FINISHING PROCESS FOR LEATHER AND LEATHER SUBSTITUTES

摘要

1465618 Finishing leather ROHM & HAAS CO 11 June 1974 [9 July 1973] 25781/74 Heading B2E A finishing process for leather or leather substitutes comprises applying to the surface of the leather or leather substitute, e.g. by spraying a polymer latex containing a crosslinkable polymer and a blowing agent which is either a solvent blowing agent in which the uncrosslinked polymer exhibits a swell ratio of 1 to 7 or a chemical blowing agent, foaming and drying the foamed coating, crushing the foamed, coating at least in selected areas, applying heat and pressure to cure the coating and adhere it to the substrate and applying' a finish coating. Suitable substrates include leather splits, low grade leather, textiles, non-woven webs, poromeric and plastics materials. Suitable finish coats contain one or more of nitrocellulose, polyurethane modified nitrocellulose, a polyurethane, polyvinyl chloride; an acrylic polymer or cellulose acetate butyrate. One or more finish layers may be applied. Many monomers which may be used to prepare the latex copolymers are specified. They include acrylic, methacrylic and ethacrylic acid and derivatives thereof, itaconic acid, aconitic acid, crotonic acid, citraconic acid, maleic acid, fumaric acid, alpha-chloroacrylic acid, cinnamic acid, menaconic acid, vinyl acetate, acrylamide, styrene, vinyl-toluene, methacrylamide, 6-(3-buteryl)-2, 4-diamino-striazine, acrylonitrile, methacrylonitrile, acrolein methacrolein, 3, 4-epoxy-1-butene, acrolein diethyl acetal, acrolein dimethyl acetal allylidene diacetate and methallylidene diacetate. Many more such monomers are listed. Preferred polymers are emulsion polymers which may include surfactants. The finish compositions may be clear or contain dulling agents, pigments and dyes. Suitable pigments include clay, TiO 2 , CaCO 3 , blanc fixe, finely divided aluminium, colour lakes and tricosal oxides. The finish compositions may be applied by brushing, swabbing, spraying, curtain coating or dip coating. The products may be used in luggage, upholstery, shoes and jackets. The foamable composition may include clay, mica, calcium carbonate bentonite and silica as fillers. Suitable pigments include carbon black, iron oxide, anatase and TiO 2 . Suitable waxes include polyethylene waxes.