JP5203072B2 - Upper electrode for touch panel - Google Patents

Description

  The present invention relates to an upper electrode for a touch panel. Specifically, it is a double-sided PSA sheet that has an adhesive layer with excellent adhesion, re-peelability, pen sliding durability, etc., and excellent heat-resistant water adhesion between the adhesive layer and the substrate film, and is hard coated. The present invention relates to an upper electrode for a touch panel in which a laminate in which layers are laminated and a conductive laminate are bonded together.

  The touch panel is recognized as an excellent input method, and is used in various fields such as bank ATMs, ticket vending machines, personal digital assistants, game machines, car navigation systems, and the like. A transparent electrode is required for a touch panel, and glass has conventionally been used for a substrate. Recently, however, many transparent conductive films having a transparent conductive layer provided on a plastic film surface have been proposed.

  For example, when used as an upper electrode, the transparent conductive film requires a conductive layer to be an electrode, a base material that supports the conductive layer, and a hard coat layer that can withstand friction when inputting by hand or a dedicated pen. It is. For example, Patent Document 1 discloses a transparent conductive film in which a plastic film, a cured product layer, and a transparent conductive thin film are laminated. In this document, a transparent film and a film serving as an input surface (hard coat layer) are disclosed. A conductive film is bonded through an adhesive and used as an electrode for a touch panel. Patent Document 2 discloses a laminate in which a plastic film provided with a hard coat layer and a transparent conductive film having a transparent conductive thin film are bonded together via a transparent adhesive layer.

  Thus, when each layer required as an electrode for touch panels is laminated, an adhesive layer is often required. Since many members for touch panels are expensive, an adhesive layer excellent in removability that can be peeled off when a sticking mistake occurs during bonding and fixing with the adhesive layer and can be attached again is desirable. It is also known that if a pressure-sensitive adhesive layer with cushioning properties is used, durability against repeated pressing (pen sliding durability) on the touch panel is improved.

  For these reasons, it is conceivable to use silicone rubber as an adhesive for touch panel members. In particular, when a double-sided pressure-sensitive adhesive sheet having a silicone rubber pressure-sensitive adhesive layer is used, a plastic film having a hard coat layer and a transparent conductive film having a transparent conductive thin film can be easily bonded. However, it cannot be said that silicone rubber and a plastic film substrate such as polyethylene terephthalate have sufficient adhesion. If the adhesiveness between the adhesive layer and the film base material is inferior, there is a problem in that peeling occurs at the joining portion, and electricity is not supplied even when touched. Further, when the touch panel is used for car navigation or the like, the environment inside the vehicle may be considerably hot and humid, but it is necessary to withstand such severe use conditions.

  On the other hand, the present inventors have proposed a rubber film composite in which a rubber layer is directly bonded to a polyester film as a base material without using an adhesive in Patent Documents 3 to 5 and the like, and a manufacturing method thereof. In these techniques, it is described that it is preferable to use a film subjected to easy adhesion treatment as a polyester film. However, the rubber film composite obtained by the above method is inferior in the durability of adhesion between the polyester film and the silicone rubber layer, and when used under the above severe conditions, the polyester film and the silicone rubber layer are There was a problem that it might peel off.

Further, the double-sided pressure-sensitive adhesive sheet is usually shipped in a form in which a separate film is laminated on the surface of the pressure-sensitive adhesive layer in order to improve the handleability, and is used by peeling the separate film and sticking it to the target article when actually used. However, there is a strong demand for reducing the peeling force depending on the application. However, if the peel strength of the separate film is too small, when the sheet is wound in the production process of the adhesive sheet, partial separation of the separate film occurs, and an air layer enters in a direction perpendicular to the sheet winding direction. The so-called channeling phenomenon may occur.
JP 2007-59360 A JP 2007-234424 A JP 10-53659 A Japanese Patent Laid-Open No. 10-58605 Japanese Patent Laid-Open No. 10-95071

  In the present invention, in view of the above circumstances, a double-sided pressure-sensitive adhesive sheet having a cushioning pressure-sensitive adhesive layer and excellent in adhesiveness between the pressure-sensitive adhesive layer and the base film, particularly excellent in heat-resistant water adhesion, was found. An object is to provide an upper electrode for a touch panel having a structure in which a laminate having a layer and a conductive laminate are bonded together.

  The upper electrode for a touch panel of the present invention that has solved the above problems includes a laminate (1) having a configuration in which a hard coat layer is laminated on a transparent substrate, and a conductive laminate in which a transparent conductive layer is laminated on a transparent substrate ( 2) has a silicone rubber adhesive layer on at least one side of the polyester base film, and the silicone rubber adhesive layer is a polyester base when the hot water adhesion is evaluated by the method defined in the specification. It is characterized by being bonded with a double-sided PSA sheet that does not peel from the film.

  In the double-sided pressure-sensitive adhesive sheet, an adhesion improving layer is provided between the polyester base film and the silicone pressure-sensitive adhesive layer, and the thickness of the adhesion improving layer is 0.01 to 0.5 μm and is crosslinked. The adhesive improvement layer contains a reaction product of at least one polymer selected from the group consisting of polyester, polyurethane and acrylic polymer and a crosslinking agent. It is a preferred embodiment of the invention. Further, the adhesion improving layer may include a self-crosslinked one or more types of self-crosslinked polymers selected from the group consisting of self-crosslinked polyester, polyurethane and acrylic polymers.

  The silicone rubber pressure-sensitive adhesive layer preferably contains a crosslinked silicone compound having a polydimethylsiloxane skeleton, and the crosslinked silicone compound has a polydimethylsiloxane skeleton having a number average molecular weight of 50,000 to 500,000. It is preferable that the uncrosslinked product is crosslinked.

  The double-sided pressure-sensitive adhesive sheet may have a silicone rubber pressure-sensitive adhesive layer and an acrylic pressure-sensitive adhesive layer, or both sides may be a silicone rubber pressure-sensitive adhesive layer.

  The double-sided pressure-sensitive adhesive sheet has a separate film laminated on the surface of the silicone rubber pressure-sensitive adhesive layer before use. After the separation film is peeled off, the laminate (1) and the conductive laminate (2) are pasted. Preferably, the peel strength between the separate film and the silicone rubber adhesive layer measured by the method defined in the specification is 0.03 to 1.0 N / 20 mm. Preferably there is. The release layer of the separate film is preferably a layer containing a binder resin, a polymer wax component and an antistatic agent.

  In the upper electrode for a touch panel of the present invention, a double-sided pressure-sensitive adhesive sheet having a silicone rubber pressure-sensitive adhesive layer having both sticking property and removability is used. The sheet can be removed and re-applied. In addition, since the silicone rubber pressure-sensitive adhesive layer has good elasticity, the touch panel can be given good cushioning properties, so that the pen sliding durability of the touch panel can be improved.

  Furthermore, the double-sided pressure-sensitive adhesive sheet used for the upper electrode for a touch panel of the present invention has excellent adhesion durability between the pressure-sensitive adhesive layer and the base polyester film, and is suitable even when used under harsh conditions. Can be used. In addition, the peeling force between the separate film and the silicone rubber pressure-sensitive adhesive layer laminated before use of the double-sided pressure-sensitive adhesive sheet is controlled to an appropriate range, and in the process of winding the double-sided pressure-sensitive adhesive sheet, the above-mentioned channeling phenomenon Since generation | occurrence | production is suppressed, a high quality double-sided adhesive sheet can be produced stably. Moreover, the workability | operativity at the time of incorporating a double-sided adhesive sheet in the upper electrode for touchscreens is also excellent.

  Therefore, a high-performance touch panel can be provided by using the upper electrode for a touch panel of the present invention.

  The upper electrode for a touch panel of the present invention includes a laminate (1) having a configuration in which a hard coat layer is laminated on a transparent substrate, and a conductive laminate (2) in which a transparent conductive layer is laminated on a transparent substrate. The silicone rubber adhesive layer has a silicone rubber adhesive layer on at least one surface of the polyester base film, and the silicone rubber adhesive layer has a polyester base when evaluated for heat resistant water adhesion (details will be described later) by the method defined in the specification. It is characterized in that it is bonded with a double-sided PSA sheet that does not peel from the material film. First, each constituent material of the double-sided pressure-sensitive adhesive sheet will be described.

[Polyester base film]
As the polyester base film of the double-sided pressure-sensitive adhesive sheet, any polyester film having polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate or the like as a main component (80% by mass or more) can be used. A biaxially stretched one is desirably used. The production method of the biaxially stretched polyester film is not particularly limited. For example, after drying the polyester as necessary, it is supplied to a known melt extruder, extruded from a slit-shaped die into a sheet, electrostatic application, etc. In this manner, the unstretched sheet may be stretched after being brought into close contact with the casting drum, cooled and solidified to obtain an unstretched sheet. The biaxial stretching method may be either simultaneous biaxial stretching or sequential biaxial stretching. Although the thickness of a base film is not specifically limited, About 10-300 micrometers is preferable, More preferably, it is 70-260 micrometers. If the thickness of the film is less than 10 μm, the mechanical strength is insufficient and handling becomes difficult. On the other hand, when the thickness exceeds 300 μm, the thickness becomes too thick when used for a touch panel member, and thus is not suitable for a mobile device or the like.

  The polyester base film may be subjected to a known surface treatment such as a corona treatment, a flame treatment, or a plasma treatment. Adhesion with the pressure-sensitive adhesive layer (or an adhesion improving layer described later) is improved.

[Adhesive layer]
The double-sided pressure-sensitive adhesive sheet used in the present invention has a silicone rubber pressure-sensitive adhesive layer (hereinafter sometimes referred to as a first pressure-sensitive adhesive layer). Silicone rubber is excellent in elasticity and can impart cushioning properties to the touch panel.

  The silicone rubber is not particularly limited, but preferably contains a crosslinked silicone compound having a polydimethylsiloxane skeleton as a main component (70% by mass or more, more preferably 90% by mass or more, and further preferably 100% by mass). . In particular, the crosslinked silicone compound having a polydimethylsiloxane skeleton is preferably obtained by crosslinking an uncrosslinked product having a number average molecular weight (Mn) of 50,000 to 500,000. The uncrosslinked Mn is more preferably 80,000 to 400,000, and more preferably 100,000 to 350,000.

  By using an uncrosslinked product of a silicone compound, solubility in a solvent and fluidity can be secured, and formation of an adhesive layer is facilitated. Moreover, since Mn of 50,000 or more of an uncrosslinked body improves crosslinkability, it is suitable. When the Mn of the uncrosslinked product is 500,000 or less, deterioration in operability during production such as the viscosity of the coating solution becoming too high can be suppressed. Therefore, it is a preferred embodiment that an uncrosslinked layer of silicone compound is formed and then crosslinked.

  The raw material of conventionally known silicone rubber is a millable type silicone rubber compound, but such a compound has a lower solubility in a solvent depending on the storage state, and is not dissolved when a silicone rubber layer is applied. The appearance quality may deteriorate depending on the object. In addition, a coating solution in which a silicone rubber compound is dissolved in a solvent has a problem that the gelation of the solution occurs depending on the storage state and cannot be used as a coating solution. By using the above-mentioned uncrosslinked silicone compound, it is superior in quality, quality stability, operability during production, and the like as compared with a case where a conventionally known millable type silicone compound is used as a raw material.

  As an uncrosslinked silicone compound satisfying the above contents, for example, a commercially available silicone oil can be used. When silicone oil is used, non-reactive dimethyl silicone oil is preferably used among straight silicone oils. Thereby, the silicone compound after crosslinking has a polydimethylsiloxane skeleton. The methyl phenyl type silicone oil has poor crosslinkability, and the reactive methyl hydrogen type silicone oil has poor storage stability, which may adversely affect the quality and operability. If it is less than (more preferably less than 5 mass%), you may mix | blend and use the silicone compound which does not have polydimethylsiloxane frame | skeleton, such as a methylphenyl type, a methyl hydrogen type, or various modified types.

  The uncrosslinked silicone compound may contain a polyalkylalkenylsiloxane skeleton silicone compound as long as it is less than 10% by mass. Most preferably, it consists only of a polydimethylsiloxane skeleton silicone compound that does not contain a polyalkylalkenylsiloxane skeleton silicone compound.

  The adhesive layer in the present invention may contain a reinforcing agent such as silica as long as the effect of the present invention is not hindered, but it is particularly preferable that no reinforcing agent is contained.

  Even if the said adhesion layer contains the adhesive improvement agent for raising the adhesive strength of an adhesion layer and a polyester-type base film (or adhesive improvement layer mentioned later), and making it difficult to peel an adhesion layer. Good. As the adhesion improver, it is preferable to use a compound containing a reactive group active against radical reaction. Examples of this compound include (meth) acrylic acid derivatives and allyl derivatives. Among them, derivatives having 2 or more, particularly 3 or more unsaturated bonds are preferred. These compounds are widely used as rubber co-crosslinking agents, and examples include esters of polyhydric alcohol and (meth) acrylic acid, allyl esters of polycarboxylic acid, triallyl isocyanurate, triallyl cyanurate, and the like. .

  The ester of the polyhydric alcohol and (meth) acrylic acid is an ester compound obtained by esterifying two or more alcoholic hydroxyl groups of a polyhydric alcohol having two or more alcoholic hydroxyl groups with (meth) acrylic acid. Specifically, for example, ethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, Neopentyl glycol di (meth) acrylate, 2,2'-bis [4- (meth) acryloxydiethoxyphenyl] propane, glycerol di (meth) acrylate, glycerol tri (meth) acrylate, trimethylolpropane tri (meth) Acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, tetramethylolmethane di (meth) acrylate, tetramethylolmethanetri (meth) acrylate, Tiger methylol tetra (meth) acrylate, dimer diol di (meth) acrylate and the like, particularly compounds containing three or more (meth) acryloyl group is preferred. In addition, although said compound illustrated each single ester compound of acrylic acid and methacrylic acid, the form of mixed ester of acrylic acid and methacrylic acid may be sufficient.

  Examples of the allyl ester of polyvalent carboxylic acid include phthalic acid diarylate, trimellitic acid diarylate, and pyromellitic acid tetraarylate.

  Any one of the above-mentioned adhesiveness improving agents may be used alone, or two or more thereof may be used in combination. In addition, the adhesive improvement agent used for this invention is not limited to said exemplary compound.

  0.2-20 mass parts is preferable with respect to 100 mass parts of silicone compound components, and, as for the compounding quantity of the said adhesive improvement agent, 0.5-10 mass parts is more preferable. By making the compounding amount of the adhesion improver 0.2 parts by mass or more, the effect of improving the hot water adhesion of the pressure-sensitive adhesive layer is further increased. On the other hand, when the compounding amount of the adhesion improver exceeds 20 parts by mass, the effect of improving the hot water adhesiveness not only reaches saturation, but conversely, this effect may be deteriorated.

  The lower limit of the thickness of the adhesive layer is preferably 3 μm, more preferably 5 μm, and even more preferably 8 μm from the viewpoint of adhesive strength. On the other hand, the upper limit of the thickness of the pressure-sensitive adhesive layer may be determined within a range where the pressure-sensitive adhesive force can be stably maintained from the viewpoint of economy. For example, 100 μm is preferable, 80 μm is more preferable, and 50 μm is further preferable.

  In the present invention, the method for forming the adhesive layer is not limited, but the above-mentioned uncrosslinked silicone compound is dissolved or dispersed in a solvent, and if necessary, an adhesion improver is added to prepare a coating solution. In a preferred embodiment, the film is formed by a crosslinking treatment after coating by a coating method.

  For example, uncrosslinked silicone oil dissolves well in aromatic hydrocarbons such as toluene. Therefore, it is preferable to dissolve in these solvents and apply by a coating method. When an uncrosslinked silicone oil is used, a compound plasticizing step by kneading or the like necessary for dissolving a conventional millable type silicone rubber compound in a solvent is unnecessary. In addition, the obtained coating solution has good storage stability, and does not cause a thickening phenomenon such as gelation, which is often seen when preparing a solution of a silicone rubber compound. Furthermore, since the production | generation of the foreign material by the silicone rubber compound not melt | dissolving which may generate | occur | produce in the solutionization of a silicone rubber compound is suppressed, there exists a merit that a coating liquid with high clarity is obtained.

  For example, the pressure-sensitive adhesive layer is formed by applying a coating liquid containing the silicone oil or the like onto the surface of a polyester base film (or an adhesion improving layer formed on the surface thereof) or the surface of a release layer of a separate film described later. It can be formed by coating, laminating other layers, or performing a crosslinking treatment without laminating.

  The crosslinking method of the silicone compound may be, for example, thermal crosslinking, or may be crosslinking with high energy active rays such as electron beams and γ rays. It is considered that when an active ray is irradiated on a silicone compound, hydrogen is extracted from the methyl group of polydimethylsiloxane, and a crosslinking reaction occurs between adjacent silicone compounds from which hydrogen is extracted from the methyl group. Therefore, in the crosslinking method using actinic radiation, it is not necessary to add an additive such as a peroxide for radical generation or a crosslinking catalyst to the silicone compound. For this reason, the contamination of the adherend due to the residue of these additives is suppressed, and it is not necessary to consider the pot life after blending the crosslinking catalyst, etc., so that the crosslinking is completed efficiently in a short time. There are merits such as higher.

  Among the actinic rays, the electron beam cross-linking method is preferable because of the availability of an irradiation device (EB irradiation device). As an electron beam irradiation amount in an EB irradiation apparatus, the range of 5-50 Mrad is preferable. By setting the electron beam irradiation amount to 5 Mrad or more, the crosslinking reaction of the silicone compound can be promoted, and the adhesive residue on the adherend can be reduced and the repairability can be improved when re-peeling. On the other hand, by setting the electron beam irradiation amount to 50 Mrad or less, it is possible to suppress a decrease in adhesiveness due to excessive progress of the crosslinking reaction.

  From the viewpoint of reliability when using the upper electrode for a touch panel, the lower limit of the adhesive strength of the adhesive layer is preferably 0.01 N / 20 mm (180 ° peel test against glass, pulling speed 300 mm / min), more preferably. 0.05 N / 20 mm. On the other hand, the upper limit of the adhesive strength of the adhesive layer is preferably 1.0 N / 20 mm, more preferably 0.5 N / 20 mm, from the viewpoint of improving removability and ensuring good repairability. Moreover, it is preferable from the point of repair property that the adhesion layer does not remain on the glass surface when evaluated by the above evaluation method, that is, there is no adhesive residue.

  In this invention, it is preferable that the said adhesion layer has adhere | attached firmly on the polyester-type base film. For example, when a cutter knife is inserted between the pressure-sensitive adhesive layer and the polyester-based substrate film and peeled off by applying a force with a finger (exposing the interface), it is preferable that the adhesive strength is strong and the interface cannot be applied. . In the present invention, as described later, it is desirable to provide an adhesion improving layer between the pressure-sensitive adhesive layer and the polyester base film, but since the thickness of the adhesion improving layer is thin, the true interface in the above-mentioned interface Cannot be analyzed and is not clear. In short, it is preferable that the pressure-sensitive adhesive layer and the polyester-based substrate film are firmly bonded and the interface cannot be formed. Hereinafter, in the present invention, the above characteristic may be simply referred to as adhesiveness.

  Moreover, it is preferable that the said adhesiveness is maintained even if the double-sided adhesive sheet used by this invention is preserve | saved for a long time in hot water. Hereinafter, the adhesive hot water durability is referred to as heat resistant water adhesive.

[Heat resistant water adhesion]
Here, a method for evaluating the heat-resistant water adhesion, which is an important effect of the double-sided PSA sheet used in the present invention, will be described.

  When measuring the hot water adhesiveness of the silicone rubber pressure-sensitive adhesive layer, the double-sided pressure-sensitive adhesive sheet is cut into 50 mm × 50 mm, and a separate film (described later) is peeled off. The sample is submerged in a 500 cc cylindrical glass container with 400 cc of distilled water so that the silicone rubber adhesive layer is on the bottom, and the container is covered with the entire sample immersed in water. do. In the case where the sample is not immersed in water by its own weight, for example, a polyester film having a size of 60 mm × 60 mm and a thickness of 188 μm may be placed on the sample and weighted. The size and material of the weight are not particularly limited, and the entire sample may be immersed in water. The container containing the sample is placed in a gear oven set at 80 ° C. and allowed to stand for 24 hours. After heat treatment, remove the container from the oven, quickly remove the sample, apply force with the finger pad from the adhesive layer side to the end and rub it 10 times, and evaluate whether the adhesive layer peels from the polyester base film side In addition, the case where the pressure-sensitive adhesive layer does not peel is indicated by ○, and the case where the pressure-sensitive adhesive layer peels is indicated by ×.

  By selecting a double-sided pressure-sensitive adhesive sheet that does not peel off the pressure-sensitive adhesive layer in this hot water adhesiveness, when the upper electrode for a touch panel of the present invention is used as a touch panel upper electrode for a car navigation system, Therefore, the reliability of the apparatus is improved.

  In order to prevent the pressure-sensitive adhesive layer from peeling off in the hot water-resistant adhesiveness, it is desirable to provide an adhesion improving layer between the polyester base film and the silicone rubber pressure-sensitive adhesive layer. Therefore, the adhesion improving layer will be described next.

[Adhesion improvement layer]
In the double-sided pressure-sensitive adhesive sheet used for the upper electrode for a touch panel of the present invention, it is preferable to provide an adhesion improving layer between the polyester base film and the silicone rubber pressure-sensitive adhesive layer. The thickness of the adhesion improving layer is preferably 0.01 to 0.5 μm. If the thickness of the adhesion improving layer is 0.01 to 0.5 μm, good hot water-resistant adhesiveness is exhibited. However, if the thickness is outside the above range, the hot water-resistant adhesive property may not be good, which is not preferable. A more preferable thickness range is 0.03 to 0.4 μm, and 0.05 to 0.3 μm is even more preferable.

  A cross-linked polymer layer (cross-linked polymer layer) is preferable as the adhesion improving layer, and there are cases where the polymer is a layer cross-linked with a cross-linking agent and a layer using a self-cross-linking polymer.

  The polymer that can be used in the method of crosslinking with a crosslinking agent is not particularly limited, but is preferably at least one selected from the group consisting of polyesters, polyurethanes, and acrylic polymers. The above polymers may be used alone or in combination of two or three different types.

[Polyester for adhesive improvement layer]
The polyester has an ester bond in the main chain or side chain, and is obtained by polycondensation of polyvalent carboxylic acid and glycol.

  As the polyvalent carboxylic acid component constituting the polyester, aromatic, aliphatic, and alicyclic dicarboxylic acids, trivalent or higher polyvalent carboxylic acids, and ester derivatives thereof can be used.

  Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bisphenoxy Ethane-p, p′-dicarboxylic acid, phenylindanedicarboxylic acid and the like can be used. From the viewpoint of the strength and heat resistance of the adhesion improving layer, these aromatic dicarboxylic acids are preferably 30 mol% or more, more preferably 35 mol% or more, more preferably 40 mol in 100 mol% of the polyvalent carboxylic acid component. It is preferable to use polyester occupying at least%.

  Examples of the aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and the like, and ester-forming derivatives thereof can be used.

  Examples of the glycol component of polyester include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, , 6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol Neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2, 4-trimethyl-1,6-hexanediol, 1,2-cyclo Xanthodimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol, bisphenol A, 4,4′-methylenediphenol, 4,4 ′-(2-norbornylidene) diphenol, 4,4′-dihydroxybiphenol, o-, m-, and p-dihydroxybenzene, 4,4′-isopropylidenephenol 4,4′-isopropylidenediol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol, and the like can be used.

  In addition, when using polyester as an aqueous liquid as a coating liquid, a compound containing a carboxylic acid (salt) group or a compound containing a sulfonic acid (salt) group is used to facilitate water-solubilization or water-dispersion of the polyester. It is preferable to copolymerize a compound containing a phosphonic acid (salt) group.

  Examples of the compound containing a carboxylic acid (salt) group include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid, 1 , 2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 5- (2,5-dioxotetrahydro Furfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-cyclohexene-1,2-dicarboxylic acid, cyclopentanetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, ethylene glycol bistrimellite 2,2 ′, 3,3′-diphenyltetracarboxylic acid, thiophene-2,3,4,5-tetracarboxylic acid, ethylenetetracarboxylic acid, etc., or alkali metal salts, alkaline earth metal salts thereof, An ammonium salt etc. can be mentioned.

  Examples of the compound containing a sulfonic acid (salt) group include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, sulfo-p-xylylene glycol, 2-sulfo-1,4-bis (hydroxyethoxy) benzene or the like, or an alkali metal salt, alkaline earth metal salt, or ammonium salt thereof can be used.

  Examples of the compound containing a phosphonic acid (salt) group include phosphoterephthalic acid, 5-phosphoisophthalic acid, 4-phosphoisophthalic acid, 4-phosphonaphthalene-2,7-dicarboxylic acid, phospho-p-xylylene glycol, 2-phospho-1,4-bis (hydroxyethoxy) benzene or the like, or an alkali metal salt, alkaline earth metal salt, or ammonium salt thereof can be used.

  In the present invention, for example, a modified polyester copolymer such as a block copolymer or a graft copolymer modified with acrylic, urethane, epoxy, or the like can be used as the polyester.

  Preferred polyesters include those selected from terephthalic acid, isophthalic acid, sebacic acid, 5-sodium sulfoisophthalic acid as the acid component, and ethylene glycol, diethylene glycol, 1,4-butanediol, and neopentyl glycol as the glycol component. And the like. When water resistance is required, a copolymer or the like containing trimellitic acid as its copolymer component can be suitably used instead of 5-sodium sulfoisophthalic acid.

  The polyester can be produced by the following production method. For example, a polyester having a dicarboxylic acid component consisting of terephthalic acid, isophthalic acid, and 5-sodium sulfoisophthalic acid and a glycol component consisting of ethylene glycol and neopentyl glycol can be directly esterified with these monomers. Or it can manufacture by the method etc. which manufacture by the 1st step which transesterifies, and the 2nd step which carries out the polycondensation reaction of the reaction product of this 1st step.

  At this time, for example, alkali metal, alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, titanium compound, or the like can be used as the reaction catalyst.

  Further, as a method for obtaining a polyester having many carboxyl groups at the terminal and / or side chain, JP-A-54-46294, JP-A-60-209073, JP-A-62-240318, JP JP 53-26828, JP 53-26829, JP 53-98336, JP 56-116718, JP 61-124684, JP 62-240318 Although it can be produced by copolymerizing a trivalent or higher polyvalent carboxylic acid described in the gazette, etc., other methods may be used.

  Further, as the water-dispersed polyester resin, for example, a commercially available “Vaironal (registered trademark)” series (manufactured by Toyobo Co., Ltd.) can also be used.

  The intrinsic viscosity of the polyester is not particularly limited, but is preferably 0.3 dl / g or more in terms of adhesiveness, more preferably 0.35 dl / g or more, and most preferably 0.4 dl / g or more. It is. The glass transition temperature (hereinafter sometimes abbreviated as Tg) of the polyester is preferably 0 to 130 ° C, more preferably 10 to 85 ° C. Use of polyester with a Tg of 0 ° C. or higher improves heat-resistant water adhesion, and also suppresses blocking phenomena such as winding one end after laminating an adhesion improving layer on the surface of a polyester base film. Can do. Moreover, stability and water dispersibility can be favorably maintained by using polyester with Tg of 130 ° C. or lower.

[Polyurethane for adhesive improvement layer]
Next, polyurethane will be described. The polyurethane is not particularly limited as long as it has a urethane bond, and the main component is obtained by polymerizing a polyol compound and a polyisocyanate compound.

  Examples of the polyol compound include polyethylene glycol, polypropylene glycol, polyethylene / propylene glycol, polytetramethylene glycol, hexamethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5-pentanediol, diethylene glycol, triethylene glycol, polycaprolactone. Polyhexamethylene adipate, polytetramethylene adipate, trimethylolpropane, trimethylolethane, glycerin, acrylic polyol and the like can be used.

  Examples of the polyisocyanate compound include tolylene diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, an adduct of tolylene diisocyanate and trimethylolpropane, an adduct of hexamethylene diisocyanate and trimethylolethane, and the like. it can.

  In the synthesis of the polyurethane, a known chain extender, a crosslinking agent, and the like may be included in addition to the polyol compound and the polyisocyanate compound. As the chain extender or crosslinking agent, ethylene glycol, propylene glycol, butanediol, diethylene glycol, ethylenediamine, diethylenetriamine, or the like can be used.

  In order to obtain a stable polyurethane water dispersion, it is preferable to synthesize polyurethane having an increased affinity for water. Specifically, an appropriate amount of anionic groups may be introduced into the polyurethane. For example, a method of using a compound having an anionic group for polyol, polyisocyanate, chain extender, etc., a method of reacting an unreacted isocyanate group of the produced polyurethane with a compound having an anionic group, or having an active hydrogen of polyurethane It can be produced by a method of reacting a group with a specific compound.

  The anionic group in the polyurethane is preferably used as a sulfonic acid group, a carboxylic acid group, and an ammonium salt, lithium salt, sodium salt, potassium salt or magnesium salt thereof.

  The amount of the unit having an anionic group in the polyurethane is preferably 0.05% by mass to 15% by mass from the viewpoint of water dispersibility of the polyurethane.

  For example, as a polyurethane water dispersion, “Hydran (registered trademark)” series (manufactured by Dainippon Ink & Chemicals, Inc.) can be used.

[Acrylic polymer for adhesive improvement layer]
Examples of the monomer component constituting the acrylic polymer include, for example, alkyl acrylate, alkyl methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and t-butyl groups. Hydroxy group-containing monomers such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate), 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.) ; (Meth) acrylamide N-methyl (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-phenyl (meth) acrylamide, etc. Amino group-containing monomer such as N, N-diethylaminoethyl (meth) acrylate; epoxy group-containing monomer such as glycidyl (meth) acrylate; (meth) acrylic acid and salts thereof (lithium salt, sodium salt, A monomer containing a carboxyl group such as potassium salt or the like or a salt thereof can be used, and these are (co) polymerized using one kind or two or more kinds. Furthermore, these can be used in combination with other types of monomers.

  Examples of other types of monomers include epoxy group-containing monomers such as allyl glycidyl ether; sulfonic acids such as styrene sulfonic acid, vinyl sulfonic acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.) Monomer containing a group and a salt thereof; a monomer containing a carboxyl group or a salt thereof such as crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.) Monomers containing acid anhydrides such as maleic anhydride and itaconic anhydride; vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoe Ether, acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate, may be used vinyl chloride.

  Moreover, as said acrylic polymer, a modified acrylic polymer, for example, a block copolymer modified with polyester, polyurethane, epoxy resin, etc., a graft copolymer, etc. can be used.

  The lower limit of the acrylic polymer Tg is preferably −10 ° C. from the viewpoints of heat resistant water adhesion and blocking resistance, more preferably the lower limit is 0 ° C., and the most preferable lower limit is 10 ° C. On the other hand, the Tg of the acrylic polymer is preferably 90 ° C. from the viewpoint of heat resistant water adhesion and film-forming property, more preferably 50 ° C., and most preferably 40 ° C. Further, the weight average molecular weight (Mw) of the acrylic polymer is preferably 50,000 or more, and more preferably 300,000 or more from the viewpoint of heat resistant water adhesion.

  Preferable examples of the acrylic polymer include copolymers composed of monomers selected from methyl methacrylate, ethyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-methylol acrylamide, and acrylic acid.

  It is preferable to dissolve, emulsify, or suspend an acrylic polymer in water and use it as an aqueous liquid from the viewpoint of environmental pollution and explosion-proof properties during coating. Such water-based acrylic polymers are copolymerized with monomers having a hydrophilic group (acrylic acid, methacrylic acid, acrylamide, vinyl sulfonic acid and salts thereof, etc.) and emulsion polymerization using reactive emulsifiers and surfactants, It can be prepared by a method such as suspension polymerization or soap-free polymerization.

  Commercially available acrylic emulsions may also be used, for example, “Jonkrill (registered trademark)” series (manufactured by BASF Japan).

[Crosslinking agent used in adhesive improvement layer]
In the present invention, the polyester, polyurethane and acrylic polymer are preferably crosslinked. When the above polymer is cross-linked using a cross-linking agent, the cross-linking agent may be any one that can cross-link with a functional group present in the above-described polymer, such as a carboxyl group, a hydroxyl group, a methylol group, an amide group, or the like. . For example, melamine crosslinking agent, oxazoline crosslinking agent, isocyanate crosslinking agent, aziridine crosslinking agent, epoxy crosslinking agent, methylolated or alkylolized urea, acrylamide, polyamide resin, amide epoxy compound, various silanes A coupling agent, various titanate coupling agents, etc. can be used. In particular, a melamine-based crosslinking agent and an oxazoline-based crosslinking agent can be suitably used from the viewpoints of compatibility with the above-described polymer, heat resistant water adhesion, and the like.

  The melamine-based crosslinking agent is not particularly limited, but is a melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, a compound partially or completely etherified by reacting a methylolated melamine with a lower alcohol, or these A mixture of the above can be used. Moreover, as a melamine type crosslinking agent, a monomer, the condensate which consists of a multimer more than a dimer, these mixtures, etc. can be used. As the lower alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like can be used. Methylolated melamine resins such as methylated trimethylolmelamine and butylated hexamethylolmelamine are preferred. Furthermore, in order to accelerate | stimulate the thermosetting of a melamine type crosslinking agent, you may use acidic catalysts, such as p-toluenesulfonic acid, for example.

  Further, the oxazoline-based crosslinking agent is not particularly limited as long as it has an oxazoline group as a functional group in the compound, but includes at least one monomer containing an oxazoline group, and at least one kind of What consists of an oxazoline group containing copolymer obtained by copolymerizing another monomer is preferable.

  Monomers containing an oxazoline group include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like can be used, and one or a mixture of two or more thereof can also be used. Of these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially.

  In the oxazoline group-containing copolymer, the at least one other monomer used together with the oxazoline group-containing monomer is not particularly limited as long as it is a monomer copolymerizable with the oxazoline group-containing monomer. (Meth) acrylates or methacrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate; non-acrylic acid, methacrylic acid, itaconic acid, maleic acid, etc. Saturated carboxylic acids; unsaturated nitriles such as (meth) acrylonitrile; unsaturated amides such as (meth) acrylamide and N-methylol (meth) acrylamide; vinyl esters such as vinyl acetate and vinyl propionate; methyl vinyl ether and ethyl Vinyl ethers such as nyl ether; olefins such as ethylene and propylene; halogen-containing α-β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; α, β-unsaturated such as styrene and α-methylstyrene Saturated aromatic monomers etc. can be used and these can use 1 type, or 2 or more types of mixtures.

  As the oxazoline group-containing polymer, for example, “Epocross (registered trademark)” series (manufactured by Nippon Shokubai Co., Ltd.) is available.

  The isocyanate-based crosslinking agent is not particularly limited as long as it has an isocyanate group as a functional group in the compound, but it is preferable to use a polyfunctional isocyanate compound containing two or more isocyanate groups in one molecule. .

  As the polyfunctional isocyanate compound, a low-molecular or high-molecular aromatic or aliphatic diisocyanate or a trivalent or higher polyisocyanate can be used. Examples of the polyisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds. Furthermore, an excess amount of these isocyanate compounds and low molecular active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, or polyester polyols, poly The terminal isocyanate group containing compound obtained by making it react with polymer active hydrogen compounds, such as ether polyols and polyamides, can be mentioned.

  In addition, when using an isocyanate compound as a crosslinking agent, it is also possible to use a blocked isocyanate compound. The blocked isocyanate can be prepared by subjecting the above isocyanate compound and blocking agent to an addition reaction by a conventionally known appropriate method. Examples of the isocyanate blocking agent include phenols such as phenol, cresol, xylenol, resorcinol, nitrophenol and chlorophenol; thiophenols such as thiophenol and methylthiophenol; oximes such as acetoxime, methylethylketoxime and cyclohexanone oxime; Alcohols such as methanol, ethanol, propanol and butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; tertiary alcohols such as t-butanol and t-pentanol; -Lactams such as caprolactam, δ-valerolactam, γ-butyrolactam, β-propyllactam; aromatic amines; imides; acetylacetone, acetoacetate, malonic acid Active methylene compounds such as glycol ester; mercaptans; imines; ureas; diaryl compounds; can be mentioned sodium bisulfite and the like.

  The epoxy-based crosslinking agent is not particularly limited as long as it has an epoxy group as a functional group in the compound. However, it is preferable to use a polyfunctional epoxy compound having two or more epoxy groups in one molecule. .

  Examples of the polyfunctional epoxy compound include diglycidyl ether of bisphenol A and oligomer thereof, diglycidyl ether of hydrogenated bisphenol A and oligomer thereof, orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p-oxybenzoic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, ethylene glycol diglycidyl ether, propylene Glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and Polyalkylene glycol diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidyl propylene urea, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl Examples include ether, triglycidyl ether of glycerol alkylene oxide adduct, and the like.

  As the cross-linking agent, a phenol formaldehyde resin of a condensate with formaldehyde such as alkylated phenols and cresols; an adduct of urea, melamine, benzoguanamine and the like with formaldehyde, this adduct and an alcohol having 1 to 6 carbon atoms An amino resin such as an alkyl ether compound consisting of can also be used.

  Examples of the phenol formaldehyde resin include alkylated (methyl, ethyl, propyl, isopropyl or butyl) phenol, p-tert-amylphenol, 4,4′-sec-butylidenephenol, p-tert-butylphenol, o-, m-, p-cresol, p-cyclohexylphenol, 4,4'-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-pentadecylphenol, phenol, phenyl-o-cresol, p-phenylphenol, xylenol, etc. And the condensates of phenols and formaldehyde.

  Examples of amino resins include methoxylated methylol urea, methoxylated methylol N, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, butoxylated methylol benzoguanamine, and the like. Are preferably methoxylated methylol melamine, butoxylated methylol melamine, methylolated benzoguanamine, and the like.

  The polymer (polyester, polyurethane, acrylic polymer) and the crosslinking agent can be mixed and used in an arbitrary ratio. However, in order to express the hot water adhesive effect of the present invention more remarkably, the crosslinking agent is: The addition of 2 to 50 parts by mass with respect to 100 parts by mass of the polymer is preferred, more preferably 3 to 25 parts by mass. When the addition amount of the crosslinking agent is less than 2 parts by mass, the effect of addition is small, and when it exceeds 50 parts by mass, the hot water resistant adhesiveness tends to be lowered.

[Self-crosslinking polymer for adhesive improvement layer]
In the present invention, in addition to the above method, for example, the adhesion improving layer may be formed using a self-crosslinking type polymer in which a crosslinkable functional group is introduced into the above-described polymer. In the case of using a self-crosslinking type polymer, the crosslinking method may be, for example, thermal crosslinking, or may be crosslinking with high energy active rays such as ultraviolet rays, electron beams and γ rays.

  Hereinafter, a specific method will be illustrated for the case of polyester as the self-crosslinking polymer.

  The self-crosslinking type polyester preferably used in the present invention is a polyester graft copolymer obtained by grafting a hydrophobic copolymer polyester with a compound having at least one radical polymerizable double bond. The “grafting” of the polyester-based graft copolymer in the present invention is to introduce a branched polymer made of a polymer different from the main chain into the backbone polymer which is the main chain. Graft polymerization is usually carried out by reacting at least one radically polymerizable monomer using a radical initiator in a state where a hydrophobic copolyester is dissolved in an organic solvent. Hydrophobic copolyesters are essentially water-insoluble polyesters that do not inherently dissolve in water, so they are more heat resistant than using polyester resins that are soluble in water as the backbone polymer for graft polymerization. Excellent water adhesion.

  The hydrophobic copolyester is composed of 60 to 99.5 mol% of aromatic dicarboxylic acid, 0 to 39.5 mol% of aliphatic dicarboxylic acid and / or alicyclic dicarboxylic acid in 100 mol% of dicarboxylic acid component, radical It is preferable that the dicarboxylic acid containing a polymerizable double bond is 0.5 to 10 mol%. More preferably, the aromatic dicarboxylic acid is 68 to 98 mol%, the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid is 0 to 30 mol%, and the dicarboxylic acid containing a polymerizable unsaturated double bond is 2 to 7 Mol%.

  When the aromatic dicarboxylic acid is 60 mol% or more and the aliphatic dicarboxylic acid and / or alicyclic dicarboxylic acid is 39.5 mol% or less, the heat resistant water adhesion is good. Moreover, the grafting of the radically polymerizable monomer with respect to the polyester resin can be efficiently performed by using 0.5 mol% or more of the dicarboxylic acid containing a radically polymerizable double bond. On the other hand, the content of 10 mol% or less is preferable because the viscosity of the reaction solution can be prevented from significantly increasing in the later stage of the grafting reaction, and the reaction can proceed uniformly.

  As the aromatic dicarboxylic acid, aliphatic and / or alicyclic dicarboxylic acid, any of the compounds exemplified above can be used. Examples of the dicarboxylic acid containing a radically polymerizable double bond include fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, and other α, β-unsaturated dicarboxylic acids; 2,5-norbornene dicarboxylic acid anhydride And alicyclic dicarboxylic acids containing unsaturated double bonds such as tetrahydrophthalic anhydride. Of these dicarboxylic acids containing a polymerizable unsaturated double bond, fumaric acid, maleic acid, and 2,5-norbornene dicarboxylic acid are preferred from the viewpoint of polymerizability.

  As the glycol component, any of the compounds exemplified above can be used. Two or more glycol components may be used in combination. Especially, C2-C10 aliphatic glycol, C6-C12 alicyclic glycol, etc. are preferable.

  The hydrophobic copolymerized polyester may be copolymerized with 0 to 5 mol% of a trifunctional or higher polycarboxylic acid and / or polyol. The tri- or higher functional polycarboxylic acid includes (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) benzophenone tetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydrotrimellitate), glycerol tris (an Hydrotrimellitate) and the like. As the trifunctional or higher functional polyol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, or the like is used.

  The tri- or higher functional polycarboxylic acid and / or polyol is copolymerized in the range of 0 to 5 mol%, preferably 0 to 3 mol%, based on the total acid component or the total glycol component. Gelation can be suppressed.

  In addition, the lower limit of the weight average molecular weight of the hydrophobic copolyester is preferably 5,000 from the viewpoint of heat resistant water adhesion. Moreover, it is preferable that an upper limit is 50,000 at points, such as gelatinization at the time of superposition | polymerization.

  After the hydrophobic copolyester is synthesized, graft polymerization is performed. Graft polymerization is performed by reacting at least one radical polymerizable monomer using a radical initiator in a state where the hydrophobic copolyester is dissolved in an organic solvent. The reaction product after completion of the grafting reaction is not limited to the graft copolymer of the desired hydrophobic copolymerized polyester and the radically polymerizable monomer, but also the hydrophobic copolymerized polyester and the hydrophobic copolymer that were not subjected to grafting. It also contains a (co) polymer obtained from a radically polymerizable monomer that has not been grafted to the polyester. The polyester-based graft copolymer in the present invention includes not only the above-described polyester-based graft copolymer, but also a hydrophobic copolymerized polyester that has not been grafted, and a radically polymerizable monomer that has not been grafted. Also included are reaction mixtures containing the resulting (co) polymer and monomer (residual monomer).

In the present invention, the acid value of a reaction product obtained by graft polymerization of a radically polymerizable monomer to a hydrophobic copolymerized polyester is preferably 600 eq / 10 ⁶ g or more from the viewpoint of heat resistant water adhesion. More preferably, the acid value of the reactant is 1200 eq / 10 ⁶ g or more. When the acid value of the reaction product is less than 600 eq / 10 ⁶ g, the hot water adhesion may be lowered.

  The mass ratio of the desired hydrophobic copolymerized polyester and the radical polymerizable monomer suitable for the purpose of the present invention is preferably in the range of polyester / radical polymerizable monomer = 40/60 to 95/5, more preferably 55/45. ~ 93/7, most desirably in the range of 60/40 to 90/10.

  By setting the mass ratio of the hydrophobic copolyester to 40% by mass or more, the excellent adhesiveness of the polyester can be exhibited. On the other hand, when the mass ratio of the hydrophobic copolymerized polyester is 95% by mass or less, the blocking resistance can be improved and the acid value of the reaction product can be adjusted to the above range.

  The graft polymerization reaction product is in the form of an organic solvent solution or dispersion or an aqueous solvent solution or dispersion. In particular, a dispersion of an aqueous solvent, that is, a form of an aqueous dispersion is preferable in terms of working environment and applicability. Therefore, as the radical polymerizable monomer to be grafted, it is preferable to use a radical polymerizable monomer that essentially contains a hydrophilic radical polymerizable monomer. And after carrying out the graft polymerization in an organic solvent, the aqueous dispersion can be obtained by distilling off the organic solvent and adding water.

  The hydrophilic radical polymerizable monomer means a radical polymerizable monomer having a hydrophilic group or a group that can be changed to a hydrophilic group later. Examples of the radical polymerizable monomer having a hydrophilic group include a radical polymerizable monomer containing a carboxyl group, hydroxyl group, phosphoric acid group, phosphorous acid group, sulfonic acid group, amide group, quaternary ammonium base and the like. . On the other hand, examples of the radical polymerizable monomer having a group that can be changed into a hydrophilic group include radical polymerizable monomers containing an acid anhydride group, a glycidyl group, a chloro group, and the like. Among these, from the viewpoint of water dispersibility, a carboxyl group is preferable, and a radical polymerizable monomer having a carboxyl group or a group capable of generating a carboxyl group is preferable.

  In order to make the acid value of the graft reaction product within the above preferred range, it is preferable that a radical polymerizable monomer containing a carboxyl group or having a group capable of generating a carboxyl group is contained. Such monomers include fumaric acid, monoethyl fumarate; maleic acid and its anhydride, monoethyl maleate; itaconic acid and its anhydride, monoester of itaconic acid; acrylic acid, methacrylic acid; and salts thereof (sodium Salt, potassium salt, ammonium salt) and the like. Maleic anhydride is preferable. The said monomer can be copolymerized using 1 type, or 2 or more types.

  The radically polymerizable monomer to be grafted may contain other types of monomers as long as the acid value is within the above-mentioned preferable range. As other types of monomers, monomers that can be used when synthesizing the acrylic polymer described above can be used as they are.

  Examples of the graft polymerization initiator used in the present invention include organic peroxides and organic azo compounds known to those skilled in the art. Examples of the organic peroxide include benzoyl peroxide, t-butyl peroxypivalate, and examples of the organic azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2, 4-dimethyl pareronitrile). The amount of the polymerization initiator used for the graft polymerization is at least 0.2% by mass, preferably 0.5% by mass or more, based on the radical polymerizable monomer.

  In addition to the polymerization initiator, a chain transfer agent for adjusting the chain length of the branched polymer, for example, octyl mercaptan, mercaptoethanol, 3-t-butyl-4-hydroxyanisole may be used as necessary. In this case, it is desirable to add in the range of 0 to 5% by mass with respect to the polymerizable monomer.

  The grafting reaction product is preferably neutralized with a basic compound, and can be easily dispersed in water by neutralization. As the basic compound, a compound that volatilizes at the time of coating film formation is desirable, and ammonia, organic amines, and the like are preferable. Desirable compounds include, for example, triethylamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine , 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanol An amine etc. can be mentioned.

  The basic compound has a pH value of the aqueous dispersion in the range of 5.0 to 9.0 by at least partial neutralization or complete neutralization, depending on the carboxyl group content contained in the grafting reaction product. It is desirable to use it. If a basic compound with a boiling point of 100 ° C. or less is used, there are few residual basic compounds in the coating film after drying, and for example, improved hot water adhesion in harsh environments such as high temperature and humidity To do.

  In the grafting reaction product, the weight average molecular weight of the polymer of the radical polymerizable monomer is preferably 500 to 50,000. It is generally difficult to control the weight average molecular weight of the polymer of the radical polymerizable monomer to be less than 500, the graft efficiency is lowered, and there is a tendency that hydrophilic groups are not sufficiently imparted to the copolymer polyester. In addition, the graft polymer of the radical polymerizable monomer forms a hydrated layer of dispersed particles. To obtain a stable aqueous dispersion with a sufficient thickness of the hydrated layer, the graft polymer of the radical polymerizable monomer is used. The weight average molecular weight of is desirably 500 or more.

  The upper limit of the weight average molecular weight of the graft polymer of the radical polymerizable monomer is preferably 50,000 from the viewpoint of polymerizability in solution polymerization. In order to make the weight average molecular weight of the graft polymer of the radical polymerizable monomer within the range of 500 to 50,000, the initiator amount, the monomer dropping time, the polymerization time, the reaction solvent, the monomer composition, or the chain as necessary. It is preferable to carry out by appropriately combining a transfer agent and a polymerization inhibitor.

  The glass transition temperature of the graft copolymer is not particularly limited, but it is preferably 20 ° C. or higher, more preferably 40 ° C. or higher in consideration of heat resistant water adhesion.

  In the present invention, a reaction product obtained by graft polymerization of a radically polymerizable monomer to a hydrophobic copolymerized polyester has a self-crosslinking property because a hydroxyl group in the polyester and a carboxyl group present in the graft portion react. Moreover, although it does not bridge | crosslink at normal temperature, it carries out intermolecular reaction, such as a hydrogen abstraction reaction by a thermal radical, with the heat at the time of drying at the time of coating-film formation, and bridge | crosslinks without a crosslinking agent. As a result, a high degree of heat-resistant water adhesion is exhibited. The degree of crosslinking of the coating film can be evaluated by various methods, and examples thereof include a method of measuring the insoluble fraction in a chloroform solvent or the like that dissolves both the hydrophobic copolymerized polyester and the grafted polymer.

  The insoluble fraction of the coating film obtained by drying at about 80 ° C. and heat-treating at 120 ° C. for 5 minutes is preferably 50% by mass or more, more preferably 70% by mass from the viewpoints of heat resistant water adhesion and blocking resistance. That's it.

  As the self-crosslinking polyester resin aqueous dispersion, for example, a commercially available product such as “Vylonal (registered trademark) AGN702” (manufactured by Toyobo Co., Ltd.) can be used.

  In addition, a grafted polyurethane can be prepared by a method similar to the above.

[Additive for adhesive improvement layer]
Various additives such as an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, an organic lubricant, a pigment, and a dye are used in the adhesive improvement layer within the range in which the effects of the present invention are not impaired. Organic or inorganic particles, fillers, antistatic agents, nucleating agents and the like may be blended.

  In particular, when an inorganic particle is added to the adhesion improving layer, for example, when the adhesion improving layer is laminated on the surface of a polyester base film and wound once, the slipperiness and blocking resistance are improved. Therefore, it is preferable. In this case, silica, colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate, or the like can be used as the inorganic particles to be added. The average particle size used is preferably 0.005 to 5 μm, more preferably 0.01 to 3 μm, and most preferably 0.05 to 2 μm. Although the usage-amount of an inorganic particle is not specifically limited, It is preferable to mix 0.05-10 mass parts with solid content with respect to 100 mass parts of polymers in an adhesive improvement layer, More preferably, 0.1-5 mass parts It is.

[Method for forming adhesion improving layer]
The adhesion improving layer is formed from an aqueous dispersion of a mixture of at least one polymer selected from the group consisting of polyester, polyurethane and acrylic polymer and a crosslinking agent, or an aqueous dispersion of a self-crosslinking polymer. Therefore, it is most convenient to form by a coating method. What is necessary is just to apply | coat the coating liquid for adhesive improvement layers to the single side | surface or both surfaces of a polyester-type base film. In addition, any method such as a method of applying to an unstretched film of a polyester base film and then stretching in at least one direction, a method of applying after longitudinal stretching, and a method of applying to the film surface after orientation treatment are possible. is there. Among them, when producing a polyester-based substrate film, a so-called in-line coating method is applied before the crystal orientation of the film is completed, and then stretched in at least one direction, and then the crystal orientation of the polyester film is completed. Since the thin film can be easily formed, the effects of the present invention can be expressed more significantly, which is preferable.

  For example, when applying a coating solution for an adhesion improving layer to an unstretched film of a polyester base film, various coating methods such as reverse coating, gravure coating, rod coating, bar coating, Meyer A bar coating method, a die coating method, a spray coating method, or the like can be used.

  In the present invention, the adhesion improving layer is preferably provided between the polyester base film and the silicone rubber adhesive layer, but between the other adhesive layer of the double-sided adhesive sheet and the polyester base film. In addition, an adhesion improving layer may be provided.

[Second adhesive layer]
The other adhesive layer (second adhesive layer) of the double-sided adhesive sheet used in the present invention may be a silicone rubber layer similar to the first adhesive layer described above. In this case, the silicone rubbers of the first adhesive layer and the second adhesive layer may be the same, or may have different compositions and molecular weights.

  The second adhesive layer may be an acrylic adhesive layer. The pressure-sensitive adhesive constituting the acrylic pressure-sensitive adhesive layer is, for example, an acrylic containing an acrylic polymer whose main monomer component is (meth) acrylate having an alkyl group having 1 to 18 carbon atoms as a main monomer or base polymer. System adhesives.

  Examples of the (meth) acrylate having an alkyl group having 1 to 18 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, Isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) Examples include acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl acrylate (meth) acrylate, decyl acrylate (meth) acrylate, and dodecyl (meth) acrylate. These (meth) acrylates can be used alone or in admixture of two or more.

  Moreover, the monomer component (copolymerizable monomer) which has a copolymerizability with the said (meth) acrylate may be used. In particular, when the acrylic polymer is cross-linked, the copolymerizable monomer is preferably a monomer for modifying the acrylic pressure-sensitive adhesive, and any known monomer for modifying can be used. The copolymerizable monomers can be used alone or in combination of two or more.

  Specifically, as the copolymerizable monomer, any of the monomer components constituting the acrylic polymer for the adhesion improving layer and the monomers exemplified as other types of monomers can be used. Further, α- Examples include olefinic monomers.

  As the modifying monomer, the functional group-containing monomer is preferable, and among these, a hydroxyl group-containing monomer and a carboxyl group-containing monomer are preferable, and acrylic acid is particularly preferable. The acrylic polymer can be crosslinked using a functional group (particularly a polar group) derived from the modifying monomer.

  Polymerization methods for obtaining acrylic polymers include solution polymerization methods using emulsion initiators such as azo compounds and peroxides, emulsion polymerization methods and bulk polymerization methods, and light and radiation using photoinitiators. A polymerization method performed by irradiation can be employed. In the present invention, a method of polymerizing using a polymerization initiator that decomposes to generate radicals (radical polymerization method) can be suitably employed. In this radical polymerization, polymerization initiators such as peroxides such as benzoyl peroxide and tert-butyl permaleate, and azo compounds such as 2,2′-azobisisobutyronitrile and azobisisovaleronitrile are usually used. To do. The amount of the polymerization initiator used may be the amount usually used in the polymerization of the acrylic monomer, and for example, about 0.005 to 10 parts by mass, preferably 0.1 to 100 parts by mass of the total amount of monomer components. About 5 parts by mass.

  The ratio of the (meth) acrylate having an alkyl group having 1 to 18 carbon atoms as the main monomer component of the acrylic polymer is 50% by mass or more with respect to 100% by mass of the monomer component from the viewpoint of adhesive properties. preferable. 80 mass% or more is more preferable, and 90 mass% or more is further more preferable. Therefore, the proportion of the copolymerizable monomer other than the (meth) acrylate is 50% by mass or less in 100% by mass of the monomer component.

  The acrylic polymer obtained by polymerizing the monomer component can be used as it is. It is also possible to cure the acrylic polymer by crosslinking. When the polymer is crosslinked, the cohesive force of the pressure-sensitive adhesive can be further increased. For crosslinking, a crosslinking agent can be used. That is, the acrylic pressure-sensitive adhesive may contain a crosslinking agent together with the acrylic polymer. For the crosslinking of the polymer, a heat crosslinking method is preferably used.

  As the crosslinking agent, any of the crosslinking agents exemplified as the crosslinking agent that can be used in the adhesion improving layer can be used. As the crosslinking agent, melamine crosslinking agent, epoxy crosslinking agent, and isocyanate crosslinking agent are particularly preferable. A crosslinking agent can be used individually or in mixture of 2 or more types. The amount of the melamine crosslinking agent and / or epoxy crosslinking agent used is preferably 0.001 to 10 parts by mass, and more preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the acrylic polymer. 0.01-20 mass parts is preferable with respect to 100 mass parts of acrylic polymers, and, as for the usage-amount of an isocyanate type crosslinking agent, 0.05-15 mass parts is more preferable.

  You may add various additives to an acrylic adhesive as needed. For example, a tackifier resin (for example, a rosin resin, a terpene resin, a petroleum resin, a coumarone / indene resin, a styrene resin, or the like) may be blended to adjust the adhesion characteristics. From the viewpoint of increasing the colorless transparency of the double-sided pressure-sensitive adhesive sheet and suppressing the change in color tone, a hydrogenated tackifying resin is preferable, and the blending ratio is preferably set in a range that does not increase the haze of the double-sided pressure-sensitive adhesive sheet. Further, as additives other than the tackifying resin, various known additives such as plasticizers, fillers such as fine powder silica, colorants, ultraviolet absorbers, surfactants and the like can be blended. The amount of these additives used may be a normal amount applied to the acrylic pressure-sensitive adhesive.

  The adhesive force of the acrylic pressure-sensitive adhesive layer can be controlled by a method such as a modification monomer (functional group-containing copolymerizable monomer), a ratio adjustment of a crosslinking agent, or a method using a surfactant. The thickness in particular of an acrylic adhesive layer is not restrict | limited, For example, 3-200 micrometers is preferable. 5-50 micrometers is more preferable and 10-30 micrometers is further more preferable.

  In addition, as the acrylic pressure-sensitive adhesive, for example, “SK Dyne” series manufactured by Soken Chemical Co., Ltd. can be used. Among these, use of a brand of optical pressure-sensitive adhesive is preferable.

  The formation method of the said acrylic adhesive layer is not limited. For example, a solution type coating solution of an organic solvent or a coating solution in the form of an aqueous dispersion is prepared and applied by a coating method. In addition, a layer having the same composition as the adhesion improving layer is provided between the acrylic pressure-sensitive adhesive layer and the polyester-based base film so that the adhesiveness between the acrylic pressure-sensitive adhesive layer and the base film is enhanced. May be.

  The adhesive strength of the acrylic pressure-sensitive adhesive layer may be the same as that of the silicone rubber adhesive layer, or may be small or large. It is preferable to select and set appropriately depending on the method of using the double-sided pressure-sensitive adhesive tape. For example, if both surfaces are set to be detachable, the adhesive strength of the silicone rubber adhesive layer is in the same range, that is, 0.01 to 1.0 N / 20 mm (180 ° peel test against glass, tensile speed 300 mm / The range of min) is preferred. On the other hand, when fixing one side firmly, it is good to set higher than the said range, and 5.0-25N / 20mm is a suitable range. A more preferable range is 8.0 to 20 N / 20 mm.

[Separate film]
The double-sided PSA sheet used in the present invention is used for bonding the laminate (1) and the conductive laminate (2), but before use, in order to protect the first adhesive layer and the second adhesive layer. In addition, it is desirable to attach and store a separate film for each.

  Although it does not specifically limit as a base material of a separate film, The polyester film illustrated as a polyester-type base film of a double-sided adhesive sheet is suitable.

[Peel strength between the release layer of the separate film and the first adhesive layer]
A separate film is obtained by providing a release layer on the polyester film. The release layer is preferably configured such that the peel strength with the silicone rubber pressure-sensitive adhesive layer falls within the range of 0.03 to 1.0 N / 20 mm. When the peel strength is 0.03 N / 20 mm or more, it exhibits good peelability, and when the double-sided pressure-sensitive adhesive sheet is wound up, the separation film can be prevented from floating, and the quality of the double-sided pressure-sensitive adhesive sheet can be kept high. Can do. On the other hand, if it is 1.0 N / 20 mm or less, the peelability of the said separate film is favorable. In order to control the peel strength within the above range, a release layer having the following constitution is preferably provided on the surface of the polyester film. The peel strength is measured as follows.

  First, the surface where the peel strength of a double-sided pressure-sensitive adhesive tape having a length of about 200 mm and a width of 20 mm is to be measured is exposed, and the double-sided pressure-sensitive adhesive sheet is divided into a laminate including one surface and a laminate including the other surface, Set each on the chuck of the tensile tester. That is, for example, when measuring the peel strength at the interface between the silicone rubber pressure-sensitive adhesive layer and the release layer of the separate film, the double-sided pressure-sensitive adhesive sheet is slightly peeled off at the interface between the silicone rubber pressure-sensitive adhesive layer and the release layer. Expose each of them. In this case, a separate film composed of a release layer and a polyester film is gripped by one chuck, and a double-sided pressure-sensitive adhesive sheet (desirably, a separate film is attached to the second pressure-sensitive adhesive surface) with one chuck. Grip. Then, the T-type peel strength is measured by the method described in JIS K6854-3. For example, a trade name “Autograph” (manufactured by Shimadzu Corporation) may be used as the tensile tester, and a T-type peel test is performed under conditions of a distance between chucks of 50 mm, a temperature of 23 ° C., and a tensile speed of 200 mm / min. During peeling, the end of the film is lifted with a stick so that the T-shape is maintained. The maximum strength at the time of T-type peeling is defined as peeling strength.

  Hereinafter, in the present invention, the above characteristic may be simply referred to as peelability.

[Release layer]
The release layer of the separate film adhered to the silicone rubber pressure-sensitive adhesive layer side of the double-sided pressure-sensitive adhesive sheet used in the present invention is only required to have a peel strength satisfying the above range, and considering the peelability from the silicone rubber pressure-sensitive adhesive layer. In other words, it is preferably made of a non-silicone compound. When the release layer is made of a cured product of a curable silicone compound that is widely used as a release layer, it has a high affinity with the silicone rubber adhesive layer. Therefore, when the silicone compound of the adhesive layer is crosslinked, the adhesive layer And the release layer may undergo a crosslinking reaction, and the peelability may decrease. In order to obtain stable peelability, the release layer is preferably formed using a release agent that does not substantially contain a silicone compound. Here, “the release layer is made of a non-silicone compound” means that the release layer is formed from a compound (or composition) containing 10% by mass or less of a silicone compound, and more preferable silicone. The compound amount is 5% by mass or less, and the silicone compound is most preferably 0% by mass. The release layer of the separate film attached to the second adhesive layer side may be the same compound (or composition) as the release layer of the separate film attached to the silicone rubber adhesive layer side. It may be a different compound (or composition).

  The release layer may be made of a metal or an inorganic thin film, but is obtained from a composition containing a binder resin, a polymer wax component, and an antistatic agent in terms of release stability and cost. It is preferable.

  The binder resin is preferably one or more polymers selected from the group consisting of polyesters, polyurethanes and acrylic polymers. These polymers may be used alone, or two or three different types may be used. May be used in combination.

  As the polyester, polyurethane, and acrylic polymer, the same polymers as those exemplified as the constituent polymer of the adhesion improving layer can be used. Although the need for crosslinking is low in the binder resin, a crosslinking agent may be used in combination with the adhesive improvement layer, or a self-crosslinking type polymer may be used.

  As the polymer wax component used in the present invention, conventionally known materials can be used. For example, wax emulsions such as polyethylene, polypropylene, acrylic, and fatty acid are shown, but a polymer wax agent that is particularly hard and does not have a sticky feeling and has excellent thermal decomposition stability is effective in improving peelability. Further, it is preferable because the transfer of wax to the opposite surface can be suppressed during film winding. Moreover, the preferable number average molecular weights of these wax agents are 1000-10000, More preferably, it is the range of 1500-6000.

  The polymer wax component is preferably contained in a solid content of 2 to 10% by mass when the total with the binder resin is 100% by mass. More preferably 3 to 8% by mass is contained. By making the addition amount of the polymer wax component 2% by mass or more, the peelability from the silicone rubber pressure-sensitive adhesive layer after the crosslinking treatment can be improved, and the slipperiness of the separate film can be improved. On the other hand, by setting the addition amount of the polymer wax component to 10% by mass or less, it is possible to maintain the peeling force and suppress the occurrence of the channeling phenomenon in the manufacturing process of the transparent conductive polyester film composite. Furthermore, since the migration of the polymer wax component from the release layer can be suppressed, the surface of the first adhesive layer after the crosslinking treatment is less likely to be contaminated.

  The antistatic agent used in the release layer is not particularly limited as long as it can be mixed with the binder resin or is compatible with the binder resin. For example, any of anionic, cationic, nonionic, amphoteric surfactants, polymer surfactants, and the like can be used. Preferably, a polymer type antistatic agent with little bleed out to the laminated surface is preferred.

  As the polymer type antistatic agent, any of anionic type, cationic type and nonionic type can be used, and among them, anionic type and nonionic type polymeric antistatic agents are suitable.

  As the anionic polymer antistatic agent, for example, a polar polymer having at least one polar group selected from a sulfonic acid group, a carboxyl group, and a sulfate ester group or a salt thereof is preferable. The polar group needs 5 mol% or more per polymer molecule. These polar polymers having electrical conductivity may contain hydroxyl groups, amino groups, epoxy groups, aziridine groups, active methylene groups, sulfinic acid groups, aldehyde groups, and vinyl sulfone groups as polar groups. Among these, an antistatic agent containing styrene sulfonic acid or a salt thereof as a repeating unit is preferable.

  Examples of such an antistatic agent include polystyrene sulfonic acid or a salt thereof. Examples of the salt include ammonium salt, lithium salt, and sodium salt. Polystyrene sulfonic acid or a salt thereof is, for example, commercially available from Nippon SC under the trade name VERSA-TL (registered trademark) and various types of unneutralized salts having different molecular weights. Further, as an antistatic agent containing styrene sulfonic acid or a salt thereof as a repeating unit, a styrene sulfonic acid-maleic acid copolymer can also be used and is commercially available from Nippon SC.

  On the other hand, nonionic high molecular surfactants include aniline or derivatives thereof, pyrrole or derivatives thereof, isothianaphthene or derivatives thereof, acetylene or derivatives thereof, thiophene or derivatives thereof, and the like. Is preferred. Among them, a π-electron conjugated conductive polymer containing thiophene or a derivative thereof as a structural unit is preferable because it is less colored. The π-electron conjugated conductive polymer may be a homopolymer containing only one type of structural unit as a repeating unit or a copolymer containing two or more types of structural units as a repeating unit.

  Examples of the conductive polymer containing thiophene or a derivative thereof as a constitutional unit include, for example, “BYTRON (registered trademark) P” series manufactured by Starck Vitech, and “Denatron (registered trademark) P-502RG” manufactured by Nagase ChemteX. "Denatron (registered trademark) P-502S", Conisole F202, F205, F210, P810 (above, trade name) manufactured by Instectech, CPS-AS-X03 (trade name) manufactured by Shin-Etsu Polymer, etc. are commercially available. .

  The blending amount of the antistatic agent in the release layer cannot be determined uniquely because the preferred range varies depending on the type of binder resin and the type of antistatic agent. Peel strength from the silicone rubber adhesive layer of the release layer However, they may be adjusted so as to be within the above ranges.

  For example, when an anionic surfactant is used as the antistatic agent, the blending amount of the antistatic agent is such that the peel strength from the silicone rubber adhesive layer of the release layer is within the above range. When the total is 100% by mass, the solid content is preferably 2 to 10% by mass, and more preferably 3 to 8% by mass. By making the compounding amount of the anionic surfactant 2% by mass or more, the peelability from the adhesive layer after the crosslinking treatment is improved, and the antistatic property of the separate film is also improved. On the other hand, by setting the blending amount of the antistatic agent to 10% by mass or less, it is possible to maintain the peeling force and suppress the occurrence of the channeling phenomenon in the manufacturing process of the transparent conductive polyester film composite. Furthermore, since the migration of the polymer wax component from the release layer can be suppressed, the surface of the pressure-sensitive adhesive layer after the crosslinking treatment is rarely contaminated.

  In order to form a release layer having the above structure on a polyester film, a predetermined amount of a binder resin, a polymer wax component, an antistatic agent, and other additives such as a surface roughening material are mixed in advance. Then, a resin composition may be prepared and applied. The resin composition may contain a surfactant for improving coatability, an ultraviolet ray inhibitor, an antioxidant, and the like. The coating method may be applied using a normal coating apparatus such as a gravure coater, reverse roll coater, reverse kiss coater, air knife coater, bar coater, etc., and the method is not limited to these. As in the case of the adhesion improving layer, when obtaining a polyester film, a resin composition is applied to one side of a film stretched in a uniaxial direction, and further stretched in a direction perpendicular to the previous uniaxial stretch, A so-called off-line coating method in which coating is performed after biaxial stretching is exemplified.

  The thickness of the release layer is preferably 0.03 to 1 μm and more preferably 0.05 to 0.5 μm in a dry state in order to make the peeling force within an appropriate range.

[Method for producing double-sided PSA sheet]
The production method of the double-sided pressure-sensitive adhesive sheet is not particularly limited, and the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are made of a polyester-based substrate film (preferably a polyester-based substrate film in which an adhesion improving layer is laminated on one side or both sides). And may be wound up via a separate film. The first adhesive layer and the second adhesive layer may be formed in this order, may be reversed, or both layers may be formed simultaneously.

[Laminate (1)]
The upper electrode for a touch panel of the present invention is a double-sided pressure-sensitive adhesive sheet that has been described so far, and a laminate (1) having a configuration in which a hard coat layer is laminated on a transparent substrate, and a transparent conductive layer is laminated on the transparent substrate. The conductive laminate (2) is bonded together.

  The laminate (1) is for preventing damage by a pen or the like used for a touch panel. For the hard coat layer, polyester resin, polyurethane resin, acrylic resin, melamine resin, epoxy resin, silicone resin, polyimide resin, etc., thermal crosslinking with a crosslinking agent, activity such as electron beam, ultraviolet ray, etc. A layer cured with light is preferred.

  The thickness of the hard coat layer is preferably in the range of 1 to 50 μm, and more preferably in the range of 2 to 30 μm. When the thickness is less than 1 μm, the function of the hard coat treatment is not sufficiently exhibited, and when the thickness exceeds 50 μm, the resin coating speed is remarkably slow, and it is difficult to obtain good results in terms of productivity.

  As a method of laminating a hard coat layer, the above resin is coated on a transparent substrate by a gravure method, a reverse method, a die method, etc., and then cured by applying energy such as heat, ultraviolet rays, an electron beam or the like. That's fine.

  Although it does not specifically limit as a transparent base material, Polyester resin which is a base material of an above-mentioned double-sided adhesive sheet, cyclic polyolefins, such as a norbornene-type polymer; Polyamide resin, such as nylon 6, nylon 4, nylon 66, nylon 12, etc .; Acrylic Examples of the resin include polycarbonate resin, polycarbonate, and triacetyl cellulose (TAC). The resin used for these films may be a copolymer containing a small amount of a copolymer component. In addition to using these resins alone, one or more other resins may be blended and used. In forming the film, the method may be the same as that exemplified for the production of the polyester base film. However, TAC is preferably formed into a film by a casting method. An adhesive improvement layer may be provided on the transparent base material of the laminate (1) before the hard coat layer is provided. Although the thickness of the transparent base material of a laminated body (1) is not specifically limited, 50-150 micrometers is preferable.

[Conductive laminate (2)]
The conductive laminate (2) is obtained by laminating a transparent conductive layer on a transparent substrate. As a transparent base material, the base material which can be used for the said laminated body (1) can be illustrated as it is. Also in this case, a suitable thickness is not particularly limited, but is preferably 5 to 30 μm.

  Typical transparent conductive materials include metals such as gold, silver and copper; metal oxides such as indium oxide, tin oxide and zinc oxide or composite oxides thereof; polyaniline, polyacetylene, polythiophene, polyparaphenylene, Examples thereof include conductive polymers such as polyparaphenylene vinylene and polypyrrole. Of these, metal oxides such as indium oxide, tin oxide, and zinc oxide, or composite oxides thereof are preferable. For these, one or more dopants may be used from tin oxide, zinc oxide, antimony oxide, tungsten oxide, zirconium oxide, silicon oxide, and the like. The content of the dopant is preferably in the range of 0.1 to 50 mass% with respect to the metal oxide or composite oxide. If the content is less than 0.1% by mass, the function as a dopant cannot be sufficiently exhibited, and if the content exceeds 50% by mass, the original characteristics of the metal oxide and composite oxide are impaired, which is not preferable. .

  In the case of producing a transparent conductive layer from the above conductive polymer, a known coating method may be used after dissolving in a suitable solvent.

  In order to form a transparent conductive layer on a transparent substrate using the above metals, metal oxides, and composite oxides, vacuum deposition, sputtering, CVD, ion plating, spraying, etc. can be employed. . For example, in the case of the sputtering method, a normal sputtering method using an oxide target, a reactive sputtering method using a metal target, or the like is used. At this time, oxygen, nitrogen, water vapor or the like may be introduced as a reactive gas, or means such as ozone addition, plasma irradiation, or ion assist may be used in combination. In addition, a bias such as direct current, alternating current, and high frequency may be applied to the substrate as long as the object of the present invention is not impaired.

  Moreover, the temperature at the time of forming a transparent conductive layer in a transparent base material is good to change suitably according to the heat-resistant temperature of a film. For example, if it is a polyester-type film, it is preferable to set it as 150 degrees C or less. In order to set the temperature at the time of film formation to a temperature exceeding 150 ° C., the film feed rate must be extremely slow, which is not preferable from the viewpoint of productivity.

  Moreover, it is preferable to perform the vacuum degree at the time of performing sputtering in the range of 0.01-10Pa. When the degree of vacuum is higher than 0.01 Pa, since stable discharge cannot be performed, sputtering is not stable. Moreover, even if the degree of vacuum is lower than 10 Pa, since stable discharge cannot be performed, sputtering is not stable. The same applies to other methods such as vapor deposition and CVD.

  The thickness of the transparent conductive layer is preferably in the range of 4 to 800 nm, particularly preferably 5 to 500 nm. When the thickness of the transparent conductive layer is less than 4 nm, it is difficult to form a continuous thin film, and it is difficult to exhibit good conductivity. On the other hand, when the thickness is larger than 800 nm, the transparency tends to decrease, which is not preferable.

[Method for manufacturing upper electrode for touch panel]
The method for producing the upper electrode for the touch panel is not particularly limited, and the separate film on the first adhesive layer side or the second adhesive layer side is peeled off and bonded to the laminate (1) or the conductive laminate (2). Then, the separate film on the second adhesive layer side or the first adhesive layer side may be peeled off and bonded to the laminate (2) or the conductive laminate (1). When a double-sided pressure-sensitive adhesive sheet having a configuration in which only one side is a silicone rubber layer is used, the silicone rubber pressure-sensitive adhesive layer is disposed on the laminate (1) side, and the laminate (1) and the conductive laminate (2) are bonded together. It is preferable. This is because the silicone rubber adhesive layer is disposed on the input screen side of the touch panel, and the cushioning property is effectively exhibited.

  Since the double-sided pressure-sensitive adhesive sheet appropriately controls the peel strength with the separate film, it is excellent in workability in these sticking steps. Moreover, since the silicone rubber pressure-sensitive adhesive layer that can be re-peeled even if there is a mistake in the sticking process, the yield is improved.

  In the upper electrode for touch panel of the present invention, the silicone rubber pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet used for this is firmly bonded to the base film, and the silicone rubber pressure-sensitive adhesive layer has excellent cushioning properties. Thus, reliability and durability are improved as compared with conventional touch panels.

[Optical characteristics of upper electrode for touch panel]
The upper electrode for a touch panel of the present invention preferably has a total light transmittance of 80% or more and a haze of 2.0% or less in applications where high transmittance is required. More preferably, the total light transmittance is 85% or more and the haze is 1.0% or less. Furthermore, it is preferable that the total light transmittance and haze are within the above-mentioned preferable range even after storage at 65 ° C. and 85 RH% for 200 hours.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, but may be implemented with appropriate modifications within a scope that can meet the gist of the present invention. These are all included in the technical scope of the present invention. The measurement / evaluation methods employed in the examples are as follows. In the examples, “parts” means “parts by mass”, and “%” means “% by mass” unless otherwise specified.

1. Adhesiveness A cutter knife was inserted between the silicone rubber pressure-sensitive adhesive layer and the polyester base film, and peeling was performed by applying force with a finger (exposing the interface). The case where the adhesion was strong and the interface could not be evaluated was evaluated as ◯, and the case where the interface could be aligned was evaluated as ×.

2. Heat-resistant water adhesion The double-sided pressure-sensitive adhesive sheet is cut into 50 mm × 50 mm, and the separate film on the silicone rubber pressure-sensitive adhesive layer side is peeled off. The sample is submerged in a cylindrical glass container with 400 cc of distilled water with a lid so that the adhesive layer is on the lower side, and the container is covered with the entire sample immersed in water. . In the case where the sample is not immersed in water by its own weight, for example, a polyester film having a size of 60 mm × 60 mm and a thickness of 188 μm may be placed on the sample and weighted. The size and material of the weight are not particularly limited, and the entire sample may be immersed in water. The container containing the sample is placed in a gear oven set at 80 ° C. and allowed to stand for 24 hours. After heat treatment, remove the container from the oven, quickly remove the sample, apply force with the finger pad from the adhesive layer side to the end and rub it 10 times, and evaluate whether the adhesive layer peels from the polyester base film side In addition, the case where the pressure-sensitive adhesive layer does not peel is indicated by ○, and the case where the pressure-sensitive adhesive layer peels is indicated by ×.

3. Adhesive strength The adhesive strength of the silicone rubber adhesive layer and the acrylic adhesive layer to glass was measured by a 180-degree peeling method according to JIS Z0237. As the glass, heat resistant glass having a thickness of 3 mm and a width of 30 mm was used. The sample had a width of 20 mm, and was attached to the glass by reciprocating twice at a speed of about 29 mm / second using a 2 kg roller. The tensile speed was 300 mm / min, a tensile test was performed in an atmosphere at 23 ° C., and the maximum tensile strength was the adhesive strength (N / 20 mm).

4). Total light transmittance and haze value Using a sample obtained by peeling a separate film from a double-sided pressure-sensitive adhesive sheet, the sample was measured using a haze measuring instrument “NDH-2000” manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS K7361-1.

5. Clarity of coating solution 100cc of each coating solution for forming silicone rubber adhesive layer is filtered with a wire mesh of 200mm (wire diameter 0.04mm) of 40mmφ, and the presence or absence of insoluble matter is confirmed with the naked eye. The case was marked with ○ and the case with insoluble matter was marked with ×.

6). Solution Stability of Coating Solution Each silicone rubber adhesive layer forming coating solution was evaluated by a change in viscosity of the solution when stored in a sealed state at room temperature (23 ° C.) for 90 days to determine solution stability. The case where the change in viscosity of the solution was within ± 20% was marked as ◯, and the case where the change in viscosity of the solution exceeded ± 20% was marked as x. The viscosity was measured with a B-type viscometer.

Example 1
(1) Preparation of coating solution for forming adhesive improvement layer [Preparation of water-dispersible copolyester resin]
Water-dispersible copolymerization using antimony trioxide as a polycondensation catalyst in a batchwise manner using one pressure esterification reaction tank with a distillation column and two polycondensation reaction tanks with a vacuum generator Polyester was synthesized.

  The copolymer composition of the water-dispersible copolymer polyester is terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // neopentyl glycol / ethylene glycol = 50/43/7 // 70/30 (molar ratio). The reduced viscosity was 0.68 dl / g.

[Preparation of coating solution]
100 parts of the pulverized product of the water-dispersible copolyester was dispersed in water by a conventional method. With respect to 100 parts of the solid content of this aqueous dispersion, 5 parts of methylol melamine resin “Cymel (registered trademark) 303” (manufactured by Mitsui Cytec Co., Ltd.) is used as the catalyst, and “Catalyst 600” (Mitsui Cytec Co., Ltd.) as the catalyst. Product) was added and stirred well to obtain a coating solution (No. 1).

(2) Production of polyester base film and lamination of adhesion improving layer Polyethylene terephthalate containing 0.04% of amorphous silica fine particles having an average particle size (SEM method) of 1.5 μm (inherent viscosity 0.65 dl / g) The pellets were sufficiently dried in vacuum, then supplied to an extruder heated to 280 ° C., extruded into a sheet form from a T-shaped die, and applied to a mirror casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method. It was wound and solidified by cooling. The unstretched film was stretched 3.5 times in the longitudinal direction while passing through a heating roll group at 95 ° C. to obtain a uniaxially stretched film. Both surfaces of this film were subjected to corona discharge treatment, and the coating liquid (No. 1) was applied to both treatment surfaces. The uniaxially stretched film was guided to a preheating zone while being held with a clip, dried at 110 ° C., and continuously stretched 3.5 times in the width direction in a heating zone at 125 ° C. Further, heat treatment was performed for 6 seconds at 225 ° C. while relaxing 6% in the width direction. A laminate (i) having a thickness of 12 μm was obtained, in which a cross-linked adhesive property improving layer having a thickness of 0.08 μm was laminated on both sides of the biaxially stretched polyethylene terephthalate base film.

(3) Preparation of release layer-forming coating solution “Vylonal (registered trademark) MD-1200” (manufactured by Toyobo Co., Ltd.), which is a water-dispersible copolyester resin, is used as a binder resin, and polyethylene is used as a polymer wax component. Emulsion wax agent, anionic antistatic agent (sodium dodecyldiphenyl oxide disulfonate) as antistatic agent, and styrene-benzoguanamine-based spherical organic particles having an average particle size of 2 μm as surface roughening substance “Eposter (registered trademark) MS (Manufactured by Nippon Shokubai Co., Ltd.) and colloidal silica having an average particle size of 0.05 μm were used.

  Using a homogenizer, the organic spherical fine particles of the surface roughening material are sufficiently dispersed in a mixed solution of water and isopropyl alcohol (mass ratio 80/20), and then the binder with respect to the total mass of the coating solution. Release layer with sufficient mixing so as to be 2.5% resin, 0.13% polymer wax component, 0.13% antistatic agent, 0.025% organic spherical fine particles, and 0.3% colloidal silica. A forming coating solution was prepared.

(4) Manufacture of separate film (Manufacture of polyester film and lamination of release layer)
Polyethylene terephthalate (intrinsic viscosity 0.65 dl / g) pellets are sufficiently dried in vacuum, then supplied to a heated 280 ° C. extruder, extruded into a sheet from a T-shaped die, and an electrostatic application casting method is used. Then, it was wound around a mirror casting drum having a surface temperature of 30 ° C. and solidified by cooling. The unstretched film was stretched 3.5 times in the longitudinal direction while passing through a heating roll group at 95 ° C. to obtain a uniaxially stretched film. The release layer-forming coating solution was applied to both surfaces of this uniaxially oriented film. The coated uniaxially stretched film was guided to a preheating zone while being held with a clip, dried at 110 ° C., and continuously stretched 3.5 times in the width direction in a heating zone at 125 ° C. Further, heat treatment was performed for 6 seconds at 225 ° C. while relaxing 6% in the width direction. A separate film having a thickness of 12 μm in which a release layer having a thickness of 0.15 μm was laminated on both sides of the polyester film was obtained.

(5) Lamination of silicone rubber pressure-sensitive adhesive layer Non-reactive material composed of an uncrosslinked polydimethylsiloxane skeleton having substantially no reinforcing agent such as silica and having a number average molecular weight of 150,000 (measured by GPC method, converted to polystyrene). A silicone compound (KF-96H-500,000 cs; manufactured by Shin-Etsu Chemical Co., Ltd.) was weighed so that the mass ratio to toluene was 23%, and was put together with toluene into a stirrer equipped with a vacuum deaerator, under atmospheric pressure. The mixture was stirred at room temperature for 15 hours and dissolved in toluene. To the obtained solution, trimethylolpropane trimethacrylate was added to 100 parts of the silicone compound so as to be 2 parts, and after stirring uniformly, the vacuum deaerator was driven and the gauge pressure was -750 mmHg. Stir under vacuum for another 20 minutes and degas. Next, the defoamed silicone compound solution is supplied to a roll coater, and the silicone compound solution is applied to one side of the laminate (i) so that the thickness after drying is 25 μm, and then introduced into an oven. Dry at 80 ° C. A laminate (ii) in which an uncrosslinked silicone rubber adhesive layer was formed on one side of the laminate (i) was obtained.

While the separate film was stacked on the surface of the uncrosslinked silicone rubber adhesive layer of the laminate (ii), it was pressed with a pressure roller (pressure 30 N / cm ² ) and continuously laminated. The obtained laminate (iii) is continuously introduced into an electron beam irradiation apparatus, and the adhesive layer is crosslinked by irradiating an electron beam with energy of 200 KV and 18 Mrad from the side of the separate film. The laminate (iv) provided with a layer was wound into a roll. In the manufacturing process so far, the occurrence of the channeling phenomenon of the separate film was not observed.

(6) Lamination of acrylic adhesive layer Thickness after drying SK Dyne 2094 (manufactured by Soken Chemical Co., Ltd.), an optical acrylic adhesive, on the surface of laminate (iv) on the laminate (i) side Was applied to a thickness of 25 μm and dried at 130 ° C. for 3 minutes to form an acrylic pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer was laminated so that the silicone-treated surface side of a 12 μm-thick separate film (E7002; manufactured by Toyobo Co., Ltd.) made of silicone-treated polyethylene terephthalate was in contact with each other to obtain a double-sided pressure-sensitive adhesive sheet. The characteristic of the obtained double-sided pressure-sensitive adhesive sheet is shown on the display. Even in this process, the occurrence of the channeling phenomenon of the separate film was not observed.

(7) Manufacture of Laminate (1) with Hard Coat Layer Laminated on Transparent Substrate UV Curing Hard Coat Paint on One Side of Polyester Film (Cosmo Shine (registered trademark) A4300; manufactured by Toyobo Co., Ltd .; 75 μm) (Seika Beam (registered trademark) EXF-01B manufactured by Dainichi Seika Co., Ltd.) is applied so that the film thickness after drying is 5 μm, the solvent is dried, and then irradiated with ultraviolet light at 800 mJ / cm ² with a high-pressure mercury lamp. A laminate (1) in which a hard coat layer was laminated was obtained.

(8) Production of a conductive laminate (2) in which a transparent conductive layer is laminated on a transparent substrate Polyester film (Cosmo Shine (registered trademark) A4100; manufactured by Toyobo Co., Ltd .; 75 μm) is treated with argon on the non-adhesion treated surface. In an atmosphere of 0.533 Pa (4 × 10 ⁻³ Torr) composed of 80% by volume of gas and 20% by volume of oxygen gas, indium oxide having a thickness of 400 mm and oxidized by a reactive sputtering method using an indium-tin alloy. A transparent conductive layer made of a complex oxide with tin was formed to obtain a transparent conductive laminate (2).

(9) Production of upper electrode for touch panel The separate film on the acrylic pressure-sensitive adhesive layer side of the double-sided pressure-sensitive adhesive sheet obtained above was peeled off and adhered to the opposite surface of the transparent conductive layer of the transparent conductive laminate (2). . Next, the separate film on the silicone rubber pressure-sensitive adhesive layer side was peeled off and attached to the opposite surface of the hard coat layer of the laminate (1) to obtain an upper electrode for a touch panel. The workability in these sticking steps was good. In addition, since the silicone rubber adhesive layer is excellent in repairability, it could be easily repaired even if a sticking error occurred. Therefore, it was possible to eliminate the occurrence of defective products due to a sticking mistake.

  A pen sliding durability test was performed by the following method using the upper electrode for the touch panel. That is, the two upper electrodes are arranged opposite to each other so that the transparent conductive layers face each other through a spacer having a thickness of 100 μm, and a load of 5.0 N is applied to a polyacetal pen (tip shape: 0.8 mmR). A linear sliding test was conducted 100,000 times (50,000 reciprocations) at 23 ° C. and 44% RH. The sliding distance at this time was 30 mm, and the sliding speed was 60 mm / second.

  After this sliding durability test, first, when the sliding portion was whitened by visual observation, no whitening was observed in the electrode. Moreover, when the ON resistance (resistance value when the upper and lower electrodes are in contact) when the sliding portion is pressed with a pen load of 0.5 N was measured, it was kept within three times the initial value. It was confirmed that the dynamic durability was excellent.

Comparative Example 1
The laminate (1) and the transparent conductive laminate (2) produced in Example 1 were not laminated with a double-sided pressure-sensitive adhesive sheet, except that the laminate (1) and the transparent conductive laminate (2) were simply overlapped. When a pen sliding durability test was performed in the same manner as in Example 1, whitening was observed at the sliding portion. Further, the ON resistance was 15 times the initial value, and it was found that the pen sliding durability was inferior.

Comparative Example 2
In the method of Example 1, a double-sided pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the application of the coating solution for forming an adhesion improving layer (No. 1) was stopped, and an upper electrode for a touch panel was obtained. Table 1 shows the evaluation results of the double-sided PSA sheet. The double-sided pressure-sensitive adhesive sheet obtained in Comparative Example 2 was poor in the adhesiveness between the silicone rubber pressure-sensitive adhesive layer and the polyester-based substrate film substrate and the hot-water resistant adhesiveness, and thus was of low quality.

  When the pen sliding durability test of the upper electrode for the touch panel was conducted, no whitening was observed in the sliding part at 23 ° C. and 44% RH, but whitening was observed in the sliding part at 50 ° C. and 65% RH. Admitted. Further, the ON resistance was kept within 3 times the initial value at 23 ° C. and 44% RH, but was 6 times the initial value at 50 ° C. and 65% RH. In the double-sided pressure-sensitive adhesive sheet, the result reflected that the heat-resistant water adhesion was poor.

Comparative Example 3
In the method of Example 1, a double-sided PSA sheet was obtained in the same manner as in Example 1 except that the thickness of the adhesion improving layer was changed to 0.7 μm to obtain an upper electrode for a touch panel. Table 1 shows the evaluation results of the double-sided PSA sheet. The double-sided PSA sheet obtained in Comparative Example 3 was inferior in heat-resistant water adhesion and was of low quality. When the upper electrode for a touch panel was evaluated, the same result as in Comparative Example 2 was obtained.

Comparative Example 4
A double-sided pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the method for preparing the silicone rubber pressure-sensitive adhesive layer-forming coating solution was changed as described below to obtain an upper electrode for a touch panel. Table 1 shows the evaluation results of the double-sided PSA sheet.

[Preparation of silicone rubber adhesive layer forming coating solution]
High transparency silicone rubber compound ("TSE260-3U"; rubber hardness 30 degrees) consisting of 60 parts of a polydimethylsiloxane skeleton silicone compound, 25 parts of a polydimethylalkenylsiloxane skeleton silicone compound and 15 parts of silica; Momentive Performance Materials (Made by Japan) was weighed so that the mass ratio with respect to toluene might be 23%, and it poured into the stirrer with a vacuum degassing apparatus with toluene, and it stirred at room temperature for 15 hours under atmospheric pressure, and was dissolved in toluene. To the obtained solution, trimethylolpropane trimethacrylate was added so as to be 2 parts with respect to 100 parts of the rubber compound, and after stirring uniformly, the vacuum deaerator was driven and the gauge pressure was -750 mmHg. The mixture was further stirred for 20 minutes and degassed. In addition, the said silicone rubber compound used what passed 6 months after purchase. The obtained coating liquid was inferior in clarity and storage stability.

  Moreover, the double-sided pressure-sensitive adhesive sheet obtained in the present Comparative Example 4 was inferior in heat-resistant water adhesion and was of low quality. When the upper electrode for a touch panel was evaluated, the same result as in Comparative Example 2 was obtained.

Example 2
A polyester base film was obtained in the same manner as in Example 1 except that the application of the coating liquid (No. 1) was stopped during the production of the polyester base film of Example 1. Corona treatment was performed on both surfaces of this base film. Separately, a copolymerized polyester resin solution (“Byron (registered trademark) 30SS”; manufactured by Toyobo Co., Ltd.) and a polyisocyanate-based crosslinking agent (“Coronate (registered trademark) HX”; manufactured by Nippon Polyurethane Co., Ltd.) 100: 3 (part) was blended to prepare an adhesive improvement layer coating solution (No. 2). This adhesion improving layer coating solution (No. 2) was applied to both surfaces of the base film after the corona treatment using a coater and dried. The thickness of the adhesion improving layer was 0.31 μm on both sides.

  Thereafter, a double-sided PSA sheet was obtained in the same manner as in Example 1 to produce an upper electrode for a touch panel. Table 1 shows the evaluation results of the double-sided PSA sheet.

  The double-sided PSA sheet and touch panel upper electrode obtained in Example 2 had the same characteristics as the double-sided PSA sheet and touch panel upper electrode obtained in Example 1, and were of high quality.

Comparative Example 5
In preparation of the coating liquid for adhesion improving layer (No. 2) of Example 2, the formulation of “Coronate HX” as a cross-linking agent was stopped and only “Byron 30SS” was used. Thus, a double-sided pressure-sensitive adhesive sheet and an upper electrode for a touch panel were obtained. Table 1 shows the evaluation results of the double-sided PSA sheet.

  The double-sided PSA sheet obtained in Comparative Example 5 was inferior in heat-resistant water adhesion and was of low quality. When the upper electrode for a touch panel was evaluated, the same result as in Comparative Example 2 was obtained.

Examples 3-5
A double-sided PSA sheet was obtained in the same manner as in Example 1 except that the following coating solution was used instead of the coating solution (No. 1) for the adhesion improving layer of Example 1, and an upper electrode for a touch panel was produced. did. Table 2 shows the evaluation results of the double-sided PSA sheet.

  The double-sided pressure-sensitive adhesive sheet and touch panel upper electrode obtained in these examples had the same characteristics as the double-sided pressure-sensitive adhesive sheet and touch panel upper electrode obtained in Example 1, and were of high quality.

[Coating Solution for Adhesiveness Improvement Layer of Example 3]
10 parts of the “Cymel 303” and 0.04 part of the “Catalyst 600” with respect to 100 parts of the solid content of the acrylic emulsion (“Joncrill (registered trademark) PDX-7630A”; manufactured by BASF Japan). Were mixed to obtain a coating solution (No. 3) for an adhesion improving layer.

[Coating Solution for Adhesiveness Improvement Layer of Example 4]
As an oxazoline-based cross-linking agent ("Epocross (registered trademark) WS-700"; Nippon Shokubai Co., Ltd.) with respect to 100 parts of a solid content of a polyurethane-based aqueous dispersion ("Hydran (registered trademark) AP40"; manufactured by Dainippon Ink and Industry). Product) was added in solids to give a coating solution (No. 4) for an adhesion improving layer.

[Coating Solution for Adhesiveness Improvement Layer of Example 5]
40 parts of a self-crosslinking polyester resin aqueous dispersion “Vylonal (registered trademark) AGN702” (manufactured by Toyobo Co., Ltd.), 24 parts of water and 36 parts of isopropyl alcohol are mixed, and a 10% aqueous solution of an anionic surfactant 0.6 Part, propionate 1 part, colloidal silica particles (average particle size 40 nm) 20% aqueous dispersion 1.8 parts, dry process silica particles (average particle size 200 nm; average primary particle size 40 nm) 4% aqueous dispersion 1 .1 part was added, and it was set as the coating liquid (No. 5) for adhesive improvement layers.

Example 6
In the same manner as in Example 1, a laminate (i), a separate film, and a silicone compound solution were prepared. The silicone compound was applied to both sides of the laminate (i) so that the thickness after drying was 25 μm, and then introduced into an oven and dried at 80 ° C. A laminate (v) in which uncrosslinked silicone rubber adhesive layers were formed on both sides of the laminate (i) was obtained. While laminating separate films on the surfaces of the uncrosslinked adhesive layers on both sides of the laminate (v), the laminate (v) was pressed with a pressure roller (pressure 30 N / cm ² ) and continuously laminated. The obtained laminate (vi) is continuously introduced into an electron beam irradiation apparatus, and the first adhesive layer is crosslinked by irradiating an electron beam with energy of 200 KV and 16 Mrad from one side of the separate film side to form a roll. Rolled up. While feeding the sheet from the roll, it is continuously introduced again into the electron beam irradiation apparatus, and the second adhesive layer is crosslinked by irradiating the electron beam with energy of 200 KV and 18 Mrad from the other side of the separate film side. The obtained double-sided PSA sheet was wound into a roll. In the manufacturing process so far, the occurrence of the channeling phenomenon of the separate film was not observed. Thereafter, in the same manner as in Example 1, an upper electrode for a touch panel was obtained. Table 2 shows the evaluation results of the double-sided PSA sheet.

  The double-sided pressure-sensitive adhesive sheet and touch panel upper electrode obtained in Example 6 had the same characteristics as the double-sided pressure-sensitive adhesive sheet and touch panel upper electrode obtained in Example 1, and were of high quality.

Reference example 1
The peel strength of the silicone rubber pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet obtained in Example 1 and the separate film adhered to the rubber pressure-sensitive adhesive layer was measured by the following method.

[Measurement method of peel strength]
About the double-sided pressure-sensitive adhesive sheet having a length of about 200 mm and a width of 20 mm, the surface (2 surfaces) whose peelability is to be evaluated is exposed, and the double-sided pressure-sensitive adhesive sheet is divided into a laminate including one surface and a laminate including the other surface, Set each on the chuck of the tensile tester. That is, when measuring the peel strength at the interface between the release layer of the separate film and the silicone rubber pressure-sensitive adhesive layer, the double-sided pressure-sensitive adhesive sheet is peeled off a little at the interface between the release layer and the pressure-sensitive adhesive layer. Expose. A separate film is held by one chuck, and a double-sided adhesive sheet (preferably a separate film is preferably attached to the second adhesive surface) is held by one chuck. And T-type peeling strength was measured by the method as described in JIS K6854-3. The tensile tester used was a trade name “Autograph” (manufactured by Shimadzu Corporation), and a T-type peel test was performed under conditions of a distance between chucks of 50 mm, a temperature of 23 ° C., and a tensile speed of 200 mm / min. During peeling, the end of the film was lifted with a bar so that the T-shape was maintained. The maximum strength at the time of T-type peeling was defined as the peeling strength. The peel strength of Example 1 was 0.1 N / 20 mm.

Comparative Reference Example 1
In the method of Example 1, a double-sided pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the combination of the polymer wax component and the antistatic agent in the release layer forming coating solution was stopped. An attempt was made to peel the separate film from the silicone rubber pressure-sensitive adhesive layer of this double-sided pressure-sensitive adhesive sheet, but it could not be peeled. Therefore, the production of the upper electrode for the touch panel was discontinued.

  In the upper electrode for a touch panel of the present invention, a double-sided pressure-sensitive adhesive sheet having a silicone rubber pressure-sensitive adhesive layer having both sticking property and removability is used. The sheet can be removed and re-applied. In addition, since the silicone rubber pressure-sensitive adhesive layer has good elasticity, the touch panel can be given good cushioning properties, so that the pen sliding durability of the touch panel can be improved.

  Furthermore, the double-sided pressure-sensitive adhesive sheet used for the upper electrode for a touch panel of the present invention has excellent adhesion durability between the pressure-sensitive adhesive layer and the base polyester film, and is suitable even when used under harsh conditions. Can be used. In addition, the peeling force between the separate film and the silicone rubber pressure-sensitive adhesive layer laminated before use of the double-sided pressure-sensitive adhesive sheet is controlled to an appropriate range, and in the process of winding the double-sided pressure-sensitive adhesive sheet, the above-mentioned channeling phenomenon Since generation | occurrence | production is suppressed, a high quality double-sided adhesive sheet can be produced stably. Moreover, the workability | operativity at the time of incorporating a double-sided adhesive sheet in the upper electrode for touchscreens is also excellent.

  Therefore, a high-performance touch panel can be provided by using the upper electrode for a touch panel of the present invention.

Claims (8)

A laminate (1) having a configuration in which a hard coat layer is laminated on a transparent substrate and a conductive laminate (2) in which a transparent conductive layer is laminated on a transparent substrate are bonded with a double-sided PSA sheet. There, the double-sided pressure-sensitive adhesive sheet has at least one surface adhesion improving layer and the silicone rubber adhesive layer polyester base film in this order, said silicone rubber adhesive layer when evaluating the hot water resistance adhesive property by the following method The adhesion improving layer does not peel from the polyester base film , and includes a reaction product of one or more kinds of polymers selected from the group consisting of polyester, polyurethane and acrylic polymers, and a crosslinking agent, The release layer of the separate film laminated on the silicone rubber adhesive layer surface before using the double-sided adhesive sheet is a non-silicone compound, binder resin, polymer Box component and the upper electrode for a touch panel, wherein a layer containing an antistatic agent.
Evaluation method of hot water adhesion
Cut the double-sided PSA sheet to 50mm x 50mm, peel off the separate film, and place the sample in the 500cc lidded cylindrical glass container with distilled water 400cc so that the silicone rubber adhesive layer is on the bottom The container is covered with the sample immersed in water. Place the container with the sample in a gear oven set at 80 ° C. and let it stand for 24 hours. Then, remove the container from the oven, quickly remove the sample, and use your finger pad from the silicone rubber adhesive layer side to the end. Applying force and rubbing 10 times, it is evaluated whether or not the adhesive layer peels from the polyester base film side. Upper electrode for a touch panel according to claim 1 a thickness of the adhesion improving layer is 0.01~0.5μ m. The silicone rubber adhesive layer, polydimethylsiloxanes upper electrode for a touch panel according to claim 1 or 2 contains a crosslinked silicone compound having a skeleton. The upper electrode for a touch panel according to claim 3 , wherein the crosslinked silicone compound is obtained by crosslinking an uncrosslinked body of a silicone compound having a polydimethylsiloxane skeleton having a number average molecular weight of 50,000 to 500,000. The upper electrode for a touch panel according to any one of claims 1 to 4 , wherein the double-sided pressure-sensitive adhesive sheet has a silicone rubber pressure-sensitive adhesive layer and an acrylic pressure-sensitive adhesive layer. The upper electrode for a touch panel according to any one of claims 1 to 4 , wherein the adhesive layer of the double-sided adhesive sheet is a silicone rubber adhesive layer on both sides. After peeling the cell Pareto film laminated to sheet silicone rubbers adhesive layer surface before use of the double-sided pressure-sensitive adhesive sheet, which is formed by bonding the laminate (1) above electroconductive laminate and (2) The upper electrode for a touch panel according to any one of claims 1 to 6 . The upper electrode for a touch panel according to any one of claims 1 to 7 , wherein the peel strength between the separate film and the silicone rubber adhesive layer measured by the following method is 0.03 to 1.0 N / 20 mm.
Measuring method of peel strength
For a double-sided PSA sheet with a length of about 200 mm and a width of 20 mm in which the separate films are laminated, the double-sided PSA sheet is peeled off slightly at the interface between the silicone rubber adhesive layer and the release layer of the separate film, and one chuck of the tensile tester is used. Then, a separate film composed of a release layer and a polyester film is held, and a double-sided adhesive sheet is held with the other chuck. A T-type peel test is performed under conditions of a distance between chucks of 50 mm, a temperature of 23 ° C., and a tensile speed of 200 mm / min, and the maximum strength at the time of T-type peel is defined as the peel strength.