KR102393475B1 - Optical laminate and display device - Google Patents

Abstract

The present invention provides an optical laminate having improved adhesion between an adhesive layer and an adherend, and a display device including the optical laminate. A front plate, a first pressure-sensitive adhesive layer, a polarizing plate, a second pressure-sensitive adhesive layer, and a rear plate are provided in this order, wherein the first pressure-sensitive adhesive layer is a component having a weight average molecular weight of 100,000 or less among components eluted by immersion in ethyl acetate An optical laminate having a ratio of 10% by mass or more and 30% by mass or less is provided. The said 2nd adhesive layer, Preferably, among the components immersed in ethyl acetate and eluted, the ratio of the component whose weight average molecular weight is 100,000 or less is 10 mass % or more and 30 mass % or less.

Description

Optical laminate and display device

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

Japanese Patent Application Laid-Open No. 2018-027995 (Patent Document 1) describes a flexible image display device provided with an adhesive layer excellent in stress relaxation characteristics.

Patent Document 1: Japanese Patent Laid-Open No. 2018-027995

The optical laminated body in which the some layer was laminated|stacked through the adhesive layer had the problem that a bubble easily generate|occur|produced between an adhesive layer and the layer of a to-be-adhered body.

An object of this invention is to provide the optical laminated body which the adhesive force between an adhesive layer and to-be-adhered body improved, and the display device containing the said optical laminated body.

This invention provides the optical laminated body and display apparatus illustrated below.

[1] A front plate, a first adhesive layer, a polarizing plate, a second adhesive layer, and a back plate are provided in this order,

The said 1st adhesive layer is an optical laminated body whose ratio of the component whose weight average molecular weight is 100,000 or less among the components immersed in ethyl acetate and eluted is 10 mass % or more and 30 mass % or less.

[2] 　 The optical laminate according to [1], wherein the ratio of the component having a weight average molecular weight of 100,000 or less among the components eluted by immersion in ethyl acetate in the second pressure-sensitive adhesive layer is 10% by mass or more and 30% by mass or less.

[3] 　The glass transition temperature of the component eluted by immersing the first pressure-sensitive adhesive layer in ethyl acetate and the glass transition temperature of the component eluted by immersing the second pressure-sensitive adhesive layer in ethyl acetate are, respectively, -70 ° C. or more and -40 The optical laminate according to [1] or [2], which is °C or less.

[4] 　 When the gel fraction of the first pressure-sensitive adhesive layer is R1 (%) and the gel fraction of the second pressure-sensitive adhesive layer is R2 (%), the following relational expression:

R1<R2

The optical laminate according to any one of [1] to [3], which satisfies

[5] The optical laminate according to any one of [1] to [4], wherein the gel fraction of the first pressure-sensitive adhesive layer is 60% or more and 95% or less.

[6] The optical laminate according to any one of [1] to [5], wherein the gel fraction of the second pressure-sensitive adhesive layer is 60% or more and 95% or less.

[7] A display device comprising the optical laminate according to any one of [1] to [6].

[8] 　 The display device according to [7], wherein the front plate side can be bent inside.

According to the present invention, it is possible to provide an optical laminate having improved adhesion between the pressure-sensitive adhesive layer and the adherend, and a display device including the optical laminate.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows an example of the optical laminated body which concerns on this invention.
It is a schematic diagram explaining the method of calculating|requiring the ratio of the component whose weight average molecular weight is 100,000 or less among the components immersed and eluted by immersing an adhesive layer in ethyl acetate.
3 is a schematic diagram illustrating a static bending durability test.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of the optical laminated body which concerns on this invention is described referring drawings, this invention is not limited to the following embodiment. In all the drawings below, in order to make each component easy to understand, the scale is appropriately adjusted and shown, and the scale of each component shown in a figure and the scale of the actual component do not necessarily correspond.

<Optical laminated body>

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the optical laminated body by one Embodiment of this invention. The optical laminated body 100 shown in FIG. 1 is equipped with the front plate 101, the 1st adhesive layer 102, the polarizing plate 103, the 2nd adhesive layer 104, and the back plate 105 in this order. do. Hereinafter, the first pressure-sensitive adhesive layer 102 and the second pressure-sensitive adhesive layer 104 may be collectively referred to as a pressure-sensitive adhesive layer.

The thickness of the optical laminate 100 is not particularly limited because it varies depending on the functions required for the optical laminate, the use of the optical laminate, and the like, but is, for example, 50 µm or more and 4000 µm or less, preferably 70 µm or more and 2000 It is micrometer or less, More preferably, they are 100 micrometers or more and 1000 micrometers or less.

The planar view shape of the optical laminate 100 may be, for example, a square shape, Preferably it is a rectangular shape which has a long side and a short side, More preferably, it is a rectangle. When the shape of the surface direction of the optical laminated body 100 is a rectangle, the length of the long side may be 10 mm or more and 1400 mm or less, for example, Preferably they are 50 mm or more and 600 mm or less. The length of the short side is, 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. As for each layer which comprises the optical laminated body 100, the edge part may be R-processed, the edge part may be notched, or the punching process may be carried out.

The optical laminate 100 can be used, for example, in a display device or the like. A display apparatus is not specifically limited, For example, an organic electroluminescent (organic EL) display apparatus, an inorganic electroluminescent (inorganic EL) display apparatus, a liquid crystal display apparatus, an electroluminescent display apparatus, etc. are mentioned. The optical laminate 100 is particularly suitable for a display device that can be bent.

[Ratio of low molecular weight components]

The optical laminate 100 is a suspension prepared by immersing the first pressure-sensitive adhesive layer 102 in ethyl acetate, and among the components eluted from the first pressure-sensitive adhesive layer 102, a component having a weight average molecular weight of 100,000 or less (this specification) ) is 10 mass% or more and 30 mass% or less, and preferably 15 mass% or more and 25 mass% or less.

In the optical laminate 100, in the suspension prepared by immersing the second pressure-sensitive adhesive layer 104 in ethyl acetate, among the components eluted from the second pressure-sensitive adhesive layer 104, the ratio of the low molecular weight component is preferably 10% by mass. It is more than 30 mass %, More preferably, it is 15 mass % or more and 25 mass % or less.

Suspension is the liquid which melt|dissolved the adhesive layer in ethyl acetate which is a solvent, and filtered it with the mesh size 200. The suspension contains components eluted from the pressure-sensitive adhesive layer, such as polymers and monomers of molecular size that can pass through a mesh size of 200. The eluted component may include a component dissolved, dispersed or precipitated in ethyl acetate. The distribution of the weight average molecular weight of the eluted component can be determined by, for example, size exclusion chromatography. The ratio of the low-molecular-weight component having a weight average molecular weight of 100,000 or less can be obtained according to the method described in the column of Examples to be described later.

In the above suspension, when the ratio of the low molecular weight component to the eluted component is 10% by mass or more and 30% by mass or less, the optical laminate 100 has excellent adhesion between the pressure-sensitive adhesive layer and the adherend. In such an optical laminated body 100, it is hard to generate|occur|produce a bubble between an adhesive layer and the layer which contact|connects an adhesive layer. Generation|occurrence|production of a bubble can be judged by observation under an optical microscope.

The ratio of the low-molecular-weight component to the eluted component is: the type and compounding amount of the monomer constituting the base polymer in the pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer; the type and amount of polymerization initiator, crosslinking agent and other additives; By adjusting an active energy ray, heat, other factors which change the degree of crosslinking, it can be set as a desired numerical range.

[Glass transition temperature of the eluted component]

In the optical laminate 100, the glass transition temperature (Tg) of the component eluted by immersing the first pressure-sensitive adhesive layer 102 in ethyl acetate, and the component eluted by immersing the second pressure-sensitive adhesive layer 104 in ethyl acetate. It is preferable that a glass transition temperature is -70 degreeC or more and -40 degrees C or less, respectively. In the suspension prepared by immersing the pressure-sensitive adhesive layer in ethyl acetate, when the glass transition temperature of the eluted component is -40° C. or less, the flexibility of the pressure-sensitive adhesive layer is good, so that the optical laminate 100 can be easily bent. In the suspension, when the glass transition temperature of the eluted component is lower than -70°C, the cohesive force of the pressure-sensitive adhesive layer may be lowered, and the adhesion force under durable conditions may decrease. The glass transition temperature of the eluted component can be measured according to the method described in the column of Examples to be described later.

The optical laminate is usually in a bent state (hereinafter referred to as "static bending". A "static bending" is a form more severe than dynamic bending that repeats bending.) A layer in contact with the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer It is easy to generate|occur|produce a bubble between or in an adhesive layer. As a result of the research by the present inventors, among the components eluted by immersing the first pressure-sensitive adhesive layer 102 in ethyl acetate, the ratio of the component having a weight average molecular weight of 100,000 or less is 10% by mass or more and 30% by mass or less of the optical laminate (100 ) found that generation of air bubbles between the pressure-sensitive adhesive layer and the layer in contact with the pressure-sensitive adhesive layer and in the pressure-sensitive adhesive layer was suppressed (hereinafter, also referred to as having excellent “static bending durability”) even when static bending. Further, among the components eluted by immersing the second pressure-sensitive adhesive layer 104 in ethyl acetate, the optical laminate 100 in which the proportion of components having a weight average molecular weight of 100,000 or less is 10% by mass or more and 30% by mass or less, more excellent static bending I found something with the durability. In addition, the glass transition temperature of the component eluted by immersing the first adhesive layer 102 in ethyl acetate and the glass transition temperature of the component eluted by immersing the second adhesive layer 104 in ethyl acetate are -70° C. or higher, respectively It was discovered that the optical laminated body 100 which is -40 degrees C or less has more outstanding static bending durability. Here, when it statically bends, generation|occurrence|production of a bubble is suppressed means that a bubble does not generate|occur|produce within 12 hours, even if it uses an optical laminated body to the static bending durability test mentioned later. At this time, generation|occurrence|production of the float or peeling between an adhesive layer and the layer which contact|connects an adhesive layer is also suppressed.

In the suspension of the pressure-sensitive adhesive layer, when the ratio of the low molecular weight component to the eluted component is less than 10% by mass, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer is excessively polymerized or crosslinked, and when the optical laminate is bent, the pressure-sensitive adhesive layer It is estimated that a crack becomes easy to generate|occur|produce. When the ratio of the low molecular weight component to the eluted component exceeds 30 mass % in the suspension of the pressure-sensitive adhesive layer, the cohesive force of the pressure-sensitive adhesive composition is insufficient, and when the optical laminate is bent, it is estimated that the cohesive failure of the pressure-sensitive adhesive layer is likely to occur do.

In the present specification, the bending includes a bending form in which a curved surface is formed in the bending portion, and the bending radius of the bent inner surface is not particularly limited. Bending also includes refraction in which the refraction angle of the inner surface is greater than 0 degrees and less than 180 degrees, and folding in which the bending radius of the inner surface is close to zero, or the refraction angle of the inner surface is 0 degrees.

The glass transition temperature of the eluted component is determined by the type and compounding amount of the monomer constituting the base polymer in the pressure-sensitive adhesive composition; the type and amount of polymerization initiator, crosslinking agent and other additives; By adjusting an active energy ray, heat, other factors which change the degree of crosslinking, it can be set as a desired numerical range. In order to set the glass transition temperature of the eluted component to -40°C or less, the base polymer in the pressure-sensitive adhesive composition has a glass transition temperature of -40°C or less, preferably -45°C or less, more preferably -50°C or less acrylic acid. It is preferable to have an ester monomer as the structural unit. Examples of such a monomer include n-butyl acrylate (Tg: -55°C), n-octyl acrylate (Tg: -65°C), isooctyl acrylate (Tg: -58°C), and 2-ethylhexyl acrylate (Tg). : -70°C), isononyl acrylate (Tg: -58°C), isodecyl acrylate (Tg: -60°C), isodecyl methacrylate (Tg: -41°C), n-lauryl methacrylate (Tg : -65 degreeC), acrylic acid tridecyl (Tg: -55 degreeC), and methacrylic acid tridecyl (Tg:-40 degreeC) are mentioned, n-butyl acrylate and 2-ethylhexyl acrylate are preferable. These monomers may be used independently and may be used in combination of 2 or more type.

The base polymer in the pressure-sensitive adhesive composition contains preferably 80 mass% or more, more preferably 85 mass% or more, still more preferably 95 mass% or more of structural units derived from a monomer having a glass transition temperature of -40°C or less. In addition, the base polymer in the pressure-sensitive adhesive composition contains preferably 99.9 mass% or less, more preferably 99.5 mass% or less, still more preferably 99 mass% or less of structural units derived from a monomer having a glass transition temperature of -40°C or less. do. When content of the structural unit derived from the monomer whose glass transition temperature is -40 degrees C or less is such a range, the glass transition temperature of the eluted component easily falls within the above-mentioned range.

In order to easily set the glass transition temperature of the eluted component in the above range, the base polymer in the pressure-sensitive adhesive composition preferably contains as few structural units as possible derived from a monomer having a glass transition temperature exceeding 0 ° C. It is preferable to contain 15 mass % or less as an upper limit of the structural unit derived from such a monomer, It is more preferable to contain 10 mass % or less, It is more preferable to contain 5 mass % or less.

[Front panel]

The material and thickness of the front plate 101 are not limited as long as it is a plate-shaped body which can transmit light. The front plate may be comprised only by one layer, and may be comprised by two or more layers. As the front plate 101, a resin plate-shaped object (for example, a resin plate, a resin sheet, a resin film, etc.) and a glass plate-shaped object (for example, a glass plate, a glass film, etc.) are mentioned. The front plate 101 may constitute the outermost surface of the display device. The front plate 101 may be a laminate of a plate-like body made of resin and a plate-like body made of glass.

The thickness of the front plate 101 may be, for example, 30 µm or more and 500 µm or less, preferably 40 µm or more and 200 µm or less, more preferably 50 µm or more and 100 µm or less, and 70 µm or less. In the present invention, the thickness of each layer constituting the optical laminate 100 can be measured according to the thickness measurement method described in Examples to be described later.

When the front 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 resin plate-like body include triacetyl cellulose, acetyl cellulose butyrate, ethylene-vinyl acetate copolymer, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, polyester, polystyrene, polyamide. , polyetherimide, poly(meth)acrylic, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone and polymers such as polyetheretherketone, polyethersulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyamideimide. These polymer|macromolecule can be used individually or in mixture of 2 or more types. From the viewpoint of improving strength and transparency, the resin-made plate is preferably a resin film formed of a polymer such as polyimide, polyamide, or polyamideimide.

From the viewpoint of increasing hardness, the front plate 101 may be a resin film provided with a hard coat layer. The hard-coat layer may be formed in one surface of a resin film, and may be formed in both surfaces. By providing a hard-coat layer, hardness and scratch resistance can be improved. The hard coat layer is, for example, a cured layer of an ultraviolet curable resin. Examples of the ultraviolet curable resin include acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins. The hard-coat layer may contain the additive in order to improve hardness. The additive is not particularly limited, and examples thereof include inorganic fine particles, organic fine particles, and mixtures thereof. When having a hard-coat layer on both surfaces of a resin film, the composition and thickness of each hard-coat layer may mutually be mutually same, and may differ from each other.

When the front plate 101 is a glass plate, as the glass plate, tempered glass for a display is preferably used. The thickness of a glass plate may be 10 micrometers or more and 1000 micrometers or less, 20 micrometers or more and 500 micrometers or less may be sufficient, and 100 micrometers or less may be sufficient, for example. By using a glass plate, the front plate 101 which has excellent mechanical strength and surface hardness can be comprised.

When the optical laminate 100 is used in a display device, the front plate 101 not only has a function (function as a window film) to protect the front surface (screen) of the display device, but also functions as a touch sensor, blue light What has a cut function, a viewing angle adjustment function, etc. may be sufficient.

[First Adhesive Layer]

The 1st adhesive layer 102 is interposed between the front plate 101 and the polarizing plate 103, and these are bonded together. One layer may be sufficient as the 1st adhesive layer 102, Although what consists of two or more layers may be sufficient, Preferably it is one layer.

The first pressure-sensitive adhesive layer 102 may be composed of a pressure-sensitive adhesive composition containing (meth)acrylic resin, rubber-based resin, urethane-based resin, ester-based resin, silicone-based resin, and polyvinyl ether-based resin as a main component (base polymer). As the pressure-sensitive adhesive composition constituting the first pressure-sensitive adhesive layer 102 , a pressure-sensitive adhesive composition containing, as a base polymer, a (meth)acrylic resin excellent in transparency, weather resistance, heat resistance, and the like is suitable. An active energy ray hardening type or a thermosetting type may be sufficient as an adhesive composition.

As the (meth)acrylic resin used in the pressure-sensitive adhesive composition, (meth)acrylic acid ester, such as butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. Or the polymer or copolymer which uses 2 or more types as a monomer is used suitably. It is preferable to copolymerize a polar monomer with a base polymer. As the polar monomer, (meth)acrylic acid compound, (meth)acrylic acid 2-hydroxypropyl compound, (meth)acrylic acid hydroxyethyl compound, (meth)acrylamide compound, N,N-dimethyl aminoethyl (meth)acrylate Monomers, such as a compound and a glycidyl (meth)acrylate compound, which have a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc. are mentioned.

Although the adhesive composition may contain only the said base polymer, normally, it further contains a crosslinking agent. Examples of the crosslinking agent include a metal ion having a divalent or higher valence, a metal ion that forms a carboxylate metal salt between a carboxyl group, a polyamine compound that forms an amide bond between a carboxyl group, and a poly that forms an ester bond between a carboxyl group The polyisocyanate compound which forms an amide bond between an epoxy compound or a polyol, and a carboxyl group is illustrated. The crosslinking agent is preferably a polyisocyanate compound.

The active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by irradiation with active energy rays such as ultraviolet rays or electron beams, has adhesiveness even before irradiation with active energy rays, and can adhere to an adherend such as a film, and is cured by irradiation with active energy rays It has the property of being able to adjust the adhesion force. It is preferable that an active energy ray hardening-type adhesive composition is an ultraviolet curable type. In addition to a base polymer and a crosslinking agent, an active energy ray hardening-type adhesive composition contains an active energy ray polymeric compound further. You may contain a photoinitiator, a photosensitizer, etc. as needed.

As an active energy ray polymeric compound, For example, the (meth)acrylate monomer which has at least 1 piece(s) acryloyloxy group in a molecule|numerator; (meth)acrylic compounds such as (meth)acryloyloxy group-containing compounds such as (meth)acrylate oligomers obtained by reacting two or more functional group-containing compounds and having at least two (meth)acryloyloxy groups in the molecule and compounds having at least two benzoylphenylmethacryloyl groups in the molecule. The pressure-sensitive adhesive composition may contain 0.1 parts by mass or more of the active energy ray polymerizable compound with respect to 100 parts by mass of the solid content of the pressure-sensitive adhesive composition, and may contain 10 parts by mass or less, 5 parts by mass or less, or 2 parts by mass or less.

A benzoylphenyl methacryloyl group means group represented by the following structures. * indicates a bond. The number of benzoylphenylmethacryloyl groups that the active energy ray-polymerizable compound has in a molecule may be 5 or less, and may be 4 or less.

[Tue 1]

As a compound which has at least two benzoylphenylmethacryloyl groups in a molecule|numerator, the following compound is mentioned, for example.

[Tuesday 2]

As a photoinitiator, benzophenone, benzyl dimethyl ketal, 1-hydroxy cyclohexyl ketone etc. are mentioned, for example. A photoinitiator may contain 1 type or 2 or more types. When an adhesive composition contains a photoinitiator, 0.01 mass part or more and 3.0 mass parts or less may be sufficient as the total content, for example with respect to 100 mass parts of solid content of an adhesive composition.

The pressure-sensitive adhesive composition includes fine particles for imparting light scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than the base polymer, tackifiers, fillers (metal powders and other inorganic powders, etc.), antioxidants, It may contain additives such as ultraviolet absorbers, dyes, pigments, colorants, defoamers, corrosion inhibitors, and photoinitiators.

The first pressure-sensitive adhesive layer 102 can be formed by applying the organic solvent diluent of the pressure-sensitive adhesive composition on a substrate and drying it. The first pressure-sensitive adhesive layer 102 may be formed using a pressure-sensitive adhesive sheet formed using the pressure-sensitive adhesive composition. When an active energy ray hardening-type adhesive composition is used, it can be set as the adhesive layer which has a desired degree of hardening by irradiating an active energy ray to the formed adhesive layer.

Although the thickness of the 1st adhesive layer 102 is not specifically limited, For example, it is preferable that they are 1 micrometer or more and 100 micrometers or less, It is more preferable that they are 3 micrometers or more and 50 micrometers or less, 20 micrometers or more may be sufficient.

From the viewpoint of improving the cohesive force of the first pressure-sensitive adhesive layer 102, the gel fraction of the first pressure-sensitive adhesive layer 102 is preferably 60% or more, more preferably 70% or more, and still more preferably 75%. or more, preferably 95% or less, more preferably 90% or less, still more preferably 85% or less. The gel fraction is measured according to the method described in Examples below. The gel fraction can be adjusted by changing the type and content of the monomer constituting the base polymer in the pressure-sensitive adhesive composition, the additive, the degree of crosslinking, and the like.

From the viewpoint of improving the cohesive force of the first pressure-sensitive adhesive layer 102, when the first pressure-sensitive adhesive layer 102 is used as a reference pressure-sensitive adhesive layer having a thickness of 150 μm, the shear modulus at a temperature of 25° C. is preferably 0.01 MPa or more. and more preferably 0.02 MPa or more, preferably 0.50 MPa or less, and more preferably 0.10 MPa or less. When the shear modulus of elasticity of the first pressure-sensitive adhesive layer 102 is within this range, the optical laminate 100 is less likely to cause cohesive failure even if bent, and bubbles are less likely to occur. A shear modulus can be adjusted by changing the kind and content of the monomer which comprises the base polymer in an adhesive composition, an additive, a crosslinking degree, etc. A shear modulus can be measured by the method as described in the Example mentioned later.

[Polarizer]

The polarizing plate 103 may be, for example, a linear polarizing plate, a circularly polarizing plate, an elliptically polarizing plate, or the like. Hereinafter, the circularly polarizing plate and the elliptically polarizing plate are collectively referred to as simply a circularly polarizing plate. The circularly polarizing plate includes a linearly polarizing plate and a retardation layer. Since the circularly polarizing plate can absorb the external light reflected in the image display apparatus, it can give the optical laminated body 100 a function as an antireflection film.

The thickness of the polarizing plate 103 may be 5 micrometers or more normally, 20 micrometers or more may be sufficient as it, 25 micrometers or more may be sufficient, and 30 micrometers or more may be sufficient as it. Moreover, it is preferable that it is 80 micrometers or less, and, as for the thickness of the polarizing plate 103, it is more preferable that it is 60 micrometers or less.

(linear polarizer)

The linear polarizing plate has a function of selectively transmitting linearly polarized light in one direction, which consists of light rays that are non-polarized light such as natural light. A linear polarizing plate includes a stretched film or stretched layer to which a dichroic dye is adsorbed, a cured product of a polymerizable liquid crystal compound, and a dichroic dye, and the dichroic dye is dispersed in the cured product of the polymerizable liquid crystal compound and oriented liquid crystal A layer etc. can be provided as a polarizer layer. The dichroic dye refers to a dye having a property in which the absorbance in the long-axis direction of the molecule differs from the absorbance in the short-axis direction. The linear polarizing plate using the liquid crystal layer as a polarizer layer is preferable since there is no restriction|limiting in a bending direction compared with the stretched film or stretched layer which made the dichroic dye adsorb|suck.

(Stretched film or polarizer layer which is a stretched layer to which a dichroic dye is adsorbed)

The polarizer layer, which is a stretched film to which a dichroic dye is adsorbed, is usually a step of uniaxially stretching a polyvinyl alcohol-based resin film, and dyeing a polyvinyl alcohol-based resin film with a dichroic dye such as iodine, thereby converting the dichroic dye to It can manufacture through the process of making it adsorb|suck, the process of treating the polyvinyl alcohol-type resin film to which the dichroic dye has adsorbed with the aqueous boric acid solution, and the process of washing with water after the process with the aqueous boric acid solution.

The thickness of a polarizer layer is 30 micrometers or less normally, Preferably it is 18 micrometers or less, More preferably, it is 15 micrometers or less. Making the thickness of the polarizer layer thin is advantageous for thinning the polarizing plate 103 . The thickness of a polarizer layer may be 1 micrometer or more normally, for example, 5 micrometers or more may be sufficient.

Polyvinyl alcohol-type resin is obtained by saponifying polyvinyl acetate-type resin. As polyvinyl acetate-type resin, the copolymer of vinyl acetate and other monomer copolymerizable to this other than polyvinyl acetate which is a homopolymer of vinyl acetate is used. Examples of the other monomer copolymerizable with vinyl acetate include an unsaturated carboxylic acid-based compound, an olefin-based compound, a vinyl ether-based compound, an unsaturated sulfone-based compound, and a (meth)acrylamide-based compound having an ammonium group.

The saponification degree of polyvinyl alcohol-type resin is about 85 mol% or more and 100 mol% or less normally, Preferably it is 98 mol% or more. The polyvinyl alcohol-type resin may be modified|denatured, and polyvinyl formal, polyvinyl acetal, etc. which were modified|denatured with aldehydes can also be used. The polymerization degree of polyvinyl alcohol-type resin is 1000 or more and 10000 or less normally, Preferably they are 1500 or more and 5000 or less.

The polarizer layer, which is a stretched layer to which the dichroic dye is adsorbed, is usually a process of applying a coating liquid containing the polyvinyl alcohol-based resin on a base film, a process of uniaxially stretching the obtained laminated film, uniaxially stretching lamination By dyeing the polyvinyl alcohol-based resin layer of the film with a dichroic dye, the dichroic dye is adsorbed to form a polarizer layer; It can be manufactured through the process of washing with water later. You may use the base film used in order to form a polarizer layer as a protective layer of a polarizer layer. You may peel and remove a base film from a polarizer layer as needed. The material and thickness of a base film may be the same as that of the thermoplastic resin film mentioned later and thickness.

The polarizer layer which is the stretched film or stretched layer to which the dichroic dye was adsorbed may be used as a linear polarizing plate as it is, and you may use it as a linear polarizing plate by forming a protective layer on the one side or both surfaces. As a protective layer, the thermoplastic resin film mentioned later can be used. The thickness of the linear polarizing plate obtained becomes like this. Preferably they are 2 micrometers or more and 40 micrometers or less.

The thermoplastic resin film is, for example, a cyclopolyolefin-based resin film; Cellulose acetate-type resin film which consists of resin, such as a triacetyl cellulose and a diacetyl cellulose; a polyester-based resin film made of a resin such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate-based resin film; (meth)acrylic resin film; Well-known films in the art, such as a polypropylene resin film, are mentioned. A polarizer layer and a protective layer can be laminated|stacked through the bonding layer mentioned later.

The thickness of the thermoplastic resin film is usually 100 µm or less, preferably 80 µm or less, more preferably 60 µm or less, still more preferably 40 µm or less, still more preferably from the viewpoint of reducing the thickness of the thermoplastic resin film. It is 30 micrometers or less, and is 5 micrometers or more normally, Preferably it is 10 micrometers or more.

The hard-coat layer may be formed on the thermoplastic resin film. The hard-coat layer may be formed in one surface of a thermoplastic resin film, and may be formed in both surfaces. By providing a hard-coat layer, it can be set as the thermoplastic resin film which improved hardness and scratch resistance. A hard-coat layer can be carried out similarly to the hard-coat layer formed in the above-mentioned resin film, and can be formed.

(a polarizer layer that is a liquid crystal layer)

The polymerizable liquid crystal compound used to form the liquid crystal layer is a compound having a polymerizable reactive group and exhibiting liquid crystallinity. A polymerizable reactive group is a group which participates in a polymerization reaction, and it is preferable that it is a photopolymerizable reactive group. The photopolymerization reactive group refers to a group capable of participating in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. there is. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The kind of polymerizable liquid crystal compound is not specifically limited, A rod-shaped liquid crystal compound, a disk-shaped liquid crystal compound, and a mixture thereof can be used. A thermotropic liquid crystal or a lyotropic liquid crystal may be sufficient as the liquid crystal of a polymeric liquid crystal compound, and a nematic liquid crystal or a smectic liquid crystal may be sufficient as a normal order structure.

As a dichroic dye used for the polarizer layer which is a liquid crystal layer, it is preferable to have an absorption maximum wavelength (λMAX) in the range of 300-700 nm. As such a dichroic dye, although an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, an anthraquinone dye, etc. are mentioned, for example, Among these, an azo dye is preferable. As an azo dye, a monoazo dye, a bisazo dye, a trisazo dye, a tetrakis azo dye, a stilbenazo dye, etc. are mentioned, Preferably they are a bisazo dye and a trisazo dye. Although a dichroic dye may be individual or may combine 2 or more types, it is preferable to combine 3 or more types. In particular, it is more preferable to combine three or more types of azo compounds. A part of the dichroic dye may have a reactive group, and may have liquid crystallinity.

The polarizer layer, which is a liquid crystal layer, is formed by, for example, applying a composition for forming a polarizer layer comprising a polymerizable liquid crystal compound and a dichroic dye on an alignment film formed on a base film, and polymerizing and curing the polymerizable liquid crystal compound. can do. On a base film, you may form a polarizer layer by apply|coating the composition for polarizer layer formation, forming a coating film, and extending|stretching this coating film with a base film. You may use the base film used in order to form a polarizer layer as a protective layer of a polarizer layer. The material and thickness of the base film may be the same as the material and thickness of the above-described thermoplastic resin film.

A composition for forming a polarizer layer comprising a polymerizable liquid crystal compound and a dichroic dye, and a method for manufacturing a polarizer layer using the composition include Japanese Patent Laid-Open Nos. 2013-37353, 2013-33249, and Japanese Patents. What was described in Unexamined-Japanese-Patent No. 2017-83843 etc. can be illustrated. In addition to the polymerizable liquid crystal compound and the dichroic dye, the composition for polarizer layer formation may further contain additives, such as a solvent, a polymerization initiator, a crosslinking agent, a leveling agent, antioxidant, a plasticizer, and a sensitizer. These components may use only 1 type, respectively, and may use them in combination of 2 or more type.

The polymerization initiator which may be contained in the composition for forming a polarizer layer is a compound capable of initiating a polymerization reaction of a polymerizable liquid crystal compound, and a photopolymerization initiator is preferable from the viewpoint of being able to initiate a polymerization reaction under lower temperature conditions. . Specifically, a photoinitiator capable of generating active radicals or acids by the action of light is exemplified, and among them, a photoinitiator capable of generating radicals by the action of light is preferable. To [ content of a polymerization initiator / 100 weight part of total amounts of a polymeric liquid crystal compound ], Preferably they are 1 mass part or more and 10 mass parts or less, More preferably, they are 3 mass parts or more and 8 mass parts or less. If it exists in this range, reaction of a polymeric group will fully advance and it will be easy to stabilize the orientation state of a liquid crystal compound.

The thickness of the polarizer layer which is a liquid crystal layer is 10 micrometers or less normally, Preferably they are 0.5 micrometer or more and 8 micrometers or less, More preferably, they are 1 micrometer or more and 5 micrometers or less.

The polarizer layer which is a liquid crystal layer may be used as a linear polarizing plate, without peeling and removing a base film, and it is good also as a linear polarizing plate by peeling and removing a base film from a polarizer layer. The polarizer layer, which is a liquid crystal layer, may be used as a linear polarizing plate by forming a protective layer on one or both surfaces thereof. As a protective layer, the above-mentioned thermoplastic resin film can be used.

The polarizer layer which is a liquid crystal layer may have an overcoat layer on one side or both surfaces of a polarizer layer for the purpose of protection of a polarizer layer, etc. An overcoat layer can be formed by apply|coating the material (composition) for forming an overcoat layer on a polarizer layer, for example. As a material which comprises an overcoat layer, a photocurable resin, a water-soluble polymer, etc. are mentioned, for example. As a material constituting the overcoat layer, (meth)acrylic resin, polyvinyl alcohol-based resin, or the like can be used.

The polarizing plate 103 is arrange|positioned so that a linear polarizing plate may become the 1st adhesive layer 102 side with respect to the retardation layer. The outermost layer constituting the polarizing plate 103 and in contact with the first pressure-sensitive adhesive layer 102 is preferably a base film or a protective layer included in the linear polarizing plate.

(retardation layer)

The number of retardation layers may be one, and two or more layers may be sufficient as them. The retardation layer may have the overcoat layer which protects the surface, the base film etc. which support the retardation layer. The retardation layer may include a λ/4 layer and further include at least one of a λ/2 layer or a positive C layer. When the retardation layer contains the λ/2 layer, the λ/2 layer and the λ/4 layer are sequentially laminated from the linear polarizing plate side. When the retardation layer includes the positive C layer, the λ/4 layer and the positive C layer may be sequentially laminated from the linear polarizing plate side, or the positive C layer and the λ/4 layer may be laminated sequentially from the linear polarizing plate side. The thickness of the retardation layer 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 may be formed from the resin film exemplified as the material for the protective layer, or may be formed from a layer obtained by curing the polymerizable liquid crystal compound. The retardation layer may further include an alignment film. The retardation layer may have a bonding layer for bonding the λ/4 layer, the λ/2 layer, and the positive C layer together.

When curing a polymerizable liquid crystal compound to form a retardation layer, a retardation layer can be formed by apply|coating and hardening a composition containing a polymerizable liquid crystal compound to a base film. You may form an orientation film between a base film and an application layer. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film. When forming a retardation layer with the layer which hardens|cures a polymeric liquid crystal compound, the retardation layer may be contained in the optical laminated body in the form which has an orientation film and a base film. A phase difference layer can be bonded together with a linear polarizing plate through a bonding layer.

[Second adhesive layer]

The 2nd adhesive layer 104 is interposed between the polarizing plate 103 and the back plate 105, and these are bonded together. One layer may be sufficient as the 2nd adhesive layer 104, Although what consists of two or more layers may be sufficient, Preferably it is one layer.

The composition and mixing components of the pressure-sensitive adhesive composition constituting the second pressure-sensitive adhesive layer 104, the type of the pressure-sensitive adhesive composition (whether active energy ray curing type or thermosetting type, etc.), additives that can be formulated in the pressure-sensitive adhesive composition, the production of the second pressure-sensitive adhesive layer The method and the thickness of the second pressure-sensitive adhesive layer are the same as those shown in the description of the first pressure-sensitive adhesive layer 102 described above. The second pressure-sensitive adhesive layer 104 may be the same as or different from the first pressure-sensitive adhesive layer 102 in the composition, blending component, thickness, and the like of the pressure-sensitive adhesive composition.

From the viewpoint of improving the cohesive force of the second pressure-sensitive adhesive layer 104, the gel fraction of the second pressure-sensitive adhesive layer 104 is preferably 60% or more, more preferably 70% or more, and still more preferably 75%. or more, preferably 95% or less, more preferably 90% or less, still more preferably 85% or less. The gel fraction is measured according to the method described in Examples below. A gel fraction can be adjusted by changing the kind and content of the (meth)acrylic-type monomer which comprises the base polymer in an adhesive composition, an additive, a crosslinking degree, etc.

In the optical laminate 100, when the gel fraction of the first pressure-sensitive adhesive layer is R1 (%) and the gel fraction of the second pressure-sensitive adhesive layer is R2 (%), the following relational expression:

R1<R2

It is desirable to satisfy Usually, when the optical laminate 100 is bent with the front plate 101 turned inside, a tensile stress stronger than that of the first adhesive layer 102 on the inner diameter side is generated in the second adhesive layer 104 on the outer diameter side. . When R1 and R2 satisfy the above relational expression, since the cohesive force of the pressure-sensitive adhesive layer on the outer diameter side becomes larger than the cohesive force of the pressure-sensitive adhesive layer on the inner diameter side, even if the optical laminate 100 is statically bent with the front plate 101 inside, the adhesive There exists a tendency for generation|occurrence|production of the bubble between a layer and the layer which contact|connects an adhesive layer and in an adhesive layer to be suppressed.

In the case of bending the optical laminate 100 with the front plate 101 facing outward, R1 and R2 are the following relational expressions:

R1≥R2

It is preferable to satisfy the following relation:

R1>R2

It is more preferable to satisfy When R1 and R2 satisfy the above relational expression, since the cohesive force of the pressure-sensitive adhesive layer on the outer diameter side becomes larger than the cohesive force of the pressure-sensitive adhesive layer on the inner diameter side, even if the optical laminate 100 is statically bent with the front plate 101 outside, the adhesive There exists a tendency for generation|occurrence|production of the bubble between a layer and the layer which contact|connects an adhesive layer and in an adhesive layer to be suppressed.

From the viewpoint of improving the cohesive force of the second pressure-sensitive adhesive layer 104, when the second pressure-sensitive adhesive layer 104 is used as a reference pressure-sensitive adhesive layer having a thickness of 150 μm, the shear modulus at a temperature of 25° C. is preferably 0.01 MPa or more. and more preferably 0.02 MPa or more, preferably 0.50 MPa or less, and more preferably 0.10 MPa or less. When the shear modulus of elasticity of the 2nd adhesive layer 104 is this range, even if it bends, the optical laminated body 100 is hard to produce cohesive failure, and it is hard to generate|occur|produce a bubble either. A shear modulus can be adjusted by changing the kind and content of the monomer which comprises the base polymer in an adhesive composition, an additive, a crosslinking degree, etc. A shear modulus can be measured by the method as described in the Example mentioned later.

[bonding layer]

The optical laminated body 100 can contain the bonding layer for bonding two layers together. A bonding layer is a layer comprised from an adhesive or an adhesive agent. The adhesive composition similar to the adhesive composition which comprises the 1st adhesive layer 102 mentioned above can be used for the adhesive used as a material of a bonding layer. The bonding layer is different from the other adhesive, for example, the adhesive constituting the first adhesive layer 102, a (meth)acrylic adhesive, a styrene-based adhesive, a silicone-based adhesive, a rubber-based adhesive, a urethane-based adhesive, a polyester-based adhesive, and an epoxy-based adhesive. It can also be formed using a copolymer adhesive etc.

As an adhesive agent used as the material of a bonding layer, it can form, for example combining 1 type, or 2 or more types among a water-system adhesive agent, an active energy ray hardening-type adhesive agent, etc. Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution and a water-based two-component urethane-based emulsion adhesive. The active energy ray-curable adhesive is an adhesive that is cured by irradiating active energy rays such as ultraviolet rays, for example, an adhesive containing a polymerizable compound and a photopolymerization initiator, an adhesive containing a photoreactive resin, a binder resin, and a photoreactive crosslinking agent and adhesives containing Examples of the polymerizable compound include photopolymerizable monomers such as a photocurable epoxy monomer, a photocurable acrylic monomer, and a photocurable urethane monomer, and an oligomer derived from these monomers. As said photoinitiator, the compound containing the substance which irradiates active energy rays, such as an ultraviolet-ray, and generate|occur|produces the active species of a neutral radical, an anion radical, and a cationic radical is mentioned.

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.

The two opposing surfaces bonded together through the bonding layer may perform corona treatment, a plasma treatment, a flame treatment, etc. beforehand, and may have a primer layer etc.

[back board]

As the back plate 105, a plate-like body capable of transmitting light, a component 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 plate 105 may be constituted by only one layer, may be constituted by two or more layers, and those exemplified for the plate-shaped body described in the front plate 101 can be used.

As a component used for the normal display apparatus used for the back plate 105, a touch sensor panel, an organic electroluminescent display element, etc. are mentioned, for example. Examples of the stacking order of the components in the display device include window film/circularly polarizing plate/touch sensor panel/organic EL display element, window film/touch sensor panel/circularly polarizing plate/organic EL display element, and the like.

(Touch sensor panel)

The touch sensor panel is not limited as long as it is a panel having a sensor (ie, a touch sensor) capable of detecting a touched position. The detection method of the touch sensor is not limited, and a touch sensor panel such as a resistive film method, a capacitive coupling method, an optical sensor method, an ultrasonic method, an electromagnetic inductive coupling method, and a surface acoustic wave method is exemplified. Since it is low cost, the touch sensor panel of a resistive film type and a capacitive coupling type is used suitably.

As an example of a resistive touch sensor, a pair of substrates disposed opposite to each other, an insulating spacer sandwiched between the pair of substrates, a transparent conductive film provided as a resistive film on the entire surface of the inner side of each substrate; The member constituted by the position detection circuit is mentioned.

In an image display device provided with a resistive touch sensor, when the surface of the front plate is touched, the opposing resistive film is short-circuited, and a current flows through the resistive film. The touch position detecting circuit detects a change in voltage at this time, and the touched position is detected.

As an example of the capacitive coupling type touch sensor, the member comprised by the board|substrate, the transparent electrode for position detection provided on the front surface of the board|substrate, and a touch position detection circuit is mentioned. In an image display device provided with a capacitive coupling type touch sensor, when the surface of the front plate is touched, the transparent electrode is grounded through the human body's capacitance at the touched point. The touch position detection circuit detects the grounding of the transparent electrode, and the touched position is detected.

The thickness of a touch sensor panel may be 5 micrometers or more and 2000 micrometers or less, for example, Preferably they are 5 micrometers or more and 100 micrometers or less, More preferably, they are 5 micrometers or more and 50 micrometers or less.

The touch sensor panel may be a member in which the pattern of the touch sensor was formed on the base film. The illustration of the base film may be the same as the illustration in description of the above-mentioned thermoplastic resin film. In addition, the touch sensor panel may be what was transcribe|transferred by the to-be-adhered body from a base film through an adhesive layer. The thickness of the touch sensor pattern may be, for example, 1 µm or more and 20 µm or less.

[Manufacturing method of optical laminated body]

The optical laminated body 100 can be manufactured according to the method including the process of bonding together the layers which comprise the optical laminated body 100 via an adhesive layer. When bonding layers through an adhesive layer or a bonding layer, it is preferable to perform surface activation processing, such as a corona treatment, with respect to one or both of bonding surfaces for the purpose of adjusting adhesive force. The conditions of corona treatment can be set suitably, and conditions may differ from one surface of a bonding surface and the other surface.

<Display device>

The display device according to the present invention includes the optical laminate 100 . A display apparatus is not specifically limited, For example, Image display apparatuses, such as an organic electroluminescent display apparatus, an inorganic EL display apparatus, a liquid crystal display apparatus, and an electroluminescent display apparatus, are mentioned. A touch sensor may be further laminated|stacked on the optical laminated body, and a display apparatus may have a touchscreen function. The display device including the optical laminate of the present invention exhibits durability excellent in static bending, and can be used as a flexible display capable of bending or winding.

In the display device, the optical laminate 100 is disposed on the viewing side of the display element of the display device with the front plate 101 facing outward (the side opposite to the display element side, that is, the viewing side). The display device can be bent with the front plate 101 side inside. The display device may be bent with the front plate 101 side facing outward.

The display device according to the present invention can be used as a mobile device such as a smart phone or tablet, a television, a digital photo frame, an electronic signage, a measuring instrument or instrument, an office device, a medical device, a computer device, and the like.

Example

Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these.

[Adhesive layer]

2-ethylhexyl acrylate (2-EHA) shown in Table 1, n-butyl acrylate (n-BA), acrylic acid ( AA), 2-hydroxyethyl acrylate (2-HEA), and a monomer mixture consisting of isodecyl acrylate (IDA) were added. To remove oxygen, nitrogen gas was refluxed for 1 hour, and then the solution was maintained at 60°C. After uniformly mixing the monomer mixture, a photoinitiator benzyl dimethyl ketal (I-651) and 1-hydroxycyclohexylphenyl ketone (I-184) were added in the amounts shown in Table 1. A UV lamp (10 mW) was irradiated while stirring to prepare (meth)acrylic polymers A1 to A7.

The obtained (meth)acrylic polymers A1 to A7, isodecyl acrylate (IDA), compound I, and benzophenone (BPO) were mixed in the amounts shown in Table 2 to prepare pressure-sensitive adhesive compositions B1 to B7.

[Tuesday 3]

(화합물 I)

(Compound I)

The pressure-sensitive adhesive compositions B1 to B7 were applied to a thickness of 25 μm on a release film A (polyethylene terephthalate film, thickness 38 μm) coated with a silicone release agent. The peeling film B (polyethylene terephthalate film, 38 micrometers in thickness) was bonded together on it, UV irradiation was performed, and the adhesive sheet which consists of peeling film A / adhesive layer / peeling film B was produced. The UV irradiation conditions were an accumulated light quantity of 400 mJ/cm 2 and an illuminance of 1.8 mW/cm 2 (UVV standard).

The sources of acquisition of the used compound are as follows.

2-EHA: TOKYO CHEMICAL INDUSTRY CO., LTD., Japan

n-BA：TOKYO CHEMICAL INDUSTRY CO.,LTD., Japan

AA：TOKYO CHEMICAL INDUSTRY CO.,LTD., Japan

2-HEA：TOKYO CHEMICAL INDUSTRY CO.,LTD., Japan

IDA：Miwon　specialty　chemical, Korea

I-651: BASF, Germany

I-184: BASF, Germany

BPO：TOKYO CHEMICAL INDUSTRY CO.,LTD., Japan

[Front panel]

As the front plate 101, a film in which a hard coat layer was formed on one surface of the resin film was prepared. The resin film was a 40-micrometer-thick polyimide-type resin film. The hard-coat layer was 10 micrometers in thickness and was a layer formed from the composition containing the dendrimer compound which has a polyfunctional acrylic group at the terminal.

[Circular Polarizer]

A circularly polarizing plate was prepared as the polarizing plate 103 . A linear polarizing plate having a triacetyl cellulose (TAC) film (KC2UA, manufactured by Konica Minolta, Inc., 25 μm thick), an alignment film, a linear polarizer layer, and an overcoat layer in this order was prepared. The linear polarizer layer was formed using the composition containing a polymeric liquid crystal compound and a dichroic dye, and thickness was 2 micrometers. The overcoat layer was a polyvinyl alcohol resin layer and had a thickness of 1.0 µm.

A phase difference laminate was laminated|stacked on the overcoat layer side of a linear polarizing plate via an adhesive layer, and the circularly polarizing plate was obtained. The retardation layered product had a λ/4 retardation layer, an adhesive layer, and a positive C layer in order from the linear polarizing plate side. The λ/4 phase difference layer was a cured layer of a polymerizable liquid crystal compound, and had a thickness of 3 µm. The thickness of the pressure-sensitive adhesive layer was 5 µm. The positive C layer was a cured layer of a polymerizable liquid crystal compound, and had a thickness of 3 µm.

[back board]

As the back plate 105, a touch sensor in which a touch sensor pattern layer, an adhesive layer, and a base layer were laminated in this order was prepared. The touch sensor pattern layer included an ITO layer as a transparent conductive layer and a cured layer of an acrylic resin composition as a separation layer, and had a thickness of 7 µm. The adhesive layer was provided on the separation layer side of the touch sensor pattern layer, and had a thickness of 3 µm. The cyclic olefin resin (COP) film (ZF-14, the product made in ZEON CORPORATION, Japan, 23 micrometers in thickness) was used for the base material layer.

[Production of optical laminate]

As shown in Table 3, the pressure-sensitive adhesive sheet composed of the pressure-sensitive adhesive composition shown in Table 2 was used as the first pressure-sensitive adhesive layer 102 , and the side without the hard coat layer of the front plate 101 and the TAC film side of the polarizing plate 103 . was pasted together. In addition, as shown in Table 3, the pressure-sensitive adhesive sheet made of the pressure-sensitive adhesive composition shown in Table 2 is used as the second pressure-sensitive adhesive layer 104, and the phase difference layer side of the circularly polarizing plate and the touch sensor pattern layer side of the touch sensor are bonded together, The optical laminated body 100 (Examples 1-5 and Comparative Examples 1 and 2) of the layer structure shown in 1 was produced. The double-sided corona treatment was performed to the bonding surface of a front plate, a circularly-polarizing plate, a touch sensor, and an adhesive layer before bonding. For the corona treatment, TEC-4 AX (manufactured by USHIO INC.) was used. The ratio of the low molecular weight component in the suspension prepared by immersing the pressure-sensitive adhesive layer in ethyl acetate, the glass transition temperature of the eluted component, the gel fraction of the pressure-sensitive adhesive layer, the shear modulus, and the static bending durability of the optical laminate 100 are described below. was measured according to A result is shown in Table 3.

<thickness of layer>

It measured using the contact type film thickness measuring apparatus ("MS-5C" manufactured by Nikon Corporation). About the polarizer layer and the orientation film, it measured using the laser microscope ("OLS3000" by Olympus Corporation).

<Gel fraction of pressure-sensitive adhesive layer>

The pressure-sensitive adhesive sheet was cut to a size of 20 mm x 20 mm, the pressure-sensitive adhesive layer was wrapped in a polyester mesh (mesh size 200), and the mass was weighed with a precision balance. The mass of the mesh alone was subtracted to calculate the mass of only the pressure-sensitive adhesive layer. Let the mass at this time be M1. Next, the pressure-sensitive adhesive layer wrapped in the polyester mesh was immersed in ethyl acetate at a temperature of 23°C for 24 hours. After that, the pressure-sensitive adhesive layer was taken out and air-dried for 24 hours under an environment of a temperature of 23°C and a relative humidity of 50%, and further dried in an oven at 80°C for 12 hours. After drying, the mass was measured with a precision balance, the mass of the said mesh independent was subtracted, and the mass of only the adhesive layer was computed. Let the mass at this time be M2. The gel fraction (%) is represented by (M2/M1) x 100.

<The ratio of the low molecular weight component to the component eluted from the pressure-sensitive adhesive layer>

With reference to FIG. 2, the calculation method of the ratio of the low molecular-weight component to the component eluted by immersing an adhesive layer in ethyl acetate is demonstrated. The pressure-sensitive adhesive sheet was cut to a size of 20 mm x 20 mm, and the pressure-sensitive adhesive layer 202 was wrapped in a polyester mesh 201 (mesh size 200). The pressure-sensitive adhesive layer 202 wrapped in the polyester mesh 201 was immersed in ethyl acetate 203 (60 g) at a temperature of 23° C. for 24 hours (a). In addition, ethyl acetate was not stirred during immersion. The adhesive layer 202 wrapped in the said polyester mesh 201 was taken out, and the ethyl acetate liquid (suspension solution 204) containing the component eluted from the adhesive layer was obtained (b). The suspension (204) was dried at 100°C for 1 hour, and ethyl acetate (203) was evaporated (c). A sample for measuring the weight average molecular weight (Mw) was prepared by adding tetrahydrofuran (205) so that the concentration of the eluted component was about 0.05 mass% (d).

The weight average molecular weight (Mw) was determined by size exclusion chromatography (SEC) using tetrahydrofuran as a mobile phase as a number average molecular weight (Mn) in terms of polystyrene. Specifically, the following operation was performed. 10 μL of the sample was injected into the SEC. The mobile phase was flowed at a flow rate of 1.0 mL/min. As a column, PLgel MIXED-B (300×7.5 mm, part number: PL1110-6100, manufactured by Polymer Laboratories Ltd.) was used. A differential refractive index (RI) detector (trade name: Agilent GPC) was used as the detector.

Using the calculation method shown below, the ratio of the component whose weight average molecular weight is 100,000 or less was calculated. First, a calibration curve (calibration 　curve) of a standard sample (polystyrene) was prepared. Based on the calibration curve, the dissolution time (Retention = time: Rt) at which the weight average molecular weight (Mw) becomes 100,000 was calculated.

The measured sample is shown as a graph in which the elution time is on the abscissa axis and the detected amount is on the ordinate axis, and the following formula:

｛(area of 100,000 or less weight average molecular weight)/(total area of peaks) ｝×100 (%)

The value calculated as , was taken as the ratio of the low molecular weight component to the component eluted from the pressure-sensitive adhesive layer.

<The glass transition temperature of the component eluted from the pressure-sensitive adhesive layer>

Similar to the measurement of the gel fraction, the suspension obtained by immersing the pressure-sensitive adhesive layer in ethyl acetate was dried at 100°C for 1 hour. Then, the glass transition temperature (Tg) of the component contained in the suspension was measured using a differential scanning calorimeter (DSC, Q-1000, manufactured by TA Instruments).

<Shear modulus of adhesive layer>

The shear modulus was measured using a viscoelasticity measuring apparatus (MCR-301, manufactured by Anton Paar). The adhesive sheet was made into width 20mm x length 20mm, the peeling film was peeled off, and it laminated|stacked in multiple sheets so that thickness might be set to 150 micrometers. After bonding the laminated pressure-sensitive adhesive layer to the glass plate, in the state of bonding to the measuring chip, measurement is performed under the conditions of a frequency of 1.0 Hz, a deformation amount of 1%, and a temperature increase rate of 5°C/min in a temperature range of -20°C to 100°C, and 25°C The shear modulus value was confirmed.

<Static bending durability test>

Fig. 3 shows the static bending durability test (mandrel bending test) method. First, the optical laminate 100 was cut into a 1 cm x 10 cm test piece. The front plate 101 side of the optical laminate 100 was placed on the test plate 502, and an iron rod 501 having a diameter of 5 mm was placed thereon (FIG. 3(A)). The front plate 101 wound around the iron rod 501 was folded by hand so that it was inside and fixed (FIG. 3(B)).

Between the polarizing plate 103 and the first pressure-sensitive adhesive layer 102 and the second pressure-sensitive adhesive layer 104, or between the first pressure-sensitive adhesive layer 102 and the second pressure-sensitive adhesive layer 104, based on the period in which bubbles do not generate, static Flexural durability was evaluated as follows. Generation|occurrence|production of a bubble was judged by observation under an optical microscope.

A: Bubbles did not generate|occur|produce when 48 hours passed.

B: For more than 24 hours, bubbles were generated within 48 hours.

C: For more than 12 hours, bubbles were generated within 24 hours.

D: Bubbles were generated within 12 hours.

100 optical laminates,
101 front panel,
102 first adhesive layer;
103 polarizer,
104 second adhesive layer;
105 backplate,
201 mesh,
202 adhesive layer,
203 ethyl acetate;
204 Suspension,
205 tetrahydrofuran,
501 iron rod,
502 Trial.

Claims (8)

A front plate, a first adhesive layer, a polarizing plate, a second adhesive layer, and a rear plate are provided in this order,
In the first pressure-sensitive adhesive layer, among the components eluted by immersion in ethyl acetate, the proportion of components having a weight average molecular weight of 100,000 or less is 10% by mass or more and 30% by mass or less,
Each of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer consists of one layer,
When the gel fraction of the first adhesive layer is R1 (%) and the gel fraction of the second adhesive layer is R2 (%), the following relational formula:
R1<R2
is satisfied with
The gel fraction (R1) of the first pressure-sensitive adhesive layer and the gel fraction (R2) of the second pressure-sensitive adhesive layer are 60% or more and 85% or less, the optical laminate. According to claim 1,
The said 2nd adhesive layer is an optical laminated body whose ratio of the component whose weight average molecular weight is 100,000 or less among the components immersed in ethyl acetate and eluted is 10 mass % or more and 30 mass % or less. 3. The method of claim 1 or 2,
The glass transition temperature of the component eluted by immersing the first pressure-sensitive adhesive layer in ethyl acetate, and the glass transition temperature of the component eluted by immersing the second pressure-sensitive adhesive layer in ethyl acetate are -70 ° C. or more and -40 ° C. or less, respectively, optical laminate. delete delete delete A display device comprising the optical laminate according to claim 1 or 2. 8. The method of claim 7,
A display device capable of being bent with the front plate side inside.

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