Patent ID: 7208544

Claim:
A method for imparting flow-and-leveling properties to a water base coating comprising the step of: adding a trimethylsilyl group-containing copolymer obtained by copolymerizing 3-methacryloxypropyltrimethysilane (A) and/or a reactive monomer (B) selected from the group consisting of 3-methacryloxypropyltris(trimethylsiloxy)silane and vinyltris(trimethylsiloxy)silane with a (meth)acrylic acid ester (C) represented by the formula: wherein R 1 represents a hydrogen atom or methyl, and R 2 represents an alkyl group having 1 to 12 carbon atoms, and/or a (meth)acrylic acid ester (D) represented by the formula: wherein R 3 represents a hydrogen atom or methyl; R 4 represents an alkyl group having 1 to 18 carbon atoms; and n represents an integer of 2, 3 or 4, and acrylamide (E) represented by the formula: wherein R 5 and R 6 each represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and/or a (meth)acrylic acid ester (F) represented by the formula: wherein R 7 represents a hydrogen atom or methyl; R 8 represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms; m represents an integer of 2 to 100, and n represents an integer of 2, 3 or 4; and —(C n H 2n O) m — means that 2 to 100 units of only one kind of a glycol unit out of three kinds of the glycol units in which n is 2, 3 and 4 are present and that total 2 to 100 units of two or three kinds of the glycol units out of the three kinds of the above glycol units are present, and/or a (meth)acrylic acid (G) represented by the formula: wherein R 9 represents a hydrogen atom or methyl, wherein the above trimethylsilyl group-containing copolymer contains a trimethylsilyl group originating in the monomer (A) and/or the monomer (B) in a proportion of 2 to 64% by weight, a copolymerization unit originating in the (meth)acrylic acid ester (C) and/or the (meth)acrylic acid ester (D) in a proportion of 2% by weight or more, a copolymerization unit originating in the acrylamide (E) and/or the (meth)acrylic acid ester (F) and/or the (meth)acrylic acid (G) in a proportion of 5% by weight or more, and it has a number average molecular weight of 500 to 30000, to the water base coating.