Improved polythene compositions

Abstract

Abstract A composition for the production of solid films on surfaces comprises a paste-like dispersion of polyethylene in a solution of one or more normally solid film-forming materials dissolved in a volatile liquid of one or more components, of which at least the higher boiling component or components are capable of dissolving the polyethylene only at an elevated temperature at atmospheric pressure, the film-forming materials being in an amount of from 2 to 50 per cent by weight of the polyethylene and being capable of forming solid solutions with polyethylene. The polyethylene may be dispersed mechanically in the form of a fine powder or a solution of it in a fraction of the volatile liquid may be added, hot or cold, to a solution of the film-forming material in the remainder of the solvent. Films are obtained by evaporating a part of the solvent at a temperature greater than 60 DEG C. Suitable volatile liquids are benzene, toluene, xylene, tetrahydronaphthalene, petroleum ether, chlorobenzene and trichloroethylene. Chloroform or carbon tetrachloride may be added as a diluent. Suitable film-forming materials include poly-styrene, hydrogenated polystyrene, halogenated polythene, polyisobutylene of molecular weight greater than 60,000, rubber, cyclized rubber and synthetic rubbers such as those known as "Neoprene," "G.R.S.," and butyl rubber. Modifying ingredients, which together with the film-forming material amount to 5 to 30 per cent by weight of the polyethylene, may be added and may be chosen from rosin, gum elemi, ester gum, hydrogenated castor oil, paraffin wax, microcrystalline wax, ozokerite, carnauba, ceresin or montana wax, beeswax, or polyisobutylene of molecular weight less than 60,000. Dispersing agents such as "Lubrol" (Registered Trade Mark) or an aluminium soap may be added together with dyes and pigments. The compositions may be used to coat paper, cardboard and woven fabrics and the inside of chemical containers; in bonding such materials to give moisture-proof products; and for making chemically resistant pipes and tubes. Specifications 514,687, 569,043 and 579,769 are referred to.

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