JP6852967B2 - Polarizing film with adhesive layer, optical members, 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 weight reduction and thinning in image display devices such as liquid crystal display devices, and it is possible to reduce the weight and weight of various optical members such as polarizing films used in image display devices. It has been requested, and various methods for producing a thin polarizing film have been studied.

As a method for producing a thin polarizing film, for example, a thin polyvinyl alcohol (PVA) -based polymer layer formed on a resin base material having a certain thickness is uniaxially stretched in a state of being integrated with the resin base material to be thin. A method of forming a polarizing film on a resin base material (see, for example, Patent Document 1), or a laminated film in which a resin layer made of PVA resin is formed on one surface of a base material film at a free end at a specific draw ratio. A method is known in which a stretched film is obtained by longitudinally uniaxially stretching, and the stretched film is dyed with a bicolor dye to form a thin polarizer (see, for example, Patent Document 2).

Japanese Patent No. 4691025 Japanese Patent No. 5048120

The thin polarizing films obtained in Patent Documents 1 and 2 are single-sided protective polarizing films in which one side of the polarizer is protected by a transparent protective film, and an adhesive is applied to the polarizing element side of the single-sided protective polarizing film. It can be incorporated into an image display device by being attached to various optical members or the like via a layer.

Although the single-sided protective polarizing film is excellent from the viewpoint of thinning, when the single-sided protective polarizing film is exposed to a high-temperature humidified environment with the single-sided protective polarizing film attached to an adherend, moisture is transferred to the polarizer. There is a problem that the polarizer deteriorates (depolarization occurs).

Therefore, an object of the present invention is to provide a polarizing film with an adhesive layer capable of suppressing deterioration of the polarizer of the one-sided protective 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 in which the pressure-sensitive adhesive layer of the polarizing film with an adhesive layer is a light diffusing pressure-sensitive 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 diligent studies to solve the above problems, the present inventors have found the following polarizing film with an adhesive layer, and have completed the present invention.

That is, the present invention comprises a polarizing film and a polarizing film with an adhesive layer having an adhesive layer A provided on the polarizing film.
The polarizing film is a single-sided protective polarizing film having a transparent protective film on only one side of a polarizing element having a thickness of 10 μm or less, and the pressure-sensitive adhesive layer A is on the side of the polarizing element that does not have the transparent protective film. It is provided,
The pressure-sensitive adhesive layer A moisture permeability is at 300g ^/ (m 2 · 24h) or less, about polarizing film pressure-sensitive adhesive layer, wherein the thickness is 50μm or less.

The pressure-sensitive adhesive layer A is preferably a pressure-sensitive adhesive layer containing a rubber-based polymer as a main component.

The rubber-based polymer is preferably one or more rubber-based polymers selected from the group consisting of styrene-based thermoplastic elastomers, polyisobutylene, and butyl rubber.

It is preferable that the pressure-sensitive adhesive layer A further contains a pressure-imparting resin.

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

The haze of the light diffusing pressure-sensitive adhesive layer A1 is preferably 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 size of the light diffusing fine particles is preferably 1 to 4 μm.

The present invention also relates to an optical member having the polarizing film with the pressure-sensitive adhesive layer and a brightness improving film provided on the pressure-sensitive adhesive layer A or the pressure-sensitive adhesive layer A1 side of the polarizing film with the pressure-sensitive adhesive layer. ..

A prism sheet can be further provided on the side of the optical member that does not have the polarizing film with the pressure-sensitive adhesive layer of the brightness improving film.

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

Polarizing film pressure-sensitive adhesive layer of the present invention, because it is intended to use a single protective polarizing film are those can be made thinner, and, in moisture permeability of the pressure-sensitive adhesive layer A is 300g / (m 2 · ^24h) or less Moreover, since the thickness is 50 μm or less, deterioration of the polarizer in a high-temperature humidification environment can be suppressed. That is, in the polarizing film with a pressure-sensitive adhesive layer of the present invention, since the pressure-sensitive adhesive layer A has a low humidity permeability and a thickness of 50 μm or less, moisture is contained in the polarizer even when exposed to a high-temperature humidification environment. Can be suppressed from migrating, and as a result, depolarization due to deterioration of the polarizer can be suppressed. Further, when the pressure-sensitive adhesive layer A is the light-diffusing pressure-sensitive adhesive layer A1, the polarizing film with the pressure-sensitive adhesive layer of the present invention has a light-diffusing function, and therefore can be used instead of the diffusion sheet used in the image display device. The image display device can be made thinner. Further, by using the polarizing film with an adhesive layer having a light diffusing function on the backlight side, it is possible to eliminate the bias of the light from the backlight and to obtain a more uniform display. Further, since the optical member and the image display device of the present invention include the polarizing film with the pressure-sensitive adhesive layer of the present invention, they have high reliability.

It is sectional drawing which shows typically one Embodiment of the polarizing film with an adhesive layer of this invention. It is sectional drawing which shows typically one Embodiment of the optical member of this invention. It is sectional drawing which shows typically one Embodiment of the optical member of this invention.

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

The configuration of the polarizing film with an adhesive layer of the present invention will be described in detail with reference to the drawings. The dimensions of each configuration in FIG. 1 show an example thereof, and the present invention is not limited thereto.

As shown in FIG. 1, the polarizing film 1 with an adhesive layer of the present invention has an adhesive layer A (3 in FIG. 1) on at least one side of the polarizing film 2. Further, the polarizing film 2 has a transparent protective film 5 only on one side of the polarizing element 4, and the pressure-sensitive adhesive layer A (3) is a side of the polarizing element 4 that does not have the transparent protective film 5. (That is, it suffices if it is provided on the polarizer 4 side). The polarizer 4 and the pressure-sensitive adhesive layer A (3) do not necessarily have to be in contact with each other, but from the viewpoint that the effects of the present invention can be remarkably exhibited, they are preferably in contact with each other.

Further, the pressure-sensitive adhesive layer B (not shown) may be further provided on the side of the transparent protective film 5 that does not have the polarizer 4. The pressure-sensitive adhesive layer B provided on the transparent protective film 5 may be the pressure-sensitive adhesive layer A having the specific moisture permeability, or may be another pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer B will be described later.

(1) Adhesive layer A
Pressure-sensitive adhesive layer A used in the present invention, moisture permeability is at 300g ^/ (m 2 · 24h) or less, wherein the thickness is 50μm or less.

Pressure-sensitive adhesive layer A used in the present invention, moisture permeability is not more 300g / (m 2 · ^24h) or less, due to the low permeability of water vapor, which can suppress the polarizer by moisture or the like to deteriorate Is. The moisture permeation was measured at 40 ° C. and 92% R.I. H. It is the water vapor transmittance (moisture permeability) under the conditions, and the measuring method thereof can be measured by the method described in Examples.

The moisture ^{permeability, 300g / (m 2 · 24h} ) or less, is preferably 200g ^/ (m 2 · 24h) or less, still more preferably 100g ^/ (m 2 · 24h) or less, 60 g / ^(m 2 · 24h) or less is particularly preferred. Although permeability lower limit of the humidity is not particularly limited, ideally, it does not at all transmitted through the water vapor ^{(i.e., 0g / (m 2 · 24h} )) is preferable. When the moisture permeability of the pressure-sensitive adhesive layer A is within the above range, it is possible to suppress the transfer of moisture to the polarizer, and it is possible to suppress the elimination of polarization due to the deterioration of the polarizer, and the pressure-sensitive adhesive has high optical reliability. It can be a layered polarizing film.

The thickness of the pressure-sensitive 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 further preferably 10 μm or less. The lower limit of the thickness of the pressure-sensitive 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 described above, the pressure-sensitive 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 is possible to suppress the transfer of water to the polarizer in a high-temperature humidification environment. .. As a result, it is possible to suppress depolarization due to deterioration of the polarizer, and it is possible to obtain a polarizing film with an adhesive layer having high optical reliability.

Moisture transfer of the single-sided protective film to the polarizer is performed from the adhesive surface of the pressure-sensitive adhesive layer A provided on the single-sided protective polarizing film (that is, the surface of the pressure-sensitive adhesive layer A opposite to the side on which the polarizer is provided). Moisture transfer and water transfer from the side surface of the pressure-sensitive adhesive layer A can be considered. Normally, an adherend such as a display panel or a glass plate is attached to the side of the pressure-sensitive adhesive layer A opposite to the side having a polarizing element, and moisture transfer from the surface direction of the pressure-sensitive adhesive layer A is suppressed to some extent. However, it was difficult to suppress the transfer of water from the side surface portion of the pressure-sensitive adhesive layer A. Since the pressure-sensitive 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 a side surface portion of the pressure-sensitive adhesive layer A, it is possible to suppress the amount of water transferred from the side surface portion. It is possible to suppress polarization elimination due to deterioration of the polarizer.

The pressure-sensitive adhesive layer A used in the present invention may have a moisture permeability and a thickness within the above ranges, and its composition is not limited. For example, a rubber-based pressure-sensitive adhesive composition, an acrylic-based pressure-sensitive adhesive composition, and silicone. Those formed from a based pressure-sensitive adhesive composition, a urethane-based pressure-sensitive adhesive composition, and the like can be appropriately used. Among these, a rubber-based pressure-sensitive adhesive composition using a rubber-based polymer as a base polymer is preferable from the viewpoint of moisture permeability. The pressure-sensitive adhesive layer A used in the present invention preferably contains the rubber-based polymer as a main component. Here, the "main component" means that the rubber-based polymer is contained in the pressure-sensitive adhesive layer A (or in the total solid content of the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer A) in an amount of 40% by weight or more.

The rubber-based polymer is a polymer that exhibits rubber elasticity in a temperature range near 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.

Examples of the synthetic rubber include polyisobutylene (PIB), butadiene rubber (BR), butyl rubber (IIR), isoprene rubber (IR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). , Butethylene-isoprene-styrene random copolymer, isoprene-styrene random copolymer, EPR (binary ethylene-propylene rubber), EPT (ternary ethylene-propylene rubber), acrylic rubber, urethane rubber, etc. Can be done. Among these, polyisobutylene (PIB) and butyl rubber (IIR) are preferable, and polyisobutylene (PIB) is more preferable, from the viewpoint of transparency and light resistance.

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

The pressure-sensitive adhesive composition contains a rubber-based polymer as a base polymer, and the content of the rubber-based polymer in the pressure-sensitive adhesive composition is preferably 40% by weight or more, preferably 50% by weight or more. More preferably, it 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 100% by weight or less, preferably 95% by weight or less.

The pressure-sensitive adhesive composition preferably further contains a tack-imparting resin from the viewpoint of adhesiveness to an adherend such as a polarizer, an optical film, glass, and a display panel.

Examples of the tackifier resin include terpene-based tackifier resins, phenol-based tackifier resins, rosin-based tackifier resins, petroleum resin-based tackifier resins, and the like, and these may be used alone or in combination of two or more. Can be used in combination. Among these, the terpene-based tackifier resin is preferable from the viewpoint of transparency and adhesiveness.

Examples of the terpene-based tackifier resin include terpene polymers such as α-pinene polymer, β-pinene polymer, and dipentene polymer, and terpene polymers modified (phenolic modification, styrene modification, aromatic modification, hydrogen). Examples thereof include modified terpene resins (additional 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 referred to here include hydrides of terpene polymers, other modified terpene resins, and hydrides of terpene phenol resins.

As the tackifying resin, for example, commercially available products such as Clearon series and Polystar series manufactured by Yasuhara Chemical Co., Ltd., Superester series, Pencel series and Pine Crystal series manufactured by Arakawa Chemical Industry Co., Ltd. can be used. ..

The softening point (softening temperature) of the tackifier resin is not particularly limited, but for example, the softening point is preferably about 80 ° C. or higher, and 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, for example, about 200 ° C. or lower, and preferably about 180 ° C. or lower. The softening point of the tackifier resin referred to here is defined as a value measured by the softening point test method (ring ball method) specified in any of JIS K5902 and JIS K2207.

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

In addition, an organic solvent can be added to the pressure-sensitive adhesive composition as a diluent. The diluent is not particularly limited, and examples thereof include hexane, heptane, toluene, xylene, and dimethyl ether, and these may be used alone or in combination of two or more. it can. Of these, toluene is preferred.

The amount of the diluent added is not particularly limited, but is preferably about 50 to 500 parts by weight, preferably about 100 to 300 parts by weight, based on 100 parts by weight of the base polymer in the pressure-sensitive adhesive composition. More preferably. When the amount of the diluent added is within the above range, it is preferable from the viewpoint of coatability to the support or the like.

The pressure-sensitive adhesive composition may further contain any suitable additive. Specific examples of the additive include a cross-linking agent (for example, a polyisocyanate, an epoxy compound, an alkyl etherified melamine compound, etc.), a plasticizer, a filler, an anti-aging agent, and the like. The type, combination, addition amount, and the like of the additives added to the pressure-sensitive adhesive composition can be appropriately set according to the purpose. The content (total amount) of the additive in the pressure-sensitive adhesive composition is preferably 50% by weight or less, more preferably 40% by weight or less, and further preferably 30% by weight or less.

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

Any suitable light diffusing fine particles can be used. Specific examples include inorganic fine particles and polymer fine particles, and among these, polymer fine particles are preferable.

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

The shape of the light diffusing fine particles can be, for example, a true spherical shape, a flat shape, or an indefinite shape. The light diffusing fine particles may be used alone or in combination of two or more.

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 "refractive index of the pressure-sensitive adhesive composition" is the refractive index of the pressure-sensitive adhesive composition (that is, the pressure-sensitive adhesive composition before adding the light-diffusing fine particles) that does not contain 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. When the refractive index of the light diffusing fine particles is in the above range, the difference in refractive index from the pressure-sensitive adhesive composition can be set in a desired range, and as a result, the light diffusing pressure-sensitive adhesive layer A1 having a desired haze value is obtained. It is preferable because it can be used.

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

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

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

The haze of the light diffusing pressure-sensitive adhesive layer A1 is not particularly limited, but is preferably 10 to 95%, more preferably 20 to 85%, and further preferably 30 to 70%. preferable. It is preferable to set the haze value in the above range because desired diffusion performance can be obtained and the occurrence of moire and glare can be satisfactorily suppressed. The light diffusing performance of the light diffusing pressure-sensitive adhesive layer A1 can be controlled by adjusting the constituent material of the matrix (adhesive), the constituent material of the light diffusing fine particles, the volume average particle size, the blending amount, and the like.

The method for forming the pressure-sensitive 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 polarizing element having a thickness of 10 μm or less is used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. It is preferable that such a thin polarizing element has less uneven thickness, excellent visibility, excellent durability because there is little dimensional change, and the thickness of the polarizing film can be reduced.

Typical examples of the thin polarizing element include JP-A-51-069644 and JP-A-2000-338329, International Publication No. 2010/100917 Pamphlet, and JP-A-2014-59328 and JP-A-2014-59328. Examples thereof include the thin polarizing film described in Japanese Patent Application Laid-Open No. 2012-73563. 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 any trouble such as breakage due to stretching because it is supported by the stretching resin base material.

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. Alternatively, those obtained by a production method including a step of stretching in an aqueous boric acid solution as described in JP-A-2014-509328 and JP-A-2012-073563 are preferable, and in particular, JP-A-2014-059328 and JP-A-2014-059328. It is preferably obtained by a production method including a step of auxiliary stretching in the air before stretching in an aqueous boric acid solution described in JP2012-073563.

As the material for forming the transparent protective film provided on one side of the polarizer, 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 polystyrene polymers. In addition, polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, polyolefin-based polymers such as ethylene / propylene copolymers, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamide, imide-based polymers, and sulfone-based 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 Blends of the polymers and the like are also mentioned as examples of polymers forming the transparent protective film. The transparent protective film can also be formed as a cured layer of a thermosetting type or ultraviolet curable type resin such as acrylic type, urethane type, acrylic urethane type, epoxy type and silicone type.

The thickness of the protective film can be appropriately determined, but is generally about 1 to 500 μm in terms of workability such as strength and handleability, and thin film property.

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

The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a hard coat layer, antireflection treatment, anti-sticking treatment, or treatment for the purpose of diffusion or anti-glare.

(3) Polarizing film with pressure-sensitive adhesive layer The polarizing film with pressure-sensitive adhesive layer of the present invention is obtained by directly applying the pressure-sensitive adhesive composition to the polarizer of the single-sided protective polarizing film and removing the solvent or the like by heating and drying. , The pressure-sensitive adhesive layer A (or A1) can be formed on the polarizer. Further, the pressure-sensitive adhesive layer A (or A1) formed on the support or the like can be transferred onto the polarizer of the single-sided protective polarizing film to form a polarizing film with a pressure-sensitive adhesive layer.

Various methods are used as the method for applying 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 a method such as an extrusion coating method.

The heating and drying temperature is preferably about 30 ° C. to 200 ° C., more preferably 40 ° C. to 180 ° C., and even more preferably 80 ° C. to 150 ° C. By setting the heating temperature in the above range, the pressure-sensitive adhesive layer A (or A1) having excellent adhesive properties can be obtained. As the drying time, an appropriate time can be adopted as appropriate. 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 peeled sheet (separator) can be used. A silicone release liner is preferably used as the release-treated sheet.

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 or the like can be mentioned, 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 and the like can be mentioned.

The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. If necessary, the separator may be released from a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agent, silica powder, or the like, as well as antifouling treatment, coating type, kneading type, or vapor deposition. It is also possible to perform antistatic treatment on the mold and the like. In particular, the peelability from the pressure-sensitive adhesive layer A (or A1) 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.

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

Since the polarizing film with an adhesive layer of the present invention uses a single-protective polarizing film having a polarizer thickness of 10 μm or less, the entire polarizing film with an adhesive layer can be thinned. The thickness of the polarizing film with the pressure-sensitive adhesive layer can be 35 μm or less.

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

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

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 the ester group. The alkyl (meth) acrylate refers to an alkyl acrylate and / or an alkyl methacrylate, and has the same meaning as the (meth) of the present invention.

Examples of the alkyl (meth) acrylate include those having a linear or branched chain alkyl group having 4 to 24 carbon atoms. The alkyl (meth) acrylate may be used alone or in combination of two or more.

The (meth) acrylic polymer according to the pressure-sensitive adhesive layer B preferably contains the largest amount of butyl acrylate as a monomer unit from the viewpoint of processability, storage property, and durability by controlling the storage elastic modulus.

In the present invention, the alkyl (meth) acrylate having an alkyl group having 4 to 24 carbon atoms at the ester terminal is 40% by weight or more based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. It is preferable, more 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 copolymerization monomer other than the alkyl (meth) acrylate as a monofunctional monomer component. Examples of such a copolymerization monomer include a cyclic nitrogen-containing monomer, a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and a monomer having a cyclic ether group.

In the present invention, the copolymerized monomer can be used as the balance 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. It is more preferably 50% by weight or less, still more preferably 40% by weight or less.

In addition to the above, various copolymerized monomers having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group, a silane-based monomer containing a silicon atom, and the like can also be used. ..

Further, in addition to the monofunctional monomer exemplified above, the monomer component forming the (meth) acrylic polymer used in the present invention is polyfunctional as necessary in order to adjust the cohesive force of the pressure-sensitive adhesive. It can contain a monomer.

The amount of the polyfunctional monomer used varies depending on its molecular weight, the number of functional groups, and the like, 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 100 parts by weight of the total 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, and more preferably 0.001 parts by weight or more. When the amount of the polyfunctional monomer used is within the above range, the 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, bulk polymerization, and various radical polymerizations such as emulsion polymerization 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 known ones 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, when the (meth) acrylic polymer is produced by active energy ray polymerization, it can be produced by polymerizing the monomer component by irradiating it with active energy rays such as electron beam and ultraviolet rays. When the active energy ray polymerization is carried out by an electron beam, it is not particularly necessary to include a photopolymerization initiator in the monomer component, but particularly when the active energy ray polymerization is carried out by ultraviolet polymerization. A photopolymerization initiator can be contained in the monomer component because of the advantage that the polymerization time can be shortened. The photopolymerization initiator may be used alone or in combination of two or more. As the monomer component, a syrup obtained by partially polymerizing in advance can be used for irradiation.

The photopolymerization initiator is not particularly limited, and known photopolymerization initiators can be appropriately selected and used. As the addition amount, it can be used in an amount that is usually used.

The pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer B may contain a cross-linking agent. Examples of the cross-linking agent include isocyanate-based cross-linking agent, epoxy-based cross-linking agent, silicone-based cross-linking agent, oxazoline-based cross-linking agent, aziridine-based cross-linking agent, silane-based cross-linking agent, alkyl etherified melamine-based cross-linking agent, metal chelate-based cross-linking agent, and excess. Includes cross-linking agents such as oxides. The cross-linking agent may be used alone or in combination of two or more. As the cross-linking agent, an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent are preferably used.

The above-mentioned cross-linking agent may be used alone or in combination of two or more, but the content as a whole is based on 100 parts by weight of the (meth) acrylic polymer. The cross-linking agent is preferably contained in the range of 0.01 to 5 parts by weight. The content of the cross-linking agent is preferably 0.01 to 4 parts by weight, more preferably 0.0 to 3 parts by weight.

Further, as the cross-linking agent, an organic cross-linking agent or a polyfunctional metal chelate may be used in combination.

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

Further, the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer B can contain a silane coupling agent. The blending amount of the silane coupling agent is preferably 1 part by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer, more preferably 0.01 to 1 part by weight, still more preferably 0.02 to 0. 6.6 parts by weight.

Preferred silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4 epoxycyclohexyl). ) Epoxy group-containing silane coupling agent such as ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1) , 3-Dimethylbutylidene) Propylamine, N-phenyl-γ-aminopropyltrimethoxysilane and other amino group-containing silane coupling agents, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane and the like. Examples thereof include (meth) acrylic group-containing silane coupling agents and isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane.

Further, the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer B may contain other known additives, for example, a polyether compound of a polyalkylene glycol such as polypropylene glycol, a colorant, a pigment and the like. Powders, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic The filler, metal powder, particles, foil, etc. of the above can be appropriately added depending on the intended use. Further, a redox system to which a reducing agent is added may be adopted within a controllable range.

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

Various methods are used as the method for applying 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 a method such as an extrusion coating method.

The heating and drying temperature is preferably 40 ° C. to 200 ° C., more preferably 50 ° C. to 180 ° C., and particularly preferably 60 ° C. to 170 ° C. By setting the heating temperature in the above range, the pressure-sensitive adhesive layer B 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.

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

Further, the pressure-sensitive 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 the present specification can be appropriately used.

The pressure-sensitive adhesive layer B formed on the transparent protective film of the polarizing film may be protected by a sheet (separator) whose adhesive surface has been peeled off until it is put into practical use. In practical use, the peeled sheet is peeled off. As the separator, those described in the present specification can be appropriately used.

The thickness of the pressure-sensitive adhesive layer B is not particularly limited, but is preferably 30 μm or less, more preferably 1 to 25 μm, further preferably 5 to 25 μm, and 10 to 20 μm. It is particularly preferable to have.

2. Optical member The optical member of the present invention is characterized by having the polarizing film with an adhesive layer and a brightness improving 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 improving film 6 may be directly bonded via the pressure-sensitive adhesive layer A (3) of the polarizing film 1 with the pressure-sensitive adhesive layer, and other It may be laminated via a layer. Further, as shown in FIG. 3, the optical member 10 of the present invention has a prism on the side of the brightness improving film 6 that does not have the polarizing film 1 with an adhesive layer, via an adhesive layer (not shown) or the like. The sheets 7 can be further laminated. The prism sheet 7 typically has a substrate and a prism portion.

Examples of the brightness improving film 6 include a reflective polarizing plate. The reflective polarizing plate is a linearly polarized light separation type polarizing plate. Typical examples are a grid-type polarizing plate, a multilayer thin film laminated polarizing plate made of two or more materials having different refractive indexes, a vapor-deposited multilayer thin film having different refractive indexes, and a birefringent layer multilayer thin film made of two or more kinds of materials having different refractive indexes. Laminates, stretched two or more resin laminates using two or more resins with different refractive indexes, and polarizing plates that separate linearly polarized light by reflecting / transmitting it in the orthogonal axial direction (linearly polarized light separation). Type reflective polarizing plate). Among these, a linearly polarized light separation 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 Ltd. or the trade name "Nipox APCF" manufactured by Nitto Denko KK can be used.

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

When the pressure-sensitive adhesive layer A is a diffusion pressure-sensitive adhesive layer A1, the polarizing film with a pressure-sensitive adhesive layer of the present invention has a light-diffusing function, and is therefore used in place of, for example, a diffusion sheet provided on the backlight side of an image display device. be able to. In that case, as described above, an optical member can be formed and used together with the luminance improving film or the prism sheet.

Further, when the pressure-sensitive adhesive layer A of the polarizing film with the pressure-sensitive adhesive layer of the present invention does not have a diffusion function (that is, in the case of the pressure-sensitive adhesive layer A which does not contain light-diffusing fine particles), the back of the image display device. It can be used as either a light-side or visual-viewing polarizing film.

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

Since the image display device of the present invention includes the polarizing film with an adhesive layer or an optical member, it has high reliability. Further, since the optical member of the present invention has a light diffusion function, the optical member can be used in place of the diffusion sheet provided on the backlight side, and as a result, the image display device can be thinned. , The bias of the light from the backlight can be eliminated, and a more uniform display can be obtained.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In addition, each part and% in each example is based on weight.

Production Example 1 (Production of Adhesive Composition (A-1))
100 parts by weight of a 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 tackifier resin. A pressure-sensitive adhesive composition (A-1) was prepared by mixing 10 parts by weight of a hydride (trade name: Clearlon 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 prepared in the same manner as in Production Example 1 except that the compositions shown in Table 1 were used. 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 pressure-sensitive adhesive composition. The amount of the tackifier resin added is an amount 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): about 750,000, manufactured by BASF),
BR is butyl rubber (trade name: JSR BUTYL 365, viscosity average molecular weight (Mv): about 350,000, manufactured by JSR Corporation),
Clearon is a terpene polymer hydride (trade name: Clearon P150, softening point: about 152 ° C, manufactured by Yasuhara Chemical Co., Ltd.),
Hydrogenated terpene phenol, trade name: YS Polystar UH115, softening point: about 115 ° C, manufactured by Yasuhara Chemical Co., Ltd.,
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).
Is.

The moisture permeability in Table 1 was measured by the following method.
(Measurement method of moisture permeability)
Using the pressure-sensitive adhesive compositions (A-1) to (A-8) obtained in Production Examples 1 to 8, the thickness of the pressure-sensitive adhesive layer is 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 attached to a triacetyl cellulose film (TAC film, thickness 25 μm, manufactured by Konica Minolta Co., Ltd.) by the pressure-sensitive adhesive surface. Then, the other release liner was peeled off to obtain a measurement sample.
Next, using this measurement sample, the moisture permeability (water vapor permeability) was measured by the moisture permeability test method (cup method, according to JIS Z 0208) under the following conditions.
Measurement temperature: 40 ° C
Relative humidity: 92%
Measurement time: 24 hours A constant temperature and humidity chamber was used for the measurement.

Production Example 9 (Production 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) substrate is stretched by aerial auxiliary stretching at a stretching temperature of 130 ° C. Was generated. Next, the stretched laminate was dyed to produce a colored laminate, and the colored laminate was further stretched with boric acid water at a stretching temperature of 65 ° C. to obtain a total stretching ratio of 5.94 times with an amorphous PET substrate. An optical film laminate containing a 4 μm-thick PVA layer stretched integrally was produced. The PVA molecules in the PVA layer formed on the amorphous PET substrate by such two-step stretching are highly oriented, and the iodine adsorbed by staining is highly oriented in one direction as a polyiodine ion complex. An optical film laminate containing a PVA layer having a thickness of 5 μm, which constitutes a high-performance polarizing film (polarizer), was produced.

Transparent while applying a polyvinyl alcohol-based adhesive to the surface of the polarizing film (polarizer, thickness: 5 μm) of the optical film laminate related to the polarizer so that the thickness of the adhesive layer is 0.1 μm. After attaching a protective film (a (meth) acrylic resin film having a lactone ring structure having a thickness of 20 μm and being subjected to corona treatment), the film was dried at 50 ° C. for 5 minutes. Next, the amorphous PET substrate was peeled off to prepare a single-protective polarizing film using a thin polarizing element.

Production Example 10 (Preparation of Adhesive Layer (B-1))
In a separable flask equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube, 99 parts by weight of butyl acrylate (BA) and 1 part by weight of 4-hydroxybutyl acrylate (4HBA) as a monomer component, as a polymerization initiator. After adding 0.2 parts by weight of azobisisobutyronitrile and ethyl acetate as a polymerization solvent so that the solid content became 20%, nitrogen gas was flowed and nitrogen substitution was carried out for about 1 hour with stirring. Then, 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 Industry Co., Ltd.) as an isocyanate-based cross-linking agent, a silane coupling agent (Product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 part by weight was added to prepare a pressure-sensitive adhesive composition (B-1). The prepared pressure-sensitive adhesive composition (B-1) is applied onto a polyethylene terephthalate-based release liner having a thickness of 38 μm so that the thicknesses after drying are 5 μm, 10 μm, and 20 μm, and at 60 ° C. under normal pressure. The pressure-sensitive adhesive layer (B-1) having each thickness (5 μm, 10 μm, 20 μm) was prepared by heating and drying for 1 minute and 1 minute at 150 ° C. Moisture permeability of the adhesive layer B was ^{1400g / (m 2 · 24h)} . The moisture permeability was measured by the same method as that for the pressure-sensitive adhesive layer A.

Example 1
The pressure-sensitive adhesive composition (A-1) obtained in Production Example 1 was applied to a peel-treated surface of a polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.) having a thickness of 38 μm in which one side was peel-treated with silicone. , The coating layer was formed by coating so that the final thickness was 5 μm. Next, the coating layer was dried at 130 ° C. for 2 minutes to form an adhesive layer (A-1) to prepare an adhesive sheet. Further, on the adhesive surface of the adhesive sheet, a polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.) having a thickness of 38 μm obtained by peeling one side with silicone is in contact with the peeled surface and the adhesive layer. It was pasted together. The polyester film coated on both sides of the pressure-sensitive adhesive layer functions as a release liner (separator).

One of the release liners of the adhesive sheet is peeled off and laminated on a brightness improving film (trade name: D-BEF, manufactured by 3M Co., Ltd.) to improve the brightness with the pressure-sensitive adhesive layer A (adhesive layer (A-1)). / Brightness improving film) was formed.

The 20 μm-thick adhesive layer (B-1) obtained in Production Example 10 was applied to one side (transparent protective film side) of the one-sided protective polarizing film (size: length 150 mm × width 70 mm) obtained in Production Example 9. Transferring was performed to obtain a polarizing film with a pressure-sensitive adhesive layer B (release liner / pressure-sensitive adhesive layer (B-1) / transparent protective film / polarizer).

The release liner of the pressure-sensitive adhesive layer A of the brightness improving film with the pressure-sensitive adhesive layer A is peeled off, and the pressure-sensitive adhesive layer A and the polarizing element are laminated on the polarizing element of the polarizing film with the pressure-sensitive adhesive layer B so as to be in contact with each other. Got The release liner of the pressure-sensitive adhesive layer B was left as a separator. The structure of the obtained optical member was a release liner (separator) / adhesive layer (B-1) / transparent protective film / polarizer / adhesive layer (A-1) / brightness improving 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 pressure-sensitive adhesive layer A were changed. In Comparative Examples 1 to 3, the pressure-sensitive adhesive layer (B-1) of each thickness obtained in Production Example 10 was used as the pressure-sensitive adhesive layer A. The haze value of the light diffusing pressure-sensitive 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 (consumer name: HN-150, manufactured by Murakami Color Science Laboratory Co., Ltd.) by the method specified by JIS 7136. ..

Example 24
One of the release liners of the pressure-sensitive adhesive sheet of the pressure-sensitive adhesive layer (A-1) obtained in Example 1 was peeled off, and one side of the one-sided protective polarizing film (size: length 150 mm × width 70 mm) obtained in Production Example 9 (size: length 150 mm × width 70 mm). The pressure-sensitive adhesive layer (A-1) is transferred to the polarizer side) to obtain a polarizing film with a pressure-sensitive adhesive layer (transparent protective film / polarizer / pressure-sensitive adhesive layer (A-1) / release liner (separator)). It was.

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 the pressure-sensitive adhesive layer A was changed.

Comparative Example 6
The 5 μm-thick adhesive layer (B-1) obtained in Production Example 10 is transferred to one side (polarizer side) of the one-sided protective polarizing film (size: length 150 mm × width 70 mm) obtained in Production Example 9. Then, a polarizing film with an adhesive layer B (release liner (separator) / adhesive layer (B-1) / polarizer / transparent protective film) was obtained.

Comparative Example 7
The 20 μm-thick adhesive layer (B-1) obtained in Production Example 10 is transferred to one side (polarizer side) of the one-sided protective polarizing film (size: length 150 mm × width 70 mm) obtained in Production Example 9. Then, a polarizing film with an adhesive layer B (release liner (separator) / adhesive layer (B-1) / polarizer / transparent protective film) was obtained.

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

<Color loss at corners>
From the polarizing film with the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples, a test piece (50 mm × 50 mm) having two sides opposite to each other in the direction orthogonal to the stretching direction and the stretching direction was cut out. For the optical members of Examples 1 to 23 and Comparative Examples 1 to 5, the separator on the pressure-sensitive adhesive layer B was peeled off, the test piece was attached to a glass plate, and this was placed in an oven at 60 ° C. and 90% humidity for 300 hours. When the film was left to be humidified and placed in the state of a standard polarizing plate and cross Nicol, the state of color loss at the corners of the polarizing film after humidification was examined with a microscope. For the polarizing films with the pressure-sensitive adhesive layer of Examples 24 to 28 and Comparative Examples 6 and 7, the separator on the pressure-sensitive adhesive layer A was peeled off, the test piece was attached to the glass plate, and the corners were discolored in the same manner as described above. Was examined under a microscope. Specifically, the magnitude of color loss (color loss amount: μm) from the edge of the polarizing film was measured. An MX61L manufactured by Olympus was used as a microscope, and the amount of color loss was measured from an image taken at a magnification of 10 times. When measured at multiple locations, the largest one was taken as the amount of color loss. Since the color loss region has extremely low polarization characteristics and does not substantially function as a polarizing plate, the color loss amount is preferably 200 μm or less, more preferably 100 μm, and further preferably 50 μm or less. is there.

<Durability>
The optical member or the polarizing film with an adhesive layer obtained in Examples and Comparative Examples was subjected to 80 ° C., 60 ° C./90% R. H. The state after being put into the environment for 300 hours was observed visually or using a magnifying glass (20 times). Evaluation was made according to the following evaluation criteria.
⊚: No defects (foaming, peeling, etc.) occurred even after checking with a magnifying glass.
〇: No defects could be visually confirmed, but when confirmed with a magnifying glass, there were some defects to the extent that there was no problem in use.
X: A defect was visually confirmed.

In Table 2, (A-1) to (A-8) are the pressure-sensitive adhesive compositions (A-1) to (A-8) obtained in Production Examples 1 to 8, and (B-1) is. Regarding the pressure-sensitive adhesive composition (B-1) obtained in Production Example 10, D-BEF indicates a brightness-improving film (trade name: D-BEF, manufactured by 3M Ltd.).

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

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

Claims (9)

A polarizing film with a pressure-sensitive adhesive layer having a polarizing film and a pressure-sensitive adhesive layer A provided on the polarizing film.
The polarizing film is a single-sided protective polarizing film having a transparent protective film on only one side of a polarizing element having a thickness of 10 μm or less, and the pressure-sensitive adhesive layer A is on the side of the polarizing element that does not have the transparent protective film. It is provided,
The pressure-sensitive adhesive layer A moisture permeability is at ^{65 g / (m 2 · 24h} ) or less state, and are thick 30μm or less,
The pressure-sensitive adhesive layer A is a pressure-sensitive adhesive layer containing a rubber-based polymer as a main component.
A polarizing film with an adhesive layer, wherein the rubber-based polymer is one or more rubber-based polymers selected from the group consisting of styrene-based thermoplastic elastomers, polyisobutylene, and butyl rubber. The polarizing film with an adhesive layer according to claim 1 , wherein the pressure-sensitive adhesive layer A further contains a pressure-imparting resin. The polarizing film with a pressure-sensitive adhesive layer according to claim 1 or 2 , wherein the pressure-sensitive adhesive layer A is a light-diffusing pressure-sensitive adhesive layer A1 containing light-diffusing fine particles. The polarizing film with an adhesive layer according to claim 3 , wherein the haze of the light diffusing adhesive layer A1 is 10 to 95%. The polarizing film with an adhesive layer according to claim 3 or 4 , 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 3 to 5 , wherein the light diffusing fine particles have a volume average particle size of 1 to 4 μm. An optical member comprising the polarizing film with an adhesive layer according to any one of claims 1 to 6 and a brightness improving film provided on the adhesive layer side of the polarizing film with an adhesive layer. The optical member according to claim 7 , wherein a prism sheet is further provided on the side of the brightness improving film that does not have a polarizing film with an adhesive layer. An image display device comprising the polarizing film with an adhesive layer according to claims 1 to 6 and one or more selected from the group consisting of the optical members according to claims 7 and 8.

Images