| 摘要 |
<p>1,247,634. Laminates. E.I. DU PONT DE NEMOURS & CO. 19 March, 1970 [1 April, 1969], No. 13297/70. Heading B5N. [Also in Divisions B2 and C3] A vapour permeable, coriaceous, synthetic microporous sheet material comprises (1) a porous substrate of a synthetic polymeric material, reinforced with fibres, and having adhered thereto a microporous synthetic polymer coating (A) and (2) 0À02 to 5 mils of a non-porous vapour permeable finish (B) in adherence with the microporous coating (A), and consisting of a blend of (a) 20 to 80% by weight of a polyurethane obtained by reacting an aliphatic or cycloaliphatic diisocyanate with a hydroxy terminated polyester glycol of M.W. 500 to 3500 to form an isocyanate - terminated prepolymer which is then chain extended with an aliphatic or cycloaliphatic diamine, hydrazine or a monosubstituted hydrazine and (b) 80 to 20% by weight of cellulose acetate butyrate having a butyral content of 10 to 60% by weight and a viscosity of 1 to 20 poises as measured according to the ASTM-D-1343-54-T test procedure. The microporous sheet material (1) is suitably a porous substrate of non-woven web of polyester fibres that are impregnated with a polyurethane or blend of a polyurethane and polyvinyl chloride, the porous substrate having a microporous polymer coating of a polyurethane or similar blend. Alternatively an interlayer fabric may be placed between the porous substrate and the microporous coating. The finish composition may be applied from solution by spraying, roller coating, dipping, swabbing, brushing, padding or printing or it may be formed into a film and laminated to the surface of the microporous material. It is often preferably to have a finish of two separaet layers, the first layer containing a large amount of pigment and the second layer being clear or pigmented depending on the aesthetics required for the sheet material.</p> |
