| 摘要 |
<p>A method of coating a polyolefin substrate comprises applying p thereto a continuous coating of an ethylene-vinyl acetate copolymer, applying a solution of a vinylidene chloride copolymer in an inert organic solvent to said coating and evaporating the solvent to leave a continuous vapour-impermeable vinylidene chloride copolymer coating thereon. The substrate may comprise a film, sheet, bottle, pipe, tube or laminate. Specified monomers used in forming the vinylidene chloride copolymers are vinyl chloride, acrylonitrile, methacrylonitrile, acrylic acid esters, methacrylic acid esters, maleic acid esters, fumaric acid esters, itaconic acid esters, methyl vinyl ketone, vinyl acetate, styrene, dichlorovinylidene fluoride, butadiene, chlorobutadiene, isoprene and vinyl pyridine. The ethylene-vinyl acetate copolymer may be applied by dipping, doctoring, spraying or gravure coating. Specified solvents for use with the vinylidene chloride copolymers are acetone, methyl ethyl ketone (or a mixture thereof with toluene), methyl iso-butyl ketone, cyclohexanone and tetrahydrofuran. The example describes the coating of the interior surface of polypropylene bottles, the second coating being a vinylidene chloride-acrylonitrile copolymer.</p> |
