| 摘要 |
A water vapour-permeable leather substitute is made by forming a water vapour-impermeable sheet comprising particles or fibres of a water vapour-impermeable, non-extensible material embedded throughout a mass of a water vapour-impermeable, extensible material, stretching the sheet, and allowing it to relax. The extensible material, which constitutes 30-70 per cent of the weight of the sheet, may have little or no adhesion to the non-extensible component. The sheet may be stretched 10-50 per cent of its original dimensions in one or more directions. The extensible material may be a soft, thermoplastic polymer or elastomer such as polythene, chlorinated or chlorosulphonated polythene, ethylene-vinyl acetate copolymer, polymethyl acrylate, vinylidene chloride-acrylonitrile copolymer, polyamides, e.g. N-methoxymethyl adipamide, polyesters, polyvinyl acetals, e.g. the butyral and laural, plasticized polyvinyl chloride, polyisobutylene, natural rubber, neoprene, and butadiene copolymers with styrene and acrylonitrile. The particles may be pigments such as zinc oxide, titanium dioxide, talc, clay, diatomaceous earth, phenol- or urea-formaldehyde resin, polyamides, polyethylene terephthalate, or polytetrafluoroethylene. The fibres, which may be crimped nylon staple fibre, other specified polyamide fibres, polyethylene terephthalate, polyacrylonitrile, rayon, cotton, wool, may be first formed into an oriented or non-oriented web by carding, air-deposition or paper-making technique. The web is then combined with the extensible material by impregnation therewith, by pressing the fibrous mat into a film or sheet of the extensible material, by applying the extensible material in the form of a powder, or a liquid polymerizable compound which is later heated to bring about polymerization. Alternatively, fibres or particles of both materials are dispersed in an inert liquid such as water, and deposited to form a sheet which is pressed between heated rolls, or a mixture of fibres of the two materials may be formed into a carded web which is hot-pressed. The sheet may in any case be hot-pressed, e.g. between regenerated cellulose sheets or Bristol boards, before stretching, which may be effected by working by hand or on a tenter frame. Both particles and fibres may be present, e.g. nylon fibres and zinc oxide. Specification 557,544, [Group IV], is referred to.ALSO:A water vapour-permeable leather substitute is made by forming a water vapour-impermeable sheet comprising particles or fibres of a water vapour-impermeable, non-extensible material embedded throughout a mass of rubber, stretching the sheet, and allowing it to relax. The rubber, which constitutes 30-70 per cent of the weight of the sheet, may have little or no adhesion to the non-extensible component. The sheet may be stretched 10-50 per cent of its original dimensions in one or more directions. The particles may be pigments such as zinc oxide, titanium dioxide, talc, clay, diatomaceous earth, phenol- or urea-formaldehyde resin, polyamides, polyethylene terephthalate, or polytetrafluoroethylene. The fibres, which may be crimped nylon staple fibre, other specified polyamide fibres, polyethylene terephthalate, polyacrylonitrile, rayon, cotton, wool, may be first formed into an oriented or non-oriented web by carding, air-deposition, or paper-making technique. The web is then combined with the rubber by impregnation therewith, or by pressing the fibrous mat into a film or sheet of rubber. Alternatively, fibres or particles of both materials are dispersed in an inert liquid such as water, and deposited to form a sheet which is pressed between heated rolls, or a mixture of fibres of the two materials may be formed into a carded web which is hot-pressed. The sheet may in any case be hot-pressed, e.g. between regenerated cellulose sheets or Bristol boards, before stretching, which may be effected by working by hand or on a tenter frame. Both particles and fibres may be present e.g. nylon fibres and zinc oxide. Specification 557,544 [Group IV] is referred to. |
