| 摘要 |
A copolymer is disclosed which acts as a thickening agent for aqueous preparations having a pH of more than 5.5. The copolymer is obtainable by emulsion polymerization in an aqueous medium, at a pH of 2.5 to 5, in the presence of an initiator forming free radicals, at a temperature of 60 DEG to 95 DEG C. of 10 to 50% by weight of acrylic or methacrylic acid, 25 to 75% by weight of a nonionic vinyl monomer and 2 to 50% by weight of a macromonomer of the formula CH2=CR-CH2-O-(CnH2nO)a(CmH2mO)b(CpH2pO)cH wherein R is H or CH3 n, p are the same or different and in each case are 2 or 3, with the proviso that n and p have a value of not more than 2.3 in the average molecule, m=a whole number from 12 to 18 a=10 to 100, b=2 to 10, c=0 to 10 and wherein the sum of the monomers amounts to 100% by weight.
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