TW202222573A - Optical laminate - Google Patents

Abstract

A subject of the present invention is providing an optical laminate that can suppress corrosion of metal layer in high temperature and high humidity environment.

A means for attaining the above-mentioned subject is an optical laminate, which includes a linearly polarizing layer, a phase difference layer, a barrier layer, and a pressure-sensitive adhesive layer in this order. The linearly polarizing layer is a polyvinyl alcohol resin film with iodine adsorbed and aligned therein. The phase difference layer includes at least one hardened layer formed by polymerizing and hardening a polymerizable liquid crystal compound. The barrier layer is such provided to directly contact the adhesive layer. The moisture permeability of the barrier layer at a temperature of 40℃ and a relative humidity of 90% RH is 1g/m²/24hr or more and 2000g/m²/24hr or less. The distance from a surface of the linearly polarizing layer on the side of the phase difference layer to a surface of the adhesive layer on the side opposite to the barrier layer is 55 μm or less.

Description

Optical laminate

The present invention relates to an optical laminate.

Polarizing plates are used as one of optical elements constituting display devices such as liquid crystal display devices and organic EL display devices. The polarizing plate usually has a laminated structure in which a protective layer is layered on one side or two areas of the linear polarizing layer, and is assembled in a display device with the laminated structure. In addition, in display devices of the touch panel type mainly used in mobile information terminals such as smartphones and tablet computers, it is known that a touch sensor is provided between a polarizing plate and an image display element to constitute a touch sensor. the conductive layer (for example, Patent Documents 1 to 3, etc.).

In recent years, in order to improve the designability of the display device, the entire display device is required to be thinned. In addition, when a display device such as a flexible display is folded or rolled, if the thickness of the display device is smaller, the stress caused by the folding and winding can be reduced, and the occurrence of defects can be suppressed. Therefore, various components used in the display device are required to be thinned and the number of components used can be reduced by functional integration.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-52765

[Patent Document 2] Japanese Patent Laid-Open No. 2015-172740

[Patent Document 3] International Publication No. 2020/111232

It is found that when a metal layer is used as a conductive layer for forming a touch sensor, when the distance between the linear polarizing layer and the metal layer becomes closer with the thinning of the display device, the metal layer tends to corrode in a high temperature and high humidity environment .

It is an object of the present invention to provide an optical laminate which can suppress exposure to a high temperature and high humidity environment even when the display device is thinned by thinning and/or reducing various members used in the display device. Corrosion of the metal layer.

The present invention provides the following optical laminate.

[1] An optical laminate, comprising a linear polarizing layer, a retardation layer, a barrier layer and an adhesive (pressure-sensitive adhesive, also known as pressure-sensitive adhesive) layer in sequence; wherein,

The aforementioned linear polarizing layer is a polyvinyl alcohol-based resin film with iodine adsorbed and aligned,

The retardation layer includes at least one cured product layer formed by polymerizing and curing a polymerizable liquid crystal compound,

The above-mentioned barrier layer is arranged in direct contact with the above-mentioned adhesive layer,

The moisture permeability of the aforementioned barrier layer at a temperature of 40°C and a relative humidity of 90% RH is 1g/m ² /24hr or more and 2000g/m ² /24hr or less,

The distance from the surface on the retardation layer side of the linearly polarizing layer to the surface on the opposite side to the barrier layer side of the adhesive layer is 55 μm or less.

[2] The optical layered product according to [1], wherein the iodine content of the adhesive layer is 250 ppm or less after the optical layered product is stored for 240 hours under conditions of a temperature of 85° C. and a relative humidity of 85% RH.

[3] The optical laminate according to [1] or [2], wherein the barrier layer is a resin film.

[4] The optical laminate according to any one of [1] to [3], wherein the retardation layer includes two layers of the cured product layer,

And the said retardation layer contains the bonding layer (X) for bonding the said two hardened|cured material layers mutually.

[5] The optical laminate according to [4], wherein the bonding layer is an adhesive layer.

[6] The optical laminate according to any one of [1] to [5], further comprising: a polarizing plate containing the linear polarizing layer, and a sticker for bonding the polarizing plate and the retardation layer together Laminate (Y),

In the aforementioned polarizing plate, a protective layer is provided on one side or both sides of the aforementioned 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 bonding 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 opposite to the barrier layer side of the adhesive layer.

[10] The optical laminate according to [7], wherein the metal layer is provided in direct contact with the 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 thinned by thinning and/or reducing various members used in the display device.

1, 1a, 1b, 1c, 1d, 1e, 1f: Optical laminates

4: Barrier layer

5: Adhesive layer

6: Metal layer

10: retardation layer

11: The first hardened material layer (hardened material layer)

12: Second hardened material layer (hardened material layer)

21: The first bonding layer

22: The second bonding layer

23: Lamination layer (Y)

24: Lamination layer (Z)

25: Lamination layer (X)

30: polarizer

31: Linear polarizing layer

32: The first protective layer (protective layer)

33: Second protective layer (protective layer)

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

FIG. 2 is a schematic cross-sectional view schematically showing another example of the optical laminate of the present invention.

FIG. 3 is a schematic cross-sectional view schematically showing yet another example of the optical laminate of the present invention.

FIG. 4 is a schematic cross-sectional view schematically showing yet another example of the optical laminate of the present invention.

5 is a schematic cross-sectional view schematically showing yet another example of the optical laminate of the present invention.

6 is a schematic cross-sectional view schematically showing yet another example of the optical laminate of the present 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 the drawings below are shown to facilitate understanding of the present invention, and the dimensions and shapes of the components shown in the drawings do not necessarily correspond to the dimensions and shapes of the actual components.

(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 laminates 1") include a linearly polarizing layer 31, a retardation layer 10, a barrier layer 4, and an adhesive layer 5 in this order. The linearly polarizing layer 31 is a polyvinyl alcohol-based resin film (hereinafter sometimes referred to as "PVA-based film") in which iodine is adsorbed and aligned. The retardation layer 10 includes at least one cured product layer (the first cured product layer 11, the second cured product layer 12, and the like described later) formed by polymerizing and curing a polymerizable liquid crystal compound. The barrier layer 4 is provided in direct contact with the 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 /24hr or more and 2000 g/m ² /24hr or less. In the optical layered body 1, the distance D from the surface of the linear polarizing layer 31 on the retardation layer 10 side to the surface of the adhesive layer 5 on the opposite side from the barrier layer 4 side is 55 μm or less.

The optical layered body 1 may further include the metal layer 6 on the opposite side of the adhesive layer 5 from the side of the barrier layer 4 as in the optical layered bodies 1e and 1f shown in FIGS. 5 and 6 . The metal layer 6 is preferably disposed in direct contact with the adhesive layer 5 .

In the optical laminate 1 having the above-mentioned layer structure, when the optical laminates 1a to 1d are laminated on the metal layer 6 through the adhesive layer 5, or in the optical laminates 1e, 1f, the occurrence of the metal layer 6 can be suppressed. corrosion, especially pitting corrosion of the metal layer 6. The reason why the corrosion of the metal layer 6 can be suppressed by the optical layered body 1 is presumed as follows. As a PVA film with iodine in the adsorption alignment of the linear polarizing layer, a small amount of iodine oozes out from the PVA film in a high temperature and high humidity environment. In a laminate including a linearly polarizing layer and a metal layer, when iodine oozing out from the linearly polarizing layer reaches the metal layer, it is believed to corrode the metal layer. Here, in the optical layered body 1 , the barrier layer 4 having the moisture permeability in the above-mentioned range is provided so as to be in contact with the adhesive layer 5 for bonding to the metal layer 6 . Accordingly, even in the thin optical layered body 1 with a distance D of 55 μm or less, the iodine exuded from the linear polarizing layer 31 can be suppressed from reaching the metal layer 6 and corrosion of the metal layer 6 can be suppressed.

As shown in FIGS. 1 to 6 , the optical laminate 1 may include a polarizing plate 30 having protective layers 32 and 33 on one side or both sides of the linear polarizing layer 31 (hereinafter sometimes referred to as “the first 1 protective layer 32" and "second protective layer 33"). From the viewpoint of reducing the thickness of the optical layered body 1 , the polarizing plate 30 preferably has the first protective layer 32 or the second protective layer 33 only on one side of the linearly polarizing layer 31 . When there is a protective layer on only one side of the linear polarizing layer 31, from the viewpoint of protecting the linear polarizing layer 31, it is preferable to be as shown in FIG. 1 and FIG. 2 . As shown, the linear polarizing layer 31 has the first protective layer 32 on the opposite side to the retardation layer 10 side. Since the optical layered body 1 has the barrier layer 4, even when the first protective layer 32 is provided and the second protective layer 33 is not provided, the corrosion of the metal layer 6 can be effectively suppressed. For example, as shown in FIGS. 1 to 6 , the first protective layer 32 and/or the second protective layer 33 may be disposed on the linear polarizing layer 31 through the first bonding layer 21 and/or the second bonding layer 22 . The first bonding layer 21 and the second bonding layer 22 are adhesive layers or adhesive layers.

The optical layered body 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 together. At this time, for example, as shown in FIGS. 1 to 6 , the retardation layer 10 is provided on the linear polarizing layer 31 or the polarizing plate 30 through the bonding layer (Y) 23 . The bonding layer (Y) 23 is an adhesive layer or an adhesive layer. Alternatively, the retardation layer 10 may also be disposed in direct contact with the linear polarizing layer 31 or the polarizing plate 30 .

The optical layered body 1 may further include a bonding layer (Z) 24 for bonding the retardation layer 10 and the barrier layer 4 together. At this time, for example, as shown in FIGS. 1 to 6 , the barrier layer 4 may be provided on the retardation layer 10 through the bonding layer (Z) 24 . The bonding layer (Z) 24 is an adhesive layer or an adhesive layer. Alternatively, the barrier layer 4 may be disposed in direct contact with the retardation layer 10 . When the optical layered body 1 includes the bonding layer (Z) 24, the bonding layer (Z) 24 is preferably an adhesive layer. Thereby, when the optical layered body 1 is cut with a cutting blade, for example, deformation of the retardation layer 10 can be suppressed on the cut surface.

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

The amount of iodine in the adhesive layer is preferably 250 ppm or less, more preferably 200 ppm or less, and more preferably 150 ppm or less, after the optical layered body 1 is stored for 240 hours under the conditions of a temperature of 85° C. and a relative humidity of 85% RH. More preferably, it is 100 ppm or less, and may be 50 ppm or less, 30 ppm or less, or 10 ppm or less. By making the said amount of iodine within the above-mentioned range, it is easy to suppress when the optical layered body 1 is exposed. Corrosion of the metal layer 6 in a high temperature and high humidity environment. The amount of iodine can be adjusted, for example, by the following methods: adjusting the moisture permeability of the barrier layer 4; disposing the first protective layer 32 and/or the second protective layer 33 on the linear polarizing layer 31; adjusting the first protective layer 32 and/or the type, thickness, etc. of the second protective layer 33 . The said iodine amount can be measured by the method described in the Example mentioned later.

In the optical layered bodies 1 a to 1 d shown in FIGS. 1 to 4 , a release film may be provided on the opposite side of the adhesive layer 5 from the retardation layer 10 side. The release film covers the adhesive layer 5 for protection or supports the adhesive layer 5 , and has a function as a separation film that can peel the adhesive layer 5 . Examples of the release film include those obtained by applying a release treatment such as a silicone treatment to the surface of the base film on the adhesive layer side. As a resin material which comprises a base film, the resin material which comprises a protective layer mentioned later is mentioned. The resin film may have a single-layer structure, or may be a multilayer resin film having a multilayer structure of two or more layers.

The optical laminates 1 a to 1 d shown in FIGS. 1 to 4 can constitute 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 layered bodies 1a to 1d are circularly polarizing plates, at least one layer of the cured product layer 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 can be respectively [ i] 1/2 wavelength retardation layer and 1/4 wavelength retardation layer, [ii] 1/4 wavelength retardation layer and positive type C plate, or [iii] positive type C plate and 1/4 wavelength retardation layer . The λ/4 wavelength retardation layer may have reverse wavelength dispersion.

The optical laminate 1 can be used in display devices such as smart phones and tablet computers, and is especially suitable for use in display devices of a touch panel type. As a display device, an organic EL display device, a liquid crystal display device, etc. are mentioned. The display device may be a flexible display.

The details of each member used in the optical layered body 1 will be described below.

(linear polarizing layer)

The linearly polarizing layer has the 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 film with iodine adsorbed and aligned.

Examples of the linear polarizing layer include applying dyeing treatment with iodine and stretching to PVA-based films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene/vinyl acetate copolymer-based partially saponified films. processed, etc. If necessary, the PVA-based film with iodine adsorbed and aligned by dyeing treatment may be treated with a boric acid aqueous solution, and then a washing step of washing away the boric acid aqueous solution may be performed. A well-known method can be used for each step.

A polyvinyl alcohol-based resin (hereinafter sometimes referred to as "PVA-based resin") can be produced by saponifying a polyvinyl acetate-based resin. In addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, the polyvinyl acetate-based resin may also be a copolymer of vinyl acetate and other monomers that can be copolymerized with vinyl acetate. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamides having an ammonium group, and the like.

The degree of saponification of the PVA-based resin is usually about 85 to 100 mol %, preferably 98 mol % or more. PVA-based resins can be modified, and for example, aldehyde-modified polyvinyl formal, polyvinyl acetal, and the like 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). When the average degree of polymerization is less than 1,000, it is difficult to obtain better polarization performance, and when it exceeds 10,000, the film processability may deteriorate.

The method for producing a linearly polarizing layer comprising a PVA-based film may include the steps of preparing a base film, coating a solution of a resin such as a PVA-based resin on the base film, and drying the base film to remove the solvent. A resin layer is formed on the material film. In addition, an undercoat layer may be formed in advance on the surface of the base film on which the resin layer is to be formed. As the base film, a resin film such as PET can be used, or a thermoplastic that can be used for the protective layer described later can be used. resin film. As the material of the undercoat layer, the hydrophilic resin used for the linear polarizing layer is cross-linked, and the like is mentioned.

Next, after adjusting the amount of solvent such as moisture in the resin layer as necessary, the base film and the resin layer are uniaxially stretched, and the resin layer is then dyed with iodine to adsorb and align the iodine on the resin layer. Next, if necessary, the resin layer with iodine adsorbed and aligned is treated with a boric acid aqueous solution, and then a cleaning step of rinsing the boric acid aqueous solution is performed. Thereby, the film of the resin layer in which iodine is adsorbed and aligned, that is, a linear polarizing layer is produced. A known method can be employed in each step.

The amount of boric acid in the boric acid-containing aqueous solution for treating the iodine-adsorbed PVA-based film or resin layer is usually about 2 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water . 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 uniaxial stretching of the PVA-based film, the base film, and the resin layer can be performed before dyeing, during dyeing, during boric acid treatment after dyeing, or uniaxially stretched in each of these plural stages. The PVA-based film, the base film, and the resin layer can be uniaxially stretched in the MD direction (film conveying direction). to extend. In addition, the PVA-based film, the base film, and the resin layer can be uniaxially stretched in the TD direction (direction perpendicular to the film conveying direction), and in this case, a so-called tenter method can be used. In addition, the above-mentioned stretching may be dry stretching in which the stretching is performed in the atmosphere, or wet stretching in which the PVA-based film or the resin layer is stretched in a state of being swollen in a solvent. When the performance of the linear polarizing layer is to be exhibited, the stretching magnification is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times. times more. There is no particular upper limit of the stretching ratio, but it is preferably 8 times or less from the viewpoint of suppressing breakage and the like.

The linearly polarizing layer produced by the manufacturing method of a base film can be obtained by peeling a base film after laminating|stacking the protective layer mentioned later. By this method, the linearly polarizing layer can be further thinned.

The thickness of the linear polarizing layer is preferably 1 μm or more, also can be 2 μm or more, or 5 μm or more, and preferably 30 μm or less, more preferably 15 μm or less, and more preferably 10 μm m or less, or 8 μm or less. The smaller the thickness of the linear polarizing layer, the easier it is to seep out iodine in a high temperature and high humidity environment. Therefore, when the thickness of the linearly polarizing layer is small, by setting it as the optical layered body 1 of the present embodiment, corrosion of the metal layer 6 can be effectively suppressed.

In the cleaning step of treating the iodine-adsorbed PVA film or resin layer with a boric acid aqueous solution and then rinsing the boric acid aqueous solution, the lower the boric acid concentration in the boric acid aqueous solution, the easier it is to seep out iodine in a high temperature and high humidity environment . Therefore, when the boric acid concentration in the boric acid aqueous solution used in the production step of the linear polarizing layer is low, the corrosion of the metal layer 6 can be effectively suppressed by setting it as the optical layered body 1 of the present embodiment. .

(Polarizer)

As shown in FIGS. 1 to 6 , the polarizing plate 30 may be formed on a single-sided or double-sided protective layer (the first protective layer 32 and/or the second protective layer 33 ) on the linear polarizing layer 31 . The polarizing plate 30 is a so-called linear polarizing plate. The first protective layer 32 and/or the second protective layer 33 that can be laminated on one side or both sides of the linear polarizing layer 31 can be used, for example, by transparency, mechanical strength, thermal stability, moisture barrier, isotropy, A film formed of a thermoplastic resin excellent in elongation and the like. Specific examples of thermoplastic resins include: cellulose resins such as cellulose triacetate; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether resins; polyresins; polycarbonates Ester resins; polyamide resins such as nylon and aromatic polyamide; polyimide resins; polyolefin resins such as polyethylene, polypropylene, and ethylene/propylene copolymers; Olefin resins (also called norbornene-based resins); (meth)acrylic resins; polyarylate resins; polystyrene resins; polyvinyl alcohol resins, and mixtures of these. The resin compositions 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 acid" means that either acrylic acid or methacrylic acid may be used. The "(meth)" of (meth)acrylate etc. also 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 layered body 1 of the present embodiment, when the above-mentioned water vapor transmission rate of the first protective layer 32 is 300 g/m ² /24hr or less, corrosion of the metal layer can be effectively suppressed, and the above-mentioned water vapor transmission rate of the first protective layer 32 is: When it is 100 g/m ² /24hr or less, the corrosion of the metal layer can be further effectively suppressed. When the above-mentioned moisture permeability of the first protective layer 32 decreases, iodine in the linearly polarizing layer 31 in the optical layered body 1 does not easily move to the first protective layer 32 side, but tends to move to the adhesive layer 5 side. Since the optical layered body 1 has the barrier layer 4, even if the iodine easily migrates to the side of the adhesive layer 5 as described above, the metal layer 6 provided on the opposite side of the adhesive layer 5 from the side of the barrier layer 4 can be suppressed from being corroded situation. The above-mentioned moisture permeability of the first protective layer 32 and the second protective layer 33 can be measured by a moisture permeability test method (moisture permeability cup method, JIS Z 0208).

The first protective layer 32 and the second protective layer 33 may be those having retardation properties, or may be optical functional layers having functional properties such as a hard coat layer and an antireflection layer. The thicknesses of the first protective layer 32 and the second protective layer 33 are independently preferably 3 μm or more, more preferably 5 μm or more, and preferably 50 μm or less, more preferably 30 μm or less.

Preferably, the first protective layer 32 and the second protective layer 33 are bonded to the linear polarizing layer through the first bonding layer 21 and the second bonding layer 22 respectively ( FIGS. 1 to 6 ). The first bonding layer 21 and the second bonding layer 22 are connected Adhesive layer or adhesive layer. For 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 using a water-based adhesive to be described later.

(retardation layer)

The retardation layer 10 includes a layer having retardation characteristics. Examples of the layer having retardation properties include a cured product layer obtained by polymerization and curing of 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 including two or more cured material layers, the retardation layer 10 may include a bonding layer for bonding the cured material layers to each other (for example, the bonding layer (X) 25 shown in FIG. 2 , FIG. 4 , and FIG. 6 ) ). The hardened material layer may be a 1/2 wavelength retardation layer, a 1/4 wavelength retardation layer, or a positive type C plate. The 1/4 wavelength retardation layer may have reverse wavelength dispersion. When the retardation layer includes two or more cured product layers, the cured product layers may have mutually the same retardation characteristics or may have mutually different retardation characteristics.

The polymerizable liquid crystal compound includes a rod-shaped polymerizable liquid crystal compound and a disc-shaped polymerizable liquid crystal compound, and one of these may be used, or a mixture containing both may be used. When the rod-shaped polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the base material layer, the optical axis of the polymerizable liquid crystal compound is aligned with the long axis direction of the polymerizable liquid crystal compound. When aligning a discotic polymerizable liquid crystal compound, the optical axis of the polymerizable liquid crystal compound exists in a direction orthogonal to the disc plane 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, etc.) can be suitably used. As the discotic polymerizable liquid crystal compound, JP 2007-108732 A (paragraphs [0020] to [0067] etc.) and JP 2010-244038 A (paragraphs [0013] to [0108] etc.) can be suitably used recorder.

In order to express the in-plane retardation in the cured product layer formed by polymerizing the polymerizable liquid crystal compound, the polymerizable liquid crystal compound may be aligned in an appropriate direction. When the polymerizable liquid crystal compound is rod-shaped, the optical axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the plane of the substrate layer. The in-plane retardation is visualized, and at this time, the optical axis direction and the slow axis direction coincide. When the polymerizable liquid crystal compound has a disc shape, the optical axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the plane of the base material layer to express in-plane retardation, and at this time, the optical axis and the slow axis are orthogonal. The alignment 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 types of polymerizable liquid crystal compounds are used in combination, at least one type preferably has two or more polymerizable groups in the molecule. The polymerizable group means a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in a polymerization reaction by an active radical, an acid, or the like generated by a photopolymerization initiator described later. Examples of the polymerizable group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloxy, methacryloyloxy, and oxiranyl. , oxetanyl, styryl, allyl, etc. Among them, an acryloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloxy group is more preferable. The liquid crystallinity possessed by the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, and if the thermotropic liquid crystal is classified by orderliness, 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 alignment regulation force to align the polymerizable liquid crystal compound in a desired direction. The alignment layer can be a vertical alignment layer that aligns the molecular axis of the polymerizable liquid crystal compound vertically with respect to the base material layer, or a horizontal alignment layer that aligns the molecular axis of the polymerizable liquid crystal compound horizontally with respect to the base material layer. It may be an oblique alignment layer that aligns the molecular axis of the polymerizable liquid crystal compound obliquely 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 preferably has solvent resistance that does not dissolve by applying a liquid crystal layer-forming composition containing a polymerizable liquid crystal compound or the like, and has heat resistance to heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound. The alignment layer includes an alignment polymer layer formed of an alignment polymer, a photoalignment polymer layer formed of a photo-alignment polymer, and a groove alignment layer having a concavo-convex pattern or a plurality of grooves on the surface of the layer. .

The thickness of the cured product layer may be 0.1 μm or more, 0.5 μm or more, 1 μm or more, or 2 μm or more, and preferably 10 μm or less, and 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 the composition for forming a liquid crystal layer containing the polymerizable liquid crystal compound on the base material layer, drying the composition, and polymerizing the polymerizable liquid crystal compound. The composition for liquid crystal layer formation can also be apply|coated to 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 for example, a film using the resin material described above as the thermoplastic resin for forming the protective layer can be used. The thickness of the base material layer is not particularly limited, but generally, from the viewpoint of workability such as strength and handleability, it is preferably 1 to 300 μm , more preferably 20 to 200 μm , and still more preferably 30 to 120 μm . The base material layer may be assembled in the optical laminate together with the cured product layer of the polymerizable liquid crystal compound, or the base material layer may be peeled off, and only the cured product layer of the polymerizable liquid crystal compound, or the cured product layer and the alignment layer may be assembled in the optical laminate. Optical laminate. When the base material layer and the cured product layer of the polymerizable liquid crystal compound are assembled in the optical layered body 1, 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 , or may include the first cured product layer 11 and the second cured product as shown in FIGS. 2 , 4 and 6 . The layer 12 may include, in addition to the first cured product layer 11 and the second cured product layer 12, a bonding layer (X) 25 for bonding these.

Like the bonding layer (X) 25 , the bonding layer for bonding two or more cured product layers is an 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 curing adhesive, and more preferably an adhesive layer obtained by curing an ultraviolet curing adhesive. By using the bonding layer (X) 25 as an adhesive layer, when the optical layered body 1 is bent, folded, or wound, it is possible to suppress the occurrence of wrinkles in the cured product layer, which is preferable.

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

Although the thickness of the retardation layer 10 depends on the total number of hardened material layers contained in the retardation layer 10, it is usually 0.5 μm or more, and may be 1 μm or more, 2 μm or more, or 5 μm or more, Furthermore, it is preferably 50 μm or less, and may be 30 μm or less, 15 μm or less, or 10 μm or less.

(barrier layer)

In the optical layered body 1 , the barrier layer 4 may be provided in order to suppress the migration of iodine in the linearly polarizing layer 31 to the 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 1g/m ² /24hr or more, and can also be 30g/m ² /24hr or more, 100g/m ² /24hr or more, 200g/m ² / 24hr or more or 500g/m ² /24hr or more. The above-mentioned moisture permeability of the barrier layer is 2000 g/m ² /24hr or less, and may be 1500 g/m ² /24hr or less, 1200 g/m ² /24hr or less, or 1000 g/m ² /24hr or less. When the above-mentioned moisture permeability of the barrier layer 4 is less than 1 g/m ² /24hr, the optical deterioration of the linear polarizing layer 31 tends to become obvious in a high temperature and high humidity environment, and when it exceeds 2000 g/m ² /24hr, it may be difficult The tendency of corrosion of the metal layer 6 is suppressed. The said water vapor transmission rate can be measured by the water vapor transmission test method (moisture-permeable cup method, JIS Z 0208) as described in the Example mentioned 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 formed 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. As a resin film, the film which used the resin material demonstrated as the thermoplastic resin for forming a protective layer mentioned above is mentioned, for example. The resin film is preferably a cellulose resin film such as cellulose triacetate; a cyclic polyolefin resin (also referred to as a norbornene-based resin) film having a cyclic and norbornene structure; and a (meth)acrylic resin film.

The resin film may have retardation properties such as λ/4 retardation properties, but preferably does not have retardation properties (zero retardation properties). By making the resin film not have retardation characteristics, influence on the optical characteristics of the optical layered body 1 can be suppressed.

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, or 8 μm or more, and preferably 25 μm or less, more preferably 15 μm or less. When the thickness of the resin film becomes too large, when the optical layered body 1 is folded, there is a possibility that an influence such as a decrease in optical properties will occur.

When the barrier layer 4 is a resin film, the retardation layer 10 and the barrier layer 4 are preferably bonded together via 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, compared with the case where the bonding layer (Z) 24 is provided with an adhesive layer, even if the thickness is small, the retardation layer 10 and the barrier layer 4 can be sufficiently bonded. Force fit, and can reduce the distance D, so it is better.

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. The metal atoms contained in the inorganic material include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), sodium (Na), boron (B), lead (Pb), Zirconium (Zr), Yttrium (Y) and 2 of these atoms more than one species. The inorganic material may further contain hydrogen atoms (H), phosphorus atoms (P), sulfur atoms (S), fluorine atoms (F), chlorine atoms (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. The chemical vapor deposition method includes plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition using glow discharge plasma or the like. As the physical vapor deposition method, a vacuum vapor deposition method, a sputtering method, an ion plating method, an ionization cluster beam method, or the like can be mentioned.

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

In the optical layered body 1 , the inorganic layer may be directly formed on the surface of the retardation layer 10 , or the inorganic layer may be formed on the base film, and the retardation layer 10 may be bonded to the inorganic layer. As the base film, a film using the above-mentioned thermoplastic resin which can be used for the protective layer can be used.

When the barrier layer 4 is a resin cured layer, the resin cured layer can be formed by curing an active energy ray-curable resin. The resin hardening layer may be an overcoat layer obtained by coating the surface of the retardation layer 10 with an active energy ray curable resin and then hardening it. 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 active energy ray-curable adhesives for forming an adhesive layer described later.

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

The barrier layer 4 is preferably a resin film. It is recognized that the resin film can suppress the generation of cracks compared to the inorganic layer when the optical layered body 1 is cut into a desired size or when the optical layered body 1 is subjected to processing such as end surface processing. In addition, in the resin cured layer, in order to realize the above-mentioned moisture permeability, it may be necessary to apply the active energy ray curable resin to a thick layer. There is a possibility that the optical layered body 1 may be wrinkled or warped due to the generated curing heat. On the other hand, it is considered that the resin film can suppress the occurrence of the above-mentioned wrinkles and warpage compared to the resin cured layer.

(adhesive layer)

The adhesive layer 5 is a layer formed using an adhesive. The adhesive is called a so-called pressure-sensitive adhesive because it exhibits adhesiveness by sticking itself to an adherend such as a metal layer. In addition, the degree of crosslinking and the adhesive force of the active energy ray-curable adhesive described later can be adjusted by irradiating energy rays.

The thickness of the 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 adhesive layer 5 arranged near the metal layer 6 is small, the iodine concentration of the adhesive layer 5 is likely to increase compared to a laminate without the barrier layer 4 . Therefore, by setting it as the optical laminated body 1 like this embodiment, the corrosion which generate|occur|produces in the metal layer 6 can be suppressed effectively.

As the adhesive, conventionally known adhesives excellent in optical transparency can be used without particular limitation, for example, acrylic, urethane, polysiloxane, polyvinyl ether, etc. can be used. adhesive for the matrix polymer. Moreover, an active energy ray hardening type adhesive agent, a thermosetting type adhesive agent, etc. may be sufficient. Among these, an acrylic resin excellent in transparency, adhesive force, releasability (hereinafter also referred to as reworkability), weather resistance, heat resistance, etc. is suitable as the adhesive of the matrix polymer. The adhesive layer is preferably composed of a reaction product of an adhesive containing a (meth)acrylic resin, a crosslinking agent, and a silane compound, and may contain other components.

The adhesive layer 5 can be formed using an active energy ray-curable adhesive. Active energy ray-curable adhesives can be formed by mixing ultraviolet curable compounds such as multifunctional acrylates in the above-mentioned adhesives to form an adhesive layer, and then irradiating it with ultraviolet rays to harden it to form a harder adhesive. Floor. Active energy ray-curable adhesives are cured by irradiation with energy rays such as ultraviolet rays and electron beams. nature. Since the active energy ray-curable adhesive also has adhesiveness before irradiating the energy ray, the adhesive has the property of being able to adhere to the adherend such as a metal layer, and being hardened by the energy ray irradiation to adjust the adhesive force .

Generally, an active energy ray-curable adhesive contains an acrylic adhesive and an energy ray polymerizable compound as main components. Usually, a crosslinking agent is further blended, and if necessary, a photopolymerization initiator, a photosensitizer, and the like can also be blended.

The storage elastic modulus of the adhesive layer 5 can be, for example, 50,000 Pa or less, 49,000 Pa or less, or 40,000 Pa or less, and preferably 10,000 Pa or more. When the storage elastic modulus of the adhesive layer 5 is in the above-mentioned range, for example, the adhesive force with the metal layer 6 can be improved. When the storage elastic modulus of the adhesive layer 5 is 50,000 Pa or less, the occurrence of floating between the metal layer 6 under high temperature drying and high temperature and high humidity can be suppressed. In this specification, the "storage elastic modulus of the 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 apparatus, MCR300 manufactured by Physica can be used, for example, as shown in the examples described later.

(metal layer)

The metal layer 6 can be used as a conductive layer for forming the touch sensor of the touch panel. The metal layer 6 is a layer formed of one or more 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. In addition, the passivation film is not counted as one layer in the number of layers.

Metals constituting the metal layer 6 include aluminum (Al), copper (Cu), gold (Au), silver (Ag), titanium (Ti), palladium (Pd), chromium (Cr), nickel (Ni), tungsten ( W), platinum (Pt), iron (Fe), indium (In), tin (Sn), iridium (Ir), rhodium (Rh), neodymium (Nd), molybdenum (Mo) or two or more of these metals alloy. Among these, the metal layer 6 preferably contains aluminum or copper as the main component, and may also contain titanium as an additive. Here, the main component refers to a metal that accounts for 50 mass % or more of the metals constituting the metal layer 6 .

The metal layer 6 may be formed on, for example, a translucent substrate, a continuous film formed over the entire surface of the translucent substrate, or a metal wiring layer formed on the surface of the translucent substrate. The metal wiring layer may be a metal mesh. The translucent base material may be any one having translucency, and examples thereof include films using the resin materials described above as the thermoplastic resin for forming the protective layer, glass films, glass substrates, and the like.

The method of forming the metal layer 6 is not particularly limited, as long as it is formed on the surface of the light-transmitting substrate by, for example, the above-mentioned chemical vapor deposition method, physical vapor deposition method, inkjet printing method, gravure printing method, electroplating, non-metallic coating, etc. It may be formed by electroplating or the like. The metal layer 6 is preferably formed by sputtering.

The thickness of the metal layer 6 is usually 0.01 μm or more, and may be 0.05 μm or more, and from the viewpoint of thinning, preferably 3 μm or less, more preferably 1 μm or less, and still 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, or 3 μm or less, and usually 0.5 μm or more.

(1st bonding layer, 2nd bonding layer, bonding layer (X), bonding layer (Y), bonding layer (Z), bonding layer)

The first and second bonding layers, the bonding layers (X) to (Z), and the bonding layer include an adhesive layer or an adhesive layer.

When each said bonding layer is an adhesive bond layer, it can be formed using the adhesive agent demonstrated in the said adhesive bond layer. When each bonding layer is an adhesive layer, the storage elastic modulus of the adhesive layer is preferably 50,000Pa or more, more preferably 100,000Pa or more, and still more preferably 150,000Pa or more. The storage elastic modulus of the adhesive layer is preferably 200,000 Pa or less from the viewpoint of suppressing the generation of air bubbles during lamination. By setting the storage elastic modulus of the adhesive layer within the above-mentioned range, it is preferable to suppress the occurrence of wrinkles in the cured product layer when the optical layered body 1 is bent, folded, wound, or the like. The measurement method of the storage elastic modulus is as described above. When each bonding layer is an adhesive layer, the thickness of the adhesive layer is preferably 2 μm or more and 20 μm or less, more preferably 4 μm or more and 17 μm or less.

When it is accepted that each of the above-mentioned bonding layers is an adhesive layer, the corrosion of the metal layer 6 is easily suppressed compared with the case where these bonding layers are adhesive layers. When each said bonding layer is an adhesive agent layer, an adhesive agent layer can be formed by hardening the curable component in an adhesive agent. The adhesive for forming the adhesive layer is an adhesive other than a pressure-sensitive adhesive (adhesive), and examples thereof include a water-based adhesive and an active energy ray-curable adhesive.

Examples of the water-based adhesive include those obtained by dissolving or dispersing a polyvinyl alcohol-based resin in water. The drying method in the case of using the water-based adhesive is not particularly limited, and for example, a method of drying using a hot air dryer or an infrared dryer can be employed.

Examples of active energy ray-curable adhesives include solvent-free active-energy ray-curable adhesives containing a curable compound hardened by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Adhesion between layers can be improved by using a solvent-free active energy ray-curable adhesive.

The active energy ray-curable adhesive preferably contains either or both of a cationically polymerizable curable compound and a radically polymerizable curable compound from the viewpoint of exhibiting favorable adhesiveness. The active energy ray-curable adhesive may further contain a cationic polymerization initiator such as a photocationic polymerization initiator for starting the curing reaction of the curable compound, or a radical polymerization initiator.

The cationically polymerizable curable compound includes, for example, an alicyclic epoxy compound having an epoxy group bonded to an alicyclic ring, and a polyfunctional aliphatic ring having two or more epoxy groups and no aromatic ring. Oxygen compounds, monofunctional epoxy groups having one epoxy group (excluding those belonging to alicyclic epoxy compounds), polyfunctional aromatic epoxy compounds having two or more epoxy groups and having aromatic rings, etc. epoxy series compounds; oxetane compounds having one or more oxetane rings in the molecule; combinations of these.

Examples of the radically polymerizable curable compound include (meth)acrylic compounds (compounds having one or more (meth)acryloyloxy groups in the molecule), and radically polymerizable double bonds. other vinyl compounds, or a combination of these.

The active energy ray-curable adhesive may contain a sensitizer such as a photosensitizer as needed. 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. A known sensitizer can be appropriately used. When a 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.

The active energy ray hardening adhesive may contain ion scavengers, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow modifiers, plasticizers, antifoaming agents, antistatic agents, leveling agents, as needed additives, solvents, etc.

When an active energy ray hardening type adhesive is used, an adhesive layer can be formed by irradiating active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays to harden the coating layer of the adhesive. The active energy rays are preferably ultraviolet rays, and the light source at this time can use low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, fluorescent lamps for insect traps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

(Example)

The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these examples. Unless otherwise specified below, the "parts" and "%" indicating the blending amount or content are the quality standards.

(1) Measurement method and evaluation method

[Measurement of moisture permeability]

For the protective layers and barrier layers used in the Examples and Comparative Examples, a constant temperature and humidity tank was used, under the measurement conditions of a temperature of 40° C., a relative humidity of 90% RH, and a measurement time of 24 hours, by the moisture permeability test method (moisture permeability test method). The cup method was used to measure the water vapor transmission rate according to JIS Z 0208), which was used as the moisture permeability.

[Measurement of the amount of iodine in the adhesive layer]

The optical laminates obtained in Examples and Comparative Examples were cut into a size of 25 mm × 50 mm, and an alkali-free glass was attached to the protective layer (COP film with HC) using an adhesive, and the adhesive layer (a) was attached and peeled. The film was prepared as a test piece (1). After storing the test piece (1) in an oven with a temperature of 85° C. and a relative humidity of 85% RH for 240 hours, the release film was peeled off, and the adhesive of the adhesive layer (a) was scraped off. The amount of iodine [ppm] contained in the scraped adhesive was measured by oxidative combustion ion chromatography performed under the following conditions.

<Sample burning>

‧Device: AQF-2100H manufactured by Mitsubishi Chemical Analytech Co., Ltd.

• Combustion conditions: the combustion temperature was set to 1100°C, the gas flow rate was set to 200 mL/min of argon, 400 mL/min of oxygen flow, and 100 mL/min of humidified air flow.

<Ion chromatography>

‧Device: Integrion manufactured by Thermo Fisher Scientific

‧Column: IonPac AS19 manufactured by Thermo Fisher Scientific

・Measurement conditions: the eluent was set to a KOH aqueous solution gradient, the flow rate was set to 1.0 mL/min, the injection volume was set to 100 μL , the measurement mode was set to a suppressor type, and the detector was set to conductive degree detector.

[Measurement of Storage Elastic Modulus of Adhesive Layer]

The storage elastic modulus of the adhesive layers used in Examples and Comparative Examples was measured by the following method. A plurality of sheets were laminated so that the thickness of the adhesive layer would be 0.2 mm. Die the laminated adhesive layer into pieces A cylinder with a diameter of 8 mm was used as a sample for the measurement of the storage elastic modulus. The storage elastic modulus [Pa] was measured by the torsional shearing method according to JIS K7244-6 using a viscoelasticity measuring apparatus (manufactured by Physica, MCR300) on the sample for measurement under the following conditions.

<Measurement conditions>

‧Normal force FN: 1N

‧Strain γ: 1%

‧Frequency: 1Hz

‧Temperature: 25℃

[Evaluation of Corrosion of Metal Layers]

A metal-attached glass substrate (manufactured by GEOMATEC) was prepared by sputtering on the surface of the alkali-free glass with a metal aluminum layer having a thickness of about 500 nm. Next, the optical laminates obtained in the 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 the metal layer was attached to the adhesive layer (a), and the protective layer (HC-attached) was The alkali-free glass was bonded to the COP film) using an adhesive, and a test piece (2) was produced. After storing the test piece (2) in an oven with a temperature of 85°C and a relative humidity of 85% RH for 240 hours, light was irradiated from the back of the glass substrate with the metal layer, and observed through a magnifying glass from the surface of the alkali-free glass on the protective layer side. The state of the metal layer of the test piece (2) (portion to which the cut piece of the optical laminate is attached). Among the observed metal layers, the number of pitting corrosion (holes with a diameter of 0.1 mm or more through which light can pass) was counted and evaluated according to the following criteria.

A: The number of pitting corrosion is less than 4,

B: The number of pitting corrosion is 5 or more and 20 or less,

C: More than 20 pitting corrosion occurred.

(2) Preparation of the layers constituting the optical laminate

[Preparation of Active Energy Ray Curable Adhesives]

The following components were prepared and mixed, followed by defoaming to prepare an active energy ray-curable adhesive.

<Cationically polymerizable compound>

‧Neopentyl glycol diglycidyl ether (trade name: EX-211L, manufactured by Nagase ChemteX Co., Ltd.) 30 parts

‧3-Ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (trade name: OXT-221, manufactured by Toagosei Co., Ltd. ) 13 servings

‧Bisphenol A epoxy resin (trade name: EP-4100E, ADEKA (stock), viscosity 13Pa‧s (temperature 25℃)) 12 parts

‧Aromatic-containing 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

[Production of polarizing plate]

The polyvinyl alcohol film with a thickness of 20 μm , a degree of polymerization of 2,400, and a degree of saponification of 99.9% or more was uniaxially stretched to a stretching ratio of 4.5 times on a roller heated to 125° C. After 30 seconds in water at °C, it was immersed for 30 seconds in a dyeing bath containing 0.05 parts of iodine and 5 parts of potassium iodide per 100 parts of water at 28°C. Next, it was immersed for 110 seconds in a boric acid aqueous solution containing 5.5 parts of boric acid and 15 parts of potassium iodide per 100 parts of water at 64°C. Then, it was immersed in the boric-acid aqueous solution containing 2.35 parts of boric acid and 15 parts of potassium iodide per 100 parts of water at 67°C for 30 seconds. Then, it washed with pure water at 10°C and dried at 80°C to obtain a linear polarizing layer. The thickness of the obtained linearly polarizing layer was 8 μm . Furthermore, a protective layer was attached to one side of the linearly polarizing layer obtained via a water-based adhesive, and dried at 90° C. to obtain a polarizing plate having a protective layer on one side of the linearly polarizing layer. Using a 27 μm -thick cycloolefin film with a hard coat layer (hereinafter sometimes referred to as a “COP film with HC”) as a protective layer, the cycloolefin film side of the COP film with HC was bonded to the linear polarizing layer. The obtained polarizing plate is one in which the HC-attached COP film (protective layer), the adhesive layer (1st bonding layer), and the linear polarizing layer are laminated in this order. The moisture permeability of the HC-attached COP film was 8 g/m ² /24hr.

[Production of retardation layer]

(Production of 1/2 wavelength retardation layer)

A λ/2 alignment treatment is performed by applying a composition for forming an alignment layer on a base material layer formed of a transparent resin and drying it. Next, a composition for forming a liquid crystal layer containing a discotic polymerizable liquid crystal compound is applied on the alignment layer, and heating and UV irradiation are performed to fix the alignment of the polymerizable liquid crystal compound, thereby forming a thickness on the alignment layer of the base material layer. 2 μm as the 1/2 wavelength retardation layer of the hardened material layer.

(Fabrication of λ/4 wavelength retardation layer)

A composition for forming a liquid crystal layer containing a rod-shaped nematic polymerizable liquid crystal compound (liquid crystal monomer) is applied to the rubbing-treated alignment layer on the base material layer formed of a transparent resin, while maintaining the anisotropy of refractive index. By curing in a stable state, a 1/4 wavelength retardation layer as a cured product layer with a thickness of 1 μm was formed on the alignment layer of the base material layer.

(Production of retardation layer with base layer)

Corona treatment was applied to the surface of the 1/2 wavelength retardation layer on the base layer and the surface of the 1/4 wavelength retardation layer on the base layer, respectively. The respective corona-treated surfaces were bonded together using the active energy ray-curable adhesive prepared above so that the angle between the slow axes of the two retardation layers was 60°. Then, from the 1/4 wavelength retardation layer side, ultraviolet irradiation was performed with a cumulative light amount of 400 mJ/cm ² (UV-B) using an ultraviolet irradiation apparatus (manufactured by Fusion UV Systems Co., Ltd.) to harden the active energy ray-curable adhesive. , 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 . Thereby, the base material layer, the alignment layer, the 1/2 wavelength retardation layer (the first cured product layer), the adhesive layer (the bonding layer, the bonding layer (X)), the 1/4 wavelength retardation layer, the adhesive layer (the bonding layer, the bonding layer (X)), and the The retardation layer with the base layer of the difference layer (the second cured product layer), the alignment layer and the base layer. In addition, among the retardation layers with the base material layer, the 1/2 wavelength retardation layer (the first cured product layer), the adhesive layer (the bonding layer, the bonding layer (X)), and the 1/4 wavelength retardation layer The layer (the second cured product layer) constituted the retardation layer in the optical layered bodies of Examples and Comparative Examples, and the thickness of the retardation layer was 6 μm .

(3) Production of optical laminates

[Example 1]

The 1/2 wavelength retardation layer exposed by peeling off the base material layer and the alignment layer on the side of the 1/2 wavelength retardation layer of the retardation layer with the base material layer produced above, and the polarizing plate produced above. The linear polarizing layer side was bonded together using an acrylic adhesive layer (storage elastic modulus: 125,000 Pa) having a thickness of 5 μm . The 1/2 wavelength retardation layer and the polarizing plate were bonded together so that the angle between the slow axis of the 1/2 wavelength retardation layer and the transmission axis of the linear polarizing layer was 15°. Next, the 1/4 wavelength retardation layer exposed by peeling off the alignment layer and the base layer on the side of the quarter wavelength retardation layer was interposed with an acrylic adhesive layer (storage elastic modulus: 125,000) having a thickness of 5 μm . Pa), a cycloolefin film (1) with a thickness of 13 μm (hereinafter sometimes referred to as “COP film”) as a barrier layer obtained by corona treatment on the surface to be in contact with the acrylic adhesive layer is attached. (1)"), an adhesive layer (storage elastic modulus: 25,500 Pa) with a thickness of 15 μm (hereinafter sometimes referred to as “adhesive layer (a)”) was formed on the surface of the COP film to obtain an optical laminate (1).

The optical laminate (1) is formed by sequentially laminating a HC-attached COP film (protective layer, first protective layer), an adhesive layer (first bonding layer), a linear polarizing layer, and an adhesive layer (bonding layer (Y )), 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 Agent layer (lamination layer (Z)), COP film (1) (barrier layer) and adhesive layer (a). Distance D from the surface of the linearly polarizing layer on the 1/2 wavelength retardation layer side to the surface of the adhesive layer (a) on the opposite side to the COP film side (adhesive layer (bonding layer (Y)) The thickness to the adhesive layer (a)) was 44 μm .

The measurement of the moisture permeability of the COP film (1) used in the optical layered body (1), the measurement of the iodine content of the adhesive layer (a) in the optical layered body (1), and the evaluation of the corrosivity of the metal layer were performed. The results are shown in Table 1.

[Example 2]

Optical fibers were obtained in the same manner as in Example 1, except that a 23 μm -thick cycloolefin film (2) (hereinafter sometimes referred to as “COP film (2)”) was used as the barrier layer instead of the COP film (1). Laminate (2).

The optical layered body (2) is formed by sequentially laminating the HC-attached COP film (protective layer, the first protective layer), the adhesive layer (the first bonding layer), the linear polarizing layer, and the adhesive layer (the bonding layer (Y). )), 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 Agent layer (lamination layer (Z)), COP film (2) (barrier layer) and adhesive layer (a). Distance D from the surface on the half wavelength retardation layer side of the linearly polarizing layer to the surface on the opposite side to the COP film side of the adhesive layer (a) (adhesive layer (bonding layer (Y)) The thickness to the adhesive layer (a)) was 54 μm .

The measurement of the water vapor transmission rate of the COP film (2) used for the optical layered body (2), the measurement of the iodine content of the adhesive layer (a) in the optical layered body (2), and the evaluation of the corrosivity of the metal layer were performed. The results are shown in Table 1.

[Example 3]

An optical laminate (3) was obtained in the same manner as in Example 1, except that an acrylic film (hereinafter sometimes referred to as a "PMMA film") having a thickness of 20 μm was used as the barrier layer instead of the COP film (1).

The optical laminate (3) is formed by sequentially laminating a HC-attached COP film (protective layer, first protective layer), an adhesive layer (first bonding layer), a linear polarizing layer, and an adhesive layer (bonding layer (Y). )), 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 Agent layer (lamination layer (Z)), PMMA film (barrier layer) and adhesive layer (a). Distance D from the surface on the half wavelength retardation layer side of the linearly polarizing layer to the surface on the opposite side to the COP film side of the adhesive layer (a) (adhesive layer (bonding layer (Y)) The thickness to the adhesive layer (a)) was 51 μm .

The measurement of the moisture permeability of the PMMA film used in the optical laminate (3), the measurement of the iodine content of the adhesive layer (a) in the optical laminate (3), and the evaluation of the corrosion properties of the metal layer were performed. The results are shown in Table 1.

[Example 4]

A COP film ( 1) An optical laminate (4) was obtained in the same manner as in Example 1, except that the active energy ray-curable adhesive was cured to form an adhesive layer with a thickness of 2 μm .

The optical layered body (4) is formed by sequentially laminating a HC-attached COP film (protective layer, first protective layer), an adhesive layer (first bonding layer), a linear polarizing layer, and an adhesive layer (bonding layer (Y). )), 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 then Agent layer (lamination layer (Z)), COP film (1) (barrier layer) and adhesive layer (a). Distance D from the surface on the half wavelength retardation layer side of the linearly polarizing layer to the surface on the opposite side to the COP film side of the adhesive layer (a) (adhesive layer (bonding layer (Y)) The thickness to the adhesive layer (a)) was 41 μm .

The measurement of the amount of iodine in the adhesive layer (a) in the optical layered body (4) and the evaluation of the corrosivity of the metal layer were performed. The results are shown in Table 1.

[Comparative Example 1]

On the 1/4 wavelength retardation layer exposed by peeling off the alignment layer and the base material layer on the side of the 1/4 wavelength retardation layer, the acrylic adhesive layer and the barrier layer are not provided, but the adhesive layer (a) is directly formed, Except for this, the optical layered body (5) was obtained in the same manner as in Example 1.

The optical laminate (5) is formed by sequentially laminating a HC-attached COP film (protective layer, first protective layer), an adhesive layer (first bonding layer), a linear polarizing layer, and an adhesive layer (bonding layer (Y); )), 1/2 wavelength retardation layer (first cured product layer), adhesive layer (lamination layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer) and adhesive Agent layer (a). Distance D from the surface on the half wavelength retardation layer side of the linearly polarizing layer to the surface on the opposite side to the COP film side of the adhesive layer (a) (adhesive layer (bonding layer (Y)) The thickness to the adhesive layer (a)) was 26 μm .

Measurement of the amount of iodine in the adhesive layer (a) in the optical layered body (5) and evaluation of the corrosiveness of the metal layer were performed. 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 side of the 1/2 wavelength retardation layer, and the linear polarizing layer side of the polarizing plate, were treated with the active energy ray hardening type adhesive prepared above. The optical layered body (6) was obtained in the same manner as in Example 1, except that the active energy ray-curable adhesive was hardened to form an adhesive layer with a thickness of 2 μm .

The optical layered body (6) is formed by sequentially laminating a HC-attached COP film (protective layer, first protective layer), an adhesive layer (first bonding layer), a linear polarizing layer, and an adhesive layer (bonding layer (Y) )), 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 Agent layer (bonding layer (Z)), COP film (1) (barrier layer), and adhesive layer (a). Distance D from the surface on the half wavelength retardation layer side of the linearly polarizing layer to the surface on the opposite side to the COP film side of the adhesive layer (a) (adhesive layer (bonding layer (Y)) The thickness to the adhesive layer (a)) was 41 μm .

Measurement of the amount of iodine in the adhesive layer (a) in the optical layered body (6) and evaluation of the corrosiveness of the metal layer were performed. The results are shown in Table 1.

[Example 6]

The COP film ( 1) An optical laminate (7) was obtained in the same manner as in Example 5, except that the active energy ray-curable adhesive was cured to form an adhesive layer with a thickness of 2 μm .

The optical laminate (7) is formed by sequentially laminating a HC-attached COP film (protective layer, first protective layer), an adhesive layer (first bonding layer), a linear polarizing layer, and an adhesive layer (bonding layer (Y) )), 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 then Agent layer (lamination layer (Z)), COP film (1) (barrier layer) and adhesive layer (a). Distance D from the surface on the half wavelength retardation layer side of the linearly polarizing layer to the surface on the opposite side to the COP film side of the adhesive layer (a) (adhesive layer (bonding layer (Y)) The thickness to the adhesive layer (a)) was 38 μm .

Measurement of the amount of iodine in the adhesive layer (a) in the optical layered body (7) and evaluation of the corrosiveness of the metal layer were performed. 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 20 μm -thick cellulose triacetate film (hereinafter, sometimes referred to as “TAC film”) was used as the barrier layer.

The optical laminate (8) is formed by sequentially laminating a HC-attached COP film (protective layer, first protective layer), an adhesive layer (first bonding layer), a linear polarizing layer, and an adhesive layer (bonding layer (Y). )), 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 then Agent layer (lamination layer (Z)), TAC film (barrier layer) and adhesive layer (a). Distance D from the surface on the half wavelength retardation layer side of the linearly polarizing layer to the surface on the opposite side to the COP film side of the adhesive layer (a) (adhesive layer (bonding layer (Y)) The thickness to the adhesive layer (a)) was 45 μm .

The measurement of the water vapor transmission rate of the TAC film used for the optical laminate (8), the measurement of the iodine content of the adhesive layer (a) in the optical laminate (8), and the evaluation of the corrosivity of the metal layer were performed. The results are shown in Table 1.

[Comparative Example 2]

On the 1/4 wavelength retardation layer exposed by peeling off the alignment layer and the base material layer on the side of the 1/4 wavelength retardation layer, the acrylic adhesive layer and the barrier layer are not provided, but the adhesive layer (a) is directly formed, Except for this, the optical layered body (9) was obtained in the same manner as in Example 5.

The optical laminate (9) is formed by sequentially laminating a HC-attached COP film (protective layer, first protective layer), an adhesive layer (first bonding layer), a linear polarizing layer, and an adhesive layer (bonding layer (Y) )), 1/2 wavelength retardation layer (first cured product layer), adhesive layer (lamination layer, bonding layer (X)), 1/4 wavelength retardation layer (second cured product layer) and adhesive Agent layer (a). Distance D from the surface on the half wavelength retardation layer side of the linearly polarizing layer to the surface on the opposite side to the COP film side of the adhesive layer (a) (adhesive layer (bonding layer (Y)) The thickness to the adhesive layer (a)) was 23 μm .

Measurement of the amount of iodine in the adhesive layer (a) in the optical layered body (9) and evaluation of the corrosiveness of the metal layer were performed. The results are shown in Table 1.

[Table 1]

1,1a: Optical laminate

4: Barrier layer

5: Adhesive layer

10: retardation layer

11: The first hardened material layer (hardened material layer)

21: The first bonding layer

23: Lamination layer (Y)

24: Lamination layer (Z)

30: polarizer

31: Linear polarizing layer

32: The first protective layer (protective layer)

Claims (10)

An optical laminate, which sequentially comprises a linear polarizing layer, a retardation layer, a barrier layer and an adhesive layer; wherein, The aforementioned linear polarizing layer is a polyvinyl alcohol-based resin film with iodine in adsorption alignment, The retardation layer includes at least one cured product layer formed by polymerizing and curing a polymerizable liquid crystal compound, The above-mentioned barrier layer is arranged in direct contact with the above-mentioned adhesive layer, The moisture permeability of the aforementioned barrier layer at a temperature of 40°C and a relative humidity of 90% RH is 1g/m ² /24hr or more and 2000g/m ² /24hr or less, The distance from the surface on the retardation layer side of the linearly polarizing layer to the surface on the opposite side to the barrier layer side of the adhesive layer is 55 μm or less. The optical layered product according to claim 1, wherein the iodine content of the adhesive layer is 250 ppm or less after the optical layered product is stored for 240 hours under conditions of a temperature of 85° C. and a relative humidity of 85% RH. The optical laminate according to claim 1 or 2, wherein the barrier layer is a resin film. The optical laminate according to any one of claims 1 to 3, wherein the retardation layer includes two layers of the hardened material layer, And the said retardation layer contains the bonding layer (X) for bonding the said two hardened|cured material layers mutually. The optical laminate according to claim 4, wherein the bonding layer (X) is an adhesive layer. The optical laminate according to any one of claims 1 to 5, further comprising: a polarizing plate containing the linear polarizing layer, and a bonding layer (Y) for bonding the polarizing plate and the retardation layer together , In the aforementioned polarizing plate, a protective layer is provided on one side or both sides of the aforementioned 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 bonding 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 opposite to the barrier layer side of the adhesive layer. The optical laminate according to claim 9, wherein the metal layer is provided in direct contact with the adhesive layer.

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