JP2020095287A - Laminate body - Google Patents

Abstract

To provide a laminate body in which a surface protective film is laminated on one surface of a polarizer, a separation film is laminated on another surface of the polarizer, the polarizer includes a polarizing device, the surface protective film in a deflecting state has its largest force F3 (N) and strain S3 (mm) when a piercing tool is dropped vertically, the product (K3) of the force and the strain is at least 1.00 N mm, and the separation film does not cause separation failures.SOLUTION: In the laminate body, a layer made in a deflection state of the polarizer and the surface protective film has its largest force F1 (N) and strain S1 (mm) when a piercing tool is dropped vertically to the layer, and the product (K1) of the force and the strain is at least 3.70 N mm. The product (K2) of the force F2 (N) and the strain S2 (mm) of the polarizer in a deflection state may be 1.00 N mm at a maximum.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminate, specifically, a surface protective film is releasably laminated on one surface of a polarizing plate including a polarizer, and a release film is releasably laminated on the other surface via an adhesive layer. Regarding the laminated body.

The polarizing plate is widely used in image display devices such as liquid crystal display devices and organic electroluminescence (EL) display devices, and particularly in recent years in various mobile devices such as smartphones.
Conventionally, a polarizing plate includes a polarizing plate, specifically, one obtained by laminating a protective film on one or both sides of a polarizer in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, for example. Is used.

Such a polarizing plate is a laminate in which a peelable surface protective film (also called a protect film) and a peeling film (also called a separate film) for preventing stains and scratches on the surface are attached to the surface. It is generally marketed as.

When the polarizing plate is attached to a display element such as a liquid crystal cell or an organic EL element, the release film attached to the surface is peeled off, and the polarizing plate is attached to the display element via the exposed adhesive layer. To meet. When the release film is peeled off, as shown in Patent Document 1 [JP-A-6-48633], a laminate (a surface protective film is laminated on one surface of a polarizing plate and a release film is formed on the other surface). The surface protective film side of the laminated film) is fixed to a holding table by a method such as suction and adsorption, and a release tape is attached to the release film. Then, the release tape is pulled to remove the release film from the surface of the polarizing plate. At this time, since the phenomenon that the polarizing plate comes off from the surface protection film can be suppressed, a surface protection film having relatively low rigidity, specifically, the maximum force (F(F( N)) and the strain (S (mm)), which has a rigidity K3 of 1.00 N·mm or less is preferable.

However, in the conventional laminated body, when the release film is peeled off, the polarizing plate and the surface protection film that have been fixed follow the movement of the release film and lifted from the holding table, and the fixation of the polarizing plate and the surface protection film is released. Therefore, there is a problem that the release film cannot be easily peeled off. In recent years, the thickness of the polarizing plate has become thin, the polarizing plate has lost its rigidity, and its rigidity is relatively low, and peeling defects are more likely to occur.

This problem can be solved by increasing the force such as a suction force or a suction force when fixing the laminated body, or by reducing the adhesive force of the release film, but on the other hand, there is a new problem. Will occur. That is, when the force acting on the laminated body such as the force of attracting or the force of attracting becomes large, traces remain on the polarizing plate and the appearance deteriorates. Further, when the adhesive force of the release film is reduced, a gap is created between the release film and the polarizing plate when the laminated body is subjected to an impact due to transportation or the like.

JP-A-6-48633

An object of the present invention is to provide a laminate that does not cause peeling defects of the release film.

[1] A surface protective film is releasably laminated on one surface of the polarizing plate,
A release film is releasably laminated on the other surface of the polarizing plate via an adhesive layer,
The polarizing plate includes a polarizer,
When the surface protection film is used as a measurement film and the maximum force (F(N)) measured by the following measurement method is F3 and the strain (S(mm)) is S3, the maximum force F3(N) And a strain S3 (mm) (F3 (N) x S3 (mm)) has a rigidity K3 of 1.00 N·mm or less,
When a layer composed of the polarizing plate and the surface protective film is used as a measuring film, the maximum force (F(N)) measured by the following measuring method is F1, and the strain (S(mm)) is S1. And the rigidity K1 expressed as the product (F1(N)×S1(mm)) of the maximum force F1(N) and the strain S1(mm) is 3.70 N·mm or more and 10.0 N·mm or less. A stack.

Measuring method:
It has a circular through hole in the center when viewed from the top surface, the diameter of the through hole on the top surface is 30 mm, and the shape of the through hole viewed from the side surface is a shape composed of a columnar lower part and a hemispherical upper part. On the measuring table,
Place a rectangular measuring film of 25 mm x 43 mm,
From above the measuring film, a needle having a spherical tip, a tip diameter of 1 mmφ and a radius of curvature of 0.5 mm was placed at 1.0 cm/sec so that the needle would pass through the center of the through hole of the measuring table. Vertically at the speed of
After the tip of the needle comes into contact with the film for measurement, the maximum load for maintaining the bent state of the film is measured as the maximum force F(N), and the strain S (mm) of the film at that time is measured.

[2] Maximum force F2 when the maximum force (F(N)) measured by the measurement method using the polarizing plate as a measurement film is F2(N) and the strain (S(mm)) is S2. The laminate according to [1], which has a rigidity K2 represented as a product of (N) and strain S2 (mm) of 1.00 N·mm or less.

[3] The laminate according to claim 1 or 2, wherein the adhesive force between the polarizing plate and the release film is 0.02 to 0.05 N/25 mm.

[4] A step of fixing the surface protective film in the laminate according to any one of [1] to [3] on a holding table with an adhesive force of 0.1 to 0.3 N/60 mm,
A method for producing a polarizing plate with a surface protective film, which comprises a step of peeling a release film from the laminate.

ADVANTAGE OF THE INVENTION According to this invention, the laminated body which the peeling defect of a peeling film does not produce can be provided.

It is a schematic sectional drawing which shows an example of the laminated constitution which the laminated body of this invention has. It is a schematic sectional drawing which shows an example of the laminated constitution which the laminated body of this invention has. FIG. 3 is a schematic view showing an apparatus for measuring the maximum force F and the strain S in a state where the film is warped. It is a figure for demonstrating the maximum force F and distortion S in the state where the film was bent. 6 is an image showing an example of a state in which a film is folded.

<Laminate>
In the laminate, the surface protective film is laminated on one surface of the polarizing plate, and the release film is laminated on the other surface of the polarizing plate. The polarizing plate has at least a polarizer. Hereinafter, an example of the layer structure of the laminate of the present invention will be described with reference to the drawings. The polarizing plate may include a protective film, a retardation layer, a brightness enhancement film and the like in addition to the polarizer. Further, the polarizing plate may include a pressure-sensitive adhesive layer for adhering the polarizer, the retardation layer, the brightness enhancement film and the like to each other.

FIG. 1 is a schematic sectional view showing an example of the laminated body of the present invention. The laminated body 100 shown in FIG. 1A is composed of a surface protective film 30 laminated on one surface of the polarizing plate 10 and a release film 20 laminated on the other surface of the polarizing plate 10. The surface protection film 30 is composed of a base film 31 and an adhesive layer 32 laminated on the base film 31. The surface protection film 30 can be peeled from the polarizing plate 10 in a state where the base film 31 and the pressure-sensitive adhesive layer 32 are laminated. In the polarizing plate 10, a protective film 12 is laminated on one surface of a polarizer 11 via an adhesive layer (not shown), and a brightness enhancement film 14 is laminated on the other surface via an adhesive layer 16 for protection. It has a layer structure in which the pressure-sensitive adhesive layer 15 is laminated on the film 12. The surface protection film 30 is laminated on the brightness enhancement film 14. A release film 20 is laminated on the adhesive layer 15. The release film 20 can be released from the polarizing plate 10 with the adhesive layer 15 remaining.

The laminate 101 shown in FIG. 1B is composed of a surface protective film 30 laminated on one surface of the polarizing plate 10 and a release film 20 laminated on the other surface of the polarizing plate 10. The surface protection film 30 is composed of a base film 31 and an adhesive layer 32 laminated on the base film 31. The surface protection film 30 can be peeled from the polarizing plate 10 in a state where the base film 31 and the pressure-sensitive adhesive layer 32 are laminated. In the polarizing plate 10, the protective film 12 is laminated on one surface of the polarizer 11 via an adhesive layer not shown, and the protective film 13 is laminated on the other surface via an adhesive layer not shown, The pressure-sensitive adhesive layer 15 is laminated on the protective film 12, and the brightness enhancement film 14 is laminated on the protective film 13 via the pressure-sensitive adhesive layer 16. The surface protection film 30 is laminated on the brightness enhancement film 14. A release film 20 is laminated on the adhesive layer 15. The release film 20 can be released from the polarizing plate 10 with the adhesive layer 15 left.

The laminated body 102 shown in FIG. 2A includes a surface protective film 30 laminated on one surface of the polarizing plate 10 and a release film 20 laminated on the other surface of the polarizing plate 10. The surface protection film 30 is composed of a base film 31 and an adhesive layer 32 laminated on the base film 31. The surface protection film 30 can be peeled from the polarizing plate 10 in a state where the base film 31 and the pressure-sensitive adhesive layer 32 are laminated. In the polarizing plate 10, the protective film 12 is laminated on one surface of the polarizer 11 via an adhesive layer not shown, and the protective film 13 is laminated on the other surface via an adhesive layer not shown, The retardation layer 17 is laminated on the protective film 12 via an adhesive layer or a pressure-sensitive adhesive layer (not shown), and the pressure-sensitive adhesive layer 15 is laminated on the retardation layer 17. A release film 20 is laminated on the pressure-sensitive adhesive layer 15. This release film can be released from the polarizing plate 10 leaving the adhesive layer 15.

The laminated body 103 shown in FIG. 2B is composed of a surface protective film 30 laminated on one surface of the polarizing plate 10 and a release film 20 laminated on the other surface of the polarizing plate 10. The surface protection film 30 is composed of a base film 31 and a pressure-sensitive adhesive layer 32 laminated thereon. The surface protection film 30 can be peeled from the polarizing plate 10 in a state where the base film 31 and the pressure-sensitive adhesive layer 32 are laminated. In the polarizing plate 10, the retardation layer 17 is laminated on one surface of the polarizer 11 via an adhesive layer or an adhesive layer not shown, and the protective film is provided on the other surface via an adhesive layer not shown. 13 is laminated, and the pressure-sensitive adhesive layer 15 is laminated on the retardation layer 17. A release film 20 is laminated on the pressure-sensitive adhesive layer 15. The release film 20 can be released from the polarizing plate 10 with the adhesive layer 15 remaining.

In the laminates 100 to 103, the surface protective film 30 and the release film 20 are preferably members that form the outermost surface of the laminate. The laminates 100 to 103, the polarizing plate 10, the release film 20, and the surface protection film 30 may have layers other than the illustrated layers.

In the layered product of the present embodiment, the layer composed of the polarizing plate and the surface protection film has a maximum force F1 (N) and a strain S1 (mm) measured by the above-described measuring method, that is, puncture the layer. When the jig is vertically lowered, the product of the maximum force F1(N) and the strain S1(mm) in the bent state is 3.70 N·mm or more. The product (K1) of the maximum force F1 (N) and the strain S1 (mm) in the flexed state is preferably 4.5 N·mm or more, and more preferably 5.0 N·mm or more, Usually, it is 10.0 N·mm or less, preferably 9.0 N·mm or less. In order to set the range of the product (K1) of the force F1(N) and the strain S1(mm), it is preferable to select and combine the surface protection film and the polarizing plate, for example. When a surface protection film having a relatively large product (K3) of the maximum force F3(N) and strain S3(mm), that is, a surface protection film having high rigidity is used as the surface protection film, the above F1(N) and S1 are used. The product (K1) with (mm) becomes large. Examples of such a surface protective film include a thick surface protective film and a surface protective film made of a hard resin. Further, even if a polarizing plate having high rigidity is used, the product (K1) of F1 (N) and S1 (mm) becomes large.

F1(N) can be 1.0 N or more and 3.0 N or less, and may be 1.5 N or more and 3.0 N or less. S1 (mm) can be 1.5 mm or more and 5.0 mm or less, and may be 2.0 mm or more and 4.0 mm or less.

The product of the maximum force F1 (N) and the strain S1 (mm) in the flexed state can be measured using, for example, a compression tester KES-G5 manufactured by Kato Tech Co., Ltd.
This will be specifically described with reference to FIGS. 3, 4 and 5.

Here, a method for measuring the maximum force [F(N)] and [strain S(mm)] of the film (measuring film) to be measured in a bent state will be described. When the measuring film is a layer composed of a polarizing plate and a surface protective film, F1 and S1 are measured. When the measuring film is a polarizing plate, F2 and S2 are measured. When the measuring film is a surface protective film, F3 and S3 are measured.

First, the measurement film 3 to be measured is placed on the table 2 which is a measurement table. The measuring film 3 is a layer composed of a polarizing plate and a surface protective film, a polarizing plate alone, or a surface protective film alone. It is not necessary to provide a fixing jig on the film 3 to be measured. The base 2 has a circular void (through hole) in the center when viewed from the upper surface, and the diameter of the void on the upper surface (double-headed arrow 44) is 30 mm. The shape of the void seen from the side surface is, for example, a shape composed of a columnar lower portion and a hemispherical upper portion (bell shape), a cone shape (cone shape, conical shape), or the like that becomes narrower toward the tip ( Taper shape). The size of the measurement film 3 to be measured is a rectangle of 25 mm (double arrow 43)×43 mm (double arrow 42).

Next, the piercing jig 1 is vertically lowered from above the placed film 3. At this time, the piercing jig 1 passes through the center of the circular void. The piercing jig 1 uses a needle having a spherical tip, a tip diameter of 1 mmφ, and a curvature of 0.5R (curvature radius 0.5 mm). The speed at which the piercing jig 1 is lowered is 1.0 cm/sec.

After the tip of the piercing jig (needle) 1 comes into contact with the measuring film 3, the maximum load (N) and strain (mm) that maintain the bent state of the film 3 are measured. That is, when the piercing jig 1 is lowered onto the measuring film 3, wrinkles and folds occur in the measuring film 3 (for example, the folds shown in FIG. 4B and FIG. 5). Then, the load and strain (length of the double-headed arrow 40) immediately before that are measured. The flexed state of the measuring film 3 refers to a state in which the film 3 has a bow shape (for example, an arc shape, an elliptic arc shape, an arc shape such as a catenary shape) when viewed from the side (FIG. 4A).

In the laminated body of the present embodiment, when the piercing jig is vertically lowered with respect to the polarizing plate alone, the product (K2) of the maximum force F2 (N) and the strain S2 (mm) in the bent state is obtained. ) May be 1.00 N·mm or less, or 0.70 N·mm or less. In this case, when the piercing jig is vertically lowered with respect to the surface protection film alone, the product (K3) of the maximum force F3 (N) and the strain S3 (mm) in the bent state is 0. When it is 0.50 mm·mm or more, peeling failure of the release film hardly occurs, which is preferable. When the product of the maximum force F2(N) and the strain S2(mm) is 0.30 N·mm or less, the product of the maximum force F3(N) and the strain S3(mm) is 0. Similarly, it is preferably 30 N·mm or more. When the product of the maximum force F2(N) and the strain S2(mm) is 0.20 N·mm or less, the product of the maximum force F3(N) and the strain S3(mm) is 0. Similarly, it is preferably 50 N·mm or more. Even when using a polarizing plate having low rigidity, it is possible to reduce peeling defects of the peeling film by selecting a surface protective film having high rigidity accordingly. With such a combination, peeling failure of the release film is unlikely to occur even when the laminate includes a polarizing plate having low rigidity.

The laminate may be obtained by producing a long laminate by roll-to-roll while transporting each member constituting the laminate, and cutting the laminate to obtain a member having a predetermined shape. It may be obtained by preparing each and sequentially stacking.

The shape of the laminate is not particularly limited, but may be a polygon such as a rectangle or a triangle, a circle, an ellipse, or a combination thereof.

When the laminate has a rectangular shape having a long side and a short side, the length of the long side is preferably 35 to 5 cm, more preferably 25 to 10 cm, and the length of the short side is 25 to. It is preferably 5 cm, more preferably 20 to 6 cm. By setting the size in such a range, the releasability can be further improved.

Hereinafter, each member included in the laminated body will be described.
<Polarizing plate>
The polarizing plate has a product (K2) of the maximum force F2 (N) and the strain S2 (mm) when the piercing jig is vertically lowered with respect to the polarizing plate alone. It is 0.10 N·mm or more, preferably 0.15 N·mm or more, more preferably 0.20 N·mm or more, and further preferably 0.30 N·mm or more. The product (K2) of the maximum force F2 (N) and the strain S2 (mm) may be 1.00 N·mm or less, or 0.70 N·mm or less. Even if the product K2 is 1.00 N·mm or less, the release film can be peeled off without causing peeling failure in the laminate of the present invention. The product (K2) of the maximum force F2(N) and the strain S2(mm) can be obtained by the same method as the method of obtaining the product of the maximum force F1(N) and the strain S1(mm) described above. ..

F2(N) can be 0.20N or more and 1.0N or less, and may be 0.3N or more and 0.8N or less. S2 (mm) can be 0.5 mm or more and 3.0 mm or less, and may be 1.0 mm or more and 2.0 mm or less.

The product of the maximum force F2 (N) and the strain S2 (mm) (when the polarizing plate is provided with a protective film only on one surface of the polarizer and when the polarizing plate is provided with at least one of the brightness enhancement films) ( K2) tends to be small. Further, the stretching ratio and stretching temperature of the polarizer can also affect the magnitude of the product of the maximum force F2(N) and the strain S2(mm). For example, when the stretch ratio of the polarizer is increased, the product (K2) of the maximum force F2 (N) and the strain S2 (mm) tends to be small, and when the stretch ratio of the polarizer is decreased, the product (K2 ) Tends to be large.

The polarizing plate 10 is a polarizing element including at least a polarizer, and usually further includes a thermoplastic resin film laminated on one side or both sides thereof. The thermoplastic resin film can be a protective film that protects the polarizer, another film having an optical function, or the like. The thermoplastic resin film has at least a resin layer (for example, a hard coat layer, an antistatic layer, an antiglare layer, a light diffusion layer, an antireflection layer, a low refractive index layer, an antifouling layer, or the like) laminated on the surface thereof. A kind of optical layer) may be provided. The thermoplastic resin film can be attached to the polarizer via the adhesive layer. The surface protection film 30 may be laminated on the surface of this resin layer.

The effect of the present invention is remarkable when the laminate further includes a brightness enhancement film or a retardation layer. A polarizing plate including a brightness enhancement film or the like has low rigidity and is likely to cause peeling failure. According to the present invention, the occurrence of peeling defects can be reduced even when the laminate includes a brightness enhancement film or the like.

The thickness (μm) of the polarizing plate is usually 150 μm or less, and the effect of the present invention is remarkable when the rigidity is 75 μm or less, and further 70 μm or less. The thickness of the polarizing plate 10 is preferably 30 μm or more, more preferably 50 μm or more.

(1) Polarizer The polarizer that constitutes the polarizing plate 10 absorbs linearly polarized light having an oscillating plane parallel to its absorption axis, and linearly polarized light having an oscillating plane orthogonal to the absorption axis (parallel to the transmission axis). An absorption type polarizer having a property of transmitting light, and a uniaxially stretched polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and oriented can be suitably used. The polarizer is, for example, a step of uniaxially stretching a polyvinyl alcohol resin film; a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol resin film with a dichroic dye; It can be produced by a method including a step of treating the alcohol-based resin film with a cross-linking solution such as a boric acid aqueous solution; and a step of washing with water after the treatment with the cross-linking solution.

As the polyvinyl alcohol resin, saponified polyvinyl acetate resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers with other monomers copolymerizable with vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

In the present specification, “(meth)acrylic” means at least one selected from acrylic and methacrylic. The same applies to “(meth)acryloyl”, “(meth)acrylate” and the like.

The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and 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 1000 to 10000, preferably 1500 to 5000. The average degree of polymerization of the polyvinyl alcohol resin can be determined according to JIS K 6726.

A film formed from such a polyvinyl alcohol-based resin is used as a raw film of a polarizer (polarizer). The method for forming the polyvinyl alcohol-based resin is not particularly limited, and a known method is adopted. The thickness of the polyvinyl alcohol-based raw film is not particularly limited, but in order to make the thickness of the polarizer 15 μm or less, it is preferable to use a film having a thickness of 5 to 35 μm. More preferably, it is 20 μm or less.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before the dyeing of the dichroic dye, simultaneously with the dyeing, or after the dyeing. When the uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before or during the crosslinking treatment. In addition, uniaxial stretching may be performed at these plural stages.

In the uniaxial stretching, stretching may be uniaxial between rolls having different peripheral speeds, or uniaxial stretching may be performed using a heat roll. The uniaxial stretching may be dry stretching in which the stretching is performed in the atmosphere, or wet stretching in which the polyvinyl alcohol-based resin film is swollen with a solvent or water. The draw ratio is usually 3 to 8 times.

As a method for dyeing a polyvinyl alcohol resin film with a dichroic dye, for example, a method of immersing the film in an aqueous solution containing the dichroic dye is adopted. As the dichroic pigment, iodine or a dichroic organic dye is used. The polyvinyl alcohol resin film is preferably immersed in water before the dyeing treatment.

As the crosslinking treatment after dyeing with a dichroic dye, a method of immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution is usually employed. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide.

The thickness of the polarizer is usually 30 μm or less, preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less. In particular, setting the thickness of the polarizer to 15 μm or less is advantageous for thinning the laminated body. The thickness of the polarizer is usually 2 μm or more, and preferably 3 μm or more from the viewpoint of imparting rigidity to the polarizing plate.

As the polarizer, for example, as described in JP-A-2016-170368, one in which a dichroic dye is oriented in a cured film obtained by polymerizing a liquid crystal compound may be used. As the dichroic dye, those having absorption in the wavelength range of 380 to 800 nm can be used, and organic dyes are preferably used. Examples of dichroic dyes include azo compounds.
The liquid crystal compound is a liquid crystal compound that can be polymerized while being aligned, and can have a polymerizable group in its molecule.

(2) Protective Film The protective film that can be laminated on one side or both sides of the polarizer is a translucent (preferably optically transparent) thermoplastic resin, for example, a chain polyolefin resin (polypropylene resin). Etc.), polyolefin resins such as cyclic polyolefin resins (norbornene resins, etc.); cellulose resins such as triacetyl cellulose and diacetyl cellulose; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polycarbonate resins; (Meth)acrylic resin such as methyl methacrylate resin; polystyrene resin; polyvinyl chloride resin; acrylonitrile butadiene styrene resin; acrylonitrile styrene resin; polyvinyl acetate resin; polyvinylidene chloride resin Polyamide-based resin; polyacetal-based resin; modified polyphenylene ether-based resin; polysulfone-based resin; polyether sulfone-based resin; polyarylate-based resin; polyamide-imide-based resin; polyimide-based resin and the like.

As the chain polyolefin resin, polyethylene resin (polyethylene resin which is a homopolymer of ethylene or a copolymer mainly composed of ethylene), polypropylene resin (a polypropylene resin which is a homopolymer of propylene or propylene is mainly used) In addition to a chain olefin homopolymer such as a copolymer), a copolymer composed of two or more kinds of chain olefins can be mentioned.

Cyclic polyolefin resin is a general term for resins polymerized with cyclic olefin as a polymerized unit, and is described in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137 and the like. Resins. Specific examples of cyclic polyolefin resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins with chain olefins such as ethylene and propylene (typically Are random copolymers), graft polymers obtained by modifying these with unsaturated carboxylic acids or their derivatives, and their hydrides. Among them, norbornene-based resins using norbornene-based monomers such as norbornene and polycyclic norbornene-based monomers as the cyclic olefin are preferably used.

The polyester-based resin is a resin having an ester bond other than the following cellulose ester-based resin, and is generally composed of a polycondensate of a polyvalent carboxylic acid or its derivative and a polyhydric alcohol. As the polyvalent carboxylic acid or its derivative, a divalent dicarboxylic acid or its derivative can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. A divalent diol can be used as the polyhydric alcohol, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. A typical example of the polyester resin is polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol.

The (meth)acrylic resin is a resin containing a compound having a (meth)acryloyl group as a main constituent monomer. Specific examples of the (meth)acrylic resin include, for example, poly(meth)acrylic acid ester such as polymethylmethacrylate; methylmethacrylate-(meth)acrylic acid copolymer; methylmethacrylate-(meth)acrylic acid. Ester copolymer; methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymer; methyl (meth)acrylate-styrene copolymer (MS resin etc.); methyl methacrylate and alicyclic hydrocarbon group It includes a copolymer with a compound having (for example, a methyl methacrylate-cyclohexyl methacrylate copolymer, a methyl methacrylate-norbornyl (meth)acrylate copolymer, etc.). Preferably, a polymer containing poly(meth)acrylic acid C _1-6 alkyl ester as a main component such as methyl poly(meth)acrylate is used, and more preferably, methyl methacrylate is the main component (50 to 100). % By weight, preferably 70 to 100% by weight) is used.

The cellulose ester-based resin is an ester of cellulose and fatty acid. Specific examples of the cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Moreover, these copolymers and those in which a part of the hydroxyl groups are modified with other substituents are also included. Among these, cellulose triacetate (triacetyl cellulose) is particularly preferable.

Polycarbonate resin is an engineering plastic made of a polymer in which monomer units are bonded via a carbonate group.

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

For example, depending on the mode of the liquid crystal display device, the protective film may be stretched and/or shrunk to give a suitable retardation value. For example, a retardation layer (or film) having a single layer or a multilayer structure can be used as the protective film for the purpose of viewing angle compensation. In this case, the polarizing plate 10 can be an elliptical polarizing plate or a circular polarizing plate including a laminated structure of a polarizer and a retardation layer, or a polarizing plate including a retardation layer and having a viewing angle compensation function.

The thickness of the protective film is usually 1 to 100 μm, but from the viewpoint of strength and handleability, it is preferably 5 to 60 μm, more preferably 10 to 55 μm, and further preferably 15 to 40 μm. If a protective film having a thickness within this range is used as the protective film constituting the polarizing plate, the product (K2) of F2 (N) and S2 (mm) of the polarizing plate itself including the protective film, and It is easy to adjust the product (K1) of F1 (N) and S1 (mm) of the layer composed of the plate and the surface protection film. Specifically, when a protective film having a thick thickness within the above range is used as the protective film, the product (K2) or the product (K1) tends to increase, and when the thickness falls within the above range, the product (K2) tends to increase. The product (K1) is small and there is a tendency to sleep. Further, when the thickness of the protective film is within this range, the polarizer is mechanically protected and the polarizer does not shrink even when exposed to a humid heat environment, and stable optical characteristics can be maintained.

Further, by selecting a material having high rigidity as the material forming the protective film, the product (K1) of F1(N) and S1(mm) and the product (K2 of F2(N) and S2(mm)) are selected. ) Can be adjusted. If a material having high rigidity is used as the material for the protective film, the product (K1) of F1(N) and S1(mm) and the product (K2) of F2(N) and S2(mm) are large. Tends to become. If a material having low rigidity is used as the material forming the protective film, the product (K1) of F1 (N) and S1 (mm) and the product (K2) of F2 (N) and S2 (mm) are small. Tends to become.

When protective films are attached to both surfaces of the polarizer, these protective films may be composed of the same kind of thermoplastic resin or different kinds of thermoplastic resins. The thickness may be the same or different. Furthermore, they may have the same phase difference characteristic or different phase difference characteristics.

As described above, at least one of the protective films has a hard coat layer, an antiglare layer, a light diffusing layer, an antireflection layer, a low refractive index layer, an electrostatic charge on its outer surface (the surface opposite to the polarizer). It may be provided with a surface treatment layer (coating layer) such as an antifouling layer and an antifouling layer. The thickness of the protective film includes the thickness of the surface treatment layer.

From the viewpoint of suppressing the inclusion of air bubbles between the surface protective film and the polarizing plate, the surface of the polarizing plate 10 on the surface protective film 30 side (the surface to which the surface protective film 30 is bonded and the surface treatment layer). May have a small arithmetic average roughness Ra according to JIS B 0601:2013. Specifically, Ra on the surface is preferably 0.3 μm or less, more preferably 0.2 μm or less, and further preferably 0.15 μm or less. Ra of the surface is usually 0.001 μm or more, for example 0.005 μm or more.

The protective film can be attached to the polarizer, for example, via an adhesive layer. As the adhesive forming the adhesive layer, a water-based adhesive, an active energy ray-curable adhesive or a thermosetting adhesive can be used, and 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 and a water-based two-component urethane-based emulsion adhesive. Above all, a water-based adhesive composed of a polyvinyl alcohol-based resin aqueous solution is preferably used. Examples of the polyvinyl alcohol-based resin include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of vinyl acetate and other monomers copolymerizable therewith. A polyvinyl alcohol-based copolymer obtained by saponifying a polymer, a modified polyvinyl alcohol-based polymer obtained by partially modifying a hydroxyl group thereof, or the like can be used. The water-based adhesive may contain a crosslinking agent such as an aldehyde compound (glyoxal or the like), an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, a polyvalent metal salt or the like.

When a water-based adhesive is used, it is preferable to carry out a drying step for removing water contained in the water-based adhesive after the polarizer and the protective film are bonded together. After the drying step, a curing step of curing at a temperature of 20 to 45° C., for example, may be provided.

The active energy ray-curable adhesive is an adhesive containing a curable compound that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, and is preferably an ultraviolet ray curable adhesive agent. Is.

The curable compound may be a cationically polymerizable curable compound or a radically polymerizable curable compound. Examples of the cationically polymerizable curable compound include epoxy compounds (compounds having one or more epoxy groups in the molecule) and oxetane compounds (one or more oxetane rings in the molecule). Or a combination thereof. Examples of the radical-polymerizable curable compound include a (meth)acrylic compound (compound having one or more (meth)acryloyloxy groups in the molecule) and a radical-polymerizable double bond. Other vinyl compounds or combinations thereof may be mentioned. You may use together a cationically polymerizable curable compound and a radically polymerizable curable compound. The active energy ray-curable adhesive usually further contains a cationic polymerization initiator and/or a radical polymerization initiator for initiating a curing reaction of the curable compound.

When laminating the polarizer and the protective film, a surface activation treatment may be performed on at least one of the laminating surfaces in order to enhance the adhesiveness. As surface activation treatment, dry treatment such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, ionizing actinic ray treatment (ultraviolet treatment, electron beam treatment, etc.) Ultrasonic treatment using a solvent such as water or acetone, saponification treatment, and wet treatment such as anchor coating treatment can be mentioned. These surface activation treatments may be performed alone or in combination of two or more.

When protective films are laminated on both sides of the polarizer, the adhesive for laminating these protective films may be the same kind of adhesive or different kinds of adhesive.

(3) Other Films The polarizing plate 10 can include films other than the polarizer and the protective film, and representative examples thereof are a brightness enhancement film and a retardation layer. When the polarizing plate 10 includes another film, the surface protection film 30 may be laminated on the surface of this film or the surface of the surface treatment layer laminated on this film.

The brightness enhancement film is also called a reflection-type polarizer, and a polarization conversion element having a function of separating emitted light from a light source (backlight) into transmitted polarized light and reflected polarized light or scattered polarized light is used. By arranging the brightness enhancement film on the polarizer, it is possible to improve the emission efficiency of the linearly polarized light emitted from the polarizer by utilizing the reflected light that is the reflected polarized light or the scattered polarized light. The brightness enhancement film can be laminated on the polarizer via an adhesive layer.
Another film such as a protective film may be interposed between the polarizer and the brightness enhancement film.

The brightness enhancement film can be, for example, an anisotropic reflective polarizer. An example of the anisotropic reflection polarizer is an anisotropic multiple thin film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction, and a specific example thereof is “APF” manufactured by 3M Company. Is. Another example of the anisotropic reflection polarizer is a composite of a cholesteric liquid crystal layer and a λ/4 plate, and a specific example thereof is "PCF" manufactured by Nitto Denko Corporation. Still another example of the anisotropic reflection polarizer is a reflection grid polarizer, and a specific example thereof is a metal grating reflection polarizer or metal fine particles that emits reflection polarized light even in the visible light region by performing fine processing on metal. Is a film stretched by adding to a polymer matrix.

As described above, a hard coat layer, an antiglare layer, a light diffusion layer, a retardation layer (such as a retardation layer having a retardation value of 1/4 wavelength), an antireflection layer, a low refraction layer on the outer surface of the brightness enhancement film. A surface treatment layer (coating layer) such as a coating layer, an antistatic layer, and an antifouling layer may be provided. By forming such a layer, the adhesion with the backlight tape and the uniformity of the displayed image can be improved. The thickness of the brightness enhancement film 50 is usually 10 to 100 μm, preferably 10 to 50 μm, more preferably 10 to 30 μm.

Examples of the retardation layer include a ¼ wavelength (λ/4) plate, a ½ wavelength (λ/2) plate, and a positive C plate. The λ/4 plate is a layer in which the in-plane retardation value Re(550) at the wavelength of 550 [nm] satisfies the relationship of 100 nm≦Re(550)≦200 nm. The λ/4 plate may exhibit reverse wavelength dispersion satisfying Re(450)<Re(550)<Re(650). The λ/2 plate is a layer satisfying Re(550) of 210 nm≦Re(550)≦300 nm. The positive C plate satisfies the relationship of Nz>Nx≧Ny, and the retardation value Rth(λ) in the thickness direction at the wavelength λ[nm] satisfies the relationship of −300 nm≦Rth(550)≦−20 nm. Preferably.

The retardation layer can be formed, for example, from the resins exemplified as the material of the protective film, and among them, a cyclic olefin resin and a styrene resin are preferable. The retardation layer may be formed of a single layer or a plurality of layers. The retardation layer having a plurality of layers includes, for example, a resin film (base film) exemplified as a material for the protective film and a layer in which a liquid crystal compound obtained by polymerizing a liquid crystal compound is cured, a plurality (for example, two layers). The liquid crystal compound of 1) may include a cured layer. The layer having a retardation can be a layer obtained by curing a resin film and/or a liquid crystal compound. The resin film can also serve as the protective film.

The retardation layer may be composed of one type of retardation layer or a plurality of types of retardation layers. When the retardation layer is composed of a plurality of retardation layers, a combination of a quarter wave plate and a half wave plate, and a combination of a quarter wave plate and a positive C plate are preferable.

The retardation layer preferably includes a layer in which the liquid crystal compound is cured. When the retardation layer is composed of a plurality of layers, any retardation layer may include the layer in which the liquid crystal compound is cured. The type of liquid crystal compound is not particularly limited, but it can be classified into a rod-shaped type (rod-shaped liquid crystal compound) and a disc-shaped type (disc-shaped liquid crystal compound, discotic liquid crystal compound) depending on its shape. Further, there are low molecular type and high molecular type respectively. The term "polymer" generally means a polymer having a degree of polymerization of 100 or more (polymer physics/phase transition dynamics, Masao Doi, page 2, Iwanami Shoten, 1992). In this embodiment, any liquid crystal compound can be used. Furthermore, two or more rod-shaped liquid crystal compounds, two or more discotic liquid crystal compounds, or a mixture of a rod-shaped liquid crystal compound and a discotic liquid crystal compound may be used.

As the rod-shaped liquid crystal compound, for example, the one described in claim 1 of JP-A-11-513019 or the paragraphs [0026] to [0098] of JP-A-2005-289980 is preferably used. You can As the discotic liquid crystal compound, for example, those described in paragraphs [0020] to [0067] of JP2007-108732A, or paragraphs [0013] to [0108] of JP2010-244038A are suitable. Can be used for.

The retardation layer is more preferably formed using a liquid crystal compound having a polymerizable group (rod-shaped liquid crystal compound or disc-shaped liquid crystal compound). This makes it possible to reduce temperature changes and humidity changes in optical characteristics.

The liquid crystal compound may be a mixture of two or more kinds. In that case, it is preferable that at least one has two or more polymerizable groups. That is, the retardation layer is preferably a layer formed by fixing a rod-shaped liquid crystal compound having a polymerizable group or a discotic liquid crystal compound having a polymerizable group by polymerization. In this case, it is no longer necessary to exhibit liquid crystallinity after forming a layer.

The type of the polymerizable group contained in the rod-shaped liquid crystal compound or the discotic liquid crystal compound is not particularly limited, and examples thereof include a functional group capable of addition polymerization reaction such as a polymerizable ethylenically unsaturated group or a ring-polymerizable group. Is preferred. More specifically, for example, (meth)acryloyl group, vinyl group, styryl group, allyl group and the like can be mentioned. Of these, a (meth)acryloyl group is preferable. The (meth)acryloyl group is a concept that includes both a methacryloyl group and an acryloyl group.

The method for forming the retardation layer is not particularly limited, and known methods can be used. For example, a predetermined substrate (including a temporary substrate) is coated with a composition for forming an optically anisotropic layer (hereinafter, simply referred to as “composition”) containing a liquid crystal compound having a polymerizable group to form a coating film. Then, the retardation layer can be produced by subjecting the obtained coating film to a curing treatment (ultraviolet irradiation (light irradiation treatment) or heat treatment). The produced retardation layer can be transferred onto, for example, a polarizer or a protective film.

The composition can be applied by a known method, for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, or a die coating method.

The composition may contain components other than the above-mentioned liquid crystal compound. For example, the composition may include a polymerization initiator. As the polymerization initiator to be used, for example, a thermal polymerization initiator or a photopolymerization initiator is selected according to the type of polymerization reaction. Examples of the photopolymerization initiator include an α-carbonyl compound, an acyloin ether, an α-hydrocarbon-substituted aromatic acyloin compound, a polynuclear quinone compound, and a combination of a triarylimidazole dimer and p-aminophenyl ketone. The amount of the polymerization initiator used is preferably 0.01 to 20% by mass, and more preferably 0.5 to 5% by mass, based on the total solid content of the composition.

Further, the composition may contain a polymerizable monomer from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Among them, polyfunctional radically polymerizable monomers are preferable.

The polymerizable monomer is preferably one that is copolymerizable with the above-mentioned polymerizable group-containing liquid crystal compound. Specific examples of the polymerizable monomer include those described in paragraphs [0018] to [0020] in JP-A-2002-296423. The amount of the polymerizable monomer used is preferably 1 to 50% by mass, and more preferably 2 to 30% by mass, based on the total mass of the liquid crystal compound.

Further, the composition may contain a surfactant from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the surfactant include conventionally known compounds. Of these, fluorine compounds are particularly preferable.

The composition may contain a solvent, and an organic solvent is preferably used. Examples of the organic solvent include amides (eg, N,N-dimethylformamide), sulfoxides (eg, dimethylsulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg. , Chloroform, dichloromethane), esters (eg, methyl acetate, ethyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane).
Of these, alkyl halides and ketones are preferable. Also, two or more kinds of organic solvents may be used in combination.

The composition also includes a vertical alignment promoter such as a polarizer interface side vertical alignment agent and an air interface side vertical alignment agent, and a horizontal alignment promoter such as a polarizer interface side horizontal alignment agent and an air interface side horizontal alignment agent. Such various aligning agents may be included. Furthermore, the composition may contain an adhesion improver, a plasticizer, a polymer and the like in addition to the above components.

The retardation layer may include an alignment film having a function of defining the alignment direction of the liquid crystal compound. The alignment film generally contains a polymer as a main component. The polymer material for the alignment film is described in many documents, and many commercially available products can be obtained. Among them, it is preferable to use polyvinyl alcohol, polyimide, or a derivative thereof as the polymer material, and it is particularly preferable to use modified or unmodified polyvinyl alcohol.

The alignment film is generally subjected to a known alignment treatment. For example, a rubbing treatment, a photo-alignment treatment of applying polarized light and the like can be mentioned, but the photo-alignment treatment is preferable from the viewpoint of the surface roughness of the alignment film.

The thickness of the layer in which the liquid crystal compound is cured is not particularly limited, but is preferably 0.5 to 10 μm, more preferably 1.0 to 5 μm. Although the thickness of the alignment film is not particularly limited, it is often 20 μm or less, of which 0.01 to 10 μm is preferable, 0.01 to 5 μm is more preferable, and 0.01 to 5 μm. More preferably, it is 1 μm.

(4) Adhesive Layer The polarizing plate 10 preferably has an adhesive layer 15 on the outermost surface thereof. This pressure-sensitive adhesive layer can be used to bond the polarizing plate 10 to a display element (for example, a liquid crystal cell, an organic EL element) or another optical member, and is a pressure-sensitive adhesive layer that is exposed by peeling the release film 20. is there. The pressure-sensitive adhesive layer can also be used for laminating a polarizer, a protective film, a brightness enhancement film, and a retardation layer. In FIG. 1, the pressure-sensitive adhesive layer 16 corresponds to this. The pressure-sensitive adhesive layer can be composed of a pressure-sensitive adhesive composition containing a resin such as a (meth)acrylic resin, a rubber resin, a urethane resin, an ester resin, a silicone resin, or a polyvinyl ether resin as a main component. Above all, a pressure-sensitive adhesive composition containing a (meth)acrylic resin as a base polymer, which is excellent in transparency, weather resistance, heat resistance, etc., is preferable. The pressure-sensitive adhesive composition may be an active energy ray curable type or a thermosetting type.

Examples of the (meth)acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and (meth)acrylic acid 2- A polymer or copolymer having one or more (meth)acrylic acid ester monomers such as ethylhexyl as a monomer is preferably used. It is preferable to copolymerize a polar monomer with the base polymer. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, glycidyl ( Examples thereof include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like such as (meth)acrylate.

The pressure-sensitive adhesive composition may contain only the above base polymer, but usually further contains a crosslinking agent. As the cross-linking agent, a metal ion having a valence of 2 or more and forming a carboxylic acid metal salt with a carboxyl group; a polyamine compound forming an amide bond with a carboxyl group; Examples thereof include epoxy compounds and polyols that form an ester bond with a carboxyl group; and polyisocyanate compounds that form an amide bond with a carboxyl group. Of these, polyisocyanate compounds are preferable.

The active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by being irradiated with an active energy ray such as an ultraviolet ray or an electron beam, and has adhesiveness even before irradiation with the active energy ray. It is a pressure-sensitive adhesive composition having a property that it can be brought into close contact with an adherend such as the above, and can be cured by irradiation with an active energy ray to adjust the adhesion. The active energy ray-curable pressure-sensitive adhesive composition is preferably UV-curable. The active energy ray-curable pressure-sensitive adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the crosslinking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer or the like may be contained.

The pressure-sensitive adhesive composition includes fine particles for imparting light-scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than base polymers, antistatic agents, tackifiers, fillers (metal powders and Other inorganic powders), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, defoamers, corrosion inhibitors, photopolymerization initiators, and other additives.

The pressure-sensitive adhesive layer can be formed by applying a diluting solution of the pressure-sensitive adhesive composition in an organic solvent onto a substrate and drying. The substrate can be a polarizer, a protective film, another optical film such as a brightness enhancement film, a release film (eg, release film 20), and the like. When the active energy ray-curable pressure-sensitive adhesive composition is used, the formed pressure-sensitive adhesive layer can be irradiated with an active energy ray to obtain a cured product having a desired degree of curing.

The thickness of the pressure-sensitive adhesive layer 15 is usually 1 to 40 μm, but it is 3 to 25 μm (for example, 3 to 25 μm from the viewpoint of thinning the laminate and suppressing the dimensional change of the polarizing plate 10 while maintaining good workability. ˜20 μm, more preferably 3 to 15 μm). The pressure-sensitive adhesive layer 16 usually has a thickness of 1 to 20 μm, but preferably 3 to 10 μm.

The adhesive layer 15 on which the release film 20 is laminated can have an adhesion force to the release film of 0.20 N/25 mm or less, preferably 0.10 N/25 mm or less, and more preferably 0.05 N/25 mm. It is below, and may be below 0.04. With such adhesion, the polarizing plate does not float when the release film is peeled off, and the releasability is further improved. Further, the adhesion is 0.02 N/25 mm or more. With such an adhesive force, it is easy to prevent a gap from being formed between the release film and the pressure-sensitive adhesive layer even when an impact is applied to the laminate by transportation or the like. In the present specification, the adhesive force of the pressure-sensitive adhesive layer to the release film is a value measured by the method described in Examples below.

<Surface protection film>
The surface protection film 30 can include a base film 31 and a pressure-sensitive adhesive layer 32 laminated thereon. The surface protective film 30 is a film for protecting the surface of the polarizing plate 10, and is usually peeled and removed together with the pressure-sensitive adhesive layer of the laminated body after it is attached to a display element or another optical member. ..

The surface protection film has a product (K3) of the maximum force F3 (N) and the strain S3 (mm) in the bent state when the piercing jig is vertically lowered with respect to the surface protection film alone. , 0.15 N·mm or more, preferably 0.25 N·mm or more, and more preferably 0.40 N·mm or more. The product (K3) of the maximum force F3 (N) and the strain S3 (mm) is 1.00 N·mm or less, and may be 0.90 N·mm or less, or 0.80 N·mm. It may be the following, 0.70 N·mm or less, or 0.60 N·mm or less. The product (K3) of the maximum force F3(N) and the strain S3(mm) can be obtained by the same method as the method of obtaining the product of the maximum force F1(N) and the strain S1(mm) described above. ..

F3(N) can be 0.20N or more and 1.0N or less, and may be 0.3N or more and 0.6N or less. S3 (mm) can be 0.3 mm or more and 3.0 mm or less, and may be 0.5 mm or more and 2.0 mm or less.

The surface protection film generally has elasticity as compared with the brightness enhancement film, and is important for improving the releasability of the release film. In the present specification, the thickness of the surface protective film is a total value of the thickness of the substrate film and the thickness of the pressure-sensitive adhesive layer laminated thereon, preferably 30 μm or more, more preferably 50 μm or more. is there. On the other hand, when the thickness of the surface protective film is too large, when the peeling film is peeled off, peeling easily occurs between the surface protective film and the polarizing plate. Therefore, the thickness of the surface protective film is preferably 100 μm or less. , And more preferably 70 μm or less. However, even if the thickness is the same, the product of the maximum force F3(N) and the strain S3(mm) may differ depending on the material, the manufacturing method, and the like.

The base film is preferably a thermoplastic resin film. The thermoplastic resin that constitutes the thermoplastic resin film is, for example, a polyolefin resin such as a polyethylene resin or a polypropylene resin; a cyclic polyolefin resin; a polyester resin such as polyethylene terephthalate or polyethylene naphthalate; a polycarbonate resin; (Meth)acrylic resin etc. can be mentioned. The base film may have a single-layer structure or a multi-layer structure.

The thickness of the substrate film can be 20 to 150 μm (for example, 30 to 80 μm, preferably 30 to 60 μm). Regarding the constitution of the pressure-sensitive adhesive layer, the description about the pressure-sensitive adhesive layer included in the polarizing plate described above is basically cited.

In particular, the pressure-sensitive adhesive layer has a storage elastic modulus at 80° C. of preferably 0.15 MPa or less, more preferably 0.14 MPa or less, and further preferably 0.10 MPa or less. Usually, the storage elastic modulus of the adhesive layer at 80° C. is 0.01 MPa or more. In the present specification, the storage elastic modulus of the pressure-sensitive adhesive layer can be measured using a commercially available viscoelasticity measuring device, for example, a viscoelasticity measuring device “DYNAMIC ANALYZER RDA II” manufactured by REOMETRIC.

The surface protection film 30 may include an antistatic agent. The antistatic agent can be contained in the pressure-sensitive adhesive layer, for example. Instead of or in addition to containing the antistatic agent in the pressure-sensitive adhesive layer, an antistatic layer containing an antistatic agent may be provided on the surface of the base film opposite to the surface on which the pressure-sensitive adhesive layer is laminated. Good.

An ionic compound can be mentioned as an antistatic agent. The ionic compound is a compound having an inorganic cation or an organic cation and an inorganic anion or an organic anion.
Two or more ionic compounds may be used.

<Release film>
The release film 20 is a film that is temporarily attached to protect the surface of the adhesive layer until it is attached to a display element (for example, a liquid crystal cell or an organic EL element) or another optical member. The release film 20 can be adjusted in adhesion to the pressure-sensitive adhesive layer 15 by subjecting one surface of the release film 20 to a release treatment using a release agent such as a silicone-based or fluorine-based release agent. The release film 20 is composed of a release-treated thermoplastic resin film, and an adhesive layer can be attached to the release-treated surface.

The thermoplastic resin forming the release film 20 can be, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, or the like. The thickness of the release film 20 is, for example, 10 to 50 μm.

The laminates 100 to 103 can be attached to a display element (for example, a liquid crystal cell or an organic EL element) by removing the release film 20. Furthermore, the surface protection film 30 can be peeled off and incorporated into a display device (for example, a liquid crystal display device or an organic EL display device). In constructing a display device, the laminated body 10 according to the present invention may be used for a polarizing plate arranged on the viewing side, or may be used for a polarizing plate arranged on the backlight side, or on the viewing side. Also, it may be used for both polarizing plates on the backlight side.

For example, the release film can be released from the laminate as follows. The surface of the laminate on the surface protective film side is fixed to a holding table, and a release tape is attached to the release film. The method for fixing the laminate is not particularly limited, and may be fixed by a force of suction from the surface protective film side or may be fixed by an adhesive force. The adhesive force between the surface protection film to be fixed and the holding base is preferably 0.1 to 0.3 N/60 mm, and 0.15 to 0, from the viewpoint of leaving no mark on the polarizing plate. More preferably, it is 0.2 N/60 mm. According to the layered product of the present invention, even if the layered product is fixed with such a small pressure, good peelability is exhibited.
The position at which the release tape is attached is not particularly limited, and when the laminate has a rectangular shape, it can be attached at any of the four corners (diagonal portions) or at the center of any of the four sides. The release tape may be attached to one place of the release film or may be attached to a plurality of places. Then, the release tape is raised to release the release film. The peeling angle can be 90 to 180°, and the peeling speed is 0.1 to 10 m/min. Can be

Hereinafter, the present invention will be described more specifically by showing Examples and Comparative Examples, but the present invention is not limited to these Examples.

(1) Method of measuring rigidity (F×S) Using KES-G5, which is a compression tester manufactured by Kato Tech Co., Ltd., the maximum force F(N) and strain S(mm) in a state where each film is bent ) And were measured, and the product of both was calculated. This will be specifically described with reference to FIGS. 3 and 4. The size of the measuring film 3 was a rectangle having a short side of 25 mm (double-headed arrow 43)×long side of 43 mm (double-headed arrow 42). As the piercing jig 1, a needle having a spherical tip, a tip diameter of 1 mmφ, and a curvature of 0.5 R was used. As shown in FIG. 3, the film 3 to be measured was placed on the table 2, and the piercing jig 1 was dropped vertically to the film 3. The table 2 on which the film 3 is placed has a circular hole from the upper surface to the lower surface, and the hole diameter (double arrow 44) at the upper portion is 30 mm and the hole diameter on the lower surface (double arrow 41) is 10 mm. Is. The load on the piercing jig 1 was 1 kg, and the descending speed of the piercing jig was 1.0 cm/sec. After the piercing jig 1 comes into contact with the film 3 to be measured, the maximum load (N) and strain (in FIG. 4(a)) in a state where the film is warped (immediately before wrinkling or folding occurs) The length of the double-headed arrow 40) (mm) was measured.

(2) Method of measuring film thickness It was measured using MH-15M, a digital micrometer manufactured by Nikon Corporation.

(3) Adhesive force measurement method Adhesive force between the release film and the pressure-sensitive adhesive layer provided on the polarizing plate using Autograph (registered trademark) AGS-X, which is a tabletop precision universal testing machine manufactured by Shimadzu Corporation. Was measured.

(4) Method for evaluating peelability of release film The laminate produced in each example was fixed to a glass plate (holding table) so that the surface protection film was on the lower side. An adhesive sheet was used for fixing, and the fixing force (adhesion) was 0.1 to 0.3 N/60 mm. The release tape was attached to one of the four corners of the release film such that the long side direction of the release tape was parallel to the long side direction of the laminate. The peeling tape is a polyester adhesive tape manufactured by Nitto Denko Corporation No. 315 was used, the width was 12 mm, and the length of the bonded portion was 10 mm. One end of the release tape was gripped with a chuck, and the release film was released. The peeling speed was 3 m/min, and the peeling angle was 180°. At this time, when the layer composed of the polarizing plate and the surface protective film floated up from the glass on which the laminate was fixed, it was judged as peeling failure (NG), and when the peeling film could be peeled without rising, the peeling was good (OK). It was judged.

[Example 1]
A laminate was prepared as follows.
A polarizer (thickness 5 μm) in which iodine was adsorbed and oriented on a polyvinyl alcohol resin was produced. A cyclic olefin resin (COP) film (manufactured by Nippon Zeon Co., Ltd., thickness 30 μm) having a hard coat layer formed thereon is bonded to one surface of this polarizer through a UV-curable adhesive to form a polarizer. A retardation layer (thickness: 20 μm) made of a cyclic olefin resin was attached to the other surface of the above through the same adhesive.
Then, a retardation layer (thickness 5 μm) including a layer in which the polymerizable liquid crystal compound was cured was formed on the cyclic olefin resin film. An acrylic pressure-sensitive adhesive layer (thickness 20 μm) was formed on a release film (thickness 38 μm) made of a polyester resin film, and this acrylic pressure-sensitive adhesive layer was laminated on the retardation layer. A surface protective film (thickness is 65 μm in total of the base film and the acrylic pressure-sensitive adhesive layer) including a base film (thickness 50 μm) made of a polyester resin and an acrylic pressure-sensitive adhesive layer (thickness 15 μm) is prepared. This acrylic pressure-sensitive adhesive layer was laminated on the cyclic olefin resin film on which the hard coat layer was formed to obtain a film.

The obtained film was cut into a rectangle having a long side of 26.6 cm and a short side of 20.0 cm to obtain a laminate. The laminate has a layer structure of a peeling film/adhesive layer/retardation layer (a layer in which a liquid crystal compound is cured)/retardation layer (COP film)/polarizer/COP film having a hard coat layer formed thereon/surface protection film. Had. The thickness of the polarizing plate [pressure-sensitive adhesive layer/retardation layer (cured layer of liquid crystal compound)/retardation layer (COP film)/polarizer/COP film having hard coat layer] in this laminate was 80 μm. The thickness of the release film was 38 μm, and the thickness of the surface protection film was 65 μm.

Further, the release film (38 μm) was peeled off from the film obtained above leaving the pressure-sensitive adhesive layer to obtain a layer consisting of a polarizing plate and a surface protective film, and this layer was cut into a rectangle of 25 mm×43 mm for measurement. Film 3 was used, and the maximum force (F) in the flexed state was measured as F1 and the strain (S) was measured as S1 by the above measuring method.
From the film obtained above, the release film (thickness 38 μm) was peeled off leaving the pressure-sensitive adhesive layer, and the surface protective film (thickness 65 μm) was further peeled off to obtain a polarizing plate (thickness 80 μm). The measurement film 3 is cut out into a 43 mm rectangle, and the maximum force (F) in the flexed state is measured as F2 and the maximum strain (S) in the flexed state is measured as S2 by the above measuring method. And The surface protection film used above was cut into a rectangle of 25 mm×43 mm to be used as a measuring film, and the maximum force (F) in the flexed state was measured by the above measuring method to be F3, and the strain (S) in the flexed state Was measured to be S3. As a result, F1=2.69 N, S1=3.4 mm, F2=0.52 N, S2=1.1 mm, F3=0.46 N, and S3=1.6 mm.

The adhesive force between the pressure-sensitive adhesive layer and the release film was 0.04 N/25 mm, and no peeling was observed between the pressure-sensitive adhesive layer and the release film due to transportation or the like.

[Example 2]
A laminate was prepared as follows.
A polarizer (thickness 8 μm) in which iodine was adsorbed and oriented on a polyvinyl alcohol-based resin was produced. A cyclic olefin resin film (manufactured by Nippon Zeon Co., Ltd., thickness 30 μm) having a hard coat layer formed thereon was attached to one surface of this polarizer via an aqueous adhesive. A surface protective film (Fujimori Industry Co., Ltd., trade name FS-PF) comprising a base film (thickness 38 μm) made of polyester resin and an acrylic pressure-sensitive adhesive layer (thickness 17 μm) was prepared. The layer was laminated on the cycloolefin resin film having the hard coat layer formed thereon.

The following laminated film was laminated on the other surface of the polarizer via an ultraviolet curable adhesive. This laminated film was prepared by curing a polymerizable liquid crystal compound on a retardation layer (manufactured by Nippon Zeon Co., Ltd., thickness 20 μm, in-plane retardation value Re(590)=120 to 150 nm) made of a cyclic olefin resin film. The phase difference layer (thickness 1 μm, retardation value Rth(590)=−110 to −150 nm in the thickness direction) is laminated. The laminated surface was laminated so that the laminated surface with the polarizer would be the COP film surface of the laminated film.

An acrylic pressure-sensitive adhesive layer (Lintec Co., Ltd., thickness 13 μm, #KC1) was formed on a release film (thickness 38 μm) made of a polyester resin film, and this acrylic pressure-sensitive adhesive layer was laminated on the retardation layer. ..

The obtained film was cut into a rectangle having a long side of 26.6 cm and a short side of 20.0 cm to obtain a laminate. The laminate has a layer structure of a peeling film/adhesive layer/retardation layer (a layer in which a liquid crystal compound is cured)/retardation layer (COP film)/polarizer/COP film having a hard coat layer formed thereon/surface protection film. Had. The polarizing plate had a thickness of 72 μm, the release film had a thickness of 38 μm, and the surface protective film had a thickness of 55 μm.

Further, F1=2.23 N, S1=2.6 mm, F2=0.56 N, S2=1.5 mm, F3=0.30 N, and S3=0.7 mm.

The adhesive force between the pressure-sensitive adhesive layer and the release film was 0.02 N/25 mm, and no peeling was observed between the pressure-sensitive adhesive layer and the release film due to transportation or the like.

[Example 3]
A laminate was prepared as follows.
A polarizer (thickness 8 μm) in which iodine was adsorbed and oriented on a polyvinyl alcohol-based resin was produced. A cyclic olefin resin film (manufactured by Nippon Zeon Co., Ltd., thickness 30 μm) having a hard coat layer formed thereon was attached to one surface of this polarizer via an aqueous adhesive. A surface protective film (Fujimori Industry Co., Ltd., trade name FS-PF) comprising a base film (thickness 38 μm) made of polyester resin and an acrylic pressure-sensitive adhesive layer (thickness 17 μm) was prepared. The layer was laminated on the cycloolefin resin film having the hard coat layer formed thereon.

The following laminated film was laminated on the other surface of the polarizer via an ultraviolet curable adhesive.
This laminated film had a position where a polymerizable liquid crystal compound was cured on a retardation layer (manufactured by Nippon Zeon Co., Ltd., thickness 22 μm, in-plane retardation value Re(590)=120 to 150 nm) made of a cyclic olefin resin film. The phase difference layer (thickness 1 μm, thickness direction retardation value Rth(590)=−110 to −150 nm) is laminated. The laminated surface was laminated so that the laminated surface with the polarizer would be the COP film surface of the laminated film. An acrylic pressure-sensitive adhesive layer (manufactured by Lintec Corporation, thickness 13 μm, #KC1) was formed on a release film (thickness 38 μm) made of a polyester-based resin film having a smaller amount of silicone than that of Example 2. The agent layer was laminated on the retardation layer.

The obtained film was cut into a rectangle having a long side of 26.6 cm and a short side of 20.0 cm to obtain a laminate. The laminate has a layer structure of a peeling film/adhesive layer/retardation layer (a layer in which a liquid crystal compound is cured)/retardation layer (COP film)/polarizer/COP film having a hard coat layer formed thereon/surface protection film. Had. The polarizing plate had a thickness of 74 μm, the release film had a thickness of 38 μm, and the surface protective film had a thickness of 55 μm.

Further, F1=2.15N, S1=3.4 mm, F2=0.61N, S2=1.6 mm, F3=0.30N, and S3=0.7 mm.

The adhesive force between the pressure-sensitive adhesive layer and the release film was 0.04 N/25 mm, and no peeling was observed between the pressure-sensitive adhesive layer and the release film due to transportation or the like.

[Example 4]
A laminate was prepared as follows.
A polarizer (thickness 8 μm) in which iodine was adsorbed and oriented on a polyvinyl alcohol-based resin was produced. A brightness enhancement film (3M, APF-V3, thickness 30 μm) was attached to one surface of this polarizer via an adhesive layer (thickness 5 μm), and ultraviolet light was applied to the other surface of the polarizer. A cycloolefin resin film (manufactured by Nippon Zeon Co., Ltd., thickness: 13 μm) was attached via a curable adhesive. An acrylic pressure-sensitive adhesive layer (Lintec Co., Ltd., thickness 13 μm, #KC1) was formed on a release film (thickness 38 μm) made of a polyester resin film, and this acrylic pressure-sensitive adhesive layer was laminated on the cyclic olefin resin film. Let A surface protection film (manufactured by San-A Kaken Co., Ltd., trade name OF-PF) consisting of a base film (thickness 38 μm) made of polyester resin and an acrylic pressure-sensitive adhesive layer (thickness 15 μm) was prepared. Layers were laminated onto the brightness enhancement film.

The obtained film was cut into a rectangle having a long side of 26.6 cm and a short side of 20.0 cm to obtain a laminate. The laminate had a layer structure of release film/adhesive layer/COP film/polarizer/adhesive layer/brightness enhancement film/surface protection film. The polarizing plate had a thickness of 69 μm, the release film had a thickness of 38 μm, and the surface protective film had a thickness of 53 μm.

Also, F1=1.62N, S1=3.5 mm, F2=0.61N, S2=1.6 mm, F3=0.21N, and S3=0.7 mm.

The adhesive force between the pressure-sensitive adhesive layer and the release film was 0.02 N/25 mm, and no peeling was observed between the pressure-sensitive adhesive layer and the release film due to transportation or the like.

[Example 5]
The laminated body was produced as follows.
A polarizer (thickness 8 μm) in which iodine was adsorbed and oriented on a polyvinyl alcohol-based resin was produced. A brightness enhancement film (3M, APF-V4, thickness 20 μm) was attached to one surface of the polarizer via an adhesive layer (thickness 15 μm), and ultraviolet light was applied to the other surface of the polarizer. A cycloolefin resin film (manufactured by Nippon Zeon Co., Ltd., thickness: 13 μm) was attached via a curable adhesive. An acrylic pressure-sensitive adhesive layer (Lintec Co., Ltd., thickness 13 μm, #KC1) was formed on a release film (thickness 38 μm) made of a polyester resin film, and this acrylic pressure-sensitive adhesive layer was laminated on the cyclic olefin resin film. Let A surface protection film (Fujimori Industry Co., Ltd., trade name FY-PF) consisting of a base film (thickness 50 μm) made of polyester resin and an acrylic pressure-sensitive adhesive layer (thickness 15 μm) was prepared, and this acrylic pressure-sensitive adhesive was used. Layers were laminated onto the brightness enhancement film.

The obtained film was cut into a rectangle having a long side of 26.6 cm and a short side of 20.0 cm to obtain a laminate. The laminate had a layer structure of release film/adhesive layer/COP film/polarizer/adhesive layer/brightness enhancement film/surface protection film. The polarizing plate had a thickness of 69 μm, the release film had a thickness of 38 μm, and the surface protective film had a thickness of 65 μm.

Further, F1=1.62N, S1=2.4 mm, F2=0.25N, S2=0.7 mm, F3=0.42N, and S3=1.3 mm.

The adhesive force between the pressure-sensitive adhesive layer and the release film was 0.02 N/25 mm, and no peeling was observed between the pressure-sensitive adhesive layer and the release film due to transportation or the like.

[Comparative Example 1]
A laminate was prepared as follows.
A polarizer (thickness 8 μm) in which iodine was adsorbed and oriented on a polyvinyl alcohol-based resin was produced. At the time of producing the polarizer, the stretching ratio was higher than that of the polarizer of Example 5. A brightness enhancement film (3M, APF-V4, thickness 20 μm) was attached to one surface of this polarizer via an adhesive layer (thickness 15 μm), and ultraviolet light was applied to the other surface of the polarizer. A cycloolefin resin film (manufactured by Nippon Zeon Co., Ltd., thickness: 13 μm) was attached via a curable adhesive. An acrylic pressure-sensitive adhesive layer (Lintec Co., Ltd., thickness 13 μm, #KC1) was formed on a release film (thickness 38 μm) made of a polyester resin film, and this acrylic pressure-sensitive adhesive layer was laminated on the cyclic olefin resin film. Let A surface protective film (manufactured by Fujimori Industry Co., Ltd., trade name AY-XA35) consisting of a base film (thickness 38 μm) made of polyester resin and an acrylic pressure-sensitive adhesive layer (thickness 15 μm) was prepared, and this acrylic pressure-sensitive adhesive was used. Layers were laminated onto the brightness enhancement film.

The obtained film was cut into a rectangle having a long side of 26.6 cm and a short side of 20.0 cm to obtain a laminate. The laminate had a layer structure of release film/adhesive layer/cycloolefin resin film/polarizer/adhesive layer/brightness enhancement film/surface protection film. The polarizing plate had a thickness of 69 μm, the release film had a thickness of 38 μm, and the surface protective film had a thickness of 53 μm.

Further, F1=1.09N, S1=2.1 mm, F2=0.24N, S2=0.6 mm, F3=0.22N, and S3=0.5 mm.

The adhesive force between the pressure-sensitive adhesive layer and the release film was 0.02 N/25 mm, and no peeling was observed between the pressure-sensitive adhesive layer and the release film due to transportation or the like.

[Comparative example 2]
A laminate was prepared as follows.
A polarizer (thickness 8 μm) in which iodine was adsorbed and oriented on a polyvinyl alcohol-based resin was produced. A brightness enhancement film (3M, APF-V4, thickness 20 μm) was attached to one surface of this polarizer via an adhesive layer (thickness 15 μm), and the other surface of the polarizer was bonded. A cyclic olefin-based resin film (manufactured by Nippon Zeon Co., Ltd., thickness 13 μm) was attached via the agent. An acrylic pressure-sensitive adhesive layer (Lintec Co., Ltd., thickness 13 μm, #KC1) was formed on a release film (thickness 38 μm) made of a polyester resin film, and this acrylic pressure-sensitive adhesive layer was laminated on the cyclic olefin resin film. Let A surface protective film (manufactured by Fujimori Industry Co., Ltd., trade name AY-XA35) consisting of a base film (thickness 38 μm) made of polyester resin and an acrylic pressure-sensitive adhesive layer (thickness 15 μm) was prepared, and this acrylic pressure-sensitive adhesive was used. Layers were laminated onto the brightness enhancement film.

The obtained film was cut into a rectangle having a long side of 26.6 cm and a short side of 20.0 cm to obtain a laminate. The laminate had a layer structure of release film/adhesive layer/cycloolefin resin film/polarizer/adhesive layer/brightness enhancement film/surface protection film. The polarizing plate had a thickness of 69 μm, the release film had a thickness of 38 μm, and the surface protective film had a thickness of 53 μm.

Also, F1=1.21N, S1=1.8 mm, F2=0.25N, S2=0.7 mm, F3=0.25N, and S3=0.5 mm.

The adhesive force between the pressure-sensitive adhesive layer and the release film was 0.02 N/25 mm, and no peeling was observed between the pressure-sensitive adhesive layer and the release film due to transportation or the like.

[Comparative Example 3]
A laminate was prepared as follows.
A polarizer (thickness 5 μm) in which iodine was adsorbed and oriented on a polyvinyl alcohol resin was produced. A brightness enhancement film (3M, APF-V4, thickness 20 μm) was attached to one surface of the polarizer via an adhesive layer (thickness 5 μm), and the other surface of the polarizer was bonded. A protective film (thickness: 20 μm) made of an acrylic resin was attached via the agent. An acrylic pressure-sensitive adhesive layer (thickness 21 μm) was formed on a release film (thickness 38 μm) made of a polyester resin film, and this acrylic pressure-sensitive adhesive layer was laminated on the protective film made of the acrylic resin. A surface protective film composed of a base film (thickness 40 μm) made of polyester resin and an acrylic pressure-sensitive adhesive layer (thickness 16 μm) was prepared, and this acrylic pressure-sensitive adhesive layer was laminated on the brightness enhancement film.

The obtained film was cut into a rectangle having a long side of 26.6 cm and a short side of 20.0 cm to obtain a laminate. The laminate had a layer structure of release film/adhesive layer/optical protective film/polarizer/adhesive layer/brightness improving film/surface protective film. The polarizing plate had a thickness of 71 μm, the release film had a thickness of 38 μm, and the surface protective film had a thickness of 56 μm.

Further, F1=1.55N, S1=2.3 mm, F2=0.24N, S2=1.3 mm, F3=0.21N, and S3=1.1 mm.

The adhesive force between the pressure-sensitive adhesive layer and the release film was 0.04 N/25 mm, and no peeling was observed between the pressure-sensitive adhesive layer and the release film due to transportation or the like.

The peelability of the laminates produced in Examples 1 to 5 and Comparative Examples 1 to 3 was evaluated.
The results are shown in Table 1. As shown in Table 1, in the laminates of Examples 1 to 5, the release film could be favorably peeled off. Further, in any of the examples, no defect of peeling between the polarizing plate and the surface protective film occurred.

[Table 1]
─────────────────────────────
Experimental example Adhesion K1 K2 K3 Peelability
[N/25mm] [N・mm] [N・mm] [N・mm] Evaluation
─────────────────────────────
Example 1 0.04 9.1 0.56 0.75 OK
Example 2 0.02 5.7 0.83 0.20 OK
Example 3 0.04 7.3 0.99 0.20 OK
Example 4 0.02 5.6 0.77 0.14 OK
Example 5 0.02 3.8 0.18 0.53 OK
─────────────────────────────
Comparative Example 1 0.02 2.3 0.14 0.10 NG
Comparative Example 2 0.02 2.2 0.18 0.11 NG
Comparative Example 3 0.04 3.6 0.31 0.23 NG
─────────────────────────────

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a laminate that does not cause peeling defects of the release film even if the polarizing plate has low rigidity, which is useful.

1 Puncture jig 2 Units 3 Film to be measured 10 Polarizing plate 11 Polarizer 12, 13 Protective film 14 Brightness improving film 15 Adhesive layer 16 Adhesive layer 17 Phase difference layer 20 Release film 30 Surface protective film 31 Base film 32 adhesive layer 40, 41, 42, 43, 44 double-headed arrow 100, 101, 102, 103 laminate

Claims (4)

A surface protective film is peelably laminated on one side of the polarizing plate,
A release film is releasably laminated on the other surface of the polarizing plate via an adhesive layer,
The polarizing plate includes a polarizer,
When the surface protection film is used as a measurement film and the maximum force (F(N)) measured by the following measurement method is F3 and the strain (S(mm)) is S3, the maximum force F3(N) And a strain S3 (mm) (F3 (N) x S3 (mm)) has a rigidity K3 of 1.00 N·mm or less,
The maximum force (F(N)) measured by the following measuring method was F1 and the strain (S(mm)) was S1 with the layer comprising the polarizing plate and the surface protective film as a measuring film. At times, the rigidity K1 expressed as the product of the maximum force F1(N) and the strain S1(mm) (F1(N)×S1(mm)) is 3.70 N·mm or more and 10.0 N·mm or less. A stack.
Measuring method:
It has a circular through hole in the center when viewed from the top surface, the diameter of the through hole on the top surface is 30 mm, and the shape of the through hole viewed from the side surface is a shape composed of a columnar lower part and a hemispherical upper part. On the measuring table,
Place a rectangular measuring film of 25 mm x 43 mm,
From above the measuring film, a needle having a spherical tip, a tip diameter of 1 mmφ and a radius of curvature of 0.5 mm was placed at 1.0 cm/sec so that the needle would pass through the center of the through hole of the measuring table. Vertically at the speed of
After the tip of the needle comes into contact with the film for measurement, the maximum load for maintaining the bent state of the film is measured as the maximum force F(N), and the strain S (mm) of the film at that time is measured. The maximum force F2(N) is F2(N) and the strain (S(mm)) is S2. The laminate K according to claim 1, wherein a rigidity K2 represented as a product of the strain and a strain S2 (mm) is 1.00 N·mm or less. The laminate according to claim 1 or 2, wherein the adhesive force between the polarizing plate and the release film is 0.02 to 0.05 N/25 mm. Fixing the surface protection film in the laminate according to any one of claims 1 to 3 on a holding table with an adhesive force of 0.1 to 0.3 N/60 mm;
A method for producing a polarizing plate with a surface protective film, which comprises a step of peeling a release film from the laminate.