CN111656230A - Polymerizable liquid crystal composition, polarizing film, method for producing the same, polarizing plate, and display device - Google Patents

Abstract

The present invention relates to a polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound having at least 1 polymerizable group and exhibiting smectic liquid crystallinity, a dichroic dye, and an antioxidant, wherein the polymerizable group of the polymerizable liquid crystal compound is a radical polymerizable group, and the relationship between the antioxidant and the polymerizable liquid crystal compound satisfies formula (1): T1-T2 (1) at 0.8 ℃. Wherein T1 is a phase transition temperature at which the polymerizable liquid crystal compound is brought to 130 ℃ in the atmosphere and the phase transition temperature is measured while cooling to 23 ℃ at 5 ℃/min, and T2 is a phase transition temperature at which the polymerizable liquid crystal compound is brought to the lowest temperature when a mixture of 100 parts by mass of the polymerizable liquid crystal compound and 1 part by mass of the antioxidant is brought to 130 ℃ in the atmosphere and the phase transition temperature is measured while cooling to 23 ℃ at 5 ℃/min.

Description

Polymerizable liquid crystal composition, polarizing film and method for producing the same, polarizing plate and display device

technical field

The present invention relates to a polymerizable liquid crystal composition, a polarizing film, a method for producing the same, a polarizing plate, and a display device including the same.

Background technique

Conventionally, in various image display panels such as liquid crystal display panels and organic electroluminescence (organic EL) display panels, polarizing plates are used by being bonded to image display elements such as liquid crystal cells and organic EL display elements. As such a polarizing plate, a polarizing plate having a structure in which a protective layer such as a triacetyl cellulose film is laminated on at least one side of a polarizing plate via an adhesive layer is known, and the polarizing plate is made of polyethylene Compounds exhibiting dichroism, such as iodine and a dichroic dye, are adsorbed and oriented on an alcohol-based resin film.

In recent years, there has been a demand for further thinning of displays such as image display panels, and further thinning is also demanded for polarizers and polarizers, which are one of the constituent elements. In response to such a demand, for example, a thin host-guest polarizer composed of a polymerizable liquid crystal compound and a compound exhibiting dichroism has been proposed (Patent Document 1 and Patent Document 2).

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Publication No. 2007-510946

Patent Document 2: Japanese Patent Laid-Open No. 2013-37353

SUMMARY OF THE INVENTION

The problem to be solved by the invention

In addition, in recent years, displays have been used in various places including outdoors, and development of polarizers excellent in light resistance has been demanded along with this.

Therefore, an object of the present invention is to provide a polymerizable liquid crystal composition suitable for forming a polymerizable liquid crystal composition having a high suppressing effect against modification of dichroic dyes when exposed to sunlight, and capable of suppressing polarization. Polarizing film (polarizer) that falls over time.

means of solving problems

The inventors of the present application have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have completed the present invention. That is, the present invention provides the following preferred embodiments.

[1] A polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound having at least one polymerizable group and exhibiting smectic liquid crystallinity, a dichroic dye, and an antioxidant, wherein,

The polymerizable group possessed by the polymerizable liquid crystal compound is a radically polymerizable group,

The relationship between the aforementioned antioxidant and the aforementioned polymerizable liquid crystal compound satisfies the formula (1):

0.8℃≤T1-T2 (1)

[In the formula, T1 is the phase transitioning to the liquid crystal phase appearing on the lowest temperature side when the above-mentioned polymerizable liquid crystal compound is heated to 130° C. in the atmosphere, and the phase transition temperature is measured while cooling to 23° C. at 5° C./min. Transition temperature, T2 is the phase transition temperature measured by heating a mixture of 100 parts by mass of the polymerizable liquid crystal compound and 1 part by mass of the antioxidant to 130°C in the atmosphere, and then cooling to 23°C at 5°C/min When, the phase transition temperature to the liquid crystal phase appearing on the lowest temperature side]

[2] The polymerizable liquid crystal composition according to the above [1], which further contains a solvent.

[3] The polymerizable liquid crystal composition according to the above [1] or [2], wherein the dichroic dye is an azo dye.

[4] The polymerizable liquid crystal composition according to any one of the above [1] to [3], wherein the polymerizable group contained in the polymerizable liquid crystal compound is an acryloyloxy group.

[5] The polymerizable liquid crystal composition according to any one of the above [1] to [4], which contains 0.1 to 15 parts by mass of an antioxidant with respect to 100 parts by mass of the polymerizable liquid crystal composition.

[6] The polymerizable liquid crystal composition according to any one of the above [1] to [5], wherein the antioxidant is selected from the group consisting of phenol-based compounds, alicyclic alcohol-based compounds, and amine-based compounds At least 1 species.

[7] The polymerizable liquid crystal composition according to any one of the above [1] to [6], wherein the antioxidant has any structure represented by formulae (2), (3) and (4).

[Chemical formula 1]

[In formulae (2) and (3), R ₁ to R ₅ are each independently -H, -OH, -NH ₂ , a branched or unbranched alkyl group having 1 to 12 carbon atoms, or a carbon atom A branched or unbranched alkoxy group having a number of 1 to 12, in formulas (2) and (3), respectively, at least one of R ₁ to R ₅ is -OH or -NH ₂ ]

[8] The polymerizable liquid crystal composition according to the above [7], wherein the antioxidant is a compound represented by formula (5).

A ₁ -L ₁ -(A ₂ -L ₂ ) _n -A ₃ (5)

[In the formula,

L ₁ and L ₂ are each independently a single bond or a divalent linking group,

A ₁ is a group represented by formula (2), (3) or (4),

[Chemical formula 2]

[In formulae (2) and (3), R ₁ to R ₅ are defined in the same manner as in the aforementioned [7]]

A ₂ is a group represented by formula (6) or (7),

[Chemical formula 3]

[In formulae (6) and (7), R ₆ to R ₉ are each independently -H, -OH, -NH ₂ , a branched or unbranched alkyl group having 1 to 12 carbon atoms, or a carbon atom branched or unbranched alkoxy with 1 to 12]

A ₃ is a group represented by formula (8) or (9),

[Chemical formula 4]

[In formulae (8) and (9), R ₁₀ to R ₁₄ are each independently -H, -OH, -NH ₂ , a branched or unbranched alkyl group having 1 to 12 carbon atoms, or a carbon atom branched or unbranched alkoxy with 1 to 12]

n is an integer of 0 to 2, and when n is 2, the two A _2s may be the same or different from each other].

[9] A polarizing film, which is a cured product of a polymerizable liquid crystal composition comprising a dichroic dye, a polymerizable liquid crystal compound, and an antioxidant,

In the X-ray diffraction measurement, the polarizing film showed a Bragg peak,

The relationship between the aforementioned antioxidant and the aforementioned polymerizable liquid crystal compound satisfies the formula (1):

0.8℃≤T1-T2 (1)

[In the formula, T1 is the phase transitioning to the liquid crystal phase appearing on the lowest temperature side when the above-mentioned polymerizable liquid crystal compound is heated to 130° C. in the atmosphere, and the phase transition temperature is measured while cooling to 23° C. at 5° C./min. Transition temperature, T2 is the phase transition temperature measured by heating a mixture of 100 parts by mass of the polymerizable liquid crystal compound and 1 part by mass of the antioxidant to 130°C in the atmosphere, and then cooling to 23°C at 5°C/min When, the phase transition temperature to the liquid crystal phase appearing on the lowest temperature side]

[10] A polarizing plate comprising the polarizing film and retardation film according to [9] above.

[11] The polarizing plate of the aforementioned [10], wherein the retardation film satisfies the formula (X):

100≤Re(550)≤180 (X)

[In the formula, Re(550) represents the in-plane retardation value at a wavelength of 550 nm]

The angle formed by the slow axis of the retardation film and the absorption axis of the polarizing film is substantially 45°.

[12] The polarizing plate according to the aforementioned [10] or [11], wherein the retardation film satisfies the formula (Y):

Re(450)/Re(550)＜1 (Y)

[In the formula, Re(450) and Re(550) represent the in-plane retardation values at wavelengths of 450 nm and 550 nm, respectively]

[13] The polarizing plate according to any one of the above [10] to [12], wherein the retardation film is composed of a polymer in an aligned state of the polymerizable liquid crystal compound.

[14] A display device including the polarizing film according to the above [9], or the polarizing plate according to any one of the above [10] to [13].

[15] The manufacturing method of polarizing film, it comprises the following steps:

the step of forming a coating film of the polymerizable liquid crystal composition according to any one of the above [1] to [8];

A step of removing the solvent from the aforementioned coating film;

The step of cooling the polymerizable liquid crystal compound to change the phase of the polymerizable liquid crystal compound into a smectic phase after raising the temperature to a temperature equal to or higher than the temperature at which the polymerizable liquid crystal compound changes into a liquid phase; and

A step of polymerizing the polymerizable liquid crystal compound while maintaining the smectic phase.

effect of invention

According to the present invention, a polymerizable liquid crystal composition suitable for forming a polymerizable liquid crystal composition having a high inhibitory effect against modification of a dichroic dye when exposed to sunlight, and capable of inhibiting polarization performance over time can be provided Falling polarizer.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail. In addition, the scope of the present invention is not limited to the embodiment described here, and various changes can be made in the range which does not impair the gist of the present invention.

<Polymerizable liquid crystal composition>

The polymerizable liquid crystal composition of the present invention includes a polymerizable liquid crystal compound (hereinafter, also referred to as "polymerizable liquid crystal compound (A)") which has at least one polymerizable group and exhibits smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizing film having a high degree of alignment order can be formed. The liquid crystal state exhibited by the polymerizable liquid crystal compound (A) is a smectic phase (smectic liquid crystal state), and is more preferably a high-order smectic phase (high-order smectic phase) from the viewpoint of achieving a higher degree of alignment order. crystalline liquid crystal state). Here, the high-order smectic phase refers to smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase, and smectic L phase, among these, smectic B phase, smectic F phase, and smectic I phase are more preferable. The liquid crystallinity may be either a thermotropic liquid crystal or a lyotropic liquid crystal, and a thermotropic liquid crystal is preferable from the viewpoint of enabling dense film thickness control.

The polymerizable liquid crystal compound may be a monomer, or an oligomer or polymer formed by polymerizing a polymerizable group.

The polymerizable liquid crystal compound (A) is a liquid crystal compound having at least one polymerizable group. Here, the polymerizable group refers to a group that can participate in a polymerization reaction by an active radical, an acid, or the like generated by a polymerization initiator.

As the polymerizable group which the polymerizable liquid crystal compound (A) has, vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methyl Acryloyloxy, oxetanyl, oxetanyl, etc. Among them, a radically polymerizable group is preferable, acryloyloxy group, methacryloyloxy group, vinyl group, and vinyloxy group are more preferable, acryloyloxy group and methacryloyloxy group are still more preferable, and propylene group is still more preferable Acyloxy.

The polymerizable liquid crystal compound (A) is not particularly limited as long as it has at least one polymerizable group and exhibits smectic liquid crystallinity, and known polymerizable liquid crystal compounds can be used.

Examples of the polymerizable liquid crystal compound (A) include a compound represented by formula (A1) and a polymer of the compound (hereinafter, the compound and the polymer may be collectively referred to as "polymerizable liquid crystal compound (A1)").

U ¹ -V ¹ -W ¹ -X ¹ -Y ¹ -X ² -Y ² -X ³ -W ² -V ² -U ² (A1)

[In formula (A1),

X ¹ , X ² and X ³ independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, and here, the divalent aromatic group or the divalent alicyclic hydrocarbon group includes The hydrogen atom can be substituted by a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group to form The carbon atom of the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom. However, at least one of X ¹ , X ² and X ³ is an optionally substituted 1,4-phenylene group or an optionally substituted cyclohexane-1,4-diyl group.

Y ¹ and Y ² are independently a single bond or a divalent linking group.

U ¹ represents a hydrogen atom or a polymerizable group.

U ² represents a polymerizable group.

W ¹ and W ² are independently a single bond or a divalent linking group.

V ¹ and V ² independently represent an optionally substituted alkanediyl group having 1 to 20 carbon atoms, and -CH ₂ - constituting the alkanediyl group may be substituted with -O-, -CO-, -S- or NH-. ]

In the polymerizable liquid crystal compound (A1), X ¹ , X ² and X ³ are preferably independently substituted 1,4-phenylene which may have a substituent or cyclohexane-1,4-di which may have a substituent group, at least one of X ¹ , X ² and X ³ is an optionally substituted 1,4-phenylene group or an optionally substituted cyclohexane-1,4-diyl group. In particular, X ¹ and X ³ are preferably cyclohexane-1,4-diyl which may have a substituent, and the cyclohexane-1,4-diyl is more preferably trans-cyclohexane-1,4 - Two bases. A methyl group, an ethyl group, a butyl group, etc. are mentioned as a substituent which the optionally substituted 1,4-phenylene group or the optionally substituted cyclohexane-1,4-diyl group has. An alkyl group having 1 to 4 carbon atoms, a cyano group, and a halogen atom such as a chlorine atom and a fluorine atom. Unsubstituted is preferred. In addition, when Y ¹ and Y ² have the same structure, it is preferable that at least one of X ¹ , X ² and X ³ has a different structure. When at least one of X ¹ , X ² and X ³ has a different structure, there is a tendency that smectic liquid crystallinity is likely to be exhibited.

Y ¹ and Y ² independently of each other preferably represent -CH ₂ CH ₂ -, -CH ₂ O-, -CH ₂ CH ₂ O-, -COO-, -OCOO-, single bond, -N=N-, -CR ^a = CR ^b -, -C≡C-, -CR ^a =N- or -CO-NR ^a -. R ^a and R ^b independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y ¹ is more preferably -CH ₂ CH ₂ -, -COO- or a single bond, and Y ² is more preferably -CH ₂ CH ₂ - or CH ₂ O-. In addition, when all of X ¹ , X ² and X ³ have the same structure, Y ¹ and Y ² preferably have mutually different structures. When Y ¹ and Y ² have mutually different structures, there is a tendency that smectic liquid crystallinity is likely to be exhibited.

U ² is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, preferably a polymerizable group. It is preferable that both U ¹ and U ² are polymerizable groups, and both are preferably radically polymerizable groups. As a polymerizable group, the group similar to the group exemplified above as a polymerizable group which a polymerizable liquid crystal compound (A) has can be mentioned. The polymerizable group represented by U ¹ and the polymerizable group represented by U ² may be different from each other, but are preferably the same group.

Examples of the alkanediyl group represented by V ¹ and V ² include methylene, ethylene, propane-1,3-diyl, butane-1,3-diyl, butane-1,4-diyl base, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, decane-1,10-diyl base, tetradecane-1,14-diyl and eicosane-1,20-diyl, etc. V ¹ and V ² are preferably alkanediyl groups having 2 to 12 carbon atoms, and more preferably alkanediyl groups having 6 to 12 carbon atoms.

As a substituent which this alkanediyl group may have, a cyano group, a halogen atom, etc. are mentioned, This alkanediyl group is preferably an unsubstituted, more preferably an unsubstituted linear alkanediyl group.

As W ¹ and W ² , independently of each other, a single bond, -O-, -S-, -COO- or -OCOO- is preferable, and a single bond or -O- is more preferable.

As a polymerizable liquid crystal compound (A1), the compound represented by Formula (A-1) - Formula (A-25) is mentioned, for example. When the polymerizable liquid crystal compound (A1) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans-isomer.

[Chemical formula 5]

[Chemical formula 6]

[Chemical formula 7]

[Chemical formula 8]

[Chemical formula 9]

Among these, it is preferable to be selected from formula (A-2), formula (A-3), formula (A-4), formula (A-5), formula (A-6), formula (A-7), formula At least 1 member selected from the group consisting of compounds represented by (A-8), formula (A-13), formula (A-14), formula (A-15), formula (A-16) and formula (A-17) kind. As the polymerizable liquid crystal compound (A1), one type may be used alone, or two or more types may be used in combination.

The polymerizable liquid crystal compound (A1) can be produced by a known method described in Lub et al., Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156.

The polymerizable liquid crystal composition of the present invention may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound (A) as long as the effects of the present invention are not impaired. From the viewpoint of obtaining a polarizing film with a high degree of alignment order, the ratio of the polymerizable liquid crystal compound (A) with respect to the total mass of all the polymerizable liquid crystal compounds in the polymerizable liquid crystal composition is preferably 51% by mass or more, More preferably, it is 70 mass % or more, More preferably, it is 90 mass % or more.

When the polymerizable liquid crystal composition of the present invention contains two or more types of polymerizable liquid crystal compounds (A), at least one of them may be the polymerizable liquid crystal compound (A1), or all of them may be the polymerizable liquid crystal compound (A1). By combining a plurality of polymerizable liquid crystal compounds, the liquid crystallinity may be temporarily maintained even at a temperature below the liquid crystal-crystal phase transition temperature.

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition of the present invention is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, even more preferably 40 to 99.9% by mass relative to the solid state content of the polymerizable liquid crystal composition. It is 70-99 mass %. When content of a polymerizable liquid crystal compound is in the said range, there exists a tendency for the orientation of a polymerizable liquid crystal compound to improve.

In the present specification, the term "solid content" means the total amount of the remaining components after removing the solvent from the polymerizable liquid crystal composition.

The polymerizable liquid crystal composition of the present invention contains a dichroic dye. Here, the dichroic dye refers to a dye having a property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction. The dichroic dye that can be used in the present invention is not particularly limited, as long as it is a dichroic dye having the above-mentioned properties, and may be a dye or a pigment. Two or more dyes or pigments may be used in combination, respectively, or dyes and pigments may be used in combination.

As the dichroic dye, a dichroic dye having an absorption maximum wavelength (λ _MAX ) in the range of 300 to 700 nm is preferable. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes.

The azo dyes include monoazo dyes, disazo dyes, trisazo dyes, tetrazo dyes, and stilbene azo dyes, and preferably disazo dyes and trisazo dyes, and examples of the formula include: The compound represented by (I) (hereinafter, also referred to as "compound (I)").

K ¹ -(-N=NK ² ) _p -N=NK ³ (I)

[In formula (I), K ¹ and K ³ independently represent an optionally substituted phenyl group, an optionally substituted naphthyl group, or an optionally substituted monovalent heterocyclic group. K ² represents an optionally substituted p-phenylene group, an optionally substituted naphthalene-1,4-diyl group, or an optionally substituted divalent heterocyclic group. p represents an integer of 1-4. When p is an integer of 2 or more, a plurality of K ² may be the same or different from each other. The -N=N- bond can be replaced by the -C=C-, -COO-, -NHCO-, -N=CH- bond, as long as it is a range that exhibits absorption in the visible light region. ]

Examples of the monovalent heterocyclic group include those obtained by removing one hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. group. The divalent heterocyclic group includes a group obtained by removing two hydrogen atoms from the above-mentioned heterocyclic compound.

As a phenyl group, a naphthyl group, and a monovalent heterocyclic group in K ¹ and K ³ , and a p-phenylene group, a naphthalene-1,4-diyl group, and a divalent heterocyclic group in K ² , it may optionally have The substituents of , include alkyl groups with 1 to 4 carbon atoms; alkoxy groups with 1 to 4 carbon atoms such as methoxy, ethoxy and butoxy; and trifluoromethyl and other carbon atoms. A fluorinated alkyl group of 1 to 4; cyano group; nitro group; halogen atom; An amino group of an alkyl group having 1 to 6 numbers, or an amino group in which two substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms. An unsubstituted amino group is -NH ₂ ) and the like.

Among the compounds (I), compounds represented by any one of the formulae (I-1) to (I-6) are preferred.

[Chemical formula 10]

[In formulas (I-1) to (I-8),

B ¹ to B ³⁰ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (substituted amino group) and unsubstituted amino groups are as defined above), chlorine atoms or trifluoromethyl groups.

n1 to n4 represent integers of 0 to 3 independently of each other.

When n1 is 2 or more, the plurality of B ² may be the same or different from each other,

When n2 is ² or more, a plurality of B6 may be the same or different from each other,

When n3 is 2 or more, the plurality of B ⁹ may be the same or different from each other,

When n4 is 2 or more, the plurality of B ¹⁴ may be the same or different from each other. ]

As said anthraquinone dye, the compound represented by formula (I-9) is preferable.

[Chemical formula 11]

[In formula (I-9),

R ¹ to R ⁸ independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.

R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

As the aforementioned oxazinone dye, the compound represented by the formula (I-10) is preferable.

[Chemical formula 12]

[In formula (I-8),

R ⁹ to R ¹⁵ independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.

R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

As said acridine dye, the compound represented by Formula (I-11) is preferable.

[Chemical formula 13]

[In formula (I-11),

R ¹⁶ to R ²³ independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.

R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

In the formula (I-9), the formula (I-10) and the formula (I-11), the alkyl group having 1 to 6 carbon atoms for R ^x includes methyl, ethyl, propyl, and butyl. A phenyl group, a toluyl group, a xylyl group, a naphthyl group, etc. are mentioned as the aryl group having 6 to 12 carbon atoms.

As said cyanine dye, the compound represented by formula (I-12) and the compound represented by formula (I-13) are preferable.

[Chemical formula 14]

[In formula (I-12),

D ¹ and D ² independently represent a group represented by any one of formulae (I-12a) to (I-12d).

[Chemical formula 15]

n5 represents an integer of 1-3. ]

[Chemical formula 16]

[In formula (I-13),

D ³ and D ⁴ independently represent a group represented by any one of formulae (I-13a) to (1-13h).

[Chemical formula 17]

n6 represents an integer of 1-3. ]

The polymerizable liquid crystal composition of the present invention is excellent in the effect of suppressing the photodegradation of the dichroic dye in the polarizing film when forming the polarizing film, and therefore has weak resistance to light such as ultraviolet rays in sunlight, In the case of a dichroic dye that is prone to photodeterioration, the effect of the present invention can be exhibited particularly remarkably. Therefore, the polymerizable liquid crystal composition of the present invention is particularly advantageous when using a dichroic dye that is prone to photodeterioration. The dichroic dye contained in the polymerizable liquid crystal composition of the present invention is preferably an azo dye.

The content of the dichroic dye in the polymerizable liquid crystal composition of the present invention can be appropriately determined according to the type of the dichroic dye used, etc., but is preferably 0.1 to 50 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound, More preferably, it is 0.1-20 mass parts, More preferably, it is 0.1-12 mass parts. When the content of the dichroic dye is within the above range, the orientation of the polymerizable liquid crystal compound is hardly disturbed, and a polarizing film having a high degree of orientation order can be obtained.

The polymerizable liquid crystal composition of the present invention contains an antioxidant.

In the polymerizable liquid crystal composition of the present invention, the relationship between the antioxidant and the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition satisfies the formula (1):

0.8℃≤T1-T2(1)

In the formula (1), T1 is the phase transition temperature measured when the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition is heated to 130° C. in the atmosphere and cooled to 23° C. at 5° C./min. The phase transition temperature of the liquid crystal phase transition exhibited on the lowest temperature side.

T2 is when the phase transition temperature is measured while cooling to 23°C at 5°C/min after heating a mixture of 100 parts by mass of the polymerizable liquid crystal compound and 1 part by mass of the antioxidant in the air to 130°C, The phase transition temperature of the liquid crystal phase transition exhibited on the lowest temperature side.

When the polymerizable liquid crystal composition of the present invention contains two or more types of polymerizable liquid crystal compounds, a polymerizable liquid crystal compound (mixture) having the same composition as the polymerizable liquid crystal compound constituting the polymerizable liquid crystal composition can be used for T1 and T2 to measure. The detailed measurement method of T1 and T2 is as described in the Example mentioned later.

In general, when the polymerizable liquid crystal compound and the dichroic dye are oriented with a high degree of order, excellent polarization performance can be obtained. However, in such an alignment state, the dichroic dye exists in a state encapsulated by the polymerizable liquid crystal compound, and therefore, there may be a problem that the addition of the antioxidant causes the alignment of the polymerizable liquid crystal compound to be disturbed, resulting in , it is easy to cause the polarization performance to decline.

The polymerizable liquid crystal composition of the present invention can exhibit an excellent effect of suppressing deterioration of polarization performance when forming a polarizing film by including an antioxidant that satisfies the above formula (1).

In the formula (1), T1-T2 is an index showing the influence of the antioxidant on the phase transition temperature in the liquid crystal state. The larger the value of T1-T2, the more similar the molecular structure of the polymerizable liquid crystal compound and the antioxidant is, which means that the polymerizable liquid crystal compound and the antioxidant are oriented together in the liquid crystal state in a state of being further mixed. Therefore, the larger the value of T1-T2 is, the closer the intermolecular distance between the dichroic dye and the antioxidant existing in the state of being encapsulated by the polymerizable liquid crystal compound is, and it is possible not only to exhibit excellent suppression of photodegradation of the dichroic dye In addition, the orientation of the polymerizable liquid crystal compound is hardly disturbed, and it is estimated that a polarizing film having a high degree of orientational order can be obtained.

In the antioxidant contained in the polymerizable liquid crystal composition of the present invention, the value of T1-T2 is 0.8°C or higher, preferably 0.9°C or higher, more preferably 1.0°C or higher, still more preferably 1.2°C or higher, particularly preferably 1.5 ℃ above.

When the value of T1-T2 is less than 0.8°C, the molecular structure of the polymerizable liquid crystal compound is very different from that of the antioxidant, and it is difficult to align the antioxidant and the polymerizable liquid crystal compound with a high degree of order at the same time. As a result, it is difficult to sufficiently exert the effect of suppressing photodegradation with respect to the dichroic dye. On the other hand, when the value of T1-T2 is within the above-mentioned range, the antioxidant can be arranged in the vicinity of the dichroic dye encapsulated by the polymerizable liquid crystal compound, and an excellent suppressing effect on the deterioration of polarization performance can be expected.

In the present invention, the upper limit of T1-T2 is not particularly limited, but is usually 35°C or lower, preferably 30°C or lower, and more preferably 25°C or lower.

In the polymerizable liquid crystal composition, the relationship between the antioxidant and the polymerizable liquid crystal compound satisfies the above formula (1). The antioxidant is not particularly limited, and any known antioxidant can be used as long as it can exhibit the effect of the present invention. . From the viewpoint of having an excellent inhibitory effect against photodegradation of dichroic dyes, a so-called primary antioxidant that captures free radicals and has an action of preventing auto-oxidation is preferable. Therefore, it is more preferable that the antioxidant contained in the polymerizable liquid crystal composition of this invention is at least 1 sort(s) chosen from the group which consists of a phenol type compound, an alicyclic alcohol type compound, and an amine type compound. An antioxidant may be used individually by 1 type, and may be used in combination of 2 or more types.

As antioxidant selected from the group which consists of a phenol type compound, an alicyclic alcohol type compound, and an amine type compound, the compound which has arbitrary structures represented by formula (2), (3), and (4) is mentioned, for example.

[Chemical formula 18]

In formulas (2) and (3), R ₁ to R ₅ are each independently -H, -OH, -NH ₂ , a branched or unbranched alkyl group having 1 to 12 carbon atoms, or a carbon number is a branched or unbranched alkoxy group of 1 to 12, and in formulas (2) and (3), respectively, at least one of R ₁ to R ₅ is -OH or -NH ₂ .

Examples of branched or unbranched alkyl groups having 1 to 12 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, and 2-ethyl. Hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, etc.

Examples of the branched or unbranched alkoxy group having 1 to 12 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, and an octyloxy group. group, 2-ethylhexyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy and the like.

In the formulae (2) and (3), respectively, -OH or -NH ₂ present in at least one of R ₁ to R ₅ is preferably present in R ₁ , and in this case, R ₂ to R ₅ are more preferably: -H, a branched or unbranched alkyl group having 1 to 12 carbon atoms, or a branched or unbranched alkoxy group having 1 to 12 carbon atoms, more preferably -H.

As an antioxidant which has the structure represented by said formula (2), (3) or (4), the compound represented by formula (5) is mentioned, for example.

A ₁ -L ₁ -(A ₂ -L ₂ ) _n -A ₃ (5)

In formula (5), L ₁ and L ₂ are each independently a single bond or a divalent linking group.

A ₁ is a group represented by the above formula (2), (3) or (4).

A ₂ is a group represented by formula (6) or (7).

[Chemical formula 19]

[In formulae (6) and (7), R ₆ to R ₉ are each independently -H, -OH, -NH ₂ , a branched or unbranched alkyl group having 1 to 12 carbon atoms, or a carbon atom branched or unbranched alkoxy with 1 to 12]

A ₃ is a group represented by formula (8) or (9).

[Chemical formula 20]

[In formulae (8) and (9), R ₁₀ to R ₁₄ are each independently -H, -OH, -NH ₂ , a branched or unbranched alkyl group having 1 to 12 carbon atoms, or a carbon atom branched or unbranched alkoxy with 1 to 12]

n is an integer of 0 to 2, and when n is 2, the two A _2s may be the same or different from each other.

As _a divalent linking group in L1 and _L2 , a single bond, an ether group, a carbonyl group, an ester group, an amide group, an azo group, etc. are mentioned. As L ₁ and L ₂ , a bond type which does not absorb visible light as an antioxidant is preferable, a single bond, an ether group, and an ester group are more preferable, and a single bond and an ether group are particularly preferable.

Examples of A ₁ include the same groups as the structures exemplified above as the structures represented by the above formulae (2), (3) and (4), and preferably those represented by the formula (2) or (4) group, more preferably a group represented by formula (2), more preferably R ₁ is -OH, R ₂ to R ₅ are each independently -H or -CH ₃ , particularly preferably all of R ₂ to R ₅ are -H .

A branched alkyl group having 1 to 12 carbon atoms, an unbranched alkyl group having 1 to 12 carbon atoms, and an alkyl group having 1 to 12 carbon atoms represented by R ₆ to R ₁₄ in A ₂ and A ₃ The branched alkoxy group and the unbranched alkoxy group having 1 to 12 carbon atoms, the same as those mentioned above as R ₁ to R ₅ in A ₁ and having 1 carbon atoms. ~12 branched alkyl groups, unbranched alkyl groups with 1 to 12 carbon atoms, branched alkoxy groups with 1 to 12 carbon atoms, and unbranched alkyl groups with 1 to 12 carbon atoms The same group as alkoxy.

In A ₂ , R ₆ to R ₉ are each independently preferably -H or -CH ₃ , more preferably -H, still more preferably all of R ₆ to R ₉ are -H or -CH ₃ , particularly preferably R ₆ to R ₉ All are -H.

In A ₃ , R ₁₂ is a branched or unbranched alkyl group having 1 to 12 carbon atoms, or a branched or unbranched alkoxy group having 1 to 12 carbon atoms, and R ₁₀ , R ₁₁ , and R ₁₃ and R ₁₄ are each independently preferably -H or -CH ₃ , and particularly preferably all of R ₁₀ , R ₁₁ , R ₁₃ and R ₁₄ are -H.

The weight average molecular weight of the antioxidant is preferably 600 or less, more preferably 500 or less, and still more preferably 450 or less.

When the weight average molecular weight of the antioxidant is 600 or less, the antioxidant can be arranged in the vicinity of the dichroic dye without significantly disturbing the orientation of the polymerizable liquid crystal compound, so that the light suppressing the dichroic dye can be further improved. deteriorating effect. Moreover, when the weight average molecular weight of an antioxidant is 400 or less, it becomes difficult to have absorption in a visible light wavelength region, and the fall of polarizing performance can be reduced more effectively, and it is more preferable.

In the polymerizable liquid crystal composition of the present invention, examples of the antioxidant include the following compounds.

[Chemical formula 21]

Among them, antioxidants with small steric hindrance in terms of molecular structure and high linearity tend to align together with the polymerizable liquid crystal compound and tend to be excellent in the effect of suppressing photodegradation of dichroic dyes, and are therefore preferred. The antioxidant in the polymerizable liquid crystal composition of the present invention is not limited thereto, but is preferably 4-n-octyloxyphenol, 4-n-decyloxyphenol, 4-n-dodecyloxyphenol, 4-n-octyloxyphenol, and 4-n-decyloxyphenol. ,4'-biphenol, 4-ethoxy-4'-hydroxybiphenyl, 4-butoxy-4'-hydroxybiphenyl, 4-octoxy-4'-hydroxybiphenyl, 4-decyloxy yl-4'-hydroxybiphenyl, 4-dodecyloxy-4'-hydroxybiphenyl.

The content of the aforementioned antioxidant in the polymerizable liquid crystal composition of the present invention is preferably 0.1 to 15 parts by mass, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound part or more, more preferably 12 parts by mass or less, still more preferably 8 parts by mass or less, and particularly preferably 4 parts by mass or less.

When content of an antioxidant is more than the said lower limit, the light deterioration of a dichroic dye can be suppressed effectively. Moreover, when content of an antioxidant is below the said upper limit, it is hard to disturb the orientation of a polymerizable liquid crystal compound, and the excellent suppressing effect with respect to the light deterioration of a dichroic dye can be expected.

The polymerizable liquid crystal composition of the present invention may contain a polymerization initiator.

The polymerization initiator is a compound capable of initiating a polymerization reaction of the polymerizable liquid crystal compound, and a photopolymerization initiator is preferable in that the polymerization reaction can be initiated under relatively low temperature conditions. Specifically, a photopolymerization initiator that can generate an active radical or an acid by the action of light is mentioned, and among them, a photopolymerization initiator that generates a radical by the action of light is preferable. A polymerization initiator can be used individually or in combination of 2 or more types.

Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts, and sulfonium salts.

As a benzoin compound, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc. are mentioned.

Examples of the benzophenone compound include benzophenone, methyl phthaloylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone and 2,4,6-trimethylbenzophenone, etc.

Examples of the alkyl phenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one, 2-dimethyphenone Methylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2- Diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, Oligomers of 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one, etc.

As the acylphosphine oxide compound, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, etc. are mentioned.

As the triazine compound, 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl) yl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1 ,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)vinyl]-1,3,5-triazine, 2 ,4-bis(trichloromethyl)-6-[2-(furan-2-yl)vinyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6- [2-(4-Diethylamino-2-methylphenyl)vinyl]-1,3,5-triazine and 2,4-bis(trichloromethyl)-6-[2-(3 , 4-Dimethoxyphenyl) vinyl]-1,3,5-triazine and the like.

As the polymerization initiator, a commercially available polymerization initiator can be used. Examples of commercially available polymerization initiators include "Irgacure (registered trademark) 907", "Irgacure (registered trademark) 184", "Irgacure (registered trademark) 651", and "Irgacure (registered trademark) 819" , "Irgacure (registered trademark) 250", "Irgacure (registered trademark) 369" (Ciba Specialty Chemicals, Inc.); "SEIKUOL (registered trademark) BZ", "SEIKUOL (registered trademark) Z", "SEIKUOL (registered trademark) ) BEE" (Seiko Chemical Co., Ltd.); "kayacure (Kayacu) (registered trademark) BP100" (Nihon Kayaku Co., Ltd.); "kayacure (registered trademark) UVI-6992" (manufactured by DOW Chemical Company); "ADEKA OPTOMER SP-152", "ADEKA OPTOMER SP-170" (ADEKA Co., Ltd.); "TAZ-A", "TAZ-PP" (Siber Hegner, Japan); and "TAZ-104" (Sanwa Chemical Co., Ltd.), etc.

When the polymerizable liquid crystal composition contains a polymerization initiator, its content may be appropriately determined according to the type and amount of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition, and it is preferably It is 0.1-30 mass parts, More preferably, it is 0.5-10 mass parts, More preferably, it is 0.5-8 mass parts. When the content of the polymerizable initiator is within the above range, the polymerizable liquid crystal compound can be polymerized without disturbing the orientation of the polymerizable liquid crystal compound.

When the polymerizable liquid crystal composition contains a photopolymerization initiator, it may further contain a photosensitizer. By using a photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound can be further accelerated.

Examples of the photosensitizer include xanthone compounds such as xanthone and thioxanthone (2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene, alkoxy-containing Anthracene compounds such as anthracene (dibutoxyanthracene, etc.); phenothiazine and rubrene, etc. A photosensitizer can be used individually or in combination of 2 or more types.

The content of the photosensitizer in the polymerizable liquid crystal composition of the present invention may be appropriately determined according to the types and amounts of the photopolymerization initiator and the polymerizable liquid crystal compound, and is preferably 0.1 with respect to 100 parts by mass of the polymerizable liquid crystal compound to 30 parts by mass, more preferably 0.5 to 10 parts by mass, still more preferably 0.5 to 8 parts by mass.

The polymerizable liquid crystal composition of the present invention may contain a leveling agent. A leveling agent has the function of adjusting the fluidity|liquidity of a polymerizable liquid crystal composition, and making the coating film obtained by apply|coating this polymerizable liquid crystal composition more flat, and a surfactant is mentioned specifically,. The leveling agent is preferably at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component. A leveling agent can be used individually or in combination of 2 or more types.

As a leveling agent mainly composed of a polyacrylate compound, "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", "BYK- 358N", "BYK-361N", "BYK-380", "BYK-381" and "BYK-392" (BYK Chemie Company) and the like.

As a leveling agent mainly composed of a compound containing a fluorine atom, "MEGAFACE (registered trademark) R-08", MEGAFACE "R-30", MEGAFACE "R-90", MEGAFACE "F-410", MEGAFACE "F-411", MEGAFACE "F-443", MEGAFACE "F-445", MEGAFACE "F-470", MEGAFACE "F-471", MEGAFACE "F-477", MEGAFACE "F-479", MEGAFACE "F-482" and MEGAFACE "F-483" (DIC Corporation); "Surflon (registered trademark) S-381", Surflon "S-382", Surflon "S-383", Surflon "S-393", Surflon "SC-101", Surflon "SC-105", "KH-40" and "SA-100" (AGC Seimi Chemical Co., Ltd.); "E1830", "E5844" (DaikinFine Chemical Kenkyusho, K.K.) ; "EFTOP EF301", "EFTOP EF303", "EFTOP EF351" and "EFTOP EF352" (Mitsubishi Materials Electronic Chemicals Co., Ltd.) and the like.

The content of the leveling agent in the polymerizable liquid crystal composition of the present invention is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the aforementioned range, the polymerizable liquid crystal compound tends to be easily aligned horizontally, and unevenness is less likely to occur, and a smoother polarizing film can be obtained.

The polymerizable liquid crystal composition of the present invention may contain other additives other than a polymerization initiator, a photosensitizer, and a leveling agent. As another additive, a mold release agent, a stabilizer, coloring agents, such as a bluing agent, a flame retardant, a lubricant, etc. are mentioned, for example. When the polymerizable liquid crystal composition contains other additives, the content of the other additives is preferably more than 0% and 20% by mass or less, more preferably more than 0% and 10% by mass or less, relative to the solid content of the polymerizable liquid crystal composition.

The polymerizable liquid crystal composition of the present invention may contain a solvent. Generally, since the viscosity of the compound which shows smectic liquid crystallinity is high, by adding a solvent to a polymerizable liquid crystal composition, application|coating becomes easy, and as a result, formation of a polarizing film often becomes easy. The solvent can be appropriately selected according to the solubility of the polymerizable liquid crystal compound and the dichroic dye, and examples thereof include water, methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, methyl cellosolve, butyl cellosolve, and propylene glycol monolayer. Methyl ether and other alcohol solvents; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, ethyl lactate and other ester solvents; acetone, methyl Ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, methyl isobutyl ketone and other ketone solvents; pentane, hexane, heptane and other aliphatic hydrocarbon solvents; toluene, xylene and other aromatic hydrocarbons Solvents; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene; and the like.

These solvents can be used alone or in combination of two or more. The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 900 parts by mass, and even more preferably 180 to 600 parts by mass relative to 100 parts by mass of the solid content constituting the polymerizable liquid crystal composition.

The polymerizable liquid crystal composition of the present invention can usually be prepared by mixing and stirring a polymerizable liquid crystal compound, a dichroic dye, an antioxidant, and if necessary, the above-mentioned additives, a solvent, and the like.

The polymerizable liquid crystal composition of the present invention has an excellent effect of suppressing photodeterioration of dichroic dyes, and can obtain a polarizing film in which the polarization performance is less likely to deteriorate over time, so it can be suitably used for the production of polarizing films. .

With the polymerizable liquid crystal composition of the present invention, a polarizing film having a high degree of alignment order can be produced.

For a polarizing film with a high degree of orientational order, Bragg peaks derived from higher-order structures such as a hexagonal phase and a crystal phase can be obtained in X-ray diffraction measurement.

的偏光膜。显示出布拉格峰这样的高取向有序度可通过对使用的聚合性液晶化合物的种类、抗氧化剂的种类、其量、二色性色素的种类、其量等进行控制来实现。The Bragg peak refers to a peak derived from the plane periodic structure of molecular orientation. Therefore, in the polarizing film formed from the polymerizable liquid crystal composition of the present invention, the polymerizable liquid crystal compound or a polymer thereof is preferably oriented so that the polarizing film exhibits a Bragg peak in X-ray diffraction measurement, more preferably a polymerizable liquid crystal A "horizontal orientation" in which the molecules of a compound are oriented in the direction in which they absorb light. In the present invention, it is preferable that the plane period interval of molecular orientation is

polarizing film. Exhibiting a high degree of orientational order such as Bragg peaks can be achieved by controlling the type of polymerizable liquid crystal compound used, the type and amount of antioxidant, the type and amount of dichroic dye, and the like.

As described above, by blending an antioxidant whose relationship with the polymerizable liquid crystal composition satisfies the formula (1), it is possible to obtain an excellent inhibitor of dichroic dyes while maintaining the high degree of alignment order of the polymerizable liquid crystal compound. Because of the effect of light deterioration, it is possible to obtain a polarizing film which has excellent polarization performance and is less likely to deteriorate with time in polarization performance. Therefore, the present invention also targets a polarizing film that is a cured product of a polymerizable liquid crystal composition containing a dichroic dye, a polymerizable liquid crystal compound, and an antioxidant, and the polarizing film is measured by X-ray diffraction. A Bragg peak is exhibited, and the relationship between the antioxidant and the polymerizable liquid crystal compound satisfies the formula (1):

0.8℃≤T1-T2 (1)

[In the formula, T1 is the phase transitioning to the liquid crystal phase appearing on the lowest temperature side when the above-mentioned polymerizable liquid crystal compound is heated to 130° C. in the atmosphere, and the phase transition temperature is measured while cooling to 23° C. at 5° C./min. Transition temperature, T2 is the phase transition temperature measured by heating a mixture of 100 parts by mass of the polymerizable liquid crystal compound and 1 part by mass of the antioxidant to 130°C in the atmosphere, and then cooling to 23°C at 5°C/min When, the phase transition temperature to the liquid crystal phase appearing on the lowest temperature side]

In the polymerizable liquid crystal composition used in order to form the polarizing film of the present invention, as the polymerizable liquid crystal compound, the dichroic dye, and the antioxidant, the polymerizable liquid crystal composition contained in the polymerizable liquid crystal composition of the present invention is exemplified. The liquid crystal compound, the dichroic dye, and the antioxidant are the same as those exemplified above. The polymerizable liquid crystal composition used for forming the polarizing film of the present invention may contain a polymerization initiator, a leveling agent, other additives, a solvent, and the like. As these components, the same thing as the thing exemplified above as a component contained in the polymerizable liquid crystal composition of this invention is mentioned.

The polarizing film of the present invention can be produced, for example, by a method comprising the following steps:

a step of forming a coating film of the polymerizable liquid crystal composition of the present invention;

A step of removing the solvent from the aforementioned coating film;

a step of heating the polymerizable liquid crystal compound to a temperature equal to or higher than the temperature at which the phase of the polymerizable liquid crystal compound changes into a liquid phase, and then cooling the polymerizable liquid crystal compound to change the phase of the polymerizable liquid crystal compound into a smectic phase (smectic liquid crystal state); and

A step of polymerizing the polymerizable liquid crystal compound while maintaining the aforementioned smectic phase (smectic liquid crystal state).

The formation of the coating film of the polymerizable liquid crystal composition can be carried out by coating the polymerizable liquid crystal composition, especially the polymerizable liquid crystal composition (hereinafter, also referred to as "the composition for forming a polarizing film") whose viscosity has been adjusted by adding a solvent It is performed on a base material, an alignment film to be described later, or the like. The polymerizable liquid crystal composition can be directly applied to the retardation film and other layers constituting the polarizing plate of the present invention.

The substrate is usually a transparent substrate. When the base material is not provided on the display surface of the display element, for example, when the laminate obtained by removing the base material from the polarizing film is provided on the display surface of the display element, the base material may be opaque. The term "transparent substrate" refers to a substrate having transparency that can transmit light, especially visible light, and the term "transparency" refers to a transmittance of 80% or more with respect to light having a wavelength in the range of 380 to 780 nm. characteristics. As a specific transparent base material, a translucent resin base material is mentioned. Examples of the resin constituting the light-transmitting resin substrate include polyolefins such as polyethylene and polypropylene; cyclic olefin-based resins such as norbornene-based polymers; polyvinyl alcohol; polyethylene terephthalate; Polymethacrylates; Polyacrylates; Triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate and other cellulose esters; Polyethylene naphthalate; Polycarbonate; Polysulfone ; polyether sulfone; polyether ketone; polyphenylene sulfide and polyphenylene ether, etc. From the viewpoints of availability and transparency, polyethylene terephthalate, polymethacrylate, cellulose ester, cyclic olefin-based resin, or polycarbonate is preferable. Cellulose ester is a product obtained by esterifying a part or all of hydroxyl groups contained in cellulose, and is readily available in the market. In addition, cellulose ester substrates are also readily available in the market. As a commercially available cellulose ester base material, "Fujitac Film" (Fujifilm Corporation); "KC8UX2M", "KC8UY", and "KC4UY" (Konica Minolta Opto Products Co., Ltd.) etc. are mentioned.

The properties required for the substrate vary depending on the configuration of the polarizing film, but generally, a substrate with as little retardation as possible is preferable. As a base material having as small retardation property as possible, the cellulose ester film etc. which do not have retardation, such as ZeroTAC (Konica Minolta Opto, Inc.) and Z-TAC (Fujifilm Corporation), are mentioned. An unstretched cyclic olefin-based resin substrate is also preferred. A hard coat treatment, an antireflection treatment, an antistatic treatment, etc. may be applied to the surface of the base material on which the polarizing film is not laminated.

When the thickness of the base material is too thin, the strength decreases and the workability tends to be poor. Therefore, it is usually 5 to 300 μm, preferably 20 to 200 μm, and more preferably 20 to 100 μm.

Examples of methods for applying the composition for forming a polarizing film to a substrate or the like include coating methods such as spin coating, extrusion, gravure coating, die coating, bar coating, and applicator methods. A known method such as a printing method such as a flexographic method.

Next, a dry coating film can be formed by removing the solvent by drying or the like under the condition that the polymerizable liquid crystal compound contained in the coating film obtained from the composition for forming a polarizing film is not polymerized. As a drying method, a natural drying method, a ventilation drying method, a heating drying, a vacuum drying method, etc. are mentioned.

In addition, in order to change the phase of the polymerizable liquid crystal compound into a liquid phase, the temperature is lowered after the temperature is higher than the temperature at which the polymerizable liquid crystal compound changes into a liquid phase, and the polymerizable liquid crystal compound is changed into a smectic phase (smectic liquid crystal state). The phase transition may be performed after the removal of the solvent in the coating film, or may be performed simultaneously with the removal of the solvent.

By polymerizing the polymerizable liquid crystal compound while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, a cured film of the polymerizable liquid crystal composition is formed as a polarizing film. As the polymerization method, a photopolymerization method is preferable. In the photopolymerization, the light irradiated to the dry coating film can be determined according to the type of the photopolymerization initiator and the type of the polymerizable liquid crystal compound (especially the polymerizable group contained in the polymerizable liquid crystal compound) contained in the dry coating film. type) and its amount are appropriately selected. Specific examples thereof include at least one light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays, and active electron beams. Among them, ultraviolet light is preferable from the viewpoints that it is easy to control the progress of the polymerization reaction and that an apparatus widely used in this field can be used as a photopolymerization apparatus, and it is preferable to select the polymerizability in advance so that the photopolymerization can be carried out by ultraviolet light. The type of polymerizable liquid crystal compound and photopolymerization initiator contained in the liquid crystal composition. In addition, at the time of polymerization, the polymerization temperature can also be controlled by irradiating light while cooling the dried coating film by an appropriate cooling means. By employing such a cooling means, if the polymerization of the polymerizable liquid crystal compound is carried out at a relatively low temperature, a polarizing film can be appropriately formed even if a substrate with low heat resistance is used as the substrate. During photopolymerization, a patterned polarizing film can also be obtained by performing shielding, development, or the like.

Examples of the light source for the active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, and emission wavelengths ranging from 380 to 440 nm. LED light source, chemical lamp, black light lamp, microwave excited mercury lamp, metal halide lamp, etc.

The ultraviolet irradiation intensity is usually 10 to 3,000 mW/cm ² . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activation of the photopolymerization initiator. The light irradiation time is usually 0.1 second to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and even more preferably 10 seconds to 1 minute. When irradiated one or more times with such ultraviolet irradiation intensity, the cumulative light amount is 10 to 3,000 mJ/cm ² , preferably 50 to 2,000 mJ/cm ² , and more preferably 100 to 1,000 mJ/cm ² .

By carrying out photopolymerization, the polymerizable liquid crystal compound is polymerized while maintaining a smectic phase, preferably a liquid crystal state of a higher-order smectic phase, to form a polarizing film. A polarizing film obtained by polymerizing a polymerizable liquid crystal compound in a state of maintaining a smectic liquid crystal phase is also accompanied by the action of the aforementioned dichroic dye, which is different from a conventional host-guest polarizing film, that is, a direct Compared with the polarizing film formed in the liquid crystal state of the nematic phase, it has the advantage of high polarization performance. Moreover, compared with the film which apply|coated only a dichroic dye and a lyotropic liquid crystal, there exists an advantage of being excellent in intensity|strength.

The thickness of the polarizing film can be appropriately selected according to the applicable display device, but is preferably 0.1 to 10 μm, more preferably 0.3 to 4 μm, and further preferably 0.5 to 3 μm.

The polarizing film is preferably formed on the alignment film. This alignment film is a film which has the alignment regulation force which orientates a polymerizable liquid crystal compound in a desired direction of liquid crystal. As the alignment film, it is preferable to have solvent resistance that does not dissolve due to application of a polymerizable liquid crystal compound-containing composition, etc., and to have heat resistance during heat treatment for removing the solvent and orienting the polymerizable liquid crystal compound. sex. The alignment film includes an alignment film containing an alignment polymer, a photo alignment film, a groove alignment film having a concavo-convex pattern and a plurality of grooves on the surface, a stretched film stretched in the alignment direction, and the like. From the viewpoint of the accuracy and quality of the orientation angle, a photo-alignment film is preferable.

Examples of the oriented polymer include polyamides having an amide bond in the molecule, gelatins, polyimides having an imide bond in the molecule, and polyamic acid, polyvinyl alcohol, alkane and hydrolyzates thereof. base-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylate. Among them, polyvinyl alcohol is preferable. An orientation polymer can be used individually or in combination of 2 or more types.

An alignment film containing an alignment polymer is usually obtained by applying a composition obtained by dissolving the alignment polymer in a solvent (hereinafter, sometimes referred to as an "alignment polymer composition") on a substrate , the solvent is removed; or, the oriented polymer composition is applied to the substrate, the solvent is removed, and rubbing (rubbing method) is performed. As a solvent, the same solvent as the solvent exemplified above as a solvent which can be used when forming a polarizing film is mentioned.

The concentration of the oriented polymer in the oriented polymer composition may be in a range in which the oriented polymer material can be completely dissolved in the solvent, and is preferably 0.1 to 20 in terms of solid content relative to the solution. %, more preferably about 0.1 to 10%.

As the alignment polymer composition, a commercially available alignment film material can be used as it is. As a commercially available alignment film material, SUNEVER (registered trademark, manufactured by Nissan Chemical Industry Co., Ltd.), OPTOMER (registered trademark, manufactured by JSR Corporation), etc. are mentioned.

As a method of apply|coating an orientation polymer composition to a base material, the method similar to the method illustrated as a method of apply|coating the composition for polarizing film formation to a base material is mentioned.

As a method of removing the solvent contained in the oriented polymer composition, a natural drying method, a ventilation drying method, a heat drying method, a vacuum drying method, etc. are mentioned.

In order to impart an alignment restricting force to the alignment film, a rubbing treatment (rubbing method) may be performed as necessary.

As a method of imparting an orientation restricting force by a rubbing method, a rubbing roll that is wound around a rubbing cloth and is rotated, and a rubbing roll that is applied to a substrate and annealed with an orientation polymer composition on the surface of the substrate can be mentioned. A method of forming a film of oriented polymer contact.

The photo-alignment film is usually prepared by applying a composition containing a polymer or monomer having a photoreactive group and a solvent (hereinafter, also referred to as a "composition for forming a photo-alignment film") on a substrate, and irradiating with polarized light (preferably polarized UV light). The photo-alignment film is more preferable because the direction of the alignment regulating force can be arbitrarily controlled by selecting the polarization direction of the polarized light to be irradiated.

The photoreactive group refers to a group that generates liquid crystal alignment ability by light irradiation. Specifically, there may be mentioned groups that participate in photoreactions such as orientation induction of molecules by light irradiation, isomerization reaction, dimerization reaction, photocrosslinking reaction, or photolysis reaction, which are the origin of liquid crystal alignment ability. . Among them, a group that participates in a dimerization reaction or a photocrosslinking reaction is preferable because it is excellent in orientation. The photoreactive group is preferably a group having an unsaturated bond, especially a double bond, and particularly preferably a group selected from the group consisting of carbon-carbon double bond (C=C bond), carbon-nitrogen double bond (C=N bond), A group of at least one selected from the group consisting of a nitrogen-nitrogen double bond (N=N bond) and a carbon-oxygen double bond (C=O bond).

基、及具有氧化偶氮苯结构的基团。作为具有C＝O键的光反应性基团，可举出二苯甲酮基、香豆素基、蒽醌基及马来酰亚胺基。这些基团可以具有烷基、烷氧基、芳基、烯丙基氧基、氰基、烷氧基羰基、羟基、磺酸基、卤代烷基等取代基。As a photoreactive group which has a C=C bond, a vinyl group, a polyalkenyl group, a stilbene group, a stilbazolyl group, a stilbazolium group, a chalcone group, a cinnamoyl group, etc. are mentioned. As a photoreactive group which has a C=N bond, the group which has structures, such as an aromatic Schiff base and an aromatic hydrazone, is mentioned. Examples of the photoreactive group having an N=N bond include an azophenyl group, an azonaphthyl group, an aromatic heterocyclic azo group, a disazo group, and a methyl group.

groups, and groups having an azobenzene oxide structure. As a photoreactive group which has a C=O bond, a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group are mentioned. These groups may have substituents such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, a haloalkyl group, and the like.

Among them, a photoreactive group that participates in a photodimerization reaction is preferable, and cinnamon is preferable from the viewpoint that the amount of polarized light irradiation required for photoalignment is small, and it is easy to obtain a photoalignment film excellent in thermal stability and temporal stability. Acyl and chalcone groups. As a polymer which has a photoreactive group, the terminal part of this polymer side chain which has a cinnamoyl group which becomes a cinnamic acid structure is especially preferable.

A photo-alignment induction layer can be formed on a base material by apply|coating the composition for photo-alignment film formation on a base material. As the solvent contained in the composition, the same solvent as the solvent exemplified above as the solvent that can be used in the formation of the polarizing film can be mentioned, and the solvent may vary depending on the amount of the polymer or monomer having a photoreactive group. The solubility is appropriately selected.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be appropriately adjusted according to the type of polymer or monomer and the thickness of the target photo-alignment film, relative to the composition for forming a photo-alignment film. In terms of the mass of the material, it is preferably at least 0.2 mass %, and more preferably in the range of 0.3 to 10 mass %. The composition for forming a photo-alignment film may contain a polymer material such as polyvinyl alcohol and polyimide, and a photosensitizer within a range not significantly impairing the properties of the photo-alignment film.

As a method of apply|coating the composition for photo-alignment film formation to a base material, the method similar to the method of apply|coating an orientation composition to a base material is mentioned. As a method for removing the solvent from the applied composition for forming a photo-alignment film, a natural drying method, a ventilation drying method, a heating drying method, a reduced pressure drying method, etc. are mentioned.

In order to irradiate polarized light, a form obtained by removing the solvent from the composition for forming a photo-alignment film applied on a substrate may be directly irradiated with polarized UV light, or it may be irradiated with polarized light from the substrate side to allow A form in which polarized light is transmitted and illuminated. The polarized light is particularly preferably substantially parallel light. The wavelength of the polarized light to be irradiated may be a wavelength in a wavelength region in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) having a wavelength in the range of 250 to 400 nm is particularly preferable. Examples of the light source used for the polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, and ultraviolet lasers such as KrF and ArF, and more preferred are high-pressure mercury lamps, ultra-high pressure mercury lamps, and metal halide lamps. Among these, a high-pressure mercury-vapor lamp, an ultra-high-pressure mercury-vapor lamp, and a metal halide lamp are preferable because the luminous intensity of ultraviolet rays having a wavelength of 313 nm is large. Polarized UV light can be irradiated by irradiating light from the light source through an appropriate polarizer. As the polarizer, polarizing filters, polarizing prisms such as Glan-Thompson and Glan-Taylor, and wire grid polarizers can be used.

In addition, at the time of rubbing or polarized light irradiation, if shielding is performed, the some area|region (pattern) which differs in the direction of liquid crystal orientation can also be formed.

The groove alignment film is a film having a concavo-convex pattern or a plurality of grooves (grooves) on the film surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves arranged at equal intervals, the liquid crystal molecules are aligned in a direction along the grooves.

As a method of obtaining a trench alignment film, a method of exposing the surface of the photosensitive polyimide film through an exposure mask having a slit in a pattern shape, and then performing development and rinsing treatment can be exemplified. A method of forming a concavo-convex pattern; a method of forming a UV-curable resin layer before curing on a plate-shaped original plate having grooves on the surface, transferring the formed resin layer to a substrate, and then curing it; A method in which a grooved roll-shaped original plate is pushed against a film of a UV-curable resin before curing formed on a substrate to form concavities and convexities, and then cured; and the like.

The thickness of the alignment film (the alignment film or photo-alignment film containing the alignment polymer) is usually in the range of 10 to 10,000 nm, preferably in the range of 10 to 1,000 nm, more preferably 500 nm or less, still more preferably 10 to 200 nm, and particularly preferably 50 to 150 nm range.

The present invention includes a polarizing plate (elliptically polarizing plate) including the polarizing film and retardation film of the present invention. In the polarizing plate of the present invention, the retardation film preferably satisfies the formula (X):

100≤Re(550)≤180 (X)

[In the formula, Re(550) represents the in-plane retardation value at a wavelength of 550 nm]

When the retardation film has the in-plane retardation value represented by the above (X), it functions as a so-called λ/4 plate. The aforementioned formula (X) is preferably 100 nm≦Re(550)≦180 nm, and more preferably 120 nm≦Re(550)≦160 nm. In addition, Re(550) can be measured by the method described in an Example.

In the polarizing plate of the present invention, the angle formed by the slow axis of the retardation film and the absorption axis of the polarizing film is preferably substantially 45°. In addition, in this invention, "substantially 45°" means 45°±5°.

In addition, the retardation film preferably satisfies the formula (Y):

Re(450)/Re(550)＜1 (Y)

[In the formula, Re(450) and Re(550) represent the in-plane retardation values at wavelengths of 450 nm and 550 nm, respectively]

The retardation film satisfying the above formula (Y) has so-called reverse wavelength dispersion, and exhibits excellent polarization performance. The value of Re(450)/Re(550) is preferably 0.93 or less, more preferably 0.88 or less, still more preferably 0.86 or less, preferably 0.80 or more, and more preferably 0.82 or more.

The retardation film may be a stretched film that imparts retardation by stretching a polymer, but is preferably a polymerizable liquid crystal composition (hereinafter, also referred to as a polymerizable liquid crystal compound) containing a polymerizable liquid crystal compound from the viewpoint of thinning the polarizing plate. It is called the hardened|cured material of "polymerizable liquid crystal composition (B)"), and consists of the polymer in the orientation state of the said polymerizable liquid crystal compound. The polymerizable liquid crystal compound forming the retardation film (hereinafter, also referred to as "polymerizable liquid crystal compound (B)") refers to a liquid crystal compound having a polymerizable functional group, especially a photopolymerizable functional group. The photopolymerizable functional group refers to a group that can participate in a polymerization reaction by an active radical, an acid, or the like generated by a photopolymerization initiator. Examples of the photopolymerizable functional group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, and oxirane. base, oxetanyl, etc. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxetanyl group, and an oxetanyl group are preferable, and an acryloxy group is more preferable. In the polymerizable liquid crystal compound (B), the liquid crystallinity may be a thermotropic liquid crystal or a lyotropic liquid crystal, and the phase ordered structure may be a nematic liquid crystal or a smectic liquid crystal. As the polymerizable liquid crystal compound (B), only one type may be used, or two or more types may be used in combination.

As the polymerizable liquid crystal compound (B), from the viewpoints of ease of film formation and imparting retardation properties represented by the aforementioned formula (Y), compounds that satisfy all of the following (I) to (IV) can be mentioned. .

(I) a compound having thermotropic liquid crystallinity;

(II) It has π electrons in the long axis direction (a) of the polymerizable liquid crystal compound.

(III) It has π electrons in a direction intersecting with the long axis direction (a) [intersection direction (b)].

(IV) The total number of π electrons present in the long axis direction (a) is represented by N(πa), and the total number of molecular weights present in the long axis direction is represented by N(Aa), and the polymerization is defined by the formula (i) The π electron density in the long axis direction (a) of the liquid crystal compound:

D(πa)=N(πa)/N(Aa) (i)

The total number of π electrons present in the cross direction (b) is referred to as N(πb), and the total number of molecular weights present in the cross direction (b) is referred to as N(Ab), and the polymerizable liquid crystal is defined by the formula (ii) The π electron density in the cross direction (b) of the compound:

D(πb)=N(πb)/N(Ab) (ii)

The D(πa) and the D(πb) satisfy the relationship of 0≤[D(πa)/D(πb)]≤1 [that is, the π electron density in the cross direction (b) is greater than that in the long axis direction (a) π electron density].

A nematic phase can be formed by applying a polymerizable liquid crystal compound (B) that satisfies all of the above (I) to (IV) on an alignment film formed by a rubbing treatment and heating to a phase transition temperature or higher. The nematic phase formed by aligning the polymerizable liquid crystal compound (B) is usually oriented so that the long axis directions of the polymerizable liquid crystal compound are parallel to each other, and the long axis direction becomes the alignment direction of the nematic phase.

The polymerizable liquid crystal compound (B) having the above-mentioned properties usually exhibits reverse wavelength dispersion. As a compound which satisfies the said characteristics (I)-(IV), the compound represented by formula (II) is mentioned, for example.

[Chemical formula 22]

The compound represented by the said formula (II) can be used individually or in combination of 2 or more types.

In formula (II), Ar represents a divalent aromatic group which may have a substituent. The aromatic group as used herein refers to a group having a planar cyclic structure, and the number of π electrons contained in the cyclic structure is [4n+2] according to Huckel's rule. Here, n represents an integer. When a ring structure is formed by including heteroatoms such as -N= and -S-, the case where the non-covalent electron pair on these heteroatoms satisfies the Huckel's rule and has aromaticity is also included. It is preferable that the divalent aromatic group contains at least one of a nitrogen atom, an oxygen atom, and a sulfur atom.

G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be replaced by a halogen atom, an alkyl group having 1 to 4 carbon atoms, or a fluorocarbon having 1 to 4 carbon atoms. group, alkoxy group having 1 to 4 carbon atoms, cyano group or nitro group, and the carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be replaced by oxygen atom, sulfur atom or nitrogen Atomic replacement.

L ¹ , L ² , B ¹ and B ² are each independently a single bond or a divalent linking group.

k and l each independently represent an integer of 0 to 3, and satisfy the relationship of 1≤k+l. Here, when 2≦k+l is satisfied, B ¹ and B ² , and G ¹ and G ² may be the same or different from each other, respectively.

E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, wherein the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and -CH ₂ - contained in the alkanediyl group may be Replaced by -O-, -S-, -Si-. P ¹ and P ² independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

G ¹ and G ² are each independently preferably 1,4-phenylenediyl which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, 1,4-cyclohexanediyl which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1,4-cyclohexanediyl substituted with a methyl group -phenylene, unsubstituted 1,4-phenylene, or unsubstituted 1,4-trans-cyclohexanediyl, particularly preferably unsubstituted 1,4-phenylene, or unsubstituted 1,4-trans-cyclohexanediyl. It is preferable that at least one of G ¹ and G ² present in plural is a divalent alicyclic hydrocarbon group, and it is more preferable that at least one of G ¹ and G ² bonded to L ¹ or L ² is a divalent hydrocarbon group. Alicyclic hydrocarbon group.

L ¹ and L ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2 -, -R ^a3 COOR ^a4 -, -R ^a5 OCOR ^a6 -, R ^a7 OC=OOR ^a8 -, -N=N-, -CR ^c =CR ^d -, or -C≡C-. Here, R ^a1 to R ^a8 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1 -, -CH ₂ -, -CH ₂ CH ₂ -, ^{-COOR a4-1 -, or -OCOR a6-1 -} . Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent any one of a single bond, -CH ₂ -, and -CH ₂ CH ₂ -. L ¹ and L ² are each independently more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, or -OCO-.

In a preferred embodiment of the present invention, at least one of G ¹ and G ² in formula (II) can be used as a divalent alicyclic hydrocarbon group, and the divalent alicyclic hydrocarbon group may have a substituent A polymerizable liquid crystal compound obtained by bonding the divalent aromatic group Ar and L ¹ and/or L ² as -COO-.

B ¹ and B ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a9 OR ^a10 -, -R ^a11 COOR ^a12 -, -R ^a13 OCOR ^a14 -, or R ^a15 OC=OOR ^a16 -. Here, R ^a9 to R ^a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B ¹ and B ² are each independently more preferably a single bond, -OR ^a10-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^{a12 -1} -, or -OCOR ^a14-1 -. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 each independently represent any one of a single bond, -CH ₂ -, and -CH ₂ CH ₂ -. B ¹ and B ² are each independently more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, -OCO-, or -OCOCH ₂ CH ₂ -.

From the viewpoint of exhibiting inverse wavelength dispersion, k and l are preferably in the range of 2≤k+l≤6, preferably k+l=4, and more preferably k=2 and l=2. When k=2 and l=2, since a symmetrical structure is obtained, it is more preferable.

E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

Examples of the polymerizable group represented by P ¹ or P ² include epoxy group, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, Methacryloyloxy, oxetanyl, oxetanyl and the like. Among these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxetanyl group, and an oxetanyl group are preferable, and an acryloxy group is more preferable.

Ar preferably has at least one selected from the group consisting of an optionally substituted aromatic hydrocarbon ring, an optionally substituted aromatic heterocyclic ring, and an electron withdrawing group. As this aromatic hydrocarbon ring, a benzene ring, a naphthalene ring, an anthracene ring, etc. are mentioned, A benzene ring and a naphthalene ring are preferable. Examples of the aromatic heterocyclic ring include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, and a triazine ring. , pyrroline ring, imidazole ring, pyrazole ring, thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring, etc. Among these, it is preferable to have a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is more preferable to have a benzothiazolyl group. When a nitrogen atom is included in Ar, the nitrogen atom preferably has π electrons.

In formula (II), the total number N _π of π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, still more preferably 14 or more, and particularly preferably 16 or more. It is preferably 30 or less, more preferably 26 or less, and still more preferably 24 or less.

As an aromatic group represented by Ar, the group of formula (Ar-1) - formula (Ar-23) is mentioned, for example.

[Chemical formula 23]

In formulas (Ar-1) to (Ar-23), the symbol * represents a linking portion, and Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, cyano group, nitro group, alkylsulfinyl group having 1 to 12 carbon atoms, alkylsulfonyl group having 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group having 1 to 12 carbon atoms, carbon number Alkoxy group having 1 to 6 carbon atoms, alkylthio group having 1 to 12 carbon atoms, N-alkylamino group having 1 to 12 carbon atoms, N,N-dioxane having 2 to 12 carbon atoms amino, N-alkylsulfamoyl having 1 to 12 carbon atoms, or N,N-dialkylsulfamoyl having 2 to 12 carbon atoms.

Q ¹ and Q ² each independently represent -CR ^{2' R} 3'-, -S-, -NH-, -NR 2'-, -CO- or -O-, and R ^{2 '} and R ^3' each independently Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

J ¹ and J ² each independently represent a carbon atom or a nitrogen atom.

Y ¹ , Y ² and Y ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.

W ¹ and W ² each independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.

Examples of the aromatic hydrocarbon group in Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, and a biphenyl group. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a biphenyl group, and the like, and a phenyl group and a naphthyl group are preferable, and a phenyl group is more preferable.

As an aromatic heterocyclic group, the C4-C20 aromatic heterocyclic group containing at least one hetero atom (a nitrogen atom, an oxygen atom, a sulfur atom, etc.) is mentioned. Examples of the aromatic heterocyclic group include furyl, pyrrolyl, thienyl, pyridyl, thiazolyl, benzothiazolyl, and the like, and preferred are furyl, thienyl, pyridyl, thiazolyl, and benzothiazolyl.

Y ¹ and Y ² may each independently be a substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group.

The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from a collection of aromatic rings. The polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from a collection of aromatic rings.

Z ⁰ , Z ¹ and Z ² are each independently preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 12 carbon atoms, and Z ⁰ More preferred are a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyano group. More preferably, Z ¹ and Z ² are a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

As Q ¹ and Q ² , -NH-, -S-, -NR ^2' -, and -O- are preferable, and R ^2' is preferably a hydrogen atom. As Q ¹ and Q ² , -S-, -O-, and -NH- are particularly preferred.

Among the formulae (Ar-1) to (Ar-23), the formula (Ar-6) and the formula (Ar-7) are preferable from the viewpoint of molecular stability.

In the formulae (Ar-17) to (Ar-23), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom and Z ⁰ to which it is bonded.

As an aromatic heterocyclic group, the aromatic heterocyclic ring demonstrated above as an aromatic heterocyclic ring which Ar may have can be mentioned. A pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, a quinoline ring, an isoquinoline ring, a purine ring, a pyrrolidine ring, etc. are mentioned. The aromatic heterocyclic group may have a substituent. Y ¹ may form the aforementioned substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group together with the nitrogen atom and Z ⁰ to which it is bonded. Examples of the polycyclic aromatic heterocyclic group include a benzofuran ring, a benzothiazole ring, a benzoxazole ring, and the like. The compound represented by the aforementioned formula (II) can be produced, for example, by the method described in JP-A No. 2010-31223.

The content of the polymerizable liquid crystal compound (B) in the polymerizable liquid crystal composition (B) is, for example, 70 to 99.5 parts by mass, preferably 80 to 100 parts by mass of the solid content of the polymerizable liquid crystal composition (B). 99 parts by mass, more preferably 90 to 98 parts by mass. When content is in the said range, there exists a tendency for the orientation of a retardation film to improve.

Here, the solid content refers to the total amount of the remaining components after removing volatile components such as a solvent from the polymerizable liquid crystal composition (B).

The polymerizable liquid crystal composition (B) may contain a polymerization initiator for initiating a polymerization reaction of the polymerizable liquid crystal compound (B).

As the polymerization initiator, the same polymerization initiators as the polymerization initiators exemplified above as the polymerization initiators usable in the polymerizable liquid crystal composition (A) can be mentioned. The polymerizable liquid crystal composition (B) may contain, if necessary, a photosensitizer, a leveling agent, and additives exemplified as additives contained in the polymerizable liquid crystal composition (A). As a photosensitizer and a leveling agent, the thing similar to the thing exemplified above as a photosensitizer and a leveling agent contained in a polymerizable liquid crystal composition (A) is mentioned.

The retardation film can be obtained by adding a solvent to a polymerizable liquid crystal composition (B) containing a polymerizable liquid crystal compound (B) and, if necessary, a polymerization initiator, an additive, and the like, followed by mixing and stirring. A composition (hereinafter, also referred to as a "retardation film-forming composition") is applied to a substrate or an alignment film, the solvent is removed by drying, and the resulting coating film is polymerized by heating and/or active energy rays The liquid crystal compound (B) is cured. As the base material and/or the alignment film that can be used for the production of the retardation film, the base material and/or the above-exemplified base material and/or the alignment film that can be used in the production of the polarizing film of the present invention are exemplified above. Or the same substrate and/or alignment film as the alignment film.

Regarding the solvent used in the composition for forming a retardation film, the coating method of the composition for forming a retardation film, the curing conditions by active energy rays, etc., the same can be mentioned in the production method of the polarizing film of the present invention. The same example used.

The thickness of the retardation film can be appropriately selected according to the display device to be applied, but from the viewpoints of thinning and flexibility, etc., it is preferably 0.1 to 10 μm, more preferably 1 to 5 μm, and even more preferably 1 to 3 μm.

The polarizing plate of the present invention includes the polarizing film and retardation film of the present invention, and preferably includes a substrate, an alignment film (especially, a photo alignment film), and the polarizing film and retardation film of the present invention. The polarizing plate of the present invention may further contain other layers (protective layer, adhesive layer, etc.) other than these. In the polarizing plate of the present invention, the polarizing film and the retardation film of the present invention may be bonded together via an adhesive layer or an adhesive layer. In the polarizing plate of the present invention, the retardation film can be directly formed on the polarizing film of the present invention by directly applying the composition for forming a retardation film to the polarizing film of the present invention.

The thickness of the polarizing plate of the present invention is preferably 10 to 300 μm, more preferably 20 to 200 μm, and even more preferably 25 to 100 μm, from the viewpoints of flexibility and visibility of the display device.

The present invention includes a display device including the polarizing film of the present invention or the polarizing plate of the present invention.

The display device of the present invention can be obtained, for example, by bonding the polarizing film or polarizing plate of the present invention to the surface of the display device through an adhesive layer.

A display device refers to a device having a display mechanism, and includes a light-emitting element or a light-emitting device as a light-emitting source. Examples of display devices include liquid crystal display devices, organic electroluminescence (EL) display devices, inorganic electroluminescence (EL) display devices, touch panel display devices, electron emission display devices (field emission display devices (FED), surface Conductive field emission display (SED)), electronic paper (display using electronic ink, electrophoretic elements, plasma display, projection display (eg grating light valve (GLV) display, digital micromirror device ( DMD) display devices, etc.) and piezoelectric ceramic displays, etc. Liquid crystal display devices include transmissive liquid crystal display devices, semi-transmissive liquid crystal display devices, reflective liquid crystal display devices, direct-view liquid crystal display devices, and projection-type liquid crystal display devices, etc. All in. These display devices can be display devices that display two-dimensional images, and can also be stereoscopic display devices that display three-dimensional images. Especially, as a display device of the present invention, preferably an organic EL display device and a touch panel display device, especially An organic EL display device is preferred.

Example

<Preparation of a polymerizable liquid crystal composition (hereinafter, also referred to as a “composition for forming a polarizing film”)>

The following components were mixed and stirred at 80° C. for 1 hour to obtain a composition (1) for forming a polarizing film. As the dichroic dye, the azo dye described in the Examples of JP-A No. 2013-101328 was used. Hereinafter, unless otherwise stated, "%" and "parts" in the examples represent mass % and mass parts, respectively.

·Polymerizable liquid crystal compound:

[Chemical formula 24]

[Chemical formula 25]

·Dichroic pigments:

azo pigments;

[Chemical formula 26]

[Chemical formula 27]

[Chemical formula 28]

·Polymerization initiator:

2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by CibaSpecialty Chemicals, Inc.) 6 parts

·Leveling agent:

Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) 1.2 parts

·Solvent:

400 parts of o-xylene

In addition, the composition (1) for forming a polarizing film was carried out in the same manner as the composition (1) for forming a polarizing film, except that the compound described below as an antioxidant was mixed in the amount shown in Table 1, The polarizing film forming compositions (2) to (18) were obtained.

The addition amount of the antioxidant in Table 1 shows the amount with respect to 100 mass parts of polymerizable liquid crystal compounds in the composition for polarizing film formation.

＜Structure of antioxidants＞

The structures of the antioxidants used in Examples and Comparative Examples are as follows.

[Chemical formula 29]

(Antioxidant A: 4-n-Octyloxyphenol)

[Chemical formula 30]

(Antioxidant B: 4,4'-biphenol)

[Chemical formula 31]

(Antioxidant C: 4-ethoxy-4'-hydroxybiphenyl)

[Chemical formula 32]

(Antioxidant D: 4-butoxy-4'-hydroxybiphenyl)

[Chemical formula 33]

(Antioxidant E: 4-octyloxy-4'-hydroxybiphenyl)

[Chemical formula 34]

(Antioxidant F: Dibutylhydroxytoluene)

[Chemical formula 35]

(Antioxidant G: Tinuvin 770; manufactured by BASF Corporation)

[Chemical formula 36]

(Antioxidant H: Sumilizer GP; manufactured by Sumitomo Chemical Co., Ltd.) [Chemical formula 37]

(Antioxidant I: p-methoxyphenol)

【Table 1】

<Measurement of liquid crystal phase transition temperature change T1-T2>

(1) Formation of alignment film

A 2 mass % aqueous solution of polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified type, manufactured by Wako Pure Chemical Industries, Ltd.) was applied on a glass substrate by spin coating, and dried to form a film having a thickness of 100 nm. Next, an alignment film is formed by subjecting the surface of the obtained film to a rubbing treatment. For friction treatment, a semi-automatic friction device (trade name: LQ-008, manufactured by Changyang Kogaku Co., Ltd.) was used, and a cloth (trade name: YA-20-RW, manufactured by Yoshikawa Chemical Co., Ltd.) was used. The rotation speed was 500 rpm and 16.7 mm/s.

(2) Determination of T1

As a polymerizable liquid crystal compound, 90 parts of the compound represented by the formula (A-6), 10 parts of the compound represented by the formula (A-7), and 400 parts of o-xylene were stirred at 80° C. for 1 hour to obtain a uniform Mixed mixed composition.

The obtained mixed composition was applied on the glass with the aforementioned alignment film by spin coating, and heated and dried on a hot plate at 130° C. for 3 minutes, thereby removing o-xylene as a solvent. Then, the obtained coating film was rapidly cooled to room temperature to obtain a dry film of the polymerizable liquid crystal compound. The temperature of the dry film was again raised to 130°C on a hot plate, and then, when the temperature was lowered to 23°C at a rate of 5°C/min, the phase transition temperature was measured by observing with a polarizing microscope. As a result, it was confirmed that the phase changed to a nematic liquid crystal phase at 113.7°C, a smectic A phase at 109.6°C, a smectic B phase at 92.0°C, and the smectic B phase was maintained until it reached 23°C. In the above-mentioned process, the liquid crystal phase exhibited on the lowest temperature side is the smectic B phase, and therefore, T1 is defined as the phase transition temperature of 92.0° C. for the transition to the smectic B phase.

(3) Determination of T2

The measurement of T1 in the above (2) was exactly the same as the measurement of T1 in the above-mentioned (2) except that 1 part by mass of each of the antioxidants A to I was added to 100 parts by mass of the polymerizable liquid crystal compound to the above-mentioned mixed composition In this method, a dry film formed of a mixture of an antioxidant and a polymerizable liquid crystal compound is obtained. The phase transition temperature was measured by the same method as the measurement of T1 in the above (2). As a result, in all the mixtures, the liquid crystal phase exhibited on the lowest temperature side was the smectic B phase. Table 2 describes the phase transition temperature (T2) of the liquid crystal phase transition to the lowest temperature side when each antioxidant is contained.

【Table 2】

Example 1

(1) Preparation of photo-alignment film on substrate

(i) Preparation of the composition for forming a photo-alignment film

The following components described in Unexamined-Japanese-Patent No. 2013-033249 were mixed, and the obtained mixture was stirred at 80 degreeC for 1 hour, and the composition for photo-alignment film formation was obtained by this.

·Photo-orientable polymer:

[Chemical formula 38]

·Solvent:

98 parts of o-xylene

(ii) Formation of photo-alignment film

A triacetyl cellulose film (KC8UX2M, manufactured by Konica Minolta Co., Ltd.) was used as a base material, and after corona treatment was performed on the film surface, the above-mentioned composition for forming a photo-alignment film was applied and dried at 120° C. to obtain a dried film. The polarized UV light was irradiated on this dry film, and a photo-alignment film was formed, and the film with a photo-alignment film was obtained. The polarized UV light treatment was performed using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Inc.) under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ.

(2) Production of polarizing film

On the film with the photo-alignment film obtained as described above, the composition (2) for forming a polarizing film was applied by a bar coating method (#9, 30 mm/s), and the composition was applied in a drying oven at 120°C. The polymerizable liquid crystal compound was changed into a liquid phase by heating and drying for 1 minute, and then, the polymerizable liquid crystal compound was cooled to room temperature to change the phase of the polymerizable liquid crystal compound into a smectic liquid crystal state. Next, using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Inc.), the layer formed of the polarizing film-forming composition was irradiated with ultraviolet rays having an exposure amount of 1000 mJ/cm ² (365 nm reference), thereby causing the The polymerizable liquid crystal compound contained in the dry film is polymerized while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and a polarizing film is formed from the dry film. The film thickness of the polarizing film at this time was measured with a laser microscope (OLS3000, manufactured by Olympus Corporation) and found to be 2.3 μm. The product obtained as described above is a polarizer comprising a polarizing film and a substrate.

确认到形成了反映高阶近晶相的结构。About this polarizing film, X-ray diffraction measurement was carried out in the same manner using an X-ray diffractometer X'Pert PRO MPD (manufactured by Spectris Co., Ltd.), and as a result, it was obtained that the width at half maximum (FWHM)=about 2θ=20.2°. Sharp diffraction peak (Bragg peak) at 0.17°. In addition, equivalent results were obtained even with incidence from the rubbing perpendicular direction. The ordered period (d) obtained from the peak position is approximately

It was confirmed that a structure reflecting a higher-order smectic phase was formed.

(3) Production of polarizing film laminate

Furthermore, corona treatment was performed on the surface of the polarizing film of the polarizer obtained above, and the corona treated surface was coated with 100 parts of water by adding a carboxyl group modified by a wire bar coater (#30). Polyvinyl alcohol ["Kuraray POVAL KL318" manufactured by KURARAY Co., Ltd.] 7 parts, and a water-soluble polyamide epoxy resin as a thermal crosslinking agent ["Sumirez Resin 650" obtained from SumikaChemtex Co., Ltd. (solid content concentration) Aqueous solution (viscosity: 92 cP) of 3.5 parts of 30 mass % aqueous solution)]. The said aqueous solution was dried by drying at 80 degreeC for 5 minutes, a protective layer was formed, and the polarizer with a protective layer was manufactured. Further, on the protective layer, glass (EagleXG, manufactured by Corning Inc.) was bonded via an adhesive layer formed of a pressure-sensitive adhesive (manufactured by Lintec Corporation, with a film thickness of 25 μm) to obtain the polarized light of Example 1. film stack.

<Measurement of Polarization Degree Py and Monomer Transmittance Ty>

The degree of polarization Py and the single transmittance Ty of the polarizing film laminate of Example 1 were measured as follows. Using a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation) equipped with a folder with a polarizer, transmittance was measured in the wavelength range of 380 nm to 780 nm by the double beam method. Transmittance in the axial direction (Ta) and transmittance in the absorption axis direction (Tb). On the reference side of the folder, a mesh that blocks 50% of the light is placed.

Using the following equations (Equation 1) and (Equation 2), the individual transmittance and polarization degree at each wavelength were calculated, and further, the visibility correction was performed according to the 2-degree field of view (C light source) of JISZ 8701, and the visibility correction was calculated. Monomer transmittance (Ty) and visibility correction polarization (Py).

Monomer transmittance Ty(%)=(Ta+Tb)/2 (Formula 1)

Polarization degree Py(%)=(Ta-Tb)/(Ta+Tb)×100 (Formula 2)

Example 2 was obtained by the same method except that the polarizing film forming compositions (1), (3) to (18) shown in Table 3 were used instead of the polarizing film forming composition (2), respectively. ~15. The polarizing film laminates of Comparative Example 1, Comparative Example 2, and Reference Example 1.

<Evaluation of light resistance>

About the laminated bodies of Examples 1-15, the comparative example 1, the comparative example 2, and the reference example 1, the light resistance was evaluated by the following method. The results are shown in Table 3.

The above-mentioned polarizing film laminate was put into a light resistance tester (SUNTEST XLS+; manufactured by ATLAS) with the triacetyl cellulose film as the base material facing upward, and the test was carried out under the condition of a cumulative light amount of 23070 KJ/m ² After the light irradiation, the degree of polarization Py and the single transmittance Ty of the laminate were measured again, and the amount of change rate before and after the light resistance test was calculated.

[table 3]

It was confirmed that the polarizing films (Examples 1 to 15) produced from the polarizing film-forming compositions 2 to 16, that is, the polymerizable liquid crystal compositions of the present invention, have good light resistance.

Example 16

＜Production of circular polarizer＞

The retardation film produced according to Example 1 of JP-A No. 2015-143786 was transferred to the polarized light of Example 5 through an adhesive layer formed of a pressure-sensitive adhesive (manufactured by Lintec Corporation, film thickness: 25 μm). On the protective layer of the polarizer with a protective layer obtained during the production of the film laminate. Next, an aluminum metal plate was bonded via an adhesive layer formed of a pressure-sensitive adhesive (manufactured by Lintec Corporation, film thickness: 25 μm) to obtain an elliptically polarizing plate.

<Measurement of reflected hue a*, b*>

The L*a*b* (CIE) color was measured using a spectrophotometer (CM-3700d, manufactured by Konica Minolta Co., Ltd.) for the reflection hue of the triacetyl cellulose film surface as the base material of the obtained elliptically polarizing plate. Chromaticity a* and b* in the system.

<Evaluation of light resistance>

Next, the surface of the triacetyl cellulose film as the base material was turned up, put into a light resistance tester (SUNTESTXLS+; manufactured by ATLAS), irradiated with light under the condition of a cumulative light amount of 23070 KJ/m ² , and then measured again. The chromaticity a* and b* of the laminate were calculated as the amount of change before and after the light resistance test. The results are shown in Table 4.

[Table 4]

It was confirmed that the elliptically polarizing plate provided with the polarizing film of the present invention has a small amount of change in chromaticity and good light resistance.

Claims (15)

1. A polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound having at least 1 polymerizable group and exhibiting smectic liquid crystallinity, a dichroic dye, and an antioxidant, wherein,

the polymerizable group of the polymerizable liquid crystal compound is a radical polymerizable group,

the relationship between the antioxidant and the polymerizable liquid crystal compound satisfies formula (1):

0.8℃≤T1-T2 (1)

wherein T1 is a phase transition temperature at which the polymerizable liquid crystal compound is brought to 130 ℃ in the atmosphere and the phase transition temperature is measured while cooling to 23 ℃ at 5 ℃/min, and T2 is a phase transition temperature at which the polymerizable liquid crystal compound is brought to the lowest temperature when a mixture of 100 parts by mass of the polymerizable liquid crystal compound and 1 part by mass of the antioxidant is brought to 130 ℃ in the atmosphere and the phase transition temperature is measured while cooling to 23 ℃ at 5 ℃/min.

2. The polymerizable liquid crystal composition of claim 1, further comprising a solvent.

3. The polymerizable liquid crystal composition according to claim 1 or 2, wherein the dichroic pigment is an azo pigment.

4. The polymerizable liquid crystal composition according to any one of claims 1 to 3, wherein the polymerizable group of the polymerizable liquid crystal compound is an acryloyloxy group.

5. The polymerizable liquid crystal composition according to any one of claims 1 to 4, wherein the antioxidant is contained in an amount of 0.1 to 15 parts by mass per 100 parts by mass of the polymerizable liquid crystal compound.

6. The polymerizable liquid crystal composition according to any one of claims 1 to 5, wherein the antioxidant is at least 1 selected from the group consisting of a phenol compound, an alicyclic alcohol compound and an amine compound.

7. The polymerizable liquid crystal composition according to any one of claims 1 to 6, wherein the antioxidant has any structure represented by the formulae (2), (3) and (4),

[ chemical formula 1]

In the formulae (2) and (3), R₁～R₅Each independently is-H, -OH, -NH₂A branched or unbranched alkyl group having 1 to 12 carbon atoms or a branched or unbranched alkoxy group having 1 to 12 carbon atoms, wherein in the formulae (2) and (3), R is independently₁～R₅At least 1 of which is-OH or-NH₂。

8. The polymerizable liquid crystal composition according to claim 7, wherein the antioxidant is a compound represented by the formula (5),

A₁-L₁-(A₂-L₂)_n-A₃(5)

in the formula (I), the compound is shown in the specification,

L₁and L₂Each independently is a single bond or a divalent linking group;

A₁is a group represented by the formula (2), (3) or (4),

[ chemical formula 2]

In the formulae (2) and (3), R₁～R₅The same definition as that described in claim 7;

A₂is a group represented by the formula (6) or (7),

[ chemical formula 3]

In the formulae (6) and (7), R₆～R₉Each independently is-H, -OH, -NH₂A branched or unbranched alkyl group having 1 to 12 carbon atoms, or a branched or unbranched alkoxy group having 1 to 12 carbon atoms;

A₃is a group represented by the formula (8) or (9),

[ chemical formula 4]

In the formulae (8) and (9), R₁₀～R₁₄Each independently is-H, -OH, -NH₂A branched or unbranched alkyl group having 1 to 12 carbon atoms, or a branched or unbranched alkoxy group having 1 to 12 carbon atoms;

n is an integer of 0 to 2, and when n is 2, 2A₂May be the same or different from each other.

9. A polarizing film which is a cured product of a polymerizable liquid crystal composition comprising a dichroic dye, a polymerizable liquid crystal compound and an antioxidant,

the polarizing film showed a Bragg peak in X-ray diffraction measurement,

the relationship between the antioxidant and the polymerizable liquid crystal compound satisfies formula (1):

0.8℃≤T1-T2 (1)

wherein T1 is a phase transition temperature at which the polymerizable liquid crystal compound is brought to 130 ℃ in the atmosphere and the phase transition temperature is measured while cooling to 23 ℃ at 5 ℃/min, and T2 is a phase transition temperature at which the polymerizable liquid crystal compound is brought to the lowest temperature when a mixture of 100 parts by mass of the polymerizable liquid crystal compound and 1 part by mass of the antioxidant is brought to 130 ℃ in the atmosphere and the phase transition temperature is measured while cooling to 23 ℃ at 5 ℃/min.

10. A polarizing plate comprising the polarizing film according to claim 9 and a retardation film.

11. The polarizing plate of claim 10, wherein the retardation film satisfies formula (X):

100≤Re(550)≤180 (X)

wherein Re (550) represents an in-plane retardation value at a wavelength of 550nm,

an angle formed by the slow axis of the phase difference film and the absorption axis of the polarizing film is substantially 45 °.

12. The polarizing plate of claim 10 or 11, wherein the retardation film satisfies formula (Y):

Re(450)/Re(550)＜1 (Y)

wherein Re (450) and Re (550) represent in-plane retardation values at wavelengths of 450nm and 550nm, respectively.

13. The polarizing plate according to any one of claims 10 to 12, wherein the retardation film is composed of a polymer in an aligned state of a polymerizable liquid crystal compound.

14. A display device comprising the polarizing film according to claim 9 or the polarizing plate according to any one of claims 10 to 13.

15. A method for producing a polarizing film, comprising the steps of:

a step of forming a coating film of the polymerizable liquid crystal composition according to any one of claims 1 to 8;

a step of removing the solvent from the coating film;

a step of decreasing the temperature after increasing the temperature to a temperature at which the polymerizable liquid crystal compound changes phase into liquid phase or higher to change the polymerizable liquid crystal compound into a smectic phase; and

and polymerizing the polymerizable liquid crystal compound while maintaining the smectic phase.