Patent ID: 6258162
Filing Date: 2001-07-10
Classification: C04B,C08F

Abstract:
A cement composition, which comprises cement, water and a cement additive, wherein the cement additive includes copolymer (A) having polyalkylene glycol ester unit (I) of general formula (1) below as a repeating unit and carboxylic unit (II) of general formula (2) below as a repeating unit in the weight ratio (I)/(II)=(1.about.99)/(99.about.1), wherein a water/cement ratio is 10-70 weight % and wherein a ratio of the cement additive is 0.01-10 weight % in terms of solid content to the cement weight,wherein general formula (1) is: ##STR9##where:R.sup.1 O denotes an oxyalkylene group with 3 to 7 carbon atoms or a mixture of two or more thereof, wherein the mixture may be formed by either block addition or random addition;R.sup.2 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;R.sup.3 denotes a hydrocarbon group with 1 to 3 carbon atoms;n is an average molar number of addition of R.sup.1 O and denotes a number of 1 to 50;m is an average molar number of addition of R.sup.2 O and denotes a number of 51 to 300; andnot less than 80 mol % of the oxyalkylene groups (total of R.sup.1 O and R.sup.2 O) are oxyethylene groups;and wherein general formula (2) is: ##STR10##where:R.sup.4 denotes hydrogen or a methyl group; and.M denotes hydrogen, a monovalent metal, a divalent metal, ammonium, or an organic amine.