TW201922484A - Composite retardation plate, optical laminate, and image display device - Google Patents

Abstract

This invention provides a composite retardation plate capable of suppressing occurring of wrinkle at bent portion while the composite retardation plate is bent due to the contacting with a roll-shaped member or disposing on the surface of an image display device panel having a bent portion or the like during the processes of transporting, winding and the likes. Provided is a composite retardation film including a first retardation layer, a second retardation layer, and a first adhesive layer binding the first retardation layer and the second retardation layer, wherein, the piercing inclination per unit thickness is 6 kg/mm2 to 15 kg/mm2.

Description

 Composite phase difference plate, optical laminate, and image display device  

The present invention relates to a composite phase difference plate, an optical layered body including the composite phase difference plate, and an image display device including the optical layered body.

Conventionally, in an image display device, an optical layered body having antireflection performance is disposed on the visual recognition side of the image display panel to suppress a decrease in visibility due to reflection of external light.

An optical laminate having an antireflection property is known as an optical laminate comprising a polarizing plate and a retardation layer. The optical layering system having anti-reflection properties converts the external light toward the image display panel into linearly polarized light by a polarizing plate, and then converts into circularly polarized light by the phase difference layer. The external light that is circularly polarized is reflected on the surface of the image display panel, but the direction of rotation of the polarizing surface is reversed during the reflection, and is converted into linear polarized light by the phase difference layer, and then blocked by the polarizing plate. As a result, it is possible to remarkably suppress the light from being emitted to the outside.

As the phase difference plate having the constituent elements of the optical layered body having antireflection performance, a composite phase difference plate in which a plurality of retardation layers are formed by an adhesive layer is known. For example, Patent Literatures 1 and 2 disclose a composite phase difference plate in which a 1/2 wavelength layer and a 1/4 wavelength layer are subsequently laminated.

 [Previous Technical Literature]    [Patent Literature]  

Patent Document 1: Japanese Patent Laid-Open No. 2015-21975

Patent Document 2: JP-A-2015-21976

When the composite phase difference plate is used alone or in the form of an optical layered body including the composite phase difference plate, it may be in contact with the roller-shaped member or may be disposed in a curved portion in the step of being conveyed, wound, or the like. The image shows the surface of the panel, etc., and when the composite phase difference plate is bent, wrinkles may occur in the bent portion, and the quality may be poor. In particular, when a composite phase difference plate is formed of a film, the occurrence is remarkable.

An object of the present invention is to provide a composite phase difference plate, an optical layered body including the composite phase difference plate, and an image display device including the optical layered body, wherein the composite phase difference plate is transported, wound, or the like. In the case where the composite phase difference plate is bent due to contact with the roll member or the surface of the image display panel having the bent portion, the occurrence of wrinkles in the bent portion is suppressed.

The present invention provides a composite phase difference plate, an optical laminate, and an image display device shown below.

[1] A composite phase difference plate comprising a first retardation layer, a second retardation layer, and a first subsequent layer following the first retardation layer and the second retardation layer, wherein a puncture slope per unit thickness It is 6 kg/mm ² to 15 kg/mm ² .

[2] The composite phase difference plate according to [1], wherein the first adhesive layer is a cured layer of an active energy ray-curable adhesive.

[3] The composite phase difference plate according to [1], wherein the first retardation layer is a 1/2 wavelength layer, and the second retardation layer is a 1/4 wavelength layer.

[4] The composite phase difference plate according to [1], wherein the first retardation layer is a 1/2 wavelength layer or a 1/4 wavelength layer, and the second retardation layer is an optical compensation layer.

[5] The composite phase difference plate according to any one of [1] to [4] wherein at least one of the first retardation layer and the second retardation layer includes a phase difference display layer belonging to the liquid crystal layer.

[6] The composite phase difference plate according to any one of [1] to [5], wherein the thickness is from 2 μm to 50 μm.

[7] An optical layered body comprising: a polarizing plate and a composite phase difference plate according to any one of [1] to [6], wherein the composite phase difference plate has a first phase difference The layer is located on the side of the polarizing plate side to laminate.

[8] The optical layered body according to [7], which is a circularly polarizing plate.

[9] The optical laminate according to [7] or [8], further comprising a second adhesive layer which is followed by the polarizing plate and the composite retardation film.

[10] The optical layered product according to [9], wherein the second adhesive layer is a cured layer of an active energy ray-curable adhesive.

[11] An image display device comprising an image display panel, and an optical layered body according to any one of [7] to [10], which is disposed on the visual recognition side of the image display panel.

[12] The image display device according to [11], wherein the optical layering system is disposed such that the polarizing plate is located on a side of the viewing side.

[13] The image display device according to [12], which is an organic electroluminescence display device.

According to the composite phase difference plate of the present invention, in the step of being conveyed, wound, or the like, the composite phase is caused by contact with the roller-shaped member or by the surface of the image display device panel having the curved portion. When the difference plate is bent, the occurrence of wrinkles in the bent portion is also suppressed.

1‧‧‧1st phase difference layer

2‧‧‧2nd phase difference layer

4‧‧‧1st layer

5‧‧‧Composite phase difference plate

10‧‧‧1st phase difference layer

11‧‧‧1st substrate layer

12‧‧‧1st alignment layer

13‧‧‧1st phase difference presentation layer

20‧‧‧2nd phase difference layer

21‧‧‧2nd substrate layer

22‧‧‧2nd alignment layer

23‧‧‧2nd phase difference presentation layer

30‧‧‧ phase difference layer

31‧‧‧Substrate layer

32‧‧‧Alignment layer

33‧‧‧ phase difference presentation layer

40‧‧‧1st layer

50‧‧‧Laminated body (composite phase difference plate)

Fig. 1 is a schematic cross-sectional view showing an example of a composite phase difference plate of the present invention.

Fig. 2 is a schematic cross-sectional view showing an example of a phase difference layer having a liquid crystal layer as a phase difference display layer.

Fig. 3 (A) to (C) are schematic cross-sectional views showing an example of each manufacturing step in the method for producing a composite phase difference plate of the present invention.

Hereinafter, the composite retardation film and the optical laminate of the present invention will be described with reference to the drawings.

[Composite phase difference plate]

Fig. 1 is a schematic cross-sectional view showing an example of a composite phase difference plate of the present invention. As shown in FIG. 1, the composite phase difference plate 5 includes a first retardation layer 1 and a second retardation layer 2, and a first subsequent layer 4 following the first retardation layer 1 and the second retardation layer 2. The puncture slope per unit film thickness of the composite phase difference plate 5 is from 6 kg/mm ² to 15 kg/mm ² , preferably from 6 kg/mm ² to 12 kg/mm ² , more preferably from 6.5 kg/mm ² to 10 kg/mm ^{2 .} More preferably, it is 7 kg/mm ² to 10 kg/mm ² , particularly preferably 8 kg/mm ² to 10 kg/mm ² . When the puncture gradient per unit thickness is 6 kg/mm ² or more, wrinkles can be suppressed even when the composite retardation film 5 or the optical laminate including the composite retardation film 5 is bent. In addition, when the puncture gradient per unit thickness of the composite phase difference plate 5 is more than 15 kg/mm ² , the composite phase difference plate 5 or the optical laminate including the composite phase difference plate 5 is processed during cutting or the like. At the ends, it is easy to produce fine cracks.

The puncture slope of the composite phase difference plate indicates the strength at which the composite phase difference plate is vertically pierced by the puncture aid and is cracked when the composite phase difference plate is broken. The puncture slope can be calculated from the puncture strength, and the puncture strength can be measured, for example, using a small table tester [product name "EZ Test" of Shimadzu Corporation).

The measurement of the puncture strength was carried out by sandwiching a composite phase difference plate between two sample blocks having a circular hole having a diameter of 15 mm or less which can be used for puncture assistance. The puncture aid is a cylindrical rod, and preferably has a spherical or hemispherical puncture needle at a distal end that is in contact with the composite phase difference plate. The diameter of the spherical portion or the hemispherical portion of the front end is preferably 0.5 mm. Above, 5mm the following. Further, the radius of curvature is preferably greater than 0R and less than 0.7R. The puncture-assisted puncture speed is preferably 0.05 cm/sec or more and 0.5 cm/sec or less.

The puncture strength was measured by fixing the test piece to an auxiliary tool, puncture from the normal direction of the main surface of the composite phase difference plate, and measuring the strength when a portion was cleaved. The obtained puncture strength A (kg), puncture depth B (mm) after splitting, and composite retardation plate thickness d (mm) are given by the following formula: E=A/(B×d)

The puncture slope E (kg/mm ² ) per unit film thickness was calculated. Further, the average value of the puncture slope E of the five or more composite retardation plates produced under the same conditions was used as the puncture slope of the composite phase difference plate.

In the composite phase difference plate 5, for example, in the step of being conveyed, wound, or the like, the composite phase difference plate 5 or the optical layered body including the composite phase difference plate 5, and the conveyance roller or the winding roller are used. When the roll-shaped member is in contact with the surface of the image display panel having the bent portion or the like, and the composite phase difference plate is bent, the composite phase difference plate 5 of the present invention can be suppressed to the first phase. The poor layer 1 and/or the second retardation layer 2 are wrinkled.

The thickness of the composite phase difference plate 5 is preferably from 1 μm to 100 μm, more preferably from 1 μm to 50 μm, still more preferably from 2 μm to 50 μm, from the viewpoint of thinning.

<First retardation layer and second retardation layer>

The first retardation layer 1 and the second retardation layer 2 are not particularly limited as long as they contain at least one predetermined phase difference, and may be, for example, a 1/2 wavelength layer or a 1/4 wavelength. The optical compensation layer such as a layer or a positive C plate (+C plate) may be a retardation layer having a reverse wavelength dispersion. In particular, when it is a retardation layer having a reverse wavelength dispersion, since light penetration can be suppressed at any wavelength, it can be effectively used as an optical laminate having antireflection properties. The first retardation layer 1 and the second retardation layer 2 may have at least one phase difference display layer, and may be formed of only a phase difference display layer, or may have other layers simultaneously with the phase difference display layer. By. The other layer may, for example, be a substrate layer, an alignment film layer, a protective layer or the like. Also, other layers do not affect the value of the phase difference.

The phase difference display layer may, for example, be a layer formed using a liquid crystal compound (hereinafter referred to as "liquid crystal layer") or a stretched film. The first retardation layer 1 and the second retardation layer 2 are preferably formed of a liquid crystal layer from the viewpoint of reducing the thickness of the composite retardation film, and it is more preferable that both of the retardation layers 1 and the second retardation layer 2 are liquid crystal layers. The phase difference revealing layer of the liquid crystal layer is generally easier to be thinned than the phase difference exhibiting layer of the stretched film. The thickness of the first retardation layer 1 and the second retardation layer 2 is preferably from 0.5 μm to 10 μm, and more preferably from 0.5 μm to 5 μm. When the first retardation layer 1 and the second retardation layer 2 each include a layer other than the phase difference display layer (base material layer, alignment film layer, protective layer, etc.), the overall thickness is preferably 0.5 μm to 300 μm. Preferably, it is from 0.5 μm to 150 μm.

The thinner the thickness of the first retardation layer 1 and the second retardation layer 2, the more easily the bent portion of the composite retardation film is in the first retardation layer 1 and the second retardation layer when the composite retardation film is bent. In the case of the composite retardation film of the present invention, even if the first retardation layer 1 and the second retardation layer 2 are thinned to 5 μm or less, the occurrence of wrinkles can be suppressed.

The combination of the first retardation layer 1 and the second retardation layer 2 in the composite retardation film of the present invention may be, for example, i) a combination of a 1/2 wavelength layer and a 1/4 wavelength layer, ii) 1/2 The combination of the wavelength layer and the optical compensation layer, iii) the combination of the 1/4 wavelength layer and the optical compensation layer, iv) the combination of the inverse dispersion 1/4 wavelength layer and the optical compensation layer, and the like.

The 1/2 wavelength layer has a function of changing the direction of the linearly polarized light (polarized azimuth) by giving a phase difference of π (= λ/2) in the direction of the electric field vibration (polarizing surface) of the incident light. Moreover, when the light of the circularly polarized light is incident, the rotation direction of the circularly polarized light can be reversed.

The 1/2 wavelength layer is a layer in which the retardation value Re(λ) in the in-plane of the specific wavelength λ nm satisfies Re(λ)=λ/2. Re(λ)=λ/2 may be achieved at any wavelength in the visible light region, but it is preferably achieved at a wavelength of 550 nm. The retardation value Re (550) in the plane of the wavelength of 550 nm preferably satisfies 210 nm ≦ Re (550) ≦ 300 nm. Further, it is more preferable to satisfy 220 nm ≦ Re (550) ≦ 290 nm.

The retardation value Rth (550) in the thickness direction of the 1/2 wavelength layer measured at a wavelength of 550 nm is preferably -150 to 150 nm, more preferably -100 to 100 nm.

The 1/4 wavelength layer gives a phase difference of π/2 (= λ / 4) in the direction of the electric field vibration (polarizing surface) of the incident light, and converts linearly polarized light of a specific wavelength into circularly polarized light (or polarized light) The function of converting to linear polarization).

The 1/4 wavelength layer is a layer in which the retardation value Re(λ) in the in-plane of the specific wavelength λnm satisfies Re(λ)=λ/4, as long as it is achieved at any wavelength of the visible light region, but preferably at the wavelength. 550nm reached. The retardation value Re (550) in a plane of a wavelength of 550 nm preferably satisfies 100 nm ≦ Re (550) ≦ 160 nm. Further, it is more preferable to satisfy 110 nm ≦ Re (550) ≦ 150 nm.

The retardation value Rth (550) in the thickness direction of the λ/4 wavelength layer measured at a wavelength of 550 nm is preferably -120 to 120 nm, more preferably -80 to 80 nm.

The optical compensation layer may, for example, be a positive A plate (+A plate) or a positive C plate. The positive A plate system has a refractive index of Nx in the in-plane direction, a refractive index in the fast axis direction of the surface is Ny, and a refractive index in the thickness direction is Nz, and satisfies the relationship of Nx>Ny. The positive A plate preferably satisfies the relationship of Nx>Ny≧Nz. Moreover, the positive A plate can also function as a 1/4 wavelength layer. The positive C plate system satisfies the relationship of Nz>Nx≧Ny.

The reverse wavelength dispersion refers to an optical characteristic in which the phase difference value of the liquid crystal alignment in the liquid crystal alignment in the short-wavelength phase alignment is small, and the phase difference is small in the liquid crystal alignment. It is preferable to satisfy the following formula (a): Re (450) ≦Re(550)≦Re(650) (a)

Further, Re (λ) represents an in-plane phase difference value with respect to light of a wavelength λ nm.

The optical characteristics of the phase difference layer can be adjusted by the alignment state of the liquid crystal compound constituting the phase difference display layer or the stretching method of the stretched film constituting the phase difference display layer. By appropriately adjusting the optical characteristics of the phase difference layer, the composite phase difference plate 5 and the polarizing plate are laminated to obtain an optical layered body having antireflection properties. In the present invention, the optical laminated layer laminated polarizing plate and the composite phase difference plate 5 are formed, and the composite phase difference plate 5 is laminated with the first retardation layer 1 facing the polarizing plate side. Even if the same composite phase difference plate 5 is used, if the layers of the composite phase difference plate 5 face oppositely, the optical characteristics of the optical laminate generally differ.

(phase difference display layer formed by the liquid crystal layer)

The case where the phase difference presentation layer is a liquid crystal layer will be described below. Fig. 2 is a schematic cross-sectional view showing an example of a phase difference layer including a phase difference display layer belonging to a liquid crystal layer and other layers. As shown in FIG. 2, the phase difference layer 30 is formed by sequentially laminating a base material layer 31, an alignment layer 32, and a phase difference display layer 33 belonging to the liquid crystal layer. The phase difference layer is not limited to the phase difference layer 30 shown in FIG. 2 as long as it includes the phase difference display layer 33 belonging to the liquid crystal layer, and only the base layer 31 may be peeled off by the phase difference plate 30. The alignment layer 32 and the phase difference display layer 33 are formed, and only the phase difference display layer 33 belonging to the liquid crystal layer of the base layer 31 and the alignment layer 32 may be peeled off from the phase difference plate 30. From the viewpoint of film formation, the retardation layer is preferably formed by peeling off the base material layer 31, and more preferably consisting only of the phase difference display layer 33 belonging to the liquid crystal layer. The base material layer 31 has a function of a support layer which supports the alignment layer 32 formed on the base material layer 31 and the phase difference display layer 33 belonging to the liquid crystal layer. The base material layer 31 is preferably a film formed of a resin material.

For the resin material, for example, a resin material excellent in transparency, mechanical strength, thermal stability, and stretchability can be used. Specifically, for example, a polyolefin resin such as polyethylene or polypropylene; a cyclic polyolefin resin such as a norbornene-based polymer; and a polycondensation such as polyethylene terephthalate or polyethylene naphthalate; (ester) resin; (meth)acrylic resin such as (meth)acrylic acid or poly(methyl) acrylate; cellulose ester such as cellulose triacetate, cellulose diacetate, and cellulose acetate propionate Resin; vinyl alcohol resin such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resin; polystyrene resin; polyacrylate resin; polyfluorene resin; polyether oxime resin; Polyimide resin; polyether ketone resin; polyphenylene sulfide resin; polyphenylene ether resin, and mixtures, copolymers and the like. Among these resins, any of a cyclic polyolefin resin, a polyester resin, a cellulose ester resin, and a (meth)acrylic resin or a mixture thereof is preferably used. Moreover, the above "(meth)acrylic acid" means "at least one of acrylic acid and methacrylic acid".

The base material layer 31 may be one type of the above resins or a single layer of two or more types, or may have a multilayer structure of two or more layers. When having a multilayer construction, the resins constituting each layer may be the same or different.

Any resin may be added to the resin material constituting the resin film. The additives may, for example, be ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-colorants, flame retardants, nucleating agents, antistatic agents, pigments, and color formers.

The thickness of the base material layer 31 is not particularly limited, but is generally from the viewpoint of workability such as strength and workability, and is preferably from 5 to 200 μm, more preferably from 10 to 200 μm, still more preferably from 10 to 150 μm.

In order to improve the adhesion between the base layer 31 and the alignment layer 32, at least the surface of the base layer 31 on the side of the alignment layer 32 may be subjected to plasma treatment, flame treatment or the like, or a primer layer may be formed. Moreover, when the base material layer 31 or the peeling base material layer 31 and the alignment layer 32 are peeled off to form a phase difference layer, it can be easily peeled off by adjusting the adhesive force of a peeling interface.

The alignment layer 32 has an alignment control force for aligning the liquid crystal contained in the phase difference display layer 33 belonging to the liquid crystal layer formed on the alignment layer 32 in the desired direction. The alignment layer 32 may be, for example, an alignment polymer layer formed by an alignment polymer, a photo-alignment polymer layer formed by a photo-alignment polymer, or a groove alignment having a concave-convex pattern or a plurality of grooves (grooves) on the surface of the layer. Floor. The thickness of the alignment layer 32 is usually from 0.01 to 10 μm, preferably from 0.01 to 5 μm.

The alignment polymer layer can be formed by applying a composition of the alignment polymer dissolved in a solvent to the substrate layer 31 to remove the solvent, and if necessary, performing a rubbing treatment. In this case, the alignment control force can be arbitrarily adjusted by the surface state or the rubbing condition of the alignment polymer in the alignment polymer layer formed of the alignment polymer.

The photo-alignment polymer layer can be formed by applying a composition containing a photoreactive group-containing polymer or a monomer and a solvent to the substrate layer 31 by irradiation of polarized light. In this case, the alignment control force can be arbitrarily adjusted in the photo-alignment polymer layer by the polarized light irradiation condition of the photo-alignment polymer or the like.

The groove alignment layer can be formed, for example, by a method of exposing, developing, or the like to form a concavo-convex pattern by exposing, developing, or the like through an exposure mask having a slit having a pattern shape on the surface of the photosensitive polyimide film; a method in which a groove having a groove on the surface forms an uncured layer of an active energy ray-curable resin, a layer is transferred to the substrate layer 31 for hardening, and an active energy ray-curable resin is formed on the substrate layer 31. The uncured layer is a method in which the layer is formed into a concave-convex shape by pressing a drum-shaped disk having irregularities or the like.

The phase difference display layer 33 which is a liquid crystal layer is not particularly limited as long as it can impart a predetermined phase difference to light, and may have, for example, a phase difference display layer for a 1/2 wavelength layer and a 1/4 wavelength layer. The phase difference display layer, the phase difference display layer for the optical compensation layer such as the positive C plate, and the phase difference display layer for the reverse wavelength dispersion 1/4 wavelength layer are used.

The phase difference display layer 33 belonging to the liquid crystal layer can be formed using a well-known liquid crystal compound. The type of the liquid crystal compound is not particularly limited, and a rod-like liquid crystal compound, a discotic liquid crystal compound, and a mixture thereof can be used. Further, the liquid crystal compound may be a polymer liquid crystal compound, may be a polymerizable liquid crystal compound, or may be a mixture thereof. For example, Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Japanese Laid-Open Patent Publication No. 2010-270108, Japanese Laid-Open Patent Publication No. 2011-6360, Japanese Laid-Open Patent Publication No. 2011-207765, Japanese Laid-Open Publication No. 2016-81035, International Publication No. 2017/043438, and Japanese Special Table 2011- Liquid crystal compound described in Japanese Patent Publication No. 207765.

For example, when a polymerizable liquid crystal compound is used, a composition containing a polymerizable liquid crystal compound is applied onto the alignment layer 32 to form a coating film, and the coating film is cured to form a phase difference display layer 33. The thickness of the phase difference display layer 33 is preferably from 0.5 μm to 10 μm, more preferably from 0.5 to 5 μm.

The composition containing a polymerizable liquid crystal compound may contain, in addition to the liquid crystal compound, a polymerization initiator, a polymerizable monomer, a surfactant, a solvent, an adhesion improver, a plasticizer, an alignment agent, and the like. The coating method of the composition containing a polymerizable liquid crystal compound is a well-known method, such as a die coating method. The curing method of the composition containing the polymerizable compound may, for example, be a known method such as irradiation with an active energy ray (e.g., ultraviolet ray).

(a phase difference plate having a stretched film as a phase difference display layer)

The case where the phase difference presentation layer is a stretched film will be described below. Stretched films are usually obtained by stretching a substrate. A method of stretching a substrate, for example, preparing a roll (rolled body) in which a substrate is wound around a roll, continuously unwinding the substrate from the wound body, and conveying the unwound substrate to a heating furnace. The set temperature of the heating furnace is in the range of the glass transition temperature (°C) to the [glass transition temperature +100] (°C) of the substrate, preferably, near the glass transition temperature (°C) to [glass transition temperature +50]. The range of (°C). In the heating furnace, when stretching in the direction of the substrate or in the direction perpendicular to the direction of progress, the conveyance direction or the tension is adjusted to be inclined at an arbitrary angle to perform the uniaxial or biaxial hot stretching treatment. The stretching ratio is usually from 1.1 to 6 times, preferably from 1.1 to 3.5 times.

Further, the method of stretching in the oblique direction is not particularly limited as long as the alignment axis can be continuously inclined to a desired angle, and a well-known stretching method can be used. The method described in the above-mentioned Japanese Patent Laid-Open Publication No. SHO-50-84382 or JP-A No. 2-113920. When the phase difference property of the film is imparted by stretching, the thickness after stretching is determined depending on the thickness before stretching and the stretching ratio.

The aforementioned substrate is usually a transparent substrate. The transparent substrate refers to a substrate having transparency of light, particularly visible light, and the term "transparency" refers to a property of a light transmittance of 80% or more with respect to a wavelength of 380 to 780 nm. Specific examples of the transparent substrate include a light-transmitting resin substrate. The resin constituting the light-transmitting resin substrate may, for example, be a polyolefin such as polyethylene or polypropylene; a cyclic polyolefin resin such as a norbornene-based polymer; polyvinyl alcohol; polyethylene terephthalate; Acrylate; polyacrylate; cellulose triacetate; cellulose acetate such as cellulose diacetate, cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polyfluorene; polyether oxime; Polyether ketone; polyphenylene sulfide and polyphenylene ether. From the viewpoint of easy availability and transparency, polyethylene terephthalate, polymethacrylate, cellulose ester, cyclic olefin resin or polycarbonate is preferred.

Any one or all of the hydroxyl groups contained in the cellulose ester cellulose can be easily obtained from the market by esterification. Further, cellulose ester substrates are also readily available from the market. The commercially available cellulose ester substrate may, for example, be "Fujitac (registered trademark) film" (Fuji film); "KC8UX2M", "KC8UY", and "KC4UY" (Konica Minolta Co., Ltd.).

Polymethacrylates and polyacrylates (hereinafter also referred to as polymethacrylates and polyacrylates collectively referred to as (meth)acrylic resins) are readily available from the market.

The (meth)acrylic resin may, for example, be a homopolymer of an alkyl methacrylate or an alkyl acrylate, a copolymer of an alkyl methacrylate or an alkyl acrylate, or the like. Specific examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, and propyl methacrylate. Further, the alkyl acrylate may, for example, be methyl acrylate or ethyl acrylate. , propyl acrylate and the like. As the (meth)acrylic resin, a commercially available (meth)acrylic resin can be used. A (meth)acrylic resin may also be referred to as an impact-resistant (meth)acrylic resin.

In order to further increase the mechanical strength, it is also preferred that the (meth)acrylic resin contains rubber particles. The rubber particles are preferably acrylic. Here, the acrylic rubber particles are obtained by polymerizing an acrylic monomer mainly composed of an alkyl acrylate such as butyl acrylate or 2-ethylhexyl acrylate in the presence of a polyfunctional monomer. Particles with rubber elasticity. The acrylic rubber particles may be formed of a single layer of such rubber-elastic particles, or may be a multilayer structure having at least one rubber elastic layer. The acrylic rubber particles having a multilayer structure may, for example, be coated with a rubbery elastic particle as a core, and coated with a hard alkyl methacrylate polymer around the hardened alkyl methacrylate polymer; The polymer is a core surrounded by the above-mentioned rubber-elastic acrylic polymer; or the rubber-elastic acrylic polymer is coated around the hard core, and the surrounding is made of hard methacrylic acid. Alkyl ester-based polymer coated or the like. The particles formed of the elastic layer have an average diameter of usually about 50 to 400 nm.

The content of the rubber particles in the (meth)acrylic resin is usually about 5 to 50 parts by mass per 100 parts by mass of the (meth)acrylic resin. Since the (meth)acrylic resin and the acrylic rubber particle are sold in such a state of being mixed, the commercially available product can be used. An example of a commercially available product of a (meth)acrylic resin containing acrylic rubber particles is "HT55X" and "TECHNOLLOY S001" sold by Sumitomo Chemical Co., Ltd. "TECHNOLLOY S001" is sold as a film.

A cyclic olefin resin can be easily obtained from the market. The commercially available cyclic olefin resin is, for example, "Topas" (registered trademark) [Ticona Co., Ltd.], "ARTON" (registered trademark) [JSR Co., Ltd.], "ZEONOR" (registered trademark) [Japan ZEON] Co., Ltd.], "ZEONEX" (registered trademark) [Japan ZEON Co., Ltd.] and "Apel" (registered trademark) [Mitsui Chemical Co., Ltd.]. Such a cyclic olefin-based resin can be formed into a film by a known method such as a solvent casting method or a melt extrusion method. Further, a commercially available cyclic olefin resin substrate can also be used. The commercially available cyclic olefin resin substrate may, for example, be "ESSINA" (registered trademark) [Ji Shui Chemical Industry Co., Ltd.], "SCA40" (registered trademark) [Ji Shui Chemical Industry Co., Ltd.], "ZEONOR FILM" ( Registered trademark) [OPTES Co., Ltd.] and "ARTONFILM" (registered trademark) [JSR Co., Ltd.].

When the cyclic olefin resin is a copolymer of a cyclic olefin and a chain olefin or an aromatic compound having a vinyl group, the content ratio of the structural unit derived from the cyclic olefin is usually based on the total structural unit of the copolymer. 50 mol% or less, preferably 15 to 50 mol%. The chain olefin may, for example, be ethylene or propylene, and the aromatic compound having a vinyl group may, for example, be styrene, α-methylstyrene or alkyl-substituted styrene. When the cyclic olefin resin is a ternary copolymer of a cyclic olefin, a chain olefin, and an aromatic compound having a vinyl group, the content ratio of the structural unit derived from the chain olefin is relative to the total structural unit of the copolymer. It is usually from 5 to 80 mol%, and the content ratio of the structural unit derived from the aromatic compound having a vinyl group is usually from 5 to 80 mol% with respect to the total structural unit of the copolymer. Such a terpolymer can be used in the manufacture, and the use amount of a less expensive cyclic olefin can be used, which is an advantage.

<1st layer>

The first rectifying layer 4 is not particularly limited as long as the puncture gradient per unit thickness of the composite retardation film 5 is 6 kg/mm ² to 15 kg/mm ² , and may be, for example, an adhesive or a water-based adhesive. An active energy ray-curable adhesive and a combination thereof. Among them, the first adhesive layer 5 which is an active energy ray-curable adhesive can easily obtain the composite retardation film 5 having a puncture gradient of 6 kg/mm ² to 15 kg/mm ² . The first subsequent layer 4 preferably has a thickness of from 0.1 μm to 50 μm, more preferably from 0.1 μm to 10 μm, still more preferably from 0.5 μm to 5 μm. In the present specification, the term "first adhesive layer" includes not only an adhesive layer composed of an adhesive but also an adhesive layer composed of an adhesive.

The adhesive is generally preferably an acrylic adhesive containing an acrylic resin having a glass transition temperature Tg of 0 ° C or less and a crosslinking agent, and the acrylic resin is mainly composed of (meth) acrylate and contains a small amount. The acrylic polymer mixture having a functional group (meth)acrylic monomer is subjected to radical polymerization in the presence of a polymerization initiator.

The acrylic resin constituting the acrylic pressure-sensitive adhesive has a weight average molecular weight Mw in terms of standard styrene obtained by gel permeation chromatography (GPC), preferably in the range of 1,000,000 to 2,000,000. When the amount average molecular weight is 1,000,000 or more, the adhesion under high temperature and high humidity is increased, and the possibility of floating or peeling between the glass substrate constituting the liquid crystal cell and the adhesive layer tends to decrease, and Heavy work has a tendency to improve, so it is better. In addition, when the weight average molecular weight of the acrylic resin is 2,000,000 or less, even if the size of the polarizing plate changes, the adhesive layer changes in accordance with the dimensional change, and the light leakage or color deviation of the display tends to be suppressed. Therefore, it is better. Further, the molecular weight distribution represented by the ratio Mw/Mn of the weight average molecular weight Mw to the number average molecular weight Mn is preferably in the range of 3 to 7.

The acrylic resin contained in the acrylic pressure-sensitive adhesive may be composed only of the above-mentioned higher molecular weight, or may be composed of a mixture with a different acrylic resin. For example, the constituent unit of the (meth) acrylate represented by the above formula (I) is a main component, and the weight average molecular weight is in the range of 50,000 to 300,000.

The acrylic resin thus obtained is formulated with a crosslinking agent as an adhesive. The crosslinking agent is a compound having at least two functional groups capable of crosslinking reaction with a structural unit derived from a monomer having a polar functional group in an acrylic resin, for example, an isocyanate compound, an epoxy compound, or a metal. A chelate compound, an aziridine compound or the like.

The method of forming the adhesive layer on the optical film may be, for example, a method of applying the above-mentioned adhesive composition to form an adhesive layer using a release film as a substrate, and transferring the obtained adhesive layer to the surface of the optical film. Method; a method in which the above adhesive layer is directly coated on the surface of the optical film to form an adhesive layer. Further, after the adhesive layer is formed on one of the release films, another release film may be bonded to the adhesive layer to form a double-sided separator type adhesive sheet. Such a double-sided separator type adhesive sheet can be peeled off from the one-side release film and attached to the optical film as necessary. Commercially available products of the double-sided separator type adhesive sheet are, for example, a carrier-free adhesive film or a carrier-free adhesive sheet sold by Lintec Co., Ltd. or Nitto Denko Corporation.

For the water-based adhesive, for example, a polyvinyl alcohol-based resin or an amine ester resin is used as a main component, and in order to improve adhesion, a composition having a crosslinking agent such as an isocyanate compound or an epoxy compound or a curable compound is generally used.

When a polyvinyl alcohol-based resin is used as a main component of the water-based adhesive, in addition to the partially saponified polyvinyl alcohol and the fully saponified polyvinyl alcohol, a carboxyl-modified polyvinyl alcohol or an ethylene-ethyl ruthenium-modified polyethylene may be used. Modified polyvinyl alcohol resin such as alcohol, hydroxymethyl modified polyvinyl alcohol, and amine modified polyvinyl alcohol. The aqueous solution of the polyvinyl alcohol-based resin is used as a water-based adhesive, and the concentration of the polyvinyl alcohol resin in the aqueous adhesive is usually 1 to 10 parts by mass, preferably 1 to 5 parts by mass based on 100 parts by mass of water. Share.

The water-based adhesive agent which consists of an aqueous solution of a polyvinyl-alcohol-type resin can be adjusted as a hardening compound, such as a polyhydric aldehyde, a water-soluble epoxy resin, a melamine-type compound, a zirconia-type compound, and a zinc compound, in order to improve adhesiveness. Examples of the water-soluble epoxy resin include, for example, a polyamidamine polyamine obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarbonic acid such as adipic acid to cause epichlorohydrin. The water-soluble polyamine epoxy resin obtained by the reaction. Commercial products of such polyamine epoxy resins include "Sumirez Resin 650" and "Sumirez Resin 675" sold by Sumitomo Chemtex Co., Ltd., and "WS-525" sold by Japan PMC Co., Ltd., and the like. When the water-soluble epoxy resin is blended, the amount thereof is usually from about 1 to 100 parts by mass, preferably from 1 to 50 parts by mass, per 100 parts by mass of the polyvinyl alcohol-based resin.

Further, when an amine ester resin is used as a main component of a water-based adhesive, a polyester-based ionic polymer-type amine ester resin is effective as a main component of a water-based adhesive. Here, the polyester-based ionic polymer-type amine ester resin refers to an amine ester resin having a polyester skeleton, and a small amount of an ionic component (hydrophilic component) is introduced therein. Since the polyester-based ionic polymer type amine ester resin is directly emulsified in water to form a latex without using an emulsifier, it can be used as an aqueous adhesive. When a polyester-based ionic polymer type amine ester resin is used, it is effective to use a water-soluble epoxy compound as a crosslinking agent. The polyester-based ionic polymer-type urethane resin is used as an adhesive for a polarizing plate, for example, in JP-A-2005-70140 or JP-A-2005-208456.

The components constituting the water-based adhesive are usually used in a state of being dissolved in water. The adhesive layer can be obtained by applying a water-based adhesive to a suitable substrate and drying it. The component that does not dissolve in water may be in a state of being dispersed in the system.

The method of forming the above-mentioned adhesive layer on the present optical film may, for example, be a method in which the above-mentioned adhesive composition is directly applied to the surface of the present optical film to form an adhesive layer.

Further, for example, after the obtained water-based adhesive is injected between the polarizing plate and the present optical film, water can be evaporated by heating and the crosslinking reaction can be carried out to provide sufficient adhesion between the two.

The active energy ray-curable adhesive is cured by irradiation with an active energy ray, and is not particularly limited as long as a composite phase difference plate 5 having a puncture gradient of 6 kg/mm ² to 15 kg/mm ² can be obtained. For example, a cationically polymerizable active energy ray-curable adhesive containing an epoxy compound and a cationic polymerization initiator; and a radical polymerizable active energy ray-curable type containing an acrylic hardening component and a radical polymerization initiator A curing agent containing a curing component such as an epoxy compound and a curing component such as an acrylic compound, and a curing component such as a radical polymerization property, and a radical polymerization initiator and a radical polymerization initiator An active energy ray-curable adhesive; and an electron beam-curable adhesive which is cured by irradiating an electron beam to an active energy ray-curable adhesive which does not contain an initiator. A radical polymerizable active energy ray-curable adhesive containing an acrylic curing component and a radical polymerization initiator is preferred. Further, a cationically polymerizable active energy ray-curable adhesive containing an epoxy compound and a radical polymerization initiator, which is substantially solvent-free, is preferred.

Selecting an epoxy compound which is cationically polymerizable, which is liquid at room temperature, has moderate fluidity even in the absence of a solvent, and can impart appropriate hardening strength, and is formulated with a suitable cationic polymerization initiator The active energy ray-curable adhesive can omit the drying equipment necessary for the steps following the first retardation layer and the second retardation layer in the manufacturing apparatus of the composite retardation film. Moreover, by irradiating an appropriate active energy ray, the hardening speed can be promoted and the production speed can be increased.

The epoxy compound used in such an adhesive may be a glycidyl etherate of an aromatic compound or a chain compound having a hydroxyl group; a glycidyl etherate of a compound having an amine group; a chain compound having a CC double bond; An epoxide; an alicyclic epoxy compound having a glycidoxy group or an epoxy group bonded to a saturated carbocyclic ring directly or through an alkyl group, or an epoxy group directly bonded to a saturated carbocyclic ring. These epoxy compounds may be used singly or in combination of plural kinds. Among them, the alicyclic epoxy compound is preferably used because it has excellent cationic polymerizability.

A glycidyl etherate having an aromatic compound or a chain compound of a hydroxyl group, for example, a method of adding and condensing epichlorohydrin under alkaline conditions by using a hydroxyl group of the aromatic compound or the chain compound To manufacture. Such a glycidyl ether compound having a hydroxyl group-containing aromatic compound or a chain compound, comprising a bisphenol-based diglycidyl ether, a polyaromatic ring type epoxy resin, an alkylene glycol or a polyalkylene glycol Glycidyl ether and the like.

Examples of the bisphenol-based diglycidyl ethers include epoxidized ethers of bisphenol A and oligomers thereof, epoxidized ethers of bisphenol F and oligomers thereof, 3, 3', 5, 5 '-Tetramethyl-4,4'-biphenol epoximide and its oligomers.

The polyaromatic epoxy resin may, for example, be a glycidyl ether of a novolac resin, a glycidyl ether of a cresol novolak resin, a glycidyl ether of a phenol aralkyl resin, or a naphthol aralkyl group. A glycidyl etherate of a resin, a glycidyl ether of a phenol dicyclopentadiene resin, or the like. Further, the trisphenol-containing epoxidized ethers and oligomers thereof are also polyaromatic ring-type epoxy resins.

The diglycidyl ether of an alkylene glycol or a polyalkylene glycol may, for example, be a glycidyl etherate of ethylene glycol, a glycidyl ether of diethylene glycol, or a ring of 1,4-butanediol. An oxypropyl ether compound, a propylene oxide ether of 1,6-hexanediol, or the like.

The glycidylamino group of the compound having an amine group can be produced, for example, by subjecting an amine group of the compound to epichlorofluoropropane addition condensation under basic conditions. A compound having an amine group may also have a hydroxyl group. The glycidylamine of such a compound having an amine group comprises a glycidylamine of 1,3-phenylenediamine and an oligomer thereof, and a propylene oxide of 1,4-phenylenediamine Aminoamines and oligomers thereof, glycidyl amination of 3-aminophenols and glycidyl ethers and oligomers thereof, glycidyl amination of 4-aminophenols and rings Oxypropyl ethers and oligomers thereof.

An epoxide having a chain compound of a C-C double bond can be produced by a method in which a C-C double bond of the chain compound is epoxidized under a basic condition using a peroxide. The chain compound having a C-C double bond includes butadiene, polybutadiene, isoprene, pentadiene, hexadiene, and the like. Further, an anthracene having a double bond can also be used as an epoxidation raw material, and an acyclic monoterpene having a linalool or the like. The peroxide used in the epoxidation may be, for example, hydrogen peroxide, peracetic acid, tributyl peroxide or the like.

An alicyclic epoxy compound having a glycidoxy group or an epoxy group bonded to a saturated carbocyclic ring directly or through an alkyl group, and having an aromatic group having a hydroxyl group as exemplified by the previously disclosed bisphenols A glycidyl ether compound of a hydrogenated polyhydroxy compound obtained by hydrogenating an aromatic ring of a compound, a glycidyl ether compound of a cycloalkane compound having a hydroxyl group, a cycloalkane compound having a vinyl group, or the like.

The epoxy compound described above can be easily obtained as a commercial product, for example, "jER" series sold by Mitsubishi Chemical Corporation under the trade name, "EPICLON" sold by DIC Corporation, and Dongdo. "EPOTOT (registered trademark)" sold by Huacheng Co., Ltd., "ADEKA RESIN (registered trademark)" sold by ADEKA Co., Ltd., "Denacol (registered trademark)" sold by Nagase ChemteX Co., Ltd., "Dow Epoxy" sold by Dow Chemical Co., Ltd., "TEPIC (registered trademark)" sold by Nissan Chemical Industries Co., Ltd., and the like.

On the other hand, an alicyclic epoxy compound having an epoxy group directly bonded to a saturated carbocyclic ring, for example, a base of a non-aromatic cyclic compound having a CC double bond in the ring, may be used in the base. Manufactured by a method of epoxidation using a peroxide under the conditions. The non-aromatic cyclic compound having a CC double bond in the ring may, for example, be a compound having a cyclopentene ring, a compound having a cyclohexene ring, or at least two bonded to a cyclopentene ring or a cyclohexene ring. A polycyclic compound or the like which forms an additional ring by a carbon atom. A non-aromatic cyclic compound having a C-C double bond in the ring may have other C-C double bonds outside the ring. Examples of the non-aromatic cyclic compound having a C-C double bond in the ring include cyclohexene, 4-ethylenecyclohexene, limonene of monocyclic monoterpene, and α-pinene.

An alicyclic epoxy compound having an epoxy group directly bonded to a saturated carbocyclic ring, or a suitable bonding group, wherein at least two of the above-mentioned rings are directly bonded to the epoxy group in the molecule. A compound formed by an alicyclic structure. The bonding group here includes, for example, an ester bond, an ether bond, an alkylene bond or the like.

Specific examples of the cyclic compound in which an epoxy group is directly bonded to a saturated carbon ring are shown below.

3,4-Epoxycyclohexanemethyl 3,4-epoxycyclohexylmethyl, 1,2-epoxy-4-vinylcyclohexane, 1,2-epoxy-4- Epoxyethylcyclohexane, 1,2-epoxy-1-methyl-4-(1-methylepoxyethyl)cyclohexane, 3,4-epoxy (meth)acrylate Addition of cyclohexylmethyl ester, 2,2-bis(hydroxymethyl)-1-butanol to 4-epoxyethyl-1,2-epoxycyclohexane, exoethyl bis ( (3,4-epoxycyclohexane carboxylate), diethylene glycol bis(3,4-epoxycyclohexanecarboxylate), 1,4 -cyclohexanedimethylbis(3,4-epoxycyclohexanecarboxylate), 3,4-epoxycyclohexanecarboxylic acid 3-(3,4-epoxycyclohexylmethoxy) Carbocarbonyl)propyl ester and the like.

The above-described alicyclic epoxy compound in which an epoxy group is directly bonded to an epoxy group can also be easily obtained from the market, and for example, the "CELLOXIDE" series sold by Dicel Co., Ltd., which is separately labeled under the trade name, may be mentioned. And "CYCLOMER M100", "Cyracure UVR" series sold by Dow Chemical Company.

The curable adhesive containing an epoxy compound may further contain an active energy ray-curable compound other than the epoxy compound. Examples of the active energy ray-curable compound other than the epoxy compound include an oxetane compound or an acrylic compound. Among them, since there is a possibility that the curing rate can be promoted in the cationic polymerization, it is preferred to use an oxycyclobutane compound in combination.

The oxycyclobutane compound is a compound having a tetravalent cyclic ether in the molecule, and examples thereof include the following.

1,4-bis[(3-ethyloxycyclobutane-3-yl)methoxymethyl]benzene, 3-ethyl-3-(2-ethylmethyloxymethyl)oxycyclobutane , bis(3-ethyl-3-oxocyclobutanemethyl)ether, 3-ethyl-3-(phenoxymethyl)oxycyclobutane, 3-ethyl-3-(cyclohexyloxy) Shenji) Oxygen cyclobutane, novolac resin Oxycyclobutane, p-xylene dioxycyclobutane, 1,3-bis[(3-ethyloxycyclobutane-3-yl)methoxy] Benzene, etc.

The oxycyclobutane compound can also be easily obtained from the market, and is sold, for example, in the "ARONE OXETANE (registered trademark)" series sold by the East Asia Synthetic Co., Ltd., which is sold under the trade name, and the Ube Hiroshi Co., Ltd. The "ETERNACOLL (registered trademark)" series, etc.

The curable compound containing an epoxy compound or an oxycyclobutane compound is preferably used without being diluted with an organic solvent or the like in order to desolve the binder. Further, the other components constituting the adhesive include a small amount of a cationic polymerization initiator or a sensitizer to be described later, and a compound which is obtained by dissolving or drying the organic solvent, or a compound which is dried, is used alone. Liquid is preferred.

A cationic polymerization initiator is a compound that is irradiated with an active energy ray (e.g., ultraviolet light) to produce a cationic species. As long as the adhesive strength and the curing rate can be imparted to the adhesive containing the cationic polymerization initiator, for example, an aromatic diazonium salt; an sulfonium salt such as an aromatic sulfonium salt or an aromatic sulfonium salt; and an iron-aromatic hydrocarbon (arene) complex and the like. These cationic polymerization initiators may be used singly or in combination of plural kinds.

The aromatic diazonium salt can be exemplified by the following.

Diazobenzene hexafluoroantimonate, diazobenzene hexafluorophosphate, diazobenzene hexafluoroborate.

The aromatic onium salt can be exemplified by the following.

Diphenyl sulfonium tetrakis(pentafluorophenyl)borate, diphenyl sulfonium hexafluorophosphate, diphenyl hydrazine hexafluoroantimonate, bis(4-mercaptophenyl)phosphonium hexafluorophosphate, and the like.

The aromatic onium salt can be exemplified by the following.

Triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, diphenyl(4-phenylthiophenyl)phosphonium hexafluoroantimonate Acid salt, 4,4'-bis(diphenylsulfonyl)diphenyl sulfide dihexafluorophosphate, 4,4'-bis[bis(β-hydroxyethoxyphenyl)sulfonyl] Diphenyl sulfide dihexafluoroantimonate, 4,4'-bis[bis(β-hydroxyethoxyphenyl)sulfonyl]diphenyl sulfide dihexafluorophosphate, 7-[two ( p-Tolyl)sulfonyl]-2-isopropylthioxanthone hexafluoroantimonate, 7-[bis(p-tolyl)sulfonyl]-2-isopropylthioxanthone oxime (pentafluorobenzene) Borate, 4-phenylcarbonyl-4'-diphenylsulfonyldiphenyl sulfide hexafluorophosphate, 4-(p-tert-butylphenylcarbonyl)-4'-diphenyl Sulfonyl diphenyl sulfide hexafluoroantimonate, 4-(p-t-butylphenylcarbonyl)-4'-bis(p-tolyl)sulfonyl-diphenyl sulfide quinone (pentafluoro Phenyl) borate or the like.

The iron-aromatic complex may, for example, be as described below.

Xylene-cyclopentadiene ferrous (II) hexafluoroantimonate, cumene-cyclopentadiene ferrous (II) hexafluorophosphate, xylene-cyclopentadiene ferrous (II) III ( Trifluoromethylsulfonyl) methanide and the like.

Among the cationic polymerization initiators, since the aromatic onium salt has ultraviolet absorption characteristics in a wavelength range of 300 nm or more, it is excellent in curability and can provide an adhesive layer having good mechanical strength and adhesion strength, and thus can be preferably used.

The cationic polymerization initiator can also be easily obtained from the market, and for example, the "KAYARAD (registered trademark)" series sold by Nippon Chemical Co., Ltd., which is sold under the trade name, and the "Cyracure" sold by Dow Chemical Co., Ltd., respectively. UVI" series, photo-acid generator "CPI" series sold by San-Apro Co., Ltd., photoacid generators "TAZ", "BBI" and "DTS" sold by Green Chemical Co., Ltd., limited shares "ADEKA OPTOMER" series sold by the company ADEKA, "RHODORSIL (registered trademark)" sold by RHODIA.

In the active energy ray-curable adhesive, the cationic polymerization initiator is usually formulated in a ratio of 0.5 to 20 parts by mass, preferably 1 to 15 by mass, based on 100 parts by mass of the total amount of the active energy ray-curable adhesive. Share. If the amount is small, the hardening may be insufficient, and the mechanical strength and the subsequent strength of the adhesive layer may be lowered. On the other hand, if the amount is too large, the ionic substance in the adhesive layer is increased to increase the hygroscopicity of the adhesive layer, and the durability of the obtained polarizing plate is lowered.

When the active energy ray-curable adhesive is an electron beam curing type, it is not necessary to particularly contain a photopolymerization initiator in the composition, and when an ultraviolet curing type is used, a photoradical generator is preferably used. The photoradical generating agent may, for example, be a dehydrogenation type photoradical generator and a cracking type photoradical generator.

Examples of the dehydrogenation type photoradical generator include 1-methylnaphthalene, 2-methylnaphthalene, 1-fluoronaphthalene, 1-chloronaphthalene, 2-chloronaphthalene, 1-bromonaphthalene, 2-bromonaphthalene, and 1-iodonaphthalene. , naphthol derivatives such as 2-iodophthalene, 1-naphthol, 2-naphthol, 1-methoxynaphthol, 2-methoxynaphthol, 1,4-dicyanophthol, etc.; , 2-benzoquinone, 9,10-dichloropurine, 9,10-dibromofluorene, 9,10-diphenylhydrazine, 9-cyanoguanidine, 9,10-dicyanoguanidine, 2,6,9 , 10-tetraquinone isomer derivatives; anthracene derivatives; carbazole, 9-methylcarbazole, 9-phenylcarbazole, 9-propan-2-yl-9H-carbazole, 9-propyl-9H -carbazole, 9-vinylcarbazole, 9H-carbazole-9-ethanol, 9-methyl-3-nitro-9H-carbazole, 9-methyl-3,6-dinitro-9H- Carbazole, 9-methyl-3,6-dinitro-9H-carbazole, 9-octylcarbazole, 9-oxazole methanol, 9-carbazole propionic acid, 9-carbazole propionitrile, 9-B 3-,6-dinitro-9H-carbazole, 9-ethyl-3-nitrocarbazole, 9-ethylcarbazole, 9-isopropylcarbazole, 9-(ethoxycarbonylmethyl Carbazole, 9-(morpholinylmethyl)carbazole, 9-acetamidocarbazole, 9-allylcarbazole, 9-benzyl-9H-carbazole, 9-carbazoleacetic acid, 9 -(2-nitrophenyl)carbazole, 9-(4-methoxyphenyl)carbazole, 9-(1- Oxy-2-methyl-propyl)-9H-carbazole, 3-nitrocarbazole, 4-hydroxycarbazole, 3,6-dinitro-9H-carbazole, 3,6-diphenyl Oxazole derivatives such as -9H-carbazole, 2-hydroxycarbazole, 3,6-diethylindenyl-9-ethylcarbazole; diphenyl ketone, 4-phenyldiphenyl ketone, 4,4 '-bis(dimethoxy)diphenyl ketone, 4,4'-bis(dimethylamino)diphenyl ketone, 4,4'-bis(diethylamino)diphenyl ketone, 2-Benzylmercaptobenzoic acid methyl ester, 2-methyldiphenyl ketone, 3-methyldiphenyl ketone, 4-methyldiphenyl ketone, 3,3'-dimethyl-4- Diphenyl ketone derivatives such as methoxydiphenyl ketone and 2,4,6-trimethyldiphenyl ketone; aromatic carbonyl compounds, [4-(4-methylphenylthio)phenyl] -Phenyl ketone, xanthone, thioxanthone, 2-chlorothioxanthone, 4-chlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4 a thioxanthone derivative or a coumarin derivative such as dimethylthioxanthone, 2,4-diethylthioxanthone or 1-chloro-4-propoxythioxanthone.

The cleavage type photoradical generator generates a radical photoradical generator by cracking the compound by irradiation with an active energy ray, and specific examples thereof include aryl hexanes such as benzoin derivatives and acetophenone derivatives. The ketones, anthrones, mercaptophosphine oxides, thiobenzoic acid S-phenyls, titanocenes, and derivatives thereof are not limited thereto. Commercially available cracking type photoradical generators include, for example, 1-(4-dodecylbenzylidene)-1-hydroxy-1-methylethane and 1-(4-isopropylbenzylidene). )-1-hydroxy-1-methylethane, 1-benzylidene-1-hydroxy-1-methylethane, 1-[4-(2-hydroxyethoxy)-benzylidene] 1-hydroxy-1-methylethane, 1-[4-(propylene methoxyethoxy)-benzylidene]-1-hydroxy-1-methylethane, benzophenone, phenyl 1-hydroxy-cyclohexyl ketone, benzyl dimethyl aldehyde, bis(cyclopentadienyl)-bis(2,6-difluoro-3-pyrrolyl-phenyl)titanium, (η6-isopropyl Benzene)-(η5-cyclopentadienyl)-iron(II) hexafluorophosphate, trimethylbenzimidyldiphenylphosphine oxide, bis(2,6-dimethoxy-benzamide) -(2,4,4-trimethyl-pentyl)-phosphine oxide, bis(2,4,6-trimethylbenzylidene)-2,4-dipentyloxyphenylphosphine Oxide or bis(2,4,6-trimethylbenzylidene)phenyl-phosphine oxide, (4-morpholinylbenzylidene)-1-benzyl-1-dimethylamino Propane, 4-(methylthiobenzimidyl)-1-methyl-1-morpholinylethane, etc., but is not limited thereto.

In the active energy ray-curable adhesive used in the present invention, the photoradical generating agent contained in the electron beam curing type, that is, the dehydrogenating type or the cracking type photoradical generating agent may be used alone or in combination. Although it is used in plural, it is preferable that the photo-radical generating agent has a combination of one or more types of cracking type photoradical generating agents in terms of stability and hardenability. Among the crack-type photoradical generators, mercaptophosphine oxides are preferred, and more specifically, trimethylbenzhydryldiphenylphosphine oxide (trade name "DAROCURE TPO"; CIBA Japan Co., Ltd.), bis(2,6-dimethoxy-benzimidyl)-(2,4,4-trimethyl-pentyl)-phosphine oxide (trade name "CGI 403"; CIBA Japan Co., Ltd., or bis(2,4,6-trimethylbenzylidene)-2,4-dipentyloxyphenylphosphine oxide (trade name "Irgacure 819"; CIBA Japan Co., Ltd. ).

The active energy ray-curable adhesive may optionally contain a sensitizer. By using a sensitizer, the reactivity can be improved, and the mechanical strength and the subsequent strength of the adhesive layer can be further improved. The sensitizer can be suitably used as described above.

When the sensitizer is formulated, the amount thereof is preferably in the range of 0.1 to 20 parts by mass based on 100 parts by mass of the total amount of the active energy ray-curable adhesive.

The active energy ray-curable adhesive can be formulated with various additives within a range that does not impair the effect thereof. The additive to be added may, for example, be an ion scavenger, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, an antifoaming agent, or the like.

These components constituting the active energy ray-curable adhesive are usually used in a state of being dissolved in a solvent. When the active energy ray-curable adhesive contains a solvent, the active energy ray-curable adhesive can be applied to the coated surface and dried to obtain an adhesive layer. The component which is not dissolved in the solvent may be in a state of being dispersed in the system.

The active energy ray-curable adhesive is applied to the adhesion surface of the first retardation layer 1 and the second retardation layer 2, the adhesion surface of the second retardation layer 2 and the first retardation layer 1, or both. The contact surface of the first retardation layer 1 and the second retardation layer 2 and the adhesion surface of the second retardation layer 2 and the first retardation layer 1 may be subjected to corona treatment, plasma treatment, flame treatment, or the like in advance. A primer layer or the like can also be formed. The thickness of the primer layer is usually about 0.001 to 5 μm, preferably 0.01 μm or more, more preferably 4 μm or less, still more preferably 3 μm or less. If the primer layer is too thick, the appearance of the composite phase difference plate 5 tends to be poor.

The viscosity of the active energy ray-curable adhesive may be any viscosity which can be applied by various methods, and the viscosity at a temperature of 25 ° C is preferably in the range of 10 to 1000 mPa ‧ sec, more preferably 20 to 500 mPa ‧ sec The scope. If the viscosity is too small, there is a tendency that it is difficult to form a layer with a desired thickness. On the other hand, if the viscosity is too large, it becomes difficult to flow, and there is a tendency that it is difficult to obtain a uniform coating film without deviation. Here, the viscosity is an E-type viscosity agent, and after measuring the temperature of the adhesive to 25 ° C, the value is measured at 10 rpm.

As the active energy ray-curable adhesive, an electron beam curing type or an ultraviolet curing type can be used. In the present specification, the active energy ray is defined as an energy line that can decompose a compound that produces an active species to produce an active species. Examples of such active energy rays include visible light, ultraviolet light, infrared light, X-rays, alpha rays, beta rays, gamma rays, and electron beams.

In the electron beam curing type, the irradiation condition of the electron beam may be any condition suitable for curing the active energy ray-curable adhesive. For example, in the case of electron beam irradiation, the acceleration voltage is preferably from 5 kV to 300 kV, and more preferably from 10 kV to 250 kV. When the accelerating voltage is less than 5kV, the electron beam cannot reach the adhesive and there is insufficient hardening. If the accelerating voltage exceeds 300kV, the penetration force of the penetrating sample is too strong to cause the electron beam to rebound, and the transparent protective film is damaged or The edge of the polarizer. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the adhesive is insufficiently hardened, and if it exceeds 100 kGy, the retardation plate is damaged, the mechanical strength is lowered or yellowing is caused, and the desired optical characteristics are not obtained.

The electron beam irradiation is usually carried out by irradiation in an inert gas, and if necessary, in the atmosphere or by introducing a small amount of oxygen. By appropriately introducing oxygen, oxygen is deliberately generated on the surface of the phase difference plate irradiated by the first electron beam, and damage of the phase difference plate can be prevented, and the electron beam can be efficiently irradiated only to the adhesive.

In the ultraviolet curing type, the light irradiation intensity of the active energy ray-curable adhesive is not particularly limited as long as it depends on the respective compositions of the adhesive, and is preferably 10 to 1000 mW/cm ² . When the light irradiation intensity of the resin composition is less than 10 mW/cm ² , the reaction time becomes too long, and if it exceeds 1000 mW/cm ² , the radiant heat from the light source and the exothermic heat during polymerization of the composition, the composition of the adhesive There is a possibility that the material will yellow. Further, the irradiation intensity is preferably an intensity in a wavelength range effective for activation of a cationic polymerization initiator, more preferably a wavelength in a wavelength range of 400 nm or less, and more preferably a wavelength of 280 to 320 nm. The intensity in the range. The irradiation light is irradiated once or plural times with such light irradiation intensity, and the cumulative amount of light is suitably set to 10 mJ/cm ² or more, preferably 100 to 1000 mJ/cm ² . If the cumulative amount of light of the above-mentioned adhesive is less than 10 mJ/cm ² , the generation of the active species from the polymerization initiator is insufficient, so that the curing of the adhesive is insufficient. On the other hand, if the cumulative amount of light exceeds 1000 mJ/cm ² , the irradiation time becomes extremely long, which is disadvantageous for productivity improvement. At this time, depending on the type of the film of the retardation film to be used or the combination of the types of the adhesives, the required amount of light in which wavelength range (UVA (320 to 390 nm) or UVB (280 to 320 nm), etc.) is required Not the same.

The light source used in the polymerization hardening of the adhesive agent by irradiation with an active energy ray in the present invention is not particularly limited, and examples thereof include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, and a halogen lamp. Carbon arc lamp, tungsten wire lamp, potassium lamp, excimer laser, LED light source emitting light with a wavelength range of 380 to 440 nm, chemical lamp, black light lamp, microwave excited mercury lamp, metal halide lamp. From the viewpoint of energy stability and device simplicity, an ultraviolet light source having a light-emitting distribution at a wavelength of 400 nm or less is preferable.

[optical laminate]

The optical laminated system laminated polarizing plate of the present invention is formed by the above composite retardation plate. The optical laminate may also include a second adhesive layer that follows the polarizing plate and the composite phase difference plate. By adjusting the layer constitution of the composite phase difference plate laminated on the polarizing plate, an optical layered body having antireflection properties can be obtained. An optical laminate having antireflection properties such as a circularly polarizing plate. In the image display device, by providing an optical layered body having antireflection performance on the visual recognition side of the image display panel, it is possible to suppress a decrease in visibility due to reflection of external light.

The layer structure of the polarizing plate and the optical layered body formed of the composite phase difference plate due to the reduction in visibility due to reflection of external light can be suppressed, and specifically, for example, v) sequentially layered from the visual recognition side Optical layered body of a layered layer formed by a polarizing plate, a 1/2 wavelength layer (first retardation layer), a second adhesive layer, and a 1/4 wavelength layer (second retardation layer); vi) visually recognized side An optical layered body of a layered layer formed by an optical compensation layer (second retardation layer) such as a sequential laminated polarizing plate, a 1/4 wavelength layer (first retardation layer), a second adhesive layer, or a positive C plate .

The thickness of the optical laminate is usually from 50 to 500 μm, preferably from 50 to 200 μm, more preferably from 50 to 150 μm, from the viewpoint of thinning.

<Polarizing plate>

The polarizing plate may have a film which can obtain a polarizing function of linearly polarized light from the transmitted light. The film may, for example, be a film obtained by adsorbing a dye having an anisotropic absorption property or a film containing a film having a dye having an anisotropy absorption as a polarizer. The dye having an anisotropy of absorption may, for example, be a dichroic dye. The film for coating a dye having an anisotropic property to be used in a polarizer may, for example, be a stretched film which adsorbs a dye having an anisotropy of absorption; or a composition containing a dichroic dye having a liquid crystal property, or a composition containing two A film of a liquid phase layer obtained from a composition of a coloring dye and a polymerizable liquid crystal.

(Polarizing plate with stretched film as polarizer)

Hereinafter, a polarizing plate having a stretched film having a dye having an absorbing anisotropy adsorbed thereon as a polarizer will be described. A stretched film which is a dye adsorbed by a polarizer and which absorbs an anisotropic dye, is usually produced by the following steps: a step of uniaxially stretching a polyvinyl alcohol-based resin film; and a polyvinyl dye with a dichroic dye a step of dyeing the resin film to adsorb the dichroic dye; a step of treating the polyvinyl alcohol-based resin film having the dichroic dye adsorbed thereon with a boric acid aqueous solution; and a step of performing water washing after the boric acid aqueous solution treatment treatment . The polarizer can be directly used as a polarizing plate, and a transparent protective film can be attached to at least one surface of the polarizer to be used as a polarizing plate.

The polyvinyl alcohol-based resin can be obtained by saponifying a polyvinyl acetate-based resin. The polyvinyl acetate-based resin may be a copolymer of vinyl acetate and another monomer copolymerizable with vinyl acetate in addition to polyvinyl acetate which is a homopolymer of vinyl acetate. Other monomers which can be copolymerized with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamides having an ammonium group, and the like.

The degree of saponification of the polyvinyl alcohol-based resin is usually from about 85 to 100 moles, preferably 98 mole% or more. The polyvinyl alcohol-based resin may also be modified, and for example, polyethylene formaldehyde or polyethylene acetaldehyde modified with an aldehyde may also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually from about 1,000 to 10,000, preferably from 1,500 to 5,000.

A film of such a polyvinyl alcohol-based resin is used as a film of a polarizing film. The method for forming the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a known method. The film thickness of the polyvinyl alcohol-based raw film may be, for example, about 10 to 150 μm.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be carried out before dyeing with a dichroic dye, simultaneously with dyeing, or after dyeing. When uniaxial stretching is performed after dyeing, the uniaxial stretching may be carried out before the boric acid treatment or in the boric acid treatment. Further, uniaxial stretching can also be performed at these plural stages. In the case of uniaxial stretching, it may be uniaxially stretched between rolls having different circumferential speeds, or may be uniaxially stretched using a heat roll. In addition, the uniaxial stretching may be a dry stretching in which stretching is carried out in the air, or may be a wet stretching in which the polyvinyl alcohol-based resin film is swollen with a solvent. The draw ratio is usually about 3 to 8 times.

The dyeing of the polyvinyl alcohol-based resin film by a dichroic dye can be carried out, for example, by a method in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing a dichroic dye. The dichroic dye is specifically an iodine or a dichroic organic dye. The dichroic dye includes a dichroic direct dye composed of a diazo compound such as C.I. DIRECT RED 39, a dichroic direct dye, a compound such as trisazo or tetrazo. The polyvinyl alcohol-based resin film is preferably subjected to an immersion treatment of immersing in water before the dyeing treatment.

When iodine is used as the dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine or potassium iodide for dyeing is usually employed. The content of iodine in the aqueous solution is usually about 0.01 to 1 part by mass per 100 parts by mass of water. Further, the content of potassium iodide is usually about 0.5 to 20 parts by mass per 100 parts by mass of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 °C. Further, the immersion time (dyeing time) of the aqueous solution is usually about 20 to 1800 seconds.

On the other hand, when a dichroic organic dye is used as the dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye to perform dyeing is generally employed. The content of the dichroic organic dye in the aqueous solution is usually 1 × 10 ^-4 to 10 parts by mass, more preferably 1 × 10 ^-3 to 1 × 10 ^-2 parts by mass per 100 parts by mass of water. The aqueous solution may also contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the aqueous solution of the dichroic dye used for dyeing is usually about 20 to 80 °C. Further, the immersion time (dyeing time) of the aqueous solution is usually about 10 to 1800 seconds.

The boric acid treatment after dyeing with a dichroic dye can be usually carried out by a method of immersing the dyed polyvinyl alcohol-based resin film in a boric acid aqueous solution. The content of boric acid in the aqueous boric acid solution is usually from about 2 to 15 parts by mass, preferably from about 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic dye, the aqueous boric acid solution preferably contains potassium iodide. In this case, the potassium iodide content is usually from 0.1 to 15 parts by mass, preferably from 5 to 12 parts by mass per 100 parts by mass of water. about. The immersion time in the aqueous boric acid solution is usually from about 60 to 1200 seconds, preferably from 150 to 600 seconds, more preferably from 200 to 400 seconds. The temperature of the boric acid treatment is usually 50 ° C or higher, preferably 50 to 85 ° C, more preferably 60 to 80 ° C.

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

After washing with water, it is dried to obtain a polarizer. The drying treatment can be carried out, for example, using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually about 30 to 100 ° C, preferably about 50 to 80 ° C. The drying treatment time is usually about 60 to 600 seconds, preferably 120 to 600 seconds. By drying, the moisture content of the polarizer can be reduced to a practical level. The moisture content is usually from about 5 to 20% by mass, preferably from 8 to 15% by mass. When the water content is less than 5% by mass, the flexibility of the polarizer is lost, or the polarizer is damaged or broken after the drying. Further, when the water content is more than 20% by mass, the thermal stability of the polarizer may be deteriorated.

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

The material of the protective film to be bonded to one surface or both surfaces of the polarizer is not particularly limited, and examples thereof include an acetic acid fiber composed of a resin such as a cyclic polyolefin resin film, cellulose triacetate or cellulose diacetate. A polyester resin film made of a resin such as a resin film, polyethylene terephthalate, polyethylene naphthalate or polybutylene terephthalate, or a polycarbonate resin film. A film known in the art such as an acrylic resin film or a polypropylene resin film. The thickness of the protective film is usually 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, and usually 5 μm or more, and preferably 20 μm or more, from the viewpoint of thickness reduction. Further, the protective film on the visual recognition side may have a phase difference or may have no phase difference. On the other hand, the phase difference of the protective film laminated on the first retardation layer side is preferably a phase difference of 10 nm or less.

(Polarizer with a liquid crystal layer as a polarizer)

Hereinafter, a polarizing plate having a film having a liquid crystal layer as a polarizer will be described. The film which is used as a polarizer and which has a dye having an absorbing anisotropy is, for example, a film obtained by coating a composition containing a liquid crystal dichroic dye or a composition containing a dichroic dye and a liquid crystal compound. Wait. The film may be used alone as a polarizing plate, or may be used as a polarizing plate in a configuration in which a protective film is provided on one or both sides. The protective film may be, for example, the same as the above-described polarizing plate having a stretched film as a polarizer.

The film coated with the dye having anisotropic absorption is preferably thin, but if it is too thin, the strength is lowered, and the workability tends to be deteriorated. The thickness of the film is usually 20 μm or less, preferably 5 μm or less, more preferably 0.5 μm or more and 3 μm or less.

The film which is coated with the dye which absorbs the anisotropy is used, and a film as described in Unexamined-Japanese-Patent No. 2012-33249 is mentioned, for example.

The optically laminated body formed by laminating the composite retardation film and the polarizing plate can be obtained by directly applying the dye having an absorbing anisotropy to the first retardation plate side of the composite retardation film. In this case, the composite retardation film and the polarizing plate may be laminated without the second adhesive layer.

<2nd layer>

The second adhesive layer can be composed of, for example, an adhesive, a water-based adhesive, an active energy ray-curable adhesive, and the like. In the case where the second adhesive layer is a cured layer of an active energy ray-curable adhesive, even when the optical laminate including the composite retardation layer of the present invention is bent, the wrinkles of the bent portion can be further suppressed. It is better to produce. In the present specification, the term "second adhesive layer" is not only an adhesive layer composed of an adhesive but also an adhesive layer composed of an adhesive.

The adhesive constituting the second adhesive layer and the water-based adhesive active energy ray-curable adhesive can be applied to the description of the first adhesive layer described above. When the first adhesive layer and the second adhesive layer are formed of an active energy ray-curable adhesive, the first adhesive layer and the second adhesive layer may be formed of the same active energy ray-curable adhesive, or may have different active energy. A wire hardening type of adhesive is formed.

[Manufacturing method of composite phase difference plate and optical laminate]

The composite retardation film of the present invention can be produced by the following method: the first phase difference including the first retardation layer 13, the first alignment layer 12, and the first base material layer 11 shown in Fig. 3(A) The layer 10 and the second retardation layer 20 including the second phase difference display layer 23, the second alignment layer 22, and the second base material layer 21 shown in FIG. 3(B) are passed through the first adhesive layer 40. To manufacture. Further, in the composite phase difference plate of the present invention, the first retardation layer 13, the first alignment layer 12, the first base material layer 11, the first adhesive layer 40, and the second base material layer 21 may be sequentially laminated. The laminated body of the second alignment layer 22 and the second phase difference display layer 23.

The method of following the first retardation layer 10 and the second retardation layer 20 may be, for example, any one of the bonding surface of the first retardation layer 10 or the bonding surface of the second retardation layer 20 or The adhesive is applied to the other bonding surface, and the adhesive constituting the first adhesive layer 40 is cured.

For the application of the adhesive constituting the first adhesive layer 40, for example, various coating methods such as a knife coater, a wound bar coater, a die coater, a comma coater, and a gravure coater can be used.

The method of curing the adhesive constituting the first adhesive layer can be appropriately selected by a method of curing depending on the type of the adhesive. When the adhesive is an active energy ray-curable adhesive, a method of hardening with an active energy ray as described above is preferred. Either or both of the bonding surface of the first retardation layer 10 or the bonding surface of the second retardation layer 20 may be subjected to corona treatment, plasma treatment, or the like, or a primer layer may be formed.

The composite retardation layer of the present invention may be a laminate as shown in Fig. 3(C), or may be a laminate in which at least one of the first base layer 11 and the second base layer 21 is peeled off. Moreover, the laminated body in which the first base material layer 11 and the first alignment layer 12 are peeled off from the laminated body as shown in Fig. 3(C) may be used as the laminated body shown in Fig. 3(C). The layered body of the second base material layer 21 and the second alignment layer 22 is peeled off from the body.

[Use of optical laminate]

The optical layered body which is a circularly polarizing plate can be used for various image display apparatuses as an optical layered body which is provided on the viewing side of the image display panel and which imparts antireflection performance. The image display device refers to a device having an image display panel, and includes a light-emitting element or a light-emitting device as a light-emitting source. The image display device may, for example, be a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, or an electron emission display device (for example, a field emission display device (FED) ), surface electric field emission display device (SED), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection display device (such as grating light valve (GLV) display device, with digital micro A mirror device (DMD) display device), a piezoelectric ceramic display, and the like. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, and a projection type liquid crystal display device. The image display device may be an image display device that displays a two-dimensional image, or may be a stereoscopic image display device that displays a three-dimensional image. In particular, an optical laminate of a circularly polarizing plate can be effectively used for an organic electroluminescence (EL) display device which can have an image display panel having a curved portion.

According to the present invention, even when the optical layered body is bent along the surface of the image display panel having the curved portion, the optical layered body which does not wrinkle can be obtained.

 [Examples]  

Hereinafter, the present invention will be described in more detail by way of examples.

[Production Example of Phase Difference Layer]

(1) Modulation of composition for forming a liquid crystal phase difference

80 parts of the polymerizable liquid crystal compound (A1), 20 parts of the polymerizable compound (A2), 6 parts of a polymerization initiator, 0.1 part of a leveling agent, and 400 parts of cyclopentanone were mixed, and the resulting mixture was stirred at 80 ° C for 1 hour. Thereby, the liquid crystal phase difference forming composition (1) was obtained.

Hereinafter, the polymerizable liquid crystal compound A1, the polymerizable compound A2, the polymerization initiator, and the leveling agent used are disclosed. Further, the polymerizable liquid crystal compound A1 and the polymerizable compound A2 are synthesized by the method described in JP-A-2010-31223.

Polymeric Compound A1:

Polymeric Compound A2:

Polymerization initiator: 2-dimethylamino-2-benzyl-1-(4-morpholinylphenyl)butan-1-one (IRGACURE 369; manufactured by Ciba Specialty Chemicals Co., Ltd.), leveling agent ( 0.1 part): polyacrylate compound (BYK-361N; manufactured by BYK-Chemie Co., Ltd.)

(2) Modulation of composition for forming an alignment layer

(2-1) Modulation of composition for forming alignment layer (1)

5 parts of the compound shown below and 95 parts of cyclopentanone were mixed, and the obtained mixture was stirred at 80 ° C for 1 hour, whereby the composition for forming an alignment layer (1) was obtained.

Light aligning material (5 parts):

(2-2) Modulation of composition for forming alignment layer (2)

In the SUNEVER SE-610 (manufactured by Nissan Chemical Industry Co., Ltd.) of the alignment polymer, 2-butoxyethanol was added to obtain a composition (2) for forming an alignment layer. Further, the amount of the solid content in the composition for forming an alignment layer (2) was 1%.

(3) Manufacturing example of phase difference layer

(3-1) Production Example of Phase Difference Layer (1) (Production Example of Reverse Dispersion 1/4 Wavelength Layer)

The surface of the film of polyethylene terephthalate (PET) was treated once using a corona treatment apparatus (AGF-B10, manufactured by Kasuga Electric Co., Ltd.) under the conditions of an output of 0.3 kW and a treatment rate of 3 m/min. On the surface subjected to the corona treatment, the composition for forming an alignment layer (1) was applied by a bar coater, and dried at 80 ° C for 1 hour, using a polarized UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO Electric Co., Ltd.) Polarized UV exposure was performed at a cumulative light amount of 100 mJ/cm ² . The film thickness of the obtained alignment layer was measured by a laser microscope (LEXT, manufactured by Olympus Co., Ltd.) to be 100 nm. Next, the liquid crystal phase difference forming composition (1) was applied onto the alignment layer by a bar coater, and dried at 120 ° C for 1 minute, and then a high pressure mercury lamp (Unicure VB-15201 BY-A, manufactured by USHIO Electric Co., Ltd.) was used. Irradiation of ultraviolet rays (in a nitrogen atmosphere, wavelength: 365 nm, cumulative light amount at a wavelength of 365 nm: 1000 mJ/cm ² ), whereby a retardation layer having a liquid crystal layer as a phase difference presentation layer (reverse dispersion 1/4 wavelength layer) was obtained. . The phase difference of the phase difference layer obtained was measured and found to be Re (550) = 138 nm and Rth (550) = 72 nm. Further, as a result of measuring the phase difference between the wavelength of 450 nm and the wavelength of 650 nm, Re (450) = 121 nm and Re (650) = 141 nm. The relationship of the phase difference values in the in-plane of each wavelength is as follows. Further, the phase difference value of the polyethylene terephthalate film is not contained.

Re(450)/Re(550)=0.87

Re(650)/Re(550)=1.02

(3-2) Manufacturing Example of Phase Difference Layer (2) (Production Example of Layer C)

The film surface of the cycloolefin polymer (COP) was treated once using a corona treatment apparatus under the conditions of an output of 0.3 kW and a treatment rate of 3 m/min. On the surface subjected to the corona treatment, the composition for forming an alignment layer (2) was applied by a bar coater, and dried at 90 ° C for 1 minute to obtain an alignment film. The film thickness of the obtained alignment layer was measured by a laser microscope and found to be 34 nm. Next, the liquid crystal phase difference forming composition (1) was applied onto the alignment layer by a bar coater, and dried at 90 ° C for 1 minute, and then irradiated with ultraviolet rays using a high-pressure mercury lamp (in a nitrogen atmosphere, wavelength: 365 nm, wavelength 365 nm). The cumulative light amount: 1000 mJ/cm ² ), whereby a retardation layer (C layer) having a liquid crystal layer as a phase difference display layer was obtained. The film thickness of the phase difference layer obtained by a laser microscope was 450 nm. Further, as a result of measuring the phase difference of the phase difference layer 2 at a wavelength of 550 nm, Re (550) = 1 nm and Rth (550) = -70 nm. Further, the phase difference value of the cycloolefin polymer film is not contained.

[Modulation of Photocuring Type Adhesives 1 to 11]

(1) Preparation of cationic hardening component

The cationic hardening component shown below was prepared.

(A-1) 3',4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Dicel Co., Ltd.),

(A-2) 1,2-Butoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (trade name: EHPE3150, a company made by Dicel),

(B-1) Neopentyl glycol diglycidyl ether (trade name: EX-211, manufactured by Nagase ChemteX Co., Ltd.),

(B-2) 1,4-butanediol diglycidyl ether (trade name: EX-214, manufactured by Nagase ChemteX Co., Ltd.),

(B-3) 2-ethylhexyl epoxidized ether (trade name: EX-121, manufactured by Nagase ChemteX Co., Ltd.),

(C-1) Resorcinol diglycidyl ether (trade name: EX-201, manufactured by Nagase ChemteX Co., Ltd.),

(C-2) polyfunctional epoxidized ether (trade name: VG3101L, manufactured by Printeq Co., Ltd.),

(D-1) 3-ethyl-3{[(3-ethyloxycyclobutane-3-yl)methoxy]methyl}oxycyclobutane (trade name: OXT-221, East Asia Synthetic Co., Ltd.) the company)

(D-2) p-xylene dioxycyclobutane (trade name: OXT-121, East Asia Synthetic Co., Ltd.)

(2) Preparation of free radical curable components

The free radical curable component shown below was prepared.

(E-1) 4-hydroxybutyl acrylate (trade name: 4HBA, Nippon Kasei Co., Ltd.),

(E-2) 1,4-cyclohexanedimethanol monoacrylate (trade name: CHDMMA, manufactured by Nippon Kasei Co., Ltd.)

(E-3) Dimethyl acrylamide (trade name: DMAA, Co., Ltd.)

(E-4) Polyurethane acrylate (trade name: Violet UV-3000B, manufactured by Nippon Synthetic Chemical Co., Ltd.)

(3) cationic polymerization initiator and radical polymerization initiator

The cationic polymerization initiator and the radical polymerization initiator (referred to as "starting agent" in Table 1) shown below were prepared.

(F-1) cationic polymerization initiator (trade name: CPI-100, manufactured by San-Apro Co., Ltd.),

(F-2) cationic polymerization initiator (trade name: IRGACURE 1173, manufactured by BASF Corporation)

(4) Preparation of sensitizer

Prepare the sensitizer shown below.

(G-1) 1,4-diethoxynaphthalene (abbreviated as "DEN" in Table 1)

(5) Modulation of adhesives 1 to 11

The cationically curable component, the cationic polymerization initiator, or the radical curable component and the radical polymerization initiator are mixed at a mixing ratio (unit: parts) shown in Table 1, and then defoamed and prepared. Photocuring type adhesives 1 to 15. Further, the cationic polymerization initiator (F-1) was prepared by using a 50% propylene carbonate solution, and the solid content thereof is shown in Table 1.

[Modulation of Adhesive 1]

(1) Preparation of materials

The acrylic base polymer (G-1), the isocyanate crosslinking agent (G-2), and the decane coupling agent (G-3) shown below were prepared.

(H-1) Copolymer of butyl acrylate, methyl acrylate, acrylic acid and hydroxyethyl acrylate

(H-2) Ethyl acetate solution of trimethylolpropane adduct of toluene diisocyanate (solid content: 75%) ("Coronate L" (trade name), manufactured by Tosoh Corporation)

(H-3) 3-glycidoxypropyltrimethoxy decane, liquid ("KBM-403" (trade name), manufactured by Shin-Etsu Chemical Co., Ltd.)

(2) Modulation of Adhesive 1

100 parts by mass of the above-mentioned acrylic matrix polymer (H-1), 0.2 parts by mass of an isocyanate crosslinking agent (H-2), and 0.2 parts by mass of a decane coupling agent (H-3) were mixed, and the mixture was sufficiently stirred. The ester is diluted, whereby the adhesive 1 is prepared.

[Viscosity measurement]

To the above-mentioned prepared adhesives 1 to 11, an E-type viscometer "TVE-25" manufactured by Toki Sangyo Co., Ltd. was used, and the viscosity at a temperature of 25 ° C and 10 rpm was measured. The results are shown in Table 1.

[Manufacturing Example of Composite Phase Difference Plate]

(1-1) Manufacture of the first composite phase difference plate (Examples 1 to 12 and Comparative Example 1)

a 1/2 wavelength layer (first retardation layer) composed of three layers of a phase difference display layer, an alignment layer, and a substrate layer belonging to a liquid crystal layer, and a phase difference display layer, an alignment layer, and a substrate belonging to the liquid crystal layer The 1/4 wavelength layer (second retardation layer) composed of three layers is cut into small pieces of 100 × 100 mm, and the first phase is sequentially laminated so that the phase difference of each phase difference layer is inside. The poor layer, the adhesives shown in Table 2 (adhesives 1 to 12), and the second retardation layer. Then, the laminates were bonded to each other to obtain a laminate. Then, an ultraviolet irradiation device equipped with an ultraviolet lamp "H blub" manufactured by FUSION UV SYSTEMS Co., Ltd. was used on both surfaces of the laminate to have a light irradiation intensity of 400 mW/cm. ^{2. A method in} which the cumulative light amount of the wavelength of 280 to 320 nm is 400 mJ/cm ² , and ultraviolet rays are irradiated to cure the photocurable adhesive to form a cured layer to obtain a laminate. The first base material layer and the second base material layer were peeled off from the obtained laminated body, and then they were used as test pieces of the composite retardation plates (Examples 1 to 12 and Comparative Example 1).

(2) Manufacture of the first composite phase difference plate (Comparative Examples 2 and 3)

Similarly to the above (1), the 1/2 wavelength layer (first retardation layer) composed of three layers of the phase difference presentation layer, the alignment layer, and the base layer belonging to the liquid crystal layer and the phase difference belonging to the liquid crystal layer a quarter-wavelength layer (second retardation layer) composed of three layers of a presentation layer, an alignment layer, and a substrate layer, and a small piece of 100×100 mm is cut out, and the phase difference of each phase difference layer is revealed to be inside. In this manner, the first retardation layer, the adhesive 1, and the second retardation layer are laminated in this order. Next, these flat sheets are bonded together to obtain a laminate. The first base material layer and the second base material layer were peeled off from the obtained laminated body, and then they were used as test pieces of composite phase difference plates (Comparative Examples 2 and 3).

(3) Manufacture of the second composite phase difference plate (Examples 13 to 24 and Comparative Example 4)

The reverse dispersion 1/4 wavelength layer (first retardation layer) manufactured by the above ((3-1) Production Example (1) of retardation layer) and the above-mentioned "(3-2) phase difference layer) In the layer C produced in the example (2), a small piece of 100 × 100 mm is cut out, and the phase difference display layer of each phase difference layer is formed inside, and the first retardation layer and the third phase difference layer are sequentially stacked. The subsequent agent (adhesives 1 to 11) and the second retardation layer. Then, the laminates were bonded to each other to obtain a laminate. Then, an ultraviolet irradiation device equipped with an ultraviolet lamp "H blub" manufactured by FUSION UV SYSTEMS Co., Ltd. was used on both surfaces of the laminate to have a light irradiation intensity of 400 mW/cm. ^{2. A method in} which the cumulative light amount of the wavelength of 280 to 320 nm is 400 mJ/cm ² , and ultraviolet rays are irradiated to cure the photocurable adhesive to form a cured layer to obtain a laminate. The first base material layer and the second base material layer were peeled off from the obtained laminated body, and then they were used as test pieces of composite phase difference plates (Examples 13 to 24 and Comparative Example 4).

(2-2) Manufacture of the second composite phase difference plate (Comparative Examples 5 and 6)

In the same manner as in the above (3), the reverse dispersion 1/4 wavelength layer (first retardation layer) manufactured by the above-mentioned "(3-1) Production Example (1) of retardation layer", and the above "(3) -2) The C layer produced in the manufacturing example (2) of the retardation layer is cut into small pieces of 100 × 100 mm, and the first phase is sequentially laminated so that the phase difference display layer of each phase difference layer is inside. The difference layer, the adhesive 1, and the second retardation layer. Next, these flat sheets are bonded together to obtain a laminate. The first base material layer and the second base material layer were peeled off from the obtained laminated body, and then they were used as test pieces of composite phase difference plates (Comparative Examples 5 and 6).

(5) Determination of the thickness of the composite phase difference plate and the adhesive layer

The thickness of the test piece of the composite phase difference plate produced above was measured by a contact type film thickness meter [trade name "DIGIMICRO MH-15M" manufactured by Nikon Co., Ltd.]. Further, the thickness of the adhesive layer or the adhesive layer after curing was measured in the same manner as above. The measurement results are shown in Tables 2 and 3.

(6) Determination of puncture slope of composite phase difference plate

The puncture slope of the test piece of the composite phase difference plate manufactured above was calculated. The puncture strength was measured using a small tabletop tester (trade name "EZ Test" manufactured by Shimadzu Corporation) equipped with a puncture aid having a diameter of 1 mm and a tip radius of 0.5R. The obtained puncture strength A (kg), puncture depth B (mm) after splitting, and composite phase difference plate thickness d (mm) are given by the following formula: E=A/(B×d)

The puncture slope E (kg/mm ² ) per unit film thickness was calculated. Further, the puncture slope of the composite phase difference plate is an average value of the puncture slopes E of five or more composite phase difference plates produced under the same conditions. The measurement results are shown in Tables 2 and 3.

[Manufacture of optical laminate]

(7) Manufacture of polarizing plates

A polyvinyl alcohol film having an average polymerization degree of about 2,400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm was immersed in pure water at 30 ° C, and then immersed in an iodine/potassium iodide/water mass ratio of 0.02/2/ at 30 ° C. In an aqueous solution of 100, iodine dyeing (iodine dyeing step) was carried out. The polyvinyl alcohol film after the iodine dyeing step was immersed in an aqueous solution of potassium iodide/boric acid/water in a mass ratio of 12/5/100 at 56.5 ° C to carry out boric acid treatment (boric acid treatment step). The polyvinyl alcohol film after the boric acid treatment step was washed with pure water at 8 ° C, and then dried at 65 ° C. Further, a polarizer having an iodine adsorption-adsorbed to polyvinyl alcohol (thickness after stretching was 27 μm) was obtained. At this time, stretching is performed in the iodine dyeing step and the boric acid treatment step. The total draw ratio in this stretching was 5.3 times. On both sides of the obtained polarizer, a saponified cellulose triacetate film (trade name: KC4UYTAC, manufactured by Konica Minta, thickness: 40 μm) was attached to a nip roll through a water-based adhesive. The obtained laminate was kept at a temperature of 430 N/m while being dried at 60 ° C for 2 minutes to obtain a polarizing plate having a cellulose acetate film as a protective film on both sides. The above-mentioned water-based adhesive is added to 100 parts of water, and 3 parts of carboxyl modified polyvinyl alcohol (KURARAY POVAL KL318, manufactured by KURARAY) and water-soluble polyamide resin (Sumirez Resin 650, manufactured by Chem Chemex, solid content concentration) are added. 30% aqueous solution) 1.5 parts to prepare.

(8) Manufacture of the first optical laminate (Examples 1 to 12 and Comparative Examples 1 to 3)

The polarizing plate produced in the above (7) and the first composite retardation film produced in the above (1) or (2) are such that the first retardation layer side of the first composite retardation film is a continuous surface. The first optical laminate was produced by laminating with an acrylic adhesive (film thickness: 25 μm). Specifically, the counterclockwise rotation of the slow axis of the first retardation layer is positive with respect to the absorption axis direction (0°) of the polarizing plate manufactured as described above, and is laminated so as to be -15°, and The transmission axis of the polarizing plate manufactured as described above and the slow axis of the second retardation layer were layered at -75°.

(9) Manufacture of the second optical laminate (Examples 13 to 24 and Comparative Examples 4 to 6)

The second optical laminate was produced by using the polarizing plate produced in the above (8) and the second composite retardation film produced in the above (3) or (4). Specifically, the polarizing plate manufactured as described above is cut into a small piece of 100 × 100 mm so that the slow axis of the first retardation layer is 45° with respect to the absorption axis direction (0°) of the polarizer. This was bonded to the second composite retardation film so that the first retardation layer was placed on the back surface, and the optical laminate was formed into a circularly polarizing plate by using an acrylic adhesive (film thickness: 25 μm).

[Test Example] (Evaluation of the occurrence of wrinkles)

The first optical layered product produced in the above (8) and the second optical layered product produced in the above (9) are made of an acrylic adhesive (film thickness: 25 μm so that the composite phase difference plate side is a bonding surface). The aluminum plate having the bent portion (2R) was attached to the aluminum plate having the bent portion (2R) to visually observe the occurrence of wrinkles in the bent portion, and the occurrence of wrinkles was evaluated based on the following criteria. The evaluation results are shown in Tables 2 and 3.

1: No wrinkles were observed in the bent portion, 2: only a few wrinkles were observed in the curved portion (number of wrinkles: 1 to 5), and 3: wrinkles were confirmed in the bent portion (number of wrinkles: 5 or more) ).

Claims (13)

A composite phase difference plate includes a first retardation layer, a second retardation layer, and a first subsequent layer following the first retardation layer and the second retardation layer, wherein the puncture slope per unit thickness is 6 kg/ Mm ² to 15kg/mm ² .  The composite retardation film according to claim 1, wherein the first adhesive layer is a cured layer of an active energy ray-curable adhesive.    The composite phase difference plate according to claim 1 or 2, wherein the first retardation layer is a 1/2 wavelength layer, and the second retardation layer is a 1/4 wavelength layer.    The composite retardation film according to claim 1 or 2, wherein the first retardation layer is a 1/2 wavelength layer or a 1/4 wavelength layer, and the second retardation layer is an optical compensation layer.    The composite phase difference plate according to any one of claims 1 to 4, wherein at least one of the first retardation layer and the second retardation layer includes a phase difference presentation layer belonging to the liquid crystal layer.    The composite phase difference plate according to any one of claims 1 to 5, which has a thickness of from 2 μm to 50 μm.    An optical laminate comprising a polarizing plate and a composite phase difference plate according to any one of claims 1 to 6, wherein the composite phase difference plate is located in the first phase difference layer The surface of the polarizing plate is laminated to face.    The optical laminate according to claim 7, which is a circular polarizing plate.    The optical laminate according to claim 7 or 8, further comprising a second adhesive layer which is followed by the polarizing plate and the composite retardation film.    The optical laminate according to claim 9, wherein the second adhesive layer is a cured layer of an active energy ray-curable adhesive.    An image display device comprising an image display panel, and an optical layered body according to any one of claims 7 to 10, which is disposed on the visual recognition side of the image display panel.    The image display device according to claim 11, wherein the optical layering system is disposed such that the polarizing plate is located on a side of the visibility side.    An image display device according to claim 12, which is an organic electroluminescence display device.