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

An optically anisotropic layer in which a polymerizable liquid crystal composition is immobilized in a liquid crystal state of a smectic phase, the polymerizable liquid crystal composition including a polymerizable rod-shaped liquid crystal compound exhibiting a liquid crystal state of a smectic phase and an additive,

• wherein a molecular length A (Å) of the polymerizable rod-shaped liquid crystal compound, a layer interval B (Å) of the smectic phase of the optically anisotropic layer, and a molecular length C (Å) of the additive satisfy a relationship of Expression (1-1),
• 0.5×B≤C≤0.6×A (1-1),
• wherein the polymerizable rod-shaped liquid crystal compound is a compound represented by Formula (I) or any one of the following compounds (1-1) to (1-19),
• L1-SP1-D5-(A1)a1-D3-(G1)g1-D1-[Ar-D2]q1-(G2)q2-D4-(A2)a2-D6-SP2-L2 (I)
• in Formula (I),
• a1, a2, g1, and g2 each independently represent 0 or 1, provided that at least one of a1 or g1 represents 1, and at least one of a2 or g2 represents 1,
• q1 represents 1 or 2,
• D1, D2, D3, D4, D5, and D6 each independently represent a single bond;
• or —CO—, —O—, —S—, —C(═S)—, —CR1R2—, —CR3═CR4—, —NR5—, or a divalent linking group consisting of a combination of two or more of these groups, where R1 to R5 each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 12 carbon atoms, provided that in a case where q1 is 2, a plurality of D2's may be the same as or different from each other,
• G1 and G2 each independently represent an aromatic ring having 6 to 20 carbon atoms, which may have a substituent, or a divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms, which may have a substituent, and one or more of —CH2-'s contained in the alicyclic hydrocarbon group may be substituted with —O—, —S—, or —NH—,
• A1 and A2 each independently represent an aromatic ring having 6 to 20 carbon atoms, which may have a substituent, or a divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms, which may have a substituent, and one or more of —CH2-'s contained in the alicyclic hydrocarbon group may be substituted with —O—, —S—, or —NH—,
• SP1 and SP2 each independently represent a single bond, a linear alkylene group having 1 to 12 carbon atoms, a branched alkylene group having 3 to 12 carbon atoms, or a divalent linking group in which one or more of —CH2-'s contained in the linear or branched alkylene group are substituted with —O—, —S—, —NH—, —N(Q)-, or —CO—, where Q represents a substituent,
• L1 and L2 each independently represent a monovalent organic group, and at least one of L1 or L2 represents a polymerizable group, provided that in a case where Ar is an aromatic ring represented by Formula (Ar-3), at least one of L1 or L2, or L3 or L4 in Formula (Ar-3) represents a polymerizable group, and
• Ar represents any of aromatic rings selected from the group consisting of groups represented by Formulae (Ar-1) to (Ar-7), provided that in a case where q1 is 2, a plurality of Ar's may be the same as or different from each other,
• in Formulae (Ar-1) to (Ar-7),
• * represents a bonding position, in a case where q1 represents 1, one of two * represents a bonding position to D1, and the other represents a bonding position to D2;
• in a case where q1 represents 2 and Ar exists between D1 and D2, one of two * represents a bonding position to D1 and the other represents a bonding position to D2;
• in a case where q1 represents 2 and Ar exists between two D2, two * represent a bonding position to D2, respectively,
• Q1 represents N or CH,
• Q2 represents-S—, —O—, or —N(R6)—, where R6 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,
• Y1 represents an aromatic hydrocarbon ring 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, and one or more of —CH2-'s contained in the alicyclic hydrocarbon group may be substituted with —O—, —S—, or —NH—,
• Z1, Z2, and Z3 each independently represent 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 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, —OR7, —NR8R9, —SR10, —COOR11, or —COR12, R7 to R12 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Z1 and Z2 may be bonded to each other to form an aromatic ring,
• A3 and A4 each independently represent a group selected from the group consisting of —O—, —N(R13)—, —S—, and —CO—, where R13 represents a hydrogen atom or a substituent,
• X represents a non-metal atom of Groups XIV to XVI, to which a hydrogen atom or a substituent may be bonded,
• D7 and D8 each independently represent a single bond;
• or —CO—, —O—, —S—, —C(═S)—, —CR1R2—, —CR3═CR4—, —NR5—, or a divalent linking group consisting of a combination of two or more of these groups, where R1 to R5 each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 12 carbon atoms,
• SP3 and SP4 each independently represent a single bond, a linear alkylene group having 1 to 12 carbon atoms, a branched alkylene group having 3 to 12 carbon atoms, or a divalent linking group in which one or more of —CH2-'s contained in the linear or branched alkylene group are substituted with —O—, —S—, —NH—, —N(Q)-, or —CO—, where Q represents a substituent,
• L3 and L4 each independently represent a monovalent organic group, and at least one of L3 or L4 represents a polymerizable group,
• Ax represents 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,
• 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 ring in each of Ax and Ay may have a substituent, and Ax and Ay may be bonded to each other to form a ring, and
• Q3 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, which may have a substituent,
• wherein the additive is a compound represented by Formula (II),
• L5-SP5-D9-(A5)a3-D10-(G3)g3-D11-M (II),
• in Formula (II), a3 and g3 each independently represent an integer of 0 to 2, provided that a3 and g3 represent integers of 1 to 3 in total,
• D9, D10, and D11 each independently represent a single bond;
• or —CO—, —O—, —S—, —C(═S)—, —CR1R2—, —CR3═CR4—, —NR5—, or a divalent linking group consisting of a combination of two or more of these groups, where R1 to R5 each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 12 carbon atoms,
• G3 represents an aromatic ring having 6 to 20 carbon atoms, which may have a substituent, or a divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms, which may have a substituent, and one or more of —CH2-'s contained in the alicyclic hydrocarbon group may be substituted with —O—, —S—, or —NH—, it should be noted that in a case where g3 is 2, a plurality of G3's may be the same as or different from each other,
• A5 represents an aromatic ring having 6 to 20 carbon atoms, which may have a substituent, or a divalent alicyclic hydrocarbon group having 5 to 20 carbon atoms, which may have a substituent, and one or more of —CH2-'s contained in the alicyclic hydrocarbon group may be substituted with —O—, —S—, or —NH—, it should be noted that in a case where a3 is 2, a plurality of A5's may be the same as or different from each other,
• SP5 represents a single bond, a linear alkylene group having 1 to 12 carbon atoms, a branched alkylene group having 3 to 12 carbon atoms, or a divalent linking group in which one or more of —CH2-'s contained in the linear or branched alkylene group are substituted with —O—, —S—, —NH—, —N(Q)-, or —CO—, where Q represents a substituent,
• L5 represents a polymerizable group, and
• M represents an aromatic ring which does not have a substituent,
• wherein the molecular length A of the polymerizable smectic rod-shaped liquid crystal compound and the molecular length C of the additive refer to values calculated by the following procedure,
• (1) specify the structure of a target compound to be calculated,
• (2) save a file in which the chemical formula of the target compound is created in a “MDLMolfile format”,
• (3) open the saved MDLMolfile format file with a molecular modeling application, and optimize the structure by a simple molecular force field method,
• (4) the interatomic distance between both terminals of the target compound after the structural optimization is calculated as a molecular length, and
• wherein the layer interval B of the smectic phase of the optically anisotropic layer refers with the following devices under the following conditions, to a value calculated from an X-ray diffraction pattern derived from a smectic phase order,
• wherein devices and conditions include,
• X-ray diffractometer:
• X-ray diffractometer for thin film structure evaluation,
• Cu beam source:
• 50 kV·300 mA, and
• solar slit:
• 0.45.