WATER-BASED COATING COMPOSITION AND METHOD OF FORMING MULTILAYERED COATING FILM

• US 20110300389A1
• Filed: 02/09/2010
• Published: 12/08/2011
• Est. Priority Date: 02/18/2009
• Status: Active Grant

• Current Assignee: Kansai Paint Company Limited
• Original Assignee: Kansai Paint Company Limited
• Inventors: Nakata, Munehiro, Kitagawa, Hiroshi, Takayama, Daisuke, Azuma, Tatsuya
• Granted Patent: US 8,993,673 B2
• Time in Patent Office: Days
• US Class Current: 428/423.1
• CPC Class Codes: B05D 1/36 Successively applying liquids or other fluent materials, e.g. without intermediate treatment
• CPC Class Codes: B05D 2401/20 Aqueous dispersion or solution
• CPC Class Codes: B05D 2420/01 first layer from the substrate side
• CPC Class Codes: B05D 2502/00 Acrylic polymers
• CPC Class Codes: B05D 2503/00 Polyurethanes
• CPC Class Codes: B05D 2520/00 Water-based dispersions
• CPC Class Codes: B05D 3/02 by baking B05D3/04 takes precedence
• CPC Class Codes: B05D 7/572 all layers being cured or baked together
• CPC Class Codes: B32B 2250/03 3 layers
• CPC Class Codes: B32B 2270/00 Resin or rubber layer containing a blend of at least two different polymers
• CPC Class Codes: B32B 2333/08 Polymers of acrylic acid esters, e.g. PMA, i.e. polymethylacrylate
• CPC Class Codes: B32B 2333/12 Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate
• CPC Class Codes: B32B 2375/00 Polyureas; Polyurethanes
• CPC Class Codes: B32B 2605/08 Cars
• CPC Class Codes: B32B 27/00 Layered products comprising a layer of synthetic resin fibrous or filamentary layer made of a synthetic resin B32B5/02; particulate layer made of a synthetic resin B32B5/16; foamed layer made of a synthetic resin B32B5/18
• CPC Class Codes: B32B 27/30 comprising vinyl (co)polymers; comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/308 comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/40 comprising polyurethanes
• CPC Class Codes: C08G 18/00 Polymeric products of isocyanates or isothiocyanates
• CPC Class Codes: C08G 18/0823 containing carboxylate salt groups or groups forming them
• CPC Class Codes: C08G 18/12 : using two or more compounds having active hydrogen in the first polymerisation step
• CPC Class Codes: C08G 18/3203 : Polyhydroxy compounds
• CPC Class Codes: C08G 18/44 : Polycarbonates
• CPC Class Codes: C08G 18/62 : Polymers of compounds having carbon-to-carbon double bonds
• CPC Class Codes: C08G 18/6225 : Polymers of esters of acrylic or methacrylic acid
• 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: C08G 18/6266 : Polymers of amides or imides from alpha-beta ethylenically unsaturated carboxylic acids
• CPC Class Codes: C08G 18/6511 : compounds of group C08G18/3203
• CPC Class Codes: C08G 18/66 : Compounds of groups C08G18/42, C08G18/48, or C08G18/52
• CPC Class Codes: C08G 18/6659 : with compounds of group C08G18/34
• CPC Class Codes: C08G 18/758 : containing two or more cycloaliphatic rings
• CPC Class Codes: C08J 2333/00 : Characterised by the use 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; Derivatives of such polymers
• CPC Class Codes: C08J 2333/08 : Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C08J 2333/10 : Homopolymers or copolymers of methacrylic acid esters
• CPC Class Codes: C08J 2375/04 : Polyurethanes
• CPC Class Codes: C08J 2433/00 : Characterised by the use 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; Derivatives of such polymers
• CPC Class Codes: C08J 2433/08 : Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C08J 2433/10 : Homopolymers or copolymers of methacrylic acid esters
• CPC Class Codes: C08J 2475/00 : Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
• CPC Class Codes: C08J 2475/04 : Polyurethanes
• CPC Class Codes: C08J 3/00 : Processes of treating or compounding macromolecular substances
• CPC Class Codes: C08J 3/203 : Solid polymers with solid and/or liquid additives
• CPC Class Codes: C08J 3/205 : in the presence of a continuous liquid phase
• CPC Class Codes: C08K 3/00 : Use of inorganic substances as compounding ingredients
• CPC Class Codes: C08K 3/20 : Oxides; Hydroxides graphene oxides C08K3/042
• 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: C08L 33/08 : Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C08L 33/10 : Homopolymers or copolymers of methacrylic acid esters
• CPC Class Codes: C08L 61/20 : Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen with aminophenols C08L61/04
• CPC Class Codes: C08L 75/00 : Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 75/04 : Polyurethanes
• CPC Class Codes: C09D 133/00 : Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
• CPC Class Codes: C09D 133/08 : Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C09D 133/10 : Homopolymers or copolymers of methacrylic acid esters
• CPC Class Codes: C09D 175/00 : Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
• CPC Class Codes: C09D 175/04 : Polyurethanes
• CPC Class Codes: C09D 5/00 : Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced electrically insulating plastics, resins or waxes H01B3/30; Filling pastes
• CPC Class Codes: C09D 5/002 : Priming paints C09D5/08 takes precedence
• CPC Class Codes: C09D 5/022 : Emulsions, e.g. oil in water
• CPC Class Codes: Y10T 428/31551 : Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]

Abstract

An object of the present invention is to provide an aqueous coating composition with excellent finished appearance and removability in bell cleaning, and a method for forming a multilayer coating film having excellent smoothness by a 3-coat-1-bake method including successively applying an aqueous first colored coating composition, an aqueous second colored coating composition, and a clear coating composition to a substrate, and heat-curing the resulting three layers of the multilayer coating film all at once. The present invention provides an aqueous coating composition containing an acrylic resin (A), a curing agent (B), and a urethane resin emulsion (C) with a weight average molecular weight of 2,000 to 50,000, the urethane resin emulsion (C) being prepared using constituent components containing a polyisocyanate component and a polyol component as starting materials, wherein the polyisocyanate component contains an alicyclic diisocyanate, and the polyol component contains a polycarbonate diol in an amount of 50 mass %, based on the total amount of the polyol component.

Claims

1. An aqueous coating composition comprising:

an acrylic resin (A);

a curing agent (B); and

a urethane resin emulsion (C) with a weight average molecular weight of 2,000 to 50,000,

the urethane resin emulsion (C) being prepared using a polyisocyanate component and a polyol component as starting materials;

the polyisocyanate component comprising an alicyclic diisocyanate, and

the polyol component comprising a polycarbonate diol in an amount of 50 mass % or more, based on the total amount of the polyol component.

2. The aqueous coating composition according to claim 1, wherein the acrylic resin (A) comprises a copolymer obtained by emulsion polymerization of a polymerizable unsaturated monomer mixture containing an alkyl(meth)acrylate monomer in an amount of 30 to 80 mass %, based on the total amount of the polymerizable unsaturated monomer mixture,

the alkyl group of the alkyl(meth)acrylate monomer having 4 to 14 carbon atoms.

3. The aqueous coating composition according to claim 1, wherein the curing agent (B) is at least one member selected from the group consisting of melamine resins (b-1), polyisocyanate compounds (b-2), blocked polyisocyanate compounds (b-3), and carbodiimide group-containing compounds (b-4).

4. The aqueous coating composition according to claim 1, wherein the polycarbonate diol is obtained by reacting a diol component and a carbonylating agent;

the diol component comprises a diol having 6 or more carbon atoms in an amount of 90 mass % or more, based on the total amount of the diol component; and

the diol having 6 or more carbon atoms comprises a cycloalkylene group-containing alicyclic diol having 6 or more carbon atoms.

5. The aqueous coating composition according to claim 1, wherein the proportions of the solids content of the acrylic resin (A), curing agent (B), and urethane resin emulsion (C) are 20 to 70 mass % of the acrylic resin (A), 5 to 20 mass % of the curing agent (B), and 10 to 50 mass % of the urethane resin emulsion (C), based on the total amount of the solids content of the acrylic resin (A), the curing agent (B), and the resin emulsion (C).

6. The aqueous coating composition according to claim 1, further comprising an oligomer (D) having a water tolerance of 10 or more, and a number average molecular weight of 200 to 1,500.

7. The aqueous coating composition according to claim 1, wherein the coating film formed using the aqueous coating composition has a water-swelling rate of 100% or less, and has an organic solvent-swelling rate of 300% or less.

8. An article coated with the aqueous coating composition of claim 1.

9. A method for forming a multilayer coating film, comprising sequentially performing the following steps (1) to (4) on a substrate:

step (1);

forming a first colored coating film by applying an aqueous first colored coating composition (X);

step (2);

forming a second colored coating film by applying an aqueous second colored coating composition (Y) to the first colored coating film formed in step (1);

step (3);

forming a clear coating film by applying a clear coating composition (Z) to the second colored coating film formed in step (2); and

step (4);

bake-drying the first colored coating film, the second colored coating film, and the clear coating film formed in steps (1) to (3) all at once,

wherein the aqueous first colored coating composition (X) is the aqueous coating composition of claim 1.

10. An article coated by the method of claim 9.