Process of making water-absorbent, water-insoluble, cross linked fiber or film
AssigneeAllied Colloids Limited
InventorsAdrian S. Allen, David Farrar, Peter Flesher
Life of this patent
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Abstract
Water absorbent, water insoluble, cross linked polymer fibre or film can be made by dry extrusion of a solution of a substantially linear polymer formed from a water soluble blend of monoethylenically unsaturated monomers comprising a plasticizing monomer, evaporating the solvent and forming polymeric fibre or film plasticized by an external plasticizer, stretching the fibre or film while the external plasticizer remains in the fibre or film, and then cross linking the polymer.
Claims18
A process of making water-absorbent, water-insoluble, cross linked polymer fibre or film having a gel capacity of at least 50 g deionized water per gram comprising extruding into a gas atmosphere a 5 to 50 weight percent solution in a solvent of a substantially linear polymer formed of a water soluble bend of monoethylenically unsaturated monomers and thereby precipitating the polymer by evaporation of the solvent and forming polymeric fibre or film, stretching the fibre or film and then cross linking the polymer in the stretched fibre or film, and in which the polymer fibre or film is permanently plasticised by inclusion of a plasticising amount of plasticising monomer in the monomer blend and the said solvent comprises an external plasticiser that is dissolved in the polymer of the fibre or film and that plasticises the fibre or film throughout the stretching and that is present in the stretched fibre or film in a plasticising amount and that comprises a volatile liquid, and in which the volatile liquid is evaporated during or after the cross linking.
A process of making water-absorbent, water-insoluble, cross linked polymer fibre or film having a gel capacity of at least 50 g deionized water per gram comprising extruding into a gas atmosphere a 5 to 50 weight percent aqueous solution of a substantially linear polymer formed of a water soluble blend of a monoethylenically unsaturated monomers comprising carboxylic acid monomer and a plasticising amount of a plasticising monomer sufficient to permanently plasticise the fibre or film in a solvent and thereby precipitating the polymer by evaporation of the solvent and forming polymeric fibre or film, stretching the fibre or film to form stretched fibre or film, the water of said solvent comprising an external plasticiser that is dissolved in the polymer of the fibre or film and that plasticises the fibre or film throughout the stretching and that is present in the stretched fibre or film in a plasticising amount of at least 10% based on the dry weight of the fibre or film, collecting substantially non-tacky stretched fibre or film still containing external plasticiser, covalently cross linking the stretched fibre or film, and in which water is evaporated during or after the cross linking.
Dependencies are inferred from the claim text.