SPECIFICATION
TITLE OF INVENTION
THREE-PIECE RESEALABLE CAN FOR ACIDIC LIQUID
I I .
I .
5 Field of the Invention
[OOO 11
The present invention relates to a three-piece resealable can which can store
acidic liquid, particularly acidic beverages such as fruit juice with high quality.
Priority is claimed on Japanese Patent Application No. 20 10-2 1807 1, filed
10 September 29,201 0, Japanese Patent Application No. 201 0-2701 83, filed December 3,
20 10, and Japanese Patent Application No. 20 10-270 184, filed on December 3, 20 10, the
contents of which are incorporated herein by reference.
Description of Related Art
15 [0002]
A three-piece resealable can is mostly configured of a can body member, a can
bottom member, and a cap. The can body member is a steel sheet on which a PET film
is laminated in advance except for portions to be welded. The steel sheet is rounded in
a cylindrical shape, the portions to be welded overlap with each other only by 0.3 to 0.6
20 mm, electric resistance welding is performed on the portions, and therefore, a cylindrical
can body is manufactured. ,
Flanging is performed on a lower portion of a can body and a bottom cover (a
can bottom member) is provided on the lower portion. On the other hand, in order to
provide the cap on an upper portion of the can body, after necking, threading is
25 performed so that resealability due to the cap is realized. The threading is a forming in
which rotating dies are pressed to the inner surface and the outer surface of the can body
and a shape of a thread and groove of the screw is formed in a circumferential direction
of the can body. However, at this time, a large shearing force is generated in the
circumferential direction at the place where the dies abut. Thereby, it is necessary to
t -
5 secure adhesiveness so that the laminated film is not peeled from the body material (steel
sheet) by the shearing force. In this way, the cap made of aluminum on which the
threading is performed can be screw-capped around the place subjected to the threading.
Moreover, a method is known in which a cap which does not have no thread is covered
on the can before the threading is performed, dies are pressed onto the cap, and the
10 threading is performed on the can main body and the cap together (for example, refer to
Patent Citation 1).
[0003]
In the body material of a general three-piece can, a steel sheet such as a tinplate
in which a portion of Sn is alloyed by reflow (melting treatment of Sn) after Sn is plated
15 is preferably used (for example, refer to Patent Citations 2 to 7). However, a Ni-plated
steel sheet without using Sn is also used (for example, refer to Patent Citation 8). Since
acidic beverages such as fruit juice have relatively high corrosiveness, an Sn-plated steel
sheet in which unalloyed Sn performs a sacrificial protection with respect to an iron
matrix tends to be used for the acidic beverages. On the other hand, a Ni-plated steel
20 sheet is applied for beverages having relatively low corrosiveness. Moreover, since the
Ni-plated steel sheet has significantly improved film adhesiveness, particularly, the
adhesiveness in the formed portion compared to the Sn-plated steel sheet, the Ni-plated
steel sheet is used for a member obtained by high deformation.
25 Patent Citation
[0004]
[Patent Citation 11 Japanese Unexamined Patent Application, First Publication
[Patent Citation 21 Japanese Unexamined Patent Application, First Publication
7 -
5 NO. H6-235441
[Patent Citation 31 Japanese Unexamined Patent Application, First Publication
[Patent Citation 41 Japanese Unexamined Patent Application, First Publication
10 [Patent Citation 51 Japanese Unexamined Patent Application, First Publication
[Patent Citation 61 Japanese Examined Patent Application, Second Publication
[Patent Citation 71 Japanese Examined Patent Application, Second Publication
[Patent Citation 81 Japanese Unexamined Patent Application, First Publication
NO. 2000-80499
SUMMARY OF THE INVENTION
20 Problems to be Solved by the Invention
[0005]
When the acidic beverages are filled into the three-piece resealable can, from the
viewpoint of corrosion resistance, the Sn-plated steel sheet is optimal for the body
material. However, when the threading is performed on the can body, the layer of the
25 unalloyed Sn is deformed by a large shearing force, adhesiveness between the Sn plating
and the film is damaged, and film wrinkles or film peeling are easily generated.
Moreover, the alloy Sn (alloyed Sn) has improved adhesiveness, but the corrosion
resistance with respect to the acidic beverage is not sufficient. On the other hand, in the
Ni-plated steel sheet, the problem of the above-described film peeling is not substantially
7 -
5 generated. However, since the corrosion resistance with respect to the acidic beverages
is not sufficient, the function as a can may be decreased. Thereby, a laminated
three-piece resealable can capable of filling the acidic beverages is ;equired.
Under such circumstances, an object of the present invention is to provide a
three-piece resealable can which has improved weldability, film adhesiveness, and
10 corrosion resistance and can store acidic beverages such as fruit juice with high quality.
Methods for Solving the Problem
[0006]
The inventors found that progress of the corrosion could be suppressed even
though acidic beverages were filled into a can by using an Sn-plated steel sheet (for
example, no coating and no film) in which a sacrificial protection could be used by Sn on
a bottom cover of a laminated three-piece resealable can for securing corrosion resistance,
and by using a Ni-plated steel sheet including a polyester film (for example, a PET film)
in a body material of the can for securing film adhesiveness during forming. Moreover,
when at least a portion of the Ni-plated steel sheet which is used in the body material of
the can further includes alloyed Sn plating, Sn in the Sn plating has an effect which
further suppresses the corrosion through the polyester film.
The corrosion in the can rapidly progresses due to oxygen which is mixed in at
the time of filling of the beverage and gradually proceeds after the oxygen is consumed.
That is, the inventors found the following. In an initial stage of the corrosion, the
oxygen in the can was consumed by the sacrificial protection of Sn. After the oxygen
was consumed, since the corrosion rate was significantly decreased even in the Ni-plated
steel sheet which was easily applied to a low-corrosive beverage and had relatively low
corrosion resistance, in practical use, a sufficient life span could be secured.
f -
[0007]
The summery of the present invention is as follows.
(1) A three-piece resealable can for acidic liquid according to an aspect of the
present invention includes: a cylindrical can body member that includes a screw portion
at one end; and a can bottom member that contacts the can body member so as to close
an opening portion of the other end of the can body member wherein the can body
member includes a cylindrical first steel sheet, Ni plating that is formed on an inner
circumferential surface of the first steel sheet, a polyester film that is formed so as to be
disposed on the outermost surface of an inner circumference of the can body member,
and a chromate film that is formed between the first steel sheet and the polyester film,
wherein the amount of Ni plating is 10 to 1000 mg/m2, the amount of chromate film is 2
to 30 mg/m2 expressed in terms of Cr metal, and the amount of metal plating which is
closest to the outermost surface of the inner circumference of the can body member is
200 to 4000 mg/m2, wherein the can bottom member includes a second steel sheet, and
Sn plating that is formed on the can body member side of the can bottom member, the Sn
plating being on or above the second steel sheet, and wherein the Sn plating includes Sn
single metal plating in the amount of 2 to 20 g/m2.
[0008]
(2) In the three-piece resealable can for acidic liquid according to (I), the
outermost surface on the can body member side on the can bottom member may be the
Sn plating.
(3) In the three-piece resealable can for acidic liquid according to (I), the can
bottom member may further include a chromate film which is formed on a surface of the
Sn plating, the amount of chromate film being 2 to 10 mg/m2 expressed in terms of Cr
7 -
5 metal, and the outermost surface of the can bottom member being the chromate film.
[OO lo]
(4) In the three-piece resealable can for acidic liquid according to any one of (1)
to (3), the Sn plating of the can bottom member may include alloyed Sn plating in the
amount of 0.2 to 1.5 g/m2.
(5) In the three-piece resealable can for acidic liquid according to any one of (1)
to (4), the can bottom member may further include Ni plating in the amount of 10 to 200
mg/m2 which is formed on the surface on the can body member side on the second steel
sheet.
15 [00 121
(6) In the three-piece resealable can for acidic liquid according to any one of (1)
to (5), the can bottom member may further include Ni plating in the amount of I0 to 200
mg/m2 which is formed on the surface on the can body member side of the second steel
sheet.
[00 131
(7) In the three-piece resealable can for acidic liquid according to any one of (1)
to (6), the amount of Ni plating of the can body member may be 200 to 1000 mg/m2 and
the amount of chromate film of the can body member may be 2 to 10 mg/m2 expressed in
terms of Cr metal.
[00 141
(8) In the three-piece resealable can for acidic liquid according to any one of (1)
to (6), the can body member may further include Sn plating which is formed on the
surface of the Ni plating, the Sn plating including Sn single metal plating in 0.2 to 2 g/m2
and alloyed Sn plating, the amount of Ni plating of the can body member being 10 to 200
t q
5 mg/m2, and the amount of chromate film of the can body member being 10 to 30 mg/m2.
[00 151
(9) In the three-piece resealable can for acidic liquid according to any one of (1)
to (8), the can body member may further include an adhesive layer between the chromate
film and the polyester film.
10 [00 161
(10) In the three-piece resealable can for acidic liquid according to (9), the
adhesive layer may contain 100 to 3600 mg/m2 of Sn metal particles having a mean
particle diameter of 2 to 7 pm with respect to the surface area of the first steel sheet.
[00 1 71
15 (1 1) In the three-piece resealable can for acidic liquid according to (lo), the
mean particle diameter of the Sn metal particles may be 3 to 6 pm.
[00 1 81
(12) In the three-piece resealable can for acidic liquid according to (10) or (1 I),
the adhesive layer may contain 300 to 2000 mg/m2 of the Sn metal particles with respect
20 to the surface area of the first steel sheet.
[00 1 91
(13) In the three-piece resealable can for acidic liquid according to any one of
(1) to (12), the resistance between the can body member and the can bottom member may
be 1 R or less.
25 [0020]
8
'(14) In the three-piece resealable can for acidic liquid according to (13), the
resistance between the can body member and the can bottom member may be 0.1 R or
less.
7 -
5 Effects of the Invention
According to the present invention, the three-piece resealable can which has
improved weldability, film adhesiveness, and corrosion resistance and can store acidic
beverages such as fruit juice with high quality can be provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022]
FIG. 1A is a schematic longitudinal cross-sectional view of a resealable can
according to an embodiment of the present invention.
FIG. 1B is a schematic view of a can body member when viewed from a
direction perpendicular to the sheet surface before the resealable can is manufactured.
FIG. 1C is a schematic perspective view showing the can body member after a
welding portion is welded.
FIG. ID is a schematic longitudinal cross-sectional view of the can body
member shown in FIG 1C.
FIG. 1E is a schematic longitudinal cross-sectional view of the can body member
after threading is performed.
FIG. IF is a schematic longitudinal cross-sectional view showing the can body
member just after acidic liquid is filled.
FIG. 1G is a schematic longitudinal cross-sectional view showing the resealable
9
can into which the acidic liquid is filled.
FIG. 2A is a cross-sectional view showing an example of a layer structure of the
can body member of the resealable can according to the present embodiment.
FIG. 2B is a cross-sectional view showing an example of the layer structure of
1 .
the can body member of the resealable can according to the present embodiment.
FIG. 2C is a cross-sectional view showing an example of the layer structure of
the can body member of the resealable can according to the present embodiment.
FIG. 2D is a cross-sectional view showing an example of the layer str~~cluorfe
the can body member of the resealable can according to the present embodiment.
FIG. 2E is a cross-sectional view showing an example of the layer structure of
the can body member of the resealable can according to the present embodiment.
FIG. 2F is a cross-sectional view showing an example of the layer structure of
the can body member of the resealable can according to the present embodiment.
FIG. 3A is a cross-sectional view showing an example of a layer structure of a
can bottom member of the resealable can according to the present embodiment.
FIG. 3B is a cross-sectional view showing an example of the layer structure of
the can bottom member of the resealable can according to the present embodiment.
FIG. 3C is a cross-sectional view showing an example of the layer structure of
the can bottom member of the resealable can according to the present embodiment.
FIG. 3D is a cross-sectional view showing an example of the layer structure of
the can bottom member of the resealable can according to the present embodiment.
FIG. 3E is a cross-sectional view showing an example of the layer structure of
the can bottom member of the resealable can according to the present embodiment.
FIG. 3F is a cross-sectional view showing an example of the layer structure of
the can bottom member of the resealable can according to the present embodiment.
FIG. 3G is a cross-sectional view showing an example of the layer structure of
the can bottom member of the resealable can according to the present embodiment.
FIG. 3H is a cross-sectional view showing an example of the layer structure of
the can bottom member of the resealable can according to the present embodiment.
7 -
5 FIG. 4A is a cross-sectional view showing an example of the layer structure of
the can bottom member of the resealable can according to the present embodiment.
FIG. 4B is a cross-sectional view showing an example of the layer structure of
the can bottom member of the resealable can according to the present embodiment.
FIG. 5 is a cross-sectional view showing an example of a layer structure in the
10 welding portion of the can body member of the resealable can according to the present
embodiment.
DETAILED DESCRIPTION OF THE INVENTION
COO231
Hereinafter, embodiments of the present invention will be described in detail.
A method of manufacturing a sheet (steel sheet) to be plated which is used in the
present embodiment, the material of the sheet, or the like are not particularly limited.
That is, a general slab (slab subjected to general refining and casting) is subjected to
processes such as hot rolling, pickling, cold rolling, annealing, and skin pass rolling, and
20 the sheet to be plated is manufactured.
[Ni-plated steel sheet (can body member)]
First, a case where a can body member uses a Ni-plated steel sheet will be
described.
When Ni plating is performed on a sheet to be plated, generally, degreasing and
25 pickling are performed as a pretreatment for cleaning the surface of the sheet to be plated.
11
However, the possible methods are not particularly limited. For example, after the sheet
to be plated is degreased in 10% sodium hydroxide, electrolytic pickling with respect to
the sheet may be performed in 5% sulfuric acid solution. Sequentially after the
degreasing and the pickling, the Ni plating is electrically performed on the sheet to be
: '
plated. The method of the Ni plating is also not particularly limited. For example, the
Ni plating may be performed at a current density of 1 to 5 Ndm2 in a solution of 30 to
45°C and about pH 4 which contains Ni ions at 20 to 40 g/L using Ni sulfate and boric
acid. The object which performs the Ni plating is to secure weldability, corrosion
resistance, and adhesiveness after forming. Ni has characteristics in which a solid-state
bonding is easily performed by forge welding, and therefore, improved weldability can
be exerted by the Ni plating. The improvement of the weldability due to the solid-state
bonding begins to be exerted when the amount of Ni plating is 200 mg/m2 or more and
gently increases according to an increase in the amount of Ni plating. However, if the
amount of Ni plating exceeds 1000 mg/m2, the improved weldability approaches a limit,
which is economically disadvantageous. Thereby, in the case of obtaining the
improvement of the weldability due to the solid-state bonding, it is preferable that the
amount of Ni plating be 200 to 1000 mg/m2.
[0024]
Moreover, Ni exerts more improved adhesiveness after forming through a
synergistic effect with a chromate coating film. The film (chromate film) formed by the
chromate treatment mainly contains hydrated Cr oxide which is firmly adhered to a film
(for example, a polyester film) by hydrogen bonds. The improved adhesiveness begins
to be exerted when the amount of chromate film is 2 mg/m2 or more expressed in terms
of chromium metal and gently increases according to an increase in the amount of
chromate film. On the other hand, since the chromate film has an insulating property
compared to the metal plating, if the amount of chromate film is too high, the current
required in the welding becomes unstable, and expulsion according to local heating is
easily generated. Thereby, the amount of chromate film needs to be 30 mg/m2 or less
expressed in terms of chromium metal, and is preferably 10 mg/m2 or less. Particularly,
8 I *
5 in the Ni-plated steel sheet, since the chromate film is directly formed on the surface of
Ni plating, considering affinity or the like between the Ni plating and the chromate film,
it is preferable that the chromate film be 2 to 10 mg/m2. The method of applying the
chromate film is not particularly limited. For example, the chromate film may be
obtained by performing cathode electrolysis at a current density of 1 to 5 A/dm2 in a
solution of 100 g/L of chromic acid and 1 g/L of sulfuric acid.
[0025]
[Sn-plated steel sheet (can bottom member)]
Next, a can bottom member which uses an Sn-plated steel sheet will be
described.
Also when Sn plating is performed, similarly to the Ni plating, degreasing and
pickling are performed as a pretreatment for cleaning the surface of the sheet to be plated.
However, the method is not particularly limited. For example, after the sheet lo be
plated is degreased in 10% sodium hydroxide, electrolytic pickling with respect to the
sheet may be performed in 5% sulfuric acid solution. Sequentially after the degreasing
and the pickling, the Sn plating is electrically performed on the sheet to be plated. The
method of the Sn plating is also not particularly limited. For example, the Sn plating
may be performed at 35 to 45OC and a current density of 1 to 5 A/dm2 in an acid solution
of about pH 1 which contains Sn ions at 15 to 30 g/L using sulfuric acid and Sn sulfate.
[0026]
The object of using the Sn-plated steel sheet as the can bottom member is to
13
secure corrosion resistance. In containers into which acidic beverages (acidic liquid)
are filled, Sn provides a sacrificial protection with respect to the iron matrix.
Particularly, just after the filling, that is, in the initial stage of corrosion, oxygen in the
can which promotes the corrosion and Sn react with each other, and corrosion resistance
Y *
5 is secured. The improvement of the corrosion resistance due to Sn begins to be exerted
when the amount of Sn single metal plating in the Sn plating is 2 g/m2 or more, and the
corrosion resistance gently increases according to an increase in the amount of Sn plating.
However, if the amount of Sn single metal plating exceeds 20 g/m2, the improved
corrosion resistance approaches a limit, which is economically disadvantageous.
10 Thereby, the amount of Sn single metal plating is limited to 2 to 20 g/m2. In order to
secure more sufficient corrosion resistance (for example, corrosion resistance in the
longer term), the amount of Sn single metal plating is preferably 5 g/m2 or more, and is
more preferably 8 g/m2 or more. Moreover, in order to use the Sn plating as efficiently
as possible, the amount of Sn single metal plating is preferably 16 g/m2 or less and is
15 more preferably 15 g/m2 or less. Moreover, the Sn single metal plating is defined as Sn
plating in which alloying is not applied after the Sn plating, and the amount of Sn single
metal plating is estimated as an amount independent from the amount of alloyed Sn
plating described below. Thereby, Sn single metal plating may include other elements
through a plating bath.
20 [0027]
In an Sn-plating layer (Sn plating) just after the plating is performed, invisible
micro pinholes are present and the iron matrix may be exposed. Thus, the pinholes are
removed by performing reflow (reflow of Sn) after the Sn plating, and the corrosion
resistance can be improved. In addition, in this case, since an alloyed Sn layer (alloyed
25 Sn plating) having improved corrosion resistance compared to pure Sn is formed, Sn (Sn
in the Sn single metal plating) is dissolved by a sacrificial protection effect, corrosion of
the place in which the Sn-plating layer is thinned is prevented, and dissolution of iron
(iron matrix) can be suppressed. The improvement of the corrosion resistance due to
the Sn alloy layer begins to be exerted when the amount of alloyed Sn plating is 0.2 g / ~ 2
t *
5 or more expressed in terms of Sn metal, and the corrosion resistance gently increases
according to an increase in the amount of alloyed Sn plating. However, if the amount of
alloyed Sn plating exceeds 1.5 g/m2 expressed in terms of Sn metal, the improved
corrosion resistance approaches a limit, which is economically disadvantageous.
Accordingly, it is preferable that the amount of alloyed Sn plating be 0.2 to 1.5 g/m2
10 expressed in terms of Sn metal. The method of reflow is not particularly limited, and an
apparatus which can heat up to a temperature which exceeds a melting point of Sn may
be used. For example, the reflow may be performed by electrical heating, induction
heating, or heating in an electrical furnace. Moreover, the amount of alloyed Sn plating
is estimated as an amount independent from the amount of Sn single metal plating.
15 [0028]
In addition, in the Sn-plated steel sheet which is used in the can bottom member,
the Ni plating may be performed before the Sn plating is performed. In this case, the Sn
plating is formed on the Ni plating, and the appearance of the alloyed Sn plating can be
silver-white. Generally, since Sn alloy forms a coarse surface of columnar crystals, the
20 appearance is gray or black. However, if the alloyed Sn plating is formed on the Ni
plating, since crystals of the Sn alloy become fine and are more densely precipitated, the
appearance becomes silver-white. The improvement of the appearance due to Ni begins
to be exerted when the amount of Ni plating is 10 mg/m2 or more and gently increases
according to an increase in the amount of Ni plating. However, if the amount of Ni
25 plating exceeds 200 mg/m2, the improved appearance approaches a limit, which is
economically disadvantageous. Thereby, when the Ni plating is performed on the can
bottom member, it is preferable that the amount of Ni plating be 10 to 200 mg/m2. The
method of the Ni plating is not particularly limited. For example, the above-described
method of the Ni plating may be used, and Ni-Fe alloy plating may be formed as the Ni
t *
5 plating. For example, the Ni-Fe alloy plating may be formed by plating at a current
density of 1 to 5 ~ / d m ' in a solution of 30 to 4S°C and about pH 2 to 3 which contains Ni
and Fe ions at 20 to 40 gL using Fe sulfate, Ni sulfate, and boric acid.
[0029]
Sequentially after the Sn plating, a chromate treatment may be performed in
10 order to secure the adhesiveness between the can and coating or the like. It is preferable
that a surface corresponding to the inner surface of the can of the Sn-plated steel sheet be
used in the can bottom member without being subjected to the chromate treatment.
However, a simple coating is applied to a surface corresponding to the outer surface of
the can of the Sn-plated steel sheet in order to secure corrosion resistance (rustproofness)
15 and slidability. Thereby, it is preferable that a chromate film be formed on the surface
corresponding to the outer surface of the can of the Sn-plated steel sheet so as to improve
coating properties. That is, the coating (chromate film) formed by the chromate
treatment mainly contains hydrated Cr oxide which is firmly adhered to a coating
material by hydrogen bonds. The improved adhesiveness begins to be exerted when the
20 amount of chromate film is 2 mg/m2 or more expressed in terms of chromium metal, and
the adhesiveness gently increases according to an increase in the amount of chromate
film. However, if the amount of chromate film exceeds 10 mg/m2, the improved
adhesiveness approaches a limit, which is economically disadvantageous. Thereby, it is
preferable that the amount of chromate film be 2 to 10 mg/m2 or less expressed in terms
25 of chromium metal. Moreover, if the amount of chromate film is within this range, even
-
16
when the chromate film is formed on the surface corresponding to the inner surface of the
can of the can bottom member, the improvement of corrosion resistance due to Sn
(sacrificial protection effect) can be sufficiently maintained. Thereby, the chromate film
may be formed on both surfaces of the Sn-plated steel sheet. In this case, the chromate
t -
treatment can be simply performed. In addition, the method of applying the chromate
film is not particularly limited. For example, the chromate film can be obtained by
performing cathode electrolysis at a current density of 1 to 5 A/dm2 in a solution of 40
g/L sodium dichromate at pH 4.
[0030]
[Sn-plated steel sheet (can body member)]
Moreover, the can body member which uses an Sn-plated steel sheet will be
described.
In the Sn-plated steel sheet which is used in the can body member, it is
necessary to perform the Ni plating before the Sn plating. The method of the Ni plating
is not particularly limited. For example, the above-described method of the Ni plating
may be used, and Ni-Fe alloy plating may be formed as the Ni plating. For example,
the Ni-Fe alloy plating may be formed by being performed at a current density of 1 to 5
A/dm2 in a solution of 30 to 45OC and about pH 2 to 3 which contains Ni and Fe ions at
20 to 40 g/L using Fe sulfate, Ni sulfate, and boric acid.
[003 11
The object of performing the Ni plating before the Sn plating is to secure
corrosion resistance and adhesiveness. Since the Ni is a metal having an excellent
corrosion resistance, the corrosion resistance of the Sn alloy layer (alloyed Sn plating)
containing Ni formed by the reflow can be improved. Moreover, if the Ni plating is
performed before the Sn plating, Sn which is melted by the reflow is easily repelled, the
amount of exposed portions of alloyed Sn layer having improved film adhesiveness
increases, and the amount of exposed portions of unalloyed Sn decreases. Therefore,
the film adhesiveness at the formed portion can be secured. The effect of Ni begins to
be exerted when the amount of Ni plating is 10 mg/m2 or more and gently increases
t *
5 according to an increase in the amount of Ni plating. However, if the amount of Ni
plating exceeds 200 mg/m2, the film adhesiveness approaches a limit, which is
economically disadvantageous. Therefore, it is preferable that the amount of Ni plating
be 10 to 200 mg/m2.
[0032]
The role of Sn in the Sn-plated steel sheet which is used in the can body member
is to secure weldability. Since Sn has an effect which decreases contact resistance,
electric resistance welding can be easily performed with respect to the Sn-plated steel
sheet. The improvement of weldability due to the presence of Sn begins to be exerted
when the amount of a single metal plating in the Sn plating is 0.2 g/m2 or more and the
15 weldability gently increases according to an increase in the amount of Sn single metal
plating. Moreover, if the amount of Sn single metal plating is 2 g/m2 or less, according
to the above-described effect of the Ni plating, the amount of exposed portions of alloyed
Sn plating after a reflow described below can be sufficiently secured, and the film
adhesiveness can be improved. Accordingly, in the case of obtaining the effect which
20 improves the weldability due to the decrease in the contact resistance, it is preferable that
the amount of Sn single metal plating be 0.2 to 2 g/m2. Moreover, the amount of Sn
single metal plating is estimated as an amount independent from the amount of alloyed
Sn plating described below. .
[0033]
1 In addition, in order to secure the adhesiveness, the above-described reflow is
I
i
performed. In the reflow, if the amount of the formed alloyed Sn plating is 0.2 g/m2 or
more expressed in terms of Sn metal, the adhesiveness (film adhesiveness) begins to
improve, and the adhesiveness gently increases according to an increase in the amount of
alloyed Sn plating. However, if the amount of alloyed Sn plating increases excessively,
t .-
5 it is difficult for a hard Sn alloy layer to deform properly during processing such as
threading, damage such as cracks is generated in the Sn alloy layer, and the adhesiveness
or the corrosion resistance may be significantly deteriorated. Thereby, the amount of
alloyed Sn plating is preferably 2 g/m2 or less and more preferably 1 g/m2 or less, which
are expressed in terms of Sn metal. In this way, it is preferable that the amount of
10 alloyed Sn plating be 0.2 to 2 g/m2. The amount of alloyed Sn plating can be controlled
by adjusting a temperature or time during the reflow. The method of the reflow is not
particularly limited. Industrially, the reflow may be performed by electrical heating,
induction heating, or heating in an electrical furnace. Moreover, the amount of alloyed
Sn plating is estimated as an amount independent from the amount of Sn single metal
15 plating.
[0034]
Sequentially after the Sn plating, the chromate treatment is performed in order to
secure improved film adhesiveness (adhesiveness after forming) during forming. The
coating (chromate film) formed by the chromate treatment mainly contains hydrated Cr
20 oxide and Cr metal which are firmly adhered to a film by hydrogen bonds. The
improved adhesiveness after forming begins to be exerted when the amount of chromate
film is 2 mg/m2 or more expressed in terms of chromium metal and the adhesiveness
after forming gently increases according to an increase in the amount of chromate film.
On the other hand, since the chromate film has an insulating property compared to the
25 metal plating, if the amount of chromate film is too high, a current required in the
welding becomes unstable, and expulsion according to local heating is easily generated.
Thereby, the amount of chromate film needs to be 30 mg/m2 or less expressed in terms of
chromium metal. Particularly, in the Sn-plated steel sheet, since the chromate film is
directly formed on the surface of the Sn plating, in view of an affinity or the like between
i
5 the Sn plating and the chromate film, it is preferable that the amount of chromate film be
10 to 30 mg/m2. The method of applying the chromate film is not particularly limited.
For example, the chromate film may be obtained by performing cathode electrolysis at a
current density of 10 to 40 Ndm2 in a solution of 100 g/L of chromic acid and I g/L of
sulfuric acid.
[0035]
The three-piece resealable can is manufactured using either the Ni-plated steel
sheet for the can body member or the Sn-plated steel sheet for the can body member and
the Sn-plated steel sheet for the can bottom member. The method of manufacturing the
three-piece resealable can is not particularly limited. For example, the method of
manufacturing the three-piece resealable can may use the method disclosed in Patent
Citation 1.
[0036]
Moreover, in the embodiment, as the Sn-plated steel sheet configuring the
bottom cover, an Sn-plated steel sheet in which an organic coating is not applied to a
surface corresponding to the inner surface of the can is used. Here, the organic coating
is defined as a general coating film (organic coating film) or laminate resin film which is
used in a can main body. That is, in the embodiment, because a defective portion of the
can body is protected by the sacrificial protection due to the Sn plating in which the
organic coating is not formed in at least the portion in which the inner surface of the can
in the bottom cover contacts the contents of the can.
20
[0037]
Moreover, in order to further enhance the adhesiveness between the polyester
film and the chromate film, an adhesive layer may be formed between the chromate film
and the polyester film (on the chromate film of the can body member). The adhesive
t *
5 resin which is used in the adhesive layer is not particularly limited, and may be an
adhesive which is generally used in order to laminate a resin film on the steel sheet.
The adhesive resin may use either a thermoplastic resin or a thermosetting resin.
However, from the viewpoint of heat resistance, it is preferable that the thermosetting
resin be used.
For example, the thermosetting resin may include a composition or the like in
which a hardening agent such as a melamine resin or an isocyanate resin is added to at
least one kind selected from a polyester-based resin, an urethane-based resin, an
epoxy-based resin, an acryl-based resin, an amino-based resin, a phenol-based resin, and
the like, or at least one kind of these resins.
15 Moreover, a white pigment may be added to the adhesive layer and the adhesive
layer may include 20 to 80 wt.% of inorganic pigments such as titanium oxide or mica.
[003 81
Moreover, as the polyester film which is used in the can body member, films
such as polyethylene naphthalate or polyethylene terephthalate (PET) are used.
20 However, among these, a film (PET film) containing the polyethylene terephthalate as a
main chemical component is preferably used. In order to secure dimensional stability
with respect to heat treatment, generally, the polyester film uses a biaxially stretched film.
The thickness of the film is not particularly limited. However, a film having the
thickness of about 8 to 250 pm may be used, for example, from the viewpoint of costs,
25 handling properties, and the formability, and the film having a thickness of 12 to 25 pm
may be preferably used.
[0039]
As described above, the inventors found that the corrosion resistance of the can
main body could be secured using the Sn-plated steel sheet, in which the sacrificial
t .
protection due to Sn could be used, in the bottom cover of the laminated three-piece
resealable can. Moreover, as described below, the inventors found that it was very
important to decrease the resistance between the can bottom and the can body of the can
main body after securing the film adhesiveness during forming by using the Ni-plated
steel sheet as a material of the can body in order to suppress the corrosion of the can
main body after filling acidic liquid.
[0040]
Another point of the embodiment is to decrease (for example, to 1 R or less) the
resistance between the bottom cover (can bottom member) and the can body (can body
member) in the can main body. Generally, from the viewpoint of preventing bimetallic
corrosion, it is considered to be preferable that the resistance between the bottom cover
and the can body be high. However, in the three-piece resealable can for acidic liquid
of the embodiment, since the sacrificial protection of the can body is performed by the Sn
plating of the can bottom, the resistance between the bottom cover and the can body is
preferably 1 R or less and is more preferably 0.1 SZ or less.
In this way, when the resistance between the bottom cover and the can body is 1
0 or less, the inventors found that a cell could be formed between Sn of the bottom cover
and Ni or Fe of the can body, the sacrificial protection effect of Sn was sufficiently
exerted, and the corrosion of the can body portion could be suppressed.
[004 11
The method of decreasing the resistance between the can cover and the can body
is not particularly limited. In the embodiment, on the surface of the can cover
corresponding to the inner surface side of the can main body, an organic film is not used
except for a sealing compound which is applied to a seamed portion for securing sealing
performance. Thereby, for example, as the method of decreasing the resistance, there is
r *
5 a method in which the organic film of the can body portion contacting the can cover
portion other than the area to which the sealing compound is applied when the can
bottom member is seamed to the can body member is removed mechanically, physically,
or chemically.
In addition, for example, there is a method in which the sealing compound is
10 applied only to the inner side (the inner side with respect to a general position) with
respect to a sealing panel (can bottom member). Moreover, for example, when a shear
blanking of the can body member is performed, there is method in which the shear is
performed so that a burr protrudes in a direction of the can outer surface in a can end of
the can body member on the side seaming the can cover. In this case, since the metal
15 portion of the burr and the can bottom member easily contact each other, even though the
organic film on the outer surface side of the can body is not removed, an electric
connection between the can body member and the can bottom member can be secured.
COO421
In addition, as described below, the inventors found that progress of the
20 corrosion after acidic beverages were filled could be suppressed while the film
adhesiveness was secured during the forming due to the fact that Sn metal particles
having a specific particle diameter (particle size) were contained in the adhesive layer
between the Ni-plated steel sheet and the polyester film at a specific ratio. That is, the
inventors found that if Sn metal particles were used in the can body member, oxygen in
25 the can and particles of the metal Sn reacted with each other and oxygen in the can was
consumed in an initial stage of corrosion, the corrosion rate decreased significantly even
in the Ni-plated steel sheet which was easily applied to beverages having low
corrosiveness after the oxygen was consumed, and in practical use, sufficient film
adhesiveness and can life span could be secured. In this case, both the sacrificial
t .
5 protection effect due to Sn of the can bottom member and the sacrificial protection effect
due to Sn of the adhesive layer in the can body member can be obtained, and long-term
corrosion resistance of the can main body can be realized.
[0043]
Still another point of the embodiment is that the adhesive layer of the surface
10 corresponding to at least the inner surface of the can in a laminate steel sheet (Ni-plated
steel sheet) of a resin film for a can includes Sn metal particles having a mean particle
diameter of preferably 2 to 7 pm, more preferably 3 to 6 pm, in preferably 100 to 3600
mg/m2, more preferably 300 to 2000 mg/m2 per surface area of the steel sheet.
[0044]
15 First, an advantage when Sn metal particles are contained in the adhesive layer
will be described.
In an atmosphere inside the can into which acidic beverages are filled, tin (Sn) is
baser than iron (Fe) or nickel (Ni), and is oxidized earlier than the nickel or iron. Just
after the filling, that is, in the initial stage of the corrosion, oxygen inside the can
20 promotes the corrosion. Due to the fact that the oxygen inside the can reacts with the
Sn metal particles, the corrosion of the steel ;beet after the reaction can be delayed and
the corrosion resistance is secured. Moreover, when only Sn is plated on the steel sheet
and the Sn-plated steel sheet in which alloying is not performed is used in the can body
member, as described above, the film is easily separated in a formed portion (screw
25 formed portion) such as a screw.
The reason why it is preferable that the mean particle diameter of Sn metal
particles be 2 to 7 pm will be described.
When the mean particle diameter of the Sn metal particles is less than 2 pm,
C, *
5 there is a tendency of making the appearance darker. Therefore, when a good
appearance of the inner surface of the can main body is required, it is preferable that the
mean particle diameter of the Sn metal particles be 2 pm or more. In addition, it is
considered that the decrease in the brightness of the appearance is due to effects of the
increase in scattering frequency of light according to the increase in the number of
10 particles. Moreover, when the mean particle diameter of the Sn metal particles exceeds
7 pm, in the adhesive layer having the average thickness of about 5 pm or less, in a case
where only the diameter of the particles of the metal Sn increases while the thickness of
the adhesive layer is not changed, air is caught in an adhesive interface, it is difficult to
secure sufficient adhesiveness between the adhesive layer and the steel sheet (Ni-plated
15 steel sheet) or the adhesive layer and a resin film (polyester film). Moreover, in this
case, the Sn metal particles themselves are deformed during forming, for example, the
adhesiveness of the screw formed portion easily decreases. Therefore, the mean particle
diameter of the Sn metal particles is preferably 2 to 7 pm and is more preferably 3 to 6
In addition, the mean particle diameter of the Sn metal particles which are used
in the embodiment is a value which is measured by a laser diffraction particle size
analyzer (SALD-2000J manufactured by Shimadzu Corporation).
[0046]
Next, the reason why it is preferable that the amount of Sn metal particles which
25
are contained in the adhesive layer be 100 to 3600 mg/m2 per surface area of the steel
sheet will be described.
If the amount of Sn metal particles is 100 mg/m2 or more per surface area of the
steel sheet, the corrosion resistance of the can body member can be further enhanced.
t .
5 Moreover, when the amount of Sn metal particles is 3600 mg/m2 or less per surface area
of the steel sheet, since the color tone of the coated film (polyester film and adhesive
layer) can be brightly maintained, the appearance in the inner surface of the can is
improved. Moreover, in this case, the film adhesiveness of the screw formed portion
can be sufficiently secured.
Therefore, the amount of Sn metal particles which are contained in the adhesive
layer is preferably 100 to 3600 mg/m2 and more preferably 300 to 2000 mg/m2 per
surface area of the steel sheet.
[0047]
In addition, the configuration of the three-piece resealable can (hereinafter,
15 referred to as a "resealable can") for acidic liquid of the embodiment will be further
described with reference to the accompanying drawings.
FIG. 1A is a schematic longitudinal cross-sectional view of the resealable can of
the embodiment. As shown in FIG. lA, the resealable can 1 of the embodiment
includes a cylindrical can body member 2 which includes a screw portion (screw formed
20 portion) 21 at one end, a can bottom member 3 which contacts the can body member 2 so
as to close an opening portion of the other end of the can body member 2, and a cap 4
which is screwed to the screw portion 2 1 of the can body member 2. As described
above, the end of the can body member 2 and the end of the can bottom member 3 are
seamed to each other, the lower portion of the resealable can 1 is sealed, and a can main
25 body 5 is formed. Similarly, the cap 4 is screwed to the can body member 2, and
therefore, the upper portion of the resealable can 1 is closed to be resealable.
Moreover, it is preferable that the shape of the resealable can 1 satisfy the
above-described configuration. However, the shape of the resealable can is not limited
to the shape of FIG. 1A. Generally, aluminum is used in the material of the cap 4.
t .
5 However, if effects of the embodiment are not damaged, any material (for example, the
same material as that of the can body member 2) may be used.
[0048]
Moreover, FIGS. 1B to 1G schematically show a method of manufacturing the
can main body of the embodiment. As shown in FIG. IB, the can body member 2
10 before the resealable can 1 is manufactured is a sheet shape, and includes welding
portions 22 and a polyester film 23 when viewed from a direction perpendicular to the
sheet surface. The welding portions 22 are formed along two sides which face each
other in the sheet surface of the can body member 2, and an organic film such as a
polyester film 23 is not formed on the surfaces of the welding portions 22. The
15 sheet-shaped can body member 2 is formed in a cylindrical shape. For example, the
welding portions 22 overlap with each other and are welded by electric resistance
welding (lap welding), as shown in FIGS. 1C and 1D (a longitudinal cross-sectional view
of FIG lC), such that the cylindrical can body member 2 can be obtained. Moreover,
the threading is performed on the cylindrical can body member 2, and the screw portion
20 21 shown in FIG. 1E is formed. The cap 4 is mounted on the screw portion 21, as
shown in FIG IF, and acidic liquid 100 (for example, acidic beverages) is filled from an
opening portion of the end opposite to the end in which the screw portion 21 of the can
body member 2 is formed. After the acidic liquid 100 is filled, as shown in FIG. 1G the
end (end of the opening portion side) of the can body member 2 and the end of the can
25 bottom member 3 are seamed to each other so as to close the opening portion, and the
27
resealable can 1 into which the acidic liquid 100 is filled is manufactured. Moreover,
the acidic liquid 100 is not particularly limited, and may be an acidic beverage such as
orange juice.
[0049]
t ,*
5 In the resealable can 1 of the embodiment, for example, a plated steel sheet
having a layer configuration shown in FIGS. 2A to 2F may be used in the can body
member 2. FIGS. 2A to 2F schematically show an area A which is enclosed by a dashed
line in FIG 1A. Moreover, the layer configuration may be applied to at least the inner
surface of the can main body 5 and may be also applied to both surfaces (inner surface
10 and outer surface) of the can main body 5. As shown in FIGS. 2A to 2F, the can body
member 2 includes a cylindrical steel sheet (a first steel sheet, a sheet to be plated) 26, Ni
plating 25 which is formed on the inner circumference surface of the steel sheet 26, a
polyester film 23 which is formed so as to be disposed on the outermost surface of the
inner circumference of the can body member 2, and a chromate film 24 which is formed
15 between the polyester film 23 and the steel sheet 26 (or, Ni plating 25). As described
above, the amount of Ni plating 25 of the can body member 2 is 10 to 1000 mg/m2, and
the amount of chromate film 24 is 2 to 30 mg/m2 expressed in terms of Cr metal.
Moreover, in order to secure weldability, the amount of metal plating which is the closest
to the outermost surface of the inner circumference of the can body member (in FIGS. 2A
20 to 2F, Ni plating 25 or Sn plating 27 (that is, the Sn single metal plating 27A and alloyed
Sn plating 27B)) is required to be 200 to 4000 mg/m2.
[0050]
In addition, in FIGS. 2A, 2C, and 2E, an example of the above-described
Ni-plated steel sheet for the can body member is shown. In FIG. 2A, the can body
25 member 2A includes the steel sheet 26, the Ni plating 25 which is formed on the surface
of the steel sheet 26, the chromate film 24 which is formed on the surface of the Ni
plating 25, and the polyester film 23 which is formed on the surface of the chromate film
24. In Fig. 2C, the can body member 2C includes the steel sheet 26, the Ni plating 25
which is formed on the surface of the steel sheet 26, the chromate film 24 which is
t .
formed on the surface of the Ni plating 25, an adhesive layer 28 which is formed on the
surface of the chromate film 24, and a polyester film 23 which is formed on the surface
of the adhesive layer 28. In the can body member 2E of FIG 2E, the adhesive layer 28
contains Sn metal particles 28A in the layer configuration similar to that of FIG. 2C.
coo5 11
Similarly, FIGS. 2B, 2D, and 2F show an example of the above-described
Sn-plated steel for the can bottom member. In FIGS. 2B, 2D, and 2F, the Sn plating 27
which is formed on the surface of the Ni plating 25 is further provided. In FIG. 2B, the
can body member 2B includes the steel sheet 26, the Ni plating 25 which is formed on
the surface of the steel sheet 26, the Sn plating 27 which is formed on the surface of the
Ni plating 25, the chromate film 24 which is formed on the surface of the Sn plating 27,
and the polyester film 23 which is formed on the surface of the chromate film 24. In
FIG. 2D, the can body member 2D includes the steel sheet 26, the Ni plating 25 which is
formed on the surface of the steel sheet 26, the Sn plating 27 which is formed on the
surface of the Ni plating 25, the chromate film 24 which is formed on the surface of the
Sn plating 27, the adhesive layer 28 which is formed on the surface of the chromate film
24, and the polyester film 23 which is formed on the surface of the adhesive layer 28.
In the can body member 2E of FIG. 2E, the adhesive layer 28 contains Sn metal particles
28A in the layer configuration similar to that of FIG. 2D. Moreover, in FIGS. 2B, 2D,
and 2F, the Sn plating 27 is alloyed and includes the Sn single metal plating 27A and the
alloyed Sn plating 27B.
29
[0052]
Moreover, the polyester film 23 is not formed on the welding portion 22 of the
can body member 2. Therefore, if the layer configuration of the non-welding portion of
the can body member 2 is the layer configuration shown in FIG. 2A, the layer
: -
5 configuration of the welding portion 22 is the layer configuration shown in FIG. 5.
Moreover, FIG. 5 schematically shows a longitudinal cross section of the welding portion
22 (area D) corresponding to the area A which is enclosed by the dashed line in FIG. 1A.
In the resealable can 1 of the embodiment, for example, a plated steel sheet
10 having a layer configuration shown in FIGS. 3A to 3H can be used in the can bottom
member 3. FIGS. 3A to 3H schematically show an area B which is enclosed by a
dashed line in FIG. 1A. Moreover, this layer configuration may be applied to at least
the inner surface of the can main body 5 and may be also applied to both surfaces (inner
surface and outer surface) of the can main body 5. As shown in FIGS. 3A to 3H, the
15 can bottom member 3 includes a steel sheet (second steel sheet, sheet to be plated) 36
and Sn plating 37 which is formed on the can body member 2 side of the steel sheet 36
(inner surface side of can main body 5). As described above, the Sn plating 27 of the
can bottom member 3 includes Sn single metal plating of the amount of 2 to 20 mg/m2.
[0054]
20 Moreover, FIGS. 3A to 3H show an example of the above-described Sn-plated
steel sheet for the can bottom member. In FIG. 3A, the can bottom member 3A includes
the steel sheet 36 and the Sn plating 37 which is formed on the surface of the steel sheet
36. In FIG. 3B, the can bottom member 3B includes the steel sheet 36, the Sn plating 37
which is formed on the surface of the steel sheet 36, and a chromate film 34 which is
25 formed on the surface of the Sn plating 37. Similarly, in FIG. 3C, the can bottom
-
30
member 3C includes the steel sheet 36, the Sn plating 37 which is formed on the surface
of the steel sheet 36, and the chromate film 34 which is formed on the surface of the Sn
plating 37. In FIG. 3D, the can bottom member 3D includes the steel sheet 36, Ni
plating 35 which is formed on the surface of the steel sheet 36, and the Sn plating 37
t .
5 which is formed on the surface of the Ni plating 35. In FIG. 3E, the can bottom member
3E includes the steel sheet 36, the Ni plating 35 which is formed on the surface of the
steel sheet 36, the Sn plating 37 which is formed on the surface of the Ni plating 35, and
the chromate film 34 which is formed on the surface of the Sn plating 37. Similarly, in
FIG. 3F, the can bottom member 3F includes the steel sheet 36, the Ni plating 35 which is
10 formed on the surface of the steel sheet 36, the Sn plating 37 which is formed on the
surface of the Ni plating 35, and the chromate film 34 which is formed on the surface of
the Sn plating 37. In FIG. 3G, the can bottom member 3G includes the steel sheet 36
and the Sn plating 37 which is formed on the surface of the steel sheet 36. In FIG. 3H,
the can bottom member 3H includes the steel sheet 36, the Ni plating 35 which is formed
15 on the surface of the steel sheet 36, and the Sn plating 37 which is formed on the surface
of the Ni plating 35.
[0055]
Here, in FIGS. 3A, 3D, 3Q and 3H, the outermost surface on the can body
member 2 side of the can bottom member 3 is the Sn plating 37, and in FIGS. 3B, 3C, 3E,
20 and 3F, the outermost surface on the can body member 2 side of the can bottom member
3 is chromate film 34. In addition, in FIGS. 3D to 3F, and 3H, the can bottom member
3 includes the Ni plating 35 which is formed on the surface on the can body member 2
side of the can bottom member 3 on or above the steel sheet 36. Moreover, in FIGS. 3A,
3B, 3D, and 3E, the Sn plating 37 includes only the Sn single metal plating 37A. In
25 addition, in FIGS. 3C, 3F, 3G, and 3H, the Sn plating 37 includes both the Sn single
metal plating 37A and alloyed Sn plating.
[0056]
Moreover, as described above, the chromate film 34 is formed so as to improve
the coatability of the outer surface of the can main body 5. However, in order to easily
7 -
5 perform the chromate treatment, for example, as shown in a can bottom member 31 of
FIG. 4A, the chromate film 34 may be formed on both surfaces of the can bottom
member 3. Moreover, in order to effectively exert the sacrificial protection effect of the
Sn plating 37 as possible, for example, as shown in a can bottom member 35 of FIG. 4B,
the chromate film 34 may be only formed on the outer surface of the can main body 5.
10 In addition, for example, FIGS. 4A and 4B schematically show an area C which is
enclosed by a dashed line in FIG. 1A.
[0057]
In the embodiment, the can body 5 can be manufactured by variously combining
the above-described can body member 2 and the can bottom member 3. Moreover, by
15 appropriately controlling or selecting the processing method when seaming the can body
member 2 and the can bottom member 3, the resistance between the can body member 2
and the can bottom member 3 may be controlled as described above. For example, in
the resistance of this case, the resistance between the metal surface (various platings or
sheets to be plated) of the can body member 2 and the metal surface (various platings or
20 sheets to be plated) of the can bottom member 3 may be measured while the seamed
position is interposed.
[005 81
For example, in the embodiment, as described below, by controlling an amount
of each layer (each plating and film) and order of the lamination, the can main body
25 suitable as a container for filling acidic liquid can be provided.
3 2
(A) A three-piece resealable can for acidic liquid is provided in which a steel
sheet without a coating and film in which Sn plating is applied to one surface at 2 to 15
glm2 is used in the can bottom portion of the can main body subjected to the threading,
and a steel sheet in which Ni plating is applied to one surface at 200 to 1000 mg/m2,
t *
5 subsequently, a chromate film is applied at 2 to 10 mg/m2 expressed in terms of Cr metal,
and a PET film is laminated is used in the can body portion.
(B) A three-piece resealable can for acidic liquid is provided in which a steel
sheet without a coating and film in which Sn plating is applied to one surface at 2 to 15
g/m2, and subsequently, a chromate film is applied at 2 to 10 mg/m2 expressed in terms of
10 Cr metal is used in the can bottom portion of the can main body subjected to the
threading, and a steel sheet in which Ni plating is applied to one surface at 200 to 1000
mg/m2, a chromate film is applied at 2 to 10 mg/m2 expressed in terms of Cr metal, and a
PET film is laminated is used in the can body portion.
(C) A three-piece resealable can for acidic liquid is provided in which a steel
15 sheet without a coating and film in which Sn plating is applied to one surface at 2 to 15
g/m2 is used in the can bottom portion of the can main body subjected to the threading,
and a steel sheet in which Ni plating is applied to one surface at 10 to 200 mg/m2,
subsequently, Sn plating is applied at 0.2 to 2 glm2, Sn is alloyed by performing reflow,
thereafter, a chromate film is applied at 10 to 30 mg/m2 expressed in terms of Cr metal,
20 and a PET film is laminated is used in the can body portion.
(D) A three-piece resealable can for acidic liquid is provided in which a steel
sheet without a coating and film in which Sn plating is applied to one surface at 2 to 15
dm2, subsequently, a chromate film is applied at 2 to 10 mg/m2 expressed in terms of Cr
metal is used in the can bottom portion of the can main body subjected to the threading,
25 and a steel sheet in which Ni plating is applied to one surface at 10 to 200 mg/m2,
subsequently, Sn plating is applied at 0.2 to 2 g/m2, Sn is alloyed by performing reflow,
thereafter, a chromate film is applied at 10 to 30 mg/m2 expressed in terms of Cr metal,
and a PET film is laminated is used in the can body portion.
(E) A three-piece resealable can for acidic liquid is provided in which the reflow
y ,.
5 is performed after the Sn plating and Sn of 0.2 g/m2 to 1.5 g/m2 is alloyed in the
Sn-plated steel sheet which is used in the can bottom portion according to any one of (A)
to @I.
(F) A three-piece resealable can for acidic liquid is provided in which the Ni
plating is applied to one surface at 10 to 200 mg/m2 before the Sn plating in the Sn-plated
10 steel sheet which is used in the can bottom portion according to any one of (A) to (E).
[0059]
Moreover, for example, in the embodiment, as described below, a more suitable
can main body can be provided by controlling the resistance between the can cover and
the can body.
15 (G) A three-piece resealable can for acidic liquid is provided in which a
resistance between a can body and a bottom cover is 1 Q or less in a can main body
including the can body which is formed by performing threading to a Ni-plated steel
sheet in which Ni plating is formed at 200 to 1000 mg/m2 per one surface, a chromate
film is formed at 2 to 10 mg/m2 expressed in terms of Cr metal, and a polyester film is
20 laminated on a surface corresponding to at least the inner surface of the can through an
adhesive layer, and the bottom cover which is formed by an Sn-plated steel sheet in
which Sn plating is formed at 5 to 20 g/m2 per one surface, subsequently, a chromate film
is formed at 2 to 10 mg/m2 expressed in terms of Cr metal, and an organic coating does
not formed in a portion which contacts at least the contents (liquid) in the inner surface of
25 the can.
(H) A three-piece resealable can for acidic liquid is provided in which the
bottom cover formed by the Sn-plated steel sheet is configured by forming Sn plating of
8 to 16 g/m2 per one surface, subsequently, by forming the chromate film of 2 to 10
mg/m2 expressed in terms of Cr metal, in the three-piece resealable can according to (G).
t -
(I) A three-piece resealable can for acidic liquid is provided in which the
resistance between the can body and the bottom cover is 0.1 Q or less, in the three-piece
resealable can according to (H).
Moreover, for example, in the embodiment, as described below, a more suitable
10 can main body can be provided by including Sn metal particles in the adhesive layer.
That is,
(J) A three-piece resealable can for acidic liquid is provided in which, in a can
main body including a can body portion configured by performing threading with respect
to a steel sheet which is configured by forming Ni plating of 200 to 1000 mg/m2 per one
15 surface, subsequently, by forming a chromate film of 2 to 10 mg/m2 expressed in terms of
Cr metal, and by laminating a polyester film on at least one surface corresponding to the
inner surface of the can through the adhesive layer, Sn metal particles having the mean
particle diameter of 2 to 7 pm are contained in the adhesive layer at 100 to 3600 mg/m2
of the steel sheet (as an amount per surface area).
(K) A three-piece resealable can for acidic liquid is provided in which the mean
particle diameter of the Sn metal particles is 3 to 6 pm, in the three-piece resealable can
according to (J).
(L) A three-piece resealable can for acidic liquid is provided in which the Sn
metal particles are contained at 300 to 2000 mg/m2 of the steel sheet (as an amount per
25 surface area), in the three-piece resealable can according to (J) or (K).
Examples
Hereinafter, the present invention will be described in detail according to
examples. However, the present invention is not limited to the examples as long as the
y ,.
5 solution thereof is not changed.
[0062]
First, manufacturing methods of the Ni-plated steel sheet (mainly used for can
body member) and the Sn-plated steel sheet (used for can body member and can bottom
member), which are used in the following examples, are described.
[0063]
(Manufacturing Method 1) Ni plating was applied to both surfaces of a sheet
to be plated (steel sheet) which was subjected to annealing and skin pass after cold
rolling and had a thickness of 0.19 mm, by applying a current of a current density of 1
A/dm2 in a solution of 45°C and pH 4 including Ni ions of 40 g L using Ni sulfate and
15 boric acid. Subsequently, by performing chromate treatment with respect to both
surfaces of the steel sheet through cathode electrolysis at a current density of 5 A/dm2 in
a solution of 100 g/L chromic acid and 1 g/L, sulfuric acid at 45OC, the Ni-plated steel
sheet was manufactured. The Ni-plated steel sheet was cut down to a length of 11 0 mm
and a width of 170 mm, a PET film which was biaxially stretched and had a thickness of
20 15 pm was laminated on both surfaces of the sheet except for the vicinity of the vertical
edges which became the portions to be welded, and the Ni-plated steel sheet for the can
body member was manufactured.
[0064]
(Manufacturing Method 2) Ni plating was applied to both surfaces of a sheet
25 to be plated (steel sheet) which was subjected to annealing and skin pass after cold
36
rolling and had a thickness of 0.19 mm, by applying a current of a current density of 10
A/dm2 in a solution of 45°C and pH 2.5 including Ni ions of 40 g/L. and Fe ions of 20 g/L
using Ni sulfate, Fe sulfate, and boric acid. Subsequently, by preparing an Sn plating
solution of pH 1.1 including Sn ions of 20 g/L using Sn sulfate and sulfuric acid,
I *
5 applying Sn plating to both surfaces of the steel sheet at 45°C and 2 A/dm2, and
performing reflow and chromate treatment, the Sn-plated steel sheet was manufactured.
In the reflow, the steel sheet was cooled by 60°C water just after being heated up to about
245 "C through an electric heating method. In the chromate treatment, the cathode
electrolysis was performed at a current density of 20 Ndm2 in a solution of 100 g/L
10 chromic acid and 1 g/L sulfuric acid. The Sn-plated steel sheet was cut down to a
length of 11 0 mm and a width of 170 mm, a PET film which was biaxially stretch'ed and
had a thickness of 15 pm was laminated on both surfaces of the sheet except for the
vicinity of the vertical edges which became the portions to be welded, and the Sn-plated
steel sheet for the can body member was manufactured.
(Manufacturing Method 3) Ni plating was applied to both surfaces of a sheet
to be plated (steel sheet) which was subjected to annealing and skin pass after cold
rolling and had a thickness of 0.19 mm, by applying a current of a current density of 1
A/dm2 in a solution of 45°C and pH 4 including Ni ions of 40 g/L. using Ni sulfate.
Subsequently, by preparing an Sn plating solution of pH 1.1 including Sn ions of 20 g/L
using Sn sulfate and sulfuric acid, applying Sn plating to both surfaces of the steel sheet
at 45°C and 2 ~ / d ma~nd, p erforming reflow and chromate treatment, the Sn-plated steel
sheet was manufactured. In the reflow, the steel sheet was cooled by 60°C water just
after being heated up to about 245°C through an electric heating method. In the
chromate treatment, the cathode electrolysis was performed at a current density of 20
A/dm2 in a solution of 100 g/L chromic acid and 1 gL sulfuric acid. The Sn-plated
steel sheet was cut down to a length of 11 0 mm and a width of 170 mm, a PET film
which was biaxially stretched and had a thickness of 15 pm was laminated on both
f ,*
5 surfaces of the sheet except for the vicinity of the vertical edges which became the
portions to be welded, and the Sn-plated steel sheet for the can body member was
manufactured.
In addition, the Sn-plated steel sheet for the can bottom member was
10 manufactured by the following methods.
(Manufacturing Method 4) Sn plating was applied to both surfaces of a sheet
to be plated (steel sheet) which was subjected to annealing and skin pass after cold
rolling and had a thickness of 0.19 mm, at 45°C and 2 A/dm2 in an Sn plating solution of
15 pH 1.1 including Sn ions of 20 g/L prepared using Sn sulfate and sulfuric acid, reflow
and chromate treatment were performed as necessary, and the Sn-plated steel sheet was
manufactured. In the reflow, the steel sheet was cooled by 60°C water just after being
heated up to about 245°C through an electric heating method. In the chromate
treatment, the cathode electrolysis was performed at a current density of 3 A/dm2 in a
20 solution of 40 g/L sodium dichromate at pH 4.
[0068]
(Manufacturing Method 5) After the Ni plating was applied to both surfaces of
a sheet to be plated (steel sheet) which was subjected to annealing and skin pass after
cold rolling and had a thickness of 0.19 mm using the same conditions as in the
-
3 8
Manufacturing Method 2, Sn plating was applied at 45°C and 2 A/dm2 in an Sn plating
solution of pH 1.1 including Sn ions of 20 gL prepared by using Sn sulfate and sulfuric
acid, reflow and chromate treatment were performed as necessary, and the Sn-plated steel
sheet was manufactured. In the reflow, the steel sheet was cooled by 60°C water just
Y *
after being heated up to about 245°C through an electric heating method. In the
chromate treatment, the cathode electrolysis was performed at a current density of 3
A/dm2 in a solution of 40 g/L sodium dichromate at pH 4.
[0069]
(Manufacturing Method 6) After Ni plating was applied to both surfaces of a
sheet to be plated (steel sheet) which was subjected to annealing and skin pass after cold
rolling and had a thickness of 0.19 mm using the same conditions as in the
Manufacturing Method 3, Sn plating was applied at 45°C and 2 A/dm2 in an Sn plating
solution of pH 1.1 including Sn ions of 20 g/L prepared by using Sn sulfate and sulfuric
acid, reflow and chromate treatment were performed as necessary, and the Sn-plated steel
sheet was manufactured. In the reflow, the steel sheet was cooled by 60°C water just
after being heated up to about 245°C through an electric heating method. In the
chromate treatment, the cathode electrolysis was performed at a current density of 3
Ndm2 in a solution of 40 g/L sodium dichromate at pH 4.
[0070]
The steel sheets manufactured by the above-described Manufacturing Methods 1
to 6 were applied to the can body member and the can bottom member according to
combinations shown in Table 1. In addition, by adjusting conditions such as treatment
time in each of the Manufacturing Methods 1 to 6, the amount of each layer of Nos. 1 to
25 (the amount of Ni plating, the amount of Sn single metal plating, the amount of
alloyed Sn plating, and the amount of chromate film) were adjusted. Among the layers,
with respect to the amount of Ni plating and the amount of chromate film (moreover, the
amount expressed in terms of Cr metal), each of the amount of Ni metal and the amount
of Cr metal was estimated through an ICP (inductively coupled plasma) spectroscopic
t *
5 analysis. In addition, with respect to the amount of Sn single metal plating and the
amount of alloyed Sn plating, the amount of Sn was estimated through a SEM-EDX
(scanning electron microscope/energy dispersive X-ray spectroscopy). Moreover, the
alloyed Sn plating was determined to be an area in which Fe and Ni were detected in the
Sn plating, and Sn single metal plating was determined to be an area in which Fe and Ni
10 were not detected in the Sn plating.
[0071]
Hereinafter, estimation methods will be described. Moreover, with respect to
Nos. 1 to 25 in Table 1, each of the following estimation items (1) to (4) was estimated.

15 (1) Weldability
Various PET resin film laminated-steel sheets (steel sheets for can body
member) which were manufactured were welded at a welding speed of 550 cpm by using
a welder of Soudronic AG In addition, in the welding, the overlapped portion of the
portions to be welded was set to 0.4 mm, and the pressing force was set to 45 daN. The
20 weldability was generally determined from a size of an adequate current range and
continuity of a weld nugget and was estimated to be in one of four grades (A: very good,
B: good, C: bad, D: welding impossible). Here, the adequate current range is a current
range which includes a minimum current value in which sufficient welding strength is
obtained and a maximum current value in which welding defects such as expulsion and a
25 weld spatter begin to be significant when the welding current is changed and the welding
is performed.
[0072]
(2) Film Adhesiveness of Screw Formed Portion
Threading was performed on the can body, which pinches the upper portion of
7 '.
5 the can body after the welding between two dies while rotating two cylindrical dies
including grooves having lmm of a pitch at 150 rpm and forms a thread and groove
having lmm of a height and lmm of a pitch. Thereafter, retorting of 125°C and 30
minutes was performed, and a separation resistance of the film of the screw formed
portion was estimated to be in one of four grades (A: separation (peel-off) was not
10 present at all after threading and retorting, B: separation was not present after the
forming and slight separation which was not a problem in practical use was present after
the retorting, C: minor peeling was present after the forming, and D: separation was
present over most thereof after the forming).
[0073]
(3) Corrosion Resistance
The can body portion (screw portion) subjected to the threading was covered
with a cap made of aluminum, commercially available 100% orange juice (acidic
beverage) was filled, the can cover was seamed to the can body, and the can was
manufactured. After the can was stored at 30°C for six months, the contents were
20 extracted, the amount of dissolved iron was measured, and corrosion of the inner surface
of the can was observed. The observation of the corrosion was performed by visually
observing mainly the screw portion, and the corrosion resistance was estimated to be in
one of four grades (A: corrosion was not observed at all in screw portion and flat sheet
portion, B: corrosion was not observed at all in flat sheet portion while slight corrosion
25 which was not a problem in practical use was observed in screw portion, C: slight
corrosion was observed in screw portion and flat sheet portion, and D: severe corrosion
was observed in the screw portion, and corrosion was also observed in flat sheet portion).
The appearance (appearance of can bottom afler test) of the alloyed layer exposed on the
can bottom (can cover) was also observed.
5 [0074]
(4) Adhesiveness of Coating Material of Can Bottom Member (Adhesiveness of
Coating Material of Outer Surface of Can Bottom)
Epoxy phenol resin was coated on the Sn-plated steel sheet for the can bottom
member, baking of 200°C and 30 minutes was performed, thereafter, cover forming was
10 performed so as to be used as the can bottom member. A tape peeling test was
performed to a curled portion or a countersink portion formed by the cover forming, and
the peeling resistance was estimated.
In addition, grid-like marking-off having depths reaching the matrix (steel sheet)
was applied to the Sn-plate steel sheet at intervals of 1 mm after the epoxy phenol resin
15 was baked, the tape peeling test was performed on the marking-off portions, and the
peeling resistance was estimated.
The results of the tape peeling test were generally estimated, the adhesiveness of
the coating material was estimated to be in one of four grades (A: peeling was not present
at all, B: slight peeling which was not a problem in practical use was present, C: slight
20 peeling was present, D: peeling was present over most thereof).
[0075]
As shown in Table 1, in Nos. 1 to 19 which satisfied the conditions according to
the present invention, the weldability, the film adhesiveness, and the corrosion resistance
were improved. On the other hand, in Nos. 20 to 25 which did not satisfy the conditions
25 according to the present invention, any of the weldability, the film adhesiveness, and the
corrosion resistance was deteriorated. Moreover, in No. 25 of Table 1, the Ni-plated
steel sheet on which the same PET film as the can body member was laminated was also
used with respect to the can bottom member. In No. 25, the formed portion such as the
screw portion or the flat sheet portion was corroded in the form of spots, and the amount
S -
5 of dissolved iron also increased. In addition, in cross-sectional observation of the
corroded areas, perforation corrosion proceeded. Particularly, in severely corroded
areas, it was confirmed that the perforation corrosion proceeded up to about 415 of the
sheet thickness. On the other hand, when the Sn-plated steel sheet on which the Sn
plating of sufficient amount was applied was used in the can bottom (can bottom
10 member), the corrosion was not observed at all. Even in the areas where the corrosion
was observed, the amount of the perforation corrosion was slight and was about 1/10 of
the sheet thickness at most. The adhesiveness of the coating material of Nos. 2, 4, 6, 8,
10, 12, 14, and 16 to 19 in which the chromate film was applied to the can bottom
member was higher compared to the adhesiveness of the coating material of Nos. 1, 3, 5,
15 7, 9, 11, 13, and 15 in which the chromate film was not applied to the can bottom
member. Thereby, when the coating material was coated on the can bottom, it was
confirmed that the can bottom member having the chromate film on the surface in which
the coating material was coated on the can bottom member (that is, surface which did not
contact acidic liquid, outer surface of the can main body) could be appropriately used.
20 100761
As shown in the above-described examples, it was obvious that the three-piece
resealable can according to the present invention had improved weldability, film
adhesiveness, and corrosion resistance and could store acidic liquid (acidic beverages)
with high quality.
[0077]
[Table 11
No.
metal Sn
chromate Weldabllity in screw dissolved material can bottom
resistance
formed iron on can member
P
P
* Underlines in this tabk indicate that the underlined ceUs do not satisfy conditiom according to the present invention
*1 Amount of alloyed Sn plating is equivalent to the amount in metal Sn
*2 Amount of chromate fihn is equivalent to the amount in chromium metal
Can body member
Manufacturing
Can bottom member
Amount
of
Ni Manufacturing
Estimation Results
Film
adhesiveness
Amount
of Sn
single
Amount
of
Ni
Amount
of
Amount
of
alloyed
mount
of Sn
single
Amount
of
chromate Corrosion
Amount
of
alloyed
Amount
of
Adhesiveness
of
coating
Appearance
of
100781
In addition, in order to further improve the corrosion resistance of the can body
member, the can main body was manufactured in which the resistance between the can
body member and the can bottom member was changed. For example, in order to
t .
5 decrease the resistance between the can body member and the can bottom member, in
Nos. 25 to 43 below, structure factors such as a method of seaming the can bottom
member to the can body member or material factors such as the amount of each layer of
the can body member and the can bottom member were changed.
[0079]
The Ni-plated steel sheet used in the can body member of No. 25 was
manufactured according to the following method (corresponding to the Manufacturing
Method 1). Ni plating was applied to both surfaces of a sheet to be plated (steel sheet)
which was subjected to annealing and skin pass after cold rolling and had a thickness of
0.19 mm, by applying a current of a current density of 1 ~ / d min a~ so lution of 45°C and
15 pH 4 including Ni ions of 40 glL using Ni sulfate and boric acid. Subsequently, by
performing chromate treatment with respect to both surfaces of the steel sheet through
cathode electrolysis at a current density of 5 Ndm2 in a solution of 100 g/L chromic acid
and 1 g/L sulfuric acid at 45OC, the Ni-plated steel sheet was manufactured. The
amount of Ni adhered to the steel sheet (the amount of Ni plating) was 500 mg/m2, and
20 the amount of chromate film was 5 mg/m2 expressed in terms of chromium metal.
The Sn-plated steel sheet used in the can bottom member (bottom cover) of No.
25 was manufactured according to the following method (corresponding to the
Manufacturing Method 4). Sn plating was applied to both surfaces of a sheet to be
plated (steel sheet) which was subjected to annealing and skin pass after cold rolling and
25 had a thickness of 0.19 mm, at 45OC and 2 Ndm2 in an Sn plating solution of pH 1.1
including Sn ions of 20 g/L prepared by using Sn sulfate and sulfuric acid, reflow and
chromate treatment were performed as necessary, and the Sn-plated steel was
manufactured. In the reflow, the steel sheet was cooled by 60°C water just after being
heated up to about 245°C through an electric heating method. In the chromate
t *
5 treatment, the cathode electrolysis was performed at a current density of 3 Ndm2 in a
solution of 40 g/L sodium dichromate at pH 4. The amount of Si adhered to the steel
sheet (the amount of Sn metal plating) was 11.2 g/m2, and the amount of chromate film
was 5 mg/m2 expressed in terms of chromium metal.
The Ni-plated steel sheet was cut down to a width of 170 mm. Next, the cut
10 Ni-plated steel sheet was heated to 1 80°C, a PET film (polyester resin film) of the
thickness of 12 pm having an adhesive layer was bonded by thermal compression to both
surfaces of the sheet except for the vicinity of the vertical edges which became the
portions to be welded, and the Ni-plated steel sheet in which the PET resin film was
laminated was manufactured. Moreover, the Ni-plated steel sheet was cut down to a
15 length of 11 0 mm (the size in a direction perpendicular to the width direction). At this
time, the Ni-plated steel sheet was cut so that the direction of the burr on the side (side
which becomes can end, sheet edge) on which the Ni-plated steel sheet and the bottom
cover are seamed became the outer surface direction of the can.
[0080]
20 As the steel sheet material of No. 26 (can body member and can bottom
member), a Ni-plated steel sheet which was manufactured similarly to No. 25 except for
the processing method (processing method of end surface) of the can end on one side,
and the same Sn-plated steel sheet as No. 25 were used. That is, in the processing
method of the end surface of the can body member, the PET resin film and the adhesive
25 layer, which were formed on the outer surface of Ni-plated steel sheet, were
mechanically removed using a grinder in an area having a width of 1 mm from the sheet
edge on the side (side which becomes can end) on which the bottom cover and the
Ni-plated steel sheet in which the PET resin film having a length of 110 mm and a width
of 170 mm was laminated were seamed.
[008 11
As the steel sheet material of No. 27 (can body member and can bottom
member), a Ni-plated steel sheet and an Sn-plated steel sheet, which were manufactured
similarly to No. 25 except for the processing method (processing method of end surface)
of the can end on one side, were used. That is, in the processing method of the end
10 surface of the can body member, the PET resin film and the adhesive layer, which were
formed on the outer surface of the Ni-plated steel sheet, were evaporated and removed
using a laser beam in an area having a width of 0.5 mm from the sheet edge on the side
(side which becomes can end) on which the bottom cover and the Ni-plated steel sheet in
which the PET resin film having a length of 110 mm and a width of 170 mm was
15 laminated were seamed.
[0082]
As the steel sheet material of NO. 28 (can body member and can bottom
member), a Ni-plated steel sheet (the same Ni-plate steel sheet as that of No. 27) which
was manufactured similarly to No. 25 except for the processing method (processing
20 method of end surface) of the can end on one side, and an Sn-plated steel sheet which
was manufactured similarly to No. 25 except for the amount of Sn plating were used.
That is, in the can bottom member, the amount of Sn plating (the amount of Sn metal
plating) was 5.6 g/m2, and the amount of chromate film was 5 mg/m2 expressed in terms
of chromium metal. In addition, in the processing method of the end surface of the can
25 body member, the PET resin film and the adhesive layer, which were formed on the outer
surface of the Ni-plated steel sheet, were evaporated and removed using a laser beam in
an area having a width of 0.5 mm from the sheet edge on the side (side which becomes
can end) on which the bottom cover and the Ni-plated steel sheet in which the PET resin
film having a length of 110 mm and a width of 170 mm was laminated were seamed.
f
[0083]
As the steel sheet material of No. 29 (can body member and can bottom
member), a Ni-plated steel sheet (the same Ni-plate steel sheet as that of No. 27) which
was manufactured similarly to No. 25 except for the processing method (processing
method of end surface) of the can end on one side, and an Sn-plated steel sheet which
10 was manufactured similarly to No. 25 except for the amount of Sn plating were used.
That is, in the can bottom member, the amount of Sn plating (the amount of Sn metal
plating) was 15.1 @m2, and the amount of chromate film was 5 mg/m2 expressed in terms
of chromium metal. In addition, in the processing method of the end surface of the can
body member, the PET resin film and the adhesive layer, which were formed on the outer
15 surface of the Ni-plated steel sheet, were evaporated and removed using a laser beam in
an area having a width of 0.5 mm from the sheet edge on the side (side which becomes
can end) on which the bottom cover and the Ni-plated steel sheet in which the PET resin
film having a length of 110 mm and a width of 170 mm was laminated were seamed.
[0084]
2 0 As the steel sheet material of No. 30 (can body member and can bottom
member), a Ni-plated steel sheet (the same Ni-plated steel sheet as that of No. 26) which
was manufactured similarly to No. 25 except for the processing method (processing
method of end surface) of the can end on one side, and an Sn-plated steel sheet which
was manufactured similarly to No. 25 except for the amount of Sn plating were used.
25 That is, in the can bottom member, the amount of Sn plating (the amount of Sn metal
49
plating) was 8.4 dm2, and the amount of chromate film was 5 mg/m2 expressed in terms
of chromium metal. In addition, in the processing method of the end surface of the can
body member, the PET resin film and the adhesive layer, which were formed on the outer
surface of the Ni-plated steel sheet, were mechanically removed using a grinder in an
7 -
5 area having a width of 1 mm from the sheet edge on the side (side which becomes can
end) on which the bottom cover and the Ni-plated steel sheet in which the PET resin film
having a length of 110 mm and a width of 170 mm was laminated were seamed.
[0085]
As the steel sheet material of No. 3 1 (can body member and can bottom
10 member), a Ni-plated steel sheet (the same Ni-plate steel sheet as that of No. 27) which
was manufactured similarly to No. 25 except for the processing method (processing
method of end surface) of the can end on one side, and an Sn-plated steel sheet which
was manufactured similarly to No. 25 except for the amount of chromate film were used.
That is, in the can bottom member, the amount of Sn plating (the amount of Sn metal
15 plating) was 11.2 g/m2, and the amount of chromate film was 3 mg/m2 expressed in terms
of chromium metal. In addition, in the processing method of the end surface of the can
body member, the PET resin film and the adhesive layer, which were formed on the outer
surface of the Ni-plated steel sheet, were evaporated and removed using a laser beam in
an area having a width of 0.5 mm from the sheet edge on the side (side which becomes
20 can end) on which the bottom cover and the Ni-plated steel sheet in which the PET resin
film having a length of 110 mm and a width of 170 mm was laminated were seamed.
[0086]
As the steel sheet material of No. 32 (can body member and can bottom
member), a Ni-plated steel sheet (the same Ni-plate steel sheet as that of No. 26) which
25 was manufactured similarly to No. 25 except for the processing method (processing
method of end surface) of the can end on one side, and an Sn-plated steel sheet which
was manufactured similarly to No. 25 except for the amount of chromate film were used.
That is, in the can bottom member, the amount of Sn plating (the amount of Sn metal
plating) was 11.2 g/m2, and the amount of chromate film was 8 mg/m2 expressed in terms
f *
5 of chromium metal. In addition, in the processing method of the end surface of the can
body member, the PET resin film and the adhesive layer, which were formed on the outer
surface of the Ni-plated steel sheet, were mechanically removed using a grinder in an
area having a width of 1 mm from the sheet edge on the side (side which becomes can
end) on which the bottom cover and the Ni-plated steel sheet in which the PET resin film
10 having a length of 110 mm and a width of 170 mm was laminated were seamed.
[0087]
As the steel sheet material of No. 33 (can body member and can bottom
member), a Ni-plated steel sheet which was manufactured similarly to No. 25 except for
the amount of Ni plating and the processing method (processing method of end surface)
15 of the can end on one side, and the same Sn-plated steel sheet as No. 25 were used.
That is, in the can body member, the amount of Ni plating was 260 mg/m2, and the
amount of chromate film was 5 mg/m2 expressed in terms of chromium metal. In
addition, in the processing method of the end surface of the can body member, the PET
resin film and the adhesive layer, which were formed on the outer surface of the
20 Ni-plated steel sheet, were evaporated and removed using a laser beam in an area having
a width of 0.5 mm from the sheet edge on the side (side which becomes can end) on
which the bottom cover and the Ni-plated steel sheet in which the PET resin film having
a length of 110 mm and a width of 170 mm was laminated were seamed.
[OOSS]
As the steel sheet material of No. 34 (can body member and can bottom
5 1
member), a Ni-plated steel sheet which was manufactured similarly to No. 25 except for
the amount of Ni plating and the processing method (processing method of end surface)
of the can end on one side, and the same Sn-plated steel as No. 25 were used. That is,
in the can body member, the amount of Ni plating was 950 mg/m2, and the amount of
t
5 chromate film was 5 mg/m2 expressed in terms of chromium metal. In addition, in the
processing method of the end surface of the can body member, the PET resin film and the
adhesive layer, which were formed on the outer surface of the Ni-plated steel sheet, were
mechanically removed using a grinder in an area having a width of 1 mm from the sheet
edge on the side (side which becomes can end) on which the bottom cover and the
10 Ni-plated steel sheet in which the PET resin film having a length of 110 mm and a width
of 170 mm was laminated were seamed.
[0089]
As the steel sheet material of No. 35 (can body member and can bottom
member), a Ni-plated steel sheet which was manufactured similarly to No. 25 except for
15 the amount of chromate film and the processing method (processing method of end
surface) of the can end on one side, and the same Sn-plated steel sheet as that of No. 25
were used. That is, in the can body member, the amount of Ni plating was 500 mg/m2,
and the amount of chromate film was 3 mg/m2 expressed in terms of chromium metal.
In addition, in the processing method of the end surface of the can body member, the
T
20 PET resin film and the adhesive layer, which were formed on the outer surface of the
Ni-plated steel sheet, were evaporated and removed using a laser beam in an area having
a width of 0.5 mm from the sheet edge on the side (side which becomes can end) on
which the bottom cover and the Ni-plated steel sheet in which the PET resin film having
a length of 110 mm and a width of 170 mm was laminated were seamed.
[0090]
As the steel sheet material of No. 36 (can body member and can bottom
member), a Ni-plated steel sheet which was manufactured similarly to No. 25 except for
the amount of chromate film and the processing method (processing method of end
surface) of the can end on one side, and the same Sn-plated steel sheet as that of No. 25
! -
5 were used. That is, in the can body member, the amount of Ni plating was 500 mg/m2,
and the amount of chromate film was 8 mg/m2 expressed in terms of chromium metal.
In addition, in the processing method of the end surface of the can body member, the
PET resin film and the adhesive layer, which were formed on the outer surface of the
Ni-plated steel sheet, were mechanically removed using a grinder in an area having a
10 width of 1 mm from the sheet edge on the side (side which becomes can end) on which
the bottom cover and the Ni-plated steel sheet in which the PET resin film having a
length of 110 mm and a width of 170 mm was laminated were seamed.
[009 11
As the steel sheet material of No. 37 (can body member and can bottom
15 member), a Ni-plated steel sheet which was manufactured similarly to No. 25 except for
the processing method (processing method of end surface) of the can end on one side,
and the same Sn-plated steel sheet as that of No. 25 were used. That is, in the
processing method of the end surface of the can body member, Ni-plated steel sheet in
which the PET resin film having a length of 110 mm and a width of 170 mm was
20 laminated was cut down so that the direction of the burr on the side (side which becomes
can end, sheet edge) on which the bottom cover and the Ni-plated steel sheet was seamed
became the direction of the inner surface of the can.
[0092]
As the steel sheet material of No. 38 (can body member and can bottom
25 member), a Ni-plated steel sheet (the same Ni-plated steel sheet as that of No. 26) which
was manufactured similarly to No. 25 except for the processing method (processing
method of end surface) of the can end on one side, and an Sn-plated steel sheet which
was manufactured similarly to No. 25 except for the amount of Sn plating were used.
That is, in the can bottom member, the amount of Sn plating (the amount of Sn metal
t .
5 plating) was 4. 7 g/m2, and the amount of chromate film was 5 mg/m2 expressed in terms
of chromium metal. In addition, in the processing method of the end surface of the can
body member, the PET resin film and the adhesive layer, which were formed on the outer
surface of Ni-plated steel sheet, were mechanically removed using a grinder in an area
having a width of 1 mm from the sheet edge on the side (side which becomes can end) on
10 which the bottom cover and the Ni-plated steel sheet in which the PET resin film having
a length of 11 0 mm and a width of 170 mm was laminated were seamed.
[0093]
As the steel sheet material of No. 39 (can body member and can bottom
member), a Ni-plated steel sheet (the same Ni-plated steel sheet as that of No. 26) which
15 was manufactured similarly to No. 25 except for the processing method (processing
method of end surface) of the can end on one side, and an Sn-plated steel sheet which
was manufactured similarly to No. 25 except for the amount of chromate film were used.
That is, in the can bottom member, the amount of Sn plating (the amount of Sn metal
plating) was 11.2 g/m2, and the amount of chromate film was 1 mg/m2 expressed in terms
20 of chromium metal. In addition, in the processing method of the end surface of the can
. body member, the PET resin film and the adhesive layer, which were formed on the outer
surface of Ni-plated steel sheet, were mechanically removed using a grinder in an area
having a width of 1 mm from the sheet edge on the side (side which becomes can end) on
which the bottom cover and the Ni-plated steel sheet in which the PET resin film having
25 a length of 110 mm and a width of 170 mm was laminated were seamed.
As the steel sheet material of No. 40 (can body member and can bottom
member), a Ni-plated steel sheet (the same Ni-plated steel sheet as that of No. 26) which
was manufactured similarly to No. 25 except for the processing method (processing
1( *
5 method of end surface) of the can end on one side, and an Sn-plated steel sheet which
was manufactured similarly to No. 25 except for the amount of chromate film were used.
That is, in the can bottom member, the amount of Sn plating (the amount of Sn metal
plating) was 11.2 g/m2, and the amount of chromate film was 12 mg/m2 expressed in
terms of chromium metal. In addition, in the processing method of the end surface of
10 the can body member, the PET resin film and the adhesive layer, which were formed on
the outer surface of Ni-plated steel sheet, were mechanically removed using a grinder in
an area having a width of 1 mm from the sheet edge on the side (side which becomes can
end) on which the bottom cover and the Ni-plated steel sheet in which the PET resin film
having a length of 110 mm and a width of 170 mm was laminated were seamed.
15 [0095]
As the steel sheet material of No. 41 (can body member and can bottom
member), a Ni-plated steel sheet which was manufactured similarly to No. 25 except for
the amount of Ni plating and the processing method (processing method of end surface)
of the can end on one side, and the same Sn-plated steel sheet as that of No. 25 were used.
20 That is, in the can body member, the amount of Ni plating was 150 mg/m2, and the
amount of chromate film was 5 mg/m2 expressed in terms of chromium metal. In
addition, in the processing method of the end surface of the can body member, the PET
resin film and the adhesive layer, which were formed on the outer surface of Ni-plated
steel sheet, were mechanically removed using a grinder in an area having a width of 1
25 mm from the sheet edge on the side (side which becomes can end) on which the bottom
cover and the Ni-plated steel sheet in which the PET resin film having a length of 110
mm and a width of 170 mm was laminated were seamed.
As the steel sheet material of No. 42 (can body member and can bottom
f
5 member), a Ni-plated steel sheet which was manufactured similarly to No. 25 except for
the amount of chromate film and the processing method (processing method of end
surface) of the can end on one side, and the same Sn-plated steel sheet as that of No. 25
were used. That is, in the can body member, the amount of Ni plating was 500 mg/m2,
and the amount of chromate film was 1 mg/m2 expressed in terms of chromium metal.
10 In addition, in the processing method of the end surface of the can body member, the
PET resin film and the adhesive layer, which were formed on the outer surface of
Ni-plated steel sheet, were mechanically removed using a grinder in an area having a
width of 1 mm from the sheet edge on the side (side which becomes can end) on which
the bottom cover and the Ni-plated steel sheet in which the PET resin film having a
15 length of 110 mm and a width of 170 mm was laminated were seamed.
100971
As the steel sheet material of No. 43 (can body member and can bottom
member), a Ni-plated steel sheet which was manufactured similarly to No. 25 except for
the amount of chromate film and the processing method (processing method of end
20 surface) of the can end on one side, and the same Sn-plated steel sheet as that of No. 25
were used. That is, in the can body member, the amount of Ni plating was 500 mg/m2,
and the amount of chromate film was 12 mg/m2 expressed in terms of chromium metal.
In addition, in the processing method of the end surface of the can body member, the
PET resin film and the adhesive layer, which were formed on the outer surface of
25 Ni-plated steel sheet, were mechanically removed using a grinder in an area having a
-
5 6
width of 1 mm from the sheet edge on the side (side which becomes can end) on which
the bottom cover and the Ni-plated steel sheet in which the PET resin film having a
length of 110 mm and a width of 170 mm was laminated were seamed.
[0098]
t *
In Nos. 25 to 43 described above, similarly to the estimation item (I), the
weldability was estimated with respect to the can body member (here, Ni-plated steel
sheet) using a welder of Soudronic AG Next, similarly to the estimation item (2), a
threading was performed on the can end on one side of the cylindrical can body member,
and the film adhesiveness of the formed portion was estimated. Moreover, similarly to
the estimation item (3), a cap made of aluminum was covered on the can end (screw
portion of can body member) subjected to the threading, and commercially available
100% orange juice (acidic beverages) was filled into the can body portion to which the
cap made of aluminum was attached. Thereafter, a cover forming was performed on the
Sn-plated steel sheet, and therefore, the can bottom member was manufactured.
Moreover, the can bottom member and the other can end (opening portion) of the can
body portion were seamed, and the corrosion resistance was estimated. In addition, in
the estimation of the corrosion resistance of the estimation item (3), the long-term
corrosion resistance of the can bottom member was also estimated. That is, after the
corrosion resistance test, the can bottom were observed, and the corrosion resistance of
the can bottom was estimated to be in one of four grades (A: corrosion was not observed,
B: slight corrosion which was not a problem in practical use was observed, C: slight
corrosion was observed, and D: severe corrosion was observed).
[0099]
In Nos. 25 to 43 of Table 2, the following estimation item (5) was estimated in
addition to the estimation items (1) to (3).
57
(5) Resistance Measurement
After the can bottom (bottom cover, can bottom member) and the can body (can
body member) were seamed, the organic film (PET resin film and adhesive layer) and the
chromate film of the outer surfaces of the can bottom and the can body were
Y -
5 mechanically removed, and the resistance was measured.
The estimation results are shown in Table 2 along with the manufacturing
conditions of the can (amount of Sn metal plating, amount of Ni plating, and amount of
chromate film). Moreover, overall estimation (determined by the lowest rating) with
10 respect to the estimation items (1) to (3) was also performed.
[OlOl]
As shown in Table 2, in all the can main bodies of Nos. 25 to 36, the weldability,
the appearance, the film adhesiveness of the screw formed portion, and the corrosion
resistance (resistance to filiform corrosion) were sufficient. Moreover, in all the can
15 main bodies of Nos. 37 to 40 and 43, the weldability, the appearance, the film
adhesiveness of the screw formed portion, and the corrosion resistance (resistance to
filiform corrosion) were of a level which was not a problem in practical use.
However, in the can main bodies of Nos. 25 to 36, since the resistance value
between the can body and the can bottom was smaller than that of the can main body of
20 No. 37, the corrosion resistance of the can body portion was higher than that of the can
main body of No. 37. In addition, in the can main bodies of Nos. 26,27,29 to 36, since
the resistance value between the can body and the can bottom was smaller than that of
the can main body of No. 25, the corrosion resistance of the can body portion was higher
than that of the can main body of No. 25.
25 Moreover, in the can main bodies of Nos. 25 to 36, since the amount of Sn
-
58
plating (amount of Sn metal plating) of the can bottom member was heavier than that of
the can main body of No. 38, the corrosion resistance of the can body portion was higher
than that of the can main body of No. 38. In addition, in the can main bodies of Nos. 26,
27,29 to 36, since the amount of Sn plating (amount of Sn metal plating) of the can
! *
5 bottom member was heavier than that of the can main body of No. 28, the corrosion
resistance of the can body portion was higher than that of the can main body of No. 28.
Moreover, in the can main bodies of Nos. 26,27, and 29 to 36, since the amount
of chromate film of the can bottom member and the can body member was more *
optimally controlled compared to the can main bodies of Nos. 39,40,42, and 43, any one
10 or more of the long-term corrosion resistance of the can bottom member, the corrosion
resistance, the film adhesiveness, and the weldability of the can body member were
further improved.
In the can main body of No. 41, since the amount of the metal plating in the
welding portion of the can body member was not sufficient, the weldability of the can
15 body member was not sufficient. In the can main body of No. 42, since the amount of
chromate film of the can body member was not sufficient, the film adhesiveness of the
screw formed portion of the can body member was not suflicient.
[O 1 021
[Table 21
* Underlines in this table indicate that the underlined cells do not satisfy conditions according to the present invention
* 1 Amount of chromate fh is equivalent to the amount in chromium metal
No
Estimation results
(mg/m2) (mg/m2) (mg/m2) ('1 after test member portion
Resistance
between
can body
and can
bottom
Weldabib
Can Can bottom member body member
42 1 11.2 1 5 1 500 1 - 1 1 0.04 1 A
Film
adhesiveness
in screw
formed
funount
of
Ni
plating
of Sn
metal
plating
Amount
of
chromate
film*'
Appearance
of
can bottom
member
Amount
of
chromate
film"
A
Corrosion
resistance
Long-term
corrosion
resistance
of can
bottom
Overall
rating
A
43 1 11.2 1 5 I 500 I 12 1 0.07 1 C
-
A
D
A A I C
C I D
A
containing Sn metal particles in the can body member shown in Nos. 44 to 63 of Table 3.
[0 1041
Moreover, a composition of the polyester resin film used in Nos. 44 to 63 was
the following.
t q
Film of Polyester Resin A: Mixture of 98 mass% polyethylene terephthalate and
2 mass% polyethylene terephthalate-polytetramethylene glycol ether block copolymer
(film A in Table 3)
Film of Polyester Resin B: Mixture of 95 mass% polyethylene terephthalate and
5 mass% poly-(ethylene glycol-neopentyl glycol-cyclohexane dimethanol) ester
10 copolymer (film B in Table 3).
Film of Polyester Resin C: Mixture of 90 mass% polyethylene terephthalate and
10 mass% polyethylene terephthalate-polyethylene glycol ether random copolymer (PEG
(polyethylene glycol) content 2 mol %) (film C in Table 3).
Moreover, as the adhesive (adhesive layer) used in Nos. 44 to 63, polyester
15 which was a thermoplastic resin (adhesive resin I in Table 3) and polyester-epoxy and
blocked isocyanate curing agent which were a thermosetting resin (adhesive resin I1 in
Table 3) were used.
[0105]
The polyester resin film and the adhesive layer used in the can body member of
20 No. 44 were manufactured according to the following method. After the thermoplastic
resin (polyester resin) in which Sn metal particles having a mean particle diameter of 2.4
pm were dispersed was coated on one surface of the film of the polyester resin A having
a thickness of 12 pm, the surface was dried, and a film 1 of the polyester resin A was
manufactured. The amount of Sn metal particles was 1500 mg/m2, and the mean coated
,25 film thickness at five points of the adhesive layer was 5 pm. In addition, after the
thermosetting resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn
metal particles were not contained was coated on one surface of the film of the polyester
resin A having a thickness of 12 pm, the surface was dried, and a film 0 of the polyester
resin A was manufactured. The mean coated film thickness at five points of the
1, *
5 adhesive layer was 5 pm.
The Ni-plated steel sheet used in the can body member of No. 44 was
manufactured according to the following method (corresponding to the Manufacturing
Method 1). Ni plating was applied to both surfaces of a sheet to be plated (steel sheet)
which was subjected to annealing and skin pass after cold rolling and had a thickness of
10 0.19 mm, by applying a current of a current density of 1 ~ / d min a~ so lution of 45°C and
pH 4 including Ni ions of 40 g/L using Ni sulfate and boric acid. Subsequently, by
performing chromate treatment with respect to both surfaces of the steel sheet through
cathode electrolysis at a current density of 5 Ndm2 in a solution of 100 g/L chromic acid
and 1 g/L sulfuric acid at 45"C, the Ni-plated steel sheet was manufactured. The
15 amount of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2
expressed in terms of Cr metal.
The Ni-plated steel sheet was cut down to a length of 110 mm and a width of
170 mm, subsequently, the cut steel sheet was heated to 1 80°C, thereafter, the film 1 of
the polyester resin A was bonded to one surface by thermal compression and the film 0 of
20 the polyester resin A was bonded to the other surface by thermal compression so that the
adhesive layer contacted the surface of the steel sheet except for the vicinity of the
vertical edges which becomes the portions to be welded, and the Ni-plated steel sheet
(resin film laminated steel sheet 1) for the can body member was manufactured.
[0 1061
-
62
The polyester resin film and the adhesive layer used in the can body member of
No. 45 were manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 6.6 pm were dispersed was coated on one
' I *
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 2 of the polyester resin A was manufactured. The amount of Sn metal
particles was 1500 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 12
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. A
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 45 (can body member and the can bottom
member), the Ni-plated steel sheet similar to that of No. 44 was used. That is, the
amount of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2
expressed in terms of Cr metal.
The steel sheet material having a length of 110 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 2 of the polyester resin A was bonded to one surface
by thermal compression and the film 0 of the polyester resin A was bonded to the other
surface by thermal compression so that the adhesive layer contacted the surface of the
steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 2) for the can
body member was manufactured.
[0 1 071
The polyester resin film and the adhesive layer used in the can body member of
63
No. 46 were manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 3.5 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
t '8
5 dried, and a film 3 of the polyester resin A was manufactured. The amount of Sn metal
particles was 1500 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the PET film having a thickness of 20 pm, the surface was
10 dried, and a film 0 of the polyester resin A was manufactured. The mean coated film
thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 46 (can body member and the can bottom
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
15 terms of Cr metal.
The steel sheet material having a length of 110 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 3 of the polyester resin A was bonded to one surface
by thermal compression and the film 0 of the polyester resin A was bonded to the other
surface by thermal compression so that the adhesive layer contacted the surface of the
20 steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 3) for the can
body member was manufactured.
[O 1 081
The polyester resin film and the adhesive layer used in the can body member of
No. 47 were manufactured according to the following method. After the thermosetting
64
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 5.5 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 4 of the polyester resin A was manufactured. The amount of Sn metal
YI *
5 particles was 1500 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. A
10 mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 47 (can body member and the can bottom
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
terms of Cr metal.
15 The steel sheet material having a length of 11 0 mm and a width of 170 mm was
heated to 180°C, thereafter, the film 4 of the polyester resin A was bonded to one surface
by thermal compression and the film 0 of the polyester resin A was bonded to the other
surface by thermal compression so that the adhesive layer contacted the surface of the
steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 4) for the can
20 body member was manufactured.
[0 1091
The polyester resin film and the adhesive layer used in the can body member of
No. 48 were manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 5 of the polyester resin A was manufactured. The amount of Sn metal
particles was 200 mg/m2, and the mean coated film thickness at five points of the r -
5 adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
10 As the steel sheet material of No. 48 (can body member and the can bottom
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
terms of Cr metal.
The steel sheet material having a length of 110 mm and a width of 170 mm was
15 heated to 1 80°C, thereafter, the film 5 of the polyester resin A was bonded to one surface
by thermal compression and the film 0 of the polyester resin A was bonded to the other
surface by thermal compression so that the adhesive layer contacted the surface of the
steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 5) for the can
body member was manufactured.
20 [OllO]
The polyester resin film and the adhesive layer used in the can body member of
No. 49 were manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 6 of the polyester resin A was manufactured. The amount of Sn metal
particles was 3400 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
f -
5 resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 49 (can body member and the can bottom
10 member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
of Ni plating was 500 mg/m2 and the amount of the chromate film was 5 mg/m2
expressed in terms of Cr metal.
The steel sheet material having a length of 11 0 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 6 of the polyester resin A was bonded to one surface
15 by thermal compression and the film 0 of the polyester resin A was bonded to the other
surface by thermal compression so that the adhesive layer contacted the surface of the
steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 6) for the can
body member was manufactured.
[Olll]
2 0 The polyester resin film and the adhesive layer used in the can body member of
No. 50 were manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
67
dried, and a film 7 of the polyester resin A was manufactured. The amount of Sn metal
particles was 400 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
'i, .
5 was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 50 (can body member and the can bottom
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
10 of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
terms of Cr metal.
The steel sheet material having a length of 11 0 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 7 of the polyester resin A was bonded to one surface
by thermal compression and the film 0 of the polyester resin A was bonded to the other
15 surface by thermal compression so that the adhesive layer contacted the surface of the
steel sheet, electron beams were radiated on the surface of the film 7 of the polyester
resin A by 3.5 Mrad, and the Ni-plated steel sheet (resin film laminated steel sheet 7) for
the can body member was manufactured.
[0112]
20 The polyester resin film and the adhesive layer used in the can body member of
No. 5 1 was manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
68
dried, and a film 8 of the polyester resin A was manufactured. The amount of Sn metal
particles was 1800 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
? *
5 was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 5 1 (can body member and the can bottom
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
10 of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
terms of Cr metal.
The steel sheet material having a length of 110 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 8 of the polyester resin A was bonded to one surface
by thermal compression and the film 0 of the polyester resin A was bonded to the other
15 surface by thermal compression so that the adhesive layer contacted the surface of the
steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 8) for the can
body member was manufactured.
[0113]
The polyester resin film and the adhesive layer used in the can body member of
20 No. 52 was manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 9 of the polyester resin A was manufactured. The amount of Sn metal
69
particles was 1 500 mg/rn2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
i ,-
5 pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 52 (can body member and the can bottom
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
10 terms of Cr metal.
The steel sheet material having a length of 110 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 9 of the polyester resin A was bonded to one surface
by thermal compression and the film 0 of the polyester resin A was bonded to the other
surface by thermal compression so that the adhesive layer contacted the surface of the
15 steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 9) for the can
body member was manufactured.
[0114]
The polyester resin film and the adhesive layer used in the can body member of
No. 53 was manufactured according to the following method. After the thermosetting
20 resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 10 of the polyester resin A was manufactured. The amount of Sn metal
particles was 1500 mglm2, and the mean coated film thickness at five points of the
adhesive. layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
t .
5 mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 53 (can body member and the can bottom
member), a Ni-plated steel sheet manufactured similarly to that of No. 44 except for the
amount of Ni plating was used. The amount of Ni plating was 260 rng/m2 and the
amount of chromate film was 5 mg/m2 expressed in terms of Cr metal.
10 The steel sheet material having a length of 110 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 10 of the polyester resin A was bonded to one
surface by thermal compression and the film 0 of the polyester resin A was bonded to the
other surface by thermal compression so that the adhesive layer contacted the surface of
the steel sheet, and a Ni-plated steel sheet (resin film laminated steel sheet 10) for the can
15 body member was manufactured.
[0115]
The polyester resin film and the adhesive layer used in the can body member of
No. 54 were manufactured according to the following method. Afier the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
20 particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 11 of the polyester resin A was manufactured. The amount of Sn metal
particles was 1500 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
S *
As the steel sheet material of No. 54 (can body member and the can bottom
member), a Ni-plated steel sheet manufactured similarly to that of No. 44 except for the
amount of Ni plating was used. The amount of Ni plating was 950 mg/m2 and the
amount of chromate film was 5 mg/m2 expressed in terms of Cr metal.
The steel sheet material having a length of 110 mm and a width of 170 mm was
10 heated to 1 80°C, thereafter, the film 11 of the polyester resin A was bonded to one
surface by thermal compression and the film 0 of the polyester resin A was bonded to the
other surface by thermal compression so that the adhesive layer contacted the surface of
the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 11) for the
can body member was manufactured.
15 [0116]
The polyester resin film and the adhesive layer used in the can body member of
No. 55 were manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
20 surface of the film of the polyester resin B having a thickness of 12 pm, the surface was
dried, and a film 12 of the polyester resin B was manufactured. The amount of Sn
1
metal particles was 1500 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin B having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin B was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 55 (can body member and the can bottom
Y q
5 member), a Ni-plated steel sheet manufactured similarly to that of No. 44 except for the
amount of chromate film was used. The amount of Ni plating was 500 mg/m2 and the
amount of chromate film was 3 mg/m2 expressed in terms of Cr metal.
The steel sheet material having a length of 11 0 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 12 of the polyester resin B was bonded to one
10 surface by thermal compression and the film 0 of the polyester resin B was bonded to the
other surface by thermal compression so that the adhesive layer contacted the surface of
the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 12) for the
can body member was manufactured.
[0117]
15 The polyester resin film and the adhesive layer used in the can body member of
No. 56 was manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin C having a thickness of 12 pm, the surface was
20 dried, and a film 13 of the polyester resin C was manufactured. The amount of Sn
metal particles was 1500 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin C having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin C was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 56 (can body member and the can bottom
member), a Ni-plated steel sheet manufactured similarly to that of No. 44 except for the
t .
5 amount of chromate film was used. The amount of Ni plating was 500 mg/m2 and the
amount of chromate film was 8 mg/m2 expressed in terms of Cr metal.
The steel sheet material having a length of 11 0 mm and a width of 170 mm was
heated to 180°C, thereafter, the film 13 of the polyester resin C was bonded to one
surface by thermal compression and the film 0 of the polyester resin C was bonded to the
10 other surface by thermal compression so that the adhesive layer contacted the surface of
the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 13) for the
can body member was manufactured.
[0118]
The polyester resin film and the adhesive layer used in the can body member of
15 No. 57 was manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 1.5 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 2 1 of the polyester resin A was manufactured. The amount of Sn metal
20 particles was 1500 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 57 (can body member and the can bottom
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
f ,.
5 terms of Cr metal.
The steel sheet material having a length of 11 0 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 21 of the polyester resin A was bonded to one
surface by thermal compression and the film 0 of the polyester resin A was bonded to the
other surface by thermal compression so that the adhesive layer contacted the surface of
10 the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 21) for the
can body member was manufactured.
The polyester resin film and the adhesive layer used in the can body member of
No. 58 was manufactured according to the following method. After the thermosetting
15 resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 8.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 22 of the polyester resin A was manufactured. The amount of Sn metal
particles was 1500 mg/m2, and the mean coated film thickness at five points of the
20 adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 58 (can body member and the can bottom
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
terms of Cr metal.
7 ,.
The steel sheet material having a length of 11 0 mm and a width of 170 mm was
heated to 180°C, thereafter, the film 22 of the polyester resin A was bonded to one
surface by thermal compression and the film 0 of the polyester resin A was bonded to the
other surface by thermal compression so that the adhesive layer contacted the surface of
the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 22) for the
10 can body member was manufactured.
[O 1201
The polyester resin film and the adhesive layer used in the can body member of
No. 59 were manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
15 particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 23 of the polyester resin A was manufactured. The amount of Sn metal
particles was 50 mg/m2, and the mean coated film thickness at five points of the adhesive
layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy resin,
20 blocked isocyanate curing agent) in which Sn metal particles were not contained was
coated on one surface of the film of the polyester resin A having a thickness of 20 pm,
the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the'adhesive layer was 5 pm.
As the steel sheet material of No. 59 (can body member and the can bottom
76
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
terms of Cr metal.
The steel sheet material having a length of 11 0 mm and a width of 170 mm was
t .
5 heated to 1 80°C, thereafter, the film 23 of the polyester resin A was bonded to one
surface by thermal compression and the film 0 of the polyester resin A was bonded to the
other surface by thermal compression so that the adhesive layer contacted the surface of
the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 23) for the
can body member was manufactured.
[0121]
The polyester resin film and the adhesive layer used in the can body member of
No. 60 was manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
15 surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 24 of the polyester resin A was manufactured. The amount of Sn metal
particles was 4000 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
20 was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 60 (can body member and the can bottom
member), a Ni-plated steel sheet similar to that of No. 44 was used. That is, the amount
77
of Ni plating was 500 mg/m2 and the amount of chromate film was 5 mg/m2 expressed in
terms of Cr metal.
The steel sheet material having a length of 11 0 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 24 of the polyester resin A was bonded to one
T *
5 surface by thermal compression and the film 0 of the polyester resin A was bonded to the
other surface by thermal compression so that the adhesive layer contacted the surface of
the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 24) for the
can body member was manufactured.
[O 1221
The polyester resin film and the adhesive layer used in the can body member of
No. 61 were manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
15 dried, and a film 25 of the polyester resin A was manufactured. The amount of Sn metal
particles was 1500 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
20 pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 61 (can body member and the can bottom
member), a Ni-plated steel sheet manufactured similarly to that of No. 44 except for the
amount of Ni plating was used. The amount of Ni plating was 150 mg/m2 and the
amount of chromate film was 5 mg/m2 expressed in terms of Cr metal.
The steel sheet material having a length of 1 I0 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 25 of the polyester resin A was bonded to one
surface by thermal compression and the film 0 of the polyester resin A was bonded to the
3
5 other surface by thermal compression so that the adhesive layer contacted the surface of
the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 25) for the
can body member was manufactured.
[0 1231
The polyester resin film and the adhesive layer used in the can body member of
10 No. 62 were manufactured according to the following method. After the thermosetting
resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 26 of the polyester resin A was manufactured. The amount of Sn metal
15 particles was 1500 mg/m2, and the mean coated film thickness at five points of the
adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
20 mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 62 (can body member and the can bottom
member), a Ni-plated steel sheet manufactured similarly to that of No. 44 except for the
amount of chromate film was used. The amount of Ni plating was 500 mg/m2 and the
amount of chromate film was 1 mg/m2 expressed in terms of Cr metal.
The steel sheet material having a length of 110 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 26 of the polyester resin A was bonded to one
surface by thermal compression and the film 0 of the polyester resin A was bonded to the
other surface by thermal compression so that the adhesive layer contacted the surface of
? -
5 the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 26) for the
can body member was manufactured.
[0 1 241
The polyester resin film and the adhesive layer used in the can body member of
No. 63 were manufactured according to the following method. After the thermosetting
10 resin (polyester-epoxy resin, blocked isocyanate curing agent) in which Sn metal
particles having a mean particle diameter of 4.0 pm were dispersed was coated on one
surface of the film of the polyester resin A having a thickness of 12 pm, the surface was
dried, and a film 27 of the polyester resin A was manufactured. The amount of Sn metal
particles was 1500 mg/m2, and the mean coated film thickness at five points of the
15 adhesive layer was 5 pm. In addition, after the thermosetting resin (polyester-epoxy
resin, blocked isocyanate curing agent) in which Sn metal particles were not contained
was coated on one surface of the film of the polyester resin A having a thickness of 20
pm, the surface was dried, and a film 0 of the polyester resin A was manufactured. The
mean coated film thickness at five points of the adhesive layer was 5 pm.
As the steel sheet material of No. 63 (can body member and the can bottom
member), a Ni-plated steel sheet manufactured similarly to that of No. 44 except for the
amount of chromate film was used. The amount of Ni plating was 500 mg/m2 and the
amount of chromate film was 12 mg/m2 expressed in terms of Cr metal.
The steel sheet material having a length of 110 mm and a width of 170 mm was
heated to 1 80°C, thereafter, the film 27 of the polyester resin A was bonded to one
surface by thermal compression and the film 0 of the polyester resin A was bonded to the
other surface by thermal compression so that the adhesive layer contacted the surface of
the steel sheet, and the Ni-plated steel sheet (resin film laminated steel sheet 27) for the
t .
5 can body member was manufactured.
In Nos. 44 to 63, the following estimation item (6) was also estimated in
addition to the estimation items (1) to (3).
Moreover, in order to accurately estimate the corrosion resistance, as the can
10 bottom member, an Sn-plated steel sheet was used in which Ni plating was applied to the
steel sheet surface, Sn plating was applied to the Ni-plating surface, and electrolytic
chromic acid treatment was performed on the Sn-plating surface of, and the item (3) of
the estimation method was estimated. In the Sn-plated steel sheet, the amount of Ni
plating was 50 mg/m2, the amount of Sn metal plating was 1000 mg/m2, the amount of Cr
15 metal was 10 mg/m2, and the amount of hydrated chromium oxide expressed in terms of
Cr metal was 7 mg/m2. In this case, the corrosion resistance of only the can body
member can be ascertained, and the corrosion resistance of the can body member over
the longer term can be understood in as short a time as possible.
[0 1261
(6) Color Measurement (Film Appearance)
Colors of the manufactured various polyester resin film laminated-steel sheets
(steel sheet of can body member) were measured by a micro spectrophotometer VSS 400
manufactured by Nippon Denshoku Industries Co., Ltd. The range of the measured area
was set to cp 0.5 mm.
Compared to L value (film appearance) of a case where the Sn metal particles
were not contained, the case where a decrease in the L value was less than 2 was
evaluated as "A (good)", the case where a decrease in the L value was equal to or more
than 2 and less than 5 was evaluated as "B (usable in practice), and the case where a
decrease in the L value was more than 5 was evaluated as "C (difficult to be used in
7 '
5 practice when good film appearance is required)".
[0 1271
The estimation results are shown in Table 3 along with the manufacturing
conditions of the can (polyester film, adhesive layer, Sn metal particles, amount of Ni
plating, and amount of chromate film). Moreover, overall estimation (determined by
10 the lowest estimation) with respect to the estimation items (1) to (3) and (6) was also
performed.
[0128]
As shown in Table 3, in all the can main bodies of Nos. 44 to 56, the weldability,
the appearance, the film adhesiveness of the screw formed portion, and the corrosion
15 resistance (resistance to filiform corrosion) were sufficient. Moreover, in all the can
main bodies of Nos. 57 to 60 and 63, the weldability, the appearance, the film
adhesiveness of the screw formed portion, and the corrosion resistance (resistance to
filiform corrosion) were of a level which was not a problem in practical use.
However, in the can main bodies of Nos. 44 to 56, since the mean particle
20 diameter of the Sn metal particles was controlled to be 2 pm or more, the corrosion
resistance of the can body portion and the film appearance (film brightness) were more
improved compared to the can main body of No. 57. Particularly, in the can main
bodies of Nos. 45 to 46 and 50 to 56, since the mean particle diameter of the Sn metal
particles was controlled to be 3 pm or more, the corrosion resistance of the can body
25 portion and the film appearance (film brightness) were further improved compared to the
can main body of No. 44.
Moreover, in the can main bodies of Nos. 44 to 56, since the mean particle
diameter of the Sn metal particles was controlled to be 7 pm or less, the film
adhesiveness of the screw formed portion and the film appearance (film brightness) were
?
5 fhrther improved compared to the can main body of No. 58. Particularly, in the can
main bodies of Nos. 45 to 46 and 50 to 56, since the mean particle diameter of the Sn
metal particles was controlled to be 6 pm or less, the film adhesiveness of the screw
formed portion was further improved compared to the can main body of No. 44.
In addition, in the can main bodies of Nos. 44 to 56, since the amount of the Sn
10 metal particles in the adhesive layer was controlled to be 100 mg/m2 or more, the film
adhesiveness of the screw formed portion and the film appearance (film brightness) were
further improved compared to the can main body of No. 59. Particularly, in the can
main bodies of Nos. 45 to 46 and 50 to 56, since the amount of the Sn metal particles in
the adhesive layer was controlled to be 300 mg/m2 or more, the corrosion resistance of
15 the can body portion was further improved compared to the can main body of No. 48.
In addition, in the can main bodies of Nos. 44 to 56, since the amount of the Sn
metal particles in the adhesive layer was controlled to be 3600 mg/m2 or less, the film
appearance (film brightness) and the film adhesiveness of the screw formed portion were
further improved compared to the can main body of No. 60. Particularly, in the can
20 main bodies of Nos. 45 to 46 and 50 to 56, since the amount of the Sn metal particles in
the adhesive layer was controlled to be 2000 mg/m2 or more, the corrosion resistance of
the can body portion was further improved compared to the can main body of No. 49.
Moreover, in the can main bodies of Nos. 44 to 56, since the amount of
chromate film of the can body member was more suitably controlled, the weldability of
25 the can body member was further improved compared to the can main body of No. 63.
8 3
In this way, in the can main bodies of Nos. 45, 46, and 50 to 56 having a mean
particle diameter and an amount of the Sn metal particles in the preferable range, all
estimation items were improved.
[0 1291
t *
In the can main body of No. 61, since the amount of metal plating in the welding
portion of the can body member was not sufficient, the weldability of the can body
member was not sufficient. In the can main body of No. 62, since the amount of
chromate film of the can body member was not sufficient, the film adhesiveness of the
screw formed portion and the corrosion resistance of the can body member were not
10 sufficient.
[Table 31
[0131]
Therefore, it is considered that the can main bodies, which are improved in the
estimation items (1) to (3), can be obtained when the can body members of Nos. 44 to 60
5 and 63 and the can bottom member which is manufactured from the Sn-plated steel sheet
prepared according to any one of the manufacturing methods 4 to 6 are combined.
[0 1 321
As described above, the preferred embodiments of the present invention are
described. However, the present invention is not limited to the embodiments. It is
r *
5 obvious that various modifications or alterations can be conceived within the scope
described in claims by a person skilled in the art, and the modifications and the
alternations are also included in the technical scope of the present invention.
Industrial Applicability
[0133]
According to the present invention, the three-piece resealable can which has
improved film adhesiveness and corrosion resistance and can store acidic liquid,
particularly, acidic beverages such as fruit juice with high quality can be provided.
15 Reference Symbol List
[0 1341
1 : three-piece resealable can (can; resealable can)
2 (2A to 2F): can body member (can body; can body portion)
3 (3A to 35): can bottom member (can bottom; can bottom portion; bottom
20 cover; can cover)
4: cap
5: can main body
2 1 : screw portion (screw formed portion)
22: welding portion
23: polyester film (organic film, PET film)
24: chromate film
25: Ni plating
26: steel sheet (sheet to be plated)
27: Sn plating
5 27A: Sn single metal plating (non-alloyed Sn plating)
27B: alloyed Sn plating
28: adhesive layer
28A: Sn metal particles
34: chromate film
10 35: Ni plating
36: steel sheet (sheet to be plated)
37: Sn plating
37A: Sn single metal plating (non-alloyed Sn plating)
37B: alloyed Sn plating
15

What is claimed is:
1. A three-piece resealable can for acidic liquid, comprising:
a cylindrical can body member that includes a screw portion at one end; and
'1 ;
a can bottom member that contacts the can body member so as to close an
opening portion of the other end of the can body member,
wherein the can body member includes
a cylindrical first steel sheet,
a Ni plating that is formed on an inner circumferential surface of the first steel
10 sheet,
a polyester film that is formed so as to be disposed on an outermost surface of an
inner circumference of the can body member, and
a chromate film that is formed between the first steel sheet and the polyester
film, wherein
15 an amount of the Ni plating is 10 to 1000 mg/m2, an amount of the chromate
film is 2 to 30 mg/m2 expressed in terms of Cr metal, and an amount of a metal plating
which is closest to the outermost surface of the inner circumference of the can body
member is 200 to 4000 mg/m2, wherein
the can bottom member includes
a second steel sheet, and
an Sn plating that is formed on the can body member side of the can bottom
member, the Sn plating being on or above the second steel sheet, and wherein
the Sn plating includes an Sn single metal plating in an amount of 2 to 20 g/m2.
25 2. The three-piece resealable can for acidic liquid according to claim 1,
wherein an outermost surface on the can bottom member is the Sn plating
formed on the can body member side.
3. The three-piece resealable can for acidic liquid according to claim 1,
t ,-
wherein the can bottom member further includes a chromate film which is
formed on a surface of the Sn plating, an amount of the chromate film being 2 to 10
mg/m2 expressed in terms of Cr metal, and an outermost surface of the can bottom
member being the chromate film.
10 4. The three-piece resealable can for acidic liquid according to claim I,
wherein the Sn plating includes an alloyed Sn plating in an amount of 0.2 to 1.5
g/m2.
5. The three-piece resealable can for acidic liquid according to claim 1,
15 wherein th'e can bottom member further includes a Ni plating in an amount of 10
to 200 mg/m2 which is formed on a surface on the can body member side of the second
steel sheet.
6. The three-piece resealable can for acidic liquid according to claim 1,
20 wherein the amount of Sn single metal plating is 8 to 16 g/m2.
7. The three-piece resealable can for acidic liquid according to claim 1,
wherein the amount of the Ni plating is 200 to 1000 mg/m2 and the amount of
the chromate film is 2 to 10 mg/m2 expressed in terms of Cr metal.
8. The three-piece resealable can for acidic liquid according to claim 1,
wherein the can body member further includes an Sn plating which is formed on
a surface of the Ni plating, the Sn plating including an Sn single metal plating in 0.2 to 2
jj/m2 and an alloyed Sn plating, the amount of the Ni plating being 10 to 200 mg/m2, and
: *
5 the amount of the chromate film being 10 to 30 mg/m2.
9. The three-piece resealable can for acidic liquid according to claim 1,
wherein the can body member further includes an adhesive layer between the
chromate film and the polyester film.
10. The three-piece resealable can for acidic liquid according to claim 9,
wherein the adhesive layer contains 100 to 3600 mg/m2 of Sn metal particles
having a mean particle diameter of 2 to 7 pm with respect to a surface area of the first
steel sheet.
11. The three-piece resealable can for acidic liquid according to claim 10,
wherein the mean particle diameter of the Sn metal particles is 3 to 6 pm.
12. The three-piece resealable can for acidic liquid according to claim 10,
20 wherein the adhesive layer contains 300 to 2000 mg/m2 of the Sn metal particles
with respect to the surface area of the first steel sheet.
13. The three-piece resealable can for acidic liquid according to claim 1,
wherein a resistance between the can body member and the can bottom member
25 is 1 R or less.
14. The three-piece resealable can for acidic liquid according to claim 13,
wherein the resistance between the can body member and the can bottom
member is 0.1 i2 or less.