American Colloid Company

Barbara R Regan

William C Alexander

Mark Anderson

A method of preparing a solid water absorbing resin including mixing a monomer solution of (A) acrylic acid neutralized 70-100 mole percent; and (B) a water-miscible to water-soluble polyvinyl monomer in a combined concentration of at least 30 wt. %; with water to form a mixed monomer solution, and adding a thermal initiator and a redox initiator to the mixed monomer solution to form an initiated mixed monomer solution, and wherein the mixed monomer solution is at a temperature below the decomposition temperature of the thermal initiator when the thermal initiator is added to the mixed monomer solution and wherein the temperature of the mixed monomer solution is high enough such that addition of the redox initiator thereto causes sufficient polymerization of the monomers to raise the temperature of the initiated mixed monomer solution to a level sufficient that the thermal initiator decomposes sufficiently to provide, together with the redox initiator, substantially complete polymerization.

Process for preparing water-absorbing resins

Surface treating water-absorbent resins with a polyquaternary amine substantially increases both the rate of water absorption and the quantity of water absorbed and retained by the resin. In addition to improved water absorbing properties, the surface-treated resins maintain the necessary 'dry feel' required for most applications.

Surface treated absorbent polymers

Improved water-absorbing, crosslinked acrylate resins are prepared by aqueous polymerization of (A) acrylic acid neutralized 70 to 100 mole percent for example with ammonia and/or caustic alkali and/or an amine; with (B) acrylamide in a mole ratio of 70 to 100 mole percent (A) to 30:0 mole percent (B); and (C) a water miscible or a water soluble polyvinyl monomer in the presence of (D) a styrene-maleic anhydride copolymer, neutralized 70 to 100 mole percent for example with ammonia, and/or caustic alkali and/or an amine, in an amount of 1% to 25% based on the weight of acrylic acid or acrylate, such that the amount of (C) is 0.001 to 0.6 weight percent based on the total weight of (A), (B), (C) and (D). In addition, surface treating the water-absorbing crosslinked acrylate resins with a polyquaternary amine substantially further increases both the rate of water absorption and the quantity of water absorbed and retained by the resin. The untreated and the surface-treated resins also maintain the necessary 'dry feel' required for most applications.

Water absorbent resins prepared by polymerization in the presence of

Water absorbing, cross-linked acrylate resin copolymers are prepared by aqueous polymerization of (A) acrylic acid neutralized 70 to 100 mole percent for example with ammonia, and/or caustic alkali and/or an amine; with (B) styrene and/or methyl methacrylate in an amount of 1% to 25% based on the weight of acrylic acid or acrylate, and (C) acrylamide in a mole ratio of 70 to 100 mole percent (A) to 30:0 mole percent (C); and (D) a water miscible or a water soluble polyvinyl monomer in an amount of 0.001 to 0.3 weight percent based on the total weight of (A), (B), (C) and (D).

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Glenview, IL, United States of America

Barbara R Regan