Patent GB-848414-A (GB)
Title: Improvements in or relating to the cross-linking of hydrocarbons
IPC: G03F7/038
Filed: 1956-12-07
Abstract: Saturated hydrocarbons, e.g. polyolefines are cross-linked by irradiating with ultra-violet light of wavelength between 170 and 300, preferably between 200 and 300 millimicrons.  Polyolefines, e.g. mixtures from the cracking of petroleum, a Fischer-Tropsch devised paraffin or micro-crystalline wax, high and normal density polyethylene, polypropylene and polyisobutylene may be treated and the solid hydrocarbons may be in the form of sheets, foils, tubes, wire insulation, tapes, woven fabric, bottles or containers.  Carbon arc lamps or low pressure mercury vapour lamps, which may be fitted with filters and may be annular or otherwise suitably shaped are the source of actinic energy.  The cross-linking of gaseous hydrocarbons increases the molecular weight, liquids are substantially increased in viscosity or converted to solid form, and solids show increased resistance to temperature deformation and increased resistance to solvents, e.g toluene at elevated temperatures.  Activators such as diphenylamine, benzyl disulphide, acetophenone, benzoin and benzophenone, in amounts from 0,1 to 1% increase the speed of cross-linking and may be added by mixing in the liquid hydrocarbon, milling with the hot solid or the solid may be immersed in a solution of the activator.  Forms or photographic images may be reproduced on the surface by irradiating and removing the un-cross-linked portion by hot organic solvent.  In examples, the treatment of polyethylene (M.W. 20,000 and 40,000) as a sheet or slab, or in the form of a beaker, bottle or tube ; of high density polyethylene in a block, coated on a wire, or as single filament or a woven fabric ; polyisobutylene ; and polypropylene is described.  The reproduction of a photographic negative and positive, and a stencil upon a polyethylene coated surface is also described.ALSO:Saturated hydrocarbons are cross-linked by irradiating with ultra-violet light of wavelength between 170 and 300, preferably between 200 and 300 millimicrons.  Gaseous, liquid, or solid hydrocarbons such as oils, waxes, paraffins, and microcystalline waxes may be treated and the solid hydrocarbons may be in the form of sheets, foils, tubes, wire insulation, tapes, woven fabrics, bottles or containers.  Carbon arc lamps or low pressure mercury vapour lamps, which may be fitted with filters and may be annular or otherwise suitably shaped are the source of actinic energy. The cross-linking of gaseous hydrocarbons increases the molecular weight, liquids are substantially increased in viscosity and converted to solid form, and solids show increased resistance to temperature deformation and to solvents, e.g., toluene, at elevated temperatures.  Activators such as diphenylamine, benzyldisulphide, acetophenone, benzoin and benzophenone, in amounts from 0,1 to 1% increase the speed of cross-linking and may be added by mixing in the liquid hydrocarbon, milling with the hot solid or the solid may be immersed in a solution of the activator.  Forms or photographic images may be reproduced on the surface by irradiating and removing the un-cross-linked portion by hot organic solvent.  In examples a gaseous hydrocarbon mixture obtained from the cracking of petroleum oils; an oil fraction obtained from a petroleum refined neutral oil distillate; a Fischer Tropsch derived paraffin; and micro crystalline hydrocarbon wax are irradiated and a metal etching plate coated with microcrystalline wax was irradiated through a stencil, the unirradiated portion washed out to leave the metal exposed for etching.ALSO:Saturated hydrocarbons are cross-linked by irradiating with ultra-violet light of wavelength between 170 and 300, preferably between 200 and 300 millimicrons.  Gaseous, liquid and solid hydrocarbons such as oils, waxes, paraffins and microcrystalline waxes may be treated and the solid hydrocarbons may be in bulk or in the form of sheets, or surface coatings or dispersed in inert liquid such as water.  Carbon arc lamps or low pressure mercury vapour lamps, which may be fitted with filters and may be annular or otherwise suitably shaped are the source of activic energy. The cross-linking of the gaseous hydrocarbons increases the molecular weight, liquids are substantially increased in viscosity and converted to solid form, and solids show increased resistance to temperature deformation and solvents e.g. toluene, at elevated temperatures.  Activators such as diphenylamine, benzyl disulphides, acetophenone, benzoin and benzophenone in amounts from 0.1 to 1% increase the speed of cross-linking and may be added by mixing in the liquid hydrocarbon, milling with the hot solid or the solid may be immersed in a solution of the activator. Forms of photographic images may be reproduced on the surface by irradiating and removing the uncross-linked portion by hot organic solvent.  In examples a gaseous hydrocarbon mixture obtained from the cracking of petroleum oils, an oil fraction obtained from a petroleum refined neutral oil distillate; a Fischer-Tropsch derived paraffin; and microcrystalline hydrocarbon wax are irradiated and a metal etching plate coated with microcrystalline wax was irradiated through a stencil, and the unirradiated portion washed out to leave the metal exposed for etching.