TWI681205B - Film laminate, peeling method of first peeling film, and method of manufacturing optical display panel - Google Patents

Abstract

The present invention is a monolithic film laminate formed by sequentially laminating a first release film having a first base film, a functional film, and a second release film having a second base film, and the first release film It is peeled earlier than the second peeling film. The thickness of the functional film is 110 μm or less, and the first bending stiffness (mm) of the first peeling film in the bending rigidity test is greater than that of the second peeling film in the bending rigidity test The second bending stiffness (mm). The laminate of the present invention can easily peel off the first peeling film (the peeling film on the side where the peeling was performed first) even when a thin functional film is used.

Description

Film laminate, peeling method of first peeling film, and method of manufacturing optical display panel

The present invention relates to a monolithic film laminate formed by sequentially laminating a first release film, a functional film, and a second release film.

In addition, the present invention relates to a peeling method of the first peeling film of the film laminate. Furthermore, the present invention relates to a method of manufacturing an optical display panel using the film laminate.

The functional film is protected by a peeling 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 provided with an adhesive layer attached to the adhesive layer of an optical unit such as a liquid crystal cell on one side, the release film is usually temporarily adhered to the adhesive layer (Release film) until applied. On the other hand, on the other side of the optical film, another release film (surface protection film) is temporarily adhered. Such an optical film with an adhesive layer with a release film and a surface protection film can be applied to an optical display panel, but at this time, the adhesive layer exposed by peeling off the release film from the optical film with an adhesive layer is first attached Close to the optical unit. The surface protective film is directly attached to the optical film with the adhesive layer attached.

For the above bonding, for example, there is a method of bonding the adhesive layer exposed through the release film to the optical film with the adhesive layer rolled out from the winding body and being transported to the surface of the optical unit (hereinafter, also It is called "roller-to-panel method"; Patent Document 1). In addition, there is a method of attaching the adhesive layer exposed to the adhesive layer in a single-piece state through the release film to the optical unit (hereinafter, also referred to as "sheet-to-panel method").

On the other hand, image display devices, such as liquid crystal display devices, have been developed to be thinner, and the polarizing film is also required to be thinner. Therefore, the polarizing element is also becoming thinner (Patent Document 2). Moreover, the thinning of the polarizing film can be performed by using a single-sided protective polarizing film in which a protective film is provided only on one side of the polarizing element and no protective film is provided on the other single side. The single-sided protective polarizing film has one less protective film than the two-sided protective polarizing films provided with protective films on both sides of the polarizing element, so a thinner type can be achieved.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 4404043

[Patent Document 2] Specification of Japanese Patent No. 4551481

When peeling off the release film from the above-mentioned optical film with an adhesive layer with a release film and a surface protection film (for example, a polarizing film with an adhesive layer), the surface of the optical film with an adhesive layer is usually protected Release the release film with the film side fixed. However, in recent years, the expectation that the surface protective film can be easily peeled without remaining a paste has increased, and the peeling force of the surface protective film has been continuously reduced. If it is before, from the viewpoint of the peeling order, it is more preferable to use the previously released release film and The surface protection film peeled off is designed in such a way that the peeling force is sufficiently reduced (easy to peel off). However, it is newly clarified that in recent years, it has been proposed that the peeling force of the surface protective film is not sufficiently large compared to the peeling force of the release film, or the peeling force of the surface protective film is designed to be smaller with an adhesive layer-attached optical film. Therefore, the following problem occurs: when peeling off the release film, it is not at the interface between the release film and the adhesive layer, but at the interface between the optical film (such as a polarizing film) and the surface protective film. The above-mentioned problem can be solved, for example, as long as the peeling force of the surface protective film and the peeling force of the release film are substantially the same. However, for the release film, in order to ensure the adhesion between the optical film and the optical unit, a peeling force of more than a certain level is required. Therefore, when the peeling force of the release film is designed to be approximately the same as the peeling force of the surface protective film, it cannot be It is required to reduce the adhesion between the optical film and the optical unit, or to reduce the peeling force of the surface protective film. It can be seen that the above-mentioned problems are particularly evident when the release film is peeled off from the single-layer polarizing film with an adhesive layer of a thin polarizing film having a specific thickness or less (for example, 60 μm or less) in the sheet-to-panel method.

An object of the present invention is to provide a film laminate which is a single piece having a first release film and a second release film on both sides of a functional film, and can be easily used even when a thin functional film is used Peel the first peeling film (the peeling film on the side where peeling was first performed).

In addition, an object of the present invention is to provide a peeling method for the first peeling film of the film laminate, and an object of the present invention is to provide a method for manufacturing an optical display panel using the film laminate.

The inventors of this case, after hard research, found that the following film laminates can be used The above-mentioned problems are solved to complete the present invention.

That is, the present invention relates to a film laminate, characterized in that it is a single layer formed by sequentially stacking a first release film having a first base film, a functional film, and a second release film having a second base film In sheet form, and the thickness of the above functional film is 110 μm or less, and the first bending stiffness (mm) of the first peeling film in the bending rigidity test is greater than the second bending stiffness (mm) of the second peeling film in the bending rigidity test .

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

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

In the film laminate, the thickness of the first base film is preferably greater 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 thickness of the second base film is preferably 35 μm or less.

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

As the above-mentioned optical film, a polarizing film can be used. The above-mentioned polarizing film can be preferably used in the case of a polarizing element having a thickness of 10 μm or less. In addition, the above-mentioned polarizing film can be preferably used in a case where a single-sided protective polarizing film having a protective film on one side of the polarizing element.

In addition, as the above-mentioned optical film, those having a surface treatment layer on one side or both sides are preferably used.

In the above film laminate, it is preferable to use a surface protective film for both the first release film and the second release film.

In the film laminate, in the case where the functional film is provided with the adhesive layer for the functional film on the side where the first release film is provided, the surface protective film may be preferably used as the second release film.

In the film laminate, the surface protective film may be one having an adhesive layer for a surface protective film, and the surface protective film may be laminated on the functional film through the adhesive layer. As the surface protection film, a self-adhesive film can be used.

Furthermore, the present invention relates to a method for peeling a first peeling film, characterized in that the first peeling film is peeled from the film laminate.

In addition, the present invention relates to a method of manufacturing an optical display panel, comprising: the step (1) of preparing the film laminate; The step (2) of peeling the first release film from the film laminate; and the step of bonding the side of the adhesive layer for the functional film of the film laminate with the first release film attached to one surface of the optical unit (3 ).

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

The film lamination system of the present invention uses a first release film (the release film first peeled off from the film laminate) and a second release film (the release film peeled off after the first release film is peeled off) on both sides of the functional film, and The bending rigidity (mm) of the first peeling film in the bending rigidity test is greater than that of the second peeling film. Considering the design of the film laminate, the shear force in the cross-sectional direction of the functional film when peeling the first peeling film is greatly increased compared to the interface between the functional film and the second peeling film. As a result, in the case where the thickness of the functional film is 110 μm or less and the toughness (elastic modulus) is weak (and the peeling force of the second peeling film is smaller than the peeling force of the first peeling film), It is also possible to easily peel the first peeling film from the monolithic film laminate in the sheet-to-panel system without peeling off the interface between the functional film and the second peeling film.

1‧‧‧The first release film

2‧‧‧Second peeling film

11‧‧‧The first substrate film

12‧‧‧Adhesive layer for surface protection film

21‧‧‧Second substrate film

22‧‧‧Adhesive layer for surface protection film

41‧‧‧SUS pallet

A‧‧‧Functional film

A'‧‧‧ Polarizing film

a1‧‧‧ Polarizing element

a2‧‧‧Protection film

B‧‧‧Adhesive layer for functional film

F‧‧‧Single film optical film

L‧‧‧Distance

1 is a schematic cross-sectional view of a monolithic film laminate of the present invention.

2 is a schematic cross-sectional view of a single-layer film laminate in another embodiment of the present invention.

3 is a schematic cross-sectional view of a monolithic film laminate in another embodiment of the present invention.

4 is a schematic cross-sectional view of a monolithic film laminate in another embodiment of the present invention.

5 is a schematic cross-sectional view of a single-layer film laminate in another embodiment of the present invention.

Fig. 6 is a schematic diagram showing bending rigidity in a bending rigidity 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. The film laminate F is formed by sequentially stacking the first release film 1, the functional film A, and the second release film 2.

2 and 3 are provided with a functional film adhesive layer B on one side of the functional film A, a first release film 1 is provided on the functional film adhesive layer B, and a second side is provided on the other single side of the functional film A 2 Peel off film 2. The first release film 1 has a first base film, and the second release film 2 has a second base film.

In the aspect of FIGS. 2 and 3, the first release film 1 is used as an adhesive layer B for protecting the functional film until it is used as a practical release film. The first release film 1 has a first base film. In addition to this, for example, in order to improve the releasability from the adhesive layer B for functional films, the adhesive layer B for functional films may be bonded to the first base film A peeling treatment layer and the like (not shown) are provided on the side. In addition, when the first base film does not include a peeling treatment layer, the thickness of the first base film corresponds to the thickness of the first release film 1.

On the other hand, in the aspect of FIGS. 2 and 3, the second release film 2 can be used as a surface protection film. The second release film 2 (surface protection film) described in FIGS. 2 and 3 can be exemplified by the case where the second base film 21 and the adhesive layer 22 for the surface protection film are provided. In FIGS. 2 and 3, the surface protection film adhesive layer 22 side of the second release film 2 is bonded to the functional film A. In addition, FIG. 1 conceptually shows the case where the second release film 2 is a self-adhesive film. In the case where the second release film 2 is a self-adhesive film, the The thickness of the adhesive film corresponds to the thickness of the second base film.

FIG. 3 shows a case where the functional film A is a single-sided protective polarizing film having a protective film a2 on one side of the polarizing element a1. In addition, FIG. 3 exemplifies the case where the polarizing element a1 of the single-sided protective polarizing film has the adhesive layer B for the functional film, but the single-sided protective polarizing film may also have the functional film adhesive on the side of the protective film a2 Agent layer B configuration. In addition, as the functional film A of FIG. 2, for example, various optical films can be used, and on both sides of the polarizing element a1, both sides of the protective film a2 can be used to protect the polarizing film.

FIGS. 4 and 5 show a case where 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 single side.

In the aspect of FIGS. 4 and 5, the case where the first release film 1 has the first base film 11 and the adhesive layer 12 for the surface protection film is exemplified. In FIGS. 4 and 5, the surface protection film adhesive layer 12 side of the first release film 1 is bonded to the functional film A. On the other hand, in the aspect of FIGS. 4 and 5, the case where the second release film 2 has the second base film 21 and the adhesive layer 22 for the surface protection film is the same as that in FIGS. 2 and 3.

In FIG. 5, it is illustrated that the functional film A has a surface treatment layer a4 on both sides of the functional base film a3. In addition, as the functional film A of FIG. 5, for example, various optical films can be used, and those having a surface treatment layer a4 only on one side of the functional base film a3 can be used.

The film lamination system of the present invention uses the first bending stiffness in the bending rigidity test of the first release film 1 (mm) is larger than the second bending stiffness (mm) in the bending rigidity test of the second peeling film 2 to select the first peeling film and the second peeling film. The first bending stiffness (mm) and the second bending stiffness (mm) are preferably 10 mm or more, and more preferably 20 mm or more in terms of the stability of the peel accuracy (in the pickup test). Furthermore, it is preferably 30 mm or more.

Both the first peeling film 1 and the second peeling film 2 are to be finally peeled. The peeling force (1) of the first peeling film 1 and the peeling force (2) of the second peeling film 2 are preferably designed as Better peeling force. For example, in the aspect of FIGS. 2 and 3, the peeling force (1) is the peeling force of the first peeling film 1 to the adhesive layer B for the functional film. In the aspect of FIGS. 4 and 5, the peeling force ( 1) The peeling force of the first peeling film 1 to the functional film A. The peeling force (2) is the peeling force of the second peeling film 2 to the functional film A.

The peeling force (1) is preferably 0.03 N/25 mm or more from the viewpoint of preventing the end portion from hanging during processing. Furthermore, it is preferably 0.05 to 0.5 N/25 mm, and more preferably 0.1 to 0.3 N/25 mm. In addition, regarding the peeling force (2), from the viewpoint of easy peeling, it is preferably 0.2 N/25 mm or less, more preferably 0.01 to 0.1 N/25 mm, and still more preferably 0.01 to 0.05 N/25 mm.

The film laminate F of the present invention can be preferably used when the peeling force (1) of the first peeling film 1 is equal to or greater than the peeling force (2) of the second peeling film 2 described above. In particular, it can be preferably used in the case where the above-mentioned peeling force (1) is greater than the above-mentioned peeling force (2). The film laminate F of the present invention has a value {peeling force (1)/peeling force (2)} of 1.1 times or more, and further 1.5 times or more when the value of the peeling force (1) relative to the peeling force (2) The situation is better.

In the film laminate F of the present invention, the thickness of the first base film of the first release film 1 is preferably greater than the thickness of the second base film of the second release film 2. The bending stiffness of the film substrate is affected by the film thickness, and the greater the film thickness, the greater the bending stiffness. Therefore, by designing the thickness of the first base film to be greater than the thickness of the second base film, the first bending stiffness of the first peeling film can be adjusted to be greater than the second bending stiffness of the second peeling film. Especially when the first base film and the second base film are the same forming material, it is easy to adjust the bending stiffness by the above thickness.

Moreover, the adhesive layer for surface protection film etc. used as various treatment layers, such as a peeling treatment layer in the 1st and 2nd peeling film, or a surface protection film hardly affects bending rigidity. Therefore, the first bending stiffness of the first release film depends on the material and thickness of the first base film, and the second bending stiffness of the second release film depends on 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 still more 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, and more preferably 10 to 100 μm.

<functional film>

Functional films are various films that can be used according to the field in various fields. For example, in the optical field, optical films such as polarizing films, transparent protective films, retardation films, antireflection films, brightness enhancement films, and diffusion films can be used.

The functional film system has a thickness (total thickness) of 110 μm or less. 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 less than 110μm In the sheet-to-panel mode, when the first peeling film is peeled off, it is not at the interface between the first peeling film and the functional film, but at the interface between the functional film and the second peeling film, the present invention can be It is preferably applied to the functional film of this thickness.

<polarizing film>

As the above-mentioned optical film, a polarizing film can be suitably used. When a polarizing film is used, it is preferable to use a polarizing film having a thickness (total thickness) of 60 μm or less. Regarding the thickness of the polarizing film, from the viewpoint of thinning, those having a thickness of 55 μm or less and further 50 μm or less can be used. In addition, as a configuration of the polarizing film, for example, (1) a structure in which protective films are sequentially laminated on both sides of the polarizing element (both sides protecting polarizing films), (2) a protective film is only provided on a single area layer of the polarizing element The structure (single-sided protective polarizing film), etc.

≪Polarizing element≫

As the polarizing element, those using polyvinyl alcohol resins can be used. As the polarizing element, for example, a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, or the like can be adsorbed with iodine or a dichroic dye. The dichroic substance is uniaxially stretched, and the polyene-based alignment film such as polyvinyl alcohol dehydration treatment or polyvinyl chloride dehydrochlorination treatment etc. Among these, a polarizing element including a dichroic substance such as a polyvinyl alcohol-based film and iodine is preferable.

The polarizing element in which the polyvinyl alcohol-based film is dyed with iodine and uniaxially stretched can be produced, for example, by immersing the polyvinyl alcohol in an aqueous solution of iodine for dyeing and extending to 3~ the original length 7 times. It may contain boric acid, zinc sulfate, zinc chloride, etc. as required, or it may be impregnated in In aqueous solutions such as potassium iodide. Furthermore, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. The polyvinyl alcohol-based film can be washed with water to clean the dirt or anti-blocking agent on the surface of the polyvinyl alcohol-based film. In addition, the polyvinyl alcohol-based film can also be swelling to prevent uneven dyeing. Uneven effect. The stretching may be performed after dyeing with iodine, or it may be stretched while dyeing, or it may be dyed with iodine after stretching. It can also be extended in aqueous solutions or water baths such as boric acid or potassium iodide.

The thickness of the polarizing element is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less, and even more preferably 6 μm or less from the viewpoint of thinning. On the other hand, the thickness of the polarizing element is preferably 2 μm or more, and more preferably 3 μm or more. Such a thin polarizer has less thickness unevenness, excellent visibility, and little dimensional change, so it has excellent durability against thermal shock. On the other hand, the polarizing film including the polarizing element with a thickness of 10 μm or less significantly reduces the toughness (elastic modulus) of the film, so in the sheet-to-panel method, when the release film is peeled off, it is not due to the release film and adhesion The interface of the agent layer, but the interface between the polarizing film and the surface protective film is particularly prone to peeling, and the present invention is particularly suitable for the polarizing film.

As a thin polarizing element, representatively include Japanese Patent No. 4751486, Japanese Patent No. 4751481, Japanese Patent No. 4815544, Japanese Patent No. 5048120, and International Publication No. 2014/077599. , International Publication No. 2014/077636, The thin polarizing element described in or the like or the thin polarizing element obtained by the manufacturing method described in the above.

The polarizing element preferably has an optical characteristic expressed by a single transmittance T and a polarization degree P satisfying the following formula P>-(10 ^0.929T-42.4 -1)×100 (where T<42.3) , Or P≧99.9 (including T≧42.3). The polarizing element configured to satisfy the above conditions clearly has the 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 brightness is 500 cd/m ² or more. As another application, for example, it is attached to the viewing side of an organic EL (Electroluminescence) unit.

As the above-mentioned thin polarizing element, in the manufacturing method including the step of extending in the state of the laminate and the step of dyeing, it is also preferable to use such as Japanese patents in terms of extending at high magnification and improving polarizing performance. No. 4751486, Japanese Patent No. 4751481, and Japanese Patent No. 4815544, which are obtained by the manufacturing method including the step of extending in an aqueous solution of boric acid, particularly preferably through Japanese Patent No. 4751481, Japanese Patent 4815544 It is obtained by the method described in the No. specification including the step of performing the extension in advance in the air in an aqueous solution of boric acid in advance. These thin polarizing elements can be obtained by a manufacturing method including a step of extending a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a resin substrate for extension in a state of a laminate, and a step of dyeing. According to this manufacturing method, even if the PVA (Polyvinyl Alcohol, polyvinyl alcohol)-based resin layer is thin, it can be extended without defects such as breakage due to extension supported by the extension resin substrate.

≪Protection film≫

烯結構之聚烯烴、如乙烯-丙烯共聚物之聚烯烴系聚合物、氯乙烯系聚合物、尼龍或芳香族聚醯胺等醯胺系聚合物、醯亞胺系聚合物、碸系聚合物、聚醚碸系聚合物、聚醚醚酮系聚合物、聚苯硫醚系聚合物、乙烯醇系聚合物、偏二氯乙烯系聚合物、乙烯丁醛系聚合物、芳酯系聚合物、聚甲醛系聚合物、環氧系聚合物、或上述聚合物之摻合物等。該等保護膜通常係利用接著劑層而貼合於偏光元件。 As the material constituting the above-mentioned protective film, those having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropy and the like are preferred. For example, polyester-based polymers such as polyethylene terephthalate or polyethylene naphthalate, cellulose-based polymers such as diacetyl cellulose or triethyl cellulose, and polymethacrylate Acrylic polymers such as esters, styrene polymers such as polystyrene or acrylonitrile-styrene copolymers (AS (Acrylonitrile-Styrene, acrylonitrile-styrene) resins), and polycarbonate polymers. In addition, as an example of the polymer forming the above protective film, polyethylene, polypropylene, a ring system or a

Polyolefins with an olefin structure, polyolefin polymers such as ethylene-propylene copolymers, vinyl chloride polymers, nylon or aromatic polyamides, such as amide-based polymers, amide-imide polymers, and lanthanide-based polymers , Polyether ballast polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, ethylene butyraldehyde polymer, aryl ester polymer , Polyoxymethylene polymer, epoxy polymer, or blends of the above polymers. These protective films are usually attached to the polarizing element using an adhesive layer.

Furthermore, more than one kind of any suitable additives may be included in the protective film. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and coloring agents. The content of the above-mentioned thermoplastic resin in the protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When the content of the thermoplastic resin in the protective film is 50% by weight or less, there is a possibility that the high transparency and the like inherent in the thermoplastic resin may not be sufficiently 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 above-mentioned protective film can be determined as appropriate. Generally, it is preferably 5 to 50 μm, and more preferably 5 to 45 μm in terms of workability such as strength and operability, and thinness.

A functional layer such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer, or an anti-glare layer may be provided on the surface of the protective film that does not adhere to the polarizing element. In addition, the functional layers such as the hard coating layer, the anti-reflection layer, the anti-sticking layer, the diffusion layer, or the anti-glare layer may also be provided on the protective film itself, and may also be provided independently of the protective film.

<Interposer>

The protective film and the polarizing element are laminated via an interlayer such as an adhesive layer, an adhesive layer, and an undercoat layer (undercoat layer). At this time, it is more preferable to deposit both without an air gap through the interposer. Moreover, the interposing layer of the polarizing element a1 and the protective film a2 is also not shown in FIG. 2.

The adhesive layer is formed by the adhesive. The type of 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. As the adhesive, various forms such as an aqueous system, a solvent system, a hot melt system, and an active energy ray curing type can be used, and preferably an aqueous adhesive or an active energy ray Hardening adhesive.

Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, and water-based polyesters. Aqueous adhesives are usually used in the form of adhesives containing aqueous solutions, usually containing 0.5 to 60% by weight of solid components. to make.

The active energy ray-curable adhesive is an adhesive that is hardened by active energy rays such as electron beams, ultraviolet rays (radical curing type, cationic curing type), and can be used in the form of electron beam curing type or ultraviolet curing type, for example. For the active energy ray hardening type adhesive, for example, a photo radical hardening type adhesive can be used. When a photoradical hardening type active energy ray hardening type adhesive is used as the ultraviolet curing type, the adhesive contains a radical polymerizable compound and a photopolymerization initiator.

The coating method of the adhesive can be appropriately selected according to the viscosity of the adhesive or the target thickness. Examples of the coating method include, for example, a reverse coater, a gravure coater (direct, reverse, or offset), a rod reverse coater, a roll coater, and a die coater. Bar coater, rod coater, etc. In addition, for coating, a method such as a dipping method may be used as appropriate.

In addition, the application of the above-mentioned adhesive is preferably performed when the thickness of the adhesive layer finally formed becomes 30 to 300 nm when an aqueous adhesive is used. The thickness of the adhesive layer is further preferably 60 to 150 nm. On the other hand, when an active energy ray-curable adhesive is used, it is preferably performed so that the thickness of the adhesive layer becomes 0.2 to 20 μm.

Furthermore, when laminating the polarizing element and the protective film, an easy adhesion layer may be provided between the protective film and the adhesive layer. The easy-adhesion layer can have, for example, a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a polysiloxane system, a polyamine skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, etc. Of various resins. These polymer resins can be used alone, or two Used in combination of more than one species. In addition, other additives may be added during the formation of the easy-adhesion layer. Specifically, stabilizers such as adhesion-imparting agents, ultraviolet absorbers, antioxidants, and heat-resistant stabilizers can also be used.

The adhesive layer is formed by the adhesive. As the adhesive, various adhesives can be used, and examples include rubber adhesives, acrylic adhesives, polysiloxane adhesives, urethane adhesives, vinyl alkyl ether adhesives, and polyadhesives. Vinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, etc. The adhesive base polymer can be selected according to the type of adhesive mentioned above. Among the above-mentioned adhesives, acrylic adhesives can be preferably used in terms of excellent optical transparency, adhesive properties exhibiting suitable wettability and cohesiveness and adhesiveness, and excellent weather resistance or heat resistance.

The undercoat layer (undercoat layer) is formed to improve the adhesion between the polarizing element and the protective film. The material constituting the undercoat layer is not particularly limited as long as it exhibits a certain degree of relatively strong adhesion between both the base film and the polyvinyl alcohol-based resin layer. For example, a thermoplastic resin excellent in transparency, thermal stability, and extensibility can be used. Examples of the thermoplastic resin include acrylic resins, polyolefin resins, polyester resins, polyvinyl alcohol resins, and mixtures thereof.

<other functional film>

As the functional film of the present invention, the same protective film as exemplified in the above-mentioned polarizing film can be used. As the functional film, the film (functional substrate film) may be used alone, or a surface treatment layer may be provided on one side or both sides of the functional substrate film as shown in FIG. 5. Examples of the surface treatment layer include a hard coat layer, an anti-reflection layer, which can be applied to the protective film of the polarizing film, Functional layers such as anti-sticking layer, diffusion layer or anti-glare layer. The thickness of the functional substrate film can be appropriately determined within a range of 110 μm or less. In general, it is preferably 10 to 110 μm, and more preferably 25 to 105 μm in terms of workability such as strength and workability, and thin layer properties. The surface treatment layer is preferably 25 μm or less, and more preferably 15 μm or less.

<Adhesive layer for functional film>

In the formation of the adhesive layer for the functional film, a suitable adhesive can be used, and the type is not particularly limited. Examples of the adhesive include rubber adhesives, acrylic adhesives, polysiloxane adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, and polyadhesives. Vinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, etc.

Among these adhesives, those excellent in optical transparency, exhibiting suitable wettability, cohesiveness, and adhesiveness, and excellent in weather resistance, heat resistance, etc. can be preferably used. As those exhibiting such characteristics, an acrylic adhesive is preferably used.

As a method of forming an adhesive layer for a functional film, for example, it can be produced by applying the above adhesive to a release film (release film, etc.) subjected to a peeling treatment, and drying and removing a polymerization solvent, etc. to form an adhesive After the agent layer, the method is transferred to the polarizing film; or the polarizing film is coated with the above-mentioned adhesive, and the polymerization solvent is dried and removed to form an adhesive layer on the polarizing element. Furthermore, when applying the adhesive, more than one solvent other than the polymerization solvent may be added again.

As the release film subjected to the peeling treatment, a silicone release liner can be preferably used. In the step of coating and drying the adhesive of the present invention on such a liner to form an adhesive layer, as a method of drying the adhesive, an appropriate method can be suitably adopted according to the purpose. It is preferable to use a method in which the above coating film is dried by overheating. The heating and drying temperature is preferably 40°C to 200°C, further preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. By setting the heating temperature to the above range, an adhesive having excellent adhesive properties can be obtained.

The drying time can be suitably selected as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

As a method of forming the adhesive layer, various methods can be used. Specifically, for example, roll coating, contact roll coating, gravure coating, reverse coating, roll brush coating, spray coating, dip roll coating, bar coating, blade coating, air knife Coating, curtain coating, die lip coating, extrusion coating method using die coater, etc.

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

<First release film: used to protect the adhesive layer for functional film>

The first release film is used, for example, to hold the adhesive layer for a functional film until it is put into practical use (see FIGS. 2 and 3 ). As the first release film, the above-mentioned release film (such as a separator) used to form the adhesive layer for a functional film can be used as the first release film directly. The first release film (release film) has a first base film. As a constituent material of the first base film, for example, polyethylene, polypropylene, and polyparaphenylene terephthalate can be cited. Plastic films such as ethylene formate and polyester films, porous materials such as paper, cloth, and non-woven fabrics, nets, foamed sheets, metal foils, and laminates such as these are suitable for thin sheets, etc. In terms of excellent performance, a plastic film can be preferably used.

The plastic film is not particularly limited as long as it can protect the adhesive layer for the functional film, and examples thereof include polyethylene film, polypropylene film, polybutene film, polybutadiene film, and polymethyl Pentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer Membrane etc.

The first base film of the first peeling film may be carried out by using a silicone-based, fluorine-based, long-chain alkyl-based or fatty amide-based mold release agent, silicon dioxide powder, etc. as needed. Demoulding and anti-fouling treatment, or anti-static treatment such as coating type, mixing type and evaporation type. In particular, the peelability of the adhesive layer for functional films can be further improved by appropriately performing peeling treatments such as polysiloxane treatment, long-chain alkyl treatment, and fluorine treatment on the surface of the release film. The thickness of the first base film of the first release film (release film) is designed such that the first bending stiffness of the first release film is greater than the second bending stiffness of the second release film.

<First release film, second release film: when used as a surface protection film>

The first release film and the second release film can be used as a surface protection film, for example. Regarding the surface protection film, when the functional film has an adhesive layer for the functional film on one side, it can be used as the second release film on the other side (see FIGS. 2 and 3 ). In addition, the surface protection film can be used as the first release film and the second release film on both sides of the functional film (see FIGS. 4 and 5 ).

The first and second release films (surface protective films) have first and second base films, respectively. As the first and second substrate films used for the surface protective film, from the viewpoint of inspection properties and management properties, a film material having isotropy or near isotropy is selected. Examples of the film material include polyester resins such as polyethylene terephthalate films, cellulose resins, acetate resins, polyether resins, polycarbonate resins, and polyamides. Transparent polymers such as polyolefin resins such as resins, polyimide resins, polyethylene, polypropylene, and acrylic resins. Among these, polyester resins are preferred. The first and second substrate films can also be used in the form of a laminate of one or more film materials, or an extension of the above 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 designed such that the first bending stiffness of the first release film is greater than the second bending stiffness of the second release film.

As the surface protection film, those using the above-mentioned first and second base film as a self-adhesive film, and additionally having the above-mentioned base film and adhesive layer for surface protection film. Regarding the surface protective film, from the viewpoint of protecting the functional film, it is preferable to use one having an adhesive layer for the surface protective film.

The adhesive layer for the surface protective film used for the lamination of the surface protective film can be suitably selected from, for example, (meth)acrylic polymer, polysiloxane polymer, polyester, polyurethane, polyamide, Polyether, fluorine-based or rubber-based polymers are used as adhesives for basic polymers. From the viewpoints of transparency, weather resistance, heat resistance, and the like, an acrylic adhesive using an acrylic polymer as a base polymer is preferred. The thickness of the adhesive layer for the surface protective film (dry film thickness) can be determined according to the required adhesive force. It is usually about 1 to 100 μm, preferably 5 to 50 μm.

Furthermore, for the surface protection film (in the case where the adhesive layer for the surface protection film is provided) It is the opposite side of this surface), a low-adhesion material such as polysiloxane treatment, long-chain alkyl treatment, fluorine treatment, etc. may be used to provide a peeling treatment layer.

<Peeling of the first peeling film>

The film lamination system of the present invention laminates a functional film and a first release film and a second release film located on both sides thereof, and is prepared in a monolithic state of a specific shape (step (1)). Examples of specific shapes include rectangular objects. Then, the first peeling film is peeled off from the film laminate (step (2)). When peeling the first peeling film, the film laminate can fix the second peeling film side by suction, for example, and peel off the first peeling film using a peeling roller or the like (for example, refer to Japanese Patent Laid-Open No. 9-114384) Bulletin, etc.).

<Manufacture of optical display panel>

When the functional film having the adhesive layer for the functional film is used as the film laminate of the present invention (for example, refer to FIGS. 2 and 3), the first step (1) and the subsequent step (2) are removed. 1. The film laminate of the release film (for example, the functional film with an adhesive layer with a surface protection film as the second release film) is bonded to one surface of the optical unit through step (3). In the step (3), the side of the functional film adhesive layer of the functional film is attached to the optical unit to manufacture an optical display panel.

<other optical layer>

In the case of using an optical film as the functional film of the present invention, the optical film can be laminated and used on 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, one layer or more than two layers of reflective plates, semi-transmissive plates, and retardation plates (including 1/2 or 1/4) Wavelength board), viewing angle compensation film, brightness enhancement film, etc. can be used An optical layer of a liquid crystal display device or the like is formed.

The optical film laminated with the above-mentioned optical layer can also be formed by sequentially layering individually in the manufacturing process of a liquid crystal display device, etc., and the optical film laminated in advance has excellent quality stability and assembly work, and can be The advantages of manufacturing steps of liquid crystal display devices and the like are improved. For the lamination, an appropriate adhesion method such as an adhesive layer can be used. When the polarizing film or other optical film with an adhesive layer mentioned above is attached, these optical axes can be set to an appropriate arrangement angle according to the target phase difference characteristics and the like.

<optical unit> (LCD unit, LCD panel)

The liquid crystal cell has a structure in which a liquid crystal layer is sealed between a pair of substrates (a first substrate (viewable side surface) Pa and a second substrate (rear surface) Pb) that are opposed to each other. Any type of liquid crystal cell can be used. However, in order to achieve high contrast, it is preferable to use a liquid crystal cell in a vertical alignment (VA) mode or an In Plane Switching (IPS) mode. The liquid crystal display panel is attached with a polarizing film on one side or both sides of the liquid crystal cell, and a driving circuit is installed as needed.

A suitable liquid crystal display device can be formed on a liquid crystal display device having an optical film arranged on one or both sides of the liquid crystal cell, or a backlight device or a reflective plate used in an illumination system. In this case, the optical film of the present invention can be disposed on one side or both sides of the liquid crystal cell. In the case where the optical film of the present invention is provided on both sides, these may be the same or different. Furthermore, when forming a liquid crystal display device, for example, one or more layers of diffusion plate, anti-glare layer, anti-reflection film, protective plate, prism array, lens array plate, light diffusion plate, backlight device and other suitable components can be arranged Yu Shi Suitable location.

(Organic EL unit, organic EL display panel)

The organic EL unit as another optical unit is formed by sandwiching an electroluminescent layer between a pair of electrodes. For the organic EL unit, for example, any type such as a top emission method, a bottom emission method, or a double-sided emission method can be used. In the organic EL display panel, the optical film (polarizing film) of the present invention and the retardation film are bonded to the organic EL unit, and a drive circuit is installed as necessary.

[Example]

Hereinafter, the present invention will be described with examples, but the present invention is not limited to the examples shown below. In addition, the parts and% in each case are based on weight. In the following, the room temperature storage conditions without special requirements are 23°C and 65%RH.

<Production of Polarizing Film> (Manufacture of polarizing elements)

Polyethylene terephthalate (IPA (Isophtalic Acid, isophthalic acid) copolymerized with PET (Polyethylene terephthalate, polyterephthalic acid) Ethylene glycol)) film (thickness: 100 μm) on one side of the substrate was corona treated, and the corona treated surface was coated at 25° C. with a ratio of 9:1 containing polyvinyl alcohol (degree of polymerization 4200, saponification) Degree 99.2 mol%) and acetoacetyl modified PVA (polymerization degree 1200, acetoacetyl modification 4.6%, saponification degree 99.0 mol% or more, trade name "GOHSEFIMER" manufactured by Japan Synthetic Chemical Industry Corporation The aqueous solution of Z200") was dried to form a PVA-based resin layer with a thickness of 11 μm to produce a laminate.

The obtained laminate was uniaxially extended in the longitudinal direction (longitudinal direction) of the free end to 2.0 times in the oven at 120°C between the rollers with different peripheral speeds (air assisted extension treatment).

Next, the laminate was immersed in an insoluble bath at a liquid temperature of 30° C. (a boric acid aqueous solution obtained by mixing boric acid with 4 parts by weight for 100 parts by weight of water) for 30 seconds (insoluble treatment).

Then, in a dye bath having a liquid temperature of 30° C., the iodine concentration and the immersion time were adjusted so that the polarizing plate had a specific transmittance, and the immersion was performed. In this example, the iodine aqueous solution obtained by mixing 0.2 parts by weight of iodine and 1.0 parts by weight of potassium iodide with respect to 100 parts by weight of water was immersed for 60 seconds (dyeing treatment).

Then, it was immersed for 30 seconds in a crosslinking bath (a boric acid aqueous solution obtained by mixing potassium iodide for 100 parts by weight of water and 3 parts by weight of boric acid) at a liquid temperature of 30°C (crosslinking treatment).

Thereafter, while immersing the laminate in a boric acid aqueous solution at a liquid temperature of 70° C. (an aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water and 5 parts by weight of potassium iodide), the rollers along the circumferential speed The longitudinal direction (longitudinal direction) is uniaxially stretched (in-water stretch treatment) so that the total stretch magnification becomes 5.5 times.

Thereafter, the laminate was immersed in a washing bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 30° C. (washing treatment).

Thus, an optical film laminate including a polarizing element having a thickness of 5 μm was obtained.

(Protection film)

Protective film 1: A film with a total thickness of 50 μm applied with a low-reflection surface treatment with a thickness of 10 μm on one side of a triacetyl cellulose film with a thickness of 40 μm.

Protective film 2: A triacetyl cellulose film with a thickness of 40 μm is used.

(Applicable to adhesives for protective films 1 and 2)

40 parts by weight of N-hydroxyethylacrylamide (HEAA) and 60 parts by weight of acrylomorpholine (ACMO) and 3 parts by weight of photoinitiator "IRGACURE 819" (manufactured by BASF) were mixed to prepare ultraviolet curing. Type adhesive.

<Production of single-sided protective polarizing film A1>

On the surface of the polarizing element of the optical film laminate, apply the ultraviolet curable adhesive so that the thickness of the adhesive layer after curing becomes 1 μm, and apply the protective film 1 (without low reflection surface treatment) The surface) is irradiated with ultraviolet rays as active energy rays to harden the adhesive. For the ultraviolet irradiation, a metal halogen lamp enclosed with gallium (irradiation device: Fusion UV Systems, Inc. manufactured Light HAMMER10, lamp: V lamp, peak illuminance: 1600mW/cm ² , cumulative exposure 1000/mJ/cm ² (wavelength 380~440nm)), the illuminance of ultraviolet ray is measured using Sola-Check system manufactured by Solatell. Then, the amorphous PET substrate was peeled off, and a single-sided protective polarizing film A using a thin polarizing element was produced. Regarding the optical characteristics of the obtained single-sided protective polarizing film A1, the single transmittance was 42.8% and the degree of polarization was 99.99%. The thickness of the obtained single-sided protective polarizing film was 56 μm.

<Fabrication of polarizing film A2 on both sides> (Manufacture of polarizing element with a thickness of 23 μm)

A polyvinyl alcohol film with 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 it. Then, it was immersed in an aqueous solution with a concentration of 0.3% of iodine/potassium iodide (weight ratio=0.5/8), and the membrane was dyed while extending 3.5 times. Thereafter, in a 65°C borate aqueous solution, the total elongation ratio was extended to 6 times. stretch. After stretching, it was dried in an oven at 40° C. for 3 minutes to obtain a PVA-based polarizing element (thickness 23 μm).

On one side of the polarizing element, after the protective film 1 is bonded via an ultraviolet curing adhesive as described above, the protective film 2 is bonded on the other single surface via an ultraviolet curing adhesive as described above. Regarding the optical characteristics of the obtained two-sided protective polarizing film A2, the transmittance was 42.8% and the degree of polarization was 99.99%. The thickness of the protective polarizing film A2 on both sides is 115 μm.

<Single Transmittance T and Polarization P of Polarizing Element>

The single transmittance T and the degree of polarization P of the obtained polarizing film were measured using a spectroscopic transmittance meter (Dot-3c by Murakami Color Technology Research Institute) with an integrating sphere.

Furthermore, the polarization degree P is the transmission rate (parallel transmission rate: Tp) when two identical polarizing films are overlapped in such a manner that the transmission axes of the two become parallel, and the transmission axes of the two The transmittance (orthogonal transmittance: Tc) in the case of overlapping by the orthogonal method is obtained by substituting the following formula. Polarization P(%)={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100

Each transmittance is expressed as the Y value of the visibility compensation by the 2 degree field of view (C light source) of JIS Z8701 by setting the complete polarization obtained by the Glan-Taylor polarizing element to 100%.

<Preparation of Adhesive>

In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer, and a stirring device, mix 100 parts of butyl acrylate, 3 parts of acrylic acid, 0.1 parts of 2-hydroxyethyl acrylate, and 2,2'-azobisisobutyronitrile 0.3 A portion was added together with ethyl acetate to prepare a solution. Then, stirring was carried out while blowing nitrogen into the solution, and the reaction was carried out at 55° C. for 8 hours to obtain a weight-average molecular weight of A solution of 2.2 million acrylic polymers. Furthermore, ethyl acetate was added to the solution containing the acrylic polymer to obtain an acrylic polymer solution whose solid content concentration was adjusted to 30%.

For 100 parts of the solid content of the acrylic polymer solution, 0.5 parts of a crosslinking agent containing a compound having an isocyanate group as a main component (manufactured by Nippon Polyurethane (shares), trade name "Coronate" is prepared in sequence. L"), and 0.075 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KMB-403") as a silane coupling agent to prepare an adhesive solution.

<Functional film: TAC film>

A3: Prepare triacetyl cellulose film with a thickness of 80 μm.

A4: Prepare triacetyl cellulose film with a thickness of 25 μm.

<Functional film: a film with a low-reflection surface treatment layer on both sides>

A5: Prepare two pieces of the low-reflection surface treatment film (thickness 50 μm) of the above-mentioned protective film 1, and prepare the surface of the film that has not been subjected to the low-reflection surface treatment to pass each other via an ultraviolet curing adhesive (thickness 5 μm) in the same manner as above A film with a low-reflection surface treatment layer (AR film on both sides) provided on both sides. The thickness of the AR (Anti-Reflection) film on both sides is 105 μm.

Example 1 <Lamination of surface protection film>

On the protective film 1 side of the single-sided protective polarizing film A1, a surface protective film (second peeling film, (Trade name RP108C manufactured by Nitto Denko Corporation). As the surface protection film, a polyester resin film (second base film) with a thickness of 25 μm having an adhesive layer (equivalent to an adhesive layer for surface protection film) with a thickness of 15 μm is used.

<Formation of adhesive layer with release film (first release film)>

Apply the above adhesive solution to a polyethylene terephthalate film containing a peeling treatment so that the thickness after drying becomes 20 μm (the thickness of the first base film is 50 μm: DIAFOIL manufactured by Mitsubishi Resin Co., Ltd.) MRF) the surface of the release film (isolation film) and dried to form an adhesive layer (equivalent to an adhesive layer for polarizing film (functional film)). Then, the above-mentioned adhesive layer was attached to the side of the polarizing element of the single-sided protective polarizing film A with a surface protective film to produce the film laminate of the present invention (refer to FIG. 3: attached adhesive with release film and surface protective film) Polarizer film of the agent layer).

Comparative Examples 1, 2, Reference Examples 1~3

In Example 1, the type of polarizing film, the thickness of the second substrate film used as the surface protection film of the second release film, and the thickness of the first substrate film used as the release film of the first release film were changed to As shown in Table 1, except for this, a film laminate was produced in the same manner as in Example 1.

Example 2 <Lamination of surface protection film>

Surface protective films (first and second release films) are provided on both sides of the functional film A3 (80 μm thick TAC film).

For the first release film, use it on a polyester resin film (first substrate film) with a thickness of 100 μm Those having an adhesive layer (equivalent to an adhesive layer for surface protection film) with a thickness of 15 μm (trade name RP108C manufactured by Nitto Denko Corporation) are used as the surface protection film.

For the second release film, a polyester resin film (second substrate film) with a thickness of 25 μm having an adhesive layer (equivalent to an adhesive layer for surface protection film) with a thickness of 15 μm (product manufactured by Nitto Denko Corporation) Name RP108C) as a surface protective film.

Examples 3 to 5, Comparative Examples 3 to 6

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

The film laminates and their constituent materials obtained in the above examples, comparative examples and reference examples were evaluated as follows. The results are shown in Table 1.

<Bending rigidity test>

The bending stiffness of the first and second release films was measured by the following method.

The No.476 cantilever type softness testing machine manufactured by Yasuda Seiki Co., Ltd. was used. In addition, in this test, in order to eliminate the influence of static electricity, the samples used in the test are properly destaticized.

For each film laminate, a rectangular object F (sample) of 20 mm×150 mm was prepared. To accommodate The top surface of the smooth SUS pallet 41 is set in such a way that the top of the SUS pallet 41 is flat (20mm×150mm: the same size as the sample), one end of the long side has a slope of 45°, and the cross section is trapezoidal ( (See Figure 6).

The above sample was smoothly moved to the slope side (1) at a pressing speed of 10 mm/sec. Stop the movement of the sample at the point where the front end of the sample first contacts the slope (2). The distance L (mm) of the sample moving on the top plane is measured.

Regarding the bending stiffness (mm), for each sample, the shortest linear distance L (mm) was measured three times for each of the two patterns with the first surface set to the upper side and the second surface set to the upper side. Samples), and calculate the arithmetic mean of these.

<Measurement of peel force>

The film laminate obtained in Examples, Comparative Examples, and Reference Examples was cut to 25 mm × 100 mm, and the first peeling film and the second peeling film on the side where the peeling force was not measured were peeled off, and then double-sided tape was used ( Manufactured by Nitto Denko Corporation, double-sided tape No. 511) is attached to non-alkali glass with a thickness of 0.5mm. Attach the transparent tape to the short-side end of the polarizing film with an adhesive layer attached to the alkali-free glass. After peeling off only the starting part in advance, use a tension machine to remove the first peeling film or the second peeling film by 180 ° Peeling, the speed of 0.3m/min is parallel to the longitudinal direction of the film. The peeling force of the first peeling film and the second peeling film were measured separately. The results are shown in Table 1.

<Pickup Test>

The film laminates obtained in Examples, Comparative Examples, and Reference Examples were cut to 150 mm×150 mm to make a single piece (sample).

Let the first release film side of the above sample be the upper side and the second release film side the lower side. Using the double-sided tape (made by Nitto Denko Corporation, double-sided tape No. 511), the second release film side (all) of the above sample was fixed to the glass. On the other hand, a pickup roller that winds a double-sided tape with a width of 5 mm (manufactured by Nitto Denko Corporation, double-sided tape No. 511) onto a roller with a diameter of 45 mm is prepared. Next, using a pick-up roller, the above-mentioned roller with a diameter of 45 mm was moved parallel to the diagonal direction of the sample from the edge end of the sample fixed on the glass. The above operation was performed 10 times, and the number of times peeling from the first peeling film was shown in Table 1 as "number of times/10".

<Floating test>

The film laminates obtained in Examples, Comparative Examples and Reference Examples were cut to 25 mm×100 mm to make a single piece (sample).

Set the first release film side of the above sample as the upper side and the second release film side as the upper side, and use a double-sided tape (double-sided tape No. 511 manufactured by Nitto Denko Corporation) to set the second release film side of the above sample (Only 20~100mm from the end of the long side direction) Attach to the glass and fix it to the glass. That is, the portion of 0 to 20 mm from the end in the longitudinal direction of the above-mentioned sample becomes in a suspended state.

Then, at the end of the sample fixed on the glass (the side in the suspended state), after attaching a transparent tape with a width of 25 mm to the test piece, the sample was pulled at an angle of 30° along the long side of the sample at 300 mm/min Stretching speed stretches the above transparent tape.

After performing the above operation, if the first peeling film is not peeled off, it is indicated as "pass" in Table 1. When peeling of the first peeling film occurs, the distance (mm) of stretching is described in Table 1.

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

1‧‧‧The first release film

2‧‧‧Second peeling film

A‧‧‧Functional film

F‧‧‧Single film optical film

Claims (18)

A film laminate, characterized in that it is a monolithic layer formed by sequentially stacking a first release film having a first base film, a functional film, and a second release film having a second base film, and the above The first peeling film is peeled earlier than the second peeling film, the thickness of the functional film is 110 μm or less, and the first bending stiffness (mm) of the first peeling film in the bending rigidity test is greater than that of the second peeling film in bending The second bending stiffness (mm) in the rigidity test. The film laminate according to claim 1, wherein the difference between the first bending stiffness (mm) and the second bending stiffness (mm) is 10 mm or more. The film laminate according to claim 1, wherein the peeling force (1) of the first peeling film is equal to or greater than the peeling force (2) of the second peeling film. The film laminate according to claim 1, wherein the thickness of the first base film is greater than the thickness of the second base film. The film laminate according to claim 1, wherein the thickness of the first base film is 40 μm or more. The film laminate according to claim 1, wherein the thickness of the second base film is 35 μm or less. The film laminate as claimed in claim 1, 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 polarizing element having a thickness of 10 μm or less. The film laminate according to claim 8, wherein the polarizing film is a single-sided protective polarizing film having a protective film on only one side of the polarizing element. The film laminate according to claim 7, wherein the optical film has a surface treatment layer on one side or both sides. The film laminate according to claim 1, wherein the first release film and the second release film are both surface protective films. The film laminate according to any one of claims 1 to 12, wherein the functional film has an adhesive layer for a functional film on the side where the first release film is provided, and the second release film is a surface protective film. The film laminate according to claim 12, wherein the surface protective film has an adhesive layer for a surface protective film, and is laminated on the functional film through the adhesive layer. The film laminate as claimed in claim 12, wherein the surface protection film is a self-adhesive film. A peeling method for a first peeling film, which peels the first peeling film from the film laminate according to any one of claims 1 to 15. A method for manufacturing an optical display panel, comprising: a step (1) of preparing a film laminate according to any one of claims 13 to 15; a step (2) of peeling a first peeling film from the film laminate; and The step (3) of bonding the side of the adhesive layer for a functional film of the film laminate from which the first release film has been peeled off to one surface of the optical unit. The method for manufacturing an optical display panel according to claim 17, wherein the optical unit is a liquid crystal unit or an organic EL unit.

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