KR20230116803A - An image display device comprising an optical film with a pressure-sensitive adhesive layer and the optical film with a pressure-sensitive adhesive layer - Google Patents

Abstract

The present invention provides a thin optical film in which discoloration is suppressed. The optical film with an adhesive layer of the present invention includes a polarizer and a polarizing plate including a protective layer disposed on at least one side of the polarizer, a retardation layer, and an adhesive layer in this order from the visual recognition side, and the water vapor transmission rate of the retardation layer is It is 300 g/m 2 24 h or more, the end of the pressure-sensitive adhesive layer is located inside the end of the polarizer in cross section, and the horizontal distance between the end of the pressure-sensitive adhesive layer and the end of the polarizer is 0 μm to 50 μm.

Description

An image display device comprising an optical film with a pressure-sensitive adhesive layer and the optical film with a pressure-sensitive adhesive layer

The present invention relates to an optical film with an adhesive layer and an image display device comprising the optical film with an adhesive layer.

BACKGROUND OF THE INVENTION In recent years, image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (eg, organic EL display devices and inorganic EL display devices) are rapidly spreading. In an organic EL display device equipped with an organic EL panel, since the organic EL panel includes a highly reflective metal layer, problems such as reflection of external light and reflection of a background tend to occur. Accordingly, it is known to prevent these problems by providing a circular polarizing plate including a λ/4 plate on the viewing side (for example, Patent Documents 1 to 3).

As the circular polarizing plate, by using a λ/4 plate having reverse wavelength dispersion characteristics, excellent antireflection characteristics can be realized. On the other hand, from the viewpoint of thinning the image display device, there is a demand for thinning the circular polarizing plate as well.

Japanese Unexamined Patent Publication No. 2003-311239 Japanese Unexamined Patent Publication No. 2002-372622 Japanese Patent Publication No. 3325560

For the purpose of thinning the circular polarizing plate, the present inventors produced a circular polarizing plate using a thin λ/4 plate, the moisture permeability of the λ/4 plate increased, and as a result, discoloration occurred at the end compared to the conventional circular polarizing plate. What is easy to happen has been identified.

The present invention has been made to solve the above problems, and its main object is to provide a thin optical film with suppressed discoloration.

Optical films, such as a circular polarizing plate, are normally provided with the adhesive layer for bonding to an image display cell. As a result of intensive studies to achieve the above object, the inventors of the present invention have found that when an optical film with a pressure-sensitive adhesive layer is cut into a desired shape, the end portion of the pressure-sensitive adhesive layer is missing and the retardation layer is exposed, which affects the decolorization of the polarizer. While discovering that, the idea was obtained that the said discoloration could be suppressed by controlling the lack of the edge part of the said adhesive layer within a predetermined range, and came to complete this invention.

According to one aspect of the present invention, a polarizer including a polarizer and a protective layer disposed on at least one side of the polarizer, a retardation layer, and an adhesive layer are provided in this order from the viewing side, and the retardation layer has a water vapor transmission rate of 300 g / m 24h or more, and in a sectional view, the end of the pressure-sensitive adhesive layer is located inside the end of the polarizer, and the horizontal distance between the end of the pressure-sensitive adhesive layer and the end of the polarizer is 0 μm to 50 An optical film with a pressure-sensitive adhesive layer having a thickness of .mu.m is provided.

In one embodiment, the polarizing plate includes the polarizer and a protective layer disposed only on the viewing side of the polarizer.

In one embodiment, the thickness of the polarizer is 10 μm or less.

In one embodiment, the amount of strain at a stress of 0.4 N when a stress-strain measurement is performed at 23° C. of the pressure-sensitive adhesive layer is 900% or less.

In one embodiment, the retardation layer includes an alignment-fixed layer of a liquid crystal compound, and Re(550) and Re(450) of the alignment-fixed layer of the liquid crystal compound are 0.8≤Re(450)/Re(550)< 1, Re (550) of the alignment-fixed layer of the liquid crystal compound is 100 nm to 190 nm, and the angle between the slow axis of the alignment-fixed layer of the liquid crystal compound and the absorption axis of the polarizer is 40° to 50°. am.

According to one situation of this invention, the image display apparatus provided with the said optical film with an adhesive layer is provided.

In one embodiment, the image display device is an organic electroluminescence display device.

According to the optical film with a pressure-sensitive adhesive layer of the present invention, as a result of suppressing exposure of the retardation layer, discoloration of the polarizer can be suppressed even when a thin retardation layer is used.

1 is a schematic sectional view of an optical film with a pressure-sensitive adhesive layer according to one embodiment of the present invention.
2 is a schematic cross-sectional view of an optical film with a pressure-sensitive adhesive layer according to another embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described, this invention is not limited to these embodiment.

(Definition of Terms and Symbols)

Definitions of terms and symbols in this specification are as follows.

(1) Refractive index (nx, ny, nz)

'nx' is the refractive index in the direction in which the in-plane refractive index is maximized (ie, the slow axis direction), 'ny' is the refractive index in the direction orthogonal to the slow axis within the plane (ie, the fast axis direction), and 'nz' is is the refractive index in the thickness direction.

(2) In-plane phase difference (Re)

'Re(λ)' is an in-plane retardation measured with light having a wavelength of λ nm at 23°C. For example, 'Re(550)' is an in-plane retardation measured with light having a wavelength of 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ)=(nx-ny)×d when the thickness of the layer (film) is d(nm).

(3) Phase difference in thickness direction (Rth)

'Rth(λ)' is the phase difference in the thickness direction measured with light having a wavelength of λ nm at 23°C. For example, 'Rth(550)' is a phase difference in the thickness direction measured with light having a wavelength of 550 nm at 23°C. Rth(λ) is obtained by the formula: Rth(λ)=(nx-nz)×d when the thickness of the layer (film) is d(nm).

(4) Nz factor

The Nz coefficient is obtained by Nz=Rth/Re.

(5) Angle

When an angle is referred to in this specification, the angle includes both clockwise and counterclockwise directions with respect to the reference direction. Thus, for example, '45°' means ±45°.

A. Overall configuration of optical film with pressure-sensitive adhesive layer

1 is a schematic cross-sectional view of an optical film with a pressure-sensitive adhesive layer according to one embodiment of the present invention. 100 A of optical films with an adhesive layer of an illustration include the polarizing plate 10, the retardation layer 20, and the adhesive layer 30 in this order from the visual recognition side. The polarizing plate 10 includes a polarizer 11, a protective layer (outer protective layer) 12 provided on the viewing side of the polarizer 11, and a protective layer (inner protective layer) provided on the opposite side of the viewing side of the polarizer 11. (13) included. The protective layer 13 may be omitted depending on the purpose or the like. For example, when the retardation layer 20 can serve as a protective layer for the polarizer 11, the protective layer 13 can be omitted.

2 is a schematic sectional view of an optical film with an adhesive layer according to another embodiment of the present invention. The optical film 100B with an adhesive layer of the illustration includes the polarizing plate 10, the retardation layer 20, and the adhesive layer 30 in this order from the visual recognition side. The polarizing plate 10 includes a polarizer 11 and an outer protective layer 12, and the inner protective layer is omitted. In this embodiment, the retardation layer 20 has a laminated structure including a first retardation layer 20a and a second retardation layer 20b, and the retardation layer 20 (substantially, the first retardation layer ( 20a)) also serves as a protective layer of the polarizer 11 . Compared to an optical film with a pressure-sensitive adhesive layer provided with an inner protective layer, the optical film with a pressure-sensitive adhesive layer in which the inner protective layer is omitted is more likely to discolor the polarizer when the retardation layer is exposed, so the effect of the present invention is more suitable. can be obtained

In the embodiment of the present invention, the vapor transmission rate of the retardation layer 20 is 300 g/m 2 24 h or more, and the end portion of the pressure-sensitive adhesive layer 30 is located inside the end portion of the polarizer 11 in cross section. Here, 'located inside' includes being in the same position, and allows the end of the pressure-sensitive adhesive layer 30 to be positioned on the same vertical line as the end of the polarizer 11 in cross-sectional view. More specifically, when the position of the end of the polarizer 11 is P ₁ and the position of the end of the pressure-sensitive adhesive layer 30 is P ₂ in cross section, P ₁ and P ₂ are on the same vertical line. or, P ₂ is located inside P ₁ , and the distance (horizontal distance) (D) between P ₁ and P ₂ is 50 μm below The distance D between P ₁ and P ₂ is preferably short, and may be 0 μm to 40 μm, 0 μm to 35 μm, 0 μm to 30 μm, or 0 μm to 25 μm _. By suppressing the exposure of the end portion of the retardation layer 20 due to lack of the pressure-sensitive adhesive layer 30 during cutting, etc., discoloration of the polarizer 11 can be suppressed even when a retardation layer having high moisture permeability is used.

The retardation layer 20 and the polarizing plate 10 are typically bonded through an adhesive layer such as an adhesive layer or a pressure-sensitive adhesive layer. In cross section, it is preferable that the edge part of the said adhesive layer is located inward rather than the edge part of a polarizer. The distance (horizontal distance) between the end of the polarizer and the end of the adhesive layer is preferably short, for example, 0 μm to 50 μm, 0 μm to 40 μm, 0 μm to 35 μm, 0 μm to 30 μm, or It may be 0 μm to 25 μm. By suppressing the exposure of the polarizing plate due to lack of the end portion of the adhesive layer or the like, the effect of suppressing discoloration of the polarizer can be more preferably obtained. Further, the ends of the protective layer and the retardation layer are preferably on the same vertical line as the ends of the polarizer in cross-sectional view.

Although not shown, it is preferable that the release film is temporarily attached to the surface of the pressure-sensitive adhesive layer until the optical film with the pressure-sensitive adhesive layer is used. Moreover, the optical film with an adhesive layer may further contain other optical function layers. The type, characteristics, number, combination, arrangement position, and the like of the optical function layers that can be provided on the optical film with a pressure-sensitive adhesive layer can be appropriately set according to the purpose.

The total thickness of the optical film with an adhesive layer is preferably 120 µm or less, more preferably 100 µm or less, still more preferably 80 µm or less. The lower limit of the total thickness may be, for example, 45 μm. An optical film with a pressure-sensitive adhesive layer having such a total thickness can contribute to thinning of the image display device and can have excellent flexibility and bending durability, so that it can be used for curved image display devices and/or It can be suitably applied to a bendable or bendable image display device.

In one embodiment, an optical film with an adhesive layer is a sheet-like film cut into predetermined dimensions. Since the optical film with an adhesive layer according to the embodiment of the present invention has little lack of an adhesive layer due to shear stress during cutting, discoloration of the polarizer end portion after being cut into sheet shape can be suppressed. As the cutting processing method, any suitable method such as punching processing, fraise processing such as pullback processing, FFC processing, and the like can be employed.

Hereinafter, the constituent elements of the optical film with a pressure-sensitive adhesive layer will be described in more detail.

B. Polarizer

B-1. polarizer

As the polarizer 11, any suitable polarizer can be employed. For example, the polarizer may be composed of a single-layer resin film, or may be obtained using a laminate of two or more layers.

Specific examples of the polarizer composed of a single-layer resin film include polyvinyl alcohol (PVA)-based resin films, partially formalized PVA-based resin films, ethylene-vinyl acetate copolymer-based partially saponified films, and the like. Polyene-based oriented films such as those to which dyeing and stretching treatment have been performed with dichroic substances such as dyes, dehydrated PVA products, and dehydrochlorinated products of polyvinyl chloride; and the like. Preferably, a polarizer obtained by uniaxially stretching a PVA-based resin film dyed with iodine is used because of its excellent optical properties.

Dyeing with the said iodine is performed by immersing a PVA-type resin film in iodine aqueous solution, for example. The draw ratio of the said uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after dyeing treatment or may be performed while dyeing. Moreover, you may dye after extending|stretching. Swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like are given to the PVA-based resin film as necessary. For example, by immersing the PVA-based resin film in water and washing it with water before dyeing, not only can dirt and antiblocking agents on the surface of the PVA-based resin film be washed, but also the PVA-based resin film can be swollen to prevent staining and the like. .

As a specific example of a polarizer obtained using a laminate, a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a resin substrate and a PVA-based resin layer coated and formed on the resin substrate. A polarizer obtained using a layered product is mentioned. A polarizer obtained by using a laminate of a resin substrate and a PVA-based resin layer coated and formed on the resin substrate is, for example, coated with a PVA-based resin solution on the resin substrate, dried to form a PVA-based resin layer on the resin substrate, and resin Obtaining a laminated body of a substrate and a PVA-based resin layer; It can be produced by extending|stretching and dyeing the said laminated body, and using a PVA system resin layer as a polarizer. In this embodiment, extending|stretching typically includes immersing a layered product in boric acid aqueous solution and extending|stretching. Further, the stretching may further include air-stretching the laminate at a high temperature (eg, 95° C. or higher) before stretching in a boric acid aqueous solution, if necessary. The obtained laminate of the resin substrate/polarizer may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), and the resin substrate is peeled from the laminate of the resin substrate/polarizer, and the peel surface is Any suitable protective layer according to may be laminated and used. The detail of the manufacturing method of such a polarizer is described in Unexamined-Japanese-Patent No. 2012-73580 and Japanese Patent No. 6470455, for example. As for these publications, the entire description is incorporated herein by reference.

The thickness of the polarizer is, for example, 25 μm or less, preferably 10 μm or less, and more preferably 8 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, and preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, still more preferably 99.9% or more.

B-2. protective layer

The outer protective layer 12 and the inner protective layer 13 (if present) are each composed of any suitable film that can be used as a protective layer of a polarizer. Examples of the material constituting the inner protective layer 13 include cycloolefin resins such as polynorbornene, (meth)acrylic resins, and polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). resins, polyolefin-based resins such as polyethylene, and polycarbonate-based resins. As a representative example of (meth)acrylic-type resin, (meth)acrylic-type resin which has a lactone ring structure is mentioned. (meth)acrylic resins having a lactone ring structure, for example, Japanese Unexamined Patent Publication No. 2000-230016, Japanese Unexamined Patent Publication No. 2001-151814, Japanese Unexamined Patent Publication No. 2002-120326, Japanese Unexamined Patent Publication No. 2002 -254544 and Japanese Unexamined Patent Publication No. 2005-146084. These publications are incorporated herein by reference. The inner protective layer 13 is preferably made of cycloolefin-based resin. Representative examples of the material constituting the outer protective layer 12 include a cellulose-based resin such as triacetyl cellulose (TAC) and a resin capable of forming a microporous film (for example, a polyurethane-based resin).

As will be described later, the optical film with a pressure-sensitive adhesive layer can be disposed on the viewing side of an image display device (typically, an organic EL display device) so that the outer protective layer is on the viewing side. Accordingly, surface treatment such as hard coat treatment, antireflection treatment, antisticking treatment, antiglare treatment, or the like may be applied to the outer protective layer as necessary. In addition,/or the outer protective layer, if necessary, a process for improving visibility when viewed through polarized sunglasses (typically, imparting a (other) circular polarization function or imparting an ultra-high phase difference) is applied. it may be By performing such a process, excellent visibility can be realized even when the display screen is visually recognized through a polarizing lens such as polarized sunglasses. Therefore, the optical film with a pressure-sensitive adhesive layer can be suitably applied also to an image display device that can be used outdoors.

The thickness of the outer protective layer is preferably 10 μm to 80 μm, more preferably 15 μm to 70 μm, still more preferably 20 μm to 50 μm. In addition, when the surface treatment is performed, the thickness of the outer protective layer is the thickness including the thickness of the surface treatment layer.

In one embodiment, the inner protective layer is preferably optically isotropic. In this specification, 'optically isotropic' means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is -10 nm to +10 nm. The thickness of the inner protective layer is preferably 10 μm to 80 μm, more preferably 20 μm to 70 μm, still more preferably 30 μm to 50 μm.

C. phase difference layer

The retardation layer 20 may be a single layer as shown in FIG. 1 . As shown in FIG. 2 , the retardation layer 20 may have a stacked structure of the first retardation layer 20a and the second retardation layer 20b, or may have a stacked structure of three or more layers.

The moisture vapor transmission rate of the retardation layer (in the case of a laminated structure, the moisture vapor transmission rate as a whole of the laminate) is, for example, 300 g/m2·24h or more, and may be, for example, 350 g/m2·24h to 700 g/m2·24h. In the case of using the retardation layer having such humidity, the effect of the present invention can be obtained suitably.

The thickness of the retardation layer (total thickness in the case of a laminated structure) can be appropriately set depending on the purpose. The thickness of the retardation layer is preferably 1 μm to 15 μm, more preferably 1 μm to 10 μm, still more preferably 2 μm to 8 μm. It is one of the features of the present invention that discoloration of the edge portion of the polarizer can be suppressed even in the case where such a thin and high water permeability retardation layer is used.

When the retardation layer 20 is a single layer, the retardation layer can typically function as a λ/4 plate. The retardation layer typically exhibits a relationship of nx>ny=nz in refractive index characteristics. The in-plane retardation Re(550) of the retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, still more preferably 120 nm to 160 nm. Also, here, 'ny=nz' includes the case where ny and nz are substantially the same as well as the case where they are completely the same. Therefore, there may be cases where ny>nz or ny<nz is satisfied within a range that does not impair the effect of the present invention.

The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. By satisfying this relationship, an organic EL display device having a very good reflective color can be obtained.

The retardation layer preferably exhibits reverse dispersion wavelength characteristics in which the retardation value increases with the wavelength of the measurement light. In this case, Re(450)/Re(550) of the retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and 0.95 or less. With such a configuration, very excellent antireflection characteristics can be realized.

The angle between the slow axis of the retardation layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, still more preferably about 45°. When the angle is within this range, an organic EL display device having very excellent antireflection properties can be obtained by using the λ/4 plate as the retardation layer as described above.

The retardation layer may be made of any suitable material as long as the above characteristics can be satisfied. Specifically, the retardation layer may be an alignment-fixed layer of a liquid crystal compound (hereinafter referred to as a liquid-crystal alignment-fixed layer) or a stretched film of a resin film.

When the retardation layer is a liquid crystal alignment solidified layer, by using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be significantly increased compared to non-liquid crystal materials, so that the thickness of the retardation layer for obtaining the desired in-plane retardation can be remarkably can be made small As a result, further thinning of the optical film with the pressure-sensitive adhesive layer (as a result, the image display device) can be realized. In this specification, the 'alignment fixed layer' refers to a layer in which liquid crystal compounds are aligned in a predetermined direction within the layer and the alignment state is fixed. In addition, the 'alignment hardened layer' is a concept including an alignment hardened layer obtained by curing a liquid crystal monomer. In this embodiment, rod-shaped liquid crystal compounds are typically aligned in a state aligned in the direction of the slow axis of the retardation layer (homogeneous alignment). The specific example of a liquid crystal compound and the detail of the formation method of a liquid crystal alignment hardening layer are described in Unexamined-Japanese-Patent No. 2006-163343 and Unexamined-Japanese-Patent No. 2006-178389, for example. The descriptions of these publications are incorporated herein by reference.

The thickness of the retardation layer composed of a single layer of the liquid crystal alignment fixed layer may be, for example, 1 μm to 5 μm.

When the retardation layer 20 has a laminated structure of the first retardation layer 20a and the second retardation layer 20b, the first retardation layer is a single layer and can function as a λ/4 plate. preferably used The angle between the slow axis of the first retardation layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, still more preferably about 45°.

The second retardation layer may be a so-called positive C plate having a refractive index characteristic of nz>nx=ny. By using the positive C plate as the second retardation layer, reflection in an oblique direction can be satisfactorily prevented, and a wide viewing angle of the anti-reflection function becomes possible. In this case, the phase difference Rth (550) in the thickness direction of the second retardation layer is preferably -50 nm to -300 nm, more preferably -70 nm to -250 nm, still more preferably -90 nm to -200 nm, particularly preferably is -100 nm to -180 nm. Here, 'nx=ny' includes not only a case where nx and ny are strictly equal, but also a case where nx and ny are substantially equal. That is, the in-plane retardation Re(550) of the second retardation layer may be less than 10 nm.

The second retardation layer having a refractive index characteristic of nz>nx=ny may be formed of any suitable material. The second retardation layer preferably includes a film containing a liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) capable of homeotropic alignment may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the retardation layer include the liquid crystal compound described in [0020] to [0028] of Japanese Unexamined Patent Publication No. 2002-333642 and the method for forming the retardation layer. In this case, the thickness of the second retardation layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, still more preferably 0.5 μm to 5 μm.

D. Adhesive layer

As the pressure-sensitive adhesive layer, a pressure-sensitive adhesive layer having relatively high elasticity and small adhesive chipping due to cutting is preferably used.

The amount of strain at a stress of 0.4 N when stress-strain measurement is performed at 23° C. of the pressure-sensitive adhesive layer is, for example, 900% or less, preferably 800% or less, more preferably 200% to 600%, still more preferably It is 200% - 400%.

The creep value of the pressure-sensitive adhesive layer at 85°C may be preferably 80 μm or less, more preferably 1 μm to 60 μm, still more preferably 1 μm to 50 μm. The creep value can be measured by the method described in Examples.

The storage modulus (G′) of the pressure-sensitive adhesive layer at 25° C. is preferably 1.00 × 10 ⁵ Pa or more, more preferably 1.10 × 10 ⁵ Pa or more, and more preferably 2.00 × 10 ⁶ Pa or less. there is.

The storage modulus (G') of the pressure-sensitive adhesive layer at 85°C is preferably 7.00 × 10 ⁴ (Pa) or more, more preferably 1.00 × 10 ⁵ Pa or more, still more preferably 1.50 × 10 ⁵ Pa or more. , and preferably may be 5.50×10 ⁶ Pa or less.

The moisture permeability of the pressure-sensitive adhesive layer is, for example, 2500 g/m 2 24 h or less, preferably 100 g/m 2 24 h to 2000 g/m 2 24 h.

The thickness of the pressure-sensitive adhesive layer is, for example, 5 μm to 50 μm, preferably 5 μm to 35 μm, and more preferably 5 μm to 25 μm.

Examples of the adhesive forming the pressure-sensitive adhesive layer include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, vinylalkyl ether-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, and the like. An adhesive base polymer is selected according to the type of adhesive. Among the pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because of their excellent optical transparency and adhesive properties.

The acrylic pressure sensitive adhesive contains a (meth)acrylic polymer as a base polymer. A (meth)acrylic polymer usually contains an alkyl (meth)acrylate as a main component as a monomer unit. In addition, (meth)acrylate means acrylate and/or methacrylate, and has the same meaning as (meth) in this specification.

Examples of the alkyl (meth)acrylates constituting the main skeleton of (meth)acrylic polymers include straight-chain or branched-chain alkyl groups having 1 to 18 carbon atoms. These may be used alone or in combination. The average carbon number of these alkyl groups is preferably 3 to 9.

In addition, from the viewpoint of adhesive properties, durability, adjustment of phase difference, adjustment of refractive index, etc., an aromatic ring-containing alkyl (meth)acrylate such as phenoxyethyl (meth)acrylate or benzyl (meth)acrylate is used as a copolymerization monomer. can be used as

Among the (meth)acrylic polymers, for the purpose of improving adhesion and heat resistance, one or more copolymerizable monomers having a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group may be introduced by copolymerization. can Specific examples of such a copolymerization monomer include, for example, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate. , hydroxyl groups such as 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methylacrylate. containing monomers; carboxyl group-containing monomers such as (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; Styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide 2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl(meth)acrylate, (meth)acryloyloxynaphthalenesulfonic acid, etc. of a sulfonic acid group-containing monomer; Phosphoric acid group containing monomers, such as 2-hydroxyethyl acryloyl phosphate, etc. are mentioned.

In addition, (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylolpropane (meth)acrylamide, etc. (N-substituted) amide-based monomers; (meth)acrylic acid alkylaminoalkyl type monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; alkoxyalkyl (meth)acrylate monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyoctamethylenesuccinimide, N -Succinimide type monomers such as acryloylmorpholine; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide Itaconimide type monomers, such as mead and N-lauryl itaconimide, etc. are also mentioned as a copolymerization monomer.

In addition, as other copolymerization monomers, vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimida vinyl monomers such as sol, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate-based monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; Acrylic acid ester type monomers, such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate, and 2-methoxyethyl acrylate, etc. can also be used. Furthermore, isoprene, butadiene, isobutylene, vinyl ether, etc. are mentioned.

Moreover, as a copolymerization monomer other than the above, the silane type monomer containing a silicon atom, etc. are mentioned. Examples of the silane-based monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyl Octyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltrie Toxysilane, 10-acryloyloxydecyl triethoxysilane, etc. are mentioned.

Further, as copolymerizable monomers, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diglycidyl ether di(meth) Acrylates, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate ) (meth)acryloyl groups such as esters of (meth)acrylic acid and polyhydric alcohols such as acrylate, dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate, vinyl A multifunctional monomer containing two or more unsaturated double bonds such as a group, or a functional group similar to a monomer component in the backbone of polyester, epoxy, urethane, etc. Two unsaturated double bonds such as (meth)acryloyl group and vinyl group Polyester (meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, etc. added above can also be used.

The (meth)acrylic polymer has an alkyl (meth)acrylate as a main component in terms of the weight ratio of all constituent monomers, and the ratio thereof is preferably 70% by weight to 99.9% by weight, more preferably 75% by weight to 99% by weight. It is preferable, and 80 weight% - 98 weight% are more preferable. By using an alkyl (meth)acrylate as a main component, a pressure-sensitive adhesive having excellent adhesive properties can be obtained.

The weight ratio of the copolymerization monomer in all constituent monomers is preferably from 0.1% by weight to 30% by weight, more preferably from 1% by weight to 25% by weight, and further from 2% by weight to 30% by weight, based on the weight ratio of all constituent monomers. It is desirable to be

Among these copolymerization monomers, a hydroxyl group-containing monomer and a carboxyl group-containing monomer are preferably used from the viewpoint of adhesiveness and durability. A hydroxyl group-containing monomer and a carboxyl group-containing monomer can be used together. These copolymerization monomers serve as reaction sites with the crosslinking agent when the pressure-sensitive adhesive contains the crosslinking agent. Since hydroxyl group-containing monomers, carboxyl group-containing monomers, and the like are highly reactive with intermolecular crosslinking agents, they are preferably used for improving the cohesiveness and heat resistance of the resulting pressure-sensitive adhesive layer.

As the copolymerization monomer, when a hydroxyl group-containing monomer is contained, the ratio thereof is preferably 0.01% by weight to 15% by weight, more preferably 0.05% by weight to 10% by weight, still more preferably 0.1% by weight to 5% by weight do. In addition, when containing a carboxyl group-containing monomer as a copolymerization monomer, the ratio is preferably 0.01% by weight to 15% by weight, more preferably 0.05% by weight to 10% by weight, and even more preferably 0.1% by weight to 5% by weight. desirable.

The weight average molecular weight of the (meth)acrylic polymer is, for example, 1 million to 2.5 million, preferably 1.2 million to 2.3 million. A weight average molecular weight of 1,000,000 or more is preferred from the viewpoint of heat resistance. Moreover, when a weight average molecular weight becomes larger than 2.5 million, an adhesive may become hard. In addition, a weight average molecular weight is measured by GPC (gel permeation chromatography) and calculated|required from the value computed by polystyrene conversion.

For production of such a (meth)acrylic polymer, known production methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations can be appropriately selected. In addition, any, such as a random copolymer, a block copolymer, and a graft copolymer, may be sufficient as the (meth)acrylic polymer obtained.

Further, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer may contain a crosslinking agent depending on the base polymer. As the base polymer, for example, when a (meth)acrylic polymer is used, an organic crosslinking agent or a polyfunctional metal chelate can be used as the crosslinking agent. As an organic type crosslinking agent, an isocyanate type crosslinking agent, a peroxide type crosslinking agent, an epoxy type crosslinking agent, an imine type crosslinking agent, etc. are mentioned. A polyfunctional metal chelate is one in which a multivalent metal is bonded covalently or coordinately to an organic compound. Examples of the multivalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. there is. An oxygen atom etc. are mentioned as an atom in the organic compound which forms a covalent bond or coordinate bond, and an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, a ketone compound etc. are mentioned as an organic compound.

The amount of the crosslinking agent is preferably from 0.5 parts by weight to 6 parts by weight, more preferably from 1 part by weight to 6 parts by weight, more preferably from 2 parts by weight to 5.5 parts by weight, and more preferably from 3 parts by weight to 100 parts by weight of the (meth)acrylic polymer. Part to 5 parts by weight is still more preferred.

A silane coupling agent and other additives can be contained in the adhesive which forms an adhesive layer. For example, polyether compounds of polyalkylene glycol such as polypropylene glycol, colorants, powders such as pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, reducing agents, anti-aging agents, Light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particulates, thin materials and the like can be appropriately added depending on the use. These additives are preferably used in a range of 5 parts by weight or less, further 3 parts by weight or less, and further 1 part by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer.

E. Image display device

The said optical film with an adhesive layer can be applied to image display apparatuses, such as an organic electroluminescent display apparatus and a liquid crystal display apparatus. Therefore, embodiment of this invention includes the image display apparatus provided with the said optical film with an adhesive layer. When an image display device is an organic electroluminescent display device, the said optical film with an adhesive layer is laminated|stacked on the visual recognition side of an organic electroluminescent cell so that a retardation layer may become the organic electroluminescent cell side.

[Example]

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited by these examples. The measurement method of each characteristic is as follows. In addition, unless otherwise specified, 'parts' and '%' in Examples and Comparative Examples are based on weight.

(1) Thickness

The thickness of 10 µm or less was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name 'MCPD-3000'). The thickness exceeding 10 µm was measured using a digital micrometer (manufactured by Anritz Corporation, product name 'KC-351C').

(2) Stress-strain measurement

The pressure-sensitive adhesive solution was casted and applied onto the release-treated surface of a polyethylene terephthalate film (thickness: 38 μm) subjected to release treatment on one side so that the thickness after drying was about 4 μm, and heated to 130 ° C. After heat-drying for 3 minutes and further aging at 50°C for 24 hours, what was formed into a cylindrical shape with a cross-sectional area of 1 mm 2 was used as a sample. The maximum stress (N /mm ² ) and maximum elongation (%) were measured.

(3) Permeability

A sample in which a retardation layer (a laminate of the first retardation layer and the second retardation layer) was bonded to a TAC film having a thickness of 25 μm through an adhesive was measured according to JIS Z 0208 (cup method) as a measurement sample.

(4) Creep value

An optical film with an adhesive layer was cut out to a size of 10 mm x 30 mm to make a test sample. An upper end of 10 mm × 10 mm of the test sample was adhered to a SUS plate via an adhesive layer, and autoclave treatment was performed for 15 minutes under conditions of 50°C and 5 atmospheric pressure. A precision hot plate installed so that the heating surface is in the vertical direction was heated to 85 ° C., and the SUS plate to which the optical film with the adhesive layer was attached was installed so that the surface without the adhesive layer was in contact with the heating surface of the hot plate. . After heating the SUS board at 85°C for 5 minutes, a load of 500 gf was applied vertically downward to the lower end of the polarizing film with an adhesive layer. Attachment of the adhesive layer after 1 second and 3600 seconds after applying a load The amount of shift between the optical film and the SUS plate was measured, and it was set as Cr ₁ and Cr ₃₆₀₀ , respectively. ΔCr calculated by the following formula from Cr ₁ and Cr ₃₆₀₀ was used as the creep value.

ΔCr=Cr ₃₆₀ -Cr ₁

(5) Storage modulus

A test sample having a thickness of about 1.5 mm was prepared by peeling the release film from the pressure-sensitive adhesive layer produced in the production example and laminating a plurality of pressure-sensitive adhesive layers. This test sample was punched into a disk shape with a diameter of 7.9 mm, inserted into a parallel plate, and dynamic viscoelasticity was measured under the following conditions using the "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific. The storage modulus (G') was read from the results.

(Measuring conditions)

Deformation Mode: Torsion

Measurement temperature: -40°C to 150°C

Heating rate: 5°C/min

Measurement frequency: 1Hz

(6) single transmittance

Regarding the polarizing plate having the configuration of [polarizer / protective layer], the transmittance (Ts) at a wavelength of 380 nm to 780 nm when measured using an ultraviolet / visible / near infrared spectrophotometer (V-7100 manufactured by Nippon Spectroscopy Co., Ltd.), It was set as the single transmittance (Ts) of the polarizer. This Ts is a Y value obtained by performing visibility correction by measuring with a 2-degree field of view (C light source) of JIS Z8701.

[Production Example 1: Production of pressure-sensitive adhesive layer A]

1. Preparation of adhesive

In a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirring device, 94.9 parts of butyl acrylate, 5 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate and 0.3 part of 2,2'-azobisisobutyronitrile were added. Part was added together with ethyl acetate to prepare a solution. Subsequently, the solution was stirred while blowing nitrogen gas into the solution and reacted at 55°C for 8 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight of 2.1 million. Furthermore, ethyl acetate was added to the solution containing this acrylic polymer to obtain an acrylic polymer solution in which the solid content concentration was adjusted to 30%.

Based on 100 parts of the solid content of the acrylic polymer solution, a crosslinking agent mainly composed of a compound having an isocyanate group (manufactured by Nippon Polyurethane Co., Ltd., trade name 'Coronate L') and 0.2 part of an epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.) , trade name 'KBM-403') were blended in this order to prepare an adhesive solution.

2. Production of adhesive layer

The pressure-sensitive adhesive solution was applied to the surface of a release film made of a polyethylene terephthalate film (thickness: 38 μm) subjected to release treatment, and dried to a thickness of 20 μm after drying to prepare an adhesive layer A.

[Production Example 2: Production of PSA Layer B]

Pressure-sensitive adhesive layer B was prepared in the same manner as in Production Example 1 except that the addition amount of the crosslinking agent (manufactured by Nippon Polyurethane Co., trade name 'Coronate L') was 0.6 parts and the pressure-sensitive adhesive solution was applied so that the thickness after drying was 15 μm. produced.

[Production Example 3: Production of Pressure-sensitive Adhesive Layer C]

A solution containing an acrylic polymer having a weight average molecular weight of 1.8 million was obtained using 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate as monomer components, and 0.1 part of trimethylolpropane/xylenediisocyanate adduct as a crosslinking agent ( Manufacturing example, except that Tosoh Corporation, trade name 'Takenate D110N') and 0.3 part peroxide crosslinking agent (Nipper Oil, trade name 'Nipper BMT') were used, and the adhesive solution was applied so that the thickness after drying was 15 μm. It carried out similarly to 1, and produced the adhesive layer C.

[Production Example 4: Production of Pressure-Sensitive Adhesive Layer D]

As a monomer component, a solution containing an acrylic polymer having a weight average molecular weight of 1.8 million was obtained using 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate, and 0.02 part of trimethylolpropane/xylylenediisocyanate adduct as a crosslinking agent (manufactured by Tosoh Corporation, trade name 'Takenate D110N') and 0.3 part peroxide crosslinking agent (manufactured by Nippon Oil Co., Ltd., trade name 'Nyper BMT'), and applied with an adhesive solution so that the thickness after drying is 21 μm Manufactured It carried out similarly to Example 1, and produced the adhesive layer D.

[Production Example 5: Production of Pressure-Sensitive Adhesive Layer E]

A pressure-sensitive adhesive layer E (thickness: 30 µm) was obtained in the same manner as in Production Example 3 except that the pressure-sensitive adhesive solution was applied so that the thickness of the obtained pressure-sensitive adhesive layer was 30 µm.

Viscoelasticity was measured using the pressure-sensitive adhesive layers A to D prepared in Production Examples 1 to 4. Moreover, the creep value of the adhesive layer was evaluated using the optical film with an adhesive layer (the optical film with an adhesive layer obtained in Examples 1-4 below) provided with adhesive layers A-D. The results are shown in Table 1.

[Table 1]

[Example 1]

1. Fabrication of polarizer

As the thermoplastic resin base material, an amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) was used, which was long and had a water absorption of 0.75% and a Tg of about 75°C. Corona treatment was performed on one side of the resin substrate.

100 parts by weight of a PVA-based resin obtained by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: 'Kose Pharma Z410') at a ratio of 9:1, potassium iodide Added 13 parts by weight was dissolved in water to prepare a PVA aqueous solution (coating liquid).

A PVA-based resin layer having a thickness of 13 μm was formed by applying the PVA aqueous solution to the corona-treated surface of the resin substrate and drying at 60° C., thereby producing a laminate.

The obtained layered product was uniaxially stretched at the free end by 2.4 times in the machine direction (longitudinal direction) between rolls having different circumferential speeds in a 130°C oven (air assisted stretching treatment).

Next, the laminate was immersed in an insolubilization bath (boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insolubilization treatment).

Subsequently, the dyeing bath (iodine concentration is 0.03% by weight and potassium concentration is 0.2% by weight of iodine solution) with a liquid temperature of 30 ° C., and the polarizer finally obtained has a single transmittance (Ts) of 42.0%. It was immersed for 60 seconds while adjusting the concentration so that it became (dyeing treatment).

Next, it was immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment).

Thereafter, the laminate was immersed in an aqueous solution of boric acid at a liquid temperature of 70°C (boric acid concentration: 4.0% by weight, potassium iodide: 5.0% by weight), while the total draw ratio was increased by 5.5 times in the machine direction (longitudinal direction) between rolls having different circumferential speeds. Uniaxial stretching was performed as much as possible (underwater stretching treatment).

Thereafter, the laminate was immersed in a washing bath (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 20°C (washing treatment).

Thereafter, while drying in an oven maintained at 90°C, it was brought into contact with a heating roll made of SUS whose surface temperature was maintained at 75°C for about 2 seconds (dry shrinkage treatment). The shrinkage rate in the width direction of the layered product by the drying shrinkage treatment was 5.2%.

In this way, a polarizer having a thickness of 5 μm was formed on the resin substrate.

2. Fabrication of polarizer

The HC-TAC film was bonded to the polarizer surface of the [resin base material/polarizer] laminate obtained above through a PVA-based resin aqueous solution. Specifically, a PVA-based resin aqueous solution (manufactured by Nippon Synthetic Chemical Industries, Ltd., trade name "Gose Famer (registered trademark) Z-200", resin concentration: 3% by weight) was applied, an HC-TAC film was bonded, and 60 ° C. It was bonded by heating for 5 minutes in an oven maintained at . In addition, the HC-TAC film is a film in which a hard coat (HC) layer (thickness of 7 μm) is formed on a triacetyl cellulose (TAC) film (thickness of 25 μm), and the TAC film is bonded with the polarizer side. Then, the resin substrate was peeled off to obtain a polarizing plate having a configuration of [outer protective layer (HC-TAC film)/polarizer].

3. Fabrication of the first retardation layer

After adding 55 parts of the compound represented by formula (I), 25 parts of the compound represented by formula (II), and 20 parts of the compound represented by formula (III) to 400 parts of cyclopentanone (CPN), heated to 60 ° C. and stirred to dissolve After dissolution was confirmed, it was returned to room temperature, 3 parts of Irgacure 907 (manufactured by BASF Japan Co., Ltd.), Megapack F-554 (manufactured by DIC Co., Ltd.) 0.2 part, p-methoxyphenol ( MEHQ) was added, and further stirring was performed to obtain a solution. The solution was clear and homogeneous. The resulting solution was filtered through a 0.20 μm membrane filter to obtain a polymerizable composition. On the other hand, a polyimide solution for an alignment film was applied to a glass substrate having a thickness of 0.7 mm by spin coating, dried at 100°C for 10 minutes, and then baked at 200°C for 60 minutes to obtain a coating film. The obtained coating film was rubbed to form an alignment film. The rubbing treatment was performed using a commercially available rubbing device. The polymerizable composition obtained above was applied to a substrate (substantially an alignment film) by spin coating, and dried at 100°C for 2 minutes. After cooling the obtained coating film to room temperature, ultraviolet-ray was irradiated for 30 second at the intensity|strength of 30 mW/cm<2> using the high-pressure mercury lamp, and the liquid crystal alignment hardening layer (2.8 micrometers in thickness) was obtained. The in-plane retardation Re (550) of the liquid crystal alignment hardened layer was 130 nm. In addition, Re(450)/Re(550) of the liquid crystal alignment hardening layer was 0.851, and exhibited reverse dispersion wavelength characteristics.

4. Fabrication of the second retardation layer

20 parts by weight of a side chain type liquid crystal polymer represented by the following formula (IV) (numbers 65 and 35 in the formula represent the mole% of the monomer unit and are conveniently represented as block polymers: weight average molecular weight 5000), representing a nematic liquid crystal phase A liquid crystal coating solution was prepared by dissolving 80 parts by weight of a polymerizable liquid crystal (manufactured by BASF: trade name Paliocolor LC242) and 5 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: trade name Irgacure 907) in 200 parts by weight of cyclopentanone. Then, the liquid crystal was aligned by applying the coating liquid to a base film (norbornene-based resin film: manufactured by Nippon Zeon Co., Ltd., trade name “Zeonex”) with a bar coater and then heating and drying at 80° C. for 4 minutes. The liquid crystal layer was irradiated with ultraviolet rays to cure the liquid crystal layer, thereby forming an alignment hardened layer of liquid crystal compounds (liquid crystal alignment hardened layer, thickness: 0.58 μm) serving as the second retardation layer on the substrate. Re (590) of this layer was 0 nm, Rth (590) was -100 nm, and the refractive index characteristic of nz > nx = ny was exhibited.

5. Production of optical film with pressure-sensitive adhesive layer

The 1st retardation layer was bonded to the polarizer surface of the polarizing plate obtained in 2. via the adhesive (5 micrometers in thickness), and the glass base material was peeled. Here, it bonded so that the angle of the absorption axis of a polarizer and the slow axis of a 1st retardation layer might become +45 degree. Subsequently, the second phase difference layer was bonded to the surface of the first phase difference layer through a UV curable adhesive (thickness: 1 µm), and the base film was peeled off. Further, the pressure-sensitive adhesive layer A prepared in Production Example 1 was bonded to the surface of the second phase difference layer. Thus, an optical film with an adhesive layer having a configuration of [protective layer / polarizer / first retardation layer / second retardation layer / adhesive layer A (/ release film)] (actually, a circular polarizing plate with an adhesive layer) was obtained.

[Example 2]

Except for using the pressure-sensitive adhesive layer B instead of the pressure-sensitive adhesive layer A, in the same manner as in Example 1, [protective layer / polarizer / first retardation layer / second phase difference layer / pressure-sensitive adhesive layer B (/ release film)]. An adhesive optical film was obtained.

[Comparative Example 1]

Except for using the pressure-sensitive adhesive layer C instead of the pressure-sensitive adhesive layer A, in the same manner as in Example 1, [protective layer / polarizer / first phase difference layer / second phase difference layer / pressure-sensitive adhesive layer C (/ release film)]. An adhesive optical film was obtained.

[Comparative Example 2]

A pressure-sensitive adhesive layer having a configuration of [protective layer / polarizer / first retardation layer / second retardation layer / pressure-sensitive adhesive layer D (/ release film)] in the same manner as in Example 1 except that the pressure-sensitive adhesive layer D was used instead of the pressure-sensitive adhesive layer A. An adhesive optical film was obtained.

[Comparative Example 3]

Except for using the pressure-sensitive adhesive layer E instead of the pressure-sensitive adhesive layer A, in the same manner as in Example 1, [protective layer / polarizer / first phase difference layer / second phase difference layer / pressure-sensitive adhesive layer E (/ release film)]. An adhesive optical film was obtained.

[Reference Example 1]

1. Fabrication of polarizer

A polarizer having a thickness of 5 μm was formed on a resin substrate in the same manner as in Example 1 except that the iodine concentration of the dyeing bath was 0.025% by weight and the potassium concentration was 0.18% by weight.

2. Fabrication of polarizer

A polarizing plate having a configuration of [outer protective layer (HC-TAC film)/polarizer] was obtained in the same manner as in Example 1 except that the laminate of [resin substrate/polarizer] obtained above was used.

3. Production of retardation film constituting the retardation layer

3-1. Polymerization of polyester carbonate resin

Polymerization was carried out using a batch polymerization apparatus including two vertical reactors equipped with stirring blades and a reflux condenser controlled at 100°C. Bis [9- (2-phenoxycarbonylethyl) fluoren-9-yl] methane 29.60 parts by mass (0.046 mol), isosorbide (ISB) 29.21 parts by mass (0.200 mol), spiroglycol (SPG) 42.28 mass part (0.139 mol), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19 x 10 ^-2 parts by mass (6.78 x 10 ^-5 mol) of calcium acetate monohydrate as a catalyst. After replacing the inside of the reactor with reduced pressure nitrogen, heating was performed with a heat medium, and stirring was started when the internal temperature reached 100°C. The internal temperature reached 220 ° C. after 40 minutes from the start of the temperature rise, and while controlling to maintain this temperature, the pressure reduction was started, and after reaching 220 ° C., it was set to 13.3 kPa in 90 minutes. Phenol vapor produced as a byproduct of the polymerization reaction was directed to a reflux condenser at 100° C., a small amount of the monomer component contained in the phenol vapor was returned to the reactor, and uncondensed phenol vapor was directed to a condenser at 45° C. for recovery. After nitrogen was introduced into the first reactor to once restore the pressure to atmospheric pressure, the oligomerized reaction solution in the first reactor was transferred to the second reactor. Subsequently, the temperature increase and pressure reduction in the second reactor were started, and the internal temperature was 240°C and the pressure was 0.2 kPa in 50 minutes. Thereafter, polymerization was allowed to proceed until a predetermined agitation power was reached. At the time of reaching the predetermined power, nitrogen was introduced into the reactor to restore pressure, the resulting polyester carbonate-based resin was extruded into water, and the strand was cut to obtain pellets.

3-2. Production of retardation film

After melt-kneading 0.7 parts by mass of PMMA to the obtained polyester carbonate-based resin (pellet) and vacuum drying at 80 ° C. for 5 hours, a single screw extruder (manufactured by Toshiba Machinery Co., Ltd., cylinder set temperature: 250 ° C.), T die (width 200 mm, set temperature: 250 ° C.), a cooling roll (set temperature: 120 to 130 ° C.), and a film forming apparatus equipped with a winding machine were used to produce a long resin film with a thickness of 130 μm. The obtained elongated resin film was stretched while adjusting so as to obtain a predetermined phase difference, and a phase difference film having a thickness of 38 µm was obtained. The stretching conditions were a stretching temperature of 143°C and a stretching ratio of 2.8 times in the width direction. Re(550) of the obtained retardation film was 141 nm, Re(450)/Re(550) was 0.86, and the Nz coefficient was 1.12.

4. Preparation of optical film with pressure-sensitive adhesive layer

Retardation film was bonded to the polarizer surface of the polarizing plate obtained in 2. via an adhesive (thickness: 5 µm). Here, it bonded so that the angle of the absorption axis of a polarizer and the slow axis of retardation film might become +45 degrees. Subsequently, the pressure-sensitive adhesive layer E prepared in Production Example 5 was transferred to the surface of the retardation film. Thereby, the optical film with the adhesive layer which has the structure of [protective layer / polarizer / retardation layer / adhesive layer E (/peeling film)] was obtained.

<Cutting process>

A laminate obtained by laminating a surface protection film (manufactured by Nitto Denko, trade name "PPF-100T") on the TAC film side with HC of the optical film with an adhesive layer obtained in Examples, Comparative Examples, and Reference Examples was used as a workpiece, The cross section of each of the four sides of the rectangle was cut and polished by 2.5 mm with a pullback cutter under the following conditions, and cut into a rectangular shape with a size of 25 mm × 50 mm.

[Processing conditions]

Revolutions/feed rate: 4500 rpm/900 mm/min

The obtained rectangular optical film with a pressure-sensitive adhesive layer was cut in the thickness direction, and its cross section was observed at a magnification of 10 times using an optical microscope (MX61L, manufactured by Olympus), and the position P ₂ of the end of the pressure-sensitive adhesive layer and the end of the polarizer were observed. The horizontal distance (the amount of adhesive deficiency) of the position P ₁ was measured. The results are shown in Table 2.

<Hot water test>

The peeling film was peeled from the rectangular optical film with an adhesive layer obtained by the cutting process, and the adhesive layer was exposed. The optical film with the pressure-sensitive adhesive layer was bonded to the glass plate through the pressure-sensitive adhesive layer, and was immersed in 60°C warm water for 30 minutes. The optical film with the pressure-sensitive adhesive layer after immersion was observed under a microscope, and the depth (amount of discoloration) of the region where discoloration occurred was measured on the basis of the end portion of the polarizer. In addition, in consideration of the practical acceptable range of the bleaching amount, the case where the amount of bleaching was 250 μm or less was evaluated as “good” and the case exceeding 250 μm was evaluated as “poor”. The results are shown in Table 2.

[Table 2]

As shown in Table 2, in the reference example where the water vapor transmission rate of the retardation layer is small, the discoloration of the polarizer is within a practically allowable range even if the amount of adhesive deficiency is large, but the water vapor transmission rate of the retardation layer is large and the amount of adhesive deficiency is also large. In a comparative example, The amount of decolorization of the polarizer was large. On the other hand, in Examples with a small amount of adhesive deficiency, discoloration of the polarizer was suppressed within a practically allowable range even if the water vapor transmission rate of the retardation layer was large.

The optical film with a pressure-sensitive adhesive layer of the present invention is suitably used as a circularly polarizing plate for image display devices such as a liquid crystal display device, an organic EL display device, and an inorganic EL display device.

10: polarizer
11: polarizer
12: outer protective layer
13: inner protective layer
20: phase difference layer
30: adhesive layer
100: optical film with adhesive layer

Claims (7)

A polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer, a retardation layer, and an adhesive layer are provided in this order from the viewing side,
The moisture permeability of the retardation layer is 300 g / m 2 24 h or more,
An optical film with a pressure-sensitive adhesive layer in which, in a sectional view, an end portion of the pressure-sensitive adhesive layer is located inside an end portion of the polarizer, and a horizontal distance between an end portion of the pressure-sensitive adhesive layer and an end portion of the polarizer is 0 μm to 50 μm. . The optical film with an adhesive layer according to claim 1, wherein the polarizing plate includes the polarizer and a protective layer arranged only on the viewing side of the polarizer. The optical film with an adhesive layer of Claim 1 or 2 whose thickness of the said polarizer is 10 micrometers or less. The optical film with an adhesive layer according to any one of claims 1 to 3, wherein the amount of strain at a stress of 0.4 N when the stress-strain measurement is performed at 23°C of the pressure-sensitive adhesive layer is 900% or less. According to any one of claims 1 to 4,
The retardation layer includes an orientation hardening layer of a liquid crystal compound,
Re (550) and Re (450) of the alignment hardening layer of the liquid crystal compound satisfy the relationship of 0.8 ≤ Re (450) / Re (550) < 1,
Re (550) of the alignment hardening layer of the liquid crystal compound is 100 nm to 190 nm,
The optical film with an adhesive layer whose angle which the slow axis of the orientation hardening layer of the said liquid crystal compound and the absorption axis of the said polarizer make is 40 degrees - 50 degrees. An image display device provided with the optical film with an adhesive layer according to any one of claims 1 to 5. The image display device according to claim 6, which is an organic electroluminescence display device.