Actinic-ray-curable coating composition

Patent metadata

Field	Value
Publication number	US-10519318-B2
Application number	US-201615770351-A
Country	US
Kind code	B2
Filing date	Oct 24, 2016
Priority date	Oct 27, 2015
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

This invention provides the following active energy ray-curable coating composition: an active energy ray-curable coating composition comprising (A) a polymerizable unsaturated group(s)-containing acrylic resin having a weight average molecular weight in the range of 5,000 to 30,000, (B) a urethane (meth)acrylate having a weight average molecular weight in the range of 1,000 or more but less than 5,000 and containing an average of two to four polymerizable unsaturated groups per molecule, (C) a polymerizable unsaturated compound having a weight average molecular weight in the range of 200 or more but less than 1,000 and containing an average of two to nine polymerizable unsaturated groups per molecule, and (D) a photopolymerization initiator, the molecular weight between crosslinks of a cured coating film obtained by applying the active energy ray-curable coating composition being in the range of 300 to 900 g/mol.

First claim

The invention claimed is:

1. A method for forming a coating film, comprising:
applying an active energy ray-curable coating composition as an uppermost layer to a substrate to form an uncured coating film; and
irradiating the uncured coating film with active energy rays to cure the coating film,
wherein the active energy ray-curable coating composition comprises:
(A) a polymerizable unsaturated group(s)-containing acrylic resin having a weight average molecular weight in the range of 5,000 to 30,000:
(B) a urethane (meth)acrylate having a weight average molecular weight in the range of 1.000 or more but less than 5,000 and containing an average of two to four polymerizable unsaturated groups per molecule;
(C) a polymerizable unsaturated compound having a weight average molecular weight in the range of 200 or more but less than 1,000 and containing an average of two to nine polymerizable unsaturated groups per molecule; and
(D) a photopolymerization initiator,

wherein the molecular weight between crosslinks of a cured coating film obtained by applying the active energy ray-curable coating composition is in the range of 300 to 900 g/mol, and
wherein a gloss of a surface coated with the coating film measured based on the specular gloss (60 degrees) according to JIS K5600-4-7 (1999) is 70 or more, on the condition that the surface coated with the coating film is prepared by applying the active energy ray-curable coating composition to an acrylonitrile-butadiene-styrene substrate, acrylonitrile-ethylene-styrene substrate or acrylonitrile-styrene-acrylate substrate to a film thickness of 30 μm using an air spray, setting the substrate at room temperature for 2 minutes and then preheating at 80° C. for 3 minutes, and performing UV irradiation using a metal halide lamp.

2. A method for forming a coating film, comprising:
applying an active energy ray-curable coating composition as an uppermost layer to a substrate to form an uncured coating film; and
irradiating the uncured coating film with active energy rays to cure the coating film,
wherein the active energy ray-curable coating composition comprises:
(A) a polymerizable unsaturated group(s)-containing acrylic resin having a weight average molecular weight in the range of 5,000 to 30,000;
(B) a urethane (meth)acrylate having a weight average molecular weight in the range of 1,000 or more but less than 5,000 and containing an average of two to four polymerizable unsaturated groups per molecule;
(C) a polymerizable unsaturated compound having a weight average molecular weight in the range of 200 or more but less than 1,000 and containing an average of two to nine polymerizable unsaturated groups per molecule; and
(D) a photopolymerization initiator,

wherein the molecular weight between crosslinks of a cured coating film obtained by applying the active energy ray-curable coating composition is in the range of 300 to 900 g/mol, and
wherein a gloss retention (%) of the coating film after being washed 15 times in a car wash at 20° C. is 70% or more, on the condition that the coating film is prepared by applying the active energy ray-curable coating composition to an acrylonitrile-butadiene-styrene substrate, acrylonitrile-ethylene-styrene substrate or acrylonitrile-styrene-acrylate substrate to a film thickness of 30 μm using an air spray, setting the substrate at room temperature for 2 minutes and then preheating at 80° C. for 3 minutes, and performing UV irradiation using a metal halide lamp, and that the coating film is attached to an automobile roof.

3. The method according to claim 1 , wherein, in the active energy ray-curable coating composition, an amount of the component (A) on a solids basis is in a range of 20 to 70 mass %, an amount of the component (B) on a solids basis is in a range of 10 to 60 mass %, and an amount of the component (C) on a solids basis is in a range of 1 to 30 mass %, based on a total solids content of the components (A), (B), and (C).

4. The method according to claim 2 , wherein, in the active energy ray-curable coating composition, an amount of the component (A) on a solids basis is in a range of 20 to 70 mass %, an amount of the component (B) on a solids basis is in a range of 10 to 60 mass %, and an amount of the component (C) on a solids basis is in a range of 1 to 30 mass %, based on a total solids content of the components (A), (B), and (C).

5. The method according to claim 1 , wherein the active energy ray-curable coating composition further comprises an ultraviolet absorber and/or a light stabilizer.

6. The method according to claim 2 , wherein the active energy ray-curable coating composition further comprises an ultraviolet absorber and/or a light stabilizer.

7. The method according to claim 1 , wherein the cured coating film has a glass transition temperature in a range of 20 to 80° C.

8. The method according to claim 2 , wherein the cured coating film has a glass transition temperature in a range of 20 to 80° C.

Assignees

• Kansai Paint Co Ltd

Inventors

• Gotou Kouta
• Okiyama Haruhiko
• Nakaoka Haruka

Classifications

• C08F2/54

  by X-rays or electrons · CPC title

• C08F220/343

  in the form of urethane links · CPC title

• C08F2810/50

  wherein the polymer is a copolymer and the modification is taking place only on one or more of the monomers present in minority · CPC title

• C09D175/16

  having terminal carbon-to-carbon unsaturated bonds · CPC title

• C08F8/14

  Esterification · CPC title