JP2009075494A - Liquid crystal composition and optically anisotropic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new liquid crystal composition useful to produce an optically anisotropic material and having good curability. <P>SOLUTION: The liquid crystal composition comprises at least a liquid crystal compound which has a polymerizable group and of which birefringence is in inverse wavelength dispersion in a visible light region, and a polymerization initiator of which absorbance at 405 nm in methanol is ≥100 (ml/g cm). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal composition and an anisotropic material obtained by fixing the alignment of the liquid crystal composition.

Various optically anisotropic materials such as a retardation plate utilizing the orientation of a liquid crystal composition have been proposed. In addition, for the purpose of optimizing optical properties, various kinds of so-called reverse wavelength dispersive liquid crystal compositions in which birefringence decreases on the short wavelength side in the visible light region, and retardation plates using the liquid crystal compositions are various. It has been proposed (see, for example, Patent Documents 1 to 7).
JP 2002-267838 A JP 2003-160540 A JP-A-2005-208414 JP-A-2005-208415 JP-A-2005-208416 JP 2005-289980 A JP 2006-330710 A

However, in practice, when the present inventor uses a liquid crystal material having a reverse wavelength dispersion to obtain a desired alignment state, and the alignment state is fixed by polymerization, the alignment may not be sufficiently fixed, and lightly touched. It was found that scratches would occur just by doing.
An object of the present invention is to provide a novel liquid crystal composition useful for producing an optically anisotropic material.
Another object of the present invention is to provide a liquid crystal composition having good curability, which contains a liquid crystal compound having reverse wavelength dispersion and can fix the alignment of the liquid crystal compound.
Another object of the present invention is to provide an optically anisotropic material having no defects and good durability.

Means for solving the above problems are as follows.
[1] A liquid crystal compound having a polymerizable group and birefringence having a reverse wavelength dispersion in the visible light region, and a polymerization initiator having an extinction coefficient of 100 (ml / g · cm) or more in methanol at a wavelength of 405 nm A liquid crystal composition comprising at least
[2] The liquid crystal composition according to [1], wherein the polymerization initiator is contained in an amount of 0.5 to 4% by mass with respect to the liquid crystal compound.

式中、Ａ¹及びＡ²は各々独立に、−Ｏ−、−ＮＲ−（Ｒは水素原子又は置換基を表す）、−Ｓ−及び−ＣＯ−からなる群から選ばれる基を表し；Ｚは、炭素原子及び第１４〜１６族の非金属原子からなる群から選択される１つ又は２つの原子を表し、式中記載のＣ−Ｃ＝Ｃ−Ｃ又はＣ＝Ｃ−Ｃ＝Ｃと共に５又は６員環を形成し；Ｒ¹、Ｒ²及びＲ³は各々独立に置換基を表し；ｍは０〜４の整数であり；Ｌ¹及びＬ²は各々独立に、単結合又は二価の連結基を表し；Ｘは第１４〜１６族の非金属原子を表し（ただし、Ｘには水素原子又は置換基Ｒ⁴が結合してもよい）；但し、Ｒ、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴の少なくとも１つには、重合性基を有する置換基である。 [3] The liquid crystal composition according to [1] or [2], wherein the liquid crystal compound is a compound represented by the following general formula (1):

In the formula, A ¹ and A ² each independently represent a group selected from the group consisting of —O—, —NR— (R represents a hydrogen atom or a substituent), —S—, and —CO—; Z Represents one or two atoms selected from the group consisting of a carbon atom and a non-metallic atom of Groups 14 to 16, and together with C—C═C—C or C═C—C═C described in the formula Forming a 5- or 6-membered ring; R ¹ , R ² and R ³ each independently represents a substituent; m is an integer from 0 to 4; L ¹ and L ² are each independently a single bond or two X represents a non-metal atom of Groups 14 to 16 (provided that a hydrogen atom or a substituent R ⁴ may be bonded to X); provided that R, R ¹ , R ² , R ³ and R ⁴ are substituents having a polymerizable group.

[4] An optically anisotropic material obtained by curing the liquid crystal composition according to any one of [1] to [3].

ADVANTAGE OF THE INVENTION According to this invention, the novel liquid crystal composition useful for preparation of an optically anisotropic material can be provided.
In addition, according to the present invention, it is possible to provide a liquid crystal composition having a good curability that contains a liquid crystal compound having a reverse wavelength dispersion and that can fix the alignment of the liquid crystal compound.
Furthermore, according to the present invention, an optically anisotropic material having no defects and good durability can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

  The present invention is described in detail below. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

  In the present specification, Re (λ) and Rth (λ) represent in-plane retardation (nm) and retardation in the thickness direction (nm) at wavelength λ, respectively. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (trade name, manufactured by Oji Scientific Instruments).

When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (if there is no slow axis, Rth (λ) With respect to the film normal direction (with an arbitrary direction as the rotation axis), the light of wavelength λ nm is incident from each inclined direction in steps of 10 degrees from the normal direction to 50 degrees on one side, and a total of 6 points are measured. It is calculated in KOBRA 21ADH or WR based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.

In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated in KOBRA 21ADH or WR after changing its sign to negative.
In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (in the absence of the slow axis, the arbitrary direction in the film plane is the rotation axis), Based on the value, the assumed value of the average refractive index, and the input film thickness value, Rth can also be calculated by the following formulas (1) and (2).

  In the formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction perpendicular to nx in the plane, and nz represents the refractive index in the direction perpendicular to nx and ny. d represents the film thickness of the film.

In the case where the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film without a so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is the above-mentioned Re (λ), and the in-plane slow axis (determined by KOBRA 21ADH or WR) is the tilt axis (rotary axis), and −50 ° to + 50 ° with respect to the film normal 11 points of light having a wavelength of λ nm are incident from the inclined direction in 10 degree steps until KOBRA 21ADH is measured based on the measured retardation value, the assumed average refractive index, and the input film thickness value. Or it is calculated by WR.

In the above measurement, as the assumed value of the average refractive index, the values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).
By inputting the assumed value of the average refractive index and the film thickness, nx, ny, and nz are calculated in KOBRA 21ADH or WR. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

[Definition of Δn]
Δn indicates anisotropy with respect to polarized light, and is described in detail in “Liquid Crystal Handbook” (Maruzen Co., Ltd., 2000), Chapter 2, 2.3 Physical Properties. When linearly polarized light passes, the difference between the refractive index (no) when the polarization direction is perpendicular to the anisotropic axis and the refractive index (ne) when the polarization direction is parallel to the anisotropic axis is represented by Δn.
[Definition of chromatic dispersion of Δn]
Δn generally varies depending on the measurement wavelength. This is because the aforementioned no and ne differ depending on the wavelength, and the chromatic dispersion of Δn indicates the wavelength dependence of the difference in refractive index between no and ne. Details are described in “Liquid Crystal Handbook” (Maruzen Co., Ltd., 2000), Chapter 2, 2.4.13. In the present invention, Δn (450), Δn (550), and Δn (650) may be expressed, and Δn at 450 nm, 550 nm, and 650 nm, respectively. However, each measurement wavelength may include an error of ± 10 nm.

Examples of the method for measuring Δn of liquid crystal include a method using a wedge-shaped liquid crystal cell as described in “Liquid Crystal Handbook” 2.4.13 (Maruzen Co., Ltd., 2000). In this method, Δn of each wavelength is obtained by using three types of band-pass filters of 450 nm, 550 nm, and 650 nm.
When the liquid crystal compound used as a sample has a polymerizable group, a polymerization reaction may occur in a wedge-shaped liquid crystal cell, and measurement may be difficult. In such a case, it is preferable to measure by adding a polymerization inhibitor. In addition, in a state where the liquid crystal is uniformly aligned, Re is obtained at each wavelength by measuring with a device capable of measuring a phase difference such as KOBRA (trade name, manufactured by Oji Scientific Instruments Co., Ltd.). By separately measuring the thickness, Δn can be obtained (from the formula of Δn = Re / d (film thickness)).

[Definition of order and reverse in chromatic dispersion of Δn]
In general, the refractive index of a substance increases with decreasing wavelength. The liquid crystal compound follows this, and the refractive index of no and ne increases as the measurement wavelength is shorter. However, since Δn is the difference between no and ne, when the wavelength dispersions of no and ne are different, there are cases where the wavelength dispersion of Δn is large on the short wavelength side and small on the short wavelength side. In general, the short wavelength side is often large, and the case where the short wavelength side is large is called forward dispersion. In the chromatic dispersion of Δn, the case where the short wavelength side is small is called reverse dispersion.
[Definition of chromatic dispersion in optically anisotropic material]
In an optical compensation material or the like, the optical anisotropy is represented by Re or Rth and is defined as described above. When the wavelength dependence of Re or Rth is called chromatic dispersion in Re (λ) or Rth (λ), and the short wavelength side is larger in chromatic dispersion. Is called forward dispersion, and the case where the short wavelength side is small is called reverse dispersion.

[Liquid crystal composition]
First, the liquid crystal composition of the present invention will be described. The liquid crystal composition of the present invention includes a liquid crystal compound having a polymerizable group and birefringence having a reverse wavelength dispersion in the visible light region, and a polymerization having an extinction coefficient at 405 nm in methanol of 100 (ml / g · cm) or more. It contains at least an initiator. In general, liquid crystal compounds that are inversely dispersive in birefringence in the visible light region have a common feature that they have a partial structure that absorbs light in the long wavelength region in a direction perpendicular to the molecular long axis. Therefore, there are many compounds having an absorption maximum in the ultraviolet region (wavelength of about 340 to 380 nm) in the vicinity of the visible region. On the other hand, most of the photopolymerization initiators absorb radical light to generate radicals, but when used in combination with the above-mentioned characteristic compound, the radical generation rate may decrease, resulting in the orientation. The state may not be fixed enough. In the present invention, a liquid crystal composition having sufficient curability is provided by using a reverse wavelength dispersible liquid crystal compound and a polymerization initiator having an extinction coefficient at a wavelength of 405 nm within a predetermined range.

<Polymerization initiator>
The polymerization initiator used in the present invention (hereinafter sometimes simply referred to as “initiator”) has an extinction coefficient in a methanol solution at a measurement wavelength of 405 nm of 100 (ml / g · cm) or more. The upper limit is not particularly limited, but the same extinction coefficient of the polymerization initiator is generally 10000 ml / g · cm or less. In the present invention, the same extinction coefficient of the initiator is preferably 100 to 5000 (ml / g · cm), and more preferably 100 to 2000 (ml / g · cm). As long as this property is satisfied, the molecular structure and the like are not particularly limited. A preferred group of compounds includes acylphosphine oxides and titanocenes. Particularly preferred are acylphosphine oxides which are excellent in handling under yellow light. Commercial products may be used as the initiator, and specific examples include IRGACURE-369, IRGACURE-819, IRGACURE-1700, IRGACURE-1800, IRGACURE-1850, IRGACURE-4265, IRGACURE-784 manufactured by Ciba Specialty Chemicals. Is mentioned.

  The initiator concentration of the sample used for measuring the extinction coefficient is preferably about 0.1 g to 10 g / l (liter). When the initiator is insoluble or hardly soluble in methanol, a sample solution can be prepared by dissolving the initiator in a soluble solvent and diluting with methanol.

<Liquid crystal compound>
In the present invention, a liquid crystal compound whose birefringence (Δn) is reverse wavelength dispersion in the visible light region is used. Here, the liquid crystal compound in which Δn is reverse wavelength dispersion means a compound that is smaller as Δn is shorter. Specifically, Δn (450), Δn (550), and Δn (650) are obtained by the above-described method, and Δn (450) / Δn (550), Δn (550) / Δn (650), and Δn (450) are obtained. A compound in which at least one of / Δn (650) is smaller than 1. Examples of liquid crystal compounds in which Δn is reverse wavelength dispersion include Japanese Patent Application Laid-Open Nos. 2002-267838, 2003-160540, 2005-208414, 2005-208415, 2005-208416, The compounds described in 2005-289980, 2006-243470, 2006-284903, 2006-330710, and International Patent (WO) 2006-112338 pamphlets are included. Especially, the compound represented by the following general formula (1) is preferable, and the compound represented by the following general formula (2) is more preferable.

In the formula, A ¹ and A ² each independently represent a group selected from the group consisting of —O—, —NR— (R represents a hydrogen atom or a substituent), —S—, and —CO—. Z represents one or two atoms selected from the group consisting of a carbon atom and a non-metal atom of Groups 14 to 16, and C—C═C—C or C═C—C═C described in the formula Together with it forms a 5- or 6-membered ring. R ¹ , R ² and R ³ each independently represents a substituent. m is an integer of 0-4. L ¹ and L ² each independently represents a single bond or a divalent linking group. X represents a nonmetallic atom belonging to Groups 14 to 16 (however, a hydrogen atom or a substituent R ⁴ may be bonded to X). At least one of R, R ¹ , R ² , R ³ and R ⁴ is a substituent having a polymerizable group.

In the formula, A ¹ , A ² , Z, R ¹ , R ² , R ³ , m, L ¹ and L ² are the same as those in the general formula (1). R ⁵ and R ⁶ each independently represents a substituent. Note that at least one of R, R ¹ , R ² , R ³ , R ⁵ and R ⁶ is a substituent having a polymerizable group.

In the general formula (1) or (2), the divalent linking group represented by L ¹ and L ² is not particularly limited, but preferably includes the following examples. In addition, regarding the bonding position, the bonding position between the Z and the 5- to 6-membered ring formed by C—C═C—C or C═C—C═C is on the left side of the linking group exemplified below. Shall.

L ¹ and L ² are more preferably —O—, —COO—, and —OCO—, respectively.

In the general formula (1) or (2), Z represents one or two atoms selected from the group consisting of a carbon atom and a nonmetal atom of Group 14 to 16, and C—C in the formula Forms a 5- or 6-membered ring with ═C—C or C═C—C═C. Although it does not specifically limit as a 5-6 membered ring formed by Z and CC = C-C or C = C-C = C, The following example is mentioned as a preferable example. In the following example, the dotted line represents binding to L ¹ or L ² .

The ring formed by Z and C—C═C—C or C═C—C═C is preferably a 6-membered ring. By using a 6-membered ring, it becomes possible to align with a higher degree of alignment order. For the same reason, it is preferably an aromatic ring, more preferably an aromatic ring and a 6-membered ring.
From these viewpoints and synthetic viewpoints, the ring formed by Z and C—C═C—C or C═C—C═C is preferably a thiophene ring, a benzene ring, or a pyridine ring, and the benzene ring is most preferred. preferable.

In general formula (1) or (2), R ¹ is a substituent, and when a plurality of R ¹ are present, they may be the same or different and may form a ring. The following are mentioned as an example of a substituent.

  A halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group (preferably a linear, branched or unsubstituted alkyl group having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group), cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl group) , Cyclopentyl group, 4-n-dodecylcyclohexyl group), bicycloalkyl group (preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, that is, one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms. Monovalent groups removed, for example, bicyclo [1,2,2] heptan-2-yl group, bicyclo [2,2 2] octan-3-yl group),

An alkenyl group (preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, such as a vinyl group or an allyl group), a cycloalkenyl group (preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, That is, it is a monovalent group in which one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms is removed, for example, a 2-cyclopenten-1-yl, 2-cyclohexen-1-yl group), a bicycloalkenyl group (substituted or substituted). An unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group in which one hydrogen atom of a bicycloalkene having one double bond is removed. Bicyclo [2,2,1] hept-2-en-1-yl group, bicyclo [2,2,2] oct-2-en-4-yl group), alkini Group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as ethynyl group, propargyl group),

An aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, such as a phenyl group, a p-tolyl group, a naphthyl group), a heterocyclic group (preferably a 5- or 6-membered substituted or unsubstituted, aromatic A monovalent group obtained by removing one hydrogen atom from an aromatic or non-aromatic heterocyclic compound, and more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms. 2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group), cyano group, hydroxyl group, nitro group, carboxyl group, alkoxy group (preferably substituted or unsubstituted having 1 to 30 carbon atoms) Alkoxy groups such as methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group), aryloxy group (preferably Or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, such as phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy. Group),

A silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms, such as trimethylsilyloxy group or tert-butyldimethylsilyloxy group), a heterocyclic oxy group (preferably a substituted or unsubstituted heterocycle having 2 to 30 carbon atoms) Ring oxy group, 1-phenyltetrazole-5-oxy group, 2-tetrahydropyranyloxy group), acyloxy group (preferably formyloxy group, substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, carbon number 6-30 substituted or unsubstituted arylcarbonyloxy groups such as formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy group), carbamoyloxy group (preferably , C1-C30 substitution or non-placement Carbamoyloxy group, for example, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyl An oxy group), an alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, such as a methoxycarbonyloxy group, an ethoxycarbonyloxy group, a tert-butoxycarbonyloxy group, and an n-octylcarbonyloxy group. Group), an aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, such as phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group, pn- Hexadecyl oxy phenoxycarbonyl group),

An amino group (preferably an amino group, a substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted anilino group having 6 to 30 carbon atoms, such as an amino group, a methylamino group, a dimethylamino group; , Anilino group, N-methyl-anilino group, diphenylamino group), acylamino group (preferably formylamino group, substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, substituted or unsubstituted 6 to 30 carbon atoms, or Unsubstituted arylcarbonylamino group, for example, formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group), aminocarbonylamino group (preferably substituted or unsubstituted amino having 1 to 30 carbon atoms) Carbonylamino group, for example, carbamoylamino group, N, N-dimethylaminocarbonyl Mino group, N, N-diethylaminocarbonylamino group, morpholinocarbonylamino group), alkoxycarbonylamino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, such as methoxycarbonylamino group, ethoxycarbonylamino Group, tert-butoxycarbonylamino group, n-octadecyloxycarbonylamino group, N-methyl-methoxycarbonylamino group), aryloxycarbonylamino group (preferably substituted or unsubstituted aryloxycarbonyl having 7 to 30 carbon atoms) Amino groups such as phenoxycarbonylamino group, p-chlorophenoxycarbonylamino group, mn-octyloxyphenoxycarbonylamino group),

Sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as sulfamoylamino group, N, N-dimethylaminosulfonylamino group, Nn-octylamino Sulfonylamino group), alkyl or arylsulfonylamino group (preferably substituted or unsubstituted alkylsulfonylamino group having 1 to 30 carbon atoms, substituted or unsubstituted arylsulfonylamino group having 6 to 30 carbon atoms, for example, methylsulfonyl An amino group, a butylsulfonylamino group, a phenylsulfonylamino group, a 2,3,5-trichlorophenylsulfonylamino group, a p-methylphenylsulfonylamino group, a mercapto group, and an alkylthio group (preferably a substituent having 1 to 30 carbon atoms) Or an unsubstituted alkylthio group such as a methylthio group Ethylthio group, n-hexadecylthio group), arylthio group (preferably a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, for example, phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group), heterocyclic thio A group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, such as 2-benzothiazolylthio group, 1-phenyltetrazol-5-ylthio group),

Sulfamoyl group (preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms such as N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group , N-acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N′-phenylcarbamoyl) sulfamoyl group), sulfo group, alkyl or arylsulfinyl group (preferably substituted with 1 to 30 carbon atoms or Unsubstituted alkylsulfinyl group, substituted or unsubstituted arylsulfinyl group having 6 to 30 carbon atoms, such as methylsulfinyl group, ethylsulfinyl group, phenylsulfinyl group, p-methylphenylsulfinyl group), alkyl or arylsulfonyl group ( Preferably, it is substituted or substituted with 1 to 30 carbon atoms. Unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group having 6 to 30 carbon atoms, e.g., methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group, p- methylphenyl sulfonyl group),

An acyl group (preferably a formyl group, a substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, such as an acetyl group or a pivaloylbenzoyl group), Aryloxycarbonyl group (preferably a substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms, such as phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, p-tert-butylphenoxy Carbonyl group), alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms, such as methoxycarbonyl group, ethoxycarbonyl group, tert-butoxycarbonyl group, n-octadecyloxycarbonyl group), carbamoyl Group (preferred Is a substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, such as a carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- ( Methylsulfonyl) carbamoyl group),

An aryl or heterocyclic azo group (preferably a substituted or unsubstituted arylazo group having 6 to 30 carbon atoms, a substituted or unsubstituted heterocyclic azo group having 3 to 30 carbon atoms, such as a phenylazo group, a p-chlorophenylazo group, 5-ethylthio-1,3,4-thiadiazol-2-ylazo group), imide group (preferably N-succinimide group, N-phthalimide group), phosphino group (preferably substituted or non-substituted having 2 to 30 carbon atoms) Substituted phosphino groups such as dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group), phosphinyl groups (preferably substituted or unsubstituted phosphinyl groups having 2 to 30 carbon atoms such as phosphinyl group, dioctyl Oxyphosphinyl group, diethoxyphosphinyl group), phosphinyloxy group (preferably carbon A substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms, such as a diphenoxyphosphinyloxy group or a dioctyloxyphosphinyloxy group, or a phosphinylamino group (preferably having 2 to 30 carbon atoms) A substituted or unsubstituted phosphinylamino group such as a dimethoxyphosphinylamino group or a dimethylaminophosphinylamino group, a silyl group (preferably a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, such as , Trimethylsilyl group, tert-butyldimethylsilyl group, phenyldimethylsilyl group)

  Among the above substituents, those having a hydrogen atom may be substituted with the above groups after removing this. Examples of such functional groups include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Specific examples thereof include a methylsulfonylaminocarbonyl group, a p-methylphenylsulfonylaminocarbonyl group, an acetylaminosulfonyl group, and a benzoylaminosulfonyl group.

  R1 is preferably a halogen atom, alkyl group, alkenyl group, aryl group, heterocyclic group, hydroxyl group, carboxyl group, alkoxy group, aryloxy group, acyloxy group, cyano group or amino group, more preferably a halogen atom. , An alkyl group, a cyano group or an alkoxy group.

When a plurality of R ¹ are present and form a ring with each other, the ring is preferably a 5- to 8-membered ring, more preferably a 5- or 6-membered ring. Most preferred is a 6-membered ring.

In the general formula (1) or (2), m represents the number of substitutions of R ¹ , and can be taken by a ring structure formed by Z and C—C═C—C or C═C—C═C. The number changes. When m is 0 at the minimum, Z represents two carbon atoms, and the ring formed by Z and C—C═C—C or C═C—C═C has no aromaticity The maximum is 4. m is preferably 0 or 1, more preferably 0.

In the general formula (1) or (2), R ² and R ³ each independently represent a substituent. An example of R ¹ is given as an example. R ² and R ³ are the longitudinal direction of the molecule in the compound represented by the general formula (1) or (2).
The compound represented by the general formula (1) or (2) preferably exhibits liquid crystallinity. As an element to develop liquid crystallinity, as described in “Liquid Crystal Handbook” (Maruzen) Chapter 3 “Molecular Structure and Liquid Crystallinity”, a rigid part called a core and a flexible part called a side chain are required. It is. Therefore, it is preferable that at least one rigid part, that is, a cyclic part exists as a substituent for R ² and R ³ . R ² and R ³ are preferably a substituted or unsubstituted phenyl group or a substituted or unsubstituted cyclohexyl group. Preferred are a phenyl group having a substituent and a cyclohexyl group having a substituent, and more preferred are a phenyl group having a substituent at the 4-position and a cyclohexyl group having a substituent at the 4-position. More preferably, a phenyl group having a benzoyloxy group having a substituent at the 4-position at a 4-position, a phenyl group having a cyclohexyl group having a substituent at the 4-position at a 4-position, and a phenyl group having a substituent at the 4-position being at the 4-position And a cyclohexyl group having a cyclohexyl group having a substituent at the 4-position at the 4-position.

  Further, the cyclohexyl group having a substituent at the 4-position includes a cis isomer and a trans isomer, but the isomer is not limited in the present invention, and a mixture of both may be used. A trans-cyclohexyl group is preferred.

In the general formula (1) or (2), R ⁵ and R ⁶ each independently represents a substituent. Examples of the substituents which the R ¹ represents may be mentioned as examples. At least one of R ⁵ and R ⁶ is preferably an electron-withdrawing substituent having a Hammett's substituent constant σp value greater than 0, and having an electron-withdrawing substituent having a σp value of 0 to 1.5. More preferably. Examples of such a substituent include a trifluoromethyl group, a cyano group, a carbonyl group, and a nitro group. R ⁵ and R ⁶ may be bonded to form a ring.
As for Hammett's substituent constants σp and σm, for example, Naoki Inamoto, “Hammett's rule-structure and reactivity-” (Maruzen), edited by the Chemical Society of Japan, “New Experimental Chemistry Course 14 Synthesis and Reaction of Organic Compounds V” 2605 (Maruzen), Tadao Nakatani, “Explanation on Theoretical Organic Chemistry”, page 217 (Tokyo Kagaku Dojin), “Chemical Review”, 91, 165-195 (1991).
As the ring R ⁵ and R ⁶ form attached, according to T.H.James al, The Theory of The Photografic Process 4 th edition (1977 year Macmillan Publishing Press) 199 pages Table 8.2 An acidic heterocyclic group is preferred.

In the general formula (1) or (2), A ¹ and A ² are each independently from the group consisting of —O—, —NR— (where R is a hydrogen atom or a substituent), —S—, and —CO—. Represents a selected group. Preferably -O -, - NR- (. R represents a substituent, examples Examples of the R ¹ and the like) or -S-.

In the general formula (1), X represents a nonmetallic atom belonging to Groups 14-16. However, a hydrogen atom or a substituent may be bonded to X. X is preferably ═O, ═S, ═NR ⁴ , ═C (R ⁵ ) R ⁶ (wherein R ⁴ , R ⁵ , and R ⁶ each independently represent a substituent, and examples of the above R1 include ).

The liquid crystal compound of the present invention has a polymerizable group. Thereby, when it uses for preparation of optically anisotropic materials, such as a phase difference plate, the change of the phase difference by a heat | fever etc. can be prevented. The polymerizable group is preferably located at the end of the compound molecule.
In the general formula (1), at least one of R, R ¹ , R ² , R ³ and R ⁴ , and in the general formula (2), R, R ¹ , R ² , R ³ , R ⁵ and R ⁶ One is a substituent having a polymerizable group. The number of substituents in the molecule of the liquid crystal compound is preferably 1 to 6, more preferably 1 to 4, and still more preferably 1 to 3. The preferred substituents for the polymerizable group are R ² , R ³ and R ⁴ in the general formula (1), and R ² , R ³ , R ⁵ and R in the general formula (2). ⁶ .

  The polymerizable group is preferably a group capable of addition polymerization reaction or condensation polymerization reaction. Such a polymerizable group is preferably a polymerizable ethylenically unsaturated group or a ring-opening polymerizable group. Examples of polymerizable groups are shown below.

Furthermore, the polymerizable group is particularly preferably a functional group capable of addition polymerization reaction. Such a polymerizable group is preferably a polymerizable ethylenically unsaturated group or a ring-opening polymerizable group.
The polymerizable group is preferably a group represented by any of the following general formulas P1, P2, P3, or P4.

In the formula, R ⁵¹¹ , R ⁵¹² , R ⁵¹³ , R ⁵²¹ , R ⁵²² , R ⁵²³ , R ⁵³¹ , R ⁵³² , R ⁵³³ , R ⁵⁴¹ , R ⁵⁴² , R ⁵⁴³ , R ⁵⁴⁴ , and R ⁵⁴⁵ are each independently Represents a hydrogen atom or an alkyl group. n represents 0 or 1.

R ⁵¹¹ , R ⁵¹² and R ⁵¹³ of the polymerizable group P 1 each independently represent a hydrogen atom or an alkyl group.
The alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group residue formed by substitution of the polymerizable group P1 is an alkyleneoxy group (for example, alkyleneoxy such as ethyleneoxy, propyleneoxy, butyleneoxy, pentyleneoxy, hexyleneoxy, heptyleneoxy, etc.) Oxy groups, substituted alkyleneoxy groups containing ether bonds such as ethyleneoxyethoxy), alkyleneoxycarbonyloxy groups (for example, ethyleneoxycarbonyloxy, propyleneoxycarbonyloxy, butyleneoxycarbonyloxy, pentyleneoxycarbonyloxy, hexyleneoxy) Alkyleneoxycarbonyloxy groups such as carbonyloxy and heptyleneoxycarbonyloxy, and ethers such as ethyleneoxyethoxycarbonyloxy A substituted alkyleneoxycarbonyloxy group containing a bond), an alkyleneoxycarbonyl group (for example, ethyleneoxycarbonyl group, propyleneoxycarbonyl group, butyleneoxycarbonyl group, pentyleneoxycarbonyl group, hexyleneoxycarbonyl group, heptyleneoxycarbonyl group) A substituted alkyleneoxycarbonyl group containing an ether bond such as an alkyleneoxycarbonyl group or an ethyleneoxyethoxycarbonyl group). The polymerizable group P1 may be directly bonded to the aromatic ring.

n represents an integer of 0 to 1, and n is preferably 1. When n is 1, the polymerizable group P1 represents a substituted or unsubstituted vinyl ether group. R ⁵¹¹ and R ⁵¹³ are each independently a hydrogen atom or an alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, etc. An alkyl group is preferred, and methyl is more preferred), and R ⁵¹¹ is a methyl group and R ⁵¹³ is a hydrogen atom, or a combination of R ⁵¹¹ and R ⁵¹³ are both hydrogen atoms.

R ⁵¹² represents a hydrogen atom, a substituted or unsubstituted alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, 2-chloroethyl, 3-methoxyethyl, methoxyethoxy And a lower alkyl group such as methyl and ethyl is preferable, and methyl is more preferable.], A hydrogen atom and a lower alkyl group are preferable, and a hydrogen atom is more preferable. Accordingly, as the polymerizable group P1, an unsubstituted vinyloxy group which is a functional group having high polymerization activity is generally preferably used.

The polymerizable group P2 represents a substituted or unsubstituted oxirane group. R ⁵²¹ and R ⁵²² are each independently a hydrogen atom or an alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, etc., and lower groups such as methyl and ethyl). An alkyl group is preferred, and methyl is more preferred), and both R ⁵²¹ and R ⁵²² are preferably hydrogen atoms.

R ⁵²³ is a hydrogen atom, a substituted or unsubstituted alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, 2-chloroethyl, 3-methoxyethyl, methoxyethoxy And a lower alkyl group such as methyl or ethyl is preferable, and methyl is more preferable. A hydrogen atom or a lower alkyl group such as methyl, ethyl or n-propyl is preferable.

The polymerizable group P3 represents a substituted or unsubstituted acrylic group. Substituents R ⁵³¹ and R ⁵³³ each independently represent a hydrogen atom or an alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, methyl, ethyl, etc. R ⁵³¹ is methyl and R ⁵³³ is a hydrogen atom, or a combination of R ⁵³¹ and R ⁵³³ are both hydrogen atoms.

R ⁵³² is a hydrogen atom, a substituted or unsubstituted alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, 2-chloroethyl, 3-methoxyethyl, methoxyethoxy Ethyl, and lower alkyl groups such as methyl and ethyl are preferred, and methyl is more preferred), and a hydrogen atom is preferred. Accordingly, as the polymerizable group P3, generally, a functional group having high polymerization activity such as an unsubstituted acryloxy group, methacryloxy group, crotonyloxy is preferably used.

The polymerizable group P4 represents a substituted or unsubstituted oxetane group. R ⁵⁴² , R ⁵⁴³ , R ⁵⁴⁴ and R ⁵⁴⁵ are each independently a hydrogen atom or an alkyl group (eg, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, methyl And lower alkyl groups such as ethyl are preferable, and methyl is more preferable.), And R ⁵⁴² , R ⁵⁴³ , R ⁵⁴⁴ and R ⁵⁴⁵ are all preferably hydrogen atoms.

R ⁵⁴¹ is a hydrogen atom, a substituted or unsubstituted alkyl group (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, pentyl, hexyl, heptyl, octyl, nonyl, 2-chloroethyl, 3-methoxyethyl, methoxyethoxy And a lower alkyl group such as methyl or ethyl is preferable, and methyl is more preferable. A hydrogen atom or a lower alkyl group such as methyl, ethyl or n-propyl is preferable.

  Specific examples of the compound represented by the general formula (1) or (2) are shown below, but the present invention is not limited to the following specific examples.

The preferable range of the wavelength dispersion of Δn cannot be uniquely limited because the preferable range varies depending on the use of the liquid crystal compound. However, more preferable ranges of the wavelength dispersion of Δn include the following formulas (4) and (5). ) Is preferably satisfied.
(4) 0.60 <Δn (450 nm) / Δn (550 nm) <0.99
(5) 1.01 <Δn (650 nm) / Δn (550 nm) <1.35

The liquid crystal compound of the present invention may have either positive or negative birefringence, but preferably has positive birefringence.
The liquid crystal phase having positive birefringence is described in detail in Chapter 2 of “Liquid Crystal Handbook” (Maruzen Co., Ltd., 2000). For example, a nematic phase, a cholesteric phase, a smectic phase (for example, (Smectic A phase, smectic C phase).

  In the case where the liquid crystal compound of the present invention is used for forming an optically anisotropic film, those showing good monodomain properties are preferable for uniform alignment without defects. When the monodomain property is poor, the resulting structure becomes a polydomain, an orientation defect occurs at the boundary between domains, and light is scattered. This is not preferable because it leads to a decrease in the transmittance of the optically anisotropic layer. In order to exhibit good monodomain properties, the liquid crystal compound of the present invention preferably exhibits a nematic phase (N phase) or a smectic A phase (SA phase). In particular, it is preferable to develop a nematic phase.

  The liquid crystal compound may be a low-molecular liquid crystal compound or a high-molecular liquid crystal compound, but the low-molecular liquid crystal compound is preferred in consideration of the ease of alignment of the liquid crystal.

  There is no restriction | limiting in particular about the content rate of each component of the liquid-crystal composition of this invention, It can determine according to a use, the kind of each component, etc. When the liquid crystal composition of the present invention is used for forming an optically anisotropic film, the polymerization initiator is preferably contained in an amount of 0.5 to 4% by mass, more preferably 1 to 4% by mass with respect to the liquid crystal compound. Is more preferable.

  The liquid crystal composition of the present invention may contain a plurality of liquid crystal compounds in which the birefringence is reverse wavelength dispersion. In addition, one or more liquid crystal compounds whose forward refraction is birefringence in the visible light region may be contained. Preferable examples of the forward wavelength dispersion liquid crystal compound include compounds described in JP-A Nos. 2005-301235 and 2002-62427.

The liquid crystal composition of the present invention can be used for production of various optically anisotropic materials. Hereinafter, an optically anisotropic film formed using the liquid crystal composition of the present invention will be described in detail as an example.
[Optically anisotropic film]
An optically anisotropic film can be formed by disposing the liquid crystal composition of the present invention on the surface (for example, the surface of an alignment film), and fixing the liquid crystal compound molecules in a desired alignment state. it can. The liquid crystal compound preferably exhibits a nematic phase or a smectic phase alone or in the presence of other additives. The liquid crystal composition may contain at least one additive in addition to the liquid crystal compound and the polymerization initiator. The liquid crystal composition is nematic in a temperature range in which the orientation is fixed in a state containing an additive to be added as desired (for example, in the form of a coating solution containing a solvent, in which the solvent is volatilized in the process of heat drying). It preferably exhibits a phase, a smectic phase, or a cholesteric phase.

"Additive"
-Alignment accelerator In the liquid-crystal composition, an additive (alignment accelerator) capable of accelerating the alignment of molecules of the liquid crystal compound may be added. The content of the alignment accelerator is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and 0.05 to 4% by mass with respect to the liquid crystal compound. Is more preferable. The alignment accelerator contributes to aligning the molecules of the liquid crystalline compound by the excluded volume effect or electrostatic effect at the air interface or alignment film interface. The compounds described in JP 2002-20363 A and JP 2002-129162 A can be used. Also, paragraph numbers [0072] to [0075] of Japanese Patent Application Laid-Open No. 2004-53981, paragraph numbers [0071] to [0078] of Japanese Patent Application Laid-Open No. 2004-4688, and paragraphs of Japanese Patent Application Laid-Open No. 2004-139015. The matters described in the numbers [0052] to [0054], [0065] to [0066], and [0092] to [0094] can be appropriately applied to the present invention.

Chain transfer agent A chain transfer agent may be added to the liquid crystal composition. The content of the chain transfer agent is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and 0.05 to 4% by mass with respect to the liquid crystal compound. More preferably. As the specific chain transfer agent, generally known ones can be used, but preferably a compound having a mercapto group (thiol compound such as dodecyl mercaptan, octyl mercaptan, trimethylolpropane tris (3-mercaptopropionate). ), Pentaerythritol tetrakis (3-mercaptopropionate, etc.) and disulfide compounds (for example, diphenyl disulfide, etc.). Compatibility with the liquid crystal compound is also required, and a thiol compound exhibiting liquid crystallinity is more preferable from the viewpoint of compatibility. Examples of the thiol compound exhibiting liquid crystallinity include compounds described in US Pat. No. 6,096,241.

Other additives The liquid crystal composition may contain other additives such as a plasticizer, a surfactant, a polymerizable monomer, etc., as long as the effects of the present invention are not impaired. These materials are added for various purposes, for example, for the purpose of fixing the orientation, improving the uniformity of the coating film, the strength of the film, and the orientation of the liquid crystal compound. These materials are preferably compatible with the liquid crystal compound used in combination and do not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the above-described polymerizable group-containing liquid crystal compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 1 to 30% by mass with respect to the liquid crystalline compound.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specific examples include compounds described in paragraph numbers [0028] to [0056] in JP-A-2001-330725.

  The polymer used together with the liquid crystal compound is preferably capable of thickening the coating solution. A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and in the range of 0.1 to 8% by mass with respect to the liquid crystal molecules so as not to inhibit the alignment of the liquid crystal compound. It is more preferable.

"solvent"
The liquid crystal composition may be prepared as a coating solution. As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides, esters and ketones are preferred, and esters and ketones are particularly preferred. Two or more organic solvents may be used in combination.
The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

Fixing the alignment state of the liquid crystal compound can be carried out by a polymerization reaction of the polymerizable compound. For the polymerization reaction carried out for immobilization, it is preferable to use a photopolymerization reaction using a photopolymerization initiator. It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. Further, the polymerization may be carried out by reducing the oxygen concentration.

  The thickness of the optically anisotropic film is preferably 0.1 to 10 μm, more preferably 0.2 to 5 μm, and most preferably 0.5 to 5 μm.

  When the uniformity of orientation before polymerization is examined in detail, it is preferable that after applying the composition, the composition is kept in a nematic phase or an isotropic phase and then cooled to a smectic phase. The temperature above the transition temperature to the smectic phase is preferably 0.1 ° or higher, more preferably 1 ° or higher, and further preferably 5 ° to 20 °. The heat treatment time in the nematic phase or isotropic phase is preferably maintained for 10 seconds or more, more preferably 20 seconds or more, and further preferably 30 seconds or more and 3 minutes or less.

《Alignment film》
An alignment film may be used for the production of the optically anisotropic film. The alignment film has a function of regulating the alignment direction of the liquid crystalline molecules. Furthermore, the alignment film is used for the purpose of improving the uniformity of alignment and improving the adhesion between the polymer substrate used as a support and the optically anisotropic film. Note that if the alignment state of the liquid crystalline compound is fixed after the alignment, the alignment film plays the role and can be removed. That is, only the optically anisotropic film on the alignment film in which the alignment state is fixed may be transferred onto another support or a polarizer.

  The alignment film is an organic compound (for example, ω) by rubbing treatment on the surface of the organic compound (preferably polymer) film, oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodgett method (LB film). -Tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearylate). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known.

  For the alignment film, it is preferable to use a polymer whose side chain has a function of aligning liquid crystal molecules, and it is also preferable to use a polymer having a crosslinkable functional group (eg, double bond) in the side chain. . The crosslinkable functional group may have a function of aligning liquid crystal molecules. In addition, the alignment film may be a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent, and a plurality of combinations thereof can be used.

  Examples of the alignment film polymer include, for example, a methacrylate polymer, a styrene polymer, a polyolefin, a polyvinyl alcohol, a modified polyvinyl alcohol, and a poly (N--N) described in paragraph No. [0022] of JP-A-8-338913. Methylolacrylamide), polyester, polyimide, vinyl acetate polymer, carboxymethylcellulose, polycarbonate and the like. Silane coupling agents can be used as the polymer. Water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are most preferred. . It is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization.

  The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000.

  A side chain having a function of aligning liquid crystal molecules generally has a hydrophobic group as a functional group. The specific type of functional group is determined according to the type of liquid crystal molecule and the required alignment state. For example, the modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Examples include substituted hydrocarbon groups, thioether groups, polymerizability (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy, dialkoxy, monoalkoxy), and the like. As specific examples of these modified polyvinyl alcohol compounds, for example, paragraph numbers [0022] to [0145] in JP-A No. 2000-155216 and paragraph numbers [0018] to [0018] in JP-A No. 2002-62426 are described. [0022] and the like.

When the alignment film polymer has a crosslinkable functional group in the side chain, a bond may be formed between the alignment film polymer and the optically anisotropic film formed on the alignment film. It is preferable when an optically anisotropic film is used as the laminate.
The crosslinkable functional group of the alignment film polymer preferably includes a polymerizable group. Specific examples include those described in paragraphs [0080] to [0100] in JP-A-2000-155216.

The polymer for alignment film may be crosslinked using a crosslinking agent.
Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to the polymer for alignment films, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, sufficient durability without the occurrence of reticulation can be obtained even when left in a high temperature and high humidity atmosphere for a long period of time.

  The alignment film is basically required to apply the above-mentioned polymer, which is an alignment film forming material, and optionally a composition containing a crosslinking agent to the surface of a support such as a polymer film, followed by drying by heating (crosslinking). It can be formed by rubbing. As described above, the crosslinking reaction may be performed at any time after the application. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating solution is preferably a mixed solvent of an organic solvent (eg, methanol) having a defoaming action and water. The ratio by mass is water: methanol greater than 0 and 99 or less: less than 100, preferably 1 or more, and more preferably greater than 0 and 91 or less: less than 100, 9 or more. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the film | membrane surface of the orientation film and also the optically anisotropic film | membrane formed on it is reduced significantly.

  The coating method for forming the alignment film is preferably a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a rod coating method or a roll coating method. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heat drying can be performed at 20 to 110 degrees. In order to form sufficient cross-linking, 60 ° to 100 ° is preferable, and 80 ° to 100 ° is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is also preferably set to an optimum value for the cross-linking agent to be used. When glutaraldehyde is used, the pH is 4.5 to 5.5, and 4.8 to 5.2 is particularly preferable.

The alignment film can be obtained by cross-linking the polymer layer and then rubbing the surface if necessary.
For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing using a cloth in which fibers having uniform length and thickness are flocked on average.

<Support>
The optically anisotropic film may be formed on a support. The support is preferably transparent, and specifically, the light transmittance is preferably 80% or more.
Examples of the polymer film as the support include cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate films. A cellulose ester film is preferred, an acetyl cellulose film is more preferred, and a triacetyl cellulose film is most preferred. The polymer film is preferably formed by a solvent cast method. The thickness of the transparent support is preferably 20 to 500 μm, and more preferably 40 to 200 μm. In order to improve adhesion between the transparent support and the layer (adhesive layer, vertical alignment film or retardation layer) provided thereon, surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet light (UV) ) Treatment, flame treatment, saponification treatment). An adhesive layer (undercoat layer) may be provided on the transparent support. Moreover, the average particle diameter is 10 to 100 nm in order to give the transparent support or the long transparent support a slip property in the transport process or to prevent the back surface and the surface from sticking after winding. It is preferable to use what formed the polymer layer which mixed the inorganic particle of about 5%-40% by solid content mass ratio on the one side of the support body by application | coating or co-casting with a support body.

  The optically anisotropic film formed by curing the liquid crystal composition of the present invention can be used for various applications. In particular, it is useful as an optical compensation film for liquid crystal display devices.

Hereinafter, the present invention will be described in more detail based on examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the following examples.
[Example 1]
100 parts by mass of a liquid crystal compound (78) having the following structure, and Chiba IRGACURE-819 (manufactured by Ciba Specialty Chemicals Co., Ltd .: absorbance of methanol solution at a wavelength of 405 nm: 899 × 10 ² ml / g · cm) as a polymerization initiator 2 parts by mass and 0.3 part by mass of additive (A) having the following structure were dissolved in 400 parts by mass of 1,1,2-trichloroethane to prepare a solution. This solution was spin-coated on a rubbing-treated glass substrate, dried at 120 ° C. for 1 minute, cooled to 90 ° C., and irradiated with a high-pressure mercury lamp. The obtained sample was a uniform retardation film having a slow axis in the rubbing direction. The surface of the sample was rubbed with a Kimwipe, but it was not scratched and there was no substitute for it.

[Example 2]
In Example 1, the amount of the polymerization initiator was changed to 0.3, 0.5, 1, 4, and 5 parts by mass with respect to 100 parts by mass of the liquid crystal compound, respectively. Was prepared and applied to a rubbing-treated glass substrate to prepare a sample.
The sample in which the addition amount of the polymerization initiator was 0.3 parts by mass was soft, and the film surface was damaged when rubbed with Kimwipe.
The sample in which the addition amount of the polymerization initiator was 0.5 to 4 parts by mass was sufficiently hard, and the surface of the sample was rubbed with Kimwipe but was not scratched at all. There was no change from before the rub.
When the addition amount of the polymerization initiator was 5 parts by mass, the sample was isotropic at 90 ° C., and thus the composition was irradiated with a high pressure mercury lamp at 60 ° C. at which liquid crystallinity was exhibited. This sample was soft and scratched on the membrane surface when rubbed with Kimwipe.

[Comparative Example 1]
In Example 1, instead of Chiba IRGACURE-819 (Ciba Specialty Chemicals Co., Ltd.), Chiba IRGACURE-907 (Ciba Specialty Chemicals Co., Ltd.) was used instead of Chiba IRGACURE-819 (Ciba Specialty Chemicals Co., Ltd.). The sample was prepared in the same manner as in Example 1.
The obtained sample was a uniform retardation film having a slow axis in the rubbing direction. This sample was soft and rubbed with Kimwipe was full of scratches.

[Example 3]
A sample was prepared in the same manner as in Example 1 except that the polymerization initiator was changed to the following liquid crystal compound (a compound described in JP-A-2005-208416, which is a liquid crystal compound having birefringence and reverse wavelength dispersion). As in Example 1, this sample was a sufficiently hard film, and the sample surface was rubbed with Kimwipe but not scratched.

[Comparative Example 2]
When the polymerization initiator was IRGACURE-907 (manufactured by Ciba Specialty Chemicals Co., Ltd .: the absorbance of the methanol solution at a wavelength of 405 nm was 10 ml / g · cm or less), the curing was insufficient, and the resulting film was It was soft.

Claims (4)

Contains at least a liquid crystal compound having a polymerizable group and birefringence having a reverse wavelength dispersion in the visible light region, and a polymerization initiator having a light absorption coefficient of 100 (ml / g · cm) or more in methanol at a wavelength of 405 nm A liquid crystal composition characterized by comprising: 2. The liquid crystal composition according to claim 1, wherein the polymerization initiator is contained in an amount of 0.5 to 4 mass% with respect to the liquid crystal compound. The liquid crystal composition according to claim 1 or 2, wherein the liquid crystal compound is a compound represented by the following general formula (1):

In the formula, A ¹ and A ² each independently represent a group selected from the group consisting of —O—, —NR— (R represents a hydrogen atom or a substituent), —S—, and —CO—; Z Represents one or two atoms selected from the group consisting of a carbon atom and a non-metallic atom of Groups 14 to 16, and together with C—C═C—C or C═C—C═C described in the formula Forming a 5- or 6-membered ring; R ¹ , R ² and R ³ each independently represents a substituent; m is an integer from 0 to 4; L ¹ and L ² are each independently a single bond or two X represents a non-metal atom of Groups 14 to 16 (provided that a hydrogen atom or a substituent R ⁴ may be bonded to X); provided that R, R ¹ , R ² , R ³ and R ⁴ are substituents having a polymerizable group. An optically anisotropic material obtained by curing the liquid crystal composition according to claim 1.