TW202027997A - Optical laminate and display - Google Patents

Abstract

The present invention relates to an optical laminate having a front plate and one or more adhesive layers, and more specifically, to an optical laminate capable of suppressing distortion of a reflected image reflected on a surface of the front plate, and a displaying device including the same. The optical laminate sequentially comprises: a front plate; an adhesive layer (A); an polarizer layer; an n-layer (n represents any integer of 0 or more) adhesive layer (B); and a supporting substrate. The optical laminate is satisfied with a formula of 0.2 ≤ T/C(total), wherein T represents a thickness ([mu]m) of the front plate, and C(total) represents the sum of creep C (%) of each adhesive layer arranged between the front plate and the supporting substrate at 25 DEG C.

Description

Optical laminate and display device

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

As various display devices such as a liquid crystal display device and an organic electroluminescence (EL) display device, it is known to have a configuration in which a front panel is provided on the outermost surface of the viewing side to protect the screen.

For example, International Publication No. 2017/204228 (Patent Document 1) states that a laminate including a resin film having a specific surface roughness and an adhesive layer arranged on one surface and having a specific loss tangent is applied to the above-mentioned front panel . [Prior Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2017/204228

[The problem to be solved by the invention]

Sometimes the front panel is made into a laminate with one or more other optical members and incorporated on the visible side of the display element (liquid crystal cell, organic EL display element, etc.) included in the display device. Usually, the front panel, the other optical member mentioned above, and the other optical member mentioned above are laminated|stacked via an adhesive layer or an adhesive layer. In the above-mentioned laminate that includes a front panel and includes more than one adhesive layer, when the reflected image reflected on the surface is observed from the front panel, it is found that the reflected image is distorted. The laminated body that produces such distortion of the reflected image may reduce the visibility of the screen of the display device.

The object of the present invention is to provide an optical laminate and a display device including the optical laminate. The optical laminate includes a front panel and one or more adhesive layers and suppresses the distortion of the reflected image reflected on the surface of the front panel. [Technical means to solve the problem]

The present invention provides the optical laminate display device shown below. [1] An optical laminate comprising a front panel, an adhesive layer (A), a polarizing element layer, n layers [n represents any integer greater than 0] an adhesive layer (B), and a supporting substrate, and Satisfies the following formula (1): 0.2≦T/C _total (1) [In formula (1), T represents the thickness of the front panel [μm]; C _total represents the arrangement between the front panel and the supporting substrate The total creep value C[%] of each adhesive layer at 25℃]. [2] The optical laminate as described in [1], which further satisfies the following formula (2): T/C _total ≦1.2 (2) [In formula (2), T and C _{total have} the same meaning as above] . [3] The optical laminate according to [1] or [2], wherein the above-mentioned n is any integer of 1 or more. [4] The optical laminate according to any one of [1] to [3], which further includes one or more retardation layers arranged between the polarizing element layer and the supporting substrate. [5] The optical laminate according to [4], wherein the retardation layer includes a cured product of a polymerizable liquid crystal compound. [6] The optical laminate according to any one of [1] to [5], wherein the polarizing element layer includes a cured product of a polymerizable liquid crystal compound. [7] A display device comprising the optical laminate as described in any one of [1] to [6]. [Effects of Invention]

The present invention can provide an optical laminate and a display device including the optical laminate. The optical laminate includes a front panel and one or more adhesive layers and suppresses the distortion of a reflected image reflected on the surface of the front panel.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all the following drawings, the scales are adjusted appropriately for easy understanding of each component. The scale of each component shown in the drawings may not be the same as the scale of the actual component.

In this specification, the meanings or definitions of the following terms are as follows. The term "optical laminate" refers to a laminate composed of two or more layers used in optical devices such as display devices. The two or more layers constituting the optical layered body may be independently formed as a plate, a sheet, a film, a coating layer formed by a step including a coating liquid for forming a coating layer, and the like. Examples of display devices include image display devices such as liquid crystal display devices and organic EL display devices. The optical laminate of the present invention sequentially includes a front panel, an adhesive layer (A), a polarizing element layer, n layers [n represents any integer greater than 0] an adhesive layer (B), and a supporting substrate. The optical laminate of the present invention is arranged on the display element (liquid crystal cell, organic EL display element, inorganic EL display element, plasma display) of the display device with the front panel facing outward (the side opposite to the display element side, that is, the visible side) Components, field emission display components, etc.).

The so-called "adhesive layer" refers to a layer composed of an adhesive or a layer formed by applying a certain treatment to the layer. The so-called "adhesive" refers to those also known as pressure-sensitive adhesives. In this specification, the so-called "adhesive" refers to adhesives other than adhesives (pressure-sensitive adhesives), and is clearly distinguished from adhesives. The so-called "adhesive layer" refers to a layer composed of an adhesive or a layer formed by applying a certain treatment to the layer. The adhesive layer and the adhesive layer can also be clearly distinguished in terms of physical properties. For example, when the storage modulus is listed as the physical property, the adhesive layer generally shows a storage modulus below 5.0 MPa at 25°C, and the adhesive layer shows a storage modulus above 500 MPa at 25°C.

The so-called adhesive layer (A) refers to the adhesive layer disposed between the front panel and the polarizing element layer. The optical laminate may include one or more adhesive layers as the adhesive layer (A), and preferably one layer. The so-called adhesive layer (B) refers to the adhesive layer disposed between the polarizing element layer and the supporting substrate. The optical laminate may not include the adhesive layer (B), and may include one or more adhesive layers as the adhesive layer (B).

The so-called "front panel" refers to a member arranged on the outermost surface of the optical laminate (the outermost surface on the visible side). In this specification, the "front panel" is not limited to the case where the member is a plate, and may be a sheet or film.

The so-called "(meth)acrylic acid" means at least one selected from the group consisting of acrylic acid and methacrylic acid. Other terms with "(methyl)" are also the same.

The term "bendable" means that when at least one direction in the plane of the optical layered body is bent so that the radius of curvature of the inner surface of the optical layered body becomes 1 mm, it can be bent without cracking. When the optical layered body is repeatedly bent so that the radius of curvature of the inner surface of the optical layered body becomes 1 mm with respect to at least one direction in the plane, it is preferable that no cracks occur even if the number of bendings is 10,000 times.

＜Optical laminated body＞ [1] Outline of the shape and layer composition of the optical laminate The optical laminate of the present invention (hereinafter also referred to as "optical laminate") sequentially includes a front panel, an adhesive layer (A), a polarizing element layer, and n layers [n represents any integer greater than 0] an adhesive layer ( B), and supporting substrate. The adhesive layer (A) is usually one layer. The n representing the number of the adhesive layer (B) may be 0, but is preferably an integer of 1 or more, more preferably an integer of 1 or more and 3 or less, and still more preferably 1 or 2. When n is 2 or more, a plurality of adhesive layers are usually arranged to be separated from each other (separate other layers).

The optical laminate may further include one or more retardation layers. The retardation layer is usually arranged between the polarizing element layer and the supporting substrate. The retardation layer can be laminated on other layers (including other retardation layers) via an adhesive layer or an adhesive layer.

The optical laminate may include other layers than the above-mentioned layers. The other layer can be arranged, for example, between the adhesive layer (A) and the polarizing element layer, between the polarizing element layer and the supporting base material, or arranged on the outer side of the supporting base material (the side opposite to the polarizing element layer side). For example, the optical laminate may include a thermoplastic resin film layer disposed between the adhesive layer (A) and the polarizing element layer. For example, the optical laminate may include, for example, a thermoplastic resin film layer laminated on the surface on the front panel side and/or the surface on the support substrate side in the polarizing element layer via an adhesive layer. In addition, a base film for coating with a coating liquid can be incorporated in the optical laminate together with the above-mentioned layer. For example, the optical laminate may include an adhesive layer (C) arranged on the outer side of the supporting base material. The adhesive layer (C) can be used for bonding to a display element, for example.

The thickness of the optical laminate varies according to the functions required for the optical laminate and the use of the optical laminate, and is therefore not particularly limited. For example, it is 50 μm or more and 1000 μm or less, preferably 100 μm or more and 500 μm or less, and more It is preferably from 100 μm to 300 μm.

The top view shape of the optical laminate may be, for example, a square shape, preferably a square shape having long sides and short sides, and more preferably a rectangular shape. When the top view shape of the optical laminate is rectangular, the length of the long side may be, for example, 10 mm or more and 1400 mm or less, preferably 50 mm or more and 600 mm or less. The length of the short side is, for example, 5 mm or more and 800 mm or less, preferably 30 mm or more and 500 mm or less, and more preferably 50 mm or more and 300 mm or less. When the planar shape of the optical laminate is a square shape, the length of each side in each layer constituting the optical laminate may be the same as each other. Each layer constituting the optical layered body may be processed by R processing at the corners, or may be processed by notching the ends, or processed by drilling.

[2] Example of layer composition of optical laminate Fig. 1 is a schematic cross-sectional view showing an example of the optical laminate of the present invention. The optical laminate 1 shown in FIG. 1 includes a front panel 10, a first adhesive layer 20 as an adhesive layer (A), a polarizing element layer 30, and a second adhesive layer 40 as an adhesive layer (B) in this order. , The first retardation layer 50, the third adhesive layer 60 as the adhesive layer (B), the second retardation layer 70, and the support base 80. In the optical laminate 1, an adhesive layer may be used instead of the second adhesive layer 40. In the optical laminate 1, an adhesive layer may be used instead of the third adhesive layer 60. In the optical laminate 1, an adhesive layer may be used instead of the second adhesive layer 40 and an adhesive layer may be used instead of the third adhesive layer 60. The first adhesive layer 20 is preferably directly connected to the front panel 10.

Fig. 2 is a schematic cross-sectional view showing another example of the optical laminate of the present invention. Except for the thermoplastic resin film layer 90 between the first adhesive layer 20 and the polarizing element layer 30, the optical laminate 2 shown in FIG. 2 has the same layer structure as the optical laminate 1 shown in FIG. In the optical laminate 2, an adhesive layer may be used instead of the second adhesive layer 40. In the optical laminate 2, an adhesive layer can be used instead of the third adhesive layer 60. In the optical laminate 2, an adhesive layer may be used instead of the second adhesive layer 40 and an adhesive layer may be used instead of the third adhesive layer 60. The first adhesive layer 20 is preferably directly connected to the front panel 10 and the thermoplastic resin film layer 90. That is, it is preferable that the front panel 10 and the thermoplastic resin film layer 90 are directly joined by the first adhesive layer 20.

[3] Regarding the above formulas (1) and (2) The optical laminate of the present invention satisfies the above formula (1). Thereby, the distortion of the reflected image reflected on the surface of the front panel 10 can be suppressed. In order to suppress the distortion of the reflected image reflected on the surface of the front panel 10, the inventors of the present invention conducted intensive research and found that the distortion of the reflected image and the thickness of the front panel disposed on the outermost side of the optical laminate and the optical laminate contained There is a correlation between the strain characteristics of the adhesive layer when stress is applied; and if the T/C _total in the above formula (1) is above a specific value, the distortion of the reflected image can be effectively suppressed. From the viewpoint of suppressing the distortion of the reflected image, the T/C _total in the above formula (1) is preferably 0.22 or more, more preferably 0.25 or more, and still more preferably 0.30 or more.

On the other hand, from the viewpoint of improving the flexibility of the optical laminate and the display device including the optical laminate, the optical laminate of the present invention preferably satisfies the above formula (2). From the viewpoint of improving the flexibility of the optical laminate and the display device including the optical laminate, the T/C _total in the above formula (2) is more preferably 1.18 or less, more preferably 1.15 or less, and still more preferably 1.10 or less.

As described above, when the optical layered body is repeatedly bent with respect to at least one direction in its plane such that the radius of curvature of the inner surface of the optical layered body becomes 1 mm, it is preferable that no bending occurs even if the number of bending is 10,000. Cracked. When the optical laminate is repeatedly bent in such a way that the radius of curvature of the inner surface of the optical laminate becomes 1 mm in at least one direction within its plane, it is more preferable that no cracks occur even if the number of bending is about 50,000. It is more preferable that no cracks occur even if the number of bendings is about 80,000 times, and it is more preferable that no cracks occur even if the number of bendings is about 100,000 times. For the optical laminate, at least one direction in the plane and a direction orthogonal to the direction, the number of times of bending that does not cause cracks during the repeated bending is preferably within the above range. The display device using the optical laminate with good flexibility can be used as a flexible display that can be bent, bent, or wound.

C _total in formula (1) and formula (2) represents the _total creep value C [%] of each adhesive layer disposed between the front panel 10 and the support base 80 at 25°C. The so-called adhesive layer arranged between the front panel 10 and the supporting substrate 80 refers to the adhesive layer corresponding to the adhesive layer (A) or the adhesive layer (B), and does not include the adhesive layer arranged on the outside of the supporting substrate 80 The adhesive layer (C). The creep value C of each adhesive layer at 25°C is measured according to the method described in the following examples.

[4]Front panel The front panel 10 is preferably a plate-shaped body capable of transmitting light. The front panel 10 may be composed of only one layer, or may be composed of two or more layers. As the front panel 10, for example, a plate-shaped body made of glass (for example, a glass plate, glass film, etc.) and a plate-shaped body made of resin (for example, a resin plate, a resin sheet, a resin film, etc.) can be cited. Among the above, from the viewpoint of the flexibility of the optical laminate and the display device including the optical laminate, a plate-shaped body made of resin such as a resin film is preferred. In addition, when a plate-shaped body made of glass is used, the problem of distortion of the reflected image is not likely to occur originally, but it also depends on the thickness.

As the thermoplastic resin constituting the plate-shaped body made of resin such as resin film, for example, chain polyolefin resin (polyethylene resin, polypropylene resin, polymethylpentene resin, etc.), cyclic polyolefin Polyolefin resins (Norene resins, etc.); cellulose resins such as triacetyl cellulose; polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate Polyester resins such as diesters; polycarbonate resins; ethylene-vinyl acetate resins; polystyrene resins; polyamide resins; polyether imine resins; polymethyl (meth)acrylate (Meth)acrylic resins such as resins; polyimide-based resins; polyether-based resins; poly-based resins; polyvinyl chloride-based resins; polyvinylidene chloride-based resins; polyvinyl alcohol-based resins; polyethylene Alkyd resin; polyether ketone resin; polyether ether ketone resin; polyether ether resin; polyamide imine resin, etc. The thermoplastic resin can be used alone or in combination of two or more kinds. Among them, in terms of flexibility, strength, and transparency, as the thermoplastic resin constituting the front panel 10, polyimide resins, polyimide resins, and polyimide imide resins can be used well. .

The front panel 10 may also be a film in which a hard coat is provided on at least one surface of the base film to further increase the hardness. As the base film, the above-mentioned resin film can be used. The hard coat layer can be formed on one side of the base film or on both sides. By providing a hard coat, the hardness and scratch resistance can be improved. The hard coat layer is, for example, a cured layer of ultraviolet curable resin. Examples of ultraviolet curable resins include (meth)acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins. In order to increase strength, the hard coat layer may contain additives. The additives are not limited, and examples include inorganic fine particles, organic fine particles, or a mixture of these.

The front panel 10 not only has the function of protecting the front surface (screen) of the display device (as a window film), but also has the function as a touch sensor, blue light blocking function, viewing angle adjustment function, etc.

The thickness T of the front panel 10 is appropriately selected to satisfy the aforementioned formula (1), and preferably further satisfy the aforementioned formula (2). The thickness T of the front panel 10 is preferably 20 μm or more and 2000 μm or less, and more preferably 25 μm, from the viewpoint of suppression of distortion of the reflected image and the flexibility of the optical laminate and the display device including the optical laminate The above 1500 μm or less, more preferably 30 μm or more and 1000 μm or less, may also be 40 μm or more and 500 μm or less, furthermore may be 40 μm or more and 200 μm or less, and further may be 40 μm or more and 100 μm or less.

From the viewpoint of the suppression of the distortion of the reflected image and the flexibility of the optical laminate and the display device including the optical laminate, the tensile elastic modulus of the front panel 10 is preferably 2.0 GPa or more and 10.0 GPa or less, more preferably It is 3.0 GPa or more and 9 GPa or less, more preferably 4.0 GPa or more and 8.0 GPa or less. The tensile elastic modulus of the front panel 10 is measured under the following conditions. Measurement environment: temperature 23℃, relative humidity 55%RH Sample size: width: 4 mm, length: 110 mm (length direction = stretching direction) Stretching speed: 4 mm/min.

[5] Adhesive layer (A) The adhesive layer (A) is an adhesive layer disposed between the front panel 10 and the polarizing element layer 30. In the optical laminates 1 and 2 shown in FIGS. 1 and 2, the first adhesive layer 20 corresponds to the Adhesive layer (A). The optical laminate may include one or more adhesive layers as the adhesive layer (A), and preferably one layer.

The adhesive layer (A) may be composed of an adhesive composition with (meth)acrylic, rubber, urethane, ester, silicone, polyvinyl ether resin as a main component. Among them, an adhesive composition using a (meth)acrylic resin excellent in transparency, weather resistance, heat resistance, etc., as a base polymer is preferred. The adhesive composition may be an active energy ray hardening type or a heat hardening type.

As the (meth)acrylic resin (base polymer) used in the adhesive composition, for example, butyl (meth)acrylate, methyl (meth)acrylate, and ethyl (meth)acrylate can be used well. , Hexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, 2-(meth)acrylate A polymer or copolymer in which one or two or more (meth)acrylates such as ethylhexyl ester and iso-(meth)acrylate are used as monomers. Preferably, a polar monomer is copolymerized with the base polymer. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, (meth)acrylic acid N, N -Monomers such as dimethylaminoethyl and glycidyl (meth)acrylate having carboxyl groups, hydroxyl groups, amide groups, amine groups, epoxy groups and the like.

The adhesive composition may contain only the above-mentioned base polymer, but usually further contains a crosslinking agent. As the crosslinking agent, there can be exemplified: a metal ion with a valence of more than 2 that forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound that forms an amide bond with a carboxyl group; a polyepoxy compound that forms an ester bond with a carboxyl group Or polyols; and polyisocyanate compounds that form amide bonds with carboxyl groups. Among them, polyisocyanate compounds are preferred.

The so-called active energy ray curable adhesive composition refers to an adhesive composition having the following properties: it is cured by irradiation of active energy rays such as ultraviolet rays or electron beams, and it is also adhesive before the active energy rays are irradiated. It can be in close contact with adherends such as films, and is cured by irradiation of active energy rays, so that the adhesion can be adjusted. The active energy ray curable adhesive composition is preferably an ultraviolet curable adhesive composition. In addition to the base polymer and the crosslinking agent, the active energy ray curable adhesive composition further contains an active energy ray polymerizable compound. Furthermore, if necessary, a photopolymerization initiator, photosensitizer, etc. may be contained. As the active energy ray polymerizable compound, for example, a (meth)acrylate monomer having at least one (meth)acryloxy group in the molecule; obtained by reacting two or more functional group-containing compounds, and (Meth)acrylic compounds, such as (meth)acrylic acid ester oligomers having at least two (meth)acrylicoxy groups in the molecule, etc.

The adhesive composition may include fine particles, particles (resin particles, glass particles, etc.), glass fibers, resins other than the base polymer, adhesiveness imparting agents, fillers (metal powder or other inorganic powders) to impart light scattering properties Etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, defoamers, corrosion inhibitors, photopolymerization initiators and other additives.

The first adhesive layer 20 (adhesive layer (A)) can be formed by applying, for example, an organic solvent diluent of the above-mentioned adhesive composition on a substrate and drying it. In the case of using an active energy ray-curable adhesive composition, the formed adhesive layer can be irradiated with active energy rays to produce a cured product having a desired degree of curing.

The creep value C of the first adhesive layer 20 (adhesive layer (A)) can be adjusted, for example, by adjusting its thickness or modulus of elasticity, the molecular weight of the base polymer, or the case of using an active energy ray-curable adhesive composition The degree of hardening is controlled. The creep value C of the first adhesive layer 20 (adhesive layer (A)) at 25° C. is, for example, 10% or more and 300% or less, preferably 20% or more and 200% or less, or 100% or less.

The storage modulus of the first adhesive layer 20 (adhesive layer (A)) at 25°C from the viewpoint of the flexibility of the optical laminate and the display device containing the optical laminate, and the suppression of the distortion of the reflected image Generally, it is 0.01 MPa or more and 5 MPa or less, preferably 0.02 MPa or more and 3 MPa or less, more preferably 0.03 MPa or more and 2 MPa or less, and may also be 0.10 MPa or more, or 0.50 MPa or more. The storage modulus of the first adhesive layer 20 (adhesive layer (A)) can be determined by the selection of the material forming the first adhesive layer 20 (adhesive layer (A)), the thickness of the first adhesive layer 20, The manufacturing conditions of the first adhesive layer 20 or a combination of these are adjusted. The storage modulus of the adhesive layer at 25°C is measured according to the method described in the following examples.

The thickness of the first adhesive layer 20 is, for example, 2 μm or more and 100 μm or less, preferably 3 μm or more, from the viewpoint of the adhesion between the layers through the adhesive layer or the control of the creep value C. μm or less, more preferably 5 μm or more and 30 μm or less.

[6] Polarizing element layer Examples of the polarizing element layer 30 include a stretched film or stretched layer that adsorbs a pigment having absorption anisotropy, and a layer formed by coating and curing a pigment having absorption anisotropy. Examples of dyes having absorption anisotropy include dichroic dyes. As the dichroic dye, specifically, iodine or a dichroic organic dye can be used. Dichroic organic dyes include C.I. Direct Red 39 and other dichroic direct dyes composed of bisazo compounds, and dichroic direct dyes composed of compounds such as trisazo and tetrasazo. Examples of the polarizing element layer formed by coating and curing a pigment with absorption anisotropy include coating a composition containing a liquid crystal dichroic pigment or a composition containing a dichroic pigment and a polymerizable liquid crystal and curing it The obtained layer, etc., contains a polarizing element layer of a cured product of a polymerizable liquid crystal compound. The polarizing element layer formed by coating and hardening the pigment with absorbing anisotropy is better than the stretched film or the stretched layer which adsorbs the pigment with absorbing anisotropy because the bending direction is not limited. Therefore, in order to obtain an optical laminate in which at least one direction in the plane and a direction orthogonal to the direction, and further, in all directions in the plane, the number of bendings without cracks during the above-mentioned repeated bending is obtained within the above-mentioned range As the polarizing element layer 30, it is preferable to use a layer obtained by coating and curing a pigment having absorption anisotropy.

[6-1] Polarizing element layer as stretched film or stretched layer The polarizing element layer 30, which is a stretched film for adsorbing pigments with absorption anisotropy, can usually be manufactured through the following steps: uniaxially stretch the polyvinyl alcohol-based resin film; by applying dichroic pigments to the polyvinyl alcohol-based resin film Dyeing and adsorbing the dichroic pigment; treating the polyvinyl alcohol resin film with the dichroic pigment adsorbed with the boric acid aqueous solution; and washing with water after the treatment with the boric acid aqueous solution. The thickness of the polarizing element layer 30 is, for example, 2 μm or more and 40 μm or less. The thickness of the polarizing element layer may be 5 μm or more, and may be 20 μm or less, further may be 15 μm or less, and further may be 10 μm or less.

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

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

The polarizing element layer 30 as an extension layer for adsorbing pigments with absorption anisotropy can usually be manufactured through the following steps: coating a coating solution containing the above-mentioned polyvinyl alcohol-based resin on a base film; making the obtained laminated film Uniaxial stretching; by dyeing the polyvinyl alcohol resin layer of the uniaxially stretched laminated film with dichroic pigments, and adsorbing the dichroic pigments, the polarizing element layer 30 is made; The film of dichroic pigment is treated; and after treatment with an aqueous solution of boric acid, it is washed with water. The base film may be peeled and removed from the polarizing element layer 30 as needed. The material and thickness of the base film may be the same as the material and thickness of the following thermoplastic resin film.

The polarizing element layer 30 as a stretched film or stretched layer can be incorporated in the optical laminate in a form in which a thermoplastic resin film is bonded to one or both surfaces. This thermoplastic resin film can function as a protective film for the polarizing element layer 30 or a retardation film. The thermoplastic resin film may be, for example, polyolefin resins such as chain polyolefin resins (polypropylene resins, etc.), cyclic polyolefin resins (norene resins, etc.); cellulose resins such as triacetyl cellulose. Resins; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate resins; (meth)acrylic resins; or these The mixture of the film. The thickness of the thermoplastic resin film is generally 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less, and still more preferably 60 μm or less from the viewpoint of thinning; , Usually 5 μm or more, preferably 20 μm or more. The thermoplastic resin film may or may not have a phase difference. The thermoplastic resin film can be bonded to the polarizing element layer 30 using an adhesive layer, for example.

[6-2] Polarizing element layer formed by coating and hardening of pigments that absorb anisotropy As the polarizing element layer formed by coating and hardening a pigment with absorption anisotropy, a composition containing a polymerizable dichroic pigment with liquid crystallinity or a composition containing a dichroic pigment and a polymerizable liquid crystal can be used. A polarizing element layer containing a cured product of a polymerizable liquid crystal compound, such as a layer obtained by laying it on a base film (or an alignment film formed on the base film) and curing it. The base film or both the base film and the alignment film may be peeled and removed from the polarizing element layer 30 as needed. The material and thickness of the base film may be the same as the material and thickness of the above-mentioned thermoplastic resin film. The polarizing element layer 30 formed by coating and curing a pigment having an absorbing anisotropy can be incorporated in an optical laminate in a form in which a thermoplastic resin film is attached to one or both surfaces. As the thermoplastic resin film, the same ones as those that can be used for the polarizing element layer of the stretched film or stretched layer can be used. The thermoplastic resin film can be bonded to the polarizing element layer 30 using an adhesive layer, for example. Specific examples of the polarizing element layer 30 formed by coating and curing a pigment having an absorbing anisotropy include those described in JP 2012-33249 A and the like.

The thickness of the polarizing element layer 30 formed by coating and hardening a pigment having absorption anisotropy is generally 10 μm or less, preferably 0.5 μm or more and 8 μm or less, and more preferably 1 μm or more and 5 μm or less.

[7] Adhesive layer (B) The adhesive layer (B) is an adhesive layer disposed between the polarizing element layer 30 and the supporting substrate 80. In the optical laminates 1 and 2 shown in FIGS. 1 and 2, the second adhesive layer 40 and the second 3 The adhesive layer 60 corresponds to the adhesive layer (B). However, it is not limited to these embodiments, and the optical laminate may not include the adhesive layer (B), and may include one or more adhesive layers as the adhesive layer (B). The number of the adhesive layer (B) is preferably 1 or more, more preferably 1 or more and 3 or less, and still more preferably 1 or 2.

Regarding the composition and compounding ingredients of the adhesive composition constituting the adhesive layer (B), the type of the adhesive composition (whether it is an active energy ray hardening type or a thermosetting type, etc.), it can be adjusted to the adhesive layer (B) Additives, manufacturing method of adhesive layer (B), thickness of adhesive layer (B), creep value C and range of adhesive layer (B) at 25°C, and adhesive layer (B) at 25°C The storage modulus and its range below refer to the description of the adhesive layer (A). One or more adhesive layers equivalent to the adhesive layer (B) can be combined with the adhesive layer (A) in terms of thickness, creep value C at 25°C, and storage modulus at 25°C. ) Are the same but may be different. When there are more than two adhesive layers corresponding to the adhesive layer (B), the thickness of the two or more adhesive layers, the creep value C at 25°C, and the storage modulus at 25°C, etc. The aspects can be the same as each other or different.

[8] Support substrate The supporting base 80 is preferably a plate-shaped body capable of transmitting light. The support base 80 may be composed of only one layer, or may be composed of two or more layers. The supporting substrate 80 may also be a display element such as a touch sensor or an organic EL display element. As the supporting substrate 80, similar to the front panel 10, for example, a plate-shaped body made of glass (for example, a glass plate, glass film, etc.), a plate-shaped body made of resin (for example, a resin plate, a resin sheet, a resin film, etc.) ). Among the above, from the viewpoint of the flexibility of the optical laminate and the display device including the optical laminate, a plate-shaped body made of resin such as a resin film is preferred. Regarding specific examples of the thermoplastic resin constituting the resin-made plate-shaped body such as a resin film, the description of the front panel 10 is cited. The thermoplastic resin is preferably a cellulose resin, (meth)acrylic resin, cyclic polyolefin resin, polyester resin, polycarbonate resin, or the like.

The thickness of the supporting substrate 80 is preferably 15 μm or more and 200 μm or less, more preferably 20 μm or more and 150 μm or less, and still more preferably 25 μm or more and 100 μm or less, from the viewpoint of thinning of the optical laminate. It may be 80 μm or less, further may be 60 μm or less, and further may be 50 μm or less.

[9] Retardation layer The optical laminate may further include one layer or two or more retardation layers. The retardation layer is usually arranged between the polarizing element layer 30 and the supporting substrate 80. The retardation layer can be laminated on other layers (including other retardation layers) via an adhesive layer or an adhesive layer. The optical laminates 1 and 2 shown in FIGS. 1 and 2 include a first retardation layer 50 and a second retardation layer 70.

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

The retardation layer formed by curing the polymerizable liquid crystal compound can be formed by applying a composition containing the polymerizable liquid crystal compound to a base film and curing it. An alignment layer can also be formed between the base film and the coating layer. The material and thickness of the base film may be the same as the material and thickness of the above-mentioned thermoplastic resin film. The retardation layer formed by curing the polymerizable liquid crystal compound can be incorporated in the optical laminate in a form having an alignment layer and/or a base film. The supporting substrate 80 may also be a substrate film for coating the above-mentioned composition.

As described above, an adhesive layer or an adhesive layer may be used for the build-up of the retardation layer. This adhesive layer corresponds to the adhesive layer (B). As the adhesive for forming the adhesive layer, a water-based adhesive or an active energy ray curable adhesive can be used. As an aqueous adhesive agent, the adhesive agent containing a polyvinyl alcohol-type resin aqueous solution, an aqueous two-component type urethane type emulsion adhesive agent, etc. are mentioned.

The so-called active energy ray curable adhesive refers to an adhesive that is cured by irradiating active energy rays such as ultraviolet rays. Examples include those containing polymerizable compounds and photopolymerization initiators, those containing photoreactive resins, and those containing adhesives. Resins and photoreactive crosslinkers, etc. Examples of polymerizable compounds include photocurable epoxy monomers, photocurable (meth)acrylic monomers, and photocurable urethane monomers, or photopolymerizable monomers derived from photopolymerization. Oligomers of sexual monomers, etc. Examples of the photopolymerization initiator include substances that generate active species such as neutral radicals, anionic radicals, and cationic radicals by irradiation with active energy rays such as ultraviolet rays. As the active energy ray curable adhesive containing a polymerizable compound and a photopolymerization initiator, those containing a photocurable epoxy-based monomer and a photocationic polymerization initiator can be preferably used.

[10] Manufacturing method of optical laminate The optical laminate can be manufactured by a method including the steps of bonding the layers constituting the optical laminate to each other through an adhesive layer or further through an adhesive layer. When the layers are bonded to each other via the adhesive layer or the adhesive layer, in order to improve the adhesion, it is preferable to perform surface activation treatment such as corona treatment on one or both surfaces of the bonding surface. The polarizing element layer or retardation layer can be formed on the thermoplastic resin film or substrate film directly or via an alignment film. The thermoplastic resin film or substrate film can be incorporated into the optical laminate, or can be formed from the polarizing element layer or retardation The layer peels off and does not become a constituent element of the optical laminate. The specific manufacturing method of the optical laminate should be understood by referring to the items in the following examples.

＜Display device＞ The display device of the present invention includes the above-mentioned optical laminate of the present invention. The display device is not particularly limited, and examples thereof include image display devices such as organic EL display devices, inorganic EL display devices, liquid crystal display devices, and electroluminescence display devices. The display device may also have a touch panel function. The optical laminate is suitable for flexible display devices that can be bent or folded. In the display device, the optical laminate is arranged on the viewing side of the display device included in the display device with the front panel facing outward (the side opposite to the display device side, that is, the viewing side).

The display device of the present invention can be used as mobile devices such as smart phones, tablets, televisions, digital photo frames, electronic billboards, measuring devices or scales, business equipment, medical equipment, computer equipment, etc. Since the display device of the present invention suppresses the distortion of the reflected image reflected on the surface of the front panel, the visibility of the screen is excellent. [Example]

Hereinafter, the present invention will be further described in detail with examples, but the present invention is not limited to these examples. In the examples, the% and parts that indicate the content or usage amount are the quality standard unless otherwise specified.

The measurement methods for the following items are as follows. [a] Layer thickness The measurement was performed using a contact-type film thickness measurement device ("MS-5C" manufactured by Nikon Co., Ltd.). However, the polarization element layer, the alignment film, and the retardation layer were measured using a laser microscope ("OLS3000" manufactured by Olympus Co., Ltd.).

[b] Storage modulus of adhesive layer For the sample of the adhesive layer accumulated in a thickness of 150 μm, use a rheometer ("MCR-301" manufactured by Anton Parr) by the torsional shear method at a temperature of 25°C and a measurement frequency of 1 Hz. Determine the storage modulus (G') [MPa].

[c] Creep value C of the adhesive layer For a cylindrical adhesive layer sample with a diameter of 8 mm (the adhesive sheet A is a sample with a thickness of 5 μm and the adhesive sheet B is a sample with a thickness of 25 μm), a rheometer (MCR-MCR- manufactured by Anton Parr) 300”), obtain the time-strain curve when a torque of 1200 μNm is applied to the sample at a temperature of 25°C, and set the strain change rate within 1200 seconds [%] as the creep value of the adhesive layer [% ].

[d] Tensile modulus of front panel The tensile elastic modulus of the front panel 10 is measured under the following conditions. Measurement environment: temperature 23℃, relative humidity 55%RH Sample size: width: 4 mm, length: 110 mm (length direction = stretching direction) Stretching speed: 4 mm/min.

<Example 1> According to the following procedure, an optical laminate having the same configuration as in FIG. 2 was produced. (1) Preparation of the front panel A polyimide film (thickness of the whole: 30 μm) with hard coating on both sides is prepared as the front panel 10. The tensile elastic modulus of the front panel is 5.7 GPa.

(2) Production of adhesive sheet A While stirring the following components in a nitrogen atmosphere, they were reacted at 55°C to obtain an acrylic resin. Butyl acrylate: 70 parts Methyl acrylate: 20 parts Acrylic: 2.0 parts Free radical polymerization initiator (2,2'-azobisisobutyronitrile): 0.2 parts Solvent (ethyl acetate): 80 parts 1.0 part of crosslinking agent ("Coronate L" manufactured by Tosoh Co., Ltd.) and 0.5 part of silane coupling agent ("X-12-981" manufactured by Shin-Etsu Silicones Co., Ltd.) were mixed with the obtained acrylic Resin, and add ethyl acetate so that the overall solid content concentration becomes 10%, thereby obtaining an adhesive composition. Using an applicator, apply the obtained adhesive composition to a release-treated polyethylene terephthalate film (release film B, thickness 38 μm) so that the thickness after drying becomes 5 μm. Type treatment surface. The coating layer was dried at 100°C for 1 minute to obtain a film with an adhesive layer. After that, another polyethylene terephthalate film (release film A, thickness 38 μm) that has undergone a release treatment is attached to the exposed surface of the adhesive layer. After that, it was cured for 7 days at a temperature of 23°C and a relative humidity of 50%RH. In this way, an adhesive sheet A including release film A/adhesive layer/release film B was produced. The storage modulus of the adhesive layer of the adhesive sheet A at 25°C is 1.00 MPa.

(3) Production of laminated body A with polarizing element layer (3-1) Preparation of polymerizable liquid crystal compound According to the method described in Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), the polymerizable liquid crystal compound represented by the following formula (1-6) (hereinafter, also referred to as " Compound (1-6)") and a polymerizable liquid crystal compound represented by the following formula (1-7) (hereinafter also referred to as "compound (1-7)").

(3-2) Preparation of dichroic pigment The azo dyes described in the examples of JP 2013-101328 A represented by the following formulas (2-1a), (2-1b) and (2-3a) were prepared as dichroic dyes.

(3-3) Preparation of composition for forming polarizing element layer 75 parts of compound (1-6) and 25 parts of compound (1-7) as polymerizable liquid crystal compounds, and formulas (2-1a), (2-1b) and (2-3a) as dichroic dyes 2.5 parts each of the indicated azo dye, 2-dimethylamino-2-benzyl-1-(4-morpholinylphenyl)butan-1-one (manufactured by BASF Japan) as a polymerization initiator 6 parts of "Irgacure369") and 1.2 parts of polyacrylate compound ("BYK-361N" manufactured by BYK-Chemie) as a leveling agent were mixed with 400 parts of toluene as a solvent, and the obtained mixture was heated at 80°C It stirred for 1 hour, thereby preparing the composition for polarizing element layer formation.

(3-4) Preparation of composition for forming alignment film The polymer having a photoreactive group containing the following structural units was dissolved in cyclopentanone so that the concentration became 5% to prepare an alignment film forming composition.

(3-5) Production of laminated body A with polarizing element layer The composition for forming the alignment film obtained in (3-4) above was coated on the triacetate cellulose (TAC) film by the bar coating method (Thickness: 25 μm), heat and dry in a drying oven at 80°C for 1 minute. Polarized UV (Ultraviolet) irradiation treatment was performed on the obtained dry coating film to form a first alignment film (AL1). Polarized UV treatment makes the light irradiated from the UV irradiation device (“SPOT CURE SP-7” manufactured by Ushio Electric Co., Ltd.) pass through the wire grid (“UIS-27132##” manufactured by Ushio Electric Co., Ltd.) at the wavelength It is performed under the condition that the cumulative light intensity measured at 365 nm is 100 mJ/cm ² . The thickness of the first alignment film (AL1) is 100 nm.

Use the bar coating method to apply the polarizing element layer forming composition obtained in (3-3) above to the formed first alignment film (AL1), and heat and dry it in a drying oven at 120°C for 1 minute. , Cool to room temperature. Using the above-mentioned UV irradiation device, the dried coating film was irradiated with ultraviolet rays at a cumulative light amount of 1200 mJ/cm ² (365 nm reference), thereby forming a polarizing element layer 30 (pol). The thickness of the obtained polarizing element layer 30 was 1.8 μm. In this way, a laminate A including the polarizing element layer 30/first alignment film (AL1)/thermoplastic resin film layer 90 (TAC film) was obtained.

(4) Production of laminated body C with first retardation layer (4-1) Preparation of the composition for forming the first retardation layer Each component shown below was mixed, and the obtained mixture was stirred at 80 degreeC for 1 hour, and the 1st phase difference layer formation composition was prepared. Compound b-1 represented by the following formula: 80 parts

下述式所示之化合物b-2：20份

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

聚合起始劑(BASF Japan公司製造之「Irgacure369」、2-二甲胺基-2-苄基-1-(4-嗎啉基苯基)丁烷-1-酮)：6份 調平劑(BYK-Chemie公司製造之「BYK-361N」、聚丙烯酸酯化合物)：0.1份 溶劑(環戊酮)：400份

Polymerization initiator ("Irgacure369" manufactured by BASF Japan, 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one): 6 parts of leveling agent ("BYK-361N" manufactured by BYK-Chemie, polyacrylate compound): 0.1 part Solvent (cyclopentanone): 400 parts

(4-2) Production of laminated body C with first retardation layer Prepare a polyethylene terephthalate (PET) film with a thickness of 100 μm as a base film, and apply the above (3) The composition for forming an alignment film obtained in -4) was coated on the film, and heated and dried in a drying oven at 80°C for 1 minute. The obtained dry coating film was subjected to polarization UV irradiation treatment to form a third alignment film (AL3). Polarized UV treatment is performed using the above-mentioned UV irradiation device, and the cumulative light quantity measured at a wavelength of 365 nm is 100 mJ/cm ² . In addition, it is performed so that the polarization direction of the polarized light UV becomes 45° with respect to the absorption axis of the polarizing element layer 30.

The first phase difference layer forming composition obtained in the above (4-1) was coated on the formed third alignment film (AL3) by the bar coating method, and heated and dried in a drying oven at 120°C 1 After minutes, cool to room temperature. Under a nitrogen atmosphere, the UV irradiation device was used to irradiate the obtained dry coating film with a cumulative light quantity of 1000 mJ/cm ² (365 nm standard) of ultraviolet rays, thereby forming the first retardation layer (first retardation layer 50) . The thickness of the obtained first retardation layer was 2.0 μm. The first retardation layer is a λ/4 plate (QWP) that displays a λ/4 retardation value in the in-plane direction. In this way, a laminate C including the first retardation layer (QWP)/third alignment film (AL3)/base film (PET) was obtained.

(5) Production of laminate B with second retardation layer (5-1) Preparation of the composition for forming the second retardation layer Each component shown below was mixed, and the obtained mixture was stirred at 80 degreeC for 1 hour, and the 2nd composition for phase difference layer formation was prepared. Compound c-1 represented by the following formula (LC242, manufactured by BASF Japan): 100 parts

聚合起始劑(BASF Japan公司製造之「Irgacure907」、2-甲基-4'-(甲硫基)-2-嗎啉基苯丙酮)：2.6份 調平劑(BYK-Chemie公司製造之「BYK-361N」、聚丙烯酸酯化合物)：0.5份 添加劑(BASF Japan公司製造之「LR9000」)：5.7份 溶劑(丙二醇1-單甲醚2-乙酸酯)：412份

Polymerization initiator ("Irgacure907" manufactured by BASF Japan, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone): 2.6 parts of leveling agent (made by BYK-Chemie BYK-361N", polyacrylate compound): 0.5 parts of additives ("LR9000" manufactured by BASF Japan): 5.7 parts of solvent (propylene glycol 1-monomethyl ether 2-acetate): 412 parts

(5-2) Production of laminate B with second retardation layer Prepare a polyethylene terephthalate (PET) film with a thickness of 38 μm as a base film, and apply the above (3) The composition for forming an alignment film obtained in -4) is coated on the film, and heated and dried in a drying oven at 90° C. for 1 minute. UV irradiation treatment was performed on the obtained dry coating film to form a second alignment film (AL2). The UV treatment is performed using the above-mentioned UV irradiation device, and the cumulative light quantity measured at a wavelength of 365 nm is 100 mJ/cm ² .

The second phase difference layer forming composition obtained in (5-1) above was coated on the second alignment film (AL2) formed by the bar coating method, and heated and dried in a drying oven at 90°C 1 minute. Under a nitrogen atmosphere, using the above-mentioned UV irradiation device, the obtained dry coating film was irradiated with ultraviolet rays with a cumulative light quantity of 1000 mJ/cm ² (365 nm reference) to form a second retardation layer (second retardation layer 70) . The thickness of the obtained second retardation layer was 2.0 μm. The second retardation layer is a positive C plate (posiC) showing retardation in the thickness direction. In this way, a laminate B including the second retardation layer (posiC)/the second alignment film (AL2)/the base film (PET) was obtained.

(6) Production of optical laminate This will be described with reference to FIGS. 3 to 7. In addition, the alignment film is omitted in FIGS. 3 to 7. In addition, in the bonding of all the layers shown below, corona treatment (output 0.3 kW, speed 3 m/min, 1 time) is applied to the bonding surfaces of each of the two bonded layers and then bonded (about The other embodiments and comparative examples are also the same).

First, peel off the release film A of the adhesive sheet A obtained in (2) above, and attach the exposed adhesive layer to the surface of the polarizing element layer 30 of the laminate A obtained in (3) above to obtain the layer shown in FIG. 3 Show the layered body. The adhesive layer of the adhesive sheet A corresponds to the second adhesive layer 40. In FIG. 3, reference numeral 41 denotes a release film B. Next, peel off the release film B from the laminate shown in FIG. 3, and bond the first retardation layer (first retardation layer 50) of the laminate C obtained in (4) above to the exposed adhesive layer. The laminate shown in Figure 4 was obtained. In FIG. 4, reference numeral 51 denotes a base film (PET).

Next, prepare a second adhesive sheet A, peel off the release film A of the adhesive sheet A, and peel the base film from the laminate shown in FIG. 4, and bond the exposed surfaces to each other to obtain the laminate shown in FIG. 5 body. The adhesive layer of the second adhesive sheet A corresponds to the third adhesive layer 60. In FIG. 5, reference numeral 41 denotes a release film B. Next, peel off the release film B from the laminate shown in FIG. 5, and paste the second retardation layer (second retardation layer 70) of the laminate B obtained in (5) above on the exposed adhesive layer surface, The laminate shown in Figure 6 is obtained. The base film (PET) of the laminate B corresponds to the supporting base 80.

Next, prepare the third adhesive sheet A, peel off the release film A of the adhesive sheet A, and bond the exposed adhesive layer to the thermoplastic resin film layer 90 (TAC film) of the laminate shown in FIG. 6 to obtain The laminate shown in Figure 7. The adhesive layer of the third adhesive sheet A corresponds to the first adhesive layer 20. In FIG. 7, reference numeral 41 denotes a release film B. Finally, the release film B is peeled off from the laminate shown in FIG. 7, and the front panel 10 is prepared in (1) above by bonding the exposed adhesive layer to the surface of the exposed adhesive layer to obtain an optical laminate having the same configuration as in FIG.

<Example 2> According to the following procedure, an optical laminate was produced. Description will be made with reference to Figs. In addition, the alignment film is omitted in FIGS. 8 to 10. First, in the same manner as in Example 1, the laminate shown in FIG. 3 was obtained. The adhesive layer contained in this laminate corresponds to the second adhesive layer 40. Next, laminate C and laminate B were produced in the same manner as in Example 1, using ultraviolet curable adhesive (epoxy ultraviolet curable adhesive manufactured by ADEKA Co., Ltd., viscosity at 25°C: 44 mPa· s) The first retardation layer side of the laminate C and the second retardation layer side of the laminate B are bonded. After that, the cumulative amount of light irradiated from the side of the layered body B (the cumulative amount of light irradiation intensity in the wavelength region of 280-320 nm) is about 250 mJ/cm ² (measured by the measuring machine: UV Power PuckII manufactured by FusionUV The measured value) of ultraviolet (UVB) to obtain the laminate shown in Figure 8. In this laminate, the base film (PET) included in the laminate B corresponds to the support base 80. In FIG. 8, reference numeral 61 represents an adhesive layer (cured layer of an ultraviolet curable adhesive), and reference numeral 51 represents a base film (PET) included in the laminate C.

Next, the release film B is peeled from the laminate shown in FIG. 3, and the base film is peeled from the laminate shown in FIG. 8, and the exposed surfaces are bonded to each other to obtain the laminate shown in FIG. 9. Next, prepare a second adhesive sheet A, peel off the release film A of the adhesive sheet A, and bond the exposed adhesive layer to the thermoplastic resin film layer 90 (TAC film) of the laminate shown in FIG. 9 to obtain The laminate shown in Figure 10. The adhesive layer of the second adhesive sheet A corresponds to the first adhesive layer 20. In FIG. 10, reference numeral 41 denotes a release film B. Finally, peel off the release film B from the laminate shown in FIG. 10, and affix the same front panel 10 (thickness of the whole: 30 μm) to the exposed adhesive layer on the surface of the exposed adhesive layer. The layer 61 has an optical laminate having the same configuration as that of FIG. 2 except that the third adhesive layer 60 is replaced.

<Example 3> An optical laminate was obtained in the same manner as in Example 2 except that a polyimide film (tensile modulus of elasticity: 5.5 GPa) having a hard coat layer on both sides with a total thickness of 50 μm was used as the front panel 10.

<Example 4> An optical laminate was obtained in the same manner as in Example 1, except that a polyimide film (tensile modulus of elasticity: 5.6 GPa) having a hard coat layer on both sides with a total thickness of 70 μm was used as the front panel 10.

<Example 5> An optical laminate was obtained in the same manner as in Example 2 except that a polyimide film (tensile modulus of elasticity: 5.6 GPa) having a hard coat layer on both sides with a total thickness of 70 μm was used as the front panel 10.

<Example 6> (1) Production of adhesive sheet B While stirring the following components in a nitrogen atmosphere, they were reacted at 55°C to obtain an acrylic resin. Butyl acrylate: 70 parts Methyl acrylate: 20 parts Acrylic: 1.0 part Free radical polymerization initiator (2,2'-azobisisobutyronitrile): 0.2 parts Solvent (ethyl acetate): 80 parts 0.3 parts of crosslinking agent ("Coronate L" manufactured by Tosoh Co., Ltd.) and 0.5 part of silane coupling agent ("X-12-981" manufactured by Shin-Etsu Silicones Co., Ltd.) were mixed in the obtained acrylic Resin, and add ethyl acetate so that the overall solid content concentration becomes 10%, thereby obtaining an adhesive composition. Using an applicator, apply the obtained adhesive composition to the release-treated polyethylene terephthalate film (release film B, thickness 38 μm) so that the thickness after drying becomes 25 μm. Type treatment surface. The coating layer was dried at 100°C for 1 minute to obtain a film with an adhesive layer. After that, another polyethylene terephthalate film (release film A, thickness 38 μm) that was released after the release treatment was attached to the exposed surface of the adhesive layer. After that, it was cured for 7 days at a temperature of 23°C and a relative humidity of 50%RH. In this way, an adhesive sheet B including release film A/adhesive layer/release film B was produced. The storage modulus of the adhesive layer of the adhesive sheet B at 25° C. is 0.05 MPa.

(2) Production of optical laminate Except for the use of a polyimide film (tensile modulus of elasticity: 5.6 GPa) with a thickness of 70 μm and a hard coating on both sides as the front panel 10, and the use of the adhesive sheet B produced in (1) above instead The adhesive sheet A was used as an adhesive sheet used in the laminate of the first adhesive layer 20 and the second adhesive layer 40, and an optical laminate was obtained in the same manner as in Example 2.

<Example 7> An optical laminate was obtained in the same manner as in Example 1, except that a polyimide film (tensile modulus of elasticity: 5.4 GPa) with a hard coat layer on both sides having a thickness of 120 μm as a whole was used as the front panel 10.

<Example 8> An optical laminate was obtained in the same manner as in Example 2 except that a polyimide film (tensile modulus of elasticity: 5.4 GPa) having a hard coat layer on both sides with a thickness of 120 μm as a whole was used as the front panel 10.

<Example 9> Except for the laminate A having a polarizing element layer 30 (thickness 8 μm) containing a stretched polyvinyl alcohol film on a cyclic polyolefin resin film (thickness 13 μm), it was used in the same manner as in Example 1 An optical laminate having the same constitution as in Fig. 2 was obtained. The cyclic polyolefin resin film corresponds to the thermoplastic resin film layer 90.

The laminated body A used in this embodiment was produced by the following procedure. A polyvinyl alcohol film with a thickness of 20 μm (average degree of polymerization of about 2,400, saponification degree of 99.9 mol% or more) is uniaxially stretched to about 4.9 times by dry stretching. Furthermore, maintaining the stretched state, the film was immersed in pure water at 60°C for 1 minute. Next, the membrane was immersed in a 28°C aqueous solution with a mass ratio of iodine/potassium iodide/water of 0.05/5/100 for 60 seconds. After that, the film was immersed in an aqueous solution at 72°C with a mass ratio of potassium iodide/boric acid/water of 8.5/8.5/100 for 300 seconds. Then, the film was washed with pure water at 26° C. for 20 seconds, and then dried at 65° C. to obtain an 8 μm-thick polarizing element (polarizing element layer 30) with iodine adsorbed and aligned on the polyvinyl alcohol film. Then, the polarizing element and the cyclic olefin resin film (thickness 13 μm) were bonded together via an aqueous adhesive to obtain a laminate A as a polarizing plate.

<Example 10> Except for the laminate A having a polarizing element layer 30 (thickness 8 μm) containing a stretched polyvinyl alcohol film on a cyclic polyolefin resin film (thickness 13 μm), it was used in the same manner as in Example 5 An optical laminate having the same configuration as that of FIG. 2 except for having an adhesive layer 61 instead of the third adhesive layer 60 was obtained. The cyclic polyolefin resin film corresponds to the thermoplastic resin film layer 90. The manufacturing procedure of the laminated body A used in this embodiment is the same as that of the embodiment 9.

<Comparative example 1> Except that the adhesive sheet B was used instead of the adhesive sheet A as the adhesive sheet used in the stack of the first adhesive layer 20, the second adhesive layer 40, and the third adhesive layer 60, the same method as in Example 1 was used. Obtain an optical laminate.

＜Comparative example 2＞ An optical laminate was obtained in the same manner as in Example 2, except that the adhesive sheet B was used instead of the adhesive sheet A as the adhesive sheet used in the laminate of the first adhesive layer 20 and the second adhesive layer 40.

<Comparative Example 3> An optical laminate was obtained in the same manner as in Comparative Example 2 except that a polyimide film (tensile modulus of elasticity: 5.5 GPa) having a hard coat layer on both sides with a total thickness of 50 μm was used as the front panel 10.

<Comparative Example 4> An optical laminate was obtained in the same manner as in Comparative Example 1, except that a polyimide film (tensile modulus of elasticity: 5.6 GPa) having a hard coat layer on both sides with a thickness of 70 μm as a whole was used as the front panel 10.

Regarding the optical laminate produced in the Examples and Comparative Examples, the thickness T of the front panel, the creep value C of each adhesive layer, and the T/C _{total are} summarized in Table 1.

(Evaluation test) [A] Evaluation of reflected images Place the optical laminate in a dark room with the front panel side up, and light up a fluorescent lamp containing two linear fluorescent tubes on the ceiling of the room. Visually observe the image of the fluorescent tube reflected on the surface of the front panel, and evaluate the degree of suppression of the distortion of the image according to the following evaluation criteria. The results are shown in Table 1. A: The fluorescent tube is completely or roughly linear. B: The fluorescent tube is slightly distorted. C: Distortion of the fluorescent tube is obvious.

[B] Evaluation of Flexibility For the optical laminate, a bending test was performed according to the following procedure. Figure 11 is a schematic diagram illustrating the method of the bendability test. A bending device ("STS-VRT-500" manufactured by Science Town Corporation) equipped with two mounting tables 501 and 502 is prepared, and the optical laminate 100 is placed on the mounting tables 501 and 502 (FIG. 11(a)). The distance (gap) C between the two mounting tables 501 and 502 is set to 2 mm (1.0R). The mounting tables 501 and 502 can swing centered on the gap C between the two mounting tables, and initially the two mounting tables 501 and 502 form the same plane. The two mounting tables 501, 502 will be rotated upwards by 90 degrees with the position P1 and the position P2 as the center of the rotation axis to close the two mounting tables 501, 502 (Figure 11(b)), and the mounting tables 501, 502 will be set again The unfolding action is defined as one bending. This operation is repeatedly performed, and the number of bending times until a crack occurs in the optical layered body 100 first is counted. The evaluation criteria are as follows. The results are shown in Table 1. AA (extremely good): more than 100,000 times A (good): more than 50,000 times but less than 100,000 times B (usable): more than 30,000 times but less than 50,000 times C (slightly worse): more than 10,000 times and less than 30,000 times D (bad): less than 10,000 times

[Table 1] Front panel thickness T Creep value C(%) T/C _total Evaluation (μm) 1st adhesive layer 2nd adhesive layer 3rd adhesive layer (μm/%) Reflected image Flexibility Example 1 30 30 30 30 0.33 A A Example 2 30 30 30 - 0.50 A A Example 3 50 30 30 - 0.83 A A Example 4 70 30 30 30 0.78 A A Example 5 70 30 30 - 1.17 A A Example 6 70 144 144 - 0.24 A A Example 7 120 30 30 30 1.33 A C Example 8 120 30 30 - 2.00 A C Example 9 30 30 30 30 0.33 A A Example 10 70 30 30 - 1.17 A A Comparative example 1 30 144 144 144 0.07 C AA Comparative example 2 30 144 144 - 0.10 B AA Comparative example 3 50 144 144 - 0.17 B AA Comparative example 4 70 144 144 144 0.16 B AA

1, 2: Optical laminate 10: Front panel 20: The first adhesive layer 30: Polarizing element layer 40: The second adhesive layer 41: peeling film B 50: The first retardation layer 51: base film 60: The third adhesive layer 61: Adhesive layer 70: Second retardation layer 80: Support substrate 90: Thermoplastic resin film layer 100: Optical laminate 501, 502: Mounting table C: distance P1, P2: location

Fig. 1 is a schematic cross-sectional view showing an example of the optical laminate of the present invention. Fig. 2 is a schematic cross-sectional view showing another example of the optical laminate of the present invention. 3 is a schematic cross-sectional view illustrating the method of manufacturing the optical laminate in Example 1. FIG. 4 is a schematic cross-sectional view illustrating the method of manufacturing the optical laminate in Example 1. FIG. 5 is a schematic cross-sectional view illustrating the method of manufacturing the optical laminate in Example 1. FIG. 6 is a schematic cross-sectional view illustrating the method of manufacturing the optical laminate in Example 1. FIG. FIG. 7 is a schematic cross-sectional view illustrating the method of manufacturing the optical laminate in Example 1. FIG. 8 is a schematic cross-sectional view illustrating the method of manufacturing the optical laminate in Example 2. 9 is a schematic cross-sectional view illustrating the method of manufacturing the optical laminate in Example 2. 10 is a schematic cross-sectional view illustrating the method of manufacturing the optical laminate in Example 2. Figure 11 (a) and (b) are schematic diagrams illustrating the method of bending test.

1: Optical laminate

10: Front panel

20: The first adhesive layer

30: Polarizing element layer

40: The second adhesive layer

50: The first retardation layer

60: The third adhesive layer

70: Second retardation layer

80: Support substrate

Claims (7)

An optical laminate comprising a front panel, an adhesive layer (A), a polarizing element layer, n layers [n represents any integer greater than 0] an adhesive layer (B), and a supporting substrate in this order, and satisfying the following Formula (1): 0.2≦T/C _total (1) [In formula (1), T represents the thickness of the front panel [μm]; C _total represents the adhesion between the front panel and the supporting substrate The total creep value C [%] of the agent layer at 25°C]. Such as the optical laminate of claim 1, which further satisfies the following formula (2): T/C _total ≦1.2 (2) [In formula (2), T and C _{total have} the same meaning as above]. The optical laminate of claim 1 or 2, wherein the above-mentioned n is any integer greater than one. The optical laminate according to any one of claims 1 to 3, which further includes at least one retardation layer disposed between the polarizing element layer and the supporting substrate. The optical laminate of claim 4, wherein the retardation layer includes a cured product of a polymerizable liquid crystal compound. The optical laminate according to any one of claims 1 to 5, wherein the polarizing element layer includes a cured product of a polymerizable liquid crystal compound. A display device comprising the optical laminate according to any one of claims 1 to 6.

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