Polarizing film, laminated polarizing film, image display panel, and image display device

Abstract

To provide a polarizing film which offers a superior property to suppress reduction in single transmittance in high-temperature environments.SOLUTION: A polarizing film constituting an image display device having an image display cell is provided, the polarizing film comprising a polarizing membrane, a functional layer, an adhesive layer, and a first transparent protective film. The functional layer is disposed next to the polarizing membrane on the image display cell side and contains a water-soluble radical scavenger, and the first transparent protective film is provided on the functional layer with the adhesive layer in between.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a polarizing film, a laminated polarizing film, an image display panel, and an image display device. Regarding. [Background technology]

[0002] Conventionally, polarizing films used in various image display devices such as liquid crystal display devices and organic EL display devices have been It has high transmittance and high polarization, and is dyed (using iodine or dichroic dyes). A polyvinyl alcohol film containing a dichroic material such as The light film is a polyvinyl alcohol film that is subjected to various processes such as swelling, dyeing, crosslinking, and stretching in a bath. After the various processes such as stretching, washing is carried out and then drying is carried out. The polarizing film is usually provided with a protective film such as triacetyl cellulose on one or both sides thereof. These are used as polarizing films (polarizing plates) by bonding them together using adhesive.

[0003] The various image display devices described above usually comprise an image display cell such as a liquid crystal cell or an organic EL element, and a a viewing-side polarizing film disposed on the viewing side of the image display cell; and a rear-side polarizing film arranged on the backlight side (patent document 1-2). If necessary, the polarizing film may be laminated with other optical layers to form a laminated polarizing film (optical and further, the polarizing film or the laminated polarizing film ( The optical laminate is used as an image display panel bonded to the image display cell. (Patent Document 3).

[0004] In recent years, various image display devices have been incorporated into mobile devices such as mobile phones and tablet terminals. In addition, it can also be used as an in-vehicle image display device such as a car navigation system or a back monitor. Accordingly, the polarizing film and the laminated polarizing film are becoming more and more widely used. Films are required to withstand harsher environments (e.g., high temperature environments) than previously required. High durability is required for polarized films, and the polarized film is designed to ensure such durability. Films and image display devices have been proposed (Patent Documents 4 and 5). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-227731 [Patent Document 2] Japanese Patent Application Laid-Open No. 2019-128430 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-102353 [Patent Document 4] Special Publication No. 2012-516468 [Patent Document 5] Japanese Patent Application Publication No. 2018-101117 Summary of the Invention [Problem to be solved by the invention]

[0006] With the recent development of autonomous driving technology, the display devices mentioned above are becoming increasingly The designs are becoming increasingly larger and more unusual. There is a demand for a way to further improve the durability of polarizing films in high-temperature environments. There are.

[0007] In view of the above circumstances, the present invention provides a method for suppressing the decrease in the single-piece transmittance in a high-temperature environment. The object of the present invention is to provide a polarizing film that is excellent in:

[0008] The present invention also relates to a laminated polarizing film, an image display panel, and a polarizing film using the polarizing film. and an image display device. [Means for solving the problem]

[0009] That is, the present invention is a polarizing film that constitutes an image display device having an image display cell. The polarizing film includes a polarizing film, a functional layer, an adhesive layer, and a first transparent protective film. the functional layer is adjacent to the polarizing film on the image display cell side, and The first transparent protective film contains a scavenger, and is attached to the functional layer via an adhesive layer. This relates to polarizing films that are used in

[0010] The present invention also relates to a laminated polarizing film in which the polarizing film is bonded to an optical layer. Regarding.

[0011] The present invention also provides an image display cell and the polarizing film or the laminated polarizing film. The present invention relates to an image display panel having the same.

[0012] The present invention also relates to an image display device having the image display panel and a front transparent member. . [Effects of the Invention]

[0013] Although the details of the mechanism of action of the polarizing film of the present invention are unclear, the following It is presumed as follows. However, the present invention is not limited to this mechanism of action. .

[0014] The polarizing film of the present invention is a polarizing film that constitutes an image display device having an image display cell. The polarizing film includes a polarizing film, a functional layer, an adhesive layer, and a first transparent protective film. the functional layer is adjacent to the polarizing film on the image display cell side, and The first transparent protective film contains a radical scavenger, and the first transparent protective film is attached to the functional layer via an adhesive layer. Usually, the image display cell side of the polarizing film constituting the image display device is heated. Sometimes, the moisture in the polarizing film is difficult to release outside the system, and the remaining moisture can cause deterioration of the polarizing film. It is estimated that the reduction in the single-unit permeability (polyenation) occurs due to the promotion of the The bright polarizing film is a water-soluble radiative barrier film contained in a functional layer adjacent to the cell side of the polarizing film. The scavenger agent is easily transferred to the moisture in the polarizing film, and the lanthanum that may be generated by the progress of polyenation is removed. Since it can capture radicals, it prevents the decrease in the single transmittance from the cell side of the polarizing film (polyenation). Since the reduction can be efficiently suppressed, the reduction in the single-piece transmittance in a high-temperature environment is effectively suppressed. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic cross-sectional view showing one embodiment of an image display device. [Figure 2] FIG. 2 is a schematic cross-sectional view showing one embodiment of a polarizing film (viewer-side polarizing film). [Figure 3] FIG. 2 is a schematic cross-sectional view showing one embodiment of a polarizing film (viewer-side polarizing film). [Figure 4] FIG. 2 is a schematic cross-sectional view showing one embodiment of a polarizing film (rear-side polarizing film). [Figure 5] FIG. 2 is a schematic cross-sectional view showing one embodiment of a polarizing film (rear-side polarizing film). DETAILED DESCRIPTION OF THE INVENTION

[0016] FIG. 1 is a schematic cross-sectional view showing one embodiment of the image display device of the present invention. The display cell 90 is an image display cell of the polarizing film of the polarizing film (viewing side polarizing film) 10(a). 1. An embodiment of an image display panel in which the two sides are bonded together via a pressure-sensitive adhesive layer or adhesive layer 50. 1, the image display cell 90 is provided with a polarizing film (rear polarizing film) 10. The image display cell side of the polarizing film of (b) is bonded via a pressure sensitive adhesive layer or adhesive layer 60. FIG. 1 shows an embodiment of an image display panel in which a polarizing film ( The image display device 100 has a front transparent member 80 on the viewing-side polarizing film 10(a) side. The polarizing film (rear-side polarizing film) 10(b) is an example of a polarizing film. A backlight unit (not shown) is disposed on the opposite side to the display cell side.

[0017] FIG. 2 is a schematic cross-sectional view showing one embodiment of the polarizing film (viewer-side polarizing film) of the present invention. In FIG. 1, the functional layer 12 is adjacent to the polarizing film 11 on the image display cell side, and The polarizing film 13 is attached to the functional layer 12 via the adhesive layer 20. 10(a) shows one embodiment of the system 10.

[0018] FIG. 3 is a schematic cross-sectional view showing one embodiment of the polarizing film (viewer-side polarizing film) of the present invention. In FIG. 3, the functional layer 12 is adjacent to the polarizing film 11 on the image display cell side, and The transparent protective film 13 is provided on the functional layer 12 via an adhesive layer 20, and further On the opposite side (viewing side) of the polarizing film 11 to the image display cell side, a pressure sensitive adhesive layer or adhesive layer 30 is provided. 1 shows an embodiment of a polarizing film 10(a) in which a second transparent protective film 14 is provided. .

[0019] FIG. 4 is a schematic cross-sectional view showing one embodiment of the polarizing film (rear-side polarizing film) of the present invention. In FIG. 4, the functional layer 12 is adjacent to the polarizing film 11 on the image display cell side, and the first transparent The polarizing film 13 is attached to the functional layer 12 via the adhesive layer 20. 10(b) shows one embodiment of the method.

[0020] FIG. 5 is a schematic cross-sectional view showing one embodiment of the polarizing film (rear-side polarizing film) of the present invention. In FIG. 5, the functional layer 12 is adjacent to the polarizing film 11 on the image display cell side, and the first transparent The transparent protective film 13 is provided on the functional layer 12 via an adhesive layer 20, and further An adhesive layer or adhesive layer 3 is formed on the opposite side (backlight side) of the polarizing film 11 to the image display cell side. 1. A polarizing film 10(b) having a second transparent protective film 14 provided thereon via a polarizing film 10(b). Shows the state.

[0021] <Polarizing film> The polarizing film of the present invention is a polarizing film that constitutes an image display device having an image display cell. The polarizing film includes a polarizing film, a functional layer, an adhesive layer, and a first transparent protective film. the functional layer is adjacent to the polarizing film on the image display cell side, and The first transparent protective film contains a radical scavenger, and the first transparent protective film is attached to the functional layer via an adhesive layer. The polarizing film is a viewer-side polarizing film disposed on the viewer side of the image display cell. A film and a rear polarizer disposed on the opposite side (backlight side) of the image display cell from the viewing side. The polarizing film on the viewing side and the polarizing film on the rear side may be either a polarizing film or a polarizing film. may be the same or different.

[0022] <Polarizing film> The polarizing film of the present invention is a film containing a dichroic dye such as iodine or a dichroic dye in a polyvinyl alcohol film. From the viewpoint of the initial polarization performance of the polarizing film, the dichroic material and Of these, iodine is preferred.

[0023] The polyvinyl alcohol (PVA) film has transparency in the visible light region. Any material that disperses and adsorbs dichroic substances such as iodine and dichroic dyes can be used without any particular limitations. In addition, the PVA film that is usually used as the raw material has a thickness of about 1 to 100 μm. It is preferable that the thickness is about 1 to 50 μm, and more preferable that the width is 100 to 5000 mm. It is preferable that the degree of

[0024] The material for the polyvinyl alcohol film is polyvinyl alcohol or its Examples of the derivatives of polyvinyl alcohol include polyvinyl alcohol. formal, polyvinyl acetal; olefins such as ethylene and propylene; acrylic unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and their alkyl esters, The polyvinyl alcohol may be modified with acrylamide or the like. The degree is preferably about 100 to 10,000, and about 1,000 to 10,000. It is more preferable that the molecular weight is about 1,500 to 4,500, and even more preferable that the molecular weight is about 1,500 to 4,500. The polyvinyl alcohol preferably has a saponification degree of about 80 to 100 mol %. It is preferable that the average polymerization ratio is about 95 mol % to 99.95 mol. The degree of saponification and the degree of saponification can be determined in accordance with JIS K 6726.

[0025] The polyvinyl alcohol film contains additives such as a plasticizer and a surfactant. Examples of the plasticizer include glycerin, diglycerin, and triglycerin. polyols such as ethylene glycol, propylene glycol, and polyethylene glycol; The amount of the additives used is not particularly limited. The content of the polyvinyl alcohol film is preferably about 20% by weight or less.

[0026] The polarizing film may be formed by, for example, dissolving the polyvinyl alcohol film in a solvent such as iodine or a dichroic dye. The fabric is dyed by immersing it in an aqueous solution of the dichroic substance and stretched to 3 to 7 times its original length. If necessary, it can be immersed in an aqueous solution of boric acid or potassium iodide. Furthermore, if necessary, the polyvinyl alcohol film can be immersed in water before dyeing. The polyvinyl alcohol film may be washed with water. It can clean dirt and anti-blocking agents from the surface of vinyl films, and also removes stains from polyvinyl chloride films. Swelling the vinyl alcohol film also has the effect of preventing unevenness such as uneven dyeing. The stretching may be carried out after dyeing with iodine, or may be carried out while dyeing. After stretching, the fabric may be dyed with iodine. In an aqueous solution of boric acid or potassium iodide, or in a water bath, can also be stretched.

[0027] The polarizing film has a thickness of 1 μm or more from the viewpoint of improving the initial polarization degree of the polarizing film. It is preferable that the thickness is 2 μm or more, and more preferable that the thickness is 2 μm or more, and it is ... From this viewpoint, the thickness is preferably 15 μm or less, and more preferably 10 μm or less. It is more preferable that the thickness is 8 μm or less. In particular, a polarizing film having a thickness of about 8 μm or less is In order to obtain the above-mentioned polyvinyl alcohol film, a film is formed on a thermoplastic resin substrate. The following thin polarizing film is manufactured using a laminate containing the polyvinyl alcohol-based resin layer: The method can be applied.

[0028] <Method for manufacturing thin polarizing film> The method for manufacturing a thin polarizing film is to attach a polyvinyl alcohol film to one side of a long thermoplastic resin substrate. A polyvinyl alcohol resin layer (PVA resin layer) containing a vinyl resin (PVA resin) is formed. The laminate is then subjected to an air-assisted stretching treatment, a dyeing treatment, and an underwater stretching treatment. This involves carrying out stretching treatment and drying shrinkage treatment in this order. To obtain a polarizing film, the film is stretched in air (dry stretching) and then stretched in water in a boric acid solution. A two-stage drawing method is selected to combine the processes.

[0029] As a method for producing the laminate, any appropriate method can be adopted, and for example, The method comprises applying a coating liquid containing the PVA resin to the surface of a plastic resin substrate and drying the coating liquid. The thickness of the thermoplastic resin substrate is preferably about 20 to 300 μm. The thickness of the PVA-based resin layer is preferably about 50 to 200 μm. It is preferably about 100 μm or less, and more preferably about 3 to 20 μm.

[0030] The thermoplastic resin substrate absorbs water to significantly reduce the stretching stress, allowing it to be stretched at a high ratio. From the viewpoint of being able to do so, the water absorption rate is preferably about 0.2% or more, and more preferably about 0.3%. On the other hand, the thermoplastic resin substrate is preferably a thermoplastic resin substrate having a size of 100 mm or more. This prevents problems such as a significant decrease in process stability and a deterioration in the appearance of the resulting polarizing film. From the viewpoint of being able to do so, the water absorption rate is preferably about 3% or less, and more preferably about 1% or less. It is more preferable that the water absorption rate is, for example, The water absorption rate can be adjusted by introducing a modifying group. This is the value calculated in accordance with 9.

[0031] The thermoplastic resin substrate is a material that suppresses crystallization of the PVA-based resin layer while improving the stretchability of the laminate. From the viewpoint of ensuring sufficient strength, the glass transition temperature (Tg) is set to about 120°C or less. Furthermore, it is preferable to perform the plasticization of the thermoplastic resin substrate by water and the underwater stretching well. Considering this, it is more preferable that the glass transition temperature (Tg) is about 100°C or less. On the other hand, the glass of the thermoplastic resin substrate is The transition temperature is the temperature at which defects such as deformation of the thermoplastic resin substrate occur when the coating liquid is applied and dried. To prevent this and to produce a good laminate, the temperature should be about 60°C or higher. The glass transition temperature is preferably determined by, for example, the constituent material of the thermoplastic resin substrate. It can be adjusted by introducing a modifying group or by heating using a crystallizing material. The glass transition temperature (Tg) is a value determined in accordance with JIS K 7121.

[0032] Any appropriate thermoplastic resin can be used as the constituent material of the thermoplastic resin substrate. Examples of the thermoplastic resin include esters such as polyethylene terephthalate resins. olefin resins such as norbornene resins, olefin resins such as polypropylene Examples of the resins include acrylic resins, polyamide resins, polycarbonate resins, and copolymer resins thereof. Among these, norbornene resins and amorphous polyethylene terephthalate are The thermoplastic resin substrate is preferably a tungsten-based resin, and has excellent stretchability. From the viewpoint that crystallization during stretching can be suppressed, amorphous (non-crystalline) polyethylene terephthalate Amorphous (non-crystalline) polyethylene terephthalate resins are preferably used. As the dicarboxylic acid, isophthalic acid and / or cyclohexanedicarboxylic acid Copolymers containing cyclohexanedimethanol and diethylene glycol as glycols Examples of copolymers include copolymers containing ethylene glycol.

[0033] The thermoplastic resin substrate is subjected to a surface treatment (for example, corona treatment) before forming the PVA-based resin layer. Alternatively, an easy-adhesion layer may be formed on the thermoplastic resin substrate. By carrying out such treatment, it is possible to improve the adhesion between the thermoplastic resin substrate and the PVA-based resin layer. The thermoplastic resin substrate may be stretched before the PVA resin layer is formed. It may be possible.

[0034] The coating liquid is a solution in which a PVA resin is dissolved in a solvent. Examples include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methyl ethylpyrrolidone, various glycols, polyhydric alcohols such as trimethylolpropane, Examples of the amine include amines such as ethylenediamine and diethylenetriamine, and water is preferred. The PVA resins of the coating liquid may be used alone or in combination of two or more. The oil concentration is determined from the viewpoint of forming a uniform coating film that adheres closely to the thermoplastic resin substrate. The amount is preferably about 3 to 20 parts by weight relative to 100 parts by weight of the solvent.

[0035] The coating solution contains a polyvinyl alcohol having a molecular orientation improved by stretching. It is preferable that a halide is blended. Any suitable halide may be employed, including, for example, iodide and sodium chloride. Examples of the iodide include potassium iodide, sodium iodide, and lithium iodide. The concentration of the halide in the coating solution is preferably P The amount is preferably about 5 to 20 parts by weight, and more preferably 10 to 100 parts by weight of the VA resin. It is more preferable that the amount is about 5 parts by weight.

[0036] The coating liquid may contain additives. Examples of suitable surfactants include plasticizers such as polyethylene glycol and glycerin; and surfactants such as nonionic surfactants. can be.

[0037] Any appropriate method can be used as the method for applying the coating liquid. Roll coating, spin coating, wire bar coating, dip coating, die coating Examples include the curtain coat method, spray coat method, and knife coat method (comma coat method, etc.). The drying temperature of the coating liquid is preferably about 50° C. or higher.

[0038] The in-air auxiliary stretching treatment can stretch the thermoplastic resin substrate while suppressing crystallization of the thermoplastic resin substrate. Therefore, the laminate can be stretched at a high ratio. The stretching may be performed by fixed end stretching (for example, a method of stretching using a tenter stretching machine) or by free end stretching. (For example, a method of uniaxially stretching the laminate by passing it between rolls with different peripheral speeds) is also acceptable, but this method is expensive. From the viewpoint of obtaining the desired optical properties, free-end stretching is preferred.

[0039] The stretching ratio in the auxiliary in-air stretching is preferably about 2 to 3.5 times. The in-air auxiliary stretching may be carried out in one stage or in multiple stages. The stretching ratio is the product of the stretching ratios at each stage.

[0040] The stretching temperature in the in-air auxiliary stretching depends on the material of the thermoplastic resin substrate, the stretching method, etc. It can be set to any appropriate value depending on the application, for example, the glass transition temperature of the thermoplastic resin substrate. It is preferable that the temperature is equal to or higher than the glass transition temperature (Tg), and the temperature is equal to or higher than the glass transition temperature (Tg) + 10°C. It is more preferable that the temperature is the glass transition temperature (Tg)+15°C or higher. On the other hand, the upper limit of the stretching temperature is set to suppress the rapid crystallization of the PVA resin and to prevent the crystallization. This prevents defects caused by stretching (for example, preventing the orientation of the PVA resin layer due to stretching). From the viewpoint of the feasibility of the heating, the temperature is preferably about 170°C.

[0041] If necessary, after the air-assisted stretching treatment and before the dyeing treatment or the underwater stretching treatment, the fiber may be subjected to an insolubilization treatment. The insolubilization treatment may be typically carried out by immersing the PVA-based resin layer in an aqueous boric acid solution. By performing the insolubilization treatment, water resistance is given to the PVA resin layer. This can prevent the orientation of PVA from decreasing when the film is immersed in water. The amount of the insolubilizing treatment bath is preferably about 1 to 5 parts by weight per 100 parts by weight of water. The liquid temperature is preferably about 20 to 50°C.

[0042] The dyeing treatment is carried out by dyeing the PVA-based resin layer with iodine. Examples of such methods include a method of immersing a PVA resin layer (laminate) in a dye solution containing iodine; A method of applying the dye solution to a VA-based resin layer, and a method of spraying the dye solution onto a PVA-based resin layer. and the like, and a method of immersing a PVA-based resin layer (laminate) in a dye solution containing iodine is preferred. It's nice.

[0043] The amount of iodine in the dye bath is 0.05 to 0.5 parts by weight per 100 parts by weight of water. In order to increase the solubility of iodine in water, an iodine aqueous solution is preferably used. The amount of the iodide to be added is preferably 100 parts by weight of water. It is preferably about 0.1 to 10 parts by weight, and more preferably about 0.3 to 5 parts by weight. The temperature of the dye bath is preferably 20 to 50°C in order to prevent dissolution of the PVA resin. The immersion time is preferably about 100 minutes from the viewpoint of ensuring the transmittance of the PVA-based resin layer. Therefore, it is preferably about 5 seconds to 5 minutes, and more preferably about 30 seconds to 90 seconds. In order to obtain a polarizing film having good optical properties, the iodine and The ratio of the content of iodide to the content of iodide is preferably about 1:5 to 1:20, and more preferably about 1:5 to 1: It is more preferable that it is about 10.

[0044] If necessary, a crosslinking treatment may be carried out after the dyeing treatment and before the underwater stretching treatment. The crosslinking treatment is typically carried out by immersing the PVA resin layer in an aqueous solution of boric acid. The cross-linking treatment gives the PVA resin layer water resistance, and the subsequent underwater stretching makes it possible to withstand high-temperature water. The boric acid in the aqueous solution of boric acid can prevent the orientation of the PVA from decreasing when the film is immersed in the aqueous solution of boric acid. The concentration is preferably about 1 to 5 parts by weight per 100 parts by weight of water. When the treatment is carried out, it is preferable to further add the above-mentioned iodide to the crosslinking bath in the crosslinking treatment. By blending the iodide, the elution of iodine adsorbed in the PVA-based resin layer is prevented. The amount of the iodide to be blended is 1 to 5 parts by weight per 100 parts by weight of water. The temperature of the crosslinking bath (boric acid aqueous solution) is about 20 to 50°C. It is preferable that there is.

[0045] The underwater stretching treatment is carried out by immersing the laminate in a stretching bath. The glass transition temperature of the thermoplastic resin substrate or PVA resin layer (typically around 80°C) It can be stretched at a low temperature, and the PVA resin layer can be stretched at a high magnification while suppressing its crystallization. The stretching method in the underwater stretching treatment can be fixed-end stretching (for example, using a tenter stretching machine). stretching using a roll having different peripheral speeds), or free end stretching (for example, laminating between rolls having different peripheral speeds) However, from the viewpoint of obtaining high optical properties, free end stretching is preferred. preferable.

[0046] The underwater stretching treatment is carried out by immersing the laminate in an aqueous boric acid solution (boric acid aqueous stretching By using a boric acid aqueous solution as the stretching bath, the PVA resin layer is It can provide the rigidity to withstand such tension and water resistance so that it does not dissolve in water. The concentration of boric acid in the solution is preferably 1 to 10 parts by weight per 100 parts by weight of water, It is more preferable that the content of the drawing bath (aqueous boric acid solution) is 2.5 to 6 parts by weight. Iodide may be added. The liquid temperature of the drawing bath is preferably about 40 to 85°C. The temperature is more preferably about 60 to 75° C. The immersion time of the laminate in the stretching bath is 15 seconds. It is preferable that the time is about 5 minutes.

[0047] The stretching ratio in the underwater stretching is preferably about 1.5 times or more, and more preferably about 3 times or more. More preferably, it is equal to or greater than this.

[0048] The total stretching ratio of the laminate is preferably about 5 times or more the original length of the laminate. It is preferable that the ratio is about 5.5 times or more.

[0049] The drying shrinkage treatment may be performed by zone heating, in which the entire zone is heated. This may be done by heating the roll (using a so-called heated roll), but it is preferable to By drying using a heated roll, the laminate can be efficiently processed. Heat curling can be suppressed to produce a polarizing film with excellent appearance, and the laminate can be kept flat. It dries while maintaining the condition, so it can prevent not only curls but also wrinkles. In addition, by shrinking the film in the width direction during the drying shrinkage treatment, the optical properties of the resulting polarizing film can be improved. From the viewpoint of improving the shrinkage property, the shrinkage rate in the width direction of the laminate due to the drying shrinkage treatment is It is preferably about 1 to 10%, and more preferably about 2 to 8%.

[0050] Heating temperature of the transport roll (temperature of the heating roll), number of heating rolls, contact time with the heating roll The drying conditions can be controlled by adjusting the heating roll temperature. The temperature is preferably about 0 to 120°C, and more preferably about 65 to 100°C. It is more preferable that the temperature is 70 to 80°C. From the viewpoint of effectively suppressing curling, the number of conveying rolls is usually about 2 to 40. The number of contact times between the laminate and the heating roll is preferably about 4 to 30. The time is preferably about 1 to 300 seconds, more preferably 1 to 20 seconds. It is more preferable that the time is 1 to 10 seconds.

[0051] The heating roll may be installed in a heating furnace or in a normal production line (at room temperature). Preferably, the drying device is installed in a heating oven equipped with a blower. By using hot air drying in combination, it is possible to suppress sudden temperature changes between the heating rolls. The temperature for hot air drying is about 30 to 100°C. The hot air drying time is preferably about 1 to 300 seconds. stomach.

[0052] After the underwater stretching treatment, it is preferable to carry out a washing treatment before the drying shrinkage treatment. The treatment is typically carried out by immersing the PVA resin layer in an aqueous potassium iodide solution. .

[0053] Furthermore, the dyeing treatment step, the underwater stretching treatment step, the insolubilization treatment step, and the crosslinking treatment step and each treatment bath in the cleaning treatment step contains a zinc salt, a pH adjuster, a pH buffer The zinc salt may contain additives such as other salts. zinc, zinc halides such as zinc iodide; inorganic zinc salts such as zinc sulfate and zinc acetate; Examples of the pH adjuster include strong acids such as hydrochloric acid, sulfuric acid, and nitric acid, and sodium hydroxide. Examples of the pH buffering agent include strong bases such as acetic acid, hydroxypropyl methyl acrylate, and potassium hydroxide. Carboxylic acids such as oxalic acid and citric acid and their salts, inorganic weak acids such as phosphoric acid and carbonic acid, Examples of the other salts include sodium chloride and potassium chloride. chlorides such as barium chloride, nitrates such as sodium nitrate and potassium nitrate, sodium sulfate Examples include sodium, sulfates such as potassium sulfate, and salts of alkali metals and alkaline earth metals. It can be obtained.

[0054] <Functional layer> The functional layer of the present invention is adjacent to the image display cell side of the polarizing film and is a water-soluble radical. Contains a scavenger.

[0055] The water-soluble radical scavenger is easily transferred to the water in the polarizing film, and is dissolved in 100 ml of water at 25°C. It is preferable that the compound is soluble in 1 part by weight or more of water at 25°C. It is more preferable that the compound be one that can dissolve 2 parts by weight or more in 00 parts by weight of the solvent. It is more preferable that the compound be soluble in 100 parts by weight of water in an amount of 5 parts by weight or more. The water-soluble radical scavengers may be used alone or in combination of two or more kinds.

[0056] The water-soluble radical scavenger is believed to be able to suppress polyenization of the polarizing film in a high-temperature environment. Examples of the water-soluble radical scavenger include hindered phenols, Standard amines, phosphorus, sulfur, benzotriazole, benzophenone, hydroxybenzoates Radical scavengers such as hydroxylamine, salicylic acid ester, and triazine compounds The water-soluble radical scavenger is a compound having the ability to scavenge radicals generated in the polarizing film. In terms of the radical species, for example, nitroxy radicals or radicals having a nitroxide group It is preferably a compound.

[0057] The nitroxy radical or the compound having a nitroxide group is From the viewpoint of having a relatively stable radical in the -N(-C)-O · Compounds having the formula (O · represents an oxy radical), and known Examples of N-oxyl compounds that can be used include those having an organic group with the following structure: Examples of compounds include: [ka] (In general formula (1), R 1 represents an oxy radical, R 2 From R 5 are independently hydrogen atoms or an alkyl group having 1 to 10 carbon atoms, and n represents 0 or 1. In general formula (1), the left side of the dotted line represents an optional organic group.

[0058] The compounds having the organic group include, for example, compounds represented by the following general formulas (2) to (5): Examples of compounds that can be used include: [ka] (In general formula (2), R 1 From R 5 , and n are the same as above, and R 6 is a hydrogen atom, or or an alkyl group, acyl group, or aryl group having 1 to 10 carbon atoms, and n is 0. or 1.) [ka] (In general formula (3), R 1 From R 5 , and n are the same as above, and R 7 and R 8 teeth, Independently, a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an acyl group, or an aryl group represents a aryl group.) [ka] (In general formula (4), R 1 From R 5 , and n are the same as above, and R 9 From R 11 teeth, independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an acyl group, an amino group, represents an alkoxy group, a hydroxy group, or an aryl group. [ka] (In general formula (5), R 1 From R 5 , and n are the same as above, and R 12 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an amino group, an alkoxy group, a hydroxy group, or an aryl group.

[0059] In the general formulas (1) to (5), R 2 From R 5 is a compound with a small number of carbon atoms from the viewpoint of availability. The alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. In addition, in the general formula (2), from the viewpoint of availability, R 6 is a hydrogen atom, Alternatively, it is preferably an alkyl group having 1 to 10 carbon atoms, and is preferably a hydrogen atom. In addition, in the general formula (3), from the viewpoint of availability, R 7 and R 8 is German Preferably, each alkyl group is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. In addition, in the general formula (4), from the viewpoint of availability, R 9 From R 11 is preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. In addition, in the general formula (5), from the viewpoint of availability, R 12 is a hydroxy group, In the general formulae (1) to (5), n is preferably an amino group or an alkoxy group. From the viewpoint of availability, 1 is preferred.

[0060] Furthermore, the N-oxyl compounds include those described in, for example, JP-A No. 2003-64022, JP 11-222462 A, JP 2002-284737 A, WO 2014 / 022462 A Examples of such compounds include the N-oxyl compounds described in US Pat. No. 16 / 047655.

[0061] In addition, examples of the compound having a nitroxy radical or a nitroxide group include Examples include the following compounds: [ka] (In the general formula (6), R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an acyl group. represents a group or an aryl group. [ka] [ka]

[0062] The water-soluble radical scavenger is used from the viewpoint of suppressing polyenization of the polarizing film in a high-temperature environment. Therefore, the molecular weight is preferably 1000 or less, and more preferably 500 or less. It is preferable that the ratio is 300 or less.

[0063] The content of the water-soluble radical scavenger in the functional layer is such that the content of the water-soluble radical scavenger is sufficient to suppress polyenization of the polarizing film. From this viewpoint, the content of the functional layer is preferably 0.1% by weight or more, and more preferably 5% by weight or more. It is more preferable that the content is 10% by weight or more, and it is further preferable that the content is 10% by weight or more. From the viewpoint of appearance after processing, it is preferable that the amount of the functional layer is 50% by weight or less, and 40% by weight or less. It is more preferably 10% by weight or less, and even more preferably 30% by weight or less.

[0064] The functional layer is made of a material that can form a layer such as a coating film. Any fat can be used without limitation, for example, polyvinyl alcohol resin, polyacrylic acid Among these, water-soluble plastic resins such as polyethylene terephthalate (PE) and polyethylene glycol (PE) are preferred because of their excellent adhesion to the polarizing film and durability. From the viewpoint of durability, polyvinyl alcohol resins are preferred. These may be used singly or in combination of two or more kinds.

[0065] The polyvinyl alcohol resin may be, for example, polyvinyl alcohol. Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. The polyvinyl alcohol resin may be, for example, a monomer copolymerizable with vinyl acetate. When the copolymerizable monomer is ethylene, a saponified copolymer of the copolymer and the ethylene may be used. In addition, an ethylene-vinyl alcohol copolymer can be obtained. Examples of the monomers include (anhydride) maleic acid, fumaric acid, crotonic acid, itaconic acid, ( Unsaturated carboxylic acids such as methacrylic acid and their esters; ethylene, propylene, etc. α-olefin, (meth)allylsulfonic acid (sodium), sulfonic acid sodium (monoal alkyl maleate), sodium disulfonate alkyl maleate, N-methylol acrylamide , acrylamidoalkylsulfonic acid alkali salt, N-vinylpyrrolidone, N-vinylpyrrolidone lolidone derivatives, etc. Furthermore, examples of the polyvinyl alcohol resin include For example, a modified polyvinyl alcohol or a copolymer thereof having a hydrophilic functional group in the side chain thereof Examples of the hydrophilic functional group include acetone, polyvinyl alcohol-based resins. In addition, modified polyvinyl alcohol resins and the like can be used. For example, polyvinyl alcohol resins are acetalized, urethane-modified, etherified, and graphitized. It may be esterified, phosphated, or the like.

[0066] The degree of saponification of the polyvinyl alcohol resin may be, for example, 88% or more. From the viewpoint of optical durability under high temperature and humidity, the saponification degree is preferably 90% or more. The degree of saponification is determined in accordance with JIS K 6726. It can be done.

[0067] the functional layer is formed from a resin composition containing the binder resin as a main component, For example, the proportion of the binder resin in the functional layer is preferably 70% by weight or more. It is preferable that the content is 80% by weight or more, and more preferable that the content is 90% by weight or more. Desirable.

[0068] The resin composition can be prepared as a solution by dissolving or dispersing the binder resin in a solvent. Examples of the solvent include water, dimethyl sulfoxide, and dimethylformamide. , dimethylacetamide, N-methylpyrrolidone, glycols, alcohols, ethylene Examples of the solvent include amines such as diamine and diethylenetriamine. Alternatively, two or more types may be used in combination.

[0069] The functional layer may contain, for example, a crosslinking agent, a plasticizer, a surfactant, a coupling agent, a tackifier, The composition may contain additives such as a heat stabilizer and a hydrolysis stabilizer.

[0070] The functional layer is formed by, for example, applying the resin composition to the polarizing film and drying it. The coating method is not particularly limited, and examples thereof include roll coating and spin coating. coating method, wire bar coating method, dip coating method, die coating method, curtain coating method, Examples of the method include a play coating method and a knife coating method.

[0071] The functional layer preferably has a thickness of 0.1 μm or more from the viewpoint of suppressing polyenization of the polarizing film. It is preferable that the thickness is 0.2 μm or more, and more preferable that the thickness is 0.5 μm or more. From the viewpoint of optical durability under high temperature and high humidity, it is preferable that the thickness is 10 μm or less. Preferably, the thickness is 5 μm or less, more preferably 2 μm or less, It is even more preferable that it is 1 μm or less.

[0072] The polarizing film has a first transparent protective film provided on the functional layer via an adhesive layer. The polarizing film has a second polarizing film on the side opposite to the image display cell side of the polarizing film. A transparent protective film may be provided.

[0073] <First and second transparent protective films> The first and second transparent protective films are not particularly limited and may be any of the films used in polarizing films. Various transparent protective films can be used. The material is, for example, excellent in transparency, mechanical strength, thermal stability, moisture blocking property, isotropy, etc. A thermoplastic resin is used. Examples of the thermoplastic resin include triacetyl cellulose. cellulose ester resins such as polyethylene terephthalate and polyethylene naphthalate polyester resins such as cellulose, polyethersulfone resins, polysulfone resins, Carbonate resins, polyamide resins such as nylon and aromatic polyamide, polyimide resins Resins, polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymers vinyl resins, (meth)acrylic resins, cyclic or norbornene-containing resins Polyolefin resin (norbornene resin), polyarylate resin, polystyrene resin Examples of the transparent resin include a polyvinyl alcohol resin and a mixture thereof. The bright protective film is (meth)acrylic, urethane, acrylic urethane, and epoxy. A hardened layer formed from a thermosetting resin such as a silicone resin or an ultraviolet-curable resin is used. Among these, cellulose ester resins, polycarbonate resins, (Meth)acrylic resins, cyclic polyolefin resins, and polyester resins are preferred. .

[0074] The thickness of the first and second transparent protective films can be determined appropriately, but generally, it is determined based on the strength. From the viewpoints of workability such as ease of handling and thin layer properties, the thickness is preferably about 1 to 500 μm. It is more preferable that the thickness is about 1 to 300 μm, and even more preferable that the thickness is about 5 to 100 μm. I wish.

[0075] When the first and second transparent protective films are attached to both sides of the polarizing film, The transparent protective films on both sides may be the same or different.

[0076] The transparent protective film has a front retardation of 40 nm or more and / or a thickness direction retardation of A retardation plate having a phase difference of 80 nm or more can be used. The thickness direction retardation is usually controlled in the range of 40 to 200 nm, and the thickness direction retardation is usually controlled in the range of 80 to 300 nm. When a retardation plate is used as the transparent protective film, the retardation plate is It also functions as a film, allowing for thinner designs.

[0077] The retardation plate may be, for example, a birefringent film made by uniaxially or biaxially stretching a polymer material. A film supporting the orientation layer of the liquid crystal polymer. The thickness of the retardation plate is not particularly limited, but is preferably about 20 to 150 μm. It is common practice to use the phase plate by pasting it onto a transparent protective film that does not have a phase difference. It may also be used.

[0078] The first and second transparent protective films may contain an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, or the like. any suitable additives such as a release agent, a color preventing agent, a flame retardant, an antistatic agent, a pigment, a colorant, etc. In particular, when the transparent protective film contains an ultraviolet absorber, the polarizing filter It can improve the light resistance of the film.

[0079] The first transparent protective film is preferably made of a transparent material from the viewpoint of production efficiency in the drying process after lamination. Humidity is 300g / (m 2 24h) or less, and 200g / (m 2 ·twenty four It is more preferable that the second transparent protective film is resistant to high temperature and high humidity of the polarizing plate. From the viewpoint of durability, moisture permeability is 100g / (m 2 24 hours or more is preferable. , 200g / (m 2 It is more preferable that the moisture permeability is 100 0g / (m 2 24h) or less, and 600g / (m 2 24 hours or less It is more preferable that the moisture permeability is measured by the moisture permeability test (C) of JIS Z0208. According to the method of the 1990s, a sample cut to a diameter of 60 mm was placed in approximately 15 g of calcium chloride. Place in a moisture permeable cup, place in a thermostatic chamber at 40°C and 90% RH, and leave for 24 hours. It can be calculated by measuring the weight increase of calcium chloride before and after the treatment.

[0080] The surfaces of the first and second transparent protective films that are not to be laminated with the polarizing film are coated with a hard coat. Other layers such as a protective layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer may be provided. The hard coat layer, anti-reflection layer, anti-sticking layer, and diffusion layer can be formed on the substrate. Other layers such as a diffusion layer or an anti-glare layer can be provided on the protective film itself, It may also be provided as a separate body from the protective film.

[0081] The functional layer and the first transparent protective film are bonded together via an adhesive layer. the polarizing film and the second transparent protective film, the first and second transparent protective films, The other layer, or the polarizing film and the other layer, are usually bonded via a pressure-sensitive adhesive layer or an adhesive layer. and glued together.

[0082] The adhesive for forming the adhesive layer may be any of various adhesives used in polarizing films. Examples of adhesives that can be used include rubber adhesives, acrylic adhesives, silicone adhesives, and urethane adhesives. vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl Examples include polyisoprene adhesives, polyacrylamide adhesives, and cellulose adhesives. Among these, acrylic adhesives are preferred.

[0083] The adhesive layer may be formed, for example, by applying the adhesive to a separator or the like that has been subjected to a release treatment. a method of applying the adhesive layer to a polarizing film or the like by coating and drying the adhesive layer to form the adhesive layer, and then transferring the adhesive layer to a polarizing film or the like; The adhesive layer may be formed by applying the adhesive to a polarizing film or the like and drying the applied adhesive. The thickness is not particularly limited, and is, for example, about 1 to 100 μm, or about 2 to 50 μm. It is preferable.

[0084] The adhesive for forming the adhesive layer may be any of various adhesives used in polarizing films. For example, an isocyanate adhesive, a polyvinyl alcohol adhesive, a gelatin adhesive, etc. These adhesives include vinyl-based adhesives, vinyl-based latex adhesives, and water-based polyester adhesives. It is usually used as an adhesive consisting of an aqueous solution (water-based adhesive), and contains 0.5 to 60% by weight of solids. Among these, polyvinyl alcohol adhesives are preferred, and acetone adhesives are also preferred. A triacetyl group-containing polyvinyl alcohol adhesive is more preferable. The adhesive for bonding the first transparent protective film is an adhesive that adheres the functional layer and the polarizing film to the first transparent protective film. From the viewpoint of adhesion, a water-based adhesive is preferred.

[0085] The water-based adhesive may contain a crosslinking agent. The crosslinking agent is usually a crosslinking agent used to crosslink the adhesive. A compound having at least two functional groups in one molecule that are reactive with the constituent polymers, etc. Compounds such as alkylenediamines, isocyanates, epoxies, and alkane compounds are used. Dehydes: amino-formaldehydes such as methylol urea and methylol melamine. The amount of crosslinking agent in the adhesive is 100 parts by weight of the polymer and other components that make up the adhesive. It is usually about 10 to 60 parts by weight.

[0086] In addition to the above, the adhesive may be an active element such as an ultraviolet curing adhesive or an electron beam curing adhesive. Examples of the active energy ray curable adhesive include: For example, a (meth)acrylate adhesive can be mentioned. Examples of the curable component in Examples of the compound having a (meth)acryloyl group include compounds having a (meth)acryloyl group. For example, a chain alkyl (meth)acrylate having 1 to 20 carbon atoms, an alicyclic alkyl (meth)acrylate, alkyl (meth)acrylates such as acrylates and polycyclic alkyl (meth)acrylates; Hydroxyl group-containing (meth)acrylates; epoxies such as glycidyl (meth)acrylate (Meth)acrylate adhesives include hydroxyl group-containing (meth)acrylates. N-methylol (meth)acrylamide, N-methylol (meth)acrylamide, N-ethoxymethyl(meth)acrylamide, N-ethoxymethyl(meth)acrylamide, Contains nitrogen-containing monomers such as (meth)acrylamide and (meth)acryloylmorpholine The (meth)acrylate adhesive may contain tripropylene glycol as a crosslinking component. Diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethacrylate Nol diacrylate, cyclic trimethylolpropane formal acrylate, dioxane Multifunctional monoacrylates such as ethylene glycol diacrylate and EO-modified diglycerin tetraacrylate In addition, the cationic polymerization curing adhesive may contain an epoxy group or an oxetane group. Compounds having an aryl group can also be used. Compounds having an epoxy group can also be used. There are no particular limitations on the epoxy group as long as it has at least two epoxy groups. A variety of curable epoxy compounds can be used.

[0087] The adhesive may contain appropriate additives as needed. Examples of the additives include: For example, coupling agents such as silane coupling agents and titanium coupling agents, ethylene oxide Adhesion promoters such as oxides, UV absorbers, anti-degradation agents, dyes, processing aids, ion trapping agents , antioxidants, tackifiers, fillers, plasticizers, leveling agents, foam inhibitors, antistatic agents, Examples of the stabilizers include heat-resistant stabilizers and hydrolysis-resistant stabilizers.

[0088] The adhesive is applied to the functional layer side, the first and second transparent protective film sides (or The bonding may be performed on either the side of the other layer or the side of the polarizing film, or may be performed on both sides. After the bonding, a drying step is carried out to form an adhesive layer consisting of a dried coated layer. After that, if necessary, ultraviolet rays or electron beams can be irradiated. There are no particular restrictions, but when using a water-based adhesive, it should be about 30 to 5000 nm. Preferably, the thickness is about 100 to 1000 nm, and more preferably, the thickness is about 100 to 1000 nm. When an electron beam curing adhesive or the like is used, the thickness is preferably about 0.1 to 100 μm. More preferably, it is about 0.5 to 10 μm.

[0089] An embodiment in which the functional layer and the first transparent protective film are bonded together via the adhesive layer. In the present invention, the total thickness of the functional layer and the adhesive layer is set to a value from the viewpoint of suppressing polyenization of the polarizing film. From this viewpoint, the thickness is preferably 0.2 μm or more, and more preferably 0.3 μm or more. It is more preferable that the thickness is 0.6 μm or more, and the durability of the polarizing plate under high temperature and high humidity conditions is high. From this viewpoint, it is preferable that the thickness is 11 μm or less, and more preferably 6 μm or less. , more preferably 4 μm or less, and even more preferably 2 μm or less. .

[0090] The polarizing film, the functional layer, the first and second transparent protective films, and the other layers are The surface may be subjected to a surface modification treatment or an easy-adhesion treatment.

[0091] Examples of the surface modification treatment include corona treatment, plasma treatment, primer treatment, and kettle treatment. Examples include fluorination treatment.

[0092] The easy-adhesion treatment may be carried out, for example, on a polyester skeleton, a polyether skeleton, or a polycarbonate skeleton. skeleton, polyurethane skeleton, silicone-based, polyamide skeleton, polyimide skeleton, polyvinyl Examples of such treatment include treatment with a forming material containing various resins having an alcohol skeleton or the like.

[0093] the functional layer and the first transparent protective film, the second transparent protective film and the polarizing film , the first and second transparent protective films and the other layer, or the polarizing film and the other layer The layers may be stacked via an intervening layer such as a blocking layer or a refractive index adjusting layer.

[0094] The blocking layer is formed to prevent impurities such as oligomers and ions from being eluted from a transparent protective film or the like. This layer has the function of preventing the block from migrating (penetrating) into the polarizing film. The layer is transparent and can prevent impurities from eluting from a transparent protective film, etc. The material for forming the block layer may be, for example, a urethane prepolymer-based forming material, Examples of the material include cyanoacrylate-based forming materials and epoxy-based forming materials.

[0095] The refractive index adjusting layer is used to adjust the reflection between the transparent protective film and layers having different refractive indices such as a polarizing film. The refractive index adjusting layer is a layer provided to suppress the decrease in transmittance that occurs with the refractive index adjusting layer. Examples of refractive index adjusting materials include silica-based, acrylic-based, acrylic-styrene-based, and melamine-based materials. Examples of suitable forming agents include various resins having a resin system and additives.

[0096] <Laminated polarizing film> The laminated polarizing film (optical laminate) of the present invention is a laminate in which the polarizing film is bonded to an optical layer. The optical layer is not particularly limited, but may be, for example, a reflector, a semi-transmitter, a phase retarder, or the like. Forms of LCD displays such as difference plates (including 1 / 2 and 1 / 4 wavelength plates), viewing angle compensation films, etc. The laminated polarization may include one or more optical layers that may be used in the construction of the laminated polarization. As the optical film, in particular, a reflector or a semi-transmitting reflector is laminated on the polarizing film. a reflective polarizing film or a semi-transmissive polarizing film, An elliptically polarizing film or a circularly polarizing film formed by laminating a difference plate, A wide-viewing angle polarizing film formed by laminating a viewing angle compensation film, or a polarizing film Further, a polarizing film having a brightness enhancing film laminated thereon can be mentioned.

[0097] On one or both surfaces of the polarizing film or the laminated polarizing film, Image display cells such as liquid crystal cells and organic EL elements, and front transparent panels and touch panels on the viewing side An adhesive layer may be provided for bonding other members such as a front transparent member. The adhesive layer is preferably a pressure-sensitive adhesive layer. There are no particular restrictions on the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer. Examples of polymers that can be used include acrylic polymers, silicone polymers, polyesters, and polyurethanes. The base polymer is a polymer such as tan, polyamide, polyether, fluorine-based or rubber-based polymer. In particular, adhesives containing acrylic polymers can be used. It has excellent optical transparency, moderate wettability, cohesion and adhesiveness, and is weather-resistant and heat-resistant. The best ones are preferably used.

[0098] The adhesive layer may be attached to one or both surfaces of the polarizing film or the laminated polarizing film as appropriate. The adhesive layer can be applied by any suitable method, for example, by preparing an adhesive solution and pouring it onto the adhesive layer. The polarizing film or the laminated polarizing film is directly applied by a suitable spreading method such as a spreading method or a coating method. Alternatively, an adhesive layer is formed on the separator and then the polarizing film is attached to the separator. The thickness of the pressure-sensitive adhesive layer can be determined by the thickness of the adhesive layer to be used. It can be determined appropriately depending on the purpose, adhesive strength, etc., and is generally 1 to 500 μm, and 5 to 200 It is preferable that the thickness is 1 μm, and more preferable that the thickness is 10 to 100 μm. A pressure-sensitive adhesive layer is provided on at least one surface of the polarizing film or the laminated polarizing film. Such a film is called a polarizing film with an adhesive layer or a laminated polarizing film with an adhesive layer.

[0099] The exposed surface of the adhesive layer is covered with a sealant to prevent contamination until it is put into practical use. It is preferable that the adhesive layer is temporarily attached and covered so that it will not stick under normal handling conditions. The separator can be, for example, a plastic film, Rubber sheets, paper, cloth, nonwoven fabric, net, foam sheet, metal foil, and laminates thereof The appropriate thin sheet may be silicone-based, long-chain alkyl-based, fluorine-based or molybdenum sulfide-based, as required. The film may be coated with an appropriate release agent such as the above.

[0100] <Image display panel and image display device> The image display panel of the present invention comprises an image display cell and the polarizing film or the laminated polarizing film. The image display device of the present invention further comprises the image display panel and a front transparent portion. It has materials.

[0101] Examples of the image display cell include a liquid crystal cell and an organic EL cell. Examples of the liquid crystal cell include a reflective liquid crystal cell that uses external light, and a backlight that uses light from a light source. Transmissive liquid crystal cells that utilize light, semi-transmissive and semi-reflective liquid crystal cells that utilize both external light and light from the light source, The liquid crystal cell may be a liquid crystal cell that utilizes light from a light source. In this case, the image display device (liquid crystal display device) is provided on the side opposite to the visible side of the image display cell (liquid crystal cell). A polarizing film is also arranged on the light source side, and a light source is also arranged on the polarizing film. It is preferable that the liquid crystal cell is bonded to the substrate via an appropriate adhesive layer. The driving method is, for example, VA mode, IPS mode, TN mode, STN mode, etc. Any type of alignment such as bend alignment (π type) can be used.

[0102] The organic EL cell may be, for example, a transparent electrode, an organic light-emitting layer, and a metal electrode on a transparent substrate. and the like are preferably laminated in order to form a light-emitting body (organic electroluminescence light-emitting body). The organic light-emitting layer is a laminate of various organic thin films, for example, triphenyl A hole injection layer made of an amine derivative, etc., and a light emitting layer made of a fluorescent organic solid such as anthracene. a laminate of such a light-emitting layer and an electron injection layer made of a perylene derivative or the like; Alternatively, various layer structures may be employed, such as a stack of a hole injection layer, a light emitting layer, and an electron injection layer.

[0103] The front transparent member disposed on the viewing side of the image display cell may be, for example, a front transparent plate ( The front transparent plate may be a sheet having an appropriate mechanical strength. A transparent plate having a certain degree of hardness and thickness is used. Such a transparent plate can be, for example, an acrylic plate. A transparent resin plate such as a polyethylene terephthalate resin or a polycarbonate resin, or a glass plate is used. The touch panel may be, for example, a resistive type, a capacitive type, an optical type, or an ultrasonic type. Various touch panels, such as glass panels and transparent resin panels with touch sensor functions, are used. When a capacitive touch panel is used as the front transparent member, A front transparent panel made of glass or a transparent resin plate is provided on the viewing side of the panel. It is preferable that: [Example]

[0104] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. However, it is not limited to the above.

[0105] Example 1 <Preparation of polarizing film> Amorphous isophthalic acid copolymer polyethylene terephthalate with a water absorption rate of 0.75% and a Tg of 75°C One side of the base material is a PET (IPA copolymer) film (thickness: 100 μm) that has been corona treated. Then, on this corona treated surface, polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 % by mole and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl-modification degree 4. 6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name "GOSEFIMER A solution containing 100% ethanol (Z200) in a ratio of 9:1 was applied at 25°C and dried to form a film with a thickness of 11 μm. A PVA-based resin layer was formed to prepare a laminate. The obtained laminate was placed in an oven at 120°C. The free end was uniaxially stretched 2.0 times in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds (air supplementation). Next, the laminate was placed in an insolubilizing bath (100 parts by weight of water, 100 parts by weight of water) at a liquid temperature of 30°C. The sample was immersed in an aqueous solution of boric acid obtained by blending 4 parts by weight of boric acid for 30 seconds (insolubilization treatment). Next, the polarizing plate was immersed in a dye bath at a temperature of 30°C, and the iodine concentration and time were adjusted so that the polarizing plate had a predetermined transmittance. The fabric was then immersed in a crosslinking bath (100% by weight of water) at a liquid temperature of 30°C. parts by weight of boric acid, 3 parts by weight of potassium iodide, and 3 parts by weight of boric acid. The laminate was then immersed in a boric acid solution at a liquid temperature of 70°C for 30 seconds (crosslinking treatment). Aqueous solution (100 parts by weight of water, 4 parts by weight of boric acid, 5 parts by weight of potassium iodide) While immersed in the aqueous solution obtained by compounding, the material is rotated longitudinally (longitudinal direction) between rolls with different peripheral speeds. ) was uniaxially stretched to a total stretching ratio of 5.5 times (underwater stretching treatment). The layer was placed in a cleaning bath (100 parts by weight of water containing 4 parts by weight of potassium iodide) at a liquid temperature of 30°C. The resulting solution was then immersed in the solution (cleaning treatment). While drying, the film was brought into contact with a SUS heated roll whose surface temperature was kept at 75°C for about 2 seconds ( Drying shrinkage treatment) As a result of the above, an optical film laminate including a polarizing film with a thickness of 5 μm was obtained.

[0106] <Preparation of Resin Composition for Forming Functional Layer> Polyvinyl alcohol resin (Nippon Vinyl Acetate Polyvinyl Alcohol) with a degree of polymerization of 2500 and a degree of saponification of 99.8 mol% A solution of benzophenone-3 (manufactured by Barr, trade name: JC-25H) in pure water and a compound represented by the following general formula (9) A water solution (solid content 25% by weight) containing a water-soluble radical scavenger in a weight ratio of 3:1 after drying and film formation was ) was prepared. [ka]

[0107] <Preparation of polarizing film> The polyethylene terephthalate of the optical film laminate cut into sheets along the stretching axis After peeling off the adhesive film, the polarizing film on the peeled surface was subjected to corona treatment, and the resin prepared above was applied. The composition was applied with a wire bar so that the thickness after drying was 0.8 μm, and then heated at 60°C. After drying for 5 minutes, a functional layer was formed on the polarizing film. The cross section was cut using a microscope (Leica, "EM UC7") and metal ions were spat onto the cut surface. After applying the coating, the film thickness was measured using an SEM (JEOL Ltd., "JSM-7100F") The results are shown in Table 1. Next, a first transparent protective film was attached to the film via a water-based adhesive. As the film, an acrylic resin film (with a moisture permeability of 100 g / (m 2 24h), Toyo Kohan The adhesive-treated surface of the laminate (manufactured by Epson Corporation, "RZ30") was bonded to the functional layer using a roll laminator. Then, it is heated and dried in an oven (at 60°C for 4 minutes) to remove the polarizing filter. The water-based adhesive was a polyvinyl alcohol containing an acetoacetyl group. Resin (average polymerization degree 1,200, saponification degree 98.5 mol%, acetoacetylation degree 5 mol%) The aqueous solution used contained methylol melamine in a weight ratio of 3:1. After lamination of the agent and the functional layer, the functional layer swells and deforms, causing the interface to mix and making separation difficult. Therefore, the total thickness of the functional layer and the water-based adhesive layer was measured by SEM in the same manner as the functional layer. The film thickness was measured using the following method. The results are shown in Table 1.

[0108] <Fabrication of pseudo image display panel> The polarizing film obtained above is used, and a second transparent protective film is applied to the surface where the polarizing film is exposed. As a film, a 48 μm thick triacetyl cellulose film (moisture permeable) with a hard coat layer was used. The degree is 300g / (m 2 24h), Fujifilm, "TJ40UL") triacetyl After bonding it to the cellulose film surface using the water-based adhesive, it was then placed in an oven. The film was then heated and dried in a room at 60°C for 4 minutes. The surface is attached to a small piece of glass (pseudo image display cell) measuring 45 x 50 mm with adhesive. A pseudo image display panel was fabricated.

[0109] <Evaluation of changes in single-piece transmittance under high temperature conditions (1)> The pseudo image display panel obtained above was placed in a hot air oven at a temperature of 105°C for 500 hours. The single-piece transmittance (ΔTs) was measured before and after heating. Ts 500 When this is the case, the change in single transmittance (ΔTs) was calculated using the following formula. ΔTs(%)=Ts 500 -Ts0 The single transmittance was measured optically using a UV-visible spectrophotometer (Otsuka Electronics, "LPF-200") The characteristics were measured and the initial single unit transmittance Ts0 was obtained. The Y value is corrected for visibility using a 2-degree field of view (C light source) at -1982. The length is 380 to 780 nm (in 5 nm increments). The results for ΔTs are shown in Table 1. .

[0110] <Evaluation of changes in single-piece transmittance under high temperature conditions (2)> The pseudo image display panel obtained above was left standing in a hot air oven at a temperature of 95°C for 500 hours. The results of ΔTs were calculated in the same manner as in the evaluation (1) above. show.

[0111] Based on the heat resistance evaluation results, the evaluation was made according to the following criteria. The evaluation results are shown in Table 1. ◎: 3% ≥ ΔTs ≥ 0 ○: 5% ≥ ΔTs > 3% ×: ΔTs<0

[0112] <Example 2> The same procedure as in Example 1 was carried out except that the thickness of the functional layer single film was set to 0.4 μm. A polarizing film and a pseudo-image panel were prepared and subjected to evaluation. The results are shown in Table 1.

[0113] Example 3 The same procedure as in Example 1 was carried out except that the thickness of the functional layer monolayer was 1.5 μm. A polarizing film and a pseudo-image panel were prepared and subjected to evaluation. The results are shown in Table 1.

[0114] Example 4 The water-soluble radical scavenger contained in the functional layer was adjusted to a solid content of 15% by weight. A polarizing film and a pseudo image panel were prepared in the same manner as in Example 1, except that the polarizing film and the pseudo image panel were evaluated. The results are shown in Table 1.

[0115] <Comparative Example 1> The polarizing film and the pseudo image panel were prepared in the same manner as in Example 1, except that the functional layer was not formed. A panel was prepared and subjected to evaluation. The results are shown in Table 1.

[0116] [Table 1] [Explanation of symbols]

[0117] 10(a): Polarizing film (viewing side polarizing film) 10(b): Polarizing film (rear polarizing film) 11: Polarizing film 12: Functional layer 13: First transparent protective film 14: Second transparent protective film 20: Adhesive layer 40 and 50: adhesive layer or adhesive layer 80: Front transparent component 90: Image display cell 100: Image display device

Claims

1. A polarizing film constituting an image display device having an image display cell, the polarizing film has a polarizing membrane, a functional layer, an adhesive layer, and a first transparent protective film; the functional layer is adjacent to the polarizing film on the image display cell side, and contains a water-soluble radical scavenger; A polarizing film, characterized in that the first transparent protective film is provided on the functional layer via an adhesive layer.

2. 2. The polarizing film according to claim 1, wherein the functional layer contains a polyvinyl alcohol-based resin.

3. 3. The polarizing film according to claim 1, wherein the water-soluble radical scavenger is a compound having a nitroxy radical or a nitroxide group.

4. 4. The polarizing film according to claim 1, wherein the functional layer has a thickness of 10 μm or less.

5. 5. The polarizing film according to claim 1, wherein the polarizing film has a thickness of 15 μm or less.

6. 6. The polarizing film according to claim 1, wherein the adhesive forming the adhesive layer is a water-based adhesive.

7. 7. The polarizing film according to claim 1, wherein the total thickness of the functional layer and the adhesive layer is 0.2 μm or more and 11 μm or less.

8. 8. The polarizing film according to claim 1, further comprising a second transparent protective film provided on the surface of the polarizing film opposite to the image display cell side.

9. A laminated polarizing film, comprising the polarizing film according to any one of claims 1 to 8 laminated to an optical layer.

10. 10. An image display panel comprising an image display cell and the polarizing film according to claim 1 or the laminated polarizing film according to claim 9.

11. An image display device comprising the image display panel according to claim 10 and a front transparent member.

Images