WO2018221232A1

WO2018221232A1 - Optical film, release method, and method for manufacturing optical display panel

Info

Publication number: WO2018221232A1
Application number: PCT/JP2018/019026
Authority: WO
Inventors: 慎哉平岡; 岸　敦史; 裕美池嶋
Original assignee: 日東電工株式会社
Priority date: 2017-05-31
Filing date: 2018-05-17
Publication date: 2018-12-06
Also published as: TWI681205B; KR20190133203A; TW201903437A; JP6920108B2; JP2018202656A; CN110730717B; CN110730717A; KR102338615B1

Abstract

The present invention is a sheet-form film laminate in which a first release film having a first base-material film and a second release film having a functional film and a second base-material film are laminated, wherein the first release film is detached prior to the second release film, the functional film has a thickness of 110 μm or less, and a first bending resistance (mm) in a bending test of the first release film is greater than a second bending resistance (mm) in a bending test of the second release film. In this laminate, the first release film (the release film on the side that is released first) can be easily released even when a thin functional film is used.

Description

Optical film, peeling method, and manufacturing method of optical display panel

The present invention relates to a sheet-like film laminate in which a first release film, a functional film, and a second release film are laminated in this order.

Moreover, this invention relates to the peeling method of the 1st peeling film which concerns on the said film laminated body. Furthermore, this invention relates to the manufacturing method of the optical display panel using the said film laminated body.

The functional film may be protected with a release film on both sides until it is used for various purposes. For example, when an optical film such as a polarizing film is used as an optical film with an adhesive layer provided with an adhesive layer for adhering to an optical cell such as a liquid crystal cell on one side, generally, A release film (release film) is temporarily attached to the adhesive layer until it is applied for bonding. On the other hand, another release film (surface protective film) is temporarily attached to the other surface of the optical film. Such an optical film with an adhesive layer having a release film and a surface protective film is applied to an optical display panel. In this case, first, the release film is peeled from the optical film with an adhesive layer. The pressure-sensitive adhesive layer exposed is bonded to the optical cell. The surface protective film is directly bonded to the bonded optical film with the pressure-sensitive adhesive layer.

The bonding is, for example, a method in which the optical film with the pressure-sensitive adhesive layer fed out from the wound body is bonded to the surface of the optical cell via the pressure-sensitive adhesive layer exposed by peeling off the release film (hereinafter referred to as the adhesive layer). Also referred to as “roll-to-panel method.” Patent Document 1). In addition, a method of attaching the optical film with the pressure-sensitive adhesive layer in a single wafer state to the optical cell through the pressure-sensitive adhesive layer exposed by peeling off the release film (hereinafter also referred to as “sheet-to-panel method”). )

On the other hand, image display devices such as liquid crystal display devices are becoming thinner, and the polarizing film is also required to be thinner. Therefore, thinning is also performed for the polarizer (Patent Document 2). Further, the polarizing film can be thinned by using a single protective polarizing film in which a protective film is provided only on one side of the polarizer and no protective film is provided on the other side. The single-protective polarizing film can be a thin type because the protective film is less than one protective polarizing film provided with protective films on both sides of the polarizer.

Japanese Patent No. 4406043 Japanese Patent No. 4751481

When peeling a release film from an optical film with an adhesive layer having a release film and a surface protective film (for example, a polarizing film with an adhesive layer), the surface protective film of the optical film with an adhesive layer is usually used. With the side fixed, the release film is peeled off. However, in recent years, there has been an increasing demand for a mode in which the surface protective film can be easily peeled without any adhesive residue, and the peel strength of the surface protective film has been further reduced. Originally, from the viewpoint of the peeling order, the release film that is peeled first is designed so that the peeling force is sufficiently small (easy to peel) compared to the surface protective film that is peeled later. It is desirable. However, in recent years, the optical film with an adhesive layer designed so that the peel strength of the surface protective film is not sufficiently large or the peel strength of the surface protective film is smaller than the peel strength of the release film. It was newly discovered that it was proposed. Therefore, when the release film is peeled off, there is a problem that peeling occurs not at the interface between the release film and the pressure-sensitive adhesive layer but at the interface between the optical film (for example, a polarizing film) and the surface protective film. The problem can be solved, for example, by making the peeling force of the surface protective film and the peeling force of the release film substantially the same. However, the release film is required to have a peeling force that exceeds a predetermined level in order to ensure the adhesion between the optical film and the optical cell. Therefore, the release film is designed to have the same release force as that of the surface protective film. In this case, the adhesive force between the optical film and the optical cell is reduced, or the demand for reducing the peeling force of the surface protective film cannot be met. In particular, the above problem is apparent when a release film is peeled from a sheet-like polarizing film with a pressure-sensitive adhesive layer having a thin polarizing film of a predetermined thickness or less (for example, a thickness of 60 μm or less) in a sheet-to-panel system. I found out that

The present invention is a sheet-like film laminate having a first release film and a second release film on both sides of a functional film, and even when a thin functional film is used, It is an object of the present invention to provide a film laminate capable of easily peeling off a peeling film on the side to be peeled.

Moreover, this invention aims at providing the peeling method of the 1st peeling film which concerns on the said film laminated body, Furthermore, this invention aims at providing the manufacturing method of the optical display panel using the said film laminated body. .

As a result of intensive studies, the present inventors have found that the above problems can be solved by the following film laminate and the like, and have reached the present invention.

That is, the present invention is a sheet-like film laminate in which a first release film having a first base film, a functional film, and a second release film having a second base film are laminated in this order,
The functional film has a thickness of 110 μm or less, and
The present invention relates to a film laminate, wherein the first bending softness (mm) in the first peeling film bending test is larger than the second bending softness (mm) in the second peeling film bending test.

In the film laminate, the difference between the first bending resistance (mm) and the second bending resistance (mm) is preferably 10 mm or more.

In the film laminate, the present invention is suitable when the peel force (1) of the first peel film is equal to or greater than the peel force (2) of the second peel film.

In the film laminate, the thickness of the first base film is preferably larger than the thickness of the second base film.

In the film laminate, the thickness of the first base film is preferably 40 μm or more.

In the film laminate, the second base film preferably has a thickness of 35 μm or less.

In the film laminate, an optical film can be used as the functional film.

A polarizing film can be used as the optical film. The said polarizing film is applied suitably when it has a polarizer whose thickness is 10 micrometers or less. Moreover, it applies suitably, when the said polarizing film is a piece protection polarizing film which has a protection film only in the single side | surface of a polarizer.

Further, as the optical film, one having a surface treatment layer on one side or both sides can be used.

In the film laminate, a surface protective film can be used as the first release film and the second release film.

In the said film laminated body, when the said functional film has an adhesive layer for functional films in the side which provides a 1st peeling film, the aspect using a surface protection film is suitably applied as a said 2nd peeling film. .

In the film laminate, the surface protective film having a pressure-sensitive adhesive layer for the surface protective film can be used, and the surface protective film can be laminated on the functional film via the pressure-sensitive adhesive layer. Moreover, a self-adhesive film can be used as the surface protective film.

Also, the present invention relates to a first peeling film peeling method characterized by peeling the first peeling film from the film laminate.

Moreover, this invention is a process (1) which prepares the said film laminated body,
A step (2) of peeling the first release film from the film laminate, and
It is related with the manufacturing method of the optical display panel which has the process (3) which affixes the side of the adhesive layer for functional films of the said film laminated body from which the said 1st peeling film peeled to the one surface of an optical cell.

In the method for manufacturing an optical display panel, a liquid crystal cell or an organic EL cell can be used as the optical cell.

The film laminate of the present invention has a first release film (a release film that is peeled first in the film laminate) and a second release film (a peel that is peeled off after the first release film is peeled) on both sides of the functional film. The first release film has a higher bending resistance (mm) in the bending resistance test than the second release film. By peeling off the first release film by the design of the film laminate, the shear force in the cross-sectional direction of the functional film is larger at the interface of the first release film than at the interface of the functional film and the second release film. It is thought that it will come to join. As a result, even when the thickness of the functional film is 110 μm or less and the waist (elastic modulus) is weak (further, when the peeling force of the second peeling film is smaller than the peeling force of the first peeling film), In the sheet-to-panel system, the first release film can be easily peeled from the sheet-like film laminate without causing peeling at the interface between the functional film and the second release film.

It is a cross-sectional schematic diagram of the film laminated body of the single wafer state of this invention. It is a cross-sectional schematic diagram of the film laminated body of the sheet | seat state of another embodiment of this invention. It is a cross-sectional schematic diagram of the film laminated body of the sheet | seat state of another embodiment of this invention. It is a cross-sectional schematic diagram of the film laminated body of the sheet | seat state of another embodiment of this invention. It is a cross-sectional schematic diagram of the film laminated body of the sheet | seat state of another embodiment of this invention. It is the schematic which shows the bending resistance in a bending resistance test.

Hereinafter, the film laminate F of the present invention will be described with reference to the drawings. 1 to 5 are schematic cross-sectional views of the film laminate F. FIG. The film laminate F has a configuration in which the first release film 1, the functional film A, and the second release film 2 are laminated in this order.

In FIG. 2, FIG. 3, it has the adhesive layer B for functional films on the single side | surface of the functional film A, the 1st peeling film 1 is provided in the said adhesive layer B for functional films, and the other side of the functional film A Is a mode in which the second release film 2 is provided. The first release film 1 has a first base film, and the second release film 2 has a second base film.

2 and 3, the first release film 1 is used as a release film for protecting the functional film pressure-sensitive adhesive layer B until practical use. In addition to having the first base film, the first release film 1 includes, for example, the functional film pressure-sensitive adhesive layer B of the first base film in order to enhance the peelability from the functional film pressure-sensitive adhesive layer B. A peeling treatment layer or the like can be provided on the side to be bonded (not shown). In addition, when not providing a peeling process layer etc. in a 1st base film, the thickness of a 1st base film respond | corresponds to the thickness of the 1st release film 1. FIG.

On the other hand, in the embodiment of FIGS. 2 and 3, the second release film 2 is used as a surface protective film. The case where the 2nd peeling film 2 (surface protection film) of FIG. 2, FIG. 3 has the 2nd base film 21 and the adhesive layer 22 for surface protection films is illustrated. 2 and 3, the surface protective film pressure-sensitive adhesive layer 22 side of the second release film 2 is bonded to the functional film A. FIG. 1 conceptually shows the case where the second release film 2 is a self-adhesive film. When the second release film 2 is a self-adhesive film, the thickness of the self-adhesive film corresponds to the thickness of the second base film.

FIG. 3 shows a case where the functional film A is a piece protective polarizing film having the protective film a2 only on one side of the polarizer a1. In addition, in FIG. 3, although the case where it has the adhesive layer B for functional films in the polarizer a1 side in the piece protection polarizing film is illustrated, the piece protection polarizing film is the adhesive for functional films on the protection film a2 side. It can also be arranged to have layer B. In addition, as the functional film A of FIG. 2, various optical films can be used, for example, and both protective polarizing films which have the protective film a2 on both surfaces of the polarizer a1 can be used.

4 and 5 are embodiments in which the first release film 1 is provided as a surface protective film on one side of the functional film A, and the second release film 2 is provided as a surface protective film on the other side.

4 and FIG. 5, the case where the 1st peeling film 1 has the 1st base film 11 and the adhesive layer 12 for surface protection films is illustrated. 4 and 5, the surface protective film pressure-sensitive adhesive layer 12 side of the first release film 1 is bonded to the functional film A. On the other hand, in the embodiment of FIGS. 4 and 5, the second release film 2 is illustrated as having the second base film 21 and the surface protective film pressure-sensitive adhesive layer 22 as in FIGS. 2 and 3. .

FIG. 5 illustrates the case where the functional film A has the surface treatment layer a4 on both surfaces of the functional substrate film a3. In addition, as the functional film A of FIG. 5, various optical films can be used, for example, and what has the surface treatment layer a4 only on the single side | surface of the functional base film a3 can be used.

In the film laminate of the present invention, the first stiffness (mm) in the stiffness test of the first release film 1 is greater than the second stiffness (mm) in the stiffness test of the second release film 2. Thus, the first release film and the second release film are selected. The difference between the first bending resistance (mm) and the second bending resistance (mm) is preferably 10 mm or more from the viewpoint of the stability of the peeling accuracy (in the pickup test), and further 20 mm or more, Furthermore, it is preferable that it is 30 mm or more.

Both the first release film 1 and the second release film 2 are finally peeled off. The peel force (1) of the first peel film 1 and the peel force (2 of the second peel film 2) ) Is preferably designed to have a suitable peeling force. For example, in the embodiments of FIGS. 2 and 3, the peel force (1) is the peel force of the first release film 1 with respect to the functional film pressure-sensitive adhesive layer B. In the embodiments of FIGS. ) Is the peeling force of the first release film 1 with respect to the functional film A. The peeling force (2) is the peeling force of the second release film 2 with respect to the functional film A.

The peeling force (1) is preferably 0.03 N / 25 mm or more from the viewpoint of preventing end lifting during processing. Furthermore, it is preferably 0.05 to 0.5 N / 25 mm, more preferably 0.1 to 0.3 N / 25 mm. Further, the peeling force (2) is preferably 0.2 N / 25 mm or less, more preferably 0.01 to 0.1 N / 25 mm, and further preferably 0.01 from the viewpoint of simple peeling. It is preferable to be 0.05 N / 25 mm.

The film laminate F of the present invention is suitably applied when the peel force (1) of the first peel film 1 is greater than or equal to the peel force (2) of the second peel film 2. In particular, the present invention is suitably applied to the case where the peeling force (1) is designed to be larger than the peeling force (2). In the film laminate F of the present invention, the value {peeling force (1) / peeling force (2)} of the peel force (1) with respect to the peel force (2) is 1.1 times or more, and further 1 It is suitable when it is 5 times or more.

In the film laminate F of the present invention, the thickness of the first base film of the first release film 1 is preferably larger than the thickness of the second base film of the second release film 2. The bending resistance of the film substrate is affected by the film thickness, and the bending resistance tends to increase as the film thickness increases. Therefore, by designing the thickness of the first base film to be larger than the thickness of the second base film, the first bending degree of the first peeling film is changed to the second bending degree of the second peeling film. It can be adjusted to be larger. In particular, when the first base film and the second base film are the same forming material, the bending resistance can be easily adjusted by the thickness.

In addition, the various treatment layers such as the release treatment layers in the first and second release films and the pressure-sensitive adhesive layer for the surface protection film when used as the surface protection film have little influence on the bending resistance. Therefore, the first bending resistance of the first release film is determined by the material and thickness of the first base film, and the second bending resistance of the second release film is determined by the material and thickness of the second base film. .

The thickness of the first base film of the first release film is usually preferably 40 to 240 μm, more preferably 45 to 230 μm, and further preferably 50 to 220 μm. On the other hand, the thickness of the second base film of the second release film is usually preferably 5 to 150 μm, more preferably 10 to 100 μm.

<Functional film>
Functional films are various films used according to the field in various fields. For example, in the optical field, a polarizing film, a transparent protective film, a retardation film, an antireflection film, a brightness enhancement film, a diffusion film, etc. An optical film is used.

The functional film having a thickness (total thickness) of 110 μm or less is used. The thickness of the functional film is preferably 95 μm or less, and more preferably 80 μm or less. When the thickness of the functional film is 110 μm or less, in the sheet-to-panel method, when the first release film is peeled off, the peeling is not at the interface between the first release film and the functional film but at the interface between the functional film and the second release film. The present invention is preferably applied to a functional film having the thickness.

<Polarizing film>
As the optical film, a polarizing film is preferably used. When using a polarizing film, it is preferable to use a polarizing film having a thickness (total thickness) of 60 μm or less. The thickness of the polarizing film may be 55 μm or less, further 50 μm or less from the viewpoint of thinning. As the configuration of the polarizing film, for example, (1) a configuration in which protective films are laminated on both sides of the polarizer in this order (both protective polarizing films), and (2) a protective film is laminated only on one side of the polarizer. Structure (single protective polarizing film).

≪Polarizer≫
A polarizer using a polyvinyl alcohol-based resin is used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable.

A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol in an aqueous iodine solution and stretching it 3 to 7 times the original length. If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

The thickness of the polarizer is preferably 10 μm or less from the viewpoint of thinning, more preferably 8 μm or less, further 7 μm or less, and further preferably 6 μm or less. On the other hand, the thickness of the polarizer is preferably 2 μm or more, and more preferably 3 μm or more. Such a thin polarizer has less thickness unevenness, excellent visibility, and less dimensional change, and therefore excellent durability against thermal shock. On the other hand, since a polarizing film including a polarizer having a thickness of 10 μm or less has a significantly low elasticity (elastic modulus), the release film and the pressure-sensitive adhesive layer are peeled off when the release film is peeled off in the sheet-to-panel method. Peeling is particularly likely to occur at the interface between the polarizing film and the surface protective film rather than at the interface of the present invention, and the present invention is particularly suitable for the polarizing film.

As a thin polarizer, typically,
Patent No. 4751486,
Japanese Patent No. 4751481,
Patent No. 4815544,
Patent No. 5048120,
International Publication No. 2014/077599 pamphlet,
International Publication No. 2014/077636 Pamphlet,
And the thin polarizers obtained from the production methods described therein.

The polarizer has an optical characteristic expressed by a single transmittance T and a polarization degree P of the following formula P> − (10 ^0.929T-42.4 −1) × 100 (where T <42.3), Or it is preferable to be comprised so that the conditions of P> = 99.9 (however, T> = 42.3) may be satisfied. A polarizer configured so as to satisfy the above-described conditions uniquely has performance required as a display for a liquid crystal television using a large display element. Specifically, the contrast ratio is 1000: 1 or more and the maximum luminance is 500 cd / m ² or more. As other uses, for example, it is bonded to the viewing side of the organic EL cell.

As the thin polarizer, among the production methods including the step of stretching in the state of a laminate and the step of dyeing, Patent No. 4751486, Patent, in that it can be stretched at a high magnification and the polarization performance can be improved. What is obtained by the manufacturing method including the process of extending | stretching in a boric-acid aqueous solution as described in the 4751481 specification and the patent 4815544 specification is preferable, and it describes especially in the patent 4751481 specification and the patent 4815544 specification. What is obtained by the manufacturing method including the process of extending | stretching in the air auxiliary before extending | stretching in the boric-acid aqueous solution which has this is preferable. These thin polarizers can be obtained by a production method including a step of stretching a polyvinyl alcohol-based resin (hereinafter also referred to as PVA-based resin) layer and a stretching resin base material in a laminated state and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching by being supported by the stretching resin substrate.

≪Protective film≫
As the material constituting the protective film, a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) And polymers based on polycarbonate and polycarbonate. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like can also be mentioned as examples of the polymer forming the protective film. These protective films are usually bonded to the polarizer by an adhesive layer.

In addition, 1 or more types of arbitrary appropriate additives may be contained in the protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, an anti-coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When content of the said thermoplastic resin in a protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has cannot fully be expressed.

As the protective film, a retardation film, a brightness enhancement film, a diffusion film, and the like can also be used.

The thickness of the protective film can be determined as appropriate, but in general, it is preferably 5 to 50 μm, more preferably 5 to 45 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. Is preferred.

A functional layer such as a hard coat layer, an antireflection layer, an antisticking layer, a diffusion layer or an antiglare layer can be provided on the surface of the protective film where the polarizer is not adhered. In addition, the hard coat layer, the antireflection layer, the antisticking layer, the diffusion layer, the antiglare layer, and other functional layers can be provided on the protective film itself, or can be provided separately from the protective film. it can.

<Intervening layer>
The protective film and the polarizer are laminated via an intervening layer such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer). At this time, it is desirable that the both are laminated without an air gap by an intervening layer. In addition, also in FIG. 2, the intervening layer of polarizer a1 and protective film a2 is not shown.

The adhesive layer is formed with an adhesive. The type of the adhesive is not particularly limited, and various types can be used. The adhesive layer is not particularly limited as long as it is optically transparent. Examples of the adhesive include water-based, solvent-based, hot-melt-based, active energy ray-curable types, and the like. Or an active energy ray hardening-type adhesive agent is suitable.

Examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex systems, and water-based polyesters. The water-based adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of solid content.

The active energy ray curable adhesive is an adhesive that cures by an active energy ray such as an electron beam or ultraviolet rays (radical curable type, cationic curable type), for example, in an electron beam curable type or an ultraviolet curable type. Can be used. As the active energy ray curable adhesive, for example, a photo radical curable adhesive can be used. When the photo radical curable active energy ray curable adhesive is used as an ultraviolet curable adhesive, the adhesive contains a radical polymerizable compound and a photo polymerization initiator.

The adhesive coating method is appropriately selected depending on the viscosity of the adhesive and the target thickness. Examples of coating methods include reverse coaters, gravure coaters (direct, reverse and offset), bar reverse coaters, roll coaters, die coaters, bar coaters, rod coaters and the like. In addition, for coating, a method such as a dapping method can be appropriately used.

In addition, when the water-based adhesive or the like is used, the adhesive is preferably applied so that the finally formed adhesive layer has a thickness of 30 to 300 nm. The thickness of the adhesive layer is more preferably 60 to 150 nm. On the other hand, when an active energy ray curable adhesive is used, the thickness of the adhesive layer is preferably 0.2 to 20 μm.

In addition, in laminating | stacking a polarizer and a protective film, an easily bonding layer can be provided between a protective film and an adhesive bond layer. The easy adhesion layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins can be used alone or in combination of two or more. Moreover, you may add another additive for formation of an easily bonding layer. Specifically, a stabilizer such as a tackifier, an ultraviolet absorber, an antioxidant, and a heat resistance stabilizer may be used.

The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive. Various pressure-sensitive adhesives can be used as the pressure-sensitive adhesive, such as rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives, polyvinylpyrrolidone-based pressure-sensitive adhesives, Examples include acrylamide-based adhesives and cellulose-based adhesives. An adhesive base polymer is selected according to the type of the adhesive. Among the pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and are excellent in weather resistance and heat resistance. The

The undercoat layer (primer layer) is formed to improve the adhesion between the polarizer and the protective film. The material constituting the primer layer is not particularly limited as long as the material exhibits a certain degree of strong adhesion to both the base film and the polyvinyl alcohol-based resin layer. For example, a thermoplastic resin excellent in transparency, thermal stability, stretchability, etc. is used. Examples of the thermoplastic resin include an acrylic resin, a polyolefin resin, a polyester resin, a polyvinyl alcohol resin, or a mixture thereof.

<Other functional films>
As a functional film of this invention, the thing similar to the protective film illustrated by the term of the said polarizing film can be used. As the functional film, the film (functional base film) can be used alone, or a functional base film provided with a surface treatment layer on one side or both sides as shown in FIG. 5 can be used. . Examples of the surface treatment layer include functional layers such as a hard coat layer, an antireflection layer, an antisticking layer, a diffusion layer, and an antiglare layer, which have been described as being applicable to the protective film of the polarizing film. The thickness of the functional base film can be appropriately determined within a range of 110 μm or less, but generally it is preferably 10 to 110 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. Is preferably 25 to 105 μm. The surface treatment layer is preferably 25 μm or less, and more preferably 15 μm or less.

<Adhesive layer for functional film>
For the formation of the functional film pressure-sensitive adhesive layer, an appropriate pressure-sensitive adhesive can be used, and the type thereof is not particularly limited. Adhesives include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, Examples thereof include cellulose-based pressure-sensitive adhesives.

Among these pressure-sensitive adhesives, those having excellent optical transparency, suitable wettability, cohesiveness, and adhesive pressure characteristics, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used as one exhibiting such characteristics.

As a method for forming the pressure-sensitive adhesive layer for functional films, for example, the pressure-sensitive adhesive is applied to a release film (separator or the like) from which the pressure-sensitive adhesive has been peeled off, and the polymerization solvent is dried and removed to form a pressure-sensitive adhesive layer. It is produced by a method of transferring to a film or a method of applying the pressure-sensitive adhesive to a polarizing film and drying and removing the polymerization solvent to form a pressure-sensitive adhesive layer on the polarizer. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be added as appropriate.

As the release film after the release treatment, a silicone release liner is preferably used. In the step of forming the pressure-sensitive adhesive layer by applying and drying the pressure-sensitive adhesive of the present invention on such a liner, an appropriate method may be adopted as appropriate according to the purpose. Preferably, a method of heating and drying the coating film is used. The heating and drying temperature is preferably 40 ° C to 200 ° C, more preferably 50 ° C to 180 ° C, and particularly preferably 70 ° C to 170 ° C. By setting the heating temperature within the above range, an adhesive having excellent adhesive properties can be obtained.

Appropriate time can be adopted as the drying time. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

Various methods are used as a method for forming the pressure-sensitive adhesive layer. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm. The thickness is preferably 2 to 50 μm, more preferably 2 to 40 μm, and still more preferably 5 to 35 μm.

<1st peeling film: When using for protection of the adhesive layer for functional films>
A 1st peeling film is used, for example when protecting the adhesive layer for functional films until it uses for practical use (refer FIG. 2, FIG. 3). As the first release film, the release film (separator or the like) used for forming the functional film pressure-sensitive adhesive layer can be used as it is as the first release film. The said 1st peeling film (release film) has a 1st base film. Examples of the constituent material of the first base film include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foamed sheets, metal foils, and the like. Although an appropriate thin leaf body such as a laminate can be mentioned, a plastic film is preferably used from the viewpoint of excellent surface smoothness.

The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer for functional films, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, Examples thereof include a vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

For the first base film of the first release film, if necessary, mold release and antifouling treatment with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, An antistatic treatment such as a coating type, a kneading type, or a vapor deposition type can also be performed. In particular, when the surface of the release film is appropriately subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment, the peelability from the functional film pressure-sensitive adhesive layer can be further enhanced. The thickness of the first base film of the first release film (release film) is designed so that the first bending resistance of the first release film is greater than the second bending resistance of the second release film. Is done.

<First release film, second release film: When used as a surface protective film>
A 1st peeling film and a 2nd peeling film can be used as a surface protection film, for example. When the functional film has a functional film pressure-sensitive adhesive layer on one side, the surface protective film can be used as the second release film on the other side (see FIGS. 2 and 3). Moreover, a surface protective film can be used as a 1st peeling film and a 2nd peeling film in both surfaces of a functional film (refer FIG. 4, FIG. 5).

The first and second release films (surface protective films) have first and second base films, respectively. As the first and second base films used for the surface protective film, film materials having isotropic properties or close to isotropic properties are selected from the viewpoints of inspection properties and manageability. Examples of the film material include polyester resins such as polyethylene terephthalate film, cellulose resins, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefins such as polyethylene and polypropylene. And transparent polymers such as acrylic resins and acrylic resins. Of these, polyester resins are preferred. The first and second substrate films can be used as a laminate of one or more film materials, and a stretched product of the film can also be used. The thicknesses of the first and second substrate films of the first and second release films (surface protective films) are such that the first bending resistance of the first peeling film is higher than the second bending resistance of the second release film. Designed to be large.

As the surface protective film, the first and second base films can be used as self-adhesive films, and those having the base film and the adhesive layer for the surface protective film can be used. From the viewpoint of protecting the functional film, it is preferable to use a surface protective film having a pressure-sensitive adhesive layer for the surface protective film.

The pressure-sensitive adhesive layer for the surface protective film used for laminating the surface protective film is, for example, a (meth) acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer. It is possible to appropriately select and use the pressure-sensitive adhesive. From the viewpoints of transparency, weather resistance, heat resistance and the like, an acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer is preferable. The thickness (dry film thickness) of the pressure-sensitive adhesive layer for the surface protective film is determined according to the required adhesive force. Usually, it is about 1 to 100 μm, preferably 5 to 50 μm.

The surface protective film (the surface opposite to the surface when the surface protective film pressure-sensitive adhesive layer is provided) is coated with a release treatment layer using a low-adhesive material such as silicone treatment, long-chain alkyl treatment, or fluorine treatment. Can be provided.

<Peeling of the first release film>
The film laminate of the present invention is obtained by laminating a functional film and a first release film and a second release film on both sides thereof, and is prepared in a sheet shape of a predetermined shape (step (1)). An example of the predetermined shape is a rectangular object. Subsequently, a 1st peeling film is peeled from the said film laminated body (process (2)). When peeling the first release film, the film laminate is fixed to the second release film side by, for example, adsorption, and the first release film can be peeled using a peeling roller (for example, (See JP-A-9-114384).

<Manufacture of optical display panel>
When the film laminate of the present invention has a functional film having a functional film pressure-sensitive adhesive layer (see, for example, FIGS. 2 and 3), the above step (1) and then step (2) The film laminate (for example, a functional film with a pressure-sensitive adhesive layer having a surface protective film as the second release film) from which the 1 release film has been peeled is bonded to one surface of the optical cell by the step (3). In step (3), the functional film pressure-sensitive adhesive layer side of the functional film is bonded to an optical cell to produce an optical display panel.

<Other optical layers>
When an optical film is used as the functional film of the present invention, the optical film can be used by being laminated with other optical layers in practical use. The optical layer is not particularly limited. For example, when a polarizing film is used as the optical film, for example, a reflection plate, a semi-transmission plate, a retardation plate (including a wave plate such as 1/2 or 1/4) is included. ), One or two or more optical layers that may be used for forming a liquid crystal display device such as a viewing angle compensation film and a brightness enhancement film.

The optical film in which the optical layer is laminated can also be formed by a method of laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that it is excellent in assembling work and can improve the manufacturing process of a liquid crystal display device or the like. For the lamination, an appropriate adhesive means such as a pressure-sensitive adhesive layer can be used. When adhering the polarizing film with the pressure-sensitive adhesive layer and other optical films, their optical axes can be arranged at an appropriate angle depending on the intended retardation characteristics and the like.

<Optical cell>
(Liquid crystal cell, liquid crystal display panel)
The liquid crystal cell has a structure in which a liquid crystal layer is sealed between a pair of substrates (a first substrate (viewing side surface) Pa and a second substrate (back surface) Pb) disposed to face each other. Although any type of liquid crystal cell can be used, it is preferable to use a vertical alignment (VA) mode or in-plane switching (IPS) mode liquid crystal cell in order to achieve high contrast. A liquid crystal display panel has a polarizing film bonded to one or both sides of a liquid crystal cell, and a drive circuit is incorporated as necessary.

Appropriate liquid crystal display devices such as a liquid crystal display device in which an optical film is disposed on one side or both sides of a liquid crystal cell or a backlight or a reflector used in an illumination system can be formed. In that case, the optical film of this invention can be installed in the single side | surface or both surfaces of a liquid crystal cell. When the optical films of the present invention are provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

(Organic EL cell, organic EL display panel)
An organic EL cell as another optical cell has a configuration in which an electroluminescent layer is sandwiched between a pair of electrodes. As the organic EL cell, for example, an arbitrary type such as a top emission method, a bottom emission method, a double emission method, or the like can be used. In the organic EL display panel, the optical film (polarizing film) of the present invention is bonded to the organic EL cell together with the retardation film, and a drive circuit is incorporated as necessary.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples shown below. In addition, all the parts and% in each example are based on weight. The room temperature standing conditions not specifically defined below are all 23 ° C. and 65% RH.

<Preparation of polarizing film>
(Production of polarizer)
One side of an amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and Tg of 75 ° C. is subjected to corona treatment. Alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. An aqueous solution containing 9: 1 ratio of the trade name “Gosefimer Z200”) was applied and dried at 25 ° C. to form a PVA-based resin layer having a thickness of 11 μm, thereby preparing a laminate.
The obtained laminate was uniaxially stretched in the longitudinal direction (longitudinal direction) 2.0 times between rolls having different peripheral speeds in an oven at 120 ° C. (air-assisted stretching process).
Next, the laminate was immersed in an insolubilization bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Subsequently, it was immersed in a dyeing bath having a liquid temperature of 30 ° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 parts by weight of iodine was blended with 100 parts by weight of water, and immersed in an aqueous iodine solution obtained by blending 1.0 part by weight of potassium iodide (dyeing treatment). .
Subsequently, it was immersed for 30 seconds in a crosslinking bath having a liquid temperature of 30 ° C. (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water). (Crosslinking treatment).
Thereafter, the laminate was immersed in a boric acid aqueous solution (an aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70 ° C. However, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) so that the total stretching ratio was 5.5 times (in-water stretching treatment).
Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 30 ° C. (cleaning treatment).
As a result, an optical film laminate including a polarizer having a thickness of 5 μm was obtained.

(Protective film)
Protective film 1: A film having a total thickness of 50 μm obtained by applying a low-reflection surface treatment having a thickness of 10 μm to one side of a 40 μm-thick triacetyl cellulose film.
Protective film 2: A triacetyl cellulose film having a thickness of 40 μm was used.

(Adhesive applied to protective films 1 and 2)
An ultraviolet curable adhesive was prepared by mixing 40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO), and 3 parts by weight of a photoinitiator “IRGACURE 819” (manufactured by BASF).

<Production of single-protective polarizing film A1>
While applying the ultraviolet curable adhesive to the surface of the polarizer of the optical film laminate so that the thickness of the adhesive layer after curing is 1 μm, the protective film 1 (which has been subjected to a low reflection surface treatment). After bonding, the adhesive was cured by irradiating with ultraviolet rays as active energy rays. Ultraviolet irradiation is performed using a gallium-encapsulated metal halide lamp, an irradiation device: Fusion UV Systems, Inc. Light HAMMER 10, Inc., bulb: V bulb, peak illuminance: 1600 mW / cm ² , integrated irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm) ), And the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Subsequently, the amorphous PET base material was peeled off to produce a piece protective polarizing film A using a thin polarizer. The optical properties of the obtained piece-protecting polarizing film A1 were a single transmittance of 42.8% and a degree of polarization of 99.99%. The obtained piece-protecting polarizing film has a thickness of 56 μm.

<Preparation of both protective polarizing films A2>
(Preparation of a polarizer having a thickness of 23 μm)
A polyvinyl alcohol film having an average polymerization degree of 2400 and a saponification degree of 99.9 mol% and a thickness of 75 μm was immersed in warm water at 30 ° C. for 60 seconds to swell. Next, the film was dyed while being immersed in an aqueous solution of 0.3% concentration of iodine / potassium iodide (weight ratio = 0.5 / 8) and stretched to 3.5 times. Then, it extended | stretched so that the total draw ratio might be 6 times in 65 degreeC borate ester aqueous solution. After extending | stretching, it dried for 3 minutes in 40 degreeC oven, and obtained the PVA-type polarizer (23 micrometers in thickness).
After the protective film 1 is bonded to one side of the polarizer via an ultraviolet curable adhesive in the same manner as described above, the other side is subjected to the ultraviolet curable adhesive in the same manner as described above. The protective film 2 was bonded together. The optical properties of the obtained both protective polarizing films A2 were a transmittance of 42.8% and a degree of polarization of 99.99%. Both protective polarizing films A2 have a thickness of 115 μm.

<Single transmittance T and polarization degree P of polarizer>
The single transmittance T and the polarization degree P of the obtained polarizing film were measured using a spectral transmittance measuring device with an integrating sphere (Dot-3c of Murakami Color Research Laboratory).
The degree of polarization P is the transmittance when two identical polarizing films are overlapped so that their transmission axes are parallel (parallel transmittance: Tp), and overlapped so that their transmission axes are orthogonal to each other. It is calculated | required by applying the transmittance | permeability (orthogonal transmittance | permeability: Tc) at the time of combining to the following formula | equation. Polarization degree P (%) = {(Tp−Tc) / (Tp + Tc)} ^1/2 × 100
Each transmittance is represented by a Y value obtained by correcting visibility with a two-degree field of view (C light source) of JIS Z8701, with 100% of the completely polarized light obtained through the Granteller prism polarizer.

<Preparation of adhesive>
In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 100 parts of butyl acrylate, 3 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate and 2,2′-azobisisobutyrate A solution was prepared by adding 0.3 parts of ronitrile with ethyl acetate. Next, the solution was stirred while blowing nitrogen gas and reacted at 55 ° C. for 8 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight of 2.2 million. Furthermore, the acrylic polymer solution which added ethyl acetate to the solution containing this acrylic polymer and adjusted solid content concentration to 30% was obtained.

As a cross-linking agent, 100 parts by weight of the solid content of the acrylic polymer solution is a cross-linking agent mainly composed of a compound having an isocyanate group of 0.5 part (trade name “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.). And 0.075 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KMB-403”) as a silane coupling agent in this order, Was prepared.

<Functional film: TAC film>
A3: A triacetyl cellulose film having a thickness of 80 μm was prepared.
A4: A triacetyl cellulose film having a thickness of 25 μm was prepared.

<Functional film: Film having low reflection surface treatment layers on both sides>
A5: Two low-reflection surface-treated films (thickness 50 μm) of the protective film 1 are prepared, and the surfaces of the film that have not been subjected to the low-reflection surface treatment are UV-cured adhesive in the same manner as described above. A film (double-sided AR film) in which a low reflection surface treatment layer was provided on both sides was prepared by bonding through (thickness 5 μm). The thickness of the double-sided AR film is 105 μm.

Example 1
<Lamination of surface protective film>
A surface protective film (second release film, trade name RP108C manufactured by Nitto Denko Corporation) was provided on the protective film 1 side of the piece protective polarizing film A1. As the surface protective film, a polyester resin film (second base film) having a thickness of 25 μm and a pressure-sensitive adhesive layer having a thickness of 15 μm (corresponding to a pressure-sensitive adhesive layer for a surface protective film) was used.

<Formation of pressure-sensitive adhesive layer with release film (first release film)>
Thickness after drying on the surface of a release film (separator) made of a polyethylene terephthalate film (first substrate film thickness 50 μm: trade name Diafoil MRF manufactured by Mitsubishi Plastics) from which the above adhesive solution was peeled. Was applied to a thickness of 20 μm and dried to form an adhesive layer (corresponding to an adhesive layer for a polarizing film (functional film)). Next, the pressure-sensitive adhesive layer is bonded to the polarizer side of the single protective polarizing film A having a surface protective film, and the film laminate of the present invention (see FIG. 3: adhesive having a release film and a surface protective film). A polarizing film with an agent layer) was produced.

Comparative Examples 1 and 2 and Reference Examples 1 to 3
In Example 1, the kind of polarizing film, the thickness of the second base film of the surface protective film used as the second release film, and the first base film thickness of the release film used as the first release film are shown in Table 1. A film laminate was produced in the same manner as in Example 1 except that the change was made as shown in FIG.

Example 2
<Lamination of surface protective film>
Surface protective films (first and second release films) were provided on both surfaces of the functional film A3 (80 μm thick TAC film).
The first release film has a 100 μm thick polyester resin film (first base film) as a surface protective film and a 15 μm thick adhesive layer (corresponding to an adhesive layer for the surface protective film). (Trade name RP108C, manufactured by Nitto Denko Corporation).
The second release film has a 25 μm thick polyester resin film (second base film) as a surface protective film and a 15 μm thick adhesive layer (corresponding to the adhesive layer for the surface protective film). (Trade name RP108C, manufactured by Nitto Denko Corporation).

Examples 3 to 5 and Comparative Examples 3 to 6
In Example 2, except that the types of functional films, the thicknesses of the first and second substrate films of the surface protective film used as the first and second release films, and the materials were changed as shown in Table 1. A film laminate was produced in the same manner as in Example 2. In Example 5 and Comparative Example 6, as a surface protective film, a polyethylene resin film (first base film or second base film) having a thickness of 240 μm or 60 μm and a pressure-sensitive adhesive layer (surface protective film) having a thickness of 15 μm are used. (Corresponding to the pressure-sensitive adhesive layer for use) (trade name HR6010 manufactured by Nitto Denko Corporation).

The following evaluations were performed on the film laminates and their constituent materials obtained in the above examples, comparative examples and reference examples. The results are shown in Table 1.

<Flexibility test>
The bending resistance of the first and second release films was measured by the following method.
No. made by Yasuda Seiki Seisakusho. A 476 cantilever type flexibility tester was used. Moreover, in this test, in order to eliminate the influence of static electricity, the sample used for the test was appropriately discharged.
About each film laminated body, the rectangular object F (sample) of 20 mm x 150 mm was prepared. The top portion is flat (20 mm × 150 mm: the same size as the sample), has a 45 ° slope at one end of the long side, and is placed so as to fit on the top surface of a smooth SUS plate base 41 having a trapezoidal cross section (FIG. 6). reference).
The sample was gently slid and moved to the slope side at an extrusion speed of 10 mm / sec (1). The sample stopped moving at the point where the tip of the sample first contacted the slope (2). The distance L (mm) by which the sample moved while the top was flat was measured.
The bending resistance (mm) was measured three times for each of the two patterns when the first surface was the upper side and the second surface was the upper side for each sample (total 12 samples). And the arithmetic average value thereof.

<Measurement of peel force>

The film laminates obtained in Examples, Comparative Examples and Reference Examples were cut into 25 mm × 100 mm, and the double-sided tape was peeled off from the first release film and the second release film on the side where the peel force was not measured. (Nitto Denko Co., Ltd., double-sided tape No. 511) was attached to non-alkali glass having a thickness of 0.5 mm each. Cellophane tape is attached to the short side edge of the polarizing film with the pressure-sensitive adhesive layer bonded to the alkali-free glass, and the first release film or the second release film is 180 ° using Tensilon after peeling off only the start part in advance. Peeling was performed in parallel with the long side direction of the film at a speed of 0.3 m / min. The peeling force of the 1st peeling film and the 2nd peeling film was measured, respectively. The results are shown in Table 1.

<Pickup test>
About the film laminated body obtained by the Example, the comparative example, and the reference example, it cut | judged to 150 mm x 150 mm, and was made into the single wafer state (sample).
With the first release film side of the sample on the upper side and the second release film side on the lower side, the second release film side (all) of the sample is made with a double-sided tape (double-sided tape No. 511 manufactured by Nitto Denko Corporation). Fixed on glass. On the other hand, a pickup roller was prepared by winding a double-sided tape having a width of 5 mm (manufactured by Nitto Denko Corporation, double-sided tape No. 511) around a roller having a diameter of 45 mm. Next, the roller having a diameter of 45 mm was moved in parallel to the diagonal direction of the sample using a pickup roller from the edge end portion of the sample fixed to the glass. The number of times the operation was performed 10 times and peeled from the first release film is shown in Table 1 as “number of times / 10”.

<Floating test>
About the film laminated body obtained by the Example, the comparative example, and the reference example, it cut | judged to 25 mm x 100 mm, and was made into the single wafer state (sample).
With the first release film side of the sample on the upper side and the second release film side on the upper side, a double-sided tape (double-sided tape No. 511 manufactured by Nitto Denko Corporation) is used, and the second release film side of the sample (end in the longitudinal direction) A part of 20 to 100 mm from the part) was affixed to the glass and fixed on the glass. That is, the portion of 0 to 20 mm from the end in the longitudinal direction of the sample was in a floating state.
Next, a cellophane tape having a width of 25 mm was applied to the end of the sample fixed to the glass (the floating side) on the test piece, and then 300 mm / min in the longitudinal direction of the sample at an angle of 30 °. The cellophane tape was pulled at a tensile speed.
When the above operation was performed and the first release film was not peeled off, it is shown as “Pass” in Table 1. When the 1st peeling film peeled, the distance (mm) pulled was shown in Table 1.

In Table 1, PET represents polyethylene terephthalate, and PE represents polyethylene.

F Film-laminated optical film in a single wafer state A Functional film A ′ Polarizing film a1 Polarizer a2 Protective film B Functional film adhesive layer 1 First release film 11 First substrate film 12 Surface protective film adhesive layer 2 2nd peeling film 21 2nd base film 22 Adhesive layer for surface protection films

Claims

A first release film having a first substrate film, a functional film and a second release film having a second substrate film are laminated in this order,
The first release film is peeled off before the second release film,
The functional film has a thickness of 110 μm or less, and
The film laminated body characterized by the 1st bending softness (mm) in the bending softness test of a 1st peeling film being larger than the 2nd bending softness (mm) in the bending softness test of a 2nd peeling film.
The film laminate according to claim 1, wherein a difference between the first bending resistance (mm) and the second bending resistance (mm) is 10 mm or more.
The film laminate according to claim 1 or 2, wherein the peel force (1) of the first peel film is equal to or greater than the peel force (2) of the second peel film.
The film laminate according to any one of claims 1 to 3, wherein a thickness of the first base film is larger than a thickness of the second base film.
The film laminate according to any one of claims 1 to 4, wherein the thickness of the first base film is 40 µm or more.
6. The optical film according to claim 1, wherein the second base film has a thickness of 35 μm or less.
The film laminate according to any one of claims 1 to 6, wherein the functional film is an optical film.
The film laminate according to claim 7, wherein the optical film has a polarizing film.
The film laminate according to claim 8, wherein the polarizing film has a polarizer having a thickness of 10 μm or less.
The film laminate according to claim 8 or 9, wherein the polarizing film is a single-protective polarizing film having a protective film only on one side of a polarizer.
The film laminate according to any one of claims 7 to 10, wherein the optical film has a surface treatment layer on one side or both sides.
The film laminate according to any one of claims 1 to 11, wherein each of the first release film and the second release film is a surface protective film.
The functional film has a functional film pressure-sensitive adhesive layer on the side on which the first release film is provided, and the second release film is a surface protective film. Film laminate.
The film laminate according to claim 12 or 13, wherein the surface protective film has a pressure-sensitive adhesive layer for the surface protective film, and is laminated on the functional film via the pressure-sensitive adhesive layer.
The film laminate according to claim 12 or 13, wherein the surface protective film is a self-adhesive film.
A method for peeling a first release film, comprising peeling off the first release film from the film laminate according to any one of claims 1 to 15.
Preparing the film laminate according to any one of claims 13 to 15 (1),
A step (2) of peeling the first release film from the film laminate, and
The manufacturing method of an optical display panel which has the process (3) which affixes the side of the adhesive layer for functional films of the said film laminated body from which the said 1st peeling film peeled to the one surface of an optical cell.
The method for manufacturing an optical display panel according to claim 17, wherein the optical cell is a liquid crystal cell or an organic EL cell.