TW202039237A - Multilayer body and display device comprising same - Google Patents

Abstract

The purpose of the present invention is to provide a multilayer body which has improved durability by suppressing the generation of air bubbles in an adhesive layer. The present invention provides a multilayer body which sequentially comprises a front plate, a first adhesive layer that is formed using a first adhesive composition, a polarizer layer, a second adhesive layer that is formed using a second adhesive composition, and a back plate in this order, and which is configured such that if a first adhesive basis layer is formed using the first adhesive composition and a second adhesive basis layer is formed using the second adhesive composition so that the thickness of the first adhesive basis layer is equal to the thickness of the second adhesive basis layer, the first adhesive basis layer and the second adhesive basis layer satisfy the relational expression [Delta]R1 > [Delta]R2.

Description

Laminated body and display device containing the same

The present invention relates to a laminate and a display device including the laminate.

Korean Patent No. 10-2016-0053788 (Patent Document 1) and Korean Patent No. 10-2017-0093610 (Patent Document 2) respectively describe a laminate for display devices having a plurality of adhesive layers. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Korean Patent No. 10-2016-0053788 Specification [Patent Document 2] Korean Patent No. 10-2017-0093610 Specification

[The problem to be solved by the invention] The adhesive layer used in such a laminate is generally excellent in stress relaxation performance for relaxing external stress. However, when the laminate is bent at normal temperature, air bubbles are often generated in the adhesive layer. Therefore, it is required to improve the durability of the adhesive layer.

In view of the above-mentioned actual situation, an object of the present invention is to provide a laminate whose durability is improved by suppressing the generation of bubbles in an adhesive layer, and a display device including the laminate. [Means to solve the problem]

The present invention provides the following laminate and a display device including the same. [1] A laminated body comprising in order: a front surface plate; a first adhesive layer formed using a first adhesive composition; a polarizer layer; a second adhesive layer formed using a second adhesive composition; and Back panel, where, In the same manner as the thickness of the first adhesive reference layer and the thickness of the second adhesive reference layer, the first adhesive composition is used to form the first adhesive reference layer, and the second adhesive composition is used to form In the case of the second adhesive reference layer, the first adhesive reference layer and the second adhesive reference layer satisfy the relationship of the following formula (1): ΔR1>ΔR2 (1) [In formula (1), ΔR1 represents the value obtained by subtracting R1B from R1A, ΔR2 represents the value obtained by subtracting R2B from R2A, The R1A represents the shear creep value per 1 μm thickness at 25° C., which is the first shear creep rate (%/μm), calculated for the first adhesive reference layer after performing the strain repeated application test , The R1B represents the shear creep value per 1 μm thickness at 25°C calculated for the first adhesive reference layer before performing the strain repeated application test, that is, the second shear creep rate (%/μm) , The R2A represents the third shear creep rate (%/μm), which is the shear creep value per 1 μm thickness at 25°C, calculated for the second adhesive reference layer after the strain repeated application test , The R2B represents the fourth shear creep rate (%/μm), which is the shear creep value per 1 μm thickness at 25°C, calculated for the second adhesive reference layer before performing the repeated strain application test ]. [2] The laminate according to [1], wherein the fourth shear creep rate (%/μm) is 0.1 or more and 0.2 or less. [3] The laminate according to [1] or [2], wherein the thickness of at least one of the first adhesive layer and the second adhesive layer is 20 μm or more and 50 μm or less. [4] The laminate according to any one of [1] to [3], wherein there is one or more retardation layers between the polarizer layer and the back plate. [5] The laminate according to any one of [1] to [4], wherein the back panel is a touch sensor panel. [6] A display device comprising the laminate as described in any one of [1] to [5]. [7] The display device according to [6], wherein the front panel side can be bent on the outside. [Effects of the invention]

According to the present invention, it is possible to provide a laminate having improved durability by suppressing the generation of bubbles in an adhesive layer, and a display device including the laminate.

Hereinafter, a laminate according to an embodiment of the present invention (hereinafter also simply referred to as "laminate") will be described with reference to the drawings.

〔Laminated body〕 Fig. 1 shows a schematic cross-sectional view of a laminate according to an embodiment of the present invention. The laminated body 100 includes in order: a front surface plate 101; a first adhesive layer 102 formed using a first adhesive composition; a polarizer layer 103; a second adhesive layer 104 formed using a second adhesive composition; and The back panel 105. Hereinafter, the first adhesive layer 102 and the second adhesive layer 104 are sometimes collectively referred to as "adhesive layer".

The thickness of the layered body 100 varies depending on the functions required for the layered body and the purpose of the layered body, and therefore is not particularly limited. For example, it is 30 μm or more and 1500 μm or less, preferably 40 μm or more and 1000 μm or less, and more It is preferably 50 μm or more and 500 μm or less.

The planar shape of the laminate 100 may be, for example, a square shape, preferably a square shape having long sides and short sides, and more preferably a rectangular shape. When the shape of the laminate 100 in the plane direction is a rectangle, the length of the long side may be, for example, 10 mm or more and 1400 mm or less, and preferably 50 mm or more and 600 mm or less. The length of the short side may be, for example, 5 mm or more and 800 mm or less, preferably 30 mm or more and 500 mm or less, and more preferably 50 mm or more and 300 mm or less. Each layer constituting the layered body may be R processed at the corners, cut at the ends, or drilled.

The laminated body 100 can be applied to a display device or the like, for example. The display device is not particularly limited, and examples thereof include organic electroluminescence (organic electroluminescence, organic EL) display devices, inorganic electroluminescence (inorganic EL) display devices, liquid crystal display devices, electroluminescence display devices, and the like. The display device may have a touch panel function. Furthermore, the display device to which the laminate 100 is applied can be used as a flexible display that can be bent, wound, or the like. The display device is preferably capable of bending the front surface plate 101 side to the outside. However, the laminated body 100 can also be bent with the front surface plate 101 side inside.

[Adhesive layer (first adhesive layer formed using the first adhesive composition, and second adhesive layer formed using the second adhesive composition)] As described above, the laminate 100 includes the first adhesive layer 102 formed using the first adhesive composition, and the second adhesive layer 104 formed using the second adhesive composition. In the laminate 100, the following relationship is established between the first adhesive composition used to form the first adhesive layer 102 and the second adhesive composition used to form the second adhesive layer 104. That is, in such a way that the thickness of the first adhesive reference layer is the same as the thickness of the second adhesive reference layer, the first adhesive composition is used to form the first adhesive reference layer, and the second adhesive composition is used When the substance forms the second adhesive reference layer, the first adhesive reference layer and the second adhesive reference layer satisfy the relationship of the following formula (1). The thickness of the first adhesive reference layer and the thickness of the second adhesive reference layer may be 200 μm, for example. ΔR1>ΔR2 (1) [In formula (1), ΔR1 represents the value obtained by subtracting R1B from R1A, ΔR2 represents the value obtained by subtracting R2B from R2A, R1A represents the first shear creep rate (%/μm), which is the shear creep value per 1 μm thickness at 25°C calculated for the first adhesive reference layer after the repeated strain application test, R1B represents the second shear creep rate (%/μm), which is the shear creep value per 1 μm thickness at 25°C calculated for the first adhesive reference layer before performing the repeated strain application test, R2A represents the third shear creep rate (%/μm) at 25°C per 1 μm thickness calculated for the second adhesive reference layer after the repeated strain application test, R2B represents the fourth shear creep rate (%/μm), which is the shear creep value per 1 μm thickness at 25° C., calculated for the second adhesive reference layer before the repeated strain application test.

Furthermore, the shear creep value (%) at 25°C, the first shear creep rate of R1A (%/μm), the second shear creep rate of R1B (%/μm), and R2A The third shear creep rate (%/μm) of R2B and the fourth shear creep rate (%/μm) representing R2B can be determined according to the measurement method described in the column of Examples described later.

In the laminate 100, the first adhesive layer 102 and the second adhesive layer 104 as the adhesive layers contained therein can be formed by using the first adhesive reference layer that satisfies the relationship of the formula (1) and The first adhesive composition and the second adhesive composition of the second adhesive reference layer are formed. In this case, the laminate 100 can improve durability by suppressing the generation of bubbles in the adhesive layer. In particular, when bending the front surface plate 101 side to the outside, the laminate 100 can further suppress the generation of bubbles in the adhesive layer. Therefore, the laminated body 100 is suitable for use in a laminated body of a method in which the front surface plate side is bent outward (a so-called outfolding method), and a display device including the same.

The first adhesive layer 102 and the second adhesive layer 104 are respectively composed of a first adhesive composition and a first adhesive composition capable of forming a first adhesive reference layer and a second adhesive reference layer that satisfy the relationship of the formula (1) When the second adhesive composition is formed, although the details of the reason why the above-mentioned effect can be obtained are not clear, it is considered to be due to the following mechanism. First, in the course of research conducted by the inventors of the present invention, it was found that when the laminated body is bent by making the front surface plate side the outer side, air bubbles may sometimes be generated in the adhesive layer. Regarding the location where bubbles are generated in this case, it can be seen that most of them are the adhesive layer on the side away from the front surface plate, that is, the second adhesive layer side.

Here, in the case where the first adhesive reference layer and the second adhesive reference layer satisfy the relationship of the formula (1), the second adhesive composition refers to the phase with the first adhesive composition Compared with the composition before and after repeated strain application, the change in shear creep rate (%/μm) is smaller. Furthermore, the feature that the shear creep rate (%/μm) has a smaller change means that it can resist external stress and maintain the inherent properties of the adhesive layer (that is, durability). Therefore, it is believed that the adhesive layer formed by using the second adhesive composition (second adhesive layer 104) can achieve better performance than the adhesive layer formed by using the first adhesive composition (first adhesive layer 102). The bending durability is more excellent.

Based on the above, as an adhesive layer away from the side of the front surface plate where air bubbles are frequent when the laminate is bent when the front surface plate side is the outer side, the inventors of the present invention arrange the use of a second adhesive that is more durable to bending An adhesive layer (second adhesive layer 104) formed by an adhesive composition. Thereby, when the laminated body 100 is bent by making the front surface plate 101 side the outer side, the laminated body 100 which can suppress the generation of bubbles in an adhesive layer is achieved. Specifically, as shown in the embodiment described later, the laminated body 100 is provided with a mandrel (mandrel), which is a cylindrical jig with a diameter (Φ) exceeding 10 mm and 15 mm or less, on the inner side of the back plate 105 side. When the laminated body 100 is bent along the mandrel, the generation of bubbles in the adhesive layer can also be suppressed (this performance is also referred to as "excellent bending durability" below).

In this specification, "curved" includes a form of bending where a curved portion is formed. In the form of bending, the radius of curvature of the inner surface of the bending is not limited unless otherwise specified. In addition, as long as there is no special description, "curve" includes a form of bending where the bending angle of the inner surface is greater than 0 degrees and less than 180 degrees, and the radius of curvature of the inner surface is approximately zero, or the bending angle of the inner surface is 0. Degree of folded form.

The values of ΔR1 and ΔR2 are respectively preferably 0.01 to 4, more preferably 0.05 to 0.5, and still more preferably 0.05 to 0.2.

The first shear creep rate R1A (%/μm) is preferably 0.05 to 1.0, more preferably 0.2 to 0.5. The second shear creep rate R1B (%/μm) is preferably 0.01 to 0.3, more preferably 0.05 to 0.2. The third shear creep rate R2A (%/μm) is preferably 0.05 to 1.0, more preferably 0.2 to 0.5. The fourth shear creep rate R2B (%/μm) is preferably 0.01 to 0.3, more preferably 0.05 to 0.2.

In the laminate 100, the fourth shear creep rate (%/μm) is preferably 0.1 or more and 0.2 or less. In this case, the second adhesive layer 104 is an adhesive layer that has moderate hardness in addition to excellent flexibility and durability, and therefore can impart excellent surface hardness to the laminate 100. Specifically, as shown in the following examples, when a pencil with a core hardness of 6B is used to apply a load of 100 g to the surface of the back plate 105 of the laminate 100, the traces of the recesses formed on the surface can be made It disappears in less than 1 hour (this performance is also referred to as "excellent surface hardness" below).

The gel fraction of the adhesive layer can be 40% to 90%, or 50% to 80%. The gel fraction of the adhesive layer is measured by the method described in the following Examples.

Furthermore, in the laminate 100, it is preferable that the thickness of at least one of the first adhesive layer 102 and the second adhesive layer 104 is 20 μm or more and 50 μm or less.

Here, as the preparation method of the first adhesive composition and the second adhesive composition constituting the first adhesive reference layer and the second adhesive reference layer satisfying the relationship of the formula (1), for example, The adhesive composition A described later constitutes these, or the type of monomer constituting the (meth)acrylic polymer A described later is changed, or the molecular weight of the (meth)acrylic polymer A is adjusted. Hereinafter, the adhesive composition A will be specifically described.

＜Adhesive composition A＞ Although the composition of the first adhesive layer 102 and the second adhesive layer 104 are different, they can be composed of an adhesive composition containing (meth)acrylic polymer (hereinafter also referred to as "adhesive Agent composition A”) is formed. The adhesive composition A may be an active energy ray hardening type or a thermosetting type. The "(meth)acrylic polymer" in this specification means at least one selected from the group consisting of acrylic polymers and methacrylic polymers. The same applies to other terms with "(methyl)". Regarding the first adhesive composition and the second adhesive composition, when both of them contain a (meth)acrylic polymer, the (meth)acrylic polymer may be the same or different. Hereinafter, the (meth)acrylic polymer contained in the adhesive composition A is also referred to as "(meth)acrylic polymer A".

(Active energy ray hardening adhesive composition) When the adhesive composition A is an active energy ray-curable adhesive composition, the (meth)acrylic polymer A contained in the adhesive composition A is derived from a monomer having a reactive functional group The structural unit of is preferably 1% by mass or less based on the total mass of the polymer. Examples of the reactive functional group include a hydroxyl group, a carboxyl group, an amino group, an amide group, and an epoxy group. Thereby, the flexibility of the adhesive layer is improved, and there is a tendency to easily suppress the generation of bubbles in the adhesive layer at room temperature. In the (meth)acrylic polymer A, from the viewpoint of suppressing the generation of bubbles during bending, the constituent unit derived from a monomer having a reactive functional group is more preferably 0.01 mass based on the total mass of the polymer % Or less, it is more preferable not to have the structural unit derived from the monomer which has a reactive functional group, and it is still more preferable not to have a hydroxyl group, a carboxyl group, an amino group, an amido group, and an epoxy group.

The (meth)acrylic polymer A may include the following structural unit derived from a (meth)acrylic monomer having a linear or branched alkyl group having 1 to 24 carbon atoms . As the (meth)acrylic monomer having a linear or branched alkyl group having 1 to 24 carbon atoms, for example, alkyl (meth)acrylate, etc., and examples thereof include : Butyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, ( Isooctyl meth)acrylate, isodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, and the like. The (meth)acrylic polymer A may be a polymer or copolymer containing one or two or more of the alkyl (meth)acrylate as a monomer. The content of the (meth)acrylic polymer A in the adhesive composition A can be, for example, 50% by mass or more and 100% by mass or less, and preferably 80% by mass relative to 100 parts by mass of the solid content of the adhesive composition A % Or more and 99.5% by mass or less, more preferably 90% by mass or more and 99% by mass or less.

The weight average molecular weight (Mw) of the (meth)acrylic polymer A may be, for example, 100,000 or more and 2 million or less, and from the viewpoint of suppressing bubbles at the time of bending, it is preferably 500,000 or more and 1.5 million or less. The weight average molecular weight in this specification can be calculated based on a standard polystyrene conversion value measured by a gel permeation chromatography (GPC) method as explained in the column of Examples described later.

The adhesive composition A may contain one or two or more (meth)acrylic polymers A. Furthermore, the adhesive composition A may contain only the (meth)acrylic polymer A as its constituent component, or may further contain a crosslinking agent. Examples of the crosslinking agent include: a metal ion having a valence of two or more and forming a metal carboxylic acid salt with a carboxyl group; a polyamine compound forming an amide bond with a carboxyl group; a polyepoxy compound or Polyols and those that form ester bonds with carboxyl groups; those that are polyisocyanate compounds and those that form amide bonds with carboxyl groups. Among them, polyisocyanate compounds are preferred. When the adhesive composition A contains a crosslinking agent, the content of the crosslinking agent can be, for example, 5 parts by mass or less, preferably 3 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic polymer A , More preferably 1 part by mass or less, and still more preferably 0.5 part by mass or less. The adhesive composition A sometimes does not contain a crosslinking agent.

The so-called active energy ray curable adhesive composition means that it has the property of being cured by irradiation of active energy rays such as ultraviolet rays or electron rays, and has adhesiveness even before the active energy rays are irradiated, so that it can bond with the film. Adhesive composition that is in close contact with the adherend and is cured by the irradiation of active energy rays to adjust the properties such as adhesion. The active energy ray curable adhesive composition is preferably an ultraviolet curable adhesive composition.

When the adhesive composition A is an active energy ray curable adhesive composition, the adhesive composition A may further contain an active energy ray polymerizable compound, a photopolymerization initiator, a photosensitizer, and the like.

As the active energy ray polymerizable compound, for example, a (meth)acrylate monomer having at least one (meth)acryloyloxy group in the molecule; obtained by reacting two or more functional group-containing compounds, and The (meth)acrylate oligomer having at least two (meth)acryloxy groups and the like are (meth)acrylic compounds such as (meth)acryloxy group-containing compounds. With respect to 100 parts by mass of the solid content of the adhesive composition A, the adhesive composition A may contain 0.1 parts by mass or more and 10 parts by mass or less of the active energy ray polymerizable compound.

As a photopolymerization initiator, benzophenone, benzil dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, etc. are mentioned, for example. When the adhesive composition A contains a photopolymerization initiator, it may contain one kind or two or more kinds. When the adhesive composition A contains a photopolymerization initiator, the total content thereof may be 0.01 part by mass or more and 1.0 part by mass or less with respect to 100 parts by mass of the solid content of the adhesive composition A, for example.

The adhesive composition A may contain fine particles, beads (resin beads, glass beads, etc.), glass fibers, resins other than raw polymers, adhesiveness imparting agents, fillers (metal powder or other inorganic powders) for imparting light scattering properties Etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, defoamers, anti-corrosion agents and other additives. From the viewpoint of preventing the problem of durability reduction caused by the residual solvent, the adhesive composition A preferably does not contain an organic solvent.

When the adhesive layer is formed of the adhesive composition A, the adhesive layer can be formed by coating the adhesive composition A on the substrate. In the case of using an active energy ray-curable adhesive composition, the formed adhesive layer can be irradiated with active energy rays to produce a cured product having a desired degree of curing.

(Thermosetting adhesive composition) When the adhesive composition A is a thermosetting adhesive composition, the (meth)acrylic polymer A is preferably an alkyl (meth)acrylate having 2 to 20 carbon atoms, And a monomer having a reactive functional group in the molecule (a monomer containing a reactive functional group) is used as a monomer unit constituting the polymer. In the case of a thermosetting adhesive composition, the adhesive composition A preferably further contains a thermal crosslinking agent.

The (meth)acrylic polymer A has an alkyl (meth)acrylic acid alkyl ester having 2 to 20 carbon atoms as a monomer unit constituting the polymer, and can exhibit better adhesiveness. The alkyl (meth)acrylate having 2 to 20 carbon atoms in the alkyl group preferably contains, for example, a homopolymer having a glass transition temperature (Tg) of -40°C or less (hereinafter sometimes referred to as "low Tg acrylic alkyl ester"). By containing the low Tg alkyl acrylate as a constituent monomer unit, the flexibility of the adhesive layer is improved, and therefore, the generation of bubbles during bending can be more easily suppressed. The glass transition temperature (Tg) of the (meth)acrylic polymer A can be obtained by using a conventionally known method such as differential thermal analysis (DTA).

As low Tg alkyl acrylates, for example, n-butyl acrylate (Tg is -54°C), n-octyl acrylate (Tg is -65°C), isooctyl acrylate (Tg is -58°C) , 2-ethylhexyl acrylate (Tg is -70℃), isononyl acrylate (Tg is -58℃), isodecyl acrylate (Tg is -60℃), isodecyl methacrylate (Tg is- 41℃), n-lauryl methacrylate (Tg is -65℃), tridecyl acrylate (Tg is -55℃), tridecyl methacrylate (-40℃), etc. Among them, as the low-Tg alkyl acrylate, the homopolymer has a Tg of -45°C or lower, and particularly preferably -50°C or lower. Specifically, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred. These can be used alone or in combination of two or more.

In the (meth)acrylic polymer A, as the monomer unit constituting the polymer, the following limit is preferably 85% by mass or more of low Tg alkyl acrylate, more preferably 90% by mass or more, and further It is preferable to contain 95% by mass or more.

Furthermore, in the (meth)acrylic polymer A, as a monomer unit constituting the polymer, it is preferable that the above-mentioned limit contains the low Tg alkyl acrylate in an amount of 99.9% by mass or less, and more preferably 99.5 mass%. % Or less, more preferably 99% by mass or less. By containing the low Tg alkyl acrylate at 99.9% by mass or less, an appropriate amount of other monomer components (especially a monomer containing a reactive functional group) can be introduced into the (meth)acrylic polymer A.

From the viewpoint of further exerting the effects of the present invention, the (meth)acrylic polymer A preferably has as little as possible a homopolymer whose glass transition temperature (Tg) exceeds 0°C (hereinafter sometimes referred to as "Hard monomer") content. Specifically, in the (meth)acrylic polymer A, as a monomer unit constituting the polymer, the content of the hard monomer is preferably set to 15% by mass or less, more preferably 10 Mass% or less, more preferably 5 mass% or less. This hard monomer also includes the reactive functional group-containing monomer described later.

As the hard monomer, for example, methyl acrylate (Tg is 10°C), methyl methacrylate (Tg is 105°C), ethyl methacrylate (Tg is 65°C), n-butyl methacrylate Esters (Tg is 20°C), isobutyl methacrylate (Tg is 48°C), tertiary butyl methacrylate (Tg is 107°C), n-stearyl acrylate (Tg is 30°C), methacrylic acid Stearyl ester (Tg is 38°C), cyclohexyl acrylate (Tg is 15°C), cyclohexyl methacrylate (Tg is 66°C), phenoxyethyl acrylate (Tg is 5°C), methyl Phenoxyethyl acrylate (Tg is 54°C), benzyl methacrylate (Tg is 54°C), isobornyl acrylate (Tg is 94°C), isobornyl methacrylate (Tg is 180°C), acrylic Acrylic morpholine (Tg is 145°C), adamantyl acrylate (Tg is 115°C), adamantyl methacrylate (Tg is 141°C), acrylic acid (Tg is 105°C), dimethyl acrylate Acrylic monomers such as amine (Tg: 89°C), acrylamide (Tg: 165°C), vinyl acetate (Tg: 32°C), styrene (Tg: 80°C), etc.

The (meth)acrylic polymer A contains a reactive functional group-containing monomer as a monomer unit constituting the polymer, and passes through the reactive functional group derived from the reactive functional group-containing monomer to be described later The thermal crosslinker reaction. Thereby, a crosslinked structure (three-dimensional network structure) is formed as a whole, and an adhesive having a desired cohesive force can be obtained.

Examples of the reactive functional group-containing monomer contained in the (meth)acrylic polymer A as a monomer unit constituting the polymer include: monomers having a hydroxyl group in the molecule (a hydroxyl group-containing monomer Monomers), monomers having carboxyl groups in the molecule (carboxyl group-containing monomers), monomers having amine groups in the molecule (amine group-containing monomers), etc. Among these, in many cases where the glass transition temperature (Tg) is 0°C or less, a hydroxyl group-containing monomer is particularly preferred.

Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2 (meth)acrylic acid. -Hydroxyalkyl (meth)acrylates such as hydroxybutyl, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. Among them, in terms of the glass transition temperature (Tg), the reactivity of the hydroxyl group in the obtained (meth)acrylic polymer A with the thermal crosslinking agent, and the copolymerizability with other monomers, it is preferably At least one of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, and 4-hydroxybutyl acrylate. These can be used alone or in combination of two or more.

Examples of carboxyl group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These can be used alone or in combination of two or more.

Examples of the amine group-containing monomer include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These can be used alone or in combination of two or more.

In the (meth)acrylic polymer A, as the monomer unit constituting the polymer, the following limit is preferably 0.1% by mass or more of the reactive functional group-containing monomer, particularly preferably 0.5% by mass or more , It is more preferable to contain 1% by mass or more. In the (meth)acrylic polymer A, the above limit is preferably 10% by mass or less of the reactive functional group-containing monomer, particularly preferably 8% by mass or less, and more preferably 5% by mass the following. This tends to more easily suppress the generation of bubbles during bending.

In the (meth)acrylic polymer A, as a monomer unit constituting the polymer, a carboxyl group-containing monomer, particularly acrylic acid which is also a hard monomer, may not be contained. The carboxyl group is an acid component. Therefore, by not containing a carboxyl group-containing monomer, even if there is a problem caused by acid in the object of the adhesive, such as tin-doped indium oxide (indium tin oxide, ITO )) In the case of transparent conductive films, metal films, metal meshes, etc., it is also possible to suppress these disadvantages (corrosion, resistance value changes, etc.) due to acid.

The (meth)acrylic polymer A may also contain other monomers as monomer units constituting the polymer as necessary. As other monomers, in order not to interfere with the function of the reactive functional group-containing monomer, it is also preferable that the monomer does not contain a reactive functional group. As the other monomers, for example, in addition to alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, homopolymers can be cited A monomer whose glass transition temperature (Tg) exceeds -40°C and is below 0°C (hereinafter sometimes referred to as "medium Tg alkyl acrylate" etc.. Medium Tg alkyl acrylates include, for example, ethyl acrylate ( Tg is -20℃), isobutyl acrylate (Tg is -26℃), 2-ethylhexyl methacrylate (Tg is -10℃), n-lauryl acrylate (Tg is -23℃), isobutyl acrylate Stearyl ester (Tg is -18°C), etc. These can be used alone or in combination of two or more.

The polymerization state of (meth)acrylic polymer A may be a random copolymer or a block copolymer.

The lower limit of the weight average molecular weight of the (meth)acrylic polymer A is preferably 200,000 or more, particularly preferably 300,000 or more, and still more preferably 400,000 or more. If the lower limit of the weight average molecular weight of the (meth)acrylic polymer A is more than the above, it is possible to suppress defects such as leaching of the adhesive. The weight average molecular weight in this specification can be calculated|required based on the value of the standard polystyrene conversion measured by the gel permeation chromatography (GPC) method as demonstrated in the column of an Example mentioned later.

The upper limit of the weight average molecular weight of the (meth)acrylic polymer A is preferably 2 million or less, particularly preferably 1.5 million or less, and more preferably 1.3 million or less. If the upper limit value of the weight average molecular weight of the (meth)acrylate polymer (A) is the above-mentioned or less, the flexibility of the adhesive layer can be ensured, and the effect of the present invention can be easily exhibited.

In the adhesive composition A, (meth)acrylic polymer A may be used alone or in combination of two or more.

When the adhesive composition A containing the thermal crosslinking agent is heated, the thermal crosslinking agent crosslinks the (meth)acrylic polymer A to form a three-dimensional network structure. Thereby, the cohesive force can be improved while ensuring the flexibility of the adhesive, and when applied to a laminate, it is possible to obtain a hardness that can increase the surface hardness of the laminate.

The thermal crosslinking agent may be one that reacts with the reactive group possessed by the (meth)acrylic polymer A, and examples thereof include isocyanate crosslinking agents, epoxy crosslinking agents, and amine crosslinking agents. Linking agent, melamine-based cross-linking agent, aziridine-based cross-linking agent, hydrazine-based cross-linking agent, aldehyde-based cross-linking agent, oxazoline-based cross-linking agent, metal alkoxide-based cross-linking agent, metal chelate Crosslinking agent, metal salt crosslinking agent, ammonium salt crosslinking agent, etc. Among the above, when the reactive group possessed by the (meth)acrylic polymer A is a hydroxyl group, it is preferable to use an isocyanate-based crosslinking agent having excellent reactivity with the hydroxyl group. The thermal crosslinking agent may be used alone or in combination of two or more.

The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; isophorone diisocyanate, Hydrogenated diphenylmethane diisocyanate and other alicyclic polyisocyanates, etc.; and these biuret bodies, isocyanurate bodies, and as a combination with ethylene glycol, propylene glycol, neopentyl glycol, and trimethylolpropane , Castor oil and other adducts of the reaction products of compounds containing low molecular active hydrogen. Among them, from the viewpoint of reactivity with hydroxyl groups, aromatic polyisocyanates modified with trimethylolpropane are preferred, and toluene diisocyanate modified with trimethylolpropane and trimethylolpropane modified are particularly preferred. Xylylene diisocyanate.

As an epoxy-based crosslinking agent, for example, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl- M-xylylenediamine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidyl amine, etc.

Relative to 100% by mass of the (meth)acrylic polymer A, the content of the thermal crosslinking agent in the adhesive composition A is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass %the above. Furthermore, the content is preferably 1% by mass or less, more preferably 0.8% by mass or less, and still more preferably 0.5% by mass or less. When the content of the thermal crosslinking agent is in the above-mentioned range, it is possible to more easily obtain a moderate hardness by improving the cohesive force.

The adhesive composition A preferably contains the silane coupling agent. Thereby, the adhesiveness of the obtained adhesive bond layer and each member in the laminated body which is an adherend improves, and the durability to bending becomes more excellent.

As a silane coupling (SC) agent, it is preferably an organosilicon compound with at least one alkoxysilyl group in the molecule, and has good compatibility with (meth)acrylic polymer A and has light transmittance Sexual silane coupling agent.

Examples of the silane coupling agent include: vinyl trimethoxy silane, vinyl triethoxy silane, methacryloxypropyl trimethoxy silane, and other polymerizable unsaturated group-containing silicon compounds; 3-condensation Silicon compounds with epoxy structure such as glyceroxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc.; 3-mercaptopropyltrimethoxysilane, 3-mercapto Sulfhydryl-containing silicon compounds such as propyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane, etc.; 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3 -Aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and other amino-containing silicon compounds; 3-chloropropyltrimethoxy Silane, 3-isocyanate propyltriethoxysilane, or at least one of these and methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. Condensates of alkyl-containing silicon compounds, etc. These can be used alone or in combination of two or more.

Relative to 100% by mass of the (meth)acrylic polymer A, the content of the silane coupling agent in the adhesive composition A is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass the above. Furthermore, the content is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably 0.3% by mass or less. When the content of the silane coupling agent is in the above range, the adhesiveness with each member in the laminate can be further improved.

In the adhesive composition A, the various additives described above can be added as necessary. In this specification, the polymerization solvent and the dilution solvent are regarded as not included in the additives constituting the adhesive composition A.

The (meth)acrylic polymer A can be produced by polymerizing a mixture of monomers constituting the polymer by a normal radical polymerization method. The polymerization of the (meth)acrylic polymer A is preferably carried out by a solution polymerization method using a polymerization initiator as necessary. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, etc. are mentioned, for example, You may use 2 or more types together.

Examples of the polymerization initiator include azo compounds, organic peroxides, and the like, and two or more of them may be used in combination. As the azo compound, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane 1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxypentane) Nitrile), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis( 2-hydroxymethylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] and the like.

Examples of organic peroxides include: benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, peroxy Di(2-ethoxyethyl) oxydicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxyvalerate, peroxide (3,5,5-trimethylhexyl) , Dipropylene peroxide, diacetyl peroxide, etc.

In the polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by formulating a chain transfer agent such as 2-mercaptoethanol.

After obtaining the (meth)acrylic polymer A, add a thermal crosslinking agent, a silane coupling agent, and additives and diluent solvents as necessary to the solution of the (meth)acrylic polymer A, and mix them thoroughly, thereby The adhesive composition A (coating solution) diluted with a solvent can be obtained. The adhesive composition A can be produced by mixing the components together using a known method, for example, using a mixer. Furthermore, the first adhesive composition and the second adhesive composition can be prepared from the adhesive composition A obtained in this way.

In any of the above-mentioned components, when a solid one is used, or when precipitation occurs when mixed with other components in an undiluted state, the component may be separately dissolved or diluted in advance Dilute the solvent and mix with other ingredients.

As the diluent solvent, for example, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane and dichloroethane; methanol, ethanol, and propylene Alcohol, butanol, 1-methoxy-2-propanol and other alcohols; acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone and other ketones; ethyl acetate, butyl acetate, etc. Esters; Ethyl siloxu and other siloxus-based solvents.

The concentration and viscosity of the adhesive composition A (coating solution) prepared in this manner are not particularly limited as long as they are in a range that can be applied, and can be appropriately selected according to the situation. For example, it can be prepared as the concentration of the adhesive composition A in a solution of 10% by mass to 60% by mass. When the coating solution is obtained, the addition of a dilution solvent or the like is not essential, and if the adhesive composition A has a viscosity or the like that can be applied, the dilution solvent may not be added. In this case, the adhesive composition A becomes a coating solution in which the polymerization solvent of the (meth)acrylic polymer A is directly used as a diluting solvent.

The adhesive layer can be obtained by crosslinking the adhesive composition A. The crosslinking of the adhesive composition A can be performed by heat treatment. The heat treatment can also be used as a drying treatment at the time of volatilizing the coating film of the adhesive composition A obtained by applying a dilution solvent or the like to a desired object.

The heating temperature of the heat treatment is preferably 50°C to 150°C, more preferably 70°C to 120°C. The heating time of the heat treatment is preferably 10 seconds to 10 minutes, more preferably 50 seconds to 2 minutes.

After the heat treatment, if necessary, a curing period of about 1 to 2 weeks may be set at normal temperature (for example, 23° C., 50% RH). In the case where the curing period is required, the adhesive layer can be formed after the curing period has passed. In the case where the curing period is not required, the adhesive layer can be formed after the heat treatment is completed.

By the heat treatment (and curing), the (meth)acrylic polymer A is sufficiently cross-linked via the cross-linking agent, thereby forming a cross-linked structure, thereby obtaining an adhesive layer (first adhesive layer 102 And the second adhesive layer 104).

＜Adhesive sheet＞ The adhesive sheet may include an adhesive layer formed of the adhesive composition A. The adhesive layer can be formed by coating the adhesive composition A on the substrate. In the case of using an active energy ray curable adhesive composition as the adhesive composition A, by irradiating the formed adhesive layer with active energy rays, a cured product having a desired degree of curing can be obtained. In the case of using a thermosetting adhesive composition as the adhesive composition, heat treatment (and curing) of the formed adhesive layer can produce a cured product having a desired degree of curing.

The substrate may be a release film that has been subjected to mold release treatment. The adhesive sheet can be produced by coating the adhesive composition A on the release film to form the adhesive layer into a sheet shape, and then attaching another release film on the adhesive layer.

As a method of applying the coating liquid of the adhesive composition A, for example, a bar coating method, a knife coating method, a roll coating method, a knife coating method, a die coating method, a gravure coating method, etc. can be used.

[Front Panel] As long as the front surface plate 101 is a plate-shaped body capable of transmitting light, the material and thickness are not limited, and may include only one layer, or two or more layers. As an example, a resin plate-shaped body (for example, a resin plate, a resin sheet, a resin film, etc.), a glass plate-shaped body (for example, a glass plate, a glass film, etc.), and the touch sensor panel mentioned later can be mentioned. The front surface plate may be the most surface of the display device.

The thickness of the front surface plate 101 may be, for example, 10 μm or more and 1000 μm or less, preferably 20 μm or more and 500 μm or less, and more preferably 30 μm or more and 300 μm or less. In the present invention, the thickness of each layer can be measured in accordance with the thickness measurement method described in the following Examples.

In the case where the front surface plate 101 is a plate-shaped body made of resin, the plate-shaped body made of resin is not limited as long as it can transmit light. Examples of the resin constituting the plate-shaped body made of resin such as resin film include triacetyl cellulose, acetyl cellulose butyrate, ethylene-vinyl acetate copolymer, acryl-based cellulose, butyl-based cellulose, Acetyl propylene cellulose, polyester, polystyrene, polyamide, polyetherimide, poly(meth)acrylic acid, polyimide, polyether chrysene, poly chrysene, polyethylene, polypropylene , Polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether ash, polymethyl methacrylate, polyterephthalate Films formed of polymers such as ethylene formate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyamide imide. These polymers can be used alone or in combination of two or more. From the viewpoint of improving strength and transparency, a resin film formed of a polymer such as polyimide, polyimide, and polyimide is preferred.

From the viewpoint of hardness, the front surface plate 101 is preferably a film in which a hard coat layer is provided on at least one surface of a base film. As the base film, a film made of the resin can be used. The hard coat layer can be formed on one side of the base film or on both sides. By providing a hard coat layer, a resin film with improved hardness and scratch resistance can be made. The hard coat layer is, for example, a cured layer of ultraviolet curable resin. Examples of ultraviolet curable resins include acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins. In order to increase the strength, the hard coat layer may contain additives. The additives are not limited, and examples include inorganic fine particles, organic fine particles, or a mixture of these.

In the case where the front surface plate 101 is a glass plate, the glass plate is preferably a tempered glass for display. The thickness of the glass plate may be, for example, 10 μm or more and 1000 μm or less, and may be 50 μm or more and 1000 μm or less. By using a glass plate, the front surface plate 101 having excellent mechanical strength and surface hardness can be constructed.

In the case where the laminated body 100 is used in a display device, the front surface plate 101 may not only have a function of protecting the front surface (screen) of the display device (function as a window film), but also have a function as a touch sensor, Blu-ray cutoff function, viewing angle adjustment function, etc.

[The first adhesive layer] The first adhesive layer 102 is a layer that is interposed between the front surface plate 101 and the polarizer layer 103 and is bonded together. For example, it may be a layer containing an adhesive or an adhesive or be formed by performing some treatment on the layer.的层。 The layer. The first adhesive layer 102 may be an adhesive layer arranged at a position closest to the front surface plate 101 among the adhesive layers constituting the laminated body 100. Here, the "adhesive" in this specification is also referred to as a pressure-sensitive adhesive. Furthermore, the "adhesive agent" in this specification refers to an adhesive agent other than an adhesive agent (pressure-sensitive adhesive agent), and is clearly distinguished from an adhesive agent. The first adhesive layer 102 may be one layer, or may include two or more layers, preferably one layer.

The first adhesive layer 102 can be formed using the first adhesive composition as described above. The first adhesive composition can be formed using the adhesive composition A as described above. In the first adhesive layer 102, the first adhesive composition is used to form the first adhesive reference layer in such a way that the thickness of the first adhesive reference layer is the same as the thickness of the second adhesive reference layer. When the two adhesive compositions form the second adhesive reference layer, the first adhesive reference layer and the second adhesive reference layer satisfy the relationship of formula (1) represented by ΔR1>ΔR2. The thickness of the first adhesive reference layer and the thickness of the second adhesive reference layer can be set to, for example, 200 μm. As long as the relationship between the first adhesive composition and the second adhesive composition satisfies the above formula (1), it is not limited to the adhesive composition A, and can be directly formed from any adhesive composition, or can be used with any It is formed by the adhesive sheet of the adhesive layer formed by the adhesive composition. However, the first adhesive composition is preferably formed of the adhesive composition A, or it is also preferably formed using an adhesive sheet formed by coating the adhesive composition A on a substrate.

That is, in the first adhesive layer 102, the composition and blending components of the first adhesive composition constituting the first adhesive layer 102, the type of the first adhesive composition (active energy ray hardening type, thermosetting type, etc.), can be adjusted to The additives in the first adhesive composition, the manufacturing method of the first adhesive layer, and the thickness of the first adhesive layer can be as described in [Adhesive layer (first adhesive formed using the first adhesive composition) Layer, and the second adhesive layer formed by using the second adhesive composition)].

In the laminate 100, it is preferable that the thickness of at least one of the first adhesive layer 102 and the second adhesive layer 104 is 20 μm or more and 50 μm or less. Therefore, the thickness of the first adhesive layer 102 may be, for example, 3 μm or more and 100 μm or less, preferably 5 μm or more and 50 μm or less, or 20 μm or more. Preferably, the thickness of the first adhesive layer 102 is 20 μm or more and 50 μm or less.

[Polarizer layer] As the polarizer layer 103, a stretched film or stretched layer to which a dichroic dye is adsorbed, a layer obtained by applying and curing a composition containing a dichroic dye and a polymerizable compound, and the like can be cited. As the dichroic dye, specifically, iodine or a dichroic organic dye can be used. Dichroic organic dyes include dichroic direct dyes containing C.I. DIRECT RED 39 and other bisazo compounds, and dichroic direct dyes containing compounds such as trisazo and tetrasazo.

Examples of the polarizer layer formed by coating and curing a composition containing a dichroic dye and a polymerizable compound include coating a composition containing a liquid crystal dichroic pigment, or containing a dichroic pigment and A polarizer layer containing a cured product of a polymerizable liquid crystal compound, such as a layer obtained by curing a polymerizable liquid crystal composition. Compared with a stretched film or stretched layer on which a dichroic dye is adsorbed, there is no restriction on the bending direction of the polarizer layer formed by coating and curing a composition containing a dichroic dye and a polymerizable compound. Better.

In the laminated body 100, the polarizer layer 103 can function as a circular polarizer by combining it with a retardation layer mentioned later, for example.

<Polarizer layer which is a stretched film or stretched layer> The polarizer layer of the stretched film that adsorbs the dichroic dye can usually be manufactured through the following steps: the step of uniaxially stretching the polyvinyl alcohol-based resin film; The step of dyeing the film to adsorb the dichroic pigment; the step of treating the polyvinyl alcohol resin film with the dichroic pigment adsorbed with the boric acid aqueous solution; and the step of washing with water after the treatment with the boric acid aqueous solution. The thickness of the polarizer layer 103 is, for example, 2 μm or more and 40 μm or less. The thickness of the polarizer layer 103 may be 5 μm or more, and may be 20 μm or less, further may be 15 μm or less, and further may be 10 μm or less.

Polyvinyl alcohol-based resin is obtained by saponifying polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and other monomers that can be copolymerized therewith can also be used. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 mol% or more and 100 mol% or less, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1,000 or more and 10,000 or less, preferably 1,500 or more and 5,000 or less.

The polarizer layer that is the stretched layer to which the dichroic dye is adsorbed can generally be manufactured through the following steps: a step of applying a coating liquid containing the polyvinyl alcohol-based resin on a base film; and laminating the resulting laminate The step of uniaxial stretching of the film; the step of dyeing the polyvinyl alcohol-based resin layer of the uniaxially stretched laminate film with a dichroic dye to adsorb the dichroic dye to prepare a polarizer; using boric acid The step of treating the film with the dichroic dye adsorbed by the aqueous solution; and the step of washing with water after the treatment with the aqueous boric acid solution. The polarizer layer which is the stretched layer to which the dichroic dye is adsorbed may be peeled and removed from the polarizer layer of the base film as needed. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film described later.

The polarizer layer, which is a stretched film or stretched layer, may be assembled in a laminate in a form in which a thermoplastic resin film is bonded on one or both sides. This thermoplastic resin film can function as a protective film for the polarizer layer 103 or a retardation film. The thermoplastic resin film may include, for example, polyolefin resins such as chain polyolefin resins (polypropylene resins, etc.), cyclic polyolefin resins (norbornene resins, etc.); cellulose resins such as triacetyl cellulose. Resins; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate resins; (meth)acrylic resins; or these The mixture of the film.

The thermoplastic resin film may or may not have a phase difference. From the viewpoint of thinning, the thickness of the thermoplastic resin film is generally 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less, and still more preferably 60 μm or less. The thickness of the thermoplastic resin film is usually 5 μm or more, preferably 20 μm or more. The thermoplastic resin film can be bonded to the polarizer layer 103 using an adhesive layer, for example.

<Polarizer layer formed by coating and curing a composition containing a dichroic dye and a polymerizable compound> Examples of the polarizer layer formed by applying and curing a composition containing a dichroic dye and a polymerizable compound include a composition containing a polymerizable dichroic dye having liquid crystallinity, or a composition containing a dichroic dye A polarizer layer containing a cured product of a polymerizable liquid crystal compound, such as a layer obtained by applying and curing a composition of a polymerizable liquid crystal to a base film.

The polarizer layer formed by coating and curing a composition containing a dichroic dye and a polymerizable compound may peel off the base film from the polarizer layer as needed. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film. The polarizer layer may include an alignment film. The alignment film can also be peeled off.

The polarizer layer formed by applying and curing a composition containing a dichroic dye and a polymerizable compound can be assembled in an optical laminate in a form in which a thermoplastic resin film is bonded on one or both sides. As the thermoplastic resin film, the same ones as those that can be used in the polarizer layer which is a stretched film or a stretched layer can be used. The thermoplastic resin film can be bonded to the polarizer layer using an adhesive layer, for example.

The polarizer layer formed by coating and hardening a composition containing a dichroic dye and a polymerizable compound can also form an overcoat (OC) layer as a protective layer on one or both sides. Examples include photocurable resins and water-soluble polymers. Examples of the photocurable resin include (meth)acrylic resins, urethane resins, (meth)acrylate urethane resins, epoxy resins, and silicone resins. Examples of water-soluble polymers include: poly(meth)acrylamide-based polymers; polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, (meth)acrylic acid or its anhydride- Vinyl alcohol polymers such as vinyl alcohol copolymers; carboxyvinyl polymers; polyvinylpyrrolidone; starches; sodium alginate; polyethylene oxide polymers, etc. The thickness of the OC layer is preferably 20 μm or less, more preferably 15 μm or less, further preferably 10 μm or less, may be 5 μm or less, and may be 0.05 μm or more, or may be 0.5 μm or more.

The thickness of the polarizer layer obtained by coating and curing a composition containing a dichroic dye and a polymerizable compound is usually 10 μm or less, preferably 0.5 μm or more and 8 μm or less, more preferably 1 μm or more and Below 5 μm.

[Second Adhesive Layer] The second adhesive layer 104 is an adhesive layer arranged between the polarizer layer 103 and the back plate 105. The second adhesive layer may be an adhesive layer arranged at a position closest to the back plate 105 among the adhesive layers constituting the laminate 100. The second adhesive layer 104 may be one layer, or may include two or more layers, preferably one layer.

The second adhesive layer 104 can be formed using the second adhesive composition as described above. The second adhesive composition can be formed using the adhesive composition A as described above. In the second adhesive layer 104, the second adhesive composition is used to form the second adhesive reference layer in such a way that the thickness of the first adhesive reference layer is the same as the thickness of the second adhesive reference layer, and the When the first adhesive composition forms the first adhesive reference layer, the first adhesive reference layer and the second adhesive reference layer satisfy the relationship of formula (1) represented by ΔR1>ΔR2. The thickness of the first adhesive reference layer and the thickness of the second adhesive reference layer can be set to, for example, 200 μm. As long as the relationship between the second adhesive composition and the first adhesive composition satisfies the above formula (1), it is not limited to the adhesive composition A, and can be directly formed from any adhesive composition, or can be used with any It is formed by the adhesive sheet of the adhesive layer formed by the adhesive composition. However, the second adhesive composition is preferably formed of the adhesive composition A, or it is also preferably formed using an adhesive sheet formed by coating the adhesive composition A on a substrate.

That is, although the composition of the second adhesive layer 104 and the first adhesive layer 102 are different, they are preferably formed of the adhesive composition A in common. Therefore, in the second adhesive layer 104, regarding the composition and blending components of the second adhesive composition constituting it, the type of the second adhesive composition (whether it is an active energy ray hardening type or a thermosetting type, etc.), the first The adjustable additives in the second adhesive composition, the manufacturing method of the second adhesive layer, and the thickness of the second adhesive layer, etc. can be as described in [Adhesive layer (first adhesive formed using the first adhesive composition) The agent layer and the second adhesive layer formed using the second adhesive composition)] are as explained in the column.

In the laminate 100, it is preferable that the thickness of at least one of the first adhesive layer 102 and the second adhesive layer 104 is 20 μm or more and 50 μm or less. Therefore, the thickness of the second adhesive layer 104 may be, for example, 3 μm or more and 100 μm or less, preferably 5 μm or more and 50 μm or less, or 20 μm or more. Preferably, the thickness of the second 104 is 20 μm or more and 50 μm or less.

[Back Panel] As the back plate 105, a plate-shaped body capable of transmitting light, a structural member used in a normal display device, or the like can be used.

The thickness of the back plate 105 may be, for example, 5 μm or more and 2000 μm or less, preferably 10 μm or more and 1000 μm or less, and more preferably 15 μm or more and 500 μm or less.

The plate-shaped body used for the back panel 105 may be composed of only one layer, may include two or more layers, and the plate-shaped body exemplified in the front panel 101 may be used.

Examples of constituent members used in a normal display device used for the back panel 105 include isolation films, touch sensor panels, organic EL display elements, and the like. Examples of the stacking order of the constituent components in the display device include: front surface plate/circular polarizing plate/isolation film, front surface plate/circular polarizing plate/organic EL display device, front surface plate/circular polarizing plate/touch sensor Sensor panel/organic EL display element, front panel/touch sensor panel/circular polarizer/organic EL display element, etc. The back panel 105 is preferably a touch sensor panel.

(Touch sensor panel) As the touch sensor panel, as long as it is a sensor that can detect the touched position, the detection method is not limited, and examples include resistive film method, electrostatic capacitance coupling method, photo sensor method, ultrasonic method, Touch sensor panels of electromagnetic induction coupling method and surface acoustic wave method. In terms of low cost, touch sensor panels of resistive film method and electrostatic capacitance coupling method can be preferably used.

An example of a touch sensor panel of a resistive film method includes a pair of substrates arranged facing each other, an insulating spacer sandwiched between the pair of substrates, and a resistive film provided on the inner front surface of each substrate Transparent conductive film, and touch position detection circuit. In an image display device provided with a resistive film type touch sensor panel, if the surface of the front panel is touched, the opposing resistive films are short-circuited, and current flows through the resistive film. The touch position detection circuit detects the voltage change at this time, thereby detecting the touched position.

An example of the touch sensor panel of the capacitive coupling method includes a substrate, a transparent electrode for position detection provided on the entire surface of the substrate, and a touch position detection circuit. In the image display device provided with the touch sensor panel of the electrostatic capacitance coupling method, if the surface of the front surface plate is touched, the transparent electrode is grounded via the electrostatic capacitance of the human body at the touched point. The touch position detection circuit detects the grounding of the transparent electrode, thereby detecting the touched position.

The thickness of the touch sensor panel may be, for example, 5 μm or more and 2000 μm or less, or may be 5 μm or more and 100 μm or less.

[Phase Difference Layer] The laminated body 100 may have one or more retardation layers between the polarizer layer 103 and the back plate 105. The retardation layer may be laminated on the first adhesive layer 102 and the second adhesive layer 104, or may be laminated on other layers via a layer other than these layers containing an adhesive or adhesive (hereinafter also referred to as an adhesive layer) (Including other retardation layers).

Examples of the retardation layer include positive A plates such as λ/4 plates and λ/2 plates, and positive C plates. The retardation layer may be, for example, a retardation film that can be formed from the thermoplastic resin film, or a layer formed by curing a polymerizable liquid crystal compound, that is, a layer containing a cured product of a polymerizable liquid crystal compound, and the latter is preferred. The thickness of the retardation film may be the same as the thickness of the thermoplastic resin film. The thickness of the retardation layer formed by curing the polymerizable liquid crystal compound is, for example, 0.1 μm or more and 10 μm or less, preferably 0.5 μm or more and 8 μm or less, and more preferably 1 μm or more and 6 μm or less.

The retardation layer formed by curing the polymerizable liquid crystal compound can be formed by applying a composition containing the polymerizable liquid crystal compound to a base film and curing it. An alignment layer may also be formed between the base film and the coating layer. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film. The retardation layer formed by curing the polymerizable liquid crystal compound may be assembled in the laminate 100 in a form having an alignment layer and/or a base film. The back plate 105 may also be a base film for coating the composition.

[Laminated layer] The bonding layer is a layer disposed between the first adhesive layer 102 and the second adhesive layer 104, and is a layer containing an adhesive or an adhesive. The adhesive constituting the bonding layer may be the same adhesive as exemplified for the adhesive composition constituting the first adhesive layer 102 and the second adhesive layer 104, or other adhesives, such as (meth)acrylic acid Adhesives, styrene-based adhesives, silicone-based adhesives, rubber-based adhesives, urethane-based adhesives, polyester-based adhesives, epoxy-based copolymer adhesives, etc.

As the adhesive that constitutes the bonding layer, for example, it can be formed by combining one or two or more of water-based adhesives, active energy ray curable adhesives, adhesives, and the like. Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution, an aqueous two-component urethane-based emulsion adhesive, and the like. The active energy ray-curable adhesive is an adhesive that is cured by irradiating active energy rays such as ultraviolet rays. Examples include those containing polymerizable compounds and photopolymerizable initiators, those containing photoreactive resins, and those containing adhesives. Resins and photoreactive crosslinkers, etc. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable acrylic monomers, and photocurable urethane monomers, and those derived from these monomers. Body oligomers, etc. Examples of the photopolymerization initiator include those containing active species such as neutral radicals, anionic radicals, and cationic radicals by irradiating active energy rays such as ultraviolet rays.

The thickness of the bonding layer may be, for example, 1 μm or more, preferably 1 μm or more and 25 μm or less, more preferably 2 μm or more and 15 μm or less, and still more preferably 2.5 μm or more and 5 μm or less.

A laminate 200 according to another embodiment of the present invention, as shown in FIG. 2, for example, may include a front surface plate 101, a first adhesive layer 102, a polarizer layer 103, a second adhesive layer 104, and a back plate 105, and more It includes a bonding layer 108, a first retardation layer 106, a bonding layer 109, and a second retardation layer 107.

[Method of manufacturing laminate] The laminated body 100 and the laminated body 200 can be manufactured by a method including the steps in which the layers constituting the laminated body 100 and the laminated body 200 are bonded to each other via an adhesive layer or further via an adhesive layer. When bonding layers to each other via an adhesive layer or an adhesive layer, in order to improve adhesion, it is preferable to perform surface activation treatment such as corona treatment on one or both sides of the bonding surface.

The polarizer layer 103 can be directly formed on a thermoplastic resin film or a base film. The thermoplastic resin film or base film may be assembled in the laminate 100 or the laminate 200, or it may be peeled from the polarizer layer 103 and not used as a laminate. The component parts.

＜Display device＞ A display device according to an embodiment of the present invention includes the above-mentioned laminated body 100 and the laminated body 200. The display device is not particularly limited, and examples thereof include image display devices such as organic EL display devices, inorganic EL display devices, liquid crystal display devices, and electroluminescence display devices. The display device may also have a touch panel function. The laminated body 100 and the laminated body 200 have improved durability by suppressing the generation of bubbles in the adhesive layer, and are therefore suitable for display devices that have flexibility such as bending or bending.

In the display device, the laminated body 100 and the laminated body 200 have the front surface plate facing outward (the side opposite to the display element side, that is, the visible side), and are arranged on the visible side of the display element included in the display device. The display device is preferably capable of bending the front surface plate 101 side of the laminated body 100 and the laminated body 200 to the outside.

The display device of the present invention can be used as mobile devices such as smart phones, input panels, televisions, digital photo frames, electronic billboards, measuring devices, meters, office equipment, medical equipment, computer equipment, etc. [Example]

Hereinafter, the present invention will be explained in more detail with examples, but the present invention is not limited by these examples. In the present embodiment, when the terms "%" and "parts" are used for description, these terms refer to mass% and mass parts as long as there is no special description.

[test methods] The measurement method and calculation method of each physical property value (weight average molecular weight, each physical property of the adhesive layer, etc.) used in this Example are as follows.

<Measurement of weight average molecular weight (Mw)> The weight average molecular weight (Mw) of (meth)acrylic polymer A is the number average molecular weight (Mn) in terms of polystyrene. Tetrahydrofuran is used in the mobile phase, and the following particle size sieve chromatography (size exclusion chromatography, SEC).

Specifically, the (meth)acrylic polymer A as the object to be measured is dissolved in tetrahydrofuran at a concentration of about 0.05% by mass, and 10 μL is injected into a size exclusion chromatograph (SEC) . The mobile phase flows at a flow rate of 1.0 mL/min. As the column, PLgel MIXED-B (manufactured by Polymer Laboratories) was used. The detector used an ultraviolet-visible light detector (UV-VIS detector) (trade name: Agilent GPC).

<The thickness of the layer> The measurement was performed using a contact-type film thickness measuring device ("MS-5C" manufactured by Nikon Co., Ltd.). Among them, the polarizer layer and the alignment film were measured using a laser microscope (“OLS3000” manufactured by Olympus Co., Ltd.).

<Repetitive strain application test> The strain repeated application test was performed by using a viscoelasticity measuring device (MCR-301, Anton Paar). The specific test method is as follows. That is, the adhesive sheet (adhesive sheet A11, adhesive sheet A12, etc.) on which the adhesive layer described later is formed is cut into a width of 20 mm × a length of 20 mm, peeled off the release film, and laminated 8 sheets to form a thickness of 200 μm Adhesive reference layer (first adhesive reference layer and second adhesive reference layer). Next, the adhesive reference layer is bonded to the glass plate. Furthermore, for the adhesive reference layer on the glass plate, in the state of being bonded to the measurement wafer in the device, under the conditions of a temperature of 25°C, a normal force (Free), and a frequency of 2 Hz, Repeatedly apply 0% and 1000% Strain (in "%") for 1000 seconds (therefore, repeatedly apply 0% and 1000% Strain to the adhesive sheet for 1000 seconds) , Thereby performing the repeated strain application test.

＜Shear creep value and shear creep rate＞ For the first adhesive reference layer and the second adhesive reference layer before performing the strain repeated application test and the first adhesive reference layer and the second adhesive reference layer after performing the strain repeated application test, the following are used respectively Method to obtain the shear creep value at 25℃ (unit is "%"). That is, it is determined by measuring the shear creep value at 25° C. using the viscoelasticity measuring device (MCR-301, Anton Paar). Specifically, for the adhesive reference layer on the glass plate before or after the repeated strain application test is performed, in the state where it is in contact with the measurement wafer in the device, the temperature is 25 Under the conditions of normal force (Normal force) 1 N and torque (Torque) 1200 μNm, 1200 seconds have elapsed at ℃ to obtain the shear creep value under the elapsed time.

Furthermore, each value obtained as the shear creep value before and after performing the repeated strain application test was divided by the thickness (200 μm) of the first adhesive reference layer or the second adhesive reference layer. With this, the first shear creep rate (R1A, unit is "%/μm") is calculated for the shear creep value per 1 μm thickness of the first adhesive reference layer after the repeated strain application test is performed. ), for the shear creep value per 1 μm thickness of the first adhesive reference layer before performing the strain repeated application test, that is, the second shear creep rate (R1B), for the second adhesive after performing the strain repeated application test The shear creep value per 1 μm thickness of the adhesive reference layer is the third shear creep rate (R2A), and the shear potential per 1 μm thickness of the second adhesive reference layer before the repeated strain application test is performed. The change value is the fourth first shear creep rate (R2B). Then, by subtracting the second shear creep rate from the first shear creep rate and the fourth shear creep rate from the third shear creep rate, the respective subtraction values are obtained as ΔR1 and ΔR2 .

＜Gel fraction of adhesive layer＞ The gel fraction of the adhesive layer (adhesive layer A11 and adhesive layer A12) was measured in accordance with the following (I) to (V). (I) An adhesive layer having an area of about 8 cm×about 8 cm is bonded to a metal mesh (the mass is set to Wm) including stainless steel (SUS) 304 of about 10 cm×about 10 cm. (II) Weigh the mass of the paste obtained in (I), set its mass as Ws, and then fold it 4 times with an adhesive layer, and then weigh it with a stapler (stapler) , And set its mass to Wb. (III) Put the net nailed by a stapler in the above (II) into a glass container, add 60 mL of ethyl acetate and soak, and store the glass container at room temperature for 3 days. (IV) The net of (III) is taken out of the glass container, dried at 120°C for 24 hours, and then weighed, and its mass is set to Wa. (V) Substitute the weighed mass into the gel fraction (mass%)=[{Wa-(Wb-Ws)-Wm}/(Ws-Wm)]×100 to calculate the adhesive layer的gel fraction.

[Manufacture of Adhesive Sheet] [1] Manufacturing of adhesive sheet A11 (1) Preparation of (meth)acrylic polymer A A mixed solution of 81.8 parts by mass of acetone, 98.6 parts by mass of butyl acrylate, 1.0 part by mass of 2-hydroxyethyl acrylate, and 0.4 part by mass of acrylic acid was charged into a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, and nitrogen was used The air in the container was replaced with no oxygen, and the internal temperature was increased to 55°C. After that, the total amount of the solution obtained by dissolving 0.14 parts by mass of azobisisobutyronitrile (polymerization initiator) in 10 parts by mass of acetone was added. One hour after the addition of the polymerization initiator, acetone was continuously added to the reaction vessel at an addition rate of 17.3 parts by mass/hour so that the concentration of the acrylic resin other than the monomer was 35% by mass, while the internal temperature The temperature was kept at 54°C to 56°C for 12 hours, and finally acetone was added to adjust the concentration of acrylic resin to 20% by mass. The weight average molecular weight Mw of the obtained acrylic resin in terms of polystyrene by GPC was 1,270,000. This is referred to as (meth)acrylic polymer A. (Meth) acrylic polymer A, the structural unit derived from the hydroxyl-containing unsaturated monomer, namely 2-hydroxyethyl acrylate, is 1% by mass, and is derived from the carboxyl-containing unsaturated monomer, namely acrylic acid The unit is 0.4% by mass.

(2) Preparation of adhesive composition A11 The (meth)acrylic polymer A obtained in the above step and the polyisocyanate as the thermal crosslinking agent B (manufactured by Tosoh Co., Ltd., product name " "Coronate L") and 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBM403") as the silane coupling agent C, mix, stir well, and use formaldehyde The base ethyl ketone was diluted to obtain a coating solution of the adhesive composition A11. Table 1 shows each formulation (solid content conversion value) of the adhesive composition A11 when the (meth)acrylic polymer is 100 parts by mass (solid content conversion value). In Table 1, the abbreviation "BA" means n-butyl acrylate, "2EHA" means 2-ethylhexyl acrylate, and "AA" means acrylic acid. The Tg (°C) of these BA, 2EHA, and AA was obtained by differential thermal analysis (DTA).

(3) Manufacturing of adhesive sheet A11 The coating solution of the adhesive composition A11 was applied to the release treatment surface of the first release film (manufactured by Lintec Corporation, product name "SP-PET752150") using a knife coater, thereby Form a coating. The coating was heat-treated at 90°C for 1 minute to form a coating layer. Then, the coating layer on the first release release film and the second release film (manufactured by Lintec Corporation, product name " SP-PET382120") was bonded and cured for 7 days under the conditions of 23°C and 50%RH to produce an adhesive sheet A11 having a 25 μm-thick adhesive layer formed using the adhesive composition A11, that is, including the first An adhesive sheet A11 composed of a release film/adhesive layer (thickness: 25 μm)/second release film. In this embodiment, the adhesive layer of the adhesive sheet A11 is also referred to as the adhesive layer A11.

[2] Manufacturing of adhesive sheet A12 (1) Preparation of (meth)acrylic polymer A The (meth)acrylic polymer A used in the production of the pressure-sensitive adhesive sheet A11 is prepared.

(2) Preparation of adhesive composition A12 With respect to 100 parts by mass of the (meth)acrylic polymer A, the blending amount of Coronate L as a thermal crosslinking agent was set as shown in Table 1. Otherwise, set as The preparation method of the adhesive composition A11 is the same as that of the adhesive composition A11, thereby obtaining a coating solution of the adhesive composition A12.

(3) Manufacturing of adhesive sheet A12 The coating solution using the adhesive composition A12 is set to be the same as the production process of the adhesive sheet A11, thereby producing the adhesive sheet A12. In this embodiment, the adhesive layer of the adhesive sheet A12 is also referred to as the adhesive layer A12.

Table 1 shows each formulation (solid content conversion value) of the adhesive composition A12 when the (meth)acrylic polymer is 100 parts by mass (solid content conversion value). Table 1 also shows the value of the gel fraction of the adhesive composition A11 and the adhesive composition A12 obtained by the above method.

[Table 1] (Meth) acrylic polymer A (parts by mass) Thermal crosslinking agent B SC agent C characteristic Single body composition (parts by mass) Molecular weight (Mw) Coronate L (parts by mass) KBM-403 (parts by mass) Gel fraction (mass%) BA 2HEA AA total Tg (℃) -54 -15 105 A11 98.6 1 0.4 100 1.27 million 0.3 0.5 66 A12 98.6 1 0.4 100 1.27 million 0.4 0.5 70

Furthermore, as commercially available adhesive sheets, OCA8146-02 and CEF3004 (both manufactured by 3M Corporation, USA) were prepared.

[3] Manufacturing of adhesive sheet B11 (1) Preparation of (meth)acrylic polymer B1 In order to reflux the nitrogen gas and easily adjust the temperature, a cooling device is installed in the reaction vessel. The single-weight mixture described in Table 2 was put into the reaction vessel. To remove oxygen, nitrogen was purged for 1 hour. After maintaining the temperature at 60°C and uniformly mixing the monomer mixture, the photopolymerization initiator described in Table 2 was added. Then, it stirred and irradiated ultraviolet-ray (10 mW) from a UV lamp, and manufactured the (meth)acrylic-type polymer B1.

(2) Preparation of adhesive composition B11 The (meth)acrylic polymer B1, the active energy ray polymerizable compound, and the content of the photopolymerization initiator were mixed so that the content of the photopolymerization initiator was the ratio described in Table 3, and the adhesive composition B11 was produced.

(3) Production of adhesive sheet B11 The adhesive composition B11 was applied to a release film subjected to a silicon release treatment so that the thickness was 25 μm. After the release film was further laminated on the coating film, ultraviolet rays (cumulative light quantity 400 mJ/cm ² , illuminance 1.8 mW/cm ² , UVV standard) were irradiated to produce an adhesive sheet B11. In this embodiment, the adhesive layer of the adhesive sheet B11 is also referred to as the adhesive layer B11.

[4] Manufacturing of adhesive sheet B21 (1) Preparation of (meth)acrylic polymer B2 In order to reflux the nitrogen gas and easily adjust the temperature, a cooling device is installed in the reaction vessel. The single-weight mixture described in Table 2 was put into the reaction vessel. To remove oxygen, nitrogen was purged for 1 hour. After maintaining the temperature at 60°C and uniformly mixing the monomer mixture, the photopolymerization initiator described in Table 2 was added. Then, it stirred and irradiated ultraviolet-ray (10 mW) from a UV lamp, and manufactured the (meth)acrylic-type polymer B2.

(2) Preparation of adhesive composition B21 The (meth)acrylic polymer B2, the active energy ray polymerizable compound, and the content of the photopolymerization initiator were mixed so that the content of the photopolymerization initiator was the ratio described in Table 3, and the adhesive composition B21 was produced.

(3) Production of adhesive sheet B21 The adhesive composition B21 was applied to a release film subjected to a silicon release treatment in a thickness of 25 μm. After the release film was further laminated on the coating film, ultraviolet rays were irradiated (cumulative light quantity 400 mJ/cm ² , illuminance 1.8 mW/cm ² , UVV standard) to produce an adhesive sheet B21. In this embodiment, the adhesive layer of the adhesive sheet B21 is also referred to as the adhesive layer B21.

[Table 2] (Meth) acrylic polymer Single body mixture Photopolymerization initiator LA 2-EHA 2-HEA 2-PHA C22A ODA I-651 B1 52 40 2.5 2 1.5 2 0.05 B2 50 40 4 2 - 4 0.05 In Table 2, the abbreviation "LA" means lauryl acrylate, "2-EHA" means 2-ethylhexyl acrylate, "2-HEA" means 2-hydroxyethyl acrylate, and "2-PHA" means acrylic -2 -Propyl heptyl acrylate, "C22A" means behenyl acrylate, and "ODA" means octyldecyl acrylate.

[table 3] (Meth) acrylic polymer Active energy ray polymerizable compound Photopolymerization initiator species Allocation amount species Allocation amount species Allocation amount B11 B1 100 IBOA 0.5 I-184 0.05 B21 B2 100 IBOA 1 I-184 0.05 The abbreviation "IBOA" in Table 3 means isobornyl acrylate.

For the adhesive sheet, an adhesive reference layer with a thickness of 200 μm was produced in accordance with the method described above, and the shear potential of each adhesive reference layer before and after the strain repeated application test was determined. Change value (%), and the difference in shear creep rate (%/μm), etc. The results are shown in Table 4. Table 4 also shows the shear creep rate (%/μm) of each adhesive reference layer before the repeated strain application test.

[Table 4] A11 A12 B11 B21 8146-02 CEF3004 Shear creep value B (%) before performing repeated strain application test 33 25 twenty four 20 32 105 Shear creep value A (%) after performing repeated strain application test 52 47 35 33 57 1080 The thickness of the adhesive reference layer C (μm) 200 200 200 200 200 200 Difference of shear creep rate (%/μm) (ΔR1, ΔR2) (AB)/C 0.095 0.11 0.055 0.065 0.125 4.875 Shear creep rate (%/μm) B/C before performing repeated strain application test 0.165 0.125 0.120 0.100 0.160 0.525

[Manufacturing of laminated body] [Front Panel (Window Film)] As the front surface plate, a polyimide film (thickness 50 μm) with a hard coat layer (thickness 10 μm) on one side was prepared.

[Polarizer layer] 1. Material preparation Prepare the following materials.

1) Triacetyl cellulose (TAC) film with a thickness of 25 μm 2) Alignment film formation composition <Polymer 1> Prepare polymer 1 which has a photoreactive group containing the following structural units.

A solution obtained by dissolving the polymer 1 in cyclopentanone at a concentration of 5% by mass was prepared as a composition for forming an alignment film [hereinafter also referred to as a composition (D-1)].

3) Composition for forming polarizer layer <Polymerizable liquid crystal compound> As the polymerizable liquid crystal compound, a polymerizable liquid crystal compound represented by formula (1-1) [hereinafter also referred to as compound (1-1)] and formula ( 1-2) The represented polymerizable liquid crystal compound [hereinafter also referred to as compound (1-2)].

Compound (1-1) and Compound (1-2) were obtained by Lub et al. (Lub et al.) "Recl. Trav. Chim. Pays-Bas", 115, 321-328 ( The method described in 1996) was synthesized.

<Dichroic dye> As a dichroic dye, the examples of Japanese Patent Laid-Open No. 2013-101328 represented by the following formulas (2-1a), (2-1b), and (2-3a) are prepared Azo dyes described in.

The composition for forming a polarizer layer [hereinafter also referred to as composition (A-1)] is prepared by combining 75 parts by mass of compound (1-1) and 25 parts by mass of compound (1-2) as two 2.5 parts by mass each of the azo dyes represented by the formula (2-1a), formula (2-1b), and formula (2-3a) of the chromatic dye, 2-dimethylamino group as a polymerization initiator -2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369, manufactured by BASF Japan) 6 parts by mass, and as a leveling agent 1.2 parts by mass of polyacrylate compound (BYK-361N, manufactured by BYK-Chemie) was mixed with 400 parts by mass of toluene as a solvent, and the resulting mixture was stirred at 80°C for 1 hour.

4) Composition for forming protective layer (OC layer) The composition for forming the protective layer (OC layer) [hereinafter also referred to as composition (E-1)] is made by mixing water: 100 parts by mass, polyvinyl alcohol resin powder (Kuraray) (stock), average Polymerization degree 18000, trade name: KL-318): 3 parts by mass, polyamide epoxy resin (crosslinking agent, manufactured by Sumika Chemtex (stock), trade name: SR650 (30)): 1.5 The mass parts are mixed and prepared.

2. Production method 1) The composition for forming an alignment film is applied to the TAC film side in the following manner. That is, first, corona treatment is performed once on the TAC film side. The conditions of corona treatment were set to output 0.3 kW and processing speed 3 m/min. After that, the composition (D-1) obtained as described above was coated on the TAC by a bar coating method, and heated and dried in a drying oven at 80° C. for 1 minute. The obtained dry film was subjected to a polarization UV irradiation treatment to form a first alignment film (AL1). Polarized UV treatment is to make light irradiated from the UV irradiation device (SPOT CURE SP-7; manufactured by Usio Electric Co., Ltd.) pass through the wire grid (UIS-27132##, manufactured by Ushio Electric Co., Ltd.) And it is performed under the condition that the cumulative light intensity measured at a wavelength of 365 nm is 100 mJ/cm ² . The thickness of the first alignment film (AL1) is 100 nm.

2) The composition for forming a polarizer layer is applied to the alignment film side in the following manner. That is, first, the composition (A-1) was coated on the first alignment film (AL1) by a bar coating method, heated and dried in a drying oven at 120° C. for 1 minute, and then cooled to room temperature. Using the UV irradiation device, ultraviolet rays were irradiated to the dry film at a cumulative light amount of 1200 mJ/cm ² (365 nm reference), thereby forming a polarizer layer (pol). The thickness of the obtained polarizer layer (pol) was measured by a laser microscope (OLS3000 manufactured by Olympus Co., Ltd.), and the result was 1.8 μm. In this way, a laminate including "TAC/AL1/pol" is obtained.

3) The composition for forming a protective layer (OC layer) is applied to the polarizer layer side as follows. That is, on the polarizer layer (pol) layer, the composition (E-1) was applied by a bar coating method, and then applied so that the thickness after drying was 1.0 μm, and dried at a temperature of 80°C for 3 minute. In this way, a laminate including "TAC film/cPL (AL1+pol+protective layer)" is obtained.

[Phase Difference Layer] 1. Material preparation Prepare the following materials.

1) PET film with a thickness of 100 μm 2) Composition for forming alignment film A solution obtained by dissolving the polymer 1 in cyclopentanone at a concentration of 5% by mass was prepared as a composition for forming an alignment film (composition (D-1)).

3) Composition for forming retardation layer The components shown below were mixed, and the resulting mixture was stirred at 80°C for 1 hour to obtain a composition (B-1).

Compound b-1 represented by the following formula: 80 parts by mass

Compound b-2 represented by the following formula: 20 parts by mass

Polymerization initiator (Irgacure 369, 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl) butan-1-one, BASF Japan) Made by the company): 6 parts by mass Leveling agent (BYK-361N, polyacrylate compound, manufactured by BYK-Chemie): 0.1 parts by mass Solvent (cyclopentanone): 400 parts by mass.

2. Production method 1) The composition for forming an alignment film is applied to a PET film in the following manner. That is, a polyethylene terephthalate film (PET) with a thickness of 100 μm was prepared as a base material, and the composition (D-1) was applied to the film by a bar coating method, and then placed in a drying oven at 80°C. Heat and dry for 1 minute. The obtained dry film is subjected to a polarization UV irradiation treatment to form a second alignment film (AL2). The polarized UV treatment was performed using the UV irradiation device described above, and the cumulative light amount measured at a wavelength of 365 nm was 100 mJ/cm ² . It is performed so that the polarization direction of the polarized light UV is 45° with respect to the absorption axis of the polarizer layer. In this way, a laminate including "base material (PET)/second alignment film (AL2)" is obtained.

2) The composition for forming a retardation layer is applied to the alignment film side of the PET film in the following manner. That is, on the second alignment film (AL2) of the laminate including the "base material (PET)/second alignment film (AL2)", the composition (B-1) is applied by the bar coating method, and the After heating and drying in a drying oven at 120°C for 1 minute, it was cooled to room temperature. The obtained dry film was irradiated with ultraviolet rays having a cumulative light intensity of 1000 mJ/cm ² (based on 365 nm) using the UV irradiation device to form a retardation layer. The thickness of the obtained retardation layer was measured by a laser microscope (OLS3000 manufactured by Olympus Co., Ltd.) and it was 2.0 μm. The retardation layer is a λ/4 plate (Quarter-Wave Plate (QWP)) that displays a λ/4 retardation value in the in-plane direction. In this way, a laminate including "base material (PET)/phase difference part (AL2+QWP)" is obtained.

[Share adhesive sheet] 1) Polymerization of acrylic resin The following components were reacted at 55°C while stirring in a nitrogen atmosphere, thereby obtaining an acrylic resin. Butyl acrylate: 70 parts by mass Methyl acrylate: 20 parts by mass Acrylic: 2.0 parts by mass Radical polymerization initiator (2,2'-azobisisobutyronitrile): 0.2 parts by mass.

2) Liquid adjustment of adhesive composition The following components are mixed to obtain an adhesive composition. Acrylic resin: 100 parts by mass Crosslinking agent ("Coronate L" manufactured by Tosoh Corporation): 1.0 parts by mass Silane coupling agent ("X-12-981" manufactured by Shin-Etsu Chemical Co., Ltd.): 0.5 parts by mass.

Ethyl acetate was added so that the total solid content concentration was 10% by mass, and the adhesive composition was liquid-adjusted.

3) Manufacturing of shared adhesive sheets Using an applicator, apply the adhesive composition prepared as above to a polyethylene terephthalate film (heavy release film, thickness 38 μm) mold release treatment surface to obtain a coating layer. The coating layer was dried at 100°C for 1 minute to obtain a film including an adhesive layer. Thereafter, another polyethylene terephthalate film (light barrier film, thickness 38 μm) subjected to mold release treatment was attached to the exposed surface of the adhesive layer. Thereafter, it was cured for 7 days under the conditions of a temperature of 23° C. and a relative humidity of 50% RH to obtain a common adhesive sheet having a layer structure of light isolation film/common adhesive layer/heavy isolation film.

[Back Panel] As the back plate, a PET film with a thickness of 100 μm was prepared.

[Example 1] The laminated body was manufactured in the order shown in FIG. 3(a)-FIG. 3(e). First, as shown in Figure 3(a), prepare the polarizer layer 410 [TAC film 301/cPL ((AL1+pol)302/OC layer 303)] and the common adhesive sheet 420 (light isolation film 304) /Common adhesive layer 305/Re-isolation film 306). The OC layer 303 side of the polarizer layer 410 and the surface of the common adhesive sheet 420 from which the light isolation film 304 was peeled were subjected to corona treatment (output 0.3 kW, processing speed 3 m/min), and then bonded, thereby The first laminate precursor 430 shown in (b) of FIG. 3 is obtained. Furthermore, as shown in (b) of FIG. 3, the retardation layer 440 [base material (PET) 308/phase difference part (AL2+QWP) 307] is prepared.

Next, corona treatment was performed on the side of the retardation portion 307 of the retardation layer 440 and the surface of the first laminate precursor 430 from which the heavy isolation film 306 was peeled (output 0.3 kW, processing speed 3 m/min), and then pasted In this way, the second laminate precursor 450 shown in (c) of FIG. 3 is obtained. After that, as shown in FIG. 3( c ), the adhesive sheet A11 is prepared as the adhesive sheet 460 (first release film 309/adhesive layer 310/second release film 311). The adhesive layer 310 of the adhesive sheet 460 corresponds to the second adhesive layer.

The surface of the second laminate precursor 450 from which the base material (PET) 308 was peeled off and the surface of the adhesive sheet 460 from which the first release film 309 was peeled were subjected to corona treatment (output 0.3 kW, processing speed 3 m/min), Then, bonding is performed, thereby obtaining the third laminate precursor 470 shown in (d) of FIG. 3. Furthermore, the adhesive sheet A12 was prepared as an adhesive sheet 490 (first release film 314/adhesive layer 315/second release film 316), and the surface from which the first release film 314 was peeled and the front surface plate 480 (poly The polyimide film 313/hard coat layer 312) is subjected to corona treatment (output 0.3 kW, processing speed 3 m/min) on the polyimide film 313 side, and then bonded to obtain Figure 3 (d) The fourth laminate precursor 500 is shown. The adhesive layer 315 of the adhesive sheet 490 corresponds to the first adhesive layer.

Next, corona treatment was applied to the surface of the fourth laminate precursor 500 from which the second release film 316 was peeled and the TAC 301 side of the third laminate precursor 470 (output 0.3 kW, processing speed 3 m/min), and then By bonding, the sixth laminate precursor 300 shown in FIG. 3(e) is obtained. Finally, the second release film 311 was peeled from the sixth laminate precursor 300, and corona treatment was performed on the peeled surface and one of the 100 μm thick PET film prepared as the back sheet (output 0.3 kW, processing speed 3 m/min), and then lamination was performed, thereby obtaining the laminate of Example 1. The laminate of Example 1 had a shape of 240 μm in thickness, 190 mm in length × 150 mm in width.

[Example 2 to Example 5, Comparative Example 1 to Comparative Example 2] The adhesive sheet having the adhesive layer shown in Table 5 was used instead of the adhesive sheet A11 and the adhesive sheet A12 used in Example 1, except that the same manufacturing method as the laminate of Example 1 was applied to manufacture and implement The laminates of Example 2 to Example 5 and Comparative Example 1 to Comparative Example 2.

Regarding the laminates of Examples 1 to 5 and Comparative Examples 1 to 2, the types of adhesive compositions used to form the first adhesive layer and the second adhesive layer are collectively shown in Table 5. Examples 1 to 5 satisfy the relationship of ΔR1>ΔR2, and Comparative Examples 1 to 2 have the relationship of ΔR1≦ΔR2.

[table 5] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative example 1 Comparative example 2 First adhesive layer A12 8146-02 8146-02 B21 A11 A11 8146-02 Second adhesive layer A11 A12 A11 B11 B11 A12 CEF3004

Furthermore, the laminates of Examples 1 to 5 and Comparative Examples 1 to 2 were subjected to a bending durability test and a surface hardness test by the method described later. The results are shown in Table 6.

＜Bending durability test (mandrel test)＞ A super cutter was used to cut a test piece with a length of 100 mm and a width of 10 mm from the laminate of each example and each comparative example. For this test piece, a bending resistance tester (cylinder method mandrel method) manufactured by TP Giken Co., Ltd. was used to wind the test piece around the cylinder with the back plate of the test piece (laminated body) as the inside. Around the shape of the mandrel (mandrel), a bending durability test (mandrel test) was performed in which the test piece was bent in the longitudinal direction at a temperature of 25°C. In this way, the minimum diameter of the mandrel that does not generate bubbles in the adhesive layer of the test piece (layered body) was determined, and the classification was performed based on the following criteria. In the bending durability test, the smaller the value of the minimum diameter, the better the bending durability of the adhesive layer can be evaluated. A: Air bubbles are generated in the adhesive layer when wound around a mandrel below Φ10 mm B: Air bubbles are generated in the adhesive layer when wound on a mandrel over Φ10 mm and less than Φ15 mm C: Air bubbles are generated in the adhesive layer when wound on a mandrel that exceeds Φ15 mm and Φ20 mm or less D: Air bubbles are generated in the adhesive layer when wound on a mandrel over Φ20 mm.

＜Surface hardness test＞ Using a pencil hardness tester (PHT, manufactured by SUKBO SCIENCE) on the surface of the back plate of the laminate of each example and each comparative example, a load of 100 g was applied at a temperature of 25°C. A pencil (manufactured by Mitsubishi Pencil Co., Ltd., with a core hardness of 6B) in the same state, with a trace of recesses formed on the surface. In this case, the time until the trace of the recessed portion disappeared was determined, and the classification was performed based on the following criteria to evaluate the surface hardness of the laminate of each Example and each Comparative Example. In this surface hardness test, the shorter the time until the traces of the recesses disappear, the better the surface hardness can be evaluated. A: The dent marks disappeared in less than 30 minutes B: More than 30 minutes and less than 60 minutes, the dent marks disappear C: More than 60 minutes and less than 90 minutes, the dent marks disappear D: Even after 90 minutes, the dent marks did not disappear.

[Table 6] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative example 1 Comparative example 2 Mandrel test (25℃) A A B A A D D Surface hardness test (25℃) A B A A A B D

According to the foregoing, Examples 1 to 5 satisfy the relationship of ΔR1>ΔR2, and are superior in the evaluation of bending durability and surface hardness compared to Comparative Examples 1 to 2 in the relationship of ΔR1≦ΔR2.

100, 200: layered body 101, 480: front surface plate 102: The first adhesive layer 103: Polarizer layer 104: second adhesive layer 105: back panel 106: first phase difference layer 107: second retardation layer 108, 109: Laminated layer 300: Precursor of the sixth laminate 301: TAC film 302:AL1+pol 303: OC layer 304: light isolation film 305: Shared adhesive layer 306: Heavy Isolation Film 307: Phase difference part 308: Substrate (PET) 309, 314: the first release film 310, 315: Adhesive layer 311, 316: second release film 312: Hard coating 313: Polyimide film 410: Polarizer layer 420: shared adhesive sheet 430: Precursor of the first laminate 440: retardation layer 450: Precursor of the second laminate 460, 490: Adhesive sheet 470: Precursor of the third laminate 500: precursor of the fourth laminate

Fig. 1 is a schematic cross-sectional view showing an example of the laminate of the present invention. Fig. 2 is a schematic cross-sectional view showing another example of the laminate of the present invention. 3(a) to 3(e) are cross-sectional views schematically showing the manufacturing method of the laminate of the present invention.

100: layered body

101: front panel

102: The first adhesive layer

103: Polarizer layer

104: second adhesive layer

105: back panel

Claims (7)

A layered body, in turn, includes: a front surface plate; a first adhesive layer formed by using a first adhesive composition; a polarizer layer; a second adhesive layer formed by using a second adhesive composition; And the back panel, In the same manner as the thickness of the first adhesive reference layer and the thickness of the second adhesive reference layer, the first adhesive composition is used to form the first adhesive reference layer and the second adhesive composition is used to form In the case of the second adhesive reference layer, the first adhesive reference layer and the second adhesive reference layer satisfy the relationship of the following formula (1): ΔR1>ΔR2 (1) [In formula (1), ΔR1 represents the value obtained by subtracting R1B from R1A, ΔR2 represents the value obtained by subtracting R2B from R2A, The R1A represents the shear creep value per 1 μm thickness at 25° C., which is the first shear creep rate (%/μm), calculated for the first adhesive reference layer after performing the strain repeated application test , The R1B represents the shear creep value per 1 μm thickness at 25°C calculated for the first adhesive reference layer before performing the strain repeated application test, that is, the second shear creep rate (%/μm) , The R2A represents the third shear creep rate (%/μm), which is the shear creep value per 1 μm thickness at 25°C, calculated for the second adhesive reference layer after the strain repeated application test , The R2B represents the fourth shear creep rate (%/μm), which is the shear creep value per 1 μm thickness at 25°C, calculated for the second adhesive reference layer before performing the repeated strain application test ]. The layered body according to claim 1, wherein the fourth shear creep rate (%/μm) is 0.1 or more and 0.2 or less. The laminate according to claim 1 or claim 2, wherein the thickness of at least one of the first adhesive layer and the second adhesive layer is 20 μm or more and 50 μm or less. The laminated body according to any one of claims 1 to 3, wherein there is one or more phase difference layers between the polarizer layer and the back plate. The laminated body according to any one of claim 1 to claim 4, wherein the back panel is a touch sensor panel. A display device comprising the laminate according to any one of claim 1 to claim 5. The display device according to claim 6, which can bend the front surface plate side outward.

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