CN117849929A

CN117849929A - Laminate and image display device

Info

Publication number: CN117849929A
Application number: CN202311120929.3A
Authority: CN
Inventors: 藤田雅人
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2022-10-04
Filing date: 2023-09-01
Publication date: 2024-04-09
Also published as: JP2024054012A; KR20240047313A

Abstract

Provided is a laminate which is thin and has excellent durability. The laminate of the embodiment of the present invention comprises a polarizer, a first adhesive layer, and a resin layer disposed between the polarizer and the first adhesive layer, wherein the polarizer is disposed adjacent to the resin layer, and the resin layer comprises a polymer having a glass transition temperature of 85 ℃ or higher and a weight averageA resin having a molecular weight Mw of 25000 or more, wherein the first adhesive layer has a thickness of 25 [ mu ] m or less and a storage modulus at-25 ℃ of 6.5X10 ⁶ Pa or more.

Description

Laminate and image display device

Technical Field

The present invention relates to a laminate and an image display device.

Background

Image display devices typified by liquid crystal display devices and Electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices) are rapidly spreading. In an image display panel mounted on an image display device, a polarizing plate is generally used. Typically, a laminate in which a retardation layer and a polarizing plate are integrated is widely used (for example, patent document 1). In recent years, there has been a strong demand for a thinner image display device, and there has also been a strong demand for a thinner laminate.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2022-0133705

Disclosure of Invention

Problems to be solved by the invention

With the thickness reduction of the laminate, the durability of the laminate may not be sufficiently ensured. For example, in the process of manufacturing an image display panel, cracks may occur in the laminate.

The present invention has been made in view of the above-described problems, and a main object thereof is to provide a laminate which is thin and has excellent durability.

Means for solving the problems

1. The laminate according to the embodiment of the present invention comprises: a polarizer including a polarizer; a first adhesive layer; and a resin layer disposed between the polarizer and the first adhesive layer, the polarizer being disposed adjacent to the resin layer, the resin layer including a resin having a glass transition temperature of 85 ℃ or higher and a weight average molecular weight Mw of 25000 or higher, the first adhesive layer having a thickness of 25 μm or less and a storage modulus at-25 ℃ of 6.5X10 ⁶ Pa or more.

2. The laminate according to the above 1, wherein the first adhesive layer may contain an antistatic agent. The antistatic agent may be an ionic compound having a melting point of 23℃or higher.

3. The laminate according to the above 2, wherein the anion constituting the ionic compound may be bis (trifluoromethanesulfonyl) imide anion.

4. The laminate according to the above 2 or 3, wherein the ionic compound may be an alkali metal salt.

5. The laminate according to the above 4, wherein the alkali metal salt may be a lithium salt.

6. The laminate according to any one of the above 2 to 5, wherein the content of the antistatic agent may be 3 parts by weight or less relative to 100 parts by weight of the base polymer of the first adhesive layer.

7. The laminate according to any one of the above 2 to 6, wherein the surface resistivity of the first adhesive layer may be 9X 10 ¹¹ Ω/≡or less.

8. The laminate according to any one of the above 1 to 7 may further comprise a retardation layer which is disposed between the resin layer and the first pressure-sensitive adhesive layer and which includes at least a first retardation layer. The thickness of the laminated portion from the polarizing plate to the retardation layer may be 120 μm or less.

9. The laminate according to the above 8, wherein the first retardation layer may be a stretched film of a resin film.

10. The laminate according to 8 or 9, wherein the thickness of the first retardation layer may be 10 μm or more.

11. The laminate according to any one of 8 to 10, wherein Re (550) of the first retardation layer may be 100nm to 190nm, and Re (450)/Re (550) may be 0.8 or more and less than 1.

12. An image display device according to another embodiment of the present invention has the laminate according to any one of 1 to 11.

13. An organic EL display device according to still another embodiment of the present invention has the laminate according to any one of 1 to 11.

14. The organic EL display device according to item 13, wherein the laminate may have a profile-processed portion.

15. A method for manufacturing an image display device according to still another embodiment of the present invention includes: preparing the laminate of any one of 1 to 11 above; and attaching the laminate to an image display panel body.

Effects of the invention

According to the embodiment of the present invention, a laminate which is thin and excellent in durability can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing a schematic configuration of a laminate according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view showing a schematic configuration of an image display panel according to an embodiment of the present invention.

Fig. 3 is a diagram for explaining the procedure of the guitar pick test.

Fig. 4 is a cross-sectional SEM observation photograph showing a state where a crack is generated.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. For the sake of clarity of the description, the drawings may schematically show the width, thickness, shape, etc. of each part as compared with the embodiments, but are merely examples and do not limit the explanation of the present invention. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and duplicate descriptions may be omitted. In addition, in the present specification, (meth) acrylic refers to acrylic acid and/or methacrylic acid.

(definition of terms and marks)

The definitions of terms and notations in this specification are as follows.

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

"nx" is the refractive index in the direction in which the refractive index in the plane is largest (i.e., the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction.

(2) In-plane phase difference (Re)

"Re (λ)" is the in-plane retardation measured by light of wavelength λnm at 23 ℃. For example, "Re (550)" is the in-plane retardation measured by light having a wavelength of 550nm at 23 ℃. Re (λ) is represented by the formula: re (λ) = (nx-ny) ×d.

(3) Retardation in thickness direction (Rth)

"Rth (λ)" is a phase difference in the thickness direction measured by light having a wavelength of λnm at 23 ℃. For example, "Rth (550)" is a phase difference in the thickness direction measured by light having a wavelength of 550nm at 23 ℃. Rth (λ) is represented by the formula: rth (λ) = (nx-nz) ×d.

(4) Nz coefficient

The Nz coefficient is obtained from nz=rth/Re.

(5) Angle of

In the present specification, when referring to an angle, the angle includes both clockwise and counterclockwise with respect to a reference direction. Thus, for example, "45" refers to 45 ° clockwise and 45 ° counterclockwise.

A. Laminate body

Fig. 1 is a schematic cross-sectional view showing a schematic configuration of a laminate according to an embodiment of the present invention. The laminate 100 has a polarizing plate 10, a resin layer 20, and a first adhesive layer 31 in this order from the upper side of fig. 1. The laminate 100 further includes a retardation layer 40 disposed between the resin layer 20 and the first adhesive layer 31, and the retardation layer 40 is disposed on the resin layer 20 via the second adhesive layer 32. The laminate 100 may be referred to as a polarizing plate with a retardation layer.

The polarizing plate 10 includes a polarizer 11 having a first main surface 11a and a second main surface 11b facing each other, and a protective layer 12 disposed on the first main surface 11a side of the polarizer 11. In the illustrated example, no protective layer is disposed between the polarizer 11 and the resin layer 20, and the resin layer 20 is disposed adjacent to the polarizer 11. By omitting the protective layer in this manner, the thickness of the laminate can be reduced. The resin layer 20 can reduce the influence of the polarizer 11 on other components, for example. The laminate 100 is typically used in an image display device in which the polarizer 11 is disposed on the viewing side (also referred to as the visible side) of the resin layer 20.

The retardation layer 40 has a laminated structure including a first retardation layer 41 and a second retardation layer 42. Unlike the illustrated example, the retardation layer 40 may have a laminated structure of three or more layers, or may be a single layer.

The laminate (polarizing plate with retardation layer) 100 may further have other functional layers not shown. The kind, characteristics, number, combination, arrangement, and the like of the other functional layers that the laminate may have may be appropriately set according to the purpose. For example, the polarizing plate with a retardation layer may further have a conductive layer or an isotropic substrate with a conductive layer. A polarizing plate with a retardation layer having a conductive layer or an isotropic substrate with a conductive layer is applied to, for example, a so-called internal touch panel type input display device in which a touch sensor is incorporated inside an image display panel. Further, as another example, the polarizing plate with a retardation layer may further have another retardation layer. The optical characteristics (for example, refractive index characteristics, in-plane retardation, nz coefficient, photoelastic coefficient), thickness, arrangement, and the like of the other retardation layer can be appropriately set according to the purpose. As a specific example, another retardation layer (typically, a layer imparting (elliptical) circularly polarized light function, a layer imparting ultra-high retardation) may be provided on the viewing side of the polarizer to improve the visibility in the case of viewing through a polarized sunglasses. By providing such a layer, even when a display screen is visually recognized through a polarizing lens such as a polarizing sunglasses, excellent visibility can be achieved, and the layer can be suitably used for an image display device that can be used outdoors.

The components constituting the laminate 100 may be laminated by any appropriate adhesive layer. Specific examples of the adhesive layer include an adhesive layer and an adhesive layer (also referred to as a pressure-sensitive adhesive layer). Although not shown, the protective layer 12 is bonded to the polarizer 11 by an adhesive layer (preferably, an active energy ray-curable adhesive) for example. Further, for example, the first phase difference layer 41 and the second phase difference layer 42 are laminated by an adhesive layer (preferably, an active energy ray-curable adhesive is used). The thickness of the adhesive layer is, for example, 0.05 μm or more, preferably 0.4 μm to 3.0 μm, and more preferably 0.6 μm to 2.2 μm.

The thickness of the laminated portion from the polarizing plate 10 to the first adhesive layer 31 (hereinafter, sometimes referred to as total thickness) is, for example, 160 μm or less, preferably 140 μm or less, and more preferably 120 μm or less. In addition, the total thickness includes the thickness of the adhesive layer.

The laminate 100 can be attached to an image display panel included in an image display device, for example, by the first adhesive layer 31. Although not shown, in practical use, a release liner is bonded to the surface of the first adhesive layer 31. The release liner may be temporarily affixed until the laminate is ready for use. By using a release liner, for example, the first adhesive layer 31 can be protected, and a roll of the laminate 100 can be formed.

The laminate 100 may be monolithic or elongated. In the present specification, "elongated" means an elongated shape having a length sufficiently long with respect to a width, and includes, for example, an elongated shape having a length of 10 times or more, preferably 20 times or more, with respect to a width. The elongated laminate can be wound into a roll.

The shape of the sheet-like laminate 100 in plan view is not particularly limited. The shape of the sheet-like laminate in a plan view is typically rectangular. The planar shape of the sheet-like layered body may be other than rectangular. Here, the shape other than the rectangle includes not only the case where the outer periphery is other than the rectangle, but also the case where the through hole is provided in the plane, for example. Specific examples of the case where the outer periphery is other than rectangular include a shape in which the outer periphery is partially cut off and a shape in which corners are chamfered. When a monolithic laminate having a through hole, a notch, a chamfer, or other shaped processing portion is processed, bending or local stress concentration tends to occur, and cracking tends to occur more easily. The profiled portion may be formed, for example, before integrating the laminate 100 with an image display panel body (for example, an organic EL panel body) described later, or may be formed in a state after integrating the laminate 100 with the image display panel body.

B. Polarizing plate

The polarizing plate 10 includes a polarizer 11 having a first main surface 11a and a second main surface 11b facing each other, and may further include a protective layer 12 disposed on the first main surface 11a side.

B-1 polarizer

The polarizer 11 is typically a resin film containing a dichroic substance (e.g., iodine). Examples of the resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially methylalized PVA films, and ethylene-vinyl acetate copolymer partially saponified films.

The thickness of the polarizer is, for example, 18 μm or less, preferably 15 μm or less, more preferably 12 μm or less, and still more preferably 8 μm or less. Such a thickness can greatly contribute to the thickness reduction of the laminate, for example. The thinner the polarizer, the higher the risk of cracking. Further, from the viewpoint of improving discoloration (e.g., end discoloration) of the polarizer, it may be advantageous to improve orientation (e.g., further increase boric acid crosslinking), but may be a trade-off relationship with cracks. The thickness of the polarizer is preferably 1 μm or more.

The polarizer preferably exhibits absorption dichroism at any wavelength from 380nm to 780 nm. The single body transmittance of the polarizer is, for example, 40.0% to 46.0%, preferably 41.0% to 45.0%, and more preferably 41.5% to 44.5%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and still more preferably 99.9% or more.

The polarizer may be fabricated in any suitable manner. Specifically, the polarizer may be made of a single-layer resin film, or may be made of a laminate including a base material.

The method for producing a polarizer from the single-layer resin film typically includes dyeing and stretching the resin film with a dichroic substance such as iodine or a dichroic dye. As the resin film, for example, a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film, a partially methylalized PVA film, or an ethylene-vinyl acetate copolymer partially saponified film is used. The method may further comprise an insolubilization treatment, a swelling treatment, a crosslinking treatment, and the like. Such a production method is a method known and used in the art, and detailed description thereof is omitted.

The polarizer obtained by using the laminate including the above-mentioned base material can be produced, for example, by using a laminate of a resin base material and a resin film or a resin layer (typically, a PVA-based resin layer). Specifically, the method can be carried out as follows: coating a PVA-based resin solution on a resin substrate, drying the resin substrate to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer; the laminate was stretched and dyed, and the PVA-based resin layer was used as a polarizer. In the present embodiment, it is preferable that a PVA-based resin layer including a halide and a PVA-based resin is formed on one side of a resin substrate. Stretching typically involves immersing the laminate in an aqueous boric acid solution to stretch. If necessary, stretching may further include air stretching (also referred to as atmospheric stretching) of the laminate at a high temperature (for example, 95 ℃ or higher) before stretching in the aqueous boric acid solution. In the present embodiment, the laminate is preferably subjected to a drying shrinkage process in which the laminate is heated while being transported in the longitudinal direction, and is shrunk by 2% or more in the width direction. Typically, the manufacturing method of the present embodiment includes sequentially subjecting the laminate to an air-assisted stretching treatment, a dyeing treatment, an in-water stretching treatment, and a drying shrinkage treatment. By introducing the auxiliary stretching, even when PVA is coated on the thermoplastic resin, crystallinity of PVA can be improved, and high optical characteristics can be achieved. Further, by simultaneously improving the orientation of PVA in advance, problems such as lowering and dissolution of the orientation of PVA can be prevented when immersed in water in the subsequent dyeing step and stretching step, and high optical characteristics can be achieved. In addition, in the case where the PVA-based resin layer is immersed in a liquid, disorder of orientation of PVA molecules and decrease of orientation property can be suppressed, and high optical characteristics can be achieved, as compared with the case where the PVA-based resin layer does not contain a halide. Further, the laminate is shrunk in the width direction by the drying shrinkage treatment, whereby high optical characteristics can be achieved. The polarizer may be obtained by peeling the resin substrate from the obtained laminate of the resin substrate and the polarizer, or by laminating a protective layer on the surface opposite to the peeling surface. Details of such a method for producing a polarizer are described in, for example, japanese patent application laid-open No. 2012-73580 and japanese patent No. 6470455. The entire disclosures of these publications are incorporated by reference into the present specification.

B-2. Protective layer

The protective layer 12 may be formed of, for example, any appropriate resin film that can be used as a protective layer of a polarizer. Specific examples of the resin that is the main component of the resin film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based resins, polyvinyl alcohol-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, polyether sulfone-based resins, polysulfone-based resins, cycloolefin-based resins such as polystyrene-based resins and polynorbornene-based resins, polyolefin-based resins, (meth) acrylic-based resins, and acetate-based resins.

The laminate 100 is typically disposed on the viewing side of the image display device, and the protective layer 12 is disposed on the viewing side. Therefore, if necessary, the protective layer 12 may be subjected to surface treatments such as Hard Coat (HC) treatment, antireflection treatment, anti-blocking treatment, and antiglare treatment.

The thickness of the protective layer is, for example, 5 μm to 80. Mu.m, preferably 10 μm to 50. Mu.m, and more preferably 15 μm to 35. Mu.m. In the case where the surface treatment is performed, the thickness of the protective layer includes the thickness of the surface treatment layer.

C. Resin layer

The resin layer 20 may have a barrier function. The resin layer 20 can suppress migration of iodine that may be contained in the polarizer, and can suppress discoloration of the polarizer (for example, discoloration at the outer peripheral end portion, discoloration in a region surrounding the through-holes in the case where the laminate has the through-holes). Further, the resin layer 20 can suppress the movement of iodine that may be contained in the polarizer, and can reduce the influence of the polarizer on other components. For example, when the laminate is mounted on an image display device (for example, an organic EL display device), corrosion of metal parts of the image display device can be suppressed.

The resin layer is typically a cured product or a cured product of a coating film of an organic solvent solution of a resin. With such a configuration, adhesion to the polarizer is excellent. Specifically, the polarizer may be disposed adjacent to the polarizer without an adhesive layer. In addition, the thickness of the resin layer can be made extremely thin. The thickness of the resin layer is, for example, 10 μm or less, preferably 5 μm or less, more preferably 1 μm or less, and still more preferably 0.7 μm or less. The thickness of the resin layer is preferably 0.05 μm or more, more preferably 0.08 μm or more, still more preferably 0.1 μm or more, and particularly preferably 0.2 μm or more.

In one embodiment, the glass transition temperature (Tg) of the resin constituting the resin layer is 85 ℃ or higher, and the weight average molecular weight (Mw) is 25000 or higher. The Tg of the resin constituting the resin layer is preferably 90 ℃ or higher, more preferably 100 ℃ or higher, still more preferably 110 ℃ or higher, and particularly preferably 120 ℃ or higher. Tg may be, for example, 200℃or lower. The Mw of the resin constituting the resin layer is preferably 30000 or more, more preferably 35000 or more, and even more preferably 40000 or more. By making Tg and Mw of the resin constituting the resin layer within such a range, excellent barrier function can be achieved despite the very thin thickness.

On the other hand, such a resin layer is hard and tends to easily crack. Specifically, if an impact (hereinafter, sometimes referred to as an external impact) is applied to the laminate 100 from the first main surface 11a side of the polarizer 11 when the protective layer is not disposed on the second main surface 11b side of the polarizer 11, cracks may occur in the resin layer 20. For example, external impacts may occur when the laminate is handled in a single piece, when the laminate is bonded to the image display panel main body, when the laminate is inspected after bonding, when other members are bonded to the laminate, when a plurality of laminates are stacked and stored and transported before bonding to the image display panel main body, and the like. Further, cracks in the resin layer 20 may affect adjacent members (for example, the polarizer 11). For example, it is considered that: in the case where the adhesive layer is uniformly present adjacent to the second main surface 11b of the polarizer 11, tensile stress that may be generated by external impact may be dispersed by the adhesive layer, but in the case where the broken resin layer 20 is present, tensile stress is locally applied to the polarizer 11 and cracks may be generated. Cracks in the polarizer 11 may be enlarged due to dimensional changes of the polarizer 11 that may occur due to heating or the like. In this case, for example, in the obtained image display device, display defects such as light leakage may occur. According to the embodiment of the present invention, by combining the first adhesive layer described later, occurrence of cracks can be suppressed while suppressing decoloration of the polarizer.

As the resin constituting the resin layer, any suitable resin that can form a cured product or a cured product (for example, a thermally cured product) of a coating film of an organic solvent solution can be used. As the resin constituting the resin layer, a thermoplastic resin or a thermosetting resin having Tg and Mw as described above is preferably used, and a thermoplastic resin is more preferably used. The resin may be used alone, or two or more kinds may be used in combination.

Examples of the thermoplastic resin include acrylic resins and epoxy resins. Acrylic resins and epoxy resins may also be used in combination.

The acrylic resin typically contains a repeating unit derived from a (meth) acrylate monomer having a linear or branched structure as a main component. The acrylic resin may contain a repeating unit derived from any suitable comonomer corresponding to the purpose. Examples of the comonomer (comonomer) include carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, aromatic ring-containing (meth) acrylates, and heterocyclic vinyl-containing monomers. By appropriately setting the kind, number, combination, copolymerization ratio, and the like of the monomer units, an acrylic resin having the above-specified Mw can be obtained. Specific examples of the acrylic resin include boron-containing acrylic resins and lactone-containing acrylic resins described in [0034] to [0056] of JP-A2021-117484.

As the epoxy resin, an epoxy resin having an aromatic ring is preferably used. By using an epoxy resin having an aromatic ring as the epoxy resin, adhesion between the protective layer and the polarizer can be improved. In addition, in the case where the adhesive layer is disposed adjacent to the protective layer, the anchoring force of the adhesive layer can be improved. Examples of the epoxy resin having an aromatic ring include bisphenol epoxy resins such as bisphenol a epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin; novolac epoxy resins such as phenol novolac epoxy resin, cresol novolac epoxy resin, hydroxybenzaldehyde phenol novolac epoxy resin, and the like; glycidyl ethers of tetrahydroxyphenyl methane, glycidyl ethers of tetrahydroxybenzophenone, epoxy polyvinylphenol and other multifunctional epoxy resins, naphthol-type epoxy resins, naphthalene-type epoxy resins, biphenyl-type epoxy resins and the like. Bisphenol A type epoxy resin, biphenyl type epoxy resin, bisphenol F type epoxy resin are preferably used. The epoxy resin may be used alone, or two or more kinds may be used in combination.

The resin layer can be typically formed by: the organic solvent solution of the above resin is applied to form a coating film, and the resulting coating film is cured or thermally cured. As the organic solvent, any suitable organic solvent that can dissolve or uniformly disperse the above resin can be used. Specific examples of the organic solvent include ethyl acetate, toluene, methyl Ethyl Ketone (MEK), methyl isobutyl ketone (MIBK), cyclopentanone, and cyclohexanone. The resin concentration of the solution is preferably 3 to 20 parts by weight relative to 100 parts by weight of the solvent. According to such a resin concentration, a uniform coating film can be formed.

The solution may be applied to a substrate prepared separately, but is preferably applied to a polarizing plate (polarizer). In the case of applying the solution to a substrate, a cured or hardened product (resin layer) of a coating film formed on the substrate is transferred onto a polarizing plate (polarizer). Transfer is typically performed through an adhesive layer, and therefore, the solution is applied to a polarizer (polarizer), whereby a resin layer is directly formed, and the adhesive layer can be omitted. As a method of applying the solution, any suitable method can be employed. Specific examples thereof include roll coating, spin coating, bar coating, dip coating, die coating, curtain coating, spray coating, and doctor blade coating (comma coating, etc.).

The heating temperature for curing or thermally curing the coating film is preferably 100 ℃ or less, more preferably 50 to 70 ℃. If the heating temperature is within such a range, adverse effects on the polarizer can be prevented. The heating time may be, for example, 1 minute to 10 minutes.

The resin layer (substantially an organic solvent solution of the above resin) may contain any appropriate additive according to the purpose. Specific examples of the additive include an ultraviolet absorber; a leveling agent; antioxidants such as hindered phenols, phosphorus, sulfur, etc.; stabilizers such as a light stabilizer, a weather stabilizer, and a heat stabilizer; reinforcing materials such as glass fibers and carbon fibers; a near infrared ray absorber; flame retardants such as tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide, and the like; antistatic agents such as anionic, cationic, and nonionic surfactants; colorants such as inorganic pigments, organic pigments, dyes, and the like; an organic filler or an inorganic filler; a resin modifier; an organic filler or an inorganic filler; a plasticizer; a lubricant; flame retardants, and the like. The kind, amount, combination, addition amount, and the like of the additives may be appropriately set according to the purpose.

D. Phase difference layer

The retardation layer 40 may have a laminated structure of two or more layers, or may be a single layer. The phase difference layer may be composed of any suitable material. Specifically, the retardation layer may be an alignment cured layer of a liquid crystal compound, a resin film (typically, a stretched film), or a combination thereof. The thickness of the retardation layer is, for example, 1 μm or more and 80 μm or less. In the case where the retardation layers have a laminated structure, the "thickness of the retardation layers" refers to the sum of the thicknesses of the retardation layers. Specifically, the "thickness of the retardation layer" does not include the thickness of the adhesive layer.

D-1. First phase difference layer

The first retardation layer 41 may have any suitable optical and/or mechanical properties depending on the purpose. The first phase difference layer typically has a slow axis. In one embodiment, the angle θ between the slow axis of the first retardation layer 41 and the absorption axis of the polarizer 11 is, for example, 40 ° to 50 °, preferably 42 ° to 48 °, and more preferably about 45 °. If the angle θ is within such a range, a polarizing plate with a retardation layer having very excellent circularly polarized light characteristics (as a result, having very excellent antireflection characteristics) can be obtained by using the first retardation layer as a λ/4 plate.

The first retardation layer preferably has refractive index characteristics exhibiting a relationship of nx > ny.gtoreq.nz. In one embodiment, the first phase difference layer may function as a λ/4 plate. In this case, the in-plane retardation Re (550) of the first retardation layer is, for example, 100nm to 190nm, preferably 110nm to 170nm, and more preferably 130nm to 160nm. Here, "ny=nz" includes not only the case where ny is completely equal to nz but also the case where ny is substantially equal to nz. Therefore, ny < nz may be present within a range that does not impair the effects of the present invention.

The Nz coefficient of the first retardation layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3. By satisfying such a relationship, when the obtained polarizing plate with a retardation layer is used for an image display device, a very excellent reflection color tone can be realized.

The first phase difference layer may exhibit an inverse wavelength dispersion characteristic in which the phase difference value becomes large according to the wavelength of the measurement light, a positive wavelength dispersion characteristic in which the phase difference value becomes small according to the wavelength of the measurement light, or a flat wavelength dispersion characteristic in which the phase difference value hardly changes according to the wavelength of the measurement light. In one embodiment, the first phase difference layer exhibits inverse wavelength dispersion characteristics. In this case, re (450)/Re (550) of the retardation layer is, for example, 0.8 or more and less than 1, preferably 0.8 or more and 0.95 or less. With such a configuration, extremely excellent antireflection characteristics can be achieved.

The absolute value of the photoelastic coefficient of the first phase difference layer is preferably 2×10 ^-11 m ² N or less, more preferably 2.0X10 ^-13 m ² /N～1.5×10 ^-11 m ² N, further preferably 1.0X10 ^-12 m ² /N～1.2×10 ^-11 m ² Resin of/N. If the absolute value of the photoelastic coefficient is within such a range, a change in phase difference is less likely to occur when shrinkage stress upon heating is generated. As a result, thermal unevenness of the obtained image display device can be well prevented.

The first retardation layer is typically composed of a stretched film of a resin film. The thickness of the first retardation layer is, for example, 70 μm or less, preferably 60 μm or less, more preferably 50 μm or less, and still more preferably 45 μm or less. If the thickness of the first retardation layer is within such a range, good bendability can be ensured, and the film can be suitably used for flexible applications, for example. On the other hand, the thickness of the first retardation layer is preferably 10 μm or more, more preferably 20 μm or more.

The first retardation layer may be formed of any suitable resin film capable of satisfying the above characteristics. Representative examples of such resins include polycarbonate-based resins, polyester-carbonate-based resins, polyester-based resins, polyvinyl acetal-based resins, polyarylate-based resins, cyclic olefin-based resins, cellulose-based resins, polyvinyl alcohol-based resins, polyamide-based resins, polyimide-based resins, polyether-based resins, polystyrene-based resins, and acrylic-based resins. These resins may be used alone or in combination (e.g., blending, copolymerization). In the case where the first retardation layer is formed of a resin film exhibiting inverse wavelength dispersion characteristics, a polycarbonate-based resin or a polyester carbonate-based resin (hereinafter, may be simply referred to as a polycarbonate-based resin) may be suitably used.

As the polycarbonate resin, any suitable polycarbonate resin can be used as long as the effects of the present invention can be obtained. For example, the polycarbonate resin contains a structural unit derived from a fluorene dihydroxy compound, a structural unit derived from an isosorbide dihydroxy compound, and a structural unit derived from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic dimethanol, di-, tri-, and polyethylene glycols, and alkylene glycols or spiro diols. Preferably, the polycarbonate resin contains a structural unit derived from a fluorene dihydroxy compound, a structural unit derived from an isosorbide dihydroxy compound, a structural unit derived from alicyclic dimethanol, and/or a structural unit derived from di-, tri-, or polyethylene glycol; it is further preferable that the composition contains a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from a di-, tri-or polyethylene glycol. The polycarbonate resin may contain a structural unit derived from another dihydroxy compound, if necessary. Details of the polycarbonate resin used for the first retardation layer and the method for forming the first retardation layer are described in, for example, japanese patent application laid-open No. 2014-10291, japanese patent application laid-open No. 2014-26262, japanese patent application laid-open No. 2015-212816, japanese patent application laid-open No. 2015-212817, and Japanese patent application laid-open No. 2015-212818, the disclosures of which are incorporated herein by reference.

D-2 second phase difference layer

The second phase difference layer 42 may be typically a so-called positive C plate whose refractive index characteristics show a relationship of nz > nx=ny. By using the positive C plate as the second phase difference layer, reflection in the oblique direction can be satisfactorily prevented, and a wide viewing angle of the antireflection function can be achieved.

The retardation Rth (550) of the second phase difference layer in the thickness direction is preferably-50 nm to-300 nm, more preferably-70 nm to-250 nm, further preferably-90 nm to-200 nm, particularly preferably-100 nm to-180 nm. Here, "nx=ny" includes not only the case where nx and ny are strictly equal but also the case where nx and ny are substantially equal. That is, the in-plane phase difference Re (550) of the second phase difference layer may be less than 10nm.

The second phase difference layer having refractive index characteristics of nz > nx=ny may be formed of any suitable material. The second phase difference layer is preferably formed of a film containing a liquid crystal material fixed in a vertical alignment. The liquid crystal material (liquid crystal compound) capable of vertical alignment may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the method for forming the liquid crystal compound and the retardation layer include those described in [0020] to [0028] of JP-A-2002-333642 and methods for forming the retardation layer. In this case, the thickness of the second phase difference layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and still more preferably 0.5 μm to 5 μm.

E-1. First adhesive layer

The storage modulus of the first adhesive layer 31 at-25 ℃ is 6.5X10 ⁶ Pa or more, preferably 7.0X10 ⁶ Pa or more, more preferably 7.5X10 ⁶ Pa or more. By providing the first adhesive layer having such a storage modulus, a laminate excellent in durability can be obtained. Specifically, by combining the first adhesive layer having such a storage modulus and the above-described resin layer, occurrence of cracks can be suppressed while suppressing discoloration of the polarizer. Specifically, it is possible to reduce the degree of deformation of the first adhesive layer 31 caused by external impact and suppress the occurrence of cracks. The storage modulus at-25℃of the first adhesive layer 31 is, for example, 5.0X10 ⁸ Pa or below.

The thickness of the first adhesive layer 31 is 25 μm or less, may be 22 μm or less, may be 19 μm or less, or may be 16 μm or less. Such a thickness can provide extremely excellent durability. Specifically, it is possible to reduce the degree of deformation of the first adhesive layer 31 caused by external impact and suppress the occurrence of cracks. On the other hand, the thickness of the first pressure-sensitive adhesive layer 31 is, for example, 10 μm or more, preferably 12 μm or more, and more preferably 14 μm or more from the viewpoints of ease of formation of the pressure-sensitive adhesive layer and adhesion to an adjacent layer.

The adhesive constituting the adhesive layer typically contains a (meth) acrylic polymer, a urethane polymer, a silicone polymer or a rubber polymer as a base polymer, and preferably contains a (meth) acrylic polymer. In the case of using a (meth) acrylic polymer as a base polymer, the adhesive layer is formed of, for example, an adhesive containing a (meth) acrylic polymer.

The (meth) acrylic polymer preferably has a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 1 to 30 carbon atoms in a side chain. The alkyl group may be linear or branched. Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, n-hexyl (meth) acrylate, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate. Further, alkyl (meth) acrylates having a long-chain alkyl group (for example, an alkyl group having 6 to 30 carbon atoms) in a side chain such as n-dodecyl (meth) acrylate and lauryl (meth) acrylate may be used. One or two or more kinds of alkyl (meth) acrylates may also be used.

The content of the alkyl (meth) acrylate in the total monomers constituting the (meth) acrylic polymer is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, and still more preferably 80% by weight or more. The upper limit of the content ratio may be, for example, 99.9% by weight or less.

The (meth) acrylic polymer may have a structural unit other than the structural unit derived from the alkyl (meth) acrylate. The structural unit is derived from a monomer (comonomer) capable of copolymerizing with an alkyl (meth) acrylate. The (meth) acrylic polymer may have one or more structural units derived from a comonomer.

Examples of the comonomer include carboxyl group-containing monomers. Specific examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. In one embodiment, the (meth) acrylic polymer may contain acrylic acid as a monomer component. The content of acrylic acid in all the monomers constituting the (meth) acrylic polymer is, for example, 0.01 to 5% by weight, preferably 0.05 to 2% by weight.

As other examples of the comonomer, hydroxyl group-containing monomers can be given. The hydroxyl group-containing monomer may be a hydroxyl group-containing (meth) acrylic monomer. Specific examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, and 12-hydroxylauryl (meth) acrylate, and methyl (4-hydroxymethylcyclohexyl) -acrylate. The content of the hydroxyl group-containing monomer in all the monomers constituting the (meth) acrylic polymer is, for example, 0.01 to 10% by weight, preferably 0.05 to 3% by weight.

As another example of the comonomer, an amide group-containing monomer may be mentioned. Specific examples of the amide group-containing monomer include acrylamide-based monomers such as (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-isopropyl acrylamide, N-methyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-hydroxymethyl-N-propane (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, mercaptomethyl (meth) acrylamide, and mercaptoethyl (meth) acrylamide; n-acryloylheterocyclic monomers such as N-methacryloyl morpholine, N- (meth) acryloylpiperidine and N- (meth) acryloylpyrrolidine; n-vinyllactam-containing monomers such as N-vinylpyrrolidone and N-vinyl-epsilon-caprolactam. The content of the amide group-containing monomer in all the monomers constituting the (meth) acrylic polymer is, for example, 0.01 to 10% by weight, preferably 0.05 to 3% by weight.

As another example of the comonomer, an amino group-containing monomer may be mentioned. Specific examples of the amino group-containing monomer include N, N-dimethylaminoethyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylate.

As another example of the comonomer, an aromatic ring-containing monomer may be mentioned. The aromatic ring-containing monomer may be an aromatic ring-containing (meth) acrylic monomer. Specific examples of the aromatic ring-containing monomer include phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide-modified nonylphenol (meth) acrylate, hydroxyethylated β -naphthol (meth) acrylate, and biphenyl (meth) acrylate.

As another example of the comonomer, there may be mentioned a (meth) acrylate represented by the following chemical formula (1). R of formula (1) ¹ Is an alkyl group. The alkyl group may be linear or branched. R is R ¹ A linear alkyl group is preferable. R is R ¹ Examples of (a) are methyl and ethyl. N in formula (1) is an integer of 1 to 15.

Specific examples of the (meth) acrylic acid ester represented by the formula (1) include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate and methoxytriethylene (meth) acrylate. When the (meth) acrylate of formula (1) is used, an adhesive layer having a small surface resistance value can be obtained with a small blending amount when an antistatic agent is blended into the adhesive layer.

As comonomers, polyfunctional monomers can also be used. As the polyfunctional monomer, there are: multifunctional acrylates such as hexanediol di (meth) acrylate (1, 6-hexanediol di (meth) acrylate), butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; divinylbenzene. The polyfunctional acrylate is preferably 1, 6-hexanediol diacrylate, dipentaerythritol hexa (meth) acrylate.

Examples of the other comonomer include epoxy group-containing monomers such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; sulfonic acid group-containing monomers such as sodium vinylsulfonate; a phosphate group-containing monomer; (meth) acrylic esters having alicyclic hydrocarbon groups such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyl toluene; olefins or dienes such as ethylene, propylene, butadiene, isoprene and isobutylene; vinyl ethers such as vinyl alkyl ether; vinyl chloride.

The (meth) acrylic polymer can be formed by polymerizing one or more of the above monomers by a known method. The monomers may also be polymerized with partial polymers (oligomers) of the monomers.

The weight average molecular weight (Mw) of the (meth) acrylic polymer is, for example, 100 to 280 ten thousand, preferably 120 ten thousand or more, more preferably 140 ten thousand or more, from the viewpoints of durability and heat resistance of the adhesive layer. The weight average molecular weight (Mw) was obtained as a value (in terms of polystyrene) based on measurement by GPC (gel permeation chromatography).

The content of the (meth) acrylic polymer in the binder is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, and still more preferably 80% by weight or more, based on the solid content. The upper limit of the content ratio may be, for example, 99.9% by weight or less, and preferably 99.8% by weight or less.

The binder may further contain additives. Specific examples of the additives include powders such as silane coupling agents, crosslinking agents, antioxidants, colorants, pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, granules, and foils. Further, a redox system to which a reducing agent is added may be used within a controllable range. The kind, amount, combination, content, etc. of the additives may be set to any appropriate value according to the purpose.

Examples of the crosslinking agent include organic crosslinking agents and polyfunctional metal chelates. Examples of the organic crosslinking agent are isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents and imine crosslinking agents. The crosslinking agent is preferably a peroxide-based crosslinking agent or an isocyanate-based crosslinking agent. The crosslinking agent may be used alone, or two or more thereof may be used in combination. For example, a peroxide-based crosslinking agent and an isocyanate-based crosslinking agent may be used in combination.

The amount of the crosslinking agent blended in the adhesive is, for example, 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the (meth) acrylic polymer.

As the silane coupling agent, a functional group-containing silane coupling agent is typically exemplified. Examples of the functional group include an epoxy group, a mercapto group, an amino group, an isocyanate group, an isocyanurate group, a vinyl group, a styryl group, an acetoacetyl group, a urea group, a thiourea group, a (meth) acryloyl group, a heterocyclic group, an acid anhydride group, and combinations thereof. The silane coupling agent may be used alone, or two or more kinds may be used in combination.

The amount of the silane coupling agent blended in the adhesive is, for example, 0.01 to 5 parts by weight, preferably 0.01 to 3 parts by weight, and more preferably 0.01 to 1 part by weight, based on 100 parts by weight of the (meth) acrylic polymer.

The first adhesive layer 31 preferably has an antistatic function (typically, conductivity). By providing the laminate 100 with a layer having an antistatic function, it is possible to prevent the image display panel from being defective due to electrification. For example, mislight emission of the organic EL panel (for example, a problem of the green panel due to mislight emission of the green pixel) and uneven alignment of liquid crystal in a liquid crystal cell mounted on the liquid crystal panel can be prevented. The first adhesive layer 31 can be adhered to the panel body of the image display panel, and thus the above-described drawbacks can be effectively prevented.

The surface resistivity of the first adhesive layer 31 is preferably 9×10 ¹¹ Omega/≡or less, more preferably 7×10 ¹¹ Omega/≡or less, more preferably 5×10 ¹¹ Ω/≡or less. The surface resistivity of the first adhesive layer 31 is, for example, 1×10 ¹⁰ Ω/≡or more, preferably 2×10 ¹⁰ Ω/≡or more.

The antistatic function can be imparted by making the first adhesive layer 31 contain an antistatic agent. As the antistatic agent, an ionic compound can be typically used.

Examples of the cations constituting the ionic compound include metal ions and onium ions. Examples of the metal ion include alkali metal ions and alkaline earth metal ions. Examples of the alkali metal ion include lithium ion, sodium ion, and potassium ion. Examples of the alkaline earth metal ion include magnesium ion and calcium ion.

Examples of the onium ion include ions in which at least one atom selected from the group consisting of a nitrogen atom, a phosphorus atom and a sulfur atom is positively charged (+). The onium ion may be an organic ion, and in this case, may be an ion of a cyclic organic compound or an ion of a chain organic compound. The cyclic organic compound may be aromatic or non-aromatic such as aliphatic. Specific examples of the onium ion include quaternary ammonium ions such as N-ethyl-N, N-dimethyl-N- (2-methoxyethyl) ammonium ion, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium ion, N-ethyl-N, N-dimethyl-N-propylammonium ion, N-methyl-N, N-trioctylammonium ion, N-trimethyl-N-propylammonium ion, tetrabutylammonium ion, tetramethylammonium ion, tetrahexylammonium ion, and N-methyl-N, N-tributylammonium ion; pyridinium ions such as N-alkylpyridinium substituted with an alkyl group having 4 to 16 carbon atoms; imidazolium ions such as 1, 3-alkylmethylimidazolium ions substituted with an alkyl group having 2 to 10 carbon atoms (for example, ethyl group) and 1, 2-dimethyl-3-alkylimidazolium ions substituted with an alkyl group having 2 to 10 carbon atoms; phosphonium ion, pyrrolidinium ion, pyridazinium ion, pyrimidinium ion, pyrazinium ion, pyrazolium ion, thiazolium ion, oxazolium ion, triazolium ion, and piperidinium ion.

Specific examples of anions constituting the ionic compound include fluoride, chloride, bromide, iodide, and perchlorate (ClO ₄ ^- ) Hydroxide (OH) ^- ) Carbonate (CO) ₃ ^2- ) Nitrate (NO) ₃ ^- ) Sulfonate (SO) ₄ ^- ) Methylbenzenesulfonate (CH) ₃ (C ₆ H ₄ )SO ₃ ^- ) Tosylate (CH) ₃ C ₆ H ₄ SO ₃ ^- ) Carboxybenzenesulfonate salt (COOH (C) ₆ H ₄ )SO ₃ ^- ) Trifluoromethane sulfonate (CF) ₃ SO ₂ ^- ) Benzoate (C) ₆ H ₅ COO ^- ) Acetate (CH) ₃ COO ^- ) Trifluoroacetate salt (CF) ₃ COO ^- ) Tetrafluoroborate (BF) ₄ ^- ) Tetrabenzyl borate (B (C) ₆ H ₅ ) ₄ ^- ) Hexafluorophosphate (PF) ₆ ^- ) Trifluoroethyl trifluorophosphate (P (C) ₂ F ₅ ) ₃ F ₃ ^- ) Bis-fluorosulfonyl imide (N (SO) ₂ F) ₂ ^- ) Bis-trifluoromethanesulfonyl imide (N (SO) ₂ CF ₃ ) ₂ ^- ) Bis-pentafluoroethane sulfonyl imide (N (SOC) ₂ F ₅ ) ₂ ^- ) Bis-pentafluoroethane carbonyl imide (N (COC) ₂ F ₅ ) ₂ ^- ) Bis-perfluorobutane sulfonyl imide (N (SO) ₂ C ₄ F ₉ ) ₂ ^- ) Bisperfluorobutane carbonyl imide (N (COC) ₄ F ₉ ) ₂ ^- ) Tris (trifluoromethylsulfonyl) methide (C (SO) ₂ CF ₃ ) ₃ ^- ) And tris (trifluoromethanecarbonyl) methide (C (SO) ₂ CF ₃ ) ₃ ^- )。

The ionic compound may also contain anions containing sulfur atoms. Specific examples of the sulfur atom-containing anion include bis-fluorosulfonyl imide (N (SO) ₂ F) ₂ ^- ) And bis (trifluoromethanesulfonyl) imide (N (SO) ₂ CF ₃ ) ₂ ^- )。

The ionic compound may also be an organic salt. The ionic compound may be a lithium salt, and the cations and anions may be lithium organic salts containing lithium ions and organic ions, respectively.

Specific examples of the ionic compound include 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (EMI-FSI), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), ethyl methyl pyrrolidinium bis (trifluoromethanesulfonyl) imide (EMPTFSI), and tributyl methyl ammonium bis (trifluoromethanesulfonyl) imide (TBMA-TFSI).

The ionic compound may not contain a phosphorus atom. Ionic compounds containing phosphorus atoms tend to easily corrode touch sensors (more specifically, conductive layers of touch sensors) of image display devices.

As the ionic compound used as the antistatic agent, an alkali metal salt is preferably used, and a lithium metal salt is more preferably used. The melting point of the ionic compound used as the antistatic agent is preferably 23℃or higher, more preferably 30℃or higher. By using such an ionic compound (for example, liTFSI), an adhesive layer that satisfactorily achieves the storage modulus and the surface resistivity can be obtained, and durability can be improved. In addition, the discoloration of the polarizer is not deteriorated.

The content of the antistatic agent is preferably 3 parts by weight or less, and may be 2 parts by weight or less, or may be 1 part by weight or less, based on 100 parts by weight of the base polymer of the first adhesive layer. According to the content ratio, plasticization of the first adhesive layer can be suppressed, and occurrence of cracks can be favorably suppressed. Further, according to such a content ratio, when the laminate is mounted on an image display device, corrosion of the touch sensor can be suppressed. For example, a protective film made of a metal such as Al or Ti, or a resin such as an acrylic or urethane may be formed on the touch sensor of the organic EL panel. However, the sulfur atoms contained in the antistatic agent may penetrate the protective film and corrode the touch sensor, as in the case of the phosphorus atoms described above. In the organic EL display device which is liable to cause corrosion, control of the antistatic agent of the first adhesive layer and the content ratio thereof may become important. On the other hand, the content of the antistatic agent is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, relative to 100 parts by weight of the base polymer of the first adhesive layer. As described above, the thickness of the first adhesive layer can be reduced from the viewpoint of durability (for example, crack suppression), but even in the case of a reduced thickness, the above-described surface resistance value can be satisfied by such a content ratio, and the green panel suppression effect can be obtained.

E-2. Second adhesive layer

The retardation layer 40 is bonded to the resin layer 20 via the second adhesive layer 32. As the adhesive constituting the second adhesive layer 32, any suitable adhesive may be used. For example, the same description as the adhesive constituting the first adhesive layer may be applied. The thickness of the second pressure-sensitive adhesive layer 32 is, for example, 1 μm to 50 μm, preferably 3 μm to 40 μm, more preferably 5 μm to 20 μm, still more preferably 5 μm to 10 μm.

F. Release liner

Examples of the release liner include flexible plastics. Examples of the plastic include a polyethylene terephthalate film, a polyethylene film, a polypropylene film, and a polyester film. The thickness of the release liner is, for example, 3 μm or more and, further, 200 μm or less. The surface of the release liner is coated with a release agent. Specific examples of the release agent include silicone release agents, fluorine release agents, and long-chain alkyl acrylate release agents.

G. Image display device

The laminate can be applied to an image display device. Accordingly, the image display device according to the embodiment of the present invention includes the above-described laminate. As typical examples of the image display device, a liquid crystal display device and an Electroluminescence (EL) display device (for example, an organic EL display device and an inorganic EL display device) are given.

Fig. 2 is a cross-sectional view schematically showing a schematic configuration of an image display panel included in the image display device according to an embodiment of the present invention, taking an organic EL display device as an example. The image display panel (organic EL panel) 200 includes an image display panel body (organic EL panel body) 70 and a laminate 100 disposed on the viewing side thereof. The laminate 100 is disposed closer to the organic EL panel body 70 than the polarizer 11 is, and the laminate 100 is bonded to the organic EL panel body 70 through the first adhesive layer 31. When the laminate is attached to the image display panel body, when a plurality of laminates are stacked and stored or transported before the attachment to the image display panel body, or the like, the above-described cracks tend to be easily generated if an external impact is applied to the laminate. According to the laminate of the embodiment of the present invention, such an operation crack can be favorably suppressed.

The organic EL panel body 70 has a substrate 71 and an upper structural layer 72, and the upper structural layer 72 includes a circuit layer including a Thin Film Transistor (TFT) or the like, an Organic Light Emitting Diode (OLED), a sealing film sealing the OLED, and the like. The upper structural layer 72 may include metal components (e.g., electrodes, sensors, wiring, metal layers). For example, in the case of using a flexible substrate (for example, a resin substrate) as the substrate 71, the obtained organic EL display device can be bent, buckled, folded, wound, or the like. The laminate according to the embodiment of the present invention is thin and can be suitably used for such an image display device. Further, the laminate having the first adhesive layer which may have an antistatic function can appropriately prevent false light emission caused by electrification in the organic EL panel.

Examples

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In addition, various measurement methods are described below. Unless otherwise specified, "parts" and "%" in examples and comparative examples are based on weight.

1. Thickness of (L)

The thickness of 1 μm or less was measured by a scanning electron microscope (product name "JSM-7100F" manufactured by Japanese electronics Co., ltd.). The thickness exceeding 1 μm was measured using a digital micrometer (An Li (manufactured by Anritsu) under the product name "KC-351C").

2. Glass transition temperature (Tg) of resin forming resin layer

About 5mg of a sample (polymer) was taken, DSC measurement was performed under the following conditions, and the intermediate point glass transition temperature was calculated from the measurement results obtained.

Measurement device: TAInstruments, product name: q-2000

Temperature program: varying in a manner of 0 ℃ to 150 ℃ to 0 ℃ to 150 DEG C

Atmosphere gas: n (N) ₂ (50 mL/min)

Measurement speed: 10 ℃/min

3. Weight average molecular weight (Mw)

The measurement was performed by Gel Permeation Chromatography (GPC), and the measurement was performed as a value in terms of standard polystyrene. Considering the base polymer concentration of the object to be measured, a 0.2 wt% THF solution was prepared, left at room temperature for 220 hours, and then the solution was filtered with a 0.45 μm membrane filter, and the filtrate was supplied to the measurement. The measurement conditions are as follows.

Analysis device: manufactured by Waters, alliance

Column: manufactured by Tosoh corporation, G7000H _XL +GMH _XL +GMH _XL

Column temperature: 40 DEG C

Flow rate: 0.8ml/min

Injection amount: 100 μl of

Eluent: tetrahydrofuran (THF)

Detector: differential Refractometer (RI)

Standard sample: polystyrene (PS)

4. In-plane phase difference Re (lambda)

The in-plane retardation at each wavelength at 23℃was measured using a Miller matrix polarimeter (manufactured by Axometrics, product name "Axoscan").

5. Melting point of antistatic agent

The melting point is determined by capillary methods. The finely pulverized measurement object was placed in a glass capillary having an inner diameter of about 1mm and a wall thickness of 0.1 to 0.2mm and a filling level of 2 to 3mm, and the glass capillary was inserted into a heating table equipped with a high-precision thermometer and heated, and the melting temperature of the measurement object was checked.

6. Storage modulus of adhesive layer

A laminate having a thickness of about 1.5mm was formed by laminating a plurality of adhesive layers, and was used as a sample for measurement. As a measurement device, "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific corporation was used, and dynamic viscoelasticity was measured under the following conditions, and storage modulus at 23 ℃ or 110 ℃ was read from the measurement result.

(measurement conditions)

Deformation mode: torsion

Frequency: 1Hz

Crimp load: 100g of

Temperature increase rate: 5 ℃/min

Temperature range: -50-150 DEG C

Shape: parallel plate, 8.0mm phi

7. Surface resistivity of adhesive layer

Will be formed at strippingThe pressure-sensitive adhesive layer on the liner was left in this state for 1 minute in a room (temperature: 25.+ -. 5 ℃ C., relative humidity: 50.+ -. 10%) and then the surface resistivity of the pressure-sensitive adhesive layer was measured by using a high-resistivity meter (manufactured by Mitsubishi chemical analysis, inc. 'Hiresta MCP-HT 450'). The upper limit of measurement of the surface resistivity was 1×10 ¹⁴ Ω/□。

Example 1

(production of polarizer)

As the thermoplastic resin substrate, an amorphous isophthalic acid copolymerized polyethylene terephthalate film (thickness 100 μm) having a long shape and a Tg of about 75 ℃ was used, and one side of the resin substrate was subjected to corona treatment.

In the case where polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (trade name "Gohsenx Z410" manufactured by Mitsubishi chemical Co., ltd.) were used in the following manner, the following amounts were 9:1 to 100 parts by weight of the PVA-based resin mixed in the above step, 13 parts by weight of potassium iodide was added, and the resultant was dissolved in water to prepare a PVA aqueous solution (coating liquid).

The PVA aqueous solution was applied to the corona treated surface of the resin substrate and dried at 60 ℃ to form a PVA-based resin layer having a thickness of 13 μm, thereby producing a laminate.

The resulting laminate was uniaxially stretched to 2.4 times in the machine direction (lengthwise direction) in an oven at 130 c (air-assisted stretching treatment).

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

Next, the resulting polarizer was immersed in a dyeing bath (aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with respect to 100 parts by weight of water) at a liquid temperature of 30 ℃ for 60 seconds while adjusting the concentration so that the monomer transmittance (Ts) of the resulting polarizer became a desired value (dyeing treatment).

Then, the resultant mixture was immersed in a crosslinking bath (aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40℃for 30 seconds (crosslinking treatment).

Then, the laminate was uniaxially stretched (in-water stretching treatment) between rolls having different peripheral speeds while being immersed in an aqueous boric acid solution (boric acid concentration 4 wt% and potassium iodide concentration 5 wt%) at a liquid temperature of 70 ℃ so that the total stretching ratio in the machine direction (longitudinal direction) became 5.5 times.

Then, the laminate was immersed in a washing bath (aqueous solution obtained by mixing 100 parts by weight of water with 4 parts by weight of potassium iodide) at a liquid temperature of 20 ℃ (washing treatment).

Then, the material was dried in an oven maintained at about 90 ℃ while being brought into contact with a SUS-made heating roller maintained at a surface temperature of about 75 ℃ (drying shrinkage treatment).

Thus, a polarizer having a thickness of 5 μm was formed on the resin substrate.

(production of polarizing plate)

The surface of the polarizer obtained (the surface opposite to the resin substrate) was bonded with an HC-TAC film as a protective layer by an ultraviolet curable adhesive to obtain a polarizing plate. Specifically, the cured adhesive was applied so that the thickness of the cured adhesive became 1.0 μm, and the cured adhesive was bonded by using a roll press. Then, UV light is irradiated from the protective layer side to cure the adhesive. The HC-TAC film was formed by forming a Hard Coat (HC) layer (thickness 7 μm) on a triacetyl cellulose (TAC) film (thickness 25 μm), and was bonded so that the TAC film became the polarizer side.

(formation of resin layer)

In 200 parts of toluene, 97.0 parts of methyl methacrylate (MMA, fuji film and Wako pure chemical industries, ltd., trade name "methyl methacrylate monomer"), 3.0 parts of a comonomer represented by the following formula (1 e), and 0.2 parts of a polymerization initiator (Fuji film and Wako pure chemical industries, ltd., trade name "2,2' -azobis (isobutyronitrile)") were dissolved. Then, polymerization was carried out under a nitrogen atmosphere for 5.5 hours while heating to 70℃to obtain a boron-containing acrylic resin solution (solid content: 33%). The Tg of the resulting boron-containing acrylic polymer (resin) was 110℃and the Mw was 80000.

The obtained boron-containing acrylic resin 20 parts was dissolved in methyl ethyl ketone 80 parts to obtain a resin solution (20%). The resin base material was peeled off from the polarizer, and after the resin solution was applied to the peeled surface by using a wire bar, the applied film was dried at 60℃for 5 minutes to form a resin layer (thickness: 400 nm) composed of a cured product of the applied film as an organic solvent solution of the resin. Thus, a laminate 1 having a structure of a protective layer, an adhesive layer, a polarizer, and a resin layer was obtained.

(preparation of first phase-difference layer)

In a batch polymerization apparatus comprising two vertical reactors each having stirring blades and a reflux cooler controlled at 100 ℃, bis [9- (2-phenoxycarbonylethyl) fluoren-9-yl ] was introduced]29.60 parts by weight (0.046 mol) of methane, 29.21 parts by weight (0.200 mol) of Isosorbide (ISB), 42.28 parts by weight (0.139 mol) of Spiroglycol (SPG), 63.77 parts by weight (0.298 mol) of diphenyl carbonate (DPC) and 1.19X10 of calcium acetate monohydrate as a catalyst ^-2 Parts by weight (6.78X10) ^-5 mol). After the reduced pressure nitrogen gas was replaced in the reactor, the reactor was heated by a heat medium, and stirring was started at the time when the internal temperature became 100 ℃. After 40 minutes from the start of the temperature rise, the internal temperature was brought to 220℃and the pressure was reduced while the temperature was kept at that temperature, and 13.3kPa was reached within 90 minutes after the temperature was reached 220 ℃. The phenol vapor produced as a by-product of the polymerization reaction was introduced into a reflux condenser at 100℃and a certain amount of monomer components contained in the phenol vapor was returned to the reactor, and the uncondensed phenol vapor was introduced into a condenser at 45℃and recovered. After introducing nitrogen gas into the first reactor and temporarily returning to the atmospheric pressure, the oligomerization reaction liquid in the first reactor was transferred to the second reactor. Then, the temperature rise and the pressure reduction in the second reactor were started, and the internal temperature was 240℃and the pressure was 0.2kPa within 50 minutes. Then, polymerization was performed until a predetermined stirring power was reached. After nitrogen was introduced into the reactor at the time of reaching the predetermined power and the pressure was recovered, 0.7 parts by mass of PMMA was melt-kneaded with respect to 100 parts by weight of the produced polyestercarbonate resin, and then the mixture was extruded into water to obtain strands Cutting to obtain pellets.

After the obtained polyester-carbonate resin (pellet) was dried under vacuum at 80℃for 5 hours, a film-forming apparatus comprising a single screw extruder (manufactured by Toshiba machinery Co., ltd., cylinder set temperature: 250 ℃), a T die (width 200mm, set temperature: 250 ℃), a cooling roll (set temperature: 120 to 130 ℃) and a winder was used to prepare a resin film in the form of a long film having a thickness of 105. Mu.m. The obtained long resin film was stretched 2.8 times in the width direction at 138℃while adjusting the phase difference to a predetermined value, to obtain a stretched film having a thickness of 38. Mu.m. The Re (550) of the obtained stretched film was 144nm, and Re (450)/Re (550) was 0.86.

(production of second phase-difference layer)

A liquid crystal coating liquid was prepared by dissolving 20 parts by weight of a side chain type liquid crystal polymer represented by the following chemical formula (3) (in which numerals 65 and 35 represent mol% of monomer units, and which is represented by a block polymer: weight average molecular weight 5000), 80 parts by weight of a polymerizable liquid crystal (manufactured by BASF corporation: paliocolor LC 242) exhibiting a nematic liquid crystal phase, and 5 parts by weight of a photopolymerization initiator (manufactured by steam type chemical corporation: irgacure 907) in 200 parts by weight of cyclopentanone for convenience. Then, after the coating liquid was coated on the PET substrate subjected to the vertical alignment treatment using a bar coater, the liquid crystal was aligned by drying and heating at 80 ℃ for 4 minutes. The liquid crystal layer was irradiated with ultraviolet light to cure the liquid crystal layer, whereby a liquid crystal alignment cured layer (thickness 3 μm) exhibiting refractive index characteristics of nz > nx=ny was formed on the substrate.

The second retardation layer (liquid crystal alignment cured layer) was bonded to the first retardation layer (stretched film) with an ultraviolet curable adhesive (thickness after curing: 1 μm), to obtain a laminate 2 having a configuration of the first retardation layer/adhesive layer/second retardation layer.

(production of the second adhesive layer)

Into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet tube and a cooler, a monomer mixture containing 91.5 parts of butyl acrylate, 3 parts of acrylic acid, 0.5 part of 4-hydroxybutyl acrylate and 5 parts of acryloylmorpholine was charged. Further, 0.1 part of 2,2' -azobisisobutyronitrile as a polymerization initiator was added together with 100 parts of ethyl acetate to 100 parts of the monomer mixture, nitrogen was introduced while being slowly stirred, and the inside of the flask was replaced with nitrogen, and then the liquid temperature in the flask was kept at around 55℃to carry out a polymerization reaction for 8 hours. Next, ethyl acetate was added to the obtained reaction solution and the concentration of the solid content was adjusted to 12% by weight, thereby preparing a solution of an acrylic polymer having a weight average molecular weight (Mw) of 250 ten thousand.

An acrylic pressure-sensitive adhesive was prepared by mixing 100 parts of the solid content of the obtained acrylic polymer solution with 0.3 part of benzoyl peroxide (trade name: nyper BMT, manufactured by Japanese fat and oil Co., ltd.), 0.2 part of trimethylolpropane/toluene diisocyanate adduct (trade name: coronate L, manufactured by Tosoh Co., ltd.), and 0.2 part of silane coupling agent (trade name: KBM403, manufactured by Xinyue chemical Co., ltd.).

The obtained acrylic pressure-sensitive adhesive was applied to a release surface of a PET film (MRF 38, manufactured by Mitsubishi chemical polyester film Co., ltd.) having a release liner having a thickness of 38 μm, which was silicone-treated on the release surface, and dried to form a second pressure-sensitive adhesive layer having a thickness of 5. Mu.m.

(preparation of first adhesive layer)

A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet tube and a cooler was charged with a monomer mixture containing 89.8 parts of butyl acrylate, 0.2 part of acrylic acid, 0.5 part of 4-hydroxybutyl acrylate, 1.5 parts of N-vinylpyrrolidone and 8 parts of methyl methacrylate. Further, 0.1 part of 2,2' -azobisisobutyronitrile as a polymerization initiator was added together with 100 parts of ethyl acetate to 100 parts of the monomer mixture, nitrogen was introduced while being slowly stirred, and the inside of the flask was replaced with nitrogen, and then the liquid temperature in the flask was kept at around 55℃to carry out a polymerization reaction for 8 hours. Next, ethyl acetate was added to the obtained reaction solution and the concentration of the solid content was adjusted to 12% by weight, to prepare a solution of an acrylic polymer having a weight average molecular weight (Mw) of 160 ten thousand.

An acrylic adhesive was prepared by blending 100 parts of the solid content of the obtained acrylic polymer solution with 0.3 part of benzoyl peroxide (trade name: nyper BMT, manufactured by Japanese fat and oil Co., ltd.), 0.2 part of trimethylolpropane hexamethylene diisocyanate (trade name: takenate D-160N, manufactured by Mitsui chemical Co., ltd.), 0.2 part of silane coupling agent (trade name: KBM403, manufactured by Xinyue chemical Co., ltd.), and 0.3 part of LiTFSi having a melting point of 232℃as an antistatic agent.

The obtained acrylic adhesive was applied to a release surface of a PET film (MRF 38, manufactured by Mitsubishi chemical polyester film Co., ltd.) having a release liner having a thickness of 38 μm, which was a release liner having a silicone treatment on the release surface, and dried to give a film having a storage modulus of 7.5X10 at-25℃having a thickness of 15 μm ⁶ Pa, surface resistivity of 2X 10 ¹¹ And a first adhesive layer of Ω/≡..

The second adhesive layer is transferred from a release liner onto the resin layer of the laminate 1, and the laminate 2 is bonded through the second adhesive layer. Here, the lamination is performed such that the first retardation layer of the laminate 2 is located on the resin layer side, and further such that the slow axis of the first retardation layer is at an angle of 45 ° with respect to the absorption axis of the polarizer of the laminate 1.

Next, the first adhesive layer was transferred from a release liner onto the second retardation layer of the laminate 2, to obtain a polarizing plate with a retardation layer as follows: has a constitution of a protective layer/an adhesive layer/a polarizer/a resin layer/a second adhesive layer/a first retardation layer/an adhesive layer/a second retardation layer/a first adhesive layer, and a thickness of a laminated portion from the protective layer to the first adhesive layer was 100 μm.

Example 2

A polarizing plate with a retardation layer having a thickness of 105 μm from the protective layer to the laminated portion of the first adhesive layer was obtained in the same manner as in example 1, except that the thickness of the first adhesive layer was changed to 20 μm. In addition, the surface resistivity of the first adhesive layer was 2×10 ¹¹ Ω/□。

Example 3

A polarizing plate with a retardation layer having a thickness of 95 μm from the protective layer to the laminated portion of the first adhesive layer was obtained in the same manner as in example 1, except that the thickness of the first adhesive layer was changed to 10 μm. In addition, the surface resistivity of the first adhesive layer was 5×10 ¹¹ Ω/□。

Example 4

A polarizing plate with a retardation layer having a thickness of 100 μm from the protective layer to the laminated portion of the first adhesive layer was obtained in the same manner as in example 1, except that the adhesive layer produced in the following manner was used as the first adhesive layer.

(preparation of first adhesive layer)

A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet tube and a cooler was charged with a monomer mixture containing 89.82 parts of butyl acrylate, 0.2 part of acrylic acid, 0.48 part of 4-hydroxybutyl acrylate, 1.5 parts of N-vinylpyrrolidone and 8 parts of methyl methacrylate. Further, 0.1 part of 2,2' -azobisisobutyronitrile as a polymerization initiator was added together with 100 parts of ethyl acetate to 100 parts of the monomer mixture, nitrogen was introduced while being slowly stirred, and the inside of the flask was replaced with nitrogen, and then the liquid temperature in the flask was kept at around 55℃to carry out a polymerization reaction for 8 hours. Next, ethyl acetate was added to the obtained reaction solution and the solid content concentration was adjusted to 12% by weight, to prepare a solution of an acrylic polymer having a weight average molecular weight (Mw) of 110 ten thousand.

An acrylic adhesive was prepared by blending 100 parts of the solid content of the obtained acrylic polymer solution with 0.25 part of benzoyl peroxide (trade name: nyper BMT, manufactured by Japanese fat and oil Co., ltd.), 0.25 part of trimethylolpropane hexamethylene diisocyanate (trade name: takenate D-160N, manufactured by Mitsui chemical Co., ltd.), 0.2 part of organosilane (trade name: A100, manufactured by Sanin chemical Co., ltd.), 0.2 part of a thiol-group-containing silane coupling agent (trade name: X41-1810, manufactured by Xinyue chemical Co., ltd.), 0.1 part of a reprocessing improver (trade name: silyl SAT10, manufactured by Belgium Co., ltd.), 0.3 part of an antioxidant (trade name: irganox 1010, manufactured by BASF Co., ltd.), and 2.5 parts of LiTFSi having a melting point of 232 ℃.

The obtained acrylic adhesive was applied to a release surface of a PET film (MRF 38, manufactured by Mitsubishi chemical polyester film Co., ltd.) having a release liner having a thickness of 38 μm, which was silicone-treated on the release surface, and dried to give a film having a storage modulus of 15X 10 at-25℃and a thickness of 15 μm ⁶ Pa, surface resistivity of 2X 10 ¹⁰ And a first adhesive layer of Ω/≡..

Comparative example 1

A polarizing plate with a retardation layer having a thickness of 115 μm was obtained from the protective layer to the laminated portion of the first adhesive layer in the same manner as in example 1, except that the thickness of the first adhesive layer was changed to 30 μm. In addition, the surface resistivity of the first adhesive layer was 1×10 ¹¹ Ω/□。

Comparative example 2

In the production of the first adhesive layer, a polarizing plate with a retardation layer having a thickness of 105 μm from the protective layer to the laminated portion of the first adhesive layer was obtained in the same manner as in example 2, except that EMI-FSi having a melting point of-12.9 ℃ was used instead of LiTFSi as the antistatic agent. In addition, the storage modulus at-25℃of the first adhesive layer was 6.0X10 ⁶ Pa, surface resistivity of 2X 10 ¹¹ Ω/□。

Comparative example 3

In the production of the first adhesive layer, a polarizing plate with a retardation layer having a thickness of 105 μm from the protective layer to the laminated portion of the first adhesive layer was obtained in the same manner as in example 2, except that EMI-FSi having a melting point of-12.9 ℃ was used instead of LiTFSi as the antistatic agent and the compounding amount of the antistatic agent was set to 1 part. In addition, the storage modulus at-25℃of the first adhesive layer was 5.5X10 ⁶ Pa, surface resistivity of 2X 10 ¹⁰ Ω/□。

Comparative example 4

In the production of the first adhesive layer, instead of LiTFSi as an antistatic agent, TBMA-TFSi having a melting point of 27℃was usedExcept that the compounding amount of the antistatic agent was set to 1 part, a polarizing plate with a retardation layer having a thickness of 105 μm from the protective layer to the laminated portion of the first adhesive layer was obtained in the same manner as in example 2. In addition, the storage modulus at-25℃of the first adhesive layer was 5.5X10 ⁶ Pa, surface resistivity of 2X 10 ¹⁰ Ω/□。

Comparative example 5

A polarizing plate with a retardation layer was obtained in the same manner as in example 2, except that a resin layer was not formed on the polarizer, as follows: has a constitution of a protective layer/an adhesive layer/a polarizer/a second adhesive layer/a first retardation layer/an adhesive layer/a second retardation layer/a first adhesive layer, and a thickness of a laminated portion from the protective layer to the first adhesive layer was 105 μm.

Reference example 1

A polarizing plate with a retardation layer was obtained in the same manner as in example 1, except that a film having a thickness of 20 μmtac was bonded to the polarizer with an ultraviolet curable adhesive instead of the resin layer being formed, and the polarizing plate was provided with the following retardation layer: has a constitution of a protective layer/an adhesive layer/a polarizer/an adhesive layer/a protective layer/a second adhesive layer/a first retardation layer/an adhesive layer/a second retardation layer/a first adhesive layer, and a thickness of a laminated portion from the protective layer to the first adhesive layer was 147 μm.

The following evaluations were performed for examples and comparative examples. The evaluation results are summarized in table 1 together with various values.

< evaluation >

1. End decoloring

Test pieces having a width of 40cm×a length of 40cm (the absorption axis direction of the polarizer was the width direction) were cut out from the obtained polarizing plate with the retardation layer. The test piece was attached to a glass plate, and after standing in an oven at 65℃and a relative humidity of 95% for 336 hours in this state, it was confirmed whether discoloration occurred from the end of the polarizer. The confirmation was performed by observing the end edge of the polarizer in the absorption axis direction by a microscope under cross transmission (a condition of transmitting incident light polarized in the absorption axis direction of the polarizer). Specifically, the position of the same color tone as the center of the test piece was visually determined from the end of the test piece, and the length measurement was performed on the distance (end decoloring width) from the end of the test piece to the position of the same color tone as the center of the test piece by using the length measurement program of the microscope.

2. Guitar pick test (durability)

From the obtained polarizing plate with a retardation layer, test pieces having a width of 50cm×a length of 150cm (the absorption axis direction of the polarizer was the width direction) were cut. As shown in fig. 3, the test piece S was bonded to the glass plate G, and the guitar pick P (model "HP2H (HARD)", manufactured by the company HISTORY) was pressed against the center of the test piece S in the width direction, and was slid at a speed of 7.5 m/min by reciprocating the guitar pick P50 times over a distance of 10cm in the longitudinal direction of the test piece S while applying a load of 200G to the guitar pick P. Then, after the test piece S was left to stand in an environment at a temperature of 80 ℃ for 1 hour, the number of cracks of the light leakage of the sample S was counted by microscopic observation.

3. Stripping off

From the obtained polarizing plate with a retardation layer, a test piece having a width of 70cm×a length of 150cm was cut out so that the longitudinal direction thereof became the absorption axis direction of the polarizer. The test piece was attached to an alkali-free glass plate, and the test piece was allowed to stand in this state for 500 hours at a temperature of 60℃and an atmosphere of 95% relative humidity, thereby being subjected to a wet heat test. After the wet heat test, the test piece was visually observed or by a magnifying glass to confirm whether or not the test piece was peeled off. The evaluation criteria are as follows.

(evaluation criterion)

Good: no peeling was confirmed

Poor: confirm the peeling

TABLE 1

As shown in table 1, the polarizing plate with a retardation layer of examples has a small decoloring width and is excellent in durability. As shown in the SEM observation of the cross section of fig. 4, the crack generated in the guitar pick test propagates to the polarizer with the resin layer as the starting point. In example 3, peeling was confirmed at the interface between the alkali-free glass plate of the adherend and the first adhesive layer by the wet heat test.

Industrial applicability

The laminate according to the embodiment of the present invention can be used for an image display device, for example. As the image display device, a liquid crystal display device, an organic EL display device, and an inorganic EL display device are typically exemplified.

Description of the reference numerals

10. Polarizing plate

11. Polarizer

12. Protective layer

20. Resin layer

31. First adhesive layer

32. Second adhesive layer

40. Phase difference layer

41. First phase difference layer

42. Second phase difference layer

100. A laminate.

Claims

1. A laminate, comprising: a polarizer including a polarizer; a first adhesive layer; and a resin layer disposed between the polarizer and the first adhesive layer,

the polarizer is disposed adjacent to the resin layer,

The resin layer contains a resin having a glass transition temperature of 85 ℃ or higher and a weight average molecular weight Mw of 25000 or higher,

the first adhesive layer has a thickness of 25 μm or less and a storage modulus at-25 ℃ of 6.5X10 ⁶ Pa or more.

2. The laminate according to claim 1, wherein the first adhesive layer contains an antistatic agent which is an ionic compound having a melting point of 23 ℃ or higher.

3. The laminate according to claim 2, wherein the anion constituting the ionic compound is bis (trifluoromethanesulfonyl) imide anion.

4. The laminate according to claim 2, wherein the ionic compound is an alkali metal salt.

5. The laminate according to claim 4, wherein the alkali metal salt is a lithium salt.

6. The laminate according to claim 2, wherein the antistatic agent is contained in an amount of 3 parts by weight or less relative to 100 parts by weight of the base polymer of the first adhesive layer.

7. The laminate according to claim 2, wherein the first adhesive layer has a surface resistivity of 9 x 10 ¹¹ Ω/≡or less.

8. The laminate according to claim 1, which comprises a retardation layer disposed between the resin layer and the first adhesive layer and comprising at least a first retardation layer,

The thickness of the laminated portion from the polarizing plate to the phase difference layer is 120 μm or less.

9. The laminate according to claim 8, wherein the first phase difference layer is a stretched film of a resin film.

10. The laminate according to claim 8, wherein the thickness of the first retardation layer is 10 μm or more.

11. The laminate according to claim 8, wherein Re (550) of the first retardation layer is 100nm to 190nm, and Re (450)/Re (550) is 0.8 or more and less than 1.

12. An image display device having the laminate of any one of claims 1 to 11.

13. An organic EL display device having the laminate of any one of claims 1 to 11.

14. The organic EL display device according to claim 13, wherein the laminate has a profile-processed portion.

15. A method of manufacturing an image display device, comprising:

preparing the laminate of any one of claims 1 to 11; and

the laminate is bonded to the image display panel body.