| abstract |
Process for the preparation of copolymers which are wholly or predominantly composed of acrylamide and acrylic acid or methacrylic acid, in which 10-90 parts by weight of acrylamide (monomer I) 90-10 parts by weight are used to produce 100 parts by weight of the copolymer. Parts of acrylic acid and / or methacrylic acid (monomer II) or a salt of these acids with the cation M + ,n n n 0-40 parts by weight of another copolymerizable monomer andn n n 0-5 parts by weight of a copolymerizable, known crosslinker having two or more olefinic double bondsn n n polymerized in an alcohol with 1-4 C atoms in the manner of a precipitation polymerization in such a way that 10-90% by weight of the alcoholn n n 10-90% by weight of the total amount of monomers I to III andn n n 10-100% by weight of the crosslinking substance is submitted, the polymerization withn n n 10-100% by weight of the initiator starts and the remainder of the solvent, monomers, crosslinking agent and initiator, which complements one another, is metered in individually or as a mixture after the polymerization has started. The process products serve as highly effective thickeners for technical, cosmetic and pharmaceutical preparations. |