CN114265139A - Flexible laminate - Google Patents

Abstract

The present invention provides a flexible laminate comprising a polarizer layer, a front laminate provided in contact with the front surface of the polarizer layer, and a retardation body provided on the side of the polarizer layer opposite to the front surface, wherein the total haze value of the front laminate is 5.0% or more.

Description

Flexible laminate

Technical Field

The present invention relates to a flexible laminate, and further relates to an image display device including the flexible laminate.

Background

Jp 2018 a 028573 discloses a laminate for a flexible image display device comprising an adhesive layer and an optical film, wherein the storage elastic modulus G 'at 25 ℃ of the outermost adhesive layer on the convex side when the laminate is bent is substantially the same as or smaller than the storage elastic modulus G' at 25 ℃ of the other adhesive layers.

Disclosure of Invention

In a flexible laminate comprising a front plate, a polarizer layer and a retardation body in this order, when the front plate side is repeatedly bent inward, cracks may occur in the retardation body.

The invention aims to provide a flexible laminated body, which is provided with a polarizer layer, a front laminated body arranged in contact with the front surface of the polarizer layer and a phase difference body arranged on the side opposite to the front surface of the polarizer layer, wherein even if cracks occur in the phase difference body, the cracks are not easy to be seen.

The invention provides a flexible laminate and an image display device

[1] A flexible laminate comprising a polarizer layer, a front laminate provided in contact with the front surface of the polarizer layer, and a phase difference body provided on the side of the polarizer layer opposite to the front surface,

the front laminate has a total haze value of 5.0% or more.

[2] The flexible laminate according to [1], wherein the front laminate has an internal haze value of 5.0% or more.

[3] The flexible laminate according to [1] or [2], wherein the front laminate comprises a protective layer, a 1 st adhesive layer, and a front panel in this order from the polarizer layer side.

[4] The flexible laminate according to any one of [1] to [3], wherein the phase difference body comprises a λ/4 layer.

[5] The flexible laminate according to [4], wherein the phase difference body further comprises a positive C layer or a λ/2 layer.

[6] The flexible laminate according to any one of [1] to [5], further comprising a touch sensor panel on a side of the retardation body opposite to the polarizer layer side.

[7] An image display device comprising the flexible laminate according to any one of [1] to [6 ].

According to the present invention, there can be provided a flexible laminate comprising a polarizer layer, a front laminate provided in contact with the front surface of the polarizer layer, and a retardation body provided on the side of the polarizer layer opposite to the front surface, wherein even when cracks occur in the retardation body, the cracks are not easily visible.

Drawings

Fig. 1 is a schematic cross-sectional view schematically showing an example of the flexible laminate of the present invention.

Fig. 2 is a schematic cross-sectional view schematically showing a method for producing a flexible laminate according to the present invention.

Description of the symbols

100 flexible laminate, 109 substrate film, 110, 111 front panel, 120 1 st adhesive layer, 130 linear polarizer, 131 protective layer, 132 polarizer layer, 133 overcoat, 140 retarder, 141 1 st retardation layer, 142 2 nd retardation layer, 143 interlayer laminate, 151 substrate film, 152 touch sensor panel, 160 nd adhesive layer.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments. In all the drawings below, the scale of each component shown in the drawings is appropriately adjusted to facilitate understanding of the component, and the scale is not necessarily the same as the scale of the actual component.

< Flexible laminate >

The flexible laminate of the present invention comprises a polarizer layer, a front laminate provided in contact with the front surface of the polarizer layer, and a phase difference body provided on the side of the polarizer layer opposite to the front surface.

The total haze value of the former laminate is 5.0% or more. In the flexible laminate of the present invention, the total haze value of the front laminate is 5.0% or more, and thus, even when cracks occur in the retardation body, the cracks are not easily recognized.

An embodiment of the flexible laminate according to the present invention will be described with reference to fig. 1. The flexible laminate 100 shown in fig. 1 includes a front panel 110, a 1 st adhesive layer 120, a linear polarizing plate 130, a 2 nd adhesive layer 160, and a phase difference body 140 in this order. The flexible laminate 100 has a 1 st adhesive layer 120 interposed between the front panel 110 and the linear polarizing plate 130 for bonding them together, and has a 2 nd adhesive layer 160 interposed between the linear polarizing plate 130 and the phase difference body 140 for bonding them together. The flexible laminate 100 may further include a touch sensor panel on the opposite side of the phase difference body 140 from the 2 nd pressure-sensitive adhesive layer 160, and in this case, it is preferable to include a 3 rd pressure-sensitive adhesive layer 150 interposed between the phase difference body 140 and the touch sensor panel to bond them. Note that, even if the touch sensor panel is not provided, the 3 rd pressure-sensitive adhesive layer may be interposed between the phase difference body 140 and another optical member and bonded thereto.

The linearly polarizing plate 130 includes a protective layer 131 and a polarizer layer 132 in this order from the front panel 110 side. The retardation body 140 includes a 1 st retardation layer 141 and a 2 nd retardation layer 142 in this order from the front panel 110 side. The 1 st retardation layer 141 and the 2 nd retardation layer 142 may be laminated via an interlayer lamination layer 143.

In the flexible laminate, all layers located on the front surface side of the polarizer layer constitute the front laminate. In the flexible laminate 100 shown in fig. 1, the laminate including the layers "protective layer 131/1 st adhesive layer 120/front panel 110" corresponds to a front laminate provided in contact with the front surface of the polarizer layer. The flexible laminate 100 shown in fig. 1 is only one embodiment of the flexible laminate of the present invention, and the flexible laminate of the present invention is not limited to include all the elements included in the flexible laminate 100, and may include other elements not included in the flexible laminate 100.

The flexible laminate may be used by bending the front laminate side inward (hereinafter, also referred to as inward folding), or by bending the front laminate side outward (hereinafter, also referred to as outward folding). The flexible laminate is at least capable of being bent by being folded inwardly or outwardly. In the present specification, the term "bendable" means that the laminated body can be bent without causing cracks in the retardation body when the laminated body is repeatedly bent 10 ten thousand times under a condition of a bending radius of 3 mm. The bending includes a bent form in which a curved surface is formed at a bent portion. In the form of the bend, the radius of curvature of the inner surface of the bend is not particularly limited. The bending includes a form in which the inner surface is bent at a bending angle of more than 0 ° and less than 180 °, and a form in which the inner surface is folded at a bending radius of approximately zero or a bending angle of 0 °. The flexible laminate is suitable for a flexible display because it can be bent.

Even in a flexible laminate, if the laminate is repeatedly bent or held in a bent state for a long period of time, cracks may occur in the bent portion of the phase difference body. In particular, if the retardation film is repeatedly bent to be folded inward or is kept in a state of being bent to be folded inward for a long time, cracks are likely to occur in the bent portion of the retardation body. The flexible laminate of the present invention has an effect that even when cracks occur in the retardation body, the cracks are not easily visible.

The flexible laminate may have, for example, a square shape in plan view, preferably a square shape having long sides and short sides, and more preferably a rectangular shape. The layers constituting the flexible laminate may be subjected to corner rounding, end notching, or perforation

The flexible laminate can be used for, for example, an image display device. The image display device is not particularly limited, and examples thereof include an organic electroluminescence (organic EL) display device, an inorganic electroluminescence (inorganic EL) display device, a liquid crystal display device, and an electroluminescence display device.

[ haze value of front laminate ]

In the flexible laminate, the total haze value of the front laminate is 5.0% or more. The total haze value is the sum of the internal haze value and the surface haze value. When the total haze value of the front laminate is 5.0% or more, even when cracks occur in the retardation body of the flexible laminate, the cracks are not easily recognized. It is considered that the above-mentioned effects can be obtained by scattering light transmitted through the polarizer layer when the total haze value on the viewing side of the polarizer layer is in the above-mentioned range. On the other hand, even if light is scattered between the polarizer layer and the phase difference body, a part of the scattered light is absorbed by the polarizer layer. Therefore, it is considered that the internal haze of the layer located between the polarizer layer and the retardation body does not easily contribute to the above-described effects. The total haze value of the front laminate is preferably 8.0% or more, more preferably 10.0% or more, and may be 15.0% or more. The total haze value of the former laminate is preferably 60.0% or less, more preferably 50.0% or less. When the total haze value of the front laminate is 60.0% or less, an image can be displayed with high sharpness.

In the flexible laminate, the internal haze value of the front laminate is preferably 5.0% or more, more preferably 8.0% or more, further preferably 10.0% or more, and may be 15.0% or more. The internal haze value of the front laminate is preferably 60.0% or less. This is because the front laminate can be configured to have a total haze value of 5.0% or more even if the surface haze value is small, since the internal haze value is 5.0% or more. In the former laminate, the surface haze value is preferably 1.0% or less, more preferably 0.5% or less. When the surface haze value of the front surface laminate is 1.0% or less, a flexible laminate having a glossy front surface can be formed.

The total haze value of the front laminate can be adjusted by adjusting the internal haze values of the respective layers constituting the front laminate. In the flexible laminate 100 shown in fig. 1, for example, the total haze value of the front laminate can be adjusted by adjusting the internal haze value of the 1 st adhesive layer 120.

The method of measuring the internal haze value of the front laminate may be a method of measuring the internal haze value of the entire front laminate, or may be a method of calculating the internal haze value of the front laminate by a method of measuring the internal haze values of the respective layers constituting the front laminate and summing up the internal haze values of the respective layers, as shown in examples described later. In the above-described measurement method, it may not be necessary to measure again a layer having a significant internal haze value among the layers constituting the front laminate. The surface haze value of the front laminate is equal to the surface haze value of the front side of the foremost layer of the front laminate. When the internal haze value of the front laminate is 5.0% or more, the characteristic that the total haze value is 5.0% or more is satisfied. This is because the total haze value does not become a value smaller than that of the internal haze value.

[ Total haze value, internal haze and Transmission clarity of Flexible laminate ]

The flexible laminate preferably has a total haze value of 60.0% or less. The internal haze value of the flexible laminate is preferably 60.0% or less. When the total haze value and the internal haze of the flexible laminate are 60.0% or less, an image can be displayed with high sharpness. The flexible laminate may have a total haze value of 5.0% or more. The transmission clarity of the flexible laminate is preferably 300% or more, and more preferably 330% or more, as measured by the measurement method described in the examples below. The flexible laminate has a transmission clarity of 400% or less.

[ front panel ]

The front panel 110 is not limited in material and thickness as long as it is a plate-like body capable of transmitting light, and may have a single-layer structure or a multi-layer structure, and examples thereof include a plate-like body made of glass (e.g., a glass plate, a glass film, etc.), a plate-like body made of resin (e.g., a resin plate, a resin sheet, a resin film, etc.), and a laminate of a plate-like body made of glass and a plate-like body made of resin. The front panel may be a layer constituting the outermost surface of the image display device on the viewing side.

As the glass plate or the glass film, a strengthened glass for display is preferably used. The thickness of the glass plate or the glass film is, for example, 10 μm to 1000. mu.m. By using a glass plate or a glass film, an optical member having excellent mechanical strength and surface hardness can be constituted.

The resin film is not particularly limited as long as it is a resin film that can transmit light. Examples of the film include films formed of polymers such as triacetylcellulose, acetylcellulose butyrate, ethylene-vinyl acetate copolymer, propionylcellulose, butyrylcellulose, acetylpropionylcellulose, polyester, polystyrene, polyamide, polyetherimide, poly (meth) acrylic acid, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyetherketone, polyether etherketone, polyethersulfone, poly (meth) methyl acrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyamideimide. These polymers may be used alone or in combination of 2 or more. When the laminate is used for a flexible display, a resin film made of a polymer such as polyimide, polyamide, or polyamideimide, which can be configured to have excellent flexibility, high strength, and high transparency, is preferably used. In the present specification, "(meth) acrylic" means either acrylic or methacrylic. The same applies to (meth) acrylates and the like.

When the front panel is a resin film, the resin film may be one in which a hard coat layer is provided on at least one surface of the base film to further increase the hardness. The hard coat layer may be formed on one surface of the substrate film or on both surfaces. When the image display device described later is a touch panel type image display device, a resin film having a hard coat layer is preferably used because the surface of the front panel is a touch surface. By providing the hard coat layer, a resin film having improved hardness and scratch resistance can be produced. The hard coat layer is a cured layer of, for example, an ultraviolet curable resin. Examples of the ultraviolet curable resin include (meth) acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins. The hard coating may also contain additives in order to increase hardness. The additive is not limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof. The thickness of the resin film is, for example, 10 to 100. mu.m, preferably 20 to 60 μm.

The front panel has not only a function of protecting the front face of the image display device but also a function as a touch sensor, a blue light cut-off function, a viewing angle adjustment function, and the like.

The front panel may have an internal haze value of 0.00% or more, or 0.05% or more, or 60.0% or less, or 5.0% or less, or 1.0% or less.

[1 st adhesive layer ]

The 1 st adhesive layer 120 may be a layer interposed between the front panel 110 and the linear polarizer 130 to bond them. The "adhesive" in this specification is a substance which is in a liquid state after a curing reaction and can be bonded by applying a slight pressure at normal temperature in a short time, and is also referred to as a pressure-sensitive adhesive, for example. On the other hand, the term "adhesive" as used herein refers to an adhesive other than an adhesive (pressure-sensitive adhesive), and is a material which is solid after a curing reaction and has an elastic modulus of 100MPa or more after curing. The 1 st adhesive layer 120 may be 1 layer or may be a layer composed of 2 or more layers, but is preferably 1 layer.

The internal haze value of the 1 st pressure-sensitive adhesive layer 120 is preferably 0.2% or more, more preferably 1.0% or more, further preferably 5.0% or more, and particularly preferably 8.0% or more. By setting the internal haze value of the 1 st adhesive layer 120 to 0.2% or more, a front laminate having a total haze value of 5.0% or more can be easily produced. The internal haze value of the 1 st adhesive layer 120 is preferably 60.0% or less, and more preferably 50.0% or less. The 1 st pressure-sensitive adhesive layer 120 can be configured to have excellent adhesiveness when the internal haze value is 60.0% or less.

The internal haze value of the 1 st pressure-sensitive adhesive layer 120 can be adjusted by, for example, the type, content, and the like of a light diffusing agent added to impart light diffusibility to a pressure-sensitive adhesive composition described later. As the light diffusing agent, a substance having a refractive index different from that of the base polymer, such as light-transmitting fine particles or glass fibers, is used. The shape of the light-transmissive fine particles may be, for example, a regular spherical shape, a flat shape, or an irregular shape. As the light-transmitting fine particles, fine particles made of an inorganic compound or fine particles made of an organic compound (polymer) can be used. The internal haze value of the 1 st binder layer 120 can be adjusted by, for example, the particle diameter of the light-transmitting fine particles used as the light diffusing agent, the ratio of the thickness of the 1 st binder layer 120 to the particle diameter of the light-transmitting fine particles, the refractive index difference between the base polymer and the light-transmitting fine particles, the blending amount of the light-transmitting fine particles, and the like.

When the amount of the light-transmitting fine particles added is large, the internal haze value tends to be large, and when the amount is small, the internal haze value tends to be small. If the refractive index difference between the base polymer and the light-transmissive fine particles is large, the internal haze value tends to be large, and if it is small, the internal haze value tends to be small.

The refractive index difference can be set to a desired value by adjusting the refractive index of the light-transmissive fine particles by the selection of the material of the light-transmissive fine particles or adjusting the refractive index of the base polymer by the material and crystallinity of the base polymer. The refractive index difference between the base polymer and the light-transmitting fine particles is, for example, 0.01 or more, and preferably 0.01 to 0.5 in consideration of brightness and visibility when the resultant image display device is produced. Since the refractive index of the base polymer is usually about 1.4, the following fine particles are preferable as the fine particles composed of an inorganic compound or an organic compound used as the light-transmitting fine particles.

Examples of the light-transmitting fine particles made of an inorganic compound include alumina (refractive index 1.76), silica (refractive index 1.45), and the like.

Examples of the light-transmitting fine particles composed of an organic compound include melamine beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate/styrene copolymer resin beads (refractive index 1.50 to 1.59), polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), epoxy resin beads (refractive index 1.5 to 1.6), silicone resin beads (refractive index 1.46), and the like.

Further, when an acrylic copolymer is selected as the base polymer, the epoxy resin beads, polymethyl methacrylate beads, and silicone resin beads are excellent in dispersibility with respect to the acrylic copolymer, and uniform and good light diffusibility is obtained, and therefore, they are suitable as light-transmitting fine particles as a light diffusing agent. The light diffusing agent is preferably spherical and monodisperse, and has uniform light diffusion.

The average particle diameter of the light-transmitting fine particles is preferably in the range of 0.1 to 20 μm. If the average particle diameter is less than 0.1. mu.m, the content may be increased in order to increase the internal haze value. On the other hand, if the average particle diameter exceeds 20 μm, the contrast of the image is adversely affected, and flicker is generated if the average particle diameter is larger than the image pitch of the display. In the above aspect, the average particle diameter of the light-transmissive fine particles is preferably in the range of 0.5 to 10 μm, and particularly preferably in the range of 1 to 6 μm. Here, the average particle diameter of the light-transmitting fine particles is, for example, a value measured by an ultracentrifugal automatic particle size distribution measuring apparatus.

The blending amount of the light-transmitting fine particles may be appropriately determined in consideration of a target internal haze value, luminance of an image display device using the same, and the like, and is preferably in the range of 1 to 40 parts by mass, and more preferably in the range of 3 to 30 parts by mass, relative to 100 parts by mass of the base polymer of the binder composition. If the content of the light-transmissive fine particles exceeds 40 parts by mass, the resolution of the screen of the image display device is reduced, and blurring may occur.

The thickness of the 1 st adhesive layer 120 is preferably 4 μm or more, more preferably 5 μm or more, and further preferably 10 μm or more. From the viewpoint of improving the bendability, the thickness of the 1 st pressure-sensitive adhesive layer 120 is preferably 100 μm or less, and more preferably 50 μm or less. The thickness of the 1 st adhesive layer 120 is the maximum thickness of the 1 st adhesive layer 120.

The 1 st pressure-sensitive adhesive layer 120 may be formed of a pressure-sensitive adhesive composition containing a resin as a base polymer, such as a (meth) acrylic resin, a rubber resin, a urethane resin, an ester resin, a silicone resin, or a polyvinyl ether resin. Among these, an adhesive composition containing a (meth) acrylic resin as a base polymer, which is excellent in transparency, durability, heat resistance, and the like, is preferable. The adhesive composition may be an active energy ray-curable type or a thermosetting type.

As the (meth) acrylic resin (base polymer) used in the adhesive composition, for example, a polymer or copolymer in which 1 or 2 or more kinds of (meth) acrylic esters such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate are used as monomers is preferably used. The base polymer preferably copolymerizes polar monomers. Examples of the polar monomer include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N-dimethylaminoethyl (meth) acrylate, and glycidyl (meth) acrylate.

The adhesive composition may contain a crosslinking agent together with the base polymer. Examples of the crosslinking agent include metal ions having a valence of 2 or more and a metal salt of carboxylic acid with a carboxyl group; is a polyamine compound and forms an amide bond with a carboxyl group; is a polyepoxy compound, a polyol and forms an ester bond with a carboxyl; is a polyisocyanate compound and forms an amide bond with a group, etc. Among them, polyisocyanate compounds are preferable.

The active energy ray-curable pressure-sensitive adhesive composition is a pressure-sensitive adhesive composition having a property of being cured by being irradiated with an active energy ray such as an ultraviolet ray or an electron beam, having an adhesive property even before irradiation with the active energy ray, and being capable of being adhered to an adherend such as a film and being cured by irradiation with the active energy ray, thereby adjusting the property such as the adhesive force. The active energy ray-curable adhesive composition is preferably an ultraviolet-curable adhesive composition. The active energy ray-curable adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the crosslinking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer and the like may be contained.

The adhesive composition may contain additives such as a light diffusing agent, a resin other than the base polymer, an adhesion imparting agent, a filler (metal powder, other inorganic powder, etc.), an antioxidant, an ultraviolet absorber, a dye, a pigment, a colorant, an antifoaming agent, an anticorrosive agent, a photopolymerization initiator, and the like.

The 1 st adhesive layer can be formed by applying a diluted solution of the above adhesive composition in an organic solvent to a substrate and drying it. When an active energy ray-curable adhesive composition is used, a cured product having a desired degree of curing can be obtained by irradiating the 1 st adhesive layer formed with an active energy ray.

[ Linear polarizing plate ]

The linear polarizer 130 may be laminated with a protective layer 131 on one side of the polarizer layer 132. The linear polarizer may be further laminated with another protective layer on the other side of the polarizer layer 132. The linearly polarizing plate 130 has a property of transmitting linearly polarized light having a vibration plane perpendicular to the absorption axis when unpolarized light is incident. The linear polarizer 130 may include a polyvinyl alcohol (hereinafter, also simply referred to as "PVA") resin film as the polarizer layer 132, or may be a cured film obtained by aligning a composition containing a dichroic dye and a polymerizable compound and polymerizing the polymerizable liquid crystal compound. The polarizer layer obtained by applying and curing a composition containing a dichroic dye and a polymerizable compound is preferable because the bending direction is not limited as compared with the polarizer layer containing a PVA-based resin film obtained by a stretching step.

The linearly polarizing plate 130 may include only the polarizer layer 132 and the protective layer 131, may further include at least one of a substrate, a resin film, and an alignment film in addition to the polarizer layer 132 and the protective layer 131, or may further include a protective layer on the surface of the polarizer layer 132 opposite to the protective layer 131. The thickness of the linear polarizer 130 is, for example, 2 μm to 100 μm, preferably 5 μm to 60 μm.

[ polarizer layer ]

A polarizer layer obtained by uniaxially stretching a PVA-based resin film dyed with iodine can be used.

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

The saponification degree of the polyvinyl alcohol resin is usually about 85 mol% to 100 mol%, and preferably 98 mol% or more. The polyvinyl alcohol resin may be modified, and for example, formaldehyde or polyvinyl acetal obtained from polyvinyl alcohol modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol resin is usually 1000 to 10000, preferably about 1500 to 5000. The average polymerization degree of the polyvinyl alcohol resin can be determined in accordance with JIS K6726 (1994). When the average polymerization degree is less than 1000, it is difficult to obtain preferable polarizing performance, and when it exceeds 10000, film processability may be deteriorated.

As another method for producing a linear polarizing plate comprising a PVA-based resin film, there is a production method comprising the steps of: first, a base film is prepared, a solution of a resin such as a polyvinyl alcohol resin is applied to the base film, and the base film is dried to remove the solvent to form a resin layer thereon. The primer layer may be formed in advance on the surface of the base film on which the resin layer is formed. As the base film, a resin film such as PET or a film using a resin that can be used for a protective layer described later can be used. Examples of the material of the primer layer include a resin obtained by crosslinking a hydrophilic resin used for a linear polarizing plate.

Next, if necessary, the amount of solvent such as water in the resin layer is adjusted, and then the base film and the resin layer are uniaxially stretched, and then the resin layer is dyed with a dichroic dye such as iodine to adsorb and orient the dichroic dye to the resin layer. Next, the resin layer adsorbed and aligned with the dichroic dye is treated with an aqueous boric acid solution as necessary, and a washing step of washing off the aqueous boric acid solution is performed. Thus, a resin layer having a dichroic dye adsorbed and oriented, that is, a polarizer layer is produced. The respective steps may be performed by known methods.

The uniaxial stretching of the base film and the resin layer may be performed before dyeing, during boric acid treatment after dyeing, or in each of these multiple stages. The base film and the resin layer may be uniaxially stretched in the MD direction (film transport direction), and in this case, the base film and the resin layer may be uniaxially stretched by a heat roll while being uniaxially stretched between rolls having different peripheral speeds. In addition, the substrate film and the resin layer may be uniaxially stretched in the TD direction (direction perpendicular to the film transport direction), and in this case, a so-called tenter method may be used. The stretching of the base film and the resin layer may be dry stretching in which the stretching is performed in the air, or wet stretching in which the stretching is performed in a state in which the resin layer is swollen with a solvent. In order to exhibit the performance of the polarizer layer, the stretching magnification is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times or more. The upper limit of the stretching ratio is not particularly limited, but is preferably 8 times or less from the viewpoint of suppressing breakage or the like.

The thickness of the polarizer layer containing the PVA-based resin film is, for example, 2 to 40 μm. The thickness of the polarizer layer may be 5 μm or more, 20 μm or less, 15 μm or less, or 10 μm or less.

A polarizer layer that is a cured film obtained by aligning a composition containing a dichroic dye and a polymerizable compound and polymerizing the polymerizable liquid crystal compound can be used. Examples of the method for producing such a polarizer layer include a method in which a composition for forming a polarizer layer containing a polymerizable liquid crystal compound and a dichroic dye is applied to a base film via an alignment film to form a polarizer layer; or a method in which a composition for forming a polarizer layer containing a polymerizable liquid crystal compound and a dichroic dye is applied to a base film on which a protective layer is formed or a base film used as a protective layer through an alignment film, and the polymerizable liquid crystal compound is polymerized and cured while maintaining a liquid crystal state to form a polarizer layer. The polarizer layer thus obtained is in a state of being laminated on a protective layer, and can be used as a polarizer layer with a protective layer. As the base film, a resin film such as a polyethylene terephthalate film can be used.

An overcoat layer may be provided on the surface of the polarizer layer 132. The overcoat layer may be formed using an overcoat layer-forming composition. Examples of the composition for forming the overcoat layer include photocurable resins and water-soluble polymers. Examples of the photocurable resin include a (meth) acrylic resin, a urethane resin, a (meth) acrylic urethane resin, an epoxy resin, and a silicone resin. Examples of the water-soluble polymer include poly (meth) acrylamide polymers; polyvinyl alcohol, and vinyl alcohol polymers such as ethylene-vinyl alcohol copolymers, ethylene-vinyl acetate copolymers, (meth) acrylic acid or anhydride thereof-vinyl alcohol copolymers; a carboxyvinyl polymer; polyvinylpyrrolidone; starches; sodium alginate; polyethylene oxide polymers, and the like. The thickness of the overcoat layer is preferably 20 μm or less, more preferably 15 μm or less, further preferably 10 μm or less, and may be 5 μm or less, and may be 0.05 μm or more and 0.5 μm or more.

As the dichroic dye, a dye having a property that the absorbance in the major axis direction of the molecule is different from the absorbance in the minor axis direction of the molecule can be used, and for example, a dye having an absorption maximum wavelength (λ max) in the range of 300 to 700nm is preferable. Examples of such dichroic dyes include acridine dyes,

Oxazine pigment, cyanine pigment, naphthalene pigment, azo pigment, anthraquinonePigments and the like, among which azo pigments are preferred. Examples of the azo dye include monoazo dye, disazo dye, trisazo dye, tetraazo dye, and stilbene azo dye, and disazo dye and trisazo dye are more preferable.

The composition for forming a polarizer layer may contain a solvent, a polymerization initiator such as a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, and the like. Known substances such as a polymerizable liquid crystal compound, a dichroic dye, a solvent, a polymerization initiator, a photosensitizer, and a polymerization inhibitor contained in the composition for forming a polarizing layer can be used, and for example, those exemplified in japanese patent application laid-open nos. 2017-102479 and 2017-83843 can be used. As the polymerizable liquid crystal compound, those exemplified as polymerizable liquid crystal compounds for obtaining a cured layer as a retardation layer described later can be used. The method for forming a linear polarizing plate using the composition for forming a polarizer layer can also employ the method exemplified in the above publication.

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

The polarizer layer produced by the above method can be used as a linear polarizing plate by peeling off the substrate film or together with the substrate film. According to the above method, the substrate film can be peeled, and thus further thinning of the linear polarizing plate can be realized.

[ protective layer ]

The protective layer 131 has a function of protecting the surface of the polarizer layer 132. In the flexible laminate, the linear polarizer 130 is disposed so that the protective layer 131 is closer to the front panel 110 than the polarizer layer 132.

The protective layer 131 may be an organic layer or an inorganic layer. The protective layer 131 may be a substrate film used in the manufacturing process of the polarizer layer 132. The organic layer can be formed using a composition for forming a protective layer, for example, a (meth) acrylic resin composition, an epoxy resin composition, a polyimide resin composition, or the like. The composition for forming a protective layer may be an active energy ray-curable composition or a thermosetting composition. The inorganic layer may be formed of, for example, silicon oxide or the like. When the protective layer 131 is an organic layer, the protective layer may be a layer called a hard coat layer.

When the protective layer 131 is an organic layer, for example, an active energy ray-curable composition for forming a protective layer is applied to a base film and cured by irradiation with active rays to form a protective layer. The substrate film can be used as described above. The substrate film is usually peeled off and removed. Examples of the method of applying the composition for forming a protective layer include spin coating. When the protective layer 131 is an inorganic layer, the protective layer can be formed by, for example, a sputtering method, an evaporation method, or the like. When the protective layer 131 is an organic layer or an inorganic layer, the thickness of the protective layer 131 may be, for example, 0.1 to 10 μm, and preferably 0.5 to 5 μm.

As the protective layer 131, for example, a resin film excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, stretchability, and the like can be used. The resin film may be a thermoplastic resin film. Specific examples of such resins include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether sulfone resin; polysulfone resin; a polycarbonate resin; polyamide resins such as nylon and aromatic polyamide; a polyimide resin; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; cyclic polyolefin resins having a cyclic norbornene structure (also referred to as norbornene-based resins); (meth) acrylic resins; a polyarylate resin; a polystyrene resin; polyvinyl alcohol resins, and mixtures thereof. When protective layers are laminated on both surfaces of the polarizer layer, the two protective layers may be of the same kind or of different kinds. The thickness of the resin film is, for example, 3 to 50 μm, preferably 5 to 30 μm.

The total haze value of the front laminate can be adjusted by the internal haze of the protective layer. In this case, the internal haze value of the protective layer is preferably 5.0% or more, more preferably 8.0% or more, and further preferably 10.0% or more. By setting the internal haze value of the protective layer to 5.0% or more, a front laminate having a total haze value of 5.0% or more can be easily produced. The internal haze value of the protective layer is preferably 60.0% or less.

[ phase difference body ]

The flexible laminate 100 can function as a circular polarizing plate by including the linear polarizing plate 130 (hereinafter, also referred to as a linear polarizing layer) and the phase difference body 140. Hereinafter, the configuration including the linear polarizer 130 and the phase difference body 140 may be referred to as a circular polarizer.

The retardation body 140 preferably includes a 1 st retardation layer 141 and a 2 nd retardation layer 142. The 1 st retardation layer 141 and the 2 nd retardation layer 142 are preferably bonded by an interlayer bonding layer 143 to be described later. The 1 st retardation layer 141 and the 2 nd retardation layer 142 may have an overcoat layer for protecting the surfaces thereof, a substrate film for supporting the 1 st retardation layer 141 and the 2 nd retardation layer 142, and the like. Examples of the 1 st retardation layer 141 and the 2 nd retardation layer 142 include a retardation layer (λ/4 layer) giving a retardation of λ/4, a retardation layer (λ/2 layer) giving a retardation of λ/2, and a positive C layer.

The phase difference body 140 preferably includes a λ/4 layer, and more preferably includes at least one of a λ/4 layer and a λ/2 layer or a positive C layer.

The retardation body 140 is formed by laminating a 1 st retardation layer 141 and a 2 nd retardation layer 142 in this order from the polarizer layer 132 side. When the retardation body includes λ/2 layers, the 1 st retardation layer 141 is a λ/2 layer, and the 2 nd retardation layer 142 is a λ/4 layer. When the retardation body 140 includes a positive C layer, the 1 st retardation layer 141 is a positive C layer and the 2 nd retardation layer 142 is a λ/4 layer, or the 1 st retardation layer 141 is a λ/4 layer and the 2 nd retardation layer 142 is a positive C layer. The thickness of the phase difference body 140 is, for example, 0.1 to 50 μm, preferably 0.5 to 30 μm, and more preferably 1 to 10 μm. Since the thin retardation member has low strength, the flexible laminate having the thin retardation member can easily enjoy the effects of the present invention.

The 1 st retardation layer 141 and the 2 nd retardation layer 142 may be formed of a resin film exemplified as a material of the above resin film, or may be formed of a layer obtained by curing a polymerizable liquid crystal compound. The 1 st retardation layer 141 and the 2 nd retardation layer 142 may further include an alignment film and a substrate film. The 1 st retardation layer 141 having an alignment film and the 2 nd retardation layer 142 having an alignment film may be treated as one unit member.

When the 1 st retardation layer 141 and the 2 nd retardation layer 142 are formed from a layer obtained by curing a polymerizable liquid crystal compound, the layer can be formed by applying a composition containing a polymerizable liquid crystal compound to a base film and curing the composition. An alignment film may be formed between the substrate film and the coating layer. The material and thickness of the base film may be the same as those of the resin film described above. When the 1 st retardation layer 141 and the 2 nd retardation layer 142 are formed by curing a polymerizable liquid crystal compound, they may be assembled in a laminate in a form having an alignment film and a base film.

The polarizing plate in which the polarizer layer 132 and the retardation body 140 are arranged so that the absorption axis of the polarizer layer 132 and the slow axis of the retardation body 140 form a predetermined angle has an antireflection function, and functions as a circular polarizing plate. When the phase difference body 140 includes the λ/4 layer, the angle formed by the absorption axis of the polarizer layer 132 and the slow axis of the λ/4 layer may be 45 ° ± 10 °. The 1 st retardation layer 141 and the 2 nd retardation layer 142 may have positive wavelength dispersibility or may have reverse wavelength dispersibility. The lambda/4 layer preferably has reverse wavelength dispersion. The polarizer layer 132 and the phase difference body 140 may be bonded to each other with an adhesive or a bonding agent.

[ interlayer lamination layer ]

The interlayer bonding layer 143 is disposed between the 1 st retardation layer 141 and the 2 nd retardation layer 142, and has a function of bonding the 1 st retardation layer 141 and the 2 nd retardation layer 142. The interlayer adhesive layer 143 may be made of an adhesive or bonding agent. The interlayer adhesive layer 143 is preferably an adhesive layer.

The thickness of the interlayer bonding layer 143 is not particularly limited, and when an adhesive layer is used as the interlayer bonding layer 143, it is preferably 1 μm or more, and may be 5 μm or more, and usually 50 μm or less, and may be 25 μm or less. When an adhesive layer is used as the interlayer adhesive layer 143, the thickness of the interlayer adhesive layer 143 is preferably 0.1 μm or more, and may be 0.5 μm or more, preferably 10 μm or less, and may be 5 μm or less.

When the adhesive composition is used to form the interlayer lamination layer 143, the above description of the adhesive composition used to form the 1 st adhesive layer can be applied, in addition to the internal haze value and the items related to the adjustment of the internal haze value. The interlayer adhesive layer 143 preferably has an internal haze value of 30% or less. If the internal haze value of the interlayer lamination layer 143 exceeds 30%, the resolution of the screen of the image display device is reduced, and a blur may occur.

The adhesive may be formed of 1 kind or a combination of 2 or more kinds of water-based adhesives, active energy ray-curable adhesives, and the like. Examples of the aqueous adhesive include a polyvinyl alcohol resin aqueous solution and an aqueous two-pack type urethane emulsion adhesive. The active energy ray-curable adhesive is an adhesive that can be cured by irradiation with an active energy ray such as ultraviolet ray, and examples thereof include an adhesive containing a polymerizable compound and a photopolymerization initiator, an adhesive containing a photoreactive resin, and an adhesive containing a binder resin and a photoreactive crosslinking agent. Examples of the polymerizable compound include photopolymerizable monomers such as a photocurable epoxy monomer, a photocurable acrylic monomer, and a photocurable urethane monomer, and oligomers derived from these monomers. Examples of the photopolymerization initiator include compounds containing active species that generate neutral radicals, anionic radicals, cationic radicals, and the like by irradiation with active energy rays such as ultraviolet rays.

[ touch sensor Panel ]

The touch sensor panel is not limited to a detection method as long as it is a sensor capable of detecting a touched position, and examples thereof include touch sensor panels of a resistive film method, a capacitive coupling method, an optical sensor method, an ultrasonic wave method, an electromagnetic induction coupling method, a surface acoustic wave method, and the like. From the viewpoint of low cost, a touch sensor panel of a resistive film type or a capacitive coupling type is preferably used. The touch sensor panel may be disposed on the side of the laminate opposite the viewing side.

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

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

[2 nd adhesive layer and 3 rd adhesive layer ]

The 2 nd adhesive layer 160 is interposed between the linear polarizer 130 and the retardation body 140 and is bonded to each other. The 3 rd adhesive layer 150 is, for example, a layer interposed between the retardation body 140 and the touch sensor panel and bonded thereto. The above description of the adhesive composition used for forming the 1 st adhesive layer can be applied to the 2 nd adhesive layer 160 and the 3 rd adhesive layer 150, except for the internal haze value and the items related to the adjustment of the internal haze value. The internal haze values of the 2 nd adhesive layer 160 and the 3 rd adhesive layer 150 are preferably 30% or less, respectively. If the internal haze value is 30% or less, the resolution of the screen of the image display device is not easily reduced, and thus the occurrence of blur (i.e., blurriness) is easily avoided.

[ adhesive layer ]

The flexible laminate 100 further includes a bonding layer for bonding the layers in the front panel 110, the linear polarizer 130, or the phase difference body 140. The attachment layer may be formed of an adhesive or bonding agent. The adhesive and the pressure-sensitive adhesive can be those exemplified above for the interlayer lamination layer.

[ image display element ]

Examples of the image display element include a liquid crystal cell, an organic electroluminescence (organic EL) display element, an inorganic electroluminescence (inorganic EL) display element, a plasma display element, and a field emission type display element.

[ method for producing Flexible laminate ]

The method for producing the flexible laminate may include the following steps (a) to (g), for example. A method for manufacturing a laminate will be described with reference to fig. 2.

(a) Step of forming protective layer 131 on base film 109

(b) Process for Forming polarizer layer 132 on protective layer 131

(c) Process for providing an overcoat layer 133 on polarizer layer 132

(d) Preparing a phase difference body 140 comprising a 1 st phase difference layer 141, an interlayer lamination layer 143, and a 2 nd phase difference layer 142, and a touch sensor panel 152 having a base film 151

(e) A step of bonding a laminate of the retardation body 140/the 3 rd pressure-sensitive adhesive layer 170/the touch sensor panel 152/the base film 151 on the overcoat layer 133 via the 2 nd pressure-sensitive adhesive layer 160 with the retardation body 140 side as a bonding surface

(f) A step of peeling off the base film 109 in contact with the protective layer 131

(g) A step of bonding the front panel 111 to the protective layer 131 via the 1 st adhesive layer 120, and then peeling off the base film 151 in contact with the touch sensor panel 152

The method for manufacturing a flexible laminate may include a step of forming an alignment film on the protective layer 131 between the steps (a) and (b). The bonding can be performed using a known laminator, a roller, a device bonder, or the like. The bonding surface may be subjected to surface treatment such as corona treatment or plasma treatment.

< image display device >

An image display device of the present invention includes the above flexible laminate. The image display device is not particularly limited, and examples thereof include an organic EL display device, an inorganic EL display device, a liquid crystal display device, and an electroluminescence display device. The image display device may have a touch panel function. The flexible laminate is suitable for a flexible image display device that can be bent or bent. In the image display device, when the flexible laminate has a front panel, the flexible laminate is disposed on the viewing side of the image display device so that the front panel faces outward (the side opposite to the image display element side, i.e., the viewing side).

The image display device can be used as mobile equipment such as a smart phone and a tablet personal computer, a television, a digital photo frame, a digital label, a measuring instrument, instruments, office equipment, medical equipment, computer equipment and the like. The image display device of the present invention is suitable for flexible displays and the like because cracks are not easily visible even if the cracks occur in the retardation body due to bending.

Examples

[ measurement method ]

(measurement of layer thickness)

The thickness of each layer was measured using a contact type film thickness measuring apparatus ("MS-5C" manufactured by Nikon K.K.). The polarizer layer, the retardation layer and the alignment film were measured using a laser microscope (LEXT, manufactured by olympus corporation).

(measurement of internal haze value of adhesive layer)

One of the spacers laminated on both surfaces of the pressure-sensitive adhesive layer to be measured was peeled off, and the pressure-sensitive adhesive layer was bonded to the alkali-free glass. The other separator was peeled off. A transparent film (ZEONOR, ZF 14-013, manufactured by Zeon corporation, japan) was attached to the surface of the pressure-sensitive adhesive layer exposed by peeling of the separator to prepare a sample as a measurement target. The glass surface of the sample prepared above was irradiated with light, and the diffuse transmittance Td [% ] and the total light transmittance Tt [% ] were measured according to JIS K7136 using an integrating sphere type light transmittance measuring device (haze meter HM-150, manufactured by color technology research on murakamura, ltd). Then, the total haze value was calculated by the following formula (1). In the sample prepared as described above, the transparent film was bonded to the surface of the pressure-sensitive adhesive layer from which light was emitted, and therefore the surface haze value was regarded as zero. Therefore, the internal haze value can be regarded as the same value as the total haze value calculated by the formula (1).

Total haze value [% ]/% ]) x 100 formula (1)

(measurement of internal haze value of film)

One surface of the film to be measured was bonded to alkali-free glass using an adhesive, and an adhesive layer and a transparent film (ZEONOR, ZF 14-013, manufactured by Zeon corporation, japan) were bonded to the other surface to prepare a sample. The incident light on the glass surface of the sample thus prepared was measured for the diffuse transmittance Td [% ] and the total light transmittance Tt [% ] according to JIS K7136 using an integrating sphere type light transmittance measuring device (haze meter HM-150, manufactured by color technology research on village, ltd), and the total haze value of the sample was calculated using the above formula (1). Since the surface haze value and the internal haze value of the transparent film bonded to the film to be measured can be regarded as zero, a value obtained by subtracting the internal haze value of the pressure-sensitive adhesive layer used from the total haze value of the sample is regarded as the internal haze value of the film to be measured. The internal haze value of the pressure-sensitive adhesive layer used was measured by the method described above.

(calculation of internal haze value of front laminate)

In examples 1 to 4 and comparative examples 1 and 2, the layers of the front laminate were constituted as "front panel/1 st adhesive layer/protective layer/alignment film", and the internal haze value of the alignment film was regarded as zero, so the internal haze value of the front laminate was regarded as the total value of the internal haze values of the front panel, 1 st adhesive layer and protective layer. In addition, since the external haze value of the front panel may be regarded as zero, the total haze value of the front laminate may be regarded as being identical to the internal haze value of the front laminate.

(measurement of internal haze value of Flexible laminate)

A sample of a layer composition of "alkali-free glass/adhesive layer a/flexible laminate/adhesive layer B/transparent film" was prepared by bonding one surface of the flexible laminate to alkali-free glass using an adhesive layer (hereinafter referred to as "adhesive layer a"), and bonding an adhesive layer (hereinafter referred to as "adhesive layer B") and a transparent film (ZEONOR, ZF 14-013, manufactured by Zeon corporation, japan). The incident light on the glass surface of the sample thus prepared was measured for the diffuse transmittance Td [% ] and the total light transmittance Tt [% ] according to JIS K7136 using an integrating sphere type light transmittance measuring device (haze meter HM-150, manufactured by color technology research on village, ltd), and the total haze value of the sample was calculated using the above formula (1). Since the surface haze value and the internal haze value of the alkali-free glass and the transparent film bonded to the flexible laminate to be measured can be regarded as zero, a value obtained by subtracting the internal haze values of the pressure-sensitive adhesive layer a and the pressure-sensitive adhesive layer B used from the total haze value of the sample is used as the internal haze value of the flexible laminate to be measured. The internal haze values of the pressure-sensitive adhesive layers a and B used were measured by the method described in "measurement of internal haze value of pressure-sensitive adhesive layer" above.

(measurement of Transmission clarity of Flexible laminate)

Light was made incident from the front panel side of the flexible laminate to be measured, and transmission sharpness was measured according to JIS K7105-1981 using a sharpness measuring machine (ICM-1T, manufactured by Suga testing machine Co., Ltd.). The transmission clarity value is the sum of the measured values at slit intervals of 0.125mm, 0.5mm, 1.0mm and 2.0 mm. A higher value of transmission sharpness means a higher transmission sharpness.

[ production of Flexible laminate ]

< layer constitution of Flexible laminate >

As examples 1 to 4 and comparative examples 1 and 2, a flexible laminate having a layer configuration of "front panel/1 st adhesive layer/protective layer/alignment film/polarizer layer/overcoat layer/2 nd adhesive layer/horizontal alignment film/1 st retardation layer (λ/4 retardation layer)/adhesive layer/2 nd retardation layer (positive C layer)/vertical alignment film" was produced.

< manufacture of front Panel 1 >

(Polyamide-imide film)

14.67g (45.8mmol) of 2, 2' -bis (trifluoromethyl) benzidine (TFMB) and 233.3g of N, N-dimethylacetamide (DMAc) having a water content of 200ppm were put into a 1L separable flask equipped with a stirring blade under a nitrogen atmosphere, and TFMB was dissolved in DMAc while stirring at room temperature. Next, 4.283g (13.8mmol) of 4, 4' -oxydiphthalic dianhydride (OPDA) was added to the flask, and the mixture was stirred at room temperature for 16.5 hours. Thereafter, 1.359g (4.61mmol) of 4, 4' -oxybis (benzoyl chloride) (OBBC) and 5.609g (27.6mmol) of terephthaloyl chloride (TPC) were added to the flask, and stirred at room temperature for 1 hour. Then, 4.937g (48.35mmol) of acetic anhydride and 1.501g (16.12mmol) of 4-methylpyridine were put into a flask, and stirred at room temperature for 30 minutes, then heated to 70 ℃ using an oil bath, and further stirred for 3 hours to obtain a reaction solution.

After the obtained reaction solution was cooled to room temperature, 360g of methanol and 170g of ion-exchanged water were added to the reaction solution, thereby obtaining a precipitate of polyamideimide. This was immersed in methanol for 12 hours, recovered by filtration, and washed with methanol. Subsequently, the precipitate was dried under reduced pressure at 100 ℃ to obtain a polyamide imide (PAI) resin. DMAc was added to the polyamideimide resin to prepare a varnish. The varnish was applied and dried to form a polyamideimide film having a thickness of 50 μm.

(HC layer-Forming composition 1)

Composition 1 for forming a hard coat layer (HC layer) contained 30 parts by mass of a polyfunctional acrylate (Miramer M340, manufactured by mwon Specialty Chemical) and 50 parts by mass of a propylene glycol monomethyl ether dispersion of a nano silica sol (12nm, solid content 40%), 17 parts by mass of ethyl acetate, 2.7 parts by mass of a photopolymerization initiator (Irgacure-184, manufactured by Ciba Corporation) and 0.3 part by mass of a fluorine-based additive (KY1203, manufactured by shin-koku Corporation).

(front panel 1)

The HC layer-forming composition 1 was applied to one surface of a polyamideimide film, the obtained coating film was dried at 80 ℃ for 5 minutes, and UV light with an exposure of 500mJ/cm2(365nm basis) was irradiated using a UV irradiation apparatus (SPOT CURE SP-7, manufactured by Ushio electric Motor Co., Ltd.) to form an HC layer. The coating was performed so that the thickness after curing became 10.0 μm. The HC layer having a thickness of 10.0 μm after curing was formed on the other surface of the polyimide film in the same manner. The front panel 1 having a constitution of "HC layer (thickness 10 μm)/polyamideimide film (thickness 50 μm)/HC layer (thickness 10 μm)" was obtained as described above.

< preparation of composition for Forming polarizer layer >

(polymerizable liquid Crystal Compound)

As the polymerizable liquid crystal compound, a polymerizable liquid crystal compound represented by the formula (1-6) [ hereinafter, also referred to as compound (1-6) ] and a polymerizable liquid crystal compound represented by the formula (1-7) [ hereinafter, also referred to as compound (1-7) ] were used.

The compounds (1-6) and (1-7) were synthesized by the method described in Lub et al, Recl, Trav, Chim, Pays-Bas, 115, 321-328 (1996).

(dichroic dye)

As the dichroic dye, azo dyes described in examples of Japanese patent application laid-open No. 2013-101328 represented by the following formulae (2-1 a), (2-1 b), and (2-3 a) are used.

(composition for Forming polarizer layer)

The composition for forming a polarizer layer was prepared by mixing 75 parts by mass of the compound (1-6), 25 parts by mass of the compound (1-7), 2.5 parts by mass of each of the azo dyes represented by the above formulae (2-1 a), (2-1 b), and (2-3 a) as dichroic dyes, 6 parts by mass of 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure369, manufactured by BASF Japan) as a polymerization initiator, and 1.2 parts by mass of a polyacrylate compound (BYK-361N, manufactured by BYK-Chemie) as a leveling agent in 400 parts by mass of toluene as a solvent, and stirring the resulting mixture at 80 ℃ for 1 hour.

< production of adhesive layer >

(adhesive layer A, B)

An acrylic polymer was prepared by copolymerizing 70 parts by mass of n-butyl acrylate, 20 parts by mass of methyl acrylate, and 1.0 part by mass of acrylic acid. The weight average molecular weight Mw of the acrylic polymer was 1500000.

To 100 parts by mass of the obtained acrylic resin were mixed 0.3 part of a crosslinking agent ("Coronate L" manufactured by tokyo chemical corporation) and 0.5 part of a silane coupling agent ("X-12-981" manufactured by shin-Etsu chemical corporation), and ethyl acetate was added so that the total solid content concentration became 10%, to obtain a pressure-sensitive adhesive composition.

The obtained adhesive composition was applied by an applicator to a release-treated surface of a polyethylene terephthalate film (thickness: 38 μm) subjected to release treatment so that the dried thicknesses thereof became 25 μm (adhesive layer A) and 5 μm (adhesive layer B), respectively. The coating layer was dried at 100 ℃ for 1 minute to obtain a film having an adhesive layer. Thereafter, another polyethylene terephthalate film (38 μm in thickness) subjected to mold release treatment was attached to the exposed surface of the pressure-sensitive adhesive layer. Then, the mixture was aged at 23 ℃ and 50% RH relative humidity for 7 days to obtain sheet-like adhesive layers A and B having thicknesses of 25 μm and 5 μm. The internal haze values of the pressure-sensitive adhesive layers a and B were measured, and found to be 0.2%.

(adhesive layer C, D, E, F)

A urethane acrylate oligomer was added to a copolymer of butyl acrylate and acrylic acid, and silicone resin fine particles (trade name "TOSPEARL 130", manufactured by Momentive Performance Materials, average particle diameter 3.0 μm, refractive index 1.43) were added to an organic solvent solution containing an isocyanate-based crosslinking agent, and the mixture was sufficiently stirred to prepare a coating liquid for forming a pressure-sensitive adhesive layer. The internal haze values of the pressure-sensitive adhesive layers obtained by appropriately adjusting the blending amounts of the silicone resin fine particles were 17.3% (pressure-sensitive adhesive layer C), 30.8% (pressure-sensitive adhesive layer D), 44.2% (pressure-sensitive adhesive layer E), and 44.8% (pressure-sensitive adhesive layer F), respectively. The release-treated surface of the polyethylene terephthalate film (release film) having a thickness of 38 μm and subjected to release treatment was coated with a coating liquid for forming an adhesive layer, and dried to obtain a sheet-like adhesive layer C, D, E, F having a thickness of 25 μm. The internal haze values of the adhesive layers C, D, E, F were measured to be 17.3%, 30.8%, 44.2%, and 44.8%, respectively.

< preparation of protective layer >

A triacetyl cellulose film 1 (thickness 25 μm, internal haze value 0.5%, KC2UAW, hereinafter "TAC 1") was prepared, and a triacetyl cellulose film 2 (thickness 29 μm, internal haze value 3.0%, hereinafter "TAC 2") and a triacetyl cellulose film 3 (thickness 29.5 μm, internal haze value 12.3%, hereinafter "TAC 3") were further produced according to the production method described below.

The internal haze value and the total haze value of the protective layer of the present example were substantially the same.

(production of TAC 2)

A composition having a refractive index of 1.49 as a whole of a solid content was prepared by mixing 25 parts by mass of urethane acrylate (Miwon Co., Ltd., SC2153), 18.5 parts by mass of pentaerythritol triacrylate (Miwon Co., Ltd., M340), 2 parts by mass of light-transmitting fine particles (acrylic resin particles, average particle diameter 3 μ M), 50 parts by mass of methyl ethyl ketone (Daiki Co., Ltd.), 4 parts by mass of photoinitiator (I-184, manufactured by BASF Co., Ltd.), and 0.5 part by mass of a leveling agent (BYK Chemie, BYK 378). This composition was applied to one side of TAC1 (thickness 25 μm, internal haze value 0.5%, KC2UAW), and photocured after heat drying to produce TAC2 having a coating film thickness of 4 μm.

(production of TAC 3)

A composition having a refractive index of 1.49 was prepared by mixing 25 parts by mass of urethane acrylate (manufactured by Miwon Co., Ltd., SC2153), 18.5 parts by mass of pentaerythritol triacrylate (manufactured by Miwon Co., Ltd., M340), 2 parts by mass of light-transmitting fine particles (styrene-based resin particles having an average particle diameter of 4 μ M), 50 parts by mass of methyl ethyl ketone (manufactured by Daiki chemical Co., Ltd.), 4 parts by mass of photoinitiator (manufactured by BASF Co., Ltd., I-184) and 0.5 parts by mass of leveling agent (manufactured by BYK Chemie Co., Ltd., BYK 378). This composition was applied to one side of TAC1 (thickness 25 μm, internal haze value 0.5%, KC2UAW), and photocured after heat drying to produce TAC3 having a coating film thickness of 4.5 μm.

< preparation of lambda/4 layer >

(composition for Forming horizontal alignment film)

5 parts of a photo-alignment material (weight average molecular weight: 30000) having the following structure and 95 parts of cyclopentanone were mixed, and the resulting mixture was stirred at 80 ℃ for 1 hour to obtain a composition for forming a horizontally aligned film.

(composition for Forming retardation layer 1)

The following polymerizable liquid crystal compound A and polymerizable liquid crystal compound B were mixed at 90: 10.0 parts of a leveling agent (F-556; available from DIC Co., Ltd.) and 6 parts of 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one ("Irgacure 369(Irg 369)", available from BASF JAPAN Co., Ltd.) as a polymerization initiator were added to 100 parts of the mixture.

Further, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration became 13%, and the mixture was stirred at 80 ℃ for 1 hour to obtain a composition 1 for forming a retardation layer.

The polymerizable liquid crystal compound a is produced by the method described in japanese patent application laid-open No. 2010-31223. The polymerizable liquid crystal compound B is produced by the method described in Japanese patent laid-open No. 2009-173893. The respective molecular structures are shown below.

(polymerizable liquid Crystal Compound A)

(polymerizable liquid Crystal Compound B)

(lambda/4 phase difference layer)

A substrate film comprising a cycloolefin polymer (COP) film (ZF-14, manufactured by Zeon corporation, Japan, having a thickness of 23 μm) was subjected to corona treatment 1 time using a corona treatment apparatus (AGF-B10, manufactured by Chunshi electric Motor Co., Ltd.) at an output of 0.3kW and a treatment speed of 3 m/min. Surface of corona-treated substrate by bar coating machineThe composition for forming a horizontally oriented film is coated. The coated film was dried at 80 ℃ for 1 minute and irradiated at 100mJ/cm using a polarized UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Motor Co., Ltd.)²The polarized light UV exposure is performed. The thickness of the obtained horizontally oriented film was measured by a laser microscope (LEXT, manufactured by Olympus corporation), and it was 100 nm.

Next, the composition 1 for forming a retardation layer was passed through a PTFE film-forming filter (product No.; T300A025A, manufactured by Advantech Toyo Co., Ltd.) having a pore diameter of 0.2 μm under an atmosphere of room temperature of 25 ℃ and humidity of 30% RH, and coated on a substrate film with an alignment film kept at 25 ℃ by a bar coater. The coating film was dried at 120 ℃ for 1 minute, and then irradiated with light (wavelength: 365nm, cumulative light amount at wavelength 365 nm: 1000mJ/cm under nitrogen atmosphere) from a high-pressure mercury lamp (Unicure VB-15201 BY-A, manufactured BY Ushio Motor Co., Ltd.)²) Ultraviolet rays, thereby producing an optical film. The thickness of the obtained coating film was measured by a laser microscope (LEXT, manufactured by Olympus corporation), and it was 2 μm.

In this manner, a laminate (retardation plate 1) in which a layer obtained by curing a polymerizable liquid crystal compound (λ/4 layer), a horizontal alignment film, and a base film were sequentially laminated was obtained. The retardation plate 1 exhibits reverse wavelength dispersion.

< preparation of Positive C layer >

(composition for Forming vertical alignment film)

As the composition for forming a vertically aligned film, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate and bis (2-vinyloxyethyl) ether were used in a weight ratio of 1: 1: 4: 5, and 4% of LUCIRIN TPO as a polymerization initiator.

(composition for Forming retardation layer 2)

The composition 2 for forming a retardation layer is prepared by adjusting a photopolymerizable nematic liquid crystal compound (RMM 28B, Merck) and a solvent so that the solid content becomes 1 to 1.5 g. The solvent used was Methyl Ethyl Ketone (MEK), methyl isobutyl ketone (MIBK) and Cyclohexanone (CHN) at a mass ratio (MEK: MIBK: CHN) of 35: 30: 35 in the above ratio.

(Positive C layer)

A polyethylene terephthalate (PET) film having a thickness of 38 μm was prepared as a base film. A composition for forming a vertically aligned film was applied to one surface of a substrate film so that the film thickness became 3 μm, and the substrate film was irradiated with 200mJ/cm²The above ultraviolet ray was used to prepare a vertically aligned film.

The composition for forming a retardation layer 2 was coated on the vertically aligned layer by die coating. The coating amount is 4-5 g (wet). The coating film was dried at a drying temperature of 75 ℃ for a drying time of 120 seconds. Thereafter, the coating film is irradiated with Ultraviolet (UV) rays to polymerize the polymerizable liquid crystal compound. The thickness of the obtained coating film was measured by a laser microscope (LEXT, manufactured by Olympus corporation), and found to be 1 μm.

In this manner, a laminate (phase difference plate 2) in which a layer (positive C layer) obtained by curing a polymerizable liquid crystal compound, a vertical alignment film, and a base film were sequentially laminated was obtained. The total thickness of the layer of the retardation plate 2 obtained by curing the polymerizable liquid crystal compound and the alignment film was 4 μm.

< phase difference body >

The retardation plate 1 and the retardation plate 2 were bonded to each other via an adhesive layer so that the surface opposite to the surface on the base film side was a bonding surface, thereby obtaining a retardation body having a layer of "base film/horizontal alignment film/1 st retardation layer (λ/4 layer)/adhesive layer/2 nd retardation layer (positive C layer)/vertical alignment film/base film". In the retardation body, a cutting was linearly scribed from the surface of the substrate film side on the positive C layer side through the positive C layer and the λ/4 layer to a depth of the horizontally oriented film by using a cutter, and cracks generated during bending were simulated.

[ example 1]

The composition for forming an alignment film was coated on TAC3 by a bar coating method. The coating film was dried at 80 ℃ for 1 minute. Then, the coating film was irradiated with polarized UV light using the UV irradiation apparatus and the wire grid to impart alignment properties to the coating film. The exposure amount was 100mJ/cm²(365nm reference). UIS-27132 # # (manufactured by Ushio electric Co., Ltd.) was used for the wire grid. An alignment film is formed in this manner. The thickness of the alignment film is100nm。

The composition for forming a polarizer was coated on the formed alignment film by a bar coating method. The coating film was dried by heating at 100 ℃ for 2 minutes and then cooled to room temperature. Using the above UV irradiation apparatus, the cumulative light amount was 1200mJ/cm²The coating film was irradiated with ultraviolet light (365nm basis) to form a polarizer layer. The thickness of the resulting polarizer layer was 3 μm. A composition comprising polyvinyl alcohol and water was applied to the polarizer layer in such a manner that the thickness after drying became 0.5 μm, and dried at a temperature of 80 ℃ for 3 minutes to form an overcoat layer. In this manner, a linear polarizing plate having a layer of "substrate film/alignment film/polarizer layer/overcoat layer" was produced.

One surface of the front panel 1 and the surface of the pressure-sensitive adhesive layer a exposed by peeling one polyethylene terephthalate film of the film provided with the pressure-sensitive adhesive layer a were subjected to corona treatment, and then the two were bonded.

Next, the surface of the pressure-sensitive adhesive layer a exposed by peeling the other polyethylene terephthalate film from the pressure-sensitive adhesive layer a and the surface of the linear polarizing plate on the substrate film side were subjected to corona treatment, and then the two were bonded. Then, the surface of the linear polarizing plate on the outer coating layer side and the surface of the pressure-sensitive adhesive layer B exposed by peeling one polyethylene terephthalate film of the film provided with the pressure-sensitive adhesive layer B were subjected to corona treatment, and then the two were bonded. Next, another polyethylene terephthalate film was peeled off from the adhesive layer B to expose the adhesive layer B. In this way, a laminate having a constitution of "front panel 1/adhesive layer a/substrate film (protective layer)/alignment film/polarizer layer/overcoat layer/adhesive layer B" was obtained.

The substrate film on the 1 st retardation layer (λ/4 layer) side was peeled from the above-mentioned retardation body to expose the horizontal alignment film, and was bonded to the pressure-sensitive adhesive layer B. The absorption axis of the polarizer layer makes an angle of 45 with the slow axis of the lambda/4 layer. Next, the substrate film on the 2 nd retardation layer (positive C layer) side of the retardation body was peeled off to expose the vertical alignment film. In this manner, a flexible laminate of example 1 having a layer configuration of "front panel (front panel 1)/1 st adhesive layer (adhesive layer a)/protective layer (base film)/alignment film/polarizer layer/overcoat layer/2 nd adhesive layer (adhesive layer B)/horizontal alignment film/1 st retardation layer (λ/4 layer)/adhesive layer/positive C layer/vertical alignment film" was obtained.

Examples 2 to 4 and comparative examples 1 and 2

The flexible laminates of examples 2 to 4 and comparative examples 1 and 2 were produced in the same manner as in example 1, using the members shown in table 1 as the front sheet, the 1 st adhesive layer, the protective layer, and the 2 nd adhesive layer, and using the members similar to those in example 1.

[ evaluation method ]

With respect to the flexible laminate, the appearance was evaluated as follows for a cut (a cut simulating a crack) cut linearly from the surface on the vertical alignment film side up to the depth of the horizontal alignment film based on the transmitted light and the reflected light.

(crack visibility (reflected light))

The flexible laminate was placed on a blackboard in a dark room with the front panel side facing upward, and the flexible laminate was irradiated from above by lighting a fluorescent lamp, and the appearance of a cut based on the reflected light was evaluated according to the following criteria. The evaluation results are shown in table 1.

(crack visibility (transmitted light))

A fluorescent lamp was lit on the back side (vertical alignment film side) of the flexible laminate in a dark room, and the appearance of a cut on the front side based on the transmitted light was evaluated according to the following criteria. The evaluation results are shown in table 1.

(evaluation criteria)

A: the cut mark can not be seen visually,

b: the cut mark was slightly visually recognized and,

c: the cut was visually recognized.

[ Table 1]

Claims (7)

1. A flexible laminate comprising a polarizer layer, a front laminate provided in contact with the front surface of the polarizer layer, and a phase difference body provided on the side of the polarizer layer opposite to the front surface,

the front laminate has a total haze value of 5.0% or more.

2. The flexible laminate of claim 1, wherein the front laminate has an internal haze value of 5.0% or greater.

3. The flexible laminate of claim 1 or 2, wherein the front laminate comprises, in order from the polarizer layer side, a protective layer, a 1 st adhesive layer, a front panel.

4. The flexible laminate of any one of claims 1-3, wherein the phase retarder comprises a λ/4 layer.

5. The flexible laminate of claim 4, wherein the phase retarder further comprises a positive C layer or a λ/2 layer.

6. The flexible laminate according to any one of claims 1 to 5, further comprising a touch sensor panel on a side of the phase difference body opposite to the polarizer layer side.

7. An image display device comprising the flexible laminate according to any one of claims 1 to 6.

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