JP7461122B2 - Laminate and elliptically polarizing plate including same - Google Patents

Description

The present invention relates to a laminate including a horizontally aligned liquid crystal cured film, an adhesive layer and a vertically aligned liquid crystal cured film, and an elliptically polarizing plate including the laminate.

An elliptically polarizing plate is an optical member in which a polarizing plate and a retardation plate are laminated.For example, in a device that displays an image in a flat state, such as an organic EL image display device, the elliptically polarizing plate is used to prevent light reflection at the electrodes that constitute the device. It is used to prevent A so-called λ/4 plate is generally used as a retardation plate constituting this elliptically polarizing plate. As such a retardation plate, a retardation plate made of a horizontally oriented liquid crystal cured film in which a polymerizable liquid crystal compound is polymerized and cured while oriented horizontally with respect to the plane of the retardation plate is known. . In addition, there is a demand for an elliptically polarizing plate that has an optical compensation function to exhibit the same optical performance when viewed from an oblique direction as when viewed from the front. A retardation plate has been proposed that further includes a vertically aligned liquid crystal cured film in which a liquid crystal compound is polymerized and cured in a state in which the liquid crystal compound is oriented in a direction perpendicular to the plane of the retardation plate (Patent Document 1).

Japanese Patent Application Publication No. 2015-163935

In a conventional elliptical polarizing plate including a horizontally aligned liquid crystal cured film and a vertically aligned liquid crystal cured film, the horizontally aligned liquid crystal cured film and the vertically aligned liquid crystal cured film are generally laminated via an adhesive layer. In such an elliptical polarizing plate, interfacial reflections are likely to occur at the interface between the horizontally aligned liquid crystal cured film and the adhesive layer, and at the interface between the adhesive layer and the vertically aligned liquid crystal cured film, and these interfacial reflections may interfere with each other, causing interference unevenness. Interference unevenness can cause reduced visibility when the elliptical polarizing plate is used in a display such as an image display device.

An object of the present invention is to provide a laminate in which interference unevenness due to reflection at each interface of a horizontally aligned liquid crystal cured film, an adhesive layer, and a vertically aligned liquid crystal cured film is less likely to occur.

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, the present invention includes the following aspects.
[1] Including a horizontally aligned liquid crystal cured film, an adhesive layer and a vertically aligned liquid crystal cured film in this order,
A laminate in which the in-plane refractive index of the pressure-sensitive adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film satisfy the relationship of formula (1).
|((n2x+n2y)/2)-((n3x+n3y)/2)|≦0.03 (1)
[In formula (1), n2x represents the refractive index at wavelength λnm in the direction that produces the maximum refractive index within the plane of the adhesive layer, and n2y is within the same plane as n2x and perpendicular to the direction of n2x. n3x represents the refractive index at wavelength λnm in the direction in which the maximum refractive index occurs in the plane of the vertically aligned liquid crystal cured film, and n3y represents the refractive index at wavelength λnm in the direction in which the maximum refractive index occurs in the plane of the vertically aligned liquid crystal cured film. It represents the refractive index at a wavelength λ nm in a direction perpendicular to the direction. ]
[2] The laminate according to [1] above, wherein the horizontally aligned liquid crystal cured film satisfies formulas (2) and (3).
Re(450)/Re(550)≦1.00 (2)
100nm<Re(550)<160nm (3)
[In the formula, Re (λ) represents an in-plane retardation value of a horizontally aligned liquid crystal cured film at a wavelength of λ nm. ]
[3] The laminate according to [1] or [2] above, wherein the vertically aligned liquid crystal cured film satisfies formulas (4) and (5).
n3x≒n3y<n3z (4)
-150nm<Rth(550)<-30nm (5)
[In formula (4), n3x represents the refractive index at wavelength λnm in the direction that produces the maximum refractive index in the plane of the vertically aligned liquid crystal cured film, and n3y is the refractive index in the same plane as n3x and perpendicular to the direction of n3x. n3z represents the refractive index at wavelength λnm in the direction of the vertical alignment liquid crystal cured film, and ≒ represents the refractive index at wavelength λnm in the film thickness direction of the vertically aligned liquid crystal cured film, and ≒ represents that the difference in the refractive index between the two is 0.01 or less. ,
In formula (5), Rth (550) represents the retardation value in the thickness direction at a wavelength of 550 nm of the vertically aligned liquid crystal cured film. ]
[4] The laminate according to any one of [1] to [3] above, wherein the adhesive layer has a thickness of 0.1 μm or more and 2 μm or less.
[5] An elliptically polarizing plate formed by laminating the laminate according to any one of [1] to [4] above and a polarizing film.

According to the present invention, it is possible to provide a laminate in which interference unevenness due to reflection at each interface of a horizontally aligned liquid crystal cured film, an adhesive layer, and a vertically aligned liquid crystal cured film is unlikely to occur.

The laminate of the present invention includes a horizontally aligned liquid crystal cured film, an adhesive layer, and a vertically aligned liquid crystal cured film in this order. In the laminate of the present invention, the in-plane refractive index of the adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film satisfy the relationship of formula (1).
|((n2x+n2y)/2)-((n3x+n3y)/2)|≦0.03 (1)
In formula (1), n2x represents the refractive index at wavelength λ nm in the direction that produces the maximum refractive index in the plane of the adhesive layer, and n2y is perpendicular to the direction of n2x in the same plane as n2x. It represents the refractive index at wavelength λ nm in the direction. n3x represents the refractive index at wavelength λnm in the direction that produces the maximum refractive index in the plane of the vertically aligned liquid crystal cured film, and n3y represents the refractive index at wavelength λnm in the direction perpendicular to the direction of n3x in the same plane as n3x. Represents refractive index.

The formula (1) means that the difference between the in-plane refractive index of the adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film is 0.03 or less, that is, the difference is small.
In a laminate formed by laminating a horizontally aligned liquid crystal cured film, a pressure-sensitive adhesive layer, and a vertically aligned liquid crystal cured film in this order, interfacial reflection is likely to occur at the interface between the horizontally aligned liquid crystal cured film and the pressure-sensitive adhesive layer, and at the interface between the pressure-sensitive adhesive layer and the vertically aligned liquid crystal cured film. The interfacial reflection occurring at the interface between each liquid crystal cured film and the pressure-sensitive adhesive layer constituting such a laminate is caused by the difference between the refractive index of each liquid crystal cured film and the refractive index of the pressure-sensitive adhesive layer, and the interfacial reflection between the horizontally aligned liquid crystal cured film and the pressure-sensitive adhesive layer interferes with each other, and interference unevenness is likely to occur. In the laminate of the present invention, the difference between the in-plane refractive index of the pressure-sensitive adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film satisfies the relationship of the above formula (1), so that interfacial reflection between the pressure-sensitive adhesive layer and the vertically aligned liquid crystal cured film is unlikely to occur, and thus interference unevenness occurring due to interference with the interfacial reflection between the horizontally aligned liquid crystal cured film and the pressure-sensitive adhesive layer can be suppressed.

In order to suppress interference unevenness that occurs in a laminate composed of a horizontally aligned liquid crystal cured film, an adhesive layer, and a vertically aligned liquid crystal cured film, it is necessary to It is also conceivable to reduce the difference in in-plane refractive index. However, since a slow axis and a fast axis exist in the plane of the horizontally aligned liquid crystal cured film, the difference between the in-plane refractive index of the adhesive layer and the in-plane refractive index of the horizontally aligned liquid crystal cured film is Even if it is made smaller, interference unevenness can be suppressed in the direction where the refractive index of the adhesive layer and the refractive index of the adhesive layer are small within the plane of the horizontally aligned liquid crystal cured film. There are directions in which the difference is large, and it is difficult to suppress interference unevenness in such directions. On the other hand, while a vertically aligned liquid crystal cured film generally has a large refractive index in the film thickness direction (perpendicular to the surface of the liquid crystal cured film), the refractive index within the plane of the vertically aligned liquid crystal cured film is almost negligible. Since there is no difference, by reducing the difference in in-plane refractive index between the adhesive layer and the vertically aligned liquid crystal cured film, it is possible to suppress the occurrence of interference unevenness over the entire in-plane area of the laminate.

In the laminate of the present invention, the difference (absolute value) between the in-plane refractive index of the adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film [|((n2x+n2y)/2)-((n3x+n3y)/ 2) value of |] is 0.03 or less, preferably 0.025 or less, more preferably 0.02 or less. Although the lower limit of the difference is not particularly limited, the difference in the in-plane refractive index is ideally 0 from the viewpoint that the smaller the difference is, the more likely the effect of suppressing interference unevenness is to improve.

The difference between the in-plane refractive index of the adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film can be controlled by appropriately selecting the type of adhesive forming the adhesive layer and the type of polymerizable liquid crystal compound constituting the vertically aligned liquid crystal cured film, the composition of the polymerizable liquid crystal composition, etc., to adjust the in-plane refractive index of the adhesive layer and/or the in-plane refractive index of the vertically aligned liquid crystal cured film. In particular, by adjusting the in-plane refractive index of the adhesive layer that does not have light absorption anisotropy to approximate the in-plane refractive index of the vertically aligned liquid crystal cured film, it is possible to effectively suppress interfacial reflection occurring at the interface between the adhesive layer and the vertically aligned liquid crystal cured film while ensuring the high optical properties required of an optical film.

The horizontally aligned liquid crystal cured film constituting the laminate of the present invention preferably satisfies formulas (2) and (3).
Re(450)/Re(550)≦1.00 (2)
100nm<Re(550)<160nm (3)
In formulas (2) and (3), Re (λ) represents an in-plane retardation value of a horizontally aligned liquid crystal cured film at a wavelength of λ nm.

When the horizontally aligned liquid crystal cured film satisfies formula (2), the horizontally aligned liquid crystal cured film exhibits so-called reverse wavelength dispersion, in which the in-plane retardation value at a short wavelength is smaller than the in-plane retardation value at a long wavelength. When the horizontally aligned liquid crystal cured film exhibits reverse wavelength dispersion, it tends to exhibit uniform retardation performance over a wide wavelength range of visible light, and the optical properties of the laminate are likely to be improved. On the other hand, in a liquid crystal cured film exhibiting reverse wavelength dispersion, the refractive index tends to be high in order to obtain the properties, and as a result, a difference with the refractive index of the adhesive layer is likely to occur, and interference unevenness is likely to appear more prominently. Even in such a case, in the present invention, by controlling the difference between the refractive index of the vertically aligned liquid crystal cured film and the refractive index of the adhesive layer, it is possible to effectively suppress the interfacial reflection at the interface between the vertically aligned liquid crystal cured film and the adhesive layer, and therefore it is possible to obtain a laminate that is less likely to cause interference unevenness while ensuring the high optical properties that can be expressed by a liquid crystal cured film exhibiting reverse wavelength dispersion.

Re(450)/Re(550) is preferably 0.70 or more, more preferably is 0.78 or more, and preferably 0.95 or less, more preferably 0.92 or less.

The in-plane retardation value can be adjusted by the thickness d1 of the horizontally aligned liquid crystal cured film. The in-plane retardation value of the horizontally aligned liquid crystal cured film is determined by the formula Re1(λ)=(n1x(λ)-n1y(λ))×d1 (where n1x represents the refractive index at a wavelength of λ nm in the direction that produces the maximum refractive index in the plane of the horizontally aligned liquid crystal cured film, n1y represents the refractive index at a wavelength of λ nm in the same plane as n1x and in the direction perpendicular to the direction of n1x, and d1 represents the film thickness of the horizontally aligned liquid crystal cured film). To obtain the desired in-plane retardation value (Re1(λ): the in-plane retardation value of the horizontally aligned liquid crystal cured film at a wavelength λ (nm)), it is sufficient to adjust the three-dimensional refractive index and the film thickness d1.

When the horizontally aligned liquid crystal cured film satisfies formula (3), the front reflection hue during black display tends to improve when a laminate (elliptically polarizing plate) containing the horizontally aligned liquid crystal cured film is applied to an organic EL display device. A more preferable range of the in-plane retardation value is 130 nm≦ReA(550)≦150 nm.

The vertically aligned liquid crystal cured film constituting the laminate of the present invention preferably satisfies the formulae (4) and (5).
n3x ≒ n3y < n3z (4)
−150 nm < Rth(550) < −30 nm (5)
In formula (4), n3x represents the refractive index at a wavelength of λ nm in the direction in which the maximum refractive index occurs in the plane of the vertically aligned liquid crystal cured film, n3y represents the refractive index at a wavelength of λ nm in the direction perpendicular to the direction of n3x in the same plane as n3x, n3z represents the refractive index at a wavelength of λ nm in the thickness direction of the vertically aligned liquid crystal cured film, and ≒ represents that the difference between the two refractive indices is 0.01 or less. In formula (5), Rth(550) represents the retardation value in the thickness direction of the vertically aligned liquid crystal cured film at a wavelength of 550 nm.

Equation (4) shows that the refractive index (n3z) at wavelength λnm in the thickness direction of the vertically aligned liquid crystal cured film is larger than the refractive index (n3x and n3y) at wavelength λnm in the plane of the vertically aligned liquid crystal cured film, and n3x and The difference from n3y is 0.01 or less, which means that there is almost no difference in refractive index within the plane of the vertically aligned liquid crystal cured film. A vertically aligned liquid crystal cured film that satisfies formula (4) has no in-plane refractive index difference or has a very small in-plane refractive index difference; This makes it difficult for local deviations between the in-plane refractive index of the pressure-sensitive adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film to occur as a result. Thereby, by controlling the difference between the in-plane refractive index of the adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film so as to satisfy the relationship of formula (1) above, the adhesive layer and Interfacial reflection between the vertically aligned liquid crystal cured films is less likely to occur, and the effect of suppressing the occurrence of interference unevenness over the entire in-plane area of the laminate is more likely to be improved.

When the vertically aligned liquid crystal cured film satisfies formula (5), the polymerizable liquid crystal compound constituting the vertically aligned liquid crystal cured film is oriented with a high degree of order in the vertical direction of the liquid crystal cured film, and when a laminate including the vertically aligned liquid crystal cured film is incorporated into an organic EL display device, the laminate tends to have an excellent effect of suppressing oblique reflection hue change during black display. From the viewpoint of further improving the optical properties of the laminate, the retardation value Rth(550) in the thickness direction of the vertically aligned liquid crystal cured film is more preferably -100 nm or more, even more preferably -90 nm or more, and more preferably -40 nm or less, even more preferably -50 nm or less.

The retardation value Rth (λ) in the film thickness direction of the vertically aligned liquid crystal cured film can be adjusted by the thickness d3 of the vertically aligned liquid crystal cured film. The in-plane phase difference value is calculated using the following formula:
Rth(λ)=((n3x(λ)+n3y(λ))/2-n3z(λ))×d3
(In the formula, n3x(λ), n3y(λ) and n3z(λ) have the same meanings as above)
Therefore, in order to obtain a desired retardation value Rth(λ) in the film thickness direction, the three-dimensional refractive index and the film thickness d3 may be adjusted.

In the laminate of the present invention, the horizontally aligned liquid crystal cured film, the adhesive layer, and the vertically aligned liquid crystal cured film may be laminated via other layers, but it is preferable that the adhesive layer and the vertically aligned liquid crystal cured film are adjacent to each other. When the adhesive layer and the vertically aligned liquid crystal cured film are adjacent to each other, interference unevenness can be reduced by controlling the difference between the in-plane refractive index of the adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film without being affected by the in-plane refractive index derived from other layers. Furthermore, in order to suppress interfacial reflection that may occur in the relationship with the adhesive layer and the horizontally aligned liquid crystal cured film, it is more preferable that the horizontally aligned liquid crystal cured film and the adhesive layer, and the adhesive layer and the vertically aligned liquid crystal cured film are adjacent to each other.
Examples of the other layers include a horizontal alignment film, a vertical alignment film, and a cured resin layer such as a protective layer or a hard coat layer.

In the present invention, the horizontally aligned liquid crystal cured film and the horizontally aligned liquid crystal cured film each consist of a cured product of a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound. The polymerizable liquid crystal compound is not particularly limited as long as it can form a liquid crystal cured film having the desired optical properties, and any polymerizable liquid crystal compound conventionally known in the field of retardation films can be used.

The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. Generally, the polymer (cured product) obtained by polymerizing the polymerizable liquid crystal compound alone in a state aligned in a specific direction includes a polymerizable liquid crystal compound exhibiting positive wavelength dispersion and a polymerizable liquid crystal compound exhibiting reverse wavelength dispersion. In the present invention, only one type of polymerizable liquid crystal compound may be used, or both types of polymerizable liquid crystal compounds may be mixed and used. In addition, the polymerizable liquid crystal compound constituting the horizontally aligned liquid crystal cured film and the polymerizable liquid crystal compound constituting the vertically aligned liquid crystal cured film may be the same or different. From the viewpoint of easily obtaining a liquid crystal cured film satisfying the above formula (2) and easily improving the optical properties of the laminate, it is preferable that the horizontally aligned liquid crystal cured film in the laminate of the present invention is a cured product of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound exhibiting reverse wavelength dispersion.

The polymerizable group refers to a group that can participate in a polymerization reaction. In the present invention, the polymerizable group possessed by the polymerizable liquid crystal compound that forms the liquid crystal cured film is preferably a photopolymerizable group. The photopolymerizable group refers to a polymerizable group that can participate in a polymerization reaction by a reactive species generated from a photopolymerization initiator, such as an active radical or an acid. Examples of the photopolymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferred, and an acryloyloxy group is more preferred. The liquid crystallinity exhibited by the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, but a thermotropic liquid crystal is preferred in terms of the ability to precisely control the film thickness. In addition, the phase order structure in the thermotropic liquid crystal may be nematic, smectic, or discotic. The polymerizable liquid crystal compounds may be used alone or in combination of two or more.

Polymerizable liquid crystal compounds with so-called T-shaped or H-shaped molecular structures tend to exhibit reverse wavelength dispersion, and polymerizable liquid crystal compounds with T-shaped molecular structures tend to exhibit even stronger reverse wavelength dispersion.

The polymerizable liquid crystal compound exhibiting reverse wavelength dispersion is preferably a compound having the following characteristics (A) to (D).
(A) A compound capable of forming a nematic phase or a smectic phase.
(B) The polymerizable liquid crystal compound has π electrons in the long axis direction (a).
(C) It has π electrons in a direction intersecting with the long axis direction (a) [intersecting direction (b)].
(D) A π electron density in the long axis direction (a) of a polymerizable liquid crystal compound defined by the following formula (i), where N(πa) is the total number of π electrons present in the long axis direction (a) and N(Aa) is the total number of molecular weights present in the long axis direction:
D(πa)=N(πa)/N(Aa) (i)
The total number of π electrons present in the cross direction (b) is N(πb), and the total number of molecular weights present in the cross direction (b) is N(Ab), where N(πb) is the total number of π electrons present in the cross direction (b), and N(Ab) is the total number of molecular weights present in the cross direction (b), the π electron density in the cross direction (b) of the polymerizable liquid crystal compound is defined by the following formula (ii):
D(πb)=N(πb)/N(Ab) (ii)
and the formula (iii)
0≦[D(πa)/D(πb)]<1 (iii)
[i.e., the π electron density in the intersecting direction (b) is greater than the π electron density in the long axis direction (a)]. As described above, a polymerizable liquid crystal compound having π electrons on the long axis and in the direction intersecting therewith generally tends to have a T-shaped structure.

In the features (A) to (D) above, the major axis direction (a) and the number N of π electrons are defined as follows.
- For example, in the case of a compound having a rod-like structure, the long axis direction (a) is the long axis direction of the rod.
- The number of π electrons N (πa) existing in the major axis direction (a) does not include π electrons that disappear due to polymerization reaction.
・The number N (πa) of π electrons existing on the long axis direction (a) is the total number of π electrons on the long axis and π electrons conjugated with this, for example, the number N (πa) existing on the long axis direction (a). It includes the number of π electrons present in a ring that satisfies Huckel's rule.
- The number of π electrons N (πb) existing in the cross direction (b) does not include π electrons that disappear due to the polymerization reaction.
A polymerizable liquid crystal compound that satisfies the above has a mesogenic structure in the long axis direction. This mesogenic structure develops a liquid crystal phase (nematic phase, smectic phase).

A nematic phase or a smectic phase can be formed by heating a polymerizable liquid crystal compound satisfying the above (A) to (D) above the phase transition temperature. In the nematic phase or smectic phase formed by aligning this polymerizable liquid crystal compound, the long axes of the polymerizable liquid crystal compound are usually oriented parallel to each other, and the long axis direction is the nematic phase or smectic phase. is the orientation direction. When such a polymerizable liquid crystal compound is formed into a film and polymerized in a nematic phase or smectic phase, a polymer film consisting of polymers oriented in the long axis direction (a) can be formed. . This polymer film absorbs ultraviolet light by π electrons in the major axis direction (a) and π electrons in the cross direction (b). Here, the absorption maximum wavelength of ultraviolet rays absorbed by π electrons in the cross direction (b) is assumed to be λbmax. λbmax is typically 300 nm to 400 nm. The density of π electrons satisfies the above formula (iii), and since the π electron density in the cross direction (b) is larger than the π electron density in the major axis direction (a), there is a vibration plane in the cross direction (b). The polymer film has a larger absorption of linearly polarized ultraviolet rays (wavelength: λbmax) having a wavelength of λbmax than that of linearly polarized ultraviolet rays (wavelength: λbmax) having a vibration plane in the major axis direction (a). The ratio (ratio of absorbance in the cross direction (b) of linearly polarized ultraviolet light/absorbance in the major axis direction (a)) is, for example, more than 1.0, preferably 1.2 or more, and usually 30 or less, for example, 10 or less. It is.

Generally, the polymerizable liquid crystal compound having the above characteristics is often one that exhibits reverse wavelength dispersion in the birefringence of the polymer when polymerized in a state aligned in one direction.Specific examples thereof include a compound represented by the following formula (X) (hereinafter, also referred to as "polymerizable liquid crystal compound (X)").

In formula (X), Ar represents a divalent group having an aromatic group which may have a substituent. Examples of the aromatic group include the groups exemplified by (Ar-1) to (Ar-23) described later. Ar may have two or more aromatic groups. The aromatic group may contain at least one of a nitrogen atom, an oxygen atom, and a sulfur atom. When Ar contains two or more aromatic groups, the two or more aromatic groups may be bonded to each other via a divalent bonding group such as a single bond, -CO-O-, or -O-.
G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein a hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with 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, and a carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom.
L ¹ , L ² , B ¹ and B ² each independently represent a single bond or a divalent linking group.
k and l each independently represent an integer of 0 to 3, and satisfy the relationship 1≦k+l, where, when 2≦k+l, B ¹ and B ² , G ¹ and G ² may be the same as or different from each other.
^E1 and ^E2 each independently represent an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms. In addition, a hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and -CH ₂ - contained in the alkanediyl group may be substituted with -O-, -S-, or -C(═O)-.
^P1 and ^P2 each 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 a 1,4-phenylenediyl group 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, or a 1,4-cyclohexanediyl group 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 a 1,4-phenylenediyl group substituted with a methyl group, an unsubstituted 1,4-phenylenediyl group, or an unsubstituted 1,4-trans-cyclohexanediyl group, and particularly preferably an unsubstituted 1,4-phenylenediyl group, or an unsubstituted 1,4-trans-cyclohexanediyl group.
In addition, at least one of a plurality of ^G1s and ^G2s is preferably a divalent alicyclic hydrocarbon group, and more preferably at least one of ^G1s and ^G2s bonded to ^L1 or ^L2 is a divalent 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 - be. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent a single bond, -CH ₂ -, or -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-.

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 - be. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 each independently represent a single bond, -CH ₂ -, or -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 -. be.

From the viewpoint of expressing reverse 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. k=2 and l=2 are preferable because they result in a symmetrical structure.

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 group, and oxiranyl group. , and oxetanyl group. Among these, acryloyloxy group, methacryloyloxy group, vinyl group and vinyloxy group are preferred, and acryloyloxy group and methacryloyloxy group are more preferred.

Ar preferably has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and the like, with benzene rings and naphthalene rings being preferred. The aromatic heterocycles 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, a triazine ring, a pyrroline ring, an imidazole ring, and a pyrazole ring. , thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring. Among these, it is preferable to have a thiazole ring, benzothiazole ring, or benzofuran ring, and more preferably to have a benzothiazole ring. Further, when Ar includes a nitrogen atom, it is preferable that the nitrogen atom has π electrons.

In formula (X), the total number _Nπ of π electrons possessed by the group represented by Ar is usually 6 or more, preferably 8 or more, more preferably 10 or more, even more preferably 14 or more, and particularly preferably 16 or more. In addition, it is preferably 32 or less, more preferably 26 or less, and even more preferably 24 or less.

Examples of the aromatic group contained in Ar include the following groups.

In formulas (Ar-1) to (Ar-23), the mark * represents a connecting part, and Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 12 carbon atoms. group, 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, alkoxy group having 1 to 12 carbon atoms, Alkylthio group having 1 to 12 carbon atoms, N-alkylamino group having 1 to 12 carbon atoms, N,N-dialkylamino group having 2 to 12 carbon atoms, N-alkylsulfamoyl group having 1 to 12 carbon atoms, or carbon Represents an N,N-dialkylsulfamoyl group having numbers 2 to 12. Moreover, Z ⁰ , Z ¹ and Z ² may contain a polymerizable group.

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 represent 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; 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 anthryl group, a phenanthryl group and a biphenyl group, with a phenyl group and a naphthyl group being preferred, and a phenyl group being more preferred. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 4 to 20 carbon atoms and containing at least one heteroatom, such as a nitrogen atom, an oxygen atom or a sulfur atom, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group, with a furyl group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group being preferred.

Y ¹ , Y ² and Y ³ may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a fused polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group refers to a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

Z ⁰ , Z ¹ and Z ² are preferably each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, or an alkoxy group having 1 to 12 carbon atoms; ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group. Moreover, Z ⁰ , Z ¹ and Z ² may contain a polymerizable group.

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

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

In formulas (Ar-16) to (Ar-23), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . Examples of the aromatic heterocyclic group include those mentioned above as aromatic heterocycles that Ar may have, such as a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, and an indole ring. ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring, etc. This aromatic heterocyclic group may have a substituent. Further, Y ¹ may be the aforementioned optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group, together with the nitrogen atom to which it is bonded and Z ⁰ . Examples include a benzofuran ring, a benzothiazole ring, a benzoxazole ring, and the like.

In the present invention, as the polymerizable liquid crystal compound forming the liquid crystal cured film, for example, a compound containing a group represented by the following formula (Y) (hereinafter also referred to as "polymerizable liquid crystal compound (Y)") may be used. . The polymerizable liquid crystal compound (Y) generally tends to exhibit positive wavelength dispersion. These polymerizable liquid crystal compounds can be used alone or in combination of two or more.

P11-B11-E11-B12-A11-B13- (Y)
[In formula (Y), P11 represents a polymerizable group.
A11 represents a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group.
B11 is -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -CO-NR ¹⁶ -, -NR ¹⁶ -CO-, -CO-, - CS- or a single bond. R ¹⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
B12 and B13 each independently represent -C≡C-, -CH=CH-, -CH ₂ -CH ₂ -, -O-, -S-, -C(=O)-, -C(=O ) -O-, -OC(=O)-, -OC(=O)-O-, -CH=N-, -N=CH-, -N=N-, -C(=O ) -NR ¹⁶ -, -NR ¹⁶ -C(=O)-, -OCH ₂ -, -OCF ₂ -, -CH ₂ O-, -CF ₂ O-, -CH=CH-C(=O)- Represents O-, -OC(=O)-CH=CH-, -H, -C≡N or a single bond.
E11 represents an alkanediyl group having 1 to 12 carbon atoms, the hydrogen atom contained in the alkanediyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms, and the hydrogen atom contained in the alkoxy group may be substituted with a halogen atom. Furthermore, -CH ₂ - constituting the alkanediyl group may be replaced with -O- or -CO-. ]

The number of carbon atoms in the aromatic hydrocarbon group and the alicyclic hydrocarbon group of A11 is preferably in the range of 3 to 18, more preferably in the range of 5 to 12, particularly 5 or 6. preferable. The hydrogen atoms contained in the divalent alicyclic hydrocarbon group and the divalent aromatic hydrocarbon group represented by A11 include a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, It may be substituted with a cyano group or a nitro group, and the hydrogen atom contained in the alkyl group having 1 to 6 carbon atoms and the alkoxy group having 1 to 6 carbon atoms may be substituted with a fluorine atom. As A11, cyclohexane-1,4-diyl group and 1,4-phenylene group are preferable.

E11 is preferably a linear alkanediyl group having 1 to 12 carbon atoms. --CH ₂ -- constituting the alkanediyl group may be replaced with --O--.
Specific examples of such alkyl groups include linear alkanediyl groups having 1 to 12 carbon atoms, such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane- _1,9 -diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, and a dodecane-1,12-diyl group; -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -, -CH 2 -CH ₂ -O-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ - and -CH ₂ -CH ₂ -O-CH 2 -CH ₂ -O-CH ₂ -CH _{2 -O} -CH ₂ -CH _{2 -} --etc.
As B11, --O--, --S--, --CO--O-- and --O--CO-- are preferable, and among them, --CO--O-- is more preferable.
As B12 and B13, each independently is preferably -O-, -S-, -C(=O)-, -C(=O)-O-, -O-C(=O)- or -O-C(=O)-O-, and among these, -O- or -O-C(=O)-O- is more preferable.

［式（Ｐ－１１）～（Ｐ－１５）中、
Ｒ^１７～Ｒ^２１はそれぞれ独立に、炭素数１～６のアルキル基または水素原子を表わす。］ As the polymerizable group represented by P11, a radical polymerizable group or a cationically polymerizable group is preferable from the viewpoint of high polymerization reactivity, particularly high photopolymerization reactivity. In addition, the polymerizable group is preferably a group represented by the following formulae (P-11) to (P-15), since the handling is easy and the liquid crystal compound is easily produced.

[In formulas (P-11) to (P-15),
R ¹⁷ to R ²¹ each independently represent an alkyl group having 1 to 6 carbon atoms or a hydrogen atom.]

Specific examples of the groups represented by formulae (P-11) to (P-15) include groups represented by the following formulae (P-16) to (P-20).

P11 is preferably a group represented by formula (P-14) to formula (P-20), and more preferably a vinyl group, p-stilbene group, epoxy group or oxetanyl group.
More preferably, the group represented by P11-B11- is an acryloyloxy group or a methacryloyloxy group.

Examples of the polymerizable liquid crystal compound (Y) include compounds represented by formula (I), formula (II), formula (III), formula (IV), formula (V) or formula (VI).
P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-B16-E12-B17-P12 (I)
P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-F11 (II)
P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-E12-B17-P12 (III)
P11-B11-E11-B12-A11-B13-A12-B14-A13-F11 (IV)
P11-B11-E11-B12-A11-B13-A12-B14-E12-B17-P12 (V)
P11-B11-E11-B12-A11-B13-A12-F11 (VI)
[Wherein,
A11, B11 to B13 and P11 are as defined above.
A12 to A14 each independently have the same meaning as A11, B14 to B16 each independently have the same meaning as B12, B17 has the same meaning as B11, E12 has the same meaning as E11, and P12 has the same meaning as P11.
F11 represents a hydrogen atom, an alkyl group having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, a cyano group, a nitro group, a trifluoromethyl group, a dimethylamino group, a hydroxyl group, a methylol group, a formyl group, a sulfo group (--SO ₃ H), a carboxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or a halogen atom, and -CH ₂ - constituting the alkyl group and the alkoxy group may be replaced by -O-.]

Specific examples of the polymerizable liquid crystal compound (Y) include compounds having a polymerizable group among those described in "3.8.6 Network (fully cross-linked type)" and "6.5.1 Liquid crystal material b. Polymerizable nematic liquid crystal material" in Liquid Crystal Handbook (edited by Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. on October 30, 2000), and the polymerizable liquid crystals described in JP-A Nos. 2010-31223, 2010-270108, 2011-6360, and 2011-207765.

Specific examples of the polymerizable liquid crystal compound (Y) include the following formulas (I-1) to (I-4), formula (II-1) to formula (II-4), and formula (III-1) to formula (III-26), represented by formula (IV-1) to formula (IV-26), formula (V-1) to formula (V-2), and formula (VI-1) to formula (VI-6) Examples include compounds. In addition, in the following formula, k1 and k2 each independently represent an integer from 2 to 12. These polymerizable liquid crystal compounds (Y) are preferable in terms of ease of synthesis or availability.

Both of the polymerizable liquid crystal compounds (X) and (Y) can be used either horizontally or vertically.

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, more preferably 85 to 98 parts by mass, and even more preferably 90 to 95 parts by mass, based on 100 parts by mass of the solid content of the polymerizable liquid crystal composition. If the content of the polymerizable liquid crystal compound is within the above range, it is advantageous in terms of the alignment accuracy of the resulting liquid crystal cured film. In addition, when the polymerizable liquid crystal composition contains two or more types of polymerizable liquid crystal compounds, it is preferable that the total amount of all the liquid crystal compounds contained in the polymerizable liquid crystal composition is within the above content range. In addition, in this specification, the solid content of the polymerizable liquid crystal composition means all components excluding volatile components such as organic solvents from the polymerizable liquid crystal composition.

In addition to the polymerizable liquid crystal compound, the polymerizable liquid crystal composition may further contain additives such as a solvent, a polymerization initiator, a leveling agent, an antioxidant, a photosensitizer, and a reactive additive. Each of these components may be used alone or in combination of two or more.

Since the polymerizable liquid crystal composition is usually applied to a base film or the like in a state dissolved in a solvent, it is preferable that the composition contains a solvent. The solvent is preferably a solvent that can dissolve the polymerizable liquid crystal compound, and is preferably a solvent that is inert to the polymerization reaction of the polymerizable liquid crystal compound. Examples of solvents include alcohols such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, 1-methoxy-2-propanol, 2-butoxyethanol, and propylene glycol monomethyl ether. Solvents: Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate and ethyl lactate; Acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone Ketone solvents; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; cycloaliphatic hydrocarbon solvents such as ethylcyclohexane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; such as tetrahydrofuran and dimethoxyethane. Ether solvents; chlorine-containing solvents such as chloroform and chlorobenzene; amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone (NMP), 1,3-dimethyl-2-imidazolidinone, etc. It will be done. These solvents can be used alone or in combination. Among these, from the viewpoint of film coating, it is preferable to use at least one selected from alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents, and aromatic hydrocarbon solvents, and the solubility of the polymerizable liquid crystal compound From this viewpoint, it is more preferable to use at least one selected from ester solvents, ketone solvents, amide solvents, and aromatic hydrocarbon solvents.

The content of the solvent in the polymerizable liquid crystal composition is preferably 50 to 98 parts by weight, more preferably 70 to 95 parts by weight, relative to 100 parts by weight of the polymerizable liquid crystal composition. Therefore, the solid content per 100 parts by weight of the polymerizable liquid crystal composition is preferably 2 to 50 parts by weight. If the solid content is 50 parts by weight or less, the viscosity of the polymerizable liquid crystal composition is low, so that the thickness of the film tends to be approximately uniform and unevenness is less likely to occur. The above solid content can be appropriately determined taking into consideration the thickness of the polymerizable liquid crystal cured film to be produced.

A polymerization initiator is a compound that generates reactive species by the contribution of heat or light and can initiate a polymerization reaction of a polymerizable liquid crystal compound or the like. Examples of the reactive species include radicals, cations, anions, and the like. Among them, from the viewpoint of easy reaction control, a photopolymerization initiator that generates radicals upon irradiation with light is preferred.

Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, oxime compounds, α-hydroxyketone compounds, α-aminoketone compounds, triazine compounds, iodonium salts, and sulfonium salts. Good too. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (the above, BASF Japan Ltd. ), Seiqual BZ, Seiqual Z, Seiqual BEE (manufactured by Seiko Kagaku Co., Ltd.), Kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), Adeka Optomer SP- 152, ADEKA OPTOMER SP-170, ADEKA OPTOMER N-1717, ADEKA OPTOMER N-1919, ADEKA ARCLES NCI-831, ADEKA ARCLES NCI-930 (manufactured by ADEKA Co., Ltd.), TAZ-A, TAZ -PP (manufactured by Nippon Siberhegner Co., Ltd.) and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.).
The photopolymerization initiator contained in the polymerizable liquid crystal composition is at least one type, and multiple types may be used in combination, and if appropriately selected in relation to the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition good.

The photopolymerization initiator can fully utilize the energy emitted from the light source and has excellent productivity, so it is preferable that the maximum absorption wavelength is 300 nm to 400 nm, and more preferably 300 nm to 380 nm. Among them, α-acetophenone-based polymerization initiators and oxime-based photopolymerization initiators are preferred.

Examples of α-acetophenone compounds include 2-methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one, 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutan-1-one, and 2-dimethylamino-1-(4-morpholinophenyl)-2-(4-methylphenylmethyl)butan-1-one, and more preferably 2-methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one and 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutan-1-one. Commercially available α-acetophenone compounds include Irgacure 369, 379EG, and 907 (all manufactured by BASF Japan Ltd.) and Seikuol BEE (manufactured by Seiko Chemical Co., Ltd.).

The oxime ester photopolymerization initiator generates radicals such as phenyl radicals and methyl radicals when irradiated with light. The polymerization of the polymerizable liquid crystal compound progresses suitably with these radicals, and among them, oxime ester photopolymerization initiators that generate methyl radicals are preferred because of their high initiation efficiency of the polymerization reaction. Furthermore, from the viewpoint of allowing the polymerization reaction to proceed more efficiently, it is preferable to use a photopolymerization initiator that can efficiently utilize ultraviolet light having a wavelength of 350 nm or more. As a photopolymerization initiator that can efficiently utilize ultraviolet light with a wavelength of 350 nm or more, triazine compounds and carbazole compounds containing an oxime ester structure are preferred, and carbazole compounds containing an oxime ester structure are more preferred from the viewpoint of sensitivity. Examples of carbazole compounds containing an oxime ester structure include 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2- Examples include methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime). Commercially available oxime ester photopolymerization initiators include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (manufactured by BASF Japan Co., Ltd.), Adeka Optomer N-1919, and Adeka Arcles NCI-831. (All of the above are manufactured by ADEKA Co., Ltd.).

The content of the photopolymerization initiator is usually 0.1 to 30 parts by mass, preferably 1 to 20 parts by mass, and more preferably 1 to 15 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. Within the above range, the reaction of the polymerizable group proceeds sufficiently, and the orientation of the polymerizable liquid crystal compound is unlikely to be disturbed.

A leveling agent is an additive that adjusts the fluidity of a polymerizable liquid crystal composition and functions to make the coating film obtained by applying the composition flatter. Examples include silicone-based, polyacrylate-based, and perfluoroalkyl-based leveling agents. As the leveling agent, a commercially available product may be used. Specific examples thereof include DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all manufactured by Dow Corning Toray Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001 (all manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all manufactured by Momentive Performance Materials Co., Ltd.). Japan LLC), Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (all manufactured by Sumitomo 3M Limited), Megafac (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-477, F-479, F-482, F-483, F-556 (all manufactured by DIC Corporation), F-top (trade name) EF301, EF3 03, EF351, EF352 (all manufactured by Mitsubishi Materials Electronics Co., Ltd.), Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (all manufactured by AGC Seimi Chemical Co., Ltd.), trade names E1830, E5844 (manufactured by Daikin Fine Chemical Research Institute Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (all trade names manufactured by BM Chemie Co., Ltd.), etc. The leveling agents can be used alone or in combination of two or more kinds.

The content of the leveling agent is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal compound. It is preferable that the content of the leveling agent is within the above range because it is easy to orient the polymerizable liquid crystal compound and the resulting cured liquid crystal film tends to be smoother.

By blending an antioxidant, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. The antioxidant may be a primary antioxidant selected from phenolic antioxidants, amine antioxidants, quinone antioxidants, nitroso antioxidants, or phosphorus antioxidants and sulfur antioxidants. It may also be a secondary antioxidant selected from type antioxidants. In order to polymerize the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound, the content of the antioxidant is usually 0.01 to 10 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound. The amount is preferably 0.1 to 5 parts by weight, more preferably 0.1 to 3 parts by weight. Antioxidants can be used alone or in combination of two or more.

By using a photosensitizer, the sensitivity of the photopolymerization initiator can be increased. Examples of the photosensitizer include xanthone such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; and rubrene. The photosensitizers can be used alone or in combination of two or more. The content of the photosensitizer is usually 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal compound. 3 parts by mass.

The reactive additive preferably has a carbon-carbon unsaturated bond and an active hydrogen-reactive group in its molecule. The term "active hydrogen-reactive group" as used herein refers to a group that is reactive with groups having active hydrogen, such as carboxyl group (-COOH), hydroxyl group (-OH), and amino group (-NH ₂ ). Representative examples thereof include a glycidyl group, an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, a thioisocyanate group, and a maleic anhydride group. The number of carbon-carbon unsaturated bonds or active hydrogen-reactive groups each of the reactive additives has is usually 1 to 20, preferably 1 to 10.

In the reactive additive, it is preferable that at least two active hydrogen-reactive groups exist, and in this case, the plurality of active hydrogen-reactive groups may be the same or different.

The carbon-carbon unsaturated bond of the reactive additive may be a carbon-carbon double bond, a carbon-carbon triple bond, or a combination thereof, but is preferably a carbon-carbon double bond. In particular, the reactive additive preferably contains a carbon-carbon unsaturated bond as a vinyl group and/or a (meth)acrylic group. Furthermore, a reactive additive in which the active hydrogen reactive group is at least one selected from the group consisting of an epoxy group, a glycidyl group, and an isocyanate group is preferred, and a reactive additive having an acrylic group and an isocyanate group is more preferred.

Specific examples of reactive additives include compounds having a (meth)acrylic group and an epoxy group, such as methacryloxyglycidyl ether and acryloxyglycidyl ether; compounds having a (meth)acrylic group and an oxetane group, such as oxetane acrylate and oxetane methacrylate; compounds having a (meth)acrylic group and a lactone group, such as lactone acrylate and lactone methacrylate; compounds having a vinyl group and an oxazoline group, such as vinyl oxazoline and isopropenyl oxazoline; oligomers of compounds having a (meth)acrylic group and an isocyanate group, such as isocyanatomethyl acrylate, isocyanatomethyl methacrylate, 2-isocyanatoethyl acrylate, or 2-isocyanatoethyl methacrylate. Also included are compounds having a vinyl group or vinylene group and an acid anhydride, such as methacrylic anhydride, acrylic anhydride, maleic anhydride, or vinyl maleic anhydride. Among these, methacryloxyglycidyl ether, acryloxyglycidyl ether, isocyanatomethyl acrylate, isocyanatomethyl methacrylate, vinyloxazoline, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, or oligomers thereof are preferred, and isocyanatomethyl acrylate, 2-isocyanatoethyl acrylate, or oligomers thereof are particularly preferred.

As the reactive additive, commercially available products can be used as they are or after being purified if necessary. Examples of commercially available products include Laromer (registered trademark) LR-9000 (manufactured by BASF).

When the polymerizable liquid crystal composition contains a reactive additive, the content of the reactive additive is usually 0.01 to 10 parts by mass, preferably 0.1 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. ~7 parts by mass.

The polymerizable liquid crystal compositions for forming the horizontally aligned liquid crystal cured film and the vertically aligned liquid crystal cured film are each obtained by stirring a polymerizable liquid crystal compound and components such as a solvent and a polymerization initiator at a predetermined temperature. be able to.

The horizontal alignment liquid crystal cured film and the vertical alignment liquid crystal cured film are, for example,
A coating film of a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound is formed on a substrate or an alignment film described below, the coating film is dried, and the polymerizable liquid crystal composition is a step of orienting the polymerizable liquid crystal compound, and
It can be produced by a method including a step of polymerizing a polymerizable liquid crystal compound while maintaining an oriented state to form a cured liquid crystal film.

The coating film of the polymerizable liquid crystal composition can be formed by applying the polymerizable liquid crystal composition onto a substrate or an alignment film formed on the substrate as described below.
Examples of the base material include glass base materials and film base materials, but resin film base materials are preferred from the viewpoint of processability. Examples of the resin constituting the film base material include polyolefins such as polyethylene, polypropylene, and norbornene polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate ester; polyacrylate ester; triacetyl cellulose; Cellulose esters such as diacetyl cellulose and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyether sulfone; polyether ketone; plastics such as polyphenylene sulfide and polyphenylene oxide. Such a resin can be used as a base material by forming a film by known means such as a solvent casting method and a melt extrusion method. The surface of the base material may have a protective layer formed from acrylic resin, methacrylic resin, epoxy resin, oxetane resin, urethane resin, melamine resin, etc., and may be subjected to mold release treatment such as silicone treatment, corona treatment, Surface treatment such as plasma treatment may be performed.

Commercially available products may be used as the substrate. Examples of commercially available cellulose ester substrates include cellulose ester substrates manufactured by Fuji Photo Film Co., Ltd., such as Fujitac Film; cellulose ester substrates manufactured by Konica Minolta Opto Co., Ltd., such as "KC8UX2M", "KC8UY", and "KC4UY". Examples of commercially available cyclic olefin resins include cyclic olefin resins manufactured by Ticona (Germany), such as "Topas (registered trademark)", cyclic olefin resins manufactured by JSR Corporation, such as "Arton (registered trademark)", cyclic olefin resins manufactured by Zeon Corporation, such as "ZEONOR (registered trademark)" and "ZEONEX (registered trademark)", and cyclic olefin resins manufactured by Mitsui Chemicals, Inc., such as "Apel" (registered trademark). Commercially available cyclic olefin resin substrates may also be used. Commercially available cyclic olefin resin substrates include cyclic olefin resin substrates manufactured by Sekisui Chemical Co., Ltd., such as "S-Cina (registered trademark)" and "SCA40 (registered trademark)"; cyclic olefin resin substrates manufactured by Optes Co., Ltd., such as "ZEONORFILM (registered trademark)"; and cyclic olefin resin substrates manufactured by JSR Corporation, such as "ARTONFILM (registered trademark)."

It is preferable that the substrate is one that can be ultimately peeled off from the laminate of the present invention. From the viewpoints of ease of peeling off the substrate, ease of handling, thinning of the laminate, etc., the thickness of the substrate is usually 5 to 300 μm, and preferably 10 to 150 μm.

Methods for applying the polymerizable liquid crystal composition to a substrate or the like include known methods such as application methods such as spin coating, extrusion, gravure coating, die coating, bar coating, and applicator methods, and printing methods such as flexography.

Next, the solvent is removed by drying or the like to form a dried coating film. Examples of drying methods include natural drying, ventilation drying, heat drying, and reduced pressure drying. In this case, by heating the coating film obtained from the polymerizable liquid crystal composition, the solvent can be dried and removed from the coating film, and the polymerizable liquid crystal compound can be aligned in a desired direction (for example, horizontal or vertical) relative to the coating film plane. The heating temperature of the coating film can be appropriately determined in consideration of the materials of the polymerizable liquid crystal compound used and the substrate on which the coating film is formed, and the like, but in order to phase-transition the polymerizable liquid crystal compound to a liquid crystal phase state, it is usually necessary that the temperature is equal to or higher than the liquid crystal phase transition temperature. In order to make the polymerizable liquid crystal compound have a desired alignment state while removing the solvent contained in the polymerizable liquid crystal composition, for example, the composition can be heated to a temperature equal to or higher than the liquid crystal phase transition temperature (smectic phase transition temperature or nematic phase transition temperature) of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition. The heating temperature is preferably 3° C. or higher, more preferably 5° C. or higher than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound. The upper limit of the heating temperature is not particularly limited, but in order to avoid damage to the coating film, substrate, etc. due to heating, it is preferably 180° C. or less, more preferably 150° C. or less.
The liquid crystal phase transition temperature can be measured, for example, using a polarizing microscope equipped with a temperature control stage, a differential scanning calorimeter (DSC), a thermogravimetric differential thermal analyzer (TG-DTA), or the like. When two or more polymerizable liquid crystal compounds are used in combination, the phase transition temperature means a temperature measured in the same manner as when one type of polymerizable liquid crystal compound is used, using a mixture of polymerizable liquid crystal compounds in which all polymerizable liquid crystal compounds constituting the polymerizable liquid crystal composition are mixed in the same ratio as the composition in the polymerizable liquid crystal composition. It is generally known that the liquid crystal phase transition temperature of a polymerizable liquid crystal compound in a polymerizable liquid crystal composition may be lower than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound alone.

The heating time can be appropriately determined depending on the heating temperature, the type of polymerizable liquid crystal compound used, the type of solvent, its boiling point, its amount, etc., but is usually 0.5 to 10 minutes, preferably 0.5 minutes. ~5 minutes.

Removal of the solvent from the coating film may be performed simultaneously with heating the polymerizable liquid crystal compound to a temperature equal to or higher than the liquid crystal phase transition temperature, or may be performed separately, but it is preferably performed simultaneously from the viewpoint of improving productivity. Before heating the polymerizable liquid crystal compound to a temperature higher than the liquid crystal phase transition temperature, the solvent in the coating film obtained from the polymerizable liquid crystal composition is adjusted to an appropriate level under conditions such that the polymerizable liquid crystal compound contained in the coating film obtained from the polymerizable liquid crystal composition does not polymerize. A preliminary drying step for removal may be provided. Drying methods in this pre-drying step include natural drying, ventilation drying, heating drying, reduced pressure drying, etc. The drying temperature (heating temperature) in this drying step depends on the type of polymerizable liquid crystal compound used and the solvent. It can be determined as appropriate depending on the type, boiling point, amount, etc.

Next, in the obtained dry coating film, the polymerizable liquid crystal compound is polymerized by light irradiation while maintaining the orientation state of the polymerizable liquid crystal compound, thereby forming a polymer of the polymerizable liquid crystal compound existing in the desired orientation state. A certain liquid crystal cured film is formed. As the polymerization method, a photopolymerization method is usually used. In photopolymerization, the light irradiated to the dry coating film depends on the type of photopolymerization initiator contained in the dry coating film, the type of polymerizable liquid crystal compound (especially the type of polymerizable group possessed by the polymerizable liquid crystal compound) and the amount thereof is selected as appropriate. Specific examples include one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays, and active energy rays such as active electron beams. It will be done. Among these, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use photopolymerization equipment that is widely used in the field. It is preferable to select the type of polymerizable liquid crystal compound and photopolymerization initiator contained in the polymerizable liquid crystal composition. Moreover, during polymerization, the polymerization temperature can also be controlled by irradiating the dry coating film with light while cooling it with an appropriate cooling means. By employing such a cooling means and polymerizing the polymerizable liquid crystal compound at a lower temperature, a cured liquid crystal film can be appropriately formed even if a base material with relatively low heat resistance is used. It is also possible to promote the polymerization reaction by increasing the polymerization temperature within a range that does not cause problems due to heat during light irradiation (such as deformation of the base material due to heat). A patterned cured film can also be obtained by performing masking or development during photopolymerization.

Examples of light sources 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, LED light sources emitting light in the wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

The ultraviolet irradiation intensity is usually 10 to 3,000 mW/ ^cm2 . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating a photopolymerization initiator. The time for irradiating light is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, and even more preferably 0.1 seconds to 1 minute. When irradiating once or multiple times with such ultraviolet irradiation intensity, the integrated light amount is 10 to 3,000 mJ/ ^cm2 , preferably 50 to 2,000 mJ/ ^cm2 , and more preferably 100 to 1,000 mJ/ ^cm2 .

The thickness of the liquid crystal cured film can be appropriately selected depending on the type of liquid crystal cured film, the display device to which it is applied, etc. It is preferably 0.1 to 5 μm, more preferably 0.2 to 4 μm, and even more preferably 0.2 to 3 μm.

A horizontally aligned liquid crystal cured film and/or a vertically aligned liquid crystal cured film may be formed on the alignment film. The alignment film has an alignment regulating force that causes the polymerizable liquid crystal compound to align the liquid crystal in a desired direction. By forming a cured liquid crystal film using a horizontal alignment film having an alignment regulating force to align the polymerizable liquid crystal compound in the horizontal direction or a vertical alignment film having an alignment regulating force to align the polymerizable liquid crystal compound in the vertical direction, the polymerizable liquid crystal compound can be cured. can be oriented in a desired direction with higher precision, and a cured liquid crystal film that exhibits excellent optical properties when incorporated into a display device or the like can be obtained. The alignment regulating force can be adjusted arbitrarily depending on the type of alignment film, surface condition, rubbing conditions, etc., and if the alignment film is made of a photo-alignable polymer, it can be adjusted arbitrarily by changing the polarized light irradiation conditions, etc. It is possible to do so.

The alignment film is preferably one that has a solvent resistance that does not dissolve when the polymerizable liquid crystal composition is applied, etc., and also has heat resistance in heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound. Examples of the alignment film include an alignment film containing an alignment polymer, a photo-alignment film, a groove alignment film having a concavo-convex pattern or a plurality of grooves on the surface, and a stretched film stretched in the alignment direction. A photo-alignment film is preferred from the viewpoint of quality.

Examples of oriented polymers include polyamides and gelatins having amide bonds in the molecule, polyimides having imide bonds in the molecule, and their hydrolyzates such as polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid esters. Of these, polyvinyl alcohol is preferred. Oriented polymers can be used alone or in combination of two or more.

An alignment film containing an alignment polymer is usually produced by applying a composition in which an alignment polymer is dissolved in a solvent (hereinafter also referred to as an "alignment polymer composition") to a surface on which an alignment film is to be formed, such as a base film. , by removing the solvent, or by applying the oriented polymer composition to a base material, removing the solvent, and rubbing (rubbing method). Examples of the solvent include the same solvents as those exemplified above as solvents that can be used in the polymerizable liquid crystal composition.

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

As the oriented polymer composition, commercially available alignment film materials may be used as they are. Examples of commercially available alignment film materials include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optomer (registered trademark, manufactured by JSR Corporation).

Examples of the method for applying the oriented polymer composition to the surface on which the oriented film is to be formed, such as the base film, include the same methods as those exemplified as the method for applying the polymerizable liquid crystal composition to the base film.

Methods for removing the solvent contained in the oriented polymer composition include natural drying, ventilation drying, heat drying, and reduced pressure drying.

In order to impart an alignment regulating force to the alignment film, rubbing treatment can be performed as necessary (rubbing method). As a method of imparting an orientation regulating force by a rubbing method, a rubbing cloth is wrapped around a rotating rubbing roll, and an oriented polymer composition is applied to a substrate and annealed to form an oriented polymer composition on the surface of the substrate. Examples include a method of bringing oriented polymer films into contact with each other. If masking is performed when performing the rubbing process, a plurality of regions (patterns) with different orientation directions can be formed on the alignment film.

A photo-alignment film is usually prepared by adding a composition containing a polymer and/or monomer having a photo-reactive group and a solvent (hereinafter also referred to as a "composition for forming a photo-alignment film") to a substrate on which an alignment film is to be formed. It is obtained by coating the surface, removing the solvent, and then irradiating it with polarized light (preferably polarized UV). The photo-alignment film is also advantageous in that 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 when irradiated with light. Specific examples include groups involved in photoreactions that are the origin of liquid crystal alignment ability, such as molecular alignment induction caused by light irradiation, or isomerization reactions, dimerization reactions, photocrosslinking reactions, or photodecomposition reactions. Among these, groups involved in dimerization reactions or photocrosslinking reactions are preferred in terms of excellent alignment ability. As the photoreactive group, a group having an unsaturated bond, particularly a double bond, is preferred, and a group having at least one bond selected from the group consisting of a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N bond), and a carbon-oxygen double bond (C=O bond) is particularly preferred.

Examples of the photoreactive group having a C═C bond include a vinyl group, a polyene group, a stilbene group, a stilbazole group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C=N bond include groups having structures such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N=N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C═O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. 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, and a halogenated alkyl group.

Among these, photoreactive groups involved in photodimerization reactions are preferred, and cinnamoyl and chalcone groups are preferred as photoreactive groups because the amount of polarized light irradiation required for photoalignment is relatively small and it is easy to obtain a photoalignment film that is excellent in thermal stability and stability over time. In particular, when the liquid crystal cured film is formed from a polymerizable liquid crystal compound having a (meth)acryloyloxy group as the polymerizable group, the adhesion to the liquid crystal cured film can be improved by using a polymer having a photoreactive group that forms an alignment film and has a cinnamoyl group such that the terminal of the polymer side chain has a cinnamic acid structure.

Examples of the solvent contained in the composition for forming a photo-alignment film include those similar to those listed above as solvents that can be used in the polymerizable liquid crystal composition. It can be selected as appropriate.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be adjusted as appropriate depending on the type of polymer or monomer and the desired thickness of the photo-alignment film, but is preferably at least 0.2% by mass, more preferably in the range of 0.3 to 10% by mass, relative to the mass of the composition for forming a photo-alignment film. The composition for forming a photo-alignment film may contain a polymer material such as polyvinyl alcohol or polyimide, or a photosensitizer, as long as the properties of the photo-alignment film are not significantly impaired.

The method for applying the composition for forming a photo-alignment film on the surface on which the alignment film is to be formed includes the same method as the method for applying the alignment polymer composition. Examples of methods for removing the solvent from the applied composition for forming a photoalignment film include natural drying, ventilation drying, heat drying, and reduced pressure drying.

In order to irradiate polarized light, polarized UV can be irradiated directly onto the composition for forming a photo-alignment film coated on the substrate, from which the solvent has been removed, or the polarized light can be irradiated from the substrate side and the polarized light can be transmitted. It may also be a form of irradiation. Moreover, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength range in which a polymer having a photoreactive group or a photoreactive group of a monomer can absorb light energy. Specifically, UV (ultraviolet light) having a wavelength in the range of 250 to 400 nm is particularly preferred. Examples of light sources 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. preferable. Among these, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because they emit a high intensity of ultraviolet light with a wavelength of 313 nm. Polarized UV can be irradiated by passing the light from the light source through a suitable polarizer. As such a polarizer, a polarizing filter, a polarizing prism such as Glan-Thompson or Glan-Taylor, or a wire grid type polarizer can be used.

Note that by performing masking when performing rubbing or polarized light irradiation, it is also possible to form a plurality of regions (patterns) in which the directions of liquid crystal alignment are different.

A groove alignment film is a film that has a concave-convex pattern or multiple grooves on its surface. When a polymerizable liquid crystal compound is applied to a film that has multiple equally spaced linear grooves, the liquid crystal molecules are oriented in the direction along the grooves.

Methods for obtaining a groove alignment film include a method in which the surface of a photosensitive polyimide film is exposed through an exposure mask having slits in the shape of a pattern, followed by development and rinsing to form an uneven pattern; a method in which a layer of uncured UV-cured resin is formed on a plate-shaped master having grooves on its surface, and the formed resin layer is transferred to a substrate or the like and then cured; and a method in which a roll-shaped master having multiple grooves is pressed against an uncured UV-cured resin film formed on the surface on which the alignment film is to be formed to form unevenness, followed by curing.

The thickness of the alignment film (alignment film containing an alignment polymer or photoalignment film) is usually in the range of 10 to 10,000 nm, preferably in the range of 10 to 2,500 nm, more preferably 10 to 1,000 nm or less, even more preferably 10 to 500 nm, and particularly preferably 50 to 250 nm.

In the laminate of the present invention, the adhesive forming the adhesive layer located between the horizontally aligned liquid crystal cured film and the vertically aligned liquid crystal cured film is not particularly limited as long as it can form a layer having a refractive index that satisfies formula (1) in relation to the in-plane refractive index of the vertically aligned liquid crystal cured film, and for example, any adhesive known in the field of optical films can be used.

In the present invention, from the viewpoint of improving optical properties, it is preferable to control the retardation value of the vertically aligned liquid crystal cured film constituting the laminate to a specific range, for example, as shown in the above formula (5), and accordingly, the refractive index of the vertically aligned liquid crystal cured film is also in a specific range. Therefore, when controlling the difference between the in-plane refractive index of the adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film so as to satisfy formula (1), it is preferable to adjust the in-plane retardation value of the adhesive layer to approximate the in-plane refractive index of the vertically aligned liquid crystal cured film.

Examples of adhesives include chemically reactive adhesives, dry-solidifying adhesives, and pressure-sensitive adhesives. Examples of chemically reactive adhesives include active energy ray-curable adhesives. In one aspect of the present invention, it is preferable that the adhesive forming the adhesive layer is an active energy ray-curable adhesive.

An active energy ray curable adhesive is an adhesive that cures when irradiated with active energy rays. Active energy ray curable adhesives can be classified according to their curing mode into cationic polymerization adhesives containing a cationic polymerizable compound as a curable compound, radical polymerization adhesives containing a radical polymerizable compound as a curable compound, and hybrid curable adhesives containing both cationic polymerizable compounds and radical polymerizable compounds. Specific examples of cationic polymerizable compounds include epoxy compounds having one or more epoxy groups in the molecule, oxetane compounds having one or more oxetane rings in the molecule, and vinyl compounds. Specific examples of radical polymerizable compounds include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule, and vinyl compounds. An active energy ray curable adhesive can contain one or more cationic polymerizable compounds and/or one or more radical polymerizable compounds.

A cationically polymerizable compound, which is the main component of a cationically polymerizable adhesive, refers to a compound or oligomer that undergoes a cationic polymerization reaction and hardens upon irradiation or heating with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. , epoxy compounds, oxetane compounds, vinyl compounds, etc. Among these, preferred cationically polymerizable compounds are epoxy compounds.

An epoxy compound is a compound having one or more, preferably two or more, epoxy groups in the molecule. The epoxy compounds may be used alone or in combination of two or more. Examples of the epoxy compound include alicyclic epoxy compounds, aromatic epoxy compounds, hydrogenated epoxy compounds, and aliphatic epoxy compounds.

Alicyclic epoxy compounds are compounds that have one or more epoxy groups bonded to an alicyclic ring in the molecule. Specific examples include 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate, ethylene bis(3,4-epoxycyclohexanecarboxylate), bis(3,4-epoxycyclohexylmethyl) adipate, and bis(3,4-epoxy-6-methylcyclohexylmethyl) Adipate, diethylene glycol bis(3,4-epoxycyclohexyl methyl ether), ethylene glycol bis(3,4-epoxycyclohexyl methyl ether), 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispiro[5.2.2.5.2.2]henicosane, 3-(3,4-epoxycyclohexyl)-8,9-epoxy-1,5-dioxaspiro[5.5]undecane, 4-vinylcyclohexene dioxide, limonene dioxide, bis(2,3-epoxycyclopentyl)ether, and dicyclopentadiene dioxide.

Aromatic epoxy compounds are compounds that have an aromatic ring and an epoxy group in the molecule. Specific examples include bisphenol-type epoxy compounds such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl ether of bisphenol S, or oligomers thereof; phenol novolac epoxy resin, cresol novolac epoxy resin, hydroxybenzaldehyde phenol. Novolac-type epoxy resins such as novolak epoxy resin; polyfunctional type epoxy resins such as glycidyl ether of 2,2',4,4'-tetrahydroxydiphenylmethane, glycidyl ether of 2,2',4,4'-tetrahydroxybenzophenone, etc. Epoxy compounds; examples include polyfunctional epoxy resins such as epoxidized polyvinylphenol.

The hydrogenated epoxy compound is a glycidyl ether of a polyol having an alicyclic ring, and may be a glycidyl ether of a nuclear hydrogenated polyhydroxy compound obtained by selectively hydrogenating an aromatic polyol at an aromatic ring under pressure in the presence of a catalyst. Specific examples of aromatic polyols include bisphenol-type compounds such as bisphenol A, bisphenol F, and bisphenol S; novolac-type resins such as phenol novolac resin, cresol novolac resin, and hydroxybenzaldehyde phenol novolac resin; and polyfunctional compounds such as tetrahydroxydiphenylmethane, tetrahydroxybenzophenone, and polyvinylphenol. The glycidyl ether can be obtained by reacting epichlorohydrin with an alicyclic polyol obtained by hydrogenating the aromatic ring of an aromatic polyol.

Aliphatic epoxy compounds are compounds that have at least one oxirane ring (three-membered cyclic ether) bonded to an aliphatic carbon atom in the molecule. Examples include monofunctional epoxy compounds such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether; bifunctional epoxy compounds such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether; trifunctional or higher epoxy compounds such as trimethylolpropane triglycidyl ether and pentaerythritol tetraglycidyl ether; and epoxy compounds that have one epoxy group bonded directly to an alicyclic ring and an oxirane ring bonded to an aliphatic carbon atom, such as 4-vinylcyclohexene dioxide and limonene dioxide.

An oxetane compound, which is one of the cationically polymerizable compounds, is a compound containing one or more oxetane rings (oxetanyl group) in the molecule. Specifically, for example, 3-ethyl-3-hydroxymethyloxetane (also called oxetane alcohol), 2-ethylhexyloxetane, 1,4-bis[{(3-ethyloxetan-3-yl)methoxy}methyl] Benzene (also called xylylenebisoxetane), 3-ethyl-3[{(3-ethyloxetan-3-yl)methoxy}methyl]oxetane, 3-ethyl-3-(phenoxymethyl)oxetane, 3-(cyclohexyl) oxy)methyl-3-ethyloxetane. The oxetane compound may be used as the main component of the cationically polymerizable compound, or may be used in combination with an epoxy compound.

Examples of the vinyl compound that can be a cationic polymerizable compound include aliphatic or alicyclic vinyl ether compounds, and specific examples thereof include n-amyl vinyl ether, i-amyl vinyl ether, n-hexyl vinyl ether, and n-octyl vinyl ether. , 2-ethylhexyl vinyl ether, n-dodecyl vinyl ether, stearyl vinyl ether, vinyl ether of alkyl or alkenyl alcohol having 5 to 20 carbon atoms, such as oleyl vinyl ether; 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, etc. Hydroxyl group-containing vinyl ethers; vinyl ethers of monoalcohols with aliphatic or aromatic rings such as cyclohexyl vinyl ether, 2-methylcyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, benzyl vinyl ether; glycerol monovinyl ether, 1,4-butanediol monovinyl ether, 1, 4-Butanediol divinyl ether, 1,6-hexanediol divinyl ether, neopentyl glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol tetravinyl ether, trimethylolpropane divinyl ether, trimethylolpropane trivinyl ether, 1,4-dihydroxycyclohexane Mono- to polyvinyl ethers of polyhydric alcohols such as monovinyl ether, 1,4-dihydroxycyclohexane divinyl ether, 1,4-dihydroxymethylcyclohexane monovinyl ether, 1,4-dihydroxymethylcyclohexane divinyl ether; diethylene glycol divinyl ether, triethylene glycol divinyl ether; Polyalkylene glycol mono- to divinyl ethers such as vinyl ether and diethylene glycol monobutyl monovinyl ether; other vinyl ethers such as glycidyl vinyl ether and ethylene glycol vinyl ether methacrylate. The vinyl compound may be used as the main component of the cationically polymerizable compound, or may be used in combination with an epoxy compound or an epoxy compound and an oxetane compound.

By appropriately selecting the types and combinations of cationic polymerizable compounds as main components, their content, etc., the surface of the adhesive layer formed from the active energy ray-curable adhesive containing the cationic polymerizable compounds The internal refractive index can be controlled within a desired range.
For example, by including an aromatic epoxy compound or an alicyclic epoxy compound, the in-plane refractive index of the resulting pressure-sensitive adhesive layer tends to increase. For example, by containing an aliphatic epoxy compound, an oxetane compound, or a vinyl compound, the in-plane refractive index of the resulting pressure-sensitive adhesive layer tends to be lower. By including a compound that tends to increase the in-plane refractive index and a compound that tends to decrease the in-plane refractive index in an appropriate combination, the in-plane refractive index of the resulting adhesive layer can be adjusted to a desired value. It becomes easier to control the range.

The content of the cationic polymerizable compound in the cationic polymerizable adhesive (including the case where it is a hybrid type curable adhesive) is preferably based on 100% by mass of the total amount of the curable compound contained in the cationic polymerizable adhesive. is 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more. In addition, when the cationically polymerizable adhesive contains two or more types of cationically polymerizable compounds, it is preferable that the total amount thereof is within the above range.

When the active energy ray-curable adhesive contains a cationically polymerizable compound, it preferably contains a photocationic polymerization initiator. A photocationic polymerization initiator is one that generates cationic species or Lewis acids upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams, and initiates the polymerization reaction of cationic curable compounds. . Since a photocationic polymerization initiator acts catalytically with light, it has excellent storage stability and workability even when mixed with a photocationic polymerizable compound. Examples of compounds that generate cationic species or Lewis acids upon irradiation with active energy rays include onium salts such as aromatic iodonium salts and aromatic sulfonium salts, aromatic diazonium salts, iron-arene complexes, and the like.

An aromatic iodonium salt is a compound having a diaryliodonium cation, and the cation typically includes a diphenyliodonium cation. The aromatic sulfonium salt is a compound having a triarylsulfonium cation, and typical examples of the cation include triphenylsulfonium cation and 4,4'-bis(diphenylsulfonio)diphenylsulfide cation. An aromatic diazonium salt is a compound having a diazonium cation, and the cation typically includes a benzenediazonium cation. Further, the iron-arene complex is typically a cyclopentadienyl iron (II) arene cation complex salt.

The above-mentioned cations are paired with anions (negative ions) to form a photocationic polymerization initiator. Examples of anions that form a photocationic polymerization initiator include special phosphorus-based anions [(Rf) _n PF _6-n ] ^- , hexafluorophosphate anions PF ₆ ^- , hexafluoroantimonate anions SbF ₆ ^- , pentafluorohydroxyantimonate anions SbF ₅ (OH) ^- , hexafluoroarsenate anions AsF ₆ ^- , tetrafluoroborate anions BF ₄ ^- , and tetrakis (pentafluorophenyl) borate anions B (C ₆ F ₅ ) ₄ ^- . Among these, from the viewpoint of the curability of the cationic polymerizable compound and the safety of the resulting adhesive layer, special phosphorus-based anions [(Rf) _n PF _6-n ] ^- and hexafluorophosphate anions PF ₆ ^- are preferred.

The photocationic polymerization initiators may be used alone or in combination of two or more. Among these, aromatic sulfonium salts are preferably used because they have ultraviolet absorption characteristics even in the wavelength region of around 300 nm, have excellent curability, and can provide cured products having good mechanical strength and adhesive strength.

The amount (solid content) of the photocationic polymerization initiator in the cationic polymerization adhesive is usually 0.5 to 10 parts by mass, and preferably 6 parts by mass or less, per 100 parts by mass of the cationic polymerizable compound. When the content of the photocationic polymerization initiator is within the above range, the cationic polymerizable compound can be sufficiently cured.

A hybrid type adhesive can also be obtained by incorporating a radically polymerizable compound in addition to the cationically polymerizable compound into the cationically polymerizable adhesive. By using a radically polymerizable compound in combination, the in-plane refractive index of the pressure-sensitive adhesive layer may be easily adjusted.

Radical polymerizable compounds, which are the main components of radical polymerizable adhesives, refer to compounds or oligomers that undergo a radical polymerization reaction and harden when irradiated with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays or by heating. Specifically, compounds having an ethylenically unsaturated bond can be mentioned. Compounds with ethylenically unsaturated bonds include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule, as well as styrene, styrene sulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl. Examples include vinyl compounds such as -2-pyrrolidone. These may be used alone or in combination of two or more.

Examples of (meth)acrylic compounds include (meth)acrylate monomers having at least one (meth)acryloyloxy group in the molecule, (meth)acrylamide monomers, and (meth)acryloyl group-containing compounds such as (meth)acrylic oligomers obtained by reacting two or more functional group-containing compounds and having at least two (meth)acryloyl groups in the molecule. The (meth)acrylic oligomer is preferably a (meth)acrylate oligomer having at least two (meth)acryloyloxy groups in the molecule.

When the active energy ray curable adhesive contains a radical polymerizable compound, it is preferable that it contains a photoradical polymerization initiator. The photoradical polymerization initiator initiates the polymerization reaction of the radical curable compound by irradiation with active energy rays such as visible light, ultraviolet light, X-rays, or electron beams. The photoradical polymerization initiator may be used alone or in combination of two or more types.

Specific examples of photoradical polymerization initiators include acetophenone, 3-methylacetophenone, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[ Acetophenone initiators such as 4-(methylthio)phenyl-2-morpholinopropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone, 4,4' - Benzophenone initiators such as diaminobenzophenone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; others include xanthone, fluorenone, camphorquinone, benzaldehyde, and anthraquinone .

The amount of the photoradical polymerization initiator in the radical polymerizable adhesive is usually 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the radical polymerizable compound. When the content of the photoradical polymerization initiator is within the above range, the radically polymerizable compound can be sufficiently cured.

The active energy ray-curable adhesive may contain additives such as cationic polymerization accelerators such as oxetane and polyol, photosensitizers, ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow control agents, plasticizers, defoamers, antistatic agents, leveling agents, and/or solvents, as necessary.

When an active energy ray curable adhesive is used, the adhesive layer is obtained by curing the active energy ray curable adhesive by irradiating it with active energy rays. The light source of the active energy rays is not particularly limited, but active energy rays having an emission distribution of wavelengths of 400 nm or less are preferred, and ultraviolet light is more preferred. Specific examples of light sources include low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra-high pressure mercury lamps, chemical lamps, black light lamps, microwave excited mercury lamps, and metal halide lamps.

The intensity of light irradiation to the active energy ray curable adhesive is appropriately determined depending on the composition of the active energy ray curable adhesive, and is not particularly limited, but the irradiation intensity in the wavelength range effective for activating the polymerization initiator is usually , 10 to 3,000 mW/cm ² . The light irradiation time to the active energy ray curable adhesive may be appropriately selected depending on the active energy ray curable adhesive to be cured, and is not particularly limited, but is usually 0.1 seconds to 10 minutes. The time is preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and even more preferably 10 seconds to 1 minute. When irradiated once or multiple times with such ultraviolet irradiation intensity, the cumulative amount of light is usually 10 to 3,000 mJ/cm ² , preferably 50 to 2,000 mJ/cm ² , more preferably 100 to 1,000 mJ/cm 2 ^cm2 .

The dry-setting adhesive contains as a main component a polymer of a monomer having a protic functional group such as a hydroxyl group, a carboxyl group, or an amino group and an ethylenically unsaturated group, or a urethane resin, and further contains a polyvalent adhesive. Examples include compositions containing crosslinking agents or curable compounds such as aldehydes, epoxy compounds, epoxy resins, melamine compounds, zirconia compounds, and zinc compounds. Examples of polymers of monomers having a protic functional group such as a hydroxyl group, a carboxyl group, or an amino group and an ethylenically unsaturated group include ethylene-maleic acid copolymers, itaconic acid copolymers, acrylic acid copolymers, and acrylamide. Examples include copolymers, saponified polyvinyl acetate, and polyvinyl alcohol resins.

Examples of polyvinyl alcohol resins include polyvinyl alcohol, partially saponified polyvinyl alcohol, completely saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. Can be mentioned. The content of polyvinyl alcohol resin in the water-based dry-setting adhesive is usually 1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of water.

Examples of the urethane resin include polyester-based ionomer type urethane resins. The polyester-based ionomer type urethane resin referred to herein is a urethane resin having a polyester skeleton into which a small amount of an ionic component (hydrophilic component) is introduced. Such an ionomer-type urethane resin emulsifies in water to form an emulsion without using an emulsifier, and therefore can be used as a water-based adhesive. When using a polyester ionomer type urethane resin, it is effective to blend a water-soluble epoxy compound as a crosslinking agent.

Examples of the epoxy resin include polyamide epoxy resins obtained by reacting epichlorohydrin with polyamide polyamines obtained by reacting polyalkylene polyamines such as diethylene triamine or triethylene tetramine with dicarboxylic acids such as adipic acid. Commercially available polyamide epoxy resins include "SUMIREZ RESIN (registered trademark) 650" and "SUMILEZE RESIN 675" (manufactured by Sumika Chemtex Co., Ltd.), and "WS-525" (manufactured by Nippon PMC Corporation). etc. When blending an epoxy resin, the amount added is usually 1 to 100 parts by weight, preferably 1 to 50 parts by weight, per 100 parts by weight of the polyvinyl alcohol resin.

The dry-setting adhesive may contain a solvent. Examples of the solvent include water, a mixed solvent of water and a hydrophilic organic solvent (for example, an alcohol solvent, an ether solvent, an ester solvent, etc.), an organic solvent, and the like. Examples of adhesive components include adhesives containing polyvinyl alcohol resin or urethane resin.

When a dry-solidifying adhesive is used, the coating of the dry-solidifying adhesive can be dried and cured to obtain a pressure-sensitive adhesive layer. This drying process can be carried out, for example, by blowing hot air onto the adhesive. The temperature depends on the type of solvent, but is usually in the range of 30 to 200°C, preferably 35 to 150°C, more preferably 40 to 100°C, and even more preferably 60 to 100°C. The drying time is usually about 10 seconds to 30 minutes.

Pressure-sensitive adhesives typically contain a polymer and may also contain a solvent. Examples of the polymer include acrylic polymers, silicone polymers, polyesters, polyurethanes, and polyethers. Among these, acrylic pressure-sensitive adhesives containing acrylic polymers are preferred because they have excellent optical transparency and can easily improve adhesiveness, heat resistance, and the like.

As the acrylic polymer, a copolymer of a (meth)acrylate in which the alkyl group of the ester portion is an alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, or a butyl group, and a (meth)acrylic monomer having a functional group, such as (meth)acrylic acid or hydroxyethyl (meth)acrylate, is preferred. The glass transition temperature of the acrylic polymer is preferably 25°C or lower, more preferably 0°C or lower. The mass average molecular weight of such an acrylic polymer is preferably 100,000 or higher.

Examples of the solvent include those listed as solvents that can be used in polymerizable liquid crystal compositions and the like. The pressure-sensitive adhesive may contain a light diffusing agent. The light diffusing agent is an additive that imparts light diffusibility to the adhesive, and may be fine particles having a refractive index different from that of the polymer contained in the adhesive. Examples of the light diffusing agent include fine particles made of inorganic compounds and fine particles made of organic compounds (polymers). Many of the polymers contained as active ingredients in adhesives, including acrylic polymers, have a refractive index of about 1.4 to 1.6, so it is preferable to appropriately select a light diffusing agent from those having a refractive index of 1.2 to 1.8. The difference in refractive index between the polymer contained as an active ingredient in the adhesive and the light diffusing agent is usually 0.01 or more, and from the viewpoint of the brightness and display properties of the display device, it is preferable that it is 0.01 to 0.2. The fine particles used as the light diffusing agent are preferably spherical fine particles, and more preferably fine particles close to monodispersion, and more preferably fine particles with an average particle size of 2 to 6 μm. The refractive index is measured by a general minimum deviation method or an Abbe refractometer.

Examples of inorganic compound particles include aluminum oxide (refractive index 1.76) and silicon oxide (refractive index 1.45). Examples of organic compound (polymer) particles include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate/styrene copolymer resin beads (refractive index 1.50-1.59), polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), and silicone resin beads (refractive index 1.46). The content of the light diffusing agent is usually 3-30 parts by mass per 100 parts by mass of polymer.

The thickness of the adhesive layer can be appropriately determined depending on the type of adhesive constituting the adhesive layer, the desired adhesive strength, etc., and is usually 0.01 μm or more and 20 μm or less, preferably 0.05 μm or more, more preferably 0.1 μm or more, particularly preferably 0.2 μm or more, and is preferably 20 μm or less, more preferably 10 μm or less, even more preferably 5 μm or less, particularly preferably 2 μm or less, and particularly preferably 1.5 μm or less.
In general, the thinner the thickness of the adhesive layer located between the horizontally aligned liquid crystal cured film and the vertically aligned liquid crystal cured film, the more likely the interfacial reflection occurring at the interface between the horizontally aligned liquid crystal cured film and the adhesive layer and the interfacial reflection occurring at the interface between the vertically aligned liquid crystal cured film and the adhesive layer will interfere with each other, and interference unevenness tends to occur. Even in such a case, the laminate of the present invention is advantageous because it can effectively suppress the occurrence of interference unevenness even if the thickness of the adhesive layer is thin, since the difference between the in-plane refractive index of the vertically aligned liquid crystal cured film and the in-plane refractive index of the adhesive layer is small and the occurrence of reflection at the interface between the vertically aligned liquid crystal cured film and the adhesive layer is suppressed. Therefore, in a preferred embodiment of the present invention, the thickness of the adhesive layer is preferably 0.1 μm or more and 2 μm or less, more preferably 0.2 μm or more and 1.5 μm or less. When the thickness of the adhesive layer is within the above range, interference unevenness is unlikely to occur, and the laminate can be made thinner while maintaining high adhesiveness.

The laminate of the present invention can be produced, for example, by laminating (bonding) a horizontally oriented liquid crystal cured film and a vertically oriented liquid crystal cured film via the pressure-sensitive adhesive layer.

The present invention includes an elliptical polarizing plate comprising the laminate of the present invention and a polarizing film.
The polarizing film is a film having a polarizing function, and examples of the polarizing film include a stretched film having a dye having absorption anisotropy adsorbed thereon, a film coated with a dye having absorption anisotropy, and the like, which includes a polarizer, etc. Examples of the dye having absorption anisotropy include a dichroic dye.

A film containing a stretched film adsorbed with a dye having absorption anisotropy as a polarizer is usually produced by uniaxially stretching a polyvinyl alcohol resin film, dyeing the polyvinyl alcohol resin film with a dichroic dye to adsorb the dichroic dye, treating the polyvinyl alcohol resin film with the adsorbed dichroic dye with an aqueous boric acid solution, and washing with water after the treatment with the aqueous boric acid solution, and then sandwiching at least one side of the polarizer produced by this process between a transparent protective film via an adhesive.

Polyvinyl alcohol resins are obtained by saponifying polyvinyl acetate resins. Polyvinyl acetate resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of vinyl acetate and other monomers that can be copolymerized with it. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides with ammonium groups.

The degree of saponification of polyvinyl alcohol resins is usually about 85 to 100 mol%, and preferably 98 mol% or more. Polyvinyl alcohol resins may be modified; for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The degree of polymerization of polyvinyl alcohol resins is usually about 1,000 to 10,000, and preferably in the range of 1,500 to 5,000.

A film made from such polyvinyl alcohol-based resin is used as the base film for the polarizing film. The method for making the polyvinyl alcohol-based resin into a film is not particularly limited, and the film can be made by a known method. The thickness of the polyvinyl alcohol-based base film can be, for example, about 10 to 150 μm.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing with a dichroic dye. When the uniaxial stretching is performed after dyeing, it may be performed before or during the boric acid treatment. It is also possible to perform the uniaxial stretching at these multiple stages. The uniaxial stretching may be performed uniaxially between rolls with different peripheral speeds, or may be performed uniaxially using a heated roll. The uniaxial stretching may be dry stretching in which the stretching is performed in the air, or wet stretching in which the polyvinyl alcohol-based resin film is stretched in a swollen state using a solvent. The stretching ratio is usually about 3 to 8 times.

Dyeing of a polyvinyl alcohol-based resin film with a dichroic dye is carried out, for example, by immersing the polyvinyl alcohol-based resin film in an aqueous solution containing the dichroic dye.

Specific examples of the dichroic pigment include iodine and dichroic organic dyes. Examples of the dichroic organic dye include dichroic direct dyes made of disazo compounds such as C.I. DIRECT RED 39, and dichroic direct dyes made of compounds such as trisazo and tetrakisazo. It is preferable to immerse the polyvinyl alcohol resin film in water before the dyeing process.

When using iodine as a dichroic dye, a method is usually employed in which a polyvinyl alcohol resin film is immersed in an aqueous solution containing iodine and potassium iodide for dyeing. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by mass per 100 parts by mass of water. Further, the content of potassium iodide is usually about 0.5 to 20 parts by mass per 100 parts by mass of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40°C. The immersion time (staining time) in this aqueous solution is usually about 20 to 1,800 seconds.

On the other hand, when a dichroic organic dye is used as the dichroic pigment, a method of dyeing a polyvinyl alcohol-based resin film by immersing it in an aqueous solution containing a water-soluble dichroic dye is usually adopted. The content of the dichroic organic dye in this aqueous solution is usually about 1×10 ⁻⁴ to 10 parts by mass, preferably 1×10 ⁻³ to 1 part by mass, and more preferably 1×10 ⁻³ to 1×10 ⁻² parts by mass per 100 parts by mass of water. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the dichroic dye aqueous solution used for dyeing is usually about 20 to 80° C. In addition, the immersion time in this aqueous solution (dyeing time) is usually about 10 to 1,800 seconds.

The boric acid treatment after dyeing with a dichroic dye can usually be carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous boric acid solution. The content of boric acid in this boric acid aqueous solution is usually about 2 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. When iodine is used as the dichroic dye, the boric acid aqueous solution preferably contains potassium iodide, and the content of potassium iodide in this case is usually 0.1 to 100 parts by mass of water. The amount is about 15 parts by mass, preferably 5 to 12 parts by mass. The immersion time in the boric acid aqueous solution is usually about 60 to 1,200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the boric acid treatment is usually 50°C or higher, preferably 50 to 85°C, more preferably 60 to 80°C.

The polyvinyl alcohol resin film treated with boric acid is usually washed with water. The water washing treatment can be performed, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of water in the washing process is usually about 5 to 40°C. The immersion time is usually about 1 to 120 seconds.

After washing with water, a drying process is performed to obtain a polarizer. The drying process can be performed using, for example, a hot air dryer or a far-infrared heater. The temperature of the drying process is usually about 30 to 100°C, and preferably 50 to 80°C. The time of the drying process is usually about 60 to 600 seconds, and preferably 120 to 600 seconds. The moisture content of the polarizer is reduced to a practical level by the drying process. The moisture content is usually about 5 to 20 mass%, and preferably 8 to 15 mass%. If the moisture content is within the above range, a polarizer having appropriate flexibility and excellent thermal stability can be obtained.

The thickness of the polarizer obtained by subjecting the polyvinyl alcohol resin film to uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, washing with water, and drying is preferably 5 to 40 μm.

Examples of films coated with a dye having absorption anisotropy include films obtained by coating a composition containing a dichroic dye having liquid crystal properties, or a composition containing a dichroic dye and a polymerizable liquid crystal. The film preferably has a protective film on one or both sides. Examples of the protective film include the same resin films as those exemplified above as substrates that can be used in the manufacture of horizontally aligned liquid crystal cured films.

It is preferable for a film coated with a dye having absorption anisotropy to be thin, but if it is too thin, the strength tends to decrease and processability tends to be poor. The thickness of the film is usually 20 μm or less, preferably 5 μm or less, and more preferably 0.5 to 3 μm.

Specific examples of films coated with a dye having the above-mentioned absorption anisotropy include the films described in JP-A-2012-33249, etc.

A polarizing film is obtained by laminating a transparent protective film on at least one surface of the thus obtained polarizer via an adhesive. As the transparent protective film, a transparent film similar to the resin film exemplified above as a base material that can be used for manufacturing a horizontally aligned liquid crystal cured film or the like can be preferably used.

The elliptically polarizing plate of the present invention includes the laminate of the present invention and a polarizing film, and for example, the laminate of the present invention and the polarizing film are laminated via an adhesive layer or the like. In this way, the elliptically polarizing plate of the present invention can be obtained. As the adhesive layer, any adhesive that is conventionally known in the field can be used, for example, an adhesive that can be used to laminate a horizontally aligned liquid crystal cured film and a vertically aligned liquid crystal cured film. Examples include adhesives similar to those exemplified above.

In one aspect of the present invention, when the laminate of the present invention and a polarizing film are laminated, it is preferable to laminate them so that the angle between the slow axis (optical axis) of the horizontally aligned liquid crystal cured film constituting the laminate and the absorption axis of the polarizing film is 45±5°.

The elliptically polarizing plate of the present invention may have a structure similar to that of a conventional general elliptically polarizing plate, or a polarizing film and a retardation film. Such structures include, for example, adhesive layers (sheets) used to bond elliptically polarizing plates to display elements such as organic EL, and adhesive layers used to protect the surfaces of polarizing films and retardation films from scratches and dirt. Protective films and the like can be mentioned.

The elliptically polarizing plate of the present invention can be used in various display devices.
A display device is a device having a display element, and includes a light-emitting element or a light-emitting device as a light source. Examples of the display device include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (e.g., a field emission display device (FED) and a surface field emission display device (SED)), electronic paper (a display device using electronic ink or an electrophoretic element, a plasma display device, a projection type display device (e.g., a grating light valve (GLV) display device, a display device having a digital micromirror device (DMD)), and a piezoelectric ceramic display. The liquid crystal display device includes any of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, and a projection type liquid crystal display device. These display devices may be display devices that display two-dimensional images, or stereoscopic display devices that display three-dimensional images. In particular, the elliptical polarizing plate of the present invention can be suitably used in an organic electroluminescence (EL) display device and an inorganic electroluminescence (EL) display device, and the laminate of the present invention can be suitably used in a liquid crystal display device and a touch panel display device. These display devices can exhibit good image display characteristics by being provided with the laminate of the present invention, which is unlikely to cause interference unevenness.

Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, "%" and "parts" in the examples mean % by mass and parts by mass, respectively, unless otherwise specified.

1. Preparation of adhesives (1) Preparation of active energy ray curable adhesives Cationic polymerizable compounds (monomers (A-1) to (A-6)) and cationic polymerization initiators were mixed and degassed according to the compositions shown in Table 1 (the units in Table 1 are parts by mass), and active energy ray curable adhesives A to F were prepared. The cationic polymerizable compounds, monomers (A-1) to (A-6), were each the components shown below, and the cationic polymerization initiator (B) was blended as a 50 mass% propylene carbonate solution, and the solid content thereof is shown in Table 1.

<Cationic polymerizable compound (monomer)>
A-1: 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (product name: CEL2021P, manufactured by Daicel Corporation)
A-2: 1,6-hexanediol diglycidyl ether (trade name: EX-212L, manufactured by Nagase ChemteX Co., Ltd.)
A-3: 4-Hydroxybutyl vinyl ether (trade name: HBVE, manufactured by Maruzen Petrochemical Co., Ltd.)
A-4: p-tert-butylphenyl glycidyl ether (trade name: EX-146, manufactured by Nagase ChemteX Co., Ltd.)
A-5: Bisphenol F type epoxy resin (product name: EXA-830CRP, manufactured by DIC Corporation)
A-6: 2-ethylhexyl glycidyl ether (product name: EX-121, manufactured by Nagase ChemteX Co., Ltd.)

<Cationic Polymerization Initiator>
B: Cationic polymerization initiator (product name: CPI-100P, manufactured by San-Apro Co., Ltd., 50% by weight solution)

(2) Method for measuring refractive index Each of the adhesives A to F prepared above was applied to one side of a cycloolefin polymer film (COP: ZF-14, manufactured by Zeon Corporation) using a bar coater [manufactured by Daiichi Rika Co., Ltd.], and a cured product was obtained by irradiating the film with ultraviolet light at an integrated light quantity of 600 mJ/cm ² (UV-B) using an ultraviolet irradiation device [manufactured by Fusion UV Systems Co., Ltd.]. The film thickness of the obtained cured product was measured from the difference in thickness with the cycloolefin polymer film using a contact film thickness meter, and was about 30 μm. The COP was peeled off from the obtained cured product, and the refractive index n2 (589 nm) of the cured product was measured using a multi-wavelength Abbe refractometer ["DR-M4" manufactured by Atago Co., Ltd.] in a 25° C. environment. The results are shown in Table 1.

2. Preparation of a composition for forming a vertically aligned liquid crystal cured film (1) Preparation of a composition 1 for forming a vertically aligned liquid crystal cured film The components were mixed according to the composition shown in Table 2, and the resulting solution was stirred at 80° C. for 1 hour, and then cooled to room temperature to prepare a composition 1 for forming a vertically aligned liquid crystal cured film.
In addition, each component in Table 2 is the component shown below, and the blending amount indicates the blending ratio of each component to the total amount of the prepared composition.

（２）水平配向液晶硬化膜形成用組成物１および垂直配向液晶硬化膜形成用組成物２の調製
以下に示す重合性液晶化合物Ａ、および重合性液晶化合物Ｂを９０：１０の質量比で混合した混合物に対して、レベリング剤（Ｆ－５５６；ＤＩＣ社製）を１質量部、および重合開始剤である２－ジメチルアミノ－２－ベンジル－１－（４－モルホリノフェニル）ブタン－１－オン（「イルガキュア３６９（Ｉｒｇ３６９）」、ＢＡＳＦジャパン株式会社製）を６質量部添加した。 Irg907: Cationic polymerization initiator [Irgacure 907 (manufactured by BASF Japan)]
BYK-361N: Leveling agent (manufactured by BYK Chemie Japan)
LR-9000: Reactive additive [Laromer (registered trademark) LR-9000 (manufactured by BASF Japan)]
PGMEA: Solvent (propylene glycol 1-monomethyl ether 2-acetate)
LC242: Polymerizable liquid crystal compound [Polymerizable liquid crystal compound represented by the following formula (manufactured by BASF)]

(2) Preparation of composition 1 for forming a horizontally aligned liquid crystal cured film and composition 2 for forming a vertically aligned liquid crystal cured film The following polymerizable liquid crystal compound A and polymerizable liquid crystal compound B are mixed at a mass ratio of 90:10. To the resulting mixture, 1 part by mass of a leveling agent (F-556; manufactured by DIC) and 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one as a polymerization initiator were added. ("Irgacure 369 (Irg369)", manufactured by BASF Japan Co., Ltd.) was added in an amount of 6 parts by mass.

Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration became 13%, and the mixture was stirred at 80°C for 1 hour to obtain composition 1 for forming a horizontally aligned liquid crystal cured film and composition 2 for forming a vertically aligned liquid crystal cured film.

Polymerizable liquid crystal compound A was produced according to the method described in JP-A No. 2010-31223. Furthermore, polymerizable liquid crystal compound B was produced according to the method described in JP-A No. 2009-173893. The molecular structure of each is shown below.

Polymerizable liquid crystal compound A

Polymerizable liquid crystal compound B

3. Preparation of composition for forming alignment film (1) Preparation of composition 1 for forming vertical alignment film 1 part by mass (solid content equivalent) of Sunever SE-610 (manufactured by Nissan Chemical Industries, Ltd.), which is a commercially available alignment polymer, contains 2 -99 parts by mass of butoxyethanol were added and mixed to obtain a composition for forming a vertical alignment film. The solid content of SE-610 was calculated from the concentration stated in the delivery specifications.

(2) Preparation of composition 2 for forming vertical alignment film A silane coupling agent "KBE-9103" manufactured by Shin-Etsu Chemical Co., Ltd. was dissolved in a mixed solvent of ethanol and water in a ratio of 9:1 (mass ratio) to obtain a composition for forming a vertical alignment film having a solid content of 0.5%.

(3) Preparation of a composition for forming a horizontal alignment film 5 parts by mass of a photoalignment material having the following structure (weight average molecular weight: 30,000) and 95 parts by mass of cyclopentanone (solvent) were mixed as components, and the resulting mixture was stirred at 80° C. for 1 hour to obtain a composition for forming a horizontal alignment film.

4. Production of polarizing film A polyvinyl alcohol film with a thickness of 30 μm (average degree of polymerization of about 2400, degree of saponification of 99.9 mol% or more) was uniaxially stretched to about 5 times by dry stretching, and further stretched to 40 mm while maintaining the tension state. It was immersed in pure water at ℃ for 40 seconds. Thereafter, it was immersed in a dyeing aqueous solution having a mass ratio of iodine/potassium iodide/water of 0.044/5.7/100 at 28° C. for 30 seconds to perform a dyeing treatment. Next, it was immersed in a boric acid aqueous solution having a mass ratio of potassium iodide/boric acid/water of 11.0/6.2/100 at 70° C. for 120 seconds. Subsequently, after washing with pure water at 8°C for 15 seconds, the polyvinyl alcohol film was dried at 60°C for 50 seconds and then at 75°C for 20 seconds while being held under a tension of 300N, so that iodine was adsorbed and oriented in the polyvinyl alcohol film. A polarizer with a thickness of 12 μm was obtained.
For the obtained polarizer, a saponified triacetyl cellulose film (TAC; KC2UA; manufactured by Konica Minolta, Inc., thickness: 25 μm) was applied to one side as a front transparent protective layer, and a film obtained by saponification treatment was applied to the other side. A cycloolefin polymer film (COP: ZF-14 manufactured by Nippon Zeon Co., Ltd.) that has been corona-treated and has a retardation value of approximately 0 at a wavelength of 550 nm is prepared in such a way that the thickness of the adhesive layer obtained between them is 50 nm. Adhesive was injected and the pieces were pasted together using nip rolls. While maintaining the tension of the obtained bond at 430 N/m, it was dried at 60° C. for 2 minutes to obtain a polarizing film having TAC as a transparent protective film on one side and COP on the other side. The water-based adhesive contains 100 parts by mass of water, 3 parts by mass of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318, manufactured by Kuraray), and a water-soluble polyamide epoxy resin (Sumirezu Resin 650, manufactured by Sumika Chemtex, with a solid content concentration of 30%). Aqueous solution] was prepared by adding 1.5 parts by mass.

5. Production of a laminate consisting of a base material, a horizontal alignment film, and a horizontally aligned liquid crystal cured film (1) Production of a laminate 1 consisting of a base material, a horizontal alignment film, and a horizontally aligned liquid crystal cured film COP film (ZF) manufactured by Nippon Zeon Co., Ltd. -14) After performing corona treatment on the surface, the composition for forming a horizontal alignment film prepared above was applied with a bar coater to the corona-treated surface and dried at 80° C. for 1 minute. Next, using a polarized UV irradiation device ("SPOT CURE SP-9", manufactured by Ushio Inc.), polarized UV exposure was performed at an axis angle of 45° with an integrated light amount of 100 mJ/ ^cm2 at a wavelength of 313 nm, and the image was exposed horizontally. An alignment film was obtained. The thickness of the obtained horizontal alignment film was measured with an ellipsometer and was found to be 100 nm.

Next, a composition 1 for forming a horizontally aligned liquid crystal cured film was applied to the horizontal alignment film using a bar coater, and dried at 120°C for 1 minute. After that, ultraviolet light was irradiated (under a nitrogen atmosphere, accumulated light amount at a wavelength of 365 nm: 500 mJ/cm ² ) using a high-pressure mercury lamp ("Unicur VB-15201BY-A", manufactured by Ushio Inc.) to form a horizontally aligned liquid crystal cured film 1, thereby obtaining a laminate 1 consisting of the substrate, the horizontal alignment film, and the horizontally aligned liquid crystal cured film 1. The thickness of the horizontally aligned liquid crystal cured film 1 in the obtained laminate 1 was measured with an ellipsometer and was found to be 2.3 μm.

(2) Measurement of retardation and three-dimensional refractive index of horizontally aligned liquid crystal cured film 1 was laminated to glass, and after peeling off the COP as a base material, measurement was performed using a measuring device ("KOBRA-WPR", manufactured by Oji Scientific Instruments Co., Ltd.). The measurement results of the phase difference value Re(λ) at each wavelength are Re(450)=121nm, Re(550)=142nm, Re(650)=146nm, Re(450)/Re(550)=0.85. there were. The three-dimensional refractive index at 589 nm was determined from the average refractive index and retardation value of the horizontally aligned liquid crystal cured film 1 obtained using an ellipsometer. The results are shown in Table 3.

6. Manufacture of a laminate consisting of a substrate, a vertical alignment film, and a vertical alignment liquid crystal cured film (1) Manufacture of a laminate 2 consisting of a substrate, a vertical alignment film, and a vertical alignment liquid crystal cured film 1 After performing a corona treatment on a COP film (ZF-14) manufactured by Zeon Corporation, a composition for forming a vertical alignment film 1 was applied to the corona-treated surface using a bar coater and dried at 90°C for 1 minute to form a vertical alignment film. The thickness of the obtained vertical alignment film was measured with an ellipsometer to be 70 nm. In addition, the retardation value of the obtained vertical alignment film at a wavelength of 550 nm was measured (measuring instrument: Oji Scientific Instruments, KOBRA-WR), and R ₀ (550) = 0.7 nm. Note that the retardation value of the COP at a wavelength of 550 nm is approximately 0, so there is no effect on the retardation value. Next, a composition 1 for forming a vertically aligned liquid crystal cured film was applied onto the obtained vertical alignment film using a bar coater, dried at 90°C for 1 minute, and irradiated with ultraviolet light (under a nitrogen atmosphere, integrated light amount at a wavelength of 365 nm: 1000 mJ/cm ² ) using a high-pressure mercury lamp (manufactured by Ushio Inc., Uniqure VB-15201BY-A) to form a vertically aligned liquid crystal cured film 1, thereby obtaining a laminate 2 consisting of a substrate, a vertical alignment film, and the vertically aligned liquid crystal cured film 1. The thickness of the vertically aligned liquid crystal cured film 1 in the obtained laminate 2 was measured with an ellipsometer and found to be 534 nm.

(2) Measurement of phase difference and three-dimensional refractive index of vertically aligned liquid crystal cured film 1 In order to measure the phase difference value of the vertically aligned liquid crystal cured film 1, a vertically aligned film and a vertically aligned liquid crystal cured film were produced on a COP film (ZF-14) manufactured by Zeon Corporation in the same manner as above, and the vertically aligned liquid crystal cured film was bonded to glass via an adhesive (Lintec pressure-sensitive adhesive 15 μm), and after confirming that there was no phase difference in the COP, the phase difference value was measured by changing the incident angle of light on the sample using an ellipsometer. The phase difference values calculated from the obtained film thickness, average refractive index, and ellipsometer measurement results were R ₀ (550) = 1.3 nm, R ₄₀ (550) = 21.9 nm, Rth (450) = -91 nm, Rth (550) = -84 nm, and Rth (450) / Rth (550) = 1.09. The three-dimensional refractive indices n3x, n3y and n3z at 589 nm were calculated from the average refractive index and phase difference value obtained by the ellipsometer. The results are shown in Table 3.

(3) Manufacture of laminate 3 consisting of substrate, vertical alignment film, and vertical alignment liquid crystal cured film 2 The composition 2 for forming a vertical alignment film was applied by a bar coater onto a substrate subjected to corona treatment in the same manner as described above, and dried at 80° C. for 1 minute to obtain a vertical alignment film. The thickness of the obtained vertical alignment film was measured by an ellipsometer and found to be 50 nm.

Subsequently, the composition 2 for forming a vertically aligned liquid crystal cured film was applied to the obtained vertically aligned film using a bar coater, and after drying at 120°C for 1 minute, a high pressure mercury lamp ("Unicure VB-15201BY-A", A vertically aligned liquid crystal cured film 2 is formed by irradiating ultraviolet rays (integrated light amount at a wavelength of 365 nm in a nitrogen atmosphere: 500 mJ/cm ² ) using a UV light source (manufactured by Denki Co., Ltd.). A laminate 3 consisting of the oriented liquid crystal cured film 2 was obtained. The film thickness of the vertically aligned liquid crystal cured film 2 in the obtained laminate 3 was measured with an ellipsometer and found to be 1.2 μm.

(4) Measurement of phase difference and three-dimensional refractive index of vertically aligned liquid crystal cured film 2 In order to measure the phase difference value of the vertically aligned liquid crystal cured film 2, a vertically aligned film and a vertically aligned liquid crystal cured film were produced on a COP film (ZF-14) manufactured by Zeon Corporation in the same manner as above, and the vertically aligned liquid crystal cured film was bonded to glass via an adhesive (Lintec pressure-sensitive adhesive 15 μm), and after confirming that there was no phase difference in the COP, the phase difference value was measured by changing the angle of incidence of light on the sample using an ellipsometer. The obtained film thickness, average refractive index, and phase difference value calculated from the measurement results of the ellipsometer were Rth (450) = -63 nm, Rth (550) = -73 nm, and Rth (450) / Rth (550) = 0.85, respectively. The three-dimensional refractive indexes n3x, n3y, and n3z at 589 nm were obtained from the average refractive index and phase difference value obtained by the ellipsometer. The results are shown in Table 3.

7. Preparation of a laminate including a horizontally aligned liquid crystal cured film, a pressure-sensitive adhesive layer and a vertically aligned liquid crystal cured film (1) Example 1
(a) Preparation of Laminate (Elliptical Polarizing Plate) The cycloolefin film side of the polarizing film prepared above and the horizontally aligned liquid crystal cured film 1 side of the laminate 1 consisting of the substrate, the horizontally aligned film, and the horizontally aligned liquid crystal cured film 1 were laminated via an adhesive (15 μm pressure-sensitive adhesive manufactured by Lintec Corporation), and then the substrate was peeled off together with the horizontally aligned film. Next, the vertically aligned liquid crystal cured film 1 side of the laminate 2 consisting of the substrate, the vertically aligned film, and the vertically aligned liquid crystal cured film 1 was subjected to corona treatment, and then the adhesive A described in Table 1 was applied, and the coated surface of the adhesive A and the horizontally aligned liquid crystal cured film 1 side of the laminate 1 were laminated, and ultraviolet light was irradiated from the vertically aligned liquid crystal cured film 1 side with an integrated light amount of 400 mJ/cm ² (UV-B) using an ultraviolet irradiation device [manufactured by Fusion UV Systems Co., Ltd.] to cure the adhesive A. Thereafter, the base material used for preparing the vertically aligned liquid crystal cured film 1 was peeled off together with the vertically aligned film, thereby obtaining a laminate (elliptically polarizing plate) having a laminated structure of polarizing film/adhesive/horizontally aligned liquid crystal cured film 1/adhesive layer/vertically aligned liquid crystal cured film 1.
The thickness of the adhesive layer measured with a contact type film thickness meter was 1.4 μm.

(b) Evaluation of interference unevenness The laminate (elliptically polarizing plate) prepared above was attached to an aluminum reflector plate via an acrylic adhesive (film thickness 25 μm), and visually observed from an oblique direction under a three-wavelength fluorescent lamp and rotated 360°, and evaluated based on the following criteria. The evaluation results are shown in Table 3.
A: No visible interference unevenness B: Slight visible interference unevenness C: Visible interference unevenness

(2) Example 2
A laminate (elliptically polarizing plate) was produced in the same manner as in Example 1, except that the adhesive was changed to adhesive B, and evaluation of interference unevenness was carried out. The results are shown in Table 3.

(3) Example 3
A laminate (elliptically polarizing plate) was produced in the same manner as in Example 1, except that the adhesive was changed to Adhesive C, and interference unevenness was evaluated. The results are shown in Table 3.

(4) Example 4
A laminate (elliptically polarizing plate) was produced in the same manner as in Example 1, except that the adhesive was changed to Adhesive D and the laminate 2 was changed to a laminate 3, and interference unevenness was evaluated. The results are shown in Table 3.

(5) Comparative example 1
A laminate (elliptically polarizing plate) was produced in the same manner as in Example 1, except that the adhesive was changed to adhesive D, and interference unevenness was evaluated. The results are shown in Table 3.

(6) Comparative example 2
A laminate (elliptically polarizing plate) was produced in the same manner as in Example 1, except that the adhesive was changed to adhesive E, and interference unevenness was evaluated. The results are shown in Table 3.

(7) Comparative example 3
A laminate (elliptically polarizing plate) was produced in the same manner as in Example 1, except that the adhesive was changed to adhesive F, and interference unevenness was evaluated. The results are shown in Table 3.

According to the present invention, the occurrence of interference unevenness is suppressed in the laminates (Examples 1 to 4) in which the difference between the in-plane refractive index of the vertically aligned liquid crystal cured film and the in-plane refractive index of the adhesive layer is controlled. This was confirmed.

Claims (3)

A horizontally aligned liquid crystal cured film, an adhesive layer and a vertically aligned liquid crystal cured film are present adjacent to each other in this order,
The horizontally aligned liquid crystal cured film is a film obtained by curing a polymerizable liquid crystal compound containing a compound represented by the following formula (X) in an oriented state, and which satisfies the following formulas (2) and (3). can be,
The adhesive layer is formed from an active energy ray-curable adhesive, and has a thickness of 0.1 μm or more and 2 μm or less,
A laminate in which the in-plane refractive index of the pressure-sensitive adhesive layer and the in-plane refractive index of the vertically aligned liquid crystal cured film satisfy the relationship of formula (1).

[In formula (X), Ar represents a divalent group having an aromatic group which may have a substituent,
G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, and hydrogen contained in the divalent aromatic group or divalent alicyclic hydrocarbon group The atom may be substituted with 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, and the divalent The carbon atoms constituting the aromatic group or divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom,
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 from 0 to 3, satisfy the relationship 1≦k+l, and when 2≦k+l, B ¹ and B ² , G ¹ and G ² are the same as each other, and may be different, may be different,
E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, and the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and the - contained in the alkanediyl group CH ₂ - may be substituted with -O-, -S-, -C(=O)-, P ¹ and P ² independently represent a polymerizable group or a hydrogen atom, and at least one is a polymerizable group. ]
|((n2x+n2y)/2)-((n3x+n3y)/2)|≦0.03 (1)
[In formula (1), n2x represents the refractive index at wavelength λnm in the direction that produces the maximum refractive index within the plane of the adhesive layer, and n2y is within the same plane as n2x and perpendicular to the direction of n2x. n3x represents the refractive index at wavelength λnm in the direction in which the maximum refractive index occurs in the plane of the vertically aligned liquid crystal cured film, and n3y represents the refractive index at wavelength λnm in the direction in which the maximum refractive index occurs in the plane of the vertically aligned liquid crystal cured film. It represents the refractive index at a wavelength λ nm in a direction perpendicular to the direction. ]
Re(450)/Re(550)≦1.00 (2)
100nm<Re(550)<160nm (3)
[In formulas (2) and (3), Re (λ) represents an in-plane retardation value of a horizontally aligned liquid crystal cured film at a wavelength of λ nm. ] The laminate according to claim 1 , wherein the vertically aligned liquid crystal cured film satisfies formulas (4) and (5).
n3x≒n3y<n3z (4)
-150nm<Rth(550)<-30nm (5)
[In formula (4), n3x represents the refractive index at wavelength λnm in the direction that produces the maximum refractive index in the plane of the vertically aligned liquid crystal cured film, and n3y is the refractive index in the same plane as n3x and perpendicular to the direction of n3x. n3z represents the refractive index at wavelength λnm in the direction of the vertical alignment liquid crystal cured film, and ≒ represents the refractive index at wavelength λnm in the film thickness direction of the vertically aligned liquid crystal cured film, and ≒ represents that the difference in the refractive index between the two is 0.01 or less. ,
In formula (5), Rth (550) represents the retardation value in the thickness direction at a wavelength of 550 nm of the vertically aligned liquid crystal cured film. ] An elliptically polarizing plate comprising the laminate according to claim 1 or 2 laminated with a polarizing film.