Coating composition and method for forming multilayer coating film

Patent metadata

Field	Value
Publication number	US-11732154-B2
Application number	US-201816766882-A
Country	US
Kind code	B2
Filing date	Nov 30, 2018
Priority date	Dec 1, 2017
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

The present invention provides a coating composition capable of forming a coating film having a good appearance and design of a coating film and having coating film properties such as scratch resistance with a good balance. Furthermore, the present invention provides a method for forming a multilayer coating film including forming a coating film using the coating composition of the present invention.

First claim

The invention claimed is:

1. A coating composition consisting essentially of:
a hydroxyl group-containing acrylic resin (A);
a melamine resin (B1);
a half-ester group-containing copolymer (C) that is a copolymer of a polymerizable unsaturated monomer (a) having a half-esterified acid anhydride group and another copolymerizable monomer (b); and
a blocked isocyanate compound (D),
wherein
the polymerizable unsaturated monomer (a) has an acid anhydride group half-esterified with a monoalcohol having 1 to 8 carbon atoms, and
a total acid value of the half-ester group-containing copolymer (C) is 5.0 mgKOH/g or more and 240 mgKOH/g or less.

2. The coating composition according to claim 1 , wherein a number-average molecular weight of the half-ester group-containing copolymer (C) is 1000 or more and 10500 or less.

3. The coating composition according to claim 1 , wherein an acid value of the half-ester group-containing copolymer (C) is 10 mgKOH/g or more and 240 mgKOH/g or less.

4. The coating composition according to claim 1 , wherein a hydroxyl value of the hydroxyl group-containing acrylic resin (A) is 60 mgKOH/g or more and 200 mgKOH/g or less.

5. The coating composition according to claim 1 , wherein a content of the half-ester group-containing copolymer (C) is 3 parts by mass or more and 25 parts by mass or less per 100 parts by mass of a resin solid content of the coating composition.

6. The coating composition according to claim 1 , wherein a ratio of the melamine resin (B1) and the half-ester group-containing copolymer (C) contained in the coating composition is the melamine resin (B1)/the half-ester group-containing copolymer (C)=1/0.1 to 1/1 as expressed in solid content mass ratio.

7. The coating composition according to claim 1 , further comprising a particulate additive (E) including at least one species selected from the group consisting of an organic-inorganic hybrid polymer dispersion, an inorganic particle, and an organic resin-coated inorganic particle.

8. The coating composition according to claim 7 , wherein the average particle diameter of the particulate additive (E) is 10 nm or more and 1000 nm or less.

9. The coating composition according to claim 1 , wherein the coating composition is a clear coating composition.

10. A method for forming a multilayer coating film, comprising:
a step of applying a base coating composition to an object to be coated to form a base coating film or an uncured base coating film; and
a step of applying the coating composition according to claim 1 to the base coating film or to the uncured base coating film to form a coating film.

11. A method for forming a multilayer coating film, comprising:
a step of applying a primer surfacer composition to an object to be coated to form a primer surfacer film or an uncured primer surfacer film,
a step of applying a base coating composition to the resulting primer surfacer film or the uncured primer surfacer film to form a base coating film or an uncured base coating film, and
a step of applying the coating composition according to claim 1 to the base coating film or the uncured base coating film to form a coating film.

Assignees

• Nippon Paint Automotive Coatings Co Ltd

Inventors

• Miwa Yasunori
• Kakii Takuhiro
• Inazumi Takanori
• Mizuguchi Katsumi
• Iida Hiroshi
• Okada Takuma

Classifications

• C09D133/066 Primary

  containing -OH groups · CPC title

• B05D7/532

  the two layers being cured or baked together, i.e. wet on wet · CPC title

• B05D7/572

  all layers being cured or baked together · CPC title

• C08G18/544

  with nitrogen compounds · CPC title

• C08G18/73

  acyclic · CPC title