Optically anisotropic layer, optical film, polarizing plate, and image display device

Abstract

The present invention provides an optically anisotropic layer capable of producing an image display device that suppresses light leakage from oblique sides, as well as an optical film, polarizing plate, and image display device having the optically anisotropic layer. The optically anisotropic layer of the present invention is formed by curing a polymerizable liquid crystal composition containing a predetermined rod-shaped liquid crystal compound and a monofunctional compound, thereby fixing the alignment of the rod-shaped liquid crystal compound. In the optically anisotropic layer, the atomic number a1 of the rod-shaped liquid crystal compound and the atomic number a2 of the monofunctional compound satisfy the relationship of the following formula (1), and the rod-shaped liquid crystal compound is fixed in a state of being aligned perpendicular to the main surface of the optically anisotropic layer: Formula (1): 0.2 < a2 / a1 ≤ 0.68.

Claims

1. An optically anisotropic layer, which is formed by curing a polymerizable liquid crystal composition containing a rod-shaped liquid crystal compound and a monofunctional compound and fixing the alignment state of the rod-shaped liquid crystal compound, wherein: The rod-shaped liquid crystal compound is a compound represented by the following formula (I), P 1 -Sp 1 -(X 1 -Ar 1 ) n1 -(X 2 -Cy 1 ) m1 -(X 3 -Ar 3 ) k1 -X 4 -(Cy 2 -X 5 ) m2 -(Ar 2 -X 6 ) n2 -Sp 2 -P 2 (I) Wherein, in the formula (I), P 1 and P 2 each independently represents an acryloyloxy group or a methacryloyloxy group, Sp 1 and Sp 2 Each independently represents a single bond, a linear alkylene group having 1 to 14 carbon atoms or a branched alkylene group having 3 to 14 carbon atoms, or a divalent linking group in which one or more -CH2- constituting a linear alkylene group having 1 to 14 carbon atoms or a branched alkylene group having 3 to 14 carbon atoms is substituted with -O-, -S-, -NH-, -N(Q)- or -CO-, and Q represents a substituent. n1, m1, m2 and n2 each independently represent an integer from 0 to 2, wherein at least one of m1 and n1 represents 1 or 2, and at least one of m2 and n2 represents 1 or 2, k1 means 1 or 2, X 1 、X 2 、X 3 、X 4 、X 5 and X 6 Each independently represents a single bond or -CO-, -O-, -S-, -C(=S)-, -CR 1 R 2 -、-CR 3 =CR 4 -、-NR 5 - or a divalent linking group formed by a combination of two or more of them, R 1 ~R 5 Each independently represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 12 carbon atoms, wherein when n1 is 2, a plurality of X 1 They can be the same or different. When m1 is 2, multiple X 2 They can be the same or different. When k1 is 2, multiple X 3 They can be the same or different. When m2 is 2, multiple X 5 They can be the same or different. When n2 is 2, multiple X 6 They can be the same or different. Ar 1 and Ar 2 Each independently represents an aromatic ring which may have a substituent, wherein when n1 is 2, a plurality of Ar 1 They can be the same or different. When n2 is 2, multiple Ar 2 They can be the same or different. Cy 1 and Cy 2 Each independently represents an alicyclic ring which may have a substituent, wherein when m1 is 2, a plurality of Cy 1 They can be the same or different. When m2 is 2, multiple Cy 2 They can be the same or different. Ar 3 represents any aromatic ring selected from the group consisting of groups represented by the following formulae (Ar-1) to (Ar-7), wherein when k1 is 2, a plurality of Ar 3 They can be the same or different. Among them, in the formulas (Ar-1) to (Ar-7), * indicates the bonding position, Q 1 Indicates N or CH, Q 2 Indicates -S-, -O- or -N(R 6 )-,R 6 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, Y 1 represents an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent, an aromatic heterocyclic group having 3 to 12 carbon atoms which may have a substituent, or an alicyclic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent, wherein one or more -CH2- groups constituting the alicyclic hydrocarbon group may be substituted by -O-, -S- or -NH-, Z 1 , Z 2 and Z 3 each independently represents a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a monovalent aromatic heterocyclic group having 3 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -OR 7 、-NR 8 R 9 、-SR 10 、COOR 11 or-COR 12 , R 7 ~R 12 Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Z 1 and Z 2 can bond to each other to form aromatic rings, A 3 and A 4 Each independently represents a group consisting of -O-, -N(R 13 )-, -S- and -CO-, R 13 represents a hydrogen atom or a substituent, X represents a hydrogen atom or a non-metal atom of Groups 14 to 16 to which a substituent may be bonded, X 11 and X 12 Each independently represents a single bond or -CO-, -O-, -S-, -C(=S)-, -CR 1 R 2 -、-CR 3 =CR 4 -、-NR 5 - or a divalent linking group formed by a combination of two or more of them, R 1 ~R 5 Each independently represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 12 carbon atoms, Sp 4 and Sp 5 Each independently represents a single bond, a linear alkylene group having 1 to 14 carbon atoms or a branched alkylene group having 3 to 14 carbon atoms, or a divalent linking group in which one or more -CH2- constituting a linear alkylene group having 1 to 14 carbon atoms or a branched alkylene group having 3 to 14 carbon atoms is substituted with -O-, -S-, -NH-, -N(Q)- or -CO-, and Q represents a substituent. P 4 and P 5 Each independently represents a monovalent organic group, P 4 and P 5 At least one of represents a polymerizable group, Ax represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocycles, Ay represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms which has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring, The aromatic rings in Ax and Ay may have a substituent, and Ax and Ay may be bonded to form a ring. Q 3 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent, The monofunctional compound is a compound represented by the following formula (II), P 3 -Sp 3 -(X 7 -B 3 ) n3 -X 8 -B 2 (II) Wherein, in the formula (II), P 3 represents a polymerizable group that can polymerize with the rod-like liquid crystal compound, Sp 3 represents a single bond, a linear alkylene group having 1 to 14 carbon atoms or a branched alkylene group having 3 to 14 carbon atoms, or a divalent linking group in which one or more -CH2- constituting a linear alkylene group having 1 to 14 carbon atoms or a branched alkylene group having 3 to 14 carbon atoms is substituted with -O-, -S-, -NH-, -N(Q)-, or -CO-, wherein Q represents a substituent, n3 means 1 or 2, X 7 and X 8 Each independently represents a single bond or -CO-, -O-, -S-, -C(=S)-, -CR 1 R 2 -、-CR 3 =CR 4 -、-NR 5 - or a divalent linking group formed by a combination of two or more of them, R 1 ~R 5 Each independently represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 12 carbon atoms, wherein when n3 is 2, a plurality of X 7 They can be the same or different. B 3 represents an aromatic ring which may have a substituent or an aliphatic ring which may have a substituent, and B 3 At least one of the cyclohexane rings represents a cyclohexane ring, wherein, when n3 is 2, multiple B 3 They can be the same or different. B 2 represents a benzene ring having no substituent, The number of atoms a1 of the rod-shaped liquid crystal compound and the number of atoms a2 of the monofunctional compound satisfy the relationship of the following formula (1): The rod-like liquid crystal compound is fixed in a state of being aligned perpendicularly to the main surface of the optically anisotropic layer, Formula (1): 0.35<a2 / a1≤0.55 The number of atoms a1 of the rod-shaped liquid crystal compound represents the number of atoms on the bond connecting one end and the other end of the rod-shaped liquid crystal compound at the shortest distance, excluding the number of hydrogen atoms. The number of atoms a2 of the monofunctional compound represents the number of atoms on the bond connecting one end and the other end of the monofunctional compound at the shortest distance, excluding the number of hydrogen atoms. Here, one end and the other end of a compound refer to atoms that serve as the starting point and the ending point, respectively, when calculating the maximum number of atoms when atoms on bonds connecting the compound are connected at the shortest distance.

2. The optically anisotropic layer according to claim 1, wherein The rod-like liquid crystal compound is a compound that exhibits a smectic liquid crystal state.

3. The optically anisotropic layer according to claim 1, wherein In the formula (I), n1, m1, k1, m2 and n2 are all 1.

4. The optically anisotropic layer according to claim 1, wherein In the formula (I), n1 and n2 are both 0, m1 and m2 are both 2, and k1 is 1.

5. The optically anisotropic layer according to claim 1 or 2, wherein The rod-shaped liquid crystal compound has at least one 1,4-cyclohexylene group.

6. The optically anisotropic layer according to claim 1 or 2, wherein The monofunctional compound has at least one 1,4-cyclohexylene group or 1,4-phenylene group.

7. The optically anisotropic layer according to claim 1 or 2, wherein The content of the monofunctional compound is 1 to 100 parts by mass based on 100 parts by mass of the rod-like liquid crystal compound. The optically anisotropic layer according to claim 1 or 2, which is a positive C plate. 9 . An optical film comprising the optically anisotropic layer according to claim 1 . 10 . A polarizing plate comprising the optical film according to claim 9 and a polarizer. 11 . An image display device comprising the optical film according to claim 9 or the polarizing plate according to claim 10 . 12 . The image display device according to claim 11 , which is a liquid crystal display device. 13 . The image display device according to claim 11 , which is an organic EL display device.

Images