WO2016052538A1

WO2016052538A1 - Method for producing polarizing film

Info

Publication number: WO2016052538A1
Application number: PCT/JP2015/077578
Authority: WO
Inventors: 恵美中岡; 健太郎池嶋; 俊樹大峰; 聡司三田; 岸　敦史; 友徳上野
Original assignee: 日東電工株式会社
Priority date: 2014-09-30
Filing date: 2015-09-29
Publication date: 2016-04-07

Abstract

This method for producing a polarizing film comprises: a step (1) for preparing a laminate (a) which comprises a film for conveyance and a polarizer that is formed on one surface of the film for conveyance and contains a polyvinyl alcohol resin, while having a thickness of 10 μm or less; a step (2) for removing the film for conveyance from the laminate (a); and a step (3) for forming a transparent resin layer having a thickness of 0.2 μm or more by applying a liquid material that contains a resin component or a curable component which is capable of constituting a resin layer to a surface of the laminate (a), from which the film for conveyance is removed, and subsequently solidifying or curing the liquid material. This production method enables the achievement of a polarizing film which is able to have satisfactory durability in a heated environment even in cases where a thin polarizer is used therefor.

Description

Manufacturing method of polarizing film

The present invention relates to a method for producing a polarizing film. The polarizing film can be used as a polarizing film in which a protective film is provided on at least one surface of a polarizer. Further, the polarizing film may be further provided with an adhesive layer and used as a polarizing film with an adhesive layer. The polarizing film can form an image display device such as a liquid crystal display device (LCD) or an organic EL display device alone or as an optical film obtained by laminating the polarizing film.

Liquid crystal display devices are rapidly expanding in the market for watches, mobile phones, PDAs, notebook computers, personal computer monitors, DVD players, TVs, etc. The liquid crystal display device visualizes the polarization state by switching of the liquid crystal, and a polarizer is used from the display principle.

As the polarizer, since it has a high transmittance and a high degree of polarization, for example, an iodine-based polarizer having a structure in which iodine is adsorbed on polyvinyl alcohol and stretched is most widely used. Such a polarizer has a disadvantage that the mechanical strength is extremely weak, and the polarizing function is remarkably lowered due to contraction due to heat and moisture. Therefore, the obtained polarizer is immediately bonded to the protective film coated with the adhesive via the adhesive and used as a polarizing film.

On the other hand, image display devices such as liquid crystal display devices are becoming thinner, and the polarizing film is also required to be thinner. When a thin polarizer is manufactured, the polarizer is damaged due to the thin polarizer. Therefore, a transport (peelable protective film) film is used for manufacturing a thin polarizer. For example, a thin polarizer can be obtained on the transport film by stretching and dyeing a laminate having a transport film and a polyvinyl alcohol-based resin layer formed on one side of the transport film ( Patent Documents 1 to 6). Moreover, the protective film can be used only on one side of the polarizer and the protective film can be used on the other side without the protective film. The single-protective polarizing film can be a thin type because the protective film is less than one protective polarizing film provided with protective films on both sides of the polarizer.

JP 2000-338329 A JP 2001-343521 A JP 2011-227450 A JP 2013-033084 A International Publication No. 2014/077599 Pamphlet International Publication No. 2014/077636 Pamphlet

Liquid crystal display devices are required to have durability capable of maintaining optical characteristics even under severe conditions at high temperatures. The durability is also required for a polarizing film using the above thin polarizer.

When the thin polarizer obtained by the production method described in Patent Documents 1 to 6 is put to practical use, the transport film is usually peeled off. Moreover, when producing a piece protection polarizing film using the said thin polarizer, a protective film is laminated | stacked through an adhesive agent on a polarizer, for example, Then, a film for conveyance is peeled from a polarizer. Thus, a piece protective polarizing film is produced. For example, a pressure-sensitive adhesive layer is laminated on the polarizer side of the single protective polarizing film.

However, in the above manufacturing method, when the transport film is peeled off from the polarizer, a part of the surface of the polarizer is removed together with the transport film, or the polarizer is broken by the impact of peeling the transport film. Thus, it was found that when the polarizer was damaged (defective appearance) and was placed in a heating environment, the damage became obvious and was visually recognized as a defect of light leakage. In particular, in the above-mentioned piece protective polarizing film using the thin polarizer obtained by the production methods described in Patent Documents 1 to 6, since the protective film is not provided on the transport film side, When placed in an environment, the problem of the occurrence of light leakage at the damaged portion is likely to occur. Therefore, in the thin polarizer obtained by the said manufacturing method, and the piece protection polarizing film using the said thin polarizer, what satisfy | filled the said durability was not obtained.

An object of the present invention is to provide a method for producing a polarizing film using a thin polarizer that can satisfy durability even in a heating environment.

As a result of intensive studies, the present inventors have found that the above-described problems can be solved by the following method for producing a polarizing film, and have reached the present invention.

That is, the present invention provides a laminate (a) having a transport film and a polarizer (a) having a thickness of 10 μm or less containing a polyvinyl alcohol-based resin formed on one side of the transport film (1),
Step (2) of peeling the film for conveyance from the laminate (a), and curable resin layer or resin layer on the side of the laminate (a) from which the film for conveyance is peeled off. A polarizing film comprising a step (3) of forming a transparent resin layer having a thickness of 0.2 μm or more by applying a liquid material containing a component and then solidifying or curing the liquid material Manufacturing method.

In the method for producing a polarizing film, the transparent resin layer preferably has a compression elastic modulus at 80 ° C. of 0.1 GPa or more.

In the method for producing a polarizing film, the transparent resin layer formed in the step (3) can be formed by applying a liquid material containing a resin component dissolved or dispersed in water and then solidifying.

In the method for producing a polarizing film, the liquid material containing the resin component is preferably an aqueous solution containing a polyvinyl alcohol resin.

In the method for producing a polarizing film, the liquid material preferably has a viscosity at 25 ° C. of 1000 mPa · s or less.

In the manufacturing method of the polarizing film, the laminate (a) in the step (1) is a laminate (a ′) having a transport film and a polyvinyl alcohol-based resin layer formed on one surface of the transport film. Those obtained by performing at least a stretching step and a dyeing step can be used.

In the manufacturing method of the said polarizing film, it can have the process (4) which forms a protective film in the polarizer side of the said laminated body (a), and a protective film is provided only as one side of a polarizer as the said polarizing film. The piece protection polarizing film which has can be manufactured.

In the method for producing a polarizing film, the polarizer has an optical property represented by the following formula: P> − (10 ^0.929T-42.4 −1) × 100 , T <42.3), or
It is preferably in the range represented by P ≧ 99.9 (where T ≧ 42.3).

In the manufacturing method of the said polarizing film, it can have the process (5) which forms an adhesive layer further on the transparent resin layer side formed at the said process (3), and a polarizing film with an adhesive layer is provided. Can be manufactured.

In the manufacturing method of the polarizing film of this invention, after peeling a film for conveyance from the laminated body (a) which has a film for conveyance and the polarizer of thickness 10 micrometers or less formed in the single side | surface of the said film for conveyance, the said polarizer A transparent resin layer having a thickness of 0.2 μm or more is formed on the surface. Such a transparent resin layer can repair the damage generated on the surface of the thin polarizer and can eliminate the appearance defect related to the polarizer.

Moreover, since the polarizing film obtained by the production method of the present invention is provided with a transparent resin layer on the surface of the polarizer, it is possible to suppress the expansion of damage caused to the polarizer even under heating conditions. Thus, the polarizing film obtained by the production method of the present invention can suppress light leakage due to the damage even when the polarizing film is placed in a heating environment, and can satisfy durability. .

In the production method of the present invention, a transparent resin layer provided on a thin polarizer having a compression elastic modulus at 80 ° C. of 0.1 GPa or more is effective from the viewpoint of durability. The transparent resin layer (with a compressive modulus at 80 ° C. of 0.1 GPa or more) is preferable for suppressing defects due to damage caused in the polarizer while satisfying the reduction in thickness and in a heating environment. .

It is a conceptual diagram which shows an example of embodiment which concerns on the manufacturing method of the polarizing film of this invention. It is a photograph which shows sectional drawing before and behind heat processing about the piece protection polarizing film before forming a transparent resin layer at a process (3). It is a photograph which shows sectional drawing before and behind heat processing about the piece protection polarizing film with a transparent resin layer after forming a transparent resin layer at a process (3).

Hereinafter, steps (1) to (5) of the method for producing a polarizing film of the present invention will be described with reference to FIG. In the method for producing a polarizing film of the present invention, the steps (2) to (3) are sequentially performed after the step (1) of preparing the laminate (a) having the thin polarizer 1 and the transport film 3. Is done. The laminate (a) is likely to break during transportation. Therefore, as shown in FIG. 1, before performing the step (2) on the laminate (a), the protective film 2 is applied to the laminate 1 (a) on the polarizer 1 side by the step (4). It is preferable to provide and manufacture a piece protective polarizing film A ′ with a transport film. In FIG. 1, after the step (4), the step (2) is followed by the step (2) after the transport film 3 is peeled from the piece protective polarizing film A ′ with the transport film to produce the piece protective polarizing film A. ) To produce a piece protective polarizing film B with a transparent resin layer. A single protective polarizing film B with a transparent resin layer shown in FIG. 1 has a protective film 2 only on one side of a polarizer 1, and a transparent resin layer 4 is (directly) laminated on the other side of the polarizer 1. Has been.

Moreover, as shown in FIG. 1, the adhesive layer 5 is provided in the transparent resin layer 4 of the piece protection polarizing film B with a transparent resin layer by a process (5), and the polarizing film C with an adhesive layer is manufactured. be able to. In the step (5), the pressure-sensitive adhesive layer 5 can be provided on the transparent resin layer 4 side and / or the protective film 2 side of the piece protective polarizing film B with a transparent resin layer. In addition, in FIG. 1, the case where the adhesive layer 5 is provided in the transparent resin layer 4 side of the piece protection polarizing film B with a transparent resin layer is illustrated as a process (5).

FIG. 2A is a photograph of a cross-sectional view of the piece protective polarizing film A before forming the transparent resin layer 4 in the step (3) according to the prior art. In A1 of FIG. 2A, it turns out that the damage d has arisen in the polarizer 1 as a result of peeling the film 3 for conveyance in a process (2). Moreover, A2 of FIG. 2 shows the photograph of sectional drawing when the said piece protection polarizing film A is put in a heating environment. In A2 of FIG. 2A, it turns out that the damage d of the polarizer 1 is expanded by heating.

FIG. 2B is a photograph of a cross-sectional view of a piece protective polarizing film B with a transparent resin layer in which the transparent resin layer 4 is formed in the step (3) according to the present invention. In B <b> 1 of FIG. 2B, it can be seen that damage d generated in the polarizer 1 is repaired (d ′) by the transparent resin layer 4 as a result of peeling the transport film 3 in the step (2). Moreover, B2 of FIG. 2 shows the photograph of sectional drawing at the time of heat-processing the piece protection polarizing film B with the said transparent resin layer. In B2 of FIG. 2B, it can be seen that the damage d of the polarizer 1 is not enlarged even by the heat treatment and is sufficiently repaired (d ′).

<Process (1)>
In the step (1), a laminate (a) having a transport film 3 and a polarizer 1 having a thickness of 10 μm or less formed on one surface of the transport film 3 is prepared. In addition, the said laminated body (a) should just have the polarizer 1 with a thickness of 10 micrometers or less on the at least single side | surface of the film 3 for conveyance, The said laminated body (a) is a polarizer on both surfaces of the film 3 for conveyance. 1 can be included.

≪Laminated body (a) ≫
The laminate (a) includes, for example, at least a laminate (a ′) having a transport film and a polyvinyl alcohol resin (hereinafter also referred to as PVA resin) layer formed on one surface of the transport film. It is obtained by performing a stretching process and a dyeing process. The transport film can form a long PVA-based resin layer by using a long material, which is advantageous for continuous production.

<< Conveyor film >>
Various thermoplastic resin films can be used as the transport film. Examples of the material for forming the thermoplastic resin film include ester resins such as polyethylene terephthalate resins, cycloolefin resins such as norbornene resins, olefin resins such as polyethylene and polypropylene, polyamide rheo resins, polycarbonate resins, and the like. And a copolymer resin. Of these, ester resins are preferred from the viewpoint of ease of production and cost reduction. As the ester-based thermoplastic resin film, an amorphous ester-based thermoplastic resin film or a crystalline ester-based thermoplastic resin film can be used. The thickness of the thermoplastic resin film is preferably thicker from the viewpoint of avoiding breakage in the stretching step and easy transport of the laminate (a). Usually, the thickness before the stretching step is 20 to 200 μm. More preferably, it is 30 to 150 μm.

Further, as the transport film, a film provided with a peelable adhesive layer on the thermoplastic resin film can be used. As an adhesive layer, the thing similar to what is used for the peelable surface protection film etc. can be used.

≪Thin polarizer≫
The polarizer in the laminate (a) contains a polyvinyl alcohol resin and has a thickness of 10 μm or less. The thickness of the polarizer is preferably 8 μm or less from the viewpoint of thinning, more preferably 7 μm or less, and further preferably 6 μm or less. On the other hand, the thickness of the polarizer is preferably 2 μm or more, and more preferably 3 μm or more. Such a thin polarizer is liable to be damaged when the transport film is peeled from the laminate (a) in the step (2). On the other hand, a thin polarizer has little thickness unevenness, excellent visibility, and is excellent in durability against thermal shock because of little dimensional change.

The polarizer preferably contains boric acid from the viewpoint of stretching stability and optical durability. In addition, the boric acid content in the polarizer is the total amount of the polarizer from the viewpoint of suppressing the occurrence of cracks in the heat cycle test (repetition of −40 ° C. and 80 ° C.) and the damage to the polarizer that occurs when the film for transportation is peeled off. The amount is preferably 25% by weight or less, more preferably 20% by weight or less, further 18% by weight or less, and further preferably 16% by weight or less. When the content of boric acid contained in the polarizer exceeds 20% by weight, even if the thickness of the polarizer is controlled to 10 μm or less, the contraction stress of the polarizer increases and cracks are likely to occur, which is not preferable. . On the other hand, from the viewpoint of the stretching stability and optical durability of the polarizer, the boric acid content with respect to the total amount of the polarizer is preferably 10% by weight or more, and more preferably 12% by weight or more.

As a thin polarizer, typically,
Patent No. 4751486,
Japanese Patent No. 4751481,
Patent No. 4815544,
Patent No. 5048120,
International Publication No. 2014/077599 pamphlet,
International Publication No. 2014/077636 Pamphlet,
And the thin polarizers obtained from the production methods described therein.

The polarizer has an optical characteristic expressed by a single transmittance T and a polarization degree P of the following formula P> − (10 ^0.929T-42.4 −1) × 100 (where T <42.3), Or
It is preferably configured to satisfy the condition of P ≧ 99.9 (however, T ≧ 42.3). A polarizer configured so as to satisfy the above-described conditions uniquely has performance required as a display for a liquid crystal television using a large display element. Specifically, the contrast ratio is 1000: 1 or more and the maximum luminance is 500 cd / m ² or more. As other uses, for example, it is bonded to the viewing side of the organic EL display device.

On the other hand, a polarizer containing a polyvinyl alcohol-based resin configured to satisfy the above conditions is combined with a thickness of 10 μm or less because the polyvinyl alcohol-based molecule exhibits high orientation, The tensile breaking stress in the direction orthogonal to the absorption axis direction is significantly reduced. As a result, in the step (2), when the transport film is peeled from the piece-protecting polarizing film with a transport film, the surface of the polarizer is easily damaged. Therefore, this invention is especially suitable for the piece protection polarizing film which employ | adopted the said polarizer.

As the thin-type polarizer, among the production methods including a stretching step and a dyeing step in the state of the laminate (a ′), it can be stretched at a high magnification and can improve polarization performance. Patent Nos. 4,751,481 and 4,815,544, and those obtained by a production method including a step of stretching in an aqueous boric acid solution are preferable, and particularly, patents 4,751,481, and 4,815,544. What is obtained by the manufacturing method including the process of extending | stretching in the air auxiliary | assistant before extending | stretching in the boric-acid aqueous solution described in (5) is preferable. These thin polarizers can be obtained by a production method including a step of stretching and dyeing a polyvinyl alcohol-based resin (hereinafter also referred to as PVA-based resin) layer and a film for stretching in the state of a laminate. If it is this manufacturing method, even if a PVA-type resin layer is thin, it will be possible to extend | stretch without troubles, such as a fracture | rupture by extending | stretching, by being supported by the film for conveyance for extending | stretching.

The laminate (a ′) can be formed, for example, by applying an aqueous solution of PVA-based resin to a transport film and then drying. Moreover, the PVA-type resin layer in the said laminated body (a ') can be formed on a film for conveyance by extrusion molding. Furthermore, the PVA-based resin layer can be formed by laminating a PVA-based resin film prepared in advance on a transport film. The thickness of the PVA-based resin layer is appropriately determined in consideration of the draw ratio and the like so that the thickness of the polarizer obtained after stretching is 10 μm or less. In addition, if the PVA-type resin film is dyed, the dyeing process performed to a laminated body (a ') can be skipped.

The stretching step applied to the laminate (a ′) is preferably performed, for example, so that the total stretching ratio of the PVA-based resin layer is in the range of 3 to 10 times in terms of the total stretching ratio. The total draw ratio is preferably 4 to 8 times, more preferably 5 to 7 times. The total draw ratio is desirably 5 times or more. The stretching process can also be performed in the dyeing process and other processes. The total stretching ratio refers to a cumulative stretching ratio including stretching in those processes when stretching is performed in a process other than the stretching process.

The dyeing process applied to the laminate (a ′) is performed by adsorbing and orienting a dichroic dye or iodine to the PVA resin layer. The dyeing process can be performed together with the stretching process. A dyeing process is generally performed, for example, by immersing in the laminate (a ′) iodine solution for an arbitrary time. As the iodine aqueous solution used as the iodine solution, an aqueous solution containing iodine ions with iodine and an iodide compound which is a dissolution aid is used. Examples of the iodide compound include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide. Etc. are used. As the iodide compound, potassium iodide is preferred. The iodide compound used in the present invention is the same as described above when used in other steps.

The iodine concentration in the iodine solution is about 0.01 to 10% by weight, preferably 0.02 to 5% by weight, and more preferably 0.02 to 0.5% by weight. The iodide compound concentration is preferably about 0.1 to 10% by weight, more preferably 0.2 to 8% by weight. In iodine staining, the temperature of the iodine solution is usually about 20 to 50 ° C., preferably 25 to 40 ° C. The immersion time is usually about 10 to 300 seconds, preferably 20 to 240 seconds.

The laminate (a ′) can be subjected to, for example, an insolubilization step, a crosslinking step, a drying (adjustment of moisture content) step, and the like in addition to the above steps.

In the insolubilization step and the crosslinking step, a boron compound is used as a crosslinking agent. The order of these steps is not particularly limited. The crosslinking step can be performed together with the dyeing step and the stretching step. The insolubilization step and the crosslinking step can be performed a plurality of times. Examples of the boron compound include boric acid and borax. The boron compound is generally used in the form of an aqueous solution or a water-organic solvent mixed solution. Usually, an aqueous boric acid solution is used. The boric acid concentration in the boric acid aqueous solution is about 1 to 10% by weight, preferably 2 to 7% by weight. In order to impart heat resistance depending on the degree of crosslinking, or to suppress damage during peeling of the transport film, the boric acid concentration is preferably used. The boric acid aqueous solution or the like can contain an iodide compound such as potassium iodide. When the iodide compound is contained in the boric acid aqueous solution, the iodide compound concentration is preferably about 0.1 to 10% by weight, more preferably 0.5 to 8% by weight.

<Process (4)>
As mentioned above, before performing a process (2), it is preferable to perform the process (4) which forms the protective film 2 in the polarizer 1 side of the said laminated body (a). By the said process (4), the piece protection polarizing film A 'with the film for conveyance which has the protection film 2 only on the one side of the polarizer 1 is obtained.

≪Protective film≫
As the material constituting the protective film, a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) And polymers based on polycarbonate and polycarbonate. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like can also be mentioned as examples of the polymer forming the protective film. These protective films are usually bonded to the polarizer by an adhesive layer.

In addition, 1 or more types of arbitrary appropriate additives may be contained in the protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the protective film is preferably 50 to 100% by mass, more preferably 50 to 99% by mass, still more preferably 60 to 98% by mass, and particularly preferably 70 to 97% by mass. When content of the said thermoplastic resin in a protective film is 50 mass% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has cannot fully be expressed.

As the protective film, a retardation film, a brightness enhancement film, a diffusion film, and the like can also be used. Examples of the retardation film include those having a front retardation of 40 nm or more and / or a retardation having a thickness direction retardation of 80 nm or more. The front phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. In the case where a retardation film is used as the protective film, the retardation film functions also as a polarizer protective film, so that the thickness can be reduced.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film. The stretching temperature, stretching ratio, and the like are appropriately set depending on the retardation value, film material, and thickness.

The thickness of the protective film can be determined as appropriate, but in general, it is preferably 3 to 200 μm, more preferably 3 to 100 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. Is preferred. In particular, the thickness of the protective film (when a film is formed in advance) is preferably 10 to 60 μm, more preferably 10 to 45 μm from the viewpoint of transportability. On the other hand, the thickness of the protective film (when formed by coating and curing) is preferably 3 to 25 μm, more preferably 3 to 20 μm from the viewpoint of transportability. The protective film may be used in a plurality of layers or in a plurality of layers.

A functional layer such as a hard coat layer, an antireflection layer, an antisticking layer, a diffusion layer or an antiglare layer can be provided on the surface of the protective film to which the polarizer is not adhered. In addition, the hard coat layer, the antireflection layer, the antisticking layer, the diffusion layer, the antiglare layer, and other functional layers can be provided on the protective film itself, or can be provided separately from the protective film. it can.

<Intervening layer>
The said protective film and polarizer can be laminated | stacked through intervening layers, such as an adhesive bond layer, an adhesive layer, and undercoat (primer layer). At this time, it is desirable that the both are laminated without an air gap by an intervening layer. In addition, the intervening layer of the polarizer 1 and the protective film 2 is not shown in FIG.

The adhesive layer is formed with an adhesive. The type of the adhesive is not particularly limited, and various types can be used. The adhesive layer is not particularly limited as long as it is optically transparent. Examples of the adhesive include water-based, solvent-based, hot-melt-based, active energy ray-curable types, and the like. Or an active energy ray hardening-type adhesive agent is suitable.

Examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex systems, and water-based polyesters. The water-based adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of solid content.

The active energy ray curable adhesive is an adhesive that cures by an active energy ray such as an electron beam or ultraviolet rays (radical curable type, cationic curable type), for example, in an electron beam curable type or an ultraviolet curable type. Can be used. As the active energy ray curable adhesive, for example, a photo radical curable adhesive can be used. When the photo radical curable active energy ray curable adhesive is used as an ultraviolet curable adhesive, the adhesive contains a radical polymerizable compound and a photo polymerization initiator.

The adhesive coating method is appropriately selected depending on the viscosity of the adhesive and the target thickness. Examples of coating methods include reverse coaters, gravure coaters (direct, reverse and offset), bar reverse coaters, roll coaters, die coaters, bar coaters, rod coaters and the like. In addition, for coating, a method such as a dapping method can be appropriately used.

In addition, when the water-based adhesive or the like is used, the adhesive is preferably applied so that the finally formed adhesive layer has a thickness of 30 to 300 nm. The thickness of the adhesive layer is more preferably 60 to 150 nm. On the other hand, when an active energy ray curable adhesive is used, the thickness of the adhesive layer is preferably 0.2 to 20 μm.

In addition, in laminating | stacking a polarizer and a protective film, an easily bonding layer can be provided between a protective film and an adhesive bond layer. The easy adhesion layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins can be used alone or in combination of two or more. Moreover, you may add another additive for formation of an easily bonding layer. Specifically, a stabilizer such as a tackifier, an ultraviolet absorber, an antioxidant, and a heat resistance stabilizer may be used.

The easy-adhesion layer is usually provided in advance on a protective film, and the easy-adhesion layer side of the protective film and the polarizer are laminated with an adhesive layer. The easy-adhesion layer is formed by applying and drying a material for forming the easy-adhesion layer on a protective film by a known technique. The material for forming the easy-adhesion layer is usually adjusted as a solution diluted to an appropriate concentration in consideration of the thickness after drying and the smoothness of coating. The thickness of the easy-adhesion layer after drying is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and still more preferably 0.05 to 1 μm. Note that a plurality of easy-adhesion layers can be provided, but also in this case, the total thickness of the easy-adhesion layers is preferably in the above range.

The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive. Various pressure-sensitive adhesives can be used as the pressure-sensitive adhesive, such as rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives, polyvinylpyrrolidone-based pressure-sensitive adhesives, Examples include acrylamide-based adhesives and cellulose-based adhesives. An adhesive base polymer is selected according to the type of the adhesive. Among the pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and are excellent in weather resistance and heat resistance. The

The undercoat layer (primer layer) is formed to improve the adhesion between the polarizer and the protective film. The material constituting the primer layer is not particularly limited as long as the material exhibits a certain degree of strong adhesion to both the base film and the polyvinyl alcohol-based resin layer. For example, a thermoplastic resin excellent in transparency, thermal stability, stretchability, etc. is used. Examples of the thermoplastic resin include an acrylic resin, a polyolefin resin, a polyester resin, a polyvinyl alcohol resin, or a mixture thereof.

<Step (2)>
At a process (2), the said film 3 for conveyance is peeled from the said laminated body (a) or the piece protection polarizing film A 'with a film for conveyance. There is no restriction | limiting in particular in the peeling method of the film 3 for conveyance. When peeling the transport film 3, an angle may be given to the polarizer 1 (or the piece protective polarizing film A) side, or an angle may be given to the transport film 3 side. Moreover, you may peel at an angle on both sides. In any case, the thin polarizer 1 is likely to be damaged by the peeling of the transport film 3. The angle at which the transport film 3 is peeled is arbitrarily set. When the transport film 3 is peeled, there is an angle at which the peel force is weakest. The angle at which the peeling force becomes weak depends on the configuration, the peeling speed, the humidity at the time of peeling, and the rigidity of the film to be peeled, and can be determined as appropriate.

<Step (3)>
In a process (3), the transparent resin layer 4 is formed in the said polarizer 1 side in which the said film 3 for conveyance was peeled in the said process (2), and a polarizing film is manufactured. In FIG. 1, in the piece protection polarizing film A in which the protective film 2 is provided only on one side of the polarizer 1, the other side of the polarizer 1 of the piece protection polarizing film A (the surface on which the protection film 2 is not laminated). The case where the transparent resin layer 4 is provided is illustrated.

≪Transparent resin layer≫
In the present invention, the transparent resin layer preferably has a compression elastic modulus at 80 ° C. of 0.1 GPa or more. Damage to the polarizer can be controlled by controlling the compressive elastic modulus of the transparent resin layer at 80 ° C. to 0.1 GPa or more, thereby suppressing the expansion of defects due to damage generated in the polarizer even under heating conditions. . The compression elastic modulus of the transparent resin layer is preferably 0.5 GPa or more, further 3 GPa or more, more preferably 5 GPa or more, and further preferably 8 GPa or more. The compression elastic modulus of the transparent resin layer can be adjusted by material selection. In addition, the compression elastic modulus in 80 degreeC of a transparent resin layer is a value measured based on description of an Example.

The transparent resin layer is provided so as to have a thickness of 0.2 μm or more from the viewpoint of suppressing expansion of a damaged portion. The thickness is preferably 0.5 μm or more, and more preferably 0.7 μm or more. On the other hand, from the viewpoint of optical reliability, the thickness of the transparent resin layer is preferably 5 μm or less, preferably 3 μm or less, more preferably less than 3 μm, and even more preferably 2 μm or less. .

Examples of the material for forming the transparent resin layer include polyester resins, polyether resins, polycarbonate resins, polyurethane resins, silicone resins, polyamide resins, polyimide resins, PVA resins, acrylic resins, and epoxy resins. Based resins and the like. These resin materials can be used singly or in combination of two or more, and among these, one or more selected from the group consisting of polyurethane resins, PVA resins, acrylic resins, and epoxy resins Are preferable, and PVA resin and acrylic resin are more preferable.

The transparent resin layer is coated on the surface of the polarizer (the surface from which the transport film has been peeled) with a liquid material containing a curable component that can constitute the resin component or resin, It can be formed by solidifying or curing the liquid. The form of the liquid coating liquid is not particularly limited as long as it exhibits a liquid state, and may be any of water-based, water-dispersed, solvent-based, and solvent-free.

The liquid (coating liquid) having a lower viscosity is advantageous because it easily penetrates into the damaged part of the polarizer. The viscosity measured at 25 ° C. is preferably 2000 mPa · s or less, more preferably 1000 mPa · s or less, further preferably 500 mPa · s or less, and further 100 mPa · s. It is preferable that:

In forming the transparent resin layer, after applying a liquid material containing the resin component, the resin component is solidified according to the type. The liquid substance containing the resin component is a solution obtained by dissolving or dispersing the resin component in a solvent, and is used as, for example, an aqueous solution, an aqueous dispersion, or a solvent solution. The solidification means forming a resin layer by removing a solvent from the liquid material. For example, when the resin component is a polyvinyl alcohol-based resin, the liquid material can be used as an aqueous solution and can be solidified by heating or the like. Further, when the resin component is water-soluble acrylic, it can be solidified similarly.

On the other hand, in forming the transparent resin layer, after applying a liquid material containing a curable component capable of constituting the resin, the curable component forms a resin according to the type of the curable component. Can be cured. The liquid material containing a curable component that can constitute the resin can be used in a solventless system as long as the curable component exhibits a liquid material. The liquid material may be a solution in which the curable component is dissolved in a solvent. In addition, when the said curable component exhibits a liquid substance, it can be used as a solution. The solvent can be appropriately selected according to the curable component to be used. For example, when an acrylic monomer that forms an acrylic resin is used as the curable component, or when an epoxy monomer that forms an epoxy resin is used, the liquid material containing the curable component is irradiated with active energy rays (ultraviolet rays). Curing by irradiation) or the like can be performed.

The transparent resin layer is preferably formed by applying a liquid material containing a resin component dissolved or dispersed in water to a polarizer and then solidifying the liquid material. The resin component dissolved or dispersed in water refers to a resin dissolved in water at room temperature (25 ° C.) or a resin soluble in water dissolved in an aqueous solvent. It is advantageous that the coating liquid is aqueous or water-dispersed because the surface of the polarizer swells so that the coating liquid becomes compatible with the damaged part. That is, when the coating liquid is an aqueous or water-dispersed system, the orientation of the polyvinyl alcohol molecules around the damaged part constituting the polarizer is partially relaxed and the boric acid content around the damaged part is reduced. Therefore, even if the thickness of the transparent resin layer is small (for example, less than 3 μm, preferably 2 μm or less), the expansion of the damaged portion can be effectively suppressed.

Representative examples of resin components that can be dissolved or dispersed in water include, for example, polyvinyl alcohol resin, poly (meth) acrylic acid, polyacrylamide, methylolated melamine resin, methylolated urea resin, resol type phenolic resin, Examples thereof include ethylene oxide and carboxymethyl cellulose. These may be used alone or in combination. As the resin component, polyvinyl alcohol resin, poly (meth) acrylic acid, and methylolated melamine are preferably used. In particular, a polyvinyl alcohol resin is suitable as the resin component from the viewpoint of adhesion to the polyvinyl alcohol resin constituting the polarizer. Below, the case where a polyvinyl alcohol-type resin is used is demonstrated.

The transparent resin layer is preferably formed from a forming material containing a polyvinyl alcohol-based resin. The polyvinyl alcohol resin forming the transparent resin layer may be the same as or different from the polyvinyl alcohol resin contained in the polarizer as long as it is a “polyvinyl alcohol resin”.

The thickness of the transparent resin layer formed from a forming material containing a polyvinyl alcohol-based resin is preferably 0.2 μm or more, from the viewpoint of repairing damage generated on the surface of the polarizer and maintaining optical properties. The thickness of the transparent resin layer is preferably 0.5 μm or more, and more preferably 0.7 μm or more. On the other hand, when the transparent resin layer becomes too thick, the optical reliability and water resistance are lowered. Therefore, the thickness of the transparent resin layer is preferably 3 μm or less, more preferably less than 3 μm, and further 2 μm or less. Is preferred.

Examples of the polyvinyl alcohol resin include polyvinyl alcohol. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. Examples of the polyvinyl alcohol-based resin include a saponified product of a copolymer of vinyl acetate and a monomer having copolymerizability. When the copolymerizable monomer is ethylene, an ethylene-vinyl alcohol copolymer is obtained. Examples of the copolymerizable monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid, and esters thereof; ethylene, propylene, and the like. α-olefin, (meth) allylsulfonic acid (soda), sulfonic acid soda (monoalkylmalate), disulfonic acid soda alkylmalate, N-methylolacrylamide, acrylamide alkylsulfonic acid alkali salt, N-vinylpyrrolidone, N- Examples include vinyl pyrrolidone derivatives. These polyvinyl alcohol resins can be used alone or in combination of two or more.

The saponification degree of the polyvinyl alcohol-based resin can be, for example, 95 mol% or more, but from the viewpoint of satisfying moisture heat resistance and water resistance, the saponification degree is preferably 99 mol% or more, Is preferably 99.7 mol% or more. The degree of saponification represents the proportion of units that are actually saponified to vinyl alcohol units among the 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 determined according to JIS K 6726-1994.

The average degree of polymerization of the polyvinyl alcohol-based resin can be, for example, 500 or more. From the viewpoint of satisfying the heat and moisture resistance and water resistance, the average degree of polymerization is preferably 1000 or more, and more preferably 1500 or more. Is preferable, and 2000 or more is more preferable. The average degree of polymerization of the polyvinyl alcohol resin is measured according to JIS-K6726.

As the polyvinyl alcohol resin, a modified polyvinyl alcohol resin having a hydrophilic functional group in the side chain of the polyvinyl alcohol or a copolymer thereof can be used. Examples of the hydrophilic functional group include an acetoacetyl group and a carbonyl group. In addition, modified polyvinyl alcohol obtained by acetalization, urethanization, etherification, grafting, phosphoric esterification or the like of a polyvinyl alcohol resin can be used.

The ratio of the polyvinyl alcohol resin in the transparent resin layer or the forming material (solid content) is preferably 80% by weight or more, more preferably 90% by weight or more, and further preferably 95% by weight or more.

The forming material is prepared as a solution in which the polyvinyl alcohol resin is dissolved in a solvent. Examples of the solvent include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide N-methylpyrrolidone, various glycols, polyhydric alcohols such as trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. These may be used alone or in combination of two or more. Among these, it is preferable to use it as an aqueous solution using water as a solvent. The concentration of the polyvinyl alcohol-based resin in the forming material (for example, an aqueous solution) is not particularly limited, but is 0.1 to 15% by weight, preferably 0.5%, in consideration of coating properties and storage stability. ~ 10% by weight.

In addition, as for the said forming material (for example, aqueous solution), a plasticizer, surfactant, etc. are mentioned as an additive, for example. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of the surfactant include nonionic surfactants. Furthermore, coupling agents such as silane coupling agents and titanium coupling agents, various tackifiers, ultraviolet absorbers, antioxidants, heat stabilizers, hydrolysis stabilizers, and other stabilizers can be added.

The transparent resin layer can be formed by applying and drying the forming material on the other surface of the polarizer (the surface not having the protective film). The forming material is applied so that the thickness after drying is 0.2 μm or more. The application operation is not particularly limited, and any appropriate method can be adopted. For example, various means such as a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, a knife coating method (comma coating method, etc.) can be employed. The drying temperature is usually preferably 60 to 200 ° C, and more preferably 70 to 120 ° C. The drying time is preferably 10 to 1800 seconds, more preferably 20 to 600 seconds.

Next, in the formation of the transparent resin layer, a case where a liquid material containing a curable component capable of constituting a resin is used will be described. The curable component can be roughly classified into an active energy ray curable type such as an electron beam curable type, an ultraviolet ray curable type, and a visible light curable type, and a thermosetting type. Furthermore, the ultraviolet curable type and the visible light curable type can be classified into a radical polymerization curable type and a cationic polymerization curable type. In the present invention, an active energy ray having a wavelength range of 10 nm to less than 380 nm is expressed as ultraviolet light, and an active energy ray having a wavelength range of 380 nm to 800 nm is expressed as visible light. The radical polymerization curable component can be used as a thermosetting curable component.

≪Radical polymerization curable forming material≫
Examples of the curable component include a radical polymerizable compound. Examples of the radical polymerizable compound include compounds having a radical polymerizable functional group of a carbon-carbon double bond such as a (meth) acryloyl group and a vinyl group. As these curable components, either a monofunctional radical polymerizable compound or a bifunctional or higher polyfunctional radical polymerizable compound can be used. Moreover, these radically polymerizable compounds can be used individually by 1 type or in combination of 2 or more types. As these radically polymerizable compounds, for example, compounds having a (meth) acryloyl group are suitable. In the present invention, (meth) acryloyl means an acryloyl group and / or methacryloyl group, and “(meth)” has the same meaning hereinafter.

≪Monofunctional radical polymerizable compound≫
Examples of the monofunctional radical polymerizable compound include (meth) acrylamide derivatives having a (meth) acrylamide group. The (meth) acrylamide derivative is preferable in terms of ensuring adhesion with the polarizer and having a high polymerization rate and excellent productivity. Specific examples of (meth) acrylamide derivatives include, for example, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N N-alkyl group-containing (meth) acrylamide derivatives such as butyl (meth) acrylamide and N-hexyl (meth) acrylamide; N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-methylol-N— N-hydroxyalkyl group-containing (meth) acrylamide derivatives such as propane (meth) acrylamide; N-aminoalkyl group-containing (meth) acrylamide derivatives such as aminomethyl (meth) acrylamide and aminoethyl (meth) acrylamide; N-methoxymethyl N-alkoxy group-containing (meth) acrylamide derivatives such as acrylamide and N-ethoxymethylacrylamide; N-mercaptoalkyl group-containing (meth) acrylamide derivatives such as mercaptomethyl (meth) acrylamide and mercaptoethyl (meth) acrylamide; It is done. Examples of the heterocyclic-containing (meth) acrylamide derivative in which the nitrogen atom of the (meth) acrylamide group forms a heterocyclic ring include, for example, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine. Etc.

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

In addition, examples of the monofunctional radical polymerizable compound include various (meth) acrylic acid derivatives having a (meth) acryloyloxy group. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl ( (Meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl ( (Meth) acrylate, n-o Tadeshiru (meth) (meth) acrylic acid (1-20 carbon atoms) such as acrylates alkyl esters.

Examples of the (meth) acrylic acid derivative include cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate and cyclopentyl (meth) acrylate;
Aralkyl (meth) acrylates such as benzyl (meth) acrylate;
2-isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, dicyclo Polycyclic (meth) acrylates such as pentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and the like;
2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) Examples thereof include alkoxy groups such as acrylates and alkylphenoxypolyethylene glycol (meth) acrylates or phenoxy group-containing (meth) acrylates.

Examples of the (meth) acrylic acid derivative include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4- Hydroxyalkyl (meth) acrylates such as hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, etc. And hydroxyl groups such as [4- (hydroxymethyl) cyclohexyl] methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, etc. 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) acrylate, octafluoropentyl (meth) ) Halogen-containing (meth) acrylates such as acrylate, heptadecafluorodecyl (meth) acrylate, 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) acrylate, 3-hexyloxetanylmethyl (meta) ) Oxetane group-containing (meth) acrylates such as acrylates;
(Meth) acrylates having a heterocyclic ring such as tetrahydrofurfuryl (meth) acrylate, butyrolactone (meth) acrylate, neopentyl glycol (meth) acrylic acid adducts such as hydroxypivalate, p-phenylphenol (meth) acrylate, etc. Can be mentioned.

Also, 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.

Examples of the monofunctional radical polymerizable compound include lactam vinyl monomers such as N-vinyl pyrrolidone, N-vinyl-ε-caprolactam, and methyl vinyl pyrrolidone; vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, Examples thereof include vinyl monomers having a nitrogen-containing heterocyclic ring such as vinyl pyrrole, vinyl imidazole, vinyl oxazole and vinyl morpholine.

Also, as the monofunctional radically polymerizable compound, a radically polymerizable compound having an active methylene group can be used. The radical polymerizable compound having an active methylene group is a compound having an active methylene group having an active double bond group such as a (meth) acryl group at the terminal or in the molecule. Examples of the active methylene group include an acetoacetyl group, an alkoxymalonyl group, and a cyanoacetyl group. The active methylene group is preferably an acetoacetyl group. Specific examples of the radical polymerizable compound having an active methylene group include 2-acetoacetoxyethyl (meth) acrylate, 2-acetoacetoxypropyl (meth) acrylate, 2-acetoacetoxy-1-methylethyl (meth) acrylate, and the like. Acetoacetoxyalkyl (meth) acrylate; 2-ethoxymalonyloxyethyl (meth) acrylate, 2-cyanoacetoxyethyl (meth) acrylate, N- (2-cyanoacetoxyethyl) acrylamide, N- (2-propionylacetoxybutyl) Examples include acrylamide, N- (4-acetoacetoxymethylbenzyl) acrylamide, and N- (2-acetoacetylaminoethyl) acrylamide. The radical polymerizable compound having an active methylene group is preferably acetoacetoxyalkyl (meth) acrylate.

≪Polyfunctional radical polymerizable compound≫
Examples of the bifunctional or higher polyfunctional radical polymerizable compound include 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) Acryte, cyclic trimethylolpropane formal (meth) acrylate, dioxane glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta Esterified products of (meth) acrylic acid and polyhydric alcohols such as (meth) acrylate, dipentaerythritol hexa (meth) acrylate, EO-modified diglycerin tetra (meth) acrylate, 9,9-bis [4- (2- (Meth) acryloyloxyethoxy) phenyl] fluorene. Specific examples include Aronix M-220, M-306 (manufactured by Toagosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DCP- A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer) and the like. Moreover, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various (meth) acrylate monomers, and the like are included as necessary.

The radical polymerizable compound is preferably used in combination with a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound from the viewpoint of achieving both adhesion to the polarizer and optical durability. Usually, it is preferable to use a combination of 3 to 80% by weight of the monofunctional radical polymerizable compound and 20 to 97% by weight of the polyfunctional radical polymerizable compound with respect to 100% by weight of the radical polymerizable compound.

≪Aspects of radical polymerization curable forming material≫
The radical polymerization curable forming material can be used as an active energy ray curable forming material or a thermosetting forming material. When using an electron beam or the like for the active energy ray, the active energy ray curable forming material does not need to contain a photopolymerization initiator, but when using ultraviolet rays or visible light for the active energy ray, It preferably contains a photopolymerization initiator. On the other hand, when the curable component is used as a thermosetting component, the forming material preferably contains a thermal polymerization initiator.

≪Photopolymerization initiator≫
The photopolymerization initiator in the case of using the radical polymerizable compound is appropriately selected depending on the active energy ray. In the case of curing by ultraviolet light or visible light, a photopolymerization initiator for ultraviolet light or visible light cleavage is used. Examples of the photopolymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone; 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2 -Propyl) ketone, aromatic ketone compounds such as α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexyl phenyl ketone; methoxyacetophenone, 2,2-dimethoxy- Acetophenone compounds such as 2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2-morpholinopropane-1; benzoin methyl ether; Benzoin ethyl ether, benzoin Benzoin ether compounds such as isopropyl ether, benzoin butyl ether and anisoin methyl ether; aromatic ketal compounds such as benzyldimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; 1-phenone-1 , 1-propanedione-2- (o-ethoxycarbonyl) oxime, etc .; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone Thioxanthone compounds such as Son, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; camphorquinone; halogenated ketone; Inokishido; and acyl phospholipase diisocyanate, and the like.

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

Also, when using a visible light curable type containing a radical polymerizable compound as a curable component, it is preferable to use a photopolymerization initiator that is particularly sensitive to light of 380 nm or more. A photopolymerization initiator that is highly sensitive to light of 380 nm or more will be described later.

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

(Wherein R ¹ and R ² represent —H, —CH ₂ CH ₃ , —iPr or Cl, and R ¹ and R ² may be the same or different), respectively, or a general formula ( It is preferable to use together the compound represented by 1) and a photopolymerization initiator that is highly sensitive to light of 380 nm or more, which will be described later. When the compound represented by the general formula (1) is used, the adhesion is excellent as compared with the case where a photopolymerization initiator having high sensitivity to light of 380 nm or more is used alone. Among the compounds represented by the general 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 general formula (1) in the forming material is preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the total amount of the curable component, and preferably 0.5 to 4 parts. More preferred are parts by weight, and even more preferred is 0.9 to 3 parts by weight.

Further, it is preferable to add a polymerization initiation assistant as necessary. Examples of polymerization initiators include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, etc. Among them, ethyl 4-dimethylaminobenzoate is particularly preferable. When a polymerization initiation assistant is used, its addition amount is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component. is there.

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

In particular, as a photopolymerization initiator, in addition to the photopolymerization initiator of the general formula (1), a compound represented by the following general 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 it. As the compound represented by the general formula (2), 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (trade name: IRGACURE907 manufacturer: BASF) which is also a commercial product is suitable. Can be used. 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 preferred because of its high sensitivity.

≪Thermal polymerization initiator≫
As the thermal polymerization initiator, those in which polymerization does not start by thermal cleavage are preferable. For example, as the thermal polymerization initiator, those having a 10-hour half-life temperature of 65 ° C. or higher, more preferably 75 to 90 ° C. are preferable. The half-life is an index representing the decomposition rate of the polymerization initiator, and means the time until the remaining amount of the polymerization initiator is halved. 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 catalog, for example, “Organic peroxide catalog 9th edition by Nippon Oil & Fats Co., Ltd.” (May 2003) ".

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-butyl peroxyneodecanoate (10-hour half-life temperature: 48 ° C.), t-hexyl peroxy Pivalate, t-butylperoxypivalate, dilauroyl peroxide (10 hour half-life temperature: 64 ° C.), di-n-

octanoyl peroxide

1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (10-hour half-life temperature: 66 ° C.), di (4-methylbenzoyl) peroxide, dibenzoyl peroxide (half-hour 10 hours) Organic peroxide such as t-butyl peroxyisobutyrate (10-hour half-life temperature: 81 ° C.), 1,1-di (t-hexylperoxy) cyclohexane, and the like.

Examples of the thermal polymerization initiator include 2,2′-azobisisobutyronitrile (10 hour half-life temperature: 67 ° C.), 2,2′-azobis (2-methylbutyronitrile) (10 hours). And azo compounds such as 1,1-azobis-cyclohexane-1-carbonitrile (10 hour half-life temperature: 87 ° C.).

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

≪Cation polymerization curable forming material≫
Examples of the curable component of the cationic polymerization curable forming material include compounds having an epoxy group or an oxetanyl group. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various generally known curable epoxy compounds can be used. As a preferable epoxy compound, a compound having at least two epoxy groups and at least one aromatic ring in the molecule (aromatic epoxy compound), or at least two epoxy groups in the molecule, at least one of them. Examples thereof include a compound (alicyclic epoxy compound) formed between two adjacent carbon atoms constituting an alicyclic ring.

≪Photo cationic polymerization initiator≫
The cationic polymerization curable forming material contains the epoxy compound and the oxetane compound described above as the curable component, and both of these are cured by cationic polymerization, and therefore, a photocationic polymerization initiator is blended therein. This cationic photopolymerization initiator generates a cationic species or a Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and starts a polymerization reaction of an epoxy group or an oxetanyl group.

The formation of the transparent resin layer by the curable forming material is performed by coating the curable forming material on the surface of the polarizer and then curing.

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 saponification treatment.

The coating method of the curable forming material is appropriately selected depending on the viscosity of the curable forming material and the target thickness. Examples of coating methods include reverse coaters, gravure coaters (direct, reverse and offset), bar reverse coaters, roll coaters, die coaters, bar coaters, rod coaters and the like. In addition, for coating, a method such as a dapping method can be appropriately used.

<Curing of forming material>
The curable forming material is used as an active energy ray curable forming material or a thermosetting forming material. The active energy ray curable forming material can be used in an electron beam curable type, an ultraviolet curable type, or a visible light curable type. The aspect of the curable forming material is preferably an active energy ray curable forming material rather than a thermosetting forming material from the viewpoint of productivity, and moreover, the active energy ray curable forming material is a visible light curable forming material. It is preferable from the viewpoint of productivity.

≪Active energy ray curing type≫
In the active energy ray curable forming material, after applying the active energy ray curable forming material to the polarizer, the active energy ray (electron beam, ultraviolet ray, visible light, etc.) is irradiated, and the active energy ray curable forming material is applied. Curing to form a transparent resin layer. The irradiation direction of active energy rays (electron beam, ultraviolet ray, visible light, etc.) can be irradiated from any appropriate direction. Preferably, it irradiates from the transparent resin layer side.

≪Electron beam curing type≫
In the electron beam curable type, any appropriate condition can be adopted as the electron beam irradiation condition as long as the active energy ray curable forming material can be cured. For example, in the electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the deepest part of the transparent resin layer and may be insufficiently cured. If the acceleration voltage exceeds 300 kV, the penetration force through the sample is too strong, and a protective film or polarizer May cause damage. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the adhesive is insufficiently cured, and when it exceeds 100 kGy, the protective film and the polarizer are damaged, resulting in a decrease in mechanical strength and yellowing, thereby obtaining predetermined optical characteristics. Can not.

The electron beam irradiation is usually performed in an inert gas, but if necessary, it may be performed in the atmosphere or under a condition where a little oxygen is introduced.

≪Ultraviolet curing type, visible light curing type≫
In the method for producing a polarizing film according to the present invention, active energy rays containing visible light having a wavelength range of 380 nm to 450 nm, particularly active energy rays having the largest irradiation amount of visible light having a wavelength range of 380 nm to 450 nm are used as active energy rays. It is preferable. As the active energy ray according to the present invention, a gallium-encapsulated metal halide lamp and an LED light source that emits light in the wavelength range of 380 to 440 nm are preferable. Or low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, incandescent lamp, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excimer laser or sunlight A light source including visible light can be used, and ultraviolet light having a wavelength shorter than 380 nm can be blocked using a band pass filter.

≪Thermosetting type≫
On the other hand, in the thermosetting type forming material, by heating, polymerization is started by a thermal polymerization initiator to form a cured product layer. The heating temperature is set according to the thermal polymerization initiator, but is about 60 to 200 ° C., preferably 80 to 150 ° C.

<Step (5)>
As described above, the transparent resin layer 4 of the polarizing film (or the piece-protecting polarizing film B) obtained by the production method of the present invention is laminated with an adhesive layer, and the polarizing film with the adhesive layer (or the piece-protecting polarizing film). Film C) can be produced. A separator can be provided in the pressure-sensitive adhesive layer of the polarizing film with the pressure-sensitive adhesive layer (or the piece protective polarizing film C).

<Adhesive layer>
An appropriate pressure-sensitive adhesive can be used for forming the pressure-sensitive adhesive layer, and the type thereof is not particularly limited. Adhesives include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, Examples thereof include cellulose-based pressure-sensitive adhesives.

Among these pressure-sensitive adhesives, those having excellent optical transparency, suitable wettability, cohesiveness, and adhesive pressure characteristics, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used as one exhibiting such characteristics.

As a method for forming the pressure-sensitive adhesive layer, for example, a method in which the pressure-sensitive adhesive is applied to a release-treated separator, the polymerization solvent is dried and removed to form a pressure-sensitive adhesive layer, and then transferred to a polarizer or a polarizer. The pressure-sensitive adhesive is applied to the film, and the polymerization solvent is dried and removed to form a pressure-sensitive adhesive layer on the polarizer. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be added as appropriate.

A silicone release liner is preferably used as the release-treated separator. In the step of forming the pressure-sensitive adhesive layer by applying and drying the pressure-sensitive adhesive of the present invention on such a liner, an appropriate method may be adopted as appropriate according to the purpose. Preferably, a method of heating and drying the coating film is used. The heating and drying temperature is preferably 40 ° C to 200 ° C, more preferably 50 ° C to 180 ° C, and particularly preferably 70 ° C to 170 ° C. By setting the heating temperature within the above range, an adhesive having excellent adhesive properties can be obtained.

Appropriate time can be adopted as the drying time. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

Various methods are used as a method for forming the pressure-sensitive adhesive layer. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

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

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a peeled sheet (separator) until practical use.

Examples of the constituent material of the separator include, for example, plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and laminates thereof. A thin film can be used, but a plastic film is preferably used because of its excellent surface smoothness.

The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride co-polymer are used. Examples thereof include a polymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. For the separator, if necessary, mold release and antifouling treatment with a silicone type, fluorine type, long chain alkyl type or fatty acid amide type release agent, silica powder, etc., coating type, kneading type, vapor deposition type It is also possible to carry out antistatic treatment such as. In particular, the release property from the pressure-sensitive adhesive layer can be further improved by appropriately performing a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the separator.

<Surface protection film>
A surface protective film can be provided on the polarizing film of the present invention (including a piece protective polarizing film and a polarizing film with an adhesive layer). The surface protective film usually has a base film and an adhesive layer, and protects the polarizer via the adhesive layer.

As the base film of the surface protective film, a film material having isotropic property or close to isotropic property is selected from the viewpoints of inspection property and manageability. Examples of film materials include polyester resins such as polyethylene terephthalate film, cellulose resins, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, acrylic resins, and the like. Examples thereof include transparent polymers such as resins. Of these, polyester resins are preferred. The base film can be used as a laminate of one kind or two or more kinds of film materials, and a stretched product of the film can also be used. The thickness of the base film is generally 500 μm or less, preferably 10 to 200 μm.

The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer of the surface protective film includes a (meth) acrylic polymer, a silicone-based polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine-based or a rubber-based pressure-sensitive adhesive. Can be appropriately selected and used. 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 (dry film thickness) of the pressure-sensitive adhesive layer is determined according to the required adhesive force. Usually, it is about 1 to 100 μm, preferably 5 to 50 μm.

The surface protective film can be provided with a release treatment layer on the surface opposite to the surface on which the pressure-sensitive adhesive layer is provided on the base film, using a low adhesion material such as silicone treatment, long-chain alkyl treatment, or fluorine treatment. .

<Other optical layers>
The polarizing film of the present invention (including a piece protective polarizing film and a polarizing film with a pressure-sensitive adhesive layer) of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited. For example, for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), and a viewing angle compensation film. One or more optical layers that may be used can be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film in which a reflective plate or a semi-transmissive reflective plate is further laminated on the piece protective polarizing film of the present invention, an elliptical polarizing film in which a retardation plate is further laminated on the polarizing film, or A circular viewing film, a wide viewing angle polarizing film in which a viewing angle compensation film is further laminated on the polarizing film, or a polarizing film in which a brightness enhancement film is further laminated on the polarizing film are preferable.

An optical film obtained by laminating the above optical layer on the polarizing film of the present invention (including a piece protective polarizing film and a polarizing film with an adhesive layer) is also formed by a method of sequentially laminating separately in the manufacturing process of liquid crystal display devices and the like. However, the optical film laminated in advance is excellent in quality stability and assembly work, and has the advantage of improving the manufacturing process of liquid crystal display devices and the like. For the lamination, an appropriate adhesive means such as a pressure-sensitive adhesive layer can be used. When adhering the polarizing film with the pressure-sensitive adhesive layer and other optical films, their optical axes can be arranged at an appropriate angle depending on the intended retardation characteristics and the like.

The polarizing film (including a piece protective polarizing film and a polarizing film with an adhesive layer) or an optical film of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, a polarizing film with an adhesive layer or an optical film, and an illumination system as necessary, and incorporating a drive circuit. In the invention, there is no particular limitation except that the polarizing film of the present invention (including a piece protective polarizing film and a polarizing film with a pressure-sensitive adhesive layer) or an optical film according to the present invention is used. As the liquid crystal cell, an arbitrary type such as an IPS type or a VA type can be used, but is particularly suitable for the IPS type.

A liquid crystal display device in which the polarizing film of the present invention (including a single protective polarizing film and a polarizing film with a pressure-sensitive adhesive layer) or an optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight or reflector used in an illumination system An appropriate liquid crystal display device such as can be formed. In that case, the polarizing film (including a piece protective polarizing film and a polarizing film with an adhesive layer) or an optical film of the present invention can be installed on one side or both sides of the liquid crystal cell. When the polarizing film of the present invention (including a piece protective polarizing film and a polarizing film with a pressure-sensitive adhesive layer) or an optical film is provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples shown below. In addition, all the parts and% in each example are based on weight. The room temperature standing conditions not specifically defined below are all 23 ° C. and 65% RH.

<Viscosity measurement>
The viscosity of the aqueous solution (coating solution) which is a liquid was measured using a VISCOMETER R85 viscometer RE85L (manufactured by Toki Sangyo Co., Ltd.) under the following conditions.
Measurement temperature: 25 ° C
Rotation speed: 0.5-100rpm
Cone rotor: 1 ° 34 '× R24

<Forming material for transparent resin layer>
(Polyvinyl alcohol-based forming material: PVA-A)
A polyvinyl alcohol resin having a polymerization degree of 2500 and a saponification degree of 99.7 mol% was dissolved in pure water to prepare an aqueous solution (coating liquid) having a solid content concentration of 4% by weight and a viscosity of 60 mPa · S.

(Polyvinyl alcohol-based forming material: PVA-B)
A polyvinyl alcohol resin having a polymerization degree of 500 and a saponification degree of 96.0 mol% was dissolved in pure water to prepare an aqueous solution (coating liquid) having a solid content concentration of 4% by weight and a viscosity of 60 mPa · S.

(Polyvinyl alcohol-based forming material :: PVA-C)
A polyvinyl alcohol resin having a polymerization degree of 2500 and a saponification degree of 99.7 mol% was dissolved in pure water to prepare an aqueous solution (coating liquid) having a solid content concentration of 8 wt% and a viscosity of 1500 mPa · S.

(Acrylic forming material A: Solvent-free)
The following materials were mixed at 50 ° C. and stirred for 1 hour to prepare a coating solution having a viscosity of 20 mPa · S.
N-hydroxyethylacrylamide (trade name “HEAA” manufactured by Kojin Co., Ltd.) 20 parts Urethane acrylate (trade name “UV-1700B” manufactured by Nippon Synthetic Chemical Co., Ltd.) 80 parts Photoradical polymerization initiator (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, manufactured by BASF, trade name “IRGACURE907”) 3 parts Photosensitizer (diethylthioxanthone, manufactured by Nippon Kayaku Co., Ltd., trade name “KAYACURE DETX-S” ]) 2 parts

(Acrylic-based forming material B: solvent-based)
In preparing the acrylic forming material A, methyl ethyl ketone was added to prepare a coating solution having a viscosity of 10 mPa · S. Methyl ethyl ketone was adjusted so that the ratio of the acrylic forming material A in the solution was 40% in the preparation of the acrylic forming material B.

(Acrylic forming material C: aqueous)
900 parts of pure water was added to 100 parts of Jurimer FC-80 (manufactured by Toagosei Co., Ltd.) to prepare an aqueous solution (coating solution) having a solid content concentration of 3% and a viscosity of 10 mPa · S.

(Composition of epoxy-based forming material A: no solvent)
The following materials were mixed at 50 ° C. and stirred for 1 hour to prepare a coating solution having a viscosity of 10 mPa · S.
3 ′, 4′-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (Daicel Chemical Industries, trade name “Celoxide 2021P”) 100 parts Photocationic polymerization initiator (4- (phenylthio) phenyldiphenylsulfonium hexafluorophosphate , Made by Sun Apro, trade name "CPI-100P")

<Protective film (acrylic) and adhesive>
A (meth) acrylic resin film having a lactone ring structure with a thickness of 40 μm was subjected to corona treatment on the easy adhesion treated surface.

As an adhesive applied to the protective film (acrylic), 40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO), and 3 parts by weight of a photoinitiator “IRGACURE 819” (manufactured by BASF) Were mixed to prepare an ultraviolet curable adhesive.

<Protective film (TAC) and adhesive>
A triacetyl cellulose film having a thickness of 80 μm (TD80UL, manufactured by Fuji Film Co., Ltd.) was used.

As an adhesive applied to the protective film (TAC), a polyvinyl alcohol resin containing an acetoacetyl group (average polymerization degree: 1200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%) With respect to 100 parts, 50 parts of methylol melamine was dissolved in pure water under a temperature condition of 30 ° C. to prepare an aqueous solution adjusted to a solid content concentration of 3.7%. An aqueous adhesive solution was prepared by adding 18 parts of an aqueous colloidal alumina solution (average particle size 15 nm, solid content concentration 10%, positive charge) to 100 parts of the aqueous solution.

Example 1
(Step 1: Preparation of Laminate (a)>
As a transport film, a long, amorphous phthalate copolymerized polyethylene terephthalate (PET) film with a water absorption of 0.75% and Tg of 75 ° C. (trade name “Novaclear”, thickness 100 μm, manufactured by Mitsubishi Chemical Corporation) Using.
One side of the transport film is subjected to corona treatment, and on this corona-treated surface, 90 parts by weight of polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl). An aqueous solution containing 10 parts by weight of a modification degree of 4.6%, a saponification degree of 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., and trade name “Gosefimer Z200”) was applied and dried at 60 ° C. to obtain a thickness. A 10 μm PVA resin layer (coating type) was formed to produce a laminate (a ′).
The obtained laminate (a ′) was uniaxially stretched at a free end 1.8 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120 ° C. (air-assisted stretching).
Next, the laminate was immersed 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) for 30 seconds (insolubilization treatment).
Next, it is immersed for 60 seconds in a dyeing bath having a liquid temperature of 30 ° C. (an iodine aqueous solution obtained by blending 0.2 parts by weight of iodine and 1.0 part by weight of potassium iodide with respect to 100 parts by weight of water). (Staining treatment).
Subsequently, it was immersed for 30 seconds in a crosslinking bath having a liquid temperature of 30 ° C. (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). (Crosslinking treatment).
Thereafter, the laminate was immersed in a boric acid aqueous solution (an aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70 ° C. However, uniaxial stretching was performed in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds (underwater stretching). Here, the draw ratio was adjusted so that the thickness of the obtained polarizer was 5 μm.
Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 30 ° C. (cleaning treatment).
As described above, a laminate (a) including a polarizer having a thickness of 5 μm was obtained on the transport film.

(Step 4: Lamination of protective film: production of a piece protective polarizing film A ′ with a transport film)
Subsequently, the ultraviolet curable adhesive was applied to the surface of the polarizer of the laminate (a) so that the thickness of the adhesive layer after curing was 1 μm, and the protective film (acrylic) was bonded. After that, ultraviolet rays were applied as active energy rays to cure the adhesive. Ultraviolet irradiation is performed using a gallium-encapsulated metal halide lamp, an irradiation device: Fusion UV Systems, Inc. Light HAMMER 10, Inc., bulb: V bulb, peak illuminance: 1600 mW / cm ² , integrated irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm) ), And the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell.
As described above, a piece protective polarizing film A ′ with a transport film was produced. The optical properties of the obtained piece-protecting polarizing film A ′ with a transport film were a transmittance of 42.8% and a polarization degree of 99.99%.

(Process 2: Peeling of film for conveyance)
Subsequently, the film for conveyance was peeled from the piece protection polarizing film A 'with a film for conveyance, and the piece protection polarizing film A was obtained.

(Step 3: Production of a piece protective polarizing film B with a transparent resin layer)
The polyvinyl alcohol system adjusted to 25 ° C. as a transparent resin layer forming material on the polarizer surface (polarizer surface on which no protective film is provided) of the single protective polarizing film A from which the transport film has been peeled off The forming material (PVA-A) was applied with a wire bar so that the thickness after drying was 1 μm, and then dried with hot air at 85 ° C. for 25 seconds to prepare a piece protective polarizing film B with a transparent resin layer.

Examples 2 to 15 and Comparative Examples 1 to 4
In Example 1, the piece-protecting polarizing film B with a transparent resin layer was used in the same manner as in Example 1 except that the materials, thicknesses, and means for forming each layer used in each step were changed as shown in Table 1. Was made.

In Table 1, with respect to the transport film in the step (1), in Examples 3 and 4, it is a long, amorphous isophthalic acid copolymerized polyethylene terephthalate (PET) film having a water absorption of 0.75% and a Tg of 75 ° C. (Mitsubishi Chemical Co., Ltd., trade name “NOVA CLEAR”, thickness 38 μm) was used and provided with the following pressure-sensitive adhesive layer X. The pressure-sensitive adhesive layer X was used by transferring a pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet prepared by the following method. In the step (1), a PVA-based resin layer was formed or a PVA film was bonded to the pressure-sensitive adhesive layer to produce a laminate (a ′).

<Formation of adhesive layer X>
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, condenser, and dropping funnel, 96 parts of 2-ethylhexyl acrylate (2EHA), 4 parts of 2-hydroxyethyl acrylate (HEA), polymerization started 2,2′-azobisisobutyronitrile as an agent and 150 parts by mass of ethyl acetate were charged, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was kept at around 65 ° C. A polymerization reaction was carried out for 6 hours to prepare an acrylic polymer (a) solution (40%). The glass transition temperature calculated from the Fox formula of this acrylic polymer (a) was −68 ° C., and the weight average molecular weight was 550,000.
On the other hand, 100 parts by mass of toluene, 40 parts of dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), 60 parts of methyl methacrylate (MMA) and methyl thioglycolate as a chain transfer agent Five parts were put into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, a cooler, and a dropping funnel. Then, after stirring for 1 hour at 70 ° C. in a nitrogen atmosphere, 0.2 part by mass of azobisisobutyronitrile as a thermal polymerization initiator was added and reacted for 2 hours at 70 ° C., followed by 4 at 80 ° C. After reacting for an hour, it was reacted at 90 ° C. for 1 hour. The obtained (meth) acrylic polymer 1 had a glass transition temperature calculated from the Fox formula of 130 ° C. and a weight average molecular weight of 4300.
The (meth) acrylic polymer 1 is added to 500 parts of the (meth) acrylic polymer (a) solution (35%) diluted to 20% with ethyl acetate (100 parts of the (meth) acrylic polymer (a)). 1 part by mass, as an ionic compound, 0.03 part of bis (trifluoromethanesulfonyl) imide lithium (manufactured by Tokyo Chemical Industry Co., Ltd., LiTFSI), as a compound having a polyoxyalkylene chain, an organopolysiloxane having a polyoxyalkylene chain ( Product name: KF6004, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 parts, coronate L (trimethylolpropane / tolylene diisocyanate trimer adduct 75% ethyl acetate solution, manufactured by Nippon Polyurethane Industry Co., Ltd.) 2 0.0 part, 3 mass of 1% solid content ethyl acetate solution of dioctyltin dilaurate as a crosslinking catalyst Was added, pressure-sensitive adhesive composition performed mixed and stirred for about 5 minutes at 25 ° C. (1) was prepared.

(Preparation of adhesive sheet)
The pressure-sensitive adhesive composition (1) was applied to the surface opposite to the antistatic treatment surface of a polyethylene terephthalate film with an antistatic treatment layer (trade name: Diafoil T100G38, manufactured by Mitsubishi Plastics, Inc., thickness 38 μm). The mixture was heated at 0 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 15 μm. Next, a silicone-treated surface of a release liner (20 μm thick polyethylene terephthalate film with one side subjected to silicone treatment) was bonded to the surface of the pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet.

In Table 1, regarding Examples 5 and 6 and Comparative Example 2, a polyethylene (PE) film (manufactured by Toray Film Processing Co., Ltd., Tretec 7332, thickness 31 μm) was used for the transport film in step (1). In Example 7, a polypropylene (PP) film (manufactured by Toray Industries Inc., Treffan 2500H, thickness 60 μm) was used.

In Table 1, with respect to the method of forming the polarizer in step (1), in Examples 2, 4, and 6, the PVA-based resin layer (coating type) was formed in Example 1 when producing the laminate (a ′). Instead, a polyvinyl alcohol film (film type) having an average polymerization degree of 2400, a saponification degree of 99.9 mol%, and a thickness of 20 μm was bonded to the transport film. The obtained laminate (a ′) was treated in the same manner as in Example 1 to obtain a laminate (a) containing a 7 μm thick polarizer after stretching.

In Table 1, with respect to step (4), in Examples 5 and 6, a protective film (TAC) was bonded to the surface of the polarizer using an adhesive aqueous solution. After bonding the protective film (TAC), drying was performed at 50 ° C. for 5 minutes. The adhesive layer was adjusted so that the thickness after drying was 0.1 μm.

In Table 1, regarding the step (3), when a polyvinyl alcohol-based forming material was used as the forming material for the transparent resin layer, the heating time, heating temperature, and film thickness shown in Table 1 were employed. On the other hand, when acrylic forming material A or epoxy forming material A is used as the forming material of the transparent resin layer (Examples 11 and 14), the forming material is made to have a thickness of 5 μm using a wire bar coater. After coating, a piece protective polarizing film B with a transparent resin layer was produced by irradiating active energy rays in a nitrogen atmosphere. As an active energy ray, visible light (gallium filled metal halide lamp) Irradiation device: Fusion UV Systems, Inc. Light HAMMER10 bulb: V bulb Peak illuminance: 1600 mW / cm ² , integrated irradiation dose 1000 / mJ / cm ² (wavelength 380-440 nm) was used. The illuminance of visible light was measured using a Sola-Check system manufactured by Solatell.
Moreover, when the acrylic type forming material B (solvent type) was used as the forming material of the transparent resin layer (Example 12), after the coating, it was dried in an oven at 60 ° C. for 1 second, and then the solvent was removed. In the same manner as above, active energy rays were irradiated in a nitrogen atmosphere to form a transparent resin layer.
Moreover, when the acrylic type forming material C (aqueous type) was used as the forming material of the transparent resin layer (Example 13), it was dried in an oven at 90 ° C. for 60 seconds after coating to form a transparent resin layer.

In Comparative Examples 1 and 2, the step (3) (formation of a transparent resin layer) was not performed.
In Comparative Example 3, instead of forming a transparent resin layer, only water was applied and a drying process was performed.
In Comparative Example 4, the step (3) (formation of a transparent resin layer) was performed with a thickness of 0.1 μm.
In Comparative Example 5, the film for conveyance could not be conveyed because it was not used.

The following evaluation was performed on the piece protective polarizing film B or the piece protective polarizing film A with a transparent resin layer obtained in the above Examples and Comparative Examples. The results are shown in Table 1.

<Measurement of compression modulus at 80 ° C.>
TI900 TriboIndenter (manufactured by Hystron) was used for the measurement of the compression modulus. The obtained piece-protecting polarizing film B with a transparent resin layer was cut into a size of 10 mm × 10 mm, fixed to a support equipped with a TriboIndenter, and the compression modulus was measured by a nanoindentation method. At that time, the position was adjusted such that the working indenter pushed in the vicinity of the center of the transparent resin layer. The measurement conditions are shown below.
Working indenter: Berkovich (triangular pyramid type)
Measuring method: Single indentation measurement Measuring temperature: 80 ° C
Indentation depth setting: 100 nm

<Single transmittance T and degree of polarization P>
The single transmittance T and polarization degree P of the obtained piece-protecting polarizing film A were measured using a spectral transmittance measuring device with an integrating sphere (Dot-3c of Murakami Color Research Laboratory).
The degree of polarization P is the transmittance when two identical polarizing films are overlapped so that their transmission axes are parallel (parallel transmittance: Tp), and overlapped so that their transmission axes are orthogonal to each other. It is calculated | required by applying the transmittance | permeability (orthogonal transmittance | permeability: Tc) at the time of combining to the following formula | equation. Polarization degree P (%) = {(Tp−Tc) / (Tp + Tc)} ^1/2 × 100
Each transmittance is represented by a Y value obtained by correcting visibility with a two-degree field of view (C light source) of JIS Z8701, with 100% of the completely polarized light obtained through the Granteller prism polarizer.

<Transportability>
In step (1), whether or not the laminate (a ′) was able to be transported when subjected to underwater stretching (wet stretching step) was determined based on the following criteria.
○: Can be transported.
Δ: Can be transported, but cracks to the extent that it can be transported to the end of the polarizer.
X: Cannot be transported due to breakage.

<Durability: Light leakage defect: Number of occurrences>
The piece protective polarizing film B with a transparent resin layer obtained in Examples 1 to 15 and Comparative Example 4 and the piece protective polarizing film A obtained in Comparative Examples 1 to 3 were arranged so that the absorption axis direction was the longer side. Three pieces cut to inch size were prepared. Similarly, three sheets cut to a 32-inch size so that the absorption axis direction is the short side were prepared. Next, in Examples 1 to 15 and Comparative Example 4, the pressure-sensitive adhesive layer Y formed by the following method having a thickness of 20 μm was provided on the transparent resin layer surface of the piece protective polarizing film B with a transparent resin layer. In Comparative Examples 1 and 2, the pressure-sensitive adhesive layer Y was provided on the surface of the piece protective polarizing film A from which the transport film was peeled off. In Comparative Example 3, the pressure-sensitive adhesive layer Y was provided on the surface of the single protective polarizing film A on which water was applied. In this way, a sample (polarizing film with an adhesive layer) was prepared. The pressure-sensitive adhesive layer Y side of the sample was attached to both surfaces of a non-alkali glass having a thickness of 0.5 mm using a laminator so that the sample was crossed Nicol. Subsequently, the sample was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the sample to the acrylic-free glass. Thus, three 32-inch evaluation samples each having a piece of polarizing protective film B with a transparent resin layer or a piece of polarizing protective film A with a transparent resin layer were prepared. The evaluation sample was treated for 500 hours in each atmosphere at 80 ° C. (heating conditions), and then the number of light spot defects in the three evaluation samples was visually confirmed, and the total number of the samples was as follows. Evaluation based on the criteria.
○: No occurrence.
Δ: 1 to 9 pieces.
X: 10 or more.

<Formation of adhesive layer Y>
In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 100 parts of butyl acrylate, 3 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate and 2,2′-azobisisobutyrate A solution was prepared by adding 0.3 parts of ronitrile with ethyl acetate. Next, the solution was stirred while blowing nitrogen gas and reacted at 55 ° C. for 8 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight of 2.2 million. Furthermore, the acrylic polymer solution which added ethyl acetate to the solution containing this acrylic polymer and adjusted solid content concentration to 30% was obtained.
As a cross-linking agent, 100 parts by weight of the solid content of the acrylic polymer solution is a cross-linking agent mainly composed of a compound having an isocyanate group of 0.5 part (trade name “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.). And 0.075 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KMB-403”) as a silane coupling agent in this order, Was prepared. The pressure-sensitive adhesive solution was applied to the surface of a release sheet (separator) composed of a peeled polyethylene terephthalate film (thickness 38 μm) so that the thickness after drying was 20 μm, dried, and pressure-sensitive adhesive layer Y Formed.

A 'piece protective polarizing film with film for transportation A piece protective polarizing film B piece protective polarizing film with transparent resin layer C piece protective polarizing film with adhesive layer (with transparent resin layer)
DESCRIPTION OF SYMBOLS 1 Polarizer 2 Protective film 3 Film for conveyance 4 Transparent resin layer 5 Adhesive layer

Claims

A step (1) of preparing a laminate (a) having a transport film and a polarizer having a thickness of 10 μm or less containing a polyvinyl alcohol-based resin formed on one surface of the transport film;
Step (2) of peeling the film for conveyance from the laminate (a), and curable resin layer or resin layer on the side of the laminate (a) from which the film for conveyance is peeled off. A polarizing film comprising a step (3) of forming a transparent resin layer having a thickness of 0.2 μm or more by applying a liquid material containing a component and then solidifying or curing the liquid material Production method.
The method for producing a polarizing film according to claim 1, wherein the transparent resin layer has a compressive elastic modulus at 80 ° C of 0.1 GPa or more.
The transparent resin layer formed in the step (3) is formed by applying a liquid material containing a resin component dissolved or dispersed in water and then solidifying. Manufacturing method of the polarizing film.
The method for producing a polarizing film according to claim 3, wherein the liquid material containing the resin component is an aqueous solution containing a polyvinyl alcohol resin.
The method for producing a polarizing film according to any one of claims 1 to 4, wherein the liquid material has a viscosity at 25 ° C of 1000 mPa · s or less.
The laminate (a) in the step (1) comprises at least a stretching step and a dyeing step on a laminate (a ′) having a transport film and a polyvinyl alcohol-based resin layer formed on one side of the transport film. 6. The method for producing a polarizing film according to claim 1, wherein the polarizing film is obtained by applying.
A step (4) of forming a protective film on the polarizer side of the laminate (a);
The method for producing a polarizing film according to any one of claims 1 to 6, wherein a piece-protecting polarizing film having a protective film only on one side of the polarizer is produced as the polarizing film.
The polarizer has an optical characteristic represented by the following formula: P> − (10 0.929T-42.4 −1) × 100 (where T <42.3) Or
8. The method for producing a polarizing film according to claim 1, wherein the polarizing film is configured to satisfy a condition of P ≧ 99.9 (where T ≧ 42.3).
The production of the polarizing film according to any one of claims 1 to 8, further comprising a step (5) of forming an adhesive layer on the side of the transparent resin layer formed in the step (3). Method.