Nippon Ester Co., Ltd.

Katsuyoshi Atsumi

Tokuzo Nozaki

Katsuya Fujimoto

Makiko Sakai

Akio Nakagi

Yoshiho Toyota

Singo Sasaki

a resin composition for a powder coating comprising a polyester A, which does not substantially set to gel and has a hydroxyl value of at least 1,200 g eq/10.sup.6 g, a polyester B, which does not substantially set to gel and has a hydroxyl value of from 200 to 1,000 g eq/10.sup.6 g, and an inner blocked isocyanate hardener, wherein the weight ratio of polyester A to polyester B is from 70:30 to 10:90 and the difference (absolute value) in gel time between these polyesters A and B is at least 3 minutes.

Resin composition for powder coating

A resin composition for powder coating which comprises a substantially un-gelled polyester A having a hydroxyl value of from 1,200 to 5,000 g eq/10.sup.6 g, a substantially un-gelled polyester B having a hydroxyl value of from 200 to 1,000 g eq/10.sup.6 g, tetramethoxymethyl glycoluril as a curing agent and an organic sulfonic acid compound as a curing catalyst, wherein the weight ratio of polyester A to polyester B is from 70:30 to 10:90 and the difference (absolute value) in the gel time between polyester A and polyester B is at least 3 minutes.

Resin composition for powder coatings

A resin composition for powder coating which comprises a substantially un-gelled polyester A having an acid value of from 1,200 to 5,000 g eq/10.sup.6 g, a substantially un-gelled polyester B having an acid value of from 200 to 1,000 g eq/10.sup.6 g and triglycidyl isocyanurate as a curing agent, wherein the weight ratio of polyester A to polyester B is from 70:30 to 10:90 and the difference (absolute value) in the gel time between polyester A and polyester B is at least 3 minutes. A resin composition for powder coating which causes no problems of polluting a baking oven, which shows less weight loss at the time of reaction and which can form a semi-mat or completely mat stable paint film is provided. These advantages cannot be obtained from any prior art powder coating that comprises a polyester having a large quantity of terminal hydroxyl groups and a blocked isocyanate-based curing agent.

A resin composition for a matte powder coating comprising a polyester A having a hydroxyl value of at least 1,200 g eq/10.sup.6 g, a polyester B having a hydroxyl value of from 200 to 1,000 g eq/10.sup.6 g and a blocked isocyanate hardener, wherein the weight ratio of polyester A to polyester B is from 70:30 to 10:90, the difference (absolute value) in gel time between polyester A and polyester B is at least 3 minutes and the difference (absolute value) in acid value between these polyesters is at least 20 g eq/10.sup.6 g is disclosed.

Resin composition for matte powder coating

A heat-curable resin composition obtained by mixing (A) a polyester resulting from the depolymerization of a polyester of a high degree of polymerization comprising an aromatic dicarboxylic acid and an aliphatic dialcohol using a compound containing about 2 to about 12 carboxyl groups per molecule with (B) a polyoxirane compound containing about 2 to about 100 oxirane groups per molecule. A heat-curable resin composition obtained by adding to the above resin composition a salt formed between an aliphatic monocarboxylic acid containing 2 to 20 carbon atoms and an element of Group II of the Periodic Table as a curing accelerator is an especially superior material for powder paints. Powder paints prepared from these heat-curable resin compositions provide coatings having superior appearance and properties upon baking after coating by a method such as an electrostatic spray coating method or a fluidized dip coating method.

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Aichi, Japan

Katsuyoshi Atsumi