KR102262499B1 - Flexible polarizing film, manufacturing method thereof, and image display device - Google Patents

Abstract

The present invention has a polyvinyl alcohol-based polarizer with a thickness of 10 μm or less, wherein the polyvinyl alcohol-based resin is oriented in one direction, and iodine or a dichroic dye is adsorbed and oriented to the polyvinyl alcohol-based resin, and the polyvinyl alcohol-based polarizer After conducting a U-shaped stretch test in which the vinyl alcohol-based resin repeats stretching and contracting in a U-shape in the direction orthogonal to the orientation direction and the orientation direction, there is no crack, fold, or light leakage in any direction It relates to a flexible polarizing film comprising Although the flexible polarizing film of the present invention uses a polyvinyl alcohol-based polarizer, it has a high degree of flexibility (flexibility).

Description

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

The present invention relates to a flexible polarizing film and a method for manufacturing the same. The flexible polarizing film may form an image display device such as a liquid crystal display device (LCD) or an organic EL display device, either alone or as an optical film in which the flexible polarizing film is laminated.

It is indispensable to a liquid crystal display device to arrange|position a polarizer on both sides of the glass substrate which forms the liquid crystal panel surface from the image formation method. As the polarizer, a polyvinyl alcohol-based polarizer is generally used in which a polyvinyl alcohol-based resin is oriented in one direction and an iodine or a dichroic dye is adsorbed and oriented to the polyvinyl alcohol-based resin. . However, polyvinyl alcohol-based polarizers have a problem that they are brittle and easily torn as a single unit. In particular, the polyvinyl alcohol-based polarizer is easily torn parallel to the direction in which the polyvinyl alcohol-based resin is oriented (absorption axis direction), and is easily torn when, for example, an external force to shrink in the absorption axis direction is applied.

Therefore, it is common that polyvinyl alcohol-type polarizer is used as the polarizing film which bonded the transparent protective film together on the single side|surface or both surfaces.

As other polarizers, grid polarizers other than polyvinyl alcohol-based polarizers are known (Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 2005-316495 Japanese Patent Laid-Open No. 2007-232792

However, a general polarizing film using a polyvinyl alcohol-based polarizer has rigidity (elasticity) and lacks flexibility (flexibility) because a transparent protective film is bonded together. Therefore, when twisting is applied to the polarizing film, its use is restricted due to cracks occurring in the entire film, fold marks (fold traces), or light leakage occurring in the polarizer. On the other hand, the grid polarizer has flexibility but lacks versatility.

An object of the present invention is to provide a flexible polarizing film having a high degree of flexibility in spite of using a polyvinyl alcohol-based polarizer and a method for manufacturing 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 earnest examination, this inventor discovered that the said subject could be solved with the following flexible polarizing film etc., and led to this invention.

That is, the present invention has a polyvinyl alcohol-based polarizer having a thickness of 10 μm or less, wherein the polyvinyl alcohol-based resin is oriented in one direction, and iodine or a dichroic dye is adsorbed and oriented to the polyvinyl alcohol-based resin, and After conducting a U-shaped stretch test in which the polyvinyl alcohol-based resin repeats stretching and contracting in a U-shape in the direction orthogonal to the orientation direction and the orientation direction, there is no crack, crease, or light leakage in any direction. It relates to a flexible polarizing film, characterized in that.

In the flexible polarizing film, it is preferable that there are no cracks, folds, and light leakage after performing a twist (salting) test in the direction in which the polyvinyl alcohol-based resin is oriented.

In the flexible polarizing film, after performing a bending maintenance test in which the polyvinyl alcohol-based resin is bent and held in a direction orthogonal to the orientation direction and the orientation direction, the bent shape is maintained in any direction At the same time, it is desirable that no cracks occur.

In the flexible polarizing film, in the orientation direction in which the polyvinyl alcohol-based resin is oriented, and in the stiffness test in a direction orthogonal to the orientation direction, it is preferable that the stiffness (mm) is 60 mm or less. .

In the flexible polarizing film, it is preferable that the tensile strength in a direction orthogonal to the orientation direction in which the polyvinyl alcohol-based resin is oriented in a tensile test is 5 N/10 mm or more.

In the flexible polarizing film, the polyvinyl alcohol-based polarizer has an optical characteristic expressed by a single transmittance (T) and a degree of polarization (P) by the following formula

P>-(10 ^0.929T-42.4 -1)×100 (however, T<42.3), or

It is preferable that it is configured to satisfy the condition of P≧99.9 (however, T≧42.3).

In the flexible polarizing film, it is preferable to have a reinforcing film in close contact with the polyvinyl alcohol-based polarizer on both surfaces of the polyvinyl alcohol-based polarizer. It is preferable that the thickness of the said reinforcing film on at least one side is 15 micrometers or less.

In the flexible polarizing film, it is preferable that the polyvinyl alcohol-based polarizer has a first reinforcing film having a thickness of 15 µm or less on a first side thereof and a second reinforcing film having a thickness of 15 µm or less on the second side of the other side of the polyvinyl alcohol-based polarizer. It is preferable that a thickness difference between the first reinforcing film and the second reinforcing film is 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 reinforcing film preferably has a compressive elastic modulus at 23° C. of 1 MPa or more.

In the flexible polarizing film, the reinforcing film may be substantially not oriented.

In the flexible polarizing film, a resin film may be used as the reinforcing film. It is preferable that the said resin film is a formation of a thermosetting resin or an active energy ray-curable resin.

In addition, the present invention provides a method for manufacturing the flexible polarizing film,

A step (1) of preparing a polyvinyl alcohol-based polarizer having a thickness of 10 μm or less, in which the polyvinyl alcohol-based resin is oriented in one direction and iodine or a dichroic dye is adsorbed and oriented to the polyvinyl alcohol-based resin;

Step (2) of forming a reinforcing film by coating a liquid material containing a resin component or a curable component capable of constituting a resin film on both surfaces of the polyvinyl alcohol-based polarizer, and then solidifying or curing the liquid material It relates to a method of manufacturing a flexible polarizing film, comprising:

Further, the present invention relates to an image display device having the flexible polarizing film.

The flexible polarizing film of the present invention uses a polyvinyl alcohol-based polarizer, and can satisfy versatility. Moreover, a polyvinyl alcohol-type polarizer is 10 micrometers or less in thickness, and it is preferable also from the point made thin.

In addition, the flexible polarizing film of the present invention has a high degree of flexibility despite using a polyvinyl alcohol-based polarizer that is soft and easily torn as a single unit, and cracks occur in the entire film even when the shape is deformed by applying torsion or No fold marks (fold traces) remain or light leakage occurs in the polarizer. In addition, the flexible polarizing film of the present invention may have flexibility with respect to various deformations such as stretching and bending. As described above, the flexible polarizing film of the present invention has flexibility in itself, and the tensile rupture stress of the conventional polyvinyl alcohol-based polarizer is significantly reduced by itself, making it practically impossible to handle. great.

In addition, the flexible polarizing film of the present invention has flexibility even when used in combination with or pasted together with other members by utilizing flexibility, can suppress cracks in the polarizer, and can be used for various applications. Accordingly, the use of the flexible polarizing film is greatly expanded due to the expansion of the application to the single flexible polarizing film, the expansion of the tolerance in the process, and the like. Therefore, the flexible polarizing film of the present invention can respond to a design that could not be applied as a substitute for a polarizer, for example, because it is soft and torn with a conventional polarizer, and a polarizing film (a polarizer with a transparent protective film installed on it) ), for example, it is possible to cope with various deformable shapes that cannot be applied due to the rigidity of the conventional polarizing film, and it is possible to expand the application development.

BRIEF DESCRIPTION OF THE DRAWINGS It is an example of the schematic sectional drawing of the flexible polarizing film of this invention.
Fig. 2 is a schematic diagram showing the state of a U-shape in a U-shaped stretch test.
3 is a schematic diagram showing a state of torsion in a torsion test.
4 is a schematic diagram showing a bending state in a bending holding test.
5 is a schematic diagram showing the degree of stiffness in the stiffness test.
6 is a schematic diagram showing a tensile test.

Hereinafter, the flexible polarizing film of the present invention will be described. The flexible polarizing film of the present invention has a polyvinyl alcohol-based polarizer.

<Polyvinyl alcohol-based polarizer>

In the polyvinyl alcohol-based polarizer, a polyvinyl alcohol-based resin is oriented in one direction (absorption axis direction), and iodine or a dichroic dye is adsorbed and oriented to the polyvinyl alcohol-based resin. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, partially formalized polyvinyl alcohol, and partially saponified ethylene/vinyl acetate copolymer. The polarizer can be obtained by uniaxially stretching by adsorbing iodine or a dichroic dye of a dichroic dye to a polyvinyl alcohol-based film using the polyvinyl alcohol-based resin.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine or a dichroic dye and uniaxially stretching, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine, dyeing, and stretching to 3 to 7 times the original length can be produced. If necessary, boric acid, zinc sulfate, zinc chloride, etc. may be included, and it can also be immersed in aqueous solutions, such as potassium iodide. Moreover, you may immerse a polyvinyl alcohol-type film in water and wash with water before dyeing as needed. By washing the polyvinyl alcohol-based film with water, contamination and blocking agents on the surface of the polyvinyl alcohol-based film can be washed, and by expanding the polyvinyl alcohol-based film, there is also an effect of preventing unevenness such as dyeing. Stretching may be performed after dyeing with iodine or a dichroic dye, or may be stretched while dyeing, or may be dyed with iodine or a dichroic dye after stretching. It can be extended also in aqueous solutions, such as boric acid and potassium iodide, and a water bath.

It is preferable from a viewpoint of extending|stretching stability or optical durability that polyvinyl alcohol type polarizer contains boric acid. In addition, the boric acid content contained in the polarizer is preferably 25% by weight or less with respect to the total amount of the polarizer from the viewpoint of suppressing the occurrence of light leakage, further preferably 20% by weight or less, further 18% by weight or less, further 16% by weight It is preferable that it is below. On the other hand, from a viewpoint of the extending|stretching stability of a polarizer, or optical durability, it is preferable that the boric acid content with respect to the whole amount of a polarizer is 10 weight% or more, Furthermore, it is preferable that it is 12 weight% or more.

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. It is preferable that the thickness of the said polarizer is 8 micrometers or less from a viewpoint of thickness reduction and flexibility, Furthermore, it is preferable that it is 7 micrometers or less, Furthermore, it is preferable that it is 6 micrometers or less. On the other hand, it is preferable that the thickness of a polarizer is 2 micrometers or more, Furthermore, it is 3 micrometers or more. Such a thin polarizer has less unevenness in thickness, excellent visibility, and less dimensional change, and thus has excellent durability against thermal shock.

Representatively, as a thin polarizer, Japanese Patent 4751486 Specification, Japanese Patent 4751481 Specification, Japanese Patent 4815544 Specification, Japanese Patent 5048120 Specification, International Publication No. 2014/077599 pamphlet, International Publication No. 2014/077636 The thin-shaped polarizer described in the pamphlet etc. or the thin-shaped polarizer obtained from the manufacturing method described in these is mentioned.

The polarizer has the following formula P>-(10 ^0.929T-42.4 -1)×100 (provided that T<42.3), or P≥99.9 (However, it is configured to satisfy the condition of T≥42.3). The polarizer configured to satisfy the above condition has the performance required as a display for liquid crystal TVs using a large-sized display element in one sense. Specifically, the contrast ratio is 1000:1 or more, and the maximum luminance is 500 cd/m 2 or more. As another use, it is pasted together by the visual recognition side of an organic electroluminescent display, for example.

On the other hand, since the polymer (for example, polyvinyl alcohol-based molecules) constituting the polarizer configured to satisfy the above conditions shows high orientation, it has a thickness of 10 µm or less and a direction perpendicular to the absorption axis direction of the polarizer (transmission axis). direction) is significantly reduced. As a result, for example, in a general polarizing film, the possibility that light leakage occurs in the direction of the absorption axis of the polarizer is extremely high. The flexible polarizing film of the present invention has excellent flexibility despite using a polyvinyl alcohol-based polarizer that is weak against impact with a thickness of 10 μm or less.

As the thin polarizer, among the manufacturing methods including the step of stretching in the state of a laminate and the step of dyeing, it can be stretched at a high magnification and the polarization performance can be improved, so Japanese Patent No. 4751486 and Japanese Patent No. 4751481 Specifications , is preferably obtained by a manufacturing method including a step of stretching in an aqueous boric acid solution as described in Japanese Patent No. 4815544, and particularly in the aqueous boric acid solution described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544. It is preferable to obtain by the manufacturing method including the process of carrying out aerial stretching auxiliary before extending|stretching. These thin polarizers can be obtained by a manufacturing method including a process of extending|stretching a polyvinyl alcohol-type resin (hereinafter also referred to as a PVA-type resin) layer and a resin base material for stretching in a laminated body state, and a process of dyeing|staining. If it is this manufacturing method, even if the PVA-type resin layer is thin, by being supported by the resin base material for extending|stretching, it becomes possible to extend|stretch without problems, such as a fracture|rupture by extending|stretching.

Further, the flexible polarizing film of the present invention is characterized in that there are no cracks, no folds, and no light leakage after the U-shaped stretching test specifically shown in Examples is performed. The U-shaped stretch test is an index indicating the flexibility related to the bendability under no load on the U-shape in the orientation direction (absorption axis direction) and orthogonal directions (transmission axis direction) in which the polyvinyl alcohol-based resin is oriented. It can be seen that the flexible polarizing film of the present invention has excellent flexibility related to bendability at no load in any direction of the absorption axis direction and the transmission axis direction by suppressing the occurrence of cracks, folds, and light leakage in the U-shaped stretching test. have.

The flexible polarizing film of the present invention is characterized in that there are no cracks, folds, or light leakage in the polyvinyl alcohol-based polarizer after the torsion test shown in the Examples is specifically performed. The torsion test is an index showing the flexibility in the twisted state in the orientation direction (absorption axis direction) in which the polyvinyl alcohol-based resin is oriented, which is prone to cracks, folds, and light leakage. It can be seen that the flexible polarizing film of the present invention does not have cracks, folds, and light leakage in a torsion test, and has excellent flexibility in a twisted state.

Moreover, it is preferable that the flexible polarizing film of this invention suppresses a crack while maintaining a bending shape after implementing the bending maintenance test specifically shown in an Example. In the bending maintenance test, the flexible polarizing film can maintain its original shape even when placed in a bent state by bending in the orientation direction (absorption axis direction) and orthogonal direction (transmission axis direction) in which the polyvinyl alcohol-based resin is oriented. It is an index indicating flexibility related to maintainability. It can be seen that the flexible polarizing film of the present invention has excellent retainability in both the absorption axis direction and the transmission axis direction by suppressing cracking while maintaining the bent shape in the bending holding test.

In addition, it is preferable that the flexible polarizing film of this invention specifically satisfy|fills 60 mm or less in the rigidity (mm) in the rigidity test shown in an Example. The stiffness test is an index indicating flexibility related to the bendability (low resistance to bending) in the orientation direction (absorption axis direction) and the orthogonal direction (transmission axis direction) in which the polyvinyl alcohol-based resin is oriented. It can be seen that the flexible polarizing film of the present invention has a stiffness of 60 mm or less and flexibility related to bending followability (low resistance to bending). Moreover, the said stiffness (mm) is an index|index showing the said flexibility, 50 mm or less is preferable, Furthermore, 40 mm or less is preferable. On the other hand, there is no particular limitation on the lower limit of the stiffness (mm).

Moreover, it is preferable that the tensile strength of the flexible polarizing film of this invention specifically, satisfy|fills 5 N/10mm or more in the tensile test shown in an Example. The tensile test is an index showing the strength in a direction (transmission axis direction) orthogonal to the orientation direction (absorption axis direction) in which the polyvinyl alcohol-based resin is oriented. It can be seen that the flexible polarizing film of the present invention has strength in the transmission axis direction by satisfying the tensile strength of 5N/10mm or more. Moreover, from a viewpoint of intensity|strength, 7 N/10mm or more is preferable, and, as for the said tensile strength, 10 N/10mm or more is more preferable.

Hereinafter, an example of the flexible polarizing film of this invention is demonstrated, referring FIG.

As the flexible polarizing film of the present invention, for example, one having a reinforcing film on both surfaces of a polyvinyl alcohol-based polarizer can be used. The flexible polarizing film 1 of FIG. 1 has a first reinforcing film b1 on a first surface of the polyvinyl alcohol-based polarizer 1 and a second reinforcing film b2 on the other second surface of the polyvinyl alcohol-based polarizer 1 . In the flexible polarizing film (1) of the present invention, the first reinforcing film (b1) and the second reinforcing film (b2) are provided directly on the polyvinyl alcohol-based polarizer (1).

The flexible polarizing film (1) of the present invention has flexibility in the U-shaped stretch test, and has a transparent protective film on one or both sides of the polyvinyl alcohol-based polarizer (a), and the flexibility cannot be satisfied. It is clearly distinguished from a polarizing film.

<Reinforcement film>

The thickness of the reinforcing film is preferably 15 µm or less, more preferably 10 µm or less, and further preferably 7 µm or less from the viewpoint of thinning and flexibility. On the other hand, the thickness of the reinforcing film is preferably 1 µm or more from the viewpoint of flexibility and strength, more preferably 3 µm or more, and further preferably 5 µm or more.

In addition, the ratio (t2/t1) of the thickness (t2) of the reinforcing film to the thickness (t1) of the polyvinyl alcohol-based polarizer is preferably 0.4 or more from the viewpoint of flexibility and strength, more preferably 0.6 or more, and further 0.8 more preferably. On the other hand, it is preferable that the said ratio (t2/t1) is 2.0 or less from a viewpoint of thinning, Furthermore, it is preferable that it is 1.5 or less, Furthermore, it is preferable that it is 1.2 or less.

In the case of having the first reinforcing film (b1) and the second reinforcing film (b2) on both sides of the polyvinyl alcohol-based polarizer (1), the reinforcing film is higher than the case of having the reinforcing film only on one side in the U-shaped stretching test, torsion test, etc. It is preferable at the point which can satisfy|fill more flexibility and the intensity|strength in a tensile test can be satisfied.

The thickness of each reinforcing film of the first reinforcing film b1 and the second reinforcing film b2 on both surfaces of the polyvinyl alcohol-based polarizer 1 may be the same or different, but the first reinforcing film b1 and the second reinforcing film b1 2 The difference in the thickness of the reinforcing film (b2) is equal to the stress in the flexible polarizing film in normal (a state where only the flexible polarizing film is left alone) and in the flexibility test (various tests such as U-shaped stretching test). The thickness is preferably 10 µm or less, more preferably 7 µm or less, further preferably 5 µm or less, and particularly preferably the same thickness.

The reinforcing film preferably has a compressive elastic modulus at 23° C. of 1 MPa or more from the viewpoint of strength. Further, the compressive elastic modulus of the reinforcing film is preferably 10 MPa or more, and further preferably 100 MPa or more. On the other hand, when the compressive elastic modulus of the reinforcing film layer increases, it tends to become too hard and the flexibility tends to deteriorate. Therefore, the compressive elastic modulus is preferably 10 GPa or less, and further preferably 1 GPa or less.

The reinforcing film may be formed from various forming materials. The reinforcing film can be formed, for example, by applying a resin material to the polyvinyl alcohol-based polarizer, or can _{also be formed by depositing an inorganic oxide such as SiO 2} on the polyvinyl alcohol-based polarizer by sputtering or the like. It is preferable that the reinforcing film is a resin film formed of a resin material from a viewpoint of forming easily.

The said reinforcing film may orientate, and it does not need to be orientating, and either can be used. When the reinforcing film is oriented, a phase difference occurs and the optical properties of the polyvinyl alcohol-based polarizer are changed. Therefore, when the optical properties of the polarizer are maintained, it is preferable that the reinforcing film is substantially not oriented. Substantially not oriented refers to a state in which an orientation exists in the reinforcing film due to the orientation of the polarizer, but a treatment for actively aligning the reinforcing film is not performed. The reinforcing film which is not substantially oriented can be formed by apply|coating the formation material of a resin film to a polyvinyl alcohol type polarizer, for example. On the other hand, the one oriented can be used as the reinforcing film. The orientated reinforcing film exhibits retardation and can be used as an optical compensation film or the like.

The material for forming the reinforcing film is not particularly limited as long as it is a material capable of close contact with the polyvinyl alcohol-based polarizer, and for example, polyester-based resin, polyether-based resin, polycarbonate-based resin, polyurethane-based resin, silicone-based resin, Polyamide-type resin, polyimide-type resin, PVA-type resin, an acrylic resin, an epoxy resin, etc. are mentioned. These resin materials can be used alone or in combination of two or more, but among them, at least one selected from the group consisting of polyurethane-based resins, PVA-based resins, acrylic resins, and epoxy resins is preferable, and polyurethane-based resins are preferred. Resin and acrylic resin are more preferable.

The reinforcing film can be formed by coating the surface of the polarizer, the resin component, or a liquid containing a curable component constituting the resin, and then solidifying or curing the liquid. In addition, there is no restriction|limiting in particular as long as the form of the coating liquid which is the said liquid shows a liquid phase, Any of a water system, a water dispersion system, a solvent system, and a non-solvent may be sufficient.

In addition, the forming material may contain an additive within a range that does not impair the function of the reinforcing film. For example, silane coupling agent, polyether compound of polyalkylene glycol such as polypropylene glycol, colorant, powder such as pigment, dye, surfactant, plasticizer, tackifier, antistatic agent, surface lubricant, leveling agent, softening agent, An antioxidant, an anti-aging agent, a light stabilizer, a ultraviolet absorber, a polymerization inhibitor, an inorganic or organic filler, a metal powder, a particulate form, a thin thing, etc. can be added suitably according to the use used. In addition, within a controllable range, a redox system to which a reducing agent is added may be employed.

It is advantageous that the liquid (coating liquid) has a lower viscosity. As for the said viscosity, it is preferable that the value measured at 25 degreeC is 2000 mPa*s or less, Furthermore, it is preferable that it is 1000 mPa*s or less, Furthermore, it is preferable that it is 500 mPa*s or less, Furthermore, it is preferable that it is 100 mPa*s or less.

In the formation of the reinforcing film, after the liquid containing the resin component is coated, the resin component is solidified according to the type. The liquid product containing the resin component is a solution or dispersion obtained by dissolving the resin component in a solvent, and is used, for example, as an aqueous solution, an aqueous dispersion, or a solvent solution. The said solidification refers to forming a resin layer by removing a solvent from the said liquid substance.

An aqueous resin emulsion can be used as the dispersion of the aqueous dispersion system. The water-based resin emulsion contains emulsion resin particles emulsified in water (dispersion medium). The reinforcing film of the present invention can be formed by directly applying the forming material including the water-based resin emulsion to the polarizer and drying it.

Although it does not specifically limit as resin which comprises the said emulsion resin, For example, an acrylic resin, a silicone resin, a polyurethane resin, a fluororesin, etc. are mentioned. Among these, in the present invention, polyurethane-based resins and acrylic resins are preferable in terms of excellent optical transparency and excellent weather resistance, heat resistance, and the like.

Examples of the water-based resin emulsion include Taisei Fine Chemicals trade name: SE-2915E (acrylic emulsion containing UV absorber), Toagosei Corporation trade name: Aron A-104, Aron A-106, and the like. have.

On the other hand, in the formation of the transparent resin layer, after the liquid material containing the curable component constituting the resin is coated, the curable component is cured to form a resin depending on the type of the curable component. . A liquid material containing a curable component constituting the resin may be used in a solvent-free system as long as the curable component represents a liquid material. In addition, as the liquid, a solution obtained by dissolving the curable component in a solvent may be used. Moreover, even when the said curable component shows a liquid thing, it can use as a solution. As said solvent, it can select suitably according to the sclerosing|hardenable component used. For example, when an acrylic monomer forming an acrylic resin is used as the curable component, or an epoxy monomer forming an epoxy resin is used, the liquid containing the curable component is irradiated with active energy rays (ultraviolet rays) Hardening by etc. can be performed.

About the reinforcing film, the curable forming material containing the curable component which can comprise resin is demonstrated. The curable component can be broadly classified into an active energy ray curing type such as an electron beam curing type, an ultraviolet curing type, and a visible ray curing type, and a thermal curing type. In addition, the ultraviolet curing type and the visible light curing type can be divided into a radical polymerization curing type and a cationic polymerization curing type. In the present invention, an active energy ray having a wavelength range of 10 nm to less than 380 nm is denoted as an ultraviolet ray, and an active energy ray having a wavelength range of 380 nm to 800 nm is denoted as a visible ray. The said radical polymerization curing type curable component can be used as a thermosetting type curable component.

≪Radical polymerization curing type forming material≫

As said sclerosing|hardenable component, a radically polymerizable compound is mentioned, for example. The compound which has a radically polymerizable functional group of carbon-carbon double bonds, such as a (meth)acryloyl group and a vinyl group, is mentioned as a radically polymerizable compound. As these sclerosing|hardenable components, either a monofunctional radically polymerizable compound or a bifunctional or more than bifunctional polyfunctional radically polymerizable compound can be used. In addition, these radically polymerizable compounds can be used individually by 1 type or in combination of 2 or more type. As these radically polymerizable compounds, the compound which has a (meth)acryloyl group is preferable, for example. In addition, in this invention, (meth)acryloyl means an acryloyl group and/or a methacryloyl group, and "(meth)" has the same meaning below.

≪Monofunctional radically polymerizable compound≫

As a monofunctional radically polymerizable compound, the (meth)acrylamide derivative which has a (meth)acrylamide group is mentioned, for example. A (meth)acrylamide derivative is preferable at the point which ensures adhesiveness with a polarizer and is excellent in productivity because a polymerization rate is fast. Specific examples of the (meth)acrylamide derivative include, for example, N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N-isopropyl ( N-alkyl group-containing (meth)acrylamide derivatives, such as meth)acrylamide, N-butyl (meth)acrylamide, and N-hexyl (meth)acrylamide; N-hydroxyalkyl group-containing (meth)acrylamide derivatives, such as N-methylol (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, and N-methylol-N-propane (meth)acrylamide; N-aminoalkyl group-containing (meth)acrylamide derivatives such as aminomethyl (meth)acrylamide and aminoethyl (meth)acrylamide; N-alkoxy group-containing (meth)acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide; N-mercaptoalkyl group-containing (meth)acrylamide derivatives such as mercaptomethyl (meth)acrylamide and mercaptoethyl (meth)acrylamide; and the like. Further, examples of the heterocycle-containing (meth)acrylamide derivative in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle include N-acryloylmorpholine, N-acryloylpiperidine, N-meth Acryloylpiperidine, N-acryloylpyrrolidine, etc. are mentioned.

Among the above (meth)acrylamide derivatives, from the viewpoint of adhesion to a polarizer, N-hydroxyalkyl group-containing (meth)acrylamide derivatives are preferable, and N-hydroxyethyl (meth)acrylamide is particularly preferable.

Moreover, as a monofunctional radically polymerizable compound, various (meth)acrylic acid derivatives which have a (meth)acryloyloxy group are mentioned, for example. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acryl rate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl ( Meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate (meth)acrylic acid (C 1-20) alkyl esters such as , 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, and n-octadecyl (meth) acrylate can be heard

Examples of the (meth)acrylic acid derivative include cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate;

Aralkyl (meth)acrylates, such as benzyl (meth)acrylate;

2-isobornyl (meth)acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl polycyclic (meth)acrylates such as (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentanyl (meth)acrylate;

2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol ( alkoxy group or phenoxy group-containing (meth)acrylates such as meth)acrylate, phenoxyethyl (meth)acrylate, and alkylphenoxypolyethylene glycol (meth)acrylate; and the like.

Moreover, as said (meth)acrylic acid derivative, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate ) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12- Hydroxyalkyl (meth) acrylates such as hydroxylauryl (meth) acrylate, [4- (hydroxymethyl) cyclohexyl] methyl acrylate, cyclohexane dimethanol mono (meth) acrylate, 2-hydr hydroxyl group-containing (meth)acrylates such as hydroxy-3-phenoxypropyl (meth)acrylate;

Epoxy group-containing (meth)acrylates, such as glycidyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate glycidyl ether;

2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth) halogen-containing (meth)acrylates such as acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, and 3-chloro-2-hydroxypropyl (meth)acrylate;

alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate;

3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth)acrylate, 3-ethyl-oxetanylmethyl (meth)acrylate, 3-butyl-oxetanylmethyl (meth) ) Oxetane group-containing (meth)acrylates such as acrylate and 3-hexyl-oxetanylmethyl (meth)acrylate;

(meth) acrylates having a heterocyclic ring such as tetrahydrofurfuryl (meth) acrylate and butyrolactone (meth) acrylate, hydroxypivalic acid neopentyl glycol (meth) acrylic acid adduct, p-phenylphenol ( meth)acrylate and the like.

Examples of the monofunctional radically 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.

Moreover, as a monofunctional radically polymerizable compound, For example, Lactam-type vinyl monomers, such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; and vinyl monomers having a nitrogen-containing heterocycle such as vinylpyridine, vinylpiperidine, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine. .

Moreover, as a monofunctional radically polymerizable compound, the radically polymerizable compound which has an active methylene group can be used. The radically polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acryl group at the terminal or in the molecule, and also having an active methylene group. Examples of the active methylene group include an acetoacetyl group, an alkoxymalonyl group, or a cyanoacetyl group. It is preferable that the said active methylene group is an acetoacetyl group. Specific examples of the radically polymerizable compound having an active methylene group include, for example, 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, 2-acetoacetoxy-1-methylethyl ( acetoacetoxyalkyl (meth)acrylates such as meth)acrylate; 2-ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxy) butyl) acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, N-(2-acetoacetylaminoethyl)acrylamide, etc. are mentioned. It is preferable that the radically polymerizable compound which has an active methylene group is acetoacetoxyalkyl (meth)acrylate.

«Polyfunctional radically polymerizable compound»

In addition, as a polyfunctional radically polymerizable compound more than bifunctional, for example, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 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)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecane Dimethanol di (meth) acrylate, cyclic trimethylol propane formal (meth) acrylate, dioxane glycol di (meth) acrylate, trimethylol propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate (meth)acrylic acid such as , pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, EO modified diglycerin tetra (meth) acrylate, An esterified product with a polyhydric alcohol and 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene are mentioned. Specific examples include Aronix M-220, M-306 (manufactured by Toagosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoei Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoei Chemical Co., Ltd.), light acrylate DCP-A (manufactured by Kyoei Chemical Corporation), SR-531 (manufactured by Sartomer Corporation), CD-536 (manufactured by Sartomer Corporation), and the like. Moreover, various epoxy (meth)acrylates, urethane (meth)acrylate, polyester (meth)acrylate, various (meth)acrylate type monomers, etc. are mentioned as needed.

It is preferable that a radically polymerizable compound uses together a monofunctional radically polymerizable compound and a polyfunctional radically polymerizable compound from a viewpoint of making adhesiveness with a polarizer and optical durability compatible. Usually, it is preferable to use together in the ratio of 3-80 weight% of monofunctional radically polymerizable compounds and 20 to 97 weight% of polyfunctional radically polymerizable compounds with respect to 100 weight% of radically polymerizable compounds.

«Aspects of a radical polymerization curing type forming material»

The radical polymerization curable forming material can be used as an active energy ray-curable or thermosetting forming material. When using an electron beam etc. for an active energy ray, the said active energy ray hardening type forming material does not need to contain a photoinitiator, but when using an ultraviolet-ray or visible light for an active energy ray, it is preferable to contain a photoinitiator. On the other hand, when using the said curable component as a thermosetting component, it is preferable that the said forming material contains a thermal polymerization initiator.

≪Photoinitiator≫

The photoinitiator in the case of using a radically polymerizable compound is suitably selected by an active energy ray. In the case of curing by ultraviolet or visible light, a photopolymerization initiator of ultraviolet or visible light cleavage is used. As said photoinitiator, For example, Benzophenone type compounds, such as benzyl, benzophenone, benzoylbenzoic acid, 3,3'- dimethyl-4- methoxybenzophenone; 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α - Aromatic ketone compounds, such as hydroxycyclohexylphenyl ketone; Methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane acetophenone-based compounds such as -1; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; aromatic ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalene sulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; Thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone thioxanthone compounds such as xanthone, 2,4-diisopropyl thioxanthone and dodecyl thioxanthone; camphorquinone; halogenated ketones; acylphosphine oxide; Acyl phosphonate, etc. are mentioned.

The compounding quantity of the said photoinitiator is 20 weight part or less with respect to 100 weight part of total amounts of a sclerosing|hardenable component (radically polymerizable compound). It is preferable that the compounding quantity of a photoinitiator is 0.01-20 weight part, Furthermore, it is 0.05-10 weight part, Furthermore, it is preferable that it is 0.1-5 weight part.

In the case of using the curable forming material as a visible ray curing type containing a radically polymerizable compound as a curable component, it is particularly preferable to use a photopolymerization initiator highly sensitive to light of 380 nm or more. A photoinitiator highly sensitive to light of 380 nm or more will be described later.

As said photoinitiator, the compound represented by following formula (1);

[Formula (1)]

(wherein, R ¹ and R ² represent -H, -CH ₂ CH ₃ , -iPr or Cl, and R ¹ and R ² may be the same or different), or Formula (1) It is preferable to use together the compound represented by and the photoinitiator which is highly sensitive with respect to the light of 380 nm or more mentioned later. When the compound represented by Formula (1) is used, it is excellent in adhesiveness compared with the case where the photoinitiator highly sensitive with respect to light of 380 nm or more was used alone. Among the compounds represented by the formula (1), diethylthioxanthone in which ^{R 1} and R ² are —CH ₂ CH _{3 is particularly preferable.} The composition ratio of the compound represented by the 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 0.9 to 3 parts by weight with respect to 100 parts by weight of the total amount of the curable component. It is more preferable to deny it.

Moreover, it is preferable to add a polymerization initiation adjuvant as needed. Examples of the polymerization initiation adjuvant include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and 4-dimethylaminobenzoate isoamyl. etc. are mentioned, 4-dimethylamino ethyl benzoate is especially preferable. When using a polymerization initiation adjuvant, the addition amount is 0-5 weight part normally with respect to 100 weight part of total amounts of a sclerosing|hardenable component, Preferably it is 0-4 weight part, Most preferably, it is 0-3 weight part.

Moreover, a well-known photoinitiator can be used together as needed. As a photoinitiator, it is preferable to use the highly sensitive photoinitiator with respect to the light of 380 nm or more. Specifically, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone -1,2-(Dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl- Diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro -3-(1H-pyrrol-1-yl)-phenyl) titanium and the like.

In particular, as a photoinitiator, in addition to the photoinitiator of formula (1), a compound further represented by the following formula (2);

[Formula (2)]

(wherein 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) It is preferable to use As the compound represented by the formula (2), a commercially available 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: IRGACURE907, manufacturer: BASF) is preferably used. It is possible. In addition, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name: IRGACURE369, manufacturer: BASF), 2-(dimethylamino)-2-[(4- Methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: IRGACURE379, manufacturer: BASF) is preferable because of its high sensitivity.

<Radically polymerizable compound having an active methylene group and a radical polymerization initiator having hydrogen abstraction>

In the active energy ray-curable forming material, when a radically polymerizable compound having an active methylene group is used as the radically polymerizable compound, it is preferably used in combination with a radical polymerization initiator having a hydrogen extraction action.

As a radical polymerization initiator with a hydrogen-drawing effect|action, a thioxanthone type radical polymerization initiator, a benzophenone type radical polymerization initiator, etc. are mentioned, for example. The radical polymerization initiator is preferably a thioxanthone radical polymerization initiator. As a thioxanthone-type radical polymerization initiator, the compound represented by said general formula (1) is mentioned, for example. Specific examples of the compound represented by the general formula (1) include thioxanthone, dimethyl thioxanthone, diethyl thioxanthone, isopropyl thioxanthone, and chlorothioxanthone. Among the compounds represented by the formula (1), diethylthioxanthone in which ^{R 1} and R ² are —CH ₂ CH _{3 is particularly preferable.}

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 hydrogen extraction action, when the total amount of the curable component is 100% by weight, the active methylene group It is preferable to contain 0.1 to 10 weight part of 1-50 weight% of the radically polymerizable compound which has, and a radical polymerization initiator with respect to 100 weight part of total amounts of a sclerosing|hardenable component.

≪Thermal polymerization initiator≫

As a thermal polymerization initiator, it is preferable that polymerization is not started by thermal cleavage when forming a reinforcing film. For example, as a thermal polymerization initiator, a 10-hour half-life temperature is 65 degreeC or more, Furthermore, it is preferable that it is 75-90 degreeC. In addition, this half-life is an index|index which shows the decomposition rate of a polymerization initiator, and means the time until the residual amount of a polymerization initiator becomes half. The decomposition temperature for obtaining a half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc., for example, "Organic Peroxide Catalog 9th Edition (May 2003) of Nippon Yushi Co., Ltd." ' and so on.

Examples of the thermal polymerization initiator include lauroyl peroxide (10-hour half-life temperature: 64°C), benzoyl peroxide (10-hour half-life temperature: 73°C), 1,1-bis(t-butylperoxy)-3,3 ,5-trimethylcyclohexane (10 hour half-life temperature: 90°C), di(2-ethylhexyl)peroxydicarbonate (10 hour half-life temperature: 49°C), di(4-t-butylcyclohexyl)peroxydicarbonate; Di-sec-butylperoxydicarbonate (10 hour half-life temperature: 51°C), t-butylperoxyneodecanoate (10 hour half-life temperature: 48°C), t-hexylperoxypivalate, t-butylperoxy Pivalate, dilauroyl peroxide (10 hours half-life temperature: 64°C), di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (10 hours) Half-life temperature: 66°C), di(4-methylbenzoyl)peroxide, dibenzoyl peroxide (10 hour half-life temperature: 73°C), t-butylperoxyisobutyrate (10 hour half-life temperature: 81°C), 1, and organic peroxides such as 1-di(t-hexylperoxy)cyclohexane.

As the thermal polymerization initiator, for example, 2,2'-azobisisobutyronitrile (10 hour half-life temperature: 67°C), 2,2'-azobis(2-methylbutyronitrile) (10 hour half-life) azo compounds such as temperature: 67°C) and 1,1-azobis-cyclohexane-1-carbonitrile (10 hour half-life temperature: 87°C).

The compounding quantity of a thermal polymerization initiator is 0.01-20 weight part with respect to 100 weight part of total amounts of a sclerosing|hardenable component (radically polymerizable compound). The compounding quantity of a thermal polymerization initiator is 0.05-10 weight part further, Furthermore, it is preferable that it is 0.1-3 weight part.

≪Cation polymerization curing type forming material≫

As a sclerosing|hardenable component of a cationic polymerization hardening type forming material, the compound which has an epoxy group and oxetanyl group is mentioned. 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 generally known curable epoxy compounds can be used. As a preferred epoxy compound, a compound having at least two epoxy groups and at least one aromatic ring in the molecule (aromatic epoxy compound), or two adjacent compounds having at least two epoxy groups in the molecule and at least one of them constituting an alicyclic ring The compound (alicyclic epoxy compound) etc. which are formed between two carbon atoms are mentioned.

«Photocationic polymerization initiator»

The cationic polymerization curable forming material contains the above-described epoxy compound and oxetane compound as curable components, and since both of these are cured by cationic polymerization, a photocationic polymerization initiator is blended. This photocationic polymerization initiator generates cationic species or Lewis acid by irradiation with active energy rays such as visible light, ultraviolet light, X-ray, electron beam, and the like, and initiates a polymerization reaction of an epoxy group or an oxetanyl group.

<Other ingredients>

The curable forming material according to the present invention preferably contains the following components.

<Acrylic oligomer>

The active energy ray-curable forming material according to the present invention may contain an acrylic oligomer obtained by polymerizing a (meth)acrylic monomer in addition to the curable component related to the radically polymerizable compound. By containing the acrylic oligomer in the active energy ray-curable forming material, curing shrinkage at the time of irradiating and curing the reinforcing film with an active energy ray can be reduced, thereby reducing the interfacial stress between the reinforcing film and the polarizer. In order to fully suppress cure shrinkage, it is preferable that it is 20 weight part or less, and, as for content of an acrylic oligomer with respect to 100 weight part of total amounts of a curable component, it is more preferable that it is 15 weight part or less. When there is too much content of the acrylic oligomer in a forming material, the fall of the reaction rate at the time of irradiating an active energy ray to this forming material may become severe and hardening may become poor. On the other hand, it is preferable to contain 3 weight part or more of acrylic oligomers with respect to 100 weight part of total amounts of a sclerosing|hardenable component, and it is more preferable to contain 5 weight part or more.

Since the active energy ray-curable forming material preferably has a low viscosity in consideration of workability and uniformity during coating, the acrylic oligomer formed by polymerizing a (meth)acrylic monomer also preferably has a low viscosity. As the acrylic oligomer having low viscosity and capable of preventing curing shrinkage of the reinforcing film, the weight average molecular weight (Mw) is preferably 15,000 or less, more preferably 10,000 or less, and particularly preferably 5,000 or less. On the other hand, in order to sufficiently suppress cure 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 particularly preferably 1,500 or more. Specific examples of the (meth)acrylic monomer constituting the acrylic oligomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, 2- Methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, S-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylic (meth)acrylic acid such as late, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, and N-octadecyl (meth) acrylate (C 1-20) Alkyl esters, for example, cycloalkyl (meth) acrylic acid (for example, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), aralkyl (meth) acrylic rate (eg, benzyl (meth) acrylate, etc.), polycyclic (meth) acrylate (eg, 2-isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5 -norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, etc.), hydroxyl group-containing (meth) acrylic acid esters (for example, hydroxy Ethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate, etc.), (meth)acrylic acid esters containing an alkoxy group or a phenoxy group (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth)acrylate, phenoxyethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic acid esters (eg glycidyl (meth)acrylate, etc.), halogen-containing (meth)acrylic acid esters (eg For example, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl ( Meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, etc.), alkylamino Alkyl (meth)acrylate (For example, dimethylaminoethyl (meth)acrylate etc.) etc. are mentioned. These (meth)acrylates can be used individually or in combination of 2 or more types. Specific examples of the acrylic oligomer include "ARUFON" by Toagosei Corporation, "Actflow" by Soken Chemicals, and "JONCRYL" by BASF Japan.

<Mining generator>

The said active energy ray hardening type forming material WHEREIN: A photo-acid generator can be contained. When the photo-acid generator is included 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 included. The photoacid generator may be represented by the following formula (3):

[Formula (3)]

L ⁺ X ^-

(However, L ⁺ represents any onium cation. X ^- represents PF ₆ ^- , SbF ₆ ^- , AsF ₆ ^- , SbCl ₆ ^- , BiCl ₅ ^- , SnCl ₆ ^- , ClO ₄ ^- , dithiocarbamate It represents a counter anion selected from the group consisting of ^a) an anion, SCN.

Specific examples of the preferred onium salt constituting the photoacid generator include PF ₆ ^- , SbF ₆ ^- , AsF ₆ ^- , SbCl ₆ ^- , BiCl ₅ ^- , SnCl ₆ ^- , ClO ₄ ^- , dithiocarbamate anion, SCN ^- It is an onium salt consisting of an anion.

Specifically, "Cyracure UVI-6992", "Cyracure UVI-6974" (above, manufactured by Dow Chemical Japan Co., Ltd.), "Adeka Optoma-SP150", "Adeka Optoma-SP152", "A Deca Optoma SP170", "Adeka Optoma SP172" (above, manufactured by ADEKA Co., Ltd.) "IRGACURE250" (manufactured by Ciba Specialty Chemicals), "CI-5102", "CI-2855" (above, manufactured by Nippon Soda), " “San-Aid SI-60L”, “San-Aid SI-80L”, “San-Aid SI-100L”, “San-Aid SI-110L”, “San-Aid SI-180L” (above, manufactured by Sanshin Chemical), “CPI- 100P”, “CPI-100A” (above, manufactured by San Apro Corporation), “WPI-069”, “WPI-113”, “WPI-116”, “WPI-041”, “WPI-044”, “WPI- 054", "WPI-055", "WPAG-281", "WPAG-567", and "WPAG-596" (above, manufactured by Wako Pure Chemical Industries, Ltd.) are mentioned as a preferable specific example of a photo-acid generator.

Content of a photo-acid generator is 10 weight part or less with respect to 100 weight part of total amounts of sclerosing|hardenable component, It is preferable that it is 0.01-10 weight part, It is more preferable that it is 0.05-5 weight part, It is especially preferable that it is 0.1-3 weight part. .

Formation of the reinforcing film with the said curable forming material is made by coating a curable forming material on the surface of a polarizer, and hardening after that.

The polarizer may be subjected to a surface modification treatment before coating the curable forming material. Specific examples of the treatment include corona treatment, plasma treatment, and treatment by saponification treatment.

The coating method of the curable forming material is appropriately selected depending on the viscosity of the curable forming material or the desired thickness. As an example of a coating method, a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater etc. are mentioned, for example. In addition, a method such as a dipping method may be appropriately used for coating.

<Curing of the forming material>

The curable forming material is used as an active energy ray-curable forming material or a thermosetting forming material. In an active energy ray-curable forming material, it can use in the aspect of an electron beam hardening type, an ultraviolet curable type, and a visible ray hardening type.

≪Active energy ray curing type≫

In the active energy ray-curable former, after the active energy ray-curable former is coated on a polarizer, an active energy ray (electron beam, ultraviolet ray, visible ray, etc.) is irradiated, and the active energy ray-curable former is cured to form a reinforcing film. The irradiation direction of active energy rays (electron beam, ultraviolet light, visible light, etc.) can be irradiated from any suitable direction. Preferably, it is irradiated from the side of the reinforcement film.

≪Electron beam curing type≫

In the electron beam curing type, any suitable condition can be adopted as the electron beam irradiation condition as long as it is a condition capable of curing the active energy ray curing type forming material. For example, the accelerating voltage of electron beam irradiation is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the accelerating voltage is less than 5 kV, the electron beam does not reach the deepest part of the reinforcing film and there is a risk of insufficient curing, and if the accelerating voltage exceeds 300 kV, the penetrating force through the sample is too strong and there is a risk of damaging the polarizer . As an irradiation dose, it is 5-100 kGy, More preferably, it is 10-75 kGy. When the irradiation dose is less than 5 kGy, the adhesive becomes insufficiently cured, and when it exceeds 100 kGy, the polarizer is damaged, resulting in deterioration of mechanical strength or yellowing, so that the desired optical properties cannot be obtained.

The electron beam irradiation is usually carried out in an inert gas, but if necessary, it may be carried out in the atmosphere or a condition in which oxygen is introduced slightly.

≪Ultraviolet light curing type, visible light curing type≫

As the active energy ray, it is preferable to use an active energy ray containing visible ray having a wavelength range of 380 nm to 450 nm, particularly an active energy ray having the largest amount of irradiation of visible ray having a wavelength range of 380 nm to 450 nm. As the active energy ray, a gallium-encapsulated metal halide lamp or an LED light source emitting light in a wavelength range of 380 to 440 nm is preferable. or low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, extra high pressure mercury lamp, incandescent bulb, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excimer laser or sunlight. A light source including a light source may be used, and a band-pass filter may be used to block ultraviolet rays having a wavelength shorter than 380 nm.

≪Thermal curing type≫

On the other hand, the thermosetting type forming material is applied to a polarizer and then heated to initiate polymerization with a thermal polymerization initiator to form a cured product layer (reinforcing film). Although the heating temperature is set according to the thermal polymerization initiator, it is about 60-200 degreeC, Preferably it is 80-150 degreeC.

Moreover, as a material which forms the said reinforcement film, a cyanoacrylate type forming material, an epoxy type forming material, or an isocyanate type forming material can be used, for example.

Examples of the cyanoacrylate-based forming material include alkyl such as methyl-α-cyanoacrylate, ethyl-α-cyanoacrylate, butyl-α-cyanoacrylate, and octyl-α-cyanoacrylate. -α-cyanoacrylate, cyclohexyl-α-cyanoacrylate, methoxy-α-cyanoacrylate, and the like. As a cyanoacrylate-type forming material, what is used as a cyanoacrylate-type adhesive agent can be used, for example.

The epoxy-based forming material may be used alone as an epoxy resin, or may contain an epoxy curing agent. When using an epoxy resin individually, it hardens by adding a photoinitiator and irradiating an active energy ray. When an epoxy curing agent is added as the epoxy-based forming material, for example, one used as an epoxy-based adhesive can be used. The epoxy-based forming material may be used as a one-component type containing an epoxy resin and a curing agent, but may be used as a two-component type containing an epoxy resin and a curing agent. Epoxy-based forming materials are usually used as a solution. A solvent system may be sufficient as a solution, and aqueous systems, such as an emulsion, colloidal dispersion liquid, and aqueous solution, may be sufficient as it.

As the epoxy resin, various compounds containing two or more epoxy groups in the molecule can be exemplified, for example, a bisphenol type epoxy resin, an aliphatic type epoxy resin, an aromatic type epoxy resin, a halogenated bisphenol type epoxy resin, a biphenyl type epoxy resin and the like. In addition, although an epoxy resin can be suitably determined according to an epoxy equivalent and the number of functional groups, from a durable viewpoint, a thing with an epoxy equivalent of 500 or less is used preferably.

The curing agent for the epoxy resin is not particularly limited, and various curing agents such as phenol resins, acid anhydrides, carboxylic acids and polyamines can be used. As a phenol resin hardening|curing agent, a phenol novolak resin, a bisphenol novolak resin, a xylylene phenol resin, cresol novolak resin etc. are used, for example. As an acid anhydride type hardening|curing agent; and maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and succinic anhydride. Examples of the carboxylic acid-based curing agent include carboxylic acids such as pyromellitic acid and trimellitic acid, and block carboxylic acids to which vinyl ether is added. have. Moreover, as an epoxy-type two-component forming material, the thing which consists of two liquids of an epoxy resin and polythiol, the thing which consists of two liquids of an epoxy resin and polyamide, etc. can be used, for example.

Although the compounding quantity of a hardening|curing agent changes with the equivalent with an epoxy resin, it is 30-70 weight part with respect to 100 weight part of epoxy resins, Furthermore, it is preferable to set it as 40-60 weight part.

In addition to the epoxy resin and its curing agent, various curing accelerators can be used for the epoxy-based forming material. As a hardening accelerator, various imidazole type compounds, its derivative(s), dicyandiamide, etc. are mentioned, for example.

As an isocyanate type forming material, what is used as a crosslinking agent in formation of an adhesive layer is mentioned. As the isocyanate-based crosslinking agent, a compound having at least two isocyanate groups can be used. For example, the polyisocyanate compound can be used as an isocyanate-based forming material. Specifically, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, 1,3-bisisocyanatomethylcyclohexane, hexamethylene diisocyanate, tetramethylxylylene diisocyanate, m- Trimers such as isopropenyl-α,α-dimethylbenzyl isocyanate, methylenebis4-phenylisocyanate, p-phenylene diisocyanate or dimers thereof, tris(6-isocyanatehexyl) isocyanurate, and further burettes thereof (biuret) and polyhydric alcohols, such as trimethylol propane, what made it react with polyhydric amine, etc. are mentioned. Moreover, as an isocyanate type crosslinking agent, what has 3 or more isocyanate groups, such as isocyanuric-acid tris (6-isocyanate hexyl), is preferable. As an isocyanate-type forming material, what is used as an isocyanate-type adhesive agent is mentioned, for example.

Among the isocyanate-based forming materials, in the present invention, it is preferable to use a rigid structure in which a molecular structure (such as a benzene ring, a cyanurate ring, an isocyanurate ring) occupies a large proportion in the structure. As the isocyanate-based forming material, for example, trimethylolpropane-tri-tolylene isocyanate, tris(hexamethylene isocyanate) isocyanurate, or the like is preferably used.

In addition, the isocyanate-based crosslinking agent may be used in which a protecting group is imparted to a terminal isocyanate group. Examples of the protecting group include oxime and lactam. What has protected the isocyanate group causes the isocyanate group to react by dissociating the protecting group from the isocyanate group by heating.

In addition, in order to increase the reactivity of the isocyanate group, a reaction catalyst may be used. The reaction catalyst is not particularly limited, but a tin-based catalyst or an amine-based catalyst is preferable. The reaction catalyst can use 1 type or 2 or more types. The amount of the reaction catalyst is generally used in an amount of 5 parts by weight or less based on 100 parts by weight of the isocyanate-based crosslinking agent. When the reaction catalyst amount is large, the crosslinking reaction rate is increased, and foaming of the forming material occurs. Even if the forming material after foaming is used, sufficient adhesiveness cannot be obtained. Usually, when using a reaction catalyst, 0.01-5 weight part is preferable, Furthermore, 0.05-4 weight part is preferable.

As the tin-based catalyst, either an inorganic or organic catalyst can be used, but an organic catalyst is preferable. Examples of the inorganic tin-based catalyst include stannous chloride and stannous chloride. The organic tin catalyst preferably has at least one organic group such as an aliphatic group or an alicyclic group having a skeleton such as a methyl group, an ethyl group, an ether group, or an ester group. Examples thereof include tetra-n-butyltin, tri-n-butyltin acetate, n-butyltin trichloride, trimethyltin hydroxide, dimethyltin dichloride, and dibutyltin dilaurate.

In addition, it does not restrict|limit especially as an amine catalyst. For example, it is preferable to have at least one organic group such as an alicyclic group such as quinuclidine, amidine or diazabicycloundecene. In addition, triethylamine etc. are mentioned as an amine catalyst. In addition, as a reaction catalyst other than the above, cobalt naphthenate, benzyl trimethylammonium hydroxide, etc. can be illustrated.

The isocyanate-based former is usually used as a solution. A solvent system may be sufficient as a solution, and aqueous systems, such as an emulsion, colloidal dispersion liquid, and aqueous solution, may be sufficient as it. The organic solvent is not particularly limited as long as the components constituting the forming material are uniformly dissolved. As an organic solvent, toluene, methyl ethyl ketone, ethyl acetate etc. are mentioned, for example. Moreover, also when setting it as aqueous system, for example, alcohols, such as n-butyl alcohol and isopropyl alcohol, and ketones, such as acetone, can also be mix|blended. In the case of water-based formulation, a dispersing agent is used, or a functional group having low reactivity with an isocyanate group such as a carboxylic acid salt, a sulfonic acid salt, or a quaternary ammonium salt, or a water-dispersible component such as polyethylene glycol may be introduced into the isocyanate-based crosslinking agent.

The formation (curing) of the reinforcing film using the cyanoacrylate-based former, the epoxy-based former, or the isocyanate-based former can be appropriately selected depending on the type of the above-mentioned former, but is usually about 30 to 100°C, preferably is made by drying at 50 to 80° C. for about 0.5 to 15 minutes. In addition, in the case of the cyanoacrylate-based forming material, the reinforcing film can be formed in a shorter time than the above time because curing is fast.

In addition, polyurethane may be used as a material for forming the reinforcing film. For polyurethane, it is preferable to use a high molecular polyol compound and/or a reaction product of a low molecular polyol and an isocyanate compound. In addition, the polyurethane may be reacted with a low molecular weight polyamino compound and/or a polyol compound as a chain extender in addition to the high molecular weight polyol compound and the isocyanate compound.

The polymer polyol compound has a weight average molecular weight of 100 to 4,000, preferably having two or more hydroxyl groups in one molecule, and polyether polyol, polyester polyol, polycarbonate polyol and the like are used. As said polymeric polyol compound, 500-4,000 are preferable, and, as for a weight average molecular weight, it is preferable that it is 600-3,500, and it is more preferable that it is 1,000-3,000.

Examples of the polyether polyol include aliphatic polyether polyol and aromatic polyether polyol. More specifically, for example, dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and hexamethylene glycol; trihydric alcohols such as trimethylolpropane, glycerin, and pentaerythritol; Polyether formed by addition polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc. is used. These may be used independently, or 2 or more types may be mixed and used for them.

Examples of the polyester polyol include aliphatic polyester polyol and aromatic polyester polyol. More specifically, alcohols such as the above dihydric alcohols, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol, and dibasic acids such as adipic acid, azelaic acid, and sebacic acid Polyester consisting of a polycondensate is used. These may be used independently and may mix and use 2 or more types.

In addition, polybutadiene having hydroxyl groups at both ends of the molecule, butadiene/acrylonitrile copolymer, polydiene-based polyols such as polyisoprene, polybutadiene hydrogenated products having hydroxyl groups at both ends of the molecule, poly Polyolefin-type polyols, such as an isoprene hydrogenated product and polyisobutylene, etc. are mentioned.

Moreover, as a polyamino compound used as said chain extender, an aliphatic polyamino compound and an aromatic polyamino compound are mentioned. More specifically, for example, ethylenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), diethyltoluenediamine (DETDA), 4,4'-bis- (sec- butyl)diphenylmethane, 2,4-tolylenediamine, 2,6-tolylenediamine, xylylenediamine, hexanediamine, isophoronediamine, and the like. In particular, ethylenediamine and the like are preferable. These may be used independently and may mix and use 2 or more types.

Moreover, as a polyol compound used as said low molecular polyol and a chain extender, the low molecular polyol illustrated by polyether polyol and polyester polyol is mentioned.

The chain extender is preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.5 to 7 parts by weight, and still more preferably 1 to 5 parts by weight, based on 100 parts by weight of the polymer polyol compound. By using a chain extender, the molecular weight can be sufficiently raised to improve durability.

The isocyanate compound is a polyisocyanate (isocyanate compound) having two or more isocyanate groups, and the same as that of the isocyanate-based forming material can be used. The isocyanate compound can also be used as a urethane prepolymer in which the low molecular weight polyol exemplified by the polyester polyol and the isocyanate compound exemplified above are reacted in advance.

In addition, in order to react the isocyanate group and hydroxyl group of these polyisocyanates, it is preferable to use dibutyltin dilaurate, tin octoate, 1,4-diazabicyclo(2,2,2)octane etc. as a catalyst.

Formation (curing) of a reinforcing film with polyurethane may be performed by applying a liquid (coating solution) of polyurethane prepared in advance to a polarizer, or a composition containing the polymer polyol compound and an isocyanate compound A reinforcing film may be formed of polyurethane as a reactant cured after being coated on a polarizer. Formation of the reinforcing film can be accomplished by drying at about 30 to 100° C., preferably at 50 to 80° C. for about 0.5 to 15 minutes.

In addition, after the formation of the reinforcing film (curing: this is referred to as initial curing), an annealing treatment may be performed. The annealing treatment can be performed for the purpose of accelerating the reaction, particularly in an isocyanate-based former, a polyurethane-based former, and the like, when the isocyanate does not sufficiently react even after initial curing (a state in which a reactive group remains in the reinforcing film). The annealing treatment can be performed in any atmosphere of dry conditions or humid conditions. The annealing treatment temperature is about 30 to 100°C, preferably 50 to 80°C, similar to the conditions at the time of initial curing. There is no particular limitation on the annealing time.

Moreover, it is preferable that the weight average molecular weights of polyurethane are 30,000-200,000, It is more preferable that it is 40,000-150,000, It is still more preferable that it is 50,000-130,000.

(Measurement of weight average molecular weight)

The weight average molecular weight of the high molecular weight polyol compound and polyurethane was measured by GPC (gel permeation chromatography) under the following conditions.

Analysis apparatus: Tosoh Corporation make, HLC-8120GPC.

Column: Tosoh Corporation make, G7000HXL+GMHXL+GMHXL.

Column size: each 7.8 mm Φ × 30 cm total 90 cm.

Column temperature: 40°C.

Flow rate: 0.8 ml/min.

Injection volume: 100 μl.

Eluent: tetrahydrofuran.

Detector: Differential Refractometer.

Standard sample: polystyrene.

In addition, as a material for forming a reinforcing film, it has a functional group capable of forming a covalent bond with PVA such as an isocyanate group and an epoxy group, and has a radically polymerizable functional group of a carbon-carbon double bond such as a (meth)acryloyl group and a vinyl group compounds may be used. Examples of the compound include 2-isocyanatoethyl acrylate (manufactured by Showa Denko Corporation, product name Karenz AOI), and 1,1-(bisacryloyloxymethyl)ethyl isocyanate (manufactured by Showa Denko Corporation, Carenz AOI). lens BEI) and the like. Moreover, as said compound, the reaction product of the polymer which has a diisocyanate compound as a structural component, and hydroxyl-containing (meth)acrylate, etc. can be used. Examples of such a reaction product include a reaction product of 2-hydroxyethyl acrylate and a polymer containing 1,6-diisocyanatohexane as a constituent component (manufactured by BASF, product name Laroma LR9000).

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

In addition, the reinforcing film may be formed from the forming material which does not contain a sclerosing|hardenable component, and may be formed from the forming material containing the said polyvinyl alcohol-type resin as a main component, for example. 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”.

As said polyvinyl alcohol-type resin, polyvinyl alcohol is mentioned, for example. Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. Moreover, as a polyvinyl alcohol-type resin, the saponified material of the copolymer of vinyl acetate and the monomer which has copolymerization is mentioned. When the monomer having the copolymerizability is ethylene, an ethylene-vinyl alcohol copolymer may be obtained. Moreover, as a monomer which has the said copolymerization property, unsaturated carboxylic acids, such as (anhydride) maleic acid, a fumaric acid, a crotonic acid, itaconic acid, (meth)acrylic acid, and its ester; α-olefins such as ethylene and propylene, (meth)allylsulfonic acid (soda), sodium sulfonic acid (monoalkyl maleate), sodium disulfonic acid alkyl maleate, N-methylolacrylamide, acrylamide alkylsulfonic acid alkali salt, N- Vinylpyrrolidone, N-vinylpyrrolidone derivatives, etc. are mentioned. These polyvinyl alcohol-type resins can be used individually by 1 type or in combination of 2 or more types. Polyvinyl alcohol obtained by saponifying polyvinyl acetate is preferable from the viewpoint of satisfying heat-and-moisture resistance and water resistance by controlling the heat of crystal fusion of the reinforcing film to 30 mJ/mg or more.

The degree of saponification of the polyvinyl alcohol-based resin may be, for example, 95% or more, but from the viewpoint of satisfying heat-and-moisture resistance and water resistance by controlling the heat of crystal fusion of the reinforcing film to 30 mJ/mg or more, the degree of saponification is 99.0 % or more is preferable, and 99.7% or more is more preferable. The degree of saponification indicates the ratio of units that are actually saponified to vinyl alcohol units among units that can be converted to vinyl alcohol units by saponification, and the residue is a vinyl ester unit. The degree of saponification can be obtained according to JIS K 6726-1994.

The average degree of polymerization of the polyvinyl alcohol-based resin may be, for example, 500 or more, but the average degree of polymerization is 1,000 or more from the viewpoint of satisfying heat-and-moisture resistance and water resistance by controlling the heat of crystal fusion of the reinforcing film to 30 mJ/mg or more. Preferably, 1,500 or more are preferable, and 2,000 or more are further preferable. The average degree of polymerization of the polyvinyl alcohol-based resin is measured according to JIS-K 6726.

Moreover, as said polyvinyl alcohol-type resin, the modified polyvinyl alcohol-type resin which has a hydrophilic functional group in the side chain of the said polyvinyl alcohol or its copolymer can be used. As said hydrophilic functional group, an acetoacetyl group, a carbonyl group, etc. are mentioned, for example. In addition, polyvinyl alcohol modified by acetalization, urethanization, etherification, grafting, phosphoric acid esterification, and the like of polyvinyl alcohol-based resin may be used.

The forming material containing the polyvinyl alcohol-based resin as a main component may contain a curable component (crosslinking agent) or the like. It is preferable that the ratio of the polyvinyl alcohol-type resin in a reinforcing film or a forming material (solid content) is 80 weight% or more, Furthermore, it is preferable that it is 90 weight% or more, Furthermore, it is preferable that it is 95 weight% or more. However, it is preferable not to contain a curable component (crosslinking agent) in the said forming material from a viewpoint of being easy to control the amount of heat of crystal fusion of a reinforcing film to 30 mJ/mg or more.

As a crosslinking agent, the compound which has polyvinyl alcohol-type resin and at least 2 functional groups which have reactivity can be used. alkylenediamines having an alkylene group and two amino groups, such as ethylenediamine, triethylenediamine, and hexamethylenediamine; Tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropantorylene diisocyanate adduct, triphenylmethane triisocyanate, methylenebis(4-phenylmethane triisocyanate, isophorone diisocyanate, and their ketone oxime block products or phenol block products, etc. isocyanates of: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether Epoxy such as cydylaniline and diglycidylamine; Monoaldehyde such as formaldehyde, acetaldehyde, propionaldehyde and butylaldehyde; Glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde, maleindialdehyde dialdehydes such as , phthaldialdehyde, amino-formaldehyde resins such as methylol urea, methylol melamine, alkylated methylol urea, alkylated methylolated melamine, acetoguanamine, and a condensate of benzoguanamine and formaldehyde; Adipic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide Dicarboxylic acid dihydrazide such as hydrazide and itaconic acid dihydrazide Water-soluble dihydrazine such as ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine and butylene-1,4-dihydrazine Among these, amino-formaldehyde resin and water-soluble dihydrazine are preferable.As amino-formaldehyde resin, the compound having a methylol group is preferable.In particular, the compound having a methylol group, methylolmelamine, is particularly preferable. .

The curable component (crosslinking agent) may be used from the viewpoint of improving water resistance, but the ratio is preferably 20 parts by weight or less, 10 parts by weight or less, and 5 parts by weight or less with respect to 100 parts by weight of the polyvinyl alcohol-based resin.

The forming material is prepared by dissolving the polyvinyl alcohol-based resin in a solvent. Examples of the solvent include polyhydric alcohols such as water, dimethylsulfoxide, dimethylformamide, dimethylacetamide N-methylpyrrolidone, various glycols and alcohols, and amines such as ethylenediamine and diethylenetriamine. can These can be used individually or in combination of 2 or more types. Among these, it is preferable to use as an aqueous solution using water as a solvent. The concentration of the polyvinyl alcohol-based resin in the forming material (eg, aqueous solution) is not particularly limited, but in consideration of coatability and standing stability, 0.1 to 15% by weight, preferably 0.5 to 10% by weight to be.

Moreover, as an additive which can be mix|blended with the said forming material (for example, aqueous solution), a plasticizer, surfactant, etc. are mentioned, for example. As a plasticizer, polyhydric alcohol, such as ethylene glycol and glycerol, is mentioned, for example. As surfactant, a nonionic surfactant is mentioned, for example.

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 any suitable method can be employed. For example, various means such as roll coating method, spin coating method, wire bar coating method, dip coating method, die coating method, curtain coating method, spray coating method, knife coating method (comma coating method, etc.) can be adopted. .

<Surface treatment layer>

A surface treatment layer may be provided on one or both surfaces of the flexible polarizing film of the present invention. As said surface treatment layer, a hard-coat layer, an anti-glare treatment layer, an antireflection layer, a sticking prevention layer, etc. are mentioned. It is preferable that it is a hard-coat layer as said surface treatment layer. As a material for forming the hard coat layer, for example, a thermoplastic resin, 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 which can efficiently form a cured resin layer by a simple processing operation by hardening by ultraviolet irradiation is preferable. Examples of these curable resins include various types of resins such as polyester, acrylic, urethane, amide, silicone, epoxy, and melamine, and include monomers, oligomers and polymers thereof.

Moreover, as said surface treatment layer, the anti-glare treatment layer and antireflection layer for the purpose of improvement of visibility can be provided. Moreover, an anti-glare treatment layer and an anti-reflection layer can be provided on the said hard-coat layer. It does not specifically limit as a constituent material of an anti-glare treatment layer, For example, a radiation-curable resin, a thermosetting resin, a thermoplastic resin, etc. can be used. As the antireflection layer, titanium oxide, zirconium oxide, silicon oxide, magnesium fluoride, or the like is used. The antireflection layer can provide multiple layers. In addition, as a surface treatment layer, a sticking prevention layer etc. are mentioned.

Although the thickness of the said surface treatment layer can be set suitably according to the kind of surface treatment layer, it is generally preferable that it is 0.1-100 micrometers. For example, it is preferable that the thickness of a hard-coat layer is 0.5-20 micrometers.

<Adhesive layer>

An adhesive layer may be provided on one side or both sides of the flexible polarizing film of the present invention. An appropriate pressure-sensitive adhesive may be used to form the pressure-sensitive adhesive layer, and the type thereof is not particularly limited. Examples of the pressure-sensitive adhesive include a rubber pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a vinyl alkyl ether pressure-sensitive adhesive, a polyvinyl alcohol-based pressure-sensitive adhesive, a polyvinylpyrrolidone pressure-sensitive adhesive, a polyacrylamide pressure-sensitive adhesive, and a cellulose pressure-sensitive adhesive.

Among these pressure-sensitive adhesives, those having excellent optical transparency, appropriate wettability, cohesiveness and adhesive properties, and excellent weather resistance and heat resistance are preferably used. As what shows these characteristics, an acrylic adhesive is used preferably.

As a method of forming the pressure-sensitive adhesive layer, for example, a method in which the pressure-sensitive adhesive is applied to a peeling-treated separator or the like and the polymerization solvent is dried to form the pressure-sensitive adhesive layer and then transferred to the flexible polarizing film, or the above-mentioned pressure-sensitive adhesive is applied to the flexible polarizing film It is produced by, for example, a method in which an adhesive layer is formed on a polarizer by coating and drying off a polymerization solvent or the like. In addition, in apply|coating an adhesive, you may newly add 1 or more types of solvents other than a polymerization solvent suitably.

The thickness in particular of an adhesive layer is not restrict|limited, For example, it is about 1-100 micrometers. Preferably it is 2-50 micrometers, More preferably, it is 2-40 micrometers, More preferably, it is 5-35 micrometers.

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a peeling-treated sheet (separator) until it is put to practical use.

<Surface protection film>

Moreover, a surface protection film can be provided in the flexible polarizing film of this invention. A surface protection film usually has a base film and an adhesive layer, and protects a flexible polarizing film through the said adhesive layer.

As the base film of the surface protection film, a film material having isotropy or close to isotropy is selected from the viewpoints of inspection properties, manageability, and the like. Examples of the film material include polyester-based resins such as polyethylene terephthalate film, cellulose-based resins, acetate-based resins, polyethersulfone-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, and polyolefin-based resins. and transparent polymers such as resins and acrylic resins. Among these, polyester-type resin is preferable. A base film may be used as a laminated body of 1 type(s) or 2 or more types of film materials, and also the stretched material of the said film may be used. The thickness of a base film is generally 500 micrometers or less, Preferably it is 10-200 micrometers.

As the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer of the surface protection film, an adhesive having a (meth)acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer as the base polymer can be appropriately selected and used. have. From the viewpoints of transparency, weather resistance, heat resistance, and the like, an acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer is preferable. The thickness of the pressure-sensitive adhesive layer (dry film thickness) is determined by the required adhesive force. Usually, it is about 1-100 micrometers, Preferably it is 5-50 micrometers.

In addition, a peeling process layer can be provided in the surface protection film with low adhesive material, such as silicone treatment, a long-chain alkyl treatment, and a fluorine treatment, on the surface opposite to the surface on which the adhesive layer in the base film was provided.

<Other optical layers>

The flexible polarizing film of the present invention is a substitute for a polarizer or a polarizing film (a transparent protective film is installed on the polarizer), and can expand the development of various uses that cannot be applied to conventional polarizers or polarizing films, for example, It can be used also as an optical film laminated|stacked with other optical layers. Although there is no restriction|limiting in particular about the optical layer, For example, when using the flexible polarizing film of this invention as a substitute for a polarizer, the protective film used for protection of a polarizer (including retardation film, a brightness improving film, a diffusion film, etc.) is used. In the case of using as a substitute for a polarizing film, a reflective plate, a transflective plate, a retardation film (including a wave plate such as 1/2 or 1/4), a visual compensation film, etc., a liquid crystal display device, an organic EL display device, etc. One or two or more optical layers may be used for forming an image display device of

<Intervening layer>

The optical layer and the flexible polarizing film may be laminated with an intervening layer such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer) interposed therebetween. At this time, it is preferable to laminate both without an air gap by an intervening layer.

The flexible polarizing film of the present invention or an optical film using the same can be suitably used for forming various image display devices such as a liquid crystal display device and an organic EL display device. The liquid crystal display may be formed according to a conventional method. That is, a liquid crystal display is generally formed by assembling a liquid crystal cell, a flexible polarizing film of the present invention or an optical film using the same, and, if necessary, components such as a lighting system, and embedding a driving circuit, etc. It is not particularly limited except for using a flexible polarizing film of the conventional method. Also about a liquid crystal cell, although arbitrary types, such as an IPS type|mold and a VA type, can be used, for example, it is especially preferable for an IPS type|mold.

[Example]

The present invention will be described below by way of examples, but the present invention is not limited to the examples shown below. In addition, any part and % in each example are based on weight. The room temperature leaving conditions not specifically limited to the following are all 23 degreeC and 65%RH.

<Production of polarizer (A0)>

Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption rate of 0.75% and Tg of 75 ° C. Corona treatment is performed on one side of the substrate, and polyvinyl alcohol (polymerization degree 4,200, saponification 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1,200, acetoacetyl modification 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Kosei Chemical Co., Ltd., trade name "Gosefaimer Z200") in a ratio of 9:1 A PVA-based resin layer having a thickness of 11 μm was formed by coating and drying an aqueous solution containing a PVA at 25° C. to prepare a laminate.

The obtained laminate was uniaxially stretched at the free end 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120°C (air-assisted stretching treatment).

Next, the laminate was immersed for 30 seconds in an insolubilization bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) having a liquid temperature of 30°C for 30 seconds (insolubilization treatment).

Then, it was immersed in the dyeing bath with a liquid temperature of 30 degreeC, adjusting iodine concentration and immersion time so that a polarizing plate might become predetermined transmittance|permeability. In this example, 0.2 parts by weight of iodine was blended with respect to 100 parts by weight of water, and 1.0 parts by weight of potassium iodide was mixed and immersed in an aqueous iodine solution obtained for 60 seconds (dyeing treatment).

Then, it was immersed for 30 seconds in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water) having a liquid temperature of 30°C for 30 seconds (crosslinking treatment).

Thereafter, while immersing the laminate in an aqueous boric acid solution having a liquid temperature of 70° C. (aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water and 5 parts by weight of potassium iodide), the stack was placed between rolls having different peripheral speeds. Uniaxial stretching was performed so that the total draw ratio in the direction (longitudinal direction) was 5.5 times (underwater stretching treatment)

Thereafter, the laminate was immersed in a washing bath (aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) having a liquid temperature of 30°C (washing treatment).

By the above, the optical film laminated body containing the polarizer with a thickness of 5 micrometers was obtained.

<Production of polarizers (A1-A2)>

Production of said polarizer A0 WHEREIN: Except having changed manufacturing conditions as shown in Table 1, it carried out similarly to preparation of polarizer A0, and produced polarizer A1-A2. Table 1 shows the thickness, optical properties (single transmittance, polarization degree), and boric acid concentration of the polarizers A0 to A2.

[Table 1]

<Production of polarizer (B1) (polarizer having a thickness of 12 µm)>

A polyvinyl alcohol film having an average degree of polymerization of 2,400 and a degree of saponification of 99.9 mol% and having a thickness of 30 µm was immersed in hot water at 30°C for 60 seconds to swell. Then, the film was immersed in an aqueous solution having a concentration of 0.3% of iodine/potassium iodide (weight ratio = 0.5/8), and the film was dyed while stretching to 3.5 times. Then, it extended|stretched so that the total draw ratio might be 6 times in 65 degreeC boric-acid ester aqueous solution. After extending|stretching, it dried in 40 degreeC oven for 3 minutes, and obtained the polarizer (B1). The thickness of the obtained polarizer (B1) was 12 micrometers. The optical characteristics of the obtained polarizer (B1) were 42.8% of transmittance|permeability and 99.99% of polarization degree.

<Production of polarizer B2 (polarizer with a thickness of 23 µm)>

A polyvinyl alcohol film having an average degree of polymerization of 2,400 and a degree of saponification of 99.9 mol% and having a thickness of 75 μm was immersed in hot water at 30° C. for 60 seconds to swell. Then, the film was dyed while being immersed in an aqueous solution having a concentration of 0.3% of iodine/potassium iodide (weight ratio = 0.5/8) and stretched to 3.5 times. Then, it extended|stretched so that the total draw ratio might be 6 times in 65 degreeC boric-acid ester aqueous solution. After extending|stretching, it dried in 40 degreeC oven for 3 minutes, and obtained the polarizer (B2). The thickness of the obtained polarizer (B2) was 23 micrometers. The optical characteristics of the obtained polarizer (B2) were 42.8% of transmittance|permeability and 99.99% of polarization degree.

<Material for forming reinforcing film>

(1) Polyurethane-based material

50 parts of polycarbonate polyol (Sumika Bayer Urethane Co., Ltd., Desmofen C3100XP) in 50 parts of urethane prepolymer (manufactured by Tosoh Corporation, Coronate L) consisting of tolylene isocyanate and trimethylolpropane, dioctyltin dilaurate catalyst (Tokyo) Fine Chemicals, Envirizer OL-1) 0.1 part was added, and the coating liquid adjusted to 35% of solid content concentration using methyl isobutyl ketone as a solvent was obtained.

(2) UV curing materials

A reaction product of a polymer comprising 2-hydroxyethyl acrylate and 1,6-diisocyanatohexane in 50 parts of urethane acrylate oligomer (manufactured by Nippon Kosei Chemicals, Magnolight UV1700TL) (manufactured by BASF, product name D) 50 parts of Rome LR9000) and 3 parts of a photoinitiator (manufactured by BASF, IRGACURE907) were added, and a coating solution adjusted to a solid content concentration of 35% using methyl isobutyl ketone as a solvent was obtained.

(3) Water-based resin emulsion material

Pure water was added as a solvent to an acrylic emulsion (trade name: SE-2915E manufactured by Taisei Fine Chemicals) to obtain a coating solution adjusted to a solid content concentration of 30%.

<Protective film (acrylic) and adhesive>

The easily-adhesive treatment surface of the (meth)acrylic resin film which has a lactone ring structure of 20 micrometers in thickness was corona-treated and used.

As an adhesive applied to the above protective film (acrylic), 40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO), and a photoinitiator "IRGACURE 819" (manufactured by BASF) 3 A weight part was mixed, and the ultraviolet curing adhesive agent was prepared.

Example 1 (production of flexible polarizing film)

The polyurethane-based material (1) of the reinforcing film was applied to the polarizer (first side) of the polarizer (A0) obtained above (optical film laminate including a polarizer having a thickness of 5 μm) using a wire bar coater to have a thickness of 5 After coating so that it may become micrometer, the 1st reinforcing film was formed by performing initial hardening under the conditions of 60 degreeC for 10 minutes, and then performing annealing treatment under the conditions of 60 degreeC and 12 hours. Next, after bonding a surface protection film (the Nitto Denko make, RP301) on the said 1st reinforcement film|membrane, the amorphous PET base material of the said optical film laminated body was peeled. After that, the polyurethane material (1) of the reinforcing film is coated on the polarizer (the second side, which is the peeling side) using a wire bar coater so that the thickness after curing becomes 5 μm, and then initial curing at 60° C. for 10 minutes. After that, a second reinforcing film was formed by further annealing at 60°C for 12 hours. Then, the flexible polarizing film which has a reinforcement film on both surfaces of a polarizer was obtained by peeling the surface protection film bonded on the 1st reinforcement film.

Examples 2 to 4

In Example 1, a flexible polarizing film having a reinforcing film on both surfaces of the polarizer was produced in the same manner as in Example 1 except that the type of polarizer and the thickness of the reinforcing film were changed as shown in Table 2.

Example 5 (production of flexible polarizing film)

The UV curing material (2) of the reinforcing film was applied to the polarizer (first side) of the polarizer (A0) obtained above (optical film laminate including a polarizer having a thickness of 5 μm) using a wire bar coater to determine the thickness after curing After coating so as to become 5 μm, it was heated at 60° C. for 1 minute. A first reinforcing film was formed by irradiating the coated film after heating with ultraviolet rays having an accumulated light amount of 300 mJ/cm ^{2 with a high-pressure mercury lamp.} Next, after bonding a surface protection film (manufactured by Nitto Denko, RP301) on the first reinforcing film, the amorphous PET substrate of the optical film laminate was peeled off. Then, the UV-curable material (2) of the reinforcing film was coated on the polarizer (the second side, which is the peeling side) using a wire bar coater so that the thickness after curing was 5 μm, and then heated at 60° C. for 1 minute. A second reinforcing film was formed by irradiating the coated film after heating with ultraviolet rays having an accumulated light amount of 300 mJ/cm 2 with a high-pressure mercury lamp. Then, the flexible polarizing film which has a reinforcement film on both surfaces of a polarizer was obtained by peeling off the surface protection film bonded to the 1st reinforcement film.

Example 6 (Production of flexible polarizing film)

The water-based resin emulsion material (3) of the reinforcing film was applied to the polarizer (first side) of the polarizer (A0) obtained above (optical film laminate including a polarizer having a thickness of 5 μm) using a wire bar coater to determine the thickness after curing. After coating so as to be 5 μm, the first reinforcing film was formed by curing at 80° C. for 5 minutes. Next, after bonding a surface protection film (manufactured by Nitto Denko, RP301) on the first reinforcing film, the amorphous PET substrate of the optical film laminate was peeled off. After that, the water-based resin emulsion material (3) of the reinforcing film is coated on the polarizer (the second side that is the peeling side) using a wire bar coater so that the thickness after curing becomes 5 μm, and then cured at 80° C. for 5 minutes. to form a second reinforcing film. Then, the flexible polarizing film which has a reinforcement film on both surfaces of a polarizer was obtained by peeling the surface protection film bonded on the 1st reinforcement film.

Comparative Examples 1 to 3

In Example 1, except having changed the kind of polarizer and the thickness of the reinforcement film as shown in Table 2, it carried out similarly to Example 1, and produced the polarizing film which has a reinforcement film on both surfaces of a polarizer.

Comparative example 4 (production of one-sidedly protective polarizing film)

The UV curable adhesive is applied to the polarizer (first side) of the polarizer (A0) obtained above (optical film laminate including a polarizer having a thickness of 5 μm) so that the thickness of the adhesive layer after curing is 1 μm, and the protective film After bonding (acrylic) together, the adhesive agent was hardened by irradiating an ultraviolet-ray as an active energy ray. Ultraviolet irradiation was performed using a gallium-enclosed metal halide lamp, irradiation device: Fusion UV Systems, Inc. Light HAMMER10 valve: V valve, peak illuminance: 1600 mW/cm2, cumulative irradiation amount 1000/mJ/cm2 (wavelength 380 to 440 nm). , UV illuminance was measured using the Sola-Check system manufactured by Solatell. Next, the amorphous PET base material of the optical film laminated body was peeled, and the side protection polarizing film was obtained.

Comparative Example 5

In Example 1, except not having provided the 1st reinforcement film, it carried out similarly to Example 1, and produced the flexible polarizing film which has a 2nd reinforcement film only on one side of a polarizer.

Comparative Example 6

In Example 1, except not having provided the 2nd reinforcement film, it carried out similarly to Example 1, and produced the flexible polarizing film which has a 1st reinforcement film only on one side of a polarizer.

Samples were prepared for the flexible polarizing film obtained in the above examples, the polarizing film having the reinforcing film obtained in the comparative example, and the single protective polarizing film, and the following evaluation was performed. A result is shown in Table 2. Moreover, in Comparative Examples 7-9, the single-piece|unit of polarizer A0, A1, B1 was evaluated. Light polarizer (A0, A1) with a thin film receded, and evaluation by a single body was impossible to measure other than rigidity. The evaluation was performed under conditions of 23° C. and 65% RH.

<Single transmittance (T) and degree of polarization (P) of the polarizer>

The single transmittance (T) and the degree of polarization (P) of the obtained polarizing film were measured using a spectral transmittance meter with an integrating sphere (Dot-3c of Murakami Color Technology Research Institute).

In addition, the degree of polarization (P) is the transmittance (parallel transmittance: Tp) when two identical polarizing films are superposed so that their transmission axes are parallel, and the transmittance (orthogonal transmittance: Tc) can be calculated|required by applying to the following formula|equation.

Polarization degree (P)(%)={(Tp-Tc)/(Tp+Tc)} ^1/2 × 100

Each transmittance is expressed as a Y value corrected for visibility by a 2 degree field of view (C light source) of JIS Z8701 with 100% of fully polarized light obtained through a Glan Taylor prism.

<Measurement of compressive modulus>

A TI900 TriboIndenter (manufactured by Hysitron) was used for the measurement of the compressive modulus. The obtained polarizer with a reinforcing film (polarizing film) was cut to a size of 10 mm × 10 mm and fixed to a support of the Tribolndenter device, and the compressive modulus was measured by the nanoindentation method. At this time, the position was adjusted so that the indenter used might press-in the vicinity of the center of the transparent layer. Measurement conditions are shown below.

Indenter used: Berkovich (triangular pyramid)

Measurement method: single indentation measurement

Measuring temperature: 23℃

Indentation depth setting: 100nm

<U-shaped stretch test>

It was carried out using a planar body no-load U-shaped expansion tester (product name: main body DLDM111LH and jig: planar body no-load U-shaped expansion test jig) manufactured by Yuasa System Instruments.

Both ends (x, y) (50 mm) of a rectangular object 1 (sample) of 50 mm (absorption axis direction) × 100 mm (transmission axis direction) are attached to the supports 21 and 22 of the tester with double-sided tape ( (not shown), stretching was performed so that one side (first side) of the rectangular object 1 was inwardly U-shaped under the following conditions, and the rectangular object was bent (first in the transmission axis direction). 1 side bending). The state of one process of U-shaped expansion and contraction is shown in FIG. In the U-shaped expansion and contraction, the bending R (bending radius) was set to be 0, and the rectangular object 1 (sample) was bent from a planar state until it came into contact in a folded state in two. In the bending, both ends (x, y) are contacted by the operation of the supporting part, and at the same time, the other parts of the rectangular object 1 (sample) are separately installed plate parts 23 and 24. ) to make contact by inserting it from both outside without load.

In addition, the bending by expansion and contraction was performed in the same manner as above for the other side (second side) of the rectangular object to become U-shaped inward (bending on the second side side in the transmission axis direction).

In addition, the bending by the expansion and contraction is performed in the same manner as above for a rectangular object (sample) of 50 mm (transmission axis direction) × 100 mm (absorption axis direction) so that the first side and the second side are inwardly U-shaped. (bending on the first surface side and the second surface side in the absorption axis direction).

Stretching speed: 30rpm

Bending (R): 0

Number of stretches: 100 times

The state of the U-shaped stretch test sample was visually evaluated on the basis of the following criteria.

(circle): No cracks or light leakage occurred in any of 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 bending in the absorption axis direction. Also, there were no fold marks left.

x: Cracks or light leakage occurred in any one of the bending of the first and second surfaces in the transmission axis direction and the bending of the first and second surfaces in the absorption axis direction. Or a crease was identified.

<Torsion (salting) test>

It was carried out using a planar body no-load torsion tester (product name: main body TCDM111LH and jig: planar body no-load torsion test jig) manufactured by Yuasa System Instruments.

After fixing both short sides of a rectangular object 1 (sample) of 100 mm (absorption axis direction) x 150 mm (transmission axis direction) with the twist clips 11 and 12 of the tester, one short side is clip (12) The clip 11 on the other short side side was twisted under the following conditions while being fixed with . The twisted state is shown in FIG. 3 .

Torsion speed: 10rpm

Twisting angle: 45 degrees

Twists: 100

The state of the sample after the torsion test was visually evaluated based on the following criteria.

(circle): Cracking and light leakage did not generate|occur|produce. Also, no crease marks remained.

(triangle|delta): Cracking and light leakage did not generate|occur|produce. But the crease remained.

x: Cracks and light leakage occurred. Also, a crease remained.

The criteria for cracks, folds and light leakage in the U-shaped stretch test and torsion test are as follows.

"Crack" indicates that the sample (the entire layer constituting the flexible polarizing film, the polarizing film having the reinforcing film, or the partial protective polarizing film or a part thereof) has penetrated and a tear or crack has occurred.

A "fold mark" is a visible mark remaining even after the load is removed by bending or a local load on the sample (the entire layer constituting the flexible polarizing film, the polarizing film having the reinforcing film, or the entire layer or a part of the single protective polarizing film). indicates that this has occurred.

"Light leakage" indicates that a tear or crack has occurred in the polarizer itself. To confirm light leakage, the sample after the test (a flexible polarizing film, a polarizing film having a reinforcing film, or the entire layer constituting the single-protected polarizing film) and other conventional polarizing films are bonded to both sides of the glass in a cross-nicol state, This was done by shining light.

<Bending holding test>

A rectangular object 1 (sample) of 200 mm (absorption axis direction) x 300 mm (transmission axis direction) was placed on a horizontal stand 31 . Next, the rectangular object 1 was folded in three in the transmission axis direction (long axis direction), a load 32 of 100 g was applied so that the load was applied to the entire uppermost portion, and left to stand for 5 minutes. The bending state is shown in FIG. The load 32 was then removed.

Further, the same operation (the sample was folded in three in the absorption axis direction (long axis direction)) was also performed for a rectangular object (sample) measuring 200 mm (transmission axis direction) x 300 mm (absorption axis direction).

After the bending maintenance test, it was visually checked whether the sample was maintained in a folded state in three, and at the same time, if the folded shape was maintained, the sample was returned to its original state (flat) and visually evaluated according to the following criteria. Evaluation was performed three times, respectively, on the samples of the long side in the transmission axis direction and the long side in the absorption axis direction.

○: In any of the samples, the three-folded shape was maintained, there was no crack, and the original state was maintained (there is retention property).

x: The shape folded into three was not maintained in either sample. Alternatively, although the three-fold shape was maintained, cracks occurred upon loading (no retainability).

In addition, the judgment of "crack" is the same as the said U-shaped stretch test and the torsion test.

<Strength test>

No. of the Yasuda Seiki Seisakusho production. A cantilever-type flexibility tester of 476 was used. In addition, in this test, in order to exclude the influence of static electricity, the sample used for a test, etc. were appropriately neutralized and performed.

A rectangular object 1 (sample) of 50 mm (absorption axis direction) × 150 mm (transmission axis direction) has a flat top (50 mm × 150 mm: the same size as the sample) and a 45° slope at one end of the long side. , was installed so as to be located on the front side of the smooth SUS plate 41 having a trapezoidal cross section (see FIG. 5 ). The sample was installed so that there was an inclined surface in the direction of the transmission axis.

The sample was moved by gently sliding it toward the inclined surface at an extrusion speed of 10 mm/sec (1). The sample stopped moving at the point where the tip of the sample first came into contact with the inclined surface (2). The government measured the distance (L) (mm) the sample moved on the plane.

For a rectangular object 1 (a sample of a flexible polarizing film) of 50 mm (transmission axis direction) x 150 mm (absorption axis direction), the same operation as above (provided that the sample is installed so that there is an inclined surface in the absorption axis direction) was performed. .

The stiffness (mm) was 3 for the two patterns when the first side was the upper side and the second side was the upper side, respectively, for the samples of the long side in the transmission axis direction and the long side in the absorption axis direction. Each time, the shortest linear distance (L) (mm) was measured (a total of 12 samples), and it was set as the arithmetic mean of them.

In addition, in one or more measurements of any one of the 12 samples, when there is a sample that cannot be measured due to deformation or curl of the sample, it is determined that the sample is not measurable.

<Tensile Test>

A sample (a sample of a flexible polarizing film) was prepared by cutting into a predetermined shape of 10 mm (absorption axis direction) x 150 mm (transmission axis direction) with a multi-purpose specimen cutter (dumbbell).

The sample was subjected to a tensile test at a tensile rate of 50 mm/min using Autograph AG-IS manufactured by Shimadzu Corporation.

The sample was performed while fixing both sides in the transmission axis direction with clamps 51 and 52 (the distance 53 between the initial clamps was 50 mm), and pulling one side of the clamp 52 (see FIG. 6 ). ). The point at which the sample started to break or plastically deform was evaluated as "tensile strength".

The tensile strength was taken as the arithmetic average of the results of three measurements.

[Table 2]

1 Flexible Polarizing Film
a transparent protective film
b1 first reinforcing film
b2 second reinforcement film

Claims (17)

A polyvinyl alcohol-based polarizer having a thickness of 10 μm or less, in which a polyvinyl alcohol-based resin is oriented in one direction, and an iodine or a dichroic dye is adsorbed and oriented to the polyvinyl alcohol-based resin; After conducting a U-shaped stretching test in which the polyvinyl alcohol-based resin repeats stretching and contracting in a U-shape in the direction orthogonal to the orientation direction and the orientation direction, cracks, folds, and light leakage in any direction ) is absent,
Having a reinforcing film in close contact with the polyvinyl alcohol-based polarizer on both sides of the polyvinyl alcohol-based polarizer,
The reinforcing film is a flexible polarizing film, characterized in that the compressive elastic modulus at 23 °C is 1 MPa or more to 1 GPa or less. According to claim 1,
A flexible polarizing film characterized in that there are no cracks, folds, and light leakage after performing a twist (salting) test in the direction in which the polyvinyl alcohol-based resin is oriented. According to claim 1,
After performing a bending maintenance test in which the polyvinyl alcohol-based resin is oriented and bent and held in a direction perpendicular to the orientation direction, the bent shape is maintained in any direction and cracks do not occur A flexible polarizing film. According to claim 1,
A flexible polarizing film, characterized in that the stiffness (mm) is 60 mm or less in an orientation direction in which the polyvinyl alcohol-based resin is oriented and a stiffness test in a direction orthogonal to the orientation direction. According to claim 1,
In the tensile test, the flexible polarizing film, characterized in that the tensile strength in a direction orthogonal to the orientation direction in which the polyvinyl alcohol-based resin is oriented is 5 N/10 mm or more. According to claim 1,
The polyvinyl alcohol-based polarizer has an optical property represented by a single transmittance (T) and a polarization degree (P) by the following formula
P>-(10 ^0.929T-42.4 -1)×100 (however, T<42.3), or
A flexible polarizing film, characterized in that it is configured to satisfy the condition of P≥99.9 (however, T≥42.3). delete According to claim 1,
A flexible polarizing film, characterized in that at least one side of the reinforcing film has a thickness of 15 μm or less. 9. The method of claim 8,
A flexible polarizing film having a first reinforcing film having a thickness of 15 μm or less on a first surface 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 polyvinyl alcohol-based polarizer. 10. The method of claim 9,
The flexible polarizing film, characterized in that the difference between the thickness of the first reinforcing film and the second reinforcing film is 0 to 10 μm or less. According to claim 1,
The ratio of the thickness of the reinforcing film to the thickness of the polyvinyl alcohol-based polarizer is 0.4 or more and 2.0 or less. delete According to claim 1,
The flexible polarizing film, characterized in that the reinforcing film is not substantially oriented. According to claim 1,
The flexible polarizing film, characterized in that the reinforcing film is a resin film. 15. The method of claim 14,
The resin film is a flexible polarizing film, characterized in that it is formed of a thermosetting resin or an active energy ray-curable resin. A method for manufacturing the flexible polarizing film according to claim 14 or 15, comprising:
A step (1) of preparing a polyvinyl alcohol-based polarizer having a thickness of 10 μm or less, in which the polyvinyl alcohol-based resin is oriented in one direction and iodine or a dichroic dye is adsorbed and oriented to the polyvinyl alcohol-based resin;
A step (2) of forming a reinforcing film by coating a liquid material containing a resin component or a curable component capable of constituting a resin film on both sides of the polyvinyl alcohol-based polarizer, and then solidifying or curing the liquid material. Method of manufacturing a flexible polarizing film, characterized in that. The image display apparatus which has a flexible polarizing film in any one of Claims 1-6, 8-11, and 13-15.

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