TW201910460A - Laminate for flexible image display device and flexible image display device - Google Patents

Abstract

The purpose of the present invention is to provide a laminate for a flexible image display device in which as a result of using an optical film, which includes at least a polarizing film, and a pressure-sensitive adhesive layer having a specific modulus, excellent bending resistance and adhesion are demonstrated without the occurrence of peeling or cracking in repeated bending at ordinary temperature and even under a high-temperature environment, and also to provide a flexible image display device on which the laminate for a flexible image display device is arranged. The laminate for a flexible image display device including a pressure-sensitive adhesive layer and an optical film including at least a polarizing film is characterized in that a stress at a 100% modulus of the pressure-sensitive adhesive layer is 0.01-0.1 N/mm2, and that a stress at a 500% modulus of the pressure-sensitive adhesive layer is 0.05-0.2 N/mm2.

Description

Multilayer body and flexible image display device for flexible image display device

The present invention relates to a laminated body for a flexible image display device and a flexible image display device in which the laminated body for the flexible image display device is disposed, and the laminated body for the flexible image display device includes an optical film including at least a polarizing film and Specific adhesive layer.

BACKGROUND OF THE INVENTION An organic EL display device of a touch sensor integrated type is provided with an optical layered body 20 on the viewing side of the organic EL display panel 10, and is provided on the viewing side of the optical layered body 20, as shown in FIG. Control panel 30. The optical laminate 20 includes a polarizing film 1 having protective films 2-1 and 2-2 bonded to both surfaces thereof, and a retardation film 3, and a polarizing film 1 is provided on the viewing side of the retardation film 3. Further, the touch panel 30 has a structure in which the transparent conductive films 4-1 and 4-2 are disposed via the spacer 7, and the transparent conductive films 4-1 and 4-2 have the substrate films 5-1 and 5-2 and The transparent conductive layers 6-1 and 6-2 are laminated (see, for example, Patent Document 1).

Further, it is expected to realize an organic EL display device which is more excellent in portability and bendable.

PRIOR ART DOCUMENT PATENT DOCUMENT Patent Document 1: Japanese Laid-Open Patent Publication No. 2014-157745

Disclosure of the Invention Problems to be Solved by the Invention However, the conventional organic EL display device disclosed in Patent Document 1 is not designed in consideration of the bending function. As long as the plastic film is used for the organic EL display panel substrate, the flexibility of the organic EL display panel can be imparted. When the plastic film is used for a touch panel and incorporated into an organic EL display panel, the flexibility of the organic EL display panel can still be imparted. However, there is a problem that the optical film including the conventional polarizing film or the like laminated on the organic EL display panel hinders the flexibility of the organic EL display device.

In addition, when the organic EL display device is repeatedly bent at a normal temperature, slight strain, peeling, or cracking (breakage) occurs between layers or layers of an optical film and an adhesive layer constituting the organic EL display device. The problem arises. Further, in addition to the problem at room temperature, when the bending is performed in a high-temperature environment, the adhesive layer may be cohesively broken and the peeling tends to be remarkable.

Therefore, an object of the present invention is to provide a laminate for a flexible image display device and a flexible image display device in which the laminate for the flexible image display device is disposed, and the laminate for the flexible image display device is used. An optical film containing at least a polarizing film and an adhesive layer having a specific modulus will not face the reverse deflection even when exposed to normal temperature (for example, 25 ° C × 50% RH) or a high temperature environment (for example, 70 ° C). Exfoliation and cracking occur, resulting in excellent flex resistance and adhesion.

Means for Solving the Problem The laminated body for a flexible image display device of the present invention is characterized in that it comprises an adhesive layer and an optical film containing at least a polarizing film, and the stress of the 100% modulus of the adhesive layer is 0.01 to 0.1 N/mm ² , and the stress of the 500% modulus of the aforementioned adhesive layer is 0.05 to 0.2 N/mm ² . Further, "100% modulus stress" means stress at 100% elongation (Strain). The other 500% and 700% modulus are also synonymous.

The laminate for a flexible image display device of the present invention preferably has a gel fraction of 55 to 90% by weight of the adhesive layer.

The laminated body for a flexible image display device of the present invention preferably has two or more layers and five or less layers of the above-mentioned adhesive layer.

The laminated body for a flexible image display device of the present invention preferably has a stress of 100% modulus of the adhesive layer of 0.01 to 0.08 N/mm ² .

The laminated body for a flexible image display device of the present invention preferably has a stress of 500% modulus of the adhesive layer of 0.085 to 0.2 N/mm ² .

In the flexible image display device of the present invention, the laminated body for the flexible image display device and the organic EL display panel are disposed, and the laminated body for the flexible image display device is disposed on the viewing side of the organic EL display panel.

In the flexible video display device of the present invention, it is preferable that a window is disposed on the viewing side of the laminated body for the flexible video display device.

According to the present invention, it is useful to obtain a laminate for a flexible image display device and to obtain a flexible image display device in which the laminate for the flexible image display device is disposed, which is useful; the flexible image display device By using an optical film containing at least a polarizing film and an adhesive layer having a specific modulus, even if it is exposed to a normal temperature (for example, 25 ° C × 50% RH) or a high temperature environment (for example, 70 ° C), the surface is faced. The reverse deflection does not peel or break, and thus has excellent flex resistance and adhesion.

In the following, an embodiment of the optical film and the flexible image display device laminate and the flexible image display device of the present invention will be described in detail with reference to the drawings and the like.

The present invention is not limited by the following embodiments, and may be modified and carried out without departing from the spirit and scope of the invention.

[Laminate for Flexible Image Display Device] The laminate for a flexible image display device of the present invention is characterized by comprising an adhesive layer and an optical film.

[Optical film] The laminated body for a flexible image display device of the present invention is characterized by comprising an optical film containing at least a polarizing film, and the optical film further comprises a protective film formed of, for example, a transparent resin material, in addition to the polarizing film. A film such as a retardation film. In the present invention, the optical film includes the polarizing film, a protective film of a transparent resin material on the first surface of the polarizing film, and the polarizing film and the first layer. A retardation film which is provided on the second surface of the first surface. Further, the optical film does not include an adhesive layer such as a first adhesive layer described later.

The thickness of the optical film is preferably 92 μm or less, more preferably 60 μm or less, and still more preferably 10 to 50 μm. If it is within the above range, it will be preferable without hindering the deflection.

A protective film (not shown in the drawings) may be bonded to at least one side of the polarizing film by passing an adhesive (layer) as long as the characteristics of the present invention are not impaired. An adhesive can be used for the subsequent treatment of the polarizing film and the protective film. Examples of the adhesive agent include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, and an aqueous polyester. The above-mentioned adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of a solid component. In addition to the above, examples of the adhesive agent for the polarizing film and the protective film include an ultraviolet curable adhesive, an electron beam curable adhesive, and the like. The adhesive for an electron beam hardening type polarizing film exhibits good adhesion to the above various protective films. Further, the adhesive used in the present invention may contain a metal compound filler. Further, in the present invention, a polarizing film (polarizing plate) may be referred to as a polarizing film and a protective film by bonding an adhesive (layer).

<Polarizing film> A polarizing film (also referred to as a polarizing member) contained in the optical film of the present invention may be a polyvinyl alcohol (PVA) resin, and the polyvinyl alcohol (PVA) resin is extended in the air (dry stretching) Or an extension step such as an extension step of boric acid water, and the iodine has been oriented.

The method for producing a polarizing film is a method (single layer stretching method) described in JP-A-2004-341515, which comprises a step of dyeing a single layer of a PVA resin and a step of stretching. In addition, Japanese Laid-Open Patent Publication No. H05-069644, JP-A-2000-338329, JP-A-2001-343521, International Publication No. 2010/100917, and JP-A-2012-073563 Japanese Laid-Open Patent Publication No. 2011-2816, which comprises a step of stretching a PVA-based resin layer and a resin substrate for stretching in a state of being laminated, and a step of performing dyeing. According to this production method, even if the PVA-based resin layer is thin, since it is supported by the resin substrate for stretching, it can be stretched without causing defects such as breakage due to stretching.

In the method of the step of performing the step of stretching in the state of the layered body and the step of performing the dyeing, the above-mentioned Japanese Patent Laid-Open Publication No. Sho 51-069644, JP-A-2000-338329, and JP-A-2001-343521 The air extension (dry extension) method described. In addition, it is preferable to carry out the step of extending in a boric acid aqueous solution as described in Japanese Laid-Open Patent Publication No. 2010-073563, and the method of extending the polarizing performance. In particular, a method (two-stage extension method) including a step of performing air-assisted extension before stretching in an aqueous solution of boric acid is preferred as disclosed in Japanese Laid-Open Patent Publication No. 2012-073563. In addition, it is also preferable to produce a PVA-based resin layer and a resin substrate for stretching in a state of being laminated, and then PVA is used in the production method described in JP-A-2011-2816. The resin layer was excessively dyed, and then it was decolorized. The polarizing film contained in the optical film of the present invention can be formed into a polarizing film consisting of a polyvinyl alcohol-based resin which has been oriented with iodine as described above, and which is extended by a stretch of air and a stretch of boric acid in water. The steps are extended. Further, the polarizing film may be formed of a polarizing film which is composed of a polyvinyl alcohol-based resin which has been oriented with iodine as described above, and which excessively dyes the layered body of the stretched PVA-based resin layer and the extending resin substrate. It is then made by discoloring it.

The thickness of the polarizing film is 20 μm or less, preferably 12 μm or less, preferably 9 μm or less, more preferably 1 to 8 μm, and particularly preferably 3 to 6 μm. If it is within the above range, it will be preferable without hindering the deflection.

<Retardation film> The optical film used in the present invention may include a retardation film, and the retardation film (also referred to as a retardation film) may be obtained by stretching or fixing the polymer film. The person. In the present specification, the retardation film means a person having birefringence in the in-plane and/or thickness direction.

The retardation film is, for example, a retardation film for antireflection (refer to JP-A-2012-133303, [0221], [0222], [0228]), and a retardation film for viewing angle compensation (refer to JP-A-2012-133303). Bulletin [0225], [0226], and an oblique alignment retardation film for viewing angle compensation (refer to Japanese Laid-Open Patent Publication No. 2012-133303 (0227)).

The retardation film is not particularly limited as long as it has substantially the above-described functions, for example, a phase difference value, an arrangement angle, a three-dimensional birefringence, a single layer or a plurality of layers, and a known retardation film can be used.

The thickness of the retardation film is preferably 20 μm or less, preferably 10 μm or less, more preferably 1 to 9 μm, and particularly preferably 3 to 8 μm. If it is within the above range, it will be preferable without hindering the deflection.

<Protective film> The optical film used in the present invention may include a protective film formed of a transparent resin material, and the protective film (also referred to as a transparent protective film) may be a cycloolefin-based resin such as a norbornene-based resin. An olefin resin such as ethylene or polypropylene, a polyester resin, or a (meth)acrylic resin.

The thickness of the protective film is preferably 5 to 60 μm, more preferably 10 to 40 μm, more preferably 10 to 30 μm, and a surface treatment layer such as an antiglare layer and an antireflection layer may be appropriately provided. If it is within the above range, it will be preferable without hindering the deflection.

[Adhesive Layer] The laminated body for a flexible image display device of the present invention is characterized in that it contains an adhesive layer, and the stress of the 100% modulus of the adhesive layer is 0.01 to 0.1 N/mm ² , and the adhesion is as described above. The stress of the 500% modulus of the agent layer is 0.05 to 0.2 N/mm ² . By adjusting the stress of the 100% modulus of the adhesive layer and the stress of 500% modulus to a specific range, a laminate for a flexible image display device and a laminate for the flexible image display device can be obtained. The flexible image display device of the flexible image display device does not occur in the face of repeated deflection even when exposed to normal temperature (for example, 25 ° C × 50% RH) or high temperature (for example, 70 ° C). Exfoliation and cracking, resulting in excellent flex resistance and adhesion.

Further, the pressure-sensitive adhesive layer may be one layer, and may have two or more layers in addition to the optical film, for example, in order to laminate a transparent conductive film, an organic EL display panel, a window, a decorative printed film, a retardation layer, a protective film, or the like (for example, When the multilayer adhesive layer such as the first adhesive layer and the second adhesive layer is used in the laminate for a video display device, for example, see FIG. 2 and the like. When having a multilayer adhesive layer, it is preferable to have 2 or more layers and 5 or less layers. When the number is more than 5 layers, the thickness of the entire laminated body is increased, and the strain difference between the outermost layer and the innermost layer of the bent portion of the laminated body is increased, and peeling or cracking is likely to occur, which is not preferable.

[First Adhesive Layer] Among the adhesive layers used in the laminate for a flexible image display device of the present invention, it is preferable that the first adhesive layer is disposed on the surface of the protective film that is in contact with the polarizing film. The opposite side (see Figure 2).

The adhesive layer of the first adhesive layer used for the laminate for the flexible image display device of the present invention may be an acrylic adhesive, a rubber adhesive, a vinyl alkyl ether adhesive, or a polyoxygen adhesive. A polyester-based adhesive, a polyamide-based adhesive, an urethane-based adhesive, a fluorine-based adhesive, an epoxy-based adhesive, or a polyether-based adhesive. Further, the adhesive constituting the above-mentioned adhesive layer may be used singly or in combination of two or more kinds. However, it is preferable to use an acrylic pressure-sensitive adhesive (composition) containing a (meth)acrylic polymer alone from the viewpoints of transparency, workability, durability, adhesion, and flex resistance.

<(Meth)acrylic polymer> When an acrylic adhesive is used as the adhesive composition, it is preferred to contain (meth)acrylic acid having a linear or branched alkyl group having 1 to 30 carbon atoms. A (meth)acrylic polymer having a monomer as a monomer unit. By using the (meth)acrylic monomer having a linear or branched alkyl group having 1 to 30 carbon atoms, an adhesive layer having excellent flexibility can be obtained. Further, the (meth)acrylic polymer in the present invention means an acrylic polymer and/or a methacrylic polymer, and the methacrylate means an acrylate and/or a methacrylate.

Specific examples of the (meth)acrylic monomer having a linear or branched alkyl group having 1 to 30 carbon atoms which constitutes the main skeleton of the (meth)acrylic polymer include (methyl) ) methyl acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, secondary butyl (meth) acrylate, tertiary butyl (meth) acrylate, isobutyl (meth) acrylate , n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, (meth)acrylic acid 2 -ethylhexyl ester, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-decyl (meth)acrylate , isodecyl (meth)acrylate, n-dodecyl (meth)acrylate (lauryl (meth)acrylate), n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, etc. From the viewpoint of flexibility, a (meth)acrylic monomer having a linear or branched alkyl group having 6 to 30 carbon atoms (hereinafter sometimes referred to as "having a long-chain alkyl group" (meth)acrylic single ") Preferably, (meth) acrylate, n-dodecyl acrylate ((meth) acrylate, lauryl) better. By using the above-mentioned (meth)acrylic monomer having a long-chain alkyl group, the entanglement of the polymer can be reduced to make it easy to undergo slight strain deformation, which is preferable for flexibility. Further, from the viewpoint of flexibility and adhesion at a low temperature, it is preferred to use a (meth)acrylic monomer having a glass transition temperature (Tg) of a homopolymer of -70 to -20 ° C, wherein It is more preferred to use 2-ethylhexyl acrylate. Further, one type or two or more types of the above (meth)acrylic monomers may be used. In addition, the "small strain" is expressed in the laminated body for a flexible image display device, for example, a strain of about 0 to 10% in a bending direction of 3 mm around the apex of the flexure, and "+" means stretching. The strain in the direction, "-" indicates the strain in the direction of compression. In general, the outer side of the bend (the convex side) has a strain increase in the tensile direction of "+", and the inner side of the bend (the concave side) has a strain increase in the compression direction of "-", and the layered body to be deflected is There is a strain stress at 0 anywhere in the interior where the vertical axis exists.

The (meth)acrylic monosystem having a linear or branched alkyl group having 1 to 30 carbon atoms constitutes a main component of the total monomer of the (meth)acrylic polymer. Here, the main component means a (meth)acrylic monomer having a linear or branched alkyl group having 1 to 30 carbon atoms in the total monomer constituting the (meth)acrylic polymer. It is preferably 50 to 100% by weight, more preferably 80 to 100% by weight, and more preferably 90 to 99.9% by weight, particularly preferably 94 to 99.9.

The monomer component constituting the (meth)acrylic polymer may contain a copolymerizable (meth)acrylic monomer having a linear or branched alkyl group having 1 to 30 carbon atoms. Monomer (copolymerizable monomer). Further, the copolymerizable monomers may be used singly or in combination of two or more.

The copolymerizable monomer is not particularly limited, and is preferably a (meth)acrylic polymer containing a hydroxyl group-containing monomer having a reactive functional group. An adhesive layer excellent in adhesion and flexibility can be obtained by using the above-mentioned hydroxyl group-containing monomer. The hydroxyl group-containing single system is a compound containing a hydroxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group.

Specific examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and (meth)acrylic acid 6- Hydroxyhexyl ester, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, hydroxyalkyl (meth)acrylate such as 12-hydroxylauryl (meth)acrylate or (4) -Hydroxymethylcyclohexyl)-methacrylate or the like. From the viewpoint of durability and adhesion, the hydroxyl group-containing monomer is preferably 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate. Further, one type or two or more types of the hydroxyl group-containing monomers may be used.

Further, the copolymerizable monomer may contain a monomer such as a carboxyl group-containing monomer having a reactive functional group, an amine group-containing monomer, and a guanamine group-containing monomer. It is preferred to use these monomers from the viewpoint of humidification and adhesion in a high temperature environment.

When an acrylic adhesive is used as the adhesive composition, a (meth)acrylic polymer containing a carboxyl group-containing monomer having a reactive functional group as a monomer unit may be contained. By using the above-mentioned carboxyl group-containing monomer, an adhesive layer excellent in adhesion in a humidified environment and a high temperature environment can be obtained. The carboxyl group-containing single system is a compound containing a carboxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group.

Specific examples of the carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and the like.

When an acrylic adhesive is used as the above-mentioned adhesive composition, a (meth)acrylic polymer containing a monomer having an amino group having a reactive functional group as a monomer unit may be contained. By using the above-mentioned amine group-containing monomer, an adhesive layer excellent in adhesion in a humidified and high-temperature environment can be obtained. The above-mentioned amine group-containing single system is a compound containing an amine group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acrylonitrile group or a vinyl group.

Specific examples of the amino group-containing monomer include N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

When an acrylic adhesive is used as the above-mentioned adhesive composition, a (meth)acrylic polymer containing a guanamine group-containing monomer having a reactive functional group as a monomer unit may be contained. By using a monomer containing the aforementioned mercapto group, an adhesive layer excellent in adhesion can be obtained, and in particular, the following adhesive layer can be obtained: not only at normal temperature (for example, 25 ° C × 50% RH) or high temperature environment Lower (for example, 70 ° C), even under harsh conditions (such as 85 ° C) or high temperature, high humidity environment (such as 65 ° C × 95% RH) and other harsh conditions, it also has excellent density The above-mentioned monoamine-containing mono-system is a compound containing a mercaptoamine group in its structure and containing a polymerizable unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group.

Specific examples of the above-mentioned mercapto group-containing monomer include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, and N,N-diethyl(meth)acrylamide. , N-isopropyl acrylamide, N-methyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methylol (Meth) acrylamide, N-methylol-N-propane (meth) acrylamide, amine methyl (meth) acrylamide, amine ethyl (meth) acrylamide, hydrazine methyl Acrylamide monomer such as (meth)acrylamide or decylethyl(meth)acrylamide; N-(methyl)propenyl carbaryl, N-(methyl)propenylpiperidine N-propylene fluorenyl heterocyclic monomer such as N-(methyl) propylene decyl pyrrolidine; N-vinyl fluorene containing N-vinyl pyrrolidone, N-vinyl-ε-caprolactam, etc. An amine-based monomer or the like is preferable, and among them, an N-vinylnamidamide-based monomer is preferred.

Further, the comonomer may be a polyfunctional monomer (polyfunctional monomer). If a polyfunctional monomer is contained, a crosslinking effect can be obtained by polymerization, and the gel fraction can be easily adjusted and the cohesive force can be improved. Therefore, the cutting becomes easy, and the workability is easily improved. Moreover, during deflection (especially in a high temperature environment), peeling due to cohesive failure of the adhesive layer can be prevented. The polyfunctional monomer is not particularly limited, and examples thereof include hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate) and butanediol di(meth)acrylate. (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, Neopentyl triol (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, a polyfunctional acrylate such as allyl (meth) acrylate, vinyl (meth) acrylate, epoxy acrylate, polyester acrylate or urethane acrylate, or divinyl benzene, etc., as polyfunctional acrylic acid The ester is preferably 1,6-hexanediol diacrylate or dipentaerythritol hexa(meth)acrylate. Further, the polyfunctional monomer may be used singly or in combination of two or more.

The monomer unit constituting the (meth)acrylic polymer, the blending ratio (total amount) of the monomer having a reactive functional group and the polyfunctional monomer is constituting the (meth)acrylic polymer. The total monomer is preferably 20% by weight or less, more preferably 10% by weight or less, still more preferably 0.01 to 8% by weight, particularly preferably 0.01 to 5% by weight, most preferably 0.05 to 3% by weight. When it exceeds 20% by weight, the crosslinking point will increase and the adhesive (layer) will lose flexibility, so that the stress relaxation property tends to be poor.

When an acrylic adhesive is used as the adhesive composition, the monomer unit may be a monomer unit and a polyfunctional monomer having a reactive functional group as long as the effect of the present invention is not impaired. Introduce other comonomers.

Further, the other comonomer may, for example, be an alkoxyalkyl (meth)acrylate [e.g. 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, (A) Base) methoxytriethylene glycol acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, (A) Ethyl 4-butyl acrylate, etc.; an epoxy group-containing monomer [eg, glycidyl (meth) acrylate, methyl methacrylate (meth) acrylate, etc.]; Monomer [eg, sodium vinyl sulfonate, etc.]; phosphate group-containing monomer; (meth) acrylate having an alicyclic hydrocarbon group [eg, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate) , (Isodecyl (meth) acrylate, etc.); (meth) acrylate having an aromatic hydrocarbon group [eg, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate) Ethylene esters [eg vinyl acetate, vinyl propionate, etc.]; aromatic vinyl compounds [eg styrene, vinyl toluene, etc.]; olefins or dienes [eg ethylene, propylene, butadiene] Isoprene, Butene, etc.]; vinyl ethers [such as vinyl alkyl ethers]; chloride and the like.

The blending ratio of the other comonomer is not particularly limited, but is preferably 30% by weight or less, more preferably 10% by weight or less, and is not contained in the total monomer constituting the (meth)acrylic polymer. good. When it exceeds 30% by weight, in particular, when a (meth)acrylic monomer is used, the reaction point between the adhesive layer and other layers (thin film or substrate) is reduced, and the adhesion tends to be lowered.

The adhesive layer is formed of an adhesive composition, and the adhesive composition may be an adhesive composition having any form, and examples thereof include an emulsion type, a solvent type (solution type), and an active energy ray-hardening type. Hot melt type (hot melt type) and the like. Among these, the above-mentioned adhesive composition is preferably a solvent-based adhesive composition or an active energy ray-curable adhesive composition.

The solvent-based adhesive composition preferably contains an adhesive composition containing the (meth)acryl-based polymer as an essential component. In addition, the active energy ray-curable adhesive composition preferably contains an adhesive (monomer mixture) constituting the monomer component of the (meth)acrylic polymer or a partial polymer thereof as an essential component. Composition. In addition, the "partial polymer" means a composition in which one or two or more of the monomer components contained in the monomer mixture are partially polymerized. Further, the "monomer mixture" is defined as a case where only one monomer component is contained.

The above-mentioned adhesive composition is preferably contained in a monomer composition constituting the (meth)acrylic polymer from the viewpoint of productivity, the viewpoint of environmental influence, and the ease of obtaining the adhesive layer having a thickness. An active energy ray-curable adhesive composition in which a mixture (monomer mixture) or a partial polymer thereof is an essential component.

The (meth)acrylic polymer can be obtained by polymerizing the above monomer component. More specifically, the monomer component, the above monomer mixture or a partial polymer thereof can be obtained by polymerization in a known manner. Examples of the polymerization method include solution polymerization, emulsion polymerization, bulk polymerization, polymerization by thermal or irradiation of an active energy ray (thermal polymerization, active energy ray polymerization), and the like. Among them, from the viewpoints of transparency, water resistance, cost, and the like, solution polymerization and active energy ray polymerization are preferred. Further, from the viewpoint of suppressing polymerization inhibition by oxygen, the polymerization should be avoided by contact with oxygen. For example, it is preferred to carry out the polymerization under a nitrogen atmosphere or to isolate the oxygen by a release film (separator). Further, the obtained (meth)acrylic polymer may be any of a random copolymer, a block copolymer, and a graft copolymer.

The active energy ray to be irradiated during the active energy ray polymerization (photopolymerization) may, for example, be an radiant such as an α ray, a β ray, a γ ray, a neutron ray or an electron ray, or an ultraviolet ray. Among them, ultraviolet ray is particularly preferable. Further, the irradiation energy of the active energy ray, the irradiation time, the irradiation method, and the like are not particularly limited as long as the photopolymerization initiator can be activated to cause the monomer component to react.

Various general solvents can be used in the polymerization of the aforementioned solution. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; and cyclohexane and methylcyclohexane. An alicyclic hydrocarbon; an organic solvent such as a ketone such as methyl ethyl ketone or methyl isobutyl ketone. Further, the above solvents may be used singly or in combination of two or more kinds.

Further, in the polymerization, a polymerization initiator such as a photopolymerization initiator (photoinitiator) or a thermal polymerization initiator may be used depending on the type of the polymerization reaction. Further, the above polymerization initiators may be used singly or in combination of two or more.

The photopolymerization initiator is not particularly limited, and examples thereof include a benzoin ether photopolymerization initiator, an acetophenone photopolymerization initiator, an α-keto alcohol photopolymerization initiator, and an aromatic sulfonamide. Chlorine photopolymerization initiator, photoactive oxime photopolymerization initiator, benzoin photopolymerization initiator, benzyl photopolymerization initiator, diphenyl ketone photopolymerization initiator, shrinkage Ketone photopolymerization initiator, 9-oxosulfur A photopolymerization initiator.

The benzoin ether photopolymerization initiator may, for example, be benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-di Methoxy-1,2-diphenylethan-1-one, anisole methyl ether, and the like. The acetophenone-based photopolymerization initiator may, for example, be 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone or 1-hydroxycyclohexyl phenyl ketone. , 4-phenoxydichloroacetophenone, 4-(tributyl)dichloroacetophenone, and the like. The α-keto alcohol-based photopolymerization initiator may, for example, be 2-methyl-2-hydroxypropiophenone or 1-[4-(2-hydroxyethyl)benzene]-2-methylpropan-1-one. . The aromatic sulfonium chloride-based photopolymerization initiator may, for example, be 2-naphthalenesulfonium chloride or the like. The photoactive oxime-based photopolymerization initiator may, for example, be 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-ruthenium or the like. The benzoin-based photopolymerization initiator may, for example, be benzoin or the like. The benzyl group photopolymerization initiator may, for example, be a benzyl group or the like. The diphenyl ketone photopolymerization initiator may, for example, be diphenyl ketone, benzamidine benzoic acid, 3,3'-dimethyl-4-methoxydiphenyl ketone or polyvinyl diphenyl group. Ketone, α-hydroxycyclohexyl phenyl ketone, and the like. The ketal-based photopolymerization initiator may, for example, be benzyldimethylketal or the like. The aforementioned 9-oxygen sulfur The photopolymerization initiator may, for example, be 9-oxosulfur 2-chloro 9-oxosulfur 2-methyl 9-oxosulfur 2,4-dimethyl 9-oxosulfur Isopropyl 9-oxosulfur 2,4-diisopropyl 9-oxosulfur Dodecyl 9-oxosulfur Wait.

The amount of the photopolymerization initiator to be used is not particularly limited, but is preferably 0.01 to 1 part by weight, more preferably 0.05 to 0.5 part by weight, per 100 parts by weight of the total of the monomer components.

The polymerization initiator used in the solution polymerization may, for example, be an azo polymerization initiator or a peroxide polymerization initiator (for example, benzamidine peroxide or tertiary butyl maleate). , a redox polymerization initiator, and the like. Further, an azo polymerization initiator disclosed in JP-A-2002-69411 is preferred. The above azo polymerization initiator may, for example, be 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis (2-methylpropionic acid) dimethyl ester, 4,4'-azobis-4-cyanovaleric acid, and the like.

The amount of the azo-based polymerization initiator to be used is not particularly limited, but is preferably 0.05 to 0.5 parts by weight, more preferably 0.1 to 0.3 parts by weight, per 100 parts by weight of the total of the monomer components.

Further, a polyfunctional monomer (polyfunctional acrylate) used as the comonomer may also be used in a solvent-type or active energy ray-curable adhesive composition, but for example, in the above-mentioned polyfunctional monomer (polyfunctional acrylic acid) When the ester is mixed with the above-mentioned photopolymerization initiator in a solvent-based adhesive composition, it is subjected to active energy ray hardening after thermal drying.

In the present invention, the (meth)acrylic polymer used in the solvent-based adhesive composition generally has a weight average molecular weight (Mw) of 600,000 to 2.5 million. When considering durability, especially considering heat resistance and flexibility, it is preferably 1,000,000 to 2.5 million, preferably 1.2 million to 2,000,000, and more preferably 1.4 to 1.8 million. When the weight average molecular weight is less than 600,000, when the polymer chains are crosslinked to ensure durability, when the weight average molecular weight is 600,000 or more, the crosslinking point is increased to cause the adhesive (layer). Since the flexibility is lost, the strain on the outer side of the bend (the convex side) and the inner side of the bend (the concave side) which are generated between the respective layers (each film) at the time of the deflection cannot be alleviated, and the layers are easily broken. Further, if the weight average molecular weight is more than 2.5 million, it is difficult to adjust the viscosity to be applied, and a large amount of a diluent solvent is required to increase the cost, and the obtained (meth)acrylic polymer is obtained. The entanglement of the polymer chains with each other becomes complicated, and thus the flexibility is deteriorated, so that each layer (film) is easily broken at the time of deflection. Further, from the viewpoint of workability or coating property, as long as the weight average molecular weight is in the range of 600,000 to less than 1,000,000, a low-viscosity adhesive composition can be obtained, which is preferable. Further, the weight average molecular weight (Mw) means a value measured by GPC (Gel Permeation Chromatography) and calculated in terms of polystyrene.

<(Meth)Acrylic oligomer> The (meth)acrylic oligomer may be contained in the above-mentioned adhesive composition. When the (meth)acrylic oligomer is used, the weight average molecular weight (Mw) is preferably smaller than that of the (meth)acrylic polymer, and the (meth)acrylic oligomer can be used. The (meth)acrylic oligomer is interposed between the (meth)acrylic polymers to reduce the entanglement of the (meth)acrylic polymer, thereby making it easy to deform slightly, and to flex Sexually, it is a better aspect.

The monomer constituting the (meth)acrylic oligomer may, for example, be methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate or isopropyl (meth)acrylate. , (butyl) (meth)acrylate, isobutyl (meth)acrylate, secondary butyl (meth)acrylate, tertiary butyl (meth)acrylate, amyl (meth)acrylate, (methyl) Isoamyl acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, Ethyl (meth) acrylate, isodecyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, eleven (meth) acrylate, (meth) acrylate (meth)acrylic acid and esters such as cyclohexyl (meth) acrylate, isodecyl (meth) acrylate, dicyclopentyl (meth) acrylate, etc. An ester of a cycloalkanol; an aryl (meth)acrylate such as phenyl (meth) acrylate or benzyl (meth) acrylate; a (meth) acrylate obtained from an oxime compound derivative alcohol . These (meth) acrylates may be used singly or in combination of two or more.

The above (meth)acrylic oligomer preferably contains an acrylic monomer having a relatively bulky structure represented by the following as a monomer unit: isobutyl (meth)acrylate or tertiary butyl (meth)acrylate Such alkyl groups have a branched (meth)acrylic acid alkyl ester; (meth)acrylic acid cyclohexyl ester, isodecyl (meth)acrylate (dimethylammonium methacrylate) such as (meth) acrylate having a cyclic structure such as an ester of acrylic acid and an alicyclic alcohol; an aryl (meth) acrylate such as phenyl (meth) acrylate or benzyl (meth) acrylate. By having such a bulky structure of the (meth)acrylic oligomer, the adhesion of the adhesive layer can be further improved. Especially in the case of a large structure, the effect of having a ring structure is high, and the effect of containing a multi-ring is higher. Further, in the case of synthesizing a (meth)acrylic oligomer or when an adhesive layer is formed, it is difficult to inhibit polymerization by using ultraviolet rays. In this case, it is preferred to have a saturated bond, and it is suitable to have a branched structure of an alkyl group. The alkyl (meth)acrylate or the ester with an alicyclic alcohol is used as a monomer constituting the (meth)acrylic oligomer.

From the above viewpoint, a suitable (meth)acrylic oligomer may, for example, be a copolymer of butyl acrylate (BA) with methyl acrylate (MA) and acrylic acid (AA), or cyclohexyl methacrylate ( Copolymer of CHMA) with isobutyl methacrylate (IBMA), copolymer of cyclohexyl methacrylate (CHMA) and isodecyl methacrylate (IBXMA), cyclohexyl methacrylate (CHMA) and propylene Copolymer of 醯福福林 (ACMO), copolymer of cyclohexyl methacrylate (CHMA) and diethyl acrylamide (DEAA), 1-adamantyl acrylate (ADA) and methyl methacrylate Copolymer of (MMA), copolymer of dicyclopentanyl methacrylate (DCPMA) and isodecyl methacrylate (IBXMA), dicyclopentanyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA) ), isodecyl methacrylate (IBXMA), isodecyl acrylate (IBXA), copolymer of cyclopentyl methacrylate (DCPMA) and methyl methacrylate (MMA), dicyclopentanyl acrylate (DCPA) , homopolymers of 1-adamantyl methacrylate (ADMA), 1-adamantyl acrylate (ADA), and the like.

The polymerization method of the (meth)acrylic oligomer is the same as the (meth)acrylic polymer described above, and may be carried out by solution polymerization, emulsion polymerization, bulk polymerization, emulsion polymerization, or irradiation with active energy rays. Polymerization (thermal polymerization, active energy ray polymerization) and the like. Among them, from the viewpoints of transparency, water resistance, cost, and the like, solution polymerization and active energy ray polymerization are preferred. Further, the obtained (meth)acrylic oligomer may be any of a random copolymer, a block copolymer, and a graft copolymer.

The (meth)acrylic oligomer can be used for the solvent-based adhesive composition and the active energy ray-curable adhesive composition in the same manner as the (meth)acryl-based polymer. For example, as the active energy ray-curable adhesive composition, the mixture (monomer mixture) constituting the monomer component of the (meth)acrylic polymer or a partial polymer thereof may be further mixed in the above (A) Acrylic oligomers are used. When the (meth)acrylic oligomer is dissolved in a solvent, the solvent in the adhesive composition can be thermally dried, and then the active energy ray hardening is completed to obtain an adhesive layer.

The weight average molecular weight (Mw) of the (meth)acrylic oligomer used in the solvent-type adhesive composition is preferably 1,000 or more, more preferably 2,000 or more, more preferably 3,000 or more, and still more preferably 4,000 or more. Further, the weight average molecular weight (Mw) of the (meth)acrylic oligomer is preferably 30,000 or less, more preferably 15,000 or less, still more preferably 10,000 or less, and particularly preferably 7,000 or less. By adjusting the weight average molecular weight (Mw) of the (meth)acrylic oligomer to the above range, for example, when the (meth)acrylic polymer is used in combination, the (meth)acrylic oligomer can be used. The polymer is present between the (meth)acrylic polymers to reduce the entanglement of the (meth)acrylic polymer, so that the adhesive layer is easily deformed by a small strain, and the strain applied to other layers can be reduced. Therefore, it is preferable to suppress cracking of each layer and peeling of the adhesive layer and other layers. Further, the weight average molecular weight (Mw) of the (meth)acrylic oligomer is the same as the above (meth)acrylic polymer, and is measured by GPC (Gel Permeation Chromatography) and The value calculated by polystyrene conversion.

When the (meth)acrylic oligomer is used as the above-mentioned adhesive composition, the blending amount thereof is not particularly limited, and it is preferably 70 parts by weight or less based on 100 parts by weight of the (meth)acrylic polymer. Preferably, it is 1 to 70 parts by weight, more preferably 2 to 50 parts by weight, and still more preferably 3 to 40 parts by weight. When the blending amount of the (meth)acrylic oligomer is adjusted to the above range, a (meth)acrylic oligomer can be appropriately present between the (meth)acrylic polymers ( The entanglement of the methyl methacrylate polymer is reduced, so that the adhesive layer is easily deformed by a small strain, and the strain applied to other layers can be reduced, thereby suppressing cracking of each layer and peeling between the adhesive layer and other layers. And so on, but for the better.

<Crosslinking Agent> The adhesive composition of the present invention may contain a crosslinking agent. As the crosslinking agent, an organic crosslinking agent or a polyfunctional metal chelate compound can be used in any of the solvent-based or active energy ray-curable adhesive compositions. Examples of the organic crosslinking agent include an isocyanate crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, and an imide crosslinking agent. Polyfunctional metal chelates are those in which a polyvalent metal is covalently bonded or coordinately bonded to an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. The atom which may be covalently bonded or coordinately bonded to the organic compound may, for example, be an oxygen atom, and the organic compound may, for example, be an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound or a ketone compound. In particular, when it is a solvent-based adhesive composition, it is preferably a peroxide-based crosslinking agent or an isocyanate crosslinking agent, and a peroxide-based crosslinking agent is preferably used. The peroxide-based crosslinking agent is exemplified by removing the hydrogen of the side chain of the (meth)acryl-based polymer to generate a radical, and causing the side chains of the (meth)acrylic polymer to proceed with each other. Cross-linking, therefore, when cross-linking is carried out using an isocyanate-based crosslinking agent (for example, a polyfunctional isocyanate-based crosslinking agent), the crosslinking state is relatively gentle, and it is easy to maintain a small strain deformation. At the same time, the cohesive force is improved, and it is preferable in terms of flexibility in suppressing cracking or peeling under normal temperature and high temperature environment. Further, an isocyanate crosslinking agent (particularly a trifunctional isocyanate crosslinking agent) is preferred from the viewpoint of durability, and a peroxide crosslinking agent and an isocyanate crosslinking agent (especially a difunctional one) The isocyanate crosslinking agent is preferred from the viewpoint of flexibility. Both the peroxide crosslinker and the difunctional isocyanate crosslinker form a soft two-dimensional crosslink. In contrast, the trifunctional isocyanate crosslinker forms a relatively strong three-dimensional crosslink. In the case of deflection, a softer cross-linking, that is, two-dimensional cross-linking is advantageous. However, only two-dimensional cross-linking will result in poor durability and easy peeling. Therefore, the cross-linking of two-dimensional cross-linking and three-dimensional cross-linking is relatively good, so that a trifunctional isocyanate cross-linking agent and peroxidation are used together. A cross-linking agent or a difunctional isocyanate-based cross-linking agent is preferred. Further, the active energy ray-curable adhesive composition is preferably obtained by polymerization using the above-mentioned polyfunctional monomer from the viewpoint of productivity and thick film coating, but it is also possible to use the above crosslinking agent or Used in combination with the aforementioned polyfunctional monomer. For example, a crosslinking agent may be mixed in a mixture (monomer mixture) constituting the monomer component of the (meth)acrylic polymer or a partial polymer thereof, and before and after the active energy ray of the adhesive composition is hardened, Thermal drying is performed to complete the reaction of the crosslinking agent.

The amount of the crosslinking agent used is, for example, 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, more preferably 0.3 to 3 parts by weight, per 100 parts by weight of the (meth)acrylic polymer. When it is within the above range, the flexural resistance is excellent and it is preferable.

Further, when the peroxide-based crosslinking agent is used alone, it is preferably 0.5 to 5 parts by weight, more preferably 1 to 3 parts by weight, per 100 parts by weight of the (meth)acryl-based polymer. If it is within the above range, it is possible to sufficiently improve the cohesive force while maintaining the degree of easy strain deformation, and it is possible to improve the durability and the flex resistance.

Further, when a peroxide-based crosslinking agent and an isocyanate-based crosslinking agent are used in combination, the weight ratio of the peroxide-based crosslinking agent to the isocyanate-based crosslinking agent (peroxide crosslinking agent/isocyanate crosslinking agent) The lower limit value is preferably 1.2 or more, more preferably 1.5 or more, and still more preferably 3 or more. Further, the upper limit of the weight ratio is preferably 500 or less, more preferably 300 or less, and still more preferably 200 or less. If it is within the above range, it is preferable to sufficiently increase the cohesive force while maintaining the ease of strain deformation.

<Other Additives> Further, the adhesive composition of the present invention may contain other known additives, and a polyether compound such as various decane coupling agents or polypropylene glycol diols, such as various decane coupling agents and polypropylene glycol, may be appropriately added depending on the intended use. Powder, dye, surfactant, plasticizer, tackifier, surface lubricant, leveling agent, softener, antioxidant, anti-aging agent, light stabilizer, ultraviolet absorber, polymerization inhibitor An antistatic agent (an alkali metal salt or an ionic liquid of an ionic compound, an ionic solid, etc.), an inorganic or organic filler, a metal powder, a granule, a foil, or the like. Further, a redox system to which a reducing agent is added may be employed within a controllable range. Further, from the viewpoint of ensuring workability or peeling workability of the separator, it is preferred to use an antioxidant, and in particular, when a peroxide-based crosslinking agent is used as a crosslinking agent, it is preferred to polymerize with respect to the above (meth)acrylic acid. 0.05 to 3 parts by weight of an antioxidant (particularly a phenolic antioxidant) is used in 100 parts by weight.

The method for preparing the above-mentioned adhesive composition is not particularly limited, and a known method can be employed. For example, as described above, the solvent-based acrylic adhesive composition is added by a (meth)acrylic polymer, if necessary. The component (for example, the above-mentioned (meth)acrylic oligomer, a crosslinking agent, a decane coupling agent, a solvent, an additive, etc.) is mixed and produced. Further, as described above, the active energy ray-curable acrylic pressure-sensitive adhesive composition is a component obtained by adding a monomer mixture or a part thereof to a polymer (for example, the aforementioned photopolymerization initiator, polyfunctional monomer, the aforementioned It is produced by mixing (meth)acrylic oligomer, a crosslinking agent, a decane coupling agent, a solvent, an additive, etc.).

The aforementioned adhesive composition preferably has a viscosity suitable for handling and coating. Therefore, the active energy ray-curable acrylic adhesive composition preferably contains a partial polymer of the monomer mixture. The polymerization rate of the above partial polymer is not particularly limited, but is preferably 5 to 20% by weight, more preferably 5 to 15% by weight.

Further, the polymerization rate of the above partial polymer can be determined in the following manner. A part of the polymer was sampled as a sample. The sample was weighed to obtain its weight, and it was designated as "the weight of a part of the polymer before drying". Next, the sample was dried at 130 ° C for 2 hours, and the dried sample was weighed to obtain the weight, and it was designated as "the weight of the partially polymer after drying". Then, the weight of the sample which was dried at 130 ° C for 2 hours was determined from "the weight of the partially polymer before drying" and the "weight of the partially polymer after drying", and the weight was determined as "weight reduction". (volatile part, unreacted monomer weight). The polymerization rate (% by weight) of the partial polymer of the monomer component was determined from the obtained "weight of the partially polymer before drying" and "weight reduction amount" by the following formula. The polymerization rate (% by weight) of a part of the polymer of the monomer component = [1 - (weight reduction amount) / (weight of part of polymer before drying)] × 100

[Other Adhesive Layer] Among the adhesive layers used in the laminate for a flexible image display device of the present invention, the second adhesive layer may be disposed on the retardation film to be in contact with the polarizing film. The opposite side of the face (see Figure 2).

In the adhesive layer used for the laminated body for a flexible image display device of the present invention, the third adhesive layer may be opposite to the second adhesive layer of the transparent conductive layer constituting the touch sensor. The third adhesive layer is disposed on the opposite side of the contact surface (see Fig. 2).

In the adhesive layer used for the laminated body for a flexible image display device of the present invention, the third adhesive layer may be disposed on the transparent conductive layer and the first adhesive on the transparent conductive layer constituting the touch sensor. The opposite side of the face where the layers meet (see Figure 3).

Further, when the second adhesive layer is used as the first adhesive layer, and other adhesive layers (for example, the third adhesive layer or the like) are further used, the adhesive layers may have the same composition (the same adhesive composition). ), the same characteristics, may also have different characteristics, there is no particular limitation, but from the point of view of workability, economy, flexibility, all adhesive layers should be substantially the same composition, the same characteristics Adhesive layer.

<Formation of Adhesive Layer> The method of forming the pressure-sensitive adhesive layer may be, for example, applying the solvent-based adhesive composition to a release-treated separator (release film) or the like, and drying and removing a polymerization solvent or the like. a method of applying an adhesive layer to a polarizing film, coating a solvent-based adhesive composition, and drying a polymerization solvent to form an adhesive layer on a polarizing film or the like; and coating an active energy ray-curable adhesive composition A method of forming a separator or the like which has been subjected to peeling treatment, and irradiating an active energy ray to form it. Further, heat drying may be performed in addition to the active energy ray irradiation as needed. Further, when the adhesive composition is applied, one or more solvents other than the polymerization solvent may be appropriately added. A specific method of preparing the adhesive layer using the above-described active energy ray-curable adhesive composition is, for example, a preferred embodiment: after modulating a monomer mixture (monomer slurry), irradiating the active energy ray to a desired viscosity After a part of the polymerization polymerization is carried out to prepare a partially polymerized monomer slurry, an additive such as a polyfunctional monomer or a decane coupling agent is mixed, and the polymerization rate (reaction rate) is 90% or more as a scale, and then the active energy ray is irradiated to carry out polymerization. This modulates the adhesive layer. Further, a method of preparing a partially polymerized monomer slurry obtained by partially polymerizing a monomer mixture (monomer slurry) containing a monomer containing a guanamine group in advance, and mixing other additives or the like to carry out polymerization, thereby preparing an adhesive a method of layer (method A); or a partially polymerized monomer slurry obtained by partially polymerizing the above-mentioned monomer mixture (monomer slurry) additionally contains a mercapto group-containing monomer, and is mixed with other additives to carry out polymerization. This method of modulating the adhesive layer (Method B). For these methods, since the monomer containing a guanamine group is used, it is more severe even in a high temperature environment (for example, 85 ° C) or a high temperature, high humidity environment (for example, 60 ° C × 95% RH). After the conditions, there will be no cracking or peeling in the face of repeated deflection, and it has excellent adhesion. Further, the detailed reason for the adhesion is not known, but it is presumed that in the method A, a high molecular weight sol component having a weight average molecular weight of about 1,000,000 to 3,000,000 can be produced, and a monomer containing a guanamine group is contained. The adhesion of the surface of the adhesive will be good. On the other hand, although the method B has no problem of adhesion to the adherend, it is presumed that a high molecular weight sol component having a weight average molecular weight of about 1,000,000 to 3,000,000 can be produced without (or difficult to contain) an amidino group. Monomer, in this case, in terms of the adhesion to the surface of the adherend, we speculate that the method A is preferred. Further, since the sol component is easily segregated to the surface of the adherend, it is presumed that the low molecular weight sol component having a weight average molecular weight of less than 1,000,000 lowers the strength of the material at the interface between the adhesive layer and the adherend (not only the adhesive layer and the adherend) At the interface, there is also a case where cohesive failure occurs in the adhesive layer, resulting in a decrease in adhesion.

The release treated release member is preferably a polyoxynitride release liner. When the adhesive composition of the present invention is applied to the lining material and dried to form an adhesive layer, the method of drying the adhesive may be carried out by a suitable and appropriate method for the purpose. It is desirable to use a method of heating and drying the above coating film. The heating and drying temperature is preferably 40 to 200 ° C, more preferably 50 to 180 ° C, and particularly preferably 70 to 170 ° C, in order to prepare an acrylic adhesive using a (meth)acrylic polymer. By setting the heat drying temperature within the above range, an adhesive having excellent adhesive properties can be obtained.

The drying time can be appropriately adjusted for the appropriate time. The drying time is, for example, preferably 5 seconds to 20 minutes, and more preferably 5 seconds to 10 minutes, and 10 seconds to 5 minutes, in order to prepare an acrylic adhesive using a (meth)acrylic polymer. good.

The coating method of the above-mentioned adhesive composition can employ various methods. Specific examples thereof include roll coating, contact roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roller coating, bar coating, blade coating, and air knife coating. Curtain coating, lip coating, a method such as a die coating method using a die coater or the like.

The thickness of the adhesive layer used in the laminate for a flexible image display device of the present invention is preferably from 1 to 200 μm, more preferably from 5 to 150 μm, still more preferably from 10 to 100 μm. The adhesive layer may be a single layer or a laminated structure. If it is in the above range, the deflection is not inhibited, and the viewpoint of adhesion (resistance to retention) is also preferable. Further, in the case of having a plurality of adhesive layers, the entire adhesive layer is preferably within the above range.

The present invention is characterized in that the adhesive layer of the adhesive layer for a flexible image display device of the present invention has a stress of 100% modulus of 0.01 to 0.1 N/mm ² and a stress of 500% modulus of the adhesive layer. It is 0.05~0.2N/mm ² . When the stress of the 100% modulus and the stress of the 500% modulus simultaneously satisfy the above range, the laminated body for a flexible image display device is applied to other layers constituting the laminate for the flexible image display device during flexing. The strain of each layer becomes small, so that the cracking of the respective layers and the peeling of the adhesive layer can be suppressed, which is preferable. In order to adjust the stress of 100% modulus and the stress of 500% modulus to the above range, the adhesive composition used for the formation of the adhesive layer may be exemplified by the following method. When a solvent-based adhesive composition is used, the first method of the solvent type is a (meth)acrylic polymer obtained by copolymerizing a (meth)acrylic monomer having a long-chain alkyl group. In the first method of the solvent type herein, it is preferred to contain 40% by weight or more and 99% by weight of the (meth)acrylic monomer having a long-chain alkyl group with respect to the total monomer. In the solvent-based second method, the peroxide-based crosslinking agent is used alone as a crosslinking agent, and is added in an amount of 0.5 part by weight or more and 5 parts by weight or less based on 100 parts by weight of the (meth)acryl-based polymer. . In the third method of the solvent type, the peroxide-based crosslinking agent and the isocyanate-based crosslinking agent are used as a crosslinking agent, and the weight ratio of the peroxide-based crosslinking agent to the isocyanate-based crosslinking agent is used (peroxidation). The amount of the crosslinking agent/isocyanate crosslinking agent is 1.2 or more and 500 or less, and the amount of the peroxide crosslinking agent is 0.2 weight by weight based on 100 parts by weight of the (meth)acrylic polymer. More than one. The fourth method of the solvent type is the second method or the third method of the solvent type, and the (meth)acrylic oligomer 1 is further added as described above with respect to 100 parts by weight of the (meth)acrylic polymer. It is more than 100 parts by weight or more. On the other hand, when the active energy ray-curable adhesive composition is used, the first method of the active energy ray-curing type is a (meth)acrylic monomer having a long-chain alkyl group as a main component and contains A mixture of a monomer having a carbon number of 1 or more and 5 or less or a monomer of a functional group (monomer mixture) or a part of the polymer of the mixture is polymerized together with the polyfunctional monomer. In the first method of the active energy ray-curing type, the first method of the active energy ray-curing type is used as the (meth)acrylic monomer having a long-chain alkyl group, and has a carbon number of 10 or more and 30. A mixture (monomer mixture) of a (meth)acrylic monomer having an alkyl group and a (meth)acrylic monomer having an alkyl group having 6 or more and 9 or less, or a partial polymer of the mixture. In the first method and the second method of the active energy ray-curing type, it is preferable that the content of the (meth)acrylic monomer having a long-chain alkyl group is 60% by weight or more based on the total monomer. More preferably, it is 70% by weight or more, and on the other hand, it is preferably 100% by weight or less, and more preferably 99% by weight or less. Further, when a mixture of a (meth)acrylic monomer having an alkyl group having 10 or more carbon atoms and 30 or less and a (meth)acrylic monomer having an alkyl group having 6 or more and 9 or less carbon atoms is used, the mixing ratio is used. It is preferably ((meth)acrylic monomer having an alkyl group having 10 or more carbon atoms and 30 or less): ((meth)acrylic monomer having an alkyl group having 6 or more and 9 or less carbon atoms) = 40 : 60~90:10. By using the first method of the solvent type, the fourth method, and the first method of the active energy ray-curing type, the second method, the stress of 100% modulus is controlled to 0.01 to 0.1 N/mm ² , and the following adhesion can be obtained. Agent layer: The adhesive layer is easy to deform against minute strain, and can reduce the strain applied to other layers (layers), especially preventing cracking of various layers and peeling of the adhesive layer at normal temperature. In addition, if the upper limit of the stress of the 100% modulus is more than 0.1 N/mm ² , especially in a normal temperature (room temperature) environment, the adhesive layer is less likely to be deformed by minute strain, thereby causing a decrease in flexibility (cracking or peeling). When the lower limit of the stress of the 100% modulus is less than 0.01 N/mm ² , the adhesive layer may be easily deformed, whereby the adhesion is lowered and the peeling is liable to occur, which is unfavorable. Further, by using the first method to the fourth method of the solvent type and the first method to the second method of the active energy ray-curing type, the stress of 500% modulus is controlled to a range of 0.05 to 0.2 N/mm ² . Ensure the cohesive force of the adhesive layer, especially when continuously flexing in a high temperature environment, prevent cohesive failure of the adhesive layer, and prevent cracking and adhesion of the layers when flexed at room temperature (room temperature) or high temperature environment. Peeling of the agent layer occurs. In addition, if the lower limit of the stress of the 500% modulus is less than 0.05 N/mm ² , the cohesive force of the adhesive layer may be insufficient, especially in a high temperature environment, peeling due to cohesive failure of the adhesive layer may occur, and if 500% mode When the upper limit of the number of stresses is more than 0.2 N/mm ² , the cohesive force becomes too high, and it is unfavorable because the adhesion is lowered and the peeling is liable to occur.

The flexible image display device of the present invention the laminate of 100% modulus stress of the adhesive agent layer is suitably used ^{0.01 ~ 0.08N / mm 2, 0.01} ~ 0.06N / mm 2 Preferably, 0.01 ~ 0.05N / mm ² More preferably, 0.01 to 0.04 N/mm ^{2 is} particularly preferred. By adjusting to the above range, the adhesive layer can be easily deformed by a small strain, and the strain applied to other layers (layers) can be reduced, in particular, the cracking of the layers and the peeling of the adhesive layer at normal temperature can be prevented. Occurs, but is the best.

The stress of the 500% modulus of the adhesive layer used in the laminate for the flexible image display device of the present invention is preferably 0.085 to 0.2 N/mm ² , preferably 0.1 to 0.2 N/mm ² , and 0.12 to 0.2 N/mm ^{2 .} More preferably, 0.15~0.2N/mm ^{2 is} especially good. By adjusting to the above range, the cohesive force of the adhesive layer can be ensured, and when it is bent at a normal temperature (room temperature) environment or particularly in a high temperature environment, cracking of each layer and cohesive failure of the adhesive layer can be prevented. Exfoliation occurs, which is a preferred aspect.

The stress of the 700% modulus of the adhesive layer used in the laminate for the flexible image display device of the present invention is preferably 0.05 to 0.3 N/mm ² , preferably 0.1 to 0.3 N/mm ² , and 0.13 to 0.3 N/mm ^{2 .} More preferably, 0.18~0.3N/mm ^{2 is} especially good, and 0.23~0.3N/mm ^{2 is the} best. By adjusting to the above range, the cohesive force of the adhesive layer can be ensured, and when it is bent at a normal temperature (room temperature) environment or particularly in a high temperature environment, cracking of each layer and cohesive failure of the adhesive layer can be prevented. Exfoliation occurs, which is a preferred aspect.

Further, in order to make the adhesive layer for the flexible image display device of the present invention, the stress of 100% modulus of the adhesive layer is 0.01 to 0.08 N/mm ² and the stress of 500% modulus is 0.085 to 0.2 N/mm. ² . The solvent-based adhesive composition is solution-polymerized using a (meth)acrylic monomer having an alkyl group having 4 to 12 carbon atoms, and is prepared by using an isocyanate crosslinking agent and a peroxide crosslinking agent in combination. The weight ratio of the peroxide-based crosslinking agent to the isocyanate crosslinking agent (peroxide crosslinking agent/isocyanate crosslinking agent) is 1.5 to 200, and the adhesive composition is crosslinked. It is preferable to obtain an adhesive layer having a stress of the aforementioned modulus. Further, when a (meth)acrylic oligomer is used in the preparation of the pressure-sensitive adhesive layer, the solvent-based adhesive composition can be easily obtained by using an isocyanate-based crosslinking agent and a peroxide-based crosslinking agent. A number of stress adhesive layers are preferred. Specifically, the (meth)acrylic oligomer having a weight average molecular weight (Mw) of 3,000 or more and 10,000 or less and a weight ratio of the peroxide-based crosslinking agent to the isocyanate-based crosslinking agent can be used. It is 40 or more and 150 or less. Further, in the case of the active energy ray-curable adhesive composition, a (meth)acrylic monomer having an alkyl group having 6 to 30 carbon atoms is used, and a monomer component other than the polyfunctional monomer is used. The mixture (monomer mixture) or a part thereof polymer 100% by weight contains 0.05 to 3% by weight of a polyfunctional acrylate to carry out polymerization, and an adhesive layer capable of exerting a crosslinking effect and having a stress of the aforementioned modulus can be obtained. For the better.

The modulus (X) of the 100% modulus of the adhesive layer used in the laminate for the flexible image display device of the present invention and the modulus (Y) of the stress (Y) of the 500% modulus of the adhesive layer (Y/X) It should be 1.2~20, 2~10 is better, 2.4~8 is better, and 2.7~6 is better. When the modulus ratio (Y/X) is within the above range, the cohesive force can be improved while maintaining the ease of strain deformation, which is preferable. That is, in the relationship between the stress (X) of the 100% modulus and the stress (Y) of the 500% modulus, the stress (Y) of the 500% modulus is preferably a fixed ratio with respect to the stress (X) of the 100% modulus. In particular, the stress (X) of the 100% modulus is small and the stress (Y) of the 500% modulus is large, which is preferable in terms of both the normal temperature environment and the flexibility in a high temperature environment. In particular, the stress (Y) of the 500% modulus affects the peeling during continuous flexing in a high temperature environment, so it should be set to 0.1 to 0.2 N/mm ² . However, when the modulus ratio (Y/X) is more than 20, it is difficult to achieve both the ease of deformation and the cohesive force.

In the laminate for a flexible image display device of the present invention, the gel fraction of the adhesive layer is preferably 55 to 90% by weight, preferably 57 to 90% by weight, more preferably 60 to 88% by weight, and 62 to 88%. The weight % is better, 65 to 86% by weight is particularly preferred, and 70 to 86% by weight is optimal. When the gel fraction of the pressure-sensitive adhesive layer is within the above range, the appearance (adhesive dent, etc.), workability, durability, and flexibility are good, and in particular, it is easy to achieve both flexibility in a normal temperature environment and a high temperature environment. Sex, but the best.

The upper limit of the glass transition temperature (Tg) of the adhesive layer used for the laminate for a flexible image display device of the present invention is preferably 5 ° C or less. If the flexibility in a low temperature environment or a high speed region is considered, it is more preferably -20 ° C or less, and more preferably -25 ° C or less. As long as the Tg of the adhesive layer is within the above range, the adhesive layer is hard to be hardened even when it is deflected in a low temperature environment or in a high speed region where the bending speed exceeds 1 second/time, and the stress relaxation property is excellent. In this way, a laminate for a flexible or foldable flexible image display device and a flexible image display device in which the laminate for the flexible image display device is disposed can be realized.

In the adhesive layer for a flexible image display device of the present invention, the total light transmittance (according to JIS K7136) in the visible light wavelength region is preferably 85% or more, and more preferably 90% or more.

[Transparent Conductive Layer] The member having the transparent conductive layer is not particularly limited, and a known one can be used, but it may be a member having a transparent conductive layer on a transparent substrate such as a transparent film or a member having a transparent conductive layer and a liquid crystal cell. .

The transparent substrate may be a transparent material, and examples thereof include a substrate (for example, a sheet-like or film-like substrate or a plate-like substrate) made of a resin film or the like. The thickness of the transparent substrate is not particularly limited, but is preferably about 10 to 200 μm, and more preferably about 15 to 150 μm.

The material of the resin film is not particularly limited, and various plastic materials having transparency can be cited. The material may, for example, be a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, an acetate resin, a polyether oxime resin, a polycarbonate resin, or a polyamide resin. Polyimide resin, polyolefin resin, (meth)acrylic resin, polyvinyl chloride resin, polydivinylidene resin, polystyrene resin, polyvinyl alcohol resin, polyarylate Resin, polyphenylene sulfide resin, etc. Among these, a polyester resin, a polyimide resin, and a polyether oxime resin are particularly preferable.

Further, an etching treatment or a primer treatment may be performed on the surface of the transparent substrate in advance by sputtering, corona discharge, flame, ultraviolet ray irradiation, electron beam irradiation, chemical conversion, oxidation, or the like to enhance the transparent conductive layer provided thereon. Adhesion to the aforementioned transparent substrate. Further, before the transparent conductive layer is provided, it may be dedusted and purified by solvent washing or ultrasonic cleaning as needed.

The constituent material of the transparent conductive layer is not particularly limited, and may be selected from the group consisting of indium, tin, zinc, gallium, germanium, titanium, lanthanum, zirconium, magnesium, aluminum, gold, silver, copper, palladium, tungsten, and molybdenum. At least one metal or metal oxide in the group or an organic conductive polymer such as polythiophene is formed. The metal oxide may further contain a metal atom represented by the above group as needed. It is preferable to use, for example, indium oxide (ITO) containing tin oxide, tin oxide containing antimony, etc., and ITO is particularly preferably used. The ITO preferably contains 80 to 99% by weight of indium oxide and 1 to 20% by weight of tin oxide.

Further, the ITO may be crystalline ITO or amorphous (amorphous) ITO. The crystalline ITO can be obtained by applying a high temperature during sputtering or by further heating the amorphous ITO.

The thickness of the transparent conductive layer of the present invention is preferably 0.005 to 10 μm, preferably 0.01 to 3 μm, more preferably 0.01 to 1 μm. If the thickness of the transparent conductive layer is less than 0.005 μm, the change in the resistance value of the transparent conductive layer tends to become large. On the other hand, when it is more than 10 μm, the productivity of the transparent conductive layer is lowered, the cost is also increased, and the optical characteristics tend to be lowered.

The total light transmittance of the transparent conductive layer of the present invention is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more.

The transparent conductive layer of the present invention preferably has a density of 1.0 to 10.5 g/cm ³ and preferably 1.3 to 3.0 g/cm ³ .

The surface resistivity of the transparent conductive layer of the present invention is preferably 0.1 to 1000 Ω/□, and preferably 0.5 to 500 Ω/□, more preferably 1 to 250 Ω/□.

The method for forming the transparent conductive layer is not particularly limited, and a conventionally known method can be employed. Specifically, a vacuum vapor deposition method, a sputtering method, and an ion plating method can be exemplified. Also, an appropriate method can be used in accordance with the required film thickness.

Further, an undercoat layer, an anti-oligomer layer, or the like may be provided between the transparent conductive layer and the transparent substrate as needed.

The transparent conductive layer is required to constitute a touch sensor and is configured to be bendable.

In the laminated body for a flexible image display device of the present invention, the transparent conductive layer constituting the touch sensor and the second adhesive layer may be disposed on a surface of the second adhesive layer that is in contact with the retardation film. Opposite side (see Figure 2).

In the laminated body for a flexible image display device of the present invention, the transparent conductive layer constituting the touch sensor can be disposed on the surface of the first adhesive layer that is in contact with the protective film, and the first adhesive layer is disposed on the surface of the first adhesive layer Side (see Figure 3).

Further, in the laminated body for a flexible image display device of the present invention, the transparent conductive layer constituting the touch sensor can be disposed between the protective film and the window film (OCA) (see FIG. 3).

When the transparent conductive layer is used for a flexible image display device, it can be suitably applied to a liquid crystal display device in which a touch sensor is embedded in a built-in type or an upper type, and in particular, the touch sensor can be embedded in the touch sensor. (Incorporated in) an organic EL display panel.

[Electrically Conductive Layer (Antistatic Layer)] The laminate for a flexible image display device of the present invention may have a conductive layer (conductive layer or antistatic layer). Since the laminated body for a flexible image display device has a flexing function and has a very small structural thickness, it has a large reactivity with respect to weak static electricity generated in a manufacturing step or the like, and is easily damaged, but by the above-mentioned laminated body It is preferable to provide a conductive layer to greatly reduce the load caused by static electricity in a manufacturing process or the like.

Further, one of the flexible image display devices including the above-mentioned laminated body is characterized in that it has a flexing function, but after being continuously deflected, static electricity is generated due to shrinkage between the film (substrate) of the flexure portion. . Therefore, if the laminated body is provided with conductivity, the generated static electricity can be quickly removed, and the damage caused by static electricity to the image display device can be reduced, which is preferable.

Further, the conductive layer may be an undercoat layer having a conductive function, an adhesive containing a conductive component, or a surface-treated layer containing a conductive component. For example, a method may be employed in which a conductive layer is formed between a polarizing film and an adhesive layer by using an antistatic agent composition containing a conductive polymer such as polythiophene and a binder. Further, an adhesive containing an ionic compound which is an antistatic agent or the like can also be used. Further, the conductive layer preferably has one or more layers, and may have two or more layers.

[Flexible image display device] The flexible image display device of the present invention includes the laminate for the flexible image display device and the organic EL display panel, and the organic EL display panel is provided with a laminate for the flexible image display device on the viewing side. Body, and is configured to be bendable. Although it is an arbitrary option, it is possible to arrange a window on the viewing side of the laminated body for a flexible image display device (see FIGS. 2 to 4).

Fig. 2 is a cross-sectional view showing an embodiment of a flexible image display device of the present invention. The flexible image display device 100 includes a laminate 11 for a flexible image display device and an organic EL display panel 10 that is bendable. Further, the organic EL display panel 10 is provided with a laminated body 11 for a flexible image display device on the viewing side, and the flexible image display device 100 is configured to be bendable. Further, although it is an optional option, the transparent window 40 can be disposed on the viewing side of the flexible image display device with the first adhesive layer 12-1 interposed therebetween.

The laminated body 11 for a flexible image display device includes the optical layered body 20 and an adhesive layer constituting the second adhesive layer 12-2 and the third adhesive layer 12-3.

The optical laminate 20 includes a polarizing film 1, a protective film 2 of a transparent resin material, and a retardation film 3. The protective film 2 of a transparent resin material is bonded to the first surface on the viewing side of the polarizing film 1. The retardation film 3 is bonded to the second surface of the polarizing film 1 different from the first surface. The polarizing film 1 and the retardation film 3 are films for generating circularly polarized light or compensating for a viewing angle, for example, in order to prevent light incident on the inside from the viewing side of the polarizing film 1 from being internally reflected and emitted to the viewing side.

In the present embodiment, a protective film is provided on both surfaces of the polarizing film, and a protective film is provided on only one surface, and the polarizing film itself is used as compared with the polarizing film used in the conventional organic EL display device. A polarizing film having a very thin thickness (20 μm or less) is also used, so that the thickness of the optical layered body 20 can be reduced. Further, since the polarizing film 1 is extremely thin compared with the polarizing film used in the conventional organic EL display device, the stress caused by the expansion and contraction due to temperature or humidity conditions is extremely small. Therefore, the stress generated by the contraction of the polarizing film greatly reduces the possibility of deformation such as warpage caused by the adjacent organic EL display panel 10, and the display quality due to deformation and the destruction of the panel sealing material can be greatly suppressed. Further, by using a polarizing film having a small thickness, it is preferable that the deflection is not hindered.

When the optical layered body 20 is bent to the inner side of the protective film 2 side, the thickness of the optical layered body 20 (for example, 92 μm or less) is thinned, and 100% modulus and 500% mode are as described above. The number 1 of the first adhesive layer 12-1 is disposed on the opposite side of the protective film 2 from the retardation film 3, and the stress applied to the optical laminate 20 can be reduced, whereby the optical laminate can be formed. The body 20 can be bent, and the cracking of the layers in the flexure and the peeling of the adhesive layer can be suppressed. Finally, the flexible image display device can be made to be bendable by the laminated body 11. Moreover, it is also possible to set an appropriate range of 100% modulus and 500% modulus in accordance with the ambient temperature of the flexible image display device.

Although it is an optional option, the bendable transparent conductive layer 6 constituting the touch sensor can be further disposed on the retardation film 3 on the side opposite to the protective film 2 of the retardation film 3. The transparent conductive layer 6 can be formed by directly bonding the retardation film 3 by a manufacturing method as disclosed in Japanese Laid-Open Patent Publication No. 2014-219667, whereby the thickness of the optical laminate 20 can be reduced, and the thickness can be further reduced. The stress applied to the optical laminate 20 when the optical laminate 20 is bent.

Although it is an optional option, the adhesive layer which comprises the 3rd adhesive layer 12-3 may further arrange|position the transparent conductive layer 6 on the side opposite to the retardation film 3 of this transparent conductive layer 6. In the present embodiment, the second adhesive layer 12-2 is directly bonded to the transparent conductive layer 6. By providing the second adhesive layer 12-2, the stress applied to the optical laminate 20 when the optical laminate 20 is bent can be further reduced.

The flexible image display device shown in FIG. 3 is almost the same as that shown in FIG. 2, but differs in the following points: in the flexible image display device of FIG. 2, the phase difference film 3 is attached to the retardation film 3 The bendable transparent conductive layer 6 constituting the touch sensor is disposed on the opposite side of the protective film 2, whereas the flexible image display device of FIG. 3 is attached to the first adhesive layer 12-1. The bendable transparent conductive layer 6 constituting the touch sensor is disposed on the side opposite to the protective film 2 of the first adhesive layer 12-1. Further, in the flexible image display device of FIG. 2, the third adhesive layer 12-3 is disposed on the opposite side of the transparent conductive layer 2 opposite to the retardation film 3, and the transparent conductive layer 2 is disposed. On the other hand, in the flexible video display device of FIG. 3, the second adhesive layer 12-2 is disposed on the retardation film 3 on the side opposite to the protective film 2 of the retardation film 3.

In addition, the third adhesive layer 12-3 can be disposed when the laminated body 11 for the flexible image display device is disposed on the viewing side of the viewing window 40.

The flexible video display device of the present invention can be suitably used as a flexible liquid crystal display device, an organic EL (electroluminescence) display device, or an image display device such as electronic paper. Moreover, it can be used regardless of the touch panel or the like such as a resistive film method or a capacitive method.

Further, as shown in FIG. 4, the flexible image display device of the present invention can be used as a built-in type flexible image display device in which the transparent conductive layer 6 constituting the touch sensor is embedded in the organic EL display panel 10-1. Example

The embodiments of the invention are described below, but the specific examples are not intended to limit the invention. Further, the numerical values in the tables are blending amounts (addition amounts), and the solid content or solid content ratio (weight basis) is shown. The contents of the blending and the evaluation results are shown in Tables 1 to 6.

[Example 1] [Polarizing film] An amorphous polyethylene terephthalate (hereinafter also referred to as "PET") (IPA copolymerized PET) film having a 7 mol% isodecanoic acid unit (thickness: 100 μm) was prepared. As a thermoplastic resin substrate, the surface was subjected to corona treatment (58 W/m ² /min). On the other hand, it is prepared to add 1% by weight of acetamidine-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: GOHSEFIMER Z200 (average degree of polymerization: 1200, degree of saponification: 98.5 mol%, B) A PVA (degree of polymerization: 4,200% saponification degree: 99.2%), and a coating liquid of PVA-based resin of 5.5% by weight of PVA aqueous solution, so that the film thickness after drying becomes The coating was applied at 12 μm, and dried by hot air drying in a gas atmosphere at 60 ° C for 10 minutes, and then a laminate having a PVA-based resin layer on the substrate was prepared.

The laminate was then first extended 1.8 times in the air at 130 ° C in the free end (air assisted extension) to form an extended laminate. Next, the PVA layer was subjected to an insolubilization step, that is, the extended laminate was immersed in a boric acid insoluble aqueous solution at a liquid temperature of 30 ° C for 30 seconds to orient the PVA molecules contained in the extended laminate. The boric acid insoluble aqueous solution in this step is such that the boric acid content is 3 parts by weight based on 100 parts by weight of water. The extended laminate is dyed to form a colored laminate. The coloring layering system immerses the extended laminated body in a dyeing liquid containing iodine and potassium iodide at a liquid temperature of 30 ° C for at any time so that the single transmittance of the PVA layer constituting the finally formed polarizing film is 40 to 44%. This is obtained by dyeing the PVA layer contained in the extended laminate with iodine. In this step, the dyeing liquid is water in a solvent, and the iodine concentration is in the range of 0.1 to 0.4% by weight, and the potassium iodide concentration is set to be in the range of 0.7 to 2.8% by weight. The concentration ratio of iodine to potassium iodide is 1 to 7. Next, a step of subjecting the PVA molecules of the PVA layer to cross-linking treatment is carried out, that is, the colored layered body is immersed in a boric acid cross-linked aqueous solution at 30 ° C for 60 seconds to adsorb iodine. The aqueous solution of boric acid cross-linking in this step is such that the boric acid content is 3 parts by weight based on 100 parts by weight of water, and the potassium iodide content is 3 parts by weight based on 100 parts by weight of water.

Then, the obtained colored laminate was stretched by 3.05 times (extension in boric acid water) in an aqueous solution of boric acid at an elongation temperature of 70 ° C in the same direction as in the previous air to obtain an optical film having a final stretching ratio of 5.50 times. Laminated body. The optical film laminate was taken out from the aqueous boric acid solution, and boric acid adhering to the surface of the PVA layer was washed with an aqueous solution having a potassium iodide content of 4 parts by weight based on 100 parts by weight of water. The washed optical film laminate was dried by a drying step of warm air at 60 °C. The thickness of the polarizing film contained in the obtained optical film laminate was 5 μm.

[Protective film] The protective film is obtained by extruding a methacrylic resin pellet having a glutaryleneimine ring unit into a film shape and then extending it. This protective film is an acrylic film having a thickness of 20 μm and a moisture permeability of 160 g/m ² .

Next, the polarizing film and the protective film were bonded together using an adhesive agent shown below to prepare a polarizing film.

The above-mentioned adhesive (active energy ray-curable adhesive) was prepared by mixing the components according to the blending table described in Table 1, and stirring at 50 ° C for 1 hour to prepare an adhesive (active energy ray-curable adhesive A) . The numerical values in the table show the weight % when the total amount of the composition is set to 100% by weight. The ingredients used are as follows. HEAA: hydroxyethyl acrylamide M-220: ARONIX M-220, tripropylene glycol diacrylate), manufactured by Toagosei Co., Ltd. ACMO: N-propylene fluorenyl phenylephrine AAEM: 2-acetamethylene ethoxyethyl Methacrylate, UP-1190, manufactured by Nippon Synthetic Chemical Co., Ltd.: ARUFON UP-1190, manufactured by Toagosei Co., Ltd. IRG907: IRGACURE 907, 2-methyl-1-(4-methylthiophenyl)-2-i-Folin -1-ketone, DETX-S manufactured by BASF Corporation: KAYACURE DETX-S, diethyl 9-oxosulfur , Japan Chemical Pharmaceutical Co., Ltd.

[Table 1]

Further, in the examples and comparative examples in which the above-mentioned adhesive was used, the protective film and the polarizing film were laminated by the adhesive, and then the ultraviolet ray was applied to cure the adhesive to form an adhesive layer. For the ultraviolet irradiation, a metal halide lamp filled with gallium (manufactured by Fusion UV Systems, Inc., trade name "Light HAMMER 10", bulb: V bulb, peak illuminance: 1600 mW/cm ² , cumulative irradiation amount 1000/mJ/cm ² ( Wavelength 380~440nm).

[Retardation film] The retardation film (1/4 wavelength phase difference plate) of the present embodiment is a retardation layer for a quarter-wavelength plate and a retardation layer for a half-wavelength plate which are oriented and fixed by a liquid crystal material. The retardation film composed of these two layers. Specifically, it is manufactured according to the following procedure.

(Liquid Crystal Material) A material for forming a phase difference layer for a half-wavelength plate and a retardation layer for a quarter-wave plate is a polymerizable liquid crystal material having a nematic liquid crystal phase (manufactured by BASF Corporation: trade name Paliocolor LC242) ). A photopolymerization initiator (manufactured by BASF Corporation, trade name Irgacure 907) used for the polymerizable liquid crystal material was dissolved in toluene. In order to improve the coating property, the MEGAFACE series of DIC is added to the liquid crystal coating liquid by adding 0.1 to 0.5% of the thickness of the liquid crystal. The liquid crystal coating liquid was applied onto a oriented substrate by a bar coater, and then dried by heating at 90 ° C for 2 minutes, and then directionally fixed by ultraviolet light curing under a nitrogen atmosphere. For the substrate, for example, PET can be used to transfer the liquid crystal coating layer afterwards. In order to improve the coating property, the fluoropolymer of the MEGAFACE series of DIC is added to the thickness of the liquid crystal layer by 0.1% to 0.5%, and MIBK (methyl isobutyl ketone), cyclohexanone or MIBK and ring are used. A mixed solvent of ketone was dissolved to a solid concentration of 25% to prepare a coating liquid. The coating liquid was applied to a substrate with a wire bar, and dried by ultraviolet curing in a nitrogen atmosphere at a temperature of 65 ° C for 3 minutes. For the substrate, for example, PET can be used to transfer the liquid crystal coating layer afterwards.

(Manufacturing Step) The manufacturing steps of this embodiment will be described with reference to Fig. 7 . In addition, the numbers in Figure 7 are different from the numbers in the other figures. This manufacturing step 20 provides the substrate 14 with a roll and supplies the substrate 14 from the supply reel 21. In the manufacturing step 20, the coating liquid of the ultraviolet curable resin 10 is applied onto the substrate 14 by the die 22 . In the manufacturing step 20, the roll plate 30 is a cylindrical mold for forming a concave-convex shape of the alignment film for a quarter-wavelength plate having a quarter-wavelength retardation plate formed on the circumferential side surface thereof. In the manufacturing step 20, the substrate 14 to which the ultraviolet curable resin has been applied is pressed against the circumferential side surface of the roll plate 30 by the pressure roller 24, and ultraviolet irradiation is performed by the ultraviolet irradiation device 25 composed of a high pressure mercury lamp to obtain ultraviolet curability. The resin is hardened. Thereby, the manufacturing step 20 transfers the uneven shape formed on the circumferential side surface of the roll plate 30 so as to be transferred to the base material 14 at 75° in the MD direction. Thereafter, the base material 14 and the cured ultraviolet curable resin 10 are peeled off from the roll plate 30 in an integrated state by the peeling roller 26, and then the liquid crystal material is applied by the die 29. Thereafter, the liquid crystal material is cured by ultraviolet irradiation by the ultraviolet irradiation device 27, and the retardation layer for the quarter-wavelength plate is formed by these procedures. Next, in the step 20, the substrate 14 is transported to the die 32 by the transport roller 31, and the ultraviolet curable resin 12 is coated on the retardation layer of the quarter-wave plate of the substrate 14 by the die 32. Cloth liquid. In the manufacturing step 20, the roll plate 40 is a cylindrical forming mold, and the uneven side shape of the 1/2 wavelength plate oriented film for the 1/4 wavelength retardation plate is formed on the circumferential side surface. In the manufacturing step 20, the base material 14 to which the ultraviolet curable resin has been applied is pressed against the circumferential side surface of the roll plate 40 by the pressure roller 34, and ultraviolet irradiation is performed by the ultraviolet irradiation device 35 composed of a high pressure mercury lamp to obtain ultraviolet curability. The resin is hardened. Thereby, the manufacturing step 20 transfers the uneven shape formed on the circumferential side surface of the roll plate 40 so as to be transferred to the substrate 14 at 15° in the MD direction. Thereafter, the base material 14 and the cured ultraviolet curable resin 12 are peeled off from the roll plate 40 in an integrated state by the peeling roller 36, and then the liquid crystal material is applied by the die 39. After that, the ultraviolet ray irradiation device 37 performs ultraviolet ray irradiation to cure the liquid crystal material, and the program is used to form a phase difference layer for the 1/2 wavelength plate, thereby producing a retardation layer for the 1/4 wavelength plate. A retardation film having a thickness of 7 μm composed of two layers of a retardation layer for a half-wavelength plate.

[Optical film (optical laminate)] The retardation film obtained by the above procedure and the polarizing film obtained by the above procedure were successively bonded by a roll to roll method using the above-mentioned adhesive. A laminated film (optical laminate) was produced by setting the axial angle of the slow axis and the absorption axis to 45°.

[Second Adhesive Layer] <Preparation of (meth)acrylic polymer A1> 99 parts by weight of acrylic acid butyl ester (BA) and acrylic acid were fed to a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler. 4-hydroxybutyl ester (HBA) 1 part by weight of a monomer mixture. 0.1 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was fed together with ethyl acetate, and slowly stirred with respect to 100 parts by weight of the above monomer mixture (solid content). After introducing nitrogen gas for nitrogen substitution, the liquid temperature in the flask was maintained at around 55 ° C for 7 hours. Thereafter, ethyl acetate was added to the obtained reaction liquid to prepare a solution of the (meth)acrylic polymer A1 having a solid content of 30% and a weight average molecular weight of 1.6 million.

<Preparation of Acrylic Adhesive Composition> An isocyanate crosslinking agent (trade name: TAKENATE D110N, trimethylolpropane) is blended with respect to 100 parts by weight of the solid component of the obtained (meth)acrylic polymer A1 solution. 0.1 parts by weight of a benzoic acid benzoate (trade name: NYPER BMT, manufactured by Nippon Oil & Fats Co., Ltd.) of 0.1 part by weight of a peroxide cross-linking agent, manufactured by Mitsui Chemicals Co., Ltd. An acrylic adhesive composition was prepared by dissolving 0.3 parts by weight of a decane coupling agent (trade name: A-100, manufactured by K.K.).

<Production of Optical Laminate with Adhesive Layer> The acrylic adhesive composition was uniformly applied to a polyethylene terephthalate having a thickness of 75 μm treated with a polyfluorene-based release agent by a spray coater. The surface of the ester film (separator) was dried in an air circulating oven at 155 ° C for 2 minutes to form a second adhesive layer having a thickness of 70 μm on the surface of the separator. Next, the separator in which the second adhesive layer was formed was transferred to the protective film side of the obtained optical laminate (which had been subjected to corona treatment) to prepare an optical laminate having an adhesive layer.

[First Adhesive Layer] The first adhesive layer was formed in the same manner as the above-described second adhesive layer, and the first adhesive layer was formed according to the blending contents of Tables 2 and 3 to form a first adhesive layer having a thickness of 50 μm. The separator having the first adhesive layer was transferred to a surface of a polyimide film (PI film, manufactured by DU PONT-TORAY, Kapton 300V, substrate) having a thickness of 75 μm (which has been subjected to corona treatment), and A PI film with an adhesive layer was produced.

[Third Adhesive Layer] The third adhesive layer is formed in the same manner as the above-described second adhesive layer, and the third adhesive layer is formed according to the blending contents of Tables 2 and 3 to form a third adhesive layer having a thickness of 50 μm. The separator having the third adhesive layer is transferred to a surface of a PET film (transparent substrate, manufactured by Mitsubishi Resin Co., Ltd., trade name: DIAFOIL) having a thickness of 125 μm (which has been subjected to corona treatment) to prepare an adhesive. Layer of PET film.

<Laminate for Flexible Image Display Device> As shown in Fig. 6, the first to third adhesive layers (together with each transparent substrate) obtained by the above procedure are used as a transparent substrate 8 having a thickness of 25 μm. The PET film of -1 is bonded to the second adhesive layer 12-2, and the third adhesive layer 12-3 is bonded to the retardation film 3, and the transparent substrate to which the second adhesive layer 12-2 is attached is attached. 8-1 (PET film) The first adhesive layer 12-1 was bonded to each other to fabricate a laminate 11 for a flexible image display device used in the examples.

<Preparation of Acrylic Oligomer (Oligomer B1)> 95 parts by weight of butyl acrylate (BA) and 2 parts by weight of acrylic acid (AA) were fed to a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler. 3 parts by weight of methyl acrylate (MA), 0.1 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 140 parts by weight of toluene, and sufficiently introduced while introducing nitrogen gas while stirring slowly After the nitrogen substitution, the liquid temperature in the flask was maintained at around 70 ° C for 8 hours to prepare a solution of the acrylic oligomer (oligomer B1). The above oligomer VIII had a weight average molecular weight of 4,500. The obtained oligomer B1 is added to a predetermined amount by mixing a crosslinking agent or the like to prepare an acrylic pressure-sensitive adhesive composition.

[Examples 2 to 10 and Comparative Examples 1 to 4] When preparing a polymer ((meth)acrylic polymer), an acrylic oligomer, an adhesive composition, and an adhesive layer to be used, In the same manner as in the first embodiment, a laminate for a flexible image display device was produced, except that it was changed to the above-described Tables 2 to 3.

[Examples 11 to 15 and Example 20] The monomer mixture shown in Table 2 and the photopolymerization initiator 2,2-dimethoxy-1,2-diphenylethan-1-one (commercial product) 0.05 parts by weight of each of the "IRGACURE 651" (manufactured by BASF Japan Co., Ltd.) and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name "IRGACURE 184", manufactured by BASF Japan Co., Ltd.) was placed in a four-necked flask. The ultraviolet ray was irradiated under a nitrogen atmosphere until the viscosity (BH viscometer No. 5 rotor, 10 rpm, temperature 30 ° C) reached about 15 Pa·s, and photopolymerization was carried out to obtain a partially polymerized monomer slurry (monomer component). Part of the polymer) A2 ~ A6. 1,6-hexanediol diacrylate (trade name "A-HD-N", manufactured by Shin-Nakamura Chemical Co., Ltd., HDDA, was uniformly mixed in 100 parts by weight of the obtained polymerized monomer slurry. Polyfunctional monomer) 0.3 parts by weight, and photopolymerization initiator 2,2-dimethoxy-1,2-diphenylethan-1-one (trade name "IRGACURE 651", BASF Japan Co., Ltd. In an amount of 0.3 parts by weight of a ketone coupling agent (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.), 0.3 parts by weight of a starting agent) was added to prepare an acrylic pressure-sensitive adhesive composition.

[Examples 16 to 19] In Examples 16 to 19, in the same manner as in Examples 11 to 15 and Example 20, a partially polymerized monomer slurry (partial polymer of a monomer component) was obtained as shown in Table 2. A6 and A8. Further, in the same manner as in Examples 11 to 15 and Example 20 (the blending amount of the photopolymerization initiator and the decane coupling agent, etc.), acrylic acid was obtained, except that the contents shown in Table 3 were changed. Adhesive composition. Further, in Examples 16 to 18, N-vinyl-pyrrolidone (NVP) blended in the amount shown in Table 3 was further mixed in 100 parts by weight of the above-mentioned partially polymerized monomer slurry A6 to obtain an acrylic adhesive. Agent composition. Further, in Example 19, the NVP was first mixed in the preparation of the monomer mixture, and then the partially polymerized monomer slurry A8 was prepared to obtain an acrylic pressure-sensitive adhesive composition.

The acrylic pressure-sensitive adhesive composition used in the examples 11 to 20 was applied to a release film (trade name "MRF #38", manufactured by Mitsubishi Plastics Co., Ltd.) so that the thickness of the pressure-sensitive adhesive layer was 70 μm. On the surface after the release treatment, an adhesive composition layer was formed, and then a release film (trade name "MRN#38", manufactured by Mitsubishi Plastics Co., Ltd.) was bonded to the surface of the adhesive composition layer. Thereafter, ultraviolet rays were irradiated under the conditions of an illuminance of 4 mW/cm ² and a light amount of 1200 mJ/cm ^{2 to} photoharden the adhesive composition layer to form an adhesive layer. Then, a second adhesive layer which is protected by the release film on both sides of the adhesive layer was obtained. Next, one of the release films for protecting the second adhesive layer is peeled off, and the release film on which the second adhesive layer is formed is transferred to the protective film side of the optical laminate (the corona has been passed) The optical layered body with the adhesive layer was produced. Next, the first adhesive layer and the third adhesive layer were produced in the same manner as the above-described second adhesive layer, and the laminated system for a flexible image display device was produced in the same manner as in the first embodiment.

Further, all the layers including the adhesive layer used in the examples and the comparative examples were the same thickness as in Example 1. Further, the first to third adhesive layers were prepared by using the same blending contents in each of the examples and the comparative examples.

The abbreviations in Table 2 and Table 3 are as follows. BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate AA: acrylic acid HBA: 4-hydroxybutyl acrylate HEA: 2-hydroxyethyl acrylate iOA: isooctyl acrylate iNA: isodecyl acrylate LA: acrylic laurel Ester MA: methyl acrylate NVP: N-vinyl-pyrrolidone D110N: trimethylolpropane / diisocyanate diester ester adduct (manufactured by Mitsui Chemicals, trade name: TAKENATE D110N) C / L: trihydroxy Methylpropane/toluene diisocyanate (manufactured by Japan Polyurethane Industrial Co., Ltd., trade name: CORONATE L) A-HD-N: 1,6-hexanediol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: A-HD-N) Peroxide: Benzoyl peroxide (manufactured by Nippon Oil & Fats Co., Ltd., trade name: NYPER BMT) IRGACURE 184: Photopolymerization initiator, 1-hydroxy-cyclohexyl-phenyl-ketone (BASF) IRGACURE651: photopolymerization initiator, 2,2-dimethoxy-1,2-diphenylethan-1-one (manufactured by BASF) AIBN: azo polymerization initiator, 2,2 ́- Azobisisobutyronitrile (made by KISHIDA Chemical Co., Ltd.) Irganox1010: antioxidant, neopentyl alcohol = 肆[3-(3',5'-di-tertiary butyl-4'-hydroxyphenyl) Acid ester] (manufactured by BASF Corporation)

[Evaluation] <Measurement of Weight Average Molecular Weight (Mw) of (Meth)Acrylic Polymer and Acrylic Oligomer> Weight average molecular weight of the obtained (meth)acrylic polymer and acrylic oligomer ( Mw) was measured by GPC (gel permeation chromatography).・Analytical device: Tosoh (Tosoh) company, HLC-8120GPC ・Pipe column: Tosoh company, G7000H _XL +GMH _XL +GMH _XL・Pipe size: each 7.8mmφ×30cm 90cm ・Tub column temperature: 40°C・Flow rate: 0.8ml/min ・Injection amount: 100μl ・Solution solution: Tetrahydrofuran ・Detector: Differential refractometer (RI) ・Standard sample: Polystyrene

<Measurement of Gel Fraction of Adhesive Layer> About 0.2 g of the adhesive layer formed on the release film peeling-treated surface after one week after the production was taken as the sample 1. The sample 1 was wrapped in a Teflon (registered trademark) film having a diameter of 0.2 μm (trade name "NTF1122", manufactured by Toki Electric Co., Ltd.), and then tied as a sample 2 with a kite string. The weight of the sample 2 before the test described below was measured and made weight A. Further, the aforementioned weight A is the total weight of the sample 1 (adhesive layer), the Teflon (registered trademark) film, and the kite line. And the total weight of the aforementioned Teflon (registered trademark) film and kite line is the weight B. Then, the aforementioned sample 2 was placed in a 50 ml container filled with ethyl acetate, and allowed to stand at 23 ° C for 1 week. Thereafter, the sample 2 was taken out from the container, and dried at 130 ° C for 2 hours in a dryer to remove ethyl acetate, and the weight of the sample 2 was measured. The weight of the sample 2 after the aforementioned test was measured and made weight C. Then, the gel fraction (% by weight) was calculated from the following formula. Gel fraction (% by weight) = (C-B) / (A-B) × 100

The gel fraction of the adhesive layer is preferably 55 to 90% by weight, preferably 57 to 90% by weight, more preferably 60 to 88% by weight, more preferably 62 to 88% by weight, and particularly preferably 65 to 86% by weight. 70~86% by weight is the best. When the gel fraction of the pressure-sensitive adhesive layer is within the above range, the appearance (adhesive dent, etc.), workability, durability, and flexibility are good, and in particular, it is easy to achieve both flexibility in a normal temperature environment and a high temperature environment. Sex, but the best.

<Measurement Thickness> The thickness of the polarizing film, the retardation film, the protective film, the optical laminate, and the pressure-sensitive adhesive layer was measured using a gauge (manufactured by Mitutoyo Co., Ltd.).

<Measurement of the modulus of the modulus> After the adhesive layer provided on the release film having a thickness of 25 μm was cut into 30 mm × 100 mm, the sample was measured so as not to cause the bubble to flow into a cylindrical shape. The sample was measured for the load-elongation curve under the conditions of 10 mm between the clamps and a tensile speed of 300 mm/min using a TENSILON type tensile tester, and the elongations were determined from the curves to be 100%, 500%, and 700%. Stress at modulus (N/mm ² ). Here, the elongation of 100% means a state in which the distance between the jigs is 20 mm, the elongation of 500% means that the distance between the jigs is 60 mm, and the elongation of 700% means a state in which the distance between the jigs is 80 mm.

<Fold-Resistance (Continuous Flexural) Test Method> FIGS. 5(A) and (B) are schematic diagrams showing a flexural test by a U-shaped stretching tester (YUASA SYSTEM Machine Co., Ltd.). The foregoing testing machine can change the bending of the planar workpiece in a U-shaped 180° bending state in a U-shaped manner in a non-loading state, which can change the bending by adjusting the distance between the faces bent into U-shapes. radius. In the test, the laminated body for a flexible image display device of 2.5 cm × 10 cm obtained in each of the examples and the comparative examples was placed in a test machine so as to be bendable in the longitudinal direction, and (i) 25 ° C × 50% RH, (ii) 70 ° C, and a part of the examples (Example 11 and the like) are at (iii) 85 ° C and (iv) 60 ° C × 95% RH, at a bending angle of 180 °, a bending radius of 3 mm, The evaluation was carried out under the conditions of a bending speed of 1 second/time. Further, the sample for measurement (evaluation) was constructed as shown in FIG. 6, and the transparent substrate 8-2 (PET film) was a concave side (inner side) and the substrate 9 (PI film) was a convex side ( The outer side is evaluated after being bent in the longitudinal direction near the center. The folding strength was evaluated up to the number of times until the flexure of the laminate for the flexible image display device was broken or peeled off between the layers. Here, the test is terminated when the number of bends reaches 200,000 times. Further, under the conditions (i) and (ii) above, it is preferable that there is no problem in practical use, and if it is practically problem-free under the conditions (iii) and (iv) above, even under more severe conditions. It is also preferred to maintain product stability. <With or without peeling and cracking> ◎: 200,000 times or more and no defects (no problem in practical use) ○: 100,000 to less than 200,000 times and defective (practical problem) △: 50,000 to less than 100,000 Bad and bad (practical problem) ×: less than 50,000 times and bad (practical problem)

<Adhesion (adhesion)> The surface of the adhesive layer of the separator in which the second adhesive layer was formed, which was obtained in a part of the examples (Example 11 and the like), was bonded to a polyethylene terephthalate having a thickness of 25 μm. A diester (PET) film was cut into 25 mm width as a test piece. Then, the glass plate having a thickness of 1 mm after being purified by isopropyl alcohol was bonded to each film by a double-sided adhesive tape (trade name: No. 5000 NS manufacturing company name: Nitto Denko) (optical thickness 75 μm, thickness 25 μm optical) On the side of the protective film of the laminate, PET having a thickness of 125 μm, a adherend for adhesion evaluation was prepared. Next, after separating the separator of the test piece, a 2 kg roller was reciprocated to adhere the surface of the pressure-sensitive adhesive layer of the test piece to each of the above-mentioned films (PI, polarizing film side of optical laminate, PET). After attaching the surface of the adhesive layer to each of the films (PI, polarizing film side of the optical laminate, PET), one end of the test piece (adhesive layer and PET film) after being left at 23 ° C for 30 minutes was 300 mm / The speed of the minute was peeled off in the peeling direction of 180 degrees, and the adhesion (resistance) to the adherend at this time was measured as the adhesion (unit: N/25 mm). Further, the above-mentioned adhesion force (N/25 mm) is preferably 2.0 N/25 mm or more, 2.5 N/25 mm or more, and more preferably 3.0 N/25 mm or more from the viewpoint of preventing peeling off during repeated bending.

[Table 2]

[table 3]

[Table 4]

[table 5]

[Table 6]

From the evaluation results of Tables 4 and 5, it was confirmed that the stress of the 100% modulus of the adhesive layer of all the examples was 0.01 to 0.1 N/mm ² , and the stress of 500% modulus was 0.05 to 0.2 N/mm. ² , and through the folding endurance (continuous flexural) test, even when exposed to normal temperature (25 ° C × 50% RH) or high temperature (70 ° C) environment, it is practically no problem in cracking (breaking) or peeling The extent of the problem. In other words, it can be confirmed that the laminate for a flexible image display device of each embodiment can be made to face the reverse deflection without cracking or breaking by using an adhesive layer having a modulus of a desired range. A laminate for a flexible image display device having excellent flexibility and adhesion. Further, from the evaluation results of Tables 5 and 6, it was confirmed that Examples 16 to 18 used an acrylic adhesive composition which was obtained by additionally mixing a monomer containing a guanamine group after modulating a monomer slurry and performing partial polymerization. The adhesive layer was prepared, and Example 19 used an adhesive layer prepared by blending an acrylic adhesive composition containing a guanamine group-containing monomer in the preparation of a monomer slurry, so that even in a high temperature environment (85 ° C) or high temperature, high humidity environment (60 ° C × 95% RH) under severe conditions, in the face of repeated deflection, it will not crack or peel off and has excellent adhesion.

On the other hand, it can be confirmed that in Comparative Examples 1 to 4, since the stress of 500% modulus does not fall within the desired range, it is tested by the folding endurance (continuous deflection) test, and when it is exposed to a normal temperature or a high temperature environment, Cracking (breaking) or spalling is a practically problematic aspect, and any aspect of flexing resistance or adhesion is poor. In particular, it was confirmed that the stress of the 100% modulus of Comparative Example 1 did not fall within the desired range, so that the flex resistance and the adhesion were extremely poor.

1‧‧‧ polarizing film

2, 2-1, 2-2‧‧‧ protective film

3‧‧‧ phase difference layer

4-1, 4-2‧‧‧ Transparent conductive film

5-1, 5-2‧‧‧ base film

6, 6-1, 6-2‧‧‧ transparent conductive layer

7‧‧‧Parts

8‧‧‧Transparent substrate

8-1, 8-2‧‧‧ Transparent substrate (PET film)

9‧‧‧Substrate (PI film)

10‧‧‧Organic EL display panel

10‧‧‧(Fig. 7) UV curable resin

10-1‧‧‧Organic EL display panel (with touch sensor)

11‧‧‧Laminated body for flexible image display device (layered body for organic EL display device)

12‧‧‧Adhesive layer

12‧‧‧(Fig. 7) UV curable resin

12-1‧‧‧1st adhesive layer

12-2‧‧‧2nd adhesive layer

12-3‧‧‧3rd adhesive layer

13‧‧‧Decorative printed film

14‧‧‧Double adhesive tape

14‧‧‧(Fig. 7) Substrate

20‧‧‧Optical laminate

20‧‧‧(Fig. 7) Manufacturing steps

21‧‧‧(Figure 7) Supply reel

22, 29, 32, 39‧ ‧ (Fig. 7) die

24, 34‧‧ (Figure 7) pressure roller

25, 27, 35, 37‧ ‧ (Fig. 7) ultraviolet irradiation device

26, 36‧‧ (Figure 7) peeling roller

30‧‧‧Touch panel

30, 40‧‧‧(Fig. 7) Roller Edition

31‧‧‧(Fig. 7) conveyor roller

40‧‧‧Window

100‧‧‧Flexible image display device (organic EL display device)

P‧‧‧Flex point

UV‧‧‧UV irradiation

L‧‧‧Liquid Crystal Materials

Fig. 1 is a cross-sectional view showing a conventional organic EL display device. Fig. 2 is a cross-sectional view showing a flexible image display device according to an embodiment of the present invention. Fig. 3 is a cross-sectional view showing a flexible image display device according to another embodiment of the present invention. Fig. 4 is a cross-sectional view showing a flexible image display device according to another embodiment of the present invention. Fig. 5 is a view showing a flexural test ((A) bending angle 0°, (B) bending angle 180°). Figure 6 is a cross-sectional view showing a sample for evaluation used in the examples. Fig. 7 is a view showing a manufacturing method of the phase difference used in the embodiment.

Claims (7)

A laminated body for a flexible image display device, comprising: an adhesive layer and an optical film containing at least a polarizing film; and a stress of 100% modulus of the adhesive layer is 0.01 to 0.1 N/mm ² , and the foregoing The stress of the 500% modulus of the adhesive layer is 0.05 to 0.2 N/mm ² . The laminate for a flexible image display device according to claim 1, wherein the adhesive layer has a gel fraction of 55 to 90% by weight. The laminate for a flexible image display device according to claim 1 or 2, which has two or more layers and five or less layers of the above-mentioned adhesive layer. The laminate for a flexible image display device according to any one of claims 1 to 3, wherein a stress of a 100% modulus of the adhesive layer is 0.01 to 0.08 N/mm ² . The laminate for a flexible image display device according to any one of claims 1 to 4, wherein a stress of a 500% modulus of the adhesive layer is 0.085 to 0.2 N/mm ² . A flexible image display device comprising the laminate for a flexible image display device according to any one of claims 1 to 5, and an organic EL display panel, wherein the organic EL display panel is disposed on the viewing side The laminated body for a flexible image display device. The flexible video display device of claim 6, wherein a window is disposed on the viewing side of the laminated body for the flexible video display device.