KR102166983B1 - Method for producing a single protective polarizing film with a transparent resin layer, a method for producing a polarizing film with an adhesive layer, and a method for producing an optical laminate - Google Patents

Abstract

The present invention is a method of manufacturing a single protective polarizing film having a protective film only on one side of the polarizer and a single protective polarizing film with a transparent resin layer having a transparent resin layer provided on the other side of the polarizer of the single protective polarizing film, wherein the polarizer is poly The process of applying a coating liquid containing a resin component or a curable component capable of constituting a transparent resin layer to the polarizer and solidifying the obtained coating film in the transparent resin layer, which contains a vinyl alcohol-based resin and has a thickness of 10 μm or less. Or formed by a process of curing, and in the coating process of the coating solution, the polarizer has an uncoated portion not applied with the coating solution in an area of less than 20 mm from both ends in the width direction to the inside, or the It is characterized in that the coating liquid is applied over the entire width direction of the polarizer. According to the production method of the present invention, the occurrence of curl of the piece protective polarizing film with a transparent resin layer can be suppressed.

Description

Method for producing a single protective polarizing film with a transparent resin layer, a method for producing a polarizing film with an adhesive layer, and a method for producing an optical laminate

The present invention relates to a method for producing a single protective polarizing film with a transparent resin layer. In addition, the present invention relates to a method for producing a polarizing film with a pressure-sensitive adhesive layer in which a pressure-sensitive adhesive layer is formed on the transparent resin layer of the single protective polarizing film with a transparent resin layer, and a method for producing an optical laminate using the polarizing film with the pressure-sensitive adhesive layer. The unprotected polarizing film with a transparent resin layer and the polarizing film with an adhesive layer obtained by the production method of the present invention may be used alone or as an optical laminate obtained by laminating the same as an image display device such as a liquid crystal display device (LCD) or an organic EL display device. Can be formed.

In watches, mobile phones, PDAs, notebook computers, PC monitors, DVD players, and TVs, liquid crystal displays are rapidly expanding the market. A liquid crystal display device visualizes a polarization state by switching of a liquid crystal, and a polarizer is used from the display principle.

As a polarizer, since it has high transmittance and high polarization, for example, an iodine polarizer having a structure in which iodine is adsorbed to a polyvinyl alcohol film and stretched is most commonly used. Such a polarizer has a disadvantage in that the mechanical strength is extremely weak and the polarization function is remarkably deteriorated due to shrinkage due to heat or moisture. Accordingly, the obtained polarizer is immediately bonded to each other via an adhesive-coated protective film and an adhesive, and is used as a polarizing film.

On the other hand, image display devices, such as a liquid crystal display, are progressing thinning, and thinning is also required for a polarizing film. Therefore, thinning is also achieved for the polarizer. In addition, thinning can be achieved by using a protective film provided only on one side of the polarizer and a non-protective polarizing film on the other side. Such a single protective polarizing film can achieve a thinner shape because it has one less protective film than a positive polarizing film provided with a protective film on both sides of a polarizer.

On the other hand, since the single protective polarizing film has insufficient durability due to thermal shock, it has been proposed that a protective layer (transparent resin layer) is provided on the side of the polarizer (see, for example, Patent Documents 1 and 2).

In addition, as a method of manufacturing a polarizing laminated film, a resin layer was formed by providing an uncoated portion to which a resin solution was not applied in an area of 0.5 cm or more from both ends in the width direction of the base film to the inside, and from the obtained laminated film. A method of manufacturing a polarizing laminated film by cutting and removing the uncoated portion and then performing stretching treatment and dyeing treatment has been proposed (see, for example, Patent Document 3).

Patent Document 1: Japanese Laid-Open Patent Publication No. 2010-009027 Patent document 2: Japanese Laid-Open Patent Publication No. 2013-160775 Patent Document 3: Japanese Laid-Open Patent Publication No. 2011-212550

In Patent Documents 1 and 2, a protective layer (transparent resin layer) is formed on the single protective polarizing film, but such a polarizing film is often curled, and when conveying the obtained polarizing film, the polarizing film ends There are cases where a break occurs, a break occurs due to the break, or a problem such as wrinkle occurs when stacking on another member.

In the manufacturing method of the polarizing laminated film of Patent Document 3, by forming an uncoated portion of 0.5 cm or more and removing the uncoated portion, the resulting film is prevented from warping. In the method of Patent Document 3, a process of removing the uncoated portion was required, and the manufacturing process was complicated.

Therefore, in this invention, it aims at providing the manufacturing method of the piece protective polarizing film with a transparent resin layer which can suppress the occurrence of curl. In addition, it is an object of the present invention to provide a method for producing a polarizing film with an adhesive layer and a method for producing an optical laminate.

As a result of intensive examination, the inventors of the present invention discovered that the above problem could be solved by the method for producing a single protective polarizing film with a transparent resin layer described below, and reached the present invention.

That is, the present invention is a method for producing a single protective polarizing film having a protective film only on one side of the polarizer and a single protective polarizing film with a transparent resin layer having a transparent resin layer provided on the other surface of the polarizer of the single protective polarizing film

The polarizer includes a polyvinyl alcohol-based resin, and has a thickness of 10 μm or less,

The transparent resin layer is formed by a process of applying a coating liquid containing a resin component or a curable component capable of constituting the transparent resin layer to the polarizer and a process of solidifying or curing the obtained coating film,

In the coating process of the coating solution, the polarizer has an uncoated portion not coated with the coating solution in an area of less than 20 mm from both ends in the width direction of the polarizer, or the coating solution over the entire width direction of the polarizer It relates to a method for producing a single protective polarizing film with a transparent resin layer, characterized in that applying.

It is preferable that the coating solution is applied by applying the coating solution over the entire width direction of the polarizer.

It is preferable that the width of the polarizer is 1,100 to 2,000 mm.

It is preferable that the transparent resin layer is formed by solidifying the coating film, and the solidification is performed by drying.

It is preferable that the drying temperature is 120°C or less.

It is preferable that the drying time is within 180 seconds.

It is preferable that the said coating liquid is a coating liquid containing a resin component, and the said resin component is a polyvinyl alcohol-type resin.

Further, the present invention relates to a method for producing a polarizing film with a pressure-sensitive adhesive layer, comprising a step of forming a pressure-sensitive adhesive layer on the transparent resin layer of the piece protective polarizing film with a transparent resin layer obtained by the above-described production method.

In addition, the present invention relates to a method for manufacturing an optical laminate comprising a step of bonding the polarizing film with an adhesive layer obtained by the above manufacturing method to an optical member via the pressure-sensitive adhesive layer without winding up. About.

In the method for producing a single protective polarizing film with a transparent resin layer of the present invention, when a coating liquid containing a resin component or a curable component capable of constituting a transparent resin layer is applied to a polarizer, from both ends in the width direction of the polarizer to the inside. Each has an uncoated portion in an area of less than 20 mm, to which the coating solution is not applied, or the coating solution is applied over the entire width direction of the polarizer, thereby suppressing the occurrence of curling of the unprotected polarizing film with the obtained transparent resin layer. can do. Further, the polarizing film with an adhesive layer in which an adhesive layer is provided on the transparent resin layer of the single protective polarizing film with the transparent resin layer is also suppressed from occurrence of curl. Accordingly, the single protective polarizing film with a transparent resin layer or the polarizing film with an adhesive layer obtained by the production method of the present invention can be laminated on an optical member used for an image display device or the like without being wound up on a roll or the like after production.

1 is an example of a schematic cross-sectional view of a piece protective polarizing film with a transparent resin layer obtained by the production method of the present invention.
2 is an example of a schematic cross-sectional view of a piece protective polarizing film with a transparent resin layer obtained by the production method of the present invention.

1. Method for producing a single protective polarizing film with a transparent resin layer

The manufacturing method of the piece protective polarizing film with the transparent resin layer of this invention,

A single protective polarizing film having a protective film on only one side of the polarizer and a single protective polarizing film with a transparent resin layer having a transparent resin layer provided on the other side of the polarizer of the single protective polarizing film can be prepared,

The polarizer includes a polyvinyl alcohol-based resin, and has a thickness of 10 μm or less,

The transparent resin layer is formed by a process of applying a coating liquid containing a resin component or a curable component capable of constituting the transparent resin layer to the polarizer and a process of solidifying or curing the obtained coating film,

In the coating process of the coating solution, the polarizer has an uncoated portion not coated with the coating solution in an area of less than 20 mm from both ends in the width direction of the polarizer, or the coating solution over the entire width direction of the polarizer It is characterized in that to apply.

A single protective polarizing film with a transparent resin layer obtained by the production method of the present invention will be described with reference to FIGS. 1 and 2. However, the present invention is not limited to these drawings.

The single protective polarizing film 3 used in the present invention has the protective film 2 only on one side of the polarizer 1. The polarizer 1 and the protective film 2 may be laminated through an intervening layer (not shown) such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer). The manufacturing method of the present invention is to form a transparent resin layer 4 on the side (the other side) that does not have the protective film 2 of the polarizer 1 of the single protective polarizing film 3 to form a single protective polarization with a transparent resin layer. It is a method of manufacturing the film 10.

The formation of the transparent resin layer 4 includes a step of applying a coating solution containing a resin component or a curable component capable of constituting the transparent resin layer 4 to the polarizer 1 and a step of solidifying or curing the obtained coating film. Formed by In the coating process of the coating solution, as shown in Fig. 1, the polarizer 1 is not coated in an area of less than 20 mm from both ends of the polarizer 1 in the width direction (direction A in the drawing). It has a part 5 or, as shown in FIG. 2, is characterized by applying a coating liquid over the entire width direction of the polarizer 1 (no uncoated part). By applying in this way, it is possible to suppress the occurrence of curl of the obtained piece protective polarizing film 10 with a transparent resin layer, and after manufacture, it can be bonded to an optical member used for an image display device or the like without being wound up on a roll or the like. In addition, the width direction of the polarizer 1 here means a direction orthogonal to the extending direction (transport direction) of the polarizer 1.

Further, in the coating, when the uncoated portion is provided, the uncoated portion is an area of less than 20 mm, preferably 15 mm or less, and preferably 10 mm or less from both ends in the width direction of the polarizer. More preferable. It is preferable from the point of being able to suppress the curling of the piece protective polarizing film with a transparent resin layer obtained by making the uncoated part fall within the said range. The lower limit of the area of the uncoated portion is not particularly limited, and the smaller the value is, the more preferable, and a method of applying the coating liquid over the entire width direction of the polarizer, that is, not having an uncoated portion is particularly preferable.

Further, in the coating, when the uncoated portion is provided, the uncoated portion is preferably 5% or less of the width of the polarizer from both ends in the width direction of the polarizer to the inside, and 3 with respect to the width of the polarizer. It is more preferable that it is a region less than %, and it is more preferable that it is a region of 2% or less with respect to the width of a polarizer. It is preferable from the point of being able to suppress the curling of the piece protective polarizing film with a transparent resin layer obtained by making the uncoated part fall within the said range. The lower limit of the area of the uncoated portion is not particularly limited, and the smaller the value is, the more preferable, and a method of applying the coating solution over the entire width direction of the polarizer, that is, 0% with respect to the width of the polarizer (the uncoated portion is Not having) is particularly preferred.

Hereinafter, each step of the manufacturing method of the present invention will be described.

1-1. Coating liquid application process

The manufacturing method of the present invention comprises a resin component or a curable component capable of constituting a transparent resin layer on the side (the other side) of the polarizer 1 of the single protective polarizing film 3 that does not have the protective film 2 It includes a step of applying a coating liquid. The application method is as described above.

(1) single protection polarizing film

(1-1) 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 even more preferably 6 µm or less. On the other hand, the thickness of the polarizer is preferably 2 µm or more, and more preferably 3 µm or more. Since such a thin polarizer has little thickness unevenness, excellent visibility, and little dimensional change, it has excellent durability against thermal shock.

As the polarizer 1, a polyvinyl alcohol-based resin is used. As the polarizer 1, for example, in a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene/vinyl acetate copolymer-based partial saponification film, the dichroic property of iodine or dichroic dye. And polyene-based oriented films such as those obtained by adsorbing a substance and uniaxially stretched, and a dehydration treatment product of polyvinyl alcohol or a dehydrochloric acid treatment product of polyvinyl chloride. Among these, a polarizer made of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable.

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

It is preferable from the viewpoint of stretching stability and optical durability that the polarizer 1 contains boric acid. In addition, the content of boric acid contained in the polarizer 1 is preferably 25% by weight or less, more preferably 20% by weight or less, more preferably 20% by weight or less, with respect to the total amount of the polarizer from the viewpoint of suppressing the occurrence of penetration cracks and nano slits and suppressing expansion. % Or less is more preferable, and 16 weight% or less is particularly preferable. When the content of boric acid in the polarizer 1 exceeds 20% by weight, even when the thickness of the polarizer 1 is controlled to be 10 μm or less, the shrinkage stress of the polarizer 1 increases, and penetration cracks are liable to occur. Not desirable. On the other hand, from the viewpoint of stretch stability and optical durability of the polarizer 1, 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.

Typical examples of the thin polarizer include Japanese Patent No. 4771486, Japanese Patent No. 44751481, Japanese Patent No. 4815544, Japanese Patent No. 5048120, International Publication No. 2014/077599, International Publication No. The thin polarizer described in Unexamined Publication No. 2014/077636 pamphlets or the like or the thin polarizer obtained from the manufacturing method described therein may be mentioned.

The polarizer 1 has an optical characteristic represented by the single transmittance (T) and polarization degree (P) in the following formula: P>-(10 ^0.929T-42.4 -1)×100 (however, T<42.3) or P≥ It is preferable to be configured to satisfy the condition of 99.9 (however, T≥42.3). The polarizer configured to satisfy the above condition has a performance required as a display for a liquid crystal TV using a large display element, in a sense. Specifically, the contrast ratio is 1000:1 or more and the maximum luminance is 500 cd/m ² or more. As another application, for example, it is attached to the viewer side of an organic EL display device.

As the thin polarizer, it is possible to stretch at a high magnification and improve polarization performance among the manufacturing methods including the step of stretching and dyeing in the state of a layered body, so that the specification of Japanese Patent No. 4771486 and Japanese Patent No. 44751481 It is preferable that it is obtained by a manufacturing method including a step of stretching in an aqueous boric acid solution as described in the specification, Japanese Patent No. 4815544, and in particular, it is described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544. It is preferably obtained by a manufacturing method including a step of auxiliary air stretching before stretching in an aqueous boric acid solution. These thin polarizers can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin layer and a resin substrate for stretching in the state of a laminate and a step of dyeing. With this manufacturing method, even if the polyvinyl alcohol-based resin layer is thin, it is supported by the resin substrate for stretching, so that it is possible to stretch without problems such as fracture due to stretching.

(1-2) protective film

The material constituting the protective film 2 is preferably those having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropic properties, and the like. 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, polystyrene or acrylonitrile-styrene copolymer (AS Styrene-based polymers such as resin), and polycarbonate-based polymers. In addition, polyethylene, polypropylene, polyolefins having a cyclo-based or norbornene structure, polyolefin-based polymers such as ethylene-propylene copolymers, vinyl chloride-based polymers, amide-based polymers such as nylon or aromatic polyamide, imide-based polymers, and sulfone-based Polymer, polyethersulfone polymer, polyetheretherketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy Polymers or mixtures of these polymers are also examples of polymers that form the protective film.

Moreover, one or more types of arbitrary suitable additives may be contained in the protective film 2. Examples of the additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. 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 the content of the thermoplastic resin in the protective film is less than 50% by mass, there is a fear that the high transparency inherent in the thermoplastic resin may not be sufficiently expressed.

As the protective film 2, a retardation film, a brightness improving film, a diffusion film, or 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 in the thickness direction of 80 nm or more. The front retardation is usually controlled in the range of 40 to 200 nm, and the thickness direction retardation is typically controlled in the range of 80 to 300 nm. When using a retardation film as a protective film, since the said retardation film also functions as a polarizer protective film, thickness reduction can be aimed at.

As the retardation film, a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film is exemplified. The stretching temperature, stretching ratio, and the like are appropriately set according to the retardation value, the material of the film, and the thickness.

The thickness of the protective film 2 can be appropriately determined, but in general, it is preferably 3 to 200 µm from the viewpoint of workability such as strength and handling, thin layer properties, etc., and further 3 to It is preferably 100 μm. In particular, the thickness of the protective film (when a film is formed in advance) is preferably 10 to 60 µm from the viewpoint of transportability, and further preferably 10 to 50 µm. On the other hand, the thickness of the protective film (when formed by coating or curing) is preferably 3 to 25 µm, and further preferably 3 to 20 µm from the viewpoint of transportability. The protective film may be used in plural or plural layers.

Functional layers such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer may be provided on the surface of the protective film 2 on which the polarizer 1 is not adhered. In addition, functional layers such as the hard coat layer, anti-reflection layer, anti-sticking layer, diffusion layer or anti-glare layer can be provided on the protective film 2 itself, and are separate from the protective film. It can also be installed.

(1-3) Intervening layer

The protective film 2 and the polarizer 1 may be laminated through an intervening layer such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer). At this time, it is preferable to stack both with an intervening layer without air gap. In addition, the interposition layer of the polarizer 1 and the protective film 2 is not shown in the drawing.

The adhesive layer is formed by the adhesive. The type of adhesive is not particularly limited, and a variety of adhesives can be used. The adhesive layer is not particularly limited as long as it is optically transparent, and various types of adhesives such as water-based, solvent-based, hot-melt-based, and active energy ray-curable type can be used, but water-based adhesives or active energy ray-curable adhesives are preferable. Do.

Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based, and water-based polyesters. The water-based adhesive is usually used as an adhesive made 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 in which curing proceeds by an active energy ray such as an electron beam or an ultraviolet ray (radical curing type, cation curing type), and can be used, for example, in an electron ray curing type or an ultraviolet curing type. As the active energy ray-curable adhesive, for example, a photo radical curable adhesive may be used. When a photo-radical curable active energy ray-curable adhesive is used as an ultraviolet curable adhesive, the adhesive contains a radical polymerizable compound and a photopolymerization initiator.

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

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

In addition, in the lamination of the polarizer 1 and the protective film 2, an easily adhesive layer can be provided between the protective film and the adhesive layer. The easily adhesive layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone system, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins may be used alone or in combination of two or more. Further, other additives may be added to the formation of the easily adhesive layer. Specifically, stabilizers, such as a tackifier, an ultraviolet absorber, an antioxidant, and a heat-resistant stabilizer, etc. are mentioned.

The easily adhesive layer is usually provided in advance on the protective film, and the easily adhesive layer side of the protective film and the polarizer are laminated by an adhesive layer. The formation of the easily-adhesive layer is performed by coating and drying the easily-adhesive layer-forming material on a protective film by a known technique. The forming material of the easily adhesive layer is a solution diluted to an appropriate concentration in consideration of the thickness after drying, smoothness of coating, and the like, and is usually adjusted. The thickness of the easily adhesive 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. In addition, although a plurality of easily adhesive layers may be provided, it is preferable that the total thickness of the easily adhesive layer is within the above range even in this case.

The adhesive layer is formed of an adhesive. As the pressure-sensitive adhesive, various pressure-sensitive adhesives can be used, for example, a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a vinylalkyl ether-based pressure-sensitive adhesive, a polyvinylpyrrolidone-based pressure-sensitive adhesive, a polyacrylamide-based pressure-sensitive adhesive, and a cellulose-based pressure-sensitive adhesive. have. According to the type of the pressure-sensitive adhesive, an adhesive base polymer is selected. Among the pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used in that they are excellent in optical transparency, appropriate wettability, cohesiveness and adhesive properties, and excellent weather resistance and heat resistance.

The undercoat layer (primer layer) is formed to improve the adhesion between the polarizer 1 and the protective film 2. The material constituting the primer layer is not particularly limited as long as it is a material that exhibits some degree of strong adhesion to both the polarizer 1 and the protective film 2. For example, a thermoplastic resin having excellent transparency, thermal stability, and stretchability is used. Examples of the thermoplastic resin include acrylic resins, polyolefin resins, polyester resins, polyvinyl alcohol resins, or mixtures thereof.

(2) Coating liquid

The coating liquid contains a resin component or a curable component capable of constituting a transparent resin layer. The transparent resin layer 4 can be formed by applying the said coating liquid to the polarizer 1, and solidifying or hardening.

In addition, the form of the coating liquid (hereinafter, also referred to as a forming material) is not particularly limited as long as it exhibits a liquid state, and any of aqueous, water-dispersible, solvent-free and non-solvent may be used.

The coating solution is advantageous because the lower viscosity tends to penetrate the damaged part when the damaged part is present on the surface of the polarizer 1. The viscosity, as measured at 25°C, is preferably 2000 mPa·s or less, more preferably 1000 mPa·s or less, more preferably 500 mPa·s or less, and particularly preferably 100 mPa·s or less.

It is preferable that the coating solution is applied to the piece protective polarizing film (polarizer side) so that the thickness of the dried coating film (transparent resin layer 4) is 0.2 µm or more. The thickness of the transparent resin layer 4 is more preferably 0.5 μm or more, and even more preferably 0.7 μm or more. On the other hand, when the transparent resin layer 4 is too thick, the optical reliability and water resistance decrease, so the thickness of the transparent resin layer 4 is preferably 3 μm or less, more preferably less than 3 μm, and even more preferably 2 μm or less. Do.

Various methods are used as a method of applying the coating solution. Specifically, for example, extrusion by 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. Methods, such as a coat method, are mentioned.

As a material for forming the transparent resin layer 4, for example, polyester resin, polyether resin, polycarbonate resin, polyurethane resin, silicone resin, polyamide resin, polyimide resin, polyvinyl alcohol (PVA) resin, acrylic resin, epoxy resin, etc. are mentioned. These resin materials may be used alone or in combination of two or more, but among them, at least one selected from the group consisting of polyurethane-based resins, polyvinyl alcohol-based resins, acrylic resins, and epoxy-based resins is preferred. , Polyvinyl alcohol resin and acrylic resin are more preferable.

As the coating solution, a coating solution containing a resin component dissolved or dispersed in water is preferable. A resin component dissolved or dispersed in water refers to a resin dissolved in water and a resin soluble in water at room temperature (25°C) dissolved in an aqueous solvent. If the coating liquid is water-based or water-dispersible, when a damaged part exists on the surface of the polarizer 1, the surface of the polarizer 1 swells, which is advantageous because the coating liquid soaks into the damaged part. That is, if the coating liquid is water-based or water-dispersible, the orientation of the polyvinyl alcohol molecules around the damaged portion constituting the polarizer can be partially relaxed and the boric acid content around the damaged portion can be reduced. Even if the thickness of 4) is small (for example, less than 3 µm, preferably less than 2 µm), 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 phenol resin, polyethylene. Oxide, carboxymethyl cellulose, and the like. These may be used alone, or may be used in combination of a plurality. As the resin component, polyvinyl alcohol-based resin, poly(meth)acrylic acid, and methylolated melamine are preferably used. In particular, from the viewpoint of adhesion to the polyvinyl alcohol-based resin constituting the polarizer, the resin component is preferably a polyvinyl alcohol-based resin. Hereinafter, a case where a polyvinyl alcohol-based resin is used will be described.

The transparent resin layer 4 is preferably formed of a forming material (coating liquid) containing a polyvinyl alcohol-based resin. The polyvinyl alcohol-based resin forming the transparent resin layer may be the same as or different from the polyvinyl alcohol-based resin contained in the polarizer, as long as it is a "polyvinyl alcohol-based resin".

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. Further, examples of the polyvinyl alcohol-based resin include saponified products of a copolymer of vinyl acetate and a copolymerizable monomer. When the copolymerizable monomer is ethylene, an ethylene-vinyl alcohol copolymer is obtained. Further, examples of the copolymerizable monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, and (meth)acrylic acid, and esters thereof; Α-olefins such as ethylene and propylene, (meth)allylsulfonic acid (soda), sodium sulfonic acid (monoalkyl maleate), disulfonic acid sodium alkyl maleate, N-methylol acrylamide, acrylamide alkyl sulfonic acid alkali salt, N- Vinylpyrrolidone, N-vinylpyrrolidone derivatives, and the like. These polyvinyl alcohol-based resins may be used alone or in combination of two or more.

The saponification degree of the polyvinyl alcohol-based resin may be, for example, 95 mol% or more, but from the viewpoint of satisfying moist heat resistance and water resistance, the saponification degree is preferably 99 mol% or more, and further preferably 99.7 mol% or more. The degree of saponification represents the ratio of units that are actually saponified into vinyl alcohol units among units that can be converted into vinyl alcohol units by saponification, and the residue is a vinyl ester unit. The degree of saponification can be obtained according to JIS-K6726-1994.

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

In addition, as the polyvinyl alcohol-based resin, a modified polyvinyl alcohol-based resin having a hydrophilic functional group in the side chain of the polyvinyl alcohol or its copolymer may 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 acid esterification, etc. of a polyvinyl alcohol-based resin may be used.

The ratio of the polyvinyl alcohol-based resin in the transparent resin layer 4 or the coating liquid (solid content) is preferably 80% by weight or more, more preferably 90% by weight or more, and even more preferably 95% by weight or more.

The coating solution is prepared by dissolving the polyvinyl alcohol-based resin in a solvent. Examples of the solvent include water, dimethylsulfoxide, dimethylformamide, dimethylaceto, amide N-methylpyrrolidone, various glycols, polyhydric alcohols such as trimethylolpropane, amines such as ethylenediamine and diethylenetriamine. Can be lifted. These can 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 (e.g., aqueous solution) is not particularly limited, but in consideration of coating properties and standing stability, 0.1 to 15% by weight is preferable, and 0.5 to 10% by weight is more desirable.

In addition, an additive may be added to the coating liquid (eg, aqueous solution). Examples of the additives include plasticizers and surfactants. As a plasticizer, polyhydric alcohols, such as ethylene glycol and glycerin, are mentioned, for example. As a surfactant, a nonionic surfactant is mentioned, for example. Further, coupling agents such as silane coupling agents and titanium coupling agents, various tackifiers, ultraviolet absorbers, antioxidants, heat-resistant stabilizers, and stabilizers such as hydrolysis-resistant stabilizers may be blended.

Next, in the formation of the transparent resin layer 4, a case where a coating liquid containing a curable component capable of constituting the transparent resin layer is used will be described. The curable component can be broadly divided into an active energy ray-curable type such as an electron beam curable type, an ultraviolet curable type, and a visible ray curable type, and a thermal curable type. Further, the ultraviolet curing type and the visible ray curing type can be classified into a radical polymerization curing type and a cationic polymerization curing type. In the present invention, active energy rays having a wavelength range of 10 nm to less than 380 nm are referred to as ultraviolet rays, and active energy rays having a wavelength range of 380 nm to 800 nm are referred to as visible rays. The radical polymerization curable curable component may be used as a thermosetting curable component.

(Radical polymerization curable forming material)

Examples of the curable component include radical polymerizable compounds. The radical polymerizable compound includes a compound having a radically polymerizable functional group of a carbon-carbon double bond such as a (meth)acryloyl group and a vinyl group. Any of a monofunctional radical polymerizable compound or a difunctional or higher polyfunctional radical polymerizable compound can be used as these curable components. In addition, these radically polymerizable compounds may be used singly or in combination of two or more. As these radically polymerizable compounds, for example, a compound having a (meth)acryloyl group is preferable. In addition, in the present invention, (meth)acryloyl means an acryloyl group and/or a methacryloyl group, and "(meth)" has the same meaning as follows.

(Monofunctional radical polymerizable compound)

Examples of the monofunctional radical polymerizable compound include a (meth)acrylamide derivative having a (meth)acrylamide group. The (meth)acrylamide derivative is preferable in that the adhesion to the polarizer is secured, the polymerization rate is high, and the productivity is excellent. Specific examples of the (meth)acrylamide derivative include, for example, N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N-isopropyl ( N-alkyl group-containing (meth)acrylamide derivatives such as meth)acrylamide, N-butyl (meth)acrylamide, and N-hexyl (meth)acrylamide; N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as N-methylol (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, and N-methylol-N-propane (meth)acrylamide; N-aminoalkyl group-containing (meth)acrylamide derivatives such as aminomethyl (meth)acrylamide and aminoethyl (meth)acrylamide; N-alkoxy group-containing (meth)acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide; And N-mercaptoalkyl group-containing (meth)acrylamide derivatives such as mercaptomethyl (meth)acrylamide and mercaptoethyl (meth)acrylamide. In addition, as a heterocycle-containing (meth)acrylamide derivative in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle, for example, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryl Roylpiperidine, N-acryloylpyrrolidine, and the like.

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

Further, 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 -(Meth)acrylic acid (carbon number 1 to 20) alkyl esters such as ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, and n-octadecyl (meth)acrylate. have.

In addition, 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)acrylic Polycyclic (meth)acrylates such as acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentanyl (meth)acrylate;

2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethylcarbitol ( Alkoxy groups, such as meth)acrylate, phenoxyethyl (meth)acrylate, and alkylphenoxy polyethylene glycol (meth)acrylate, or phenoxy group-containing (meth)acrylate, etc. are mentioned.

In addition, as the (meth)acrylic acid derivative, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl ( Meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12 -Hydroxyalkyl (meth)acrylates such as hydroxylauryl (meth)acrylate, [4-(hydroxymethyl)cyclohexyl]methylacrylate, cyclohexanedimethanol mono(meth)acrylate, 2- Hydroxyl group-containing (meth)acrylates such as hydroxy-3-phenoxypropyl (meth)acrylate;

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

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

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

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

(Meth)acrylates having heterocycles such as tetrahydrofurfuryl (meth)acrylate, butyrolactone (meth)acrylate, neopentyl glycol hydroxypivalate (meth)acrylic acid adduct, p-phenylphenol (meth) ) Acrylate, etc. are mentioned.

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

Further, examples of the monofunctional radical polymerizable compound include lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; Vinyl-based monomers having nitrogen-containing heterocycles such as vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine.

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

(Polyfunctional radical polymerizable compound)

In addition, as a bifunctional or higher polyfunctional radical polymerizable compound, for example, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1, 9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide Adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecane di Methanol di(meth)acre, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, (Meth)acrylic acid and polyhydric acid such as pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, EO-modified diglycerin tetra(meth)acrylate Esterified products with alcohol, and 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. Specific examples include Aronix M-220, M-306 (manufactured by Toa Kosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), and light acrylate DGE-4A. (Kyoeisha Chemical Co., Ltd. make), light acrylate DCP-A (Kyoeisha Chemical Co., Ltd. make), SR-531 (Sartomer Corporation make), CD-536 (Sartomer Corporation make), etc. are mentioned. . Further, if necessary, various types of epoxy (meth)acrylate, urethane (meth)acrylate, polyester (meth)acrylate, various (meth)acrylate-based monomers, and the like may be mentioned.

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

(Mode of radical polymerization curable forming material)

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

(Photopolymerization initiator)

In the case of using a radical polymerizable compound, the photoinitiator is appropriately selected by active energy rays. In the case of curing by ultraviolet or visible light, a photopolymerization initiator of ultraviolet 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-hydroxyl) Aromatic ketone compounds such as oxy-2-propyl) ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and α-hydroxycyclohexylphenyl ketone; Methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane Acetophenone compounds such as -1; Benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; Aromatic ketal compounds such as benzyl dimethyl ketal; Aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; Photoactive oxime compounds such as 1-phenone-1,2-propanedione-2-(o-ethoxycarbonyl) oxime; Thioxanthone, 2-chloro thioxanthone, 2-methyl thioxanthone, 2,4-dimethyl thioxanthone, isopropyl thioxanthone, 2,4-dichloro thioxanthone, 2,4-diethyl thioxanthone Thioxanthone compounds such as santon, 2,4-diisopropyl thioxanthone, and dodecyl thioxanthone; Camphorquinone; Halogenated ketones; Acylphosphine oxide; Acyl phosphonate, etc. are mentioned.

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

In addition, in the case of using in a visible light curing type containing a radical polymerizable compound as a curable component, it is particularly preferable to use a photopolymerization initiator that is highly 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 the photopolymerization initiator, a compound represented by the following formula (1);

[Formula 1]

(In the formula, R ¹ and R ² represent -H, -CH ₂ CH ₃ , -iPr or Cl, and R ¹ and R ² may be the same or different.) or as formula (1) It is preferable to use together the compound to be displayed and a photoinitiator of high sensitivity to light of 380 nm or more described later. When the compound represented by the formula (1) is used, adhesion is excellent compared to 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 formula (1), diethylthioxanthone in which R ¹ and R ² are -CH ₂ CH ₃ is particularly preferable. The composition ratio of the compound represented by the formula (1) in the forming material (coating liquid) is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, and 0.9 It is more preferably 3 parts by weight.

Moreover, it is preferable to add a polymerization initiation aid as needed. As a polymerization initiator, triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoic acid isoa Wheat, and the like, and ethyl 4-dimethylaminobenzoate is particularly preferred. When a polymerization initiation aid is used, the addition amount is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component.

In addition, a known photopolymerization initiator can be used in combination as necessary. Since the protective film having a UV absorbing function does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator with high sensitivity 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)-buta Non-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 Ro-3-(1H-pyrrol-1-yl)-phenyl) titanium and the like.

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

[Formula 2]

(In the formula, R ³ , R ⁴ and R ⁵ represent -H, -CH ₃ , -CH ₂ CH ₃ , -iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different) It is preferable to use. As the compound represented by the formula (2), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: IRGACURE 907, manufactured by BASF), which is also a commercial product, is preferably used. Can be used. In addition, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name: IRGACURE 369, manufactured by BASF), 2-(dimethylamino)-2-[(4 -Methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: IRGACURE 379, manufactured by BASF) is preferred because of its high sensitivity.

(Thermal polymerization initiator)

As a thermal polymerization initiator, it is preferable that polymerization does not start by thermal cleavage. For example, the thermal polymerization initiator preferably has a 10-hour half-life temperature of 65°C or higher, and further 75 to 90°C. In addition, the half-life is an index indicating the decomposition rate of the polymerization initiator, and refers to the time until the residual amount of the polymerization initiator becomes half. The decomposition temperature for obtaining a half-life at an arbitrary time and the half-life at an arbitrary temperature are described in the maker's catalog, for example, "Organic Peroxide Catalog 9th Edition (May 2003)" of Nippon Yushi Co., Ltd. It is described.

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-butylperoxycarbonate (10 hour half-life temperature: 51°C), t-butylperoxyneodecanoate (10 hour half-life temperature: 48°C), t-hexylperoxypivalate, t-butylperoxypival Rate, 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 (10 hour half-life temperature: 73°C), t-butylperoxyisobutylate (10 hour half-life temperature: 81°C), 1, Organic peroxides, such as 1-di(t-hexylperoxy)cyclohexane, are mentioned.

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

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

(Cationic 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 preferred epoxy compound, a compound (aromatic epoxy compound) having at least two epoxy groups in the molecule and at least one aromatic ring or at least two epoxy groups in the molecule, of which at least one is adjacent 2 constituting an alicyclic ring A compound (alicyclic epoxy compound) formed between four carbon atoms and the like can be exemplified.

(Photo cationic polymerization initiator)

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

1-2. Solidification or hardening process

The production method of the present invention includes a step of solidifying or curing the obtained coating film. The transparent resin layer 4 can be formed by solidifying or curing the coating film.

When the coating solution is a coating solution containing a resin component, in the formation of the transparent resin layer 4, after the coating solution is applied, the resin component is solidified according to the type. The coating liquid containing the resin component is a solution or dispersion obtained by dissolving the resin component in a solvent, and is used, for example, as an aqueous solution, an aqueous dispersion, or a solvent-based solution. The solidification refers to forming the transparent resin layer 4 by removing the solvent from the coating solution. For example, when the resin component is a polyvinyl alcohol-based resin, the coating solution may be used as an aqueous solution, and solidification may be performed by heating (drying) or the like. Further, even when the resin component is water-soluble acrylic, solidification can be similarly performed.

The drying temperature is not particularly limited, and is usually about 60 to 200°C, but in the present invention, it is preferably 120°C or less, and more preferably 100°C or less from the viewpoint of curl suppression. The drying time is preferably within 180 seconds, more preferably within 120 seconds, and even more preferably within 60 seconds.

On the other hand, in the formation of the transparent resin layer 4, after applying a coating solution containing a curable component capable of constituting the transparent resin layer, the curable component forms a transparent resin layer according to the type of the curable component. Curing as much as possible. The coating liquid containing a curable component capable of constituting the resin can be used in a solvent-free system as long as the curable component represents a coating liquid. In addition, as the coating liquid, a solution obtained by dissolving the curable component in a solvent can be used. Further, even when the curable component represents a coating liquid, it can be used as a solution. As the solvent, it can be appropriately selected according to the curable component to be used. For example, when an acrylic monomer forming an acrylic resin is used as the curable component, or when an epoxy monomer forming an epoxy resin is used, the coating solution containing the curable component is irradiated with active energy rays (ultraviolet irradiation). Curing can be performed.

The formation of the transparent resin layer 4 by the curable forming material (coating liquid) is performed by coating a curable forming material on the surface of a polarizer and then curing.

The polarizer 1 may be subjected to a surface modification treatment before applying the curable forming material. Specific treatments include corona treatment, plasma treatment, and saponification treatment.

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 ray-curable type. In the aspect of the above-described curable forming material, an active energy ray-curable forming material is preferable to a heat-curable forming material from the viewpoint of productivity, and further, as the active energy ray-curable forming material, a visible ray-curable forming material is preferable from the viewpoint of productivity.

(Active energy ray curing type)

In the active energy ray-curable forming material, the active energy ray-curable forming material is applied to the polarizer, and then the active energy ray-curable forming material is cured by irradiating the active energy ray (electron beam, ultraviolet ray, visible light, etc.) to the transparent resin layer (4). To form. The irradiation direction of the active energy ray (electron ray, ultraviolet ray, visible ray, etc.) can be irradiated from any suitable direction. Preferably, it irradiates from the transparent resin layer 4 side.

(Electron beam hardening type)

In the electron beam curing type, any suitable conditions may be employed as long as the irradiation condition of the electron beam is a condition capable of curing the active energy ray curing type forming material. For example, in electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5kV, there is a fear that the electron beam does not reach the deepest part of the transparent resin layer (4), which may lead to insufficient curing. If the acceleration voltage exceeds 300kV, the penetration force passing through the sample is too strong, so the protective film (2) There is a risk of damaging the polarizer (1). The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the transparent resin layer 4 becomes insufficiently cured, and when it exceeds 100 kGy, the protective film or polarizer is damaged, resulting in a decrease in mechanical strength or yellowing, and a predetermined optical property cannot be obtained. .

Electron beam irradiation is usually carried out in an inert gas, but if necessary, it may be carried out in the atmosphere or under conditions in which oxygen is slightly introduced.

(Ultraviolet ray curing type, visible ray curing type)

In the production method of the present invention, it is preferable to use, as the active energy ray, one containing visible light having a wavelength range of 380 nm to 450 nm, and in particular, an active energy ray having the largest irradiation amount of visible light having a wavelength range of 380 nm to 450 nm. As the active energy ray according to the present invention, a gallium-encapsulated metal halide lamp and an LED light source emitting light in a 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 ultraviolet and visible light such as sunlight A light source including a may be used, and ultraviolet rays having a wavelength shorter than 380 nm may be blocked using a band pass filter.

(Heat curing type)

On the other hand, in the thermosetting forming material, polymerization is initiated by a thermal polymerization initiator by heating to form a cured product layer. The heating temperature is set depending on the thermal polymerization initiator, but is about 60 to 200°C, preferably 80 to 150°C.

2. Manufacturing method of polarizing film with adhesive layer

The manufacturing method of the polarizing film with a pressure-sensitive adhesive layer of the present invention is characterized by including a step of forming a pressure-sensitive adhesive layer on the transparent resin layer 4 of the piece protective polarizing film with a transparent resin layer obtained by the above manufacturing method.

(1) adhesive layer

An appropriate pressure-sensitive adhesive can be used to form the pressure-sensitive adhesive layer, and there is no particular limitation on the kind. Examples of the adhesive include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, urethane-based adhesives, vinylalkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, and cellulose-based adhesives.

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

As a method of forming the pressure-sensitive adhesive layer, for example, the pressure-sensitive adhesive is applied to a separator in which the pressure-sensitive adhesive has been peeled off, and the polymerization solvent is dried and removed to form the pressure-sensitive adhesive layer, and then transferred onto the transparent resin layer 4 or a transparent resin layer. It is produced by a method of forming an adhesive layer on the transparent resin layer 4 by applying the pressure-sensitive adhesive to (4) and drying and removing a polymerization solvent or the like. Further, in the application of the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be appropriately added.

As the separator subjected to the release treatment, a silicone release liner is preferably used. In the process of forming the pressure-sensitive adhesive layer by applying and drying the pressure-sensitive adhesive on such a liner, a suitable and appropriate method may be adopted according to the purpose as a method of drying the pressure-sensitive adhesive. Preferably, a method of heating and drying the coating film can be used. The heating drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and still more preferably 70°C to 170°C. By setting the heating temperature in the above range, a pressure-sensitive adhesive having excellent adhesion properties can be obtained.

The drying time is suitable and an appropriate time can be adopted. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and even more preferably 10 seconds to 5 minutes.

Various methods can be used as a method for forming the pressure-sensitive adhesive layer. Specifically, for example, extrusion coating by 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. Methods, such as a law, are mentioned.

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

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a peel-treated sheet (separator) until it is provided for actual use.

As a constituent material of the separator, for example, a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, a porous material such as paper, fabric, and non-woven fabric, a net, a foam sheet, a metal foil, and an appropriate thin leaf such as a laminate thereof Although a (薄葉) body and the like are mentioned, a plastic film is preferably used from the viewpoint of excellent surface smoothness.

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

The thickness of the separator is usually about 5 to 200 µm, preferably about 5 to 100 µm. The separator may be treated to prevent release and contamination by silicon-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agents, silica powder, etc., or antistatic treatment such as coating type, kneading type, evaporation type, etc. . In particular, by appropriately performing a peeling treatment such as a silicone treatment, a long chain alkyl treatment, or a fluorine treatment on the surface of the separator, the peelability in the pressure-sensitive adhesive layer can be further improved.

(2) surface protection film

A surface protective film can be provided on the polarizing film of the present invention (including a single protective polarizing film and a polarizing film with an adhesive layer). The surface protection film usually has a base film and an adhesive layer, and protects a polarizing film through the said adhesive layer.

As the base film of the surface protection film, a film material having isotropic or near isotropic is selected from the viewpoint of inspection properties and manageability. Examples of the film material include polyester resins such as polyethylene terephthalate films, cellulose resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, And transparent polymers such as acrylic resins. Among these, polyester resins are preferred. The base film may be used as a laminate of one or two or more film materials, or a stretched product of the film may be used. The thickness of the base film is generally 500 µm or less, preferably 10 to 200 µm.

As the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer of the surface protection film, appropriately select a pressure-sensitive adhesive made of a polymer such as (meth)acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer as the base polymer. Can be used. From the viewpoint of transparency, weather resistance, heat resistance, and the like, an acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer is preferable. The thickness of the pressure-sensitive adhesive layer (dry film thickness) is determined according to the required adhesive strength. It is usually about 1 to 100 µm, preferably 5 to 50 µm.

In addition, in the surface protective film, a peeling treatment layer can be provided on the opposite surface of the surface on which the pressure-sensitive adhesive layer is provided in the base film using a low-adhesive material such as silicone treatment, long chain alkyl treatment, or fluorine treatment.

3. Manufacturing method of optical laminate

The manufacturing method of the optical laminate of the present invention is characterized by including a step of bonding to an optical member via the pressure-sensitive adhesive layer without winding up the polarizing film with an adhesive layer obtained by the manufacturing method.

Since curl is suppressed in the unprotected polarizing film with a transparent resin layer obtained by the production method of the present invention and the polarizing film with an adhesive layer using the unprotected polarizing film with the transparent resin layer, the film is not wound on a roll or the like, Can be used in the process. That is, an optical laminate can be manufactured by bonding to an optical member through an adhesive layer. When a single-protective polarizing film (attached with a transparent resin layer) is produced by a conventional manufacturing method, curling may occur at the end of the film, and if curling occurs, the film is folded or wrinkled at the end of the film when conveyed to the next process. Since rupture occurs, it was difficult to use as it is in the next step.

The optical member is not particularly limited, but is used to form a liquid crystal display such as a reflective plate, a transflective plate, a retardation plate (including a wavelength plate such as 1/2 or 1/4), and a visual compensation film. One or two or more layers may be used. As the optical laminate, in particular, a reflective polarizing film or a semi-transmissive polarizing film obtained by laminating a reflecting plate or a semi-transmissive reflecting plate further to the polarizing film with an adhesive layer obtained by the production method of the present invention, obtained by the production method of the present invention A wide viewing angle polarizing film comprising an elliptically polarizing film or a circular polarizing film obtained by laminating a polarizing film with a pressure-sensitive adhesive layer and a retardation plate further, a polarizing film with a pressure-sensitive adhesive layer obtained by the manufacturing method of the present invention, and a visual compensation film Alternatively, a polarizing film obtained by laminating a brightness improving film further on the polarizing film with an adhesive layer obtained by the production method of the present invention is preferable.

The optical laminate in which the optical member is laminated on the polarizing film with a pressure-sensitive adhesive layer of the present invention can be formed by sequentially laminating separately in the manufacturing process of a liquid crystal display, etc., but the quality There is an advantage of improving the manufacturing process of a liquid crystal display device due to excellent stability and assembly work. In the case of laminating two or more layers of optical members, appropriate bonding means such as an adhesive layer can be used. When bonding the polarizing film with the pressure-sensitive adhesive layer, these optical axes can be set to an appropriate arrangement angle depending on the desired retardation characteristics and the like.

The single protective polarizing film with a transparent resin layer, a polarizing film with an adhesive layer, or an optical laminate obtained by the production method of the present invention can be preferably used for formation of various devices such as a liquid crystal display device. The liquid crystal display device may be formed according to the conventional method. That is, a liquid crystal display device is generally formed by properly assembling a liquid crystal cell, a single protective polarizing film or an optical film with a transparent resin layer, and constituent parts such as a lighting system as necessary to embed a driving circuit, but in the present invention There is no restriction|limiting in particular except for using the piece protective polarizing film with a transparent resin layer obtained by the manufacturing method of this invention, the polarizing film with an adhesive layer, or an optical laminated body, and it may follow existing. Regarding the liquid crystal cell, for example, any kind of IPS type, VA type or the like can be used, but it is particularly preferable for the IPS type.

On one side or both sides of a liquid crystal cell, a backlight or a reflector is used in a liquid crystal display device or a lighting system in which a transparent resin layer-attached polarizing film obtained by the production method of the present invention, a polarizing film with an adhesive layer, or an optical laminate is disposed. It is possible to form an appropriate liquid crystal display device such as one. In that case, the single protective polarizing film with a transparent resin layer obtained by the manufacturing method of this invention, the polarizing film with an adhesive layer, or the optical laminated body can be provided on one side or both sides of a liquid crystal cell. When a single protective polarizing film with a transparent resin layer obtained by the production method of the present invention, a polarizing film with an adhesive layer, or an optical laminate is provided on both sides, these may be the same or different. In addition, when forming a liquid crystal display, for example, a diffusion plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, etc. It can be placed above.

[Example]

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, in each example, both parts and% are based on weight. Unless otherwise specified below, the conditions for standing at room temperature are all 23°C and 65% R.H.

Manufacturing Example 1 (Production of a polarizer)

Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having an absorption rate of 0.75% and a glass transition temperature (Tg) of 75°C was subjected to corona treatment on one side of the substrate, and polyvinyl on the corona treated side Alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (trade name: high fimer Z200, polymerization degree: 1200, acetoacetyl modification degree: 4.6%, saponification degree: 99.0 mol% or more, Nippon Kosei Chemical Co., Ltd. ) Preparation) in a ratio of 9:1 was applied and dried at 25° C., and a PVA-based resin layer having a thickness of 11 μm was formed to prepare a laminate.

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

Next, the laminate was immersed for 30 seconds in an insolubilization bath having a liquid temperature of 30°C (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, the polarizing plate was immersed in a dyeing bath having a liquid temperature of 30° C. while adjusting the iodine concentration and immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 parts by weight of iodine was blended with respect to 100 parts by weight of water, and 1.0 parts by weight of potassium iodide was blended and immersed in an aqueous iodine solution for 60 seconds (dyeing treatment).

Then, it was immersed for 30 seconds in a crosslinking bath having a liquid temperature of 30°C (a boric acid aqueous solution obtained by mixing 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 an aqueous solution of boric acid at a liquid temperature of 70°C (an aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide) with a liquid temperature of 70°C. Uniaxial stretching was performed so that the total draw ratio became 5.5 times in (longitudinal direction) (underwater stretching treatment).

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

From the above, an optical film laminate including a polarizer having a thickness of 5 μm was obtained.

Production Example 2 (Preparation of a single protective polarizing film)

Corona treatment was applied to the easily-adhesion-treated surface of a (meth)acrylic resin film having a lactone ring structure having a thickness of 40 µm and used as a 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 photo initiator (trade name: IRGACURE 819, manufactured by BASF). This was made into the adhesive for protective films.

After bonding the protective film while applying the UV-curable adhesive to the surface of the polarizer of the optical film laminate obtained in Preparation Example 1 so that the thickness of the cured adhesive layer becomes 1 μm, UV irradiation as an active energy ray was applied to the adhesive. Cured. UV irradiation is a gallium-enclosed metal halide lamp (irradiation device: Light HAMMER 10 manufactured by Fusion UV Systems, Inc., valve: V valve, peak illuminance: 1600 mW/cm ² , accumulated irradiation amount: 1000/mJ/cm ² (wavelength 380 to 440nm)) was used, and the irradiance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Next, the amorphous PET substrate was peeled off, and a single protective polarizing film (total thickness of 46 µm) using a thin polarizer was prepared.

The optical properties of the obtained piece protective polarizing film were 42.8% of single transmittance and 99.99% of polarization degree.

<Single transmittance (T) and polarization degree (P)>

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

In addition, the degree of polarization (P) is the transmittance (parallel transmittance: Tp) when two identical polarizing films are stacked so that their transmission axes are parallel to each other, and the transmittance (orthogonal transmittance) when overlapping the transmission axes of both sheets is orthogonal. :Tc) can be obtained by applying to the following equation.

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

Each transmittance is expressed as a Y value obtained by correcting the visibility according to the second degree field of view (C light source) of JIS Z8701 with 100% of the perfect polarized light obtained through a Glan Taylor prism polarizer.

Production Example 3 (Preparation of a coating liquid forming a transparent resin layer)

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 solution) having a solid content concentration of 4% by weight and a viscosity of 60 mPa·s (25°C).

<Viscosity measurement>

The viscosity of the coating solution was measured under the following conditions using a VISCOMETER R85 viscometer RE85L (manufactured by Toki Industries, Ltd.).

Measurement temperature: 25℃

Number of revolutions: 0.5 to 100 rpm

Cone rotor: 1°34'×R24

Example 1 (Preparation of a single protective polarizing film with a transparent resin layer)

The coating solution (former for transparent resin layer) obtained in Preparation Example 3 was applied to the surface of the polarizer (the polarizer surface on which the protective film was not provided) of the single protective polarizing film obtained in Preparation Example 2 by using a gravure roll to have a thickness of 25 μm. It was applied so as to be. Application was performed on the entire surface in the width direction of the piece protective polarizing film. After coating, hot air drying was performed at 95° C. for 30 seconds using a floating oven to form a 1 μm-thick transparent resin layer, and a single protective polarizing film with a transparent resin layer was prepared.

Example 2, Comparative Example 1

In Example 1, a single protective polarizing film with a transparent resin layer was produced in the same manner as in Example 1 except that the uncoated portion described in Table 1 was formed from both ends in the width direction of the single protective polarizing film toward the inside. .

The following evaluation was performed using the piece protective polarizing film with a transparent resin layer obtained by an Example and a comparative example. The evaluation results are shown in Table 1.

<Curl Occurrence>

The obtained piece protective polarizing film with a transparent resin layer was evaluated for the curl amount of the polarizing plate film immediately after winding under conditions of 23°C and 55% R.H. with the transparent resin layer facing upward. For the curl measurement, a sample was cut into a rhombus shape of 45 degrees with respect to the absorption axis and a piece of 150 mm so that the coating end portion was included, and then the sample was set so that the transparent resin layer side was on a horizontal table. The curl of the coating end portion of the set sample was measured with a ruler, and evaluated according to the following evaluation criteria.

A:10mm or less

B: More than 10mm and less than 30mm

C: more than 30mm

[Table 1]

Curl generation was suppressed in any of the piece protective polarizing films with a transparent resin layer of Examples. On the other hand, in the single protective polarizing film with a transparent resin layer of Comparative Example 1, curls were generated so that the protective film side became convex and the transparent resin layer side became concave.

1: polarizer
2: protective film
3: unprotected polarizing film
4: transparent resin layer
5: uncoated part
10: single protective polarizing film with transparent resin layer
A: the width direction of the polarizing film

Claims (9)

A method for producing a single protective polarizing film having a protective film on only one side of the polarizer and a transparent resin layer having a transparent resin layer provided on the other side of the polarizer of the single protective polarizing film,
The polarizer includes a polyvinyl alcohol-based resin, and has a thickness of 8 μm or less,
The transparent resin layer is formed by a process of applying a coating liquid containing a polyvinyl alcohol-based resin to the polarizer and a process of solidifying the obtained coating film,
The transparent resin layer contains 80% by weight or more of a polyvinyl alcohol-based resin,
In the application process of the coating solution, the coating solution has an uncoated portion not coated with the coating solution in an area of less than 20 mm from both ends in the width direction of the polarizer, or the coating solution over the entire width direction of the polarizer A method for producing a single protective polarizing film with a transparent resin layer, characterized in that applying. The method of claim 1,
The method for producing a single protective polarizing film with a transparent resin layer, wherein the coating solution is applied by applying the coating solution over the entire width direction of the polarizer. The method of claim 1,
The method for producing a single protective polarizing film with a transparent resin layer, characterized in that the width of the polarizer is 1,100 to 2,000 mm. The method of claim 1,
A method for producing a single protective polarizing film with a transparent resin layer, wherein the solidification is performed by drying. The method of claim 4,
The method for producing a single protective polarizing film with a transparent resin layer, wherein the drying temperature is 120°C or less. The method of claim 4,
The method for producing a single protective polarizing film with a transparent resin layer, characterized in that the drying time is within 180 seconds. delete A polarizing film with a pressure-sensitive adhesive layer comprising a step of forming a pressure-sensitive adhesive layer on the transparent resin layer of the piece protective polarizing film with a transparent resin layer obtained by the production method according to any one of claims 1 to 6 Manufacturing method. A method for producing an optical laminate, comprising a step of bonding the polarizing film with an adhesive layer obtained by the production method of claim 8 to an optical member through the pressure-sensitive adhesive layer.

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