Laminated film, method for manufacturing a laminated film, and method for manufacturing an optical laminate.

Abstract

To provide a laminated film that can suppress the occurrence of minute defects in an image display device, a method for manufacturing the laminated film that can be manufactured smoothly, and a method for manufacturing an optical laminate containing the laminated film. [Solution] The laminated film according to an embodiment of the present invention comprises, in this order, a base layer, an orientation-solidified layer of a liquid crystal compound, an adhesive layer, and a release liner. The release liner is attached to the surface of the adhesive layer in the thickness direction. The release liner is peelable from the adhesive layer.

Description

Technical Field

[0001] The present invention relates to a laminated film, a method for manufacturing the laminated film, and a method for manufacturing an optical laminate.

Background Art

[0002] Image display devices represented by liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices, inorganic EL display devices) have been rapidly spreading. In image display devices, a laminated optical film including an alignment fixing layer of a liquid crystal compound may be used. For example, it has been considered to manufacture a laminated optical film in which an alignment fixing layer of a liquid crystal compound is laminated to another optical film via an adhesive layer. As a method for manufacturing such a laminated optical film, for example, after forming an adhesive layer on the surface of a release liner, an optical film is attached to the surface of the adhesive layer opposite to the release liner, then the release liner is peeled off from the adhesive layer, and an alignment fixing layer of a liquid crystal compound is attached to the surface from which the release liner of the adhesive layer has been peeled off (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a laminated optical film manufactured by the method described in Patent Document 1 is applied to an image display device, minute defects such as dot-like interference unevenness (hereinafter sometimes referred to as spot unevenness) may occur. The main object of the present invention is to provide a laminated film that can suppress the occurrence of minute defects in an image display device, a method for manufacturing the laminated film that can be manufactured smoothly, and a method for manufacturing an optical laminate containing the laminated film. [Means for solving the problem]

[0005] [1] A laminated film according to an embodiment of the present invention comprises, in this order, a base layer, an orientation solidified layer of a liquid crystal compound, an adhesive layer, and a release liner. The release liner is attached to the surface of the adhesive layer in the thickness direction. The release liner is peelable from the adhesive layer. [2] In the laminated film described in [1] above, the orientation solidified layer of the liquid crystal compound may be arranged on the surface in the thickness direction of the base layer. The base layer may be peelable from the orientation solidified layer of the liquid crystal compound. [3] In the laminated film described in [1] or [2] above, the dimensions of the orientation solidified layer of the liquid crystal compound in the orthogonal direction perpendicular to the thickness direction may be greater than or equal to the dimensions of the adhesive layer in the orthogonal direction. [4] The laminated film described in any of [1] to [3] above may have a long length. [5] In the laminated film described in any of [1] to [4] above, the orientation solidification layer of the liquid crystal compound may have an in-plane phase difference. [6] In the laminated film described in any of [1] to [5] above, the adhesive layer may contain a (meth)acrylic adhesive. [7] In the laminated film described in any of [1] to [6] above, the substrate layer may be a coating substrate for the orientation solidified layer of the liquid crystal compound. [8] A method for manufacturing a laminated film according to another aspect of the present invention includes the steps of: preparing a first film by forming an orientation solidified layer of a liquid crystal compound on the surface of a substrate layer in the thickness direction; preparing a second film by forming an adhesive layer on the surface of a release liner in the thickness direction; and bonding the first film and the second film by bringing the adhesive layer of the second film into contact with the orientation solidified layer of the liquid crystal compound of the first film. [9] In the method for manufacturing a laminated film described in [8] above, the adhesive layer of the second film may have, in the thickness direction, a first surface on the release liner side and a second surface located away from the first surface. The arithmetic mean roughness Ra of the second surface of the adhesive layer is smaller than the arithmetic mean roughness Ra of the first surface of the adhesive layer.

[10] The method for manufacturing a laminated film described in [8] or [9] above may further include a step of cutting both ends of the laminated film in a direction perpendicular to the lamination direction of the laminated film.

[11] A method for manufacturing an optical laminate according to yet another aspect of the present invention further comprises: the step of manufacturing the laminated film by the method for manufacturing a laminated film described in any of [8] to

[10] above; the step of peeling off the release liner provided on the laminated film from the adhesive layer, and the step of attaching the optical film to the surface of the adhesive layer from which the release liner has been peeled off; and the step of peeling off the substrate layer from the orientation solidification layer of the liquid crystal compound.

[12] In the method for manufacturing an optical laminate described in

[11] above, the optical laminate may include a polarizer. In this case, the refractive index of the orientation solidified layer of the liquid crystal compound in the direction of the transmission axis of the polarizer may exceed 1.55.

[13] In the method for manufacturing the optical laminate described in

[12] above, the optical film may include a polarizer. In this case, the refractive index of the orientation solidified layer of the liquid crystal compound in the direction of the transmission axis of the polarizer may exceed 1.60. [Effects of the Invention]

[0006] According to embodiments of the present invention, it is possible to realize a laminated film that can suppress the occurrence of minute defects in an image display device, a method for manufacturing the laminated film that can be manufactured smoothly, and a method for manufacturing an optical laminate containing the laminated film. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic cross-sectional view of a laminated film according to one embodiment of the present invention. [Figure 2] Figure 2 is a schematic diagram illustrating a first lamination step included in a method for manufacturing a laminated film according to another aspect of the present invention. [Figure 3] Figure 3 is a schematic diagram illustrating the cutting process that follows the first bonding process shown in Figure 1. [Figure 4] Figure 4 is a schematic diagram illustrating a first peeling step included in a method for manufacturing an optical laminate 1 according to yet another aspect of the present invention. [Figure 5] Figure 5 is a schematic diagram illustrating the second bonding process, which follows the first peeling process shown in Figure 4. [Figure 6] Figure 6 is a schematic diagram illustrating the optical film used in the second lamination process shown in Figure 5. [Modes for carrying out the invention]

[0008] The following describes representative embodiments of the present invention, but the present invention is not limited to these embodiments. Furthermore, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc., of each part compared to the embodiments; however, these are merely examples and do not limit the interpretation of the present invention.

[0009] (Definitions of terms and symbols) The definitions of terms and symbols used in this specification are as follows: (1) Refractive index (nx, ny, nz) "nx" is the refractive index in the direction where the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. In the equation of the ellipse (x 2 / a 2 ) + (y 2 / b 2 ) = 1, taking a as nx, b as ny, and x and y as the refractive indices in the x-direction and y-direction at an angle θ on the ellipse, and solving the simultaneous equations from y = x(tanθ) and the above nx and ny, the "refractive index in the transmission axis direction" is obtained by √(x 2 + y 2 ). The "average refractive index" is obtained by (nx + ny + nz) / 3. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane phase difference measured with light of wavelength λ nm at 23°C. For example, "Re(550)" is the in-plane phase difference measured with light of wavelength 550 nm at 23°C. When the thickness of the layer (film) is d (nm), Re(λ) is obtained by the formula: Re(λ) = (nx - ny) × d. (3) Phase difference in the thickness direction (Rth) "Rth(λ)" is the phase difference in the thickness direction measured with light of wavelength λ nm at 23°C. For example, "Rth(550)" is the phase difference in the thickness direction measured with light of wavelength 550 nm at 23°C. When the thickness of the layer (film) is d (nm), Rth(λ) is obtained by the formula: Rth(λ) = (nx - nz) × d. (4) Nz coefficient The Nz coefficient is obtained by Nz = Rth / Re. (5) Angle [[ID=3!]] When referring to an angle in this specification, the angle includes both clockwise and counterclockwise directions with respect to the reference direction. Therefore, for example, "45°" means ±45°. (6) Substantially parallel or orthogonal The expressions "substantially parallel" and "approximately parallel" include cases where the angle between the two directions is within 0°±3°. Furthermore, the expressions "substantially orthogonal" and "approximately orthogonal" include cases where the angle between the two directions is 90°±3°.

[0010] A. Overview of Laminated Films Figure 1 is a schematic cross-sectional view of a laminated film according to one embodiment of the present invention. As shown in Figure 1, in one embodiment, the laminated film 100 comprises a base layer 1, an orientation solidification layer 2 of a liquid crystal compound, an adhesive layer 3, and a release liner 4 in this order. In this specification, "orientation-solidified layer of liquid crystal compound" refers to a layer in which liquid crystal compounds are oriented in a predetermined direction within the layer, and this orientation state is fixed. Furthermore, the concept of "orientation-solidified layer" encompasses the orientation-cured layer obtained by curing liquid crystal monomers, as described later. The adhesive layer 3 has a first surface 3a and a second surface 3b in the thickness direction of the adhesive layer 3 (hereinafter sometimes simply referred to as the thickness direction). The first surface 3a of the adhesive layer 3 is located on the side of the release liner 4. The second surface 3b of the adhesive layer 3 is located on the side of the first liquid crystal alignment solidification layer 2. The release liner 4 is attached to the surface of the adhesive layer 3 in the thickness direction (specifically, the first surface 3a). The release liner 4 can be peeled off from the adhesive layer 3. The inventors of the present invention have discovered that minute defects (typically spot irregularities) that occur when a laminated film comprising an orientation-solidified layer of liquid crystal compound and an adhesive layer is applied to an image display device are caused by the surface shape of the adhesive layer. Therefore, the inventors diligently investigated the relationship between minute defects and the surface shape of the adhesive layer and found that by placing relatively flat surfaces in the adhesive layer closer to the orientation solidification layer of the liquid crystal compound than relatively rough surfaces in the adhesive layer, light interference occurs, which can reduce minute defects (typically spot unevenness) in image display devices. Light interference occurs in thinner layers with stronger interfacial reflection. In other words, light interference is more likely to occur on the surface of thin layers with a high refractive index, such as the oriented solidified layer of a liquid crystal compound. When a rough surface of an adhesive layer is bonded to an oriented solidified layer of a liquid crystal compound, variations in optical path length occur, resulting in interference variations (typically spot variations). In one embodiment, a release liner 4 is attached to the first surface 3a of the adhesive layer 3. Therefore, irregularities are easily formed on the first surface 3a of the adhesive layer 3, due to the components of the release liner 4 and / or foreign matter adhering to the release liner 4. In other words, the first surface 3a of the adhesive layer 3 is relatively rougher than the second surface 3b of the adhesive layer 3. To put it another way, the second surface 3b of the adhesive layer 3 is relatively flatter than the first surface 3a of the adhesive layer 3. In such a laminated film 100, the second surface 3b of the adhesive layer 3 is located closer to the orientation solidification layer 2 of the liquid crystal compound than the first surface 3a. Therefore, when the laminated film 100 is applied to an image display device, light interference can be reduced, and as a result, the occurrence of minute defects (typically spot unevenness) can be suppressed.

[0011] The laminated film 100 may be in the form of a single sheet or in the form of a long strip. In one embodiment, the laminated film 100 is in the form of a long strip. In this specification, "elongated" means an elongated shape in which the lengthwise dimension is longer than the widthwise dimension, which is perpendicular to both the lengthwise and thicknesswise directions. Hereafter, the lengthwise dimension of a film may be simply referred to as length, and the widthwise dimension of a film may be simply referred to as width. The length of an elongated film is, for example, 10 times or more, preferably 20 times or more, than its width.

[0012] B. Details of Laminated Films Next, with reference to Figure 1, the details of a laminated film according to one embodiment will be described.

[0013] B-1. Base material layer The substrate layer 1 supports the oriented solidified layer 2 of the liquid crystal compound. The substrate layer 1 has any suitable configuration. The base layer 1 typically contains a resin material. Examples of resin materials include polyester resins such as polyethylene terephthalate (PET); polyolefin resins such as polyethylene and polypropylene; cycloolefin (COP) resins such as polynorbornene; cellulose resins such as triacetylcellulose (TAC); polycarbonate (PC) resins; and (meth)acrylic resins. Note that "(meth)acrylic resin" refers to acrylic resins and / or methacrylic resins. Resin materials can be used alone or in combination. Among the resin materials, polyester resins and cellulose resins are preferred.

[0014] In one embodiment, the substrate layer 1 is a coating substrate for the first liquid crystal alignment solidification layer 2. One side of the substrate layer 1 in the thickness direction is subjected to an alignment treatment. The alignment-treated surface of the substrate layer 1 is configured to align the liquid crystal compound, which will be described later. Orientation treatments include, for example, mechanical orientation treatments, physical orientation treatments, and chemical orientation treatments.

[0015] The thickness of the substrate layer 1 is, for example, 5 μm to 100 μm, preferably 20 μm to 80 μm. The width of the base layer 1 is, for example, 500 mm to 2000 mm, preferably 1000 mm to 1500 mm.

[0016] B-2. Aligned and solidified layer of liquid crystal compound In one embodiment, the oriented solidified liquid crystal compound layer 2 is located on the surface of the substrate layer 1 in the thickness direction. In the illustrated example, the oriented solidified liquid crystal compound layer 2 is located on the orientation-treated surface of the substrate layer 1. The above-described substrate layer 1 is separable from the alignment and curing layer 2 of the liquid crystal compound (see FIG. 5). Thus, the substrate layer can be removed as needed. Therefore, in the image display device, it is possible to suppress the substrate layer from causing minute defects and to achieve thinning.

[0017] Hereinafter, the alignment and curing layer 2 of the liquid crystal compound may be referred to as the first liquid crystal alignment and curing layer 2. The first liquid crystal alignment and curing layer 2 may have an in-plane retardation or a retardation in the thickness direction. The first liquid crystal alignment and curing layer 2 preferably has an in-plane retardation. The refractive indices of the first liquid crystal alignment and curing layer 2 show, for example, a relationship of nx > ny = nz. Note that "ny = nz" includes not only the case where ny and nz are completely equal but also the case where they are substantially equal. Therefore, within a range not impairing the effects of the present invention, ny > nz or ny < nz may occur. The in-plane retardation Re(550) of the first liquid crystal alignment and curing layer 2 is, for example, 100 nm to 300 nm. The Nz coefficient of the first liquid crystal alignment and curing layer 2 is, for example, 0.9 to 1.5, preferably 0.9 to 1.3. The first liquid crystal alignment and curing layer 2 may function as a λ / 2 plate, or may function as a λ / 3 plate, λ / 4 plate, λ / 5 plate, or C-Plate. In the illustrated example, the first liquid crystal alignment and curing layer 2 functions as a λ / 4 plate. When the first liquid crystal alignment and curing layer 2 functions as a λ / 4 plate, the in-plane retardation Re(550) is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and even more preferably 130 nm to 160 nm.

[0018] In the first liquid crystal alignment and curing layer 2, typically, rod-shaped liquid crystal compounds are aligned in a state of being arranged in a predetermined direction (homogeneous alignment). Examples of the liquid crystal compound include a liquid crystal compound having a nematic liquid crystal phase (nematic liquid crystal). Examples of such a liquid crystal compound include a liquid crystal polymer and a liquid crystal monomer. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination. The mechanism by which liquid crystalline properties are expressed in liquid crystal compounds may be lyotropic or thermotropic.

[0019] When a liquid crystal compound contains a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer or a crosslinkable monomer. The orientation state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (i.e., curing) the liquid crystal monomer. After oriented the liquid crystal monomer, the orientation state can be fixed by polymerizing or crosslinking the liquid crystal monomers together, for example. Here, polymerization forms a polymer and crosslinking forms a three-dimensional network structure, but these are non-liquid crystal. Therefore, the formed first liquid crystal orientation solidified layer does not undergo transitions to liquid crystal phase, glass phase, or crystalline phase due to temperature changes, which is characteristic of liquid crystal compounds. As a result, the first liquid crystal orientation solidified layer can have extremely excellent stability that is unaffected by temperature changes.

[0020] Any suitable liquid crystal monomer can be used. Examples of liquid crystal monomers include polymerizable mesogenic compounds described in Japanese Patent Publication No. 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445. Specific examples of such polymerizable mesogenic compounds include BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Silicon-CC3767. Specific examples of liquid crystal compounds and details of the method for forming the orientation solidified layer are described in Japanese Patent Publication No. 2006-163343. The description in said publication is incorporated herein by reference.

[0021] The thickness of the first liquid crystal alignment solidification layer 2 is arbitrarily and appropriately adjusted so that a desired in-plane phase difference is obtained. The thickness of the first liquid crystal alignment solidification layer 2 is, for example, 5 μm or less, preferably 3 μm or less, and more preferably 2 μm or less. On the other hand, the lower limit of the thickness of the first liquid crystal alignment solidification layer 2 is typically 0.5 μm.

[0022] In one embodiment, the dimensions of the first liquid crystal alignment solidification layer 2 in the orthogonal direction perpendicular to the thickness direction (hereinafter sometimes simply referred to as the orthogonal direction) are greater than or equal to the dimensions of the adhesive layer 3 in the orthogonal direction. In particular, the width of the first liquid crystal alignment solidification layer 2 is greater than or equal to the width of the adhesive layer 3. With such a configuration, the size (especially the width) of the optical laminate manufactured using the laminated film (see Figure 5) can be increased. The dimensions (typically the width) of the orientation solidified liquid crystal compound layer 2 in the orthogonal direction are, for example, 1.000 to 1.050 times, preferably 1.005 to 1.030 times, the dimensions (typically the width) of the adhesive layer 3 in the orthogonal direction. The width range of the first liquid crystal alignment solidification layer 2 is, for example, the same as the width range of the substrate layer 1 described above.

[0023] The average refractive index of the liquid crystal alignment solidification layer 2 at a wavelength of 550 nm is, for example, 1.45 to 1.65, preferably 1.50 to 1.65, and more preferably 1.55 to 1.65.

[0024] B-3.Adhesive layer In one embodiment, the adhesive layer 3 is provided on the surface of the first liquid crystal alignment solidification layer 2 opposite to the substrate layer 1. The adhesive layer 3 typically contains an adhesive. Examples of adhesives include (meth)acrylic adhesives, urethane adhesives, and silicone adhesives. These adhesives can be used individually or in combination. Among adhesives, (meth)acrylic adhesives are preferred.

[0025] (Meth)acrylic adhesives contain polymers of monomer components mainly composed of alkyl (meth)acrylate (hereinafter referred to as (meth)acrylic polymers). In other words, (meth)acrylic polymers contain structural units derived from alkyl (meth)acrylate. The content of structural units derived from alkyl (meth)acrylate is typically 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and for example, 100% by mass or less, preferably 98% by mass or less, in (meth)acrylic polymers.

[0026] The alkyl group in alkyl (meth)acrylate may be linear or branched. The number of carbon atoms in the alkyl group is, for example, 1 to 18. Examples of alkyl groups include methyl, ethyl, butyl, 2-ethylhexyl, decyl, isodecyl, and octadecyl groups. Alkyl (meth)acrylate can be used alone or in combination. The average number of carbon atoms in the alkyl group is preferably 3 to 10.

[0027] (Meth)acrylic polymers may contain structural units derived from alkyl (meth)acrylates, as well as structural units derived from copolymer monomers that can polymerize with alkyl (meth)acrylates. Examples of copolymer monomers include carboxyl group-containing monomers, hydroxyl group-containing monomers, amino group-containing monomers, and amide group-containing monomers. Copolymer monomers can be used alone or in combination. In one embodiment, the (meth)acrylic polymer contains structural units derived from alkyl (meth)acrylates, as well as structural units derived from carboxyl group-containing monomers, structural units derived from hydroxyl group-containing monomers, and structural units derived from amide group-containing monomers.

[0028] Carboxyl group-containing monomers are compounds that contain a carboxyl group in their structure and also contain polymerizable unsaturated double bonds such as (meth)acryloyl groups and vinyl groups. Examples of carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, maleic acid, fumaric acid, and crotonic acid, with (meth)acrylic acid being preferred. When a (meth)acrylic polymer contains structural units derived from carboxyl group-containing monomers, the adhesive properties of the adhesive layer can be improved. When the (meth)acrylic polymer contains structural units derived from carboxyl group-containing monomers, the content of structural units derived from carboxyl group-containing monomers is preferably 0.01% by mass or more and 10% by mass or less.

[0029] Hydroxyl group-containing monomers are compounds that contain a hydroxyl group in their structure and also contain polymerizable unsaturated double bonds such as (meth)acryloyl groups and vinyl groups. Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methyl acrylate. Preferably, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are used, and more preferably, 2-hydroxyethyl (meth)acrylate is used. When a (meth)acrylic polymer contains structural units derived from a hydroxyl group-containing monomer, the durability of the adhesive layer can be improved. When a (meth)acrylic polymer contains structural units derived from hydroxyl group-containing monomers, the content of structural units derived from hydroxyl group-containing monomers is preferably 0.01% by mass or more and 10% by mass or less in the (meth)acrylic polymer.

[0030] Amide group-containing monomers are compounds that contain an amide group in their structure and also contain polymerizable unsaturated double bonds such as (meth)acryloyl groups and vinyl groups. Examples of amide group-containing monomers include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylol-N-propane(meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, and mercaptomethyl Examples include acrylamide monomers such as (meth)acrylamide and mercaptoethyl(meth)acrylamide; N-acryloyl heterocyclic monomers such as N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, and N-(meth)acryloylpyrrolidine; and N-vinyl group-containing lactam monomers such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam. Preferably, N-acryloyl heterocyclic monomers are included, and more preferably, N-(meth)acryloylmorpholine. When the (meth)acrylic polymer contains structural units derived from amide group-containing monomers, the durability of the adhesive layer can be improved. When a (meth)acrylic polymer contains structural units derived from amide group-containing monomers, the content of structural units derived from amide group-containing monomers is preferably 1% by mass or more and 10% by mass or less, and more preferably 4% by mass or more and 8% by mass or less, in the (meth)acrylic polymer.

[0031] The weight-average molecular weight Mw of the (meth)acrylic polymer is, for example, 100,000 to 4,000,000, and preferably 200,000 to 3,000,000.

[0032] Furthermore, (meth)acrylic adhesives preferably contain a crosslinking agent. Typical examples of crosslinking agents include organic crosslinking agents and polyfunctional metal chelates, with organic crosslinking agents being preferred. Examples of organic crosslinking agents include isocyanate-based crosslinking agents, peroxide-based crosslinking agents, epoxy-based crosslinking agents, and imine-based crosslinking agents, with isocyanate-based crosslinking agents being preferred. When the adhesive contains a crosslinking agent, the proportion of the crosslinking agent is usually between 0.01 parts by mass and 15 parts by mass per 100 parts by mass of the (meth)acrylic polymer. Furthermore, the (meth)acrylic adhesive may contain various additives (e.g., polymerization initiators, solvents, crosslinking catalysts) in appropriate proportions.

[0033] Such adhesive compositions ((meth)acrylic adhesives, urethane adhesives, and silicone adhesives) contain a base polymer (or its constituent monomer components), and optionally a crosslinking agent and a solvent. The adhesive composition may also contain additives such as polymerization catalysts, crosslinking catalysts, silane coupling agents, tackifiers, plasticizers, softeners, degradation inhibitors, fillers, colorants, UV absorbers, antioxidants, surfactants, and antistatic agents, to the extent that they do not impair the properties of the present invention.

[0034] The thickness of the adhesive layer 3 is, for example, 3 μm or more, preferably 5 μm or more, and preferably 20 μm or more. On the other hand, the thickness of the adhesive layer 3 is, for example, 50 μm or less, and preferably 30 μm or less.

[0035] In one embodiment, the width of the adhesive layer 3 is less than or equal to the width of the first liquid crystal alignment solidification layer 2. In the illustrated example, the width of the adhesive layer 3 is smaller than the width of the first liquid crystal alignment solidification layer 2. Viewed from the thickness direction, the widthwise center of the adhesive layer 3 substantially coincides with the widthwise center of the first liquid crystal alignment solidification layer 2. The distance between the widthwise center of the adhesive layer 3 and the widthwise center of the first liquid crystal alignment solidification layer 2 is, for example, 10 mm or less, preferably 5 mm or less, and more preferably 0 mm. The width of the adhesive layer 3 is, for example, 1250 mm to 1350 mm, preferably 950 mm to 1450 mm.

[0036] The average refractive index of the adhesive layer 3 at a wavelength of 550 nm is typically smaller than the average refractive index of the first liquid crystal alignment solidification layer 2 at a wavelength of 550 nm. The absolute value of the difference between the average refractive index of the adhesive layer 3 and the average refractive index of the first liquid crystal alignment solidification layer 2 is, for example, 0.01 to 0.30, or for example, 0.05 to 0.20, or for example, 0.10 to 0.14. Even if the difference in average refractive index between the adhesive layer and the liquid crystal alignment solidification layer is within this range, since the relatively flat second surface of the adhesive layer is adjacent to the first liquid crystal alignment solidification layer, light interference can be stably reduced in an image display device to which the laminated film is applied. The average refractive index of the adhesive layer 3 at a wavelength of 550 nm is, for example, 1.30 to 1.70, preferably 1.42 to 1.52.

[0037] B-4. Peel-off liner The release liner 4 is positioned on the side opposite to the first liquid crystal alignment solidification layer 2 with respect to the adhesive layer 3. Typically, the release liner 4 is temporarily attached to the first surface 3a of the adhesive layer 3 until the laminated film 100 is used. The peel-off liner 4 contains any suitable resin material. Examples of the resin material include the resin material contained in the base layer 1, and preferably polyethylene terephthalate (PET), polyethylene, and polypropylene. Resin materials can be used alone or in combination.

[0038] In one embodiment, a release treatment layer is provided on the contact surface of the release liner 4 with the adhesive layer 3. The release layer typically contains a release agent. Examples of release agents include silicone-based release agents, fluorine-based release agents, and long-chain alkyl acrylate-based release agents, with silicone-based release agents being preferred, and vinyl group-containing addition-type silicones being even more preferred. Release agents can be used alone or in combination. The thickness of the release layer is, for example, 50 nm to 400 nm.

[0039] The arithmetic mean roughness (Ra) of the contact surface between the release liner 4 and the adhesive layer 3 is, for example, 5 nm to 40 nm, preferably 5 nm to 20 nm. The arithmetic mean roughness (Ra) is measured, for example, in accordance with JIS B0681-2:2018.

[0040] The thickness of the release liner 4 is, for example, 5 μm or more, preferably 20 μm or more. On the other hand, the thickness of the release liner 4 is, for example, 85 μm or less, preferably 45 μm or less. If a release treatment layer is applied, the thickness of the release liner includes the thickness of the release treatment layer.

[0041] C. Manufacturing method of laminated film Next, a method for manufacturing a laminated film according to one embodiment will be described with reference to Figures 2 and 3. In one embodiment, the method for manufacturing a laminated film comprises a first preparation step, a second preparation step, and a first lamination step. Compared to conventional methods for manufacturing laminated films, this method can reduce the number of steps and enable the smooth production of laminated films.

[0042] C-1.First preparation process As shown in Figure 2, in the first preparation step, the first liquid crystal alignment solidification layer 2 described above is formed on the surface of the substrate layer 1 in the thickness direction. In one embodiment, a substrate layer 1 is prepared, on one side in the thickness direction, which has been subjected to the orientation treatment described above. A coating liquid containing the liquid crystal compound is also prepared, and the coating liquid is applied to the orientation-treated surface of the substrate layer 1. This orients the liquid crystal compound in the direction corresponding to the orientation treatment. Subsequently, the orientation state of the liquid crystal compound is fixed by a method appropriate to the liquid crystal compound. As a result, a first liquid crystal alignment solidification layer 2 is formed on the surface of the substrate layer 1, and the first film 5 is prepared. The first film 5 may be in the form of a single sheet or in the form of a long strip. In one embodiment, the first film 5 is in the form of a long strip.

[0043] C-2.Second preparation process In the second preparation step, the adhesive layer 3 described above is formed on the surface of the peel-off liner 4 in the thickness direction. In one embodiment, a release liner 4 is prepared, which has the above-described release treatment layer on one side in the thickness direction. Next, the above-described adhesive is applied to the surface of the release treatment layer of the release liner 4 by any suitable method. After that, the coating is dried as necessary. This forms an adhesive layer 3 on the surface of the release liner 4, and the second film 6 is prepared. The second film 6 may be in the form of a single sheet or in the form of a long strip. In one embodiment, the second film 6 is in the form of a long strip. In the illustrated example, both the first film 5 and the second film 6 are in the form of a long strip.

[0044] The adhesive layer 3 of the second film 6 has, in the thickness direction, a first surface 3a on the side of the release liner 4 and a second surface 3b located away from the first surface 3a. In the second film 6, the second surface 3b of the adhesive layer 3 is an air surface and is exposed.

[0045] In the second film 6 according to one embodiment, the arithmetic mean roughness Ra of the second surface 3b of the adhesive layer 3 is smaller than the arithmetic mean roughness Ra of the first surface 3a of the adhesive layer 3. The arithmetic mean roughness Ra of the second surface 3b of the adhesive layer 3 is, for example, 0.6 times or less, preferably 0.4 times or less, and more preferably 0.2 times or less, compared to the arithmetic mean roughness Ra of the first surface 3a of the adhesive layer 3. On the other hand, the arithmetic mean roughness Ra of the second surface 3b of the adhesive layer 3 is, for example, 0.01 times or more, and also, for example, 0.5 times or more, compared to the arithmetic mean roughness Ra of the first surface 3a of the adhesive layer 3. The arithmetic mean roughness Ra of the first surface 3a of the adhesive layer 3 is, for example, 0 μm, or for example, 0.02 μm or more, or for example, 0.04 μm or more. On the other hand, the arithmetic mean roughness Ra of the first surface 3a of the adhesive layer 3 is, for example, 0.10 μm or less, preferably 0.08 μm or less, and more preferably 0.06 μm or less. The arithmetic mean roughness Ra of the second surface 3b of the adhesive layer 3 is, for example, less than 0.06 μm, preferably less than 0.04 μm, and more preferably 0.02 μm or less. On the other hand, the lower limit of the arithmetic mean roughness Ra of the second surface 3b of the adhesive layer 3 is typically 0 μm. If the arithmetic mean roughness of the second surface of the adhesive layer in the second film is within this range, the smoothness of the second surface of the adhesive layer in the manufactured laminated film can be improved, and as a result, minute defects (typically spot unevenness) in the image display device to which the laminated film is applied can be reduced more stably.

[0046] C-3.First lamination process As shown in Figure 3, in the first lamination step, the first film 5 and the second film 6 are laminated together. In one embodiment, the elongated first film 5 and the elongated second film 6 are laminated together such that their longitudinal directions are substantially parallel and their widthwise centers substantially coincide when viewed from the thickness direction. More specifically, the adhesive layer 3 of the second film 6 is brought into contact with the first liquid crystal alignment solidification layer 2 of the first film 5. As a result, the second surface 3b of the adhesive layer 3 is adjacent to the first liquid crystal alignment solidification layer 2. As described above, a laminated film 100 is manufactured comprising a base layer 1, a first liquid crystal alignment solidification layer 2, an adhesive layer 3, and a release liner 4 in this order.

[0047] C-4.Cutting process The method for manufacturing the laminated film may further include a cutting step, if necessary. In the cutting process, both ends of the laminated film 100 in a direction perpendicular to the lamination direction of the laminated film 100 are cut by any suitable method. In one embodiment, while the laminated film 100 is conveyed in the longitudinal direction, both ends of the laminated film 100 in the width direction are continuously cut along the longitudinal direction. This allows for proper adjustment of the dimensions (especially the width) of the laminated film. Including a cutting process facilitates the peeling of the substrate layer 1 from the laminated film 100. As shown in Figure 4, in the laminated film 100 after the cutting process, the widths of the base layer 1, the first liquid crystal alignment solidification layer 2, the adhesive layer 3, and the release liner 4 are substantially the same.

[0048] D. Method for manufacturing optical laminates Such laminated films 100 are typically used in optical laminates 101 applicable to image display devices. Next, a method for manufacturing an optical laminate according to one embodiment will be described with reference to Figures 4 and 5. In one embodiment, the method for manufacturing an optical laminate includes a first peeling step, a second bonding step, and a second peeling step.

[0049] D-1. First peeling process In the method for manufacturing an optical laminate, first, the laminated film 100 is manufactured by the method for manufacturing a laminated film as described above. Subsequently, as shown in Figure 4, in the first peeling step, the peeling liner 4 provided on the laminated film 100 is peeled off from the adhesive layer 3. This exposes the first surface 3a of the adhesive layer 3.

[0050] D-2.Second lamination process Next, as shown in Figure 5, in the second bonding step, the optical film 7 is attached to the first surface 3a of the adhesive layer 3 from which the release liner 4 has been peeled off.

[0051] D-2-1. Optical Film The optical film 7 may be in the form of a single sheet or in the form of a long strip. In one embodiment, the optical film 7 is in the form of a long strip. In one embodiment, the width of the optical film 7 is greater than or equal to the width of the adhesive layer 3. The width of the optical film 7 is, for example, 1.000 to 1.030 times, preferably 1.005 to 1.010 times, the width of the adhesive layer 3. When the width of the optical film is within this range relative to the width of the adhesive layer, an optical laminate with a wider effective width can be manufactured.

[0052] The optical film 7 has any suitable optical properties. The optical film 7 may have a single-layer structure or a laminated structure. Examples of optical films 7 include polarizing plates, phase difference films, polarizing plate protective films, phase difference protective films, image display device protective films, ultraviolet light transmission suppression films, and infrared light transmission suppression films. Optical films 7 may contain these individually or in combination of two or more types.

[0053] As shown in Figure 6, in one embodiment, the optical film 7 comprises a polarizing plate 7a and a phase difference film 7b.

[0054] A polarizing plate 7a typically includes a polarizer 71. Any suitable polarizer can be used as the polarizer 71. The polarizer may be composed of, for example, a single layer of resin film, or it may be obtained using a laminate of two or more layers.

[0055] Specific examples of polarizers composed of a single layer of resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) resin films, partially formalized PVA resin films, and partially saponified ethylene-vinyl acetate copolymer films, which have been subjected to dyeing and stretching treatments with dichroic substances such as iodine or dichroic dyes, as well as polyene-based oriented films such as dehydrated PVA or dehydrochlorinated polyvinyl chloride. Preferably, polarizers obtained by dyeing a PVA resin film with iodine and uniaxially stretching are used because they have excellent optical properties.

[0056] Specific examples of polarizers obtained using laminates include polarizers obtained using a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or polarizers obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. Polarizers obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate can be produced, for example, by applying a PVA-based resin solution to a resin substrate, drying it to form a PVA-based resin layer on the resin substrate, and obtaining a laminate of the resin substrate and the PVA-based resin layer; or by stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. In one embodiment, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, stretching may further include, if necessary, air-stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. In addition, in one embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which it shrinks by 2% or more in the width direction by heating while being transported in the longitudinal direction. Typically, the manufacturing method of this embodiment includes applying an air-assisted stretching treatment, a dyeing treatment, a water-based stretching treatment, and a drying shrinkage treatment to the laminate in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of PVA even when PVA is coated on a thermoplastic resin, making it possible to achieve high optical properties. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as a decrease in the orientation of PVA and dissolution when immersed in water in the subsequent dyeing and stretching processes, making it possible to achieve high optical properties. Furthermore, when the PVA-based resin layer is immersed in liquid, the disorder of the orientation of polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain halides. This makes it possible to improve the optical properties of polarizers obtained through processing steps that involve immersing the laminate in liquid, such as dyeing and water-based stretching treatments. Furthermore, by shrinking the laminate in the width direction through the drying shrinkage treatment, the optical properties can be improved.The resulting resin substrate / polarizer laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled off from the resin substrate / polarizer laminate, and any appropriate protective layer may be laminated onto the peeled surface according to the purpose. Details of such polarizer manufacturing methods are described, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0057] The above-mentioned iodine dyeing is carried out, for example, by immersing the PVA resin film in an iodine aqueous solution. The stretching ratio for the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment, or during the dyeing process. Alternatively, dyeing may be performed after stretching. If necessary, the PVA resin film may be subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc. For example, by immersing the PVA resin film in water and washing it before dyeing, not only can dirt and blocking inhibitors on the surface of the PVA resin film be washed away, but the PVA resin film can also be swollen to suppress uneven dyeing.

[0058] The thickness of the polarizer 71 is, for example, 1 μm to 80 μm, preferably 1 μm to 15 μm, more preferably 1 μm to 12 μm, and even more preferably 3 μm to 8 μm.

[0059] The polarizer 71 typically exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The transmittance of the polarizer 71 is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, and more preferably 44.5% to 46.0%. The degree of polarization of the polarizer 71 is preferably 97.0% or higher, more preferably 99.0% or higher, and even more preferably 99.9% or higher.

[0060] The polarizing plate 7a may include a protective layer 72 in addition to the polarizer 71. The protective layer 72 is provided on at least one side of the polarizer 71. That is, the protective layer 72 may be provided on only one side of the polarizer 71, or on both sides of the polarizer 71. In the illustrated example, the protective layer 72 is provided on only one side of the polarizer 71. Typically, the protective layer 72 is attached to the polarizer 71 via any suitable adhesive layer (not shown).

[0061] The protective layer is formed from any suitable film that can be used as a protective layer for the polarizer. Typical materials that make up the main component of the film include transparent resins, specifically, cycloolefin (COP) resins such as polynorbornene; polyester resins such as polyethylene terephthalate (PET); cellulose resins such as triacetylcellulose (TAC); polycarbonate (PC) resins; (meth)acrylic resins; polyvinyl alcohol resins; polyamide resins; polyimide resins; polyethersulfone resins; polysulfone resins; polystyrene resins; polyolefin resins; and acetate resins. Thermosetting resins or UV-curing resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone resins can also be used. In addition, glassy polymers such as siloxane polymers can also be used. Polymer films described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As materials for this film, for example, a resin composition containing a thermoplastic resin having substituted or unsubstituted imide groups in its side chains, and a thermoplastic resin having substituted or unsubstituted phenyl groups and nitrile groups in its side chains may be used. Examples include a resin composition having an alternating copolymer of isobutene and N-methylmaleimide, and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extruded product of the above resin composition. The materials for the resin film may be used individually or in combination.

[0062] The thickness of the protective layer 72 is, for example, 5 mm or less, preferably 1 mm or less, more preferably 1 μm to 500 μm, and even more preferably 5 μm to 150 μm.

[0063] Furthermore, a surface treatment layer may be provided on the surface of the protective layer 72 as needed. Examples of surface treatment layers include a hard coat layer, an anti-reflective layer, an anti-sticking layer, and an anti-glare treatment layer.

[0064] The thickness of such a polarizing plate 7a is, for example, 25 μm to 150 μm, preferably 30 μm to 70 μm.

[0065] The phase difference film 7b may have an in-plane phase difference, or it may have a phase difference in the thickness direction. The phase difference film 7b preferably has an in-plane phase difference. The refractive index of the phase difference film 7b satisfies, for example, the relationship nx > ny = nz. The in-plane phase difference Re(550) of the phase difference film 7b is, for example, 100 nm to 300 nm. The Nz coefficient of the phase difference film 7b is, for example, 0.9 to 1.5, preferably 0.9 to 1.3.

[0066] The phase difference film 7b may function as a λ / 2 plate, or as a λ / 3 plate, λ / 4 plate, λ / 5 plate, or C-Plate. In the illustrated example, the phase difference film 7b functions as a λ / 2 plate. When the phase difference film 7b functions as a λ / 2 plate, the in-plane phase difference Re(550) of the phase difference film 7b is preferably 200nm to 300nm, more preferably 230nm to 290nm, and even more preferably 250nm to 280nm. In other words, in one embodiment, the first liquid crystal alignment solidification layer 2 functions as a λ / 4 plate, and the phase difference film 7b functions as a λ / 2 plate. With such a configuration, the wavelength dispersion characteristics of the manufactured optical laminate can be brought closer to ideal inverse wavelength dispersion characteristics. Therefore, excellent anti-reflective properties can be imparted to the optical laminate. Furthermore, the phase difference film 7b may function as a λ / 4 plate, and the first liquid crystal alignment solidification layer 2 may function as a λ / 2 plate. In the optical film 7, the angle between the absorption axis direction of the polarizer 71 and the slow phase axis direction of the phase difference film 7b is, for example, 10° to 20°, preferably 12° to 18°, and more preferably 14° to 16°.

[0067] In one embodiment, the phase difference film 7b includes an orientation solidification layer of a liquid crystal compound. Hereinafter, the orientation solidification layer of the liquid crystal compound in the phase difference film 7b may be referred to as the second liquid crystal orientation solidification layer 74. The second liquid crystal alignment solidification layer 74 will be described in the same manner as the first liquid crystal alignment solidification layer 2. Therefore, a detailed description of the second liquid crystal alignment solidification layer 74 will be omitted. When the optical laminate 101 includes a second liquid crystal alignment solidification layer 74 and a first liquid crystal alignment solidification layer 2, spot unevenness is likely to occur at the interface between the liquid crystal alignment solidification layer, which has a larger refractive index difference with the adhesive, and the adhesive. When the optical laminate 101 is a polarizer plate including a polarizer 71, spot unevenness is likely to occur at the interface between the liquid crystal alignment solidification layer, which has a larger refractive index difference in the direction of the polarizer's transmission axis, and the adhesive. For this reason, it is preferable to bond the second surface 3b of the adhesive layer 3, which has a small arithmetic mean roughness Ra, to the liquid crystal alignment solidification layer, which has a larger refractive index difference with the adhesive. In the following, for convenience, the transmission axis direction of the polarizer (the direction perpendicular to the absorption axis direction) may be simply referred to as the transmission axis direction. When the optical laminate 101 is a polarizer plate containing a polarizer 71, the refractive index of the first liquid crystal alignment solidification layer 2 in the transmission axis direction is, for example, 1.50 or more, preferably 1.55 or more, more preferably exceeding 1.55, even more preferably exceeding 1.60, and particularly preferably 1.61 or more. On the other hand, the upper limit of the refractive index of the first liquid crystal alignment solidification layer 2 in the transmission axis direction is typically 1.70. Furthermore, the refractive index in the transmission axis direction of the second liquid crystal alignment solidification layer is typically smaller than that of the first liquid crystal alignment solidification layer 2 in the transmission axis direction. The refractive index of the second liquid crystal alignment solidification layer 74 in the transmission axis direction is, for example, 1.40 or higher, preferably 1.50 or higher. On the other hand, the refractive index of the second liquid crystal alignment solidification layer 74 in the transmission axis direction is, for example, 1.60 or lower, preferably less than 1.55.

[0068] In the illustrated example, the optical film 7 further comprises an adhesive layer 73. The adhesive layer 73 bonds the polarizing plate 7a and the phase difference film 7b. In the illustrated example, the adhesive layer 73 is located between the polarizer 71 of the polarizing plate 7a and the second liquid crystal alignment solidification layer 74 of the phase difference film 7b. The adhesive layer 73 contains any suitable adhesive. Examples of adhesives include thermosetting adhesives, moisture-curing adhesives, and active energy ray-curing adhesives, with active energy ray-curing adhesives being preferred. These adhesives can be used individually or in combination. The thickness of the adhesive layer 73 is, for example, 1 μm to 10 μm.

[0069] As shown in Figure 5, in one embodiment, an elongated optical film 7 and an elongated laminated film 100 are bonded together such that their longitudinal directions are substantially parallel and their centers in the width direction substantially coincide when viewed from the thickness direction. More specifically, the phase difference film 7b (see Figure 6) of the optical film 7 is brought into contact with the first surface 3a of the adhesive layer 3. This causes the optical film 7 to be attached to the first surface 3a of the adhesive layer 3.

[0070] As described above, an optical laminate 101 is manufactured comprising a base layer 1, a first liquid crystal alignment solidification layer 2, an adhesive layer 3, and an optical film 7 in this order. Subsequently, if necessary, the substrate layer 1 is peeled off from the first liquid crystal alignment solidification layer 2 (second peeling step). When the optical film 7 comprises a polarizer 71 and a second liquid crystal alignment solidification layer 74 (see Figure 6), in the optical laminate 101, the angle between the absorption axis direction of the polarizer 71 and the slow phase axis direction of the first liquid crystal alignment solidification layer 2 is, for example, 70° to 80°, preferably 72° to 78°, and more preferably 74° to 76°. With this configuration, the wavelength dispersion characteristics of the optical laminate comprising the first liquid crystal alignment solidification layer and the second liquid crystal alignment solidification layer can be brought closer to ideal inverse wavelength dispersion characteristics. Therefore, excellent anti-reflective properties can be stably imparted to the optical laminate. Furthermore, the range of angles between the absorption axis direction of the polarizer and the slow axis direction of the first liquid crystal alignment solidification layer may be reversed from the range of angles between the absorption axis direction of the polarizer and the slow axis direction of the second liquid crystal alignment solidification layer.

[0071] Each of the laminated films and optical laminates described above can be applied to any suitable image display device. Examples of image display devices include liquid crystal displays and organic EL displays. Typically, an image display device comprises an image display panel including an image display cell and the optical laminate described above. In one embodiment, the optical laminate is applied to an image display device to impart anti-reflective properties to the image display device. In other words, the optical laminate is suitably used as an anti-reflective optical laminate. Furthermore, an optical laminate including a polarizer can be suitably applied to an organic EL display device as a polarizing plate for OLEDs. [Examples]

[0072] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measurement methods for each characteristic are as follows.

[0073] (1) Arithmetic mean roughness Ra on the surface of the adhesive layer The surface of the adhesive layer in the examples and comparative examples was measured using a white light interferometer (Zygo NewView9000, manufactured by Zygo) under the following conditions, and two-dimensional images were obtained. Subsequently, the arithmetic mean roughness Ra of the adhesive layer surface was calculated by analyzing the two-dimensional images. White light interferometer measurement conditions: Objective lens; ×10 Internal lens; ×1.0 Resolution; 1.09μm Measurement field of view area (S); 0.3641mm 2 Removed Cylinder

[0074] [Example 1] <<First preparation process>> A liquid crystal composition (coating solution) was prepared by dissolving 10 parts by mass of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (BASF: trade name "Paliocolor LC242", represented by the following formula) and 3 parts by mass of a photopolymerization initiator for the polymerizable liquid crystal compound (BASF: trade name "Irgacure 907") in 40 parts by mass of toluene. [ka] The surface of a long polyethylene terephthalate (PET) film (base layer, 38 μm thick) was rubbed using a rubbing cloth and subjected to orientation treatment. The direction of the orientation treatment was set so that when laminated to an optical film (described later), it would be 75° from the viewing side relative to the absorption axis of the polarizer. The liquid crystal coating solution was applied to this orientation-treated surface using a bar coater, and the liquid crystal compound was oriented by heating and drying at 90°C for 2 minutes. In the liquid crystal layer formed in this manner, a metal halide lamp is used to apply 1 mJ / cm³ of liquid crystal. 2 A first liquid crystal alignment solidification layer was formed on the PET film by irradiating it with light and curing the liquid crystal layer. The thickness of the first liquid crystal alignment solidification layer was 1 μm. The first liquid crystal alignment solidification layer had a refractive index of nx > ny = nz. The in-plane phase difference Re(550) of the first liquid crystal alignment solidification layer was 140 nm. That is, the first optical film can function as a λ / 4 plate. The average refractive index of the first liquid crystal alignment solidification layer was 1.59, and the refractive index of the first liquid crystal alignment solidification layer in the transmission axis direction was 1.65. This resulted in the preparation of a first film comprising a first liquid crystal alignment solidification layer and a PET film (substrate layer). The first film was elongated in shape. The width of the first film was 1310 mm.

[0075] <<Second preparation process>> A 38 μm thick polyethylene terephthalate (PET) film (MRF38, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.), which has a silicone treatment on its release surface, was used as the release liner.

[0076] A monomer mixture containing 91 parts by mass of butyl acrylate, 6 parts by mass of acryloyl morpholine, 2.7 parts by mass of acrylic acid, and 0.3 parts by mass of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser. Furthermore, 0.1 parts by mass of 2,2'-azobisisobutyronitrile was added to 100 parts by mass of this monomer mixture as a polymerization initiator along with 100 parts by mass of ethyl acetate. After introducing nitrogen gas and purging the mixture with nitrogen while gently stirring, the polymerization reaction was carried out for 8 hours while maintaining the temperature of the liquid in the flask at around 55°C to prepare an acrylic polymer solution with a weight-average molecular weight (Mw) of 2.7 million. An adhesive composition was obtained by blending 0.1 parts by mass of an isocyanate crosslinking agent (trimethylolpropane / tolylene diisocyanate adduct: manufactured by Tosoh Corporation, trade name "Coronate L"), 0.3 parts by mass of a peroxide crosslinking agent (benzoyl peroxide: manufactured by Nippon Oil & Fats Co., Ltd., trade name "Nipper BMT"), and 0.2 parts by mass of an epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") with 100 parts by mass of solids of an acrylic polymer solution. The polymer concentration of the adhesive composition was adjusted to 8% by mass.

[0077] Next, an adhesive composition was applied to the silicone-treated surface of the release liner and then dried to form an adhesive layer. The thickness of the adhesive layer was 25 μm. The average refractive index of the adhesive layer was 1.47. The arithmetic mean roughness Ra of the first surface on the peel-off liner side of the adhesive layer was 0.05 μm. The arithmetic mean roughness Ra of the second surface (air surface) opposite the first surface of the adhesive layer was 0.01 μm. This resulted in the preparation of a second film comprising a release liner and an adhesive layer. The second film was elongated. The width of the adhesive layer in the second film was 1300 mm.

[0078] <<First lamination process>> Next, the first film and the second film were bonded together such that their longitudinal directions were substantially parallel and their widthwise centers substantially coincided when viewed from the thickness direction. More specifically, the first liquid crystal alignment solidification layer of the first film was brought into contact with the second surface of the adhesive layer of the second film, thereby bonding the first film and the second film together. This resulted in a laminated film comprising a base layer, a first liquid crystal alignment solidification layer, an adhesive layer, and a release liner in that order.

[0079] <<Cutting process>> Next, both ends of the laminated film in the width direction were cut. The width of the laminated film after cutting was 1290 mm.

[0080] <<First peeling process>> Next, the release liner of the laminated film was peeled off from the adhesive layer. This exposed the first surface of the adhesive layer.

[0081] <<Second lamination process>> First, the optical film was prepared as follows.

[0082] As a thermoplastic resin substrate, an amorphous isophthalic copolymer polyethylene terephthalate film (thickness: 100 μm) in a long length with a Tg of approximately 75°C was used, and one side of the resin substrate was subjected to corona treatment. A PVA aqueous solution (coating solution) was prepared by dissolving 100 parts by mass of a PVA-based resin, which was prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosephymer") in a 9:1 ratio, with 13 parts by mass of potassium iodide. A PVA aqueous solution was applied to the corona-treated surface of a resin substrate and dried at 60°C to form a 13 μm thick PVA-based resin layer, thereby creating a laminate. The resulting laminate was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) in an oven at 130°C (air-assisted stretching). Next, the laminate was immersed for 30 seconds in an insolubilization bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 4 parts by mass of boric acid with 100 parts by mass of water) (insolubilization treatment). Next, the polarizers were immersed for 60 seconds in a staining bath at a liquid temperature of 30°C (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by mass of water) while adjusting the concentration so that the final transmittance (Ts) of the polarizers obtained would be the desired value (staining treatment). Next, the material was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 3 parts by mass of potassium iodide and 5 parts by mass of boric acid with 100 parts by mass of water) (crosslinking treatment). Subsequently, the laminate was immersed in a boric acid aqueous solution (boric acid concentration 4% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70°C, and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to achieve a total stretch ratio of 5.5 times (underwater stretching treatment). Subsequently, the laminate was immersed in a washing bath at a liquid temperature of 20°C (an aqueous solution obtained by mixing 4 parts by mass of potassium iodide with 100 parts by mass of water) (washing treatment). Subsequently, the material was dried in an oven maintained at approximately 90°C while being brought into contact with a SUS (stainless steel) heated roll whose surface temperature was maintained at approximately 75°C (drying shrinkage treatment). In this way, a polarizer with a thickness of approximately 5 μm was formed on the resin substrate, and a laminate having a resin substrate / polarizer configuration was obtained. A norbornene resin film (25 μm thick) was bonded to the polarizer surface (the side opposite to the resin substrate) of the resulting laminate as a protective layer. Next, the resin substrate was peeled off from the polarizer. This allowed for the preparation of a polarizing plate comprising a protective layer and a polarizer. The polarizing plate was elongated in shape. The width of the polarizing plate was 1300 mm.

[0083] Furthermore, a second liquid crystal alignment solidification layer was formed on the PET film in the same manner as in the first preparation step, except that the coating thickness was changed and the orientation treatment direction was changed to a 15° direction relative to the absorption axis axis of the polarizer when viewed from the viewing side. The thickness of the second liquid crystal alignment solidification layer was 2 μm. The second liquid crystal alignment solidification layer had a refractive index of nx > ny = nz. The in-plane phase difference Re(550) of the second liquid crystal alignment solidification layer was 270 nm. In other words, the second liquid crystal alignment solidification layer can function as a λ / 2 plate. The average refractive index of the second liquid crystal alignment solidification layer was 1.59, and the refractive index in the transmission axis direction of the second liquid crystal alignment solidification layer was 1.54. As a result, a second phase difference film was prepared as a second optical film, comprising a second liquid crystal alignment solidification layer and a PET film (substrate layer). The second phase difference film was elongated. The width of the second phase difference film was 1300 mm.

[0084] Next, the polarizing plate and the second phase difference film were bonded together using an ultraviolet-curing adhesive such that their longitudinal directions were substantially parallel and their widthwise centers substantially coincided when viewed from the thickness direction. More specifically, an ultraviolet-curing adhesive was applied to the surface of the polarizer of the polarizing plate to form a coating. Next, the second liquid crystal alignment solidification layer of the second phase difference film was brought into contact with the coating from the side opposite to the first phase difference film. After that, the coating was irradiated with ultraviolet light to cure the ultraviolet-curing adhesive. This resulted in the preparation of an optical film comprising a polarizing plate, an adhesive layer, and a phase difference film in that order. The adhesive layer consisted of cured material from an ultraviolet-curing adhesive. The thickness of the adhesive layer was 1 μm. The width of the adhesive layer was 1295 mm. In the optical film, the angle between the absorption axis direction of the polarizing plate and the slow phase axis direction of the second liquid crystal alignment solidification layer was 15°.

[0085] Next, the laminated film and the optical film were bonded together such that their longitudinal directions were substantially parallel and their widthwise centers substantially coincided when viewed from the thickness direction. More specifically, first, the PET film (substrate layer) of the optical film was peeled off from the second liquid crystal alignment solidification layer. Then, the second liquid crystal alignment solidification layer of the optical film was brought into contact with the first surface of the adhesive layer of the laminated film, thereby bonding the laminated film and the optical film together. As a result, an optical laminate comprising a polarizing plate, an adhesive layer, a phase difference film (second liquid crystal alignment solidification layer), an adhesive layer, a first liquid crystal alignment solidification layer, and a substrate layer in this order was prepared. In the optical laminate, the angle between the absorption axis direction of the polarizer and the slow phase axis direction of the first liquid crystal alignment solidification layer was 75°. Subsequently, the substrate layer was peeled off and removed from the first liquid crystal alignment solidification layer (second peeling step).

[0086] [Comparative Example 1] The second film was prepared in the same manner as the second preparation step described above, except that the width of the adhesive layer was changed to 1290 mm. Next, the second film and the optical film described above were bonded together such that their longitudinal directions were substantially parallel and their widthwise centers substantially coincided when viewed from the thickness direction. More specifically, first, the substrate layer of the optical film was peeled off from the second liquid crystal alignment solidification layer. Then, the second liquid crystal alignment solidification layer of the optical film was brought into contact with the second surface of the adhesive layer of the second film, thereby bonding the second film and the optical film together. As a result, a laminate comprising a polarizing plate, an adhesive layer, a phase difference film (second liquid crystal alignment solidification layer), an adhesive layer, and a release liner in this order was prepared.

[0087] Furthermore, the first film was prepared in the same manner as the first preparation step described above. Subsequently, the prepared laminate and the first film were bonded together such that their longitudinal directions were substantially parallel and their widthwise centers substantially coincided when viewed from the thickness direction. More specifically, first, the release liner of the laminate was peeled off from the adhesive layer to expose the first surface of the adhesive layer. Then, the first liquid crystal alignment solidification layer of the first film was brought into contact with the first surface of the adhesive layer, thereby bonding the laminate and the first film together. As a result, an optical laminate comprising a polarizing plate, an adhesive layer, a phase difference film (second liquid crystal alignment solidification layer), an adhesive layer, a first liquid crystal alignment solidification layer, and a first substrate layer in this order was prepared. In the optical laminate, the angle between the absorption axis direction of the polarizer and the slow phase axis direction of the first liquid crystal alignment solidification layer was 75°. Next, both ends of the optical laminate in the width direction were cut. The width of the optical laminate after cutting was 1280 mm. Subsequently, the first substrate layer was peeled off and removed from the first liquid crystal alignment solidification layer (second peeling step).

[0088] [evaluation] An acrylic adhesive was placed on the surface of the first liquid crystal alignment solidification layer of the optical laminate obtained in Example 1 and Comparative Example 1, and the optical laminate was bonded to a V3 reflector (manufactured by NEODIS) via the acrylic adhesive to obtain a test sample. The length of the test sample was 5 m. The obtained test sample was observed visually under a three-wavelength fluorescent lamp. In the optical laminate of Example 1, the second surface of the relatively flat adhesive layer is adjacent to the first liquid crystal alignment solidification layer, so no spot unevenness was visible. On the other hand, in the optical laminate of Comparative Example 1, spot unevenness was visible because the first surface of the relatively rough adhesive layer was adjacent to the first liquid crystal alignment solidification layer. [Industrial applicability]

[0089] The laminated film according to the embodiment of the present invention can be suitably used in the manufacture of optical laminates applied to image display devices (typically liquid crystal display devices and organic EL display devices). [Explanation of Symbols]

[0090] 1 Base material layer 2. Liquid crystal alignment solidification layer 3. Adhesive layer 3a 1st page 3b 2nd side 4. Release Liner 5. Film 1 6. Film 2 7 Optical film

Claims

1. The material comprises a base layer, an orientation and solidification layer of a liquid crystal compound, an adhesive layer, and a release liner in this order. The release liner is attached to the surface of the adhesive layer in the thickness direction and is removable from the adhesive layer. The oriented solidified layer of the liquid crystal compound is arranged on the surface in the thickness direction of the substrate layer, The substrate layer is a laminated film that can be peeled off from the orientation solidification layer of the liquid crystal compound.

2. The laminated film according to claim 1, wherein in a direction perpendicular to the thickness direction, the dimensions of the orientation solidified layer of the liquid crystal compound are greater than or equal to the dimensions of the adhesive layer.

3. The laminated film according to claim 1 or 2, having an elongated shape.

4. The laminated film according to claim 1 or 2, wherein the orientation solidified layer of the liquid crystal compound has an in-plane phase difference.

5. The laminated film according to claim 1 or 2, wherein the adhesive layer comprises a (meth)acrylic adhesive.

6. The laminated film according to claim 1 or 2, wherein the substrate layer is a coating substrate for the orientation solidified layer of the liquid crystal compound.

7. A step to prepare a first film by forming an orientation solidified layer of liquid crystal compound on the surface in the thickness direction of the substrate layer, A step to prepare a second film by forming an adhesive layer on the surface of the release liner in the thickness direction, The process includes a step of bringing the adhesive layer of the second film into contact with the orientation solidification layer of the liquid crystal compound of the first film, thereby bonding the first film and the second film together. The substrate layer is peelable from the orientation solidification layer of the liquid crystal compound. A method for manufacturing laminated films.

8. The adhesive layer of the second film has, in the thickness direction, a first surface on the release liner side and a second surface located away from the first surface. The method for manufacturing a laminated film according to claim 7, wherein the arithmetic mean roughness Ra of the second surface of the adhesive layer is smaller than the arithmetic mean roughness Ra of the first surface of the adhesive layer.

9. The method for manufacturing a laminated film according to claim 7, further comprising the step of cutting both ends of the laminated film in a direction perpendicular to the lamination direction of the laminated film.

10. A step of manufacturing the laminated film by the method for manufacturing the laminated film described in any one of claims 7 to 9, The process of peeling the release liner provided in the laminated film from the adhesive layer, The process involves attaching an optical film to the surface of the adhesive layer from which the release liner has been peeled off, A method for manufacturing an optical laminate, further comprising the step of peeling the substrate layer from the orientation solidification layer of the liquid crystal compound.

11. The method for manufacturing an optical laminate according to claim 10, wherein the optical laminate includes a polarizer, and the orientation solidification layer of the liquid crystal compound has a refractive index in the transmission axis direction of the polarizer that exceeds 1.

55.

12. The method for manufacturing an optical laminate according to claim 11, wherein the optical film includes a polarizer, and the orientation solidification layer of the liquid crystal compound has a refractive index in the transmission axis direction of the polarizer that exceeds 1.60.

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