WO2017164064A1

WO2017164064A1 - Method for producing polarizing film protected on one side and equipped with adhesive layer

Info

Publication number: WO2017164064A1
Application number: PCT/JP2017/010679
Authority: WO
Inventors: 友徳上野; 聡司三田; 岸　敦史; 健太郎池嶋; 佑輔茂手木
Original assignee: 日東電工株式会社
Priority date: 2016-03-22
Filing date: 2017-03-16
Publication date: 2017-09-28
Also published as: TWI725142B; CN108780181B; JP6737609B2; JP2017173434A; KR102093814B1; KR20180098352A; CN108780181A; TW201807124A

Abstract

A method for producing a polarizing film protected on one side and equipped with an adhesive layer, by positioning a transparent resin layer and an adhesive layer, in this order, from the polarizer side thereof onto a polarizing film protected on one side as a result of having a protective film on only one surface of the polarizer, which exhibits specific optical properties and has a thickness of 10μm or less, the method involving: forming a transparent resin layer by transporting the polarizing film protected on side, and while doing so, performing a step (1) for coating the polarizer-side of the polarizing film protected on one side with a coating solution that contains a resin component or a curable component capable of forming a resin layer, and also performing a step (2) for solidifying or curing the coating solution after the coating step (1) has been performed; and thereafter, also performing a step (3) for forming an adhesive layer on the transparent resin layer without rolling the obtained polarizing film protected on one side and equipped with the transparent resin layer into a rolled shape. Thus, even when using a thin film protected on one side, it is possible to stably form a transparent resin layer and then an adhesive layer.

Description

Method for producing a single protective polarizing film with an adhesive layer

This invention relates to the manufacturing method of the piece protection polarizing film with an adhesive layer. The single protective polarizing film with the pressure-sensitive adhesive layer obtained by the above production method can form an image display device such as a liquid crystal display device (LCD) or an organic EL display device alone or as an optical film obtained by laminating it.

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

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

When adhering the polarizing film to a liquid crystal cell or the like, an adhesive is usually used. In addition, since the polarizing film can be fixed instantaneously and has a merit such that a drying step is not required to fix the polarizing film, the adhesive is provided in advance as an adhesive layer on one side of the polarizing film. . That is, a polarizing film with an adhesive layer 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 the polarizing film is also required to be thinner. Therefore, thickness reduction is also performed about the polarizer (patent document 1). Moreover, thickness reduction can be performed by providing a protective film only on one side of the polarizer and using a single protective polarizing film not provided with a protective film on the other side. The single-protective polarizing film can be a thin type because the protective film is less than one protective polarizing film provided with protective films on both sides of the polarizer.

On the other hand, since a single-protective polarizing film has insufficient durability due to the thermal shock, a film provided with a protective layer (transparent resin layer) on the polarizer side has been proposed (Patent Documents 2 and 3).

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

In Patent Documents 2 and 3, thinning is achieved by using a single protective polarizing film having a protective film only on one side of the polarizer, and on the other hand, by providing a protective layer, the single protective polarizing film is used. The absorption axis of the polarizer due to changes in the contraction stress of the polarizer in a harsh environment of a penetrating crack in the direction of the absorption axis of the polarizer (thermal shock (for example, a heat shock test in which temperature conditions of −30 ° C. and 80 ° C. are repeated)) Occurrence of cracks in the entire direction) is suppressed. In Patent Documents 2 and 3, it is described that the protective layer (transparent resin layer) can be formed on the single protective polarizing film by using various coating methods for the forming material.

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

However, in the half-protective polarizing film in which the generation of the through cracks is suppressed or the polarizing film with the pressure-sensitive adhesive layer using the same, the optical properties 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-side protective polarizing film or the polarizing film with an adhesive layer using the same (including the case where a load due to convex folding is applied to the polarizer side), It was found that a very fine slit (hereinafter also referred to as nano slit) is generated in the absorption axis direction of the polarizer. It was also found that the nano slits occur regardless of the size of the polarizing film. Furthermore, it was also found that the nano slit does not occur when both protective polarizing films having protective films on both sides of the polarizer are used. In addition, when a through crack occurs in the polarizer, the stress around the through crack is released, so the through crack does not occur adjacently. I found it to happen. Moreover, although the penetration crack has the progressive property extended in the absorption-axis direction of the polarizer in which the crack generate | occur | produced, it turned out that a nano slit does not have the said progressive property. As described above, the nano slit is a new problem that occurs when the polarizer is thin and the optical characteristics are controlled within a predetermined range in the single-protective polarizing film in which the generation of through cracks is suppressed. It has been found that this is a problem caused by a phenomenon different from the above-described through crack.

Moreover, since the nano slit is extremely thin, it cannot be detected under a normal environment. Therefore, even if nanoslits are generated in the polarizer, it is difficult to confirm the defects due to light leakage of the one-side protective polarizing film and the polarizing film with the pressure-sensitive adhesive layer using it. That is, usually, the piece-protecting polarizing film is produced in the form of a long film and automatically inspected for defects by optical inspection, but it is difficult to detect nanoslits as defects by this defect inspection. The defect caused by the nano slit is that the nano slit spreads in the width direction when the single protective polarizing film or the polarizing film with the adhesive layer is bonded to the glass substrate of the image display panel and placed in a heating environment. It was also found that detection is possible (for example, the presence or absence of light leakage).

Therefore, it is desirable to suppress not only the through cracks but also the generation of nano slits in the single-protective polarizing film having a polarizer thickness of 10 μm or less or the polarizing film with an adhesive layer using the same.

However, in the case of using a thin piece protective polarizing film, after forming the transparent resin layer from the coating liquid of the protective layer (transparent resin layer), for example, the transparency is controlled to a predetermined film thickness by promoting curing. In order to obtain the resin layer, the piece protective polarizing film with a transparent resin layer is once wound up in a roll shape, and the wound piece protective polarizing film with the transparent resin layer is unrolled again, and then the pressure-sensitive adhesive layer. If it is going to shift to the formation process of a process, when feeding out the piece protection polarizing film with a transparent resin layer, stress may be applied to a polarizer locally by blocking (adhesion of the films wound up). Therefore, the roll-shaped product of the piece-protecting polarizing film with a transparent resin layer obtained has increased the risk of occurrence of nanoslits, and has been difficult to feed to the next step. On the other hand, after forming the transparent resin layer, if the surface protective film is affixed on the transparent resin layer and wound, blocking due to the transparent resin layer can be prevented, but when the surface protective film is peeled off, the polarizer is removed. Since stress is applied locally, the risk of nanoslits increases.

The present invention is a pressure-sensitive adhesive that can stably form a transparent resin layer and then a pressure-sensitive adhesive layer and suppress the generation of nano-slits even when a thin pallet protective film is used. It aims at providing the manufacturing method of the piece protection polarizing film with an agent layer.

As a result of intensive studies, the present inventors have found that the above problem can be solved by the following method for producing a piece-protecting polarizing film with an adhesive layer, and have reached the present invention.

That is, the present invention is a method for producing a single 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 single 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 properties represented by the following formula P> − (10 ^{0.929T-42. 4} -1) × 100 (however, T <42.3), or,
P ≧ 99.9 (provided that T ≧ 42.3) is satisfied,
Formation of the transparent resin layer and the pressure-sensitive adhesive layer,
(1) applying a coating liquid containing a curable component capable of constituting a resin component or a resin layer on the polarizer side of the piece protective polarizing film while conveying the piece protective polarizing film; After forming the transparent resin layer by applying the step (2) of solidifying or curing the coating solution after the coating step (1),
The pressure-sensitive adhesive layer is characterized by performing the step (3) of forming a pressure-sensitive adhesive layer on the transparent resin layer without winding the obtained piece-protecting polarizing film with a transparent resin layer into a roll. The present invention relates to a method for producing an attached piece protective polarizing film.

In the method for producing a single protective polarizing film with an adhesive layer, after the step (2), before the step (3), a step (4) of measuring the film thickness of the transparent resin layer in a transport line. 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 manufacturing method of the said piece protection polarizing film with an adhesive layer, by solidifying in a process (2) using what contains the resin component melt | dissolved or disperse | distributed in water as a coating liquid in the said process (1). A transparent resin layer can be formed. The coating solution containing the resin component is preferably an aqueous solution containing a polyvinyl alcohol-based resin.

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

In the method for producing a piece 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 piece protective polarizing film with an adhesive layer, the adhesive layer can be used even if a separator is laminated. The piece protection polarizing film with the adhesive layer provided with the separator can be obtained as a wound body.

The piece 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 thinned. In addition, since 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 than in the case where the thickness of the polarizer is large, generation of a through crack can be suppressed.

On the other hand, a thin polarizer having predetermined optical characteristics is likely to generate nano slits in the polarizer. The nano slit is a process for producing a polarizing film with a pressure-sensitive adhesive layer in which a pressure-sensitive adhesive layer is provided on the piece-protecting polarizing film, and various steps after producing the polarizing film with a pressure-sensitive adhesive layer. It is considered to occur when a mechanical shock is applied to the polarizing film with the agent layer, and is assumed to be generated by a mechanism different from the through crack generated by the thermal shock. In addition, the defect caused by the nano slit is that the nano slit spreads in the width direction when the one-side protective polarizing film with an adhesive layer is bonded to the glass substrate of the image display panel and then placed in a heating environment. Can be detected (for example, the presence or absence of light leakage).

In the piece protection polarizing film with an adhesive layer obtained by the production method of the present invention, the generation of the nano slits is suppressed by providing a transparent resin layer on the other side of the polarizer (the side having no protection film). can do.

According to the production method of the present invention, after the transparent resin layer is formed by the steps (1) and (2) on the single-sided protective film using a thin polarizer, the obtained single-sided protection with the transparent resin layer is performed. The transparent resin is transferred to the next step (3) without winding the polarizing film once in a roll shape and re-feeding the wound piece-protected polarizing film with the transparent resin layer. An adhesive layer is formed on the layer. Thus, in the manufacturing method of this invention, since it does not have the winding-up process and unwinding process of the piece protection polarizing film with a transparent resin layer, the nano slit resulting from blocking of the piece protection polarizing film with a transparent resin layer Without increasing the risk of occurrence, a piece protective polarizing film with an adhesive layer can be produced continuously and stably.

Moreover, in the manufacturing method of this invention, the process (4) which measures the film thickness of a transparent resin layer about the piece protection polarizing film with a transparent resin layer after the said process (2) and before the said process (3). Can be provided. According to the step (4), the film thickness of the transparent resin layer can be stably measured without winding the piece-protecting polarizing film with the transparent resin layer into a roll, and the transparent resin layer has a predetermined film thickness. Can be managed. 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 the process (4) in the manufacturing method of this invention. It is an example of the conceptual diagram which contrasts the nano slit and penetrating crack which arise in a polarizer.

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

In the coating step (1), the coating liquid 2 'is applied to the transporting piece protective polarizing film 1. The single-protective polarizing film 1 has a protective film 20 only on one side of the polarizer 10, and is represented by the configuration of polarizer 10 / protective film 20. In FIG. 1, the coating liquid 2 ′ is shown in a state of being (directly) coated on the polarizer of the piece protective polarizing film 1. The piece protective polarizing film 1 is usually preferably conveyed at 5 to 50 m / min, and more preferably at 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 a piece protective polarizing film A with a transparent resin layer. Next, the step (3) of forming the pressure-sensitive adhesive layer 3 is applied to the transparent resin layer 2 without winding the piece-protective polarizing film A with the transparent resin layer into a roll, and the piece protection with the pressure-sensitive adhesive layer is performed. A polarizing film B is produced.

Moreover, as shown in FIG. 1, in the manufacturing method of this invention, after giving the said process (3) after the said process (2), the process (4) which measures the film thickness of a transparent resin layer in a conveyance line. ). 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 piece protective polarizing film. The light source 40 is installed so that it may become perpendicular | vertical from the transparent resin layer 2 side of the piece protection polarizing film A with a transparent resin layer. The polarizing element 41 is used between the light source 40 and the piece protective polarizing film A with the transparent resin layer so that the light source 40 and the polarizer 10 of the piece protective polarizing film A with the transparent resin layer are orthogonal to each other. The thickness of the transparent resin layer 2 is measured by an optical interference method.

Although not shown, a separator can be provided on the pressure-sensitive adhesive layer of the piece protective polarizing film B with the pressure-sensitive adhesive layer of the present invention. Moreover, a surface protective film can be provided on the protective film 20 side of the piece protective polarizing film B with an adhesive layer of the present invention. The piece-protecting polarizing film with a pressure-sensitive adhesive layer having at least a separator (further having a surface protective film) can be used as a wound body. For example, the pressure-sensitive adhesive fed out from the wound body and conveyed by the separator Applying to a method of bonding a polarizing film with a layer to the surface of an image display panel via an adhesive layer (also referred to as “roll-to-panel method”. Typically, Japanese Patent No. 440643), The image display device can be manufactured continuously.

FIG. 3 is a conceptual diagram comparing the nano slit a and the through crack b generated in the polarizer. FIG. 3A shows a nano slit a generated in the polarizer 10, and FIG. 3B shows a through crack b generated in the polarizer 10. The nano slit a is generated by mechanical impact and is partially generated in the absorption axis direction of the polarizer 10. The nano slit a cannot be confirmed at the beginning, but it is 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 nano slit a does not have a progressive property extending in the absorption axis direction of the polarizer. Moreover, it is thought that the said nano slit a arises irrespective of the size of a polarizing film. The nano slits a may occur not only independently but also adjacent to each other. On the other hand, the through crack b is generated by a thermal shock (for example, a heat shock test). The through crack has a process of extending in the absorption axis direction of the polarizer where the crack has occurred. When the through crack b is generated, the peripheral stress is released, so that the through crack does not occur adjacently.

<Step (1)>
≪Single protective polarizing film≫
The said piece protection polarizing film uses what has a protection film only in the single side | surface of a thin polarizer. Moreover, the piece protective polarizing film preferably has a thickness (total thickness) of 60 μm or less. Even in such a thin protective film, the transparent resin layer having a stable thickness can be formed according to the production method of the present invention. The piece protective polarizing film may further have a thickness of 55 μm or less. On the other hand, from the viewpoint of transportability, the thickness of the thin protective film is preferably 20 μm or more, and more preferably 25 μm or more.

≪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 reducing the thickness and preventing the occurrence of through cracks. On the other hand, the thickness of the polarizer is preferably 2 μm or more, and more preferably 3 μm or more. Such a thin polarizer has less thickness unevenness, excellent visibility, and less dimensional change, and therefore excellent durability against thermal shock.

A polarizer using a polyvinyl alcohol resin is used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable.

A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol in an aqueous iodine solution and stretching it 3 to 7 times the original length. If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched even in an aqueous solution such as 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 boric acid content contained in the polarizer is preferably 20% by weight or less, more preferably 18% by weight or less, more preferably 18% by weight or less, from the viewpoint of suppressing the occurrence of through cracks and suppressing the expansion. It is preferably 16% by weight or less. On the other hand, from the viewpoint of the stretching stability and optical durability of the polarizer, the boric acid content with respect to the total amount of the polarizer is preferably 10% by weight or more, and more preferably 12% by weight or more.

As a thin polarizer, typically, Japanese Patent No. 4751486, Japanese Patent No. 4751481, Japanese Patent No. 4815544, Japanese Patent No. 5048120, International Publication No. 2014/0777599, International Publication No. The thin polarizer described in the publication 2014/077636 pamphlet etc. or the thin polarizer obtained from the manufacturing method described in these can be mentioned.

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

As the thin polarizer, among the production methods including the step of stretching in the state of a laminate and the step of dyeing, Patent No. 4751486, Patent, in that it can be stretched at a high magnification and the polarization performance can be improved. What is obtained by the manufacturing method including the process of extending | stretching in a boric-acid aqueous solution as described in the 4751481 specification and the patent 4815544 specification is preferable, and it describes especially in the patent 4751481 specification and the patent 4815544 specification. What is obtained by the manufacturing method including the process of extending | stretching in the air auxiliary before extending | stretching in the boric-acid aqueous solution which has this 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 laminated state and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching by being supported by the stretching resin substrate.

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

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

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

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

The thickness of the protective film can be determined as appropriate, but in general, it is preferably 2 to 200 μm, more preferably 3 to 100 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. Is preferred. In particular, in order to adjust the thickness (total thickness) of the single protective polarizing film to 60 μm or less, the thickness of the protective film (when the film is formed in advance) is preferably 15 to less than 60 μm from the viewpoint of transportability, Furthermore, 20 to 55 μm is preferable. On the other hand, the thickness of the protective film (when formed by coating and curing) is preferably from 3 to 50 μm, more preferably from 5 to 40 μm, from the viewpoint of transportability. The protective film may be used in a plurality of layers or in a plurality of layers.

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

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

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

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

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

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

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

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

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

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

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

≪Coating liquid≫
The coating liquid contains a curable component capable of constituting a resin component or a resin layer. A transparent resin layer is formed by the coating liquid.

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

The coating of the coating liquid on the piece protective polarizing film (polarizer side) is preferably performed 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, and more preferably 0.7 μm or more. On the other hand, when the transparent resin layer becomes too thick, the optical reliability and water resistance are lowered. Therefore, the thickness of the transparent resin layer is preferably 3 μm or less, more preferably less than 3 μm, and further 2 μm or less. Is preferred.

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

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

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

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

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

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

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

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

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

The 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 it as an aqueous solution using water as a solvent. The concentration of the polyvinyl alcohol-based resin in the forming material (for example, an aqueous solution) is not particularly limited, but is 0.1 to 15% by weight, preferably 0.5%, in consideration of coating properties and storage stability. ~ 10% by weight.

In the coating liquid (for example, an aqueous solution), examples of the additive 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. Furthermore, coupling agents such as silane coupling agents and titanium coupling agents, various tackifiers, ultraviolet absorbers, antioxidants, heat stabilizers, hydrolysis stabilizers, and other stabilizers can be added.

The application of the coating solution is preferably performed so that the thickness after drying is 0.2 μm or more. The application operation is not particularly limited, and any appropriate method can be adopted. For example, 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 can be adopted.

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

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

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

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

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

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

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

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

Examples of the monofunctional radical polymerizable compound include lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, Examples thereof include vinyl monomers having a nitrogen-containing heterocyclic ring such as vinyl pyrrole, vinyl imidazole, vinyl oxazole and vinyl morpholine.

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

≪Polyfunctional radical polymerizable compound≫
Examples of the bifunctional or higher polyfunctional radical polymerizable compound include tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9 -Nonanediol di (meth) acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di (meth) acrylate, bisphenol A di (meth) acrylate, bisphenol A ethylene oxide adduct di (meth) ) Acrylate, bisphenol A propylene oxide adduct di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, neopentyl glycol di (meth) acrylate, tricyclodecane dimethanol di (meth) Acryte, cyclic trimethylolpropane formal (meth) acrylate, dioxane glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta Esterified products of (meth) acrylic acid and polyhydric alcohols such as (meth) acrylate, dipentaerythritol hexa (meth) acrylate, EO-modified diglycerin tetra (meth) acrylate, 9,9-bis [4- (2- (Meth) acryloyloxyethoxy) phenyl] fluorene. Specific examples include Aronix M-220, M-306 (manufactured by Toagosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DCP- A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer) and the like. Moreover, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various (meth) acrylate monomers, and the like are included as necessary.

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

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

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

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

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

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

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

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

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

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

Wherein R ³ , R ⁴ and R ⁵ represent —H, —CH ₃ , —CH ₂ CH ₃ , —iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different. It is preferable to use it. As the compound represented by the general formula (2), 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (trade name: IRGACURE907 manufacturer: BASF) which is also a commercial product is suitable. Can be used. In addition, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (trade name: IRGACURE369 manufacturer: BASF), 2- (dimethylamino) -2-[(4-methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (trade name: IRGACURE379 manufacturer: BASF) is preferred because of its high sensitivity.

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

Examples of the thermal polymerization initiator include lauroyl peroxide (10 hour half-life temperature: 64 ° C.), benzoyl peroxide (10 hour half-life temperature: 73 ° C.), 1,1-bis (t-butylperoxy) -3. , 3,5-trimethylcyclohexane (10-hour half-life temperature: 90 ° C.), di (2-ethylhexyl) peroxydicarbonate (10-hour half-life temperature: 49 ° C.), di (4-t-butylcyclohexyl) Peroxydicarbonate, di-sec-butylperoxydicarbonate (10-hour half-life temperature: 51 ° C.), t-butyl peroxyneodecanoate (10-hour half-life temperature: 48 ° C.), t-hexyl peroxy Pivalate, t-butylperoxypivalate, dilauroyl peroxide (10 hour half-life temperature: 64 ° C.), di-n-

octanoyl peroxide

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

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

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

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

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

The 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 coating methods include reverse coaters, gravure coaters (direct, reverse and offset), bar reverse coaters, roll coaters, die coaters, bar coaters, rod coaters and the like. In addition, for coating, a method such as a dapping method can be appropriately used.

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

In forming the transparent resin layer, after coating 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 obtained by dissolving or dispersing the resin component in a solvent, and is used as, for example, an aqueous solution, an aqueous dispersion, or a solvent solution. The solidification means forming a resin layer by removing a solvent from the coating solution. 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 solidified similarly.

The drying temperature is usually preferably 60 to 200 ° C., 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 constituting the 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 constitute the resin can be used in a solventless system as long as the curable component exhibits a coating liquid. Moreover, the said coating liquid can use the solution which melt | dissolved the said sclerosing | hardenable component in the solvent. The curable component can also be used as a solution when presenting a coating solution. The solvent can be appropriately selected according to the curable component to be used. For example, when an acrylic monomer that forms an acrylic resin is used as the curable component, or when an epoxy monomer that forms an epoxy resin is used, the coating liquid containing the curable component is irradiated with active energy rays ( Curing by ultraviolet irradiation or the like can be performed.

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

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

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

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

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

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

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

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

<Step (3)>
Next, the step (3) of forming a pressure-sensitive adhesive layer is applied to the transparent resin layer without winding the piece-protecting polarizing film with a transparent resin layer obtained in the step (2) into a roll, and the pressure-sensitive adhesive A polarizing film with a layer can be produced. A separator can be provided in the pressure-sensitive adhesive layer of the polarizing film with the pressure-sensitive adhesive layer.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The optical film obtained by laminating the above optical layer on the single protective polarizing film with the pressure-sensitive adhesive layer of the present invention can be formed by a method of laminating separately separately in the manufacturing process of a liquid crystal display device or the like. Thus, the optical film is excellent in quality stability and assembly work, and has the advantage of improving the manufacturing process of the liquid crystal display device and the like. For the lamination, an appropriate adhesive means such as a pressure-sensitive adhesive layer can be used. When adhering the above-mentioned piece protective polarizing film with the pressure-sensitive adhesive layer and other optical films, their optical axes can be arranged at an appropriate angle depending on the target retardation characteristics and the like.

The piece protective polarizing film or optical film with an adhesive layer of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell and a single protective polarizing film or optical film with an adhesive layer, and an illumination system as necessary, and incorporating a drive circuit. However, in this invention, there is no limitation in particular except the point which uses the piece protection polarizing film or optical film with an adhesive layer of this invention by this invention, According to the former, it can apply. As the liquid crystal cell, an arbitrary type such as an IPS type or a VA type can be used, but is particularly suitable for the IPS type.

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

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

<Single protective polarizing film>
(Production of polarizer)
One side of an amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and Tg of 75 ° C. is subjected to corona treatment. 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 9: 1 ratio of the trade name “Gosefimer Z200”) was applied and dried at 25 ° C. to form a PVA-based resin layer having a thickness of 11 μm, thereby preparing a laminate.
The obtained laminate was uniaxially stretched in the longitudinal direction (longitudinal direction) 2.0 times between rolls having different peripheral speeds in an oven at 120 ° C. (air-assisted stretching process).
Next, the laminate was immersed in an insolubilization bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Subsequently, it 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 parts by weight of iodine was blended with 100 parts by weight of water, and immersed in an aqueous iodine solution obtained by blending 1.0 part by weight of potassium iodide (dyeing treatment). .
Subsequently, it was immersed for 30 seconds in a crosslinking bath having a liquid temperature of 30 ° C. (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water). (Crosslinking treatment).
Thereafter, the laminate was immersed in a boric acid aqueous solution (an aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70 ° C. However, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) so that the total stretching ratio was 5.5 times (in-water stretching treatment).
Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 30 ° C. (cleaning treatment).
As a result, 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 with a thickness of 40 μm was subjected to corona treatment on the easy adhesion treated surface.

(Production of adhesive to be applied to protective film)
An ultraviolet curable adhesive was prepared by mixing 40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO), and 3 parts by weight of a photoinitiator “IRGACURE 819” (manufactured by BASF).

(Production of single-protective polarizing film)
After applying the UV curable adhesive to 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 bonded, and then the active energy As a line, ultraviolet rays were irradiated to cure the adhesive. Ultraviolet irradiation is performed using a gallium-encapsulated metal halide lamp, an irradiation device: Fusion UV Systems, Inc. Light HAMMER 10, Inc., bulb: V bulb, peak illuminance: 1600 mW / cm ² , integrated irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm) ), And the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Subsequently, the amorphous PET base material was peeled off, and a piece protective polarizing film (total thickness: 45.5 μm) using a thin polarizer was produced. The optical properties of the obtained piece-protecting polarizing film were a single transmittance of 42.8% and a degree of polarization of 99.99%.

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

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

(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 inlet tube, and a condenser. Furthermore, 0.1 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged with ethyl acetate to 100 parts of the monomer mixture (solid content), and nitrogen gas was introduced while gently stirring. Then, the temperature of the liquid in the flask was kept at around 60 ° C., and a polymerization reaction was carried out for 7 hours. Then, ethyl acetate was added to the resulting reaction solution to prepare a solution of an acrylic polymer having a weight average molecular weight of 1,400,000 adjusted to a solid content concentration of 30%.

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

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

Example 1
<Preparation of a single protective polarizing film with a transparent resin layer>
A transparent resin layer forming material (coating liquid) is applied to the surface of the polarizer (the surface of the polarizer on which no protective film is provided) of the above piece-protecting polarizing film conveyed at 20 m / min. Was applied using a gravure coater to a thickness of 1 μm after drying, and then dried with hot air at 85 ° C. for 30 seconds to produce a piece protective polarizing film with a transparent resin layer.

<Preparation of polarizing film with adhesive layer>
Subsequently, without rolling up the piece protective polarizing film with a transparent resin layer obtained above in a roll shape (specifically, after 18 seconds), the release sheet (separator) is placed on the transparent resin layer. The pressure-sensitive adhesive layer formed on the release-treated surface was bonded to produce a polarizing film with a pressure-sensitive adhesive layer. Then, the polarizing film with an adhesive layer was wound up to make a roll.

In an example, after manufacturing a piece protection polarizing film with a transparent resin layer, before a pressure sensitive adhesive layer is pasted, a device (a device for measuring a film thickness: an optical spectrometer: manufactured by Ocean Optics) The film thickness of the transparent resin layer was measured using USB2000 +, light source: HL-2000, optical fiber: ZFQ-12796 (200 μm reflective fiber), polarizing element: the piece 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 examples was 1.0 ± 0.1 μm and was stable.

Comparative Example 1
A piece-protecting polarizing film with a transparent resin layer produced in the same manner as in the example was wound up to obtain a roll. Then, although it tried to pay out from the roll-shaped object of the piece protection polarizing film with a transparent resin layer, since the roll-shaped object had blocking, it was not able to pay out.

Comparative Example 2
A piece-protected polarizing film with a transparent resin layer produced in the same manner as in Example was wound up with a separator to obtain a roll. Thereafter, the roll-out of the piece-protecting polarizing film with a transparent resin layer was tried to be fed out, but the adhesiveness between the transparent resin layer and the separator was weak, and rupture occurred immediately after the conveyance due to being caught during the conveyance.

In the examples, the risk of occurrence of nano slits was low, while in the comparative example, the risk of occurrence of nano slits was high.

DESCRIPTION OF SYMBOLS 1 Piece protective polarizing film 10 Polarizer 20 Protective film 2 'Coating liquid 2 Transparent resin layer 3 Adhesive layer 40 Light source 41 Polarizer A Single piece protective polarizing film with a transparent resin layer B Single piece protective polarizing film with an adhesive layer

Claims

A method for producing a single 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 single protective polarizing film 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 properties represented by the following formula P> − (10 0.929T-42. 4 -1) × 100 (however, T <42.3), or,
P ≧ 99.9 (provided that T ≧ 42.3) is satisfied,
Formation of the transparent resin layer and the pressure-sensitive adhesive layer,
(1) applying a coating liquid containing a curable component capable of constituting a resin component or a resin layer on the polarizer side of the piece protective polarizing film while conveying the piece protective polarizing film; After forming the transparent resin layer by applying the step (2) of solidifying or curing the coating solution after the coating step (1),
The pressure-sensitive adhesive layer is characterized by performing the step (3) of forming a pressure-sensitive adhesive layer on the transparent resin layer without winding the obtained piece-protecting polarizing film with a transparent resin layer into a roll. A manufacturing method of the attached piece protection polarizing film.
The adhesive layer according to claim 1, further comprising a step (4) of measuring the film thickness of the transparent resin layer in the transport line after the step (2) and before the step (3). Of manufacturing a single piece protective polarizing film.
3. The method for producing a piece protective polarizing film with an 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 a light source.
The coating liquid in the step (1) contains a resin component dissolved or dispersed in water, and a transparent resin layer is formed by solidifying in the step (2). The manufacturing method of the piece protection polarizing film with an adhesive layer of description.
The method for producing a piece protective polarizing film with an adhesive layer according to claim 4, wherein the coating liquid containing the resin component is an aqueous solution containing a polyvinyl alcohol-based resin.
The method for producing a piece protective polarizing film with an adhesive layer according to any one of claims 1 to 5, wherein the coating liquid in the step (1) has a viscosity at 25 ° C of 1000 mPa · s or less. .
The method for producing a piece protective polarizing film with an adhesive layer according to any one of claims 1 to 6, wherein the polarizer contains boric acid in an amount of 20% by weight or less based on the total amount of the polarizer.
The method for producing a piece protective polarizing film with an adhesive layer according to any one of claims 1 to 7, wherein a separator is laminated on the adhesive layer.
The method for producing a piece protective polarizing film with an adhesive layer according to claim 8, wherein the piece protective polarizing film with an adhesive layer is used as a wound body.