A biaxially orientated multilayer film substrate comprising high density polyethylene for use in the production of banknotes and security documents

摘要

A laminate multi-layer film substrate for use in the production of banknotes. The multi-layer film consists of a first and second layer, being the same or different, each comprising at least 50 % by weight of a high density (at least .94 g/cc) polyethylene. The layers are biaxially orientated with respect to each other with the orientation of one layer being at least three times greater than the degree of orientation present in the other layer. The second layer is laminated to the first layer by thermal lamination, so that the first direction of orientation of the second layer is substantially aligned with the first direction of orientation of the first layer. The multi-layer film substrate comprises propylene copolymer skins on both the inner and outer sides, the skins comprising from 10-20 % by weight low density polyethylene, as well as an optically variable device which comprises a reflecting diffraction grating with a metallized thermoplastic film embossed with a diffraction pattern.