JP2002235038A - Powder coating material composition dispersed in nonaqueous medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating composition enabling the application of a powder coating material with a coating facility similar to the facility for conventional solvent-type coating materials without necessitating the use of a special coating facility for powder coating material. SOLUTION: The powder coating material composition dispersed in a nonaqueous medium contains solid resin particles of a powder coating material dispersed in a nonaqueous medium which is a non-solvent or a poor solvent for the solid resin particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous dispersion powder coating composition, and more particularly to a non-aqueous powder coating composition in which solid resin particles are used as a non-solvent or poor solvent for the solid resin particles. The present invention relates to a non-aqueous dispersion powder coating composition dispersed in an aqueous medium.

[0002]

2. Description of the Related Art Powder coatings are currently a problem because of their features such as the ability to increase the coating thickness in a single coating and the absence of any volatile solvent components. It is in the spotlight as a paint that can respond to environmental protection. However, the biggest problem when applying with a powder coating is that special equipment is required. That is, since the powder coating is applied to the object to be coated using air as a dispersion medium,
Equipment for transporting and applying powder paint requires equipment that is completely different from liquid paint, so existing solvent-type painting equipment cannot be used for painting with powder paint. Need to be remodeled.

[0003]

SUMMARY OF THE INVENTION The present invention provides a coating composition which can be coated without the above-mentioned problems, that is, it is not necessary to use a coating facility dedicated to powder coating, and the prior art It is an object of the present invention to provide a coating composition capable of coating a powder coating with a coating facility based on a solvent type coating.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have found that solid resin particles of a powder coating material are placed in a non-aqueous medium, preferably a non-aqueous medium having a small environmental load. The present inventors have found that, when dispersed as a liquid paint and supplied as a liquid paint, coating can be performed even with a coating facility based on a conventional solvent-based paint, and the present invention has been completed. That is, the non-aqueous dispersion powder coating composition of the present invention is that the powder coating solid resin particles are dispersed in a non-aqueous medium that is a non-solvent or poor solvent for the solid resin particles. Features.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The biggest problem in powder coating is the need for dedicated equipment as described above. However, this problem can be solved by dispersing the solid resin particles of the powder coating material in a non-aqueous medium, converting the solid resin particles to a liquid state, conveying the liquid resin to the tip of the coating machine, and applying the liquid coating composition.

That is, solid resin particles of a powder coating are dispersed in a non-aqueous medium which is a non-solvent or a poor solvent for the solid resin particles to form a non-aqueous dispersion powder coating composition, Paint. The liquid paint is applied to form a solid resin particle layer of a powder coating on the surface of the object to be coated, and the solid resin particle layer is heated and baked to form a film.

In order to prepare the non-aqueous dispersion powder coating composition of the present invention, first, solid resin particles of the powder coating are prepared.
The method for preparing the solid resin particles of this powder coating is a method for producing a normal powder coating.For example, the raw materials for powder coating are uniformly blended, kneaded and dispersed uniformly, rolled, cooled, and cooled. Crushing, and then dry grinding to form fine solid resin particles or suspension polymerization reaction to form fine solid resin particles in water, separating the solid resin particles from the water,
There is a method of collecting solid resin particles by drying, and solid resin particles obtained by any of these methods can be used.

[0008] Alkyd resin, acrylic resin, polyester resin, epoxy resin, melamine resin, block isocyanate resin, fluorine resin, silicone resin, amide resin, ABS resin, novolak resin, ketone resin , Butyral resin, phenoxy resin, polyolefin resin, etc., and these resins may be used alone or in combination of two or more at an arbitrary mixing ratio.

Specific examples of the above resin component and other components are as follows. <Acrylic resin> As acrylic monomers that can be used for the production of acrylic resin, methyl acrylate,
Ethyl acrylate, n-propyl acrylate, i-
Propyl acrylate, n-butyl acrylate, i-
Butyl acrylate, sec-butyl acrylate, t
-Butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, tridecyl acrylate,
Stearyl acrylate, cyclohexyl acrylate, benzyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-
Hydroxypropyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-
Butoxyethyl acrylate, 2-phenoxyethyl acrylate, ethyl carbitol acrylate, allyl acrylate, glycidyl acrylate, dimethylaminoethyl acrylate, acrylic acid, sodium acrylate, trimethylolpropane acrylate, 1,4-butanediol diacrylate, 1,6 And acrylic acid and acrylate monomers such as hexanediol acrylate, neopentyl glycol diacrylate, and pentaerythritol triacrylate.

Further, acrylic monomers that can be used in the production of acrylic resins include methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate,
2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, propyl methacrylate, benzyl methacrylate, isopropyl methacrylate, sec-butyl methacrylate,
Hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, allyl methacrylate, ethylene glycol methacrylate, triethylene glycol methacrylate,
Methacrylic acid and methacrylic acid such as tetraethylene glycol methacrylate, 1,3-butylene glycol methacrylate, trimethylolpropane methacrylate, 2-ethoxyethyl methacrylate, 2-methoxyethyl methacrylate, dimethylaminoethyl methyl chloride salt methacrylate, methacrylic acid, and sodium methacrylate Acid ester monomers can be mentioned.

In addition to the above-mentioned acrylic monomer components, copolymer components include vinyl monomers such as acrylamide, acrylonitrile, vinyl acetate, ethylene, propylene, isobutylene, butadiene, isoprene, chloroprene, glycidyl (meth) acrylate, methyl Epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth) acrylate, allyl glycidyl ether, 3,4-epoxycyclohexylmethyl (meth) acrylate, (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, etc. And a hydroxyl group-containing ethylenically unsaturated monomer such as a carboxyl group-containing ethylenically unsaturated monomer, hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate.

As a method for producing an acrylic resin, a method of producing a solid resin by synthesizing a high molecular weight resin by an ordinary solution polymerization method and then removing the solvent by a thin film heating and depressurizing method or a suspension polymerization method is used. There is a method of producing a solid resin by synthesizing a resin and removing water by a spray drying method or the like.

When the reactive polar group in the acrylic resin is a glycidyl group, a compound containing a polyfunctional carboxyl group such as sebacic acid or dodecanedicarboxylic acid, Acid anhydrides and the like can be used, and when the reactive polar group in the acrylic resin is a hydroxyl group or both a hydroxyl group and a carboxyl group, use a block isocyanate resin, a melamine resin, or the like. Can be.

Examples of the blocked isocyanate resin that can be used as a crosslinking agent include isocyanate resins obtained by adding and reacting an isocyanate monomer such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, and toluene diisocyanate with trimethylolpropane. Blocked isocyanate resins obtained by blocking a functionalized isocyanate resin, a hydrogenated polyfunctionalized isocyanate resin, or the like with caprolactone or an oxime.

When these blocked isocyanate resins are used as a cross-linking agent, it is preferable that the blocked isocyanate resin alone be a solid in view of the necessity of securing the stability of the solid resin particles. Blocked isocyanate resins blocked with ε-caprolactam and the like are preferred. However, even a liquid blocked isocyanate resin can be used by adjusting the amount of addition and the amount of pigment, or in combination with an acrylic resin or polyester resin having a high glass transition temperature.

<Polyester Resin> Examples of carboxylic acid components that can be used in the production of polyester resin include terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, succinic acid, glutaric acid, adipic acid, and the like.
Pimelic acid, suberic acid, azelaic acid, sebacic acid,
1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,2-octadecanedicarboxylic acid, isacosandicarboxylic acid,
Maleic acid, fumaric acid, cyclohexanedicarboxylic acid,
Hexahydrophthalic acid, tetrahydrophthalic acid, trimellitic acid, polyvalent carboxylic acids such as pyromellitic acid, lower alkyl esters and anhydrides of these polycarboxylic acids,
Alternatively, hydroxycarboxylic acids such as malic acid, tartaric acid, 1,2-hydroxystearic acid, and paraoxybenzoic acid can be exemplified.

The alcohol component which can be used in the production of the polyester resin includes, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3- Propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentaneddiol, 1,6-hexanediol, 1,9-nonanediol, 1,10- Decandiol, neopentyl glycol, spiroglycol
, 1,10-decanediol, 1,4-cyclohexanedimethanol, 2,2,4-trimethylpentane
Examples thereof include 1,3-diol, trimethylolethane, trimethylolpropane, glycerin, and pentaerythritol.

The polyester resin can be produced from the above-mentioned acid component and alcohol component as raw materials by a conventional method for producing a polyester resin for powder coating. For example, the above-mentioned various raw materials are used in an appropriate combination and in a proper mixing ratio, and esterification or transesterification is carried out at a temperature of 200 to 280 ° C. according to a conventional method. A polycondensation reaction is performed at 290 ° C. to obtain a resin having a high degree of polymerization, and then a depolymerization reaction is performed using an alcohol component to obtain a polyester resin.

For crosslinking and curing of these polyester resins,
It is preferable to use the above-mentioned block isocyanate resin, in which case the ratio of the latent isocyanate group of the block isocyanate resin contributing to the reaction to the hydroxyl group of the polyester resin is NCO / OH. 0.6- in ratio
It is preferably 1.2, and more preferably 0.8 to 1.0.

As a cross-linking agent that can be used together with the above-mentioned various resin components constituting the solid resin particles, generally, depending on the respective resin components, polybasic acids, acid anhydrides, amino compounds, glycidyl groups -Containing compound, aminoblast resin, dicyandiamide, block isocyanate
Resin, hydrazide and the like, and are appropriately selected and used according to the type of the resin.

The solid resin particles constituting the non-aqueous dispersion powder coating composition of the present invention may contain other than the above-mentioned resin component and cross-linking agent depending on the use of the non-aqueous dispersion powder coating composition of the present invention. In addition, coloring pigments for imparting design properties, adjusting the gloss value of the coating film, adjusting the hardness of the coating film, extender pigment for imparting the strength of the coating film, matting pigment for matting, for imparting magnetism For providing other functions such as magnetic pigments, conductive pigments for imparting conductivity, rust-preventive pigments, fluidity-imparting agents for imparting flowability, surface conditioners, curing accelerators, ultraviolet absorbers, etc. An additive or the like can be contained. Alternatively, these additives can coexist with the solid resin particles in the non-aqueous dispersion powder coating composition of the present invention. As a matter of course, depending on the design, solid resin particles that form a clear coating film containing no coloring pigment or extender may be used.

As coloring pigments, yellow iron oxide, titanium yellow,
Inorganic pigments such as red iron oxide, titanium oxide, zinc white, lithopone, lead white, zinc sulfide, antimony oxide, Hansa Yellow 5G, permanent yellow FGL, phthalocyanine blue, indanthrene blue RS, permanent red F5RK, brilliant first scarlet G And organic pigments such as Pariogen Red 3910. Examples of extenders include barium sulfate, barium carbonate, calcium carbonate, clay, silica powder, finely divided silica, diatomaceous earth, talc, basic magnesium carbonate, and alumina white.

The amount of these pigments to be present in the resin particles or to coexist with the resin particles in the non-aqueous dispersion powder coating composition is usually about 0.5 to 60% by PWC. It may not be added at all like paint. Conversely, when the amount of the pigment added is large, particularly in the case of a pigment having a high oil absorption, the smoothness of the formed coating film tends to be impaired. Here, PWC means Pigment Weight Concentration (pigment mass concentration), which is calculated by the following equation. PWC = [(% of pigment content) / (% of total paint solid content)] × 100

Further, the solid resin particles used in the non-aqueous dispersion powder coating composition of the present invention remain solid even when dispersed in a non-aqueous medium, have a storage stability of the coating, and are formed as a coating. Melt under baking and crosslinking conditions when forming a coating film,
Alternatively, it must be capable of softening to form a coating film. For this reason, the softening temperature of the solid resin particles is 35 to 200.
It is preferably in the range of ° C.

When the softening temperature of the solid resin particles is lower than 50 ° C., blocking may occur when the solid resin particles are stored for a long period of time, and when the softening temperature is higher than 150 ° C. The softening temperature of the solid resin particles is more preferably 50 to 150 ° C. since the smoothness and continuity of the coated film may be impaired during the formation of the coated film after application.

<Production of Solid Resin Particles> The above resin powder coatings such as acrylic resin powder coatings, polyester resin powder coatings, and epoxy resin powder coatings should be prepared according to the usual powder coating preparation methods. Can be. For example, resin,
Pigment, raw materials for powder coatings consisting of additives, etc. are uniformly blended, uniformly kneaded and dispersed by a melt kneading machine, rolled, cooled, coarsely crushed to prepare pellets, and then dry crushed. And fine solid resin particles can be formed.

In the step of mixing the above-mentioned various raw materials to obtain a compound, a color pigment, a cross-linking agent, an additive, and, if necessary, a small amount of a liquid raw material are mixed as homogeneously as possible with a solid resin raw material as a center. As a device for this, a flash mixer, a screw mixer, a conical blender, a V mixer, a tumbling mixer, a jet mixer, a kneader, a ribbon mixer, etc., which are ordinary devices for mixing raw materials, can be used.

Next, as a device used for melt kneading, there are a roll mill, a screw kneader, a mauler, a kneader and the like. As a device, in order to prevent crystallization of the resin and a cross-linking reaction inside the resin, a device capable of rapidly discharging the kneaded material from the device and cooling it after the melt kneading is preferable. In particular, when a cross-linking agent is contained in the powder coating solid resin particles, when the resin component and the cross-linking agent are homogeneously mixed in the melt-kneading step, since the resin component is heated to a softening temperature or higher, If the residence time during melt-kneading becomes longer, some of the resin components react with the cross-linking agent, and as a result, it becomes difficult to form a smooth and continuous coating film, or defects such as insufficient gloss occur. Tend to. Therefore, it is preferable to use an apparatus of a type in which supply is performed from one side and continuous discharge is performed from the other side.

If necessary, the discharged molten mixture is rolled, cooled, crushed, and crushed and classified into solid resin particles having a predetermined particle size distribution. The shape and size of the solid resin particles are preferably an average particle diameter of about one-half to one-third of the intended coating film thickness using the non-aqueous dispersion powder coating composition of the present invention. . However, from the viewpoint of storage stability of the non-aqueous dispersion powder coating composition, it is preferable that the solid resin particles have a finer particle diameter.

<Production method of non-aqueous dispersion powder coating composition> The non-aqueous medium in the non-aqueous dispersion powder coating composition of the present invention may be a non-solvent or a poor solvent for the solid resin particles. is necessary. When this non-aqueous medium dissolves a part of the solid resin particles, swells or softens, the solid resin particles tend to adhere to each other in the non-aqueous medium and lose fluidity as a paint, Even with a normal solvent, when the dissolving power for the solid resin particles to be used is small, the solvent can be used in consideration of the degree of the poor solvent.

Examples of usable non-solvents or poor solvents include methyl alcohol, ethyl alcohol, propyl alcohol, t-butanol, n-hexane, heptane, octane, petroleum benzine and white solvent. Gasoline and their isomers can be mentioned, and these may be used alone or in combination of two or more at an arbitrary mixing ratio.

The amount of the solid resin particles dispersed in the non-solvent or poor solvent is preferably 10 to 200 parts by mass, more preferably 30 to 150 parts by mass, per 100 parts by mass of the non-solvent or poor solvent. is there. When the amount is less than 10 parts by mass, that is, when the coating concentration is low, the amount of the non-solvent or the poor solvent required to achieve the desired coating film thickness becomes excessive per unit area, wasting resources and increasing costs. Becomes
On the other hand, when the amount exceeds 200 parts by mass, the fluidity of the non-aqueous dispersion powder coating composition is impaired, and coating becomes difficult.

The non-aqueous dispersion powder coating composition of the present invention is obtained by mixing the fine solid resin particles prepared as described above in a non-aqueous medium which is a non-solvent or a poor solvent with respect to the solid resin particles. Or may be prepared by wet pulverization in a non-aqueous medium which is a non-solvent or poor solvent instead of the above-mentioned dry pulverization.

Further, the dry pulverization and the wet pulverization can be combined to obtain a non-aqueous dispersion powder coating composition having a predetermined particle size distribution. Further, the solid resin particles of the emulsion resin and the solid resin particles formed by the suspension polymerization reaction are dried with an air dryer or the like to collect the solid resin particles, and the solid resin particles are dispersed in a non-solvent or a poor solvent to form a non-aqueous dispersion powder. It may be a body coating composition.

The non-aqueous dispersion powder coating composition of the present invention may contain additives such as a fluidity modifier or a suspending agent for the coating in a non-solvent or poor solvent, if necessary. With respect to the non-aqueous dispersion powder coating composition thus prepared, a bead mill or the like is used to further reduce the particle size distribution of the solid resin particles in the coating composition or to sharpen the particle size distribution. To adjust the particle size distribution.

<Preparation of Nonaqueous Dispersion Powder Coating Composition for Gloss Control> As a method for adjusting the gloss of a coating film, a matting pigment can be added to the nonaqueous dispersion powder coating of the present invention. Alternatively, the luster can be adjusted by using two or more types of solid resin particles in the coating composition and adjusting the difference in compatibility and reaction rate between the resin particles. As a gloss adjusting agent for the non-aqueous dispersion powder coating, colloidal silica, alumina, talc and the like which are usually used for coatings can be used. Fine particles of an acrylic resin or a fluororesin can also be added for the purpose of adjusting the gloss and reducing the frictional resistance, similarly to the matting pigment.

<Formation of Coating Film> The coating method using the non-aqueous dispersion powder coating composition of the present invention includes dip coating, brush coating, spin coater coating, air spray coating, electrostatic coating and the like. Is possible. The viscosity of the non-aqueous dispersion powder coating composition of the present invention is close to the viscosity of the used non-solvent or poor solvent, and remains extremely low until coating.
However, in the non-aqueous dispersion powder coating composition of the present invention,
The non-solvent or poor solvent in the coating composition does not have an affinity for the solid resin particles and, due to the capillary phenomenon of the solid resin particles, evaporates in a very short time after coating to coat the solid resin particle layer. Form on the surface of the object.

When the non-aqueous dispersion powder coating composition of the present invention does not contain a binder in the non-solvent or poor solvent, the non-solvent or poor solvent is evaporated and the solid resin particles with respect to the object to be coated are removed. The adhesive force is reduced, and the solid resin particle layer is easily peeled off by vibration or wind force. Therefore, the solid resin particles are heated to the softening temperature or higher as quickly as possible to fuse the solid resin particles to the object to be coated. However, at this time, if the temperature is rapidly increased to a value higher than the boiling point of the non-solvent or poor solvent, a pinhole may be generated in the coating film due to the balance between fusion and bumping. As a preventive measure, it is also effective to add a binder in a non-solvent or a poor solvent so that the solid resin particle layer adheres to the object to be coated with a binding force.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. In the examples, "parts" are parts by mass. Example 1 <Polyester resin non-aqueous dispersion powder coating composition> 32 parts of a polyester resin having a softening temperature of 120 ° C and an acid value of 45, 32 parts of a bisphenol A type epoxy resin having an epoxy equivalent of 910, 22 parts of titanium pigment, and 10 parts of talc , 5 parts of an acrylic oligomer (surface modifier) and 1 part of a benzotriazole-based crosslinking accelerator were blended in a screw mixer, and further uniformly mixed with a flash mixer.

As a melt kneading machine, a twin screw kneader was heated to 115 ° C., and a two-roll cooler was provided at the end of the melt kneading machine to enable rolling and cooling, and a hammer crusher was installed ahead of it. To prepare for kneading and crushing. The mixture mixed with the flash mixer is supplied from a feeder of a twin screw kneader, and is retained for about 20 seconds, melted, kneaded, and dispersed. It was dropped on a rolling roll of the present roll cooler, rolled, and cooled to near normal temperature in about 10 seconds. This plate-like resin was first pulverized with a hammer crusher to obtain a coarse powder having a size of about 0.5 mm.

The primary ground coarse powder was ground by a turbo mill and classified by a 120 mesh classifier to obtain solid resin particles. 55 parts of the solid resin particles were dispersed in 45 parts of petroleum benzine (boiling point: 78 ° C. to 82 ° C.) to obtain a polyester resin non-aqueous dispersion powder coating composition.

While stirring this polyester resin non-aqueous dispersion powder coating composition, an aluminum member subjected to a chromate treatment was immersed in the composition, and the resultant was pulled up. After waiting for the drop of the polyester resin non-aqueous dispersion powder coating composition to drop from the aluminum member, it was taken out of the dipping tank and air-dried for 7 minutes. During this time, the gloss of the applied coating surface disappeared. The coated aluminum member was kept in a drying oven maintained at 200 ° C. for 10 minutes, and then taken out and cooled.

The thickness of the coating film on the aluminum member is 30 μm at the thinnest part at the top when pulled up from the dipping tank,
The thickness was uniform at 80 μm in the thick portion immediately below the lower part of the dripping, and 50 μm in the middle. The coating appearance is glossy 8.
8. The pencil hardness was H, and a uniform, smooth and good coating film was completed. When this non-aqueous dispersion powder coating composition was allowed to stand, solid resin particles in the coating precipitated, but could be easily redispersed by shaking the entire container during coating.

Example 2 <Polyester resin non-aqueous dispersion powder coating composition> Polyester resin (Finedick M8023, manufactured by Dainippon Ink and Chemicals) having a softening temperature of 110 ° C and a hydroxyl value of 40 56
Part, block isocyanate resin having an NCO content of 15% (IPDI-B1530, manufactured by Daicel Huls) 11
Parts, 1 part of dibutyltin dilaurate (surface conditioner), 2 parts of benzoin (flowability-imparting agent), 29 parts of titanium oxide and 1 part of carbon black in the same manner as in Example 1, melt-kneaded, Extrude, crush, classify and average particle size 25μ
m of solid resin particles.

One part of the polyamide thickener was mixed with n-hexane 4
Dispersed in 9 parts to give a milky white solution. While stirring, 50 parts of solid resin particles were added to this solution and dispersed to obtain a polyester resin non-aqueous dispersion powder coating composition. The polyester resin non-aqueous dispersion powder coating composition was air-spray coated on a mild steel sheet member treated with zinc phosphate.

Shortly after the coating, the gloss of the coating film surface disappeared. Further, even when an impact was applied to the coating film, the solid resin particles did not fall. The coated member was kept in a drying oven maintained at 180 ° C. for 20 minutes, then taken out and cooled.
The coating film thickness of the object to be coated was uniform at 50 μm. Also,
The coating film had a gloss of 90 and a pencil hardness of HB, and was a uniform, smooth and good coating film.

Example 3 <Acrylic resin non-aqueous dispersion powder coating composition> In a reaction vessel, 60 parts of methyl methacrylate, 6 parts of butyl acrylate, 33 parts of glycidyl methacrylate and 1 part of azoisobutyronitrile were stirred and mixed. At 120 ° C. While maintaining the contents of the reaction tank at 120 ° C. and stirring, 100 parts of xylol was dropped from the dropping tank in one hour,
Thereafter, the temperature was maintained for 2 hours. Thereafter, 0.3 parts of azoisobutyronitrile was further added, and the mixture was kept at 150 ° C. for about 4 hours and polymerized to obtain a resin solution. The resin solution was treated with a thin film vacuum dryer to remove the solvent, and a solid acrylic resin was obtained. This acrylic resin had a softening temperature of about 55 ° C., an epoxy equivalent of 430, and a molecular weight of about 7,000.

77 parts of this acrylic resin, 19 parts of dodecanedicarboxylic acid, 1 part of an acrylic oligomer (surface modifier) and 3 parts of benzoin (flowability-imparting agent) were blended in the same manner as in Example 1 and melt-kneaded. Extruded, pulverized and classified to obtain acrylic solid resin particles having an average particle diameter of 10 μm.

One part of the polyamide thickener was mixed with n-hexane 3
Dispersed in 9 parts to give a milky white solution. While stirring, 50 parts of acrylic solid resin particles were added to this solution and dispersed to obtain an acrylic resin non-aqueous dispersion powder coating composition. This acrylic resin non-aqueous dispersion powder coating composition was air-spray coated on a mild steel sheet member treated with zinc phosphate.

The coated member was kept in a drying oven maintained at 150 ° C. for 20 minutes, then taken out and cooled. The coating thickness of the object to be coated was 35 μm, and the appearance of the coating film was smooth and excellent.

[0051]

The non-aqueous dispersion powder coating composition of the present invention is obtained by dispersing powder coating solid resin particles in a non-aqueous medium which is a non-solvent or a poor solvent for the solid resin particles. Therefore, there is no need to use a special coating equipment for powder coating, and the coating can be performed with a coating equipment based on the conventional solvent type coating.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiji Inaba 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Haruhiko Okazaki 878 Mitsubuchi Nishinomon, Mitsubuchi, Komaki City, Aichi Prefecture Japan Paint Co., Ltd. Komaki Plant (72) Inventor Akiko Tagami 878 Nishinomon, Mitsubuchi, Komaki City, Aichi Prefecture Dai Nippon Paint Co., Ltd. Komaki Plant F term (reference) 4J038 CB001 CD091 CE071 CG001 CP081 DA061 DA161 DB001 DD001 DF061 DG261 DH001 DL001 KA08 MA07 MA10 MA14 NA23 PA02

Claims (6)

[Claims] 1. A non-aqueous dispersion powder coating composition comprising solid resin particles dispersed in a non-aqueous medium which is a non-solvent or a poor solvent for the solid resin particles. object. 2. The method according to claim 1, wherein the solid resin particles are alkyd resin, acrylic resin, polyester resin, epoxy resin, melamine resin,
Contains at least one member selected from the group consisting of block isocyanate resin, fluorine resin, silicone resin, amide resin, ABS resin, novolak resin, ketone resin, butyral resin, phenoxy resin and polyolefin resin. The non-aqueous dispersion powder coating composition according to claim 1, characterized in that: 3. The non-aqueous dispersion powder coating composition according to claim 1, wherein the solid resin particles contain a pigment in a PWC of 0.5 to 60%. 4. The softening temperature of the solid resin particles is 35.degree.
The temperature is within the range of ° C.
The non-aqueous dispersion powder coating composition as described in the above. 5. The non-aqueous medium which is a non-solvent or a poor solvent is methyl alcohol, ethyl alcohol, propyl alcohol,
t-butanol, n-hexane, heptane, octane,
The non-aqueous dispersion powder according to claim 1, 2, 3 or 4, wherein the powder is a single substance selected from the group consisting of petroleum benzine, white gasoline and isomers thereof, or a combination of two or more. Paint composition. 6. The method according to claim 1, wherein the mass ratio of the non-aqueous medium, which is a non-solvent or a poor solvent, to the solid resin particles is in the range of 100 to 10 to 200. Non-aqueous dispersion powder coating composition.