DESCRIPTION
TITLE OF INVENTION: ELECTRICAL STEEL SHEET AND METHOD
FOR MANUFACTURING THE SAME
TECHNICAL FIELD
[0001] The present invention relates to an
electrical steel sheet suitable for a material of an
iron core of an electric equipment and so on and a
method for manufacturing the same.
BACKGROUND ART
[0002] When a motor and a transformer are
manufactured by using an electrical steel sheet, the
electrical steel sheet in a hoop shape is punched
into a predetermined shape, and thereafter,
electrical steel sheets are laminated and fixed so as
to manufacture a laminated iron core. Thereafter, a
copper wire is wound around teeth or the like of the
laminated iron core. Then, there is a case when a
resin molding is performed aiming for improvement of
durability, weather resistance, and so on according
to usages thereof.
[0003] It is important to closely adhere a molding
resin to the laminated iron core. This is because
objects such as the improvement in durability and
weather resistance cannot be attained if the mold2ng
resin does not closely adhere to the laminated iron
core. Besides, in a motor using a magnet, the magnet
is fixed to the motor by using the molding resin, but
the fixing of the magnet becomes insufficient if the
adhesiveness is low.
[0004] On the other hand, it turns out that various
problems occur during a manufacturing process of the
motor and so on when the adhesiveness between the
molding resin and the laminated iron core is too
high. For example, in a motor and so on used for a
vehicle, there is a case when a compressive stress
acts on the laminated iron core from the molding
resin, and iron loss increases. In other words, if
the molding resin and an exposed part of the
laminated iron core are adhered in a case where the
resin molding has been performed after a conductive
part such as a coil is attached to the laminated iron
core, there is a case where the compressive stress
from the molding resin acts on the laminated iron
core and performance of the motor is lowered caused
by deterioration of the iron loss. Besides, when the
magnet is fixed to the motor with the molding resin,
it is difficult to remove the molding resin adhered
to unnecessary portions if the adhesiveness between
the molding resin and the laminated iron core is too
high.
CITATION LIST
PATENT LITERATURE
[0005] Patent Literature 1: Japanese Examined Patent
Application Publication No. 50-15013
Patent Literature 2: Japanese Laid-open Patent
Publication No. 03-36284
Patent Literature 3: Japanese Examined Patent
Application Publication No. 49-19078
Patent Literature 4: Japanese Laid-open Patent
Publication No. 06-330338
Patent Literature 5: Japanese Laid-open Patent
Publication No. 09-323066
Patent Literature 6: Japanese Laid-open Patent
Publication No. 2002-309379
Patent Literature 7: Japanese Laid-open Patent
Publication No. 2002-164207
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0006] An object of the present invention is to
provide an electrical steel sheet capable of
improving removability of a molding resin, and a
method for manufacturing the same.
SOLUTION TO PROBLEM
[0007] The present inventors studied about factors
deteriorating the removability of the molding resin,
and as a result, they found that adhesiveness between
an insulating film provided at a surface of an
electrical steel sheet and the molding resin is
excessively high. The insulating film is provided
mainly to secure insulating properties between the
laminated electrical steel sheets. Besides, there is
a case when various properties such as corrosion
resistance, weldability, adhesiveness, heat
resistance are required for the insulating film in
addition to the insulation performance. In general,
a mixture of which major constituents are inorganic
acid salts such as chromate and phosphate, and an
organic resin is coated to form the insulating film.
Various technologies are known as for the insulating
film of the electrical steel sheet. In recent years,
development of an insulating film has been advanced
in which a chromic acid solution containing
hexavalent chromium is not used from raising
consciousness on environmental problems.
[0008] However, in a conventional insulating film,
the removability of the molding resin is not focused
even if the properties such as the insulation
performance are sufficient, and there are various
problems in accordance with the lowness of the
removability of the molding resin as stated above.
The present inventors studied hard to solve the
above-stated problems, and as a result, they thought
out the following aspects.
[0009] (1) An electrical steel sheet, including:
a base iron; and
an insulating film formed on a surface of the
base iron,
wherein the insulating film contains:
I a first component: 100 parts by mass, the first
component containing:
a metal phosphate: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 pm
to 0.50 pm, or a mixture or copolymer of two or three
kinds selected from the group: 1 part by mass to 50
parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 pm to 0.35 pm: 0.5 parts by mass to 10
parts by mass.
[0010] (2) An electrical steel sheet, including:
a base iron; and
an insulating film formed on a surface of the
base iron,
wherein the insulating film contains:
a first component: 100 parts by mass, the first
component containing:
a colloidal silica: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 pm
to 0.50 pm, or a mixture or copolymer of two or three
kinds selected from the group: 40 parts by mass to
400 parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 pm to 0.35 pm: 0.5 parts by mass to 10
parts by mass.
[00111 (3) The electrical steel sheet according to
(1) or (2), wherein the first component and the
second component account for 90% or more of the
insulating film.
[0012] (4) A method for manufacturing an electrical
steel sheet, including:
- applying a treatment solution on a surface of a
base iron; and
baking and drying the treatment solution,
wherein the treatment solution contains:
a first component: 100 parts by mass in solid
content, the first component containing:
a metal phosphate: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an'average particle size of 0.05 pm
to 0.50 pm, or a mixture or copolymer of two or three
kinds selected from the group: 1 part by mass to 50
parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 pm to 0.35 pm: 0.5 parts by mass to 10
parts by mass in resin solid content.
[0013] (5) A method for manufacturing an electrical
steel sheet, including:
applying a treatment solution on a surface of a
base iron; and
baking and drying the treatment solution,
wherein the treatment solution contains:
a first component: 100 parts by mass in solid
content, the first component containing:
a colloidal silica: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 pm
to 0.50 pm, or a mixture or copolymer of two or three
kinds selected from the group: 40 parts by mass to
400 parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 pm to 0.35 pm: 0.5 parts by mass to 10
parts by mass in resin solid content.
[0014] (6) The method for manufacturing an
electrical steel sheet according to (4) or (5),
wherein a temperature to be reached in the baking and
drying is 150°C to 350°C, and a time therefor is 5
seconds to 60 seconds.
[0015] (7) The method for manufacturing the
electrical steel sheet according to (4) or (5),
wherein the first component and the second component
account for 90% or more of the treatment solution
when it is converted into a solid content.
ADVANTAGEOUS EFFECTS OF INVENTION
[0016] According to the present invention, an
appropriate insulating film is provided, and
therefore, it is possible to obtain high removability
of a molding resin while insulation performance and
so on are kept high.
BRIEF DESCRIPTION OF DRAWINGS
[0017] [Fig. 11 g . 1 is a flo'wchart illustrating a
method for manufacturing an electrical steel sheet
according to an embodiment of the present invention;
and
[Fig. 21 Fig. 2 is a cross-sectional view
illustrating a structure of an electrical steel sheet
according to an embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0018] Hereinafter, embodiments of the prese'nt
invention will be described with reference to the
attached drawings. Fig. 1 is a flowchart
illustrating a method for manufacturing an electrical
steel sheet according to an embodiment of the present
invention, and Fig. 2 is a cross-sectional view
illustrating a structure of the electrical steel
sheet according to an embodiment of the present
invention.
[0019] In the present embodiment, first, a base iron
1 is produced (step Sl). For example, in production
of the base iron 1, first, a slab with a
predetermined composition is heated at approximately
1050°C to 1250°C, and is hot-rolled so as to produce a
hot-rolled steel sheet, and the hot-rolled steel
sheet is coiled. Then, the hot-rolled steel sheet is
cold-rolled while being uncoiled so as to produce a
cold-rolled steel sheet with a thickness of
approximately 0.15 mm to 0.5 mm, and the cold-rolled
- 8 -
steel sheet is coiled. Thereafter, the cold-rolled
steel sheet is annealed (finish annealed) at 750°C to
llOO°C. Thus, the base iron 1 is obtained.
Incidentally, the steel sheet may be annealed in the
range of 800°C to 1050°C as necessary before the coldrolling.
[0020] The composition of the base iron 1 is one
suitable for a non-oriented electrical steel sheet,
for example. Specifically, the base iron 1 contains,
for example, Si: 0.1 mass% or more and Al: 0.05 mass%
or more with the balance being composed of Fe and
inevitable impurities. Incidentally, Mn: 0.01 mass%
or more and 1.0 mass% or less may be contained in
addition to Si and Al. Besides, Sn: 0.01 mass% or
more and 1.0 mass% or less may be contained.
Further, the contents of representative elements such
as S, N and C are preferable to be less than 100 ppm,
and more preferable to be less than 20 ppm. The
higher the content of Si is, the higher its electric
resistance is and the higher its magnetic property
is. However, when the content of Si is more than 4.0
mass%, the brittleness may be significant.
Accordingly, the Si content is preferable to be 4.0
mass% or less. Besides, the higher the content of A1
is, the higher its magnetic property is. However,
when the content of A1 is more than 3.0 mass%, the
cold-rolling when the base iron 1 is produced may be
difficult. Accordingly, the A1 content is preferable
to be 3.0 mass% or less.
- 9 -
[0021] Incidentally, the composition of the base
iron 1 may be one suitable for a grain-oriented
electrical steel sheet.
[0022] Besides, the lower the surface roughness of
the base iron 1 is, the higher the adhesiveness
between electrical steel sheets in a laminated iron
core is. Accordingly, the centerline average
roughness (Ra) in the rolling direction of the base
iron 1 and in a direction (width direction)
orthogonal to the rolling direction is preferable to
be 1.0 pm or lower, and more preferable to be 0.5 pm
or lower. When the centerline average roughness (Ra)
is higher than 1.0 pm, the adhesiveness between
electrical steel sheets is low, with which it is
difficult to obtain high heat conductivity in a
lamination direction. Incidentally, it may be
necessary to strictly perform control of the coldrolling
to make the centerline average roughness (Ra)
be lower than 0.1 pm, which often leads to high
costs. Accordingly, it is preferable that the
centerline average roughness (Ra) be 0.1 pm or more.
[0023] Then, as illustrated in Fig. 2, an insulating
film 2 is formed on a surface of the base iron 1
(step S2). In formation of the insulating film 2, a
certain treatment solution is applied on the surface
of the base iron 1 (step S2a), and thereafter the
treatment solution is dried by heating (step S2b).
As a result, the components in the treatment solution
are baked onto the surface of the base iron 1. The
method of applying the treatment solution is not
particularly limited. For example, the treatment
solution may be applied using a roll coater or spray,
or the base iron 1 may be dipped into the treatment
solution. The method of drying the treatment
solution is also not particularly limited. For
example, an ordinary radiation furnace or air heating
furnace may be used to dry the treatment solution, or
the treatment solution may be dried by heating using
electric energy such as induction heating and highfrequency
heating. Regarding the conditions of the
drying and baking of the treatment solution (step
S2b), the temperature (baking temperature) for the
treatment is preferable to be at 150°C to 350°C, in
particular, the baking temperature is preferable to
be at 230°C to 300°C when a metal phosphate is
contained in the treatment solution as described
later. Besides, the time for this treatment is
preferable to be 5 seconds to 60 seconds when a metal
phosphate is contained in the treatment solution, and
preferable to be 3 seconds to 60 seconds when a
colloidal silica is contained in the treatment
solution.
[00241 Incidentally, pretreatment may be performed
on the surface of the base iron 1 before applying the
b treatment solution. For example, a degreasing
treatment using an alkaline chemical agent or the
like, an acid cleaning treatment using hydrochloric
acid, sulfuric acid, phosphoric acid or the like, and
- 11 -
so on may be cited as the pretreatment.
[0025] Here, the treatment solution used for forming
the insulating film 2 will be described. To classify
broadly, the following two kinds ((a), (b)) may be
used as the treatment solution.
(a) A treatment solution containing:
a first component: 100 parts by mass in solid
content, the first component containing:
a metal phosphate: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 pm
to 0.50 pm, or a mixture or copolymer of two or three
kinds selected from the group: 1 part by mass to 50
parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 pm to 0.35 pm: 0.5 parts by mass to 10
parts by mass in resin solid content.
(b) A treatment solution containing:
a first component: 100 parts by mass in solid
content, the first component containing:
a colloidal silica: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 pm
to 0.50 pm, or a mixture or copolymer of two or three
kinds selected from the group: 40 parts by mass to
400 parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 pm to 0.35 pm: 0.5 parts by mass to 10
parts by mass in resin solid content.
[0026] Incidentally, the total amount of the first
component and the second component is preferable to
be 90% or more of the entire treatment solution when
it is converted into a solid content. This is to
secure good insulation performance, heat
conductivity, heat resistance, and so on of the
insulating film.
[0027] Regarding the first component, the metal
phosphate is one to be the solid content when an
aqueous solution of which major constituents are
phosphoric acid and metal ions is dried. The kind of
the phosphoric acid composing the metal phosphate is
not particularly limited, and for example, an
orthophosphoric acid, a metaphosphoric acid, a
polyphosphoric acid, or the like may be used. The
kind of metal ions composing the metal phosphate is
also not particularly limited, and Li, Al, Mg, Ca,
Sr, Ti, Ni, Mn, Co and so on are preferable, where
Al, Ca, Mn and Ni are particularly preferable.
Further, it is preferable to prepare the metal
phosphate solution by mixing an oxide of a metal ion,
a carbonate, and/or a hydroxide in an orthophosphoric
acid, for example.
[0028] As the metal phosphate, just one kind may be
used, or two or more kinds may be mixed and used.
The first component may be composed of only the metal
phosphate, or may contain additives such as
phosphonic acid and/or boric acid.
[0029] Regarding the first component, as the
colloidal silica, it is preferable to use, for
example, one having an average particle size of 5 nm
to 40 nm and having an Na content of 0.5 mass% or
less. Further, the Na content of the colloidal
silica is more preferable to be 0.01 mass% to 0.3
mass%.
[0030] In the present embodiment, the first
component contains an emulsion of an acrylic resin,
an epoxy resin and/or a polyester resin. A
commercially available resin emulsion may be used as
the emulsion of the acrylic resin, the epoxy resin
and/or the polyester resin. The melting points of
the acrylic resin, the epoxy resin and/or the
polyester resin are not particularly limited, and are
preferable to be 50°C or lower. When the melting
points are higher than 50°C, they are likely to
generate powder. Further, in view of costs, the
melting points are preferable to be O°C or higher.
[0031] As the acrylic resin, it is preferable to be
methyl acrylate, ethyl acrylate, n-butyl acrylate, ibutyl
acrylate, n-octyl acrylate, i-octyl acrylate,
2-ethylhexyl &crylate, n-nonyl acrylate, n-decyl
acrylate, n-dodecyl acrylate, and the like, which are
normal monomers. As the acrylic resin, it is also
preferable to be ones obtained by copolymerizing
acrylic acid, methacrylic acid, maleic acid, maleic
anhydride, fumaric acid, crotonic acid, and itaconic
acid, which are monomers having a functional group,
as well as 2-hydroxylethyl(metha)acrylate, 2-
hydroxylpropyl(metha)acrylate, 3-
hydroxylbutyl(metha)acrylate, 2-
hydroxylethyl(metha)allylether, and so on, which are
monomers having a hydroxyl group.
[ 0 0 3 2 ] As the epoxy resin, for example, there are
ones obtained by bringing a carboxylic anhydride into
reaction with an amine-denatured epoxy resin.
Specifically, there are bisphenol A-diglycidyl ether,
a ring-opening adduct of caprolactone of bisphenol Adiglycidyl
ether, bisphenol F-diglycidyl ether,
bisphenol S-diglycidyl ether, novolac glycidyl ether,
dimer acid glycidyl ether, and the like. As the
amine for denaturing, there are isopropanolamine,
monopropanolamine, monobutanolamine,
monoethanolamine, diethylenetriamine,
ethylenediamine, butalamine, propylamine,
isophoronediamine, tetrahydrofurfurylamine,
xylenediamine, hexylamine, nonylamine,
triethylenetetramine, tetramethylenepentamine,
diaminodiphenylsulfone, and the like. As the
carboxylic anhydride, ones obtained by reaction with
succinic anhydride, itaconic anhydride, maleic
anhydride, citraconic anhydride, phthalic anhydride,
trimellitic anhydride, or the like are preferable.
[ 0 0 3 3 ] As the polyester resin, for example, one
a
obtained by bringing a dicarboxylic acid into
reaction with a glycol is preferable. As the
dicarboxylic acid, there are terephthalic acid,
I
I isophthalic acid, orthophthalic acid, naphthalene
1
dicarboxylic acid, biphenyl dicarboxylic acid,
succinic acid, adipic acid, sebacic acid, fumaric
acid, maleic acid, maleic anhydride, itaconic acid,
citraconic acid, and the like. As the glycol, there
are ethylene glycol, 1,2-propylene glycol, 1,3-
propanediol, 1,4-butanediol, 1,5-pentanediol,
neopentyldiol, 1,6-hexanediol, triethylene glycol,
dipropylene glycol, polyethylene glycol, and the
like. Ones obtained by graft polymerizing acrylic
acid, methacrylic acid, maleic acid, fumaric acid,
itaconic acid, citraconic acid, or methacrylic acid
anhydride, or the like with these polyester resins
may also be used.
[0034] As the acrylic resin, the epoxy resin, and
the polyester resin, just one kind may be used, or
two or more kinds may be mixed and used. Note that
as these organic resins, ones having an average
particle size of 0.05 pm to 0.50 pm are used. When
the average particle size is smaller than 0.05 pm, it
aggregates easily in the treatment solution, and the
evenness of the insulating film 2 decreases easily.
On 'the other hand, when the average particle size is
larger than 0.50 pm, stability of the treatment
solution decreases easily. If the stability of the
treatment solution decreases, there are possibilities
- 16 -
in which aggregates are generated in the treatment
solution, pipes and/or pumps are clogged, and the
aggregates enter into the insulating film 2 to
generate a defect in the insulating film 2. Besides,
the average particle size of these organic resins is
preferable to be 0.1 pm or more and preferable to be
0.3 pm or less. Incidentally, as for the average
particle size, for example, a number average particle
size regarding particles having a particle size of 1
pm or less may be used.
[0035] Regarding the mixing ratio of the metal
phosphate with the acrylic resin, the epoxy resin,
and the polyester resin, the total amount of the
acrylic resin, the epoxy resin, and the polyester
resin relative to 100 parts by mass of the metal
phosphate is 1 part by mass to 50 parts by mass.
When the total amount of the acrylic resin, the epoxy
resin, and the polyester resin is less than 1 part by
mass, an aggregation of the acrylic resin, the epoxy
resin, and the polyester resin occurs easily, and the
evenness of the insulating film 2 decreases easily.
On the other hand, when the total amount of the
acrylic resin, the epoxy resin, and the polyester
resin is more than 50 parts by mass, heat resistance
may be poor.
[0036] Besides, regarding the mcxing ratio of the
colloidal silica with the acrylic resin, the epoxy
resin, and the polyester resin, the total amount of
the acrylic resin, the epoxy resin, and the polyester
- 17 -
resin relative to 100 parts by mass of the colloidal
silica is 40 parts by mass to 400 parts by mass.
When the total amount of the acrylic resin, the epoxy
resin, and the polyester resin is less than 40 parts
by mass, it is difficult to properly form the
insulating film 2, and there is a possibility in
which the insulating film 2 generates powder. On the
other hand, when the total amount of the epoxy resin
and the polyester resin is more than 400 parts by
mass, the heat resistance may be poor.
[0037] Regarding the second component, for example,
polytetrafluoroethylene, tetrafluoroethyleneperfluoroalkylvinyl
ether copolymer,
tetrafluoroethylene-hexafluoropropylene copolymer,
tetrafluoroethylene-ethylene copolymer,
polychlorotrifluoroethylene, polyvinylidene fluoride,
tetrafluoroethylene-hexafluoropropyleneperfluoroalkyl
vinyl ether copolymer,
chlorotrifluoroethylene-ethylene copolymer, polyvinyl
fluoride, and so on can be used as the fluorine
resin.
[0038] Incidentally, when the fluorine resin to
which the hydroxyl group is grafted or which is
epoxy-denatured or the like is used, there is a
tendency in which the removability of the molding
resin deteriorates. Accordingly, it is preferable to
use the fluorine resin other than the fluorine resin
to which the hydroxyl group is grafted or which is
epoxy-denatured.
*
[0039] As the dispersion or powder of the fluorine
resin, one having the average particle size of 0.05
pm to 0.35 pm is used. When the average particle
size of the dispersion or powder of the fluorine
resin is less than 0.05 pm, enough dispersibility
cannot be obtained to be easy to aggregate in the
treatment solution, and the evenness of the
insulating film 2 decreases easily. As a result,
there is a case when enough properties such as the
insulation performance cannot be obtained. Besides,
when the average particle size is larger than 0.35
pm, stability of the treatment solution decreases
easily. Besides, the average particle size of the
dispersion or powder of the fluorine resin is
preferable to be 0.15 pm or more and preferable to be
0.25 pm or less.
[0040] Incidentally, the dispersion or powder of the
fluorine resin may be used independently or two or
more kinds may be mixed and used. For example,
plural kinds of dispersion or powder having different
average particle sizes may be mixed and used, or
plural kinds of dispersions or powders having
different molecular weights may be mixed and used.
Besides, the dispersion of the fluorine resin and the
powder of the fluorine resin may be mixed and used.
[0041] Regarding the'blending ratio of the first
component and the second component, the amount of the
second component relative to the 100 parts by mass in
solid content of the first component is 0.5 parts by
*
mass to 10 parts by mass whether the major
constituent of the first component is the metal
phosphate or the colloidal silica. When the amount
of the second component is less than 0.5 parts by
mass, there is a possibility in which the effect
improving the removability of the molding resin is
not sufficient. On the other hand, when the amount
of the second component is higher than 10 parts by
mass, there is a possibility in which the stability
of the treatment solution deteriorates. As stated
above, if the stability of the treatment solution
decreases, there are possibilities in which
aggregates are generated in the treatment solution,
pipes and/or pumps are clogged, and the aggregates
enter into the insulating film 2 to generate a defect
in the insulating film 2. Besides, the fluorine
resin has a tendency particularly aggregating at an
interface different from the other organic resins,
and therefore, there is a possibility in which the
adhesiveness with the base iron 1 is insufficient
when the amount of the second component exceeds 10
parts by mass.
[0042] Incidentally, additives such as a surfactant
may be added to the above-described treatment
solution. As the surface active agent, non-ion
surfactants are preferable, and a brightener, an
antiseptic, an antioxidant, and the like may be added
in addition to the above.
[0043] Besides, the other components may be added to
the above-described treatment solution. For example,
an inorganic compound such as carbonate, hydroxide,
oxide,. titanate, and tungstate may be added, and an
organic low-molecular compound such as polyol,
cellosolve, carboxylic acids, ethers, and esters may
be added. Further, both of the inorganic compound
and the organic low-molecular compound may be added.
[0044] In the electrical steel sheet 10 manufactured
as stated above, the insulating film 2 contains, when
the treatment solution (a) is used:
a first component: 100 parts by mass, the first
component containing:
a metal phosphate: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 pm
to 0.50 pm, or a mixture or copolymer of two or three
kinds selected from the group: 1 part by mass to 50
parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 pm to 0.35 pm: 0.5 parts by mass to 10
parts by mass.
[0045] Besides, the insulating film 2 contains, when
the treatment solution (b) is used:
a fir9t component: 100 parts by mass, the first
component containing:
a colloidal silica: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 pm
to 0.50 pm, or a mixture or copolymer of two or three
kinds selected from the group: 40 parts by mass to
400 parts by mass; and
a second component composed of particles of one
or more kinds selected from a group consisting of a
polyolefin wax, an epoxy resin and an acrylic resin,
the particles having an average particle size of 2.0
pm to 15.0 pm and a melting point of 60°C to 140°C: 5
parts by mass to 45 parts by mass in resin solid
content.
[0046] Besides, one in which the fluorine resin is
dispersed inside is obtained as the insulating film
2. Dispersibility in the treatment solution is
extremely good when the average particle size of the
dispersion or powder of the fluorine resin is 0.05 pm
to 0.35 pm, and therefore, the dispersibility of the
fluorine resin in the insulating film 2 is extremely
good, and a substantial surface tension moderately
decreases for a whole of the insulating film 2. As a
result, the removability of the molding resin
improves. In other words, in the electrical steel
sheet 10 including the insulating film 2 as stated
above, it is possible to appropriately set the
adhesiveness with the molding resin while highly
keeping the adhesiveness of the insulating film 2
with the base iron 1. For example, it is possible to
enable to relieve the compressive stress, and to
*
improve workability when an excessive molding resin
is peeled off, and so on while securing the
adhesiveness and so on required to fix the magnet.
Incidentally, when the average particle size of the
fluorine resin is not appropriate, there is a
possibility in which the properties of the insulating
film 2 vary because the fluorine resin disperses in
the insulating film 2 unevenly.
LO0471 Incidentally, when the surfactant, the
inorganic compound, the organic low-molecular
compound, or the like is added to the treatment
solution, these are contained in the insulating film
2 as they are.
[ 0 0 4 8 ] Besides, a thickness of the insulating film 2
is preferable to be approximately 0 . 3 pm to 3 . 0 pm,
more preferable to be 0 . 5 pm or more, and 1.5 pm or
less.
[ 0 0 4 9 ] Incidentally, the average particle sizes of
the colloidal silica, the average particle sizes of
the acrylic resin, the epoxy resin, and the polyester
resin, and the average particle size of the fluorine
resin are the number-average particle sizes. As the
number average particle size of the colloidal silica,
for example, one measured by a nitrogen absorption
method (JIS 2 8 8 3 0 ) is used. Further, as the number
'average particle sizes of the acrylic resin, the
epoxy resin, the polyester resin and the fluorine
resin, for example, ones measured by a laser
diffraction method are used.
[0050] As the treatment solution, it is preferable
to use one containing no Cr in consideration of
environment.
[0051] Besides, it is preferable that the first
component and the second component account for 90% or
more of the insulating film 2. This is for securing
good insulation performance, heat conductivity, heat
resistance, and so on.
EXAMPLE
[0052] Next, experiments performed by the present
inventors are described. Conditions and so on in
these experiments are examples applied to verify
execution possibilities and effects of the present
invention, and the present invention is not limited
to these examples.
[0053] A base iron having a composition for a nonoriented
electrical steel sheet containing Si: 2.5%,
Al: 0.5%, and Mn: 0.05% each in mass% was produced.
The thickness of the base iron was 0.35 mm, and the
centerline average roughness (Ra) was 0.46 pm.
[0054] Further, various solutions for the first
component were prepared. The components of these
solutions are presented in Table 1.
[0055] [Table 11
- o TABLE 1
0
Cn - SOLUTION No. FOR
FIRST COMPONENT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
METAL PHOSPHATE OR
COLLOIDAL SILICA
MAGNESIUM PHOSPHATE
ALUMINUM PHOSPHATE
MANGANESE PHOSPHATE
NICKEL PHOSPHATE
ALUMINUM PHOSPHATE +
MAGNESIUM PHOSPHATE
COLLOIDAL SILICA
COLLOIDAL SILICA
COLLOIDAL SILICA
MAGNESIUM PHOSPHATE
ALUMINUM PHOSPKTiTE
ALUMINUM PHOSPHATE
CALCIUM PHOSPHATE
ALUNINUM PHOSPHATE
COLLOIDAL SILICA
COLLOIDAL SILICA
COLLOIDAL SILICA
MAGNESIUM CHROMATE
KIND OF
ORGANIC RESIN
ACRYLIC RESIN 1
ACRYLIC RESIN 1
EPOXY RESIN 1
ACRYLIC RESIN I
POLYESTER RESIN
EPOXY RESIN 1
ACRYLIC RESIN 1
EPOXY RESIN 1
ACRYLIC RESIN 2
EPOXY RESIN 2
ACRYLIC RESIN 1
POLYESTER RESIN
AQUEOUS
POLYURETHANE
EPOXY RESIN 2
EPOXY RESIN 1
ACRYLIC RESIN I
ACRnIC RESIN 1
PART BY
MASS OF
ORGANIC RESIN
20
7
35
15
15
45
100
330
30
30
0.5
60
30
30
35
430
30
OTHER
rnDITIVE
PHOSPHONIC ACID:
0.5 PARTS BY MASS
phosphate, an orthophosphoric acid and metal
hydroxides such as Mg(OH)2 and ~1 (OH)3, a metal oxide
and a metal carbonate were mixed and stirred, thereby
preparing an aqueous solution of 40 mass%.
[0057] Regarding the solutions containing a
colloidal silica, a solution containing 30 mass% of
commercially available colloidal silica having an
average particle size of 15 nm with a surface being
modified by aluminum was prepared.
[0058] Details of the six kinds of organic resins in
Table 1 are as follows.
[0059] [Acrylic resin 11
This is an acrylic resin obtained by
copolymerizing methyl methacrylate: 40 mass%, 2-
hydroxyethyl methacrylate: 10 mass%, n-butyl
acrylate: 30 mass%, and styrene monomer: 20 mass%.
[Acrylic resin 21
This is an acrylic resin obtained by
copolymerizing methyl acrylate: 40 mass%, styrene
monomer: 30 mass%, isobutyl acrylate: 20 mass%, and
fumaric acid: 10 mass%.
[Epoxy resin 11
This is a carboxyl-group denatured epoxy resin
obtained by denaturing bisphenol A- with
triethanolamine and thereafter bringing succinic
anhydride into reaction therewith.
[Epoxy resin 21
This is an epoxy resin obtained by blending an
ethylene propylene block polymer with a phenolnovolac
epoxy resin and adding nonylphenyl ether
ethylene oxide thereto, thereby making it a selfemulsifying
type.
[Polyester resin]
This is a polyester resin containing a carboxylgroup
obtained by copolymerizing dimethyl
terephthalate: 35 mass% and neopentyl glycol: 35
mass% and thereafter graft polymerizing fumaric acid:.
15 mass% and trimellitic anhydride: 15 mass%.
[Aqueous polyurethane]
This is aqueous polyurethane synthesized from
hexamethylene diisocyanate and polyethylene glycol by
a known method.
[0060] These organic resins were each made as a 30%
emulsion solution, and they were mixed with a
solution containing the metal phosphate or the
colloidal silica. Furthermore, a proper amount of
viscosity improver and surfactant was added as
necessary to prepare the solutions presented in Table
1.
[0061] Incidentally, average particle sizes of the
acrylic resins 1, 2 were 0.25 pm, 0.64 pm, 0.6 pm,
respectively. The average particle sizes of the
epoxy resins 1, 2 were 0.33 pm, 0.76 pm,
respectively, and the average particle size of the
polyester resin was 0.35 pm, the average particle
size of the aqueous polyurethane was 0.12 pm. In
measurement of these average particle sizes, the
resin emulsion was diluted with distilled water, and
thereafter a number average particle size was
measured with a commercially available particle size
measuring apparatus using a laser diffraction method
according to a JIS method (JIS 28826). Incidentally,
the parts by mass of resins in Table 1 are values
converted into a solid content.
[0062] Then, predetermined amounts of dispersion or
powder of the fluorine resins presented in Table 2
were added to the solutions presented in Table 1 so
as to prepare 27 kinds of treatment solutions.
[0063] [Table 21
TABLE 2
SAMPLE
No.
1
2
3
4
5
6
7
B
9
10
11
12
13
14
15
16
17
18
15
2 0
21
2 2
23
2 4
2 5
2 6
2 7
SOLUTION No. FOR
FIRST COMPONENT
1
2
2
3
4
KIND OF
FLUORINE RESIN
FLUORINE RESIN 1
FLUORINE RESIN 2
FLUORINE RESIN 3
FLUORINE RESIN 6
FLUORINE RESIN 2
ADDED AMOUNT OF
FLUORINE RESIN
PART BY MASS)
3.5
5
8
5
---0. 5
4
5
6
7
8
3
3
9
10
11
12
13
14
15
16
I
2
3
2
6
7
17
EXAMPLE
COMPARATIVE
EXAMPLE
330
230
200
2 80
300
200
280
300
280
330
230
2 60
330
2 60
2 60
32 0
200
160
280
400
230
330
FLUORINE RESIN 2
FLUORINE RESIN 2
FLUORINE RESIN 2
E~JUORINERE SIN 2
ELUORINE RESIN 2
FLUORINE RESIN 4
FLUORINE RESIN 5
FLUORINE RESIN 4
FLUORINE RESIN 4
FLUORINE RESIN 2
FLUORINE RESIN 3
FLUORINE RESIN 2
FLUORINE RESIN 2
ELUORINE RESIN 2
FLUORINE RESIN 2
REblARKS
35
55
40
3 0
20
40
3 0
15
40
15
5 5
20
3 5
40
3 5
2 0
36
5 5
3 0
5
3 0
3 0
BAKING
TEMPERATURE
("c )
320
280
2 60
300
280
2.5
1
3
6
3
5
5
5
5
2.5
6
5
6
6
6
CONDITION
TIME
I(SEC)
20
30
2 0
15
4 0
NONE
E%UORINE RESIN 1
FLUORINE RESIN 1
FLUORINE RESIN 2
ELUORINE RESIN 2
FLUORINE RESIN 2
0.04
15
20
0.03
12
NONE
This is the dispersion of a fluorine resin in a
polytetrafluoroethylene (PTFE) type, having the
average particle size of 0.25 pm, and a concentration
of 48 mass%.
[Fluorine resin 21
This is the dispersion of a fluorine resin in a
fluorinated ethylene propylene ( F E P ) type, having the
average particle size of 0.34 pm, and the
concentration of 50 mass%.
[Fluorine resin 31
This is the dispersion of a fluorine resin made
to be a water dispersion type by a forced
emulsification, having the average particle size of
0.12 pm, and the concentration of 60 mass%.
[Fluorine resin 41
This is the powder of the fluorine resin in a
fluorine rubber type, having the average particle
size of 2.5 pm.
[Fluorine resin 51
This is the dispersion of the fluorine resin in
a hydroxyl group grafted type, having the average
particle size of 0.06 pm, and the concentration of 48
mass%.
[Fluorine resin 61
This is the powder of the fluorine resin
+ compounding PTFE, having the average particle size of
0.33 pm and vinylidene fluoride having the average
particle size of 0.25 pm.
[0065] Incidentally, in measurement of the average
particle size of the emulsion of the organic resin,
the resin emulsion was diluted with distilled water,
and thereafter a number average particle size was
measured with the commercially available particle
size measuring apparatus using the laser diffraction
method according to the JIS method (JIS 28826).
Besides, in measurement of the average particle size
of the powder of the fluorine resin, the powder is
dispersed in the distilled water by an ultrasonic
washing machine for approximately one minute, and
thereafter a number average particle size was
measured with the commercially available particle
size measuring apparatus using the laser diffraction
method according to the JIS method (JIS 28826).
Moreover, the centerline average roughness (Ra) is
measured by using a commercially available surface
roughness measuring apparatus according to a JIS
method (JIS B0601) as for the surface roughness.
[0066] Then the treatment solutions are applied on
the base iron and baked under the conditions
presented in Table 2. The treatment solutions were
applied using the roll coater. At this time, the
amount of pressing down with the roll and so on were
adjusted so that a thickness of the insulating film
becomes approximately 0.8 pm. The baking (drying)
was performed using the rbdiation furnace, and the
setting of the furnace temperature was adjusted so as
to obtain the predetermined heating conditions noted
in Table 2. They were adjusted so that the sheet
temperatures reached were 160°C to 400°C, and the
baking times were five seconds to 55 seconds.
[0067] Then, various properties of the electrical
steel sheets obtained after the baking was finished
were evaluated. Specifically, evaluations were
performed on removability of the molding res,in,
insulation performance, adhesiveness, corrosion
resistance, appearance, and heat resistance.
[0068] In evaluation of the removability of the
molding resin, samples of two pieces of electrical
steel sheets sandwiching the powder of the molding
resin of 0.05 g was heated to 150°C, held for one
minute with a pressurizing force of 10 kgf/cm2, aircooled,
and shearing tensile strength was measured.
The measurement of the shearing tensile strength was
performed according to a JIS method (JIS K6850), and
the shearing tensile strength was set to be a molding
resin adhesive force. Incidentally, 1 kgf/cm2 is
approximately 9.8 ~ / c m ~W.he n the shearing tensile
strength is 10 kgf/cm2 or less, it can be said that
the removability of the molding resin is good. On
the other hand, when the shearing tensile strength
exceeds 10 kgf/cm2, there is a possibility in which
magnetism deteriorates by the molding resin, besides,
there is a possibility in which workability when
adherents are removed and so on deteriorates if it is 1
used for the fixing of the magnet.
[0069] In evaluation of the insulation performance,
interlayer resistance was measured according to a JIS
method (JIS C2550). Then, one with interlayer
resistance of less than 5 ~ - c m ~ / ~ i weacse e valuated as
x , one with interlayer resistance of 5 ~ . c m ~ / ~ i etoc e
10 ~.cm*/~iecwaes evaluated as A, one with interlayer
resistance of 10 ~ . c m ~ / ~ i etoc e5 0 ~.cm*/~iecwaes
evaluated as 0, and one with interlayer resistance of
50 ~.crn~/~ieocr em ore was evaluated as 0.
[0070] In evaluation of the adhesiveness, an
adhesive tape was put on electrical steel sheet
samples, and thereafter they were wrapped around
metal bars having a diameter of 10 mm, 20 mm, 30 mm.
Then the adhesive tape was peeled off, and the
adhesiveness was evaluated from the peeled state.
One which did not peel when wrapped around the metal
bar having the diameter of 10 mm was evaluated as 10
mmq OK, and one which did not peel when wrapped
around the metal bar having the diameter of 20 mm was
evaluated as 20 rnmq OK. Further, one which did not
peel when wrapped around the metal bar having the
diameter of 30 mm was evaluated as 30 mmq OK, and one
which peeled off when wrapped around the metal bar
having the diameter of 30 mm was evaluated as 30 rnmq
OUT.
[0071] The corrosion resistance was evaluated
according to a salt spray test of JIS method (JIS
22371). Samples after 7 hours elapsed were used to
perform 10-point evaluation. Criteria of evaluation
are as follows.
[0072] 10: No rust occurred
9: Slight rust occurred (0.1% or less in area
ratio)
8: Area ratio of rust occurred = more than 0.1%
and 0.25% or less
7: Area ratio of rust occurred = more than 0.25%
and 0.50% or less
6: Area ratio of rust occurred = more than 0.50%
and 1% or less
5: Area ratio of rust occurred = more than 1% and
2.5% or less
4: Area ratio of rust occurred = more than 2.5%
and 5% or less
3: Area ratio of rust occurred = more than 5% and
10% or less
2: Area ratio of rust occurred = more than 10%
and 25% or less
1: Area ratio of rust occurred = more than 25%
and 50% or less
[0073] In evaluation of the appearance, one which
was glossy, smooth and even was evaluated as 5, one
which was glossy but less even was evaluated as 4,
one which was slightly glossy and smooth but poor in
evenness was evaluated as 3, one which had low gloss,
slightly poor in smoothness and poor in evenness was
evaluated as 2, and one which was poor in gloss,
evenness, and smoothness was evaluated as I!
[0074] As for the heat resistance, a 2 mm x 30 mm
gauze was rubbed on an electrical steel sheet surface
with a load of 100 gf (approximately 0.98 N), and the
heat resistance was evaluated based on a peeling
state of the insblating film. One which did not peel
was evaluated as 5, one which slightly peeled was
evaluated as 4, one which clearly peeled was
evaluated as 3, one which severely peeled was
evaluated as 2, and one which peeled without being
rubbed with the gauze was evaluated as 1.
[0075] These evaluation results are presented in
Table 3.
[0076] [Table 31
[ 0 0 7 7 ] As presented in Table 3, the effects of the
present invention were clear in this experiment.
Specifically, as presented in Table 3, in the samples
corresponding to the examples of the present
invention, the adhesiveness of the molding resin was
10 kgf/cm2 or less, and it can be said that there is
the excellent removability of the molding resin.
Besides, it was also clear that the samples
corresponding to the examples of the present
invention also excelled in the insulation
performance, adhesiveness, corrosion resistance,
appearance and heat resistance in addition to the
removability of the molding resin. Further, in many
of the samples corresponding to the comparative
examples, the adhesiveness of the molding resins were
large values higher than 10 kgf/cm2, and none of them
excelled in all of the insulation performance,
adhesiveness, corrosion resistance, appearance and
heat resistance.
[0078] As has been described, in the electrical
steel sheet according to the embodiment of the
present invention, the removability of the molding
resin is good, iron loss properties of the laminated
iron core improve, and insulating film properties of
the electrical steel sheet are good in, for example,
the laminated iron core in molding and so on.
[0079] In the foregoing, the preferred embodiment of
the present invention has been described in detail,
but the in-vention is not limited to such an example.
It is clear that any person having common knowledge
in the art to which the invention pertains will be
- 37 -
able to contrive various examples of changes and
modifications within the category of the technical
idea described in the claims, and it is understood
that such changes and modifications naturally belong
to the technical scope of the present invention.
INDUSTRIAL APPLICABILITY
[ 0 0 8 0 ] The present invention may be used in, for
example, electrical steel sheet manufacturing
industry and electrical steel sheet utilizing
industry.

CLAIMS
[Claim 1] An electrical steel sheet, comprising:
a base iron; and
an insulating film formed on a surface of the
base iron,
wherein the insulating film contains:
a first component: 100 parts by mass, the first
component containing:
a metal phosphate: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 \im
to 0.50 ]im, or a mixture or copolymer of two or three
kinds selected from the group: 1 part by mass to 50
parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having, an average particle
size of 0.05 ^.m to 0.35 |j,m: 0.5 parts by mass to 10
parts by mass.
[Claim 2] An electrical steel sheet, comprising:
a base iron; and
an insulating film formed on a surface of the
base iron,
wherein the insulating film contains:
a first component: 100 parts by mass, the first
component containing: *
a colloidal silica: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
- 39 -
#
resin which have an average particle size of 0.05 ]im
to 0.50 \im, or a mixture or copolymer of two or three
kinds selected from the group: 40 parts by mass to
400 parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 |j,m to 0.3 5 |j,m: 0.5 parts by mass to 10
parts by mass.
[Claim 3] The electrical steel sheet according to
claim 1, wherein the first component and the second
component account for 90% or more of the insulating
film.
[Claim 4] The electrical steel sheet according to
claim 2, wherein the first component and the second
component account for 90% or more of the insulating
film.
[Claim 5] A method for manufacturing an electrical
steel sheet, comprising:
applying a treatment solution on a surface of a
base iron; and
baking and drying the treatment solution,
wherein the treatment solution contains:
a first component: 100 parts by mass in solid
content, the first component containing:
a metal phosphate: 100 parts by mass; and
orte kind selected from a group consisting of
anacrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 \iin.
to 0.50 ijm, or a mixture or copolymer of two or three
- 40 -
kinds selected from the group: 1 part by mass to 50
parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 fj,m to 0.3 5 ^m: 0.5 parts by mass to 10
parts by mass in resin solid content.
[Claim 6] A method for manufacturing an electrical
steel sheet, comprising:
applying a treatment solution on a surface of a
base iron; and
baking and drying the treatment solution,
wherein the treatment solution contains:
a first component: 100 parts by mass in solid
content, the first component containing:
a colloidal silica: 100 parts by mass; and
one kind selected from a group consisting of
an acrylic resin, an epoxy resin and a polyester
resin which have an average particle size of 0.05 pm
to 0.50 ]im, or a mixture or copolymer of two or three
kinds selected from the group: 40 parts by mass to
400 parts by mass; and
a second component composed of dispersion or
powder of a fluorine resin having an average particle
size of 0.05 )j,m to 0.35 |jm: 0.5 parts by mass to 10
parts by mass in resin solid content.
[Claim 7] The method for manufacturing an electrical
steel sheet according to claim 5, wherein a
temperature to be reached in the baking and drying is
150°C to 350°C, and a time therefor is 5 seconds to 60
- 41 -
seconds.
[Claim 8] The method for manufacturing an electrical
steel sheet according to claim 6, wherein a
temperature to be reached in the baking and drying is
150°C to 350°C, and a time therefor is 3 seconds to 60
seconds.
[Claim 9] The method for manufacturing an electrical
steel sheet according to claim 5, wherein the first
component and the second component account for 90% or
more of the treatment solution when it is converted
into a solid content.
[Claim 10] The method for manufacturing an
electrical steel sheet according to claim 6, wherein the first component and the second component account for 90% or more of the treatment solution when it is converted into a solid content.