JPWO2018168306A1 - Polarizing plate and display device having the same - Google Patents

Abstract

The present invention uses a polyester resin film and a cycloolefin resin film or an acrylic resin film as a polarizer protective film, and in a polarizing plate having an ultraviolet ray cut function, reduces failure at the time of punching out a deformed shape of the polarizing plate, And a means for improving the adhesion between the polarizer protective film and the polarizer after aging. The present invention has a laminated structure in which a hard coat layer, a polyester resin film, a polarizer, a cycloolefin resin film or an acrylic resin film are laminated in this order, the hard coat layer, and the cycloolefin resin film Alternatively, the present invention relates to a polarizing plate, wherein the acrylic resin film contains an ultraviolet absorber, and the polyester resin film contains substantially no ultraviolet absorber. [Selection diagram] FIG.

Description

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

  Display devices are widely used for monitors of personal computers and portable devices, and for television applications. In recent years, particularly for in-vehicle applications, a display device that emphasizes design has been demanded. In a vehicle application, instead of a conventional rectangle, a display having a free shape such as a shape with rounded corners, a shape with a complicated curved surface, or a shape with a hole in the center may be used. Such a free-form display is called a deformed panel or a free-form display (FFD), and is considered to be used for an automobile meter or the like. As an example of the odd-shaped panel, there is a display shaped like a curve of an analog meter as shown in FIG. 1 described later.

  In general, a polarizing plate is made of a polarizer prepared by immersing a surface of a polarizer protective film facing a polarizer appropriately surface-treated on a side facing the polarizer and immersing in an iodine solution uniaxially (normally 5 to 10 times). It is known that it is manufactured by bonding at least one surface with an adhesive.

  High durability is required for a display device for in-vehicle use, and high durability is also required for a polarizing plate. Particularly, from the viewpoint of improving water resistance, in recent years, PET (polyethylene terephthalate) films, cycloolefin resin films, acrylic resin films, and the like have been used as polarizer protective films as alternatives to conventional TAC films (triacetyl cellulose films). It has come to be.

  As such a technique, Japanese Patent Application Laid-Open No. 2015-166875 discloses that a specific white backlight light source, an oriented polyester film (polyester resin film) having a specific retardation, and a polarizer are used. There is disclosed a liquid crystal display device having a polarizing plate whose axis is substantially parallel to the main axis of orientation of the polyester resin film. According to the document, the polarizing plate realizes high durability and mechanical strength suitable for thinning, and the liquid crystal display device can suppress occurrence of rainbow unevenness. Here, the document discloses that in a polarizing plate, a polyester resin film containing an ultraviolet absorber is used as one polarizer protective film, and that the polyester resin film has a hard coat layer. Further, it discloses that a norbornene-based film (a kind of cycloolefin resin film) or an acrylic film (acrylic resin film) is used as the other polarizer protective film.

  JP-A-2006-107498 discloses a protective film having a base film and a surface protective layer containing a cured product of an ultraviolet absorber having two different molecular weights and an ionizing radiation-curable resin composition. Have been. According to the literature, such a protective film can realize a high ultraviolet ray cut function, a low coloring property, and a sufficient scratch resistance for protecting members such as a polarizer. Here, this document discloses that a protective film using a polyester resin film as a base film is used as one polarizer protective film in a polarizing plate. Further, it discloses that a stretched cyclic olefin film (cycloolefin resin film) as a retardation film (retardation film) is used as the other polarizer protective film.

  However, the polarizing plate disclosed in JP-A-2005-166875 or JP-A-2006-107498 has an ultraviolet cut function and is excellent in water resistance, but cracks of the cycloolefin resin film at the time of cutting the polarizing plate ( There has been a problem that cracks, cracks and nicks at the edges may occur. It is necessary to cut the polarizing plate for deformed panel use along the shape of the panel. At this time, in the polarizing plate disclosed in JP-A-2015-87575 or JP-A-2006-107498, a cycloolefin resin film is used. In particular, it has been a particular problem that cracks (cracks, cracks and swells at the edges) occur more frequently than when cutting a conventional rectangle.

  Moreover, the polarizing plate disclosed in JP-A-2015-166875 or JP-A-2006-107498 has a problem that peeling may easily occur between the polarizer protective film and the polarizer. Was. In a polarizing plate for in-vehicle use, durability under a severe environment, particularly under high temperature is required. However, in a polarizing plate disclosed in JP-A-2005-166875 or JP-A-2006-107498, under a high temperature. There has been a particular problem that peeling occurs between the polarizer protective film and the polarizer due to the use of.

  The present invention has been made in view of the above problems, using a polyester resin film, a cycloolefin resin film or an acrylic resin film as a polarizer protective film, a polarizing plate having an ultraviolet cut function, the polarizing plate It is an object of the present invention to provide means capable of reducing the failure at the time of irregular punching and improving the adhesion between the polarizer protective film and the polarizer after aging at a high temperature.

  The above object of the present invention is solved by the following means.

A hard coat layer, a polyester resin film, a polarizer, and a cycloolefin resin film or an acrylic resin film having a laminated structure laminated in this order,
The hard coat layer, and the cycloolefin resin film or the acrylic resin film contains an ultraviolet absorber,
A polarizing plate, wherein the polyester resin film does not substantially contain an ultraviolet absorber.

It is a mimetic diagram showing an example of an odd-shaped panel to which a polarizing plate concerning one mode of the present invention can be applied. FIG. 2 is a schematic cross-sectional view illustrating a structure of a polarizing plate according to a preferred embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described. In the present specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, operations, physical properties, and the like are measured under conditions of room temperature (20 to 25 ° C.) / Relative humidity of 40 to 50% RH.

  In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. In addition, the dimensional ratios in the drawings are exaggerated for convenience of description, and may be different from the actual ratios.

  Unless otherwise specified herein, (meth) acrylate means acrylate or methacrylate, (meth) acryl means acryl or methacryl, and (meth) acrylonitrile means acrylonitrile or methacrylonitrile.

  Also, unless otherwise defined herein, “copolymerization” means block copolymerization, random copolymerization, graft copolymerization or alternating copolymerization, and “copolymer” means block copolymerization. It means a coalesced, random copolymer, graft copolymer or alternating copolymer.

<Polarizing plate>
The present invention has a laminated structure in which a hard coat layer, a polyester resin film, a polarizer, and a cycloolefin resin film or an acrylic resin film are laminated in this order, the hard coat layer, and the cycloolefin resin film Alternatively, the present invention relates to a polarizing plate, wherein the acrylic resin film contains an ultraviolet absorber, and the polyester resin film contains substantially no ultraviolet absorber. According to the polarizing plate according to the present invention, in the case of using a polyester resin film and a cycloolefin resin film or an acrylic resin film as a polarizer protective film, and a polarizing plate having an ultraviolet cut function, a failure occurs when the polarizing plate is punched out of an irregular shape. And the adhesion between the polarizer protective film and the polarizer after aging at high temperatures can be improved.

  The present inventors presume the mechanism by which the problem is solved by the above configuration as follows.

  The polyester resin film generally has a lower glass transition temperature than a TAC film conventionally used as a polarizer protective film. Thus, when the polyester resin film contains an ultraviolet absorber, as in the case of the polarizing plate according to JP-A-2015-87575, the glass transition temperature is further lowered and the film is softened. The polarizing plate including such a polyester resin film is easily deformed by following the polarizing plate itself when the blade is pressed during cutting. Also, unlike the conventional rectangular punching, in the modified punching, the force required for cutting is not constant in each direction. At this time, in the polarizing plate including such a polyester resin film, due to the easiness of deformation of the polarizing plate and the force required for cutting in each direction in the irregular punching, the in-plane of the polarizing plate at the time of the irregular punching. In some cases, failures such as poor cutting, cracking of the polarizer protective film, or separation of the polarizer protective film from the polarizer may occur. In addition, due to the low glass transition temperature of the polyester resin film, and the softening, the polyester resin film curls over time at high temperatures, and the curl causes peeling between the polarizer protective film and the polarizer. Will occur.

  In addition, in the polarizing plate according to JP-A-2005-166875 or JP-A-2006-107498, since the polarizer protective films made of different materials are arranged on both surfaces of the polarizer, the curl balance of the entire polarizing plate is maintained. It becomes difficult. Further, in the polarizing plate according to JP-A-2006-107498, it is necessary to add an ultraviolet absorber to the surface protective layer in order to realize an ultraviolet cut function. It is more difficult to maintain the curl balance of As a result, in the polarizing plate according to JP-A-2015-166875 or JP-A-2006-107498, fine curls are generated in different states depending on locations in the plane of the polarizing plate. In such a polarizing plate, due to the occurrence of fine curl and the force required for cutting in each direction in the irregular punching, a part of the polarizing plate surface during the irregular punching, a polarizer protective film, especially Cracks of the cycloolefin resin film and the acrylic resin film will occur.

  On the other hand, the polyester resin film used for the polarizing plate according to the present invention does not substantially contain an ultraviolet absorber, so that the glass transition temperature is not lowered and the film is not softened. Therefore, in the polarizing plate according to the present invention, the deformation of the film at the time of punching out a deformed shape is suppressed, and the failure at the time of punching out a deformed shape is reduced. In the polarizing plate according to the present invention, the occurrence of curling of the polyester resin film due to aging at high temperatures is suppressed, and the adhesion between the polarizer protective film and the polarizer after aging at high temperatures is improved.

  In addition, the polarizer protective film having no hard coat layer is usually arranged on the side closer to the panel among the two polarizer protective films. Conventionally, a cycloolefin resin film or an acrylic resin film, which is disposed relatively closer to the panel, has special properties to satisfy optical characteristics (particularly, retardation, etc.) required as a polarizer protective film or retardation film. It was common that various additives were added and resin modification was performed. Thus, in the art, the addition of an ultraviolet absorber to a cycloolefin resin film or an acrylic resin film that is disposed relatively closer to the panel may cause a decrease in the optical characteristics and productivity. Has not been actively considered.

  On the other hand, in the polarizing plate according to the present invention, the UV absorber is added to the hard coat layer to realize the UV cut function, and the cycloolefin resin film is disposed as a film relatively closer to the panel. Alternatively, an ultraviolet absorber is also added to the acrylic resin film. As a result, the polarizing plate according to the present invention can maintain the curl balance of the entire polarizing plate, and suppresses the occurrence of minute curls in different positions in the plane of the polarizing plate. Therefore, in the polarizing plate according to the present invention, cracks generated in the polarizer protective film, particularly the cycloolefin resin film or the acrylic resin film, are reduced in a part of the plane of the polarizing plate at the time of blank punching.

  Furthermore, in the polarizing plate according to the present invention, when the cycloolefin resin film or the acrylic resin film contains an ultraviolet absorber, the interaction between these films and the polarizer increases. Therefore, the polarizing plate according to the present invention, even when the deformation of the polarizer protective film occurs over time under high temperature, peeling between these films and the polarizer will be suppressed, these films And the polarizer are improved in adhesion.

  The above mechanism is based on a guess, and its correctness does not affect the technical scope of the present invention.

  FIG. 2 is a schematic cross-sectional view showing the structure of a polarizing plate according to a preferred embodiment of the present invention. The polarizing plate 1 has a hard coat layer 2, a polyester resin film 3, a polarizer 5, and a cycloolefin resin film 6 in this order. Here, the hard coat layer 2 and the cycloolefin resin film 6 contain an ultraviolet absorber. Further, the polyester resin film 3 does not substantially contain an ultraviolet absorber. Here, the easy adhesion layer 4 is a functional layer which may be arbitrarily provided. Further, in the present invention, an acrylic resin film containing an ultraviolet absorber can be adopted instead of the cycloolefin resin film 6. In the polarizing plate 1, the adhesive layer used for bonding the polarizer 5 to the easy-adhesion layer 4 and the cycloolefin resin film 6 of the polyester resin film 3 is not shown.

  Hereinafter, each component of the polarizing plate according to the present invention will be described in detail.

(Polyester resin film)
A polarizing plate according to one embodiment of the present invention has a polyester resin film that does not substantially contain an ultraviolet absorber.

  The polyester resin film refers to a film containing polyester in an amount of 50% by mass or more based on the total mass of the film. If the content of the polyester is less than 50% by mass, excellent water resistance derived from the polyester may not be obtained. From the same viewpoint, the content of the polyester is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and more preferably 99% by mass or more. Is particularly preferred (the upper limit is 100% by mass).

  In this specification, the “polyester resin film” refers to a film itself that can be formed from polyester alone or a composition containing the same, and does not include other functional layers such as a hard coat layer.

[polyester]
Polyester (polyester resin) which is a raw material resin of the polyester resin film can be obtained by polycondensing an arbitrary dicarboxylic acid component and an arbitrary diol component. The dicarboxylic acid component is not particularly limited. For example, terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5- Naphthalenedicarboxylic acid, diphenylcarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracenedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydro Terephthalic acid, hexahydroisophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, Pimelic acid Azelaic acid, dimer acid, sebacic acid, and suberic acid, dodecamethylene dicarboxylic acid, and the like salts and anhydrides thereof. Among these, terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, or salts thereof or These anhydrides are preferable, and terephthalic acid or a salt thereof or an anhydride thereof is more preferable.

  The diol component is not particularly limited. For example, ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexane dimethanol, 1,4-cyclohexane dimethanol, decamethylene glycol, 1,3- Examples thereof include propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis (4-hydroxyphenyl) propane, and bis (4-hydroxyphenyl) sulfone. it can. Among these, ethylene glycol and propylene glycol are preferable, and ethylene glycol is more preferable.

  As the dicarboxylic acid component and the diol component constituting the polyester, these may be used alone or in a combination of two or more.

  Specific polyester resins constituting the polyester resin film include, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene terephthalate, polybutylene terephthalate, etc., preferably, polyethylene terephthalate (PET), or Polyethylene naphthalate (PEN), more preferably polyethylene terephthalate (PET). The polyester resin may contain another copolymer component as needed. From the viewpoint of mechanical strength, the proportion of the copolymer component is 3 mol% with the total of the dicarboxylic acid component and the diol component being 100 mol%. Is preferably not more than 2 mol%, more preferably not more than 1.5 mol% (lower limit is 0 mol%). These resins are excellent not only in transparency but also in thermal and mechanical properties. The retardation of these resins can be easily controlled by stretching.

  The polyester can be synthesized by a general production method.

[UV absorber]
It is preferable that the polyester resin film does not substantially contain an ultraviolet absorber. In the present specification, "substantially does not contain an ultraviolet absorber" means that the content of the ultraviolet absorber is 0.1% by mass or less based on the total mass of the polyester resin film. Here, the “polyester resin film” refers to a film that can be formed from a resin composition containing polyester, and does not include other functional layers such as a hard coat layer. If the content of the ultraviolet absorbent in the polyester resin film is more than 0.1% by mass based on the total mass of the polyester resin film, the frequency of failures when the polarizing plate is punched out of an irregular shape increases, and the aging at high temperatures There is a possibility that the adhesiveness between the polarizer protective film and the polarizer later becomes insufficient. From such a viewpoint, the content of the ultraviolet absorber in the polyester resin film is more preferably 0.05% by mass or less, and preferably 0.01% by mass or less based on the total mass of the polyester resin film. Is still more preferable, and it is particularly preferable that it is not contained at all (0 mass%).

  In addition, as an ultraviolet absorber which can be contained in a trace amount in the polyester resin film, for example, an ultraviolet absorber contained in a hard coat layer, a cycloolefin resin film, and an acrylic resin film described later can be mentioned.

[optical properties]
The retardations Ro and Rth of the polyester resin film are respectively defined by the following formulas:
Formula (I) Ro = (nx−ny) × d
Formula (II) Rth = {(nx + ny) / 2−nz} × d
(However, nx represents the refractive index in the direction x where the refractive index becomes maximum in the in-plane direction of the film, ny represents the refractive index in the direction y orthogonal to the direction x in the in-plane direction of the film, nz represents the refractive index in the thickness direction z of the film, and d (nm) represents the thickness of the film).

  The upper limit of the in-plane retardation Ro (590) of the polyester resin film in an environment of 23 ° C. and 55% RH with respect to light having a wavelength of 590 nm is not particularly limited, but is preferably as small as possible and 1000 nm or less. preferable. When the retardation Ro (590) in the in-plane direction is within this range, a light source having a sharper RGB intensity distribution than a white light source (blue LED + yellow phosphor) is used as the backlight of the liquid crystal display device. Furthermore, since the interference of light itself due to retardation is reduced, it is possible to further reduce rainbow unevenness. From the same viewpoint, the in-plane retardation Ro (590) of the polyester resin film is more preferably equal to or less than 800 nm, further preferably equal to or less than 350 nm, and particularly preferably equal to or less than 300 nm. The in-plane retardation Ro (590) of the polyester resin film is most preferably 0 nm from the above viewpoint, but from the viewpoint of productivity, the in-plane retardation Ro (590) of the polyester resin film is preferred. The lower limit of () is preferably 30 nm or more. The in-plane retardation Ro (590) can be controlled by the type of polyester, stretching conditions described later, and the like.

  The in-plane retardation Ro (590) of the polyester resin film in the in-plane direction with respect to light having a wavelength of 590 nm under an environment of 23 ° C. and 55% RH was measured using an automatic birefringence meter Axo Scan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). ) Can be measured.

[Thickness]
Further, the lower limit of the thickness of the polyester resin film is preferably 5 μm or more, more preferably 10 μm or more, further preferably 15 μm or more, and particularly preferably 20 μm or more. Within this range, better water resistance and mechanical strength can be obtained. Further, the upper limit of the thickness of the polyester resin film is preferably 300 μm or less, more preferably 200 μm or less, further preferably 100 μm or less, and particularly preferably 40 μm or less. Within this range, it is possible to achieve both further thinning and better visibility.

  The ratio of the thickness (μm) of the polyester resin film to the thickness (μm) of the cycloolefin resin film or acrylic resin film described later (thickness (μm) of polyester resin film / thickness (μm) of cycloolefin resin film or acrylic resin film) ) Is preferably from 0.1 to 5, more preferably from 0.4 to 4, and even more preferably from 1 to 3. Within this range, cracks generated in the polarizer protective film, particularly the cycloolefin resin film or the acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the polarizer is further improved. The reason for this is that, in the above range, the curl balance of the entire polarizing plate becomes good, and the curling of the polyester resin film due to the aging at a high temperature and the fine curling that occurs in different states depending on the location in the plane of the polarizing plate. It is speculated that this is because it is suppressed. The above mechanism is based on a guess, and its correctness does not affect the technical scope of the present invention.

(Method for producing polyester resin film)
The polyester resin film can be obtained according to a general manufacturing method. Specifically, a non-oriented polyester extruded into a sheet shape by melting a polyester resin is stretched in the machine direction (MD direction) using a speed difference between rolls at a temperature equal to or higher than the glass transition temperature, or a tenter is used. Stretching in the transverse direction (TD direction) used, or stretching in both directions, and further performing a heat treatment and a relaxation treatment (relaxation treatment) as necessary to produce a polyester resin film by melt casting. And the like. The details of the melt casting method will be described later. The polyester resin film may be a uniaxially stretched film (uniaxially oriented film) or a biaxially stretched film (biaxially oriented film), but is preferably a uniaxially stretched film.

  Production conditions for obtaining the polyester resin film can be appropriately set according to a known method. For example, the melting temperature is preferably from 200 to 300 ° C, and more preferably from 250 to 300 ° C. The longitudinal stretching temperature and the transverse stretching temperature are preferably from 80 to 130 ° C, more preferably from 90 to 125 ° C. The longitudinal stretching ratio is preferably from 1 to 3.5 times, and more preferably from 1 to 3 times. Further, the transverse stretching ratio is preferably 1 to 3 times, more preferably 1 to 2.5 times.

  Controlling the retardation to a specific range can be performed by appropriately setting a stretching ratio, a stretching temperature, and a film thickness. For example, as the difference in the stretching ratio between the longitudinal stretching and the transverse stretching is larger, the stretching temperature is lower, and the thickness of the film is larger, a higher retardation is easily obtained. Conversely, as the difference in stretching ratio between longitudinal stretching and transverse stretching is smaller, the stretching temperature is higher, and the thickness of the film is smaller, lower retardation is more likely to be obtained. Further, as the stretching temperature is higher and the total stretching ratio is smaller, a film having a lower ratio (Ro / Rt) between the retardation value and the retardation value in the thickness direction can be easily obtained. Conversely, as the stretching temperature is lower and the total stretching ratio is higher, it is easier to obtain a film having a higher ratio (Ro / Rt) of the retardation value to the thickness direction retardation value.

  The heat treatment temperature is preferably in the range of 140 to 240 ° C, and more preferably in the range of 170 to 240 ° C.

  Usually, the temperature of the relaxation treatment (relaxation treatment) is preferably in the range of 100 to 230 ° C, more preferably in the range of 110 to 210 ° C, and still more preferably in the range of 120 to 180 ° C. Further, the relaxation amount (relaxation amount) is usually preferably in the range of 0.1 to 20%, more preferably in the range of 1 to 10%, and more preferably in the range of 2 to 5%. Is more preferable. The temperature and the amount of relaxation of the relaxation treatment are not particularly limited, but are preferably set so that the heat shrinkage at 150 ° C. of the polyester film after the relaxation treatment is 2% or less.

  In the uniaxial stretching and the biaxial stretching, after the transverse stretching, heat treatment or stretching can be performed again in order to alleviate distortion of the main alignment axis typified by bowing. .

[Other functional layers]
The polarizing plate according to one embodiment of the present invention has a hard coat layer described later as a functional layer on the surface of the polyester resin film opposite to at least the surface on the side where the polarizer is present, but in addition to the hard coat layer It may further have another functional layer. In addition, each functional layer may be provided directly on the surface of the polyester resin film, or may be provided on the polyester resin film via another functional layer. As the other functional layer, a layer generally provided in a polarizing plate or a polarizer protective film can be appropriately selected. As other functional layers, for example, an easy-adhesion layer, an antiglare layer, an antireflection layer, a low reflection layer, a low reflection antiglare layer, an antireflection antiglare layer, an antistatic layer, a silicone layer, an adhesive layer, and an antifouling layer , A fingerprint-resistant layer, a water-repellent layer, a blue-cut layer, and the like.

  In the polarizing plate according to one embodiment of the present invention, when providing a hard coat layer or another functional layer on at least one surface side of the polyester resin film, it is preferable to provide an easy adhesion layer on the surface of the polyester resin film. At that time, from the viewpoint of suppressing interference due to reflected light, it is preferable to adjust the refractive index of the easy-adhesion layer so as to be close to the geometric mean of the refractive index of the functional layer and the refractive index of the oriented film. A known method can be used to adjust the refractive index of the easy-adhesion layer. For example, the refractive index can be easily adjusted by adding silica, titanium, zirconium, or other metal species to the binder resin. The coating liquid used for forming the easily adhesive layer is preferably an aqueous coating liquid containing at least one of a water-soluble or water-dispersible copolymerized polyester resin, an acrylic resin and a polyurethane resin. Examples of these coating solutions include, for example, Japanese Patent Publication No. 6-81714, Japanese Patent No. 3200929, Japanese Patent No. 3632044, Japanese Patent No. 4547644, Japanese Patent No. 4770971, Japanese Patent No. 3567927, and Japanese Patent No. 3589232. And water-soluble or water-dispersible copolymerized polyester resin solutions, acrylic resin solutions, polyurethane resin solutions, and the like, which are disclosed in Japanese Patent Application Laid-Open No. 3589233, Japanese Patent No. 3900191, and Japanese Patent No. 4150982. Among these, a water-soluble or water-dispersible copolymerized polyester resin is preferable.

  Further, when the polyester resin film has an easy-adhesion layer on its surface, the polyester resin film having the easy-adhesion layer is obtained by applying a coating liquid used for forming the easy-adhesion layer on the surface of the unstretched polyester resin film, and drying. It is preferable to form an easy-adhesion layer by the following method. Then, in the polyester resin film having the easy-adhesion layer, the unstretched polyester resin film is subjected to the above-described longitudinal stretching and / or transverse stretching, or both of the above-mentioned stretching, and heat treatment and relaxation treatment (relaxation) as necessary. It is more preferable to further carry out (treatment).

  Although the lower limit of the thickness of the easy-adhesion layer is not particularly limited, it is preferably 0.01 μm or more, and more preferably 0.1 μm or more, from the viewpoint of developing the function of the easy-adhesion layer. The upper limit of the thickness of the easy-adhesion layer is not particularly limited, but is preferably 5 μm or less, more preferably 1 μm or less, from the viewpoint of thinning.

(Hard coat layer)
A polarizing plate according to one embodiment of the present invention has a hard coat layer containing an ultraviolet absorber. The hard coat layer has an effect of improving the scratch resistance of the polarizing plate.

  The hard coat layer is preferably a cured product of an ionizing radiation-curable resin composition containing a resin component containing an ionizing radiation-curable compound and an ultraviolet absorber. That is, the ionizing radiation-curable resin composition preferably contains at least a resin component containing an ionizing radiation-curable compound and an ultraviolet absorber. The ionizing radiation-curable resin composition may contain a resin component such as a thermoplastic resin other than the ionizing radiation-curable compound.

  The ionizing radiation-curable resin composition is a resin composition that cures when irradiated with ionizing radiation. As the ionizing radiation, among electromagnetic waves or charged particle beams, those having an energy quantum capable of polymerizing or cross-linking molecules, for example, ultraviolet (UV) or electron beam (EB) are used, and in addition, X-rays, γ-rays Charged particle beams such as electromagnetic waves, α rays, and ion beams are also used.

[Ionizing radiation-curable compound]
The ionizing radiation-curable compound contained in the ionizing radiation-curable resin composition is not particularly limited, and may be appropriately selected from known polymerizable monomers, polymerizable oligomers, and prepolymers.

  As the polymerizable monomer, a (meth) acrylate monomer having a radically polymerizable unsaturated group in a molecule is preferable, and among them, a polyfunctional (meth) acrylate monomer is preferable. The polyfunctional (meth) acrylate monomer is not particularly limited as long as it is a (meth) acrylate monomer having two or more ethylenically unsaturated bonds in a molecule. For example, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate ) Acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Are preferred. Further, the (meth) acrylate may be one in which a part of the molecular skeleton is modified, and is modified by ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, or the like. Can also be used. One of these (meth) acrylate monomers may be used alone, or two or more thereof may be used in combination.

  The number of functional groups of the polyfunctional (meth) acrylate monomer is not particularly limited as long as it is 2 or more. From the viewpoint of improving the curability of the ionizing radiation-curable resin composition and the scratch resistance of the surface protective layer, 2 to 8 are preferable. It is preferably from 2 to 6, more preferably from 3 to 6.

  From the viewpoint of improving the scratch resistance of the surface protective layer, the molecular weight of the polyfunctional (meth) acrylate monomer is preferably less than 1,000, more preferably 200 to 800.

  As the polymerizable oligomer, a polyfunctional (meth) acrylate oligomer having two or more radically polymerizable unsaturated groups in the molecule is preferably used. The (meth) acrylate-based oligomer is not particularly limited. For example, urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, polyfluoroalkyl (meth) acrylate, silicone (Meth) acrylate and the like. Further, the (meth) acrylate may be one in which a part of the molecular skeleton is modified, and is modified by ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, or the like. Can also be used. These may be used alone or in combination of two or more.

  The number of functional groups of the polyfunctional (meth) acrylate oligomer is not particularly limited as long as it is 2 or more. From the viewpoint of improving the curability of the ionizing radiation-curable resin composition and the abrasion resistance of the surface protective layer, 2 to 8 are preferable. Preferably, it is 2-6 more preferably.

  The weight average molecular weight of the polyfunctional (meth) acrylate oligomer is preferably from 1,000 to 20,000, more preferably from 1,000 to 15,000, and from 1,000 to 10,000. More preferably, it is particularly preferably from 1,000 to 5,000. The weight average molecular weight is a value determined by gel permeation chromatography (GPC) in terms of polystyrene.

  The content of the ionizing radiation-curable compound is preferably 50 to 99.7% by mass, more preferably 60 to 98% by mass, and still more preferably 70 to 93% by mass, based on the total mass of the ionizing radiation-curable resin composition. And particularly preferably 80 to 90% by mass. The content of the cured product of the ionizing radiation-curable compound in the cured product of the ionizing radiation-curable resin composition is substantially the same as the content of the ionizing radiation-curable compound in the ionized radiation-curable resin composition. is there.

  The ionizing radiation-curable compound is preferably a polymerizable oligomer, more preferably urethane (meth) acrylate, and further preferably urethane acrylate.

  Commercial products may be used as the ionizing radiation-curable compound. Examples of commercially available products include UV-7600B manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

  When the ionizing radiation-curable compound is an ultraviolet-curable compound, the ionizing radiation-curable resin composition preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator.

  The photopolymerization initiator is not particularly limited, and includes, for example, acetophenone, α-hydroxyalkylphenone, acylphosphine oxide, benzophenone, Michler's ketone, benzoin, benzylmethylketal, benzoylbenzoate, α-acyloxime ester, thioxanthones, and the like. Can be These can be used alone or in combination of two or more.

  Among these, the photopolymerization initiator is preferably an acylphosphine oxide, and is preferably 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide or bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. And more preferably 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

  Commercial products may be used as the ionizing radiation-curable compound. Examples of commercially available products include IRGACURE (registered trademark) TPO and IRGACURE (registered trademark) 819 manufactured by Ciba Specialty Chemicals Co., Ltd.

  The content of the photopolymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 1 to 15 parts by mass, still more preferably 1 to 10 parts by mass, particularly preferably 100 parts by mass of the ionizing radiation-curable compound. Is 1 to 5 parts by mass. The content of the ionizing radiation-curable compound in the cured product of the ionizing radiation-curable resin composition is substantially the same as the content of the ionized radiation-curable compound in the cured product.

  In addition, the photopolymerization accelerator has an effect of reducing polymerization obstacles caused by air during curing and increasing the curing speed. The photopolymerization accelerator is not particularly limited, and examples thereof include isoamyl p-dimethylaminobenzoate and ethyl p-dimethylaminobenzoate. These can be used alone or in combination of two or more.

[UV absorber]
The ionizing radiation-curable resin composition contains an ultraviolet absorber. The ultraviolet absorber has an action of giving an ultraviolet ray cutting ability by absorbing ultraviolet rays. The ultraviolet absorber is not particularly limited, and an ultraviolet absorber known in the field of a hard coat layer, a polarizer protective film, or a polarizing plate can be appropriately used.

  The ultraviolet absorber is not particularly limited, and examples thereof include a benzophenone-based compound, a benzotriazole-based compound, a triazine-based compound, a benzoxazine-based compound, a salicylate-based compound, and a cyanoacrylate-based compound.

  Among these, from the viewpoint of ultraviolet absorption, a benzophenone-based compound, a benzotriazole-based compound or a triazine-based compound is preferable, a benzotriazole-based compound or a triazine-based compound is more preferable, and a benzotriazole-based compound is used. Is more preferable.

  The benzophenone-based compound is not particularly limited, and examples thereof include 2,2-dihydroxy-4,4-dimethoxybenzophenone.

  The benzotriazole-based compound is not particularly limited, but is preferably a compound represented by the following general formula (1), and more preferably a compound represented by the following general formula (2).

In the formula, G ¹ and G ² each independently represent a hydrogen atom, a cyano group, a chlorine atom, a fluorine atom, a —CF ₃ group, a —CO—G ³ group, an E ³ SO— group, or an E ³ SO ₂ — Represents a group.

G ³ is a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkenyl group having 2 to 18 carbon atoms, or a cycloalkyl group having 5 to 12 carbon atoms. Or an arylalkyl group having 7 to 15 carbon atoms, an aryl group, or the phenyl group or the phenylalkyl group in which a phenyl ring is substituted by 1 to 4 alkyl groups having 1 to 4 carbon atoms.

E ¹ and E ² each independently represent a linear or branched alkyl group having 1 to 24 carbon atoms; a linear or branched alkenyl group having 2 to 18 carbon atoms; An arylalkyl group having 7 to 15 carbon atoms; an aryl group; an alkyl group having 1 to 4 carbon atoms, the aryl group or the arylalkyl substituted with 1 to 4 carbon atoms. Groups; one or more of -OH groups, -OCOE ¹¹ groups, -OE ⁴ groups, -NCO groups, -NH ₂ groups, -NHCOE ¹¹ groups, -NHE ⁴ groups, -N (E ⁴ ) ₂ An alkyl group having 1 to 24 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, which is substituted by a group, -COOH group or -COOE ⁵ group; one or more -O- groups, -NH- group or- E ⁴ - is interrupted by groups, and unsubstituted or one or more than that,, -OH group, -OE ⁴ group, -NH ₂ group, may be substituted by -COOH group or -COOE ⁵ group, wherein Represents an alkyl group or the aforementioned alkenyl group. Here, -O- group, -NH- group or -NE 4 ^- position of the interruption due group is not particularly limited, the alkyl group is preferably an alkyl group of the alkenyl group or E ^5,.

E ⁴ represents a linear or branched alkyl group having 1 to 24 carbon atoms.

E ⁵ is straight-chain or branched-chain having 1 to 24 carbon atoms which may be unsubstituted or substituted by one or more —OH, COOH or —NH ₂ groups. Represents an alkyl group.

E ¹¹ represents a hydrogen atom, a linear or branched alkylene group having 1 to 18 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, from 2 to 18 carbon atoms linear or branched An alkenyl group, an aryl group having 6 to 14 carbon atoms, or an arylalkyl group having 7 to 15 carbon atoms.

E ³ is a linear or branched alkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 2 to 20 carbon atoms, an alkenyl group having 3 to 18 carbon atoms, and a alkenyl group having 5 to 12 carbon atoms. A cycloalkyl group, an arylalkyl group having 7 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkyl group having 1 to 4 carbon atoms, the aryl group substituted by one or two, Or a 1,1,2,2-tetrahydroperfluoroalkyl group (the perfluoroalkyl portion of this group consists of 6 to 16 carbon atoms).

  Hereinafter, specific examples of the benzotriazole-based compound are shown in the following exemplary compounds 1 to 6, but are not limited thereto.

Further, the benzotriazole compound may be a multimer containing the compound of the general formula (1) or the general formula (2) as a partial structure. The multimers, for example, compound the E ¹ or the E ² is a linking group. The compound wherein E ¹ or E ² is a linking group includes one or more hydrogen atoms from E ¹ or E ² in the compound of the above general formula (1) or the above general formula (2). And a structure in which the compound of the general formula (1) or the general formula (2) is linked at this portion. Examples of the multimer include a —COOH group derived from the compound of the above general formula (1) or (2) and a —OH group derived from a diol (eg, ethylene glycol, propylene glycol, etc.). May be a compound having a structure linked by forming an ester bond between the two.

  The multimer is preferably a dimer, and includes, for example, a structure as exemplified compound A below.

  Examples of the benzotriazole-based compound include methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate and methyl 3- (3- (2H-benzotriazole-2). -Yl) -5-tert-butyl-4-hydroxyphenyl) propionate and the reaction product of polyethylene glycol (methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4- (Hydroxyphenyl) propionate adduct of polyethylene glycol or dimer of methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate via polyethylene glycol (For example, the above-mentioned exemplified compound A), Or a mixture containing these), 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4-1,1,3,3-tetramethylbutyl) phenol ( The above exemplified compound 1) and 2- (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) benzotriazole (the above exemplified compound 6) are particularly preferred.

  The triazine-based compound is not particularly limited, but is preferably a compound represented by the following general formula (3).

In the formula, R ¹ is a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an alkenyl group having 3 to 8 carbon atoms, Represents an aryl group, an alkylaryl group having 7 to 18 carbon atoms, an alkenylaryl group having 7 to 18 carbon atoms, or an arylalkyl group having 7 to 18 carbon atoms. However, these alkyl groups, cycloalkyl groups, alkenyl groups, aryl groups, alkylaryl groups or arylalkyl groups are hydroxy groups, halogen atoms, alkyl groups having 1 to 12 carbon atoms or alkoxy groups having 1 to 12 carbon atoms. And it may be interrupted by an oxygen atom, a sulfur atom, a carbonyl group, an ester group, an amide group or an imino group. Also, the above substitutions and interruptions may be combined.

R ² each independently represent a hydrogen atom, an alkyl group or an alkenyl group having 3 to 8 carbon atoms of 1 to 8 carbon atoms.

At least one of R ³ is a hydroxy group, and when not a hydroxy group, represents a hydrogen atom.

R ⁴ each independently represents a hydrogen atom or O—R ¹ .

Examples of the linear or branched alkyl group having 1 to 12 carbon atoms represented by R ¹ in the general formula (3) include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl. Examples thereof include linear or branched alkyl groups such as butyl, amyl, isoamyl, tert-amyl, hexyl, heptyl, n-octyl, isooctyl, tert-octyl, 2-ethylhexyl, nonyl, isononyl, decyl, undecyl and dodecyl.

Examples of the cycloalkyl group having 3 to 8 carbon atoms represented by R ¹ in the general formula (3) include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl and the like.

Examples of the aryl group having 6 to 18 carbon atoms, the alkylaryl group having 7 to 18 carbon atoms or the alkenylaryl group having 7 to 18 carbon atoms represented by R ¹ in the general formula (3) include, for example, phenyl, naphthyl , 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-vinylphenyl, 3-isopropylphenyl, 4-isopropylphenyl, 4-butylphenyl, 4-isobutylphenyl, 4-tert-butylphenyl, 4- Hexylphenyl, 4-cyclohexylphenyl, 4-octylphenyl, 4- (2-ethylhexyl) phenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl, 2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl, 3,5-dimethylphenyl, 2,4-di-te rt-butylphenyl, 2,5-di-tert-butylphenyl, 2,6-di-tert-butylphenyl, 2,4-ditert-pentylphenyl, 2,5-ditert-amylphenyl, 2,5- Ditert-octylphenyl, biphenyl, 2,4,5-trimethylphenyl, and the like, and examples of the arylalkyl group having 7 to 18 carbon atoms include benzyl, phenethyl, 2-phenylpropan-2-yl, and diphenylmethyl And the like.

In the general formula (3), examples of the alkenyl group having 3 to 8 carbon atoms represented by R ¹ and R ² include linear and branched propenyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl are unsaturated. This can be mentioned regardless of the position of the bond.

In the general formula (3), examples of the alkyl group having 1 to 8 carbon atoms represented by R ² include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, amyl, Examples include tert-amyl, octyl, and tert-octyl. Of these, a methyl group is preferable because of its excellent ultraviolet absorbing ability.

  Specific examples of the triazine-based compound represented by the general formula (3) are shown in the following exemplified compounds 7 to 18, but are not limited thereto.

  The triazine-based compound is preferably a hydroxyphenyltriazine (HPT) -based compound, and particularly preferably the exemplified compound 17 or the exemplified compound 18.

  Further, as the ultraviolet absorber, a polymer type ultraviolet absorber may be used. Examples of the high-molecular ultraviolet absorber include (co) polymers having an ultraviolet-absorbing group. For example, a homopolymer of an ultraviolet-absorbing monomer, an ultraviolet-absorbing monomer, and another monomer Preferred is a copolymer with a polymer. The UV-absorbing monomer is preferably an ethylenically unsaturated monomer. For example, a benzotriazole skeleton, a benzophenone skeleton, a triazine skeleton, a benzoxazine skeleton, or the like in an ester substituent of a (meth) acrylate ester. And the like. Further, the other monomer may be any monomer that can be copolymerized with the ultraviolet absorbing monomer, for example, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, Alkyl (meth) acrylates such as propyl (meth) acrylate and butyl (meth) acrylate, and hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate No. These can be used alone or in combination of two or more. These can be used alone or in combination of two or more.

  Among them, (meth) acrylic acid or methyl (meth) acrylate is preferable, methacrylic acid or methyl methacrylate is more preferable, and methyl methacrylate is more preferable.

  As the high-molecular ultraviolet absorber, a high-molecular ultraviolet absorber having a benzophenone group, a triazine group, or a benzotriazole group (a benzophenone-based compound, a triazine-based compound, or a benzotriazole-based compound, which is a polymer compound) is preferably used. It is more preferable that the polymer ultraviolet absorber has a triazine group or a benzotriazole group, and it is further preferable that the polymer ultraviolet absorber has a benzotriazole group. The polymer type ultraviolet absorber having a benzotriazole group is not particularly limited, and includes, for example, a polymer type ultraviolet absorber represented by the following general formula (4).

(In the general formula (4), R ^{10 to} R ¹² each independently represent a hydrogen atom or a methyl group. R ¹³ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a benzyl group, or an aryl group. R ¹⁴ and R ¹⁵ each independently represent an alkylene group having 1 to 3 carbon atoms, a, b and c each represent a molar ratio of each structural unit represented by the general formula (4), and a + b + c = 1 A and b each represent a number greater than or equal to 0, and c represents a number other than 0.)
In addition, from the viewpoint of ultraviolet absorbing ability, in the general formula (4), c is preferably 0.3 or more, more preferably 0.5 or more, and a preferable upper limit is 0.8 or less.

Further, R ^{10 to} R ¹³ are preferably a methyl group. Further, R ¹⁴ or R ¹⁵ is preferably a methylene group or an ethylene group, and more preferably an ethylene group. b is preferably b = 0.

  The weight-average molecular weight of the high-molecular-weight ultraviolet absorber is 1,000 or more, and from the viewpoint of ultraviolet-absorbing ability and solubility in the resin composition, the weight-average molecular weight is preferably 150,000 or less, and 3,000 to 100,000. Is more preferable, 5,000 to 80,000 is further preferable, and 10,000 to 80,000 is particularly preferable. The weight average molecular weight of the high molecular weight ultraviolet absorber is a value determined by polystyrene conversion by GPC.

  Commercial products may be used as the ultraviolet absorber. Commercially available products are not particularly limited. For example, benzotriazole-based compounds include Tinuvin (registered trademark) 1130 and Tinuvin (registered trademark) 928 manufactured by BASF Japan Co., Ltd., and JF-80 manufactured by Johoku Chemical Co., Ltd. However, as a triazine-based compound, Tinuvin (registered trademark) 477 manufactured by BASF Japan Co., Ltd., and as a benzophenone-based compound, Uvinul (registered trademark) 3049 manufactured by BASF, etc., and as a polymer type ultraviolet absorber, And UVA-5080 manufactured by Shin-Nakamura Kogyo Co., Ltd., and UVA1935LH manufactured by BASF, respectively.

  As the ultraviolet absorber contained in the hard coat layer, from the viewpoint of reducing the failure at the time of punching out the irregular shape of the polarizing plate and improving the adhesion between the polarizer protective film and the polarizer after aging at a high temperature, benzoic acid Particularly preferred are triazole-based compounds. Among these, a compound having two or more benzotriazole skeletons in the molecule, such as a benzotriazole-based compound that is a multimer (for example, a dimer) or a high-molecular-weight ultraviolet absorber having a benzotriazole group, may be used. Very preferred.

  The lower limit of the molecular weight of the ultraviolet absorber contained in the hard coat layer is reduced from the viewpoint of reducing the failure at the time of punching out the irregular shape of the polarizing plate and improving the adhesion between the polarizer protective film and the polarizer after aging at a high temperature. Therefore, it is preferably 300 or more. From the viewpoint of further improving the adhesiveness between the polarizer protective film and the polarizer after aging at a high temperature, the molecular weight of the ultraviolet absorber is more preferably 700 or more, and still more preferably 900 or more, It is particularly preferred that it is 1,000 or more. In addition, the preferable upper limit of the molecular weight of the ultraviolet absorber contained in the hard coat layer is the same as the upper limit of the weight average molecular weight of the polymer type ultraviolet absorber. The molecular weight of the ultraviolet absorber is a value calculated from the sum of the atomic weights of the ultraviolet absorbers other than the polymer ultraviolet absorber, and the molecular weight of the polymer absorber is determined by gel permeation chromatography (GPC). Weight-average molecular weight determined in terms of polystyrene as described above.

  The ultraviolet absorber contained in the hard coat layer can be used alone or in combination of two or more.

  The lower limit of the content of the ultraviolet absorber contained in the hard coat layer is preferably at least 0.1 part by mass, more preferably at least 0.5 part by mass, based on 100 parts by mass of the ionizing radiation-curable compound. Preferably, it is 0.8 parts by mass or more, more preferably 1 part by mass or more. Within this range, the ability to cut ultraviolet rays is further improved, and cracks generated in a polarizer protective film, particularly a cycloolefin resin film or an acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular-shaped punching. Further, the upper limit of the content of the ultraviolet absorber contained in the hard coat layer is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, relative to 100 parts by mass of the ionizing radiation-curable compound. It is more preferably at most 3 parts by mass, particularly preferably at most 2 parts by mass. Within this range, cracks generated in the polarizer protective film, particularly the cycloolefin resin film or the acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular punching. The content of the ionizing radiation-curable compound in the cured product of the ionizing radiation-curable resin composition is substantially the same as the content of the ionized radiation-curable compound in the cured product.

  When the hard coat layer contains an ionizing radiation curable compound, the ratio of the content of the ultraviolet absorber contained in the hard coat layer to the content of the ultraviolet absorber contained in the cycloolefin resin film or the acrylic resin film described below. (In the present specification, the content of the ultraviolet absorber with respect to 100 parts by mass of the cycloolefin polymer or the (meth) acrylic polymer contained in the cycloolefin resin film or the acrylic resin film, and contained in the hard coat layer, The ratio of the content (parts by mass) of the ultraviolet absorbent to 100 parts by mass of the ionizing radiation-curable compound, that is, the content (parts by mass) of the ultraviolet absorbent to 100 parts by mass of the ionizing radiation-curable compound contained in the hard coat layer / Cycloolefin resin film or acrylic resin film The UV absorber content (parts by mass) relative to 100 parts by mass of the cycloolefin polymer or the (meth) acrylic polymer contained in the rubber is preferably 0.05 to 1, and 0.1 to 0.1. 7, more preferably 0.1 to 0.5, and particularly preferably 0.1 to 0.3. Within this range, cracks generated in the polarizer protective film, particularly the cycloolefin resin film or the acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the polarizer is further improved. The reason for this is that, in the above range, the curl balance of the entire polarizing plate is improved, and the curling of the polyester resin film occurs with the lapse of time at a high temperature, or the fine curling that occurs in different positions in the polarizing plate plane depending on the location. Is estimated to be suppressed. The above mechanism is based on a guess, and its correctness does not affect the technical scope of the present invention.

[Light reflective particles]
The ionizing radiation-curable resin composition may further include light reflective particles. Since the light-reflective particles do not transmit ultraviolet light, if the hard coat layer contains the light-reflective particles, the function of blocking ultraviolet light is further improved.

  Such light-reflective particles are not particularly limited, and for example, metal particles, metal oxide particles, and coating particles having a light-reflective coating layer formed on the surface of core particles are preferably used.

Examples of the metal constituting the metal particles include Au, Ag, Cu, Al, Fe, Ni, Pd, and Pt. Examples of the metal oxide constituting the metal oxide particles include tin oxide (SnO ₂ ), antimony oxide (Sb ₂ O ₅ ), antimony tin oxide (ATO) (for example, ammostine-doped tin oxide), and indium tin Oxides (ITO), aluminum zinc oxide (AZO), fluorinated tin oxide (FTO), ZnO, and the like can be given. Examples of the coating particles include conventionally known particles having a configuration in which a light-reflective coating layer is formed on the surface of a core particle. The core particles are not particularly limited, and include, for example, inorganic particles such as colloidal silica particles and silicon oxide particles, polymer particles such as fluororesin particles, acrylic resin particles, and silicone resin particles, and organic-inorganic composite particles. The material constituting the light-reflective coating layer is not particularly limited, and examples thereof include the above-mentioned metals or alloys thereof, and the above-described metal oxides.

  Among these, metal oxide particles are preferable, and antimony tin oxide (ATO) particles are more preferable.

  The average particle diameter of the light-reflective particles is preferably from 1 to 15 μm, more preferably from 2 to 10 μm, even more preferably from 2 to 8 μm. When the average particle diameter is 1 μm or more, the scratch resistance of the hard coat layer becomes better, and when the average particle diameter is 15 μm or less, the thickness of the hard coat layer can be reduced and the thickness can be reduced. The average particle size of the light-reflective particles can be determined using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM).

  Commercial products may be used as the light reflective particles. As a commercially available product, for example, ELCOM NY-1019ATV manufactured by Catalyst Kasei Kogyo Co., Ltd., which is a 20% by mass modified alcohol dispersion of antimony-doped tin oxide, may be mentioned.

  The light reflective particles can be used alone or in combination of two or more.

  In the present specification, the “thickness of the hard coat layer” in the case of a hard coat layer containing light-reflective particles means the thickness of a portion that does not include particles projected from the layer.

  The content of the light-reflective particles is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, and still more preferably 5 to 15 parts by mass with respect to 100 parts by mass of the ionizing radiation-curable compound. The content of the ionizing radiation-curable compound in the cured product of the ionizing radiation-curable resin composition is substantially the same as the content of the ionized radiation-curable compound in the cured product.

[Other additives]
Other additives in the ionizing radiation-curable resin composition include fillers such as anti-wear agents, matting agents, and scratch-resistant fillers, release agents, dispersants, leveling agents, and hindered amine light stabilizers (HALS). Etc. may be included.

[Thickness]
The thickness of the hard coat layer can be appropriately selected depending on the use and required characteristics of the polarizing plate according to one embodiment of the present invention, but is preferably 1 to 30 μm, more preferably 2 to 20 μm, still more preferably 2 to 10 μm. It is particularly preferable that the thickness be 5 μm. Within this range, the ability to cut ultraviolet rays is further improved, and cracks generated in a polarizer protective film, particularly a cycloolefin resin film or an acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular-shaped punching. The thickness of the hard coat layer can be calculated, for example, by measuring the thickness at 20 locations from an image of a cross section taken using a scanning transmission electron microscope (STEM) and by averaging the values at 20 locations. The acceleration voltage of the STEM is preferably 10 kv to 30 kV, and the observation magnification of the STEM is preferably 1000 to 7000 times.

  The ratio of the thickness (μm) of the hard coat layer to the thickness (μm) of the later-described cycloolefin resin film or acrylic resin film (thickness of hard coat layer (μm) / thickness of cycloolefin resin film or acrylic resin film (μm)) ) Is preferably 0.002 to 1, more preferably 0.05 to 0.9, still more preferably 0.08 to 0.5, and 0.08 to 0.4. It is particularly preferable that the ratio be 0.1 to 0.4, and it is extremely preferable that the ratio be 0.1 to 0.4. Within this range, cracks generated in the polarizer protective film, particularly the cycloolefin resin film or the acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the polarizer is further improved. The reason for this is that, in the above range, the curl balance of the entire polarizing plate is improved, and the curling of the polyester resin film occurs with the lapse of time at a high temperature, or the fine curling that occurs in different positions in the polarizing plate plane depending on the location. Is estimated to be suppressed. The above mechanism is based on a guess, and its correctness does not affect the technical scope of the present invention.

[Method of forming hard coat layer]
The hard coat layer is coated on a polyester resin film with a hard coat layer coating solution containing an ionizing radiation-curable resin composition in an amount to have a desired thickness after curing, and drying is performed as necessary. Irradiation and curing.

  The method and conditions for preparing, coating, drying, and irradiating ionizing irradiation with the coating solution for the hard coat layer are not particularly limited, and a known method can be appropriately selected and used.

  The coating solution for the hard coat is composed of an ionizing radiation-curable compound, an ultraviolet absorber, and optionally used light-reflective particles and other additives, which are homogeneously mixed at a predetermined ratio in a solvent as required. Can be prepared.

  Examples of the solvent include, but are not particularly limited to, water, hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone), and esters. (Methyl acetate, ethyl acetate, methyl lactate), glycol ethers, other organic solvents, and the like, or a mixture thereof.

  The content of the solvent in the hard coat layer coating solution is not particularly limited, but is preferably 10 to 80% by mass, more preferably 20 to 80% by mass, and more preferably 20 to 80% by mass with respect to the total mass of the coating solution. The content is more preferably 60% by mass, particularly preferably 40 to 60% by mass, and most preferably 50 to 60% by mass.

  The hard coat layer coating solution thus prepared is coated on a polyester resin film or on the surface of a functional layer provided on a polyester resin film by a die coat, a bar coat, a roll coat, a slit coat, a slit reverse coat, a reverse roll. An uncured resin layer is formed by applying a coat, a gravure coat or the like, and drying it as necessary.

  Although the drying conditions after the application are not particularly limited, for example, the drying temperature is preferably 70 to 110 ° C., and the drying time is preferably 30 seconds to 5 minutes.

  Next, the uncured resin layer is cured by irradiating the uncured resin layer with ionizing radiation such as an electron beam or an ultraviolet ray. As the irradiation method of the ionizing radiation, it is preferable to irradiate the uncured resin layer from the side opposite to the substrate side to cure the coating film.

  When ultraviolet rays are used as ionizing radiation, those containing ultraviolet rays having a wavelength of 190 to 380 nm are usually emitted. The ultraviolet light source is not particularly limited, and for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a carbon arc lamp and the like are used.

At this time, the conditions such as the irradiation wavelength, the illuminance, and the light amount of the ultraviolet ray vary depending on the type of the ionizing radiation-curable compound and the polymerization initiator to be used, and thus those skilled in the art can appropriately adjust the conditions. For example, the irradiation energy amount is preferably 50 to 1500 mJ / cm ² .

(Cycloolefin resin film or acrylic resin film)
A polarizing plate according to one embodiment of the present invention has a cycloolefin resin film or an acrylic resin film containing an ultraviolet absorber.

  The cycloolefin resin film and the acrylic resin film represent films containing a cycloolefin polymer and a (meth) acrylic polymer, respectively, in an amount of 50% by mass or more based on the total mass of the film. If the content of the cycloolefin polymer or the (meth) acrylic polymer is less than 50% by mass, the film may not be able to obtain excellent water resistance derived from the cycloolefin polymer or the (meth) acrylic polymer. From the same viewpoint, the lower limit of the content of the cycloolefin polymer and the (meth) acrylic polymer is preferably 80% by mass or more, and more preferably 90% by mass or more. The upper limit of the content of the cycloolefin polymer and the (meth) acrylic polymer is preferably 98% by mass or less, more preferably 97% by mass or less. When the content is within this range, the cycloolefin resin film and the acrylic resin film can contain the ultraviolet absorber in a more appropriate amount, and the ultraviolet ray cutting ability is further improved. In addition, cracks generated in a polarizer protective film, particularly a cycloolefin resin film or an acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the polarizer is further improved. In addition, even when the film contains both the cycloolefin polymer and the (meth) acrylic polymer and the cycloolefin polymer and the (meth) acrylic polymer alone do not satisfy the above range, the total If the mass is within the above range with respect to the total mass of the film, the film is included in the “cycloolefin resin film or acrylic resin film”.

  In the present specification, the “cycloolefin resin film” and the “acrylic resin film” are formed from a cycloolefin polymer alone or a composition containing the same, and a (meth) acrylic polymer alone or a composition containing the same, respectively. Film that can be formed, and does not include other functional layers.

  Among the cycloolefin resin film and the acrylic resin film, the cycloolefin resin film is more preferable. By using the cycloolefin resin film, cracks generated in the polarizer protective films disposed on both surfaces of the polarizer, particularly the cycloolefin resin film itself, are further reduced in a part of the plane of the polarizing plate at the time of irregular punching. Furthermore, after a lapse of time at a high temperature, the adhesion between the polarizer protective films, particularly the cycloolefin resin film itself, and the polarizer disposed on both surfaces of the polarizer is further improved.

[Cycloolefin polymer]
The cycloolefin polymer (cycloolefin resin), which is a raw material resin for the cycloolefin resin film, is not particularly limited, but is a (co) polymer obtained by polymerizing a cycloolefin monomer or a hydrogenated product thereof (hydrogenated polymer). ) And the like. Among these, a (co) polymer obtained by polymerizing a cycloolefin monomer represented by the following general formula (5) or a hydrogenated product thereof (hydrogenated polymer) is preferable. 5) A (co) polymer obtained by ring-opening (co) polymerizing the cycloolefin monomer represented by 5) or a hydride (hydrogenated polymer) obtained by hydrogenating the (co) polymer. More preferably, there is.

(Wherein, R ^{16 to} R ¹⁹ each independently represent a hydrogen atom, a hydrocarbon group, a halogen atom, a hydroxy group, an ester group, an alkoxy group, a cyano group, an amide group, an imide group, a silyl group, or a polar group or A hydrocarbon group substituted with a polar group, provided that two or more of R ^{16 to} R ¹⁹ may be bonded to each other to form an unsaturated bond, a monocyclic ring or a polycyclic ring; Alternatively, the polycyclic ring may have a double bond or form an aromatic ring, and R ¹⁶ and R ¹⁷ or R ¹⁸ and R ¹⁹ may form an alkylidene group. .P and m are each independently an integer of 0 or more.)
In the general formula (5), R ¹⁶ and R ¹⁸ are preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, further preferably hydrogen. An atom or a hydrocarbon group having 1 to 2 carbon atoms, particularly preferably a hydrogen atom. R ¹⁷ and R ¹⁹ are preferably a hydrogen atom or a monovalent organic group, and at least one of R ¹⁷ and R ¹⁹ represents a hydrogen atom or a polar group. Among these, it is preferable that one of R ¹⁷ and R ¹⁹ is a hydrogen atom and the other is a polar group. m is preferably an integer of 0 to 3, p is preferably an integer of 0 to 3, more preferably m + p = 0 to 4, further preferably m + p = 0 to 2, particularly preferably m = 1 and p = 0. It is. The specific monomer having m = 1 and p = 0 is preferable because the resulting cycloolefin polymer has a high glass transition temperature and excellent mechanical strength.

  Examples of the polar group of the specific monomer include a carboxy group, a hydroxy group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group, and a cyano group.These polar groups include a linking group such as a methylene group. And may be bonded via In addition, a hydrocarbon group to which a divalent organic group having a polarity such as a carbonyl group, an ether group, a silyl ether group, a thioether group, and an imino group is bonded as a linking group is also exemplified as the polar group. Among these, a carboxy group, a hydroxy group, an alkoxycarbonyl group (—COOR) or an alloxycarbonyl group is preferable, a carboxy group, an alkoxycarbonyl group or an alloxycarbonyl group is more preferable, and a carboxy group is further preferable.

Further, a monomer in which at least one of R ¹⁷ and R ¹⁹ is a polar group represented by the formula — (CH ₂ ) _n COOR has a high glass transition temperature, a low hygroscopicity, and a variety of materials. It is preferable in that it has excellent adhesion.

  In the above formula relating to the specific polar group, R is preferably a hydrocarbon having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 2 carbon atoms. And the hydrocarbon group is most preferably an alkyl group.

  Other specific examples of the cycloolefin monomer include, but are not particularly limited to, for example, cyclobutene, cyclopentene, cycloheptene, cyclooctene, dicyclopentadiene, norbornene, and the like. In addition, the cycloolefin monomer can be used alone or in combination of two or more.

  The number of carbon atoms in the cycloolefin ring is preferably from 4 to 20, and more preferably from 5 to 12.

  As the (co) polymer or its hydrogenated product (hydrogenated polymer) obtained by polymerizing the cycloolefin monomer represented by the above general formula (5), a partial structure derived from the following general formula (6) Preferably, the cycloolefin polymer has the following formula:

In the general formula (6), R ¹⁸ and R ¹⁹ are the same as those described in the general formula (5).

The molecular weight of the cycloolefin polymer is preferably in the range of 0.2 to 5 dL / g, more preferably 0.3 to 3 dL / g, particularly preferably 0.4 to 1.5 dL / g in intrinsic viscosity [η] _inh. It is. The number average molecular weight (Mn) of the cycloolefin polymer is preferably from 8,000 to 100,000, more preferably from 10,000 to 80,000, and still more preferably from 12,000 to 50,000. The weight average molecular weight (Mw) of the cycloolefin polymer is preferably from 20,000 to 300,000, more preferably from 30,000 to 250,000, and still more preferably from 40,000 to 200,000. When the intrinsic viscosity [η] _inh , the number average molecular weight and the weight average molecular weight are within the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties, and moldability of the cycloolefin polymer film as a cycloolefin resin film are obtained. Is good. The number average molecular weight and the weight average molecular weight can be determined in terms of polystyrene from the results of measurement by gel permeation chromatography (GPC).

  Commercial products may be used as the cycloolefin polymer. Examples of commercially available products include ARTON (registered trademark) G, F, F4520, R, RX manufactured by JSR Corporation, ZEONOR (registered trademark) ZF14, ZF16, and ZEONEX (registered trademark) 250, 280 manufactured by Zeon Corporation. And the like.

  Cycloolefin polymers can be used alone or in combination of two or more.

[(Meth) acrylic polymer]
The (meth) acrylic polymer (acrylic resin), which is a raw material resin of the acrylic resin film, is not particularly limited, but is preferably a (co) polymer of (meth) acrylate or a derivative thereof, and particularly preferably (meth) acrylate. More preferably, it is a (co) polymer.

  The (meth) acrylic polymer is not particularly limited, but the structural unit derived from methyl methacrylate is 51 to 100% by mass, assuming that the entire polymer is 100% by mass, and other monomers copolymerizable therewith. Those having a structural unit derived from 0 to 49% by mass are preferable from the viewpoint of obtaining a high-quality optical film. Among these, those having 95 to 100% by mass of a structural unit derived from methyl methacrylate and 0 to 5% by mass of a structural unit derived from another monomer copolymerizable therewith are more preferable.

  The other monomer copolymerizable with methyl methacrylate is not particularly limited. For example, α, such as methyl acrylate, an alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms, and (meth) acrylic acid. Unsaturated group-containing dicarboxylic acids such as β-unsaturated acid, maleic acid, fumaric acid, and itaconic acid; aromatic vinyl compounds such as styrene and α-methylstyrene; α, β-unsaturated such as (meth) acrylonitrile Examples thereof include nitrile, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride and the like. These can be used alone or in combination of two or more monomers as a copolymer component.

  Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate or 2-ethylhexyl acrylate is preferred from the viewpoint of heat decomposition resistance and fluidity of the copolymer, and methyl acrylate or n -Butyl acrylate is more preferred, and methyl acrylate is even more preferred.

  (Meth) acrylic polymers that can form highly transparent films with little change in performance even in high-temperature, high-humidity environments contain alicyclic alkyl groups as copolymerization components, or are mainly polymerized by intramolecular cyclization. It is preferably a (meth) acrylic polymer having a cyclic structure formed in the chain. Examples of (meth) acrylic polymers having a cyclic structure in the molecular main chain include, for example, (meth) acrylic polymers containing lactone ring-containing polymers described in paragraphs 0195 to 0202 of JP-A-2012-133078. Polymers are mentioned, and preferable polymer compositions and synthesis methods are described in, for example, JP-A-2012-066538 and JP-A-2006-171664. Further, as another preferred embodiment, a polymer containing glutaric anhydride as a copolymer component is cited, and the copolymer component and a specific synthesis method are described in, for example, JP-A-2004-070296.

  The lower limit of the weight average molecular weight (Mw) of the (meth) acrylic polymer is preferably 80,000 or more, more preferably 100,000 or more. Within this range, the content of the organic solvent in the dope can be further reduced, the drying time can be further reduced, and the surface condition of the film can be further improved. The upper limit of the weight average molecular weight (Mw) of the (meth) acrylic polymer is preferably 4,000,000 or less. Within this range, better suitability for solution casting can be realized, and compatibility with an organic solvent and additives can be improved during the preparation of the dope. The weight average molecular weight is a value determined by gel permeation chromatography (GPC) in terms of polystyrene.

  The method for producing the (meth) acrylic polymer is not particularly limited, and a known method such as suspension polymerization, emulsion polymerization, bulk polymerization, or solution polymerization can be used.

  As the (meth) acrylic polymer, a commercially available product may be used. Commercially available products include, for example, Delpet (registered trademark) 60N and 80N manufactured by Asahi Kasei Chemicals Corporation, and Dianal (registered trademark) BR52, BR80, BR83, BR85, BR88, manufactured by Mitsubishi Rayon Co., Ltd., Denki Kagaku Kogyo Co., Ltd. And the like K75.

  The (meth) acrylic polymer can be used alone or in combination of two or more.

[UV absorber]
The cycloolefin resin film or the acrylic resin film contains an ultraviolet absorber. As the ultraviolet absorber, the same one as the ultraviolet absorber contained in the above-described hard coat layer can be used.

  Among these, from the viewpoint of ultraviolet absorption, a benzophenone-based compound, a benzotriazole-based compound or a triazine-based compound is preferable, and a benzotriazole-based compound or a triazine-based compound is more preferable.

  The benzophenone-based compound is not particularly limited, and examples thereof include 2,2-dihydroxy-4,4-dimethoxybenzophenone.

  The benzotriazole-based compound is not particularly limited, but is preferably a compound represented by the general formula (1), and more preferably a compound represented by the general formula (2). Further, the benzotriazole compound may be a multimer containing the compound of the general formula (1) or the general formula (2) as a partial structure. Among them, benzotriazole-based compounds include methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate and methyl 3- (3- (2H- Reaction product of benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate with polyethylene glycol (methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert- Addition of polyethylene glycol with butyl-4-hydroxyphenyl) propionate or methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate via polyethylene glycol Multimers such as dimers (for example, Compound A) or a mixture containing them), 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4-1,1,3,3-tetramethyl Butyl) phenol (Exemplified Compound 1) and 2- (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) benzotriazole (Exemplified Compound 6) are particularly preferred.

  The triazine-based compound is not particularly limited, but is preferably a compound represented by the general formula (3). Among these, the triazine-based compound is more preferably a hydroxyphenyltriazine (HPT) -based compound, and particularly preferably the exemplified compound 17 or the exemplified compound 18.

  As the ultraviolet absorber, a polymer ultraviolet absorber may be used. The polymer UV absorber is preferably a polymer UV absorber having a benzophenone group, a triazine group or a benzotriazole group, and is preferably a polymer UV absorber having a triazine group or a benzotriazole group. More preferably, it is a polymer ultraviolet absorber having a benzotriazole group. The polymer type ultraviolet absorber having a benzotriazole group is not particularly limited, and includes, for example, a polymer type ultraviolet absorber represented by the general formula (4).

  Note that these details are the same as those of the ultraviolet absorber contained in the above-described hard coat layer, and thus description thereof is omitted here.

  As an ultraviolet absorber contained in a cycloolefin resin film or an acrylic resin film, it is used to reduce the failure at the time of abnormal punching of a polarizing plate and to improve the adhesion between the polarizer protective film and the polarizer after aging at a high temperature. From the viewpoint, a compound having one benzotriazole skeleton in the molecule or a compound having one triazine skeleton in the molecule is particularly preferable, and a compound having one triazine skeleton in the molecule is particularly preferable. Among these, from the viewpoint of further improving the adhesion between the polarizer protective film and the polarizer after aging at high temperatures, a low-polarity triazine-based compound having one triazine skeleton in the molecule is extremely preferable. . The low-polarity triazine-based compound having one triazine skeleton in the molecule is not particularly limited, but is preferably a low-polarity hydroxyphenyltriazine (HPT) -based compound, and is the above-mentioned exemplified compound 18. Is more preferred.

  The molecular weight of the UV absorber contained in the cycloolefin resin film or acrylic resin film reduces the failure of the polarizing plate when punching out irregular shapes, and improves the adhesion between the polarizer protective film and the polarizer after aging at high temperatures. From the viewpoint of, it is preferable that it is 250 or more and less than 1,000. Among these ranges, the molecular weight of the ultraviolet absorber is more preferably 300 or more and less than 1,000 from the viewpoint of further improving the adhesion between the polarizer protective film and the polarizer after aging at a high temperature. , 500 or more and less than 1,000, and particularly preferably 800 or more and less than 1,000. The molecular weight of the ultraviolet absorber is a value calculated from the sum of the atomic weights of the ultraviolet absorbers other than the polymer ultraviolet absorber, and the molecular weight of the polymer absorber is determined by gel permeation chromatography (GPC). Weight-average molecular weight determined in terms of polystyrene as described above.

  The ultraviolet absorber contained in the cycloolefin resin film or the acrylic resin film can be used alone or in combination of two or more.

  The lower limit of the content of the ultraviolet absorber contained in the cycloolefin resin film or the acrylic resin film is preferably 2 parts by mass or more, and more preferably 3 parts by mass or more with respect to 100 parts by mass of the cycloolefin polymer or the (meth) acrylic polymer. Is more preferable. Within this range, the ability to cut ultraviolet rays is further improved. In addition, cracks generated in a polarizer protective film, particularly a cycloolefin resin film or an acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the polarizer is further improved. Further, the upper limit of the content of the ultraviolet absorber contained in the cycloolefin resin film or the acrylic resin film is preferably 20 parts by mass or less based on 100 parts by mass of the cycloolefin polymer or the (meth) acrylic polymer. Parts or less is more preferable. Within this range, cracks generated in the polarizer protective film, particularly the cycloolefin resin film or the acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the polarizer is further improved.

[Fine particles]
The cycloolefin resin film or the acrylic resin film may contain fine particles (matting agent) as long as the effects of the present invention are not impaired. The fine particles have an action of giving a slipperiness or the like to the surface of the cycloolefin resin film or the acrylic resin film. The fine particles may be composed of an inorganic compound or a resin. As the fine particles, silicon dioxide fine particles are preferable in that the turbidity of the film can be reduced.

  As the fine particles of silicon dioxide, commercially available products can be used. Commercial products include Aerosil (registered trademark) R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600, etc., manufactured by Nippon Aerosil.

  The upper limit of the content of the fine particles is preferably 0.01 to 2 parts by mass, more preferably 0.05 to 1 part by mass, based on 100 parts by mass of the cycloolefin polymer or the (meth) acrylic polymer. More preferably, the amount is 0.1 to 0.5 part by mass.

[Other additives]
A cycloolefin resin film or an acrylic resin film may be used, for example, as long as the effects of the present invention are not impaired, for example, JP-A-9-221577, a specific hydrocarbon-based resin described in JP-A-10-287732, a known resin. Other additives such as a thermoplastic resin, a thermoplastic elastomer, a rubbery polymer, and rubber particles may be included.

[Thickness]
The lower limit of the thickness of the cycloolefin resin film or the acrylic resin film is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. Within this range, the ability to cut ultraviolet rays is further improved. In addition, cracks generated in a polarizer protective film, particularly a cycloolefin resin film or an acrylic resin film, are reduced more in a part of the plane of the polarizing plate at the time of irregular punching. In addition, the upper limit of the thickness of the cycloolefin resin film or the acrylic resin film is preferably 500 μm or less, more preferably 150 μm or less, further preferably 110 μm or less, and particularly preferably 40 μm or less. . Within this range, the effect of reducing cracks generated in the polarizer protective film, particularly the cycloolefin resin film or the acrylic resin film, is exhibited well in a part of the plane of the polarizing plate at the time of irregular punching, and further thinning is achieved. Is achieved.

[Retardation film]
The cycloolefin resin film or the acrylic resin film may be a retardation film.

  The retardation film is not particularly limited, but preferably satisfies the retardation condition represented by the following (a) or (b). The retardations Ro and Rth of the retardation film are respectively defined by the following equations.

Formula (I) Ro = (nx−ny) × d
Formula (II) Rth = {(nx + ny) / 2−nz} × d
(However, nx represents the refractive index in the direction x where the refractive index becomes maximum in the in-plane direction of the film, ny represents the refractive index in the direction y orthogonal to the direction x in the in-plane direction of the film, nz represents the refractive index in the thickness direction z of the film, and d (nm) represents the thickness of the film).

  (A) The retardation of the retardation film is preferably such that the in-plane retardation Ro (590) measured at a wavelength of 590 nm under the conditions of 23 ° C. and 55% RH is 20 to 100 nm, and the retardation in the thickness direction. The retardation Rth (590) is preferably from 70 to 300 nm. A protective film having a retardation in the above range is suitable as a retardation film for a VA-type liquid crystal cell, for example.

The in-plane retardation Ro and the thickness-direction retardation Rth of the retardation film with respect to light having a wavelength of 590 nm in an environment of 23 ° C. and 55% RH can be measured by the following methods:
1) Humidify the retardation film at 23 ° C. and 55% RH. The average refractive index of the retardation film after humidity control is measured with an Abbe refractometer or the like;
2) Measure Ro using a KOBRA-21DH (manufactured by Oji Scientific Instruments) when a light having a measurement wavelength of 590 nm is incident on the retardation film after humidity control in parallel to the normal line of the film surface;
3) By KOBRA-21ADH, the measurement wavelength is 590 nm from the angle of θ (incident angle (θ)) with respect to the normal to the surface of the retardation film, with the in-plane slow axis as the tilt axis (rotation axis). The retardation value R (θ) at the time when the above light is incident is measured. The measurement of the retardation value R (θ) can be performed at six points every 10 ° in a range of 0 to 50 °. The in-plane slow axis refers to an axis having the maximum refractive index in the plane of the film, which can be confirmed by KOBRA-21ADH;
4) nx, ny and nz are calculated from the measured Ro and R (θ), the above-mentioned average refractive index and the film thickness by KOBRA-21ADH, and Rth at a measurement wavelength of 590 nm is calculated. The measurement of retardation can be performed at 23 ° C. and 55% RH.

  (B) The retardation of the retardation film is preferably such that the in-plane retardation Ro is substantially λ / 4. In the present specification, the fact that the in-plane retardation Ro of the film is substantially λ / 4 means that the in-plane retardation Ro (23 ° C., 55% RH) is measured at a wavelength of 550 nm. 550) is within the range of 120 to 180 nm.

  When the in-plane retardation Ro of the film is substantially λ / 4, the retardation film has an in-plane retardation Ro measured at a wavelength of 550 nm at 23 ° C. and 55% RH. The value of the ratio of the in-plane retardation Ro (450) measured at a wavelength of 450 nm to (550) (Ro (450) / Ro (550)) is in the range of 0.72 to 1.05. Is preferred. Further, the retardation film has an in-plane retardation Ro (550) measured at a wavelength of 550 nm relative to an in-plane retardation Ro (650) measured at a wavelength of 650 nm under the conditions of 23 ° C. and 55% RH. ) Is preferably in the range of 0.83 to 1.05. (Ro (550) / Ro (650))

  The retardation Ro of the retardation film in the in-plane direction with respect to light having a wavelength of 450 nm, 550 nm, and 650 nm under an environment of 23 ° C. and 55% RH is determined by an automatic birefringence meter AxoScan (Axo Scan Mueller Matrix Polarimeter: Axome). (Manufactured by Trix Co., Ltd.) to measure the birefringence at each wavelength.

  A retardation film having an in-plane retardation Ro of substantially λ / 4 can be used as a λ / 4 retardation film. The λ / 4 retardation film refers to a film having a function of converting linearly polarized light having a specific wavelength into circularly polarized light or converting circularly polarized light into linearly polarized light.

  Circularly polarizing plates can be obtained by laminating such that the angle between the in-plane slow axis of the λ / 4 retardation film and the transmission axis of the polarizer is substantially 45 °. In the present specification, “substantially 45 °” means within a range of 45 ± 5 °. The angle between the in-plane slow axis of the λ / 4 retardation film and the transmission axis of the polarizer is preferably in the range of 41 to 49 °, and more preferably in the range of 42 to 48 °. , 43-47 °, more preferably 44-46 °.

  In addition, the phase difference of the above (a) and the above (b) is based on the type of the cycloolefin polymer or the (meth) acrylic polymer contained in the cycloolefin resin film or the acrylic resin film, the type and content of the additive, the stretching method, It can be controlled by the stretching conditions such as the stretching ratio and the stretching ratio, and the thickness of the film.

[Function layer]
In the polarizing plate according to one embodiment of the present invention, the cycloolefin resin film or the acrylic resin film may have a functional layer. Each functional layer may be provided directly on the surface of the cycloolefin resin film or the acrylic resin film, or may be provided on the cycloolefin resin film or the acrylic resin film via another functional layer. As the functional layer, a layer generally provided in a polarizing plate or a polarizer protective film can be appropriately selected. Examples of the functional layer include a hard coat layer, an easily adhesive layer, an antiglare layer, an antireflection layer, a low reflection layer, a low reflection antiglare layer, an antireflection antiglare layer, an antistatic layer, a silicone layer, an adhesive layer, and an anti-glare layer. Examples include a stain layer, a fingerprint-resistant layer, a water-repellent layer, and a blue-cut layer.

[Method for producing cycloolefin resin film or acrylic resin film]
The method for producing the cycloolefin resin film or the acrylic resin film is not particularly limited, and a known method can be used. Among these, it is preferable to use the solution casting method or the melt casting method, and it is more preferable to use the solution casting method from the viewpoint that the amount of the ultraviolet absorber reduced due to volatilization and decomposition during the production process is reduced. In a cycloolefin resin film or an acrylic resin film produced by a solution casting method, the ultraviolet ray cut ability is further improved. Further, in the film, cracks generated in a polarizer protective film, particularly a cycloolefin resin film or an acrylic resin film, are further reduced in a part of the plane of the polarizing plate at the time of the irregular punching. Further, in the films, after the aging at a high temperature, the adhesion between these films and the polarizer is further improved.

  The solution casting method is a method in which a solution in which a cycloolefin polymer or a (meth) acrylic polymer, an ultraviolet absorber and other additives that can be optionally added are dissolved is cast on a substrate, dried on the substrate, and then dried. In this method, the (web) is peeled off, and after the peeling, the web is further dried to form a film. In the melt casting method, a resin composition containing a cycloolefin polymer or a (meth) acrylic polymer, an ultraviolet absorber and other additives that can be optionally added is heated and melted, cast on a substrate, and cooled and solidified. This is a method of forming a film. In these production methods, stretching may be performed as needed during or after film formation.

  Hereinafter, the solution casting method, which is a preferred method for producing a cycloolefin resin film or an acrylic resin film, will be described in detail, but the production method is not limited thereto.

  The method for producing a cycloolefin resin film or an acrylic resin film by a solution casting method is a process of stretching in a drying process during film formation, or unwinding a film (film raw material) wound up after film formation and then stretching. It is more preferable to have a step of performing

Cycloolefin resin film or acrylic resin film,
1) a step of dissolving each of the above components in a solvent to prepare a dope solution;
2) casting the dope on an endless substrate;
3) a step of drying the cast dope and then peeling it off to obtain a film (web);
4) a step of drying and, if necessary, stretching the web (film drying step);
It is preferred to be manufactured through.

Further, after the above 4), optionally,
5) a step of unwinding the film raw film wound up after film formation and then stretching (hereinafter, also referred to as “post-film formation stretching”) (post-film formation stretching step);
May be provided.

  Examples of the solvent used in the above step 1) include: chlorinated solvents such as chloroform and dichloromethane; aromatic solvents such as toluene, xylene, benzene, and a mixed solvent thereof; methanol, ethanol, and propanol (n-propanol). , Isopropanol), butanol (n-butanol, isobutanol, 2-butanol, tert-butanol); alcohol solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, dimethylformamide, dimethyl sulfoxide, dioxane, cyclohexanone, Tetrahydrofuran, acetone, methyl ethyl ketone (MEK), ethyl acetate, diethyl ether;

  In the solution casting method, the concentration of the cycloolefin polymer or the (meth) acrylic polymer in the dope is preferably as high as possible because the drying load after casting onto the substrate can be reduced. Load increases, and the filtration accuracy deteriorates. The concentration for satisfying both is preferably 10 to 35% by mass, and more preferably 15 to 35% by mass. The substrate in the casting step is preferably one whose surface is mirror-finished, such as a stainless steel belt (stainless belt) or a drum whose surface is plated with a casting.

  As for the dope temperature at the time of casting, it is preferable that the dope has fluidity such that the dope can be cast and the solvent in the dope has a boiling point or lower. The doping temperature depends on the solvent used, but is generally preferably 0 to 35 ° C, more preferably 20 to 35 ° C.

  The width of the cast can be in the range of 1-4 m. The surface temperature of the substrate in the casting step is set to a temperature from -50 ° C to a temperature at which the solvent does not boil and foam. A higher temperature is preferable because the drying speed of the web can be increased. When the temperature is within this temperature range, there is no fear that the web foams or the flatness is deteriorated.

  The preferred substrate temperature is appropriately determined within the range of 0 to 100 ° C, and more preferably within the range of 5 to 30 ° C. Alternatively, it is also a preferable method to gel the web by cooling the substrate and to peel the web from the drum while containing a large amount of residual solvent. The method of controlling the temperature of the substrate is not particularly limited, and includes a method of blowing hot air or cold air, and a method of bringing hot water into contact with the back side of the substrate. The method using hot water is preferable from the viewpoint that the time required for the temperature of the base to become constant is short because heat is efficiently transferred. In addition, when using hot air, consider the temperature decrease of the web due to the latent heat of evaporation of the solvent, use hot air at the boiling point of the solvent or higher, and use air at a temperature higher than the target temperature while preventing foaming. There is. In this case, it is preferable that the temperature of the substrate and the temperature of the drying air are changed from the casting to the peeling to efficiently perform the drying.

  From the viewpoint that the cycloolefin resin film or the acrylic resin film shows good flatness, the amount of the residual solvent when the web is peeled off from the substrate is preferably in the range of 10 to 150% by mass, more preferably 20 to 40% by mass. % By mass or in the range of 60 to 130% by mass, more preferably in the range of 20 to 30% by mass or 70 to 120% by mass.

The amount of residual solvent is defined by the following formula:
Residual solvent amount (% by mass) = {(M−N) / N} × 100
M is the mass of the sample collected at any time during or after the production of the web or film, and N is the mass of M after heating at 115 ° C. for 1 hour.

  In the drying step, it is preferable to remove the web from the substrate and further dry the web to reduce the residual solvent amount of the obtained cycloolefin resin film or acrylic resin film. The residual solvent amount of the cycloolefin resin film or the acrylic resin film is preferably 1% by mass or less, more preferably 0.1% by mass or less, and still more preferably 0 to 0.01% by mass.

  The film drying step is not particularly limited, but generally employs a roller drying method (a method in which the web is alternately passed through a number of rollers arranged vertically and drying) or a method in which the web is dried while being conveyed by a tenter.

  When the web is stretched in the film drying step, the residual solvent of the web at the start of stretching is preferably 10% by mass or less, and more preferably 5% by mass or less, from the viewpoint of suppressing an increase in haze. As a method of keeping the residual solvent at the start of stretching at 10% by mass or less, a method of removing the cast dope from the substrate and providing the drying step in the process of transporting the dope to evaporate the solvent is preferable.

  The method of stretching the web is not particularly limited, and a method is used in which a plurality of rolls are provided with a peripheral speed difference, and the web is stretched in the MD direction using the difference in the peripheral speed between the rolls. In the method of stretching by extending the distance between the clips and pins in the MD direction (transport direction), fixing both ends of the web with clips and pins using a tenter, and setting the distance between the clips and pins in the TD direction (with respect to the transport direction) A method of extending and stretching in the vertical direction), a method of simultaneously extending and stretching the intervals of the clips and pins in the MD direction and the TD direction (direction perpendicular to the transport direction), or the like can be employed alone or in combination. . Among these, stretching in the TD direction is preferably performed by a tenter. The type of the tenter may be a pin tenter or a clip tenter. That is, the film may be stretched in the TD direction, may be stretched in the MD direction, or may be stretched in both directions. Further, when stretching is performed in both directions, simultaneous stretching may be performed or sequential stretching may be performed.

  In the case of the so-called tenter method, it is preferable to drive the clip portion by the linear drive method since smooth stretching can be performed and the risk of breakage can be reduced.

  In the stretching step, the stretching ratio in the direction in which the stretching ratio is higher in the TD direction or the MD direction is preferably 1 to 100% (1.01 to 2.00 times), more preferably 5 to 80% (1.05%). To 1.80 times), and more preferably 12 to 60% (1.12 to 1.60 times). For example, in the case of stretching in biaxial directions orthogonal to each other, it is preferably 0 to 100% (1.00 to 2.00 times), more preferably 0 to 60% (1.00 to 1.00) in the transport direction (MD direction). 1.60 times), preferably 5 to 70% (1.05 to 1.70 times), more preferably 10 to 70% (1.10 to 1.70 times) in the width direction (TD direction). The stretching ratio (%) is defined by the following equation. Here, when manufacturing a retardation film having the retardation described in the above (a), it is preferable to set the retardation film in the width direction (TD direction) to 20 to 70% (1.20 to 1.70 times).

Stretching rate (%) = {((stretching direction) length of film after stretching− (stretching direction) length of film before stretching) / (stretching direction) length of film before stretching} × 100
The stretching temperature can be in the range of 120-180 ° C, preferably 140-180 ° C, more preferably 145-165 ° C.

  Further, as a stretching method in the film drying step, oblique stretching using a tenter capable of oblique stretching may be performed.

  In addition, as the oblique stretching method in the film drying step and the stretching step after film formation, a known method can be appropriately adopted. For example, a method described in paragraphs 0110 to 0124 of JP-A-2016-212146 and the like can be employed after appropriately modifying the method, but the oblique stretching method is not limited thereto.

  The cycloolefin resin film or the acrylic resin film is obtained by drying the web in the film drying step.

  It is preferable that the cycloolefin resin film or the acrylic resin film after film formation is wound up and formed into a roll (film roll).

  As other steps in the solution casting method, various steps that can be included in a known solution casting method can be appropriately adopted. For example, steps similar to those described in paragraphs 0109 to 0140 of JP-A-2012-48214 can be employed, but other steps are not limited thereto.

  As the melt casting method, a known method can be appropriately adopted. For example, the method described in paragraphs 0111 to 0116 of Japanese Patent No. 5550915, the method described in paragraphs 0224 to 0230 of JP-A-2006-153839, and the like can be adopted with appropriate modifications. . However, applicable melt casting methods are not limited to these.

  Further, after unwinding the film formed and wound by the above-described solution casting method or the melt casting method, and then stretching (stretching after film formation), the cycloolefin resin film or acrylic A resin film may be manufactured.

  The stretching method after film formation is not particularly limited, and a known method can be used. For example, a method similar to the stretching described in the film drying step in the solution casting method described above can be preferably used. In this case, the details of the stretching method after film formation are described in the above-mentioned film drying step, in which the amount of residual solvent at the start of stretching is read as the amount of residual solvent after the drying step, and the aforementioned web is read as a raw film film. Can be explained. The stretching temperature in stretching after film formation is not particularly limited, but the temperature of the preheating zone is within the range of Tg to (Tg + 30) ° C. with respect to the glass transition temperature Tg of the cycloolefin polymer or acrylic polymer. Is preferably set in the range of Tg to (Tg + 30) ° C., and the temperature of the cooling zone is preferably set in the range of (Tg−30) to Tg ° C.

(Polarizer)
A polarizer is an element that transmits only light having a polarization plane in a certain direction, and a typical polarizer currently known is a polyvinyl alcohol (PVA) -based polarizing film (polarizer). Polyvinyl alcohol-based polarizing films include those obtained by dyeing a polyvinyl alcohol-based film with iodine and those obtained by dyeing a dichroic dye.

  The polyvinyl alcohol-based polarizing film may be a film obtained by uniaxially stretching the polyvinyl alcohol-based film and then dyeing it with iodine or a dichroic dye (preferably a film further subjected to a durability treatment with a boron compound). A film obtained by dyeing a polyvinyl alcohol-based film with iodine or a dichroic dye and then uniaxially stretching the film (preferably, a film further subjected to a durability treatment with a boron compound) may be used. Further, a film produced by combining these may be used. The total stretching ratio of the uniaxial stretching is not particularly limited, but is preferably, for example, 5 to 10 times. The absorption axis of the polarizer is not particularly limited, but is preferably perpendicular to the longitudinal direction of the film or parallel to the stretching direction of the film.

  As the polyvinyl alcohol-based film, polyvinyl alcohol or modified polyvinyl alcohol can be used.

  A commercially available product may be used as the polyvinyl alcohol-based film. As a commercially available product, for example, Kuraray Co., Ltd. Kuraray Vinylon PE3000, PE6600, or the like can be used.

  Although it does not specifically limit as a modified polyvinyl alcohol, For example, the content of ethylene unit of 1-4 mol% of described in Unexamined-Japanese-Patent No. 2003-248123, 2003-342322, etc., polymerization degree 2000-4000, and Ken For example, ethylene-modified polyvinyl alcohol having a chemical degree of 99.0 to 99.99 mol% is used. Among them, an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73 ° C is preferably used.

  The thickness of the polarizer is not particularly limited, but is preferably 5 to 30 μm, and more preferably 10 to 20 μm from the viewpoint of reducing the thickness of the polarizing plate.

  As a method for producing the polarizer, a known method can be appropriately adopted. For example, the methods described in paragraphs 0133 to 0134 of JP-A-2014-010207 and the like can be adopted with appropriate changes, but the method for producing a polarizer is not limited thereto. .

<Manufacturing method of polarizing plate>
The polarizing plate according to one embodiment of the present invention can be manufactured by a general method.

  The polarizing plate is manufactured by laminating the above-mentioned polyester resin film with a hard coat layer, the above-mentioned cycloolefin resin film or acrylic resin film, and a polarizer. When these films further have a functional layer, the lamination may be performed by laminating the surface of the functional layer and the surface of the polarizer. That is, in the polarizing plate according to one embodiment of the present invention, the polyester resin film, and the cycloolefin resin film or the acrylic resin film are used as two polarizer protective films for protecting different surfaces of the polarizer, respectively. Become.

  The method for producing the polarizing plate is not particularly limited, and a known method can be applied. In producing a polarizing plate, a polyester resin film, a cycloolefin resin film, an acrylic resin film and a polarizer are a polyester resin film, a cycloolefin resin film or an acrylic resin film, or a corona discharge treatment for a functional layer having these, A publicly known surface treatment such as a plasma treatment and an alkali saponification treatment is performed, and lamination can be performed using a publicly known adhesive.

  For the surface treatment, a polyester resin film, a cycloolefin resin film or an acrylic resin film, on the side of the surface to be bonded to the polarizer, one or two or more functional layers such as an easy-adhesion layer on these film surfaces. When other functional layers are formed, surface treatment may be performed on the outermost surfaces of these functional layers.

  As the corona discharge treatment, a known method can be appropriately adopted. The corona discharge treatment is preferably performed, for example, by applying a high voltage of 1 kV or more between the electrodes under atmospheric pressure and discharging. By the corona treatment, an oxygen-containing polar group (hydroxy group, carbonyl group, carboxylic acid group, etc.) is generated on the surface of the film, and the surface is hydrophilized. The corona discharge treatment can be performed using a commercially available device manufactured by Kasuga Electric Co., Ltd. or Toyo Denki Co., Ltd. However, the corona discharge treatment is not limited to the above method and conditions.

  The surface of the polyester resin film on which the hard coat layer is not formed and the one surface of the cycloolefin resin film or the acrylic resin film, and the polarizer are a polyvinyl alcohol aqueous solution (water paste) or an active energy ray-curable adhesive. It is preferable that they are pasted by a known adhesive such as. Among these adhesives, it is preferable to use an aqueous solution of polyvinyl alcohol (water paste). The aqueous polyvinyl alcohol solution (water paste) is preferably a completely saponified polyvinyl alcohol aqueous solution (water paste). As the aqueous polyvinyl alcohol solution (water paste), a commercially available product may be used. Examples of commercially available products include PVA-117H manufactured by Kuraray Co., Ltd. and the like. In addition, when a functional layer (for example, an easy-adhesion layer or another functional layer) is formed on the surface of the polyester resin film, or the cycloolefin resin film or the acrylic resin film that is bonded to the polarizer, these layers may be used. What is necessary is just to bond the outermost surface of the functional layer and the polarizer with an adhesive.

  The polarizing plate according to one embodiment of the present invention can be suitably used for a display device having a free shape called a deformed panel or a free-form display (FFD). Accordingly, it is preferable that the polarizing plate according to one embodiment of the present invention be cut into an irregular shape in a free shape from the viewpoint of not only the conventional square and rectangular shapes but also the effect of the present invention can be more exerted. The cut shape of the deformed shape is not particularly limited, and examples thereof include a circular diameter, an elliptical shape, and a shape of a deformed panel as shown in FIG. However, the shape of the polarizing plate according to one embodiment of the present invention is not limited to this.

<Display device>
Another embodiment of the present invention is a display device including the polarizing plate according to one embodiment of the present invention.

  The polarizing plate according to one embodiment of the present invention is preferably used for a display device, and is more preferably used for a display device having a free shape called a modified panel or a freeform display (FFD). FIG. 1 is a schematic view illustrating an example of an odd-shaped panel to which the polarizing plate according to one embodiment of the present invention can be applied.

  In addition, the use of the polarizing plate according to one embodiment of the present invention is not particularly limited, but since the polarizer protective film has excellent water resistance, it is used in display devices such as in-vehicle applications used under severe conditions. It is preferably used. The display device is not particularly limited, but is preferably an organic EL element or a liquid crystal display device, and more preferably a liquid crystal display device. In a general transmission type liquid crystal display device, the liquid crystal display device has a liquid crystal cell in which liquid crystal is sandwiched between a transparent substrate and the other transparent substrate. It is preferable that the polarizing plate according to one embodiment of the present invention be arranged directly or via another member outside at least one of these transparent substrates.

  In the display device, the surface of the polarizing plate according to one embodiment of the present invention on the cycloolefin resin film or acrylic resin film side is on the display panel (liquid crystal cell, OLED cell) side with respect to the polarizer, and the polyester with the hard coat layer is provided. It is preferable that the films are arranged so as to face the polarizer on the side opposite to the display panel (liquid crystal cell, OLED cell).

  By incorporating the polarizing plate according to one embodiment of the present invention into a display device, various liquid crystal display devices with excellent visibility can be manufactured. The polarizing plate according to one embodiment of the present invention is a reflective, transmissive, transflective LCD, or various types of driving such as TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type), and IPS type. It is preferably used in LCDs of the system. Particularly, since it has excellent wavelength dispersibility, it is used for MVA type liquid crystal display devices and IPS type liquid crystal display devices, and a remarkable effect is recognized.

  In addition, the polarizing plate according to one embodiment of the present invention can be preferably used as a protective film for an image display device including a touch panel or an image display device such as a plasma display.

  However, objects to which the polarizing plate according to one embodiment of the present invention can be applied are not limited to these.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

<Manufacture of polyester resin film>
(Polyester resin film P1)
[Preparation of polyester resin (A)]
The esterification reaction vessel was heated, and at 200 ° C., 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were added, and while heating and stirring, 0.017 parts by mass of antimony trioxide as a catalyst was added. And 0.064 parts by mass of magnesium acetate tetrahydrate and 0.16 parts by mass of triethylamine. The pressure esterification reaction was performed under the conditions of a gauge pressure of 0.34 MPa and a temperature of 240 ° C. Next, the esterification reaction vessel was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. Further, the temperature was raised to 260 ° C. in 15 minutes, and 0.012 parts by mass of trimethyl phosphate was added. Then, after 15 minutes, a dispersion treatment was carried out with a high-pressure disperser. After 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction vessel, and a polycondensation reaction was carried out at 280 ° C. under reduced pressure. After the completion of the polycondensation reaction, a filtration treatment is carried out with a NASLON (registered trademark) filter NF-05S manufactured by Nippon Seisen Co., Ltd., extruded into a strand shape from a nozzle, and a filtration treatment (pore diameter: 1 μm or less) is performed in advance, followed by cooling. The resin was cooled and solidified using water, and the resin was cut into pellets. The obtained polyester resin (polyethylene terephthalate resin) (A) did not substantially contain inert particles and internally precipitated particles (hereinafter, also referred to as PET (A)).

[Preparation of coating solution for easy adhesion layer]
A transesterification reaction and a polycondensation reaction are carried out by a conventional method, and as a dicarboxylic acid component (based on the whole dicarboxylic acid component) 46 mol% of terephthalic acid, 46 mol% of isophthalic acid and 8 mol% of sodium 5-sulfonatoisophthalate Was used to prepare a water-dispersible sulfonic acid metal base-containing copolymerized polyester resin containing 50 mol% of ethylene glycol and 50 mol% of neopentyl glycol as a diol component (based on the whole diol component).

  Next, 51.4 parts by mass of water, 38 parts by mass of isopropyl alcohol, 5 parts by mass of n-butyl cellosolve, and 0.06 parts by mass of a nonionic surfactant were mixed, heated and stirred, and reached 77 ° C. After adding 5 parts by mass of the water-dispersible sulfonic acid metal base-containing copolymerized polyester resin and continuing to heat and stir until the resin is no longer solidified, the resin aqueous dispersion is cooled to room temperature and the solids concentration is 5. A uniform water-dispersible copolymerized polyester resin liquid of 0% by mass was obtained. Further, 3 parts by mass of aggregated silica particles (manufactured by Fuji Silysia Chemical Ltd., Sylysia 310) were dispersed in 50 parts by mass of water. To 99.5 parts by mass of the above-mentioned water-dispersible copolymerized polyester resin solution, 0.54 parts by mass of an aqueous dispersion of Sylysia 310 was added, and 20 parts by mass of water was added with stirring to prepare an easily adhesive layer coating solution.

[Production of polyester resin film]
The above-prepared polyester resin (A) is dried in a conventional manner, supplied to an extruder, melted at 285 ° C., and the polymer is filtered through a stainless sintered filter medium (nominal filtration accuracy: 10 μm, particles cut by 95%). After being extruded into a sheet from a die, it was wound around a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method, and cooled and solidified to produce an unstretched polyester resin film (PET film).

Then, after applying the coating liquid for easy-adhesion layer prepared above on both sides of the unstretched PET film by a reverse roll method so that the coating amount after drying is 0.08 g / m ² , the coating liquid is heated at 80 ° C. for 20 seconds. Dried.

  The unstretched film on which the easy-adhesion layer was formed was guided to a tenter stretching machine, and stretched 1.5 times in the width direction in a heating zone at a temperature of 125 ° C. while holding the ends of the film with clips. Next, while maintaining the width stretched in the width direction, the film is treated at a temperature of 225 ° C. for 30 seconds, and further subjected to a relaxation treatment of 3% in the width direction, so that the PET film alone has a thickness of 70 μm. A uniaxially oriented PET film having a thickness of each easily adhesive layer of 1 μm or less was produced. This film was used as a polyester resin film P1.

  In an environment of 23 ° C. and 55% RH of the polyester resin film P1, the retardation Ro (590) in the in-plane direction with respect to light having a wavelength of 590 nm is measured using an automatic birefringence meter AxoScan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). ) Was Ro = 790 nm.

(Polyester resin film P2)
In the production of the polyester resin film P1, the uniaxial uniaxial film was prepared in the same manner except that the extrusion conditions in the production of the unstretched polyester resin film (PET film) were changed so that the finally obtained film thickness was 25 μm for the PET film alone. An oriented PET film was manufactured. This film was used as a polyester resin film P2. Here, the thickness of each easily adhesive layer was 1 μm or less.

  In an environment of 23 ° C. and 55% RH of the polyester resin film P2, the retardation Ro (590) in the in-plane direction with respect to light having a wavelength of 590 nm is measured using an automatic birefringence meter AxoScan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). ) Was Ro = 290 nm.

(Polyester resin film P3)
[Preparation of polyester resin (B)]
When the temperature of the esterification reactor was raised to 200 ° C., 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were charged, and while stirring, 0.017 parts by mass of antimony trioxide was used as a catalyst. 0.064 parts by mass of magnesium acetate tetrahydrate and 0.16 parts by mass of triethylamine were charged. Next, the temperature was increased under pressure to perform a pressure esterification reaction under the conditions of a gauge pressure of 0.34 MPa and 240 ° C. Then, the esterification reactor was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. Further, the temperature was raised to 260 ° C. over 15 minutes, and 0.012 parts by mass of trimethyl phosphate was added. Next, after 15 minutes, a dispersion treatment was performed with a high-pressure disperser. After 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reactor, and a polycondensation reaction was performed at 280 ° C. under reduced pressure. After completion of the polycondensation reaction, the mixture is filtered through a NASLON filter having a 95% cut diameter of 5 μm, extruded into a strand from a nozzle, and cooled and solidified using cooling water that has been previously filtered (pore diameter: 1 μm or less). The resin was cut into pellets. The obtained polyester resin (polyethylene terephthalate resin) (B) did not substantially contain inert particles and internally precipitated particles (hereinafter, also referred to as PET (B)).

[Preparation of polyester resin (C)]
10 parts by mass of a dried ultraviolet absorber 2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazinone-4-one) and 90 parts by mass of particle-free PET (B) are mixed. Then, using a kneading extruder, a polyester resin (polyethylene terephthalate resin composition) (C) containing an ultraviolet absorber was obtained (hereinafter, also referred to as PET (C)).

[Production of polyester resin film]
A three-layer base film was produced. Specifically, as a raw material for the intermediate layer of the base film, 90 parts by mass of PET (B) resin pellets containing no particles and 10 parts by mass of PET (C) resin pellets containing an ultraviolet absorber were charged at 135 ° C. After drying under reduced pressure (1 Torr) for 6 hours, the mixture was supplied to an extruder 2 (for the intermediate layer II) and melted at 285 ° C. Further, PET (B) as a raw material for the outer layer of the base film was dried by a conventional method, supplied to the extruder 1 (for the outer layer I and the outer layer III), and melted at 285 ° C. The two types of polymers are respectively filtered with a stainless steel sintered body filter medium (nominal filtration accuracy: 10 μm, particles cut by 95%), laminated in a two-type three-layer merging block, extruded into a sheet from a die, and extruded. It was wound around a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method, and cooled and solidified to produce an unstretched film. At this time, the discharge amount of each extruder was adjusted such that the ratio of the thicknesses of the I layer, the II layer, and the III layer was 10:80:10.

Then, the unstretched PET film is prepared by the reverse roll method in the same manner as in the preparation of the coating solution for the easily adhesive layer in the preparation of the polyester resin film P1 so that the coating amount after drying on both surfaces of the unstretched PET film is 0.08 g / m ^2. After applying the easy-adhesion coating solution thus obtained, it was dried at 80 ° C. for 20 seconds.

  The unstretched film having the coating layer formed thereon was guided to a tenter stretching machine, and then guided to a hot air zone at a temperature of 125 ° C. while being gripped with clips, and stretched 4.0 times in the width direction. Subsequently, while maintaining the width stretched in the width direction, the film is treated at a temperature of 225 ° C. for 30 seconds, and further subjected to a relaxation treatment of 3% in the width direction, so that the film thickness of the PET film alone is 70 μm, A uniaxially oriented PET film having a thickness of each easily adhesive layer of 1 μm or less was produced. This film was used as a polyester resin film P3.

<Formation of hard coat layer>
(Preparation of Hard Coat Layer Coating Solution HC1)
50 parts by mass of a 20% by mass antimony-doped tin oxide modified alcohol dispersion (manufactured by Nikki Shokubai Kasei Co., Ltd., ELCOM NY-1019ATV), 1 part by mass of an ultraviolet absorber (Tinvin (registered trademark) 1130, manufactured by BASF Japan Ltd.), urethane 100 parts by mass of acrylate (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., UV-7600B), 3.8 parts by mass of photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd., Irgacure (registered trademark) 819) and 75 parts by mass of methyl alcohol (methanol) The parts were stirred and mixed to obtain a hard coat layer coating liquid HC1.

(Preparation of Hard Coat Layer Coating Solutions HC2-7)
In the preparation of the hard coat layer coating solution HC1, the hard coat layer coating solution HC2 was prepared in the same manner except that the presence or absence of the ultraviolet absorber, the type of the ultraviolet absorber or the amount of the ultraviolet absorber added was changed as shown in Table 1 below. 7 was prepared.

The details of each UV absorber contained in each hard coat layer described in Table 1 below are shown below;
-"Ti1130": Tinuvin (registered trademark) 1130, manufactured by BASF Japan KK, methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate / polyethylene glycol. 300 reaction products;
-"Ti928": Tinuvin (registered trademark) 928, 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4-1,1, manufactured by BASF Japan Ltd. 3,3-tetramethylbutyl) phenol;
"UVA5080": manufactured by Shin-Nakamura Chemical Co., Ltd., vanaresin UVA-5080, methacrylic acid ester copolymer having a partial structure including a methyl methacrylate-benzotriazole structure in a side chain, solid content concentration: 41% by mass;
"JF-80": JF-80, 2- (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) benzotriazole, manufactured by Johoku Chemical Co., Ltd.

(Formation of hard coat layer)
For each combination of the polyester resin film and the hard coat layer coating liquid shown in Table 1 below, after drying each hard coat layer coating liquid obtained above on each polyester resin film obtained above by slit reverse coating, Was applied so that the thickness of the film became the value shown in Table 1 below to form a coating film. After the obtained coating film is dried at 80 ° C. for 1 minute, the coating film is cured by irradiating ultraviolet rays with an ultraviolet irradiation amount of 300 mJ / cm ² to obtain each hard coat coating solution on each polyester resin film. The hard coat layer thus formed was formed. Thus, polyester resin films with each hard coat layer were produced.

<Manufacture of cycloolefin resin film and acrylic resin film>
(Cycloolefin resin film C1)
[Preparation of fine particle dispersion]
11.3 parts by mass of fine particles (Aerosil (registered trademark) R812, manufactured by Nippon Aerosil Co., Ltd.) and 84 parts by mass of ethanol were stirred and mixed with a dissolver for 50 minutes, and then dispersed with Mentongorin.

  5 parts by mass of the fine particle dispersion was slowly added to sufficiently stirred methylene chloride (100 parts by mass) in the dissolution tank. Further, dispersion was performed with an attritor so that the particle size of the secondary particles became a predetermined size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a liquid containing fine particles.

[Preparation of main dope]
A main dope having the following composition was prepared. First, dichloromethane and ethanol were added to a pressure dissolution tank. The following cycloolefin resin (cycloolefin polymer), an ultraviolet absorber, and a fine particle addition liquid were charged into a pressure dissolution tank containing a mixed solution of dichloromethane and ethanol while stirring. This was heated and completely dissolved with stirring, and this was filtered with Azumi Filter Paper No. The mixture was filtered using 244 to prepare a main dope.

100 parts by mass of cycloolefin resin (ARTON (registered trademark) F4520, manufactured by JSR Corporation)
200 parts by mass of dichloromethane,
10 parts by weight of ethanol,
5 parts by mass of an ultraviolet absorber (Tinuvin (registered trademark) 477, manufactured by BASF Japan Ltd.)
3 parts by mass of the fine particle additive liquid prepared above.

  ARTON (registered trademark) F4520 is a polymer having a structural unit having the following structure.

[Production of cycloolefin resin film]
Next, using an endless belt casting apparatus, the dope was uniformly cast on a stainless steel belt support at a temperature of 31 ° C. and a width of 1800 mm. The temperature of the stainless steel belt was controlled at 28 ° C. On a stainless steel belt support, the solvent was evaporated until the amount of the residual solvent in the cast dope became 30% by mass. Next, the film-like material (web) was peeled from the stainless belt support at a peeling tension of 128 N / m. The peeled web was stretched 1.15 times in the width direction at 160 ° C. The residual solvent in the web at the start of stretching was 5% by mass. Subsequently, the drying of the web was terminated while the drying zone was conveyed by a number of rollers, and the end of the web sandwiched between tenter clips was slit with a laser cutter. Thereafter, the web after drying was wound up to have a thickness of 20 μm. A cycloolefin resin film C1 was produced.

(Cycloolefin resin film C2-5, 9 and 10)
In the production of the cycloolefin resin film C1, cycloolefin resin films C2 to 5, 9 and 10 were prepared in the same manner except that the presence or absence of the ultraviolet absorber, the type of the ultraviolet absorber, and the thickness of the film were changed as shown in Table 1 below. Was manufactured.

  Here, in the production of the cycloolefin resin film C9, the thickness of the film was changed by changing the casting conditions so that the desired thickness after winding was 60 μm.

The details of each UV absorber contained in each cycloolefin resin film described in Table 1 are shown below;
-"Ti477": Tinuvin (registered trademark) 477, manufactured by BASF Japan Ltd., an ultraviolet absorber represented by the above chemical formula 18);
-"3049": Uvinul (registered trademark) 3049, 2,2-dihydroxy-4,4-dimethoxybenzophenone, manufactured by BASF;
-"Ti928": Tinuvin (registered trademark) 928, 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4-1,1, manufactured by BASF Japan Ltd. 3,3-tetramethylbutyl) phenol;
-JF-80: JF-80, 2- (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) benzotriazole, manufactured by Johoku Chemical Co., Ltd .;
-"Chemical formula 17": an ultraviolet absorber represented by the following chemical formula 17

(Cycloolefin resin film C6)
In the production of the cycloolefin resin film C1, after peeling the film-like material (web), the peeled film raw material is described in paragraphs 0110 to 0124 of JP-A-2016-212146 under conditions of 160 to 190 ° C. According to the oblique stretching method, the stretching was performed obliquely in a direction of 45 degrees with respect to the longitudinal direction using a tenter shown in FIG. At this time, the casting conditions were changed and the stretching ratio was determined so that the thickness of the film formed after the stretching conditions after winding was 20 μm. Otherwise, in the same manner as in the production of the cycloolefin resin film C1, a cycloolefin resin film C6 having a thickness of 20 μm was produced.

  For the cycloolefin resin film C6, the in-plane retardation Ro with respect to light having a wavelength of 550 nm under an environment of 23 ° C. and 55% RH was measured using an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). As a result, the retardation Ro (550) in the in-plane direction was 90 to 120 nm, and the Rth (550) was 60 to 90 nm.

(Cycloolefin resin film C7)
In the production of the cycloolefin resin film C1, the stretching ratio at 160 ° C. was changed to 1.20 times, and the flow rate was adjusted so that the film formed under the stretching conditions had a thickness of 20 μm after winding. A cycloolefin resin film C7 was produced in the same manner except that the rolling conditions were changed.

  About the cycloolefin resin film C7, the average refractive index was measured by Abbe's refractive index system, and Ro and Rth at 590 nm were measured by KOBRA-21DH and Oji Scientific Instruments. Ro (590) = 30 to 60 nm, Rth (590) = 100 to 140 nm.

(Cycloolefin resin film C8)
[Preparation of cycloolefin polymer]
In an ethylene atmosphere, toluene and phenylnorbornene were charged into a 1.6 L autoclave so that the norbornene concentration was 20 mol / L and the total liquid volume was 640 mL. Then, 5.88 mmol of methylaluminoxane (manufactured by Albemarle, MAO 20% toluene solution) based on Al and 1.5 μmol of methylene (cyclopentadienyl) (tetramethylcyclopentadienyl) zirconium dichloride were added. Subsequently, the reaction was carried out at 80 ° C. for 60 minutes while introducing ethylene to keep the pressure at 0.2 MPa. After the completion of the reaction, ethylene was depressurized while allowing to cool, and the inside of the system was replaced with nitrogen. Thereafter, 3.0 g of silica (Grade: G-3 particle size: 50 μm, manufactured by Fuji Silysia Chemical Ltd.) whose amount of adsorbed water was adjusted to 10% by mass was added and reacted for 1 hour. Then, the obtained reaction solution is put into a pressure filter (Advantech Toyo Co., Ltd., model KST-90-UH) in which filter paper (5C, 90 mm) and Celite (Wako Pure Chemical Industries, Ltd.) are set, and nitrogen is added. The polymerization solution was recovered by pressure filtration. Further, the polymerization liquid was dropped little by little into 5 times the volume of acetone to precipitate a product, thereby obtaining a cycloolefin polymer (cycloolefin resin). The weight average molecular weight of C1 was 142,000, and the glass transition temperature was 140 ° C.

[Production of cycloolefin resin film]
The cycloolefin polymer prepared above was dried at 70 ° C. for 2 hours using a hot air dryer through which air was circulated to remove water, and then 100 parts by mass of the cycloolefin polymer was exposed to an ultraviolet absorber (Tinuvin ( (Registered trademark) 477, manufactured by BASF Japan Ltd.). Thereafter, the mixture was subjected to molding conditions at a molten resin temperature of 240 ° C. and a T-die temperature of 240 ° C. using a T-die film melt extrusion molding machine (T-die width: 500 mm) having a resin melt kneader equipped with a screw of 65 mmφ. And extruded to produce a cycloolefin resin film C8 having a thickness of 20 μm.

(Acrylic resin film A1)
[Preparation of dope]
A dope containing an acrylic resin ((meth) acrylic polymer) was prepared according to the following method. The following additives were sufficiently dissolved with stirring and heating to prepare a dope. The solid content concentration of the dope was 21% by mass.

100 parts by mass of an acrylic resin (Delpet (registered trademark) 80N manufactured by Asahi Kasei Chemicals Corporation)
5 parts by mass of an ultraviolet absorber (Tinuvin (registered trademark) 477, manufactured by BASF Japan Ltd.)
395 parts by mass of an organic solvent (methylene chloride: methanol: butanol = 79: 20: 1 (mass ratio)).

  Delpet (registered trademark) 80N is an MMA polymer having Mw = 100,000 and Tg = 114 ° C.

[Formation of acrylic resin film]
An acrylic resin film A1 was produced according to the following procedure using a casting facility having an endless belt as a casting support. First, the prepared dope was supplied to a casting die, and a casting film composed of a single layer of an acrylic resin layer was supplied onto an endless belt which was a metal support for casting. The supply amount of the dope was set so that the thickness after the final drying was 20 μm. Next, the dope supplied on the endless belt was dried by a drying air at 40 ° C. to form a film (web), and then separated from the endless belt. Next, both ends of the web were fixed with pins, and the web was dried with a drying air at 105 ° C. for 5 minutes while maintaining the same interval. After removing the pins, the web was further dried at 130 ° C. At this time, the amount of residual solvent was adjusted to 5% by mass by appropriately adjusting the drying time. Subsequently, the web was slit to a width of 1 m, and thereafter, tenter stretching was performed in a zone stretching at a stretching temperature of 120 ° C. at a magnification of 1.5 times in the width direction (TD direction) and 2.0 times in the transport direction (MD direction). To dry the web at a drying temperature of 135 ° C. After the tenter stretching, the web was subjected to a relaxation treatment at 130 ° C. for 5 minutes, and then the drying of the web was completed while conveying the drying zone at 120 ° C. and 140 ° C. by a number of rolls. Then, the dried web is slit to a width of 1.0 m, a knurling process of 10 mm in width and 5 μm in height is performed on both ends of the film, and then wound around a core to produce an acrylic resin film A1 subjected to a stretching treatment. did.

<Preparation of polarizing plate>
[Manufacture of polarizer]
A long polyvinyl alcohol film (Kuraray Co., Ltd. product name: Kuraray Vinylon PE3000) having a degree of polymerization of 2,400, a degree of saponification of 99.9 mol%, a thickness of 60 μm, and a width of 3,300 mm was used as a raw film as follows. To produce a polarizing film (polarizer). Stretching was performed with a difference in peripheral speed between the drive nip rolls before and after the treatment tank.

  First, the film was sufficiently swelled by immersing it in a swelling tank containing pure water at 37 ° C. for 80 seconds while maintaining the tension state in the transport direction (flow direction) so that the raw film was not loosened. The roll speed ratio between the inlet and the outlet of the swelling tank accompanying swelling was 1.2. After draining with a nip roll provided at the outlet of the swelling tank, it was immersed in a water immersion tank containing pure water at 30 ° C. for 160 seconds. The stretching ratio in the transport direction of the film in the water immersion tank was 1.04 times. Next, the film was uniaxially stretched at a draw ratio of about 1.6 times while immersing the film in a dyeing tank containing an aqueous solution of iodine / potassium iodide / water having a weight ratio of 0.04 / 1.5 / 100. . Thereafter, the first boric acid was immersed in a first boric acid bath containing an aqueous solution of potassium iodide / boric acid / water at a weight ratio of 12 / 3.6 / 100 at a temperature of 56.5 ° C. for 130 seconds. While performing the treatment, uniaxial stretching was performed until the cumulative stretching ratio from the raw material became 5.3 times. Further, a second boric acid treatment is performed by immersing the resultant in a second boric acid tank containing an aqueous solution of potassium iodide / boric acid / water at a weight ratio of 12 / 1.5 / 100 at a temperature of 30 ° C. for 60 seconds. Was. Subsequently, after being immersed in a washing tank containing 10 ° C. pure water for about 16 seconds for washing, they are sequentially passed through a drying furnace at about 60 ° C. and a drying furnace at about 85 ° C., and the total residence time in the drying furnaces is calculated. Drying was performed for 160 seconds. Thus, a 12 μm-thick polarizer having iodine adsorbed and oriented was obtained.

[Manufacture of polarizing plate]
As the combinations shown in Table 1 below, each of the above-obtained cycloolefin resin films or acrylic resin films and each of the above-obtained polyester resin films with a hard coat layer were prepared. Next, one surface of each of the cycloolefin resin film and the acrylic resin film, and a corona treatment on the surface opposite to the surface on which the hard coat layer of the obtained polyester resin film with each hard coat layer was formed, The films were bonded so that the corona-treated surfaces of the films were in contact with the polarizers. At this time, a 3% by mass aqueous solution of polyvinyl alcohol (PVA-117H manufactured by Kuraray Co., Ltd.) was used as the adhesive. In addition, upon lamination, lamination was performed such that the long direction of the polyester resin film with the hard coat layer, the cycloolefin resin film or the acrylic resin film, and the long direction of the polarizer coincided with each other. The laminated film was dried with hot air at 60 ° C. for 5 minutes to obtain each polarizing plate.

  Here, the slow axis of the polyester resin films P1 to P3 was a direction perpendicular to the longitudinal direction of the film (coincident with the MD direction and the transport direction) (coincident with the TD direction and the width direction). The slow axes of the cycloolefin resin films C1 to C5, C7, C9 and C10 were perpendicular to the longitudinal direction of the film. The slow axis of the cycloolefin resin film C6 was in a direction at 45 ° to the longitudinal direction of the film. The cycloolefin resin film C8 did not have a clear slow axis in the film plane. The slow axis of the acrylic resin film A1 was parallel to the longitudinal direction of the film. The direction of the absorption axis of the polarizer was parallel to the lengthwise direction of the polarizer.

  The molecular weights shown in Table 1 below are values calculated from the sum of atomic weights of ultraviolet absorbers other than the polymer type ultraviolet absorber. Here, since Tinuvin (registered trademark) 1130 manufactured by BASF Japan Ltd. is a mixture, the average value obtained from the molecular weight of each component and the content ratio of each component is described. In addition, as for the molecular weight of the polymer type ultraviolet absorber, a weight average molecular weight (Mw) measured according to the following method is described.

<Weight average molecular weight measurement conditions>
The weight average molecular weight was measured by gel permeation chromatography (GPC). The measurement conditions are as follows.

Solvent tetrahydrofuran,
Equipment name TOSOH HLC-8220GPC,
A column TOSOH TSKgel Super HZM-H (4.6 mm × 15 cm) was used by connecting three columns,
Column temperature 25 ° C,
Sample concentration 0.1% by mass,
Flow rate 0.35ml / min,
Calibration curve TOSOH standard polystyrene manufactured by TOSOH A calibration curve with 7 samples from Mw = 2800000 to 1050 was used.

<Evaluation of polarizing plate>
(Evaluation of irregular punchability)
An adhesive layer and a release film were laminated on one side of each polarizing plate obtained above. Next, the obtained polarizing plate with an adhesive was cut out by punching it out with a blade having the shape of a vehicle-mounted meter shown in FIG. In FIG. 1, the radius of two relatively small circles inside the figure is 60 mm, and the radius of one relatively large circle is 70 mm. The concave curve at the top of the on-vehicle meter is along the outer circumference of a perfect circle having a radius of 60 mm, which is assumed to be in contact with two circles inside the figure.

  Thereafter, the release film was peeled off from the polarizing plate cut and cut by the odd-shaped punch, and the adhesive side was bonded to a glass substrate for a liquid crystal cell manufactured by Corning. Ten such samples were prepared for each polarizing plate. In this state, first, whether or not the polarizer was broken was checked with an optical microscope, and the number of cracked samples was counted. Based on the following evaluation criteria, the irregular punching property was evaluated from the number of cracked polarizing plates. As a result of the evaluation, it was judged that there was no practical problem if the evaluation was not less than Δ.

◎: Number of cracked sheets 0,
：: 1 to 2 cracked sheets,
Δ: Number of cracks 3-5,
×: Number of cracks 6 or more.

(Evaluation of adhesion after heat resistance test)
Each of the polarizing plates obtained above was stored in a thermostat at 90 ° C. for 100 hours, and then left under an environment of 23 ° C. and 55% RH for 24 hours. Next, when the adhesive surface between the polarizer of the polarizing plate and the cycloolefin resin film or the acrylic resin film, and the adhesive surface between the polarizer and the polyester resin film of the polarizing plate were peeled by hand, material destruction in each film. The presence or absence of occurrence and the degree of peeling were visually observed, and the adhesion was evaluated according to the following evaluation criteria. In this evaluation, when the adhesive surface was peeled off by hand, peeling did not occur when the adhesive force was strong, and peeling occurred without destruction of the material at the interface between the film and the polarizer when the adhesive force was weak. If the adhesive strength is intermediate between these, material destruction occurs at the interface between the film and the polarizer. As a result of the evaluation, it was judged that there was no practical problem if the evaluation was not less than Δ.

A: Cycloolefin resin film or acrylic resin film and polyester resin film are not peeled off;
：: Regarding the cycloolefin resin film or the acrylic resin film, and the polyester resin film, there is no problem in the adhesive strength between the film and the polarizer.
Attempts to remove the film fall under any of (i) and (ii) below:
(I) one of these films does not peel off, and material (substrate) destruction occurs in at least half of the other film or at least one end of the polarizer;
(Ii) material (substrate) failure occurs in at least half of at least one end of both of these films or polarizers;
Δ: Cycloolefin resin film or acrylic resin film, and polyester resin film, both, there is no problem in the adhesive strength between the film and the polarizer,
When the film is to be peeled off, one of these films falls under any one of the following (iii) to (v), and the other film or the polarizer has a portion not more than half of at least one end thereof. Material (substrate) failure occurs:
(Iii) does not peel,
(Iv) material (substrate) breakage occurs in at least half of at least one end of the film or the polarizer;
(V) material (substrate) destruction occurs in less than half of at least one end of the film or polarizer;
×: about cycloolefin resin film or acrylic resin film, and polyester resin film, the adhesive strength between at least one film and the polarizer is insufficient,
At least one of the cycloolefin resin film, the acrylic resin film, and the polyester resin film is peeled off without causing material destruction at a part of the interface between the film and the polarizer.

(Evaluation of discoloration of polarizer)
For each of the polarizing plates obtained above, the parallel light transmittance (H0) and the orthogonal light transmittance (H90) of the untreated sample subjected to forced deterioration were measured, and the degree of polarization P0 (%) was calculated according to the following equation. Thereafter, the polarizing plate was subjected to a forced deterioration treatment under the condition without a UV cut filter for 500 hours with a sunshine weather meter, and then the parallel light transmittance (H0 ') and the orthogonal light transmittance (H90') after the forced deterioration treatment were again applied. Was measured, and the degree of polarization P500 (%) was calculated according to the following equation. From these results, the degree of polarization change (%) was calculated according to the following equation. Here, when the polarization degree change (%) is less than 10%, it is assumed that the polarizing plate has a good ultraviolet ray cutting ability.

[Calculation of polarization degrees P0 and P500 and polarization degree change amount]
Degree of polarization P0 (%) = [(H0−H90) / (H0 + H90)] 1/2 × 100
Polarization degree P500 (%) = [(H0′−H90 ′) / (H0 ′ + H90 ′)] 1/2 × 100
Polarization change (%) = P0-P500
As the evaluation result of the fading of the polarizer, the polarizer No. The polarizing plate Nos. 1 to 19, 21 and 22 had a polarization degree change of less than 10%. 20 and no. No. 23 confirmed that the degree of polarization change was 25% or more. In addition, the polarizing plate No. 1 to 19, 21 and 22, the polarizer Nos. 13, the polarizing plate No. It was confirmed that 1 to 12, 14 to 19, 21 and 22 had smaller amounts of change in the degree of polarization.

(Light leakage evaluation)
Using each of the polarizing plates obtained above, a liquid crystal display device was manufactured according to the following method. First, IPS mode and VA mode liquid crystal cells each having a glass substrate having a total thickness of 0.1 mm and a liquid crystal layer disposed therebetween were prepared as liquid crystal cells. Then, each polarizing plate, so that the cycloolefin resin film or acrylic resin film side of the polarizing plate is disposed on the liquid crystal cell side, the absorption axis of the polarizer of the polarizing plate on the viewing side via an adhesive, and the backlight side The liquid crystal cell was adhered to both sides of the liquid crystal cell such that the absorption axes of the polarizers of the polarizing plate were orthogonal to each other, thereby obtaining a VA liquid crystal display device and an IPS liquid crystal display device having each polarizing plate. Each of the liquid crystal display devices thus obtained was stored in an environment of 60 ° C. and 90% RH for 500 hours, and then left in an environment of 23 ° C. and 55% RH for 24 hours. Then, in a dark room, the appearance of display unevenness due to light leakage from four corners of the screen during black display was visually observed.

  As a result of the light leakage evaluation, the polarizing plate No. No light leakage was observed in polarizing plates Nos. 1 to 16. Light leakage was confirmed in 17 to 23.

  Table 2 below shows the results of the evaluation of the irregular punching property and the evaluation of the adhesiveness after the heat resistance test.

(Evaluation result of polarizing plate)
From the results in Table 2, the polarizing plate No. 1 according to the present invention was obtained. It was confirmed that Nos. 1 to 16 were excellent in both the irregular punching property and the adhesive property after the heat test.

  On the other hand, a polarizing plate No. which does not belong to the technical scope of the present invention. 17 to 23, it was confirmed that both the irregular punching property and the adhesiveness after the heat test were insufficient.

  Also, from the results of the evaluation of the fading of the polarizer, the polarizing plate No. 1 according to the present invention was obtained. Nos. 1 to 16 were confirmed to have excellent ultraviolet ray cutting ability. On the other hand, the polarizing plate no. 20 and no. In No. 23, the amount of change in the degree of polarization was large. This is because the polarizing plate No. 20 and no. In No. 23, since no ultraviolet absorber was contained in the hard coat layer and the polyester resin film, it was speculated that ultraviolet light was transmitted from this surface to the polarizer and the polarizer was deteriorated.

  Further, the liquid crystal display device manufactured by the light leakage evaluation was left for a certain period under ultraviolet irradiation instead of being stored in an environment of 60 ° C. and 90% RH for 500 hours, and similarly observed in a dark room. Polarizing plate No. 20 and polarizing plate No. Light leakage was confirmed only in the liquid crystal display device using No. 23 (VA liquid crystal display device, IPS liquid crystal display device). At this time, in particular, the polarizing plate No. It was confirmed that the degree of light leakage in the liquid crystal display device using No. 23 was large. This is because the polarizing plate No. 20 and no. In No. 23, since no ultraviolet absorber was contained in the hard coat layer and the polyester resin film, it was speculated that ultraviolet light was transmitted from this surface to the polarizer and the polarizer was deteriorated. In addition, the polarizing plate No. In No. 23, it is speculated that since the cycloolefin resin film also contained no ultraviolet absorber, ultraviolet light was further transmitted to the liquid crystal cell, and the liquid crystal cell was deteriorated in addition to the polarizer.

  This application is based on Japanese Patent Application No. 2017-050563 filed on March 15, 2017, the disclosure of which is incorporated by reference in its entirety.

Reference Signs List 1 polarizing plate 2 hard coat layer 3 polyester resin film 4 easy-adhesion layer 5 polarizer 6 cycloolefin resin film

Claims (7)

A hard coat layer, a polyester resin film, a polarizer, a cycloolefin resin film containing a cycloolefin polymer or an acrylic resin film containing a (meth) acrylic polymer has a laminated structure in which the acrylic resin film is laminated in this order,
The hard coat layer, and the cycloolefin resin film or the acrylic resin film contains an ultraviolet absorber,
A polarizing plate, wherein the polyester resin film does not substantially contain an ultraviolet absorber.   The ultraviolet absorber contained in the cycloolefin resin film or the acrylic resin film is a compound having one benzotriazole skeleton in a molecule or a compound having one triazine skeleton in a molecule. Polarizer.   The polarizing plate according to claim 1, wherein the ultraviolet absorber contained in the hard coat layer has a molecular weight of 700 or more. 4. The hard coat layer contains an ionizing radiation-type curable compound,
For the content (parts by mass) of the ultraviolet absorber with respect to 100 parts by mass of the cycloolefin polymer or the (meth) acrylic polymer contained in the cycloolefin resin film or the acrylic resin film,
The ratio of the content (parts by mass) of the ultraviolet absorbent to 100 parts by mass of the ionizing radiation-curable compound contained in the hard coat layer is 0.05 to 1.
The polarizing plate according to claim 1.   5. The ratio of the thickness (μm) of the polyester resin film to the thickness (μm) of the cycloolefin resin film or the acrylic resin film is 0.1 to 5, 5. Polarizing plate.   The ratio of the thickness (μm) of the hard coat layer to the thickness (μm) of the cycloolefin resin film or the acrylic resin film is 0.002 to 1, according to any one of claims 1 to 5. Polarizing plate.   A display device comprising the polarizing plate according to claim 1.