Abstract: Apparatus for the corona discharge treatment of a travelling web such as a plastics or cellulose film comprises a pair of spaced conductors with an associated alternating voltage power supply set at such a distance apart that the possibility of spark or arc discharge is avoided, at least one conductor having mounted thereto an electrode member extending towards the other conductor to define a gap across which a corona discharge can be formed. The electrode member consists of a dielectric material having a dielectric constant of at least 8, preferably at least 80, and may consist of a plate with an edge directed towards the other conductor. Preferably the plate is formed of one or more ceramic tiles based upon a titanium and/or zirconium compound. In another form the electrode member consists of a row of rods or two or more rows of spaced rods in staggered relationship.

Abstract: A heat-sealable oriented polypropylene film comprising a base oriented polypropylene film having on one surface a layer of a random propylene/ethylene copolymer (ethylene content 2-6% by weight) and on the other surface a predominantly linear random copolymer of ethylene and a further alpha olefin having at least three carbon atoms per molecule (for example propylene and butene-1) the further alpha olefin content being 6-40% by weight. The film is particularly useful for packaging merchandise on horizontal form-fill-seal packaging machines.

Abstract: An oriented heat-sealable antistatic polypropylene film is manufactured by applying to one or both surfaces of a base polypropylene film, preferably by co-extrusion, a layer of a heat-sealable olefinic polymer (for example, a predominantly linear random copolymer of ethylene with butene-1) containing between 0.2 and 10% by weight of an anionic hydrocarbyl (preferably long chain alkyl) sulphonate. A slip agent, for example oleamide, may also be incorporated in the base polypropylene film. The antistatic film has improved heat-sealing properties which permits it to be run successfully on packaging machinery at high speeds.

Abstract: A heat-sealable oriented plastic film comprising an oriented polypropylene film having on at least one surface a heat-sealable layer comprising a predominantly linear random copolymer of ethylene and up to 12 mole percent of at least one further alpha-olefin having at least three carbon atoms per molecule.

Abstract: A wrapping film for use in spin wrapping applications is produced by extruding a blend of polyethylene with between 0.5 and 10% by weight of polyisobutylene to form a film and treating one surface of the film with a corona discharge.

Abstract: A cohesive coating composition comprises in dispersion in a liquid a mixture of between 51 and 99% by weight of a natural or synthetic rubber and between 1 and 49% by weight of polyalkyl methacrylate in which dispersion there is incorporated between 5% and 35% by weight, based on the weight of the solids, of a inert particulate material having a mean particle size lying in the range between 0.2 and 50 microns.The compositions are applied to sheet materials used, for example, in packaging.

Abstract: A method for the manufacture of a copolymer coating composition comprises copolymerizing two or more copolymerizable monomers in dispersion in an aqueous medium in the presence of a surfactant to provide a dispersion of the copolymer containing between 30% and 70% by weight of solids then adding the copolymer dispersion with agitation to a sufficient amount of a volatile organic solvent for the copolymer to provide a water-in-solvent emulsion containing between 10% and 25% by weight of copolymer.Substrates coated with the copolymer coating compositions are also disclosed.

Abstract: A cohesive coating composition comprises in dispersion in a liquid a mixture of between 51 and 99% by weight of a natural or synthetic rubber and between 1 and 49% by weight of a polyalkyl methacrylate in which dispersion there is incorporated between 5% and 35% by weight, based on the weight of the solids, of an inert particulate material having a mean particle size lying in the range between 0.2 and 50 microns.The compositions are applied to sheet materials used, for example, in packaging.

Abstract: An oriented heat-sealable antistatic polypropylene film is manufactured by applying to one or both surfaces of a base polypropylene film, preferably by co-extrusion, a layer of a heat-sealable olefinic polymer (for example, a predominantly linear random copolymer of ethylene with butene-1) containing between 0.2 and 10% by weight of an anionic hydrocarbyl (preferably long chain alkyl) sulphonate. A slip agent, for example oleamide, may also be incorporated in the base polypropylene film. The antistatic film has improved heat-sealing properties which permits it to be run successfully on packaging machinery at high speeds.