Patent ID: 8128778

Claim:
A method for the preparation of a bilayered material comprising a plurality of unidirectional monolayers consisting essentially of ultrahigh-molecular-weight polyethylene and essentially devoid of bonding matrices, with the direction of each monolayer being rotated with respect to the direction in an adjacent unidirectional monolayer, the method comprising: (a) providing a first unidirectional ultrahigh-molecular-weight polyethylene monolayer; (b) providing a plurality of unidirectional ultrahigh-molecular-weight polyethylene flat film strips; (c) aligning the plurality of unidirectional ultrahigh-molecular-weight-polyethylene flat film strips such that each strip is oriented in parallel to adjacent strips such that each strip overlaps with an adjacent strip only along an edge region thereof, said plurality of strips being laid over the first unidirectional ultrahigh-molecular-weight polyethylene monolayer, with the direction of said plurality of strips being rotated with respect to the direction of said first unidirectional ultrahigh-molecular-weight-polyethylene monolayer at an angle; and (d) compressing said plurality of unidirectional ultrahigh-molecular-weight-polyethylene flat film strips laid over said unidirectional ultrahigh molecular-weight polyethylene monolayer, thereby obtaining a bilayered material consisting essentially of ultrahigh-molecular-weight-polyethylene and essentially devoid of bonding matrices, comprising two compressed unidirectional monolayers with the direction of each monolayer being rotated at an angle with respect to the direction in an adjacent unidirectional monolayer.