Photo-alignment copolymer, photo-alignment film, and optical laminate

1. A photo-alignment copolymer comprising:

a repeating unit A including a photo-alignment group represented by Formula (A); and

a repeating unit B including a crosslinkable group represented by Formula (B),

in Formula (A), R 1 represents a hydrogen atom or a methyl group, L 1 is a divalent linking group represented by any one of Formulae (1) to (10),

in Formulae (1) to (10), *1 represents the bonding position with the carbon atom constituting the main chain in Formula (A), and *2 represents the bonding position with the carbon atom constituting the carbonyl group in Formula (A), R 2 , R 3 , R 4 , R 5 , and R 6 each independently represent a hydrogen atom or a substituent, and among R 2 , R 3 , R 4 , R 5 , and R 6 , two adjacent groups may be bonded to form a ring, and

in Formula (B), R 7 represents a hydrogen atom or a methyl group, L 2 represents a divalent linking group, and X represents a crosslinkable group,

wherein X in Formula (B) is at least one crosslinkable group selected from the group consisting of Formulae (X1) to (X4),

in Formulae (X1) to (X4), * represents the bonding position with L 2 in Formula (B), R 8 represents any one of a hydrogen atom, a methyl group, or an ethyl group, and S in Formula (X4) represents any one of a vinyl group, an allyl group, a styryl group, an acryloyl group, and a methacryloyl group, and

wherein the photo-alignment copolymer has a weight-average molecular weight of 10.000 to 500 000.

2. The photo-alignment copolymer according to claim 1 ,

wherein the repeating unit B includes a repeating unit in which X in Formula (B) is a crosslinkable group represented by any one of Formula (X1), Formula (X2), or Formula (X3) and a repeating unit in which X in Formula (B) is a crosslinkable group represented by Formula (X4).

3. The photo-alignment copolymer according to claim 1 ,

wherein L 2 in Formula (B) is a divalent linking group formed by combining at least two selected from the group consisting of a linear, branched, or cyclic alkylene group having 1 to 18 carbon atoms and optionally having a substituent, an arylene group having 6 to 12 carbon atoms and optionally having a substituent, an ether group, a carbonyl group, and an imino group optionally having a substituent.

4. The photo-alignment copolymer according to claim 1 ,

wherein L 1 in Formula (A) is a divalent linking group represented by any one of Formula (2), Formula (3), Formula (7), or Formula (8).

5. The photo-alignment copolymer according to claim 1 ,

wherein at least R 4 among R 2 , R 3 , R 4 , R 5 and R 6 in Formula (A) represents a substituent.

6. The photo-alignment copolymer according to claim 5 ,

wherein R 2 , R 3 , R 5 , and R 6 in Formula (A) all represent a hydrogen atom.

7. The photo-alignment copolymer according to claim 5 ,

wherein R 4 in Formula (A) is an electron-donating substituent.

8. The photo-alignment copolymer according to claim 7 ,

wherein the electron-donating substituent is an alkoxy group having 6 to 16 carbon atoms.

9. The photo-alignment copolymer according to claim 1 ,

wherein the substituents represented by R 2 , R 3 , R 4 , R 5 , and R 6 in Formula (A) each independently represent a halogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a linear halogenated alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a cyano group, an amino group, or a group represented by Formula (11),

in Formula (11), * represents a bonding position with a benzene ring in Formula (A), and R 9 represents a monovalent organic group.

10. The photo-alignment copolymer according to claim 1 ,

wherein a content a of the repeating unit A and a content b of the repeating unit B satisfy Formula (12) by mass ratio,

0.03≤ a /( a+b )≤0.5 . . .  (12).

11. The photo-alignment copolymer according to claim 10 ,

wherein the content a of the repeating unit A and the content b of the repeating unit B satisfy Formula (13) by mass ratio,

0.03≤ a /( a+b )≤0.3 . . .  (13).

12. The photo-alignment copolymer according to claim 10 ,

wherein the content a of the repeating unit A and the content b of the repeating unit B satisfy Formula (14) by mass ratio,

0.03≤ a /( a+b )0.2 . . .  (14).

13. The photo-alignment copolymer according to claim 1 ,

wherein the weight-average molecular weight of the photo-alignment copolymer is 30,000 to 300,000.

14. A photo-alignment film which is formed from a photo-alignment film composition containing the photo-alignment copolymer according to claim 1 .

15. An optical laminate comprising:

the photo-alignment film according to claim 14 ; and

an optically anisotropic layer which is formed from a liquid crystal composition containing a liquid crystal compound.