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Water-soluble or water-swellable crosslinked copolymers

  • US 6,683,144 B2
  • Filed: 06/21/2002
  • Issued: 01/27/2004
  • Est. Priority Date: 01/11/2000
  • Status: Expired due to Term
First Claim
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1. A process for the preparation of a water-soluble or water-swellable crosslinked copolymer consisting essentially ofa) 1 to 50% by weight of a repeating structural unit of formula (1) embedded imagewhere n is an integer from 2 to 9,b) 49.99 to 98.99% by weight of repeating structural unit of the formula (3) embedded imagein which R3 is hydrogen, methyl or ethyl, Z is C1-C8-alkylene, and X is an ammonium ion, an alkali metal ion or an alkaline earth metal ion, andc) 0.01 to 8% by weight of crosslinking structures resulting from monomers having at least two olefinic double bonds selected from the group consisting of allyl acrylate, allyl methacrylate, allyl ethyl methacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, dipropylene glycol diallyl ether, polyglycol diallyl ether, triethylene glycol divinyl ether, hydroquinone diallyl ether, tetraallyloxyethane, tetraethylene glycol diacrylate, triallylamine, trimethylolpropane diallyl ether, methylene bisacrylamide, divinylbenzene, and mixtures thereof, said process comprising dissolving or dispersing the monomers corresponding to the repeating structural units of formulae 1 and 3 in a protic solvent, adding one or more the crosslinking structures of c) starting the polymerization by adding a free-radical—

  • forming compound.

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