Hoechst Aktiengesellschaft

Gunther Crass

Siegfried Janocha

Lothar Bothe

Hartmut Hensel

Wolfgang Dietz

Peter Hammerschmidt

Dieter Gebhardt

Walter Siefried

A sealable, transparent polyolefinic multilayer film composed of a polypropylene base layer, a non-sealable surface layer, and a sealable surface layer, and process therefor. The sealable surface layer has a low minimum sealing temperature and is made from a copolymer of propylene and ethylene or butene-1 units and/or a terpolymer of ethylene, propylene and butene-1 units. The non-sealable layer is a combination of a propylene homopolymer, a slip agent, and an anti-blocking agent. The process includes coextruding the three layers, biaxially stretching the coextruded film, and subjecting the non-sealable layer to a corona-discharge treatment.

Sealable, transparent polyolefinic multilayer film

A sealable, opaque polyolefinic multilayer film composed of a polypropylene base layer, a non-sealable surface layer, and a sealable surface layer, and process therefor. The sealable surface layer has a low minimum sealing temperature and is made from a copolymer of propylene and ethylene or butene-1 units and/or a terpolymer of ethylene, propylene and butene-1 units. The non-sealable layer is a combination of a propylene homopolymer and a slip agent. The base layer contains an additive which is incompatible with polypropylene. The process includes stretching of the film, and during the stretching step, the polymer matrix is torn open around the additive particles to form vacuoles which give the base layer a degree of opacity.

Sealable, opaque polyolefinic multilayer film and process therefor

Disclosed is a sealable transparent multilayer film, comprising: a base layer comprised of a propylene polymer and at least one sealable layer comprised of a combination of:

Sealable multilayer film for packaging purposes

An adhesive tape is described, which is destroyed by delamination upon removal from a substrate but which may be unwound from a supply roll without destruction. The adhesive tape comprises an inner layer of a polyolefin having 2 to 6 carbon atoms containing in a finely distributed form solid organic particles with a size of from about 0.2 to 20 microns and polyolefin cover layers on both sides of the inner layer, one of which is coated with an adhesive and the other with a release coat.

Adhesive tape

Disclosed is a film for use in the field of electrical insulation comprising a biaxially stretched rough polypropylene film comprising a plurality of first zones of high roughness, the first zones having a relatively high number of .alpha.-crystallites; and a plurality of second zones of substantially lesser roughness, the second zones having a substantially lesser number of .alpha.-crystallites than the first zones, the first zones being adjacent to the second zones and the adjacent first and second zones forming fine channels between each other. Also disclosed is a method for producing this film.

Rough electrical insulating film of polypropylene and process for the

Disclosed is an opaque film of thermoplastic organic material which has been oriented by biaxial stretching, comprising a base layer of a polymer or copolymer of an .alpha.-olefin having 2 to 6 carbon atoms containing between about 1 and 25 percent by weight, calculated on the weight of the polymer, of finely distributed solid particles ranging in size from about 0.2 to 20 .mu.m, and carried on at least one surface of the base layer, a heat-sealable layer comprising a copolymer of propylene with ethylene, a copolymer of propylene with butene, or a terpolymer of propylene with ethylene and a further .alpha.-olefin having from 4 to 10 carbon atoms. Also disclosed are a method of making this film and a package made therefrom.

Heat-sealable plastic film, process for its manufacture, and the use of

Disclosed is a biaxially stretched, composite polypropylene film suitable for use as an electrical insulating film, comprising a first layer comprising a first propylene polymer and having a maximum roughness height R.sub.z of its exposed surface of about 0.5 .mu.m, and a second layer contiguous to the first layer comprising a second propylene polymer having a composition different from the first propylene polymer and having a roughness height R.sub.z on its exposed surface ranging between about 0.2 .mu.m and 0.4 .mu.m, with the composite film having a modulus of elasticity of at least about 2000 N/mm.sup.2 in all directions of the plane of the film and a DC dielectric strength of at least about 650 V/.mu.m. Also disclosed is a capacitor comprised of a plurality of these composite films having a metal surface layer and being laminated with one another.

Growing community of inventors

Taunusstein, Germany

Gunther Crass