GB1353246A - Poromeric materials - Google Patents

Abstract

1353246 Laminates L G RAY JNR and E J JACOB 19 April 1971 [19 March 1970 23 July 1970] 23411/71 Heading B5N [Also in Division C3] Laminates comprise textile fabrics and microporous moisture vapour permeable sheets having micropores containing shrunken material which are prepared by forming a layer of a composition comprising a dispersion in a liquid medium of a reversibly swellable and deswellable material that is highly swollen to at least twice its dry size by having absorbed therein a swelling agent and deswellable to less than half its swollen size by removal of the swelling agent therefrom. The liquid medium is a liquid filmforming polymer, has dissolved therein a filmforming polymer or comprises a dispersion of a film-forming polymer in a plasticizer for the polymer. The layer is dried, cured if necessary and the swelling agent removed from the swellable material by heating and thereby deswelling the swollen material. The swellable material may be a cellulosic compound, a polyoxyethylene resin, a natural gum, sodium alginate, dextrin or corn starch in which cases the swelling agent is water. The swelling agent may be a synthetic elastomer, e.g. a butadiene/acrylonitrile copolymer, and the swelling agent non- aqueous, e.g. the same solvent as that used to dissolve the film forming polymer. Examples relate to polyvinyl chloride plastisols as the film former with aqueous swollen materials, e.g. carboxymethyl cellulose, guar gum, sodium alginate or a polyoxyethylene resin and a plastisol swollen acrylonitrile/butadiene copolymer. Other examples relate to polyurethane resins using similar swellable materials and swelling agents. The microporous sheets may be laminated to the textile backing using as adhesive, a material of the same composition as that used to form the microporous sheet.