Patent TW-385327-B (TW)
Title: Water-soluble acrylic resin, resin composition containing the same for use in water-based coating composition, water-based coating composition and coating method by use of the same
Inventor: ENOMOTO MASASHI
IPC: C09D7/45
Filed: 1998-03-05
Granted: 2000-03-21
Abstract: A water soluble acrylic resin which is prepared by neutralizing with a neutralizing agent consisting of a basic compound an acrylic copolymer formed by copolylmerizing 1 to 30% by weight of (a) an alkylene oxide group-containing (meth)acrylate represented by the following general formula (I); where R is hydrogen atom or methyl group, R1 is hydrogen atom, alkyl group or acyl group, m is an integer of 1 to 200, provided that R1 is hydrogen atom and m is an integer of 2 to 200, and n is an integer of 2 or 3; 0.5 to 80% by weight of (b) a cyclic saturated hydrocarbon group-containing (meth)acrylate, 0 to 30% by weight of (c) a hydroxyl group-containing unsaturated monomer other than the monomer (a) and selected from the group consisting of hydroxyalkyl esters of (meth)acrylic acid having 2 to 8 carbon atoms, N-methylol acrylamide, allyl alcohol and epsilon-caprolactone-modified acrylic monomer, and 0 to 98.5% by weight of (d) other unsatureated monomer selected from the group consisting of alkyl esters of (meth)acrylic acid having 1 to 24 carbon atoms, vinyl aromatic compounds, N-vinyl pyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate, (meth)acrylonitrile and glycidyl (meth)acrylate, an acid group-containing monomer being contained as a comonomer in the monomer mixture of monomers (a), (b), (c) and (d) in an amount of 0.5 to 5% by weight; a resin composition used for a water-based coating composition and containing, as a vehicle component, the above water-soluble acrylic resin; a water-based coating composition containing, as major components, (A) at least one resin selected from the group consisting of a water-soluble resin and a water-dispersible resin and (B) a pigment, said pigment (B) being subjected to dispersion treatment with a water-soluble acrylic resin (C), which is prepared by neutralizing with a neutralizing agent consisting of a basic compound an acrylic copolymer formed by copolymerizing 3 to 30% by weight of (a) an alkylene oxide group-containing (meth)acrylate represented by the following general formula (I): where R is hydrogen atom or methyl group, R1 is hydrogen atom, alkyl group or acyl group, m is an integer of 1 to 100, provided that R1 is hydrogen atom and m is an integer of 2 to 100, and n is an integer of 2 or 3, 10 to 50% by weight of (b) a cyclic saturated hydrocarbon group-containing (meth)acrylate, and 20 to 87% by weight of (e) other unsaturated monomer mixture of (c) a hydroxyl group-containing unsaturated monomer other than the monomer (a) and selected from the group consisting of hydroxyalkyl esters of (meth)acrylic acid having 2 to 8 carbon atoms, N-methylol acrylamide, allyl alcohol and epsilon-caprolactone-modified acrylic monomer, (d) other unsaturated monomer selected from the group consisting of alkyl esters of (meth)acrylic acid having 1 to 24 carbon atoms, vinyl aromatic compounds, N-vinyl pyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate, (meth)acrylonitrile and glycidyl (meth)acrylate, and an acid group-containing monomer, followed by being mixed with the resin (A) to form a water-based coating composition, a mixing ratio between the pigment (B) and the water-soluble acrylic resin (C) being such that the pigment (B) is in the range of 50 to 150 parts by weight per 100 parts by weight of a resin solid content in the resin (C), and the water-soluble acrylic resin (C) being contained in the range of 5 to 35 parts by weight per 100 parts by weight of a total resin solid content of the resin (A) and the resin (C); a coating method comprising coating a base coat coating composition onto a substrate followed by coating a top clear coating composition, the above water-based coating composition being used as the base coat coating composition.