JP3264053B2 - Powder coating composition giving a turtle pattern, coating method, coating film and coated product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder coating composition for giving a turtle pattern on the surface of a coating film, a coating method thereof, a coating film and a coated product.

[0002]

2. Description of the Related Art Powder coatings have been widely used in the field of application due to their advantages of no pollution and labor saving. In recent years, however, there has been a strong demand for the development of powder coatings having a design property on the coating film surface. As a method for imparting a design property to a coating surface of a powder coating, for example, Japanese Patent Application Laid-Open No. 60-168771 discloses a method of mixing a polyester resin-based powder coating composition and an acrylic resin-based powder coating composition. Disclosed are powder coating compositions for precoating that provide a textured coating.

Japanese Patent Application Laid-Open No. 63-91168 discloses that two kinds of powder paints containing a powdery silicon-based additive in one or both of them are used, and two coats and one bake are performed to obtain a hammer tone, a pearl tone, etc. A method for forming a special pattern coating film by using a powder coating is disclosed. Japanese Patent Application Laid-Open No. 1-288376 discloses a method for producing a coated metal plate having a concavo-convex pattern by mixing a thermoplastic resin with a thermosetting powder coating to obtain a concavo-convex pattern.

However, in any of the coating compositions,
Although a simple concavo-convex pattern can be formed, a coating film having a uniform, dense and excellent design with a turtle pattern could not be formed.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide a uniform, dense, three-dimensional appearance of a tortoiseshell pattern having excellent design properties, which is different from the conventional concavo-convex pattern, and is also excellent in coating film performance. And a powder coating composition.

Another object of the present invention is a method for coating the above powder coating composition, which is excellent in coating film performance and, unlike conventional concavo-convex patterns, is uniform, dense and has a three-dimensional appearance. An object of the present invention is to propose a simple coating method for forming a turtle pattern having a design property.

Another object of the present invention is to provide a coating film formed from the above powder coating composition, which is excellent in coating film performance and, unlike conventional concavo-convex patterns, is uniform, dense, and three-dimensional. An object of the present invention is to provide a turtle-patterned coating film having excellent design properties.

Still another object of the present invention is a coated article having a coating film formed from the above powder coating composition, which is excellent in coating film performance and, unlike the conventional uneven pattern, is uniform and dense. Accordingly, it is an object of the present invention to provide a painted article on which a turtle pattern having an excellent design with a three-dimensional effect is formed.

[0009]

SUMMARY OF THE INVENTION The present invention provides the following powder coating composition, a coating method thereof, a coating film and a coated product. (1) (A) 60 to 95 parts by weight of a resin for powder coating which has a hydroxyl value of 10 to 320 mgKOH / g and is solid at ordinary temperature;
(C) A secondary or tertiary amino group having a boiling point of 80 to 250 ° C is added to 100 parts by weight of a mixture of 5 to 40 parts by weight of a toluenesulfonamide-modified melamine resin having a glass transition temperature of 30 to 70 ° C. A sulfonic acid compound blocked with an amine compound having
A powder coating composition which gives a turtle pattern characterized by containing by weight. (2) After applying the powder coating composition according to (1) above on a substrate, baking at a temperature of 150 to 300 ° C. for 20 seconds to 60 minutes to form a coating film having a thickness of 20 to 200 μm. The coating method of the powder coating composition according to the above (1), which is characterized in that: (3) The powder coating composition described in (1) above is applied on a substrate and baked at a temperature of 150 to 300 ° C. for 20 seconds to 60 minutes, and has a thickness of 20 to 200 μm. A coating film formed from the powder coating composition according to the above (1). (4) After coating the powder coating composition according to (1) above on a substrate, it has a coating film having a thickness of 20 to 200 μm formed by baking at a temperature of 150 to 300 ° C. for 20 seconds to 60 minutes. A coated article having a coating film formed from the powder coating composition according to the above (1).

The normal temperature solid resin powder containing a hydroxyl group (A) used in the present invention is a normal temperature solid resin used for powder coating and has a hydroxyl value of 10 to 32.
0 mgKOH / g, preferably 25-300 mgKOH
/ G and a glass transition temperature (Tg) of 30 to 120 ° C, preferably 35 to 100 ° C. As the component (A), for example, an acrylic resin containing a hydroxyl group, a polyester resin, a fluororesin and the like can be mentioned.

As an acrylic resin for powder coating, for example, Almatex PD-800 manufactured by Mitsui Toatsu Chemicals, Inc.
0, PD-8100 and S.D. C. JONCRYL J-587, J-800, SCX manufactured by Johnson
-802 (all are trade names).

Examples of the polyester resin for powder coating include ER-6620 and ER-6 manufactured by Nippon Ester Co., Ltd.
640, XI-6021, XI-7909, XI-70
19. Faindex M-8000, M-8070 and M-8076 manufactured by Dainippon Ink and Chemicals, Inc., Upikacoat GV-110 and GV manufactured by Upika Japan Co., Ltd.
-150, GV-741, Hitachi Chemical Co., Ltd. P
C Resin 2H, 3H, URALAC P manufactured by DSM
-4215, 30-3000, 3 manufactured by CARGILL
0-3002, 30-3011, 30-3012, 30
-3020, UCB Crylcot 2383, 2392, 3145, Bayer Crelan
U-502, Alfalat manufactured by Hoechst
AN-739, AN-759, VAN9969
(Both are trade names).

Examples of the fluororesin for powder coating include Lumiflon LF-710 (trade name) manufactured by Asahi Glass Co., Ltd. These components (A) can be used alone or in combination of two or more.

The toluenesulfonamide-modified melamine resin (B) used in the present invention is a condensate of melamine-formaldehyde condensate ether (MF) and toluenesulfonamide (TS), and has a glass transition temperature (Tg).
However, those having a temperature of 30 to 70C, preferably 35 to 50C are used.

The above-mentioned toluenesulfonamide-modified melamine resin includes a non-crosslinked condensate oligomer in which 1 mol of MF and 1 to 4 mol of TS are condensed, and the condensate oligomer having --CH ₂ -or --CH ₂ Crosslinked oligomers crosslinked by OCH ₂ — groups are included. The number average molecular weight (Mn) of the toluene sulfonamide-modified melamine resin composed of such an oligomer mixture is from 600 to 2,000, preferably from 700 to 1600, and the molecular weight distribution (Mw / Mn).
Is 1 to 7, preferably 2 to 6, functional group equivalent to RO- 130 to 200 g / equivalent, preferably 150 to 18
A suitable amount is 0 g / equivalent and the amount of the functional group contained in one molecule of the oligomer is 4 to 10, preferably 5 to 8.

The basic reaction formula for producing a toluenesulfonamide-modified melamine resin (TS-MF) from MF and TS is shown in equation [1].

[0017]

Embedded image (In the formula, R represents an alkyl group, at least three of the six are methyl groups, and the rest are alkyl groups having 2 to 4 carbon atoms.)

Examples of the toluenesulfonamide-modified melamine resins, preferably those using hexamethoxymethylmelamine to MF, and in particular Progress Organic Coating, 20
(1992) Resins M-1, M-2 described in pp 301 to 323,
M-3 is preferred.

The boiling point of component (C) used in the present invention is from 80 to 2
A sulfonic acid compound blocked with an amine compound having a secondary or tertiary amino group at 50 ° C. (hereinafter sometimes referred to as a blocked acid catalyst) is used as a curing catalyst and includes, for example, p-toluenesulfonic acid, dodecyl Aromatic sulfonic acids such as benzenesulfonic acid, dinonylnaphthalenesulfonic acid, and dinonylnaphthalenedisulfonic acid, and the following structural formulas [2] to

One or two or more of the aliphatic sulfonic acids represented by [9] are used with a boiling point of 80 to 25.
Blocked with an amine compound having a secondary or tertiary amino group at 0 ° C.

[0020]

Embedded image (In the formula, R ¹ represents an alkyl group having 1 to 22 carbon atoms, R ² represents an alkyl group having 4 to 8 carbon atoms, and R ³ represents an alkyl group having 13 to 17 carbon atoms.)

The use of an aliphatic sulfonic acid is preferable because it has excellent compatibility with a resin as compared with an aromatic sulfonic acid, and thus has a low risk of being crystallized in a coating material and causing irregularities in a coating film. Aliphatic sulfonic acid is obtained by converting sodium sulfonate or potassium salt of aliphatic sulfonic acid, which is generally used as a surfactant, into sodium salt or potassium salt to convert it to a free acid. Can be.

Here, examples of the aliphatic sulfonic acid salt as a starting material include those represented by the following structural formulas [10] to [17].

[0023]

Embedded image (In the formula, R ⁴ represents an alkyl group having 1 to 22 carbon atoms, R ⁵ represents an alkyl group having 4 to 8 carbon atoms, and R ⁶ represents an alkyl group having 13 to 17 carbon atoms.)

These aliphatic sulfonic acid salts can be converted to the free acid by desodiumization or depotassiumization with an inorganic acid. Aliphatic sulfonic acid salts having less than 4 carbon atoms have difficulty in compatibility with resins like aromatic sulfonic acids, and therefore those having 4 or more carbon atoms are preferred.

Examples of the inorganic acid include ordinary sulfuric acid, hydrochloric acid,
Nitric acid, phosphoric acid, or the like can be used. At this time, the amount of the inorganic acid used is not limited, but later coating film performance,
In particular, in order not to impair the water resistance, the amount is preferably in the range of 0.5 to 1.5 times equivalent to the aliphatic sulfonate.

If the amount is less than 0.5 equivalents, unreacted aliphatic sulfonate remains, and if it exceeds 1.5 equivalents, the aliphatic sulfonate is not treated with sodium or potassium. In any case, the water resistance of the coating film is lowered, which is not preferable. The conditions for sodium removal or potassium removal can be quantitatively determined at room temperature according to a conventional method.

Other examples of the acid catalyst include organic carboxylic acids such as maleic acid and phthalic acid, carboxylic acids contained in polyols, and phosphate catalysts. In combination with the toluenesulfonamide-modified melamine resin, the effect of promoting the cross-linking reaction for forming a turtle pattern is weak. Also, the use of unblocked sulfonic acid does not provide a turtle pattern.

Examples of the amine compound having a boiling point of 80 to 250 ° C. and having a secondary amino group serving as a blocking agent include di-2-ethylhexylamine, disecondary butylamine, diallylamine, N-methylhexylamine, and
-Pipecoline, 4-pipecholine, 2,4-lupetidine,
2,6-lupetidine, 3,5-lupetidine, morpholine, N-methylbenzylamine; amine compounds having a tertiary amino group include, for example, N-methylmorpholine,
Triethylamine, tributylamine, N, N-dimethylallylamine, N-methyldiallylamine, triallylamine, N, N, N ', N'-tetramethyl-1,2
-Diaminoethane, N, N, N ', N'-tetramethyl-1,3-diaminopropane, N, N, N', N'-tetraallyl-1,4-diaminobutane, N-methylpiperidine, pyridine, 4-ethylpyridine, tripropylamine, N-propylpyridylallylamine, 3-dimethylaminopropanol, 2-ethylpyrazine, 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,4-lutidine, 2,5- Lutidine, 3,4-lutidine, 3,5
-Lutidine, 2,4,6-collidine, 2-methyl-4-
Ethylpyridine, 2-methyl-5-ethylpyridine,
N, N, N ', N'-tetramethylhexamethylenediamine, N-ethyl-3-hydroxypiperidine, 3-methyl-4-ethylpyridine, 3-ethyl-4-methylpyridine, 4- (5-nonyl) Pyridine; amine compounds having secondary and tertiary amino groups include, for example, imidazole and N-methylpiperazine;
A mixture of two or more species is used.

When the boiling point of the blocking agent is less than 80 ° C., the dissociation of the blocking agent is too fast, so that the coating film foams and a three-dimensional turtle pattern cannot be obtained. Is too slow to release a turtle pattern.

The preparation of the blocked sulfonic acid compound is carried out by
An amine compound having a tertiary or tertiary amino group and a sulfonic acid are charged in a container and stirred at 20 to 30 ° C. for 10 to 20 minutes.

The mixing ratio of the amine compound / sulfonic acid is 0.5 to 2, preferably 0.8 to 1.5, in a molar ratio, and only in this case, a beautiful three-dimensional turtle pattern is formed. . When the molar ratio of the amine compound / sulfonic acid is less than 0.5, there are many sulfonic acids which are not blocked, so that the curing reaction proceeds from a low temperature at the time of baking, and a three-dimensional turtle pattern is not formed. When the ratio exceeds 2, no improvement is observed by the addition of the blocking agent, and the corrosion resistance of the obtained coating film decreases.

The mixing ratio of each component is as follows.
For 100 parts by weight of a mixture of 5 parts by weight, preferably 65 to 94 parts by weight, and 5 to 40 parts by weight, preferably 6 to 35 parts by weight of the component (B), the component (C) is 0.1% as sulfonic acid. It is 1 to 3 parts by weight, preferably 0.2 to 2 parts by weight.

When the amount of the component (A) is less than 60 parts by weight, the coating film is brittle, and it is difficult to obtain a three-dimensional effect due to fluctuations in the baking conditions. Is not performed, and it is difficult to form a tortoiseshell pattern having a three-dimensional effect.

When the amount of the component (B) is less than 5 parts by weight, sufficient crosslinking is not carried out, and a three-dimensional turtle pattern is unlikely to be generated. When the amount exceeds 40 parts by weight, the coating film is brittle and the baking conditions are insufficient. This makes it difficult to obtain a three-dimensional tortoiseshell pattern.

When the amount of the component (C) is less than 0.1 part by weight, the catalytic effect at the time of baking is insufficient, so that a three-dimensional tortoiseshell pattern is not formed. On the other hand, when the amount exceeds 3 parts by weight, the reaction is too fast to cause cracks, and there is no three-dimensional effect, and sufficient corrosion resistance cannot be obtained.

The powder coating composition of the present invention contains (A)
In addition to the essential components of (C), coloring pigments such as inorganic pigments such as titanium dioxide, red iron oxide, yellow iron oxide and carbon black, phthalocyanine blue, phthalocyanine green, quinacridone red pigment, and isoindolinone yellow pigment; Organic pigments; metal powders such as aluminum powder and copper powder; talc, barium sulfate, silica, calcium carbonate,
Extenders such as alumina white and clay; mica powder and the like may be added. In both cases of the clear powder coating and the colored powder coating, a thermoplastic resin containing no hydroxyl group, such as a fluororesin, a vinyl copolymer resin, a polyethylene resin, a polypropylene resin, and a polyester resin can be added.

These pigments, metal powders, thermoplastic resins and the like are used in an amount of 40 parts by weight per 100 parts by weight of the powder coating composition of the present invention.
It is preferably less than part by weight, and can be used as a pattern adjuster for adjusting the size of the pattern of the turtle pattern. If the amount used exceeds 40 parts by weight, the corrosion resistance of the coating film is reduced.

In addition, additives such as a leveling agent, a pigment dispersant, an ultraviolet absorber, a light stabilizer, a heat stabilizer, and an antifoaming agent may be added to the powder coating composition of the present invention as required. Can also. Also, add silicone resin additives,
By intentionally repelling the coating film, a hammer tone tone and a turtle pattern can be imparted.

Usually, the powder coating mainly uses an electrostatic spraying method. Therefore, from the viewpoint of the coating workability (coating efficiency and throwing power), the particle diameter of the powder coating composition of the present invention is 15%.
Desirably, the mesh size is 0 mesh or less.

As the substrate on which the powder coating composition of the present invention is coated, any substrate can be used as long as it can withstand the baking conditions described below. A metal plate such as a steel plate, an aluminum plate, and a stainless steel plate is preferable.

To apply the powder coating composition of the present invention,
A commercially available electrostatic coating machine (loading voltage -50)
~ -90 kV) or evenly by powder coating, etc., then 150 ~ in hot air baking furnace, infrared furnace, induction heating furnace, etc.
300 ° C, preferably at 160 to 250 ° C for 20 seconds to 60
For 20 minutes, preferably 30 seconds to 30 minutes.
The coating thickness is set to 00 μm, preferably 30 to 100 μm. By coating in this manner, a turtle-patterned coating film having excellent coating performance such as corrosion resistance and excellent three-dimensional appearance is formed.

The baking conditions are determined within the above range depending on the base material (substrate) to be used. For example, when a 0.5 mm thick iron plate is used, baking may be performed at 160 to 180 ° C. for 15 to 20 minutes. . When the coating thickness of the powder coating is less than 20 μm, a sufficient three-dimensional turtle pattern cannot be obtained.
If it exceeds m, a foaming phenomenon of the coating film occurs, and a beautiful turtle pattern cannot be obtained.

The coating film formed by baking the powder coating composition of the present invention has two-dimensional irregular (fine) irregularities in a crepe pattern, It varies depending on the composition of the paint, the coating conditions, the baking conditions, and the like. By preparing these, a coating film having an arbitrary turtle pattern can be obtained.

FIG. 1 is a schematic plan view schematically showing a coated article formed from the powder coating composition of the present invention, and FIG. 2 is a schematic sectional view thereof.

In the figure, reference numeral 10 denotes a coating material, on which a coating film 2 is formed on a substrate 1. In the coating film 2, a high and tortoise-shaped irregular network pattern 3 is formed almost uniformly on the entire surface of the coating film 2, and furthermore, a crepe-shaped dense unevenness 4 is formed on the inside of the coating film 2 in an unspecified direction. It is formed almost uniformly, is uniform and dense as a whole, and has a three-dimensional appearance and has an excellent design.

A coated article having a coating film on which such a turtle pattern is formed has excellent design properties and is also excellent in coating properties such as corrosion resistance. Household appliances such as washing machines and air conditioners; Road materials such as poles, soundproof walls, and guardrails; Building materials such as inner and outer walls, pillars, roofs, and partition boards of buildings;
Telecommunications equipment; metal products such as iron, galvanized steel, stainless steel, aluminum, etc. such as pipes, fittings, metal machinery, garbage cans, glove compartments, steel furniture, steel desks, and beverage cans;
It can be used in the fields of glass, wood, gypsum board, woven fabric made of glass fiber or the like as a raw material, heat-resistant paper, plastics having a heat resistance of 150 ° C. or more, and printed or colored materials thereof.

Although the mechanism of the formation of the turtle pattern has not been fully elucidated, when the uncured coating film reaches a certain baking condition, rapid surface hardening progresses, so that the surface layer is distorted and corrected. Therefore, it is considered that a turtle pattern appears on the surface layer. In the present invention, in the presence of a sulfonic acid compound (blocked acid catalyst) blocked with a specific amine compound, a large amount of an alkoxy group (methoxy group) having high reactivity with a hydroxyl group of the resin (A) for powder coating materials is contained. It is presumed that by blending the toluenesulfonamide-modified melamine resin described above, such a rapid surface hardening at the time of baking produces a turtle pattern.

[0048]

As described above, according to the present invention, a specific toluenesulfonamide-modified melamine resin and a melamine resin having a boiling point of 8.
Since a sulfonic acid compound blocked with an amine compound having a secondary or tertiary amino group at 0 to 250 ° C. is blended at a specific ratio, unlike a conventional uneven pattern,
A powder coating composition which is uniform, dense, has a three-dimensional appearance, has a turtle pattern having excellent design properties, and is excellent in coating film performance can be obtained.

According to the present invention, the powder coating composition can be easily applied.

Further, according to the present invention, a coating film formed from the above powder coating composition is excellent in coating film performance, and is uniform and dense, and has a three-dimensional appearance unlike conventional concavo-convex patterns. A turtle-patterned coating film having a certain excellent design property can be obtained, and a coated article having such a coating film can be obtained.

[0051]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In each example, parts are parts by weight and% is% by weight.
Is shown. Example 1 Based on the composition shown in Table 1, Mitsui Toatsu Chemicals Co., Ltd. Armatex PD-8000 (trade name, solid content 100%) 7
5 parts, 25 parts of a toluenesulfonamide-modified melamine resin M-1 (trade name, 100% solid content) manufactured by Monsanto Chemical Co., and tripropylamine as a sulfonic acid blocked with a tertiary amine having a boiling point of 80 to 250 ° C. Blocked paratoluenesulfonic acid 2.0
And then uniformly mixed for about 1 minute by a drive render (trade name: Henschel mixer manufactured by Mitsui Miike Kakoki Co., Ltd.), and then extruded and kneaded at a temperature of 80 to 100 ° C. (Bus Co., Ltd.). Product name Buscon Kneader PR-46)
The mixture was melt-kneaded using, and after cooling, was finely pulverized with a hammer impact pulverizer. Next, the mixture was filtered through a 150-mesh wire net to obtain a powder coating.

The obtained powder coating is 0.5 mm × 100 m
Electrostatic coating is performed on an iron plate having a zinc phosphate treatment of mx 200 mm and baked at 170 ° C for 20 minutes to obtain a coating thickness of 50 mm.
A μm coated plate was obtained. A turtle pattern as shown in FIG. 1 was formed on the painted plate. Table 1 shows the appearance of the obtained coated plate and the performance of the cured coating film.

Examples 2 to 10, Comparative Examples 1 to 4 Based on the formulations of Examples 2 to 10 and Comparative Examples 1 to 4 in Tables 1 and 2, Powder coatings of Comparative Examples 1 to 4 were obtained. Examples 2-1 obtained
0, the powder coatings of Comparative Examples 1 to 4 were applied on a 0.5 mm × 100 mm × 200 mm zinc phosphate-treated iron plate in the same manner as in Example 1; Examples 1 to 4 are at 170 ° C for 20 minutes, and Examples 3 to 5 are 180 ° C.
For 20 minutes to obtain a coated plate having a coating thickness of 50 μm. Tables 1 and 2 show the appearance of each coated plate and the performance of the cured coating film.

In Table 1, Examples 1 and 2 are examples in which the type of the acrylic resin for powder coating containing a hydroxyl group (A) and the ratio to the toluenesulfonamide-modified melamine resin (B) are changed. And Examples 3 to 9 are (A)
Example 10 is an example in which the type of the polyester resin for a powder coating containing a hydroxyl group as the component, the ratio, the type, and the pattern modifier of the toluenesulfonamide-modified melamine resin as the component (B) are changed. This is an example in which a fluororesin is used as a resin for a powder coating containing a hydroxyl group.

[0055]

[Table 1]

[0056]

[Table 2]

Footnotes to Tables 1 and 2 1) Mitsui Toatsu Chemicals, Inc., trade name, acrylic resin, hydroxyl value = 87 mgKOH / g, solid content = 100%, Tg
= 65 ° C 2) S.P. C. Manufactured by Johnson Corporation, trade name, acrylic resin, hydroxyl value = 94 mgKOH / g, solid content = 100
%, Tg = 50 ° C. 3) Nippon Ester Co., Ltd., trade name, polyester resin, hydroxyl value = 29 mg KOH / g, solid content = 100
%, Tg = 63 ° C. 4) CARGILL, trade name, polyester resin,
Hydroxyl value = 295 mg KOH / g, solid content = 100%,
Tg = 44 ° C. 5) Hitachi Chemical Co., Ltd., trade name, polyester resin, hydroxyl value = 100 mgKOH / g, solid content = 100
%, Tg = 58 ° C. 6) Asahi Glass Co., Ltd., trade name, fluororesin, hydroxyl value =
52 mgKOH / g, solid content = 100%, Tg = 60 ° C. 7) Monsanto Chemical Co., trade name, toluenesulfonamide-modified melamine resin, Mn =
1340, Mw / Mn = 5.7, equivalent = 180 g / e
q, solid content = 100%, Tg = 42.3 ° C. 8) Monsanto Chemical Co., trade name, toluenesulfonamide-modified melamine resin, Mn =
1023, Mw / Mn = 2.5, equivalent = 158 g / e
q, solid content = 100%, Tg = 40.4 ° C. 9) Monsanto Chemical Co., trade name, toluenesulfonamide-modified melamine resin, Mn =
896, Mw / Mn = 2.0, equivalent weight = 151 g / eq,
Solid content = 100%, Tg = 36.8 ° C. 10) paratoluenesulfonic acid blocked with tripropylamine, tripropylamine / paratoluenesulfonic acid = 1/1 (molar ratio), tripropylamine boiling point = 1
56.5 ° C. 11) Hosterflon 9205 (trademark), manufactured by Hoechst Co., Ltd., tetrafluorocarbon 12) Parts by weight based on 100 parts by weight of resin and curing agent 13) Visual judgment Good: A turtle pattern was formed on the entire surface. Did not occur at all. 14) Visual judgment Good: There is a three-dimensional effect Poor: There is no three-dimensional effect 15) According to JIS K-5400 (1990) 9.1 salt water spray resistance. Good: No rust or swelling on the coating film Bad: Rust or swelling on the coating film

As is evident from Tables 1 and 2, Examples 1 to 10 provide good turtle pattern and three-dimensional appearance and are excellent in corrosion resistance, whereas the amount of toluene sulfonamide-modified melamine resin is less than 5. Comparative Example 1 and Comparative Example 2 in which the amount of the toluenesulfonamide-modified melamine resin exceeds 40 parts by weight did not give a crevices pattern and a three-dimensional appearance, and had poor corrosion resistance. In Comparative Example 3 in which the amount of the blocked acid catalyst was less than 0.1 part by weight, a three-dimensional effect was not obtained with a turtle pattern, and in Comparative Example 4 in which the amount of the blocked acid catalyst exceeded 3 parts by weight, no three-dimensional effect was obtained. Moreover, the corrosion resistance was poor.

[Brief description of the drawings]

FIG. 1 is a schematic plan view schematically showing a coated article formed from the powder coating composition of the present invention.

FIG. 2 is a schematic sectional view of the painted object of FIG.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 base material 2 coating film 3 irregular network pattern 4 dense unevenness 10 painted object

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-219881 (JP, A) JP-A-1-254776 (JP, A) JP-A-62-205173 (JP, A) JP-A-62-205173 174276 (JP, A) JP-A-3-86771 (JP, A) JP-A-52-28594 (JP, A) JP-A-2-145662 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 5/03 C09D 5/28 C09D 101/00-201/10

Claims (4)

(57) [Claims] (A) a hydroxyl value of 10 to 320 mg KO
100 parts by weight of a mixture consisting of 60 to 95 parts by weight of a resin for powder coating which is solid at room temperature of H / g and (B) 5 to 40 parts by weight of a toluenesulfonamide-modified melamine resin having a glass transition temperature of 30 to 70 ° C. (C) 0.1 to 3 parts by weight of a sulfonic acid compound blocked with an amine compound having a secondary or tertiary amino group having a boiling point of 80 to 250 ° C. as a sulfonic acid, and Give powder coating composition. 2. After applying the powder coating composition according to claim 1 on a substrate, the composition is heated at a temperature of 150 to 300 ° C. for 20 seconds to 60 seconds.
The method for coating a powder coating composition according to claim 1, wherein the coating is formed by baking for 20 minutes to form a coating film having a thickness of 20 to 200 µm. 3. After the powder coating composition according to claim 1 is applied on a substrate, the composition is heated at a temperature of 150 to 300 ° C. for 20 seconds to 60 hours.
The coating film formed from the powder coating composition according to claim 1, wherein the coating film is formed by baking for 20 minutes and has a thickness of 20 to 200 µm. 4. After applying the powder coating composition according to claim 1 on a substrate, the composition is heated at a temperature of 150 to 300 ° C. for 20 seconds to 60 hours.
A coated article having a coating film formed from the powder coating composition according to claim 1, having a coating film having a thickness of 20 to 200 µm formed by baking for minutes.