Wolff Walsrode Ag

Agfa-Gavaert, A.g.

Richarda Bochow

Klaus Lund

Holger Preiss

Heiko Tamke

Helmut Bergmann

Karl Hammerschmidt

Siegfried Eikemeier

The invention relates to a multilayer composite film consisting of a surface layer A, a gas barrier layer C, a heat sealing layer D and, optionally, adhesive or coupling layers B, the individual layers being arranged as follows in the composite film: A a biaxially stretched, white opaque polypropylene film, B an adhesive or coupling layer, C a gas barrier layer with a permeability to oxygen of at most 30 Ncm.sup.3 /m.sup.2 d bar (23.degree. C./0% relative humidity), B an adhesive or coupling layer, D a heat sealing layer, layers A and C optionally being interchangeable.

White opaque barrier layer film with excellent lay-flat properties

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 tamperproof document consists of a photographic material as information carrier which is laminated on one or both sides with a transparent foil. The foil is attached to the surface of the information carrier by a layer of adhesive containing poly-1,2-alkyleneimine. The document is eminently saft against falsification.

Tamperproof document and a process for producing the same

Growing community of inventors

Fallingbostel, Germany

Richarda Bochow