JPWO2014148261A1 - Optical laminate, polarizing plate composite, liquid crystal display device, and manufacturing method - Google Patents

Abstract

An optical laminate comprising a retardation layer P1 made of a resin p1 containing a polystyrene-based polymer having a polyphenylene ether and a syndiotactic structure, and a retardation layer P2 made of a resin p2 containing an alicyclic structure-containing polymer. In the resin p1, the weight ratio of the content of the polyphenylene ether / the content of the polystyrene polymer is larger than 25/75 and smaller than 35/65, and the NZ coefficient NZP1 of the retardation layer P1 is NZP1 <0, and the optical laminated body satisfies the relationship of 0.92 ≦ R40 / Re ≦ 1.08 in which the retardation Re at the incident angle of 0 ° and the retardation R40 at the incident angle of 40 ° of the optical laminated body satisfy the relationship of 0.92 ≦ R40 / Re ≦ 1.08. And a production method thereof, and a polarizing plate composite comprising the same.

Description

  The present invention relates to an optical laminate, a polarizing plate composite, a liquid crystal display device, a method for producing an optical laminate, and a method for producing a polarizing plate composite.

  In a display device such as a liquid crystal display device, for example, an optical layered body in which a plurality of retardation layers are combined may be used in combination with another member such as a polarizing plate in order to compensate for a viewing angle. As the retardation layer, a stretched film obtained by stretching a long unstretched film formed of a resin and orienting molecules contained in the film can be easily produced, and is preferable.

  Many studies have been made on stretched films for use as retardation layers. For example, techniques such as Patent Documents 1 to 4 are known. Among these, Patent Documents 1 to 3 describe a technique for producing a retardation film having reverse wavelength dispersion as a stretched film. Here, the reverse wavelength dispersibility means the property that the retardation in the in-plane direction given to the light increases as the wavelength of the light transmitted through the retardation film becomes longer.

International Publication No. 2010/074166 JP 2011-113004 A JP 2010-78905 A JP-A-7-266414

In recent years, in a display device such as a liquid crystal display device, there is an increasing demand for reducing the thickness of the device. For this reason, the retardation layer is also required to be thinner than before.
However, if a high phase difference is to be expressed in a thin film, it is necessary to increase the draw ratio. When the stretch ratio is increased, the variation in the alignment direction increases, and as a result, performance such as viewing angle compensation can be insufficient. Further, if the stretching ratio is simply increased in order to set the in-plane retardation Re to a desired value, the retardation Rth in the thickness direction does not become a desired value and the viewing angle compensation performance is often insufficient. Furthermore, in a conventional stretched film, the retardation may change greatly when used for a long time at a high temperature, and such a change can be particularly noticeable when the stretch ratio is increased.

  Accordingly, an object of the present invention is to provide an optical laminate that is thin, has high viewing angle compensation performance, and has excellent durability when used at high temperatures, a polarizing plate composite including the same, a liquid crystal display device, and a method for producing the same. It is to provide.

The present inventors have studied to solve the above-mentioned problems. As a result, the retardation layer P1 made of a resin p1 in which polyphenylene ether and a polystyrene-based polymer having a predetermined structure are combined at a predetermined weight ratio, and an alicyclic ring It has been found that such an optical laminate can be obtained by a combination with a retardation layer P2 made of a resin p2 containing a polymer having a formula structure. The present inventor further found that such an optical laminate can be easily produced by a predetermined method including a step of co-extrusion of a plurality of resins including the resin p1. The present invention has been completed based on such findings.
That is, the present invention is as follows.

[1] A retardation layer P1 made of a resin p1 containing a polyphenylene ether and a polystyrene polymer having a syndiotactic structure;
An optical laminate comprising a retardation layer P2 made of a resin p2 containing an alicyclic structure-containing polymer,
In the resin p1, the weight ratio of the content of the polyphenylene ether / the content of the polystyrene polymer is larger than 25/75 and smaller than 35/65.
NZ coefficient _{NZ P1} of the retardation layer P1 is a _{NZ P1} <0,
An optical laminate in which retardation Re at an incident angle of 0 ° and retardation R ₄₀ at an incident angle of 40 ° satisfy the relationship of 0.92 ≦ R ₄₀ /Re≦1.08.
[2] In-plane retardation Re (P1) and thickness direction retardation Rth (P1) of the retardation layer P1, and in-plane retardation Re (P2) and thickness direction retardation Rth (P2) of the retardation layer P2. ) Is the following formula (1) and formula (2):
Re (P1) + Re (P2) ≧ 100 nm Formula (1)
−50 nm ≦ Rth (P1) + Rth (P2) ≦ 50 nm Formula (2)
The optical laminate according to [1], wherein
[3] The optical layered body according to [1] or [2], wherein the retardation layer P1 has a thickness of 15 μm or less and a thickness direction retardation Rth (P1) of −50 nm or less.
[4] The polyphenylene ether has a weight average molecular weight of 15,000 to 100,000,
The optical laminated body according to any one of [1] to [3], wherein the polystyrene-based polymer has a weight average molecular weight of 130,000 to 300,000.
[5] In any one of [1] to [4], an intersection angle between the slow axis of the retardation layer P1 and the slow axis of the retardation layer P2 is 0 ° ± 10 °. The optical laminated body as described.
[6] A polarizing plate composite comprising the optical laminate according to any one of [1] to [5] and a polarizer.
[7] The polarizing plate composite according to [6], wherein the slow axis of the optical laminate and the absorption axis of the polarizer are orthogonal to each other.
[8] A liquid crystal display device comprising the polarizing plate composite according to [6] or [7] and a liquid crystal cell.
[9] An in-plane switching mode liquid crystal display device including an incident side polarizer, a liquid crystal cell, and an output side polarizer in this order,
The liquid crystal display device according to [5], further in a position between the incident-side polarizer and the liquid crystal cell, a position between the output-side polarizer and the liquid crystal cell, or both positions. With an optical laminate of
The optical layered body is an in-plane switching mode liquid crystal display device in which the retardation layer P1 is disposed on the liquid crystal cell side.
[10] The method for producing an optical laminate according to any one of [1] to [5],
A resin p1 comprising a polyphenylene ether and a polystyrene polymer having a syndiotactic structure, wherein a weight ratio of the content of the polyphenylene ether / the content of the polystyrene polymer is larger than 25/75 and smaller than 35/65; Coextruding the resin p3 containing a (meth) acrylic polymer to obtain a pre-stretching film PF (I);
Stretching the pre-stretched film PF (I) to obtain a stretched multilayer film F (I) including the retardation layer P1 made of the resin p1 and the protective layer P3 made of the resin p3;
Extruding the resin p2 containing the alicyclic structure-containing polymer to obtain a film PF (II) before stretching;
Stretching the pre-stretched film PF (II) to obtain a film F (II) of the retardation layer P2, and
The manufacturing method which has the process of bonding the said phase difference layer P1 and the said phase difference layer P2.
[11] The manufacturing method according to [10], further including a step of peeling the protective layer P3 from the retardation layer P1.
[12] The obtained optical layered body has a long shape including the retardation layer P1 having a long shape and the retardation layer P2 having a long shape,
The retardation layer P1 has a slow axis in its width direction,
The said retardation layer P2 is a manufacturing method as described in [10] or [11] which has a slow axis in the width direction.
[13] A method for producing a long polarizing plate composite, comprising a step of laminating a long optical laminate obtained by the production method according to [12] and a long polarizer by roll-to-roll. .

  The optical laminate of the present invention, the polarizing plate composite of the present invention including the optical laminate, and the liquid crystal display device of the present invention are thin, have high viewing angle compensation performance, and are excellent in durability at high temperatures. Moreover, in the manufacturing method of this invention, such an optical laminated body and polarizing plate composite of this invention can be manufactured easily.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention is not limited to the following embodiments and examples, and the claims of the present invention and equivalents thereof. The present invention may be carried out with any change without departing from the above range.
In the following description, the expression (meth) acryl means acryl, methacryl or a combination thereof. For example, (meth) acrylic acid means acrylic acid, methacrylic acid or a combination thereof. (Meth) acrylate means acrylate, methacrylate or a combination thereof.
In the following description, the MD direction (machine direction) is a film flow direction in the production line, and usually represents a direction that coincides with the longitudinal direction of a long film. Further, the TD direction (traverse direction) is a direction parallel to the film surface and perpendicular to the MD direction, and usually represents a direction that coincides with the width direction of a long film.
In the following description, unless otherwise specified, the measurement wavelength of refractive index and retardation is 550 nm. The slow axis of the film or layer represents the in-plane slow axis unless otherwise specified.
In the following description, the NZ coefficient represents (nx−nz) / (nx−ny). Here, nx represents the refractive index in the direction perpendicular to the thickness direction (in-plane direction) and gives the maximum refractive index, and ny is the direction perpendicular to the thickness direction (in-plane direction) and is in the nx direction. Represents the refractive index in the direction perpendicular to, and nz represents the refractive index in the thickness direction.

[1. Optical laminate]
The optical layered body of the present invention includes a retardation layer P1 made of a resin p1 and a retardation layer P2 made of a resin p2.

[1-1. Resin p1]
The resin p1 includes a polyphenylene ether and a polystyrene-based polymer having a syndiotactic structure. Polyphenylene ether usually has a positive intrinsic birefringence value, and a polystyrene-based polymer having a syndiotactic structure usually has a negative intrinsic birefringence value. Here, the intrinsic birefringence value being positive means that the refractive index in the stretching direction is larger than the refractive index in the direction perpendicular to the stretching direction. Further, the negative intrinsic birefringence value means that the refractive index in the stretching direction is smaller than the refractive index in the direction perpendicular to the stretching direction. The intrinsic birefringence value can also be calculated from the dielectric constant distribution.

  Polyphenylene ether is a polymer having a structural unit formed by polymerizing phenylene ether or a phenylene ether derivative. Usually, a polymer having a structural unit having a phenylene ether skeleton (hereinafter, appropriately referred to as “phenylene ether unit”) in the main chain is used as polyphenylene ether. However, the benzene ring in the phenylene ether unit may have a substituent unless the effects of the present invention are significantly impaired.

  Among these, as the polyphenylene ether, a polymer containing a phenylene ether unit represented by the following formula (I) is preferable.

In formula (I), each Q ¹ independently represents a halogen atom, a lower alkyl group (for example, an alkyl group having 7 or less carbon atoms), a phenyl group, a haloalkyl group, an aminoalkyl group, a hydrocarbonoxy group, or a halo. A hydrocarbon oxy group (wherein the halogen atom and the oxygen atom are separated by at least two carbon atoms). Among these, Q ¹ is preferably an alkyl group or a phenyl group, and more preferably an alkyl group having 1 to 4 carbon atoms.

In formula (I), each Q ² independently represents a hydrogen atom, a halogen atom, a lower alkyl group (for example, an alkyl group having 7 or less carbon atoms), a phenyl group, a haloalkyl group, a hydrocarbon oxy group, or a halocarbon. A hydrogenoxy group (however, a group in which at least two carbon atoms are separated from the halogen atom and the oxygen atom). Among them, preferably a hydrogen atom ^{Q 2.}

The polyphenylene ether may be a homopolymer having one type of structural unit or a copolymer having two or more types of structural units.
When the polymer containing the structural unit represented by the formula (I) is a homopolymer, preferred examples of the homopolymer include 2,6-dimethyl-1,4-phenylene ether units (“-( And a homopolymer having a structural unit represented by “C ₆ H ₂ (CH ₃ ) ₂ —O) —”.
When the polymer containing the structural unit represented by the formula (I) is a copolymer, preferred examples of the copolymer include 2,6-dimethyl-1,4-phenylene ether units and 2,3. , 6-trimethyl-1,4-phenylene ether unit (a structural unit represented by “— (C ₆ H (CH ₃ ) ₃ —O —) —”).

  The polyphenylene ether may contain a structural unit other than the phenylene ether unit. In this case, polyphenylene ether is a copolymer having phenylene ether units and other structural units. However, the content of structural units other than the phenylene ether unit in the polyphenylene ether is preferably reduced to such an extent that the effects of the present invention are not significantly impaired. Specifically, the content of the phenylene ether unit in the polyphenylene ether is usually 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more.

  A polyphenylene ether may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The weight average molecular weight of polyphenylene ether is usually 15,000 or more, preferably 25,000 or more, more preferably 35,000 or more, and usually 100,000 or less, preferably 85,000 or less, more preferably 70,000. It is as follows. By setting the weight average molecular weight to be equal to or higher than the lower limit of the above range, the strength of the retardation layer P1 can be increased. Moreover, by making it below the upper limit value, it becomes possible to improve the dispersibility of the polyphenylene ether and uniformly mix the polyphenylene ether and the styrene polymer at a high level.
Here, as the weight average molecular weight, a standard polystyrene conversion value measured by gel permeation chromatography (GPC) at a temperature of 135 ° C. using 1,2,4-trichlorobenzene as a solvent is adopted.

  There is no restriction | limiting in the manufacturing method of polyphenylene ether, For example, it can manufacture by the method as described in Unexamined-Japanese-Patent No. 11-302529.

The polystyrene-based polymer is a polymer including a structural unit (hereinafter referred to as “styrene unit” as appropriate) formed by polymerizing a styrene compound. Examples of styrene compounds include styrene and styrene derivatives. Examples of styrene derivatives include those in which a substituent is substituted at the benzene ring or α-position of styrene.
Examples of styrene compounds include styrene; alkyl styrene such as methyl styrene and 2,4-dimethyl styrene; halogenated styrene such as chlorostyrene; halogen-substituted alkyl styrene such as chloromethyl styrene; alkoxy styrene such as methoxy styrene; Etc. Among them, styrene having no substituent is preferable as the styrene compound. Moreover, a styrene compound may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  As the polystyrene polymer contained in the resin p1, a polymer having a syndiotactic structure is used. Here, the polystyrene polymer has a syndiotactic structure means that the stereochemical structure of the polystyrene polymer has a syndiotactic structure. The syndiotactic structure refers to a three-dimensional structure in which phenyl groups that are side chains are alternately positioned in opposite directions in the Fischer projection formula with respect to a main chain formed by carbon-carbon bonds.

The tacticity (stericity) of the polystyrene polymer can be quantified by an isotope carbon nuclear magnetic resonance method ( ¹³ C-NMR method). ^The tacticity measured by the ¹³ C-NMR method can be indicated by the existence ratio of a plurality of consecutive structural units. Generally, for example, when there are two consecutive structural units, it is a dyad, when it is three, it is a triad, and when it is five, it is a pentad. In this case, the polystyrene-based polymer having a syndiotactic structure usually has a syndiotacticity of 75% or more, preferably 85% or more in racemic dyad, or usually 30% or more in racemic pentad. It preferably means having a syndiotacticity of 50% or more. In any case, the upper limit of syndiotacticity can ideally be 100%.

Examples of polystyrene polymers include polystyrene, poly (alkyl styrene), poly (halogenated styrene), poly (halogenated alkyl styrene), poly (alkoxy styrene), poly (vinyl benzoate), and hydrogens thereof. And a copolymer thereof.
Examples of the poly (alkyl styrene) include poly (methyl styrene), poly (ethyl styrene), poly (isopropyl styrene), poly (t-butyl styrene), poly (phenyl styrene), poly (vinyl naphthalene), poly ( Vinyl styrene).
Examples of poly (halogenated styrene) include poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene), and the like.
Examples of poly (halogenated alkylstyrene) include poly (chloromethylstyrene).
Examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene).

  Among these, particularly preferred polystyrene polymers include polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (pt-butylstyrene), poly (p-chlorostyrene), poly ( m-chlorostyrene), poly (p-fluorostyrene), hydrogenated polystyrene, and copolymers containing these structural units.

  Further, the polystyrene polymer may be a homopolymer having only one type of structural unit or a copolymer having two or more types of structural units. When the polystyrene polymer is a copolymer, it may be a copolymer containing two or more types of styrene units, and it is a copolymer containing a styrene unit and a structural unit other than the styrene unit. There may be. However, when the polystyrene polymer is a copolymer containing a styrene unit and a structural unit other than the styrene unit, the content of the structural unit other than the styrene unit in the polystyrene polymer is the effect of the present invention. Is preferably reduced to such an extent that it is not significantly impaired. Specifically, the content of styrene units in the polystyrene-based polymer is usually 80% by weight or more, preferably 83% by weight or more, and more preferably 85% by weight or more. Usually, by setting the amount of styrene units within such a range, a desired retardation can be expressed in the produced retardation layer.

  A polystyrene type polymer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  The weight average molecular weight of the polystyrene polymer is usually 130,000 or more, preferably 140,000 or more, more preferably 150,000 or more, and usually 300,000 or less, preferably 270,000 or less, more preferably 250. , 000 or less. With such a weight average molecular weight, the glass transition temperature of the polystyrene polymer can be increased, and the heat resistance of the retardation layer can be stably improved.

  The glass transition temperature of the polystyrene-based polymer is usually 85 ° C. or higher, preferably 90 ° C. or higher, more preferably 95 ° C. or higher. Thus, by raising the glass transition temperature of a polystyrene-type polymer, the glass transition temperature of resin p1 can be raised effectively, and by extension, the heat resistance of a phase difference layer can be improved stably. Further, from the viewpoint of stably and easily producing the optical laminate, the glass transition temperature of the polystyrene-based polymer is usually 160 ° C. or lower, preferably 155 ° C. or lower, more preferably 150 ° C. or lower.

  A polystyrene polymer having a syndiotactic structure polymerizes a styrene compound using, for example, a titanium compound and a condensation product of water and trialkylaluminum as a catalyst in an inert hydrocarbon solvent or in the absence of a solvent. (See JP-A-62-187708). Poly (halogenated alkylstyrene) can be produced, for example, by the method described in JP-A-1-46912. Further, these hydrogenated polymers can be produced, for example, by the method described in JP-A-1-178505.

In the resin p1, the weight ratio of the polyphenylene ether content / polystyrene polymer content is larger than 25/75 and smaller than 35/65. The weight ratio of content of polyphenylene ether / polystyrene polymer is preferably 26/74 or more, more preferably 28/72 or more, preferably 34/66 or less, more preferably 32/68 or less. is there.
By setting the ratio of the polyphenylene ether and the polystyrene-based polymer within the above range, an optical laminate that is thin and has high viewing angle compensation performance can be obtained.

As long as the effects of the present invention are not significantly impaired, the resin p1 may contain components other than polyphenylene ether and polystyrene polymer.
For example, the resin p1 may contain a polymer other than the polyphenylene ether and the polystyrene-based polymer described above. The amount of the polymer other than polyphenylene ether and polystyrene polymer is preferably 15 parts by weight or less, more preferably 10 parts by weight or less, and more preferably 5 parts by weight or less, based on 100 parts by weight of the total amount of polyphenylene ether and polystyrene polymer. Is particularly preferred.

For example, resin p1 may contain the compounding agent. Examples of compounding agents are layered crystal compounds; fine particles; antioxidants, heat stabilizers, light stabilizers, weathering stabilizers, UV absorbers, near infrared absorbers and other stabilizers; plasticizers: dyes and pigments, etc. Colorants; antistatic agents; and the like. Moreover, a compounding agent may use one type and may use it combining two or more types by arbitrary ratios.
The amount of the compounding agent can be appropriately determined as long as the effects of the present invention are not significantly impaired. For example, it is a range in which the total light transmittance of the retardation layer can be maintained at 85% or more.

Among the above-mentioned, as the compounding agent, fine particles and ultraviolet absorbers are preferable in terms of improving flexibility and weather resistance.
As fine particles, for example, inorganic particles such as silicon dioxide, titanium dioxide, magnesium oxide, calcium carbonate, magnesium carbonate, barium sulfate, strontium sulfate; polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, cellulose acetate, cellulose acetate propionate Organic particles such as Among these, organic particles are preferable.

  Examples of ultraviolet absorbers include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, acrylonitrile ultraviolet absorbers, triazine compounds, nickel complex compounds. And inorganic powders. Examples of suitable UV absorbers include 2,2′-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2,4-di-tert-butyl-6- (5-chlorobenzotriazol-2-yl) phenol 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, and particularly preferred is 2,2′-methylenebis (4- ( 1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol.

  The glass transition temperature of the resin p1 is preferably 115 ° C. or higher, more preferably 118 ° C. or higher, and even more preferably 120 ° C. or higher. Since the resin p1 contains a combination of polyphenylene ether and polystyrene polymer, the glass transition temperature can be increased as compared with a resin containing only a polystyrene polymer. Since the glass transition temperature is thus high, the relaxation of the orientation of the resin p1 can be reduced, so that a retardation layer having excellent heat resistance can be realized. Moreover, although there is no restriction | limiting in particular in the upper limit of the glass transition temperature of resin p1, Usually, it is 200 degrees C or less.

  The resin p1 usually has a low haze. This is because polyphenylene ether and polystyrene polymer are excellent in dispersibility, so that polyphenylene ether and polystyrene polymer can be easily kneaded. A specific haze range may be set according to the degree of transparency required for the retardation layer. For example, the haze value of the resin p1 at a thickness of 1 mm is usually 10% or less, preferably 5% or less, and ideally 0%.

[1-2. Resin p2]
The resin p2 includes an alicyclic structure-containing polymer.
The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the repeating unit of the polymer, and has a polymer having an alicyclic structure in the main chain and an alicyclic structure in the side chain. Any of the polymers may be used. An alicyclic structure containing polymer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. Among these, a polymer containing an alicyclic structure in the main chain is preferable from the viewpoint of mechanical strength, heat resistance, and the like.

  Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure. Among these, from the viewpoints of mechanical strength, heat resistance and the like, a cycloalkane structure and a cycloalkene structure are preferable, and a cycloalkane structure is particularly preferable.

  The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, preferably 30 or less, more preferably 20 or less, particularly preferably per alicyclic structure. Is in the range of 15 or less, the mechanical strength, heat resistance, and film formability are highly balanced, which is preferable.

  The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected according to the purpose of use, preferably 30% by weight or more, more preferably 50% by weight or more, Preferably it is 70 weight% or more, Most preferably, it is 90 weight% or more. When the ratio of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is within this range, it is preferable from the viewpoint of the heat resistance of the retardation layer P2.

  Examples of alicyclic structure-containing polymers include norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrides thereof. Can be mentioned. Among these, norbornene-based polymers are preferable because of their good transparency and moldability.

Examples of the norbornene-based polymer include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, or a hydride thereof; An addition polymer of a monomer having a norbornene structure, an addition copolymer of a monomer having a norbornene structure and another monomer, or a hydride thereof can be given. Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, lightness, and the like. It is. Here, “(co) polymer” refers to a polymer and a copolymer.
Moreover, the polymer which has an alicyclic structure can be selected from the well-known polymer currently disclosed by Unexamined-Japanese-Patent No. 2002-321302, for example.

Among norbornene polymers, as a repeating unit, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.1 ^2,5 ] decane- It has a 7,9-diyl-ethylene structure, and the content of these repeating units is 90% by weight or more with respect to the entire repeating units of the norbornene polymer, and the content ratio of X and the content of Y It is preferable that the ratio to the ratio is 100: 0 to 40:60 in terms of a weight ratio of X: Y. By using such a resin, it is possible to obtain an optical laminate that has no dimensional change in the long term and is excellent in stability of optical characteristics.

Examples of the monomer that gives the repeating unit X include a norbornene monomer having a structure in which a five-membered ring is bonded to a norbornene ring. More specific examples of such monomers include tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene) and its derivatives (substituted on the ring). Group), and 7,8-benzotricyclo [4.3.0.1 ^0,5 ] dec-3-ene (common name: methanotetrahydrofluorene) and derivatives thereof.
Examples of monomers that give repeat unit Y include tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] deca-3,7-diene (common name: tetracyclododecene) and derivatives thereof (those having a substituent in the ring).

  Examples of means for obtaining such a norbornene-based polymer include: a) a monomer charge ratio in copolymerization with a) a monomer that gives a repeating unit X and a monomer that gives a repeating unit Y; And a method of hydrogenating unsaturated bonds in the polymer as necessary, and b) a polymer having a repeating unit X, and The method of mixing the polymer which has unit Y with a desired ratio is mentioned.

  The glass transition temperature of the alicyclic structure-containing polymer is preferably 115 ° C or higher, more preferably 120 ° C or higher. Moreover, although there is no restriction | limiting in particular in the upper limit of the glass transition temperature of an alicyclic structure containing polymer, Preferably it is 200 degrees C or less. By setting the glass transition temperature in such a range, the relaxation of the orientation of the resin p2 can be reduced, so that a retardation layer having excellent heat resistance can be realized.

  The molecular weight of the alicyclic structure-containing polymer was measured by gel permeation chromatography (hereinafter abbreviated as “GPC”) using cyclohexane (toluene when the polymer is not dissolved) as a solvent. The weight average molecular weight (Mw) in terms of polystyrene is usually 5,000 to 100,000, preferably 8,000 to 80,000, more preferably 10,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the optical laminate are highly balanced, which is preferable.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic structure-containing polymer is not particularly limited, but is preferably 1.0 to 10.0, more preferably 1.0 to 4. 0, even more preferably in the range of 1.2 to 3.5.

  The alicyclic structure-containing polymer has a resin component (that is, oligomer component) having a molecular weight of 2,000 or less, preferably 5% by weight or less, more preferably 3% by weight or less, and still more preferably 2% by weight. It is as follows. When the amount of the oligomer component is large, when the resin laminate is stretched, fine irregularities are generated on the surface or thickness unevenness occurs, resulting in poor surface accuracy.

  In order to reduce the amount of the oligomer component, the selection of the polymerization catalyst and the hydrogenation catalyst, the reaction conditions such as polymerization and hydrogenation, the temperature conditions in the step of pelletizing the resin as a molding material, etc. may be optimized. . The component amount of the oligomer can be measured by gel permeation chromatography using cyclohexane (toluene when the polymer does not dissolve).

  The resin p2 may contain an optional component other than the alicyclic structure-containing polymer as long as the effects of the present invention are not significantly impaired. Examples of optional components include antioxidants, heat stabilizers, light stabilizers, UV absorbers, antistatic agents, dispersants, chlorine scavengers, flame retardants, crystallization nucleating agents, antiblocking agents, antifogging agents, Examples include release agents, pigments, organic or inorganic fillers, neutralizers, lubricants, decomposition agents, metal deactivators, antifouling agents, antibacterial agents and other resins, and thermoplastic elastomers. The addition amount of an arbitrary component can be made into the range which does not impair the effect of this invention. Specifically, the addition amount of the optional component is usually 0 to 5 parts by weight, preferably 0 to 3 parts by weight with respect to 100 parts by weight of the alicyclic structure-containing polymer.

[1-3. Properties of optical laminates]
The optical layered body of the present invention includes a retardation layer P1 made of a resin p1 and a retardation layer P2 made of a resin p2. Such a layer composed of the resins p1 and p2 and having properties as a retardation layer can be obtained by stretching and pasting each of the resin p1 layer and the resin p2 layer. . A specific manufacturing method will be described later.

NZ coefficient _{NZ P1} of the retardation layer P1 is _{NZ P1} <0. By using the above-mentioned predetermined resin p1, the retardation layer P1 having NZ _P1 within the range can be easily obtained. The NZ _P1 is made within the range, it is possible to obtain an optical laminate having desired optical properties.
Meanwhile NZ coefficient _{NZ p2} retardation layer P2 may be a NZp2> 0.5.

In the optical layered body of the present invention, the retardation Re at an incident angle of 0 ° and the retardation R ₄₀ at an incident angle of 40 ° satisfy the relationship of 0.92 ≦ R ₄₀ /Re≦1.08. Satisfactory viewing angle compensation performance can be achieved by satisfying this relationship. The optical laminated body of the present invention can be made into a thin optical laminated body while satisfying such a relationship by using the above-mentioned predetermined resin p1.

It is preferable that the retardation layer P1 has a small thickness and a small retardation Rth (P1) in the thickness direction in order to obtain a thin optical laminate having a high viewing angle compensation performance. Specifically, the thickness of the retardation layer P1 is preferably 15 μm or less, more preferably 12 μm or less. Although the minimum of thickness is not specifically limited, For example, it can be 5 micrometers or more.
The retardation Rth (P1) in the thickness direction of the retardation layer P1 is preferably −50 nm or less, more preferably −60 nm or less. The lower limit of Rth (P1) is not particularly limited, but can be, for example, −200 nm or more.
The retardation layer P1 having such a thinness and a small Rth (P1) can be easily obtained by using the predetermined layer described above as the resin p1.
On the other hand, the thickness of the retardation layer P2 can be 30 μm or less. The lower limit of the thickness of the retardation layer P2 is not particularly limited, but may be, for example, 10 μm or more.

In the optical layered body of the present invention, the in-plane retardation Re (P1) and the thickness direction retardation Rth (P1) of the retardation layer P1, and the in-plane retardation Re (P2) and thickness of the retardation layer P2. The direction retardation Rth (P2) preferably satisfies the following formulas (1) and (2).
Re (P1) + Re (P2) ≧ 100 nm Formula (1)
−50 nm ≦ Rth (P1) + Rth (P2) ≦ 50 nm Formula (2)
When the retardations of the retardation layers P1 and P2 satisfy the expressions (1) and (2), it is possible to achieve a good viewing angle compensation performance. In this application, the optical laminated body which satisfy | fills Formula (1) and Formula (2) is obtained by using the predetermined thing mentioned above as resin p1 and resin p2, and extending | stretching these separately, and then bonding. It can be easily manufactured.

  The variation in the in-plane retardation Re of the entire optical laminate of the present invention is preferably within 10 nm, more preferably within 5 nm, and even more preferably within 2 nm. By setting the variation of the in-plane retardation Re within the above range, the display quality can be improved when used as a retardation film for a liquid crystal display device. Here, the variation of the in-plane retardation Re is when the front retardation at the time of light incident angle 0 ° (incident light beam and the surface of the laminate of the present invention are orthogonal) is measured in the width direction of the optical laminate ( That is, the difference between the maximum value and the minimum value of the measured front retardation value when the measurement is performed at a plurality of points on one line parallel to the width direction of the optical laminate.

In the optical laminate of the present invention, the variation of the slow axis in the in-plane direction is preferably within ± 5 °, more preferably within ± 3 °, and further preferably within ± 1 °.
By making the variation of the slow axis in the in-plane direction within the above range, when the optical laminate of the present invention is used as a retardation film and bonded to a polarizing plate in a liquid crystal display device, color unevenness and discoloration are eliminated. A good liquid crystal display can be provided.
The variation of the slow axis is the variation of each measured value with respect to the arithmetic average value of the measured values when the slow axis is measured at several points.

In the optical layered body of the present invention, the crossing angle between the slow axis of the retardation layer P1 and the slow axis of the retardation layer P2 is preferably 0 ° ± 10 °, more preferably 0 ° ± 5 °. Preferably there is.
By laminating the slow axis crossing angle to be in the above range, it is possible to reduce the light leakage and improve the viewing angle compensation performance when the optical laminate is incorporated in a liquid crystal display device. become.

  In the optical laminate of the present invention, the tear strength measured according to JIS K7128-1 is preferably 2 N / mm or more, more preferably 2.5 N / mm or more. By doing so, the optical layered body can be prevented from tearing when bonded to the polarizing plate, and the yield can be improved. The upper limit of the tear strength is not particularly limited, but may be, for example, 50 N / mm or less.

  The optical layered body of the present invention can be easily manufactured and highly compensated for birefringence. Therefore, the optical layered body can be used as a phase difference plate having excellent viewing angle dependency or by laminating a polarization separation layer on the optical layered body. The improvement film can be widely applied to display devices such as liquid crystal display devices and organic EL display devices.

[1-4. Manufacturing method of optical laminate]
The optical layered body of the present invention can be manufactured by a manufacturing method including the following steps (i) to (v) (hereinafter simply referred to as “the manufacturing method of the present invention”).
Step (i): A step of coextruding the resin p1 and the resin p3 containing a (meth) acrylic polymer to obtain a film PF (I) before stretching.
Step (ii): A step of stretching the unstretched film PF (I) to obtain a stretched multilayer film F (I) including a retardation layer P1 made of a resin p1 and a protective layer P3 made of a resin p3.
Step (iii): A step of extruding the resin p2 containing the alicyclic structure-containing polymer to obtain a pre-stretching film PF (II).
Step (iv): A step of stretching the unstretched film PF (II) to obtain the film F (II) of the retardation layer P2.
Step (v): A step of bonding the retardation layer P1 and the retardation layer P2.

The production method of the present invention further includes:
Step (vi): A step of peeling off the protective layer P3 from the retardation layer P1.
Can be included.

[1-5. Resin p3]
Resin p3 is a resin containing a (meth) acrylic polymer. (Meth) acrylic polymer means a polymer of (meth) acrylic acid or a (meth) acrylic acid derivative. Examples of the (meth) acrylic polymer include homopolymers and copolymers such as acrylic acid, acrylic acid ester, acrylamide, acrylonitrile, methacrylic acid, and methacrylic acid ester. Since the (meth) acrylic polymer has high strength and is hard, the retardation layer P1 can be appropriately protected by the protective layer P3, so that breakage when the pre-stretching film PF (I) is stretched can be prevented.

  As the (meth) acrylic polymer, a polymer containing a structural unit formed by polymerizing a (meth) acrylic acid ester is preferable. Examples of (meth) acrylic acid esters include alkyl esters of (meth) acrylic acid. Especially, the thing derived from (meth) acrylic acid and a C1-C15 alkanol or cycloalkanol is preferable, and the thing derived from a C1-C8 alkanol is more preferable. By reducing the number of carbon atoms as described above, the elongation at break of the optical laminate can be increased.

  Specific examples of the acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, sec-butyl acrylate, and t-acrylate. -Butyl, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, n-decyl acrylate, n-dodecyl acrylate, and the like.

  Specific examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, sec-butyl methacrylate, methacrylic acid. Examples thereof include t-butyl acid, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, n-decyl methacrylate, and n-dodecyl methacrylate.

  Furthermore, the (meth) acrylic acid ester may have a substituent such as a hydroxyl group or a halogen atom as long as the effects of the present invention are not significantly impaired. Examples of the (meth) acrylic acid ester having such a substituent include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-methacrylic acid 2- Examples include hydroxypropyl, 4-hydroxybutyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, and glycidyl methacrylate. One of these may be used alone, or two or more of these may be used in combination at any ratio.

  Further, the (meth) acrylic polymer may be a polymer of only (meth) acrylic acid or (meth) acrylic acid derivatives, and can be copolymerized with (meth) acrylic acid or (meth) acrylic acid derivatives. Copolymers with various monomers may be used. Examples of the copolymerizable monomer include α, β-ethylenically unsaturated carboxylic acid monomer other than (meth) acrylic acid ester, and α, β-ethylenically unsaturated carboxylic acid monomer. Alkenyl aromatic monomer, conjugated diene monomer, non-conjugated diene monomer, carboxylic acid unsaturated alcohol ester, and olefin monomer. One of these may be used alone, or two or more of these may be used in combination at any ratio.

  Specific examples of α, β-ethylenically unsaturated carboxylic acid ester monomers other than (meth) acrylic acid esters include dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, and dimethyl itaconate. It is done.

  The α, β-ethylenically unsaturated carboxylic acid monomer may be any of a monocarboxylic acid, a polyvalent carboxylic acid, a partial ester of a polyvalent carboxylic acid, and a polyvalent carboxylic acid anhydride. Specific examples thereof include crotonic acid, maleic acid, fumaric acid, itaconic acid, monoethyl maleate, mono n-butyl fumarate, maleic anhydride, itaconic anhydride and the like.

  Specific examples of the alkenyl aromatic monomer include styrene, α-methylstyrene, methyl α-methylstyrene, vinyl toluene and divinylbenzene.

  Specific examples of the conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, and 2-chloro-1. , 3-butadiene, cyclopentadiene and the like.

  Specific examples of the non-conjugated diene monomer include 1,4-hexadiene, dicyclopentadiene, ethylidene norbornene and the like.

  Specific examples of the carboxylic acid unsaturated alcohol ester monomer include vinyl acetate.

  Specific examples of the olefin monomer include ethylene, propylene, butene, pentene and the like.

  When the (meth) acrylic polymer contains a copolymerizable monomer, the content of the structural unit formed by polymerizing (meth) acrylic acid or a (meth) acrylic acid derivative in the (meth) acrylic polymer Is preferably 50% by weight or more, more preferably 85% by weight or more, and particularly preferably 90% by weight or more.

Moreover, a (meth) acrylic polymer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
Of these (meth) acrylic polymers, polymethacrylate is preferable, and polymethyl methacrylate is more preferable.

  The resin p3 may contain rubber particles. By including the rubber particles, the flexibility of the resin p3 can be increased and the impact resistance can be improved. Moreover, since the unevenness | corrugation is formed in the surface of the protective layer P3 by a rubber particle, and the contact area in the surface of the said protective layer P3 reduces, normally, the slipperiness of the surface of the protective layer P3 can be improved.

  Examples of the rubber forming the rubber particles include acrylate polymer rubber, polymer rubber mainly composed of butadiene, and ethylene-vinyl acetate copolymer rubber. Examples of the acrylate polymer rubber include those having butyl acrylate, 2-ethylhexyl acrylate or the like as a main component of a monomer unit. Among these, acrylic acid ester polymer rubber mainly composed of butyl acrylate and polymer rubber mainly composed of butadiene are preferable.

  The rubber particles may contain two or more types of rubber. Further, these rubbers may be mixed uniformly, but may be layered. Examples of rubber particles in which rubber is layered include a core composed of a rubber elastic component obtained by grafting an alkyl acrylate such as butyl acrylate and styrene, and one or both of polymethyl methacrylate and methyl methacrylate and an alkyl acrylate. Examples thereof include particles in which a hard resin layer (shell) made of a polymer forms a layer with a core-shell structure.

  The rubber particles preferably have a number average particle diameter of 0.05 μm or more, more preferably 0.1 μm or more, and preferably 0.3 μm or less, and 0.25 μm or less. Is more preferable. By setting the number average particle diameter within the above range, moderate unevenness can be formed on the surface of the protective layer P3, and the slipperiness of the laminate can be improved.

  The amount of the rubber particles is preferably 5 parts by weight or more and preferably 50 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer. By setting the amount of the rubber particles within the above range, the impact resistance of the laminate can be increased and the handling property can be improved.

  Moreover, the resin p3 may contain components other than the (meth) acrylic polymer and the rubber particles as long as the effects of the present invention are not significantly impaired. For example, other polymers may be included in addition to the (meth) acrylic polymer. However, from the viewpoint of remarkably exhibiting the advantages of the present invention, the amount of the polymer other than the (meth) acrylic polymer in the resin p3 is preferably small. The specific amount of the polymer other than the (meth) acrylic polymer is, for example, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, with respect to 100 parts by weight of the (meth) acrylic polymer, and 3 parts by weight or less. Is more preferable. Among these, it is particularly preferable that it is not contained at all.

  In addition, the resin p3 may contain a compounding agent, for example. As an example of a compounding agent, the same example as the compounding agent which resin p1 may contain is mentioned. In addition, a compounding agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. Further, the amount of the compounding agent can be appropriately determined within a range that does not significantly impair the effects of the present invention.

  The glass transition temperature of the resin p3 is usually 90 ° C. or higher, preferably 95 ° C. or higher, more preferably 100 ° C. or higher, and usually 145 ° C. or lower, preferably 140 ° C. or lower, more preferably 135 ° C. or lower. By making the glass transition temperature of the resin p3 higher than the lower limit of the above range, it is possible to suppress blocking when the resin pellets are dried at a high temperature. The temperature at the time of molding can be lowered, and foreign matters can be prevented from entering the film.

[1-6. Step (i): Film PF (I) Before Stretching]
The unstretched film PF (I) is a film obtained by coextrusion of the resin p1 and the resin p3, and is usually a multilayer film having layers of these resins. The unstretched film PF (I) may include two or more layers of the resin p1, but usually includes only one layer.
The thickness of the layer of the resin p1 in the unstretched film PF (I) can be set to an appropriate thickness so that a desired retardation is exhibited after stretching. The specific thickness of the layer of the resin p1 in the pre-stretched film PF (I) is preferably 10 μm or more, more preferably 20 μm or more from the viewpoint of obtaining sufficient retardation and mechanical strength. Flexibility and handling From the viewpoint of improving the property, the thickness is preferably 200 μm or less, more preferably 100 μm or less.

  The film PF (I) before stretching may include only one layer of the resin p3, but may include two or more layers.

  Usually, the unstretched film PF (I) is prepared as a long film. By making the film before stretching into a long film, the film F (I) obtained by stretching the film and the optical laminate as a product can also be produced as a long film. Here, the term “long” means that the film has a length of at least 5 times the width, preferably 10 times or more, specifically a roll. It has a length enough to be wound up into a shape and stored or transported. Although the upper limit of the magnification of the length with respect to the width is not particularly limited, it can be usually 5000 times or less. A long film can be produced in a production line while being continuously conveyed in the longitudinal direction. For this reason, when manufacturing a phase difference film, part or all of each process can be performed in-line, so that the manufacturing can be performed easily and efficiently.

  In the unstretched film PF (I), the variation in the layer thickness of the resin p1 is preferably 1 μm or less over the entire surface. Thereby, the dispersion | variation in the color tone of retardation film can be made small. In addition, the color tone change after long-term use of the retardation film can be made uniform.

  In order to make the variation in the thickness of the layer of the resin p1 1 μm or less over the entire surface, for example, when using the coextrusion molding method, (1) a polymer filter having an opening of 20 μm or less is provided in the extruder; Rotate the gear pump at 5 rpm or higher; (3) place an enclosure around the die; (4) make the air gap 200 mm or less; (5) perform edge pinning when casting the film on a chill roll; and (6) As the extruder, a twin screw extruder or a double flight type single screw extruder may be used.

The layer thickness of the resin p1 is measured using a commercially available contact-type thickness meter, then the total thickness of the film is measured, then the thickness measurement part is cut and the cross section is observed with an optical microscope to obtain the thickness ratio of each layer, It can be calculated from the ratio. Moreover, the above operation is performed at regular intervals in the longitudinal direction and the width direction of the film, and the average value T _ave and the variation of the thickness can be obtained.
Here, the thickness variation (μm) is the larger of T _ave −T _min and T _max −T _ave . T _ave represents the arithmetic average value of the measured values measured above, T _max represents the maximum value of the measured thickness T, and T _min represents the minimum value.

  Moreover, it is preferable to reduce content of the residual solvent in film PF (I) before extending | stretching. Means for that purpose include (1) reducing the residual solvent of the resin used as a raw material; (2) pre-drying the resin before forming the pre-stretch film. For example, the preliminary drying is performed by a hot air dryer or the like in the form of pellets or the like. The drying temperature is preferably 100 ° C. or more, and the drying time is preferably 2 hours or more. By performing preliminary drying, the residual solvent contained in the pre-stretched film can be reduced, and foaming of the extruded sheet-like resin can be prevented.

  Examples of specific methods of coextrusion of the resin p1 and the resin p3 include, for example, a coextrusion T-die method, a coextrusion inflation method, a coextrusion lamination method, and the like. preferable. Further, the coextrusion T-die method includes a feed block method and a multi-manifold method, but the multi-manifold method is particularly preferable in that variation in thickness can be reduced.

  When the co-extrusion T-die method is employed, the melting temperature of the resin in the extruder having the T-die is preferably 80 ° C. higher than the glass transition temperature of the resin p1 and the resin p3, and a temperature higher by 100 ° C. It is more preferable to set it above, and it is preferable that the temperature be 180 ° C. or higher, and it is more preferable that the temperature be 150 ° C. or higher. By setting the melting temperature in the extruder to not less than the lower limit of the above range, the fluidity of the resin can be made sufficiently high, and by making it not more than the upper limit, deterioration of the resin can be prevented.

In the extrusion molding method, a sheet-like molten resin extruded from an opening of a die is brought into close contact with a cooling drum. The method for bringing the molten resin into close contact with the cooling drum is not particularly limited, and examples thereof include an air knife method, a vacuum box method, and an electrostatic contact method.
The number of cooling drums is not particularly limited, but is usually two or more. Examples of the arrangement method of the cooling drum include, but are not limited to, a linear type, a Z type, and an L type. Further, the way of passing the molten resin extruded from the opening of the die through the cooling drum is not particularly limited.

  The degree of adhesion of the extruded sheet-like resin to the cooling drum varies depending on the temperature of the cooling drum. When the temperature of the cooling drum is raised, the adhesion is improved. However, if the temperature is raised too much, the sheet-like resin may not be peeled off from the cooling drum, and there is a possibility that a problem of winding around the drum may occur. Therefore, the temperature of the cooling drum is preferably (Tg + 30) ° C. or less, more preferably (Tg-5) ° C. to (Tg−), where Tg is the glass transition temperature of the resin in the layer that is extruded from the die and contacts the drum. 45) Set to a range of ° C. By doing so, problems such as slipping and scratches can be prevented.

[1-7. Step (ii): Stretched multilayer film F (I)]
By stretching the unstretched film PF (I), a stretched multilayer film F (I) including a retardation layer P1 made of a resin p1 and a protective layer P3 made of a resin p3 is obtained. Since the protective layer P3 having a high strength is provided in contact with the retardation layer P1 having a relatively low strength, the stretching can be executed without causing breakage due to the stretching. Further, since the retardation layer P1 is protected by the protective layer P3, the components of the retardation layer P1 do not cause bleed-out at the boundary between the retardation layer P1 and the protective layer P3. Therefore, since the optical laminate can be stably produced in-line, it is possible to efficiently produce a long optical laminate.

  Examples of the stretching operation include a method of uniaxial stretching in the longitudinal direction using a difference in peripheral speed between rolls (longitudinal uniaxial stretching); a method of uniaxial stretching in the width direction using a tenter (lateral uniaxial stretching); A method of sequentially performing uniaxial stretching and lateral uniaxial stretching (sequential biaxial stretching); a method of stretching in an oblique direction with respect to the longitudinal direction of the film before stretching (oblique stretching);

  The film temperature at the time of stretching is preferably Tg-20 to Tg + 20 ° C, more preferably Tg-5 to Tg + 5 ° C, where Tg (° C) is the glass transition temperature of the resin p1. Moreover, a draw ratio can be 1.5-8.0 times, for example. The number of stretching may be one time or two or more times.

Moreover, when manufacturing the extending | stretching multilayer film F (I) from the film PF (I) before extending | stretching, you may perform processes other than the above-mentioned.
For example, the pre-stretched film PF (I) may be preheated before being stretched. Examples of the means for heating the pre-stretched film include an oven-type heating device, a radiation heating device, or immersion in a liquid. Of these, an oven-type heating device is preferable. The heating temperature in the preheating step is usually a stretching temperature of −40 ° C. or higher, preferably a stretching temperature of −30 ° C. or higher, and is usually a stretching temperature of + 20 ° C. or lower, preferably a stretching temperature of + 15 ° C. or lower. The stretching temperature means the set temperature of the heating device.

In addition, for example, the obtained optical layered body may be subjected to immobilization treatment. The temperature in the fixing treatment is usually room temperature or higher, preferably “stretching temperature−40 ° C.” or higher, and usually “stretching temperature + 30 ° C.” or lower, preferably “stretching temperature + 20 ° C.” or lower.
Further, if necessary, other films such as a mat layer, a hard coat layer, an antireflection layer, and an antifouling layer may be bonded together in order to protect the optical laminate and improve the handleability.

[1-8. Steps (iii) and (iv): Film PF (II) and Film F (II) before Stretching]
In step (iii), the resin p2 is extruded to obtain a pre-stretching film PF (II). The extrusion temperature can be appropriately selected according to the glass transition temperature of the resin p2. The thickness of the film PF (II) before stretching can be appropriately adjusted so that the thickness of the retardation layer P2 after stretching becomes a desired thickness. The film PF (II) before stretching is usually prepared as a long film as well as the film PF (I) before stretching.

  In step (iv), the unstretched film PF (II) is stretched to obtain the film F (II) of the retardation layer P2. Stretching can usually be performed by uniaxial stretching. The specific method of stretching is not particularly limited, and the same method as that described in step (ii) can be adopted.

  The stretching temperature in step (iv) is preferably between (Tg-30 ° C) and (Tg + 60 ° C), more preferably (Tg-10 ° C) to (Tg + 50 ° C), where Tg is the glass transition temperature of the resin p2. Temperature range. Moreover, a draw ratio is 1.01-30 times normally, Preferably it is 1.01-10 times, More preferably, it is 1.01-5 times. The stretching conditions in step (iv) can be appropriately adjusted so that the obtained optical laminate has a desired retardation.

[1-9. Step (v)]
In the step (v), the retardation layer P1 and the retardation layer P2 are bonded. That is, the stretched multilayer film F (I) and the film F (II) are bonded in such a manner that the retardation layer P1 and the retardation layer P2 are bonded. Therefore, for example, when the protective layer P3 exists on both surfaces of the stretched multilayer film F (I), bonding is performed after peeling at least one of them.

  The bonding in the step (v) can be performed using an appropriate bonding means such as an adhesive or a pressure-sensitive adhesive. Examples of the adhesive or pressure-sensitive adhesive include acrylic, silicone, polyester, polyurethane, polyether, rubber, and the like. Among these, an acrylic type is preferable from the viewpoint of heat resistance and transparency.

  Bonding in the step (v) can be performed by roll-to-roll. That is, the long stretched multilayer film F (I) and the long film F (II) are respectively unwound, and the operation of applying an adhesive or a pressure-sensitive adhesive and bonding are continuously performed. A paste can be obtained. Efficient manufacture can be performed by bonding of this aspect.

In the bonding in the step (v), the crossing angle between the slow axis of the retardation layer P1 and the slow axis of the retardation layer P2 in the stretched composite film (I) is preferably 0 ± 10 °. Preferably, it is performed so as to be 0 ° ± 5 °.
In the bonding at such an angle, in the stretching in the step (ii) and the step (iv), stretching is performed so that each slow axis with respect to the longitudinal direction of the long film is in a predetermined direction, and the step (v) Can be achieved by performing roll-to-roll bonding. However, the present invention is not limited to this, and the stretched composite film F (I) and the film F (II) may be bonded at an angle that does not align the longitudinal direction so that the slow axes are aligned.

[1-10. Step (vi)]
In the step (vi), the protective layer P3 is peeled from the retardation layer P1. Step (vi) can be performed at any feasible stage. For example, it can be performed at any stage from the end of step (ii) to the end of step (v). Or it can also carry out after bonding the optical laminated body of this invention with another member (polarizing plate etc.). As described above, by providing the protective layer P3, good stretching can be performed without causing breakage, but the protective layer P3 may not be necessary in the use of the optical laminate. In that case, by performing the step (vi), it is possible to obtain a thin optical laminate while realizing good stretching.

  The optical layered body obtained by the production method of the present invention may have a long shape. Such an optical layered body may include a layer having a long shape as the retardation layer P1, and a layer having a long shape as the retardation layer P2. Such an optical laminate is prepared by preparing a film PF (I) before stretching and a film PF (II) before stretching as long films, and stretching them to stretch the multilayered film F (I) and the film F (II). ) Can be obtained as long films, and these can be used in step (v) for roll-to-roll bonding.

  When manufacturing an optical laminate having a long shape, in such a long optical laminate, the retardation layer P1 has a slow axis in its width direction, and the retardation layer P2 also has a slow phase in its width direction. It is preferable to have an axis. Such an optical layered body can be preferably used as a viewing angle compensation layer of a polarizing plate.

[2. Polarizing plate composite]
The polarizing plate composite of the present invention includes the optical laminate of the present invention and a polarizer.
As a polarizer, for example, a film made of a suitable vinyl alcohol-based polymer according to the prior art such as polyvinyl alcohol or partially formalized polyvinyl alcohol, a dyeing treatment with a dichroic substance made of iodine or a dichroic dye, a stretching treatment In addition, an appropriate treatment such as a crosslinking treatment can be performed in an appropriate order and method, and an appropriate material that transmits linearly polarized light when natural light is incident can be used. In particular, those excellent in light transmittance and degree of polarization are preferable. The thickness of the polarizer is generally 5 to 80 μm, but is not limited thereto.

  The polarizer may be provided on either the retardation layer P1 side or the retardation layer P2 side of the optical laminate of the present invention, but is preferably provided on the retardation layer P2 side. The polarizer may be provided in direct contact with the retardation layer P1 or the retardation layer P2, but may be provided through another layer. For example, a normal polarizing plate has a structure composed of a polarizer and a protective layer provided on one or both sides of the polarizer, so that the polarizer has the retardation layer P1 or retardation layer P2 via the protective layer. It may be provided above.

As a material for the protective layer, an appropriate transparent film can be used. Among them, a film made of a polymer excellent in transparency, mechanical strength, thermal stability, moisture shielding property, etc. is preferably used. Examples of the polymer include acetate resins such as triacetyl cellulose, polyester resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, polymer resins having an alicyclic structure, Acrylic resins and the like can be mentioned. Among them, acetate resins or polymer resins having an alicyclic structure are preferable from the viewpoint of low birefringence. From the viewpoints of transparency, low hygroscopicity, dimensional stability, lightness, and the like. A polymer resin having an alicyclic structure is particularly preferable.
The thickness of the protective layer is arbitrary, but is generally 500 μm or less, preferably 5 to 300 μm, particularly preferably 5 to 150 μm for the purpose of reducing the thickness of the polarizing plate.

  A polarizer or a polarizing plate may be provided by laminating on the retardation layer P2 via an adhesive or pressure-sensitive adhesive layer. Examples of the adhesive or pressure-sensitive adhesive include acrylic, silicone, polyester, polyurethane, polyether, rubber, and the like. Among these, an acrylic type is preferable from the viewpoint of heat resistance and transparency.

  In the polarizing plate composite, the slow axis of the optical laminate and the transmission axis of the polarizer are preferably parallel or orthogonal. Such a polarizing plate composite is prepared by preparing a long optical laminate and a polarizing plate in which the direction of the slow axis and the transmission axis with respect to the longitudinal direction is in a desired state, and laminating them by roll-to-roll. Can be manufactured efficiently.

  The thickness of the polarizing plate composite of the present invention is usually 100 to 700 μm, preferably 200 to 600 μm.

[3. Application: Liquid crystal display]
The optical laminate of the present invention and the polarizing plate composite of the present invention can be preferably used as a component of a liquid crystal display device. For example, the optical layered body of the present invention can be provided on one or both sides of a liquid crystal cell of a liquid crystal display device. Specifically, an embodiment in which the optical laminate is disposed between the polarizing plate and the liquid crystal cell; or an embodiment in which the optical laminate is disposed on the surface of the polarizing plate opposite to the liquid crystal cell is exemplified. When the optical laminate and polarizing plate laminate of the present invention are long, they can be cut into an appropriate size and then incorporated into a liquid crystal display device.
The liquid crystal display device of the present invention is formed with a suitable structure according to the prior art, such as a transmissive type, a reflective type, or a transmissive / reflective type in which a polarizing plate is arranged on one or both sides of a liquid crystal cell. Can do. The liquid crystal modes used in the liquid crystal cell include TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, HAN (Hybrid Alignment Nematic) type, VA (Vertical Alignment), MVA (Multi-type Inlet). Plane Switching) type, OCB (Optical Compensated Bend) type, and the like.

  In a preferred example, the liquid crystal display device of the present invention is an IPS mode liquid crystal display device including an incident side polarizer, a liquid crystal cell, and an output side polarizer in this order, and at least one of the incident side polarizer and the output side polarizer. The optical laminate of the present invention is provided between the liquid crystal cell and the liquid crystal cell. In this example, in the optical laminate, the crossing angle between the slow axis of the retardation layer P1 and the slow axis of the retardation layer P2 is 0 ° ± 10 °, and the retardation layer P1 of the optical laminate is a liquid crystal cell. It is particularly preferred that they are arranged on the side. By having such a configuration, the adhesiveness between the retardation layer and the polarizer can be increased.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples shown below, and the scope of the claims of the present invention and the equivalents thereof are not deviated from. Any change can be made.
In the following description, “%” and “parts” representing amounts are based on weight unless otherwise specified.
Further, the operations described below were performed under normal temperature and normal pressure conditions unless otherwise specified.

[Explanation of evaluation method]
(1) Glass transition temperature Based on JIS K7121, it measured by heating up at 20 degree-C / min using the differential scanning calorimetry (DSC).

(2) Thickness of film or laminate The cross section of the film or laminate was measured by observing with an optical microscope. The laminate was measured for each layer.

(3) Retardation and NZ coefficient Measured at a measurement wavelength of 550 nm using "AxoScan" manufactured by AXOMETRICS.

(4) Contrast Remove the polarizing plate and retardation film from the LCD panel of the tablet device (trade name “iPad”, 2nd generation, manufactured by Apple Inc.), and replace the polarizing plate multilayer body to be evaluated with an optical transparent Bonding was performed via an adhesive sheet (“LUCIACS CS9621T” manufactured by Nitto Denko Corporation).
The apparatus was started, and the brightness in bright display and dark display was measured by scanning in 5 ° increments in the range of azimuth angle 0 to 360 ° and polar angle 0 to 80 °.
Regarding the measured value at each viewing angle, the brightness obtained by dividing the brightness of the bright display by the brightness of the dark display was taken as the contrast at the viewing angle, and the lowest value within the viewing angle scanning range was taken as the contrast index.

Example 1
(1-1. Pellets of resin p1)
Syndiotactic polystyrene (“130-ZC” manufactured by Idemitsu Kosan Co., Ltd., glass transition temperature 98 ° C., crystallization temperature 140 ° C.) 70% by weight and poly (2,6-dimethyl-1,4-phenylene oxide) (Aldrich catalog) No. 18242-7) 30% by weight was kneaded with a twin-screw extruder to obtain transparent resin p1 pellets. The obtained resin p1 had a glass transition temperature of 125 ° C.

(1-2. Film PF (I) before stretching)
A film forming apparatus for two-type two-layer coextrusion molding was prepared, and the pellets of the resin p1 were put into one uniaxial extruder equipped with a double flight type screw and melted.

  The pellets of impact-resistant polymethyl methacrylate resin p3 (“SUMIPEX HT55X” manufactured by Sumitomo Chemical Co., Ltd.) were put into another uniaxial extruder equipped with a double flight type screw and melted.

  The melted 290 ° C. resin p1 is passed through a polymer filter in the form of a leaf disk having a mesh size of 10 μm to one manifold of a multi-manifold die (die slip surface roughness Ra: 0.1 μm). Was supplied to the other manifold through a polymer filter having a leaf disk shape of 10 μm.

  Resin p1 and resin p3 were simultaneously extruded from the multi-manifold die at 280 ° C. to form a film. The film-shaped molten resin thus formed was cast on a cooling roll adjusted to a surface temperature of 110 ° C., and then passed between two cooling rolls adjusted to a surface temperature of 50 ° C. to form a layer made of resin p1 (thickness 26 μm) ) And a layer made of resin p3 (thickness: 65 μm), and a film PF (I) before stretching having a thickness of 91 μm was obtained.

(1-3. Stretched multilayer film F (I))
The obtained film PF (I) before stretching was 125 ° C. equal to the glass transition temperature of the resin p1, and 2.0 times in the MD direction and 1 in the TD direction using a simultaneous biaxial stretching machine (manufactured by Toyo Seiki Co., Ltd.). The film was simultaneously biaxially stretched 3 times to obtain a stretched multilayer film F (I) of Re 60 nm and Rth-90 nm including the retardation layer P1 made of the resin p1 and the protective layer P3 made of the resin p3. The retardation layer P1 and the protective layer P3 were peelable, and the thickness of the retardation layer P1 was 10 μm, and the thickness of the P3 layer was 25 μm.

A part of the obtained film F (I) was cut out, and from this, the protective layer P3 was peeled off to obtain a sample. The NZ coefficient NZ _P1 , in-plane retardation Re (P1), and thickness direction retardation Rth (P1) of the retardation layer P1 of this sample were measured. As a result, NZ _P1 = −1.0, Re (P1) = 60 nm, and Rth (P1) = − 90 nm.

(1-4. Film F (II))
A single-layer film forming apparatus was prepared. Pellets of norbornene polymer p3 (“ZEONOR1420” manufactured by Nippon Zeon Co., Ltd., glass transition temperature 140 ° C.) are charged into a single-screw extruder equipped with a double-flight screw of a film forming apparatus and melted at 260 ° C. The film was formed into a film with a die (surface roughness Ra of die slip: 0.1 μm) adjusted to 260 ° C. through a 10 μm leaf disk-shaped polymer filter.

  The film-shaped molten resin thus formed was cast on a cooling roll adjusted to a surface temperature of 120 ° C., and then passed between two cooling rolls adjusted to a surface temperature of 50 ° C. to give a film PF (II )

The obtained unstretched film PF (II) was uniaxially stretched by 3.0 times in the TD direction using a simultaneous biaxial stretching machine (manufactured by Toyo Seiki Co., Ltd.) at 140 ° C. equal to the glass transition temperature of the norbornene resin. The magnification in the MD direction was 1.0), and a film F (II) of the retardation layer P2 having Re 90 nm, Rth 80 nm, and thickness 20 μm was obtained.
Using the obtained film F (II) as a sample, the in-plane retardation Re (P2) and the thickness direction retardation Rth (P2) of the retardation layer P2 were measured. As a result, Re (P2) = 90 nm and Rth (P2) = 80 nm.

(1-5. Optical laminated body with protective layer)
The surface of the stretched multilayer film F (I) obtained in (1-3) on the phase difference layer P1 side and one surface of the film F (II) obtained in (1-4) were bonded. The pasting was performed through an optical transparent adhesive sheet (“LUCIACS CS9621T” manufactured by Nitto Denko Corporation) so that the slow axes of the retardation layers P1 and P2 are in the same direction. As a result, an optical laminate F (III) with a protective layer having a layer configuration of (protective layer P3) / (retardation layer P1) / (adhesive sheet layer) / (retardation layer P2) was obtained. The protective layer P3 of the multilayer body F (III) was in a state where it could be peeled off from the retardation layer P1.

A part of the obtained laminate F (III) is cut out, and from this, the protective layer P3 is peeled off, and this has a layer configuration of (retardation layer P1) / (adhesive sheet layer) / (retardation layer P2) A sample of the inventive optical laminate was obtained. This sample was measured for retardation Re at an incident angle of 0 ° and retardation R ₄₀ at an incident angle of 40 °. Re = 150 nm and R ₄₀ = 145 nm.

  Furthermore, when the sample was heated in an oven at 80 ° C. for 500 hours and then Re was measured again, it was 149 nm.

(1-6. Polarizing plate composite)
The surface on the phase difference layer P2 side of the optical layered body F (III) with a protective layer obtained in (1-5) and the polarizing plate (manufactured by Sanlitz, LLC2-5618) were bonded. The pasting was performed through an optical transparent adhesive sheet (“LUCIACS CS9621T” manufactured by Nitto Denko Corporation) so that the slow axis of the laminate F (III) and the absorption axis of the polarizing plate were orthogonal to each other. Thereafter, the protective layer P3 of the laminate F (III) was peeled off to obtain a polarizing plate composite. The polarizing plate composite has a layer structure of (retardation layer P1) / (adhesive sheet layer) / (retardation layer P2) / (adhesive sheet) / (polarizing plate). The part of (P1) / (adhesive sheet layer) / (retardation layer P2) comprised the optical laminated body of this invention.

  About the obtained polarizing plate composite_body | complex, the contrast was evaluated by the said method.

(Example 2)
Except for the following changes, the same operation as in Example 1 was performed to obtain and evaluate a polarizing plate composite and its components.
・ In the production of pellets of resin p1 in (1-1), the addition amounts of syndiotactic polystyrene and poly (2,6-dimethyl-1,4-phenylene oxide) were changed to 74 wt% and 26 wt%, respectively. did. The obtained resin p1 had a glass transition temperature of 120 ° C.
In the production of the stretched multilayer film F (I) of (1-3), the stretching temperature was changed to 120 ° C. which is equal to the glass transition temperature of the resin p1. Further, in the production of the pre-stretching film PF (I) of (1-2), the thickness of the resin p1 during the extrusion of the resin p1 and the resin p3 was adjusted. With this adjustment, the values of Re (P1) and Rth (P1) were set to the same values as in Example 1 (60 nm and −90 nm) by the same stretching ratio as in Example 1. The thickness of the retardation layer P1 was 8 μm.

(Example 3)
Except for the following changes, the same operation as in Example 1 was performed to obtain and evaluate a polarizing plate composite and its components.
・ In the production of pellets of resin p1 in (1-1), the addition amounts of syndiotactic polystyrene and poly (2,6-dimethyl-1,4-phenylene oxide) were changed to 66 wt% and 34 wt%, respectively. did. The obtained resin p1 had a glass transition temperature of 132 ° C.
In the production of the stretched multilayer film F (I) of (1-3), the stretching temperature was changed to 132 ° C. which is equal to the glass transition temperature of the resin p1. Further, in the production of the pre-stretching film PF (I) of (1-2), the thickness of the resin p1 during the extrusion of the resin p1 and the resin p3 was adjusted. With this adjustment, the values of Re (P1) and Rth (P1) were set to the same values as in Example 1 (60 nm and −90 nm) by the same stretching ratio as in Example 1. The thickness of the retardation layer P1 was 15 μm.

(Comparative Example 1)
Except for the following changes, the same operation as in Example 1 was performed to obtain and evaluate a polarizing plate composite and its components.
・ In the production of pellets of resin p1 in (1-1), the addition amounts of syndiotactic polystyrene and poly (2,6-dimethyl-1,4-phenylene oxide) were changed to 100% by weight and 0% by weight, respectively. did. The obtained resin p1 had a glass transition temperature of 98 ° C.
In the production of the stretched multilayer film F (I) of (1-3), the stretching temperature was changed to 98 ° C. which is equal to the glass transition temperature of the resin p1. Further, in the production of the pre-stretching film PF (I) of (1-2), the thickness of the resin p1 during the extrusion of the resin p1 and the resin p3 was adjusted. With this adjustment, the values of Re (P1) and Rth (P1) were set to the same values as in Example 1 (60 nm and −90 nm) by the same stretching ratio as in Example 1. The thickness of the retardation layer P1 was 5 μm.

(Comparative Example 2)
Except for the following changes, the same operation as in Example 1 was performed to obtain and evaluate a polarizing plate composite and its components.
・ In the production of pellets of resin p1 in (1-1), the addition amounts of syndiotactic polystyrene and poly (2,6-dimethyl-1,4-phenylene oxide) were changed to 85 wt% and 15 wt%, respectively. did. The obtained resin p1 had a glass transition temperature of 112 ° C.
In the production of the stretched multilayer film F (I) of (1-3), the stretching temperature was changed to 112 ° C. which is equal to the glass transition temperature of the resin p1. Further, in the production of the pre-stretching film PF (I) of (1-2), the thickness of the resin p1 during the extrusion of the resin p1 and the resin p3 was adjusted. With this adjustment, the values of Re (P1) and Rth (P1) were set to the same values as in Example 1 (60 nm and −90 nm) by the same stretching ratio as in Example 1. The thickness of the retardation layer P1 was 7 μm.

(Comparative Example 3)
Except for the following changes, the same operation as in Example 1 was performed to obtain and evaluate a polarizing plate composite and its components.
・ In the production of pellets of resin p1 in (1-1), the addition amounts of syndiotactic polystyrene and poly (2,6-dimethyl-1,4-phenylene oxide) were changed to 62% by weight and 38% by weight, respectively. did. The obtained resin p1 had a glass transition temperature of 138 ° C.
In the production of the stretched multilayer film F (I) of (1-3), the stretching temperature was changed to 138 ° C. which is equal to the glass transition temperature of the resin p1. Further, in the production of the pre-stretching film PF (I) of (1-2), the thickness of the resin p1 during the extrusion of the resin p1 and the resin p3 was adjusted. With this adjustment, the values of Re (P1) and Rth (P1) were set to the same values as in Example 1 (60 nm and −90 nm) by the same stretching ratio as in Example 1. The thickness of the retardation layer P1 was 20 μm.

  The evaluation results of Examples and Comparative Examples are shown in Table 1.

[Consideration]
As is apparent from the results shown in Table 1, in Examples 1 to 3, the ratio of polyphenylene ether: syndiotactic polystyrene polymer was superior to Comparative Examples 1 to 3 that did not satisfy the requirements of the present invention. Evaluation results were obtained. Specifically, it was possible to construct a display device having a small thickness, a small decrease in Re due to processing at 80 ° C. × 500 hours, and good contrast.

Claims (13)

A retardation layer P1 made of a resin p1 containing a polyphenylene ether and a polystyrene-based polymer having a syndiotactic structure;
An optical laminate comprising a retardation layer P2 made of a resin p2 containing an alicyclic structure-containing polymer,
In the resin p1, the weight ratio of the content of the polyphenylene ether / the content of the polystyrene polymer is larger than 25/75 and smaller than 35/65.
NZ coefficient _{NZ P1} of the retardation layer P1 is a _{NZ P1} <0,
An optical laminate in which retardation Re at an incident angle of 0 ° and retardation R ₄₀ at an incident angle of 40 ° satisfy the relationship of 0.92 ≦ R ₄₀ /Re≦1.08. In-plane retardation Re (P1) and thickness direction retardation Rth (P1) of the retardation layer P1, and in-plane retardation Re (P2) and thickness direction retardation Rth (P2) of the retardation layer P2, The following formula (1) and formula (2):
Re (P1) + Re (P2) ≧ 100 nm Formula (1)
−50 nm ≦ Rth (P1) + Rth (P2) ≦ 50 nm Formula (2)
The optical laminate according to claim 1, wherein   The optical laminated body according to claim 1 or 2, wherein the retardation layer P1 has a thickness of 15 µm or less, and a retardation Rth (P1) in the thickness direction is -50 nm or less. The polyphenylene ether has a weight average molecular weight of 15,000 to 100,000;
The optical laminated body of any one of Claims 1-3 whose weight average molecular weights of the said polystyrene-type polymer are 130,000-300,000.   The optical laminated body according to any one of claims 1 to 4, wherein a crossing angle between a slow axis of the retardation layer P1 and a slow axis of the retardation layer P2 is 0 ° ± 10 °. .   A polarizing plate composite comprising the optical laminate according to any one of claims 1 to 5 and a polarizer.   The polarizing plate composite according to claim 6, wherein a slow axis of the optical laminate and an absorption axis of the polarizer are orthogonal to each other.   A liquid crystal display comprising the polarizing plate composite according to claim 6 and a liquid crystal cell. An in-plane switching mode liquid crystal display device including an incident side polarizer, a liquid crystal cell, and an output side polarizer in this order,
6. The liquid crystal display device according to claim 5, further comprising a position between the incident-side polarizer and the liquid crystal cell, a position between the output-side polarizer and the liquid crystal cell, or both positions. With an optical laminate of
The optical layered body is an in-plane switching mode liquid crystal display device in which the retardation layer P1 is disposed on the liquid crystal cell side. It is a manufacturing method of the optical layered product according to any one of claims 1 to 5,
A resin p1 comprising a polyphenylene ether and a polystyrene polymer having a syndiotactic structure, wherein a weight ratio of the content of the polyphenylene ether / the content of the polystyrene polymer is larger than 25/75 and smaller than 35/65; Coextruding the resin p3 containing a (meth) acrylic polymer to obtain a pre-stretching film PF (I);
Stretching the pre-stretched film PF (I) to obtain a stretched multilayer film F (I) including the retardation layer P1 made of the resin p1 and the protective layer P3 made of the resin p3;
Extruding the resin p2 containing the alicyclic structure-containing polymer to obtain a film PF (II) before stretching;
Stretching the pre-stretched film PF (II) to obtain a film F (II) of the retardation layer P2, and
The manufacturing method which has the process of bonding the said phase difference layer P1 and the said phase difference layer P2.   The manufacturing method of Claim 10 which further includes the process of peeling the said protective layer P3 from the said phase difference layer P1. The obtained optical laminated body has a long shape including the retardation layer P1 having a long shape and the retardation layer P2 having a long shape,
The retardation layer P1 has a slow axis in its width direction,
The said retardation layer P2 is a manufacturing method of Claim 10 or 11 which has a slow axis in the width direction.   The manufacturing method of a elongate polarizing plate composite which has the process of bonding the elongate optical laminated body obtained by the manufacturing method of Claim 12, and a elongate polarizer with a roll to roll.