Coating composition for undercoat and coating method for repair employing the same

• US 20020061957A1
• Filed: 09/27/2001
• Published: 05/23/2002
• Est. Priority Date: 09/28/2000
• Status: Abandoned Application

• Current Assignee: Kansai Paint Company Limited
• Original Assignee: Kansai Paint Company Limited
• Inventors: Akane, Nobuhito, Hara, Sadamu, Yanagiguchi, Takeo, Tomita, Shinji
• Application Number:
  US09/963,526
• Publication Number:
  US 20020061957A1
• Time in Patent Office: Days
• US Class Current: 524/507
• CPC Class Codes: C08G 18/6254 Polymers of alpha-beta ethylenically unsaturated carboxylic acids and of esters of these acids containing hydroxy groups
• CPC Class Codes: C08L 33/00 Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
• CPC Class Codes: C09D 175/04 Polyurethanes

Abstract

A coating composition for undercoat of the present invention comprises (A) an acrylic resin having a hydroxyl value of 30 to 85 and a weight average molecular weight of 1000 to 30000, (B) a pigment, (C) resin fine particles, (D) a polyisocyanate compound, and (E) a curing catalyst. The employment of an isocyanate-rich two-pack type coating effects a high content of solid matter at spray coating which allows the formation of a thick film, and enables the formation of a coated film curable within a short period of time after coating and excellent in substrate-shielding ability and solvent resistance.

Claims

1. A coating composition for undercoat comprising:

(A) an acrylic resin having a hydroxyl value of 30 to 85 and a weight average molecular weight of 1000 to 30000,

(B) a pigment,

(C) resin fine particles,

(D) a polyisocyanate compound, and

(E) a curing catalyst;

wherein;

a ratio of isocyanate group in the (D) component to 1 equivalent of hydroxyl group in the (A) component is 2.0 to 4.0 equivalents;

content of the (B) component is from 100 to 500 parts by weight relative to 100 parts by weight of resin solid matter; and

the (C) component is mixed so as to be from 0.1 to 5% by weight as a solid matter relative to the weight of the (B) component.

2. The coating composition for undercoat according to claim 1, wherein the acrylic resin (A) is a resin obtainable by polymerizing an acrylic monomer having hydroxyl group as an essential monomer and other acrylic monomer and/or a vinyl monomer.

3. A coating method for repair comprising steps of:

conducting surface treatment at a part to be repaired;

providing undercoat; and

providing topcoat;

wherein a coating composition for the undercoat comprises;

(A) an acrylic resin having a hydroxyl value of 30 to 85 and a weight average molecular weight of 1000 to 30000, (B) a pigment, (C) resin fine particles, (D) a polyisocyanate compound, and (E) a curing catalyst;

wherein;

a ratio of isocyanate group in the (D) component to 1 equivalent of hydroxyl group in the (A) component is 2.0 to 4.0 equivalents;

content of the (B) component is from 100 to 500 parts by weight relative to 100 parts by weight of the resin solid matter; and

the (C) component is mixed so as to be from 0.1 to 5% by weight as a solid matter relative to the weight of the (B) component.