JP6797077B2 - Polarizing film with adhesive layer, its manufacturing method, and image display device - Google Patents

Description

The present invention relates to a polarizing film with an adhesive layer and a method for producing the same. The polarizing film with an adhesive layer can form an image display device such as a liquid crystal display device (LCD) or an organic EL display device alone or as an optical film in which the polarizing film is laminated.

In a liquid crystal display device or the like, it is indispensable to arrange polarizing elements on both sides of a liquid crystal cell due to the image forming method, and generally, a polarizing film is attached. When the polarizing film is attached to the liquid crystal cell, an adhesive is usually used. Further, in order to reduce the loss of light, the polarizing film and the liquid crystal cell are usually adhered to each other by using an adhesive. In such a case, since there is an advantage that a drying step is not required to fix the polarizing film, the pressure-sensitive adhesive is polarized light with a pressure-sensitive adhesive layer previously provided as a pressure-sensitive adhesive layer on one side of the polarizing film. Films are commonly used. A release film is usually attached to the pressure-sensitive adhesive layer of the polarizing film with the pressure-sensitive adhesive layer.

A pressure-sensitive adhesive containing a base polymer and a cross-linking agent is usually used to form the pressure-sensitive adhesive layer. As the base polymer, an acrylic polymer is used as an award, and as a cross-linking agent, an isocyanate-based cross-linking agent is used as an award.

Further, from the viewpoint of thinning, a polarizing film with an adhesive layer using a single protective polarizing film in which a protective film is provided only on one side of the polarizer has been proposed. However, a polarizing film with an adhesive layer using a single protective polarizing film is subjected to a harsh environment such as a thermal shock (for example, a 250-hour test at 95 ° C.), and the shrinkage stress of the polarizer on the side where the protective film is provided. Due to the difference in contraction stress of the polarizer on the opposite side of the protective film, excessive stress is generated inside the polarizer so that it penetrates the entire surface from minute cracks of several hundred μm in the direction of the absorber's absorption axis. There is a problem that various cracks are likely to occur, including through cracks. That is, the single-sided protective polarizing film with an adhesive layer did not have sufficient durability in the harsh environment.

From the viewpoint of suppressing the occurrence of the through cracks and reducing the layer thickness and weight, a protective layer made of a water-soluble film-forming composition (polyvinyl alcohol-based resin composition) may be provided on at least one surface of the polarizer. It has been proposed (Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-043858

As described above, when a protective layer (anchor coat layer) formed from the polyvinyl alcohol-based resin composition is provided, and further, a pressure-sensitive adhesive layer containing an isocyanate-based cross-linking agent is provided on the protective layer for protection. The protective layer and the pressure-sensitive adhesive layer have good anchoring power due to the reaction between the hydroxyl group derived from the polyvinyl alcohol-based resin in the layer and the isocyanate group derived from the isocyanate-based cross-linking agent in the pressure-sensitive adhesive layer.

However, the pressure-sensitive adhesive layer containing the isocyanate-based cross-linking agent is formed after the pressure-sensitive adhesive layer is formed in order to have hardness corresponding to dent resistance and processability and to secure anchoring force. It took a certain amount of aging time to ship. Further, since the pressure-sensitive adhesive composition containing an isocyanate-based cross-linking agent undergoes a self-cross-linking reaction, it has a pot life as the pressure-sensitive adhesive composition, which makes it difficult to handle. On the other hand, in the pressure-sensitive adhesive composition not containing the isocyanate-based cross-linking agent, the anchoring property with the anchor coat layer formed from the polyvinyl alcohol-based resin composition was not sufficiently satisfactory.

The present invention is a polarizing film with a pressure-sensitive adhesive layer having an anchor coat layer containing a polarizer and an aqueous resin and a pressure-sensitive adhesive layer in this order, even if the pressure-sensitive adhesive layer does not contain an isocyanate-based cross-linking agent. An object of the present invention is to provide a polarizing film with an adhesive layer, which has good anchoring force between the anchor coat layer and the adhesive layer.

Another object of the present invention is to provide a method for producing the polarizing film with an adhesive layer. The present invention also relates to an image display device having the polarizing film with an adhesive layer.

As a result of diligent studies, the inventors of the present application have found that the above problems can be solved by the following polarizing film with an adhesive layer or the like, and have reached the present invention.

That is, the present invention is a polarizing film with an adhesive layer having a polarizer, an anchor coat layer, and an adhesive layer in this order.
The anchor coat layer is formed of an aqueous resin composition containing a compound (a) having at least one primary alcohol capable of reacting with an aqueous resin and a hydroxyl group at the molecular terminal.
The pressure-sensitive adhesive layer relates to a polarizing film with a pressure-sensitive adhesive layer, which is formed from a pressure-sensitive adhesive composition containing a base polymer having a hydroxyl group and a mercapto group-containing silane coupling agent.

In the polarizing film with an adhesive layer, at least one selected from a polyvinyl alcohol-based resin, a polyurethane-based resin, and an oxazoline group-containing polymer can be used as the aqueous resin. As the water-based resin, a polyvinyl alcohol-based resin is preferable. Further, the polyvinyl alcohol-based resin preferably has a saponification degree of 96 mol% or more and an average degree of polymerization of 2000 or more.

In the polarizing film with an adhesive layer, the aqueous resin composition preferably contains 0.2 to 20 parts by weight of the compound (a) with respect to 100 parts by weight of the aqueous resin.

In the polarizing film with an adhesive layer, methylolmelamine can be preferably used as the compound (a).

In the polarizing film with an adhesive layer, the anchor coat layer preferably has a thickness of 0.05 μm or more and 6 μm or less.

In the polarizing film with an adhesive layer, a (meth) acrylic polymer having a hydroxyl group can be used as the base polymer having a hydroxyl group.

In the polarizing film with a pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition preferably contains 0.01 to 5 parts by weight of the mercapto group-containing silane coupling agent with respect to 100 parts by weight of the base polymer having a hydroxyl group. ..

In the polarizing film with a pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition can contain a cross-linking agent. The cross-linking agent preferably contains a cross-linking agent (b) that does not react with the hydroxyl group. As the cross-linking agent (b) that does not react with the hydroxyl group, a peroxide is preferable.

In the polarizing film with a pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition contains 0.01 to 2 parts by weight of a cross-linking agent (b) that does not react with the hydroxyl group with respect to 100 parts by weight of the base polymer having a hydroxyl group. Is preferable.

In the polarizing film with an adhesive layer, the polarizing element preferably has a thickness of 15 μm or less.

In the polarizing film with an adhesive layer, the polarizing element has optical characteristics represented by a simple substance transmittance T and a degree of polarization P according to the following formula.
P>-(10 ^0.929 T ^-42.4 -1) x 100 (however, T <42.3), and
It is preferable that the configuration is such that the condition of P ≧ 99.9 (however, T ≧ 42.3) is satisfied.

In the polarizing film with an adhesive layer, a protective film can be provided on at least one side of the polarizing element.

In the polarizing film with an adhesive layer, a separator can be laminated on the adhesive layer.

The present invention is a method for producing the polarizing film with an adhesive layer.
A water-based resin composition containing a compound (a) having at least one water-based resin and a primary alcohol capable of reacting with a hydroxyl group at the molecular end is applied onto the polarizer, and then dried and anchored. The process of forming the coat layer and
A step of forming a pressure-sensitive adhesive layer from a pressure-sensitive adhesive composition containing a base polymer having a hydroxyl group and a mercapto group-containing silane coupling agent on the anchor coat layer.
The present invention relates to a method for producing a polarizing film with an adhesive layer, which comprises the above.

The present invention also relates to an image display device having the polarizing film with an adhesive layer.

The polarizing film with an adhesive layer of the present invention has an anchor coat layer containing a polarizer and an aqueous resin and an adhesive layer in this order.
The anchor coat layer contains a compound (a) having at least one primary alcohol capable of reacting with a hydroxyl group at the end of the molecule, for example, methylol melamine, and the pressure-sensitive adhesive layer is a mercapto group-containing silane coupling. Contains the agent. The terminal primary alcohol such as methylol melamine in the anchor coat layer reacts with the water-based resin (for example, polyvinyl alcohol-based resin) of the anchor coat layer, while the mercapto group-containing silane cup in the pressure-sensitive adhesive layer. It is thought to react with the silanol group of the ring agent. Furthermore, when the anchor coat layer is directly provided on the polarizer, the terminal primary alcohol such as methylol melamine in the anchor coat layer is derived from the polyvinyl alcohol-based resin in the polarizer. It is thought to react with the hydroxyl group. Further, the silanol group of the mercapto group-containing silane coupling agent is considered to react with the hydroxyl group derived from the base polymer in the pressure-sensitive adhesive layer. Further, it is considered that the mercapto group-containing silane coupling agent can form a sulfide bond by self-condensation by the reaction between the mercapto groups (-SH, thiol group) in the pressure-sensitive adhesive layer and enhance the cross-linking of the pressure-sensitive adhesive layer. .. In this way, the anchor coat layer and each material in the pressure-sensitive adhesive layer are bonded by reacting, so that even if the pressure-sensitive adhesive layer does not contain an isocyanate-based cross-linking agent, the anchor coat layer and the above-mentioned The pressure-sensitive adhesive layer is considered to have good anchoring properties.

This is an example of a schematic cross-sectional view of the polarizing film with an adhesive layer of the present invention. This is an example of a schematic cross-sectional view of the polarizing film with an adhesive layer of the present invention. This is an example of a schematic cross-sectional view of the polarizing film with an adhesive layer of the present invention.

The polarizing films 10, 11 and 12 with an adhesive layer of the present invention will be described below with reference to FIGS. 1 to 3. The polarizing films 10, 11 and 12 with the pressure-sensitive adhesive layer have a polarizing element 1, an anchor coat layer 2 containing an aqueous resin, and a pressure-sensitive adhesive layer 3 in this order. In the polarizing films 10 and 11 with the pressure-sensitive adhesive layer of the present invention, as shown in FIGS. 1 and 2, the anchor coat layer 2 formed from the water-based resin composition containing the water-based resin is directly provided on the polarizer 1. be able to. Further, as shown in FIGS. 2 and 3, protective films 5 and 5'can be provided on one side or both sides of the polarizer 1. In FIG. 2, in the polarizing film 10 with an adhesive layer, a case where the protective film 5 is provided on the side of the polarizing element 1 opposite to the side on which the anchor coat layer 2 is provided is illustrated. Further, in FIG. 3, in the polarizing film 10 with an adhesive layer, protective films 5 and 5'are provided on both sides of the polarizing element 1, and an anchor coat layer 2 is provided on the side of the protective film 5'. Is illustrated. Although not shown in FIGS. 2 and 3, the polarizer 1 and the protective film 5 are laminated via an intervening layer such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer). Further, although not shown, the easy-adhesive layer and the adhesive layer can be laminated by providing the easy-adhesive layer on the protective films 5 and 5'or applying an activation treatment.

Further, in the polarizing films 10 and 11 with an adhesive layer of the present invention, as shown in FIGS. 1 to 3, a separator 4 can be provided on the adhesive layer 3. When the polarizing film 11 with an adhesive layer has a protective film 5, as shown in FIGS. 2 and 3, a surface protective film can be provided on the protective film 5.

<Polarizer>
The polarizer is not particularly limited, and various polarizers can be used. As the polarizer, for example, a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymerization system partially saponified film, and a bicolor property of iodine or a bicolor dye are used. Examples thereof include a uniaxially stretched film by adsorbing a substance, a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrogenated product of polyvinyl chloride. Among these, a polarizer made of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally 2 to 25 μm.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be prepared, for example, by dyeing the polyvinyl alcohol-based film by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times the original length. it can. If necessary, it can be immersed in an aqueous solution of potassium iodide or the like, which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. In addition to being able to clean the surface of the polyvinyl alcohol film and blocking inhibitors by washing the polyvinyl alcohol film with water, it also has the effect of preventing non-uniformity such as uneven dyeing by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. It can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

As the polarizer, a thin polarizer having a thickness of 15 μm or less can be used. The thickness of the polarizer is preferably 12 μm, more preferably 10 μm or less, further 8 μm or less, further 7 μm or less, and further 6 μm or less from the viewpoint of thinning and crack resistance due to thermal shock. On the other hand, the thickness of the polarizer is preferably 2 μm or more, more preferably 3 μm or more. Such a thin polarizing element has less uneven thickness, excellent visibility, and less dimensional change, so that it has excellent durability against thermal shock.

As a thin polarizer with a thickness of 15 μm or less, typically
Japanese Patent No. 4751486,
Japanese Patent No. 4751481
Patent No. 4815544,
Japanese Patent No. 5048120,
Japanese Patent No. 5587517,
International Publication No. 2014/07759 Pamphlet,
International Publication No. 2014/077636 Pamphlet,
The thin polarizing film (polarizer) described in the above, or the thin polarizing film (polarizer) obtained from the manufacturing method described therein can be mentioned.

The polarizer has optical characteristics represented by a simple substance transmittance T and a degree of polarization P of the following equation P> − (10 ^0.929 T ^-42.4 -1) × 100 (where T <42.3) and It is preferable that the configuration is such that the condition of P ≧ 99.9 (however, T ≧ 42.3) is satisfied. A polarizing film configured to satisfy the above conditions has uniquely the performance required for a display for a liquid crystal television using a large display element. Specifically, the contrast ratio is 1000: 1 or more and the maximum brightness is 500 cd / m ² or more. As another application, for example, it is bonded to the visual side of an organic EL display device.

The thin polarizing film can be stretched at a high magnification and the polarization performance can be improved even in a manufacturing method including a step of stretching in a laminated state and a step of dyeing. Those obtained by a production method including a step of stretching in an aqueous boric acid solution as described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544 are preferable, and particularly described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544. It is preferably obtained by a production method including a step of auxiliary stretching in the air before stretching in a certain boric acid aqueous solution. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a resin base material for stretching in a laminated state and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching because it is supported by the stretching resin base material.

<Protective film>
As the material constituting the protective film, those having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropic property and the like are preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples thereof include based polymers and polycarbonate polymers. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamides, imide polymers, and sulfone polymers. , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, allylate polymer, polyoxymethylene polymer, epoxy polymer, or the above. Polymer blends and the like are also examples of polymers that form the protective film. These protective films are usually attached to the polarizer by an adhesive layer. Further, the protective film uses a thermosetting resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, silicone, etc. or an ultraviolet curable resin, and these are applied to a polarizer and cured. Can be formed by

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

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

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

A functional layer such as a hard coat layer, an antireflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer can be provided on the surface of the protective film to which the polarizer is not adhered. The functional layers such as the hard coat layer, the antireflection layer, the sticking prevention layer, the diffusion layer and the antiglare layer can be provided on the protective film itself, or may be separately provided separately from the protective film. it can.

<Intervening layer>
The protective film and the polarizer are laminated via an intervening layer such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer). At this time, it is desirable that both are laminated without an air gap by an intervening layer.

The adhesive layer is formed by the adhesive. The type of adhesive is not particularly limited, and various adhesives can be used. The adhesive layer is not particularly limited as long as it is optically transparent, and various forms such as water-based, solvent-based, hot-melt-based, and active energy ray-curable type are used as the adhesive. Alternatively, an active energy ray-curable adhesive is suitable.

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

The active energy ray-curable adhesive is an adhesive whose curing proceeds by active energy rays such as electron beam and ultraviolet rays (radical curing type, cationic curing type). For example, in the form of electron beam curing type and ultraviolet curing type. Can be used. As the active energy ray-curable adhesive, for example, a photoradical curable adhesive can be used. When a photoradical curable type active energy ray curable adhesive is used as an ultraviolet curable type, the adhesive contains a radical polymerizable compound and a photopolymerization initiator.

Further, when an aqueous adhesive or the like is used, the coating of the adhesive is preferably performed 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 250 nm. On the other hand, when an active energy ray-curable adhesive is used, the thickness of the adhesive layer is preferably 0.1 to 200 μm. It is more preferably 0.5 to 50 μm, still more preferably 0.5 to 10 μm.

When laminating the polarizer and the protective film, an easy-adhesion layer can be provided between the protective film and the adhesive layer.

<Anchor coat layer>
The anchor coat layer contains an aqueous resin. The anchor coat layer can be formed, for example, by applying an aqueous resin composition containing an aqueous resin to a polarizer. As the water-based resin, for example, at least one selected from a polyvinyl alcohol-based resin, a polyurethane-based resin, and an oxazoline group-containing polymer can be used. Among these, when the anchor coat layer is directly formed on the polarizer as shown in FIGS. 1 and 2, the polyvinyl alcohol-based resin is preferable as the aqueous resin from the viewpoint of suppressing the occurrence of through cracks. On the other hand, when the anchor coat layer is formed on the protective film as shown in FIG. 3, a polyurethane resin or an oxazoline group-containing polymer is preferable as the aqueous resin from the viewpoint of coating film forming property and wettability with respect to the protective film. ..

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol. Polyvinyl alcohol is obtained by saponification of polyvinyl acetate. Examples of the polyvinyl alcohol-based resin include a saponified product of a copolymer of vinyl acetate and a monomer having copolymerizability. When the monomer having copolymerizability is ethylene, an ethylene-vinyl alcohol copolymer can be obtained. 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; ethylene, propylene, and the like. α-olefin, (meth) allylsulfonic acid (soda), sodium sulfonic acid (monoalkylmalate), sodium disulfonic acid alkylmalate, N-methylolacrylamide, acrylamidealkylsulfonic acid alkali salt, N-vinylpyrrolidone, N- Examples thereof include vinylpyrrolidone derivatives. These polyvinyl alcohol-based resins may be used alone or in combination of two or more. From the viewpoint of controlling the amount of heat of crystal melting of the anchor coat layer to 30 mj / mg or more to satisfy the heat resistance to moisture and water, polyvinyl alcohol obtained by saponifying polyvinyl acetate is preferable.

For example, a polyvinyl alcohol-based resin having a saponification degree of 95 mol% or more can be used, but from the viewpoint of satisfying moisture heat resistance and water resistance, the saponification degree is preferably 96 mol% or more, and is 99. It is preferably mol% or more, and more preferably 99.5 mol% or more. The degree of saponification represents the ratio of units that are actually saponified to vinyl alcohol units among the units that can be converted to vinyl alcohol units by saponification, and the residue is a vinyl ester unit. The degree of saponification can be determined according to JIS K 6726-1994.

For example, a polyvinyl alcohol-based resin having an average degree of polymerization of 500 or more can be used, but from the viewpoint of satisfying the moist heat resistance and water resistance of the anchor coat layer, the average degree of polymerization is preferably 1000 or more. , 1500 or more is preferable, and further 2000 or more is preferable. The average degree of polymerization of the polyvinyl alcohol-based resin is measured according to JIS-K6726.

Further, 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 a copolymer thereof can be used. Examples of the hydrophilic functional group include an acetoacetyl group and a carbonyl group. In addition, modified polyvinyl alcohol obtained by acetalizing, urethanizing, etherifying, grafting, or phosphorifying a polyvinyl alcohol-based resin can be used.

As the polyurethane-based resin, an emulsion of the polyurethane-based resin can be used. Further, as the polyurethane resin emulsion, a self-emulsified one can be used without using an emulsifier.

As the polyurethane-based resin, for example, a one-component type obtained by a double addition reaction of a polymer polyol and an isocyanate compound can be used. As the one-component polyurethane resin, for example, a polyether polyurethane resin, a polyester polyurethane resin, or the like can be used. As the polyurethane resin, those having a hydroxyl group remaining are preferable. Specifically, for example, a lacquer type polyurethane resin can be mentioned. The polyurethane resin can be formed into a film simply by drying and removing a solvent or water.

The polyether polyurethane resin is generally obtained by a double addition reaction of a polyether polyol and an isocyanate compound. The polyether polyol is obtained by adding an alkylene oxide to one or more of the polyhydric alcohols by ring-opening polymerization. The polyester-based polyurethane resin is generally obtained by a double addition reaction of a polyester polyol and an isocyanate compound. Polyester polyol is obtained by polycondensing a polyhydric alcohol and a polybasic acid. Further, the polymer polyol such as a polyether polyol or a polyether polyol preferably has a number average molecular weight of 400 to 3000, and more preferably 500 to 2000. As the polymer polyol such as a polyether polyol and a polyester polyol, one type may be used alone, or a copolymer using two or more types may be used.

As the isocyanate compound, an aromatic, aromatic aliphatic, aliphatic, or alicyclic isocyanate usually used for polyurethane can be appropriately used. Further, as the isocyanate compound, an adduct, a dimer, a trimer of the above-mentioned isocyanate compound, a polymer thereof and the like may be used. Further, as the isocyanate compound, a modified isocyanate in which a part of the isocyanate is uretized, uretidioneized, or carbodiimidized can also be used.

When the polyurethane resin is dispersed in water, a method is known in which the resin is forcibly emulsified and dispersed using an emulsifier to prepare the resin. Further, a self-emulsified product obtained by introducing an anionic group, a cation group or a nonionic group of a water-dispersible hydrophilic group into the resin can be used. Further, an ionic polymer complex can be used.

Examples of the polyurethane resin emulsion include the Adeka Bontiter HUX series manufactured by Asahi Denka Kogyo Co., Ltd., which is self-emulsified without using an emulsifier. Specific examples of the water-based urethane resin include Superflex series manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Takelac W-6020 manufactured by Mitsui Chemicals Polyurethane Co., Ltd., and the like.

As the epoxy resin, an epoxy resin emulsion can be used. When the epoxy resin is dispersed in water, a method is known in which the resin is forcibly emulsified and dispersed using an emulsifier to prepare the resin. Examples of the epoxy resin include ADEKA EM series manufactured by ADEKA Corporation and Serokiside 2021P manufactured by Daicel Corporation.

Examples of the oxazoline group-containing polymer include a polymer containing a main chain composed of an acrylic skeleton or a styrene skeleton and having an oxazoline group in the side chain of the main chain. Among the above, an oxazoline group-containing acrylic polymer containing a main chain composed of an acrylic skeleton and having an oxazoline group in the side chain of the main chain is preferable.

Examples of the oxazoline group include 2-oxazoline group, 3-oxazoline group, 4-oxazoline group and the like, and among these, 2-oxazoline group is preferable. The 2-oxazoline group is generally represented by the following general formula (1).

（式中、Ｒ^１〜Ｒ^４は、それぞれ独立に、水素原子、ハロゲン原子、アルキル基、アラルキル基、フェニル基、又は、置換フェニル基を示す。）

(In the formula, R ^{1 to} R ⁴ independently represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, a phenyl group, or a substituted phenyl group.)

Further, the oxazoline group-containing polymer may have a polyoxyalkylene group in addition to the oxazoline group.

The number average molecular weight of the oxazoline group-containing polymer is preferably 5,000 or more, more preferably 10,000 or more, and usually 1,000,000 or less. If the number average molecular weight is lower than 5,000, the strength of the anchor layer may be insufficient to cause cohesive fracture, and the anchoring force may not be improved. If the number average molecular weight is higher than 1,000,000, workability may be inferior. Further, the oxazoline group-containing polymer has an oxazoline value of, for example, 1,500 gsolid / eq. It is preferably 1,200 g solid / eq. More preferably: Oxazoline titer is 1,500 g solid / eq. If it is larger than this, the amount of oxazoline groups contained in the molecule will be small, and the anchoring power may not be improved.

In the oxazoline group-containing polymer, the oxazoline group reacts with the hydroxyl group contained in the pressure-sensitive adhesive composition at a relatively low temperature. Therefore, if the oxazoline group-containing polymer is contained in the anchor coat layer, the functional group in the pressure-sensitive adhesive layer It reacts with such things and can adhere firmly.

Specific examples of the oxazoline group-containing polymer include oxazoline group-containing acrylic polymers such as Epocross WS-300, Epocross WS-500, and Epocross WS-700 manufactured by Nippon Shokubai Co., Ltd., for example, manufactured by Nippon Shokubai Co., Ltd. Examples thereof include oxazoline group-containing acrylic / styrene-based polymers such as Epocross K-1000 series and Epocross K-2000 series, which can be used alone or in combination of two or more.

The anchor coat layer of the present invention is formed from an aqueous resin composition containing the aqueous resin as a main component, and the aqueous resin composition contains a primary alcohol capable of reacting with a hydroxyl group at the molecular end. It contains at least one compound (a). By introducing the compound (a) into the anchor coat layer, as described above, the reaction with the mercapto group-containing silane coupling agent and the base polymer having a hydroxyl group in the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer. Is advanced, and the anchoring force between the anchor coat layer and the pressure-sensitive adhesive layer can be improved.

The aqueous resin preferably does not have a functional group having reactivity with the hydroxyl group of the compound (a) and a primary alcohol capable of reacting with the hydroxyl group, and among the above-exemplified aqueous resins, the polyvinyl alcohol-based resin is preferable. Is preferable, and in particular, an unmodified polyvinyl alcohol resin is preferably used. Alternatively, when an unmodified polyvinyl alcohol resin is used, the hydrophilic functional group involved in the modification is adherent in relation to the hydroxyl group of the compound (a) and a reactive primary alcohol. Those having a lower reactivity than the functional group (silanol group) of the mercapto group-containing silane coupling agent in the agent composition are preferable.

The compound (a) is preferably blended in a proportion of, for example, 0.2 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the aqueous resin. It is preferable that the ratio of the compound (a) is 0.2 parts by weight or more in order to improve the anchoring force. The ratio of the compound (a) is preferably 1 part by weight or more, and more preferably 3 parts by weight or more. On the other hand, as the proportion of the compound (a) increases, the water resistance and appearance (appearance confirmed as unevenness in the polarizing film) deteriorate, so that the proportion of the compound (a) is 20 parts by weight or less. It is preferable, more preferably 10 parts by weight or less, and more preferably 7 parts by weight or less. The ratio of the compound (a) is determined by the type of the base polymer having a hydroxyl group and the mercapto group-containing silane coupling agent used in the pressure-sensitive adhesive composition.

The proportion of the water-based resin in the anchor coat layer or the water-based resin composition (solid content) is preferably 80% by weight or more, more preferably 90% by weight or more, and further preferably 95% by weight or more.

As the compound (a), a compound having at least one primary alcohol at the molecular terminal can be preferably used. As the compound, for example, methylol urea, methylol melamine, amino condensate with an alkylating methylol urea and formaldehyde - include formaldehyde resins. Among these, an amino-formaldehyde resin having a methylol group, and among them, methylol melamine is preferable.

Further, a compound having a functional group capable of reacting with a hydroxyl group other than the compound (a) can be used. For example, a compound having an amino group at the end of the molecule can be mentioned. Examples of the compound include alkylene dihydrs having two alkylene groups and two amino groups such as ethylene dihydric acid, triethylene dihydric acid, and hexamethylene dihydric acid; hydrazine; adipic acid dihydrazide, dihydrazide oxalic acid, dihydrazide malonic acid, dihydrazide succinic acid, and glutaric acid. Dihydrazides such as dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide; ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4 − Examples include water-soluble dihydrazines such as dihydrazines. Of these, hydrazine is preferred. A compound having an amino group at the molecular end contains, for example, a hydroxyl group-containing monomer as a monomer unit when the base polymer of the pressure-sensitive adhesive composition has a hydroxyl group (when the base polymer is a (meth) acrylic polymer). It is suitable for

Further, examples of the compound having a functional group capable of reacting with a hydroxyl group other than the compound (a) include tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethyl propane tolylene diisocyanate adduct, and triphenylmethane triisocyanate. Methylenebis (4-phenylmethane triisocyanate, isophorone diisocyanate and isocyanates such as these ketooxime block products or phenol block products; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerindi or triglycidyl ether, 1,6- Epoxys such as hexanediol diglycidyl ether, trimethylpropan triglycidyl ether, diglycidyl aniline, diglycidyl amine; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butylaldehyde; glioxal, malondialdehyde, succindialdehyde, Dialdehydes such as glutaldialdehyde, maleindialdehyde, phthaldialdehyde; amino-formaldehyde resins such as alkylated methylolated melamine, acetoguanamine, condensate of benzoguanamine and formaldehyde; further sodium, potassium, magnesium, calcium, aluminum , Divalent metals such as iron and nickel, or salts of trivalent metals and oxides thereof. Among these, amino-aldehyde resin and water-soluble dihydrazine are preferable.

A compound having a functional group capable of reacting with a hydroxyl group other than the compound (a) can be used from the viewpoint of improving water resistance and controlling the elastic modulus, and the ratio thereof is based on 100 parts by weight of the aqueous resin. , 20 parts by weight or less, preferably 10 parts by weight or less, and more preferably 5 parts by weight or less.

The aqueous resin composition is prepared as a solution in which the aqueous resin is dissolved in a solvent. Examples of the solvent include water, dimethyl sulfoxide, dimethylformamide, and dimethylacetamide N-methylpyrrolidone. 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 water-based resin in the water-based resin composition (for example, an aqueous solution) is not particularly limited, but is 0.1 to 15% by weight, preferably 0.5, in consideration of coatability, standing stability, and the like. It is 10% by weight.

A compound other than the compound (a) may be added to the aqueous resin composition (for example, an aqueous solution). For example, a surfactant and the like can be mentioned. Examples of the surfactant include nonionic surfactants. Further, various tackifiers, ultraviolet absorbers, antioxidants, heat-resistant stabilizers, hydrolysis-resistant stabilizers and other stabilizers can be blended.

The thickness of the anchor coat layer is preferably 0.05 μm, more preferably 0.2 μm or more, and the thickness of the anchor coat layer is preferably 0.5 μm or more, further 0. It is preferably 7 μm or more. In particular, when a polyvinyl alcohol-based resin is used as the water-based resin, the thickness of the anchor coat layer is preferably 0.2 μm or more, and the anchor coat layer having the thickness causes cracks due to thermal shock. Can be suppressed. On the other hand, if the anchor coat layer becomes too thick, the optical reliability and water resistance deteriorate. Therefore, the thickness of the anchor coat layer is preferably 6 μm or less, further 5 μm or less, further 3 μm or less, and further 2 μm or less. Is preferable.

The anchor coat layer can be formed by applying the aqueous resin composition to the other side of the polarizer (the side having no protective film) and drying it. The water-based resin composition is applied so as to have a thickness after drying (preferably 0.2 μm or more and 6 μm or less). The coating operation is not particularly limited, and any suitable method can be adopted. For example, various means such as a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, and a knife coating method (comma coating method, etc.) can be adopted.

<Adhesive layer>
The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a base polymer having a hydroxyl group and a mercapto group-containing silane coupling agent. An appropriate pressure-sensitive adhesive having a hydroxyl group can be used for forming the pressure-sensitive adhesive layer, and the type thereof is not particularly limited. As adhesives, rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinylpyrrolidone adhesives, polyacrylamide adhesives, Examples include cellulose-based adhesives. Various base polymers can be used depending on these pressure-sensitive adhesives.

The proportion of the base polymer having a hydroxyl group in the pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition (solid content) is preferably 80% by weight or more, further 90% by weight or more, and further 95% by weight. The above is preferable.

Among these adhesives, those having excellent optical transparency, exhibiting appropriate wettability, cohesiveness and adhesiveness, and excellent weather resistance and heat resistance are preferably used. Acrylic adhesives are preferably used to exhibit such characteristics. A (meth) acrylic polymer is used as the base polymer of the acrylic pressure-sensitive adhesive. The (meth) acrylic polymer usually contains an alkyl (meth) acrylate as a main component as a monomer unit. In addition, (meth) acrylate means acrylate and / or methacrylate, and has the same meaning as (meth) of the present invention.

Examples of the alkyl (meth) acrylate constituting the main skeleton of the (meth) acrylic polymer include those having a linear or branched alkyl group having 1 to 18 carbon atoms. For example, the alkyl group includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an amyl group, a hexyl group, a cyclohexyl group, a heptyl group, a 2-ethylhexyl group, an isooctyl group, a nonyl group and a decyl group. Examples thereof include a group, an isodecyl group, a dodecyl group, an isomyristyl group, a lauryl group, a tridecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group and the like. These can be used alone or in combination. The average number of carbon atoms of these alkyl groups is preferably 3 to 9.

The (meth) acrylic polymer used in the present invention preferably contains a hydroxyl group-containing monomer as a monomer unit. The hydroxyl group-containing monomer has a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group, and has a hydroxyl group. Specific examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxy (meth) acrylate. Hydroxyalkyl (meth) acrylate and (4-hydroxymethylcyclohexyl)-such as hexyl, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, etc. Examples include methyl acrylate.

The (meth) acrylic polymer contains alkyl (meth) acrylate as a main component in the weight ratio of all constituent monomers, and the ratio of the hydroxyl group-containing monomer in the (meth) acrylic polymer is the weight ratio of all constituent monomers. , 0.01 to 15%, more preferably 0.03 to 10%, and further preferably 0.05 to 7%.

Further, among the (meth) acrylic polymers, one type having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group for the purpose of improving adhesiveness and heat resistance. The above copolymerization monomers can be introduced by copolymerization.

Examples of the copolymerization monomer include carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; maleic anhydride. , Acid anhydride group-containing monomers such as itaconic anhydride; caprolactone adduct of acrylic acid; styrene sulfonic acid and allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, Examples thereof include sulfonic acid group-containing monomers such as sulfopropyl (meth) acrylate and (meth) acryloyloxynaphthalene sulfonic acid; and phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate.

In addition, (N-substituted) amides such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylolpropane (meth) acrylamide. Monomer; (meth) Alkylaminoalkyl monomeric acid such as aminoethyl acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate; (meth) acrylic (Meta) alkoxyalkyl-based monomers such as methoxyethyl acid and ethoxyethyl (meth) acrylate; N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N-( Meta) Succinimide-based monomers such as acryloyl-8-oxyoctamethylene succinimide and N-acryloylmorpholine; maleimide-based monomers such as N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide and N-phenylmaleimide; N-methylitacon Italone-based monomers such as imide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide, etc. As an example of the monomer of.

Further, as modified monomers, vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazin, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholin, N- Vinyl-based monomers such as vinylcarboxylic acid amides, styrene, α-methylstyrene, N-vinylcaprolactam; cyanoacrylate-based monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; Glycol-based acrylic ester monomers such as (meth) polyethylene glycol acrylate, (meth) polypropylene glycol acrylate, (meth) methoxyethylene glycol acrylate, (meth) methoxypolypropylene glycol acrylate; (meth) tetrahydrofurfuryl acrylate, Acrylic acid ester-based monomers such as fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate can also be used. Further, isoprene, butadiene, isobutylene, vinyl ether and the like can be mentioned.

Further, examples of the copolymerizable monomer other than the above include a silane-based monomer containing a silicon atom. Examples of the silane-based monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxysilane. , 8-Vinyloctyloxydecyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane and the like.

Examples of the copolymerization monomer include tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, and neo. Pentyl glycol di (meth) acrylate, trimethyl propantri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate , Caprolactone-modified dipentaerythritol Hexa (meth) Acrylate and other (meth) acrylic acids and polyhydric alcohols such as esterified products such as (meth) acryloyl groups and vinyl groups and other unsaturated double bonds having two or more unsaturated double bonds. Polyester (meth) acrylates and epoxys (meth) acrylates and epoxys in which two or more unsaturated double bonds such as (meth) acryloyl groups and vinyl groups are added as functional groups similar to the monomer components to the skeletons of sex monomers, polyesters, epoxys, urethanes, etc. Meta) acrylate, urethane (meth) acrylate and the like can also be used.

The ratio of the copolymerization monomer (other than the hydroxyl group-containing monomer) in the (meth) acrylic polymer is not particularly limited, but the weight ratio of all the constituent monomers is about 0 to 20%, about 0.1 to 15%, and so on. Further, it is preferably about 0.1 to 10%.

Among these copolymerizable monomers (other than hydroxyl group-containing monomers), carboxyl group-containing monomers are preferably used from the viewpoint of adhesiveness and durability. When a carboxyl group-containing monomer is contained as the copolymerization monomer, the proportion thereof is preferably 0.05 to 10% by weight, more preferably 0.1 to 8% by weight, and further preferably 0.2 to 6% by weight. ..

As the (meth) acrylic polymer of the present invention, those having a weight average molecular weight in the range of 500,000 to 3,000,000 are usually used. Considering durability, particularly heat resistance, it is preferable to use one having a weight average molecular weight of 700,000 to 2.7 million. Further, it is preferably 800,000 to 2.5 million. If the weight average molecular weight is less than 500,000, it is not preferable in terms of heat resistance. Further, when the weight average molecular weight is larger than 3 million, a large amount of diluting solvent is required to adjust the viscosity for coating, which is not preferable because it increases the cost. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

For the production of such a (meth) acrylic polymer, known production methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations can be appropriately selected. Further, the obtained (meth) acrylic polymer may be any of a random copolymer, a block copolymer, a graft copolymer and the like.

The polymerization initiator, chain transfer agent, emulsifier and the like used for radical polymerization are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the (meth) acrylic polymer can be controlled by the amount of the polymerization initiator and the chain transfer agent used, and the reaction conditions, and the amount of the (meth) acrylic polymer used is appropriately adjusted according to these types.

Further, the pressure-sensitive adhesive composition of the present invention contains a mercapto group-containing silane coupling agent in addition to the base polymer having a hydroxyl group (for example, a (meth) acrylic polymer). Examples of the mercapto group-containing silane coupling agent include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane, and β-mercaptomethylphenylethyl. Examples thereof include compounds having a mercapto group such as trimethoxysilane, mercaptomethyltrimethoxysilane, 6-mercaptohexyltrimethoxysilane, and 10-mercaptodecyltrimethoxysilane.

Further, as the mercapto group-containing silane coupling agent, an oligomer-type mercapto group-containing silane coupling agent having two or more alkoxysilyl groups in the molecule is preferable. Specific examples thereof include X-41-1805, X-41-1818, and X-41-1810 manufactured by Shin-Etsu Chemical Co., Ltd. These mercapto group-containing silane coupling agents are preferable because they are hard to volatilize and have a plurality of alkoxysilyl groups, which is effective in improving durability. Here, the oligomer type refers to a polymer having a dimer or more and less than a 100-mer of the monomer, and the weight average molecular weight of the oligomer-type silane coupling agent is preferably about 300 to 30,000.

The number of alkoxysilyl groups in the oligomer-type mercapto group-containing silane coupling agent may be two or more in the molecule, and the number is not limited. The amount of the alkoxy group in the oligomer-type mercapto group-containing silane coupling agent is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, and 20 to 40% by weight in the silane coupling agent. It is more preferably% by weight.

The type of the alkoxy group is not limited, and examples thereof include alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, and hexyloxy. Among these, methoxy and ethoxy are preferable, and methoxy is more preferable. It is also preferable that one molecule contains both methoxy and ethoxy.

In the case of a mercapto group (-SH), for example, the mercapto group content of the mercapto group-containing silane coupling agent is preferably 1000 g / mol or less, and more preferably 800 g / mol or less. More preferably, it is 500 g / mol or less. The lower limit of the mercapto equivalent is not particularly limited, but is preferably 200 g / mol or more, for example.

The mercapto group-containing silane coupling agent may be used alone or in combination of two or more, but the overall content is the base polymer having the hydroxyl group (for example, the above-mentioned base polymer having a hydroxyl group). (Meta) acrylic polymer) 0.001 to 5 parts by weight, more preferably 0.01 to 3 parts by weight, further preferably 0.02 to 2 parts by weight, 0.05 to 1 part by weight, based on 100 parts by weight. Parts by weight are particularly preferred.

Further, a silane coupling agent other than the mercapto group-containing silane coupling agent can be added to the pressure-sensitive adhesive composition of the present invention. Other coupling agents include 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene). Amino group-containing silane coupling agents such as propylamine and N-phenyl-γ-aminopropyltrimethoxysilane, (meth) acrylic group-containing silanes such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane. Examples thereof include a coupling agent and an isocyanate group-containing silane coupling agent such as 3-isocyanatepropyltriethoxysilane.

A silane coupling agent other than the mercapto group-containing silane coupling agent can be added within a range that does not impair the effects of the present invention, and the amount used is not particularly limited, but for example, for an adherend. From the viewpoint of adhesion, it can be used in the range of 3 parts by weight or less, further 2 parts by weight or less, and further 1 part by weight or less with respect to 100 parts by weight of the pressure-sensitive adhesive composition. .. Adhesion can be improved by using a silane coupling agent other than the mercapto group. However, since a silane coupling agent other than the mercapto group can also impart reworkability, the adhesion tends to deteriorate when the amount added is large.

Further, the pressure-sensitive adhesive composition of the present invention may contain a cross-linking agent. The cross-linking agent may be used alone or in combination of two or more. The content of the cross-linking agent as a whole is preferably 2 parts by weight or less, more preferably 1.5 parts by weight or less, and further 1 part by weight with respect to 100 parts by weight of the base polymer having a hydroxyl group. The following is preferable.

In the pressure-sensitive adhesive composition of the present invention, it is preferable that the cross-linking agent contains a cross-linking agent (b) that does not react with a hydroxyl group. The cross-linking agent (b) that does not react with the hydroxyl group may be used in combination with an isocyanate-based cross-linking agent, but is suitable in an embodiment that does not contain an isocyanate-based cross-linking agent. When the pressure-sensitive adhesive composition of the present invention does not contain an isocyanate-based cross-linking agent, there is no problem in handling the pot life. The cross-linking agent (b) that does not react with the hydroxyl group does not particularly need to be aged until it reaches a predetermined gel fraction after the pressure-sensitive adhesive layer is formed, and the gel fraction 80 from the initial stage of forming the pressure-sensitive adhesive layer. It is possible to produce a hard material of% or more. Furthermore, since cross-linking is carried out in the pressure-sensitive adhesive layer with a cross-linking agent (b) that does not react with the hydroxyl group, the hydroxyl group of the base polymer efficiently reacts with the silanol group of the mercapto group-containing silane coupling agent. It is considered that the gel content of the pressure-sensitive adhesive layer can be hardened to 80% or more from the initial stage.

The cross-linking agent (b) may be used alone or in combination of two or more, but the total content is 100 parts by weight of the base polymer having a hydroxyl group. On the other hand, the amount of the cross-linking agent (b) is preferably 0.01 to 2 parts by weight, more preferably 0.04 to 1.5 parts by weight, further preferably 0.05 to 1 part by weight, and further. More preferably, it is 0.4 to 0.6 parts by weight. It is appropriately selected within this range in order to adjust workability, reworkability, crosslink stability, peelability and the like.

Peroxide can be preferably used as the cross-linking agent (b).

As a method for measuring the amount of peroxide decomposition remaining after the reaction treatment, for example, HPLC (high performance liquid chromatography) can be used.

More specifically, for example, about 0.2 g of the pressure-sensitive adhesive composition after the reaction treatment is taken out, immersed in 10 ml of ethyl acetate, extracted by shaking at 120 rpm for 3 hours at 25 ° C. with a shaker, and then at room temperature. Let stand for 3 days. Next, 10 ml of acetonitrile was added, and the mixture was shaken at 120 rpm at 25 ° C. for 30 minutes, and about 10 μl of the extract obtained by filtering with a membrane filter (0.45 μm) was injected into HPLC for analysis, and after the reaction treatment. It can be the amount of peroxide.

As the peroxide, any peroxide that generates radically active species by heating or light irradiation to promote cross-linking of the base polymer of the pressure-sensitive adhesive composition can be appropriately used, but in consideration of workability and stability. It is preferable to use a peroxide having a half-life temperature of 80 ° C. to 160 ° C. for 1 minute, and more preferably to use a peroxide having a half-life temperature of 90 ° C. to 140 ° C.

Examples of the peroxide that can be used include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.) and di (4-t-butylcyclohexyl) peroxydicarbonate (1). Minute half-life temperature: 92.1 ° C., di-sec-butylperoxydicarbonate (1 minute half-life temperature: 92.4 ° C.), t-butylperoxyneodecanoate (1 minute half-life temperature: 103) .5 ° C.), t-hexyl peroxypivalate (1 minute half-life temperature: 109.1 ° C.), t-butyl peroxypivalate (1 minute half-life temperature: 110.3 ° C.), dilauroyl peroxide (1 minute half-life temperature: 110.3 ° C.) 1 minute half temperature: 116.4 ° C), di-n-octanoyl peroxide (1 minute half temperature: 117.4 ° C), 1,1,3,3-tetramethylbutylperoxy-2-ethyl Hexanoate (1 minute half-life temperature: 124.3 ° C.), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130. 0 ° C.), t-Butylperoxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.) And so on. Among them, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.) and dilauroyl peroxide (1 minute half-life temperature: 116.) Since the cross-linking reaction efficiency is particularly excellent. 4 ° C.), dibenzoylperoxide (1 minute half-life temperature: 130.0 ° C.) and the like are preferably used.

The half-life of peroxide is an index showing the decomposition rate of peroxide, and means the time until the residual amount of peroxide is halved. The decomposition temperature for obtaining a half-life at an arbitrary temperature and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc. For example, "Organic peroxide catalog 9th edition" of Nippon Oil & Fats Co., Ltd. (May 2003) ”and so on.

As the cross-linking agent other than the cross-linking agent (b), an organic cross-linking agent or a polyfunctional metal chelate can be used. Examples of the organic cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, and imine-based cross-linking agents. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinated to an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti and the like. Can be mentioned. Examples of the atom in the organic compound having a covalent bond or a coordination bond include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound.

The amount of the cross-linking agent other than the cross-linking agent (b) is preferably controlled so that a hard material having a gel fraction of 80% or more from the initial stage of forming the pressure-sensitive adhesive layer can be produced. For example, a cross-linking agent other than the cross-linking agent (b) can be used in a range of 2 parts by weight or less with respect to 100 parts by weight of the pressure-sensitive adhesive composition, further 1 part by weight or less, and further 0.5 parts by weight. It can be included in the following range. In particular, when an isocyanate-based cross-linking agent is used as a cross-linking agent other than the cross-linking agent (b), the amount used is controlled within a range that does not require aging. The isocyanate-based cross-linking agent is preferable from the viewpoint of ensuring an anchoring force on an adherend such as a film, and is also preferable from the viewpoint of hardening the pressure-sensitive adhesive layer and suppressing a dimensional change of the polarizing film. Furthermore, it is particularly preferable to use an isocyanate-based cross-linking agent and a cross-linking agent (b) that does not react with a hydroxyl group in combination because a stronger anchoring force can be obtained.

Further, the pressure-sensitive adhesive composition of the present invention may contain an alkali metal salt, a polyether-modified silicone compound, and other known additives, for example, a polyether compound of polyalkylene glycol such as polypropylene glycol, and coloring. Powders such as agents and pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, light stabilizers, UV absorbers, polymerization prohibited Agents, inorganic or organic fillers, metal powders, particles, foils and the like can be added as appropriate depending on the intended use. Further, a redox system to which a reducing agent is added may be adopted within a controllable range.

A pressure-sensitive adhesive layer is formed by the pressure-sensitive adhesive composition. In forming the pressure-sensitive adhesive layer, it is necessary to adjust the amount of the entire cross-linking agent added and to fully consider the effects of the cross-linking treatment temperature and the cross-linking treatment time. preferable.

The cross-linking treatment temperature and the cross-linking treatment time can be adjusted depending on the cross-linking agent used. The crosslinking treatment temperature is preferably 170 ° C. or lower.

Further, the cross-linking treatment may be performed at the temperature at the time of the drying step of the pressure-sensitive adhesive layer, or a separate cross-linking treatment step may be provided after the drying step.

The crosslinking treatment time can be set in consideration of productivity and workability, but is usually about 0.2 to 20 minutes, preferably about 0.5 to 10 minutes.

As a method of forming the pressure-sensitive adhesive layer, for example, the pressure-sensitive adhesive composition is applied to a peel-treated separator or the like, and a polymerization solvent or the like is dried and removed to form the pressure-sensitive adhesive layer, and then an anchor is formed in the embodiments of FIGS. It is produced by a method of transferring to a coat layer, or in the embodiments of FIGS. 1 and 2, a method of applying the pressure-sensitive adhesive composition to the anchor coat layer and drying and removing a polymerization solvent or the like to form a pressure-sensitive adhesive layer on a polarizing film. To. When applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

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

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

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

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm. It is 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 by a sheet (separator) that has been peeled off until it is put into practical use.

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

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

The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. If necessary, the separator may be used for mold release and antifouling treatment with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agent, silica powder, etc. It is also possible to perform antistatic treatment such as. In particular, the peelability from the pressure-sensitive adhesive layer can be further enhanced 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 peeled sheet used in producing the above-mentioned polarizing film with an adhesive layer can be used as it is as a separator for the polarizing film with an adhesive layer, and the process can be simplified.

<Surface protection film>
A surface protective film can be provided on the polarizing film with the pressure-sensitive adhesive layer. The surface protective film usually has a base film and an adhesive layer, and protects the polarizer through the adhesive layer.

As the base film of the surface protective film, a film material having isotropic or nearly isotropic is selected from the viewpoint of inspectability and controllability. Examples of the film material include polyester resins such as polyethylene terephthalate films, cellulose resins, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and acrylic resins. Examples include transparent polymers such as resins. Of these, polyester-based resins are preferable. The base film can be used as a laminate of one or more film materials, or a stretched product of the film can also be used. The thickness of the base film is generally 500 μm or less, preferably 10 to 200 μm.

As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer of the surface protective film, a pressure-sensitive adhesive based on a polymer such as (meth) acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer. Can be appropriately selected and used. From the viewpoint of transparency, weather resistance, heat resistance and the like, an acrylic pressure-sensitive adhesive using 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.

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

<Other optical layers>
The polarizing film with an adhesive layer of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited, but is used for forming, for example, a reflector, a transflective plate, a retardation plate (including a wave plate such as 1/2 or 1/4), a liquid crystal display device such as a viewing angle compensation film, or the like. One or two or more optical layers that may be used can be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film in which a reflecting plate or a semi-transmissive reflecting plate is further laminated on a polarizing film with an adhesive layer of the present invention, and elliptically polarized light in which a retardation plate is further laminated on a polarizing film. A film, a circularly polarizing film, a wide viewing angle polarizing film in which a viewing angle compensating film is further laminated on a polarizing film, or a polarizing film in which a brightness improving film is further laminated on a polarizing film is preferable.

The optical film in which the above optical layer is laminated on the polarizing film with an adhesive layer can also be formed by a method of sequentially and separately laminating in the manufacturing process of a liquid crystal display device or the like, but the optical film is formed by laminating in advance. Is excellent in quality stability and assembly work, and has an advantage that the manufacturing process of a liquid crystal display device or the like can be improved. An appropriate adhesive means such as an adhesive layer can be used for laminating. When adhering the above-mentioned polarizing film with an adhesive layer or other optical film, the optical axes thereof can be arranged at an appropriate arrangement angle according to a target phase difference characteristic or the like.

The polarizing film or optical film with an adhesive layer of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, the liquid crystal display device is generally formed by appropriately assembling a liquid crystal cell, a polarizing film or an optical film with an adhesive layer, and if necessary, components such as a lighting system, and incorporating a drive circuit. The present invention is not particularly limited except that the polarizing film with an adhesive layer or the optical film according to the present invention is used, and the same can be applied to the conventional ones. As the liquid crystal cell, any type such as IPS type and VA type can be used.

An appropriate liquid crystal display device such as a liquid crystal display device in which a polarizing film with an adhesive layer or an optical film is arranged on one side or both sides of the liquid crystal cell, or a lighting system using a backlight or a reflector can be formed. In that case, the polarizing film or optical film with an adhesive layer according to the present invention can be installed on one side or both sides of the liquid crystal cell. When polarizing films or optical films with an adhesive layer are provided on both sides, they may be the same or different. Further, when forming the liquid crystal display device, for example, an appropriate component such as a diffuser plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, and a backlight is placed in one layer or at an appropriate position. Two or more layers can be arranged.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples shown below. In addition, each part and% in each example is based on weight. All the conditions for leaving at room temperature, which are not specified below, are 23 ° C. and 65% RH.

<Measurement of weight average molecular weight of (meth) acrylic polymer>
The weight average molecular weight of the (meth) acrylic polymer was measured by GPC (gel permeation chromatography).
-Analyzer: HLC-8120GPC manufactured by Tosoh Corporation
-Column: Made by Tosoh, G7000H _XL + GMH _XL + GMH _XL
-Column size: 7.8 mm φ x 30 cm each, 90 cm in total
-Column temperature: 40 ° C
・ Flow rate: 0.8 ml / min
・ Injection amount: 100 μl
-Eluent: Tetrahydrofuran-Detector: Differential Refractometer (RI)
・ Standard sample: Polystyrene

<Making a polarizer>
Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption rate of 0.75% and a Tg of 75 ° C. Alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6%, degree of saponification 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. , Trade name "Gosefimer Z200") at a ratio of 9: 1 was applied and dried at 25 ° C. to form a PVA-based resin layer having a thickness of 11 μm to prepare a laminate.
The obtained laminate was uniaxially stretched at the free end in the longitudinal direction (longitudinal direction) 2.0 times between rolls having different peripheral speeds in an oven at 120 ° C. (aerial auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 30 ° C. (an aqueous boric acid solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Next, the polarizing plate was immersed in a dyeing bath having a liquid temperature of 30 ° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 parts by weight of iodine was mixed with 100 parts by weight of water, and 1.0 part by weight of potassium iodide was mixed and immersed in the obtained iodine aqueous solution for 60 seconds (dyeing treatment). ..
Next, it was immersed in a cross-linked bath at a liquid temperature of 30 ° C. (an aqueous boric acid solution obtained by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds. (Crossing treatment).
Then, the laminate is immersed in an aqueous solution of boric acid having 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 respect to 100 parts by weight of water). However, uniaxial stretching was performed between rolls having different peripheral speeds so that the total stretching ratio was 5.5 times in the longitudinal direction (longitudinal direction) (underwater stretching 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 100 parts by weight of water) (cleaning treatment).
From the above, an optical film laminate containing a polarizer having a thickness of 5 μm was obtained.

(Making a protective film)
Protective film: A (meth) acrylic resin film having a lactone ring structure having a thickness of 40 μm was used after being subjected to corona treatment on the easily adhesive-treated surface.

(Preparation of adhesive to be applied to protective film)
An ultraviolet curable adhesive was prepared by mixing 40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloyl morpholine (ACMO), and 3 parts by weight of the photoinitiator "IRGACURE 819" (manufactured by BASF).

<Making a single protective polarizing film>
The protective film is attached to the surface of the polarizing film of the optical film laminate while applying the ultraviolet curable adhesive so that the thickness of the adhesive layer after curing is 0.5 μm, and then the active energy is activated. As a line, ultraviolet rays were irradiated to cure the adhesive. For ultraviolet irradiation, gallium-filled metal halide lamp, irradiation device: Fusion UV Systems, Light HAMMER10 manufactured by Inc., valve: V valve, peak illuminance: 1600 mW / cm ² , cumulative irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm). ), And the illuminance of ultraviolet rays was measured using a Solar-Check system manufactured by Solartell. Next, the amorphous PET substrate was peeled off to prepare a single-protective polarizing film A using a thin polarizing film. The optical characteristics of the obtained single-protective polarizing film were a transmittance of 42.8% and a degree of polarization of 99.99%.

<Forming material for anchor coat layer: Polyvinyl alcohol-based resin composition>
100 parts of polyvinyl alcohol resin having a degree of polymerization of 2500 and a degree of saponification of 99.7 mol% and 5 parts of methylol melamine (manufactured by DIC, trade name "Watersol: S-695") are dissolved in pure water to provide a solid content. An aqueous solution having a concentration of 4% by weight was prepared.

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

(Preparation of adhesive composition)
Oligomer-type mercapto group-containing silane coupling agent (alkoxy group amount: 30% by weight, mercapto equivalent: 450 g / mol, X- manufactured by Shin-Etsu Chemical Industry Co., Ltd.) with respect to 100 parts of the solid content of the acrylic polymer solution. 41-1810) 0.2 part and 0.42 part of dibenzoyl peroxide were mixed to prepare an acrylic pressure-sensitive adhesive solution.

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

Example 1
<Making a single protective polarizing film with an anchor coat layer>
The thickness of the polyvinyl alcohol-based resin composition adjusted to 25 ° C. after drying with a wire bar coater on the surface of the polarizing film (polarizer) of the single protective polarizing film (polarizer surface without the protective film) After coating to 1 μm, the film was dried with hot air at 90 ° C. for 20 seconds to prepare a single-protective polarizing film with an anchor coat layer.

<Preparation of polarizing film with adhesive layer>
Next, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet (separator) was bonded to the anchor coat layer formed on the one-side protective polarizing film to prepare a polarizing film with a pressure-sensitive adhesive layer.

Examples 2-11, Comparative Examples 1-6
In Example 1, the type of the water-based resin to be blended in the anchor coat layer, the blending amount of the polymer melamine (the blended portion is a value with respect to 100 parts of the water-based resin), the silane coupling agent in the pressure-sensitive adhesive composition, and the type of the cross-linking agent And the compounding amount (the compounding portion is a value with respect to 100 parts of the acrylic polymer) as shown in Table 1, except that the single protective polarizing film and the pressure-sensitive adhesive with the anchor coat layer were obtained in the same manner as in Example 1. A layered polarizing film was produced.

The following evaluations were performed on the polarizing films with an adhesive layer obtained in the above Examples and Comparative Examples. The results are shown in Table 1.

<Measurement of initial gel fraction>
Sample 1 was prepared by scraping about 0.1 g from the pressure-sensitive adhesive layer formed on the peel-processed surface of the separator film within 1 minute. The sample 1 was wrapped in a Teflon (registered trademark) film having a diameter of 0.2 μm (trade name “NTF1122”, manufactured by Nitto Denko KK) and then tied with a kite string to obtain sample 2. The weight of the sample 2 before being subjected to the following test was measured, and this was designated as the weight A. The weight A is the total weight of the sample 1 (adhesive layer), the Teflon (registered trademark) film, and the kite string. Further, the total weight of the Teflon (registered trademark) film and the kite string was defined as the weight B. Next, the sample 2 was placed in a 50 ml container filled with ethyl acetate and allowed to stand at 23 ° C. for 1 week. Then, the sample 2 was taken out from the container and dried at 130 ° C. for 2 hours in a dryer to remove ethyl acetate, and then the weight of the sample 2 was measured. The weight of the sample 2 after being subjected to the test was measured and used as the weight C. Then, the gel fraction was calculated from the following formula.
Gel fraction (% by weight) = (CB) / (AB) x 100
The initial gel fraction of the pressure-sensitive adhesive layer is preferably 80% or more. A low gel fraction leads to problems such as dents tending to remain.

<Anchoring power>
The polarizing film with an adhesive layer obtained in Examples and Comparative Examples was cut to a size of 25 mm × 150 mm, and indium-tin oxide was vapor-deposited on the adhesive layer surface of the polarizing film and the surface of a polyethylene terephthalate film having a thickness of 50 μm. The film was bonded so as to be in contact with the vapor-deposited surface of the film. After that, the end portion of the polyethylene terephthalate film was peeled off by hand, and after confirming that the adhesive layer was attached to the polyethylene terephthalate film side, 180 ° using a tensile tester AG-1 manufactured by Shimadzu Corporation. The stress (N / 25 mm) at the time of peeling in the direction at a speed of 300 mm / min was measured (25 ° C.).
It is good that the anchoring force is 15 N / 25 mm or more because there is no adhesive residue during rework, no adhesive chipping or adhesive loss during processing. Further, the fracture state at the time of the peeling is indicated by "aggregate fracture (destruction of the anchor coat layer or the pressure-sensitive adhesive layer)" or "interfacial peeling (peeling at the interface between the anchor coat layer and the pressure-sensitive adhesive layer)". In Comparative Example 7, since only the isocyanate-based cross-linking agent was used as the cross-linking agent for the pressure-sensitive adhesive layer, the anchoring force was measured after aging for 48 hours. Examples and other comparative examples are values measured within 24 hours (without aging) after the polarizing film with the pressure-sensitive adhesive layer was prepared.

In Table 1, the peroxides are trade names: NOF BMT 40SV, benzoyl peroxide, manufactured by NOF CORPORATION;
The isocyanate type is trade name: Takenate D110N, trimethylolpropane adduct of xylylene diisocyanate, manufactured by Mitsui Chemicals, Inc.;
X-41-1810: Oligomer-type mercapto group-containing silane coupling agent, alkoxy group amount: 30% by weight, mercapto equivalent: 450 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd .;
KBM-802: Monomer-type mercapto group-containing silane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd .;
KBM-803: Monomer-type mercapto group-containing silane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd .;
X-41-1056: Oligomer type epoxy group-containing silane coupling agent, alkoxy group amount: 17% by weight, epoxy equivalent: 280 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd .;
Is shown.
The cross-linking agent of Example 10 is a combined system of an isocyanate-based cross-linking agent and a peroxide-based cross-linking agent.
Oxazoline group-containing polymer: Epocross WS-700 (manufactured by Nippon Shokubai Co., Ltd.);
Polyurethane resin: Takelac W-6020 (manufactured by Mitsui Chemicals Polyurethane Co., Ltd.);
Epoxy resin: Celoxide 2021P (manufactured by Daicel Corporation);

1 Polarizer 2 Anchor coat layer (mainly polyvinyl alcohol resin)
3 Adhesive layer 4 Separator 5, 5'Protective film 10 Polarizing film with adhesive layer 11 Polarizing film with adhesive layer

Claims (18)

A polarizing film with an adhesive layer having a polarizer, an anchor coat layer, and an adhesive layer in this order.
The anchor coat layer is in direct contact with the adhesive layer ,
The anchor coat layer is formed of an aqueous resin composition containing a compound (a) having at least one primary alcohol capable of reacting with an aqueous resin and a hydroxyl group at the molecular terminal.
A polarizing film with a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing a base polymer having a hydroxyl group and a mercapto group-containing silane coupling agent. The polarizing film with an adhesive layer according to claim 1, wherein the aqueous resin is at least one selected from a polyvinyl alcohol-based resin, a polyurethane-based resin, an epoxy-based resin, and an oxazoline group-containing polymer. The polarizing film with an adhesive layer according to claim 2, wherein the aqueous resin is a polyvinyl alcohol-based resin. The polarizing film with an adhesive layer according to any one of claims 3, wherein the polyvinyl alcohol-based resin has a saponification degree of 96 mol% or more and an average degree of polymerization of 2000 or more. The pressure-sensitive adhesive according to any one of claims 1 to 4, wherein the aqueous resin composition contains 0.2 to 20 parts by weight of the compound (a) with respect to 100 parts by weight of the aqueous resin. Layered polarizing film. The polarizing film with an adhesive layer according to any one of claims 1 to 5 , wherein the anchor coat layer has a thickness of 0.05 μm or more and 6 μm or less. The polarizing film with an adhesive layer according to any one of claims 1 to 6 , wherein the base polymer having a hydroxyl group is a (meth) acrylic polymer having a hydroxyl group. The pressure-sensitive adhesive composition according to claim 1 to 7 , wherein the pressure-sensitive adhesive composition contains 0.01 to 5 parts by weight of the mercapto group-containing silane coupling agent with respect to 100 parts by weight of the base polymer having a hydroxyl group. The polarizing film with an adhesive layer according to any one. The polarizing film with a pressure-sensitive adhesive layer according to any one of claims 1 to 8 , wherein the pressure-sensitive adhesive composition contains a cross-linking agent. The polarizing film with an adhesive layer according to claim 9 , wherein the cross-linking agent contains a cross-linking agent (b) that does not react with a hydroxyl group. The polarizing film with an adhesive layer according to claim 10, wherein the cross-linking agent (b) that does not react with the hydroxyl group is a peroxide. The pressure-sensitive adhesive according to claim 10 or 11 , wherein the cross-linking agent (b) that does not react with the hydroxyl group is contained in an amount of 0.01 to 2 parts by weight based on 100 parts by weight of the base polymer having the hydroxyl group. Layered polarizing film. The polarizing film with an adhesive layer according to any one of claims 1 to 12 , wherein the polarizing element has a thickness of 15 μm or less. The polarizer has optical characteristics represented by a simple substance transmittance T and a degree of polarization P according to the following formula.
P>-(10 ^0.929 T ^-42.4 -1) x 100 (however, T <42.3), and
The polarizing film with an adhesive layer according to any one of claims 1 to 13 , wherein the polarizing film is configured to satisfy the condition of P ≧ 99.9 (where T ≧ 42.3). The polarizing film with an adhesive layer according to any one of claims 1 to 14 , wherein a protective film is provided on at least one side of the polarizing element. The polarizing film with an adhesive layer according to any one of claims 1 to 15 , wherein a separator is laminated on the adhesive layer. The method for producing a polarizing film with an adhesive layer according to any one of claims 1 to 16 .
A water-based resin composition containing a compound (a) having at least one water-based resin and a primary alcohol capable of reacting with a hydroxyl group at the molecular end is applied onto the polarizer, and then dried and anchored. The process of forming the coat layer and
A step of forming a pressure-sensitive adhesive layer from a pressure-sensitive adhesive composition containing a base polymer having a hydroxyl group and a mercapto group-containing silane coupling agent on the anchor coat layer.
A method for producing a polarizing film with an adhesive layer, which comprises. An image display device having the polarizing film with an adhesive layer according to any one of claims 1 to 16 .

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