JP6626896B2 - Polymerizable liquid crystal composition, retardation film, polarizing plate, liquid crystal display device, and organic electroluminescent device - Google Patents

Description

  The present invention relates to a polymerizable liquid crystal composition, a retardation film, a polarizing plate, a liquid crystal display, and an organic electroluminescent device.

2. Description of the Related Art Conventionally, a polarizing plate having a retardation film and a polarizer has been used for a liquid crystal display device, an organic electroluminescent device, and the like for the purpose of optical compensation and antireflection.
In recent years, there has been developed a polarizing plate (so-called broadband polarizing plate) capable of giving the same effect to white light, which is a composite wave in which light beams in the visible light region are mixed, corresponding to light beams of all wavelengths. In particular, the thickness of the retardation film included in the polarizing plate is also required to be reduced in order to reduce the thickness of a device to which the polarizing plate is applied.
In response to the above requirements, for example, Patent Documents 1 and 2 propose the use of a polymerizable liquid crystal compound having reverse wavelength dispersion as a polymerizable compound used for forming a retardation film.

International Publication No. WO 2014/010325 JP 2011-207765 A

  However, a polarizing plate having a retardation film formed using a polymerizable liquid crystal (polymerizable compound) having reverse wavelength dispersion described in Patent Documents 1 and 2 is manufactured, and the polarizing plate is subjected to high temperature and high humidity. Exposure for a long time, the fluctuation value of the in-plane retardation (Re) may become too large (that is, decrease in wet heat durability), and desired optical performance may not be obtained. It became clear.

  Therefore, the present invention relates to a polymerizable liquid crystal composition capable of producing a retardation film having excellent wet heat durability, and a retardation film, a polarizing plate, a liquid crystal display device, and an organic electroluminescent device obtained by using the same.

The present inventors have conducted intensive studies on the above problems, and as a result, have found that by using a polymerizable liquid crystal composition containing a predetermined organic oxidizing agent, a retardation film having excellent wet heat durability can be produced. Was.
That is, the inventor has found that the above-described problem can be solved by the following configuration.

[1]
A polymerizable liquid crystal composition containing an organic oxidizing agent represented by the following general formula (A) and a polymerizable liquid crystal compound having reverse wavelength dispersion.
[2]
The polymerizable liquid crystal composition according to the above [1], wherein the polymerizable liquid crystal compound is a liquid crystal compound represented by the following general formula (II).
[3]
The polymerizable liquid crystal composition according to the above [1] or [2], wherein the reduction potential of the organic oxidant is more noble than 0 volt.
[4]
A retardation film formed using the polymerizable liquid crystal composition according to any one of the above [1] to [3],
In-plane retardation value Re (450) measured at a wavelength of 450 nm, in-plane retardation value Re (550) measured at a wavelength of 550 nm, and In-plane retardation value Re measured at a wavelength of 650 nm. (650) and Re (450) ≦ Re (550) ≦ Re (650).
[5]
The retardation film according to the above [4], wherein the retardation film is a positive A plate.
[6]
The retardation film according to the above [5], wherein the positive A plate is a λ / 4 plate.
[7]
A polarizing plate comprising: the retardation film according to any one of the above [4] to [6]; and a polarizer.
[8]
A liquid crystal display device comprising the polarizing plate according to the above [7].
[9]
An organic electroluminescent device comprising the polarizing plate according to [7].

  As shown below, according to the present invention, a polymerizable liquid crystal composition capable of producing a retardation film having excellent wet heat durability, a retardation film obtained using the same, a polarizing plate, a liquid crystal display device, and an organic electroluminescent device An apparatus can be provided.

Hereinafter, the polymerizable liquid crystal composition, retardation film, polarizing plate, liquid crystal display device, and organic electroluminescent device of the present invention will be described.
In this specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit.
In addition, “orthogonal” and “parallel” with respect to an angle mean a range of an exact angle ± 10 °, and “same” and “different” with respect to an angle indicate whether the difference is less than 5 ° Can be determined based on
In this specification, “visible light” refers to 380 to 780 nm. In this specification, the measurement wavelength is 550 nm unless otherwise specified.
Next, terms used in the present specification will be described.

<Slow axis>
In this specification, the term “slow axis” means a direction in which the refractive index becomes maximum in a plane. In addition, the slow axis of the retardation film means the slow axis of the entire retardation film.

<Tilt angle>
In the present specification, the “tilt angle” (also referred to as a tilt angle) means an angle formed by an inclined liquid crystal compound with a layer plane, and the direction of the maximum refractive index in the refractive index ellipsoid of the liquid crystal compound is defined as the layer plane. It means the largest angle among the angles made. Therefore, in the case of a rod-shaped liquid crystal compound having a positive optical anisotropy, the tilt angle means the angle between the major axis direction of the rod-shaped liquid crystal compound, that is, the director direction and the layer plane. Further, in the present invention, the “average tilt angle” means an average value of the scribe angle from the tilt angle at the upper interface to the lower interface of the retardation film.

<Re (λ), Rth (λ)>
In the present specification, “Re (λ)” and “Rth (λ)” represent an in-plane retardation at a wavelength λ and a retardation in a thickness direction, respectively.
Re (λ) is measured by using KOBRA 21ADH or KOBRA WR (both manufactured by Oji Scientific Instruments) with light having a wavelength of λ nm incident in the normal direction of the film. In selecting the measurement wavelength λ nm, the measurement can be performed by manually exchanging the wavelength selection filter or converting the measured value by a program or the like.

Here, 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 defined as Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or KOBRA WR) as the tilt axis (rotation axis) (when there is no slow axis, the in-plane (Any direction is defined as the axis of rotation) With respect to the normal direction of the film, light of wavelength λ nm is incident from the inclined direction in 10-degree steps from the normal direction to 50 degrees on one side in each direction, and a total of six points are measured. It is calculated in KOBRA 21ADH or KOBRA WR based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above, in the case of a film having a direction in which the retardation value becomes zero at a certain inclination angle with the in-plane slow axis as a rotation axis from the normal direction, retardation at an inclination angle larger than the inclination angle The value is calculated in KOBRA 21ADH or KOBRA WR after changing its sign to negative.
In addition, the retardation value was measured from any two inclined directions using the slow axis as a tilt axis (rotation axis) (when there is no slow axis, an arbitrary direction in the film plane is used as the rotation axis). Rth can also be calculated from the following formulas (1) and (2) based on the value, the assumed value of the average refractive index, and the input film thickness value.

  In the formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from a normal direction. In addition, 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 thickness of the film.

When the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optical axis (OPTIC AXIS), Rth (λ) is calculated by the following method.
Rth (λ) is obtained by calculating Re (λ) by using an in-plane slow axis (determined by KOBRA 21ADH or KOBRA WR) as an inclination axis (rotation axis) from −50 degrees to +50 degrees with respect to the film normal direction. The light having a wavelength of λ nm is incident from each of the inclined directions in 10-degree steps, and 11 points are measured. Based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value, KOBRA 21ADH is measured. Alternatively, it is calculated by KOBRA WR.

  In the above measurement, as the assumed value of the average refractive index, a value from a catalog of various optical films or a polymer handbook (John Wiley & Sons, Inc.) can be used. If the value of the average refractive index is not known, it can be measured with an Abbe refractometer. Examples of average refractive index values of main optical films are as follows: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), 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 KOBRA WR. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

[Polymerizable liquid crystal composition]
The polymerizable liquid crystal composition of the present invention comprises an organic oxidant represented by the following general formula (A) (hereinafter, also simply referred to as “specific organic oxidant”) and a polymerizable liquid crystal compound having reverse wavelength dispersion ( Hereinafter, simply referred to as “specific liquid crystal compound”).
According to the polymerizable liquid crystal composition of the present invention, a retardation film having excellent wet heat durability can be produced. Although the details of this reason have not been clarified yet, it is presumed that the reason is as follows.

A polymerizable liquid crystal compound is easily susceptible to hydrolysis by water, and this problem tends to be more pronounced when a polymerizable liquid crystal compound (specific liquid crystal compound) having reverse wavelength dispersion among polymerizable liquid crystal compounds is used.
Specifically, when the retardation film produced using the specific liquid crystal compound is exposed to high temperature and high humidity conditions, after a certain induction period, the specific liquid crystal compound contained in the retardation film is hydrolyzed. It has been found that decomposition occurs rapidly, and the fluctuation of the in-plane retardation value increases. The reason is presumed to be due to the following phenomenon.
That is, as one method for making the polymerizable liquid crystal compound reverse wavelength dispersive, there is a case where the polymerizable liquid crystal compound has an electron-withdrawing property. Becomes larger and more vulnerable to nucleophilic attack. As a result, a decomposition product derived from the decomposed polymerizable liquid crystal compound (for example, a divalent aromatic ring derived from Ar in the case of using general formula (II) described later) serves as a catalyst, and unreacted It is assumed that the hydrolysis of the polymerizable liquid crystal compound is further promoted.

  As a result of further studies by the inventors on such a problem, they found that the use of a specific organic oxidizing agent can improve the wet heat durability of the retardation film. This is presumed to be due to the fact that the specific organic oxidizing agent oxidatively decomposes the decomposition product derived from the specific liquid crystal compound by an electron transfer reaction, thereby suppressing the above-mentioned catalytic reaction of the decomposition product. .

<Organic oxidant represented by formula (A) (specific organic oxidant)>
The polymerizable liquid crystal composition of the present invention contains an organic oxidant (specific organic oxidant) represented by the following general formula (A).

In the general formula (A), X ¹ and X ² each independently represent an oxygen atom, a sulfur atom, ＝ NR ¹ group, or ＝ CR ² R ³ group. If each of X ¹ and X ² there are a plurality each of the plurality of X ¹ and a plurality of X ² may be the same or different from each other.
Among the above, X ¹ and X ² are selected from the group consisting of oxygen, which can increase the reduction potential (can increase the oxidizing power) from the viewpoint that the effect of oxidatively decomposing and removing the decomposition products derived from the specific liquid crystal compound is further improved. An atom or = CR ² R ³ group is preferred, and a = CR ² R ³ group is more preferred.

  m and n each independently represent an integer of 0 to 3, preferably an integer of 1 to 3, more preferably 1 or 2, and still more preferably 1. However, the sum of m and n is 2 or more, preferably 2 to 6, more preferably 2 to 4, and even more preferably 2.

R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent. When a plurality of each of R ¹ , R ² and R ³ are present, the plurality of R ¹ , the plurality of R ² and the plurality of R ³ may be the same or different from each other.
L ¹ and L ² each independently represent a divalent linking group.

The substituent represented by R ¹ , R ² and R ³ is a halogen atom or a substituent bonded by a carbon atom, an oxygen atom, a nitrogen atom or a sulfur atom, and specifically, an alkyl group, an alkenyl group , Aralkyl, aryl, heterocyclic, halogen, cyano, nitro, mercapto, hydroxy, alkoxy, aryloxy, alkylthio, arylthio, acyloxy, amino, alkylamino, carboxylic Amido group, sulfonamide group, sulfamoylamino group, oxycarbonylamino group, oxysulfonylamino group, ureido group, thioureido group, acyl group, oxycarbonyl group, carbamoyl group, sulfonyl group, sulfinyl group, sulfamoyl group, carboxyl group (Including salts) and sulfo groups (salts ). These may be further substituted with these substituents. Among them, a reduction potential can be increased (oxidation power can be increased) from the viewpoint that the effect of oxidatively decomposing and removing decomposition products derived from the specific liquid crystal compound is further improved (an oxidizing power can be increased), a cyano group, an acyl group, or It is preferably an oxycarbonyl group, more preferably a cyano group or an oxycarbonyl group, even more preferably a cyano group.

Examples of the substituent represented by R ¹ , R ² and R ³ are shown in more detail. The alkyl group is preferably a linear, branched, or cyclic alkyl group having 1 to 18 carbon atoms (more preferably, 6 to 18 carbon atoms), for example, methyl, ethyl, propyl, isopropyl, t-butyl, Cyclopentyl, cyclohexyl, 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, 3-methoxypropyl, 2-aminoethyl, acetamidomethyl, 2-acetamidoethyl, carboxymethyl, 2-carboxyethyl, 2-sulfoethyl, ureido Examples thereof include methyl, 2-ureidoethyl, carbamoylmethyl, 2-carbamoylethyl, 3-carbamoylpropyl, pentyl, hexyl, octyl, decyl, undecyl, dodecyl, hexadecyl, and octadecyl.
The alkenyl group is preferably a linear, branched or cyclic alkenyl group having 2 to 18 carbon atoms (more preferably 6 to 18 carbon atoms), for example, vinyl, allyl, 1-propenyl, 2-pentenyl, Examples thereof include 1,3-butadienyl, 2-octenyl, and 3-dodecenyl.

The aralkyl group is preferably an aralkyl group having 7 to 10 carbon atoms, such as benzyl.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms, and examples include phenyl, naphthyl, p-dibutylaminophenyl, and p-methoxyphenyl.
The heterocyclic group preferably includes a 5- to 6-membered saturated or unsaturated heterocyclic group composed of a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom. The number of heteroatoms constituting the ring and the type of element may be one or more, and for example, furyl, benzofuryl, pyranyl, pyrrolyl, imidazolyl, isoxazolyl, pyrazolyl, benzotriazolyl, pyridyl, pyrimidyl, pyridazinyl, Thienyl, indolyl, quinolyl, phthalazinyl, quinoxalinyl, pyrrolidinyl, pyrrolinyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, piperidyl, piperazinyl, indolinyl, and morpholinyl.
Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.
The alkoxy group is preferably an alkoxy group having 1 to 18 carbon atoms (more preferably 6 to 18 carbon atoms), for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, 2-methoxyethoxy, 2-methanesulfonyl Examples include ethoxy, pentyloxy, hexyloxy, octyloxy, undecyloxy, dodecyloxy, hexadecyloxy, and octadecyloxy.
The aryloxy group preferably includes an aryloxy group having 6 to 10 carbon atoms, and examples thereof include phenoxy and p-methoxyphenoxy.
The alkylthio group preferably includes an alkylthio group having 1 to 18 carbon atoms (more preferably, 6 to 18 carbon atoms), such as methylthio, ethylthio, octylthio, undecylthio, dodecylthio, hexadecylthio, and octadecylthio. Can be
The arylthio group is preferably an arylthio group having 6 to 10 carbon atoms, and examples thereof include phenylthio and 4-methoxyphenylthio.
The acyloxy group is preferably an acyloxy group having 1 to 18 carbon atoms (more preferably 6 to 18 carbon atoms), for example, acetoxy, propanoyloxy, pentanoyloxy, octanoyloxy, dodecanoyloxy, and Octadecanoyloxy and the like can be mentioned.

The alkylamino group is preferably an alkylamino group having 1 to 18 carbon atoms (more preferably an alkylamino group having 6 to 18 carbon atoms), for example, methylamino, dimethylamino, diethylamino, dibutylamino, octylamino, dioctylamino, and , Undecylamino and the like. The carbonamido group is preferably a carbonamido group having 1 to 18 carbon atoms (more preferably 6 to 18 carbon atoms), for example, acetamido, acetylmethylamino, acetyloctylamino, acetyldecylamino, acetylundecylamino Acetyloctadecylamino, propanoylamino, pentanoylamino, octanoylamino, octanoylmethylamino, dodecanoylamino, dodecanoylmethylamino, and octadecanoylamino.
The sulfonamide group is preferably a sulfonamide group having 1 to 18 carbon atoms (more preferably 6 to 18 carbon atoms), such as methanesulfonamide, ethanesulfonamide, propylsulfonamide, and 2-methoxyethylsulfonamide. , 3-aminopropylsulfonamide, 2-acetamidoethylsulfonamide, octylsulfonamide, and undecylsulfonamide.
The oxycarbonylamino group is preferably an oxycarbonylamino group having 1 to 18 carbon atoms (more preferably 8 to 18 carbon atoms), such as methoxycarbonylamino, ethoxycarbonylamino, octyloxycarbonylamino, and unoxycarbonylamino. Decyloxycarbonylamino and the like.
The oxysulfonylamino group is preferably an oxysulfonylamino group having 1 to 18 carbon atoms (more preferably 8 to 18 carbon atoms), for example, methoxysulfonylamino, ethoxysulfonylamino, octyloxysulfonylamino, and Decyloxysulfonylamino and the like.
The sulfamoylamino group is preferably a sulfamoylamino group having 0 to 18 carbon atoms (more preferably 8 to 18 carbon atoms), for example, methylsulfamoylamino, dimethylsulfamoylamino, ethylsulfamoyl Examples include amino, propylsulfamoylamino, octylsulfamoylamino, and undecylsulfamoylamino.
The ureido group is preferably a ureido group having 1 to 18 carbon atoms (more preferably 8 to 18 carbon atoms), for example, ureide, methyl ureide, N, N-dimethyl ureide, octyl ureide, and undecyl ureide And the like.
The thioureido group is preferably a thioureido group having 1 to 18 carbon atoms (more preferably 8 to 18 carbon atoms), for example, thioureido, methylthioureido, N, N-dimethylthioureido, octylthioureido, and unthioureido. Decylthioureido and the like.
The acyl group is preferably an acyl group having 1 to 18 carbon atoms (more preferably 8 to 18 carbon atoms), such as acetyl, benzoyl, octanoyl, decanoyl, undecanoyl and octadecanoyl.
The oxycarbonyl group is preferably an oxycarbonyl group having 1 to 18 carbon atoms (more preferably an oxycarbonyl group having 8 to 18 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, octyloxycarbonyl, and undecyloxycarbonyl). Can be
The carbamoyl group is preferably a carbamoyl group having 1 to 18 carbon atoms (more preferably 8 to 18 carbon atoms), for example, carbamoyl, N, N-dimethylcarbamoyl, N-ethylcarbamoyl, N-octylcarbamoyl, , N-dioctylcarbamoyl and N-undecylcarbamoyl.
The sulfonyl group is preferably a sulfonyl group having 1 to 18 carbon atoms (more preferably 8 to 18 carbon atoms). Examples thereof include methanesulfonyl, ethanesulfonyl, 2-chloroethanesulfonyl, octanesulfonyl, and undecanesulfonyl. No.
The sulfinyl group is preferably a sulfinyl group having 1 to 18 carbon atoms (more preferably 8 to 18 carbon atoms), and examples thereof include methanesulfinyl, ethanesulfinyl, and octanesulfinyl.
The sulfamoyl group is preferably a sulfamoyl group having 0 to 18 carbon atoms (more preferably a sulfamoyl group having 8 to 18 carbon atoms, for example, sulfamoyl, dimethylsulfamoyl, ethylsulfamoyl, octylsulfamoyl, dioctylsulfamoyl). , And undecylsulfamoyl.

L ¹ and L ² each independently represent a divalent linking group.
Here, the divalent linking group is composed of a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, and forms a 4- to 8-membered ring together with the carbon atom substituted by X ¹ and X ² . Specific examples of L ¹ and L ² include -C (R ⁴ ) (R ⁵ )-, -C (R ⁶ ) =, -N (R ⁷ )-, -N =, -O-, and -S -Are combined. Here, R ⁴ , R ⁵ , R ⁶ and R ⁷ represent a hydrogen atom or a substituent, and the details thereof are the same as those described for R ¹ , R ² and R ³ .
The 4- to 8-membered ring may form a saturated or unsaturated condensed ring, and examples of the condensed ring include a cycloalkyl ring, an aryl ring and a hetero ring. , R ¹ , R ² and R ³ have the same meanings.
Examples of the 4- to 8-membered ring include cyclobutanedione, cyclobutenedione, and benzocyclobutenequinone as examples of 4-membered rings, and cyclopentanedione, cyclopentenedione, and cyclopentane as examples of 5-membered rings. Trione, cyclopentenetrione, indandione, indantrione, tetrahydrofurandion, tetrahydrofurantrione, tetrahydropyrroledione, tetrahydropyrroletrione, tetrahydrothiophenedione, tetrahydrothiophenetrione, and the like, as examples of a six-membered ring, benzoquinone, quinomethane, quinodimethane, Quinone imine, quinone diimine, thiobenzoquinone, dithiobenzoquinone, naphthoquinone, anthraquinone, dihydrochromemention, dihydropyridinedione Dihydropyrazinedione, dihydropyrimidinedione, dihydropyridazinedione, dihydrophthalazinedione, dihydroisoquinolinedione, tetrahydroquinolinetrione, and the like, as examples of a 7-membered ring, cycloheptanedione, cycloheptanetrione, azacycloheptanetrione, Zacycloheptanetrione, oxocycloheptanetrione, dioxocycloheptanetrione, oxoazacycloheptanetrione, and the like, as examples of an 8-membered ring, cyclooctanedione, cyclooctanetrione, azacyclooctanetrione, diazacyclooctane Trione, oxocyclooctanetrione, dioxocyclooctanetrione, oxoazacyclooctanetrione, cyclooctenedione, cyclooctadiene On, and the like can be given dibenzo cyclooctene dione. The ring formed by L ¹ and L ^{2 in combination} with the carbon atom substituted by X ¹ and X ² is preferably a 6-membered ring.

  Among the compounds represented by the general formula (A), a compound represented by the following general formula (AI) is preferable.

In Formula (AI), R ¹⁰ , R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom or a substituent. The definition of the substituent is as described above.
When R ¹⁰ and R ¹¹ , or R ¹² and R ¹³ simultaneously serve as a substituent, they may be linked to each other to form an unsaturated condensed ring. The unsaturated condensed ring may have a substituent, and examples of the substituent include the same as those described for R ^{1 to} R ³ . X ¹¹ and X ²² may be the same or different and have the same meanings as X ¹ and X ² , respectively, and preferred embodiments thereof are also the same.

X ¹¹ and X ²² in the general formula (AI) are preferably an oxygen atom or a ＝ C (R ¹⁴ ) (R ¹⁵ ) group, and at the same time, an oxygen atom or a ＣC (R ¹⁴ ) (R ¹⁵ ) group. More preferably, Here, R ¹⁴ and R ¹⁵ each independently represent a halogen atom, a cyano group, an acyl group, an oxycarbonyl group or a sulfonyl group.
When X ¹¹ and X ²² in the general formula (AI) are simultaneously oxygen atoms, it is more preferable that at least two or more of R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are electron-withdrawing groups, Here, the electron-withdrawing group refers to a substituent having a positive Hammett σp value, specifically, a halogen atom, a cyano group, a nitro group, an acyl group, an oxycarbonyl group, a carbamoyl group, a sulfonyl group, and And a sulfinyl group.
As a particularly preferred combination when X ¹¹ and X ²² are simultaneously an oxygen atom, R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are preferably a hydrogen atom, an alkyl group, a halogen atom, a cyano group, a nitro group, an alkoxy group, an alkylthio group. Group, amino group, alkylamino group, carbonamido group, sulfonamido group, sulfamoylamino group, oxycarbonylamino group, oxysulfonylamino group, ureido group, thioureido group, acyl group, oxycarbonyl group, carbamoyl group, sulfonyl Group, a sulfinyl group, or a sulfamoyl group, at least two of which are electron-withdrawing groups, and the most preferable combination is a group in which R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are a hydrogen atom, a carbon atom number of 8 to 18 alkyl groups, halogen atoms, cyano groups, carbon number C18 to C18 alkylthio group, C8 to C18 carbonamido group, C8 to C18 sulfonamide group, C8 to C18 ureido group, C8 to C18 An acyl group, an oxycarbonyl group having 8 to 18 carbon atoms, a carbamoyl group having 8 to 18 carbon atoms, a sulfonyl group having 8 to 18 carbon atoms, or a sulfinyl group having 8 to 18 carbon atoms, of which at least two or more are A halogen atom, a cyano group, a sulfonyl group or a sulfinyl group.

  Among the compounds represented by the general formula (AI), a compound represented by the following general formula (A-II) is preferable.

In the general formula (A-II), R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ may be the same or different, and have the same meaning as that described for R ^{10 to} R ¹³ .

  Among the compounds represented by the general formula (A-II), a compound represented by the following general formula (A-III) or (A-IV) is preferable.

In formula ^{(A-III), R 31} is a halogen atom, a cyano group, an alkoxy group, an alkylthio group, a carbonamido group, a sulfonamido group, a ureido group, an acyl group, or an oxycarbonyl ^{group, R 031} is R It may be the same as those described in ¹ to R ^3. m ⁴ represents an integer of 1 to 4, and when m ⁴ or 4-m ⁴ represents an integer of 2 or more, a plurality of R ³¹ and a plurality of R ⁰³¹ may be the same or different from each other.

Preferred combinations of R ³¹ and R ^{031 in} formula (A-III) will be described below.
R ³¹ is a halogen atom, a cyano group, an alkoxy group having 8 to 18 carbon atoms, an acyl group having 8 to 18 carbon atoms or an oxycarbonyl group having 8 to 18 carbon atoms, and R ⁰³¹ is a hydrogen atom, 8 carbon atoms. A combination in which “4-m ⁴ ” representing the number of the alkyl group to R 18 or the number of R ⁰³¹ is 0 (that is, not substituted with R ⁰³¹ ) is preferable.
More preferred is a combination in which R ³¹ is an alkoxy group having 8 to 18 carbon atoms or a halogen atom, and R ⁰³¹ is a hydrogen atom or “4-m ⁴ ” representing the number of R ⁰³¹ is 0. .

In the general formula (A-IV), R ³² represents a hydrogen atom or a substituent. Here, examples of the substituent include the same as those described for R ^{1 to} R ³ . m ⁵ represents an integer of 0 to 6, when m ⁵ represents an integer of 2 or more, plural R ³² may be the same or different from each other.

R ³² in the general formula (A-IV) is preferably a hydrogen atom, an alkyl group, a halogen atom, a cyano group, an alkoxy group, an alkylthio group, a carbonamide group, a sulfonamide group, a ureido group, or an acyl group. More preferably, a hydrogen atom, an alkyl group having 8 to 18 carbon atoms, a halogen atom, a cyano group, an alkoxy group having 8 to 18 carbon atoms, an alkylthio group having 8 to 18 carbon atoms, and a carbonamide group having 8 to 18 carbon atoms A sulfonamide group having 8 to 18 carbon atoms, a ureido group having 8 to 18 carbon atoms, or an acyl group having 8 to 18 carbon atoms, more preferably a hydrogen atom, an alkyl group having 8 to 18 carbon atoms, and fluorine. An atom, a chlorine atom, a bromine atom, a cyano group, or an alkoxy group having 8 to 18 carbon atoms, and particularly preferably a hydrogen atom.

  Examples of specific compounds of the organic oxidant of the present invention are shown below, but the organic oxidant of the present invention is not limited to these.

  The specific organic oxidizing agent may be used alone or in combination of two or more.

The specific organic oxidizing agent is preferably an oxidizing agent having a high oxidizing power (that is, a reduction potential is noble) from the viewpoint that the function of oxidatively decomposing and removing a decomposition product derived from the specific liquid crystal compound is further improved.
Specifically, the reduction potential (Ered) of the specific organic oxidant is preferably noble than 0 volt (more than 0 volt), more preferably noble than 0.1 volt (more than 0.1 volt). More preferably, it is more noble than 0.3 volts (more than 0.3 volts), and particularly preferably noble than 0.5 volts (more than 0.5 volts). By being nobler than 0 volt, the above function is further exhibited.
The upper limit of the reduction potential (Ered) of the organic oxidant is preferably lower than 2 volts (less than 2 volts), more preferably lower than 1 volt (less than 1 volt). By being lower than 1 volt, there is an advantage that the specific organic oxidant can be prevented from decomposing the specific liquid crystal compound itself.
Here, the value of the reduction potential Ered means the potential at which the organic oxidant is reduced by the injection of electrons at the cathode in voltammetry, and the value of Ered can be accurately measured by this voltammetry. That is, a voltammogram of an organic oxidizing agent of 1 × 10 ⁻³ M is measured in acetonitrile containing 0.1 M of tetra-n-ethylammonium perchlorate as a supporting electrolyte, and the half-wave potential obtained from the voltammogram can be obtained. it can. More specifically, platinum is used for the working electrode and a saturated calomel electrode (SCE) is used for the reference electrode, and the measurement is performed at 25 ° C.

  The content of the specific organic oxidizing agent is preferably 0.1 to 25 parts by mass, and more preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the specific liquid crystal compound contained in the polymerizable liquid crystal composition. Is more preferably 1 to 20 parts by mass, still more preferably 1 to 10 parts by mass, particularly preferably 1 to 8 parts by mass, and 1 to 5 parts by mass. Most preferred. When the content of the specific organic oxidizing agent is 0.1 parts by mass or more, the effect of oxidatively decomposing a decomposition product derived from the specific liquid crystal compound is further improved. In particular, when the content of the specific organic oxidant is 20 parts by mass or less, it is possible to prevent the specific organic oxidant from decomposing the specific liquid crystal compound itself.

<Polymerizable liquid crystal compound with reverse wavelength dispersion (specific liquid crystal compound)>
The polymerizable liquid crystal composition of the present invention contains a polymerizable liquid crystal compound having reverse wavelength dispersion (specific liquid crystal compound).
As used herein, the term “polymerizable liquid crystal compound having“ reverse wavelength dispersion ”” refers to an in-plane retardation (Re) value at a specific wavelength (visible light range) of a retardation film produced using the compound. When the measurement is performed, the value of Re becomes equal or higher as the measurement wavelength increases. As described later, the value of Re (450) ≦ Re (550) ≦ Re (650) is satisfied.

In addition, a polymerizable liquid crystal compound in this specification refers to a liquid crystal compound having a polymerizable group.
The type of the polymerizable group of the specific polymerizable liquid crystal compound of the present invention is not particularly limited, and examples thereof include an acryloyl group, a methacryloyl group, a vinyl group, a styryl group, and an allyl group.

Although the kind of the specific liquid crystal compound is not particularly limited, it can be classified into a rod type (rod liquid crystal compound) and a disk type (disk liquid crystal compound; discotic liquid crystal compound) according to its shape. Furthermore, there are a low molecular type and a high molecular type, respectively. A polymer generally refers to a polymer having a degree of polymerization of 100 or more (polymer physics / phase transition dynamics, Masao Doi, page 2, Iwanami Shoten, 1992). In the present invention, any liquid crystal compound can be used. Two or more rod-shaped liquid crystal compounds, two or more disc-shaped liquid crystal compounds, or a mixture of a rod-shaped liquid crystal compound and a disc-shaped liquid crystal compound may be used.
Among these, it is preferable to use a rod-shaped liquid crystal compound. This is because, by aligning the rod-shaped liquid crystal compound homogeneously (horizontally), there is an advantage that the formed retardation film can easily function as a positive A plate.

  The specific liquid crystal compound of the present invention is not particularly limited as long as it can form a film having reverse wavelength dispersion as described above. For example, it is represented by the general formula (I) described in JP-A-2008-297210. (Particularly, the compounds described in paragraphs [0034] to [0039]) and the compound represented by the general formula (1) described in JP-A-2010-84032 (particularly, paragraphs [0067] to [0067] [0073] and liquid crystal compounds represented by the following general formula (II) and the like can be used.

  The above-mentioned specific liquid crystal compound preferably contains a liquid crystal compound represented by the following general formula (II) from the viewpoint of more excellent reverse wavelength dispersion.

L ₁ -G ₁ -D ₁ -Ar-D ₂ -G ₂ -L ₂ (II)

In the general formula (II), D ₁ and D ₂ are each independently a single bond, —CO—O—, —C (＝ S) O—, —CR ¹ R ² —, —CR ¹ R ² —CR ^{3 R 4 -, - O-} CR 1 R 2 -, - CR 1 R 2 -O-CR 3 R 4 -, - CO-O-CR 1 R 2 -, - O-CO-CR 1 R 2 -, —CR ¹ R ² —O—CO—CR ³ R ⁴ —, —CR ¹ R ² —CO—O—CR ³ R ⁴ —, —NR ¹ —CR ² R ³ — or —CO—NR ¹ — .
R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms. When a plurality of each of R ¹ , R ² , R ³ and R ⁴ are present, a plurality of R ¹ , a plurality of R ² , a plurality of R ³ and a plurality of R ⁴ may be the same or different from each other. Good.
G ₁ and G ₂ each independently represent a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group is -O-, -S-, Alternatively, it may be substituted with -NH-.
L ₁ and L ₂ each independently represent a monovalent organic group, and at least one selected from the group consisting of L ₁ and L ₂ represents a monovalent group having a polymerizable group.
Ar represents a divalent aromatic ring group represented by the following formula (II-1), (II-2), (II-3) or (II-4).

In the general formulas (II-1) to (II-4), Q ₁ represents -CH- or -N-;
Q ₂ represents —S—, —O—, or —NR ¹¹ —,
R ¹¹ 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 or an aromatic heterocyclic group having 3 to 12 carbon atoms (where the aromatic hydrocarbon group and the aromatic heterocyclic group are substituents; May be included),
Z ₁ , Z ₂ and Z ₃ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a monovalent having 6 to 20 carbon atoms. It represents an aromatic hydrocarbon group, a halogen atom, a cyano group, a nitro ^group, a ^-NR 12 ^{R 13} or ^{-SR 12,}
Z ₁ and Z ₂ may combine with each other to form an aromatic ring or an aromatic heterocyclic ring, and R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,
A ₁ and A ₂ are each independently a group selected from the group consisting of —O—, —NR ²¹ —, —S— and —CO—, wherein R ²¹ represents a hydrogen atom or a substituent; Is a non-metallic atom of a Group 14 to Group 16 to which a hydrogen atom or a substituent may be bonded (preferably, = 0, = S, = NR ', and = C (R') R ' (Where R ′ represents a substituent)),
Ax represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring, and is preferably an aromatic hydrocarbon ring group; Heterocyclic group; alkyl group having 3 to 20 carbon atoms having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon ring and aromatic heterocyclic ring; group consisting of aromatic hydrocarbon ring and aromatic heterocyclic ring An alkenyl group having 3 to 20 carbon atoms having at least one aromatic ring selected from the group consisting of: an alkenyl group having 3 to 20 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. Alkenyl groups,
Ay is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or a carbon atom having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. Represents an organic group of Formulas 2 to 30, and the preferred embodiment of the organic group is the same as the preferred embodiment of the organic group of Ax,
The aromatic rings in Ax and Ay may each have a substituent, and Ax and Ay may combine 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.
As the substituent, a halogen atom, an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, a cyano group, an amino group, a nitro group, a nitroso group, a carboxy group, an alkylsulfinyl group having 1 to 6 carbon atoms, a carbon atom An alkylsulfonyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylsulfanyl group having 1 to 6 carbon atoms, an N-alkylamino group having 1 to 6 carbon atoms, An N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 6 carbon atoms, an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms, or a combination thereof And the like.

With respect to the definition and the preferred range of each substituent of the liquid crystal compound represented by the general formula (II), D ¹ , D ² , G ¹ , G ² , and D ³ relating to the compound (A) described in JP-A-2012-21068. The description about L ¹ , L ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , X ¹ , Y ¹ , Q ¹ , and Q ^{2 is} described as D ₁ , D ₂ , G ₁ , G ₂ , L ₁ , L ₁ , respectively. ₂ , R ¹ , R ² , R ³ , R ⁴ , Q ₂ , Y ₁ , Z ₁ , and Z ₂ can be referred to and represented by the general formula (I) described in JP-A-2008-107767. _a 1 for, _{a 2,} and _a 1 a description of X respectively, _{a 2,} and X can refer for, Ax of the compound represented by the general formula described in WO 2013/018526 (I), Ay, and with respect to ^{Q 1} serial The possible reference Ax, Ay, and the _{Q 3,} respectively. For Z ₃ can refer to the description for ^{Q 1} relates to compounds (A) described in JP-A-2012-21068.

In particular, the organic group represented by _{L 1} and _{L 2,} respectively, in _particular, is preferably a group represented by _{-D 3 -G 3 -Sp-P 3} .
D ₃ has the same meaning as D ₁ .
G ₃ represents a single bond, a divalent aromatic or heterocyclic group having 6 to 12 carbon atoms, or a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, and the alicyclic hydrocarbon group May be substituted with —O—, —S—, or —NR ⁷ —, wherein R ⁷ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Sp is a single _{bond, - (CH 2) n -} , - (CH 2) n -O -, - (CH 2 -O-) n -, - (CH 2 CH 2 -O-) m, -O- _{(CH 2) n -, -} O- (CH 2) n -O -, - O- (CH 2 -O-) n -, - O- (CH 2 CH 2 -O-) m, -C (= _{O) -O- (CH 2) n} -, - C (= O) -O- (CH 2) n -O -, - C (= O) -O- (CH 2 -O-) n -, - _{C (= O) -O- (CH} 2 CH 2 -O-) m, -C (= O) -N (R 8) - (CH 2) n -, - C (= O) -N (R 8 ^{_{) - (CH 2) n -O}} -, - C (= O) -N (R 8) - (CH 2 -O-) n -, - C (= O) -N (R 8) - (CH 2 CH _{2 -O-) m or,, - (CH 2) n} -O- (C = O) - (CH 2 It represents a represented by a spacer group _{- n -C (= O) -O-} (CH 2) n. Here, n represents an integer of 2 to 12, m represents an integer of 2 to 6, and R ⁸ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Further, the hydrogen atom of —CH ₂ — in each of the above groups may be substituted with a methyl group.
P ₃ represents a polymerizable group.

The polymerizable group is not particularly limited, but is preferably a polymerizable group capable of radical polymerization or cationic polymerization.
As the radical polymerizable group, a generally known radical polymerizable group can be used, and preferable examples thereof include an acryloyl group and a methacryloyl group. In this case, it is known that the polymerization rate of acryloyl groups is generally high, and acryloyl groups are preferable from the viewpoint of improving productivity.However, methacryloyl groups may be used in the same manner as the polymerizable groups of the high birefringence liquid crystal. Can be.
As the cationic polymerizable group, generally known cationic polymerizable can be used, and specifically, an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro ortho ester group, and And a vinyloxy group. Among them, an alicyclic ether group or a vinyloxy group is preferable, and an epoxy group, an oxetanyl group, or a vinyloxy group is particularly preferable.
Examples of particularly preferred polymerizable groups include the following.

  In the present specification, the “alkyl group” may be linear, branched, or cyclic, and includes, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, Isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, 1,1-dimethylpropyl group, n-hexyl group, isohexyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, And a cyclohexyl group.

  Preferred examples of the liquid crystal compound represented by the general formula (II) are shown below, but it should not be construed that the invention is limited thereto. The 1,4-cyclohexylene groups in the following formulas are all trans-1,4-cyclohexylene groups.

  In the above formula, “*” represents a bonding position.

  When the liquid crystal compound represented by the general formula (II) is used, the content of the liquid crystal compound represented by the general formula (II) in the specific liquid crystal compound is preferably from 60 to 100% by mass, and 70% by mass. The content is more preferably from 100 to 100% by mass, and even more preferably from 70 to 90% by mass. When the content is 70% by mass or more, excellent reverse wavelength dispersion is obtained.

<Polymerization initiator>
The polymerizable liquid crystal compound of the present invention preferably contains a polymerization initiator.
The polymerization initiator used is preferably a photopolymerization initiator capable of initiating a polymerization reaction by ultraviolet irradiation.
Examples of the photopolymerization initiator include α-carbonyl compounds (described in U.S. Pat. Nos. 2,367,661 and 2,367,670), acyloin ethers (described in U.S. Pat. No. 2,448,828), and α-hydrocarbon-substituted fragrances Group acyloin compounds (described in U.S. Pat. No. 2,722,512), polynuclear quinone compounds (described in U.S. Pat. Nos. 3,046,127 and 2,951,758), and a combination of triarylimidazole dimer and p-aminophenyl ketone (U.S. Pat. No. 3,549,367), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850), oxadiazole compounds (US Pat. No. 4,221,970), and acyl Phosphine oxide compounds JP-A-63-40799, JP-B-5-29234, JP-A-10-95788, and JP-A-10-29997).

  Specific examples of the photopolymerization initiator include Irgacure series (for example, Irgacure 651, Irgacure 754, Irgacure 184, Irgacure 2959, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure 819) available from BASF. , And Irgacure OXE-01), Darocure series (eg, Darocure TPO and Darocure 1173, etc.), Quantacure PDO, Ezacure commercially available from Lamberti. Series (for example, Ezacure TZM, Ezacure TZT, and Ezacure KTO46).

  When the polymerization initiator is contained, the content of the polymerization initiator is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the specific liquid crystal compound contained in the polymerizable liquid crystal composition of the present invention. More preferably, the amount is 1 to 10 parts by mass.

<Polymerizable compound>
The polymerizable liquid crystal composition of the present invention may contain a polymerizable compound other than the above specific liquid crystal compound.
Here, the polymerizable group of the polymerizable compound is not particularly limited, and examples thereof include a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Especially, it is preferable to have a (meth) acryloyl group.

  In the present invention, the polymerizable compound having 2 to 4 polymerizable groups is preferable, and the polymerizable compound having 2 polymerizable groups is preferable, for example, for the reason that the durability of the retardation film is improved. More preferred.

Examples of such a polymerizable compound include compounds represented by formulas (M1), (M2), or (M3) described in paragraphs [0030] to [0033] of JP-A-2014-077068. And more specifically, specific examples described in paragraphs [0046] to [0055] of the publication.
The polymerizable compound may be used alone or in combination of two or more.

  In the present invention, the content in the case of containing the polymerizable compound is not particularly limited, in the total 100 parts by weight of the specific liquid crystal compound and the polymerizable compound described above, preferably 1 to 40 parts by mass, More preferably, the amount is 5 to 30 parts by mass.

<Solvent>
The polymerizable liquid crystal composition of the present invention preferably contains an organic solvent from the viewpoint of workability for forming a retardation film and the like.
As the organic solvent, specifically, for example, ketones (for example, acetone, 2-butanone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone), ethers (for example, dioxane, tetrahydrofuran, and the like), Aliphatic hydrocarbons (eg, hexane, etc.), alicyclic hydrocarbons (eg, cyclohexane, etc.), aromatic hydrocarbons (eg, toluene, xylene, and trimethylbenzene, etc.), halogenated carbons (eg, , Dichloromethane, dichloroethane, dichlorobenzene, and chlorotoluene), esters (for example, methyl acetate, ethyl acetate, and butyl acetate), water, and alcohols (for example, ethanol, isopropanol, butanol, and cyclohexanol) Such) Cellosolves (eg, methyl cellosolve and ethyl cellosolve), cellosolve acetates, sulfoxides (eg, dimethyl sulfoxide), and amides (eg, dimethylformamide, dimethylacetamide, etc.), and the like, These may be used alone or in combination of two or more.

<Other ingredients>
The polymerizable liquid crystal composition of the present invention may contain other components other than the above, for example, a liquid crystal compound other than the above, a leveling agent, a surfactant, a tilt angle controlling agent, an alignment assistant, a plasticizer, And a crosslinking agent.

[Retardation film]
The retardation film of the present invention is formed using the above polymerizable liquid crystal composition. Specifically, the retardation film of the present invention preferably has an optically anisotropic layer formed using the polymerizable liquid crystal composition.
The retardation film of the present invention is preferably a film formed by fixing a specific liquid crystal compound contained in the polymerizable liquid crystal composition by polymerization, and in this case, after forming the film, the film no longer exhibits liquid crystallinity. No need.
In this specification, the retardation film can be used for various display devices, light emitting devices, and optical members such as various optical elements such as polarizing plates.

The thickness of the retardation film is preferably 100 μm or less, more preferably 40 μm or less, and even more preferably 20 μm or less, from the viewpoint of reducing the thickness of the member. Further, from the viewpoint of production suitability, the thickness is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. In the case where the retardation film has a plurality of layers, the thickness of the retardation film indicates the entire thickness including the layers.
When the retardation film has the optically anisotropic layer, the thickness of the optically anisotropic layer is preferably 1 to 5 μm, more preferably 1 to 4 μm, and more preferably 1 to 3 μm. Is more preferred.

<Support layer>
The retardation film may have a support layer for supporting the optically anisotropic layer. In this case, the retardation film includes a support layer and an optically anisotropic layer formed on one surface of the support layer.
Such a support layer is preferably transparent, and specifically, preferably has a light transmittance of 80% or more. Examples of such a support include a glass substrate and a polymer film.
Further, a mode in which a polarizer described later also serves as such a support layer may be employed. In this case, in the present invention, it means a polarizing plate including a retardation film and a polarizer.
In the present invention, the thickness of the support layer is not particularly limited, but is preferably from 5 to 80 μm, more preferably from 10 to 40 μm.

<Orientation film>
The retardation film of the present invention may include an alignment film (alignment layer) having a function of defining the alignment direction of the specific liquid crystal compound. Thereby, it becomes easy to use the retardation film as a positive A plate.
The alignment film is a film (layer) provided on one surface of the optically anisotropic layer, and in the case where the retardation film includes the support layer, the alignment layer is formed of the support layer and the optically anisotropic layer. Located between.

In order to form a positive A plate described below, which is one embodiment of a retardation film, a technique for bringing molecules of a liquid crystal compound into a desired alignment state is used. A technique for orienting in a desired direction is general.
As the alignment film, a rubbing treatment film of a layer containing an organic compound such as a polymer, an oblique deposition film of an inorganic compound, a film having microgrooves, or a film such as ω-tricosanoic acid, dioctadecylmethylammonium chloride or methyl stearylate A film obtained by accumulating an LB (Langmuir-Blodgett) film of an organic compound by a Langmuir-Blodgett method is exemplified. Further, an alignment film or the like that generates an alignment function by light irradiation may be used.
As the alignment film, a film formed by rubbing the surface of a layer containing an organic compound such as a polymer (polymer layer) can be preferably used. The rubbing treatment is performed by rubbing the surface of the polymer layer several times with paper or cloth in a certain direction (preferably, the longitudinal direction of the support). Examples of the polymer used for forming the alignment film include polyimide, polyvinyl alcohol, modified polyvinyl alcohol described in paragraphs [0071] to [0095] of Japanese Patent No. 3907735, or described in JP-A-9-152509. It is preferable to use a polymer having a polymerizable group.
The thickness of the alignment film is not particularly limited as long as it can exert an alignment function, but is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm.

As a preferred embodiment, a so-called photo-alignment film (photo-alignment layer) in which a photo-alignable material is irradiated with polarized or non-polarized light to form an alignment layer is used. It is preferable that the photo-alignment film is provided with an alignment regulating force by a step of irradiating polarized light from a vertical direction or an oblique direction or a step of irradiating non-polarized light from an oblique direction.
By using the photo-alignment film, the specific liquid crystal compound can be horizontally aligned with excellent symmetry. Therefore, the positive A plate formed using the photo-alignment film is particularly useful for optical compensation in a liquid crystal display device that does not require a pre-tilt angle of a driving liquid crystal as in an IPS (In-Place-Switching) mode liquid crystal display device. It is.

  Examples of the photo-alignment material used for the photo-alignment film include JP-A-2006-285197, JP-A-2007-76839, JP-A-2007-138138, JP-A-2007-94071, and JP-A-2007-94071. JP-A-121721, JP-A-2007-140465, JP-A-2007-156439, JP-A-2007-133184, JP-A-2009-109831, JP-A-3883848, and JP-A-4151746. Azo compounds, aromatic ester compounds described in JP-A-2002-229039, maleimide and / or alkenyl substitution having a photo-alignable unit described in JP-A-2002-265541 and JP-A-2002-317013 Nadimide compound, Patent No. 4205195 And, the photocrosslinkable silane derivative described in Patent No. 4205198, JP-T-2003-520878, JP-T-2004-529220, and the photocrosslinkable polyimide, polyamide, or ester described in Patent No. 4162850, And JP-A-9-118717, JP-T-10-506420, JP-T-2003-505561, International Publication No. 2010/150748, JP-A-2013-177561, and JP-A-2014-12823. The compounds which can be photodimerized, especially cinnamate compounds, chalcone compounds and coumarin compounds described in Japanese Patent Application Laid-Open Publication No. H11-163,086 are exemplified. Particularly preferred examples include azo compounds, photocrosslinkable polyimides, polyamides, esters, cinnamate compounds, and chalcone compounds.

The support layer and the alignment film may be provided separately as layers that perform their respective functions, or may be a single layer having both functions.
When a polarizing plate including the retardation film of the present invention and a polarizer described below is produced, the alignment film is not included in the retardation film and is formed on the surface of the polarizer (polarizer layer). (Polarizer with alignment film). In this case, the alignment film is preferably disposed between the retardation film and the polarizer.

The retardation film of the present invention has an in-plane retardation value Re (450) measured at a wavelength of 450 nm, an in-plane retardation value Re (550) measured at a wavelength of 550 nm, and a surface measured at a wavelength of 650 nm. It is preferable that Re (650), which is the value of the internal retardation, has a relationship of Re (450) ≦ Re (550) ≦ Re (650). That is, this relationship can be said to represent the above-described inverse wavelength dispersion.
The method of measuring the in-plane retardation value at each wavelength is as described above.

<Positive A plate>
The retardation film of the present invention is preferably a positive A plate.
In this specification, the positive A plate is defined as follows. The positive A plate (positive A plate) has a refractive index in the slow axis direction in the film plane (direction in which the refractive index in the plane becomes maximum) nx, and is orthogonal to the in-plane slow axis in the plane. When the refractive index in the direction is ny and the refractive index in the thickness direction is nz, the relationship of the formula (A1) is satisfied. The positive A plate has a positive Rth value.
Formula (A1) nx> ny ≒ nz
Note that the above “≒” includes not only a case where both are completely the same but also a case where both are substantially the same. “Substantially the same” means, for example, “ny ≒ nz” when (ny−nz) × d (where d is the thickness of the film) is −10 to 10 nm, preferably −5 to 5 nm. include.

  For details of the manufacturing method of the positive A plate, for example, descriptions in JP-A-2008-225281 and JP-A-2008-026730 can be referred to.

<Λ / 4 plate>
The positive A plate preferably functions as a λ / 4 plate.
The λ / 4 plate is a plate having a function of converting linearly polarized light of a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light), and has an in-plane retardation Re (λ) at a specific wavelength λnm. A plate (retardation film) that satisfies Re (λ) = λ / 4.
This formula may be achieved at any wavelength in the visible light range (for example, 550 nm), and the in-plane retardation Re (550) at a wavelength of 550 nm has a relationship of 110 nm ≦ Re (550) ≦ 160 nm. It is more preferable that the thickness satisfies 110 nm ≦ Re (550) ≦ 150 nm.

(Method of manufacturing retardation film)
The method for forming the retardation film is not particularly limited, and may be a known method.
For example, the polymerizable liquid crystal composition is applied to a predetermined substrate (for example, a support layer described below) to form a coating film, and the obtained coating film is subjected to a curing treatment (irradiation with active energy rays (light irradiation). Treatment) and / or heat treatment), a retardation film including a cured coating film (optically anisotropic layer) can be produced. In addition, you may use the orientation layer mentioned later as needed.
The application of the polymerizable liquid crystal composition can be performed by a known method (for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, or a die coating method).

In the method for forming a retardation film, it is preferable to perform an alignment treatment of a specific liquid crystal compound contained in the coating before performing the curing treatment on the coating. Thereby, it is easy to make the obtained retardation film a positive A plate described later.
The orientation treatment can be performed by drying at room temperature (for example, 20 to 25 ° C.) or by heating. In the case of a thermotropic liquid crystal compound, the liquid crystal phase formed by the alignment treatment can be generally transferred by a change in temperature or pressure. In the case of a lyotropic liquid crystal compound, the transition can be effected also by a composition ratio such as a solvent amount.
For example, when the rod-shaped liquid crystal compound exhibits a smectic phase, the temperature region where the nematic phase is developed is generally higher than the temperature region where the rod-shaped liquid crystal compound exhibits the smectic phase. Therefore, when the specific liquid crystal compound of the present invention is a rod-like liquid crystal, the specific liquid crystal compound is heated to a temperature region where a nematic phase is developed, and then the heating temperature is increased to a temperature region where the specific liquid crystal compound exhibits a smectic phase. By lowering, the specific liquid crystal compound can be changed from a nematic phase to a smectic phase. According to such a method, a positive A plate in which the specific liquid crystal compound is oriented with a high degree of order can be obtained.
In the case where the specific liquid crystal compound is a rod-shaped liquid crystal, in a temperature region where the specific liquid crystal compound exhibits a nematic phase, it is necessary to heat for a certain period of time until the specific liquid crystal compound forms a monodomain. The heating time (heating aging time) is preferably 10 seconds to 5 minutes, more preferably 10 seconds to 3 minutes, and most preferably 10 seconds to 2 minutes.
In the case where the specific liquid crystal compound is a rod-like liquid crystal, it is necessary to heat the rod-like liquid crystal compound for a certain period of time in a temperature range where the specific liquid crystal compound exhibits a smectic phase. The heating time is preferably from 10 seconds to 5 minutes, more preferably from 10 seconds to 3 minutes, and most preferably from 10 seconds to 2 minutes.

The above-described curing treatment (irradiation of active energy rays (light irradiation treatment) and / or heat treatment) on the coating film can also be referred to as a fixing treatment for fixing the orientation of the specific liquid crystal compound.
The immobilization treatment is preferably performed by irradiation with an active energy ray (preferably ultraviolet light), and the liquid crystal is fixed by polymerization of a specific liquid crystal compound.

[Polarizer]
The polarizing plate of the present invention has the above retardation film and a polarizer. The description of the retardation film is as described above, and will not be repeated.

<Polarizer>
The polarizer (polarizing film) may be a so-called linear polarizer having a function of converting light into specific linearly polarized light. The polarizer is not particularly limited, but an absorption polarizer can be used.
The type of polarizer is not particularly limited, and a commonly used polarizer can be used.For example, an iodine-based polarizer, a dye-based polarizer using a dichroic dye, a polyene-based polarizer, and Any of the polarizers using a wire grid can be used. An iodine-based polarizer and a dye-based polarizer are generally produced by adsorbing iodine or a dichroic dye on polyvinyl alcohol and stretching the resultant.
As the polarizer, a thermotropic liquid crystal dichroic dye (for example, a thermotropic liquid crystal dichroic dye used for a light-absorbing anisotropic film described in JP-A-2011-237513) is used. It is also preferable to use a coating type polarizer produced by the method described above. By using a coating type polarizer, it is possible to further reduce the thickness of a polarizer obtained by stretching polyvinyl alcohol. Moreover, even when an external force such as bending is applied, a polarizing plate with little change in optical characteristics can be provided.
Although the thickness of the polarizer is not particularly limited, it is preferably 5 to 40 μm, more preferably 5 to 30 μm, and still more preferably 5 to 20 μm. With the above thickness, the display device can be made thinner.

<Other layers>
(Polarizer protective film)
A polarizer protective film may be arranged on the surface of the polarizer. The polarizer protective film may be disposed only on one surface of the polarizer (on the surface opposite to the retardation film side), or may be disposed on both surfaces of the polarizer.
The structure of the polarizer protective film is not particularly limited, and may be, for example, a transparent support or a hard coat layer, or a laminate of the transparent support and the hard coat layer.
As the hard coat layer, a known layer can be used, and for example, a layer obtained by polymerizing and curing a polyfunctional monomer may be used.
Further, as the transparent support, a known transparent support can be used. For example, as a material for forming the transparent support, a cellulose-based polymer represented by triacetyl cellulose (hereinafter, referred to as cellulose acylate) is used. ), Thermoplastic norbornene-based resins (Zeonex, Zeonor, manufactured by Nippon Zeon Co., Ltd., Arton manufactured by JSR Corporation), acrylic resins, and polyester-based resins can be used.
The thickness of the polarizer protective film is not particularly limited, but is preferably 40 μm or less, more preferably 25 μm or less, because the thickness of the polarizing plate can be reduced.

  An adhesive layer or an adhesive layer may be disposed between the layers to ensure adhesion between the layers. Further, a transparent support may be arranged between the layers.

[Liquid crystal display device and organic electroluminescent device]
The polarizing plate can be preferably used for an organic electroluminescent device (preferably, an organic EL (electroluminescence) display device) and a liquid crystal display device.

<Liquid crystal display device>
The liquid crystal display device of the present invention is an example of an image display device, and includes the above-described polarizing plate of the present invention and a liquid crystal cell.
In the present invention, among the polarizing plates provided on both sides of the liquid crystal cell, it is preferable to use the polarizing plate of the present invention as the front polarizing plate, and the polarizing plate of the present invention as the front and rear polarizing plates. It is more preferable to use Further, it is preferable that the retardation film included in the polarizing plate is disposed on the liquid crystal cell side.
That is, the retardation film of the present invention can be suitably used as an optical compensation film.
Hereinafter, a liquid crystal cell included in the liquid crystal display device will be described in detail.

(Liquid crystal cell)
The liquid crystal cell used for the liquid crystal display device is preferably a VA (Virtual Alignment) mode, an OCB (Optical Compensated Bend) mode, an IPS (In-Place-Switching) mode, or a TN (Twisted Nematic). However, the present invention is not limited to this.
In a TN mode liquid crystal cell, rod-like liquid crystalline molecules are substantially horizontally aligned when no voltage is applied, and further twist-aligned at 60 to 120 °. A TN mode liquid crystal cell is most often used as a color TFT liquid crystal display device, and is described in many documents.
In a VA mode liquid crystal cell, rod-shaped liquid crystalline molecules are substantially vertically aligned when no voltage is applied. VA mode liquid crystal cells include (1) a VA mode liquid crystal cell in a narrow sense in which rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied and substantially horizontally when voltage is applied (Japanese Unexamined Patent Publication No. 176625) and (2) a liquid crystal cell (SID97, Digest of tech. Papers (Preliminary Collection) 28 (1997) 845) in which the VA mode is multi-domain (for MVA mode) in order to enlarge the viewing angle. ), (3) a liquid crystal cell (n-ASM mode) in which rod-like liquid crystal molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is performed when voltage is applied (Preprints 58 to 59 of the Japanese Liquid Crystal Symposium). (1998)) and (4) SURVIVAL mode liquid crystal cell (presented at LCD International 98). Further, any of a PVA (Patterned Vertical Alignment) type, a photo alignment type (Optical Alignment), and a PSA (Polymer-Sustained Alignment) may be used. Details of these modes are described in JP-A-2006-215326 and JP-T-2008-538819.
In the IPS mode liquid crystal cell, rod-like liquid crystal molecules are oriented substantially parallel to the substrate, and the liquid crystal molecules respond planarly when an electric field parallel to the substrate surface is applied. In the IPS mode, black display is performed when no electric field is applied, and the absorption axes of the pair of upper and lower polarizing plates are orthogonal to each other. Japanese Patent Application Laid-Open Nos. H10-54982 and H11-202323 disclose a method of using an optical compensation sheet (optical compensation film) to reduce leakage light at the time of black display in an oblique direction and improve the viewing angle. It is disclosed in JP-A-9-292522, JP-A-11-133408, JP-A-11-305217, and JP-A-10-307291.

<Organic EL display device>
As an organic EL display device which is an example of the organic electroluminescent device of the present invention, for example, an embodiment having the polarizing plate of the present invention and the organic EL display panel in this order from the viewing side is preferable. The retardation film included in the polarizing plate is preferably disposed on the organic EL display panel side.
That is, the retardation film of the present invention is used as a so-called antireflection film.
Further, the organic EL display panel is a display panel configured using an organic EL element in which an organic light emitting layer (organic electroluminescent layer) is sandwiched between electrodes (between a cathode and an anode). The configuration of the organic EL display panel is not particularly limited, and a known configuration is employed.

  Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to this.

[Preparation of polarizing plate]
As described below, polarizing plates of Examples and Comparative Examples used for evaluation of durability against wet heat were produced.

<Example 1>
(Production of Polarizer 1 with Photo-Alignment Film 1)
The support surface of the cellulose triacetate film TD80UL (manufactured by FUJIFILM) was subjected to an alkali saponification treatment. Specifically, the support was immersed in a 1.5 N aqueous sodium hydroxide solution at 55 ° C. for 2 minutes, washed in a water washing bath at room temperature, and neutralized with 0.1 N sulfuric acid at 30 ° C. did. After neutralization, it was washed in a water washing bath at room temperature and dried with hot air at 100 ° C.
A roll-shaped polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an MD (Machine Direction) direction in an aqueous iodine solution and dried to obtain a 20 μm-thick polarizer (polarizing film). A polarizer was prepared by laminating a cellulose triacetate film TD80UL as a polarizer protective film having been subjected to the alkali saponification treatment on one surface of the polarizer.
Further, referring to JP 2012-155308 A and Example 3, a coating liquid 1 for a photo-alignment film was prepared and applied to the other surface of the polarizer with a wire bar. The film was dried with hot air at 60 ° C. for 60 seconds to produce a polarizer 1 with a photo-alignment film 1.

(Preparation of polarizing plate 1)
Subsequently, the following coating solution A-1 for forming a positive A plate A-1 was prepared.
――――――――――――――――――――――――――――――――――
Composition of the coating solution A-1 for forming the positive A plate A-1 ――――――――――――――――――――――――――――――――――
20.00 parts by mass of the following polymerizable compound X-1 40.00 parts by mass of the following specific liquid crystal compound L-1 40.00 parts by mass of the following specific liquid crystal compound L-2 Polymerization initiator (IRGACURE 184, manufactured by BASF)
3.00 parts by mass polymerization initiator (IRGACURE OXE-01, manufactured by BASF)
3.00 parts by mass Organic oxidizing agent A-1 1.00 part by mass Leveling agent (compound T-1 below) 0.20 part by mass cyclopentanone (solvent) 423.11 parts by mass ――――――――――――――――――――――――――

Ultraviolet light was irradiated to the produced polarizer 1 with the photo-alignment film 1 in the atmosphere using an ultra-high pressure mercury lamp. At this time, a wire grid polarizer (ProFlux PPL02, manufactured by Moxtek) was set so as to be parallel to the surface of the photo-alignment film 1, and exposure was performed to perform photo-alignment treatment. The illuminance of the ultraviolet light used at this time was 100 mJ / cm ^{2 in the} UV-A region (ultraviolet A wave, integration of wavelengths from 380 nm to 320 nm).

Next, a coating solution A-1 for forming a positive A plate A-1 was applied on the photo-alignment treated surface using a bar coater. After aging by heating at a film surface temperature of 80 ° C. for 20 seconds and cooling to 55 ° C., the film was irradiated with ultraviolet rays of 1000 mJ / cm ² using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) under air. The polarizing plate 1 was formed by fixing the alignment state. That is, the obtained polarizing plate 1 has a positive A plate A-1 as a retardation film, a photo-alignment film 1, a polarizer 1, and a polarizer protective film arranged in this order.
In the formed positive A plate A-1, the slow axis direction was perpendicular to the absorption axis of the polarizing plate (that is, the specific liquid crystal compound was oriented perpendicular to the absorption axis of the polarizing plate). For the positive A plate A-1, the dependency of Re on the light incident angle and the tilt angle of the optical axis were measured using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments). At 550 nm, Re is 145 nm, Rth is 73 nm, Re (550) / Re (450) is 1.11, Re (650) / Re (550) is 1.01, and the tilt angle of the optical axis is 0 °. The liquid crystal compound had a homogeneous alignment.

<Example 2>
The polarizing plate 2 of Example 2 (retardation film) was produced in the same manner as in Example 1 except that 0.5 parts by mass was used instead of 1 part by mass of the organic oxidizing agent A-1 in Example 1. As a positive A plate A-2).
When the optical characteristics of the positive A plate A-2 were measured, Re was 145 nm, Rth was 73 nm, Re (550) / Re (450) was 1.11, and Re (650) / Re (550) was 1 at a wavelength of 550 nm. 0.01, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

<Example 3>
In Example 1, the polarizing plate 3 of Example 3 (positive as a retardation film) was produced in the same manner as in Example 1 except that 20 parts by mass was used instead of 1 part by mass of the organic oxidizing agent A-1. A plate A-3).
When the optical characteristics of the positive A plate A-3 were measured, Re (550) / Re (450) was 1.11, Re (650) / Re (550) was 1.01, and the tilt angle of the optical axis was 0 °. And the specific liquid crystal compound was in a homogeneous alignment, but Re at a wavelength of 550 nm was 120 nm and Rth was 60 nm, which was lower than that of the positive A plate A-1 of Example 1. This is considered that the specific liquid crystal compound itself was oxidatively decomposed by the excess organic oxidant A-1.

<Example 4>
In Example 1, the polarizing plate 4 of Example 4 was manufactured in the same manner as in Example 1 except that 3.0 parts by mass of the following organic oxidant A-2 was used instead of the organic oxidant A-1. (Having a positive A plate A-4 as a retardation film).
When the optical characteristics of the positive A plate A-4 were measured, Re was 145 nm, Rth was 73 nm, Re (550) / Re (450) was 1.11, and Re (650) / Re (550) was 1 at a wavelength of 550 nm. 0.01, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

<Example 5>
In Example 1, the polarizing plate 5 of Example 5 (retardation) was used in the same manner as in Example 1 except that 10 parts by mass of the following organic oxidant A-3 was used instead of the organic oxidant A-1. (With positive A plate A-5 as film).
When the optical characteristics of the positive A plate A-5 were measured, Re was 137 nm, Rth was 69 nm, Re (550) / Re (450) was 1.11, and Re (650) / Re (550) was 1 at a wavelength of 550 nm. 0.01, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

<Example 6>
The polarizing plate 6 of Example 6 (retardation) was prepared in the same manner as in Example 1 except that 10 parts by mass of the following organic oxidizing agent A-4 was used instead of the organic oxidizing agent A-1. (With positive A plate A-6 as film).
When the optical characteristics of the positive A plate A-6 were measured, Re was 137 nm, Rth was 69 nm, Re (550) / Re (450) was 1.11, and Re (650) / Re (550) was 1 at a wavelength of 550 nm. 0.01, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

<Example 7>
Example 1 was the same as Example 1 except that 100 parts by mass of the following specific liquid crystal compound L-5 was used instead of the polymerizable compound X-1, the specific liquid crystal compound L-1, and the specific liquid crystal compound L-2. The polarizing plate 7 of Example 7 (having a positive A plate A-7 as a retardation film) was formed in the same manner.
When the optical characteristics of the positive A plate A-7 were measured, Re was 130 nm, Rth was 65 nm, Re (550) / Re (450) was 1.19, and Re (650) / Re (550) was 1 at a wavelength of 550 nm. 0.02, the tilt angle of the optical axis was 0.4 °, and the specific liquid crystal compound was homogeneously aligned.

Example 8
Example 1 was the same as Example 1 except that 100 parts by mass of the following specific liquid crystal compound L-6 was used in place of the polymerizable compound X-1, the specific liquid crystal compound L-1, and the specific liquid crystal compound L-2. The polarizing plate 8 of Example 8 (having a positive A plate A-8 as a retardation film) was formed in the same manner.
When the optical characteristics of the positive A plate A-8 were measured, at a wavelength of 550 nm, Re was 130 nm, Rth was 65 nm, Re (550) / Re (450) was 1.18, and Re (650) / Re (550) was 1. 0.01, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

<Example 9>
Example 1 was the same as Example 1 except that 100 parts by mass of the following specific liquid crystal compound L-7 was used instead of the polymerizable compound X-1, the specific liquid crystal compound L-1, and the specific liquid crystal compound L-2. In the same manner, the polarizing plate 9 of Example 9 (having a positive A plate A-9 as a retardation film) was formed.
When the optical characteristics of the positive A plate A-9 were measured, Re was 130 nm, Rth was 65 nm, Re (550) / Re (450) was 1.20, and Re (650) / Re (550) was 1 at a wavelength of 550 nm. 0.05, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

<Example 10>
Example 1 was the same as Example 1 except that 100 parts by mass of the following specific liquid crystal compound L-8 was used in place of the polymerizable compound X-1, the specific liquid crystal compound L-1, and the specific liquid crystal compound L-2. The polarizing plate 10 of Example 10 (having a positive A plate A-10 as a retardation film) was formed in the same manner.
When the optical characteristics of the positive A plate A-10 were measured, Re was 130 nm, Rth was 65 nm, Re (550) / Re (450) was 1.14, and Re (650) / Re (550) was 1 at a wavelength of 550 nm. 0.00, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

<Comparative Examples 1 to 5>
A polarizing plate B1 of Comparative Example 1 (having a positive A plate B1 as a retardation film) was formed in the same manner as in Examples 1, 4 to 6 except that no organic oxidizing agent was used.
Except not using an organic oxidizing agent, the polarizing plates B2 to B5 of Comparative Examples 2 to 5 (each having a positive A plate B2 to B5 as a retardation film) are formed in the same manner as in Examples 7 to 10, respectively. did.
For the positive A plates B1 to B5, Re and Rth, Re (550) / Re (450), and Re (650) / Re (550) at a wavelength of 550 nm were measured in the same manner as in Example 1. The results are shown in Table 1 below.
In addition, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

<Comparative Example 6>
The same procedure as in Example 1 was carried out except that 1.0 parts by mass of the following nitroso compound N-1 was used in place of the organic oxidizing agent A-1 in Example 1, and the polarizing plate B6 (position) of Comparative Example 6 was used. Having a positive A plate B6 as a retardation film).
Further, for the positive A plate B6, Re and Rth, Re (550) / Re (450), and Re (650) / Re (550) at a wavelength of 550 nm were measured in the same manner as in Example 1. The results are shown in Table 1 below.
In addition, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

  In the formula for the nitro compound N-1, “Ph” represents a “phenyl group”.

<Comparative Example 7>
The polarizing plate B7 of Comparative Example 7 (Example 7) was manufactured in the same manner as in Example 1 except that 1.0 part by mass of the organic peroxide N-2 was used instead of the organic oxidizing agent A-1. (Having a positive A plate B7 as a retardation film).
For the positive A plate B7, Re and Rth, Re (550) / Re (450), and Re (650) / Re (550) at a wavelength of 550 nm were measured in the same manner as in Example 1. The results are shown in Table 1 below.
In addition, the tilt angle of the optical axis was 0 °, and the specific liquid crystal compound was homogeneously aligned.

[Evaluation test]
<Wet heat durability test>
The polarizing plates prepared in each of the above Examples and Comparative Examples were bonded together on a glass plate with an adhesive (trade name “SK2057” manufactured by Soken Chemical Co., Ltd.) with the positive A plate facing the glass side.
Using Axo Scan (0 PMF-1, manufactured by Axometrics), the wet heat durability of the retardation value (Re) at a wavelength of 550 nm was evaluated using the following index. The results are shown in Table 1 below.
The wet heat endurance test was performed by leaving the device under an environment of 85 ° C. and 85% RH for 120 hours. If it is evaluated as “A” or more, it can be determined that the durability is good.
AAA: The change in the Re value after the test with respect to the initial Re value is less than 0.5% of the initial value. AAA: The change in the Re value after the test with respect to the initial Re value is 0.5% or more of the initial value. Less than 1% A: Change in Re value after test from initial Re value is 1% or more and less than 2% of initial value B: Change in Re value after test from initial Re value is 2 of initial value % To less than 10% C: The amount of change in the Re value after the test with respect to the initial Re value is 10% or more of the initial value.

<Reduction potential>
For each oxidizing agent used in the above Examples and Comparative Examples, the reduction potential (Ered) was measured as follows.
Specifically, a voltammogram of an oxidizing agent of 1 × 10 ⁻³ M was measured in acetonitrile containing 0.1 M of tetra-n-ethylammonium perchlorate as a supporting electrolyte, and the voltammogram was obtained as a half-wave potential obtained from the measurement. Was. Platinum was used for the working electrode and a saturated calomel electrode (SCE) was used for the reference electrode, and the measurement was performed at 25 ° C.

<Evaluation results>
Table 1 shows the results of the above evaluation tests.

From the results shown in Table 1, when a polarizing plate containing the polymerizable liquid crystal composition containing no organic oxidizing agent of the present invention was produced, the Re value was reduced by 2% or more in a wet heat durability test, and the wet heat It was found that the durability was poor (Comparative Examples 1 to 7).
On the other hand, when a polarizing plate containing the polymerizable liquid crystal composition containing the organic oxidant of the present invention was produced, it was found that the Re value change of less than 2% could be maintained and the wet heat durability was excellent ( Examples 1 to 10).
From the comparison of Examples 1 to 3, when the content of the organic oxidizing agent of the present invention is in the range of 1 to 10 parts by mass relative to 100 parts by mass of the specific liquid crystal compound (Example 1), the wet heat durability is improved. It turned out to be better.
The comparison between Examples 1 and 4 to 6 showed that the use of an organic oxidant having a reduction potential of 0.1 volt or more (Examples 1, 4, and 5) further improved wet heat durability.
The evaluation results of Examples 7 to 10 show that when the organic oxidizing agent of the present invention is contained, even if the structure of the polymerizable liquid crystal compound is different, the wet heat resistance is excellent.

Claims (8)

An organic oxidizing agent represented by the following general formula (A- II ) and a polymerizable liquid crystal compound having reverse wavelength dispersion,
Reduction potential of the organic oxidizing agent state, and are 0.1 volts 0.53 volts,
A polymerizable liquid crystal composition, wherein the content of the organic oxidant is 1 to 12.5 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound .
In the formula (A- II ), R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom or a fluorine atom. The polymerizable liquid crystal composition according to claim 1, wherein the polymerizable liquid crystal compound is a liquid crystal compound represented by the following general formula (II).
L ₁ -G ₁ -D ₁ -Ar-D ₂ -G ₂ -L ₂ (II)
In the general formula (II), D ₁ and D ₂ are each independently a single bond, —CO—O—, —C (＝ S) O—, —CR ¹ R ² —, —CR ¹ R ² —CR ^{3 R 4 -, - O-} CR 1 R 2 -, - CR 1 R 2 -O-CR 3 R 4 -, - CO-O-CR 1 R 2 -, - O-CO-CR 1 R 2 -, —CR ¹ R ² —O—CO—CR ³ R ⁴ —, —CR ¹ R ² —CO—O—CR ³ R ⁴ —, —NR ¹ —CR ² R ³ — or —CO—NR ¹ — .
R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms.
G ₁ and G ₂ each independently represent a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group is -O-, -S-, It may be substituted by -NH-.
L ₁ and L ₂ each independently represent a monovalent organic group, and at least one selected from the group consisting of L ₁ and L ₂ represents a monovalent group having a polymerizable group.
Ar represents a divalent aromatic ring group represented by the following formula (II-1), (II-2), (II-3) or (II-4).
In the general formulas (II-1) to (II-4), Q ₁ represents —CH— or —N—; Q ₂ represents —S—, —O—, or —NR ¹¹ —, R ¹¹ 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, or an aromatic heterocyclic group having 3 to 12 carbon atoms, Z ₁ , Z ₂ and Z ₃ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a monovalent having 6 to 20 carbon atoms. aromatic hydrocarbon group, a halogen atom, a cyano group, a nitro ^group, a ^-NR 12 ^{R 13} or ^{-SR 12,} _{Z 1} and _{Z 2,} also form an aromatic ring or aromatic heterocyclic ring bonded to each other ^{well, R 12} and ^{R 13} are each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms Each A ₁ and _{A 2} are ^{independently, -O -, - NR 21 -} , - a group selected from the group consisting of S- and ^{CO-, R 21} represents a hydrogen atom or a substituent, X is Ax represents a non-metallic atom of a Group 14 to Group 16 to which a hydrogen atom or a substituent may be bonded, and Ax is at least one aromatic group 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 6 carbon atoms which may have a substituent, or an aromatic hydrocarbon ring and an aromatic heterocyclic group having a ring. Represents an organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of rings, the aromatic rings in Ax and Ay may each have a substituent, and Ax and Ay are bonded Te, may form a ring, Q Represents a hydrogen atom or may have a substituent alkyl group having 1 to 6 carbon atoms. A retardation film formed using the polymerizable liquid crystal composition according to claim 1 or 2,
In-plane retardation value Re (450) measured at a wavelength of 450 nm, in-plane retardation value Re (550) measured at a wavelength of 550 nm, and In-plane retardation value Re measured at a wavelength of 650 nm. (650) and Re (450) ≦ Re (550) ≦ Re (650).   The retardation film according to claim 3, wherein the retardation film is a positive A plate.   The retardation film according to claim 4, wherein the positive A plate is a λ / 4 plate.   A polarizing plate, comprising: the retardation film according to claim 3; and a polarizer.   A liquid crystal display device comprising the polarizing plate according to claim 6.   An organic electroluminescent device comprising the polarizing plate according to claim 7.