| 摘要 |
<p>1304077 Coating BOSTIK Ltd 11 May 1970 [12 May 1969] 22601/70 Heading B2E Substrates having a low critical surface tension of wetting and comprising polymeric material, polymer molecules of which have at least one hydrogen atom on a carbon chain of a repeating unit of the polymer molecule, are treated with ultra-violet radiation whilst photo-sensitizer material is present on the surface and an organic silicon compound applied to the surface to render the surface receptive to coatings. The term "low critical surface tension of wetting" is defined as up to 35 dynes per centimetre as determined by contact angle measurements. Polymeric materials mentioned are polyethylene, polypropylene, copolymers of ethylene and propylene alone or with a low percentage of a non-conjugated diene, e.g. a terpolymer of 64% ethylene, 34% propylene and 2% 1, 4-hexadiene, and fluorinecontaining polymers such as polyvinyl fluoride and polyvinylidene fluoride. Other surfaces which may be treated are moulded bodies of normally wettable resins, e.g. polyamides and polyesters which may contain residual amounts of mould release agents. The photo-sensitizer may be methylene chloride, trichloroethylene, chloroform, benzophenone, acetophenone, benzoin, 2-acetonaphthone, acenaphthene, fluorene. The photo-sensitizer may be applied to the surface of a substrate as a solution in a volatile solvent or as a liquid, or by melting and spraying fusible solid photo-sensitizer or by dusting on a powder of the photo-sensitizer. Alternatively, the photo-sensitizers may be uniformly distributed in the polymeric material of the substrate by milling it into the polymer prior to forming the substrate. When solid photo-sensitizers are used heat sufficient to fuse the photo-sensitizer may be applied. Excess photo-sensitizer may be removed from the surface after radiation, e.g. by wiping the surface with a solvent of the photo-sensitizer. Preferred organic silicon compounds are silanes having one or more alkoxy, aryloxy, acyloxy, amino or vinyl groups, applied as a liquid or as a solution, e.g. by spreading and wiping off the excess. The organic silicon compound may be present on the surface at the time of radiation, e.g. as a solution in a solvent which is itself a photo-sensitizer, e.g. ethylene dichloride. The solvent for the silane may contain water which converts the silane to the silanol. The treated substrates may be coated with epoxy, acrylic, nitrocellulose and oil-based paints, adhesives, e.g. epoxy resin and polyamides.</p> |
