Asahi Kasei Kogyo Kabushiki Kaisha

Yoshio Matsumoto

Shunji Matsuo

Mikio Sato

Kazuo Toyomoto

Jyoji Ibata

Katsuyuki Nakamura

Kiichiro Sasaguri

Sumitaka Nogami

Kazuhiro Suzuoki

Keiichi Waki

Tooru Okada

Yashio Hayashi

Bunzo Uda

A novel polyester type powder coating composition which includes a specific self-hardening polyester of air-hardening type comprising as main ester-constituting monomer units, (1) at least one polycarboxylic acid component containing at least 10 mole %, based on the polycarboxylic acid component, of at least one aromatic polycarboxylic acid component (A) and (2) at least one polyhydric alcohol component, having in its main chain at least one terminal blocked with a monofunctional unsaturated alicyclic compound component (B) and having a softening point of 30.degree. to 150.degree. C. This composition is excellent in storage stability and adaptability to either thin coating or thick coating, and when it is applied onto an article to be coated and baked at a temperature of 170.degree. to 230.degree. C. for 5 to 30 minutes, a coating excellent in appearance, mechanical strength, gloss and reflection sharpness can be formed advantageously without generating undesired gases at the baking.

Polyester type powder coating composition

A thermosetting powder coating composition having good handling characteristics and capable of being baked under relatively mild conditions and providing a coating having practically satisfactory properties. This coating composition is prepared by incorporating in 100 parts by weight of an epoxy group-containing acrylic or methacrylic copolymer having a glass transition point of 30.degree. to 90.degree. C. and a weight average molecular weight of 2,500 to 30,000, said copolymer consisting of 3 to 35% by weight of acrylate or methacrylate monomer units and 97 to 65% by weight of ethylenically unsaturated monomer units, 3 to 40 parts by weight of a specific diphenol having at its both terminals hydroxybenzoic acid ester structures as represented by the general formula: ##STR1## wherein R.sub.3 stands for a hydrocarbon radical having 2 to 20 carbon atoms or a linking group containing, at least at its both terminals, hydrocarbon radicals and in its main chain at least one member selected from the group consisting of an ether linkage, ester linkage, urethane linkage and amide linkage, and having totally 4 to 20 carbon atoms. Especially good results are obtained when a specific phenol compound containing in the molecule one phenolic hydroxyl group and either one carboxyl group or one hydroxyl group, or a specific benzoic acid compound containing in the molecule two carboxylic acid groups are further incorporated in this powder coating composition.

Powder coating composition

An acrylic powder resin coating composition having good handling characteristics and capable of providing a coating having a well-balanced combination of the reflection sharpness and other physical properties is provided. This coating composition is prepared by incorporating in an acrylic copolymer resin a compound containing in the molecule one phenolic hydroxyl group and one carboxyl group and further containing at least one ester linkage between the benzene nucleus to which the phenolic hydroxyl group is bonded and the carboxyl group, said compound having a melting point of 45.degree. to 160.degree.C. and a number average molecular weight of up to 10,000. Especially good results are obtained when a polyester resin having a melting point of 40.degree. to 160.degree.C. and a number average molecular weight of 1,000 to 10,000 is further incorporated in this powder coating composition.

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Fuji, Japan

Yoshio Matsumoto