JPH04255765A - Matte coating and method for coating the same - Google Patents

Abstract

PURPOSE:To obtain a matte coating capable of finishing films excellent in acid, water, yellowing and solvent resistance, curability, etc., without changing matte effects even by polishing and provide a method for coating the same. CONSTITUTION:A matte coating is obtained by blending (C) an amino resin and (D) glass powder having 5-50mum particle diameter and the surface treated with alumina and/or silica with two kinds of acrylic resins (A) and (B) containing specific amounts of carboxyl groups, hydroxyl groups and epoxy groups. A method for coating colored surfaces with the aforementioned coating as a clear coating is provided.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a matte paint that forms a coating film that is particularly excellent in acid resistance, matteness, and scratch resistance, and also has good hardenability, water resistance, yellowing resistance, and solvent resistance. Regarding the painting method.

0002

[Prior art and its problems] In automotive top coatings,
Acid rain (pH 2-5) caused by air pollutants such as sulfur oxides and nitrogen oxides, which has become a global problem in recent years.
There is a strong desire to develop paints that can form coatings that can withstand such conditions.

[0003] Conventionally, urethane paints using polyisocyanate compounds as crosslinking agents have shown excellent acid resistance, but because they are two-component, they are complicated to handle, and moreover, the polyisocyanate compounds are said to have strong toxicity. There are drawbacks. In addition, these drawbacks can be solved by using blocked polyisocyanate compounds, but the dissociation temperature is high and the coating film is insufficiently cured at the current line baking temperature (140-150°C), and the coating film is hardened by the blocking agent. There is a problem that it easily yellows due to heat.

[0004] Furthermore, a composition comprising a carboxyl group-containing resin and an epoxy group-containing resin has excellent acid resistance, but poor solvent resistance. Furthermore, carboxyl group-containing resin,
Compositions consisting of epoxy group-containing resins and melamine resins (JP-A-63-113087, JP-A-1-139)
No. 655) has the disadvantage that compatibility decreases when a large number of functional groups are introduced to improve acid resistance, solvent resistance, etc. In addition, carboxyl group in the same molecule,
A resin composition consisting of a resin containing an epoxy group and a hydroxyl group and a melamine resin (see Japanese Patent Publication No. 47-3734) is also known, but in order to improve the acid resistance of the coating film, the former resin is When a large number of functional groups are introduced, gelation tends to occur during the polymerization reaction, and this is also disadvantageous in terms of long-term storage stability.

On the other hand, top coatings on automobile exterior panels are generally finished in glossy coatings with excellent gloss, but in recent years,
As a new design, it may be finished with a matte coating. Up until now, silica powder has often been added to create a matte finish, but since the silica powder floats on the surface of the coating, when the coating is polished, the silica powder separates and leaves that area. However, it becomes shiny, which deteriorates the appearance, which is undesirable. Furthermore, it also has the defect of reduced scratch resistance, stain resistance, and weather resistance.

[0006]

[Means for Solving the Problems] The present inventors have conducted extensive research to solve these problems, and as a result, we have developed a new product that has excellent acid resistance, matteness, and scratch resistance, as well as hardenability and yellowing resistance. They have discovered a matte paint that forms a coating film with excellent solvent resistance and water resistance, and a coating method therefor, and have completed the present invention.

That is, the present invention provides (A) containing a carboxyl group, a hydroxyl group and an epoxy group in the same molecule, and having an acid value of 15 to 150 mgKOH/g, a hydroxyl value of 30 mgKOH/g or more, and an epoxy equivalent of 3000. ~
15000g/eq and number average molecular weight 3,000-3
0,000, (B) contains a carboxyl group, a hydroxyl group, and an epoxy group in the same molecule, and has an acid value of 2 to 10 mgKOH/g and a hydroxyl value of 30 mgK
OH/g or more, epoxy equivalent is 250-2500g/e
q and a number average molecular weight of 3,000 to 30,000, (C) an acrylic resin, (C) an amino resin, and (D) a glass having a particle size of 5 to 50 μ and surface treated with alumina and/or silica. The main ingredient is powder, and (
The molar ratio of carboxyl group of component A)/epoxy group of component (B) is 1/0.5 to 0.5/1, and component (C) is a component of (A), (B), and (C). Component (D) is contained in an amount of 10 to 40% by weight based on the total amount of (A), (B
) and (C) 30 to 1 per 100 parts by weight in total of components
A matte paint characterized by containing 20 parts by weight, and

[0008] The present invention relates to a coating method characterized in that, in the painting step of applying a colored paint and then applying a clear paint to the painted surface, the above-mentioned matte paint of (2) is used as the clear paint.

[0009] In the matte paint of the present invention, (A),
Since both components (B) have carboxyl groups, they have excellent compatibility not only with each other but also with component (C).

Component (A) has many carboxyl groups but few epoxy groups, while component (B) has many epoxy groups but few carboxyl groups. Therefore, during the polymerization of each of the above components, carboxyl groups and epoxy groups It has the advantage that almost no gelation or increase in molecular weight due to the reaction is observed.

[0011] A crosslinking reaction occurs between the functional groups of components (A) and (B) and between these and component (C), resulting in a coating film with excellent acid resistance, solvent resistance, weather resistance, and smoothness. form.

[0012] Since component (D) is blended, the matte coating film formed has a gloss value of 50% at 60 degrees specular reflectance.
The gloss value of the matte painted surface hardly changes even after polishing with wax or abrasive, and the water resistance, scratch resistance, weather resistance, and stain resistance are also better than conventional It is significantly superior to those using matting agents and is suitable as a matte coating film for automobile exterior panels.

In the present invention, "matte" means that the gloss value of the painted surface formed using the above-mentioned matte paint is JIS
60 degree specular reflectance based on K5400, 6, 7 is 50
% or less, particularly 30% or less. In the present invention, the coated surface of the matte paint itself has such a gloss value, forming a matte coating film.

[0014] The matte paint of the present invention will be explained in more detail below.

Component (A): Contains carboxyl group, hydroxyl group and epoxy group in the same molecule and has an acid value of 1
5-150mgKOH/g, hydroxyl value 30mgKOH
/g or more, epoxy equivalent is 3,000-15,000g
/eq and number average molecular weight of 3,000 to 30,000
Acrylic resin.

The acrylic resin [component (A)] having the above characteristics contains, for example, a carboxyl group-containing monomer, a hydroxyl group-containing monomer, and an epoxy group-containing monomer as essential components, and further contains other components as necessary. It can be obtained by copolymerizing monomers.

The carboxyl group-containing monomer is preferably a polymerizable monomer having one or more carboxyl groups and one polymerizable unsaturated bond in one molecule, particularly a carboxyl group-containing acrylic monomer. is acrylic acid,
Examples include methacrylic acid, maleic acid,
Examples include maleic anhydride, itaconic acid, and monoesterified products thereof, and these can be used alone or in combination of two or more.

The hydroxyl group-containing monomer is preferably a polymerizable monomer having one or more hydroxyl groups and one polymerizable unsaturated bond in one molecule, particularly a hydroxyl group-containing acrylic monomer.
Specifically, hydroxyethyl (meth)acrylate,
Hydroxyalkyl (meth)acrylates such as hydroxypropyl (meth)acrylate and hydroxybutyl (meth)acrylate; 1,4-butanediol mono(
Examples include meth)acrylate, ε-caprolactone adduct of hydroxyethyl (meth)acrylate, and ethylene and propylene adduct of hydroxyethyl (meth)acrylate, and these can be used alone or in combination of two or more.

The epoxy group-containing monomer is a polymerizable monomer having one or more epoxy groups (or glycidyl group) and one polymerizable unsaturated bond in one molecule, especially an epoxy group-containing acrylic monomer. are preferred, and specific examples include glycidyl methacrylate, glycidyl acrylate, methylglycidyl methacrylate, methylglycidyl acrylate, allyl glycidyl ether, etc.
One or more types of these can be used.

[0020] Further, the other monomer copolymerizable with the above monomer does not contain the above carboxyl group, hydroxyl group or epoxy group, has one polymerizable unsaturated bond, and has each of the above monomers. Monomers copolymerizable with the polymer are preferred, and specifically, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-
Butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2
-Ethylhexyl (meth)acrylate, stearyl (
Alkyl (meth)acrylates such as meth)acrylate, tridecyl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate; benzyl (meth)acrylate, phenyl (meth)acrylate, dimethylaminoethyl (meth)acrylate
Acrylates; esters of acrylic acid and methacrylic acid such as di(alkyl)aminoalkyl (meth)acrylates such as diethylaminoethyl (meth)acrylate; Furthermore, vinyl aromatic compounds such as styrene, α-methylstyrene, and vinyltoluene; acrylonitrile, methacrylnitrile, vinyl acetate, vinyl propionate, acrylamide, methacrylamide, methylol acrylamide, methylol methacrylamide, vinyl chloride, propylene, ethylene, C4
~C20 α-olefins and the like can also be used.

In component (A), the composition ratio of each of the above monomers is such that the acid value, hydroxyl value and epoxy equivalent of the copolymer (acrylic resin) formed from these monomers are within the above ranges. You just have to adjust it so that it is. Further, the copolymerization reaction using each monomer can be carried out by a conventional method, for example, any known polymerization method such as solution polymerization method, suspension polymerization method, bulk polymerization method, emulsion polymerization method, etc. can be used. be able to. At that time, as a polymerization initiator, azobisisobutyronitrile, 4,4'-azobis(4-cyanopentaic acid)
, benzoyl peroxide, t-butylperoxy-
2-ethylhexanoate, cumene hydroperoxide, potassium persulfate, hydrogen peroxide, 2,2
'-Azobis[2-methyl-N-(2-hydroxyethyl)propioamide], etc. can be used, and dodecyl mercaptan, mercaptoethanol, α-methylstyrene dimer, etc. can be used as a chain transfer agent, if necessary. You can also do it.

The reaction temperature is conveniently within the range of about 70 to about 130°C, preferably about 70 to 110°C, in order to suppress the reaction between carboxyl groups and epoxy groups during polymerization. Acrylic resin thus obtained [component (A)]
is 15 to 150 mgKOH/g, preferably 50 to 12
It can have an acid value within the range of 0 mg KOH/g. If the acid value is less than 15, the reactivity with the epoxy group of component (B) will decrease, and the acid resistance of the formed coating film will not improve.
) There is a tendency for compatibility with other components to decrease. In addition, it is important that the acrylic resin has a hydroxyl value of 30 mgKOH/g or more, preferably in the range of 35 to 100 mgKOH/g,
If it is smaller than g, the crosslinking reactivity with component (C) will be poor. Furthermore, the acrylic resin has an epoxy equivalent of 3,000 to
15,000g/eq, preferably 3,200-9,0
00g/eq, and the epoxy value is 15,00
When it is larger than 0, the compatibility with component (B) becomes poor,
On the other hand, if it is less than 3,000, the reaction between carboxyl groups and epoxy groups during the synthesis reaction of component (A) progresses, which tends to lead to high molecular weight and gelation. In addition, the number average molecular weight of component (A) is a value converted to polystyrene using GPC (gel permeation chromatography), and is 3,000
0-30,000, preferably 5,000-20,00
It can be within the range of 0. If the number average molecular weight of component (A) is less than 3,000, the weather resistance and water resistance of the coating film will be poor, and if it is greater than 30,000, the finished appearance will likely deteriorate.

Component (B): Contains carboxyl group, hydroxyl group and epoxy group in the same molecule and has an acid value of 2
~10mgKOH/g, hydroxyl value 30mgKOH/g
The acrylic resin has an epoxy equivalent of 250 to 2500 g/eq and a number average molecular weight of 3,000 to 30,000.

The acrylic resin [component (B)] having the above properties contains, for example, a carboxyl group-containing monomer, a hydroxyl group-containing monomer, and an epoxy group-containing monomer as essential components, and further contains other monomers as necessary. These monomers are preferably one or more selected from those exemplified in the explanation of component (A) above, and each of these monomers It is necessary to adjust the composition ratio of the acrylic resin [component (B)] so that the acid value, hydroxyl value, and epoxy equivalent of the obtained acrylic resin [component (B)] are within the above ranges. Further, copolymerization of these monomers can be carried out in the same manner as described for component (A) above.

[0025] It is important that the acrylic resin as component (B) has an acid value within the range of 2 to 10 mgKOH/g; if the acid value is less than 2, the compatibility with component (A) will be poor. On the other hand, if it exceeds 10, the reaction between the carboxyl group and the epoxy group will proceed during the synthesis of the component (B), resulting in higher molecular weight and gelation. Further, the hydroxyl value of the acrylic resin is 30 mgKOH/g or more, preferably 35 to
If it is within the range of 100 mgKOH/g and the hydroxyl value is less than 30, the crosslinking reactivity with component (C) will decrease.

Furthermore, the epoxy equivalent of the acrylic resin is preferably in the range of 250 to 2,500, preferably 300 to 1,500, and the epoxy equivalent is 2,50.
When it is more than 0, the reactivity with carboxyl groups decreases, and the acid resistance of the coating film is not improved.On the other hand, when it is less than 250, the compatibility with component (A) tends to decrease.

[0027] Acrylic resin [component (B)] is 3,000
~30,000, preferably 5,000~20,00
If the number average molecular weight is less than 3,000, the weather resistance and water resistance of the coating film will be poor, and if it is greater than 30,000, the finished appearance of the coating film will deteriorate. Cheap.

Component (C): Amino resin The amino resin includes, for example, a methylolated amino resin synthesized from at least one of melamine, urea, benzoguanamine, etc. and formaldehyde, and further includes methanol, ethanol, propanol. , isopropanol,
An amino resin in which part or all of the methylol group is alkyl etherified with a lower monohydric alcohol such as butanol can also be used as an amino resin.

Organic solvents and/or water are suitable as the solvent or dispersion medium that can be used in mixing the components (A), (B) and (C).

The composition ratios of components (A), (B), and (C) are not strictly limited and may vary depending on the type and use of each component, but in general, first, ( The ratio of component A) to component (B) is the carboxyl group of component (A)/
(B) Based on the molar ratio of epoxy groups in component 1/0.5
It can be within the range of ~0.5/1, preferably 1/0.6 ~ 0.6/1; outside this range, the solvent resistance and adhesion of the coating film tend to decrease. The blending ratio of component (C) is 10 to 40% by weight, preferably 15 to 30% by weight based on the total amount of components (A), (B), and (C).
If the content of component (C) is less than 10% by weight, the crosslinking reaction between component (C) and the hydroxyl groups of components (A) and (B) will be insufficient, and the solvent resistance of the coating film will be reduced. On the other hand, if the amount exceeds 40% by weight, the acid resistance of the coating film tends to deteriorate.

Component (D): Glass powder having a particle size of 5 to 50 μm and surface-treated with alumina and/or silica.

First, it is most preferable that the glass powder to be surface-treated has a spherical shape, but other shapes are also possible, and a hollow shape can also be used. If a large amount of hollow glass powder is added, the transparency of the clear coating film tends to decrease, so it is not recommended to apply this product to dark colored coating surfaces, but it can be applied to light colored coating surfaces without any problem. . Glass powder can be produced by a method known per se, and its composition includes SiO2, Al2O3, Na2O, K
Soda lime glass whose main composition is 2 O, MgO and CaO. Particularly preferred is a low-alkali type glass powder in which the content of Na2O in the glass powder is 1% by weight or less.

Alumina and/or silica for surface treatment of the glass powder are both inorganic, and first, an aqueous solution of an aluminum salt and/or silicate is added to an aqueous slurry of glass powder to form a glass powder. A film made of these salts is formed on the surface of the powder. The temperature of this system may be room temperature, but may be heated as appropriate. Next, the glass powder is neutralized with an acid or alkali to deposit a hydrate of the treatment agent on the surface of the glass powder, and soluble salts produced as by-products are washed and removed, and then dried. The film deposited on the surface of the glass powder particles is preferably a film of Al2O3.nH2O.SiO2, which covers the surface of the glass powder. Glass powder may be treated with alumina alone, but combined treatment with alumina and silica is preferred.

The glass powder is used to make the coating film matte and has a particle size of 5 to 50 μm, preferably 8 μm.
It is necessary to use a coating material with a particle diameter of ~25μ, and if it is smaller than 5μ, the matting effect will be reduced, and if it is larger than 50μ, the smoothness and stain resistance of the coated surface will be reduced, so both are not preferred. In particular, when a layer of 8 to 25 μm is used, the matting effect is remarkable.

The blending amount of component (D) is per 100 parts by weight of the total resin solid content in components (A), (B) and (C).
30 to 120 parts by weight (preferably 40 to 110 parts by weight)
However, the amount to be added is determined by the degree of matteness. For a matte glass with a 60 degree specular reflectance of 10 to 30%, the amount of low alkali glass powder to be blended is 50 to 100 parts by weight. Further, the water resistance of the glass powder blended in the present invention is further improved when the glass powder is further organically treated. Glass powder treatments include amino silane, glycid silane, and acrylic silane. Among them, amino silane and glycid silane are better.

The matte paint of the present invention may further contain a curing catalyst, a viscosity modifier (for example, organic montmolinite, microgel, polyamide, etc.), a coating surface modifier (for example, silicone type, acrylic resin type, etc.), and ultraviolet light. Absorbers, blocked polyisocyanate compounds, color pigments, metallic pigments, interference pigments, etc. can be blended in conventional amounts.

The curing catalyst may be a phosphoric acid catalyst such as dibutyl phosphoric acid or an amine block strong acid catalyst such as dodecylbenzenesulfonic acid or p-toluenesulfonic acid in order to promote the crosslinking reaction between the hydroxyl group and the amino resin. For example, quaternary ammonium salts such as tetrabutylammonium chloride and quaternary phosphonium salts such as tetraphenylphosphonium chloride are suitable for promoting the crosslinking reaction between carboxyl groups and epoxy groups. ing.

The matte paint of the present invention can be obtained by dissolving or dispersing the above components in an organic solvent. Its form includes organic solvent type, high solid type and non-aqueous dispersion type, and can be adjusted by methods known per se.

[0039] The matte coating method of the present invention is a coating method in which a cross-linked curing type colored paint is applied and a cross-linked curing type clear paint is applied to the coated surface, and the above-mentioned matte paint is used as the clear paint. This is a matte painting method characterized by:

[0040] The crosslinking-curable colored paint used in this method is a paint containing as essential components a resin composition that undergoes a three-dimensional crosslinking reaction and crosslinking and hardening at room temperature or by heating, and a colored pigment.

The above-mentioned resin composition basically contains a base resin and a crosslinking agent as main components. Examples of base resins include acrylic resins, polyester resins, and alkyd resins having crosslinkable functional groups, and examples of crosslinking agents include methylolated and/or alkyl etherified melamine resins and urea resins, as well as polyisocyanate compounds (blocked products are also available). ) can also be used. Moreover, a self-curing resin that does not use a crosslinking agent can also be used as the resin composition.

Furthermore, a vinyl copolymer containing as monomer components a specific polysiloxane macromonomer having two or more free functional groups such as a hydroxyl group or an alkoxyl group and a vinyl monomer containing an oxirane group, or A mixture of a polymer containing a polysiloxane macromonomer as an essential monomer component and a polymer containing an oxirane group-containing vinyl monomer as an essential monomer component is used as a base resin;
A coating composition containing at least one selected from Lewis acids, protonic acids, metal alkoxides, organometallic compounds, and compounds having Si-O-Al bonds as a curing catalyst is a polysiloxane-based monomer component. A silanol group present in a macromonomer or a silanol group generated by hydrolysis of an alkoxyl group in the macromonomer,
The oxirane group in the oxirane group-containing vinyl monomer, which is another monomer component, becomes a crosslinking functional group, and even at low temperatures below 100°C, the curing reaction proceeds simultaneously on the surface and inside of the coating film, and the cured product There is little difference in the degree of hardening between the surface and the inside, and it is difficult to cause distortion, so it is suitably used in the present invention.

[0043] As the coloring pigment, one or more types selected from ordinary coloring pigments such as titanium white, carbon black, and phthalocyanine blue, and metallic pigments can be used.

The colored paint used in the present invention is preferably one obtained by dissolving or dispersing the above resin composition and colored pigment in an organic solvent and/or water. Its forms include organic solution type, high solid type, non-aqueous dispersion type, aqueous solution type, and water dispersion type, and can be adjusted by methods known per se. It may also be a powder type paint.

[0045] The matte painting finishing method of the present invention involves applying the above-mentioned colored paint after subjecting the object to be coated (metal and/or plastic automobile exterior panel) to surface treatment, primer coating, and intermediate coating as necessary. do. Although the coating film thickness is not limited, it is preferably 10 to 30 μm based on the cured coating film. After the colored coating film is crosslinked and cured at room temperature to 160°C, or in an uncured state, the above-mentioned matte clear paint is applied to the surface of the coating film. The thickness of the clear coating film is suitably in the range of 20 to 100 μm based on the cured coating film. After applying the matte clear paint, it is preferable to cure it at room temperature to 160°C. The matte clear coating film may be a single layer, but may have two or more layers if necessary.

The matte coating formed by the method of the present invention has a gloss value that can be easily adjusted to 50% or less at 60 degree specular reflectance, and even when polished with wax or abrasive, the gloss value of the matte coating remains unchanged. The gloss value hardly changes, and
The acid resistance, water resistance, scratch resistance, weather resistance, and stain resistance are also significantly superior to those using conventional matting agents, making it particularly suitable as a matte coating film for automobile exterior panels. Hereinafter, the present invention will be explained in more detail with reference to production examples and examples. Note that parts and % indicate parts by weight and % by weight.

I Production Example (1) Production of the matte paint (A) component: 450 parts of xylene and 150 parts of n-butanol were charged into a 4-necked flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube, and heated to 100°C. Warm up. After adding the monomer components shown in Table 1 dropwise over a period of 4 hours, the mixture was kept at 100°C for 2 hours, and then diluted with 400 parts of xylene to form an acrylic copolymer with a solids content of 50% ( a-1) to (a-4) were obtained. (2) Production of matte paint (B) component: 300 parts of xylene, n
- Add 300 parts of butanol and heat to 100°C. After adding the monomer components shown in Table 1 dropwise to this for 4 hours,
The acrylic copolymer with a solids content of 50% (
b-1) to (b-4) were obtained.

[0048]

[Table 1]

II Example and Comparative Example II-1
Amino resin [(
Component C)] and glass powder [Component (D)] were blended using a sand mill or the like, and the clay was adjusted to produce a matte clear paint.

Example 1 Matte clear paint (C-
1): (a-1)

80 copies (b-1)

80〃 60% Yuban 20SE

33 (manufactured by Mitsui Toatsusha)
Butylated melamine) Glass powder (Note-1)

100 Surface conditioner

0.1〃 (BYK-300 manufactured by BYK-CHEM Co., Ltd.) Ultraviolet absorber

1.0〃 (Tinuvin 900 manufactured by Ciba Geigy) The above mixture was added to Swasol 1
000 and adjusted to a viscosity of 25 seconds in a Ford cup (#4) at 20°C. (Note-1) Glass powder Glass powder obtained by alumina treatment of soda-lime glass powder (spherical shape, particle size 10μ, manufactured by Toshiba Ballotini Corporation, Microbeads MB-10).

Example 2 Matte clear paint (C-2
): (a-2)

90 copies (b-2)

70〃 Cymel 303

20〃 (Mitsui Cyanamide, Flumethoxymelamine) Glass powder (Note 2)

90〃 NACURE
5225
2〃 (Dodecylbenzenesulfonic acid amine neutralized product manufactured by King Co.)
Surface conditioner (BYK-300)
0.1〃
Ultraviolet absorber (Tinuvin 900)
1.0 The above mixture was produced in the same manner as in Example 1. (Note-2) Glass powder microbeads MB-10 treated with alumina and silica, and further treated with amino and silane.

Example 3 Matte clear paint (C-3
): (a-3)

80 copies (b-3)

80〃 60% Yuban 20SE

33 Glass powder (Note 3)

110 Surface conditioner (BYK-
300)
0.1 Ultraviolet absorber (Tinuvin 900
)
1.0 Tetrabutylammonium chloride
0.05 The above mixture was prepared in the same manner as in Example 1. (Note-3) Glass powder low alkali glass powder (manufactured by Toshiba Ballotini Corporation, E
MB-10 (spherical, particle size 10μ) was treated with alumina and silica, and then organically treated with amino and silane.

Comparative Example 1 Clear paint (C-4):
(a-1)
1
00 copies (b-1)

30〃 60% Yuban 20SE

40 Glass powder (Note 1)

100 Surface conditioner (BYK-300
)
0.1 UV absorber (Tinuvin 900)
1.
0 The above mixture was produced in the same manner as in Example 1.

Comparative Example 2 Clear paint (C-5):
(a-4)

80 copies (b-4)

80〃 60% Yuban 20SE

30 Glass powder (Note 1)

100 Surface conditioner (BYK-30
0)
0.1 UV absorber (Tinuvin 900)
1
．． 0 The above mixture was produced in the same manner as in Example 1.

Example 4 Matte colored paint (S-1)
: Titanium white JR-701
5
0 parts (manufactured by Teikoku Kako Co., Ltd., titanium dioxide) (a
-3)
8
0 copies (b-2)

80〃 60% Yuban 20SE

33〃 Glass powder (Note-3)

100 Surface conditioner (BYK-300
)
Dilute the mixture of 0.1〃 with Swasol 1000,
The viscosity was adjusted to Ford Cup (#4) 25 seconds.

II-2 Matte coating method An electrodeposited coating film and an intermediate coating film were formed on a mild steel plate treated with zinc phosphate, and the following metallic paint was applied (film thickness: 20 μm in cured film thickness).
After leaving it at room temperature for 5 minutes, apply the above matte clear paints (C-1) to (C-5) on the painted surface (film thickness: 4 as above).
0 μ) and 140° C. for 30 minutes to cure both coatings simultaneously. The performance test results of the obtained coating film are shown in Table 2.

(Metallic paint): Acrylic resin

100 parts (Dainippon Ink & Chemicals Co., Ltd. Acrydik 47-712) Butylated melamine

60 parts (Mitsui Toatsu Co., Ltd., Yuban 20SE-60) Aluminum paste

10 parts (manufactured by Toyo Aluminum Co., Ltd., Aluminum Paste 55-519) The above was mixed with Ford Cup No. 1 using a mixed solvent consisting of 30 parts of Swasol #1000 and 70 parts of toluene. 4 (20℃) 14
Adjusted to seconds.

II-3 Colored paint: The above colored paint (S-1) was applied to a zinc phosphate treated steel sheet which had been electrodeposited and intermediate coated in the same manner as above (coating film thickness: 40 μm as above), and It was cured by heating at ℃ for 30 minutes. The performance test results of the obtained coating film are shown in Table 2. Table 2 also lists the blending ratio of each component of each paint.

[0059]

[Table 2] After washing, the coated surface was observed and evaluated according to the following criteria. ○: No change at all. △: There is no abnormality on the painted surface, but a slight step is observed at the boundary between the immersed area and the non-immersed area. ×: Painted surface turned white. Recoat adhesion: After baking each sample at 160°C for 30 minutes, apply the same topcoat (base coat/clear coat in the case of metallic) on top and bake at 140°C for 30 minutes, then apply 100 crosscuts at 1mm intervals. and use sellotape to determine whether or not it has peeled off. ○: No peeling observed at all. △: Slight peeling is observed. ×: Significant peeling is observed.

Water resistance: After being immersed in warm water at 40°C for 240 hours, the coated surface was washed with water and evaluated based on the following criteria. ○: No change at all. △: Slightly glossy. ×: Painted surface turned white.

Finished appearance: Visual judgment. Stain resistance: 5×
Place 1 g of JIS Class 15 contamination dust on a 5 cm coated plate, spread it evenly by sweeping it 20 times with a brush,
It was left standing at ℃ for 24 hours. Next, this was washed under running water using a clean brush, and the degree of contamination was examined. ◎: No stains observed at all. ○: Slight stains are observed. △: Considerable stains are observed. ×: Significant stains are observed.

Scratch resistance: A dyeing rub fastness test (manufactured by Daiei Kagaku Seiki Seisakusho) was used. A polishing powder (Daruma Cleanser) was hardened with water, placed on the painted surface, pressed with a testing machine terminal, and rubbed back and forth 25 times with a load of 0.5 kg applied. After washing with water, the degree of scratches was evaluated in four stages: ◎, ○, △, and ×.

Accelerated weathering resistance: According to the QUV accelerated weathering test using an accelerated weathering tester manufactured by Q Panel Co., Ltd. Test conditions: UV irradiation 16H/60℃ water condensation
Conclusion The coating film after testing for 3000 hours (125 cycles) with 8H/50°C as one cycle was evaluated. ◎: Maintains almost the same luster as at the initial stage. ○: There is a slight decrease in gloss, but there are no defects such as cracking or whitening. Δ: Decrease in gloss and whitening phenomenon observed. ×: Significant reduction in gloss, cracking, and whitening phenomenon were observed.
It is a failure.

Impact resistance: Tested using a DuPont impact tester with a firing pin tip radius of 1/2 inch and a dropped bell weight of 500 g. Indicates the maximum height without cracks on the painted surface (in 5cm increments).

Claims (2)

[Claims] Claim 1: (A) a carboxyl group in the same molecule;
Contains hydroxyl and epoxy groups and has an acid value of 15 to 1
50mgKOH/g, an acrylic resin with a hydroxyl value of 30mgKOH/g or more, an epoxy equivalent of 3000 to 15000g/eq, and a number average molecular weight of 3,000 to 30,000, (B) a carboxyl group, a hydroxyl group, and an epoxy group in the same molecule. group and has an acid value of 2 to 10 mgK
OH/g, an acrylic resin having a hydroxyl value of 30 mgKOH/g or more, an epoxy equivalent of 250 to 2500 g/eq, and a number average molecular weight of 3,000 to 30,000, (C
) an amino resin, and (D) a glass powder having a particle size of 5 to 50 μ and surface-treated with alumina and/or silica as the main components, and a carboxyl group of the component (A)/a glass powder of the component (B). Epoxy group molar ratio is 1/0.5~0
．． 5/1 and contains component (C) in an amount of 10 to 40% by weight based on the total amount of components (A), (B) and (C), and contains component (D) in an amount of (A), (B). ) and (C) in an amount of 30 to 120 parts by weight per 100 parts by weight in total. 2. A matte coating method, characterized in that in the painting step of applying a colored paint and then applying a clear paint to the painted surface, a matte paint selected from the paints according to claim 1 is used as the clear paint. .