Patent ID: 6376581
Filing Date: 2002-04-23
Classification: C04B,C08F

Abstract:
A cement composition comprising at least cement, water, and a cement dispersant, said cement dispersant comprising as a main component a polycarboxylic acid type polymer (A) obtained by copolymerizing:5 to 98% by weight of an (alkoxy)polyalkylene glycol mono(meth)acrylic ester monomer (a) represented by the following general formula (1): â€ƒwherein R1 is a hydrogen atom or a methyl group, R2O is one species or a mixture of two or more species of an oxyalkylene group having 2 to 4 carbon atoms, wherein when R2O is a mixture of two or more species of oxyalkylene group having 2 to 4 carbon atoms, (R2O)m is a block or random copolymer, R3 is a hydrogen atom or an alkyl group of 1 to 5 carbon atoms, and m is the average addition mol number of oxyalkylene group; 95 to 2% by weight of a (meth)acrylic acid monomer (b) represented by the following general formula (2): â€ƒwherein R4 is a hydrogen atom or a methyl group and M1 is a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group, or an organic amine group; and 0 to 50% by weight of a monomer (c) which is different than (a) and (b), and which is copolymerizable with (a) and (b); wherein the total amount of (a), (b) and (c) is 100% by weight, or salt thereof, wherein said polymer (A) has a weight average molecular weight in the range of 10,000 to 500,000 in terms of polyethylene glycol determined by gel permeation chromatography, and has a value determined by subtracting the peak top molecular weight from the weight average molecular weight in the range of 0 to 8,000.