Patent GB-842556-A (GB)
Title: Improvements in or relating to the manufacture of polyethylene structure and coatings
IPC: C08L23/06
Filed: 1957-06-17
Abstract: A composition comprises an ethylene polymer of average molecular weight 15,000 to 3,000,000 and at least 0,1% of at least one ethylenically unsaturated aliphatic hydrocarbon said hydrocarbon having a softening temperature no higher than the lower temperature of the crystalline melting range of said ethylene polymer, a normal boiling point above the optical melting point of said polymer and a melt viscosity lower than that of said polymer at a temperature above 110 DEG C. and an average molecular weight which does not exceed 1500 to any considerable extent.  The hydrocarbon may be blended into the polymer before the formation of the polymer into a structure or it may be applied to the surface of the polymer structure e.g. from a liquid medium.  The aliphatic hydrocarbon may be straight or branched chain or a cycloaliphatic hydrocarbon and may be monomeric or polymeric.  It preferably contains at least 8 carbon atoms in a straight chain and may contain more than one ethylenie linkage per molecule.  The hydrocarbon may be nonene, decene, undecene, dodecene, hexadecene, eicosene, heneicosene, docosene, tricosene, triacontene, pentatriacontene, nonadiene, decadiene, undecadiene, dodecadiene, octadecadiene, eicosadiene, hexatriacontadiene, tetratetracontadiene, cyclopentylbutene, cyclohexylpropene, cyclohexylbutene or a low molecular weight polyethylene, polypropylene, polybutadiene or hydrogenated polybutadiene or natural rubber (balata).  The polymer may be polyethylene or copolymers of ethylene with minor amounts of propylene, butylene, isobutylene, styrene or vinyl acetate.  The compositions may be formed into structures such as filaments, rods, tubes or sheets or used to coat various base films but are used especially in the manufacture of polyethylene film.  The film may be subjected to "printability" treatment to increase the adhesion of polyethylene to printing inks such as by exposing the film to an electric discharge, raised temperatures, a temperature gradient or quenching or to chemical reagents e.g. chlorine sodium dichromate in sulphuric acid, ozone, nitrous oxide, a hypochlorite, hydrogen peroxide or nitric acid.  Specification 715,914, 722,875, 738,474, 755,738, 758,461, 794,616 and 810,723 are referred to.ALSO:Ethylene polymer and copolymer articles are coated with at least 0.1% of the weight of the said polymer, of at least one ethylenically unsaturated aliphatic hydrocarbon, said hydrocarbon having a softening temperature no higher than the lower temperature of the crystalline melting range of said ethylene polymer, a normal boiling point above the optical melting point of said polymer, a melt viscosity lower than that of said polymer at a temperature above 110 DEG C. and an average molecular weight which does not exceed 1500 to any considerable extent.  The polymer articles may then be subjected to a treatment for improving the adhesion to printing inks which may comprise subjecting the articles to an electric discharge, to raised temperatures, flames, temperature gradients, quenching or to chemical reagents such as halogens, halogen acids, ozone, hydrogen peroxide, nitrous oxide, a hypochlorite, nitric or sulphuric acids or sodium dichromate in sulphuric acid.  The hydrocarbon additive may be monomeric or polymeric and may contain more than one ethylenic linkage per molecule.  The hydrocarbons specified include nonene, decene, eicosene, tricosene, pentatriacontene, dienes such as decadiene and hexatriacontadiene, cyclopentylbutene, cyclohexylpropene, cyclohexylbutene and low molecular weight polyethylene, polypropylene, polybutadiene and hydrogenated polybutadiene and natural rubber (balata).  The compositions may be formed into structures such as filaments, rods, tubes or sheets.  The coating process may be carried out by applying the hydrocarbon additive from a liquid medium i.e. from a melt, dispersion or a solution, e.g. by dipping in a benzene solution or an aqueous dispersion. Specifications 715,914, 722,875, 738,474, 755,738, 758,461, 794,616 and 810,723 are referred to.