Abstract: A multilayered film exhibiting good transparency, welding resistance, puncture resistance and impact strength having an outer layer selected from the group consisting of: (1) homopolymers of polypropylene, (2) ethylene/propylene copolymers and (3) blends of (a) high density polyethylene and (b) propylene and ethylene block copolymers; an inner layer of a different composition from the outer layer and selected from the group consisting of ethylene and &agr;-olefin copolymers, and ethylene and &agr;-olefin copolymers blended with low density polyethylene; and a complex intermediate layer joining the outer layer to the inner layer, the complex intermediate layer having a plurality of sublayers defining an upper nucleus B1, a core B2 and a lower nucleus B3, the upper nucleus being a propylene and ethylene copolymer and the lower nucleus being an ethylene copolymer with an ethylene content greater than the upper nucleus.

Abstract: The present invention is directed to modified polyolefin films with stable twist retention and dead fold properties to be employed in wrapping in general, and particularly in wrapping small items. The films produced by the present invention exhibit improved moisture vapor barrier and oxygen barrier properties. The inventive films are obtained by extrusion and stretching of a ternary mixture comprising (1) isotactic polypropylene; (2) high density polyethylene; and (3) a glassy amorphous low molecular weight resin. Multilayer films are also provided.

Abstract: Heat-sealable films are described which are constituted by a polyolefin film, particularly polypropylene, having on one surface thereof a layer of primer, applied in aqueous or aqueous-alcoholic solution, and chosen from: polyethylenimines, products of the condensation of urea or melamine with formaldehyde, particularly the etherified compounds; alkoxyalkyl melamine polyhydroxylates; or mixtures of the said compounds; and, on the other surface thereof, a layer of the said primer or one similar to the first, followed by a layer of vinyl, vinylidene or acrylic polymer or copolymer.

Abstract: Flexible double-layer polypropylene laminate consisting essentially of a biaxially oriented film of isotactic polypropylene with an atactic polypropylene content of less than 6% by weight and an intrinsic viscosity of from 1.5 to 3 dl/g, adhesively bonded to a non-oriented film of isotactic polypropylene with an atactic polypropylene content of from 15 to 30% by weight, said polypropylene in said non-oriented film deriving directly from the polymerization of propylene and having an intrinsic viscosity of from 2 to 8 dl/g.

Abstract: A flexible double-layer polypropylene laminate consisting of a bioriented film consisting essentially of isotactic polypropylene with an atactic polypropylene content of less than 6% by weight and an intrinsic viscosity (standard ASTM D 1601) of from 1.5 to 3.0 dl/g, adhesively bonded with a non-oriented film consisting essentially of a mixture of isotactic polypropylene and atactic polypropylene, the latter in an amount of from 15 to 30% by weight of the total weight of the said mixture, the isotactic polypropylene of said mixture having an intrinsic viscosity (standard ASTM D 1601) of from 1.0 to 1.5 dl/g and the atactic polypropylene of said mixture having a density (standard ASTM D 1505) of from 0.855 to 0.865 g/cm.sup.3 and a viscosity at 160.degree. C. of from 3,000 to 10,000 cps.

Abstract: A surface-activated polyolefin is coated by applying a solution in an organic solvent of a vinylidene copolymer material containing from 35 to 60 wt.% of vinylidene chloride, from 30 to 50 wt.% of alkyl ester of acrylic or methacrylic acid, from 1 to 10 wt.% of acrylic and/or methacrylic acids and from 1 to 10 wt.% of hydroxyalkyl ester of acrylic or methacrylic acid, a ratio of from 0.5:1 to 5:1 being maintained in the material between the number of carboxyl groups and the number of hydroxyl groups and said solution containing a latent catalyst for the cross-linking of said material, and heat-treating at 70.degree.-130.degree. C. said coated film to provoke said cross-linking.The coating shows an excellent adhesion to the film and improves the thermal weldability, impermeability and flexibility of the latter.