Patent ID: 6294015
Filing Date: 2001-09-25
Classification: C04B,C08F

Abstract:
A cement composition, comprising cement, a cement admixture, and water, wherein the cement admixture includes either or both of copolymer (A) and copolymer (B):copolymer (A) which includes constitutional unit (I) of general formula (1) below and constitutional unit (II) of general formula (2) below as essential constitutional units and may further include constitutional unit (III) of general formula (3) below, wherein the content of constitutional unit (III) is 45 weight % or less of copolymer (A), and wherein copolymer (A) may further include a further constitutional unit that is a monomer unit of a further monomer, wherein said further monomer is copolymerizable with monomers (a), (b) and (c), wherein constitutional unit (I) is a monomer unit of monomer (a), wherein constitutional unit (II) is a monomer unit of monomer (b) and wherein constitutional unit (III) is a monomer unit of monomer (c); andcopolymer salt (B) which is obtained by further neutralizing copolymer (A) with an alkaline substance;wherein general formula (1) is ##STR6##and general formula (2) is ##STR7##wherein: each of R.sup.1 O and R.sup.3 O denotes an oxyalkylene group with 2 to 18 carbon atoms or a mixture of two or more thereof, wherein the mixture may be formed by either block addition or random addition; each of m and n is an average molar number of addition of the oxyalkylene groups; both m and n are 10 or more and m and n are the same number; and each of R.sup.2 and R.sup.4 denotes an aliphatic or alicyclic hydrocarbon group with 1 to 30 carbon atoms, andwherein general formula (3) is ##STR8##wherein: R.sup.5, R.sup.6 and R.sup.7, independently of each other, denote a hydrogen atom, a methyl group or a (CH.sub.2).sub.p COOX group; X denotes a hydrogen atom, a monovalent metal, a divalent metal, an ammonium group or an organic amine group; and p denotes an integer of 0 to 2; wherein two COOX groups, if present, may form an anhydride.