CN105717569A - Polarizing plate with protection film and laminated body comprising same - Google Patents

Abstract

The present invention provides a polarizing plate with a protective film, comprising a polarizing plate having a thickness T1 (μm) including a polarizing plate, and a protective film having a thickness T2 (μm) laminated on one surface thereof, and the thickness of the polarizing plate is 15 μm Hereinafter, the other surface of the polarizing plate is composed of the surface of the first adhesive layer, and the protective film is composed of the second adhesive layer laminated on the above-mentioned one surface of the polarizing plate and a single-layer resin film laminated thereon. , the thickness ratio T2/T1 is in the range of 0.8 to 4, and a laminate including the polarizing plate with the protective film is provided.

Description

Polarizing plate with protective film and laminate including same

technical field

The present invention relates to a polarizing plate with a protective film in which a protective film is laminated on the surface of a polarizing plate, and a laminate including the same.

Background technique

In recent years, in terms of design and portability, mobile terminals such as smartphones have been rapidly increasing in size and size. In order to achieve long-term driving with a limited thickness, high brightness and thinner and lighter weight are also required for the polarizing plate used.

Conventionally, a polarizing plate in which a protective film made of triacetyl cellulose is bonded to both surfaces of a polyvinyl alcohol-based polarizing plate with a polyvinyl alcohol-based adhesive has been widely used. However, in recent years, protective films containing (meth)acrylic resins, chain-like resins, and Various resins such as polyolefin-based resins and cyclic polyolefin-based resins are used as films (for example, refer to paragraph [0005] of JP-A-2004-245925).

Contents of the invention

As described above, in recent years, there is a tendency to use a thin polarizing plate without stiffness. The polarizing plate tends to be easily curled (warped). For example, when the protective films bonded to both surfaces of the polarizing plate contain resins of different types, the polarized plate tends to be easily curled. Polarizing plates are generally distributed on the market as polarizing plates with a protective film attached with a peelable protective film (also referred to as a surface protective film) for protecting the surface. However, polarizing plates with a protective film The above-mentioned tendency is also the same in the plate.

Polarizing plates with excessive curls and polarizing plates with protective films have the following disadvantages, that is, 1) they are broken due to stress applied during the process; 2) due to deformation (distortion) caused by curling, Foreign matter is mixed between the protective film and the polarizing plate; 3) When sticking to the image display element, a sticking error occurs or bubbles are mixed into the sticking interface.

Therefore, an object of the present invention is to provide a polarizing plate with a protective film in which curling is suppressed, and a laminate including the same.

The present invention provides a polarizing plate with a protective film and an image display device shown below.

[1] A polarizing plate with a protective film comprising a polarizing plate having a thickness T1 (μm) including a polarizer, and a protective film having a thickness T2 (μm) laminated on one surface thereof,

The thickness of the polarizer is 15 μm or less,

The other surface of the polarizing plate is constituted by the surface of the first adhesive layer,

The protective film is composed of a second adhesive layer laminated on the one surface and a single-layer resin film laminated thereon,

Thickness ratio T2/T1 exists in the range of 0.8-4.

[2] The polarizing plate with a protective film according to [1], further comprising a separator laminated on the other surface of the polarizing plate.

[3] The polarizing plate with a protective film according to [1] or [2], wherein the protective film has a thickness T2 of 60 μm or more.

[4] The polarizing plate with a protective film according to any one of [1] to [3], wherein the polarizing plate further includes an optical film other than the polarizing plate,

The protective film is laminated on the surface of the optical film.

[5] The polarizing plate with a protective film according to [4], wherein the optical film is a brightness improving film.

[6] The polarizing plate with a protective film according to any one of [1] to [5], wherein the resin film contains a polyester-based resin.

[7] A laminate comprising an image display element and the polarizing plate with a protective film according to any one of [1] to [6] laminated thereon.

According to the present invention, a polarizing plate with a protective film in which curling is suppressed, and a laminate including the same can be provided. The polarizing plate with a protective film and the laminated body containing it can be used suitably for an image display device.

Description of drawings

FIG. 1 is a schematic cross-sectional view schematically showing an example of the layer configuration of a polarizing plate with a protective film according to the present invention.

Fig. 2 is a schematic cross-sectional view showing an example of the layer configuration of the polarizing plate with a protective film of the present invention.

3 is a schematic cross-sectional view showing another example of the layer configuration of the polarizing plate with a protective film of the present invention.

4 is a schematic cross-sectional view showing another example of the layer configuration of the polarizing plate with a protective film of the present invention.

detailed description

＜Polarizing plate with protective film＞

(1) Configuration of polarizing plate with protective film

FIG. 1 is a schematic cross-sectional view schematically showing an example of the layer configuration of a polarizing plate with a protective film according to the present invention. An example of the polarizing plate with a protective film of the present invention will be described with reference to FIG. 1 . The polarizing plate with a protective film of the present invention includes a polarizing plate 100 including a polarizing plate (not shown in FIG. 1 ), and a protective film 60 laminated on one surface thereof. The other surface of polarizing plate 100 , that is, the surface opposite to the surface on which protective film 60 is laminated, is formed by the surface of first adhesive layer 31 . In other words, the outermost layer of the polarizing plate 100 opposite to the surface where the protective film 60 is laminated is the first pressure-sensitive adhesive layer 31 . On the outer surface of the first adhesive layer 31 (the other surface of the polarizing plate 100 ), a peelable release film 70 may be laminated for temporary protection of the surface. On the other hand, the surface of the polarizing plate 100 on the protective film 60 side (the surface to which the protective film 60 is bonded) may be, for example, the surface of a protective film, another optical film, or a layer added to a film.

The protective film 60 is composed of a resin film (base film) 61 and a second adhesive layer 62 laminated thereon, and is bonded and laminated on the polarizing plate 100 via the adhesive layer.

The so-called polarizing plate 100 in the present invention is a polarizing element including at least a polarizing plate and a first adhesive layer 31 , and usually includes a protective film attached to one or both sides thereof. In addition to the protective film, the polarizing plate 100 may include another optical film such as a film having an optical function different from that of the polarizer, or a layer added to the film such as an optical layer. Various optical films including a protective film can be bonded via an adhesive layer or an adhesive layer. As described above, one of the outermost layers of the polarizing plate 100 is the first adhesive layer 31, so even if the separator 70 is laminated on the first adhesive layer 31, the separator 70 is not included in the polarizing plate 100. .

When the thickness of the polarizing plate 100 is T1 (μm), and the thickness of the protective film 60 is T2 (μm), the thickness ratio T2/T1 is set within the range of 0.8-4. Thereby, curling (warpage) of the polarizing plate with a protective film can be suppressed effectively.

The polarizing plate with a protective film of the present invention is usually a single body of a polarizing plate with a protective film. This single sheet can be obtained by laminating another raw material film continuously unwound from the film roll on the raw material film continuously unwound from the film roll and conveying, and the resulting long-sized The laminated film is wound into a roll, and a long polarizing plate with a protective film is produced by this so-called roll-to-roll method, and then cut.

The shape of the above-mentioned single sheet is not particularly limited, however, it is preferably a square shape having a long side and a short side, typically a rectangle. The lengths of the long side and the short side are not particularly limited, but usually the long side of the single sheet is 50 mm or more, and the short side is 30 mm or more. The larger the size of the single sheet, the easier it is to generate curls. In cases where the dimensions (long side and/or short side) are too small, the problem of curling itself is difficult to occur.

Hereinafter, examples of the layer configuration of the polarizing plate 100 will be described with reference to FIGS. 2 to 4 , but the layer configuration is not limited to these examples.

The polarizing plate of the polarizing plate with protective film shown in FIG. The outer surface of the first adhesive layer 31 constitutes. The polarizing plate of the polarizing plate with protective film shown in FIG. The first adhesive layer 31 on the outer surface of the protective film 21 and the brightness improving film 50 as an optical film laminated on the outer surface of the protective film 21 through the third adhesive layer 32 are constituted. The polarizing plate of the polarizing plate with a protective film shown in FIG. Constructed of the same layers as the polarizing plate.

Although illustration is omitted, bonding of the polarizing plate 10 and the protective films 21 and 22 can be performed using an adhesive.

(2) Polarizer

The polarizer 10 is an absorption-type polarizer having the property of absorbing linearly polarized light having a vibration plane parallel to its absorption axis and transmitting linearly polarized light having a vibration plane perpendicular to the absorption axis (parallel to the transmission axis), A polarizing film obtained by adsorbing and orientating a polyvinyl alcohol-based resin film with a dichroic dye can be suitably used. The polarizing plate 10 can be utilized, for example, including: a process of uniaxially stretching a polyvinyl alcohol-based resin film; a process of dyeing a polyvinyl alcohol-based resin film with a dichroic dye to adsorb a dichroic dye; The polyvinyl alcohol-based resin film of the dichroic dye is produced by the process of treating the boric acid aqueous solution; and the process of washing with water after the treatment by the boric acid aqueous solution.

As the polyvinyl alcohol-based resin, a resin obtained by saponifying a polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, copolymers with other monomers copolymerizable with vinyl acetate, and the like. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having ammonium groups, and the like.

The saponification degree of polyvinyl alcohol-type resin is 85-100 mol% normally, Preferably it is 98 mol% or more. The polyvinyl alcohol-based resin may also be modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1,000 to 10,000, preferably 1,500 to 5,000. The average degree of polymerization of polyvinyl alcohol-type resin can be calculated|required according to JISK6726.

What formed such a polyvinyl-alcohol-type resin into a film is used as the raw material film of the polarizing plate 10 (polarizing film). The method of forming a polyvinyl alcohol-based resin into a film is not particularly limited, and known methods can be employed. The thickness of the polyvinyl alcohol-based original film is not particularly limited, but in order to make the thickness of the polarizing plate 10 15 μm or less, a film of 5 to 35 μm is usually used, preferably 20 μm or less. If it is desired to stretch a polyvinyl alcohol-based raw material film with a thickness greater than 35 μm to obtain a polarizing plate 10 with a thickness of 15 μm or less, it is necessary to increase the stretching ratio. Dimensional shrinkage also increases. Moreover, when thickness is less than 5 micrometers, since the handling property at the time of stretching falls, it becomes easy to generate|occur|produce troubles, such as cutting|disconnection at the time of polarizing plate manufacture.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing of the dichroic dye, simultaneously with dyeing, or after dyeing. When performing uniaxial stretching after dyeing, this uniaxial stretching may be performed before boric-acid treatment or during boric-acid treatment. In addition, uniaxial stretching may be performed in these multiple stages.

In the case of uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using heated rolls. In addition, the uniaxial stretching may be a dry stretching in which stretching is performed in the air, or a wet stretching in which a polyvinyl alcohol-based resin film is stretched using a solvent or water. The draw ratio is usually 3 to 8 times.

As a method of dyeing a polyvinyl alcohol-type resin film with a dichroic dye, the method of immersing this film in the aqueous solution containing a dichroic dye can be employ|adopted, for example. As the dichroic dye, iodine or a dichroic organic dye can be used. Furthermore, it is preferable that the polyvinyl-alcohol-type resin film implements the immersion process in water before dyeing process.

As a dyeing process with iodine, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is generally employed. The iodine content in the aqueous solution is usually 0.01 to 1 part by weight per 100 parts by weight of water. The content of potassium iodide is usually 0.5-20 parts by weight per 100 parts by weight of water. In addition, the temperature of this aqueous solution is normally 20-40 degreeC. On the other hand, as a dyeing process with a dichroic organic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic organic dye is generally employed. The aqueous solution containing a dichroic organic dye may contain inorganic salts such as sodium sulfate as a dyeing auxiliary. The content of the dichroic organic dye in the aqueous solution is usually 1×10 ⁻⁴ to 10 parts by weight per 100 parts by weight of water. The temperature of this aqueous solution is normally 20-80 degreeC.

As the boric acid treatment after dyeing with a dichroic dye, a method of immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid is generally employed. When iodine is used as the dichroic dye, the aqueous solution containing boric acid preferably contains potassium iodide. The quantity of the boric acid in the aqueous solution containing boric acid is 2-15 weight part normally per 100 weight part of water. The quantity of the potassium iodide in this aqueous solution is 0.1-15 weight part normally per 100 weight part of water. The temperature of the aqueous solution may be 50°C or higher, for example, 50-85°C.

The polyvinyl alcohol-type resin film after a boric-acid process is normally washed with water. The water washing treatment can be performed, for example, by immersing the boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of water in the water washing treatment is usually 5 to 40°C.

After washing with water, a drying treatment was performed to obtain a polarizing plate 10 . Drying can be performed using a hot air dryer or a far-infrared heater. The thickness of the polarizing plate 10 is 15 μm or less, preferably 10 μm or less. Setting the thickness of the polarizing plate 10 to 15 μm or less is advantageous for reducing the thickness of the polarizing plate 100 and further reducing the thickness of the image display device. The thickness of the polarizing plate 10 is usually 2 μm or more (for example, 5 μm or more). According to the present invention, even if the thickness of the polarizing plate 10 is as thin as 15 μm or less, curling of the polarizing plate with a protective film can be suppressed.

The moisture content of the polarizing plate 10 is reduced to a practical level by the drying treatment. The water content thereof is usually 5 to 20% by weight, preferably 8 to 15% by weight. If the water content is 5% by weight or less, the flexibility of the polarizing plate 10 will be lost, and the polarizing plate 10 may be damaged or broken after drying. Moreover, when the moisture content is 20 weight% or more, the thermal stability of the polarizing plate 10 may be inferior.

(3) Protective film

The protective films 21 and 22 that can be laminated on one side or both sides of the polarizing plate 10 can be made of a thermoplastic resin having light transmission (preferably optically transparent), such as a chain polyolefin-based resin (polypropylene-based resin, etc.), Polyolefin-based resins such as cyclic polyolefin-based resins (norbornene-based resins, etc.); cellulose-based resins such as triacetylcellulose and diacetylcellulose; polyethylene terephthalate, polyethylene Polyester-based resins such as butylene terephthalate; polycarbonate-based resins; (meth)acrylic resins such as methyl methacrylate-based resins; polystyrene-based resins; polyvinyl chloride-based resins Resin; acrylonitrile/butadiene/styrene resin; acrylonitrile/styrene resin; polyvinyl acetate resin; polyvinylidene chloride resin; polyamide resin; polyacetal resin; modified poly Films of phenylene ether-based resins; polysulfone-based resins; polyethersulfone-based resins; polyarylate-based resins; polyamide-imide-based resins; polyimide-based resins, etc. Among them, polyolefin-based resins and cellulose-based resins are preferably used. In addition, "(meth)acrylic resin" in this specification means at least 1 sort(s) chosen from acrylic resin and methacrylic resin. The same applies to other terms including "(methyl)".

Examples of the chain polyolefin-based resin include copolymers composed of two or more chain olefins, in addition to homopolymers of chain olefins such as polyethylene resins and polypropylene resins.

Cyclic polyolefin-based resins are a general term for resins polymerized with cyclic olefins as polymerization units. Specific examples of cyclic polyolefin resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, and chain olefins such as ethylene and propylene between cyclic olefins Copolymers (typically random copolymers), graft polymers modified with unsaturated carboxylic acids or their derivatives, and their hydrogenated products. Among them, a norbornene-based resin using a norbornene-based monomer such as norbornene or a condensed-ring norbornene-based monomer as a cyclic olefin is preferably used.

The so-called cellulose-based resin means that some or all of the hydrogen atoms in the hydroxyl groups of cellulose obtained from raw material cellulose such as cotton linters (cotton linter) or wood pulp (hardwood pulp, coniferous wood pulp) are replaced with acetyl, propylene, etc. Acyl and/or butyryl substituted organic acid esters of cellulose or mixed organic acid esters of cellulose. For example, the resin which consists of acetate, a propionate, a butyrate of cellulose, and these mixed esters etc. is mentioned. Among them, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate are preferable.

A (meth)acrylic resin is a polymer containing a structural unit derived from a (meth)acrylic monomer. The polymer is typically a methacrylate-containing polymer. It is preferable that the ratio of the structural unit derived from a methacrylate is a polymer containing 50 weight% or more with respect to all structural units. The (meth)acrylic resin may be a homopolymer of methacrylate or a copolymer containing a structural unit derived from another polymerizable monomer. In this case, the proportion of structural units derived from other polymerizable monomers is preferably 50% or less with respect to all structural units.

As the methacrylate that can constitute the (meth)acrylic resin, an alkyl methacrylate is preferable. Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, and isobutyl methacrylate. , tert-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate and other alkyl methacrylates with 1 to 8 carbon atoms base ester. The number of carbon atoms of the alkyl group contained in the alkyl methacrylate is preferably 1-4. In (meth)acrylic resin, methacrylate may be used individually by 1 type, and may use 2 or more types together.

Examples of the other polymerizable monomers that can constitute the (meth)acrylic resin include acrylate and other compounds having a polymerizable carbon-carbon double bond in the molecule. Other polymerizable monomers may be used alone or in combination of two or more. As the acrylate, an alkyl acrylate is preferable. Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, An alkyl acrylate having an alkyl group having 1 to 8 carbon atoms such as cyclohexyl acrylate and 2-hydroxyethyl acrylate. It is preferable that the carbon number of the alkyl group contained in an alkyl acrylate is 1-4. In (meth)acrylic resin, acrylate may be used individually by 1 type, and may use 2 or more types together.

Examples of other compounds having a polymerizable carbon-carbon double bond in the molecule include vinyl compounds such as ethylene, propylene, and styrene, and vinyl cyanide compounds such as acrylonitrile. Other compounds having a polymerizable carbon-carbon double bond in the molecule may be used alone or in combination of two or more.

It is also useful to control the retardation value of the protective films 21 and 22 to a value suitable for image display devices such as liquid crystal display devices. For example, in an in-plane switching (IPS) mode liquid crystal display device, it is preferable to use a film having a retardation value of substantially zero as the protective film 22 . The term "retardation value is substantially zero" means that the in-plane retardation value R ₀ at a wavelength of 590 nm is 10 nm or less, the absolute value of the retardation value R _th in the thickness direction at a wavelength of 590 nm is 10 nm or less, and that at a wavelength of 480 to 750 nm The absolute value of the retardation value R _th in the thickness direction is 15 nm or less.

Depending on the mode of the liquid crystal display device, the protective films 21 and 22 may be stretched and/or shrunk to give an appropriate retardation value. For example, a phase difference layer (or film) of a single-layer or multi-layer structure may be used as the protective film 22 for the purpose of compensating the viewing angle. In this case, the polarizing plate 100 may be an elliptically polarizing plate or a circular polarizing plate having a laminated structure including the polarizing plate 10 and a retardation layer, or a polarizing plate including a retardation layer and having a viewing angle compensation function.

The thickness of the protective films 21 and 22 is usually 1 to 100 μm, but is preferably 5 to 60 μm, more preferably 5 to 50 μm, from the viewpoint of strength and handling properties. If the thickness is within this range, the polarizing plate 10 can be mechanically protected, and the polarizing plate 10 can maintain stable optical characteristics without shrinking even when exposed to a humid and hot environment. Although the thinner the protective films 21 and 22 are, curling is more likely to occur. However, according to the present invention, even if the thickness of the protective films 21 and 22 is as thin as 30 μm or less, curling can be suppressed.

From the viewpoint of thinning, the polarizing plate 100 may not have at least one of the protective films 21 and 22 , but it is preferable to have a protective film on at least one surface of the polarizing plate 10 . Although curling tends to occur when the protective film is laminated on only one surface of the polarizing plate 10, according to the present invention, curling can be suppressed even in such a case.

In the case where the protective film is laminated on only one surface of the polarizer 10, the surface of the polarizer 10 opposite to the surface on which the protective film is laminated may be provided with the same active energy ray-curable adhesive as described later. A protective layer formed of an active energy ray curable resin composition. By providing the protective layer, even if the protective film is provided on only one surface of the polarizing plate 10 , it is possible to more effectively suppress curling caused by changes in humidity or deterioration of the polarizing plate 10 .

When protective films are bonded to both surfaces of the polarizing plate 10 , these protective films may be composed of the same type of thermoplastic resin or may be composed of different types of thermoplastic resins. In addition, the thickness may be the same or different. In addition, they may have the same phase difference characteristics or may have different phase difference characteristics.

At least any one of the protective films 21, 22 may also be equipped with a hard coat layer, an anti-glare layer, a light diffusion layer, and a retardation layer (having a wavelength of 1/4) on its outer surface (the surface opposite to the polarizer 10). Phase difference layer, etc.), anti-reflection layer, anti-static interference layer, anti-fouling layer and other surface treatment layers (coatings) or protective films for optical layers.

If the configurations (resin type, thickness, presence or absence of surface treatment layer, etc.) of the protective films laminated on both sides of the polarizing plate 10 are different from each other, curling is likely to occur, but according to the present invention, curling can be suppressed even in such a case.

The protective films 21 and 22 can be bonded to the polarizing plate 10 via an adhesive layer, for example. As the adhesive for forming the adhesive layer, a water-based adhesive, an active energy ray-curable adhesive, or a thermosetting adhesive can be used, preferably a water-based adhesive or an active energy ray-curable adhesive. .

Examples of the water-based adhesive include an adhesive composed of a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. Among them, a water-based adhesive composed of a polyvinyl alcohol-based resin aqueous solution is suitably used. As the polyvinyl alcohol-based resin, in addition to a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate which is a homopolymer of vinyl acetate, it is also possible to use vinyl acetate and other monomers that can be copolymerized with it. Polyvinyl alcohol-based copolymers obtained by saponification of copolymers, or modified polyvinyl alcohol-based polymers whose hydroxyl groups are partially modified. The water-based adhesive may contain crosslinking agents such as aldehyde compounds (glyoxal, etc.), epoxy compounds, melamine compounds, methylol compounds, isocyanate compounds, amine compounds, and polyvalent metal salts.

When using a water-based adhesive, after bonding the polarizing plate 10 and the protective films 21 and 22 together, it is preferable to implement the drying process for removing the water contained in a water-based adhesive. After the drying step, an aging step for aging may be provided. The temperature during aging is usually 20-45°C.

The above-mentioned active energy ray-curable adhesive refers to an adhesive that is cured by irradiating active energy rays such as ultraviolet rays or electron beams, and examples thereof include curable combinations containing a polymerizable compound and a photopolymerization initiator. products, curable compositions containing photoreactive resins, curable compositions containing binder resins and photoreactive crosslinking agents, etc. Preferably, it is an ultraviolet curable adhesive. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable (meth)acrylic monomers, photocurable urethane monomers, or photopolymerizable monomers derived from Oligomers of photopolymerizable monomers. Examples of the photopolymerization initiator include those containing a substance that generates active centers such as neutral radicals, anion radicals, and cationic radicals by irradiation with active energy rays. As an active energy ray-curable adhesive containing a polymerizable compound and a photopolymerization initiator, a curable composition containing a photocurable epoxy-based monomer and a photocationic polymerization initiator, a photocurable (methanol) radical) a curable composition of an acrylic monomer and a photoradical polymerization initiator, or a mixture of these curable compositions.

As a photocurable epoxy monomer, an alicyclic epoxy compound is preferable. The term "alicyclic epoxy compound" refers to a compound having a structure in which one or more carbon atoms of an alicyclic ring form an oxirane ring in the molecule. An alicyclic epoxy compound may be used individually by 1 type, and may use 2 or more types together. The term "a structure in which an oxirane ring is formed together with carbon atoms of an alicyclic ring" refers to a group obtained by removing one or more hydrogen atoms from (CH ₂ ) _m in the structure shown below. group. In the following formula, m is an integer of 2-5.

[chemical 1]

Therefore, a compound in which a group obtained by removing one or more hydrogen atoms in (CH ₂ ) _m is bonded to another chemical structure can become an alicyclic epoxy compound. One or more hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with linear alkyl groups such as methyl and ethyl groups. Among the alicyclic epoxy compounds, it is preferable to have an oxabicyclohexane ring (m=4 in the above formula) or an oxabicycloheptane ring ( alicyclic epoxy compound in which m=5 in the above formula). The alicyclic epoxy compounds preferably used are specifically exemplified below.

[Chem 2]

In the case of using an active energy ray-curable adhesive, after bonding the polarizer 10 and the protective films 21 and 22, a drying process is performed as necessary, and then the active energy ray-curable adhesive is irradiated with active energy rays. The curing process of adhesive curing. Therefore, when an active energy ray-curable adhesive is used, the adhesive layer is a cured product layer. The light source of active energy rays is not particularly limited, but ultraviolet rays having a luminescence distribution below a wavelength of 400 nm are preferred. Specifically, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, chemical lamps, black light lamps, and microwave-excited mercury lamps can be used. , metal halide lamps, etc.

When bonding the polarizing plate 10 and the protective films 21 and 22 , saponification treatment, corona treatment, plasma treatment, etc. may be performed on at least one bonding surface of them in order to improve adhesiveness.

When bonding protective films to both surfaces of the polarizing plate 10 , the adhesives for bonding these protective films may be the same type of adhesives or different types of adhesives. Although curling tends to occur when a different kind of adhesive is used, according to the present invention, curling can also be suppressed in such a case.

(4) Other optical films

The polarizing plate 100 may include other optical films than the polarizing plate 10 and the protective films 21 and 22 , and representative examples thereof are the brightness improving film 50 and retardation film. In the case where the polarizing plate 100 includes another optical film, the protective film 60 may also be laminated on the surface of the optical film.

The brightness improving film 50 is also called a reflective polarizing film, and uses a polarization conversion element having a function of separating light emitted from a light source (backlight) into transmitted polarized light, reflected polarized light, or scattered polarized light. By arranging the brightness improving film 50 on the polarizing plate 10, the output efficiency of the linearly polarized light emitted from the polarizing plate 10 can be improved by utilizing the returned light (reflected light) as reflected polarized light or scattered polarized light. The brightness improving film 50 may be laminated on the polarizing plate 10 via an adhesive layer (third adhesive layer 32 ). Another film such as a protective film may be interposed between the polarizing plate 10 and the brightness improvement film 50 .

The brightness enhancement film 50 may be, for example, an anisotropic reflective polarizer. An example of an anisotropic reflective polarizer is an anisotropic multilayer film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction. A specific example is "DBEF" manufactured by 3M Corporation (see JP Kaiping No. 4-268505 bulletin, etc.). Another example of an anisotropic reflective polarizer is a composite of a cholesteric liquid crystal layer and a λ/4 plate, a specific example of which is "PCF" manufactured by Nitto Denko (see JP-A-11-231130, etc.). Another example of an anisotropic reflective polarizer is a reflective grating polarizer, and a specific example is a metal grid reflective polarizer that emits reflected polarized light even in the visible light region after microfabrication of metal (see US Patent No. 6,288,840, etc.) . A film obtained by adding metal fine particles to a polymer matrix and stretching it (refer to Japanese Patent Application Laid-Open No. 8-184701, etc.).

Surface activation treatment may be performed in advance on the bonding surface with the 3rd pressure-sensitive adhesive layer 32 in the brightness improvement film 50. Thereby, it is possible to obtain the polarizing plate 100 that is less prone to peeling between the third pressure-sensitive adhesive layer 32 and the brightness improving film 50 in a hot and humid environment and has excellent durability against wet heat. Examples of surface activation treatment include corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, ionizing active ray treatment (ultraviolet treatment, electron beam treatment, etc.) Dry treatment such as water or acetone or other solvents, such as ultrasonic treatment, alkali treatment, and anchor coating (anka-coat) treatment, such as wet treatment. These treatments may be performed individually or in combination of two or more. Among these, corona treatment and plasma treatment are preferable from the viewpoint of continuously processing a roll-shaped film.

On the outer surface of the brightness improving film 50, a hard coat layer, an antiglare layer, a light diffusion layer, a phase difference layer (a phase difference layer having a phase difference value of 1/4 wavelength, etc.), an antireflection layer, an antistatic layer, etc. can also be provided. Surface treatment layers (coatings) such as interference layers, antifouling layers, or optical layers. Formation of this layer can improve the adhesiveness with the backlight tape and the uniformity of the displayed image. The thickness of the brightness improvement film 50 is usually 10 to 100 μm, but from the viewpoint of thinning the polarizing plate 100, it is preferably 10 to 50 μm, and more preferably 10 to 30 μm.

(5) Adhesive layer (pressure-sensitive adhesive layer)

The first adhesive layer 31 is an adhesive layer disposed on the outermost surface of the polarizing plate 100, and can be used to bond the polarizing plate with a protective film on an image display element (such as a liquid crystal unit) or other optical components. . The third adhesive layer 32 is used to bond the optical films constituting the polarizing plate 100 (for example, another optical film such as the brightness improving film 50 and the polarizing plate 10 or the protective film 21 ). The first adhesive layer 31 and the third adhesive layer 32 can be made of resins such as (meth)acrylic, rubber, urethane, ester, silicone, and polyvinyl ether. Consists of an adhesive composition as the main component. Among them, an adhesive composition using a (meth)acrylic resin excellent in transparency, weather resistance, heat resistance, etc. as a matrix polymer is suitable. The adhesive composition may be an active energy ray-curable type or a heat-curable type.

As the (meth)acrylic resin (matrix polymer) used in the adhesive composition, for example, butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate A polymer or copolymer of one or more monomers of (meth)acrylates such as 2-ethylhexyl (meth)acrylate. In the matrix polymer, polar monomers are preferably copolymerized. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethyl A monomer having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as aminoethyl (meth)acrylate and glycidyl (meth)acrylate.

The adhesive composition can also contain only the aforementioned matrix polymers, but usually also crosslinkers. Examples of the crosslinking agent include metal ions having a divalent or higher valence and forming a metal carboxylate salt with a carboxyl group; crosslinking agents belonging to a polyamine compound and forming an amide bond with a carboxyl group ; A cross-linking agent that belongs to polyepoxides or polyols and forms an ester bond with a carboxyl group; a cross-linking agent that belongs to a polyisocyanate compound and forms an amide bond with a carboxyl group. Among them, polyisocyanate compounds are preferable.

The so-called active energy ray-curable adhesive composition is an adhesive composition having the property that it is cured by irradiation with active energy rays such as ultraviolet rays or electron beams. It also has adhesiveness and can be adhered to adherends such as films, and can be cured by irradiation of active energy rays to adjust the adhesive force. The active energy ray-curable adhesive composition is preferably an ultraviolet-curable type. The active energy ray-curable adhesive composition contains an active energy ray polymerizable compound in addition to a matrix polymer and a crosslinking agent. Moreover, a photoinitiator, a photosensitizer, etc. may be contained as needed.

The adhesive composition may contain fine particles for imparting light scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than matrix polymers, tackifiers, fillers (metal powders or other inorganic powders) etc.), antioxidants, UV absorbers, dyes, pigments, colorants, defoamers, preservatives, photopolymerization initiators and other additives.

The first adhesive layer 31 and the third adhesive layer 32 can be formed by applying an organic solvent dilution of the above-mentioned adhesive composition on a base material and drying it. The substrate may be polarizing plate 10 , protective films 21 , 22 , other optical films such as brightness improvement film 50 , isolation film (for example, isolation film 70 ), and the like. When an active energy ray-curable adhesive composition is used, the formed adhesive layer can be irradiated with active energy rays to obtain a cured product having a desired degree of curing.

The thickness of the first adhesive layer 31 and the third adhesive layer 32 may be 1 to 40 μm, but from the viewpoint of thinning the polarizing plate 100 and suppressing the dimensional change of the polarizing plate 100 while maintaining good processability From the viewpoint of , it is preferably 3 to 25 μm (for example, 3 to 20 μm, more preferably 3 to 15 μm).

The third adhesive layer 32 preferably exhibits a storage elastic modulus of 0.15 to 1 MPa in a temperature range of 23 to 80°C. Accordingly, it is possible to suppress dimensional changes that tend to occur with shrinkage of the polarizing plate 10 in a hot and humid environment, thereby improving the durability of the polarizing plate 100 . In addition, since the movement of the polarizing plate 100 can be suppressed even when the image display device equipped with the polarizing plate 100 is placed in a hot and humid environment, the reliability of the image display device can be improved.

"Showing a storage elastic modulus of 0.15 to 1 MPa in a temperature range of 23 to 80° C." means that the storage elastic modulus is a value within the above-mentioned range at any temperature in this range. Since the storage modulus of elasticity generally decreases gradually with increasing temperature, if the storage modulus of elasticity at 23°C and 80°C both fall within the above-mentioned range, it can be regarded as exhibiting the above-mentioned range at the temperature of this range. storage modulus of elasticity. The storage elastic modulus of the third pressure-sensitive adhesive layer 32 can be measured using a commercially available viscoelasticity measuring device, for example, a viscoelasticity measuring device "DYNAMICANALYZERRDAII" manufactured by REOMETRIC Corporation.

As a method for adjusting the storage elastic modulus to the above-mentioned range, it is possible to add an oligomer to the matrix polymer or to an adhesive composition further containing a crosslinking agent. An active energy ray-curable adhesive composition (preferably an ultraviolet-curable adhesive composition) is prepared from a urethane (meth)acrylate-based oligomer. It is more preferable to moderately harden an adhesive layer by irradiating an active energy ray.

The storage elastic modulus of the first adhesive layer 31 may be the same as or different from that of the third adhesive layer 32 .

(6) Isolation film

The separator 70 is a film temporarily attached to protect the surface of the first pressure-sensitive adhesive layer 31 before bonding the image display element (such as a liquid crystal cell) or other optical members. The separator 70 is usually made of a thermoplastic resin film that has been subjected to a release treatment on one side, and the release treatment surface is bonded to the first adhesive layer 31 . The thermoplastic resin constituting the separator 70 may be, for example, polyethylene-based resins such as polyethylene, polypropylene-based resins such as polypropylene, polyethylene terephthalate, or polyethylene naphthalate. polyester resin, etc. On the surface of the third pressure-sensitive adhesive layer 32 , in order to temporarily protect the surface before laminating an optical film such as the brightness improvement film 50 , the same separator as above may be attached. The thickness of the isolation film 70 is, for example, 10 to 50 μm.

(7) Protective film

The protective film 60 is composed of a resin film 61 and a second adhesive layer 62 laminated thereon. The protective film 60 is a film for protecting the surface of the polarizing plate 100, and is usually bonded together with the second adhesive layer 62 therein after the polarizing plate with the protective film is bonded on, for example, an image display element or other optical members. Peel off.

The resin constituting the resin film 61 may be, for example, polyethylene-based resins such as polyethylene, polypropylene-based resins such as polypropylene, polyethylene terephthalate or polyethylene naphthalate, or the like. Thermoplastic resins such as polyester-based resins and polycarbonate-based resins. Polyester-based resins such as polyethylene terephthalate are preferable. The resin film 61 may have a single-layer structure or a multi-layer structure, but it is preferably a single-layer structure from the viewpoint of ease of manufacture, manufacturing cost, and the like. Regarding the second adhesive layer 62 , the above-mentioned descriptions about the first adhesive layer 31 and the third adhesive layer 32 can be cited.

(8) Thickness ratio of protective film to polarizing plate

The ratio T2/T1 of the thickness T2 (μm) of the protective film 60 to the thickness T1 (μm) of the polarizing plate 100 is set within a range of 0.8-4. By making T2/T1 0.8 or more, curling can be suppressed significantly compared with the case of less than 0.8. T2/T1 is preferably 1 or more. When T2/T1 exceeds 4, it is disadvantageous from the viewpoint of the thickness of the polarizing plate with a protective film, and manufacturing cost. Since the protective film 60 is a film that is peeled off after the actual use of the polarizing plate with the protective film (for example, after it is attached to an image display element), and does not remain in the final product, even if the protective film 60 is enlarged The thickness T2 of the film does not hinder the thinning of the image display device to which the polarizing plate with a protective film is applied.

The thickness T2 of the protective film 60 may be, for example, 60-200 μm, preferably 70-150 μm, more preferably 80-120 μm. When the thickness T2 is less than 60 μm, it may be difficult to make the thickness ratio T2/T1 within the above-mentioned range. Moreover, when thickness T2 exceeds 200 micrometers, it will be disadvantageous from the viewpoint of cost, roll conveyance property, and the reworkability of the protective film 60. On the other hand, the thickness T1 of the polarizing plate 100 is usually 20 to 200 μm, preferably 30 to 150 μm, more preferably 40 to 120 μm, even more preferably 50 to 100 μm.

The present invention is particularly advantageous in a case where the polarizing plate 100 included in the protective film-attached polarizing plate has an asymmetrical layer structure with respect to the polarizing plate 10 and has a structure that is prone to curling. Examples of compositions that tend to cause curls are shown below.

(a) Polarizing plate 10 and/or protective film 21, 22 thin constitution;

(b) The adhesive layer interposed between the polarizer 10 and the protective film is a cured product layer of an active energy ray-curable adhesive;

(c) Only one side of the polarizing plate 10 is pasted with a protective film;

(d) A protective film is attached to one surface of the polarizing plate 10, and an optical film (brightness improvement film, etc.) other than the protective film is attached to the other surface;

(e) The configuration (type of resin, thickness, presence or absence of a surface treatment layer, etc.) of the protective film bonded to both sides of the polarizing plate 10 is different from each other;

(f) The adhesive layer for laminating the protective film on both sides of the polarizing plate 10 is formed of different types of adhesives;

(g) A protective film is pasted on both sides of the polarizing plate 10, and another optical film is pasted on one of the protective films;

(h) There is also a configuration in which the total number of films and layers on one side is different from the total number of films and layers on the other side based on the polarizing plate 10 .

<Laminated body, liquid crystal panel and image display device>

The polarizing plate with a protective film of the present invention can be suitably applied to a laminate including an image display element and a polarizing plate with a protective film laminated thereon. The polarizing plate with a protective film in this laminate can be bonded to the image display element via the first adhesive layer 31 (after peeling and removing the separator 70 ). After bonding the polarizing plate with a protective film to the image display element, the protective film 60 is peeled and removed at desired timing. This laminated body may be a liquid crystal panel including an image display element and polarizing plates laminated on one or both surfaces thereof, or a production intermediate thereof. The protective film 60 is peeled and removed after constructing a laminate, constructing a liquid crystal panel with the protective film 60 bonded thereto, or constructing an image display device using the liquid crystal panel with the protective film 60 bonded thereto. Usually, in a final product as an image display device, the protective film 60 is peeled off.

The image display device may be any device such as a liquid crystal display device or an organic EL display device, but is preferably a liquid crystal display device. A liquid crystal display device includes a liquid crystal panel including a liquid crystal cell as an image display element, and a backlight. When constructing a liquid crystal display device, the polarizing plate with a protective film of the present invention can be used in a polarizing plate arranged on the viewing side, can also be used in a polarizing plate arranged on the backlight side, and can also be used in the viewing side and the backlight. Of the polarizing plates on both sides, it is preferable to use the polarizing plate with a protective film of the present invention at least in the polarizing plate on the backlight side.

[Example]

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to these examples. In the following examples, the thickness of the film or layer constituting the polarizing plate with protective film, the in-plane retardation value R ₀ and the thickness direction retardation value R _th of the film, the storage elastic modulus of the adhesive layer, and The curl amount of the polarizing plate with a protective film was measured by the following method.

(1) Thickness

It measured using the digital micrometer "MH-15M" manufactured by Nikon Corporation.

(2) In-plane retardation value R _e and thickness direction retardation value R _th

Using "KOBRA-ADH" manufactured by Oji Scientific Instruments Co., Ltd., which is a phase difference meter based on the principle of the parallel Nicol rotation method, it measured at 23 degreeC with the light of wavelength 590nm, 483nm, or 755nm.

(3) Storage elastic modulus

The storage elastic modulus G' of the pressure-sensitive adhesive layer is measured in accordance with the following (I) to (III).

(I) Take out 2 samples at a time of 25 ± 1 mg from the adhesive layer, and shape each into a substantially spherical shape.

(II) Attach the obtained approximately spherical sample to the upper and lower surfaces of the I-shaped jig, and clamp both the upper and lower surfaces with the L-shaped jig. The configuration of the measurement sample is L-shaped jig/adhesive/I-shaped jig/adhesive/L-shaped jig.

(III) Using a dynamic viscoelasticity measuring device "DVA-220" manufactured by IT Measurement Control Co., Ltd., the storage elasticity of the thus prepared sample was measured under the conditions of a temperature of 23°C or 80°C, a frequency of 1Hz, and an initial strain of 1N. Modulus G'.

(4) Amount of curl

The sheet|seat of the polarizing plate with the protective film in the state which laminated|stacked the separator was placed on the flat table so that the convex side may face down. In this state, the heights of the four corners from the flat table were measured, and the average value thereof was defined as the amount of primary curl. Moreover, the same measurement was performed about the sheet|seat of the polarizing plate with a protective film in the state which peeled and removed the separator, and the result was made into the amount of secondary curl.

(production of polarizer)

A polyvinyl alcohol film with a thickness of 20 μm (the average degree of polymerization is about 2400, and the degree of saponification is more than 99.9 mol%) is uniaxially stretched about 5 times in the longitudinal direction by dry stretching, and then kept in a tensioned state. After immersing in water for 1 minute, it was immersed for 60 seconds in an aqueous solution at 28° C. whose weight ratio of iodine/potassium iodide/water was 0.05/5/100. Thereafter, it was immersed for 300 seconds in a 72° C. aqueous solution having a weight ratio of potassium iodide/boric acid/water of 8.5/8.5/100. Next, after washing with pure water at 26° C. for 20 seconds, drying treatment was performed at 65° C. to obtain a polarizing plate with a thickness of 7 μm in which iodine was adsorbed and aligned on the polyvinyl alcohol film.

(Manufacture of Brightness Improvement Film with Hard Coat)

A hard coat layer was formed on one surface of a 17 μm thick brightness improvement film (“Advanced Polarized Film, Version 4” manufactured by 3M Corporation) to obtain a 20 μm thick brightness improvement film with a hard coat layer.

(preparation of protective film)

The following 2 types of protective films are prepared:

Protective film A with a total thickness T2 of 93 μm; “LDM series” manufactured by LG Chem Co., Ltd. (composed of an acrylic second adhesive layer with a thickness of 18 μm and a resin containing polyethylene terephthalate with a thickness of 75 μm) membrane composition),

A protective film B with a total thickness T2 of 58 μm; “SAT-4238TF-JSL” manufactured by Sun-A-Kaken Co., Ltd. ethylene glycol ester resin film with a thickness of 38 μm).

(preparation of protective film)

A cyclic polyolefin-based resin film manufactured by Japan Zeon Co., Ltd. (thickness 13 μm, in-plane retardation value _Re = 0.8 nm at a wavelength of 590 nm, thickness direction retardation value R _th at a wavelength of 590 nm = 3.4 nm, The retardation value in the thickness direction R _th = 3.5 nm at a wavelength of 483 nm, and the retardation value in the thickness direction R _th = 2.8 nm at a wavelength of 755 nm).

(Preparation of the first adhesive layer)

As the first adhesive layer with a release film, a release-treated 38-μm-thick polyethylene terephthalate-containing release film was provided with a 20-μm-thick acrylic adhesive. Adhesive layer Commercially available adhesive layer with release film. The storage elastic modulus of this pressure-sensitive adhesive layer was 0.05 MPa at 23°C and 0.04 MPa at 80°C.

(Production of the third adhesive layer)

An organic solvent solution in which a urethane acrylate oligomer and an isocyanate-based crosslinking agent were added to a copolymer of butyl acrylate and acrylic acid was coated with a die coater so that the thickness after drying was 5 μm. The release-treated surface of the 38 μm-thick polyethylene terephthalate release film that had been subjected to release treatment was dried to obtain a third pressure-sensitive adhesive layer with a release film. The storage elastic modulus of this pressure-sensitive adhesive layer was 0.40 MPa at 23°C and 0.18 MPa at 80°C.

(Preparation of water-based adhesive)

A polyvinyl alcohol aqueous solution was prepared by dissolving 3 parts by weight of carboxy-modified polyvinyl alcohol ["KL-318" manufactured by Kuraray Corporation] with respect to 100 parts by weight of water. A water-soluble polyamide epoxy resin ["Sumirez Resin 650 (30)" manufactured by Taoka Chemical Industry Co., Ltd., solid content concentration 30% by weight] was mixed in the obtained aqueous solution at a ratio of 1.5 parts by weight relative to 100 parts by weight of water. , to obtain a water-based adhesive.

<Example 1>

A polarizing plate with a protective film having the same layer composition as in FIG. 4 was produced by the following procedure. First, the protective film prepared as the upper surface of the protective film 22 is bonded to one surface of the above-mentioned polarizing plate 10 using the above-mentioned water-based adhesive. Before bonding, corona treatment of 15.9 kJ/m ² was given to the bonding surface of the protective film 22 with the polarizing plate 10 . Thereafter, it was dried at 80° C. for 5 minutes, and aged at 40° C. for 168 hours.

Then, the above-mentioned first pressure-sensitive adhesive layer 31 (having a separator 70 on the outer surface) is bonded to the surface of the protective film 22 opposite to the polarizing plate 10 . Before bonding, both the bonding surface of the protective film 22 and the bonding surface of the 1st pressure-sensitive adhesive layer 31 were given the corona treatment of 15.9 kJ/m< ² >. Next, the above-mentioned third pressure-sensitive adhesive layer 32 (having a separator on the outer surface) is bonded to the surface of the polarizing plate 10 opposite to the protective film 22 . Before bonding, both the bonding surface of the polarizing plate 10 and the bonding surface of the 3rd pressure-sensitive adhesive layer were given the corona treatment of 15.9 kJ/m< ² >.

Then, after peeling and removing the separator of the third pressure-sensitive adhesive layer 32 , the aforementioned hard-coated brightness improvement film 50 is bonded to the surface of the third pressure-sensitive adhesive layer 32 exposed by peeling. Before bonding, the bonding surface of the brightness improvement film 50 was corona-treated at 15.9 kJ/m ² . The total thickness T1 of the polarizing plate 100 formed by the layer constitution of the first adhesive layer 31 /protective film 22 /polarizing plate 10 /third adhesive layer 32 /hard-coated brightness improvement film 50 was 66 μm.

Finally, this was bonded to the outer surface of the hard coat layer which the brightness improvement film 50 has via the 2nd adhesive layer of the said protective film A, and the polarizing plate with a protective film was obtained. A single body of 221 mm x 139 mm size was cut out from the obtained polarizing plate with a protective film, and the amount of curl was measured for the single body according to the above-mentioned method. The results are shown in Table 1.

<Example 2>

A polarizing plate with a protective film having the same layer configuration as that in FIG. 2 was produced by the following procedure except that the protective film 22 was omitted. First, the protective film prepared as the upper surface of the protective film 21 is bonded to one surface of the polarizing plate 10 using the above-mentioned water-based adhesive. Before lamination, corona treatment of 15.9 kJ/m ² was given to the lamination surface of the protective film 21 and the polarizing plate 10 . Thereafter, it was dried at 80° C. for 5 minutes, and aged at 40° C. for 168 hours.

Then, the above-mentioned first pressure-sensitive adhesive layer 31 (having a separator 70 on the outer surface) is bonded to the other surface of the polarizing plate 10 . Before bonding, both the bonding surface of the polarizing plate 10 and the bonding surface of the 1st adhesive layer 31 were given the corona treatment of 15.9 kJ/m< ² >. The total thickness T1 of the polarizing plate 100 formed by the layer constitution of the first adhesive layer 31 /polarizing plate 10 /protective film 21 was 40 μm.

Finally, this was bonded to the outer surface of the protective film 21 via the second adhesive layer of the above-mentioned protective film A to obtain a polarizing plate with a protective film. A single sheet was produced from the obtained polarizing plate with a protective film in the same manner as in Example 1, and the amount of curl was measured. The results are shown in Table 1.

<Example 3>

Except having used the above-mentioned protective film B instead of the protective film A, it carried out similarly to Example 1, the polarizing plate with a protective film, and its single body were produced, and the curl amount was measured. The results are shown in Table 1.

＜Comparative example 1＞

Except not having attached the protective film, it carried out similarly to Example 1, the polarizing plate and its single body were produced, and the amount of curl was measured. The results are shown in Table 1.

＜Comparative example 2＞

(1) Production of polarizers

A polyvinyl alcohol film with a thickness of 30 μm (the average degree of polymerization is about 2400, and the degree of saponification is more than 99.9 mol%) is stretched longitudinally and uniaxially to about 5 times by dry stretching, and then kept under tension in pure water at 60°C. After immersing for 1 minute, it was immersed for 60 seconds in an aqueous solution at 28° C. with a weight ratio of iodine/potassium iodide/water of 0.05/5/100. Thereafter, it was immersed for 300 seconds in a 72° C. aqueous solution having a weight ratio of potassium iodide/boric acid/water of 8.5/8.5/100. Next, after washing with pure water at 26° C. for 20 seconds, drying treatment was performed at 65° C. to obtain a polarizing plate with a thickness of 12 μm in which iodine was adsorbed and oriented on the polyvinyl alcohol film.

(2) Production of polarizing plate with protective film

A polarizing plate with a protective film having the same layer composition as in FIG. 2 was produced by the following procedure. First, a triacetyl cellulose film (trade name "KC2UAW" available from KonicaMinolta Co., Ltd., "KC2UAW", thick 25 μm), and a norbornene-based resin film (commercial name “ZEONOR” available from Zeon Co., Ltd., thickness 23 μm) as the protective film 22 . Before bonding, the corona treatment of 15.9 kJ/m< ² > was given to the bonding surface with the polarizing plate 10 of the protective films 21 and 22 . Then, it dried at 80 degreeC for 5 minutes, and aged at 40 degreeC for 168 hours.

Then, the above-mentioned first pressure-sensitive adhesive layer 31 (having a separator 70 on the outer surface) is bonded to the surface of the protective film 22 opposite to the polarizing plate 10 . Before bonding, both the bonding surface of the protective film 22 and the bonding surface of the 1st pressure-sensitive adhesive layer 31 were given the corona treatment of 15.9 kJ/m< ² >. The total thickness T1 of the polarizing plate 100 formed of the layer constitution of the first adhesive layer 31 /protective film 22 /polarizing plate 10 /protective film 21 was 80 μm. Finally, this was bonded to the outer surface of the protective film 21 via the second adhesive layer of the protective film B described above to obtain a polarizing plate with a protective film. A single sheet was produced from the obtained polarizing plate with a protective film in the same manner as in Example 1, and the amount of curl was measured. The results are shown in Table 1.

＜Comparative example 3＞

Using the following procedure, a polarizing plate with a protective film was produced. First, an adhesive layer (having a separator on the outer surface) was bonded to one surface of the polarizing plate 10 produced in (1) of Comparative Example 2 above. This adhesive layer is the same as the third adhesive layer described above. Before bonding, corona treatment of 15.9 kJ/m ² was given to the bonding surface of the adhesive layer. The total thickness T1 of the polarizing plate 100 formed from the layer constitution of the adhesive layer/polarizing plate 10 was 17 μm. Finally, this was bonded to the outer surface of the polarizing plate 10 through the second adhesive layer of the above-mentioned protective film A to obtain a polarizing plate with a protective film. A single sheet was produced from the obtained polarizing plate with a protective film in the same manner as in Example 1, and the amount of curl was measured. The results are shown in Table 1.

[Table 1]

Claims (7)

1. with a polarization plates for protecting film,

The protecting film of the polarization plates possessing the thickness T1 comprising polaroid and the thickness T2 being laminated in one surface,

The thickness of described polaroid is less than 15 μm,

Another surface of described polarization plates is made up of the surface of the first adhesive phase,

Described protecting film is made up of the second adhesive phase being laminated in one surface and the resin molding being laminated in monolayer thereon,

Thickness ratio is in the scope that T2/T1 is 0.8～4,

The unit of described thickness T1 and described thickness T2 is μm.

2. the polarization plates with protecting film according to claim 1, wherein,

It is also equipped with being laminated in the isolating membrane on another surface of described polarization plates.

3. the polarization plates with protecting film according to claim 1, wherein,

The thickness T2 of described protecting film is more than 60 μm.

4. the polarization plates with protecting film according to claim 1, wherein,

Described polarization plates also comprises the blooming beyond described polaroid,

At protecting film described in the surface stacking of described blooming.

5. the polarization plates with protecting film according to claim 4, wherein,

Described blooming is that brightness improves film.

6. the polarization plates with protecting film according to claim 1, wherein,

Described resin molding comprises polyester based resin.

7. a duplexer, it comprises image-displaying member and is laminated in the polarization plates with protecting film according to any one of claim 1～6 thereon.