Nippon Paint Compnay, Ltd.

Akimitsu Uenaka

Koichi Tsutsui

Yuji Toyoda

Tasaburo Ueno

Ryuzo Mizuguchi

Shinichi Ishikura

Atsushi Takahashi

Shin-ichi Ishikura

Kouichi Tsutsui

Yasushi Shiomi

Atushi Takahashi

Hideki Ichimura

Satoshi Yamamoto

Masahiro Yamamoto

Masayuki Maruta

Teruaki Kuwajima

Katsuaki Kida

Takaharu Izumo

Haruhiko Sawada

Toshiharu Nakaya

Zenichi Yasuda

Takanobu Ueda

John Kenny

Harunori Gohji

Teruyoshi Fujishima

Kenji Shindow

Tasaburo Uneo

An electrostatic powder coating method of forming an undercoating film having a volume specific resistivity of not more than 10.sup.13 .OMEGA..multidot.cm and a thickness of not more than 200 .mu.m on a metal surface and forming an overcoating layer on the undercoating film by electrostatic powder coating. The undercoating film is composed of a plurality of layers with only the top layer containing a conductive material.

Electrostatic powder coating method

A powder coating composition contains acrylic resin (A) containing at least 40 percent by weight of a glycidyl-group-containing monomer and having a solubility parameter which is in the range of 11.0 to 11.6 and a glass transition temperature of at least 20.degree. C., a surface modifier (B) consisting of a polymer having a solubility parameter which is in the range of 10.4 to 11.0, and polyvalent carboxylic acid (B). The surface modifier (B) is in a content of 0.1 to 4 parts by weight with respect to a total content of 100 parts by weight of the acrylic resin (A) and the polyvalent carboxylic acid (C), while the components are so mixed with each other that the amount of carboxylic groups contained in the polyvalent carboxylic acid (C) is at an equivalence ratio of at least 0.5 to the amount of glycidyl groups contained in the acrylic resin (A).

Powder coating composition

The present invention relates to a two coat one bake coating method in which the aqueous base coating composition and the powder clear coating composition are applied onto substrates in automobile painting processes. In accordance with the present invention, the aqueous base coat contains: (a) a vinyl polymer prepared by copolymerizing 8 to 30% by weight of an amido group containing ethylenic monomer, an acidic group containing ethylenic monomer, a hydroxyl group containing ethylenic monomer and at least one other ethylenic monomer; (b) an aqueous dispersion of hydrophilic group containing oligomers; and (c) pigment. The clear powder coating composition comprises an epoxy group containing acrylic resin, and may carry polymer microparticles on each powder particle.

Two coat one bake coating method

A powder coating comprising a thermosetting resinous composition comprising a base resin having 2 or more oxirane groups in its molecule and a hardener for epoxy resin, which is characterized by further containing 0.5 to 10% by weight based on the base resin weight of a vinyl resin containing 1 to 10% by weight of at least one aliphatic dicarboxylic acid selected from thiomalic acid, maleic acid, fumaric acid and itaconic acid and having a number average molecular weight of 1000 to 8000 and a glass transition temperature of -40.degree. to 100.degree. C. The coating obtained is excellent in smoothness, gloss and image clarity.

The object of the present invention is to provide a powder coating excellent in storage stability and in coat surface smoothness. The present invention relates to a powder coating comprising a binder resin and a curing agent, characterized in that said curing agent has particle size characteristics such that the average particle size is 0.3 to 7 .mu.m and particles having a particle size not smaller than 20 .mu.m account for not less than 10% by weight of all curing agent particles.

Powder coating

There is obtained with greater efficiency a powder coating having an average particle diameter smaller and a particle size distribution range narrower than those currently made by conventional methods. The method to obtain the powder coating comprising; introducing a solid mixture of coating materials between a rotor and a stator; the rotor being supported in such a manner as to be rotating round the shaft center and, on its periphery, being arranged with multiple convex lines extending in a direction of the shaft and being lined up along the periphery; the stator having a cylindric rotor-opposite face arranged with a certain interspace between this face and the rotor periphery and having, on the rotor-opposite face, multiple convex lines extending in the direction of the shaft and being lined up along the circumference, wherein the rotor-opposite face is arranged in such a manner as to be capable of opening in order to expose the rotor periphery; and then pulverizing finer said mixture by said rotating rotor and said stator.

Method for making a powder coating

A resinous composition for powder coating, comprising (A) an acrylic resin and (B) a hardener, the acrylic resin being composed of (a) t-butyl methacrylate and/or t-butyl acrylate, (b) an ethylenically unsaturated monomer having a reactive functional group and (c) other ethylenically unsaturated monomer(s) than the said (a) and (b) which is (are) non-reactive with the functional group of (b), the reactive functional group content being 0.0010-0.0046 mol/g of resin, the glass transition temperature being 30-110.degree. C. and the number average molecular weight being 1,000-20,000, and the hardener having in its molecule 2 or more functional groups which are reactive with the reactive functional group possessed by the acrylic resin. The powder coating based on the present resinous composition is useful for the coating of construction material, auto-mobile and the like and is excellent in low temperature curing properties, storage stability and can result an excellent film even when used a stored powder.

Resinous composition for powder coating

A powder coating comprising, as main components. (A) a carboxyl group containing resin having a number average molecular weight of 1000-30000, an acid value of 5-200 KOH mg/g and a glass transition temp. of 20.degree.-120.degree. C., and (B) a polyglycidyl compound obtained by addition of a polyester oligomer having 2 or more carboxyl groups and a number average molecular weight of 200-1200, with an epoxy compound of the formula: ##STR1## , the ratio of carboxyl groups in (A) to glycidyl groups in (B) being, in terms of equivalent ratio, 0.5 to 2.0. This powder coating may result a coating with excellent processability, impact strength and the like and is excellent in storage stability, hardening properties either at high or low temperature and even when used a stored powder may result a coating with excellent processability.

A powder coating which is specifically useful for the containing of electric appliance, office appliance and the like and is excellent, inter alia, stain resistance of the formed coating is provided, the powder coating comprising (a) a base resin having a reactive functional group, (b) a hardener having in its molecule 2 or more functional groups which are reactive with the functional group of the base resin and (c) an acrylic resin containing 40 100 % by weight of the total of the constituting monomers of t-butyl acrylate and/or t-butyl methacrylate.

A powder coating which is excellent in stain resistance

The invention concerns a coating powder composition comprising (A) a carboxyl group containing polyester resin having a number average molecular weight of 1,000.about.20,000, an acid value of 10.about.100, a glass transition temperature of 35.degree.-120.degree. C. and an SP value of 9.8.about.11.5, and (B) glycidyl trimellitate, wherein the equivalent weight ratio of carboxyl the groups of said (A) to the glycidyl groups of said (B) is 1:2 to 2:1. The coating powder composition is specifically suitable for a high-temperature-short time baking and capable of resulting in a coating having excellent film properties including bending and processability and which coating is highly-crosslinked.

Coating powder composition

Coating composition

The invention concerns powder coatings comprising thermoplastic or thermosetting type resin powder particles, each particle carrying at least on the surface thereof, a number of microparticles having an average diameter of 0.001 to 10.mu. of such resin as having a glass transition temperature of 50.degree. to 150.degree. C. and a SP value of 9 to 15, said microparticle optionally containing UV absorber or antioxidant or hardening catalyst, the weight ratio of said microparticles to the total weight of the powder coatings being 0.05 to 30% by weight. The present powder coatings are excellent in blocking resistance and capable of forming a coating with excellent stain resistance, coating appearance and other desired properties.

Powder coatings

Aqueous coating composition comprising water insoluble resinous powder, aqueous resin, pigment and other optional additives including hardener, characterized by the fact that said water insoluble resinous powder is composed of a polymer obtained by reacting a mixture of epoxy resin and a resin having epoxy reactive functional groups, or a resin having both epoxy groups and epoxy reactive functional groups, with an amine in an amount sufficient to cause ring-opening of 10 to 50% of the total epoxy groups, or composed of carboxyl bearing resin admixed and reacted with high boiling basic compound. These compositions are excellent in storage stability, application characteristics and film performance.

Aqueous coating composition and preparation thereof

A coating composition which comprises (A) a vinylic monomer-copolymerized resin having a hydroxyl group and a carboxyl group and (B) an alkoxylated amine-formaldehyde condensate as a curing agent for the resin (A). When the coating composition is used as a base coating composition and/or as a clear coating composition in the two coat-one bake coating system, the resulting coating film shows excellent weather resistance with good appearance.

Growing community of inventors

Suita, Japan

Akimitsu Uenaka