JP2003055613A - Designable thermosetting power coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting powder coating which is excellent in continuous coating and can be used for recoating to give a mat film that is excellent in appearance stability and brings soft touch and high quality as felt in a suede. SOLUTION: The designable thermosetting powder coating comprises being obtained by spray drying an organic solvent solution comprising a thermosetting resin, a curing agent and a resin particle having a three-dimensional bridge structure as the indispensable film-forming components, wherein the thermosetting powder coating has an average particle size of 5-100 μm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel and useful design thermosetting powder coating material. More specifically,
A thermosetting powder coating having an average particle size of 5 to 100 μm, which has excellent fluidity of the powder coating, workability of electrostatic coating, and excellent scratch resistance, as well as visual and tactile sensations. The present invention relates to a design thermosetting powder coating material that forms a design coating film.

[0002]

2. Description of the Related Art Powder coatings are widely used in general metal coatings as environmentally friendly coatings that do not volatilize organic solvents into the atmosphere during coating. Among them, thermosetting powder coating materials have been recognized for their excellent coating film performance and have been applied to various applications.

In the field of large-scale coating industry such as automobile industry and home appliance industry, powder coating which has not been applied is collected from the viewpoint of resource saving and reused for coating (hereinafter referred to as "recoating"). However, there is a strong demand for the development of powder coatings that maintain stable quality. In addition, in recent years, with the trend toward high-grade home appliances, there is an increasing demand for a paint film that has a matt, high-grade visual design such as suede tone and a soft tactile sensation when touched by hand. There is. Correspondingly, in solvent-type paints, a method of adding elastic or non-elastic resin particles to impart a design property to a coating film has been widely used.

However, in thermosetting powder coating materials, a method of making a coating material by melt-kneading has been widely adopted, and since the shape of the resin particles changes during kneading and pulverization in the process, the originally intended suede tone or the like is obtained. It has problems such as the failure to obtain a high-quality coating film.

Further, in JP-A-4-323272, a thermosetting powder coating material and resin particles are dry-blended,
Although coating and curing methods have been attempted, coating films with high design properties such as suede tone can be obtained, but on the other hand, since the charging characteristics of thermosetting powder coating particles and resin particles are different,
The content of the resin particles in the coating film is liable to change, a stable appearance cannot be obtained, and the initial coating film appearance cannot be obtained even when "repainted".

[0006]

DISCLOSURE OF THE INVENTION The present inventors solved the various problems in the prior art described above and started earnest research to obtain highly practical design powder coating materials and coated objects. The problem to be solved by the present invention is to obtain a high-grade matte coating film such as suede tone, which is excellent in continuous coating property of powder coating material and has excellent appearance stability at the time of re-coating, and is soft in touch. To provide a thermosetting powder coating material.

[0007]

Means for Solving the Problems The present inventors have earnestly studied to solve the above-mentioned problems, and as a result, as a coating film forming component, a thermosetting resin (A) and a curing agent (B) were used. And a coating film formed by using a thermosetting powder coating material obtained by spray drying an organic solvent solution containing resin particles (C) having a three-dimensional crosslinked structure as an essential component, The inventors have found that the mechanical properties of the powder coating are particularly excellent and that the repaintability of the powder coating is also excellent, and the present invention has been completed here.

That is, according to the present invention, an organic solvent containing a thermosetting resin (A), a curing agent (B), and resin particles (C) having a three-dimensional crosslinked structure as essential components as coating film forming components. It is intended to provide a design thermosetting powder coating material having an average particle diameter of 5 to 100 μm, which is obtained by spray-drying a solution.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be specifically described below. The designable thermosetting powder coating material of the present invention comprises an organic solvent solution containing a thermosetting resin (A), a curing agent (B), and resin particles (C) having a three-dimensional crosslinked structure as essential components. It is obtained by spray drying, and is characterized by having an average particle diameter of 5 to 100 μm. Considering the smoothness at the time of thin film, more preferably 1
It is 0 to 50 μm. The average particle diameter means the volume average median diameter, and can be measured, for example, with a laser diffraction particle size analyzer (SALD-2000) manufactured by Shimadzu Corporation.

The powder coating material of the present invention is essentially spherical and its average circularity is preferably 0.9 or more. By using a spherical powder paint, the paint fluidity and repaintability 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 circularity and the average circularity referred to here are one of the particle shape indexes representing the unevenness of the surface of the particles,
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.

Next, spray drying will be described. The powder coating material of the present invention is an organic solvent solution containing a coating film forming component (hereinafter,
Described as a powder coating material solution. ) Is obtained by spray drying. 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-mentioned spray dryer for contacting the sprayed powder coating raw material solution with the heat source gas to volatilize the organic solvent, the method of contacting the powder coating raw material solution and 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.

Regarding the method of spraying the raw material solution for powder coating,
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 according to 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.

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, 30 ° C or higher is preferable, and 40 ° C or higher is more preferable. Usually, the temperature of the heat source gas is 30 to 160 ° C, preferably 40 to 13 ° C.
It is appropriately determined within the range of 0 ° C.

The flow rate of the heat source gas and the supply rate of the powder coating material solution may be appropriately adjusted according to the intended particle size under the condition that the non-volatile content of the obtained particles is 99% by weight or more. . The pressure inside the apparatus is not particularly limited, and may be normal pressure, reduced pressure, or increased pressure.

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.

Further, in order to evaporate the solvent more efficiently, the powder coating material raw 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 thus obtained can be used as it is as a powder coating, but it may be secondarily dried by another drying method such as vacuum drying, if necessary. In that case, in order to prevent gelation of the powder coating material, it is desirable that the secondary drying be performed at a temperature of about 70 ° C. or lower.

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. A solvent that does not dissolve both the thermosetting resin and the curing agent can be used as long as it does not impair the storage stability of the powder coating material raw material solution.

Next, the thermosetting resin which is a film forming component will be described. As the thermosetting resin (A), any of the resins usually used in powder coatings such as acrylic resin, polyester resin, and epoxy resin can be used, and among them, acrylic resin and polyester resin are preferable. Also,
As the thermosetting resin (A), a resin having a softening point in the range of 80 to 150 ° C. is particularly preferable because a powder coating having excellent storage stability during storage and a good balance of coating film appearance can be obtained. .

When the thermosetting resin (A) is an acrylic resin, a known and conventional method can be applied to prepare the base acrylic resin, but a vinyl monomer containing a curing reactive group is further required. Accordingly, a method of using other copolymerizable vinyl monomers and polymerizing each of these monomers in an organic solvent is recommended because it is the simplest method. As the polymerization initiator and solvent used at that time, known and conventional ones can be used as they are.

Examples of the curing-reactive group of the thermosetting resin (A) 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. Since it is easy, 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 coating appearance.

If only typical examples of 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 also be used, if necessary, but only representative examples of such other copolymerizable monomers are given. For example, various acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert.
Various methacrylic acid esters such as butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate;

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 and 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 the various curing-reactive group-containing vinyl monomers as exemplified above is appropriately 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.

The number average molecular weight of the thermosetting acrylic resin is appropriately in the range of 1,000 to 20,000, and preferably in the range of 1,500 to 15,000. preferable. 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 polyester resin used as the thermosetting resin (A) is not particularly limited, and various known and conventional methods can be used, but polyhydric alcohol and polybasic acid are condensed. It can be manufactured by a method. 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 of the polyester resin used as the thermosetting resin (A), various known and commonly used compounds can be used. Use of these polyhydric alcohol and polybasic acid A polyester resin having a carboxyl group and / or a hydroxyl group can be obtained by adjusting the amount.

First of all, only typical examples of the above-mentioned polyhydric alcohols will be exemplified. Ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol. , 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, triethylene glycol, bis-hydroxyethyl terephthalate, cyclohexanedimethanol, octanediol, diethylpropanediol, butylethylpropanediol, 2-methyl-1. , 3-propanediol, 2,2,4-trimethylpentanediol, hydrogenated bisphenol A, ethylene oxide adduct of hydrogenated bisphenol A, propylene oxide adduct of hydrogenated bisphenol A, Trimethylol ethane, trimethylol propane, glycerine, pentaerythritol, tris-hydroxyethyl isocyanurate, and the like hydroxypivalic valyl hydroxy pivalate.

On the other hand, if only representative examples of the above-mentioned polybasic acids are given, 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 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 polyester resin, a compound having both a carboxyl group and a hydroxyl group in one molecule, such as dimethanolpropionic acid and hydroxypivalate; "Cadura E10" (manufactured by Dutch Shell company, branched Monoepoxy compounds such as glycidyl ester of aliphatic carboxylic acid); such as methanol, propanol, butanol, benzyl alcohol,
Various monohydric alcohols; various monohydric basic acids such as benzoic acid and p-tert-butylbenzoic acid; various fatty acids such as castor oil fatty acid, coconut oil fatty acid, soybean oil fatty acid and the like can also be used. it can.

As the polyester resin obtained by using various polyhydric alcohols, polybasic acids and other raw materials as mentioned above, the total of the acid value and the hydroxyl value is 10 to 250, among others. (MgKOH / g; the same applies hereinafter), and it is desirable to use a form having a number average molecular weight of 500 to 10,000.

When the sum of the acid value and the hydroxyl value is within the above range, a coating film excellent in 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 polyester resin 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 (A) is not particularly limited, but examples thereof include epoxy resins such as polyglycidyl ether of bisphenol-A.

Next, the curing agent (B) will be described. The curing agent (B) used in the present invention is appropriately selected from those which are usually used for powder coatings, depending on the type of the curing reactive group of the thermosetting resin (A). Used.

As the curing agent (B), when the curing-reactive group of the thermosetting resin (A) is an epoxy group, succinic acid, glutaric acid, Adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecane dicarboxylic acid, eicosane dicarboxylic 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 acid anhydrides thereof are available. Among them, since they are excellent in coating film physical properties and storage stability, they are aliphatic dibases. An acid is preferred, and dodecanedicarboxylic acid is particularly preferred because of its excellent coating film properties.

Further, when the curing reactive group of the thermosetting resin (A) is a carboxyl group, only representative examples of the curing agent (B) will be given. If 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; Epoxy compound having such isocyanurate ring structure triglycidyl isocyanurate, hydroxy amides such as β- hydroxyalkyl amides.

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

As the polyblock polyisocyanate compound, only representative ones are exemplified. Various aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; xylylene diisocyanate and isophorone diisocyanate, Various cyclic aliphatic diisocyanates; organic diisocyanates such as various aromatic diisocyanates such as tolylene diisocyanate and 4,4′-diphenylmethane diisocyanate, or these organic diisocyanates, polyhydric alcohols, low molecular weight polyester resins ( (Polyester polyol) or an adduct with water or the like is blocked with a known conventional blocking agent having active hydrogen such as caprolactam or oxime. It is of the form to be,

Further, the above-mentioned polymers of organic diisocyanates (including isocyanurate type polyisocyanate compounds) as well as various polyisocyanate compounds such as isocyanate biuret form a known and commonly used block. 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.

Specific examples of such aminoplasts include only hexamethoxymethylolmelamine, hexabutyletherified methylolmelamine, methylbutyl mixed etherified methylolmelamine, methyletherified methylolmelamine, and 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 (B) may be used alone or in combination of two or more kinds. The compounding amount of the curing reactive group of the thermosetting resin (A) and the curing agent (B) is such that the equivalent ratio of the curing reactive group of the thermosetting resin (A) to the equivalent amount of the curing agent (B) is 2. It is preferably between 0 and 0.5.

Next, the resin particles (C) having a three-dimensional crosslinked structure will be described. The resin particles having three-dimensional cross-linking used in the present invention, acrylic resin particles, polystyrene resin particles, polyester resin particles,
Examples thereof include silicone resin particles, melamine resin particles, phenol resin particles, polyurethane polyurea particles and the like. Above all, it is preferable to use polyurethane polyurea resin particles.

It is necessary that these resin particles have a three-dimensional crosslinked structure inside the resin. Due to the three-dimensional crosslinked structure, the particles do not dissolve even in the presence of the organic solvent used in the present invention, or the particle shape is Does not change significantly,
It is possible to give the coating film good designability. The average particle size of the resin particles is preferably 0.1 to 100 μm, more preferably 1 to 50 μm. These resin particles may or may not be pigmented.

Polyurethane polyurea particles will be described below as typical resin particles. Polyurethane polyurea particles are obtained from polyisocyanate compounds, polyhydroxy compounds and polyamine compounds. As an example of its production, first, a polyisocyanate compound is blended in such a manner that the polyhydroxy compound is in excess, and the mixture is uniformly mixed to prepare an organic phase. At this time, if necessary,
A mill base containing a pigment or an organic solvent may be added for the purpose of adjusting the viscosity. This organic phase is finely dispersed in an aqueous phase, and an equimolar amount or less of polyamine is added to a stoichiometrically excess isocyanate group in the organic phase to cause a urea reaction at the particle interface. By carrying out the urethanization reaction inside, a dispersion of polyurethane polyurea particles having a three-dimensional crosslinked structure is obtained.

The desired polyurethane polyurea particles can be obtained by removing water (including an organic solvent when an organic solvent is contained) from this dispersion by a method such as vacuum drying. In producing the thermosetting powder coating material of the present invention, the resin particles having a three-dimensional crosslinked structure such as the above-mentioned isolated polyurethane polyurea particles are mixed in the powder coating material solution, but in some cases, It is also possible to mix the resin particles in the raw material solution as they are without isolation.

As the polyisocyanate compound, any of those known per se may be used, but of these, only typical ones are tolylene diisocyanate. , Hydrogenated tolylene diisocyanate, diphenylmethane-4,
4'-diisocyanate, hydrogenated diphenylmethane-4,
4'-diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, 1,3-bis (α, α-dimethylisocyanate methyl) benzene, cyclohexyl-1 , 4-
Aliphatic, aromatic or cycloaliphatic di- or triisocyanate monomers such as diisocyanate, oxadiazinetrione diisocyanate, isophorone diisocyanate or triphenylmethane diisocyanate;

Alternatively, various modified polyisocyanates such as tri- or higher functional polyisocyanurate type polyisocyanates or burette type polyisocyanates based on these various monomers;

Furthermore, at least one of the various monomers and modified polyisocyanates listed above and one of various polyhydroxy compounds such as polyhydric alcohol, polyester polyol, polycarbonate polyol, polybutadiene polyol or polypentadiene polyol. Examples thereof include urethane-modified polyisocyanate prepolymers having an isocyanate group at the end, which are obtained by the urethanization reaction with the above, and these may be used alone or in combination of two or more kinds.

In order for the obtained polyurethane polyurea particles to be particularly excellent in toughness, the polyisocyanate compound has a number average molecular weight of 200 to 10,000.
It is desirable that it is within the range of 0, preferably within the range of 300 to 7,000, and more preferably within the range of 500 to 5,000.

Further, the urethane-modified polyisocyanate compound obtained by the reaction of polycaprolactone polyester polyol and diisocyanate is contained in an amount of 10% by weight or more, preferably, in all polyisocyanate compounds.
It is also preferable to contain 20% by weight or more in order to improve the toughness of the resin particles.

In designing the polyisocyanate compound, in consideration of weather resistance and the like, aliphatic and / or alicyclic system is recommended as the type of isocyanate monomer unit.

On the other hand, the polyhydroxy compound as a component constituting the organic phase together with the polyisocyanate compound compensates for the lack of internal cross-linking due to the formation of the wall portion of the polymer particles, and further improves the mechanical strength of the particles. Since it is an extremely important component, any of those known per se as such polyhydroxy compounds can be used, but among them, particularly typical ones are as follows. , Which belongs to one of the groups.

A) ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-bis (hydroxytyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, hydroxypivalyl hydroxypivalate, trimethylolethane, trimethylolpropane, 2,2,4-trimethyl-1,3-pentanediol, glycerin , Hexanetriol, tris (2-hydroxyethyl) isocyanurate or pentahydric alcohols such as pentaerythritol;

B) polyether glycols such as polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene tetramethylene glycol, polyoxypropylene tetramethylene glycol or polyoxyethylene polyoxypropylene polyoxytetramethylene glycol;

C) by ring-opening polymerization of various polyhydric alcohols such as those listed above with ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether or allyl glycidyl ether. Modified polyether polyols obtained;

D) Polyester polyols obtained by cocondensation of at least one of the various polyhydric alcohols listed above with polyhydric carboxylic acids. To give only representative polyvalent carboxylic acids mentioned here, succinic acid, adipic acid, sebacic acid, azelaic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, fumaric acid, citracone. Acid, itaconic acid, glutaconic acid, 1,2,5-hexanetricarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2,
4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid or 2,5,7-naphthalenetricarboxylic acid.

E) Obtained by polycondensation reaction of at least one of various polyhydric alcohols as listed above with various lactones such as ε-caprolactone, δ-valerolactone or 3-methyl-δ-valerolactone. Lactone-based polyester polyols, or lactone-modified polyester polyols obtained by polycondensation reaction of various polyhydric alcohols and polycarboxylic acids with various lactones as listed above, respectively. ;

F) Bisphenol A type epoxy compound,
Hydrogenated bisphenol A type epoxy compound, monovalent and /
Epoxy modified polyester polyols obtained by using at least one of various epoxy compounds such as glycidyl ether of polyhydric alcohol or glycidyl ester of monobasic acid and / or polybasic acid at the time of preparing the polyester polyol. ;Moreover,

G) polyester polyamide polyol,
Examples thereof include polycarbonate polyol, polybutadiene polyol, polypentadiene polyol, castor oil, castor oil derivative, hydrogenated castor oil, hydrogenated castor oil derivative, and hydroxyl group-containing acrylic copolymer.

The polyhydroxy compounds as shown in these (a) to (g) may be used alone or in combination of two or more, but the heat average molecular weight thereof is preferably 200 to. It is suitable for sufficient cross-linking inside the resin particles that the amount is in the range of 10,000, more preferably in the range of 300 to 7,000, and further preferably in the range of 500 to 5,000. is there.

Further, in order to obtain tough resin particles, it is preferable to use a polyester polyol, which is obtained by a polycondensation reaction with a lactone such as ε-caprolactone, δ-valerolactone or 3-methyl-δ-valerolactone. It is preferable to use the lactone type polyester polyols.

The mixing ratio of the isocyanate group equivalent of the polyisocyanate compound and the hydroxyl group equivalent of the polyhydroxy compound is preferably 1: 0.1 to 1: 0.9, and 1: 0.1 to 1: 0. 8 is more preferable, and still more preferably in the range of 1: 0.1 to 1: 0.7.

That is, in the case of completely urethanizing these mixtures, it is necessary to make the composition such that the mixture becomes a gel and the fluidity is not obtained even by heating or diluting the true solvent. Due to the design of the three-dimensional urethanization reaction inside the resin particles, the polyisocyanate compound and / or polyhydroxy compound having a functionality of 3 or more are contained in the total amount of the polyisocyanate compound and the polyhydroxy compound contained in the organic phase, By containing 0.1 mol% or more, preferably 0.2 mol% or more, and more preferably 0.3 mol% or more, a good three-dimensional crosslinked state inside the resin particles can be obtained.

Known and commonly used organic pigments, inorganic pigments, and extender pigments are used as the pigments to be included if necessary. Of these, only typical ones are listed below. Insoluble azo pigments such as benzine yellow, Hansa yellow or lake red 4R; lake red C, carmine 6B or bordeaux 10
Soluble azo pigments such as;

Copper phthalocyanine pigments such as phthalocyanine blue or phthalocyanine green; basic dyed lakes such as rhodamine lake or methyl violet lake; acid dyed lakes such as quinoline lake or fast sky blue; mordant pigments such as alizarin lake;

Anthraquinone-based pigments such as thioindigo-based or perinone-based vat dyes; Shincasia Red B
Quinacridone pigments such as; dioxazine pigments such as dioxazine and violet; condensed azo pigments such as chromophthal, and the like; inorganic pigments include chromate salts such as yellow lead, zinc chromate or molybdate orange;

Ferrocyan compounds such as dark blue; metal oxides such as titanium white, zinc white, mapico yellow, iron black, red iron oxide or chrome oxide green; cadmium yellow,
Sulfide selenides such as cadmium red or mercury sulfide; sulfates such as barium sulfate or lead sulfate; silicates such as calcium silicate or ultramarine; carbonates such as calcium carbonate or magnesium carbonate; cobalt violet or manganese purple Phosphate; aluminum powder,
Metal powder such as gold powder, silver powder or brass powder; or pearl pigment, etc.

As extender pigments, precipitated barium sulfate,
Barium carbonate, powder, gypsum, white alumina, clay,
Silica, silica white, talc, calcium silicate or precipitated magnesium carbonate and the like, carbon black not belonging to both inorganic pigments and organic pigments, of course,
Can be used.

These pigments are used as a mill base after being uniformly kneaded with one or more of the above-mentioned polyhydroxy compounds, but the pigments may be chemically surfaced before use or during kneading, if necessary. It is also possible to combine two or more kinds of pigments for treatment or kneading, or to use additives such as a pigment dispersant and a color separation preventing agent which are well known and commonly used in the coating industry and the printing ink industry.

The kneading is carried out by using a known and commonly used disperser such as a ball mill, a pebble mill, a sand mill, an attritor, a roll mill, a high speed impeller disperser or a high speed stone mill. It is also possible to adjust the viscosity of the kneading system by adding active organic solvents. Suitable organic solvents are aromatic or aliphatic hydrocarbons, esters, ethers, ketones, among which benzene, toluene, xylene, cyclohexane, methylcyclohexane, diphenyl ether or mineral spirits are suitable. There is.

The ratio of the resin to the pigment in the mill-base kneading step is preferably 1 to 900 parts by weight of the pigment, more preferably 2 to 800 parts by weight, and still more preferably 5 to 100 parts by weight of the resin solid content. It is in the range of 500 parts by weight.

The mill base thus obtained and the polyhydroxy compound or the polyisocyanate compound are blended within the various ranges as described above and uniformly mixed to form an organic phase. The pigment contained in the organic phase is The ratio is preferably 0.5 to 200 parts by weight, more preferably 1 to 150 parts by weight, and even more preferably 2 to 100 parts by weight with respect to 100 parts by weight of the total resin solid content.

This organic phase is finely dispersed in an aqueous phase, and 0.2 to 1.0 equivalent of polyamine, and preferably 1 to 10 equivalents of polyamine per equivalent of excess isocyanate groups contained in the organic phase.
0.3-1.0 equivalents, more preferably 0.4-0.
9 equivalents were added to carry out the ureation reaction at the particle interface,
Further, by carrying out the urethanization reaction inside the polymer particles, extremely tough pigmented polyurethane polyurea particles can be obtained.

The above-mentioned polyamines are known diamines,
Of the polyamines and mixtures thereof, only the most typical ones are 1,2-
Ethylenediamine, bis- (3-aminopropyl) -amine, hydrazine, hydrazine-2-ethanol, bis- (2-methylaminoethyl) -methylamine, 1,4
-Diaminocyclohexane, 3-amino-1-methylaminopropane, N-hydroxyethylethylenediamine, N-methyl-bis- (3-aminopropyl) -amine, tetraethylenediamine, hexamethylenediamine, 1-aminoethyl-1,2. -Ethylenediamine, bis- (N, N'-aminoethyl) -1,2-ethylenediamine, diethylenetriamine, tetraethylenepentamine, pentaethylenehexamine, phenylenediamine, toluylenediamine, 2,4,6-triaminotoluenthihydro. Chloride, 1,3,8-triaminonaphthalene, isophoronediamine, xylylenediamine, hydrogenated xylylenediamine, 4,4′-diaminodiphenylmethane or hydrogenated 4,4′-diaminodiphenylmethane,

Other examples include derivatives of these polyamine monomers, but from the viewpoint of weather resistance, it is desirable to use aliphatic and / or alicyclic compounds.

The organic phase dispersed in the aqueous phase is itself non-reactive. The viscosity of this hydrophobic organic solvent can be lowered by adding an organic solvent if necessary,
The dispersibility in the water phase can be improved. In this case, the amount of the organic solvent is preferably 50% by weight or less, more preferably 40% by weight or less, still more preferably 30% by weight or less, based on the total organic phase.

Suitable organic solvents are aromatic or aliphatic hydrocarbons, esters, ethers and ketones, among which benzene, toluene, xylene,
Cyclohexane, methylcyclohexane, diphenyl ether or mineral spirits are suitable.

If necessary, these organic solvents may be distilled off during the formation of the polymer particles or after the formation of the polymer particles by a treatment such as heating or reduced pressure. The aqueous phase in which the organic phase is dispersed is polyvinyl alcohol, hydroxyalkyl cellulose, carboxyalkyl cellulose,
One or more kinds selected from various protective colloids such as gum arabic, polyacrylate, polyacrylamide, polyvinylpyrrolidone and ethylene-maleic anhydride copolymer are contained in an amount of 0.2 to 20% by weight.

The aqueous phase may contain 0.2 to 10% by weight of various nonionic, anionic or cationic surfactants.

Inside the polymer particles, positively,
The urethanization reaction is carried out, but as is well known, the urethanization reaction between a hydroxyl group and an isocyanate group is compared with the urethanization reaction with an amino group, especially when the isocyanate group is based on an aliphatic system or an alicyclic system. The reaction speed tends to be slow.

The reactivity between water and isocyanate is extremely slow as compared with the reactivity with hydroxyl group, and the permeation effect of the outer wall formed by the addition of polyamine makes the permeation of water into the inside of the particles negligible. The urethane reaction in the particles can be carried out by raising the reaction temperature and taking time. Furthermore, cobalt naphthenate, zinc naphthenate, stannous chloride, stannic chloride,
Various types such as tetra-n-butyltin, tri-n-butyltin acetate, n-butyltin trichloride, trimethyltin hydroxide, dimethyltin dichloride, dibutyltin diacetate, dibutyltin dilaurate, tin octenoate or potassium oleate. One or more organometallic catalysts are added to the hydrophobic organic phase in an amount of 5 to 10,000 p.
By adding pm, preferably in the range of 10 to 5,000 ppm, tough crosslinked polymer particles can be formed in an extremely short time.

These organometallic catalysts can very effectively accelerate the reaction between the isocyanate group and the hydroxyl group. Adding the above-mentioned organometallic catalyst to the organic phase prior to water dispersion (fine dispersion) increases the viscosity of the organic phase and reduces the dispersibility in the water phase. Since it is not practical, the addition of the organometallic catalyst after the addition of the polyamine causes the organometallic catalyst to be formed because the outer wall of the polymer particles is being formed.
It becomes difficult to be taken into the inside of the polymer particles, and by extension, the effect of accelerating the urethanization reaction inside the polymer particles tends to be reduced. Therefore, when adding the organometallic catalyst, the organic phase is changed to an aqueous phase. Most suitable is during the water dispersion step of dispersing, or between the dispersion step and the middle of the step of adding the polyamine.

The mixing ratio of the thermosetting resin (A) having a three-dimensional crosslinked structure and the curing agent (B) to the resin particles (C) is {(A) + (B)} / (C) solid. It is appropriate that the weight ratio is within the range of 20/80 to 80/20.

Next, the organic solvent used in the present invention will be described. As the organic solvent, thermosetting resin (A) and /
Alternatively, a solvent capable of dissolving the curing agent (B) can be used, and one kind or two or more kinds of solvents may be used in combination, and the thermosetting resin (A) is a resin obtained by solution polymerization. Has
The solvent used in the polymerization of the thermosetting resin (A) can be used as it is as a part or all of the organic solvent.

Further, it is also preferable that the organic solvent contains a high boiling point solvent having a boiling point of 150 to 300 ° C. under normal pressure. By using a high boiling point solvent as a part of the organic solvent, it is possible to obtain a powder coating material which forms a coating film without causing coating film defects such as armpits and pinholes. The high boiling point solvent may be a single component or a mixture of a plurality of components.

As the high boiling point solvent, one having a boiling point of 150 to 250 ° C. under normal pressure is more preferably used. Further, it is particularly preferable that the boiling point at normal pressure is +5 to + 150 ° C. with respect to the temperature when baking and curing the powder coating material of the present invention.

The amount of the high boiling point solvent used is 0.005 to 2 parts, more preferably 0.005 to 1 part, based on 100 parts of the solid content in the powder coating material solution.

When the boiling point of the high boiling point solvent at normal pressure and the amount used are in the above-mentioned ranges, an appropriate amount of the high boiling point solvent remains in the powder coating material of the present invention, resulting in cracks and pinholes during baking and curing. It is possible to prevent the generation of coating film defects.

Specific examples of such high boiling point solvents include only typical ones: alcohols such as n-hexanol, n-octanol, 2-ethylhexanol, cyclohexanol and benzyl alcohol; ethylene glycol, propylene glycol and glycerin. Such as polyhydric alcohols; butyl cellosolve, hexyl cellosolve, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol monobutyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, methyl carbitol, ethyl carbitol, diethylene glycol dimethyl ether, Diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol Glycol ethers, such as dibutyl ether;

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, 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-mentioned high-boiling solvents, 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 to the powder coating material solution is not particularly limited, but for example, the thermosetting resin, which is added in advance as a part of the solvent for polymerizing the thermosetting resin, may be used. A method such as adding after the completion of polymerization or immediately before spray-drying the powder coating material solution is recommended because it is simple and easy.

As the organic solvent, known and commonly used organic solvents can be used in addition to the above high boiling point solvents.

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;

From the viewpoint of improving the drying property of the coating particles during spray drying, the remaining solvent components of the organic solvent except the high boiling point solvent have a boiling point of 100 at normal pressure.
It is preferable that the solvent at a temperature of not more than 0 ° C. accounts for 65 to 100% by weight.

When the curing agent (B) 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 material solution.
It is preferably double or more.

The thermosetting powder coating material of the present invention is obtained by dissolving the thermosetting resin (A) and the curing agent (B) described above in an organic solvent, and further, the resin particles (C) having the three-dimensional crosslinked structure described above. Can be prepared by dispersing the above to prepare a powder coating material raw material solution, and then spray drying the powder coating material raw material solution. Resin particles (C) having a three-dimensional crosslinked structure
As a method for dispersing powder in the powder coating material solution, a known and commonly used mixing and stirring method can be used. In addition, a plurality of colored powder coating material solutions are mixed to adjust the color, a powder coating material solution having a desired color is prepared, and spray-dried to obtain colored resin particles having a three-dimensional crosslinked structure. You may manufacture the thermosetting powder coating material containing (C).

Further, if necessary, other resins such as color pigments, bright pigments, extender pigments, waxes, curing catalysts, antioxidants, leveling agents, defoaming agents, ultraviolet absorbers and other additives. May be added to the powder coating material solution and dissolved or dispersed to form a coating material.

As the other resins which can be added as additives, only representative ones are exemplified, acrylic resin, polyester resin, fluororesin, silicone resin, chlorinated polyethylene, chlorinated polypropylene, petroleum resin. , Various resins such as epoxy resin and chlorinated rubber, and resins other than the thermosetting resin (A) and the curing agent (B). As a curing catalyst,
Depending on the combination of the thermosetting resin (A) and the curing agent (B), known and conventional ones can be used as they are. Furthermore, if necessary, various fibrin derivatives such as nitrocellulose and cellulose acetate butyrate may be used.

Regarding the coating method, the base material to be coated is usually coated by various known methods such as an electrostatic spraying method, a triboelectric coating method, and fluidized dipping. About 120 ~ 250 ℃
It suffices to carry out baking at the temperature of, and in this way a powder coated product 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. The powder coating material may be coated on the object to be coated, and the topcoat coating material may be further coated thereon. It is also preferable that the top coat paint is a transparent powder paint, and the top coat paint is a coloring pigment, an extender pigment, and
Additives such as modifiers, UV absorbers, leveling agents and defoamers can be included.

Here, the article to be coated refers to a base material to which the paint is applied, and more specifically, it is an unpainted metal material such as an unpainted steel plate or an untreated or chemically treated aluminum base material. 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 Examples include various building materials, such as a class; various building interior and exterior materials, such as an aluminum sash.

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.

As described above, the powder coating material of the present invention is applied to various kinds of substrates to be coated by the conventional method, and then baked and dried according to the conventional method. By doing so, it is possible to provide a powder-coated article having a coating film excellent in appearance, designability, and the like.

[0129]

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. The respective raw material components used will be described below in advance.

Among them, the polyisocyanate compound is as follows. That is, "Bernock DN-950" [manufactured by Dainippon Ink and Chemicals, Inc., hexamethylene diisocyanate / adduct type polyisocyanate compound; number average molecular weight = 640, solid content-equivalent isocyanate group content = 16.8%] Although solid content was used, it is abbreviated as PI-1 below. "Burnock DS-980S" (manufactured by the same company, isocyanurate type polyisocyanate compound obtained by using hexamethylene diisocyanate; isocyanate group content =
21.0%); hereinafter, this is abbreviated as PI-2.

Further, 1,000 parts of polycaprolactone polyester triol having a hydroxyl value of 168.5 and 666 parts of isophorone diisocyanate obtained by polycondensation reaction of trimethylolpropane and ε-caprolactone are subjected to urethanization reaction. A polyisocyanate compound having an isocyanate group content of 7.5%, which was obtained as described above, was also used, but this is hereinafter abbreviated as PI-3.

Further, hydrogenated 4,4′-diphenylmethane diisocyanate or 1,6-hexamethylene diisocyanate was also used, but hereinafter abbreviated as H-MDI or HDI, respectively.

Then, as the polyhydroxy compound,
It looks like this: That is, a polyester polyol having a hydroxyl value of 187, which was obtained by the co-condensation of neopentyl glycol and adipic acid, was used, but this is hereinafter abbreviated as PO-1.

A polycaprolactone polyester diol having a hydroxyl value of 187, which is obtained by a polycondensation reaction between neopentyl glycol and ε-caprolactone, was also used, which will be abbreviated as PO-2 hereinafter.

Furthermore, a polycaprolactone polyester polyol having a hydroxyl value of 168.5, which was obtained by a polycondensation reaction of trimethylolpropane and ε-caprolactone, was also used, which is hereinafter abbreviated as PO-3.

Furthermore, trimethylolpropane and ε
A hydroxyl value obtained by polycondensation reaction with caprolactone is 112.2 and a number average molecular weight is 1,50
A polycaprolactone polyester triol of 0 was also used, which is hereinafter abbreviated as PO-4.

Further, the polyamine is as follows. That is, although ethylenediamine was used,
Hereinafter, this is abbreviated as EDA. In addition, 1,6-hexamethylenediamine was also used.
Is abbreviated. Further, isophoronediamine was also used, but hereinafter, this is abbreviated as IPDA.

Reference Example 1 (Preparation Example of Polyurethane Polyurea Particles (C-1)) In a 1 liter flask, "PVA-217" (partial saponification product of polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was added.
While adding 300 parts of a 2% aqueous solution to make this an aqueous phase, in a separate container, 55.7 parts of PI-1 and 9.
3 parts and 30 parts of PO-1 were mixed together to form an organic phase. Using a homomixer at 20 ° C,
7,000 to 7,500 rpm. Then, while stirring the aqueous phase, an organic phase prepared in advance was charged therein, and the mixture was stirred for 1 minute to obtain a dispersion liquid. Then, this dispersion was transferred to another flask, and was stirred at 200 rpm with a paddler type stirring blade. With stirring at 0.1 part of di-n-butyltin dilaurate (DBTDL) was added, and 2 minutes later 21.7 parts of a 50% aqueous solution of HMDA was also added.

After being kept at room temperature (about 25 ° C.) for 2 hours, the temperature was raised to 50 ° C. and the temperature was kept at the same temperature for 1 hour.
The reaction was continued at 0 ° C. for 2 hours to obtain a target suspension of polyurethane polyurea particles (C-1). The suspension was heated and dried under reduced pressure to obtain polyurethane polyurea particles (C-1). The average particle size of this particle is 3
It was 0 μm. Further, the particles are extremely stable without swelling and dissolving in acetone, ethyl acetate, xylene or the like, and further, the particles may be fully filled with a polymer inside. It was confirmed as a result of observation with an electron microscope.

Reference Example 2 (Preparation Example of Polyurethane Polyurea Particles (C-2) Containing Pigment) First, 80 parts of PO-2, “Fast-ogen Super Red” was used.
7093Y "[quinacridone organic pigment manufactured by Dainippon Ink and Chemicals, Inc.] and 25 parts of toluene were mixed and dispersed with a sand grinder for 1 hour to obtain a red mill base. Below, this is MB
It is abbreviated as -1. Then add “P
300 parts of 0.2% aqueous solution of "VA-217" was charged,
At 20 ° C., using a homomixer, from 7,000 to
7,500 rpm. While agitating at 37.5 parts of MB-1, 16 parts of PO-1, in a separate container in advance,
The organic phase, which had been prepared by mixing 30 parts of PI-1 and 20 parts of HDI, was added, and further, DBTDL of 0.
2 parts were added and stirred for 1 minute to obtain a dispersion.

Thereafter, this dispersion was transferred to another flask, and was put to 200 rpm with a paddler type stirring blade. With stirring at 22.3 parts of a 25% aqueous solution of EDA was added. After keeping at room temperature (about 25 ° C) for 2 hours, the temperature is raised to 50 ° C, and the temperature is kept at the same temperature for 1 hour.
The reaction was continued by maintaining the temperature at 2 ° C. for 2 hours to obtain an intended suspension of pigmented red polyurethane polyurea particles (C-2). The suspension was heated and dried under reduced pressure to obtain polyurethane polyurea particles (C-2).
The average particle size of the polymer particles obtained here was 37 μm. Further, the particles did not swell and dissolve in acetone, and therefore, outflow of the red pigment was not observed in acetone.

Example 1 (Preparation example of the designable thermosetting powder coating material (X-1) according to the present invention) FINDIC C-254 (Dainippon Ink and Chemicals Incorporated glycidyl group-containing solid acrylic resin epoxy equivalent 5)
00) 84 parts, dodecanedioic acid (Ube Industries, aliphatic dibasic acid) 16 parts, benzoin 0.5 part, modaflow (Monsanto company leveling agent) 1 part methyl ethyl ketone 1
It was dissolved by heating in 00 parts, 50 parts of isobutanol, and 0.5 parts of Solvesso 100 (Exxon). Then reference example 1
40 parts of the polyurethane polyurea particles (C-1) prepared in 1. were mixed and dispersed in the above resin solution with a mixer.

This organic solvent solution was spray-dried using an explosion-proof vertical descending cocurrent spray dryer equipped with a solvent recovery device, using a rotating disk system as the spray system. The rotation speed of the disk was 15,000 rpm, 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 gas temperature was set to 120 ° C. The powder coating material raw material solution preheated to 60 ° C. is sprayed into the spray drying device at a supply rate of 0.5 kg / hr, and the particles of the powder coating material dried in the device are collected by a cyclone, whereby the present invention is realized. The powder coating material (X-1) of was obtained. The average particle size of the particles is 35 μm
The average circularity was 0.92.

Example 2 (Preparation Example of Design Thermosetting Powder Coating (X-2) According to the Present Invention) Polyurethane polyurea particles (C-2) 40 containing the pigment in Example 1 A powder coating material (X-2) was prepared in the same manner as in Example 1 except that the parts were changed. The average particle size was 40 μm and the average circularity was 0.95.

Example 3 (Preparation example of the designable thermosetting powder coating material (X-3) according to the present invention) FINDIC M-8034 (Dainippon Ink and Chemicals, Inc., hydroxyl group-containing solid polyester resin, hydroxyl value 30)
87 parts, Vestagon B-1530 (manufactured by Degussa, blocked isocyanate compound) 13 parts, benzoin 0.5
Parts, 1 part of Modaflow (a leveling agent manufactured by Monsanto) were dissolved in 150 parts of methyl ethyl ketone and 0.5 parts of Solvesso 150 (Exxon) by heating. Then, as a coloring pigment, carbon black MA100 (manufactured by Mitsubishi Chemical Corporation) 5
After being dispersed in a sand mill, 40 parts of polyurethane polyurea particles (C-1) were mixed and dispersed in the above resin solution with a mixer. This organic solvent solution was spray dried in the same manner as in Example 1. By collecting particles of the powder coating material dried in the apparatus with a cyclone, the powder coating material (X
-3) was obtained. The average particle size of the particles was 30 μm, and the average circularity was 0.95.

Example 4 (Preparation example of the designable thermosetting powder coating material (X-4) according to the present invention) FINDIC M-8961 (manufactured by Dainippon Ink and Chemicals, Inc., carboxylic acid group-containing solid polyester resin, acid value 3)
3) 95 parts, Primid XL552 (manufactured by EMS, hydroxyalkylamide) 5 parts, benzoin 0.5 part, modaflow (Monsanto leveling agent) 1 part, methyl ethyl ketone 150 parts, Solvesso 100 (Exxon)
It was dissolved by heating in 0.5 part. Next, 40 parts of polyurethane polyurea particles (C-2) were mixed and dispersed in the above resin solution with a mixer. This organic solvent solution was spray dried in the same manner as in Example 1. The powder paint particles (X-4) of the present invention were obtained by collecting particles of the powder paint dried in the apparatus with a cyclone. The average particle size of the particles was 40 μm, and the average circularity was 0.95.

Comparative Reference Example 1 (Preparation of Powder Coating (Z-1) by Melting and Kneading Polyurethane Polyurea Particles for Comparison) Finedick A-254 (Dainippon Ink and Chemicals Incorporated Glycidyl Group-Containing Solid Acrylic Epoxy) Equivalent 500) 84 parts, dodecanedioic acid (Ube Industries, aliphatic dibasic acid) 16 parts, benzoin 0.5 part, modaflow (Monsanto company leveling agent) 1 part and polyurethane polyurea particles (C-2) 40 Parts were mixed with a Henschel mixer, melt-kneaded at 100 ° C. for 100 revolutions with a Buser Conider PR46 type uniaxial kneader, cooled, finely pulverized, and classified with a 200-mesh wire net to form a powder coating (Z-1). Got The average particle size was 45 μm and the average circularity was 0.82.

Comparative Reference Example 2 (powder coating (Z-2) obtained by dry blending polyurethane polyurea particles for comparison and comparison)
Preparation) First, a powder coating material (T-1) was prepared in the same manner as in Example 1 except that polyurethane polyurea particles were not added. The average particle size was 26 μm and the average circularity was 0.91. Next, 100 parts of the clear powder coating material (T-1) was dry blended with 40 parts of polyurethane polyurea particles (C-1) to prepare a powder coating material (Z-2).

Powder coatings (X-1) obtained in Examples
(X-4) and comparative reference powder coatings (Z-1) to (Z-
2) is coated on a 0.8 mm thick polished steel plate treated with zinc phosphate with an electrostatic spray coating machine for powder coating, and then baked at 180 ° C. for 20 minutes to give a cured coating film. Various test plates formed were obtained. The evaluation judgment results of those coatings and the repaintability evaluation results of the paint,
Collectively shown in Table 1.

[0150]

[Table 1]

<< Guideline for Evaluation and Evaluation of Various Properties of Paint and Coating Film >> Film thickness: Measured with an electromagnetic film thickness meter.

Appearance: The specular gloss of 60 degrees was measured with a gloss meter, and the matte state of the coated surface was visually determined. ⊚: The gloss is 10 or less, the coated surface is uniform, and the surface is completely matt. ◯: Luster is 10 or less, and uneven gloss on the coated surface is recognized. X: The gloss is 10 or more and glossy.

Tactile sensation: When touched by hand, the degree of soft feeling was judged. ◎: Extremely soft feeling ○: Quite soft feeling × ； Hard and rigid feeling

Scratch resistance: # 000 steel wool was rubbed at a surface pressure of 30 g / cm ² , and 1 hour after that, the state of the coated surface was visually judged. ◎: There is no trace. ○: A slight mark is attached. ×: Scratches remain clearly.

Smoothness: Five-step evaluation and judgment were carried out by visual judgment. Evaluation "5"; Evaluation of very smooth and smooth coated surface "4"; Evaluation of small rounds "3"; Evaluation of large rounds "2"; Evaluation of large rounds and many fine dust skin When observed: Evaluation “1”; when there is a large round, the fine dust skin is remarkable, and the appearance of the coating film is significantly impaired.

Workability for re-coating: After recovering the powder coating which was not applied, it was re-coated and the difference in the matting degree from that of the first coating was visually judged. Evaluation ◎: No difference is recognized. Evaluation Δ: The matting degree is slightly inferior. Evaluation x: The matteness is poor and the appearance is completely different.

[0157]

EFFECTS OF THE INVENTION As will be apparent from the detailed description above, a coated article using the designable thermosetting powder coating material of the present invention is a resin particle having a three-dimensional crosslinked structure, a thermosetting resin and a cured resin Which is composed of an agent as an essential component, and in particular, an article coated with the composition of the present invention has an extremely high-grade feeling,
It can also be made with a high degree of matte coating formed. In addition, it is recognized that various effects aimed at by the present invention, that is, excellent repainting workability of the paint, are exhibited.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J038 CC022 CG001 CG002 DA062                       DA162 DB001 DD001 DD002                       DG002 DL032 GA03 GA06                       GA07 GA09 GA11 KA03 KA08                       LA06 MA02 NA01 PA02

Claims (5)

[Claims] 1. An organic solvent solution containing a thermosetting resin (A), a curing agent (B), and resin particles (C) having a three-dimensional crosslinked structure as essential components as a coating film forming component is spray-dried. The average particle size obtained by
Is a design thermosetting powder coating. 2. The designable thermosetting powder coating material according to claim 1, wherein the resin particles (C) having a three-dimensional cross-linking structure are pigmented resin particles. 3. An organic phase, wherein the resin particles (C) having a three-dimensional crosslinked structure described above contain a polyhydroxy compound and a polyisocyanate compound in which the isocyanate groups are stoichiometrically excessive, and the organic phase. A polyurethane polyurea particle obtained by an interfacial polymerization reaction between a stoichiometrically excessive isocyanate group in a phase and an equivalent amount of a polyamine compound or less, and a urethanization reaction inside the organic phase. The designable thermosetting powder coating material according to 1 or 2. 4. The thermosetting resin (A) has a curing-reactive group,
The designable thermosetting powder coating material according to claim 1, which is at least one selected from the group consisting of an epoxy group, a carboxyl group and a hydroxyl group. 5. The thermosetting resin (A) according to claim 1, wherein at least one curing reactive group is an epoxy group, and the curing agent (B) is an aliphatic dibasic acid. Design thermosetting powder coating.