Patent ID: 6495231
Filing Date: 2002-12-17
Classification: B32B,B41M,B42D,C08J,Y10S,Y10T

Abstract:
A curl-resistant, cross-sectionally symmetrical, laminated multilayer film substrate for use in the production of banknotes and security papers comprising:(a) an imbalanced biaxially oriented first layer having inner and outer sides, comprising at least about 50 weight percent of a high density polyethylene having a density of at least about 0.94, said first layer being oriented in at least a first direction to a degree which is at least three times less than the degree of orientation present in a second direction substantially normal to the first direction and wherein (a) further comprises a coextruded propylene copolymer skin on its inner side; (b) a balanced biaxially oriented second layer having inner and outer sides, comprising at least about 90 wt % polypropylene, said second layer being oriented in at least a first direction at an orientation ratio of at least 4:1 and oriented in a second direction substantially normal to said first direction at an orientation ratio of at least 6:1; (c) an imbalanced biaxially oriented third layer having inner and outer sides, comprising at least about 50 weight percent of a high density polyethylene having a density of at least about 0.94, said third layer being oriented in at least a first direction to a degree which is at least three times less than the degree of orientation present in a second direction substantially normal to the first direction; and (d) a laminating adhesive resin disposed between the inner sides of (a) and (c), said second layer being laminated to said first and third layers so that the first direction of orientation of said third layer is substantially aligned with the first direction of orientation of said first layer and wherein the outer sides of both (a) and (c) further comprise at least one (1) epoxy layer and at least one (1) antistatic layer, wherein the at least one (1) epoxy layer and at least one (1) antistatic layer may be the same layer or different layers.