Patent ID: 8142682

Claim:
Process for making a multilayer of cholesteric liquid crystal polymer (CLCP), comprising at least two layers of CLCP, differing in at least one optical property, arranged on top of each other, said process comprising: a) depositing at least one coating layer of CLCP monomer precursor material, comprising cross-linkable groups, onto a flexible carrier substrate; b) orienting the at least one CLCP coating layer; c) partially curing the oriented layer of a), so as to leave an amount of cross-linkable groups in the layer for chemical inter-layer cross-linking with an adjacent coating layer through the polymer network; d) depositing a last coating layer of CLCP monomer precursor material, comprising cross-linkable groups, on top of a previous partially cured coating of the at least one CLCP coating layer; e) orienting the last CLCP coating layer; f) thoroughly curing the whole assembly, so as to essentially cross-link all of the cross-linkable groups throughout each coating layer and to form a mechanically unique solid body which is capable of being comminuted to pigment without delamination and which has an abrupt change of cholesteric liquid crystal pitch at an interface between layers of cholesteric liquid crystal polymer so that a change of cholesteric liquid crystal pitch from one layer to another is less than one pitch height without an intermediate pitch.