Material for absorbing aqueous fluids
AssigneeThe Dow Chemical Company
InventorsSyamalarao Evani, James H. Oswald, Thomas L. Staples, Brent T. Polak
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Abstract
Water absorbent compositions comprise a water swellable polymer which contains polymerized water-soluble monomers, water-insoluble monomers having a pendant hydrophobic moiety, and optionally, a crosslinking monomer. The polymer can be blended with a colloidal support such as colloidal silica. The compositions exhibit good water absorbency rates and high gel strengths.
Claims27
A composition capable of absorbing an aqueous liquid which composition comprises a functionally effective amount of a swellable addition polymer comprising, in polymerized form, (a) a major portion of at least one water-soluble monomer, (b) a minor portion of at least one water-insoluble monomer having a pendant hydrophobic moiety, and optionally, (c) a minor portion of a crosslinking moiety in an amount sufficient to provide gel strength to the polymer;
- which polymer is polymerized in the presence of at least a micelle forming amount of a surfactant composition containing at least one ionic surfactant;
- and which polymer is capable of undergoing hydrophobic association through hydrophobic groups of said polymer such that said polymer is swellable but not readily soluble in the presence of an aqueous liquid when said polymer is in intimate contact with an amount of surfactant, if any, which is less than that amount of surfactant which will solubilize said polymer in said aqueous liquid.
A process for providing a swellable addition polymer for use in a composition capable of absorbing an aqueous liquid, said process comprising providing (1) (a) a major portion of at least one water-soluble monomer, (b) a minor portion of at least one water-soluble monomer having a pendant hydrophobic moiety, and optionally, (c) a minor portion of a crosslinking moiety, and (2) polymerizing said monomers in an aqueous medium in the presence of at least a micelle forming amount of a surfactant composition containing at least one ionic surfactant such that the resulting polymer is capable of undergoing hydrophobic association through hydrophobic groups of said polymer, and wherein said polymer is swellable but not readily soluble in the presence of an aqueous liquid when said polymer is in intimate contact with an amount of surfactant, if any, which is less than that amount of surfactant which will solubilize said polymer in said aqueous liquid.
Dependencies are inferred from the claim text.