US Patent 7985455 Polymerizable liquid crystal compound, liquid crystal composition, and polymer

The compound of the present invention is represented by the formula (1). In the formula (1), R1 and R2 are hydrogen, fluorine, chlorine, methyl or ethyl; X1 and X2 are hydrogen, fluorine, methyl or trifluoromethyl; Z1 and Z2 are a single bond, —COO—, —OCO—, —CH═CH—COO—, —OCO—CH═CH—, —CH2CH2—COO—, —OCO—CH2CH2—, —CH2O—, —CONH—, —(CH2)4—, —CH2CH2— or —C≡C—; Z3 and Z4 are a single bond or —O—; A1 and A2 are 1,4-cyclohexylene, 1,4-phenylene, 1,3-phenylene, pyridin-2,5-diyl, pyrimidin-2,5-diyl, naphthalen-2,6-diyl or tetrahydronaphtlane-2,6-diyl; and Y1 and Y2 are alkylene having from 2 to 20 carbon atoms.