Donlar Corporation

Kim C Low

Larry P Koskan

Abdul R Meah

Anne M Atencio

Robert J Ross

Alfred P Wheeler

Disclosed are methods of producing super absorbing polymeric networks of polyaspartates from crosslinked polysuccinimide. In one preferred method aspect, polysuccinimide is first reacted with an organic crosslinking agent, preferably an organic base containing at least two primary amine groups to form crosslinked polysuccinimide. The crosslinked polysuccinimide is then hydrolyzed to a polymeric network of polyaspartate which demonstrates super absorbing capability in water and in saline solution. Alternative method aspects are disclosed in which super absorbing polymeric networks of polyaspartates are produced in a single reaction vessel by sequentially crosslinking polysuccinimide with organic crosslinking agent in an aqueous reaction mixture and then hydrolyzing the reaction product to produce a polymeric network of polyaspartate.

Superabsorbing polymeric networks

Disclosed are methods of producing high molecular weight, soluble, crosslinked polyaspartates from crosslinked polysuccinimide. In one preferred method aspect, polysuccinimide is first reacted with an organic crosslinking agent, preferably an organic base containing at least two primary amine groups to form a crosslinked polysuccinimide. The crosslinked polysuccinimide is then hydrolyzed to crosslinked polyaspartate which is soluble in polar solvents, preferably water, alcohol and mixtures thereof. Alternative method aspects are disclosed in which soluble crosslinked polyaspartates are produced in a single reaction vessel by sequentially crosslinking polysuccinimide with the organic crosslinking agent in an aqueous reaction mixture and hydrolyzing the product to crosslinked polyaspartate.

Soluble, crosslinked polyaspartates

Polyaspartic acid is produced by hydrolysis of anhydropolyaspartic acid that has been produced by thermal condensation polymerization of L-aspartic acid. Conversion in excess of 80 percent is achievable utilizing 'temperature vs. time' profiles.

Polyaspartic acid manufacture

.beta.-Polyaspartic acid having a weight average molecular weight of 1000 to 5000 produced by hydrolysis of anhydropolyaspartic acid exhibits a high degree of calcium carbonate and calcium phosphate inhibition.

Polyaspartic acid having more than 50% .beta. form and less that 50%

Polyaspartic acid having a weight average molecular weight of 1000 to 5000 is produced by hydrolysis of anhydropolyaspartic acid that has been produced by condensation polymerization of L-aspartic acid. Conversion in excess of 80 percent is achievable utilizing 'temperature vs. time' profiles.

Water soluble salts of a .beta.-polyaspartic acid, i.e., a polyaspartic acid having predominantly beta linkages in the amino acid residue chain thereof, are eminently well suited as dispersants for particulate matter in an aqueous medium.

Polyaspartic acid and its salts for dispersing suspended solids

Polyaspartic acid having a weight average molecular weight of 1000 to 5000 is produced by hydrolysis of anhydropolyaspartic acid. Anhydropolyaspartic acid is produced by condensation polymerization of L-aspartic acid. Greater than 80% conversion is achievable utilizing 'temperature vs time' profiles.

Manufacture of polyaspartic acids

.beta.-Polyaspartic acid having a weight average molecular weight of 1000 to 5000 produced by hydrolysis of anhydropolyaspartic acid, exhibits a high degree of calcium carbonate and calcium phosphate inhibition.

Polyaspartic acid as a calcium carbonate and a calcium phosphate

Polyaspartic acid as a calcium sulfate and barium sulfate inhibitor. Generally all forms of polyaspartic acid can be used. .beta.-polyaspartic acids are preferred.

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Alsip, IL, United States of America

Kim C Low