Patent ID: 8840807

Claim:
A compound represented by formula (1): wherein, R 1 is hydrogen or alkyl having 1 to 20 carbons, and in the alkyl, arbitrary —CH 2 — may be replaced by —O—, —CH═CH— or —C≡C—; R 2 and R 3 are independently hydrogen or methyl; A 1 is a single bond, 1,4-phenylene or 1,4-cyclohexylene; A 2 is independently 1,4-phenylene or 1,4-cyclohexylene; and in 1,4-phenylene and 1,4-cyclohexylene in A 1 and A 2 , arbitrary hydrogen may be replaced by halogen; Z 1 is a single bond or alkylene having 1 to 3 carbons; Z 2 is independently —O—, —COO—, —OCO— or alkylene having 1 to 6 carbons; Z 3 is independently a single bond or —O—; Z 4 is independently a single bond or alkylene having 2 to 20 carbons, and in the alkylene, arbitrary —CH 2 — may be replaced by —O—; X 1 is independently hydrogen, halogen, alkyl having 1 to 3 carbons or fluoroalkyl having 1 to 3 carbons; and a is independently 0 or 1, however, when a is 0, R 2 , R 3 and X 1 are hydrogen, and A 1 , Z 1 , Z 3 and Z 4 are a single bond, R 1 is alkyl having 4 to 20 carbons, and arbitrary —CH 2 — in the alkyl may be replaced by —O—, —CH═CH—, or —C≡C—; when a is 0, R 2 is hydrogen, X 1 is hydrogen or methyl, R 3 is methyl, and A 1 , Z 1 , Z 3 and Z 4 are a single bond, R 1 is alkyl having 1 to 20 carbons, and in the alkyl, arbitrary —CH 2 — may be replaced by —O—, —CH═CH— or —C≡C—; when a is 0, R 2 and R 3 are hydrogen, X 1 is methyl, and A 1 , Z 1 , Z 3 and Z 4 are a single bond, R 1 is alkyl having 2 to 20 carbons, and in the alkyl, arbitrary —CH 2 — may be replaced by —O—, —CH═CH— or —C≡C—; when a is 0, X 1 is methyl, R 2 and R 3 are hydrogen, and A 1 and Z 1 are a single bond, R 1 is a single bond or alkyl having 1 to 4 carbons, and Z 3 is —O—, Z 4 is alkylene having 3 to 20 carbons; and when a is 0, X 1 , R 1 , R 2 and R 3 are hydrogen, A 1 and Z 1 are a single bond, and Z 3 is —O—, Z 4 is alkylene having 3 to 20 carbons.