| 摘要 |
<p>1,171,132. Microporous coating. MINNESOTA MINING & MFG. CO. 15 Sept., 1966 [16 Sept., 1965], No. 41339/66. Heading B2E. [Also in Divisions C3 and D2] A leather substitute comprises base, which may be coated, of a porous, air-permeable. water-laid sheet containing at least 50% of non-fibrous elasto-meric polyurethane and at most 50% of a fibre mixture uniformly distributed. The fibre mixture is a mixture of leather fibres, which constitute at least one third by weight of the fibre mixture and at least 10% by weight of the sheet, and staple non-leather fibres. The leather fibres may be tanned, and the non-leather fibres may be of nylon, polyethylene terephthalate, polypropylene, acetal copolymers, rayon, cellulose, glass or asbestos. The elastomeric polyurethane in emulsion form may be agglomerated by the action of alum, sodium carbonate, sodium chloride, karaya gum or locust-bean gum. Two or more layers of the material may be plied together with or without an adhesive, and the layers may then be of different compositions. In particular, a surface layer may have a higher proportion of leather fibres than a backing layer. Other ingredients may also be present, e.g. surfactants. plasticizers, dyes, pigments, other polymers or agents to provide resistance to light, heat or oxidation. The coating may be a microporous polymeric layer e.g. as in U.S. Patent 3,100,721.</p> |
