JP7372275B2 - Polarizing film with adhesive layer, optical member, and image display device - Google Patents

Description

The present invention relates to a polarizing film with an adhesive layer and an optical member including the polarizing film with an adhesive layer. The present invention also relates to an image display device including the polarizing film with an adhesive layer and/or the optical member.

In recent years, there has been a strong demand for lighter weight and thinner image display devices such as liquid crystal display devices, and various optical components such as polarizing films used in image display devices are also required to be thinner and lighter. Due to the demand, various methods of manufacturing thin polarizing films are being studied.

A method for manufacturing a thin polarizing film is, for example, by uniaxially stretching a thin polyvinyl alcohol (PVA) polymer layer formed on a resin base material having a certain thickness while being integrated with the resin base material. There is a method of forming a polarizing film on a resin base material (for example, see Patent Document 1), and a method of forming a laminated film in which a resin layer made of PVA resin is formed on one side of a base film at a specific stretching ratio. A method is known in which a stretched film is obtained by longitudinal uniaxial stretching, and the stretched film is dyed with a dichroic dye to form a thin polarizer (for example, see Patent Document 2).

Patent No. 4691205 specification Patent No. 5048120 specification

The thinned polarizing films obtained in Patent Documents 1 and 2 are both single-sided polarizing films in which one side of a polarizer is protected with a transparent protective film, and an adhesive is applied to the polarizer side of the single-sided protective polarizing film. It can be attached to various optical members through layers and incorporated into an image display device.

Although the single-sided protective polarizing film is excellent from the viewpoint of thinning, when the single-sided protective polarizing film is bonded to an adherend and exposed to a high temperature and humid environment, moisture transfers to the polarizer. There was a problem in that the polarizer deteriorated (depolarization occurred).

Therefore, an object of the present invention is to provide a polarizing film with an adhesive layer that can suppress deterioration of the polarizer of a single-protected polarizing film in a high-temperature and humid environment. Another object of the present invention is to provide a polarizing film with an adhesive layer, wherein the adhesive layer of the polarizing film with an adhesive layer is a light-diffusing adhesive layer. Another object of the present invention is to provide an optical member including the polarizing film with an adhesive layer, and an image display device including the polarizing film with an adhesive layer and/or the optical member.

As a result of intensive studies to solve the above problems, the present inventors discovered the following polarizing film with an adhesive layer and completed the present invention.

That is, the present invention is a polarizing film with an adhesive layer having a polarizing film and an adhesive layer A provided on the polarizing film,
The polarizing film is a single-sided protective polarizing film having a transparent protective film only on one side of a polarizer having a thickness of 10 μm or less, and the adhesive layer A is on the side of the polarizer that does not have the transparent protective film. It is provided,
The adhesive layer A relates to a polarizing film with an adhesive layer, characterized in that the adhesive layer A has a moisture permeability of 300 g/(m ² ·24 h) or less and a thickness of 50 μm or less.

It is preferable that the adhesive layer A is an adhesive layer containing a rubber-based polymer as a main component.

It is preferable that the rubber-based polymer is one or more rubber-based polymers selected from the group consisting of styrene-based thermoplastic elastomer, polyisobutylene, and butyl rubber.

It is preferable that the adhesive layer A further contains a tackifying resin.

The adhesive layer A may be a light-diffusing adhesive layer A1 containing light-diffusing fine particles.

It is preferable that the light-diffusing adhesive layer A1 has a haze of 10 to 95%.

It is preferable that the light-diffusing fine particles are silicone resin fine particles or styrene resin fine particles.

The volume average particle diameter of the light-diffusing fine particles is preferably 1 to 4 μm.

The present invention also relates to an optical member comprising the polarizing film with an adhesive layer and a brightness enhancement film provided on the adhesive layer A or adhesive layer A1 side of the polarizing film with an adhesive layer. .

In the optical member, a prism sheet can be further provided on the side of the brightness-enhancing film that does not have the adhesive layer-attached polarizing film.

Furthermore, the present invention relates to an image display device comprising one or more selected from the group consisting of the polarizing film with an adhesive layer and the optical member.

Since the polarizing film with an adhesive layer of the present invention uses a single-protection polarizing film, it can be made thinner, and the moisture permeability of the adhesive layer A is 300 g/(m ² · 24 h) or less. Moreover, since the thickness is 50 μm or less, deterioration of the polarizer in a high temperature and humid environment can be suppressed. That is, in the polarizing film with an adhesive layer of the present invention, the adhesive layer A has a low moisture permeability and a thickness of 50 μm or less, so even when exposed to a high temperature humid environment, moisture does not flow into the polarizer. As a result, depolarization due to deterioration of the polarizer can be suppressed. In addition, when the adhesive layer A is a light-diffusing adhesive layer A1, the polarizing film with an adhesive layer of the present invention has a light-diffusing function, so it can be used instead of a diffusion sheet used in an image display device. This allows the image display device to be made thinner. Further, by using the polarizing film with an adhesive layer having the light diffusion function on the backlight side, it is possible to eliminate the bias of light from the backlight, and a more uniform display can be achieved. Further, the optical member and image display device of the present invention have high reliability because they contain the adhesive layer-attached polarizing film of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically one Embodiment of the polarizing film with an adhesive layer of this invention. 1 is a cross-sectional view schematically showing an embodiment of an optical member of the present invention. 1 is a cross-sectional view schematically showing an embodiment of an optical member of the present invention.

1. Polarizing film with adhesive layer The polarizing film with adhesive layer of the present invention has a polarizing film and an adhesive layer A provided on the polarizing film,
The polarizing film is a single-sided protective polarizing film having a transparent protective film only on one side of a polarizer having a thickness of 10 μm or less, and the adhesive layer A is on the side of the polarizer that does not have the transparent protective film. It is provided,
The adhesive layer A is characterized in that its moisture permeability is 300 g/(m ² ·24 h) or less, and its thickness is 50 μm or less.

The structure of the adhesive layer-attached polarizing film of the present invention will be explained in detail with reference to the drawings. In addition, the dimensions of each structure in FIG. 1 show an example, and the present invention is not limited thereto.

As shown in FIG. 1, a polarizing film with an adhesive layer 1 of the present invention has an adhesive layer A (3 in FIG. 1) on at least one side of a polarizing film 2. Further, the polarizing film 2 has a transparent protective film 5 only on one side of the polarizer 4, and the adhesive layer A(3) is on the side of the polarizer 4 that does not have the transparent protective film 5. (In other words, it is sufficient if it is provided on the polarizer 4 side). Although the polarizer 4 and the adhesive layer A(3) do not necessarily need to be in contact with each other, it is preferable that they are in contact with each other from the viewpoint of significantly exerting the effects of the present invention.

Moreover, an adhesive layer B (not shown) can be further provided on the side of the transparent protective film 5 that does not have the polarizer 4. The adhesive layer B provided on the transparent protective film 5 may be the adhesive layer A having the above-mentioned specific moisture permeability, or may be any other adhesive layer. The adhesive layer B will be described later.

(1) Adhesive layer A
The adhesive layer A used in the present invention is characterized by having a moisture permeability of 300 g/(m ² ·24 h) or less and a thickness of 50 μm or less.

The adhesive layer A used in the present invention has a moisture permeability of 300 g/(m ² · 24 h) or less and has a low water vapor transmittance, so it can suppress deterioration of the polarizer due to moisture etc. It is. The moisture permeability is measured at 40°C and 92%R. H. The water vapor permeability (moisture permeability) under these conditions can be measured by the method described in Examples.

The moisture permeability is 300 g/(m ²・24 h) or less, preferably 200 g/(m ²・24 h) or less, more preferably 100 g/(m ²・24 h) or less, and 60 g/(m 2 ・24 h) or less. ( ^m2 ·24h) or less is particularly preferable. Further, the lower limit of moisture permeability is not particularly limited, but ideally, it is preferable that no water vapor permeates at all (ie, 0 g/(m ² · 24 h)). If the moisture permeability of the adhesive layer A is within the above range, it is possible to suppress the migration of moisture to the polarizer, suppress depolarization due to deterioration of the polarizer, and provide an adhesive with high optical reliability. It can be a layered polarizing film.

The thickness of the adhesive layer A used in the present invention is 50 μm or less, preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. Further, the lower limit of the thickness of the adhesive layer A is not particularly limited, but from the viewpoint of durability, it is preferably 1 μm or more, and more preferably 5 μm or more. As mentioned above, the adhesive layer A used in the present invention has a low water vapor transmittance and a thickness of 50 μm or less, so that it can suppress moisture from migrating to the polarizer in a high temperature humid environment. . As a result, depolarization due to deterioration of the polarizer can be suppressed, and a polarizing film with an adhesive layer having high optical reliability can be obtained.

Moisture transfer to the polarizer of the single-sided protective film occurs from the adhesive surface of the adhesive layer A provided on the single-sided protective polarizing film (i.e., the side of the adhesive layer A opposite to the side on which the polarizer is provided). Moisture transfer from the side surface of the adhesive layer A and moisture transfer from the side surface of the adhesive layer A are considered. Usually, an adherend such as a display panel or a glass plate is bonded to the side of the adhesive layer A opposite to the side with the polarizer, and moisture migration from the surface direction of the adhesive layer A is suppressed to some extent. However, it has been difficult to suppress moisture migration from the side portions of the adhesive layer A. The adhesive layer A used in the present invention has low moisture permeability, has a thickness of 50 μm or less, and has a small area of the side surface of the adhesive layer A, so it is possible to suppress the amount of moisture transferred from the side surface. This makes it possible to suppress depolarization due to deterioration of the polarizer.

The adhesive layer A used in the present invention may be one having moisture permeability and thickness within the above range, and its composition is not limited. For example, a rubber adhesive composition, an acrylic adhesive composition, a silicone adhesive composition, etc. A material formed from a pressure-sensitive adhesive composition, a urethane pressure-sensitive adhesive composition, or the like can be used as appropriate. Among these, from the viewpoint of moisture permeability, a rubber-based adhesive composition having a rubber-based polymer as a base polymer is preferred. The adhesive layer A used in the present invention preferably contains the above-mentioned rubber-based polymer as a main component. Here, the term "main component" refers to 40% by weight or more of a rubber-based polymer in the adhesive layer A (or in the total solid content of the adhesive composition forming the adhesive layer A).

The rubber-based polymer is a polymer that exhibits rubber elasticity in a temperature range around room temperature. As the rubber-based polymer, it is preferable to use one or more selected from the group consisting of natural rubber, synthetic rubber, and thermoplastic elastomer.

The synthetic rubbers include polyisobutylene (PIB), butadiene rubber (BR), butyl rubber (IIR), isoprene rubber (IR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). , butadiene-isoprene-styrene random copolymer, isoprene-styrene random copolymer, EPR (binary ethylene-propylene rubber), EPT (ternary ethylene-propylene rubber), acrylic rubber, urethane rubber, etc. I can do it. Among these, from the viewpoint of transparency and light resistance, polyisobutylene (PIB) and butyl rubber (IIR) are preferred, and polyisobutylene (PIB) is more preferred.

Examples of the thermoplastic elastomer include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), Styrene-ethylene-propylene-styrene block copolymer (SEPS, hydrogenated product of SIS), styrene-ethylene-propylene block copolymer (SEP, hydrogenated product of styrene-isoprene block copolymer), styrene-isobutylene- Styrenic thermoplastic elastomer (styrene block copolymer) such as styrene block copolymer (SIBS); polyurethane thermoplastic elastomer; polyester thermoplastic elastomer; polymer blend of polypropylene and EPT (ternary ethylene-propylene rubber) Examples include blended thermoplastic elastomers such as. Among these, from the viewpoint of transparency and light resistance, styrene thermoplastic elastomers are preferred, and styrene-ethylene-propylene-styrene block copolymers (SEPS, hydrogenated products of SIS) are more preferred.

The adhesive composition contains a rubber-based polymer as a base polymer, and the content of the rubber-based polymer in the adhesive composition is preferably 40% by weight or more, and preferably 50% by weight or more. The content is more preferably 60% by weight or more. The upper limit of the content of the rubber-based polymer is not particularly limited, and may be up to 100% by weight, preferably up to 95% by weight.

The pressure-sensitive adhesive composition preferably further contains a tackifier resin from the viewpoint of adhesiveness to adherends such as polarizers, optical films, glass, and display panels.

Examples of the tackifying resin include terpene-based tackifying resins, phenol-based tackifying resins, rosin-based tackifying resins, petroleum resin-based tackifying resins, etc., and these may be used alone or in combination of two or more. Can be used in combination. Among these, terpene-based tackifying resins are preferred from the viewpoint of transparency and adhesiveness.

Terpene-based tackifying resins include, for example, terpene polymers such as α-pinene polymer, β-pinene polymer, and dipentene polymer, and modified terpene polymers (phenol modification, styrene modification, aromatic modification, hydrogen Examples include modified terpene resins that have been modified (additive modification, hydrocarbon modification, etc.). Examples of the modified terpene resin include terpene phenol resin, styrene-modified terpene resin, aromatic-modified terpene resin, hydrogenated terpene resin (hydrogenated terpene resin), and the like. Examples of the hydrogenated terpene resin herein include hydrides of terpene polymers, other modified terpene resins, and hydrides of terpene phenol resins.

As the tackifying resin, commercial products such as the Clearon series and Polyster series manufactured by Yasuhara Chemical Co., Ltd., the Super Ester series, Pencell series, and Pine Crystal series manufactured by Arakawa Chemical Co., Ltd. can be used, for example. .

The softening point (softening temperature) of the tackifying resin is not particularly limited, but, for example, it is preferably about 80°C or higher, more preferably about 100°C or higher. The upper limit of the softening point of the tackifier resin is not particularly limited, but is preferably about 200°C or lower, and preferably about 180°C or lower, for example. The softening point of the tackifier resin herein is defined as a value measured by a softening point test method (ring and ball method) specified in either JIS K5902 or JIS K2207.

The amount of the tackifying resin added is preferably 100 parts by weight or less, more preferably 80 parts by weight or less, and even more preferably 50 parts by weight or less, based on 100 parts by weight of the base polymer. . The lower limit of the amount of the tackifying resin added is not particularly limited, but is preferably 0 parts by weight or more, more preferably 1 part by weight or more, and preferably 5 parts by weight or more. More preferred. It is preferable to use the amount of the tackifier resin within the above range in order to ensure heat resistance and adhesiveness.

Moreover, an organic solvent can be added to the pressure-sensitive adhesive composition as a diluent. Examples of the diluent include, but are not limited to, hexane, heptane, toluene, xylene, dimethyl ether, etc., and these may be used alone or in combination of two or more. can. Among these, toluene is preferred.

The amount of the diluent added is not particularly limited, but it is preferably about 50 to 500 parts by weight, and about 100 to 300 parts by weight, based on 100 parts by weight of the base polymer in the adhesive composition. It is more preferable that there be. It is preferable that the amount of the diluent added be within the above range from the viewpoint of coatability on a support and the like.

The adhesive composition may further contain any suitable additive. Specific examples of additives include crosslinking agents (eg, polyisocyanates, epoxy compounds, alkyl etherified melamine compounds, etc.), plasticizers, fillers, anti-aging agents, and the like. The type, combination, amount, etc. of additives added to the adhesive composition can be appropriately set depending on the purpose. The content (total amount) of the additives in the adhesive composition is preferably 50% by weight or less, more preferably 40% by weight or less, and even more preferably 30% by weight or less.

(Light diffusion adhesive layer A1)
The adhesive layer A may be a light-diffusing adhesive layer A1 containing light-diffusing fine particles. When the adhesive layer A is a light-diffusing adhesive layer A1, it is preferable because a light-diffusing function can be imparted to the polarizing film with an adhesive layer of the present invention.

Any suitable light-diffusing particles can be used as the light-diffusing fine particles. Specific examples include inorganic fine particles, polymer fine particles, etc. Among these, polymer fine particles are preferred.

Examples of the material of the polymer fine particles include silicone resin, styrene resin, methacrylic resin (eg, polymethyl methacrylate), polystyrene resin, polyurethane resin, and melamine resin. These resins have excellent dispersibility in the pressure-sensitive adhesive composition and an appropriate difference in refractive index from the pressure-sensitive adhesive composition, so that a light-diffusing pressure-sensitive adhesive layer A1 having excellent light-diffusing performance can be obtained. Among these, silicone resins and styrene resins are particularly preferred.

The shape of the light-diffusing fine particles may be, for example, true spherical, flat, or irregular. The light-diffusing fine particles may be used alone or in combination of two or more types.

The refractive index of the light-diffusing fine particles used in the present invention is preferably lower than the refractive index of the pressure-sensitive adhesive composition. The above-mentioned "refractive index of the adhesive composition" refers to the refractive index of the adhesive composition that does not contain the light-diffusing fine particles (that is, the adhesive composition before adding the light-diffusing fine particles). The refractive index of the light-diffusing fine particles is preferably 1.30 to 1.70, more preferably 1.40 to 1.65. If the refractive index of the light-diffusing fine particles is within the above range, the difference in refractive index with the adhesive composition can be set within the desired range, and as a result, a light-diffusing adhesive layer A1 having a desired haze value can be obtained. This is preferable because it can be done.

The absolute value of the refractive index difference between the light-diffusing fine particles and the adhesive composition is preferably greater than 0 and 0.2 or less, more preferably greater than 0 and 0.15 or less, and 0. It is more preferably from 01 to 0.13.

The volume average particle diameter of the light-diffusing fine particles is preferably about 1 to 4 μm, more preferably about 2 to 4 μm. It is preferable that the volume average particle diameter of the light-diffusing fine particles is within the above range, since a light-diffusing adhesive layer A1 having a desired haze value can be obtained by combining with the pressure-sensitive adhesive composition. Note that the volume average particle diameter can be measured using, for example, an ultracentrifugal automatic particle size distribution measuring device.

The content of light diffusing fine particles in the light diffusing adhesive layer A1 is not particularly limited, but is preferably 0.3 to 50% by weight, more preferably 3 to 48% by weight. , more preferably 3 to 30% by weight. By setting the blending amount of the light-diffusing fine particles within the above range, a light-diffusing adhesive layer A1 having excellent light-diffusing performance can be obtained.

The haze of the light-diffusing adhesive layer A1 is not particularly limited, but is preferably 10 to 95%, more preferably 20 to 85%, and even more preferably 30 to 70%. preferable. Setting the haze value within the above range is preferable because desired diffusion performance can be obtained and the occurrence of moire and glare can be suppressed well. The light diffusing performance of the light diffusing adhesive layer A1 can be controlled by adjusting the constituent materials of the matrix (adhesive), the constituent materials of the light diffusing fine particles, the volume average particle diameter, the blending amount, etc.

The method for forming the adhesive layer A (or A1) will be described later.

(2) Polarizing film The polarizing film used in the present invention is a single-sided protective polarizing film having a transparent protective film on only one side of the polarizer.

In the present invention, a thin polarizer having a thickness of 10 μm or less is used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. Such a thin polarizer is preferable because it has less unevenness in thickness, has excellent visibility, has less dimensional change, has excellent durability, and can also be made thinner as a polarizing film.

Typical examples of thin polarizers include JP-A-51-069644, JP-A 2000-338329, WO 2010/100917 pamphlet, JP-A 2014-59328, and JP-A 2014-59328. The thin polarizing film described in 2012-73563 can be mentioned. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol resin (hereinafter also referred to as PVA resin) layer and a resin base material for stretching in the state of a laminate, 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.

The thin polarizing film is manufactured using International Publication No. 2010/100917 pamphlet because it can be stretched to a high magnification and improves polarization performance among manufacturing methods that include a process of stretching a laminate and a dyeing process. , or those obtained by a manufacturing method including a step of stretching in a boric acid aqueous solution as described in JP-A No. 2014-059328 and JP-A-2012-073563 are preferable, and in particular, those obtained by a manufacturing method including a step of stretching in a boric acid aqueous solution as described in JP-A No. 2014-059328 and JP-A No. 2012-073563 are preferable. It is preferable to use a manufacturing method described in JP-A-2012-073563 that includes a step of supplementary stretching in air before stretching in a boric acid aqueous solution.

The material for forming the transparent protective film provided on one side of the polarizer is preferably one that has excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and the like. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples include polycarbonate-based polymers and polycarbonate-based polymers. In addition, polyolefin polymers such as polyethylene, polypropylene, cyclo- or norbornene-structured polyolefins, 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, arylate polymer, polyoxymethylene polymer, epoxy polymer, or Blends of the above-mentioned polymers are also mentioned as examples of the polymers forming the above-mentioned transparent protective film. The transparent protective film can also be formed as a cured layer of thermosetting or ultraviolet curing resin such as acrylic, urethane, acrylic urethane, epoxy, or silicone resin.

The thickness of the protective film can be determined as appropriate, but is generally about 1 to 500 μm from the viewpoint of strength, workability such as handling, thin film properties, etc.

The polarizer and the protective film are usually in close contact with each other via a water-based adhesive or the like. Examples of water-based adhesives include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latex adhesives, water-based polyurethanes, and water-based polyesters. In addition to the above, examples of the adhesive between the polarizer and the transparent protective film include ultraviolet curable adhesives and electron beam curable adhesives. The electron beam curable adhesive for polarizing film exhibits suitable adhesiveness to the various transparent protective films described above. Further, the adhesive used in the present invention can contain a metal compound filler.

The surface of the transparent protective film to which the polarizer is not attached may be treated with a hard coat layer, antireflection treatment, antisticking treatment, or diffusion or antiglare treatment.

(3) Polarizing film with adhesive layer The polarizing film with adhesive layer of the present invention can be obtained by applying the adhesive composition directly to the polarizer of the single-sided protective polarizing film and removing the solvent etc. by heating and drying. , an adhesive layer A (or A1) can be formed on a polarizer. Moreover, the adhesive layer A (or A1) formed on the support etc. can also be transferred onto the polarizer of the said single-sided protective polarizing film, and the polarizing film with an adhesive layer can also be formed.

Various methods can be used to apply the adhesive composition. 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 methods such as extrusion coating.

The heat drying temperature is preferably about 30°C to 200°C, more preferably 40°C to 180°C, even more preferably 80°C to 150°C. By setting the heating temperature within the above range, an adhesive layer A (or A1) having excellent adhesive properties can be obtained. As the drying time, an appropriate time can be adopted as needed. The drying time is preferably about 5 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 1 minute to 8 minutes.

As the support, for example, a release-treated sheet (separator) can be used. As the release-treated sheet, a silicone release liner is preferably used.

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

Examples of the plastic film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, and ethylene. -Vinyl acetate copolymer film, etc.

The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. The separator may be treated with silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agents, mold release with silica powder, etc., antifouling treatment, coating type, kneading type, vapor deposition, etc., as necessary. It is also possible to perform antistatic treatment on molds, etc. In particular, by appropriately performing a peeling treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the separator, the peelability from the adhesive layer A (or A1) can be further improved.

Note that the release-treated sheet used in producing the above-described polarizing film with an adhesive layer can be used as it is as a separator of the polarizing film with an adhesive layer, thereby simplifying the process.

In the polarizing film with an adhesive layer, when forming the adhesive layer A (or A1), an anchor layer is formed on the surface of the polarizer, and various adhesion-facilitating treatments such as corona treatment and plasma treatment are performed on the surface of the polarizer. After that, an adhesive layer can be formed. Further, the surface of the pressure-sensitive adhesive layer A (or A1) may be subjected to an adhesion-facilitating treatment.

Since the polarizing film with an adhesive layer of the present invention uses a single-protection polarizing film in which the thickness of the polarizer is 10 μm or less, the entire polarizing film with an adhesive layer can be made thin. The thickness of the polarizing film with an adhesive layer can be 35 μm or less.

(4) Other layers The polarizing film with an adhesive layer of the present invention may include, for example, an adhesive layer B other than the adhesive layer A, in addition to the polarizing film and the adhesive layer A (or A1). can. Specifically, for example, another adhesive layer B can be formed on the transparent protective film side of the polarizing film with an adhesive layer. The adhesive layer B is not particularly limited, and may be the adhesive layer A or the light-diffusing adhesive layer A1, or may be formed from an adhesive composition containing various other base polymers. A pressure-sensitive adhesive layer can be used as appropriate.

The type of base polymer is not particularly limited, and examples include various polymers such as (meth)acrylic polymers, silicone polymers, and urethane polymers. Among these base polymers, (meth)acrylic polymers are preferably used because they have excellent optical transparency, exhibit suitable adhesive properties such as wettability, cohesiveness, and adhesion, and are excellent in weather resistance and heat resistance. be done. Hereinafter, an acrylic pressure-sensitive adhesive whose base polymer is a (meth)acrylic polymer containing an alkyl (meth)acrylate as a monomer unit, which is a forming material of the pressure-sensitive adhesive layer B, will be explained.

The (meth)acrylic polymer can be obtained by polymerizing a monomer component containing an alkyl (meth)acrylate having an alkyl group having 4 to 24 carbon atoms at the end of an ester group. Note that alkyl (meth)acrylate refers to alkyl acrylate and/or alkyl methacrylate, and (meth) in the present invention has the same meaning.

Examples of alkyl (meth)acrylates include those having a linear or branched alkyl group having 4 to 24 carbon atoms. Alkyl (meth)acrylates can be used alone or in combination of two or more.

It is preferable that the (meth)acrylic polymer for the adhesive layer B contains the largest amount of butyl acrylate as a monomer unit in order to control the storage modulus and to improve processability, storage properties, and durability.

In the present invention, the alkyl (meth)acrylate having an alkyl group having 4 to 24 carbon atoms at the ester end is 40% by weight or more based on the total amount of monofunctional monomer components forming the (meth)acrylic polymer. The content is preferably 50% by weight or more, still more preferably 60% by weight or more.

The monomer component forming the (meth)acrylic polymer may contain a copolymerizable monomer other than the alkyl (meth)acrylate as a monofunctional monomer component. Examples of such copolymerizable monomers include cyclic nitrogen-containing monomers, hydroxyl group-containing monomers, carboxyl group-containing monomers, and monomers having cyclic ether groups.

In the present invention, the copolymerizable monomer can be used as the remainder of the alkyl (meth)acrylate in the monomer component, and is 60% by weight or less based on the total amount of the monofunctional monomer component forming the (meth)acrylic polymer. The content is preferably 50% by weight or less, and even more preferably 40% by weight or less.

In addition to the above, various copolymer monomers having polymerizable functional groups having unsaturated double bonds such as (meth)acryloyl groups or vinyl groups, silane monomers containing silicon atoms, etc. can also be used. .

In addition to the monofunctional monomers listed above, the monomer components forming the (meth)acrylic polymer used in the present invention may include polyfunctional monomers as necessary to adjust the cohesive force of the adhesive. It can contain monomers.

The amount of the polyfunctional monomer used varies depending on its molecular weight, number of functional groups, etc., but it is preferably used in an amount of 3 parts by weight or less, more preferably 2 parts by weight or less, based on a total of 100 parts by weight of the monofunctional monomer. More preferably, it is 1 part by weight or less. The lower limit is not particularly limited, but is preferably 0 parts by weight or more, more preferably 0.001 parts by weight or more. When the amount of the polyfunctional monomer used is within the above range, adhesive strength can be improved.

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

The polymerization initiator, chain transfer agent, emulsifier, etc. used in radical polymerization are not particularly limited, and known ones can be appropriately selected and used. The weight average molecular weight of the (meth)acrylic polymer can be controlled by the amounts of the polymerization initiator and chain transfer agent used and the reaction conditions, and the amounts used are adjusted as appropriate depending on the types of these.

Furthermore, when the (meth)acrylic polymer is produced by active energy ray polymerization, it can be produced by polymerizing the monomer components by irradiating them with active energy rays such as electron beams and ultraviolet rays. When the active energy ray polymerization is performed using an electron beam, it is not particularly necessary to include a photopolymerization initiator in the monomer component, but when the active energy ray polymerization is performed using ultraviolet light polymerization, in particular, A photopolymerization initiator can be included in the monomer component due to the advantage that the polymerization time can be shortened. One type of photopolymerization initiator can be used alone or two or more types can be used in combination. The monomer component may be partially polymerized into syrup before radiation irradiation.

The photopolymerization initiator is not particularly limited, and known ones can be appropriately selected and used. It can be used in the amount usually used.

The adhesive composition forming the adhesive layer B may contain a crosslinking agent. Examples of crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, silicone crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, silane crosslinking agents, alkyl etherified melamine crosslinking agents, metal chelate crosslinking agents, Contains crosslinking agents such as oxides. The crosslinking agents can be used alone or in combination of two or more. As the crosslinking agent, isocyanate crosslinking agents and epoxy crosslinking agents are preferably used.

The above crosslinking agent may be used alone or in combination of two or more, but the total content is based on 100 parts by weight of the (meth)acrylic polymer. It is preferable to contain the crosslinking agent in an amount of 0.01 to 5 parts by weight. The content of the crosslinking agent is preferably 0.01 to 4 parts by weight, more preferably 0.02 to 3 parts by weight.

Further, as a crosslinking agent, an organic crosslinking agent or a polyfunctional metal chelate may be used in combination.

The adhesive composition forming the adhesive layer B may contain a (meth)acrylic oligomer in order to improve adhesive strength.

Furthermore, the adhesive composition forming the adhesive layer B may contain a silane coupling agent. The blending amount of the silane coupling agent is preferably 1 part by weight or less per 100 parts by weight of the (meth)acrylic polymer, more preferably 0.01 to 1 part by weight, even more preferably 0.02 to 0. .6 parts by weight.

Silane coupling agents that can be preferably used include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4epoxycyclohexyl). ) Epoxy group-containing silane coupling agents such as ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1 , 3-dimethylbutylidene) propylamine, amino group-containing silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. Examples include (meth)acrylic group-containing silane coupling agents, isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane, and the like.

Furthermore, the adhesive composition forming the adhesive layer B may contain other known additives, such as polyether compounds of polyalkylene glycol such as polypropylene glycol, colorants, pigments, etc. Powder, dye, surfactant, plasticizer, tackifier, surface lubricant, leveling agent, softener, antioxidant, antiaging agent, light stabilizer, ultraviolet absorber, polymerization inhibitor, inorganic or organic Fillers, metal powders, particles, foils, etc. can be added as appropriate depending on the intended use. Further, within a controllable range, a redox system may be employed in which a reducing agent is added.

The adhesive layer B can be formed, for example, by applying the adhesive composition onto a transparent protective film of a polarizing film and drying and removing the polymerization solvent and the like. When applying the forming material, one or more solvents other than the polymerization solvent may be added as appropriate.

Various methods can be used to apply the pressure-sensitive adhesive composition. 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 methods such as extrusion coating.

The heat drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, particularly preferably 60°C to 170°C. By setting the heating temperature within the above range, a pressure-sensitive adhesive layer B having excellent adhesive properties can be obtained. As the drying time, an appropriate time can be adopted as needed. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, particularly preferably 10 seconds to 5 minutes.

Further, when the forming material (adhesive) is an active energy ray-curable adhesive, the adhesive layer B can be formed by polymerizing by irradiating active energy rays such as ultraviolet rays. A high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, etc. can be used for ultraviolet irradiation.

Further, the adhesive layer B can be formed on a support and then transferred onto a transparent protective film of a polarizing film. As the support, those described in this specification can be used as appropriate.

The adhesive layer B formed on the transparent protective film of the polarizing film may be protected with a sheet (separator) whose adhesive surface has been subjected to a release process until it is put into practical use. In practical use, the peel-treated sheet is peeled off. As the separator, those described herein can be used as appropriate.

The thickness of the adhesive layer B is not particularly limited, but is preferably 30 μm or less, more preferably 1 to 25 μm, even more preferably 5 to 25 μm, and even more preferably 10 to 20 μm. It is particularly preferable that there be.

2. Optical Member The optical member of the present invention is characterized by having the above-mentioned polarizing film with an adhesive layer and a brightness enhancement film provided on the adhesive layer A side of the polarizing film with an adhesive layer.

As shown in FIG. 2, in the optical member 10 of the present invention, the brightness enhancement film 6 may be directly bonded to the adhesive layer-attached polarizing film 1 via the adhesive layer A(3), or other They may be laminated with layers interposed therebetween. Further, as shown in FIG. 3, the optical member 10 of the present invention has a prism attached to the side of the brightness enhancement film 6 that does not have the adhesive layer-attached polarizing film 1 via an adhesive layer (not shown) or the like. Sheets 7 can be further stacked. Prism sheet 7 typically includes a substrate and a prism section.

As the brightness enhancement film 6, a reflective polarizing plate can be used. The reflective polarizing plate is a linearly polarized light separating type polarizing plate. Typical examples include grid-type polarizing plates, multilayer thin film laminated polarizing plates made of two or more materials with different refractive indexes, vapor-deposited multilayer thin films with different refractive indices, and birefringent multilayer thin films made of two or more materials with different refractive indexes. A laminate, a stretched two or more resin laminate using two or more resins with different refractive indexes, a polarizing plate that separates linearly polarized light by reflecting/transmitting it in orthogonal axial directions (linear polarized light separation) type reflective polarizing plate). Among these, a linearly polarized light separating type reflective polarizing plate is preferably used. As such a reflective polarizing plate, for example, those commercially available under the trade name "D-BEF" manufactured by 3M Co., Ltd. or "Nipox APCF" manufactured by Nitto Denko Corporation can also be used.

3. Image Display Device The image display device of the present invention is characterized in that it includes one or more selected from the group consisting of the polarizing film with an adhesive layer and the optical member.

When the adhesive layer A is a diffusion adhesive layer A1, since the polarizing film with an adhesive layer of the present invention has a light diffusion function, it can be used, for example, in place of a diffusion sheet provided on the backlight side of an image display device. be able to. Moreover, in that case, as described above, an optical member can be formed and used together with a brightness enhancement film or a prism sheet.

In addition, when the adhesive layer A of the polarizing film with an adhesive layer of the present invention does not have a diffusion function (that is, when the adhesive layer A does not contain light-diffusing fine particles), the back of the image display device It can be used as a polarizing film for either the light side or the viewing side.

The image display device of the present invention may include the polarizing film with an adhesive layer or the optical member of the present invention, and other configurations may be the same as those of conventional image display devices.

The image display device of the present invention has high reliability because it includes the polarizing film with an adhesive layer or the optical member. Further, since the optical member of the present invention has a light diffusion function, the optical member can be used in place of a diffusion sheet provided on the backlight side, and as a result, the image display device can be made thinner, and , it is possible to eliminate the polarization of light from the backlight, allowing for more uniform display.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. Note that all parts and percentages in each example are based on weight.

Production Example 1 (Production of adhesive composition (A-1))
100 parts by weight of styrene-ethylene-propylene-styrene block copolymer (SEPS, trade name: Septon 2063, styrene content: 13%, manufactured by Kuraray Co., Ltd.) as a pace polymer, and a terpene polymer as a tackifying resin. A pressure-sensitive adhesive composition (A-1) was prepared by mixing 10 parts by weight of a hydride (trade name: Clearon P150, softening point: about 152°C, manufactured by Yasuhara Chemical Co., Ltd.) with 300 parts by weight of toluene.

Production Examples 2 to 8 (Production of adhesive compositions (A-2) to (A-8))
Adhesive compositions (A-2) to (A-8) were produced in the same manner as Production Example 1 except that the compositions shown in Table 1 were used. In addition, in Production Example 8, the amount of light-diffusing fine particles shown in Table 1 below was added to 100 parts by weight of the adhesive composition. The amount of the tackifying resin added is based on 100 parts by weight of the base polymer (rubber-based polymer).

In Table 1,
SEPS is a styrene-ethylene-propylene-styrene block copolymer (trade name: SEPTON 2063, styrene content: 13%, manufactured by Kuraray Co., Ltd.),
PIB is polyisobutylene (trade name: OPPANOL B80, weight average molecular weight (Mw): approximately 750,000, manufactured by BASF),
BR is butyl rubber (trade name: JSR BUTYL 365, viscosity average molecular weight (Mv): approximately 350,000, manufactured by JSR Corporation),
Clearon is a terpene polymer hydride (product name: Clearon P150, softening point: approximately 152°C, manufactured by Yasuhara Chemical Co., Ltd.),
Hydrogenated terpene phenol is manufactured by Yasuhara Chemical Co., Ltd., trade name: YS Polystar UH115, softening point: approximately 115°C,
The light-diffusing fine particles are silicone resin fine particles (trade name: Tospearl 145, volume average particle diameter: 4 μm, refractive index: 1.43, silicone resin fine particles, manufactured by Momentive Performance Materials).

The moisture permeability in Table 1 was measured by the following method.
(Method for measuring moisture permeability)
Using the adhesive compositions (A-1) to (A-8) obtained in Production Examples 1 to 8, the thickness of the adhesive layer was 50 μm according to the method described in Example 1 below. An adhesive sheet was formed. One of the release liners of the pressure-sensitive adhesive sheet was peeled off to expose the pressure-sensitive adhesive surface, and the pressure-sensitive adhesive sheet was bonded to a triacetyl cellulose film (TAC film, thickness 25 μm, manufactured by Konica Minolta, Inc.) using the pressure-sensitive adhesive surface. Then, the other release liner was peeled off to obtain a sample for measurement.
Next, using this measurement sample, moisture permeability (water vapor permeability) was measured under the following conditions by a moisture permeability test method (cup method, according to JIS Z 0208).
Measurement temperature: 40℃
Relative humidity: 92%
Measurement time: 24 hours A constant temperature and humidity chamber was used during the measurement.

Production example 9 (manufacture of polarizing film)
In order to produce a thin polarizing film, first, a laminate in which a 9 μm thick polyvinyl alcohol (PVA) layer is formed on an amorphous polyethylene terephthalate (PET) base material is stretched by aerial assisted stretching at a stretching temperature of 130°C. was generated. Next, the stretched laminate is dyed to produce a colored laminate, and the colored laminate is further stretched in boric acid solution at a stretching temperature of 65°C to an amorphous PET base material so that the total stretching ratio is 5.94 times. An optical film laminate was produced that included a 4 μm thick PVA layer stretched together. Through such two-stage stretching, the PVA molecules of the PVA layer formed on the amorphous PET base material are highly oriented, and the iodine adsorbed during dyeing is oriented in one direction as a polyiodine ion complex. An optical film laminate containing a 5 μm thick PVA layer constituting a highly functional polarizing film (polarizer) was produced.

While applying a polyvinyl alcohol adhesive to the surface of the polarizing film (polarizer, thickness: 5 μm) of the optical film laminate related to the polarizer so that the adhesive layer has a thickness of 0.1 μm, a transparent After laminating a protective film (corona-treated (meth)acrylic resin film having a lactone ring structure with a thickness of 20 μm), drying was performed at 50° C. for 5 minutes. Next, the amorphous PET base material was peeled off to produce a single-protection polarizing film using a thin polarizer.

Production Example 10 (Preparation of adhesive layer (B-1))
In a separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas introduction tube, as monomer components, 99 parts by weight of butyl acrylate (BA), 1 part by weight of 4-hydroxybutyl acrylate (4HBA), and as a polymerization initiator were added. After adding 0.2 parts by weight of azobisisobutyronitrile and ethyl acetate as a polymerization solvent so that the solid content was 20%, nitrogen gas was flowed and nitrogen substitution was performed for about 1 hour while stirring. Thereafter, the flask was heated to 60° C. and reacted for 7 hours to obtain an acrylic polymer having a weight average molecular weight (Mw) of 1.1 million. To the above acrylic polymer solution (solid content: 100 parts by weight), 0.8 parts by weight of trimethylolpropane tolylene diisocyanate (trade name: Coronate L, manufactured by Nippon Polyurethane Industries, Ltd.) as an isocyanate crosslinking agent, and a silane coupling agent. (Product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 part by weight was added to prepare an adhesive composition (B-1). The adhesive composition (B-1) prepared above was applied onto a polyethylene terephthalate release liner having a thickness of 38 μm so that the thickness after drying would be 5 μm, 10 μm, and 20 μm, and the mixture was heated at 60° C. under normal pressure. The adhesive layer (B-1) having each thickness (5 μm, 10 μm, and 20 μm) was prepared by heating and drying for 1 minute and at 150° C. for 1 minute. The moisture permeability of the adhesive layer B was 1400 g/(m ² ·24 h). The moisture permeability was measured in the same manner as for adhesive layer A.

Example 1
The adhesive composition (A-1) obtained in Production Example 1 was applied to the release-treated side of a 38 μm thick polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.) whose one side was release-treated with silicone. A coating layer was formed by coating to a final thickness of 5 μm. Next, the coating layer was dried at 130° C. for 2 minutes to form an adhesive layer (A-1) to produce an adhesive sheet. In addition, on the adhesive surface of the adhesive sheet, a 38 μm thick polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.) whose one side has been subjected to a release treatment with silicone is placed so that the release treatment surface and the adhesive layer are in contact with each other. I pasted it like this. The polyester film coated on both sides of the adhesive layer functions as a release liner (separator).

One release liner of the adhesive sheet is peeled off and laminated onto a brightness enhancement film (trade name: D-BEF, manufactured by 3M) to form a brightness enhancement film with adhesive layer A (adhesive layer (A-1)). / brightness enhancement film) was formed.

The adhesive layer (B-1) with a thickness of 20 μm obtained in Production Example 10 was applied to one side (transparent protective film side) of the single-protection polarizing film (size: length 150 mm x width 70 mm) obtained in Production Example 9. By transferring, a polarizing film with adhesive layer B (release liner/adhesive layer (B-1)/transparent protective film/polarizer) was obtained.

The release liner of the adhesive layer A of the brightness enhancement film with adhesive layer A is peeled off, and the adhesive layer A and the polarizer are laminated on the polarizer of the polarizing film with adhesive layer B so that the adhesive layer A and the polarizer are in contact with each other to produce an optical member. I got it. The release liner of adhesive layer B was left as a separator. The structure of the obtained optical member was release liner (separator)/adhesive layer (B-1)/transparent protective film/polarizer/adhesive layer (A-1)/brightness enhancement film.

Examples 2 to 23, Comparative Examples 1 to 5
In Example 1, as shown in Table 2, an optical member was formed in the same manner as in Example 1, except that the type and thickness of the adhesive layer A were changed. In Comparative Examples 1 to 3, the adhesive layer (B-1) of each thickness obtained in Production Example 10 was used as the adhesive layer A. Moreover, the haze value of the light-diffusing adhesive layer of Examples 22 and 23 was measured by the following method.

<Haze value>
The haze value of the light-diffusing adhesive layer used in Examples 22 and 23 was measured using a haze meter (consumption name: HN-150, manufactured by Murakami Color Science Institute Co., Ltd.) according to the method specified in JIS 7136. .

Example 24
One side of the release liner of the pressure-sensitive adhesive sheet of the pressure-sensitive adhesive layer (A-1) obtained in Example 1 was peeled off, and one side ( Transfer the adhesive layer (A-1) onto the polarizer side) to obtain a polarizing film with an adhesive layer (transparent protective film/polarizer/adhesive layer (A-1)/release liner (separator)). Ta.

Examples 25-28
In Example 24, as shown in Table 2, a polarizing film with an adhesive layer was formed in the same manner as in Example 24, except that the type of adhesive layer A was changed.

Comparative example 6
Transfer the adhesive layer (B-1) with a thickness of 5 μm obtained in Production Example 10 to one side (polarizer side) of the single-protection polarizing film (size: 150 mm long x 70 mm wide) obtained in Production Example 9. As a result, a polarizing film with adhesive layer B (release liner (separator)/adhesive layer (B-1)/polarizer/transparent protective film) was obtained.

Comparative example 7
Transfer the 20 μm thick adhesive layer (B-1) obtained in Production Example 10 to one side (polarizer side) of the single-protection polarizing film (size: 150 mm long x 70 mm wide) obtained in Production Example 9. As a result, a polarizing film with adhesive layer B (release liner (separator)/adhesive layer (B-1)/polarizer/transparent protective film) was obtained.

Optical members obtained in Examples 1 to 23 and Comparative Examples 1 to 5 (measurement sample: with separator (release liner)), polarized light with adhesive layer obtained in Examples 24 to 28, Comparative Examples 6 and 7 The following evaluations were performed on the film (measurement sample: with separator (release liner)). The evaluation results are shown in Table 2.

<Color loss in the corner>
A test piece (50 mm x 50 mm) was cut out from the pressure-sensitive adhesive layer-attached polarizing film obtained in Examples and Comparative Examples, with two sides facing each other in the direction perpendicular to the stretching direction and in the stretching direction. For the optical members of Examples 1 to 23 and Comparative Examples 1 to 5, the separator on adhesive layer B was peeled off, the test piece was bonded to a glass plate, and this was placed in an oven at 60°C and 90% humidity for 300 hours. After being left to humidify, the polarizing film was placed in a crossed nicol state with a standard polarizing plate, and the state of color loss at the corners of the humidified polarizing film was examined using a microscope. For the adhesive layer-attached polarizing films of Examples 24 to 28 and Comparative Examples 6 and 7, the separator on the adhesive layer A was peeled off, the test piece was attached to a glass plate, and the color loss state at the corner was observed in the same manner as above. was examined using a microscope. Specifically, the size of color loss (color loss amount: μm) from the edge of the polarizing film was measured. Using MX61L manufactured by Olympus as a microscope, the amount of color loss was measured from an image taken at a magnification of 10 times. When measurements were taken at multiple locations, the largest amount was taken as the amount of color loss. Note that the color-bleached area has extremely low polarizing properties and does not substantially function as a polarizing plate, so the amount of color-bleaching is preferably 200 μm or less, more preferably 100 μm, and even more preferably 50 μm or less. be.

<Durability>
The optical members or adhesive layer-attached polarizing films obtained in Examples and Comparative Examples were heated at 80°C and 60°C/90% R. H. After being placed in the environment for 300 hours, the condition was observed visually or using a magnifying glass (20x magnification). Evaluation was made according to the following evaluation criteria.
◎: No defects (foaming, peeling, etc.) were observed even when checked with a magnifying glass.
〇: No defects could be confirmed visually, but when checked with a magnifying glass, there were some defects that did not pose a problem for use.
×: Defects were visually confirmed.

In Table 2, (A-1) to (A-8) represent the adhesive compositions (A-1) to (A-8) obtained in Production Examples 1 to 8, and (B-1) represent the adhesive compositions (A-1) to (A-8) obtained in Production Examples 1 to 8. In the adhesive composition (B-1) obtained in Production Example 10, D-BEF indicates a brightness enhancement film (trade name: D-BEF, manufactured by 3M Corporation).

The content (%) of light-diffusing fine particles in Table 2 is the content of light-diffusing fine particles in the light-diffusing adhesive layer.

1 Polarizing film with adhesive layer 2 Polarizing film 3 Adhesive layer A (or light diffusion adhesive layer A1)
4 Polarizer 5 Transparent protective film 6 Brightness enhancement film 7 Prism sheet 10 Optical member

Claims (11)

A polarizing film with an adhesive layer for the backlight side of an image display device having a polarizing film and an adhesive layer A provided on the polarizing film,
The polarizing film is a single-sided protective polarizing film having a transparent protective film only on one side of a polarizer having a thickness of 10 μm or less, and the adhesive layer A is on the side of the polarizer that does not have the transparent protective film. It is provided,
A polarizing film with an adhesive layer, wherein the adhesive layer A has a moisture permeability of 100 g/(m ² ·24 h) or less and a thickness of 30 μm or less. The polarizing film with an adhesive layer according to claim 1, wherein the adhesive layer A is an adhesive layer containing a rubber-based polymer as a main component. The polarizing film with an adhesive layer according to claim 2, wherein the rubber-based polymer is one or more rubber-based polymers selected from the group consisting of a styrene-based thermoplastic elastomer, polyisobutylene, and butyl rubber. . The polarizing film with an adhesive layer according to claim 2 or 3, wherein the adhesive layer A further contains a tackifying resin. 5. The polarizing film with an adhesive layer according to claim 1, wherein the adhesive layer A is a light-diffusing adhesive layer A1 containing light-diffusing fine particles. The polarizing film with an adhesive layer according to claim 5, wherein the light-diffusing adhesive layer A1 has a haze of 10 to 95%. The polarizing film with an adhesive layer according to claim 5 or 6, wherein the light-diffusing fine particles are silicone resin fine particles or styrene resin fine particles. The polarizing film with an adhesive layer according to any one of claims 5 to 7, wherein the light-diffusing fine particles have a volume average particle diameter of 1 to 4 μm. An optical member comprising the polarizing film with an adhesive layer according to any one of claims 1 to 8, and a brightness enhancing film provided on the adhesive layer side of the polarizing film with an adhesive layer. 10. The optical member according to claim 9, further comprising a prism sheet provided on the side of the brightness-enhancing film that does not have the adhesive layer-attached polarizing film. An image display device comprising one or more members selected from the group consisting of the polarizing film with an adhesive layer according to claims 1 to 8, and the optical member according to claims 9 and 10.