DESCRIPTION
Title of Invention
CHROMATE FREE COLOR COATED METAL PLATE AND AQUEOUS COLOR
COMPOSITION
Technical Field
[OOO 11
The present invention relates to an inexpensive chromate-free color coated metal
plate on which a color coating not including hexavalent chromium with high
environmental burden characteristics is formed on at least one side of a metal plate, and
is extremely superior in design characteristics (colorability and concealment of sites
including worked portions), humidity resistance, corrosion resistance, workability,
scratch resistance, chemical resistance and the like.
Priority is claimed on Japanese Patent Application No. 2010-268184, filed on
December 1,2010, the content of which is incorporated herein by reference.
Background Art
[0002]
In uses such as home appliances, building materials and automobiles, precoated
steel plates coated with a colored organic coating have been used replacing post coating
products of the related art coated after fabrication. Since the precoated steel plates are
steel plates subjected to rust proofing or plated steel plates which are coated with a
colored organic coating, the plates have good workability and corrosion resistance while
having beauty.
2
[0003]
For example, Patent Document 1 discloses a technology obtaining a precoated
steel plate with superior workability, contamination resistance, and hardness through
defining a coating structure. On the other hand, Patent Document 2 discloses a
precoated steel plate with improved corrosion resistance of the surface on and close to
edges of the steel plate by using a specified chromate treatment solution. These
precoated steel plates have the object of having workability, coating adhesiveness and
corrosion resistance, omitting coating after fabrication, and improved productivity and
quality through the combined effects of plating layers, chromate treated films, and primer
films (undercoating) to which a chromium-based rust proofing pigment is added.
[0004]
However, considering the burden on the environment of hexavalent chromium
with the possibility of eluting from organic coatings, including chromate treated films or
a chromium-based rust proofing pigment, demand has been increasing recently with
respect to non-chromium rust proofing and non-chromium organic coatings. With
respect thereto, for example, Patent Document 3 and Patent Document 4 disclose
non-chromium based precoated steel plates with superior corrosion resistance, which
have been put into practical use.
[0005]
The coating used on these precoated steel plates has a coating thickness of 10
pm or more. In addition, because a large volume of solvent-based coating material is
used, dedicated coating facilities, such as incinerators or odor countermeasure facilities
are needed, and manufacturing on dedicated coating lines is usuaI. In other words,
because of passing through extra coating steps in addition to a manufacturing step of a
steel plate which is the base plate for coating, significant costs are incurred in addition to
4 3
the material costs required for coating. Accordingly, the obtained precoated steel plates
I are expensive.
I [0006]
I
I However, due to diversification of user needs, there is demand for colored steel
5 plates in a field sufficiently achieving the object if having durability under ordinary usage
conditions for domestic appliances or interior decoration building materials, and
lower-cost products are required. In other words, the high cost precoated steel plates of
the related art alone are insufficient in responding to diversified demand.
[0007]
10 With regard to such needs, as a colored steel plate able to be inexpensively
manufactured, for example, Patent Document 5 discloses a colored steel plate provided
with a colored resin layer with a thickness of 5 pm or less, and Patent Document 6
discloses a colored steel plate having a color developing film on a steel plate surface
having a specified roughness. However, because the colored steel plates have a design
15 securing corrosion resistance by providing a chromate treated film, the plates are unable
to respond to current needs for changes to non-chromium materials. In addition,
because the design does not take into consideration up to the concealment of sites which
are worked and in which the colored layers are stretched, there is also a problem in which
the appearance of worked portions is remarkably lowered.
20 [OOOS]
In addition, Patent Document 7 discloses a surface treated metal material with
improved characteristics, such as alkali resistance and solvent resistance, by using a
polyurethane resin containing a silanol group and a bond of a silanol group derivative.
However, in a case where the silanol group or the bond of the silanol group derivative are
25 contained in the polyurethane resin, there are also problems in that the workability and
A 4
corrosion resistance are not sufficiently exhibited, and further, sufficient performance
regarding chemical resistance is not exhibited.
[0009]
In addition, Patent Document 8 discloses an aqueous surface treatment
composition obtained through reaction of an epoxy prepolymer (I) having an amino
group and a urethane prepolyrner (II), and containing an aqueous dispersion of a
polyurethane resin containing a polyalkylene oxide group, and an antirust agent.
However, the aqueous surface treatment composition also has problems in that the
adhesiveness to the underlaying metal is insufficient, and further, sufficient performance
regarding workability and chemical resistance is not exhibited.
[OO 1 01
In addition, in the case of using a coated steel plate with design characteristics
coated by coloring with the surface treatment coating disclosed in Patent Document 7 or
Patent Document 8 as a material for a back cover for a thin television, when surface
contamination of the back cover is removed using a cleaning agent including alcohol,
defects may occur where the coating film is dissolved or changes color.
Citation List
Patent Documents
[OO 111
[Patent Document 11 Japanese Unexamined Patent Application, First
Publication No. H8-168723
patent Document 21 Japanese Unexamined Patent Application, First
Publication No. H3-100180
[Patent Document 31 Japanese Unexamined Patent Application, First
* 5
Publication No. 2000-199075
patent Document 41 Japanese ~nexaminedP atent Application, First
Publication No. 2000-262967
[Patent Document 51 Japanese Unexamined Patent Application, First
5 Publication No. H5-16292
[Patent Document 61 Japanese Unexamined Patent Application, First
Publication No. H2-93 093
[Patent Document 71 Japanese Unexamined Patent Application, First
Publication No. 2008-25023
10 [Patent Document81 Japanese Unexamined Patent Application, First
Publication No. 2009-127061
Summary of Invention
Technical Problem
15 [00 121
The present invention, taking the above situation into account, has as an object
to provide an inexpensive chromate-fiee color coated metal plate having extremely
superior design characteristics (colorability and concealment of sites including worked
portions), humidity resistance, corrosion resistance, workability, scratch resistance, and
20 chemical resistance, without including hexavalent chromium with high environmental
burden characteristics.
Solution to Problem
[00 131
25 In other words, the main points of the inventions are as follows.
a 6
(1) According to a first aspect of the invention, provided is a chromate-free
color coated metal plate with superior chemical resistance having, on at least one side of
the metal plate, a color coating (a) including a film forming component including a
polyurethane resin (Al) containing a urea group, a urethane group and a carboxyl group;
5 a color pigment (B); spherical silica particles (C) with an average particle diameter of 5
to 50 nm, wherein the polyurethane resin (Al) has a polyester polyol component (a)
derived structural unit having an aromatic ring structure, an isocyanate component (b)
derived structural unit having an aromatic ring structure, all of the isocyanate component
(b) derived structural units contain aromatic rings, and the color coating film (a) has a
10 film thickness of 2 to 10 pm.
(2) The chromate-free color coated.meta1 plate with superior chemical
resistance according to (1) in which the aromatic ring structure in the isocyanate
component (b) having an aromatic ring structure may be contained in the polyurethane
resin (Al) at 5 to 20 mass%.
I
I 15 (3) The chromate-fiee color coated metal plate with superior chemical
resistance according to (2) in which the aromatic ring structure in the polyester polyol
component (a) having an aromatic ring structure may be contained in the polyurethane
1 resin (Al) at 5 to 25 mass%.
(4) The chromate-free color coated metal plate with superior chemical
I 1 20 resistance according to any one of (1) to (3), in which the isocyanate component (b) may
be tolylene diisocyanate.
(5) The chromate-fiee color coated metal plate with superior chemical
1 resistance according to any one of (1) to (4), in which the film forming component of the
color coating film (a) may further contain a polyester resin (A2) containing a sulfonate
(6) The chromate-fiee color coated metal plate with superior chemical
resistance according to anyone of (1) to (5) in which the film forming component of the
color coating film (a) may be cured by a curing agent (D).
5 (7) The chromate-free color coated metal plate with superior chemical
resistance according to any one of (1) to (6), in which the color coating film (a) may
further include a lubricant (E).
(8) The chromate-fiee color coated metal plate with superior chemical
I resistance according to any one of (1) to (7), which may have a subbing layer (P) as the
10 lower layer of the color coating film (a).
(9) According to a second aspect of the invention, a chromate-free color
coated metal plate on which the color coating film (a) according to any one of (1) to (8)
is formed on at least one surface of a metal plate using an aqueous medium by coating
and heat-drying a color composition including a coating film constituent component.
(10) According to a third aspect of the invention, an aqueous color
composition includes a polyurethane resin (Al) containing a urea group, a urethane
group and a carboxyl group; a color pigment (l3); and spherical silica particles (C) in
which the polyurethane resin (Al) has a polyester polyol component (a) derived
structural unit having an aromatic ring structure; an isocyanate component (b) derived
structural unit having an aromatic ring structure, and all of the isocyanate component (b)
derived structural units contain aromatic rings.
(1 1) The aqueous color composition according to (10) in which the aqueous
color composition may further contain a polyester resin (A2) containing a sulfonate
group.
Advantageous Effects of Invention
[00 141
The chromate-free color coated metal plate of the invention is inexpensive and
5 extremely superior in design characteristics (colorability and concealment of sites
including worked portions), humidity resistance, corrosion resistance, workability,
scratch resistance, chemical resistance and the like, without including hexavalent
chromium with high environmental burden characteristics. Moreover, since the organic
resin as a film forming component for coating film formation may not necessarily be
10 cross-linked and cured, it is possible for energy costs to be suppressed and productivity to
be improved. Therefore, it is extremely promising as an inexpensive, high design
characteristics, high value added and environmentally-friendly material and the
contribution to various industrial fields is extremely large.
Description of Embodiments
[00 1 51
As described above, in a color coated metal plate used primarily in design
applications, various capabilities are required starting with design characteristics, to
humidity resistance, corrosion resistance, workability, scratch resistance, chemical
resistance or the like. In the related art, in order to correspond to these needs, a coated
metal plate is used in which an organic resin (for example, polyester or melamine based
resin) crosslinked and cured with a curing agent is set as the film forming component,
and a coating film in which a color pigment is dispersed therein is formed on the upper
layer of the metal plate at a comparatively thick film thickness of 10 pm or more. The
coating film, being a thick film and having a color pigment dispersed therein, requires
using an organic resin, which is crosslinked and cured with a curing agent, as a binder
component in order to increase the cohesion of the coating film and secure various
capabilities. Sufficient baking temperature and baking time are needed in order for the
organic resin to be crosslinked and cured, which leads to increases in energy costs and
5 lowering of productivity, and is a principal factor in manufacturing cost increases.
[00 161
Accordingly, the inventors conducted extensive research into a color coating
able to secure various capabilities even as a comparatively thin film and without using a
curing agent, and discovered using an organic resin containing a specified functional
10 - group in the resin structure as a film forming component, and furthermore, that by a color
pigment for securing design characteristics and silica particles for improving corrosion
resistance and scratch resistance being contained therein, it is possible to secure various
capabilities, such as extremely superior design characteristics, humidity resistance,
corrosion resistance, workability, scratch resistance, or chemical resistance. In
15 particular, workability and corrosion resistance, and chemical resistance are technically
in an inverse relationship, and further capabilities are greatly influenced by the organic
resin which is a film forming component, hence the inventors conducted thorough
research into organic resin design in order for these to be compatible at high dimensions,
and succeeded in securing workability, corrosion resistance and chemical resistance of
20 unprecedented superiority.
Specifically, the organic resin used as a film forming component is a
polyurethane resin containing a urea group, a urethane group and a carboxyl group;
further containing a polyester polyol component derived structural unit and an isocyanate
component derived structural unit having aromatic ring structures, and all of the
25 isocyanate component derived structural units contain aromatic rings. Since the urea
group and urethane group, and in particular the urea group, have extremely high cohesion
energy, they have an effect of increasing the cohesion of the color coating in the same
manner as crosslinking and curing using a curing agent. The carboxyl group has the
effect increasing the adhesiveness to the metal plate which is the base material (subbing
layer in the case of surface preparation).
In the invention, a polyurethane resin obtained by a urethane prepolymer
(isocyanate group remains), obtained by causing a urethane forming reaction of a polyol
compound including a polyester polyol component having an aromatic ring structure and
an isocyanate compound having an aromatic ring structure in conditions of an excess of
an isocyanate group included in an isocyanate compound, and undergoing chain
elongation with a polyamine compound is used. The urethane group is formed by
reaction of a polyol component and an isocyanate component, a urea group is formed by
being further reacted with a polyamine compound, and is made ultrahigh molecular
weight. In so doing, the polyurethane resin containing the urethane group and urea
group in the resin structure and made supramacromolecular is comparatively superior in
balance between workability and corrosion resistance; however, on the other hand, a
resin containing these functional groups is easy affected by chemicals, and has a problem
of degradation in chemical resistance.
The inventors first noticed the point that the urethane group and urea group
generated during reaction of an isocyanate component are most easily affected by
chemicals, devised using an isocyanate compound containing an aromatic ring structure
in the isocyanate component in order to preferentially arrange an aromatic ring structure
having superior chemical resistance in the vicinity of the urethane group or urea group.
Next, the inventors devised a polyester polyol component with superior
workability and chemical resistance and having an aromatic ring structure being
contained in a polyol component, and by these being combined, achieved the discovery
of a polyurethane resin superior in all of workability, corrosion resistance and chemical
resistance.
The polyurethane resin used in the invention having (1) containing a polyester
5 polyol component derived structural unit having an aromatic ring structure and (2)
containing an isocyanate component derived structural unit, and containing an aromatic
ring structure in all of the isocyanate component derived structural units is a prerequisite.
The contribution of (2) to chemical resistance is greater than that of (1); however, neither
of these singly is able to obtain satisfactory chemical resistance. The present invention
10 achieves chemical resistance through the synergistic effect of (I) and (2), and specifically,
as described above, increases chemical resistance to the maximum by selectively
arranging an aromatic ring structure, which is superior in chemical resistance and is able
to suppress infiltration of chemicals due to the effect of steric hindrance, in the vicinity of
the urethane group and the urea group which are easily affected by chemicals, and by
15 further arranging an ester group having moderate cohesion and an aromatic ring structure
superior in chemical resistance in a soft segment formed by a polyol component derived
constituent component.
The invention was completed on the basis of these new findings, and obtains the
finding that it is possible to secure the above-described multiple capabilities without
20 relying on the crosslinking effect due to a curing agent, in particular, even in a color
coating in which it is difficult to secure cohesion of a coating film including a color
pigment.
[00 171
Below, preferred embodiments of the invention based on the above findings will
25 be described in detail.
12
[00 1 81
The chromate-free color coated metal plate according to an embodiment of the
invention has, on at least one side of the metal plate, a color coating (a) including a film
forming component including a polyurethane resin (Al) containing a urea group, a
urethane group and a carboxyl group; a color pigment (B); and spherical silica particles
(C) with an average particle diameter of 5 to 50 nm, in which the polyurethane resin (Al)
contains, a polyester polyol component (a) derived structural unit having an aromatic ring
structure, an isocyanate component (b) derived structural unit having an aromatic ring
structure; and all of the isocyanate component (b) derived structural units contain
aromatic rings.
[00 191
More specifically, the chromate-free color coated metal plate according to the
embodiment has a color coating (a) including, as an essential component in the film
forming component of the color coating, a polyurethane resin (Al) containing a urea
group, a urethane group and a carboxyl group, and further containing a polyester polyol
component (a) derived structural unit having an aromatic ring structure, and an
isocyanate component (b) derived structural unit having an aromatic ring structure, and
contains an aromatic ring structure in all of the isocyanate component (b) derived
structural units, and further including a color pigment (B) contributing to the design
characteristics in the coated metal plate by coloring the coating film and spherical silica
particles (C) with an average particle diameter of 5 to 50 nm contributing to
improvement of the corrosion resistance and scratch resistance of the coated metal plate
formed on at least one side of the metal plate which is a base material. Since the urea
group and urethane group included in the polyurethane resin (Al) have high cohesion
energy, it is possible to achieve homogeneous film formation with sufficient coating
I 13
strength and ductility even with balung over a short period of time, as the crosslinking
and curing reaction using a curing agent is not necessarily required. The carboxyl group
included in the polyurethane resin (Al) has an effect of increasing adhesiveness with the
metal plate (subbing layer in the case of surface preparation) which is a base material.
5 In addition, it is possible to secure extremely superior workability, corrosion resistance
and chemical resistance, particularly chemical resistance, as described above, by
containing a polyester polyol component (a) derived structural unit having an aromatic
ring structure; and an isocyanate component (b) derived structural unit having an
aromatic ring structure, and containing an aromatic ririg structure in all of the isocyanate
10 component (b) derived structural units in the polyurethane resin (Al). Through these
I synergistic effects, it is possible to secure multiple capabilities, such as extremely
superior design characteristics, humidity resistance, workability, scratch resistance, and
chemical resistance.
[0020]
The chromate-fiee color coated metal plate according to the embodiment is
provided with a non-chromium coating film not including hexavalent chromium with
high environmental burden characteristics, and the non-chromium coating film may be
manufactured by forming using an aqueous color composition, rather than an organic
solvent-based color composition for which dedicated coating facilities are indispensable.
By making the color composition aqueous, design in which the polyurethane resin (Al)
used as a film forming component is also aqueous is possible. An aqueous
polyurethane resin, different to a polyurethane resin being used in the related as organic
solvent based, enables extremely high molecular weight design, and has the advantage of
being able to achieve homogeneous film formation with sufficient coating strength and
25 ductility even with baking over a short period of time, as the crosslinking and curing
4 14
reaction using a curing agent is not necessarily required. In addition, the carboxyl
group included in the structure of the polyurethane resin is an important hydrophilic
functional group in making the polyurethane resin aqueous, and is also an essential
functional group in securing the stability of the polyurethane resin in the aqueous color
5 composition. Thereby, according to the invention, it is possible to provide an
inexpensive chromate-fiee color coated metal plate with high design characteristics, and
combining humidity resistance, corrosion resistance, workability, scratch resistance, and
chemical resistance.
[002 11
10 The color coating (a) formed on the metal plate is preferably formed by coating,
heat-drying an aqueous color composition containing a coating constituent component
(the polyurethane resin (Al), the color pigment (B) and the silica particle (C)) in an
aqueous solvent on a metal plate. Here, an aqueous solvent signifies a solvent in which
the main component of the solvent is water. It is preferable that the amount of water
1 15 accounted for in the solvent be 50 mass% or more. A solvent other than water may be
I
I
I an organic solvent; however, it is preferably not one corresponding to a substance
containing an organic solvent (substance containing more than 5% by weight of an
organic solvent published in Appended Table 6-2 of the Order for the Enforcement of the
Industrial Safety and Health Law) as defined in the Ordinance On Prevention of Organic
20 Solvent Poisoning of the Japanese Industrial Safety and Health Law. By using an
aqueous solvent, since extra threading on dedicated coating lines for using organic
solvent-based coating materials is not necessary, there is also a merit, fiom an
. environmental standpoint, of also being able to suppress discharge of volatile organic
compounds (VOC), in addition to enabling reduction of manufacturing costs over a wide
25 range.
15
[0022]
The thickness of the color coating (a) is from 2 to 10 pm. The thickness of the
color coating (a) is more preferably 3 to 7 pm. When less than 2 pm, suficient design
characteristics (concealment) or corrosion resistance may not be obtained. When over
10 pm, there is not only an economic disadvantage, but coating defects such as bubbling
may occur in cases where the color coating (a) if formed fiom an aqueous color
composition, and it may not be possible to stably obtain the required appearance on a
color coated metal plate as an industrial product.
[0023]
The thickness of the color coating (a) may be measured by observation of the
cross-section of the coating or use of an electromagnetic thickness meter, or the like. In
addition thereto, the mass of the coating film attached per unit area may be measured by
dividing the specific gravity of the coating film or specific gravity after drying of the
coating solution. The attached mass of the coating film may be appropriately selected
fiom known methods, such as measuring the difference in mass before and after coating,
the difference in mass before and after peeling of the coating film after coating, or the
abundance of elements for which the content in a coated film is understood in advance by
fluorescent X-ray analysis of the coating film. The specific gravity of the coating film
or the specific gravity after drying of the coating solution may be appropriately selected
from known methods, such as measuring the volume and mass of an isolated coating film,
measuring the volume and mass of an appropriate amount of coating solution after being
taken fiom a container and dried, or calculating fiom the blending quantities of the
coating film constituent components and the known specific gravities of each component.
[0024]
Even among the various measurement methods described above, since
convenient and precise measurement is possible even in coating films differing in
specific gravity or the like, use of observation of the cross-section of the coating film is
suitable.
5 [0025]
The method of observing the cross-section of the color coating (a) is not
particularly limited; however, a method of embedding the coated metal plate in a room
temperature drying epoxy resin orthogonal to the film thickness direction, and observing
the embedding surface using an SEM (scanning electron microscope) after mechanical
10 polishng, or a method of observing the coating film cross-section using a TEM
(transmission electron microscope) after cutting, using an FIB (focused ion beam) device,
an observation sample with a thickness of 50 to 100 nrn from the coated metal plate so
that the vertical cross-section of the coating film is visible may be suitably used.
[0026]
15 The polyurethane resin (Al) including the film forming component of the color
coating (a) as an essential component contains a urea group, a urethane group and a
carboxyl group, and further contains a polyester polyol component (a) derived structural
unit having an aromatic ring structure, and an isocyanate component (b) derived
structural unit having an aromatic ring structure, and is not particularly limited if
20 containing an aromatic ring structure in all of the isocyanate component (b) derived
structural units, for example, a compound obtained by a urethane prepolymer, obtained
by causing a urethane forming reaction of a polyol compound including a polyester
polyol component having an aromatic ring structure and an isocyanate compound having
an aromatic ring structure in conditions of an excess of an isocyanate group included in
25 an isocyanate compound, being further reacted with a polyamine compound and
undergoing chain elongation may be used. Through such a manufacturing method, it is
possible to generate a urethane group by reaction of a hydroxyl group included in a
polyol compound and an isocyanate group included in an isocyanate compound, generate
a urea group by reaction of an amino group included in a polyamine compound and an
5 isocyanate group included in an isocyanate compound, and manufacture an ultrahigh
molecular weight polyurethane resin containing a urea group and a urethane group.
[0027]
The polyol compound indicates a compound containing two or more hydroxy
groups per molecule, and a polyol compound including a polyester polyol component (a)
10 having an aromatic ring structure (hereinafter, referred to as aromatic polyester polyol
(a)) as an essential component is used in the invention.
[0028]
The aromatic polyester polyol (a) may be obtained by condensation reaction
using a known method of a raw material composition including derived structural units
15 of either or both of an aromatic polyvalent carboxylic acid and an aromatic polyvalent
alcohol, and including either or both of an aromatic polyvalent carboxylic acid and an
aromatic polyvalent alcohol.
[0029]
The aromatic polyvalent carboxylic acids include aromatic bivalent carboxylic
20 acids or trivalent or higher-valent aromatic carboxylic acid or the like, and examples of
the divalent carboxylic acid include, for example, terephthalic acid, isophthalic acid,
orthophthalic acid, naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid,
2,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, naphthalic acid
(naphthalene-1,s-dicarboxylic acid), biphenyl dicarboxylic acid, 1,2-bis (phenoxy)
25 ethane-p, p'-dicarboxylic acid or the like, or aromatic carboxylic acids or acid anhydrides
or ester forming derivatives thereof, aromatic hydroxy carboxylic acids, such as
p-hydroxy benzoic acid or ester-forming derivatives thereof, as well as sulfonate
group-containing aromatic dicarboxylic acids, such as 5-sulfoisophthalic acid or
ester-forming derivatives thereof These aromatic divalent carboxylic acids may be
5 substitution products in which various substituents are substituted.
[003 01
Examples of the above trivalent and higher-valent aromatic carboxylic acids
include, for example, aromatic polyvalent carboxylic acids, such as trimellitic acid and
I pyromellitic acid, or acid anhydrides or ester forming derivatives thereof. These
10 trivalent or higher-valent aromatic carboxylic acids may be substitution products in
I
I which various substituents are substituted. The aromatic polyvalent carboxylic acid
I
I may be only one type used singly, or two or more types may be used together.
[003 11
The aromatic polyester polyol (a) may contain polyvalent carboxylic acid
15 derived structural units other than an aromatic polyvalent carboxylic acid. Examples of
the polyvalent carboxylic acids other than aromatic polyvalent carboxylic acids include,
for example, aliphatic dicarboxylic acids such as succinic acid, adipic acid, suberic acid,
azelaic acid, sebacic acid, dimer acid, maleic acid, fbmaric acid or acid anhydrides or
ester-fonning derivatives thereof; and alicyclic dicarboxylic acids, such as
20 1,4-cyclohexanedicarboxylic acid or acid anhydrides or ester-forming derivatives thereof
These divalent carboxylic acids may be substitution products in which various
substituents are substituted. The polyvalent carboxylic acid other than an aromatic
polyvalent carboxylic acid may be only one type used singly, or two or more types may
be used together.
25 [0032]
Examples of aromatic polyvalent alcohols include, for example, bisphenol A,
bisphenol S, hydroxine, bis-hydroxyethoxy benzene, and alkylene oxide adducts, or the
llke. These aromatic polyvalent alcohols may be substitution~productisn which various
substituents are substituted. The aromatic polyvalent alcohol may be only one type
5 used singly, or two or more types may be used together.
[0033]
The aromatic polyester polyol (a) may contain polyvalent alcohol derived
structural units other than an aromatic polyvalent alcohol. Examples of polyvalent
alcohols other than aromatic polyvalent alcohols include, for example, aliphatic diols,
10 such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol,
1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol,
triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol,
polyethylene glycol, 3-methyl-1,5-pentanediol, or 2-butyl-2-ethyl-1,3-propanediol;
alicyclic diols, such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, or
15 hydrogenated bisphenol A; aliphatic or alicyclic polyvalent alcohols, such as glycerin,
trimethylol propane, or pentaerythritol; and aliphatic polyvalent alcohols obtained by
ring-opening polymerization of cyclic esters, such as E-caprolactone, or y-valerolactone.
These polyvalent alcohols may be substitution products in which various substituents are
substituted. The polyvalent alcohols other than an aromatic polyvalent alcohol may be
20 only one type used singly, or two or more types may be used together.
[0034]
The content ratio of the structural units derived from aromatic polyvalent
carboxylic acids, polyvalent carboxylic acids other than aromatic polyvalent carboxylic
acids, aromatic polyvalent alcohols, and polyvalent alcohols other than aromatic
25 polyvalent alcohols configuring the aromatic polyester polyol (a) being adjusted such that
v 20
the aromatic ring structure included in the aromatic polyester polyol (a) is contained in
the polyurethane resin (Al) at 5 to 25 mass% is preferable from the viewpoint of
workability or chemical resistance, and is more preferably 15 to 20 mass%. If less than
5 mass%, there are cases where the chemical resistance is lowered; and when higher than
5 25 mass%, there are cases where the workability is lowered.
[003 51
In the polyurethane resin (Al), the content ratio of the aromatic ring structure
included in the aromatic polyester polyol (a) is calculated by the following Formula [I].
Content ratio (mass%) of the aromatic ring structure = 100 x [{mol number
10 (mol) of aromatic polyvalent carboxylic acids configuring aromatic polyester polyol (a) x
number (units) of aromatic ring structures in 1 molecule of aromatic polyvalent
carboxylic acid x molecular weight of aromatic ring part (g/mol)) + {mol number (mol)
of aromatic polyvalent alcohol configuring aromatic polyester polyol (a) x number
(units) of aromatic ring structures in 1 molecule of aromatic polyvalent alcohol x
15 molecular weight of aromatic ring parts (g/mol))] / {mass (g) of solids of polyurethane
resin (Al)) ... [l]
[003 61
Here, "molecular weight of aromatic ring parts" is not the molecular weight as
an aromatic ring residue having an aromatic polyester polyol (a), but is the molecular
20 weight in a case of the residue being present in an isolated aromatic ring compound, and
further, a substituent having an aromatic ring structure (excepting the aromatic ring) is
not included in the molecular weight. For example, for the "molecular weight of the
aromatic ring parts" in a case of using an alkyl substituted terephthalic acid as the
aromatic polyvalent carboxylic acid, the molecular weight of a benzene ring is 78.11.
v 21
In the case of using two or more aromatic polyvalent carboxylic acids, the (mol number
(mol) of aromatic polyvalent carboxylic acids configuring aromatic polyester polyol (a) x
number (units) of aromatic ring structures in 1 molecule of aromatic polyvalent
carboxylic acid x molecular weight of aromatic ring part (glmol)) in the above Formula
5 [l] is the sum calculated for each aromatic polyvalent carboxylic acid. The same
applies to a case of using two or more aromatic polyvalent alcohols.
[003 71
The polyol component may include a polyol component other than the aromatic
polyester polyol (a). As such polyol compounds, macropolyols, such as polyester
10 polyol or polycarbonate polyol not including an aromatic ring structure, such as aliphatic
and alicyclic polyester polyol, polyether polyol, polyester amide polyol, acrylic polyol, or
polyurethane polyol; aliphatic diols, such as ethylene glycol, propylene glycol,
1,3 -propanediol, 1,3 -butanediol, 1,4-butanediol, 1,5 -pentanediol, 1,6-hexanediol,
neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene
15 glycol, tripropylene glycol, polyethylene glycol, 3-methyl-l,5-pentanediolo, r
2-butyl-2-ethyl-l,3-propanediol; alicyclic diols, such as 1,4-cyclohexanediol,
1,4-cyclohexanedimethanol,o r hydrogenated bisphenol A; aliphatic or alicyclic
polyvalent alcohols, such as glycerin, trimethylol propane, or pentaerythritol; and
aliphatic polyvalent alcohols obtained by ring-opening polymerization of cyclic esters,
20 such as E-caprolactone, or y-valerolactone, or mixtures thereof may be used. The
aliphatic and alicyclic polyester polyol may be prepared using a polyvalent carboxylic
other than the aromatic polyvalent carboxylic acid and a polyvalent alcohol other than the
aromatic polyvalent alcohol.
COO3 81
2 5 As the isocyanate compound, an isocyanate compound having an aromatic ring
structure (hereinafter, referred to as aromatic isocyanate (b)) is used. .Specific examples
of the aromatic isocyanate (b) include, for example, 1,3-, or 1,4-a, a, a', a'-tetramethyl
xylylene diisocyanate, m-xylene diisocyanate, m-phenylene diisocyanate, p-phenylene
diisocyanate, 4,4'-diphenyl diisocyanate, 1,5 -naphthalene diisocyanate,
5 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate,
4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
I 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4,4'-diphenyl diisocyanate or the
like. These may be only one type used singly, or two or more types may be used
together. From the viewpoint of chemical resistance, using tolylene diisocyanate is
preferable.
[003 91
The aromatic ring structure included in the isocyanate component (b) having an
aromatic ring structure being adjusted so as to be contained at 5 to 20 mass% in the
polyurethane resin (Al) is preferable from the viewpoint of workability or chemical
resistance, and more preferably 10 to 15 mass%. If less than 5 mass%, there are cases
where the chemical resistance is lowered; and when higher than 20 mass%, there are
cases where the coating film is cured and workability is lowered.
[0040]
In the polyurethane resin (Al), the content ratio of the aromatic ring structure
included in the aromatic isocyanate (b) is calculated by the following Formula [2].
content ratio of aromatic ring structure (mass%) = 100 x (mol number (mol) of
aromatic isocyanate (b) x number (units) of aromatic ring structures in 1 molecule of
aromatic isocyanate (b) x molecular weight of aromatic ring parts (gjmol)) 1 mass (g) of
solids of polyurethane resin (Al)} . . . [2]
Here, "molecular weight of aromatic ring parts" is not the molecular weight as
an aromatic ring residue having an aromatic isocyanate (b), but is the molecular weight in
a case of the residue being present in an isolated aromatic ring compound, and further,
5 the substituent having an aromatic ring structure (excepting the aromatic ring) is not
included in the molecular weight. For example, the "molecular weight of the aromatic
ring parts" in a case of using tolylene diisocyanate as the aromatic isocyanate (b), the
molecular weight of a benzene ring is 78.11. In the case of using two or more aromatic
isocyanates (b), the (mol number (rnol) of aromatic isocyanate (b) x number (units) of
10 aromatic ring structures in 1 molecule of aromatic isocyanate (b) x molecular weight of
aromatic ring part (glmol)) in the above Formula [2] is the sum calculated for each
aromatic isocyanate (b). The same applies to a case of using two or more aromatic
isocyanates (b).
[0042]
15 Apolyamine compound known in the related art may be used. Examples of the
ipolyamine compound include, for example, polyamine compounds having diamino
sulfonates, such as N-(2-sulfoethyl) ethylenediamine metal salts, or
2-(P-amino-alkyl-amino-propionamide) alkane sulfonate, aliphatic primary diamines,
such as ethylenediamine and an anionic group, such as a-olefin based carboxylic acid
20 adducts, such as (meth)acrylate; diamines, such as 1,2-diaminoethane, 1,2-or
1,6-diaminohexane, piperazine, N,N1-bis-(2-aminoethyl) piperazine, 1-amino-3-amino
methyl 3,5,5-trimethyl-cyclohexane (isophorone diamine), bis-(4-aminocyclohexyl)
methane, bis-(4-amino-3-butyl cyclohexyl) methane, 1,2-, 1,3- or
1,4-diaminocyclohexane, 1,3-diaminopropane, in addition to polyamines not having an
anionic group, such as hydrazine derivatives, such as hydrazine and adipic acid
dlhydrazide; or polyarnines, such as diethylenetriamine or triethylenetetramine.
[0043]
5 The polyurethane resin (Al) containing a carboxyl group is a prerequisite. The
method of introducing the carboxyl group into the polyurethane resin (Al).is not
particularly limited; however, for example, examples include methods in which one or
two or more types of compounds containing a carboxyl group or derivatives thereof, such
as 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid, 2,2-dimethylol valeric acid,
10 dioxy maleic acid, 2,6-dioxy-benzoic acid, 3,4-diamino benzoic acid, or polyester polyols
obtained by copolymerization thereof; carboxyl group-containing compound reacted
fiom anhydride group-containing compounds and compounds having active hydrogen
groups, or derivatives thereof, such as maleic anhydride, phthalic anhydride, succinic
anhydride, trimellitic anhydride, pyromellitic dianhydride, or a polyester polyol obtained
15 by cop~lymerizationth ereof; are polymerized during the manufacture of a urethane
prepolymer.
[0044]
The carboxyl group included in the polyurethane resin (Al), in addition to
having an effect of increasing adhesiveness with the metal plate (subbing layer in the
20 case of surface preparation) which is a base material, contributes significantly to the
dispersibility or stability in the aqueous medium in a case where the polyurethane resin
(Al) is aqueous. In order to improve the dispersibility or stability in the aqueous
medium, the carboxyl group may be neutralized by a neutralizing agent. The
neutralizing agent is not particularly limited and examples include, for example, tertiary
25 mines, such as ammonia, triethylamine, triethanolamine, triisopropanolamine,
trimethylamine, dimethylethanolamine; alkali metal, such as sodium hydroxide,
potassium hydroxide, calcium hydroxide; or basic substances, such as hydroxides of
alkaline-earth metals; however, from the viewpoint of film formability of the color
coating (a) and stability of the aqueous color composition for forming the color coating
(a), it is preferable that alkanolamines -with a boiling point of 150°C or lower, such as
triethanolamine, and dimethylethanolamine be used. These neutralizing agents may be
used individually and may also be used in a mixture of two or more types. As the
method of adding the neutralizing agent, the agent may be directly added to the urethane
prepolymer, or may be added in an aqueous solvent when dissolved or dispersed in an
aqueous solvent. The addition amount of the neutralizing agent is preferably 0.1 to 2.0
equivalent weight with respect to the carboxyl group, and more preferably 0.3 to 1.3
equivalent weight.
[004 51
The content ratio of the carboxyl group contained in the polyurethane resin (Al)
is not particularly limited; however it is preferable that the amount exhibit an acid value
in a range of 0.1 to 50 mg KOWg. If less than 0.1 mg KOWg the effect improving the
adhesiveness between the color coating (a) and the base material metal plate (subbing
layer in a case of surface preparation), and further, there are cases where the dispersibility
or stability in the aqueous medium is insufficient in a case where the polyurethane resin
(Al) is aqueous. If exceeding 50 mg KOWg, the corrosion resistance or chemical
resistance of the color coated metal plate may be lowered. If the balance of capabilities
is considered, being in the range of 0.5 to 25 mg KOWg is more preferable.
[0046]
In a case where the polyurethane resin (Al) is aqueous, "...is aqueous" indicates
"...is water-soluble or water dispersible". Water-soluble or water dispersible indicates
, -
that, when the polymer is to be dissolved in water at a concentration of 1 mass%, when
allowed to stand at 25OC for 24 hours after the effort of homogenizing by heating and
stirring, the polymer does not precipitate, phase separation does not occur and the
solution is uniform. The definition of "...being aqueous" is applied to resins (details
5 described later) other than polyurethane resin (Al) used in the invention.
[0047]
In the color coating (a),fu rther containing a polyester resin (A2) containing a
sulfonate group other than the polyurethane resin (Al) as the coating film forming
composition is preferable in terms of increasing workability or chemical resistance. The
10 polyester resin (A2) may be obtained through condensation polymerization of a polyester
raw material formed from a polycarbonate component and a polyol component. In
addition, in a case where the color composition for forming the color coating (a) is
aqueous, it is possible to use one made aqueous through dissolving or dispersing of the
polyester resin in water thereby obtained.
[0048]
Examples of the polycarbonate component include, for example, phthalic acid,
phthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride,
hexahydrophthalic acid, hexahydrophthalic anhydride, tetra methyl phthalic acid, methyl
tetrahydrophthalic anhydride, himic acid anhydride, trimellitic acid, trimellitic anhydride,
pyromellitic acid, pyromellitic anhydride, isophthalic acid, terephthalic acid, maleic acid,
maleic anhydride, fbmaric acid, itaconic acid, adipic acid, azelaic acid, sebacic acid,
succinic acid, succinic anhydride, lactic acid, dodecenylsuccinic acid, dodecenylsuccinic
anhydride, cyclohexane-1,4 dicarboxylic acid, endic anhydride, or the like. One type of
the polycarbonate component may be used, or a plurality of types may be used.
[0049]
1 Examples of the polyol component include, for example, ethylene glycol,
1 diethylene glycol, 1,3-propanediol, 1,2-propanediol, triethylene glycol, 2-methyl-1,3
propanediol, 2,2-dimethyl- 1,3 propanediol, 2-butyl-2-ethyl-1,3-propanediol,
I,$-butanediol, 2-methyl-l,4-butanediol,2 -methyl-3-methyl- l,4-butanediol,
5 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol,
1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol,h ydrogenated bisphenol-A,
dimer diol, trimethylol ethane, trimethylol propane, glycerin, pentaerythritol, or the like.
One type of the polyol component may be used, or a plurality of types may be used.
[0050]
The polyester resin (A2) contains a sulfonate group in the resin structure. The
sulfonate group has an effect increasing dispersibility to a coating liquid of a color
pigment having a hydrophobic surface, in addition to increasing adhesiveness between
the color coating (a) and the base material metal plate (subbing layer (P) in the case of
surface preparation) The method of introducing the sulfonate group to the polyester
resin is not particularly limited, and examples include, for example, methods using
dicarboxylic acids, such as 5-sulfoisophthalic acid, 4-sulfonaphthalene- 2,7-dicarboxylic
acid, 5-(4-sulfophenoxy) isophthalic acid; or glycols, such as 2-sulfo-l,4-butanediol,
2,5-dimethyl-3-sulfo-2,5-hexyld iol as a polyester raw material.
[005 11
A sulfonate group indicates a functional group represented by -S03H, and the
sulfonate group may be one neutralized by an alkali metal, an mine including ammonia
or the like. In the case of neutralizing, an already neutralized sulfonate group may be
combined in the resin, or may be neutralized after the sulfonate group is combined in the
resin. In particular, metal sulfonate groups neutralized by alkali metals, such as Li, Na
or K, are preferable in terms of increasing dispersibility to the coating liquid of a color
pigment having a hydrophobic surface, addition to increasing adhesiveness between the
color coating and the base material metal plate, and Na sulfonate groups are particularly
preferable.
[0052]
5 The usage amount of the dicarboxylic acid containing a sulfate group or glycol
used for introducing a sulfonate group to the polyester resin (A2) is preferably 0.1 to 10
mol% with respect to all polycarbonate components or all polyol components. If less
than 0.1 mol%, the effect of improving the adhesiveness of the color coating to tha base
material metal plate may not be obtained, and further, in the case where an aqueous
solvent is used, the solubility or dispersibility of the polyester resin (A2) with respect to
water may be lowered, and further the design characteristics of the formed color coating
may be lowered. If exceeding 10 mol%, the corrosion resistance of the color coated
metal plate may be lowered. If the balance of capabilities is considered, being in the
range of 0.5 to 7 mol% is preferable.
[0053]
It is preferable that the polyester resin (A2) contain a bisphenol group in the
resin structure. Since the bisphenol group is excellent in waterproofhess in addition to
having a high cohesion energy, the polyester resin (A2) including a bisphenol group is
preferable in terms of improving the scratch resistance and corrosion resistance of the
color coated metal plate. The method of introducing the bisphenol group to the
polyester resin (A2) is not particularly limited, and examples include, for example,
methods using glycols, such as ethylene oxide adduct of bisphenol A, propylene oxide
adduct of bisphenol A, ethylene oxide adduct of bisphenol F, or propylene oxide abduct
of bisphenol F as a polyester raw material.
[0054]
The usage amount of the glycol containing a bisphenol group as above is
preferably 1 to 40 mol% with respect to all polyol components. If less than 1 mol%, the
effect of improving the scratch resistance or corrosion resistance of the color coated
metal plate may not be obtained. If exceeding 40 mol%, the workability of the color
5 coated metal plate may be lowered. If the balance of capabilities is considered, being in
the range of 5 to 30 mol% is preferable.
For the content ratio of the polyester resin (A2), a mass ratio of polyurethane
resin (Al) 1 polyester resin (A2) being 10190 to 90110 is preferable, and 25/75 to 75/25 is
more preferable. If less than 10190, there are cases where the corrosion resistance or
scratch resistance is lowered; and when higher than 90110, there are cases where the
effect of improving the workability or chemical resistance is lowered.
[0056]
It is preferable that an acrylic resin (A3) other than the polyurethane resin (Al)
be contained as a coating film forming component (a). By containing an acrylic resin,
the adhesiveness to the metal plate which is the base material (subbing layer in the case
of surface preparation) improves, and the scratch resistance improves. In addition, the
color pigment (B) is a pigment having a hydrophobic surface such as carbon black (B 1)
(described later), in a case where the color composition for forming the color coating (a)
is aqueous, the pigment is uniformly dispersed in the aqueous solvent, and in addition to
contributing superior design characteristics to the formed color coating (a), the acrylic
resin (A3) may be suitably contained.
[0057]
The acrylic resin (A3) is not particularly limited, and examples that may be used
include, for example, ethylenically unsaturated carboxylic acid alkyl ester monorqers,
* 30
such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate,
ethylhexyl-2-(meth)acrylate singly or as copolymers of two or more kinds thereof; and
further, ethylenically unsaturated carboxylic acid alkyl ester monomers, such as acrylic
acid, methacrylic acid, maleic acid, itaconic acid; ethylenically unsaturated carboxylic
acid monomers, such as methyl (meth)acrylate; ethyl (meth)acrylate, n-butyl
(meth)acrylate, ethylhexyl-2-(meth)acrylate; ethylenically unsaturated dicarboxylic acid
monoester monomers, such as ethyl maleate, butyl maleate, ethyl itaconate, butyl
itaconate; hydroxyl group-containing ethylenically unsaturated carboxylic acid alkyl
ester monomers, such as hydroxyethy1,-2-(meth)acrylate,
hydroxypropyl-2-(meth)acrylate, hydroxybuty1,-4-(meth)acrylate, reactants with
hydroxyethyl-2-(meth)acrylate and E-caprolactone; ethylenically unsaturated carboxylic
acid amino alkyl ester monomers, such as aminoethyl (meth)acrylate,
dimethylaminoethyl (meth)acrylate, butylaminoethyl (meth)acrylate; ethylenically
unsaturated carboxylic acid aminoalkyl amide monomers, such as arninoethyl
(meth)acrylamide, dimethylaminomethyl (meth)acrylamide, methylamino-propyl
(meth)acrylamide; other amide group-containing ethylenically unsaturated carboxylic
acid monomers, such as acrylamide, methacrylamide, N-methyl01 acrylamide, methoxy
butyl acrylamide, diacetone acrylamide; unsaturated fatty acid glycidyl ester monomers,
such as glycidyl acrylate, glycidyl methacrylate; vinyl cyanide monomers, such as
(meth)acrylonitrile, a-chloro-acrylonitrile; saturated aliphatic carboxylic acid vinyl ester
monomers, such as vinyl acetate, vinyl propionate; styrene monomers, such as styrene,
a-methyl styrene, vinyl toluene, singly or as copolymers of two or more types the eof. 1
The polymerization method of these monomers is not particularly limited; and exahples
include, for example, those obtained by a method of radical polymerization of these
monomers using a polymerization initiator. The polymerization initiator is not
~
particularly limited, and, for example, persulfates, such as potassium persulfate or ~
ammonium persulfate; or azo compounds, such as azobis cyanovaleric acid or
azobisisobutyronitrile may be used. The monomers used in synthesizing the acrylic
resin may be used singly, or two or more components may be used together.
The content ratio of the acrylic resin (A3) is preferably 0.5 to 20 mass% with
respect to 100 mass% of the polyurethane resin (Al) (in a case of including the polyester
resin (A2) in the film forming component of the color coating (a), the total amount of
polyurethane resin (Al) and polyester resin (A2)), is more preferably 1 to 15 % by mass,
10 and particularly preferable 2 to 10 mass%. If less than 0.5 mass%, there are cases
where the effect improving the design characteristics (colorability, concealment) is not
I obtained; and when higher than 20 mass%, there are cases where the corrosion resistance
or workability of the coating film is lowered.
[0059]
The polyurethane resin (Al) (in the case of including the polyester resin (A2) or
acrylic resin (A3) in the film forming component of the coating film (a), the resins
thereof), in improving the scratch resistance or corrosion resistance of the color coated
metal plate, is preferably a resin cured using a curing agent (D). The curing agent (D) is
not particularly limited if able to cure the resin (A) described above, and examples
include, for example, a melamine resin or polyisocyanate compound. The melamine
resin is a resin of a product obtained by condensation of melamine and formaldehyde, in
which a part of all of the methyl01 group is etherified by a lower alcohol such as
methanol, ethanol or butanol. The polyisocyanate compound is not particularly limited,
and examples include, for example, hexamethylene diisocyanate, isophorone
diisocyanate, xylylene diisocyanate, or tolylene diisocyanate. A blocked material of the
polyisocyanate compound may be used, and, examples include, for example, a blocked
material of hexaxylene diisocyanate which is a blocked material of a polyisocyanate
compound, a blocked material of isophorone diisocyanate, a blocked material of xylylene
diisocyanate, or a blocked material of tolylene diisocyanate. The curing agent (D) may
5 use one type, or two or more types together.
[0060]
The usage amount of the curing agent @) is preferably 5 to 35 mass% with
respect to 100 mass% of the polyurethane resin (Al) (in the case of including the
polyester resin (A2) or acrylic resin (A3) in the film forming component of the coating
10 film (a), the resins thereof). If less than 5 mass%, the baking and curing of the coating
film is insufficient, and the corrosion resistance and scratch resistance of the color coated
metal plate may be lowered; when exceeding 35 mass%, the baking and curing of the
coating film is excessive, and there are cases where the corrosion resistance or
workability of the color coated metal plate is lowered.
From the viewpoint of scratch resistance, the curing agent (D) preferably
contains a melamine resin. The content ratio of the melamine resin in the curing agent
(D) is preferably 30 to 100 mass%. If less than 30 mass%, the effect of improving the
scratch resistance may not be obtained.
The color pigment (El) contained in the color coating (a) of the chromate+fiee
color coated metal plate according to the embodiment is a component imparting a ~
predetermined color and providing sufficient concealment to the coating film. ~
Examples of representative color pigments that may be used in the present invention
25 include, colored inorganic pigments, such as carbon black, titanium dioxide, grap1 it e,
iron oxide, lead oxide, coal dust, talc, cadmium yellow, cadmium red, chrome yellow;
colored organic pigments, such as phthalocyanine blue, phthalocyanine green,
quinacridone, perylene, anthracite pyrimidine, carbazole violet, anthrapyridine, azo
orange, flavanthrone yellow, isoindoline yellow, azo yellow, indanthrone blue,
dibromoanthrathrone red, perylene red, azo red, anthraquinone red; radiant materials,
such as aluminum powder, alumina powder, bronze powder, copper powder, tin powder,
zinc powder, iron phosphide powder, metal coating mica powder, titanium dioxide,
coating mica powder, titanium dioxide coating glass powder, or the like.
[0063]
In a case where carbon black is used as the color pigment (B), there is no .
particular limitation and, for example, known carbon blacks, such as furnace black,
ketjen black, acetylene black or channel black may be used. In addition, carbon black
treated by a known ozone treatment, plasma treatment, or liquid phase oxidation
treatment may also be used. A carbon black with a primary particle diameter of 10 to
120 &I is preferably used, in consideration of dispersibility in the aqueous color
composition, coatability and coating film quality. A thin film, if considering the design
characteristics (colorability, concealment) or corrosion resistance of, for example, a thin
film of approximately 10 pm or less, preferably uses a carbon black with fine particles
with a primary particle diameter of 10 to 50 nm. On the other hand, since aggregation
occurs in a process of dispersing carbon black in a dispersion medium (water), dispersion
is normally difficult with the primary particle diameter. In other words, in practice, the
carbon black is present in the aqueous color composition in the form of secondary ~
particles having a particle diameter larger than the primary particle diameter, and ib
present in a similar form in the coating film formed fkom the paint color composition.
In order to secure the design characteristics (colorability, concealment) or corrosion
resistance in a thin film, the particle diameter of the carbon black dispersed in the coating
film is important, and the average particle diameter of the secondary particles is
preferably 20 to 300 nm. The average particle diameter of the carbon black secondary
particles is more preferably 30 to 250 nm, and even more preferably 50 to 200 nm.
5 [0064]
Carbon black is a color pigment with excellent concealment. Therefore, if
using carbon black as the color pigment (I3), it is effective in making the film thickness
of the formed color coating (a) thinner.
[0065]
10 In order to secure the design characteristics (colorability, concealment) of the
coating film through the carbon black, ensuring the absolute amount of the carbon black
included in the color coating (a) at a fixed amount or higher is important. The absolute
amount of carbon black may be represented as the product (X x Y) of the content ratio (X
mass%) of the carbon black included in the coating film and the coating film thickness
15 (Y pm). If X x Y is less than 20, the design characteristics (colorability, concealment)
may be lowered. If X exceeds 15, the film forming characteristics of the coating film
are lowered, and the corrosion resistance or workability may be lowered. In other
words, it is preferable that the carbon black and the coating film satisfy a relationship of
X 5 12 is even more preferable.
[0066]
In the case where a color pigment other than carbon black is used, the colbr
pigment particles in the coating film, without concern as to whether it is the primary
particles or the secondary particles, preferably have an average particle diameter of the
above-described 20 to 300 nm of the carbon black secondary particles. More preferable
is an average particle diameter of 30 to 250 nm, and even more preferable is 50 to 200
nm.
[0067]
5 The spherical silica particles (C) with an average particle diameter of 5 to 50 nm
contained in the color coating (a) of the chromate-free color coated metal plate according
to the invention are an effective component in contributing sufficient corrosion resistance
and scratch resistance to the color coating (a). In the invention, "spherical" is not only
a true sphere, but also indicates shapes approximating a sphere, and also includes
10 elliptical bodies. Herein, in the case of an elliptical body, the ratio of the long diameter
to the short diameter being 0.7 or higher is preferable from the viewpoint of workability,
corrosion resistance and scratch resistance, and is more preferably 0.8 or higher. The
spherical silica particles (C) are not particularly limited, and using silica fine particles of
colloidal silica or the like is preferable. Examples of commercially available products
15 include, for example, Snowtex 0, Snowtex N, and Snowtex C, (made by Nissan
Chemical); and Adelite AT-20N and AT-20A (made by Asahi Denka). The more
preferable average particle diameter of the spherical silica particles (C) is 8 to 30 m, and
even more preferable is 10 to 20 nm.
[006 81
20 It is preferable that the spherical silica particles (C) be present in the color
coating (a) at 3 to 30 mass%. If the content ratio of the spherical silica particles ((C) is
less than 3 mass%, the corrosion resistance and scratch resistance of the coating film may
be insufficient if exceeding 30 mass%, the humidity resistance, corrosion resistance,
workability of the coating film may be lowered. The more preferable content ratio of
25 the spherical silica particles (C) in the coating film is 5 to 20 mass%, and even more
* preferable is 7 to 15 mass%.
The color coating (a) of the chromate-free color coated metal plate according to
the embodiment may further contain a lubricant (E), in addition to the film forming
5 component, the color pigment (B) and the silica particles (C). By containing the
lubricant (E), the scratch resistance of the coating film (a) is improved. The lubricant
(E) is not particularly limited, and known lubricants may be used; use of at least one type
~ selected fiom a fluororesin series or a polyolefin resin series is preferable. As the
~ fluororesin-based lubricant, polytetrafluoroethylene (PTFE),
I 10 tetrafluoroethylene-hexafluoropropylene copolymer (FEP), I
tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polychloro
trifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF),
I i ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene
1 copolymer (ECTFE) or the like may be used. Only one type may be used singly, or two
, 15 or more types may be used together.
The polyolefin-based lubricant is not particularly limited, and examples include
hydrocarbon-based waxes, such as parafin, microcrystalline wax, or polyethylene, and
derivatives thereof; however polyethylene resin is preferable. The derivatives are not
20 - particularly limited, and examples include, for example, carboxylated polyolefin, or
I chlorinated polyolefin. One type may be used singly, or two or more types may be used
together. In a case of using the polyethylene resin, dispersion of particles with an
average particle diameter of 0.5 to 2 pm in the color coating (a) is preferable from the
viewpoint of corrosion resistance and scratch resistance.
I
.,-
The content ratio of the lubricant (E) is preferably from 0.5 to 10 mass% in the
color coating (a),an d is more preferably from 1 to 5 mass%. If less than 0.5 masls%,
there are cases where the scratch resistance is lowered; and when higher than 10 mass%,
there are cases where the corrosion resistance or workability is lowered.
[0072]
In the color coating (a) of the chromate-free color coated metal plate of the
invention, the color pigment (B) and the spherical silica particles (C) are present a$ a
particle-like component. In addition thereto, a lubricant (E) may be present as
necessary.
[0073]
Ordinarily, it is extremely difficult to specify the shape or size of particles
included in a thin coating film. Yet, the particle component included in the coating
material (solution or dispersion (color composition) containing structural component of a
coating film) used in forming the coating film, as long as not suffering any physical or
chemical modification (for example, boding or aggregation of particles to one another,
intentional dissolving in a coating solvent, reaction with other constituent components, or
the llke) in the forming process of the coating film, even after forming the coating film,
may be considered as holding the shape or size when present in the coating material.
The color pigment (B), spherical silica particles (C) and lubricant (E) which are the
particle component used in the invention are selected so as not to intentionally dis$olve in
the solvent of the color composition used in formation of the coating film of the
invention, and not to react with the solvent or the other coating film constituent 1
I
components: In addition, with the object of increasing retention of the presence form of
these particle components in the color composition, and an already known dispersmt,
such as a surfactant or water-soluble resin, disp- ersed in the aqueous medium may be used
as a raw material of the color composition as needed. Accordingly, the particle ~
diameter of these particle components included in the coating film stipulated in th$
invention may be represented by the particle diameters thereof in the color composlition
used in formation of the coating film.
5 [0074]
More specifically, the diameter of the comparatively fine particles, such as the
color pigment (l3) or spherical silica particles (C) is measured by a dynamic light ~
I
scattering method (a method applying 'Nanotrack"). According to the dynamic ight
scattering method, the diameter of the fine particles in a dispersion medium for which the
10 temperature, viscosity and refractive index are known may be simply measured. Since
the particle component used in the invention is selected so as not to be intentionally
dissolved in the solvent of the coating material, and not to react with the solvent or the
other coating film constituent components, the particle diameter is measured in a
predetermined dispersion medium, and may be employed as the particle diameter of the
15 particle component in the color composition. In the dynamic light scattering method,
laser light is irradiated to particles dispersed in a dispersion medium and undergoing
Brownian motion, scattered light fi-om the particles is detected, the autocorrelation
function is calculated by a photon correlation method, and the particle diameter
calculated using the cumulant method. As a particle diameter measuring device using
20 the dynamic light scattering method, for example, an FPAR-1000 manufactured by
Otsuka Electronics Co., Ltd. may be used. In the invention, the cumulant average
particle diameter is calculated by measuring a dispersion sample containing particles
which are the measurement target at 25OC, the average value of a total of five
measurements is taken as the average particle diameter of the particles. The
25 measurement of the average particle diameter using the dynamic light scattering qethod
is disclosed in, for example, The Journal of Chemical Physics, Volume 57, Issue 11
(December, 1972), page 48 14.
On the other hand, the lubricant (E) or the like, may employ a particle diameter
5 with an integrated value of 50% in the particle size distribution measured using a laser
diffraction and scattering method (a method applying "Microtrac") as a comparatively
large particle diameter. The laser diffraction and scattering methods use that the mount
of scattered light scattered and the pattern differ by particle diameter when light is
irradiated on particles, and are widely used for measuring particle diameter from the
10 submicron region to approximately several millimeters. Even in this case, since the
particle component used in the invention is chosen so as to not intentionally dissolve in
the solvent of the color composition and not to react with the solvent and other color
coating constituent components, and may employ the measured particle diameter as the
particle diameter of the particle-like component in the color composition. In
15 measurement using the laser diffraction and scattering methods, for example, a Microtrac
particle size analyzer manufactured by Nikkiso Co., Ltd. may be used. In the invention,
the average value of a total of five measurements of is taken as the average particle
diameter of the particles.
[0076]
20 In addition, for the particle-like component (color pigment (l3) and spherical
silica particles (C) which essential components, and lubricant (E) which is an arbitrary
component) in the color coating (a), it is also possible to observe the color coatin8 (a) in
cross-section, and directly measure the shape and particle diameter thereof. In a case
where the particles are not true spheres, the long diameter and the short diameter of the
25 particles are respectively measured, and the average value thereof may be employed as
the particle diameter. The method of observing the cross-section of the color coa4ing
(a) is not particularly limited; however, a method of embedding the coated metal plate in
a room temperature drying epoxy resin orthogonal to the film thickness direction, md
observing the embedding surface using an SEM (scanning electron microscope) afier
mechanical polishing, or a method of observing the coating film cross-section using a
TEM (transmission electron microscope) after cutting, using an FIE3 (focused ion beam)
device, an observation sample with a thickness of 50 to 100 nm from the coated mqtal
plate so that the vertical cross-section of the coating film is visible may be suitably used.
[0077]
The color coating (a) of the chromate-free color coated metal plate according to
the invention may be formed by coating, heat-drying a color composition including the
polyurethane resin (Al), the color pigment (B) and the silica particles (C), which are the
constituent components thereof, in a solvent on at least one surface of a metal plate.
The color composition is preferably a composition in which water is the solvent, or a
composition in which the main component of the solvent is water, that is, an "aqueous
color composition" as defined earlier.
[0078]
The constituent components of the color composition may include the arbitrary
constituent components (polyester resin (4 acrylic resin (4l,ub ricant (E)) described
earlier, in addition to the polyurethane resin (Al), color pigment (l3) and spherical silica
particles (C). Furthermore, in a case where the film forming resin (polyurethane resin
(Al) which is an essential component, and polyester resin (A2) and acrylic resin (M)
which are arbitrary components) of the color coating (a) is cured, the color cornpdsition
includes the above-described curing agent @).
[0079]
The color composition is not limited to a specified method, and may be oqtained
by an arbitrary method. If a preferable aqueous color composition is described as an
example, a method of adding constituent components of color coating (a) in water which
is a dispersion medium, stirring using a disperser, and dissolving or dispersing may be
5 exemplified. In order to improve the solubility or dispersibility of the respective
constituent components, known hydrophilic solvents or the like, for example, alco~ols,
I
such as ethanol, isopropyl alcohol, t-butyl alcohol and propylene glycol; cellosolv$s, ~
such as ethylene glycol monobutyl ether, or ethylene glycol monoethyl ether; esters, such
as ethyl acetate, or butyl acetate, ketones, such as acetone, methyl ethyl ketone and .
10 methyl isobutyl ketone may be added as needed.
The coating method of the color composition is not particularly limited, and a
known arbitrary method may be used. For example, it is possible to use roll coating,
curtain coating, spray coating, bar coating, dipping, electrostatic coating or the like.
15 [008 11
Heat-drying forming the color coating (a) from the color composition is not
particularly limited and may be performed using an arbitrary method. For example,
1 heating a metal plate in advance before coating the color composition, heating the metal
1 plate after coating, or drying by combining these may be performed. The heating
~ 20 method is also not particularly limited, and hot air, induction heating, near-infrared rays,
direct heating or the like may be used individually or combined, and the color
composition may be dried and baked by the heating method. The drying and baking
temperature is preferably a peak metal temperature of 150°C to 250°C, is more
preferably 160°C to 230°C, and is most preferably 180°C to 220°C. If the peak metal
I
C 42
temperature is less than 150°C, the baking and curing is insufficient, and the humi ity
resistance, corrosion resistance, scratch resistance, and chemical resistance of the f oating
film may be lowered; if exceeding 250°C, the baking and curing is excessive, and the
corrosion resistance and workability may be lowered. The drying and baking t i w
(heating time) is preferably 1 to 60 seconds, and is more preferably 3 to 20 seconds. If
the drying and balung time is less than one second, the baking and curing is insufficient,
and the humidity resistance, corrosion resistance, scratch resistance, and chemical
resistance of the coating film may be lowered; if the drying and baking time exceeds 60
seconds, productivity may be lowered.
[0082]
The chromate-free color coated metal plate according to the embodiment, may
be provided with a subbing layer (P) on a lower layer of the color coating (a). The
subbing layer (P) is not particularly limited, and, a layer including at least one type
selected fi-om, for example, a silane coupling agent, organic resin, or polyphenol
compound may be used. By providing this layer as a lower layer of the color coating, it
is possible to increase the adhesiveness of the metal plate to the color coating (a), and to
increase the corrosion resistance of the coating film. By providing a subbing layer (P)
including all of the silane coupling agent, organic resin, and polyphenol compound, it is
possible to increase the adhesiveness of the metal plate to the color coating (a) notably,
and to increase the corrosion resistance of the coating film notably.
[0083]
The silane coupling agent included in the subbing layer (P) is not particuliarly
limited, and examples include vinyltrimethoxysilane, vinyltriethoxysilane, y-aminopropyl
trimethoxysilane, y-aminopropyl triethoxysilane, N-[2-(vinylbenzyl-amino) ethyl]-3
aminopropyltrimethoxysilane, y-methacryloxypropyl methyl dimethoxy silane, I
y-methacryloxypropyl trimethoxysilane, y-methacryloxypropyl methyl diethoxysilme,
y-methacryloxypropyl triethoxysilane, y-glycidoxypropyl triethoxysilane,
y-glycidoxypropyl methyldiethoxysilane, y-glycidoxypropyltrimethoxysilane, 2-(314
5 epoxycyclohexyl) ethyltrimethoxysilane, ~ - ~ - ( h i n o e t h ~ l )
y-aminopropyltrimethoxysilane, N-P-(aminoethy1)-y-aminopropyltriethoxysilane,
N-P-(aminoethy1)-y-arninopropyl methyl dimethoxy silane, i
N-phenyl-y-aminopropyltrimethoxysilane, y-mercaptopropyltrimethoxysilane, or tte like,
sold by companies such as Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Co., Ltd.,
10 Chisso Corporation, and Momentive Performance Materials Japan. The silane caupling
agent may be used singly, or two or more may be used together.
[0084]
The organic resin included in the subbing layer (P) is not particularly limited,
and known organic resins, such as a polyester resin, polyurethane resin, epoxy resin,
15 phenol resin, acrylic resin, polyolefin resin or the like may be used. In order to improve
the adhesiveness between the color coating (a) and the metal plate, using at least one
type of polyester resin, polyurethane resin, epoxy resin, and phenol resin is preferable.
In a case where the color coating (a) includes a polyester resin, in signifying increasing
the compatibility and increasing the adhesiveness thereof, the subbing layer (P),
20 particularly preferably contains a polyester resin.
[0085]
As the phenol compound included in the subbing layer (P), a compound having
two or more phenolic hydroxyl groups bonded to a benzene ring, or a condensation
product thereof is used. As the compound having two or more phenolic hydroxyl
groups bonded to a benzene ring, examples include, for example, gallic acid, pyro$allol,
or catechol. The condensation product of the compound having two or more phe4olic
hydroxyl groups bonded to a benzene ring is not particularly limited, and examples
include, for example, phenol compounds widely distributed in the plant kingdom
5 ordinarily called tannic acid.
[0086]
Tannic acid is a general name for aromatic compounds with a complicated
structure having plural phenolic hydroxyl groups widely distributed in the plant
kingdoms. The tannic acid used in the subbing layer (P) may be a hydrolysable t m i c
10 acid or may be a condensed-type tannic acid. The tannic acid is not particularly limited,
and examples include, for example, harnameli tannin, persimmon tannin, tea tannin,
sumac tannin, gallnut tannin, myrobarans tannin, divi-divi pod tannin, algarovilla tannin,
valonia tannin, or catechin tannin. Commercially available tannic acid, for example,
"Tannic Acid Extract A", "B Tannic Acid", "N Tannic Acid", "Industrial Tannic Acid",
15 "Purified Tannic Acid", "High Tannic Acid", "F Tannic Acid", "Local Tannic Acid" (all
made by Dainippon Pharmaceutical), "Tannic Acid AL" (made by Fuji Chemical
Industry) or the like may be used.
[0087]
The polyphenol compound may use one type or may use two or more types
20 together.
[008 S]
The content ratio of the component (at least one type selected from the silane
coupling agent, organic resin, and polyphenol compound) included in the subbing layer
(p) is not particularly limited; however, 10 parts by mass or more being contained in 100
25 parts by mass of the subbing layer is preferable. In a case of less than 10 parts by mass,
the effect of improving the adhesiveness or corrosion resistance may not be obtain&d.
The deposition amount of the subbing layer (P) is not particularly limited;^
however, being in a range of 10 to 1000 mg/m2 is preferable. If less than 10 mg/m2,
5 sufficient effect of the subbing layer (P) may not be obtained; if exceeding 1000 mg/m2,
the subbing layer (P) easily undergoes cohesive failure and the adhesiveness may be
lowered. From a stable effect and economy, a more preferable deposition amound range
[0090]
10 The formation method of the subbing layer (P) is not particularly limited, pnd is
ordinarily formed by coating, heat-drying a coating agent for forming the subbing layer
(p) on at least one surface of a metal plate. Since it is superior in industrial productivity,
the coating agent being an aqueous coating agent in which the medium is water is
preferable. The coating agent is not limited a specified method and may be obtained by
15 an arbitrary method. For example, a method of adding constituent components of the
subbing layer (P) to water which is a medium, stirring using a disperser, and dissolving
or dispersing may be exemplified. In order to improve the solubility or dispersibility of
the respective constituent components, one or two or more types of known hydrophilic
solvents or the like fiom among, for example, alcohols, such as ethanol, isopropyl
20 alcohol, t-butyl alcohol and propylene glycol; cellosolves, such as ethylene glycol
monobutyl ether, or ethylene glycol monoethyl ether; esters, such as ethyl acetate, or
butyl acetate, ketones, such as acetone, methyl ethyl ketone and methyl isobutyl ketone
may be added as needed. The coating method of the coating agent is not particularly
limited, and a known roll coat, spray coating, bar coating, dipping, electrostatic coating
t 46 I
or the like may be appropriately used. The method of heat-drying is not particul
limited, and heating a metal plate in advance before coating the coating agent, heathg the
metal plate after coating, or drying by combining these may be performed. The heating
method is not particularly limited, and hot air, induction heating, near-infrared rays,
5 direct heating or the like may be used individually or combined. The drying and baking
I temperature is preferably a peak metal temperature of 60°C to 1 50°C, and is more
preferably 70°C to 130°C. If the peak metal temperature is less than 60°C, drying, is
insufficient, and the adhesiveness between the coating film and the metal plate, or the
corrosion resistance of the color coating may be lowered; if exceeding 1 50°C, the
10 adhesiveness between the coating film and the metal plate may be lowered.
COO9 11
The metal plate applicable to the invention is not particularly limited, and
examples include, for example, iron, an iron-based alloy, aluminum, aluminum-based
alloy, copper, or copper-based alloy. In addition to these metal plates a plated metal
15 plate which is plated may be used. Among these, the most appropriate to those applied
to the invention are a zinc-based plated steel plate and an aluminum-based plated steel
plate.
The zinc-based plated metal plate includes a zinc plated steel plate, zinc-nickel
plated steel plate, zinc-iron plated steel plate, zinc-chromium plated steel plate,
zinc-aluminum plated steel plate, zinc-titanium plated steel plate, zinc-magnesium plated
steel plate, zinc-manganese plated steel plate, zinc-aluminum-magnesium plated steel
plate, zinc-aluminum-magnesium-silicon plated steel plate, or other zinc-based plated
steel plate; and further, the plating layers thereof may contain small amounts of different
types of metal atoms or impurities, such as cobalt, molybdenum, tungsten, nickel,
* 47
titanium, chromium, aluminum, manganese, iron, magnesium, lead,'bismuth, anti m , ony,
tin, copper, cadmium, arsenic or may have inorganic materials, such as silica, aluqina,
titania or the like dispersed.
[0093]
5 Examples of the aluminum-based plated steel plate include an aluminum plated
steel plate or a steel plate plated with an alloy formed fiom aluminum and at least one of
silicon, zinc, and magnesium, for example, an aluminum-silicon plated steel plate,
aluminum-zinc plated steel plate, aluminum-silicon-magnesium plated steel plate, or the
like.
Furthermore, it is possible to use a multi-layer plated steel plate in which the
above platings and other types of plating, for example, iron plating, iron-phosphorus
plating, nickel plating, cobalt plating, or the like, are combined.
15 The plating method is not particularly limited, and any method, such as a known
electroplating method, hot-dip coating process, deposition plating method, dispersion
plating method, vacuum plating method or the like may be used.
Examples
The invention will be further described using Examples. However, the
invention is not limited to the Examples below.
[0097]
(I) Metal Plate
2 5 The types of metal plate used are shown in Table 1. For the base material of
the metal plate subjected to plating, a soft metal plate with a plate thickness of 0.5 /mm
I
was used. For the SUS plate, a ferrite-based stainless steel plate (steel components: C:
0.008 mass%, Si: 0.07 mass%, Mn: 0.15 mass%, P: 0.011 mass%, S: 0.009 mass%,Al:
0.067 mass%, Cr: 17.3 mass%, Mo: 1.51 mass%, N: 0.0051 mass%, Ti: 0.22 mass%, the
5 balance being Fe and inevitable impurities) was used. The surface of the metal plate
was treated to alkali degreasing, washed, dried and.used.
[Table 11
1 No. 1 Metal Plate (plate thickness 0.5 mm, both sides plated) I
M1
M2
electrogalvanized steel plate (plating deposition amount 20 g/m2)
hot dip galvanized steel plate (plating deposition amount 60 g/m2)
M3
M4
I M8 I SUS plate (ferrite-based stainless steel plate) I
galvannealed steel plate (Fe: lO%,plating deposition amount 45 g/m2)
Electro Zn-10% Ni alloy plated steel plate (plating deposition amout 20
dm2)
M5
M6
M7
[0099]
(2) Subbing layer
Coating agents for forming the subbing layer were prepared by, blinding an
organic resin (Table 2), a silane coupling agent (Table 3), a polyphenol compound (Table
" I
hot dip Zn-11% AI-3% Mg-0.2% Si plated steel plate (plating deposition
amount 60 g/m2)
hot dip Zn-55% Al-1.6% Si plated steel plate (plating deposition amount
75 g/m2)
hot dip Al-9% Si plated steel plate (plating deposition amount 40 g/m2)
4) in the blending amounts (mass%) showing in Table 5, and stirred using a coating
material disperser. A coating agent was coated using a roll coater so as to have a
15 deposition amount of 100 mg/m2 on the surfaces of the metal plates prepared in (I), and a
subbing layer was formed as necessary by drying in conditions of a peak metal
temperature of 70°C.
[O 1001
[Table 21
No.
-1
Organic resin
aqueous polyester resin (manufactured by Toyobo Co., Ltd., Vylonal
U +
-*
MD-1200)
aqueous epoxy resin (manufactured by Adeka Corporation, Adeka Resin
aL
- ?
[Table 31
~ ~ 0 4 3 6 F1S2)-
aqueous phenol resin (manufactured by Sumitomo Bakelite Co., ~ t d . ,
a3
a4
P R - ~ ~ 112) 6
aqueous acrylic resin (manufactured by NSC Japan, Nevinol KD-5)
[Table 41
No.
c 1
c2
Silane coupling agent
3-glycidoxypropyl trirnethoxysilane
3-aminopropyl triethoxysilane
[Table 51
No.
d 1
1 30 1 25 1 25 I * Silica I 20
* Silica: Snowtex N (manufactured by Nissan Chemical)
Polyphenol compound
tannic acid (Fuji Chemical Industry Co., Ltd., Tannic acid AL)
[0 1031
(3) Polyurethane Resin
(Preparation of Polyester Polyol)

While introducing nitrogen gas to a reaction container including a thermometer,
a nitrogen gas introduction pipe and stirrer, 443 parts by weight of terephthalic acid, 443
parts by weight of isophthalic acid, 420 parts by weight of adipic acid, 196 parts by
weight of ethylene glycol, 306 parts by weight of 1,4-butanediol, 328 parts by weight of
neopentyl glycol and 0.5 parts by weight of dibutyl tin oxide were prepared and stirred.
10 Next, while introducing nitrogen gas, the temperature was raised to 230°C, and a
polycondensation reaction was performed at the same temperature for 15 hours until the
acid value was one or lower, and a polyester polyol PO1 was obtained.
[0 1051

15 With the raw material compositions shown in Table 6, the polyester polyols PO2
to PO7 were obtained using the same procedure as Manufacturing Example Pol. In
any of the preparations, the dibutyl tin oxide was 0.5 parts by weight.
[0 1061
In Table 6, the number average molecular weights (polystyrene converted values
20 using GPC measurement) of the polyester polyols PO1 to PO7 and the content ratio
(mass%) of the aromatic ring structure in the polyester polyols Pol to PO7 solids are also
shown. Moreover, the content ratio of the aromatic ring structure in the solids of these
polyester polyols PO1 to PO7 are calculated by substituting the denominator in Formula
[I] {polyurethane resin (Al) solids mass (g)) with {polyester polyol solids mass (g)).
[Table 61
[0108]
(Preparation of Water Dispersion of Polyurethane Resin)
5
1000 parts by mass of polyester polyol Pol, 40 parts by mass of 2,2'-dimethylol
propionic acid, were added to 900 parts by mass of methyl ethyl ketone, and dissolved by
heating to 80°C. Thereafter, 250 parts by mass of isophorone diisocyanate were added,
10 reacted for 2 hours by heating to llO°C, and neutralized by adding 60 parts by mass of
(Numerical
Value of Raw
Material is
Mass%)
Terephthalic
acid
Isophthalic acid
Adipic acid
Ethylene
Glycol
1,4-propanediol
Neopentyl
Glycol
Content ratio of
aromatic ring
structure in
Polyester
polyol solids
(mass%)
Numerical
average
molecular
weight
triethylamine. Next, the solution is added dropwise under strong stirring to an ac&eous
solution in which 10 parts by mass of ethylenediarnine and 4000 parts by mass of
deionized water are mixed, and finished by chain elongation and aqueously dispersed.
PO1
443
443
420
196
306
328
23.0
1500
Manufactured
PO4
25 1
953
299
501
7.0
1500
Polyester
PO2
675
675
299
501
34.6
1500
polyol
PO3
28 1
281
740
124
538
207
14.4
1500
PO5
1250
906
0
1500
Example
PO6
693
693
278
466
36.1
5000
PO7
854
470
278
466
23.0
5000
52
?!ubsequently, the concentration was adjusted by adding deionized water after methyl
ethyl ketone was removed with the aqueous dispersion solution at 50°C and a reduced
pressure of 150 rnmHg, and an aqueous dispersion PU1 of polyurethane resin with a
resin solids concentration of 30 mass% was obtained.
5 [0 1091

With the raw material compositions shown in Tables 7 and 8, the aqueous
dispersions PU2 to PU19 with 30 mass% of resin solids of polyurethane resin were
10 obtained using the same procedure as Manufacturing Example PU1.
[OllO]
[Table 71
[Olll]
[Table 81
(Numerical value of raw material is parts by mass)
Polyester polyol PO 1
Polyester polyol PO2
Polyester polyol PO3
Polyester polyol PO4
Polyester polyol PO5
Polyester polyol PO6
Polyester polyol PO7
2,2'-dimethylol propionic acid
neopentyl glycol
tolylene diisocyanate
diphenyl methane diisocyanate
isophorone diisocyanate
hexamethylene diisocyanate
ethylenediamine
Resin solids (mass%)
Content ratio of polyester polyol derived aromatic ring
structure in polyurethane resin solids (mass%)
Content ratio of isocyanate derived aromatic ring structure in
polyurethane resin solids (massY0)
Manufacturing
PU15
1070
80
10
245
30
17.5
7.8
PUlO
260
80
320
727
20
30
6.4
23.2
Polyurethane
PU12
1000
80
10
295
20
30
0
9.4
Pull
890
8 0
10
405
20
30
14.6
18.0
Example
PU16
1000
8 0
280
30
16.9
0
resin
PU13
930
8 0
10
366
20
30
15.2
0
PU17
980
8 0
10
206
110
20
30
16.0
6.6
PU14
1010
8 0
10
286
20
30
16.5
0
PU18
1004
8 0
10
221
7 1
20
30
16.4
7.0
The content ratio of the aromatic ring structure in the polyurethane resin solids
was calculated on the basis of Formula [I] for the obtained aqueous dispersions PU1 to
PU 19 of polyurethane resin.
[0113].
(4) Polyester Resin

199 parts of terephthalic acid, 232 parts of isophthalic acid, 199 parts of adipic
acid, 33 parts of 5-sodium sulfo isophthalic acid, 250 parts of ethylene glycol, 125 parts
of 2,2 dimethyl-1,3-propanediol, 187 parts of 1,s-pentanediol, 62 parts of bisphenol A
ethylene oxide adduct and 0.41 parts of tetrabutyl titanate were added to a reaction
container equipped with a stirrer, condenser and thermometer, and an esterification
* 3 1 reaction was performed over 4 hours fiom 160°C to 230°C. Next, within the system
was gradually depressurized, reduced in pressure to 5 rnmHg over 20 minutes, and
further, a polycondensation reaction was performed in a true vacuum of 0.3 mmHg or
less at 260°C for 40 minutes. After 100 parts of the obtained copolymer polyester resin,
5 20 parts of butyl cellosolve, and 42 parts of methyl ethyl ketone were introduced,
dissolution was performed by stirring for 2 hours at 80°C, a further 213 g of ion
exchange water was introduced and aqueously dispersed. hereafter, the solvent was
removed while heating, the dispersion was filtered using a 200 mesh nylon mesh, and
aqueous dispersion PE3 with a 30% solids concentration of polyester resin was obtained.
10 [0116]
(3) Color Coating
The color composition for forming the coating film was prepared by blending an
aqueous dispersion of organic resin (the above Manufacturing Examples PU1 to PU19,
PE1 to PE3, and Tables 8 and 9), curing agent (D) (Table lo), color pigment (B) (Table
15 1 l), silica particles (C) (Table 12), lubricant (E) (Table 13) in the blending amounts
shown in Tables 14 to 20, and stirring using a coating material disperser. In the
manufacturing examples, simply "parts" indicates "parts by mass", and simply "%"
indicates "mass%". On the upper layer of the subbing layer (metal plate in a case of no
subbing layer) formed in (2), a coating layer is formed by coating the color composition
20 using a roll coater so as to be a predetermined thickness, and heat-drying so as to have a
predetermined peak metal temperature.
No.
[0117]
[Table 91
Or-ga nic resin
Polyurethane resin (Manufacturing Example PUl, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU2, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU3, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU4, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU5, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU6, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU7, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU8, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU9, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PUlO, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example P u l l , containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU12, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU13, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU14, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufacturing Example PU 15, not containing urea group,
containing urethane group, carboxyl group)
Polyurethane resin (Manufacturing Example PU16, not containing urea group,
containing urethane group, carboxyl group)
Polyurethane resin (Manufacturing Example PU17, containing urea group, urethane
group, carboxyl group)
-
Polyurethane resin (Manufacturing Example PU18, containing urea group, urethane
group, carboxyl group)
Polyurethane resin (Manufactured by Mtsui Chemicals, Takelac WS-602 1, containing
urea group, urethane group, carboxyl group)
* polyether polyol-based
Polyurethane resin (Manufactured by Dai-Ichi Kogyo Seiyaku Co., Ltd., Superflex
620, containing urea group and urethane group, not containing carboxyl group)
* cationic, polyester polyol-based
Polyester resin (Manufacturing Example PEl, containing sodium sulfonate group)
Polyester resin (Manufacturing Example PE2, containing carboxyl group)
Polyester resin (Manufacturing Example PE3, containing bisphenol group, sodium
sulfonate group)
Acrylic resin (manufactured by Johnson Polymer, Joncryl J-6 1)
Polyolefin resin (manufactured by Toho Chemical Industry Co., Ltd., HYTEC S-3 12 1)
Polyurethane resin (Manufacturing Example PU19, containing urea group, urethane
group, carboxyl group)
[0118]
[Table 101
I No. Curing Agent (D) I
I Dl I Melamine resin (manufactured by Nihon Cytec Industries, Cyrnel303) 1
[0119]
[Table 1 I]
D2
D3
Melamine resin (manufactured by Nihon Cytec Industries, Cyme1 325)
Isocyanate compound (manufactured by Mitsui Chemicals, Takenate
WD-725)
[Table 121
No.
B1
B2
B3
Color Pigment (B)
Carbon black (manufactured by Mitsubishi Chemical Corporation,
MCF#980, particle diameter 16 nm)
Carbon black (manufactured by Mitsubishi Chemical Corporation, MA1 00,
particle diameter 24 nm)
Titanium oxide (manufactured by Ishihara Sangyo ~aishaL,t d., R-780,
particle diameter 240 nm)
No.
r( 'l
Silica particles (C)
Colloidal silica (manufactured by Nissan Chemical Industries, Ltd.,
Ll
nq
Snowtex N, pa&cle diameter 15-nm)
Colloidal silica (manufactured by Nissan Chemical Industries, Ltd.,
LL
A,l
L4 I Snowtex YL, particle diameter 65 nrn)
[0121]
Snowtex NXS, particle diameter 5 nm)
Colloidal silica (manufactured by Nissan Chemical Industries, Ltd.,
L3
/ , A
[Table 131
Snowtex XL, particle diameter 50 nm)
Colloidal silica (manufactured by Nissan Chemical Industries, Ltd.,
No.
El
E2
E3
E4
Lubricant (E)
Polyethylene (manufactured by Mitsui Chemicals, Chemipearl W950,
particle diameter 0.6 pm)
Polytetrafluoroethylene (manufactured by Asahi Glass, AD9 1 1, particle
diameter 0.3 pm)
Polyethylene (manufactured by Mitsui Chemicals, Chemipearl WF640,
particle diameter 1.0 pm)
Polyethylene (manufactured by Mitsui Chemicals, Chemipearl W500,
particle diameter 2.5 pm)
(4) Color Coated Metal Plate
The coating composition of the color coated metal plate on which the color
coating (a) is formed as described in (3) and the film thickness of the color coating, and
5 the peak metal temperature are shown in Tables 14 to 20.
[0123]
[Table 141
[0 1241
[Table 151
[Table 161
* 1 Proportion included in organic resin, *2 Proportion with respect to 100 mass% of organic resin, *3 Proportion included in color coating
[0126]
[Table 171
Example 74
Example75
Example 76
Example77
Example 78
Example 79
Example 80
* 1 Proportion included in organic resin, *2 Proportion with respect to 100 mass% of organic resin, *3 Proportion included in color coating
M1
M1
M1
M1
M1
M2
M2
$5
p6
p7
pS
!39
P4
p4
A1
A1
A1
A1
A1
A1
A1
74
74
74
74
74
100
100
A21
A21
A21
A21
A21
24
24
24
24
24
A24
A24
A24
A24
A24
2
2
2
2
2
Dl
Dl
Dl
Dl
Dl
Dl
15
15
15
15
15
15
B2
B2
B2
B2
B2
B2
B2
8
8
8
8
8
8
8
C1
C 1
C1
C1
C1
C1
C1
15
15
15
15
15
15
15
El
El
El
El
El
El
El
3
3
3
3
3
3
3
4
4
4
4
4
4
4
200
200
200
200
200
200
200

[0128]
[Table 191
[Table 201
No.
Comparative
Example 11
Comparative
Example 12
Comparative
Example 13
Comparative
Example 14
Comparative
Example 15
Comparative
Example 16
Comparative
Example 17
Comparative
Example 18
Comparative
Example 19
Comparative
Example 20
Comparative
Example 2 1
Comparative
Example 22
Comparative
Example 23
Comparative
Example 24
* 1 Proportion
Metal
plate
M1
M1
M1
M1
M1
M1
M1
included
peak
Metal
Temperat
ure ("C)
200
200
200
200
200
200
200
200
200
200
200
200
200
200
Subbing
Layer(P)
P4
P4
P4
P4
P4
P4
P4
P4
P4
P4
P4
P4
P4
P4
in organic
~ i l ~
thick
ness
( ~ 4
4
4
4
4
4
4
4
4
4
4
4
4
1.5
12
Silica particles Lubricant
Type
El
E 1
El
E 1
El
El
El
El
El
El
El
El
El
E 1
coating
Type
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1
included
(E)
*3
Amoun
(
3
3
3
3
3
3
3
3
3
3
3
3
3
3
(a)
(a)
Color pigment
(C)
*3
Amoun
t (%)
15
15
15
15
15
15
15
15
15
15
15
15
in color
Type
B2
B2
B2
B2
B2
B2
B2
B2
B2
B2
B2
B2
B2
B2
*3
Color coating
(B)
*3
Amoun
t (%)
8
8
8
8
8
8
8
8
8
8
8
8
8
8
Proportion
Curing
Type
D 1
D 1
D 1
of organic
Other
resins
A25
A25
A25
to 100
-
z:r
A12
A13
A14
A15
A16
A17
A18
A19
A20
A1
A1
A1
A1
resin,
agent @)
*2
Amoun
t (?h)
15
15
15
resin,
* 1
Amount
(%) .
100
2
2
mass%
Organic
Polyest
er resin
A21
A21
with
*I
$:un
100
100
100
100
100
100
100
100
100
100
100
74
74
*2 Proportion
resin
* 1
Amo
unt
(%I
24
24
respect
I (5) Evaluation Test
The color coated metal plates (test plates) prepared as described in (3) were
evaluated for design characteristics, humidity resistance, corrosion resistance,
5 workability (design characteristics, and worked adhesiveness of the worked parts),
I -
scratch resistance, and chemical resistance of the flat plate parts, using the evaluation
methods and evaluation standards shown below. The evaluation results thereof are
shown in Tables 21 to 27.
[013 11
10 (Design Characteristics of Flat Plate Parts)
1 The appearance of a test plate was evaluated using the evaluation standard
below.
5: Color and surface luster were both uniform. Base also not visible at all
therethrough.
15 4: Color uniform; however, surface luster slightly non-uniform (level able to
be somehow confirmed by focusing the eyes carefully). Base not visible at all
therethrough.
3 : Color and surface luster both slightly uneven (level able to be somehow
confirmed by focusing the eyes carefully). Base not visible at all therethrough.
20 2: Color and surface luster both uneven (level able to be easily confirmed
visually). Base not visible at all therethrough.
1 : Color and surface luster both uneven (level able to be easily confirmed
visually). Base somewhat visible therethrough.
[0132]
25 (Humidity Resistance)
temperature 40°C and a humidity of 90% was evaluated using the evaluation standard
below.
5: No changes in appearance observed at all.
5 4: Surface luster extremely slightly lowered (level somehow ascertained when
~ lined up beside test plate before testing).
~ 3: Surface luster slightly lowered (level easily ascertained when lined up
beside test plate before testing).
2: surface luster lowered (level somehow ascertained by viewing only test
10 plate).
1 : Surface luster remarkably lowered (level easily ascertained by viewing only
test plate).
[0133]
(Corrosion Resistance)
15 After the surface on and close to edges of a test plate was sealed by tape, a salt
spray test (SST) conforming to JIS Z 2371 was performed for 168 hours, the state of
occurrence of rust was observed and evaluated using the evaluation standard below.
5: No occurrence of rust.
4: Area in which rust occurs less than 1%.
20 3: Area in which rust occurs 1% or higher and less than 2.5%.
2: Area in which rust occurs 2.5% or higher and less than 5%.
1: Area in which rust is generated is *BR>T or higher.
[0134]
(Workability (Design Characteristics of Worked Parts))
2 5 A test plate was subjected a 180" bending work, and the appearance of the outer
side of the bent portion was evaluated using the evaluation standard below. The
bending work was executed in a 20°C atmosphere with a 0.5 mm thick spacer interposed
therebetween (ordinarily referred to as 1T bending)
5: No craclung or other defects in coating film, uniform color appearance.
I 5 No color loss observed.
4: Since extremely slight cracking observed in coating film, slight color loss
observed; however, nearly uniform color appearance (level somehow ascertained when
lined up beside test plate before testing).
3: Since slight craclung observed in coating film, slight color loss observed;
10 however, nearly uniform color appearance (level easily ascertained when lined up beside
test plate before testing).
2: Cracking observed in coating film, and color loss observed (level somehow
ascertained by viewing only test plate).
1 : Cracking observed in coating film and color loss is remarkable (level easily
15 ascertained by viewing only test plate).
[0135]
(Workability (Worked Adhesiveness of Worled Parts))
After the test plate was subjected to the 180" bending work, a tape peeling test
(tape peeling method conformed to JIS K 5600-5-6) was performed on the outer side of
20 the bent worked portion. The appearance of the tape peeling portion was evaluated
using the evaluation standard below. Moreover, the bending work was executed in a
20°C atmosphere with a 0.5 mrn thick spacer interposed therebetween (ordinarily
referred to as 1T bending).
5: Peeling not observed in the coating film.
4: Peeling observed in coating film at extremely small portion (extent
C 7 1
somehow ascertained by observing using a loupe).
3: Peeling observed in one portion of coating film (extent ascertained by
observing using a loupe).
2: Peeling observed in part of coating film (extent easily ascertained visually).
5 1 : Peeling observe in almost all of the coating film (extent easily ascertained
visually).
[0136]
(Scratch Resistance)
Five lines were scratched on a test plate using a pencil lead at 45O, and the plate
10 was evaluated using the pencil hardness in which two or more times scratches were not
formed. The pencils were Uni pencils manufactured by Mitsubishi Pencil Co., Ltd,
testing was performed at 20°C under load conditions of 4.903 N (500 gf), and evaluation
was performed using the evaluation standard below. Other test conditions conformed to
JIS K 5600-5-4.
15 5: Pencil hardness is 3H or higher.
4: Pencil hardness is 2H.
3: Pencil hardness is H.
2: Pencil hardness is F.
1 : Pencil hardness is HI3 or lower.
20 [0137]
(Chemical Resistance)
After installation of a test plate in a rubbing tester, the coating condition was
evaluated using the evaluation standard below after absorbent cotton impregnated with
ethanol was rubbed and reciprocated 20 times and 50 times under a load of 49.03 kPa
25 (0.5 kgf/cm2).
72
5: No traces at all on rubbing surface.
4: Extremely slight traces on rubbing surface (level at which rubbing traces are
able to be determined by focusing the eyes carefully).
3 : Slight traces on rubbing surface (level at which rubbing traces are easily
5 able to be determined by focusing the eyes carefully).
2: Clear traces on the rubbing surface (level at which rubbing traces are able to
be instantly determined visually).
1 : Coating dissolves on rubbing surface, base is exposed.
[0138]
[Table 2 11
Scratch Remarks
resistance
5
5
No.
Example 1
Example 2
Workability
parts
design
characteristics
4
4
Worked parts
design
characteristics
4
4
Chemical resistance
Worked parts
adhesiveness
5
5
20 reciprocations
5
5
Humidity
resistance
5
5
50 reciprocations
4
4
Corrosion
resistance
5
5
[0139]
[Table 221
[0140]
[Table 231
Scratch Remarks
resistance
3
4
No. *
Example 41
Example 42
Corrosion
resistance
4
5
design
characteristics
5
4
Chemical resistance
Humidity
resistance
5
5
Workability
20 reciprocations
5
5
Worked parts
design
characteristics
5
4
50 reciprocations
3
4
Worked parts
adhesiveness
5
5
[0141]
[Table 241
[0 1421
[Table 251
characteristics
[0143]
[Table 261
[0 1441
[Table 271
Remarks
gelling
bubbling
occurs
Scratch
resistance
4
4
4
4
4
5
5
4
2
3
2
2
2
5
Chemical
20 reciprocations
1
1
1
1
1
2
1
1
1
1
4
2
5
5
No.
Comparative
Example 11
Comparative
Example 12
Comparative
Example 13
Comparative
Example 14
Comparative
Example 15
Comparative
Example 16
Comparative
Example 17
Comparative
Example 18
Comparative
Example 19
Comparative
Example 20
Comparative
Example 21
Comparative
Example 22
Comparative
Example 23
Comparative
Example 24
resistance
50 reciprocations
1
1
1
1
1
1
1
1
1
1
3
1
5
5
Workability
Worked parts design
characteristics
5
5
5
5
5
4
4
5
1
2
4
4
1
2
Flat plate parts
design characteristics
4
4
4
4
4
4
4
4
1
4
4
4
2
4
Worked parts
adhesiveness
5
5
5
5
5
5
5
5
1
1
2
2
5
5
Humidity
resistance
5
5
5
5
5
5
5
5
3
5
5
4
5
5
Corrosion
resistance
2
1
1
1
1
3
2
1
1
1
1
1
2
3
8 0
[0145]
The examples of the invention showed superior design qualities in the flat
portions, humidity resistance, corrosion resistance, workability, scratch resistance, and
chemical resistance of 3 points or higher in any of the evaluation tests. On the other
5 hand, in the organic resin which is a film forming component in the color coating,
Comparative Examples 1, 8, 11, 18 using a polyurethane resin (A12, A19 shown in Table
9) not containing polyester polyol derived structural units having an aromatic ring
structure; Comparative Examples 2,3, 6,7, 12, 13, 16, 17 using a polyurethane resin
(A13, A14, A17, A18 in Table 9) not containing an aromatic ring structure in all of the
10 isocyanate component (b) derived structural units; Comparative Examples 4, 14 using a
polyurethane resin (A1 5 in Table 9) not containing a urea group; Comparative Examples
5, 15 using a polyurethane resin (A16 in Table 9) not containing an aromatic ring in
isocyanate component (b) derived structural units, and not containing a urea group,
which are comparative examples outside the scope of the invention, were degraded in
15 one or both of corrosion resistance and chemical resistance. Comparative Examples 9,
10, 19 and 20 using the polyurethane resin (A20 shown in Table 9) not containing a
carboxyl group and containing a cationic functional group and the polyolefin resin (A25
shown in Table 9) were degraded in one or more of design characteristics in the flat
portions, corrosion resistance, workability, scratch resistance and chemical resistance.
20 Moreover, when storage stability of the aqueous color composition used in the Examples
of the invention and the Comparative Examples when left for one day at 40°C, the
aqueous color composition used in Comparative Examples 9 and 19 had gelled. In
other words, the storage stability of the color compositions using polyurethane resin A20
not containing a carboxyl group and containing a cationic fbnctional group was degraded
25 compared to other color compositions, and was determined to not be a usable level. In
addition, the corrosion resistance, worked parts adhesiveness, and scratch resistance were
degraded in Comparative Examples 21 and 22 not containing silica particle (C) (solvent
resistance of Comparative Example 22 was also degraded). The flat part design
characteristics, corrosion resistance, worked parts design characteristics and scratch
5 resistance of the Comparative Example 23 with a color coating film thickness of 1.5 p
are degraded; and the worked parts design characteristics of Comparative Example 24
with a color coating film thickness of 12 pm are degraded, along with the occurrence of
coating film defects known as bubbling.
Moreover, if the Examples 1 to 109 having both a polyester polyol component
10 (a) having an aromatic ring structure and isocyanate component (b) having an aromatic
ring structure and Comparative Examples 1 to 20 not having either of a polyester polyol
component (a) having an aromatic ring structure and isocyanate component (b) having an
aromatic ring structure are compared, it is possible to confirm extremely superior
chemical resistance in Examples 1 to 109. From such a comparison, it can be
15 ascertained that extremely superior chemical resistance may be obtained by having both
of a polyester polyol component (a) having an aromatic ring structure and a isocyanate
component (b) having an aromatic ring structure.
Furthermore, among the Examples 1 to 109, it may be ascertained that
"Examples 6, 10, 18,22,31,35 in which the content ratio of aromatic ring structure
20 included in the isocyanate component (b) having an aromatic ring structure does not fall
within the numerical range of 5 to 20 mass% of polyurethane resin (Al)" and "Examples
5, 17,30, 107, 108, 109 in which the content ratio of aromatic ring structure included in
the polyester polyol component (a) having an aromatic ring structure does not fall within
the numerical range of 5 to 25 mass% of polyurethane resin (Al)" do not exhibit as
25 superior chemical resistance or workability as examples other than these Examples 5, 6,
-,
10, 17, 18,22,30,3 1,35, 107, 108 and 109. From this point, it may be ascertained that
by either or both of "the content ratio of aromatic ring structure included in the
isocyanate component (b) having an aromatic ring structure falling within the numerical
range of 5 to 20 mass% of polyurethane resin (Al)" and "the content ratio of aromatic
5 ring structure included in the polyester polyol component (a) having an aromatic ring
structure falling within the numerical range of 5 to 25 mass% of polyurethane resin (Al)",
it is possible to exhibit more superior chemical resistance and workability.
[0 1461
Above, preferred embodiments of the present invention have been described;
10 however, it is needless to say that the invention is not limited to the examples. It is clear
that a person skilled in the art may conceive of various changes or modifications within
the scope disclosed in the claims, and it is understood that these naturally fall in the
technical scope of the invention.
15 Industrial Applicability
[0147]
According to the present invention, it is possible to provide an inexpensive
chromate-fiee color coated metal plate having extremely superior design characteristics
(colorability and concealment of sites including worked portions), humidity resistance,
20 corrosion resistance, workability, scratch resistance, and chemical resistance, without
including hexavalent chromium with high environmental burden characteristics.

8 3
CLAIMS
1. A chromate-fiee color coated metal plate with superior chemical residtance
having, on at least one side of the metal plate, a color coating comprising:
5 a film forming component including a polyurethane resin containing a uraa
group, a urethane group and a carboxyl group;
a color pigment; and
spherical silica particles with an average particle diameter of 5 to 50 nrn,
wherein the polyurethane resin includes:
10 a polyester polyol component derived structural unit having an aromatic
ring structure; and
an isocyanate component derived structural unit having an aromatic
ring structure,
all of the isocyanate component derived struclral units contain aromatic rings,
15 and
the color coating film has a film thickness of 2 to 10 pm.
2. The chromate-fiee color coated metal plate with superior chemical
resistance according to claim 1, wherein the aromatic ring structure included in the
20 isocyanate component having an aromatic ring structure is contained in the polyurethane
resin at 5 to 20 mass%.
3. The chromate-fiee color coated metal plate with superior chemical 1
resistance according to claim 2, wherein the aromatic ring structure included in the
25 polyester polyol component having the aromatic ring structure is contained in the
* 84
polyurethane resin at 5 to 25 mass%.
4. The chromate-free color coated metal plate with superior chemical
resistance according to any one of claims 1 to 3, wherein the isocyanate component is
5 tolylene diisocyanate.
5. The chromate-flee color coated metal plate with superior chemical
resistance according to any one of claims 1 to 3, wherein the film forming component of
the color coating film further contains a polyester resin containing a sulfonate group.
10
6. The chromate-free color coated metal plate with superior chemical
resistance according to any one of claims 1 to 3, wherein the film forming component of
the color coating film is cured by a curing agent.
15 7. The chromate-free color coated metal plate with superior chemical
resistance according to any one of claims 1 to 3, wherein the color coating film further
includes a lubricant.
8. The chromate-free color coated metal plate with superior chemical
20 resistance according to any one of claims 1 to 3, having a subbing layer as the lower
layer of the color coating film.
9. A chromate-free color coated metal plate with superior chemical resi 8t ance
on which the color coating film according to any one of claims 1 to 3 is formed on at
25 least one surface of a metal plate using an aqueous medium by coating and heat-drying a
85
3 color composition including a coating film constituent component.
10. An aqueous color composition comprising:
a polyurethane resin containing a urea group, a urethane group and a carboxyl
a color pigment; and
spherical silica particles,
wherein the polyurethane resin includes:
a polyester polyol component derived structural unit having an aromatic
10 ring structure; and
an isocyanate component derived structural unit having an aromatic
ring structure, and wherein
all of the isocyanate component derived structural units contain aromatic rings.
15 11. The aqueous color composition according to claim 10, wherein the
aqueous color composition further contains a polyester resin containing a sulfonate
group-