Back to results
US 5,955,549 AGranted
Crosslinked poly(amino acids) and method of preparation
OwnerChing-Jen Chang, Graham Swiftinventors
Life of this patent
Estimating the term…
Abstract
Crosslinked poly(amino acids) useful as superabsorbent polymers and an improved process for preparing the crosslinked poly(amino acids) is disclosed. Use of polyaziridine and polyepoxide crosslinkers allows the production of superabsorbent polymers that is free of special handling steps required to process hydrogel materials using conventional preparation methods.
Claims11
A crosslinked poly(amino acid) having the stoichiometric formula:
- A!.sub.x B!.sub.y,
- wherein A represents repeat units of backbone polymer structure 1! and B represents crosslinking units of structures 2! or 3! randomly distributed among the units of polymer structure 1! through ester linkage formation with a carboxylate group of radical R, ##STR6## wherein x represents weight percent of A units and y represents weight percent of B units, based on weight of combined A and B units;
- wherein x is from 80 to 99.9 weight percent and y is from 0.1 to 20 weight percent;
- m is 0, 1 or 2;
- n is from 20 to 20,000;
- R is a radical selected from the group consisting of one or more of --C(.dbd.O)OM, --CH.sub.2 C(.dbd.O)OM and --CH.sub.2 CH.sub.2 C(.dbd.O)OM, and M is selected from the group consisting of one or more of H, alkali metal ion and alkaline earth metal ion;
- X is O, S or N;
- R.sup.1 is a residue of a di-, tri- or tetrafunctional group selected from (C.sub.1-C.sub.4)alkylene, aryl, arylalkyl and methylene ether of a (C.sub.6 -C.sub.5)polyphenol, (C.sub.2 -C.sub.6)alkanepolyol or poly(alkylene glycol);
- each R.sup.2 is H when X is O or S and each R.sup.2 is independently H or (C.sub.1 -C.sub.3)alkyl when X is N;
- R.sup.3 is a residue of a di-, tri- or tetrapropionate ester of a (C.sub.2 -C.sub.6)alkanepolyol;
- a is 0 or 1;
- and b is 1, 2 or 3.
9 more elements
A process for preparing crosslinked poly(amino acids) comprising:
- (a) contacting an aqueous solution of poly(aminoacid) with 0.1 to 20 percent by weight of crosslinker, based on weight of poly(amino acid), in a reaction mixture at a pH from 3 to 7, wherein the poly(amino acid) is selected from the group consisting of one or more of poly(aspartic acid) and poly(glutamic acid) and the crosslinker is selected from the group consisting of one or more crosslinkers of formula 4! and 5!, ##STR7## where X.sup.1 =O, S or NR.sup.2, R.sup.1 =a residue of a di-, tri- or tetrafunctional group selected from (C.sub.1 -C.sub.4)alkylene, aryl, arylalkyl and methylene ether of a (C.sub.6 -C.sub.15)polyphenol, (C.sub.2 -C.sub.6)alkanepolyol or poly(alkylene glycol);
- R.sup.2 =H or (C.sub.1 -C.sub.3)alkyl,
- R.sup.3 =a residue of a di-, tri- or tetrapropionate ester of a (C.sub.2 -C.sub.6)alkanepolyol,
- a=0 or 1, and
- b=1, 2 or 3,
- (b) removing water from the reaction mixture,
- (c) subjecting the reaction mixture to a heat treatment, and
- (d) recovering the crosslinked poly(amino acid) as a solid.
5 more elements
Dependencies are inferred from the claim text.