| 摘要 |
<p>1,206,887. Porous coatings. ALGEMENE KUNSTZIJDE UNIE N.V. 16 May, 1968 [18 May, 1967], No. 23234/68. Heading B2E. A process for the manufacture of porous sheet material comprises applying to a substrate a liquid, homogeneous mixture of a polymer and an auxiliary substance which consists essentially of a solvent for the polymer, but which on cooling of the mixture precipitates therefrom, to a substrate, cooling the mixture to form a solid phase and then removing the auxiliary substance. A single substance for a mixture of substances may be used as an auxiliary substance. Suitable materials are lactams such as pyrrolidone, caprolactam and N- substituted lactams. Other similar materials are also specified. The auxiliary substance may conveniently be removed with water. The polymer material may be polyurethanes either alone or mixed with other polymers such as polyvinyl chloride or polyvinyl alcohol. Copolymers of ethylene and vinyl acetate and of ethylene and propylene may also be used and also other rubber like materials such as poly-2, 6-dimethylphenyleneoxide. The substrate may be fibre sheets and filament sheets or mats of polyamides, polyesters, polypropylene, polyvinyl alcohol, acrylic polymers, regenerated cellulose, wool, cotton, glass or mixtures of these.</p> |
