Patent GB-920860-A (GB)
Title: Surface treatment of films and other polymeric shaped structures
IPC: C08J9/36
Filed: 1961-06-15
Abstract: A process for modifying the surface characteristics of films and other polymeric shaped structures to improve, for example, their receptiveness to dyes and their adhesiveness, comprises subjecting the surface of such a structure to the action of an electrical discharge having an energy level below 15 electron volts in a gaseous atmosphere containing as an essential ingredient the vapour of an organic compound having a vapour pressure of at least 1 mm. of mercury at 60 DEG C., said organic compound being a polymerizable compound, a non-polymerizable organic compound having replaceable hydrogen atoms, or a perhalohydrocarbon having a bond dissociation energy for the carbon-halogen bond below 100 kilo-calories.  The surface is preferably exposed to the discharge for at least 1x10-5 second by passing the structure, preferably a film, or foamed structure, between spaced positive and negative electrodes with a gap of 0,005 to 0,25 inch.  The voltage may be from 100 to 100,000, the frequency from 60 to 500,000 cycles per second, and the current from 0,3 to 2,1 RF amperes.  Specified polymeric materials are the polymers or polycondensates of perfluorocarbons (e.g. tetrafluoroethylene/hexafluoropropene copolymer), vinyl fluoride, vinylidene fluoride, vinyl chloride, vinylidene chloride, vinyl acetate, ethylene, propylene, butene-1, styrene, ethylene terephthalate, amides, acrylates, methacrylates, acetals, spiroacetals, urethanes and carbonates; regenerated cellulose, cellulose acetate and cellulose ethers; coumaroneindene resins, epoxy resins, phenol-aldehyde resins, urea-formaldehyde resins, melamineformaldehyde resins, isocyanate resins and protein plastics. The organic agent may be glycidyl methacrylate, methyl methacrylate, acrylonitrile, cyclopentadiene, styrene, p-chlorostyrene, vinyl butyl ether, methyl vinyl ketone, vinyl acetate, 1-hexene and N-vinyl-2-pyrrolidone; xylene, hexane, cyclohexane, carbon tetrachloride, chloroform, tetrahydrofurane, diethylsulphone and tetraisopropyl titanate.  Nitrogen or carbon dioxide may also be present as a carrier gas.  The flow of the carrier gas/organic vapour mixture to the electrodes may be 1/2 to 10 cubic feet per minute. The permanency of the adhesiveness effect produced on the surfaces of perfluorocarbon polymer structures by the process of the invention is greatly improved by heating the surfaces to at least 150 DEG C. for at least one hour and/or by coating the freshly treated surfaces with a polymeric, and preferably an adhesive polymeric, coating.  The heat treatment may also be used to restore the adhesiveness of the electrically treated surfaces after prolonged storage of the structures before use.  Specification 829,600 is referred to.ALSO:A process for modifying the surface characteristics of polymeric shaped structures comprises subjecting the surface of such a structure to the action of an electrical discharge having an energy level below 15 electrons volts in a gaseous atmosphere containing as an essential ingredient the vapour of an organic compound having a vapour pressure of at least 1 mm. of mercury at 60 DEG C, said organic compound being a polymerizable compound, a non-polymerizable organic compound having replaceable hydrogen atoms, or a perhalohydrocarbon having a bond dissociation energy for the carbon halogen bond below 100 Kilocalories.  The surface is preferably exposed to the discharge for at least 1 X 10-5 second by passing the structure, preferably a film between spaced electrodes with a gap of 0,005 to 0,25 inch.  The voltage may be from 100 to 100,000 and frequencies from 60 to 500,000 cycles per second, and the current from 0,3 to 2,1 RF amperes. Specified polymeric material are the polymers of perfluorocarbons, vinyl fluoride, vinylidene fluoride, vinyl chloride, vinylidene chloride, vinyl acetate, ethylene, propylene, butene-1, styrene, ethylene terephthalate, amides, acrylates, methacrylates, acetals, spiroacetals, urethanes and carbonates; regenerated cellulose, cellulose acetate and cellulose ethers; counarone indene resins, epoxy resins, phenolaldehyde resins, urea-formaldehyde resins, melamine formaldehyde resins, isocyanate resins and protein plastics. The organic agent may be glycidyl methacrylate, methyl methacrylate, acrylonitrile, cyclopentadine, styrene, p-chlorostyrene, vinyl butyl ether, methyl vinyl ketone, vinyl acetate, 1-hexane and N-vinyl-2-pyroolidone; xylene, hexane, cyclohexane carbon tetrachloride, chloroform, tetrahydrofurane, diethylsulphone and tetraisopropyl titanate. Nitrogen or carbon dioxide may also be present.