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US 5,478,894 AGranted
Process for preparing crosslinked water absorbent resins
AssigneeHoechst Celanese Corporation
InventorsWilliam G. Chiang, Joy L. McCrickard
Life of this patent
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Abstract
This invention is directed to a recurring polymeric moiety of the following formula: ##STR1## wherein R is independently selected from hydrogen and C.sub.1 to C.sub.4 alkyl; Y is independently selected from O and NH; and X is independently selected from Cl, F, Br, I, NO.sub.3, HSO.sub.4 and H.sub.2 PO.sub.4. Polymers of the above structure may be crosslinked by treating the polymer with a base and heating it.
Claims7
A method of preparing a water-insoluble, partially cross-linked, hydrogel-forming polymer which comprises:
- (a) polymerizing a first ethylenically unsaturated water soluble monomer having at least one hydrophilic carboxy group in the presence of a second ethylenically unsaturated monomer of the formula:
- ##STR5## wherein:
- said first ethylenically tinsaturated water soluble monomer is present in an mount of at least 50% by weight;
- R is independently selected from H and C.sub.1 to C.sub.4 alkyl;
- Y is independently selected from O and NH;
- and
- X is independently selected from Cl, Br, F, I, NO.sub.3, HSO.sub.4 and H.sub.2 PO.sub.4 ;
- (b) contacting the polymerization product of step (a) with a base to convert the terminal portion of said second monomer to an epoxy group;
- and
- (c) heating said polymerization product to effect crosslinking of said polymerization product.
7 more elements
Dependencies are inferred from the claim text.