Forming superabsorbent polymer
AssigneeSolutia Inc.
InventorYueting Chou
Life of this patent
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Abstract
A method of preparing superabsorbent polymer as crosslinked polyaspartate salt by reacting polysuccinimide dissolved in organic solvent with crosslinker and reacting the polysuccinimide in situ with neat or a solution of alkali metal hydroxide to form the crosslinked salt.
Claims13
A method of preparing crosslinked polyaspartate salt which comprises:
- i) reacting polysuccinimide dissolved in organic solvent with crosslinker to form crosslinked polysuccinimide;
- and
- ii) reacting the polysuccinimide of i) in situ with neat or a concentrated solution of alkali metal, alkaline earth metal or ammonium hydroxide to form the crosslinked salt.
A method of preparing solid crosslinked polyaspartate salt which comprises:
- i) dissolving polysuccinimide in organic solvent;
- ii) reacting the dissolved polysuccinimide with crosslinker;
- and then
- iii) hydrolyzing the reaction product of ii) in situ to form the precipitated salt;
- and then
- iv) isolating the precipitated solid salt from the organic solvent.
A crosslinkable, hydrolyzable composition comprising:
- i) polysuccinimide (PSI) dissolved in organic solvent;
- ii) crosslinker for PSI;
- and
- iii) metal hydroxide in neat form or as aqueous solution.
In the process for preparing crosslinked polyaspartate salt or acid by hydrolyzing polysuccinimide crosslinked in an organic solvent reaction medium, the improvement wherein hydrolysis occurs in situ in the organic solvent reaction medium.
Dependencies are inferred from the claim text.