JP7261336B1 - Polarizer - Google Patents

Abstract

A polarizing plate having good flexibility and good impact resistance is provided. A polarizing plate includes a polarizer containing a polyvinyl alcohol-based resin and boron, and a protective film. The boron content of the polarizer is 2.8% by mass or more and 4.7% by mass or less. The protective film has a substrate layer and an easily adhesive layer laminated on the polarizer side of the substrate layer. The thickness of the base material layer is 30 μm or less. The thickness of the easy-adhesion layer is 70 nm or more and 800 nm or less. The polarizing plate has a breaking elongation of 4.0% or more and 14.0% or less in both the absorption axis direction and the transmission axis direction at a temperature of 25° C. and a relative humidity of 55%. [Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention relates to a polarizing plate, and further to an optical laminate and a display device.

It is known that a display device such as a liquid crystal display device or an organic EL display device is provided with a polarizing plate on the viewing side thereof. A polarizing plate generally includes a protective film on one or both sides of the polarizer to protect the polarizer. In order to improve the adhesiveness between the protective film and the polarizer, an easy-adhesion layer may be provided on the surface of the protective film (for example, Patent Document 1, etc.).

Japanese Patent No. 6580769

2. Description of the Related Art In recent years, a flexible display device that can be folded or the like has attracted attention. A flexible display device is required to use a polarizing plate that can be repeatedly bent. In a polarizing plate that can be repeatedly bent, there is a tendency to reduce the thickness of the polarizing plate as a whole by reducing the thickness of the polarizer and the protective film in order to obtain good flexibility. tend to decline.

An object of the present invention is to provide a polarizing plate having good flexibility and good impact resistance, and an optical laminate and a display device having the same.

The present invention provides the following polarizing plate, optical laminate and display device.
[1] A polarizing plate comprising a polarizer containing a polyvinyl alcohol-based resin and boron, and a protective film,
The boron content of the polarizer is 2.8% by mass or more and 4.7% by mass or less,
The protective film has a base layer and an easy-adhesion layer laminated on the polarizer side of the base layer,
The thickness of the base material layer is 30 μm or less,
The thickness of the easy-adhesion layer is 70 nm or more and 800 nm or less,
The polarizing plate, wherein the breaking elongation of the polarizing plate in both the absorption axis direction and the transmission axis direction at a temperature of 25° C. and a relative humidity of 55% is 4.0% or more and 14.0% or less.
[2] The polarizing plate of [1], wherein the polarizer has a thickness of 12 μm or less.
[3] The polarizing plate of [1] or [2], wherein the protective film has a puncture elastic modulus of 210 g/mm or more and 550 g/mm or less at a temperature of 25° C. and a relative humidity of 55%.
[4] The polarizing plate according to any one of [1] to [3], wherein the substrate layer is a (meth)acrylic resin film.
[5] The polarizing plate according to any one of [1] to [4], wherein the easy-adhesion layer contains a urethane-based resin.
[6] The polarizing plate according to any one of [1] to [5], wherein the protective film and the polarizer are laminated via a bonding layer.
[7] An optical laminate comprising the polarizing plate according to any one of [1] to [6], a retardation film, and an adhesive layer in this order.
[8] The polarizing plate includes the protective film on one side of the polarizer,
The optical layered body includes a retardation body on the side opposite to the protective film side of the polarizer,
The optical layered product according to [7], wherein the retardation body includes a liquid crystal cured layer.
[9] A display device comprising the optical laminate according to [7] or [8].

The polarizing plate of the present invention can have good flexibility and good impact resistance.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the polarizing plate which concerns on one Embodiment of this invention. 1 is a cross-sectional view schematically showing an optical layered body according to one embodiment of the present invention; FIG. FIG. 2 is a schematic top view of a glued mount having voids used for measuring the puncture modulus of elasticity. (a) is a schematic perspective view showing the main part when the measurement film is attached to the paste-attached mount shown in FIG. 3, and (b) is after the measurement film is attached to the paste-attached mount shown in FIG. FIG. 3 is a diagram schematically showing the upper part of the . FIG. 4 is a diagram schematically showing a cross-section when a needle is pierced into a sample after a measurement film has been attached to the paste-attached mount shown in FIG. 3 ; It is a figure which shows typically the cross section at the time of puncture elastic modulus measurement, (a) and (b) show the state which deformation|transformation has arisen in the measurement film by piercing a measurement film with a needle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

(Polarizer)
FIG. 1 is a cross-sectional view schematically showing a polarizing plate according to one embodiment of the present invention. The polarizing plate 1 of this embodiment includes a polarizer 10 containing a polyvinyl alcohol-based resin and boron, and a protective film 20 . The polarizing plate 1 can be a linear polarizing plate. The protective film 20 has a substrate layer 21 and an easily adhesive layer 22 laminated on the substrate layer 21 on the polarizer 10 side.

The polarizing plate 1 may have the protective film 20 only on one side of the polarizer 10 as shown in FIG. When the polarizer 10 has the protective film 20 only on one side, the protective film 20 is preferably arranged on the viewer side of the polarizer 10 .

As shown in FIG. 1, the polarizer 1 and the protective film 20 are preferably laminated via a first bonding layer 41 (bonding layer). In this case, it is preferable that the easy-adhesion layers 22 of the polarizer 10 and the protective film 20 are in direct contact with the first bonding layer 41 . The first bonding layer 41 is an adhesive layer or a pressure-sensitive adhesive layer, preferably an adhesive layer.

The breaking elongation of the polarizing plate 1 in both the absorption axis direction and the transmission axis direction at a temperature of 25° C. and a relative humidity of 55% is 4.0% or more and 14.0% or less. In the polarizing plate 1, the breaking elongation in the absorption axis direction is usually larger than the breaking elongation in the transmission axis direction, and may be 1.2 times or more, or 1.4 times or more, the breaking elongation in the transmission axis direction. , or 1.5 times or more.

The breaking elongation in the absorption axis direction of the polarizing plate 1 may be 6.0% or more and 13.0% or less, may be 7.0% or more and 12.0% or less, or may be 8.0%. It may be more than or equal to 11.0% or less. The elongation at break in the transmission axis direction of the polarizing plate 1 may be 4.2% or more and 12.0% or less, may be 4.5% or more and 10.0% or less, or may be 4.7%. It may be more than or equal to 9.0% or less, or may be more than or equal to 5.0% and less than or equal to 8.0%. When the breaking elongation of the polarizing plate 1 is within the above range, it becomes easy to achieve both good flexibility and good impact resistance of the polarizing plate 1 . The breaking elongation of the polarizing plate 1 can be adjusted by the type and thickness of the polarizer 10, the type and thickness of the protective film 20, the type and thickness of the base layer 21, the type and thickness of the easy-adhesion layer 22, and the like. . The elongation at break can be measured by the method described in Examples below.

The polarizing plate 1 has a breaking elongation of the polarizing plate 1 in the above range and, as described later, a polarizer 10 having a boron content of 2.8% by mass or more and 4.7% by mass or less, and , a protective film 20 having a base layer 21 with a thickness of 30 μm or less and an easily adhesive layer 22 with a thickness of 70 nm or more and 800 nm or less. Such a polarizing plate 1 can achieve both good flexibility and good impact resistance.

In the present specification, good flexibility refers to cracks occurring in the polarizing plate 1 at the bending axis portion and between layers of the polarizing plate 1 in a bending test of the polarizing plate 1, as described in Examples below. It can be evaluated by peeling off. In the case of the polarizing plate 1 having the protective film 20 only on one side of the polarizer 10, it is preferable to bend the polarizing plate 1 with the protective film 20 side facing inward.

Good impact resistance can be evaluated by cracks, scratches, and the like that occur in the polarizer 10 in an impact resistance test using an evaluation pen, as described in Examples below.

Even when the polarizing plate 1 of the present embodiment is repeatedly bent, peeling between the polarizer 10 and the protective film 20 and cracks occurring in the polarizing plate 1 can be suppressed in the bending axis portion. It can be suitably used for a flexible display device. The bending radius of the bending form of the polarizing plate 1 is not limited. The bending of the polarizing plate 1 includes a form of refraction in which the angle of refraction on the inner surface is greater than 0° and less than 180°, and a form of folding in which the radius of refraction on the inner surface is close to zero or the angle of refraction on the inner surface is 0°. included.

In the polarizing plate 1, the adhesion between the polarizer 10 and the protective film 20 at a temperature of 23° C. and a relative humidity of 60% RH is preferably 1 N or more and 20 N or less, may be 3 N or more and 15 N or less, or 6 N or more. It may be 12N or less. When the adhesion strength of the polarizing plate 1 is within the above range, it becomes easy to obtain the polarizing plate 1 in which peeling occurring between the layers of the polarizing plate 1 due to bending is suppressed. The adhesion strength can be adjusted by a combination of the type of the base layer 21 and the type of the easy-adhesion layer 22 possessed by the protective film 20, the thickness of the easy-adhesion layer 22, and the like.

The polarizing plate 1 may have, for example, a square shape in plan view, preferably a square shape having long sides and short sides, more preferably a rectangle. The entire polarizing plate 1 or one or more of the layers constituting the polarizing plate 1 may have rounded corners, notched ends, or perforated ends.

The thickness of the polarizing plate 1 is not particularly limited as long as it can have good flexibility and good impact resistance, but it is preferably 40 μm or less, more preferably 30 μm or less. The thickness of the polarizing plate 1 is usually 10 μm or more. When the thickness of the polarizing plate 1 is within the above range, the polarizing plate 1 can be further thinned, and the polarizing plate 1 can be easily bent. For example, the thickness of the polarizing plate 1 shown in FIG. 1 is the total thickness of the polarizer 10 and the protective film 20 constituting the polarizing plate 1 and the total thickness of the first bonding layer 41 that bonds them together. say.

The polarizing plate 1 may be a polarizing plate with an adhesive layer by laminating an adhesive layer on one side thereof. The pressure-sensitive adhesive layer-attached polarizing plate may further have a release film that can be peeled off from the pressure-sensitive adhesive layer on the side opposite to the polarizing plate 1 side of the pressure-sensitive adhesive layer. When the polarizing plate 1 shown in FIG. 1 has the protective film 20 only on one side, it is preferable to provide the adhesive layer on the polarizer 10 side.

(Optical laminate)
FIG. 2 is a cross-sectional view schematically showing an optical layered body according to one embodiment of the present invention. The optical layered body 2 has a polarizing plate 1 and a retardation film 30 . The optical laminate 2 may further have an adhesive layer on the side of the retardation film 30 opposite to the polarizing plate 1 side, and the adhesive layer on the opposite side of the retardation film 30 to the It may have a release film that can be separated from the pressure-sensitive adhesive layer. The optical layered body 2 may have a function as, for example, a circularly polarizing plate.

The retardation film 30 included in the optical laminate 2 can include a liquid crystal cured layer. The retardation film 30 is preferably laminated on one side of the polarizer 10, and when the polarizer 10 has the protective film 20 only on one side, for example, as shown in FIG. A retardation element 30 may be provided on the side opposite to the 20 side. In this case, the polarizer 10 and the retardation film 30 are preferably laminated with the second bonding layer 42 interposed therebetween. The second bonding layer 42 may be in direct contact with a later-described retardation layer included in the polarizer 10 and the retardation film 30 . The second bonding layer 42 is an adhesive layer or an adhesive layer, preferably an adhesive layer.

The retardation film 30 may include one or more retardation layers, and the retardation layers may include a liquid crystal cured layer. When the retardation film 30 includes two or more retardation layers, it is preferable that the two or more retardation layers are laminated via a bonding layer. For example, as shown in FIG. 2, the retardation body 30 can be a laminate in which a first retardation layer 31, a third bonding layer 33, and a second retardation layer 32 are laminated in this order. In this case, at least one of the first retardation layer 31 and the second retardation layer 32 preferably contains a liquid crystal cured layer, and both of them may contain a liquid crystal cured layer. The third bonding layer 33 is an adhesive layer or a pressure-sensitive adhesive layer, preferably an adhesive layer.

The first retardation layer 31 may have an alignment layer and a liquid crystal cured layer. The first retardation layer 31 may have an overcoat layer that protects the surface of the liquid crystal cured layer or the alignment layer, a substrate film that supports the alignment layer and the liquid crystal alignment layer, and the like. The second retardation layer 32 may have an alignment layer and a liquid crystal cured layer. The second retardation layer 32 may have an overcoat layer that protects the surface of the liquid crystal cured layer or the alignment layer, a substrate film that supports the alignment layer and the liquid crystal alignment layer, and the like.

When the retardation film 30 has the first retardation layer 31 and the second retardation layer 32, the combination of the first retardation layer 31 and the second retardation layer 32 is, for example, a retardation of [i]λ/4 A combination of a retardation layer (λ / 4 layer) and a retardation layer (λ / 2 layer) that gives a retardation of λ / 2, or [ii] a retardation layer that gives a retardation of λ / 4 ( λ/4 layer) and a positive C layer. The first retardation layer 31 and the second retardation layer 32 may have normal wavelength dispersion or reverse wavelength dispersion. The λ/4 layer may be a reverse wavelength dispersive λ/4 layer. When the retardation film 30 includes the λ/4 layer in the optical layered body 2, the angle between the absorption axis of the polarizer 10 and the slow axis of the λ/4 layer can be 45°±10°. Thereby, the optical layered body 2 has an antireflection function and can function as a circularly polarizing plate.

The thickness of the optical layered body 2 is not particularly limited as long as it can have good flexibility and good impact resistance, but it is preferably 50 μm or less, more preferably 40 μm or less. The thickness of the optical layered body 2 is usually 10 μm or more. When the thickness of the optical layered body 2 is within the above range, the optical layered body 2 can be further thinned, and the optical layered body 2 can be easily bent. For example, the thickness of the optical layered body 2 shown in FIG. It means the sum of the thicknesses of the laminated layer 41 and the second laminated layer 42 .

Details of each layer constituting the polarizing plate 1 and the optical laminate 2 will be described below.
(Polarizer)
A polarizer has a function of selectively transmitting linearly polarized light from non-polarized light such as natural light. The polarizer contains polyvinyl alcohol-based resin and boron. The polarizer is preferably a stretched film to which a dichroic dye is adsorbed. When a dichroic dye is dispersed in a polymer chain (polyvinyl alcohol resin chain) that is anisotropic due to stretching, it appears colored from one direction, and almost colorless from a direction perpendicular to it. Sometimes.

As stretched films with dichroic dyes adsorbed, in addition to polarizers obtained by adsorbing and stretching dichroic dyes on a single polyvinyl alcohol resin film (hereinafter sometimes referred to as "PVA resin film"). , For example, as described in JP-A-2012-73563, on a base film (thermoplastic resin film) such as an ester-based thermoplastic resin film, a polyvinyl alcohol-based resin layer (hereinafter referred to as "PVA resin layer ), stretching the PVA resin layer together with the base material, and then adsorbing and orienting the dichroic dye to produce a polarizer. A polarizer obtained by such a method may be hereinafter referred to as a "stretched layer". A general method for producing this stretched layer will be described later. When the polarizer is a stretched layer, it is manufactured using a suitable base film (thermoplastic resin film) as described above. The configuration supported by The polarizing plate may have a structure in which a base film supporting the polarizer is used as a protective layer for the polarizer.

The polarizer included in the polarizing plate has a boron content of 2.8% by mass or more and 4.7% by mass or less. The boron content of the polarizer may be 3.0% by mass or more and 4.5% by mass or less, or may be 3.2% by mass or more and 4.3% by mass or less. When the boron content of the polarizer is within the above range, the occurrence of cracks due to bending can be suppressed, and a polarizing plate having good impact resistance can be easily obtained. A polarizer having a boron content within the above range can suppress shrinkage in a moist and hot environment.

The boron content of the polarizer is the ratio of the mass of boron contained in the polarizer to the total mass of the polarizer, and can be determined by the method described in Examples below. Boron in the polarizer is considered to exist in a free state as boric acid (H ₃ BO ₃ ), or exist in a state in which boron forms a crosslinked structure with a polyvinyl alcohol-based resin unit. As used herein, the boron content is the amount of boron atoms (B) per se, including those present in the form of compounds as described above. As described later, the boron content of the polarizer can be adjusted by adjusting the amount of boric acid used in the production of the polarizer, treatment conditions with boric acid, or the like.

The contractile force of the polarizer in the absorption axis direction is preferably 2.4 N/2 mm or less, more preferably 2.1 N/2 mm or less. When the shrinkage force of the polarizer in the direction of the absorption axis is within the above range, the occurrence of cracks due to bending can be suppressed, and a polarizing plate having good impact resistance can be easily obtained. The shrinkage force in the absorption axis direction of the polarizer is usually 1.3 N/2 mm or more. The shrinkage force of the polarizer in the direction of the absorption axis is measured for the polarizer held at a temperature of 80° C. for 4 hours as described in Examples below. The shrinkage force of the polarizer in the absorption axis direction can be adjusted by adjusting the boron content, the type and amount of the dichroic dye used in the polarizer, the draw ratio, and the like.

The thickness of the polarizer is usually 30 μm or less, preferably 18 μm or less, more preferably 12 μm or less, and may be 10 μm or less, 9 μm or less, or 8 μm or less. By reducing the thickness of the polarizer, the thickness of the polarizing plate can be reduced, making it easier to achieve a polarizing plate having good flexibility. The thickness of the polarizer is usually 1 μm or more, and may be, for example, 5 μm or more. The thickness of the polarizer can be adjusted by adjusting the thickness and draw ratio of the PVA resin film (original film) before stretching or the PVA resin layer before stretching. When the polarizer is a stretched layer to which a dichroic dye is adsorbed, it can be adjusted by adjusting the thickness and stretching ratio of the PVA resin layer formed on the substrate film.

The polarizer is produced by a process of uniaxially stretching a PVA resin film, a process of dyeing the PVA resin film with a dichroic dye such as iodine to adsorb the dichroic dye, and a process of adsorbing the dichroic dye to the PVA resin. It can be produced through a step of treating the film with an aqueous boric acid solution and a step of washing with water after the treatment with the aqueous boric acid solution. A PVA-based resin film before uniaxial stretching is readily available from the market. The resin may be made into a film. A polyvinyl acetate-based resin may be formed into a film, and the polyvinyl acetate-based resin contained in the film may be saponified.

When the polarizer is a stretched layer to which a dichroic dye is adsorbed, the polarizer is usually formed by applying a coating liquid containing a polyvinyl alcohol-based resin onto the base film to form a PVA resin layer on the base film. A step of forming the formed laminated film (hereinafter sometimes referred to as "PVA laminated film"), a step of uniaxially stretching the obtained PVA laminated film, a PVA resin layer of the uniaxially stretched PVA laminated film, a dichroic dye By dyeing with, a step of adsorbing a dichroic dye to the PVA resin layer to make a polarizer, a step of treating the PVA resin layer on which the dichroic dye is adsorbed with an aqueous boric acid solution, and a treatment with an aqueous boric acid solution. It can be manufactured through a step of washing with water later. The base film used to form the polarizer may be used as a protective layer on the polarizer. If necessary, the base film may be peeled off from the polarizer. The material and thickness of the base film include the material and thickness of the base layer that constitutes the protective film, which will be described later.

A polyvinyl alcohol-based resin is obtained by saponifying a polyvinyl acetate-based resin. Polyvinyl acetate-based resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Other monomers copolymerizable with vinyl acetate include, for example, unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated sulfone compounds, (meth)acrylamide compounds having an ammonium group, and the like. be done. As used herein, (meth)acryl refers to at least one of acryl and methacryl. The same applies to the description of (meth)acryloyl and the like.

The degree of saponification of the polyvinyl alcohol resin is generally about 85 mol % or more and 100 mol % or less, preferably 98 mol % or more. The polyvinyl alcohol-based resin may be modified, and aldehyde-modified polyvinyl formal, polyvinyl acetal, and the like can also be used. The degree of polymerization of the polyvinyl alcohol resin is usually 1000 or more and 10000 or less, preferably 1500 or more and 5000 or less.

As the dichroic dye, iodine and organic dyes can be used, but iodine is preferably used. When iodine is used as a dichroic dye, a polyvinyl alcohol-based resin film or a PVA laminated film containing a base film and a PVA resin layer is usually immersed in a dyeing bath containing iodine and an iodide to obtain a polyvinyl alcohol-based dye. Stain the resin with iodine. Examples of the iodide include potassium iodide and zinc iodide, and potassium iodide is preferred. The content of iodine in this dyeing bath can be 0.003 to 1 part by weight per 100 parts by weight of water. The iodide content can be from 0.15 to 20 parts by weight per 100 parts by weight of water. The temperature of the dyeing bath can be about 10 to 45°C.

In the step of treating a PVA resin film on which iodine is particularly adsorbed as a dichroic dye or a PVA laminated film including a PVA resin layer and a base film with an aqueous boric acid solution, the PVA resin on which a dichroic dye is adsorbed is usually used. A film or PVA laminated film is immersed in an aqueous boric acid solution (crosslinking bath). Boric acid and boron compounds such as borax are used as the boric acid source contained in the boric acid aqueous solution. A cross-linking agent such as glyoxal or glutaraldehyde may be used together with the boron compound. As a solvent for the boric acid aqueous solution, water can be used, and an organic solvent compatible with water may be further included.

The boron content of the polarizer can be controlled by adjusting the conditions of the step of treating the PVA resin film or PVA resin layer to which the dichroic dye is adsorbed with an aqueous boric acid solution. For example, the boron content of the polarizer is adjusted by changing the concentration/amount of boric acid in the boric acid aqueous solution, changing the temperature of the boric acid aqueous solution, or changing the immersion time in the boric acid aqueous solution. be able to. Appropriate preliminary experiments can be conducted to derive the conditions under which the polarizer will have the desired boron content. In order to adjust the boron content of the polarizer, the concentration of boric acid in the boric acid aqueous solution is set to 2.0 to 6.5 parts by mass per 100 parts by mass of water, and the immersion time in the cross-linking bath is adjusted as appropriate. More preferably, the concentration of boric acid is 3.0 to 6.0 parts by mass per 100 parts by mass of water, and the immersion time in the cross-linking bath is appropriately adjusted.

The aqueous boric acid solution can further contain iodide. By adding iodide, the in-plane polarization performance of the obtained polarizer can be made more uniform. Examples of the iodide include the compounds described above, and potassium iodide is preferred. The concentration of iodide in the boric acid aqueous solution is preferably 0.1 to 20 parts by weight per 100 parts by weight of water.

The temperature of the boric acid aqueous solution (crosslinking bath) can be usually 40 to 80°C, preferably 50 to 70°C. If the temperature of the cross-linking bath is too low, the progress of the cross-linking reaction between the polyvinyl alcohol-based resin unit and boron in the PVA resin film or PVA resin layer tends to be insufficient. On the other hand, if the temperature of the cross-linking bath is too high, the PVA resin film or the PVA laminated film is likely to be cut in the cross-linking bath, and the processing stability tends to be remarkably lowered. The immersion time in the cross-linking bath is usually 10 to 600 seconds, preferably 60 to 420 seconds, more preferably 90 to 300 seconds.

The uniaxial stretching of the PVA resin film or PVA laminated film may be performed before dyeing, during dyeing, or in a process of treating with an aqueous boric acid solution after dyeing. Uniaxial stretching may be performed in each step. The PVA resin film or PVA laminated film may be uniaxially stretched in the MD direction (film transport direction). It may be stretched. Also, the PVA resin film or PVA laminated film may be uniaxially stretched in the TD direction (the direction perpendicular to the film transport direction), in which case a so-called tenter method can be used. The stretching may be dry stretching in which the film is stretched in the air, or may be wet stretching in which the PVA resin film or the PVA laminated film is swollen with a solvent and then stretched. In order to exhibit the performance of the polarizer, the draw ratio is 3.0 times or more, preferably 3.5 times or more, and particularly preferably 4.0 times or more. Although the upper limit of the draw ratio is not particularly limited, it is preferably 8.0 times or less from the viewpoint of suppressing breakage or the like.

(Protective film)
The protective film is provided on one side or both sides of the polarizer and has a function of protecting the surface of the polarizer. A protective film has a base material layer and an easy-adhesion layer. The substrate layer and the easy-adhesion layer are usually in direct contact with each other. The easy-adhesion layer is usually provided on one side of the substrate layer, but may be provided on both sides.

The protective film preferably has a puncture elastic modulus E of 210 g/mm or more and 550 g/mm or less at a temperature of 25° C. and a relative humidity of 55%. The piercing elastic modulus E of the protective film may be 250 g/mm or more and 500 g/mm or less, may be 300 g/mm or more and 450 g/mm or less, or may be 320 g/mm or more and 420 g/mm or less. good. When the puncture elastic modulus E of the protective film is within the above range, it becomes easier to achieve the breaking elongation of the polarizing plate in the above range, and a polarizing plate having both good flexibility and good impact resistance is obtained. easier to obtain. The puncture elastic modulus E of the protective film can be adjusted by the type and thickness of the protective film, the type and thickness of the substrate layer, and the like.

A method for measuring the puncture elastic modulus E of the protective film will be described with reference to FIGS. 3 to 6. FIG. In this specification, the piercing elastic modulus E is defined as a 30 mm × 30 mm square cutout at the center of a paste-attached mount 17 having a gap 16 (Fig. 3). Using a measurement sample laminated with a film (measurement film 12) (FIG. 4), a needle with a tip diameter of 1 mmφ0.5R was used at a speed of 0.33 cm/sec in an environment of 25° C. temperature and 55% relative humidity. Penetration perpendicular to the surface of the protective film (measurement film 12) in the gap 16 (FIGS. 5 and 6), the penetration of the protective film (measurement film 12) measured when a break occurs When the amount of displacement due to deflection in the direction is the amount of strain S [mm] and the stress applied to the protective film (measurement film 12) is F [g], the proportionality constant between the stress F and the strain S (stress F / strain S), the equation (1):
Puncture elastic modulus E [g/mm] = F [g]/S [mm] (1)
It is a physical property value calculated by

The puncture modulus E can be measured using a compression tester equipped with a load cell. From the stress-strain curve obtained using such a compression tester, it is possible to measure the stress applied to the measurement film 12 at the time of breakage and the amount of strain that has occurred in the measurement film 12 up to that point. Note that the breakage that occurs in the measurement film 12 when the piercing jig is pressed includes the case where the tip of the jig causes a through hole in the measurement film 12 .

For example, the main part of the method for measuring the puncture elastic modulus E when using a puncture tester "NDG5" manufactured by Kato Tech Co., Ltd. as a compression tester equipped with a load cell will be described. FIG. 3 is a schematic top view of a glued mount 17 having gaps 16 for determining the puncture elastic modulus E of the protective film. As shown in FIG. 3, the paste mount 17 has a 30 mm x 30 mm square hollowed out in the center to serve as a portion to which a protective film to be measured (hereinafter also referred to as "measurement film 12") is adhered. It has a portion (gap portion 16).

4A and 4B are schematic diagrams showing the essential parts when the measurement film 12 is attached to the mount 17 with glue, and FIG. 4A is a perspective view when the measurement film 12 is attached to the mount 17 with glue. 4(b) is a schematic view of the mount 11 with the measurement film after the mount 11 with the measurement film attached to the mount 17 with glue (direction A in FIG. 4(a)). A dashed line in FIG. 4B indicates the outer circumference 18 of the gap 16 . The position M, which is located in the center of the gap 16 and where the needle N pierces, is the intersection of two straight lines connecting obliquely facing points (R and R') on the outer circumference 18 of the gap 16 . FIG. 5 schematically shows a cross-sectional view (before the needle N is pierced) along the line I-I' in the mount 11 with the measurement film shown in FIG.

The needle N is pierced into the central portion M of the measurement film 12 (for example, the intersection of two diagonal lines connecting R and R' among the apexes of the outer circumference 18 of the gap in FIG. 4(b)). In such piercing, the correlation between the stress F [g] applied to the needle N and the strain amount S [mm] due to the bending of the measurement film 12 in the piercing direction is obtained, and the stress F [ g] and the amount of strain S [mm], the puncture elastic modulus E is obtained by the above formula (1). When determining the puncture elastic modulus E, if the measurement film 12 is broken while being deformed (when breaking is caused in the state of FIG. 6A), the measurement film 12 is further deformed. There is a case where breakage occurs (case where breakage occurs in the state of FIG. 6(b)), but the puncture elastic modulus E in this specification can be obtained from the applied stress in the puncture tester and the amount of strain S , the strain amount S may be S when the fracture occurs in the state of FIG. 6(a) or may be S when the fracture occurs in the state of FIG. 6(b). Since the applied stress changes from an increasing tendency to a decreasing tendency when the measurement film 12 breaks, it can be understood that the breaking occurred at this point of change.

The paste for fixing the measurement film 12 on the mount 7 with glue prevents the measurement film 12 from peeling off even partially from the mount 11 with the measurement film during the measurement of the puncture elastic modulus E. If there is, it is not particularly limited. Appropriate preliminary experiments may be conducted to find out the glue for the glued mount 17 to be used for measuring the puncture elastic modulus E.

The thickness of the protective film 20 is 8 μm or more and 31 μm or less, preferably 10 μm or more and 30 μm or less, and may be 15 μm or more and 25 μm or less. When the thickness of the protective film is reduced, the thickness of the polarizing plate can be reduced, making it easier to bend the polarizing plate.

(Base material layer)
The substrate layer that constitutes the protective film has a function of imparting mechanical strength and the like to the protective film and protecting the polarizer.

The thickness of the base material layer is 30 μm or less. The thickness of the base layer may be 8 μm or more and 30 μm or less, 10 μm or more and 29 μm or less, or 15 μm or more and 25 μm or less. When the thickness of the base material layer is reduced, the thickness of the polarizing plate can be reduced, making it easier to bend the polarizing plate.

For the substrate layer, for example, a resin film having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, stretchability and the like can be used. The resin film may be a thermoplastic resin film. Specific examples of such resins include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyethersulfone resins; polysulfone resins; polycarbonate resins; Polyamide resins such as; Polyimide resins; Polyolefin resins such as polyethylene, polypropylene, and ethylene/propylene copolymers; Cyclic polyolefin resins having cyclo and norbornene structures (also referred to as norbornene resins); Resins; polyarylate-based resins; polystyrene-based resins; polyvinyl alcohol-based resins, and mixtures thereof. The resin film is preferably a uniaxially stretched film or a biaxially stretched film.

As the substrate layer, a resin film made of (meth)acrylic resin is preferably used. The (meth)acrylic resin is preferably polymethyl methacrylate resin. The resin film made of (meth)acrylic resin is preferably stretched. A resin film made of a (meth)acrylic resin is preferable because it can have an appropriate puncture elastic modulus E when the thickness is small, particularly when the thickness is 30 μm or less (preferably 25 μm or less).

(Easy adhesion layer)
The easy-adhesion layer constituting the protective film improves the adhesion to the first bonding layer for bonding the protective film and the polarizer, and improves the adhesion between the protective film and the polarizer in the polarizing plate. can be done. Therefore, the easy-adhesion layer is usually provided on the surface of the substrate layer so as to constitute the polarizer-side surface of the protective film.

The thickness of the easy-adhesion layer is 70 nm or more and 800 nm or less. The thickness of the easy adhesion layer may be 80 nm or more and 750 nm or less, 100 nm or more and 700 nm or less, 200 nm or more and 650 nm or less, 280 nm or more and 600 nm or less, or 290 nm or more and 600 nm or less. It may be below. When the thickness of the easy-adhesion layer is within the above range, the adhesion between the protective film and the polarizer can be improved, and it becomes easier to obtain a polarizing plate in which peeling between layers hardly occurs due to bending.

The easy-adhesion layer contains a resin component, and may further contain an additive such as an organic or inorganic filler. The resin component contained in the easy-adhesion layer may be crosslinked. Examples of resin components include urethane-based resins, (meth)acrylic-based resins, polyester-based resins, and the like. The resin component contained in the easy-adhesion layer is preferably a urethane-based resin, and more preferably a polyester-urethane-based resin or a polyether-urethane-based resin. As the resin component, a polyester urethane resin and a polyether urethane resin may be used in combination. A polyester urethane resin is a urethane resin having an ester bond in the main chain of the molecule. A polyether urethane resin is a urethane resin having an ether bond in the main chain of the molecule.

Inorganic fillers include inorganic oxides such as silica, titania, alumina and zirconia; calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate and the like. Examples of organic fillers include silicone resins, fluororesins, and acrylic resins. Among these, silica is preferred, and colloidal silica is more preferred.

The easy-adhesion layer can be formed using an easy-adhesion composition. The easy-adhesion composition can contain a resin component, a filler, a cross-linking agent, a base component, a solvent, and the like, and is preferably a composition in which the resin component is dissolved or dispersed in the solvent. The easy-adhesion composition may contain a monomer and a polymerization initiator for forming the resin component instead of the resin component.

Any cross-linking agent may be used as long as it can react with the cross-linkable functional group of the resin component. When the resin component is a urethane resin having a crosslinkable functional group such as a carboxyl group, a crosslinker containing an amino group, an oxazoline group, an epoxy group, a carbodiimide group, or the like can be used.

Examples of base components include ammonia, amine compounds (primary amine, secondary amine, tertiary amine, etc.), hydrazide compounds, imidazole compounds, imidazoline compounds, and the like.

Solvents include water or water-soluble solvents. Examples of water-soluble solvents include methanol, ethanol, isopropyl alcohol, acetone, tetrahydrofuran, N-methylpyrrolidone, dimethylsulfoxide, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether and the like. Preferably, the solvent is water.

The easy-adhesion layer can be formed by applying an easy-adhesion composition to the surface of the substrate layer facing the polarizer and drying the composition. Examples of the method of applying the adhesive composition include coating methods using a die coater, a comma coater, a reverse roll coater, a gravure coater, a rod coater, a wire bar coater, a doctor blade coater, an air doctor coater, and the like. The easily adhesive composition that has been applied can be dried using, for example, a hot air dryer or an infrared dryer. When the easy-adhesion composition contains a monomer and a polymerization initiator for forming a resin component, the easy-adhesion layer is formed by drying and curing the applied easy-adhesion composition and then providing a curing step as necessary. should be formed.

(Phase difference)
The retarder is a layer that includes a liquid crystal cured layer and imparts retardation to the polarizing plate. The retardation body preferably has one or more retardation layers including a liquid crystal cured layer. When the retardation film includes two or more retardation layers, if at least one retardation layer includes a liquid crystal cured layer, the remaining retardation layers may be formed of stretched films. When the retardation body includes two or more retardation layers, the retardation body preferably has a lamination layer for laminating these layers.

The thickness of the retardation film is, for example, 0.1 μm or more and 50 μm or less, preferably 0.5 μm or more and 30 μm or less, and more preferably 1 μm or more and 10 μm or less.

(Retardation Layer (First Retardation Layer, Second Retardation Layer))
The retardation layer (first retardation layer, second retardation layer) contained in the retardation film may be formed from the resin film exemplified as the material of the base layer constituting the protective film described above, or the liquid crystal It may be formed from a hardened layer. The cured liquid crystal layer is preferably a layer obtained by polymerizing and curing a polymerizable liquid crystal compound. As described above, the first retardation layer and the second retardation layer may contain an alignment layer, a substrate film, an overcoat layer, etc. in addition to the liquid crystal cured layer.

When the cured liquid crystal layer is a layer obtained by polymerizing and curing a polymerizable liquid crystal compound, it can be formed by applying a composition containing a polymerizable liquid crystal compound to a substrate film and curing the composition. An orientation layer may be formed between the substrate film and the coating layer. The material and thickness of the substrate film include the material and thickness of the substrate layer that constitutes the protective film described above.

A polymerizable liquid crystal compound is a compound having at least one polymerizable group and having liquid crystallinity. A known polymerizable liquid crystal compound can be used as the polymerizable liquid crystal compound. The type of polymerizable liquid crystal compound used to form the liquid crystal cured layer is not particularly limited, and rod-like liquid crystal compounds, discotic liquid crystal compounds, and mixtures thereof can be used. A cured product layer formed by polymerizing a polymerizable liquid crystal compound develops retardation by curing in a state in which the polymerizable liquid crystal compound is oriented in a suitable direction. When the rod-shaped polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the planar direction of the optical laminate, the optical axis of the polymerizable liquid crystal compound coincides with the long axis direction of the polymerizable liquid crystal compound. When the discotic polymerizable liquid crystal compound is oriented, the optical axis of the polymerizable liquid crystal compound exists in a direction orthogonal to the discotic surface of the polymerizable liquid crystal compound. As the rod-like polymerizable liquid crystal compound, for example, those described in JP-A-11-513019 (claim 1 etc.) can be preferably used. As the discotic polymerizable liquid crystal compound, JP-A-2007-108732 (paragraphs [0020] to [0067], etc.), JP-A-2010-244038 (paragraphs [0013] to [0108], etc.) described in can be preferably used.

The polymerizable group possessed by the polymerizable liquid crystal compound means a group involved in a polymerization reaction, and is preferably a photopolymerizable group. A photopolymerizable group is a group that can participate in a polymerization reaction by an active radical generated from a photopolymerization initiator, an acid, or the like. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, (meth)acryloyloxy group, oxiranyl group, oxetanyl group, styryl group and allyl group. . Among them, a (meth)acryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferred, and an acryloyloxy group is more preferred. The liquid crystallinity of the polymerizable liquid crystal compound may be either thermotropic liquid crystal or lyotropic liquid crystal, and thermotropic liquid crystal may be classified into nematic liquid crystal or smectic liquid crystal according to the degree of order. When two or more types of polymerizable liquid crystal compounds are used in combination to form a cured product layer of the polymerizable liquid crystal compound, at least one type preferably has two or more polymerizable groups in the molecule.

The liquid crystal cured layer is formed by applying a composition for forming a liquid crystal cured layer containing a polymerizable liquid crystal compound and a solvent, and various additives as necessary, onto the alignment layer described later to form a coating film. By solidifying (curing), a layer in which the polymerizable liquid crystal compound is polymerized and cured can be formed. Alternatively, it may be formed by coating the composition on a substrate film to form a coating film, stretching the coating film together with the substrate film, and curing the coating film. The composition may contain a polymerization initiator, a reactive additive, a leveling agent, a polymerization inhibitor, etc., in addition to the polymerizable liquid crystal compound and solvent described above. As the polymerizable liquid crystal compound, solvent, polymerization initiator, reactive additive, leveling agent, polymerization inhibitor, etc., known ones can be appropriately used.

The thickness of the liquid crystal cured layer may be 0.1 μm or more, 0.5 μm or more, 1 μm or more, 10 μm or less, or 8 μm or less. 5 μm or less, or 3 μm or less.

The orientation layer has an orientation regulating force that orients the polymerizable liquid crystal compound in a desired direction. The alignment layer may be a vertical alignment layer in which the molecular axis of the polymerizable liquid crystal compound is vertically aligned with respect to the planar direction of the optical laminate, or the molecular axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the planar direction of the laminate. It may be an oriented horizontal alignment layer, or an inclined alignment layer in which the molecular axis of the polymerizable liquid crystal compound is tilted with respect to the planar direction of the optical layered body.

The alignment layer has solvent resistance that does not dissolve when a composition for forming a liquid crystal cured layer containing a polymerizable liquid crystal compound is applied, etc., and heat resistance to heat treatment for solvent removal and alignment of the polymerizable liquid crystal compound. is preferred. As the alignment layer, an alignment polymer layer made of an alignment polymer, a photo-alignment polymer layer made of a photo-alignment polymer, an uneven pattern or a plurality of grooves formed by performing a rubbing treatment etc. on the layer surface. A groove oriented layer having

(Lamination layer (first lamination layer, second lamination layer, third lamination layer))
The bonding layers (first bonding layer, second bonding layer, third bonding layer) are adhesive layers or adhesive layers.

The adhesive layer is a layer formed using an adhesive. A pressure-sensitive adhesive exhibits adhesiveness when it is attached to an adherend, and is a so-called pressure-sensitive adhesive. As the adhesive, a known adhesive having excellent optical transparency can be used. Known pressure-sensitive adhesives that can be used include, for example, pressure-sensitive adhesives containing base polymers such as acrylic polymers, urethane polymers, silicone polymers, and polyvinyl ethers. Also, the adhesive may be an active energy ray-curable adhesive, a thermosetting adhesive, or the like. Among these, a pressure-sensitive adhesive containing an acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability (reworkability), weather resistance, heat resistance, etc., is preferable. The pressure-sensitive adhesive layer is preferably composed of a pressure-sensitive adhesive containing a (meth)acrylic resin, a cross-linking agent, and a silane coupling agent, and may contain other components.

The thickness of the adhesive layer is not particularly limited, but is preferably 5 μm or more, may be 10 μm or more, may be 15 μm or more, may be 20 μm or more, or may be 25 μm or more, It is usually 300 μm or less, may be 250 μm or less, may be 100 μm or less, or may be 50 μm or less.

The adhesive layer can be formed using an adhesive composition. Examples of the adhesive composition 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 water-based adhesives include adhesives obtained by dissolving or dispersing polyvinyl alcohol resin in water. The method of drying when a water-based adhesive is used is not particularly limited. For example, a method of drying using a hot air dryer or an infrared ray dryer can be employed.

Active energy ray-curable adhesives include, for example, 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. mentioned. Adhesion between layers can be improved by using a non-solvent active energy ray-curable adhesive.

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

The thickness of the adhesive layer 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.

(Adhesive layer)
As the adhesive layer that the polarizing plate with an adhesive layer has and the adhesive layer that the optical layered body 2 may have, those described above can be used.

(Release film)
The release film that the polarizing plate with an adhesive layer may have and the release film that the optical layered body 2 may have may have a base film and a release treatment layer. The base film may be a resin film. The resin film can be formed, for example, from the material that forms the substrate layer that constitutes the protective film described above. The release treatment layer may be any known release treatment layer, and examples thereof include a layer formed by coating a base film with a release agent such as a fluorine compound or a silicone compound.

(Display device)
The pressure-sensitive adhesive layer-attached polarizing plate and the optical laminate can be used in display devices, and can also be used in flexible display devices. The display device may have a configuration including a display element and a polarizing plate with an adhesive layer or an optical laminate laminated on the viewing side of the display element. The pressure-sensitive adhesive layer-attached polarizing plate and the optical laminate can be bonded to a display element by the pressure-sensitive adhesive layer. When the pressure-sensitive adhesive layer-attached polarizing plate and/or the optical layered body includes a polarizing plate having a protective film only on one side of the polarizer, and the pressure-sensitive adhesive layer-attached polarizing plate and the optical layered body are arranged on the viewing side of the display element, the protective film is preferably positioned closer to the viewing side than the polarizer. The display device is not particularly limited, and examples thereof include image display devices such as organic EL display devices, inorganic EL display devices, liquid crystal display devices, and electroluminescence display devices. The display device may have a touch panel function. The pressure-sensitive adhesive layer-attached polarizing plate and the optical layered body can be suitably used for a flexible display device having flexibility that can be bent or bent.

The display device can be used as mobile devices such as smartphones and tablets, televisions, digital photo frames, electronic signboards, measuring instruments and gauges, office equipment, medical equipment, computing equipment, etc. It is particularly suitable as a display device mounted on a mobile device that requires miniaturization.

EXAMPLES 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.

<Production of polarizer>
(Production of polarizer a)
A polyvinyl alcohol resin film having a thickness of 20 μm, a degree of polymerization of 2400 and a degree of saponification of 99% or more was prepared. This polyvinyl alcohol-based resin film is uniaxially stretched on a hot roll at a draw ratio of 4.1 times, and while maintaining the tension state, 0.05 parts by weight of iodine and 5 parts by weight of potassium iodide are added per 100 parts by weight of water. Then, it was immersed in a dyeing bath at 28°C for 60 seconds.

Then, it was immersed for 110 seconds in a boric acid aqueous solution (1) containing 5.5 parts by mass of boric acid and 15 parts by mass of potassium iodide per 100 parts by mass of water at a temperature of 64°C. After that, it was immersed for 30 seconds in boric acid aqueous solution (2) containing 3.9 parts by mass of boric acid and 15 parts by mass of potassium iodide per 100 parts by mass of water at a temperature of 67°C. After that, it was washed with pure water at a temperature of 10° C. and dried to obtain a polarizer a. The thickness, boron content, and shrinkage force of the polarizer a were measured by the procedures described later. The results are shown in Tables 1 and 2.

(Production of polarizer b)
A polarizer b was produced in the same manner as the polarizer a, except that the boric acid content of the aqueous boric acid solution (2) was changed to 2.3 parts by mass per 100 parts by mass of water. The thickness, boron content, and shrinkage force of the polarizer b were measured by the procedures described later. The results are shown in Tables 1 and 2.

(Production of polarizer c)
A polarizer c was produced in the same manner as the polarizer a, except that the boric acid content of the aqueous boric acid solution (2) was changed to 5.5 parts by mass per 100 parts by mass of water. The thickness, boron content, and shrinkage force of the polarizer c were measured by the procedures described later. The results are shown in Tables 1 and 2.

(Production of polarizer d)
A polarizer d was produced in the same manner as the polarizer a, except that the boric acid content of the aqueous boric acid solution (2) was changed to 6.8 parts by mass per 100 parts by mass of water. The thickness, boron content, and shrinkage force of the polarizer d were measured by the procedures described later. The results are shown in Tables 1 and 2.

(Preparation of polarizer e)
A polarizer e was produced in the same manner as the polarizer a, except that the boric acid content of the boric acid aqueous solution (2) was changed to 1.5 parts by mass per 100 parts by mass of water. The thickness, boron content, and shrinkage force of the polarizer e were measured by the procedures described later. The results are shown in Tables 1 and 2.

[Thickness measurement]
The thickness of each layer of the polarizer, the protective film, and the layer of the retardation film was measured with a contact-type film thickness gauge [trade name “DIGIMICRO (registered trademark) MH-15M” manufactured by Nikon Corporation].

[Boron content in polarizer]
0.2 g of a polarizer was dissolved in 200 g of a 1.9% by mass mannitol aqueous solution. The resulting aqueous solution was titrated with a 1 mol/L NaOH aqueous solution, and the amount of boron (mass) was calculated by comparing the amount of NaOH solution required for neutralization with the calibration curve. The boron content of the polarizer was calculated as the calculated amount of boron relative to the mass of the polarizer.

[Measurement of shrinkage force of polarizer]
A rectangle having a short side of 2 mm and a long side of 50 mm was cut out from the polarizer with a super cutter (manufactured by Ogino Seiki Seisakusho Co., Ltd.) so that the absorption axis of the polarizer coincided with the long side to obtain a test piece. The shrinkage force of the test piece was measured using a thermomechanical analyzer (manufactured by SII Nanotechnology Co., Ltd., model TMA/6100). This measurement was carried out in the constant dimension mode, with a chuck-to-chuck distance of 10 mm, a static load of 0 mN, and a SUS probe used as a jig in the following procedure. First, the test piece was left in a room at a temperature of 20°C for a sufficient period of time. After that, the temperature setting in the room where the test piece was placed was raised from 20° C. to 80° C. in 10 minutes. After the temperature was raised, the room temperature was set to be maintained at 80°C, and after being left for 4 hours, the shrinkage force in the longitudinal direction (absorption axis direction) of the test piece was measured in an environment of 80°C.

<Production of protective film>
(Preparation of easily adhesive composition)
Polyester urethane (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name: Superflex 210, solid content: 33%) 16.8 g, cross-linking agent (oxazoline-containing polymer, manufactured by Nippon Shokubai Co., Ltd., product name: Epocross WS-700, solid content: 25%) 4.2 g, 2.0 g of 1% by mass ammonia water, colloidal silica (manufactured by Fuso Chemical Industry Co., Ltd., Quatron PL-3, solid content: 20% by mass) 0.42 g, and pure water 76.0 g. 6 g were mixed to obtain an easily adhesive composition.

(Preparation of protective film A)
Pellets of polymethyl methacrylate resin [glass transition temperature: 135 ° C., melt viscosity: 700 Pa s (temperature: 270 ° C., shear rate: 100 (1 / sec))], which is an acrylic resin, are passed through a single screw extruder (φ = 20 .0 mm, L/D=25) and a coathanger type T-die (width 150 mm) at a temperature of 280°C. By cooling the extruded resin with a cooling roll maintained at a temperature of 110° C., an unstretched acrylic resin film having a thickness of 80 μm was formed. The unstretched acrylic resin film thus obtained was stretched in the longitudinal direction at a draw ratio of 2.0 using a table stretching machine to obtain a stretched film.

After applying the easily adhesive composition prepared above to one surface of the stretched film using a bar coater, it is put into a hot air dryer and dried at a temperature of 100 ° C. for 90 seconds to obtain a stretched film with a coating film. Obtained. This stretched film with a coating film is stretched in the width direction using a table stretching machine (stretch ratio: 2.35 times), and a protective film A having an easily adhesive layer with a thickness of 600 nm on the surface of a base layer with a thickness of 20 μm. got The puncture elastic modulus E of the protective film A was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film B)
A protective film B having an easily adhesive layer with a thickness of 300 nm on the surface of a substrate layer with a thickness of 20 μm was prepared in the same manner as for the protective film A, except that the thickness of the coating film formed using the easily adhesive composition was changed. Obtained. The puncture elastic modulus E of the protective film B was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film C)
A protective film C having an easy-adhesion layer with a thickness of 280 nm on the surface of a base layer with a thickness of 20 μm was prepared in the same manner as in protective film A, except that the thickness of the coating film formed using the easy-adhesion composition was changed. Obtained. The puncture elastic modulus E of the protective film C was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film D)
A protective film D having an easy-adhesion layer with a thickness of 180 nm on the surface of a substrate layer with a thickness of 20 μm was prepared in the same manner as in protective film A, except that the thickness of the coating film formed using the easy-adhesion composition was changed. Obtained. The puncture elastic modulus E of the protective film D was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film E)
Protective film E having an easy-adhesion layer with a thickness of 80 nm on the surface of a substrate layer with a thickness of 20 μm in the same manner as protective film A, except that the thickness of the coating film formed using the easy-adhesion composition was changed. got The puncture elastic modulus E of the protective film E was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film F)
Protective film F having an easy-adhesion layer with a thickness of 65 nm on the surface of a base layer with a thickness of 20 μm in the same manner as protective film A, except that the thickness of the coating film formed using the easy-adhesion composition was changed. got The puncture elastic modulus E of the protective film F was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film G)
On one surface of a stretched film obtained in the same manner as in the production of protective film A, the easy-adhesive composition prepared above was applied using a bar coater, and then put into a hot air dryer and dried at a temperature of 100 ° C. for 90 minutes. After drying for a second, a stretched film with a coating film was obtained. This stretched film with a coating film is stretched in the width direction using a table stretching machine (stretch ratio: 2.0 times), and a protective film G having an easily adhesive layer with a thickness of 180 nm on the surface of a base layer with a thickness of 40 μm. got The puncture elastic modulus E of the protective film G was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film H)
An unstretched acrylic resin film with a thickness of 20 μm was obtained in the same manner as in the production of protective film A, except that the thickness of the melt-extruded resin was changed by adjusting the coat hanger type T die. On one surface of the obtained unstretched acrylic resin film, the easy-adhesion composition prepared above was applied using a bar coater, then put into a hot air dryer and dried at a temperature of 100° C. for 90 seconds. . As a result, a protective film H having an easily adhesive layer with a thickness of 500 nm on the surface of the substrate layer with a thickness of 20 μm was obtained. The puncture elastic modulus E of the protective film H was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film I)
An unstretched acrylic resin film with a thickness of 40 μm was obtained in the same manner as in the production of the protective film A, except that the thickness of the melt-extruded resin was changed by adjusting the coat hanger type T die. On one surface of the obtained unstretched acrylic resin film, the easy-adhesion composition prepared above was applied using a bar coater, then put into a hot air dryer and dried at a temperature of 100° C. for 90 seconds. . As a result, a protective film I having an easily adhesive layer with a thickness of 500 nm on the surface of the substrate layer with a thickness of 40 μm was obtained. The puncture elastic modulus E of the protective film I was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film J)
Pellets of a thermoplastic resin [glass transition point: 137° C.] containing a norbornene polymer were dried at a temperature of 100° C. for 5 hours. The dried pellets were supplied to an extruder, melted in the extruder, passed through a polymer pipe and a polymer filter, and extruded into a film from a T-die onto a casting drum. By cooling the extruded resin with a casting drum, a long unstretched cyclic polyolefin (COP) resin film having a thickness of 50 μm and a width of 1500 mm was obtained. The COP resin film thus obtained was stretched in the longitudinal direction at a stretching temperature of 145° C. and a stretching ratio of 1.5 to obtain a long stretched COP film having a thickness of 40 μm and a width of 1000 mm.

A manufacturing apparatus was provided comprising a tenter stretcher with inner and outer clip chains and an oven covering the tenter stretcher. The stretched COP film obtained above was continuously supplied to a tenter stretcher and subjected to oblique stretching. The drawing conditions were a draw ratio of 2.1, a drawing temperature of 142° C., and a tension ratio Tin/Tout×100 of the inner clip chain and the outer clip chain of 105%. As a result, a protective film J consisting of only the substrate layer with a thickness of 18 μm was obtained. The puncture elastic modulus E of the protective film J was measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of protective film K)
Polymethyl methacrylate resin, which is an acrylic block copolymer with a core-shell structure [glass transition temperature: 105 ° C., melt viscosity: 700 Pa s (temperature: 240 ° C., shear rate: 100 (1 / sec))] Melt extrusion was carried out at a temperature of 250° C. using a screw extruder (φ=20.0 mm, L/D=25) and a coat hanger type T die (width 150 mm). By cooling the extruded resin with a cooling roll maintained at a temperature of 90° C., a protective film K consisting only of a base layer with a thickness of 25 μm was obtained. The puncture elastic modulus E of the protective film K was measured by the procedure described later. The results are shown in Tables 1 and 2.

[Measurement of Puncture Elastic Modulus E of Protective Film]
A measurement sample was prepared by laminating a protective film to be measured on a paste mount having a gap formed by cutting out a square of 30 mm×30 mm in the center. When the protective film had an easy-adhesion layer, a measurement sample was prepared so that the easy-adhesion layer side of the protective film was the surface to be adhered to the adhesive mount. The central part of the protective film in the void part of the measurement sample is placed on the surface of the protective film with a needle with a tip diameter of 1 mmφ0.5R at a speed of 0.33 cm / sec in an environment with a temperature of 25 ° C. and a relative humidity of 55%. stabbed almost perpendicularly to it. Then, the amount of displacement due to the deflection of the protective film in the thrust direction measured when the break occurs is the strain amount S [mm], the stress applied to the protective film is F [g], and the stress F was divided by the strain amount S to obtain the puncture elastic modulus E [g/mm]. That is, the puncture elastic modulus E was determined by the following formula (1). Tables 1 and 2 show the results.
Puncture elastic modulus E [g/mm] = F [g]/S [mm] (1)

<Preparation of Retardation Element (A) with Base Film>
(Production of first laminate (A))
5 parts by mass of a photo-alignable material having the structure shown below (weight average molecular weight: 30,000) and 95 parts by mass of cyclopentanone were mixed, and the resulting mixture was stirred at 80°C for 1 hour to form an alignment layer. A horizontal alignment layer-forming coating liquid (1) was obtained as a composition for formation.

A leveling agent (F-556; manufactured by DIC Corporation) was added to 100 parts by mass of a mixture obtained by mixing a polymerizable liquid crystal compound a having the structure shown below and a polymerizable liquid crystal compound b at a mass ratio of 90:10. 0 parts by mass, and a polymerization initiator 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one ("Irgacure 369 (Irg369)", manufactured by BASF Japan Ltd.) by 6 masses part was added. Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration was 13%, and the mixture was stirred at 80°C for 1 hour to obtain a liquid crystal layer forming composition as a liquid crystal cured layer forming composition. A coating liquid (1) was obtained.

重合性液晶化合物ｂ：

Polymerizable liquid crystal compound a:

Polymerizable liquid crystal compound b:

Polymerizable liquid crystal compound a was produced by the method described in JP-A-2010-31223. Polymerizable liquid crystal compound b was produced according to the method described in JP-A-2009-173893.

A cycloolefin polymer (COP) film (ZF-14, thickness 23 μm, manufactured by Nippon Zeon Co., Ltd.) as a base film was treated with a corona treatment device (AGF-B10, manufactured by Kasuga Denki Co., Ltd.) with an output of 0.3 kW, Corona treatment was performed once under the condition of a treatment speed of 3 m/min. The horizontal alignment layer forming coating solution (1) was applied by a bar coater to the surface of the substrate film that had been subjected to the corona treatment. The coating film was dried at a temperature of 80° C. for 1 minute, and subjected to polarized UV exposure with an integrated light amount of 100 mJ/cm ² using a polarized UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.). As a result, a substrate film with a horizontal alignment layer was obtained in which a horizontal alignment layer was formed on the substrate film. When the thickness of the horizontal alignment layer was measured with a laser microscope (LEXT, manufactured by Olympus Corporation), it was 100 nm.

Subsequently, in an environment of a temperature of 25° C. and a relative humidity of 30%, the liquid crystal layer-forming coating solution (1) was passed through a PTFE membrane filter with a pore size of 0.2 μm (manufactured by Advantec Toyo Co., Ltd., product number: T300A025A). . Thereafter, this liquid crystal cured layer forming coating solution (1) was applied using a bar coater onto the horizontal alignment layer of the substrate film with the horizontal alignment layer kept at a temperature of 25°C, and the coating layer was heated to 120°C. After drying for 1 minute, a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Ushio Inc.) was used to irradiate ultraviolet rays (under nitrogen atmosphere, wavelength: 365 nm, integrated light amount at wavelength 365 nm: 1000 mJ / cm ² )bottom. The thickness of the obtained first liquid crystal cured layer was measured with a laser microscope (LEXT, manufactured by Olympus Corporation) and found to be 2 μm. As a result, a first laminate (A) in which the first retardation layer was formed on the base film was obtained. The first laminate (A) has, in order from the base film side, an alignment layer and a first liquid crystal cured layer in which a nematic liquid crystal compound is cured, and the first retardation layer is a λ/4 retardation layer.

(Production of second laminate (A))
Polyethylene glycol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-600) 10.0 parts by mass, trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-TMPT) 10.0 parts by mass, 1 , 6-Hexanediol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-HD-N) 10.0 parts by weight, and Irgacure 907 (manufactured by BASF, Irg-907) as a photopolymerization initiator 1.50 parts by weight was dissolved in 70.0 parts by mass of methyl ethyl ketone as a solvent to prepare an orientation layer forming coating liquid (2) as a composition for forming an orientation layer.

A long cyclic olefin resin (COP) film (manufactured by Nippon Zeon Co., Ltd.) having a thickness of 20 μm was prepared as a base film, and the orientation layer forming coating solution (2) was applied to one side of the base film using a bar coater. was coated with After applying a heat treatment at a temperature of 80 ° C. for 60 seconds to the coating layer after coating, ultraviolet rays (UVB) are irradiated at 220 mJ / cm ² to polymerize the monomer components in the coating solution for forming the alignment layer (2). and cured to form an orientation layer having a thickness of 2.3 μm on the substrate film.

As a composition for forming a liquid crystal cured layer, a photopolymerizable nematic liquid crystal compound (manufactured by Merck Ltd., RMM28B) 20.0 parts by mass and Irgacure 907 as a photopolymerization initiator (manufactured by BASF, Irg-907) 1.0 mass parts were dissolved in 80.0 parts by mass of propylene glycol monomethyl ether acetate solvent to prepare liquid crystal layer forming coating solution (2).

The liquid crystal layer forming coating solution (2) was applied onto the alignment layer formed on the substrate film, and the coating layer was heat-treated at 80° C. for 60 seconds. Thereafter, ultraviolet rays (UVB) were irradiated at 220 mJ/cm ² to polymerize and cure the photopolymerizable nematic liquid crystal compound to form a second liquid crystal cured layer having a thickness of 0.7 μm on the alignment layer. As a result, a second laminate (A) was obtained in which a second retardation layer composed of an alignment layer and a second liquid crystal cured layer was formed on the base film. The second retardation layer is a positive C layer. The thickness of the second retardation layer was 3 μm.

(Preparation of Retardation Element (A) with Base Film)
The first laminated body (A) and the second laminated body (A) were laminated such that the first retardation layer side and the second retardation layer side were opposed to each other via an ultraviolet curable adhesive. Next, ultraviolet rays were irradiated to cure the ultraviolet curing adhesive to form an adhesive layer having a thickness of 1 μm, thereby producing a retardation film (A) with a substrate film.

<Preparation of water-based adhesive>
3 parts by mass of carboxyl group-modified polyvinyl alcohol (Kuraray Co., Ltd., trade name "KL-318") is dissolved in 100 parts by mass of water, and a polyamide epoxy additive (Taoka Chemical Industry Co., Ltd.), which is a water-soluble epoxy resin, is added to the aqueous solution. A water-based adhesive was prepared by adding 1.5 parts by mass of 1.5 parts by mass of "Sumireze Resin (registered trademark) 650 (30), an aqueous solution with a solid content concentration of 30% by mass" manufactured by Co., Ltd.

[Examples 1 to 7, Comparative Examples 1 to 8]
(Preparation of polarizing plate)
Using the polarizer and protective film shown in Tables 1 and 2, the protective film is laminated on one side of the polarizer using the water-based adhesive prepared above, and the water-based adhesive is cured to form an adhesive layer (bonding A polarizing plate was produced by forming a layer). When the protective film had an easy-adhesion layer, the polarizer and the protective film were laminated so that the easy-adhesion layer side was on the polarizer side. The breaking elongation and adhesive strength of the produced polarizing plate were measured by the procedure described later. The results are shown in Tables 1 and 2.

(Preparation of acrylic pressure-sensitive adhesive layer a)
Butyl acrylate/acrylic acid copolymer (polymerized using butyl acrylate and acrylic acid at a mass ratio of 95:5, weight average molecular weight 2,000,000, molecular weight distribution (Mw/Mn) 3.0 Copolymer) 100 parts by mass, polyfunctional acrylate monomer (tris (acryloyloxyethyl) isocyanurate (molecular weight: 423, trifunctional type (manufactured by Toagosei Co., Ltd., Aronix M-315) 20 parts, light 1.5 parts by mass of a polymerization initiator (a mixture of benzophenone and 1-hydroxycyclohexylphenyl ketone at a mass ratio of 1:1, manufactured by Ciba Specialty Chemicals, Irgacure 500), and Coronate L (Tosoh Corporation) as a cross-linking agent. A release film (38 μm thick polyethylene After applying the above coating solution to the release-treated surface of a terephthalate release film (SP-PET3811, manufactured by Lintec Co., Ltd.) with a knife-type coating machine so that the thickness after drying and UV irradiation described later becomes 5 μm. A layer of the adhesive composition was formed by drying for 1 minute at a temperature of 90° C. The layer of the adhesive composition was irradiated with ultraviolet rays (illuminance of 600 mW/cm ² , light intensity of 15 mJ/cm ² , an electrodeless electrode manufactured by Fusion Co., Ltd.). Lamp H bulb was used) to obtain an acrylic pressure-sensitive adhesive layer a.The illuminance and light quantity of ultraviolet irradiation were determined using a UV illuminance/photometer (UVPF-36, manufactured by Eyegraphics Co., Ltd.).

(Fabrication of optical laminate)
An optical laminate including the polarizing plate produced above and a retardation film obtained by peeling and removing the two substrate films from the retardation film (A) with the substrate film was produced. The optical laminate was obtained by laminating a retardation film on the side opposite to the protective film side of the polarizing plate via the acrylic pressure-sensitive adhesive layer a obtained above. The retardation film and the polarizing plate were laminated so that the first retardation layer side was on the polarizer side. The produced optical layered body was subjected to an impact resistance test and a bending test according to the procedures described later. The results are shown in Tables 1 and 2.

[Measurement of breaking elongation of polarizing plate]
A polarizing plate having a polarizer and a protective film was measured for elongation at break. A rectangular polarizing plate was cut out so that the length in the direction of the absorption axis was 100 mm and the length in the direction of the transmission axis was 25 mm. Polarized light cut out with a gauge length of 50 mm and a tensile tester (Autograph AG-1S manufactured by Shimadzu Corporation) at a temperature of 25 ° C. and a relative humidity of 55% at a tensile speed of 10 mm / min. A 180° tensile test was performed in the absorption axis direction of the plate to measure the breaking elongation in the absorption axis direction.

A rectangular polarizing plate was cut out so that the length in the transmission axis direction was 100 mm and the length in the absorption axis direction was 25 mm. Polarized light cut out with a gauge length of 50 mm and a tensile tester (Autograph AG-1S manufactured by Shimadzu Corporation) at a temperature of 25 ° C. and a relative humidity of 55% at a tensile speed of 10 mm / min. A 180° tensile test was performed in the transmission axis direction of the plate to measure the elongation at break in the transmission axis direction.

[Measurement of adhesion of polarizing plate]
(Preparation of acrylic pressure-sensitive adhesive layer b)
97.0 parts by mass of n-butyl acrylate, 1.0 part by mass of acrylic acid, and 0.2 parts by mass of 2-hydroxyethyl acrylate were placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device and a nitrogen inlet tube. 5 parts by mass, 200 parts by mass of ethyl acetate, and 0.08 parts by mass of 2,2'-azobisisobutyronitrile were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was heated to 60° C. with stirring under a nitrogen atmosphere, reacted for 6 hours, and then cooled to room temperature to obtain a (meth)acrylate polymer having a weight average molecular weight of 1,800,000. 100 parts by mass of this (meth)acrylic acid ester polymer (solid content conversion value; the same applies hereinafter) and 0.30 parts by mass of trimethylolpropane-modified tolylene diisocyanate (Coronate L, manufactured by Tosoh Corporation) as an isocyanate-based cross-linking agent and 0.30 parts by mass of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403) as a silane coupling agent are mixed, thoroughly stirred, and diluted with ethyl acetate. , to obtain a coating solution of the adhesive composition. After applying the above coating solution to the release-treated surface of the release film (SP-PLR382190, manufactured by Lintec Corporation) with an applicator so that the thickness after drying is 25 μm, dry at a temperature of 100 ° C. for 1 minute. to obtain an acrylic pressure-sensitive adhesive layer b.

(Measurement of adhesion strength)
A rectangular polarizing plate was cut out so that the length in the direction of the absorption axis was 100 mm and the length in the direction of the transmission axis was 25 mm. The polarizer side of the cut-out polarizing plate was press-bonded to alkali-free glass via the acrylic pressure-sensitive adhesive layer b obtained above, autoclaved at a temperature of 50 ° C. under a load of 5 kg for 20 minutes, and then at a temperature of 23 ° C. and a relative humidity. It was allowed to stand in an environment of 60% RH for 10 hours. After that, the edge of the protective film of the polarizing plate which was pressure-bonded to the non-alkali glass was peeled off, and a tensile tester ["Autograph AG-I" manufactured by Shimadzu Corporation] was used to test the tensile speed at a temperature of 25°C. was set to 300 m/min, and a 180° peel test was conducted.

[Impact resistance test of optical laminate (pen drop test)]
Using a super cutter, the optical layered body was cut into a rectangular shape having a length of 150 mm in the direction of the absorption axis and a length of 70 mm in the direction of the transmission axis. The retardation film side of the cut out optical layered body was attached to an acrylic plate via an adhesive layer. In an environment of a temperature of 23° C. and a relative humidity of 55% RH, the pen tip was positioned at a height of 5 cm from the outermost surface of the protective film of the optical laminate laminated to the acrylic plate, and the pen The pen for evaluation was held so that the tip faced downward, and the pen for evaluation was dropped from that position. As the evaluation pen, a pen with a mass of 11 g and a tip diameter of 0.7 mm was used. The optical layered body after dropping the evaluation pen was visually observed and evaluated according to the following criteria. Tables 1 and 2 show the evaluation results.
A: Neither the polarizer nor the protective film has cracks or scratches.
B: The polarizer was neither cracked nor scratched, but the protective film was cracked or scratched.
C: Cracks or scratches are generated in the polarizer.

[Bending test of optical laminate]
The optical layered body was subjected to a bending test for confirming the durability against bending in an environment at a temperature of 25° C. using bending evaluation equipment (manufactured by Science Town, STS-VRT-500). Determine the bending axis, bend with the protective film side inward until the bending radius is 1.5 mm along the bending axis and the areas on both sides of the bending axis are parallel, and then release the bending. was repeated 135,000 times. As bending evaluation (1), peeling along the bending axis was visually determined and evaluated according to the following criteria. As bending evaluation (2), the length of cracks generated along the bending axis was measured and evaluated according to the following criteria.
(Flexion evaluation (1))
AA: No peeling occurred at the bending axis portion of the optical layered body.
A: Punctate peeling occurs at the bending axis portion of the optical layered body.
B: Partial linear peeling occurred at the bending axis portion of the optical layered body.
C: Peeling occurred in the bending axis portion of the optical layered body as a whole.
(Flexion evaluation (2))
A: The crack generated in the bending axis portion of the optical layered body is 1 mm or less.
B: The crack generated in the bending axis portion of the optical layered body is more than 1 mm and 5 mm or less.
C: A crack of more than 5 mm generated in the bending axis portion of the optical layered body.

<Preparation of Retardation Element (B) with Base Film>
(Production of first laminate (B))
A first laminate (B) was prepared in which a first retardation layer was formed on a base film. The first laminate (B) has an alignment layer and a first liquid crystal layer obtained by curing a liquid crystal compound on a base film (cycloolefin polymer film), and the first retardation layer is a λ / 2 retardation layer. is. The first laminate (B) was produced by the procedure for producing the layer B (B-1) described in Example 2 of JP-A-2015-163935.

(Production of second laminate (B))
A second laminate (B) was prepared in which a second retardation layer was formed on a base film. The second laminate (B) has a substrate film (cycloolefin polymer film), an alignment layer, and a second liquid crystal layer in which a liquid crystal compound is cured, and the second retardation layer is a λ / 4 retardation layer. be. The second laminate (B) was produced by the procedure for producing layer A (A-1) described in Example 2 of JP-A-2015-163935.

(Preparation of UV curable adhesive)
A UV-curable adhesive was obtained by mixing the following components.
・3′,4′-Epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (trade name: CEL2021P, manufactured by Daicel Corporation): 70 parts by mass ・Neopentyl glycol diglycidyl ether (trade name: EX-211, Nagasechem) Tex Co., Ltd.): 20 parts by mass 2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Co., Ltd.): 10 parts by mass Cationic polymerization initiator (trade name: CPI-100_50% solution, Sunapro Co., Ltd.): 4.5 parts by mass (substantial solid content: 2.25 parts by mass)
・1,4-diethoxynaphthalene: 2 parts by mass

(Preparation of Retardation Element (B) with Base Film)
The first laminate (B) and the second laminate (B) are laminated so that the first retardation layer side and the second retardation layer side face each other via the UV-curable adhesive prepared above. bottom. Next, ultraviolet rays were irradiated to cure the ultraviolet curing adhesive to form an adhesive layer having a thickness of 1 μm, thereby producing a retardation film (B) with a substrate film.
[Examples 8 to 14]
An optical laminate was produced in the same manner as in Examples 1 to 7, except that the retardation film-attached substrate (B) was used in place of the substrate film-attached retardation film (A). When the optical laminate was subjected to the impact resistance test and bending test according to the above procedures, the results were the same as those of Examples 1-7.

REFERENCE SIGNS LIST 1 polarizing plate 2 optical laminate 10 polarizer 11 mount with measurement film 12 measurement film 16 void 17 mount with glue 18 outer periphery 20 protective film 21 substrate layer 22 easy-adhesion layer 30 Retardation element, 31 first retardation layer, 32 second retardation layer, 33 third bonding layer, 41 first bonding layer (bonding layer), 42 second bonding layer.

Claims (9)

A polarizing plate comprising a polarizer containing a polyvinyl alcohol-based resin and boron, and a protective film,
The boron content of the polarizer is 2.8% by mass or more and 4.7% by mass or less,
The protective film has a base layer and an easy-adhesion layer laminated on the polarizer side of the base layer,
The thickness of the base material layer is 30 μm or less,
The thickness of the easy-adhesion layer is 70 nm or more and 800 nm or less,
The easy-adhesion layer contains a urethane-based resin,
The thickness of the polarizing plate is 40 μm or less,
The polarizing plate, wherein the breaking elongation of the polarizing plate in both the absorption axis direction and the transmission axis direction at a temperature of 25° C. and a relative humidity of 55% is 4.0% or more and 14.0% or less. The polarizing plate according to claim 1, wherein the polarizer has a thickness of 12 µm or less. The polarizing plate according to claim 1 or 2, wherein the protective film has a puncture elastic modulus of 210 g/mm or more and 550 g/mm or less at a temperature of 25°C and a relative humidity of 55%. The polarizing plate according to any one of claims 1 to 3, wherein the base layer is a (meth)acrylic resin film. The polarizing plate according to any one of claims 1 to 4, wherein the urethane-based resin is a polyester urethane-based resin or a polyether urethane-based resin. 6. The polarizing plate according to claim 1, wherein the protective film and the polarizer are laminated via a bonding layer. An optical laminate comprising the polarizing plate according to any one of claims 1 to 6, a retardation film, and an adhesive layer in this order. The polarizing plate includes the protective film on one side of the polarizer,
The optical laminate includes the retardation body on the side opposite to the protective film side of the polarizer,
8. The optical laminate according to claim 7, wherein the retardation body includes a liquid crystal cured layer. A display device comprising the optical layered body according to claim 7 or 8.

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