Method of forming a multi-layer paint film

Patent metadata

Field	Value
Publication number	US-9718097-B2
Application number	US-201314410675-A
Country	US
Kind code	B2
Filing date	May 23, 2013
Priority date	Jun 28, 2012
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A method of forming multi-layer paint films comprises forming a first base paint film, wherein an aqueous first base paint (A) is coated over an object; forming a second base paint film wherein a second aqueous base paint (B) is coated over the uncured first base paint film; forming a clear paint film wherein a clear paint (C) is coated over the uncured second based paint film; and heating and curing the first base paint film, the second base paint film, and the clear paint film at the same time and in which the aqueous first base paint (A) includes as the base resin a water-soluble or water-dispersible acrylic resin (A1) and one or more type of water-soluble or water-dispersible resin (A2), selected from among the polyester resins, polyurethane resins and acrylic-urethane resins, both (A1) and (A2) having a weight average molecular weight of from 10,000 to 100,000.

First claim

The invention claimed is:

1. A method of forming a multi-layer paint film comprising:
forming a first base paint film wherein an aqueous first base paint (A) is coated over an object which is to be painted;
wherein the aqueous first base paint (A) includes a melamine resin and, as a base resin,
a) a water-soluble or water-dispersible acrylic resin (A1) having a weight average molecular weight in the range of from 10,000 to less than 50,000, and
b) a water-soluble or water-dispersible resin (A2), selected from the group consisting of polyester resins, polyurethane resins, and acrylic-urethane resins, the water-soluble or water-dispersible resin (A2) having a weight average molecular weight in the range of from 10,000 to 100,000;

forming a second base paint film wherein an aqueous second base paint (B) comprising a melamine resin, an acrylic resin according to (A1) and a polyurethane resin according to (A2) is coated over the first base paint film without curing;
forming a clear paint film wherein a clear paint (C) is coated over the second base paint film without curing; and
heating and curing the first base paint film, the second base paint film, and the clear paint film at the same time.

2. The method of forming a multi-layer paint film of claim 1 , wherein the solid fraction mass ratio represented by the (A1) component/the (A2) component is from 0.3 to 0.6.

3. The method of forming a multi-layer paint film of claim 1 , wherein the glass transition temperature of the (A1) component is from 30 to 80° C.

4. The method of forming a multi-layer paint film of claim 1 , wherein the glass transition temperature of the (A2) component is from −50 to 0° C.

5. The method of forming a multi-layer paint film of claim 1 , wherein the solid fraction mass ratio represented by the (A1) component+the (A2) component/the whole of the solid fraction of the base resin of the first aqueous base paint (A) is at least 0.8.

6. The method of forming a multi-layer paint film of claim 1 , wherein the second aqueous base paint (B) includes as base resin a water-soluble or water-dispersible resin having a weight average molecular weight in the range of from 10,000 to 100,000.

Assignees

• Basf Coatings Gmbh

Inventors

• Nakashima Hisayuki
• Mori Souichi
• Miyamoto Takamasa

Classifications

• C08F220/1804

  C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate · CPC title

• C08G18/4233

  derived from polymerised higher fatty acids or alcohols · CPC title

• C08G18/755

  and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate · CPC title

• C09D167/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds (C09D167/06 takes precedence) · CPC title

• C08F220/18

  with acrylic or methacrylic acids · CPC title