JP2023121228A - Protective film, polarizing plate, method of manufacturing polarizing plate, and method of manufacturing image display device - Google Patents

Abstract

To suppress deformation of polarizing plates.SOLUTION: A protective film according to an embodiment of the present invention comprises a base material film having opposing first and second principal surfaces and an adhesive layer provided on a side of the first principal surface of the base material film, and features a peeling force of 0.03 N/25 mm or greater against an adherend having a water contact angle of 90° or greater, and an in-plane sheer force of 35 N/100 mm2 or less against the adherend.SELECTED DRAWING: Figure 1C

Description

The present invention relates to a protective film, a polarizing plate, a method for producing a polarizing plate, and a method for producing an image display device.

Image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (eg, organic EL display devices and inorganic EL display devices) are rapidly spreading. A polarizing plate is generally used for an image display panel mounted in an image display device. Typically, a polarizing plate with a retardation layer, in which a polarizing plate and a retardation plate are integrated, is widely used (for example, Patent Document 1).

The polarizing plate is typically obtained by laminating a polarizer having a polarizing function and a member for protecting it. Further, the image display panel is typically obtained by bonding a polarizing plate to the image display panel main body.

Japanese Patent No. 3325560

In the manufacturing process of the polarizing plate and the image display device, the polarizing plate may be deformed due to handling and the appearance may be impaired. For example, the polarizing plate may have a mark due to handling.

In view of the above, a main object of the present invention is to suppress deformation of the polarizing plate during the manufacturing process.

According to embodiments of the present invention, protective films are provided. This protective film has a base film having a first main surface and a second main surface facing each other, and a pressure-sensitive adhesive layer disposed on the first main surface side of the base film. The peel force for an adherend having an angle of 90° or more is 0.03 N/25 mm or more, and the in-plane shearing force for the adherend is 35 N/100 mm ² or less.
In one embodiment, the pressure-sensitive adhesive layer has a thickness greater than 10 μm.
In one embodiment, the pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive, the acrylic pressure-sensitive adhesive contains a (meth)acrylic polymer having a polar functional group, and a monomer forming the (meth)acrylic polymer The content of the monomer component having a polar functional group is 2 parts by weight or more with respect to 100 parts by weight.
According to another embodiment of the invention, a polarizer is provided. The polarizing plate includes the above protective film, a laminated film having a substrate and a surface treatment layer having a water contact angle of 90° or more, and a polarizer, and the protective film is attached to the surface treatment layer. be matched.
According to yet another embodiment of the present invention, a method for manufacturing a polarizing plate is provided. This method for producing a polarizing plate includes laminating the protective film to the surface-treated layer of a laminated film having a substrate and a surface-treated layer having a water contact angle of 90° or more, and Laminating a polarizer on the material side.
According to yet another embodiment of the invention, a method for manufacturing an image display device is provided. The method for manufacturing the image display device includes laminating the polarizing plate obtained by the above manufacturing method on the main body of the image display panel.

According to the embodiments of the present invention, deformation of the polarizing plate can be suppressed.

It is a figure which shows the manufacturing process 1 of the polarizing plate which concerns on one Embodiment of this invention. It is a figure which shows the process 2 following the said process 1. FIG. It is a figure which shows the process 3 following the said process 2. FIG. It is a schematic sectional drawing which shows the modification of a polarizing plate. 1 is a schematic cross-sectional view showing an outline of a state in which a polarizing plate is arranged on an organic EL panel in an organic EL display device according to one embodiment of the present invention; FIG. It is a figure for demonstrating the measuring method of a shear force. It is a figure for demonstrating the evaluation method of deformation|transformation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In addition, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the embodiment, but this is only an example and limits the interpretation of the present invention. not something to do.

(Definition of terms and symbols)
Definitions of terms and symbols used herein are as follows.
(1) refractive index (nx, ny, nz)
"nx" is the refractive index in the direction in which the in-plane refractive index is maximum (i.e., slow axis direction), and "ny" is the in-plane direction orthogonal to the slow axis (i.e., fast axis direction) and "nz" is the refractive index in the thickness direction.
(2) In-plane retardation (Re)
“Re(λ)” is an in-plane retardation measured at 23° C. with light having a wavelength of λ nm. For example, "Re(550)" is the in-plane retardation measured with light having a wavelength of 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ)=(nx−ny)×d, where d (nm) is the thickness of the layer (film).
(3) Thickness direction retardation (Rth)
“Rth(λ)” is the retardation in the thickness direction measured at 23° C. with light having a wavelength of λ nm. For example, “Rth(550)” is the retardation in the thickness direction measured at 23° C. with light having a wavelength of 550 nm. Rth(λ) is determined by the formula: Rth(λ)=(nx−nz)×d, where d (nm) is the thickness of the layer (film).
(4) Nz Coefficient The Nz coefficient is obtained by Nz=Rth/Re.

A method for producing a polarizing plate according to one embodiment of the present invention includes laminating a protective film to a surface treatment layer of a laminated film having a substrate and a surface treatment layer, and attaching a polarizer to the substrate side of the laminated film. laminating.

1A to 1C are diagrams illustrating the manufacturing process of a polarizing plate according to one embodiment of the present invention.

In FIG. 1A showing step 1, the polarizer 30 is laminated on the substrate 21 side of the laminated film 20 having the substrate 21 and the surface treatment layer 22, the protective layer 40 is laminated on the polarizer 30, and the laminate 90 is Shows the completed state. The laminate 90 has the laminated film 20, the polarizer 30, and the protective layer 40 in this order. The base material 21 of the laminated film 20 can function as a protective layer for the polarizer 30 . The protective layer 40 may function as a retardation layer (for example, a λ/4 plate). The laminate 90 is typically elongated and can be wound into a roll. Here, the term "elongated" refers to an elongated shape whose length is sufficiently longer than its width, for example, an elongated shape whose length is 10 times or more, preferably 20 times or more, its width.

FIG. 1B showing step 2 shows a state in which the adhesive layer 50 is formed on the protective layer 40 side of the laminate 90 and the polarizing plate 100 is completed. Although not shown, a release liner is practically adhered to the surface of the pressure-sensitive adhesive layer 50 . By using a release liner, for example, it is possible to protect the pressure-sensitive adhesive layer 50 and roll-form the polarizing plate.

FIG. 1C showing step 3 shows a state in which the protective film 10 is attached to the surface treatment layer 22 of the laminate film 20 of the polarizing plate 100 . Hereinafter, the state in which the protective film (10) is adhered may be referred to as a protective film-attached polarizing plate (110).

The protective film 10 includes a base film 11 having a first main surface 11a and a second main surface 11b facing each other, an adhesive layer 12 disposed on the side of the first main surface 11a of the base film 11, and a base material. It has a treatment layer 13 arranged on the second main surface 11 b side of the film 11 . The bonding of the protective film 10 to the laminated film 20 is performed, for example, while conveying them in rolls (so-called roll-to-roll).

The protective film 10 is detachably attached to the laminated film 20 . The protective film 10 is applied until the polarizing plate obtained by the embodiment of the present invention is used (for example, until it is laminated on the image display panel main body), or in the manufacturing process of the final product (image display device). It may be peeled off or mounted as it is on the final product.

The lamination order of the members constituting the polarizing plate (polarizing plate with protective film) is not particularly limited. For example, in the illustrated example, after the laminated film 20 and the polarizer 30 are laminated, the protective film 10 is attached to the laminated film 20. However, after the protective film 10 is attached to the laminated film 20, the laminated film 20 and the polarizer The child 30 may be laminated.

In the illustrated example, polarizing plate 100 has protective layer 40 and adhesive layer 50 in addition to laminated film 20 and polarizer 30, but polarizing plate 100 has at least laminated film 20 and polarizer 30. It is good if there is On the other hand, although not shown, the polarizing plate 100 may have other members. In the example shown in FIG. 2, the polarizing plate 100 (protective film-attached polarizing plate 110) further includes a retardation layer (e.g., λ/4 plate) 60 and an adhesive layer 52 in addition to the configuration shown in FIG. 1C. ing. Although not shown, a release liner is practically adhered to the surface of the pressure-sensitive adhesive layer 52 .

Each of the above members can be laminated via any appropriate adhesive layer. Specific examples of the adhesive layer include an adhesive layer and an adhesive layer. For example, the polarizer and the protective layer are attached via an adhesive layer. Specifically, the polarizer and the protective layer are bonded using an active energy ray-curable adhesive. The thickness of the active energy ray-curable adhesive after curing (thickness of the adhesive layer) is, for example, 0.2 μm to 3.0 μm, preferably 0.4 μm to 2.0 μm, more preferably 0.6 μm. ˜1.5 μm.

[Polarizer]
The polarizer is typically a resin film containing a dichroic substance (eg, iodine). Examples of resin films include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene/vinyl acetate copolymer films.

The thickness of the polarizer is preferably 18 μm or less, more preferably 15 μm or less, and even more preferably 12 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 42.0% to 46.0%, more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or higher, more preferably 99.0% or higher, still more preferably 99.9% or higher.

A polarizer can be made by any suitable method. Specifically, the polarizer may be produced from a single-layer resin film, or may be produced using a laminate of two or more layers.

The method of producing a polarizer from the single-layer resin film typically includes subjecting the resin film to a dyeing treatment with a dichroic substance such as iodine or a dichroic dye and a stretching treatment. As the resin film, for example, hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene/vinyl acetate copolymer films are used. The method may further include an insolubilization treatment, a swelling treatment, a cross-linking treatment, and the like. Since such a manufacturing method is well known and commonly used in the industry, detailed description thereof will be omitted.

A polarizer obtained using the laminate can be produced, for example, using a laminate of a resin substrate and a resin film or resin layer (typically, a PVA-based resin layer). Specifically, a PVA-based resin solution is applied to a resin base material, dried to form a PVA-based resin layer on the resin base material, and a laminate of the resin base material and the PVA-based resin layer is obtained; stretching and dyeing the laminate to make the PVA-based resin layer a polarizer; In this embodiment, preferably, a PVA-based resin layer containing a halide and a PVA-based resin is formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Furthermore, stretching may further include stretching the laminate in air at a high temperature (eg, 95° C. or higher) before stretching in an aqueous boric acid solution, if necessary. In addition, in the present embodiment, the laminate is preferably subjected to drying shrinkage treatment for shrinking the laminate by 2% or more in the width direction by heating while conveying in the longitudinal direction. Typically, the manufacturing method of the present embodiment includes subjecting the laminate to an in-air auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment in this order. By introducing auxiliary stretching, it is possible to improve the crystallinity of PVA and achieve high optical properties even when PVA is applied onto a thermoplastic resin. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as deterioration of orientation and dissolution of PVA when immersed in water in the subsequent dyeing process or stretching process, resulting in high optical properties. can be achieved. Furthermore, when the PVA-based resin layer is immersed in a liquid, compared with the case where the PVA-based resin layer does not contain a halide, the disturbance of the orientation of the PVA molecules and the deterioration of the orientation can be suppressed, and high optical properties can be obtained. achievable. Furthermore, high optical properties can be achieved by shrinking the laminate in the width direction by drying shrinkage treatment. A polarizing plate can be obtained by laminating a protective layer on the peeled surface of the obtained resin substrate/polarizer laminate, or on the surface opposite to the peeled surface. Details of the method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580 and Japanese Patent No. 6470455. These publications are incorporated herein by reference in their entireties.

[Protective layer]
The protective layer may be formed of any appropriate film that can be used as a protective layer for polarizers. Specific examples of the material that is the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, polysulfones, Examples include resins such as polystyrene, cycloolefins such as polynorbornene, polyolefins, (meth)acrylic, and acetate.

The thickness of the protective layer is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, still more preferably 15 μm to 35 μm.

The protective layer 40 arranged on the side of the polarizer 30 on which the laminated film 20 is not arranged is preferably optically isotropic in one embodiment. As used herein, “optically isotropic” means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is −10 nm to +10 nm. say.

[Laminated film]
The laminated film has a substrate and a surface treatment layer formed on the substrate. The substrate may function as a protective layer for the polarizer, the details of which are described above. The polarizing plate obtained by the embodiment of the present invention is typically arranged on the viewing side of the image display device, and the laminated film is arranged on the viewing side. In one embodiment, the surface treatment layer of the laminated film is located on the outermost surface of the image display device. Therefore, the base material (protective layer on the viewing side) is provided with a surface treatment layer such as hard coat (HC) treatment, antireflection treatment, antisticking treatment, antiglare treatment, antifouling treatment, etc. is preferred.

In one embodiment, the surface treatment layer has an antiglare function and an antireflection function. Specifically, the surface treatment layer has an antiglare layer and an antireflection layer in this order from the substrate side. An antiglare layer typically contains a resin and a filler. Specifically, the antiglare property can be obtained by incorporating a filler into the resin to form fine irregularities on the surface of the resulting layer (antiglare layer). By providing the antiglare layer, for example, on the surface of the image display device, it is possible to scatter external light such as a fluorescent lamp and sunlight, suppress reflection of an image, and prevent a decrease in contrast. The antireflection layer can reduce reflection on the surface of the antiglare layer. The reflectance of the surface treatment layer side of the laminated film is preferably 3% or less, more preferably 1% or less.

The antireflection layer can be obtained, for example, by coating the antireflection layer-forming coating liquid on the antiglare layer and drying and curing a coating film. The antireflection layer-forming coating liquid may contain, for example, a resin component (curable compound), a fluorine-containing additive, hollow particles, solid particles, a solvent, and the like, and may be obtained, for example, by mixing these. can be done.

Examples of the curing mechanism of the resin component (curable compound) contained in the antireflection layer-forming coating liquid include thermosetting and photocuring. As the resin component, for example, a curable compound having at least one of an acrylate group and a methacrylate group is used, and examples thereof include silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, and spiroacetal resins. , polybutadiene resins, polythiol polyene resins, and oligomers or prepolymers such as acrylates and methacrylates of polyfunctional compounds such as polyhydric alcohols. These may be used individually by 1 type, and may use 2 or more types together.

For the resin component, for example, a reactive diluent having at least one of an acrylate group and a methacrylate group can also be used. Reactive diluents that can be used include, for example, reactive diluents described in JP-A-2008-88309, and include monofunctional acrylates, monofunctional methacrylates, polyfunctional acrylates, polyfunctional methacrylates, and the like. As the reactive diluent, tri- or more functional acrylates and tri- or more functional methacrylates are preferably used from the viewpoint of obtaining excellent hardness. Reactive diluents also include, for example, butanediol glycerol ether diacrylate, acrylates of isocyanuric acid, methacrylates of isocyanuric acid, and the like. These may be used individually by 1 type, and may use 2 or more types together. A curing agent, for example, may be used to cure the resin component. As the curing agent, for example, a known polymerization initiator (eg, thermal polymerization initiator, photopolymerization initiator, etc.) can be used.

The fluorine-containing additive may be, for example, a fluorine-containing organic compound or a fluorine-containing inorganic compound. Examples of organic compounds containing fluorine include fluorine-containing antifouling coating agents, fluorine-containing acrylic compounds, and fluorine/silicon-containing acrylic compounds. A commercial item can be used as an organic compound containing fluorine. Specific examples of commercially available products include "KY-1203" (trade name) manufactured by Shin-Etsu Chemical Co., Ltd., "Megafac" (trade name) manufactured by DIC Corporation, and the like. The content of the fluorine-containing additive is, for example, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.15 parts by weight or more, 0.20 parts by weight or more, or 0 parts by weight with respect to 100 parts by weight of the resin component. .25 parts by weight or more, 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 3 parts by weight or less.

Examples of the hollow particles include silica particles, acrylic particles, and acrylic-styrene copolymer particles. As the hollow silica particles, commercially available products (for example, trade names “Sururia 5320” and “Sururia 4320” manufactured by Nikki Shokubai & Chemicals Co., Ltd.) can be used. The weight average particle diameter of the hollow particles may be, for example, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, or 70 nm or more, and may be 150 nm or less, 140 nm or less, 130 nm or less, 120 nm or less, or 110 nm or less. good too. Although the shape of the hollow particles is not particularly limited, it is preferably approximately spherical. Specifically, the aspect ratio of the hollow particles is preferably 1.5 or less. The content of the hollow particles may be, for example, 30 parts by weight or more, 50 parts by weight or more, 70 parts by weight or more, 90 parts by weight or more, or 100 parts by weight or more with respect to 100 parts by weight of the resin component. It may be no more than 270 parts by weight, no more than 250 parts by weight, no more than 200 parts by weight, or no more than 180 parts by weight.

Examples of the solid particles include silica particles, zirconia particles, and titania particles. As the solid silica particles, commercially available products (for example, product names “MEK-2140Z-AC”, “MIBK-ST”, “IPA-ST” manufactured by Nissan Chemical Industries, Ltd.) can be used. The weight average particle diameter of the solid particles may be, for example, 5 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, or 25 nm or more, and may be 330 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, or 100 nm or less. may Although the shape of the hollow particles is not particularly limited, it is preferably approximately spherical. Specifically, the aspect ratio of the hollow particles is preferably 1.5 or less. The content of the solid particles may be, for example, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, or 25 parts by weight or more with respect to 100 parts by weight of the resin component. It may be 150 parts by weight or less, 120 parts by weight or less, 100 parts by weight or less, or 80 parts by weight or less.

Any appropriate solvent can be used as the solvent. Examples of solvents include alcohols such as methanol, ethanol, isopropyl alcohol, butanol, TBA (tertiary butyl alcohol), and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, MIBK (methyl isobutyl ketone), and cyclopentanone. esters such as methyl acetate, ethyl acetate, butyl acetate, and PMA (propylene glycol monomethyl ether acetate); ethers such as diisopropyl ether and propylene glycol monomethyl ether; glycols such as ethylene glycol and propylene glycol; ethyl cellosolve, butyl cellosolve, etc. Aliphatic hydrocarbons such as hexane, heptane and octane; Aromatic hydrocarbons such as benzene, toluene and xylene. These may be used individually by 1 type, and may use 2 or more types together. The content of the solvent is such that the weight of the solid content relative to the total weight of the antireflection layer-forming coating solution is, for example, 0.1% by weight or more, 0.3% by weight or more, 0.5% by weight or more, 1.0% by weight or more, or 1.5% by weight or more, and 20% by weight or less, 15% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less. can be

Examples of the coating method for the antireflection layer-forming coating solution include known coating methods such as fountain coating, die coating, spin coating, spray coating, gravure coating, roll coating, and bar coating. method can be used. The drying temperature of the coating film is, for example, 30° C. to 200° C., and the drying time is, for example, 30 seconds to 90 seconds. Curing of the coating film can be performed by, for example, heating or light irradiation (typically, ultraviolet irradiation). A high-pressure mercury lamp, for example, is used as a light source for light irradiation. The amount of ultraviolet irradiation is preferably 50 mJ/cm ² to 500 mJ/cm ² as an integrated exposure amount at an ultraviolet wavelength of 365 nm.

Preferably, the surface treatment layer may have antifouling properties. Specifically, the surface treatment layer may contain at least one of fluorine and silicon. On the other hand, such a surface treatment layer can reduce adhesion to the protective film.

The thickness of the surface treatment layer is, for example, 1 μm to 20 μm, preferably 2 μm to 15 μm, more preferably 3 μm to 10 μm.

The surface treatment layer (laminated film) has a water contact angle of 90° or more, preferably 93° or more. On the other hand, the water contact angle of the surface of the surface treatment layer (laminated film) is, for example, 125° or less.

[Retardation layer]
The retardation layer may be a single layer or may have a laminated structure (for example, a two-layer structure). The retardation layer can be composed of any suitable material. Specifically, the retardation layer may be a resin film (a stretched film of a resin film), an oriented and solidified layer of a liquid crystal compound, or a combination thereof. A resin film typically contains a resin containing at least one bonding group selected from the group consisting of carbonate bonds and ester bonds. In other words, the resin film contains a polycarbonate-based resin, a polyester-based resin, or a polyester carbonate-based resin.

The retardation layer may have any appropriate optical properties depending on the application. In one embodiment, the retardation layer includes a first retardation layer that can function as a λ/4 plate. The first retardation layer typically exhibits a refractive index characteristic of nx>ny=nz. The in-plane retardation Re(550) of the retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, still more preferably 120 nm to 160 nm. Here, "ny=nz" includes not only the case where ny and nz are completely equal but also the case where they are substantially equal. Therefore, ny>nz or ny<nz may be satisfied within a range that does not impair the effects of the present invention.

The Nz coefficient of the first retardation layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. The first retardation layer may exhibit reverse dispersion wavelength characteristics in which the retardation value increases according to the wavelength of the measurement light. In this case, Re(450)/Re(550) of the retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and 0.95 or less.

When the first retardation layer is composed of a resin film, its thickness is preferably 10 μm or more and 70 μm or less, more preferably 20 μm or more and 60 μm or less.

[Protective film]
The protective film has a base film having a first main surface and a second main surface facing each other, and an adhesive layer arranged on the first main surface side of the base film.

A base film that constitutes the protective film is made of any appropriate resin. Materials for forming the base film include, for example, ester-based resins such as polyethylene terephthalate (PET)-based resins, cycloolefin-based resins such as norbornene-based resins, olefin-based resins such as polypropylene, polyamide-based resins, and polycarbonate-based resins. and a copolymer resin of Preferably, an ester-based resin (for example, polyethylene terephthalate-based resin) is used.

The thickness of the base film is preferably 10 μm to 150 μm, more preferably 20 μm to 100 μm, still more preferably 30 μm to 50 μm.

The protective film has a peeling force of 0.03 N/25 mm or more from an adherend having a water contact angle of 90° or more. Satisfying such a peeling force can prevent the protective film from lifting or peeling off from the adherend in the manufacturing process of the polarizing plate and the image display device, and can contribute to the improvement of the yield. On the other hand, the peel strength of the protective film to an adherend having a water contact angle of 90° or more is, for example, 0.09 N/25 mm or less, and may be 0.08 N/25 mm or less.

Typically, the adherend is a polarizing plate. Specifically, it is the laminated film (surface treatment layer of the laminated film).

The in-plane shear force of the protective film on the adherend is 35 N/100 mm ² or less, preferably 30 N/100 mm ² or less. Satisfying such a shear force can suppress deformation of the polarizing plate due to handling in the manufacturing process of the polarizing plate and the image display device. Specifically, when an external force is locally applied to the polarizing plate from the protective film side, the binding force due to the displacement of the shear direction that can occur at the interface between the protective film and the adherend (polarizing plate) is weakened. and can suppress deformation (for example, impressions). Alternatively, the deformation once occurred may revert. On the other hand, the in-plane shear force of the protective film on the adherend is, for example, 10 N/100 mm ² or more, and may be 15 N/100 mm ² or more.

The thickness of the pressure-sensitive adhesive layer constituting the protective film is, for example, more than 10 μm, preferably 13 μm or more. On the other hand, the thickness of the adhesive layer constituting the protective film is, for example, 30 μm or less, preferably 27 μm or less. In one embodiment, the shear force is controlled by adjusting the thickness of the adhesive layer. For example, by adjusting the thickness of the pressure-sensitive adhesive layer, it is possible to satisfy the above shear force while ensuring adhesion to an adherend having a water contact angle of 90° or more.

The pressure-sensitive adhesive layer that constitutes the protective film typically contains an acrylic pressure-sensitive adhesive. The acrylic pressure-sensitive adhesive preferably contains a (meth)acrylic polymer having a polar functional group. A (meth)acrylic polymer having a polar functional group is typically a polymer of a monomer having a polar functional group and an alkyl (meth)acrylate. (Meth)acrylate refers to acrylate and/or methacrylate.

Examples of the monomer having a polar functional group include carboxyl group-containing monomers and hydroxyl group-containing monomers. These may be used alone or in combination. Carboxyl group-containing monomers are preferably used.

The carboxyl group-containing monomer is a compound having a carboxyl group and a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group. Specific examples of carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Among these, acrylic acid is preferably used.

The content of the monomer component having a polar functional group in the (meth)acrylic polymer having a polar functional group is preferably 2 parts by weight or more with respect to 100 parts by weight of the monomer forming the (meth)acrylic polymer. , more preferably 2.5 parts by weight or more. With such a polymer, it is possible to satisfactorily achieve the above peel strength. On the other hand, the content of the monomer component having a polar functional group is, for example, 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 100 parts by weight of the monomer forming the (meth)acrylic polymer. 3 parts by weight or less. Such a polymer can satisfactorily achieve the above shear force.

The alkyl group contained in the above alkyl (meth)acrylate includes, for example, a linear or branched alkyl group having 1 to 18 carbon atoms. Specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, and decyl. group, isodecyl group, dodecyl group, isomyristyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group and octadecyl group. These may be used alone or in combination. The average carbon number of the alkyl group is preferably 3-10. Among them, a 2-ethylhexyl group is preferred.

The content of the alkyl (meth)acrylate in the (meth)acrylic polymer having a polar functional group is, for example, 10 parts by weight to 90 parts by weight with respect to 100 parts by weight of the monomer forming the (meth)acrylic polymer, It is preferably 20 to 80 parts by weight, more preferably 30 to 70 parts by weight.

In one embodiment, the (meth)acrylic polymer contains structural units derived from other copolymerized monomers. Other copolymerizable monomers include, for example, vinyl esters such as vinyl acetate and vinyl propionate. These may be used alone or in combination. Vinyl acetate is preferably used.

The content of the other copolymerizable monomer in the (meth)acrylic polymer having a polar functional group is, for example, 5 parts by weight or more and 60 parts by weight or less with respect to 100 parts by weight of the monomer forming the (meth)acrylic polymer. , preferably 15 to 55 parts by weight, more preferably 25 to 50 parts by weight.

The (meth)acrylic polymer having a polar functional group has a weight average molecular weight Mw of, for example, 30×10 ⁴ to 60×10 ⁴ , preferably 40×10 ⁴ to 50×10 ⁴ .

The glass transition temperature (Tg) of the (meth)acrylic polymer having a polar functional group is preferably −15° C. or lower, more preferably −20° C. or lower, and still more preferably −25° C. or lower. Such a polymer can satisfactorily achieve the above shear force. On the other hand, the Tg of the (meth)acrylic polymer having a functional group is, for example, −70° C. or higher, may be −60° C. or higher, or may be −50° C. or higher.

The above Tg (unit: K) can be obtained from Fox's formula: 1/Tg=Σ(Wi/Tgi). In the Fox formula, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of the monomer i in the copolymer (copolymerization ratio based on weight), and Tgi is the glass of the homopolymer of the monomer i. It represents the transition temperature (unit: K). As the glass transition temperature of the homopolymer, values described in known materials can be adopted.

The glass transition temperatures of homopolymers of representative monomers are as follows.
2-ethylhexyl acrylate: -70°C
Vinyl acetate: 32°C
Acrylic acid: 106°C
2-hydroxyethyl acrylate: 15°C
4-hydroxybutyl acrylate: -40°C

The acrylic pressure-sensitive adhesive may contain a cross-linking agent. Typically, the cross-linking agent is contained in the acrylic pressure-sensitive adhesive in the form after the cross-linking reaction in the resulting pressure-sensitive adhesive layer. By containing a cross-linking agent, for example, an appropriate cohesive force can be imparted to the acrylic pressure-sensitive adhesive. Examples of cross-linking agents include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, silicone-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, silane-based cross-linking agents, alkyl-etherified melamine-based cross-linking agents, and metal chelate-based cross-linking agents. , peroxides, and polyfunctional monomers. These may be used alone or in combination.

The amount of the cross-linking agent is, for example, 0.1 to 10 parts by weight, preferably 1 to 8 parts by weight, per 100 parts by weight of the (meth)acrylic polymer having a polar functional group.

The acrylic pressure-sensitive adhesive may contain any appropriate additive. Additives include, for example, leveling agents, cross-linking aids, tackifiers, plasticizers, pigments, dyes, fillers, antioxidants, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, and release modifiers. , softeners, surfactants, flame retardants, and antioxidants. In one embodiment, the acrylic adhesive is substantially free of additives. Specifically, the content of the additive is preferably 0.01 parts by weight or less, more preferably 0.001 parts by weight, with respect to 100 parts by weight of the (meth)acrylic polymer having a polar functional group. It is below. For example, by controlling the type and content of the monomer that forms the (meth)acrylic polymer to control the release force, it is possible to reduce the use of additives and prevent the adhesion of dirt to the adherend (polarizing plate). can do.

The surface resistance value of the protective film (the surface resistance value of the surface on the second main surface side of the base film) is preferably 1.0×10 ⁸ Ω/□ or more, more preferably 1.0×10 ⁹ Ω/□ or more. Such a surface resistance value can be satisfactorily achieved by providing a treatment layer on the second main surface side of the base film, as shown in FIG. 1C. On the other hand, the surface resistance value of the protective film is, for example, 1.0×10 ¹³ Ω/□ or less, preferably 1.0×10 ¹² Ω/□ or less, more preferably 1.0×10 ¹¹ Ω/ □ is less than or equal to.

The treatment layer typically contains an antistatic agent. Specifically, the treatment layer can be formed by applying a coating liquid containing an antistatic agent and a solvent (for example, an organic solvent or an aqueous solvent such as water) to the substrate film and drying the coating liquid. Antistatic agents include, for example, quaternary ammonium cation-containing polymers, polyaniline sulfonic acid-based antistatic agents, and the like, and quaternary ammonium cation-containing polymers are preferably used.

The quaternary ammonium cation contained in the quaternary ammonium cation-containing polymer includes, for example, trimethylammonium cation, triethylammonium cation, tripropylammonium cation, methyldiethylammonium cation, ethyldimethylammonium cation, methyldipropylammonium cation, dimethyl Examples include benzylammonium cation, diethylbenzylammonium cation, methyldibenzylammonium cation, and ethyldibenzylammonium cation. Among these, trimethylammonium cation is preferably used.

A method for manufacturing an image display device according to one embodiment of the present invention includes bonding the polarizing plate (polarizing plate with a protective film) to an image display panel main body. An organic EL display device will be described below as an example of an image display device.

FIG. 3 is a schematic cross-sectional view showing an outline of a state in which polarizing plates are arranged on an organic EL panel in an organic EL display device according to one embodiment of the present invention. The organic EL panel 200 includes an organic EL panel main body 70 and a polarizing plate 110 with a protective film. The protective film-equipped polarizing plate 110 is arranged so that the polarizer 30 is closer to the organic EL panel main body 70 than the laminated film 20 is. Specifically, the polarizing plate 100 is attached to the organic EL panel main body 70 with the adhesive layer 52 .

The organic EL panel main body 70 has a substrate 71 and an upper structure layer 72 including a circuit layer including thin film transistors (TFTs) and the like, an organic light emitting diode (OLED), a sealing film for sealing the OLED, and the like. For example, when a flexible substrate (for example, a resin substrate) is used as the substrate 71, the resulting organic EL display device can be curved, bent, bent, rolled up, and the like.

Although not shown, when used as an image display device for mobile devices, the organic EL panel main body 70 may typically include a touch panel. The protective film 10, which can be positioned on the outermost surface of the organic EL panel 200, satisfies the surface resistance value (1.0×10 ⁸ Ω/□ or more), thereby preventing touch panel sensor errors in the manufacturing process of the organic EL display device. can be suppressed to improve production efficiency. Here, the touch panel sensor error means that when checking the operability of the touch panel in the manufacturing process (for example, inspection process) of the image display panel (image display device), the screen does not respond even if the screen is touched with a finger. It is a phenomenon that makes it difficult to

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples. The thickness, water contact angle and surface resistance are values measured by the following measuring methods. Also, unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are by weight.
1. Thickness The thickness of 10 μm or less was measured using a scanning electron microscope (manufactured by JEOL Ltd., product name “JSM-7100F”). A thickness exceeding 10 μm was measured using a digital micrometer (manufactured by Anritsu Co., Ltd., product name “KC-351C”).
2. Water contact angle The water contact angle on the surface treatment layer side of the laminated film was measured. Specifically, in an environment of 23 ° C. and 50% RH, a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., trade name “DMo-501 type”, control box “DMC-2”, control / analysis software “FAMAS ( Version 5.0.30)”) was used to measure by the sessile drop method. The amount of distilled water dropped was 2 μL, and the contact angle was calculated by the θ/2 method from the image 5 seconds after the drop.
3. Surface Resistance Value The surface resistance value was measured by an eddy current method using a non-contact surface resistance meter trade name “EC-80” manufactured by Napson Co., Ltd. The measurement temperature was 23°C.

[Example 1]
(Production of polarizer)
A long roll of polyvinyl alcohol (PVA)-based resin film with a thickness of 30 μm (trade name “PE3000” manufactured by Kuraray Co., Ltd.) was simultaneously stretched uniaxially in the longitudinal direction by a roll stretching machine so as to be 5.9 times the length. A polarizer having a thickness of 12 μm was produced by performing swelling, dyeing, cross-linking, and washing treatments in this order, and finally performing a drying treatment.
In the swelling treatment, the film was stretched 2.2 times while being treated with pure water at 20°C. Next, the dyeing treatment is performed in an aqueous solution at 30° C. in which the weight ratio of iodine and potassium iodide is 1:7 and the iodine concentration is adjusted so that the single transmittance of the resulting polarizer is 45.0%. while stretching to 1.4 times. Then, the cross-linking treatment employed two-step cross-linking treatment, and the first-step cross-linking treatment was performed by stretching the film 1.2 times while treating it in an aqueous solution of boric acid and potassium iodide at 40°C. The boric acid content of the aqueous solution for the first-stage cross-linking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight. In the second-stage cross-linking treatment, the film was stretched 1.6 times while being treated in an aqueous solution of boric acid and potassium iodide at 65°C. The boric acid content of the aqueous solution for the second-stage cross-linking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight. Then, the washing treatment was carried out with an aqueous potassium iodide solution at 20°C. The potassium iodide content of the aqueous solution for the cleaning treatment was 2.6% by weight. Finally, a drying treatment was performed at 70° C. for 5 minutes to obtain a polarizer.

(Production of laminate)
A TAC film (thickness: 25 μm, Fuji Film Co., Ltd., trade name “TJ25UL”) was attached to one side of the obtained polarizer via an ultraviolet curable adhesive, and the other side of the polarizer was bonded to the other side of the polarizer via an ultraviolet curable adhesive. A TAC film (laminated film, thickness 32 μm) having a surface treatment layer formed thereon was laminated to obtain a laminate. The TAC film on which the surface treatment layer is formed has a surface treatment layer (thickness: 7 μm, water contact angle: 93.3°) formed on the TAC film (thickness: 25 μm, Fuji Film Co., Ltd., trade name “TJ25UL”). The surface treatment layer was formed by the procedure shown below.

<Surface treatment layer>
1. Formation of antiglare layer UV-curable urethane acrylate resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “UV1700TL”, solid content 80%) 50 parts by weight, and polyfunctional containing pentaerythritol triacrylate as the main component A mixture of 50 parts by weight of acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solid content 100%) was prepared. Crosslinked polymethyl methacrylate particles (manufactured by Sekisui Plastics Co., Ltd., trade name "Techpolymer", weight average particle size: 3 µm, refractive index: 1.525) are added to 4 parts by weight of the resin solid content of the mixture. Parts by weight, 1.5 parts by weight of synthetic smectite (manufactured by Co-op Chemical Co., Ltd., trade name "LUCENTITE SAN"), which is an organic clay (thixotropy-imparting agent), and a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907"). ”) was mixed with 0.15 parts by weight of a leveling agent (manufactured by Kyoeisha Chemical Co., Ltd., trade name “LE303”, solid content 40%). Here, the organic clay was used after being diluted with toluene so that the solid content was 6%.
The obtained mixture was diluted with a toluene/ethyl acetate/cyclopentanone (CPN) mixed solvent (weight ratio 35/41/24) so that the solid content concentration was 40% by weight, to obtain an antiglare layer-forming material. (Coating liquid) was prepared.

The obtained material for forming an antiglare layer (coating liquid) was applied onto a TAC film (thickness: 25 μm, product name: “TJ25UL”, manufactured by FUJIFILM Corporation). After that, the coating film was irradiated with ultraviolet rays with a wavelength of 365 nm using a high-pressure mercury lamp so that the integrated light amount was 300 mJ/cm ² , and further dried by heating at 80 ° C. for 60 seconds to form an antiglare layer with a thickness of 7 µm. formed.

2. Formation of antireflection layer Polyfunctional acrylate mainly composed of pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name “Viscoat # 300”, solid content 100% by weight) 100 parts by weight, hollow nanosilica particles (JGC Catalysts and Chemicals Co., Ltd., trade name "Sururia 5320", solid content 20% by weight, weight average particle diameter 75 nm) 100 parts by weight, solid nanosilica particles (manufactured by Nissan Chemical Industries, Ltd., trade name "MEK-2140Z-AC ”, solid content 30% by weight, weight average particle diameter 10 nm), fluorine-containing additive (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KY-1203”, solid content 20% by weight) 12 parts by weight, and a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907", solid content 100% by weight) was mixed with 3 parts by weight. To this mixture, a mixed solvent of TBA, MIBK and PMA at a weight ratio of 60:25:15 was added as a solvent so that the total solid content was 4% by weight. A working solution was prepared.

The obtained antireflection layer-forming coating liquid was applied onto the antiglare layer with a wire bar. The applied coating liquid was heated at 80° C. for 1 minute and dried to form a coating film. The obtained coating film was subjected to curing treatment by irradiating ultraviolet light with an accumulated light quantity of 300 mJ/cm ² with a high-pressure mercury lamp to form an antireflection layer having a thickness of 0.1 μm.
Thus, a surface treatment layer was formed.

(Production of laminate I)
An acrylic pressure-sensitive adhesive layer (thickness: 12 μm) was formed on the TAC film side of the obtained laminate, and a release liner was attached to the formed pressure-sensitive adhesive layer surface. Next, a protective film was attached to the laminate film side of the obtained laminate to obtain a laminate I. The protective film used was produced by the procedure shown below.

<Protective film>
A PET film having an antistatic layer containing a quaternary ammonium cation-containing polymer on one side (thickness 38 μm, manufactured by Mitsubishi Chemical, trade name "DIAFOIL T100M38") was coated on the side without an antistatic layer with the following adhesive. The adhesive composition A was applied and heated at 130° C. for 1 minute to form an adhesive layer having a thickness of 13 μm and a protective film having a surface resistance of 2.0×10 ⁹ Ω/□.

<Adhesive composition A>
A monomer composition containing 54.1 parts by weight of 2-ethylhexyl acrylate, 43.2 parts by weight of vinyl acetate, and 2.7 parts by weight of acrylic acid was polymerized to obtain an acrylic polymer (Tg: -32°C). Obtained. 100 parts by weight of the obtained acrylic polymer, 4 parts by weight of an epoxy crosslinking agent (Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), and toluene as a solvent were mixed to prepare an adhesive composition A. .

(Preparation of Laminate II)
A 15 μm thick acrylic adhesive layer is formed on the surface of a 52 μm thick resin film (“Pure Ace RM-147” manufactured by Teijin Limited) that constitutes the retardation layer, and a silicone-based release liner is applied to the surface of the adhesive layer. A polyethylene terephthalate film (thickness: 38 μm, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., “MRF38”) treated with a release agent was laminated to obtain Laminate II.

(Preparation of polarizing plate with protective film)
The release liner of the laminate I was peeled off, and the laminate I was attached to the retardation layer side of the laminate II to obtain a polarizing plate with a protective film.
In addition, each of the above bonding was carried out while being conveyed by rolls.

[Example 2]
A polarizing plate with a protective film was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer of the protective film was 15 μm.

[Example 3]
A polarizing plate with a protective film was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer of the protective film was 18 μm.

[Example 4]
A polarizing plate with a protective film was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer of the protective film was 23 μm.

[Example 5]
A polarizing plate with a protective film was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer of the protective film was 28 m.

[Comparative Example 1]
A polarizing plate with a protective film was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer of the protective film was 5 μm.

[Comparative Example 2]
A polarizing plate with a protective film was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer of the protective film was 10 μm.

[Comparative Example 3]
A polarizing plate with a protective film was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive layer constituting the protective film was formed from the following pressure-sensitive adhesive composition B, and the thickness of the pressure-sensitive adhesive layer was 10 μm. Ta.

<Adhesive composition B>
A monomer composition containing 96.2 parts by weight of 2-ethylhexyl acrylate and 3.8 parts by weight of 2-hydroxyethyl acrylate was polymerized to obtain an acrylic polymer (Tg: -66°C). 100 parts by weight of the obtained acrylic polymer, 3 parts by weight of an aromatic polyisocyanate (manufactured by Tosoh, trade name "Coronate L") as a cross-linking agent, and dioctyltin silaureate (manufactured by Tokyo Fine Chemicals, trade name) as a cross-linking aid. 0.02 parts by weight of the name "Envirizer OL-1"), 0.5 parts by weight of polyoxypropylene glycol (manufactured by Sanyo Kasei, trade name "Sannics PP-3000") as a peeling aid, and 0.5 parts by weight of the solvent Adhesive composition B was prepared by mixing with toluene.

[Comparative Example 4]
A polarizing plate with a protective film was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive layer constituting the protective film was formed from the following pressure-sensitive adhesive composition C and the thickness of the pressure-sensitive adhesive layer was 23 μm. Ta.

<Adhesive composition C>
A monomer composition containing 96.2 parts by weight of 2-ethylhexyl acrylate and 3.8 parts by weight of 2-hydroxyethyl acrylate was polymerized to obtain an acrylic polymer (Tg: -66°C). 100 parts by weight of the obtained acrylic polymer, 5 parts by weight of aliphatic polyisocyanate (manufactured by Tosoh, trade name "Coronate HX") as a cross-linking agent, and dioctyltin silaureate (manufactured by Tokyo Fine Chemicals, trade name) as a cross-linking aid. 0.03 parts by weight of "Envirizer OL-1") and 0.3 parts of polyoxyethylene alkylpropenylphenyl ether sulfate ammonium salt (manufactured by Daiichi Kogyo Seiyaku, trade name "Aqualon HS-10") as a peeling aid. A pressure-sensitive adhesive composition C was prepared by mixing parts by weight and toluene as a solvent.

The examples and comparative examples were evaluated as follows. The evaluation results are summarized in Table 1.
<Evaluation>
1. Shear force (in-plane direction)
The shear force of the protective film against the polarizing plate was measured using a universal tensile compression tester (manufactured by Shimadzu Corporation, product name: AUTOGRAPH AG-X plus). Specifically, as shown in FIG. 4, one end (10 mm × 10 mm) of a sample cut into a size of 10 mm in width and 50 mm in length from the obtained protective film is cut into a size of 70 mm in length and 100 mm in width. The other end (10 mm × 10 mm) of the sample and the center of the lower end of the polarizing plate were sandwiched with a chuck in a state where they were attached to the center of the upper end of the cut-out polarizing plate (surface treatment layer side). The sample was pulled in the longitudinal direction under conditions of a distance of 60 mm and a tensile speed of 0.06 mm/min, and the maximum value of the sample pulled for 2.0 mm was determined as the shear force (unit: N/100 mm ² ). In addition, the measurement was performed under the environment of 23° C. and 50% RH.
2. Modification As shown in FIG. 5, the obtained polarizing plate with a protective film (60 mm long, 60 mm wide) was placed on the upper surface of a test plate P in which a recess having a size of 25 mm long, 25 mm wide, and 1 mm deep was formed on the upper surface. Test piece) S was placed so that the release liner was positioned on the test plate P side. In this state, a bar with a radius of 8 mm is pushed from the upper surface (protective film side) of the protective film-equipped polarizing plate S toward the bottom surface of the central recess of the test plate P, and this state is maintained for 1.0 seconds to remove the bar. When separated from the protective film-attached polarizing plate S, it was confirmed whether or not a pressing mark remained on the protective film-attached polarizing plate S.
(Evaluation criteria)
Good: no impression remains. Poor: impression remains.3. Peeling force A sample with a width of 50 mm and a length of 100 mm was cut from the obtained polarizing plate with a protective film, and a universal tensile tester (manufactured by Shimadzu Corporation, product name "AUTOGRAPH AG-X plus") was used at a peel speed of 300 mm. /min, and the peel force (unit: N/25 mm) when peeled in the longitudinal direction at a peel angle of 180° was measured. Specifically, the peel strength of the protective film from the polarizing plate (surface treatment layer) was measured. In addition, the measurement was performed under the environment of 23° C. and 50% RH.
4. Adhesion During transportation by rolls, it was confirmed whether or not the protective film was lifted or peeled off in the protective film-attached polarizing plate.
(Evaluation criteria)
Good: No lift or peeling of the protective film Poor: Lifting or peeling of the protective film

In Comparative Examples 1 to 3, in the evaluation of deformation, the polarizing plate (polarizing plate with protective film) was deformed by pressing, and the deformation did not recover, leaving a trace.

A polarizing plate obtained by an embodiment of the present invention can be suitably used as a polarizing plate for an image display device. Typical image display devices include liquid crystal display devices, organic EL display devices, and inorganic EL display devices.

REFERENCE SIGNS LIST 10 protective film 11 base film 12 adhesive layer 13 treatment layer 20 laminated film 21 base (protective layer)
22 surface treatment layer 30 polarizer 40 protective layer 50 adhesive layer 52 adhesive layer 60 retardation layer 90 laminate 100 polarizing plate 110 polarizing plate with protective film 200 image display panel (organic EL panel)

Claims (6)

A base film having a first main surface and a second main surface facing each other, and a pressure-sensitive adhesive layer disposed on the first main surface side of the base film,
The peel force to an adherend having a water contact angle of 90° or more is 0.03 N/25 mm or more,
The in-plane shear force on the adherend is 35 N/100 mm ² or less,
Protective film. The protective film according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of more than 10 µm. The pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive, the acrylic pressure-sensitive adhesive contains a (meth)acrylic polymer having a polar functional group, and a polar 3. The protective film according to claim 1, wherein the content of the monomer component having a functional group is 2 parts by weight or more. A protective film according to any one of claims 1 to 3;
A laminated film having a substrate and a surface treatment layer having a water contact angle of 90° or more;
a polarizer;
The protective film is attached to the surface treatment layer,
Polarizer. Laminating the protective film according to any one of claims 1 to 3 to the surface treatment layer of a laminate film having a substrate and a surface treatment layer having a water contact angle of 90 ° or more, and
laminating a polarizer on the substrate side of the laminated film;
A method for manufacturing a polarizing plate, comprising: Laminating the polarizing plate obtained by the manufacturing method according to claim 5 on the image display panel main body,
A method for manufacturing an image display device, comprising:

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