TW202340770A - Polarizing plate - Google Patents

Abstract

An objective of the present invention is to provide a polarizing plate having good flexibility and good impact resistance. As a solution, provided is a polarizing plate comprising: a polarizer containing a polyvinyl alcohol-based resin and boron, and a protective film. The boron content of the polarizer is 2.8 mass% or more and 4.7 mass% or less. The protective film has a substrate layer and an easily adhesive layer laminated on the polarizer side of the substrate layer. The thickness of the base material layer is 30 [mu]m or less. The thickness of the easy-adhesion layer is 70 nm or more and 800 nm or less. The breaking elongation of the polarizing plate in both the absorption axis direction and the transmission axis direction at a temperature of 25 DEG C and a relative humidity of 55% is 4.0% or more and 14.0% or less.

Description

polarizing plate

The present invention relates to a polarizing plate, and in particular to an optical laminated body and a display device.

It is known that a polarizing plate is arranged on the viewing side of display devices such as liquid crystal display devices and organic EL display devices. Polarizing plates are generally protective films placed on one or both sides of a polarizer to protect the polarizer. In order to improve the adhesion between the protective film and the polarizer, an easy-adhesion layer is provided on the surface of the protective film (for example, Patent Document 1, etc.).

[Prior technical literature]

[Patent Document]

[Patent Document 1] Japanese Patent No. 6580769

In recent years, flexible display devices such as foldable ones have attracted much attention. Flexible display devices require the use of polarizing plates that can be bent repeatedly. Polarized light that can be bent repeatedly In order to obtain good bending properties, there is a tendency to reduce the overall thickness of the polarizing plate by reducing the thickness of the polarizing element and the protective film, thereby easily reducing the impact resistance of the polarizing plate.

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

The present invention provides the following polarizing plate, optical laminated body, and display device.

[1] A polarizing plate including a polarizer containing polyvinyl alcohol resin and boron, and a protective film, wherein:

The boron content of the aforementioned polarizer is 2.8 mass% or more and 4.7 mass% or less.

The protective film has a base material layer and an easy-adhesion layer laminated on the polarizer side of the base material layer,

The thickness of the aforementioned base material layer is 30 μm or less,

The thickness of the aforementioned easy-adhesive layer is not less than 70nm and not more than 800nm,

The elongation at break of the aforementioned polarizing plate in the absorption axis direction and the transmission axis direction at a temperature of 25°C and a relative humidity of 55% is both 4.0% and below 14.0%.

[2] The polarizing plate according to [1], wherein the thickness of the polarizing element is 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 material 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-based resin.

[6] The polarizing plate according to any one of [1] to [5], wherein the protective film and the polarizing element are laminated via an adhesion layer.

[7] An optical laminate including the polarizing plate, the retardation body, and the adhesive layer described in any one of [1] to [6] in this order.

[8] The optical laminate according to [7], wherein the polarizing plate is provided with the protective film on one side of the polarizer,

The optical laminated body includes a retardation body on a side of the polarizer opposite to the protective film side,

The retardation body includes a liquid crystal hardened layer.

[9] A display device including the optical laminate according to [7] or [8].

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

1:Polarizing plate

2: Optical laminated body

10:Polarizer

11: Cardboard with measuring film

12:Measurement film

16: Gap part

17: With adhesive cardboard

18:Periphery

20:Protective film

21:Substrate layer

22: Easy to adhere layer

30: Phase difference body

31: 1st phase difference layer

32: 2nd phase difference layer

33: The third laminating layer

41: The first laminating layer (laminated layer)

42: 2nd laminating layer

FIG. 1 is a schematic cross-sectional view of a polarizing plate according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing an optical laminate according to an embodiment of the present invention.

Figure 3 is a schematic top view of an adhesive cardboard with voids used for measuring the puncture elastic modulus.

Figure 4(a) shows a schematic perspective view of the main part of the adhesive-attached paperboard shown in Figure 3 when the film is adhered to the film, and (b) is a schematic view of the adhesive-attached paperboard shown in Figure 3 when the film is adhered to the film. Picture of the upper part behind the membrane.

Figure 5 schematically shows a cross-sectional view when a needle is pierced after the adhesive cardboard shown in Figure 3 is attached to the measurement film.

6 is a cross-sectional view schematically showing the measurement of the puncture elastic modulus, and (a) and (b) show the state in which the measurement film is deformed by puncturing the measurement film with a needle.

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

(Polarizing plate)

FIG. 1 schematically shows a cross-sectional view of a polarizing plate according to an embodiment of the present invention. The polarizing plate 1 of this embodiment includes a polarizing element 10 containing polyvinyl alcohol-based resin and boron, and a protective film 20 . The polarizing plate 1 may be a linear polarizing plate. The protective film 20 has a base material layer 21 and an easy-adhesion 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 on only one side of the polarizer 10 , or may have the protective film 20 on both sides of the polarizer 10 . When the protective film 20 is provided on only one side of the polarizer 10 , the protective film 20 is preferably disposed on the recognition side of the polarizer 10 .

As shown in FIG. 1 , the polarizer 1 and the protective film 20 are preferably laminated via the first bonding layer 41 (bonding layer). At this time, the easy-adhesion layer 22 of the polarizer 10 and the protective film 20 is preferably in direct contact with the first bonding layer 41 . The first laminating layer 41 may be an adhesive layer or an 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 polarizing plate 1, the absorption axis direction The elongation at break is usually greater than the elongation at break in the direction of the penetration axis, and can be more than 1.2 times, more than 1.4 times, or more than 1.5 times the elongation at break in the direction of the penetration axis.

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, or may be 8.0% or more and 11.0% or less. The above-mentioned elongation at break in the direction of the transmission axis of the polarizing plates 1 and 2 may be 4.2% or more and 12.0% or less, 4.5% or more and 10.0% or less, 4.7% or more and 9.0% or less, or 5.0% or more and 8.0% or less. By setting the elongation at break of the polarizing plate 1 within the above range, the polarizing plate 1 can easily have both good bending properties and good impact resistance. The above-mentioned elongation at break 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 material layer 21 , the type and thickness of the easy-adhesive layer 22 , etc. The above-mentioned elongation at break can be measured by the method described in the Examples described below.

The polarizing plate 1 has a breaking elongation within the above range and, as described later, has a polarizing element 10 with a boron content of 2.8 mass % or more and 4.7 mass % or less, and a base material layer 21 with a thickness of 30 μm or less and a thickness of 30 μm or less. It is the protective film 20 of the easy-adhesion layer 22 with a thickness of 70 nm or more and 800 nm or less. In this way, the polarizing plate 1 can have both good flexibility and good impact resistance.

In this specification, as described in the examples described below, good bendability can be achieved by cracks occurring in the bending axis portion of the polarizing plate 1 during the bending test of the polarizing plate 1 , peeling between the layers of the polarizing plate 1 , etc. evaluate. When the polarizing plate 1 has the protective film 20 on only one side of the polarizer 10, it is preferable to perform the above-mentioned bending with the protective film 20 side facing inward.

As described in the examples described below, good impact resistance can be evaluated by cracks, scratches, etc. generated in the polarizer 10 in an impact resistance test using an evaluation pen.

Even when the polarizing plate 1 of this embodiment is repeatedly bent, the occurrence of peeling between the polarizer 10 and the protective film 20 and the occurrence of cracks in the polarizing plate 1 can be suppressed in the bending axis portion, so it is suitable for use in various applications. Flexible display device. The bending radius of the polarizing plate 1 is not limited. The bending of the polarizing plate 1 includes a refraction type in which the refraction angle of the inner surface is greater than 0° and less than 180°, and a folding type in which the bending radius of the inner surface is close to zero, or the refraction angle of the inner surface is 0°.

In the polarizing plate 1, the adhesion between the polarizing element 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, 3N or more and 15N or less, and may also be 6N or more and 12N or less. When the adhesion force of the polarizing plate 1 falls within the above range, it becomes easy to obtain the polarizing plate 1 in which peeling between the layers of the polarizing plate 1 due to bending is suppressed. The above-mentioned adhesion force can be adjusted by the combination of the type of the base material layer 21 and the type of the easy-adhesive layer 22 included in the protective film 20, the thickness of the easy-adhesive layer 22, and the like.

In plan view, the polarizing plate 1 may have a square shape, for example, preferably a square shape with long sides and short sides, and more preferably a rectangular shape. The entire polarizing plate 1 or one or more layers among the layers constituting the polarizing plate 1 may be rounded at the corners, notched at the ends, or perforated.

The thickness of the polarizing plate 1 is not particularly limited as long as it has good flexibility and good 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. By setting the thickness of the polarizing plate 1 within the above range, the polarizing plate 1 can be made thinner and the polarizing plate 1 can be easily bent. For example, the thickness of the polarizing plate 1 shown in FIG. 1 means the total thickness of the polarizer 10 and the protective film 20 constituting the polarizing plate 1, and the total thickness of the first bonding layer 41 that joins them to each other.

The polarizing plate 1 may be a polarizing plate in which an adhesive layer is laminated on a single surface of the polarizing plate 1 and the adhesive layer is attached thereto. The polarizing plate with the adhesive layer can also be further placed on the side of the adhesive layer opposite to the polarizing plate 1 side. It has a release film that can be peeled off from the adhesive layer. When the polarizing plate 1 shown in FIG. 1 only has the protective film 20 on one side, it is preferably provided with an adhesive layer on the side of the polarizer 10 .

(Optical laminated body)

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

The retardation body 30 contained in the optical laminate 2 may include a liquid crystal cured layer. The phase difference body 30 is preferably laminated on one side of the polarizer 10. When there is only one side of the polarizer 10 with the protective film 20, for example, as shown in FIG. 2, the polarizer 10 can be placed on the side opposite to the protective film 20 side. A phase difference body 30 is provided. At this time, it is preferable that the polarizer 10 and the retardation body 30 are laminated via the second bonding layer 42 . The second bonding layer 42 can be directly in contact with the polarizer 10 and the retardation body 30 including the retardation layer described below. The second bonding layer 42 is an adhesive layer or an adhesive layer, preferably an adhesive layer.

The retardation body 30 includes one or more retardation layers, and the retardation layer may include a liquid crystal hardened layer. When the retardation body 30 includes two or more retardation layers, it is preferable that the two or more retardation layers are laminated with a lamination layer interposed therebetween. For example, as shown in FIG. 2 , the retardation body 30 may be a laminated body in which the first retardation layer 31 , the third bonding layer 33 , and the second retardation layer 32 are laminated in this order. At this time, at least one of the first retardation layer 31 and the second retardation layer 32 preferably includes a liquid crystal hardened layer, and both of them may include a liquid crystal hardened layer. The third bonding layer 33 is an adhesive layer or an adhesive layer, preferably an adhesive layer.

The first retardation layer 31 may include an alignment layer and a liquid crystal hardened layer. The first retardation layer 31 may have an overcoat layer that protects the surface of the liquid crystal hardened layer or 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 hardened layer. The second retardation layer 32 may have an overcoat layer that protects the surface of the liquid crystal hardened 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 series of the first retardation layer 31 and the second retardation layer 32 is as follows: [i] Giving a phase difference of λ/4 A combination of a retardation layer (λ/4 layer) and a retardation layer giving a phase difference of λ/2 (λ/2 layer), or [ii] a retardation layer giving a phase difference of λ/4 (λ/4 layer) ) and the combination of positive C layer, etc. 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 λ/4 layer with reverse wavelength dispersion. When the retardation body 30 includes a 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 may be 45°±10°. Thereby, the optical laminated body 2 has an anti-reflection function and can function as a circularly polarizing plate.

The thickness of the optical laminated body 2 is not particularly limited as long as it has good flexibility and good 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. By having the thickness of the optical laminated body 2 within the above range, the optical laminated body 2 can be further thinned and the optical laminated body 2 can be easily bent. For example, the thickness of the optical laminated body 2 shown in FIG. 2 means the total thickness of the polarizer 10, the protective film 20, and the retardation element 30 constituting the optical laminated body 2, and the first bonding process for joining these. The total thickness of the layer 41 and the second bonding layer 42.

Hereinafter, each layer constituting the polarizing plate 1 and the optical laminate 2 will be described in detail.

(Polarized parts)

Polarizers have the function of selectively transmitting linearly polarized light from non-polarized light such as natural light. The polarizer contains polyvinyl alcohol-based resin and boron. The polarizer is preferably an extended film adsorbed with a dichroic pigment. When a dichroic pigment is dispersed in a polymer chain (polyvinyl alcohol-based resin chain) that is anisotropic due to elongation, if it is colored when viewed from a certain direction, it will be almost colorless when viewed from a direction perpendicular to it.

In addition to adsorbing and stretching the dichroic pigment on a monomer polyvinyl alcohol-based resin film (hereinafter also referred to as "PVA resin film") to obtain a polarizing element, the stretched film system with adsorbed dichroic pigments can also be used, for example, in Japan As described in Japanese Patent Application Publication No. 2012-73563, a polyvinyl alcohol-based resin layer (hereinafter also referred to as "PVA resin layer") is provided on a base film (thermoplastic resin film) such as an ester-based thermoplastic resin film, and the PVA resin is The layer is extended with the substrate and the dichroic pigment is then adsorbed/aligned to create the polarizer. The polarizer obtained by such a method is also referred to as "extension layer" below. In addition, the general method used to manufacture the extension layer is described below. When the polarizer is an extended layer, since it is produced using an appropriate base film (thermoplastic resin film) as described above, the polarizer belonging to the extended layer is supported by the base film (thermoplastic resin film). The polarizing plate may be configured such that the base film supporting the polarizer is used as a protective layer of the polarizer.

The boron content of the polarizer included in the polarizing plate is 2.8 mass% or more and 4.7 mass% or less. The boron content of the polarizer may be 3.0 mass% or more and 4.5 mass% or less, or may be 3.2 mass% or more and 4.3 mass% or less. By setting the boron content of the polarizer within the above range, the occurrence of cracks accompanying bending can be suppressed, and a polarizing plate with good impact resistance can be easily obtained. Polarizers with a boron content within the above range can inhibit shrinkage in hot and humid environments.

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. Boron in polarizers is considered to exist in a free state of boric acid (H ₃ BO ₃ ) or in a state in which boron forms a cross-linked structure with units of polyvinyl alcohol-based resin. In this specification, the boron content includes the amount of the boron atom (B) itself that exists in the state of a compound as described above. As will be described later, the boron content of the polarizer can be adjusted by the amount of boric acid used in manufacturing the polarizer or the boric acid treatment conditions.

The shrinkage force in the absorption axis direction of the polarizer is preferably 2.4N/2mm or less, more preferably 2.1N/2mm or less. When the shrinkage force in the absorption axis direction of the polarizer is within the above range, the occurrence of cracks accompanying bending can be suppressed, and a polarizing plate with good impact resistance can be easily obtained. The shrinkage force in the absorption axis direction of polarizers is usually above 1.3N/2mm. As described in the examples described below, the shrinkage force in the absorption axis direction of the polarizer was measured for the polarizer maintained at a temperature of 80° C. for 4 hours. The shrinkage force in the direction of the absorption axis of the polarizer can be adjusted by the boron content, the type and amount of the dichroic pigment used in the polarizer, the extension ratio, etc.

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, may be 9 μm or less, or may be 8 μm or less. By reducing the thickness of the polarizing element, the polarizing plate can be made thinner, and it becomes easier to realize a polarizing plate with 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 of the PVA resin film (embryonic membrane) before stretching or the PVA resin layer before stretching and the stretching ratio. When the polarizer is an extension layer adsorbed with dichroic pigments, the thickness and extension ratio of the PVA resin layer formed on the base film can be adjusted.

The polarizer can be manufactured through the following steps: the step of uniaxially stretching the PVA resin film; the step of dyeing the PVA resin film with dichroic pigments such as iodine and adsorbing the dichroic pigment; and the step of adsorbing the dichroic pigment. A step of treating the pigmented PVA resin film with a boric acid aqueous solution; and a step of washing with water after being treated with the boric acid aqueous solution. The PVA resin film before uniaxial stretching can It is easy to obtain it from the market, and as described later, polyvinyl acetate-based resin can be produced by a conventional method, saponified to produce polyvinyl alcohol-based resin, and the polyvinyl alcohol-based resin can be formed into a film. A film can be formed at the stage of polyvinyl acetate resin, and the polyvinyl acetate resin contained in the film can be saponified.

When the polarizing element is an extended layer adsorbed with dichroic pigments, the polarizing element can usually be manufactured through the following steps: coating a coating liquid containing polyvinyl alcohol resin on the base film, and forming it on the base film. The step of forming a laminated film with a PVA resin layer (hereinafter also referred to as "PVA laminated film"); the step of uniaxially stretching the obtained PVA laminated film; and the uniaxially stretched PVA by dyeing it with a dichroic pigment The step of adsorbing the dichroic pigment on the PVA resin layer of the laminated film to make a polarizing element; the step of treating the PVA resin layer with the dichroic pigment adsorbed on the PVA resin layer with a boric acid aqueous solution; and, using the boric acid aqueous solution After treatment, wash with water. The base film used to form the polarizer can also be used as a protective layer on the polarizer. If necessary, the base film can be peeled off and removed from the polarizer. Examples of the material and thickness of the base film include the materials and thickness of the base layer constituting the protective film, which will be described later.

Polyvinyl alcohol-based resin is obtained by saponifying polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers copolymerizable therewith can also be used. Examples of other monosystems that can be copolymerized with vinyl acetate are: unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated styrene compounds, and (meth)acrylic acid amide compounds with ammonium groups. wait. In this specification, (meth)acrylic acid means at least one of acrylic acid and methacrylic acid. The same applies to the (meth)acrylyl group and the like.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 mol% or more and 100 mol% or less, preferably 98 mol% or more. Polyvinyl alcohol-based resin can be modified, and aldehyde-modified polyvinyl formaldehyde, polyvinyl acetal, etc. can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually from 1,000 to 10,000, preferably from 1,500 to 5,000.

Dichroic pigments can use iodine and organic dyes, but iodine is preferably used. When using iodine as a dichroic dye, a polyvinyl alcohol-based resin film or a PVA laminated film containing a base film and a PVA resin layer is usually immersed in a dyeing bath containing iodine and iodide, and the polyvinyl alcohol-based resin film is dyed with iodine. resin. Examples of the iodide series include potassium iodide, zinc iodide, etc., but potassium iodide is preferred. The iodine content in this dyeing bath can be 0.003 to 1 part by mass per 100 parts by mass of water. The iodide content may be 0.15 to 20 parts by mass per 100 parts by mass of water. Furthermore, the temperature of the dyeing bath can be about 10 to 45°C.

In particular, in the step of treating a PVA resin film to which iodine is adsorbed as a dichroic dye or a PVA laminated film including a PVA resin layer and a base film with a boric acid aqueous solution, the PVA to which the dichroic dye is adsorbed is usually The resin film or PVA laminated film is immersed in a boric acid aqueous 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. Cross-linking agents such as glyoxal and glutaraldehyde can also be used with boron compounds. The solvent of the boric acid aqueous solution can be water, but 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 adsorbed with the dichroic pigment or the PVA resin layer with a boric acid aqueous solution. For example, the boron content of the polarizer can be adjusted by changing the concentration/amount of boric acid in the boric acid aqueous solution, changing the temperature of the boric acid aqueous solution, and changing the immersion time in the boric acid aqueous solution. Appropriate preliminary experiments can also be carried out to derive the conditions for the polarizer to have the desired boron content. In order to adjust the boron of the polarizer content, it is preferable to set the concentration of boric acid in the boric acid aqueous solution to 2.0 to 6.5 parts by mass per 100 parts by mass of water, and appropriately adjust the immersion time in the cross-linking bath; more preferably, the concentration of boric acid is set to 2.0 to 6.5 parts by mass per 100 parts by mass of water. The mass parts of water are 3.0 to 6.0 mass parts, and the immersion time in the cross-linking bath is appropriately adjusted.

The boric acid aqueous solution may further contain iodide. By adding iodide, the in-plane polarization performance of the obtained polarizer can be made more uniform. Examples of the iodide compound 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 mass per 100 parts by mass of water.

The temperature of the boric acid aqueous solution (crosslinking bath) can usually be set to 40 to 80°C, preferably 50 to 70°C. When the temperature of the cross-linking bath is too low, the cross-linking reaction between the units of the polyvinyl alcohol-based resin and boron in the PVA resin film or PVA resin layer tends to be insufficient. On the other hand, when the temperature of the cross-linking bath is too high, the PVA resin film or the PVA laminated film will be easily cracked in the cross-linking bath, and the processing stability will be significantly reduced. The immersion time in the cross-linking bath is usually 10 to 600 seconds, preferably 60 to 420 seconds, more preferably 90 to 300 seconds.

The uniaxial stretching of PVA resin film or PVA laminated film can be carried out before dyeing, during dyeing, or in the step of treating with boric acid aqueous solution after dyeing, or in a plurality of these stages. Perform uniaxial extension respectively. A PVA resin film or a PVA laminated film can be uniaxially stretched in the MD direction (film conveyance direction). In this case, uniaxial stretching can be performed between rollers with different peripheral speeds, or a hot roller can be used for uniaxial stretching. Furthermore, the PVA resin film or the PVA laminated film can be uniaxially stretched in the TD direction (the direction perpendicular to the film conveyance direction). In this case, a so-called tenter method can be used. Furthermore, 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 swollen state using a solvent. In order to express the performance of the polarizer, the extension ratio is 3.0 times or more, preferably 3.5 times or more, and particularly preferably 4.0 times or more. The upper limit of the stretch ratio is not particularly limited, but from the viewpoint of suppressing cracking, etc., it is preferably 8.0 times or less.

(protective film)

The protective film is placed 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 material layer and an easy-adhesion layer. The base material layer and the easy-adhesive layer are usually directly connected. The easy-adhesion layer is usually provided on one side of the base material layer, but it can also 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 210g/mm or more and 550g/mm or less. The puncture elastic modulus E of the protective film can be more than 250g/mm and less than 500g/mm, it can be more than 300g/mm and less than 450g/mm, or it can be more than 320g/mm and less than 420g/mm. When the puncture elastic modulus E of the protective film is within the above range, it becomes easy to achieve the breaking elongation of the polarizing plate in the above range, and it becomes easy to obtain a polarizing plate that has both good flexibility and good impact resistance. 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 material layer, etc.

0.5R之針以0.33cm/秒之速度，對於位在空隙部16的該保護膜(測定膜12)之面垂直地穿刺(圖5及圖6)，並將產生破裂時所測定之由該保護膜(測定膜12)在穿刺方向撓曲所造成之位移量作為應變量S[mm]，將施加於該保護膜(測定膜 12)之應力作為F[g]時，將藉由下式(1)所算出之物性值作為應力F與應變S之間的比率常數(應力F/應變S)。 The method of measuring the puncture elastic modulus E of the protective film will be described with reference to FIGS. 3 to 6 . In this specification, the puncture elastic modulus E is measured using a measurement sample (Fig. 4) as described in the examples described later. This measurement sample is obtained by cutting out a square of 30 mm×30 mm in the center and forming a gap 16. For those with a protective film (measurement film 12) attached to the adhesive cardboard 17 (Figure 3), in an environment with a temperature of 25°C and a relative humidity of 55%, the diameter of the front end is 1 mm.

A 0.5R needle vertically punctures the surface of the protective film (measurement film 12) located in the gap 16 at a speed of 0.33cm/second (Fig. 5 and Fig. 6), and the measured value when the rupture occurs is determined by the When the amount of displacement caused by the deflection of the protective film (measurement film 12) in the puncture direction is taken as the strain amount S [mm], and the stress applied to the protective film (measurement film 12) is taken as F [g], the following formula is used (1) The calculated physical property values are used as the ratio constant between stress F and strain S (stress F/strain S).

Puncture elastic modulus E[g/mm]=F[g]/S[mm] (1)

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 testing machine, the stress applied to the measurement film 12 when rupture occurs and the amount of strain generated in the measurement film 12 until then can be measured. In addition, the cracks that occur in the measurement film 12 when the jig is squeezed and punctured include the case where a through hole is formed in the measurement film 12 due to the tip of the jig.

For example, a compression testing machine equipped with a force measuring device explains the main part of the method of measuring the puncture elastic modulus E when using a puncture testing machine "NDG5" manufactured by Kato Technology Co., Ltd. FIG. 3 is a schematic plan view of the adhesive cardboard 17 having the gaps 16 for obtaining the puncture elastic modulus E of the protective film. As shown in FIG. 3 , the adhesive cardboard 17 has a 30 mm × 30 mm square portion (gap portion 16 ) in the center, and this portion serves as a protective film to be adhered for measurement (hereinafter referred to as "measurement"). membrane 12") part.

Figure 4 is a schematic diagram showing the main parts when the adhesive cardboard 17 is attached to the measurement film 12. Figure 4 (a) is a perspective view when the adhesive cardboard 17 is attached to the measurement film 12. Figure 4 (b) It is a top view (direction A in Figure 4(a)) of the cardboard 11 with the measurement film after the adhesive cardboard 17 is attached to the measurement film 12. The dotted line in FIG. 4(b) indicates the outer periphery 18 of the gap 16. The position M located in the center of the gap 16 and pierced by the needle N is the intersection of two straight lines connecting points (R and R') facing each other in the oblique direction of the outer periphery 18 of the gap 16. Fig. 5 schematically shows a cross-sectional view along I-I' in the cardboard 11 with a measuring film shown in Fig. 4 (before needle N pierces).

The needle N is inserted into the central portion M of the measurement film 12 (for example, the intersection of two diagonal lines connecting R and R' at the vertex of the outer periphery 18 of the gap portion in Fig. 4(b)). During this puncture, the correlation between the stress F [g] applied to the needle N and the amount of strain S [mm] caused by the deflection of the measurement film 12 in the puncture direction was determined. From the stress F when the rupture of the measurement film 12 occurs, [g] and the strain amount S [mm] are used to calculate the puncture elastic modulus E through the above formula (1). When the puncture elastic modulus E is determined, rupture may occur in a state where the measurement film 12 is deformed (a rupture may occur in the state in FIG. 6(a) ), or in a state where the measurement film 12 is further deformed. In the case of rupture (the situation in which rupture occurs in the state of Figure 6(b)), the puncture elastic modulus E in this specification is calculated from the applied stress and strain S in the puncture testing machine. The strain S can be as shown in the figure The S that causes rupture in the state of Figure 6(a) may also be the S that causes rupture in the state of Figure 6(b). Furthermore, when the measurement film 12 cracks, the applied stress changes from an upward tendency to a downward tendency. Therefore, it can be understood that the crack occurs at this change point.

In the adhesive-attached cardboard 7, the adhesive used to fix the measuring film 12 can prevent the measuring film 12 from even being partially peeled off from the measuring film-attached cardboard 11 during the measurement of the elastic modulus E. There are no special restrictions. In order to find out the adhesive of the adhesive-coated cardboard 17 used in the determination of the puncture elastic modulus E, appropriate preliminary tests may also be performed.

The thickness of the protective film 20 is not less than 8 μm and not more than 31 μm, preferably not less than 10 μm and not more than 30 μm, and may be not less than 15 μm and not more than 25 μm. When the thickness of the protective film is reduced, the polarizing plate can be made thinner and the polarizing plate can be easily bent.

(Substrate layer)

The base material layer constituting the protective film imparts mechanical strength to the protective film and has the function of 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, may be 10 μm or more and 29 μm or less, or may be 15 μm or more and 25 μm or less. When the thickness of the base material layer is reduced, the polarizing plate can be made thinner and the polarizing plate can be easily bent.

For example, a resin film excellent in transparency, mechanical strength, thermal stability, moisture resistance, isotropy, stretchability, etc. can be used for the base material layer. The resin film may also be a thermoplastic resin film. Specific examples of such resins include: cellulose-based resins such as cellulose triacetate; polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate; polyether-based resins; polyester-based resins; Resin; polycarbonate resin; polyamide resin such as nylon and aromatic polyamide; polyimide resin; polyolefin resin such as polyethylene, polypropylene, ethylene/propylene copolymer; with ring system and Norbornene-structured cyclic polyolefin-based resins (also known as norbornene-based resins); (meth)acrylic resins; polyarylate-based resins; polystyrene-based resins; polyvinyl alcohol-based resins, and the like etc. mixture. The resin film is preferably a uniaxially stretched film or a biaxially stretched film.

The base layer preferably uses a resin film composed of (meth)acrylic resin. The (meth)acrylic resin is preferably polymethylmethacrylate resin. The resin film composed of (meth)acrylic resin is preferably stretched. The resin film composed of (meth)acrylic resin is preferably small in thickness, particularly 30 μm or less (preferably 25 μm or less), because it can have a moderate puncture elastic modulus E.

(Easy adhesive layer)

The easy-adhesion layer constituting the protective film can improve the adhesion to the first bonding layer used to bond the protective film and the polarizer, and can also improve the adhesion between the protective film and the polarizer in the polarizing plate. therefore, The easy-adhesion layer is usually provided on the surface of the base material layer so as to constitute the surface of the polarizer side of the protective film.

The thickness of the easy-adhesion layer is between 70nm and 800nm. The thickness of the easy-adhesion layer may be 80 nm to 750 nm, 100 nm to 700 nm, 200 nm to 650 nm, 280 nm to 600 nm, or 290 nm to 600 nm. When the thickness of the easy-adhesion layer is within the above range, the adhesion between the protective film and the polarizer can be improved. Furthermore, it becomes easier to obtain a polarizing plate that is less likely to cause interlayer delamination due to bending.

The easy-adhesion layer contains a resin component, and may further contain organic or inorganic filler additives, and the like. The resin component contained in the easy-adhesive layer can be cross-linked. Examples of the resin component include urethane resin, (meth)acrylic resin, polyester resin, and the like. The resin component contained in the easy-adhesion layer is preferably a urethane resin, more preferably a polyester urethane resin or a polyether urethane resin. The resin component can be used together with polyester urethane resin and polyether urethane resin. The polyester urethane resin is a urethane resin having an ester bond in the main chain of the molecule. The polyether urethane resin is a urethane resin having an ether bond in the main chain of the molecule.

Inorganic fillers include: silica, titanium dioxide, alumina, zirconia and other inorganic acid compounds; calcium carbonate, talc, clay, fired kaolin, fired calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate , calcium phosphate, etc. Examples of organic fillers include silicone resin, fluororesin, acrylic resin, and the like. Among these, silicon oxide is preferred, and colloidal silicon oxide is more preferred.

The easily adhesive layer can be formed using an easily adhesive composition. The easy-adhesion composition may include resin components, fillers, cross-linking agents, alkali components, solvents, etc. The resin components are preferably dissolved or dispersed composition based on solvents. The easy-adhesion composition may include monomers used to form the resin component and a polymerization initiator to replace the resin component.

唑啉基、環氧基、或碳二亞胺基等的交聯劑。 The crosslinking agent only needs to be one capable of reacting with the crosslinkable functional group of the resin component. When the resin component is urethane resin having cross-linkable functional groups such as carboxyl groups, it is possible to use urethane resin containing amine groups,

Cross-linking agents such as oxazoline-based, epoxy-based, or carbodiimide-based.

Examples of the base component include ammonia, amine compounds (primary amine, secondary amine, tertiary amine, etc.), hydrazine compounds, imidazole compounds, or imidazoline compounds.

Examples of the solvent system include water or water-soluble solvents. Examples of water-soluble solvent series include: methanol, ethanol, isopropyl alcohol, acetone, tetrahydrofuran, N-methylpyrrolidone, dimethylserioxide, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, etc. The preferred solvent is water.

The easily-adhesive layer can be formed by applying the easily-adhesive composition to the surface of the base material layer that faces the polarizer and drying it. Methods for applying the easy-adhesion composition include: die-slit coater, notch wheel coater, reverse roller coater, gravure coater, rod coater, wire bar coater, and doctor blade Coating methods such as applicators and air knife applicators. The coated easy-adhesion 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 used to form a resin component, it is only necessary to dry and harden the applied easy-adhesive composition, and then set a maturation step as required to form an easy-adhesive layer. .

(Phase difference body)

The retardation system includes a liquid crystal hardened layer, a layer that imparts retardation to the polarizing plate. The retardation body preferably has one or more retardation layers including a liquid crystal hardened layer. When the retardation body contains more than two retardation layers, as long as at least one retardation layer contains a liquid crystal hardened layer, the remaining retardation The layer system may be formed from stretched film. When the retardation body includes two or more retardation layers, the retardation body preferably has a bonding layer for bonding these layers.

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

(Phase difference layer (first phase difference layer, second phase difference layer))

The retardation layer (first retardation layer, second retardation layer) contained in the retardation body may be formed of the resin film exemplified as the material of the base material layer constituting the protective film, or may be formed of a liquid crystal cured layer. The liquid crystal hardened layer is preferably a layer obtained by polymerization and hardening of a polymerizable liquid crystal compound. The first retardation layer and the second retardation layer are as described above. In addition to the liquid crystal cured layer, they may also include an alignment layer, a base film, an overcoat layer, and the like.

When the liquid crystal cured layer is a layer obtained by polymerization and curing of a polymerizable liquid crystal compound, it can be formed by applying a composition containing a polymerizable liquid crystal compound to a base film and curing the composition. An alignment layer can also be formed between the base film and the coating layer. Examples of the material and thickness of the base film include the materials and thickness of the base layer constituting the protective film.

The 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 hardened layer is not particularly limited, and rod-shaped liquid crystal compounds, disk-shaped liquid crystal compounds, and mixtures thereof can be used. The cured material layer formed by polymerizing the polymerizable liquid crystal compound is cured in a state in which the polymerizable liquid crystal compound is aligned in a suitable direction to exhibit a phase difference. When the rod-shaped polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the plane direction of the optical layered body, the optical axis of the polymerizable liquid crystal compound coincides with the long axis direction of the polymerizable liquid crystal compound. When the disk-shaped polymerizable liquid crystal compound is aligned, The optical axis of the polymerizable liquid crystal compound exists in a direction orthogonal to the disk surface of the polymerizable liquid crystal compound. Examples of rod-shaped polymerizable liquid crystal compounds that can be suitably used include those described in Japanese Patent Application Publication No. 11-513019 (claim 1, etc.). Disc-shaped polymerizable liquid crystal compounds can be suitably used: Japanese Patent Application Laid-Open No. 2007-108732 (paragraphs [0020] to [0067], etc.), Japanese Patent Application Laid-Open No. 2010-244038 (paragraphs [0013] to [0108] ] paragraph, etc.).

The polymerizable group contained in the polymerizable liquid crystal compound means a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. The photopolymerizable group means a group that can participate in the polymerization reaction through active radicals, acids, etc. generated from the photopolymerization initiator. Examples of polymerizable groups include: vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, (meth)acryloxy, oxirane, and oxetane Alkyl, styryl, allyl, etc. Among them, a (meth)acryloxy group, an vinyloxy group, an oxirane group and an oxetanyl group are preferred, and an acryloxy group is more preferred. The liquid crystallinity of the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a liquid crystal. When the thermotropic liquid crystal is classified according to the degree of order, it may be a nematic liquid crystal or a smectic liquid crystal. When two or more types of polymerizable liquid crystal compounds are used together to form a hardened material layer of a polymerizable liquid crystal compound, it is preferable that at least one type has two or more polymerizable groups in the molecule.

The liquid crystal cured layer is a composition for forming a liquid crystal cured layer containing a polymerizable liquid crystal compound, a solvent, and various additives as required. The liquid crystal cured layer is coated on the alignment layer described later to form a coating film, and the coating film is cured (hardened). ) to form a layer in which the polymerizable liquid crystal compound is polymerized and hardened. Alternatively, it can be formed by applying the above composition on a base film to form a coating film, extending the coating film together with the base film, and hardening the coating film. In addition to the above-mentioned polymerizable liquid crystal compound and solvent, the above composition system may also include a polymerization initiator, a reactive additive, a leveling agent, a polymer Inhibitors etc. As the polymerizable liquid crystal compound, solvent, polymerization initiator, reactive additive, leveling agent, polymerization inhibitor, etc., those known in the art can be appropriately used.

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

The alignment layer system 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 vertically with respect to the plane direction of the optical laminate, or it may be a horizontal alignment layer in which the molecular axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the plane direction of the laminate. The layer may also be a tilt alignment layer in which the molecular axis of the polymerizable liquid crystal compound is tilt-aligned with respect to the plane direction of the optical laminate.

The alignment layer preferably has solvent resistance that does not dissolve when a composition for forming a liquid crystal cured layer containing a polymerizable liquid crystal compound is applied, and heat resistance to heat treatment for removing the solvent and alignment of the polymerizable liquid crystal compound. By. Examples of the alignment layer system include: an alignment polymer layer formed of an alignment polymer, a photo-alignment polymer layer formed of a photo-alignment polymer, a layer having an uneven pattern formed by rubbing treatment, etc. on the surface of the layer, plural A groove (groove) groove alignment layer, etc.

(Laying layer (1st laminating layer, 2nd laminating layer, 3rd laminating layer))

The bonding layer (the first bonding layer, the second bonding layer, and the third bonding layer) is an adhesive layer or an adhesive layer.

The adhesive layer is a layer formed using an adhesive. Adhesives that exhibit adhesion by attaching themselves to the object to be adhered are also known as so-called pressure sensitive adhesives. As the adhesive, a conventional adhesive having excellent optical transparency can be used. sticky As the adhesive system, for example, an adhesive containing a base polymer such as an acrylic polymer, a urethane polymer, a polysiloxane polymer, or a polyvinyl ether can be used. Furthermore, the adhesive may be an active energy ray-hardening adhesive, a thermosetting adhesive, or the like. Among these, an adhesive using an acrylic resin as a base polymer that is excellent in transparency, adhesive force, re-peelability (reworkability), weather resistance, heat resistance, etc. is preferred. The adhesive layer is preferably composed of an adhesive containing (meth)acrylic resin, a cross-linking 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, usually is 300 μm or less, may be 250 μm or less, may be 100 μm or less, and may be less than 50 μm.

The adhesive layer system can be formed using an adhesive composition. The adhesive composition used to form the adhesive layer is an adhesive other than a pressure-sensitive adhesive (adhesive), and examples thereof include water-based adhesives and active energy ray-hardening 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 methods such as using a hot air dryer or an infrared dryer can be used.

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 light, visible light, electron rays, and X-rays. By using solvent-free active energy ray-curable adhesive, the adhesion between layers can be improved.

In order to exhibit good adhesion, the active energy ray curable adhesive preferably contains any one or two of a cationic polymerizable curable compound and a radical polymerizable curable compound. The active energy ray curable adhesive may further contain an agent for making the above curable A cationic polymerization initiator such as a photocationic polymerization initiator or a radical polymerization initiator that starts the hardening reaction of the compound.

The thickness of the adhesive layer is preferably 0.1 μm or more and may be 0.5 μm or more. Furthermore, the thickness is preferably 10 μm or less and may be 5 μm or less.

(adhesive layer)

The adhesive layer that the polarizing plate with an adhesive layer has and the adhesive layer that the optical laminate 2 can have can use the above-mentioned ones.

(peeling film)

The polarizing plate with the adhesive layer may have a release film, and the optical laminate 2 may have a release film, and may include 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 above-mentioned base material layer constituting the protective film. The release treatment layer only needs to be a conventional release treatment layer, and examples thereof include a layer formed by applying a release agent such as a fluorine compound and a polysiloxy compound to a base film.

(display device)

The polarizing plate and optical laminate with an adhesive layer can be used in a display device or a flexible display device. The display device may be composed of a polarizing plate or an optical laminate including a display element and an adhesive layer laminated on the recognition side of the display element. The polarizing plate and optical lamination system with adhesive layer can be bonded to the display element through its adhesive layer. A polarizing plate having a protective film only on one side of the polarizer with an adhesive layer and/or the polarizer included in the optical laminate, and the polarizer with the adhesive layer and the optical laminate are arranged on the viewing side of the display element When , it is preferable that the protective film is located closer to the identification side than the polarizer. The display device is not particularly limited, and examples thereof include organic EL display devices, inorganic EL display devices, liquid crystal display devices, and electroluminescence display devices. and other image display devices. The display device may have touchpad functionality. The polarizing plate and the optical laminate with the adhesive layer can be suitably used in a flexible display device having flexibility such as bending or bending.

The display device can be used as mobile devices such as smartphones and tablets, televisions, digital photo frames, electronic signboards, measuring instruments, office equipment, medical equipment, electronic computers, etc. It is particularly suitable for installation in applications where further requirements are required in the future. Miniaturized display device for mobile devices.

[Example]

The following examples and comparative examples will illustrate the present invention in more detail, but the present invention is not limited to these examples.

<Production of polarizer>

(Production of polarizer a)

Prepare a polyvinyl alcohol-based resin film with a thickness of 20 μm, a polymerization degree of 2400, and a saponification degree of 99% or more. This polyvinyl alcohol-based resin film was uniaxially stretched on a hot roller at a stretching ratio of 4.1 times while maintaining the tension, and was heated at 28° C. containing 0.05 parts by mass of iodine and 5 parts by mass of potassium iodide per 100 parts by mass of water. Soak in dye bath for 60 seconds.

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

(Production 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 the polarizing element b were measured according to the procedures described below. The results are shown in Table 1 and Table 2.

(Production of polarizer c)

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

(Production of polarizer d)

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

(Production of polarizer e)

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

[Measurement of thickness]

The thickness of each layer of the polarizer, the protective film, and the phase difference body was measured with a contact film thickness meter [trade name "DIGIMICRO (registered trademark) MH-15M" manufactured by Nikon Co., Ltd.].

[Boron content of polarizer]

Dissolve 0.2 g of polarizer in 200 g of 1.9 mass% mannitol aqueous solution. Titrate the obtained aqueous solution with 1 mol/L NaOH aqueous solution, and compare the amount of NaOH solution required for neutralization with the calibration curve Lines are compared to calculate the amount (mass) of boron. Calculate the boron content of the polarizer as the calculated amount of boron relative to the mass of the polarizer.

[Measurement of shrinkage force of polarizer]

A rectangle with a short side of 2 mm and a long side of 50 mm was cut out from the polarizing member using a super cutter (manufactured by Ogino Seiki Manufacturing Co., Ltd.) so that the absorption axis of the polarizing member coincides with the long side and was used as a test piece. The shrinkage force of the test piece was measured using a thermomechanical analysis device (manufactured by SII Nanotechnology Co., Ltd., model TMA/6100). This measurement was performed in the constant size mode, with the distance between the fixtures set to 10 mm, the static load set to 0 mN, and a SUS probe used as the jig, and carried out according to the following procedure. First, the test piece is placed in a room with a temperature of 20°C for a sufficient time. Thereafter, the temperature in the room where the test piece was placed was set to increase from 20°C to 80°C over 10 minutes. After the temperature rise, the indoor temperature was set to maintain at 80°C, and after being left for another 4 hours, the shrinkage force in the longitudinal direction (absorption axis direction) of the test piece was measured in an environment with a temperature of 80°C.

<Production of protective film>

(Easy to prepare the composition)

唑啉的聚合物，日本觸媒股份有限公司製，商品名稱：EPOCROS WS-700、固形份：25%)4.2g、1質量%之氨水2.0g、膠態氧化矽(扶桑化學工業股份有限公司製，Quartron PL-3，固形份：20質量%)0.42g、及純水76.6g混合，以獲得易接著組成物。 Mix 16.8 g of polyester urethane (manufactured by Daiichi Industrial Pharmaceutical Co., Ltd., trade name: SUPERFLEX 210, solid content: 33%), a cross-linking agent (containing

Polymer of oxazoline, manufactured by Nippon Shokubai Co., Ltd., trade name: EPOCROS WS-700, solid content: 25%) 4.2g, 1 mass% ammonia 2.0g, colloidal silicon oxide (Fuso Chemical Industry Co., Ltd. Made from Quartron PL-3, solid content: 20 mass%) 0.42g and 76.6g pure water were mixed to obtain an easy-to-adhere composition.

(Production of protective film A)

=20.0mm、L/D=25)及衣架型T模(寬度150mm)在溫度280℃進行熔融擠出屬於丙烯酸系樹脂之聚甲基丙烯酸甲酯樹脂[玻璃轉移溫度：135℃、熔融黏度：700Pa‧s(溫度270℃、剪斷速度100(1/sec))]的顆粒。藉由溫度保持在110℃之冷卻輥將擠壓出的樹脂冷卻，成形為厚度80μm之未延伸的丙烯酸系樹脂膜。將如此方式獲得的未延伸之丙烯酸系樹脂膜使用桌上型延伸機以延伸倍率2.0倍沿著長度方向延伸，從而獲得延伸膜。 Use a single-screw extruder (

=20.0mm, L/D=25) and a hanger-type T mold (width 150mm) at a temperature of 280°C to melt-extrude polymethyl methacrylate resin, which is an acrylic resin [glass transition temperature: 135°C, melt viscosity: 700Pa‧s (temperature 270℃, shearing speed 100(1/sec))] particles. The extruded resin was cooled by a cooling roll maintained at a temperature of 110°C, and formed into an unstretched acrylic resin film with a thickness of 80 μm. The unstretched acrylic resin film obtained in this manner was stretched in the longitudinal direction at a stretching magnification of 2.0 times using a desktop stretching machine to obtain a stretched film.

After applying the easy-adhesion composition prepared above on one surface of the stretched film using a bar coater, it was 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. The stretched film with the coating film was stretched in the width direction using a desktop stretching machine (stretching ratio: 2.35 times) to obtain a protective film A having an easy-adhesion layer with a thickness of 600 nm on the surface of a base layer with a thickness of 20 μm. The puncture elastic modulus E of the protective film A was measured in the following procedure. The results are shown in Table 1 and Table 2.

(Production of protective film B)

The protective film B having an easy-adhesive layer with a thickness of 300 nm on the surface of a base material layer with a thickness of 20 μm was obtained in the same manner as the protective film A except that the thickness of the coating film formed using the easy-adhesion composition was changed. . The puncture elastic modulus E of the protective film B was measured in the following procedure. The results are shown in Table 1 and Table 2.

(Production of protective film C)

Except for changing the thickness of the coating film formed by using the easy-adhesion composition, the same method as protective film A was used to obtain a base material layer with a thickness of 20 μm on the surface. 280nm protective film C for easy bonding layer. The puncture elastic modulus E of the protective film C is measured by the procedure described below. The results are shown in Table 1 and Table 2.

(Production of protective film D)

The protective film D having an easy-adhesive layer with a thickness of 180 nm on the surface of a base material layer with a thickness of 20 μm was obtained in the same manner as the protective film A except that the thickness of the coating film formed by using the easy-adhesion composition was changed. . The puncture elastic modulus E of the protective film D is measured by the procedure described below. The results are shown in Table 1 and Table 2.

(Production of protective film E)

A protective film E having an easily adhesive layer with a thickness of 80 nm on the surface of a base material layer with a thickness of 20 μm was obtained in the same manner as the protective film A except that the thickness of the coating film formed by using the easy-adhesion composition was changed. . The puncture elastic modulus E of the protective film E is measured by the procedure described below. The results are shown in Table 1 and Table 2.

(Production of protective film F)

The protective film F having an easy-adhesion layer with a thickness of 65 nm on the surface of a base material layer with a thickness of 20 μm was obtained in the same manner as the protective film A except that the thickness of the coating film formed by using the easy-adhesion composition was changed. . The puncture elastic modulus E of the protective film F is measured by the procedure described below. The results are shown in Table 1 and Table 2.

(Production of protective film G)

The easy-adhesion composition prepared above was applied to one surface of the stretched film obtained in the same manner as in the production 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 seconds. A stretched film with a coated film is obtained. The stretched film with the coating film was stretched along the width direction using a desktop stretching machine (extension ratio: 2.0 times) to obtain a base material layer with a thickness of 40 μm. The protective film G has an easy-adhesion layer with a thickness of 180 nm on the surface. The puncture elastic modulus E of the protective film G is measured by the procedure described below. The results are shown in Table 1 and Table 2.

(Production of protective film H)

Except for adjusting the hanger-type T-die and changing the thickness of the resin to be melted and extruded, the same procedure as for the production of the protective film A was performed to obtain an unstretched acrylic resin film with a thickness of 20 μm. The easy-adhesion composition prepared above was applied to one surface of the obtained unstretched acrylic resin film using a bar coater, and then put into a hot air dryer and dried at a temperature of 100° C. for 90 seconds. Thereby, a protective film H having an easy-adhesion layer with a thickness of 500 nm on the surface of a base material layer with a thickness of 20 μm was obtained. The puncture elastic modulus E of the protective film H is measured by the procedure described below. The results are shown in Table 1 and Table 2.

(Production of protective film I)

Except for adjusting the hanger-type T-die and changing the thickness of the resin to be melt-extruded, the same procedure as for the production of the protective film A was performed to obtain an unstretched acrylic resin film with a thickness of 40 μm. The easy-adhesion composition prepared above was applied to one surface of the obtained unstretched acrylic resin film using a bar coater, and then put into a hot air dryer and dried at a temperature of 100° C. for 90 seconds. Thereby, a protective film I having an easy-adhesion layer with a thickness of 500 nm on the surface of a base material layer with a thickness of 40 μm was obtained. The puncture elastic modulus E of the protective film I was measured in the following procedure. The results are shown in Table 1 and Table 2.

(Production of protective film J)

Pellets of the thermoplastic resin [glass transition point: 137°C] containing norbornene polymer were dried at a temperature of 100°C for 5 hours. The dried particles are supplied to the extruder, melted in the extruder, passed through the polymer tube and polymer filter, and extruded from the T die onto the casting drum to form a film. by casting The extruded resin was cooled by a drum to obtain a long, unstretched cyclic polyolefin (COP)-based resin film with a thickness of 50 μm and a width of 1500 mm. The thus-obtained COP-based resin film was stretched in the longitudinal direction at a stretching magnification of 1.5 times and a stretching temperature of 145°C to obtain a strip-shaped stretched COP film with a thickness of 40 μm and a width of 1000 mm.

A manufacturing device is prepared, including a tenter extending device including an inner nip strip and an outer nip strip, and an oven covering the tenter extending device. The stretched COP film obtained above is continuously supplied to a tenter stretching device and stretched diagonally. The stretching conditions are a stretching magnification of 2.1 times, a stretching temperature of 142°C, and a tension ratio Tin/Tout×100 of the inner and outer sandwich strips 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 by the procedure described below. The results are shown in Table 1 and Table 2.

(Production of protective film K)

=20.0mm、L/D=25)及衣架型T模(寬度150mm)在溫度250℃熔融擠出。藉由溫度保持在90℃之冷卻輥冷卻被擠出的樹脂，從而獲得僅由厚度25μm之基材層所構成的保護膜K。以後述程序測定保護膜K之穿刺彈性模數E。將結果示於表1及表2。 Polymethylmethacrylate resin, which is an acrylic block copolymer with a core-shell structure [glass transition temperature: 105°C, melt viscosity: 700Pa‧s (temperature 240°C, shear speed 100 (1/sec))] pellets, using a single-screw extruder (

=20.0mm, L/D=25) and hanger-type T-die (width 150mm) are melted and extruded at a temperature of 250°C. The extruded resin is cooled by a cooling roll maintained at a temperature of 90° C., thereby obtaining a protective film K consisting only of a base material layer with a thickness of 25 μm. The puncture elastic modulus E of the protective film K is measured in the following procedure. The results are shown in Table 1 and Table 2.

[Measurement of puncture elastic modulus E of protective film]

0.5R之針以0.33cm/秒之速度，對於該保護膜的面以約略垂直之方式進行穿刺。然後，在產生破裂之時間點所測定之以該保護膜在穿刺方向撓曲所造成之位移量作為應變量S[mm]，以施加在該保護膜之應力作為F[g]時，應力F除以應變量S而求出穿刺彈性模數E[g/mm]。亦即，藉由下式(1)求出穿刺彈性模數E。將結果示於表1及表2。 A measurement sample is produced. The measurement sample is made by cutting out a 30 mm × 30 mm square at the center to form an adhesive cardboard with a gap, and laminating the protective film of the measurement object. When the protective film has an easily adhesive layer, prepare a measurement sample so that the easily adhesive layer side of the protective film becomes the bonding surface with the adhesive cardboard. In an environment with a temperature of 25°C and a relative humidity of 55%, the center of the protective film of the test sample located in the gap is 1 mm in diameter at the front end.

The 0.5R needle punctures the surface of the protective film in an approximately vertical manner at a speed of 0.33cm/second. Then, when the displacement amount caused by the deflection of the protective film in the puncture direction is taken as the strain amount S [mm] and the stress exerted on the protective film is taken as F [g], the stress F is measured at the time point when the rupture occurs. Divide the strain amount S to obtain the puncture elastic modulus E [g/mm]. That is, the puncture elastic modulus E is calculated by the following equation (1). The results are shown in Table 1 and Table 2.

Puncture elastic modulus E[g/mm]=F[g]/S[mm] (1)

<Preparation of retardation body (A) with base film>

(Preparation of the first laminated body (A))

5 parts by mass of a photo-alignment material having the structure shown below (weight average molecular weight: 30,000) and 95 parts by mass of cyclopentanone were mixed, and the obtained mixture was stirred at 80° C. for 1 hour to obtain an alignment layer forming material. Coating liquid (1) for forming a horizontal alignment layer of the composition.

啉基苯基)丁-1-酮(「Irgacure 369(Irg369)」，BASF日本股份有限公司製)6質量份。更且，以固形份濃度成為13%之方式，添加N-甲基-2-吡咯啶酮(NMP)，藉由在80℃攪拌1小時，獲得作為液晶硬化層形成用之組成物的液晶層形成用塗佈液(1)。 A leveling agent (F-556; DIC Co., Ltd.) was added to 100 parts by mass of a mixture of a polymerizable liquid crystal compound a and a polymerizable liquid crystal compound b having the structure shown below in a mass ratio of 90:10. (Prepared) 1.0 parts by mass, and 2-dimethylamino-2-benzyl-1-(4-) which is a polymerization initiator

6 parts by mass of lynylphenyl)butan-1-one ("Irgacure 369 (Irg369)", manufactured by BASF Japan Co., Ltd.). Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration became 13%, and the liquid crystal layer was obtained as a composition for forming a liquid crystal hardened layer by stirring at 80° C. for 1 hour. Forming coating liquid (1).

Polymerizable liquid crystal compound a:

Polymeric liquid crystal compound b:

The polymerizable liquid crystal compound a is produced by the method described in Japanese Patent Application Laid-Open No. 2010-31223. The polymerizable liquid crystal compound b is produced according to the method described in Japanese Patent Application Laid-Open No. 2009-173893.

A corona treatment device (AGF-B10, manufactured by Kasuga Electric Co., Ltd.) was used on the cyclic olefin polymer (COP) film (ZF-14 manufactured by Japan ZEON Co., Ltd., thickness 23 μm) as the base film to output 0.3 kW and a processing speed of 3m/min for one corona treatment. The coating liquid (1) for forming a horizontal alignment layer is applied to the surface of the corona-treated base film using a rod coater. The coating film was dried at a temperature of 80° C. for 1 minute, and polarized UV exposure was performed with a cumulative light amount of 100 mJ/cm ² using a polarized UV irradiation device (SPOT CURE SP-7; manufactured by USHIO Electric Co., Ltd.). Thereby, a base material film with a horizontal alignment layer and a horizontal alignment layer formed on the base film is obtained. When measured with a laser microscope (LEXT, manufactured by Olympus Co., Ltd.), the thickness of the horizontal alignment layer was 100 nm.

Then, in an environment with a temperature of 25° C. and a relative humidity of 30%, the liquid crystal layer forming coating liquid (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. Thereafter, the coating liquid (1) for forming a liquid crystal hardened layer was coated on the horizontal alignment layer of the base film with the horizontal alignment layer maintained at 25° C. using a rod coater, and the coating layer was After drying at 120°C for 1 minute, a high-pressure mercury lamp (UNICURE VB-15201BY-A, manufactured by USHIO Electric Co., Ltd.) was used to irradiate ultraviolet rays (in a nitrogen environment, at a wavelength of 365 nm, the accumulated light amount at a wavelength of 365 nm: 1000 mJ/cm ² ). When measured with a laser microscope (LEXT, manufactured by Olympus Co., Ltd.), the thickness of the obtained first liquid crystal hardened layer was 2 μm. Thereby, the 1st laminated body (A) in which the 1st retardation layer was formed on the base film was obtained. The first laminated body (A) has an alignment layer and a first liquid crystal cured layer in which a nematic liquid crystal compound is cured in order from the base film side, and the first retardation layer is a λ/4 retardation layer.

(Preparation of the second laminated body (A))

10.0 parts by mass of polyethylene glycol diacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-600) and 10.0 parts by mass of trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-TMPT) parts, 10.0 parts by mass of 1,6-hexanediol diacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-HD-N), and Irgacure907 (manufactured by BASF, Irg-907) as a photopolymerization initiator 1.50 parts by mass was dissolved in 70.0 parts by mass of the solvent methyl ethyl ketone to prepare an alignment layer forming coating liquid (2) as a composition for forming the alignment layer.

As a base film, a long cyclic olefin-based resin (COP) film (manufactured by Japan ZEON Co., Ltd.) with a thickness of 20 μm was prepared, and the alignment layer forming coating liquid (2) was applied using a bar coater. One side of the base film. After heat treatment for 60 seconds at a temperature of 80°C, the coated coating layer is irradiated with ultraviolet light (UVB) 220 mJ/cm ² to polymerize and harden the monomer components in the alignment layer forming coating liquid (2), and An alignment layer with a thickness of 2.3 μm was formed on the base film.

20.0 parts by mass of a photopolymerizable nematic liquid crystal compound (manufactured by Merck, RMM28B) as a composition for forming a liquid crystal hardened layer, and 1.0 parts by mass of Irgacure907 (manufactured by BASF, Irg-907) as a photopolymerization initiator , was dissolved in 80.0 parts by mass of the solvent propylene glycol monomethyl ether acetate to prepare a coating liquid (2) for forming a liquid crystal layer.

The coating liquid (2) for forming a liquid crystal layer was applied on the alignment layer formed on the base film, and the coating layer was heat-treated at a temperature of 80° C. for 60 seconds. Thereafter, ultraviolet (UVB) 220 mJ/cm ² was irradiated to polymerize and harden the photopolymerizable nematic liquid crystal compound, and a second liquid crystal hardened layer with a thickness of 0.7 μm was formed on the alignment layer. Thereby, the second laminated body (A) in which the second retardation layer composed of the alignment layer and the second liquid crystal cured layer is formed on the base film is obtained. The second phase difference layer is the positive C layer. The thickness of the second retardation layer is 3 μm.

(Preparation of retardation element (A) with base film)

The first laminated body (A) and the second laminated body (A) are laminated so that the first retardation layer side and the second retardation layer side face each other via the ultraviolet curable adhesive. Next, ultraviolet rays are irradiated to harden the ultraviolet curable adhesive to form an adhesive layer with a thickness of 1 μm, thereby producing a retardation body (A) with a base film.

<Preparation of water-based adhesive>

Dissolve 3 parts by mass of carboxyl-modified polyvinyl alcohol (Kuraray Co., Ltd., trade name "KL-318") with respect to 100 parts by mass of water, and add a polyamide epoxy system that is a water-soluble epoxy resin to the aqueous solution. Additive (Taoka Chemical Industry Co., Ltd., trade name "Sumirez Resin (registered trademark) 650 (30), an aqueous solution with a solid content concentration of 30 mass%) 1.5 parts by mass to prepare a water-based adhesive.

[Examples 1 to 7, Comparative Examples 1 to 8]

(Production of polarizing plates)

Use the polarizer and protective film shown in Table 1 and Table 2, use the water-based adhesive prepared above to bond the protective film to one side of the polarizer, and harden the water-based adhesive to form an adhesive layer (laminated layer) , to make polarizing plates. When the protective film has an easily adhesive layer, the polarizer and the protective film are laminated so that the easily adhesive layer side becomes the polarizer side. The elongation at break and the adhesion force of the produced polarizing plate were measured by the procedure described below. The results are shown in Table 1 and Table 2.

(Preparation of acrylic adhesive layer a)

For 100 parts by mass of butyl acrylate/acrylic acid copolymer (a copolymer polymerized using butyl acrylate and acrylic acid with a mass ratio of 95:5, a weight average molecular weight of 2 million, and a molecular weight distribution (Mw/Mn) of 3.0), prepare 20 parts of polyfunctional acrylate monomer ((acryloyloxyethyl) isocyanurate (molecular weight: 423, trifunctional type (manufactured by Toagosei Co., Ltd., Aronix M-315)), as photopolymerized 1.5 parts by mass of the starting agent (a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1:1, manufactured by Chiba Specialty Chemicals, Irgacure 500), and Coronate L (Tosoh Co., Ltd.) as a cross-linking agent Co., Ltd.) and 0.2 parts by mass of KBM-403 (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) as a silane coupling agent to prepare a coating solution of the adhesive composition. The thickness after drying and ultraviolet irradiation as described below After applying the above-mentioned coating solution to the release-treated surface of the release film (thickness 38 μm polyterephthalate release film, manufactured by LINTEC Co., Ltd., SP-PET3811) using a blade coater, the temperature Drying is performed at 90°C for 1 minute to form a layer of adhesive composition. The layer of the adhesive composition is irradiated with ultraviolet rays (illuminance 600mW/cm ² , light intensity 15mJ/cm ² , using an electrodeless lamp H bulb manufactured by Fusion Corporation). To obtain the acrylic adhesive layer a. Use a UV illuminance and photometer (UVPF-36 manufactured by Eye Graphics Co., Ltd.) to determine the illuminance and light amount of ultraviolet irradiation.

(Production of optical laminates)

An optical laminated body including the polarizing plate produced above and the retardation body in which two layers of base film were peeled off from the retardation body (A) with a base film was produced. The optical lamination system is obtained by laminating a retardation body on the side of the polarizing plate opposite to the protective film side via the acrylic adhesive layer a obtained above. The retardation body and the polarizing plate are laminated so that the first retardation layer side is the polarizer side. The produced optical laminate was subjected to an impact resistance test and a bending test in the procedures described below. The results are shown in Table 1 and Table 2.

[Measurement of breaking elongation of polarizing plates]

The elongation at break was measured for polarizing plates with polarizers and protective films. Cut out a rectangular polarizing plate with a length of 100mm in the absorption axis direction and a length of 25mm in the transmission axis direction. The mark distance is set to 50mm, and a tensile testing machine (AUTOGRAPH AG-1S manufactured by Shimadzu Corporation) is used at a temperature of 25°C and a relative humidity of 55% at a tensile speed of 10mm/min. Conduct a 180° tensile test on the absorption axis direction of the polarizing plate to measure the elongation at break in the absorption axis direction.

Cut out a rectangular polarizing plate with a length of 100mm in the transmission axis direction and a length of 25mm in the absorption axis direction. The mark distance is set to 50mm, and a tensile testing machine (AUTOGRAPH AG-1S manufactured by Shimadzu Corporation) is used at a temperature of 25°C and a relative humidity of 55% at a tensile speed of 10mm/min. A 180° tensile test is performed on the polarizing plate produced in the direction of the penetration axis to measure the elongation at break in the direction of the penetration axis.

[Measurement of the tight adhesion of polarizing plates]

(Preparation of acrylic adhesive layer b)

Into a reaction vessel equipped with a mixer, a thermometer, a reflux cooler, a dripping device, and a nitrogen inlet pipe, 97.0 parts by mass of n-butyl acrylate, 1.0 parts by mass of acrylic acid, 0.5 parts by mass of 2-hydroxyethyl acrylate, and 200 parts by mass of ethyl acetate were fed. parts by mass, and 0.08 parts by mass of 2,2'-azobisisobutyronitrile, and the air in the above reaction vessel was replaced with nitrogen. The reaction solution was heated to 60° C. while stirring in a nitrogen environment. After reacting for 6 hours, the reaction solution was cooled to room temperature to obtain a (meth)acrylate polymer with a weight average molecular weight of 1.8 million. 100 parts by mass of this (meth)acrylate polymer (solid content conversion value; the same below), trimethylolpropane-modified toluene diisocyanate (Coronate L manufactured by Tosoh Co., Ltd.) as an isocyanate-based cross-linking agent ) 0.30 parts by mass and 0.30 parts by mass of 3-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Industry Co., Ltd.) as a silane coupling agent were mixed and thoroughly stirred, and diluted with ethyl acetate. A coating solution of the adhesive composition was thus obtained. Use an applicator to apply the above-mentioned coating solution to the release-treated surface of the release film (manufactured by LINTEC Co., Ltd., SP-PLR382190) so that the thickness after drying is 25 μm, and then dry at 100°C for 1 minute. This obtains the acrylic adhesive layer b.

(Measurement of tight adhesion)

Cut out a rectangular polarizing plate with a length of 100mm in the absorption axis direction and a length of 25mm in the transmission axis direction. The polarizer side of the cut out polarizing plate was pressed against alkali-free glass via the acrylic adhesive layer b obtained above, and then sterilized by high pressure at a temperature of 50°C and a load of 5kg for 20 minutes, and then sterilized at a temperature of 23°C and a load of 5kg. Let stand for 10 hours in an environment with relative humidity of 60%RH. Thereafter, the end of the protective film pressed against the alkali-free glass polarizing plate was peeled off, and a tensile testing machine [Shimadzu Co., Ltd. "AUTOGRAPH AG-I" manufactured by Seiko Co., Ltd.], a 180° peeling test was conducted at a tension speed of 300m/min at a temperature of 25°C.

[Impact resistance test of optical laminates (pen-down test)]

Use a super cutting machine to cut the rectangular optical laminate with a length of 150 mm in the absorption axis direction and a length of 70 mm in the transmission axis direction. The retardation body side of the cut out optical laminate is 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, hold the optical laminate attached to the acrylic plate with the tip of the pen at a height of 5cm from the outermost surface of the protective film of the optical laminate and with the tip of the pen facing downwards. Drop the evaluation pen from this position. As a pen for evaluation, I used a pen with a mass of 11g and a pen tip diameter of 0.7mm. After dropping the evaluation pen, the optical laminate is visually observed and evaluated based on the following standards. The evaluation results are shown in Table 1 and Table 2.

A: Neither the polarizer nor the protective film has cracks or scratches.

B: There are no cracks or scratches on the polarizer, but there are cracks or scratches on the protective film.

C: Cracks or scratches occur on the polarizer.

[Bending test of optical laminate]

Using a bend evaluation equipment (STS-VRT-500 manufactured by Science Town Co., Ltd.), a bend test to confirm the bending durability of the optical laminate was performed in an environment with a temperature of 25°C. Determine the bending axis, align it until the bending radius along the bending axis is 1.5mm and the areas on both sides of the bending axis are parallel, bend the protective film side inward, and then repeat the releasing and bending action 135,000 times. Bending evaluation (1) visually determines peeling along the bending axis and evaluates based on the following standards. Bending evaluation (2) measures the length of cracks generated along the bending axis and evaluates based on the following standards.

(Bend Assessment(1))

AA: No peeling occurred in the bending axis portion of the optical laminate.

A: Point-like peeling occurs in the curved axis portion of the optical laminate.

B: Partial linear peeling occurred in the curved axis portion of the optical laminate.

C: The entire bending axis portion of the optical laminate was peeled off.

(Bend evaluation(2))

A: The cracks generated in the bent axis portion of the optical laminate are 1mm or less.

B: Cracks occurring in the bent axis portion of the optical laminate exceed 1 mm and are less than 5 mm.

C: Cracks generated in the bent axis portion of the optical laminate exceed 5 mm.

[Table 1]

[Table 2]

<Preparation of retardation body (B) with base film>

(Preparation of the first laminated body (B))

A first laminated body (B) in which a first retardation layer is formed on a base film is prepared. The first laminated body (B) has an alignment layer on a base film (cycloolefin polymer film) and a first liquid crystal layer formed by hardening a liquid crystal compound, and the first retardation layer is a λ/2 retardation layer. The first laminated body (B) is produced by the manufacturing process of the layer B (B-1) described in Example 2 of Japanese Patent Application Laid-Open No. 2015-163935.

(Preparation of the second laminated body (B))

A second laminated body (B) in which a second retardation layer is formed on a base film is prepared. The second laminated body (B) has an alignment layer on a base film (cycloolefin polymer film) and a second liquid crystal layer formed by hardening a liquid crystal compound, and the second retardation layer is a λ/4 retardation layer. The second laminated body (B) is produced by the manufacturing process of the layer A (A-1) described in Example 2 of Japanese Patent Application Laid-Open No. 2015-163935.

(Preparation of ultraviolet curable adhesive)

Mix the following ingredients to obtain a UV curable adhesive.

‧3',4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Co., Ltd.): 70 parts by mass

‧Neopentyl glycol diglycidyl ether (trade name: EX-211, manufactured by Nagase ChemteX Co., Ltd.): 20 parts by mass

‧2-Ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Co., Ltd.): 10 parts by mass

‧Cationic polymerization initiator (trade name: CPI-100_50% solution, manufactured by San-Apro Co., Ltd.): 4.5 parts by mass (substantial solid content 2.25 parts by mass)

‧1,4-diethoxynaphthalene: 2 parts by mass

(Preparation of retardation element (B) with base film)

The first laminated body (B) and the second laminated body (B) are laminated so that the first retardation layer side and the second retardation layer side face each other via the ultraviolet curable adhesive prepared above. Next, ultraviolet rays are irradiated to harden the ultraviolet curable adhesive to form an adhesive layer with a thickness of 1 μm, thereby producing a retardation body (B) with a base film.

[Examples 8 to 14]

An optical laminated body was produced in the same manner as in Examples 1 to 7 except that the retardation body with a base film (B) was used instead of the retardation body (A) with a base film. When the impact resistance test and the bending test of the optical laminate were conducted according to the above procedures, the results were the same as those in Examples 1 to 7.

1:Polarizing plate

10:Polarizer

20:Protective film

21:Substrate layer

22: Easy to adhere layer

41: The first laminating layer (laminated layer)

Claims (9)

A polarizing plate, which is provided with a polarizing element containing polyvinyl alcohol resin and boron, and a protective film; wherein, The boron content of the aforementioned polarizer is 2.8 mass% or more and 4.7 mass% or less. The protective film has a base material layer and an easy-adhesion layer laminated on the polarizer side of the base material layer, The thickness of the aforementioned base material layer is 30 μm or less, The thickness of the aforementioned easy-adhesive layer is not less than 70nm and not more than 800nm, The elongation at break of the aforementioned polarizing plate in the absorption axis direction and the transmission axis direction at a temperature of 25°C and a relative humidity of 55% is both 4.0% and below 14.0%. The polarizing plate according to claim 1, wherein the thickness of the polarizing element is 12 μm or less. The polarizing plate according to claim 1 or 2, wherein the puncture elastic modulus of the protective film at a temperature of 25° C. and a relative humidity of 55% is 210 g/mm or more and 550 g/mm or less. The polarizing plate according to any one of claims 1 to 3, wherein the base material 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 via a lamination layer. An optical laminate including the polarizing plate, the retardation body, and the adhesive layer described in any one of claims 1 to 6 in this order. The optical laminate according to claim 7, wherein the polarizing plate is provided with the protective film on one side of the polarizer, The optical laminated body includes a retardation body on a side of the polarizer opposite to the protective film side, The retardation body includes a liquid crystal hardened layer. A display device including the optical laminated body according to claim 7 or 8.

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