JP2003105265A - Power coating material and method for forming coated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a powder coating material excellent in storage stability, excellent especially in weatherability of the coated film, and excellent in workability at the application and finished appearance as well, and to provide a method for forming the coated film. SOLUTION: This powder coating material is obtained by spray drying an organic solvent solution comprising (A) an organopolysiloxane having a curable reactive group, (B) a thermosetting resin, (C) a curing agent reactive with the thermosetting resin (B), and (D) an organic solvent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a new and useful powder coating material and a method for forming a coating film. More specifically, an organopolysiloxane (A) having a curing reactive group, a thermosetting resin (B) and a thermosetting resin (B).
A powder coating obtained by spray-drying an organic solvent solution containing a curing agent (C) capable of reacting with an organic solvent (D), the coating having particularly excellent weather resistance. And a powder coating method capable of providing a coating film excellent in storage stability, fluidity, workability of electrostatic coating, and finished appearance of the coating film, and a method for forming a coating film using the powder coating material.

[0002]

2. Description of the Related Art Powder coatings are widely used for metal coatings in general as environmentally friendly coatings that do not volatilize organic solvents into the atmosphere during coating, especially on roads such as gates, fences and guardrails. The use for outdoor applications such as materials is increasing.

On the other hand, some powder coatings having excellent weather resistance have been proposed. For example, patent 1973
The powder coating using a fluorine-containing copolymer as disclosed in Japanese Patent No. 174 has a feature that it is very excellent in weather resistance.

However, the powder coatings using these fluorine-containing copolymers are very expensive, and therefore their applications are very limited. On the other hand, attempts have been made to improve the weather resistance of coating films by adding a specific silicon compound. (JP-A-08-113696, JP-A-08-143790, JP-A-10-
These silicon compounds have low affinity with other raw materials, and even if they are simply dry-blended and used, they cause cissing and the like in the coating film and cause abnormal coating film. In addition, it is difficult to completely mix the silicon compound with other raw materials even by the manufacturing method by melt-kneading which is usually performed as a manufacturing method of powder coating, and the localization of the silicon compound on the surface of the coating film is difficult. It easily occurs and the effect of improving weather resistance is not sufficient.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made extensive studies to solve the above-mentioned various problems in the prior art and to obtain a highly practical powder coating material and coating film forming method. The problems to be solved by the present invention are excellent in storage stability, particularly excellent in weather resistance of a coating film, workability at the time of coating, a powder coating material excellent in finished appearance of the coating film and a coating film forming method thereof. To provide.

[0006]

Means for Solving the Problems The inventors of the present invention have earnestly studied to solve the above-mentioned problems, and as a result, as a result, an organopolysiloxane (A) having a curing reactive group and a thermosetting resin ( B) and a thermosetting resin (B), a curing agent (C), and a powder coating obtained by spray-drying an organic solvent solution containing an organic solvent (D), or an organopolysiloxane ( A), a thermosetting resin (B) or a curing agent (C), and a powder mixture obtained by spray-drying an organic solvent solution containing an organic solvent (D), as an essential component. The powder coating to be obtained is excellent in storage stability, and a coating film formed using the powder coating is found to be particularly excellent in weather resistance and storage stability, and also to be excellent in the appearance of the coating film. The present invention has been completed here.

That is, according to the present invention, an organopolysiloxane (A) having a curing reactive group, a thermosetting resin (B),
The present invention provides a powder coating material obtained by spray-drying a curing agent (C) capable of reacting with a thermosetting resin (B) and an organic solvent solution containing an organic solvent (D).

The present invention also provides an organic solvent solution containing an organopolysiloxane (A) having a curing reactive group, a thermosetting resin (B) or a curing agent (C), and an organic solvent (D). To provide a powder coating material obtained by using a powder mixture of an organopolysiloxane (A) and a thermosetting resin (B) or a curing agent (C) as an essential component, obtained by spray drying. Is.

The present invention further provides a method for forming a coating film, which comprises using the above powder coating material in a method for forming a coating film of a single layer or a plurality of layers on an object to be coated, A coated article having a coating film formed by the coating film forming method is also provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be specifically described below. The powder coating material of the present invention comprises an organopolysiloxane (A) having a curing reactive group, a thermosetting resin (B) and a curing agent (C) capable of reacting with the thermosetting resin (B), and an organic solvent. It is obtained by spray-drying an organic solvent solution containing (D). Further, the powder coating composition of the present invention may alternatively contain an organopolysiloxane (A),
It is also obtained by using a powder mixture obtained by spray-drying an organic solvent solution containing a thermosetting resin (B) or a curing agent (C) and an organic solvent (D) as an essential component. .

First, the organopolysiloxane (A) will be described. The organopolysiloxane (A) used in the present invention has a curing reactive group capable of reacting with the curing reactive group of the thermosetting resin (B) or the curing agent (C) or a self-curing reactive group. Those that have are used. By using the organopolysiloxane (A),
The weather resistance and mechanical properties of the coating film are improved.

The organopolysiloxane (A) used in the present invention is preferably branched, from the viewpoint that the effect of improving the weather resistance and mechanical properties of the coating film can be exhibited more effectively, but its structure is Is not particularly limited. Here, the branched organopolysiloxane means a trifunctional siloxane unit and // in its molecular structure.
Alternatively, it is an organopolysiloxane containing a tetrafunctional siloxane unit as an essential constituent unit, and examples of other optional siloxane units include a monosensitive siloxane unit and a difunctional siloxane unit.

Typical examples of the organopolysiloxane (A) include, for example, general formula (I): (R ₁ SiO _3/2 ) _a (R ₂ SiO _2/2 ) _b (SiO _4/2 ) _c (I) (R independently represents a hydrocarbon group or a curing reactive group, and the amount of the curing reactive group relative to the total amount of R in the organopolysiloxane is 0.1 to 70 mol%.
Is a positive number, b is 0 or a positive number, and c is 0 or a positive number. ) Organopolysiloxane represented by

General Formula (II): (R ₃ SiO _1/2 ) _d (R ₂ SiO _2/2 ) _e (SiO _4/2 ) _f (II) (R is a hydrocarbon group or a curing reaction The amount of the curing reactive group is 0.1 to 70 mol% with respect to the total amount of R in the organopolysiloxane.
Is a positive number, e is 0 or a positive number, and f is a positive number. ) Organopolysiloxane represented by

[0015]   General formula (III): (R_ThreeSiO_1/2)_g(R_TwoSiO_2/2)_h(RSiO_3/2)_i(SiO _4/2 )_j    (III) (R independently represents a hydrocarbon group or a curing reactive group.
The total amount of R in the organopolysiloxane is
The amount of the chemically reactive group is 0.1 to 70 mol%. Also g
Is a positive number, h is a positive number, i is a positive number, and j is
It is 0 or a positive number. ) Organopolysiloxa
Can be given.

Examples of the curing-reactive group of the organopolysiloxane (A) include a hydroxyl group, a silanol group, an epoxy group, an alkoxy group and a carboxyl group, but the storage stability of the powder coating and the coating film. Of these, a hydroxyl group, a silanol group, an epoxy group, and an alkoxy group are preferable because of their excellent mechanical properties and finished appearance.

Examples of typical hydroxyl groups include methylol group, ethylol group and butyrol group.

Typical examples of the epoxy group are 2,3-epoxypropyl group, 3,4-epoxybutyl group, 2-methyl-2,3-epoxypropyl group and 4,5-epoxypentyl group. Group, 2-glycidoxyethyl group, 3-glycidoxypropyl group, 4-glycidoxybutyl group, 2- (3,4-epoxycyclohexyl)
Examples thereof include an ethyl group, 3- (3,4-epoxycyclohexyl) propyl group, 4- (3,4-epoxycyclohexyl) butyl group and the like.

On the other hand, typical examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group and a butoxy group.

The content of the curing reactive group in the organopolysiloxane (A) is preferably 0.1 to 70 mol%. When the content of the curing reactive group in the organopolysiloxane (A) is within the above range, a coating film having excellent weather resistance and mechanical properties can be obtained.

Typical hydrocarbon groups of the organopolysiloxane (A) are methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group,
Alkyl group such as heptyl group; vinyl group, allyl group,
Alkenyl groups such as butenyl group, pentenyl group, hexenyl group; aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl groups such as benzyl group, phenethyl group; chloromethyl group, 3-chloropropyl group, Substituted alkyl groups such as a 3,3,3-trifluoropropyl group and a nonafluorobutylethyl group can be mentioned.
Among these, a methyl group and a phenyl group are preferable because of excellent weather resistance and mechanical properties of the coating film.

Particularly, when the content of the phenyl group in the organopolysiloxane (A) is in the range of 30 to 99 mol%, the affinity with the thermosetting resin (B) is improved and the coating film Mechanical properties are further improved.

The amount of the organopolysiloxane (A) added is based on the weight of the thermosetting resin (B) from the viewpoint that the effect of improving the weather resistance of the resulting coating film is sufficiently exhibited.
2 to 100% by weight is preferable, and 5 to 50% by weight is more preferable.

Next, the thermosetting resin (B) will be described. The type of resin used as the thermosetting resin (B) used in the present invention is not particularly limited, and any resin used for powder coating can be used. Examples of such resins include acrylic resins, polyester resins, epoxy resins, urethane resins, fluororesins, and the like. Among these, acrylic resins, polyester resins, and fluororesins are particularly preferable because of their excellent coating film appearance.

First, in the case where the thermosetting resin (B) is a thermosetting acrylic resin, a known and commonly used method can be applied to prepare the thermosetting acrylic resin, but it has a curing reactive group. The simplest method is to radically polymerize vinyl monomers, if necessary, with other copolymerizable vinyl monomers, in an organic solvent. Recommended. As the radical polymerization initiator and the organic solvent used at that time, known and conventional ones can be used as they are.

Examples of the curing reactive group of the thermosetting acrylic resin include an epoxy group, a carboxyl group, a hydroxyl group, an amide group, an amino group, an acid anhydride group and a (block) isocyanate group, but they are easy to produce. Therefore, at least one selected from the group consisting of epoxy groups, carboxyl groups and hydroxyl groups is desirable. Above all, it is more preferable that at least one of the curing reactive groups is an epoxy group because of excellent storage stability and appearance of the coating film.

If only typical examples of the vinyl monomers having a curing reactive group are given, first, when the curing reactive group is an epoxy group, for example, glycidyl (meth) acrylate, Various epoxy group-containing monomers such as β-methylglycidyl (meth) acrylate, glycidyl vinyl ether and allyl glycidyl ether; (2-oxo-1,3-oxolane) methyl (meth) acrylate, (2- Oxo-1,3-
Oxolane) group-containing vinyl monomers; 3,4-epoxycyclohexyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4
There are various alicyclic epoxy group-containing vinyl monomers such as epoxycyclohexylethyl (meth) acrylate.

When the curing reactive group is a carboxyl group, various carboxyl group-containing monomers such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid; monomethyl fumarate; Monoethyl fumarate, monobutyl fumarate, monoisobutyl fumarate,
Monotert-butyl fumarate, monohexyl fumarate, monooctyl fumarate, mono-2-ethylhexyl fumarate, monomethyl maleate, monoethyl maleate, monobutyl maleate, monoisobutyl maleate, monotert-butyl maleate, monohexyl maleate. , Monooctyl maleate, mono 2 maleate
-Monoesters of various α, β-unsaturated dicarboxylic acids such as ethylhexyl and monohydric alcohols having 1 to 18 carbon atoms; monomethyl itaconate, monoethyl itaconate, monobutyl itaconate, monoisobutyl itaconate, There are monoalkyl esters of itaconic acid, such as monohexyl itaconic acid, monooctyl itaconic acid and mono-2-ethylhexyl itaconic acid.

When the curing-reactive group is a hydroxyl group, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate. , 3-hydroxybutyl (meth)
Various hydroxyl group-containing (meth) acrylates such as acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate;
Addition reaction products of various (meth) acrylates and ε-caprolactone as listed above;

2-hydroxyethyl vinyl ether, 3
-Hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 3-hydroxybutyl vinyl ether, 2-
Hydroxy-2-methylpropyl vinyl ether, 5-
Various hydroxyl group-containing vinyl ethers such as hydroxypentyl vinyl ether and 6-hydroxyhexyl vinyl ether; various vinyl ethers as listed above,
addition reaction product with ε-caprolactone;

2-hydroxyethyl (meth) allyl ether, 3-hydroxypropyl (meth) allyl ether, 2-hydroxypropyl (meth) allyl ether,
4-hydroxybutyl (meth) allyl ether, 3-hydroxybutyl (meth) allyl ether, 2-hydroxy-2-methylpropyl (meth) allyl ether, 5-
Various hydroxyl group-containing allyl ethers such as hydroxypentyl (meth) allyl ether and 6-hydroxyhexyl (meth) allyl ether; addition reaction products of various allyl ethers listed above with ε-caprolactone .

Further, other copolymerizable vinyl monomers can be used, if necessary, but only representative examples of such other copolymerizable monomers are given. If it stays, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate,
Isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth)
Tert-Butyl acrylate or (meth) acrylic acid n
-Hexyl,

Cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate,
2-Methyl acrylate (meth) acrylate, dodecyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate or stearyl (meth) acrylate, such as (meth) acrylic acid alkyl ester,

Benzyl (meth) acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate or tetrahydrofurfuryl (meth) acrylate,

Alternatively, various alkyl carbitol (meth) s such as ethyl carbitol (meth) acrylate
In addition to acrylates, further, various (meth) acryl such as isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate or dicyclopentenyloxyethyl (meth) acrylate. Acid esters;

Various α-olefins such as ethylene, propylene and butene-1; Various halogenated olefins (halo olefins) other than fluoroolefins such as vinyl chloride and vinylidene chloride; Styrene, α
Various aromatic vinyl monomers such as methylstyrene, vinyltoluene;

Dimethyl fumarate, diethyl fumarate, dibutyl fumarate, dioctyl fumarate, dimethyl maleate, diethyl maleate, dibutyl maleate, dioctyl maleate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, dioctyl itaconate. Such as various unsaturated dicarboxylic acids with 1 to 18 carbon atoms
Diesters with monohydric alcohols;

Various amino group-containing amides such as N-dimethylaminoethyl (meth) acrylamide, N-diethylaminoethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide and N-diethylaminopropyl (meth) acrylamide Unsaturated monomers; various dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate;

Tert-Butylaminoethyl (meth) acrylate, tert-butylaminopropyl (meth)
Various amino group-containing monomers such as acrylate, aziridinylethyl (meth) acrylate, pyrrolidinylethyl (meth) acrylate, piperidinylethyl (meth) acrylate; maleic anhydride, itaconic anhydride,
Various acid anhydride group-containing monomers such as citraconic anhydride, anhydrous (meth) acrylic acid, and tetrahydrophthalic anhydride;

Diethyl-2- (meth) acryloyloxyethyl phosphate, dibutyl-2- (meth) acryloyloxybutyl phosphate, dioctyl-2
-(Phosphorus ester group-containing monomers such as meacryloyloxyethyl phosphate and diphenyl-2- (meth) acryloyloxyethyl phosphate);
Various hydrolyzable silyl group-containing monomers such as γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane and γ- (meth) acryloyloxypropylmethyldimethoxysilane;

Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, branched (branched) aliphatic vinyl carboxylate having 9 carbon atoms. ,
Various aliphatic vinyl carboxylates such as branched aliphatic vinyl carboxylates having 10 carbon atoms, branched aliphatic vinyl carboxylates having 11 carbon atoms, and vinyl stearate;

Vinyl cyclohexanecarboxylate, vinyl methylcyclohexanecarboxylate, vinyl benzoate, p
There are various vinyl esters of carboxylic acids having a cyclic structure such as -tert-butyl vinyl benzoate.

The amount of various curing reactive group-containing vinyl monomers as exemplified above is preferably in the range of 10 to 70% by weight based on the total amount of vinyl monomers used. When the amount of the curing-reactive group-containing vinyl monomer used is within the above range, a coating film having excellent mechanical properties and flexibility can be obtained.

As the organic solvent used in preparing the thermosetting acrylic resin, known and commonly used organic solvents can be used.

As typical examples of such organic solvents, methanol, ethanol, n-
Alkyl alcohols such as propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol;

Methyl cellosolve, ethyl cellosolve, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether,
Glycol ethers such as propylene glycol monopropyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether;

Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene; Exxon aromatic naphtha No. 2 (manufactured by Exxon, USA), such as mixed hydrocarbons containing aromatic hydrocarbons; n-pentane, n
-Aliphatic hydrocarbons such as hexane and n-octane;
Isopar C, Isopar E, Exor DSP100
/ 140, Exol D30 (all manufactured by Exxon, USA), IP Solvent 1016 (manufactured by Idemitsu Petrochemical Co., Ltd.), mixed hydrocarbons containing aliphatic hydrocarbons; cyclopentane, cyclohexane, methylcyclohexane,
Alicyclic hydrocarbons such as ethylcyclohexane;

Ethers such as tetrahydrofuran, dioxane, diisopropyl ether, di-n-butyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, acetic acid n -Butyl, isobutyl acetate, n-amyl acetate, isoamyl acetate, hexyl acetate, ethyl propionate, butyl propionate, and other esters.

As the radical polymerization initiator used when preparing the thermosetting acrylic resin, various known and commonly used compounds can be used.

Of these, only typical ones will be exemplified. 2,2'-azobisisobutyronitrile, 2,2'-azobis-methylbutyronitrile, 2,2'- Azobis-2,4-dimethylvaleronitrile, 1,1'-azobis-cyclohexanecarbonitrile, dimethyl-2,2'-azobisisobutyrate, 4,4'-azobis-4-cyanovaleric acid, 2,2 '-
Azobis- (2-amidinopropene) dihydrochloride, 2-t
ert-butylazo-2-cyanopropane, 2,2'-
Azobis (2-methyl-propionamide) dihydrate,
2,2'-azobis [2- (2-imidazolin-2-yl) propene] or 2,2'-azobis (2,2,4-
Various azo compounds such as trimethylpentane);

Alternatively, benzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, potassium persulfate, tert-butyl peroxy neodecanoate, tert-butyl peroxypivalate, tert-butyl peroxy-2-ethylhexano Ate, tert-butyl peroxyisobutyrate, 1,1-bis-tert-butyl peroxy-
3,3,5-Trimethylcyclohexane or tert-
Butyl peroxy laurate,

Tert-butyl peroxyisophthalate, tert-butyl peroxyacetate, tert
-Butyl peroxy benzoate, dicumyl peroxide or di-tert-butyl peroxide; various ketone peroxides; peroxyketals; hydroperoxides; dialkyl peroxides; diacyl peroxides; peroxy Esters; peroxydicarbonates; or hydrogen peroxide.

The number average molecular weight of the thermosetting acrylic resin is preferably in the range of 1,000 to 20,000, and more preferably in the range of 1,500 to 15,000. . When the number average molecular weight of the thermosetting acrylic resin is within the above range, a coating film having excellent smoothness and mechanical properties can be obtained.

The preparation method for obtaining the thermosetting polyester resin to be used as the thermosetting resin (B) is not particularly limited, and a known method for producing a thermosetting polyester resin by polycondensing a polyhydric alcohol and a polybasic acid is used. Various methods are available. As the curing-reactive group, a carboxyl group and / or a hydroxyl group is preferably adopted because of easy preparation.

As the polyhydric alcohol and polybasic acid which can be used as the raw material for the thermosetting polyester resin, various known and commonly used compounds can be used. By adjusting the amounts of these polyhydric alcohol and polybasic acid to be used. A thermosetting polyester resin having a carboxyl group and / or a hydroxyl group can be obtained.

First, as typical examples of the above-mentioned polyhydric alcohols, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5 are given. -Pentanediol, 1,6-hexanediol, neopentyl glycol, triethylene glycol, bis-hydroxyethyl terephthalate,
Cyclohexanedimethanol, octanediol, diethylpropanediol, butylethylpropanediol, 2-methyl-1,3-propanediol, 2,2,2
4-trimethylpentanediol, hydrogenated bisphenol A, ethylene oxide adduct of hydrogenated bisphenol A, propylene oxide adduct of hydrogenated bisphenol A, trimethylolethane, trimethylolpropane,
Examples include glycerin, pentaerythritol, trishydroxyethyl isocyanurate, and hydroxypivalyl hydroxypivalate.

On the other hand, particularly representative examples of the above-mentioned polybasic acids include terephthalic acid, isophthalic acid,
Phthalic acid, methylterephthalic acid, trimellitic acid, pyromellitic acid or their anhydrides; succinic acid, adipic acid, azelaic acid, sebacic acid or their anhydrides; maleic acid, itaconic acid or their anhydrides;
There are fumaric acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid or their anhydrides; cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and the like.

Further, as a raw material of the thermosetting polyester resin, a compound having both a carboxyl group and a hydroxyl group in one molecule, such as dimethanolpropionic acid and hydroxypivalate; "Cadula E10" (manufactured by Shell Co., Netherlands) (Trade name of glycidyl ester of branched aliphatic carboxylic acid); various monohydric alcohols such as methanol, propanol, butanol and benzyl alcohol; benzoic acid, p-tert.
Various monovalent basic acids such as -butylbenzoic acid; various fatty acids such as castor oil fatty acid, coconut oil fatty acid and soybean oil fatty acid can also be used.

As the polyester resin obtained by using various polyhydric alcohols, polybasic acids and other raw materials as listed above, the total of the acid value and the hydroxyl value is 10
To 250 (mgKOH / g; the same applies below),
In addition, it is desirable to use a resin having a number average molecular weight in the range of 500 to 10,000.

When the sum of the acid value and the hydroxyl value is within the above range, a coating film having excellent smoothness and mechanical properties can be obtained. Further, when the number average molecular weight is within the above range, not only a coating film having excellent smoothness and mechanical properties can be obtained, but also a coating having excellent storage stability can be obtained.

The structure of the thermosetting polyester resin is
It is not particularly limited as long as it is within the range of various characteristic values of the resin as described above, and may have a branched structure or a linear structure.

The epoxy resin which can be used as the thermosetting resin (B) is not particularly limited, and examples thereof include epoxy resins such as polyglycidyl ether of bisphenol-A.

The thermosetting fluororesin usable as the thermosetting resin (B) refers to a polymer compound having a fluorine atom in the molecule, specifically, polytetrafluoroethylene or polyvinylidene fluoride. And a (tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) copolymer obtained by (co) polymerizing one or more fluorine-containing vinyl monomers (b-1), (Per) Fluoroalkyl polyether, (Per)
Fluoroalkyl polycarbonate and the like,
In particular, the fluorine-containing vinyl monomer (b-1), the vinyl ether (b-2) and / or the carboxylic acid vinyl ester (b-3) are further co-used with other vinyl monomers, if necessary. A thermosetting fluororesin obtained by polymerization is excellent in coating properties such as weather resistance and mechanical properties, and also excellent in solubility in an organic solvent, and therefore can be preferably used.

To prepare these heat-curable fluororesins, known and conventional methods can be applied. For example, the fluorine-containing vinyl monomer (b-1) and vinyl ether (b-) can be used.
2) and / or carboxylic acid vinyl ester (b-3)
Is used together with other vinyl monomers, if necessary, and each of these monomers is polymerized in an organic solvent, which is recommended because it is the simplest method.

The above-mentioned fluorine-containing vinyl monomer (a-1) used at that time has a fluorine atom in the molecule,
Moreover, it refers to a compound having a form such that it also has a polymerizable unsaturated double bond (hereinafter, also referred to as an unsaturated double bond), and preferably such fluorine-containing vinyl monomers In the case of polymerization of
V)

[0066]

[Chemical 1]

[However, W, X, Y and Z in the formula are
Each of them represents a hydrogen atom, a halogen atom, an alkyl group or a halogenated alkyl group, which may be the same or different, and W, X, Y
Alternatively, at least one of Z is a fluorine atom. ] The fluoroolefin structural unit represented by
The term refers to a compound that can be introduced into the main chain.

Of these, particularly representative ones are exemplified, vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene,
Various fluorine-containing α-olefins such as chlorotrifluoroethylene, bromotrifluoroethylene, pentafluoropropylene, hexafluoropropylene;
Such as trifluoromethyl trifluorovinyl ether, pentafluoroethyl trifluorovinyl ether, heptafluoropropyl trifluorovinyl ether,
Examples include various perfluoroalkyl-perfluorovinyl ethers; various (per) fluoroalkyl vinyl ethers (provided that the alkyl group has 1 to 18 carbon atoms).

These fluorine-containing vinyl monomers (a-1)
May be used alone or in combination of two or more,
Since a copolymer having excellent weather resistance can be obtained, vinyl fluoride, vinylidene fluoride, trifluoroethylene,
It is desirable to use at least one fluorine-containing vinyl monomer selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene.

Further, it is desirable to use the above-mentioned vinyl ether (b-2) and / or carboxylic acid vinyl ester (b-3) for the thermosetting fluororesin. These vinyl ethers (b-2) and / or carboxylic acid vinyl esters (b-3) are excellent in copolymerizability with the fluorine-containing vinyl monomer (b-1), and therefore, in the thermosetting fluororesin. It can be said that fluorine atoms can be introduced efficiently.

As typical examples of the vinyl ether (b-2), methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether,
Isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether and the like, and further, 2-ethylhexyl vinyl ether, chloromethyl vinyl ether, chloroethyl vinyl ether, benzyl vinyl ether, phenethyl ethyl vinyl ether and the like. , Various (substituted) alkyl vinyl ethers or aralkyl vinyl ethers; various cycloalkyl vinyl ethers such as cyclopentyl vinyl ether, cyclohexyl vinyl ether, and methyl cyclohexyl vinyl ether.

On the other hand, carboxylic acid vinyl ester (b-
3) Particularly representative are vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl stearate; a branch having 9 carbon atoms. A branched (branched) aliphatic vinyl carboxylate, a branched (branched) aliphatic vinyl carboxylate having 10 carbon atoms, a branched (branched) aliphatic vinyl carboxylate having 11 carbon atoms, Various aliphatic carboxylic acid vinyl esters; various carboxylic acid vinyl esters having a cyclic structure, such as vinyl cyclohexanecarboxylate, vinyl methylcyclohexanecarboxylate, vinyl benzoate and vinyl p-tert-butylbenzoate. is there.

In addition to the compounds listed above, other vinyl monomers such as those mentioned for the thermosetting acrylic resin can be used, if desired.

As a method of introducing a curing reactive group into a thermosetting fluororesin, a method of copolymerizing monomers having a curing reactive group with the above-mentioned monomers is easy. It is recommended that a curing reactive group can be introduced into the thermosetting fluororesin. From the viewpoint of storage stability of the powder coating material produced using the thermosetting fluororesin and excellent coating film properties, the curing reactive group is at least one of a hydroxyl group, a carboxyl group, and an epoxy group. Is desirable.

As typical examples of such curing reactive group-containing monomers, the hydroxyl group-containing vinyl monomers include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, and 4-hydroxyethyl vinyl ether. Various hydroxyl group-containing vinyl ethers such as hydroxybutyl vinyl ether; addition reaction products of these hydroxyl group-containing vinyl ethers and ε-caprolactone; 2-hydroxyethyl (meth) allyl ether, 3-hydroxypropyl (meth) allyl ether, Various hydroxy group-containing allyl ethers such as 4-hydroxybutyl (meth) allyl ether;
Addition reaction product with ε-caprolactone; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) Acrylate, 3-hydroxybutyl (meth) acrylate
Group, a hydroxyl group-containing (meth) acrylate compound such as 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate; Examples thereof include addition reaction products of (meth) acrylate and ε-caprolactone.

Examples of the carboxyl group-containing monomers include (meth) acrylic acid, crotonic acid, itaconic acid,
Various carboxyl group-containing monomers such as maleic acid and fumaric acid; monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monoisobutyl fumarate, monotert-butyl fumarate, monohexyl fumarate,
Monooctyl fumarate, mono-2-ethylhexyl fumarate, monomethyl maleate, monoethyl maleate, monobutyl maleate, monoisobutyl maleate, monotert-butyl maleate, monohexyl maleate, monooctyl maleate, mono-2-maleate. Monoesters of various α, β-unsaturated dicarboxylic acids such as ethylhexyl and monohydric alcohols having 1 to 18 carbon atoms; monomethyl itaconate, monoethyl itaconate,
There are monoalkyl esters of itaconate such as monobutyl itaconate, monoisobutyl itaconate, monohexyl itaconate, monooctyl itaconate and mono-2-ethylhexyl itaconate.

Examples of the epoxy group-containing monomers include glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, (3,4-epoxy-butyl) methacrylate, and (2-oxo-1,3-). Epoxy group-containing (meth) acrylates such as oxolane) methyl (meth) acrylate and 3,4-epoxycyclohexylmethyl (meth) acrylate; (2-oxo-
1,3-oxolane) vinyl methanecarboxylate, 3,4
-Epoxy group-containing carboxylic acid vinyl esters such as epoxycyclohexanecarboxylic acid vinyl ester; glycidyl vinyl ether, epoxy group-containing vinyl ethers such as 3,4-epoxycyclohexyl vinyl ether; epoxy group-containing allyl ethers such as allyl glycidyl ether and so on.

In addition to the above-mentioned curing reactive group-containing monomers, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; N-dimethylaminoethyl (meth) acrylamide, N Various amino group-containing amide unsaturated monomers such as diethylaminoethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide, N-diethylaminopropyl (meth) acrylamide;

Various dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; tert-butylaminoethyl (meth) acrylate, tert-butylaminopropyl (meth) acrylate , Aziridinylethyl (meth) acrylate,
Various amino group-containing monomers such as pyrrolidinylethyl (meth) acrylate and piperidinylethyl (meth) acrylate;

Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldiethoxysilane, vinyltris (β-methoxyethoxy) silane, allyltrimethoxysilane, trimethoxysilylethyl vinyl ether, triethoxysilylethyl vinyl ether, Methyldimethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether, triethoxysilylpropyl vinyl ether,
Methyldiethoxysilylpropyl vinyl ether, γ-
Various monomers having a hydrolyzable silyl group such as (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane or γ- (meth) acryloyloxypropylmethyldimethoxysilane Also, it can be used as a monomer having a curing reactive group.

To prepare the thermosetting fluororesin by the solution polymerization method, all the monomers, the polymerization initiator and the solvent are charged in a reactor at once and polymerized, or the fluorine-containing vinyl monomer (b- 1) and a reactor charged with a solvent, the monomer other than the fluorine-containing vinyl monomer (b-1) and a polymerization initiator are added continuously or in a divided manner to polymerize, Furthermore, it is possible to apply a method in which all the monomers and the polymerization initiator are added to the reactor charged with only the solvent continuously or in a divided manner to perform polymerization. As the polymerization initiator and solvent used at that time, known and conventional ones can be used as they are.

The fluorine content of the thermosetting fluororesin is 1
It is desirable to be 5% by weight or more. Fluorine content is 1
If it is 5% by weight or more, sufficient weather resistance can be imparted to the coating film formed using the thermosetting fluororesin.

The softening point of the thermosetting fluororesin is 80 to 1
It is desirable that the temperature is in the range of 50 ° C. When the softening point is within the above range, it is possible to obtain a powder coating excellent in both appearance of the coating film and storage stability.

Further, the number average molecular weight of the thermosetting fluororesin is preferably in the range of 500 to 50,000, and particularly preferably in the range of 1,000 to 10,000. If the number average molecular weight is within the above range,
A coating film having excellent weather resistance, mechanical properties and smoothness can be obtained.

The thermosetting resin (B) has a curing reactive group capable of reacting with the curing reactive group of the organopolysiloxane (A) from the viewpoint of improving the weather resistance and mechanical properties of the coating film. Preferably. Further, a part of the curing reactive group of the thermosetting resin (B) is reacted with all or a part of the curing reactivity of the organopolysiloxane (A), which is modified with the organopolysiloxane (A). The thermosetting resin (B) is more preferable.

As a method for preparing the thermosetting resin (B) modified with the organopolysiloxane (A), known and conventional methods can be adopted. For example, when the thermosetting resin (B) is synthesized, the organopolysiloxane (A) is used as a part of the raw material, or after the thermosetting resin (B) is synthesized, the organopolysiloxane (A) is added. A reaction method or a combination of these two methods is used by synthesizing organopolysiloxane (A) as a part of the raw material of thermosetting resin (B), and the obtained resin is further organopolysiloxane (A). The method of reacting can also be adopted.

Next, the curing agent (C) will be described. As the curing agent (C), one having a curing reactive group capable of reacting with the thermosetting resin (B) can be used, and a coating film having excellent mechanical properties is formed. Furthermore, organopolysiloxane (A)
The weather resistance of the coating film is further improved by using the curing agent capable of reacting with the curing reactive group.

Curing agent (C) used in the present invention
The one that is usually used for powder coatings is appropriately selected and used according to the type of the curing reactive group of the thermosetting resin (B).

As the curing agent (C), when the curing-reactive group of the thermosetting resin (B) is an epoxy group, only typical ones are exemplified. Succinic acid, glutaric acid, Adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, eicosanedioic acid,
Maleic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, trimellitic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexene-1,2-dicarboxylic acid, trimellitic acid, pyromellitic acid, or There are such acid anhydrides and urethane modified products, and among them, since the coating film physical properties and storage stability are excellent, an aliphatic dibasic acid is preferable, and particularly since the coating film physical properties are excellent, dodecanedioic acid is particularly preferable. .

When the curing-reactive group of the thermosetting resin (B) is a carboxyl group, only representative examples of the curing agent (C) are listed, and the polyglycidyl ether of bisphenol A is Such as various epoxy resins; glycidyl group-containing acrylic resins, epoxy group-containing acrylic resins, polyglycidyl ethers of various polyhydric alcohols such as 1,6-hexanediol, trimethylolpropane and trimethylolethane; phthalates Acid, terephthalic acid, isophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, trimellitic acid, pyromellitic acid, polyglycidyl esters of various polycarboxylic acids; bis (3,4-epoxycyclohexyl) Various alicyclic epoxy group-containing compounds such as methyl adipate; Triglycidyl isocyanurate, β-
Examples thereof include hydroxyamides such as hydroxyalkylamides.

When the curing-reactive group of the thermosetting resin (B) is a hydroxyl group, a polyblock isocyanate compound, aminoplast and the like are particularly preferable as the curing agent (C).

As the polyblock polyisocyanate compound, only representative ones are exemplified, and various aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate;
Various cycloaliphatic diisocyanates such as xylylene diisocyanate and isophorone diisocyanate; organic diisocyanates such as various aromatic diisocyanates such as tolylene diisocyanate and 4,4′-diphenylmethane diisocyanate, or organic diisocyanates thereof; There are polyhydric alcohols, low molecular weight polyester resins (polyester polyols) or adducts with water, etc.,

Further, various organic polyisocyanates such as those listed above (including isocyanurate type polyisocyanate compounds), and various polyisocyanate compounds such as isocyanate biuret compounds are formed into known and commonly used blocks. Examples thereof include those obtained by blocking with an agent, so-called self-blocked polyisocyanate compounds having a uretdione bond as a structural unit, and the like.

On the other hand, examples of aminoplasts include melamine, urea, acetoguanamine, benzoguanamine,
Various amino group-containing compounds such as steroganamin and spiroguanamine, and formaldehyde, paraformaldehyde, acetaldehyde and glyoxal,
Condensates in the form obtained by reacting various aldehyde compound components with various conventionally known methods, or compounds in the form obtained by etherifying these condensates with alcohols and so on.

As only specific examples of such aminoplasts, hexamethoxymethylolmelamine, hexabutyletherified methylolmelamine, methylbutyl-mixed etherified methylolmelamine, methyletherified methylolmelamine, n-butyletherified methylol. Melamine, isobutyl etherified methylol melamine, or their condensates; various bicyclic compounds such as hexamethoxyglycoluril, hexabutoxyglycoluril, tetramethoxymethylglycoluril; aliphatic dibasic acids and diethanolamine, etc. Various acid amides in the form of being obtained by condensation reaction with various alkanolamines; Polymerizable monomers such as butyl ether of N-methylolacrylamide Alone, or other such as obtained by copolymerizing possible Naru monomers and copolymerization reaction, and the like various polymer compounds.

The above-mentioned hexamethoxymethylol melamine is "Cymel 300, 301 or 303" (manufactured by Mitsui Cyanamid Co.); methylbutyl mixed etherified methylol melamine is "Cymel 238, 2".
32 or 266 "(manufactured by Mitsui Cyanamid); n-butyl etherified methylol melamine as" Super Beckamine L-164 "(manufactured by Dainippon Ink and Chemicals, Inc.); tetramethoxymethylglycoluril as" Powder Link " (POWDERLIN
K) 1174 ”(product of American Cyanamid Co., USA); acid amides are“ PRIMID (PRIMI)
D) XL-552 "," Primid (PRIMID)
QM-1260 "(manufactured by EMS), which is commercially available.

The above curing agent (C) may be used alone or in combination of two or more kinds. The compounding amount of the curing reactive group of the thermosetting resin (B) and the curing agent (C) is such that the equivalent ratio of the curing reactive group of the thermosetting resin (B) to the equivalent amount of the curing agent (C) is 2. It is preferably between 0 and 0.5.

The above-mentioned organopolysiloxane (A) and thermosetting resin (B) or curing agent (C)
A powder in which the organopolysiloxane (A) and the thermosetting resin (B) or the curing agent (C) are completely and uniformly mixed by spray drying an organic solvent solution dissolved or dispersed in the organic solvent (D). In order to obtain a body mixture, the powder mixture is used as a raw material for a powder coating material to produce a powder coating material by a known and common production method such as a melt kneading method. ), A thermosetting resin (B) and a curing agent (C) are dry-blended and then melt-kneaded, the storage stability of the powder coating material can be significantly improved and a coating film can be obtained. The weather resistance of can also be improved.

Furthermore, an organopolysiloxane (A),
The powder coating obtained by spray-drying an organic solvent solution in which a thermosetting resin (B) and a curing agent (C) are dissolved in an organic solvent (D) is a coating film obtained in addition to the above-mentioned features. Is particularly preferable because it has excellent smoothness, sharpness and mechanical properties.

Next, the organic solvent (D) used in the present invention will be described. As the organic solvent (D), a known and commonly used solvent that dissolves the thermosetting resin (B) and / or the curing agent (C) can be used, and one kind or two or more kinds of solvents may be used in combination, When the thermosetting resin (B) can be obtained by solution polymerization, the solvent used in the polymerization can be used as it is as a part or the whole of the organic solvent (D).

The thermosetting resin (B) and the curing agent (C)
Even an organic solvent that does not dissolve both of them can be used as a part of the organic solvent (D) as long as it does not impair the storage stability of the powder coating material solution.

As typical examples of the organic solvent (D), methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol and tert can be given.
-Alkyl alcohols such as butanol, n-pentanol, isopentanol;

Methyl cellosolve, ethyl cellosolve, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether,
Glycol ethers such as propylene glycol monopropyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether;

Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene; Exxon aromatic naphtha No. 2 (manufactured by Exxon, USA), such as mixed hydrocarbons containing aromatic hydrocarbons; n-pentane, n
-Aliphatic hydrocarbons such as hexane and n-octane;
Isopar C, Isopar E, Exor DSP100
/ 140, Exol D30 (all manufactured by Exxon, USA), IP Solvent 1016 (manufactured by Idemitsu Petrochemical Co., Ltd.), mixed hydrocarbons containing aliphatic hydrocarbons; cyclopentane, cyclohexane, methylcyclohexane,
Alicyclic hydrocarbons such as ethylcyclohexane;

Ethers such as tetrahydrofuran, dioxane, diisopropyl ether, di-n-butyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, acetic acid n -Butyl, isobutyl acetate, n-amyl acetate, isoamyl acetate, hexyl acetate, ethyl propionate, butyl propionate, and other esters;

From the standpoint of improving the drying property of the paint particles during spray drying, 65 to 100% by weight of the organic solvent (D) has a boiling point of 100 ° C. or less at normal pressure.
It is preferable to occupy

When the curing agent (C) is an aliphatic dibasic acid, the organic solvent contains at least one alcohol having a carbon number of 4 or less in order to increase the solubility of the curing agent, and The amount of alcohol of the number 4 or less is 4 by weight ratio with respect to the aliphatic dibasic acid contained in the powder coating raw material solution.
It is preferably double or more.

Further, it is desirable that the organic solvent (D) contains a high boiling point solvent (D1) having a boiling point of 150 to 300 ° C. under normal pressure. By using the high boiling point solvent (D1) as a part of the organic solvent (D) and leaving the high boiling point solvent (D1) in the powder coating after spray drying, coating films such as armpits and pinholes It is possible to obtain a powder coating material that forms a coating film that does not cause defects, and the coating film appearance is improved. The high boiling point solvent (D1) may be a single component or a mixture of a plurality of components.

As the boiling point of the high boiling point solvent (D1) at normal pressure, a boiling point of 170 to 250 ° C. is more preferably used. Furthermore, the boiling point at normal pressure is +15 to +1 with respect to the temperature when baking and curing the powder coating material of the present invention.
Those at 50 ° C. are particularly preferable.

The amount of the high boiling point solvent (D1) used is preferably 0.005 to 3 parts, and 0.0 to 3 parts, based on 100 parts of the powder coating material.
1 to 2 parts is more preferable, and 0.05 to 1 part is even more preferable.

When the boiling point and the amount of the high boiling point solvent (D1) at normal pressure are within the above ranges, formation of coating defects such as cracks and pinholes during bake hardening can be prevented.

Specific examples of such high boiling point solvents (D1) include, but are not limited to, alcohols such as n-hexanol, n-octanol, 2-ethylhexanol, cyclohexanol and benzyl alcohol; ethylene glycol, propylene glycol. , Polyhydric alcohols such as glycerin; butyl cellosolve, hexyl cellosolve, ethylene glycol dipropyl ether,
Such as ethylene glycol dibutyl ether, propylene glycol monobutyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, methyl carbitol, ethyl carbitol, butyl carbitol, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether , Glycol ethers;

Aromatic hydrocarbons such as propylbenzene, butylbenzene, pentylbenzene, diethylbenzene, dipropylbenzene, dipentylbenzene, dodecylbenzene, cyclohexylbenzene; Solvesso 1
00, Solvesso 150, Solvesso 200 (all manufactured by Exxon, USA); mixed hydrocarbons containing aromatic hydrocarbons; Exxon Naphtha No. 3, Exxon naphtha No. 5, Exxon Naphtha No. 6, Exxon Solvent No. 7, Isopar G, Isopar H, Isopar L, Isopar M, Exol D40, Exol D90, Exol D110 (all manufactured by US Exxon Corporation), IP Solvent 1620, IP Solvent 202
Mixed hydrocarbons containing aliphatic hydrocarbons such as 8 (manufactured by Idemitsu Petrochemical Co., Ltd.), Merbeil 20, Merbeil 30, Merbeil 40 (manufactured by Showa Shell Sekiyu Co., Ltd.), and mineral spirits;

Glycerin alkyl ether, glycerin alkyl ester; ketones such as diisobutyl ketone, methyl amyl ketone, cyclohexanone and isophorone; cyclohexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, isoamyl propionate, butyric acid alkyl ester Esters such as, stearic acid alkyl ester, benzoic acid alkyl ester, adipic acid dialkyl ester, phthalic acid dialkyl ester;

Examples include N-methylpyrrolidone, dimethylformamide, dimethylacetamide and ethylene carbonate.

Among the above high boiling point solvents (D1), the use of an aromatic solvent and / or an aliphatic solvent is preferably used because the effect of preventing the generation of coating film defects is more remarkable.

The method of adding the high boiling point solvent (D1) to the powder coating material is not particularly limited. For example, in the case of producing the powder coating material by the melt kneading method, other methods may be used when blending the coating material. It is sufficient to mix with the other raw materials, and in the case of producing the powder coating material by the spray drying method, when preparing the powder coating raw material solution, a method of mixing and dissolving with other raw materials or the powder coating raw material solution is used. The method of adding and mixing immediately before spray drying is recommended because it is simple and easy. When the thermosetting resin (B) is obtained by solution polymerization,
A method of adding as a part of the polymerization solvent at the time of polymerization or a method of adding after completion of the polymerization can be adopted.

Next, the powder coating material solution will be described.
The powder coating material raw material solution of the present invention is an organic solvent solution containing a coating film forming component, and the powder coating material of the present invention is obtained by spray drying the powder coating material raw material solution.

The method for preparing the powder coating material solution is not particularly limited. For example, the organopolysiloxane (A), the thermosetting resin (B) and the curing agent (C) are added to the organic solvent (D). In addition, it can be prepared by stirring and mixing at room temperature to dissolve the organopolysiloxane (A), the thermosetting resin (B) and the curing agent (C).

The powder coating material solution used in the present invention is
At a temperature lower than the temperature when spraying, for example, at room temperature,
It is preferable that the thermosetting resin and the curing agent are completely dissolved in the organic solvent. When it is completely dissolved, the thermosetting resin and the curing agent are more uniformly mixed, and the appearance of the coating film, especially of the coating film, as compared with the mixing by melt kneading which is performed in the conventional manufacturing method. This is because it is possible to obtain a powder coating material with significantly improved sharpness.

Further, if necessary, pigments, other resins, curing catalysts, additives and the like may be added to the powder coating material solution and dissolved or dispersed to form a coating material. As typical examples of pigments, titanium oxide, red iron oxide, chromium titanium yellow, yellow iron oxide, various inorganic pigments of carbon black, phthalocyanine blue,
Phthalocyanine series such as phthalocyanine green, anthraquinone series such as induslen blue, dianthraquinonyl red, quinacridone series, lake red, fast yellow, disazo yellow, azo series such as permanent red, nitro series such as naphthol yellow, pigment green B, Various conventionally known organic pigments such as naphtho green such as naphthol green, various commonly used extender pigments, and various conventionally known bright (metallic) pigments such as aluminum flakes and mica flakes. Etc. are used. A colored powder coating material can be prepared by dispersing the above pigment in a powder coating material solution and then spray drying. As a method for dispersing the pigment in the powder coating material solution, a known and commonly used method such as a sand mill can be used. Further, a colored powder coating material may be manufactured by mixing a plurality of colored powder coating material solutions to adjust the color, preparing a colored powder coating material solution having a desired color, and spray-drying.

As only other typical resins, acrylic resins, polyester resins, fluororesins, silicone resins, chlorinated polyethylene, chlorinated polypropylene, petroleum resins, epoxy resins, chlorinated resins are given. Examples include various resins such as rubber, and resins other than the base resin (A) and the curing agent (B).

As the curing catalyst, known and conventional ones can be used as they are, depending on the combination of the main resin (A) and the curing agent (B). Examples of the additives include flow regulators, color separation inhibitors, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, and other known and commonly used additives.

Further, if necessary, nitrocellulose,
Various fibrin derivatives such as cellulose acetate butyrate may be used.

Next, spray drying will be described. The apparatus used for spray drying may be one capable of removing the organic solvent from the sprayed powder coating material solution, for example, by contacting the sprayed powder coating material solution with a heat source gas to volatilize the organic solvent. A spray drying device or the like can be used. Since the organic solvent is volatilized, it is desirable that the device be explosion proof. Further, from the viewpoint of keeping the vapor content of the solvent in the heat source gas low, which is used for drying the sprayed powder coating material raw material solution, it is desirable to provide a solvent recovery device.

In the case of using the above spray dryer for contacting the sprayed powder coating material solution with the heat source gas to volatilize the organic solvent, the method of contacting the powder coating material solution with the heat source gas is not particularly limited. Instead, any method such as a co-current type, a counter-current type, a co-current / counter-current mixed type, which is commonly used, may be used. The pressure in the device may be normal pressure, reduced pressure or increased pressure, and is not particularly limited.

Regarding the spraying method of the powder coating material solution,
Any of known and conventional types such as a rotating disk type, a two-fluid nozzle type, and a pressure nozzle type can be used. Factors for controlling the particle size during spraying include the rotation speed of the disk in the rotary disk system, the discharge speed from the nozzle in the two-fluid nozzle system, and the compression used by mixing with the raw material solution. The mixing ratio of air and the raw material solution, and the pressure nozzle type include the discharge pressure and the like, but these values may be appropriately determined according to the target particle size.

The feed rate of the raw material solution and the flow rate of the heat source gas may be appropriately determined in accordance with the target particle size, but if the feed rate of the raw material solution and the flow rate of the heat source gas change during spray drying, Since the particle size, particle size distribution and non-volatile content of the obtained particles also change, it is desirable to keep it constant during spray drying.

The non-volatile content concentration of the powder coating material solution at the time of spray drying may be appropriately determined according to the specifications of the spray dryer and the spray drying conditions.

Usually, the heat source gas containing particles obtained by spray drying is continuously guided to a classifying apparatus represented by a cyclone, and particles are collected and classified. In order to adjust the particle size distribution of the powder coating material of the present invention, when it is necessary to perform classification for removing coarse particles and fine particles, a commercially available general classifier can be used.

An inert gas is desirable as the heat source gas. Above all, it is preferable to use nitrogen gas in terms of cost and the like. The temperature of the heat source gas is a temperature at which the thermosetting resin and the curing agent of the powder coating material solution do not substantially cause a curing reaction, that is, the coating material of the powder coating obtained even if a partial curing reaction occurs. The temperature may be appropriately determined within a temperature range in which the performance as is not substantially impaired. The lower limit of the temperature of the heat source gas is not particularly limited, but in order to evaporate the solvent efficiently, it is preferably 20 ° C. or higher, and more preferably 30 ° C. or higher. Usually, the temperature of the heat source gas is 20 to 160 ° C, preferably 30 to 13 ° C.
It is appropriately determined within the range of 0 ° C.

Further, in order to more efficiently evaporate the solvent, the powder coating material solution may be preheated before spray drying. At this time, the temperature for preheating is preferably 70 ° C. or lower in order to prevent gelation of the powder coating material raw material solution, and spray drying is preferably performed as soon as possible after preheating.

The powder coating material thus obtained can be used as it is, but if necessary, it may be secondarily dried by another drying method such as vacuum drying, aeration drying and fluidized bed drying. . At that time, in order to prevent gelation of the powder coating material or heat fusion of the coating particles, secondary drying is performed at about 7
It is desirable to carry out at a temperature of 0 ° C. or lower.

Further, the obtained powder coating material may be further used by adjusting the particle diameter by a pulverizing step or a granulating step, if necessary.

The powder coating material of the present invention has an average particle diameter of 5 to 5.
It is preferably 50 μm. Considering the smoothness of the thin film, the thickness is more preferably 10 to 30 μm. The above average particle diameter means a volume average median diameter, and for example, a laser diffraction particle size analyzer (SALD-2 manufactured by Shimadzu Corporation).
000).

The powder coating material of the present invention preferably has an average circularity of 0.9 or more. Average circularity 0.
By using a spherical powder coating of 9 or more, the fluidity and repaintability of the coating are improved. From this viewpoint, it is preferable that the particles having a circularity of 0.9 or more have a frequency of 50% or more, and more preferably 70% or more.

The powder coating material of the present invention is spray-dried with a powder coating material solution in which an organopolysiloxane (A), a thermosetting resin (B) and a curing agent (C) are dissolved in an organic solvent (D). In the case of producing by the above method, the obtained powder coating material is essentially spherical, so that it is particularly preferable as a production method.

The circularity and the average circularity referred to here are one of the particle shape indexes representing the unevenness of the particle surface,
It is expressed as the following equation.

Circularity = (perimeter of a circle having the same area as the projected area of the particle) / (perimeter of the projected image of the particle)

Therefore, the circularity becomes 1 if the particle image is a perfect circle, and becomes smaller as the particle image deviates from the perfect circle and becomes elongated or uneven. The average circularity is calculated by dividing the sum of the circularity of each particle by the total number of particles. The shape and average circularity of the above powder coating material are determined by a flow type particle image analyzer (FPIA-
1000, manufactured by Toa Medical Electronics Co., Ltd. The shape of the powder coating material can also be confirmed by a scanning electron microscope.

Regarding the coating method of the powder coating material of the present invention,
The base material to be coated is coated by various known and conventional methods such as an electrostatic spraying method, a triboelectrification coating method, and fluidized dipping.
It suffices to carry out baking at a temperature of about 250 ° C. In this way, a powder coated article can be obtained.

The powder coating material of the present invention can be suitably used as an undercoat coating material or a topcoat coating material in a coating film forming method for forming a single-layer or multi-layer coating film on an object to be coated.

Here, the article to be coated refers to a base material to which the coating material is applied, and more specifically, it is an unpainted metal material such as an unpainted steel plate or an untreated or chemically treated aluminum substrate. Examples include base materials used for road vehicles such as automobile bodies and motorcycle bodies, base materials used for automobile parts such as aluminum wheels, and base materials used for beverage cans. Also included are base materials used for road vehicles such as automobile bodies that have been subjected to electrodeposition coating. Furthermore, base materials used for home appliances, vending machines, steel furniture, etc., such as electrogalvanized steel sheets, hot-dip galvanized steel sheets, roof tiles; glasses; or various inorganic building materials; gates or fences Various building materials, such as aluminum; Aluminum sashes,
Various building interior and exterior materials are also exemplified.

These base materials may be processed into a shape according to the final use, or may be a form to which a PCM (pre-coat metal) coating method is applied, that is, a roughly flat plate-like base material. However, after the coating film is formed by the method of the present invention, the coating film may be bent into a predetermined shape according to the purpose, or may be completely post-processed such as coil coating. It may be a base material used in a coating system.

The powder coating material obtained by the production method of the present invention is applied to various kinds of substrates to be coated as described above by a conventional method, and then baked and dried by a conventional method. It is possible to provide a coating film having excellent curability, appearance, weather resistance and mechanical properties, among others.

[0146]

EXAMPLES Next, the present invention will be described more specifically by reference examples, examples and comparative examples, but it goes without saying that the present invention is not limited to these examples.
In the following, all "parts" mean "parts by weight" unless otherwise specified.

Reference Example 1 [Preparation of Thermosetting Acrylic Resin (B)] 1800 parts of methyl ethyl ketone was charged into a stainless steel autoclave whose internal air was replaced with nitrogen gas.
The temperature was raised to 135 ° C. 600 parts of styrene, 900 parts of methyl methacrylate, 600 parts of n-butyl methacrylate, 900 parts of glycidyl methacrylate, ter
A mixture of 230 parts of t-butyl peroxyoctoate and 600 parts of methyl ethyl ketone was added dropwise over 6 hours. After completion of the dropping, the temperature is kept at the same temperature for 5 hours to complete the polymerization reaction, whereby a thermosetting acrylic resin having an epoxy equivalent of 520 (g / equivalent) and a number average molecular weight of 2,300 (B-1 ) Solution (B'-1)
(Nonvolatile matter 57.5%) was obtained. Property values are shown in Table 1 (1)
Shown in.

[0148]

[Table 1]

[0149] << Footnotes in Table 1 >> TBPO: tert-butyl peroxy octoate MEK ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Methyl ethyl ketone

Reference Example 2 [Preparation of Thermosetting Polyester Resin (B)] 195 parts of ethylene glycol and 978 parts of neopentyl glycol are placed in a reaction vessel equipped with a stirrer, a thermometer, a rectification column and a nitrogen gas inlet. After charging, the temperature was raised to 150 ° C. while continuing stirring under a nitrogen atmosphere, then 1500 parts of terephthalic acid, 300 parts of hexahydrophthalic anhydride, 27 parts of trimethylolpropane and 2 parts of dibutyltin oxide were charged and stirred. While continuing, the temperature was raised to 240 ° C.

Further, at the same temperature, the hydroxyl value of the resin is 58.
By continuing the dehydration condensation reaction until it became (mgKOH / g), a thermosetting polyester resin (B-2) having a number average molecular weight of 2,500 was obtained. Property value is first
It shows in Table (2).

Reference Example 3 (same as above) A reaction vessel equipped with a stirrer, thermometer, rectification column and nitrogen gas inlet was charged with 861 parts of neopentyl glycol and 265 parts of cyclohexane dimethanol and stirred under a nitrogen atmosphere. While continuing to raise to 150 ℃, then,
835 parts of isophthalic acid, 1030 parts of terephthalic acid, 9 parts of trimethylolpropane and 2 parts of dibutyltin oxide were charged, and the temperature was raised to 240 ° C. while continuing stirring.

Furthermore, at the same temperature, the acid value of the resin is 50 (mg
The thermosetting polyester resin (B-3) having a number average molecular weight of 2,400 was obtained by continuing the dehydration condensation reaction until it reached KOH / g). Property values are shown in Table 1 (2).

[0154]

[Table 2]

Reference Example 4 (Organopolysiloxane (A))
Preparation Example of Thermosetting Polyester Resin (B-4) Modified by (3) In a reaction vessel equipped with a stirrer, a thermometer, a rectification column and a nitrogen gas inlet, 195 parts of ethylene glycol and 978 parts of neopentyl glycol are added. After charging, the temperature was raised to 150 ° C. while continuing stirring under a nitrogen atmosphere, then 1500 parts of terephthalic acid, 300 parts of hexahydrophthalic anhydride, 27 parts of trimethylolpropane and 2 parts of dibutyltin oxide were charged and stirred. While continuing, the temperature was raised to 240 ° C.

Further, at the same temperature, the resin has a hydroxyl value of 58.
After allowing the dehydration condensation reaction to reach (mgKOH / g), the temperature was lowered to 200 ° C. Next, 300 parts of "Toray Silicone SH-6018" (a silanol group-containing organopolysiloxane having a cyclic siloxane structure, manufactured by Toray Silicone Co., Ltd.) was charged, and the hydroxyl value of the resin was 35 (mgKOH / By continuing the dehydration condensation reaction until g), a thermosetting polyester resin (B-4) modified with an organopolysiloxane (A) having a number average molecular weight of 3,500 was obtained.

Reference Example 5 (Organopolysiloxane (A)
Preparation Example of) 250 g of water and 400 g of toluene were put into a reaction vessel.
While maintaining the liquid temperature of this system at 10 ° C, a mixed liquid of 300 g of phenyltrichlorosilane and 200 g of toluene was added dropwise. After completion of dropping, the mixture was heated under reflux for 6 hours, and then the toluene solution was separated. This toluene solution was repeatedly washed with 300 g of water until the washing liquid became neutral. Then, this toluene solution is heated under reduced pressure to distill off the toluene, thereby obtaining a white solid organopolysiloxane 177.7.
g was obtained.

51. of the obtained organopolysiloxane
6 g, 2-glycidoxypropyltrimethoxysilane 23.6 g, toluene 159.4 g, and cesium hydroxide 0.08 g were charged into the reaction vessel. 5.0 g of water in this system
Was added, and then the produced methanol and water were distilled off while heating the system. After distilling off water, the system was cooled and an additional 5.0 g of water was added to the system. Then, while the system was heated, the produced methanol and water were distilled off. This operation was repeated, the distilled water was extracted with ether, and this was analyzed by gas chromatography to confirm that no methanol was produced, and heating was terminated. Then, the concentration of the solid content was adjusted to 30% by weight, and the mixture was heated and refluxed again.

The system was cooled after sampling every hour, neutralizing the sample, measuring the molecular weight, and confirming that the molecular weight distribution became constant. After cooling, 0.05 g of acetic acid was added to this system for neutralization. Then
By filtering the formed salt and heating the filtrate under reduced pressure,
Colorless transparent solid organopolysiloxane (A-1) 6
4.7 g was obtained. This colorless transparent solid has Mn = 2,30
0, Mw = 3,820, glass transition point 106 ° C., softening point 142 ° C., epoxy equivalent 680 (g / equivalent),
^{By 29} Si-nuclear magnetic resonance spectrum analysis, it was confirmed to be an organopolysiloxane (A-1) having a 3-glycidoxypropyl group represented by the following formula. (PhSiO _3/2 ) _0.8 (CpSiO _3/2 )
_0.2 [In the formula, Ph represents a phenyl group and Cp represents a 3-glycidoxypropyl group]

Reference Example 6 (Preparation of raw material solution for powder coating material) A thermosetting acrylic resin (B-1) obtained in Reference Example 1 was placed in a reaction vessel equipped with a stirrer, a thermometer, a condenser and a nitrogen gas inlet. ) Solution (B'-1) 1430 parts, methyl ethyl ketone 1200 parts, isopropyl alcohol 7
"Toray Silicone SH-6018" was charged as organopolysiloxane (A) while stirring 00 parts.
(A silanol group-containing organopolysiloxane having a cyclic siloxane structure, manufactured by Toray Silicone Co., Ltd.) 2
50 parts, 175 parts of dodecanedioic acid as a curing agent (C), 4 parts of butyl carbitol as a high boiling point solvent (D1), 5 parts of benzoin, "Acronal 4F" (Germany BA
A powder coating raw material solution (S-1) is prepared by adding 5 parts of a flow control agent manufactured by SF Co., Ltd., and thoroughly stirring and mixing until the raw material is uniformly dissolved and the solution becomes transparent. did. Property values of the resulting powder coating material solution (S-1) are shown in Table 4 (1).

Reference Example 7 (Preparation of powder coating raw material solution in which pigment is dispersed) Thermosetting acrylic resin solution (B'-) obtained in Reference Example 1
1) In 1430 parts, as a pigment, "Taipec CR-9
0 "(Rutile titanium oxide manufactured by Ishihara Sangyo Co., Ltd.) 43
A white pigment-dispersed resin solution was prepared by adding 0 part and dispersing with a sand mill.

Next, the prepared white pigment-dispersed resin solution, 1200 parts of methyl ethyl ketone and 700 parts of isopropanol were charged into a reaction vessel equipped with a stirrer, a thermometer, a condenser and a nitrogen gas inlet, and the organopolysiloxane was stirred. (A) "Tore Silicone S
H-6018 "250 parts, dodecanedioic acid 175 parts as a curing agent (B), butyl carbitol 5 parts as a high boiling point solvent (D1), benzoin 5 parts and" acronal 4 ".
By adding 5 parts of “F” and further stirring sufficiently, a colored powder coating material solution (S-2) was obtained. This solution (S-
Property values of 2) are shown in Table 2 (1).

Reference Example 8 (same as above) Thermosetting polyester resin (B-
1) 854 parts were crushed and this was dissolved in 1000 parts of ethyl acetate. Next, as a pigment, "Taipec CR-9
430 parts of "0" was added and the pigment was dispersed with a sand mill to prepare a white pigment dispersion solution.

Further, to this solution, the kind and amount of organopolysiloxane (A), curing agent (C), high boiling point solvent (D1) and various additives shown in Table 2 (2) and 1700 parts of ethyl acetate were added. By adding and stirring well,
A colored powder coating material solution (S-3) was obtained. Second property value
It shows in Table (2).

Reference Example 9 (same as above) Thermosetting polyester resin (B), organopolysiloxane (A), curing agent (C), high boiling point solvent (D1), and various additives and organic solvent (D) 2 A colored powder coating material solution (S-4) was obtained in the same manner as in Reference Example 7 except that the changes were made as shown in Table (2). Property values are shown in Table 2 (2).

[0166]

[Table 3]

[0167]

[Table 4]

<< Footnote in Table 2 >>"SH-6018" ...
.. "Toray Silicone S" manufactured by Toray Silicone Co., Ltd.
H-6018 "A silanol group-containing compound having a cyclic siloxane structure represented by the following structural formula (molecular weight: about 1,
600, hydroxyl group content 5.5% by weight)

(RSiO _3/2 ) ₄ (R (OH) SiO
_2/2 ) ₂ (SiO _4/2 ) _c (wherein R represents an alkyl group or a phenyl group)

"B1530" ... "VESTAGON B1530" manufactured by Huls in Germany (blocked isocyanate compound in the form of a block of isophorone diisocyanate nurate with ε-caprolactam) "BF1540" .. "VEST" manufactured by Huls in Germany
AGON BF1540 "(blocked isocyanate compound in the form of isophorone diisocyanate self-blocked by uretdione bond)

“XL-552” ... Acid amide compound “PRIMIB XL-552” “CR-90” manufactured by Ems AG of Switzerland .... Rutile titanium oxide manufactured by Ishihara Sangyo Co., Ltd. Taipaque CR-90 "" Acronal 4F "...- Fluidity regulator DPGME, manufactured by BASF, Germany. Dipropylene glycol monoethyl ether" Solvesso 150 ". .... Aromatic hydrocarbon-containing mixed hydrocarbon solvent manufactured by Exxon Corporation, USA

Reference Example 10 (Organopolysiloxane (A) and thermosetting resin (B) in organic solvent (S-5)
Preparation Example of Thermosetting Polyester Resin (B-
2) 854 parts and 300 parts of "SH-6018" were added to 1800 parts of ethyl acetate, and the mixture was stirred and mixed at room temperature to obtain an organic solvent solution of organopolysiloxane (A) and thermosetting polyester resin (B-2). (S-5) (nonvolatile matter 39.1%) was prepared.

Example 1 (Production of Powder Coating Material of the Present Invention by Spray Drying Method) An explosion-proof vertical descending cocurrent spray drying apparatus equipped with a solvent recovery device, and a powder using a two-fluid nozzle method as a spraying method. Body paint was produced. The atomizing gas pressure was set to 0.3 MPa, nitrogen gas was used as the heat source gas, and the raw material solution and the heat source gas were brought into contact with each other in a vertically descending cocurrent manner. The temperature of the heat source gas was set to 45 ° C. Powder coating raw material solution (S
-1) was sprayed into the spray drying device at a supply rate of 1 kg / hr, and the particles of the powder coating material dried in the device were collected by a cyclone to obtain a powder coating material having an average particle diameter of 17 μm. Most of the particles had a spherical shape. The nonvolatile content of the obtained powder coating material was 99.4%, and the content of butyl carbitol, which is a high boiling point solvent (D1), was measured and found to be 0.35% by weight.

Examples 2 to 4 (same as above) The powder coating material raw material solutions (S-2) to (S-4) were used in place of the powder coating material raw material solution (S-1) to prepare a preliminary powder coating material solution. The heating temperature and the temperature of the heat source gas are shown in Table 3 (1),
Powder coatings (P-2) to (P-4) were obtained in the same manner as in Example 1 except that the changes were made as shown in (2). Property values of the obtained powder coating material are also shown in Table 3 (1) and (2).

[0175]

[Table 5]

[0176]

[Table 6]

Example 5 The organic solvent solution of the organopolysiloxane (A) obtained in Reference Example 10 and the thermosetting polyester resin (B-2) was spray dried in the same manner as in Example 3. 1154 parts of the obtained solid matter was crushed to obtain "Vestagon B1530".
(Block isocyanate compound manufactured by Huls in Germany) 103 parts, "Vestagon BF1540" (block isocyanate compound manufactured by Huls in Germany)
43 copies, "Taipec CR-90" (Ishihara Sangyo Co., Ltd.)
Rutile type titanium oxide) 430 parts, benzoin 5
And 5 parts of "Acronal 4F" (fluid control agent manufactured by BASF, Germany), and "Henschel mixer" (Driving render manufactured by Mitsui Miike Kakoki Co., Ltd.)
Then, after mixing, "MP-2015" (US APV
The mixture was heated and kneaded by a twin-screw extrusion kneader manufactured by Chemical Machinery. The kneaded product thus obtained is pulverized and classified to obtain a powder coating material having an average particle size of 22 μm (P
-5) was obtained.

Comparative Reference Example 1 (Same as above) Thermosetting polyester resin (B-
2) 854 parts were crushed and Torre Silicone SH-60
18 "300 parts," Vestagon B1530 "(blocked isocyanate compound manufactured by Hüls, Germany) 1
03 parts, "Vestagon BF1540" (block isocyanate compound manufactured by Hüls, Germany) 43 parts,
430 parts of "Taipec CR-90" (rutile titanium oxide manufactured by Ishihara Sangyo Co., Ltd.), 5 parts of benzoin, and 5 parts of "Acronal 4F" (fluidity adjusting agent manufactured by BASF Germany) were added. The mixture was mixed with a "Henschel mixer" (Dry blender manufactured by Mitsui Miike Kakoki Co., Ltd.), and then heated and kneaded by "MP-2015" (a twin-screw extrusion kneader manufactured by APV Chemical Machinery, USA). The obtained kneaded product was pulverized and classified to obtain a powder coating material (P-6) having an average particle diameter of 25 μm.

Example 6 (Properties of cured coating film of powder coating material produced by the production method of the present invention) A white alkyd melamine solvent-based coating material having a thickness of 30 μm is formed on a zinc phosphate-treated steel sheet having a thickness of 0.8 mm. Spray coating as above and baking and curing at 140 ° C for 30 minutes,
On top of that, 60 parts of the powder coating material (P-1) obtained in Example 1 was added.
Electrostatic coating was performed so that the film thickness was μm. A coated plate was obtained by baking and curing the coated test plate at 160 ° C. for 20 minutes. The evaluation results of the powder coating and the obtained cured coating film are shown in Table 4 (1).

Example 7 (same as above) The powder coating material (P-2) obtained in Example 2 was electrostatically coated on a 0.8 mm thick zinc phosphate-treated steel sheet to a film thickness of 60 μm. A coated plate was obtained by baking and curing the coated test plate at 160 ° C. for 20 minutes. The properties of the obtained cured coating film are shown in Table 4 (1).

Examples 8 to 10 (same as above) Example 7 except that the powder coating used and the baking and curing temperature were changed as shown in Table 4 (1) and (2).
A coated plate was obtained in the same manner as. The properties of the obtained cured coating film are shown in Table 4 (1) and (2).

Comparative Example 1 The procedure of Example 7 was repeated except that the powder coating material used (P-6) obtained in Comparative Reference Example 1 was used.
I got a coated plate. The evaluation results of the powder coating material and the obtained cured coating film are shown in Table 4 (2).

[0183]

[Table 7]

[0184]

[Table 8]

<< Footnotes in Table 4 >> Smoothness ... The smoothness of the coating film was visually evaluated. Evaluation 5: Evaluation of smooth and smooth coating surface 4: Evaluation of small rounds 3: Evaluation of large rounds 2: Evaluation of large rounds with many fine dust skin Evaluation 1: Large rounds When there is a large amount of fine dusty skin and the appearance of the coating film is greatly impaired

Vividness ... A coating plate was placed under the light of a fluorescent lamp, and the image quality of the fluorescent lamp reflected on the surface of the coating film was judged. Evaluation 5: The border of the image is clear and there is no line bleeding 4: The border is slightly blurred 3: The border is blurred 2: The border is difficult to discriminate 1: The border is indistinguishable

Presence / absence of coating film defect ....
Number of coating defects such as dents and pinholes (Coating plate 1
(Per 00 square cm). Evaluation ◎: 0 evaluation ○: 1-2 evaluation Δ: 3-10 evaluation ×:> 10

Coating film gloss: Measured from the specular gloss of JIS-K5400.

Weather resistance: 1500 using a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd.)
The gloss retention (%) of the coating film after the time exposure was indicated.
The higher this value, the better the weather resistance.

· Storage stability ······················· produced paint was left in a thermostat at 30 ° C. for 2 weeks, and then judged again by coating workability when the paint was sprayed. Evaluation ◯: No problem evaluated Δ: Difficulty in spraying due to the formation of some aggregates ×: Impossible to spray

[0191]

As has been made clear by the detailed description above,
The powder coating composition and the coating film forming method according to the present invention are particularly excellent in the weather resistance of the coating film and the storage stability of the coating material, and in addition, are excellent in smoothness and the like. The manifestation of various effects is observed.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 183/04 C09D 183/04 183/06 183/06 F term (reference) 4J038 CD091 CD101 CD111 CD121 CD131 CG001 CG141 DB061 DD001 DD051 DL032 DL052 DL131 GA03 GA06 GA07 GA09 GA11 GA15 KA03 KA06 MA02 NA01 NA03 NA23 NA26 PA02

Claims (10)

[Claims] 1. An organopolysiloxane (A) having a curing reactive group, a thermosetting resin (B), a curing agent (C) capable of reacting with the thermosetting resin (B), and an organic solvent (D). A powder coating material obtained by spray drying an organic solvent solution containing. 2. An organopolysiloxane (A) having a curing reactive group and a thermosetting resin (B) or a curing agent (C).
And an organic solvent solution containing an organic solvent (D) are spray-dried to obtain an organopolysiloxane (A) and a thermosetting resin (B) or a hardener (C) powder mixture as an essential component Powder coating obtained by using as. 3. An average particle size of 5 to 50 μm and an average circularity of 0.
The powder coating material according to claim 1 or 2, which is 9 or more. 4. The thermosetting resin (B) is a thermosetting resin having a curing reactive group capable of reacting with the curing reactive group of the organopolysiloxane (A). Powder coating according to. 5. The powder coating composition according to claim 4, wherein the thermosetting resin (B) is a thermosetting resin modified with the organopolysiloxane (A). 6. The powder coating composition has a boiling point of 150 at normal pressure.
The high boiling point solvent (D1) which is ~ 300 ° C is 0.005-2
The powder coating material according to any one of claims 1 to 5, which is a powder coating material containing wt%. 7. The curing reactive group of the organopolysiloxane (A) is at least one selected from the group consisting of a hydroxyl group, a silanol group and an epoxy group.
Powder coating according to any one of 1. 8. The thermosetting resin (B) is an acrylic resin,
The powder coating material according to any one of claims 1 to 7, which is at least one selected from the group consisting of a polyester resin and a fluororesin. 9. A coating film forming method for forming a single-layer or multi-layer coating film on an object to be coated, characterized in that the powder coating material according to any one of claims 1 to 8 is used. , Coating film forming method. 10. A coated article having a coating film formed by the method for forming a coating film according to claim 9.