WO2021100490A1 - Adhesive-equipped optical film and method for producing same - Google Patents

Abstract

Provided is an adhesive-equipped optical film, the adhesive of which is unlikely to protrude from the end surface thereof. An adhesive-equipped optical film (101) equipped with an adhesive layer (21) secured to one principal surface of the optical film (10), wherein a release film (41) is temporarily adhered to the adhesive layer. The thickness of the adhesive layer is at least 50μm. The release film covers the end surface of the adhesive layer in a range spanning at least 10% of the adhesive layer in the thickness direction thereof. The adhesive-equipped optical film may be provided with a separate adhesive layer on another surface of the optical film.

Description

Optical film with adhesive and its manufacturing method

The present invention relates to an optical film with an adhesive having an adhesive layer on the main surface of the optical film and a release film temporarily adhered on the adhesive layer.

In display devices such as liquid crystal displays and organic EL displays and input devices for displays such as touch panels, a sheet-like transparent adhesive is used for bonding optical members. Further, a cover window made of a transparent resin plate, a glass plate, or the like may be attached to the visible surface of the image display device via a transparent adhesive.

A colored layer is printed on the frame portion of the cover window for the purpose of decoration and light shielding, and a printing step of about 10 μm to several tens of μm is generated on the printed portion of the colored layer. For bonding optical members having such a printing step, a thick and soft adhesive sheet is used in order to prevent air bubbles from being mixed into the printing step portion and stress concentration.

The transparent adhesive sheet is generally provided as an adhesive sheet with a release film having a release film temporarily attached to both sides (for example, Patent Document 1). When using the pressure-sensitive adhesive sheet, first, one release film (light release film) is peeled off to expose one surface of the pressure-sensitive adhesive layer and bonded to the first adherend, and then the other release film is used. The film (heavy release film) is peeled off and the second adherend is attached to the other surface of the pressure-sensitive adhesive layer. Patent Document 2 discloses an optical film with an adhesive in which an adhesive layer is previously laminated on an optical film such as a polarizing plate.

International Publication No. 2013/161666 Japanese Unexamined Patent Publication No. 2014-115468

When a thick and soft adhesive is used, the adhesive exposed on the end face of the adhesive sheet cut out into a sheet of a predetermined size easily protrudes from the end face, causing foreign matter to adhere to the end face and contamination of the surroundings. There is. Further, when a plurality of adhesive sheets are stacked and stored, the adhesive sheets tend to block each other due to the adhesive squeezing out from the end face, and it may be difficult to pick up the adhesive sheets one by one.

In order to suppress defects due to the adhesive squeezing out from the end face, in Patent Document 2, cutting or processing is performed so that the end face of the pressure-sensitive adhesive layer is inside the end face (cut surface) of the release film. Has been proposed. However, since the soft adhesive easily flows, even if the end face of the pressure-sensitive adhesive layer exists inside the end face of the film, the pressure-sensitive adhesive layer is deformed by external stress during storage or transportation, and the pressure-sensitive adhesive layer adheres from the end face. The agent may squeeze out and cause contamination or blocking.

In view of the above, an object of the present invention is to provide an optical film with an adhesive that does not easily cause the adhesive to squeeze out from the end face.

The optical film with an adhesive is a first release film that covers the first adhesive layer fixedly laminated on the first main surface of the optical film and the first adhesive layer and is temporarily attached to the first adhesive layer. including. The thickness of the first pressure-sensitive adhesive layer is 50 μm or more. The storage elastic modulus of the first pressure-sensitive adhesive layer at 25 ° C. may be 0.35 MPa or less. The thickness of the first release film may be 45 μm or more.

In at least a part of the region in the thickness direction of the first pressure-sensitive adhesive layer, the end portion of the first release film covers the end face of the first pressure-sensitive adhesive layer. The region where the end portion of the first release film covers the end surface of the first pressure-sensitive adhesive layer is preferably 10% or more of the thickness of the first pressure-sensitive adhesive layer. The distance between the end of the first release film and the end face of the first pressure-sensitive adhesive layer is preferably 2 mm or less. The end portion of the first release film covering the end portion of the first pressure-sensitive adhesive layer may be thinner than the first release film temporarily adhered on the first pressure-sensitive adhesive layer.

The end face of the optical film may be located inside the end of the release film. The end face of the first pressure-sensitive adhesive layer may be located inside the end face of the optical film.

The optical film with an adhesive may include a second adhesive layer fixed and laminated on the second main surface of the optical film. A second release film may be temporarily attached on the second pressure-sensitive adhesive layer.

The adhesive-attached optical film in which the end of the release film covers the end face of the adhesive layer can be obtained, for example, by cutting the end face of the adhesive-attached optical film cut out into a single sheet by an end mill. A plurality of optical films with an adhesive cut out on a single sheet may be stacked to form a machining work, and the machining work may be cut by an end mill.

When the first release film is located above the first pressure-sensitive adhesive layer, it is preferable to carry out end milling by down-cutting. When the first release film is located below the first pressure-sensitive adhesive layer, it is preferable to carry out end milling by up-cutting. From the viewpoint of reducing the adhesion of cutting pieces, it is preferable to carry out end milling by up-cutting.

In the optical film with an adhesive of the present invention, since at least a part of the end face of the adhesive layer is covered with a release film, it is difficult for the adhesive to squeeze out from the end face, and contamination due to the squeeze out of the adhesive can occur. Blocking can be suppressed.

It is sectional drawing of the optical film with adhesive of one Embodiment. It is sectional drawing of the optical film with adhesive of one Embodiment. It is a perspective view of a straight end mill. It is a conceptual diagram for demonstrating the relationship between the moving direction of an end mill and a processing method. It is an optical micrograph of the cross section of the optical film with adhesive of an Example.

[Laminated structure]
FIG. 1 is a cross-sectional view of the optical film 101 with an adhesive according to the embodiment. The optical film 101 with an adhesive has a first adhesive layer 21 on one surface (first main surface) of the optical film 10, and the first release film 41 is detachably attached onto the adhesive layer 21. Has been done.

<Optical film>
The optical film 10 is used for forming an image display device, and is, for example, a polarizing plate. As the polarizing plate, one in which an appropriate transparent protective film is bonded to one side or both sides of the polarizing element, if necessary, is generally used. The polarizer is not particularly limited, and various polarizers can be used. Examples of the polarizer include a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene-vinyl acetate copolymerization system partially saponified film, and two colors such as iodine and a bicolor dye. Examples thereof include a uniaxially stretched film by adsorbing a sex substance, a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrogenated product of polyvinyl chloride.

The transparent protective film as a protective film for the polarizer includes transparency, mechanical strength, thermal stability, moisture blocking, etc. of cellulose-based resin, cyclic polyolefin-based resin, acrylic-based resin, phenylmaleimide-based resin, polycarbonate-based resin, etc. Those having excellent properties and optical isotropic properties are preferably used. When transparent protective films are provided on both sides of the polarizer, protective films made of the same polymer material may be used on the front and back sides thereof, or protective films made of different polymer materials may be used. Further, an optically anisotropic film such as a retardation plate (stretched film) can be used as a protective film for the polarizer for the purpose of optical compensation of the liquid crystal cell, expansion of the viewing angle, and the like.

The optical film 10 may be composed of only a polarizing plate, and even if another film is laminated on one or both surfaces of the polarizing plate via an appropriate adhesive layer or an adhesive layer, if necessary. Good. As such a film, those used for forming an image display device such as a retardation plate, a viewing angle expanding film, a viewing angle limiting (peeping prevention) film, and a brightness improving film are used, and the type thereof is not particularly limited. .. For example, in a liquid crystal display device, an image display cell (liquid crystal cell) and a polarizing plate are used for the purpose of appropriately converting the polarization state of light emitted from the liquid crystal cell to the visual recognition side to improve viewing angle characteristics. An optical compensation film may be used in between. In an organic EL display device, a 1/4 wave plate may be arranged between a cell and a polarizing plate in order to prevent external light from being reflected by a metal electrode layer and visually recognized as a mirror surface. .. Further, by arranging a 1/4 wave plate on the viewing side of the polarizing plate and converting the emitted light into circularly polarized light, it is possible for a viewer wearing polarized sunglasses to visually recognize an appropriate image display. ..

The surface of the optical film 10 may be subjected to a hard coat layer, antireflection treatment, anti-sticking treatment, and treatment for the purpose of diffusion or anti-glare. Further, the surface of the optical film 10 may be subjected to a surface modification treatment for the purpose of improving adhesiveness or the like before attaching the pressure-sensitive adhesive layers 21 and 22. Specific treatments include corona treatment, plasma treatment, frame treatment, ozone treatment, primer treatment, glow treatment, saponification treatment, treatment with a coupling agent, and the like. In addition, an antistatic layer can be appropriately formed.

<First adhesive layer>
The first pressure-sensitive adhesive layer 21 provided on the first main surface of the optical film 10 is formed with a layered pressure-sensitive adhesive. When the pressure-sensitive adhesive sheet is used for forming an image display device, it is preferable that the pressure-sensitive adhesive layer 21 is transparent and absorbs little visible light. The total light transmittance of the pressure-sensitive adhesive layer 21 is preferably 85% or more, more preferably 90% or more. The haze of the pressure-sensitive adhesive layer 21 is preferably 2% or less, more preferably 1% or less. Total light transmittance and haze are measured according to JIS K7136 using a haze meter.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 21 includes acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate / vinyl chloride copolymer, modified polyolefin, epoxy-based, fluorine-based, natural rubber, and synthetic rubber. A rubber-based polymer or the like as a base polymer can be appropriately selected and used.

Since it has excellent optical transparency, exhibits adhesive properties such as appropriate wettability, cohesiveness, and adhesiveness, and is also excellent in weather resistance and heat resistance, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 21 is an acrylic type. An acrylic pressure-sensitive adhesive using a polymer as a base polymer is preferably used. In the acrylic pressure-sensitive adhesive, the content of the acrylic-based base polymer with respect to the total solid content of the pressure-sensitive adhesive composition is preferably 50% by weight or more, more preferably 70% by weight or more, and more preferably 80% by weight or more. Is even more preferable.

As the acrylic base polymer, a polymer having a monomer unit of (meth) acrylic acid alkyl ester as a main skeleton is preferably used. In addition, in this specification, "(meth) acrylic" means acrylic and / or methacryl.

As the (meth) acrylic acid alkyl ester, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferably used. The (meth) acrylic acid alkyl ester may have a branched alkyl group. The content of the (meth) acrylic acid alkyl ester is preferably 40% by weight or more, more preferably 50% by weight or more, still more preferably 60% by weight or more, based on the total amount of the monomer components constituting the base polymer. The acrylic base polymer may be a copolymer of a plurality of (meth) acrylic acid alkyl esters. The arrangement of the constituent monomer units may be random or block.

The acrylic base polymer may contain an acrylic monomer unit having a crosslinkable functional group as a copolymerization component. When the base polymer has a crosslinkable functional group, the gel fraction of the pressure-sensitive adhesive can be easily increased by thermal cross-linking or photocuring of the base polymer. Examples of the acrylic monomer having a crosslinkable functional group include a hydroxy group-containing monomer and a carboxy group-containing monomer. Above all, it is preferable to contain a hydroxy group-containing monomer as a copolymerization component of the base polymer. When the base polymer has a hydroxy group-containing monomer as a monomer unit, the crosslinkability by an isocyanate cross-linking agent or the like is enhanced, and the white turbidity of the adhesive in a high-temperature and high-humidity environment tends to be suppressed, resulting in high transparency. Adhesive is obtained.

Hydroxy group-containing monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and (meth). Examples thereof include 8-hydroxyoctyl acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethyl) cyclohexylmethyl (meth) acrylate.

The content of the hydroxy group-containing monomer is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, still more preferably 3 to 30% by weight, based on the total amount of the monomer components constituting the base polymer.

The acrylic base polymer preferably contains a highly polar monomer unit such as a nitrogen-containing monomer in addition to the hydroxy group-containing monomer unit. By containing a highly polar monomer such as a nitrogen-containing monomer in addition to the hydroxy group-containing monomer, the pressure-sensitive adhesive has high adhesiveness and holding power, and white turbidity in a high-temperature and high-humidity environment is suppressed.

Examples of nitrogen-containing monomers include N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholin, (meth) acryloylmorpholin, and N-vinyl. Examples thereof include vinyl-based monomers such as carboxylic acid amides and N-vinylcaprolactam, acrylonitrile, and methacrylonitrile. Of these, N-vinylpyrrolidone and (meth) acryloylmorpholine are preferably used.

The content of the nitrogen-containing monomer is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, still more preferably 3 to 30% by weight, based on the total amount of the monomer components constituting the base polymer.

The monomer component forming the acrylic polymer may contain a polyfunctional monomer component. A polyfunctional monomer is a monomer having at least two polymerizable functional groups having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group. The polyfunctional monomer may have 3 or more polymerizable functional groups in one molecule.

The acrylic base polymer can be prepared by a known polymerization method such as solution polymerization, UV polymerization, bulk polymerization, and emulsion polymerization. When preparing the base polymer, a polymerization initiator such as a photopolymerization initiator or a thermal polymerization initiator may be used depending on the type of polymerization reaction. Chain transfer agents may be used to adjust the molecular weight of the base polymer.

When a polyfunctional monomer is used in addition to the monofunctional monomer as the monomer component for forming the base polymer, the monofunctional monomer is first polymerized to form a prepolymer composition having a low degree of polymerization (prepolymerization), and the prepolymer is formed. A polyfunctional monomer may be added to the syrup of the composition to polymerize (post-polymerize) the prepolymer and the polyfunctional monomer. By prepolymerizing the prepolymer in this way, the branching points due to the polyfunctional monomer component can be uniformly introduced into the base polymer. Further, a mixture of the prepolymer composition and the unpolymerized monomer component (adhesive composition) may be applied onto the base material and then post-polymerized on the base material to form a pressure-sensitive adhesive layer. Since the prepolymer composition has a low viscosity and is excellent in coatability, according to a method in which a pressure-sensitive adhesive composition, which is a mixture of a prepolymer composition and an unpolymerized monomer, is applied and then post-polymerized on a substrate, a pressure-sensitive adhesive layer is used. The productivity of the pressure-sensitive adhesive layer can be increased, and the thickness of the pressure-sensitive adhesive layer can be made uniform.

The prepolymer composition is obtained by, for example, partially polymerizing (prepolymerizing) a composition (referred to as a "prepolymer forming composition") in which a monomer component constituting an acrylic base polymer and a polymerization initiator are mixed. Can be prepared. The monomer in the composition for forming a prepolymer is preferably a monofunctional monomer such as a (meth) acrylic acid alkyl ester or a polar group-containing monomer among the monomer components constituting the acrylic polymer. The composition for forming a prepolymer may contain a polyfunctional monomer. For example, a part of the polyfunctional monomer component which is a raw material of the base polymer may be contained in the composition for forming the prepolymer, and the rest of the polyfunctional monomer component may be added after the prepolymer is polymerized to be subjected to post-polymerization.

The composition for forming a prepolymer may contain a chain transfer agent or the like, if necessary, in addition to the monomer and the polymerization initiator. The method for polymerizing the prepolymer is not particularly limited, but from the viewpoint of adjusting the reaction time to set the molecular weight (polymerization rate) of the prepolymer in a desired range, polymerization by irradiation with active light such as UV light is preferable. The polymerization initiator and chain transfer agent used for the prepolymerization are not particularly limited, and for example, the above-mentioned photopolymerization initiator and chain transfer agent can be used.

The polymerization rate of the prepolymer is not particularly limited, but is preferably 3 to 50% by weight, more preferably 5 to 40% by weight, from the viewpoint of obtaining a viscosity suitable for coating on a substrate. The polymerization rate of the prepolymer can be adjusted to a desired range by adjusting the type and amount of the photopolymerization initiator, the irradiation intensity and irradiation time of active light such as UV light, and the like.

The prepolymer composition is mixed with the rest of the monomer components constituting the acrylic base polymer (post-polymerization monomer), and if necessary, a polymerization initiator, a chain transfer agent, a silane coupling agent, a cross-linking agent, and the like. , Form the pressure-sensitive adhesive composition. The post-polymerization monomer preferably contains a polyfunctional monomer. As the post-polymerization monomer, a monofunctional monomer may be added in addition to the polyfunctional monomer.

The base polymer may have a crosslinked structure if necessary. The crosslinked structure is formed, for example, by adding a crosslinking agent after the prepolymerization or the polymerization of the base polymer. As the cross-linking agent, commonly used cross-linking agents such as isocyanate-based cross-linking agents, epoxy-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, carbodiimide-based cross-linking agents, and metal chelate-based cross-linking agents can be used. The content of the cross-linking agent is usually in the range of 0 to 5 parts by weight, preferably 0 to 3 parts by weight, based on 100 parts by weight of the acrylic base polymer.

When a cross-linking agent is contained in the pressure-sensitive adhesive composition, it is preferable that a cross-linking treatment by heating is performed before bonding to the adherend to form a cross-linked structure. The heating temperature and heating time in the cross-linking treatment are appropriately set according to the type of the cross-linking agent used, but usually, the cross-linking is performed by heating in the range of 20 ° C. to 160 ° C. for about 1 minute to 7 days.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 21 may be a photocurable pressure-sensitive adhesive that can be cured by light irradiation after being bonded to the adherend. For example, if a photocurable adhesive is used for bonding adherends (for example, cover windows) having a printing step due to decorative printing or the like, the step is followed by bonding with the adhesive before photocuring in a soft state. It is possible to impart properties, and the adhesive reliability can be improved by irradiating ultraviolet rays or the like after bonding to photo-curing the adhesive.

The photocurable pressure-sensitive adhesive preferably contains, for example, a photocurable compound (monomer or oligomer having a photopolymerizable functional group) and a photopolymerization initiator in addition to the polymer. The photocurable pressure-sensitive adhesive preferably contains, as a photopolymerizable compound, a polyfunctional compound having two or more polymerizable functional groups in one molecule. The amount of the polyfunctional compound used varies depending on its molecular weight, the number of functional groups, and the like, but is preferably 10% by weight or less, more preferably 5% by weight or less, based on the total amount of the monomer components constituting the base polymer.

The mixture (adhesive composition) of the above prepolymer composition and the unpolymerized monomer component may be used as it is as a photocurable pressure-sensitive adhesive. Further, after the pressure-sensitive adhesive composition is applied onto the base material, the polymerization rate at the time of post-polymerization is adjusted, and a part of the monomer remains in an uncured state to form a photocurable pressure-sensitive adhesive layer. You may.

In addition to the above-exemplified components, the pressure-sensitive adhesives include silane coupling agents, tackifiers, plasticizers, softeners, deterioration inhibitors, fillers, colorants, antioxidants, surfactants, antistatic agents and the like. It may contain an additive. An ultraviolet absorber may be used in order to impart ultraviolet absorption to the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive composition preferably has a viscosity suitable for coating on a substrate (for example, about 5 to 100 poisons). When the pressure-sensitive adhesive composition is a solution, the viscosity of the solution can be adjusted within an appropriate range by adjusting the molecular weight of the polymer, the solid content concentration of the solution, and the like. When the pressure-sensitive adhesive composition is photocurable, the viscosity can be adjusted within an appropriate range by adding a polyfunctional monomer or the like, the polymerization rate of the prepolymer, or the like. A thickening additive or the like may be used for adjusting the viscosity.

The pressure-sensitive adhesive composition is applied in layers on the base material, and the pressure-sensitive adhesive layer is formed by drying the solvent and cross-linking / curing the base polymer as necessary. When the pressure-sensitive adhesive composition is photocurable, the pressure-sensitive adhesive composition may be applied onto a supporting substrate and then photo-cured by irradiating with ultraviolet rays and / or visible light having a short wavelength. When photocuring, it is preferable to attach a cover sheet to the surface of the coating layer and irradiate light with the pressure-sensitive adhesive composition sandwiched between the two sheets to prevent polymerization inhibition by oxygen. ..

The thickness of the first pressure-sensitive adhesive layer 21 is not particularly limited, but is preferably 50 μm or more from the viewpoint of providing step followability to the printing step of the cover window. _{The thickness D 2} of the first pressure-sensitive adhesive layer may be 80 μm or more, 100 μm or more, or 120 μm or more. The thickness of the first pressure-sensitive adhesive layer 21 is preferably 1000 μm or less, preferably 500 μm or less, 300 μm or less, or 250 μm or less, considering the viewpoint of weight reduction and thinning of the display device, ease of forming the pressure-sensitive adhesive layer, handleability, and the like. It may be.

The storage elastic modulus G'of the first pressure-sensitive adhesive layer 21 at 25 ° C. is preferably 0.35 MPa or less, more preferably 0.30 MPa or less, and even more preferably 0.20 MPa or less. On the other hand, when the first pressure-sensitive adhesive layer 21 is excessively soft, the pressure-sensitive adhesive may be transferred to a cutting blade or the like at the time of cutting when cutting the optical film with a pressure-sensitive adhesive into a single sheet, or the optical film with a single-leaf adhesive may be transferred. The adhesive tends to squeeze out from the end face of the Therefore, the storage elastic modulus G'of the first pressure-sensitive adhesive layer 21 at 25 ° C. is preferably 0.01 MPa or more, more preferably 0.02 MPa or more. The storage elastic modulus G'of the first pressure-sensitive adhesive layer 21 at 25 ° C. may be 0.03 MPa or more, 0.05 MPa or more, or 0.1 MPa or more.

<First release film>
As the release film 41 temporarily adhered on the pressure-sensitive adhesive layer 21, a film having a release layer on the surface of the film base material is preferably used. Examples of the material of the release layer include a silicone-based release agent, a fluorine-based release agent, a long-chain alkyl-based release agent, a fatty acid amide-based release agent, and the like. A silicone release agent is preferable because it can achieve both adhesion to an acrylic pressure-sensitive adhesive and peelability.

As the film base material of the release film, a transparent resin film is preferable. Examples of the resin material include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and (meth) acrylic resins. Examples thereof include polyvinyl chloride-based resins, polyvinylidene chloride-based resins, polystyrene-based resins, polyvinyl alcohol-based resins, polyarylate-based resins, and polyphenylene sulfide-based resins. Among these, polyester resins such as polyethylene terephthalate (PET) are particularly preferable.

The thickness D ₄ of the release film 41 is preferably 10 to 200 μm, more preferably 25 to 150 μm. From the viewpoint of preventing the deformation of the pressure-sensitive adhesive layer according to stored or transported at the external force, it is preferable that the thickness of the release film 41 which is temporarily attached to the thickness D ₂ is greater adhesive layer 21 is 45μm or more. Further, as will be described later, as the thickness of the release film 41 increases, the length L of the end portion 4 of the release film 41 covering the end surface 21e of the adhesive layer 21 tends to increase when the end face is processed. There is. The thickness D ₂ of the release film 41 may be 50 μm or more, 60 μm or more, or 70 μm or more.

<Second adhesive layer>
Like the optical film 102 with an adhesive shown in FIG. 2, the second adhesive layer 22 may be provided on the other surface (second main surface) of the optical film 10. It is preferable that the second release film 42 is attached on the second pressure-sensitive adhesive layer 22.

It is preferable that the pressure-sensitive adhesive layer 22 is transparent and absorbs little visible light. The total light transmittance of the pressure-sensitive adhesive layer 22 is preferably 85% or more, more preferably 90% or more. The haze of the pressure-sensitive adhesive layer 22 is preferably 2% or less, more preferably 1% or less.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 22 is not particularly limited, and those using various polymers as base polymers can be appropriately selected and used. As the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 22, an acrylic pressure-sensitive adhesive using an acrylic polymer as a base polymer is preferable.

The thickness of the second adhesive layer 22 is not particularly limited. Since the second pressure-sensitive adhesive layer 22 is not required to have a step-following property, the thickness of the second pressure-sensitive adhesive layer 22 may be smaller than the thickness of the first pressure-sensitive adhesive layer 21. The thickness of the second pressure-sensitive adhesive layer 22 is preferably 3 to 30 μm, more preferably 5 to 27 μm, and even more preferably 10 to 25 μm. The storage elastic modulus G'of the second pressure-sensitive adhesive layer 22 at 25 ° C. is, for example, about 0.02 to 5 MPa.

<Second release film>
It is preferable that the release film 42 is temporarily attached on the pressure-sensitive adhesive layer 22. As the release film 42, a film having a release layer on the surface of the film base material is preferably used as in the case of the release film 42 on the pressure-sensitive adhesive layer 21. The thickness of the release film 42 may be the same as or different from the thickness of the release film 41. When using an optical film with a double-sided adhesive having adhesive layers 21 and 22 provided on both sides of the optical film 10, when the second adhesive layer 22 is first attached to the adherend, the release film 42 is used. It is preferable that the thickness of the second release film 42 is smaller than the thickness of the first release film 41 because it is easily peeled off selectively. The thickness of the release film 42 is preferably 55 μm or less, and may be 50 μm or less, 45 μm or less, or 40 μm or less.

[Manufacturing of optical film with adhesive]
<Laminating and cutting out single-wafer sheets>
An optical film with an adhesive is formed by laminating the first pressure-sensitive adhesive layer 21 and the first release film 41 on the first main surface of the optical film 10. Further, by laminating the second pressure-sensitive adhesive layer 22 and the second release film 42 on the second main surface of the optical film 10, an optical film with a double-sided pressure-sensitive adhesive is formed.

As a method of providing the first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 22 on the optical film 10, for example, after forming the pressure-sensitive adhesive layer on the release film, the pressure-sensitive adhesive layer is transferred onto the optical film 10. Method: A method in which the pressure-sensitive adhesive composition is applied to the optical film 10 and the solvent is removed or cured on the optical film 10 can be mentioned. In the method of transferring the pressure-sensitive adhesive layer onto the optical film, the release film used for forming the pressure-sensitive adhesive layer may be used as it is as the release films 41 and 42.

It is preferable that the pressure-sensitive adhesive layers 21 and 22 and the release films 41 and 42 are attached by a roll-to-roll method. A single-wafer optical film with an adhesive can be obtained by producing a large-area optical film with an adhesive (mother substrate) by a roll-to-roll method and then cutting it into a predetermined size according to the size of the adherend. In this method, a large number of sheet products can be obtained from the mother substrate, so that productivity can be improved.

The shape and size of the single-wafer adhesive-attached optical film are set according to the shape and size of the adherend. For example, when the optical film is placed in front of the image display device, the size of the adhesive optical film is approximately equal to the size of the screen.

Examples of the method of cutting out the optical film with an adhesive to a predetermined size include a method of punching with a Thomson blade or the like, a method of cutting with a cutting machine such as a super cutter, a method of using a cutter such as a round blade or a countersunk blade, and laser processing. ..

In the single-wafer product cut by these methods, the position of the end face of the pressure-sensitive adhesive layer 21 and the position of the end face of the release film 41 are aligned, and the end face of the pressure-sensitive adhesive layer 21 is exposed to the outside. Since the pressure-sensitive adhesive layer 21 has a large thickness and easily flows, the pressure-sensitive adhesive may protrude from the end face during storage or transportation, which may cause contamination or blocking.

<Shape of the edge of the sheet>
In the optical film with an adhesive of the present invention, as schematically shown in FIGS. 1 and 2, the end 4 of the release film 41 temporarily attached to the adhesive layer 21 is outside the adhesive layer 21. Overhanging. In at least a part of the area in the thickness direction of the pressure-sensitive adhesive layer 21, the end portion 4 of the release film 41 covers the end surface 21e of the pressure-sensitive adhesive layer 21. The length L in the thickness direction of the region where the end portion 4 of the release film 41 covers the end surface of the first pressure-sensitive adhesive layer 21 is preferably 10% or more _{of the thickness D 2 of the first pressure-sensitive adhesive layer 21.}

In the optical film with an adhesive, the optical film 10 and the adhesive layer 21 are fixedly laminated, whereas the release film 41 is temporarily attached to the adhesive layer 21. Therefore, when the pressure-sensitive adhesive layer is deformed due to the flow of the pressure-sensitive adhesive over time during storage or an external force due to vibration during transportation, the release film 41 and the pressure-sensitive adhesive layer 21 slip at the bonding interface. The misalignment of 41 is likely to occur, and the misalignment of the release film 41 causes the adhesive to squeeze out.

In the optical film with an adhesive of the present invention, since the release film 41 is provided so as to cover the end surface 21e of the adhesive layer 21, deformation of the adhesive layer 21 in the vicinity of the interface with the release film 41 is suppressed. Will be done. Further, since the end portion 4 of the release film 41 is present so as to cover the outer periphery of the pressure-sensitive adhesive layer 21, even if the pressure-sensitive adhesive layer 21 is deformed, the release film 41 is deformed by the pressure-sensitive adhesive layer 21. Since it follows, the displacement of the release film is suppressed.

In the thickness direction of the pressure-sensitive adhesive layer 21, the more the area covered by the edge of the release film 41, the more the deformation of the pressure-sensitive adhesive layer 21 and the position of the release film 41 near the interface with the release film 41. The deviation tends to be suppressed. Therefore, the length L in the thickness direction of the region where the end portion 4 of the release film 41 covers the end surface of the first pressure-sensitive adhesive layer 21 is more preferably 20% or more _{of the thickness D 2 of the first pressure-sensitive adhesive layer 21.} , 30% or more, more preferably 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more. The end portion 4 of the release film 41 may cover the entire end surface of the first pressure-sensitive adhesive layer 21. The length L is preferably 10 μm or more, more preferably 30 μm or more, still more preferably 40 μm or more. L may be 50 μm or more, 80 μm or more, or 100 μm or more.

The end portion 4 of the release film 41 does not necessarily have to be in contact with the end surface 21e of the pressure-sensitive adhesive layer 21. On the other hand, when the end portion of the release film and the end surface 21e of the pressure-sensitive adhesive layer are excessively separated, the action of suppressing the flow of the pressure-sensitive adhesive near the interface with the release film 41 and the displacement of the release film 41. May not be fully exhibited. _{Therefore, the distance Y 4} (maximum distance in the direction orthogonal to the thickness direction) between the end portion 4 of the release film 41 and the end surface 21e of the pressure-sensitive adhesive layer 21 is preferably 2 mm or less, more preferably 1 mm or less, and 500 μm or less. Is more preferable, and it may be 300 μm or less, 200 μm or less, or 100 μm or less.

The thickness of the release film (edge 4 of the release film) covering the end surface of the pressure-sensitive adhesive layer 21 is smaller than the thickness of the release film 41 temporarily adhered on the main surface of the pressure-sensitive adhesive layer 21. May be good. The thickness of the end portion 4 of the release film may be 90% or less, 70% or less, or 50% or less of the thickness of the release film 41. As shown in FIGS. 1 and 2, the end portion 4 of the release film may have a tapered shape whose thickness is smaller toward the tip end.

The position of the end face 10e of the optical film 10 and the position of the end face 21e of the pressure-sensitive adhesive layer 21 may be aligned, and the end face 21e of the pressure-sensitive adhesive layer 21 may be located inside the end face 10e of the optical film 10. As schematically shown in FIGS. 1 and 2, the pressure-sensitive adhesive layer 21 may have a cross-sectional shape in which the end surface 21e exists inside the end surface 10e of the optical film 10 near the center in the thickness direction. .. In addition to the end face 21e of the pressure-sensitive adhesive layer 21 being covered with the release film 41, the pressure-sensitive adhesive squeezing out from the end face tends to be further suppressed by being located inside the end face of the optical film 10. is there.

_{The distance Y 1} (maximum distance in the direction orthogonal to the thickness direction) between the end face 10e of the optical film 10 and the end face 21e of the pressure-sensitive adhesive layer 21 is preferably 5 μm or more, more preferably 10 μm or more, and 20 μm or more or 30 μm or more. You may. Y ₁ is generally 500 μm or less, and may be 300 μm or less, 200 μm or less, 100 μm or less, or 50 μm or less.

Distance Y ₄ between the end portion 4 of the end surface 21e of the pressure-sensitive adhesive layer 21 release film is preferably larger than the distance Y ₁ between the end surface 10e of the end surface 21e and the optical film 10 of the adhesive layer 21. That is, the end 4 of the release film is located outside the end face 10e of the optical film 10, and from the outside, the end 4 of the release film, the end face 10e of the optical film 10, and the end face of the adhesive layer 21. It is preferable that they are arranged in the order of 21e. Y _4- Y ₁ is preferably 10 μm or more, and may be 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. Y _4- Y ₁ is preferably 1 mm or less, more preferably 500 μm or less, and may be 300 μm or less, 200 μm or less, or 100 μm or less.

<End face processing of sheet sheet>
The adhesive-attached optical film in which the end portion of the release film covers the edge portion of the adhesive layer can be formed, for example, by cutting the end face of the adhesive-attached optical film with an end mill. If the cutting process is performed from the side surface, the adhesive layer 21 which is softer than the optical film 10 and the release film 41 is easily cut, so that a cross-sectional shape in which the end surface 21e of the adhesive layer 21 is located inside can be formed.

The type of end mill blade is not particularly limited, and may be appropriately selected from straight blades (ordinary blades), tapered blades, roughing blades, ball blades, radius blades, and the like. A straight blade is generally used for processing the end face.

FIG. 3 is a perspective view of the straight end mill 9. The cutting blade 91 of the end mill has a "right twist" that is twisted clockwise from the shank 92 side toward the cutting edge and a "left twist" that is twisted counterclockwise. The cutting blade of a general end mill has a right-handed twist. The right-twisted blade is used in a forward rotation (clockwise when viewed from the shank side) as shown by the arrow in FIG. The outer diameter of the cutting blade 91 is usually about 3 to 20 mm, the number of blades of the cutting blade 91 is usually 2 to 10, and the blade angle is usually 5 to 60 °.

As shown in FIG. 4, the end face of the work is cut by moving the end mill relative to the work while bringing the rotating end mill into contact with the work W to be cut. When the work W is located on the right side of the relative movement direction of the end mill (when the end mill 9 is relatively moved in the A direction of FIG. 4), cutting is performed so that the cutting blade digs the work inward (down cut). When the work W is located on the left side of the relative movement direction of the end mill (when the end mill 9 is relatively moved in the B direction of FIG. 4), cutting is performed so that the cutting blade scoops up the cutting surface of the work (upcut). ..

When the end milling process is performed with the release film 41 located above the pressure-sensitive adhesive layer 21, if the process is performed by down-cutting, the portion (end 4) formed by the cutting process of the release film 41 is on the lower side. The end portion 4 of the release film covers the end surface 21e of the pressure-sensitive adhesive layer 21. When end milling is performed with the release film 41 of the optical film with an adhesive located below the adhesive layer 21, if the processing is performed by up-cutting, the portion formed by the cutting process of the release film 41 ( Since the end portion 4) faces upward, the end portion 4 of the release film covers the end surface 21e of the pressure-sensitive adhesive layer 21. By adjusting the arrangement of the optical film with adhesive and the processing direction (downcut or upcut) in this way, the optical film with adhesive covers the end surface 21e of the release film 41 with the end portion of the release film 41. Is obtained.

Down-cutting is generally used for machining with an end mill, but in down-cutting, the work piece is machined while the cutting piece is wound inside, so the cutting piece easily adheres to the work piece. Since the main surface of the adhesive layer is covered with a release film, the adhesion of cutting pieces to the main surface does not directly cause product contamination, but the optical films with adhesive are stored in a stacked state. At that time, the cutting piece adhering to the release film may cause deformation such as dents. Since the upcut processes the work while discharging the cutting pieces to the outside, it is possible to reduce the adhesion of the cutting pieces to the work. Therefore, it is preferable to perform processing by up-cutting in a state where the release film 41 of the optical film with an adhesive is located under the adhesive layer 21.

When performing end mill processing, it is preferable to use a stack of a plurality of optical films with an adhesive cut out on a single sheet as a processing work W. The work W in which a plurality of optical films with adhesives are stacked may be sandwiched and fixed from above and below by a fixing means such as a clamp. The number of optical films with an adhesive constituting the work is, for example, about 5 to 200, preferably about 10 to 100. The total thickness of the work is about 1 to 150 mm, preferably 3 mm or more, and more preferably 5 mm or more.

When fixing the work, pressure may be applied from the upper and lower surfaces so that the adhesive layer protrudes from the end portion, and the cutting process may be performed by an end mill with the adhesive protruding. When the pressure is released after processing, the end face 21e of the pressure-sensitive adhesive layer 21 recedes inward. Therefore, as shown in FIGS. 1 and 2, the end face 21e of the pressure-sensitive adhesive layer 21 is inside the end face 10e of the optical film 10. An optical film with an adhesive located in can be produced.

The rotation speed of the end mill is, for example, 1000 to 100,000 rpm. The higher the rotation speed, the larger the coating length L of the end face of the pressure-sensitive adhesive layer 21 by the end 4 of the release film tends to be. This is because the higher the rotation speed, the rougher the machined surface, and the end portion of the release film 41 is likely to remain without being sufficiently cut, and the remaining portion of the release film 41 forms the end portion of the adhesive layer 21. It is thought that this is to cover it. Since such a remaining portion has a smaller thickness than that before processing, the thickness of the end portion 4 is temporarily attached to the main surface of the pressure-sensitive adhesive layer 21 as shown in FIGS. 1 and 2. It is smaller than the thickness of the film 41.

From the viewpoint of increasing the coating length L of the end face of the pressure-sensitive adhesive layer 21 by intentionally leaving a portion of the release film that has not been sufficiently cut, the rotation speed of the end mill is preferably 5000 rpm or more, more preferably 10,000 rpm or more. preferable. The rotation speed may be 15,000 rpm or more, 2000 rpm or more, 25,000 rpm or more, or 30,000 rpm or more.

For the same reason as described above, the larger the thickness (thickness before processing) of the release film 41, the more likely it is that a portion where the release film is insufficiently cut remains, and the adhesive layer 21 formed by the end 4 of the release film The coating length L of the end face tends to be large. In order to increase the coating length L of the end face of the pressure-sensitive adhesive layer 21, the thickness of the release film 41 is preferably 45 μm or more.

The relative moving speed of the end mill with respect to the work is about 100 to 10000 mm / min, and may be 300 mm / min or more or 500 mm / min or more, or 5000 mm / min or less or 1000 mm / min or less. In the relative movement, the position of the work may be fixed and the end mill may be moved, or the position of the end mill may be fixed and the work (milling machine with the work fixed) may be moved.

[Use of optical film with adhesive]
The optical film with an adhesive can be used for forming various image display devices. The first adhesive layer 21 provided on the first main surface of the optical film 10 is used for bonding to a front transparent member such as a cover window or a touch panel. As shown in FIG. 2, when the second adhesive layer 22 is provided on the second main surface of the optical film 10, the second adhesive layer 22 is, for example, an image display cell such as a liquid crystal cell or an organic EL cell. It is used for bonding with.

Even if an adherend such as a cover window is bonded onto the first pressure-sensitive adhesive layer 21, heat, pressurization, depressurization, or the like is performed in order to remove air bubbles at the bonding interface or near the printing step. Good. An autoclave process may be performed for the purpose of suppressing delay bubbles. When the first pressure-sensitive adhesive layer 21 is a photocurable pressure-sensitive adhesive, it is preferable that the first pressure-sensitive adhesive layer is photo-cured after the adherend is attached to the first pressure-sensitive adhesive layer 21. By photocuring the adhesive, the reliability of adhesion to the adherend is enhanced.

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Preparation of polarizing plate with adhesive]
<Adhesive sheet A>
Butyl acrylate (BA): 60 parts by weight, cyclohexyl acrylate (CHA): 20 parts by weight, 4-hydroxybutyl acrylate (4HBA): 20 parts by weight, and photopolymerization initiator (BASF "Irgacure 184") in the reaction vessel. ): 0.1 part by weight was added and irradiated with ultraviolet rays in a nitrogen atmosphere to obtain a prepolymer composition having a polymerization rate of 10%. In 100 parts by weight of this prepolymer composition, a photopolymerization initiator (“Irgacure 651” manufactured by BASF): 0.2 parts by weight, 1,6-hexanediol diacrylate as a polyfunctional monomer (“NK ester” manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) A-HD-N "): 0.3 parts by weight, α-thioglycerol as a chain transfer agent: 0.2 parts by weight, and silane coupling agent ("KBM-403 "manufactured by Shin-Etsu Chemical Co., Ltd.): 0.3 parts by weight. Was added and mixed uniformly to prepare a pressure-sensitive adhesive composition.

The above pressure-sensitive adhesive composition is applied to a release-treated surface of a release film having a thickness of 75 μm (a polyester film whose one side has been release-treated with silicone, “MRF75” manufactured by Mitsubishi Chemical Co., Ltd.) so as to have a thickness of 150 μm. A coating layer was formed, and a release-treated surface of a release film having a thickness of 38 μm was bonded onto the coating layer. After that, UV irradiation was performed with a black light whose position was adjusted so that the irradiation intensity on the irradiation surface directly under the lamp was 5 mW / cm ^{2 until the integrated light intensity became 3000 mJ / cm 2,} and the polymerization was allowed to proceed, and the mold was released on both sides. An adhesive sheet A to which the film was temporarily attached was obtained. The shear storage elastic modulus of the pressure-sensitive adhesive sheet A at a temperature of 25 ° C. was 120 kPa.

<Adhesive sheet B>
Using ethyl acetate as a solvent, 97 parts by weight of butyl acrylate (BA) and 3 parts by weight of acrylic acid (AA) are polymerized in the presence of a thermal polymerization initiator (AIBN), and the weight average molecular weight (Mw) is 110. A solution of 10,000 polymers was obtained. In this solution, with respect to 100 parts by weight of the polymer, trimethylolpropane tolylene diisocyanate (“Coronate L” manufactured by Tosoh): 0.8 parts by weight as an isocyanate-based cross-linking agent, and a silane coupling agent (“KBM-” manufactured by Shinetsu Chemical Co., Ltd.). 403 "): 0.1 part by weight was added and mixed uniformly to prepare a pressure-sensitive adhesive composition (solution). This composition is applied on the release-treated surface of a release film having a thickness of 38 μm (“MRF38” manufactured by Mitsubishi Chemical Co., Ltd.) so that the thickness after drying is 20 μm, and dried at 100 ° C. for 3 minutes to prepare a solvent. After removal, the release-treated surface of another release film is superposed on the pressure-sensitive adhesive layer, heated at 50 ° C. for 48 hours, cross-linked, and the release film is temporarily attached to both sides. Got

<Manufacturing of polarizing plate with adhesive>
An adhesive sheet A was attached to one surface of the polarizing plate using a roll laminator, and an adhesive sheet B was attached to the other surface to obtain a long polarizing plate with a double-sided adhesive. As the polarizing plate, a polarizing plate (total thickness 92 μm) in which an acrylic transparent protective film was bonded to both sides of a PVA polarizing element having a thickness of 20 μm was used. The polarizing plate with a double-sided adhesive had a laminated structure of a release film (75 μm) / adhesive sheet A (150 μm) / polarizing plate (92 μm) / adhesive sheet B (20 μm) / release film (38 μm).

[Comparative Example 1]
A polarizing plate with a double-sided adhesive was cut into a rectangle having a size of 65 mm × 140 mm using a super cutter (continuous automatic cutting machine).

[Example 1]
The polarizing plate with a double-sided pressure-sensitive adhesive of Comparative Example 1 was arranged so that the pressure-sensitive adhesive sheet A was on the lower side of the polarizing plate, and 50 sheets were stacked to prepare a working work having a thickness of about 20 mm. With this work sandwiched between clamps, the outer peripheral surface of the work was cut by end milling. For the end mill machining, a straight end mill with a blade angle of 45 ° was used, and the machining was performed by upcut at a rotation speed of 35,000 rpm and a feed rate (the relative moving speed of the work with respect to the end mill) of 1000 mm / min.

[Examples 2 and 3]
The rotation speed of the end mill was changed to 20000 rpm in Example 2 and 45000 rpm in Example 3. Other than that, the outer peripheral surface of the work was cut in the same manner as in Example 1.

[Comparative Example 2]
The outer peripheral surface of the work was cut in the same manner as in Example 1 except that the relative movement direction of the work with respect to the end mill was reversed and the work was performed by down-cutting.

[Comparative Example 3]
A polarizing plate with a double-sided adhesive was punched out to a size of 65 mm × 140 mm with a Thomson blade.

[Evaluation]
A polarizing plate with a double-sided adhesive is cut with a cutter knife in a direction parallel to the short side, and both ends of the cut surface with the cutter knife, that is, the cross section of the machined surface with the end mill is observed with an optical microscope to cover the end face of the adhesive sheet A. The length L of the release film was measured.

Table 1 shows the processing conditions of Examples 1 to 3 and Comparative Examples 1 to 3 and the coating length L of the release film on the end face.

In Comparative Example 1 and Comparative Example 3 in which the end milling was not performed after cutting, the positions of the end faces of the adhesive sheet A and the positions of the end faces of the release film temporarily attached on the end faces were almost aligned, and the end faces of the adhesive sheet A were substantially aligned. Was exposed. In Examples 1 to 3 in which the end milling process was performed by up-cutting with the adhesive sheet A located below the polarizing plate, the end portion of the release film protruded outward from the end surface of the adhesive sheet A. , The release film protruding outward covered the end face of the adhesive sheet A. From the comparison of Examples 1 to 3, it can be seen that the larger the rotation speed of the end mill, the larger the coating length L of the end face.

In Comparative Example 2 in which the end milling was performed by down-cutting, the end portion of the release film did not cover the end face of the adhesive sheet A, and the end face of the adhesive sheet A was exposed, as in Comparative Examples 1 and 3. From the comparison between Examples 1 to 3 and Comparative Example 2, in Examples 1 to 3, the release film arranged under the adhesive sheet A was cut so as to be wound up by the up-cut processing. It is considered that the end shape was formed so as to cover the end face of the adhesive sheet.

[Examples 4 to 7]
In Examples 4 to 7, the configuration of the polarizing plate with the double-sided adhesive was changed, and cutting and end milling with a super cutter were carried out under the same conditions as in Example 1. In Example 4, the thickness of the release film in contact with the pressure-sensitive adhesive sheet A was changed to 125 μm, and the thickness of the pressure-sensitive adhesive sheet A was changed to 500 μm. In Example 5, as the pressure-sensitive adhesive sheet A, a pressure-sensitive adhesive sheet having a shear storage elastic modulus G'at 70 kPa at 25 ° C. was used. In Example 6, a polarizing plate (total thickness 51 μm) in which an acrylic transparent protective film is bonded to both sides of a thin polarizing element having a thickness of 5 μm is used, and the adhesive sheet B has a shear storage elastic modulus G'at 80 kPa at 25 ° C. An adhesive sheet having a thickness of 15 μm was used. In Example 7, a release film having a thickness of 50 μm was used as the release film in contact with the pressure-sensitive adhesive sheet A.

Table 2 shows the configurations of the polarizing plates with double-sided adhesives of Examples 4 to 7 and the coating length L of the release film on the end face together with the results of Example 1. Further, an optical microscope image of a cross section of the pressure-sensitive adhesive polarizing plate of Example 4 is shown in FIG.

In Examples 4 to 7 in which the configuration of the polarizing plate with the double-sided adhesive is changed, the end portion of the release film projects outward from the end surface of the adhesive sheet A and covers the end surface of the adhesive sheet A, as in the case of Example 1. Was there. Regarding the coating length L, no clear difference was observed between Examples 5 and 6 from Example 1. In Example 4 in which the thickness of the release film was changed to 125 μm, the coating length L was larger than that in the example in Example 1 in which the thickness of the release film was 75 μm. On the other hand, in Example 7 in which the thickness of the release film in contact with the adhesive sheet was changed to 50 μm, the coating length L was small. From these results, it can be seen that the coating length L of the end face tends to increase by adjusting the thickness of the release film temporarily attached to the adhesive sheet.

10 Optical film 21,22 Adhesive layer 41,42 Release film 101,102 Optical film with adhesive 9 End mill

Claims (11)

1. Optical film with first and second main surfaces;
   A first pressure-sensitive adhesive layer fixed and laminated on the first main surface of the optical film; and a first release film covering the first pressure-sensitive adhesive layer and temporarily adhered to the first pressure-sensitive adhesive layer.
   An optical film with an adhesive that comprises
   The thickness of the first pressure-sensitive adhesive layer is 50 μm or more, and the thickness is 50 μm or more.
   An optical film with an adhesive, wherein the first release film covers the end face of the first adhesive layer in a range of 10% or more of the thickness of the first adhesive layer.
2. The optical film with an adhesive according to claim 1, wherein the thickness of the first release film is 45 μm or more.
3. The optical film with an adhesive according to claim 1 or 2, wherein the storage elastic modulus of the first adhesive layer at 25 ° C. is 0.35 MPa or less.
4. The optical film with an adhesive according to any one of claims 1 to 3, wherein the distance between the end portion of the first release film and the end surface of the first adhesive layer is 2 mm or less.
5. The one according to any one of claims 1 to 4, wherein the thickness of the end portion of the first release film is smaller than the thickness of the first release film temporarily adhered on the first pressure-sensitive adhesive layer. Optical film with adhesive.
6. The end face of the optical film is located inside the end of the release film.
   The optical film with an adhesive according to any one of claims 1 to 5, wherein the end face of the first pressure-sensitive adhesive layer is located inside the end face of the optical film.
7. In addition, a second pressure-sensitive adhesive layer and a second release film are provided.
   The second pressure-sensitive adhesive layer is fixedly laminated on the second main surface of the optical film.
   The pressure-sensitive optical film according to any one of claims 1 to 6, wherein the second release film covers the second pressure-sensitive adhesive layer and is temporarily adhered to the second pressure-sensitive adhesive layer.
8. The optical film with an adhesive according to claim 7, wherein the thickness of the second pressure-sensitive adhesive layer is smaller than the thickness of the first pressure-sensitive adhesive layer.
9. The optical film with an adhesive according to claim 7 or 8, wherein the thickness of the second release film is smaller than the thickness of the first release film.
10. The method for producing an optical film with an adhesive according to any one of claims 1 to 9.
    Including the process of cutting the end face of the optical film with adhesive cut out into a single sheet with an end mill.
    The cutting process
    The first release film is downcut with the first release film located above the first pressure-sensitive adhesive layer, or the first release film is located below the first pressure-sensitive adhesive layer. A method for manufacturing an optical film with an adhesive, which is carried out by up-cutting in a state.
11. The method for producing an optical film with an adhesive according to claim 10, wherein the cutting process is performed using a processing work in which a plurality of optical films with an adhesive cut out on a single sheet are stacked.
    
    

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