JP2023150316A - Polarizing plate - Google Patents

Abstract

To provide a polarizing plate having favorable flexibility and favorable impact resistance.SOLUTION: A polarizing plate includes a polarizer containing a polyvinyl alcohol-based resin and boron, and a protective film. A boron content of the polarizer is 2.8 mass% or more and 4.7 mass% or less. The protective film includes a base material layer and an easily adhesive layer laminated on the polarizer side of the base material layer. The thickness of the base material layer is 30 μm or less. The thickness of the easily adhesive layer is 70 nm or more and 800 nm or less. Both fracture elongations of the polarizing plate in an absorption axis direction and a transmission axis direction at a temperature of 25°C and a relative humidity of 55% are 4.0% or more and 14.0% or less.SELECTED DRAWING: Figure 1

Description

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

It is known that a polarizing plate is disposed on the viewing side of a display device such as a liquid crystal display device or an organic EL display device. 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 easily adhesive layer may be provided on the surface of the protective film (for example, Patent Document 1, etc.).

Patent No. 6580769

In recent years, flexible display devices that can be folded and the like have attracted attention. Flexible display devices are required to use polarizing plates that can be repeatedly bent. For polarizing plates that can be repeatedly bent, in order to obtain good flexibility, there is a tendency to reduce the overall thickness of the polarizing plate by reducing the thickness of the polarizer and protective film. Sexuality tends to decrease.

An object of the present invention is to provide a polarizing plate having good flexibility and good impact resistance, and an optical laminate and display device equipped with 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 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 easily adhesive 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 easily adhesive 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%.
[2] The polarizing plate according to [1], wherein the polarizer has a thickness of 12 μm or less.
[3] The polarizing plate according to [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 base layer is a (meth)acrylic resin film.
[5] The polarizing plate according to any one of [1] to [4], wherein the easily adhesive layer contains a urethane 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 material, and an adhesive layer in this order.
[8] The polarizing plate includes the protective film on one side of the polarizer,
The optical laminate includes a retardation member on a side of the polarizer opposite to the protective film side,
The optical laminate according to [7], wherein the retardation body includes a liquid crystal hardening layer.
[9] A display device comprising the optical laminate according to [7] or [8].

According to the polarizing plate of the present invention, it can have good flexibility and good impact resistance.

FIG. 1 is a cross-sectional view schematically showing a polarizing plate according to an embodiment of the present invention. FIG. 1 is a cross-sectional view schematically showing an optical laminate according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a glued mount having voids used for measuring the puncture modulus of elasticity, viewed from above. (a) is a schematic perspective view showing the main parts when pasting the measurement film on the adhesive mount shown in FIG. 3, and (b) is a schematic perspective view after pasting the measurement film on the adhesive mount shown in FIG. It is a figure which shows typically the upper part of. FIG. 4 is a diagram schematically showing a cross section when a needle is pierced into the sample after the measurement film has been pasted onto the glued mount shown in FIG. 3 . It is a figure which shows typically the cross section at the time of a puncture elastic modulus measurement, (a) and (b) show the state where deformation|transformation has arisen in the measurement film by piercing the measurement film with the needle.

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

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

As shown in FIG. 1, the polarizing plate 1 may have the protective film 20 only on one side of the polarizer 10, or may have the protective film 20 on both sides of the polarizer 10. When the polarizer 10 has the protective film 20 on only one side, the protective film 20 is preferably placed on the visible side of the polarizer 10.

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

The elongation at break 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 elongation at break in the absorption axis direction is usually larger than the elongation at break in the transmission axis direction, and may be 1.2 times or more, and may be 1.4 times or more, the elongation at break in the transmission axis direction. It may be 1.5 times or more.

The elongation at break in the absorption axis direction of the polarizing plate 1 may be 6.0% or more and 13.0% or less, 7.0% or more and 12.0% or less, and 8.0%. It may be greater than or equal to 11.0%. 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, 4.5% or more and 10.0% or less, and 4.7%. It may be greater than or equal to 9.0%, or may be greater than or equal to 5.0% and less than or equal to 8.0%. When the elongation at break 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 above-mentioned 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 easily adhesive layer 22, etc. . The elongation at break can be measured by the method described in the 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 having a thickness of 30 μm or less and an easily bonding layer 22 having a thickness of 70 nm or more and 800 nm or less. Such a polarizing plate 1 can have both good flexibility and good impact resistance.

In this specification, good flexibility refers to cracks occurring in the polarizing plate 1 at the bending axis portion and cracks occurring between the layers of the polarizing plate 1 in a bending test of the polarizing plate 1, as described in the Examples described later. It can be evaluated by peeling, etc. In the case of the polarizing plate 1 having the protective film 20 on only one side of the polarizer 10, the above bending is preferably performed with the protective film 20 side facing inside.

Good impact resistance can be evaluated based on cracks, scratches, etc. 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 this embodiment is bent repeatedly, it is possible to suppress the occurrence of peeling between the polarizer 10 and the protective film 20 and the occurrence of cracks in the polarizing plate 1 at the bending axis portion. It can be suitably used for flexible display devices. The bending radius of the polarizing plate 1 is not limited. The bending of the polarizing plate 1 includes a form of refraction in which the refraction angle of the inner surface is greater than 0° and less than 180°, and a form of folding in which the bending radius of the inner surface is close to zero or the refraction angle of 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 1N or more and 20N or less, may be 3N or more and 15N or less, and 6N or more. It may be 12N or less. When the adhesion force in the polarizing plate 1 is within the above range, it becomes easy to obtain a polarizing plate 1 in which peeling between the layers of the polarizing plate 1 that occurs due to bending is suppressed. The above-mentioned adhesion force can be adjusted by the combination of the type of base material layer 21 and the type of easily bonding layer 22 that the protective film 20 has, the thickness of the easily bonding layer 22, and the like.

In plan view, the polarizing plate 1 may have, for example, a rectangular shape, preferably a rectangular shape having long sides and short sides, and more preferably a rectangular shape. The entire polarizing plate 1 or one or more of the layers constituting the polarizing plate 1 may have rounded corners, cutouts, or perforations at the edges.

The thickness of the polarizing plate 1 is not particularly limited as long as it has good flexibility and impact resistance, but 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 made thinner, and the polarizing plate 1 can be easily bent. For example, the thickness of the polarizing plate 1 shown in FIG. 1 refers to the total thickness of the polarizer 10 and the protective film 20 that constitute the polarizing plate 1, and the total thickness of the first bonding layer 41 that joins these together. say.

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

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

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

The retardation body 30 includes one or more retardation layers, and the retardation layers may include a liquid crystal hardening layer. When the retardation body 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 includes a liquid crystal hardening layer, and both may include a liquid crystal hardening layer. The third bonding layer 33 is an adhesive layer or a pressure-sensitive adhesive layer, and is preferably an adhesive layer.

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

When the retardation body 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 has a retardation of [i]λ/4, for example. or [ii] a combination of a retardation layer (λ/4 layer) giving a phase difference of Examples include a combination of a λ/4 layer) and a positive C layer. The first retardation layer 31 and the second retardation layer 32 may have positive wavelength dispersion or reverse wavelength dispersion. The λ/4 layer may be a reverse wavelength dispersion λ/4 layer. When the retardation body 30 includes the λ/4 layer in the optical laminate 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 laminate 2 has an antireflection function and can function as a circularly polarizing plate.

The thickness of the optical laminate 2 is not particularly limited as long as it has good flexibility and impact resistance, but is preferably 50 μm or less, more preferably 40 μm or less. The thickness of the optical laminate 2 is usually 10 μm or more. When the thickness of the optical laminate 2 is within the above range, the optical laminate 2 can be further made thinner, and the optical laminate 2 can be easily bent. For example, the thickness of the optical laminate 2 shown in FIG. It refers to the total thickness of the laminating layer 41 and the second laminating layer 42.

The 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 unpolarized light such as natural light. The polarizer contains polyvinyl alcohol resin and boron. The polarizer is preferably a stretched film on which a dichroic dye is adsorbed. When a dichroic dye is dispersed in a polymer chain (polyvinyl alcohol resin chain) that has become anisotropic through stretching, it appears colored from a certain direction, but appears almost colorless from a direction perpendicular to it. Sometimes.

Stretched films with dichroic dyes adsorbed include 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, a polyvinyl alcohol resin layer (hereinafter referred to as "PVA resin layer") is placed on a base film (thermoplastic resin film) such as an ester thermoplastic resin film. ), and then the PVA resin layer is stretched together with the base material, and then the dichroic dye is adsorbed and oriented to produce a polarizer. A polarizer obtained by such a method may be hereinafter referred to as a "stretched layer". Note that a general method for manufacturing 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 shown above. The configuration is supported by The polarizing plate may have a structure in which the base film supporting the polarizer serves as a protective layer for the polarizer.

The boron content of the polarizer included in the polarizing plate is 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 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 heat 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 the Examples below. It is thought that boron in the polarizer exists in a free state as boric acid (H ₃ BO ₃ ) or in a state where boron forms a crosslinked structure with a unit of a polyvinyl alcohol resin. In this specification, the boron content is the amount of boron atoms (B) themselves, including those present in the form of compounds as described above. The boron content of the polarizer can be adjusted by adjusting the amount of boric acid used in manufacturing the polarizer, the conditions for treatment with boric acid, etc., as described below.

The contraction 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 in the absorption axis direction 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. The shrinkage force of the polarizer in the absorption axis direction is usually 1.3 N/2 mm or more. The shrinkage force in the direction of the absorption axis of the polarizer is measured on a polarizer maintained 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 the boron content, the type and amount of dichroic dye used in the polarizer, the stretching 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, it is possible to make the polarizing plate thinner, and it becomes easier to realize 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 the thickness and stretching ratio of the PVA resin film (original film) or the PVA resin layer before stretching. When the polarizer is a stretched layer adsorbing a dichroic dye, it can be adjusted by adjusting the thickness and stretching ratio of the PVA resin layer formed on the base film.

Polarizers are produced through a process of uniaxially stretching a PVA resin film, a process of dyeing the PVA resin film with a dichroic dye such as iodine, and adsorbing the dichroic dye, and a PVA resin with the dichroic dye adsorbed. It can be manufactured through the steps of treating the film with an aqueous boric acid solution and washing with water after the treatment with the aqueous boric acid solution. A PVA resin film before uniaxial stretching is easily available on the market, and as described below, a polyvinyl acetate resin is produced by a known method, saponified to produce a polyvinyl alcohol resin, and the polyvinyl alcohol The resin may be formed into a film. The polyvinyl acetate resin may be formed into a film at the stage, and the polyvinyl acetate resin contained in the film may be saponified.

When the polarizer is a stretched layer on which a dichroic dye is adsorbed, the polarizer is usually made by applying a coating liquid containing a polyvinyl alcohol resin onto the base film to form a PVA resin layer on the base film. A step of making the formed laminate film (hereinafter sometimes referred to as "PVA laminate film"), a step of uniaxially stretching the obtained PVA laminate film, and a dichroic dye for the PVA resin layer of the uniaxially stretched PVA laminate film. A process of adsorbing a dichroic dye to the PVA resin layer to make a polarizer by dyeing it with a process, a process of treating the PVA resin layer with the dichroic dye adsorbed with a boric acid aqueous solution, and a process with a boric acid aqueous solution. It can be manufactured through a subsequent step of washing with water. 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 and removed from the polarizer. Examples of the material and thickness of the base film include the material and thickness of the base layer constituting the protective film described below.

Polyvinyl alcohol resin is obtained by saponifying polyvinyl acetate resin. As the polyvinyl acetate resin, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers copolymerizable therewith are used. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated sulfone compounds, and (meth)acrylamide compounds having an ammonium group. It will be done. In this specification, (meth)acrylic refers to at least one of acrylic and methacryl. The same applies to the description of (meth)acryloyl and the like.

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

Iodine and organic dyes can be used as the dichroic dye, but it is preferable to use iodine. When using iodine as a dichroic dye, usually a polyvinyl alcohol resin film or a PVA laminated film including a base film and a PVA resin layer is immersed in a dyeing bath containing iodine and iodide. Stain the resin with iodine. Examples of the iodide include potassium iodide and zinc iodide, but potassium iodide is preferable. The content of iodine in this dye bath can be from 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. Further, the temperature of the dyeing bath can be about 10 to 45°C.

In the process of treating a PVA resin film to which iodine has been particularly adsorbed as a dichroic dye or a PVA laminated film containing a PVA resin layer and a base film with an aqueous boric acid solution, the PVA resin to which a dichroic dye has been adsorbed is usually used. The film or PVA laminate film is immersed in an aqueous boric acid solution (crosslinking bath). As the boric acid source contained in the boric acid aqueous solution, boron compounds such as boric acid and borax are used. A crosslinking agent such as glyoxal or glutaraldehyde may be used together with the boron compound. Although water can be used as a solvent for the boric acid aqueous solution, it may further contain an organic solvent that is compatible with water.

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 on which the dichroic dye is adsorbed with a boric acid aqueous solution. For example, the boron content of the polarizer can be adjusted by changing the concentration and 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 may be conducted to derive conditions under which the polarizer has 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 should be 2.0 to 6.5 parts by mass per 100 parts by mass of water, and the immersion time in the crosslinking bath should be 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 crosslinking bath is adjusted as appropriate.

The boric acid aqueous 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 generally 40 to 80°C, preferably 50 to 70°C. If the temperature of the crosslinking bath is too low, the crosslinking reaction between the polyvinyl alcohol resin units in the PVA resin film or PVA resin layer and boron tends to proceed insufficiently. On the other hand, if the temperature of the crosslinking bath is too high, the PVA resin film or PVA laminate film is likely to be cut in the crosslinking bath, and processing stability is likely to be significantly reduced. The immersion time in the crosslinking bath is usually 10 to 600 seconds, preferably 60 to 420 seconds, and more preferably 90 to 300 seconds.

The uniaxial stretching of the PVA resin film or PVA laminate film may be carried out before dyeing, during dyeing, or in the step of treatment with a boric acid aqueous solution after dyeing, and these plural 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). In this case, it may be uniaxially stretched between rolls with different circumferential speeds, or it may be uniaxially stretched using hot rolls. It may be stretched. Further, the PVA resin film or PVA laminate film may be uniaxially stretched in the TD direction (direction perpendicular to the film transport direction), and in this case, a so-called tenter method can be used. Further, the above-mentioned stretching may be dry stretching in which the film is stretched in the atmosphere, or wet stretching in which the PVA resin film or PVA laminated film is stretched in a state in which it is swollen with a solvent. In order to exhibit the performance of the polarizer, the stretching 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 stretching ratio is not particularly limited, it is preferably 8.0 times or less from the viewpoint of suppressing breakage and the like.

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

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

A method of measuring the puncture elastic modulus E of a protective film will be explained with reference to FIGS. 3 to 6. In this specification, the puncture elastic modulus E is defined as the puncture elastic modulus E, as described in the Examples described below, when the adhesive mount 17 (FIG. 3), which has a gap 16 formed by cutting out a 30 mm x 30 mm square in the center, protects Using a measurement sample pasted 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 a temperature of 25°C and a relative humidity of 55%. Pierce the protective film (measurement film 12) perpendicularly to the surface of the protective film (measurement film 12) in the cavity 16 (FIGS. 5 and 6), and measure when breakage 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 stress F and strain S (stress F /strain S), equation (1):
Puncture elastic modulus E [g/mm] = F [g]/S [mm] (1)
This is a physical property value calculated by

The puncture elastic modulus E can be measured using a compression testing machine 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 when the break occurs 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 a through hole is formed in the measurement film 12 by the tip of the jig.

For example, the main part of a method for measuring the puncture elastic modulus E using a puncture tester "NDG5" manufactured by Kato Tech Co., Ltd. as a compression testing machine equipped with a load cell will be described. FIG. 3 is a schematic diagram of a glued mount 17 having a void 16 for determining the puncture elastic modulus E of the protective film, viewed from above. As shown in FIG. 3, the glued mount 17 has a 30 mm x 30 mm square hollowed out in the center, where a protective film for measurement (hereinafter also referred to as "measurement film 12") will be pasted. (void portion 16).

FIG. 4 is a schematic diagram showing the main parts when pasting the measuring film 12 onto the adhesive mount 17, and FIG. 4(a) is a perspective view when pasting the measuring film 12 onto the adhesive mount 17. , FIG. 4(b) is a schematic diagram of the measuring film-attached mount 11 after the measuring film 12 has been bonded to the glue-attached mount 17, viewed from above (direction A in FIG. 4(a)). The broken line in FIG. 4(b) indicates the outer periphery 18 of the cavity 16. The position M where the needle N is inserted, which is located in the center of the cavity 16, is the intersection of two straight lines connecting diagonally opposite points (R and R') on the outer periphery 18 of the cavity 16. FIG. 5 schematically shows a cross-sectional view (before being pierced with the needle N) along II' of the mounting board 11 with the measurement film shown in FIG. 4.

The needle N is inserted into the center M of the measurement film 12 (for example, at the intersection of two diagonal lines connecting R and R' among the vertices of the outer periphery 18 of the gap in FIG. 4(b)). In such piercing, the stress F [g] applied to the needle N is correlated with the amount of strain S [mm] due to the deflection of the measuring film 12 in the piercing direction, and the stress F [ when the measuring film 12 breaks] is calculated. g] and the strain amount S [mm], the piercing elastic modulus E is determined by the above formula (1). When determining the puncture elastic modulus E, if the breakage occurs in a state where the measurement film 12 is deformed (if the breakage occurs in the state shown in FIG. 6(a)), then in a state where the measurement film 12 is further deformed. However, the puncture elastic modulus E in this specification can be determined from the stress applied in the puncture tester and the amount of strain S. The amount of strain S may be S when a break occurs in the state shown in FIG. 6(a), or may be S when a break occurs in the state shown in FIG. 6(b). Note that when the measurement film 12 breaks, the applied stress changes from an upward trend to a downward trend, so it can be understood that a break occurs at this change point.

In the adhesive mount 7, the adhesive for fixing the measurement film 12 is one that can prevent the measurement film 12 from peeling off even partially from the measurement film mount 11 during the measurement of the puncture elastic modulus E. If so, there are no particular limitations. Appropriate preliminary experiments may be conducted to find out the glue of the glued mount 17 used for measuring the puncture modulus of elasticity 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. Reducing the thickness of the protective film allows the polarizing plate to be made thinner, making it easier to bend the polarizing plate.

(Base material layer)
The base layer constituting the protective film has the function of imparting mechanical strength 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 material 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. If the thickness of the base material layer is reduced, the polarizing plate can be made thinner, which makes it easier to bend the polarizing plate.

For example, a resin film having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, stretchability, etc. can be used for the base layer. The resin film may be a thermoplastic resin film. Specific examples of such resins include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether sulfone resins; polysulfone resins; polycarbonate resins; nylon and aromatic polyamides. polyamide resins such as; polyimide resins; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; cyclic polyolefin resins with cyclo and norbornene structures (also referred to as norbornene resins); (meth)acrylic resins Examples include resins; polyarylate resins; polystyrene resins; polyvinyl alcohol resins, and mixtures thereof. The resin film is preferably a uniaxially stretched film or a biaxially stretched film.

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

(Easy adhesive layer)
The easy adhesion layer constituting the protective film improves the adhesiveness to the first laminating layer for laminating the protective film and the polarizer, and improves the adhesiveness between the protective film and the polarizer in the polarizing plate. I can do it. Therefore, the easily adhesive layer is usually provided on the surface of the base material layer so as to constitute the surface of the protective film on the polarizer side.

The thickness of the easily adhesive layer is 70 nm or more and 800 nm or less. The thickness of the easily adhesive 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, and 290 nm or more and 600 nm or less. It may be the following. When the thickness of the easily bonding layer is within the above range, it is possible to improve the adhesion between the protective film and the polarizer, and it is also easier to obtain a polarizing plate that is less likely to peel off between the layers upon bending.

The easily adhesive layer contains a resin component, and may further contain an organic or inorganic filler additive. The resin component contained in the easily adhesive layer may be crosslinked. Examples of the resin component include urethane resin, (meth)acrylic resin, and polyester resin. The resin component contained in the easily adhesive layer is preferably a urethane resin, more preferably a polyester urethane resin or a polyether urethane 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. Polyether urethane resin is a urethane resin having an ether bond in the main chain of the molecule.

Examples of the inorganic filler 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 the organic filler include silicone resin, fluororesin, and acrylic resin. Among these, silica is preferred, and colloidal silica is more preferred.

The easily adhesive layer can be formed using an easily adhesive composition. The easily adhesive composition may contain a resin component, a filler, a crosslinking agent, a base component, a solvent, etc., and is preferably a composition in which the resin component is dissolved or dispersed in a solvent. Instead of the resin component, the easily adhesive composition may contain a monomer and a polymerization initiator for forming the resin component.

Any crosslinking agent may be used as long as it is capable of reacting with the crosslinkable 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 crosslinking agent containing an amino group, an oxazoline group, an epoxy group, a carbodiimide group, or the like can be used.

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

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

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

(phase difference material)
A retardation body is a layer that includes a liquid crystal hardening layer and provides a retardation to a polarizing plate. It is preferable that the retardation body has one or more retardation layers including a liquid crystal hardening layer. When the retardation body includes two or more retardation layers, and at least one retardation layer includes a liquid crystal hardening layer, the remaining retardation layers may be formed of a stretched film. When the retardation material includes two or more retardation layers, the retardation material preferably has a bonding layer for bonding these layers together.

The thickness of the retardation body 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) included in the retardation material may be formed from the resin film exemplified as the material for the base layer constituting the above-mentioned protective film, or may be formed from the resin film exemplified as the material for the base layer constituting the protective film described above. It may also be formed from a hardened layer. The liquid crystal cured layer is preferably a layer formed by polymerizing and curing a polymerizable liquid crystal compound. As described above, the first retardation layer and the second retardation layer may include an alignment layer, a base film, an overcoat layer, etc. in addition to the liquid crystal hardening layer.

When the liquid crystal cured layer is a layer formed by polymerizing and curing a polymerizable liquid crystal compound, it can be formed by applying a composition containing the polymerizable liquid crystal compound to a base film and curing it. An alignment layer may be formed between the base film and the coating layer. Examples of the material and thickness of the base film include the material and thickness of the base layer that constitutes the above-mentioned protective film.

A polymerizable liquid crystal compound is a compound that has at least one polymerizable group and has liquid crystallinity. As the polymerizable liquid crystal compound, a known polymerizable liquid crystal compound can be used. 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 material layer formed by polymerizing a polymerizable liquid crystal compound exhibits a retardation by curing the polymerizable liquid crystal compound while oriented in a suitable direction. When the rod-shaped polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the plane 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 disc-shaped polymerizable liquid crystal compound is oriented, the optical axis of the polymerizable liquid crystal compound is in a direction perpendicular to the disc surface of the polymerizable liquid crystal compound. As the rod-shaped polymerizable liquid crystal compound, for example, those described in Japanese Patent Publication No. 11-513019 (claim 1, etc.) can be suitably used. Disc-shaped polymerizable liquid crystal compounds include those described in JP-A-2007-108732 (paragraphs [0020] to [0067], etc.) and JP-A-2010-244038 (paragraphs [0013] to [0108], etc.). can be suitably used.

The polymerizable group that the polymerizable liquid crystal compound has means a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. The photopolymerizable group refers to a group that can participate in a polymerization reaction by active radicals, acids, etc. generated from a photopolymerization initiator. 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, allyl group, etc. . Among these, (meth)acryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferred, and acryloyloxy group is more preferred. The liquid crystallinity of the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, and if the thermotropic liquid crystal is classified by the degree of order, it may be a nematic liquid crystal or a smectic liquid crystal. When using two or more kinds of polymerizable liquid crystal compounds in combination to form a cured product layer of the polymerizable liquid crystal compound, it is preferable that at least one kind has two or more polymerizable groups in the molecule.

The liquid crystal hardening layer is formed by applying a composition for forming a liquid crystal hardening layer containing a polymerizable liquid crystal compound, a solvent, and various additives as necessary onto the alignment layer described below to form a coating film. By solidifying (hardening), a layer in which the polymerizable liquid crystal compound is polymerized and hardened can be formed. Alternatively, the composition may be applied onto a base film to form a coating film, and this coating film may be stretched and cured together with the base film. In addition to the polymerizable liquid crystal compound and solvent described above, the composition may also contain a polymerization initiator, a reactive additive, a leveling agent, a polymerization inhibitor, and the like. As the polymerizable liquid crystal compound, solvent, polymerization initiator, reactive additive, leveling agent, polymerization inhibitor, etc., known ones can be used as appropriate.

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

The alignment layer has an alignment regulating force that aligns 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 aligned perpendicularly to the plane direction of the optical laminate, or a vertical alignment layer in which the molecular axis of the polymerizable liquid crystal compound is aligned horizontally to the plane direction of the laminate. It may be an oriented horizontal alignment layer, or it may be an inclined alignment layer that aligns the molecular axis of the polymerizable liquid crystal compound obliquely with respect to the plane direction of the optical laminate.

The alignment layer has a solvent resistance that does not dissolve when coating a composition for forming a liquid crystal hardened layer containing a polymerizable liquid crystal compound, and has heat resistance against solvent removal and heat treatment for aligning the polymerizable liquid crystal compound. It is preferable to have the following. As the alignment layer, an oriented polymer layer formed of an oriented polymer, a photo-aligned polymer layer formed of a photo-aligned polymer, an uneven pattern or a plurality of grooves formed by rubbing the layer surface, etc. Examples include a groove orientation layer having the following.

(Lamination layer (first lamination layer, second lamination layer, third lamination layer))
The bonding layer (first bonding layer, second bonding layer, third bonding layer) is an adhesive layer or a pressure-sensitive adhesive layer.

The adhesive layer is a layer formed using an adhesive. An adhesive exhibits adhesive properties by pasting itself onto an adherend, and is a so-called pressure-sensitive adhesive. As the adhesive, a known adhesive having excellent optical transparency can be used. As a known adhesive, for example, an adhesive containing a base polymer such as an acrylic polymer, a urethane polymer, a silicone polymer, or a polyvinyl ether can be used. Further, the adhesive may be an active energy ray-curable adhesive, a thermosetting adhesive, or the like. Among these, a pressure-sensitive adhesive having an acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability (reworkability), weather resistance, heat resistance, etc., is suitable. The adhesive layer is preferably composed of an adhesive containing a (meth)acrylic resin, a crosslinking agent, and a silane coupling agent, and may also 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, 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 in which polyvinyl alcohol resin is dissolved or dispersed in water. The drying method when using a water-based adhesive is not particularly limited, but for example, a method of drying using a hot air dryer or an infrared dryer can be adopted.

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

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

The thickness of the adhesive layer is preferably 0.1 μm or more, may be 0.5 μm or more, and is 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 laminate 2 may have, those described above can be used.

(Release film)
The release film that the adhesive layer-attached polarizing plate may have and the release film that the optical laminate 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 base layer that constitutes the above-mentioned protective film. The release treatment layer may be any known release treatment layer, such as a layer formed by coating a base film with a release agent such as a fluorine compound or a silicone compound.

(display device)
The polarizing plate with an adhesive layer and the optical laminate can be used for display devices, and can also be used for flexible display devices. The display device may be configured to include a display element and a polarizing plate with an adhesive layer or an optical laminate laminated on the viewing side of the display element. A polarizing plate with an adhesive layer and an optical laminate can be bonded to a display element using the adhesive layer. When the polarizing plate with an adhesive layer and/or the optical laminate has a protective film on only one side of the polarizer, and the polarizing plate with an adhesive layer and the optical laminate are placed on the viewing side of the display element, the protective film It is preferable that the polarizer be located 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 electroluminescent display devices. The display device may have a touch panel function. The polarizing plate with an adhesive layer and the optical laminate can be suitably used in a flexible display device having flexibility that allows bending or folding.

Display devices can be used as mobile devices such as smartphones and tablets, televisions, digital photo frames, electronic signboards, measuring instruments and instruments, office equipment, medical equipment, computer equipment, etc., but in particular, they will continue to become more popular in the future. It is particularly suitable as a display device installed in a mobile device that requires miniaturization.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

<Preparation of polarizer>
(Preparation 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 was uniaxially stretched at a stretching ratio of 4.1 times on a hot roll, and while maintaining tension, 0.05 parts by mass of iodine and 5 parts by mass of potassium iodide were added per 100 parts by mass of water. The sample was immersed in a dyeing bath at 28°C for 60 seconds.

Next, 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. Thereafter, it was immersed for 30 seconds in a 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. Thereafter, 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 polarizer a were measured using the procedures described below. The results are shown in Tables 1 and 2.

(Preparation of polarizer b)
Polarizer b was produced in the same manner as polarizer a, except that the boric acid content of the boric acid aqueous 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 polarizer b were measured using the procedures described below. The results are shown in Tables 1 and 2.

(Preparation of polarizer c)
Polarizer c was produced in the same manner as polarizer a, except that the boric acid content of the boric acid aqueous 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 polarizer c were measured using the procedures described below. The results are shown in Tables 1 and 2.

(Preparation of polarizer d)
Polarizer d was produced in the same manner as polarizer a, except that the boric acid content of the boric acid aqueous 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 polarizer d were measured using the procedures described below. The results are shown in Tables 1 and 2.

(Preparation of polarizer e)
Polarizer e was produced in the same manner as 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 polarizer e were measured using the procedures described below. The results are shown in Tables 1 and 2.

[Measurement of thickness]
The thickness of each layer of the polarizer, protective film, and retardation material was measured using a contact film thickness meter [trade name "DIGIMICRO (registered trademark) MH-15M" manufactured by Nikon Corporation].

[Boron content of polarizer]
0.2 g of a polarizer was dissolved in 200 g of a 1.9% by mass mannitol aqueous solution. The obtained 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 a 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]
The polarizer was cut into a rectangle with a short side of 2 mm and a long side of 50 mm using a super cutter (manufactured by Ogino Seiki Seisakusho Co., Ltd.) to prepare a test piece so that the absorption axis of the polarizer coincided with the long side. 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 an inter-chuck distance of 10 mm, a static load of 0 mN, and an SUS probe as the jig, using the following procedure. First, the test piece was left in a room at a temperature of 20° C. for a sufficient period of time. Thereafter, the temperature setting in the room where the test piece was placed was raised from 20°C to 80°C in 10 minutes. After raising the temperature, the room temperature was set to be maintained at 80°C, and after being left for another 4 hours, the shrinkage force in the long side direction (absorption axis direction) of the test piece was measured in an environment at a temperature of 80°C.

<Production of protective film>
(Preparation of easily adhesive composition)
Polyester urethane (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Superflex 210, solid content: 33%) 16.8 g, crosslinking agent (oxazoline-containing polymer, manufactured by Nippon Shokubai Co., Ltd., product name: Epocross WS-700, solid 25%) 4.2g, 1% by mass ammonia water 2.0g, colloidal silica (Fuso Chemical Co., Ltd., Quartron PL-3, solid content: 20% by mass) 0.42g, and pure water 76%. 6 g were mixed to obtain an easily adhesive composition.

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

The adhesive composition prepared above was applied to one surface of the stretched film using a bar coater, and then put into a hot air dryer and dried at a temperature of 100°C for 90 seconds to obtain a stretched film with a coated film. Obtained. This stretched film with a coating film was stretched in the width direction using a table stretching machine (stretching ratio: 2.35 times), and a protective film A having a 600 nm thick easy-adhesion layer on the surface of a 20 μm thick base material layer was formed. I got it. The puncture elastic modulus E of the protective film A was measured according to the procedure described below. The results are shown in Tables 1 and 2.

(Preparation of protective film B)
A protective film B having a 300 nm thick adhesive layer was formed on the surface of a 20 μm thick base layer using the same method as the protective film A except that the thickness of the coating film formed using the easy adhesive composition was changed. Obtained. The puncture elastic modulus E of the protective film B was measured according to the procedure described below. The results are shown in Tables 1 and 2.

(Preparation of protective film C)
A protective film C having a 280 nm thick adhesive layer was formed on the surface of a 20 μm thick base material layer using the same method as the protective film A except that the thickness of the coating film formed using the easy adhesive composition was changed. Obtained. The puncture elastic modulus E of the protective film C was measured according to the procedure described below. The results are shown in Tables 1 and 2.

(Preparation of protective film D)
Protective film D having a 180 nm thick adhesive layer on the surface of a 20 μm thick base layer was prepared in the same manner as protective film A, except that the thickness of the coating film formed using the adhesive composition was changed. Obtained. The puncture elastic modulus E of the protective film D was measured according to the procedure described below. The results are shown in Tables 1 and 2.

(Preparation of protective film E)
A protective film E having an 80 nm thick easy adhesive layer on the surface of a 20 μm thick base layer was prepared using the same method as the protective film A, except that the thickness of the coating film formed using the easy adhesive composition was changed. I got it. The puncture elastic modulus E of the protective film E was measured according to the procedure described below. The results are shown in Tables 1 and 2.

(Preparation of protective film F)
A protective film F having an easily adhesive layer with a thickness of 65 nm on the surface of a base material layer with a thickness of 20 μm was prepared in the same manner as the protective film A, except that the thickness of the coating film formed using the easily adhesive composition was changed. I got it. The puncture elastic modulus E of the protective film F was measured according to the procedure described below. The results are shown in Tables 1 and 2.

(Preparation of protective film G)
The easy-adhesive composition prepared above was applied to one surface of the stretched film obtained in the same manner as in the preparation of protective film A using a bar coater, and then put into a hot air dryer and dried at a temperature of 100°C for 90 minutes. It was dried for seconds to obtain a stretched film with a coated film. This stretched film with a coated film was stretched in the width direction using a table stretching machine (stretching ratio: 2.0 times), and a protective film G having a 180 nm thick easy-adhesive layer on the surface of a 40 μm thick base material layer was formed. I got it. The puncture elastic modulus E of the protective film G was measured according to the procedure described below. 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 resin to be melt-extruded was changed by adjusting the coat hanger type T die. The easily adhesive composition prepared above was applied to one surface of the obtained unstretched acrylic resin film using a bar coater, and then placed in a hot air dryer and dried at a temperature of 100°C for 90 seconds. . Thereby, a protective film H having a 500 nm thick easily adhesive layer on the surface of a 20 μm thick base material layer was obtained. The puncture elastic modulus E of the protective film H was measured according to the procedure described below. 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 protective film A, except that the thickness of the resin to be melt-extruded was changed by adjusting the coat hanger type T die. The easily adhesive composition prepared above was applied to one surface of the obtained unstretched acrylic resin film using a bar coater, and then placed in a hot air dryer and dried at a temperature of 100°C for 90 seconds. . As a result, a protective film I having a 500 nm thick easy-adhesive layer on the surface of a 40 μm thick base material layer was obtained. The puncture elastic modulus E of the protective film I was measured according to the procedure described below. 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 with 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 times to obtain a long stretched COP film with a thickness of 40 μm and a width of 1000 mm.

A manufacturing apparatus was prepared that included a tenter stretching device with an inner clip chain and an outer clip chain, and an oven covering the tenter stretching device. The stretched COP film obtained above was continuously supplied to a tenter stretching device to perform diagonal stretching. The stretching conditions were a stretching ratio of 2.1 times, a stretching temperature of 142° C., and a tension ratio Tin/Tout×100 of the inner clip chain and the outer clip chain of 105%. Thereby, a protective film J consisting only of a base material layer with a thickness of 18 μm was obtained. The puncture elastic modulus E of the protective film J was measured according to the procedure described below. The results are shown in Tables 1 and 2.

(Preparation of protective film K)
Pellets of 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))], were Melt extrusion was performed at a temperature of 250° C. using a shaft 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 having a thickness of 25 μm and consisting only of a base material layer was obtained. The puncture elastic modulus E of the protective film K was measured according to the procedure described below. 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 glue-backed mount having a gap formed by cutting out a 30 mm x 30 mm square in the center. When the protective film had an easily adhesive layer, the measurement sample was prepared such that the easily adhesive layer side of the protective film was the surface to be bonded to the adhesive mount. A needle with a tip diameter of 1 mmφ0.5R was applied to the surface of the protective film at a speed of 0.33 cm/sec in an environment of a temperature of 25°C and a relative humidity of 55%, at a speed of 0.33 cm/sec. It was stabbed almost perpendicularly. Then, the amount of displacement due to the deflection of the protective film in the thrusting direction measured at the time of breakage is defined as the amount of strain S [mm], the stress applied to the protective film is defined as F [g], and the stress F was divided by the amount of strain S to determine the puncture elastic modulus E [g/mm]. That is, the puncture elastic modulus E was determined using the following equation (1). The results are shown in Tables 1 and 2.
Puncture elastic modulus E [g/mm] = F [g]/S [mm] (1)

<Preparation of retardation material with base film (A)>
(Preparation of first laminate (A))
By mixing 5 parts by mass of a photo-alignable material (weight average molecular weight: 30,000) with the structure shown below and 95 parts by mass of cyclopentanone and stirring the resulting mixture at 80°C for 1 hour, an alignment layer is formed. A coating liquid (1) for forming a horizontal alignment layer 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 of 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 6 parts by mass of 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one ("Irgacure 369 (Irg369)", manufactured by BASF Japan Ltd.), which is a polymerization initiator. Part was added. Furthermore, by adding N-methyl-2-pyrrolidone (NMP) to a solid concentration of 13% and stirring at 80°C for 1 hour, a composition for forming a liquid crystal layer was prepared. 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 No. 2010-31223. Polymerizable liquid crystal compound b was produced according to the method described in JP-A No. 2009-173893.

A cycloolefin polymer (COP) film (manufactured by Nippon Zeon Co., Ltd., ZF-14, thickness 23 μm) 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 at a treatment speed of 3 m/min. The horizontal alignment layer forming coating liquid (1) was applied to the surface of the corona-treated base film using a bar coater. The coating film was dried at a temperature of 80° C. for 1 minute, and polarized UV exposure was performed using a polarized UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.) at an integrated light intensity of 100 mJ/cm ² . Thereby, a base film with a horizontal alignment layer was obtained, in which a horizontal alignment layer was formed on the base film. The thickness of the horizontal alignment layer was measured using a laser microscope (LEXT, manufactured by Olympus Corporation) and was found to be 100 nm.

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

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

A long cyclic olefin resin (COP) film (manufactured by Zeon Corporation) with a thickness of 20 μm was prepared as a base film, and the coating liquid for forming an alignment layer (2) was coated on one side of the base film using a bar coater. It was applied at. After applying heat treatment to the coated layer at a temperature of 80°C for 60 seconds, it was irradiated with ultraviolet light (UVB) at 220 mJ/ ^cm2 to polymerize the monomer components in the alignment layer forming coating liquid (2). This was then cured to form an alignment layer with a thickness of 2.3 μm on the base film.

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

The liquid crystal layer forming coating liquid (2) was applied onto the alignment layer formed on the base film, and the applied layer was heat-treated at a temperature of 80° C. for 60 seconds. Thereafter, the photopolymerizable nematic liquid crystal compound was polymerized and cured by irradiating ultraviolet light (UVB) at 220 mJ/cm ² to form a second liquid crystal cured layer with a thickness of 0.7 μm on the alignment layer. Thereby, a second laminate (A) was obtained in which a second retardation layer consisting 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.

(Production of retardation material (A) with base film)
The first laminate (A) and the second laminate (A) were laminated so that the first retardation layer side and the second retardation layer side faced each other with an ultraviolet curable adhesive interposed therebetween. Next, the ultraviolet curable adhesive was cured by irradiation with ultraviolet rays to form an adhesive layer with a thickness of 1 μm, thereby producing a retardation material with a base film (A).

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

[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 (laminated). A polarizing plate was produced by forming a layer). When the protective film had an easily adhesive layer, the polarizer and the protective film were laminated so that the easily adhesive layer side was on the polarizer side. The elongation at break and adhesion of the produced polarizing plate were measured according to the procedure described below. The results are shown in Tables 1 and 2.

(Preparation of acrylic 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 million, molecular weight distribution (Mw/Mn) 3.0) copolymer), 20 parts of a polyfunctional acrylate monomer (tris(acryloyloxyethyl) isocyanurate (molecular weight: 423, trifunctional type (manufactured by Toagosei Co., Ltd., Aronix M-315), 1.5 parts by mass of a polymerization initiator (a mixture of benzophenone and 1-hydroxycyclohexylphenyl ketone in a mass ratio of 1:1, manufactured by Ciba Specialty Chemicals, Irgacure 500), and Coronate L (Tosoh Corporation) as a crosslinking agent. A coating solution of the adhesive composition was prepared by blending 1 part by mass of KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent and 0.2 parts by mass of KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent. After applying the above coating solution to the release-treated surface of a terephthalate release film (manufactured by Lintec Corporation, SP-PET3811) using a knife-type coating machine so that the thickness after drying and irradiation with ultraviolet rays described below becomes 5 μm. A layer of the adhesive composition was formed by drying at a temperature of 90° C. for 1 minute.The layer of the adhesive composition was irradiated with ultraviolet light (illuminance 600 mW/cm ² , light amount 15 mJ/cm ² , electrodeless manufactured by Fusion). The acrylic adhesive layer a was obtained by using a lamp H bulb.The illuminance and light amount of ultraviolet irradiation were determined using a UV illuminance/photometer (manufactured by Eye Graphics, UVPF-36).

(Preparation of optical laminate)
An optical laminate containing the polarizing plate produced above and a retardation body obtained by peeling and removing two base films from the base film-attached retardation body (A) was produced. The optical laminate was one in which a retardation material was laminated on the opposite side of the polarizing plate from the protective film side via the acrylic adhesive layer a obtained above. The retardation body and the polarizing plate were laminated so that the first retardation layer side was on the polarizer side. The produced optical laminate was subjected to an impact resistance test and a bending test according to the procedure described below. The results are shown in Tables 1 and 2.

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

[Measurement of adhesion of polarizing plate]
(Preparation of acrylic adhesive layer b)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen inlet tube, 97.0 parts by mass of n-butyl acrylate, 1.0 parts by mass of acrylic acid, and 0.0 parts by mass of 2-hydroxyethyl acrylate were added. 5 parts by mass, 200 parts by mass of ethyl acetate, and 0.08 parts by mass of 2,2'-azobisisobutyronitrile, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was heated to 60° C. while stirring under a nitrogen atmosphere, reacted for 6 hours, and then cooled to room temperature to obtain a (meth)acrylic acid ester polymer having a weight average molecular weight of 1.8 million. 100 parts by mass of this (meth)acrylic acid ester polymer (solid content equivalent; the same applies hereinafter) and 0.30 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, Coronate L) as an isocyanate-based crosslinking agent. and 0.30 parts by mass of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403) as a silane coupling agent, stirred thoroughly, and diluted with ethyl acetate. A coating solution of an adhesive composition was obtained. After applying the above coating solution to the release-treated surface of a release film (manufactured by Lintec Corporation, SP-PLR382190) using an applicator so that the thickness after drying is 25 μm, drying at a temperature of 100 ° C. for 1 minute. Thus, an acrylic adhesive layer b was obtained.

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

[Impact resistance test of optical laminate (pen drop test)]
Using a super cutter, the optical laminate was cut into a rectangular shape having a length in the absorption axis direction of 150 mm and a length in the transmission axis direction of 70 mm. The retardation body side of the cut out optical laminate was bonded to an acrylic plate via an adhesive layer. In an environment with 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 against the optical laminate bonded to the acrylic board. The evaluation pen was held with the tip facing downward, and the evaluation pen was dropped from that position. As a pen for evaluation, a pen having a mass of 11 g and a pen tip diameter of 0.7 mm was used. After dropping the evaluation pen, the optical laminate was visually observed and evaluated based on the following criteria. The evaluation results are shown in Tables 1 and 2.
A: No cracks or scratches occurred on either the polarizer or the protective film.
B: No cracks or scratches occur on the polarizer, but cracks or scratches occur on the protective film.
C: Cracks or scratches have occurred in the polarizer.

[Bending test of optical laminate]
The optical laminate was subjected to a bending test to confirm its durability against bending in an environment at a temperature of 25° C. using bending evaluation equipment (STS-VRT-500, manufactured by Science Town). Determine the bending axis, bend it along the bending axis with the protective film side inward until the bending radius is 1.5 mm 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 that occurred along the bending axis was visually judged and evaluated based on the following criteria. As bending evaluation (2), the length of a crack that occurred along the bending axis was measured, and the evaluation was performed based on the following criteria.
(Bending evaluation (1))
AA: No peeling occurred at the bending axis portion of the optical laminate.
A: Point-like peeling occurs at the bent axis portion of the optical laminate.
B: Partial linear peeling occurred at the bent axis portion of the optical laminate.
C: Peeling occurred throughout the bending axis portion of the optical laminate.
(Bending evaluation (2))
A: The crack that occurs in the bending axis portion of the optical laminate is 1 mm or less.
B: The crack that occurs in the bending axis portion of the optical laminate is more than 1 mm and less than 5 mm.
C: Cracks occurring in the bending axis portion of the optical laminate exceed 5 mm.

<Preparation of retardation material with base film (B)>
(Preparation of first laminate (B))
A first laminate (B) in which a first retardation layer was formed on a base film was prepared. The first laminate (B) has an alignment layer and a first liquid crystal layer in which a liquid crystal compound is cured on a base film (cycloolefin polymer film), and the first retardation layer is a λ/2 retardation layer. It is. The first laminate (B) was produced using the procedure for manufacturing layer B (B-1) described in Example 2 of JP-A-2015-163935.

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

(Preparation of ultraviolet curable adhesive)
The following components were mixed to obtain an ultraviolet curable adhesive.
・3',4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (product name: CEL2021P, manufactured by Daicel Corporation): 70 parts by mass ・Neopentyl glycol diglycidyl ether (product name: EX-211, Nagasechem) (manufactured by Tex Corporation): 20 parts by mass 2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Corporation): 10 parts by mass / cationic polymerization initiator (trade name: CPI-100_50% solution, San-Apro Co., Ltd.): 4.5 parts by mass (substantially solid content 2.25 parts by mass)
・1,4-diethoxynaphthalene: 2 parts by mass

(Production of retardation material (B) with base film)
The first laminate (B) and the second laminate (B) are laminated such that the first retardation layer side and the second retardation layer side face each other via the ultraviolet curable adhesive prepared above. did. Next, the ultraviolet curable adhesive was cured by irradiation with ultraviolet rays to form an adhesive layer with a thickness of 1 μm, thereby producing a retardation material with a base film (B).
[Examples 8 to 14]
Optical laminates were produced in the same manner as Examples 1 to 7, except that the retardation material with a base film (B) was used instead of the retardation material with a base film (A). When the optical laminate was subjected to an impact resistance test and a bending test using the above-described procedure, the results were the same as those of Examples 1 to 7.

1 polarizing plate, 2 optical laminate, 10 polarizer, 11 mount with measurement film, 12 measurement film, 16 void, 17 mount with adhesive, 18 outer periphery, 20 protective film, 21 base layer, 22 easily adhesive layer, 30 Retardation material, 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 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 easily adhesive 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 easily adhesive 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%. The polarizing plate according to claim 1, wherein the thickness of the polarizer is 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 easily adhesive layer contains a urethane resin. The polarizing plate according to any one of claims 1 to 5, wherein the protective film and the polarizer are laminated with a bonding layer interposed therebetween. An optical laminate comprising the polarizing plate according to any one of claims 1 to 6, a retardation material, and an adhesive layer in this order. The polarizing plate includes the protective film on one side of the polarizer,
The optical laminate includes a retardation member on a side of the polarizer opposite to the protective film side,
The optical laminate according to claim 7, wherein the retardation body includes a liquid crystal hardening layer. A display device comprising the optical laminate according to claim 7 or 8.

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