JP2021121862A - Polarizing plate and display device - Google Patents

Abstract

To provide a circularly polarizing plate comprising a retardation film using a polymerizable liquid crystal compound and is characterized in that an in-plane retardation difference thereof before and after being exposed to a high-temperature high-humidity environment does not easily increase.SOLUTION: A circularly polarizing plate is provided, comprising a polarizing plate and a retardation film. The polarizing plate comprises a polarizer and a protective film pasted on at least one surface of the polarizer, where the polarizer is a polyvinyl alcohol resin film with iodine absorbed and aligned therein, and contains 1.00 wt.% or more of boron. The protective film has a moisture permeability of 50 g/m2/24hr or greater. The retardation film comprises a retardation layer made of a cured polymerizable liquid crystal compound.SELECTED DRAWING: None

Description

The present invention relates to a polarizing plate and a display device.

In recent years, image display devices typified by organic electroluminescence (hereinafter, also referred to as organic EL) display devices have rapidly become widespread. The organic EL display device is equipped with a circularly polarizing plate including a polarizer and a retardation film (λ / 4 plate). By arranging the circularly polarizing plate, it is possible to prevent reflection of external light and improve the visibility of the screen.

With the rise of organic EL display devices, there is a growing demand for thinner image display devices, and there is also a demand for thinner circular polarizing plates. It has been studied to change from a conventional retardation film formed by molding a resin film to a retardation film formed of a liquid crystal compound capable of being thinned (see, for example, Patent Document 1). A retardation film using a polymerizable liquid crystal compound is produced by coating a polymerizable liquid crystal compound on a substrate, aligning it, and if necessary, irradiating it with light to fix the oriented state.

JP-A-2017-54093

It has been found that when a circularly polarizing plate having a retardation film using a polymerizable liquid crystal compound is placed in a high temperature and high humidity environment, there is a problem that the in-plane retardation value of the retardation film increases. An increase in the in-plane retardation value may change the reflected hue and deteriorate the visibility of the image display device. An object of the present invention is a circularly polarizing plate provided with a retardation film using a polymerizable liquid crystal compound, wherein the in-plane retardation value of the retardation film does not easily increase before and after being placed in a high temperature and high humidity environment. Is to provide.

[1] A circular polarizing plate having a polarizing plate and a retardation film.
The polarizing plate includes a polarizing element and a protective film attached to at least one surface of the polarizing element.
The polarizer is a film in which iodine is adsorbed and oriented on a polyvinyl alcohol-based resin film.
The boron content of the polarizer is 1.00% by weight or more.
Moisture permeability of the protective film is a ^50g / m 2 · 24hr or more,
The retardation film is a circularly polarizing plate including a retardation layer composed of a layer obtained by curing a polymerizable liquid crystal compound.
[2] The circularly polarizing plate according to [1], wherein the thickness of the polarizer is 20 μm or less.
[3] The circular polarizing plate according to [1] or [2], wherein the visual sensitivity correction single-unit transmittance of the polarizer is 40% or more.
[4] The method according to any one of [1] to [3], wherein the contractile stress in the absorption axis direction per width of 2 mm is 60 N / mm ^{2 or more when the polarizer is held at 80 ° C. for 4 hours.} Circularly polarized light.
[5] The single hues of the polarizers of [1] to [4] have an a * value of −0.90 or more and −0.60 or less and a b * value of 2.70 or more and 3.70 or less. The circularly polarizing plate according to any one.
[6] The retardation film includes an alignment film and contains an alignment film.
The circularly polarizing plate according to any one of [1] to [5], wherein the alignment film is located between the polarizer and the retardation layer.
[7] The circularly polarizing plate according to any one of [1] to [6], wherein the polarizing plate and the retardation film are bonded together with an active energy ray-curable adhesive.
[8] The polarizing plate is provided with protective films on both surfaces of the polarizer.
Moisture permeability of one of the protective film is a 500g ^/ m 2 · 24hr or more,
The moisture permeability of the other protective film, a circular polarizing plate according to any one of equal to or less than ^{100g / m 2 · 24hr [1} ] ~ [7].
[9] The circularly polarizing plate according to any one of [1] to [8], which further has a front plate, a light-shielding pattern, and a touch sensor.
[10] A display device including the circularly polarizing plate according to any one of [1] to [9] and a display element.

According to the present invention, it is a circularly polarizing plate provided with a retardation film using a polymerizable liquid crystal compound, and the in-plane retardation value of the retardation film does not easily increase before and after being placed in a high temperature and high humidity environment. Can be provided.

This is an example of a schematic cross-sectional view showing the layer structure of a circularly polarizing plate. This is an example of a schematic cross-sectional view showing a layer structure of an organic EL display device.

<Circular polarizing plate>
The circularly polarizing plate of the present invention has a polarizing plate and a retardation film. The polarizing plate and the retardation film can be laminated, for example, via an adhesive layer. Examples of the adhesive layer include an adhesive layer and an adhesive layer described later. In the present invention, the polarizing plate refers to a laminate containing a polarizing element and a protective film bonded to at least one surface of the polarizing element.

Hereinafter, an example of the layer structure of the circularly polarizing plate of the present invention will be described with reference to FIG. In FIG. 1, the adhesive layer for adhering the polarizer 10 and the protective films 11 and 12, respectively, is not shown. In the circular polarizing plate 100 shown in FIG. 1A, the first protective film 11 is laminated on one surface of the polarizing element 10, and the second protective film 12 is laminated on the other surface of the polarizing element 10. The polarizing plate 1 and the retardation film 2 including the layer 20 on which the polymerizable liquid crystal compound is cured have a layer structure in which they are laminated via the pressure-sensitive adhesive layer 13. Further, the circularly polarizing plate 100 has an adhesive layer 14 on the surface of the retardation film 2 opposite to the polarizing plate 1. The pressure-sensitive adhesive layer 14 can be a pressure-sensitive adhesive layer for bonding to an organic EL display element, a touch sensor, or the like.

In the circularly polarizing plate 101 shown in FIG. 1B, the first protective film 11 is laminated on one surface of the polarizing element 10, and the second protective film 12 is laminated on the other surface of the polarizing element 10. The polarizing plate 1 and the retardation film 2 have a layer structure in which the polarizing plate 1 and the retardation film 2 are laminated via the pressure-sensitive adhesive layer 13. In the circularly polarizing plate 101, the retardation film 2 has a layer structure in which a layer 20 in which a polymerizable liquid crystal compound is cured and a layer 21 in which a polymerizable liquid crystal compound is cured are laminated via an adhesive layer 15. Further, the circularly polarizing plate 101 has an adhesive layer 14 on the surface of the retardation film 2 opposite to the polarizing plate 1. The pressure-sensitive adhesive layer 14 can be a pressure-sensitive adhesive layer for bonding to an organic EL display element, a touch sensor, or the like.

In the circularly polarizing plate 103 shown in FIG. 1C, a polarizing plate 1 in which a first protective film 11 is laminated on one surface of a polarizer 10 and a retardation film 2 are interposed via an adhesive layer 13. It has a laminated layer structure. In the circular polarizing plate 103, the polarizing plate 1 is a polarizing plate having a protective film on only one surface of the polarizer 10. In the circularly polarizing plate 103, the retardation film 2 has a layer structure in which a layer 20 in which a polymerizable liquid crystal compound is cured and a layer 21 in which a polymerizable liquid crystal compound is cured are laminated via an adhesive layer 15. Further, the circularly polarizing plate 103 has the pressure-sensitive adhesive layer 14 on the surface of the retardation film 2 opposite to the polarizing plate 1. The pressure-sensitive adhesive layer 14 can be a pressure-sensitive adhesive layer for bonding to an organic EL display element, a touch sensor, or the like.

As shown in FIG. 1, the retardation film may have one retardation layer or two retardation layers. Further, it is preferable that the retardation film has an alignment film for orienting the polymerizable liquid crystal compound at the production stage thereof, in addition to the retardation layer. As shown in FIG. 1, the polarizing plate may have a protective film laminated on only one surface of the polarizer, or may be laminated on both surfaces.

The circularly polarizing plate can have a layer other than the layer shown in FIG. Examples of the layer that the circularly polarizing plate may further include include a front plate, a light-shielding pattern, and a touch sensor. The front plate can be arranged on the side of the polarizing plate opposite to the side on which the retardation film is laminated.

The light-shielding pattern can be formed on the surface of the front plate on the polarizing plate side. The shading pattern is formed on the frame (non-display area) of the image display device so that the wiring of the image display device is not visible to the user.

The touch sensor is arranged on the surface of the retardation film opposite to the polarizing plate side. The touch sensor may be arranged between the front plate and the polarizing plate. The touch sensor is used as an input means.
As the touch sensor, various types such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and a capacitance method have been proposed, and any method may be used. Of these, the capacitance method is preferable. The capacitive touch sensor is divided into an active region and an inactive region located outside the active region. The active area is an area corresponding to the area where the screen is displayed on the display panel (display unit), the area where the user's touch is sensed, and the inactive area is the area where the screen is not displayed on the display device (non-active area). This is the area corresponding to the display unit). The touch sensor is formed on a substrate having flexible characteristics; a sensing pattern formed in an active region of the substrate; and is formed in an inactive region of the substrate, and is connected to an external drive circuit via the sensing pattern and a pad portion. Each sensing line for can be included. A touch sensor substrate having a toughness of 2,000 MPa% or more is preferable from the viewpoint of suppressing cracks that may occur in the touch sensor. More preferably, the toughness is 2,000 MPa% to 30,000 MPa%. Here, toughness is defined as the lower area of the curve to the fracture point in the stress-strain curve obtained through the tensile test of the polymer material.

The shape of the main surface of the circularly polarizing plate can be substantially rectangular. The main surface means the surface having the largest area corresponding to the display surface. A substantially rectangular shape is a shape in which at least one of the four corners (corners) is cut off at an obtuse angle, a rounded shape, or an end face perpendicular to the main surface. A part of the main surface has a recess (notch) that is recessed in the in-plane direction, or a part of the main surface is a perforated part that is hollowed out into a shape such as a circle, an ellipse, a polygon, or a combination thereof. It means that you may have it.

The size of the circularly polarizing plate is not particularly limited. When the circularly polarizing plate is substantially rectangular, the length of the long side is preferably 6 cm or more and 35 cm or less, more preferably 10 cm or more and 30 cm or less, and the length of the short side is 5 cm or more and 30 cm or less. It is preferably 6 cm or more and 25 cm or less.

<Polarizer>
In the present invention, the polarizing plate includes a polarizing element and a protective film attached to at least one surface of the polarizing element. That is, the polarizing plate refers to a laminate composed of a polarizing element and a protective film bonded to one side or both sides of the polarizing element. The protective film included in the polarizing plate may have a surface treatment layer such as a hard coat layer, an antireflection layer, and an antistatic layer, which will be described later. The polarizer and the protective film can be laminated, for example, via an adhesive layer or an adhesive layer. The members included in the polarizing plate will be described below.

(1) Polarizer The polarizing plate included in the polarizing plate absorbs linearly polarized light having a vibrating surface parallel to its absorption axis and transmits linearly polarized light having a vibrating surface orthogonal to the absorption axis (parallel to the transmission axis). It can be an absorption type polarizer having properties. In the present invention, the polarizer used is a polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented.

In a high temperature and high humidity environment, the phenomenon that the in-plane retardation value of the retardation film rises causes moisture _{to elute iodine (particularly I 3} ⁻ ) contained in the polarizer, and the iodine is transferred to the retardation film. It has been clarified by the examination of the present inventors that this occurs. Therefore, when iodine is adsorbed and oriented on the polyvinyl alcohol-based resin film as in the present invention, it is easy to obtain the effect that the phase difference value is unlikely to increase in a high temperature and high humidity environment.

In order to prevent the elution of iodine in a high temperature and high humidity environment, it is preferable to increase the crosslink density of the polarizer. As will be described later, the polarizer is produced through a step of immersing a polyvinyl alcohol-based resin film in an aqueous boric acid solution, and boric acid crosslinks the polyvinyl alcohol-based resin chains with each other. When the crosslink density of the polarizer is high, iodine is easily retained in the polarizer even in a moist heat environment. Since the cross-linking density of the polarizer is considered to be related to the boron content in the polarizer, the boron content of the polarizer in the present invention is 1.00% by weight or more and 1.80% by weight or more. It is preferable, it is more preferably 2.00% by weight or more, and further preferably 2.50% by weight or more. The upper limit is not particularly limited, but the boron content of the polarizer may be 10.00% by weight or less, 8.00% by weight or less, or 6.00% by weight or less. You may. The boron content of the polarizer is measured by the method described in Examples below.

In other words, in order to prevent the elution of iodine in a high temperature and high humidity environment, it is preferable to increase the contraction stress of the polarizer. This is because the contractile stress of the polarizer reflects the degree of cross-linking by boric acid. When the polarizer is held at 80 ° C. for 4 hours, the shrinkage stress in the absorption axis direction per width of 2 mm ^{is preferably 60 N / mm 2} or more, more preferably 80 N / mm ² or more, and 85 N / mm. It is more preferably ^{2 or more.} The upper limit value is not particularly limited, contractile force of the polarizer may also be 120 N / mm ² or less, it may be 110N / mm ² or less. The contractile force of the polarizer is specifically measured by the method described in Examples below. The boron content and shrinkage stress can be controlled by, for example, a stretching treatment or a crosslinking treatment.

The polarizer is, for example, a step of uniaxially stretching a polyvinyl alcohol-based resin film; a step of adsorbing iodine by dyeing the polyvinyl alcohol-based resin film with iodine; a polyvinyl alcohol-based resin film on which iodine is adsorbed, such as a boric acid aqueous solution. It can be produced by a method including a step of treating the polyvinyl alcohol-based resin film with the cross-linking solution of the above; a step of treating the polyvinyl alcohol-based resin film with metal ions; and a step of washing the polyvinyl alcohol-based resin film with water.

As the polyvinyl alcohol-based resin, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable with the vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

As used herein, the term "(meth) acrylic" means at least one selected from acrylic and methacryl. The same applies to "(meth) acryloyl", "(meth) acrylate" and the like.

The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can be used. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10000, preferably 1500 to 5000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726.

A film formed of such a polyvinyl alcohol-based resin is used as a raw film for a polarizer. The method for forming a film of the polyvinyl alcohol-based resin is not particularly limited, and a known method is adopted. The thickness of the polyvinyl alcohol-based raw film is not particularly limited, but in order to reduce the thickness of the polarizer to 15 μm or less, it is preferable to use a film having a thickness of 5 to 35 μm. More preferably, it is 20 μm or less.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing with iodine, at the same time as dyeing, or after dyeing. If the uniaxial stretching is performed after staining, the uniaxial stretching may be performed before or during the cross-linking treatment. Moreover, uniaxial stretching may be performed in these a plurality of steps.

In uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched, or thermal rolls may be used to uniaxially stretch the rolls. The uniaxial stretching may be a dry stretching in which the film is stretched in the atmosphere, or a wet stretching in which the polyvinyl alcohol-based resin film is swollen with a solvent or water. The draw ratio is usually 3 to 8 times.

As a method of dyeing a polyvinyl alcohol-based resin film with iodine, for example, a method of immersing the film in an aqueous solution containing iodine is adopted. The polyvinyl alcohol-based resin film is preferably immersed in water before the dyeing treatment.

As the cross-linking treatment after dyeing with iodine, a method of immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution is usually adopted. The boric acid-containing aqueous solution preferably contains potassium iodide.

The boric acid concentration of the boric acid-containing aqueous solution is preferably 1.0 to 8.0 parts by weight, preferably 1.5 to 6.0 parts by weight, based on 100 parts by weight of water. More preferably, it is 0 to 5.5 parts by weight or less. The potassium iodide concentration of the boric acid-containing aqueous solution is preferably 0.1 to 20 parts by weight, preferably 1.0 to 15 parts by weight, based on 100 parts by weight of water. Increasing the boric acid concentration tends to increase the boron content.

The temperature of the boric acid-containing aqueous solution is preferably 40 to 80 ° C, preferably 60 to 70 ° C. When the temperature is raised, the cross-linking reaction tends to proceed. The cross-linking treatment time is preferably 1 second to 10 minutes, and preferably 10 seconds to 5 minutes.

The cross-linking treatment may be performed once or may be divided into a plurality of times. When the cross-linking treatment is performed in a plurality of times, the boric acid concentration, the potassium iodide concentration, the temperature of the boric acid-containing aqueous solution, and the cross-linking treatment time may be the same or different in each of the cross-linking treatments. May be good.

The metal ion treatment can be performed by immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a metal salt. By metal ion treatment, various metal ions can be contained in the polyvinyl alcohol-based resin film. As the metal ions, metal ions of transition metals such as cobalt, nickel, zinc, chromium, aluminum, copper, manganese, and iron are particularly preferable from the viewpoint of color tone adjustment and durability imparting. Among these metal ions, zinc ions are preferable from the viewpoint of adjusting color tone and imparting heat resistance. Examples of the zinc salt include zinc halide such as zinc chloride and zinc iodide, zinc sulfate, and zinc acetate.

The concentration of zinc ions in the zinc salt aqueous solution is, for example, 0.1 to 10% by weight, preferably 0.5 to 7% by weight. Further, the zinc salt solution preferably contains potassium ions such as potassium iodide and iodine ions. The potassium iodide concentration in the zinc salt solution is, for example, 0.1 to 10% by weight, preferably 0.2 to 5% by weight.

The zinc content in the polarizer is preferably 2.00% by weight or less, more preferably 1.00% by weight or less, preferably 0.03% by weight or more, and 0.05% by weight. % Or more is more preferable. When the zinc content of the polarizer is in the above range, it is easy to prevent the elution of iodine in a high temperature and high humidity environment. Zinc content is measured using a commercially available fluorescent X-ray analyzer. The zinc content can be controlled by metal ion treatment or the like.

The iodine content in the polarizer is preferably 3.3% by weight or less, more preferably 3.0% by weight or less, preferably 1.9% by weight or more, and 2.2% by weight. % Or more is more preferable. When the iodine content of the polarizer is in the above range, the amount of iodine that can be eluted can be reduced while maintaining good polarization performance. The iodine content is measured using a commercially available fluorescent X-ray analyzer. The iodine content can be controlled by a dyeing treatment, a cross-linking treatment, a washing treatment, or the like.

The thickness of the polarizer is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, and particularly preferably 8 μm or less. The thickness of the polarizer is usually 2 μm or more, preferably 3 μm or more. Reducing the thickness of the polarizer contributes to reducing the amount of iodine contained in the polarizer, so that the amount of iodine that can be eluted can be reduced. On the other hand, by ensuring a certain thickness, it is possible to improve the transportability of the film and secure the polarization performance of the obtained polarizing element.

The polarizer obtained in this manner preferably has a luminosity factor correction single transmittance of 50% or less, more preferably 45% or less, preferably 40% or more, and 42% or more. Is more preferable. When the visible sensitivity correction simple substance transmittance of the polarizer is within the above range, the amount of iodine that can be eluted can be reduced while maintaining good polarization performance.

The polarizer obtained in this manner preferably has a luminosity factor correction polarization degree of 99.999% or less, more preferably 99.995% or less, and preferably 99.985% or more. More preferably, it is 99.990% or more. When the luminosity factor correction degree of polarization of the polarizer is in the above range, the amount of iodine that can be eluted can be reduced while maintaining good polarization performance.

The elemental hue of the polarizer obtained in this manner preferably has an a * value of −0.90 or more and −0.60 or less, and more preferably −0.88 or more and −0.65 or less. Further, the b * value is 2.70 or more and 3.70 or less, and more preferably 2.80 or more and 3.60 or less. When the single hue of the polarizer is close to blue, that is, when the b * value is small, the retardation value of the retardation film tends to increase in a moist heat environment, so that the effect of the present invention is remarkable. The hue of the polarizer can be measured by a commercially available spectrophotometer.

(2) Protective Film The circularly polarizing plate of the present invention preferably has a protective film on at least one surface of the polarizer and a protective film on the surface of the polarizer opposite to the retardation film side. Polarizer comprises at least one protective film is moisture permeability ^50g / m 2 · 24hr or more. The moisture permeability of the protective film is measured by the method described later.

The protective film laminated on the polarizer can be a translucent (preferably optically transparent) thermoplastic resin. As the protective film, a polyolefin resin such as a chain polyolefin resin (polypropylene resin or the like) or a cyclic polyolefin resin (norbornen resin or the like); a cellulose resin such as triacetyl cellulose or diacetyl cellulose; polyethylene terephthalate, Polyester resin such as polybutylene terephthalate; Polycarbonate resin; (Meta) acrylic resin such as methyl methacrylate resin; Polystyrene resin; Polyvinyl chloride resin; Acrylonitrile, butadiene, styrene resin; Acrylonitrile, styrene Based resin; Polyvinyl acetate resin; Polyvinylidene chloride resin; Polyamide resin; Polyacetal resin; Modified polyphenylene ether resin; Polysulfone resin; Polyether sulfone resin; Polyallylate resin; Polyamiimide resin; Polyethylene Examples thereof include a film made of a based resin or the like.

As the chain polyolefin resin, polyethylene resin (polyethylene resin which is a homopolymer of ethylene or a copolymer mainly composed of ethylene), polypropylene resin (polypropylene resin which is a homopolymer of propylene or propylene as a main component) are used. In addition to homopolymers of chain olefins such as (copolymers), copolymers composed of two or more kinds of chain olefins can be mentioned.

Cyclic polyolefin resin is a general term for resins that are polymerized using cyclic olefins as a polymerization unit. Resin is mentioned. Specific examples of the cyclic polyolefin resin include an open (co) polymer of a cyclic olefin, an addition polymer of a cyclic olefin, and a copolymer of a cyclic olefin and a chain olefin such as ethylene and propylene (typically). Is a random copolymer), a graft polymer obtained by modifying these with an unsaturated carboxylic acid or a derivative thereof, and a hydride thereof. Of these, a norbornene-based resin using a norbornene-based monomer such as norbornene or a polycyclic norbornene-based monomer is preferably used as the cyclic olefin.

The polyester-based resin is a resin having an ester bond, excluding the following cellulose ester-based resin, and is generally composed of a polyvalent carboxylic acid or a polycondensate of a derivative thereof and a polyhydric alcohol. As the polyvalent carboxylic acid or a derivative thereof, a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylic acid. As the polyhydric alcohol, a divalent diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. A typical example of the polyester resin is polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol.

The (meth) acrylic resin is a resin containing a compound having a (meth) acryloyl group as a main constituent monomer. Specific examples of the (meth) acrylic resin include poly (meth) acrylic acid esters such as polymethyl methacrylate; methyl methacrylate- (meth) acrylic acid copolymers; methyl methacrylate- (meth) acrylic acid. Ester copolymer; methyl methacrylate-acrylic acid ester- (meth) acrylic acid copolymer; (meth) methyl acrylate-styrene copolymer (MS resin, etc.); methyl methacrylate and alicyclic hydrocarbon group It contains a copolymer with the compound (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate- (meth) norbornyl copolymer, etc.). _{Preferably, a polymer containing poly (meth) acrylic acid C 1-6} alkyl ester as a main component, such as methyl poly (meth) acrylate, is used, and more preferably, methyl methacrylate as a main component (50 to 100) is used. A methyl methacrylate-based resin having a weight of% by weight, preferably 70 to 100% by weight) is used.

Cellulose ester-based resins are esters of cellulose and fatty acids. Specific examples of the cellulose ester resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. In addition, these copolymers and those in which a part of the hydroxyl group is modified with another substituent can also be mentioned. Among these, cellulose triacetate (triacetyl cellulose) is particularly preferable.

Polycarbonate-based resin is an engineering plastic composed of a polymer in which monomer units are bonded via a carbonate group.

The thickness of the protective film is usually 1 to 100 μm, but is preferably 5 to 60 μm, more preferably 10 to 55 μm, and even more preferably 15 to 40 μm from the viewpoint of strength, handleability, and the like.

The protective film bonded to one side or both sides of the polarizer may be made of the same type of thermoplastic resin or may be made of a different type of thermoplastic resin. Further, the thickness may be the same or different. Further, it may have the same phase difference characteristic or may have different phase difference characteristics.

As described above, the phenomenon that the in-plane retardation value of the retardation film increases in a high temperature and high humidity environment occurs when moisture elutes iodine contained in the polarizer and the iodine is transferred to the retardation film. It is considered to be. Therefore, in a high-temperature and high-humidity environment, the effect of the present invention is remarkable when water easily penetrates into the polarizer and when iodine easily elutes from the polarizer. Examples of such an embodiment include a mode in which a protective film having high moisture permeability is laminated on the side opposite to the retardation film side of the polarizer, and a mode in which the protective film is not laminated on the retardation film side of the polarizer.

From this point of view, the moisture permeability of the protective film polarizers provided on the opposite side of the retardation film side, may also be ^50g / m 2 · 24hr or more, there is 100g ^/ m 2 · 24hr or more may be, it may be 500g ^/ m 2 · 24hr or more. Moisture permeability of the protective film can be, for example, less 1000g ^/ m 2 · 24hr. The moisture permeation is based on JIS Z 0208, and refers to a value measured at a temperature of 40 ° C. and a relative humidity of 90%.

Polarizer, if both surfaces of the polarizer comprising a protective film, the moisture permeability of one of the protective films, ^50g / m 2 · 24hr or more (or 100g ^/ m 2 · 24hr or more, further 500 g / ^{m 2} · when the above 24 hr or), the moisture permeability of the other protective film is preferably from 1000g ^/ m 2 · 24hr, more preferably at most ^{500g / m 2 · 24hr, 100g} / m 2 · more preferably 24hr or less, and particularly preferably not more than ^50g / m 2 · 24hr.

Polarizer, if a protective film on both surface of the polarizer, the moisture permeability 50g / m 2 ^· 24hr or more protective films arranged on the opposite side of the retardation film side of the polarizer (or 100 g / m ² · 24 hr or more, when the news was 500g ^/ m 2 · 24hr or more), the moisture permeability of the protective film to be disposed on the retardation film side of the polarizer is preferably from 1000g ^/ m 2 · 24hr, 500g / more preferably ^m is 2 · 24 hr or less, more preferably at most 100 g ^/ m 2 · 24 hr or, even more preferably at most ^{50 g} / m 2 · 24 hr or.

As described above, at least one of the protective films has a hard coat layer, an antiglare layer, a light diffusion layer, an antireflection layer, a low refractive index layer, and an antistatic layer on the outer surface (the surface opposite to the polarizer). It may be provided with a surface treatment layer (coating layer) such as an antifouling layer and an antifouling layer. The thickness of the protective film includes the thickness of the surface treatment layer. These surface-treated layers can contribute to preventing moisture from entering the polarizer.

The protective film can be attached to the polarizer via an adhesive layer or an adhesive layer described later. The adhesive forming the adhesive layer is preferably a water-based adhesive or an active energy ray-curable adhesive.

When the polarizer and the protective film are bonded, a surface activation treatment may be applied to at least one of these bonding surfaces in order to enhance the adhesiveness. Surface activation treatment includes dry treatment such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, ionization active ray treatment (ultraviolet ray treatment, electron beam treatment, etc.). Wet treatments such as ultrasonic treatment using a solvent such as water or acetone, ionization treatment, and anchor coating treatment can be mentioned. These surface activation treatments may be performed alone or in combination of two or more.

When the protective films are bonded to both sides of the polarizer, the adhesive for bonding these protective films may be the same type of adhesive or different types of adhesives.

Instead of the protective film, a protective layer may be formed on at least one surface of the polarizer. The protective layer can be formed on the polarizer without an adhesive layer or an adhesive layer, that is, the protective layer can be formed in contact with the polarizer. The protective layer can be a layer containing a (meth) acrylic resin. The protective layer can prevent the transfer of iodine from the polarizer. The protective layer may be a single layer or may be formed from a plurality of layers.

For the layer containing the (meth) acrylic resin, a composition containing the (meth) acrylic resin is applied to the polarizer and heated or irradiated with active energy rays, or the (meth) acrylic resin is placed on the base film. It can be formed by applying a composition containing the above-mentioned material and heating it or irradiating it with active energy rays. In the latter case, a polarizer may be formed on a layer containing a (meth) acrylic resin.

The (meth) acrylic resin means a polymer whose main component is a monomer having a (meth) acryloyl group among the monomers constituting the (meth) acrylic resin. Here, the main component refers to a monomer having the largest content (mass%) among the monomer components constituting the (meth) acrylic resin. By using a (meth) acrylic resin as a material for forming the protective layer, it is possible to suppress deterioration of the optical properties of the circularly polarizing plate even in a moist heat environment.

The (meth) acrylic resin is preferably one obtained by polymerizing a photopolymerizable monomer. For example, a monofunctional monomer or a polyfunctional monomer having a (meth) acryloyl group is polymerized alone or in combination of two or more. Can be what you did. In the (meth) acrylic resin, a monomer other than the monomer having a (meth) acryloyl group may be polymerized, and for example, a monomer having a vinyl group may be polymerized.

The monomer having a (meth) acryloyl group is not particularly limited, and examples thereof include compounds having one or two or more (meth) acryloyl groups in the molecule, and these may be used alone or in admixture of two or more. Can be used. Specifically, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate, ethylene oxide or propylene oxide of the above (meth) acrylate. Additive compound; oligoester (meth) acrylate having 4 or more (meth) acryloyl groups in the molecule, oligoether (meth) acrylate, oligourethane (meth) acrylate, oligoepoxy (meth) acrylate, oligomelamine (meth) Examples thereof include acrylates and polyfunctional acrylates having a dendrimer structure.

The thickness of the layer containing the (meth) acrylic resin is usually 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, and usually 20.0 μm or less. It is preferably 15 μm or less, and more preferably 10 μm or less.

<Phase difference film>
The circularly polarizing plate of the present invention has a retardation film. The retardation film has a retardation layer.
The retardation layer preferably has a layer composed of a composition containing a polymerizable liquid crystal compound.
The layer composed of the composition containing the polymerizable liquid crystal compound specifically means a layer in which the polymerizable liquid crystal compound is cured. In the present specification, a layer that gives a phase difference of λ / 2, a layer that gives a phase difference of λ / 4 (positive A layer), a positive C layer, and the like are collectively referred to as a retardation layer. Further, the retardation film preferably contains an alignment film described later.

The layer that gives the phase difference of λ / 2 preferably means a layer having an in-plane retardation value of 200 to 280 nm at a wavelength of 550 nm, and more preferably a layer having an in-plane retardation value of 215 to 265 nm. Means that. The layer that gives the phase difference of λ / 4 preferably means a layer having an in-plane retardation value of 100 to 160 nm at a wavelength of 550 nm, and more preferably a layer having an in-plane retardation value of 110 to 150 nm. Means that. The positive C layer can be a layer having a refractive index of nx≈ny <nz. The phase difference value in the thickness direction of the positive C layer can be −50 nm to −150 nm at a wavelength of 550 nm, and can be −70 nm to −120 nm. Note that nx is the refractive index in the direction in which the in-plane refractive index is maximized (that is, the slow-phase axis direction), and ny is the in-plane refraction in the direction orthogonal to the slow-phase axis (that is, the phase-advancing axis direction). It is a rate, and nz is a refractive index in the thickness direction.

The retardation layer may exhibit positive wavelength dispersibility or may exhibit reverse wavelength dispersibility. When the retardation film has a plurality of retardation layers, each retardation layer may exhibit positive wavelength dispersibility or reverse wavelength dispersibility. When the retardation film includes a retardation layer exhibiting anti-wavelength dispersibility, the reflected hue tends to change when the retardation value rises in a moist heat environment, and the visibility of the display device tends to deteriorate. Therefore, the effect of the present invention is remarkable when the retardation film includes a retardation layer exhibiting anti-wavelength dispersibility.

In the present invention, it is preferable that the layer giving the phase difference of λ / 4 has anti-wavelength dispersibility.
Specifically, the layer that gives a phase difference of λ / 4 preferably satisfies the following equation.
0.80 <Re (450) / Re (550) <1.00 ... (1)
1.00 <Re (650) / Re (550) <1.30 ... (2)
In the equation, Re (λ) represents an in-plane retardation value at a wavelength of λ nm.

The cured layer of the polymerizable liquid crystal compound is formed on, for example, an alignment film provided on the base material. The base material has a function of supporting the alignment film and may be a long base material. This substrate can function as a releasable support and support a retardation layer for transfer. Further, it is preferable that the surface has an adhesive force that can be peeled off. Examples of the base material include a resin film exemplified as a material for the protective film.

The thickness of the base material is not particularly limited, but is preferably in the range of, for example, 20 μm or more and 200 μm or less. When the thickness of the base material is 20 μm or more, strength is imparted. On the other hand, when the thickness is 200 μm or less, when the base material is cut to obtain a single-wafer base material, an increase in processing waste and wear of the cutting blade can be suppressed.

The base material may be subjected to various anti-blocking treatments. Examples of the blocking prevention treatment include an easy-adhesion treatment, a treatment in which a filler or the like is kneaded, an embossing treatment (knurling treatment), and the like. By applying such a blocking prevention treatment to the base material, it is possible to effectively prevent the base materials from sticking to each other when the base material is wound, so-called blocking, and to manufacture an optical film with high productivity. Is possible.

The cured layer of the polymerizable liquid crystal compound is formed on the substrate via the alignment film. That is, the base material and the alignment film are laminated in this order, and the layer on which the polymerizable liquid crystal compound is cured is laminated on the alignment film.

The alignment film may be a vertical alignment film, an alignment film for horizontally aligning the molecular axis of the polymerizable liquid crystal compound, or an alignment film for tilting the molecular axis of the polymerizable liquid crystal compound. good. The type of alignment film can be selected according to the polymerizable liquid crystal compound and the desired retardation characteristics. The alignment film has solvent resistance that does not dissolve due to coating of a composition containing a polymerizable liquid crystal compound, which will be described later, and heat resistance in heat treatment for removing the solvent and aligning the liquid crystal compound. preferable. Examples of the alignment film include an alignment film containing an orientation polymer, a photo-alignment film, and a grub alignment film that forms an uneven pattern or a plurality of grooves on the surface to align.

The thickness of the alignment film is usually in the range of 10 nm to 10000 nm, preferably in the range of 10 nm to 1000 nm, more preferably in the range of 500 nm or less, and further preferably in the range of 10 nm to 200 nm. When the retardation film contains an alignment film and the alignment film is arranged between the polarizer and the retardation layer, the alignment film can exert a function of blocking the transfer of iodine.
The thickness of the alignment film for sufficiently exerting the function of blocking the transfer of iodine is, for example, 0.3 μm or more, preferably 0.5 μm or more, more preferably 0.7 μm or more, still more preferable. Is 1.0 μm or more.

The alignment film containing the orientation polymer usually applies a composition in which the orientation polymer is dissolved in a solvent to the base material to remove the solvent, or applies the orientation polymer composition to the base material to remove the solvent. It is obtained by rubbing (rubbing method). Examples of the oriented polymer include polyamides and gelatins having an amide bond in the molecule, polyimide having an imide bond in the molecule and its hydrolyzate polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, and poly. Examples thereof include oxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylic acid esters. Of these, polyvinyl alcohol is preferable. The oriented polymer can be used alone or in combination of two or more.

The photoalignment film is usually obtained by applying a composition containing a polymer or monomer having a photoreactive group and a solvent to a substrate, removing the solvent, and then irradiating with polarized light (preferably polarized UV). The photoalignment film is also advantageous in that the direction of the orientation regulating force can be arbitrarily controlled by selecting the polarization direction of the polarized light to be irradiated.

A photoreactive group is a group that produces a liquid crystal alignment ability when irradiated with light. Specific examples thereof include groups involved in photoreactions that are the origin of liquid crystal orientation ability such as molecular orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction or photodecomposition reaction generated by light irradiation. Of these, groups involved in the dimerization reaction or photocrosslinking reaction are preferable because they are excellent in orientation. As the photoreactive group, an unsaturated bond, particularly a group having a double bond is preferable, and a carbon-carbon double bond (C = C bond), a carbon-nitrogen double bond (C = N bond), and a nitrogen-nitrogen double bond are preferable. A group having at least one selected from the group consisting of a double bond (N = N bond) and a carbon-oxygen double bond (C = O bond) is particularly preferable.

Examples of the photoreactive group having a C = C bond include a vinyl group, a polyene group, a stilbene group, a still bazol group, a still bazolium group, a chalcone group, a cinnamoyl group and the like. Examples of the photoreactive group having a C = N bond include a group having a structure such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N = N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C = O bond include a benzophenone group, a coumarin group, an anthraquinone group, a maleimide group and the like. These groups may have substituents such as an alkyl group, an alkoxy group, an allyl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group and an alkyl halide group.

Among them, a photoreactive group involved in the photodimerization reaction is preferable, and a photoalignment film having a relatively small amount of polarized light required for photoalignment and excellent thermal stability and stability over time can be easily obtained. A cinnamoyl group and a chalcone group are preferable. As the polymer having a photoreactive group, a polymer having a cinnamoyl group such that the terminal portion of the side chain of the polymer has a cinnamic acid structure is particularly preferable.

The polymerizable liquid crystal compound can be classified into a rod-shaped type (rod-shaped liquid crystal compound) and a disk-shaped type (disk-shaped liquid crystal compound, discotic liquid crystal compound) according to its shape. Further, there are a small molecule type and a high molecular type, respectively. The polymer generally refers to a polymer having a degree of polymerization of 100 or more (Polymer Physics / Phase Transition Dynamics, Masao Doi, 2 pages, Iwanami Shoten, 1992). In the present invention, any type of polymerizable liquid crystal compound can be used. Two or more kinds of rod-shaped liquid crystal compounds, two or more kinds of disk-shaped liquid crystal compounds, or a mixture of a rod-shaped liquid crystal compound and a disk-shaped liquid crystal compound may be used.

As the rod-shaped liquid crystal compound, for example, those described in claim 1 of JP-A-11-513019 or paragraphs [0026] to [0998] of JP-A-2005-289980 can be preferably used. .. As the disk-shaped liquid crystal compound, for example, those described in paragraphs [0020] to [0067] of JP-A-2007-108732 or paragraphs [0013] to [0108] of JP-A-2010-244038 are preferable. Can be used for.

Two or more kinds of polymerizable liquid crystal compounds may be used in combination. In that case, it is preferable that at least one type has two or more polymerizable groups in the molecule. That is, the cured layer of the polymerizable liquid crystal compound is preferably a layer formed by fixing a liquid crystal compound having a polymerizable group by polymerization. In this case, it is no longer necessary to exhibit liquid crystallinity after forming a layer.

The polymerizable liquid crystal compound has a polymerizable group capable of carrying out a polymerization reaction. As the polymerizable group, for example, a functional group capable of an addition polymerization reaction such as a polymerizable ethylenically unsaturated group or a ring-polymerizable group is preferable.
More specifically, examples of the polymerizable group include a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, the (meth) acryloyl group is preferable.

The cured layer of the polymerizable liquid crystal compound can be formed by applying a composition containing the polymerizable liquid crystal compound onto, for example, an alignment film and irradiating it with active energy rays. The composition may contain components other than the above-mentioned polymerizable liquid crystal compound. The composition preferably contains a polymerization initiator. As the polymerization initiator used, for example, a thermal polymerization initiator or a photopolymerization initiator is selected according to the type of the polymerization reaction. For example, examples of the photopolymerization initiator include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, and combinations of triarylimidazole dimers and p-aminophenyl ketones. The amount of the polymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the total solid content in the composition.

The composition may contain a polymerizable monomer from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Among them, a polyfunctional radically polymerizable monomer is preferable.

The polymerizable monomer is preferably one that can be copolymerized with the above-mentioned polymerizable liquid crystal compound. The amount of the polymerizable monomer used is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, based on the total mass of the polymerizable liquid crystal compound.

The composition may contain a surfactant in terms of the uniformity of the coating film and the strength of the film.
Examples of the surfactant include conventionally known compounds. Among them, fluorine-based compounds are particularly preferable.

The composition can contain a solvent, preferably an organic solvent. Organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, chloroform). , Dichloromethane), esters (eg, methyl acetate, ethyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Among them, alkyl halides and ketones are preferable. The composition may contain two or more kinds of organic solvents.

The composition includes various vertical alignment promoters such as a polarizer interface side vertical alignment agent and an air interface side vertical alignment agent, and a horizontal alignment accelerator such as a polarizer interface side horizontal alignment agent and an air interface side horizontal alignment agent. Aligners can be included. Further, the composition may contain an adhesion improver, a plasticizer, and a polymer in addition to the above components.

The active energy rays include ultraviolet rays, visible light, electron beams, and X-rays, and are preferably ultraviolet rays. Examples of the light source of the active energy ray include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excima laser, and a wavelength range. Examples thereof include an LED light source that emits 380 to 440 nm, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

The irradiation intensity of ultraviolet light is, for example, ^{100mW / cm 2 ~3,000mW / cm 2} . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating the cationic polymerization initiator or the radical polymerization initiator. The time for irradiating with ultraviolet rays is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, and even more preferably 0.1 seconds. ~ 1 minute. Ultraviolet rays can be irradiated once or in a plurality of times.

In the present embodiment, the thickness of the retardation layer is preferably 0.5 μm or more. The thickness of the retardation layer is preferably 10 μm or less, and more preferably 5 μm or less. The above-mentioned upper limit value and lower limit value can be arbitrarily combined. When the thickness of the retardation layer is at least the above lower limit value, sufficient durability can be obtained. When the thickness of the retardation layer is not more than the upper limit value, it can contribute to the thinning of the circularly polarizing plate. As the thickness of the retardation layer, a desired in-plane retardation value of a layer giving a retardation of λ / 4, a layer giving a retardation of λ / 2, or a positive C layer, and a retardation value in the thickness direction can be obtained. Can be adjusted.

The retardation film may include one layer in which the polymerizable liquid crystal compound is cured, or may include two or more layers in which the polymerizable liquid crystal compound is cured. When the retardation film contains two layers in which the polymerizable liquid crystal compound is cured, the two layers are a layer giving a phase difference of λ / 4 and a positive C layer, or a layer giving a retardation of λ / 4 and λ / 2. It is preferable that the layer gives a phase difference of. When the retardation film contains two layers in which the polymerizable liquid crystal compound is cured, the layers in which the polymerizable liquid crystal compound is cured are prepared on the alignment film, and the two are laminated via an adhesive layer to obtain a retardation. The film may be produced, or a layer on which the polymerizable liquid crystal compound is further cured may be formed on the layer on which the polymerizable liquid crystal compound is cured. After laminating both, the base material can be peeled off leaving the alignment film, and both the alignment film and the base material can be peeled off.

From the viewpoint of preventing the transfer of iodine, it is preferable that the polymerizable liquid crystal compound has an alignment film between the cured layer and the polarizer. The alignment film can also serve to prevent iodine from entering the cured layer of the polymerizable liquid crystal compound. Therefore, when the retardation film contains one layer in which the polymerizable liquid crystal compound is cured, in the retardation film, the alignment film and the layer in which the polymerizable liquid crystal compound is cured are laminated in this order from the side closer to the polarizer. It is preferable that the configuration is as follows. When the retardation film contains two layers in which the polymerizable liquid crystal compound is cured, the retardation film is an alignment film, a layer in which the polymerizable liquid crystal compound is cured, an adhesive layer, and a polymerizable liquid crystal compound from the side closer to the polarizer. The cured layer and the alignment film are laminated in this order. From the side closer to the polarizer, the alignment film, the layer on which the polymerizable liquid crystal compound is cured, the alignment film, and the layer on which the polymerizable liquid crystal compound is cured are the layers. It is preferable that the configurations are laminated in order.

The thickness of the retardation film is preferably 3 to 30 μm, more preferably 5 to 25 μm.

<Adhesive layer>
Examples of the adhesive layer include an adhesive layer and an adhesive layer described later. As the adhesive layer, a polarizer and a protective film are laminated, a polarizing plate and a retardation film are laminated, two retardation layers are laminated, and a circular polarizing plate is laminated on an image display element or a touch sensor. It can be a layer to do.

From the viewpoint of preventing the transfer of iodine, the adhesive layer for laminating the polarizing plate and the retardation film is preferably an adhesive layer, and more preferably an active energy ray-curable adhesive layer. The thickness of the adhesive layer on which the polarizing plate and the retardation film are laminated is preferably 1.0 μm or more, more preferably 1.5 μm or more, and further preferably 2.0 μm or more.

<Adhesive layer>
The pressure-sensitive adhesive layer can be composed of a pressure-sensitive adhesive composition containing a resin as a main component, such as (meth) acrylic-based, rubber-based, urethane-based, ester-based, silicone-based, and polyvinyl ether-based.
Among them, a pressure-sensitive adhesive composition using a (meth) acrylic resin having excellent transparency, weather resistance, heat resistance and the like as a base polymer is preferable. The pressure-sensitive adhesive composition may be an active energy ray-curable type or a thermosetting type. The thickness of the pressure-sensitive adhesive layer is usually 3 to 30 μm, preferably 3 to 25 μm.

Examples of the (meth) acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2- (meth) acrylate. A polymer or copolymer containing one or more (meth) acrylic acid esters such as ethylhexyl as a monomer is preferably used. It is preferable that the base polymer is copolymerized with a polar monomer. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl (). Examples thereof include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as meta) acrylate.

The pressure-sensitive adhesive composition may contain only the above-mentioned base polymer, but usually further contains a cross-linking agent. The cross-linking agent is a divalent or higher metal ion that forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound that forms an amide bond with a carboxyl group; poly. Epoxy compounds and polyols that form an ester bond with a carboxyl group; polyisocyanate compounds that form an amide bond with a carboxyl group are exemplified. Of these, polyisocyanate compounds are preferable.

<Adhesive layer>
Examples of the water-based adhesive include an adhesive composed of a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. Of these, a water-based adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin is preferably used. Examples of the polyvinyl alcohol-based resin include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, and co-polymers of vinyl acetate and other monomers copolymerizable therewith. A polyvinyl alcohol-based copolymer obtained by saponifying the polymer, or a modified polyvinyl alcohol-based polymer in which the hydroxyl groups thereof are partially modified can be used. The water-based adhesive may contain a cross-linking agent such as an aldehyde compound (glioxal or the like), an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, or a polyvalent metal salt.

When a water-based adhesive is used, it is preferable to carry out a drying step for removing water contained in the water-based adhesive after laminating the members. After the drying step, a curing step of curing at a temperature of, for example, 20 to 45 ° C. may be provided.

The active energy ray-curable adhesive is an adhesive containing a curable compound that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, and is preferably an ultraviolet curable adhesive. Is.

The curable compound can be a cationically polymerizable curable compound or a radically polymerizable curable compound. The cationically polymerizable curable compound includes an epoxy compound (a compound having one or more epoxy groups in the molecule) and an oxetane compound (having one or two or more oxetane rings in the molecule). Compound), or a combination thereof. Examples of the radically polymerizable curable compound include (meth) acrylic compounds (compounds having one or more (meth) acryloyloxy groups in the molecule) and other radically polymerizable double bonds. Vinyl compounds or combinations thereof can be mentioned. A cationically polymerizable curable compound and a radically polymerizable curable compound may be used in combination. The active energy ray-curable adhesive usually further contains a cationic polymerization initiator and / or a radical polymerization initiator for initiating the curing reaction of the curable compound.

<Front plate>
The present invention includes a circularly polarizing plate with a front plate in which a circularly polarizing plate and a front plate are laminated via an adhesive layer.
The front plate is arranged on the visible side of the polarizing plate. The front plate can be laminated on the polarizing plate via the adhesive layer. Examples of the adhesive layer include the above-mentioned adhesive layer and adhesive layer. As shown in FIGS. 2A, 2B, and 2C, the front plate 4 can be laminated on the protective film 11 in the polarizing plate 1 via the adhesive layer 16.

Examples of the front plate include those having a hard coat layer on at least one surface of glass or a resin film. As the glass, for example, highly transparent glass or tempered glass can be used. Especially when a thin transparent surface material is used, chemically strengthened glass is preferable. The thickness of the glass can be, for example, 100 μm to 5 mm.

The front plate, which includes a hard coat layer on at least one surface of the resin film, can have a flexible property rather than being rigid like existing glass. The thickness of the hard coat layer is not particularly limited and may be, for example, 5 to 100 μm.

As the resin film, cycloolefin-based derivatives having a unit of a monomer containing cycloolefin such as norbornene or polycyclic norbornene-based monomer, cellulose (diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, isobutyl ester cellulose). , Propionyl cellulose, butyryl cellulose, acetylpropionyl cellulose) ethylene-vinyl acetate copolymer, polycycloolefin, polyester, polystyrene, polyamide, polyetherimide, polyacrylic, polyimide, polyamideimide, polyethersulfone, polysulfone, polyethylene, Polypropylene, Polymethylpentene, Polyvinyl Chloride, Polyvinylidene Chloride, Polyvinyl Alcohol, Polyvinyl Acetate, Polyether Ketone, Polyether Ether Ketone, Polyether Sulfone, Polymethyl Metalacrylate, Polyethylene Telephthalate, Polybutylene Telephthalate, Polyethylene Naphthalate, Polycarbonate , Polyethylene, a film made of a polymer such as epoxy. As the resin film, an unstretched uniaxial or biaxially stretched film can be used. Each of these polymers can be used alone or in combination of two or more. As the resin film, a polyamideimide film or a polyimide film having excellent transparency and heat resistance, a uniaxial or biaxially stretched polyester film, a cycloolefin derivative film having excellent transparency and heat resistance and capable of adapting to a large size of the film. , Polymethylmethacrylate films and triacetylcellulose and isobutylester cellulose films that are transparent and not optically anisotropic are preferred. The thickness of the resin film may be 5 to 200 μm, preferably 20 to 100 μm.

The hard coat layer can be formed by curing a hard coat composition containing a reactive material that is irradiated with light or heat energy to form a crosslinked structure. The hard coat layer can be formed by curing a hard coat composition containing a photocurable (meth) acrylate monomer, or an oligomer and a photocurable epoxy monomer, or an oligomer at the same time. The photocurable (meth) acrylate monomer may contain one or more selected from the group composed of epoxy (meth) acrylate, urethane (meth) acrylate and polyester (meth) acrylate. The epoxy (meth) acrylate can be obtained by reacting an epoxy compound with a carboxylic acid having a (meth) acryloyl group.

The hard coat composition may further comprise one or more selected from the group consisting of solvents, photoinitiators and additives. Additives can include one or more selected from the group consisting of inorganic nanoparticles, leveling agents and stabilizers, and other components commonly used in the art, such as anti. Excipients, UV absorbers, surfactants, lubricants, antifouling agents and the like can be further included.

<Shading pattern>
The shading pattern can be provided as at least part of the front plate or the bezel or housing of the display device to which the front plate is applied. The light-shielding pattern can be formed on the display element side of the front plate. The shading pattern can hide each wiring of the display device so that it cannot be seen by the user. The color and / or material of the light-shielding pattern is not particularly limited, and can be formed of a resin substance having various colors such as black, white, and gold.
In one embodiment, the thickness of the shading pattern may be 2 μm to 50 μm, preferably 4 μm to 30 μm, and more preferably 6 μm to 15 μm. Further, in order to suppress the mixing of air bubbles due to the step between the light-shielding pattern and the display unit and the visibility of the boundary portion, the light-shielding pattern can be given a shape.

<Manufacturing method of circularly polarizing plate>
A method for manufacturing a circularly polarizing plate will be described by taking the circularly polarizing plate 100 shown in FIG. 1A as an example. The circularly polarizing plate 100 can be manufactured by laminating the polarizing plate 1 and the retardation film 2 via the pressure-sensitive adhesive layer 13.

The polarizing plate 1 can be manufactured by laminating the polarizing element 10 and the protective films 11 and 12 via an adhesive layer, respectively. The polarizing plate may be manufactured by preparing long members, laminating the respective members by roll-to-roll, and then cutting them into a predetermined shape, or cutting each member into a predetermined shape. After that, they may be pasted together. After the protective films 11 and 12 are attached to the polarizer 10, a heating step and a humidity control step may be provided.

The retardation film 2 can be manufactured, for example, as follows. An alignment film is formed on the base material, and a coating liquid containing a polymerizable liquid crystal compound is applied onto the alignment film. With the polymerizable liquid crystal compound oriented, the polymerizable liquid crystal compound is cured by irradiating it with active energy rays. The pressure-sensitive adhesive layer 14 formed on the release film is laminated on the layer on which the polymerizable liquid crystal compound is cured. Then, the base material and / or the alignment film is peeled off. Next, the pressure-sensitive adhesive layer 13 formed on the release film is laminated on the protective film 12. The retardation film 2 may be manufactured by preparing long members, laminating the members by roll-to-roll, and then cutting the members into a predetermined shape, or forming each member into a predetermined shape. After cutting, they may be pasted together.

Then, the circularly polarizing plate 100 can be produced by peeling off the release film laminated on the pressure-sensitive adhesive layer 13 and laminating the retardation film 2 and the polarizing plate 1 via the pressure-sensitive adhesive layer 13. ..

<Use>
The circularly polarizing plate can be used in various display devices. The display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. Examples of the display device include a liquid crystal display device, an organic EL display device, an inorganic electroluminescence (hereinafter, also referred to as inorganic EL) display device, an electron emission display device (for example, an electric field emission display device (also referred to as FED), and a surface electric field emission display. Device (also called SED)), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection type display device (for example, grating light valve (GLV) display device, digital micromirror device (DMD)) (Also referred to as), a piezoelectric ceramic display, and the like. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, and the like. These display devices include a two-dimensional image. It may be a display device for displaying a three-dimensional image, or a three-dimensional display device for displaying a three-dimensional image. The circular polarizing plate can be particularly effectively used for an organic EL display device or an inorganic EL display device. ..

The display device of the present invention includes the circularly polarizing plate of the present invention and a display element. Examples of the display device of the present invention include those shown in FIG. In FIGS. 2A, 2B, and 2C, the organic EL display devices 104, 105, and 106 display the organic EL on the circularly polarizing plate via the adhesive layer 14 laminated on the retardation film 20. It has a layered structure laminated on the element 3.

[Boron content]
0.2 g of the polarizer was dissolved in 200 g of a 1.9 wt% mannitol aqueous solution. The obtained aqueous solution was titrated with a 1 mol / L sodium hydroxide aqueous solution, and the boron content of the polarizer was calculated by comparing the amount of the sodium hydroxide solution required for neutralization with the calibration curve.

[Phase difference value]
The retardation values of the circularly polarizing plate and the retardation film were measured using a retardation measuring device (KOBRA-WPR manufactured by Oji Measuring Instruments Co., Ltd.).

[Hue evaluation]
When measuring the reflected hue, MIRO (5011GP) manufactured by ALANOD was used as the reflector. This reflector is a mirror surface reflector having a reflecting surface formed by vapor deposition.

The evaluation sample was placed on the reflector. The reflected hue (a *, b *) was measured using a spectrophotometer (CM-2600d manufactured by Konica Minolta Co., Ltd.). The reflected hue is a value when the light source is D65, and was measured by the SCI method (including specular reflected light).

[Luminosity factor correction single transmittance, visibility correction polarization degree, single hue]
Luminosity factor correction single transmittance, luminosity factor correction polarization degree and single hue are JIS Z 8701 with respect to the transmittance and polarization degree obtained by using an absorptiometer with an integrating sphere (V7100 manufactured by JASCO Corporation). It was calculated by correcting the luminosity factor with a two-degree field of view (C light source).

[Measurement of moisture permeability]
The moisture permeability (water vapor permeability) of the protective film is measured under the condition of 40 ° C. and 90% RH based on the method described in JIS Z 0208, and is the value of the moisture permeability per 1 ^{m 2 per day (24 hours).} It was determined as ^{(g / m 2 · 24hr)} .

[Shrinkage stress]
A measurement sample having a width of 2 mm and a length of 10 mm having a long side in the absorption axis direction was cut out from the protective film of the polarizing plate. This sample is set in a thermomechanical analyzer (EXSTAR-6000 manufactured by SII Nanotechnology Co., Ltd.), and the absorption axis direction (long side direction) that occurs when the sample is held at 80 ° C. for 4 hours while keeping the dimensions constant. ), The contraction stress was measured.

[Example 1]
[Manufacturing Example 1: Fabrication of a laminated body including the retardation layer 1]
A composition for forming a horizontal alignment film is obtained by mixing 5 parts (weight average molecular weight: 30,000) of a photooriented material having the following structure and 95 parts of cyclopentanone, and stirring the obtained mixture at 80 ° C. for 1 hour. I got something.

1.0 part of the leveling agent (F-556; manufactured by DIC Corporation) was added to 100 parts of the mixture of the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B shown below at a mass ratio of 90:10. And 6 parts of 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one (“Irgacure 369 (Irg369)”, manufactured by BASF Japan KK), which is a polymerization initiator, was added.

Further, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration was 13%, and the mixture was stirred at 80 ° C. for 1 hour to obtain a retardation layer forming composition (1).

The polymerizable liquid crystal compound A was produced by the method described in JP-A-2010-31223.
Further, the polymerizable liquid crystal compound B was produced according to the method described in JP-A-2009-173893. The molecular structure of each is shown below.

(Polymerizable liquid crystal compound A)

(Polymerizable liquid crystal compound B)

A base film made of a cycloolefin polymer (COP) film (ZF-14, manufactured by Nippon Zeon Corporation, thickness 23 μm) was produced using a corona treatment device (AGF-B10, manufactured by Kasuga Electric Works Ltd.) at an output of 0.3 kW. Corona treatment was performed once under the condition of a treatment speed of 3 m / min. The composition for forming a horizontal alignment film was applied to the surface of the corona-treated substrate by a bar coater.
The coating film was dried at 80 ° C. for 1 minute, and polarized UV exposure was performed using a polarized UV irradiator (SPOT CURE SP-7; manufactured by Ushio Denki Co., Ltd.) with ^{an integrated light intensity of 100 mJ / cm 2.} The thickness of the obtained horizontal alignment film was measured with a laser microscope (LEXT, manufactured by Olympus Corporation) and found to be 100 nm.

Subsequently, the composition for forming a retardation layer (1) was passed through a PTFE membrane filter (manufactured by Advantech Toyo Co., Ltd., product number; T300A025A) having a pore size of 0.2 μm in an environment of room temperature of 25 ° C. and humidity of 30% RH. It was applied using a bar coater on a base film with an alignment film kept at 25 ° C. After the coating film is dried at 120 ° C. for 1 minute, it is irradiated with ultraviolet rays using a high-pressure mercury lamp (UNICURE VB-15201BY-A, manufactured by Ushio Denki Co., Ltd.) (in a nitrogen atmosphere, wavelength: 365 nm, integrated light intensity at wavelength 365 nm). : 1000 mJ / cm ² ) to produce an optical film. The thickness of the obtained coating film was measured with a laser microscope (LEXT, manufactured by Olympus Corporation) and found to be 2 μm.

In this way, a laminated body in which the layer in which the polymerizable liquid crystal compound was cured (the retardation layer 1), the horizontal alignment film, and the base film were laminated in this order was obtained. The retardation layer 1 was a retardation layer showing a retardation value of λ / 4. The retardation layer 1 showed anti-wavelength dispersibility.

[Manufacturing Example 2: Fabrication of Laminated Body Containing Phase Difference Layer 2]
As a composition for forming a vertically oriented film, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate, and bis (2-vinyloxyethyl) ether are mixed in a ratio of 1: 1: 4: 5. A mixture was mixed and LUCIRIN TPO was added as a polymerization initiator at a ratio of 4%.

The retardation layer forming composition (2) was prepared by preparing a photopolymerizable nematic liquid crystal compound (manufactured by Merck & Co., Inc., RMM28B) and a solvent so that the solid content was 1 to 1.5 g. As the solvent, a mixed solvent was used in which methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) were mixed at a mass ratio (MEK: MIBK: CHN) of 35:30:35.

A polyethylene terephthalate (PET) film having a thickness of 38 μm was prepared as a base film. A composition for forming a vertical alignment film was applied to one side of the base film so as to have a thickness of 3 μm, and ^{an ultraviolet ray of 200 mJ / cm 2} was irradiated to prepare a vertical alignment film.

The composition for forming a retardation layer (2) was coated on the vertically oriented layer by die coating.
The coating amount was 4 to 5 g (wet). The coating film was dried with a drying temperature of 75 ° C. and a drying time of 120 seconds. Then, the coating film was irradiated with ultraviolet rays (UV) to polymerize the polymerizable liquid crystal compound.

In this way, a laminated body in which the layer in which the polymerizable liquid crystal compound was cured (the retardation layer 2), the vertical alignment film, and the base film were laminated in this order was obtained. The retardation layer 2 was a positive C plate. The total thickness of the retardation layer 2 and the alignment film was 4 μm.

[Manufacturing Example 3: Fabrication of Laminated Phase Difference Layer]
The laminated body including the retardation layer 1 and the laminated body including the retardation layer 2 are bonded to each other by using an ultraviolet curable adhesive on the retardation layer surface (the surface opposite to the surface on the base film side). It was pasted together so that Then, the ultraviolet curable adhesive was cured by irradiating with ultraviolet rays. In this way, a laminate of retardation layers including the two retardation layers of the retardation layer 1 and the retardation layer 2 was produced.

[Manufacturing Example 4: Fabrication of Polarizer]
A polyvinyl alcohol film having a thickness of 20 μm, a degree of polymerization of 2,400, and a saponification degree of 99.9% or more was uniaxially stretched at a draw ratio of 4.5 times by a dry method, and iodine was 0 per 100 parts by weight of water while maintaining a tense state. It was immersed in a dyeing bath containing 0.05 parts by weight and 5 parts by weight of potassium iodide at 28 ° C. for 60 seconds.

Then, it was immersed in an aqueous boric acid solution 1 containing 5.5 parts by weight of boric acid and 15 parts by weight of potassium iodide per 100 parts by weight of water at 64 ° C. for 110 seconds. Then, it was immersed in an aqueous boric acid solution 2 containing 5.5 parts by weight of boric acid and 15 parts by weight of potassium iodide per 100 parts by weight of water at 67 ° C. for 30 seconds. Then, it was washed with pure water at 3 ° C. and dried to obtain a polarizer.

The luminosity factor-corrected single transmittance of the obtained polarizing element was 42.15%, and the luminosity factor-corrected polarization degree was 99.995%. The elemental hue a * of the polarizer was −0.88, and the elemental hue b * was 3.69. The contractile stress of the polarizer was 99.9 N / mm ² .

[Manufacturing Example 5: Fabrication of Polarizing Plate]
A saponified triacetyl cellulose (TAC) film 1 (KC2UATAC thickness 25 μm manufactured by Konica Minolta Co., Ltd.) was attached to one surface of the obtained polarizer with a nip roll via an aqueous adhesive. A saponified triacetyl cellulose (TAC) film 2 (ZRG20SL manufactured by FUJIFILM Corporation, thickness 20 μm) was attached to the other surface of the polarizer in the same manner as the TAC film 1. While maintaining the tension of the obtained laminate at 430 N / m, it was dried at 60 ° C. for 2 minutes to obtain a polarizing plate having TAC films on both sides of the polarizer. The water-based adhesive consists of 100 parts of water, 3 parts of carboxy group-modified polyvinyl alcohol (Kuraray Poval KL318 manufactured by Kuraray Co., Ltd.) and a water-soluble polyamide epoxy resin (Sumirace Resin 650 manufactured by Taoka Chemical Industry Co., Ltd.) with a solid content concentration of 30%. (Aqueous solution) 1.5 parts was added to prepare. Moisture permeability of TAC film 1 was 1200g ^/ m 2 · 24hr. Moisture permeability of TAC film 2 was 1500g ^/ m 2 · 24hr.

An acrylic pressure-sensitive adhesive layer was laminated on two TAC films of the polarizing plate. The base film used for forming the retardation layer 1 was peeled off from the laminate of the retardation layers produced in Production Example 3. The exposed horizontal alignment film and the acrylic pressure-sensitive adhesive layer were bonded together. The angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer 1 was 45 °. Next, the base film used for forming the retardation layer 2 was peeled off, and an acrylic pressure-sensitive adhesive layer was laminated on the exposed vertical alignment film.

In this way, a circularly polarizing plate in which a polarizing plate and a retardation film were laminated was obtained. In the circular polarizing plate, a TAC film 1, a polarizer, a TAC film 2, an adhesive layer, a horizontal alignment film, a retardation layer 1, an adhesive layer, a retardation layer 2, a vertically alignment film, and an adhesive layer are laminated in this order. It was a layered structure.

[Example 2]
A circularly polarizing plate was produced in the same manner as in Example 1 except that the TAC film 1 was bonded only to one side of the polarizing element when the polarizing plate was produced. The circularly polarizing plate has a layer structure in which a TAC film 1, a polarizer, an adhesive layer, a horizontally aligned film, a retardation layer 1, an adhesive layer, a retardation layer 2, a vertically aligning film, and an adhesive layer are laminated in this order. Met.

[Example 3]
A circularly polarizing plate was produced in the same manner as in Example 2 except that the boric acid content of the boric acid aqueous solution 2 was changed to 2.3 parts by weight when the polarizer was produced. The contractile stress of the polarizer was 88.2 N / mm ² . The luminosity factor-corrected single transmittance of the obtained polarizing element was 42.85%, and the luminosity factor-corrected polarization degree was 99.985%. The elemental hue a * of the polarizer was −0.69, and the elemental hue b * was 2.81.

[Example 4]
A circularly polarizing plate was produced in the same manner as in Example 2 except that the boric acid content of the boric acid aqueous solution 2 was changed to 1.8 parts by weight when the polarizer was produced. The contractile stress of the polarizer was 80.2 N / mm ² . The luminosity factor-corrected single transmittance of the obtained polarizer was 42.56%, and the luminosity factor-corrected polarization degree was 99.993%. The elemental hue a * of the polarizer was −0.81, and the elemental hue b * was 3.17.

[Example 5]
A circularly polarizing plate was produced in the same manner as in Example 2 except that the boric acid content of the boric acid aqueous solution 2 was changed to 1.1 parts by weight when the polarizer was produced. The contractile stress of the polarizer was 63.2 N / mm ² . The luminosity factor-corrected single transmittance of the obtained polarizer was 42.30%, and the luminosity factor-corrected polarization degree was 99.994%. The elemental hue a * of the polarizer was −0.90, and the elemental hue b * was 3.25.

[Example 6]
A polarizing plate was produced in the same manner as in Example 4.
An acrylic pressure-sensitive adhesive layer was laminated on the surface of the polarizer of the polarizing plate. Among the laminates containing the retardation layer 1 produced in Production Example 1, the retardation layer 1 and the acrylic pressure-sensitive adhesive layer were bonded together. The angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer 1 was 45 °.
After bonding, the base film used for forming the retardation layer 1 was peeled off. The exposed horizontal alignment film and the retardation layer 2 produced in Production Example 2 were bonded together with an ultraviolet curable adhesive. Then, the ultraviolet curable adhesive was cured by irradiating with ultraviolet rays. Next, the base film used for forming the retardation layer 2 was peeled off, and an acrylic pressure-sensitive adhesive layer was laminated on the exposed vertical alignment film.
In this way, a circularly polarizing plate in which a polarizing plate and a retardation film were laminated was obtained. The circularly polarizing plate has a layer structure in which a TAC film 1, a polarizer, an adhesive layer, a retardation layer 1, a horizontally aligned film, an adhesive layer, a retardation layer 2, a vertically aligned film, and an adhesive layer are laminated in this order. Met.

[Example 7]
A laminate containing a retardation layer was produced in the same manner as in Production Example 1 except that the integrated amount of ultraviolet rays irradiated when curing the polymerizable liquid crystal compound was 1500 mJ / cm ^2.
A circularly polarizing plate was produced in the same manner as in Example 3 except that the retardation layer 1 was changed to the retardation layer.

[Example 8]
A laminate containing a retardation layer was produced in the same manner as in Production Example 1 except that the integrated amount of ultraviolet rays irradiated when curing the polymerizable liquid crystal compound was 700 mJ / cm ^2.
A circularly polarizing plate was produced in the same manner as in Example 3 except that the retardation layer 1 was changed to the retardation layer.

[Comparative Example 1]
A circularly polarizing plate was produced in the same manner as in Example 2 except that the boric acid content of the boric acid aqueous solution 2 was changed to 0.7 parts by weight when the polarizer was produced.
The contractile stress of the polarizer was 26.2 N / mm ² . The luminosity factor-corrected single transmittance of the obtained polarizing element was 42.35%, and the luminosity factor-corrected polarization degree was 99.994%. The elemental hue a * of the polarizer was −1.00, and the elemental hue b * was 3.35.

The circularly polarizing plates produced in Examples and Comparative Examples were cut into a size of 150 mm × 50 mm using a super cutter, and bonded to a glass plate via an acrylic pressure-sensitive adhesive layer. The circularly polarizing plate bonded to the glass was placed in an oven having a temperature of 85 ° C. and a relative humidity of 85% RH for 24 hours. Table 1 shows the amount of change in the phase difference value and the amount of change in the reflected hue before and after putting in the oven.

According to the present invention, it is possible to provide a circularly polarizing plate in which the retardation value of the retardation film does not easily increase even when placed in a high temperature and high humidity environment, which is useful.

1 Polarizing plate 2 Phase difference film 3 Organic EL display element 4 Front plate 10 Polarizer 11, 12 Protective film 13, 14, 16 Adhesive layer 15 Adhesive layer 20, 21 Layers 100, 101, 103 on which the polymerizable liquid crystal compound is cured Circularly polarizing plate 104, 105, 106 Organic EL display device

Claims (10)

A circularly polarizing plate having a polarizing plate and a retardation film.
The polarizing plate includes a polarizing element and a protective film attached to at least one surface of the polarizing element.
The polarizer is a film in which iodine is adsorbed and oriented on a polyvinyl alcohol-based resin film.
The boron content of the polarizer is 1.00% by weight or more.
Moisture permeability of the protective film is a ^50g / m 2 · 24hr or more,
The retardation film is a circularly polarizing plate including a retardation layer composed of a layer obtained by curing a polymerizable liquid crystal compound. The circularly polarizing plate according to claim 1, wherein the thickness of the polarizer is 20 μm or less. The circular polarizing plate according to claim 1 or 2, wherein the visual sensitivity correction single-unit transmittance of the polarizer is 40% or more. The circularly polarizing plate according to any one of claims 1 to 3, wherein the contraction stress in the absorption axis direction per width of 2 mm is 60 N / mm ^{2 or more when the polarizer is held at 80 ° C. for 4 hours.} The elemental hue of the polarizer according to any one of claims 1 to 4, wherein the a * value is −0.90 or more and −0.60 or less, and the b * value is 2.70 or more and 3.70 or less. Circularly polarized light. The retardation film includes an alignment film and contains an alignment film.
The circular polarizing plate according to any one of claims 1 to 5, wherein the alignment film is located between the polarizer and the retardation layer. The circularly polarizing plate according to any one of claims 1 to 6, wherein the polarizing plate and the retardation film are bonded together with an active energy ray-curable adhesive. The polarizing plate is provided with protective films on both sides of the polarizer.
Moisture permeability of one of the protective film is a 500g ^/ m 2 · 24hr or more,
The moisture permeability of the other protective film, a circular polarizing plate according to claim 1 or less 100g ^/ m 2 · 24hr. The circularly polarizing plate according to any one of claims 1 to 8, further comprising a front plate, a light-shielding pattern, and a touch sensor. A display device including the circularly polarizing plate according to any one of claims 1 to 9 and a display element.

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