KR20210111686A - Optical laminate and display device - Google Patents

Abstract

Provided are an optical laminate, which suppresses the generation of air bubbles when bent, and a display device comprising the same. The optical laminate comprises: a front plate; a first adhesive layer formed using a first adhesive composition; a polarizing plate; a second adhesive layer formed using a second adhesive composition; and a back plate, in the order, wherein the following relational equations (1) and (2) are satisfied when the shear recovery rate at 25℃ before and after the deformation repeated load test is R1A[%] and R1B[%], respectively in a first reference pressure-sensitive layer having a thickness of 200 μm formed using the first adhesive composition, and the shear recovery rate at 25℃ before and after the deformation repeated load test is R2A[%] and R2B[%] in a second reference pressure-sensitive layer having a thickness of 200 μm formed using the second adhesive composition. The relational equation (1) is represented by Delta;R1={(R1A)-(R1B)}/200<=0.2 and the relational equation (2) is represented by ΔR2={(R2A)-(R2B)}/200<=0.2.

Description

Optical laminate and display device {OPTICAL LAMINATE AND DISPLAY DEVICE}

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

In Patent Document 1, when a laminate having a plurality of pressure-sensitive adhesive layers is folded, the storage elastic modulus of the convex outermost pressure-sensitive adhesive layer is substantially equal to or smaller than the storage elastic modulus of the other pressure-sensitive adhesive layers.

Patent Document 2 discloses a deformable pressure-sensitive adhesive composition for a display that does not float or break even at a very low temperature of -20°C while maintaining the adhesive properties at room temperature and high temperature.

Patent Document 1: Japanese Patent Laid-Open No. 2018-28573 Patent Document 2: Korean Patent Laid-Open No. 10-2019-0069334

When the display device containing the optical laminated body which has several adhesive layers was bent, a bubble may generate|occur|produce in the adhesive layer in an optical laminated body.

An object of this invention is to provide the optical laminated body in which generation|occurrence|production of the bubble was suppressed even if it bends, and the display apparatus containing this.

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

[1] 　 A front plate, a first pressure-sensitive adhesive layer formed using the first pressure-sensitive adhesive composition, a polarizing plate, a second pressure-sensitive adhesive layer formed using the second pressure-sensitive adhesive composition, and a back plate are provided in this order,

In the first reference pressure-sensitive adhesive layer having a thickness of 200 μm formed using the first pressure-sensitive adhesive composition, the shear recovery rate at a temperature of 25° C. before and after the deformation cyclic load test is R1A [%] and R1B [%], respectively, and 2 In the second reference pressure-sensitive adhesive layer having a thickness of 200 μm formed using the pressure-sensitive adhesive composition, the shear recovery rate at a temperature of 25° C. before and after the deformation cyclic load test is R2A [%] and R2B [%], respectively. An optical laminate which satisfies the relational expressions (1) and (2).

ΔR1=｛(R1A)-(R1B)｝/200≤0.2　　(1)

ΔR2=｛(R2A)-(R2B)｝/200≤0.2　　(2)

[2] 　 The optical laminate according to [1], which further satisfies the following relational expression (3).

R1A≤R2A　　(3)

[3] 　 The optical laminate according to [1] or [2], which further satisfies the following relational expression (4).

ΔR1≤ΔR2　　(4)

[4] The optical laminate according to any one of [1] to [3], wherein R1A [%] is 20% or more.

[5] The optical laminate according to any one of [1] to [4], wherein the back plate is a touch sensor panel.

[6] A display device comprising the optical laminate according to any one of [1] to [5].

[7] 　 The display device according to [6], wherein the front plate side can be bent inside.

ADVANTAGE OF THE INVENTION According to this invention, even if it bends, the optical laminated body and the display apparatus in which generation|occurrence|production of the bubble was suppressed can be provided.

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 sectional drawing which shows typically the manufacturing method of the optical laminated body which concerns on this invention.

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 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>

A schematic cross-sectional view of an optical laminate according to one embodiment of the present invention is shown in FIG. 1 . The optical laminate 100 includes a front plate 101 , a first adhesive layer 102 , a polarizing plate 103 , a second adhesive layer 104 , and a rear plate 105 in this order. The first pressure-sensitive adhesive layer 102 is formed of a first pressure-sensitive adhesive composition, and the second pressure-sensitive adhesive layer 104 is formed of a second pressure-sensitive adhesive composition. Hereinafter, the 1st adhesive layer 102 and the 2nd adhesive layer 104 may be collectively called an adhesive layer.

Although the thickness of the optical laminated body 100 is not specifically limited since it differs with the function calculated|required of an optical laminated body, the use of an optical laminated body, etc., For example, it is 30 micrometers or more and 1500 micrometers or less, Preferably it is 40 micrometers or more 1000. It is micrometer or less, More preferably, they are 50 micrometers or more and 500 micrometers or less.

The planar 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 corner 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 suitable for a bendable display device.

[Reduction rate of shear recovery rate and shear recovery rate by strain cyclic load test]

In the first reference pressure-sensitive adhesive layer having a thickness of 200 μm formed using the first pressure-sensitive adhesive composition, the shear recovery rate at a temperature of 25° C. before and after the deformation cyclic load test is R1A [%] and R1B [%], respectively, and the second pressure-sensitive adhesive In the second reference pressure-sensitive adhesive layer having a thickness of 200 μm formed using the composition, when the shear recovery rate at a temperature of 25° C. before and after the deformation cyclic load test is R2A [%] and R2B [%], respectively, the optical laminate ( 100) satisfies the following relational expressions (1) and (2).

ΔR1=｛(R1A)-(R1B)｝/200≤0.2　　(1)

ΔR2=｛(R2A)-(R2B)｝/200≤0.2　　(2)

In an optical laminate in which the front plate, the first pressure-sensitive adhesive layer, the polarizing plate, the second pressure-sensitive adhesive layer, and the rear plate are laminated in this order, when bent, air bubbles are easily generated in the pressure-sensitive adhesive layer, especially in the pressure-sensitive adhesive layer on the inner diameter side. It turned out to be easy. Even when the optical laminate 100 satisfying the formulas (1) and (2) is bent, the generation of bubbles is suppressed, and in particular, even when the optical laminate 100 is bent and the state is maintained for a certain period of time The generation of air bubbles is suppressed. In the present specification, suppression of the generation of air bubbles means, for example, that even when the optical laminate 100 is bent along an axis (mandrel) that is a cylindrical jig of 10 mm or less in diameter and left to stand for 24 hours, the pressure-sensitive adhesive layer It says that a bubble does not generate|occur|produce between the middle and the adhesive layer and the layer which contact|connects an adhesive layer. Hereinafter, this performance is also referred to as excellent in bending durability. Generation|occurrence|production of a bubble can be judged by observation under an optical microscope.

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

ΔR1 and ΔR2 are obtained by dividing the amount of decrease in the shear recovery rate before and after performing the strain cyclic load test by the thickness of the first reference pressure-sensitive adhesive layer or the second reference pressure-sensitive adhesive layer (200 µm). For this reason, the decrease amount of the shear recovery rate by the deformation|transformation repeated load test per 1 micrometer of thickness of the adhesive layer formed using the 1st adhesive composition or the 2nd adhesive composition is calculated|required. When ΔR1 and ΔR2 are small, it means that the shear recovery rate of the pressure-sensitive adhesive layer is less likely to decrease even if a strain repeated load test (accelerated test) is performed. That is, when ΔR1 and ΔR2 are small, even if repeated bending is performed, it is thought that the cohesive force of an adhesive is hard to fall and the performance of an adhesive is easy to maintain.

The optical laminate 100 preferably satisfies the following relational expressions (1') and (2').

ΔR1=｛(R1A)-(R1B)｝/200≤0.1　　(1')

ΔR2=｛(R2A)-(R2B)｝/200≤0.1　　(2')

When the optical laminated body 100 satisfy|fills Formula (1') and (2'), bending durability can be improved more. ?R1 and ?R2 may be, for example, 0.001 or more, or 0.003 or more.

The optical laminate 100 preferably further satisfies the following relational expression (4).

ΔR1≤ΔR2　　(4)

The optical laminate 100 more preferably satisfies the following relational expression (4').

ΔR1<ΔR2　　(4')

When the optical laminate 100 is bent with the front plate 101 inside, a greater stress is generated in the inner-diameter pressure-sensitive adhesive layer, ie, the first pressure-sensitive adhesive layer 102 , than the second pressure-sensitive adhesive layer 104 . The bending durability of the optical laminated body 100 can be improved more by arrange|positioning the adhesive layer with a small amount of change of the shear recovery rate before and behind performing a deformation|transformation repeated load test on the inner-diameter side with a larger stress.

The optical laminate 100 preferably satisfies the following relational expression (3).

R1A≤R2A　　(3)

The optical laminate 100 more preferably satisfies the following relational expression (3').

R1A<R2A　　(3')

When the pressure-sensitive adhesive layer has a high shear recovery rate and when deformation is removed, the pressure-sensitive adhesive layer returns to its original shape. difficult. In order to make it easy to relieve|moderate a deformation|transformation, it is preferable that the shear restoration rate of the adhesive layer used as an outer-diameter side is higher than the shear restoration rate of the adhesive layer on the inner-diameter side. Even when the optical laminated body 100 which satisfy|fills Formula (3) turns the front plate 101 inside and bends, generation|occurrence|production of a bubble is easy to be suppressed. The shear recovery rate of the adhesive layer can be calculated|required according to the method described in the column of the Example mentioned later.

From the viewpoint of improving the surface hardness of the optical laminate 100, the shear recovery rates R1A and R2A before the strain repeated load test are preferably 20% or more, more preferably 30% or more, and more preferably 40% More than that. The shear recovery rates R1B and R2B after the strain cyclic load test are preferably 15% or more, and more preferably 30% or more. The upper limit is not particularly limited, and the shear recovery rates R1A and R2A before the strain cyclic load test are, for example, 100% or less, may be 65% or less, may be less than 60%, or may be 55% or less. Although the upper limit is not particularly limited as long as the formulas (1) and (2) are satisfied, the shear recovery rates R1B and R2B after the strain cyclic load test are, for example, 50% or less, and may be 40% or less.

The shear recovery rates R1A and R2A before the strain repeated test, and the shear recovery ratios R1B and R2B after the strain repetitive test are the type and compounding amount of monomers constituting the base polymer included in the pressure-sensitive adhesive composition, the type and compounding amount of the polymerization initiator, the type and compounding amount of the active energy ray, and By adjusting the irradiation amount, etc., it can be set as a desired numerical range.

[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 101 may be comprised by only 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.), a glass-made plate-shaped object (for example, a glass plate, a glass film, etc.), a resin plate-shaped object, and glass and laminates of plate-shaped bodies. The front plate 101 may constitute the outermost surface of the display device.

The thickness of the front plate 101 may be, for example, 10 µm or more and 300 µm or less, preferably 20 µm or more and 200 µm or less, and more preferably 30 µm or more and 100 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.

Examples of the resin constituting the resin plate-shaped 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 polyether ether ketone, polyether sulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyamideimide. These polymers 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 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 an acrylic resin, a silicone resin, a polyester resin, a urethane resin, an amide resin, and an epoxy resin. 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 it has 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, the tempered glass for a display is used preferably as a glass plate. The thickness of a glass plate may be 10 micrometers or more and 1000 micrometers or less, for example, and 10 micrometers or more and 100 micrometers or less may be sufficient as them. 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 , a blue light cut function, a viewing angle adjustment function, and the like may be provided.

[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. Although the 1st adhesive layer 102 may consist of one layer and may consist of two or more layers, Preferably it consists of 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-curable 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 (meth)butyl acrylate, (meth)ethyl acrylate, (meth)acrylate isooctyl, (meth)acrylic acid 2-ethylhexyl, 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 amido group, an amino group, an epoxy group, etc. are mentioned.

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 active energy ray irradiation, and can be adhered to an adherend such as a film, and can be irradiated with active energy rays It has the property of being able to adjust the adhesion by hardening by It is preferable that an active energy ray hardening-type adhesive composition is an ultraviolet curable type. The active energy ray-curable adhesive composition further contains an active energy ray-polymerizable compound other than a base polymer and a crosslinking agent. You may contain a photoinitiator, a photosensitizer, etc. as needed.

As an active-energy-ray-polymerizable compound, For example, the (meth)acrylate monomer which has at least 1 piece(s) of (meth)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 can be heard When a (meth)acrylic compound having a cyclohexyl group or a (meth)acrylic compound having an ethoxy group is used as the active energy ray polymerizable compound, the cohesive force in the pressure-sensitive adhesive layer is improved, and the formulas (1) and (2) are Easier to be satisfied Examples of the (meth)acrylic compound having a cyclohexyl group include Miramer M1130 and Miramer M1150 manufactured by Miwon Specialty Chemical. Examples of the (meth)acrylic compound having an ethoxy group include Miramer M140, Miramer M142, and Miramer M144 manufactured by Miwon Specialty Chemical. The pressure-sensitive adhesive composition may contain 0.1 parts by mass or more or 5 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 30 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less Or 2 parts by mass or less may be included.

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 with respect to 100 mass parts of solid content of an adhesive composition, for example.

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 or other inorganic powders, etc.), antioxidants, Additives such as ultraviolet absorbers, dyes, pigments, colorants, defoamers, corrosion inhibitors, and photoinitiators may be included.

The first pressure-sensitive adhesive layer 102 may be formed by applying the organic solvent dilution solution of the pressure-sensitive adhesive composition on a substrate and drying the mixture. 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.

[Polarizer]

The polarizing plate 103 may be, for example, a linear polarizing plate, a circularly polarizing plate, or an elliptically 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 an 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 linearly polarizing plate has a function of selectively transmitting linearly polarized light in any one direction from non-polarized light rays such as natural light. A linear polarizing plate contains 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 is oriented A layer etc. can be provided as a polarizer layer. When a dye is dispersed and oriented in an anisotropic medium, it may appear colored in a certain direction and appear almost colorless in a direction perpendicular to this. A pigment showing this phenomenon is called a dichroic pigment. The linear polarizing plate using the liquid crystal layer as a polarizer layer is preferable because there is no restriction|limiting in a bending direction compared with the stretched film or stretched layer which made the dichroic dye adsorb|suck.

(1) A polarizer layer which is a stretched film or 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 boric acid aqueous solution, and the process of washing with water after the process with boric acid aqueous 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 with 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 compound, an olefin compound, a vinyl ether compound, an unsaturated sulfone compound, and a (meth)acrylamide 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 step of applying a coating liquid containing the polyvinyl alcohol-based resin on a base film, a step of uniaxially stretching the obtained laminated film, a 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 may form a protective layer on the one side or both surfaces, and may use it as a linear polarizing plate. 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; polyester-based resin films made of resins 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, and still more preferably 30 µm or less from the viewpoint of reducing the thickness of the thermoplastic resin film. , and is usually 5 µm or more, preferably 10 µm 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.

(2) 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 photopolymerizable reactive group refers to a group capable of participating in a polymerization reaction by active radicals or acids generated from the 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. have. 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 the polymerizable liquid crystal compound is not particularly limited, and a rod-shaped liquid crystal compound, a disk-shaped liquid crystal compound, and a mixture thereof can be used. The liquid crystallinity of the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, 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 containing a polymerizable liquid crystal compound and a dichroic dye, and a method for producing 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. 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 other than a polymeric liquid crystal compound and a dichroic dye. 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 use as a linear polarizing plate, without peeling and removing a base film, 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 or may not have an alignment film. 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.

(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 in which a polymerizable liquid crystal compound is cured. 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.

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 polymeric liquid crystal compound to a base film. You may provide an orientation layer 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 from the layer formed by hardening|curing a polymeric liquid crystal compound, the retardation layer may be contained in the optical laminated body in the form which has an orientation layer and a base film. A phase difference layer can be bonded together via the bonding layer mentioned later on the surface on the opposite side to the visual recognition side of a linear polarizing plate.

[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.

Composition and blending 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-curable or thermosetting type, etc.), additives that can be blended into the pressure-sensitive adhesive composition, production of the second pressure-sensitive adhesive layer The method, the thickness of the second pressure-sensitive adhesive layer, and the like 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, compounding component, thickness, and the like of the pressure-sensitive adhesive composition.

[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 the 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 adhesive, a silicone adhesive, a rubber adhesive, a urethane adhesive, a polyester adhesive, an epoxy adhesive. A copolymer adhesive or the like can also be used.

As an adhesive agent used as the material of a bonding layer, it can form combining 1 type, or 2 or more types among a water-system adhesive agent, an active energy ray hardening-type adhesive agent, etc., for example. Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution and a water-based two-component urethane-based emulsion adhesive. An 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 As said polymeric compound, photopolymerizable monomers, such as a photocurable epoxy type monomer, a photocurable acrylic type monomer, and a photocurable urethane type monomer, and the oligomer derived from these monomers, etc. are mentioned. As said photoinitiator, the compound containing the substance which irradiates active energy rays, such as an ultraviolet-ray, and generate|occur|produces active species, such as a neutral radical, an anion radical, 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 a bonding layer may perform a prior corona treatment, a plasma treatment, a flame treatment, etc., and may have a primer layer etc.

[Backboard]

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.

As a plate-shaped object used for the back plate 105, it may be comprised with only one layer, and may be comprised with two or more layers. As the back plate 105, the plate-shaped body illustrated in the front plate 101 can be used.

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

(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 opposed to each other, an insulating spacer sandwiched between the pair of substrates, a transparent conductive film provided as a resistive film on the entire inner surface of each substrate, and a touch position The member comprised by the 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 detection 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 whole 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 the touch sensor panel may be, for example, 5 µm or more and 2000 µm or less, preferably 5 µm or more and 100 µm or less, more preferably 5 µm or more and 50 µm or less, and may be 5 µm or more and 20 µm 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 transcribe|transferred by the to-be-adhered body from a base film through an adhesive layer. That is, the touch sensor panel does not need to have a base film. The thickness of the touch sensor pattern may be, for example, 1 µm or more and 20 µm or less.

[Method for producing optical laminate]

The optical laminated body 100 can be manufactured according to the method including the process of bonding the layers which comprise the optical laminated body 100 through an adhesive layer. When bonding layers together 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 a corona treatment can be set suitably, and conditions may differ from one surface of a bonding surface and another 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 100 of the present invention is excellent in bending durability 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 included in 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.

As an image display element which an image display device has, an organic electroluminescent display element, an inorganic electroluminescent display element, a liquid crystal display element, a plasma display element, a field emission type display element etc. are mentioned, for example.

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.

[How to measure]

The measuring method and calculation method of each physical property value (thickness of a layer, the property of an adhesive layer) used for this Example are as follows.

<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).

<Shear recovery rate>

The shear recovery rate was measured using a viscoelasticity measuring apparatus (MCR-301, manufactured by Anton Paar). The pressure-sensitive adhesive sheet was cut to have a width of 20 mm x length 20 mm, the release film was removed, and 8 pressure-sensitive adhesive layers having a thickness of 25 µm were laminated to form a reference pressure-sensitive adhesive layer having a thickness of 200 µm, which was bonded to a glass plate. Measure under conditions of normal force 1N and torque of 1200 μNm at a temperature of 25°C with the measurement tip attached to it, measure the amount of shear deformation at 1200 seconds, change to the condition of torque 0 μNm, continue the measurement, and continue the measurement at 1206 seconds. The amount of shear strain was measured. Based on these measured values, the shear recovery rate R was calculated from the following formula.

R = ｛ (1200 sec shear strain -1206 sec shear strain) 　/　 1200 sec shear strain ｝ x 100 [%]

<Strain cyclic load test>

As an acceleration test, the strain cyclic load test was performed using the viscoelasticity measuring apparatus (MCR-301, Anton Paar company). The pressure-sensitive adhesive sheet was cut to have a width of 20 mm x length 20 mm, the release film was removed, and 8 pressure-sensitive adhesive layers having a thickness of 25 µm were laminated to form a reference pressure-sensitive adhesive layer having a thickness of 200 µm, which was bonded to a glass plate. With respect to the reference pressure-sensitive adhesive layer on the glass plate, under the conditions of a temperature of 25° C., Normal Force Free, and a frequency of 2 Hz in the state of being adhered to the measuring tip in the device, 0% and 1000% strain loads were applied in 1000 seconds. was repeated throughout.

[Production of pressure-sensitive adhesive sheet containing pressure-sensitive adhesive layer]

In a 1 L reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer, and a stirrer, in the amounts shown in Table 1, 2-ethylhexyl acrylate (2-EHA), butyl acrylate (BA), β-carboxyethyl acrylate (B -CEA), acrylic acid (AA), glycidyl methacrylate (GMA), and a monomer mixture solution of 2-hydroxyethyl methacrylate (2-HEMA) were introduced. Nitrogen gas was refluxed for 1 hour to remove oxygen in the vessel, and the internal temperature was maintained at 60°C. After uniformly mixing the monomer mixture solution, 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 A6.

The obtained (meth)acrylic polymers A1 to A6, 3,3,5-trimethylcyclohexyl acrylic acid (Miramer M1130), lauryl acrylate (Miramer M120), 2-phenoxyethyl acrylate (Miramer M140), and 1-hydroxycyclo Hexylphenyl ketone (I-184) was mixed in the compounding quantity shown in Table 2, and adhesive composition B1-B8 was manufactured.

The pressure-sensitive adhesive compositions B1 to B8 were applied on a release film A (polyethylene terephthalate film, 38 µm thick) coated with a silicone release agent to a thickness of 25 µm. The release 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 release film A/adhesive layer/peelable 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 compounds in Tables 1 and 2 are as follows.

2-EHA: Tokyo Chemical Industry Co., Ltd., Japan

BA: Tokyo Chemical Industry Co., Ltd., Japan

B-CEA: Sigma-Aldrich, USA

AA：Tokyo Chemical Industry Co., Ltd., Japan

GMA: Sigma-Aldrich, USA

2-HEMA: Tokyo Chemical Industry Co., Ltd., Japan

I-651: BASF, Germany

I-184: BASF, Germany

Miramer　M1130：Miwon　specialty　chemical, Korea

Miramer　M120：Miwon　specialty　chemical, Korea

Miramer　M140：Miwon　specialty　chemical, Korea

[Front panel]

As the front plate 101, a film (50 µm) in which a hard coat layer was formed on one side of the resin film was prepared. The resin film was a 40-micrometer-thick polyimide 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 acryl group at the terminal.

[Polarizer layer]

1) As a base film, a triacetyl cellulose (TAC) film (KC2UA, manufactured by Konica Minolta, Inc., thickness 25 μm) was prepared.

2) A solution obtained by dissolving Polymer 1 shown below in cyclopentanone at a concentration of 5% by mass was prepared as a composition for forming an alignment layer. Polymer 1 consists of the following structural units, and has a photoreactive group.

3) A composition for forming a polarizer layer was prepared.

First, 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 a polymerizable liquid crystal compound represented by Formula (1-2) [hereinafter referred to as Compound (1)) -2)] was prepared.

Compound (1-1) and compound (1-2) were synthesized according to the method described in Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996).

As a dichroic dye, the azo dye described in the Example of Unexamined-Japanese-Patent No. 2013-101328 represented by following formula (2-1a), (2-1b), (2-3a) was prepared.

The composition for polarizer layer formation is 75 mass parts for compound (1-1), 25 mass parts for compound (1-2), and said formula (2-1a), (2-1b), ( 2.5 parts by mass each of the azo dye represented by 2-3a) and 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure369, manufactured by BASF Japan) as a polymerization initiator 6 mass parts and 1.2 mass parts of polyacrylate compound (BYK-361N, BYK-Chemie company make) as a leveling agent are mixed with 400 mass parts of toluene of a solvent, and it prepares by stirring the obtained mixture at 80 degreeC for 1 hour. did.

4) Composition for forming a protective layer

The composition for forming a protective layer contains 100 parts by mass of water, 3 parts by mass of polyvinyl alcohol resin powder (manufactured by Kuraray Co., Ltd., average degree of polymerization 18000, trade name: KL-318), and a polyamide epoxy resin (crosslinking agent, It was prepared by mixing 1.5 mass parts of Sumika Chemtex co., Ltd. make, brand name:SR650(30)).

5) The polarizer layer was produced by the procedure shown next.

First, corona treatment was performed once to the TAC film side of a base film. Conditions for corona treatment were an output of 0.3 kW and a processing speed of 3 m/min. Then, on the said TAC film, the composition for alignment film formation was apply|coated according to the bar-coat method, and it heat-dried in 80 degreeC drying oven for 1 minute. The obtained dry film was subjected to polarization UV irradiation treatment to form a first alignment film AL1. Polarized UV treatment is performed by transmitting light irradiated from a UV irradiation device (SPOT CURE SP-7; manufactured by USHIO INC.) through a wire grid (UIS-27132 # #, manufactured by USHIO INC.) and measuring at a wavelength of 365 nm. It carried out on condition that the amount of accumulated light is 100 mJ/cm<2>. The thickness of the first alignment layer was 100 nm.

Then, on the 1st alignment film, the composition for polarizer layer formation was apply|coated according to the bar-coat method, after heating and drying for 1 minute in 120 degreeC drying oven, it cooled to room temperature. A polarizer layer was formed by irradiating the dried film with ultraviolet rays at an accumulated light amount of 1200 mJ/cm 2 (based on 365 nm) using the above UV irradiation device. The thickness of the obtained polarizer layer was 1.8 micrometers.

6) On the polarizer layer, the composition for forming a protective layer was coated according to the bar coating method so that the thickness after drying might be set to 1.0 µm, and dried at a temperature of 80°C for 3 minutes. Thus, the linear polarizing plate which consists of "base film/polarizer layer/overcoat layer)" was obtained.

[phase difference layer]

1) A polyethylene terephthalate (PET) film having a thickness of 100 μm was prepared as a base film.

2) The composition for forming an alignment layer was the same as the composition for forming an alignment layer.

3) Each component shown below was mixed, and the composition for phase difference layer formation was obtained by stirring the obtained mixture at 80 degreeC for 1 hour.

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 (Irgacure369, 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one, manufactured by BASF Japan): 6 parts by mass

Leveling agent (BYK-361N, polyacrylate compound, BYK-Chemie company make): 0.1 mass part

Solvent (cyclopentanone): 400 parts by mass.

4) The retardation layer was produced by the procedure shown below.

First, a composition for forming an alignment film was applied to a base film according to a bar coating method, and dried by heating in a drying oven at 80°C for 1 minute. The obtained dry film was subjected to polarization UV irradiation treatment to form a second alignment film. Polarization UV treatment was performed under the condition that the amount of accumulated light measured at a wavelength of 365 nm was 100 mJ/cm 2 using the above UV irradiation device. The polarization direction of polarization UV was performed so that it might become 45 degrees with respect to the absorption axis of a polarizer layer.

5) Then, on the 2nd alignment film, the composition for phase difference layer formation was apply|coated according to the bar-coating method, after heating and drying for 1 minute in 120 degreeC drying oven, it cooled to room temperature. A retardation layer was formed by irradiating the obtained dry film with ultraviolet rays with an accumulated light amount of 1000 mJ/cm 2 (based on 365 nm) using the above UV irradiation device. The thickness of the obtained retardation layer was 2.0 micrometers. The retardation layer was a λ/4 plate showing a retardation value of λ/4 in the in-plane direction. In this way, the retardation layer which consists of "base film/λ/4 retardation layer" was obtained.

[Attached sheet]

An acrylic resin was obtained by making the following component react at 55 degreeC, stirring in nitrogen atmosphere.

Butyl acrylate: 70 parts by mass

Methyl acrylate: 20 parts by mass

Acrylic acid: 2.0 parts by mass

Radical polymerization initiator (2,2'-azobisisobutyronitrile): 0.2 mass part.

Then, the following components were mixed and the composition for bonding layers was obtained.

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" by Shin-Etsu Chemical Co., Ltd.): 0.5 mass part.

The obtained composition for bonding layers was prepared by adding ethyl acetate so that total solid content concentration might be 10 mass %.

The coating layer was obtained by apply|coating the crude composition for bonding layers so that the thickness after drying might be set to 5 micrometers using an applicator on the release-processed peeling film A (polyethylene terephthalate film, 38 micrometers in thickness). This application layer was dried at 100 degreeC for 1 minute, and the film provided with a bonding layer was obtained. Then, on the exposed surface of the bonding layer, the release-processed peeling film B (a polyethylene terephthalate film, 38 micrometers in thickness) was bonded together. It was made to cure for 7 days on the conditions of temperature 23 degreeC and 50 %RH of relative humidity, and the bonding sheet|seat which has the layered structure of peeling film A/bonding layer / peeling film B was obtained.

[Backboard]

As the back plate 105 , a touch sensor panel in which a transparent conductive layer, a separation layer, an adhesive layer, and a base layer were laminated in this order was prepared. The transparent conductive layer contained the ITO layer, the separation layer contained the cured layer of the acrylic resin composition, and the total thickness of both was 7 micrometers. The adhesive layer had a thickness of 2 µm. The base material layer was a cycloolefin (COP) film (ZF-14, ZEON CORPORATION (Japan) make, 23 micrometers in thickness).

[Production of optical laminate]

The optical laminates of Examples 1-5 and Comparative Example 1 were manufactured in the order shown to FIG.2(a)-(e). As shown in Table 3, the adhesive sheet which consists of the adhesive composition shown in Table 2 was used as a 1st adhesive layer or a 2nd adhesive layer.

First, the linear polarizing plate 410 (base film 301 / polarizer layer 302 / overcoat layer 303) containing a polarizer layer and the above-mentioned bonding sheet 420 (release film A 304 / bonding layer) 305) / release film B (306)) was prepared (Fig. 2(a)). Corona treatment (output 0.3 KW, speed 3 m/min) was performed on the overcoat layer 303 side of the linear polarizing plate 410 containing the polarizer layer and the surface from which the release film A 304 of the bonding sheet 420 was peeled off Then, it bonded together and obtained the laminated body A (430). Further, a retardation layer 440 (base film 308/λ/4 retardation layer 307) was prepared. (Fig. 2(b)).

After performing corona treatment (output 0.3 KW, speed 3 m/min) on the λ/4 retardation layer 307 side of the retardation layer 440 and the surface from which the release film B 306 of the laminate A 430 was peeled off , and bonded together to obtain a circularly polarizing plate 450 . Moreover, the adhesive sheet produced above was prepared as the adhesive sheet 460 (release film A (309)/adhesive layer 310/release film B (311)) (FIG. 2(c)). The pressure-sensitive adhesive layer 310 of the pressure-sensitive adhesive sheet 460 corresponds to the second pressure-sensitive adhesive layer.

After corona treatment (output 0.3 KW, speed 3 m/min) of the surface from which the base film 308 of the circularly polarizing plate 450 was peeled and the surface from which the peeling film A 309 of the adhesive sheet 460 was peeled, It bonded together, and the laminated body B (470) was obtained. Furthermore, the adhesive sheet produced above was prepared as the adhesive sheet 490 (release film A 314 / adhesive layer 315 / peeling film B 316). Corona treatment (output 0.3 KW, speed 3 m/min. ), it was bonded together and laminated body C (500) was obtained (FIG.2(d)). The pressure-sensitive adhesive layer 315 of the pressure-sensitive adhesive sheet 490 corresponds to the first pressure-sensitive adhesive layer.

After performing corona treatment (output 0.3 KW, speed 3 m/min) on the side which peeled the peeling film B (316) of the laminated body C (500), and the base film 301 side of the laminated body B (470), stick combined to obtain a laminate D (510) (Fig. 2(e)).

Peeling of the transparent electrode layer 317 side of the touch sensor panel 520 on which the transparent conductive layer 317 , the separation layer 318 , the adhesive layer 319 , and the base layer 320 are laminated and the laminate D (510) After corona-treating (output 0.3KW, speed|rate 3 m/min) to the surface which peeled the film B (311), it bonded together and the optical laminated body was obtained.

For the optical laminates of Examples 1 to 5 and Comparative Example 1, the following flexibility test and surface hardness test were performed. A result is shown in Table 3.

<Flexibility evaluation test>

The optical laminates of each Example and each comparative example were folded and bent so that the front plate 101 side was on the inside (bending radius of 1.5 mm), that is, the distance between the opposite front plates was folded so that the distance between the front plates was 3.0 mm, temperature 60 ° C, humidity After leaving it for 24 hours under the condition of 90%RH, it was taken out and left at room temperature for 30 minutes (durability test).

After the end of the durability test, the optical laminated body canceled the bending state. From the optical laminate after the durability test, a test piece having a length of 100 mm and a width of 10 mm was cut using a super cutter so that the bent portion was in the middle. With respect to this test piece, using a bending resistance tester (cylindrical mandrel method) manufactured by TP Giken Co., Ltd., the test piece is wound around a cylindrical shaft (mandrel) so that the front plate of the test piece is inside, and the test piece is lengthened at a temperature of 25°C. A flexibility evaluation test (mandrel test) to bend along the direction was performed.

For this reason, the minimum diameter of the axis|shaft at which bubbles do not generate|occur|produce in the adhesive layer of a test piece was calculated|required, and it ranked based on the following criteria. In a flexibility evaluation test, it can be evaluated that it is excellent in bending durability of an adhesive layer, so that the value of this minimum diameter is small.

A: When it wound on the shaft of diameter (phi) 10 mm or less, the bubble generate|occur|produced in the adhesive layer.

B: When it wound on the shaft of more than phi 10 mm and less than phi 15 mm, the bubble generate|occur|produced in the adhesive layer.

C: When it wound on the shaft of more than phi 15 mm and less than phi 20 mm, bubbles generate|occur|produced in the adhesive layer.

D: When it wound on the axis|shaft of more than phi 20 mm, the bubble generate|occur|produced in the adhesive layer.

<Surface hardness evaluation test>

The optical laminates of each Example and each comparative example were folded and bent so that the front plate 101 side was on the inside (bending radius of 1.5 mm), that is, the distance between the opposite front plates was folded so that the distance between the front plates was 3.0 mm, temperature 60 ° C, humidity After leaving it for 24 hours under the condition of 90%RH, it was taken out and left at room temperature for 30 minutes (durability test).

A 100 g load was applied at a temperature of 25°C using a pencil hardness tester (PHT, manufactured by SUKBO 　SCIENCE (Korea)) on the surface of the front plate 101 side in the bent portion of the optical laminate after the durability test. With a state pencil (manufactured by MITSUBISHI PENCIL CO., LTD., pencil lead hardness 6B), a dent was formed on the surface. Then, the surface hardness of the optical laminated body of each Example and each comparative example was evaluated by measuring the time until the recessed mark disappears, and ranking based on the following criteria. In this surface hardness test, it can be evaluated that it is excellent in surface hardness, so that the time until the recessed part disappears is short.

A: Concave marks disappeared in less than 30 minutes.

B: Concave marks disappeared in 30 minutes or more and less than 60 minutes.

C: Concave marks disappeared in 60 minutes or more and less than 90 minutes.

D: Even if 90 minutes passed, the recessed part did not disappear.

100 Laminate,
101 front panel,
102 first adhesive layer;
103 polarizer,
104 second adhesive layer;
105 backplate.

Claims (7)

A front plate, a first adhesive layer formed using the first adhesive composition, a polarizing plate, a second adhesive layer formed using the second adhesive composition, and a back plate are provided in this order,
In the first reference pressure-sensitive adhesive layer having a thickness of 200 μm formed using the first pressure-sensitive adhesive composition, the shear recovery rate at a temperature of 25° C. before and after the deformation repeated load test is R1A [%] and R1B [%], respectively, and 2 In the second reference pressure-sensitive adhesive layer having a thickness of 200 μm formed using the pressure-sensitive adhesive composition, when the shear recovery rates at a temperature of 25° C. before and after the deformation cyclic load test were R2A [%] and R2B [%], respectively, the following An optical laminate which satisfies the relational expressions (1) and (2).
ΔR1=｛(R1A)-(R1B)｝/200≤0.2 (1)
ΔR2=｛(R2A)-(R2B)｝/200≤0.2 (2) According to claim 1,
The optical laminated body which further satisfy|fills following relational expression (3).
R1A≤R2A (3) 3. The method of claim 1 or 2,
The optical laminate which further satisfies the following relational expression (4).
ΔR1≤ΔR2 (4) 4. The method according to any one of claims 1 to 3,
R 1A [%] is 20% or more, the optical laminate. 5. The method according to any one of claims 1 to 4,
The said back plate is a touch sensor panel, The optical laminated body. A display device comprising the optical laminate according to any one of claims 1 to 5. 7. The method of claim 6,
A display device capable of being bent with the front plate side inside.

Images