Cement mix to improve settling time.

摘要

A polymer comprising side chains of which at least 10% by weight can be broken in an alkaline medium at a pH of 8 to 14 to 20 C, such side chains attached to the backbone of said polymer by ester groups being optionally amide and / or imide groups, whereby said polymer comprises a mol% of structural unit a of formula I ** ** formula b mol% of structural unit B of formula II ** ** formula c% mole of structural unit C of formula III ** ** formula d mol% of structural unit D of formula IV and formula ** ** e mol% of structural unit e of formula V ** ** formula wherein each R1, independently of each other, represents a hydrogen atom or a methyl group or mixtures thereof; M representaun hydrogen atom, a metal cation, an ammonium cation or an organic ammonium cation or mixtures thereof; R2, R20 and R3 independently of each other, represents a cycloalkyl alkyl group or C1-C12, one C2C12o (R7O) zR8 hydroxyalkyl group in which O represents an oxygen atom, R7 represents an alkylene group C2C3 or mixtures, R8 represents a hydrogen atom, alkyl group or cycloalkyl C1C12, a C2-C12 hydroxyalkyl group, or an unsubstituted or substituted aryl group and z represents a number from 1-250, whereby R2, R3 and R20 can be mixtures thereof; R4 and R5 represent, independently of one another, a hydrogen atom or a substituent as defined for R2, and R4 and R5 may together a ring structure of which is part the N form, this ring structure may further contain other heteroatoms as further nitrogen, sulfur or oxygen, or mixtures thereof; R6 is a single bond or a methylene group, a, b, c, d and e represent numbers where the sum of a + b + c + d + e = 100 and b is a number from 10-90, c is a number from 0-85, d is a number from 0-50 and e is a number from 0-10 and is 100- (b + c + d + e), whereby a is at least 5.