Laminate, laminate for film processing, and method for producing film

Abstract

The present invention provides a laminate and a laminate for film processing, especially a laminate for sensor film processing, which is suitable for use in the production of a sensor film, suppresses adhesive residue to the sensor film, and is not susceptible to loss of adhesion during and after sensor processing.　A laminate for sensor film processing according to the present invention is used for the formation of a sensor on a film, and comprises a laminate in which a film for sensor processing, a weakly adhesive layer, a base material, and an easily releasable adhesive layer are stacked in this order. The weakly adhesive layer does not have ultraviolet curability and has an adhesive force to glass of 2 N / 25 mm or less. The easily releasable adhesive layer has properties such that the adhesive force thereof is reduced when irradiated with ultraviolet light, and has an initial adhesive force to glass of 5 N / 25 mm or more and an adhesive force to glass measured under specific conditions of 1 N / 25 mm or less.

Description

Laminate, laminate for film processing, and method for producing film

[0001] The present invention relates to a laminate, a laminate for film processing, and a method for producing a film.

[0002] Sensor films used in touch panels and the like are produced by forming a conductive pattern on the surface of a base film (referred to herein as a sensor processing film) by means of, for example, photolithography.

[0003] The formation of a conductive pattern on a sensor processing film is carried out, for example, in a state in which the sensor processing film is fixed on a support. Various methods for fixing the sensor processing film on a support are known, for example, a method in which the sensor processing film is fixed to the support by an adhesive sheet having adhesive layers formed on both sides of a substrate is known (see, for example, Patent Document 1, etc.).

[0004] Japanese Patent Application Laid-Open No. 2022-183682

[0005] However, when a sensor processing film is fixed to a support using an adhesive sheet, there is a problem that adhesive residue remains on the sensor film when the sensor film formed by processing is separated from the support. In this regard, for example, a method of bonding the sensor processing film to the support using an adhesive whose adhesive strength is significantly reduced by external forces (such as ultraviolet light or heat) can be considered. However, even in this case, the adhesive has a higher adhesion to the film than to the support, resulting in the problem of adhesive residue remaining on the film. Furthermore, there is a problem that the sensor processing film may lift or peel off from the support due to the influence of heat, etc. during sensor processing.

[0006] The present invention has been made in view of the above, and aims to provide a laminate and a laminate for film processing, and in particular, a laminate for sensor film processing and a method for manufacturing a sensor film that are suitably used for producing sensor films, that suppress adhesive residue on the sensor film, and that are less likely to lift during sensor processing.

[0007] As a result of extensive research to achieve the above-mentioned object, the inventors discovered that the above-mentioned object can be achieved by using a laminate having an adhesive layer with specific adhesive properties, and thus completed the present invention.

[0008] That is, the present invention encompasses, for example, the subject matter described in the following items. Item 1: A laminate comprising a weak adhesive layer, a substrate, and an easily peelable adhesive layer laminated in this order, wherein the weak adhesive layer is not UV-curable and has an adhesive strength to glass of 2 N / 25 mm or less as measured in Glass Adhesion Strength Measurement 1 described below, and the easily peelable adhesive layer has a property of decreasing adhesive strength by irradiation with UV light, and the easily peelable adhesive layer has an initial adhesive strength to glass of 5 N / 25 mm or more and an adhesive strength to glass of 1 N / 25 mm or less as measured in Glass Adhesion Strength Measurement 2 described below. <Glass Adhesion Strength Measurement 1> A test specimen in which the weak adhesive layer was attached to soda glass with a pressure of 2 kg and 24 hours had passed was subjected to a heat treatment at 100°C for 1 hour and then at 130°C for 5 minutes, in this order, and then a UV LED (365 nm) was used to measure 800 mJ / cm at 180 mW. ２ The adhesive strength of the weak adhesive layer is measured when peeled at 180° at a peeling speed of 300 mm / min, to obtain the adhesive strength to glass. <Measurement of adhesive strength to glass 2> A test specimen 24 hours after the easy-peel adhesive layer of the laminate was attached to the soda glass with a pressure of 2 kg was subjected to a heat treatment at 100°C for 1 hour and then a heat treatment at 130°C for 5 minutes in this order, and then a UV LED (365 nm) was used to irradiate the test specimen with 800 mJ / cm at 180 mW. ２100 nm of ultraviolet light is irradiated from the soda glass side. Thereafter, the adhesive strength is measured when the laminate included in the test specimen is peeled off from the soda glass at an angle of 180° at a peeling speed of 300 mm / min, to obtain the adhesive strength value of the easily peelable adhesive layer to glass. Item 2: A laminate for film processing comprising the laminate according to Item 1, used for film processing, the laminate further comprising a processing film on the surface of the weak adhesive layer opposite the substrate. Item 3: The laminate for film processing according to Item 2, wherein the processing film is a sensor processing film, and the film processing is sensor processing. Item 4: The laminate for film processing according to Item 3, wherein the sensor processing film is an ultraviolet-blocking film that blocks 90% or more of ultraviolet light with a wavelength of 370 nm. Item 5: The laminate for film processing according to Item 3 or 4, wherein the main component contained in the sensor processing film is the same as the main component contained in the substrate. Item 6. The laminate for film processing according to any one of Items 2 to 5, wherein a release sheet is bonded to a surface of the easily peelable adhesive layer opposite to the substrate. Item 7. A method for producing a sensor film using the laminate for film processing according to any one of Items 2 to 6, comprising: Step A of bonding the surface of the laminate with the easily peelable adhesive layer to a support to form a laminate with a support; Step B of processing the processing film of the laminate with a support to form a sensor on the processing film; Step C of irradiating ultraviolet light from the support side of the laminate with a support on which the sensor has been formed, and then peeling the support and the easily peelable adhesive layer to obtain a laminate with a sensor film; and Step D of peeling the sensor film from the laminate with a sensor film.

[0009] The laminate for sensor film processing according to the present invention is suitably used for producing a sensor film, and is less likely to leave adhesive residue on the sensor film and to lift off during sensor processing.

[0010] 1 is a schematic cross-sectional view showing an example of an embodiment of the laminate for sensor film processing of the present invention. FIG. 2 is a schematic flow diagram showing an example of a method for producing a sensor film using the laminate for sensor film processing of the present invention.

[0011]

[0023] In the present specification, the terms "contain" and "comprise" include the concepts of "contain," "comprise," "consist essentially of," and "consist only of."

[0012] 1. Laminate and Laminate for Film Processing The laminate of the present invention comprises a weak adhesive layer, a substrate, and an easily peelable adhesive layer laminated in this order, the weak adhesive layer not being UV-curable and having an adhesive strength to glass of 2 N / 25 mm or less as measured by Glass Adhesion Strength Measurement 1 described below, the easily peelable adhesive layer having a property of decreasing adhesive strength upon irradiation with UV light, the easily peelable adhesive layer having an initial adhesive strength to glass of 5 N / 25 mm or more and an adhesive strength to glass of 1 N / 25 mm or less as measured by Glass Adhesion Strength Measurement 2 described below. The laminate for film processing of the present invention is used for film processing and comprises a laminate comprising a processing film, a weak adhesive layer, a substrate, and an easily peelable adhesive layer laminated in this order. In such a laminate, the weak adhesive layer is not UV-curable and has an adhesive strength to glass of 2 N / 25 mm or less as measured by Glass Adhesion Strength Measurement 1 described below, and the easily peelable adhesive layer has the property of decreasing adhesive strength upon irradiation with UV light, and the easily peelable adhesive layer has an initial adhesive strength to glass of 5 N / 25 mm or more and an adhesive strength to glass of 1 N / 25 mm or less as measured by Glass Adhesion Strength Measurement 2 described below. The processing film can be any of a variety of films, such as a sensor processing film. When the processing film is a sensor processing film, the film processing laminate of the present invention is used to form a sensor on the film, and therefore the laminate or film processing laminate of the present invention can be referred to as a "sensor film processing laminate."

[0013] After the laminate for film processing of the present invention is fixed on a support, the processing film can be appropriately processed. During this processing, the laminate is unlikely to lift off from the support, making it easy to produce a high-quality processing film. Furthermore, when the resulting processing film is peeled off, the occurrence of adhesive residue on the processing film is also suppressed. When the film processing laminate is the aforementioned sensor film processing laminate, a sensor can be formed on the sensor processing film by fixing the sensor film processing laminate on a support and then performing sensor processing on the sensor processing film, thereby producing a sensor film. During this processing, the laminate is unlikely to lift off from the support, making it easy to produce a high-quality sensor film. Furthermore, when the resulting sensor film (meaning the sensor processing film on which a sensor is formed) is peeled off, the occurrence of adhesive residue on the sensor film is also suppressed.

[0014] Fig. 1 is a schematic cross-sectional view showing one example of an embodiment of the laminate for sensor film processing of the present invention. As shown in Fig. 1, the laminate for sensor film processing of the present invention is formed by laminating a sensor processing film 1, a weak adhesive layer 2, a substrate 3, and an easily peelable adhesive layer 4 in this order to form a laminate A (laminate for sensor film processing). As shown in Fig. 1, the layers of the sensor processing film 1, the weak adhesive layer 2, the substrate 3, and the easily peelable adhesive layer 4 are directly bonded to each other.

[0015] The sensor processing film and each layer of the laminate including the film will be described in detail below. (Sensor processing film) The sensor processing film is a film for forming a sensor. That is, the sensor processing film is a layer that becomes a sensor film when a sensor is formed. The type of such sensor processing film is not particularly limited, and for example, various films that have conventionally been used to manufacture sensor films can be widely used.

[0016] The sensor processing film may be a transparent resin film. That is, the sensor processing film may be a transparent film whose main component is a resin. In this specification, the main component means 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more of the total mass of all components.

[0017] Examples of such a sensor processing film include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate, polycarbonate resins, norbornene resins (COP), etc. In particular, a film having an extremely large retardation can be preferably used as the sensor processing film in terms of facilitating improved visibility, and so-called super birefringent films are preferred examples of the sensor processing film.

[0018] Examples of the super birefringent film include super birefringent polyester films, and particularly preferred examples include super birefringent PET films, such as "Cosmoshine SRF (registered trademark)" manufactured by Toyobo Co., Ltd.

[0019] An easy-adhesion layer may be formed on at least one surface of the sensor processing film. The type of easy-adhesion layer is not particularly limited, and a wide variety of known easy-adhesion layers can be used.

[0020] It is also preferable that the sensor processing film is an ultraviolet-cutting film that blocks 90% or more of ultraviolet light with a wavelength of 370 nm. In this case, the durability of the sensor film formed from the sensor processing film is improved, and as will be described later, the sensor film is less likely to be damaged even if it is irradiated with ultraviolet light during production. An example of an ultraviolet-cutting film that blocks 90% or more of ultraviolet light with a wavelength of 370 nm is the aforementioned "Cosmoshine SRF (registered trademark)" manufactured by Toyobo Co., Ltd.

[0021] The thickness of the sensor processing film is not particularly limited and may be the same as that of conventional films used to form sensors. For example, the thickness of the sensor processing film is usually 10 to 300 μm, and preferably 20 to 200 μm.

[0022] (Weakly adhesive layer) The weakly adhesive layer is a layer for exerting an adhesive function and is a layer for bonding a processing film such as a sensor processing film. The weakly adhesive layer is not UV-curable, and has a glass adhesion strength of 2 N / 25 mm or less as measured by the following Glass Adhesion Strength Measurement 1. <Glass Adhesion Strength Measurement 1> The weakly adhesive layer exposed by peeling the sensor processing film from the laminate was bonded to soda glass with a pressure of 2 kg, and 24 hours had passed since then. A test specimen was subjected to a heat treatment at 100°C for 1 hour and then at 130°C for 5 minutes, in that order. After that, a UV LED (365 nm) was used to measure the glass adhesion strength of 800 mJ / cm at 180 mW. ２ The adhesive strength of the weak adhesive layer is measured when the layer is peeled off at an angle of 180° at a peeling speed of 300 mm / min to obtain the adhesive strength to glass.

[0023] When the adhesive strength of the weak adhesive layer to glass measured by Glass Adhesion Strength Measurement 1 is 2 N / 25 mm or less, the adhesive strength is unlikely to change even when processed at high temperatures such as during sensor processing, and the heat resistance is excellent. As a result, the adhesive strength is maintained even during sensor processing, and in addition, adhesive residue is unlikely to remain on the sensor film even when the sensor film is peeled off after sensor processing is completed. When the adhesive strength of the weak adhesive layer to glass measured by Glass Adhesion Strength Measurement 1 exceeds 2 N / 25 mm, adhesive residue is likely to remain on the processed film (e.g., sensor film) after peeling.

[0024] The adhesive strength of the weak adhesive layer to glass, as measured by Glass Adhesion Strength Measurement 1, is preferably 1.5 N / 25 mm or less, more preferably 1 N / 25 mm or less, and even more preferably 0.6 N / 25 mm or less, and is preferably 0.01 N / 25 mm or more, more preferably 0.05 N / 25 mm or more, and even more preferably 0.1 N / 25 mm or more.

[0025] The type of the weak adhesive layer is not particularly limited as long as the adhesive strength to glass is 2 N / 25 mm or less, and the layer can be formed using, for example, a known adhesive. Such an adhesive is referred to as a "weak adhesive layer-forming adhesive."

[0026] As the adhesive for forming the weak adhesive layer, various adhesives can be used as long as they are not UV-curable, and for example, they can contain a known acrylic polymer and a crosslinking agent.

[0027] An acrylic polymer is, for example, a polymer composed of (meth)acrylic monomer units. In this specification, "(meth)acrylic" means "acrylic" or "methacrylic", "(meth)acrylate" means "acrylate" or "methacrylate", and "(meth)allyl" means "allyl" or "methallyl".

[0028] The type of acrylic polymer is not particularly limited, and examples thereof include polymers of a (meth)acrylic acid ester and a monomer having a crosslinkable functional group that is copolymerizable with the (meth)acrylic acid ester. That is, the acrylic polymer can contain (meth)acrylic acid ester units and monomer units having a crosslinkable functional group.

[0029] Examples of (meth)acrylic acid esters include (meth)acrylates having a linear, branched, or cyclic alkyl group, and (meth)acrylates having an aromatic ring. When the (meth)acrylate has a linear, branched, or cyclic alkyl group, the number of carbon atoms therein can be, for example, 1 to 20, preferably 1 to 15, and more preferably 1 to 10. When the (meth)acrylate has an aromatic ring, the number of carbon atoms therein can be, for example, 5 to 20, preferably 6 to 10. Specific examples of (meth)acrylic acid ester monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isopropyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, and benzyl (meth)acrylate.

[0030] Among these, the (meth)acrylic acid ester is preferably at least one selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isopropyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and cyclohexyl (meth)acrylate.

[0031] The (meth)acrylic acid ester unit contained in the acrylic polymer may be one type alone or two or more types. The (meth)acrylic acid ester unit contained in the acrylic polymer may include two or more types selected from (meth)acrylates having a linear alkyl group, (meth)acrylates having a branched group, and (meth)acrylates having a cyclic alkyl group.

[0032] The monomer having a crosslinkable functional group may be a polymerizable compound having a crosslinkable functional group in the molecule. The type of the crosslinkable functional group is not particularly limited, and examples thereof include a carboxyl group, a hydroxyl group, an amino group, and a glycidyl group.

[0033] Examples of the monomer having a crosslinkable functional group include the (meth)acrylate having the crosslinkable functional group. Hereinafter, the (meth)acrylate having the crosslinkable functional group will be referred to as a "(meth)acrylate containing a crosslinkable functional group."

[0034] Examples of the crosslinkable functional group-containing (meth)acrylate for forming the crosslinkable functional group-containing (meth)acrylate unit include a carboxyl group-containing (meth)acrylate unit, a hydroxy group-containing (meth)acrylate unit, an amino group-containing (meth)acrylate unit, and a glycidyl group-containing (meth)acrylate unit.

[0035] Examples of the carboxyl group-containing (meth)acrylate include acrylic acid and methacrylic acid. Examples of the hydroxy group-containing (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2,2-dimethyl-2-hydroxyethyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, and polyalkylene glycol mono(meth)acrylate.

[0036] The crosslinkable functional group-containing (meth)acrylate preferably contains at least one selected from the group consisting of carboxyl group-containing (meth)acrylates and hydroxy group-containing (meth)acrylates.

[0037] In the acrylic polymer, the content ratio of (meth)acrylic acid ester units and monomer units having a crosslinkable functional group is not particularly limited. The acrylic polymer preferably contains 40% by mass or more of (meth)acrylic acid ester units, more preferably 50% by mass or more, even more preferably 60% by mass or more, and particularly preferably 65% ​​by mass or more, and also preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and particularly preferably 80% by mass or less. In these cases, the remaining monomer units of the acrylic polymer are preferably monomer units having a crosslinkable functional group, and are preferably carboxyl group-containing (meth)acrylate units and / or hydroxy group-containing (meth)acrylate units.

[0038] The acrylic polymer may contain other monomer units other than those described above, as long as the effects of the present invention are not impaired. The content of the other monomer units may be 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less. The acrylic polymer may be composed only of (meth)acrylic acid ester units and monomer units having a crosslinkable functional group. The proportion (molar ratio) of each structural unit in the acrylic polymer can be considered to be the same as the molar ratio of each monomer used in producing the polymer.

[0039] The weight average molecular weight of the acrylic polymer is not particularly limited, and can be, for example, from the viewpoint that the adhesive strength of the pressure-sensitive adhesive sheet is less likely to decrease, and is preferably from 100,000 to 2,000,000, and more preferably from 300,000 to 1,000,000.

[0040] The weight-average molecular weight referred to in the present invention refers to the weight-average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC). There are no particular limitations on the GPC apparatus used in the GPC method, and commercially available GPC measuring instruments, such as the LC-2000Plus series manufactured by JASCO Corporation, and detectors such as RI-2031Plus and UV-2075Plus, can be used. In this case, for example, a GPC column consisting of four columns connected together, namely, "Shodex KF801," "Shodex KF803L," "Shodex KF800L," and "Shodex KF800D" manufactured by Showa Denko K.K., can be used. The column temperature can be set to 40°C. Tetrahydrofuran is used as the eluent, and measurements are performed at a flow rate of 1.0 ml / min. Typically, a calibration curve is prepared using standard polystyrene, and the weight-average molecular weight (Mw) can be obtained in terms of polystyrene.

[0041] The type of crosslinking agent contained in the adhesive for forming a weak adhesive layer is not particularly limited, and for example, a wide variety of known crosslinking agents can be used. Examples of crosslinking agents include a wide variety of components that can promote crosslinking of acrylic polymers. In particular, examples of crosslinking agents include a wide variety of components that can react with hydroxyl groups and / or carboxyl groups in the acrylic polymers. Examples of such crosslinking agents include a wide variety of known crosslinking agents, such as isocyanate crosslinking agents and epoxy crosslinking agents.

[0042] The type of isocyanate crosslinking agent is not particularly limited, and a wide variety of known compounds can be used. Examples of isocyanate crosslinking agents include polyisocyanates such as tolylene diisocyanate, chlorophenylene diisocyanate, diphenylmethane diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and xylylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate and cyclohexylene diisocyanate; and aromatic isocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and 4,4'-diphenylmethane diisocyanate. The isocyanate crosslinking agents can be used alone or in combination of two or more different types. It is more preferable to use trifunctional derivatives, such as adducts, nurates, and biurets, obtained from the above-mentioned diisocyanates as the isocyanate crosslinking agent.

[0043] The type of epoxy crosslinking agent is not particularly limited, and a wide variety of known compounds can be used. Examples of epoxy crosslinking agents include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexanone, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, and sorbitol polyglycidyl ether.

[0044] The adhesive for forming the weak adhesive layer preferably contains 5 to 30 parts by mass, more preferably 8 to 20 parts by mass, of the crosslinking agent. This makes it easy to adjust the storage modulus (described later) within a preferred range, and forms a weak adhesive layer that combines heat resistance and adhesive strength. This maintains adhesive strength even during various processing steps such as sensor processing, and makes it less likely for adhesive residue to remain on the processed film (sensor film) when it is peeled off after processing such as sensor processing is completed.

[0045] The adhesive for forming the weak adhesive layer does not have UV curing ability. In this case, a weak adhesive layer that does not have UV curing ability can be formed using the adhesive for forming the weak adhesive layer. Since the weak adhesive layer that does not have UV curing ability is less likely to harden when exposed to UV light, as described below, it is prevented from being attached to the processing film more firmly than necessary when exposed to UV light, and adhesive residue on the processed film (sensor film) is more likely to be suppressed. The fact that the adhesive for forming the weak adhesive layer does not have UV curing ability means that the adhesive for forming the weak adhesive layer does not contain components that harden when exposed to UV light, such as polymerizable double bonds and photopolymerization initiators, and in particular does not contain radical polymerizable monomers and photopolymerization initiators. In other words, the fact that the weak adhesive layer does not have UV curing ability can be interpreted as meaning that the weak adhesive layer does not contain radical polymerizable monomers and photopolymerization initiators.

[0046] The adhesive for forming the weak adhesive layer can contain a solvent to improve coating properties.The type of solvent is not particularly limited, and examples thereof include hydrocarbons such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; halogenated hydrocarbons such as dichloromethane, trichloroethane, trichloroethylene, tetrachloroethylene, and dichloropropane; alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol, isobutyl alcohol, and diacetone alcohol; ethers such as diethyl ether, diisopropyl ether, dioxane, and tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, and cyclohexanone; esters such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, and ethyl butyrate; polyols and derivatives thereof such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monomethyl ether acetate.

[0047] When the adhesive for forming the weak adhesive layer contains a solvent, the content thereof is not particularly limited, and can be, for example, 25 to 500 parts by mass, and more preferably 30 to 400 parts by mass, per 100 parts by mass of the acrylic polymer.

[0048] The method for forming the weak adhesive layer is not particularly limited, and examples thereof include a method of applying the adhesive for forming the weak adhesive layer and then heat-treating the applied adhesive. This heat treatment and post-heat-treatment curing process promote the reaction between the acrylic polymer and the crosslinking agent, resulting in the formation of a crosslinked acrylic polymer.

[0049] The storage modulus of the weak adhesive layer at 100°C is preferably 100 kPa or more, more preferably 300 kPa or more. In this case, the weak adhesive layer is less likely to leave adhesive residue on the sensor film even when the sensor film is peeled off after sensor processing is completed. The storage modulus of the weak adhesive layer at 100°C is, for example, preferably 2000 kPa or less, more preferably 1500 kPa or less.

[0050] The gel fraction of the weak adhesive layer is preferably 70% or more, more preferably 85% or more, so that the weak adhesive layer is less likely to leave adhesive residue on the processed film (sensor film) when the processed film is peeled off after processing such as sensor processing is completed.

[0051] The thickness of the weak adhesive layer is, for example, preferably 5 μm or more, and is preferably 200 μm or less, and more preferably 100 μm or less.

[0052] (Substrate) The substrate serves to support the weak adhesive layer and the easily peelable adhesive layer, and its type is not particularly limited. Examples of the substrate include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate; polycarbonate resins; norbornene resins (COP); as well as polyacrylic resins, polyolefin resins, vinyl chloride, ABS, etc.

[0053] In particular, the substrate is preferably the same as the main component contained in the film for sensor processing. That is, in the present invention, the main component contained in the film for sensor processing and the main component contained in the substrate are preferably the same. In this case, it is possible to particularly suppress curling of the laminate or sensor film after sensor processing, and a high-quality sensor film can be efficiently obtained.

[0054] Therefore, the substrate can preferably be a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate; a polycarbonate resin; a norbornene resin (COP); etc., and among these, a superbirefringent film such as a superbirefringent polyester film is preferred, and a superbirefringent PET film is more preferred. A particularly preferred combination of the sensor processing film and the substrate is a superbirefringent PET film.

[0055] An easy-adhesion layer may be formed on at least one surface of the substrate. The type of the easy-adhesion layer is not particularly limited, and a wide variety of known easy-adhesion layers can be used.

[0056] The thickness of the substrate is not particularly limited, and is, for example, preferably 20 μm or more, more preferably 50 μm or more, and is preferably 200 μm or less, more preferably 150 μm or less.

[0057] (Easy-peel adhesive layer) The easy-peel adhesive layer is a layer for exerting an adhesive function and for fixing the laminate to a support described later. The easy-peel adhesive layer has the property of decreasing adhesive strength by irradiation with ultraviolet light. Specifically, the easy-peel adhesive layer has an initial adhesive strength to glass of 5 N / 25 mm or more and an adhesive strength to glass measured in the following glass adhesive strength measurement 2 of 1 N / 25 mm or less. <Glass adhesive strength measurement 2> A test specimen in which the easy-peel adhesive layer of the laminate was attached to soda glass with a pressure of 2 kg and then 24 hours later was subjected to a heat treatment at 100°C for 1 hour and then at 130°C for 5 minutes, in this order. After that, a UV LED (365 nm) was used to measure the adhesive strength of the laminate at 180 mW and 800 mJ / cm. ２ The laminate included in the test specimen is then peeled from the soda glass at an angle of 180° at a peeling speed of 300 mm / min, and the adhesive strength is measured to obtain the adhesive strength of the easily peelable adhesive layer to glass.

[0058] The initial adhesive strength to glass of the easily peelable adhesive layer refers to a state before the treatment to be performed in Glass Adhesion Strength Measurement 2. A test specimen for measuring such initial adhesive strength to glass can be obtained by bonding the easily peelable adhesive layer of the laminate to soda glass with a pressure of 2 kg.

[0059] When the initial adhesive strength to glass of the easily peelable adhesive layer is 5 N / 25 mm or more and the adhesive strength to glass measured in the following Glass Adhesion Strength Measurement 2 is 1 N / 25 mm or less, the easily peelable adhesive layer is firmly attached to the support before UV irradiation, and the laminate can be easily peeled from the support by UV irradiation. In this case, lifting of the laminate from the support during sensor processing can be suppressed, and curling of the laminate or sensor film after sensor processing can be particularly suppressed, allowing a high-quality sensor film to be efficiently obtained. When the initial adhesive strength to glass of the easily peelable adhesive layer is below 5 N / 25 mm, lifting of the laminate from the support is likely to occur during sensor processing.

[0060] The initial adhesive strength to glass of the easily peelable adhesive layer is preferably 6 N / 25 mm or more, more preferably 7 N / 25 mm or more, and even more preferably 8 N / 25 mm or more, and is preferably 40 N / 25 mm or less, more preferably 30 N / 25 mm or less, and even more preferably 25 N / 25 mm or less.

[0061] The adhesive strength to glass of the easily peelable adhesive layer measured in Glass Adhesion Strength Measurement 2 is preferably 1 N / 25 mm or less, more preferably 0.5 N / 25 mm or less, and is preferably 0.01 N / 25 mm or more, more preferably 0.05 N / 25 mm or more.

[0062] The easily peelable adhesive layer is not particularly limited as long as it has the property of reducing adhesive strength by irradiation with ultraviolet light, and can be formed, for example, from a known adhesive capable of forming an adhesive layer having such a property. Such an adhesive is referred to as an adhesive for forming an easily peelable adhesive layer.

[0063] Examples of adhesives for forming easily peelable adhesive layers include components that harden when irradiated with ultraviolet light or the like or by heating, specifically components whose adhesive strength decreases when irradiated with ultraviolet light or a laser, and components whose adhesive strength decreases when irradiated with heat. Among these, components whose adhesive strength decreases when irradiated with ultraviolet light or a laser are preferred. Components that harden when irradiated with ultraviolet light or the like (components whose adhesive strength decreases when irradiated with ultraviolet light or a laser) can be broadly divided into components containing a reactive double bond as a polyfunctional or oligomer, and components in which a reactive double bond has been introduced into a polymer. From the viewpoints of ease of production and heat resistance, the adhesive for forming easily peelable adhesive layers is more preferably the latter, a polymer in which a reactive double bond has been introduced.

[0064] Examples of polymers having reactive double bonds introduced therein include polymers having radically polymerizable double bonds, and among these, acrylic polymers having radically polymerizable double bonds are preferred. Known polymers can be used as the acrylic polymers having radically polymerizable double bonds. Commercially available examples of such acrylic polymers include "ELX-6151YF" and "ELX-6520" manufactured by Resonac Corporation.

[0065] The polymer into which the reactive double bond has been introduced may or may not contain an acid component.

[0066] The adhesive for forming the easily peelable adhesive layer may contain a crosslinking agent. Examples of the crosslinking agent include the same types as those contained in the adhesive for forming the weak adhesive layer described above. That is, examples thereof include the above-mentioned isocyanate crosslinking agent, epoxy crosslinking agent, etc.

[0067] The content of the crosslinking agent in the pressure-sensitive adhesive for forming an easily peelable pressure-sensitive adhesive layer is not particularly limited. For example, the crosslinking agent may be contained in an amount of 0.01 to 2 parts by mass, and more preferably 0.05 to 1.8 parts by mass, per 100 parts by mass of the polymer having the reactive double bond introduced therein.

[0068] The adhesive for forming the easily peelable adhesive layer may also contain a photopolymerization initiator. As the photopolymerization initiator, for example, a wide variety of known photopolymerization initiators can be used. The photopolymerization initiator is not particularly limited, and examples thereof include acetophenone-based photopolymerization initiators such as 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-[4-(2-hydroxyethoxyl)-phenyl]-2-hydroxy-methylpropanone, and 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methyl-1-propanone; acylphosphine oxide-based photopolymerization initiators such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 2,4,6-trimethylbenzoyl)phenylphosphine oxide; intramolecular hydrogen abstraction photopolymerization initiators such as methyl benzoylformate and 4-methylbenzophenone; and oil-soluble polymerization initiators such as oxime ester-based photopolymerization initiators and cationic photopolymerization initiators. Among these, the photopolymerization initiator is preferably at least one selected from the group consisting of acetophenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and oxime ester-based photopolymerization initiators.

[0069] Commercially available acetophenone-based photopolymerization initiators include EsacureOne (oligo(2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenylpropanone], manufactured by IGM Resins B.V.), Omnirad 651 (2,2-dimethoxy-2-phenylacetophenone, manufactured by IGM Resins B.V.), Omnirad 184 (1-hydroxycyclohexylphenyl ketone, manufactured by IGM Resins B.V.), and Omnirad 1173 (2-hydroxy-2-methyl-1-phenylpropanone, manufactured by IGM Resins B.V.).

[0070] Commercially available acylphosphine oxide photopolymerization initiators include Omnirad 819 (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, manufactured by IGM RESINS B.V.) and Omnirad TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide, manufactured by IGM RESINS B.V.). Commercially available oxime ester photopolymerization initiators include Irgacure OXE01 (1,2-octanedione, 1-[4-(phenylthio)phenyl[-, 2-(o-benzoyloxime) manufactured by BASF) and Irgacure OXE02 (ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) manufactured by BASF).

[0071] Other examples of the photopolymerization initiator include benzoin ether initiators, benzophenone initiators, hydroxyalkylphenone initiators, thioxanthone initiators, and amine initiators.

[0072] The content of the photopolymerization initiator in the pressure-sensitive adhesive for forming an easily peelable pressure-sensitive adhesive layer is not particularly limited. For example, the photopolymerization initiator may be contained in an amount of 0.01 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the polymer having the reactive double bond introduced therein.

[0073] The adhesive for forming the easily peelable adhesive layer may contain a solvent to improve coating properties. The type of solvent is the same as the type of solvent that can be contained in the adhesive for forming the weak adhesive layer described above.

[0074] When the adhesive for forming the easily peelable adhesive layer contains a solvent, the content thereof is not particularly limited, and can be, for example, 25 to 500 parts by mass, and more preferably 30 to 400 parts by mass, per 100 parts by mass of the acrylic polymer.

[0075] The method for forming the easily peelable adhesive layer is not particularly limited, and the easily peelable adhesive layer can be formed, for example, by applying the adhesive for forming the easily peelable adhesive layer and then performing a heat drying treatment. This heat treatment and aging after the heat treatment cause the reaction between the acrylic polymer and the crosslinking agent to proceed, forming a crosslinked acrylic polymer. Meanwhile, the photopolymerization initiator contained in the adhesive for forming the easily peelable adhesive layer remains in the easily peelable adhesive layer.

[0076] The storage modulus of the easily peelable adhesive layer at 25°C before UV irradiation is preferably 50 to 300 kPa, more preferably 70 to 200 kPa. In this case, lifting of the laminate from the support during sensor processing can be particularly suppressed, and curling of the laminate or sensor film after sensor processing can be particularly suppressed, allowing a high-quality sensor film to be obtained efficiently.

[0077] Furthermore, the tan δ at 100°C of the easily peelable adhesive layer before UV irradiation is preferably 0.1 or more. In this case, lifting of the laminate from the support during sensor processing can be particularly suppressed, and curling of the laminate or sensor film after sensor processing can be particularly suppressed, allowing a high-quality sensor film to be efficiently obtained. The tan δ at 100°C of the easily peelable adhesive layer before UV irradiation can be 1.2 or less, preferably 1.0 or less, and more preferably 0.7 or less.

[0078] The thickness of the easily peelable adhesive layer is, for example, preferably 5 μm or more, more preferably 10 μm or more, and is preferably 200 μm or less, more preferably 100 μm or less.

[0079] (Laminate for Film Processing) The laminate for film processing of the present invention is used for film processing, and further comprises a processing film on the surface of the weak adhesive layer opposite the substrate. That is, the laminate for film processing of the present invention is composed of a processing film, a weak adhesive layer, a substrate, and an easily peelable adhesive layer laminated in this order. Furthermore, the laminate for sensor film processing of the present invention is used for sensor processing, and further comprises a sensor processing film on the surface of the weak adhesive layer opposite the substrate. That is, the laminate for sensor film processing of the present invention is composed of a sensor processing film, a weak adhesive layer, a substrate, and an easily peelable adhesive layer laminated in this order. The laminate for sensor film processing of the present invention preferably consists of only a sensor processing film, a weak adhesive layer, a substrate, and an easily peelable adhesive layer, as shown in FIG. 1.

[0080] 1, the laminate for sensor film processing of the present invention preferably has a release sheet 5 attached to the surface of the easily peelable adhesive layer 4 opposite to the substrate 3. In this case, the easily peelable adhesive layer of the laminate is protected by the release sheet.

[0081] Examples of the release sheet include a release laminate sheet having a release sheet substrate and a release agent layer provided on one side of the release sheet substrate, or a polyolefin film such as a polyethylene film or a polypropylene film as a low-polarity substrate. Paper or a polymer film is used as the release sheet substrate in the release laminate sheet. Examples of the release agent constituting the release agent layer include general-purpose addition-type or condensation-type silicone-based release agents and long-chain alkyl group-containing compounds. Commercially available release laminate sheets may also be used. Examples include a heavy separator film, which is a release-treated polyethylene terephthalate film manufactured by Toyobo Co., Ltd.; a light separator film, which is a release-treated polyethylene terephthalate film manufactured by Oji F-Tex Co., Ltd.; and an antistatic light separator "50E-0010KF AS" manufactured by Fujimori Kogyo Co., Ltd.

[0082] In the laminate for sensor film processing of the present invention, the film for sensor processing in the laminate may be provided with a protective film or a hard coat layer, if necessary.

[0083] The method for producing the laminate for sensor film processing of the present invention is not particularly limited, and for example, a wide variety of known lamination methods can be adopted. An example of the method for producing the laminate for sensor film processing of the present invention will be described below.

[0084] The laminate for sensor film processing of the present invention can be obtained, for example, by a manufacturing method comprising: step 1 of forming a weak adhesive layer on a first release sheet; step 2 of laminating a substrate on the weak adhesive layer and then curing the layer; step 3 of forming an easily peelable adhesive layer on a second release sheet; step 4 of laminating the easily peelable adhesive layer and the substrate on which the weak adhesive layer has been formed; and step 5 of peeling off the first release sheet provided on the weak adhesive layer and then laminating a sensor processing film to the exposed weak adhesive layer.

[0085] In the above step 1, a weak adhesive layer is formed on the first release sheet, but instead of the first release sheet, a weak adhesive layer may be formed on the substrate, and the sensor processing film may be laminated and then cured. That is, the weak adhesive layer may be formed directly on the substrate. In this case, step 5 is unnecessary, and the total number of steps can be reduced. On the other hand, it is preferable to produce the sensor film processing laminate of the present invention through steps 1 and 5, in order to make it easier to peel off the sensor processing film of the resulting laminate.

[0086] In the above manufacturing method, the first release sheet and the second release sheet used in step 1 and step 3 may be the same or different. The release sheet used in step 1 is preferably a light release sheet. In this case, some of the silicon contained in the light release sheet may be transferred to the weak adhesive layer, which makes it possible to further reduce the adhesive strength of the weak adhesive layer to the sensor processing film.

[0087] In step 2, when laminating the substrate on the weak adhesive layer, if the easy-adhesion layer is formed on the substrate, it is preferable to laminate the surface of the easy-adhesion layer side to the weak adhesive layer, which can further increase the adhesion between the weak adhesive layer and the substrate and make it easier to suppress adhesive residue on the sensor processing film.

[0088] In step 4, the easily peelable adhesive layer formed in step 3 is bonded to the substrate-side surface of the substrate with a weak adhesive layer obtained in step 2. Step 4 results in a double-sided adhesive sheet having the easily peelable adhesive layer on one side of the substrate and the weak adhesive layer on the other side. Such a double-sided adhesive sheet has release sheets (a first release sheet and a second release sheet, respectively) on both sides.

[0089] In step 5, the first release sheet provided on the weak adhesive layer is peeled off, and then a sensor processing film is bonded to the exposed weak adhesive layer. In this case, the sensor processing film may not be formed with conductivity, or a conductive layer may be formed in advance. If the sensor processing film used in step 5 is not formed with conductivity, a conductive layer can be formed on the sensor processing film in step B described below. Also, if a conductive layer is formed in advance on the sensor processing film used in step 5, the conductive layer side is bonded to the weak adhesive layer. In this case, if a conductive layer is formed on the other side in step B described below, a double-sided conductive film (a film having sensors on both sides) can be formed.

[0090] 2. Laminate for Sensor Film Processing A sensor film can be produced using the laminate for sensor film processing of the present invention. The method for producing a sensor film using the laminate for sensor film processing is not particularly limited, and various methods can be used.

[0091] An example of producing a sensor film using the laminate for sensor film processing of the present invention will be described below with reference to FIG.

[0092] FIG. 2 is a schematic flow diagram showing an example of a method for producing a sensor film using a laminate for sensor film processing.

[0093] As shown in FIG. 2 , a method for manufacturing a sensor film using a laminate for processing a sensor film can include the steps of: Step A: bonding the surface of the laminate A on which the easily peelable adhesive layer 4 is located to a support 10 to form a laminate with a support; Step B: processing the processing film 1 of the laminate with a support to form a sensor 20 on the processing film; Step C: irradiating ultraviolet light from the support 10 side of the laminate with a support on which the sensor 20 has been formed, and then peeling the support 10 and the easily peelable adhesive layer 4 to obtain a laminate with a sensor film; and Step D: peeling the sensor film 1 from the laminate with a sensor film.

[0094] 2(a) is a schematic diagram showing the flow of step A. The support 10 used in step A is a member that serves as a base for fixing the laminate for processing a sensor film of the present invention.

[0095] The support is made of a material that transmits ultraviolet light, and examples thereof include glass plates and various resin plates.

[0096] By step A, a laminate with a support can be obtained.

[0097] As shown in FIG. 2( b), in step B, a sensor 20 is formed on the processing film 1. In step B, the method for forming the sensor 20 on the processing film (i.e., the sensor processing method) is not particularly limited, and for example, a wide variety of known methods can be used. An example of a method for forming the sensor is photolithography. A conductive layer is formed on the processing film 1 by photolithography, and the sensor can be obtained by performing a known etching process, such as alkaline etching, as necessary. It is also preferable that the sensor film processing laminate of the present invention has alkaline etching resistance. The method for imparting alkaline etching resistance is not particularly limited, and alkaline etching resistance can be imparted, for example, by adjusting the gel fraction.

[0098] In step C, as shown in Figure 2(c), ultraviolet (UV) rays are irradiated from the support 1 side (the back side of the support-attached laminate) of the support-attached laminate on which the sensor obtained in step B is formed. Thereafter, the support 10 and the easily peelable adhesive layer 4 of the laminate A are peeled off. This results in a laminate with a sensor film. The ultraviolet irradiation in step C reduces the adhesive strength of the easily peelable adhesive layer 4 in the laminate A, thereby reducing the adhesive strength between the support 10 and the easily peelable adhesive layer 4 and facilitating peeling.

[0099] The type of ultraviolet light to be irradiated in step C is not particularly limited. For example, ２ After the above steps, ultraviolet light may be irradiated.

[0100] Just to be clear, the laminate with sensor film obtained in step C is the laminate for sensor film processing of the present invention in which the processing film 1 is replaced with a sensor film. That is, the laminate with sensor film obtained in step C is a laminate in which a sensor film, a weak adhesive layer, a substrate, and an easily peelable adhesive layer are laminated in this order.

[0101] In step D, the sensor film is peeled off from the laminate with the sensor film. That is, the sensor film is peeled off from the weakly adhesive layer 2. In this way, the desired sensor film can be obtained.

[0102] In the method for producing a sensor film as described above, the sensor film is not peeled off immediately after sensor processing, but rather the entire laminate is first peeled off from the support, which makes it less likely to damage the sensor film than if the sensor film were peeled off first. When the entire laminate is peeled off from the support, the adhesive strength of the easy-peel adhesive layer is very low, allowing it to be peeled off with almost no bending, and the sensor film can then be peeled off while bending the laminate, making it particularly easy to suppress damage to the sensor film.

[0103] In specifying the inventions included in the present disclosure, the components (properties, structures, functions, etc.) described in each embodiment of the present disclosure may be combined in any manner. In other words, the present disclosure includes all subject matter consisting of all combinations of the components that can be combined as described in this specification.

[0104] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0105] Example 1 A laminate for processing a sensor film was manufactured according to the laminate configuration shown in Table 1. Specifically, an antistatic separator "50E-0010KF AS" manufactured by Fujimori Kogyo Co., Ltd. was prepared as the first release sheet, and a coating film was formed by applying a weak adhesive layer-forming adhesive to the surface of the first release sheet to a thickness of 15 μm after drying. The weak adhesive layer-forming adhesive was prepared by mixing 100 parts by mass (solids equivalent) of an acrylic adhesive ("AS-425" manufactured by Lion Specialty Chemicals Co., Ltd.) with 10 parts by mass of hexamethylene diisocyanate ("Crosslinker N" manufactured by Lion Specialty Chemicals Co., Ltd.) as a crosslinking agent. The coating film of the adhesive for forming the weak adhesive layer formed as described above was dried at 100°C for 90 seconds to form a weak adhesive layer, and the PVA easy adhesion layer side of "TA048#80" (Cosmoshine SRF (registered trademark)) manufactured by Toyobo Co., Ltd. was bonded to this weak adhesive layer as a substrate, and then cured at 40°C for 3 days to obtain a weak adhesive layer with a substrate.

[0106] On the other hand, an antistatic separator "50E-0010KF AS" manufactured by Fujimori Kogyo Co., Ltd. was prepared as a second release sheet, and an adhesive for forming an easily peelable adhesive layer was applied to the surface of this sheet so that the thickness after drying would be 20 μm to form a coating film. The adhesive for forming an easily peelable adhesive layer was prepared by mixing 100 parts by mass (solid content equivalent) of an acrylic polymer having a polymerizable double bond introduced therein ("ELX-6151YF" manufactured by Resonac Corporation), 0.8 parts by mass of tolylene diisocyanate ("Coronate L-55E" manufactured by Big Technos Corporation) as a crosslinking agent, and 1 part of "Omnirad 819" (manufactured by IGM Resins) as a photopolymerization initiator. The coating film of the adhesive for forming the easy-peel adhesive layer formed as described above was dried at 100°C for 90 seconds to form an easy-peel adhesive layer, and the substrate side surface (the easy-adhesion layer side for general hard coats) of the above-mentioned substrate-attached low-adhesion layer was then bonded to this easy-peel adhesive layer, followed by curing at 40°C for 3 days to obtain a double-sided adhesive sheet with a release sheet.

[0107] Next, the first release sheet of the double-sided adhesive sheet with release sheet obtained as described above was peeled off to expose the weak adhesive layer, and the surface of the PVA easy adhesion layer side of ``TA048#80'' (Cosmoshine SRF (registered trademark)) manufactured by Toyobo Co., Ltd. as a processing film was bonded to this weak adhesive layer to obtain a sensor film processing laminate with release sheet (processing film / weak adhesive layer / substrate / easy peel adhesive layer / second release sheet).

[0108] Example 2 As shown in Table 1, a release sheet-attached laminate for sensor film processing was obtained in the same manner as in Example 1, except that the adhesive for forming the easily peelable adhesive layer was changed to one prepared by mixing 100 parts by mass (solid content equivalent) of an acrylic polymer having a polymerizable double bond introduced therein ("ELX-6151YF" manufactured by Resonac Corporation), 0.5 parts by mass of tolylene diisocyanate ("Coronate L-55E" manufactured by Big Technos Corporation) as a crosslinking agent, and 0.5 parts by mass of "Omnirad 819" (manufactured by IGM Resins) as a photopolymerization initiator.

[0109] Example 3 As shown in Table 1, the adhesive for forming the easily peelable adhesive layer was changed to one prepared by mixing 100 parts by mass (solid content equivalent) of an acrylic polymer into which a polymerizable double bond had been introduced ("ELX-6520" manufactured by Resonac Corporation), 0.15 parts by mass of an epoxy-based thermal crosslinking agent ("CL-X50" manufactured by Resonac Corporation) as a crosslinking agent, and 2.5 parts by mass of "Omnirad 819" (manufactured by IGM Resins) as a photopolymerization initiator, and a release sheet-attached laminate for sensor film processing was obtained in the same manner as in Example 1 except that the drying temperature of the coating film of the adhesive for forming the easily peelable adhesive layer was changed to 130°C.

[0110] Example 4 As shown in Table 1, the adhesive for forming the easily peelable adhesive layer was changed to one prepared by mixing 100 parts by mass (solid content equivalent) of an acrylic polymer having a polymerizable double bond introduced therein ("ELX-6520" manufactured by Resonac Corporation), 0.1 parts by mass of an epoxy-based thermal crosslinking agent ("CL-X50" manufactured by Resonac Corporation) as a crosslinking agent, and 1 part by mass of "Omnirad 819" (manufactured by IGM Resins) as a photopolymerization initiator, and a release sheet-attached laminate for sensor film processing was obtained in the same manner as in Example 3, except that the substrate was changed to "TA048#60" (Cosmoshine SRF (registered trademark) manufactured by Toyobo Co., Ltd.).

[0111] (Example 5) As shown in Table 1, the adhesive for forming the easy-peel adhesive layer was changed to a mixture of 100 parts by mass (solid content equivalent) of an acrylic polymer into which a polymerizable double bond had been introduced ("ELX-6151YF" manufactured by Resonac Co., Ltd.), 1.8 parts by mass of tolylene diisocyanate ("Coronate L-55E" manufactured by Big Technos Co., Ltd.) as a crosslinking agent, and 1 part by mass of "Omnirad 819" (manufactured by IGM Resins Co., Ltd.) as a photopolymerization initiator. In addition, a laminate for sensor film processing with a release sheet was obtained in the same manner as in Example 1, except that the weak adhesive layer was attached to the surface of the substrate coated with an easy-adhesion layer for general HC (hard coat).

[0112] (Example 6) A sensor film processing laminate with a release sheet was obtained in the same manner as in Example 1, except that the weak adhesive layer was attached to the surface coated with the general HC easy adhesion layer of "TA048 # 80" (Cosmoshine SRF (registered trademark)) manufactured by Toyobo Co., Ltd. as a processing film.

[0113] Example 7 A release sheet-attached laminate for sensor film processing was obtained in the same manner as in Example 1, except that the substrate was changed to "U483#50 (double-sided easy-adhesive PET)" manufactured by Toray Industries, Inc.

[0114] Example 8 A release sheet-attached laminate for sensor film processing was obtained in the same manner as in Example 1, except that the substrate was changed to "A4360#100 (double-sided easy-adhesion PET)" manufactured by Toyobo Co., Ltd.

[0115] Example 9 A release sheet-attached laminate for sensor film processing was obtained in the same manner as in Example 7, except that the processing film was changed to "U483#50 (double-sided easy-adhesive PET)" manufactured by Toray Industries, Inc.

[0116] Example 10 A release sheet-attached laminate for sensor film processing was obtained in the same manner as in Example 7, except that the adhesive for forming the easily peelable adhesive layer was changed to one prepared by mixing 100 parts by mass (solid content equivalent) of an acrylic polymer into which a polymerizable double bond had been introduced ("ELX-6520" manufactured by Resonac Corporation), 0.9 parts by mass of an epoxy-based thermal crosslinking agent ("CL-X50" manufactured by Resonac Corporation) as a crosslinking agent, and 2.5 parts by mass of "Omnirad 819" (manufactured by IGM Resins) as a photopolymerization initiator.

[0117] Example 11 A release sheet-attached laminate for sensor film processing was obtained in the same manner as in Example 7, except that the processing film was changed to a COP film "ZF16" manufactured by Zeon Corporation.

[0118] Comparative Example 1 A release sheet-attached laminate for sensor film processing was obtained in the same manner as in Example 1, except that the adhesive for forming the easily peelable adhesive layer was changed to one prepared by mixing 100 parts by mass (solid content equivalent) of an acrylic polymer into which a polymerizable double bond had been introduced ("ELX-6151YF" manufactured by Resonac Corporation), 3 parts by mass of tolylene diisocyanate ("Coronate L-55E" manufactured by Big Technos Corporation) as a crosslinking agent, and 1 part by mass of "Omnirad 819" (manufactured by IGM Resins) as a photopolymerization initiator.

[0119] Comparative Example 2 A laminate for processing a sensor film with a release sheet was obtained in the same manner as in Example 1, except that the adhesive for forming the weak adhesive layer was changed to one prepared by mixing 100 parts by mass (solid content equivalent) of an acrylic adhesive ("AS-425" manufactured by Lion Specialty Chemicals Co., Ltd.) and 3 parts by mass of hexamethylene diisocyanate ("Crosslinker N" manufactured by Lion Specialty Chemicals Co., Ltd.) as a crosslinking agent.

[0120] (Comparative Example 3) A laminate for sensor film processing with a release sheet was obtained in the same manner as in Example 7, except that the adhesive for forming the weak adhesive layer and the adhesive for forming the easily peelable adhesive layer were changed to one prepared by mixing 100 parts by mass (solid content equivalent) of an acrylic polymer into which a polymerizable double bond had been introduced ("ELX-6151YF" manufactured by Resonac Corporation), 0.8 parts by mass of tolylene diisocyanate ("Coronate L-55E" manufactured by Big Technos Corporation) as a crosslinking agent, and 1 part by mass of "Omnirad 819" (manufactured by IGM Resins) as a photopolymerization initiator.

[0121] Evaluation Method (Storage Modulus and Tan δ) The storage modulus of the weak adhesive layer or the easily peelable adhesive layer was measured using Rheogel-E4000 manufactured by UBM Co., Ltd. by a solid shear method under conditions of a temperature rise rate of 2°C / min, a frequency of 1 Hz, and a temperature range of 0°C to 110°C, and the storage modulus at 25°C and 100°C was read.

[0122] (Gel Fraction) The slightly adhesive layer with substrate obtained in the process of producing the pressure-sensitive adhesive sheets of the Examples and Comparative Examples was cut into 5 cm squares, and the weight W0 was measured after peeling off the first release sheet. 50 ml of ethyl acetate was then added and the mixture was shaken for 24 hours. After that, the deposits on the substrate surface were scraped off into a sample bottle, and the substrate was removed. The contents of the sample bottle were filtered through a 150-mesh stainless steel wire mesh. The residue on the wire mesh and the substrate were dried at 100°C for 1 hour, and the gel dry weight W1 (g) and the substrate dry weight W2 (g) were measured, respectively. The value calculated from the obtained dry weight using the following formula: gel fraction (%) = (W1 / (W0-W2)) x 100 was taken as the gel fraction of the slightly adhesive layer.

[0123] (Adhesion to Glass) <Measurement 1 of Adhesion to Glass> The laminates for sensor film processing with release sheets obtained in Examples and Comparative Examples were cut to a width of 25 mm, and the film for sensor processing was peeled off to expose the weak adhesive layer. 24 hours had passed since the weak adhesive layer was attached to soda glass with a pressure of 2 kg. The test specimens were then treated at 100°C for 1 hour and then at 130°C for 5 minutes, and then measured with a UV LED (365 nm) at 180 mW for 800 mJ / cm. ２ The laminate including the weak adhesive layer, the substrate, and the easily peelable adhesive layer was then peeled off at an angle of 180° at a peeling speed of 300 mm / min, to measure the adhesive strength of the weak adhesive layer, which was defined as the adhesive strength of the weak adhesive layer to glass.

[0124] <Measurement of adhesive strength to glass 2> The laminates for sensor film processing with release sheet obtained in the Examples and Comparative Examples were cut to a width of 25 mm, and the second release sheet was peeled off to expose the easily peelable adhesive layer of the laminate. 24 hours had passed since the easily peelable adhesive layer was attached to soda glass with a pressure of 2 kg. The test specimens were then treated at 100°C for 1 hour and then at 130°C for 5 minutes, and then measured with a UV LED (365 nm) at 180 mW for 800 mJ / cm. ２The laminate in the test piece was then peeled from the soda glass at an angle of 180° at a peeling speed of 300 mm / min (i.e., the easily peelable adhesive layer of the laminate was peeled from the soda glass at an angle of 180° at a peeling speed of 300 mm / min), and the adhesive strength at this time was measured and defined as the adhesive strength of the easily peelable adhesive layer to glass.

[0125] <Initial adhesive strength to glass; easily peelable adhesive layer> The release sheet-attached sensor film processing laminates obtained in the Examples and Comparative Examples were cut to a width of 25 mm, and the second release sheet was peeled off to expose the easily peelable adhesive layer of the laminate. The easily peelable adhesive layer was attached to soda glass with a pressure of 2 kg, and a test specimen was obtained 24 hours later. The laminate was then peeled off from the soda glass at a peeling speed of 300 mm / min at an angle of 180° (i.e., the easily peelable adhesive layer of the laminate was peeled off from the soda glass at a peeling speed of 300 mm / min at an angle of 180°), and the adhesive strength at this time was measured, and this was defined as the initial adhesive strength of the easily peelable adhesive layer to glass.

[0126] (Presence or absence of lifting from the glass surface and presence or absence of curling) Presence or absence of lifting (peeling) from the glass surface The release sheet-attached sensor film processing laminate obtained in the Examples and Comparative Examples was cut to a width of 25 mm, and the second release sheet was peeled off to expose the easily peelable adhesive layer, which was then attached to a glass slide ("S9112" from Matsunami Glass Industry Co., Ltd.) with a pressure of 2 kg to obtain a laminate with a glass slide. After 24 hours, this laminate with a glass slide was treated at 100°C for 1 hour, 130°C for 5 minutes, immersed in a 3% by mass aqueous solution of sodium hydroxide at 40°C for 3 minutes, washed with water, and air-dried in this order to perform pseudo-sensor processing. During this pseudo-sensor processing, the laminate was visually inspected for spontaneous peeling (peel) from the glass slide surface. Peeling was evaluated as "present" and no peeling was evaluated as "absent," and the presence or absence of lifting during sensor processing was evaluated.

[0127] After the pseudo sensor processing was completed, 800 mJ / cm at 180 mW ２The slide glass side was irradiated with ultraviolet light (365 nm, UV LED). After this, it was visually confirmed whether the laminate naturally peeled off from the slide glass surface (whether there was any lifting), and the presence or absence of lifting after UV irradiation was evaluated by rating it as "present" if peeling occurred and "absent" if no peeling occurred.

[0128] Presence or absence of curling After irradiating with ultraviolet light as described above, the laminate was peeled from the glass slide, and the lift distances (mm) of the four corners of the peeled laminate were measured. The average value was calculated to evaluate the presence or absence of curling after UV irradiation. Next, the sensor processing film (sensor film) was peeled from the laminate, and the lift distances (mm) of the four corners of this sensor processing film were measured. The average value was calculated to evaluate the presence or absence of curling of the sensor processing film. Note that with the sensor processing surface facing up, a state in which the corner is X mm higher than the center was expressed as "+X mm," and a state in which the corner is X mm lower than the center was expressed as "-X mm." Therefore, ±0 means that no curling occurred.

[0129] (Presence or absence of adhesive residue) In the evaluation of the presence or absence of curl described above, when the laminate was peeled from the slide glass, adhesive residue on the slide glass surface was visually observed, and if adhesive residue was observed, it was marked as "present", and if no adhesive residue was observed, it was marked as "absent". Next, the sensor processing film was peeled from the peeled laminate, and adhesive residue on the sensor processing film surface was visually observed, and if adhesive residue was observed, it was marked as "present", and if no adhesive residue was observed, it was marked as "absent".

[0130] (Evaluation Results) Table 1 shows the structure of the laminate for processing a sensor film, the physical properties of the weak adhesive layer and the easily peelable adhesive layer in the laminate, and the evaluation results for the presence or absence of lifting from the glass surface and the presence or absence of curling.

[0131] As can be seen from Table 1, the laminate for sensor film processing obtained in the examples suppressed adhesive residue on the sensor film, was less likely to lift during and after sensor processing, and furthermore, curling of the laminate and the film for sensor processing was suppressed.

[0132]

[0133] A: Laminate 1: Sensor processing film 2: Slightly adhesive layer 3: Substrate 4: Easily peelable adhesive layer 5: Release sheet

Claims

1. A laminate in which a weak adhesive layer, a substrate, and an easily peelable adhesive layer are laminated in this order, the weak adhesive layer does not have ultraviolet curing properties, and has an adhesive strength to glass of 2 N / 25 mm or less as measured in the following Glass Adhesion Strength Measurement 1, the easily peelable adhesive layer has a property of decreasing adhesive strength by irradiation with ultraviolet light, and the easily peelable adhesive layer has an initial adhesive strength to glass of 5 N / 25 mm or more, and has an adhesive strength to glass of 1 N / 25 mm or less as measured in the following Glass Adhesion Strength Measurement 2. <Glass Adhesion Strength Measurement 1> A test specimen in which the weak adhesive layer was attached to soda glass with a pressure of 2 kg for 24 hours was subjected to a heat treatment at 100°C for 1 hour and a heat treatment at 130°C for 5 minutes in this order, and then a UV LED (365 nm) was used to measure 800 mJ / cm at 180 mW. ２ The soda glass side is irradiated with ultraviolet light of 100 nm. Thereafter, the adhesive strength of the weak adhesive layer is measured when peeled off at 180° at a peeling speed of 300 mm / min to obtain the value of adhesive strength to glass. <Measurement of adhesive strength to glass 2> A test specimen 24 hours after the easy-peel adhesive layer of the laminate was attached to the soda glass with a pressure of 2 kg was subjected to a heat treatment at 100° C. for 1 hour and a heat treatment at 130° C. for 5 minutes in this order, and then a UV LED (365 nm) was used to irradiate the test specimen with 800 mJ / cm at 180 mW. ２ The laminate included in the test specimen is then peeled off from the soda glass at an angle of 180° at a peeling speed of 300 mm / min, and the adhesive strength is measured to obtain the adhesive strength of the easily peelable adhesive layer to glass.

2. A laminate for film processing comprising the laminate according to claim 1, which is used for film processing, and further comprises a processing film on the surface of the low-adhesive layer opposite the substrate.

3. The laminate for film processing according to claim 2, wherein the processing film is a film for sensor processing, and the film processing is sensor processing.

4. The laminate for film processing according to claim 3, wherein the sensor processing film is an ultraviolet ray blocking film that blocks 90% or more of ultraviolet rays with a wavelength of 370 nm.

5. A laminate for film processing according to claim 3 or 4, wherein the main component contained in the film for sensor processing is the same as the main component contained in the substrate.

6. A laminate for film processing according to claim 3 or 4, wherein a release sheet is attached to the surface of the easily peelable adhesive layer opposite the substrate.

7. A method for producing a sensor film using the laminate for film processing described in claim 3 or 4, comprising: step A of bonding the surface of the laminate with the easily peelable adhesive layer to a support to form a laminate with a support; step B of processing the film for processing of the laminate with the support to form a sensor on the film for processing; step C of irradiating ultraviolet light from the support side of the laminate with the support on which the sensor is formed, and then peeling the support and the easily peelable adhesive layer to obtain a laminate with a sensor film; and step D of peeling the sensor film from the laminate with the sensor film.

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