JP6737609B2 - Method for producing one-sided protective polarizing film with adhesive layer - Google Patents

Description

The present invention relates to a method for producing a one-sided protective polarizing film with an adhesive layer. The pressure-sensitive adhesive protective film with a pressure-sensitive adhesive layer obtained by the above-mentioned production method can be used alone or as an optical film obtained by laminating the film to form an image display device such as a liquid crystal display device (LCD) or an organic EL display device.

Liquid crystal display devices are rapidly expanding in markets such as watches, mobile phones, PDAs, notebook computers, personal computer monitors, DVD players, and TVs. The liquid crystal display device visualizes a polarization state due to switching of liquid crystal, and a polarizer is used due to its display principle.

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

An adhesive is usually used when the polarizing film is attached to a liquid crystal cell or the like. In addition, the pressure-sensitive adhesive is preliminarily provided as a pressure-sensitive adhesive layer on one surface of the polarizing film, since it has advantages such as being able to instantly fix the polarizing film and not requiring a drying step to fix the polarizing film. .. That is, a pressure-sensitive adhesive layer-attached polarizing film is generally used for attaching the polarizing film.

On the other hand, image display devices such as liquid crystal display devices are becoming thinner, and polarizing films are also required to be thinner. Therefore, thinning is also performed on the polarizer (Patent Document 1). Further, thinning can be performed by providing a protective film only on one side of the polarizer and using a one-side protective polarizing film having no protective film on the other side. Since the one-sided protective polarizing film has one less protective film than the two-sided protective polarizing film in which the protective films are provided on both sides of the polarizer, it can be made thinner.

On the other hand, since the one-sided protective polarizing film has insufficient durability due to the thermal shock, it is proposed to provide a protective layer (transparent resin layer) on the polarizer side (Patent Documents 2 and 3).

Patent No. 4751481 JP, 2010-009027, A JP, 2013-160775, A

In Patent Documents 2 and 3, thinning is achieved by using a one-sided protective polarizing film having a protective film only on one side of a polarizer, and on the other side, a one-sided protective polarizing film is provided by providing a protective layer. The absorption axis of the polarizer changes due to the change of the contraction stress of the polarizer in a severe environment of a through crack in the absorption axis direction of the polarizer (a heat shock test (for example, a heat shock test in which temperature conditions of −30° C. and 80° C. are repeated). The occurrence of cracks that occur in the entire direction is suppressed. In addition, in Patent Documents 2 and 3, it is described that the protective layer (transparent resin layer) can be formed on the one-sided protective polarizing film by various coating methods.

On the other hand, as described above, thinning is also performed on the polarizer. When the polarizer used for the polarizing film or the polarizing film with the pressure-sensitive adhesive layer is thin (for example, when the thickness is 10 μm or less), the change in shrinkage stress of the polarizer is small. Therefore, it has been found that the thinned polarizer can suppress the occurrence of the through crack.

However, in the one-sided protective polarizing film in which the occurrence of the through cracks is suppressed or the pressure-sensitive adhesive layer-attached polarizing film using the same, when the optical characteristics are controlled as in Patent Document 1 and the polarizer is thinned (for example, When the thickness is 10 μm or less), when a mechanical shock is applied to the one-sided protective polarizing film or the polarizing film with an adhesive layer using the one-sided polarizing film (including the case where a load is applied to the polarizer side due to convex bending), It was found that extremely fine slits (hereinafter, also referred to as nanoslits) are partially generated in the absorption axis direction of the polarizer. It was also found that the nanoslit occurs regardless of the size of the polarizing film. Furthermore, it was also found that the nanoslit does not occur when using both protective polarizing films having protective films on both sides of the polarizer. Further, when a through-crack occurs in the polarizer, the stress around the through-crack is released, so the through-crack does not occur adjacently, but in addition to the nanoslits occurring independently, adjacently. It turned out to occur. Further, it was also found that the through crack has a progressive property extending in the absorption axis direction of the polarizer in which the crack is generated, but the nanoslit does not have the progressive property. Thus, the nanoslit, in the one-sided protective polarizing film in which the occurrence of through cracks is suppressed, is a new problem that occurs when the polarizer is thin, and the optical characteristics are controlled within a predetermined range. It was found that this is a problem caused by a phenomenon different from the above-described through crack.

Further, since the nano slits are extremely thin, they cannot be detected under normal environment. Therefore, even if nano-slits are generated in the polarizer, it is difficult at first glance to confirm defects due to light leakage in the one-sided protective polarizing film and the polarizing film with a pressure-sensitive adhesive layer using the one-side protective polarizing film. That is, usually, the one-sided protective polarizing film is produced in the form of a long film and is subjected to a defect inspection by an automatic optical inspection, but it is difficult to detect the nanoslit as a defect by this defect inspection. The defect due to the nanoslit is that the nanoslit spreads in the width direction when the one-sided protective polarizing film or the polarizing film with an adhesive layer is attached to a glass substrate of an image display panel and then placed in a heating environment. It was also found that the detection becomes possible (for example, the presence or absence of the light leakage).

Therefore, in the one-sided protective polarizing film having a thickness of 10 μm or less or the pressure-sensitive adhesive layer-attached polarizing film using the same, it is desired to suppress not only through cracks but also generation of nano slits.

However, when a thin one-sided protective polarizing film is used, after the transparent resin layer is formed from the coating liquid for the protective layer (transparent resin layer), for example, curing is promoted so that the transparent film is controlled to have a predetermined film thickness. In order to obtain the resin layer, once, the one-sided protective polarizing film with the transparent resin layer is wound into a roll, and the wound one-sided protective polarizing film with the transparent resin layer is unwound again, and then the adhesive layer If it is attempted to shift to the forming step of the step, a stress may be locally applied to the polarizer due to blocking (adhesion between the wound films) when the one-sided protective polarizing film with the transparent resin layer is unwound. Therefore, the roll-shaped product of the obtained one-sided protective polarizing film with a transparent resin layer raises the risk of nano-slits and makes it difficult to feed it to the next step. On the other hand, after forming the transparent resin layer, if the surface protective film is pasted on the transparent resin layer and then wound, blocking due to the transparent resin layer can be prevented, but when the surface protective film is peeled off, the polarizer is used. The local stress increases the risk of nanoslits.

The present invention, even when using a thin one-sided protective film, it is possible to stably form a transparent resin layer, then an adhesive layer, and to suppress the occurrence of nanoslits. An object of the present invention is to provide a method for producing a one-sided protective polarizing film with an agent layer.

As a result of earnest studies, the inventors of the present application have found that the above problems can be solved by the following method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer, and have completed the present invention.

That is, the present invention is a method for producing a one-sided protective polarizing film with an adhesive layer having a transparent resin layer and an adhesive layer in this order from the polarizer side of the one-sided protective polarizing film having a protective film only on one side of the polarizer. There
The polarizer includes a polyvinyl alcohol-based resin, has a thickness of 10 μm or less, and has optical characteristics represented by a single transmittance T and a polarization degree P, which are represented by the following formula P>−(10 ^{0.929T-42. 4} −1)×100 (where T<42.3), or
It is configured to satisfy the condition of P≧99.9 (where T≧42.3),
Formation of the transparent resin layer and the pressure-sensitive adhesive layer,
A step (1) of applying a coating liquid containing a resin component or a curable component capable of forming a resin layer on the side of the polarizer of the one-sided protective polarizing film while conveying the one-sided protective polarizing film; After forming the transparent resin layer by performing the step (2) of solidifying or curing the coating liquid after the coating step (1),
The pressure-sensitive adhesive layer is obtained by performing the step (3) of forming the pressure-sensitive adhesive layer on the transparent resin layer without winding the obtained one-sided protective polarizing film with the transparent resin layer into a roll. And a method for producing a one-sided protective polarizing film.

In the method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer, a step (4) of measuring the film thickness of a transparent resin layer in a conveyance line after the step (2) and before the step (3). Can have. The step (4) can be performed by an optical interference method using a polarizing element at the tip of the light source.

In the method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer, by using a coating liquid containing a resin component dissolved or dispersed in water as the coating liquid in the step (1), solidifying in the step (2) A transparent resin layer can be formed. The coating liquid containing the resin component is preferably an aqueous solution containing a polyvinyl alcohol resin.

In the method for producing a pressure-sensitive adhesive protective film with a pressure-sensitive adhesive layer, the coating liquid in step (1) preferably has a viscosity at 25° C. of 1000 mPa·s or less.

In the method for producing a one-sided protective polarizing film with an adhesive layer, the polarizer preferably contains boric acid in an amount of 20% by weight or less based on the total amount of the polarizer.

In the method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer, a separator may be laminated on the pressure-sensitive adhesive layer and used. The one-sided protective polarizing film with a pressure-sensitive adhesive layer provided with a separator can be obtained as a wound body.

The one-sided protective polarizing film with a pressure-sensitive adhesive layer obtained by the production method of the present invention uses a polarizer having a thickness of 10 μm or less and is made thin. Further, the thin polarizer having a thickness of 10 μm or less has a smaller change in shrinkage stress applied to the polarizer due to thermal shock, as compared with the case where the thickness of the polarizer is large, so that the occurrence of through cracks can be suppressed.

On the other hand, in a thin polarizer having predetermined optical characteristics, nanoslits are likely to occur in the polarizer. Nanoslit is a process for producing a polarizing film with a pressure-sensitive adhesive layer, which comprises providing a pressure-sensitive adhesive layer on a one-sided protective polarizing film, in various steps after producing a polarizing film with a one-sided protective layer, the one-sided protective polarizing film or adhesive using the same It is considered that this occurs when a mechanical shock is applied to the agent layer-attached polarizing film, and it is assumed that it is caused by a mechanism different from the through crack caused by thermal shock. Further, the defects due to the nano slits, when the protective film with a pressure-sensitive adhesive layer is attached to the glass substrate of the image display panel and placed in a heating environment, the nano slits spread in the width direction. Can be detected (for example, the presence or absence of the light leakage).

In the one-sided protective polarizing film with the pressure-sensitive adhesive layer obtained by the production method of the present invention, the other side of the polarizer (the side not having the protective film) is provided with a transparent resin layer, thereby suppressing the generation of the nanoslits. can do.

According to the production method of the present invention, after the transparent resin layer is formed by the step (1) and the step (2) on the one-sided protective film using a thin polarizer, the one-sided protection with the obtained transparent resin layer is obtained. The polarizing film is once wound into a roll, and the wound one-sided protective polarizing film with the transparent resin layer is not unwound again, and the process is transferred to the next step (3) to obtain the transparent resin. An adhesive layer is formed on the layer. Thus, in the production method of the present invention, since it does not have a winding step and a payout step of the one-sided protective polarizing film with the transparent resin layer, the nanoslit due to the blocking of the one-sided protective polarizing film with the transparent resin layer. The one-sided protective polarizing film with the pressure-sensitive adhesive layer can be manufactured continuously and stably without increasing the risk of occurrence of

Further, in the production method of the present invention, after the step (2) and before the step (3), a step (4) of measuring the film thickness of the transparent resin layer for the one-sided protective polarizing film with the transparent resin layer. Can be provided. By the step (4), the film thickness of the transparent resin layer can be stably measured without winding the one-sided protective polarizing film with the transparent resin layer into a roll, and the transparent resin layer has a predetermined film thickness. Can be managed to be. As a result, it is not necessary to check the film thickness management off-line, which improves productivity.

It is a conceptual diagram which shows an example of embodiment which concerns on the manufacturing method of this invention. It is a conceptual diagram which shows one form which concerns on process (4) in the manufacturing method of this invention. It is an example of the conceptual diagram which compares the nano slit which arises in a polarizer, and a penetration crack.

Hereinafter, steps (1) to (3) of the method for producing a one-sided protective polarizing film with an adhesive layer of the present invention will be described with reference to FIG. 1.

In the coating step (1), the coating liquid 2'is applied to the one-sided protective polarizing film 1 being conveyed. The one-sided protective polarizing film 1 has the protective film 20 on only one surface of the polarizer 10, and is represented by a configuration of the polarizer 10/the protective film 20. In FIG. 1, the coating liquid 2 ′ is shown as being applied (directly) to the polarizer of the one-sided protective polarizing film 1. The one-sided protective polarizing film 1 is usually preferably transported at 5 to 50 m/min, more preferably 10 to 40 m/min. In the solidifying or curing step (2), the transparent resin layer 2 is formed from the coating liquid 2'to obtain the one-sided protective polarizing film A with the transparent resin layer. Then, the transparent resin layer-attached one-sided protective film A is subjected to the step (3) of forming the pressure-sensitive adhesive layer 3 on the transparent resin layer 2 without winding the polarizing film A into a roll, and the one-sided protective layer-attached protective film. The polarizing film B is manufactured.

Further, as shown in FIG. 1, in the manufacturing method of the present invention, after the step (2) and before performing the step (3), a step (4) of measuring the film thickness of the transparent resin layer in the transport line is performed. ) Can be included. As shown in FIG. 2, the step (4) can be performed by an optical interference method using a polarizing element 41 between the light source 40 and the one-sided protective polarizing film. The light source 40 is installed so as to be vertical from the transparent resin layer 2 side of the one-sided protective polarizing film A with the transparent resin layer. A polarizing element 41 is used between the light source 40 and the one-sided protective polarizing film A with the transparent resin layer so that the light source 40 has an absorption axis orthogonal to the polarizer 10 of the one-sided protective polarizing film A with the transparent resin layer. The thickness of the transparent resin layer 2 is measured by the optical interference method.

Although not shown, a separator can be provided on the pressure-sensitive adhesive layer of the one-sided protective polarizing film B with the pressure-sensitive adhesive layer of the present invention. Further, a surface protective film can be provided on the side of the protective film 20 of the one-sided protective polarizing film B with the pressure-sensitive adhesive layer of the present invention. The one-sided protective polarizing film with an adhesive layer having at least a separator (further, one having a surface protective film) can be used as a wound body, for example, an adhesive fed from the wound body and conveyed by the separator. By applying the layered polarizing film to the surface of the image display panel via an adhesive layer (also referred to as "roll-to-panel method", typically applied to Japanese Patent No. 446043), The image display device can be manufactured continuously.

FIG. 3 is a conceptual diagram comparing the nanoslit a generated in the polarizer with the through crack b. 3A shows the nanoslit a generated in the polarizer 10, and FIG. 3B shows the through crack b generated in the polarizer 10. The nanoslit a is generated by mechanical shock and partially generated in the absorption axis direction of the polarizer 10. The nanoslit a cannot be confirmed at the beginning, but in a thermal environment (for example, 80° C. or 60° C., 90% RH), it can be confirmed by the spread in the width direction. On the other hand, it is considered that the nanoslit a does not have the progressive property of extending in the absorption axis direction of the polarizer. Further, it is considered that the nano slits a occur regardless of the size of the polarizing film. The nanoslits a may be generated independently, or may be generated adjacently. On the other hand, the through crack b is generated by thermal shock (for example, heat shock test). The through crack has a property of extending in the absorption axis direction of the polarizer in which the crack has occurred. When the through crack b occurs, the stress in the periphery is released, and therefore the through crack does not occur adjacently.

<Step (1)>
≪One-sided protective polarizing film≫
As the one-sided protective polarizing film, one having a protective film only on one side of a thin polarizer is used. Further, the one-sided protective polarizing film preferably has a thickness (total thickness) of 60 μm or less. Even in such a thin one-sided protective film, the transparent resin layer having a stable film thickness can be formed by the manufacturing method of the present invention. The thickness of the one-sided protective polarizing film may be 55 μm or less. On the other hand, the thickness of the thin one-sided protective film is preferably 20 μm or more, and more preferably 25 μm or more from the viewpoint of transportability.

≪Polarizer≫
In the present invention, a polarizer having a thickness of 10 μm or less is used. The thickness of the polarizer is preferably 8 μm or less, more preferably 7 μm or less, and further preferably 6 μm or less from the viewpoint of thinning and suppressing the occurrence of through cracks. On the other hand, the thickness of the polarizer is preferably 2 μm or more, more preferably 3 μm or more. Such a thin polarizer has little thickness unevenness and excellent visibility, and since it has little dimensional change, it has excellent durability against thermal shock.

A polarizer using a polyvinyl alcohol resin is used as the polarizer. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene/vinyl acetate copolymer partially saponified films, and dichroic dyes such as iodine and dichroic dyes. Examples thereof include polyene-based oriented films such as substances adsorbed and uniaxially stretched, polyvinyl alcohol dehydration products, polyvinyl chloride dehydrochlorination products, and the like. Among these, a polarizer made of a polyvinyl alcohol film and a dichroic substance such as iodine is preferable.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. If necessary, boric acid, zinc sulfate, zinc chloride, etc. may be contained, or the solution may be immersed in an aqueous solution of potassium iodide or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, it is possible to wash the stains and anti-blocking agent on the surface of the polyvinyl alcohol-based film, and by swelling the polyvinyl alcohol-based film, the effect of preventing unevenness such as uneven dyeing is also obtained. is there. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. Stretching can be performed in an aqueous solution of boric acid or potassium iodide or in a water bath.

The polarizer preferably contains boric acid from the viewpoint of stretching stability and optical durability. Further, the content of boric acid contained in the polarizer is preferably 20% by weight or less, more preferably 18% by weight or less, and further preferably 18% by weight or less with respect to the total amount of the polarizer from the viewpoint of suppressing the occurrence of through cracks and suppressing expansion. It is preferably 16% by weight or less. On the other hand, from the viewpoint of stretching stability and optical durability of the polarizer, the boric acid content is preferably 10% by weight or more, and more preferably 12% by weight or more, based on the total amount of the polarizer.

As a thin polarizer, typically,
Patent No. 4751486 specification,
Patent No. 4751481,
Japanese Patent No. 4815544,
Japanese Patent No. 5048120,
International Publication 2014/0775599 pamphlet,
International Publication 2014/077636 pamphlet,
And the thin polarizers obtained from the production methods described therein.

The polarizer has optical characteristics represented by a single transmittance T and a degree of polarization P of the following formula P>−(10 ^0.929 T ^−42.4 −1)×100 (where T<42.3), Or
It is configured to satisfy the condition of P≧99.9 (where T≧42.3). The polarizer configured so as to satisfy the above conditions has the performance uniquely 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 brightness is 500 cd/m ² or more. As another application, for example, it is attached to the viewing side of the organic EL display device.

As the thin polarizer, among manufacturing methods including a step of stretching in the state of a laminated body and a step of dyeing, in that it can be stretched at a high magnification and the polarization performance can be improved, Japanese Patent No. 4751486 Specification, Patent Those obtained by a production method including a step of stretching in an aqueous solution of boric acid as described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544 are preferable, and particularly those described in Japanese Patent Nos. 4751481 and 4815544 are described. What is obtained by a production method including a step of auxiliary stretching in the air before stretching in a boric acid aqueous solution is preferable. These thin polarizers can be obtained by a production method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a stretching resin base material in a laminate state and a dyeing step. According to this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without trouble such as breakage due to stretching because it is supported by the stretching resin base material.

≪Protective film≫
As a material forming the protective film, a material having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. For example, polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose, acrylic-based polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples thereof include a polymer and a polycarbonate polymer. Further, 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. , Polyethersulfone-based polymer, polyetheretherketone-based polymer, polyphenylene sulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, epoxy-based polymer, or the above Blends of polymers and the like are also mentioned as examples of the polymer forming the protective film. These protective films are usually attached to the polarizer with an adhesive layer.

The protective film may contain one or more kinds of any appropriate additive. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, an anti-coloring agent, 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, further preferably 60 to 98% by mass, and particularly preferably 70 to 97% by mass. When the content of the thermoplastic resin in the protective film is 50% by mass or less, the high transparency originally possessed by the thermoplastic resin may not be sufficiently exhibited.

As the protective film, a retardation film, a brightness enhancement film, a diffusion film or the like can also be used. Examples of the retardation film include those having a front surface retardation of 40 nm or more and/or 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. When a retardation film is used as the protective film, the retardation film also functions 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, the stretching ratio, etc. are appropriately set depending on the retardation value, the material of the film, and the thickness.

The thickness of the protective film can be appropriately determined, but generally it is preferably 2 to 200 μm, more preferably 3 to 100 μm in view of workability such as strength and handleability, and thin layer property. Is preferred. In particular, in order to adjust the thickness (total thickness) of the one-sided protective polarizing film to 60 μm or less, the thickness of the protective film (when the film is previously formed) is preferably 15 to less than 60 μm from the viewpoint of transportability, Furthermore, 20-55 μm is preferable. On the other hand, the thickness of the protective film (when formed by coating and curing) is preferably 3 to 50 μm, and more preferably 5 to 40 μm from the viewpoint of transportability. The protective film may be used in a plurality of layers or 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 may be provided on the surface of the protective film to which the polarizer is not adhered. The hard coat layer, the antireflection layer, the antisticking layer, the functional layer such as the diffusion layer and the antiglare layer may be provided on the protective film itself, or may be provided separately from the protective film. it can.

<Intervening layer>
The protective film and the polarizer can be laminated via an intervening layer such as an adhesive layer, a pressure-sensitive adhesive layer, and an undercoat layer (primer layer). At this time, it is desirable that both layers are laminated without an air gap by an intervening layer. The intervening layer between the polarizer 1 and the protective film 2 is not shown in FIG.

The adhesive layer is formed of an adhesive. The type of 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, and as the adhesive, various forms such as water-based, solvent-based, hot melt-based and active energy ray-curable adhesives are used. Alternatively, an active energy ray-curable adhesive is suitable.

Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, 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 is cured by active energy rays such as electron beams and ultraviolet rays (radical curable type, cation curable type), and is, for example, an electron beam curable type or an ultraviolet ray curable type. Can be used. As the active energy ray curable adhesive, for example, a photo radical curable adhesive can be used. When the photoradical-curable active energy ray-curable adhesive is used as an ultraviolet curable adhesive, the adhesive contains a radical-polymerizable compound and a photopolymerization initiator.

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

Further, when the water-based adhesive or the like is used, the application of the adhesive is preferably performed 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, it is preferable that the thickness of the adhesive layer is 0.2 to 20 μm.

In addition, in laminating the polarizer and the protective film, an easily adhesive layer can be provided between the protective film and the adhesive layer. The easy-adhesion layer can be formed of 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, or the like. These polymer resins may be used alone or in combination of two or more. Further, other additives may be added to form the easily adhesive layer. Specifically, a tackifier, a UV absorber, an antioxidant, a stabilizer such as a heat stabilizer and the like may be used.

The easy-adhesion layer is usually provided in advance on the 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 a material for forming the easy-adhesion layer onto the protective film by a known technique and drying. The material for forming the easy-adhesion layer is usually prepared as a solution diluted to an appropriate concentration in consideration of the thickness after drying and the smoothness of coating. The easily-adhesive layer has a thickness after drying of preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and further preferably 0.05 to 1 μm. A plurality of easy-adhesion layers can be provided, but in this case as well, it is preferable that the total thickness of the easy-adhesion layers be within the above range.

The adhesive layer is formed from an adhesive. As the pressure-sensitive adhesive, various pressure-sensitive adhesives can be used, for example, 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, poly-based pressure-sensitive adhesives. Examples thereof include acrylamide adhesives and cellulose adhesives. An adhesive base polymer is selected according to the type of the adhesive. Among the pressure-sensitive adhesives, an acrylic pressure-sensitive adhesive is preferably used because it is excellent in optical transparency, exhibits appropriate wettability, cohesiveness, and adhesive property of adhesiveness and is excellent in weather resistance and heat resistance. It

The undercoat layer (primer layer) is formed in order to improve the adhesion between the polarizer and the protective film. The material forming the primer layer is not particularly limited as long as it is a material that 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 acrylic resins, polyolefin resins, polyester resins, polyvinyl alcohol resins, and mixtures thereof.

<<Coating liquid>>
The coating liquid contains a resin component or a curable component capable of forming a resin layer. A transparent resin layer is formed by the coating liquid.

The form of the coating liquid which is the coating liquid is not particularly limited as long as it shows a liquid state, and may be any of water-based, water-dispersed, solvent-based and solvent-free.

The coating liquid having a lower viscosity is advantageous because it easily penetrates into the damaged portion of the polarizer. The viscosity 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, as measured at 25° C. The following is preferable.

The coating liquid is preferably applied to the one-sided protective polarizing film (polarizer side) so that the thickness of the transparent resin layer formed after the step (2) is 0.2 μm or more. The thickness of the transparent resin layer is preferably 0.5 μm or more, more preferably 0.7 μm or more. On the other hand, if the transparent resin layer is too thick, the optical reliability and water resistance are deteriorated. Therefore, the thickness of the transparent resin layer is preferably 3 μm or less, more preferably less than 3 μm, and further preferably 2 μm or less. Is preferred.

Examples of the material for forming the transparent resin layer include polyester resin, polyether resin, polycarbonate resin, polyurethane resin, silicone resin, polyamide resin, polyimide resin, PVA resin, acrylic resin, epoxy. Examples of the resin include an isocyanate resin and an isocyanate resin. These resin materials may be used alone or in combination of two or more, and among them, at least one selected from the group consisting of polyurethane resin, PVA resin, acrylic resin and epoxy resin. Are preferred, and PVA-based resins and acrylic-based resins are more preferred.

The coating liquid is preferably a coating liquid containing a resin component dissolved or dispersed in water. The resin component dissolved or dispersed in water means a resin dissolved in water or a resin soluble in water dissolved in an aqueous solvent at room temperature (25° C.). It is advantageous that the coating liquid is water-based or water-dispersed because the surface of the polarizer swells and the coating liquid fits in the damaged portion. That is, when the coating liquid is water-based or water-dispersed, the orientation of the polyvinyl alcohol molecules around the damaged portion that constitutes the polarizer is partly relaxed, and the boric acid content around the damaged portion 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), enlargement of the damaged portion can be effectively suppressed.

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

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

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. Examples of the polyvinyl alcohol-based resin include saponified products of a copolymer of vinyl acetate and a monomer having copolymerizability. When the monomer having copolymerizability is ethylene, an ethylene-vinyl alcohol copolymer is obtained. Examples of the copolymerizable monomers include (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, unsaturated carboxylic acids such as (meth)acrylic acid and esters thereof; ethylene, propylene and the like. α-Olefin, (meth)allyl sulfonic acid (soda), sodium sulfonate (monoalkyl malate), sodium disulfonic acid alkyl malate, N-methylol acrylamide, acrylamide alkyl sulfonic acid alkali salt, N-vinyl pyrrolidone, N- Examples thereof include vinylpyrrolidone 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 may be, for example, 95 mol% or more, but the saponification degree is preferably 99 mol% or more from the viewpoint of satisfying wet heat resistance and water resistance. Is preferably 99.7 mol% or more. The degree of saponification represents the proportion of units actually saponified into vinyl alcohol units among units that can be converted into vinyl alcohol units by saponification, and the residue is a vinyl ester unit. The saponification degree can be determined according to JIS K 6726-1994.

The average degree of polymerization of the polyvinyl alcohol-based resin may be, for example, 500 or more, but from the viewpoint of satisfying wet heat resistance and water resistance, the average degree of polymerization is preferably 1,000 or more, and more preferably 1500 or more. Is preferable, and more preferably 2000 or more. The average degree of polymerization of the polyvinyl alcohol resin is measured according to JIS-K6726.

As the polyvinyl alcohol-based resin, a modified polyvinyl alcohol-based resin having a hydrophilic functional group in the side chain of the polyvinyl alcohol or its copolymer can be used. Examples of the hydrophilic functional group include an acetoacetyl group and a carbonyl group. In addition, a modified polyvinyl alcohol obtained by converting a polyvinyl alcohol resin into an acetal, urethane, ether, graft, phosphoric ester, or the like can be used.

The proportion of the polyvinyl alcohol-based 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 coating liquid 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 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 coatability and leaving stability. 10 to 10% by weight.

In addition, examples of the additive in the coating liquid (for example, aqueous solution) include a plasticizer and a surfactant. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of the surfactant include nonionic surfactants. Further, a coupling agent such as a silane coupling agent and a titanium coupling agent, various tackifiers, an ultraviolet absorber, an antioxidant, a heat stabilizer, a hydrolysis stabilizer, and the like can be added.

The coating liquid is preferably applied so that the thickness after drying is 0.2 μm or more. The coating operation is not particularly limited, and any appropriate method can be adopted. For example, gravure coating method (direct, reverse or offset), roll coating method, spin coating method, wire bar coating method, dip coating method, die coating method, curtain coating method, spray coating method, knife coating method (comma coating method, etc.) Various means such as can be adopted.

Next, a case where a coating liquid containing a curable component capable of forming a resin is used for forming the transparent resin layer 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 ray curable type, and a heat curable type. Further, the ultraviolet curing type and the visible light curing type can be classified into a radical polymerization curing type and a cationic polymerization curing type. In the present invention, an active energy ray having a wavelength range of 10 nm to less than 380 nm is indicated as an ultraviolet ray, and an active energy ray having a wavelength range of 380 nm to 800 nm is indicated as a visible ray. The radical polymerization curable component can be used as a thermosetting curable component.

<<Radical Polymerization Curing Material>>
Examples of the curable component include radically polymerizable compounds. Examples of the radically polymerizable compound include compounds having a radically 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 radically polymerizable compound or a bifunctional or more polyfunctional radically 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 addition, in this invention, (meth)acryloyl means an acryloyl group and/or a methacryloyl group, and "(meth)" has the same meaning below.

<<Monofunctional Radical Polymerizable Compound>>
Examples of the monofunctional radically polymerizable compound include (meth)acrylamide derivatives having a (meth)acrylamide group. The (meth)acrylamide derivative is preferable in terms of ensuring the adhesiveness with the polarizer and also in that the polymerization rate is high and the productivity is excellent. Specific examples of the (meth)acrylamide derivative include, for example, N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N. -N-alkyl group-containing (meth)acrylamide derivatives such as -butyl (meth)acrylamide, 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; To be Examples of the heterocycle-containing (meth)acrylamide derivative in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle 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, and N-hydroxyethyl (meth)acrylamide is particularly preferable, from the viewpoint of adhesion to the polarizer.

Examples of the monofunctional radically 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( Examples thereof include (meth)acrylic acid (C 1-20) alkyl esters such as (meth)acrylate and n-octadecyl (meth)acrylate.

Examples of the (meth)acrylic acid derivative include cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate;
Aralkyl (meth)acrylates such as benzyl (meth)acrylate;
2-isobornyl(meth)acrylate, 2-norbornylmethyl(meth)acrylate, 5-norbornen-2-yl-methyl(meth)acrylate, 3-methyl-2-norbornylmethyl(meth)acrylate, 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, ethylcarbitol (meth)acrylate, phenoxyethyl (meth) Alkoxy groups such as acrylate and alkylphenoxy polyethylene glycol (meth)acrylate or phenoxy group-containing (meth)acrylate; and the like.

Moreover, as said (meth)acrylic acid derivative, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4- Hydroxyalkyl (meth)acrylates such as hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate and 12-hydroxylauryl (meth)acrylate. Or a hydroxyl group-containing (meth)acrylate such as [4-(hydroxymethyl)cyclohexyl]methyl acrylate, cyclohexanedimethanol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate;
Epoxy group-containing (meth)acrylate such as glycidyl (meth)acrylate, 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 (meth) ) Oxetane group-containing (meth)acrylates such as acrylates;
Heterocyclic (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and butyrolactone (meth)acrylate, hydroxypivalic acid neopentyl glycol (meth)acrylic acid adducts, and p-phenylphenol (meth)acrylate Can be mentioned.

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

Examples of the monofunctional radically polymerizable compound include lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, Examples thereof include vinyl-based monomers having a nitrogen-containing heterocycle such as vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine.

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

<<Polyfunctional radically polymerizable compound>>
Examples of difunctional or higher polyfunctional radically polymerizable compounds include tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9. -Nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide adduct di(meth ) Acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, cyclic tri Methylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate , Dipentaerythritol hexa(meth)acrylate, EO-modified diglycerin tetra(meth)acrylate, etc., esterified products of (meth)acrylic acid and polyhydric alcohol, 9,9-bis[4-(2-(meth)acryloyl] And oxyethoxy)phenyl]fluorene. As specific examples, 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- Examples include A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer), and CD-536 (manufactured by Sartomer). If necessary, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, various (meth)acrylate-based monomers, and the like can be mentioned.

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

<<Aspect of radical polymerization curable forming material>>
The radical polymerization curable forming material can be used as an active energy ray curable or thermosetting forming material. When using an electron beam 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 is preferable to contain a photopolymerization initiator. On the other hand, when the curable component is used as the thermosetting component, the forming material preferably contains a thermal polymerization initiator.

<< Photoinitiator >>
The photopolymerization initiator in the case of using a radically polymerizable compound is appropriately selected depending on the active energy ray. In the case of curing with an ultraviolet ray or a visible ray, a photopolymerization initiator capable of cleaving an ultraviolet ray or a visible ray is used. Examples of the photopolymerization initiator include benzyl, benzophenone, benzoylbenzoic acid, benzophenone compounds such as 3,3′-dimethyl-4-methoxybenzophenone; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2) -Propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenyl ketone and other aromatic ketone compounds; methoxyacetophenone, 2,2-dimethoxy- Acetophenone compounds such as 2-phenylacetophenone, 2,2-diethoxyacetophenone and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin methyl ether, Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; aromatic ketal compounds such as benzyldimethyl ketal; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride Compounds; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4- Thioxanthone compounds such as dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone and dodecylthioxanthone; camphorquinone; halogenated Examples include ketones, acylphosphinoxides, acylphosphonates, and the like.

The content of the photopolymerization initiator is 20 parts by weight or less based on 100 parts by weight of the total amount of the curable component (radical polymerizable compound). The compounding 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.

Further, when used in a visible light curable type containing a radically polymerizable compound as a curable component, it is particularly preferable to use a photopolymerization initiator highly sensitive to light of 380 nm or more. The photopolymerization initiator having high sensitivity to light of 380 nm or more will be described later.

（式中、Ｒ^１およびＲ^２は−Ｈ、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^１およびＲ^２は同一または異なっても良い）を単独で使用するか、あるいは一般式（１）で表される化合物と後述する３８０ｎｍ以上の光に対して高感度な光重合開始剤とを併用することが好ましい。一般式（１）で表される化合物を使用した場合、３８０ｎｍ以上の光に対して高感度な光重合開始剤を単独で使用した場合に比べて密着性に優れる。一般式（１）で表される化合物の中でも、Ｒ^１およびＲ^２が−ＣＨ_２ＣＨ_３であるジエチルチオキサントンが特に好ましい。当該形成材中の一般式（１）で表される化合物の組成比率は、硬化性成分の全量１００重量部に対して、０．１〜５重量部であることが好ましく、０．５〜４重量部であることがより好ましく、０．９〜３重量部であることがさらに好ましい。 The photopolymerization initiator is a compound represented by the following general formula (1);

(Wherein R ¹ and R ² represent —H, —CH ₂ CH ₃ , —iPr or Cl, and R ¹ and R ² may be the same or different), or they may be used alone or in the general formula ( It is preferable to use the compound represented by 1) in combination with a photopolymerization initiator having high sensitivity to light having a wavelength 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, and 0.5 to 4 parts by weight, based on 100 parts by weight of the total amount of the curable component. It is more preferably part by weight, and further preferably 0.9 to 3 parts by weight.

Further, it is preferable to add a polymerization initiation auxiliary agent if necessary. As a polymerization initiation aid, triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, etc. And ethyl 4-dimethylaminobenzoate is particularly preferable. When a polymerization initiation aid is used, its addition amount is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, and most preferably 0 to 3 parts by weight, 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, if necessary. Since the protective film having UV absorbing ability does not transmit light having a wavelength of 380 nm or less, it is preferable to use a photopolymerization initiator having high sensitivity to light having a wavelength 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.

（式中、Ｒ^３、Ｒ^４およびＲ^５は−Ｈ、−ＣＨ_３、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^３、Ｒ^４およびＲ^５は同一または異なっても良い）を使用することが好ましい。一般式（２）で表される化合物としては、市販品でもある２−メチル−１−（４−メチルチオフェニル）−２−モルフォリノプロパン−１−オン（商品名：ＩＲＧＡＣＵＲＥ９０７ メーカー：ＢＡＳＦ）が好適に使用可能である。その他、２−ベンジル−２−ジメチルアミノ−１−（４−モルフォリノフェニル）−ブタノン−１（商品名：ＩＲＧＡＣＵＲＥ３６９ メーカー：ＢＡＳＦ）、２−（ジメチルアミノ）−２−［（４−メチルフェニル）メチル］−１−［４−（４−モルホリニル）フェニル］−１−ブタノン（商品名：ＩＲＧＡＣＵＲＥ３７９ メーカー：ＢＡＳＦ）が感度が高いため好ましい。 In particular, as the photopolymerization initiator, a compound represented by the following general formula (2) in addition to the photopolymerization initiator of the general formula (1);

(In the formula, R ³ , R ⁴ and R ⁵ represent —H, —CH ₃ , —CH ₂ CH ₃ , —iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different.) Preference is given to using. 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 commercially available product, is suitable. Can be used for. In addition, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name: IRGACURE369 manufacturer: BASF), 2-(dimethylamino)-2-[(4-methylphenyl) Methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: IRGACURE379 manufacturer: BASF) is preferable because of its high sensitivity.

<< Thermal polymerization initiator >>
As the thermal polymerization initiator, those that do not initiate polymerization by thermal cleavage are preferable. For example, the thermal polymerization initiator preferably has a 10-hour half-life temperature of 65°C or higher, and more preferably 75 to 90°C. The half-life of is an index showing the decomposition rate of the polymerization initiator, and means the time until the remaining amount of the polymerization initiator becomes half. The decomposition temperature for obtaining a half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, for example, “Nippon Oil and Fat Co., Ltd. “Organic peroxide catalog 9th edition”. (May 2003)” and the like.

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-butylperoxy neodecanoate (10-hour half-life temperature: 48°C), t-hexylperoxy Pivalate, t-butylperoxypivalate, dilauroyl peroxide (10-hour half-life temperature: 64° C.), di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2 -Ethyl hexanoate (10 hour half-life temperature: 66°C), di(4-methylbenzoyl) peroxide, dibenzoyl peroxide (10 hour half-life temperature: 73°C), t-butylperoxyisobutyrate (10 Time half-life temperature: 81° C.) and organic peroxides such as 1,1-di(t-hexylperoxy)cyclohexane.

Examples of the thermal polymerization initiator include 2,2′-azobisisobutyronitrile (10-hour half-life temperature: 67° C.), 2,2′-azobis(2-methylbutyronitrile) (10 hours Azo compounds such as half-life temperature: 67° C.) and 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 based on 100 parts by weight of the total amount of the curable component (radical polymerizable compound). The blending amount of the thermal polymerization initiator is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 3 parts by weight.

<<Cationic Polymerization type 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 commonly 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 (aromatic epoxy compound) in the molecule, or at least two epoxy groups in the molecule, and at least one of them Examples thereof include a compound (alicyclic epoxy compound) formed between two adjacent carbon atoms forming an alicyclic ring.

<< Photocationic polymerization initiator >>
The cationic polymerization-curable forming material contains the epoxy compound and the oxetane compound described above as curable components, and since they are both cured by cationic polymerization, a photocationic polymerization initiator is added. This cationic photopolymerization initiator generates a cationic species or a Lewis acid upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays and electron rays, and initiates a polymerization reaction of epoxy groups and oxetanyl groups.

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

<Step (2)>
In the step (2), the transparent resin layer is formed by performing the step (2) of solidifying or curing the coating liquid after the coating step (1).

In forming the transparent resin layer, after applying the coating liquid containing the resin component, the resin component is solidified according to the type. The coating liquid containing the resin component is a solution or dispersion in which the resin component is dissolved in a solvent, and is used as, for example, an aqueous solution, an aqueous dispersion liquid, or a solvent solution. The solidification means forming a resin layer by removing a solvent from the coating liquid. For example, when the resin component is a polyvinyl alcohol resin, the coating liquid 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 similarly solidified.

Usually, the drying temperature is 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.

On the other hand, in forming the transparent resin layer, after applying a coating liquid containing a curable component capable of forming a resin, the curable component forms a resin according to the type of the curable component. Can be cured. The coating liquid containing a curable component that can form the resin can be used in a solvent-free system as long as the curable component exhibits the coating liquid. Further, as the coating liquid, a solution in which the curable component is dissolved in a solvent can be used. In addition, even when the curable component is a coating liquid, it can be used as a solution. The solvent can be appropriately selected depending on the curable component 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 coating liquid containing the curable component is irradiated with active energy rays ( It can be cured by irradiation with ultraviolet rays).

The transparent resin layer is formed by the curable forming material (coating liquid) by applying the curable forming material to the surface of the polarizer and then curing the material.

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

<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 ray curable type, or a visible ray curable type. From the viewpoint of productivity, the aspect of the curable forming material is preferably an active energy ray-curable forming material, more preferably a visible light curable forming material as the active energy ray-curable forming material, rather than a thermosetting type forming material. It is preferable from the viewpoint of productivity.

≪Active energy ray curing type≫
In the active energy ray-curable forming material, after coating the polarizer with the active energy ray-curing forming material, the active energy ray (electron beam, ultraviolet ray, visible light, etc.) is irradiated to form the active energy ray-curing forming material. It is cured to form a transparent resin layer. The active energy ray (electron beam, ultraviolet ray, visible ray, etc.) can be emitted from any appropriate direction. Irradiation is preferably performed 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 it can cure the active energy ray curable forming material. For example, the electron beam irradiation has an acceleration voltage of preferably 5 kV to 300 kV, more preferably 10 kV to 250 kV. If the accelerating voltage is less than 5 kV, the electron beam may not reach the deepest part of the transparent resin layer, resulting in insufficient curing. If the accelerating voltage exceeds 300 kV, the penetrating force through the sample is too strong and the protective film or polarizer is too strong. May damage the. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. If the irradiation dose is less than 5 kGy, the adhesive will be insufficiently cured, and if it exceeds 100 kGy, the protective film and the polarizer will be damaged, resulting in a decrease in mechanical strength and yellowing, and the predetermined optical characteristics may be obtained. Can not.

The electron beam irradiation is usually carried out in an inert gas, but if necessary, it may be carried out in the air or under a condition in which a small amount of oxygen is introduced.

<<UV curing type, visible light curing type>>
In the method for producing a polarizing film according to the present invention, as the active energy ray, one containing visible light in the wavelength range of 380 nm to 450 nm, particularly the active energy ray having the largest irradiation amount of the visible light in the wavelength range of 380 nm to 450 nm is used. It is preferable. As the active energy ray according to the present invention, a gallium-encapsulated metal halide lamp or an LED light source emitting light in the wavelength range of 380 to 440 nm is preferable. Or ultraviolet light such as 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 containing visible light can be used, and a bandpass filter can be used to block ultraviolet rays having a wavelength shorter than 380 nm.

<< thermosetting >>
On the other hand, in the thermosetting type forming material, when it is heated, polymerization is initiated by the 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 (3)>
Then, the transparent protective resin film with the transparent resin layer obtained in the step (2) is subjected to the step (3) of forming the pressure-sensitive adhesive layer on the transparent resin layer without winding the roll-shaped adhesive film to the pressure-sensitive adhesive. A layered polarizing film can be produced. A separator can be provided in the adhesive layer of the polarizing film with an adhesive layer.

<Adhesive layer>
An appropriate pressure-sensitive adhesive can be used to form the pressure-sensitive adhesive layer, and the type thereof is not particularly limited. As the adhesive, a rubber adhesive, an acrylic adhesive, a silicone adhesive, a urethane adhesive, a vinyl alkyl ether adhesive, a polyvinyl alcohol adhesive, a polyvinylpyrrolidone adhesive, a polyacrylamide adhesive, Cellulose adhesives and the like can be mentioned.

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

As a method for forming a pressure-sensitive adhesive layer, for example, a method of applying the pressure-sensitive adhesive to a release-treated separator or the like, forming a pressure-sensitive adhesive layer by drying and removing a polymerization solvent, and then transferring it to a polarizer or a polarizer It is prepared by a method of forming the pressure-sensitive adhesive layer on the polarizer by applying the pressure-sensitive adhesive to the above, and removing the polymerization solvent and the like by drying. When applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly 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 coating the pressure-sensitive adhesive of the present invention on such a liner and drying the pressure-sensitive adhesive, a suitable method can be adopted depending on the purpose. Preferably, a method of overheating and drying the above 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 in the above range, a pressure-sensitive adhesive having excellent pressure-sensitive adhesive properties can be obtained.

As the drying time, an appropriate time can be adopted as appropriate. 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 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 of the method 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 further preferably 5 to 35 μm.

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

As the constituent material of the separator, for example, a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, and a polyester film, a porous material such as paper, cloth, and non-woven fabric, a net, a foamed sheet, a metal foil, and a laminate of these are appropriately used. The thin film may be a thin film, but a plastic film is preferably used because of its excellent surface smoothness.

The plastic film is not particularly limited as long as it is a film capable of protecting the pressure-sensitive adhesive layer, and examples thereof include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, and vinyl chloride. Examples thereof include polymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, ethylene-vinyl acetate copolymer films and the like.

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

<Surface protection film>
The polarizing film of the present invention (including the one-sided protective polarizing film and the pressure-sensitive adhesive layer-attached polarizing film) may be provided with a surface protective film. The surface protection film usually has a substrate film and a pressure-sensitive adhesive layer, and protects the polarizer through the pressure-sensitive 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 the film material include polyester resin such as polyethylene terephthalate film, cellulose resin, acetate resin, polyether sulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin. Examples include transparent polymers such as resins. Of these, polyester resins are preferred. The base film may be used as a laminate of one or two or more film materials, or a stretched product of the film may be used. The thickness of the substrate film is generally 500 μm or less, preferably 10 to 200 μm.

The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer of the surface protective film includes a (meth)acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer as a base polymer. Can be appropriately selected and used. From the viewpoint of transparency, weather resistance, heat resistance, etc., an acrylic pressure-sensitive adhesive containing an acrylic polymer as a base polymer is preferable. The thickness of the adhesive layer (dry film thickness) is determined according to the required adhesive force. It is usually about 1 to 100 μm, preferably 5 to 50 μm.

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

<Other optical layers>
The one-sided protective polarizing film with an adhesive layer of the present invention 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, but for example, for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including a wave plate such as 1/2 or 1/4), and a viewing angle compensation film. One or two or more optical layers that may be used can be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film obtained by further laminating a reflective plate or a semi-transmissive reflective plate on the pressure-sensitive adhesive layer-attached one-sided protective polarizing film of the present invention, and a retardation plate further laminated on the polarizing film. An elliptically polarizing film or a circularly polarizing film, a wide viewing angle polarizing film obtained by further laminating a viewing angle compensation film on the polarizing film, or a polarizing film obtained by further laminating a brightness improving film on the polarizing film.

The optical film obtained by laminating the optical layer on the one-sided protective polarizing film with the pressure-sensitive adhesive layer of the present invention can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. The optical film is excellent in quality stability and assembling work, and has an advantage that the manufacturing process of the liquid crystal display device can be improved. Appropriate adhesion means such as an adhesive layer may be used for lamination. When adhering the above-mentioned one-sided protective polarizing film with a pressure-sensitive adhesive layer and other optical films, their optical axes can be arranged at appropriate angles according to the intended retardation characteristics and the like.

The one-sided protective polarizing film with an adhesive layer or the 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 in a conventional manner. That is, a liquid crystal display device is generally formed by appropriately assembling a component such as a liquid crystal cell, a one-sided protective polarizing film with an adhesive layer or an optical film, and an illumination system as necessary, and incorporating a drive circuit. However, the present invention is not particularly limited except that the pressure-sensitive adhesive layer-attached one-sided protective polarizing film or optical film of the present invention is used in the present invention, and can be in accordance with conventional methods. As the liquid crystal cell, any type such as IPS type and VA type may be used, but the IPS type is particularly preferable.

A liquid crystal display device in which a one-sided protective polarizing film or an optical film with an adhesive layer of the present invention is arranged on one side or both sides of a liquid crystal cell, or a suitable liquid crystal display device such as one using a backlight or a reflector for an illumination system. Can be formed. In that case, the one-sided protective polarizing film with an adhesive layer or the optical film of the present invention can be installed on one side or both sides of a liquid crystal cell. When the one-sided protective polarizing film or the optical film with the pressure-sensitive adhesive layer of the present invention is provided on both sides, they may be the same or different. Furthermore, when forming a liquid crystal display device, for example, a diffusion plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, and other appropriate components are provided at appropriate positions in a single layer or 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 parts and% in each example are based on weight. All room temperature conditions not specified below are 23° C. and 65% RH.

<One-sided protective polarizing film>
(Production of polarizer)
Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and a Tg of 75° C. was corona-treated on one side of the substrate, and the corona-treated surface was treated with polyvinyl chloride. Alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. An aqueous solution containing the trade name "Gosephimmer Z200") in a ratio of 9:1 was applied and dried at 25°C to form a PVA-based resin layer having a thickness of 11 µm, and a laminate was prepared.
The obtained laminate was uniaxially stretched 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120°C (in-air auxiliary stretching treatment).
Next, the laminated body was immersed in an insolubilizing bath having a liquid temperature of 30° C. (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Then, the polarizing plate was immersed in a dyeing bath having a liquid temperature of 30° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 part by weight of iodine was added to 100 parts by weight of water, and 1.0 part by weight of potassium iodide was added, and the resultant was immersed in an aqueous iodine solution for 60 seconds (dyeing treatment). ..
Then, it was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 30° C. (an aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with 100 parts by weight of water). (Crosslinking treatment).
Then, the laminated body was immersed in an aqueous boric acid solution having a liquid temperature of 70° C. (an aqueous solution obtained by mixing 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with 100 parts by weight of water). On the other hand, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) so that the total stretching ratio was 5.5 (underwater stretching treatment).
After that, the laminate was immersed in a cleaning bath having a liquid temperature of 30° C. (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
As described above, an optical film laminate including a polarizer having a thickness of 5 μm was obtained.

(Preparation of protective film)
Protective film: A (meth)acrylic resin film having a lactone ring structure having a thickness of 40 μm was subjected to corona treatment on the surface for easy adhesion treatment and used.

(Preparation of adhesive applied to protective film)
40 parts by weight of N-hydroxyethyl acrylamide (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.

(Preparation of one-sided protective polarizing film)
After bonding the protective film on the surface of the polarizer of the optical film laminate so that the thickness of the adhesive layer after curing is 0.5 μm, the protective film is laminated, and then the active energy is applied. Ultraviolet rays were irradiated as lines to cure the adhesive. Ultraviolet irradiation is performed using a gallium-encapsulated metal halide lamp, irradiation device: Fusion UV Systems, Inc. Light HAMMER 10, bulb: V bulb, peak illuminance: 1600 mW/cm ² , integrated irradiation amount 1000/mJ/cm ² (wavelength 380 to 440 nm). ) Was used, and the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Next, the amorphous PET substrate was peeled off to prepare a one-sided protective polarizing film (total thickness 45.5 μm) using a thin polarizer. The optical properties of the obtained one-sided protective polarizing film were a single substance transmittance of 42.8% and a polarization degree of 99.99%.

<Single body transmittance T and degree of polarization P>
The single-piece transmittance T and the polarization degree P of the obtained one-sided protective polarizing film were measured using a spectral transmittance measuring device with an integrating sphere (Dot-3c, Murakami Color Research Laboratory).
The degree of polarization P is the transmissivity (parallel transmissivity: Tp) when two identical polarizing films are superposed such that their transmission axes are parallel to each other, and they are superposed so that their transmission axes are orthogonal to each other. It is obtained by applying the transmittance (orthogonal transmittance: Tc) in the combined case to the following formula. Polarization degree P(%)={(Tp−Tc)/(Tp+Tc)} ^1/2 ×100
The respective transmittances are shown by the Y value which is the luminosity factor adjusted by the 2 degree visual field (C light source) of JIS Z8701, with 100% of the completely polarized light obtained through the Glan-Teller prism polarizer.

(Material for forming transparent resin layer: coating liquid)
A polyvinyl alcohol resin having a degree of polymerization of 2500 and a degree of saponification 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.

(Preparation of acrylic polymer)
A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser. Further, to 100 parts of the monomer mixture (solid content), 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with ethyl acetate, and nitrogen gas was introduced while gently stirring. After purging with nitrogen, the liquid temperature in the flask was kept at around 60° C. to carry out a polymerization reaction for 7 hours. Then, ethyl acetate was added to the obtained reaction liquid to prepare a solution of an acrylic polymer having a weight average molecular weight of 1.4 million, which was adjusted to a solid content concentration of 30%.

(Preparation of adhesive composition)
To 100 parts of the solid content of the acrylic polymer solution, 0.1 part of trimethylolpropane xylylene diisocyanate (Takenate D110N manufactured by Mitsui Chemicals, Inc.), 0.3 part of dibenzoyl peroxide, and γ-glycidoxy. 0.075 parts of propylmethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-403) was mixed to prepare an acrylic pressure-sensitive adhesive solution.

(Formation of adhesive layer)
Then, the acrylic adhesive solution is uniformly applied to the surface of a polyethylene terephthalate film (separator film) treated with a silicone release agent with a fountain coater and dried for 2 minutes in a constant temperature air-circulation oven at 155°C. Then, an adhesive layer having a thickness of 20 μm was formed on the surface of the separator film.

Example 1
<Preparation of a one-sided protective polarizing film with a transparent resin layer>
A coating device (specifically, a material for forming a transparent resin layer (coating liquid) is applied to the surface of the polarizer of the above-mentioned one-sided protective polarizing film that is transported at 20 m/min (the surface of the polarizer on which the protective film is not provided). Was applied to have a thickness of 1 μm after drying and then dried with hot air at 85° C. for 30 seconds to prepare a one-sided protective polarizing film with a transparent resin layer.

<Preparation of polarizing film with adhesive layer>
Then, without winding the one-sided protective polarizing film with the transparent resin layer obtained above in a roll shape (specifically, after 18 seconds), the transparent resin layer, the release sheet (separator) The pressure-sensitive adhesive layer formed on the release-treated surface of 1 was bonded to produce a pressure-sensitive adhesive layer-attached polarizing film. Then, the polarizing film with an adhesive layer was wound into a roll.

In the examples, after manufacturing the one-sided protective polarizing film with the transparent resin layer, in the production line before laminating the adhesive layer, the device (device for measuring the film thickness: optical spectroscope: Ocean optics manufactured by The thickness of the transparent resin layer was measured using USB2000+, a light source: HL-2000, an optical fiber: ZFQ-12796 (200 μm reflective fiber), a polarizing element: the one-sided protective polarizing film obtained above). The measurement conditions are a measurement wavelength: 450 nm to 800 nm and a transparent resin layer refractive index: 1.51. The film thickness of the transparent resin layer obtained in the example was 1.0±0.1 μm and was stable.

Comparative Example 1
A one-sided protective polarizing film with a transparent resin layer produced in the same manner as in the example was wound into a roll. After that, the roll-shaped product of the one-sided protective polarizing film with the transparent resin layer was tried to be fed out, but it could not be fed out because blocking occurred in the roll-shaped product.

Comparative example 2
A one-sided protective polarizing film with a transparent resin layer, prepared in the same manner as in the example, was wound with a separator to obtain a roll-shaped product. After that, an attempt was made to pay out from a roll-shaped material of the one-sided protective polarizing film with a transparent resin layer, but the adhesiveness between the transparent resin layer and the separator was weak, and the material was rubbed at the time of transportation and ruptured immediately after transportation.

The risk of nanoslits was low in the examples, while the risk of nanoslits was high in the comparative examples.

1 One-sided protective polarizing film 10 Polarizer 20 Protective film 2'Coating liquid 2 Transparent resin layer 3 Adhesive layer 40 Light source 41 Polarizer A One-sided protective polarizing film with transparent resin layer B One-sided protective polarizing film with adhesive layer

Claims (9)

A method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer having a transparent resin layer and a pressure-sensitive adhesive layer in this order from the side of the one-sided protective polarizing film polarizer having a protective film only on one side of the polarizer,
The polarizer includes a polyvinyl alcohol-based resin, has a thickness of 10 μm or less, and has optical characteristics represented by a single transmittance T and a polarization degree P, which are represented by the following formula P>−(100.929T−42.4). -1) x 100 (where T <42.3), or
It is configured to satisfy the condition of P≧99.9 (where T≧42.3),
Formation of the transparent resin layer and the pressure-sensitive adhesive layer,
A step (1) of applying a coating liquid containing a resin component or a curable component capable of forming a resin layer on the side of the polarizer of the one-sided protective polarizing film while conveying the one-sided protective polarizing film; After forming the transparent resin layer having a thickness of less than 3 μm by performing the step (2) of solidifying or curing the coating liquid after the coating step (1),
The pressure-sensitive adhesive layer is obtained by performing the step (3) of forming the pressure-sensitive adhesive layer on the transparent resin layer without winding the obtained one-sided protective polarizing film with the transparent resin layer into a roll. Method for manufacturing a piece of protective polarizing film attached with. After the step (2) and before the step (3), there is a step (4) of measuring the film thickness of the transparent resin layer in a transport line, and the pressure-sensitive adhesive layer according to claim 1. A method for producing a one-sided protective polarizing film. The method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer according to claim 2, wherein the step (4) is performed by an optical interference method using a polarizing element at the tip of the light source. The coating liquid in the step (1) contains a resin component dissolved or dispersed in water, and the transparent resin layer is formed by solidifying in the step (2). A method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer as described above. The method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer according to claim 4, wherein the coating liquid containing the resin component is an aqueous solution containing a polyvinyl alcohol resin. The coating liquid in the step (1) has a viscosity at 25° C. of 1000 mPa·s or less, and the method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer according to claim 1. .. The said polarizer contains 20 weight% or less of boric acid with respect to the polarizer whole quantity, The manufacturing method of the one-sided protective polarizing film with the adhesive layer in any one of Claims 1-6 characterized by the above-mentioned. The separator is laminated|stacked on the said adhesive layer, The manufacturing method of the piece protective polarizing film with an adhesive layer in any one of the Claims 1-7 characterized by the above-mentioned. The method for producing a one-sided protective polarizing film with a pressure-sensitive adhesive layer according to claim 8, wherein the one-sided protective polarizing film with a pressure-sensitive adhesive layer is a wound body.

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