WO2023276936A1

WO2023276936A1 - Polarizing film and image display device

Info

Publication number: WO2023276936A1
Application number: PCT/JP2022/025540
Authority: WO
Inventors: 優人座間; 達也山崎; 裕宗春田
Original assignee: 日東電工株式会社
Priority date: 2021-06-30
Filing date: 2022-06-27
Publication date: 2023-01-05
Also published as: KR20240025500A; JPWO2023276936A1; CN117321461A; TW202309564A

Abstract

Provided is a polarizing film in which a transparent protective film is stacked on at least one surface of a polarizer with an adhesive layer therebetween, the polarizing film being characterized in that in at least part of the polarizer, a non-polarizing portion is formed, and a dimensional shrinkage rate X1 of the polarizing film including the non-polarizing portion after the polarizing film is left for 72 hours at 85°C in a humidity environment of 85% is 1.0% or less. H1×d1 ≥ 0.8 is preferable where H1 (GPa) is the hardness of the non-polarizing portion, and d1 is the thickness of the non-polarizing portion. H3×T3 < 50 is preferable where H3 (GPa) is the hardness of the transparent protective film, and T3 (g/m2) is the moisture permeability of the transparent protective film. H2×d2 ≥ 0.20 is preferable where H2 (GPa) is the hardness of a portion abutting on the non-polarizing portion of the adhesive layer, and d2 (μm) is the thickness thereof.

Description

Polarizing film and image display device

The present invention relates to a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizer via an adhesive layer. The polarizing film can form an image display device such as a mobile phone, a car navigation device, a monitor for a personal computer, or a television as an optical film laminated with the polarizing film alone.

Some image display devices such as mobile phones and notebook personal computers (PCs) are equipped with internal electronic parts such as sensors. In recent years, due to the rapid spread of smart phones and touch panel type information processing devices, there is a demand for further improvements in sensor performance and the like. In addition, in order to cope with the diversification of the shape and the sophistication of image display devices, there is a demand for a polarizing film having partial polarizing performance. In order to meet these demands, a polarizer has been proposed in which a non-polarizing portion formed by chemical treatment is formed at a predetermined portion (for example, Patent Documents 1 and 2).

Korean Patent Publication No. 10-2015-0086159 JP 2015-215609 A

In recent years, image display devices such as mobile phones and PCs, especially mobile phones with flexible displays, image display devices such as PCs, and polarizing films used for in-vehicle applications have been tested for durability under high temperature and high humidity conditions. For example, there is a humidification durability test in which the film is exposed to an environment of 85° C.-85% humidity for a predetermined period of time. When the non-polarizing portion of the polarizer and the transparent protective film laminated on the polarizer swell due to such a humidification durability test, the optical functions of the polarizing film may be impaired.

The present invention was developed in view of the above circumstances, and aims to provide a polarizing film and an image display device which are equipped with a polarizer having a non-polarizing portion and which have excellent optical functions even under high temperature and high humidity conditions.

The above issues can be resolved by the following configuration. That is, the present invention provides a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizer via an adhesive layer, wherein the polarizer has a non-polarizing portion formed at least in part. A polarizing film (1) characterized in that the dimensional shrinkage rate X1 of the polarizing film containing the non-polarizing portion after being left in an environment of 85° C.-85% humidity for 72 hours is 1.0% or less. Regarding. In the present invention, the "dimensional shrinkage rate of the polarizing film" is obtained by preparing a polarizing film sample having a sample size of 10 cm x 10 cm, and measuring the dimensional shrinkage rate in the MD direction or the TD direction, more preferably the dimensional shrinkage rate in the MD direction where the dimensional change rate is large. shall mean In general, the "MD direction" corresponds to the "absorption axis direction of the polarizer".

In the polarizing film (1), when the hardness of the non-polarizing portion is H1 (GPa) and the thickness of the non-polarizing portion is d1,
H1×d1≧0.8
A polarizing film (2) is preferred.

In the polarizing film (1) or (2), when the hardness of the transparent protective film is H3 (GPa) and the moisture permeability of the transparent protective film is T3 (g/m ² ),
H3×T3<50
A polarizing film (3) is preferred.

In any one of the polarizing films (1) to (3), when the hardness of the portion of the adhesive layer in contact with the non-polarizing portion is H2 (GPa) and the thickness is d2 (μm),
H2×d2≧0.20
A polarizing film (4) is preferred.

In any one of the polarizing films (1) to (4), the polarizing film (5) has an adhesive layer thickness of 2 μm or less between a portion of the polarizer other than the non-polarizing portion and the transparent protective film. preferable.

Further, the present invention includes the polarizing film according to any one of the above (1) to (5), wherein the non-polarizing portion of the polarizing film is arranged at a position corresponding to the sensor portion. It relates to a display device.

In recent years, there are many polarizing film applications that are used under high temperature and high humidity, and as mentioned above, it is important to ensure optical functions even under high temperature and high humidity. When the polarizing film is placed in a high-temperature and high-humidity environment, for example, in an environment of 85° C. to 85% humidity, other parts of the polarizer than the non-polarizing part tend to shrink, and as a result, a force is exerted in the direction of stretching the non-polarizing part. The non-polarizing portion is likely to be deformed because the non-polarizing portion is likely to be affected. In addition, since the non-polarized portion tends to swell under the influence of moisture under high temperature and high humidity conditions, the shape of the non-polarized portion also tends to change. The polarizing film according to the present invention is designed so that the dimensional shrinkage X1 of the polarizing film containing the non-polarizing portion after being left in an environment of 85° C.-85% humidity for 72 hours is 1.0% or less. . As a result, since the shape change of the non-polarizing portion can be suppressed, as a result, it is possible to make the optical function of the polarizing film excellent even under high temperature and high humidity, and an image display comprising such a polarizing film The device can be used for a long time.

In particular, in the present invention, (1) when H1 (GPa) is the hardness of the non-polarizing portion and d1 is the thickness of the non-polarizing portion, (2) the hardness of the transparent protective film is is H3 (GPa), and the moisture permeability of the transparent protective film is T3 (g/m ² ). If H2×d2≧0.20, where H2 (GPa) is the hardness and d2 (μm) is the thickness, the shape change of the non-polarizing portion can be further suppressed. As a result, the optical function of the polarizing film can be improved even under high temperature and high humidity, and the image display device provided with such a polarizing film can be used for a longer period of time.

BRIEF DESCRIPTION OF THE DRAWINGS It is an example of the cross-sectional schematic diagram of the polarizing film which concerns on one Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the thickness ratios in the drawings are merely examples, and the present invention is not limited to these.

FIG. 1 shows an example of a cross-sectional schematic diagram of a polarizing film according to one embodiment of the present invention. A polarizing film 10 of this embodiment is obtained by laminating a transparent protective film 3 on one side of a polarizer 1 with an adhesive layer 2 interposed therebetween. In the present invention, a transparent protective film may be laminated on both sides of the polarizer via an adhesive layer.

A non-polarizing portion 1A is formed in at least a portion of the polarizer 1. A method for forming the non-polarizing portion of the polarizer will be described later. When the non-polarizing portion is formed in the polarizer, depending on the processing method, the processed surface of the non-polarizing portion is structurally more likely to be recessed than the other portion (polarizing portion) of the polarizer. The embodiment shown in FIG. 1 shows an example in which recesses 1h are formed on the processed surface of the polarizer 1. FIG. In the embodiment shown in FIG. 1, only the treated surface (the upper side of the drawing) has the concave portion 1h, and the lower side of the drawing has no concave portion. The polarizer face opposite 1h may be somewhat concave. In such a case, according to the present invention, the side with the larger depth of the recess (usually, the recess on the side of the surface processed to form the non-polarizing portion in the polarizer) is defined as the recess 1h.

The polarizing film 10 shown in FIG. 1 is designed so that the dimensional shrinkage rate X1 of the polarizing film containing the non-polarizing portion 1A after being left in an environment of 85° C. and 85% humidity for 72 hours is 1.0% or less. ing. As a result, the optical function of the polarizing film 10 can be made excellent even under high temperature and high humidity, and the image display device provided with such a polarizing film 10 can be used for a long period of time. A method for measuring the dimensional shrinkage rate X1 of the polarizing film including the non-polarizing portion 1A will be described later.

In order to improve the optical functions of the polarizing film 10 under high temperature and high humidity conditions, the dimensional shrinkage ratio X1 of the polarizing film containing the non-polarizing portion 1A is preferably 0.8% or less, and 0.8% or less. It is more preferably 5% or less, and particularly preferably 0.3% or less.

In the polarizing film 10 shown in FIG. 1, when H1 (GPa) is the hardness of the non-polarizing portion 1A and d1 is the thickness of the non-polarizing portion 1A, when H1×d1≧0.8, under high temperature and high humidity, Even if the non-polarizing portion 1A swells due to moisture entering the non-polarizing portion 1A and the non-polarizing portion 1A expands (changes in shape) due to the contraction of the polarizing portion under high temperature and high humidity conditions, the non-polarizing portion 1A Since the hardness and/or thickness of the non-polarizing portion 1A are sufficiently secured, it is possible to further suppress the shape change of the non-polarizing portion 1A. As a result, it is possible to improve the optical functions of the polarizing film even under high temperature and high humidity conditions. A method for measuring the hardness H1 of the non-polarizing portion 1A and the thickness d1 of the non-polarizing portion 1A will be described later.

In order to improve the optical function of the polarizing film 10 under high temperature and high humidity, H1×d1≧1.0 is preferable, and H1×d1≧1.2 is more preferable.

In the polarizing film 10 shown in FIG. 1, when the hardness of the transparent protective film 3 is H3 (GPa) and the moisture permeability of the transparent protective film 3 is T3 (g/m ² ), H3×T3<50. It is preferable because the optical function of the polarizing film 10 can be improved even under high temperature and high humidity. For example, when the hardness H3 of the transparent protective film 3 is low, the amount of moisture (moisture permeability) from the outside is suppressed, that is, by designing the moisture permeability T3 of the transparent protective film 3 to be low, the non-polarizing portion 1A swelling of the non-polarizing portion 1A can be further suppressed. In addition, when the moisture permeability T3 of the transparent protective film 3 is high, the moisture content (moisture permeability) from the outside increases. Shape change can be suppressed more.

In order to improve the optical function of the polarizing film 10 under high temperature and high humidity conditions, H3×T3<40 is more preferable, and H3×T3<30 is particularly preferable.

In the polarizing film 10 shown in FIG. 1, when H2 (GPa) is the hardness of the portion of the adhesive layer 2 in contact with the non-polarizing portion 1A and d2 (μm) is the thickness, H2×d2≧0.20. , the thickness d2 and hardness H2 of the adhesive layer 2 in contact with the non-polarizing portion 1A are above a certain level. Shape change can be suppressed more. As a result, it is possible to improve the optical functions of the polarizing film even under high temperature and high humidity conditions. “A portion of the adhesive layer 2 that adheres the polarizer 1 and the transparent protective film 3 and that is in contact with the non-polarized portion 1A of the polarizer 1” means the non-polarized portion of the adhesive layer 2 in plan view. It means the whole part overlapping with 1A.

In order to improve the optical function of the polarizing film 10 under high temperature and high humidity conditions, H2×d2≧0.30 is more preferable, and H2×d2≧0.35 is particularly preferable. .

The thicker the adhesive layer that bonds the polarizer and the transparent protective film, the more preferable it is because it can suppress the expansion of air bubbles under high temperature and high humidity. Durability tends to deteriorate. In the polarizing film 10 shown in FIG. 1, when the thickness of the adhesive layer between the portion other than the non-polarizing portion 1A of the polarizer 1 (hereinafter also referred to as "polarizing portion") and the transparent protective film 3 is 2 μm or less, It is preferable because expansion of air bubbles under high temperature and high humidity can be suppressed while maintaining the wet heat durability of the polarizing film.

Each member constituting the polarizing film of the present invention will be described below.

[Polarizer]
A polarizer included in the polarizing film is composed of a resin film containing a dichroic substance. A non-polarizing portion is formed in the polarizer. The non-polarizing portion is typically a portion (low-concentration portion) in which the content of the dichroic substance is lower than that of the portion other than the non-polarizing portion of the polarizer. However, the non-polarizing portion in the present invention may be a layer from which the dichroic material is removed from the polarizer, or may be another layer containing no dichroic material, and is not limited to these. According to such a structure, cracks and delamination can be reduced mechanically (for example, by a method of mechanically removing using an engraving blade punch, plotter, water jet, etc.) compared to the case where through holes are formed. Quality problems such as delamination (delamination) and glue extrusion are avoided.

As a method of introducing a non-polarizing portion into a polarizer, a method of extracting a dichroic substance from the polarizer by chemical treatment and decolorizing it to form a non-polarizing portion in the polarizer (hereinafter referred to as "chemical treatment method" Alternatively, a method of forming a non-polarized portion by decomposing a dichroic substance with laser light or the like (hereinafter also referred to as a “laser method”). Among these methods, the chemical treatment method can adjust the content of the dichroic substance itself in the non-polarized portion to be low, and maintains the transparency of the non-polarized portion better than the laser method. preferable.

In the polarizing film, the number, arrangement, shape, size, etc. of the non-polarizing portions can be appropriately designed. For example, it is designed according to the position, shape, size, etc. of the sensor section of the image display device to be mounted. Specifically, it is designed so that the non-polarizing portion does not correspond to the portion other than the sensor of the image display device (for example, the image display portion).

The transmittance of the non-polarized portion (for example, transmittance measured with light having a wavelength of 550 nm at 23° C.) is preferably 50% or more, more preferably 60% or more, still more preferably 75% or more, and particularly preferably 90% or more. is. With such a transmittance, desired transparency can be ensured. For example, when the non-polarizing portion corresponds to the sensor portion of the image display device, it is possible to prevent adverse effects on the imaging performance of the sensor.

The polarizer preferably exhibits absorption dichroism in the wavelength range of 380 nm to 780 nm. Single transmittance (Ts) of the polarizing portion of the polarizer (part other than the non-polarizing portion of the polarizer) is preferably 39% or more, more preferably 39.5% or more, still more preferably 40% or more, and particularly preferably 40.5% or more. The theoretical upper limit of single transmittance is 50%, and the practical upper limit is 46%. In addition, the single transmittance (Ts) is the Y value measured with a JIS Z8701 2-degree field of view (C light source) and corrected for visibility. name: V7100). The degree of polarization of the polarizing portion of the polarizer is preferably 99.8% or higher, more preferably 99.9% or higher, and even more preferably 99.95% or higher.

The thickness of the polarizer (resin film) can be set to any appropriate value. The thickness of the polarizer is typically 0.5 μm to 80 μm. The thickness is preferably 30 μm or less, more preferably 25 μm or less, even more preferably 18 μm or less, particularly preferably 12 μm or less, and even more preferably less than 8 μm. The thickness is preferably 1 μm or more. As the thickness of the resin film to be the polarizer is thinner, the content of the dichroic substance can be reduced in a shorter period of time in the step of contacting with the basic solution, which will be described later.

Examples of the dichroic substance include iodine and organic dyes. These may be used alone or in combination of two or more. Iodine is preferably used. This is because a non-polarized portion can be favorably formed by contact with a basic solution, which will be described later.

The content of the dichroic substance in the non-polarizing portion is preferably 1.0% by weight or less, more preferably 0.5% by weight or less, and even more preferably 0.2% by weight or less. If the content of the dichroic substance in the non-polarizing portion is within this range, the desired transparency can be sufficiently imparted to the non-polarizing portion. Therefore, for example, when the non-polarizing portion is made to correspond to the sensor portion of the image display device, extremely excellent shooting performance can be achieved in terms of both brightness and color. On the other hand, the lower limit of the content of the dichroic substance in the non-polarized portion is usually below the detection limit. When iodine is used as the dichroic substance, the iodine content can be obtained from, for example, a calibration curve prepared in advance using standard samples from X-ray intensities measured by fluorescent X-ray analysis.

The difference between the content of the dichroic substance in other parts and the content of the dichroic substance in the non-polarized part is preferably 0.5% by weight or more, more preferably 1% by weight or more.

Any appropriate resin can be used as the resin forming the resin film. Preferably, a polyvinyl alcohol-based resin (hereinafter referred to as "PVA-based resin") is used. Examples of PVA-based resins include polyvinyl alcohol and ethylene-vinyl alcohol copolymers. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. An ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of the PVA-based resin is usually 85 mol% or more and less than 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. be. The degree of saponification can be determined according to JIS K 6726-1994. By using a PVA-based resin having such a degree of saponification, a polarizer with excellent durability can be obtained. If the degree of saponification is too high, gelation may occur.

The average degree of polymerization of the PVA-based resin can be appropriately selected depending on the purpose. The average degree of polymerization is usually 1,000 to 10,000, preferably 1,200 to 4,500, more preferably 1,500 to 4,300. The average degree of polymerization can be determined according to JIS K 6726-1994.

A polarizer having a non-polarizing portion can be produced by a chemical treatment method in which a resin film containing a dichroic substance is brought into contact with a treatment liquid, such as a basic solution. When iodine is used as the dichroic substance, the iodine content of the contact portion can be easily reduced (decolorized) by contacting the desired portion of the resin film with a basic solution. Specifically, the contact may allow the basic solution to penetrate into the interior of the resin film. The iodine complex contained in the resin film is reduced by the base contained in the basic solution to become iodine ions. By reducing the iodine complex to iodine ions, the transmittance of the contact portion can be improved. Then, the iodine converted into iodine ions moves from the resin film into the solvent of the basic solution. The non-polarized portion thus obtained can maintain its transparency satisfactorily. Specifically, when the iodine complex is destroyed to improve the transmittance, the iodine remaining in the resin film forms an iodine complex again with the use of the polarizer, which may reduce the transmittance. Such problems are prevented when the content is reduced.

Any appropriate method can be adopted as a method for contacting the basic solution. Examples thereof include a method of dropping, coating, or spraying a basic solution onto a resin film, and a method of immersing a resin film in a basic solution.

The resin film may be protected with any suitable protective material so that the basic solution does not come into contact with any part other than the desired part (so that the content of the dichroic substance does not decrease) when the basic solution comes into contact. . Specifically, examples of protective materials for resin films include protective films and surface protective films. The protective film can be used as it is as a protective film for the polarizer. A surface protective film is used temporarily during the production of a polarizer. Since the surface protection film is removed from the resin film at any appropriate timing, it is typically attached to the resin film via an adhesive layer. Another specific example of the protective material is photoresist.

Any appropriate basic compound can be used as the basic compound. Examples of basic compounds include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide, and inorganic alkali metal salts such as sodium carbonate. , organic alkali metal salts such as sodium acetate, aqueous ammonia, and the like. Among these, alkali metal and/or alkaline earth metal hydroxides are preferably used, and sodium hydroxide, potassium hydroxide and lithium hydroxide are more preferably used. This is because the dichroic substance can be efficiently ionized, and the non-polarization portion can be formed more easily. These basic compounds may be used alone or in combination of two or more.

Any appropriate solvent can be used as the solvent for the basic solution. Specific examples include water, alcohols such as ethanol and methanol, ethers, benzene, chloroform, and mixed solvents thereof. Among these, water and alcohol are preferably used because the ionized dichroic substance can be transferred well to the solvent.

The concentration of the basic solution is, for example, 0.01N to 5N, preferably 0.05N to 3N, more preferably 0.1N to 2.5N. If the concentration is within such a range, the desired non-polarized portion can be formed satisfactorily.

The liquid temperature of the basic solution is, for example, 20°C to 50°C. The contact time of the basic solution is set according to, for example, the thickness of the resin film and the type and concentration of the basic compound contained in the basic solution. The contact time is, for example, 5 seconds to 30 minutes, preferably 5 seconds to 5 minutes.

In one embodiment, the surface of the resin film is covered with a surface protective film so that at least a portion thereof is exposed when it comes into contact with a basic solution. For example, it is produced by bonding a polarizer (resin film) with a surface protective film having small circular through holes, and contacting this with a basic solution. At that time, it is preferable that the other side of the resin film (the side on which the surface protective film is not arranged) is also protected.

Note that the resin film may be elongated. When the resin film is elongated, it is preferable to laminate the resin film and the protective material by roll-to-roll. Here, "roll-to-roll" refers to stacking while aligning the longitudinal directions of roll-shaped films while conveying them. Through-holes are formed in the elongated surface protective film at predetermined intervals in the longitudinal direction and/or the width direction thereof, for example. The method for producing a polarizer using the long resin film and the surface protective film used for producing the long resin film are disclosed in JP-A-2016-027135 and JP-A-2016-027136. , JP-A-2016-027137, JP-A-2016-027138, and JP-A-2016-027139, which are incorporated herein by reference.

It is preferable that the resin film be in a state where it can be used as a polarizer when it is brought into contact with the basic solution. Specifically, various treatments such as swelling treatment, stretching treatment, dyeing treatment with the dichroic substance, cross-linking treatment, washing treatment, and drying treatment are preferably performed. In addition, when performing various treatments, the resin film may be a resin layer formed on a substrate. A laminate of a base material and a resin layer can be obtained, for example, by a method of applying a coating liquid containing the resin film-forming material to the base material, a method of laminating a resin film on the base material, or the like.

The above dyeing treatment is typically performed by adsorbing a dichroic substance. Examples of the adsorption method include a method of immersing the resin film in a dyeing solution containing a dichroic substance, a method of coating the resin film with the dyeing solution, and a method of spraying the resin film with the dyeing solution. . A preferred method is to immerse the resin film in a dyeing solution. This is because the dichroic substance can be well adsorbed.

When iodine is used as the dichroic substance, an iodine aqueous solution is preferably used as the staining solution. The amount of iodine compounded is preferably 0.04 to 5.0 parts by weight per 100 parts by weight of water. In order to increase the solubility of iodine in water, it is preferable to add an iodide to the iodine aqueous solution. Potassium iodide is preferably used as the iodide. The amount of iodide compounded is preferably 0.3 to 15 parts by weight per 100 parts by weight of water.

In the above stretching process, the resin film is typically uniaxially stretched 3 to 7 times. The stretching direction can correspond to the absorption axis direction of the resulting polarizer.

When the non-polarized portion of the polarizer is formed by decolorization by chemical treatment, the contact surface (non-polarized portion) of the basic solution is recessed compared to the other polarized portion, thereby forming a recess in the non-polarized portion. be done. The maximum depth of the concave portion varies depending on the thickness of the polarizer and the contact conditions (temperature, time, etc.) with the basic solution, but is 0.1 to 2.0 (μm), particularly 0.1 to 1.0 μm. When it is 0 (μm), visibility of the polarizing film can be easily improved under high temperature and high humidity, which is preferable.

When the non-polarizing portion of the polarizer is formed by decolorization by chemical treatment, the thickness and hardness of the non-polarizing portion depend on the manufacturing conditions of the non-polarizing portion (e.g., polarizing in a 1 mol/L (1N) sodium hydroxide aqueous solution). film immersion time (seconds)", "polarizing film immersion time in 1 mol/L (1N) hydrochloric acid (seconds)", "drying temperature after NaOH treatment and HCl treatment (°C)", etc. It can be changed by making appropriate adjustments.

Any appropriate step may be further included as necessary when manufacturing the polarizer used in the present invention. Examples include a step of reducing alkali metals and/or alkaline earth metals, and removing the basic solution. These steps are performed at any appropriate stage of the manufacturing method described above.

By bringing the basic solution into contact with the resin film, hydroxides of alkali metals and/or alkaline earth metals can remain in the contact area. Also, by bringing a basic solution into contact with the resin film, metal salts of alkali metals and/or alkaline earth metals can be generated at the contact portion. These can generate hydroxide ions, and the generated hydroxide ions act (decompose/reduce) dichroic substances (e.g., iodine complexes) present around the contact area, resulting in non-polarized regions (low concentration range) can be widened. Therefore, by reducing the amount of alkali metal and/or alkaline earth metal, it is possible to suppress the expansion of the non-polarization region over time and maintain the desired shape of the non-polarization portion. Details of the step of reducing alkali metals and/or alkaline earth metals are described in, for example, JP-A-2015-215609, JP-A-2015-215610, and JP-A-2015-215611. This description is incorporated herein by reference.

Specific examples of the method for removing the basic solution and/or the post-crosslinking solution include washing, wiping removal with a waste cloth, suction removal, natural drying, heat drying, air drying, and reduced pressure drying. Cleaning liquids used for cleaning include, for example, water (pure water), alcohols such as methanol and ethanol, and mixtures thereof. Water is preferably used. The number of washings is not particularly limited, and washing may be performed multiple times. When removing by drying, the drying temperature is, for example, 20°C to 100°C.

[Transparent protective film]
In the polarizing film of the present invention, a transparent protective film is laminated on at least one surface of a polarizer via an adhesive layer. In addition, in the polarizing film of the present invention, for example, the same or different transparent protective film may be further provided via an adhesive layer on the surface of the polarizer opposite to the surface on which the transparent protective film is laminated. .

Thermoplastic resins, which are excellent in transparency, mechanical strength, thermal stability, water barrier properties, isotropy, etc., are used as materials for the transparent protective film. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic Polyolefin resins (norbornene-based resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. One or more of any suitable additives may be contained in the transparent protective film. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . If the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

As the material for forming the transparent protective film, a material having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc. is preferable, and in particular, a material having a moisture permeability of 150 g/m ² /24h or less. is more preferred, 140 g/m ² /24h or less is particularly preferred, and 120 g/m ² /24h or less is even more preferred.

A functional layer such as a hard coat layer, an antireflection layer, an antisticking layer, a diffusion layer or an antiglare layer can be provided on the surface of the transparent protective film to which the polarizer is not adhered. Functional layers such as the hard coat layer, antireflection layer, anti-sticking layer, diffusion layer, and antiglare layer can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film. can also

The thickness of the transparent protective film can be determined as appropriate, but is generally about 1 to 500 μm, preferably 1 to 300 μm, more preferably 5 to 200 μm, from the viewpoint of strength, workability such as handleability, and thinness. preferable. Further, it is preferably 10 to 200 μm, more preferably 20 to 80 μm.

A retardation film having a front retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more can be used as the transparent protective film. The front retardation is usually controlled in the range of 40-200 nm, and the thickness direction retardation is usually controlled in the range of 80-300 nm. When a retardation film is used as the transparent protective film, the thickness can be reduced because the retardation film also functions as a transparent protective film. In the polarizing film of the present invention, for example, a retardation film may be further provided via an adhesive layer on the surface of the polarizer opposite to the surface on which the transparent protective film is laminated.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an oriented film of a liquid crystal polymer, and a film in which an oriented layer of a liquid crystal polymer is supported. Although the thickness of the retardation film is not particularly limited, it is generally about 20 to 150 μm.

As the retardation film, the following formulas (1) to (3):
0.70<Re[450]/Re[550]<0.97 (1)
1.5×10 ⁻³ <Δn<6×10 ⁻³ (2)
1.13<NZ<1.50 (3)
(Wherein, Re [450] and Re [550] are the in-plane retardation values of the retardation film measured with light having wavelengths of 450 nm and 550 nm, respectively, at 23 ° C., and Δn is the slow phase of the retardation film In-plane birefringence that is nx-ny when the refractive indices in the axial direction and the fast axis direction are nx and ny, respectively, and NZ is the refractive index in the thickness direction of the retardation film, (ratio of nx-nz, which is birefringence in the thickness direction, to nx-ny, which is in-plane birefringence) may be used.

A retardation layer may be provided in the polarizing film according to the present invention. The retardation layer may be a single layer or multiple layers, and the retardation layer may also serve as a protective layer for the polarizer. In the polarizing film of the present invention, for example, a retardation layer may be provided via an adhesive layer on the surface of the polarizer opposite to the surface on which the transparent protective film is laminated. The type, number, combination, arrangement position, and characteristics of the retardation layer can be appropriately set according to the purpose.

A liquid crystalline compound is preferably used for forming the retardation layer. A solvent containing the liquid crystalline compound can be applied using, for example, a wire bar, gap coater, comma coater, gravure coater, slot die, or the like. At this time, the applied liquid crystalline solution may be dried naturally or dried by heating. The liquid crystalline solution is preferably applied at a concentration lower than the isotropic phase-liquid crystal phase transition concentration, that is, in an isotropic phase state. In this case, the orientation can be stably achieved by a method such as rubbing treatment or photo-orientation.

[Adhesive layer]
In the polarizing film of the present invention, a transparent protective film is laminated on at least one surface of a polarizer via an adhesive layer. Such an adhesive layer can be formed of, for example, a cured product layer of a curable resin composition.

The present invention is characterized in that the dimensional shrinkage rate X1 of the non-polarizing portion formed in the polarizer is designed to be 1.0% or less after being left in an environment of 85° C. and 85% humidity for 72 hours. There is The material constituting the adhesive layer so as to satisfy the dimensional shrinkage ratio X1 may be only the curable resin composition described later, or the curable resin composition may be used in combination with an easily bonding composition.

In the polarizing film 10 of the present invention, the thickness of the adhesive layer between the polarizing portion of the polarizer 1 and the transparent protective film 3 is preferably 2 µm or less, more preferably 1.8 µm or less. The lower limit of the thickness of the adhesive layer is preferably 0.5 μm in order to ensure adhesiveness.

The curable resin composition can be classified into a radically polymerizable curable resin composition and a cationically polymerizable curable resin composition. In the present invention, active energy rays with a wavelength range of 10 nm to less than 380 nm are expressed as ultraviolet rays, and active energy rays with a wavelength range of 380 nm to 800 nm are expressed as visible rays.

Examples of monomer components constituting the radically polymerizable curable resin composition include compounds having radically polymerizable functional groups of carbon-carbon double bonds such as (meth)acryloyl groups and vinyl groups. These monomer components can be either monofunctional radically polymerizable compounds or multifunctional radically polymerizable compounds having two or more polymerizable functional groups. Moreover, these radical polymerizable compounds can be used individually by 1 type or in combination of 2 or more types. As these radically polymerizable compounds, for example, compounds having a (meth)acryloyl group are suitable. In the present invention, (meth)acryloyl means an acryloyl group and/or a methacryloyl group, and "(meth)" has the same meaning below.

Examples of monofunctional radically polymerizable compounds include (meth)acrylamide derivatives having a (meth)acrylamide group. A (meth)acrylamide derivative is preferable in terms of ensuring adhesiveness to a polarizer and various transparent protective films, and in terms of high polymerization rate and excellent productivity. Specific examples of (meth)acrylamide derivatives include N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N - N-alkyl group-containing (meth)acrylamide derivatives such as butyl (meth)acrylamide and N-hexyl (meth)acrylamide; N-methylol (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, N-methylol-N- N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as propane (meth)acrylamide; N-aminoalkyl group-containing (meth)acrylamide derivatives such as aminomethyl (meth)acrylamide and aminoethyl (meth)acrylamide; N-methoxymethyl N-alkoxy group-containing (meth)acrylamide derivatives such as acrylamide and N-ethoxymethylacrylamide; N-mercaptoalkyl group-containing (meth)acrylamide derivatives such as mercaptomethyl (meth)acrylamide and mercaptoethyl (meth)acrylamide; be done. Further, the heterocycle-containing (meth)acrylamide derivative in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle includes, for example, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine etc.

Among the (meth)acrylamide derivatives, N-hydroxyalkyl group-containing (meth)acrylamide derivatives are preferred from the viewpoint of adhesion to polarizers and various transparent protective films. , for example, various (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl ( meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl ( Examples include (meth)acrylic acid (C1-20) alkyl esters such as meth)acrylate and n-octadecyl (meth)acrylate.

Examples of the (meth)acrylic acid derivative include cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; 2-isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, dicyclopentenyl (meth) ) Polycyclic (meth)acrylates such as acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, 2-ethoxy Ethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, alkylphenoxy polyethylene glycol (meth) acrylate, etc. Alkoxy group- or phenoxy group-containing (meth)acrylates and the like are included.

Further, the (meth)acrylic acid derivatives include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4- Hydroxyalkyl (meth)acrylates such as hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate and 12-hydroxylauryl (meth)acrylate and hydroxyl group-containing (meth)acrylates such as [4-(hydroxymethyl)cyclohexyl]methylacrylate, cyclohexanedimethanol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate; glycidyl (meth)acrylate, Epoxy group-containing (meth)acrylates such as 4-hydroxybutyl (meth)acrylate glycidyl ether; 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate, tetra Halogen-containing (meth)acrylates such as fluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, etc. ) acrylates; alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate; 3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth)acrylate, 3-ethyl-oxetanylmethyl (meth)acrylate , 3-Butyl-oxetanylmethyl (meth)acrylate, 3-hexyloxetanylmethyl (meth)acrylate, and other oxetane group-containing (meth)acrylates; Tetrahydrofurfuryl (meth)acrylate, butyrolactone (meth)acrylate, and other heterocycles and (meth) acrylates, hydroxypivalic acid neopentyl glycol (meth) acrylic acid adducts, p-phenylphenol (meth) acrylate and the like.

Also, examples of monofunctional radically polymerizable compounds include carboxyl group-containing monomers such as (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

Examples of monofunctional radically polymerizable compounds include lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, Vinyl-based monomers having a nitrogen-containing heterocyclic ring such as vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine are included.

Also, as the monofunctional radically polymerizable compound, a radically polymerizable compound having an active methylene group can be used. A radically polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acrylic group at the end or in the molecule and an active methylene group. Active methylene groups include, for example, an acetoacetyl group, an alkoxymalonyl group, a cyanoacetyl group, and the like. Preferably, the active methylene group is an acetoacetyl group. Specific examples of radically polymerizable compounds having an active methylene group include 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, 2-acetoacetoxy-1-methylethyl (meth)acrylate, and the like. 2-ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl) acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, N-(2-acetoacetylaminoethyl)acrylamide and the like. The radically polymerizable compound having an active methylene group is preferably acetoacetoxyalkyl (meth)acrylate.

Examples of polyfunctional radically polymerizable compounds having two or more polymerizable functional groups include tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. , 1,9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide addition di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecanedimethanol di(meth) Acrylates, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta (Meth)acrylates, dipentaerythritol hexa(meth)acrylate, esters of (meth)acrylic acid and polyhydric alcohols such as EO-modified diglycerol tetra(meth)acrylate, 9,9-bis[4-(2-) (Meth)acryloyloxyethoxy)phenyl]fluorene. Specific examples include Aronix M-220 (manufactured by Toagosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DCP-A (Kyoeisha Chemical Co., Ltd.) (manufactured by Sartomer), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer), and the like. Various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, various (meth)acrylate monomers, and the like can also be used as necessary.

In the present invention, the curable resin composition may contain an acrylic oligomer obtained by polymerizing a (meth)acrylic monomer in addition to the radically polymerizable compound. By containing an acrylic oligomer in the adhesive composition, curing shrinkage when the composition is irradiated with an active energy ray and cured is reduced, and the adhesive layer and the adherend such as a polarizer and an optical film It is possible to reduce the interfacial stress with As a result, deterioration in adhesion between the adhesive layer and the adherend can be suppressed.

Since the curable resin composition preferably has a low viscosity in consideration of workability and uniformity during coating, an acrylic oligomer obtained by polymerizing a (meth)acrylic monomer should also have a low viscosity. preferable. The acrylic oligomer which has a low viscosity and can prevent curing shrinkage of the adhesive layer preferably has a weight-average molecular weight (Mw) of 15,000 or less, more preferably 10,000 or less, and particularly 5,000 or less. preferable. On the other hand, in order to sufficiently suppress curing shrinkage of the cured product layer (adhesive layer), the weight average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1000 or more. 1500 or more is particularly preferable. Specific examples of the (meth)acrylic monomer constituting the acrylic oligomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, 2-methyl- 2-nitropropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, S-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl ( (Meth)acrylic acid (C1-20) alkyl esters such as meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, N-octadecyl (meth)acrylate, and further, for example, cycloalkyl (meth) ) acrylates (e.g., cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), aralkyl (meth) acrylates (e.g., benzyl (meth) acrylate, etc.), polycyclic (meth) acrylates (e.g., 2-isobornyl (meth) ) acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, etc.), hydroxyl group-containing (meth) ) Acrylic esters (e.g., hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate, etc.), alkoxy group- or phenoxy group-containing (meth)acryl Acid esters (2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxy ethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic acid esters (e.g., glycidyl (meth)acrylate, etc.), halogen-containing (meth)acrylic acid esters (e.g., 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2- trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, etc.), alkylaminoalkyl (meth)acrylate acrylates (eg, dimethylaminoethyl (meth)acrylate, etc.), and the like. These (meth)acrylates can be used alone or in combination of two or more. Specific examples of the acrylic oligomer (E) include "ARUFON" manufactured by Toagosei Co., Ltd., "ACT FLOW" manufactured by Soken Chemical Co., Ltd., and "JONCRYL" manufactured by BASF Japan.

The amount of the acrylic oligomer compounded is usually preferably 15 parts by weight or less with respect to 100 parts by weight of the total amount of the monomer components in the curable resin composition. If the content of the acrylic oligomer in the composition is too high, the reaction rate when the composition is irradiated with an active energy ray will decrease significantly, resulting in poor curing in some cases. On the other hand, in order to sufficiently suppress curing shrinkage of the adhesive layer, the composition preferably contains 3 parts by weight or more of the acrylic oligomer.

The curable resin composition preferably contains a photopolymerization initiator. A photopolymerization initiator is appropriately selected depending on the active energy ray. When curing with ultraviolet light or visible light, a photopolymerization initiator that is cleaved with ultraviolet light or visible light is used. Examples of the photopolymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3′-dimethyl-4-methoxybenzophenone; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2 -propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenylketone and other aromatic ketone compounds; methoxyacetophenone, 2,2-dimethoxy- Acetophenone compounds such as 2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin methyl ether, Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; aromatic ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl) oxime; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4- Thioxanthone compounds such as dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; camphorquinone; halogenated ketone; acylphosphinoxide; acylphosphonate, and the like.

The blending amount of the photopolymerization initiator is 20 parts by weight or less with respect to 100 parts by weight of the total amount of the polymerizable compound A. The blending amount of the photopolymerization initiator is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, further preferably 0.1 to 5 parts by weight.

In addition, when the curable resin composition is used as a visible light-curable type, it is preferable to use a photopolymerization initiator that is particularly sensitive to light of 380 nm or more. A photopolymerization initiator highly sensitive to light of 380 nm or more will be described later.

As the photopolymerization initiator, a compound represented by the following general formula (1);

(wherein R ¹ and R ² represent —H, —CH ₂ CH ₃ , —iPr or Cl, and R ¹ and R ² may be the same or different), or the general formula ( It is preferable to use the compound represented by 1) together with a photopolymerization initiator highly sensitive to light of 380 nm or longer, which will be described later. When the compound represented by the general formula (1) is used, the adhesiveness is superior to that when a photopolymerization initiator highly sensitive to light of 380 nm or more is used alone. Among the compounds represented by general formula (1), diethylthioxanthone in which R ¹ and R ² are —CH ₂ CH ₃ is particularly preferred. The composition ratio of the compound represented by general formula (1) in the curable resin composition is preferably 0.1 to 5% by weight, preferably 0.5 to 5% by weight, based on the total amount of the curable resin composition. It is more preferably 4% by weight, and even more preferably 0.9 to 3% by weight.

In addition, it is preferable to add a polymerization initiation aid as necessary. Examples of polymerization initiation aids include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate. and ethyl 4-dimethylaminobenzoate is particularly preferred. When a polymerization initiation aid is used, the amount added is usually 0 to 5% by weight, preferably 0 to 4% by weight, most preferably 0 to 3% by weight, based on the total amount of the curable resin composition. .

In addition, a known photopolymerization initiator can be used together as needed. Since the transparent protective film having UV absorbability does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator that is highly sensitive to light of 380 nm or more. Specifically, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 , 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole- 1-yl)-phenyl) titanium and the like.

The curable resin composition preferably contains a silane coupling agent. Specific examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycide as active energy ray-curable compounds. xypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane silane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and the like.

　Preferred are 2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane.

The amount of the silane coupling agent is preferably in the range of 0.01 to 20% by mass, preferably 0.05 to 15% by mass, and 0.1 to 10% by mass with respect to the total amount of the adhesive composition. % is more preferred. This is because if the amount exceeds 20% by mass, the storage stability of the adhesive composition deteriorates, and if the amount is less than 0.1% by mass, the effect of adhesive water resistance is not sufficiently exhibited.

Specific examples of non-active energy ray-curable silane coupling agents other than the above include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltrimethoxysilane. silane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatopropyltriethoxysilane, imidazolesilane, and the like.

The curable resin composition, if necessary, further contains a compound according to the following general formula (3);

(where X is a functional group containing a reactive group, R ⁶ and R ⁷ are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an aryl group, or a heterocyclic group represents), preferably a compound according to the general formula (3′);

(where Y is an organic group, X' is a reactive group contained in X, and R ⁶ and R ⁷ are the same as described above), more preferably the following general formulas (3a) to (3d) Compound;

can be incorporated into the adhesive composition. When these compounds are blended in the adhesive composition, the adhesiveness to the polarizer and the transparent protective film may be improved, which is preferable. From the viewpoint of improving the adhesiveness and water resistance between the polarizer and the transparent protective film, the content of the compound represented by the general formula (3) in the curable water-dispersible composition is 0.001 to 50% by mass. preferably 0.1 to 30% by mass, most preferably 1 to 10% by mass.

In the general formula (3), the aliphatic hydrocarbon group is a linear or branched alkyl group which may have a substituent having 1 to 20 carbon atoms, and a substituent having 3 to 20 carbon atoms. cyclic alkyl groups which may be substituted, and alkenyl groups having 2 to 20 carbon atoms. optionally substituted naphthyl groups and the like, and examples of heterocyclic groups include 5- or 6-membered ring groups containing at least one heteroatom and optionally having substituents. These may be linked together to form a ring. In general formula (3), R ⁶ and R ⁷ are preferably a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms, most preferably a hydrogen atom.

X possessed by the compound represented by the general formula (3) is a functional group containing a reactive group, which is a functional group capable of reacting with the curable component constituting the adhesive layer, and the reactive group contained in X is is, for example, hydroxyl group, amino group, aldehyde group, carboxyl group, vinyl group, (meth)acryl group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, α,β-unsaturated carbonyl groups, mercapto groups, halogen groups, and the like. When the curable resin composition constituting the adhesive layer is active energy ray-curable, the reactive group contained in X is a vinyl group, a (meth)acryl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, X is preferably at least one reactive group selected from the group consisting of an epoxy group, an oxetane group and a mercapto group, especially when the adhesive composition constituting the adhesive layer is radically polymerizable. The reactive group is preferably at least one reactive group selected from the group consisting of a (meth)acryl group, a styryl group and a (meth)acrylamide group, and the compound represented by the general formula (1) is When having a (meth)acrylamide group, the reactivity is high and the copolymerization rate with the active energy ray-curable resin composition is increased, which is more preferable. In addition, the (meth)acrylamide group has a high polarity and is excellent in adhesiveness, so that the effect of the present invention can be efficiently obtained. When the curable resin composition that constitutes the adhesive layer is cationic polymerizable, the reactive group contained in X is a hydroxyl group, an amino group, an aldehyde, a carboxyl group, a vinyl ether group, an epoxy group, an oxetane group, or a mercapto group. It is preferable to have at least one selected functional group, especially when it has an epoxy group, it is preferable for excellent adhesion between the resulting curable resin layer and the adherend, and when it has a vinyl ether group, the curable resin composition is preferred because of its excellent curability.

In the present invention, the compound represented by the general formula (3) may be one in which the reactive group and the boron atom are directly bonded. The compound represented by is preferably one in which a reactive group and a boron atom are bonded via an organic group, that is, a compound represented by general formula (3′). For example, when the compound represented by the general formula (3) is bonded to a reactive group via an oxygen atom bonded to a boron atom, the adhesive water resistance of the polarizing film tends to deteriorate. On the other hand, the compound represented by the general formula (3) does not have a boron-oxygen bond, but has a boron-carbon bond and contains a reactive group by bonding a boron atom and an organic group. When it is a compound (when represented by general formula (3′)), it is preferable because the adhesive water resistance of the polarizing film is improved. The organic group specifically means an organic group having 1 to 20 carbon atoms which may have a substituent, and more specifically, for example, having a substituent having 1 to 20 carbon atoms. A linear or branched alkylene group which may be optionally substituted, a cyclic alkylene group which may have a substituent of 3 to 20 carbon atoms, a phenylene group which may have a substituent of 6 to 20 carbon atoms, a phenylene group which may have a substituent of 10 to 10 carbon atoms. A naphthylene group which may have 20 substituents may be mentioned.

As the compound represented by the general formula (3), in addition to the compounds exemplified above, esters of hydroxyethylacrylamide and boric acid, esters of methylolacrylamide and boric acid, esters of hydroxyethyl acrylate and boric acid, and hydroxybutyl Esters of (meth)acrylates and boric acid can be exemplified, such as esters of acrylate and boric acid.

The cationically polymerizable compound used in the cationically polymerizable curable resin composition includes a monofunctional cationically polymerizable compound having one cationically polymerizable functional group in the molecule and two or more cationically polymerizable functional groups in the molecule. It is classified into polyfunctional cationic polymerizable compounds with Since the monofunctional cationically polymerizable compound has a relatively low liquid viscosity, the liquid viscosity can be reduced by including it in the cationically polymerizable curable resin composition. In addition, the monofunctional cationically polymerizable compound often has a functional group that exhibits various functions. Various functions can be expressed in the cured product of the curable resin composition. Since the polyfunctional cationically polymerizable compound can three-dimensionally crosslink the cured product of the cationically polymerizable curable resin composition, it is preferably contained in the cationically polymerizable curable resin composition. The ratio of the monofunctional cationically polymerizable compound and the polyfunctional cationically polymerizable compound is such that 100 parts by weight of the monofunctional cationically polymerizable compound is mixed with 10 parts by weight to 1000 parts by weight of the polyfunctional cationically polymerizable compound. is preferred. Examples of cationic polymerizable functional groups include epoxy groups, oxetanyl groups, and vinyl ether groups. Compounds having an epoxy group include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds. It is particularly preferred to contain an alicyclic epoxy compound. Alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, caprolactone-modified products of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and trimethylcaprolactone-modified products. and modified valerolactone, and specifically, Celoxide 2021, Celoxide 2021A, Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085 (manufactured by Daicel Chemical Industries, Ltd., Cyracure UVR-6105, Cyracure UVR -6107, Cyracure 30, R-6110 (manufactured by Dow Chemical Japan Co., Ltd.), etc. Compounds having an oxetanyl group improve the curability of the cationic polymerizable adhesive composition, Compounds having an oxetanyl group include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanyl ) methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, di[(3-ethyl-3-oxetanyl)methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, phenol Aron oxetane OXT-101, Aron oxetane OXT-121, Aron oxetane OXT-211, Aron oxetane OXT-221, Aron oxetane OXT-212 (manufactured by Toagosei Co., Ltd.) and the like are commercially available. A compound having a vinyl ether group has the effect of improving the curability of the cationic polymerizable adhesive composition and lowering the liquid viscosity of the composition, and is therefore preferably contained. , 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, cyclohexanedimethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether , ethoxyethyl vinyl ether, pentaerythritol type tetravinyl ether, and the like.

The cationically polymerizable curable resin composition contains at least one compound selected from the epoxy group-containing compound, the oxetanyl group-containing compound, and the vinyl ether group-containing compound described above as a curable component. A photo cationic polymerization initiator is blended because it is cured by This cationic photopolymerization initiator generates cationic species or Lewis acid upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays and electron beams, and initiates the polymerization reaction of epoxy groups and oxetanyl groups. As the photocationic polymerization initiator, a photoacid generator described later is preferably used. Further, when the cationic polymerizable adhesive composition is used with visible light curing, it is preferable to use a cationic photopolymerization initiator that is particularly sensitive to light of 380 nm or more. Since it is a compound that exhibits maximum absorption in a wavelength region near or shorter than 300 nm, by blending a photosensitizer that exhibits maximum absorption in a wavelength region longer than that, specifically, light with a wavelength longer than 380 nm, this It can respond to light of a wavelength in the vicinity and promote the generation of cationic species or acid from the photocationic polymerization initiator. Examples of photosensitizers include anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, and the like. You may use it in mixture of 2 or more types. Anthracene compounds are particularly preferable because of their excellent photosensitizing effect, and specific examples thereof include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Kasei Co., Ltd.). The content of the photosensitizer is preferably 0.1 wt % to 5 wt %, more preferably 0.5 wt % to 3 wt %.

The polarizing film according to the present invention is produced by, for example, the following production method;
A polarizer manufacturing step of manufacturing a polarizer in which a non-polarizing portion having a concave portion on one side is formed by treating a predetermined position on one surface of the polarizer with a treatment liquid, and the polarizer has the concave portion. A coating step of applying a curable resin composition to the surface, a bonding step of bonding a transparent protective film to the surface of the polarizer coated with the curable resin composition, a polarizer surface side or a transparent and a bonding step of bonding the polarizer and the transparent protective film via an adhesive layer obtained by curing the curable resin composition by irradiating the active energy ray from the protective film surface side. It can be manufactured by a method for manufacturing a polarizing film. The polarizer manufacturing process includes a first step of temporarily attaching a surface protective film having through holes to one surface of the polarizer to form a polarizing film laminate, and through the through holes of the surface protective film. a second step of treating a predetermined position on one surface of the polarizer with a treatment liquid to form a non-polarizing portion having a recess on one surface; and a third step of peeling and removing the surface protective film from the polarizer. It may have a step.

The method of applying the curable resin composition to the surface of the polarizer having recesses is appropriately selected depending on the viscosity of the composition and the desired thickness. Therefore, it is preferable to use the post-metering coating method. Specific examples of the post-metering coating method include gravure roll coating, forward roll coating, air knife coating, and rod/bar coating. Among these, the gravure roll coating method is particularly preferable from the viewpoint of the removal of foreign substances on the surface of the transparent protective film and the coatability.

Before the coating step, an easy-adhesive composition may be coated on the adhesive composition-coated surface of the polarizer. As a method for applying the easy-adhesive composition to the bonding surface of the polarizer, it is preferable to use a post-metering coating method because the same effects as in the coating step are obtained. When the easy-adhesion composition contains the compound represented by the general formula (3), the adhesive strength between the polarizer and the transparent protective film is increased, which is preferable.

In the gravure roll coating method, various patterns can be formed on the surface of the gravure roll, such as a honeycomb mesh pattern, a trapezoidal pattern, a grid pattern, a pyramid pattern, or a diagonal line pattern. In order to effectively prevent appearance defects of the finally obtained polarizing film, the pattern formed on the surface of the gravure roll is preferably a honeycomb mesh pattern. In the case of a honeycomb mesh pattern, the cell volume is preferably 1 to 5 cm ³ /m ² , more preferably 2 to 3 cm ³ /m ² in order to increase the surface precision of the coated surface after the easy-adhesion composition is applied. is preferred. Similarly, the number of cell lines per inch of the roll is preferably 200 to 3000 lines/inch in order to improve the surface precision of the coated surface after coating with the easy-adhesive composition. Further, it is preferable that the rotation speed ratio of the gravure roll to the traveling speed of the polarizer is 100 to 300%.

The polarizer and the transparent protective film are bonded together via the curable resin composition coated as described above. The bonding of the polarizer and the transparent protective film can be performed using a roll laminator or the like.

After bonding the polarizer and the transparent protective film together, they are irradiated with active energy rays (electron beams, ultraviolet rays, visible rays, etc.) to cure the curable resin composition and form an adhesive layer. The irradiation direction of the active energy rays (electron beam, ultraviolet rays, visible rays, etc.) can be any suitable direction. Preferably, irradiation is performed from the transparent protective film side. When irradiated from the polarizer side, the polarizer may be deteriorated by active energy rays (electron beams, ultraviolet rays, visible rays, etc.).

Any appropriate irradiation conditions can be adopted as long as the conditions are such that the curable resin composition can be cured when the electron beam is irradiated. For example, electron beam irradiation preferably has an acceleration voltage of 5 kV to 300 kV, more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the adhesive, resulting in insufficient curing. may give The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. If the irradiation dose is less than 5 kGy, the adhesive will be insufficiently cured, and if it exceeds 100 kGy, the transparent protective film and polarizer will be damaged, the mechanical strength will decrease and yellowing will occur, and the desired optical properties will not be obtained. can't

　Electron beam irradiation is usually carried out in an inert gas, but if necessary, it may be carried out in the air or with a small amount of oxygen introduced. Although it depends on the material of the transparent protective film, by appropriately introducing oxygen, the surface of the transparent protective film that is exposed to the electron beam first is intentionally inhibited by oxygen, and damage to the transparent protective film can be prevented. Efficient electron beam irradiation can be achieved.

In the method for producing a polarizing film, it is preferable to use, as the active energy ray, an active energy ray containing visible light with a wavelength range of 380 nm to 450 nm, particularly an active energy ray with the highest irradiation amount of visible light with a wavelength range of 380 nm to 450 nm. . In the case of using ultraviolet rays and visible rays, when using a transparent protective film imparted with ultraviolet absorption ability (ultraviolet-impermeable transparent protective film), it absorbs light with a wavelength shorter than about 380 nm. Light of that wavelength does not reach the adhesive composition and does not contribute to its polymerization reaction. Furthermore, light with a wavelength shorter than 380 nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, causing defects such as curling and wrinkling of the polarizing film. Therefore, when ultraviolet light and visible light are used in the present invention, it is preferable to use a device that does not emit light with a wavelength shorter than 380 nm as an active energy ray generator, and more specifically, an integrated wavelength range of 380 to 440 nm. The ratio of illuminance to integrated illuminance in the wavelength range of 250 to 370 nm is preferably 100:0 to 100:50, more preferably 100:0 to 100:40. In the method for producing a polarizing film according to the present invention, a gallium-encapsulated metal halide lamp and an LED light source emitting light in a wavelength range of 380 to 440 nm are preferable as active energy rays. Alternatively, ultraviolet rays from low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, extra high pressure mercury lamps, incandescent lamps, xenon lamps, halogen lamps, carbon arc lamps, metal halide lamps, fluorescent lamps, tungsten lamps, gallium lamps, excimer lasers, or sunlight. A light source containing visible light can be used, and a band-pass filter can be used to cut off ultraviolet light with a wavelength shorter than 380 nm. In order to prevent the curling of the polarizing film while improving the adhesion performance of the adhesive layer between the polarizer and the transparent protective film, a gallium-filled metal halide lamp is used, and light with a wavelength shorter than 380 nm can be blocked. It is preferable to use an active energy ray obtained through a bandpass filter or an active energy ray with a wavelength of 405 nm obtained using an LED light source.

It is preferable to heat the adhesive composition before irradiation with ultraviolet light or visible light (heating before irradiation), in which case the temperature is preferably 40°C or higher, more preferably 50°C or higher. preferable. It is also preferable to heat the active energy ray-curable adhesive composition after irradiation with ultraviolet light or visible light (post-irradiation heating). Warming is more preferred.

The polarizing film of the present invention can be used as an optical film laminated with other optical layers in practical use. The optical layer is not particularly limited. One or more optical layers may be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film obtained by further laminating a reflector or a semi-transmitting reflector on the polarizing film of the present invention, an elliptical polarizing film or circularly polarized light obtained by further laminating a retardation plate on the polarizing film A film, a wide viewing angle polarizing film obtained by further laminating a viewing angle compensation film on a polarizing film, or a polarizing film obtained by further laminating a brightness enhancement film on a polarizing film are preferable.

The optical film obtained by laminating the above optical layer on the polarizing film can be formed by a method of sequentially and separately laminating in the manufacturing process of an image display device or the like. It is excellent in stability and assembly work, and has the advantage of being able to improve the manufacturing process of image display devices and the like. Appropriate adhesive means such as an adhesive layer can be used for lamination. When the above polarizing film and other optical films are adhered, their optical axes can be arranged at an appropriate angle according to the desired retardation characteristics.

The above-mentioned polarizing film and optical film laminated with at least one layer of polarizing film can also be provided with an adhesive layer for adhering to other members such as liquid crystal cells. The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer is not particularly limited, but for example, an acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based polymer, rubber-based polymer, or the like is appropriately selected. can be used as In particular, those having excellent optical transparency, suitable wettability, cohesiveness, and adhesive properties such as acrylic pressure-sensitive adhesives, and excellent weather resistance and heat resistance can be preferably used.

The adhesive layer can also be provided on one or both sides of the polarizing film or optical film as a superimposed layer of different compositions or types. Further, when the adhesive layer is provided on both sides, the front and back surfaces of the polarizing film or the optical film may have adhesive layers with different compositions, types, thicknesses, and the like. The thickness of the adhesive layer can be appropriately determined according to the purpose of use, adhesive strength, etc., and is generally 1 to 100 μm, preferably 5 to 30 μm, particularly preferably 10 to 20 μm.

The exposed surface of the adhesive layer is temporarily covered with a separator for the purpose of preventing contamination until it is put into practical use. This prevents contact with the adhesive layer during normal handling conditions. As the separator, excluding the above thickness conditions, suitable thin sheets such as plastic films, rubber sheets, paper, cloth, non-woven fabrics, nets, foam sheets, metal foils, and laminates thereof may be used. An appropriate release agent according to the prior art, such as one coated with an appropriate release agent such as chain alkyl, fluorine, or molybdenum sulfide, can be used.

[Image display device]
The polarizing film of the present invention can be preferably used for forming various devices such as image display devices. Formation of the image display device can be carried out according to the conventional method. That is, an image display device is generally formed by appropriately assembling components such as a liquid crystal cell, a polarizing film or an optical film, and an illumination system as necessary, and incorporating a driving circuit. There is no particular limitation except that the polarizing film or optical film according to the invention is used, and conventional methods can be applied. As for the liquid crystal cell, any type such as TN type, STN type, or π type can be used.

Appropriate image display devices can be formed, such as an image display device in which a polarizing film or an optical film is arranged on one or both sides of a liquid crystal cell, or a device using a backlight or a reflector in an illumination system. In that case, the polarizing film or optical film according to the present invention can be placed on one side or both sides of the liquid crystal cell. When polarizing films or optical films are provided on both sides, they may be the same or different. Furthermore, when forming an image display device, for example, appropriate parts such as a diffusion plate, an anti-glare layer, an antireflection film, a protection plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, etc. Two or more layers can be arranged. Furthermore, examples of the image display device of the present invention include an organic EL (electroluminescence) display device, a PDP (plasma display panel), an electronic paper, and the like. be done. In addition, as for the application of the image display device, it can be preferably applied to the application that requires a member that is required to have durability characteristics in a high humidity and heat environment, such as a foldable display device and a vehicle display device.

Since the polarizing film according to the present invention has a non-polarizing portion formed on the polarizer, it can be suitably used particularly for an image display device having a sensor function. placed in corresponding positions.

Examples of the present invention are described below, but embodiments of the present invention are not limited to these.

<Polarizing film manufacturing>
Example 1
As the resin substrate, a long amorphous isophthalic acid-copolymerized polyethylene terephthalate (IPA-copolymerized PET) film (thickness: 100 μm) with a water absorption of 0.75% and a Tg of 75° C. was used. One side of the substrate was subjected to corona treatment, and the corona-treated side was coated with polyvinyl alcohol (degree of polymerization: 4,200, degree of saponification: 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization: 1,200, degree of acetoacetyl modification: 4.6). %, degree of saponification 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOSEFIMER Z200") at a ratio of 9:1. A PVA-based resin layer was formed to produce a laminate.

The resulting laminate was uniaxially stretched 2.4 times at the free end in the machine direction (longitudinal direction) between rolls with different peripheral speeds in an oven at 120°C (in-air auxiliary stretching). Next, the laminate was immersed in an insolubilizing bath (an aqueous boric acid solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 30° C. for 30 seconds (insolubilizing treatment). Then, it was immersed in a dyeing bath at a liquid temperature of 30° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 parts by weight of iodine was added to 100 parts by weight of water, and 1.5 parts by weight of potassium iodide was added to the resulting iodine aqueous solution for 60 seconds (dyeing treatment). . Next, it was immersed for 30 seconds in a cross-linking bath at a liquid temperature of 30°C (an aqueous boric acid solution obtained by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water). (crosslinking treatment). After that, the laminate is immersed in an aqueous solution of boric acid having a liquid temperature of 70° C. (an aqueous solution obtained by blending 3 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water). Meanwhile, the film was uniaxially stretched in the machine direction (longitudinal direction) between rolls with different circumferential speeds so that the total draw ratio was 5.5 (underwater stretching). After that, the laminate was immersed in a cleaning bath having a liquid temperature of 30° C. (aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).

Subsequently, a radically polymerizable curable resin composition is applied to the second transparent protective film, and the PVA-based resin layer surface of the laminate obtained above and the radically polymerizable curable resin composition coated surface of the second transparent protective film are were laminated together, and the following ultraviolet rays were irradiated from the second transparent protective film side to cure the adhesive.

After that, the substrate was peeled off from the PVA-based resin layer to obtain a long polarizing film (polarizer/second transparent protective film) with a width of about 1300 mm. The polarizer had a thickness of 5 μm and a single transmittance of 40.8%.

(ultraviolet rays)
As an active energy ray, ultraviolet rays (gallium-filled metal halide lamp, irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc., bulb: V bulb, peak illuminance: 1600 mW/cm ² , cumulative irradiation amount 1000/mJ/cm ² (wavelength 380-440 nm)) was used. The UV illuminance was measured using a Sola-Check system manufactured by Solatell.

An adhesive (acrylic adhesive) was applied to one side of an ester resin film (thickness: 38 μm) with a width of about 1,300 mm so that the thickness would be 5 μm. Through-holes having a diameter of 3.0 mm were formed in this adhesive-attached ester resin film at intervals of 250 mm in the longitudinal direction and at intervals of 400 mm in the width direction using a Pycnal blade.

On the polarizer side of the polarizing film obtained above, the adhesive-attached ester resin film is laminated by roll-to-roll, and this is immersed in a 1 mol / L (1N) sodium hydroxide aqueous solution for 30 seconds, and then , and immersed in 1 mol/L (1N) hydrochloric acid for 10 seconds. Then, it dried at 60 degreeC and formed the non-polarization part in the polarizer. The non-polarizing portion was a thin portion having a concave portion with a maximum depth dh of 0.5 μm on the side of the ester resin film.

The ester-based resin film was peeled off from the laminate obtained above. Subsequently, before bonding the release surface of the ester resin film of the laminate to the first transparent protective film, the easy-adhesion composition 1 is applied to the release surface using a gravure roll coating method equipped with a gravure roll. (coating thickness: 1 μm), and air-dried at 25° C. for 1 minute (thickness after drying: 0.7 μm). Subsequently, adhesive composition 1 is applied to an acrylic resin film (thickness 40 μm) as a first transparent protective film, and the peeling surface (coated surface of easy-adhesion composition 1) of the ester resin film of the laminate is laminated. , UV rays similar to those described above were applied from the acrylic resin film side to cure the adhesive. Table 1 shows the configurations of Adhesive Composition 1 and Easy Adhesive Composition 1. Table 2 shows the thickness of the adhesive layer after curing.

Each constituent material described in Table 1 is as follows.
ACMO (acryloylmorpholine); trade name "ACMO", 1,9-NDA (1,9-nonanediol diacrylate) manufactured by KJ Chemicals, trade name "Light acrylate 1,9ND-A", P2H manufactured by Kyoeisha Chemical Co., Ltd. -A (phenoxydiethylene glycol acrylate); trade name "Light Acrylate P2H-A", Kyoeisha Chemical Co., Ltd. HEAA (hydroxyethyl acrylamide); trade name "HEAA", BYK UV3505 (UV curable surface conditioner) manufactured by Kojin Co., Ltd.; Trade name "BYK UV3505", manufactured by BYK Chemie Japan Or907 (2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one); trade name "Omnirad 907", manufactured by IGMresins DETX (diethylthioxanthone); trade name "KAYACURE DETX-S", manufactured by Nippon Kayaku Co., Ltd. UP-1190 (acrylic oligomer obtained by polymerizing (meth)acrylic monomer); trade name "ARUFON UP1190", manufactured by Toagosei Co., Ltd. Or819 (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide); trade name "Omnirad 819", IGM
VPBA (4-vinylphenylboronic acid); trade name "4-vinylphenylboronic acid", manufactured by Tokyo Chemical Industry Co., Ltd. HPAA (hydroxypivalic acid diacrylate); trade name "light acrylate HPPA", manufactured by Kyoeisha Chemical Co., Ltd. M5700 (2 -hydroxy-3-phenoxypropyl acrylate); trade name "Aronix M5700", DEAA (diethylacrylamide) manufactured by Toagosei Co., Ltd.; trade name "DEAA", EXP4200 manufactured by KJ Chemicals (leveling agent); trade name "OLFINE EXP.4200 , manufactured by Nissin Chemical Industry Co., Ltd.

A polarizing film having a configuration of the first transparent protective film/polarizer was produced as described above. The first transparent protective film corresponds to the transparent protective film 3 constituting the polarizing film 10 shown in FIG. 1, the polarizer corresponds to the polarizer 1 constituting the polarizing film 10 shown in FIG. The adhesive layer that adheres the protective film and the polarizer corresponds to the adhesive layer 2 that constitutes the polarizing film 10 shown in FIG. Table 2 shows the thickness of the obtained polarizing film and the measurement results of each physical property.

In Table 2, the thickness d1 (μm) of the non-polarizing portion of the polarizer and the thickness d2 (μm) of the portion of the adhesive layer in contact with the non-polarizing portion were measured using a scanning electron microscope (manufactured by ZYGO, product name “New View 7300"). The thickness d3 (μm) of the first transparent protective film was measured using a digital micrometer (manufactured by Anritsu Co., Ltd., product name "KC-351C").

In Table 2, the hardness H1 (GPa) of the non-polarized portion, the hardness H2 (GPa) of the portion of the adhesive layer in contact with the non-polarized portion, and the hardness H3 (GPa) of the transparent protective film were measured by the following methods. did.

Using a nanoindenter (Triboindenter TI-950, manufactured by Bruker Japan), the center of each part of the polarizing film to be measured (for example, when measuring the hardness H1 of the non-polarized part, the center of the non-polarized part, When measuring the hardness H3 of the transparent protective film, a Berkovich type indenter (manufactured by Bruker Japan Co., Ltd., Triboindenter TI-950 indenter (model number TI-0039; Berkovich type diamond The maximum load (Pmax) and the area of contact between the indenter and the measurement part (contact projected area) (A) when the indenter and the tip opening angle of 142.3°) are pushed by 50 nm are measured. (GPa) was calculated.
(Hardness (GPa)) = (Pmax) / (A)

In Table 2, the dimensional shrinkage rate X1 of the polarizing film containing the non-polarizing portion 1A was measured by the following method.
<Measurement of dimensional shrinkage>
An adhesive layer was provided on the transparent protective film side of the polarizing film of Example 1 to prepare a polarizing film with an adhesive layer. Using a CO ₂ laser (manufactured by Comnet Co., Ltd., product name: Laser Pro-SPIRIT), the non-polarized portion 1A (the non-polarized portion has a circular shape with a diameter of 3 mm) is formed at a position of 1 cm from the center end. A polarizing film with an agent layer (sample size: 10 cm x 10 cm) was cut out and attached to non-alkaline glass having a thickness of 0.5 mm to prepare a sample. The focal lengths (MD direction and TD direction) of the four corners of the sample were measured using a plane biaxial measuring device (manufactured by Mitutoyo Corporation, product name: Quick Vision Apex). Then, the laminate was left in an environment of 85° C. and 85% humidity for 72 hours, and the focal lengths (MD direction and TD direction) of the four corners of the optical laminate were similarly measured. Based on the dimensions before and after the standing, the dimensional shrinkage rate X1 of the polarizing film including the non-polarizing portion 1A was calculated. Table 2 shows the dimensional shrinkage in the MD direction where the dimensional shrinkage is large. The irradiation conditions of the _CO2 laser are as follows.
(Irradiation conditions)
Wavelength: 10.6 μm
Laser output: 30W
Oscillation mode: Pulse oscillation Diameter of laser beam: 70 μm Laser irradiation surface: Protective film side

As shown in Table 2, in Example 1, the dimensional shrinkage rate X1 of the polarizing film containing the non-polarizing portion 1A is low, and the dimensional stability of the non-polarizing portion 1A is high, so that the optical function is excellent even under high temperature and high humidity. Understand.

<Polarizing film manufacturing>
Example 2-6
As the resin substrate, a long amorphous isophthalic acid-copolymerized polyethylene terephthalate (IPA-copolymerized PET) film (thickness: 100 μm) with a water absorption of 0.75% and a Tg of 75° C. was used. One side of the substrate was subjected to corona treatment, and the corona-treated side was coated with polyvinyl alcohol (degree of polymerization: 4,200, degree of saponification: 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization: 1,200, degree of acetoacetyl modification: 4.6). %, degree of saponification 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOSEFIMER Z200") at a ratio of 9:1. A PVA-based resin layer was formed to produce a laminate.

After that, the substrate was peeled off from the PVA-based resin layer to obtain a long polarizing film (polarizer/second transparent protective film) with a width of about 1300 mm. In Examples 2-6 and Comparative Example 1, the thickness of the polarizer was 5 μm, and the single transmittance was 40.8%. On the other hand, in Comparative Example 2, the thickness of the polarizer was 4 μm, and the single transmittance was 40.8%.

Among the constituent materials listed in Table 3, materials other than the constituent materials listed in Table 1 are as follows.
VPBA (4-vinylphenylboronic acid); trade name "4-vinylphenylboronic acid", manufactured by Tokyo Chemical Industry Co., Ltd.

In Table 3, in Comparative Examples 1 and 2, a water-based adhesive (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOSEFIMER Z-200", resin concentration 5) was used as the adhesive composition constituting the first adhesive layer. % and water content of 95% by weight).

On the polarizer side of the polarizing film obtained above, the adhesive-attached ester resin film was laminated by roll-to-roll. The obtained polarizing film of Examples 2-6 was treated under the treatment conditions shown in Table 3 to produce a polarizing film having a polarizer in which non-polarizing portions having different thicknesses and hardnesses were formed. Regarding the treatment conditions described in Table 3, "NaOH treatment time" is the time (seconds) during which the polarizing film was immersed in a 1 mol/L (1N) sodium hydroxide aqueous solution, and "HCl treatment time" is 1 mol/ The time (seconds) during which the polarizing film was immersed in L (1N) hydrochloric acid, and "drying temperature" means the drying temperature (°C) after NaOH treatment and HCl treatment.

The ester-based resin film was peeled off from the laminate obtained above. Subsequently, with regard to Example 6, before bonding the release surface of the ester resin film of the laminate to the first transparent protective film, the release surface was easily coated using a gravure roll coating method equipped with a gravure roll. The adhesive composition 1 was applied (coating thickness: 1 μm) and air-dried at 25° C. for 1 minute (thickness after drying: 0.7 μm). Subsequently, each adhesive composition shown in Table 3 was applied to the first transparent protective film shown in Table 3, and for Examples 2-5, the coated surface of each adhesive composition of the transparent protective film and the laminate The release surface of the ester resin film, and in Example 6, the coated surface of each adhesive composition of the transparent protective film and the coated surface of the easy-adhesion composition 1 were respectively laminated, and the same ultraviolet rays as described above were irradiated from the transparent protective film side. Allow the adhesive to cure. Table 3 shows the thickness of the adhesive layer after curing.

Films (1) to (5) constituting the first transparent protective film shown in Table 3 are shown below.
Film (1); acrylic resin film manufactured by Toyo Kohan Co., Ltd. (thickness: 20 µm)
Film (2): Acrylic resin film manufactured by Toyo Kohan Co., Ltd. (thickness: 30 μm)
Film (3): Zeonor-based resin film manufactured by Zeon (thickness: 17 μm)
Film (4): Acrylic resin film manufactured by Toyo Kohan Co., Ltd. (thickness: 40 μm)
Film (5): Triacetyl cellulose resin film manufactured by Konica Minolta (thickness: 40 μm)

<Polarizing film manufacturing>
Comparative Example 1-2
A water-based adhesive (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “GOSEFIMER Z-200”, resin concentration 5% by weight and water content 95% by weight) was used so that the thickness of the adhesive layer after heating was 0.1 μm. PVA-based resin aqueous solution) was applied to the first transparent protective film shown in Table 3, attached to the release surface of the ester-based resin film, and heated in an oven maintained at 80°C for 5 minutes. The viscosity of the water-based adhesive before curing was 10 mPa·s.

A polarizing film having a configuration of the first transparent protective film/polarizer was produced as described above. The first transparent protective film corresponds to the transparent protective film 3 constituting the polarizing film 10 shown in FIG. 1, the polarizer corresponds to the polarizer 1 constituting the polarizing film 10 shown in FIG. The adhesive layer that adheres the protective film and the polarizer corresponds to the adhesive layer 2 that constitutes the polarizing film 10 shown in FIG. Table 3 shows the thickness of the obtained polarizing film and the measurement results of each physical property.

In Table 3, the thickness d1 (μm) of the non-polarizing portion of the polarizer, the thickness d2 (μm) of the portion in contact with the non-polarizing portion of the adhesive layer, the thickness d3 (μm) of the first transparent protective film, the non-polarizing portion hardness H1 (GPa) of the adhesive layer, hardness H2 (GPa) of the portion in contact with the non-polarizing portion of the adhesive layer, and hardness H3 (GPa) of the transparent protective film, dimensional shrinkage of the polarizing film containing the non-polarizing portion 1A X1 was measured and evaluated in the same manner as in Example 1. In Table 3, the fact that the dimensional shrinkage rate of Comparative Example 2 is negative means that the polarizing film expanded after being left in an environment of 85° C. and 85% humidity for 72 hours.

<Evaluation of image distortion>
The polarizing films of Example 1-6 and Comparative Example 1-2 were left in an environment of 85° C. and 85% humidity for 72 hours. After being left standing, the pitch between lattices in the periphery of the non-polarizing portion of the transmitted output image when projecting an input image having grid-like lines on the non-polarizing portion of each polarizing film is increased or decreased. The presence or absence of distortion caused by It means that the less distortion, the better the optical function of the polarizing film even under high temperature and high humidity. ◎ indicates the case where almost no distortion was observed, ○ indicates that the peripheral portion of the non-polarized portion of the transmitted image appears somewhat curved, but is of a practical level, and × indicates that the peripheral portion appears greatly distorted. show.

As shown in Tables 2 and 3, in Example 2-6, the dimensional shrinkage rate X1 of the polarizing film containing the non-polarizing portion 1A is low, and the dimensional stability of the non-polarizing portion 1A is high. It can be seen that it is superior to

Claims

A polarizing film in which a transparent protective film is laminated via an adhesive layer on at least one surface of a polarizer,
The polarizer has a non-polarizing portion formed at least in part,
A polarizing film, wherein the dimensional shrinkage rate X1 of the polarizing film containing the non-polarizing portion after being left in an environment of 85° C. and 85% humidity for 72 hours is 1.0% or less.
When the hardness of the non-polarizing portion is H1 (GPa) and the thickness of the non-polarizing portion is d1,
H1×d1≧0.8
The polarizing film according to claim 1.
When the hardness of the transparent protective film is H3 (GPa) and the moisture permeability of the transparent protective film is T3 (g/m 2 ),
H3×T3<50
The polarizing film according to claim 1.
When the hardness of the portion of the adhesive layer in contact with the non-polarizing portion is H2 (GPa) and the thickness is d2 (μm),
H2×d2≧0.20
The polarizing film according to claim 1.
The polarizing film according to claim 1, wherein the thickness of the adhesive layer between the portion of the polarizer other than the non-polarizing portion and the transparent protective film is 2 µm or less.
An image display device comprising the polarizing film according to claim 1, wherein the non-polarizing portion of the polarizing film is arranged at a position corresponding to the sensor portion.