TW201807031A - Flexible polarizing film, manufacturing method for same and image display device - Google Patents

Abstract

The present invention relates to a flexible polarizing film comprising a polyvinyl alcohol polarizer, not thicker than 10[mu]m, in which polyvinyl alcohol resin is orientated in one direction and iodine or a dichromatic pigment is adsorbed and orientated on the polyvinyl alcohol resin, wherein the flexible polarizing film exhibits no breaking, traces of cracking or light-loss in either direction after being subjected to a U-shape flexing test in which the film is repeatedly flexed into a U-shape in the orientation direction in which the polyvinyl alcohol resin is orientated and the direction orthogonal to the orientation direction. The flexible polarizing film according to the present invention has a high level of flexibility despite using a polyvinyl alcohol polarizer.

Description

Flexible polarizing film, manufacturing method thereof, and image display device

FIELD OF THE INVENTION The present invention relates to a flexible polarizing film and a method for manufacturing the same. The flexible polarizing film may be used alone or as an optical film formed by laminating the flexible polarizing film to form an image display device such as a liquid crystal display device (LCD) or an organic EL display device.

BACKGROUND OF THE INVENTION For a liquid crystal display device, according to its image formation method, it is indispensable to arrange polarizers on both sides of a glass substrate forming the surface of a liquid crystal panel. The polarizer is generally a polyvinyl alcohol-based polarizer made of polyvinyl alcohol-based resin aligned in one direction and the polyvinyl alcohol-based resin adsorbed and aligned with iodine or a dichroic dye. However, the polyvinyl alcohol-based polarizer has a problem that the monomer is weak and easily broken. In particular, the polyvinyl alcohol-based polarizer is easily broken in parallel in the direction in which the polyvinyl alcohol-based resin is aligned (the direction of the absorption axis). For example, when an external force is applied to shrink it in the direction of the absorption axis, it is very easy to break.

Therefore, polyvinyl alcohol-based polarizers are generally used in the form of a polarizing film with a transparent protective film pasted on one or both sides.

In addition to polyvinyl alcohol-based polarizers, grating polarizers are also known as other polarizers (Patent Documents 1 and 2). Prior Art Literature Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2005-316495 Patent Document 2: Japanese Patent Application Laid-Open No. 2007-232792

SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, in general, a polarizing film using a polyvinyl alcohol-based polarizer is pasted with a transparent protective film, so it has rigidity (resilience) and lacks flexibility (flexibility). Therefore, when the polarizing film is twisted, cracks or residual folding marks (creases) are generated in the entire film, or light leakage occurs in the polarizer, which limits its usefulness. On the other hand, although grating polarizers are flexible, they lack versatility.

An object of the present invention is to provide a flexible polarizing film having a high degree of flexibility even though a polyvinyl alcohol-based polarizer is used, and a method for producing the same.

Another object of the present invention is to provide an image display device having the flexible polarizing film. Means to solve the problem

As a result of intensive research by the inventors of the present case, it was found that the above-mentioned problems can be solved by the following flexible polarizing film and the like, and the present invention has been achieved.

That is, the present invention relates to a flexible polarizing film, which is characterized in that it has a polyvinyl alcohol-based polarizer with a thickness of 10 μm or less, and the polyvinyl alcohol-based polarizer is oriented in one direction with the polyvinyl alcohol resin and the polyvinyl alcohol is The resin is adsorbed and aligned with iodine or dichroic pigment, and when the flexible polarizing film is subjected to a bending retention test, the flexible polarizing film is held in an orientation direction of the polyvinyl alcohol resin orientation and a direction orthogonal to the orientation direction. After bending, the bending shape can be maintained in any direction without cracks.

When the flexible polarizing film is subjected to a torsion test, it is preferable that the flexible polarizing film is free of cracks, creases, and light leakage after being twisted in the direction in which the polyvinyl alcohol-based resin is aligned.

When the flexible polarizing film is subjected to a bending retention test, the flexible polarizing film can be maintained in a bent shape in either direction after being bent in an orientation direction of the polyvinyl alcohol-based resin alignment and a direction orthogonal to the alignment direction. It is advisable to produce cracks.

When the flexible polarizing film is subjected to a stiffness test to the orientation direction of the polyvinyl alcohol-based resin alignment and a direction orthogonal to the orientation direction, the stiffness (mm) is preferably 60 mm or less.

In the tensile test of the flexible polarizing film, a tensile strength in a direction orthogonal to an alignment direction of the polyvinyl alcohol-based resin alignment is preferably 5 N / 10 mm or more.

It is preferable that the flexible polarizing film is composed of the polyvinyl alcohol-based polarizer system so that the optical characteristics represented by the single transmittance T and the polarization degree P satisfy the following formula: P ＞-(10 ^0.929T-42.4 -1 ) × 100 (but T <42.3), or P ≧ 99.9 (but T ≧ 42.3).

The flexible polarizing film preferably has a reinforcing film on at least one side of the polyvinyl alcohol-based polarizer, which is in close contact with the polyvinyl alcohol-based polarizer. The thickness of the aforementioned reinforcing film is preferably 15 μm or less.

The flexible polarizing film is preferably a first reinforcing film having a thickness of 15 μm or less on a first side of the polyvinyl alcohol-based polarizer, and a second reinforcing film having a thickness of 15 μm or less on a second side of the other side. The thickness difference between the first reinforcing film and the second reinforcing film is preferably 10 μm or less.

In the flexible polarizing film, the ratio of the thickness of the reinforcing film to the thickness of the polyvinyl alcohol-based polarizer is preferably 0.4 or more.

In the flexible polarizing film, the compression elastic coefficient of the reinforcing film at 23 ° C. is preferably 1 MPa or more.

As the flexible polarizing film, the reinforcing film may be used without being substantially aligned.

As the flexible polarizing film, a resin film can be used as the reinforcing film. The resin film is preferably a formed product of a thermosetting resin or an active energy ray curing resin.

In addition, the present invention relates to a method for manufacturing a flexible polarizing film, which is the aforementioned method for manufacturing a flexible polarizing film, and includes the following steps: (1) preparing a polyvinyl alcohol-based polarizer having a thickness of 10 μm or less, the polyvinyl alcohol The polarizer is a polyvinyl alcohol-based resin aligned in one direction and the polyvinyl alcohol-based resin is adsorbed and aligned with iodine or a dichroic pigment; and step (2), at least one side of the polyvinyl alcohol-based polarizer After a liquid material containing a resin component or a curable component constituting a resin film is applied, the liquid material is cured or hardened to form a reinforcing film.

The present invention also relates to an image display device using the flexible polarizing film. Invention effect

The flexible polarizing film of the present invention adopts a polyvinyl alcohol-based polarizer, which can satisfy versatility. In addition, the thickness of the polyvinyl alcohol-based polarizer is 10 μm or less, and it is also ideal for thinning.

Furthermore, although the flexible polarizing film of the present invention uses a polyvinyl alcohol-based polarizer that is fragile and easily broken, it still has a high degree of flexibility. Even if the shape is deformed by twisting, it will not cause cracks or residues on the entire film Fold traces (creases) or cause light leakage to the aforementioned polarizer. In addition, the flexible polarizing film of the present invention has flexibility in response to various deformations such as expansion and contraction. In this way, when a general polyvinyl alcohol-based polarizer is a single body, the tensile fracture stress will be significantly reduced and it will not be able to operate substantially. In contrast, the flexible polarizing film of the present invention not only has the flexibility of the polarizing film itself, but also Thin thickness and good operability.

In addition, the flexible polarizing film of the present invention exhibits flexibility, and has flexibility when used in conjunction with or bonded to other members. Therefore, it is possible to suppress cracks in the polarizer, and it can be used for various applications. Therefore, the use of the flexible polarizing film alone can be greatly expanded by expanding the use of the flexible polarizing film alone or by increasing the allowable range in the manufacturing process. Therefore, the flexible polarizing film of the present invention can be used as a substitute for polarizers, for example, in the past, the polarizers are fragile and easy to break and cannot be applied to the design, or can be used as polarizing films (those with transparent protective films on the polarizers) The alternatives are applied to various deformed shapes that were previously unsuitable due to the rigidity of the polarizing film, and are intended for expansion.

Means for Solving the Invention The flexible polarizing film of the present invention will be described below. The flexible polarizing film of the present invention includes a polyvinyl alcohol-based polarizer.

<Polyvinyl alcohol-based polarizer> The polyvinyl alcohol-based polarizer is oriented in one direction (absorption axis direction), and the polyvinyl alcohol-based resin is adsorbed and aligned with iodine or a dichroic pigment. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, partially formalized polyvinyl alcohol, and ethylene saponified vinyl acetate copolymer-based partial saponification. The polarizer can be obtained by allowing a polyvinyl alcohol-based film using the aforementioned polyvinyl alcohol-based resin to adsorb iodine or a dichroic dye of a dichroic dye and uniaxially stretch it.

For example, polyvinyl alcohol can be dipped in an iodine aqueous solution to be dyed and stretched 3 to 7 times its original length to produce a polarizer made of a polyvinyl alcohol film that is dyed with iodine or a dichroic pigment and uniaxially stretched. It can contain boric acid, zinc sulfate, zinc chloride, etc. as required, or it can be immersed in an aqueous solution such as potassium iodide. If necessary, the polyvinyl alcohol film can be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, dirt and an anti-adhesive agent on the surface of the polyvinyl alcohol-based film can be cleaned. In addition, the polyvinyl alcohol-based film can swell to prevent unevenness such as staining. Stretching can be performed after dyeing with iodine or dichroic pigment, and it can be extended while dyeing, or it can be stretched and then dyed with iodine or dichroic pigment. Extension can also be performed in an aqueous solution such as boric acid or potassium iodide or in a water bath.

The point that the polyvinyl alcohol-based polarizer contains boric acid is quite suitable from the viewpoint of elongation stability and optical durability. From the viewpoint of suppressing light leakage, the content of boric acid in the polarizer is preferably 25% by weight or less, more preferably 20% by weight or less, more preferably 18% by weight or less, and 16% by weight or less relative to the total amount of the polarizer. It's better. On the other hand, from the viewpoint of the elongation stability and optical durability of the polarizer, the boric acid content is preferably 10% by weight or more, more preferably 12% by weight or more, relative to the total amount of the polarizer.

In the present invention, a polyvinyl alcohol-based polarizer having a thickness of 10 μm or less is used. When the thickness of the polyvinyl alcohol-based polarizer exceeds 10 μm, it is difficult to obtain sufficient flexibility. From the viewpoint of thinning and flexibility, the thickness of the polarizer is preferably 8 μm or less, more preferably 7 μm or less, and even more preferably 6 μm or less. The thickness of the polarizer is 2 μm or more, and more preferably 3 μm or more. Such thin polarizers have small thickness variations, good visibility, and small dimensional changes, so they have excellent durability against thermal shock.

Examples of thin polarizers include thin polarizers described in the following documents, or thin polarizers made by the manufacturing methods described in these: Japanese Patent No. 4751486, Japanese Patent No. 4751481, and Japanese Patent No. 4815544. No. 5, Japanese Patent No. 5048120, International Publication No. 2014/077599, International Publication No. 2014/077636.

The aforementioned polarizer is configured such that the optical characteristics represented by the single transmittance T and the polarization degree P satisfy the following formula: P>-(10 ^0.929T-42.4 -1) × 100 (however, T <42.3), or P ≧ 99.9 (however, T ≧ 42.3). In short, a polarizer configured to meet the aforementioned conditions has the performance required for a liquid crystal television display using a large display element. Specifically, the contrast is 1000: 1 or more and the maximum brightness is 500cd / m ² or more. For other uses, for example, it can be attached to the viewing side of an organic EL display device.

On the other hand, a polarizer made up of the aforementioned conditions exhibits a high degree of alignment because the polymer (such as a polyvinyl alcohol-based molecule) constitutes it, so it is compatible with a thickness of 10 μm or less and orthogonal to the direction of the absorption axis of the polarizer The tensile fracture stress in the direction (transmission axis direction) will be significantly reduced. As a result, for example, a general polarizing film is likely to cause light leakage in the direction of the absorption axis of the polarizer. Although the flexible polarizing film of the present invention uses such a polyvinyl alcohol-based polarizer having a thickness of 10 μm or less, it has excellent flexibility.

In the manufacturing method including the step of stretching in the state of a laminated body and the dyeing step, from the viewpoint of being able to stretch at high magnification and improve the polarization performance, the aforementioned thin polarizers are described in, for example, Japanese Patent No. 4751486 and Japanese Patent No. 4751481. Those described in the specification and Japanese Patent No. 4815544 are preferably prepared by a method including an extension step in an aqueous boric acid solution, and are particularly included as described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544. It is suitable to obtain the method by performing the step of auxiliaryly performing aerial stretching in the boric acid aqueous solution before stretching. These thin polarizers can be produced by a manufacturing method including the following steps: a step of stretching a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) layer and a resin substrate for stretching in a laminated state and a dyeing step . In this manufacturing method, even if the PVA-based resin layer is very thin, it can be stretched by the support of the stretching resin substrate, and there is no problem such as breakage caused by stretching.

In addition, the flexible polarizing film of the present invention is characterized in that it can maintain a bent shape and no cracks after a bending holding test shown in Examples is specifically performed. The bending retention test shows that the flexible polarizing film can be maintained in its original state even when it is bent and bent in the alignment direction (absorption axis direction) and the orthogonal direction (transmission axis direction) of the polyvinyl alcohol resin alignment. Retention-related softness index. It can be seen that the flexible polarizing film of the present invention has excellent retention in both the absorption axis direction and the transmission axis direction by maintaining the folded shape and suppressing cracks in the bending retention test.

After the flexible polarizing film of the present invention is specifically subjected to the torsion test shown in the examples, it is preferable to suppress the occurrence of cracks, creases, and light leakage of the polyvinyl alcohol-based polarizer. The torsion test shows a polyvinyl alcohol-based resin that is prone to cracks, creases, and light leakage, and is an index of flexibility when it is twisted in the alignment direction (absorption axis direction) of the row alignment. It is understood that the flexible polarizing film of the present invention is free from cracks, creases, and light leakage in a torsion test, and has excellent flexibility in a torsion state.

In addition, the flexible polarizing film of the present invention should preferably suppress the occurrence of cracks, creases, and light leakage after performing the U-shaped stretching test shown in the embodiment. The U-shaped stretch test is a softness index related to the bending property of the U-shaped line without load in the alignment direction (absorption axis direction) and the orthogonal direction (transmission axis direction) of the alignment of the polyvinyl alcohol resin. It can be seen that the flexible polarizing film of the present invention has excellent unloaded bending flexibility in both directions of the absorption axis direction and the transmission axis direction by suppressing the occurrence of cracks, creases, and light leakage in the U-shaped stretching test.

The flexible polarizing film of the present invention preferably satisfies a rigidity (mm) of 60 mm or less in the rigidity and softness test shown in the specific embodiment. The rigidity and softness test is a softness index related to bending tracking (low resistance to bending) of the alignment direction (absorption axis direction) and orthogonal direction (transmission axis direction) of the orientation of the polyvinyl alcohol resin. The flexible polarizing film of the present invention is found to have a stiffness of 60 mm or less and has flexibility related to bendability (low resistance to bending). The rigidity (mm) is an index that exhibits the softness, and is preferably 50 mm or less, and more preferably 40 mm or less. In addition, the lower limit of the stiffness (mm) is not particularly limited.

The flexible polarizing film of the present invention preferably satisfies a tensile strength of 5 N / 10 mm or more in the tensile test shown in the specific embodiment. The tensile test is an index showing the strength in the direction (transmission axis direction) orthogonal to the alignment direction (absorption axis direction) of the polyvinyl alcohol-based resin alignment. It can be seen that the flexible polarizing film of the present invention has strength in the transmission axis direction by satisfying the aforementioned tensile strength of 5N / 10 mm or more. From the viewpoint of strength, the tensile strength is preferably 7 N / 10 mm or more, and more preferably 10 N / 10 mm or more.

An example of the flexible polarizing film of the present invention is described below with reference to FIG. 1. As the flexible polarizing film of the present invention, for example, a material having a reinforcing film on at least one side of a polyvinyl alcohol-based polarizer can be used. The flexible polarizing film 1 in FIG. 1 (A) is a case where only the first side of the polyvinyl alcohol-based polarizer a has the first reinforcing film b1. In addition, the flexible polarizing film 1 shown in FIG. 1 (B) is a case where the first side of the polyvinyl alcohol-based polarizer 1 has the first reinforcing film b1 and the second side of the other side has the second reinforcing film b2. In the flexible polarizing film 1 of the present invention, the first reinforcing film b1 and / or the second reinforcing film b2 are directly provided on the aforementioned polyvinyl alcohol-based polarizer 1.

The flexible polarizing film 1 of the present invention has the flexibility of the aforementioned torsion test, and is obviously different from a polarizing film that cannot meet the aforementioned flexibility, such as a transparent protective film on one or both sides of the polyvinyl alcohol-based polarizer a. .

<Reinforcing film> From the viewpoint of thinning and flexibility, the thickness of the reinforcing film is preferably 15 μm or less, more preferably 10 μm or less, and even more preferably 7 μm or less. From the viewpoint of flexibility and strength, the thickness of the reinforcing film is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more.

From the viewpoint of flexibility and strength, the ratio (t2 / t1) of the reinforcing film thickness (t2) to the thickness (t1) of the polyvinyl alcohol-based polarizer is preferably 0.4 or more, preferably 0.6 or more, and 0.8 or more good. On the other hand, from the viewpoint of thinning, the aforementioned ratio (t2 / t1) is preferably 2.0 or less, more preferably 1.5 or less, and more preferably 1.2 or less.

The aforementioned reinforcing film is compared with the case where only the polyvinyl alcohol-based polarizer 1 has the first reinforcing film b1 on one side as shown in FIG. 1 (A), and the polyvinyl alcohol-based polarizer shown in FIG. 1 (B) The case where both sides have the first reinforcing film b1 and the second reinforcing film b2 satisfies the flexibility of the aforementioned bending retention test, torsion test, U-shaped stretch test, etc., and the strength of the tensile test is satisfied, so it is suitable.

As shown in Figure 1 (B), when the polyvinyl alcohol-based polarizer 1 has the first reinforcing film b1 and the second reinforcing film b2 on both sides, the thickness of each reinforcing film may be the same or different from each other. In the case where the body is left standing) and the flexibility test (various tests such as a bending retention test), the stress in the flexible polarizing film is balanced (symmetrical) to make it easier to ensure the strength and flexibility. The thickness difference between the reinforcing film b1 and the second reinforcing film b2 is preferably 10 μm or less, preferably 7 μm or less, more preferably 5 μm or less, and the same thickness is particularly preferable.

From the viewpoint of strength, the compression elastic coefficient of the aforementioned reinforcing film at 23 ° C is preferably 1 MPa or more. In addition, the compression elastic coefficient of the aforementioned reinforcing film is preferably 10 MPa or more, and more preferably 100 MPa or more. On the other hand, if the compressive elastic coefficient of the reinforcing film layer is too large, it will become too hard and tend to deteriorate in softness. Therefore, the compressive elastic coefficient is preferably 10 GPa or less, and more preferably 1 GPa or less.

The reinforcing film may be formed from various forming materials. The reinforcing film can be formed by, for example, applying a resin material to a polyvinyl alcohol-based polarizer, or can be formed by depositing an inorganic oxide such as SiO ₂ on the polyvinyl alcohol-based polarizer by a sputtering method or the like. From the viewpoint of easy formation, the reinforcing film is preferably a resin film formed of a resin material.

The aforementioned reinforcing film may be used with or without alignment. If the aforementioned reinforcing film is aligned, a phase difference will occur and the optical characteristics of the polyvinyl alcohol-based polarizer will be changed. Therefore, when maintaining the optical characteristics of the aforementioned polarizing member, it is preferable to use a substantially unaligned reinforcing film. Substantially unaligned refers to a state in which, although there is an alignment inside the reinforcing film due to the alignment of the polarizer, the process of performing the alignment of the reinforcing film is not actively performed. The reinforcing film without alignment is formed, for example, by coating a resin film forming material on a polyvinyl alcohol-based polarizer. On the other hand, as the aforementioned reinforcing film, an aligned object may be used. The aligned reinforcing film can show a phase difference, and can also be used as an optical compensation film.

The material for forming the aforementioned reinforcing film is not particularly limited as long as it can adhere to the polyvinyl alcohol-based polarizer, and examples thereof include polyester resins, polyether resins, polycarbonate resins, and polyurethane resins. Resins, silicone resins, polyamide resins, polyimide resins, PVA resins, acrylic resins, epoxy resins, etc. These resin materials may be used singly or in combination of two or more. Among them, they are selected from the group consisting of polyurethane resins, PVA resins, acrylic resins, and epoxy resins. One or more members of the group are preferred, and polyurethane resins and acrylic resins are preferred.

The reinforcing film may be formed by applying a liquid material containing the resin component or a curable component constituting a resin on the surface of the polarizer, and then curing or curing the liquid material. In addition, the form of the coating liquid of the liquid substance is not particularly limited as long as it is liquid, and it can be selected from water-based, water-dispersed, solvent-based, and solvent-free.

Moreover, the said formation material may contain an additive in the range which does not impair the function of a reinforcement film. For example, powders such as polyether compounds such as silane coupling agents and polypropylene glycols, colorants, and pigments, dyes, surfactants, plasticizers, tackifiers, and antistatic agents can be appropriately added depending on the application. , Surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, granules, foils, etc. In addition, a redox system with a reducing agent can be used within a controllable range.

It is advantageous that the liquid (coating liquid) has a low viscosity. The aforementioned viscosity is preferably 2000 mPa ℃ s or less measured at 25 ° C, more preferably 1000 mPa ･ s or less, more preferably 500 mPa ･ s or less, and even more preferably 100 mPa ･ s or less.

When forming the said reinforcing film, after applying the liquid substance containing the said resin component, this resin component should be hardened by the kind. The liquid material containing the resin component is a solution or dispersion in which the resin component is dissolved or dispersed in a solvent, and it can be used, for example, in the form of an aqueous solution, a water-dispersed dispersion, or a solvent-based solution. The curing is a process of removing a solvent from the liquid to form a resin layer.

In addition, when forming the transparent resin layer, a liquid substance containing a curable component constituting the resin should be applied, and then the curable component should be applied in accordance with the type of the curable component to harden the resin. As long as the liquid material containing the curable component which can constitute the said resin is a liquid material, the said curable component can be used without a solvent type. As the liquid substance, a solution in which the hardening component is dissolved in a solvent can be used. Moreover, when the said hardening component is liquid, it can also be used as a solution. The solvent can be appropriately selected depending on the hardening component used. For example, when an acrylic monomer forming an acrylic resin or an epoxy monomer forming an epoxy resin is used as the curable component, the liquid material containing the curable component can be irradiated with active energy rays (irradiation UV) and so on.

As the aqueous dispersion, a water-based resin latex can be used. The aqueous resin latex contains latex resin particles emulsified in water (dispersion medium). The reinforcing film of the present invention can be formed by directly applying the forming material containing the aforementioned aqueous resin latex to a polarizer and drying it.

The resin constituting the latex resin is not particularly limited, and examples thereof include an acrylic resin, a silicone resin, a polyurethane resin, and a fluorine resin. In the present invention, from the viewpoint of excellent optical transparency and excellent weather resistance, heat resistance, etc., among these, polyurethane resins and acrylic resins are preferred.

Examples of the aforesaid water-based resin latex include a trade name manufactured by TAISEI FINE CHEMICAL CO, .LTD .: SE-2915E (acrylic latex containing a UV absorbing material), and a trade name manufactured by Toa Kosei Corporation: Aron A-104, Aron A-106, and the like.

Next, the reinforcing film will be described as a hardening type forming material containing a hardening component that can constitute a resin. The hardening component can be roughly classified into active energy ray hardening type and heat hardening type such as electron beam hardening type, ultraviolet hardening type, and visible light hardening type. In addition, ultraviolet curing type and visible light curing type can be divided into radical polymerization curing type and cation polymerization curing type. In the present invention, an active energy ray with a wavelength range of 10 nm to 380 nm is denoted as ultraviolet light, and an active energy ray with a wavelength range of 380 nm to 800 nm is denoted as visible light. The said radical polymerization hardening type hardening component can be used as a thermosetting type hardening component.

≪Radical Polymerization Hardening Forming Material≫ Examples of the curable component include a radical polymerizable compound. Examples of the radically polymerizable compound include compounds having a radically polymerizable functional group having a carbon-carbon double bond such as a (meth) acrylfluorenyl group and a vinyl group. As these hardening components, a monofunctional radically polymerizable compound or a difunctional or more multifunctional radically polymerizable compound can be optionally used. Moreover, these radically polymerizable compounds may be used individually by 1 type, and may use 2 or more types together. The radical polymerizable compound is preferably a compound having a (meth) acrylfluorenyl group, for example. In the present invention, (meth) acrylfluorenyl means acrylfluorenyl and / or methacrylfluorenyl, and the following "(meth)" is the same.

≪ Monofunctional radical polymerizable compound ≫ As a monofunctional radical polymerizable compound, a (meth) acrylamido derivative having a (meth) acrylamido group is mentioned. The (meth) acrylamide derivative is suitable because it can ensure the adhesion to the polarizer, and has a high polymerization speed and good productivity. Specific examples of the (meth) acrylamide derivative include N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl ( N-alkyl-containing (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, etc. Meth) acrylamide derivatives; N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamine, N-hydroxymethyl-N-propane (meth) acrylamine N-hydroxyalkyl-containing (meth) acrylamide derivatives, such as amines; amine methyl (meth) acrylamide, amine ethyl (meth) acrylamine, etc. (Meth) acrylamide derivatives; N-alkoxy-containing (meth) acrylamide derivatives such as N-methoxymethacrylamine, N-ethoxymethacrylamine; mercaptomethyl N-mercaptoalkyl-containing (meth) acrylamide derivatives such as (meth) acrylamide and mercaptoethyl (meth) acrylamide and the like. Examples of the heterocyclic ring-containing (meth) acrylamide derivative in which the nitrogen atom of the (meth) acrylamino group forms a heterocyclic ring include N-acrylamide morpholin, N-acrylamine piperidine, N- Methacrylic acid piperidine, N-acrylic acid pyrrolidine and the like.

Among the (meth) acrylamide derivatives, an N-hydroxyalkyl-containing (meth) acrylamide derivative is preferred from the standpoint of adhesion with a polarizer, and N-hydroxyethyl ( Methacrylamide is particularly preferred.

Examples of the monofunctional radical polymerizable compound include various (meth) acrylic acid derivatives having a (meth) acrylic fluorenyloxy group. Specific examples include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and 2-methyl-2-nitropropyl (Meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, secondary butyl (meth) acrylate, tertiary butyl (meth) acrylate, (meth) acrylic acid N-pentyl ester, tertiary amyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, ( Hexadecyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, (methyl ) (Meth) acrylic acid (carbon number 1-20) alkyl esters such as n-octadecyl acrylate.

Examples of the (meth) acrylic acid derivative include cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate and cyclopentyl (meth) acrylate; benzyl (meth) acrylate and the like ( Aralkyl meth) acrylate; 2-Isofluorenyl (meth) acrylate, 2-norbornyl methyl (meth) acrylate, 5-norbornen-2-yl-methyl (methyl) ) Acrylate, 3-methyl-2-norbornyl methyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, Polycyclic (meth) acrylates such as dicyclopentyl (meth) acrylate; 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxy Methyl methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ecarbitol (meth) acrylate, phenoxyethyl (meth) acrylate, alkyl Alkoxy or phenoxy-containing (meth) acrylates and the like, such as phenoxy polyethylene glycol (meth) acrylate.

Examples of the (meth) acrylic acid derivative include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and (meth) 2-hydroxybutyl acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate , 12-hydroxylauryl (meth) acrylate, hydroxyalkyl (meth) acrylate or [4- (hydroxymethyl) cyclohexyl] methacrylate, cyclohexanedimethanol dry (meth) acrylate , 2-hydroxy-3-phenoxypropyl (meth) acrylate and other hydroxyl-containing (meth) acrylates; glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate ring Epoxy-containing (meth) acrylates such as oxypropyl ether; 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethylethyl (meth) acrylate Ester, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptafluorodecyl (meth) acrylate, 3-chloro Halogenated (meth) acrylates such as -2-hydroxypropyl (meth) acrylate; alkylamines such as dimethylamine ethyl (meth) acrylate (Meth) acrylate; 3-oxetanylmethyl (meth) acrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl- Oxetanyl methyl (meth) acrylate, 3-butyl-oxetanyl methyl (meth) acrylate, 3-hexyl-oxetanyl methyl (methyl ) Oxygen-containing cyclobutane (meth) acrylates such as acrylates; tetrahydrofurfuryl (meth) acrylate, (meth) acrylates such as butyrolactone (meth) acrylate, and (meth) acrylates having a heterocyclic ring or hydroxytris Neopentyl glycol (meth) acrylic acid adduct of methyl acetate, p-phenylphenol (meth) acrylate, and the like.

Examples of the monofunctional radical polymerizable compound 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 the monofunctional radically polymerizable compound include endomeramine-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, Vinyl piperidone, vinylpyrimidine, vinyl piperidine Vinylpyridine , Vinylpyrrole, vinylimidazole, ethylene Vinyl monomers having nitrogen-containing heterocycles, such as azole and vinylmorpholin.

As the monofunctional radical polymerizable compound, a radical polymerizable compound having a living methylene group can be used. A radically polymerizable compound having an active methylene group is a compound having an active methylene group such as an active double bond group such as a (meth) acrylfluorenyl group in a terminal or a molecule. Examples of the active methylene group include acetamidine, alkoxypropylamidine or cyanoacetamidine. The aforementioned active methylene group is preferably ethylamidine. Specific examples of the radically polymerizable compound having an active methylene group include 2-acetamethyleneacetoxyethyl (meth) acrylate, 2-acetamethyleneacetoxypropyl (meth) acrylate, Acetylethoxyalkyl (meth) acrylates such as 2-ethenylethoxy-1-methylethyl (meth) acrylate; 2-ethoxypropionyloxyethyl ( (Meth) acrylate, 2-cyanoethoxyethyl (meth) acrylate, N- (2-cyanoethoxyethyl) acrylamidonium, N- (2-propanylethyl) Ethoxybutyl) acrylamide, N- (4-ethylammoniumethoxymethylbenzyl) acrylamide, N- (2-ethylammoniumethylammonylethyl) acrylamide, and the like. As the radically polymerizable compound having a living methylene group, acetoacetoxyalkyl (meth) acrylate is preferable.

≪Polyfunctional radical polymerizable compound≫ In addition, examples of the difunctional or more polyfunctional radical polymerizable compound 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 adduct di (meth) acrylate, bisphenol A propylene oxide adduct di (meth) acrylic acid Ester, bisphenol A diglycidyl ether di (meth) acrylate, neopentyl glycol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, cyclic trimethylol Propane formal (meth) acrylate, di Alkanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, neopentaerythritol tri (meth) acrylate, neopentaerythritol tetra (meth) acrylate, dineopent Esters of (meth) acrylic acid and polyhydric alcohols such as tetraol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, EO modified diglycerol tetra (meth) acrylate, etc .; 9,9-bis [4- (2- (meth) propenyloxyethoxy) phenyl] fluorene. Specific examples include Aronix M-220, M-306 (manufactured by Toa Synthetic Corporation), 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 (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer), and the like. According to other requirements, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, or various (meth) acrylate-based monomers can be cited.

From the standpoint of having both the adhesiveness and the optical durability of the polarizer, it is preferred that the radical polymerizable compound be used in combination with a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound. Generally, it is suitable to use in combination of 3 to 80% by weight of the monofunctional radical polymerizable compound and 20 to 97% by weight of the polyfunctional radical polymerizable compound with respect to 100% by weight of the radical polymerizable compound.

态 Formation of Radical Polymerization Hardening Forming Material≫ The radical polymerization hardening forming material can be used as an active energy ray hardening type or a thermosetting type forming material. When an electron beam or the like is used as the active energy ray, the active energy ray-curable forming material does not need to contain a photopolymerization initiator, but when ultraviolet rays or visible light is used as the active energy ray, a photopolymerization initiator is preferably contained. In addition, when the curable component is used as the thermosetting component, the forming material preferably contains a thermal polymerization initiator.

≪Photopolymerization Initiator≫ When a radical polymerizable compound is used, the photopolymerization initiator can be appropriately selected according to the active energy ray. When hardened by ultraviolet or visible light, a photopolymerization initiator that is cracked by ultraviolet or visible light can be used. Examples of the photopolymerization initiator include diphenyl ketone compounds such as benzyl, diphenyl ketone, benzoic acid benzoate, 3,3′-dimethyl-4-methoxydiphenyl ketone; 4 -(2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α´-dimethylacetophenone, 2-methyl-2-hydroxypropanebenzene , Α-hydroxycyclohexyl phenyl ketones and other aromatic ketone compounds; methoxyacetanilide, 2,2-dimethoxy-2-phenylacetanilide, 2,2-diethoxyacetanilide , 2-methyl-1- [4- (methylthio) -phenyl] -2-N- Ethyl benzene-based compounds such as phosphonopropane-1; benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, anisin methyl ether Acetoin ether compounds; aromatic ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthylsulfonyl chloride; -(o-ethoxycarbonyl) oxime and other photoactive oxime compounds; 9-oxysulfur , 2-chloro9-oxysulfur 2-methyl 9-oxysulfur 2,4-dimethyl 9-oxosulfur Isopropyl 9-oxysulfur , 2,4-dichloro 9-oxysulfur , 2,4-diethyl 9-oxysulfur 2,4-diisopropyl 9-oxysulfur Dodecyl 9-oxysulfur 9-oxysulfur Compounds; camphorquinone; halogenated ketones; fluorenyl phosphine oxide; fluorenyl phosphonate and the like.

The blending amount of the photopolymerization initiator is 20 parts by weight or less based on 100 parts by weight of the total amount of the curable component (radical polymerizable compound). The blending amount of the photopolymerization initiator is preferably 0.01 to 20 parts by weight, preferably 0.05 to 10 parts by weight, and more preferably 0.1 to 5 parts by weight.

When a visible-light-curing type containing a radical polymerizable compound as a curable component is used as the curing-type forming material, a photopolymerization initiator having a high sensitivity to light of 380 nm or more is particularly preferably used. The photopolymerization initiator having a high sensitivity to light of 380 nm or more will be described in detail later.

The aforementioned photopolymerization initiator is preferably a compound represented by the following general formula (1) alone: [Chemical 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 from each other), or a compound represented by general formula (1) and A photopolymerization initiator with a high sensitivity to light of 380 nm or more is used in combination. When a compound represented by the general formula (1) is used, adhesion is better than when a photopolymerization initiator having a high sensitivity to light of 380 nm or more is used alone. Among the compounds represented by the general formula (1), diethyl 9-oxysulfur wherein R ¹ and R ² are -CH ₂ CH ₃ It's better. The composition ratio of the compound represented by the general formula (1) in the forming material is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, and even more preferably 0.9 to 3 parts by weight with respect to 100 parts by weight of the total amount of the curable component.

Moreover, it is desirable to add a polymerization initiation aid as needed. Examples of polymerization initiation aids include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylamine benzoate, methyl 4-dimethylaminobenzoate, and 4-dimethylamine Ethyl benzoate, isopropyl 4-dimethylaminobenzoate and the like, ethyl 4-dimethylaminobenzoate is particularly preferred. When a polymerization initiation aid is used, the addition amount is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, and most preferably 0 to 3 parts by weight, with respect to 100 parts by weight of the total hardening component.

Moreover, a well-known photoinitiator can be used together as needed. As the photoinitiator, a photoinitiator having a high sensitivity to light of 380 nm or more is preferably used. Specific examples include 2-methyl-1- (4-methylthiophenyl) -2-N- Phenylpropan-1-one, 2-benzyl-2-dimethylamino-1- (4-N- Phenylphenyl) -butanone-1, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4- Phenyl) phenyl] -1-butanone, 2,4,6-tri (methyl) benzylidene-diphenyl-phosphine oxide, bis (2,4,6-tri (methyl) benzene Formamyl) -phenylphosphine oxide, bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl)- Phenyl) titanium and the like.

In particular, in addition to the photopolymerization initiator of the general formula (1), the photopolymerization initiator is more preferably a compound represented by the following general formula (2); [Chemical Formula 2] (In the formula, R ³ , R ^4, and R ⁵ represent -H, -CH ₃ , -CH ₂ CH ₃ , -iPr, or Cl, and R ³ , R ^4, and R ⁵ may be the same or different from each other). As the compound represented by the general formula (2), 2-methyl-1- (4-methylthiophenyl) -2-N-, which is also commercially available, can be suitably used. Porphyrin-1-one (trade name: IRGACURE907, manufacturer: BASF). Others such as 2-benzyl-2-dimethylamino-1- (4-N- Phenylphenyl) -butanone-1 (trade name: IRGACURE369, manufacturer: BASF), 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4 -(4- Phenyl) phenyl] -1-butanone (trade name: IRGACURE379, manufacturer: BASF) is suitable because of its high sensitivity.

<A radically polymerizable compound having an active methylene group and a radical polymerization initiator having a function of extracting hydrogen> In the above-mentioned active energy ray-curable forming material, a radically polymerizable compound having an active methylene group is used as a radical In the case of a polymerizable compound, it is preferably used in combination with a radical polymerization initiator having a hydrogen-extraction effect.

Examples of free radical polymerization initiators with hydrogen extraction are 9-oxysulfur Based radical polymerization initiator, diphenyl ketone based radical polymerization initiator, and the like. The aforementioned radical polymerization initiator is preferably 9-oxysulfur It is a radical polymerization initiator. 9-oxysulfur Examples of the radical polymerization initiator include compounds represented by the general formula (1). Specific examples of the compound represented by the general formula (1) include 9-oxysulfur Dimethyl 9-oxysulfur Diethyl 9-oxysulfur Isopropyl 9-oxysulfur Chlorine 9-oxysulfur Wait. Among the compounds represented by the general formula (1), diethyl 9-oxysulfur wherein R ¹ and R ² are -CH ₂ CH ₃ It's better.

When the active energy ray-curable forming material contains a radically polymerizable compound having an active methylene group and a radical polymerization initiator having a function of extracting hydrogen, the total amount of the curable components should preferably be 100% by weight. 1 to 50% by weight of the aforementioned radically polymerizable compound having an active methylene group, and preferably contains 0.1 to 10 parts by weight of a radical polymerization initiator with respect to 100 parts by weight of the total amount of the curable component.

≪Thermal polymerization initiator≫ The thermal polymerization initiator is preferably one which does not initiate polymerization due to thermal cracking when forming a reinforcing film. For example, a thermal polymerization initiator with a 10-hour half-life temperature of 65 ° C or higher, or even 75 to 90 ° C is preferred. The half-life is an index showing the decomposition rate of the polymerization initiator, and refers to the time when the remaining amount of the polymerization initiator becomes half. The decomposition temperature at which the half-life is obtained within an arbitrary time or the half-life time at any temperature is described in the manufacturer's catalogue, for example, in the "Organic Peroxide Catalogue 9th Edition (2003, May 2003) Month) "and so on.

Examples of the thermal polymerization initiator include lauryl peroxide (10-hour half-life temperature: 64 ° C), peracid benzoyl (10-hour half-life temperature: 73 ° C), 1,1-bis (tertiary butyl peroxy) Group) -3,3,5-tris (methyl) cyclohexane (10-hour half-life temperature: 90 ° C), bis (2-ethylhexyl peroxydicarbonate) (10-hour half-life temperature: 49 ° C), Di (4-tert-butylcyclohexyl) peroxydicarbonate, di-secondary butyl peroxydicarbonate (10-hour half-life temperature: 51 ° C), tert-butyl peroxyneodecanoate (10-hour half-life) Temperature: 48 ° C), trihexyl peroxytrimethylacetate, tert-butyl peroxytrimethylacetate, dilaurin peroxide (10-hour half-life temperature: 64 ° C), di-n-octyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (10-hour half-life temperature: 66 ° C), bis (4-methylbenzylidene) peroxide, peroxide Dibenzidine (10-hour half-life temperature: 73 ° C), tert-butyl peroxyisobutyrate (10-hour half-life temperature: 81 ° C), 1,1-bis (tertiary hexylperoxy) cyclohexane, etc. Organic peroxides.

Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile (10-hour half-life temperature: 67 ° C) and 2,2'-azobis (2-methylbutyronitrile) (10-hour half-life). Temperature: 67 ° C), 1,1-azobis-cyclohexane-1-carbonitrile (10-hour half-life temperature: 87 ° C) and other azo compounds.

The blending amount of the thermal polymerization initiator is 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of the curable component (radical polymerizable compound). The blending amount of the thermal polymerization initiator is preferably 0.05 to 10 parts by weight, and more preferably 0.1 to 3 parts by weight.

≪Cationic polymerization hardening type forming material≫ The hardening component of the cation polymerization hardening type forming material may be a compound having an epoxy group or an oxetanyl group. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various commonly known curable epoxy compounds can be used. For example, a suitable epoxy compound may be a compound (aromatic epoxy compound) having at least two epoxy groups and at least one aromatic ring in the molecule, or having at least two epoxy groups in the molecule and Among them, at least one compound (alicyclic epoxy compound) and the like formed between two adjacent carbon atoms constituting the alicyclic ring.

≪Photocationic Polymerization Initiator≫ The cationic polymerization hardening type forming material contains the epoxy compound and oxycyclobutane compound described above as hardening components, and these can be hardened by cationic polymerization, so a photocationic polymerization initiator can be blended. The photo-cationic polymerization initiator irradiates active energy rays such as visible light, ultraviolet rays, X-rays, and electron rays to generate a cationic species or a Lewis acid to initiate a polymerization reaction of an epoxy group or an oxetanyl group.

<Other components> The hardening type forming material of the present invention preferably contains the following components.

<Acrylic Oligomer> The active energy ray-curable forming material of the present invention may contain an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer in addition to the curable component of the radical polymerizable compound. By including an acrylic oligomer in the active energy ray-curable forming material, the curing shrinkage when the active film is irradiated with the active energy ray to harden it can be reduced, and the interface stress between the reinforcing film and the polarizer can be reduced. In order to sufficiently suppress hardening shrinkage, the content of the acrylic oligomer is preferably 20 parts by weight or less, and more preferably 15 parts by weight or less, based on 100 parts by weight of the total hardening component. When the content of the acrylic oligomer in the forming material is too large, the reaction rate may decrease sharply when the forming material is irradiated with active energy rays, resulting in poor curing. The acrylic oligomer is preferably contained in an amount of 3 parts by weight or more, and more preferably 5 parts by weight or more, based on 100 parts by weight of the total amount of the curable component.

If the workability or uniformity during coating is considered, the active energy ray-curable forming material should have a low viscosity, so the acrylic oligomer obtained by polymerizing a (meth) acrylic monomer should also have a low viscosity. The weight average molecular weight (Mw) of the acrylic oligomer having a low viscosity and capable of preventing the hardening and shrinkage of the reinforcing film is preferably 15,000 or less, preferably 10,000 or less, and particularly preferably 5,000 or less. In addition, in order to sufficiently suppress the curing shrinkage of the reinforcing film, the weight average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1,000 or more, and even more preferably 1500 or more. Specific examples of the (meth) acrylic monomer constituting the acrylic oligomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. Isopropyl ester, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, secondary butyl (meth) acrylate, ( Tertiary butyl (meth) acrylate, n-amyl (meth) acrylate, tertiary amyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (methyl ) Acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propane Alkyl (meth) acrylic acid (1-20 carbon) alkyl esters such as pentyl (meth) acrylate, N-octadecyl (meth) acrylate, etc .; for example, cycloalkane (meth) acrylate Esters (such as cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), aralkyl (meth) acrylates (such as benzyl (meth) acrylate, etc.), polycyclic (methyl ) Acrylates (e.g. 2-isofluorenyl (meth) acrylate, 2-norfluorenylmethyl (meth) propane Acid ester, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornyl methyl (meth) acrylate, etc.), hydroxyl-containing (meth) acrylic acid Esters (e.g. hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (meth) methacrylate, etc.), containing (Meth) acrylates of alkoxy or phenoxy (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxy Ethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ecarbitol (meth) acrylate, phenoxyethyl (meth) acrylate, etc.), ring-containing Oxy (meth) acrylates (e.g., glycidyl (meth) acrylate, etc.), halogenated (meth) acrylates (e.g., 2,2,2-trifluoroethyl (meth) acrylate , 2,2,2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (methyl) Acrylate, heptafluorodecyl (meth) acrylate, etc.), alkylamine alkyl (meth) acrylate (such as dimethylamine ethyl (meth) acrylate, etc.) . These (meth) acrylates can be used alone or in combination of two or more kinds. Specific examples of the acrylic oligomers include "ARUFON" manufactured by Toa Kosei, "Actflow" manufactured by Soken Chemical Co., and "JONCRYL" manufactured by BASF Japan.

<Photoacid generator> The above-mentioned active-energy-ray-curable forming material may contain a photoacid generator. When the photo-acid generator is contained in the active energy ray-curable forming material, the water resistance and durability of the reinforcing film can be dramatically improved compared to the case where the photo-acid generator is not contained. The photoacid generator can be represented by the following general formula (3).

Formula (3) [Chemical Formula 3] (However, L ⁺ represents any cation, and, X ^-. Selected from the group consisting represents _{^{PF6 6 -, SbF 6 -,}} AsF 6 -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 -, disulfide Carbamate anion, SCN ^- Relative anion in the group.)

Specific examples of suitable onium salt constituting the photoacid generator is selected from the group of _{^{PF 6 -, SbF 6 -,}} AsF 6 -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 -, formate anions two thiamin , SCN ^- onium salt composed of anions.

Specifically, suitable specific examples of the photoacid generator include "CYRACURE UVI-6992", "CYRACURE UVI-6974" (manufactured by Dow Chemical Japan Co., Ltd.), "ADEKA OPTOMER SP150", "ADEKA OPTOMER SP152", "ADEKA OPTOMER SP170", "ADEKA OPTOMER SP172" (manufactured by ADEKA Co.), "IRGACURE250" (manufactured by Ciba Specialty Chemicals), "CI-5102", "CI-2855" (manufactured by Soda Corporation of Japan), " "San-aid SI-60L", "San-aid SI-80L", "San-aid SI-100L", "San-aid SI-110L", "San-aid SI-180L" (manufactured by Sanxin Chemical Co., Ltd. above) ), "CPI-100P", "CPI-100A" (manufactured by San-Apro Ltd. above), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI- 044 "," WPI-054 "," WPI-055 "," WPAG-281 "," WPAG-567 "," WPAG-596 "(manufactured by Wako Pure Chemical Industries, Ltd.).

The content of the photoacid generator is 10 parts by weight or less with respect to 100 parts by weight of the total hardening component, preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, and particularly preferably 0.1 to 3 parts by weight.

Forming a reinforcing film using the hardening-type forming material is performed by applying a hardening-type forming material to the surface of a polarizer and curing it.

The polarizer may be subjected to a surface modification treatment before being coated with the hardened forming material. Specific treatments may include, for example, corona treatment, plasma treatment, and saponification treatment.

The coating method of the hardening forming material can be appropriately selected according to the viscosity or the target thickness of the hardening forming material. Examples of coating methods include: reverse coater, gravure coater (direct, reverse or lithographic), bar reverse coater, roll coater, die coating Machine, rod coater, rod coater, and the like. Other methods such as dipping method can be suitably used for coating.

<Hardening of Forming Material> The hardening forming material can be used as an active energy ray hardening forming material or a thermosetting forming material. The active energy ray hardening type forming material can be used in the form of an electron beam hardening type, an ultraviolet hardening type, and a visible light hardening type.

≪Active energy ray hardening type≫ Using an active energy ray hardening type forming material, the active energy ray hardening type forming material is applied to a polarizer, and then the active energy ray (electron rays, ultraviolet rays, visible light, etc.) is irradiated to harden the active energy rays. The forming material hardens to form a reinforcing film. The irradiation direction of active energy rays (electron rays, ultraviolet rays, visible rays, etc.) can be irradiated from any appropriate direction. It should be irradiated from the side of the reinforcing film.

(Electron ray hardening type) In the case of the electron ray hardening type, as long as the conditions for irradiating the electron beam can harden the above-mentioned active energy ray hardening type forming material, any appropriate conditions can be adopted. For example, the acceleration voltage of electron beam irradiation should be 5kV ~ 300kV, more preferably 10kV ~ 250kV. When the acceleration voltage is lower than 5kV, the electron beam may not reach the deepest part of the reinforcing film and there may be insufficient hardening; when the acceleration voltage exceeds 300kV, the penetrating force of the sample may be too strong and the polarizer may be damaged. The radiation dose is 5 ~ 100kGy, more preferably 10 ~ 75kGy. When the irradiation dose is less than 5 kGy, the adhesive will be insufficiently hardened, and if it exceeds 100 kGy, the polarizer will be damaged, resulting in reduced mechanical strength or yellowing, and predetermined optical characteristics cannot be obtained.

Electron beam irradiation is usually performed in an inert gas, but it can also be performed under atmospheric pressure or under conditions where a small amount of oxygen is introduced as required.

≪Ultraviolet hardening type and visible light hardening type≫ Active energy rays should be those containing visible light with a wavelength range of 380nm ~ 450nm, and especially active energy rays with a wavelength range of 380nm ~ 450nm. It is suitable that the active energy ray is sealed with gallium into an LED light source that emits light in a wavelength range of 380 to 440 nm. Or you can use low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, incandescent bulbs, xenon lamps, halogen lamps, carbon arc lamps, metal halide lamps, fluorescent lamps, tungsten lamps, gallium lamps, and excimer-containing lasers. Light sources such as ultraviolet rays and visible rays such as sunlight or sunlight can also be used by bandpass filters to block ultraviolet rays with a wavelength shorter than 380nm.

≪Thermosetting type≫ In addition, the thermosetting type forming material is applied to a polarizer and then heated, and polymerization is initiated by a thermal polymerization initiator to form a cured material layer (reinforcing film). The heating temperature can be set according to the thermal polymerization initiator, such as about 60 ~ 200 ℃, preferably 80 ~ 150 ℃.

As the material for forming the reinforcing film, for example, a cyanoacrylate-based forming material, an epoxy-based forming material, or an isocyanate-based forming material can be used.

Examples of the cyanoacrylate-based forming material include methyl-α-cyanoacrylate, ethyl-α-cyanoacrylate, butyl-α-cyanoacrylate, and octyl-α-cyanoacrylate. Alkyl-α-cyanoacrylate, cyclohexyl-α-cyanoacrylate, methoxy-α-cyanoacrylate, and the like. For example, the cyanoacrylate-based forming material can be used as a user of a cyanoacrylate-based adhesive.

The epoxy-based forming material may be used in the form of an epoxy resin monomer or may contain an epoxy hardener. When an epoxy resin is used as a monomer, a photopolymerization initiator is added, and active energy rays are irradiated to harden it. When an epoxy hardener is added as an epoxy-based forming material, for example, a user who can use it as an epoxy-based adhesive can be used. The use form of the epoxy-based forming material may be a one-liquid type formed by containing an epoxy resin and a hardener thereof, but a two-liquid type in which a hardener is mixed with an epoxy resin is often used. The epoxy-based forming material is usually used as a solution. The solution may be a solvent system or an aqueous system such as a latex, a colloidal dispersion, or an aqueous solution.

Examples of the epoxy resin include various compounds containing two or more epoxy groups in the molecule, such as bisphenol epoxy resin, aliphatic epoxy resin, aromatic epoxy resin, halogenated bisphenol epoxy resin, Biphenyl epoxy resin, etc. The epoxy resin may be appropriately determined depending on the epoxy equivalent or the number of functional groups, and from the viewpoint of durability, it is preferable to use an epoxy equivalent of 500 or less.

The epoxy resin hardener is not particularly limited, and various hardeners such as a phenol resin type, an acid anhydride type, a carboxylic acid type, and a polyamine type can be used. As the phenol resin-based curing agent, for example, phenol novolac resin, bisphenol novolac resin, xylenol resin, cresol novolac resin, and the like can be used. Examples of the acid anhydride-based hardener include maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and succinic anhydride; carboxylic acid-based hardeners include carboxylic acids such as pyromelic acid, trimellitic acid, and vinyl ether. The resulting blocked carboxylic acids. Further, the epoxy-based two-liquid forming material can be, for example, a resin composed of an epoxy resin and a polythiol liquid, or a resin composed of an epoxy resin and a polyamine liquid.

The blending amount of the hardener varies with the equivalent ratio to the epoxy resin, and is preferably 30 to 70 parts by weight, more preferably 40 to 60 parts by weight, relative to 100 parts by weight of the epoxy resin.

Moreover, in addition to an epoxy resin and its hardening | curing agent, various hardening accelerators can also be used for an epoxy-type formation material. Examples of the hardening accelerator include various imidazole compounds and derivatives thereof, and dicyandiamine.

The isocyanate-based forming material may be used as a cross-linking agent when forming an adhesive layer. As the isocyanate-based crosslinking agent, a compound having at least two isocyanate groups can be used. For example, the aforementioned polyisocyanate compound can be used as an isocyanate-based forming material. Specifically, for example, toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, xylylene diisocyanate, and 1,3-bisisocyanatomethylcyclohexyl Alkane, hexamethylene diisocyanate, tetramethylxylene diisocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, methylene bis 4-phenyl isocyanate, diisocyanate Terpolymers such as phenylene esters or dimers thereof or isotrimeric cyanate (6-isocyanate hexyl), in addition, these are reacted with polyhydric alcohols such as biuret or trimethylolpropane and Successor, etc. As the isocyanate-based crosslinking agent, a substance having three or more isocyanate groups such as isotricyanic acid (6-isocyanatehexyl) is preferably used. Examples of the isocyanate-based forming material include an isocyanate-based adhesive.

As far as the present invention is concerned, in the isocyanate-based forming material, it is also preferable to use a rigid structure in which the molecular structure has a cyclic structure (benzene ring, cyanurate ring, trimeric isocyanate ring, etc.) in the structure. . As the isocyanate-based forming material, for example, trimethylolpropane-tri-toluene isocyanate, tris (hexamethylene isocyanate) trimer isocyanate, and the like are preferably used.

As the isocyanate-based crosslinking agent, a terminal isocyanate group-protecting group may be used. Protecting groups include oxime or linacamide. The isocyanate group is protected by heating to dissociate the protective group from the isocyanate group and allow the isocyanate group to react.

In order to improve the reactivity of the isocyanate group, a reaction catalyst may be used. The reaction catalyst is not particularly limited, and a tin-based catalyst or an amine-based catalyst is preferred. The reaction catalyst may be used singly or in combination of two or more kinds. Generally, the amount of the reaction catalyst used can be 5 parts by weight or less based on 100 parts by weight of the isocyanate-based crosslinking agent. When the amount of the reaction catalyst is large, the cross-linking reaction speed will increase and foaming of the forming material will be induced. The use of a foamed forming material cannot provide sufficient adhesion. When a reaction catalyst is generally used, it is preferably 0.01 to 5 parts by weight, and more preferably 0.05 to 4 parts by weight.

Tin-based catalysts can use inorganic and organic systems, but organic systems are preferred. Examples of the inorganic tin-based catalysts include stannous chloride and tin chloride. The organic tin catalyst is preferably a substance having at least one organic group such as an aliphatic group and an alicyclic group having a skeleton such as a methyl group, an ethyl group, an ether group, or an ester group. Examples include tetra-n-butyltin, tri-n-butyltin acetate, n-butyltin trichloride, trimethyltin hydroxide, dimethyltin dichloride, dibutyltin dilaurate, and the like.

The amine catalyst is not particularly limited. For example, to have at least one Organic materials such as alicyclic groups such as pyridine, fluorene, and diazabicycloundecene are preferred. Other amine catalysts include triethylamine. Examples of the reaction catalyst other than the above include cobalt naphthenate and benzyltrimethylammonium hydroxide.

The isocyanate-based forming material is usually used as a solution. The solution may be a solvent system or an aqueous system such as a latex, a colloidal dispersion, or an aqueous solution. The organic solvent is not particularly limited as long as the components constituting the forming material can be uniformly dissolved. Examples of the organic solvent include toluene, methyl ethyl ketone, and ethyl acetate. When an aqueous system is used, alcohols such as n-butanol and isopropanol, and ketones such as acetone may be blended. In the case of an aqueous system, a dispersant can be used to introduce a carboxylic acid salt, a sulfonic acid salt, a quaternary ammonium salt, or a functional group having low reactivity with an isocyanate group or a water-dispersible component such as polyethylene glycol into the isocyanate-based crosslinking agent. .

To form (harden) a reinforcing film by using a cyanoacrylate-based forming material, an epoxy-based forming material, or an isocyanate-based forming material, the type of the forming material may be appropriately selected, and is usually about 30 to 100 ° C and preferably 50 to Dry at 80 ℃ for 0.5 ~ 15 minutes. In the case of the cyanoacrylate-based forming material, since the hardening is fast, the reinforcing film can be formed in a shorter time than the aforementioned time.

As the material for forming the aforementioned reinforcing film, polyurethane can be used. Polyurethane is preferably a high molecular polyol compound and / or a reactant of a low molecular polyol and an isocyanate compound. In addition to the aforementioned polyurethane, in addition to the high-molecular polyol compound and the isocyanate compound, a low-molecular-weight polyamine-based compound and / or a polyol compound can be used as a chain elongator to participate in the reaction.

The polymer polyol compound preferably has a weight average molecular weight of 100 to 4000 and has two or more hydroxyl groups in one molecule. Polyether polyols, polyester polyols, polycarbonate polyols, and the like can be used. The weight average molecular weight of the aforementioned polymer polyol compound is preferably 500 to 4000, 600 to 3500 is more preferable, and 1,000 to 3000 is more preferable.

Examples of the polyether polyol include aliphatic polyether polyols and aromatic polyether polyols. More specifically, for example, it can be used in triols such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, and hexamethylene glycol, trimethylolpropane, glycerol, and neopentyl alcohol. Polyethers made from the addition of low molecular weight polyols such as alcohols to ethylene oxide, propylene oxide, and tetrahydrofuran. These can be used alone or in combination of two or more.

Examples of the polyester polyol include aliphatic polyester polyols and aromatic polyester polyols. More specifically, alcohols such as the above-mentioned glycols, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and adipic acid, azelaic acid, sebacic acid, and the like can be used. Polyester consisting of polycondensates of dibasic acids. These can be used alone or in combination of two or more.

Polybutadiene polyols such as polybutadiene, butadiene-acrylonitrile copolymer, and polyisoprene having hydroxyl groups at both ends of the molecule; polybutadiene having hydroxyl groups at both ends of the molecule; Polyolefin-based polyols such as hydrides, polyisoprene hydrides, and polyisobutylene.

Examples of the polyamine-based compound that can be used as the chain extender include aliphatic polyamine-based compounds and aromatic polyamine-based compounds. More specifically, examples include ethylenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), diethyltoluenediamine (DETDA), 44'-bis- ( Secondary butyl) diphenylmethane, 2,4-toluenediamine, 2,6-toluenediamine, stub diamine, hexamethylene diamine, isophorone diamine, and the like. Among them, ethylene diamine and the like are suitable. These can be used alone or in combination of two or more.

In addition, the low-molecular-weight polyol and the polyol compound which can be used as a chain elongating agent may also be the low-molecular-weight polyols exemplified in polyether polyols and polyester polyols.

Relative to 100 parts by weight of the above-mentioned polymer polyol compound, the aforementioned chain elongating agent is preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.5 to 7 parts by weight, and more preferably 1 to 5 parts by weight. By using a chain elongating agent, the molecular weight can be sufficiently increased, and durability can be improved.

The isocyanate compound is a polyisocyanate (isocyanate compound) having two or more isocyanate groups, and the same thing as the isocyanate-based forming material can be used. The isocyanate compound can also be used as a urethane prepolymer prepared by reacting the low-molecular polyol exemplified in the polyester polyol and the isocyanate compound exemplified in advance.

In addition, in order to make the isocyanate groups of these polyisocyanates react with hydroxyl groups, dibutyltin dilaurate, tin octoate, 1,4-diazabicyclo (2,2,2) octane, etc. are preferably used as catalysts.

Forming (hardening) a reinforcing film using polyurethane can usually be performed by applying a previously prepared polyurethane liquid material (coating liquid) on a polarizer, or by containing the aforementioned polymer polyol compound The composition with the isocyanate compound is applied to a polarizer and then hardened to form a reactant, and then the reactant is used to form a reinforcing film using polyurethane. The formation of the reinforcing film can usually be performed at about 30 to 100 ° C and preferably at a temperature of 50 to 80 ° C for about 0.5 to 15 minutes.

In addition, an annealing treatment may be performed after the aforementioned reinforcing film is formed (hardened: referred to as initial hardening). The annealing treatment can be carried out especially for the case where the isocyanate-based forming agent and the polyurethane-based forming material are not sufficiently reacted after the initial hardening (the state where the reactive groups remain in the reinforcing film), and the purpose is to promote the reaction. The annealing treatment can be performed arbitrarily in a gas environment in a dry condition or a humidified condition. The annealing treatment temperature is about 30 to 100 ° C, and preferably 50 to 80 ° C, as in the conditions of the initial hardening. The annealing treatment time is not particularly limited.

In addition, the weight average molecular weight of polyurethane is preferably 30,000 to 200,000, more preferably 4 to 150,000, and more preferably 5 to 130,000.

(Measurement of weight average molecular weight) The weight average molecular weight of the polymer polyol compound and polyurethane can be measured by the GPC (gel permeation chromatography) method under the following conditions. Analysis device: Tosoh system, HLC-8120GPC. Column: Tosoh system, G7000HXL + GMHXL + GMHXL. Column size: each 7.8mmφ × 30cm, 90cm in total. Column temperature: 40 ° C. Flow rate: 0.8ml / min. Injection volume: 100 μl. Eluent: tetrahydrofuran. Detector: Differential refractometer. Standard sample: polystyrene.

In addition, as the material for forming the reinforcing film, radical polymerization having a functional group capable of forming a conjugate bond with PVA, such as an isocyanate group and an epoxy group, and a carbon-carbon double bond such as a (meth) acrylfluorene group or a vinyl group, can be used Sex functional compounds. Examples of the compound include 2-isocyanatoethyl acrylate (manufactured by Showa Denko Corporation, product name Karenz AOI), and 1,1- (bispropenyloxymethyl) ethyl isocyanate (manufactured by Showa Denko Corporation, Karenz). BEI) and so on. As the compound, a reaction product of a polymer containing a diisocyanate compound as a constituent and a hydroxy (meth) acrylate-containing compound can be used. Examples of the reactant include a reactant of 2-hydroxyethyl acrylate and a polymer containing 1,6-diisocyanatofluorene hexane as a constituent (Laromer LR9000, manufactured by BASF).

Since the compound has functional groups such as an isocyanate group and an epoxy group, a reinforcing film can be formed by heat curing in the same manner as the isocyanate-based forming agent and the like, and an annealing treatment can be further performed. Moreover, since the said compound has a radical polymerizable functional group, it can be used as an active energy ray hardening type or a thermosetting type forming material related to a radical polymerization hardening type forming material. When used as a radical polymerization hardening type forming material, the said compound can be used together with another radically polymerizable compound.

The reinforcing film may be formed of a forming material containing no hardening component, and may be formed of a forming material containing, for example, the polyvinyl alcohol-based resin as a main component. The polyvinyl alcohol-based resin forming the reinforcing film may be the same as or different from the polyvinyl alcohol-based resin contained in the polarizer as long as it is a "polyvinyl alcohol-based resin".

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol. Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. Examples of the polyvinyl alcohol-based resin include a saponified product of a copolymer of vinyl acetate and a copolymerizable monomer. When the copolymerizable monomer is ethylene, an ethylene-vinyl alcohol copolymer can be obtained. In addition, the aforementioned copolymerizable monomers may include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid, and esters thereof; α-olefins such as ethylene and propylene , (Meth) allylsulfonic acid (sodium), sodium sulfonate (monoalkyl maleate), sodium disulfonate alkyl maleate, N-methylol acrylamide, acrylamine Base salts, N-vinylpyrrolidone, N-vinylpyrrolidone derivatives, and the like. These polyvinyl alcohol-based resins may be used alone or in combination of two or more. From the standpoint of controlling the melting heat of crystallization of the aforementioned reinforced film to 30 mj / mg or more to satisfy the moisture heat resistance or water resistance, it is preferable to use polyvinyl acetate obtained by saponification of polyvinyl acetate.

For example, if the degree of saponification of the polyvinyl alcohol resin is 95% or more, the degree of saponification is from the viewpoint of controlling the heat of crystallization melting of the reinforcing film to 30mj / mg or more to meet the requirements of moisture resistance and water resistance It should be more than 99.0%, more preferably more than 99.7%. The degree of saponification refers to the proportion of units that can be saponified to vinyl alcohol units among the units that can be converted into vinyl alcohol units by saponification, and the residues are vinyl ester units. The degree of saponification can be obtained in accordance with JIS K 6726-1994.

For example, it is possible to use a substance whose average degree of polymerization of the polyvinyl alcohol-based resin is 500 or more. From the viewpoint of controlling the heat of crystalline melting of the reinforcing film to 30 mj / mg or more to satisfy the humidity and heat resistance or water resistance, the average polymerization is The degree should be above 1000, preferably above 1500, more preferably above 2000. The average degree of polymerization of the polyvinyl alcohol resin can be measured in accordance with JIS-K6726.

As the polyvinyl alcohol-based resin, the polyvinyl alcohol or a modified polyvinyl alcohol-based resin having a hydrophilic functional group in a copolymer side chain can be used. Examples of the hydrophilic functional group include acetamidine, carbonyl, and the like. Other modified polyvinyl alcohols, such as acetalization, urethane, etherification, grafting, and phosphate esterification, can be used.

The forming material containing the polyvinyl alcohol-based resin as a main component may contain a curable component (crosslinking agent) and the like. The ratio of the polyvinyl alcohol resin in the reinforcing film or forming material (solid content) is preferably 80% by weight or more, more preferably 90% by weight or more, and more preferably 95% by weight or more. However, from the viewpoint that it is easier to control the heat of crystal melting of the reinforcing film to 30 mj / mg or more, it is preferable that the forming material does not contain a hardening component (crosslinking agent).

As the crosslinking agent, a compound having at least two functional groups reactive with a polyvinyl alcohol-based resin can be used. Examples include ethylene diamine, triethylene diamine, hexamethylene diamine, and other diethylene diamines having an alkylene group and two amine groups; toluene diisocyanate, hydrogenated diisocyanate , Trimethylolpropane diisocyanate toluene adduct, triphenylmethane triisocyanate, methylene bis (4-phenylmethane triisocyanate, isophorone diisocyanate and ketoxime block or phenol of these Isocyanates such as blocks; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol di- or triglycidyl ether, 1,6-hexanediol diepoxy Propyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, diglycidyl amine, etc .; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde; ethylene glycol Dialdehydes such as aldehydes, malonaldehyde, succinaldehyde, glutaraldehyde, malealdialdehyde, and benzaldehyde; hydroxymethyl urea, methylol melamine, alkylated methylol urea, and alkylated methylol Melamine, Ethylguanidine Benzoguanidine Condensates with formaldehyde and other amine-formaldehyde resins; dihydrazine adipate, dihydrazine oxalate, dihydrazine malonate, dihydrazine succinate, dihydrazine glutarate, dihydrazide isophthalate , Dihydrazine sebacic acid, dihydrazine maleate, dihydrazine fumarate, dihydrazine ikonate, and other dicarboxylic acid dihydrazines; ethylene-1,2-dihydrazine, propylene-1,3-dihydrazide Water-soluble dihydrazine such as hydrazine, butene-1,4-dihydrazine. Among these, amine-formaldehyde resin and water-soluble dihydrazine are suitable. The amino-formaldehyde resin is preferably a compound having a methylol group. Among them, methylol melamine, a compound having methylol, is particularly preferred.

From the viewpoint of improving water resistance, the aforementioned hardening component (crosslinking agent) can be used, but the ratio is preferably 20 parts by weight or less, preferably 10 parts by weight or less, and 5 parts by weight based on 100 parts by weight of the polyvinyl alcohol resin. The following is better.

The forming material may be adjusted to a solution in which the polyvinyl alcohol-based resin is dissolved in a solvent. Examples of the solvent include water, dimethylformamide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols, polyhydric alcohols such as alcohols, ethylenediamine, and diethylene glycol. Amines such as ethylenetriamine. These may be used alone or in combination of two or more kinds. Among these, an aqueous solution using water as a solvent is preferably used. The concentration of the polyvinyl alcohol-based resin in the forming material (for example, an aqueous solution) is not particularly limited, and considering coating properties and standing stability, etc., it is 0.1 to 15% by weight, and preferably 0.5 to 10% by weight.

Examples of additives that can be incorporated into the aforementioned forming material (such as an aqueous solution) include plasticizers and surfactants. Examples of the plasticizer include polyols such as ethylene glycol and glycerin. The surfactant may be, for example, a nonionic surfactant.

The reinforcing film may be formed by applying the forming material to a polarizer and drying it. The coating operation is not particularly limited, and an arbitrary and appropriate method can be adopted. For example, various methods such as a roll coating method, a spin coating method, a wire rod coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, a doctor blade coating method (notched wheel coating method, etc.) can be used. means.

<Surface treatment layer> A surface treatment layer may be provided on one side or both sides of the flexible polarizing film of the present invention. Examples of the surface treatment layer include a hard coat layer, an anti-glare treatment layer, an anti-reflection layer, and an anti-adhesion layer. The aforementioned surface treatment layer is preferably a hard coating layer. As a material for forming the hard coat layer, for example, a thermoplastic resin or a material hardened by heat or radiation can be used. Examples of the material include radiation curable resins such as thermosetting resins, ultraviolet curable resins, and electron beam curable resins. Among these, an ultraviolet-curable resin is more suitable, and the ultraviolet-curable resin can efficiently form a cured resin layer with a simple processing operation by a curing process using ultraviolet irradiation. Examples of these hardening resins include polyester, acrylic, urethane, ammonium, silicone, epoxy, and melamine resins, and monomers and oligomers including these. , Polymer, etc.

The surface treatment layer may be provided with an anti-glare treatment layer or an anti-reflection layer for the purpose of improving the visibility. An anti-glare treatment layer or an anti-reflection layer may be provided on the hard coat layer. The constituent material of the anti-glare treatment layer is not particularly limited, and examples thereof include radiation-curable resins, thermosetting resins, and thermoplastic resins. As the anti-reflection layer, titanium oxide, zirconia, silicon oxide, magnesium fluoride, or the like can be used. The anti-reflection layer may be provided in a plurality of layers. Other examples of the surface treatment layer include an anti-adhesion layer.

The thickness of the aforementioned surface treatment layer can be appropriately set according to the type of the surface treatment layer, and is generally preferably 0.1 to 100 μm. For example, the thickness of the hard coating layer should be 0.5 to 20 μm.

<Adhesive layer> An adhesive layer may be provided on one or both sides of the flexible polarizing film of the present invention. An appropriate adhesive can be used when forming the adhesive layer, and there is no particular limitation on the type. Examples of the adhesive include a rubber adhesive, an acrylic adhesive, a silicone adhesive, a urethane adhesive, a vinyl alkyl ether adhesive, a polyvinyl alcohol adhesive, and polyvinylpyrrolidone. Adhesive, Polyacrylamide Adhesive, Cellulose Adhesive, etc.

Among these adhesives, those which are excellent in optical transparency, exhibit moderate adhesion characteristics such as wettability, cohesiveness, and adhesiveness, and are excellent in weather resistance and heat resistance are also suitable. As the adhesive exhibiting such characteristics, an acrylic adhesive is suitably used.

The method for forming an adhesive layer can be produced, for example, by applying the aforementioned adhesive to a separator subjected to a peeling treatment, etc., drying and removing the polymerization solvent, etc. to form an adhesive layer, and then transferring it to flexible polarized light. A method of coating a film; or a method of coating the flexible polarizing film with the aforementioned adhesive and drying and removing a polymerization solvent or the like to form an adhesive layer on the polarizer. In addition, the application of the adhesive may appropriately add one or more solvents other than the polymerization solvent.

The thickness of the adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm. It is preferably 2 to 50 μm, more preferably 2 to 40 μm, and more preferably 5 to 35 μm.

When the aforementioned adhesive layer is exposed, the adhesive layer may be protected by a peeled sheet (separator) before it is used for actual use.

<Surface Protection Film> A surface protection film may be provided on the flexible polarizing film of the present invention. The surface protection film usually has a base film and an adhesive layer, and the flexible polarizing film is protected by the adhesive layer.

From the viewpoints of inspection and management, the base film of the surface protection film can be selected to have an isotropic or nearly isotropic film material. Examples of the film material include polyester resins such as polyethylene terephthalate films, cellulose resins, acetate resins, polyether fluorene resins, polycarbonate resins, and polyamine resins. , Polyimide resin, polyolefin resin, acrylic resin and other transparent polymers. Among these, a polyester resin is preferable. The base film can be used as a laminate of one or more film materials, or an extension of the aforementioned film can be used. The thickness of the base film is generally 500 μm or less, and preferably about 10 to 200 μm.

The adhesive that forms the adhesive layer of the surface protection film can be appropriately selected and used. (Meth) acrylic polymer, polysiloxane polymer, polyester, polyurethane, polyamide, polyether, fluorine A polymer such as rubber or the like is used as an adhesive for the base polymer. From the viewpoints of transparency, weather resistance, and heat resistance, an acrylic adhesive using an acrylic polymer as a base polymer is preferable. The thickness (dry film thickness) of the adhesive layer can be determined according to the required adhesive force. It is usually about 1 to 100 μm, and preferably 5 to 50 μm.

For the surface protection film, a peeling treatment layer may be provided through a low-adhesion material such as a polysiloxane treatment, a long-chain alkyl treatment, or a fluorine treatment on the opposite side of the surface of the base film on which the adhesive layer is provided.

<Other optical layers> The flexible polarizing film of the present invention can be used as a substitute for a polarizer or a polarizing film (a transparent protective film is provided on the polarizer) to expand various uses that could not be applied to conventional polarizers or polarizing films. For example, it can also be used as an optical film laminated with another optical layer. The other optical layers are not particularly limited. For example, when the flexible polarizing film of the present invention is used as a substitute for a polarizer, a protective film (also including a retardation film, a brightness enhancement film, and a diffusion film) for protecting the polarizer can be used. Etc.); when used as an alternative to polarizing films, one or more than two reflective or semi-transparent plates, retardation films (including 1/2 or 1/4 wavelength plates), viewing angle compensation films, etc. can be used It can be used to form an optical layer such as an image display device such as a liquid crystal display device or an organic EL display device.

<Intermediate layer> The optical layer and the flexible polarizing film may be laminated via an intermediary layer such as an adhesive layer, an adhesive layer, and a primer layer. At this time, it is hoped that the two can be laminated without an air gap through the interposer.

The flexible polarizing film of the present invention or an optical film using the same can be favorably applied to the formation of various image display devices such as a liquid crystal display device and an organic EL display device. The formation of a liquid crystal display device can proceed as before. That is, the liquid crystal display device can generally be formed by suitably assembling and arranging a driving circuit and the like with the liquid crystal element and the flexible polarizing film of the present invention or the optical film using the component and the lighting system on demand, etc., except for using the flexible of the present invention. The polarizing film is not limited except for one point, and it must be in accordance with the convention. As the liquid crystal element, any type such as an IPS type and a VA type can be used, and an IPS type is particularly preferable. Examples

The present invention will be illustrated by the following examples, but the present invention is not limited to the examples shown below. In addition, parts and% in each case are a basis of weight. All room temperature standing conditions not specified below are 23 ° C and 65% RH.

＜ Production of Polarizer A0 ＞ Corona treatment was performed on one side of an amorphous isophthalic acid copolymerized polyethylene terephthalate ((IPA copolymerized PET) film (thickness: 100 μm)) having a water absorption of 0.75% and a Tg of 75 ° C. After the treatment, the corona treated surface was coated at 25 ° C with a ratio of 9: 1 containing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mole%) and acetamidine modified PVA (degree of polymerization) 1200, an aqueous solution of acetamidine modification degree of 4.6%, saponification degree of 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. under the trade name "GOHSEFIMERTM Z200") and dried to form a PVA-based resin layer with a thickness of 11 μm, The laminated body was made. The obtained laminated body was uniaxially extended 2.0 times in the longitudinal (long-side direction) free end between rollers with different turnover ratios in an oven at 120 ° C (air-assisted extension treatment). Next, the laminated body was immersed in 30 seconds in an insoluble bath (aqueous boric acid solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 30 ° C (insolubilization treatment). Then, immerse it in a dyeing bath at a liquid temperature of 30 ° C. At the same time, the iodine concentration and the immersion time are adjusted so that the polarizing plate has a predetermined transmittance. In this example, it is immersed in an aqueous iodine solution for 60 seconds, and the aqueous iodine solution is obtained by mixing 0.2 parts by weight of iodine and 1.0 part by weight of potassium iodide (dyeing treatment) with 100 parts by weight of water. A crosslinking bath (aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with 100 parts by weight of water) at a temperature of 30 ° C (crosslinking treatment). Thereafter, the laminate was immersed in the liquid temperature 70 ° C boric acid aqueous solution (aqueous solution obtained by mixing 100 parts by weight of water with 4 parts by weight of boric acid and 5 parts by weight of potassium iodide), at the same time between the rollers with different turnover rates in the longitudinal direction (long side direction) and Uniaxial stretching (stretching in water) was performed so that the stretching ratio became 5.5 times. Then, the laminate was immersed in a washing bath at a liquid temperature of 30 ° C (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (washing (Net treatment). An optical film laminate containing a polarizer having a thickness of 5 μm was obtained in the manner described above.

<Production of Polarizers A1 to A2> The polarizers A1 to A2 were produced in the same manner as the production of the polarizer A0 except that the production conditions of the above-mentioned polarizer A0 were changed as shown in Table 1. The thickness, optical characteristics (transmittance, polarization degree), and boric acid concentration of the polarizers A0 to A2 are shown in Table 1.

[Table 1]

<Production of Polarizer B1 (Polarizer with Thickness of 12 μm)> A polyvinyl alcohol film having an average polymerization degree of 2400, a saponification degree of 99.9 mol%, and a thickness of 30 μm was immersed in warm water at 30 ° C. for 60 seconds to swell. Next, it was immersed in a 0.3% aqueous solution of iodine / potassium iodide (weight ratio = 0.5 / 8), stretched to 3.5 times, and dyed the film. Then, stretching was performed in a boric acid ester aqueous solution at 65 ° C. so that the total stretching ratio became 6 times. After stretching, it was dried in an oven at 40 ° C for 3 minutes to obtain a polarizer B1. The thickness of the obtained polarizer B1 was 12 μm. The optical characteristics of the obtained polarizer B1 were 42.8% transmittance and 99.99% polarization.

<Production of Polarizer B2 (Polarizer with a Thickness of 23 μm)> A polyvinyl alcohol film having an average degree of polymerization of 2400, a degree of saponification of 99.9 mol%, and a thickness of 75 μm was immersed in warm water at 30 ° C. for 60 seconds to swell. Next, it was immersed in a 0.3% aqueous solution of iodine / potassium iodide (weight ratio = 0.5 / 8), stretched to 3.5 times, and dyed the film. Then, stretching was performed in a boric acid ester aqueous solution at 65 ° C. so that the total stretching ratio became 6 times. After stretching, it was dried in an oven at 40 ° C for 3 minutes to obtain a polarizer B2. The thickness of the obtained polarizer B2 was 23 μm. The optical characteristics of the obtained polarizer B2 were 42.8% transmittance and 99.99% polarization.

<Reinforcing film forming material> (1) 50 parts of a polyurethane-based material in an urethane prepolymer (manufactured by Tosoh Corporation, Coronate L) composed of toluene diisocyanate and trimethylolpropane 50 parts of polycarbonate polyol (Sumika Bayer Urethane Co., Ltd., Desmophen C3100XP), dioctyl dilaurate (Tokyo Fine Chemical CO., LTD., EMBILIZER OL-1) 0.1 were added. A coating liquid adjusted to a solid content concentration of 35% was obtained using methyl isobutyl ketone as a solvent.

(2) 50 parts of UV hardening material is urethane acrylate oligomer (manufactured by Nippon Synthetic Chemical Co., Ltd., UV light 1700TL), and 2-hydroxyethyl acrylate and 1,6-diisocyanatohexane are added as 50 parts of a polymer reactant (manufactured by BASF, product name Laromer LR9000), 3 parts of a photoinitiator (manufactured by BASF, IRGACURE907), and adjusted to a solid content by using methyl isobutyl ketone as a solvent 35% coating solution.

(3) Water-based resin latex material An acrylic latex (manufactured by TAISEI FINE CHEMICAL CO, .LTD., Trade name: SE-2915E) was added with pure water as a solvent to obtain a coating solution adjusted to a solid content concentration of 30%.

<Protective film (acrylic polymer) and adhesive> Corona treatment is applied to the easy-to-treat surface of a (meth) acrylic resin film having a thickness of 20 μm and having a lactone ring structure, and is used.

The adhesive to which the protective film (acrylic polymer) is applied is a mixture of 40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acrylmorpholine (ACMO), and a photoinitiator "IRGACURE 819". (Manufactured by BASF) 3 parts by weight were mixed to prepare an ultraviolet curing adhesive.

Example 1 (Production of a Flexible Polarizing Film) A polarizer (first surface) of the polarizer A0 (the optical film laminate including a polarizer with a thickness of 5 μm) obtained above was cured with a wire rod coater to a thickness of 5 μm. After the polyurethane-based material (1) of the above-mentioned reinforcing film is applied in the manner described above, it is initially hardened at 60 ° C for 10 minutes, and then annealed at 60 ° C for 12 hours to form a first 1 Reinforcing membrane. Next, a surface protective film (manufactured by Nitto Denko, RP301) was bonded to the first reinforcing film, and then the amorphous PET substrate of the optical film laminate was peeled. Then, the polarizer (the second surface of the peeling surface) was coated with a polyurethane-based material (1) of the above-mentioned reinforcing film so as to have a thickness of 5 μm after curing using a wire bar coater, and then allowed to stand at 60 ° C., It was initially hardened at 10 minutes, and then annealed at 60 ° C for 12 hours to form a second reinforcing film. Thereafter, the surface protective film attached to the first reinforcing film was removed to obtain a flexible polarizing film having a reinforcing film on both sides of the polarizer.

Examples 2 to 4 Flexible polarizing films having reinforcing films on both sides of the polarizer were produced in the same manner as in Example 1 except that the type of the polarizer and the thickness of the reinforcing film of Example 1 were changed as shown in Table 2.

Example 5 (Production of Flexible Polarizing Film) The polarizer (first side) of the polarizer A0 (optical film laminate containing a polarizer with a thickness of 5 μm) obtained above was cured with a wire rod coater to a thickness of 5 μm. After the UV curing material (2) of the above-mentioned reinforcing film was applied in this manner, it was heated at 60 ° C for 1 minute. The heated coating film was irradiated with ultraviolet light with a cumulative light amount of 300 mJ / cm ² with a high-pressure mercury lamp to form a first reinforcing film. Next, a surface protective film (manufactured by Nitto Denko, RP301) was bonded to the first reinforcing film, and then the amorphous PET substrate of the optical film laminate was peeled. Then, the polarizer (the second surface of the peeling surface) was coated with a UV-curable material (2) of the above-mentioned reinforcing film with a wire rod coater so as to have a thickness of 5 μm after curing, and then heated at 60 ° C. for 1 minute. The heated coating film was irradiated with ultraviolet light having a cumulative light amount of 300 mJ / cm ² with a high-pressure mercury lamp to form a second reinforcing film. Thereafter, the surface protective film attached to the first reinforcing film was removed to obtain a flexible polarizing film having a reinforcing film on both sides of the polarizer.

Example 6 (Production of Flexible Polarizing Film) The polarizer (first side) of the polarizer A0 (optical film laminate containing a polarizer with a thickness of 5 μm) obtained above was cured with a wire rod coater to a thickness of 5 μm. After the water-based resin latex material (3) of the above-mentioned reinforcing film was applied in this manner, it was cured at 80 ° C. for 5 minutes to form a first reinforcing film. Next, a surface protective film (manufactured by Nitto Denko, RP301) was bonded to the first reinforcing film, and then the amorphous PET substrate of the optical film laminate was peeled. Then, the polarizer (the second surface of the peeling surface) was coated with a water-based resin latex material (3) of the above-mentioned reinforcing film with a wire rod coater so as to have a thickness of 5 μm after curing, and then allowed to stand at 80 ° C for 5 minutes. It hardens under the conditions to form a second reinforcing film. Thereafter, the surface protective film attached to the first reinforcing film was removed to obtain a flexible polarizing film having a reinforcing film on both sides of the polarizer.

Example 7 A flexible polarizing film having a second reinforcing film only on one side of a polarizer was produced in the same manner as in Example 1 except that the first reinforcing film was not provided in Example 1.

Example 8 A flexible polarizing film having a first reinforcing film only on one side of a polarizer was produced in the same manner as in Example 1 except that a second reinforcing film was not provided as in Example 1.

Comparative Examples 1 to 3 A polarizing film with a reinforcing film provided with a reinforcing film on both sides of the polarizer was produced in the same manner as in Example 1 except that the type of the polarizer and the thickness of the reinforcing film of Example 1 were changed to those shown in Table 2. .

Comparative Example 4 (Production of a single-sided protective polarizing film) A polarizer (first surface) of the polarizer A0 (optical film laminate including a polarizer with a thickness of 5 μm) obtained above was obtained by curing the adhesive layer with a thickness of 1 μm After applying the above-mentioned UV-curable adhesive, and bonding the above-mentioned protective film (acrylic polymer), ultraviolet rays are irradiated as active energy rays to harden the adhesive. The ultraviolet irradiation system uses a gallium-encapsulated metal halide lamp, an irradiation device: Fusion UV Systems, Inc. Light HAMMER10, a valve: a V-type valve, a peak illuminance: 1600 mW / cm ² , and a cumulative exposure of 1000 / mJ / cm ² (wavelength 380 ~ 440 nm), and the ultraviolet irradiance was measured using a Sola-Check system manufactured by Solatell. Next, the amorphous PET substrate of the optical film laminate was peeled to obtain a single-sided protective polarizing film.

Samples were prepared for the flexible polarizing film obtained in the above example and the polarizing film with a reinforcing film obtained in the comparative example, and the single-sided protective polarizing film for the following evaluations. The results are shown in Table 2. In addition, Comparative Examples 5 to 7 were evaluated for the individual elements of the polarizers A0, A1, and B1. The thinner polarizers A0 and A1 are relatively weak, and the evaluation of the monomers cannot be measured except for the rigidity. The evaluation was performed under the conditions of 23 ° C and 65% RH.

<Unit Transmittance T and Polarization P of Polarizer> Using the spectrotransmittance measuring device (Dot-3c of Murakami Color Technology Research Institute) with an integrating sphere, the unit transmittance T and polarization P of the obtained polarizing film were measured. . In addition, the degree of polarization P is the transmittance (parallel transmittance: Tp) when two identical polarizing films are overlapped in parallel with the transmission axes of the two and the transmittance (orthogonal transmission) Rate: Tc) is calculated by applying the following formula. Polarization P (%) = {(Tp-Tc) / (Tp + Tc)} ^1/2 × 100 The transmittances are such that the full polarized light obtained through Glan-Taylor 稜鏡 is 100% and the Y value obtained by correcting the optical performance of the 2-degree field of view (C light source) of JIS Z8701.

<Measurement of Compression Elastic Coefficient> The measurement of the compression elastic coefficient was performed using TI900 TriboIndenter (manufactured by Hysitron). The obtained polarizing member (polarizing film) with a reinforcing film was cut into a size of 10 mm × 10 mm and fixed on a support provided by TriboIndenter, and then the coefficient of compressive elasticity was measured by the nanoindentation method. At that time, the use indenter is adjusted to a position near the center of the transparent layer. The measurement conditions are listed below. Indenter: Berkovich (triangular cone type) Measurement method: Single indentation measurement Measurement temperature: 23 ° C Indentation depth setting: 100nm

<Bend retention test> A rectangular object 1 (sample) of 200 mm (absorption axis direction) × 300 mm (transmission axis direction) was set on a water table 31. Next, the rectangular object 1 was folded in three in the transmission axis direction (long axis direction), and then a 100 g weight 32 was loaded so as to apply a load to the entire uppermost surface and left to stand for 5 minutes. The bent state is shown in FIG. 2. The aforementioned weight 32 is then removed. Further, the same operation was performed on a rectangular object (sample) of 200 mm (transmission axis direction) × 300 mm (absorption axis direction) (however, the sample was folded in three directions in the absorption axis direction (long axis direction)). After the bending retention test, visually confirm whether the sample is maintained in a three-folded state. After confirming that the sample is maintained in a three-folded shape, return the sample to its original shape (flat surface), and evaluate visually based on the following criteria. The evaluation was performed three times for samples having a long side in the transmission axis direction and a long side in the absorption axis direction. ○: All samples maintained a tri-fold shape without cracks, and maintained their original shape (retainability). ×: Any of the samples failed to maintain the tri-fold shape. Or, although it has a three-folded shape, cracks are generated when it is loaded (no retention).

<Torsion test> No-tension Torsion Test for Planar Object (No-tension Torsion Test for Planar Object, product name: Body TCDM111LH and fixture: No-load torsion test fixture for surface objects) made by YUASA SYSTEM Co., Ltd. get on. The two short sides of a rectangular object 1 (sample) of 100 mm (absorption axis direction) x 150 mm (transmission axis direction) were clamped and fixed with the torsion fixtures 11 and 12 of the testing machine, and one of the short sides was maintained by the fixture 12 In a fixed state, the other short-side clamp 11 is twisted under the following conditions. The twisted state is shown in FIG. 3. Torsional speed: 10 rpm Torsional angle: 45 degrees Number of twists: 100 times The state of the sample after the twist test was visually evaluated according to the following criteria. ○: No cracks and light leakage occurred, and no residual creases were left. △: No cracks or light leakage occurred, but there were residual creases. ×: Cracks and light leakage occurred, and creases remained.

<U-shaped Flexure Test> A non-loaded U-shaped flexure tester (product name: body DLDM111LH and fixture: unloaded U-shaped flexure test fixture for surface objects) made by YUASA SYSTEM Co., Ltd. was used. Using double-sided tape (not shown), fix both ends x and y (50mm) of the rectangular object 1 (sample) of 50mm (absorption axis direction) x 100mm (transmission axis direction) to the support part 21 of the tester, After 22, expand and contract in a U-shape such that the single-sided side (first surface) of the rectangular object 1 faces inward under the following conditions, and bend the rectangular object (bending of the first surface side in the transmission axis direction) . One process state of U-shaped stretching is shown in FIG. 4. In the U-shaped telescopic system, the bend R (bend radius) is set to 0, and the rectangular object 1 (sample) is bent from a flat state to contact in a folded state. The aforementioned bending system causes the two end portions x and y to contact the two end portions x and y by the operation of the support portion, and the remaining portion of the rectangular object 1 (sample) is simultaneously provided with the plate portions 23 and 24 separately provided from the outer sides. Hold and touch without load. In addition, the bending of the expansion and contraction may also expand and contract the other surface side (second surface) of the rectangular object in a U-shape such that it faces inward in the same manner as above (bending of the second surface side in the transmission axis direction). ). In addition, the above-mentioned telescopic bending also has a rectangular shape (sample) of 50 mm (transmission axis direction) × 100 mm (absorption axis direction), and the first and second surfaces face the inside in a U shape in the same manner as described above. Performs expansion and contraction (bending of the first surface side and the second surface side in the absorption axis direction). Stretching speed: 30 rpm Bending R: 0 Number of stretching: 100 times According to the following criteria, visually evaluate the state of the sample in the U-shaped stretching test. 〇: In the bending of the first surface side and the second surface side in the transmission axis direction and the bending of the first surface side and the second surface side in the absorption axis direction, no cracks or light leakage occurred in all the bends. And no residual creases. ×: In the bending of the first surface side and the second surface side in the transmission axis direction, and the bending of the first surface side and the second surface side in the absorption axis direction, cracks or light leakage occurred in any of the bends. Or confirm creases.

Criteria for judging cracks, creases, and light leakage in the above-mentioned bending retention test, torsion test, and U-shaped stretch test are as follows. "Crack" means that a crack or crack has penetrated through the sample (a flexible polarizing film, a polarizing film with a reinforcing film, or an entire layer or a partial layer constituting a single-sided protective polarizing film). "Crease" means that the specimen (flexible polarizing film, polarizing film with reinforced film, or the entire layer or part of a layer that forms a single-sided protective polarizing film) has a removal load due to bending or local load. Recognizable traces remain afterwards. "Light leakage" indicates that a crack or crack occurred in the polarizer itself. The confirmation of light leakage is that the sample after the test (flexible polarizing film, polarizing film with reinforced film, or the entire layer constituting a single-sided protective polarizing film) and other ordinary polarizing films are bonded to the glass in a crossed Nicols state It is performed on both sides and transmits light such as backlight.

<Rigidity and softness test> No.476 cantilever type softness tester manufactured by Yasuda Seiki Co., Ltd. was used. In addition, in this test, the samples used in the test are moderately de-energized to eliminate the influence of static electricity. A rectangular object 1 (sample) of 50 mm (in the direction of the absorption axis) × 150 mm (in the direction of the transmission axis) is placed on the top surface of the SUS plate 41 in an anastomotic manner. The sample is the same size), and has a 45 ° bevel at one end of the long side, and the cross section is a smooth trapezoid (see Figure 5). The sample is arranged obliquely in the direction of the transmission axis. The sample was smoothly slid toward the inclined side at a pushing speed of 10 mm / sec (1). Where the front end of the sample first touches the slope, stop the sample movement (2). The distance L (mm) of the sample movement was measured on the top plane. The same operation as described above was performed on a rectangular object (sample of a flexible polarizing film) of 50 mm (transmission axis direction) × 150 mm (absorption axis direction) (however, the sample was set obliquely to face the absorption axis direction). Rigidity (mm) is measured for the longest side of the transmission axis direction and the longest side of the absorption axis direction. The shortest straight line distance is measured respectively with the first surface as the upper side and the second surface as the upper side. L (mm) 3 times (total 12 samples), and take the arithmetic mean of these. In addition, when one or more of the 12 samples were measured and the sample could not be measured due to deformation or curl of the sample, it was determined that the sample could not be measured.

<Tensile test> A multi-purpose test piece cutting machine (dumbbell cutter) was cut into a predetermined shape of 10 mm (absorption axis direction) x 150 mm (transmission axis direction) to prepare a sample (a sample of a flexible polarizing film). ). For the aforementioned sample, an autostereograph AG-IS manufactured by Shimadzu Corporation was used, and a tensile test was performed at a tensile speed: 50 mm / min. The clamps 51 and 52 were used to fix both sides of the specimen in the transmission axis direction (the distance 53 between the initial clamps was 50 mm), and one of the clamps 52 was stretched (see FIG. 6). The place where the specimen started to break or plastically deformed was evaluated as "tensile strength". Tensile strength is the arithmetic average after three measurements.

[Table 2]

1‧‧‧flexible polarizing film
11, 12‧‧‧ fixture
21, 22‧‧‧ Support Department
23, 24‧‧‧ Board
31‧‧‧water platform
32‧‧‧ Heavy
41‧‧‧SUS pallet
51, 52‧‧‧ Clamp
53‧‧‧Distance between initial clamps
a‧‧‧Transparent protective film
b1‧‧‧The first reinforcing film
b2‧‧‧The second reinforcement film
L‧‧‧ shortest straight distance
x, y‧‧‧ end

1 (A)-(B) are examples of schematic cross-sectional views of a flexible polarizing film of the present invention. FIG. 2 is a schematic view showing a folded state in a bending holding test. FIG. 3 is a schematic diagram showing a twisted state during a torsion test. FIG. 4 is a schematic diagram showing a U-shape state during a U-shape stretch test. FIG. 5 is a schematic diagram showing rigidity in a rigidity test. Fig. 6 is a schematic diagram showing a tensile test.

1‧‧‧flexible polarizing film

a‧‧‧Transparent protective film

b1‧‧‧The first reinforcing film

b2‧‧‧The second reinforcement film

Claims (17)

A flexible polarizing film, characterized in that it has a polyvinyl alcohol-based polarizer with a thickness of 10 μm or less, and the polyvinyl alcohol-based polarizer is oriented in one direction with respect to the polyvinyl alcohol-based resin, and the polyvinyl alcohol-based resin is adsorbed and aligned with It is made of iodine or dichroic pigment, and when the flexible polarizing film is subjected to a bending retention test, the flexible polarizing film is kept bent in the alignment direction of the polyvinyl alcohol-based resin alignment and the direction orthogonal to the alignment direction, and then left to stand. Bend shape can be maintained in all directions without cracks. For example, when the flexible polarizing film of claim 1 is subjected to a torsion test, it does not have cracks, creases, and light leakage after being twisted in the direction in which the polyvinyl alcohol-based resin is aligned. For example, when the flexible polarizing film of claim 1 or 2 is subjected to a U-shaped stretching test, the flexible polarizing film is repeatedly stretched in a U-shape in the direction of the orientation of the polyvinyl alcohol-based resin alignment and the direction orthogonal to the foregoing alignment direction, and then in No cracks, creases or light leakage in all directions. The flexible polarizing film according to any one of claims 1 to 3, when performing a rigidity test on the alignment direction of the polyvinyl alcohol-based resin alignment and the direction orthogonal to the alignment direction, the stiffness (mm) It is 60mm or less. The flexible polarizing film according to any one of claims 1 to 4, in a tensile test, the tensile strength in a direction orthogonal to the alignment direction of the polyvinyl alcohol-based resin alignment is 5N / 10 mm or more. The flexible polarizing film according to any one of claims 1 to 5, wherein the aforementioned polyvinyl alcohol-based polarizer is configured so that the optical characteristics represented by the single transmittance T and the polarization degree P satisfy the condition of the following formula: P> -(10 ^0.929T-42.4 -1) × 100 (only T <42.3), or P ≧ 99.9 (only T ≧ 42.3). The flexible polarizing film according to any one of claims 1 to 6, which has a reinforcing film adhered to the polyvinyl alcohol-based polarizer on at least one side of the polyvinyl alcohol-based polarizer. The flexible polarizing film according to claim 7, wherein the thickness of the aforementioned reinforcing film is 15 μm or less. For example, the flexible polarizing film of claim 8 has a first reinforcing film having a thickness of 15 μm or less on the first side of the polyvinyl alcohol-based polarizer, and a second reinforcing film having a thickness of 15 μm or less on the second side of the other side. Reinforcing membrane. For example, the flexible polarizing film of claim 9, wherein the thickness difference between the first reinforcing film and the second reinforcing film is 10 μm or less. The flexible polarizing film according to any one of claims 7 to 10, wherein the ratio of the thickness of the reinforcing film to the thickness of the aforementioned polyvinyl alcohol-based polarizer is 0.4 or more. The flexible polarizing film according to any one of claims 7 to 11, wherein the compression elastic coefficient of the aforementioned reinforcing film at 23 ° C is 1 MPa or more. The flexible polarizing film according to any one of claims 7 to 12, wherein the aforementioned reinforcing film is not substantially aligned. The flexible polarizing film according to any one of claims 7 to 13, wherein the aforementioned reinforcing film is a resin film. The flexible polarizing film according to claim 14, wherein the resin film is a product of a thermosetting resin or an active energy ray curing resin. A method for manufacturing a flexible polarizing film is to manufacture the flexible polarizing film as claimed in claim 14 or 15, and the manufacturing method is characterized by comprising: step (1), preparing a polyvinyl alcohol-based polarizer having a thickness of 10 μm or less, the The polyvinyl alcohol-based polarizer is aligned with the polyvinyl alcohol-based resin in one direction and the polyvinyl alcohol-based resin is adsorbed and aligned with iodine or a dichroic pigment; and step (2), the polyvinyl alcohol-based polarizer is After a liquid material containing a resin component or a curable component constituting a resin film is applied on at least one side, the liquid material is cured or hardened to form a reinforcing film. An image display device having a flexible polarizing film according to any one of claims 1 to 15.