TWI597531B - A polarizing film, a polarizing film with an adhesive layer, and an image display device - Google Patents

Description

Polarizing film, polarizing film with adhesive layer and image display device

The present invention relates to a polarizing film. Further, the present invention relates to a polarizing film using an adhesive layer of the aforementioned polarizing film. The polarizing film or the polarizing film with an adhesive layer can form an image display device such as a liquid crystal display (LCD) or an organic EL display device either alone or as an optical film formed by laminating the film.

Background technique

In the liquid crystal display device, it is necessary to arrange a polarizing film on both sides of the glass substrate on which the surface of the liquid crystal panel is formed, based on the image forming method. In general, a polarizing film is obtained by bonding a protective film to a single surface or both surfaces of a polarizing material with a polyvinyl alcohol-based adhesive or the like, and the polarizing member is made of a polyvinyl alcohol-based film and iodine. Made up of color materials.

In addition, in a severe environment where the polarizing film is tested by hot stamping (for example, at 95 ° C for 250 hours), the polarizing film changes due to the contraction stress of the polarizing member, and there is a problem that cracks easily occur in the absorption axis direction of the polarizing member. . That is, the polarizing film is insufficient in crack resistance against thermal shock of the aforementioned severe environment. In particular, from the viewpoint of thinning, the one-side protective polarizing film provided with only the protective film on one side of the polarizing member is provided with a difference in shrinkage stress of the polarizing member on the side of the protective film and a contraction stress of the polarizing member on the opposite side of the protective film. When a squeaking stress occurs inside the polarizer, there is a problem that various cracks such as a through crack such as a through crack appearing in the absorption axis direction of the polarizer easily occur in the absorption axis direction of the polarizer.

In order to suppress the occurrence of the above-mentioned cracks, for example, a polarizing film with an adhesive layer has been proposed, which is provided with a protective layer having a tensile modulus of 100 MPa or more on the one-side protective polarizing film, and further adhesive is provided on the protective layer. Agent layer (Patent Document 1). Further, a polarizing film with an adhesive layer which has a protective layer composed of a cured product of a hardened resin composition on one surface of a polarizing member having a thickness of 25 μm or less and a single side on the other side of the polarizing member is also proposed. The protective film is provided thereon, and an adhesive layer is provided outside the protective layer (Patent Document 2). The polarizing film with an adhesive layer described in the above Patent Documents 1 and 2 is effective from the viewpoint of suppressing occurrence of cracks. In addition, from the viewpoint of suppressing the occurrence of cracks and reducing the thickness and weight, it has been proposed to provide a coating composed of a water-soluble film forming composition (polyvinyl alcohol resin composition) on at least one surface of the polarizing material. Layer (Patent Document 3).

Advanced technical literature Patent literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-009027

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2013-160775

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2005-043858

Summary of invention

Further, according to Patent Documents 1 to 3, the shrinkage of the polarizer in the absorption axis direction can be controlled to some extent by the protective layer, and the occurrence of the above-mentioned crack can be suppressed. However, even with the aforementioned protective layer, it is difficult to sufficiently suppress the dimensional change of the polarizer due to the shrinkage stress.

Moreover, the polarizer is also becoming thinner. When the polarizing member used for the polarizing film is thinned, the change in the shrinkage stress of the polarizing member is reduced. However, since the polarizing member itself is thinned, the polarizing member is broken even if a force weaker than the conventional technique is applied, so that even with the thin polarizing member, the crack resistance is insufficient.

Further, since the polarizing member has an extending step such as a polyvinyl alcohol-based film, even in the case of the thin polarizing member, the polarizing member obtained in the extending step is manufactured with residual stress inside. Further, in general, the polarizing film has various protective films or the like adhered to one surface or both surfaces of the polarizing member, but the residual stress of the various protective films and the residual stress of the polarizing member in the thermal filming test of the polarizing film are In the form of a combination, the polarizing film shows the dynamics of shrinkage as a whole. Therefore, even in the case of a thin polarizing member, particularly in the vicinity of the Tg of the polyvinyl alcohol resin for forming the polarizing member and above (for example, 85 ° C or higher), the size of the polarizing member due to the shrinkage stress cannot be sufficiently suppressed. Variety.

An object of the present invention is to provide a polarizing film which has a transparent layer on at least one surface of a polarizing member, can suppress crack occurrence in a high temperature environment of 85 ° C or higher, and can suppress dimensional change of the polarizer. Further, it is an object of the invention to provide a polarizing film using an adhesive layer of the above polarizing film. The invention further relates to an image display device The polarizing film of the foregoing polarizing film or adhesive layer is provided.

As a result of intensive investigation, the inventors of the present invention have found that the above problems can be solved by the following polarizing film or the like, and the present invention is completed.

That is, the present invention relates to a polarizing film which has a transparent layer on at least one side of a polarizing member, wherein the polarizing member contains a polyvinyl alcohol resin and has a thickness of 15 μm or less; and the transparent portion of the polarizing member The layer side has a compatibility layer with the transparent layer; and the thickness A of the polarizer and the thickness B of the compatibility layer satisfy the general formula: (100 × B / A) ≧ 1.

In the polarizing film, the phase of the phase of the polarizing member is preferably a lower concentration of boric acid than the portion of the polarizing member.

Further, the present invention relates to a polarizing film having a transparent layer on at least one surface of a polarizing member, wherein the polarizing member contains a polyvinyl alcohol-based resin and has a thickness of 15 μm or less; and the transparent layer in the polarizing member The side has a low concentration layer of boric acid, which is relatively low in boric acid concentration compared with the other portions of the polarizer; and the thickness A of the polarizer and the thickness C of the boric acid low concentration layer satisfy the general formula: (100×C/A) ≧1.

In the polarizing film, the thickness of the transparent layer is preferably 0.2 μm or more. Further, the thickness of the transparent layer is preferably 6 μm or less.

In the polarizing film, the alignment index of the transparent layer is preferably 0.05 or less.

In the polarizing film, the transparent layer is preferably a formed product of a material containing a polyvinyl alcohol resin. The polyvinyl alcohol-based resin preferably has a degree of saponification of 99 mol% or more and an average degree of polymerization of 2,000 or more.

In the polarizing film, the optical characteristics of the polarizing element T and the degree of polarization P of the polarizing member are preferably in the range of the following formula: P>-(10 ^0.929T-42.4 -1)×100 (but T<42.3); or P≧99.9 (but T≧42.3).

The aforementioned polarizing film may have a protective film.

Further, the present invention relates to a polarizing film with an adhesive layer characterized by comprising the above-mentioned polarizing film and an adhesive layer.

Furthermore, the present invention relates to an image display device comprising the polarizing film or the polarizing film of the adhesive layer.

According to the polarizing film of the present invention, by providing the transparent layer in the polarizing member, crack generation can be suppressed in a high temperature environment of 85 ° C or higher. Further, the polarizing film of the present invention has a compatibility layer with the transparent layer on the side of the transparent layer of the polarizing member. The phase of the foregoing phase is formed in the vicinity of the surface of the polarizer by a part of the material forming the transparent layer penetrating into the polarizer and oozing out of the component near the surface of the polarizer. A transparent layer may be formed on the surface of the polarizer by using a material permeable to the polarizing member to form the phase-soluble layer.

For example, generally, the polarizing member is produced by performing an extending step on a polyvinyl alcohol-based resin (film), and thus the obtained polarizing member The resin molecules will assume a state of regularity and orientation. On the other hand, the transparent layer formed on the surface of the polarizer is formed, for example, by coating. Therefore, the transparent layer does not perform the stretching step, and the molecules forming the transparent layer are not regularly oriented. The phase-soluble layer of the present invention is formed by infiltrating a forming component of a transparent layer into a polarizing member as described above. When the transparent layer is formed, the transparent layer component penetrating into the polarizing member has a function of partially alleviating the molecular alignment in the polarizing member. It is presumed that such a function is related to the relaxation of the residual stress of the polarizer, and the dimensional change of the polarizer is suppressed. Moreover, the present invention is not limited by this presumptive mechanism.

Further, the polarizing film of the present invention uses a thin polarizing member having a thickness of 15 μm or less. Although the change in the shrinkage stress of the polarizer in the thin polarizer is small, the crack resistance is not sufficient because the polarizer itself is thinned. According to the polarizing film of the present invention, crack resistance can be improved by having a transparent layer even if a thin polarizing member is used.

1‧‧‧ polarizer

2‧‧‧Transparent layer

3‧‧‧Resin substrate

4‧‧‧Protective film

10‧‧‧Polarized film

11‧‧‧ polarizing film

A‧‧‧ polarizer thickness

B‧‧‧Composition layer thickness

X‧‧‧compatible layer

Fig. 1 is a view showing an example of a schematic cross-sectional view of a polarizing film of the present invention.

Fig. 2 is a view showing an example of a schematic cross-sectional view of a polarizing film of the present invention.

Figure 3 is a graph showing the correlation of the dissolved layers.

Form for implementing the invention

Hereinafter, the polarizing films 10 and 11 of the present invention will be described with reference to Figs. 1 and 2 . The polarizing films 10 and 11 have a polarizer 1 and a transparent layer 2. Further, as shown in FIGS. 1 and 2, the polarizing films 10 and 11 of the present invention have a compatibility layer X with the transparent layer 2 on the side of the transparent layer 2 of the polarizer 1. Figure 1(A) shows only the polarizer 1, the compatibility layer X, and the transparent layer 2. However, as shown in Fig. 1(B), the resin substrate 3 may be provided on the side of the polarizer 1 in Fig. 1(A). The resin substrate 3 can be, for example, a resin substrate used in the production of the thin polarizer 1 .

Further, in the polarizing film 11 of Fig. 2, the protective film 4 is provided on the polarizing film 10 of Fig. 1(A). The protective film 4 can be provided on one or both sides of the polarizing film of the polarizing film 10 of Fig. 1(A). In FIG. 2(A), the protective film 4 is provided only on the side of the polarizer 1, but the protective film 4 may be provided only on the side of the transparent layer 2. 2(B) is a protective film 4 provided on both sides of the polarizing film 10 of FIG. 1(A). Further, the protective film 4 may be used in two or more layers. Fig. 2(C) shows a case where two protective films 4 are laminated on one side of the polarizing member 1. Further, although not shown in FIG. 2, the polarizer 1, the transparent layer 2, and the protective film 4 may be laminated via an interposer such as an adhesive layer, an adhesive layer, or an undercoat layer (primer layer). Further, although not shown, an easy adhesion layer or an activation treatment may be provided on the protective film 4, and the easy-adhesion layer and the adhesive layer may be laminated.

Further, although not shown, the polarizing films 10 and 11 of the present invention may be provided with an adhesive layer. Further, a spacer may be provided on the adhesive layer. Further, the polarizing film 10, 11 of the present invention (especially when the protective film 4 is provided) may be provided with a surface protective film.

In the polarizing film 10, 11 of the present invention, the phase forming layer X is a layer formed by a transparent layer 2 penetrating from the surface of the polarizing member 1 to the inside, and the residual stress of the polarizing member 1 can be alleviated by the phase-soluble layer X. . As a result, the dimensional change of the polarizer can be suppressed. From this point of view, in the present invention, the thickness A of the polarizer 1 and the thickness B of the compatibility layer are adjusted to satisfy the general formula: (100 × B / A) ≧ 1. The thickness B of the phase-soluble layer X is thicker than the polarizer 1 The relationship of degree A is adjusted. The value of (100 × B / A) is preferably 2 or more from the viewpoint of relaxing the residual stress of the polarizer, and is preferably 2.5 or more, preferably 3 or more, more preferably 4 or more, and more preferably 5 or more. . On the other hand, when the value of (100 × B / A) is too large, the ratio of the compatibility layer X in the thickness A of the polarizer 1 is too large to impair the optical characteristics. From this point of view, the value of (100 × B / A) is preferably 10 or less, more preferably 7 or less.

The thickness B of the aforementioned phase-soluble layer X can be measured by the method described in the examples.

<polarizer>

The polarizing member is not particularly limited, and various types can be used. The polarizing member may, for example, be a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene/vinyl acetate copolymer-based partially saponified film, or a dichroic dye. A coloring substance and a uniaxially stretched product thereof; and a polyene-based oriented film such as a dehydrated material of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Among them, a polarizing member comprising a polyvinyl alcohol-based film and a dichroic material such as iodine is preferred.

The polarizing member obtained by dyeing a polyvinyl alcohol-based film by iodine and then uniaxially stretching can be produced, for example, by dipping a polyvinyl alcohol film into an aqueous solution of iodine to be dyed, and then extending to the original length of 3 to 7. Times. The boric acid, zinc sulfate, zinc chloride or the like may be contained as needed, or may be immersed in an aqueous solution of potassium iodide or the like. The polyvinyl alcohol-based film may be immersed in water for washing with water before the dyeing as needed. The water-washed polyvinyl alcohol-based film can swell the polyvinyl alcohol-based film in addition to the dirt and anti-caking agent on the surface of the polyvinyl alcohol-based film, and can also prevent unevenness in dyeing unevenness. Extended After dyeing with iodine, it may be extended while dyeing, or may be extended with iodine. It is also possible to carry out the extension in an aqueous solution of boric acid or potassium iodide or in a water bath.

As the polarizing member, a thin polarizing member having a thickness of 15 μm or less is used. The thickness of the polarizer is preferably 12 μm, more preferably 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less, and particularly preferably 6 μm or less from the viewpoint of thickness reduction and resistance to cracking caused by thermal punching. On the other hand, the thickness of the polarizer is preferably 2 μm or more, more preferably 3 μm or more. Such a thin polarizer has a small thickness unevenness, excellent visibility, and small dimensional change, and therefore is excellent in durability against thermal punching.

The polarizer preferably contains boric acid from the viewpoint of elongation stability and optical durability. Further, the boric acid content contained in the polarizer is preferably 25% by weight or less, and preferably 20% by weight or less, and preferably 18% by weight or less, based on the total amount of the polarizer, from the viewpoint of suppressing occurrence of cracks such as through cracks. More preferably, it is 16% by weight or less. When the content of the boric acid contained in the polarizer is more than 20% by weight, even when the thickness of the polarizer is controlled to 10 μm or less, the shrinkage stress of the polarizer is increased, and cracks such as through cracks are likely to occur, which is not preferable. On the other hand, from the viewpoint of the stability of the polarizer and the optical durability, the total amount of boric acid relative to the polarizer It is preferably 10% by weight or more, more preferably 12% by weight or more.

The thin polarizer having a thickness of 15 μm or less is exemplified by the specification of Japanese Patent No. 4751486, Japanese Patent No. 4751481, Japanese Patent No. 4815544, Japanese Patent No. 5048120, and Japanese Patent No. 5587517. International public A thin polarizer such as a booklet of No. 2014/077599, a booklet of International Publication No. 2014/077636, or a thin polarizer made by the manufacturing method contained therein.

The polarizing member is preferably configured such that the optical characteristics expressed by the monomer transmittance T and the degree of polarization P satisfy the following formula P>-(10 ^0.929T-42.4 -1)×100 (but T<42.3) or P≧99.9 ( But the conditions of T≧42.3). The polarizer configured to satisfy the aforementioned conditions unambiguously has the performance required for a display for a liquid crystal television using a large display element. Specifically, it is a comparison of 1000:1 or more and a maximum luminance of 500 cd/m ² or more. For other uses, for example, it can be attached to the viewing side of the organic EL display device.

In view of the fact that the thin polarizer is capable of extending at a high magnification and improving the polarizing performance in the method of performing the stretching step and the dyeing step in the state of including the laminated body, it is preferable to obtain the method from the following method: Japanese Patent No. 4751486, Japanese Patent No. 4751481, and Japanese Patent No. 4815544, including a method of performing a step of stretching in an aqueous boric acid solution; in particular, Japanese Patent No. 4751481, Japanese Patent No. There is a description in the specification of No. 4815544, which comprises a process for assisting in the air extension step before extending in a boric acid aqueous solution. These thin polarizers can be obtained by a method comprising the steps of: extending a layer of a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) and a resin substrate for stretching in a layered state; Dyeing step. According to this method, even if the PVA-based resin layer is thin, it can be stretched without being damaged by elongation or the like by being supported by the resin substrate for stretching.

<Resin substrate>

Moreover, the resin base material (resin base material for extension) shown in FIG. 1(B) can be used for the manufacture of the said thin type polarizer. A variety of thermoplastic resins can be used as the material for forming the resin substrate. The thermoplastic resin may, for example, be an ester resin such as a polyethylene terephthalate resin, a cycloolefin resin such as a norbornene resin, an olefin resin such as polypropylene, a polyamide resin, or a polycarbonate. Resin and its copolymer resin and the like. Among them, an ester resin is preferred from the viewpoints of ease of production and cost reduction. As the ester-based thermoplastic resin substrate, a non-crystalline ester-based thermoplastic resin substrate or a crystalline ester-based thermoplastic resin substrate can be used.

<Protective film>

The material constituting the protective film is preferably one having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropic properties. For example, a polyester-based polymer such as polyethylene terephthalate or polyethylene naphthalate, a cellulose-based polymer such as diethyl cellulose or triethyl fluorenyl cellulose, or polymethyl methacrylate. A styrene-based polymer such as an acrylic polymer, a polystyrene or an acrylonitrile/styrene copolymer (AS resin), or a polycarbonate-based polymer. Further, polyethylene, polypropylene, polyolefin having a ring system or a norbornene structure, a polyolefin polymer such as an ethylene/propylene copolymer, a vinyl chloride polymer, a lanthanum or an aromatic polyamide, or the like Amidoxime polymer, quinone-based polymer, fluorene-based polymer, polyether fluorene-based polymer, polyetheretherketone-based polymer, polyphenylene sulfide-based polymer, vinyl alcohol-based polymer, and chloride Blending of a vinyl polymer, a polyvinyl butyral polymer, an arylate polymer, a polyoxymethylene polymer, an epoxy polymer or the above polymer The article or the like can be exemplified as a polymer which forms the above protective film.

Further, the protective film may contain one or more optional additives. Examples of the additives include ultraviolet absorbers, antioxidants, slip agents, plasticizers, mold release agents, coloring inhibitors, flame retardants, nucleating agents, charging inhibitors, pigments, and color formers. The content of the thermoplastic resin in the protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight and particularly preferably 70 to 97% by weight. When the content of the thermoplastic resin in the protective film is 50% by weight or less, the thermoplastic resin may not sufficiently exhibit the original high transparency and the like.

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

The retardation film may, for example, be a birefringent film formed by subjecting a thermoplastic resin film to uniaxial or biaxial stretching treatment. The visible phase difference such as the extension temperature and the stretching ratio, the film material, and the thickness are appropriately set.

The thickness of the protective film can be appropriately determined, but it is generally about 1 to 500 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. In particular, it is preferably 1 to 300 μm, preferably 5 to 200 μm, more preferably 5 to 150 μm, and particularly preferably 20 to 100 μm in the case of a thin type.

The protective film may be provided with a functional layer such as a hard coat layer, an antireflection layer, an anti-adhesion layer, a diffusion layer or an anti-glare layer on the surface of the polarizer (especially in the aspect of FIG. 1). Further, the functional layers such as the hard coat layer, the antireflection layer, the anti-adhesion layer, the diffusion layer, and the anti-glare layer may be provided separately from the protective film in addition to the protective film itself, and may be other individuals.

<intermediary layer>

The protective film and the polarizer are laminated via an interposer such as an adhesive layer, an adhesive layer, or an undercoat layer (primer layer). At this time, it is preferable to laminate both layers through the interposer in the manner of no air gap.

The layer of the agent is then formed from an adhesive. The kind of the subsequent agent is not particularly limited, and various materials can be used. The adhesive layer is not particularly limited as long as it is optically transparent, and various materials such as an aqueous system, a solvent system, a hot melt system, and an active energy ray-curing type can be used as the adhesive, but a water-based adhesive or an active energy ray-curable type can be used. The subsequent agent is preferably.

The water-based adhesive agent may, for example, be an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, or an aqueous polyester. The aqueous binder is usually used in the form of an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of a solid component.

The active energy ray-curable adhesive is an adhesive which is cured by an active energy ray such as an electron beam or an ultraviolet ray (radical hardening type or cation hardening type), and can be used, for example, in an electron beam curing type or an ultraviolet curing type. . As the active energy ray-curable adhesive, for example, a photo-radical hardening type adhesive can be used. When a photoradical-curable active energy ray-curable adhesive is used as the ultraviolet curing type, the adhesive contains a radical polymerizable compound And photopolymerization initiator.

The coating method of the subsequent agent can be appropriately selected depending on the viscosity of the adhesive and the target thickness. Examples of the coating method include, for example, a reverse coater, a gravure coater (direct, reverse or lithographic), a bar reverse coater, a roll coater, a die coater, a bar coater, and a scraper. Bar coater, etc. In addition to this, the coating may be suitably carried out by a dip coating method or the like.

Further, when the application of the above-mentioned adhesive agent is carried out using a water-based adhesive or the like, it is preferred to carry out the thickness of the finally formed adhesive layer to be 30 to 300 nm. The thickness of the above adhesive layer is more preferably 60 to 250 nm. On the other hand, when an active energy ray-curable adhesive is used, it is preferred to carry out the thickness of the adhesive layer to be 0.1 to 200 μm. It is preferably 0.5 to 50 μm, more preferably 0.5 to 10 μm.

In addition, when the polarizing member and the transparent protective film are laminated, an easy-adhesion layer may be disposed between the transparent protective film and the adhesive layer. The easy-adhesion layer may be formed of various resins having a skeleton such as a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a polyoxyn oxide system, a polyamine skeleton, a polyimine skeleton. , 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 when the easy-to-adhere layer is formed. Specifically, a stabilizer such as an adhesion-imparting agent, an ultraviolet absorber, an antioxidant, a heat-resistant stabilizer, or the like can be further used.

The easy-adhesion layer is usually disposed on the transparent protective film in advance, and the easy-contact layer side of the transparent protective film and the polarizing member are laminated by an adhesive layer. The formation of the easy-adhesion layer is known by the formation of the easy-to-adhere layer. The technique is applied to a transparent protective film and dried to carry out. The material for forming the easy-adhesion layer is usually adjusted in the form of a solution, that is, a solution which is diluted to a suitable concentration in consideration of the thickness after drying and the smoothness of coating. The thickness of the adhesive layer after drying is preferably 0.01 to 5 μm, preferably 0.02 to 2 μm, more preferably 0.05 to 1 μm. Further, although the easy-adhesion layer may be provided with a plurality of layers, it is preferable at this time that the total thickness of the easy-adhesion layer is within the above range.

The adhesive layer is formed by an adhesive. Various adhesives can be used for the adhesive, and examples thereof include a rubber-based adhesive, an acrylic-based adhesive, a polyoxygen-based adhesive, an urethane-based adhesive, a vinyl alkyl ether adhesive, and polyvinylpyrrolidine. A ketone-based adhesive, a polypropylene amide-based adhesive, a cellulose-based adhesive, or the like. The adhesive base polymer can be selected in accordance with the type of the aforementioned adhesive. Among the above-mentioned adhesives, acrylic adhesives can be suitably used from the viewpoints of excellent optical transparency, adhesion properties exhibiting appropriate wettability, cohesiveness, and adhesion, and excellent weather resistance and heat resistance.

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 it can exert a certain degree of strong adhesion to both the base film and the polyvinyl alcohol-based resin layer. For example, a thermoplastic resin or the like which is excellent in transparency, thermal stability, and elongation can be used. The thermoplastic resin may, for example, be a mixture of an acryl resin, a polyolefin resin, a polyester resin, a polyvinyl alcohol resin or the like.

<transparent layer>

The transparent layer can be formed from a variety of forming materials. The transparent layer forming material can be For example, a polyester resin, a polyether resin, a polycarbonate resin, a polyurethane resin, a polyoxyn resin, a polyamine resin, a polyimine resin, a PVA resin, and acrylic acid Resin or the like. These resin materials may be used alone or in combination of two or more. Among them, one or more selected from the group consisting of a polyurethane resin and a PVA resin is preferred, and a PVA resin is more preferable. . Further, the resin form may be either a water system or a solvent system. The resin form is preferably a water-based resin, and a PVA-based resin is preferred. Further, as the aqueous resin, an aqueous acrylic acid solution or an aqueous solution of an urethane resin can be used.

The thickness of the transparent layer is preferably 0.2 μm or more. Crack generation can be suppressed by a transparent layer having this thickness. The thickness of the transparent layer is preferably 0.5 μm or more, and more preferably 0.7 μm or more. On the other hand, when the transparent layer is too thick, the optical reliability and the water resistance are lowered, and the thickness of the transparent layer is generally 8 μm or less, preferably 6 μm or less, more preferably 5 μm or less, and still more preferably 3 μm or less. Further, the thickness of the transparent layer means the thickness formed on the aforementioned compatible layer.

From the viewpoint of crack resistance, it is preferable to reduce the orientation index of the aforementioned transparent layer. The orientation index is preferably controlled to be 0.05 or less, and preferably 0.02 or less, and no orientation (orientation index of 0.01 or less) is particularly preferable. The orientation index of the transparent layer can be determined by the method set forth in the examples.

The material forming the transparent layer is preferably one which is permeable to the polarizing member. For example, it is preferred that the material forming the transparent layer is formed of a water-soluble polyvinyl alcohol-based resin as a main component.

The polyvinyl alcohol-based resin may, for example, be polyvinyl alcohol. Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. In addition, polyvinyl alcohol The resin may, for example, be a saponified product of a copolymer of vinyl acetate and a copolymerizable monomer. When the copolymerizable monomer is ethylene, an ethylene-vinyl alcohol copolymer can be obtained. Further, examples of the copolymerizable monomer include unsaturated carboxylic acids such as maleic acid (anhydride), fumaric acid, crotonic acid, itaconic acid, (meth)acrylic acid, and esters thereof, and ethylene, propylene, and the like. - olefin, (meth) propylene sulfonic acid (sodium), sodium sulfonate (monoalkyl malate), sodium dialkyl sulfonate, N-methylol acrylamide, acrylamide alkyl An alkali metal sulfonate, an N-vinylpyrrolidone, an N-vinylpyrrolidone derivative or the like. These polyvinyl alcohol-based resins may be used alone or in combination of two or more. From the viewpoint of satisfying the heat and humidity resistance and the water resistance, it is preferred to use a polyvinyl alcohol obtained by saponifying polyvinyl acetate.

The degree of saponification of the polyvinyl alcohol-based resin may be, for example, 95% by mole or more, but from the viewpoint of satisfying moist heat resistance and water resistance, the degree of saponification is preferably 99% by mole or more, and 99.7%. More than % of the ear is preferred. The degree of saponification means that among the units which can be converted into vinyl alcohol units by saponification, the saponification is actually a ratio of singulation of vinyl alcohol units, and the residue is a vinyl ester unit. The degree of saponification can be determined in accordance with JIS K 6726-1994.

The average degree of polymerization of the polyvinyl alcohol-based resin may be, for example, 500 or more. From the viewpoint of satisfying the moist heat resistance and the water resistance, the average degree of polymerization is preferably 1,000 or more, more preferably 1,500 or more, and still more preferably 2,000 or more. The average degree of polymerization of the polyvinyl alcohol-based resin was measured in accordance with JIS-K6726.

Further, as the polyvinyl alcohol-based resin, the above polyvinyl alcohol or a modified polyvinyl alcohol-based resin having a hydrophilic functional group in a side chain of the copolymer may be used. The hydrophilic functional group may, for example, be an ethyl acetyl group or a carbonyl group. Wait. In addition, a modified polyvinyl alcohol obtained by subjecting a polyvinyl alcohol-based resin to hydroformylation, urethane, etherification, grafting, and phosphorylation can be used.

The transparent layer may be formed of a forming material that does not contain a hardenable component. For example, it can be formed from a material containing a polyvinyl alcohol-based resin (PVA-based resin) as a main component. The polyvinyl alcohol-based resin forming the transparent layer is a "polyvinyl alcohol-based resin", and may be the same as or different from the polyvinyl alcohol-based resin contained in the polarizer.

The forming material containing the polyvinyl alcohol-based resin as a main component may contain a curable component (crosslinking agent) or the like. The proportion of the polyvinyl alcohol-based resin in the transparent layer or the forming material (solid content) is preferably 80% by weight or more, more preferably 90% by weight or more, and particularly preferably 95% by weight or more. However, the aforementioned forming material is preferably free of a curable component (crosslinking agent).

As the crosslinking agent, a compound having at least two functional groups reactive with a polyvinyl alcohol-based resin can be used. For example, ethylene diamines having an alkylene group and two amine groups such as ethylenediamine, triethylenediamine, hexamethylenediamine, etc.; toluene diisocyanate, hydrogenated toluene diisocyanate, trimethylolpropane toluene Isocyanate adduct, triphenylmethane triisocyanate, methylene bis(4-phenylmethane triisocyanate, isophorone diisocyanate and the like ketone oxime block or isocyanate such as phenol block; ethylene glycol Diepoxypropyl ether, polyethylene glycol diglycidyl ether, glycerol di or triepoxypropyl ether, 1,6-hexane diol diepoxypropyl ether, trimethylol Ethylene oxides such as propane triepoxypropyl ether, diepoxypropyl aniline, diepoxypropylamine; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde; glyoxal, malondialdehyde, Succinic aldehyde, glutaraldehyde, cis-butane Dialdehydes such as enedilaldehyde and sebacaldehyde; methylol urea, methylol melamine, alkylated methylol urea, alkylated methylolated melamine, acetamide, benzoguanamine and formaldehyde Amine-formaldehyde resin such as condensate; diterpene adipate, diterpene oxalate, diammonium malonate, diterpene succinate, diammonium glutarate, diammonium phthalate, Bismuth azelaic acid, diterpene maleate, diterpenoid fumarate, diconazole dioxonium dicarboxylate, ethylene-1,2-diindole, propylene-1,3-dioxene a water-soluble diterpene such as butene-1,4-dioxane; and a divalent metal such as sodium, potassium, magnesium, calcium, aluminum, iron or nickel or a salt of a trivalent metal and an oxide thereof. Among them, an amine-formaldehyde resin and a water-soluble diterpene are preferred. The amine-formaldehyde resin is preferably a compound having a methylol group. Among them, methylol melamine which is a compound having a methylol group is particularly preferable.

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

The above-mentioned forming material is adjusted in the form of a solution, that is, a solution obtained by dissolving the polyvinyl alcohol-based resin in a solvent. Examples of the solvent include water, dimethyl hydrazine, dimethylformamide, dimethylacetamide-N-methylpyrrolidone, various glycols, alcohols, ethylenediamine, diethylenetriamine, and the like. Amines. These may be used singly or in combination of two or more. Among these, it is preferred to use an aqueous solution of water as a solvent. In the above-mentioned forming material (for example, an aqueous solution), the concentration of the polyvinyl alcohol-based resin is not particularly limited, but is 0.1 to 15% by weight, and preferably 0.5 to 10%, in consideration of coatability, stability, and the like. %.

Further, an additive may be appropriately added to the aforementioned forming material (for example, an aqueous solution). The additive may, for example, be a plasticizer, a surfactant, or the like. The plasticizer may, for example, be a polyol such as ethylene glycol or glycerin. The surfactant may, for example, be a nonionic surfactant. Further, a coupling agent such as a decane coupling agent or a titanium coupling agent, various adhesive agents, an ultraviolet absorber, an antioxidant, a heat stabilizer, a stabilizer such as a hydrolysis stabilizer, and the like can be further used.

The transparent layer can be formed by applying the above-mentioned forming material to the other surface of the polarizing member (the surface without the transparent protective film) and drying. The coating of the above-mentioned forming material is carried out so that the thickness after drying is 0.2 μm or more. The coating operation is not particularly limited, and any appropriate method can be employed. For example, a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, or a knife coating method (sweet blade coating method) may be employed. Etc.) and other means. The drying temperature is usually preferably from 60 to 120 ° C, and preferably from 70 to 100 ° C. The drying time should be 10 to 300 seconds, and more preferably 20 to 120 seconds.

<Adhesive layer>

An adhesive layer may be provided on the polarizing film to be used as a polarizing film with an adhesive layer. The adhesive layer is on the transparent layer or the polarizer side of the polarizing film, and when it has a protective film, it can be provided on the protective film. The adhesive layer of the polarizing film with the adhesive layer may be provided with a separator.

A suitable adhesive can be used for the formation of the adhesive layer, and the kind thereof is not particularly limited. Examples of the adhesive include a rubber-based adhesive, an acrylic adhesive, a polyoxygen adhesive, an urethane adhesive, and a vinyl. An alkyl ether-based adhesive, a polyvinyl alcohol-based adhesive, a polyvinylpyrrolidone-based adhesive, a polypropylene amide-based adhesive, or a cellulose-based adhesive.

Among these adhesives, those having excellent optical transparency, exhibiting appropriate wettability, cohesiveness, and adhesion properties, and having excellent weather resistance and heat resistance are preferably used. In order to exhibit such characteristics, it is preferred to use an acrylic adhesive.

The method of forming the pressure-sensitive adhesive layer can be carried out, for example, by applying the pressure-sensitive adhesive to a release-treated separator or the like, and drying the polymerization solvent or the like to form an adhesive layer. 2(A), (B) is transferred to a transparent layer or a protective film (or in the form of FIG. 2(C), that is, a protective film), or, as shown in FIG. 2(A), (B) In the aspect, the adhesive layer is applied to a transparent layer or a protective film (or in the form of FIG. 2(C), that is, a protective film), and then the polymerization solvent or the like is removed to form an adhesive layer on the polarizing member. method. Further, when the adhesive is applied, one or more solvents other than the polymerization solvent may be appropriately added.

Preferably, the release treated release member is a polyoxynitride release liner. In the step of applying the adhesive of the present invention to such a liner and drying it to form an adhesive layer, a suitable and suitable method can be employed for the purpose of drying the adhesive. A method of heating and drying the above coating film is preferably used. The heating and drying temperature should be 40 ° C ~ 200 ° C, more preferably 50 ° C ~ 180 ° C, 70 ° C ~ 170 ° C is particularly good. By setting the heating temperature to the above range, an adhesive having excellent adhesive properties can be obtained.

The drying time can be suitably and suitably used. The drying time should be 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, 10 seconds to 5 minutes. good.

Various methods can be used to form the adhesive layer. Specifically, for example, a roll coating method, a contact top coat coating method, a gravure coating method, a reverse coating method, a roll brush method, a spray coating method, a dip roll coating method, a bar coating method, a knife coating method, and a gas method are mentioned. A knife coating method, a curtain coating method, a lip mold coating method, a method using a die coating method such as a die coater, or the like.

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

When the adhesive layer is exposed, the adhesive layer may be protected by a release-treated sheet (separator) before being supplied for practical use.

The constituent material of the separator may, for example, be a plastic film such as polyethylene, polypropylene, polyethylene terephthalate or polyester film; a porous material such as paper, cloth or non-woven fabric; mesh, foamed sheet, metal foil A suitable thin film or the like, such as a laminate thereof, is preferably a plastic film 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 above-mentioned adhesive layer, and examples thereof include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, and a polymethyl group. A pentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate film, or the like.

The thickness of the separator is generally 5 to 200 μm and preferably about 5 to 100 μm. The above-mentioned separator may also be subjected to a polyfluorene-based, fluorine-based, long-chain alkyl-based or fatty acid-amide-based release agent and oxygen as needed. Release and antifouling treatment of bismuth powder, and antistatic treatment such as coating type, kneading type, and vapor deposition type. In particular, the peeling property from the adhesion of the above-mentioned adhesive layer can be further improved by appropriately performing a release treatment such as polyfluorination 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. The surface protective film usually has a substrate film and an adhesive layer, and the polarizer is protected by the adhesive layer.

The base film of the surface protective film is selected from the group consisting of isotropic or nearly isotropic film materials from the viewpoints of inspection property and management. The film material may, for example, be a polyester resin such as a polyethylene terephthalate film, a cellulose resin, an acetate resin, a polyether oxime resin, a polycarbonate resin, or a polyamide resin. A transparent polymer such as a polyimide resin, a polyolefin resin or an acryl resin. Among them, polyester resins are preferred. A laminate of one type or two or more types of film materials may be used as the base film, and an extension of the film may be used. The thickness of the base film is usually 500 μm or less, preferably 10 to 200 μm.

As the adhesive for forming the adhesive layer of the surface protective film, a (meth)acrylic polymer, a polyoxymethylene polymer, a polyester, a polyurethane, a polyamide or a polyether can be appropriately selected. A polymer such as a fluorine-based or rubber-based polymer is used as an adhesive for the base polymer. From the viewpoints of transparency, weather resistance, heat resistance and the like, an acrylic adhesive having an acrylonitrile-based polymer as a base polymer is preferred. The thickness of the adhesive layer (dry film thickness) is determined by the desired adhesive force. Usually about 1~100μm, and should be 5~50μm.

Further, in the surface protective film, the release treatment layer may be provided by a low adhesion material such as polyfluorination treatment, long-chain alkyl treatment or fluorine treatment on the opposite side of the surface of the base film on which the pressure-sensitive adhesive layer is provided.

<Other optical layers>

In the actual use of the polarizing film of the present invention, an optical film which has been laminated with other optical layers can be used. The optical layer is not particularly limited, and one or two or more layers such as a reflecting plate and a semi-transmissive plate, a phase difference plate (including 1/2 and 1/4 wavelength plates), a viewing angle compensation film, and the like may be used for formation. An optical layer such as a liquid crystal display device. In particular, a reflective polarizing film or a semi-transmissive polarizing film in which a reflecting plate or a semi-transmissive reflecting plate is laminated on the polarizing film of the present invention, and a polarizing film formed by laminating a phase difference plate on the polarizing film is particularly preferable. A film or a circularly polarizing film, a wide viewing angle polarizing film formed by laminating a viewing angle compensation film on a polarizing film, or a polarizing film formed by laminating a brightening film on a polarizing film.

The optical film in which the optical layer is laminated on the polarizing film may be formed by sequentially laminating in a process of manufacturing a liquid crystal display device or the like, but the optical film is laminated in advance to have excellent quality stability and assembly. Work, etc., have the advantage of improving the process of liquid crystal display devices. An appropriate bonding means such as an adhesive layer can be used for lamination. When the polarizing film and the other optical layer are in the following state, the optical axis thereof may be set to an appropriate arrangement angle in accordance with the phase difference characteristic of the object or the like.

The polarizing film or the optical film of the present invention can be suitably used in the formation of various devices such as a liquid crystal display device. The liquid crystal display device can be formed Implemented according to the know-how. In other words, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, a polarizing film, an optical film, and an illumination system as required, and mounting a driving circuit or the like. In the present invention, in addition to using the present invention, The polarizing film or the optical film is not particularly limited, and may be a conventional technique. As the liquid crystal cell, any type such as an IPS type or a VA type can be used, but an IPS type is particularly preferable.

A liquid crystal display device in which a liquid crystal display device in which a polarizing film or an optical film is disposed on one side or both sides of a liquid crystal cell or a liquid crystal display device such as a backlight or a reflector is used in the illumination system can be formed. At this time, the polarizing film or the optical film of the present invention may be disposed on one side or both sides of the liquid crystal cell. When polarizing films or optical films are provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, one or more layers such as a diffusion plate, an anti-glare layer, an anti-reflection film, a protective plate, a tantalum array, a lens array sheet, a light diffusing plate, and a backlight may be disposed at appropriate positions. Wait for the appropriate parts.

Example

The invention is illustrated by the following examples, but the invention is not limited by the following examples. In addition, parts and % in each case are based on weight. Hereinafter, room temperature conditions which are not specifically specified are 23 ° C 65% RH.

<Production of Optical Thin Film Laminate A0>

Corona treatment was applied to one side of a substrate of an amorphous isophthalic acid-co-polyethylene terephthalate (IPA-co-PET) film (thickness: 100 μm) having a water absorption of 0.75% and a Tg of 75 ° C. Coating on the corona-treated surface at 25 ° C in a ratio of 9:1 containing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) And an aqueous solution of PVA (polymerization degree 1200, acetylation degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gohsefimer Z200") This was dried to form a PVA-based resin layer having a thickness of 11 μm to prepare a laminate.

In the oven at 120 ° C, the obtained laminate was subjected to free end uniaxial stretching (air assisted elongation treatment) to 2.0 times in the longitudinal direction (long direction) between rolls having different circumferential speeds.

Next, the laminate was immersed in an insolubilizing bath at 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) (insolubilization treatment).

Next, the iodine concentration and the immersion time were adjusted while immersing in a dye bath at a liquid temperature of 30 ° C to bring the polarizing plate to a predetermined light transmittance. In the present embodiment, it was immersed in an aqueous iodine solution for 60 seconds (dyeing treatment) obtained by blending 0.2 part by weight of iodine with 100 parts by weight of water and blending 1.0 part by weight of potassium iodide.

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

Then, the laminate was immersed in a boric acid aqueous solution having a liquid temperature of 70 ° C (an aqueous solution obtained by blending 4 parts by weight of boric acid with 5 parts by weight of potassium iodide with respect to 100 parts by weight of water), and the rolls were different at a peripheral speed. The uniaxial extension between the cylinders makes the longitudinal (longitudinal) total extension ratio 5.5 times (water extension treatment).

Then, the laminate was immersed in a washing bath at 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 place) Reason).

Through the above, an optical film laminate A0 having a polarizing member having a thickness of 5 μm was obtained.

<Production of Optical Thin Film Laminate A1>

In the process of producing the optical film laminate A0, the optical thin film laminate A1 was produced in the same manner as in the production method of the optical thin film laminate A0 except that the boric acid blended with the aqueous boric acid solution in the water-extended treatment was changed to 3.5 parts by weight. . The thickness of the obtained polarizer was 5 μm.

<Production of Optical Thin Film Laminate A2>

In the process of producing the optical film laminate A0, the optical thin film laminate A2 was produced in the same manner as in the production method of the optical thin film laminate A0 except that the boric acid blended with the aqueous solution of the boric acid in the water-extended treatment was changed to 4.5 parts by weight. . The thickness of the obtained polarizer was 5 μm.

<Production of Optical Thin Film Laminate D>

In the process of producing the optical film laminate A0, an optical film laminate D was produced in the same manner as in the production method of the optical film laminate A0 except that a PVA-based resin layer having a thickness of 15 μm was formed. The thickness of the obtained polarizer was 7 μm.

<Production of polarizer E>

A polyvinyl alcohol film having an average degree of polymerization of 2,400, a degree of saponification of 99.9 mol%, and a thickness of 30 μm was immersed in warm water of 30 ° C for 60 seconds to swell. Subsequently, the film was immersed in an aqueous solution of 0.3% by weight of iodine/potassium iodide (weight ratio = 0.5/8), and the film was dyed while being extended to 3.5 times. Thereafter, the solution was extended to a total stretching ratio of 6 times in a 65 ° C aqueous solution of borate. After extension, oven at 40 ° C The film was dried for 3 minutes to obtain a PVA-based polarizer E. The thickness of the obtained polarizer was 12 μm.

<Production of polarizer F>

A polyvinyl alcohol film having an average degree of polymerization of 2,400, a degree of saponification of 99.9 mol%, and a thickness of 75 μm was immersed in warm water of 30 ° C for 60 seconds to swell. Subsequently, the film was immersed in an aqueous solution of 0.3% by weight of iodine/potassium iodide (weight ratio = 0.5/8), and the film was dyed while being extended to 3.5 times. Thereafter, the solution was extended to a total stretching ratio of 6 times in a 65 ° C aqueous solution of borate. After stretching, it was dried in an oven at 40 ° C for 3 minutes to obtain a PVA-based polarizer F. The thickness of the obtained polarizer was 23 μm.

(production of protective film)

Protective film: It was used after corona treatment was applied to the easily-treated surface of a (meth)acrylic resin film having a thickness of 40 μm and having a lactone ring structure.

(Applicable to the manufacture of protective film adhesives)

40 parts by weight of N-hydroxyethyl acrylamide (HEAA) with acrylonitrile 60 parts by weight of the morpholine (ACMO) was mixed with 3 parts by weight of a photopolymerization initiator "IRGACURE 819" (manufactured by BASF Corporation) to prepare an ultraviolet curable adhesive.

(Polyvinyl alcohol-based forming material A)

A polyvinyl alcohol resin having a degree of polymerization of 2,500 and a degree of saponification of 99.0 mol% was dissolved in pure water to prepare an aqueous solution having a solid concentration of 4% by weight.

(Polyvinyl alcohol-based forming material B)

A polyvinyl alcohol resin having a polymerization degree of 500 and a degree of saponification of 99.0 mol% was dissolved in pure water to prepare an aqueous solution having a solid concentration of 4% by weight.

(Polyvinyl alcohol-based forming material C)

A polyvinyl alcohol resin having a degree of polymerization of 2,500 and a degree of saponification of 89.0 mol% was dissolved in pure water to prepare an aqueous solution having a solid concentration of 4% by weight.

(Polyvinyl alcohol-based forming material D)

A polyvinyl alcohol resin having a degree of polymerization of 2,500 and a degree of saponification of 99.7 mol% was dissolved in pure water to prepare an aqueous solution having a solid concentration of 4% by weight.

(Polyvinyl alcohol-based forming material E)

100 parts of a polyvinyl alcohol resin having a degree of polymerization of 2,500 and a degree of saponification of 99.7 mol%, and 5 parts of an additive methylol melamine (manufactured by DIC Corporation, "WATER SOL: S-695") were dissolved in pure water to prepare An aqueous solution having a solid concentration of 4% by weight was obtained.

(Composition of acrylic forming material A)

N-hydroxyethyl acrylamide (manufactured by Xingren Co., Ltd., trade name "HEAA") 20 parts

Ethyl urethane acrylate (manufactured by Nippon Synthetic Chemical Co., Ltd., trade name "UV-1700B") 80 parts

Photoradical polymerization initiator (2-methyl-1-(4-methylthiophenyl)-2- Lolinylpropan-1-one, manufactured by BASF Corporation, trade name "IRGACURE 907") 3 parts

Photosensitizer (diethyl 9-oxosulfur , manufactured by Nippon Kayaku Co., Ltd., trade name "KAYACURE DETX-S")

(Modulation of active energy ray-curable forming material)

The acrylic forming material was mixed and stirred at 50 ° C for 1 hour to prepare various active energy ray-curable forming materials.

(irradiation active energy line)

The active energy ray is irradiated with visible light (a metal halide lamp sealed with gallium): Light HAMMER 10 manufactured by Fusion UV Systems, Inc., valve: V valve, peak illuminance: 1600 mW/cm ² , and integrated irradiation amount 1000/mJ/cm ² ( Wavelength 380~440nm). In addition, the illuminance of visible light was measured using a Sola-Check system manufactured by Solatell.

Reference example 1 <Production of single-sided protective polarizing film A>

The ultraviolet curable adhesive is applied to the surface of the polarizer of the optical film laminate A0 so that the thickness of the adhesive layer after curing is 0.5 μm, and the protective film is bonded thereto, followed by irradiation activity. The energy line hardens the adhesive. Next, the amorphous PET substrate was peeled off to produce a one-side protective polarizing film A0 using a thin polarizer. The optical characteristics of the obtained one-side protective polarizing film A0 were 42.8% of light transmittance and 99.99% of polarization degree.

Reference example 2~4 <Production of single-sided protective polarizing films A1, A2, D>

In Reference Example 1, a single-sided protective polarizing film A1, A2 or the like was produced in the same manner as in the production method of the one-side protective polarizing film A0 except that the optical film laminates A1, A2 or D were used instead of the optical film laminate A0. D. The optical characteristics of the obtained one-side protective polarizing film A1, A2 or D were 42.8% of light transmittance and 99.99% of polarization degree.

Reference example 5 <Production of single-sided protective polarizing film E>

On the one side surface of the polarizer E, the ultraviolet curable adhesive is applied so that the thickness of the adhesive layer after hardening becomes 0.5 μm. The protective film was bonded, and then the active energy ray was irradiated to harden the adhesive to obtain a one-side protective polarizing film E. The optical characteristics of the obtained one-side protective polarizing film E were 42.8% of light transmittance and 99.99% of polarization degree.

Reference example 6 <Production of single-sided protective polarizing film F>

In Reference Example 5, a one-side protective polarizing film F was produced in the same manner as in Reference Example 5 except that the polarizer F was used instead of the polarizer E. The optical characteristics of the obtained one-side protective polarizing film F were 42.8% of light transmittance and 99.99% of polarization degree.

Example 1 <Production of single-sided protective polarizing film A0 with transparent layer: Corresponding to Fig. 2(A)>

In the polarizing surface of the one-side protective polarizing film A0 obtained in Reference Example 1 (the polarizing surface on which the transparent protective film is not provided), the thickness (excluding the compatible layer) after drying is 0.8 μm, and the wire rod is used. After coating the polyethylene pure-form forming material A adjusted to 25 ° C by a coater, it was dried by hot air at 80 ° C for 30 seconds to prepare a one-side protective polarizing film A0 with a transparent layer.

Examples 2 to 10 and Comparative Examples 2 and 3

In the first embodiment, the one-side protective polarizing film A0, A1 or A2 with a transparent layer was produced in the same manner as in Example 1 except that the material of the transparent layer and the thickness of the transparent layer were changed as shown in Table 1.

Further, the transparent layer of Comparative Example 2 is as follows.

The active energy ray-curable forming material (acrylic forming material A) was applied to a thickness of 1 μm using a wire bar coater, and then irradiated with an active energy ray under a nitrogen atmosphere to produce a single layer with a transparent layer. Side protection polarizing film A0. The obtained one-side protective polarizing film A0 with a transparent layer The optical characteristics were 42.8% transmittance and 99.99% polarization.

Examples 11, 12, Comparative Examples 4, 5 <Production of one-side protective polarizing film D to F with transparent layer>

In the first embodiment, the one-side protection with a transparent layer was produced in the same manner as in Example 1 except that the type of the one-side protective polarizing film, the type of the transparent layer forming material, and the thickness of the transparent layer were changed as shown in Table 1. Polarized film D to F. The optical characteristics of the obtained one-side protective polarizing films D to F with a transparent layer were 42.8% of light transmittance and 99.99% of polarization degree.

Comparative example 1 (Production of water-based adhesive)

At a temperature of 30 ° C, the polyvinyl alcohol-based resin with respect to the ethyl acetonitrile group (average degree of polymerization: 1200, degree of saponification: 98.5 mol%, degree of acetylation: 5 mol%) 100 parts of 50 parts of methylol melamine were dissolved in pure water to prepare an aqueous solution having a solid content adjusted to a concentration of 3.7%. To 100 parts of the aqueous solution, 18 parts of an aqueous alumina colloid solution (having an average particle diameter of 15 nm and a solid concentration of 10% and a positive charge) was added to prepare a water-based adhesive.

(production of polarizing film)

Corona treatment was applied to one side of a substrate of a crystalline isophthalic acid-co-polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and a Tg of 75 ° C. An aqueous solution containing polyvinyl alcohol (degree of polymerization: 2,500, saponification degree: 99.0 mol%) was applied to the corona-treated surface at ° C and dried to form a PVA-based resin layer having a thickness of 1 μm to prepare a laminate. Next, the polarizer surface of the polarizing film A0 is protected on one side (the protective film is not provided) The water-based adhesive was applied to the surface of the polarizer so that the film thickness was 0.1 μm, and the film was bonded to the PVA resin layer of the laminate, and then dried at 60 ° C for 1 minute. Thereafter, the PET film of the substrate was peeled off to prepare a one-side protective polarizing film with a transparent layer.

Reference example 7 <Production of Unilateral Protective Polarizing Film (Laminated) B>

On the surface of the polarizer of the optical film laminate A0, the ultraviolet curable adhesive was applied so that the thickness of the adhesive layer after curing was 0.5 μm, and the protective film was bonded thereto. Further, the ultraviolet curable adhesive is applied to the surface of the protective film so that the thickness of the adhesive layer after curing is 0.5 μm, and after bonding the protective film, ultraviolet rays are applied as an active energy ray to make an adhesive. hardening.

Next, the amorphous PET substrate was peeled off to produce a one-side protective polarizing film (layered) B using a thin polarizer. The optical characteristics of the obtained one-side protective polarizing film (layered layer) B were 42.8% of light transmittance and 99.99% of polarization degree.

Example 13 <Making a single-sided protective polarizing film with a transparent layer (layered): Corresponding to Figure 2(B)>

The polarizer surface of the one-side protective polarizing film (layer) B obtained in Reference Example 7 (the polarizer surface on which the protective film is not provided) was coated by a wire bar coater so as to have a thickness of 0.7 μm after drying. After the polyvinyl alcohol-based material A was adjusted to 25 ° C, it was dried by hot air at 60 ° C for 1 minute to prepare a one-side protective polarizing film (layered) B with a transparent layer. The optical characteristics of the obtained one-side protective polarizing film (layered layer) B with a transparent layer were 42.8% of light transmittance and 99.99% of polarization degree.

Example 14 <Production of double-sided protective polarizing film C with transparent layer: Corresponding to Fig. 2(C)>

The polarizer surface of the one-side protective polarizing film A0 obtained in Reference Example 1 (the polarizer surface on which the protective film is not provided) was coated to have a thickness of 0.7 μm after drying by a wire bar coater. After the polyvinyl alcohol-based material A was formed at ° C, it was dried by hot air at 60 ° C for 1 minute to prepare a one-side protective polarizing film A0 having a transparent layer.

On the surface of the transparent layer of the one-side protective polarizing film A0 having the transparent layer, the ultraviolet curable adhesive is applied so that the thickness of the adhesive layer after curing is 0.5 μm, and the protective film is bonded thereto. Ultraviolet rays are irradiated as an active energy ray to harden the adhesive. The optical characteristics of the obtained double-sided protective polarizing film C with a transparent layer were 42.8% of light transmittance and 99.99% of polarization degree.

Reference Example 8 <Production of double-sided protective polarizing film C>

In the polarizing surface of the one-side protective polarizing film A0 obtained in Reference Example 1 (the polarizing surface of the protective film), the ultraviolet curing type was applied so that the thickness of the adhesive layer after curing was 0.5 μm. After bonding the protective film, the ultraviolet rays are irradiated as an active energy ray to cure the adhesive. The optical characteristics of the obtained double-sided protective polarizing film C with a transparent layer were 42.8% of light transmittance and 99.99% of polarization degree.

The polarizing films obtained in the above examples and comparative examples were subjected to the following evaluations. The results are shown in Table 1. The evaluation was carried out in the following manner with respect to the polarizing film of the prepared adhesive layer.

<Determination of boric acid content in polarizer>

For the polarizers obtained in the examples and the comparative examples, a Fourier transform infrared spectrophotometer (FTIR) (trade name "SPECTRUM 2000" manufactured by Perkin Elmer Co., Ltd.) was used, and the total reflection attenuation spectrometry (ATR) measurement method using the polarized light as the measurement light was used. The intensity of the boric acid spike (665 cm ^-1 ) and the intensity of the reference peak (2941 cm ^-1 ) were measured. The boric acid amount index was calculated from the obtained boric acid spike intensity and the reference peak intensity, and the boric acid content (% by weight) was determined from the calculated boric acid amount index by the following formula.

(boric acid amount index) = (strength of boric acid spike 665 cm ^-1 ) / (reference intensity of peak 2941 cm ^-1 )

(Boronic acid content (% by weight)) = (boric acid amount index) × 5.54 + 4.1

<Modulation of acrylic polymer>

A monomer mixture of 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl methacrylate was fed into a 4-neck flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a cooler. Further, 100 parts of the monomer mixture (solid content), 0.1 part of 2,2 ' -azobisisobutyronitrile of a polymerization initiator, and ethyl acetate were fed together, and nitrogen gas was introduced and nitrogen substitution was carried out while stirring slowly. The liquid temperature in the flask was maintained at about 60 ° C and polymerization was carried out for 7 hours. Thereafter, ethyl acetate was added to the obtained reaction liquid to prepare an acrylic polymer solution having a solid content of 30% and a weight average molecular weight of 1.4 million.

(adhesive composition) modulation)

100 parts of the solid component of the above acrylic polymer solution, blended with trimethylolpropane xylene diisocyanate (manufactured by Mitsui Chemicals Co., Ltd.: Takenate D110N) 0.1 part, 0.3 parts of dibenzoguanidine peroxide, and γ-glycidyl Oxypropylpropyl 0.075 parts of oxydecane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-403) was prepared to prepare an acrylic adhesive solution.

(formation of adhesive layer)

Next, the acrylic adhesive solution was uniformly applied onto the surface of a polyethylene terephthalate film (separator film) treated with a polyfluorene-based release agent by a jet knife coater at 155 ° C. The air circulating type constant temperature oven was dried for 2 minutes to form an adhesive layer having a thickness of 20 μm on the surface of the separator film.

<Production of polarizing film with adhesive layer>

Next, the transparent layer of the polarizing film obtained in each example (but the reference examples 1 to 7 are the polarizer side, and the reference example 8 is the protective film on one side) were bonded to the release treatment formed on the release sheet (separator). The adhesive layer of the surface is used to form a polarizing film with an adhesive layer.

<Confirmation of thickness of compatible layer>

The thickness of the compatible layer was measured by TOF-SIMS equipped with a gas cluster ion gun. The film thickness of the transparent layer (excluding the phase of the polarizing layer) of the polarizing film (sample) was calculated from the correct film thickness calculated in advance by a scanning electron microscope. From the transparent layer side of the polarizing film (sample) toward the polarizer side, the depth profile was observed while etching with argon clusters, and "BO ₂ ^- ions" (ion intensity) derived from the polarizer were extracted. A graph as shown in Fig. 3 was prepared for the depth (nm) and "BO ₂ ^- ion" (ion intensity) from the side of the transparent layer. So that the film thickness of the transparent layer is obtained from the electron microscope as "B", from the side of a polarizer "BO ₂ ^- ion" begins to decrease toward the side of the transparent layer is "A" and "distance between AB" is the thickness of the compatible layer. As a result of measuring the film thickness by a scanning electron microscope in Example 1, the thickness of the polarizing member was 5.0 μm, and the thickness of the transparent layer was 0.8 μm. Further, the ionic strength was measured while etching from the side of the transparent layer by TOF-SIMS, and as a result, a graph as shown in Fig. 3 was obtained. FIG 3 with respect to the transparent layer in the "BO ₂ ^- ionic" strength of 0.8, the polarizer member "BO ₂ ^- ionic" strength of 3.5. Further, as shown in FIG. 3, a gradient of "BO ₂ ^- ion" intensity is formed between ABs. When the "inter-AB distance" is converted from the etching rate of the argon cluster, the thickness of the phase-soluble layer is 0.12 μm. Further, when using FTIR examples contained in the transparent layer side measurement "BO ₂ ^- ionic" strength of 0.8 parts of boric acid, the boric acid content of 4%. On the other hand, TOF-SIMS in "BO ₂ ^- ionic" strength of a boric acid content of 3.5 based polarizer obtained in FTIR prior to forming the transparent layer, a boric acid content of 16%. It is thus shown that in the phase of the polarizer, the boric acid is present in the form of a gradient (i.e., the phase of the soluble layer corresponds to a lower concentration of boric acid having a lower concentration of boric acid than other portions of the polarizer).

<Directivity index of transparent layer>

The measurement apparatus used was a Fourier transform infrared spectrophotometer (FT-IR) (manufactured by Perkin Elmer Co., Ltd., trade name "SPECTRUM 2000"). The polarized light was used as the measurement light, and the surface of the transparent layer was evaluated by an ATR (Attenuated Total Reflection) measurement method. The calculation of the orientation function is performed in the following order. The measurement was carried out in a state where the measured polarized light was 0° and 90° with respect to the extending direction of the polarizing member. The intensity at which the obtained spectrum was 2941 cm ^-1 was calculated according to the following formula. Further, the intensity I of the following line as the reference peak at 3330cm ^-1, a value used 2941cm ^-1 / ^{3330cm -1} of. In addition, when f=1, it will be completely oriented, and when f=0, it will become random. Further, the peak of 2941 cm ^-1 is said to be the absorption of the vibration of "-CH ₂ -". In the main chain of the material for the transparent layer, when there is no "-CH ₂ -", it can be evaluated in place of the spectrum of the vibration of the main chain.

(formula) f=(3<cos ² θ>-1)/2=(1-D)/[c(2D+1)]

However, c=(3cos ² β-1)/2β=90deg f=-2×(1-D)/(2D+1)θ: molecular chain ‧ extension direction β: molecular chain ‧ transition dipole moment D=(I _⊥ )/(I _∥ )

(The more PVA is oriented, the larger the D value.)

I _⊥ : The intensity at which the polarized light is incident and measured in the vertical direction; I _∥ : the intensity at which the polarized light is incident in the direction parallel to the extending direction and measured.

<Dimensional change rate>

The direction of the absorption axis of the obtained polarizing film with the adhesive layer was longitudinally cut, cut to a length of 100 mm × 100 mm, and attached to an alkali-free glass having a thickness of 1.3 mm, and then placed in an environment of 85 ° C for 500 hours. Thereafter, the size of the polarizing film was measured. The dimensional change rate % in the absorption axis direction was calculated from the obtained result according to the following formula.

{(length after input) - (length before input)} / (length before input) × 100 (%)

The dimensional change rate is based on the case where no transparent layer is provided (Reference Examples 1 to 8), and the reduction ratio of the dimensional change ratio of the polarizing film having the same structure is determined by the following criteria. The dimensional change suppression effect can be calculated according to the following formula.

100-{(dimension change rate) / (reference Dimensional change rate) × 100} (%) benchmark 対

×: The suppression effect of the dimensional change is less than 10%.

△: The suppression effect of the dimensional change was 10% or more and less than 15%.

○: The suppression effect of the dimensional change was 15% or more and less than 20%.

◎: The suppression effect of the dimensional change was 20% or more.

<Crack resistance>

The polarizing film of the obtained adhesive layer was cut into a length of 400 mm × a width of 708 mm (absorption axis direction of 400 mm) and a length of 708 mm × width of 400 mm (absorption axis direction of 708 mm), and then attached to the direction of the orthogonal polarizer. A sample was prepared on both sides of an alkali-free glass having a length of 402 mm × a width of 710 mm and a thickness of 1.3 mm. After the sample was placed in an oven at 95 ° C for 250 hours, it was taken out and visually confirmed whether or not cracks occurred in the polarizing film of the adhesive layer. In this test, 10 samples were taken for one sample, and the number of cracked samples was counted and judged based on the following criteria.

×: The number of crack occurrences was six or more.

△: The number of crack occurrences is 3 to 5 pieces.

○: The number of crack occurrences is 1 to 2 pieces.

◎: No crack occurred.

<Heat and Heat Resistance: Rate of Change of Polarization (Optical Reliability Test)>

The obtained polarizing film with the adhesive layer was cut into a size of 25 mm × 50 mm (the absorption axis direction was 50 mm). The one-side protective polarizing film (sample) was placed in a constant temperature and humidity machine at 85 ° C / 85% RH for 150 hours. The polarization degree of the unilateral protective polarizing film before and after the input was measured using an integral sphere-branch spectroscopic transmittance measuring instrument (Dot-3c of Murakami Color Technology Research Institute), and the rate of change of the degree of polarization (%) was determined. (1-(polarization after input/polarization before input)).

Further, the degree of polarization P is obtained by applying the following light transmittance to the following formula, that is, the light transmittance when two identical polarizing films are bonded in such a manner that the transmission axes of the two are parallel. Parallel transmittance: Tp); and, by transmission of both The transmittance of the axis when it is superposed (straight transmittance: Tc).

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

Each light transmittance is represented by a Y value obtained by correcting the visual sensitivity by a 2 degree field of view (C light source) of JIS Z8701 by using 100% of fully polarized light obtained by a Glan Taylor polarizer.

Table 1 shows the rate of change of the degree of polarization while determining the rate of change based on the following criteria.

○: The rate of change in the degree of polarization was 0.5% or less.

△: The rate of change in the degree of polarization is more than 0.5% and is 5.0% or less.

×: The rate of change in the degree of polarization is greater than 5.0%.

In Table 1, WS represents methylol melamine: Water Sol S-695 (manufactured by DIC Corporation).

1‧‧‧ polarizer

2‧‧‧Transparent layer

3‧‧‧Resin substrate

10‧‧‧Polarized film

A‧‧‧ polarizer thickness

B‧‧‧Composition layer thickness

X‧‧‧compatible layer

Claims (12)

A polarizing film having a transparent layer on at least one surface of a polarizing member, wherein the polarizing member contains a polyvinyl alcohol-based resin and has a thickness of 15 μm or less; and the transparent layer side of the polarizing member has a transparent layer And a thickness B of the polarizing member and a thickness B of the aforementioned compatibility layer satisfy a general formula: (100 × B / A) ≧ 1. The polarizing film according to claim 1, wherein the phase of the compatibility layer and the portion of the polarizing member other than the aforementioned phase of the polarizing member are lower than the concentration of the lower boric acid. A polarizing film having a transparent layer on at least one surface of a polarizing member, wherein the polarizing member contains a polyvinyl alcohol-based resin and has a thickness of 15 μm or less; and the transparent layer side of the polarizing member has a low concentration of boric acid The layer has a relatively low concentration of boric acid compared to the other portions of the polarizer; and the thickness A of the polarizer and the thickness C of the boric acid low concentration layer satisfy the general formula: (100 × C / A) ≧ 1. The polarizing film according to any one of claims 1 to 3, wherein the transparent layer has a thickness of 0.2 μm or more. The polarizing film according to any one of claims 1 to 3, wherein the transparent layer has a thickness of 6 μm or less. The polarizing film according to any one of claims 1 to 3, wherein the transparent layer has a directivity index of 0.05 or less. The polarizing film according to any one of claims 1 to 3, wherein the transparent layer is a formed material of a material, and the forming material contains a polyvinyl alcohol-based resin. The polarizing film of claim 7, wherein the polyvinyl alcohol-based resin has a degree of saponification of 99 mol% or more and an average degree of polymerization of 2,000 or more. The polarizing film according to any one of claims 1 to 3, wherein the polarizing member is configured to have an optical characteristic represented by a single light transmittance T and a degree of polarization P satisfying a condition of the following formula: P>-(10 ^{0.929T) -42.4} -1) × 100 (but T <42.3); or P ≧ 99.9 (but T ≧ 42.3). The polarizing film according to any one of claims 1 to 3, which has a protective film. A polarizing film with an adhesive layer, comprising the polarizing film and the adhesive layer according to any one of claims 1 to 10. An image display device comprising: the polarizing film of any one of claims 1 to 10 or a polarizing film of the adhesive layer of claim 11.