Abstract: A method of heat sealing a heat sealable multilayer film having a first film surface which is heat sealable to itself or to other surfaces and a second film surface including particles of a cross-linked polymethyl methacrylate as an antiblock agent, the method comprising sliding the said second film surface over a heated heat sealing surface before effecting heat sealing of the film to itself or to another surface using said heated heat sealing surface.

Abstract: Biaxially oriented polyolefin films comprising a core layer of propylene polymer, an intermediate layer of a non-voided, substantially non-pigmented propylene polymer on the core layer, and an outer skin layer of a polyolefin including titanium dioxide as a pigment are disclosed. Such films have good gloss.

Abstract: Biaxially oriented polypropylene films having a core layer of voided polypropylene homopolymer with a layer of non-voided polypropylene homopolymer on one surface thereof and an outer, printable layer on the non-voided layer, the core layer and/or the said non-voided layer including titanium dioxide. Such films can be used to produce labels, for example with densities in the range 0.55 to 0.80 despite the presence of the titanium dioxide.

Abstract: This invention concerns biaxially oriented polypropylene films containing from 1 to 40 percent by weight of a hydrocarbon resin, the resin being substantially miscible with the polypropylene, and the film having a crease retention of at least 50% as measured by ASTM D920-49. The hydrocarbon resin is preferably a terpene resin, a hydrogenated synthetic resin or a compatible rosin. Crease retention values in excess of 70% have been achieved in particular by orienting the films at a temperature of at least 10 Centigrade degrees below the crystalline melting point of the polypropylene.

Abstract: This invention concerns biaxially oriented polypropylene films containing from 1 to 40 percent by weight of a hydrocarbon resin, the resin being substantially miscible with the polypropylene, and the film having a crease retention of at least 50% as measured by ASTM D920-49. The hydrocarbon resin is preferably a terpene resin, a hydrogenated synthetic resin or a compatible rosin. Crease retention values in excess of 70% have been achieved in particular by orienting the films at a temperature of at least 10 Centigrade degrees below the crystalline melting point of the polypropylene.