Optical stack

Abstract

To provide a long-sized optical laminate including an optical anisotropic layer, less likely to generate blocking even in a rolled state.SOLUTION: The long-sized optical laminate comprises a substrate layer, and an optical anisotropic layer arranged on one surface of the substrate layer. Coefficient of dynamic friction between a surface of the substrate layer opposite the optical anisotropic layer and a surface of the optical anisotropic layer opposite the substrate layer is 0.7 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to an optical laminate. [Background technology]

[0002] In image display devices such as liquid crystal displays and organic electroluminescent (EL) displays, it is known that anti-reflective performance is improved by using a circular polarizer containing a linear polarizer and a phase difference layer for the purpose of optical compensation or to suppress the reduction in visibility due to the reflection of ambient light [for example, Japanese Patent Application Publication No. 2020-134934 (Patent Document 1)]. As the phase difference layer, a liquid crystal cured phase difference layer, which is a cured layer of a polymerizable liquid crystal compound, may be used. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-134934 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The film material used in the manufacture of circular polarizers is usually provided as a long roll of film. An example of the film material is an optical laminate having the phase difference layer described above.

[0005] The object of the present invention is to provide an optical laminate comprising an optically anisotropic layer that is less prone to blocking (adhesion of films) even when rolled up. [Means for solving the problem]

[0006] The present invention provides the following optical laminate. [1] A long optical laminate, The optical laminate includes a substrate layer and an optically anisotropic layer disposed on one surface thereof. An optical laminate in which the coefficient of dynamic friction between the surface of the substrate layer opposite to the optical anisotropy layer and the surface of the optical anisotropy layer opposite to the substrate layer is 0.7 or less. [2] The optical laminate according to [1], wherein the maximum height difference Sz of the surface of the substrate layer opposite to the optical anisotropy layer is 500 nm or less. [3] The optical laminate according to [1] or [2], wherein the optical anisotropy layer comprises a polymer component containing fluorine atoms or silicon atoms. [4] The optical laminate according to any one of [1] to [3], wherein the optical anisotropic layer has reverse wavelength dispersion properties. [5] The optical laminate according to any one of [1] to [4], wherein the optical anisotropy layer has an in-plane phase difference value of 100 nm or more and 160 nm or less for light with a wavelength of 550 nm. [6] The optical laminate according to any one of [1] to [5], wherein the optical anisotropic layer has an optical axis oblique to the longitudinal direction of the substrate layer. [7] The optical laminate according to any one of [1] to [6], wherein the optical anisotropy layer has a thickness of 0.1 μm or more and 5 μm or less. [8] The optical laminate according to any one of [1] to [7], wherein the base layer comprises a (meth)acrylic resin layer. [9] The substrate layer and the optical anisotropy layer further include an orientation layer, The optical laminate according to any one of [1] to [8], wherein the orientation layer is a photo-alignment film made of a photo-oriented polymer containing photoreactive groups. [Effects of the Invention]

[0007] This invention provides a long optical laminate comprising an optically anisotropic layer that is less prone to blocking even when rolled up. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing an example of the layer structure of an optical laminate. [Figure 2] This is a schematic cross-sectional view showing another example of the layer structure of an optical laminate. [Figure 3] This is a schematic cross-sectional view illustrating the amount of winding misalignment. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments. All drawings below are provided to aid in understanding the present invention, and the size and shape of each component shown in the drawings do not necessarily correspond to the size and shape of the actual components.

[0010] <Optical laminate> (1) Configuration of the optical laminate Figure 1 is a schematic cross-sectional view showing an example of the layer structure of an optical laminate according to the present invention (hereinafter also simply referred to as "optical laminate"). The optical laminate 1 shown in Figure 1 includes a base layer 10 and an optical anisotropy layer (hereinafter also referred to as "phase difference layer") 11 disposed on one surface thereof. An alignment layer 12 may be interposed between the base layer 10 and the optical anisotropy layer 11. The optical anisotropy layer 11 and the alignment layer 12 are usually in contact.

[0011] Figure 2 is a schematic cross-sectional view showing an example of the layer structure of an optical laminate. As shown in the optical laminate 2 in Figure 2, the optical laminate may further include a primer layer 13 between the substrate layer 10 and the optical anisotropy layer 11.

[0012] The optical laminate is a long (strip-shaped) laminated film. The length of the optical laminate is, for example, 500m to 20,000m, or 800m to 15,000m. The width of the optical laminate is, for example, 0.5m to 3m, or 0.8m to 2m.

[0013] Optical laminates can be used, for example, as components for manufacturing circular polarizers. Circular polarizers can be applied to image display devices such as liquid crystal displays and organic EL displays. Circular polarizers are typically placed on the viewing side of image display elements such as liquid crystal displays and organic EL displays. The term "circular polarizer" includes elliptic polarizers.

[0014] The coefficient of dynamic friction between surface A of the base layer 10 opposite to the optical anisotropy layer 11 and surface B of the optical anisotropy layer 11 opposite to the base layer 10 is 0.7 or less. Because the coefficient of dynamic friction is within this range, blocking, a phenomenon in which surfaces A and B stick together when a long optical laminate is placed in a rolled state, can be prevented or suppressed. Blocking generally occurs when the roll is placed under high temperature or high temperature and high humidity conditions, but the optical laminate according to the present invention makes it possible to prevent or suppress blocking even under such conditions. Here, "rolled state" refers to a state in which the material is wound up so that the surface A of the base layer 10 opposite to the optical anisotropy layer 11 is in contact with the surface B of the optical anisotropy layer 11 opposite to the base layer 10.

[0015] From the viewpoint of more effectively preventing or suppressing blocking, the coefficient of dynamic friction is preferably 0.68 or less, more preferably 0.65 or less, even more preferably 0.60 or less, still more preferably 0.58 or less, and particularly preferably 0.55 or less. The coefficient of dynamic friction is usually 0.2 or more, and may be 0.3 or more.

[0016] The above coefficient of dynamic friction is measured in accordance with JIS K7125:1999. In this specification, the coefficient of dynamic friction is the coefficient of dynamic friction at 25°C.

[0017] The maximum height difference Sz of the surface A on the side of the base layer 10 opposite to the optical anisotropy layer 11 is preferably 500 nm or less. Having the maximum height difference Sz of surface A within the above range is advantageous in preventing or suppressing winding misalignment that may occur when a long optical laminate is placed in a roll state. Winding misalignment refers to the phenomenon in which, when a material is wound into a roll state in the desired winding shape and left to stand, the roll shape gradually collapses and the positions of both short sides in the width direction shift from the desired positions. Figure 3 is a cross-sectional view of a rolled optical laminate schematically illustrating the amount of winding misalignment. In Figure 3, the elongated optical laminate 100 is wound around a winding core 200. The amount of winding misalignment 105 refers to the distance between a predetermined position 101 and the position 102 where the distance from the predetermined position 101 is maximum among the positions on both short sides in the width direction where winding misalignment occurs. Note that the position 102 where the distance from the predetermined position 101 is maximum is not necessarily located in the outermost layer of the wound optical laminate; the position 102 may also be located in an internal layer.

[0018] From the viewpoint of more effectively preventing or suppressing winding misalignment, the above maximum height difference Sz is more preferably 450 nm or less, even more preferably 400 nm or less, even more preferably 390 nm or less, and particularly preferably 350 nm or less. The above maximum height difference Sz is usually 50 nm or more, and may be 100 nm or more.

[0019] The maximum height difference Sz of surface A can be measured using a non-contact surface shape measuring device. Five arbitrary points are selected from a 94 μm × 70 μm measurement field, and the average of the maximum height differences measured at these five points is defined as the maximum height difference Sz of surface A. In this specification, the maximum height difference is defined as the distance in the height direction between the highest and lowest points on surface A.

[0020] The elements that constitute or can constitute the optical laminate are described in detail below. (2) Base material layer As the base layer 10, a translucent (preferably optically transparent) film formed from a thermoplastic resin can be used.

[0021] Examples of thermoplastic resins include cellulose resins such as triacetylcellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyethersulfone resins; polysulfone resins; polycarbonate resins; polyamide resins such as nylon and aromatic polyamides; polyimide resins; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; cyclic polyolefin resins having cyclo and norbornene structures (also called norbornene resins); (meth)acrylic resins; polyarylate resins; polystyrene resins; polyvinyl alcohol resins; and mixtures thereof. In this specification, "(meth)acrylic" means either acrylic or methacrylic. The "(meth)" in (meth)acrylate, (meth)acryloyl, etc., has the same meaning.

[0022] In particular, from the viewpoint of processability, the thermoplastic resin constituting the base layer 10 is preferably selected from cellulose resin, polyester resin, cyclic polyolefin resin, and (meth)acrylic resin, and more preferably selected from cyclic polyolefin resin and (meth)acrylic resin. In one preferred embodiment, the base layer 10 includes a (meth)acrylic resin layer, and the base layer 10 may consist of a (meth)acrylic resin layer.

[0023] The substrate layer 10 is preferably a film that has no phase difference or has a small phase difference value. Specifically, the in-plane phase difference value of the substrate layer 10 at a wavelength of 550 nm is preferably 0 nm or more and 10 nm or less, and the phase difference value in the thickness direction at a wavelength of 550 nm is preferably -10 nm or more and +10 nm or less. The substrate layer 10 may further have a primer layer 13 between it and the optical anisotropy layer 11.

[0024] While a thinner base layer 10 is preferable for practical handling, if it is too thin, its strength decreases and it tends to have poor processability. The thickness of the base layer 10 is preferably 2 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, and may be 30 μm or more. The thickness of the base layer 10 is preferably 150 μm or less, more preferably 100 μm or less, even more preferably 80 μm or less, and still more preferably 60 μm or less, and may be 50 μm or less.

[0025] The base layer 10 may contain additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, fillers, pigments, and colorants.

[0026] The base layer 10 containing (meth)acrylic resin may contain rubber particles as a filler. The inclusion of rubber particles can increase the toughness of the base layer 10. Furthermore, these rubber particles can be used as a filler in a process to impart irregularities to surface A, which will be described later.

[0027] The rubber particles are rubber elastic particles containing a layer that exhibits rubber elasticity. The rubber particles may consist only of a layer that exhibits rubber elasticity, or they may be multilayer particles having a layer that exhibits rubber elasticity along with other layers. Examples of rubber elastic materials include olefin-based elastic polymers, diene-based elastic polymers, styrene-diene-based elastic copolymers, and acrylic-based elastic polymers. Among these, acrylic-based elastic polymers are preferably used from the viewpoint of light resistance and transparency of the base layer 10.

[0028] The acrylic elastic polymer may be a polymer mainly composed of alkyl acrylate, that is, a polymer containing 50% by mass or more of alkyl acrylate-derived structural units based on the total amount of monomers. The acrylic elastic polymer may be a homopolymer of alkyl acrylate, or it may be a copolymer containing 50% by mass or more of alkyl acrylate-derived structural units and 50% by mass or less of structural units derived from other polymerizable monomers.

[0029] The alkyl acrylates used to constitute acrylic elastic polymers typically have 4 to 8 carbon atoms in their alkyl group. Other polymerizable monomers include, for example, alkyl methacrylates such as methyl methacrylate and ethyl methacrylate; styrene monomers such as styrene and alkylstyrene; monofunctional monomers such as unsaturated nitriles such as acrylonitrile and methacrylonitrile; and polyfunctional monomers such as alkenyl esters of unsaturated carboxylic acids such as allyl (meth)acrylate and metharyl (meth)acrylate; dialkenyl esters of dibasic acids such as diallyl maleate; and unsaturated carboxylic acid diesters of glycols such as alkylene glycol di(meth)acrylate.

[0030] The rubber particles containing the acrylic elastic polymer are preferably multilayer particles having a layer of the acrylic elastic polymer. Specifically, examples include a two-layer structure having a hard polymer layer mainly composed of alkyl methacrylate on the outside of the acrylic elastic polymer layer, and a three-layer structure having a hard polymer layer mainly composed of alkyl methacrylate on the inside of the acrylic elastic polymer layer. The alkyl methacrylate is preferably methyl methacrylate.

[0031] Preferably, the average particle size of the rubber particles, including the rubber elastic layer (layer of acrylic elastic polymer) contained within them, is in the range of 10 nm to 350 nm. More preferably, the average particle size is 30 nm or more, even more preferably 50 nm or more, and even more preferably 320 nm or less, and even more preferably 300 nm or less.

[0032] The average particle size up to the rubber elastic layer (layer of acrylic elastic polymer) in rubber particles can be measured as follows. Specifically, when such rubber particles are mixed with a (meth)acrylic resin to form a film, and its cross-section is stained with an aqueous solution of ruthenium oxide, only the rubber elastic layer is colored and observed in a nearly circular shape, while the (meth)acrylic resin of the base layer is not stained. Then, a thin section is prepared from the film cross-section stained in this way using a microtome or the like, and observed with an electron microscope. Then, 100 stained rubber particles are randomly selected, and after calculating the particle diameter (diameter up to the rubber elastic layer) of each particle, the number average value is taken as the average particle size. Because the measurement is performed in this way, the average particle size obtained is the number average particle size.

[0033] When a rubber particle has a hard polymer mainly composed of methyl methacrylate as its outermost layer, encasing a rubber elastic layer (a layer of acrylic elastic polymer), mixing it with a (meth)acrylic resin base results in the outermost layer of the rubber particle becoming mixed with the (meth)acrylic resin base. Therefore, when its cross-section is stained with ruthenium oxide and observed under an electron microscope, the rubber particle is observed as a particle with its outermost layer removed. Specifically, in the case of a two-layer rubber particle with an acrylic elastic polymer inner layer and a hard polymer mainly composed of methyl methacrylate as the outer layer, the acrylic elastic polymer portion of the inner layer is stained and observed as a single-layer particle. Furthermore, in the case of rubber particles with a three-layer structure in which the innermost layer is a hard polymer mainly composed of methyl methacrylate, the middle layer is an acrylic elastic polymer, and the outermost layer is a hard polymer mainly composed of methyl methacrylate, the particle will be observed as a two-layer structure in which the central part of the innermost layer is not stained, and only the acrylic elastic polymer portion of the middle layer is stained.

[0034] The rubber particle content is preferably 10 parts by mass or more and 45 parts by mass or less, more preferably 15 parts by mass or more and 40 parts by mass or less, and even more preferably 15 parts by mass or more and 35 parts by mass or less, per 100 parts by mass of (meth)acrylic resin (A).

[0035] The surface A of the base layer 10 is preferably surface-treated so that the coefficient of dynamic friction is within the above range, and more preferably so that the maximum height difference Sz is within the above range. Examples of surface treatments include treatments that impart irregularities to the surface A by incorporating a filler into the base layer 10, release treatments, blasting treatments, embossing treatments, etc. Two or more surface treatments may be combined. The release treatment is a treatment that forms a release layer by coating with a release-possessing component, and examples of release-possessing components include fluorine compounds and silicone compounds.

[0036] Processes that create unevenness using fillers, blasting, and embossing tend to reduce the coefficient of dynamic friction and increase Sz. Release treatments also tend to reduce the coefficient of dynamic friction and decrease Sz.

[0037] (3) Primer layer As shown in Figure 2, the optical laminate may further include a primer layer 13 between the substrate layer 10 and the optical anisotropy layer 11. The primer layer 13 is usually laminated directly onto the surface of the substrate layer 10 on the side of the optical anisotropy layer 11. The formation of the primer layer 13 can improve the adhesion between the substrate layer 10 and the orientation layer 12, improve the hardness of the substrate layer, improve the orientation of the orientation layer, and improve the coatability of the composition for the orientation layer (suppression of repelling).

[0038] The main components of the primer layer 13 include epoxy polymers, acrylic polymers, urethane polymers, polyimide polymers, and aramid polymers. It can be formed by applying a primer composition, in which polymer components are dissolved in a solvent, onto a substrate and drying it, or by applying a primer composition containing polymerizable material onto a substrate and curing it by irradiation with active energy rays or thermal energy.

[0039] Examples of primer compositions include those containing epoxy polymers, acrylic polymers, urethane polymers, polyimide polymers, aramid polymers, and the like.

[0040] The primer composition may further contain solvents, additives, etc. Examples of additives include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, and antifouling agents.

[0041] The thickness of the primer layer 13 is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 3 μm or more, and may be 4 μm or more. Furthermore, the thickness of the primer layer 13 is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less.

[0042] (4) Optical anisotropy layer and orientation layer The optically anisotropic layer (phase difference layer) 11 is formed by coating a composition containing a polymerizable liquid crystal compound (hereinafter also referred to as the "phase difference layer forming composition") onto a transparent substrate, and is a layer made of an oriented polymer of the polymerizable liquid crystal compound. The optically anisotropic layer 11 is typically a layer cured with polymerizable liquid crystal compounds in an oriented state. In order to create a phase difference within the viewing surface, the polymerizable liquid crystal compound must be a cured film in which polymerizable groups are polymerized with the polymerizable groups oriented horizontally to the substrate surface. In this case, if the polymerizable liquid crystal compound is a rod-shaped liquid crystal, a positive A plate is sufficient, and if the polymerizable liquid crystal compound is a disc-shaped liquid crystal, a negative A plate is sufficient. Alternatively, chiral agents or the like may be added to the rod-shaped liquid crystal to create a helical orientation.

[0043] The optical anisotropy layer 11 is preferably a λ / 4 layer, a λ / 2 layer, or a positive C layer. The optical anisotropy layer 11 may contain two or more optical anisotropy layers. Examples of combinations of two or more optical anisotropy layers include a combination of a λ / 4 layer and a λ / 2 layer, or a combination of a λ / 4 layer and a positive C layer. If the optical anisotropy layer 11 contains two or more optical anisotropy layers, the optical anisotropy layer 11 may also contain a bonding layer (adhesive layer or bonding agent layer) for bonding these optical anisotropy layers to each other.

[0044] The optically anisotropic layer 11 preferably satisfies the optical properties shown in the following formula (1) for the in-plane phase difference Re(λ) with respect to light of wavelength λnm, and more preferably satisfies the optical properties shown in the following formulas (1), (2), and (3). 100nm <Re(550)<160nm ···(1) (In the formula, Re(550) represents the in-plane phase difference value (in-plane retardation) for light with a wavelength of 550 nm.) Re(450) / Re(550)≦1.0 (2) 1.00≦Re(650) / Re(550) ···(3) (In the formula, Re(450) represents the in-plane phase difference value for light with a wavelength of 450 nm, Re(550) represents the in-plane phase difference value for light with a wavelength of 550 nm, and Re(650) represents the in-plane phase difference value for light with a wavelength of 650 nm.)

[0045] The optical anisotropy layer 11 preferably has inverse wavelength dispersion, and more specifically, it is preferable that it satisfies formulas (2) and (3). When the "Re(450) / Re(550)" of the optical anisotropy layer 11 exceeds 1.0, the light leakage on the short wavelength side in the elliptic polarizer equipped with the optical anisotropy layer increases. Preferably, it is 0.7 to 1.0, more preferably 0.80 to 0.95, even more preferably 0.80 to 0.92, and particularly preferably 0.82 to 0.88. The value of "Re(450) / Re(550)" can be arbitrarily adjusted by adjusting the mixing ratio of the polymerizable liquid crystal compound and the stacking angle and phase difference value of the multiple optical anisotropy layers 11.

[0046] The in-plane phase difference value of the optically anisotropic layer 11 can be adjusted by the thickness of the optically anisotropic layer 11. Since the in-plane phase difference value is determined by the following equation (4), to obtain a desired in-plane phase difference value (Re(λ)), it is necessary to adjust Δn(λ) and the film thickness d. The thickness of the optically anisotropic layer 11 can be measured using an interferometer, laser microscope, or stylus-type film thickness gauge. Note that Δn(λ) depends on the molecular structure of the polymerizable liquid crystal compound, which will be described later. Re(λ) = d × Δn(λ) ... (4) (In the formula, Re(λ) represents the in-plane phase difference value at wavelength λnm, d represents the film thickness, and Δn(λ) represents the birefringence at wavelength λnm.)

[0047] Furthermore, the positive C layer typically has a phase difference value Rth(550) in the thickness direction at a wavelength of 550 nm in the range of -170 nm to -10 nm, preferably -150 nm to -20 nm, and more preferably -100 nm to -40 nm. If the phase difference value in the thickness direction is within this range, the anti-reflective properties from oblique directions can be further improved.

[0048] Examples of polymerizable liquid crystal compounds include rod-shaped polymerizable liquid crystal compounds and disc-shaped polymerizable liquid crystal compounds. Either one of these may be used, or a mixture containing both may be used. When a rod-shaped polymerizable liquid crystal compound is oriented horizontally or vertically with respect to the substrate layer 10, the optical axis of the polymerizable liquid crystal compound coincides with the longitudinal axis of the polymerizable liquid crystal compound. When a disc-shaped polymerizable liquid crystal compound is oriented, the optical axis of the polymerizable liquid crystal compound exists in a direction perpendicular to the disc surface of the polymerizable liquid crystal compound. As a rod-shaped polymerizable liquid crystal compound, for example, those described in Japanese Patent Publication No. 11-513019 (Claim 1, etc.) can be suitably used. As a disc-shaped polymerizable liquid crystal compound, those described in Japanese Patent Application Publication No. 2007-108732 (paragraphs

[0020] to

[0067] , etc.) and Japanese Patent Application Publication No. 2010-244038 (paragraphs

[0013] to

[0108] , etc.) can be suitably used.

[0049] For an optically anisotropic layer formed by polymerizing a polymerizable liquid crystal compound to exhibit an in-plane phase difference, the polymerizable liquid crystal compound should be oriented in a suitable direction. When the polymerizable liquid crystal compound is rod-shaped, an in-plane phase difference is exhibited by oriented the optical axis of the polymerizable liquid crystal compound horizontally with respect to the longitudinal direction of the substrate layer 10 (the plane of the substrate layer 10), in which case the optical axis direction and the slow phase axis direction coincide. When the polymerizable liquid crystal compound is disc-shaped, an in-plane phase difference is exhibited by oriented the optical axis of the polymerizable liquid crystal compound horizontally with respect to the longitudinal direction of the substrate layer 10 (the plane of the substrate layer 10), in which case the optical axis and the slow phase axis are orthogonal. Alternatively, from the viewpoint of optical compensation, the optically anisotropic layer 11 may have an optical axis oblique to the longitudinal direction of the substrate layer 10 (the plane of the substrate layer 10). The optically anisotropic layer 11 may have an optical axis perpendicular to the longitudinal direction of the substrate layer 10 (the plane of the substrate layer 10). The orientation state of the polymerizable liquid crystal compound (and consequently the orientation of the optical axis of the optically anisotropic layer 11) can be adjusted by the combination of the orientation layer 12 and the polymerizable liquid crystal compound.

[0050] A polymerizable liquid crystal compound is a compound having at least one polymerizable group and possessing liquid crystal properties. When two or more polymerizable liquid crystal compounds are used in combination, it is preferable that at least one of them has two or more polymerizable groups in its molecule. A polymerizable group refers to a group that participates in polymerization reactions, and it is preferable that it be a photopolymerizable group. A photopolymerizable group refers to a group that can participate in polymerization reactions through active radicals or acids generated from a photopolymerization initiator.

[0051] Examples of polymerizable groups include vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, acryloyloxy groups, methacryloyloxy groups, oxyranyl groups, oxetanyl groups, styryl groups, and allyl groups. Among these, acryloyloxy groups, methacryloyloxy groups, vinyloxy groups, oxyranyl groups, and oxetanyl groups are preferred, with acryloyloxy groups being more preferred. The liquid crystalline properties of the polymerizable liquid crystal compound may be either thermotropic or lyotropic, with thermotropic liquid crystals being preferred because they allow for precise control of film thickness. Furthermore, the phase order structure in the thermotropic liquid crystal may be either nematic or smectic.

[0052] As polymerizable liquid crystal compounds, from the viewpoint of exhibiting inverse wavelength dispersion, liquid crystals having a T-shaped or H-shaped mesogenic structure with further birefringence in the direction perpendicular to the long axis of the molecule are preferred, and from the viewpoint of obtaining stronger dispersion, T-shaped liquid crystals are more preferred. Specifically, the structure of a T-shaped liquid crystal is, for example, the following formula (I): [ka] Examples of compounds represented by [the formula shown] are given.

[0053] In formula (I), Ar represents a divalent aromatic group which may have substituents. Preferably, the divalent aromatic group contains at least one of a nitrogen atom, an oxygen atom, or a sulfur atom. If the divalent group Ar contains two or more aromatic groups, the two or more aromatic groups may be linked to each other by single bonds, divalent bonding groups such as -CO-O-, and -O-. G 1 and G 2each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, 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 are each independently a single bond or a divalent linking group. k and l each independently represent an integer of 0 to 3, and satisfy the relationship of 1≦k+l. Here, when 2≦k+l, B 1 and B 2 , G 1 and G 2 may each be the same as or different from each other. E 1 and E 2 each independently represent an alkanediyl group having 1 to 17 carbon atoms, wherein a hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and -CH2- contained in the alkanediyl group may be substituted with -O-, -S- or -COO-, and when there are a plurality of -O-, -S- or -COO-, they are not adjacent to each other. P 1 and P 2 each independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

[0054] G 1 and G 2Each of these is 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 methyl-substituted 1,4-phenylenediyl 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-cyclohexandiyl group. Also, there are multiple G 1 and G 2 Preferably, at least one of them is a divalent alicyclic hydrocarbon group, and L 1 or L 2 G that joins 1 and G 2 It is more preferable that at least one of these is a divalent alicyclic hydrocarbon group.

[0055] L 1 and L 2 Each of these is independently, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a1 Ure 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 ~R a8 Each of these independently represents a single bond or an alkylene group with 1 to 4 carbon atoms, R c and R d L represents an alkyl group with 1 to 4 carbon atoms or a hydrogen atom. 1 and L 2 Each is independently, more preferably a single bond, -OR a2-1 -, -CH2-, -CH2CH2-, -COOR a4-1 -, or OCORa6-1 - is the case here R a2-1 , R a4-1 , R a6-1 Each of these independently represents either a single bond, -CH2-, or -CH2CH2-. 1 and L 2 Each of these is independently, and more preferably, a single bond, -O-, -CH2CH2-, -COO-, -COOCH2CH2-, or OCO-.

[0056] B 1 and B 2 Each of these is independently, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a9 Ure a10 -, -R a11 COOR a12 -, -R a13 OCOR a14 -, or R a15 OC=OOR a16 - is the case here R a9 ~R a16 Each of these independently represents a single bond or an alkylene group with 1 to 4 carbon atoms. 1 and B 2 Each is independently, more preferably a single bond, -OR a10-1 -, -CH2-, -CH2CH2-, -COOR a12-1 -, or OCOR a14-1 - is the case here R a10-1 , R a12-1 , R a14-1 Each of these independently represents either a single bond, -CH2-, or -CH2CH2-. 1 and B 2 Each of these is independently, and more preferably, a single bond, -O-, -CH2CH2-, -COO-, -COOCH2CH2-, -OCO-, or OCOCH2CH2-.

[0057] From the viewpoint of exhibiting inverse wavelength dispersion, k and l are preferably in the range of 2 ≤ k + l ≤ 6, preferably k + l = 4, and more preferably k = 2 and l = 2. A symmetric structure is preferred when k = 2 and l = 2.

[0058] E1 and E 2 Each of these groups is independently preferably an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

[0059] P 1 or P 2 Examples of polymerizable groups represented by include epoxy groups, vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, acryloyloxy groups, methacryloyloxy groups, oxyranyl groups, and oxetanyl groups. Among these, acryloyloxy groups, methacryloyloxy groups, vinyloxy groups, oxyranyl groups, and oxetanyl groups are preferred, with acryloyloxy groups being more preferred.

[0060] It is preferable that Ar has at least one selected from an aromatic hydrocarbon ring which may have substituents, an aromatic heterocycle which may have substituents, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, etc., with benzene rings and naphthalene rings being preferred. Examples of the aromatic heterocycle 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, a mimidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenantholine ring, etc. Among these, it is preferable to have a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is even more preferable to have a benzothiazole group. Furthermore, if Ar contains a nitrogen atom, it is preferable that the nitrogen atom has π electrons.

[0061] In formula (I), the total number of π electrons Nπ contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, even more preferably 14 or more, and particularly preferably 16 or more. It is also preferably 30 or less, more preferably 26 or less, and even more preferably 24 or less.

[0062] Preferred examples of the aromatic group represented by Ar include the following groups.

[0063]

Chemical Formula

[0064] In formulas (Ar-1) to (Ar-23), the asterisk * represents a linking site, and Z 0 , Z 1 and Z 2 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N,N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 12 carbon atoms or an N,N-dialkylsulfamoyl group having 2 to 12 carbon atoms.

[0065] Q 1 , Q 2 and Q 3 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.

[0066] J 1 , and J 2 each independently represent a carbon atom or a nitrogen atom.

[0067] Y 1 , Y 2 and Y 3 each independently represent an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group.

[0068] W 1 and W 2each independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.

[0069] Y 1 , Y 2 and Y 3 Examples of the aromatic hydrocarbon group for 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; a phenyl group and a naphthyl group are preferred, and a phenyl group is more preferred. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 4 to 20 carbon atoms containing at least one hetero atom selected from a nitrogen atom, an oxygen atom and a sulfur atom, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group; and a furyl group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group are preferred.

[0070] Y 1 , Y 2 and Y 3 each may independently be an optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. A polycyclic aromatic hydrocarbon group refers to a fused polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. A polycyclic aromatic heterocyclic group refers to a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

[0071] Z 0 , Z 1 and Z 2 each are preferably 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, and Z 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.

[0072] Q 1 , Q 2 and Q 3 are preferably -NH-, -S-, -NR 2’ -, or -O-, and R2’ A hydrogen atom is preferred. Among these, -S-, -O-, and -NH- are particularly preferred.

[0073] Among formulas (Ar-1) to (Ar-23), formulas (Ar-6) and (Ar-7) are preferred from the viewpoint of molecular stability. In equations (Ar-16) to (Ar-23), Y 1 This is the nitrogen atom and Z to which it is bonded. 0 It may also form an aromatic heterocyclic group. Examples of aromatic heterocyclic groups that Ar may have include those mentioned above, such as a pyrrole ring, imidazole ring, pyrroline ring, pyridine ring, pyrazine ring, pyrimidine ring, indole ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring, etc. This aromatic heterocyclic group may have substituents. Also, Y 1 This is the nitrogen atom and Z to which it is bonded. 0 In addition, the aforementioned substituted polycyclic aromatic hydrocarbon groups or polycyclic aromatic heterocyclic groups may also be used. Examples include benzofuran rings, benzothiazole rings, and benzoxazole rings.

[0074] Among polymerizable liquid crystal compounds, compounds having a maximum absorption wavelength of 300 nm to 400 nm are preferred. When a polymerizable liquid crystal composition contains a photopolymerization initiator, the polymerization reaction and gelation of the polymerizable liquid crystal compound may proceed during long-term storage. However, if the maximum absorption wavelength of the polymerizable liquid crystal compound is 300 nm to 400 nm, even if exposed to ultraviolet light during storage, the generation of reactive species from the photopolymerization initiator and the progression of the polymerization reaction and gelation of the polymerizable liquid crystal compound by these reactive species can be effectively suppressed. Therefore, this is advantageous in terms of the long-term stability of the polymerizable liquid crystal composition and can improve the orientation and uniformity of the film thickness of the resulting liquid crystal cured film. The maximum absorption wavelength of the polymerizable liquid crystal compound can be measured using an ultraviolet-visible spectrophotometer in a solvent. The solvent is a solvent that can dissolve the polymerizable liquid crystal compound, and examples include chloroform.

[0075] The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition is, for example, 70 parts by mass or more and 99.5 parts by mass or less, preferably 80 parts by mass or more and 99 parts by mass or less, more preferably 85 parts by mass or more and 98 parts by mass or less, and even more preferably 90 parts by mass or more and 95 parts by mass or less, per 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 from the viewpoint of the orientation of the resulting optically anisotropic layer. In this specification, the solid content of the polymerizable liquid crystal composition means all components of the polymerizable liquid crystal composition excluding volatile components such as organic solvents.

[0076] The optical laminate may include an alignment layer 12. The alignment layer 12 has an orientation-regulating force that aligns the polymerizable liquid crystal compound in a desired direction. The alignment layer 12 facilitates the liquid crystal orientation of the polymerizable liquid crystal compound. The state of liquid crystal orientation, such as horizontal orientation, vertical orientation, hybrid orientation, and tilted orientation, changes depending on the properties of the alignment layer 12 and the polymerizable liquid crystal compound, and any combination can be arbitrarily selected. For example, if the alignment layer 12 is a material that exhibits horizontal orientation as an orientation restricting force, the polymerizable liquid crystal compound can form horizontal orientation or hybrid orientation, and if it is a material that exhibits vertical orientation, the polymerizable liquid crystal compound can form vertical orientation or tilted orientation. The expressions horizontal, vertical, etc., refer to the direction of the long axis of the oriented polymerizable liquid crystal compound with respect to the optical anisotropy layer plane. For example, vertical orientation means that the long axis of the oriented polymerizable liquid crystal compound is perpendicular to the optical anisotropy layer plane. Here, perpendicular means 90° ± 20° with respect to the optical anisotropy layer plane.

[0077] The orientation restricting force can be arbitrarily adjusted by surface conditions and rubbing conditions if the orientation layer 12 is formed from an orientation polymer, and by polarization irradiation conditions, etc., if it is formed from a photo-oriented polymer. Furthermore, liquid crystal orientation can also be controlled by selecting physical properties such as surface tension and liquid crystalline properties of the polymerizable liquid crystal compound.

[0078] The orientation layer 12 formed between the substrate layer 10 and the optical anisotropy layer 11 is preferably insoluble in the solvent used when forming the optical anisotropy layer 11 on the orientation layer 12, and has heat resistance for solvent removal and heat treatment for liquid crystal orientation. Examples of the orientation layer 12 include an orientation layer made of an orientation polymer, a photo-orientation layer, a groove orientation layer, and a stretched film stretched in the orientation direction. When applied to a long roll-shaped film, a photo-orientation layer is preferred because the orientation direction can be easily controlled.

[0079] The thickness of the orientation layer 12 is typically in the range of 10 nm to 5000 nm, preferably in the range of 10 nm to 1000 nm, and more preferably in the range of 30 nm to 300 nm.

[0080] Examples of oriented polymers used in the rubbing orientation layer include polyamides and gelatins having amide bonds in their molecules, polyimides having imide bonds in their molecules and their hydrolysates such as polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid esters. Among these, polyvinyl alcohol is preferred. These oriented polymers may be used individually or in combination of two or more.

[0081] One method of rubbing involves wrapping a rubbing cloth around a rotating rubbing roll and bringing the film of the oriented polymer, formed on the surface of the substrate layer by applying an oriented polymer composition to the substrate layer and annealing it, into contact with the roll.

[0082] The photo-alignment layer is a photo-alignment film composed of a photo-aligning polymer, photo-aligning oligomer, or photo-aligning monomer containing photoreactive groups. The photo-alignment layer can obtain an orientation-regulating force by irradiating it with polarized light. The photo-alignment layer is preferable because the direction of the orientation-regulating force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

[0083] A photoreactive group is a group that generates liquid crystal alignment ability upon irradiation with light. Specifically, it is a group that generates a photoreaction that is the origin of liquid crystal alignment ability, such as molecular orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodegradation reaction, upon irradiation with light. Among these photoreactive groups, those that cause dimerization reactions or photocrosslinking reactions are preferred in terms of their excellent orientation properties. As photoreactive groups that can generate such reactions, those having unsaturated bonds, especially double bonds, are preferred, and more preferably groups having at least one selected from the group consisting of carbon-carbon double bonds (C=C bonds), carbon-nitrogen double bonds (C=N bonds), nitrogen-nitrogen double bonds (N=N bonds), and carbon-oxygen double bonds (C=O bonds).

[0084] Examples of photoreactive groups having a C=C bond include vinyl groups, polyene groups, stilbene groups, stilbazole groups, stilbazolium groups, chalcone groups, and cinnamoyl groups. Chalcone groups and cinnamoyl groups are preferred from the viewpoint of ease of controlling reactivity and the expression of orientation-regulating power during photo-orientation. Examples of photoreactive groups having a C=N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. Examples of photoreactive groups having an N=N bond include azobenzene groups, azonaphthalene groups, aromatic heterocyclic azo groups, bisazo groups, and formazan groups, as well as those with azoxybenzene as their basic structure. Examples of photoreactive groups having a C=O bond include benzophenone groups, coumarin groups, anthraquinone groups, and maleimide groups. These groups may have substituents such as alkyl groups, alkoxy groups, aryl groups, allyloxy groups, cyano groups, alkoxycarbonyl groups, hydroxyl groups, sulfonic acid groups, and halogenated alkyl groups.

[0085] Furthermore, in order to achieve close adhesion with the substrate layer and the optically anisotropic layer, the polymer side chains having photoreactive groups may also have adhesive groups. Examples of adhesive groups include epoxy groups, oxetane groups, and (meth)acryloyl groups.

[0086] Polarized light can be irradiated either by directly irradiating the film surface with polarized light, or by irradiating the substrate layer with polarized light and allowing it to pass through. Furthermore, it is particularly preferable that the polarized light be substantially parallel. The wavelength of the irradiated polarized light should be in a wavelength range in which the photoreactive groups of the polymer or monomer having photoreactive groups can absorb light energy. Specifically, UV (ultraviolet light) in the wavelength range of 250 nm to 400 nm is particularly preferred. Examples of light sources used for this 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, with high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps being more preferred. These lamps are preferred because they have a high emission intensity of ultraviolet light at a wavelength of 313 nm. Polarized light can be irradiated by passing the light from the light source through a suitable polarizer. Such polarizers can include polarizing filters, polarizing prisms such as Grant-Thomson and Grant-Taylor, or wire grid type polarizers.

[0087] The thickness of the optical anisotropy layer 11 (or each layer if it includes two or more types of optical anisotropy layers) is, for example, 0.1 μm or more, 0.5 μm or more, 1 μm or more, or 2 μm or more. Furthermore, the thickness is preferably 10 μm or less, but may be 8 μm or less, 5 μm or less, or 3 μm or less.

[0088] The optically anisotropic layer can be formed by applying a phase difference layer-forming composition containing a polymerizable liquid crystal compound onto a substrate layer 10, drying it, and polymerizing the polymerizable liquid crystal compound. The phase difference layer-forming composition may also be applied onto an alignment layer 12 formed on the substrate layer 10.

[0089] The phase difference layer forming composition may further contain additives such as a solvent, polymerization initiator, leveling agent, antioxidant, photosensitizer, vertical alignment promoter, and polymerizable non-liquid crystal compound, in addition to the polymerizable liquid crystal compound. Each of these components may be used individually or in combination of two or more.

[0090] A polymerization initiator is a compound capable of initiating a polymerization reaction, such as a polymerizable liquid crystal compound. From the viewpoint of independence from the phase state of the thermotropic liquid crystal, a photopolymerization initiator that generates active radicals upon the action of light is preferred as the polymerization initiator.

[0091] As photopolymerization initiators, known photopolymerization initiators can be used. For example, as photopolymerization initiators that generate active radicals, self-cleaving benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, azo compounds, etc. can be used. Hydrogen abstraction types such as benzophenone compounds, alkylphenone compounds, benzoin ether compounds, benzyl ketal compounds, dibenzosverone compounds, anthraquinone compounds, xanthone compounds, thioxanthone compounds, halogenoacetophenone compounds, dialkoxyacetophenone compounds, halogenobisimidazole compounds, halogenotriazine compounds, triazine compounds, etc. can be used. As photopolymerization initiators that generate acid, iodonium salts and sulfonium salts, etc. can be used. Self-cleaving photopolymerization initiators are preferred from the viewpoint of excellent reaction efficiency at low temperatures, and acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, and oxime ester compounds are particularly preferred.

[0092] The content of the polymerization initiator in the phase difference layer forming composition can be appropriately adjusted according to the type and amount of polymerizable liquid crystal compound, but is usually 0.1 parts by mass to 30 parts by mass, preferably 0.5 parts by mass to 10 parts by mass, and more preferably 0.5 parts by mass to 8 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within the above range, polymerization can be carried out without disturbing the orientation of the polymerizable liquid crystal compound.

[0093] The leveling agent is an additive that adjusts the fluidity of the phase difference layer forming composition and makes the coating film obtained by applying the phase difference layer forming composition flatter. For example, it is preferably a polymer component containing fluorine atoms or silicon atoms or a polyacrylate polymer, and a surfactant mainly composed of a polymer component containing fluorine atoms or silicon atoms is more preferable. Specifically, examples include organic modified silicone oil-based, polyacrylate-based, and perfluoroalkyl-based leveling agents. Among these, polyacrylate-based leveling agents and perfluoroalkyl-based leveling agents are preferred. The content of the leveling agent is preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.05 parts by mass or more and 3 parts by mass or less, and even more preferably 0.05 parts by mass or more and 1 part by mass or less, per 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, it is easy to horizontally orient the polymerizable liquid crystal compound, and the resulting optically anisotropic layer tends to be smoother. If the leveling agent content relative to the polymerizable liquid crystal compound exceeds the above range, the resulting optically anisotropic layer tends to be uneven. The phase difference layer forming composition may contain two or more leveling agents.

[0094] The optically anisotropic layer 11 preferably contains a fluorine atom-containing component. By including a fluorine atom-containing component in the optically anisotropic layer 11, the coefficient of dynamic friction can be easily adjusted to the predetermined range. The fluorine atom-containing component is not particularly limited, but one example is the fluorine-based leveling agent described above. The content of the fluorine atom-containing component is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.05 parts by mass or more and 3 parts by mass or less, per 100 parts by mass of the polymerizable liquid crystal compound. [Examples]

[0095] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" and "parts" in the examples refer to mass percent and parts by mass.

[0096] <Example 1> [1] Manufacturing of the base layer 70% (meth)acrylic resin and 30% rubber particles were mixed in a super mixer and melt-kneaded in a twin-screw extruder to form pellets. As the (meth)acrylic resin, a copolymer of methyl methacrylate / methyl acrylate = 96% / 4% (mass ratio) was used. The rubber particles were elastic particles with a three-layer structure: the innermost layer was a hard polymer polymerized with methyl methacrylate and a small amount of allyl methacrylate; the middle layer was a soft elastic material mainly composed of butyl acrylate, further polymerized with styrene and a small amount of allyl methacrylate; and the outermost layer was a hard polymer polymerized with methyl methacrylate and a small amount of ethyl acrylate. The average particle diameter up to the elastic middle layer was 240 nm. In these rubber particles, the total mass of the innermost and middle layers was 70% of the total particle mass.

[0097] The above pellets were fed into a 65 mm diameter single-screw extruder and extruded through a T-type die at a set temperature of 275°C. The extruded resin was sandwiched between a roughened embossing roll and a rubber elastic roll to obtain a base layer (1). The thickness of the base layer (1) was 80 μm.

[0098] [2] Preparation of composition for forming orientation layer Composition (1) for forming an orientation layer was obtained by mixing the following components and stirring the resulting mixture at 80°C for 1 hour. Photo-oriented material represented by the following formula: 2 parts [ka] Solvent: Cyclopentanone: 98 parts

[0099] [3] Preparation of the composition (1) for forming a phase difference layer The following components were mixed, and the resulting mixture was stirred at 80°C for 1 hour to obtain a phase difference layer forming composition (1). Polymerizable liquid crystal compound represented by the following formula (A11-1): 100 parts [ka] Polymerizable liquid crystal compound (x-1) represented by the following formula: 33 parts [ka] Photopolymerization initiator (2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure® 369; manufactured by BASF Japan): 8 parts Acrylic leveling agent (BYK361N; manufactured by BYK-Chemie): 0.1 part Solvent: Cyclopentanone: 546 parts Solvent N-methylpyrrolidone: 364 parts

[0100] [4] Manufacturing of optical laminates An orientation layer forming composition (1) was applied to the opposite side of the embossed surface of a long substrate layer (1) by die coating to form a first coating film. The obtained first coating film was dried at 80°C for 2 minutes, then cooled to room temperature to form a first dried film. Subsequently, polarized ultraviolet light was irradiated at a rate of 100 mJ (based on 313 nm) such that the direction of the orientation restricting force was at a 45° angle with respect to the transport direction (long direction) of the substrate layer (1) to form a long orientation layer on the substrate layer (1). The polarized ultraviolet light was irradiated onto the first dried film from a direction perpendicular to the long and short directions of the first dried film.

[0101] Next, a phase difference layer forming composition (1) was applied to the elongated orientation layer by die coating to form a second coating film with a thickness of 17 μm. The second coating film was heated and dried at 90°C for 2 minutes and then cooled to room temperature to form a second dried film. An ultraviolet irradiation device was used to expose the film at an exposure dose of 500 mJ / cm². 2 By irradiating the second dried film with ultraviolet light (based on 365 nm), an optical laminate (1) was obtained in which a long optical anisotropic layer was formed.

[0102] [5] Measurement and evaluation [5-1] Measurement of film thickness A sample piece (4 cm × 4 cm) was cut from the optical laminate (1), and its thickness was measured using a laser microscope (LEXT3000; manufactured by Olympus Corporation). As a result, the thickness of the elongated orientation layer was 200 nm, and the thickness of the elongated optical anisotropy layer was 2.1 μm.

[0103] [5-2] Measurement of the coefficient of kinetic friction In accordance with JIS K7125:1999, the coefficient of dynamic friction at 25°C was measured between surface A of the substrate layer opposite to the optically anisotropic layer and surface B of the optically anisotropic layer opposite to the substrate layer. The result showed a coefficient of dynamic friction of 0.62.

[0104] [5-3] Measurement of the surface shape of the substrate layer Using a VertScan device manufactured by Ryoka Systems Co., Ltd., the maximum height difference Sz of surface A on the side opposite the optically anisotropic layer in the substrate layer was measured. Five arbitrary locations were selected from a 94 μm × 70 μm measurement field, and the average of the maximum height differences measured at these five locations was defined as the maximum height difference Sz. As a result, the maximum height difference Sz of surface A was found to be 387 nm.

[0105] [5-4] Evaluation of blocking Two 10cm x 10cm sample pieces were cut from any point on the optical laminate (1), and they were placed on top of each other so that the surface A of the substrate layer and the surface B of the optical anisotropy layer were in contact. They were then heated in an 80°C oven for 10 minutes. After removing them from the oven and cooling, the adhesion area of ​​the two sample pieces was measured and evaluated according to the following criteria. The optical laminate (1) was evaluated as A. A: The area where it was attached was between 0% and less than 20% of the total area. B: The area covered is between 20% and 50% of the total area. C: The area that is covered is 50% or more of the total area.

[0106] [5-5] Evaluation of winding misalignment A 1000m length of optical laminate (1) was wound onto a core with an inner diameter of 152.55mm and an outer diameter of 167mm. The amount of film misalignment was measured according to the definition above and evaluated according to the following criteria. The amount of misalignment of optical laminate (1) was 1.5mm, and the evaluation was A. A: Roll misalignment is less than 2mm B: Roll misalignment of 2mm or more but less than 5mm C: Roll misalignment of 5mm or more

[0107] [5-6] Evaluation of adhesion A sample was cut from an arbitrary location on the optical laminate (1), and the adhesion of the optically anisotropic layer was evaluated according to JIS K5400. The evaluation of the optical laminate (1) was C. A: None of the grids are delaminating. B: The paint film is partially or completely peeling off (1% to less than 50%) C: The paint film is partially or completely peeling off (50% or more).

[0108] <Example 2> When preparing the phase difference layer forming composition (1), 6.7 parts of a compound having the following structure (LALOMER LR9000; manufactured by BASF Japan) were added and mixed, and the resulting mixture was stirred at 80°C for 1 hour to obtain the phase difference layer forming composition (2). Then, an optical laminate (2) was obtained in the same manner as in Example 1, except that the phase difference layer forming composition (2) was used instead of the phase difference layer forming composition (1). [ka]

[0109] <Example 3> A phase difference layer forming composition (3) was obtained in the same manner as in Example 2, except that 0.1 parts of a fluorine-based leveling agent (Megafac F556; manufactured by DIC Corporation) was used instead of 0.1 parts of an acrylic-based leveling agent. Then, an optical laminate (3) was obtained in the same manner as in Example 2, except that a phase difference layer forming composition (3) was used instead of a phase difference layer forming composition (2).

[0110] <Example 4> A phase difference layer forming composition (4) was obtained in the same manner as in Example 2, except that the amount of fluorine-based leveling agent added was changed from 0.1 parts to 0.3 parts. Next, an optical laminate (4) was obtained in the same manner as in Example 2, except that a phase difference layer forming composition (4) was used instead of a phase difference layer forming composition (2).

[0111] <Example 5> A phase difference layer forming composition (5) was obtained in the same manner as in Example 2, except that 0.1 parts of a silicon-based leveling agent (BYK330; manufactured by BYK-Chemie) was used instead of 0.1 parts of an acrylic-based leveling agent. Then, an optical laminate (5) was obtained in the same manner as in Example 2, except that a phase difference layer forming composition (5) was used instead of a phase difference layer forming composition (2).

[0112] <Example 6> [1] Manufacturing of the base layer (Meth)acrylic resins were mixed in a supermixer and then melt-kneaded in a twin-screw extruder to form pellets. As the (meth)acrylic resin, a copolymer of methyl methacrylate / methyl acrylate = 96% / 4% (mass ratio) was used.

[0113] The above pellets were melt-extruded and sandwiched between two mirror-finish rolls to obtain a base layer (2). The thickness of base layer (2) was 40 μm. Furthermore, a release agent was coated on one side of base layer (2) to form a release layer, thereby obtaining base layer (3). The maximum height difference Sz on the surface of the release layer of base layer (3) was 289 nm.

[0114] [2] Manufacturing of optical laminates An elongated orientation layer and an elongated optical anisotropy layer were formed on the surface of the base material layer (3) opposite to the release layer, in the same manner as in Example 3, to obtain an optical laminate (6).

[0115] <Example 7> [1] Manufacturing of the base layer A substrate layer (2) was obtained in the same manner as in Example 4. A sandblasting treatment was performed on one side of the substrate layer (2) by spraying an abrasive to roughen the surface and obtain a substrate layer (4). The maximum height difference Sz of the blasted surface of the substrate layer (4) was 350 nm.

[0116] [2] Manufacturing of optical laminates An elongated orientation layer and an elongated optical anisotropy layer were formed on the surface of the substrate layer (4) opposite to the blast-treated surface in the same manner as in Example 3 to obtain an optical laminate (7).

[0117] <Example 8> [1] Manufacturing of the base layer Sandblasting was performed in the same manner as in Example 5[1], except that the sandblasting conditions were changed, to obtain a substrate layer (5). The maximum height difference Sz of the blasted surface of the substrate layer (5) was 994 nm.

[0118] [2] Manufacturing of optical laminates An elongated orientation layer and an elongated optical anisotropy layer were formed on the surface of the substrate layer (5) opposite to the blast-treated surface in the same manner as in Example 3 to obtain an optical laminate (8).

[0119] <Example 9> [1] Manufacturing of the base layer Sandblasting was performed in the same manner as in Example 5[1], except that the sandblasting conditions were changed, to obtain a substrate layer (6). The maximum height difference Sz of the blasted surface of the substrate layer (6) was 461 nm.

[0120] [2] Manufacturing of optical laminates An elongated orientation layer and an elongated optical anisotropy layer were formed on the surface of the substrate layer (6) opposite to the blast-treated surface in the same manner as in Example 3 to obtain an optical laminate (9).

[0121] <Example 10> [1] Manufacturing of the base layer A substrate layer (7) was obtained by sandblasting one side of a cyclic polyolefin resin film (ZF-14; manufactured by Zeon Corporation, 40 μm thick) in the same manner as in Example 5. The maximum height difference Sz of the blasted surface of the substrate layer (7) was 391 nm.

[0122] [2] Manufacturing of optical laminates An elongated orientation layer and an elongated optical anisotropy layer were formed on the surface of the substrate layer (7) opposite to the blast-treated surface in the same manner as in Example 3 to obtain an optical laminate (10).

[0123] <Comparative Example 1> A cyclic polyolefin resin film (ZF-14; manufactured by Zeon Corporation, 40 μm thick) was used as the base layer (8). An elongated orientation layer and an elongated optical anisotropy layer were formed on one side of the base layer (8) in the same manner as in Example 2 to obtain an optical laminate (11).

[0124] <Comparative Example 2> A biaxially oriented polyethylene terephthalate film (Diafoil, manufactured by Mitsubishi Plastics, 100 μm thick) was used as the base layer (9). An elongated orientation layer and an elongated optical anisotropy layer were formed on one side of the base layer (9) in the same manner as in Example 2 to obtain an optical laminate (12).

[0125] Table 1 shows the measurement results of the dynamic friction coefficient and maximum height difference Sz for each example and comparative example, as well as the evaluation of blocking, winding misalignment, and adhesion.

[0126] [Table 1] [Explanation of Symbols]

[0127] 1,2 Optical laminate, 10 Substrate layer, 11 Optical anisotropy layer, 12 Orientation layer, 13 Primer layer, 100 Optical laminate, 101 Desired position, 102 Position where the distance from the desired position is maximum, 105 Winding misalignment amount, 200 Winding core.

Claims

1. A long optical laminate, The optical laminate includes a substrate layer and an optically anisotropic layer disposed on one surface thereof. The coefficient of dynamic friction between the surface of the substrate layer opposite to the optically anisotropic layer and the surface of the optically anisotropic layer opposite to the substrate layer is 0.7 or less. The substrate layer is a layer selected from the group consisting of a polyester resin layer, a cyclic polyolefin resin layer, and a (meth)acrylic resin layer, or a laminate of the said layer and a release layer disposed on the surface of the said layer opposite to the optically anisotropic layer. An optical laminate in which the thickness of the substrate layer is 5 μm or more.

2. The optical laminate according to claim 1, wherein the maximum height difference Sz of the surface of the substrate layer opposite to the optical anisotropy layer is 500 nm or less.

3. The optical laminate according to claim 1 or 2, wherein the optical anisotropy layer comprises a polymer component containing fluorine atoms or silicon atoms.

4. The optical laminate according to any one of claims 1 to 3, wherein the optical anisotropic layer has reverse wavelength dispersion properties.

5. The optical laminate according to any one of claims 1 to 4, wherein the optical anisotropy layer has an in-plane phase difference value of 100 nm or more and 160 nm or less for light with a wavelength of 550 nm.

6. The optical laminate according to any one of claims 1 to 5, wherein the optical anisotropic layer has an optical axis oblique to the longitudinal direction of the substrate layer.

7. The optical laminate according to any one of claims 1 to 6, wherein the optical anisotropy layer has a thickness of 0.1 μm or more and 5 μm or less.

8. The optical laminate according to any one of claims 1 to 7, wherein the substrate layer includes the (meth)acrylic resin layer.

9. The substrate layer and the optical anisotropy layer further include an orientation layer, The optical laminate according to any one of claims 1 to 8, wherein the orientation layer is a photo-alignment film made of a photo-oriented polymer containing photoreactive groups.

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