Patent GB-1040815-A (GB)
Title: Improved polyolefin films
IPC: C08J7/052
Filed: 1964-07-14
Abstract: Compositions for coating polyolefin structures comprise (a) a copolymer of 85 to 98 weight per cent of a vinyl ester in which the acyl group contains 2 to 8 carbon atoms and 15 to 2 weight per cent of an ethylenically unsaturated acid containing up to 6 carbon atoms, (b) 1 to 100% by weight of (a) of an alkali soluble polyester resin, and (c) 2 to 20% by weight of (a) of wax. The copolymer may be derived from vinyl acetate, propionate or butyrate, and acrylic, methacrylic, crotonic, isocrotonic, tiglic or angelic acid, or monoesters of maleic, fumaric, itaconic or citraconic acid.  The polyester may be derived from maleic modified rosin, fumaric modified rosin, phthalic anhydride, maleic anhydride or fumaric acid and ethylene, propylene, diethylene or triethylene glycols or glycerol. Specified waxes are carnauba, candelilla, esparto, montan, rice bran and castor wax, and oxidized microcrystalline and Fischer-Tropsch waxes.  The compositions may also contain finely divided inorganic solids such as colloidal silica.  The compositions may be coated on olefin polymer films from solutions in alkalis, e.g. aqueous ammonia. Examples describe compositions comprising vinyl acetate/ crotonic acid copolymers, maleic modified rosin polyesters and silica together with (I-V, VIII and IX) oxidized Fischer-Tropsch wax, (VI) carnauba wax and (VII) candellilla, esparto, oxidized microcrystalline, rice bran and montan waxes; and compositions comprising (X) a vinyl acetate/crotonic acid copolymer with a non-rosin dibasic acid/diethylene glycol polyester and carnauba wax or a fumaric modified rosin polyester and japan wax.ALSO:Polyolefin films are rendered heat sealable by coating with compositions comprising (a) a copolymer of a vinyl ester of an acid containing 2 to 8 carbon atoms and an ethylenically unsaturated acid having up to 6 carbon atoms, the copolymer containing 85 to 98 weight per cent of vinyl ester and 15 to 2 weight per cent of acid, (b) 1 to 100 per cent by weight of the copolymer of an alkali-soluble polyester resin, and (c) 2 to 20 per cent by weight of the copolymer of a wax.  The compositions may be applied from solutions in alkali, e.g. aqueous ammonia, by dipping, brushing, spraying, roll coating or gravure coating, to films of polyethylene, polypropylene or molecularly oriented polypropylene, which may have been surface treated with halogen, flame treatment or electronic treatment, or precoated with polyethylene imine to improve adhesion.  The copolymer may be derived from vinyl acetate, propionate or butyrate, and acrylic, methacrylic, crotonic, isocrotonic, tiglic or angelic acid or monoesters of maleic, fumaric, itaconic or citraconic acid.  The polyester may be derived from maleic modified rosin, fumaric modified rosin, phthalic anhydride, maleic anhydride or fumaric acid and ethylene, propylene, diethylene or triethylene glycols or glycerol.  Specified waxes are carnauba, candelilla, esparto, montan, rice bran and castor waxes, and oxidized microcrystalline and Fischer-Tropsch waxes.  The compositions may also comprise finely divided inorganic solids such as silica.  In examples oriented polypropylene films which have been treated with chlorine or (IV) precoated with polyethylene imine, are coated with compositions comprising vinyl acetate/crotonic acid copolymers, maleic modified rosin polyesters and silica together with (I-V, VIV and IX) oxidized Fischer-Tropsch wax, (VI) carnauba wax and (VII) candelilla, esparto, oxidized microcrystalline, rice bran and montan waxed; and compositions comprising vinyl acetate/crotonic acid copolymers with (X) non-rosin dibasic acid/diethylene glycol polyester and carnauba wax or a fumaric modified rosin polyester and japan wax.