Wolff Walsrode Ag

Klaus Lund

Holger Preiss

Rainer Brandt

Holger Eggers

Bernd Sperlich

Richarda Bochow

The present invention relates to a heat sealable, unoriented multi-layer film consisting of a sequence of layers (I) comprising one or more plies on the outer side of the film, a sequence of layers (II) also comprising at least one ply, denoted the heat sealable layer, on the other outer side of the film, optionally together with a coupling sequence of layers (III), also of one or more plies, between the sequences of layers (I) and (II), wherein the multi-layer film is characterized in that the sequence of layers (I) contains at least one layer (i) of a linear alternating copolymer (1) of carbon monoxide and at least one ethylenically unsaturated olefin, optionally together with one or more layers (ii) containing polyamide, characterised in that the ratio between the thicknesses of the sequence of layers (I) and the total multi-layer film is no greater than 0.6 and no less than 0.15, that the total thickness of the multi-layer film is no less than 50 and no more than 300 &mgr;m, and that at least one melting point, determined using the DSC method to ASTM 3418, of one of the polymeric components present in the sequence of layers (II) is at least 50&deg; C. lower than at least one melting point, determined using the DSC method to ASTM 3418, of one of the polymers present in the sequence of layers (I).

Flexible, multi-layer film having elevated stiffness, dimensional stability and flex crack resistance

The invention relates to composite films having a particularly good barrier effect against gases and water vapor without a metal layer, for example of aluminum, having to be present.

Metal-free barrier-layer films

The composite film contains individual layers of polyvinyl alcohol, a polyolefin, an ethylene/vinyl alcohol and a polyolefin in that order and is comparable in its barrier properties to water vapor and gas with composite films containing metal layers without having any of their disadvantages.

Growing community of inventors

Walsrode, Germany

Klaus Lund