Patent ID: 8119727

Claim:
A method for grinding a composition, comprising: admixing into the composition, as a grinding aid, at least one comb polymer to obtain a grinding stock; wherein the at least one comb polymer has a carbon backbone which bears polyether groups of formula A: *—U—(C(O)) k —X-(Alk-O) n —W A and functional groups B, which are present in the form of anionic groups at pH>12, and a salt thereof; and dry-milling the composition to obtain a cement preparation; wherein in formula A * indicates the binding site to the carbon backbone of the comb polymer, U represents a chemical bond or an alkylene group with 1 to 8 C atoms, X represents oxygen or an NR group, k is 0 or 1, n represents a whole number, the mean value whereof, based on the comb polymer lies in the range from 5 to 300, Alk represents C 2 alkylene, W represents a hydrogen, a C 1 -C 6 alkyl or an aryl residue or a group Y—Z, wherein Y represents a linear or branched alkylene group with 2 to 8 C atoms, optionally substituted with a phenyl ring, Z represents a 5- to 10-membered nitrogen heterocycle bound via nitrogen, optionally comprising 1, 2 or 3 additional hetero atoms, selected from oxygen, nitrogen and sulfur, wherein the nitrogen ring members may optionally be substituted with a group R′, and 1 or 2 carbon ring members may optionally be present as carbonyl groups, R represents hydrogen, C 1 -C 4 alkyl or benzyl, and R′ represents hydrogen, C 1 -C 4 alkyl or benzyl; and wherein in the carbon backbone, on a numerical average basis, a C 1 -C 4 alkyl group or a phenyl group is present on at least every fourth carbon of the carbon backbone, and at least one carbon atom which is not substituted with a polyether group (A) or functional group (B) is positioned between carbon atoms of the polymer backbone which bear a polyether group (A) or functional group (B) wherein the composition for grinding comprises at least one selected from the group consisting of cement clinker, granulated slag, pozzolan, fly ash, limestone and calcium sulfate.