Abstract: Polyolefinic films having improved impermeability characteristics to gases and vapors, said films being coated on either one or both its surfaces by a layer of a copolymer containing functional hydroxylic groups, functional acid carboxylic groups and optionally--esteric groups and obtained by hydrolysis of copolymers consisting of an unsaturated ester and of an unsaturated acid or corresponding anhydride.

Abstract: There are disclosed coupled packaging sheets which are impermeable to gases and vapors and consist of two polyolefinic films coupled together, at least one being an oriented polypropylene film and at least one of the two films being coated with a lacquer which acts as a barrier to gases and vapors, and which is metallized on the face in contact with the other film.The present invention provides coupled sheets or films based on films of olefinic polymers, showing improved characteristics of impermeability to gases and vapors and which are particularly suited for the manufacture of containers, envelopes, bags, vessels and, in general, manufactured articles intended prevailingly for the packaging industry.

Abstract: Films comprising alpha-olefin polymers, such as polypropylene consisting essentially of recurring propylene units and having a substantial crystalline polypropylene content, and in particular isotactic polypropylene, are rendered poorly adhesive to the welding bars of automatic and semi-automatic machines conventionally used for the manufacture of containers, envelopes, bags, vessels and, in general, other manufactured articles useful in the packaging industry, by coating the films by a mixture of a copolymer of a vinyl ester with an unsaturated acid, a terpolymer of an alkyl acrylate, an alkyl-methacrylate and an unsaturated acid and a cross-linking amine.

Abstract: A bonded sheet for packaging is disclosed having a thickness of from 20 to 200 microns and comprising two films, one of which is obtained from chlorovinyl polymers and the other from olefinic polymers, and characterized in that one of the two films has, on its surface in contact with the other film, a metalized coating with a resistivity of from 1 to 5 Ohms. The chlorovinyl polymer film is a film, optionally stretched, prepared from polymers or copolymers of vinyl chloride, having a Fikentscher value K of from 40 to 80. The polyolefinic film is a film, optionally oriented by stretching, prepared from a polymer selected from the class consisting of a polyethylene with a melt index of from 0.5 to 15, a polypropylene with a melt index of from 1 to 20, a crystalline propylene/ethylene copolymer containing from 0.1 to 15% by weight of ethylene and with a melt index of from 1 to 20, or mixtures thereof.

Abstract: Films consisting essentially of alpha-olefin polymers, such as normally solid polypropylene consisting essentially of recurring propylene units and having a substantial crystalline polypropylene content, and in particular isotactic polypropylene, are coated with a ketonic resin resulting from the polycondensation of aldehydes with ketones, which coating renders the films readily thermoweldable and/or impervious to gases, vapors and the like. The coated films are useful for the manufacture of containers, covers, small bags, vessels and in general for the manufacture of articles useful in the packaging industry.

Abstract: There are disclosed polyolefinic films carrying two coatings, the first coating consisting of amino compounds and the second of a mixture of vinyl or vinylidene polymers or copolymers, epoxy resins and microcrystalline waxes, and which films, by virtue of the coatings, are readily thermoweldable, impervious to gases and vapors, and have improved resistance to sticking to the bars of conventional automatic and semi-automatic welding machines. A process for preparing the new polyolefinic films is also disclosed.

Abstract: Films comprising alpha-olefin polymers, such as normally solid polypropylene consisting essentially of recurring propylene units and having a substantial crystalline polypropylene content, and in particular isotactic polypropylene, are rendered easily thermoweldable and/or impervious to gases and vapors, and also given improved resistance to sticking against the welding bars of automatic and semi-automatic machines conventionally used for the manufacture of containers, envelops, bags, vessels and, in general, other manufactured articles useful in the packaging industry, by coating the films with a first layer comprising a polyalkyleneimine and a second layer comprising a mixture of an epoxy resin, an acrylic or methacrylic polymer or copolymer, and nitrocellulose.

Abstract: There is disclosed a bonded sheet for packaging, having a thickness ranging from 20 to 200 microns, a low transmittance, a low permeability to gases and vapors, a high resistance to perforation, and high anti-static characteristics, said bonded sheet consisting essentially of two films prepared from substantially crystalline polyolefin polymers or mixtures thereof and, optionally, from an interposed adhesive layer, wherein at least one of the two films is a film oriented by the stretching of polypropylene essentially constituted by isotactic macromolecules and having a melt index between 0.5 and 5, and wherein at least one of the two films is coated, on the surface thereof which is in contact with the other film, with a metallized layer (preferably aluminum) having a resistivity between 1 and 5 Ohms. One of the two films may be a film, optionally oriented by stretching, prepared from a polymer selected from the class consisting of a polyethylene having a melt index of from 0.