| 摘要 |
PROBLEM TO BE SOLVED: To develop excellent flow property and resistance against separation of materials by incorporating a copolymer having a polyalkyleneglycol ester unit and carboxylic acid unit in the repeating unit. SOLUTION: This cement additive contains a copolymer having the repeating unit containing a polyalkyleneglycol ester unit expressed by formula I and a carboxylic acid unit expressed by formula II. In the formula I, R1O is a 3-18C oxyalkylene group; R2O is a 2-18C oxyalkylene group in which >=50 mol% of R2O is an oxyethylene group; R3 is a 4-30C hydrocarbon group; n is 1 to 50; m is 5 to 300. In formula II, R4 is H or a methyl group; M is H, univalent metal, bivalent metal, ammonium or org. amine. The copolymer is obtd. by copolymn. of polyalkyleneglycol ester monomers and monomers containing carboxylic acid monomers corresponding to the respective structural units. The copolymer is added to cement by 0.01 to 10 wt.% calculated as a solid content of the cement weight.
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