JPWO2014109371A1 - Photopolymerizable liquid crystal composition, optical compensation film, optical compensation laminated film, electrode substrate, substrate for liquid crystal display device and liquid crystal display device - Google Patents

Abstract

Photopolymerizable liquid crystal composition capable of forming a positive A plate having improved birefringence wavelength dispersion characteristics and good heat resistance for the manufacturing process of a liquid crystal display device, optical compensation film and optical compensation laminate using the same Providing films, electrode substrates, substrates for liquid crystal display devices, and liquid crystal display devices. For forming an optical compensation film exhibiting positive uniaxial anisotropy, a first photopolymerizable liquid crystal (A) having an aliphatic ring and no aromatic ring, and a second having an aromatic ring The amount of the first photopolymerizable liquid crystal (A) is 50% by mass or more and less than 100% by mass with respect to the total amount of the photopolymerizable liquid crystal. A photopolymerizable liquid crystal composition, wherein the amount of the polymerizable liquid crystal (B) is more than 0% by mass and 50% by mass or less. The optical compensation laminated film 12 includes an optical compensation film 12A exhibiting negative uniaxial anisotropy and an optical compensation film 12B exhibiting positive uniaxial anisotropy manufactured using the above composition.

Description

  The present invention relates to a photopolymerizable liquid crystal composition, and an optical compensation film, an optical compensation laminated film, an electrode substrate, a liquid crystal display substrate, and a liquid crystal display device using the photopolymerizable liquid crystal composition.

In a liquid crystal display device, an optical compensation film (also referred to as a retardation film) that has birefringence and controls the phase of light is used to increase the viewing angle. In particular, a liquid crystal display device in a vertical alignment (hereinafter sometimes abbreviated as “VA”) mode tends to have a narrow viewing angle, and an optical compensation film is an essential component. Patent Document 5 and the like disclose that in a VA mode liquid crystal display device, a positive A plate is used as phase difference compensation to suppress light leakage when a viewing angle increases.
Conventionally, the optical compensation film and the polarizing film are externally attached to the liquid crystal cell, and the thickness of the optical compensation film is about 50 to 150 μm.
On the other hand, in recent years, an optical compensation laminated film is provided inside a liquid crystal cell to reduce the thickness of a liquid crystal display device and an electronic device on which the liquid crystal display device is mounted.

Examples of the form of the optical compensation laminated film include the following optical compensation laminated films (i) to (iv).
(I) An optical compensation laminated film in which a biaxial plate is laminated on an alignment film such as polyimide.
(Ii) On an alignment film such as polyimide, an optical compensation film exhibiting positive uniaxial anisotropy (hereinafter also referred to as positive A plate) and an optical compensation film exhibiting negative uniaxial anisotropy (hereinafter also referred to as negative C plate) And an optical compensation laminated film sequentially laminated.
(Iii) An optical compensation laminated film in which a positive A plate is laminated on a negative C plate through an alignment film.
(Iv) An optical compensation laminated film in which a positive A plate is directly laminated on a negative C plate that functions as an alignment film.

  Patent Documents 1 and 2 disclose a liquid crystal display substrate provided with the optical compensation laminated film (iii) or (iv).

In Examples 1 and 2 of Patent Document 1, polyester is applied on a substrate, and the obtained coating film is heat-dried and baked, and then rubbed to perform a function as an alignment film. A negative C plate is formed. Thereafter, a photopolymerizable liquid crystal is applied on the negative C plate, dried by heating, and then photopolymerized to form a positive A plate (paragraphs 0025 and 0026).
In Examples 1 and 2 of Patent Document 1, only one type of photopolymerizable liquid crystal having an aromatic ring is used as the photopolymerizable liquid crystal of the positive A plate material.

In Example 8 of Patent Document 2, polyimide is applied on a substrate, and the obtained coating film is dried by heating and baking to form a negative C plate. An alignment film is formed on the negative C plate, a rubbing treatment is performed, a photopolymerizable liquid crystal is applied, dried, and then photopolymerized to form a positive A plate (paragraphs 0098 to 0098). 0100).
In each of Examples 1 to 12 of Patent Document 2, only one type of photopolymerizable liquid crystal having an aromatic ring is used as the photopolymerizable liquid crystal of the positive A plate material.

JP 2010-230823 A JP 2009-223304 A International Publication No. 2009/148142 International Publication No. 2011/004826 Japanese Patent Laid-Open No. 11-258605

  For a positive A plate for a color liquid crystal display device, the wavelength dispersion of retardation Re as shown by image curve I in FIG. 5 is required. However, in the conventional positive A plate, as in Patent Documents 1 and 2, conventionally, a photopolymerizable liquid crystal having an aromatic ring is used, and the expected wavelength dispersion is obtained by the light absorption of the aromatic ring. It is difficult. Specifically, in a conventional positive A plate using a photopolymerizable liquid crystal having an aromatic ring, Re becomes smaller as the wavelength becomes longer, as shown by an image curve II in FIG. Note that Re is an index of birefringence in the xy plane, the definition of which will be described later.

  Therefore, the positive A plate is designed for phase difference compensation around a specific wavelength, specifically, green light having the highest visibility. Since the conventional positive A plate shows the chromatic dispersion of the image curve II in FIG. 5, the leakage of red and blue light components cannot be sufficiently reduced in black display when the viewing angle is increased.

Patent Documents 3 and 4 disclose photopolymerizable liquid crystals having an aliphatic ring and no aromatic ring (see Claim 1 of Patent Document 3 and Claim 1 of Patent Document 4). .
The above-mentioned patent document is mainly directed to the use of an optical information recording / reproducing apparatus, and does not describe application to an optical compensation film inside a liquid crystal cell. However, any of the above materials has a positive value of Δn (see Table 2 of Patent Document 3 and Table 2 of Patent Document 4), and can be used as a positive A plate material. Here, Δn is refractive index anisotropy.
It is considered that the wavelength dispersion characteristics of Re can be improved in a positive A plate using a photopolymerizable liquid crystal having no aromatic ring.
When an optical compensation film is provided inside a liquid crystal cell, heat resistance that does not change the optical characteristics of the optical compensation film is required for the manufacturing process after film formation. However, the photopolymerizable liquid crystal having no aromatic ring described in Patent Documents 3 and 4 is inferior in heat resistance to the photopolymerizable liquid crystal having an aromatic ring.

An object of the present invention is to provide a photopolymerizable liquid crystal composition capable of forming a positive A plate having improved birefringence wavelength dispersion characteristics and having good heat resistance for a manufacturing process of a liquid crystal display device.
“Improving the birefringence wavelength dispersion characteristic” means that the birefringence wavelength dispersion characteristic becomes ideal for a liquid crystal display device.
An object of the present invention is to provide an optical compensation film comprising a positive A plate having improved birefringence wavelength dispersion characteristics and good heat resistance for a manufacturing process of a liquid crystal display device.
An object of the present invention is to provide an optical compensation laminated film that includes a negative C plate and a positive A plate, has improved birefringence wavelength dispersion characteristics, and has good heat resistance for a manufacturing process of a liquid crystal display device. To do.
An object of the present invention is to provide an electrode substrate, a substrate for a liquid crystal display device, and a liquid crystal display device that have favorable optical characteristics and can be reduced in thickness and cost.

  The present invention provides a photopolymerizable liquid crystal composition, an optical compensation film, an optical compensation laminated film, an electrode substrate, a substrate for a liquid crystal display device and a liquid crystal display device having the following configurations [1] to [15].

The inventor uses the first photopolymerizable liquid crystal (A) having an aliphatic ring and not having an aromatic ring in combination with the second photopolymerizable liquid crystal (B) having an aromatic ring. Thus, it has been found that the wavelength dispersion characteristics of birefringence can be improved and a positive A plate having good heat resistance for the manufacturing process of the liquid crystal display device can be formed.
[1] A photopolymerizable liquid crystal composition for forming an optical compensation film exhibiting positive uniaxial anisotropy,
A first photopolymerizable liquid crystal (A) having an aliphatic ring and no aromatic ring;
A second photopolymerizable liquid crystal (B) having an aromatic ring,
The amount of the first photopolymerizable liquid crystal (A) is 50% by mass or more and less than 100% by mass, and the amount of the second photopolymerizable liquid crystal (B) is 0% by mass with respect to the total amount of the photopolymerizable liquid crystal. A photopolymerizable liquid crystal composition having an ultra-50% by mass or less.

[2] The first photopolymerizable liquid crystal (A) includes a monofunctional photopolymerizable liquid crystal containing one photopolymerizable reactive group in one molecule and / or two photopolymerizable reactive groups in one molecule. [1] The photopolymerizable liquid crystal composition according to [1], including a bimonofunctional photopolymerizable liquid crystal.

[3] The photopolymerizable liquid crystal composition according to [2], wherein the first photopolymerizable liquid crystal (A) includes a monofunctional photopolymerizable liquid crystal represented by the following formula (11).
_{^{CH 2 = CR 11 -COO- (L}} 1) a1 -E 11 - (S 1) b1 -E 12 - (T 1) c1 - (E 13) d1 -R 12 ··· (11)
(However, the symbols in the formulas have the following meanings: R ¹¹ : hydrogen atom or methyl group. R ¹² : an alkyl group or fluorine atom having 1 to 8 carbon atoms (in the case of an alkyl group, between carbon-carbon bonds) Alternatively, it may have an etheric oxygen atom at the terminal bonded to the ring group, and part or all of the hydrogen atoms may be substituted with fluorine atoms.) L ¹ : Between carbon-carbon bond May have an etheric oxygen atom, a part or all of the hydrogen atoms may be substituted with fluorine atoms, and COO, OCO or O may be present at the bonding position with E ^11. Or an alkyl group having 1 to 8 carbon atoms E ¹¹ , E ¹² and E ¹³ : each independently a trans-1,4-cyclohexylene group or a trans-2,6-decahydronaphthalene group (provided that Charcoal .. The hydrogen atoms bonded to atoms may be substituted by fluorine atom or a methyl group) ^{S 1} and ^{T 1:} independently, -OCO -, - COO -, - (CH 2) 2 -, - CH ₂ O—, —OCH ₂ — or a single bond, a1, b1, c1 and d1: each independently 0 or 1.)

[4] The photopolymerizable liquid crystal composition according to [2], wherein the first photopolymerizable liquid crystal (A) includes a bifunctional photopolymerizable liquid crystal represented by the following formula (12).
_{^{CH 2 = CR 21 -COO- (L}} 2) a2 -E 21 - (S 2) b2 -E 22 - (T 2) c2 - (E 23) d2 - (M 2) e2 -OCO-CR 22 = CH ₂ ... (12)
(However, the symbols in the formulas have the following meanings: R ²¹ and R ²² : each independently a hydrogen atom or a methyl group. L ² : even if it has an etheric oxygen atom between carbon-carbon bonds. An alkyl group having 1 to 8 carbon atoms, in which part or all of the hydrogen atoms may be substituted with fluorine atoms, and may have COO, OCO or O at the position where E ²¹ is bonded. ^2: carbon - may have an etheric oxygen atom between carbon bonds, some or all of the hydrogen atoms may be substituted by fluorine atoms, COO a position to bind to the E ^23, C 1-8 alkyl group which may have OCO or O. E ²¹ , E ²² and E ²³ : each independently a trans-1,4-cyclohexylene group or trans-2,6-decahydro Naphthalene group However, the hydrogen atoms bonded to carbon atoms in the group may be substituted by a fluorine atom or a methyl group) ^{S 2} and ^{T 2:..} Each independently, -OCO -, - COO -, - (CH 2 ) _2- , -CH ₂ O-, -OCH ₂ -or a single bond, a2, b2, c2, d2 and e2: each independently 0 or 1.)

[5] The photopolymerizable liquid crystal composition according to any one of [1] to [4], wherein the second photopolymerizable liquid crystal (B) is represented by the following formula (20).
^{Q 1 -Z 1 -A 1 -Z 3} -M-Z 4 -A 2 -Z 2 -Q 2 ··· (20)
(However, the symbols in the formulas have the following meanings: Q ¹ and Q ² : each independently a photopolymerizable group. Z ¹ , Z ² , Z ³ and Z ⁴ : each independently a single bond or a divalent group. Linking group A ¹ and A ² : each independently a spacer group having 2 to 20 carbon atoms M: a mesogenic group containing an aromatic ring)

[6] The photopolymerizable liquid crystal composition according to [5], wherein the second photopolymerizable liquid crystal (B) includes a photopolymerizable liquid crystal represented by the following formula (21).
^{_{CH 2 = CR 41 -COO- (E}} 41) m4 -Cy-Y 4 -Cy- (E 42) n4 -OCO-CR 42 = CH 2 ··· (21)
(However, the symbols in the formula have the following meanings: R ⁴¹ and R ⁴² : each independently a hydrogen atom or a methyl group. Y ⁴ : —OCO— or —COO—. M4 and n4: each independently 0 or 1 (Except when both are 0) E ⁴¹ and E ⁴² : each independently 1,4-phenylene group or trans-1,4-cyclohexylene group, provided that at least one of E ⁴¹ and E ⁴² is 1,4-phenylene group, Cy: trans-1,4-cyclohexylene group, where the 1,4-phenylene group and trans-1,4-cyclohexylene group are such that the hydrogen atom in the group is a fluorine atom , May be substituted with a chlorine atom or a methyl group.)

[7] The photopolymerizable liquid crystal composition according to [5], wherein the second photopolymerizable liquid crystal (B) includes a photopolymerizable liquid crystal represented by the following formula (22).
_{^{CH 2 = CR 51 -COO- (L}} 5) k5 -E 51 -E 52 -E 53 -E 54 - (M 5) n5 -OCO-CR 52 = CH 2 ··· (22)
(However, the symbols in the formula have the following meanings: R ⁵¹ and R ⁵² : each independently a hydrogen atom or a methyl group. K5 and n5: each independently 0 or 1. L ⁵ :-(CH ₂ ) _p5 O — Or — (CH ₂ ) _p5 — (where p5 is an integer of 2 to 8.) M ⁵ : —O (CH ₂ ) _p5 — or — (CH ₂ ) _p5 — (where p5 is 2 to 2) E ⁵¹ : 1,4-phenylene group E ⁵² , E ⁵³ and E ⁵⁴ : each independently 1,4-phenylene group or trans-1,4-cyclohexylene group, and E ⁵² And at least one of E ⁵³ is a trans-1,4-cyclohexylene group, provided that the 1,4-phenylene group and the trans-1,4-cyclohexylene group are hydrogen atoms bonded to carbon atoms in the group. Is a fluorine atom, salt (It may be substituted with an elementary atom or a methyl group.)

[8] The photopolymerizable liquid crystal composition according to [5], wherein the second photopolymerizable liquid crystal (B) includes a photopolymerizable liquid crystal represented by the following formula (23).
_{^{CH 2 = CR 61 -COO- (L}} 6) k6 -E 61 -E 62 -E 63 - (M 6) n6 -OCO-CR 62 = CH 2 ··· (23)
(However, the symbols in the formulas have the following meanings: R ⁶¹ and R ⁶² : each independently a hydrogen atom or a methyl group. K6 and n6: each independently 0 or 1. L ⁶ :-(CH ₂ ) _p6 O -, - Cy-COO- (Cy is a trans-1,4-cyclohexylene group.) (wherein, p6 2-8 ^integer.), or -Cy-OCO- M 6:. -O (CH 2 ^{_{) p6 -, -...}} OCO-Cy- (Cy here trans-1,4-cyclohexylene group), or -COO-Cy- (, p6 2-8 ^integer) E ^{61, E 62} and E ⁶³ : each independently a 1,4-phenylene group or a trans-1,4-cyclohexylene group, provided that at least one of E ⁶¹ , E ⁶² and E ⁶³ is a 1,4-phenylene group; At least 1 . Is trans-1,4-cyclohexylene group also, ^{E 61} when ^{L 6} is -Cy-OCO- is trans-1,4-cyclohexylene group, ^{L 6} is - _(CH 2) Each of E ⁶¹ and E ⁶³ when _p6 O- or k6 is 0 is a 1,4-phenylene group, and E ⁶² is a trans-1,4-cyclohexylene group). However, in the 1,4-phenylene group and trans-1,4-cyclohexylene group, a hydrogen atom bonded to a carbon atom in the group may be substituted with a fluorine atom, a chlorine atom or a methyl group. )

[9] The photopolymerizable liquid crystal composition according to [5], wherein the second photopolymerizable liquid crystal (B) includes a photopolymerizable liquid crystal represented by the following formula (24).
_{^{CH 2 = CR 71 -COO- (L}} 7) k7 -Ph- (X 7) -Ph- (Y 7) -Ph- (M 7) n7 -OCO-CR 72 = CH 2 ··· (24)
(However, the symbols in the formula have the following meanings: R ⁷¹ and R ⁷² : each independently a hydrogen atom or methyl group. X ⁷ and Y ⁷ : each independently -OCO- or -COO-. L ⁷ :- _{(CH 2) p7 O -,} - (CH 2) p7 O-COO -, - (CH 2) p7 OCO- or _{- (CH} 2) p7 COO- (wherein, p7 2-8 integer.). M ⁷ : —O (CH ₂ ) _{p 7} —, OCO—O (CH ₂ ) _{p 7} —, —OCO— (CH ₂ ) _{p 7} or —COO (CH ₂ ) _{p 7} — (where p 7 is an integer of 2 to 8) K7 and n7: each independently 0 or 1. Ph: 1,4-phenylene group, where the hydrogen atom bonded to the carbon atom in the group is a fluorine atom or a chlorine atom. Or substituted with a methyl group It has.)

[10] An optical compensation film having positive uniaxial anisotropy, comprising the photopolymerizable liquid crystal composition according to any one of [1] to [9].
[11] An optical compensation laminated film having an optical compensation film exhibiting negative uniaxial anisotropy and an optical compensation film exhibiting positive uniaxial anisotropy of [10] laminated on the optical compensation film.
[12] The optical compensation laminated film according to [11], wherein the optical compensation film exhibiting negative uniaxial anisotropy includes a polyimide having an aliphatic ring in the skeleton.

[13] An electrode substrate having the optical compensation laminated film of [12] and an electrode formed on the optical compensation laminated film on a substrate.
[14] A substrate for a liquid crystal display device, comprising the electrode substrate according to [13] and an alignment film formed on the electrode substrate.
[15] A liquid crystal display device comprising the liquid crystal substrate according to [14], a counter substrate, and a liquid crystal layer sandwiched between the liquid crystal substrate and the counter substrate.

The photopolymerizable liquid crystal composition of the present invention can form a positive A plate having improved birefringence wavelength dispersion characteristics and good heat resistance for the manufacturing process of a liquid crystal display device.
The optical compensation film comprising the positive A plate of the present invention has improved birefringence wavelength dispersion characteristics and has good heat resistance to the manufacturing process of the liquid crystal display device.
The optical compensation laminated film of the present invention includes a negative C plate and a positive A plate, has improved birefringence wavelength dispersion characteristics, and has good heat resistance for the manufacturing process of a liquid crystal display device.
The electrode substrate, the substrate for a liquid crystal display device and the liquid crystal display device of the present invention provided with the optical compensation laminated film have good optical characteristics. Since the electrode substrate, the substrate for a liquid crystal display device, and the liquid crystal display device of the present invention include the optical compensation laminated film in the liquid crystal cell, the thickness and cost can be reduced.

1 is an exploded schematic cross-sectional view of a liquid crystal display device according to an embodiment of the present invention. It is an exploded model sectional view showing an example of a design change. It is a schematic cross section which shows the structure of the optical compensation laminated film of one Embodiment which concerns on this invention. 22 is a graph showing the relationship between the measurement wavelength (nm) and Re of the optical compensation laminated film obtained in Example 21. 22 is a graph showing the relationship between the measurement wavelength (nm) and Re of the optical compensation laminated film obtained in Example 22. 14 is a graph showing the relationship between the measurement wavelength (nm) of the optical compensation laminated film obtained in Example 23 and Re. 25 is a graph showing the relationship between the measurement wavelength (nm) and Re of the optical compensation laminated film obtained in Example 24. It is an image graph which shows the relationship between the ideal in a positive A plate, the conventional wavelength (nm), and Re.

In the present specification, the group represented by the formula (x) may be simply referred to as a group (x).
In the present specification, the compound represented by the formula (y) may be simply referred to as the compound (y).
Here, the expressions (x) and (y) indicate arbitrary expressions.

In this specification, the plane parallel to the film surface of the optical compensation film (same for the optical compensation laminated film) is the xy plane, the film thickness direction is the z direction, and the refractive indices in the x direction, y direction, and z direction are Let nx, ny, and nz respectively.
As a material for the optical compensation film, a photopolymerizable liquid crystal having a rod-like molecular structure having linearity is used. In the optical compensation film, the rod-like molecule is in a state where the major axis direction is parallel to or close to the film surface. The x-axis direction is the major axis direction of the rod-like molecule.
In the negative C plate, nx = ny> nz.
For positive A plates, nx> ny = nz.
A retardation Rth that is an index of birefringence in the z direction in the negative C plate and a retardation Re that is an index of birefringence in the xy plane in the positive A plate are defined by the following equations.
Rth = P × da
(Here, da is the thickness of the negative C plate, and P = ((nx + ny) / 2−nz).)
Re = Δn × db
(Here, Δn is refractive index anisotropy and Δn = nx−ny. Db is the thickness of the positive A plate.)

Embodiments of the present invention will be described below.
Unless otherwise specified in the present specification, “%” represents mass%.

[Photopolymerizable liquid crystal composition]
The photopolymerizable liquid crystal composition of the present invention (hereinafter sometimes referred to as composition (Y)) is a material for forming an optical compensation film (positive A plate) exhibiting positive uniaxial anisotropy.
The composition (Y) comprises an aliphatic ring, a first photopolymerizable liquid crystal (A) having no aromatic ring, and a second photopolymerizable liquid crystal (B) having an aromatic ring. Including.

  The photopolymerizable liquid crystal composition of the present invention has an optical compensation film (positive A plate) exhibiting positive uniaxial anisotropy on an optical compensation film (negative C plate) exhibiting negative uniaxial anisotropy that functions as an alignment film. Can be preferably applied to an optical compensation laminated film in which is laminated.

The aromatic ring has light absorption, and the light absorption depends on the wavelength. Therefore, in the conventional positive A plate using only the second photopolymerizable liquid crystal (B) having an aromatic ring, the wavelength becomes longer as shown in the image curve II of FIG. As the value of Re decreases.
The wavelength dispersion of the retardation Re can be evaluated by, for example, the ratio of the retardation Re of green light and red light when the retardation Re at a certain arbitrary wavelength λ is Re (λ). That is, Re (450) / Re (590) <1 in an ideal positive A plate, but Re (450) / Re (590)> 1 when a conventional material is used.
By using the first photopolymerizable liquid crystal (A) having no aromatic ring, the wavelength dispersion characteristics of Re can be improved, and Re (450) / Re (590) can be reduced. However, materials that do not have an aromatic ring tend to be less heat resistant than materials that have an aromatic ring. Therefore, when the positive A plate is formed using only the first photopolymerizable liquid crystal (A) having an aliphatic ring and not having an aromatic ring, it has good heat resistance against the manufacturing process of the liquid crystal display device. May not be able to express sex. For example, there is a possibility that optical characteristics may change in the manufacturing process of the liquid crystal display device.
Therefore, by using the first photopolymerizable liquid crystal (A) and the second photopolymerizable liquid crystal (B) in combination, the wavelength dispersion characteristics of birefringence are improved and the manufacturing process of the liquid crystal display device is improved. A positive A plate having good heat resistance can be formed.

In the composition (Y), the amount of the first photopolymerizable liquid crystal (A) is 50% by mass or more and less than 100% by mass with respect to the total amount of the photopolymerizable liquid crystal, and the second photopolymerizable liquid crystal (B ) Is more than 0% by mass and 50% by mass or less.
If the first photopolymerizable liquid crystal (A) is contained in an amount of 50% by mass or more and the second photopolymerizable liquid crystal (B) is contained in an amount of 50% by mass or less, a positive A plate exhibiting suitable wavelength dispersion can be formed. Further, if the first photopolymerizable liquid crystal (A) is contained in an amount of less than 100% by mass and the second photopolymerizable liquid crystal (B) is contained in an amount of more than 0% by mass, a positive A plate having good heat resistance can be formed. .
Preferably, in the composition (Y), the amount of the first photopolymerizable liquid crystal (A) is 50 to 90% by mass with respect to the total amount of the photopolymerizable liquid crystal, and the second photopolymerizable liquid crystal (B ) Is 50 to 10% by mass. More preferably, in the composition (Y), the amount of the first photopolymerizable liquid crystal (A) is 70 to 90% by mass with respect to the total amount of the photopolymerizable liquid crystal, and the second photopolymerizable liquid crystal ( The amount of B) is 30 to 10% by mass.

The Re (450) / Re (590) of the positive A plate obtained using the composition (Y) is preferably 1.07 or less, and more preferably 1.05 or less.
When the positive A plate obtained using the composition (Y) is baked at 230 ° C. for 30 minutes, the change rate of Re (590) before and after baking is preferably 5% or less.

Since the first photopolymerizable liquid crystal (A) can form a positive A plate exhibiting wavelength dispersion, it can contain one or more monofunctional photopolymerizable liquid crystals and / or bifunctional photopolymerizable liquid crystals.
The first photopolymerizable liquid crystal (A) is preferably composed of one or two types of monofunctional photopolymerizable liquid crystal and / or bifunctional photopolymerizable liquid crystal, and monofunctional photopolymerizable liquid crystal or bifunctional photopolymerization. More preferably, it is made of one kind of conductive liquid crystal.

Examples of the monofunctional photopolymerizable liquid crystal suitable for use in the first photopolymerizable liquid crystal (A) include compounds represented by the following formula (11).
_{^{CH 2 = CR 11 -COO- (L}} 1) a1 -E 11 - (S 1) b1 -E 12 - (T 1) c1 - (E 13) d1 -R 12 ··· (11)

In the photopolymerizable liquid crystal (11), R ¹¹ is a hydrogen atom or a methyl group, and preferably a hydrogen atom. When R ¹¹ is a hydrogen atom, the polymerization can proceed rapidly when the composition (Y) containing the photopolymerizable liquid crystal (11) is photopolymerized. In addition, the optical characteristics of the obtained optical compensation film are hardly affected by the external environment such as temperature, and there is an advantage that variation in retardation Re of the optical compensation film can be reduced.

In the photopolymerizable liquid crystal (11), R ¹² is an alkyl group having 1 to 8 carbon atoms or a fluorine atom. In the case of an alkyl group, R ¹² may have an etheric oxygen atom between carbon-carbon bonds or at the terminal bonded to the ring group, and a part or all of the hydrogen atoms are substituted with fluorine atoms. May be.
By using R ¹² as the above group, the melting point (T _m : crystalline phase-nematic phase transition point) of the composition (Y) containing the photopolymerizable liquid crystal (11) can be lowered. R ¹² is preferably an alkyl group having 2 to 6 carbon atoms or a fluorine atom. Furthermore, since the temperature range in which the photopolymerizable liquid crystal (11) exhibits liquid crystallinity can be widened, when R ¹² is an alkyl group, a linear structure is preferable.

In the photopolymerizable liquid crystal (11), L ¹ may have an etheric oxygen atom between carbon-carbon bonds, and part or all of the hydrogen atoms may be substituted with fluorine atoms. , E ¹¹ is an alkyl group having 1 to 8 carbon atoms, which may have COO, OCO or O at the bonding position. L ¹ is preferably — (CH ₂ ) _p1 COO—, — (CH ₂ ) _p1 OCO—, — (CH ₂ ) _p1 O— or — (CH ₂ ) _p1 —, and p1 is preferably an integer of 1 to 8. . L ¹ is more preferably — (CH ₂ ) _p1 COO—, and p1 is more preferably an integer of 1 to 8.
In general, when a photopolymerizable liquid crystal is polymerized, the value of refractive index anisotropy Δn tends to decrease before and after polymerization. However, when L ¹ is a group having the above polymethylene group, a decrease in Δn value before and after polymerization can be suppressed. Furthermore, from the viewpoint of securing liquid crystallinity before polymerization, p1 is preferably an integer of 2 to 4.

In the photopolymerizable liquid crystal (11), E ¹¹ , E ¹² and E ¹³ are each independently a trans-1,4-cyclohexylene group or a trans-2,6-decahydronaphthalene group. In E ¹¹ , E ¹² and E ¹³ , a hydrogen atom bonded to a carbon atom in the group may be substituted with a fluorine atom or a methyl group. However, in the present invention, in the trans-1,4-cyclohexylene group and trans-2,6-decahydronaphthalene group, the hydrogen atom bonded to the carbon atom in these groups is not substituted with another group. Unsubstituted groups are preferred.

In the photopolymerizable liquid crystal (11), S ¹ and T ¹ are each independently —OCO—, —COO—, — (CH ₂ ) ₂ —, —CH ₂ O—, —OCH ₂ — or a single bond. . From the viewpoint of liquid crystal expression of the compound, a single bond is preferable.

  In the photopolymerizable liquid crystal (11), a1, b1, c1 and d1 are each independently 0 or 1.

The photopolymerizable liquid crystal (11) preferably has the following group (I) or group (II) in the molecule.

  Specific examples of the photopolymerizable liquid crystal (11) having the group (I) include the following compound (11A). The symbols in the compound (11A) are as described above. In addition, when the group of structural isomerism exists in the alkyl group in a formula, all the groups are included and a linear alkyl group is preferable.

In the compound (11A), R ¹¹ is preferably a hydrogen atom, a1 is preferably 0 or 1, and R ¹² is preferably a linear alkyl group having 2 to 6 carbon atoms or a fluorine atom. L ¹ is preferably-(CH ₂ ) _p1 COO- or-(CH ₂ ) _p1 OCO- because a wider liquid crystallinity can be secured. Further, L ¹ is particularly preferably — (CH ₂ ) _p1 COO— because the number of synthesis steps is reduced. P1 is particularly preferably an integer of 2 to 4.

As the compound (11A), the following compounds may be mentioned. The symbols in these compounds are as described above. p1 is preferably an integer of 2 to 4. The trans-2,6-decahydronaphthalene group is preferably a trans-2,6-transdecahydronaphthalene group from the viewpoint of developing liquid crystallinity. R ¹² is preferably a linear alkyl group having 2 to 6 carbon atoms.

  See paragraphs 0050-0056 of Patent Document 3 for the synthesis methods of the compounds (11A-1) and (11A-2).

  Specific examples of the photopolymerizable liquid crystal (11) having the group (II) include the following compounds (11B) to (11D). The symbols in the compound are as described above. In addition, when the group of structural isomerism exists in the alkyl group in a formula, all the groups are included and a linear alkyl group is preferable.

In the compounds (11B) to (11D), R ¹¹ is a hydrogen atom, a1 is 0 or 1, and R ¹² is preferably a linear alkyl group having 2 to 6 carbon atoms or a fluorine atom. L ¹ is preferably-(CH ₂ ) _p1 COO- or-(CH ₂ ) _p1 OCO- because a wider liquid crystallinity can be secured. Here, p1 is particularly preferably an integer of 2 to 4.

Examples of the compounds (11B) to (11D) include the compounds shown below. The symbols in these compounds are as described above. p1 is preferably an integer of 2 to 4. R ¹² is preferably a linear alkyl group having 2 to 6 carbon atoms. In addition, when the group of structural isomerism exists in the alkyl group in a formula, all the groups are included and a linear alkyl group is preferable.

  The compounds (11B) to (11D) can also be produced by applying a known synthesis method as in the case of the compound (11A).

Examples of the bifunctional photopolymerizable liquid crystal suitable for use in the first photopolymerizable liquid crystal (A) include compounds represented by the following formula (12).
_{^{CH 2 = CR 21 -COO- (L}} 2) a2 -E 21 - (S 2) b2 -E 22 - (T 2) c2 - (E 23) d2 - (M 2) e2 -OCO-CR 22 = CH ₂ ... (12)

In the photopolymerizable liquid crystal (12), R ²¹ and R ²² are each independently a hydrogen atom or a methyl group, preferably a hydrogen atom. When R ²¹ and R ²² are hydrogen atoms, the polymerization can proceed rapidly when the composition (Y) containing the photopolymerizable liquid crystal (12) is photopolymerized. Further, there is an advantage that the optical characteristics of the obtained optical compensation film are not easily affected by the external environment such as temperature, and variations in retardation Re of the optical compensation film are reduced.

In the photopolymerizable liquid crystal (12), L ² may have an etheric oxygen atom between carbon-carbon bonds, and part or all of the hydrogen atoms may be substituted with fluorine atoms. , E ²¹ is an alkyl group having 1 to 8 carbon atoms that may have COO, OCO, or O at the bonding position. L ² is preferably — (CH ₂ ) _{p 2} COO—, — (CH ₂ ) _{p 2} OCO—, — (CH ₂ ) _{p 2} O— or — (CH ₂ ) _{p 2} —, and p 2 is preferably an integer of 1 to 8. . L ² is more preferably — (CH ₂ ) _p2 COO— from the viewpoint of liquid crystal expression of the compound, and p2 is more preferably an integer of 1 to 8.

In the photopolymerizable liquid crystal (12), M ² may have an etheric oxygen atom between carbon-carbon bonds, and part or all of the hydrogen atoms may be substituted with fluorine atoms. , E ²³ is an alkyl group having 1 to 8 carbon atoms which may have COO, OCO, or O at the bonding position. M ² is preferably —OCO (CH ₂ ) _{q 2} —, —COO (CH ₂ ) _{q 2} —, —O (CH ₂ ) _{q 2} — or — (CH ₂ ) _{q 2} —, and q ₂ is preferably an integer of 1 to 8. . M ^2, from the viewpoint of the liquid crystal expression of compounds, -OCO _{(CH 2) q2} - or - _{(CH 2) q2} - are more preferable, q2 is more preferably an integer of 1 to 8, -OCO _(CH 2) _q2- is particularly preferred, and q2 is particularly preferably an integer of 1-8.

In general, when a photopolymerizable liquid crystal is polymerized, the value of refractive index anisotropy Δn tends to decrease before and after polymerization. However, when L ² and M ² are groups having the above polymethylene group, a decrease in Δn value before and after the polymerization can be suppressed. Furthermore, from the viewpoint of securing liquid crystallinity before polymerization, p2 and q2 are each preferably preferably an integer of 2 to 4.

In the photopolymerizable liquid crystal (12), E ²¹ , E ²² and E ²³ are each independently a trans-1,4-cyclohexylene group or a trans-2,6-decahydronaphthalene group. In E ²¹ , E ²² and E ²³ , a hydrogen atom bonded to a carbon atom in the group may be substituted with a fluorine atom or a methyl group. However, in the present invention, in the trans-1,4-cyclohexylene group and trans-2,6-decahydronaphthalene group, the hydrogen atom bonded to the carbon atom in these groups is not substituted with another group. Unsubstituted groups are preferred.

In the photopolymerizable liquid crystal (12), S ² and T ² are each independently —OCO—, —COO—, — (CH ₂ ) ₂ —, —CH ₂ O—, —OCH ₂ — or a single bond. is there. From the viewpoint of liquid crystal expression of the compound, a single bond is preferable.

  In the photopolymerizable liquid crystal (12), a2, b2, c2, d2 and e2 are each independently 0 or 1.

The photopolymerizable liquid crystal (12) preferably has the following group (I) or group (II) in the molecule.

  Specific examples of the photopolymerizable liquid crystal (12) having the group (I) include the following compound (12A). The symbols in the compound (12A) are as described above. In addition, when the group of structural isomerism exists in the alkyl group in a formula, all the groups are included and a linear alkyl group is preferable.

In the compound (12A), R ²¹ and R ²² are preferably hydrogen atoms, and a2 and e2 are each independently preferably 0 or 1. From the viewpoint of ensuring liquid crystallinity, p2 and q2 are each particularly preferably an integer of 2 to 4 independently.

  Examples of the compound (12A) include the following compounds. The symbols in these compounds are as described above. p2 and q2 are preferably each independently an integer of 2 to 4. The trans-2,6-decahydronaphthalene group is preferably a trans-2,6-transdecahydronaphthalene group from the viewpoint of developing liquid crystallinity.

  See paragraphs 0055-0057 of Patent Document 4 for the synthesis methods of the compounds (12A-1) and (12A-2).

  Specific examples of the photopolymerizable liquid crystal (12) having the group (II) include the following compound (12B). The symbols in the compound (12B) are as described above. In addition, when the group of structural isomerism exists in the alkyl group in a formula, all the groups are included and a linear alkyl group is preferable.

In the compound (12B), R ²¹ and R ²² are each a hydrogen atom, and a2 and e2 are preferably each independently 0 or 1. From the viewpoint of ensuring liquid crystallinity, p2 and q2 are each particularly preferably an integer of 2 to 4 independently.

  Examples of the compound (12B) include the following compounds. The symbols in these compounds are as described above. It is preferable that p2 and q2 are each independently an integer of 2 to 4.

  Similarly to the compound (12A), the compound (12B) can also be produced by applying a known synthesis method.

  The second photopolymerizable liquid crystal (B) can contain one or more monofunctional photopolymerizable liquid crystals and / or bifunctional photopolymerizable liquid crystals. The second photopolymerizable liquid crystal (B) preferably contains one or more bifunctional photopolymerizable liquid crystals from the viewpoint of improving heat resistance.

As the second photopolymerizable liquid crystal (B), a compound represented by the following formula (20) is preferable.
^{Q 1 -Z 1 -A 1 -Z 3} -M-Z 4 -A 2 -Z 2 -Q 2 ··· (20)
The symbols in the formula have the following meanings.
Q ¹ and Q ² are each independently a photopolymerization reactive group.
Z ¹ , Z ² , Z ³ and Z ⁴ are each independently a single bond or a divalent linking group.
A ¹ and A ² are each independently a spacer group having 2 to 20 carbon atoms.
M is a mesogenic group containing an aromatic ring.

  As the second photopolymerizable liquid crystal (B), a compound represented by the following formula (21), (22), (23) or (24) is preferable.

^{_{CH 2 = CR 41 -COO- (E}} 41) m4 -Cy-Y 4 -Cy- (E 42) n4 -OCO-CR 42 = CH 2 ··· (21)

In the photopolymerizable liquid crystal (21), R ⁴¹ and R ⁴² are each independently a hydrogen atom or a methyl group, preferably a hydrogen atom. When R ⁴¹ and R ⁴² are hydrogen atoms, the polymerization can proceed rapidly when the composition (Y) containing the photopolymerizable liquid crystal (21) is photopolymerized. In addition, there is an advantage that the optical characteristics of the obtained optical compensation film are hardly affected by the external environment such as temperature, and variations in retardation Re are reduced in the plane of the optical compensation film.

Y ⁴ is —OCO— or —COO—. -OCO- is preferable in that the melting point ( _Tm ) can be lowered, and -COO- is preferable in that a large Δn can be expressed when an optical compensation film is formed.

m4 and n4 are each independently 0 or 1, and at least one is 1.
E ⁴¹ and E ⁴² are each independently a 1,4-phenylene group (Ph) or a trans-1,4-cyclohexylene group (Cy). However, at least one of E ⁴¹ and E ⁴² is a 1,4-phenylene group.
In the 1,4-phenylene group (Ph) and trans-1,4-cyclohexylene group (Cy), a hydrogen atom in the group may be substituted with a fluorine atom, a chlorine atom, or a methyl group.

_{^{CH 2 = CR 51 -COO- (L}} 5) k5 -E 51 -E 52 -E 53 -E 54 - (M 5) n5 -OCO-CR 52 = CH 2 ··· (22)

In the photopolymerizable liquid crystal (22), R ⁵¹ and R ⁵² are each independently a hydrogen atom or a methyl group, preferably a hydrogen atom.
k5 and n5 are each independently 0 or 1, and 1 is preferable.
L ⁵ :-( CH _{2) p5} O- or - (CH _{2) p5} - (wherein, p5 2-8 integer)..
M ⁵ : —O (CH ₂ ) _p5 — or — (CH ₂ ) _p5 — (wherein p5 is an integer of 2 to 8).
In general, when a photopolymerizable liquid crystal is polymerized, the value of Δn tends to decrease before and after the polymerization, but when L ⁵ and M ⁵ are groups having the above polymethylene group, the Δn value before and after the polymerization Can be suppressed.
E ⁵¹ is preferably a 1,4-phenylene group (Ph).
E ⁵² , E ⁵³ and E ⁵⁴ are each independently 1,4-phenylene group (Ph) or trans-1,4-cyclohexylene group (Cy), and at least one of E ⁵² and E ⁵³ is trans-1 , 4-cyclohexylene group (Cy).
In the 1,4-phenylene group (Ph) and trans-1,4-cyclohexylene group (Cy), a hydrogen atom bonded to a carbon atom in the group is substituted with a fluorine atom, a chlorine atom or a methyl group. May be.

_{^{CH 2 = CR 61 -COO- (L}} 6) k6 -E 61 -E 62 -E 63 - (M 6) n6 -OCO-CR 62 = CH 2 ··· (23)

In the photopolymerizable liquid crystal (23), R ⁶¹ and R ⁶² are each independently a hydrogen atom or a methyl group, preferably a hydrogen atom.
k6 and n6 are each independently 0 or 1, and 1 is preferable.
L ⁶ : — (CH ₂ ) _{p 6} O—, —Cy—COO— (Cy is a trans-1,4-cyclohexylene group), or —Cy—OCO— (where p6 is an integer of 2 to 8). ).
M ⁶ : —O (CH ₂ ) _p6 —, —OCO—Cy— (Cy is a trans-1,4-cyclohexylene group), or —COO—Cy— (where p6 is an integer of 2 to 8). ).
E ⁶¹ , E ⁶² and E ⁶³ are each independently a 1,4-phenylene group or a trans-1,4-cyclohexylene group. However, at least one of E ⁶¹ , E ⁶² and E ⁶³ is a 1,4-phenylene group, and at least one is a trans-1,4-cyclohexylene group. In the case where L ⁶ is —Cy—OCO—, E ⁶¹ is a trans-1,4-cyclohexylene group, and L ⁶ is — (CH ₂ ) _p6 O— or k6 is 0. Each of E ⁶¹ and E ^{63 in} the formula is a 1,4-phenylene group, and E ⁶² is a trans-1,4-cyclohexylene group.
In the 1,4-phenylene group (Ph) and trans-1,4-cyclohexylene group (Cy), a hydrogen atom bonded to a carbon atom in the group is substituted with a fluorine atom, a chlorine atom, or a methyl group. May be.

_{^{CH 2 = CR 71 -COO- (L}} 7) k7 -Ph- (X 7) -Ph- (Y 7) -Ph- (M 7) n7 -OCO-CR 72 = CH 2 ··· (24)

In the photopolymerizable liquid crystal (24), R ⁷¹ and R ⁷² are each independently a hydrogen atom or a methyl group, preferably a hydrogen atom.
X ⁷ and Y ⁷ are each independently —OCO— or —COO—.
_{^{L 7 :-( CH 2) p7 O}} -, - (CH 2) p7 O-COO -, - (CH 2) p7 OCO- or _{- (CH} 2) p7 COO- (wherein, p7 is of 2-8 integer.).
M ⁷ : —O (CH ₂ ) _{p 7} —, OCO—O (CH ₂ ) _{p 7} —, —OCO— (CH ₂ ) _{p 7} or —COO (CH ₂ ) _{p 7} — (where p 7 is an integer of 2 to 8) .)
k7 and n7 are each independently 0 or 1.
Ph is a 1,4-phenylene group.
In the 1,4-phenylene group, a hydrogen atom bonded to a carbon atom in the group may be substituted with a fluorine atom, a chlorine atom or a methyl group.

  In addition to the first photopolymerizable liquid crystal (A) and the second photopolymerizable liquid crystal (B), the composition (Y) includes a known photopolymerization initiator (C), a known surfactant (D), A known solvent (E) or other optional components can be contained.

  Examples of the photopolymerization initiator (C) include oxime esters, acetophenones, benzophenones, acylphosphine oxides, benzoins, benzyls, Michler ketones, benzoin alkyl ethers, and benzyl dimethyl ketals. These can be used by appropriately selecting one kind or two or more kinds.

  Oxime esters include 1,2-octanedione, 1- [4- (phenylthio)-, 2- (ortho-benzoyloxime)], and ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) ) -9H-carbazol-3-yl]-, 1- (ortho-acetyloxime).

  As acetophenones, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl)- Butanone-12- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2-hydroxy-1- {4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 2-methyl-1- (4-methylthiophenyl) -2 And morpholinopropan-1-one and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one. It is done.

  Acylphosphine oxides include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -diphenyl-phosphine oxide.

Examples of the surfactant (D) include surfactants such as the following anionic surfactants, nonionic surfactants, chaotic surfactants, and amphoteric surfactants.
Anionic surfactants; sodium lauryl sulfate, ammonium lauryl sulfate, triethanolamine lauryl sulfate, polyoxyethylene alkyl ether sulfate, alkyl ether phosphate, sodium oleyl succinate, potassium myristic acid, potassium coconut oil fatty acid and sodium lauroyl sarcosine Nate etc.
Nonionic surfactants such as polyethylene glycol monolaurate, sorbitan stearate, glyceryl myristate, glyceryl dioleate, sorbitan stearate and sorbitan oleate.
Chaotic surfactants: stearyl trimethyl ammonium chloride, behenyl trimethyl ammonium chloride, stearyl dimethyl benzyl ammonium chloride, cetyl trimethyl ammonium chloride and the like.
Amphoteric surfactants; alkylbetaines such as laurylbetaine, alkylsulfobetaine, cocamidopropylbetaine and alkyldimethylaminoacetic acid betaine, alkylimidazolines, sodium lauroyl sarcosine and sodium cocoamphoacetate.
Any of these surfactants may be used alone, or two or more thereof may be used in combination.

As the solvent (E), cyclohexanone, ethyl cellosolve acetate, butyl cellosolve acetate, 1-methoxy-2-propyl acetate, diethylene glycol dimethyl ether, ethylbenzene, ethylene glycol diethyl ether, xylene, ethyl cellosolve, methyl-n amyl ketone, propylene glycol monomethyl ether, Examples include toluene, methyl ethyl ketone, ethyl acetate, methanol, ethanol, isopropyl alcohol, butanol and isobutyl ketone.
Any of these solvents may be used alone or in combination of two or more.

  Other optional components include antioxidants, ultraviolet absorbers, silane coupling agents, light stabilizers, and the like.

  When the total amount other than the solvent (E) in the composition (Y) is 100% by mass, the first photopolymerizable liquid crystal (A) and the second photopolymerizable liquid crystal (B) in the composition (Y) 80 mass% or more and less than 100 mass% is preferable, and 90 mass% or more and less than 100 mass% is especially preferable.

[Optical compensation film]
The optical compensation film of the present invention is an optical compensation film (positive A plate) having positive uniaxial anisotropy formed by photocuring the coating film of the above-described photopolymerizable liquid crystal composition of the present invention.
Re (450) / Re (590) of the positive A plate of the present invention is preferably 1.07 or less, and more preferably 1.05 or less.
When the positive A plate of the present invention is baked at 230 ° C. for 30 minutes, the Re (590) change rate before and after baking is preferably 5% or less.

[Optical compensation laminated film]
The optical compensation laminated film of the present invention comprises an optical compensation film exhibiting negative uniaxial anisotropy (negative C plate) and an optical compensation film exhibiting positive uniaxial anisotropy of the present invention described above (positive A plate). Obtained by lamination.

  In the optical compensation laminated film of the present invention, the order in which the optical compensation films are laminated is not limited. An alignment film may be provided between the negative C plate and the positive A plate. That is, the optical compensation film of the present invention can form an optical compensation laminated film in any of the forms (i) to (iv) described above. Among these, from the viewpoint of thinning the optical compensation laminated film, the form (iv), that is, the form in which the positive A plate is laminated directly on the negative C plate having orientation is preferable.

The composition of the negative C plate forming material having orientation (hereinafter sometimes referred to as composition (X)) preferably includes polyimide (PI) or a precursor thereof, polyamic acid (PAA). . It is preferable that the composition (X) contains polyamic acid (PAA) because birefringence in the thickness direction is exhibited during thermal imidization.
Here, the polyimide film basically has orientation. For this reason, it is preferable to select a material that forms a negative C plate, that is, exhibits birefringence in the thickness direction, among polyimide (PI) or polyamic acid (PAA) for forming an alignment film of a liquid crystal display device.
All polyimides have good heat resistance. Therefore, it is preferable to use polyimide as the negative C plate because the heat resistance is good as the optical compensation film.

Polyimide is obtained by a polymerization reaction between an acid anhydride and a diamine. From the viewpoint of improving the translucency of polyimide, it is preferable to have an aliphatic ring in the skeleton. In this case, what has an aliphatic ring in the skeleton may be selected as the acid anhydride or diamine.
When the acid anhydride has an aliphatic ring, examples of the acid anhydride include 1,2,3,4-butanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic Acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride And 3,3 ′, 4,4′-dicyclohexanetetracarboxylic dianhydride and the like, and examples of the diamine include 2,2′-bis (trifluoromethyl) benzidine and p-phenylenediamine.
When the diamine has an aliphatic ring, as the acid anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride And 1,2,5,6-naphthalenetetracarboxylic dianhydride and the like, and examples of the diamine include trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane and 4,4′-diamino-1 1'-bicyclohexanoxane and the like can be mentioned.

The composition (X) can contain one or more known solvents or one or more other optional components.
As for content of a polyimide (PI) or polyamic acid (PAA) with respect to the whole composition (X), 10-30 mass% is preferable.

The process of forming a negative C plate having orientation is, for example,
A step (S1) of forming a first coating film by applying a composition (X) preferably containing polyamic acid (PAA) and a solvent on a substrate by a spin coating method or the like;
A step of removing the solvent in the first coating film by heating drying (pre-baking) at about 150 ° C., drying under reduced pressure, or drying under reduced pressure (S2);
Baking (post-baking) the polyamic acid in the coating film at about 230 ° C. to generate a polyimide film (S3);
And a step (S4) of performing a rubbing process on the polyimide film.

The process for forming the positive A plate is, for example,
On the negative C plate, the photopolymerizable liquid crystal composition (Y) of the present invention containing the first photopolymerizable liquid crystal (A) and the second photopolymerizable liquid crystal (B) is applied, Forming a second coating film (S5);
Removing the solvent in the second coating film by heating drying (pre-baking) at about 80 ° C., drying under reduced pressure, or drying under reduced pressure (S6);
Irradiating the second coating film with light such as ultraviolet light (UV) to photopolymerize the photopolymerizable liquid crystals (A) and (B) (S7).
Only by light irradiation, unreacted photopolymerizable liquid crystals (A) and (B) may remain. In this case, you may implement the process (S8) baked at about 230 degreeC after a process (S7).

The optical compensation laminated film of the present invention is suitable for a vertical alignment (VA) mode liquid crystal display device.
In the optical compensation laminated film, the retardation Rth, which is an index of birefringence in the z direction, is preferably from 100 to 500 nm, particularly preferably from 200 to 300 nm.
In the optical compensation laminated film, the retardation Re, which is an index of birefringence in the xy plane, is preferably more than 0 nm and not more than 100 nm, and particularly preferably 40 to 60 nm.

Since the optical compensation laminated film of the present invention does not require a base film, the liquid crystal display device can be thinned.
In particular, in an optical compensation laminated film composed of a negative C plate having orientation and a positive A plate directly laminated thereon, an alignment film is not required in the optical compensation laminated film, and the thickness can be further reduced. It is done. Further, if the number of films is small, the number of manufacturing steps is reduced, and the manufacturing cost can be reduced.

  In the present invention, the thicknesses da and db of the negative C plate and the positive A plate are both preferably 10 μm or less, and more preferably 5 μm or less. Therefore, the thickness d of the optical compensation laminated film can be 20 μm or less, and further can be 10 μm or less.

  In the optical compensation laminated film of the present invention, the average transmittance at a wavelength of 400 nm to 800 nm is preferably 80% or more, more preferably 85% or more. In this specification, “average transmittance” is a value measured according to JISK 7361-1.

  The optical compensation laminated film of the present invention has improved Re wavelength dispersion characteristics and good optical characteristics. In addition, its optical characteristics have good heat resistance for the manufacturing process of the liquid crystal display device.

[Liquid Crystal Display]
The liquid crystal display device according to one embodiment of the present invention is a VA mode color transmission type TFT liquid crystal display device.
This embodiment can also be applied to other active matrix types such as monochrome liquid crystal display devices, reflective or transflective liquid crystal display devices, and TFD liquid crystal display devices, or passive matrix types.

As shown in FIG. 1, the liquid crystal display device 1 of the present embodiment includes a liquid crystal cell 1A, polarizers 51 and 52 attached to the outside thereof, and a backlight BL.
The liquid crystal cell 1 includes a color filter substrate 10, a TFT substrate 20 that is a counter substrate, and a liquid crystal layer 30 that is sandwiched between the pair of substrates.

The color filter substrate (electrode substrate, liquid crystal display substrate) 10 includes a translucent substrate 11, a black matrix layer BM, a color filter layer CF, and an optical compensation laminated film 12 that are sequentially laminated on the liquid crystal layer 30 side. An electrode 13 and an alignment film 14 are provided.
The TFT substrate 20 includes a pixel electrode substrate 21 in which a plurality of pixel electrodes and a plurality of TFTs (thin film transistors) which are switching elements of the pixel electrodes are formed in a matrix on the liquid crystal layer 30 side of the translucent substrate, And an alignment film 22 formed on the liquid crystal layer 30 side.

As a translucent substrate used for the color filter substrate 10 and the TFT substrate 20, a glass substrate is preferable.
In the transmissive liquid crystal display device 1, a light-transmitting conductive material such as ITO (indium tin oxide) is used as a material for the common electrode 13 and the pixel electrode.
The black matrix layer BM is a light shielding layer that shields light between adjacent dots.
The color filter layer CF includes, for example, red (R), green (G), and blue (B) colored layers. In this case, three pixel electrodes and three colored layers are formed in one pixel (1 pixel = 3 dots).
The optical compensation laminated film 12 is the optical compensation laminated film of the present invention described above, and is preferably a laminated film of a negative C plate 12A and a positive A plate 12B as shown in FIG.
In the present embodiment, the common electrode 13 is formed immediately above the optical compensation laminated film 12, and the alignment film 14 is formed thereon.

The design of the laminated structure of the color filter substrate 10 can be changed as appropriate.
For example, as shown in the color filter substrate 40, the liquid crystal cell 2A, and the liquid crystal display device 2 of the design change shown in FIG. The common electrode 13 and the alignment film 14 may be sequentially provided.

  The color filter substrate (electrode substrate, liquid crystal display substrate) 10 and the liquid crystal display device 1 of the present embodiment have good optical characteristics and heat resistance. Since the color filter substrate 10 and the liquid crystal display device 1 of the present embodiment include the optical compensation laminated film 12 in the liquid crystal cell 1A, the thickness and cost can be reduced.

  Hereinafter, the present invention will be described based on examples, but the present invention is not limited thereto. Examples 11 and 12 and Examples 21 and 22 are Examples, and Examples 13 and 14 and Examples 23 and 24 are Comparative Examples.

  The following compounds (A1), (A2), and (B1) were prepared as photopolymerizable liquid crystals for the positive A plate.

The other materials of the positive A plate are as follows.
Photopolymerization initiator (C1): “Irgacure 907” manufactured by BASF.
Surfactant (D1): A fluorine-based nonionic surfactant “Surflon S420” manufactured by AGC Seimi Chemical Co., Ltd.
Solvent (E1): cyclopentanone.

[Example 11: Preparation of coating liquid (Y1) for positive A plate]
0.75 g of photopolymerizable liquid crystal (A1) and 0.25 g of photopolymerizable liquid crystal (B1) were mixed to obtain a liquid crystal composition. To the composition, 5% by mass of the photopolymerization initiator (C1) and 1% by mass of the surfactant (D1) were weighed and mixed. Thereafter, the solvent (E1) was added and mixed to obtain a 15% by mass solution. This was filtered with a filter having an opening diameter of 0.5 μm to obtain a coating solution (Y1).
The composition is shown in Table 1.

[Example 12: Preparation of coating solution for positive A plate (Y2)]
A coating solution (Y2) was obtained in the same manner as in Example 11 except that the composition was as shown in Table 1.

[Examples 13 and 14: Preparation of coating solutions (Z1) and (Z2) for positive A plate]
Coating solutions (Z1) and (Z2) were obtained in the same manner as in Example 11 except that the composition was as shown in Table 1.

[Example 21: Production of optical compensation laminated film]
<Deposition of negative C plate (NC1)>
1.14 g of trans-1,4-diaminocyclohexane is dissolved in 17.44 g of N-methyl-2-pyrrolidone, and 2.83 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and N-methyl are dissolved. -2-pyrrolidone (4.00 g) was added, and the mixture was stirred at 60 ° C. for 3 hours. Further, 0.12 g of phthalic anhydride was added, and the mixture was stirred at 60 ° C. for 3 hours to obtain a polyamic acid (PAA1) solution. This was filtered with a filter having an opening diameter of 0.5 μm to obtain a coating solution (X1). This coating solution was applied onto a glass substrate with a spin coater (3000 rpm, 30 sec), and dried on a hot plate at 90 ° C. for 2 minutes. Further, after heating at 230 ° C. for 30 minutes, a rubbing treatment was performed to form a negative C plate (NC1) having an alignment film function. The film thickness was 3.1 μm, the birefringence index P at 590 nm in the thickness direction was 0.090, and Rth = 279 nm.
<Deposition of positive A plate (PA1)>
The coating solution (Y1) was coated on the negative C plate (NC1) with a spin coater and dried at 80 ° C. for 2 minutes to adjust the orientation. Thereafter, ultraviolet rays were irradiated for 60 seconds from the direction perpendicular to the substrate surface, the coating film was cured, and a positive A plate (PA1) was formed. The illuminance of the high-pressure mercury lamp used for photocuring was 190 mW / cm ² at a wavelength of 365 nm.
An optical compensation laminated film was obtained as described above.
Table 1 shows the main manufacturing conditions.

[Example 22: Production of optical compensation laminated film]
In the same manner as in Example 21, a negative C plate (NC1) was formed.
A positive A plate (PA2) was formed on the negative C plate (NC1) in the same manner as in Example 21 except that the coating liquid (Y2) was used instead of the coating liquid (Y1). A compensation laminated film was obtained.
Table 1 shows the main production conditions for each example.

[Examples 23 and 24: Production of optical compensation laminated film]
In the same manner as in Example 21, a negative C plate (NC1) was formed.
On the negative C plate (NC1), positive A plates (PA3) and (PA4) were prepared in the same manner as in Example 21 except that the coating liquids (Z1) and (Z2) were used instead of the coating liquid (Y1). ) To obtain an optical compensation laminated film.
Table 1 shows the main production conditions for each example.

[Evaluation]
(Re measurement)
About the obtained optical compensation laminated film, Re when the wavelength was changed in the visible light region (400 to 800 nm) was measured. From the obtained data, the value of Re (450) / Re (590) was determined.
(Heat-resistant)
The obtained optical compensation laminated film was baked at 230 ° C. for 30 minutes, and the change rate of Re (590) before and after baking was determined. Evaluation was made based on the following criteria. Good (◯): 0 to 5%, acceptable (Δ): 5 to 10%, impossible (×): 10% or more.

[result]
4A to 4D show Re measurement graphs with respect to wavelength in the optical compensation laminated films of Examples 21 to 24. FIG.
Table 1 shows the evaluation results of Re (450) / Re (590) and heat resistance.
In the optical compensation laminated film of Example 23 using only the second photopolymerizable liquid crystal (B) having an aromatic ring as the photopolymerizable liquid crystal of the positive A plate material, the decrease level of Re with respect to the increase in wavelength is large. (450) / Re (590) was 1.10.
In the optical compensation laminated film of Example 24 using only the first photopolymerizable liquid crystal (A) having no aromatic ring as the photopolymerizable liquid crystal of the positive A plate material, the decrease in Re with respect to the increase in wavelength is suppressed, Re (450) / Re (590) was 1.02. However, the change rate of Re (590) before and after baking at 230 ° C. was 5 to 10%, and the heat resistance was insufficient.
Examples 21 and 22 in which the first photopolymerizable liquid crystal (A) having no aromatic ring and the second photopolymerizable liquid crystal (B) having an aromatic ring are used in combination as the photopolymerizable liquid crystal of the positive A plate material. In the optical compensation laminated film, the decrease in Re with respect to the increase in wavelength was suppressed, and Re (450) / Re (590) was 1.04. Moreover, the change rate of Re (590) before and after baking at 230 ° C. was within 5%, and the heat resistance was also good.

  It should be noted that the entire content of the specification, claims, drawings and abstract of Japanese Patent Application No. 2013-002538 filed on January 10, 2013 is cited here as the disclosure of the specification of the present invention. Incorporated.

1, 2: Liquid crystal display device, 1A, 2A: Liquid crystal cell, 10, 40: Color filter substrate (electrode substrate, substrate for liquid crystal display device), 11: Translucent substrate, 12: Optical compensation laminated film, 12A: Negative C plate (optical compensation film exhibiting negative uniaxial anisotropy), 12B: positive A plate (optical compensation film exhibiting positive uniaxial anisotropy), 13: common electrode, 14: alignment film, 20: TFT substrate, 21: Pixel electrode substrate, 22: Alignment film, 30: Liquid crystal layer, 51, 52: Polarizer, BM: Black matrix, CF: Color filter, BL: Backlight.

Claims (15)

A photopolymerizable liquid crystal composition for forming an optical compensation film exhibiting positive uniaxial anisotropy,
A first photopolymerizable liquid crystal (A) having an aliphatic ring and no aromatic ring;
A second photopolymerizable liquid crystal (B) having an aromatic ring,
The amount of the first photopolymerizable liquid crystal (A) is 50% by mass or more and less than 100% by mass, and the amount of the second photopolymerizable liquid crystal (B) is 0% by mass with respect to the total amount of the photopolymerizable liquid crystal. A photopolymerizable liquid crystal composition having an ultra-50% by mass or less.   The first photopolymerizable liquid crystal (A) is a monofunctional photopolymerizable liquid crystal containing one photopolymerizable reactive group in one molecule and / or a bimonofunctional containing two photopolymerizable reactive groups in one molecule. The photopolymerizable liquid crystal composition according to claim 1, comprising a photopolymerizable liquid crystal. The photopolymerizable liquid crystal composition according to claim 2, wherein the first photopolymerizable liquid crystal (A) includes a monofunctional photopolymerizable liquid crystal represented by the following formula (11).
_{^{CH 2 = CR 11 -COO- (L}} 1) a1 -E 11 - (S 1) b1 -E 12 - (T 1) c1 - (E 13) d1 -R 12 ··· (11)
(However, the symbols in the formula have the following meanings.
R ^{11 is a} hydrogen atom or a methyl group.
R ¹² : an alkyl group having 1 to 8 carbon atoms or a fluorine atom (however, in the case of an alkyl group, it may have an etheric oxygen atom between carbon-carbon bonds or at the end bonded to a cyclic group, Some or all of the atoms may be substituted with fluorine atoms.)
L ¹ : It may have an etheric oxygen atom between carbon-carbon bonds, a part or all of hydrogen atoms may be substituted with fluorine atoms, and COO is bonded to the position where E ¹¹ is bonded. , OCO or O, optionally having 1 to 8 carbon atoms.
E ¹¹ , E ¹² and E ¹³ : each independently a trans-1,4-cyclohexylene group or a trans-2,6-decahydronaphthalene group (provided that a hydrogen atom bonded to a carbon atom in the group is a fluorine atom or It may be substituted with a methyl group).
S ¹ and T ¹ : each independently —OCO—, —COO—, — (CH ₂ ) ₂ —, —CH ₂ O—, —OCH ₂ — or a single bond.
a1, b1, c1 and d1: each independently 0 or 1. ) The photopolymerizable liquid crystal composition according to claim 2, wherein the first photopolymerizable liquid crystal (A) includes a bifunctional photopolymerizable liquid crystal represented by the following formula (12).
_{^{CH 2 = CR 21 -COO- (L}} 2) a2 -E 21 - (S 2) b2 -E 22 - (T 2) c2 - (E 23) d2 - (M 2) e2 -OCO-CR 22 = CH ₂ ... (12)
(However, the symbols in the formula have the following meanings.
R ²¹ and R ²² : each independently a hydrogen atom or a methyl group.
L ² : It may have an etheric oxygen atom between carbon-carbon bonds, a part or all of hydrogen atoms may be substituted with fluorine atoms, and COO is bonded to the position where E ²¹ is bonded. , OCO or O, optionally having 1 to 8 carbon atoms.
M ² : It may have an etheric oxygen atom between carbon-carbon bonds, a part or all of hydrogen atoms may be substituted with fluorine atoms, and COO is bonded to the position where E ²³ is bonded. , OCO or O, optionally having 1 to 8 carbon atoms.
E ²¹ , E ²² and E ²³ : each independently a trans-1,4-cyclohexylene group or a trans-2,6-decahydronaphthalene group (provided that a hydrogen atom bonded to a carbon atom in the group is a fluorine atom or It may be substituted with a methyl group).
S ² and T ² : each independently —OCO—, —COO—, — (CH ₂ ) ₂ —, —CH ₂ O—, —OCH ₂ — or a single bond.
a2, b2, c2, d2 and e2: each independently 0 or 1. ) The photopolymerizable liquid crystal composition according to any one of claims 1 to 4, wherein the second photopolymerizable liquid crystal (B) is represented by the following formula (20).
^{Q 1 -Z 1 -A 1 -Z 3} -M-Z 4 -A 2 -Z 2 -Q 2 ··· (20)
(However, the symbols in the formula have the following meanings.
Q ¹ and Q ² : each independently a photopolymerization reactive group.
Z ¹ , Z ² , Z ³ and Z ⁴ : each independently a single bond or a divalent linking group.
A ¹ and A ² : each independently a spacer group having 2 to 20 carbon atoms.
M: mesogenic group containing an aromatic ring) The photopolymerizable liquid crystal composition according to claim 5, wherein the second photopolymerizable liquid crystal (B) includes a photopolymerizable liquid crystal represented by the following formula (21).
_{^{CH 2 = CR 41 -COO- (E}} 41) m4 -Cy-Y 4 -Cy- (E 42) n4 -OCO-CR 42 = CH 2 ··· (21)
(However, the symbols in the formula have the following meanings.
R ⁴¹ and R ⁴² each independently represents a hydrogen atom or a methyl group.
Y ⁴ : —OCO— or —COO—.
m4 and n4: each independently 0 or 1 (except when both are 0).
E ⁴¹ and E ⁴² : each independently 1,4-phenylene group or trans-1,4-cyclohexylene group. However, at least one of E ⁴¹ and E ⁴² is a 1,4-phenylene group.
Cy: trans-1,4-cyclohexylene group. However, in the 1,4-phenylene group and trans-1,4-cyclohexylene group, the hydrogen atom in the group may be substituted with a fluorine atom, a chlorine atom or a methyl group. ) The photopolymerizable liquid crystal composition according to claim 5, wherein the second photopolymerizable liquid crystal (B) includes a photopolymerizable liquid crystal represented by the following formula (22).
_{^{CH 2 = CR 51 -COO- (L}} 5) k5 -E 51 -E 52 -E 53 -E 54 - (M 5) n5 -OCO-CR 52 = CH 2 ··· (22)
(However, the symbols in the formula have the following meanings.
R ⁵¹ and R ⁵² : each independently a hydrogen atom or a methyl group.
k5 and n5: each independently 0 or 1.
L ⁵ :-( CH _{2) p5} O- or - (CH _{2) p5} - (wherein, p5 2-8 integer)..
M ⁵ : —O (CH ₂ ) _p5 — or — (CH ₂ ) _p5 — (wherein p5 is an integer of 2 to 8).
E ⁵¹ : 1,4-phenylene group.
E ⁵² , E ⁵³ and E ⁵⁴ are each independently 1,4-phenylene group or trans-1,4-cyclohexylene group, and at least one of E ⁵² and E ⁵³ is trans-1,4-cyclohexylene group . However, in the 1,4-phenylene group and trans-1,4-cyclohexylene group, a hydrogen atom bonded to a carbon atom in the group may be substituted with a fluorine atom, a chlorine atom or a methyl group. ) The photopolymerizable liquid crystal composition according to claim 5, wherein the second photopolymerizable liquid crystal (B) includes a photopolymerizable liquid crystal represented by the following formula (23).
_{^{CH 2 = CR 61 -COO- (L}} 6) k6 -E 61 -E 62 -E 63 - (M 6) n6 -OCO-CR 62 = CH 2 ··· (23)
(However, the symbols in the formula have the following meanings.
R ⁶¹ and R ⁶² : each independently a hydrogen atom or a methyl group.
k6 and n6: each independently 0 or 1.
L ⁶ : — (CH ₂ ) _{p 6} O—, —Cy—COO— (Cy is a trans-1,4-cyclohexylene group), or —Cy—OCO— (where p6 is an integer of 2 to 8). ).
M ⁶ : —O (CH ₂ ) _p6 —, —OCO—Cy— (Cy is a trans-1,4-cyclohexylene group), or —COO—Cy— (where p6 is an integer of 2 to 8). ).
E ⁶¹ , E ⁶² and E ⁶³ : each independently 1,4-phenylene group or trans-1,4-cyclohexylene group. However, at least one of E ⁶¹ , E ⁶² and E ⁶³ is a 1,4-phenylene group, and at least one is a trans-1,4-cyclohexylene group. In the case where L ⁶ is —Cy—OCO—, E ⁶¹ is a trans-1,4-cyclohexylene group, and L ⁶ is — (CH ₂ ) _p6 O— or k6 is 0. Each of E ⁶¹ and E ^{63 in} the above is a 1,4-phenylene group, and E ⁶² is a trans-1,4-cyclohexylene group). However, in the 1,4-phenylene group and trans-1,4-cyclohexylene group, a hydrogen atom bonded to a carbon atom in the group may be substituted with a fluorine atom, a chlorine atom or a methyl group. ) The photopolymerizable liquid crystal composition according to claim 5, wherein the second photopolymerizable liquid crystal (B) includes a photopolymerizable liquid crystal represented by the following formula (24).
_{^{CH 2 = CR 71 -COO- (L}} 7) k7 -Ph- (X 7) -Ph- (Y 7) -Ph- (M 7) n7 -OCO-CR 72 = CH 2 ··· (24)
(However, the symbols in the formula have the following meanings.
R ⁷¹ and R ⁷² : each independently a hydrogen atom or a methyl group.
X ⁷ and Y ⁷ are each independently —OCO— or —COO—.
_{^{L 7 :-( CH 2) p7 O}} -, - (CH 2) p7 O-COO -, - (CH 2) p7 OCO- or _{- (CH} 2) p7 COO- (wherein, p7 is of 2-8 integer.).
M ⁷ : —O (CH ₂ ) _{p 7} —, OCO—O (CH ₂ ) _{p 7} —, —OCO— (CH ₂ ) _{p 7} or —COO (CH ₂ ) _{p 7} — (where p 7 is an integer of 2 to 8) .)
k7 and n7: each independently 0 or 1. Ph: 1,4-phenylene group. However, in the 1,4-phenylene group, a hydrogen atom bonded to a carbon atom in the group may be substituted with a fluorine atom, a chlorine atom or a methyl group. )   The optical compensation film which shows positive uniaxial anisotropy formed by photocuring the coating film of the photopolymerizable liquid crystal composition in any one of Claims 1-9.   An optical compensation laminated film comprising: an optical compensation film exhibiting negative uniaxial anisotropy; and an optical compensation film exhibiting positive uniaxial anisotropy according to claim 10 laminated on the optical compensation film.   The optical compensation laminated film according to claim 11, wherein the optical compensation film exhibiting negative uniaxial anisotropy includes polyimide having an aliphatic ring in a skeleton.   An electrode substrate comprising the optical compensation laminated film according to claim 12 and an electrode formed on the optical compensation laminated film on a substrate.   A substrate for a liquid crystal display device, comprising the electrode substrate according to claim 13 and an alignment film formed on the electrode substrate.   A liquid crystal display device comprising: the liquid crystal substrate according to claim 14; a counter substrate; and a liquid crystal layer sandwiched between the liquid crystal substrate and the counter substrate.

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