JP3394639B2 - Paint composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating composition for finishing unevenness, which is capable of forming a coating film having an unevenness pattern which is excellent in workability and blocking resistance and is excellent in designability, and in particular, a precoated coated steel sheet for processing of articles. The present invention relates to a coating composition suitable for use, and a coated metal plate obtained by coating the coating composition.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As a top coat paint for coated steel sheets that are processed into articles such as home electric appliances such as VTRs, radio-cassettes, microwave ovens, etc., the composition of which is a polyester resin as a base resin and a melamine resin or an isocyanate compound as a curing agent. A paint for finishing unevenness, in which organic resin fine particles are mixed with an organic solvent-based paint containing a resin as a resin component, is used. Among them, paints in which a curing catalyst is mixed with a mixture of a melamine resin, especially a methyl etherified methylol melamine resin as a curing agent are often used.

[0003] The coated steel sheet coated with the above-mentioned conventional paint is generally formed by press molding or the like regardless of the four seasons when it is processed into a container. Workability is extremely important. For example, since the molding process in cold regions is often performed at 0 ° C, the glass transition temperature of the coating film is 50 ° C.
Under the present circumstances, unless it is below, sufficient workability cannot be obtained.

On the other hand, when the glass transition temperature of the coating film is lowered with an emphasis on workability, when the coated steel sheet is deposited in a sheet shape or wound into a coil shape, the load is applied particularly at high temperature in summer. There is a problem that the coating film is likely to cause blocking.

As described above, a paint for finishing unevenness which can form a coating film satisfying both the workability at low temperature and the blocking resistance at high temperature has not been found at present, and the development of a paint satisfying these is not found. Is an urgent task.

[0006] The inventors of the present invention have earnestly studied to obtain a coating material for finishing unevenness which can form a patterned coating film satisfying both processability at low temperature and blocking resistance at high temperature. The inventors have found that the above objects can be achieved by blending cellulose acetate butyrate in a coating for finishing unevenness, thus completing the present invention.

[0007]

That is, the present invention is as follows.
(A) Hydroxyl group-containing polyester resin 60 to 95 parts by weight and (B) amino resin curing agent 5 to 40 parts by weight in total 1
(C) average particle size 0.2 to 80 μm based on 100 parts by weight
A coating composition comprising 2 to 40 parts by weight of organic polymer fine particles of m and 1 to 15 parts by weight of (D) cellulose acetate butyrate.

The present invention also relates to 2. A coated metal plate comprising a metal plate and a cured coating film of the coating composition according to item 1 formed on the metal plate with or without a primer coating film interposed therebetween.

In the composition of the present invention, the polyester resin as the component (A) is a polyester resin containing a hydroxyl group, and is an oil-free polyester resin, an alkyd resin, or a modified product of these resins, for example, a urethane-modified polyester resin. , Urethane-modified alkyd resin, epoxy-modified polyester resin, or the like.

The above polyester resin has a number average molecular weight of 1,000 to 3 from the viewpoints of processability of the resulting coating film, coating film hardness, solvent resistance, stain resistance, and ease of handling the resin.
5,000, glass transition temperature -25 to 35 ° C, hydroxyl value 3 to 100 mgKOH / g, number average molecular weight 1,500 to 33,000, glass transition temperature -20
More preferably, it has a hydroxyl value of 3 to 70 mgKOH / g at -25 ° C. In the present invention, the glass transition temperature (T
g) is based on differential thermal analysis (DSC), and the number average molecular weight is measured by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene.

The glass transition temperature of the polyester resin is more preferably 30 ° C. or lower when the workability is emphasized, and is preferably 15 ° C. or higher when the hardness is emphasized.

The above oil-free polyester resin is mainly an esterified product of polybasic acid and polyhydric alcohol,
As the polybasic acid, one or more dibasic acids selected from phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid, fumaric acid, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and the like, and Lower alkyl esterified products of these acids are mainly used, and if necessary, monobasic acids such as benzoic acid, crotonic acid, p-tert-butylbenzoic acid, trimellitic anhydride, methylcyclohexene tricarboxylic acid, pyromellitic anhydride. A trivalent or higher polybasic acid such as an acid is used, and as the polyhydric alcohol, ethylene glycol, propylene glycol, diethylene glycol, butanediol, neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, 1, Dihydric alcohol such as 6-hexanediol is mainly used Glycerin, trimethylolethane, trimethylolpropane,
A trihydric or higher polyhydric alcohol such as pentaerythritol can also be used in combination. The esterification or transesterification reaction of both components can be performed by a known method. As the acid component,
Especially preferred are terephthalic acid, isophthalic acid, and lower alkyl esters of these acids.

The alkyd resin is obtained by reacting an oil fatty acid by a known method in addition to the acid component and alcohol component of the oil-free polyester resin, and examples of the oil fatty acid include coconut oil fatty acid, soybean oil fatty acid and flaxseed oil. Examples thereof include oil fatty acid, safflower oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, and tung oil fatty acid. The oil length of the alkyd resin is preferably 30% or less.

The urethane-modified polyester resin is the above-mentioned oil-free polyester resin, or a low-molecular-weight oil-free polyester resin obtained by reacting an acid component and an alcohol component during the production of the above oil-free polyester The reaction is carried out by a known method. The urethane-modified alkyd resin is obtained by reacting the above-mentioned alkyd resin or a low-molecular-weight alkyd resin obtained by reacting each component during the production of the above-mentioned alkyd resin with a polyisocyanate compound by a known method. Examples of the polyisocyanate compound used when producing the urethane-modified polyester resin and the urethane-modified alkyd resin include hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate, 4,4′-
Diphenylmethane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 2,4,6
-Triisocyanatotoluene and the like.

As the epoxy-modified polyester resin,
Using a polyester resin produced from each component used in the production of the polyester resin, a reaction product of a carboxyl group of this resin and an epoxy group-containing resin, a hydroxyl group in the polyester resin and a hydroxyl group in the epoxy resin polyisocyanate A reaction product obtained by a reaction such as addition, condensation or grafting of a polyester resin and an epoxy resin, such as a product bonded via a compound, can be mentioned.

Examples of the amino resin curing agent which is the component (B) in the composition of the present invention include melamine resin, urea resin, benzoguanamine resin, spiroguanamine resin, and the like. Among them, melamine resin is preferable, and methyl ether is particularly preferable. A melamine resin, or a mixture of a methyl etherified melamine resin and a butyl etherified melamine resin is preferable.

In the methyl etherified melamine resin, a part or all of the methylol groups in the methylolated melamine resin, which is an addition reaction product (monomer or multimer) of melamine and formaldehyde, is etherified only with methanol. Methylated melamine resin and part or all of the methylol groups in the methylolated melamine resin are mixed with a mixed alcohol of methanol and another alcohol having 2 to 4 carbon atoms, for example, ethanol, isopropanol, n-butanol, isobutanol, etc. Both etherified melamine resins are included.

The above-mentioned methyl etherified melamine resin is a polyester resin in which the number of methyl etherified methylol groups is 3.0 or more on average per triazine nucleus and the number average molecular weight is 1,000 or less. (A)
It is preferable from the viewpoints of compatibility with, the stain resistance of the resulting coating film, processability, and the like.

Commercially available products of the above-mentioned preferred methyl etherified melamine resins are, for example, Cymel 303 and 32.
5, 327, 350, 730, 736, 73
8 [all manufactured by Mitsui Cytec Co., Ltd.], Melan 52
2 and 523 [all manufactured by Hitachi Chemical Co., Ltd.], Nikarac MS001, and MX650 [Sanwa Chemical Co., Ltd.]
Manufactured by Sumitomo Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Regimin 740, and 747 [all manufactured by Monsanto Co., Ltd.], and the like; Cymel 232, 266,
The same XV-514 [all manufactured by Mitsui Cytec Co., Ltd.],
Nikarac MX500, MX600, MS95 (all manufactured by Sanwa Chemical Co., Ltd.), Regimin 753, 7
Examples include mixed etherified melamine resins of methyl ether and butyl ether such as 55 (all manufactured by Monsanto).

The butyl etherified melamine resin used by mixing with the methyl etherified melamine resin is one of the methylol groups in the methylolated melamine resin which is an addition reaction product (monomer or multimer) of melamine and formaldehyde. A part or the whole is etherified with n-butyl alcohol or isobutyl alcohol, and the number average molecular weight is in the range of 800 to 8,000 from the viewpoints of the paint stability of the obtained paint and the stain resistance of the obtained paint film. Is more preferable, and it is more preferable that it is in the range of 1,000 to 3,000.

Commercially available products of the above-mentioned butyl etherified melamine resin are, for example, Uban 20SE and 2
8SE [all manufactured by Dainippon Ink and Chemicals, Inc.], Super Beckamine J-820-60, and L-117-6
0, L-109-65, G-821-60, 47
-508-60, L-118-60 (all manufactured by Mitsui Toatsu Co., Ltd.) and the like can be mentioned.

By using the methyl etherified melamine resin in combination with the butyl etherified melamine resin, the butyl etherified melamine resin, which has a poor compatibility with the polyester resin, is transferred to the surface of the coating film, and the cured film is excellent in stain resistance. It is also advantageous for coating hardness. The cross-linking inside the coating film can be carried out mainly by the methyl etherified melamine resin, which is also advantageous in terms of processability.

In the composition of the present invention, when a methyl etherified melamine resin or a mixture of this resin and another amino resin is used as the component (B), an acid catalyst is also used as a curing catalyst to accelerate the curing reaction. Preferably. Examples of the curing catalyst include strong acids and neutralized products of strong acids. Typical examples are p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid,
Examples thereof include sulfonic acid compounds that are strong acids such as dinonylnaphthalenedisulfonic acid and amine neutralized products of these sulfonic acid compounds. Among these, the amine neutralized product of p-toluenesulfonic acid and / or the amine neutralized product of dodecylbenzenesulfonic acid is preferable from the viewpoints of the stability of the coating material, the reaction accelerating effect, and the physical properties of the resulting coating film. . The amount of the curing catalyst used is preferably 0.1 to 3.0 parts by weight as a value converted to the amount of the acid compound with respect to 100 parts by weight of the total of the components (A) and (B). Is. The organic polymer fine particles as the component (C) in the composition of the present invention are organic polymer fine particles having an average particle diameter of 0.2 to 80 μm, preferably 3 to 50 μm,
It is present as particles even after curing without melting and spreading at the time of curing of the coating material, and it is possible to give unevenness to the coated surface. Examples of the organic polymer resin species of the fine particles include polyamide resin (nylon 11, nylon 12, etc.), silicone resin, polymethyl methacrylate, polystyrene, methyl methacrylate-butadiene-styrene terpolymer, polyacrylonitrile, polyvinylidene fluoride. Examples thereof include resins, melamine resins, polypropylene resins, and phenol resins. Among them, polyamide resins are preferable in terms of adhesion, corrosion resistance, and scratch resistance.

Examples of the cellulose acetate butyrate as the component (D) in the composition of the present invention include CAB-381-0.1 and CA manufactured by Eastman Chemical Company.
B-381-20, CAB-500-1, CAB-50
0-5, CAB-531-1, CAB-551-0.0
1, CAB-551-0.2, CAB-553-0.4
And the like, CAB-500-1, CAB-500-5, CAB from the viewpoint of solubility in a solvent.
-531-1, CAB-551-0.01, CAB-5
Those having a high degree of butylation such as 51-0.2 and CAB-553-0.4 are preferable. The component (D) can be dissolved in a solvent in advance and added as a solution. By blending the component (D), it is possible to improve the blocking resistance while maintaining the processability.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION In the composition of the present invention, (A),
The blending amounts of the components (B), (C) and (D) are as follows.

The mixing ratio of the polyester resin (A) and the amino resin curing agent (B) is (A) / (solid content weight ratio).
(B) is in the range of 60/40 to 95/5, preferably 70/30 to 85/15. In the total 100 parts by weight of the component (A) and the component (B), the component (A) is 6
If the amount is less than 0 parts by weight [the amount of the component (B) exceeds 40 parts by weight], the processability of the coating film decreases, while the amount of the component (A) is 9 parts by weight.
If the amount exceeds 5 parts by weight [the amount of the component (B) is less than 5 parts by weight], the resulting coating film has poor blocking resistance, stain resistance, hardness, solvent resistance, and the like.

The blending amount of the organic polymer fine particles (C) is
It is in the range of 2 to 40 parts by weight, preferably 3 to 20 parts, relative to 100 parts by weight of the total of the components (A) and (B).
The range is parts by weight. When the compounding amount of the component (C) is less than 2 parts by weight, the unevenness is sparse and the design property of the coating film is deteriorated. On the other hand, when it exceeds 40 parts by weight, the coating workability of the coating material is deteriorated and the obtained coating is obtained. The workability of the film is reduced.

The blending amount of cellulose acetate butyrate (D) is in the range of 1 to 15 parts by weight, preferably 2 to 8 parts by weight, based on 100 parts by weight of the total of the components (A) and (B). It is a range of parts. If the blending amount of the component (D) is less than 1 part by weight, the effect of improving the blocking resistance is not sufficient, while if it exceeds 15 parts by weight, the curability of the coating film is poor and the adhesion of the coating film decreases. However, the non-volatile content at the time of coating of the paint is lowered, and the workability of coating is deteriorated.

The coating composition of the present invention comprises the above (A),
Although it may be composed only of the components (B), (C) and (D), it is usually made to contain an organic solvent from the viewpoint of handling and coatability. As the organic solvent, those capable of dissolving or dispersing the respective components (A), (B), (C) and (D) can be used, and specific examples thereof include methyl isobutyl ketone, cyclohexanone and isophorone. Ketone-based solvent; Toluene, xylene, high-boiling petroleum hydrocarbon, and other hydrocarbon-based solvent; Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and other ether-based solvent; Ethyl acetate, butyl acetate, Ethylene glycol mono Examples thereof include ester solvents such as ethyl ether acetate and diethylene glycol monoethyl ether acetate, which may be used alone or in admixture of two or more.

The coating composition of the present invention can be used as a clear coating containing no pigment, but can also be used as an enamel coating containing a coloring pigment. Coloring pigments that can be used in the paint field, for example, organic coloring pigments such as cyanine blue, cyanine green, and organic red pigments such as azo and quinacridone; titanium white, titanium yellow, red iron oxide, carbon black, yellow lead, various baked pigments. Inorganic color pigments such as can be used. In addition, the composition of the present invention contains, if necessary, rust preventive pigments such as strontium chromate, zinc chromate, barium chromate and calcium chromate; extender pigments such as talc, clay, silica, mica and alumina; fillers. , Additives, etc. may be contained.

The addition of the rust preventive pigment is particularly effective when the composition of the present invention is applied on a metal plate without a primer coating, and the corrosion resistance of the coated metal plate can be improved. The amount of the rust preventive pigment compounded is preferably 20 parts by weight or less based on 100 parts by weight of the total amount of the polyester resin (A) and the melamine resin curing agent (B). It is preferably in the range of 1 to 20 parts by weight.

Examples of objects to be coated with the coating composition of the present invention include cold-rolled steel sheet, hot-dip galvanized steel sheet, galvanized steel sheet, alloy-plated steel sheet, aluminum sheet, stainless steel sheet, copper sheet, copper-plated steel sheet, tin-plated steel sheet and the like. The metal plate or a metal plate obtained by subjecting these metal plates to a surface treatment such as a phosphate-based or chromate-based is suitable, but it is also applicable to plastics, wood, cement, etc. Can be applied directly to these substrates or via a primer coating. As a primer,
Examples thereof include epoxy type, polyester type, acrylic type and modified primers thereof, and the polyester primer is particularly preferable in terms of processability. Although the film thickness of the primer coating film is not particularly limited, it is usually 1 to 15 μm.
The range is m, preferably 2 to 8 μm.

The coated metal plate in the present invention is the above-mentioned metal plate or a metal plate obtained by subjecting these metal plates to a surface treatment as an article to be coated. A cured coating film of the coating composition of the present invention is formed with or without a film.

The coating composition of the present invention can be applied by curtain flow coating, roll coating, dip coating, spray coating, etc., and usually the coating film thickness after drying is 5 to 30.
Painted to be in the micron range. Further, the curing of the above-mentioned coating material can be appropriately set from the temperature of the coating material and the baking time. Range, especially 200
A range of 30 to 70 seconds at ˜230 ° C. is suitable.

[0035]

EFFECT OF THE INVENTION The composition of the present invention is a polyester-amino resin-based uneven finish coating, which is blended with cellulose acetate butyrate for both low-temperature processability and high-temperature blocking resistance which have hitherto been unattainable. The coated steel sheet coated with this paint exhibits excellent performance in both workability at low temperatures in cold regions in winter and blocking resistance in stacking at high temperatures in summer. . INDUSTRIAL APPLICABILITY The composition of the present invention is particularly suitable as a top coat paint for coated steel sheets that are processed into articles such as home electric appliances that require designability because they can form an uneven finish coating film with excellent designability.

[0036]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the following, "parts" and "%" are based on weight.

Examples 1 to 8 and Comparative Examples 1 to 7 Using the composition shown in Table 1 below, coating was performed to obtain each top coating composition. Kansai Paint Co., Ltd. KP color 8620 primer (polyester primer for pre-coated steel sheet) was coated on chromate-treated electrogalvanized steel sheet with a thickness of 0.5 m / m to a dry film thickness of 5 μm, and the material reached temperature of 22
It was baked for 45 seconds at 0 ° C to obtain a primer-coated steel sheet. On each primer-coated steel sheet, each top-coating material obtained as described above was coated with a bar coater to a dry film thickness of about 18 μm, and baked for 60 seconds so that the maximum temperature reached by the material was 220 ° C. Got Various tests were conducted on the obtained coated steel sheet.

The test results are shown in Table 2. The amounts of the polyester resin and the melamine resin in Table 1 are indicated by the weight of the solid content, and the amount of the curing catalyst is indicated by the weight in terms of the amount of each sulfonic acid compound. When the examples and comparative examples were made into paints, carbon black as a black pigment was dispersed, and cellulose acetate butyrate was mixed with methyl ethyl ketone / toluene / xylene / butyl acetate = 2/1/1/1. It was dissolved in a solvent and used as a 20% solid content solution. Furthermore, a mixed solvent of cyclohexanone / Swasol 1500 (manufactured by Cosmo Oil Co., Ltd., aromatic petroleum high boiling point solvent) = 60/40 (weight ratio) was used for adjusting the viscosity of the paint. When painting, adjust the viscosity of the paint with a Ford Cup ^# 4 for about 100 seconds (2
The temperature was adjusted to 5 ° C).

Example 9 Example 1 was repeated except that the primer composition was not coated on the chromate-treated electrogalvanized steel sheet, but the coating composition having the composition shown in Table 1 below was directly coated on the steel sheet.
The same procedure was followed to obtain a top-coated steel sheet on which a top-coat coating film was formed. Various tests were conducted on the obtained coated steel sheet. The results are shown in Table 2.

[0040]

[Table 1]

[0041]

[Table 2]

[Notes] in Table 1 are as follows.

The polyester resins (* 1) to (* 4) are all polyester resins manufactured by Toyobo Co., Ltd. and have the property values shown in Table 3 below.

[0044]

[Table 3]

(* 5) Cymel 303: Mitsui Cytec Co., Ltd., low molecular weight methyl etherified melamine resin having a number average molecular weight of 1,000 or less, hexakis (methoxymethyl) melamine content of 60% by weight or more.

(* 6) Super Beckamine J-820-
60: n-butyl etherified melamine resin manufactured by Dainippon Ink and Chemicals, Inc.

(* 7) Organsol 2002 ES3: Nylon 12 fine particles having an average particle diameter of about 30 μm, manufactured by Ato Simie, France.

(* 8) ORGASOL 2002ES5: Nylon 12 fine particles with an average particle diameter of about 50 μm, manufactured by Ato Simie, France.

(* 9) TEXTURE5378: polypropylene fine particles having an average particle size of about 25 μm, manufactured by Shamrock Chemical.

(* 10) CAB-551-0.2: manufactured by Eastman Chemical Company, cellulose acetate butyrate, butyryl content 52%, acetyl content 2.0%, hydroxyl content 1.8%.

(* 11) CAB-53-11: Eastman Chemical Company, cellulose acetate butyrate,
Butyryl content 50%, acetyl content 2.8%, hydroxyl content 1.7%.

(* 12) Neutralized product of PTSA: A neutralized product of p-toluenesulfonic acid with di-n-butylamine. Neutralization equivalent of acid to amine is 1.0.

(* 13) Neutralized product of DDBSA: Neutralized product of dodecylbenzenesulfonic acid with dimethyloxazolidine. Neutralization equivalent of acid to amine is 1.0.

The tests in Table 2 were conducted according to the following test methods.

Test method Appearance of coated surface: Uniformity of irregularities on the coated surface (30 cm × 30 cm) was visually observed and evaluated according to the following criteria.

◎: Uneven unevenness and uniform reflected light ○: 1 to 4 places where reflected light differs from the surroundings △: 5 to 10 places same as above ×: Same place as above Ten or more places Bending workability: The test plate was bent 180 degrees in a room of 20 ° C. and 0 ° C. with the coated surface facing outward, and the T number at which cracks did not occur at the bent portion was displayed. The T number is 0T when a 180-degree bend is made without pinching anything inside the bent part, and 1T when a plate of the same thickness as the test plate is bent, and 2T. 2T for 1 sheet, 6 for 6 sheets
T.

Solvent resistance: JIS K-5400 8.
3.2 (1990) According to DuPont type impact resistance test,
An impact was applied to the coated surface of the coating plate under the conditions that the weight of the falling weight was 500 g, the tip diameter of the shooting core was 1/2 inch, and the height of the falling weight was 50 cm. Then attach cellophane adhesive tape to the shocked part,
The degree of peeling of the coating film when the tape was peeled off instantly was evaluated.

◯: No peeling is observed on the coated surface.

Δ: A slight peeling is recognized on the coated surface.

X: Significant peeling is recognized on the coated surface.

Adhesion: To reach the base material with a cutter knife on the surface of the coating film of the test plate, draw 11 parallel and 11 parallel straight lines at 1 mm intervals, and a 1 × 1 mm square 100
I made a piece. A cellophane adhesive tape was attached to this coated surface, and the coated surface after the tape was rapidly peeled off was observed and evaluated according to the following criteria.

◯: No peeling of the coating film is observed.

Δ: Peeled slightly, but 90 or more squares remained.

X: Peeled off a lot and the number of remaining cells was less than 90.

[0065] Blocking resistance: Two combined coating surfaces of the test plate, the temperature 50 ° C., 2 under the conditions of weighting 80 kg / cm ²
After being adhered for 4 hours, the plate was peeled off. The ease of peeling was evaluated.

⊚: The coated surfaces do not stick to each other and the plate can be easily removed.

◯: The coated surfaces are slightly adhered to each other, but the plate can be easily removed.

Δ: The coated surfaces stick to each other considerably and a force is required to peel off the plate, but no abnormality is recognized on the peeled coated surface.

X: The coated surfaces strongly adhere to each other, and when peeled off, an abnormality is recognized on the coated surfaces.

Solvent resistance: A coating of about 1 kg / cm ² was applied to the coated surface with a gauze impregnated with methyl ethyl ketone in a room at 20 ° C., and the material was reciprocated for a length of about 5 cm. The number of round trips until the primer coating (steel plate in case of one coat) was visible was recorded. When the primer coating film (steel plate in the case of one coat) was not visible after 50 reciprocations, 50 <was displayed.

Corrosion resistance: JIS Z-2371 salt spray test was evaluated by the area ratio of white rust generation on the flat surface after 500 hours.

[0072] ◎: White rust occurrence area ratio less than 1% ○: 1% or more and less than 10% △: 〃 10% or more and less than 30% ×: 〃 30% or more

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C09D 101/12 C09D 101/12 161/20 161/20 (56) Reference JP-A-4-366187 (JP, A) (58) ) Fields surveyed (Int.Cl. ⁷ , DB name) C09D 167/00 C09D 161/20 C09D 101/12 B05D 7/14 B05D 7/24

Claims (5)

(57) [Claims] 1. (A) Hydroxyl group-containing polyester resin 6
0 to 95 parts by weight and (B) amino resin curing agent 5 to 40
2 to 40 parts by weight of (C) organic polymer fine particles having an average particle diameter of 0.2 to 80 μm and (D) cellulose acetate butyrate 1 to 15 parts by weight based on 100 parts by weight in total.
A coating composition comprising a part by weight. 2. The polyester resin (A) has a number average molecular weight of 1,000 to 35,000 and a glass transition temperature of -25 to 25.
The coating composition according to claim 1, which is a polyester resin having a hydroxyl value of 3 to 100 mgKOH / g at 35 ° C. 3. The coating composition according to claim 1, wherein the amino resin curing agent (B) is a methyl etherified melamine resin or a mixed melamine resin of a methyl etherified melamine resin and a butyl etherified melamine resin. 4. A rust preventive pigment is further contained in an amount of 1 to 20 parts by weight based on 100 parts by weight of the total amount of the polyester resin (A) and the amino resin curing agent.
The coating composition according to any one of 1. 5. A primer coating on a metal plate,
Alternatively, a coated metal plate, on which a cured coating film of the coating composition according to claim 1 or 4 is formed without intervention.