JP7099440B2 - A polarizing plate and a display device equipped with the polarizing plate. - Google Patents

Description

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

Display devices are widely used in personal computers, monitors for mobile devices, and television applications. In recent years, especially in in-vehicle applications, there is a demand for display devices that emphasize design. For in-vehicle applications, a display having a free shape such as a shape having rounded corners, a shape having a complicated curved surface, or a shape having a hole in the center may be used instead of the conventional rectangular shape. Such a freely shaped display is called a deformed panel or a freeform display (FFD), and is considered to be used for a meter or the like of an automobile. An example of a deformed panel is a display having a shape that matches the curve of an analog meter, as shown in FIG. 1 to be described later.

The polarizing plate is generally made of a polarizing element produced by uniaxially stretching (usually 5 to 10 times) the surface of the polarizing element protective film on the side facing the polarizing element, which has been appropriately surface-treated, in an iodine solution. It is known that it is produced by adhering at least one surface to each other using an adhesive.

Display devices for in-vehicle use are required to have high durability, and high durability is also required as a polarizing plate. In recent years, PET (polyethylene terephthalate) film, cycloolefin resin film, acrylic resin film and the like have been used as substitutes for the conventional TAC film (triacetyl cellulose film) as the stator protective film from the viewpoint of improving water resistance. It has come to be.

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

Further, Japanese Patent Application Laid-Open No. 2016-107498 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. Has been done. According to the document, such a protective film may provide high UV protection, low colorability and scratch resistance sufficient to protect members such as stators. Here, the document discloses that the protective film using a polyester resin film as a base film is used as one of the polarizing element protective films in the polarizing plate. Further, it is disclosed that a stretched cyclic olefin film (cycloolefin resin film), which is a retardation plate (phase difference film), is used as the other substituent protective film.

However, although the polarizing plate disclosed in JP-A-2015-166875 or JP-A-2016-107498 has an ultraviolet ray blocking function and is excellent in water resistance, cracks in the cycloolefin resin film (cracking of the cycloolefin resin film when the polarizing plate is cut) ( The problem was that cracks, cracks, and hangnail at the edges) could occur. The polarizing plate for deformed panel use needs to be cut along the shape of the panel. At this time, in the polarizing plate disclosed in Japanese Patent Application Laid-Open No. 2015-166875 or Japanese Patent Application Laid-Open No. 2016-107498, a cycloolefin resin film is used. It has been a particular problem that cracks (cracks, cracks and hangnail at the edges) occur more frequently than when cutting a conventional rectangle.

Further, the polarizing plate disclosed in Japanese Patent Application Laid-Open No. 2015-166875 or Japanese Patent Application Laid-Open No. 2016-107498 has a problem that peeling may easily occur between the polarizing element protective film and the polarizing element. rice field. Polarizers for in-vehicle use are required to be durable in harsh environments, especially in high temperatures, but the polarizing plates disclosed in JP-A-2015-166875 or JP-A-2016-107498 are under high temperature. It has been a particular problem that the use of the polarizing element causes peeling between the polarizing element protective film and the polarizing element.

The present invention has been made in view of the above problems, and is used in a polarizing plate having an ultraviolet ray blocking function, which uses a polyester resin film and a cycloolefin resin film or an acrylic resin film as a substituent protective film. It is an object of the present invention to provide a means capable of reducing the failure at the time of punching out a deformed shape and improving the adhesiveness between the polarizing element protective film and the polarizing element after a lapse of time at a high temperature.

The above-mentioned problems of the present invention are solved by the following means.

It has a laminated structure in which a hard coat layer, a polyester resin film, a polarizing element, and a cycloolefin resin film or an acrylic resin film are laminated in this order.
The hard coat layer and the cycloolefin resin film or the acrylic resin film contain an ultraviolet absorber and contain an ultraviolet absorber.
The polyester resin film is a polarizing plate that does not substantially contain an ultraviolet absorber.

It is a schematic diagram which shows an example of the deformed panel to which the polarizing plate which concerns on one embodiment of this invention can be applied. It is a schematic cross-sectional view which shows the structure of the polarizing plate which concerns on one preferable embodiment of this invention.

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

Further, in the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.

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

Further, unless otherwise defined in the present specification, "copolymer" means block copolymer, random copolymer, graft copolymer or alternate copolymer, and "copolymer" means block copolymer. It means a coalescence, a random copolymer, a graft copolymer or an alternating copolymer.

<Polarizer>
The present invention has a laminated structure in which a hard coat layer, a polyester resin film, a polarizing element, and a cycloolefin resin film or an acrylic resin film are laminated in this order, and the hard coat layer and the cycloolefin resin film are laminated. Alternatively, the acrylic resin film relates to a polarizing plate, which contains an ultraviolet absorber and the polyester resin film substantially does not contain an ultraviolet absorber. According to the polarizing plate according to the present invention, in a polarizing plate having a UV-cutting function using a polyester resin film and a cycloolefin resin film or an acrylic resin film as a substituent protective film, a failure during deformation punching of the polarizing plate It is possible to improve the adhesiveness between the polarizing element protective film and the polarizing element after a lapse of time at a high temperature.

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 the TAC film conventionally used as a polarizing element protective film. From this, when the polyester resin film contains an ultraviolet absorber as in the polarizing plate according to JP-A-2015-166875, the glass transition temperature is further lowered and the film is softened. A polarizing plate containing such a polyester resin film tends to be easily deformed by the polarizing plate itself when the blade is pressed against the polarizing plate during cutting. Further, unlike the conventional punching with a rectangular shape, the force required for cutting is not constant in each direction in the irregular punching. At this time, in the polarizing plate containing such a polyester resin film, the in-plane of the polarizing plate at the time of deformed punching is caused by the ease of deformation of the polarizing plate and the difference in the force required for cutting in each direction due to the deformed punching. In a part of the above, a failure such as poor cutting, cracking of the polarizing element protective film, or peeling of the polarizing element protective film and the polarizing element will occur. In addition, due to the low glass transition temperature of the polyester resin film and softening, curling occurs in the polyester resin film over time at high temperatures, and this curling causes peeling between the polarizing element protection film and the polarizing element. It will occur.

In addition, the polarizing plate according to JP-A-2015-166875 or JP-A-2016-107498 maintains the curl balance of the entire polarizing plate because the polarizing element protective films made of different materials are arranged on both sides of the polarizing element. Will be difficult. Further, in the polarizing plate according to JP-A-2016-107498, it is necessary to add an ultraviolet absorber to the surface protective layer in order to realize the ultraviolet ray blocking function. At this time, the softening of the surface protective layer causes the entire polarizing plate to be softened. It becomes even more difficult to maintain the curl balance of. As a result, in the polarizing plate according to JP-A-2015-166875 or JP-A-2016-107498, fine curls are generated in different places in the polarizing plate surface. In such a polarizing plate, due to the generation of fine curls and the difference in the force required for cutting in each direction due to the deformation punching, a polarizing element protective film, particularly, is used in a part of the polarizing plate surface during the deformation punching. Cracks will occur in the cycloolefin resin film and the acrylic resin film.

On the other hand, since the polyester resin film used for the polarizing plate according to the present invention does not substantially contain an ultraviolet absorber, the glass transition temperature does not decrease and the film does not soften. Therefore, in the polarizing plate according to the present invention, deformation of the film during irregular punching is suppressed, and failure during irregular punching is reduced. Further, in the polarizing plate according to the present invention, the generation of curl of the polyester resin film over time at high temperature is suppressed, and the adhesiveness between the polarizing element protective film and the polarizing element after aging at high temperature is improved.

Further, the polarizing element protective film having no hard coat layer is usually arranged on the side of the two polarizing element protective films that is relatively close to the panel. Conventionally, the cycloolefin resin film or the acrylic resin film arranged on the side relatively close to the panel is special because it satisfies the optical characteristics (particularly, retardation, etc.) required for the polarizing element protection film and the retardation film. It was common that various additives were added and that resin modification was performed. From this, in the art, adding an ultraviolet absorber to a cycloolefin resin film or an acrylic resin film arranged relatively close to the panel may cause deterioration of the above optical properties and productivity. Therefore, no positive consideration has been made.

On the other hand, in the polarizing plate according to the present invention, an ultraviolet absorber is added to the hard coat layer in order to realize an ultraviolet ray blocking function, and a cycloolefin resin film is used as a film arranged relatively close 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 it is possible to suppress the generation of fine curls in different states depending on the location in the polarizing plate surface. Therefore, in the polarizing plate according to the present invention, cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are reduced in a part of the polarizing plate surface at the time of punching out the deformed shape.

Further, in the polarizing plate according to the present invention, the cycloolefin resin film or the acrylic resin film contains an ultraviolet absorber, so that the interaction between these films and the polarizing element is enhanced. Therefore, in the polarizing plate according to the present invention, even when the polarizing element protective film is deformed over time at a high temperature, peeling between these films and the polarizing element is suppressed, and these films are suppressed. The adhesiveness between the and the polarizing element is improved.

The above mechanism is based on speculation, 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 splitter 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 that 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 easy-adhesion layer 4 and the cycloolefin resin film 6 of the polyester resin film 3 to the polarizing element 5 is not shown.

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

(Polyester resin film)
The 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 represents 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, the excellent water resistance derived from the polyester may not be obtained. From the same viewpoint, the content of polyester is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and 99% by mass or more. Is particularly preferable (upper limit 100% by mass).

In the present specification, the "polyester resin film" refers to a film itself that can be formed from a polyester alone or a composition containing the polyester, and does not include another functional layer such as a hard coat layer.

[polyester]
Polyester (polyester resin), which is a raw material resin for a 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, and is, 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, diphenoxyetanedicarboxylic acid, diphenylsulfonic acid, anthracendicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydro Telephthalic 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, Examples thereof include pimelliic acid, azelaic acid, dimer acid, sebacic acid, suberic acid, dodecadicarboxylic acid, salts thereof 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, and is, for example, ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3-. Propylene diol, 1,4-butane diol, 1,5-pentane diol, 1,6-hexadiol, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone and the like can be mentioned. 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, one type thereof may be used alone, or two or more types thereof may be used in combination.

Specific examples of the polyester resin constituting the polyester resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene terephthalate, polybutylene terephthalate and the like, and polyethylene terephthalate (PET) or polyethylene terephthalate (PET) is preferable. It is polyethylene terephthalate (PEN), more preferably polyethylene terephthalate (PET). The polyester resin may contain other copolymerization components as needed, and the ratio of the copolymerization components is 3 mol%, where the total of the dicarboxylic acid component and the diol component is 100 mol% from the viewpoint of mechanical strength. The following is preferable, more preferably 2 mol% or less, still more preferably 1.5 mol% or less (lower limit 0 mol%). These resins have excellent transparency as well as excellent thermal and mechanical properties. In addition, 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 contains substantially no ultraviolet absorber. In the present specification, "substantially containing no ultraviolet absorber" means that the content of the ultraviolet absorber is 0.1% by mass or less with respect to the total mass of the polyester resin film. The term "polyester resin film" as used herein refers to a film itself that can be formed from a resin composition containing polyester, and does not include other functional layers such as a hard coat layer. When the content of the ultraviolet absorber in the polyester resin film is more than 0.1% by mass with respect to the total mass of the polyester resin film, the frequency of failure at the time of punching out the deformed shape of the polarizing plate increases, and the time-lapse at high temperature is increased. There is a risk that the adhesiveness between the later polarizing element protective film and the polarizing element will be insufficient. From this point of view, the content of the ultraviolet absorber in the polyester resin film is more preferably 0.05% by mass or less, and more preferably 0.01% by mass or less, based on the total mass of the polyester resin film. Is more preferable, and it is particularly preferable that it is not contained at all (0% by mass).

Examples of the ultraviolet absorber that can be contained in the polyester resin film in a very small amount include the hard coat layer described later, the ultraviolet absorber contained in the cycloolefin resin film and the acrylic resin film, and the like.

[optical properties]
The retardation Ro and Rth of the polyester resin film are defined by the following formulas, respectively;
Equation (I) Ro = (nx-ny) × d
Equation (II) Rth = {(nx + ny) /2-nz} × d
(However, nx represents the refractive index in the direction x at which the refractive index becomes maximum in the in-plane direction of the film, and 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 retardation Ro (590) in the in-plane direction with respect to light having a wavelength of 590 nm in the environment of 23 ° C. and 55% RH of the polyester resin film is not particularly limited, but the smaller it is, the more preferably 1000 nm or less. preferable. When the retardation Ro (590) in the in-plane direction is in 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. In addition, since the light interference itself caused by the retardation is reduced, it is possible to further reduce the rainbow unevenness. From the same viewpoint, the in-plane retardation Ro (590) of the polyester resin film is more preferably 800 nm or less, further preferably 350 nm or less, and particularly preferably 300 nm or less. 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 used. ) Is preferably 30 nm or more. The retardation Ro (590) in the in-plane direction 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 for light with a wavelength of 590 nm under the environment of 23 ° C. and 55% RH is an automatic birefringence index meter (Axo Scan Mueller Matrix Polarimeter) manufactured by Axometrics. ) Can be used for measurement.

[Thickness]
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. 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.

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

(Manufacturing method of polyester resin film)
The polyester resin film can be obtained according to a general manufacturing method. Specifically, the non-oriented polyester obtained by melting the polyester resin and extruding it into a sheet is stretched in the vertical direction (MD direction) using the speed difference of the roll at a temperature equal to or higher than the glass transition temperature, or tentered. Melt casting to produce a polyester resin film by stretching in the lateral direction (TD direction) used, or both stretching, and further performing heat treatment as necessary and relaxation treatment (relaxation treatment) as necessary. The law etc. can be mentioned. 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.

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

Controlling the retardation within a specific range can be performed by appropriately setting the draw ratio, the draw temperature, and the thickness of the film. For example, the larger the difference in stretching ratio between longitudinal stretching and transverse stretching, the lower the stretching temperature, and the thicker the film, the easier it is to obtain high retardation. On the contrary, the smaller the difference in stretching ratio between the longitudinal stretching and the transverse stretching, the higher the stretching temperature, and the thinner the film, the easier it is to obtain low retardation. Further, the higher the stretching temperature and the smaller the total stretching ratio, the easier it is to obtain a film having a low ratio (Ro / Rt) between the retardation value and the retardation value in the thickness direction. On the contrary, the lower the stretching temperature and the higher the total stretching ratio, the easier it is to obtain a film having a high ratio (Ro / Rt) of the retardation value and the retardation value in the thickness direction.

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

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

Further, in the uniaxial stretching and biaxial stretching treatments, after the transverse stretching, heat treatment or stretching treatment can be performed again in order to alleviate the distortion of the orientation spindle as typified by Boeing. ..

[Other functional layers]
The polarizing plate according to one embodiment of the present invention has a hard coat layer, which will be described later, as a functional layer on a surface of the polyester resin film opposite to the surface on the side opposite to the surface where the polarizing element is present, but other than the hard coat layer. It may further have other functional layers. 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 the polarizing plate and the polarizing element protective film can be appropriately selected. Other functional layers include, for example, an easy-adhesive layer, an anti-glare layer, an anti-reflection layer, a low-reflection layer, a low-reflection anti-glare layer, an anti-reflection anti-glare layer, an anti-static layer, a silicone layer, an adhesive layer, and an anti-fouling layer. , Fingerprint resistant layer, water repellent layer, blue cut layer and the like.

In the polarizing plate according to one embodiment of the present invention, when the hard coat layer and the other functional layer are provided on at least one surface side of the polyester resin film, it is preferable to provide the 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 alignment film. A known method can be adopted for adjusting the refractive index of the easy-adhesion layer, and for example, it can be easily adjusted by containing silica, titanium or zirconium, or other metal species in the binder resin. The coating liquid used for forming the easy-adhesion 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 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. Examples thereof include water-soluble or water-dispersible copolymerized polyester resin solution, acrylic resin solution, polyurethane resin solution and the like disclosed in Japanese Patent No. 3589233, Japanese Patent No. 3900191, Japanese Patent No. 4150982 and the like. Among these, a water-soluble or water-dispersible copolymerized polyester resin is preferable.

When the polyester resin film has an easy-adhesive layer on its surface, the polyester resin film having the easy-adhesive layer is dried by applying a coating liquid used for forming the easy-adhesive layer to the surface of the unstretched polyester resin film. It is preferable to form an easy-adhesion layer. Then, in the polyester resin film having the easy-adhesion layer, the unstretched polyester resin film is then subjected to the above-mentioned longitudinal stretching, lateral stretching, or both stretching, and heat treatment is performed as necessary, and relaxation treatment (relaxation treatment) is performed as necessary. Treatment) is more preferable.

The lower limit of the thickness of the easy-adhesive layer is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.1 μm or more from the viewpoint of functional expression of the easy-adhesive layer. The upper limit of the thickness of the easy-adhesive layer is not particularly limited, but is preferably 5 μm or less, and more preferably 1 μm or less from the viewpoint of thinning.

(Hard coat layer)
The 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 by irradiating with ionizing radiation. As the ionizing radiation, electromagnetic waves or charged particle beams having energy quantum capable of polymerizing or cross-linking molecules, for example, ultraviolet rays (UV) or electron beams (EB), and other X-rays and γ-rays are used. Electromagnetic waves such as, α rays, and charged particle beams such as ion rays 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 can be appropriately selected and used from known polymerizable monomers, polymerizable oligomers or prepolymers.

As the polymerizable monomer, a (meth) acrylate monomer having a radically polymerizable unsaturated group in the molecule is preferable, and a polyfunctional (meth) acrylate monomer is particularly 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 the molecule, and for example, diethylene glycol di (meth) acrylate and propylene glycol di (meth). ) Acrylate, Trimethylol Propanetri (meth) Acrylate, Trimethylol Propaneethyleneoxide Tri (meth) Acrylate, Dipentaerythritol Tetra (Meta) Acrylate, Dipentaerythritol Penta (Meta) Acrylate, Dipentaerythritol Hexa (Meta) Acrylate, etc. Is preferably mentioned. Further, the above (meth) acrylate may be one in which a part of the molecular skeleton is modified, and is modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol and 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, but 2 to 8 are selected from the viewpoint of improving the curability of the ionizing radiation curable resin composition and the scratch resistance of the surface protective layer. It is preferable, more preferably 2 to 6, still more preferably 3 to 6.

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

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, and is, for example, urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, polyfluoroalkyl (meth) acrylate, and silicone. Examples thereof include (meth) acrylate. Further, the above (meth) acrylate may be one in which a part of the molecular skeleton is modified, and is modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol and 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, but 2 to 8 are selected from the viewpoint of improving the curability of the ionizing radiation curable resin composition and the scratch resistance of the surface protective layer. It is preferable, more preferably 2 to 6.

The weight average molecular weight of the polyfunctional (meth) acrylate oligomer is preferably 1,000 to 20,000, more preferably 1,000 to 15,000, and 1,000 to 10,000. It is more preferably present, and particularly preferably 1,000 to 5,000. The weight average molecular weight is a value obtained by polystyrene conversion by gel permeation chromatography (GPC).

The content of the ionizing radiation curable compound is preferably 50 to 99.7% by mass, more preferably 60 to 98% by mass, still more preferably 70 to 93% by mass, based on the total mass of the ionizing radiation curable resin composition. 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 ionizing radiation curable resin composition. be.

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

As the ionizing radiation curable compound, a commercially available product may be used. 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 an additive such as a photopolymerization initiator or a photopolymerization accelerator.

The photopolymerization initiator is not particularly limited, and examples thereof include acetophenone, α-hydroxyalkylphenone, acylphosphine oxide, benzophenone, Michler ketone, benzoin, benzylmethyl ketal, benzoyl benzoate, α-acyl oxime ester, and thioxanthones. Be done. These can be used alone or in combination of two or more.

Among these, the photopolymerization initiator is preferably acylphosphine oxide, which is 2,4,6-trimethylbenzoyl-diphenyl-phosphinoxide or bis (2,4,6-trimethylbenzoyl) -phenylphosphinoxide. Is more preferable, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide is even more preferable.

As the ionizing radiation curable compound, a commercially available product may be used. 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, and particularly preferably 1 to 10 parts by mass with respect to 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 ionizing radiation curable compound in the cured product.

In addition, the photopolymerization accelerator has an effect of reducing polymerization damage due to air during curing and accelerating the curing rate. The photopolymerization accelerator is not particularly limited, and examples thereof include p-dimethylaminobenzoic acid isoamyl ester and p-dimethylaminobenzoic acid ethyl ester. 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 imparting an ultraviolet ray blocking 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 polarizing element protective film or a polarizing plate can be appropriately used.

The ultraviolet absorber is not particularly limited, and examples thereof include benzophenone-based compounds, benzotriazole-based compounds, triazine-based compounds, benzoxazine-based compounds, salicylic acid ester-based compounds, and cyanoacrylate-based compounds.

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 even more preferred.

The benzophenone 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 are independently hydrogen atom, cyano group, chlorine atom, fluorine atom, -CF ₃ group, -CO-G ³ group, E ³ SO- group or 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, and a cycloalkyl group having 5 to 12 carbon atoms. Represents the phenyl group or the phenylalkyl group in which the phenyl ring is substituted with an arylalkyl group having 7 to 15 carbon atoms, an aryl group, or 1 to 4 alkyl groups having 1 to 4 carbon atoms.

E ¹ and E ² are independently linear or branched alkyl groups having 1 to 24 carbon atoms; linear or branched alkenyl groups having 2 to 18 carbon atoms; carbon atoms. Cycloalkyl group number 5-12; arylalkyl group having 7 to 15 carbon atoms; aryl group; alkyl group having 1 to 4 carbon atoms, said aryl group or said arylalkyl substituted with 1 to 4 atoms. Groups; 1 or more -OH groups, -OCOE ¹¹ groups, -OE ⁴ groups, -NCO groups, -NH ₂ groups, -NHCOE ¹¹ groups, -NHE ⁴ groups, -N (E ⁴ ) ₂ The alkyl group having 1 to 24 carbon atoms or the alkenyl group having 2 to 18 carbon atoms substituted with a group, -COOH group or -COOE ⁵ groups; one or more -O- groups, -NH-group or -NE ⁴ -group interrupted and unsubstituted, or one or more, -OH group, -OE ⁴ group, -NH ₂ , -COOH group or -COOE ⁵ group Represents the alkyl group or the alkenyl group which can be substituted with. Here, the position of interruption by the —O— group, the —NH— group or the ^—NE4− group is not particularly limited, but is preferably the alkyl group, the alkenyl group, or the alkyl group in ^E5 .

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

^E5 is a linear or branched chain having 1 to 24 carbon atoms, which may be substituted with an unsubstituted or one or more -OH group, COOH group or -NH ₂ group. Represents an alkyl group.

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

E ³ has 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 5 to 12 carbon atoms. The aryl group substituted with one or two cycloalkyl groups, arylalkyl groups having 7 to 15 carbon atoms, aryl groups having 6 to 10 carbon atoms, or alkyl groups having 1 to 4 carbon atoms. Alternatively, it is a 1,1,2,2-tetrahydroperfluoroalkyl group (the perfluoroalkyl moiety of this group consists of 6 to 16 carbon atoms).

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

Further, the benzotriazole compound may be a multimer containing the compound of the above general formula (1) or the above general formula (2) as a partial structure. Examples of the multimer include the above-mentioned E ¹ or the above-mentioned compound in which E ² is a linking group. As the compound in which the above E ¹ or the above E ² is a linking group, one or more hydrogen atoms are excluded from E ¹ or E ² in the compound of the above general formula (1) or the above general formula (2). , The structure in which the compound of the general formula (1) or the above general formula (2) is linked in this portion can be mentioned. The multimer includes, for example, a -COOH group derived from the compound of the general formula (1) or the above general formula (2), and a -OH group derived from a diol (for example, ethylene glycol, propylene glycol, etc.). It may be a compound having a structure in which an ester bond is formed between the two.

The multimer is preferably a dimer, and examples thereof include structures such as the following exemplified compound A.

Examples of the benzotriazole compound include methyl 3- (3- (2H-benzotriazole-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate and methyl 3- (3- (2H-benzotriazole-2). -Il) -5-tert-butyl-4-hydroxyphenyl) Propionate reaction product with polyethylene glycol (methyl 3- (3- (2H-benzotriazole-2-yl) -5-tert-butyl-4- Hydroxyphenyl) propionate polyethylene glycol adduct, or a dimer of methyl 3- (3- (2H-benzotriazole-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate via polyethylene glycol, etc. (Eg, the above-mentioned exemplary compound A), or a mixture containing them), 2- (2H-benzotriazole-2-yl) -6- (1-methyl-1-phenylethyl) -4-1,1 , 3,3-Tetramethylbutyl) phenol (exemplified compound 1 above), 2- (2'-hydroxy-3', 5'-ditert-amylphenyl) benzotriazole (exemplified compound 6 above) 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 has 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, and 6 to 18 carbon atoms. It 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 alkoxys having 1 to 12 carbon atoms. It may be substituted with a group or interrupted with 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 independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkenyl group having 3 to 8 carbon atoms.

^At least one of R3 is a hydroxy group, and when it is not a hydroxy group, it represents a hydrogen atom.

R ⁴ independently represents a hydrogen atom or OR ¹ .

Examples of the linear or branched alkyl group having 1 to 12 carbon atoms represented by R ¹ of the general formula (3) include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-. 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, dodecyl and the like.

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

Examples of the aryl group having 6 to 18 carbon atoms represented by ^R1 of the general formula (3), the alkylaryl group having 7 to 18 carbon atoms or the alkenylaryl group having 7 to 18 carbon atoms include phenyl and 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-ditert-butylphenyl, 2,5-ditert-butylphenyl, 2,6-di-tert-butylphenyl, 2,4-di Examples thereof include tert-pentylphenyl, 2,5-ditert-amylphenyl, 2,5-ditert-octylphenyl, biphenyl, 2,4,5-trimethylphenyl, and the like as an arylalkyl group having 7 to 18 carbon atoms. Examples include benzyl, phenethyl, 2-phenylpropane-2-yl, diphenylmethyl and the like.

In the general formula (3), as the alkenyl group having 3 to 8 carbon atoms represented by R ¹ and R ² , for example, linear and branched propenyl, butenyl, pentenyl, hexenyl, heptenyl and octenyl are unsaturated. It 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 and amyl. Examples thereof include tert-amyl, octyl and tert-octyl, and among them, the methyl group is preferable because it has an excellent ability to absorb ultraviolet rays.

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

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

Further, as the ultraviolet absorber, a polymer type ultraviolet absorber may be used. Examples of the polymer-type ultraviolet absorber include (co) polymers having an ultraviolet-absorbing group, for example, a homopolymer of an ultraviolet-absorbing monomer, an ultraviolet-absorbing monomer, and other single amounts. A copolymer with a body can be preferably mentioned. The ultraviolet-absorbing monomer is preferably an ethylenically unsaturated monomer, for example, a benzotriazole skeleton, a benzophenone skeleton, a triazine skeleton, a benzoxazine skeleton, etc. in the ester substituent of the (meth) acrylic acid ester. Examples thereof include compounds containing. The other monomer may be a monomer copolymerizable with the ultraviolet absorbing monomer, for example, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, and the like. Alkyl (meth) acrylates such as propyl (meth) acrylates and butyl (meth) acrylates, hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylates, hydroxypropyl (meth) acrylates, and hydroxybutyl (meth) acrylates are available. Can be mentioned. 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 these, (meth) acrylic acid or methyl (meth) acrylate is preferable, methacrylic acid or methyl methacrylate is more preferable, and methyl methacrylate is further preferable.

The polymer-type ultraviolet absorber is preferably a polymer-type 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). , A polymer-type ultraviolet absorber having a triazine group or a benzotriazole group is more preferable, and a polymer-type ultraviolet absorber having a benzotriazole group is further preferable. The polymer-type ultraviolet absorber having a benzotriazole group is not particularly limited, and examples thereof include 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 all indicate the molar ratio of each structural unit represented by the general formula (4), and a + b + c = 1. A and b indicate a number greater than or equal to 0, and c indicates a number other than 0.)
From the viewpoint of ultraviolet absorption ability, in the general formula (4), c is preferably 0.3 or more, more preferably 0.5 or more, and the preferable upper limit value is 0.8 or less.

Further, R ¹⁰ to R ¹³ are preferably methyl groups. 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 polymer type ultraviolet absorber is 1,000 or more, and the weight average molecular weight is preferably 150,000 or less, preferably 3,000 to 100,000, from the viewpoint of ultraviolet absorption ability and solubility in the resin composition. Is more preferable, 5,000 to 80,000 is even more preferable, and 10,000 to 80,000 is particularly preferable. The weight average molecular weight of the polymer type ultraviolet absorber is a value obtained by polystyrene conversion by GPC.

As the ultraviolet absorber, a commercially available product may be used. The commercial product is not particularly limited, and examples of the benzotriazole-based compound include Tinuvin (registered trademark) 1130, Tinuvin (registered trademark) 928 manufactured by BASF Japan Ltd., and JF-80 manufactured by Johoku Chemical Industry Co., Ltd. However, as the triazine-based compound, Tinuvin (registered trademark) 477 manufactured by BASF Japan Ltd. and as the benzophenone-based compound, Uvinul (registered trademark) 3049 manufactured by BASF Japan Ltd. are used as the high molecular weight ultraviolet absorber. , Vanaresin UVA-5080 manufactured by Shin-Nakamura Kogyo Co., Ltd., UVA1935LH manufactured by BASF, etc., respectively.

As the ultraviolet absorber contained in the hard coat layer, benzo is used from the viewpoint of reducing the failure of the polarizing plate at the time of punching out the deformed shape and improving the adhesiveness between the polarizing element protective film and the polarizing element after a lapse of time at high temperature. It is particularly preferable that it is a triazole-based compound. 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 polymer-type ultraviolet absorber having a benzotriazole group, may be used. Extremely preferable.

The lower limit of the molecular weight of the ultraviolet absorber contained in the hard coat layer is from the viewpoint of reducing the failure at the time of punching out the deformed shape of the polarizing plate and improving the adhesiveness between the polarizing element protective film and the polarizing element after aging at high temperature. Therefore, it is preferably 300 or more. The molecular weight of the ultraviolet absorber is more preferably 700 or more, still more preferably 900 or more, from the viewpoint of further improving the adhesiveness between the polarizing element protective film and the polarizing element after a lapse of time at high temperature. It is particularly preferable that it is 1,000 or more. 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 total atomic weight of the ultraviolet absorbers other than the polymer type ultraviolet absorber, and gel permeation chromatography (GPC) is used for the polymer type ultraviolet absorber. It is the weight average molecular weight obtained by the polystyrene conversion by.

The ultraviolet absorber contained in the hard coat layer may 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 0.1 part by mass or more, more preferably 0.5 part by mass or more, with respect to 100 parts by mass of the ionized radiation curable compound. It is preferably 0.8 parts by mass or more, and particularly preferably 1 part by mass or more. Within this range, the ultraviolet ray blocking ability is further improved, and cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface at the time of punching out the deformed shape. 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, based on 100 parts by mass of the ionizing radiation curable compound. It is more preferably 3 parts by mass or less, and particularly preferably 2 parts by mass or less. Within this range, cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface during the 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 ionizing radiation curable compound in the cured product.

When the hard coat layer contains an ionizing radiation type 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 later. (In the present specification, it is contained in the hard coat layer with respect to the content (mass part) 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 of the ultraviolet absorber to 100 parts by mass of the ionized radiation curable compound (parts by mass), that is, the content of the ultraviolet absorber to 100 parts by mass of the ionized radiation curable compound (parts by mass) contained in the hard coat layer. / 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) may be 0.05 to 1. It is preferably 0.1 to 0.7, more preferably 0.1 to 0.5, and particularly preferably 0.1 to 0.3. Within this range, cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface during the irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the stator is further improved. The reason for this is that in the above range, the curl balance of the polarizing plate as a whole becomes good, curling occurs in the polyester resin film over time at high temperatures, and fine curling occurs in different states depending on the location in the polarizing plate surface. It is speculated that this is because The above mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention.

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

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

Examples of the metal constituting the metal particles include Au, Ag, Cu, Al, Fe, Ni, Pd, Pt and the like. Examples of the metal oxide constituting the metal oxide particles include tin oxide (SnO ₂ ), antimony oxide (Sb _{2O 5} ), antimony tin oxide (ATO) (for example, ammostin-doped tin oxide), and indium tin. Examples thereof include oxide (ITO), aluminum zinc oxide (AZO), tin fluorinated oxide (FTO), ZnO and the like. Examples of the coating particles include conventionally known particles having a structure in which a light-reflecting coating layer is formed on the surface of core particles. The core particles are not particularly limited, and examples thereof include 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-reflecting coating layer is not particularly limited, and examples thereof include the above-mentioned metals or alloys thereof, and the above-mentioned metal oxides.

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

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

Commercially available products may be used as the light-reflecting particles. Examples of commercially available products include ELCOM NY-1019ATV manufactured by Catalyst Kasei Kogyo Co., Ltd., which is a 20 mass% modified alcohol dispersion of antimony-doped tin oxide.

The light-reflecting particles may be used alone or in combination of two or more.

In the present specification, the "thickness of the hardcoat layer" in the case of the hardcoat layer containing light-reflecting particles means the thickness of the portion not containing the particles protruding from the layer.

The content of the light-reflecting particles is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, and further 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 ionizing radiation curable compound in the cured product.

[Other additives]
In the ionizing radiation curable resin composition, as other additives, fillers such as abrasion resistant agents, matting agents, scratch resistant fillers, mold release agents, dispersants, leveling agents, and hindered amine-based 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, and 2 It is particularly preferably about 5 μm. Within this range, the ultraviolet ray blocking ability is further improved, and cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface at the time of punching out the deformed shape. The thickness of the hard coat layer can be calculated from the average value of the values at 20 points by measuring the thickness at 20 points from the image of the cross section taken by, for example, a scanning transmission electron microscope (STEM). 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 of the hard coat layer (μm) to the thickness (μm) of the cycloolefin resin film or acrylic resin film described later (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, further preferably 0.08 to 0.5, and 0.08 to 0.4. It is particularly preferable that there is, and it is extremely preferable that it is 0.1 to 0.4. Within this range, cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface during the irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the stator is further improved. The reason for this is that in the above range, the curl balance of the polarizing plate as a whole becomes good, curling occurs in the polyester resin film over time at high temperatures, and fine curling occurs in different states depending on the location in the polarizing plate surface. It is speculated that this is because The above mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention.

[Method of forming a hard coat layer]
For the hard coat layer, a hard coat layer coating solution containing an ionizing radiation curable resin composition having a desired thickness after curing is applied onto a polyester resin film, dried as necessary, and then ionizing radiation. It can be formed by irradiating and curing.

The method and conditions for preparing, coating, drying and irradiating the ionization irradiation line of the hard coat layer coating liquid are not particularly limited, and a known method can be appropriately selected and used.

The coating liquid for hard coat is a homogeneous mixture of an ionizing radiation curable compound, an ultraviolet absorber, and light-reflecting particles and other additives used as necessary, in a solvent as necessary, at a predetermined ratio. Can be prepared.

The solvent is not particularly limited, but is, for example, water, hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone), esters. Classes (methyl acetate, ethyl acetate, methyl lactate), glycol ethers, other organic solvents and the like can be appropriately selected, or these can be mixed and used.

The content of the solvent in the hard coat layer coating liquid is not particularly limited, but is preferably 10 to 80% by mass, more preferably 20 to 80% by mass, and 20 to 20 to 80% by mass with respect to the total mass of the coating liquid. It 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 liquid thus prepared is applied to the surface of the polyester resin film or the functional layer provided on the polyester resin film with a die coat, a bar coat, a roll coat, a slit coat, a slit reverse coat, and a reverse roll. It is applied by a coat, a gravure coat, etc. and dried as necessary to form an uncured resin layer.

The drying conditions after coating are not particularly limited, but 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 irradiated with ionizing radiation such as an electron beam and ultraviolet rays to cure the uncured resin layer. As a method of irradiating the ionizing radiation, it is preferable to irradiate the uncured resin layer from the surface 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 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, or the like is used.

Since the conditions such as the irradiation wavelength, the illuminance, and the amount of light of the ultraviolet rays at this time differ depending on the type of the ionizing radiation curable compound and the polymerization initiator used, the conditions can be appropriately adjusted by those skilled in the art. For example, the amount of irradiation energy is preferably 50 to 1500 mJ / cm ² .

(Cycloolefin resin film or acrylic resin film)
The 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 a film containing a cycloolefin polymer and a (meth) acrylic polymer in an amount of 50% by mass or more based on the total mass of the film, respectively. If the content of the cycloolefin polymer or (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 (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, and more preferably 97% by mass or less. 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 blocking ability is further improved. Further, cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface during the irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the stator is further improved. It should be noted that 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 of these is added. 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. It refers to the film itself that can be made, and does not include other functional layers.

Of 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 polarizing element protective film arranged on both sides of the polarizing element, particularly in the cycloolefin resin film itself, are further reduced in a part of the polarizing plate surface at the time of punching out the deformed shape. Further, after a lapse of time at a high temperature, the adhesiveness between the substituent protective films, particularly the cycloolefin resin film itself, which are arranged on both sides of these splitters, and the substituents 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). ) Etc. can be mentioned. 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, and the following general formula (hydrogenated polymer) is preferable. A (co) polymer obtained by ring-opening (co) polymerization of the cycloolefin monomer represented by 5), or a hydride (hydrogenated polymer) obtained by hydrogenating the (co) polymer. It is more preferable to have.

(In the formula, R ¹⁶ to R ¹⁹ are independently hydrogen atom, hydrocarbon group, halogen atom, hydroxy group, ester group, alkoxy group, cyano group, amide group, imide group, silyl group, or polar group or It is a hydrocarbon group substituted with a polar group. However, two or more of ^R16 to ^R19 may be bonded to each other to form an unsaturated bond, a monocyclic ring or a polycyclic ring, and this monocyclic ring may be formed. Alternatively, the polycycle may have a double bond or form an aromatic ring; R ¹⁶ and R ¹⁷ or R ¹⁸ and R ¹⁹ may form an alkylidene group. . P and m are independent integers of 0 or more.)
In the above 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, and further preferably hydrogen. It represents an atom or a hydrocarbon group having 1 to 2 carbon atoms, particularly preferably a hydrogen atom. R ¹⁷ and R ¹⁹ are preferably hydrogen atoms or monovalent organic groups, 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, still more preferably m + p = 0 to 2, particularly preferably m = 1 and p = 0. Is. The specific monomer having m = 1 and p = 0 is preferable in that the obtained 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, a cyano group and the like, and these polar groups include a linking group such as a methylene group. It may be bonded via. Further, 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 mentioned as a polar group. Among these, a carboxy group, a hydroxy group, an alkoxycarbonyl group (-COOR) or an aryloxycarbonyl group is preferable, a carboxy group, an alkoxycarbonyl group or an aryloxycarbonyl group is more preferable, and a carboxy group is further preferable.

Further, in the monomer in which at least one of R ¹⁷ and R ¹⁹ is a polar group represented by the formula- (CH ₂ ) _n COOR, the obtained cycloolefin polymer has a high glass transition temperature, a low moisture absorption property and various materials. It is preferable in that it has excellent adhesion.

In the above formula for a particular 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. It is a group, and the hydrocarbon group is most preferably an alkyl group.

Other specific examples of the cycloolefin monomer include, but are not limited to, cyclobutene, cyclopentene, cycloheptene, cyclooctene, dicyclopentadiene, norbornene and the like. 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 4 to 20, more preferably 5 to 12.

The (co) polymer obtained by polymerizing the cycloolefin monomer represented by the above general formula (5) or its hydrogenated product (hydrogenated polymer) has a partial structure derived from the following general formula (6). It is preferably a cycloolefin polymer having.

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

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

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

The cycloolefin polymer may be used alone or in combination of two or more.

[(Meta) acrylic polymer]
The (meth) acrylic polymer (acrylic resin) which is the 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 of (meth) acrylate. It is more preferable that it is a (co) polymer.

The (meth) acrylic polymer is not particularly limited, but the total polymer is 100% by mass, the constituent unit derived from methyl methacrylate is 51 to 100% by mass, and other monomers copolymerizable therewith. It is preferable that the derived structural unit is from 0 to 49% by mass from the viewpoint that a high-quality optical film can be obtained. Among these, it is more preferable that the structural unit derived from methyl methacrylate is 95 to 100% by mass and the structural unit derived from another monomer copolymerizable therewith is 0 to 5% by mass.

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

Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate or 2-ethylhexyl acrylate are preferable, and methyl acrylate or n -Butyl acrylate is more preferred, and methyl acrylate is even more preferred.

As a (meth) acrylic polymer capable of forming a highly transparent film with little change in performance even in a high temperature and high humidity environment, it contains an alicyclic alkyl group as a copolymerization component or is mainly molecular by intramolecular cyclization. It is preferably a (meth) acrylic polymer having a cyclic structure formed in the chain. Examples of the (meth) acrylic polymer having a cyclic structure formed in the molecular backbone include, for example, the (meth) acrylic containing the lactone ring-containing polymer described in paragraphs 0195 to 0202 of JP2012-13307A. Examples thereof include polymers, and preferred polymer compositions and synthetic methods are described in, for example, Japanese Patent Application Laid-Open No. 2012-066538 and Japanese Patent Application Laid-Open No. 2006-171464. Further, as another preferable embodiment, a polymer containing glutaric acid anhydride as a copolymerization component can be mentioned, and the copolymerization component and a specific synthesis method are described in, for example, Japanese Patent Application Laid-Open No. 2004-070296.

The lower limit of the weight average molecular weight (Mw) of the (meth) acrylic polymer is preferably 80,000 or more, and more preferably 100,000 or more. Within this range, the content of the organic solvent in the dope can be made smaller, the drying time can be made shorter, and the surface condition of the film can be made better. Further, 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 solution spreadability can be realized, and compatibility with organic solvents and additives can be improved at the time of dope preparation. The weight average molecular weight is a value obtained by polystyrene conversion by gel permeation chromatography (GPC).

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

As the (meth) acrylic polymer, a commercially available product may be used. Examples of commercially available products include Delpet (registered trademark) 60N and 80N manufactured by Asahi Kasei Chemicals Co., Ltd., and Dianal (registered trademark) BR52, BR80, BR83, BR85, BR88 manufactured by Mitsubishi Rayon Co., Ltd. K75 made by the manufacturer and the like can be mentioned.

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

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

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

The benzophenone 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 above general formula (1), and more preferably a compound represented by the above general formula (2). Further, the benzotriazole compound may be a multimer containing the compound of the above general formula (1) or the above general formula (2) as a partial structure. Among these, benzotriazole-based compounds include methyl 3- (3- (2H-benzotriazole-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate and methyl 3- (3- (2H-). Benzotriazole-2-yl) -5-tert-butyl-4-hydroxyphenyl) Reaction product of propionate with polyethylene glycol (methyl 3- (3- (2H-benzotriazole-2-yl) -5-tert- A polyethylene glycol adduct of butyl-4-hydroxyphenyl) propionate, or methyl 3- (3- (2H-benzotriazole-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate via polyethylene glycol. Multimers such as dimer (eg, the above-mentioned exemplified compound A) or a mixture containing them), 2- (2H-benzotriazole-2-yl) -6- (1-methyl-1-phenylethyl) -4 -1,1,3,3-tetramethylbutyl) phenol (exemplified compound 1 above), 2- (2'-hydroxy-3', 5'-di tert-amylphenyl) benzotriazole (exemplified compound 6 above) Especially preferable.

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

As the ultraviolet absorber, a polymer type ultraviolet absorber may be used. The high molecular weight ultraviolet absorber is preferably a high molecular weight ultraviolet absorber having a benzophenone group, a triazine group or a benzotriazole group, and may be a high molecular weight ultraviolet absorber having a triazine group or a benzotriazole group. More preferably, it is a high-molecular-weight ultraviolet absorber having a benzotriazole group. The polymer-type ultraviolet absorber having a benzotriazole group is not particularly limited, and examples thereof include a polymer-type ultraviolet absorber represented by the above general formula (4).

Since these details are the same as those of the ultraviolet absorber contained in the above-mentioned hard coat layer, the description thereof is omitted here.

As the ultraviolet absorber contained in the cycloolefin resin film or the acrylic resin film, the failure at the time of punching out the deformed shape of the polarizing plate is reduced, and the adhesiveness between the polarizing element protective film and the polarizing element after aging at high temperature is improved. 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 extremely preferable. Among these, a low-polarity triazine-based compound having one triazine skeleton in the molecule is extremely preferable from the viewpoint of further improving the adhesiveness between the polarizing element protective film and the polarizing element after aging at high temperature. .. The low-polarity triazine-based compound having one triazine skeleton in the molecule is not particularly limited, but a low-polarity hydroxyphenyltriazine (HPT) -based compound is more preferable, and the above-mentioned exemplary compound 18 is used. Is even more preferable.

The molecular weight of the ultraviolet absorber contained in the cycloolefin resin film or the acrylic resin film reduces the failure of the polarizing plate during irregular punching and improves the adhesiveness between the polarizing element protective film and the polarizing element after aging at high temperature. From the viewpoint of, it is preferably 250 or more and less than 1,000. Within 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 adhesiveness between the polarizing element protective film and the polarizing element after aging at high temperature. , 500 or more and less than 1,000, more preferably 800 or more and less than 1,000. The molecular weight of the ultraviolet absorber is a value calculated from the total atomic weight of the ultraviolet absorbers other than the polymer type ultraviolet absorber, and gel permeation chromatography (GPC) is used for the polymer type ultraviolet absorber. It is the weight average molecular weight obtained by the polystyrene conversion by.

The ultraviolet absorber contained in the cycloolefin resin film or the acrylic resin film may 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, preferably 3 parts by mass or more, based on 100 parts by mass of the cycloolefin polymer or the (meth) acrylic polymer. Is more preferable. Within this range, the UV blocking ability is further improved. Further, cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface during the irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the stator 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 with respect to 100 parts by mass of the cycloolefin polymer or the (meth) acrylic polymer, and is preferably 10 parts by mass. More preferably, it is less than or equal to a part. Within this range, cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface during the irregular punching. Further, after a lapse of time at a high temperature, the adhesiveness between these films and the stator 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 effect of imparting 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 because the turbidity of the film can be lowered.

Commercially available products can be used as the fine particles of silicon dioxide. Examples of commercially available products include Aerosil (registered trademark) R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 manufactured by Aerosil Japan.

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 with respect to 100 parts by mass of the cycloolefin polymer or (meth) acrylic polymer. It is more preferably 0.1 to 0.5 parts by mass.

[Other additives]
The cycloolefin resin film or acrylic resin film is known as a specific hydrocarbon-based resin described in, for example, JP-A-9-221577 and JP-A-10-287732, as long as the effects of the present invention are not impaired. It may contain other additives such as thermoplastic resins, thermoplastic elastomers, rubbery polymers and rubber particles.

[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 further preferably 20 μm or more. Within this range, the UV blocking ability is further improved. Further, cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface during the irregular punching. 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 polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, is satisfactorily exhibited in a part of the polarizing plate surface during irregular punching, and further thinning is possible. It will be realized.

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

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

Equation (I) Ro = (nx-ny) × d
Equation (II) Rth = {(nx + ny) /2-nz} × d
(However, nx represents the refractive index in the direction x at which the refractive index becomes maximum in the in-plane direction of the film, and 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 retardation Ro (590) in the in-plane direction measured at a wavelength of 590 nm is 20 to 100 nm under the conditions of 23 ° C. and 55% RH, and is in the thickness direction. The retardation Rth (590) is preferably 70 to 300 nm. A protective film having a retardation in the above range is suitable as a retardation film such as a VA type liquid crystal cell.

The in-plane retardation Ro and the thickness direction retardation Rth of the retardation film for light having a wavelength of 590 nm under the environment of 23 ° C. and 55% RH can be measured by the following methods:
1) The retardation film is adjusted in humidity at 23 ° C. and 55% RH. Measure the average refractive index of the retardation film after humidity control with an Abbe refractometer or the like;
2) Ro is measured by KOBRA-21DH (manufactured by Oji Measuring Instruments Co., Ltd.) when light having a measurement wavelength of 590 nm is incident on the retardation-controlled retardation film in parallel with the normal on the surface of the film;
3) With KOBRA-21ADH, the in-plane slow axis of the retardation film is set as the tilt axis (rotation axis), and the measurement wavelength is 590 nm from the angle of θ (incident angle (θ)) with respect to the normal of the surface of the film. The retardation value R (θ) when the light of the above is incident is measured. The retardation value R (θ) can be measured at 6 points every 10 ° in the range of 0 to 50 °. The in-plane slow-phase axis refers to the axis in the film surface that has the maximum refractive index, and can be confirmed by KOBRA-21ADH;
4) From the measured Ro and R (θ), the above-mentioned average refractive index and the thickness of the film, nx, ny and nz are calculated by KOBRA-21ADH, and Rth at the measurement wavelength of 590 nm is calculated. The retardation measurement can be performed under 23 ° C. and 55% Rhesus conditions.

(B) As for the retardation of the retardation film, it is preferable that the retardation Ro in the in-plane direction is substantially λ / 4. In the present specification, the in-plane retardation Ro of the film is substantially λ / 4, which means that the in-plane retardation Ro measured at a wavelength of 550 nm under the conditions of 23 ° C. and 55% RH (in-plane retardation Ro). It means that 550) is in the range of 120 to 180 nm.

Further, 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 under the conditions of 23 ° C. and 55% RH. The value (Ro (450) / Ro (550)) of the ratio of the retardation Ro (450) in the in-plane direction measured at a wavelength of 450 nm to (550) is in the range of 0.72 to 1.05. Is preferable. Further, the retardation film has an in-plane retardation Ro (550) measured at a wavelength of 550 nm as opposed 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 in-plane retardation Ro of the retardation film for light at wavelength 450 nm, wavelength 550 nm and wavelength 650 nm under the environment of 23 ° C. and 55% RH is an automatic double refractive index meter Axo Scan (Axo Scan Mueller Matrix Polarimeter). It can be measured by measuring the double refractive index at each wavelength using (manufactured by Trix).

A retardation film in which the retardation Ro in the in-plane direction is substantially λ / 4 can be used as the 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.

A circular polarizing plate is obtained by laminating the λ / 4 retardation film so that the angle between the in-plane slow-phase axis and the transmission axis of the substituent is substantially 45 °. As used herein, "substantially 45 °" means within the range of 45 ± 5 °. The angle between the in-plane slow-phase axis of the λ / 4 retardation film and the transmission axis of the splitter is preferably in the range of 41 to 49 °, more preferably in the range of 42 to 48 °. , 43 to 47 °, more preferably 44 to 46 °, and particularly preferably 44 to 46 °.

The phase difference between the above (a) and the above (b) is 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, and the like. It can be controlled by stretching conditions such as stretching ratio and stretching ratio, and the thickness of the film.

[Functional 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 the polarizing plate and the polarizing element protective film can be appropriately selected. Examples of the functional layer include a hard coat layer, an easy-adhesive layer, an anti-glare layer, an anti-reflection layer, a low-reflection layer, a low-reflection anti-glare layer, an anti-reflection anti-glare layer, an anti-static layer, a silicone layer, an adhesive layer, and an anti-glare layer. Examples include a dirty layer, a fingerprint resistant layer, a water repellent layer, and a blue cut layer.

[Manufacturing method of 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 of reducing the amount of decrease in the ultraviolet absorber due to volatilization and decomposition in the manufacturing process. In the cycloolefin resin film or acrylic resin film produced by the solution casting method, the ultraviolet ray blocking ability is further improved. Further, in the film, cracks generated in the polarizing element protective film, particularly the cycloolefin resin film and the acrylic resin film, are further reduced in a part of the polarizing plate surface at the time of punching out the deformed shape. Further, in the film, the adhesiveness between these films and the stator is further improved after a lapse of time at a high temperature.

In the solution casting method, a solution in which a cycloolefin polymer or a (meth) acrylic polymer, an ultraviolet absorber and other additives which may be added optionally is dissolved is spread on a substrate, dried on the substrate, and then a film-like substance is formed. This is a method in which (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 which may be optionally added is heated and melted, cast on a substrate, and cooled and solidified. It is a method of forming a film. In these production methods, stretching may be performed during or after the film formation, if necessary.

Hereinafter, the solution casting method, which is a preferable 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 step of stretching in a drying process during film formation, or a step of unwinding a film (film raw material) wound 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 preparing a dope solution by dissolving each of the above-mentioned components in a solvent.
2) The process of casting the dope solution onto 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 the web and stretching it if necessary (film drying step),
It is preferable that the product is manufactured via.

Further, after 4) above, optionally,
5) A step (hereinafter, also referred to as "post-film-forming stretching") of unwinding and then stretching the film raw material wound after film-forming (post-film-forming stretching step).
May have.

Examples of the solvent used in the above step 1) include chlorine-based solvents such as chloroform and dichloromethane; aromatic solvents such as toluene, xylene, benzene, and mixed solvents thereof; methanol, ethanol, and propanol (n-propanol). , Isopropanol), butanol (n-butanol, isobutanol, 2-butanol, tert-butanol) and other alcoholic solvents; methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, dimethylformamide, dimethylsulfoxide, dioxane, cyclohexanone, Examples thereof include tetrahydrofuran, acetone, methyl ethyl ketone (MEK), ethyl acetate, diethyl ether; and the like.

In the solution casting method, it is preferable that the concentration of the cycloolefin polymer or (meth) acrylic polymer in the dope is high because the drying load after casting on the substrate can be reduced, but if the concentration is too high, the concentration is high during filtration. The load on the filter increases and the filtration accuracy deteriorates. The concentration at which these are compatible is preferably 10 to 35% by mass, more preferably 15 to 35% by mass. The surface of the substrate in the casting process is preferably mirror-finished, and a stainless steel belt (stainless steel belt) or a drum whose surface is plated with a casting is preferable.

The dope temperature at the time of casting is preferably such that the dope has fluidity to the extent that the dope can be cast, and the solvent in the dope is at least the boiling point. The dope 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 to 4 m. The surface temperature of the substrate in the casting step is set from −50 ° C. to a temperature below which the solvent does not boil and foam. A higher temperature is preferable because the drying speed of the web can be increased. Further, within this temperature range, there is no concern that the web will foam or the flatness will deteriorate.

The preferable substrate temperature is appropriately determined in the range of 0 to 100 ° C., and more preferably in the range of 5 to 30 ° C. Alternatively, it is also a preferable method to gel the web by cooling the substrate and peel it off from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the substrate is not particularly limited, but there are 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 until the temperature of the substrate becomes constant is short because heat transfer is efficiently performed. When using warm air, consider the temperature drop of the web due to the latent heat of vaporization of the solvent, and use hot air above the boiling point of the solvent while preventing foaming and using air at a temperature higher than the target temperature. There is. In this case, it is preferable to change the temperature of the substrate and the temperature of the drying air between casting and peeling to efficiently perform drying.

From the viewpoint that the cycloolefin resin film or the acrylic resin film exhibits good flatness, the amount of residual solvent when peeling the web from the substrate is preferably in the range of 10 to 150% by mass, more preferably 20 to 40. It is in the range of% by mass or 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 (mass%) = {(MN) / N} x 100
In addition, 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 after heating M at 115 ° C. for 1 hour.

In the drying step, it is preferable to reduce the amount of residual solvent in the obtained cycloolefin resin film or acrylic resin film by peeling the web from the substrate and further drying it. 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 further preferably in the range of 0 to 0.01% by mass.

The film drying step is not particularly limited, but generally, a roller drying method (a method in which the web is alternately passed through a large number of rollers arranged above and below to dry) or a method in which the web is conveyed by a tenter and dried is adopted.

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, preferably 5% by mass or less, from the viewpoint of suppressing an increase in haze. As a method of keeping the residual solvent at 10% by mass or less at the start of stretching, a method of peeling 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 of applying a peripheral speed difference to a plurality of rolls and stretching in the MD direction using the roll peripheral speed difference between them, and a clip or pin on both ends of the film-like object by a tenter. A method of fixing with a clip or pin and widening the clip or pin spacing in the MD direction (transportation direction), fixing both ends of the web with clips or pins using a tenter, and setting the clip or pin spacing in the TD direction (with respect to the transport direction). A method of expanding and stretching in the vertical direction), a method of simultaneously expanding and stretching the clip and pin spacing in the MD direction and the TD direction (direction perpendicular to the transport direction), and the like can be adopted alone or in combination. .. Among these, stretching in the TD direction is preferably performed by a tenter. The type of tenter may be a pin tenter or a clip tenter. That is, it may be stretched in the TD direction, may be stretched in the MD direction, or may be stretched in both directions. Further, when stretching 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 because smooth stretching can be performed and the risk of breakage can be reduced.

In the stretching step, the stretching ratio in the TD direction or the MD direction in the direction in which the stretching ratio is larger is preferably 1 to 100% (1.01 to 2.00 times), more preferably 5 to 80% (1.05). It can be in the range of ~ 1.80 times), more preferably 12 to 60% (1.12 times 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 to) in the transport direction (MD direction). It can be 1.60 times), preferably 5 to 70% (1.05 to 1.70 times) in the width direction (TD direction), and more preferably 10 to 70% (1.10 to 1.70 times). The stretch ratio (%) is defined by the following formula. Here, when producing a retardation film having the retardation described in (a) above, it is preferably 20 to 70% (1.20 to 1.70 times) in the width direction (TD direction).

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 may be in the range of 120 to 180 ° C., preferably 140 to 180 ° C., more preferably 145 to 165 ° C.

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

As the diagonal stretching method in the film drying step and the post-film forming stretching step, known methods can be appropriately adopted. For example, the method described in paragraphs 0110 to 0124 of JP-A-2016-212146 can be adopted with appropriate modifications, but the diagonal stretching method is not limited thereto.

By drying the web by the film drying step, a cycloolefin resin film or an acrylic resin film can be obtained.

The cycloolefin resin film or acrylic resin film after film formation is preferably rolled into a roll (film roll).

As for other steps in the solution casting method, various steps that can be included in the known solution casting method can be appropriately adopted. For example, the same steps as those in paragraphs 0109 to 0140 of JP2012-48214 can be adopted, but the other steps are not limited thereto.

As for 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. 5509515, the method described in paragraphs 0224 to 0230 of Japanese Patent Application Laid-Open No. 2016-1583839, and the like can be adopted above with appropriate modifications. .. However, the applicable melt casting method is not limited to these.

Further, the film is formed by the above-mentioned solution casting method or melt casting method, and the wound film raw fabric is unwound and then stretched (stretched after film formation) to obtain a 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, the same method as the stretching described in the film drying step in the above-mentioned solution casting method can be preferably used. At this time, for details of the stretching method after film formation, in the above-mentioned film drying step, the amount of residual solvent at the start of stretching is read as the amount of residual solvent after the drying step, and the above-mentioned web is read as the original film. Can be explained in. The stretching temperature in stretching after film formation is not particularly limited, but the temperature of the preheating zone is in the range of Tg to (Tg + 30) ° C. with respect to the glass transition temperature Tg of the cycloolefin polymer or acrylic polymer. It is preferable to set the temperature in the range of Tg to (Tg + 30) ° C. and the temperature of the cooling zone in the range of (Tg-30) to Tg ° C.

(Polarizer)
The polarizing element is an element that allows only light on a plane of polarization in a certain direction to pass through, and a typical polarizing element currently known is a polyvinyl alcohol (PVA) -based polarizing film (polarizer). The polyvinyl alcohol-based polarizing film includes a polyvinyl alcohol-based film dyed with iodine and a polyvinyl alcohol-based film dyed with a dichroic dye.

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

As the polyvinyl alcohol-based film, a commercially available product may be used. As commercially available products, for example, Kuraray Vinylon PE3000, PE6600, etc. manufactured by Kuraray Co., Ltd. can be used.

The modified polyvinyl alcohol is not particularly limited, but for example, the ethylene unit content described in JP-A-2003-248123, JP-A-2003-342322, etc. is 1 to 4 mol%, the degree of polymerization is 2000 to 4000, and Ken. Ethylene-modified polyvinyl alcohol having a degree of polymerization of 99.0 to 99.99 mol% or the like is used. Of these, an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73 ° C. is preferably used.

The thickness of the polarizing element 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 a polarizing element, a known method can be appropriately adopted. For example, the methods described in paragraphs 0133 to 0134 and the like of JP-A-2014-010207 can be adopted with appropriate modifications, but the method for producing a splitter 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 polarizing element. When these films further have a functional layer, the bonding may be performed by bonding the surface of the functional layer and the surface of the stator. 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 polarizing element protective films that protect different surfaces of the substituents. Become.

The method for producing the polarizing plate is not particularly limited, and a known method can be applied. In the production of the polarizing plate, the polyester resin film, the cycloolefin resin film, the acrylic resin film and the polarizing element are corona discharge treatments on the polyester resin film, the cycloolefin resin film or the acrylic resin film, or the functional layer contained therein. It can be bonded by performing a known surface treatment such as a plasma treatment and an alkali saponification treatment and using a known adhesive.

Regarding the surface treatment, one or more functional layers, for example, an easy-adhesion layer, may be formed on the surface of the polyester resin film, the cycloolefin resin film, or the acrylic resin film on the bonding surface side with the polarizing element. When other functional layers are formed, the outermost surface of these functional layers may be surface-treated.

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

The side surface of the polyester resin film on which the hard coat layer is not formed, one surface of the cycloolefin resin film or the acrylic resin film, and the polarizing element are a polyvinyl alcohol aqueous solution (water glue) or an active energy ray-curable adhesive. It is preferable that they are bonded by a known adhesive such as. Among these adhesives, it is preferable to use an aqueous solution of polyvinyl alcohol (water glue). The polyvinyl alcohol aqueous solution (water glue) is preferably a completely saponified polyvinyl alcohol aqueous solution (water glue). As the polyvinyl alcohol aqueous solution (water glue), a commercially available product may be used. Examples of commercially available products include PVA-117H manufactured by Kuraray Co., Ltd. If a functional layer (for example, an easy-adhesive layer or another functional layer) is formed on the bonding surface side of the polyester resin film, the cycloolefin resin film, or the acrylic resin film with the polarizing element, these The outermost surface of the functional layer and the polarizing element may be bonded to each other 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 freeform display (FFD). From this, it is preferable that the polarizing plate according to one embodiment of the present invention is cut into a free shape and irregular shape from the viewpoint that the effect of the present invention can be more exhibited, not only the conventional square and rectangular shapes. The irregularly shaped cut shape is not particularly limited, and examples thereof include a circular diameter, an elliptical shape, and a deformed panel shape 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 provided with a polarizing plate according to the embodiment of the present invention.

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

Further, the use of the polarizing plate according to one embodiment of the present invention is not particularly limited, but since the polarizing element protective film has excellent water resistance, it can be used as a display device for in-vehicle use under harsh conditions. It is preferable to be 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 transmissive liquid crystal display device, the liquid crystal display device has a liquid crystal cell in which a liquid crystal is sandwiched between a transparent substrate and the other transparent substrate. The polarizing plate according to one embodiment of the present invention is preferably arranged on the outside of at least one of these transparent substrates, either directly or via another member.

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 polarizing element, and polyester with a hard coat layer. It is preferable that the film is arranged so as to face the polarizing element on the opposite side of the display panel (liquid crystal cell, OLED cell).

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

Further, the polarizing plate according to one embodiment of the present invention can also be preferably used as a protective film for an image display device provided with a touch panel, an image display device such as a plasma display, or the like.

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

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

<Manufacturing of polyester resin film>
(Polyester resin film P1)
[Preparation of polyester resin (A)]
The temperature of the esterification reaction vessel was raised, 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were added at 200 ° C., and 0.017 parts by mass of antimony trioxide was added as a catalyst while heating and stirring. , 0.064 parts by mass of magnesium acetate tetrahydrate and 0.16 parts by mass of triethylamine were added. The pressure esterification reaction was carried out under the conditions of a gauge pressure of 0.34 MPa and a temperature of 240 ° C. Then, 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, the dispersion treatment was carried out with a high-pressure disperser, and after another 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction can, and a polycondensation reaction was carried out under reduced pressure at 280 ° C. After completion of the polycondensation reaction, filtration is performed with a Naslon (registered trademark) filter NF-05S manufactured by Nippon Seisen Co., Ltd., extruded into strands from a nozzle, filtered in advance (pore size: 1 μm or less), and then cooled. The resin was cut into pellets by cooling and solidifying with water. The obtained polyester resin (polyethylene terephthalate resin) (A) contained substantially no inert particles and internally precipitated particles (hereinafter, also referred to as PET (A)).

[Preparation of easy-adhesive layer coating liquid]
Ester exchange reaction and polycondensation reaction were carried out by a conventional method, and 46 mol% of terephthalic acid, 46 mol% of isophthalic acid and 8 mol% of sodium 5-sulfonatoisophthalate were carried out as dicarboxylic acid components (relative to the entire dicarboxylic acid component). Was used to prepare a water-dispersible metal sulfonate metal base-containing copolymerized polyester resin containing 50 mol% of ethylene glycol and 50 mol% of neopentyl glycol as the diol component (relative to the entire diol component).

Next, 51.4 parts by mass of water, 38 parts by mass of isopropyl alcohol, 5 parts by mass of n-butyl cell solution, and 0.06 parts by mass of a nonionic surfactant were mixed, heated and stirred, and after reaching 77 ° C., After adding 5 parts by mass of the water-dispersible metal sulfonic acid base-containing copolymerized polyester resin and continuing heating and stirring until the resin is no longer clumped, the resin water dispersion is cooled to room temperature to have a solid content concentration of 5. A uniform water-dispersible copolymerized polyester resin liquid of 0% by mass was obtained. Further, 3 parts by mass of aggregate silica particles (manufactured by Fuji Silysia Chemical Ltd., Cylysia 310) were dispersed in 50 parts by mass of water. 0.54 parts by mass of the aqueous dispersion of Syricia 310 was added to 99.5 parts by mass of the water-dispersible copolymerized polyester resin liquid, and 20 parts by mass of water was added with stirring to prepare an easy-adhesion layer coating liquid.

[Manufacturing of polyester resin film]
The polyester resin (A) prepared above is dried by a conventional method, supplied to an extruder, melted at 285 ° C., and this polymer is filtered with a filter medium of a stainless sintered body (nominal filtration accuracy of 10 μm particles 95% cut). After extruding into a sheet from the base, the film was wound around a casting drum having a surface temperature of 30 ° C. and solidified by cooling to produce an unstretched polyester resin film (PET film).

Next, the easy-adhesive layer coating liquid prepared above was applied to both sides of the unstretched PET film by the reverse roll method so that the coating amount after drying was 0.08 g / m ² , and then the temperature was 80 ° C. for 20 seconds. It was dry.

The unstretched film on which the easy-adhesion layer was formed was guided to a tenter stretching machine, and while gripping the end of the film with a clip, it was stretched 1.5 times in the width direction in a heating zone having a temperature of 125 ° C. Next, while maintaining the width stretched in the width direction, the film was 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 was 70 μm. , A uniaxially oriented PET film having a thickness of 1 μm or less for each easy-adhesive layer was produced. This film was designated as a polyester resin film P1.

In-plane retardation Ro (590) for light with a wavelength of 590 nm under the environment of 23 ° C. and 55% RH of polyester resin film P1, automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). ), It was Ro = 790 nm.

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

In-plane retardation Ro (590) for light with a wavelength of 590 nm under the environment of polyester resin film P2 at 23 ° C. and 55% RH, the automatic birefringence index meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). ), It was Ro = 290 nm.

(Polyester resin film P3)
[Preparation of polyester resin (B)]
When the temperature of the esterification reaction can 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 0.017 parts by mass of antimony trioxide was added as a catalyst while stirring. 0.064 parts by mass of magnesium acetate tetrahydrate and 0.16 parts by mass of triethylamine were charged. Then, the pressure was raised and the pressure was increased, and the pressure esterification reaction was carried out under the conditions of a gauge pressure of 0.34 MPa and 240 ° C., the esterification reaction can 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. Then, after 15 minutes, the dispersion treatment was carried out with a high-pressure disperser, and after 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction can, and the polycondensation reaction was carried out under reduced pressure at 280 ° C. After completion of the polycondensation reaction, filtration is performed with a Naslon filter having a 95% cut diameter of 5 μm, extruded into strands 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) contained substantially no inert particles and internally precipitated particles (hereinafter, also referred to as PET (B)).

[Preparation of polyester resin (C)]
Mix 10 parts by mass of dried UV absorber 2,2'-(1,4-phenylene) bis (4H-3,1-benzoxadinone-4-one) and 90 parts by mass of PET (B) containing no particles. Then, a polyester resin (polyethylene terephthalate resin composition) (C) containing an ultraviolet absorber was obtained using a kneading extruder (hereinafter, also referred to as PET (C)).

[Manufacturing of polyester resin film]
A three-layer base film was produced. Specifically, 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 used as raw materials for the intermediate layer of the base film at 135 ° C. After drying under reduced pressure (1 Torr) for 6 hours, the mixture was supplied to extruder 2 (for intermediate layer II layer) and dissolved at 285 ° C. Further, as a raw material for the outer layer of the base film, PET (B) was dried by a conventional method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III layer), respectively, and dissolved at 285 ° C. These two types of polymers are filtered with a filter medium of a stainless sintered body (nominal filtration accuracy of 10 μm particles 95% cut), laminated in a two-type three-layer confluence block, extruded into a sheet from the base, and then extruded. An unstretched film was produced by winding it around a casting drum having a surface temperature of 30 ° C. and cooling and solidifying it using an electrostatic application casting method. At this time, the discharge amount of each extruder was adjusted so that the ratio of the thicknesses of the I layer, the II layer, and the III layer was 10:80:10.

Next, the unstretched PET film was prepared by the reverse roll method in the same manner as the preparation of the easy-adhesive layer coating liquid in the preparation of the polyester resin film P1 so that the coating amount after drying on both sides of the unstretched PET film was 0.08 g / m ² . After applying the easy-adhesion coating liquid, the mixture was dried at 80 ° C. for 20 seconds.

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

<Formation of hard coat layer>
(Preparation of hard coat layer coating liquid HC1)
20% by mass of antimony-doped tin oxide-modified alcohol dispersion (ELCOM NY-1019ATV manufactured by JGC Catalysts and Chemicals Co., Ltd.) 50 parts by mass, UV absorber (Tinuvin (registered trademark) 1130 manufactured by BASF Japan Co., Ltd.) 1 part by mass, urethane 100 parts by mass of acrylate (UV-7600B, manufactured by JGC Chemical Industry Co., Ltd.), 3.8 parts by mass of photopolymerization initiator (Irgacure (registered trademark) 819, manufactured by Ciba Specialty Chemicals Co., Ltd.) 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 liquid HC2-7)
In the preparation of the hard coat layer coating liquid HC1, the hard coat layer coating liquid HC2 to the same except that the presence or absence of the UV absorber, the type of the UV absorber or the amount of the UV absorber added was changed as shown in Table 1 below. 7 was prepared.

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

(Formation of hard coat layer)
Regarding the combination of the polyester resin film and the hard coat layer coating liquid shown in Table 1 below, after drying each of the hard coat layer coating liquids obtained above on each of the polyester resin films obtained above by a slit reverse coating. A coating film was formed by applying so that the thickness of the above was as shown in Table 1 below. The obtained coating film was dried at 80 ° C. for 1 minute, and then irradiated with ultraviolet rays at an ultraviolet irradiation amount of 300 mJ / cm ² to cure the coating film, whereby it was obtained from each hard coat coating solution on each polyester resin film. The hard coat layer was formed. In this way, a polyester resin film with each hard coat layer was manufactured.

<Manufacturing 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® 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 manton golin.

5 parts by mass of the fine particle dispersion was slowly added to the well-stirred methylene chloride (100 parts by mass) in the dissolution tank. Further, the particles were dispersed by 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 fine particle additive solution.

[Preparation of main dope]
A main dope having the following composition was prepared. First, dichloromethane and ethanol were added to the pressurized dissolution tank. The following cycloolefin resin (cycloolefin polymer), an ultraviolet absorber, and a fine particle-added solution were put into a pressurized dissolution tank containing a mixed solution of dichloromethane and ethanol while stirring. This is heated and completely melted while stirring, and this is Azumi Filter Paper No. 1 manufactured by Azumi Filter Paper Co., Ltd. Filtration was performed using 244 to prepare the main dope.

Cycloolefin resin (ARTON (registered trademark) F4520, manufactured by JSR Corporation) 100 parts by mass,
Dichloromethane 200 parts by mass,
10 parts by mass of ethanol,
UV absorber (Tinuvin (registered trademark) 477, manufactured by BASF Japan Ltd.) 5 parts by mass,
3 parts by mass of the fine particle addition liquid prepared above.

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

[Manufacturing of cycloolefin resin film]
Then, using an endless belt casting device, the dope was uniformly cast on the stainless belt support at a temperature of 31 ° C. and a width of 1800 mm. The temperature of the stainless steel belt was controlled to 28 ° C. The solvent was evaporated on the stainless belt support until the amount of residual solvent in the cast dope reached 30% by mass. Then, the film-like material (web) was peeled off 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 under the condition of 160 ° C. The residual solvent of the web at the start of stretching was 5% by mass. Subsequently, the drying of the web is completed while the drying zone is conveyed by a large number of rollers, the end of the web sandwiched between the tenter clips is slit with a laser cutter, and then the dried web is wound up to 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, 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, but the cycloolefin resin films C2 to 5, 9 and 10 were similarly changed. 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 ultraviolet absorber contained in each cycloolefin resin film shown in Table 1 are shown below;
"Ti477": manufactured by BASF Japan Ltd., Tinuvin (registered trademark) 477, an ultraviolet absorber represented by the above chemical formula 18);
"3049": BASF, Uvinul® 3049, 2,2-dihydroxy-4,4-dimethoxybenzophenone;
-"Ti928": manufactured by BASF Japan Ltd., Tinuvin (registered trademark) 928, 2- (2H-benzotriazole-2-yl) -6- (1-methyl-1-phenylethyl) -4-1,1, 3,3-Tetramethylbutyl) Phenol;
-JF-80: JF-80, 2- (2'-hydroxy-3', 5'-ditert-amylphenyl) benzotriazole manufactured by Johoku Chemical Industry Co., Ltd .;
-"Chemical formula 17": Ultraviolet absorber represented by the following chemical formula 17

(Cycloolefin resin film C6)
In the production of the cycloolefin resin film C1, the film-like material (web) is peeled off, and then the peeled film raw fabric is described in paragraphs 0110 to 0124 of JP-A-2016-212146 under the conditions of 160 to 190 ° C. According to the diagonal stretching method, the tenter shown in FIG. 2 (A) of the relevant document was used to diagonally stretch the stretch direction at 45 degrees with respect to the longitudinal direction. At this time, the casting conditions were changed so that the thickness of the film formed through the stretching conditions after winding was 20 μm, and the stretching ratio was determined. Other than that, the cycloolefin resin film C6 having a size of 20 μm was produced in the same manner as in the production of the cycloolefin resin film C1.

For the cycloolefin resin film C6, an in-plane retardation Ro for light having a wavelength of 550 nm was used in an environment of 23 ° C. and 55% RH, using an automatic birefringence index meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). The in-plane retardation Ro (550) 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 under the condition of 160 ° C. was changed to 1.20 times, and the film formed under the stretching condition was flowed so that the thickness after winding was 20 μm. The cycloolefin resin film C7 was produced in the same manner except that the extension conditions were changed.

For the cycloolefin resin film C7, the average refractive index was measured by the Abbe refractive index system, and Ro and Rth at 590 nm were measured by KOBRA-21DH, Oji Measuring Instruments Co., Ltd., and found that Ro (590) = 30 to 60 nm. Rth (590) = 100 to 140 nm.

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

[Manufacturing of cycloolefin resin film]
The cycloolefin polymer prepared above was dried at 70 ° C. for 2 hours using a hot air dryer in which air was circulated to remove water, and then an ultraviolet absorber (Tinuvin (Tinuvin) was applied to 100 parts by mass of the cycloolefin polymer. (Registered trademark) 477, manufactured by BASF Japan Co., Ltd.) was added in an amount of 5 parts by mass. Then, this mixture was subjected to molding conditions of a molten resin temperature of 240 ° C. and a T-die temperature of 240 ° C. using a T-die type film melt-extrusion molding machine (T-die width 500 mm) equipped with 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. Each of the following additives was sufficiently dissolved with stirring and heating to prepare a dope. The solid content concentration of the dope was 21% by mass.

Acrylic resin (Delpet (registered trademark) 80N manufactured by Asahi Kasei Chemicals Co., Ltd.) 100 parts by mass,
UV absorber (Tinuvin (registered trademark) 477, manufactured by BASF Japan Ltd.) 5 parts by mass,
Organic solvent (methylene chloride: methanol: butanol = 79: 20: 1 (mass ratio)) 395 parts by mass.

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

[Acrylic resin film formation]
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 dope prepared above 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 is a metal support for casting. The amount of the dope supplied was set so that the thickness after the final drying was completed was 20 μm. Next, the dope supplied on the endless belt was dried with a drying air at 40 ° C. to form a film (web), and then peeled off from the endless belt. Then, 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 keeping the intervals at the same intervals. After removing the pins, the web was further dried at 130 ° C. At this time, the drying time was appropriately adjusted to set the residual solvent amount to 5% by mass. Subsequently, the web is slit to a width of 1 m, and then zone stretching is performed 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). The web was dried at a drying temperature of 135 ° C. After stretching the tenter, the web was subjected to a relaxation treatment at 130 ° C. for 5 minutes, and then the drying of the web was completed while transporting the drying zones at 120 ° C. and 140 ° C. with a large number of rolls. Then, the dried web is slit to a width of 1.0 m, both ends of the film are knurled with a width of 10 mm and a height of 5 μm, and then wound around a core to produce a stretched acrylic resin film A1. did.

<Manufacturing of polarizing plate>
[Manufacturing of modulator]
A long polyvinyl alcohol film (trade name: Kuraray Vinylon PE3000 manufactured by Kuraray Co., Ltd.) with 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 the original film, as shown below. 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 original film was immersed in a swelling tank containing pure water at 37 ° C. for 80 seconds while maintaining a tense state in the transport direction (flow direction) so as not to loosen, to sufficiently swell the film. The roll speed ratio between the inlet and outlet of the swelling tank due to 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 draw ratio in the transport direction of the film in the water immersion tank was 1.04 times. Next, uniaxial stretching was performed at a draw ratio of about 1.6 times while immersing the film in a dyeing tank containing an aqueous solution containing iodine / potassium iodide / water in a weight ratio of 0.04 / 1.5 / 100. .. Then, the first boric acid is immersed in a first boric acid tank containing an aqueous solution of potassium iodide / boric acid / water in a weight ratio of 12 / 3.6 / 100 at a temperature of 56.5 ° C. for 130 seconds. While undergoing the treatment, uniaxial stretching was performed until the cumulative stretching ratio from the original fabric became 5.3 times. Further, the second boric acid treatment is performed by immersing the potassium iodide / boric acid / water in a second boric acid tank containing an aqueous solution having a weight ratio of 12 / 1.5 / 100 at a temperature of 30 ° C. for 60 seconds. rice field. Subsequently, after immersing in a water washing tank containing pure water at 10 ° C for about 16 seconds to wash, the drying furnace at about 60 ° C and the drying furnace at about 85 ° C are passed through in sequence, and the residence time in these drying furnaces is totaled. Drying was performed for 160 seconds. In this way, a polarizing element having a thickness of 12 μm in which iodine was adsorbed and oriented was obtained.

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

Here, the slow axis of the polyester resin films P1 to 3 was a direction perpendicular to the long direction of the film (corresponding to the MD direction and the conveying direction) (corresponding to the TD direction and the width direction). The slow-phase axes of the cycloolefin resin films C1-5, C7, C9 and C10 were in the direction perpendicular to the elongated direction of the film. The slow axis of the cycloolefin resin film C6 was 45 ° with respect to the length direction of the film. The cycloolefin resin film C8 did not have a clear slow axis in the film surface. The slow axis of the acrylic resin film A1 was a direction parallel to the long direction of the film. Further, the absorption axis direction of the splitter was a direction parallel to the long direction of the splitter.

The molecular weights shown in Table 1 below are values calculated from the total atomic weights of ultraviolet absorbers other than the polymer-type ultraviolet absorbers. 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. As for the molecular weight of the polymer type ultraviolet absorber, the 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,
Device name TOSOH HLC-8220GPC,
Three columns TOSOH TSKgel Super HZM-H (4.6 mm x 15 cm) were connected and used.
Column temperature 25 ° C,
Sample concentration 0.1% by mass,
Flow velocity 0.35 ml / min,
Calibration curve A calibration curve with 7 samples from TOSOH standard polystyrene Mw = 2800000 to 1050 was used.

<Evaluation of polarizing plate>
(Evaluation of irregular punching property)
An adhesive layer and a release film were laminated on one side of each of the polarizing plates obtained above. Next, the obtained polarizing plate with an adhesive was punched into a deformed shape with a blade in the shape of an in-vehicle meter shown in FIG. 1 and cut. 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. Further, the concave curved portion at the upper part of the vehicle-mounted 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.

Then, the release film was peeled off from the polarizing plate cut by punching out a deformed shape, and the adhesive side thereof was attached to a glass substrate for a liquid crystal cell manufactured by Corning. Ten such samples were prepared for each polarizing plate. In this state, it was first confirmed with an optical microscope whether or not the transducer was broken, and the number of samples in which cracks were generated was counted. Based on the following evaluation criteria, the deformed punching property was evaluated from the number of cracked polarizing plates. As a result of the evaluation, if it was Δ or higher, it was judged that there was no problem in practical use.

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

(Evaluation of adhesiveness after heat resistance test)
Each polarizing plate obtained above was stored in a constant temperature bath at 90 ° C. for 100 hours, and then left to stand in an environment of 23 ° C. and 55% RH for 24 hours. Next, when the adhesive surface between the polarizing element of the polarizing plate and the cycloolefin resin film or the acrylic resin film and the adhesive surface between the polarizing element of the polarizing plate and the polyester resin film are peeled off by hand, the material breaks in each film. The presence or absence of the occurrence of the film and the degree of peeling were visually observed, and the adhesiveness was evaluated according to the following evaluation criteria. In this evaluation, when the adhesive surface is peeled off by hand, if the adhesive force is strong, peeling does not occur, and if the adhesive force is weak, the material does not break at the interface between the film and the polarizing element, and peeling occurs. If the adhesive strength is between these, material breakage occurs at the interface between the film and the stator. As a result of the evaluation, if it was Δ or higher, it was judged that there was no problem in practical use.

⊚: Cycloolefin resin film or acrylic resin film, and polyester resin film do not peel off together;
◯: With respect to the cycloolefin resin film, the acrylic resin film, and the polyester resin film, there is no problem in the adhesive force between the film and the polarizing element.
When trying to peel off the film, one of the following (i) and (ii) applies:
(I) One of these films does not peel off, causing material (base material) destruction in at least half of one end of the other film or stator.
(Ii) Material (base material) fracture occurs in at least half or more of at least one end of both of these films or stators;
Δ: For both the cycloolefin resin film, the acrylic resin film, and the polyester resin film, there is no problem in the adhesive force between the film and the polarizing element.
When an attempt is made to peel off the film, one of these films falls under any of the following (iii) to (v), and the other film or a stator is formed on at least half of one end of the film. Material (base material) destruction occurs:
(Iii) Does not peel off,
(Iv) Material (base material) fracture occurs in at least half of one end of the film or stator.
(V) Material (base material) fracture occurs in less than half of at least one end of the film or stator;
X: For the cycloolefin resin film, the acrylic resin film, and the polyester resin film, the adhesive force between at least one of the films and the polarizing element 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 substituent.

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

[Calculation of degree of polarization P0, P500 and amount of change in degree of polarization]
Degree of polarization P0 (%) = [(H0-H90) / (H0 + H90)] 1/2 × 100
Degree of polarization P500 (%) = [(H0'-H90') / (H0' + H90')] 1/2 x 100
Amount of change in degree of polarization (%) = P0-P500
As a result of evaluating the fading of the polarizing element, the polarizing plate No. In 1 to 19, 21 and 22, the amount of change in the degree of polarization is less than 10%, and the polarizing plate No. 20 and No. 23 confirmed that the amount of change in the degree of polarization was 25% or more. In addition, the polarizing plate No. In the comparison among 1 to 19, 21 and 22, the polarizing plate No. Polarizing plate No. 13 rather than 13. It was confirmed that the amount of change in the degree of polarization was smaller in 1 to 12, 14 to 19, 21 and 22.

(Light leakage evaluation)
Using each of the polarizing plates obtained above, a liquid crystal display device was produced according to the following method. First, as liquid crystal cells, IPS-type and VA-type liquid crystal cells having a glass substrate having a total thickness of 0.1 mm and a liquid crystal layer arranged between them were prepared. Next, each polarizing plate is placed on the absorption axis of the polarizing element of the polarizing plate on the viewing side and the back light side via an adhesive so that the cycloolefin resin film or acrylic resin film side of the polarizing plate is arranged on the liquid crystal cell side. A VA liquid crystal display device and an IPS liquid crystal display device having each polarizing plate were obtained by bonding to both sides of the liquid crystal cell so that the absorption axes of the polarizing elements of the polarizing plate were orthogonal to each other. Each liquid crystal display device 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 the four corners of the screen at the time of black display was visually observed.

As a result of the light leakage evaluation, the polarizing plate No. No light leakage was confirmed in 1 to 16, and the polarizing plate No. Light leakage was confirmed at 17-23.

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

(Evaluation result of polarizing plate)
From the results in Table 2, the polarizing plate according to the present invention and the polarizing plate No. according to the reference example . It was confirmed that 1 to 16 were excellent in both deformed punching property and adhesiveness after the heat resistance test.

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

Further, from the result of the evaluation of the fading of the polarizing element, the polarizing plate according to the present invention and the polarizing plate No. according to the reference example . It was confirmed that 1 to 16 had an excellent ability to block ultraviolet rays. On the other hand, the polarizing plate No. 20 and No. In No. 23, the amount of change in the degree of polarization became large. This is the polarizing plate No. 20 and No. In No. 23, since the hard coat layer and the polyester resin film do not contain an ultraviolet absorber, it is presumed that ultraviolet rays are transmitted from this surface to the polarizing element and the polarizing element is deteriorated.

Furthermore, the liquid crystal display device manufactured by the light leakage evaluation was left for a certain period of time under ultraviolet irradiation instead of being stored in an environment of 60 ° C. and 90% RH for 500 hours, and the same observation was performed in a dark room. Polarizing plate No. 20 and polarizing plate No. 20 Light leakage was confirmed only in the liquid crystal display device (VA liquid crystal display device, IPS liquid crystal display device) using 23. 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 23 was large. This is the polarizing plate No. 20 and No. In No. 23, since the hard coat layer and the polyester resin film do not contain an ultraviolet absorber, it is presumed that ultraviolet rays are transmitted from this surface to the polarizing element and the polarizing element is deteriorated. In addition, the polarizing plate No. Since the cycloolefin resin film does not contain an ultraviolet absorber, it is presumed that the ultraviolet rays are further transmitted to the liquid crystal cell and the liquid crystal cell is deteriorated in addition to the polarizing element.

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.

1 Polarizing plate 2 Hard coat layer 3 Polyester resin film 4 Easy-adhesion layer 5 Polarizer 6 Cycloolefin resin film.

Claims (11)

It has a laminated structure in which a hard coat layer, a polyester resin film, a polarizing element, and a cycloolefin resin film containing a cycloolefin polymer are laminated in this order.
The hard coat layer and the cycloolefin resin film contain an ultraviolet absorber, and the hard coat layer and the cycloolefin resin film contain an ultraviolet absorber.
The polyester resin film does not substantially contain an ultraviolet absorber and does not contain.
The ultraviolet absorber contained in the hard coat layer contains a benzotriazole-based compound having a molecular weight of 700 or more.
The ultraviolet absorber contained in the cycloolefin resin film contains a triazine-based compound having a molecular weight of 500 or more and less than 1000.
The hard coat layer contains the ionizing radiation type curable compound, and is contained in the cycloolefin resin film with respect to the content (parts by mass) of the ultraviolet absorber with respect to 100 parts by mass of the cycloolefin polymer . The ratio of the content (parts by mass) of the ultraviolet absorber to 100 parts by mass of the ionized radiation curable compound contained in the hard coat layer is 0.1 or more and 0.7 or less.
The ratio of the thickness (μm) of the hard coat layer to the thickness (μm) of the cycloolefin resin film is 0.05 or more and 0.4 or less.
The cycloolefin resin film is a solution casting film.
Polarizer. It has a laminated structure in which a hard coat layer, a polyester resin film, a polarizing element, and a cycloolefin resin film containing a cycloolefin polymer are laminated in this order.
The hard coat layer and the cycloolefin resin film contain an ultraviolet absorber, and the hard coat layer and the cycloolefin resin film contain an ultraviolet absorber.
The polyester resin film does not substantially contain an ultraviolet absorber and does not contain.
The ultraviolet absorber contained in the hard coat layer contains a benzotriazole-based compound having a molecular weight of 700 or more.
The ultraviolet absorber contained in the cycloolefin resin film contains a triazine-based compound having a molecular weight of 500 or more and less than 1000.
The hard coat layer contains an ionizing radiation type curable compound, and the hard coat layer is contained in the cycloolefin resin film with respect to the content (parts by mass) of the ultraviolet absorber with respect to 100 parts by mass of the cycloolefin polymer. The ratio of the content (parts by mass) of the ultraviolet absorber to 100 parts by mass of the ionized radiation curable compound contained in the above is 0.1 or more and 0.7 or less.
The ratio of the thickness (μm) of the hard coat layer to the thickness (μm) of the cycloolefin resin film is 0.05 or more and 0.4 or less.
The cycloolefin resin film is a solution casting film and is
The cycloolefin polymer is a (co) polymer obtained by polymerizing a cycloolefin monomer represented by the following general formula (5), or a hydride obtained by hydrogenating the (co) polymer. contains:

In the ceremony, R ¹⁶ And R ¹⁸ Are independently substituted with 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, a polar group, or a polar group. And R ¹⁶ And R ¹⁸ May be bonded to each other to form an unsaturated bond, monocyclic or polycyclic, which monocyclic or polycyclic may have a double bond or may form an aromatic ring. ,
R ¹⁷ And R ¹⁹ One is a hydrogen atom and the other is a polar group.
p and m are each independently an integer of 0 or more.
Polarizer. It has a laminated structure in which a hard coat layer, a polyester resin film, a polarizing element, and a cycloolefin resin film containing a cycloolefin polymer are laminated in this order.
The hard coat layer and the cycloolefin resin film contain an ultraviolet absorber, and the hard coat layer and the cycloolefin resin film contain an ultraviolet absorber.
The polyester resin film does not substantially contain an ultraviolet absorber and does not contain.
The ultraviolet absorber contained in the hard coat layer contains a benzotriazole-based compound having a molecular weight of 700 or more.
The ultraviolet absorber contained in the cycloolefin resin film contains a triazine-based compound having a molecular weight of 500 or more and less than 1000.
The hard coat layer contains an ionizing radiation type curable compound, and the hard coat layer is contained in the cycloolefin resin film with respect to the content (parts by mass) of the ultraviolet absorber with respect to 100 parts by mass of the cycloolefin polymer. The ratio of the content (parts by mass) of the ultraviolet absorber to 100 parts by mass of the ionized radiation curable compound contained in the above is 0.1 or more and 0.7 or less.
The ratio of the thickness (μm) of the hard coat layer to the thickness (μm) of the cycloolefin resin film is 0.05 or more and 0.4 or less.
The cycloolefin polymer is a (co) polymer obtained by polymerizing a cycloolefin monomer represented by the following general formula (5), or a hydride obtained by hydrogenating the (co) polymer. contains:

In the ceremony, R ¹⁶ And R ¹⁸ Are independently substituted with 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, a polar group, or a polar group. And R ¹⁶ And R ¹⁸ May be bonded to each other to form an unsaturated bond, monocyclic or polycyclic, which monocyclic or polycyclic may have a double bond or may form an aromatic ring. ,
R ¹⁷ And R ¹⁹ One is a hydrogen atom and the other is a polar group.
p and m are each independently an integer of 0 or more.
Polarizer. The polarizing plate according to any one of claims 1 to 3, wherein the cycloolefin polymer contains a cycloolefin polymer having a partial structure derived from the following general formula (6):

In the ceremony, R ¹⁸ Is 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, a polar group, or a hydrocarbon group substituted with a polar group.
R ¹⁹ Is a polar group. It has a laminated structure in which a hard coat layer, a polyester resin film, a polarizing element, and an acrylic resin film containing a (meth) acrylic polymer are laminated in this order.
The hard coat layer and the acrylic resin film contain an ultraviolet absorber, and the hard coat layer and the acrylic resin film contain an ultraviolet absorber.
The polyester resin film does not substantially contain an ultraviolet absorber and does not contain.
The ultraviolet absorber contained in the hard coat layer contains a benzotriazole-based compound having a molecular weight of 700 or more.
The ultraviolet absorber contained in the acrylic resin film contains a triazine-based compound having a molecular weight of 500 or more and less than 1000.
The hard coat layer contains the ionizing radiation type curable compound, and the hard coat is contained in the acrylic resin film with respect to the content (parts by mass) of the ultraviolet absorber with respect to 100 parts by mass of the (meth) acrylic polymer. The ratio of the content (parts by mass) of the ultraviolet absorber to 100 parts by mass of the ionized radiation curable compound contained in the layer is 0.1 or more and 0.7 or less.
The ratio of the thickness (μm) of the hard coat layer to the thickness (μm) of the acrylic resin film is 0.05 or more and 0.4 or less.
Polarizer. The polarizing plate according to claim 5, wherein the acrylic resin film is a solution casting film. The triazine-based compound, which is the ultraviolet absorber contained in the cycloolefin resin film or the acrylic resin film, contains a compound having one triazine skeleton in the molecule, any one of claims 1 to 6. The polarizing plate according to. The one according to any one of claims 1 to 7 , wherein 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. Plate plate. One of claims 1 to 8 , wherein the content of the ultraviolet absorber with respect to 100 parts by mass of the ionizing radiation curable compound contained in the hard coat layer is 0.1 part by mass or more and 3 parts by mass or less. The polarizing plate according to. The polarizing plate according to any one of claims 1 to 9 , wherein the hard coat layer has a film thickness of 2 μm or more and 5 μm or less. A display device comprising the polarizing plate according to any one of claims 1 to 10 .

Images