Absorption rate of absorbent polymers by treating with glyoxal
AssigneeHercules Incorporated
InventorAlbert Richard Reid
Life of this patent
Estimating the term…
Abstract
Water-absorbent crosslinked polymers are improved in their wicking capacity by treatment of their surface with glyoxal. The polymer can be a polysaccharide--acrylamide graft copolymer or a polymer or copolymer of acrylamide and/or sodium acrylate or sodium methacrylate.
Claims11
A method of increasing the water or saline solution absorption rate of a water-insoluble, crosslinked polymer selected from the class consisting of acrylamide homopolymer, copolymers of acrylamide and a second vinyl monomer copolymerizable therewith, homopolymers of sodium acrylate, homopolymers of sodium methacrylate, and polysaccharides grafted with copolymers of acrylamide and a second vinyl monomer copolymerizable therewith, which method comprises applying to the surface of particles of said polymer about 0.2 to 5% by weight of glyoxal.
A method of increasing the water or saline solution absorption rate of a water-insoluble, crosslinked polymer selected from the class consisting of acrylamide hompolymer, copolymers of acrylamide and a second vinyl monomer copolymerizable therewith, homopolymers of sodium acrylate, homopolymers of sodium methacrylate, and polysaccharides grafted with copolymers of acrylamide and a second vinyl monomer copolymerizable therewith, which method comprises forming a slurry of particles of the crosslinked polymer in a nonsolvent liquid, adding to said slurry glyoxal in an amount equal to about 0.2 to 2% by weight of the polymer, adjusting the pH of the slurry to about 5.5 to 5.6, removing the polymer from the slurry and drying at about 50 to 75.degree. C. to remove residual slurrying liquid.
An acrylic polymer selected from the class consisting of
- a. homopolymers of water-soluble acrylic acid salts,
- b. homopolymers of water-soluble methacrylic acid salts,
- c. homopolymers of acrylamide,
- d. copolymers of acrylamide and one of the salts specified in (a) and (b) in any proportion, and
- e. graft copolymers of a water-insoluble, water wettable polysaccharide, acrylamide and a second vinyl polymer copolymerizable therewith, said acrylic polymer being crosslinked via a divinyl monomer and being in particulate form and having its particle surfaces treated with about 0.2 to 5% by weight of glyoxal.
A graft copolymer of cellulose, acrylamide and an acrylic acid salt crosslinked via methylene bis-acrylamide and comprising about 10 to 90% by weight of cellulose, said copolymer being in particulate form and having its particle surfaces treated with about 0.2 to 2% by weight of glyoxal.
A copolymer of acrylamide and a water-soluble acrylic acid salt in any proportion, said copolymer being crosslinked via methylene bis-acrylamide, being in particulate form and having its particle surfaces treated with about 0.2 to 2% by weight of glyoxal.
Dependencies are inferred from the claim text.