Patent ID: 6773626
Filing Date: 2004-08-10
Classification: C09K,G02F,G06K

Abstract:
A reversible information display medium of liquid crystal type comprising a recording layer comprising a liquid crystalline composition, whose main component exhibits a glass state at room temperature, and a dichroic dye, said liquid crystalline composition being a high-molecular polymer liquid crystal or a mixture of a high-molecular polymer liquid crystal and a low-molecular liquid crystal, the high molecular polymer liquid crystal having an average molecular weight in the range of 5,000 to 100,000 the contents of said low-molecular liquid crystal in said liquid crystal composition being 30% by weight or below of said high-molecular polymer liquid crystal, said liquid crystalline composition exhibiting an isotropic liquid state or a liquid crystal domain state by the application of heat and further exhibiting a homeotropic orientation state by the application of both heat and electric field,said high-molecular polymer liquid crystal having a backbone chain obtained by addition polymerization of unsaturated compounds, and a side chain represented by the following general formula (1): whereinrings A, B, C and D independently represent an aromatic or aliphatic hydrocarbon 6 membered ring, or a heterocyclic or fused ring; Z, Z1, Z2 and Z3 independently represent a single bond, â€”CH2O, â€”OCH2â€”, â€”COOâ€”, â€”OCOâ€”, â€”CH2â€”, â€”CH2CH2â€”,â€”CH&boxH;CHâ€”,â€”CF&boxH;CFâ€” or â€”Câ‰¡Câ€”; R1 represents a hydrogen atom, a C1-8 straight or branched chain alkyl, alkoxy, alkoxyalkyl or fluoroalkyl group, a cyano group, a halogen atom, a carboxyl group or a hydroxyl group; X1 and X2 each independently represents a hydrogen atom, a halogen atom or a cyano group; l is 1 to 20; m is 0 or 1; n, p, q and r are independently 0 to 2; and n+p+q+r&gE;1, and said low-molecular liquid crystal being represented by the following general formula (2): whereinY1 represents a hydrogen atom or a C1-8 straight or branched chain alkyl, alkoxy, alkenyl, alkenyloxy, alkoxyalkyl, alkanoyloxy or alkoxycarbonyl group; rings E and F independently represent a benzene, cyclohexane, cyclohexene, pyrimidine or dioxane ring; W1 and W2 independently represent a single bond, â€”CH2Oâ€”, â€”OCH2Oâ€”, â€”COOâ€”, â€”OCOâ€”, â€”CH2â€”, â€”CH2CH2â€”, â€”CH&boxH;CHâ€” or â€”Câ‰¡Câ€”; Y represents a hydrogen or halogen atom; Y2 represents a cyano group, a halogen atom, a C1-8 straight or branch chained alkyl, alkoxy, alkenyl, alkenyloxy, alkoxyalkyl or alkanoyloxy group or a cyano group; Y3 represents a hydrogen atom, a halogen atom or a cyano group; and m is 0 to 2.