JP2022046029A - Optical laminate - Google Patents

Abstract

To provide an optical laminate capable of suppressing corrosion of a metal layer under a high-temperature and high-humidity environment.SOLUTION: An optical laminate comprises a linear polarizing layer, a retardation layer, a barrier layer, and an adhesive layer in this order. The linear polarizing layer is a polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented. The retardation layer comprises at least one cured product layer obtained by polymerizing and curing a polymerizable liquid crystal compound. The barrier layer is provided in direct contact with the adhesive layer. The moisture permeability of the barrier layer at a temperature of 40°C and a relative humidity of 90%RH is 1 g/m2/24 hr or more and 2000 g/m2/24 hr or less. The distance from the surface of the linearly polarizing layer on the retardation layer side to the surface of the adhesive layer on the side opposite to the barrier layer side is 55 μm or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical laminate.

The polarizing plate is used as one of the optical components constituting a display device such as a liquid crystal display device or an organic EL display device. The polarizing plate usually has a laminated structure in which a protective layer is laminated on one side or both sides of a linear polarizing layer, and is incorporated in a display device with this laminated structure. Further, in a touch panel type display device mainly used for portable information terminals such as smartphones and tablets, a conductive layer for forming a touch sensor may be provided between the polarizing plate and the image display element. It is known (for example, Patent Documents 1 to 3 and the like).

In recent years, in order to improve the design of a display device, it has been required to make the entire display device thinner. Further, when the display device is folded or wound like a flexible display, the smaller the thickness of the display device, the smaller the stress generated by the folding or winding, and the occurrence of defects can be suppressed. Therefore, it is required to reduce the number of members used by thinning various members used in the display device and integrating the functions.

Japanese Unexamined Patent Publication No. 2015-52765 Japanese Unexamined Patent Publication No. 2015-172740 International Publication No. 2020/11232

When a metal layer is used as the conductive layer for constituting the touch sensor, the metal layer is corroded in a high temperature and high humidity environment when the distance between the linear polarizing layer and the metal layer is reduced due to the thinning of the display device. It was found to be more likely to occur.

INDUSTRIAL APPLICABILITY The present invention is an optical laminate capable of suppressing corrosion of a metal layer in a high temperature and high humidity environment even when the display device is made thinner by thinning and / or reducing various members used in the display device. The purpose is to provide.

The present invention provides the following optical laminates.
[1] An optical laminate including a linear polarizing layer, a retardation layer, a barrier layer, and an adhesive layer in this order.
The linear polarizing layer is a polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented.
The retardation layer contains at least one cured product layer obtained by polymerizing and curing the polymerizable liquid crystal compound.
The barrier layer is provided in direct contact with the pressure-sensitive adhesive layer.
The moisture permeability of the barrier layer at a temperature of 40 ° C. and a relative humidity of 90% RH is 1 g / m ^2/24 hr or more and 2000 g / m ^2/24 hr or less.
An optical laminate having a distance from the surface of the linear polarizing layer on the retardation layer side to the surface of the pressure-sensitive adhesive layer on the side opposite to the barrier layer side of 55 μm or less.
[2] The optical laminate according to [1], wherein the amount of iodine in the pressure-sensitive adhesive layer after the optical laminate is stored at a temperature of 85 ° C. and a relative humidity of 85% RH for 240 hours is 250 ppm or less. ..
[3] The optical laminate according to [1] or [2], wherein the barrier layer is a resin film.
[4] The retardation layer is
It contains two layers of the cured product and contains two layers.
The optical laminate according to any one of [1] to [3], further comprising a bonding layer (X) for bonding the two cured product layers to each other.
[5] The optical laminate according to [4], wherein the bonding layer is an adhesive layer.
[6] Further, a polarizing plate including the linear polarizing layer and a bonding layer (Y) for bonding the polarizing plate and the retardation layer are included.
The optical laminate according to any one of [1] to [5], wherein the polarizing plate is provided with a protective layer on one side or both sides of the linear polarizing layer.
[7] The optical laminate according to any one of [1] to [6], further comprising a bonding layer (Z) for bonding the retardation layer and the barrier layer.
[8] The optical laminate according to [7], wherein the bonded layer (Z) is an adhesive layer.
[9] The optical laminate according to any one of [1] to [8], further comprising a metal layer on the side of the pressure-sensitive adhesive layer opposite to the barrier layer side.
[10] The optical laminate according to [7], wherein the metal layer is provided in direct contact with the pressure-sensitive adhesive layer.

The optical laminate of the present invention can suppress corrosion of the metal layer in a high temperature and high humidity environment even when the display device is made thinner by thinning and / or reducing the thickness of various members used in the display device. can.

It is a schematic sectional drawing schematically showing an example of the optical laminated body of this invention. It is a schematic sectional drawing schematically showing another example of the optical laminated body of this invention. It is a schematic sectional drawing schematically showing still another example of the optical laminated body of this invention. It is a schematic sectional drawing schematically showing still another example of the optical laminated body of this invention. It is a schematic sectional drawing schematically showing still another example of the optical laminated body of this invention. It is a schematic sectional drawing schematically showing still another example of the optical laminated body of this invention.

Hereinafter, preferred embodiments of the optical laminate and the peeling method of the present invention will be described with reference to the drawings. All of the following drawings are provided to aid understanding of the present invention, and the size and shape of each component shown in the drawings may not necessarily match the size and shape of the actual component.

(Optical laminate)
1 to 6 are schematic cross-sectional views schematically showing an example of the optical laminate of the present embodiment. The optical laminates 1a to 1f of the present embodiment (hereinafter, these may be collectively referred to as “optical laminate 1”) include a linear polarizing layer 31, a retardation layer 10, a barrier layer 4, and an adhesive layer 5. Is included in this order. The linear polarizing layer 31 is a polyvinyl alcohol-based resin film (hereinafter, may be referred to as “PVA-based film”) in which iodine is adsorbed and oriented. The retardation layer 10 includes at least one cured product layer (first cured product layer 11, second cured product layer 12, etc., which will be described later) in which the polymerizable liquid crystal compound is polymerized and cured. The barrier layer 4 is provided in direct contact with the pressure-sensitive adhesive layer 5. The moisture permeability of the barrier layer 4 at a temperature of 40 ° C. and a relative humidity of 90% RH is 1 g / m ^2/24 hr or more and 2000 g / m ^2/24 hr or less. The optical laminate 1 has a distance D of 55 μm or less from the surface of the linear polarizing layer 31 on the retardation layer 10 side to the surface of the pressure-sensitive adhesive layer 5 on the side opposite to the barrier layer 4 side.

The optical laminate 1 may further include a metal layer 6 on the side opposite to the barrier layer 4 side of the pressure-sensitive adhesive layer 5, as in the optical laminates 1e and 1f shown in FIGS. 5 and 6. The metal layer 6 is preferably provided in direct contact with the pressure-sensitive adhesive layer 5.

In the optical laminate 1 having the above-mentioned layer structure, corrosion that occurs in the metal layer 6 when the optical laminates 1a to 1d are laminated on the metal layer 6 via the pressure-sensitive adhesive layer 5 or in the optical laminates 1e and 1f. In particular, pitting corrosion generated in the metal layer 6 can be suppressed. The reason why the optical laminate 1 can suppress the corrosion of the metal layer 6 is presumed as follows. In a PVA-based film in which iodine is adsorbed and oriented as a linear polarizing layer, a small amount of iodine may exude from the PVA-based film in a high-temperature and high-humidity environment. In a laminate containing a linearly polarized light layer and a metal layer, it is considered that iodine exuded from the linearly polarized light layer corrodes the metal layer when it reaches the metal layer. Therefore, in the optical laminate 1, a barrier layer 4 having a moisture permeability in the above range is provided so as to be in contact with the pressure-sensitive adhesive layer 5 for bonding to the metal layer 6. As a result, even in the thin optical laminate 1 having a distance D of 55 μm or less, it is possible to prevent iodine exuded from the linear polarizing layer 31 from reaching the metal layer 6, and the metal layer 6 is corroded. It is thought that it can be suppressed.

As shown in FIGS. 1 to 6, the optical laminate 1 has protective layers 32 and 33 on one side or both sides of the linear polarizing layer 31 (hereinafter, "first protective layer 32" and "second protective layer 33", respectively. It may include a polarizing plate 30 having a). From the viewpoint of reducing the thickness of the optical laminate 1, the polarizing plate 30 preferably has the first protective layer 32 or the second protective layer 33 on only one side of the linear polarizing layer 31. When the protective layer is provided on only one side of the linearly polarized light layer 31, the first first side of the linearly polarized light layer 31 opposite to the retardation layer 10 side as shown in FIGS. 1 and 2 from the viewpoint of protecting the linearly polarized light layer 31. It is preferable to have the protective layer 32. Since the optical laminate 1 has the barrier layer 4, the first protective layer 32 is provided, and even when the second protective layer 33 is not provided, the corrosion of the metal layer 6 is effectively suppressed. be able to. The first protective layer 32 and / or the second protective layer 33 is placed on the linear polarizing layer 31 via the first bonded layer 21 and / or the second bonded layer 22, as shown in FIGS. 1 to 6, for example. It may be provided. The first bonding layer 21 and the second bonding layer 22 are an adhesive layer or an adhesive layer.

The optical laminate 1 may further include a bonding layer (Y) 23 for bonding the linear polarizing layer 31 or the polarizing plate 30 and the retardation layer 10. In this case, the retardation layer 10 is provided on the linear polarizing layer 31 or the polarizing plate 30 via the bonding layer (Y) 23, for example, as shown in FIGS. 1 to 6. The bonding layer (Y) 23 is an adhesive layer or an adhesive layer. Alternatively, the retardation layer 10 may be provided so as to be in direct contact with the linear polarizing layer 31 or the polarizing plate 30.

The optical laminate 1 may further include a bonding layer (Z) 24 for bonding the retardation layer 10 and the barrier layer 4. In this case, the barrier layer 4 is provided on the retardation layer 10 via the bonding layer (Z) 24, for example, as shown in FIGS. 1 to 6. The bonding layer (Z) 24 is an adhesive layer or an adhesive layer. Alternatively, the barrier layer 4 may be provided so as to be in direct contact with the retardation layer 10. When the optical laminate 1 includes the bonding layer (Z) 24, the bonding layer (Z) 24 is preferably an adhesive layer. Thereby, for example, when the optical laminated body 1 is cut by a cutting blade, it is possible to suppress the deformation of the retardation layer 10 in the cut surface.

In the optical laminate 1, the distance D is 55 μm or less, may be 48 μm or less, may be 45 μm or less, may be 40 μm or less, may be 35 μm or less, and may be 30 μm or less. It may be present, and may be 25 μm or less. The distance D is usually 10 μm or more, may be 15 μm or more, or may be 20 μm or more.

The amount of iodine in the pressure-sensitive adhesive layer after the optical laminate 1 is stored under the conditions of a temperature of 85 ° C. and a relative humidity of 85% RH for 240 hours is preferably 250 ppm or less, more preferably 200 ppm or less. It is more preferably 150 ppm or less, further preferably 100 ppm or less, 50 ppm or less, 30 ppm or less, or 10 ppm or less. When the amount of iodine is within the above range, corrosion of the metal layer 6 when the optical laminate 1 is exposed to a high temperature and high humidity environment is likely to be suppressed. For the iodine amount, for example, the linear polarizing layer 31 is provided with the first protective layer 32 and / or the second protective layer 33, which adjusts the moisture permeability of the barrier layer 4, the first protective layer 32 and / or the second protection. It can be adjusted by adjusting the type and thickness of the layer 33 and the like. The iodine amount can be measured by the method described in Examples described later.

The optical laminates 1a to 1d shown in FIGS. 1 to 4 may have a release film on the side opposite to the retardation layer 10 side of the pressure-sensitive adhesive layer 5. The release film covers and protects the pressure-sensitive adhesive layer 5, or supports the pressure-sensitive adhesive layer 5, and has a function as a separator that can be peeled off from the pressure-sensitive adhesive layer 5. Examples of the release film include a film in which the surface of the base film on the pressure-sensitive adhesive layer side is subjected to a mold release treatment such as a silicone treatment. Examples of the resin material forming the base film include the resin material forming the protective layer described later. The resin film may have a one-layer structure or may be a multilayer resin film having a multilayer structure of two or more layers.

The optical laminates 1a to 1d shown in FIGS. 1 to 4 can form a circular polarizing plate and can be used as an antireflection film in an organic EL (electroluminescence) display device or the like. When the optical laminates 1a to 1d are circular polarizing plates, at least one of the cured product layers contained in the retardation layer 10 is preferably a layer having a λ / 4 wavelength retardation characteristic. As shown in FIGS. 2, 4, and 6, when the retardation layer 10 includes the first cured product layer 11 and the second cured product layer 12, the first cured product layer 11 and the second cured product layer 12 are formed. [I] 1/2 wavelength retardation layer and 1/4 wavelength retardation layer, [ii] 1/4 wavelength retardation layer and positive C plate, or [iii] positive C plate and 1/4 wavelength position, respectively. It may be a phase difference layer. The λ / 4 wavelength retardation layer may have a reverse wavelength dispersibility.

The optical laminate 1 can be used for a display device such as a smartphone or a tablet, and can be particularly preferably used for a touch panel type display device. Examples of the display device include an organic EL display device, a liquid crystal display device, and the like. The display device may be a flexible display.

Hereinafter, details of each member used in the optical laminate 1 will be described.
(Linear polarizing layer)
The linearly polarized light layer has a property of transmitting linearly polarized light having a vibration plane orthogonal to the absorption axis when unpolarized light is incident. The linear polarizing layer is a PVA-based film in which iodine is adsorbed and oriented.

The linear polarizing layer is, for example, a PVA-based film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, an ethylene-vinyl acetate copolymer partially saponified film, which has been dyed with iodine and stretched. Can be mentioned. If necessary, a PVA-based film in which iodine is adsorbed and oriented by a dyeing treatment may be treated with a boric acid aqueous solution, and then a washing step of washing off the boric acid aqueous solution may be performed. A known method can be adopted for each step.

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

The degree of saponification of the PVA-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The PVA-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The average degree of polymerization of the PVA-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000. The average degree of polymerization of the PVA-based resin can be determined in accordance with JIS K 6726 (1994). If the average degree of polymerization is less than 1000, it is difficult to obtain preferable polarization performance, and if it exceeds 10,000, the film processability may be inferior.

The method for producing a linear polarizing layer containing a PVA-based film is to prepare a base film, apply a resin solution such as PVA-based resin on the base film, and dry the base film to remove the solvent. May include a step of forming a resin layer. A primer layer can 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 thermoplastic resin that can be used for the protective layer described later can be used. Examples of the material of the primer layer include a resin obtained by cross-linking a hydrophilic resin used for the linear polarizing layer.

Then, if necessary, the amount of solvent such as water content of the resin layer is adjusted, then the base film and the resin layer are uniaxially stretched, and then the resin layer is dyed with iodine to adsorb and orient the iodine on the resin layer. .. Next, if necessary, the resin layer in which iodine is adsorbed and oriented is treated with a boric acid aqueous solution, and then a washing step of washing off the boric acid aqueous solution is performed. As a result, a film of a resin layer in which iodine is adsorbed and oriented, that is, a linear polarizing layer is produced. A known method can be adopted for each step.

The amount of boric acid in the boric acid-containing aqueous solution for treating the PVA-based film or resin layer in which iodine is adsorbed and oriented is usually about 2 to 15 parts by weight per 100 parts by weight of water, preferably 5 to 12 parts by weight. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually about 0.1 to 15 parts by weight, preferably about 5 to 12 parts by weight, per 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 ° C. or higher, preferably 50 to 85 ° C., more preferably 60 to 80 ° C.

The PVA-based film and the uniaxial stretching of the base film and the resin layer may be performed before dyeing, during dyeing, or during boric acid treatment after dyeing, and these may be performed. Uniaxial stretching may be performed at each of a plurality of stages. The PVA-based film, the base film, and the resin layer may be uniaxially stretched in the MD direction (film transport direction), and in this case, may be uniaxially stretched between rolls having different peripheral speeds, or a thermal roll. May be uniaxially stretched using. Further, the PVA-based film, the base film and the resin layer may be uniaxially stretched in the TD direction (direction perpendicular to the film transport direction), and in this case, the so-called tenter method can be used. Further, the stretching may be a dry stretching in which stretching is performed in the atmosphere, or a wet stretching in which the PVA-based film or the resin layer is swollen with a solvent. In order to exhibit the performance of the linear polarizing layer, the draw ratio is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times or more. There is no particular upper limit to the draw ratio, but it is preferably 8 times or less from the viewpoint of suppressing breakage and the like.

The linear polarizing layer produced by the manufacturing method using the base film can be obtained by laminating the protective layer described later and then peeling off the base film. According to this method, the linear polarizing layer can be further thinned.

The thickness of the linear polarizing layer is preferably 1 μm or more, preferably 2 μm or more, 5 μm or more, preferably 30 μm or less, and more preferably 15 μm or less. It is more preferably 10 μm or less, and may be 8 μm or less. The smaller the thickness of the linear polarizing layer, the easier it is for iodine to seep out in a high temperature and high humidity environment. Therefore, when the thickness of the linear polarizing layer is small, the corrosion generated in the metal layer 6 can be effectively suppressed by using the optical laminate 1 of the present embodiment.

In the washing step of treating a PVA-based film or resin layer in which iodine is adsorbed and oriented with a boric acid aqueous solution and then washing off the boric acid aqueous solution, the lower the boric acid concentration in the boric acid aqueous solution, the higher the iodine in a high temperature and high humidity environment. Is easy to seep out. Therefore, when the boric acid concentration in the above-mentioned boric acid aqueous solution used in the manufacturing process of the linear polarizing layer is low, the corrosion generated in the metal layer 6 is effective by using the optical laminate 1 of the present embodiment. Can be suppressed.

(Polarizer)
As shown in FIGS. 1 to 6, the linear polarizing layer 31 can be formed into a polarizing plate 30 by laminating a protective layer (first protective layer 32 and / or second protective layer 33) on one or both sides thereof. .. The polarizing plate 30 is a so-called linear polarizing plate. Examples of the first protective layer 32 and / or the second protective layer 33 that can be laminated on one or both sides of the linear polarizing layer 31 include transparency, mechanical strength, thermal stability, moisture barrier property, and isotropic property. , A film formed of a thermoplastic resin having excellent stretchability and the like is used. Specific examples of the thermoplastic resin include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether sulfone resins; polysulfone resins; polycarbonate resins; polyamide resins such as nylon and aromatic polyamides; polyimides. Resin; Polyethylene resin such as polyethylene, polypropylene, ethylene / propylene copolymer; Cyclic polyolefin resin having cyclo-based and norbornene structure (also referred to as norbornene-based resin); (meth) acrylic resin; polyallylate resin; polystyrene resin; polyvinyl alcohol Resins, as well as mixtures thereof, can be mentioned. The resin composition of the first protective layer 32 and the second protective layer 33 may be the same or different. In addition, in this specification, "(meth) acrylic" means that either acrylic or methacrylic may be used. "(Meta)" such as (meth) acrylate has the same meaning.

The moisture permeability of the first protective layer 32 and the second protective layer 33 at a temperature of 40 ° C. and a relative humidity of 90% RH is not particularly limited. In the optical laminate 1 of the present embodiment, it is effective when the moisture permeability of the first protective layer 32 is 300 g / m ^2/24 hr or less, and the moisture permeability of the first protective layer 32 is 100 g / m. When it is ^2/24 hr or less, the corrosion of the metal layer can be suppressed more effectively. When the moisture permeability of the first protective layer 32 becomes small, iodine in the linear polarizing layer 31 becomes difficult to move to the first protective layer 32 side in the optical laminated body 1, and easily moves to the pressure-sensitive adhesive layer 5 side. Since the optical laminate 1 has the barrier layer 4, even if iodine easily moves to the pressure-sensitive adhesive layer 5 side as described above, the metal layer provided on the side opposite to the barrier layer 4 side of the pressure-sensitive adhesive layer 5 is provided. It is possible to prevent 6 from corroding. The moisture permeability of the first protective layer 32 and the second protective layer 33 can be measured by a moisture permeability test method (cup method, JIS Z 0208).

The first protective layer 32 and the second protective layer 33 may have retardation characteristics, or may be optical functional layers having functional characteristics such as a hard coat layer and an antireflection layer. The thickness of the first protective layer 32 and the second protective layer 33 is preferably 3 μm or more, more preferably 5 μm or more, preferably 50 μm or less, and 30 μm or less, respectively. It is more preferable to have.

It is preferable that the first protective layer 32, the second protective layer 33, and the linear polarizing layer are bonded by the first bonded layer 21 and the second bonded layer 22, respectively (FIGS. 1 to 6). The first bonding layer 21 and the second bonding layer 22 are an adhesive layer or an adhesive layer. As the adhesive layer and the adhesive layer, those described later can be used. The first bonding layer 21 and the second bonding layer 22 are preferably adhesive layers formed by using a water-based adhesive described later.

(Phase difference layer)
The retardation layer 10 includes a layer having a retardation characteristic. Examples of the layer having the retardation characteristic include a cured product layer obtained by polymerizing and curing a polymerizable liquid crystal compound. The retardation layer 10 includes at least one cured product layer, and may include two or more cured product layers. When two or more cured product layers are included, the retardation layer 10 is a bonding layer for bonding the cured product layers to each other (for example, the bonded layer (X) shown in FIGS. 2, 4, and 6). 25) may be included. The cured product layer can be a 1/2 wavelength retardation layer, a 1/4 wavelength retardation layer, or a positive C plate. The 1/4 wavelength retardation layer may be reverse wavelength dispersive. When the retardation layer contains two or more cured product layers, the cured product layers may be the same as each other and have the retardation characteristics, or may have different retardation characteristics from each other.

Examples of the polymerizable liquid crystal compound include a rod-shaped polymerizable liquid crystal compound and a disk-shaped polymerizable liquid crystal compound, and one of them may be used, or a mixture containing both of them may be used. When the rod-shaped polymerizable liquid crystal compound is horizontally or vertically oriented with respect to the substrate layer, the optical axis of the polymerizable liquid crystal compound coincides with the long axis direction of the polymerizable liquid crystal compound. When the disk-shaped polymerizable liquid crystal compound is oriented, the optical axis of the polymerizable liquid crystal compound exists in a direction orthogonal to the disk surface of the polymerizable liquid crystal compound. As the rod-shaped polymerizable liquid crystal compound, for example, those described in JP-A No. 11-513019 (Claim 1 and the like) can be preferably used. Examples of the disk-shaped polymerizable liquid crystal compound are described in JP-A-2007-108732 (paragraphs [0020] to [0067], etc.) and JP-A-2010-244038 (paragraphs [0013] to [0108], etc.). Can be preferably used.

In order for the cured product layer formed by polymerizing the polymerizable liquid crystal compound to exhibit an in-plane retardation, the polymerizable liquid crystal compound may be oriented in an appropriate direction. When the polymerizable liquid crystal compound is rod-shaped, an in-plane phase difference is developed by orienting the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the substrate layer. It matches the direction. When the polymerizable liquid crystal compound is disk-shaped, an in-plane phase difference is developed by orienting the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the substrate layer. In this case, the optical axis and the slow axis Is orthogonal to. The orientation state of the polymerizable liquid crystal compound can be adjusted by the combination of the alignment layer and the polymerizable liquid crystal compound.

The polymerizable liquid crystal compound is a compound having at least one polymerizable group and having liquid crystallinity. When two or more kinds of polymerizable liquid crystal compounds are used in combination, it is preferable that at least one kind has two or more polymerizable groups in the molecule. The polymerizable group means a group involved in the polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in the polymerization reaction by an active radical, an acid, or the like generated from a photopolymerization initiator described later. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group, an oxetanyl group, a styryl group, an allyl group and the like. Be done. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The liquid crystal property of the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, and when the thermotropic liquid crystal is classified by order, it may be a nematic liquid crystal or a smectic liquid crystal.

When the retardation layer 10 includes a cured product layer of a polymerizable liquid crystal compound, the retardation layer 10 may include an alignment layer. The alignment layer has an orientation regulating force for orienting the polymerizable liquid crystal compound in a desired direction. The oriented layer may be a vertically oriented layer in which the molecular axis of the polymerizable liquid crystal compound is vertically oriented with respect to the base material layer, or the horizontally oriented layer in which the molecular axis of the polymerizable liquid crystal compound is horizontally oriented with respect to the base material layer. It may be a tilt-oriented layer in which the molecular axis of the polymerizable liquid crystal compound is tilt-aligned with respect to the base material layer. When the retardation layer includes two or more alignment layers, the alignment layers may be the same or different from each other.

The alignment layer has solvent resistance that does not dissolve due to coating of a liquid crystal layer forming composition containing a polymerizable liquid crystal compound, and has heat resistance to heat treatment for removing the solvent and orienting the polymerizable liquid crystal compound. The one is preferable. Examples of the oriented layer include an oriented polymer layer formed of an oriented polymer, a photo-oriented polymer layer formed of a photo-aligned polymer, and a grub-aligned layer having an uneven pattern or a plurality of grubs (grooves) on the layer surface. Can be done.

The thickness of the cured product layer may be 0.1 μm or more, 0.5 μm or more, 1 μm or more, 2 μm or more, and 10 μm or less. Is preferable, and it may be 8 μm or less, or 5 μm or less.

The cured product layer of the polymerizable liquid crystal compound can be formed by applying a liquid crystal layer forming composition containing the polymerizable liquid crystal compound on the base material layer, drying the composition, and polymerizing the polymerizable liquid crystal compound. The liquid crystal layer forming composition may be applied on the alignment layer formed on the base material layer.

As the base material layer, a film formed of a resin material can be used, and examples thereof include a film using the resin material described as the thermoplastic resin used for forming the protective layer described above. The thickness of the base material layer is not particularly limited, but is generally preferably 1 to 300 μm or less, more preferably 20 to 200 μm, and 30 to 120 μm from the viewpoint of workability such as strength and handleability. Is even more preferable. The base material layer may be incorporated into the optical laminate together with the cured product layer of the polymerizable liquid crystal compound, and the base material layer may be peeled off so that only the cured product layer of the polymerizable liquid crystal compound or the cured product layer and the base material layer can be incorporated. The alignment layer may be incorporated in the optical laminate. When the base material layer is incorporated into the optical laminate 1 together with the cured product layer of the polymerizable liquid crystal compound, the thickness of the base material layer may be less than 30 μm, for example, 25 μm or less.

The retardation layer 10 may be the first cured product layer 11 as shown in FIGS. 1, 3, and 5, and the first cured product layer as shown in FIGS. 2, 4, and 6. 11 and the second cured product layer 12 may be included, and in addition to the first cured product layer 11 and the second cured product layer 12, a bonding layer (X) 25 for bonding these is included. It may be a thing.

The bonding layer for bonding two or more cured product layers such as the bonding layer (X) 25 is a pressure-sensitive adhesive layer or an adhesive layer. The bonding layer is preferably an adhesive layer, more preferably an adhesive layer obtained by curing an active energy ray-curable adhesive, and further preferably an adhesive layer obtained by curing an ultraviolet curable adhesive. preferable. By using the bonded layer (X) 25 as an adhesive layer, it is possible to prevent wrinkles from being generated in the cured product layer when the optical laminate 1 is bent, folded, wound, or the like. ,preferable.

The thickness of the bonded layer is not particularly limited. When the bonding layer is an adhesive layer, the thickness is preferably 3 μm or more, preferably 10 μm or more, 15 μm or more, and preferably 30 μm or less, and 25 μm or less. It may be 20 μm or less. When the bonded layer is an adhesive layer, the thickness is preferably 0.1 μm or more, preferably 0.5 μm or more, and preferably 10 μm or less, and may be 5 μm or less. ..

The thickness of the retardation layer 10 depends on the total number of cured product layers contained in the retardation layer 10, but is usually 0.5 μm or more, may be 1 μm or more, or may be 2 μm or more. It may be 5 μm or more, preferably 50 μm or less, 30 μm or less, 15 μm or less, or 10 μm or less.

(Barrier layer)
The barrier layer 4 can be provided in order to prevent iodine in the linear polarizing layer 31 from moving to the pressure-sensitive adhesive layer 5 in the optical laminate 1. The moisture permeability of the barrier layer 4 at a temperature of 40 ° C. and a relative humidity of 90% RH is 1 g / m ^2/24 hr or more, may be 30 g / m ^2/24 hr or more, and is 100 g / m ^2/24 hr or more. It may be 200 g / m ^2/24 hr or more, or 500 g / m ^2/24 hr or more. The moisture permeability of the barrier layer is 2000 g / m ^2/24 hr or less, 1500 g / m ^2/24 hr or less, 1200 g / m ^2/24 hr or less, and 1000 g / m ^2/24 hr or less. It may be as follows. When the moisture permeability of the barrier layer 4 is less than 1 g / m ^2/24 hr, the optical deterioration of the linear polarizing layer 31 tends to be remarkable in a high temperature and high humidity environment, and when it exceeds 2000 g / m ^2/24 hr, the optical deterioration tends to be remarkable. Corrosion of the metal layer 6 tends to be difficult to be suppressed. The moisture permeability can be measured by a moisture permeability test method (cup method, JIS Z 0208) as described in Examples described later.

The barrier layer 4 is not particularly limited as long as it has the above-mentioned moisture permeability. The barrier layer 4 may be a resin film, an inorganic layer, or a cured resin layer obtained by curing an active energy ray-curable resin.

When the barrier layer 4 is a resin film, the resin film may have a single-layer structure or a multi-layer structure. Examples of the resin film include a film using the resin material described as the thermoplastic resin used for forming the protective layer described above. The resin film is preferably a cellulose resin film such as triacetyl cellulose; a cyclic polyolefin resin (also referred to as a norbornene-based resin) film having a cyclo-based and norbornene structure; and a (meth) acrylic resin film.

The resin film may have a phase difference characteristic such as a λ / 4 phase difference characteristic, but preferably does not have a phase difference characteristic (zero phase difference characteristic). Since the resin film does not have the phase difference characteristic, it is possible to suppress the influence on the optical characteristic of the optical laminate 1.

The thickness of the resin film may be selected according to the type of resin material constituting the resin film. The thickness of the resin film is, for example, preferably 1 μm or more, more preferably 4 μm or more, may be 8 μm or more, and is preferably 25 μm or less, more preferably 15 μm or less. .. If the thickness of the resin film is too large, there is a possibility that the optical characteristics may be deteriorated when the optical laminate 1 is bent.

When the barrier layer 4 is a resin film, it is preferable that the retardation layer 10 and the barrier layer 4 are bonded by the bonding layer (Z) 24. As described above, the bonding layer (Z) 24 is an adhesive layer or an adhesive layer. When the bonding layer (Z) 24 is an adhesive layer, the retardation layer 10 and the barrier layer have sufficient adhesive force even if the thickness is small, as compared with the case where the bonding layer (Z) 24 is used as an adhesive layer. It is preferable because it can be bonded to 4 and the distance D can be reduced.

When the barrier layer 4 is an inorganic layer, the inorganic layer may have a single-layer structure or a multi-layer structure. Examples of the inorganic material constituting the inorganic layer include metal oxides, metal nitrides, metal oxynitrides, and mixtures containing two or more of these. Metal atoms contained in the inorganic material include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), sodium (Na), boron (B), lead (Pb), and the like. Zirconium (Zr), yttrium (Y), and two or more of these atoms can be mentioned. The inorganic material may further contain a hydrogen atom (H), a phosphorus atom (P), a sulfur atom (S), a fluorine atom (F), a chlorine atom (Cl), and two or more of these atoms. ..

The inorganic layer can be formed by a known chemical vapor deposition method (CVD method), physical vapor deposition method (PVD method), or the like. Examples of the chemical vapor deposition method include a plasma chemical vapor deposition method using glow discharge plasma, a thermochemical vapor deposition method, a photochemical vapor deposition method, and the like. Examples of the physical vapor deposition method include a vacuum vapor deposition method, a sputtering method, an ion plating method, an ion cluster beam method, and the like.

The thickness of the inorganic layer is not particularly limited, and may be, for example, 1 nm or more, 10 nm or more, 30 nm or more, 1000 nm or less, or 300 nm or less. It may be 200 nm or less.

In the optical laminate 1, the inorganic layer may be formed directly on the surface of the retardation layer 10, or an inorganic layer may be formed on the base film and bonded to the retardation layer 10. As the base film, a film using a thermoplastic resin that can be used for the protective layer described above can be used.

When the barrier layer 4 is a cured resin layer, the cured resin layer can be formed by curing an active energy ray-curable resin. The resin cured layer may be an overcoat layer obtained by applying an active energy ray-curable resin to the surface of the retardation layer 10 and curing the resin. The active energy ray-curable resin is not particularly limited as long as it is a known active energy ray-curable resin, and examples thereof include an active energy ray-curable adhesive used for forming an adhesive layer described later. ..

The thickness of the cured resin layer is not particularly limited, and may be, for example, 0.5 μm or more, 1 μm or more, 10 μm or less, 5 μm or less, or 3 μm or less. It may be.

The barrier layer 4 is preferably a resin film. Compared to the inorganic layer, the resin film is considered to be able to suppress cracking during processing such as cutting the optical laminate 1 to a desired size or processing the end face of the optical laminate 1. Further, in the resin cured layer, it may be necessary to apply a thick active energy ray-curable resin in order to realize the above-mentioned moisture permeability. In this case, the curing heat generated by the curing of the active energy ray-curable resin causes the curing heat. There is a concern that wrinkles may occur in the optical laminate 1 or warpage may occur in the optical laminate 1. On the other hand, it is considered that the resin film can suppress the occurrence of the above-mentioned wrinkles and warpage as compared with the resin cured layer.

(Adhesive layer)
The pressure-sensitive adhesive layer 5 is a layer formed by using a pressure-sensitive adhesive. The pressure-sensitive adhesive exhibits adhesiveness by sticking itself to an adherend such as a metal layer, and is a so-called pressure-sensitive adhesive. Further, the active energy ray-curable pressure-sensitive adhesive described later can adjust the degree of cross-linking and the adhesive force by irradiating with energy rays.

The thickness of the pressure-sensitive adhesive layer 5 is preferably 5 μm or more and 30 μm or less, and more preferably 10 μm or more and 20 μm or less, from the viewpoint of bonding to an adherend such as the metal layer 6. When the thickness of the pressure-sensitive adhesive layer 5 arranged at a position close to the metal layer 6 is small, the iodine concentration of the pressure-sensitive adhesive layer 5 tends to be higher than that of a laminate not provided with the barrier layer 4. Therefore, by using the optical laminate 1 of the present embodiment, the corrosion generated in the metal layer 6 can be effectively suppressed.

As the pressure-sensitive adhesive, a conventionally known pressure-sensitive adhesive having excellent optical transparency can be used without particular limitation, and for example, a pressure-sensitive adhesive having a base polymer such as an acrylic type, a urethane type, a silicone type, or a polyvinyl ether type is used. be able to. Further, it may be an active energy ray-curable pressure-sensitive adhesive, a thermosetting pressure-sensitive adhesive or the like. Among these, a pressure-sensitive adhesive using an acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability (hereinafter, also referred to as reworkability), weather resistance, heat resistance, etc., is preferable. The pressure-sensitive adhesive layer is preferably composed of a reaction product of a pressure-sensitive adhesive containing a (meth) acrylic resin, a cross-linking agent, and a silane compound, and may contain other components.

The pressure-sensitive adhesive layer 5 may be formed by using an active energy ray-curable pressure-sensitive adhesive. The active energy ray-curable pressure-sensitive adhesive is a harder pressure-sensitive adhesive by blending the above-mentioned pressure-sensitive adhesive with an ultraviolet-curable compound such as a polyfunctional acrylate, forming a pressure-sensitive adhesive layer, and then irradiating the pressure-sensitive adhesive with ultraviolet rays to cure the pressure-sensitive adhesive. Layers can be formed. The active energy ray-curable pressure-sensitive adhesive has a property of being cured by being irradiated with energy rays such as ultraviolet rays and electron beams. Since the active energy ray-curable adhesive has adhesiveness even before irradiation with energy rays, it may adhere to an adherend such as a metal layer and be cured by irradiation with energy rays to adjust the adhesion force. It is a pressure-sensitive adhesive that has the property of being able to be used.

The active energy ray-curable pressure-sensitive adhesive generally contains an acrylic pressure-sensitive adhesive and an energy ray-polymerizable compound as main components. Usually, a cross-linking agent is further blended, and if necessary, a photopolymerization initiator, a photosensitizer, or the like can also be blended.

The storage elastic modulus of the pressure-sensitive adhesive layer 5 can be, for example, 50,000 Pa or less, may be 49,000 Pa or less, may be 40,000 Pa or less, and is preferably 10,000 Pa or more. .. When the storage elastic modulus of the pressure-sensitive adhesive layer 5 is within the above range, the adhesion to the metal layer 6 can be improved, for example. When the storage elastic modulus of the pressure-sensitive adhesive layer 5 is 50,000 Pa or less, it is possible to suppress the occurrence of floating between the pressure-sensitive adhesive layer 5 and the metal layer 6 under high-temperature drying or high-temperature and high-humidity conditions. In the present specification, the "storage elastic modulus of the pressure-sensitive adhesive layer" is a value measured at a temperature of 25 ° C. in accordance with JIS K7244-6, and can be measured by a commercially available viscoelasticity measuring device. As the viscoelasticity measuring device, for example, as shown in Examples described later, MCR300 manufactured by Physica can be used.

(Metal layer)
The metal layer 6 can be used as a conductive layer for forming a touch sensor of a touch panel. The metal layer 6 is a layer formed of one or more kinds of metals. The metal layer 6 may have a passivation film (oxide film) formed on its surface. The metal layer 6 may have a single-layer structure or a multi-layer structure. The passivation film is not counted as one layer.

Examples of the metal constituting the metal layer 6 include aluminum (Al), copper (Cu), gold (Au), silver (Ag), titanium (Ti), palladium (Pd), chromium (Cr), nickel (Ni), and the like. Tungsten (W), platinum (Pt), iron (Fe), indium (In), tin (Sn), iridium (Ir), rhodium (Rh), neodium (Nd), molybdenum (Mo), or metals thereof. Examples include alloys containing two or more types. Of these, the metal layer 6 is preferably made of aluminum or copper as a main component, and may contain titanium as an additive. Here, the main component means a metal that occupies 50% by mass or more of the metals constituting the metal layer 6.

The metal layer 6 can be formed on, for example, a translucent substrate, and may be a continuous film formed over the entire surface of the translucent substrate, or may be a continuous film formed on the surface of the translucent substrate. It may be a wiring layer. The metal wiring layer may be a metal mesh. The translucent base material may be any as long as it has translucency, and examples thereof include a film, a glass film, and a glass substrate using the resin material described as the thermoplastic resin used for forming the protective layer described above. Be done.

The method for forming the metal layer 6 is not particularly limited, and on the surface of the translucent substrate, for example, the above-mentioned chemical vapor deposition method, physical vapor deposition method, inkjet printing method, gravure printing method, electrolytic plating, electroless plating, etc. It may be formed by plating or the like. The metal layer 6 is preferably formed by a sputtering method.

The thickness of the metal layer 6 is usually 0.01 μm or more, may be 0.05 μm or more, and is preferably 3 μm or less, more preferably 1 μm or less, from the viewpoint of thinning. It is more preferably 0.8 μm or less.

When the metal layer 6 is a metal wiring layer, its line width is usually 10 μm or less, may be 5 μm or less, may be 3 μm or less, and is usually 0.5 μm or more.

(1st bonding layer, 2nd bonding layer, bonding layer (X), bonding layer (Y), bonding layer (Z), bonding layer)
Examples of the first and second bonding layers, bonding layers (X) to (Z), and bonding layers include an adhesive layer or an adhesive layer.

When each of the above-mentioned bonding layers is a pressure-sensitive adhesive layer, it can be formed by using the pressure-sensitive adhesive described in the above-mentioned pressure-sensitive adhesive layer. When each bonded layer is a pressure-sensitive adhesive layer, the storage elastic modulus of the pressure-sensitive adhesive layer is preferably 50,000 Pa or more, more preferably 100,000 Pa or more, and 150,000 Pa or more. Is even more preferable. From the viewpoint of suppressing the generation of bubbles when bonded, the storage elastic modulus of the pressure-sensitive adhesive layer is preferably 200,000 Pa or less. Since the storage elastic modulus of the pressure-sensitive adhesive layer is within the above range, it is possible to prevent wrinkles from being generated in the cured product layer when the optical laminate 1 is bent, folded, wound, or the like. ,preferable. The method for measuring the storage elastic modulus is as described above. When each bonding layer is a pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer is preferably 2 μm or more and 20 μm or less, and more preferably 4 μm or more and 17 μm or less.

When each of the above-mentioned bonded layers is an adhesive layer, it is considered that it is easier to suppress the corrosion of the metal layer 6 as compared with the case where these are adhesive layers. When each of the above-mentioned bonding layers is an adhesive layer, the adhesive layer can be formed by curing the curable component in the adhesive. Examples of the adhesive for forming the adhesive layer include adhesives other than pressure-sensitive adhesives (adhesives), such as water-based adhesives and active energy ray-curable adhesives.

Examples of the water-based adhesive include an adhesive in which a polyvinyl alcohol-based resin is dissolved or dispersed in water. The drying method when a water-based adhesive is used is not particularly limited, but for example, a method of drying using a hot air dryer or an infrared dryer can be adopted.

Examples of the active energy ray-curable adhesive include solvent-free active energy ray-curable adhesives containing curable compounds that are cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Can be mentioned. By using a solvent-free active energy ray-curable adhesive, the adhesion between layers can be improved.

The active energy ray-curable adhesive preferably contains one or both of a cationically polymerizable curable compound and a radically polymerizable curable compound because it exhibits good adhesiveness. The active energy ray-curable adhesive may further contain a cationic polymerization initiator such as a photocationic polymerization initiator for initiating the curing reaction of the curable compound, or a radical polymerization initiator.

Examples of the cationically polymerizable curable compound include an alicyclic epoxy compound having an epoxy group bonded to an alicyclic ring, and a polyfunctional aliphatic epoxy compound having two or more epoxy groups and having no aromatic ring. , Monofunctional epoxy group having one epoxy group (excluding those contained in alicyclic epoxy compounds), Epoxide type such as polyfunctional aromatic epoxy compound having two or more epoxy groups and aromatic ring Compounds; oxetane compounds having one or more oxetane rings in the molecule; combinations thereof.

Examples of the radically polymerizable curable compound include (meth) acrylic compounds (compounds having one or more (meth) acryloyloxy groups in the molecule), radically polymerizable double bonds, and others. Vinyl-based compounds of the above, or combinations thereof can be mentioned.

The active energy ray-curable adhesive may contain a sensitizer such as a photosensitizer, if necessary. By using the sensitizer, the reactivity can be improved, and the mechanical strength and the adhesive strength of the adhesive layer can be further improved. As the sensitizer, known ones can be appropriately applied. When the sensitizer is blended, the blending amount is preferably in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the total amount of the active energy ray-curable adhesive.

Active energy ray-curable adhesives include ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow regulators, plasticizers, defoamers, and antistatic agents, as needed. It can contain additives such as agents, leveling agents, and solvents.

When an active energy ray-curable adhesive is used, it is possible to irradiate active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays to cure the coating layer of the adhesive to form an adhesive layer. can. As the active energy ray, ultraviolet rays are preferable, and as a light source in this case, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, or the like may be used. can.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these examples. Hereinafter, the parts and% representing the blending amount or content are based on mass unless otherwise specified.

(1) Measurement method and evaluation method [Measurement of moisture permeability]
For the protective layer and barrier layer used in Examples and Comparative Examples, a humidity permeation test method (cup method, JIS) using a constant temperature and humidity chamber under the measurement conditions of a temperature of 40 ° C., a relative humidity of 90% RH, and a measurement time of 24 hours. The water vapor permeability was measured by (according to Z 0208), and this was taken as the moisture permeability.

[Measurement of iodine content in the adhesive layer]
The optical laminates obtained in Examples and Comparative Examples were cut into a size of 25 mm × 50 mm, and non-alkali glass was bonded onto a protective layer (COP film with HC) using an adhesive to form an adhesive layer (a). ) Was attached to the release film to prepare a test piece (1). The test piece (1) was stored in an oven at a temperature of 85 ° C. and a relative humidity of 85% RH for 240 hours, then the release film was peeled off and the pressure-sensitive adhesive of the pressure-sensitive adhesive layer (a) was scraped off. The amount of iodine [ppm] contained in the scraped adhesive was measured by an oxidative combustion ion chromatograph method performed under the following conditions.
<Sample combustion>
・ Equipment: AQF-2100H manufactured by Mitsubishi Chemical Analytech Co., Ltd.
-Combustion conditions: The combustion temperature was 1100 ° C., the gas flow rate was 200 mL / min for the argon flow rate, 400 mL / min for the oxygen flow rate, and 100 mL / min for the humidified air flow rate.
<Aeon Chroomatograph>
・ Equipment: Integration manufactured by Thermo Fisher Scientific Co., Ltd.
-Column: IonPac AS19 manufactured by Thermo Fisher Scientific
-Measurement conditions: The eluent was a KOH aqueous solution gradient, the flow rate was 1.0 mL / min, the injection amount was 100 μL, the measurement mode was a suppressor type, and the detector was an electrical conductivity detector.

[Measurement of storage elastic modulus of adhesive layer]
The storage elastic modulus of the pressure-sensitive adhesive layer used in Examples and Comparative Examples was measured by the following method. A plurality of sheets were laminated so that the thickness of the pressure-sensitive adhesive layer was 0.2 mm. The laminated pressure-sensitive adhesive layer was punched out so as to form a cylinder having a diameter of 8 mm, and this was used as a sample for measuring the storage elastic modulus. The storage elastic modulus [Pa] of the measurement sample was measured under the following conditions by a torsional shear method using a viscoelasticity measuring device (MCR300, manufactured by Physica) in accordance with JIS K7244-6.
<Measurement conditions>
・ Normal force FN: 1N
・ Distortion γ: 1%
・ Frequency: 1Hz
・ Temperature: 25 ℃

[Evaluation of corrosiveness of metal layer]
A glass substrate with a metal layer (manufactured by Geomatec Co., Ltd.) having a metal-aluminum layer having a thickness of about 500 nm formed on the surface of non-alkali glass by sputtering was prepared. Next, the optical laminates obtained in Examples and Comparative Examples were cut into a size of 50 mm × 60 mm, and the metal-aluminum layer side of the glass substrate with a metal layer was attached onto the pressure-sensitive adhesive layer (a) to form a protective layer. A test piece (2) was prepared by laminating non-alkali glass on (COP film with HC) using an adhesive. After storing the test piece (2) in an oven at a temperature of 85 ° C. and a relative humidity of 85% RH for 240 hours, the state of the metal layer of the test piece (2) (the part to which the cut piece of the optical laminate is attached). Was observed through a magnifying glass from the surface of the non-alkali glass on the protective layer side by shining light from the back surface of the glass substrate with a metal layer. In the observed metal layer, the number of pitting corrosion (pores having a diameter of 0.1 mm or more and capable of transmitting light) was counted and evaluated according to the following criteria.
A: The number of pitting corrosion is 4 or less,
B: The number of pitting corrosion is 5 or more and 20 or less.
C: More than 20 pitting corrosions have occurred.

(2) Preparation of each layer constituting the optical laminate [Preparation of active energy ray-curable adhesive]
The following components were mixed and mixed, and then defoamed to prepare an active energy ray-curable adhesive.
<Cation-polymerizable compound>
・ Neopentyl glycol diglycidyl ether (trade name: EX-211L, manufactured by Nagase ChemteX Corporation) 30 parts ・ 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (product) Name: OXT-221, manufactured by Toa Synthetic Co., Ltd. 13 parts, bisphenol A type epoxy resin (trade name: EP-4100E, ADEKA Co., Ltd., viscosity 13 Pa · s (temperature 25 ° C)) 12 parts, containing aromatics Oxetane compound (trade name: TCM-104, manufactured by TRONLY) 45 parts <photocationic polymerization initiator>
-CPI-100P, manufactured by San-Apro Co., Ltd., 50% propylene carbonate solution 2.25 parts (solid content)
<Photosensitizer>
・ 1,4-Diethoxynaphthalene 1 part

[Preparation of polarizing plate]
A polyvinyl alcohol film having a thickness of 20 μm, a degree of polymerization of 2,400, and a saponification degree of 99.9% or more was uniaxially stretched on a roll heated to 125 ° C. at a draw ratio of 4.5 times, and 28 while maintaining a tense state. After soaking in water at ° C. for 30 seconds, it was immersed in a dyeing bath at 28 ° C. containing 0.05 part of iodine and 5 parts of potassium iodide per 100 parts of water for 30 seconds. Then, it was immersed in a boric acid aqueous solution at 64 ° C. containing 5.5 parts of boric acid and 15 parts of potassium iodide per 100 parts of water for 110 seconds. Subsequently, it was immersed in a boric acid aqueous solution at 67 ° C. containing 2.35 parts of boric acid and 15 parts of potassium iodide per 100 parts of water for 30 seconds. Then, it was washed with pure water at 10 ° C. and dried at 80 ° C. to obtain a linear polarizing layer. The thickness of the obtained linear polarizing layer was 8 μm. Further, a protective layer was attached to one side of the obtained linear polarizing layer via an aqueous adhesive and dried at 90 ° C. to obtain a polarizing plate having a protective layer on one side of the linear polarizing layer. As the protective layer, a cycloolefin film with a hard coat layer having a thickness of 27 μm (hereinafter, may be referred to as “COP film with HC”) was used, and the cycloolefin film side of the COP film with HC was bonded to the linear polarizing layer. .. The obtained polarizing plate was a COP film with HC (protective layer), an adhesive layer (first bonded layer), and a linear polarizing layer laminated in this order. The moisture permeability of the COP film with HC was 8 g / m ^2/24 hr.

[Preparation of retardation layer]
(Preparation of 1/2 wavelength retardation layer)
A composition for forming an alignment layer was applied onto a substrate layer formed of a transparent resin and dried to perform a λ / 2 alignment treatment. Next, a composition for forming a liquid crystal layer containing a discotic polymerizable liquid crystal compound is applied onto the alignment layer, and the orientation of the substrate layer is fixed by heating and UV irradiation to fix the orientation of the polymerizable liquid crystal compound. A 1/2 wavelength retardation layer as a cured product layer having a thickness of 2 μm was formed on the layer.

(Preparation of λ / 4 wavelength retardation layer)
A liquid crystal layer forming composition containing a rod-shaped nematically polymerizable liquid crystal compound (liquid crystal monomer) was applied to the rubbing-treated alignment layer on the base material layer formed of the transparent resin to maintain the refractive anisotropy. By solidifying in the state, a 1/4 wavelength retardation layer as a cured product layer having a thickness of 1 μm was formed on the oriented layer of the base material layer.

(Preparation of retardation layer with base material layer)
Corona treatment was applied to the surface of the 1/2 wavelength retardation layer on the base material layer and the surface of the 1/4 wavelength retardation layer on the base material layer. The corona-treated surfaces were bonded to each other using the active energy ray-curable adhesive prepared above so that the angle formed by the slow axes of these two retardation layers was 60 °. After that, from the 1/4 wavelength retardation layer side, using an ultraviolet irradiation device [manufactured by Fusion UV Systems Co., Ltd.], ultraviolet irradiation is performed with an integrated light amount of 400 mJ / cm ² (UV-B) to perform active energy ray curing type adhesion. The agent was cured to form an adhesive layer as a bonding layer (bonding layer (X)). The bonding was performed using a laminator, and the active energy ray-curable adhesive was applied so that the thickness of the adhesive layer after curing was 3 μm. As a result, the base material layer, the alignment layer, the 1/2 wavelength retardation layer (first cured product layer), the adhesive layer (bonding layer, bonding layer (X)), and the 1/4 wavelength retardation layer (first). A retardation layer with a base material layer was obtained in which the 2 cured product layer), the alignment layer, and the base material layer were laminated in this order. Of the retardation layers with a substrate layer, a 1/2 wavelength retardation layer (first cured product layer), an adhesive layer (bonding layer, bonding layer (X)), and a 1/4 wavelength retardation layer. The layer (second cured product layer) formed a retardation layer in the optical laminates of Examples and Comparative Examples, and the thickness of this retardation layer was 6 μm.

(3) Preparation of Optical Laminate [Example 1]
The 1/2 wavelength retardation layer exposed by peeling off the base material layer and the alignment layer on the 1/2 wavelength retardation layer side of the retardation layer with the base material layer prepared above, and the straight line of the polarizing plate prepared above. The polarizing layer side was bonded to each other using an acrylic pressure-sensitive adhesive layer (storage elastic modulus: 125,000 Pa) having a thickness of 5 μm. The bonding of the 1/2 wavelength retardation layer and the polarizing plate was performed so that the angle formed by the slow axis of the 1/2 wavelength retardation layer and the transmission axis of the linear polarizing layer was 15 °. Next, an acrylic pressure-sensitive adhesive layer (storage elastic modulus: 125,000 Pa) having a thickness of 5 μm was applied to the 1/4 wavelength retardation layer exposed by peeling off the alignment layer on the 1/4 wavelength retardation layer side and the base material layer. A cycloolefin film (1) having a thickness of 13 μm (hereinafter, may be referred to as “COP film (1)”) as a barrier layer in which the surface in contact with the acrylic pressure-sensitive adhesive layer is subjected to corona treatment is laminated. , An adhesive layer (storage elastic modulus: 25,500 Pa) (hereinafter, may be referred to as “adhesive layer (a)”) having a thickness of 15 μm is formed on the surface of the COP film to form an optical laminate (1). Obtained.

The optical laminate (1) includes a COP film with HC (protective layer, first protective layer), an adhesive layer (first bonded layer), a linear polarizing layer, an adhesive layer (bonded layer (Y)), and 1 / 2 wavelength retardation layer (first cured product layer), adhesive layer (bonding layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer), adhesive layer (bonding layer) The laminated layer (Z)), the COP film (1) (barrier layer), and the pressure-sensitive adhesive layer (a) were laminated in this order. Distance D from the surface of the linear polarizing layer on the 1/2 wavelength retardation layer side to the surface of the pressure-sensitive adhesive layer (a) on the side opposite to the COP film side (adhesive layer (bonded layer (Y)) to adhesive The thickness of the agent layer (a)) was 44 μm.

The moisture permeability of the COP film (1) used for the optical laminate (1) was measured, the iodine content of the pressure-sensitive adhesive layer (a) in the optical laminate (1) was measured, and the corrosiveness of the metal layer was evaluated. rice field. The results are shown in Table 1.

[Example 2]
Same as Example 1 except that a cycloolefin film (2) having a thickness of 23 μm (hereinafter, may be referred to as “COP film (2)”) is used as the barrier layer instead of the COP film (1). The optical laminate (2) was obtained.

The optical laminate (2) includes a COP film with HC (protective layer, first protective layer), an adhesive layer (first bonded layer), a linear polarizing layer, an adhesive layer (bonded layer (Y)), and 1 / 2 wavelength retardation layer (first cured product layer), adhesive layer (bonding layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer), adhesive layer (bonding layer) The laminated layer (Z)), the COP film (2) (barrier layer), and the pressure-sensitive adhesive layer (a) were laminated in this order. Distance D from the surface of the linear polarizing layer on the 1/2 wavelength retardation layer side to the surface of the pressure-sensitive adhesive layer (a) on the side opposite to the COP film side (adhesive layer (bonded layer (Y)) to adhesive The thickness of the agent layer (a)) was 54 μm.

The moisture permeability of the COP film (2) used for the optical laminate (2) was measured, the iodine content of the pressure-sensitive adhesive layer (a) in the optical laminate (2) was measured, and the corrosiveness of the metal layer was evaluated. rice field. The results are shown in Table 1.

[Example 3]
The optical laminate (3) is the same as in Example 1 except that an acrylic film having a thickness of 20 μm (hereinafter, may be referred to as “PMMA film”) is used as the barrier layer instead of the COP film (1). ) Was obtained.

The optical laminate (3) includes a COP film with HC (protective layer, first protective layer), an adhesive layer (first bonded layer), a linear polarizing layer, an adhesive layer (bonded layer (Y)), and 1 / 2 wavelength retardation layer (first cured product layer), adhesive layer (bonding layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer), adhesive layer (bonding layer) The laminated layer (Z)), the PMMA film (barrier layer), and the pressure-sensitive adhesive layer (a) were laminated in this order. Distance D from the surface of the linear polarizing layer on the 1/2 wavelength retardation layer side to the surface of the pressure-sensitive adhesive layer (a) on the side opposite to the COP film side (adhesive layer (bonded layer (Y)) to adhesive The thickness of the agent layer (a)) was 51 μm.

The moisture permeability of the PMMA film used for the optical laminate (3) was measured, the iodine content of the pressure-sensitive adhesive layer (a) in the optical laminate (3) was measured, and the corrosiveness of the metal layer was evaluated. The results are shown in Table 1.

[Example 4]
The COP as a barrier layer is applied to the 1/4 wavelength retardation layer exposed by peeling off the alignment layer and the base material layer on the 1/4 wavelength retardation layer side by using the active energy ray-curable adhesive prepared above. An optical laminate (4) was obtained in the same manner as in Example 1 except that the film (1) was bonded and the active energy ray-curable adhesive was cured to form an adhesive layer having a thickness of 2 μm.

The optical laminate (4) includes a COP film with HC (protective layer, first protective layer), an adhesive layer (first bonded layer), a linear polarizing layer, an adhesive layer (bonded layer (Y)), and 1 / 2 wavelength retardation layer (first cured product layer), adhesive layer (bonding layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer), adhesive layer (bonding layer) The laminated layer (Z)), the COP film (1) (barrier layer), and the pressure-sensitive adhesive layer (a) were laminated in this order. Distance D from the surface of the linear polarizing layer on the 1/2 wavelength retardation layer side to the surface of the pressure-sensitive adhesive layer (a) on the side opposite to the COP film side (adhesive layer (bonded layer (Y)) to adhesive The thickness of the agent layer (a)) was 41 μm.

The iodine content of the pressure-sensitive adhesive layer (a) in the optical laminate (4) was measured, and the corrosiveness of the metal layer was evaluated. The results are shown in Table 1.

[Comparative Example 1]
The pressure-sensitive adhesive layer (a) is directly applied to the 1/4 wavelength retardation layer exposed by peeling off the alignment layer and the base material layer on the 1/4 wavelength retardation layer side without providing the acrylic pressure-sensitive adhesive layer and the barrier layer. An optical laminate (5) was obtained in the same manner as in Example 1 except that it was formed.

The optical laminate (5) includes a COP film with HC (protective layer, first protective layer), an adhesive layer (first bonded layer), a linear polarizing layer, an adhesive layer (bonded layer (Y)), and 1 / 2 wavelength retardation layer (first cured product layer), adhesive layer (bonding layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer), and adhesive layer ( a) was laminated in this order. Distance D from the surface of the linear polarizing layer on the 1/2 wavelength retardation layer side to the surface of the pressure-sensitive adhesive layer (a) on the side opposite to the COP film side (adhesive layer (bonded layer (Y)) to adhesive The thickness of the agent layer (a)) was 26 μm.

The iodine content of the pressure-sensitive adhesive layer (a) in the optical laminate (5) was measured, and the corrosiveness of the metal layer was evaluated. The results are shown in Table 1.

[Example 5]
The 1/2 wavelength retardation layer exposed by peeling off the base material layer and the alignment layer on the 1/2 wavelength retardation layer side and the linear polarizing layer side of the polarizing plate are bonded to the active energy ray-curable adhesive prepared above. An optical laminate (6) was obtained in the same manner as in Example 1 except that the adhesive was bonded using an agent and the active energy ray-curable adhesive was cured to form an adhesive layer having a thickness of 2 μm.

The optical laminate (6) includes a COP film with HC (protective layer, first protective layer), an adhesive layer (first bonded layer), a linear polarizing layer, an adhesive layer (bonded layer (Y)), and 1 / 2 wavelength retardation layer (first cured product layer), adhesive layer (bonding layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer), adhesive layer (bonding layer) The laminated layer (Z)), the COP film (1) (barrier layer), and the pressure-sensitive adhesive layer (a) were laminated in this order. Distance D from the surface of the linear polarizing layer on the 1/2 wavelength retardation layer side to the surface of the pressure-sensitive adhesive layer (a) on the side opposite to the COP film side (adhesive layer (bonded layer (Y)) to adhesive The thickness of the agent layer (a)) was 41 μm.

The iodine content of the pressure-sensitive adhesive layer (a) in the optical laminate (6) was measured, and the corrosiveness of the metal layer was evaluated. The results are shown in Table 1.

[Example 6]
The COP as a barrier layer is applied to the 1/4 wavelength retardation layer exposed by peeling off the alignment layer and the base material layer on the 1/4 wavelength retardation layer side by using the active energy ray-curable adhesive prepared above. An optical laminate (7) was obtained in the same manner as in Example 5 except that the film (1) was bonded and the active energy ray-curable adhesive was cured to form an adhesive layer having a thickness of 2 μm.

The optical laminate (7) includes a COP film with HC (protective layer, first protective layer), an adhesive layer (first bonded layer), a linear polarizing layer, an adhesive layer (bonded layer (Y)), and 1 / 2 wavelength retardation layer (first cured product layer), adhesive layer (bonding layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer), adhesive layer (bonding layer) The laminated layer (Z)), the COP film (1) (barrier layer), and the pressure-sensitive adhesive layer (a) were laminated in this order. Distance D from the surface of the linear polarizing layer on the 1/2 wavelength retardation layer side to the surface of the pressure-sensitive adhesive layer (a) on the side opposite to the COP film side (adhesive layer (bonded layer (Y)) to adhesive The thickness of the agent layer (a)) was 38 μm.

The iodine content of the pressure-sensitive adhesive layer (a) in the optical laminate (7) was measured, and the corrosiveness of the metal layer was evaluated. The results are shown in Table 1.

[Example 7]
An optical laminate (8) was obtained in the same manner as in Example 6 except that a triacetyl cellulose film having a thickness of 20 μm (hereinafter, may be referred to as “TAC film”) was used as the barrier layer.

The optical laminate (8) includes a COP film with HC (protective layer, first protective layer), an adhesive layer (first bonded layer), a linear polarizing layer, an adhesive layer (bonded layer (Y)), and 1 / 2 wavelength retardation layer (first cured product layer), adhesive layer (bonding layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer), adhesive layer (bonding layer) The laminated layer (Z)), the TAC film (barrier layer), and the pressure-sensitive adhesive layer (a) were laminated in this order. Distance D from the surface of the linear polarizing layer on the 1/2 wavelength retardation layer side to the surface of the pressure-sensitive adhesive layer (a) on the side opposite to the COP film side (adhesive layer (bonded layer (Y)) to adhesive The thickness of the agent layer (a)) was 45 μm.

The moisture permeability of the TAC film used in the optical laminate (8) was measured, the iodine content of the pressure-sensitive adhesive layer (a) in the optical laminate (8) was measured, and the corrosiveness of the metal layer was evaluated. The results are shown in Table 1.

[Comparative Example 2]
The pressure-sensitive adhesive layer (a) is directly applied to the 1/4 wavelength retardation layer exposed by peeling off the alignment layer and the base material layer on the 1/4 wavelength retardation layer side without providing the acrylic pressure-sensitive adhesive layer and the barrier layer. An optical laminate (9) was obtained in the same manner as in Example 5 except that it was formed.

The optical laminate (9) includes a COP film with HC (protective layer, first protective layer), an adhesive layer (first bonded layer), a linear polarizing layer, an adhesive layer (bonded layer (Y)), and 1 / 2 wavelength retardation layer (first cured product layer), adhesive layer (bonding layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer), and adhesive layer ( a) was laminated in this order. Distance D from the surface of the linear polarizing layer on the 1/2 wavelength retardation layer side to the surface of the pressure-sensitive adhesive layer (a) on the side opposite to the COP film side (adhesive layer (bonded layer (Y)) to adhesive The thickness of the agent layer (a)) was 23 μm.

The iodine content of the pressure-sensitive adhesive layer (a) in the optical laminate (9) was measured, and the corrosiveness of the metal layer was evaluated. The results are shown in Table 1.

1,1a, 1b, 1c, 1d, 1e, 1f Optical laminate, 4 barrier layer, 5 adhesive layer, 6 metal layer, 10 retardation layer, 11 first cured product layer (cured product layer), 12 second Hardened material layer (cured material layer), 21 1st bonded layer, 22 2nd bonded layer, 23 bonded layer (Y), 24 bonded layer (Z), 25 bonded layer (X), 30 polarizing plate , 31 Linearly polarizing layer, 32 First protective layer (protective layer), 33 Second protective layer (protective layer).

Claims (10)

An optical laminate including a linearly polarized light layer, a retardation layer, a barrier layer, and an adhesive layer in this order.
The linear polarizing layer is a polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented.
The retardation layer contains at least one cured product layer obtained by polymerizing and curing the polymerizable liquid crystal compound.
The barrier layer is provided in direct contact with the pressure-sensitive adhesive layer.
The moisture permeability of the barrier layer at a temperature of 40 ° C. and a relative humidity of 90% RH is 1 g / m ^2/24 hr or more and 2000 g / m ^2/24 hr or less.
An optical laminate having a distance from the surface of the linear polarizing layer on the retardation layer side to the surface of the pressure-sensitive adhesive layer on the side opposite to the barrier layer side of 55 μm or less. The optical laminate according to claim 1, wherein the amount of iodine in the pressure-sensitive adhesive layer after the optical laminate is stored at a temperature of 85 ° C. and a relative humidity of 85% RH for 240 hours is 250 ppm or less. The optical laminate according to claim 1 or 2, wherein the barrier layer is a resin film. The retardation layer is
It contains two layers of the cured product and contains two layers.
The optical laminate according to any one of claims 1 to 3, further comprising a bonding layer (X) for bonding the two cured product layers to each other. The optical laminate according to claim 4, wherein the bonded layer (X) is an adhesive layer. Further, the polarizing plate including the linear polarizing layer and the bonding layer (Y) for bonding the polarizing plate and the retardation layer are included.
The optical laminate according to any one of claims 1 to 5, wherein the polarizing plate is provided with a protective layer on one side or both sides of the linear polarizing layer. The optical laminate according to any one of claims 1 to 6, further comprising a bonding layer (Z) for bonding the retardation layer and the barrier layer. The optical laminate according to claim 7, wherein the bonded layer (Z) is an adhesive layer. The optical laminate according to any one of claims 1 to 8, further comprising a metal layer on the side of the pressure-sensitive adhesive layer opposite to the barrier layer side. The optical laminate according to claim 9, wherein the metal layer is provided in direct contact with the pressure-sensitive adhesive layer.

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