Liquid crystal compound, liquid crystal composition, composite material with encapsulated liquid crystal, and liquid crystal display device using same

1. A compound, represented by formula (1):

MG 1 -Z a -Sp-Z b -MG 2   (1)

wherein, in formula (1), MG 1 and MG 2 are each independently a mesogenic group;

Z a and Z b are independently a single bond or alkylene having 1 to 4 carbons, and in the Z a and the Z b , at least one piece of —CH 2 — may be replaced by —O—, —S—, —CO— or —SiH 2 —, at least one piece of —(CH 2 ) 2 — may be replaced by —CH═CH— or —C≡C—, and at least one piece of hydrogen may be replaced by fluorine;

Sp has an achiral structure represented by formula (sp-1):

-α-X-α-  (sp-1)

wherein, in formula (sp-1), α is each independently straight-chain alkylene having 1 to 20 carbons, and in the α, at least one piece of —CH 2 — may be replaced by —O—, —S—, —CO— or —SiH 2 —, at least one piece of —(CH 2 ) 2 — may be replaced by —CH═CH— or —C≡C—, and at least one piece of hydrogen may be replaced by fluorine;

X is represented by formula (I), formula (II) or formula (III):

wherein, in formula (I), Ra is a hydroxyl group or alkyl having 1 to 10 carbons, and in the Ra, at least one piece of —CH 2 — may be replaced by —O—, —S—, —CO— or —SiH 2 —, at least one piece of —(CH 2 ) 2 — may be replaced by —CH═CH— or —C≡C—, and at least one piece of hydrogen may be replaced by fluorine;

in formula (II), Rb and Rc are each independently fluorine, chlorine or alkyl having 1 to 10 carbons, and in the Rb and the Rc, at least one piece of —CH 2 — may be replaced by —O—, —S—, —CO— or —SiH 2 —, at least one piece of —(CH 2 ) 2 — may be replace by —CH═CH— or —C≡C—, and at least one piece of hydrogen may be replaced by fluorine; and

in formula (III), Q is an oxygen atom, a sulfur atom or alkylidene having 1 to 10 carbons, and in the Q, at least one piece of —CH 2 — may be replaced by —O—, —S—, —CO— or —SiH 2 —, at least one piece of —(CH 2 ) 2 — may be replaced by —CH═CH— or —C≡C—, and at least one piece of hydrogen may be replaced by fluorine.

2. The compound according to claim 1 , wherein, in formula (1), MG 1 and MG 2 are represented by formula (IV):

A 1 -Z 1 m A 2 -Z 2 n A 3 -Z 3 q A 4 -Z 4 r -Rd  (IV)

wherein, in formula (IV), Rd is independently —CN, —NCS, —C≡C—CN, —SF 5 , fluorine, chlorine or straight-chain alkyl having 1 to 20 carbons, and in the Rd, at least one piece of —CH 2 — may be replaced by —O—, —S—, —CO— or —SiH 2 —, and at least one piece of —(CH 2 ) 2 — may be replaced by —CH═CH— or —C≡C—; A 1 , A 2 , A 3 and A 4 are independently 1,4-cyclohexylene, 1,4-phenylene, cyclohexene-1,4-diyl, naphthalene-2,6-diyl, and in the rings, one piece of —CH 2 — may be replaced by —O—, —S—, —CO— or —SiH 2 —, and at least one piece of —(CH 2 ) 2 — may be replaced by —CH═CH— or —CH═N—, and in the rings, at least one piece of hydrogen may be replaced by fluorine, chlorine, —CF 3 , —CHF 2 , —CH 2 F, —OCF 3 , —OCHF 2 or —OCH 2 F;

Z 1 , Z 2 , Z 3 and Z 4 are independently a single bond or alkylene having 1 to 4 carbons, and in the Z 1 , the Z 2 , the Z 3 and the Z 4 , at least one piece of —CH 2 — may be replaced by —O—, —S—, —CO— or —SiH 2 —, at least one piece of —(CH 2 ) 2 — may be replaced by —CH═CH— or —C≡C—, and at least one piece of hydrogen may be replaced by fluorine; and

m, n, q and r are independently 0 or 1, and a sum of m, n, q and r is 2, 3 or 4.

3. The compound according to claim 2 , wherein, in formula (IV), Rd is fluorine, chlorine or straight-chain alkyl having 1 to 10 carbons, straight-chain alkenyl having 2 to 10 carbons, straight-chain alkoxy having 1 to 9 carbons, straight-chain alkoxyalkyl having 2 to 9 carbons, straight-chain alkenyloxy having 3 to 9 carbons, straight-chain polyfluoroalkyl having 1 to 10 carbons, straight-chain polyfluoroalkoxy having 1 to 9 carbons or straight-chain polyfluoroalkenyl having 2 to 10 carbons;

A 1 , A 2 , A 3 and A 4 are independently 1,4-cyclohexylene, 1,4-phenylene, cyclohexene-1,4-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl or naphthalene-2,6-diyl, and in the rings, at least one piece of hydrogen may be replaced by fluorine, chlorine, —CF 3 or —CHF 2 ; and

Z 1 , Z 2 and Z 4 are independently a single bond, —(CH 2 ) 2 —, —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH—CH—, —CF—CF—, —C≡C—, —CH 2 CO—, —COCH 2 —, —CH 2 SiH 2 —, —SiH 2 CH 2 —, —(CH 2 ) 2 COO—, —OCO(CH 2 ) 2 —, —(CH 2 ) 2 CF 2 O—, —OCF 2 (CH 2 ) 2 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 — or —(CH 2 ) 4 —.

4. The compound according to claim 1 , wherein, in formula (1), Z a and Z b are independently a single bond, —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CF═CF—, —CH 2 CO—, —C≡C—, —COCH 2 —, —CH 2 SiH 2 — or —SiH 2 CH 2 —;

in formula (sp-1), α is straight-chain alkylene having 1 to 10 carbons, and in the α, at least one piece of —(CH 2 ) 2 — may be replaced by —CH═CH— or —C≡C—, and at least one piece of hydrogen may be replaced by fluorine;

in formula (I), Ra is a hydroxyl group, alkyl having 1 to 5 carbons, alkenyl having 2 to 5 carbons, alkoxy having 1 to 4 carbons, alkoxyalkyl having 2 to 4 carbons, alkenyloxy having 3 to 4 carbons, polyfluoroalkyl having 1 to 5 carbons, polyfluoroalkoxy having 1 to 4 carbons or polyfluoroalkenyl having 2 to 5 carbons;

in formula (II), Rb and Rc are each independently fluorine, alkyl having 1 to 5 carbons, alkenyl having 2 to 5 carbons, alkoxy having 1 to 4 carbons, alkoxyalkyl having 2 to 4 carbons, alkenyloxy having 3 to 4 carbons, polyfluoroalkyl having 1 to 5 carbons, polyfluoroalkoxy having 1 to 4 carbons or polyfluoroalkenyl having 2 to 5 carbons; and

in formula (III), Q is an oxygen atom or alkylidene having 1 to 5 carbons.

5. The compound according to claim 4 , wherein, in formula (1), Z a and Z b are independently a single bond, —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH═CH—, —CF═CF— or —C≡C—; and

in formula (sp-1), α is straight-chain alkylene having 1 to 10 carbons;

in formula (I), Ra is alkyl having 1 to 5 carbons, alkenyl having 2 to 5 carbons or polyfluoroalkyl having 1 to 5 carbons;

in formula (II), Rb and Rc are each independently fluorine, alkyl having 1 to 5 carbons, alkenyl having 2 to 5 carbons or polyfluoroalkyl having 1 to 5 carbons; and

in formula (III), Q is an oxygen atom or alkylidene having 1 to 3 carbons.

6. The compound according to claim 1 , wherein, in formula (1), MG 1 and MG 2 are represented by formula (IV-1):

wherein, Rd is independently —CN, —NCS, —C≡C—CN, —SF 5 , fluorine, chlorine, straight-chain alkyl having 1 to 6 carbons, straight-chain alkenyl having 2 to 6 carbons, straight-chain alkoxy having 1 to 5 carbons, straight-chain polyfluoroalkyl having 1 to 6 carbons, straight-chain polyfluoroalkoxy having 1 to 5 carbons or straight-chain polyfluoroalkenyl having 2 to 6 carbons;

A 11 and A 31 are 1,4-cyclohexylene or 1,4-phenylene;

Y 21 , Y 22 , Y 23 , Y 41 , Y 42 and Y 43 are independently hydrogen, fluorine, —CF 3 or —CF 2 H;

Z 11 , Z 21 , Z 31 and Z 41 are independently a single bond, —(CH 2 ) 2 —, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH═CH—, —CF═CF—, or —C≡C—; and

s, t, u and v are independently 0, 1 or 2, and a sum of s, t and u is 2, 3 or 4, in which t is 1 without exception, and when any one of s, t, u and v is 2, a plurality of ring structures may be an identical group or a different group, and a plurality of Z 11 , Z 21 , Z 31 and Z 41 may be an identical group or a different group.

7. The compound according to claim 1 , wherein, in formula (1), MG 1 and MG 2 are represented by formulas (IV-1-1-1) to (IV-1-1-55):

wherein, in formula (IV-1-1-1) to formula (IV-1-1-55), Rd is independently —CN, —NCS, —C≡C—CN, —SF 5 , fluorine, —CF 3 , —CF 2 H, —OCF 3 or —C 2 F 5 ; and Z 11 , Z 21 and Z 31 are independently a single bond, —(CH 2 ) 2 —, —CF 2 O—, —CH═CH—, —CF═CF— or —C≡C—, and a plurality of Z 11 , Z 21 or Z 31 may be an identical group or a different group.

8. The compound according to claim 1 , wherein, in formula (1), MG 1 and MG 2 are represented by formulas (IV-1-2-1) to (IV-1-2-30):

wherein, in formulas (IV-1-2-1) to (IV-1-2-30), Rd is independently straight-chain alkyl having 1 to 6 carbons, straight-chain alkenyl having 2 to 6 carbons or straight-chain alkoxy having 1 to 6 carbons; and Z 11 , Z 21 and Z 31 are independently a single bond, —(CH 2 ) 2 —, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH═CH—, —CF═CF— or —C≡C—, and a plurality of Z 11 , Z 21 and Z 31 may be an identical group or a different group.

9. A liquid crystal composition, containing the compound according to claim 1 .

10. The liquid crystal composition, containing at least two kinds of the compounds according to claim 1 .

11. The liquid crystal composition according to claim 10 , further containing a compound represented by formula (cp-1):

R 31 -MG 31 -Z 3a -Sp 3 -Z 3b -MG 32 -R 32   (cp-1)

wherein, R 31 and R 32 are each independently fluorine, chlorine, —CN, —NCS, —SF 5 or alkyl having 1 to 20 carbons, and in the R 31 and R 32 , at least one piece of —CH 2 — may be replaced by —O—, —S—, —CO— or —SiH 2 —, and at least one piece of —(CH 2 ) 2 — may be replaced by —CH═CH— or —C≡C—; MG 31 and MG 32 are each independently a mesogenic group; Z 3a and Z 3b are each independently —O—, —S—, —CO—, —COO—, —OCO—, —O—CO—O—, —CO—NH—, —NH—CO—, —CH 2 CH 2 —, —OCH 2 —, —CH 2 O—, —SCH 2 —, —CH 2 S—, —CH═CH—, —CH═CHCOO—, —OCO—CH═CH—, —C≡C— or a single bond; and Sp 3 is a straight-chain spacer group containing 4 to 40 carbons, and at least one piece of a —CH 2 group may be replaced by —O—, —S—, —NH—, —N(CH 3 )—, —OCO—, —S—CO—, —O—COO—, —CO—S—, —CO—O—, —CH═CH— or —C≡C—.

12. The liquid crystal composition according to claim 9 , further containing at least one selected from an optically active compound and a polymerizable compound.

13. The liquid crystal composition according to claim 9 , further containing at least one selected from an antioxidant and an ultraviolet light absorber.

14. Sheath-core conjugate fibers with an encapsulated liquid crystal, wherein the liquid crystal composition according to claim 9 is applied as a core component.

15. A fiber aggregate containing a liquid crystal, formed by uniaxially arranging the conjugate fibers with the encapsulated liquid crystal according to claim 14 .

16. A fiber composite containing a liquid crystal, composed of the fiber aggregate containing the liquid crystal according to claim 15 , and a binder.

17. A liquid crystal display device, including the liquid crystal composition according to claim 9 .

18. The liquid crystal display device according to claim 17 , wherein the device is a flexo-electric apparatus.

19. A liquid crystal display device, including the fiber composite containing the liquid crystal according to claim 16 .

20. The liquid crystal display device according to claim 19 , wherein the device is a flexo-electric apparatus.