Patent ID: 6187841
Filing Date: 2001-02-13
Classification: C04B,C08F

Abstract:
A cement composition comprising cement, water, and a cement dispersant, said cement dispersant comprising as a main component a polycarboxylic acid type polymer (A) 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; said polycarboxylic acid type polymer (A) is 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): ##STR7##wherein R.sup.1 is a hydrogen atom or a methyl group, R.sup.2 O is one species or a mixture of two or more species of an oxyalkylene group having 2 to 4 carbon atoms, wherein when R.sup.2 O is a mixture of two or more species of oxyalkylene group having 2 to 4 carbon atoms, (R.sup.2 O).sub.m is a block or random copolymer, R.sup.3 is a hydrogen atom or an alkyl group of 1 to 5 carbon atoms, and m is the average addition mol number of oxyalkylene groups which is an integer in the range of 1 to 100;95 to 2% by weight of a (meth)acrylic acid monomer (b) represented by the following general formula (2): ##STR8##wherein R.sup.4 is a hydrogen atom or a methyl group and M.sup.1 is a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group, or an organic amine group;0 to 50% by weight of a monomer (c) which is different than (a) and (b) wherein said monomer (c) is selected from the group consisting of esters of aliphatic alcohols of 1 to 20 carbon atoms with (meth)crylic acid, unsaturated dicarboxylic acids, unsaturated amides, aromatic vinyls and unsaturated sulfonic acids, and which is copolymerizable with (a) and (b);wherein the total amount of (a), (b) and (c) is 100% by weight.