JP2015091646A - Mold release film, and substrate-less double-sided adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-quality mold release film which is necessary to a member for electrostatic capacitance type touch panels or a flat panel substrate, is used particularly for a foreign matter-avoiding highly-transparent substrate-less double-sided adhesive sheet, is used more particularly under spatter-scattered high temperature conditions, prevents contamination of a process severe in a clean degree when processed therein, and has excellent foreign matter inspectability.SOLUTION: The mold release film is obtained by: applying a coating liquid, which contains a quaternary ammonium base-containing polymer, a polyethylene glycol-containing acrylate polymer and a crosslinking agent, to at least one surface of a base material polyester film to form a first coated layer; applying a coating agent containing at least one organosiloxane compound onto at least one first coated layer to form a second coated layer having 10-100 nm thickness; and further forming such a mold release layer on at least one second coated layer that the amount of the oligomer to be deposited on the film surface is 0.5 mg/mor smaller when the surface of the mold release layer is heat-treated at 150°C for 60 minutes.

Description

  The present invention relates to a release film and a substrate-less double-sided pressure-sensitive adhesive sheet, and relates to a release film having excellent oligomer sealing performance and foreign matter inspection performance and a substrate-less double-sided pressure-sensitive adhesive sheet having the release film.

  Conventionally, various pressure-sensitive adhesive sheets for surface bonding between objects are known, and a base-less double-sided pressure-sensitive adhesive sheet is known as one of pressure-sensitive adhesive sheets. The substrate-less double-sided PSA sheet consists of a laminate structure in which a light release film with a relatively low peel strength and a heavy release film with a relatively high peel strength are laminated on both sides of the adhesive layer. After the removal, the double-sided pressure-sensitive adhesive sheet becomes only the pressure-sensitive adhesive layer having no supporting substrate.

  As a method of using the base material-less double-sided pressure-sensitive adhesive sheet, first, the light release film is peeled off, and one surface of the exposed pressure-sensitive adhesive layer is bonded to the object surface of the other side to be bonded. A processing step in which the other surface of the exposed pressure-sensitive adhesive layer is bonded to different object surfaces and thereby the surfaces are bonded to each other is exemplified (Patent Document 1).

  In recent years, the baseless double-sided pressure-sensitive adhesive sheet has attracted attention because of its good workability, and its application is expanding. It is also used for members for various optical applications such as mobile phones and tablet computers. In particular, a capacitive touch panel is rapidly expanding its application as an information terminal by a multi-touch operation in which a screen operation is performed with two fingers.

  In such applications, fine foreign objects that could not be seen in the past have been discovered by recent technological developments in base materials and light sources (LEDs, etc.) It is supposed to be. Therefore, when using a baseless double-sided PSA sheet for optical applications, not only the baseless double-sided PSA sheet but also the release film to be combined are more severe than ever before, as a countermeasure for the generation of foreign substances and prevention of outflow. Is required, and a release film of higher quality is required.

  In addition, in a conventional release film, in particular, a release tellurium film using a polyester film as a base material, a polyester film base material component (here, an oligomer is shown, and hereinafter abbreviated as OL) is obtained by heating during the process. Occurs). This OL becomes a foreign substance, which may reduce the quality yield.

  As a countermeasure against the above-mentioned foreign matter generation source, there is one technique for suppressing the generation of OL in this release film. Examples of the existing technology include a method using a polyester raw material with a small amount of OL, a method of providing an OL sealing layer (Patent Documents 1 and 3), and a method of combining the two technologies. However, in the former case, the efficacy may be insufficient, and in the latter case, there is a problem that the silicone film cannot be formed well during the final silicone processing due to a small amount of transfer of the components of the OL sealing layer. That is, in the release film technology, there is a demand for OL sealing layer application technology for stably coating the silicone release layer.

  As a measure for preventing the outflow of foreign matter, there is a case where an inspection with optical evaluation is carried out by bonding to a counterpart member with an adhesive layer provided on the second release film (heavy release side). In that case, when an inspection is performed through an optical member having a polarizing action, the inspection visual field may become dark depending on the angle. Moreover, in the optical visual evaluation in the state which bonded the release film, the granular feeling resulting from the particle | grains of a release film may interfere with visual inspection.

Japanese Patent No. 5281595 Published Japanese Patent Application No. 2011-223513 JP 2012-179870 published

  This invention is made | formed in view of the said situation, Comprising: The solution subject is a release film required for the member for electrostatic capacitance type touch panels, and a flat panel base material, and is especially highly transparent which dislikes a foreign material. Substrate-less double-sided pressure-sensitive adhesive sheet, especially used under high-temperature conditions with spattering, and prevents high-quality separation that prevents contamination of processes with severe cleanliness during processing and has excellent foreign matter inspection. It is to provide a mold film.

  As a result of intensive studies, the present inventor has found that the above problem can be easily solved by a release film having a specific configuration, and has completed the present invention.

That is, the gist of the present invention is that a base polyester film has a first coating layer obtained by coating a coating solution containing a quaternary ammonium base-containing polymer, a polyethylene glycol-containing acrylate polymer and a crosslinking agent on at least one surface. And having a second coating layer formed by coating a coating agent containing at least one organosiloxane compound on at least one first coating layer and having a thickness of 10 to 100 nm, and at least one first coating layer. 2 A release layer having a release layer on the coating layer, and the amount of oligomer deposition on the film surface after heat-treating the release layer surface at 150 ° C. for 60 minutes is 0.5 mg / m ² or less Be on film.

  According to the present invention, the substrate-less double-sided pressure-sensitive adhesive sheet necessary for mobile and television applications, for example, capacitive touch panel members and flat panel substrates, particularly used under high-temperature conditions involving sputtering. The release film used for the base material-less double-sided pressure-sensitive adhesive sheet can be provided with a high-quality release film having a high OL sealing function and excellent in foreign matter inspection. Industrial value is high.

Schematic explanatory drawing showing the configuration of the release film of the present invention Schematic explanatory drawing showing the configuration of the substrate-less double-sided PSA sheet of the present invention Schematic explanatory drawing which shows the structure of the transparent conductive film member provided with the base-material-less double-sided adhesive sheet of this invention

  The base polyester film used in the release film of the present invention is a polyester film extruded by a so-called extrusion method that is melt-extruded from an extrusion die, and, if necessary, in the biaxial direction of the longitudinal direction and the lateral direction. An oriented film.

  The polyester is obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), and the like.

  Further, the above polyester may be a homopolyester or a copolyester. In the case of a copolyester, it is a copolymer containing 30 mol% or less of the third component. Examples of the dicarboxylic acid component of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acids (for example, P-oxybenzoic acid). Or 2 or more types are mentioned, As a glycol component, 1 type, or 2 or more types, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanol, neopentyl glycol, are mentioned.

  The base polyester film is a laminated polyester film having a polyester layer containing 3000 to 30000 ppm of a polymer containing at least two epoxy groups in the molecular chain on both surfaces in order to further enhance the OL sealing function. May be. When the content of the epoxy group is less than 3000 ppm, the acid catalyst deactivation ability of the carboxyl group due to the epoxy group is not sufficient, and when the content exceeds 30000 ppm, the viscosity of the polyester is increased by cross-linking by a chemical reaction between the epoxy group and the carboxyl group. As a result, it becomes difficult to extrude with a polyester extruder.

  The type of the polymer having at least two epoxy groups in the molecular chain is not particularly limited as long as it is a polymer compatible with the polyester resin. For example, polyester resin, acrylic resin, polyurethane resin, polycarbonate resin, styrene Resin, polyimide resin, polyamide resin, polyolefin resin, a mixture thereof, a copolymer, and the like. A resin that is particularly preferably used is a copolymer of an acrylic resin and a styrene resin.

  The molecular weight of the polymer having at least two epoxy groups in the molecular chain is not particularly limited as long as it is compatible with the polyester resin, but the average molar molecular weight is usually 350 to 8000 g / mol, preferably 400 to 3000 g. / Mol, more preferably 500 to 3000 g / mol.

  The thickness of the polyester film for OL sealing function is usually 2 μm or more, preferably 4 μm or more, more preferably 5 μm or more, and particularly preferably 6 μm or more. When the thickness is less than 4 μm, the OL sealing function tends not to be sufficiently exhibited.

  In the base polyester film, it is preferable to blend particles mainly for the purpose of imparting slipperiness and preventing the occurrence of scratches in each step. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples of the particles include magnesium, kaolin, aluminum oxide, and titanium oxide. Further, heat-resistant organic particles as described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used.

  On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

  Moreover, the average particle diameter of the particle | grains to be used is 0.01-3 micrometers normally, Preferably it is the range of 0.1-2 micrometers. When the average particle size is less than 0.01 μm, the slipperiness may not be sufficiently imparted. On the other hand, when the thickness exceeds 3 μm, transparency may be lowered due to an aggregate of the particles during film formation, and breakage is likely to occur, resulting in a problem in productivity.

  Further, the base polyester film may be a laminated polyester film having polyester layers containing core-shell type particles having an average particle diameter of 0.5 to 3.0 μm on both surfaces in order to improve visibility. Good. The advantage of using the core-shell type organic particles is the resin followability when the polyester film is stretched. Specifically, in the film-forming process that imparts easy testability to the polyester film, a special stretching prescription that increases the stretching ratio in the running direction of the film or in the direction perpendicular to the running direction may be used. Occasionally, ordinary inorganic particles and simple organic particles cannot follow the stretching of the polyester and generate voids. This void causes light to be refracted and scattered, and gives a grainy appearance by visual inspection. In the core-shell type organic particles, the outer shell and the inner core molecular weight, crosslink density, hardness can be adjusted as appropriate, and by adjusting the above, the occurrence of voids is prevented, and the graininess is eliminated. Foreign objects can be found more clearly.

  On the other hand, the shape of the core / shell type organic particles to be used is not particularly limited, and any shape such as a spherical shape, a lump shape, a rod shape, a flat shape, etc. can be used as long as the resin following property is prevented so as to prevent the generation of voids. Also good. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

  The average particle size of the core-shell type organic particles used is usually in the range of 0.5 to 3.0 μm, preferably 1.0 to 2.0 μm. When the average particle size is less than 0.5 μm, sufficient slipperiness cannot be imparted, and haze is increased in order to provide sufficient slipperiness. On the other hand, when the thickness exceeds 3.0 μm, the transparency may be lowered due to the aggregate of the particles during film formation, and it is easy to cause breakage, which is a problem in terms of productivity. Become.

  Furthermore, the particle content in the base polyester film (single layer polyester film or laminated polyester film) is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. When the particle content is less than 0.001% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 5% by weight, the transparency of the film is insufficient. There is a case.

  The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage for producing the polyester constituting each layer, but it is preferably added after completion of esterification or transesterification.

  Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a blending of dried particles and a polyester raw material using a kneading extruder. It is done by methods.

  In addition, in the release film substrate, conventionally known antioxidants, antistatic agents, thermal stabilizers as necessary, in addition to the above particles, as long as they do not affect the inhibition of the curing reaction to the silicone release layer , Lubricants, dyes, pigments and the like can be added.

  Next, although the manufacture example of a polyester film is demonstrated concretely, it is not limited to the following manufacture examples at all. That is, a method of using the polyester raw material described above and cooling and solidifying a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method is preferably employed. Next, the obtained unstretched sheet is stretched in the biaxial direction. In that case, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7.0 times, preferably 3.0 to 6.0 times. Next, the film is stretched in the direction perpendicular to the first stretching direction. In that case, the stretching temperature is usually 70 to 170 ° C., and the stretching ratio is usually 3.0 to 7.0 times, preferably 3.5 to 6 times. .0 times. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  For the production of the polyester film, a simultaneous biaxial stretching method can also be employed. The simultaneous biaxial stretching method is a method in which the above-mentioned unstretched sheet is usually stretched and oriented in the machine direction and the width direction at a temperature controlled normally at 70 to 120 ° C., preferably 80 to 110 ° C. Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in terms of area magnification. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, a conventionally known stretching method such as a screw method, a pantograph method, or a linear driving method can be employed.

  The thickness of the release film of the present invention is preferably within a range that does not reduce the yield during film formation and the yield during functional coating processing, and further, the stiffness in the subsequent adhesive process is not guaranteed. Must not. Usually, it is 150 micrometers or less, Preferably it is 25-150 micrometers, More preferably, it is the range of 38-150 micrometers. If the film thickness is less than 25 μm, the stiffness in the pressure-sensitive adhesive process is not ensured, and there is a problem that the workability is deteriorated. Processing of the agent becomes difficult, and problems such as not being able to wind a lot in the adhesive process occur.

  Next, formation of the 1st application layer (it is a layer adjacent to a polyester base material) which comprises the release film of this invention is demonstrated. Regarding the first coating layer, it may be provided by in-line coating, which treats the film surface during the stretching process of the polyester film, or may be applied off-system on the film once manufactured, and may be adopted off-line coating. May be used in combination. Since coating can be performed simultaneously with film formation, in-line coating is preferably used in that the production can be handled at low cost and the thickness of the first coating layer can be changed by the draw ratio.

  The in-line coating is not limited to the following, but for example, in the sequential biaxial stretching, the coating treatment can be performed particularly before the lateral stretching after the longitudinal stretching is finished. When a coating layer is provided on a polyester film by in-line coating, coating can be performed simultaneously with film formation, and the coating layer can be processed at a high temperature, and a film suitable as a polyester film can be produced.

  The first coating layer has an essential requirement to use a coating solution containing a quaternary ammonium base-containing polymer for the purpose of preventing oligomer components from entering the process and preventing contamination.

  Regarding the quaternary ammonium base-containing polymer, a polymer having a constituent element containing a quaternary ammonium base in the main chain or side chain in the molecule is an object. Specific examples include pyrrolidinium ring, quaternized alkylamine, copolymerized with acrylic acid or methacrylic acid, quaternized N-alkylaminoacrylamide, vinylbenzyltrimethylammonium salt, 2-hydroxy-3- And methacryloxypropyltrimethylammonium salt. Furthermore, these may be combined or copolymerized with other binder polymers. Examples of the anion that serves as a counter ion for these quaternary ammonium salts include ions such as halogen, alkyl sulfate, alkyl sulfonate, and nitric acid. Among these, counter ions other than halogen are preferable for the use of the present invention in that heat resistance is particularly good.

  Further, regarding the molecular weight of the quaternary ammonium base-containing polymer, if the molecular weight is too low, it may be easily removed from the coating layer and the performance may deteriorate over time, or problems such as blocking of the coating layer may occur. Moreover, when the molecular weight is low, the heat stability tends to be inferior.

  From this viewpoint, the number average molecular weight of the quaternary ammonium base-containing polymer is usually 1000 or more, preferably 2000 or more, and more preferably 5000 or more. On the other hand, when the number average molecular weight is too high, problems such as excessive increase in the viscosity of the coating solution may occur. Therefore, the upper limit of the number average molecular weight is preferably 500,000 or less. Moreover, these compounds may be used independently and may be used in combination of 2 or more types.

  The blending amount of the quaternary ammonium base-containing polymer in the first coating layer is preferably in the range of 20 to 70% by weight, more preferably in the range of 40 to 70% by weight in terms of dry weight. When it is out of the range, it becomes difficult to obtain a desired OL sealing effect.

  In the present invention, it is essential to contain a polyethylene glycol-containing acrylate polymer in the coating solution for the purpose of improving the stretch following property at the time of forming the first coating layer. Specifically, polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, polyethylene glycol diacrylate (the polymerization degree of polyethylene glycol units is preferably in the range of 4 to 14), polypropylene glycol diacrylate, polytetramethylene glycol diacrylate, poly ( Ethylene glycol-tetramethylene glycol) diacrylate, poly (propylene glycol-tetramethylene glycol) diacrylate, polyethylene glycol-polypropylene glycol-polyethylene glycol diacrylate, polypropylene glycol-polybutylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate, methoxypolyethylene Glycol monoacrelan , Octoxy polyethylene glycol-polypropylene glycol monomethacrylate, Octoxy polyethylene glycol-polypropylene glycol monoacrylate, Lauroxy polyethylene glycol monomethacrylate, Lauroxy polyethylene glycol monoacrylate, Stearoxy polyethylene glycol monomethacrylate, Stearoxy polyethylene glycol monoacrylate, Ali Examples include polymers starting from loxypolyethylene glycol monomethacrylate, allyloxypolyethylene glycol monoacrylate, and the like.

  The number average molecular weight of the polyethylene glycol-containing acrylate polymer is usually 1000 or more, preferably 2000 or more, and more preferably 5000 or more. On the other hand, when the number average molecular weight is too high, problems such as the viscosity of the coating solution becoming too high may occur. From this point of view, the upper limit of the number average molecular weight is preferably 500,000 or less. Moreover, these compounds may be used independently and may be used in combination of 2 or more types.

  In the present invention, a polyethylene glycol-containing alkyl acrylate polymer is preferably used in combination in order to further improve stretchability. The chain length of the alkyl chain is not particularly limited as long as it is in a range that can be polymerized as a polymer. The content of the polyethylene glycol-containing alkyl acrylate polymer is preferably in the range of 5 to 40% by weight in order to improve stretchability. When it is out of the range, problems such as insufficient stretch followability at the time of forming the first coating layer occur.

  The quaternary ammonium base-containing polymer and the polyethylene glycol-containing acrylate polymer may be a mixture or may be copolymerized in advance, and are not particularly limited as long as the gist of the present invention is not impaired. . Moreover, when making it copolymerize, a conventionally well-known manufacturing method can be used.

  In the present invention, it is necessary to use a crosslinking agent in combination as a coating solution for the purpose of further improving the durability of the first coating layer. Specific examples include methylolated or alkylolized urea, melamine, guanamine, oxazoline, epoxy compound, acrylamide, polyamide compound, epoxy compound, aziridine compound, isocyanate compound, titanium coupling agent, zirco-aluminate coupling agent, poly Examples thereof include carbodiimide.

  Among the cross-linking agents, melamine cross-linking agents are preferable in terms of good coating properties and durable adhesion particularly in the use of the present invention. The melamine crosslinking agent is not particularly limited, but melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, a compound partially or completely etherified by reacting methylolated melamine with a lower alcohol, And a mixture thereof can be used.

  The melamine crosslinking agent may be either a monomer or a condensate composed of a dimer or higher multimer, or a mixture thereof. As the lower alcohol used for the etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like can be preferably used. The functional group has an imino group, a methylol group, or an alkoxymethyl group such as a methoxymethyl group or a butoxymethyl group in one molecule, and an imino group type methylated melamine, a methylol group type melamine, or a methylol group type methylation. Melamine, fully alkyl methylated melamine and the like can be used. Of these, methylolated melamine is most preferred. Furthermore, for the purpose of promoting thermal curing of the melamine crosslinking agent, for example, an acidic catalyst such as p-toluenesulfonic acid can be used in combination.

  The oxazoline crosslinking agent is a compound having an oxazoline ring in the molecule, and includes a monomer having an oxazoline ring and a polymer synthesized using an oxazoline compound as one of raw material monomers.

  Isocyanate compound refers to a compound having an isocyanate group in the molecule, specifically hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, naphthalene diisocyanate, tolylene diisocyanate, and the like. And polymers and derivatives thereof.

  As an epoxy compound, the compound containing an epoxy group in a molecule | numerator, its prepolymer, and hardened | cured material are mentioned, for example. A typical example is a condensate of epichlorohydrin and bisphenol A. In particular, a reaction product of a low molecular polyol with epichlorohydrin gives an epoxy resin having excellent water solubility.

  These cross-linking agents may be used alone or in combination of two or more. Furthermore, when consideration is given to application to in-line coating, it is preferable to have water solubility or water dispersibility.

  In the present invention, it is also possible to use a binder polymer in the coating layer as long as the gist of the present invention is not impaired.

  The “binder polymer” used in the present invention is a number average molecular weight (Mn) measured by gel permeation chromatography (GPC) according to a polymer compound safety evaluation flow scheme (sponsored by the Chemical Substance Council in November 1985). ) Is a polymer compound having a molecular weight of 1000 or more and having a film-forming property.

  Specific examples of the binder polymer include polyester resin, acrylic resin, polyvinyl (polyvinyl alcohol, polyvinyl chloride, vinyl chloride vinyl acetate copolymer, etc.), polyurethane resin, polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starch. And the like.

  Analysis of the components in the coating solution for forming the first coating layer can be performed by surface analysis such as TOF-SIMS.

  When the first coating layer is provided by in-line coating, the above-mentioned series of compounds is applied as an aqueous solution or water dispersion, and a coating solution adjusted to a solid content concentration of about 0.1 to 50% by weight as a guide is applied onto the polyester film. It is preferable to produce a laminated polyester film as described above. Moreover, in the range which does not impair the main point of this invention, a small amount of organic solvents may be contained in the coating liquid for the purpose of improving dispersibility in water, improving film-forming properties, and the like. Only one type of organic solvent may be used, or two or more types may be used as appropriate.

The film thickness of a 1st application layer is 0.02-0.10 g / m < ² > (namely, 20-100 nm) normally, More preferably, it is 0.03-0.08 g / m < ² >, More preferably, it is 0.04-0. The range is 0.07 g / m ² . When the film thickness is less than 0.02 g / m ^2, sufficient OL sealing performance cannot be obtained, and when it exceeds 0.1 g / m ² , the curing of silicone is severely inhibited, and a release coating film is not formed. In addition, the cost increases.

  Examples of the method for providing the first coating layer include conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, and curtain coating. Regarding the coating method, there is a description example in “Coating method” published by Yasuharu Harasaki in 1979.

  The drying and curing conditions for forming the first coating layer are not particularly limited. For example, when the coating layer is provided by off-line coating, it is usually 80 to 200 ° C. for 3 to 40 seconds, preferably 100. The heat treatment is preferably performed at ˜180 ° C. for 3 to 40 seconds as a guide.

  On the other hand, when providing a 1st application layer by in-line coating, it is good to heat-process normally for 3 to 200 second at 70-280 degreeC.

  Further, irrespective of off-line coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as required. The base polyester film in the present invention may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

  Next, formation of the 2nd application layer laminated | stacked on a 1st layer is demonstrated. Regarding the second coating layer, the above-described coating stretching method (in-line coating) may be used, or a so-called off-line coating applied outside the system on the polyester film having the coating layer once manufactured may be employed. Any method may be adopted.

The second coating layer is formed by coating a coating agent containing at least one organosiloxane compound. Urethane acrylic compounds may have an adverse effect when an acrylic molecular unit forms a release layer, but organosiloxane compounds do not have such problems. Examples of organosiloxane compounds are shown below. Various substituents of the organosiloxane of the following formula are variously changed.
_{^{(R 1) (R 3)}} 2 Si- (O-Si (R 1) (R 3)) n- (O-Si (R 2) (R 3)) m-R 3

In the above formula, R ¹ and R ² are each independently an organic group containing an epoxy group such as a γ-glycidoxypropyl group, a 3,4-epoxycyclohexylethyl group, or a methoxy group, ethoxy group R ³ is an alkoxy group such as a methoxy group or an ethoxy group, or a group represented by the following formula.

—O—Si (R ³ ) ₂ (R ⁴ )

In the above formula, R ⁴ is the same epoxy group-containing organic group or alkoxy group as the R ¹ group or R ² group. Specific examples of the organosiloxane include γ-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 5 , 6-epoxyhexyltriethoxysilane, tetraethoxysilane, metolaethoxysilane, and other monomers, and hydrolyzable organisms of these monomers or mixtures of these monomers.

  The organic solvent that dissolves the second coating layer forming material is preferably one containing at least one alcohol solvent selected from ethanol, propanol, i-propanol, butanol, i-butanol, t-butanol, pentanol and the like.

  Further, inorganic particles may be contained for the purpose of improving the adhesion and slipperiness of the second coating layer, and specific examples include silica, alumina, kaolin, calcium carbonate, titanium oxide, barium salt and the like.

  In addition, if the material has a low influence on the curing reaction inhibition of the release layer described later, an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an organic polymer particle, an antioxidant, if necessary. An agent, an ultraviolet absorbent foaming agent, a dye, and the like may be contained.

  In the range not exceeding the gist of the present invention, only one type of organic solvent may be used for the purpose of improving dispersibility, improving film forming property, etc., and two or more types may be used as appropriate.

  The coating amount (after drying) of the second coating layer is usually in the range of 10 to 100 nm, preferably 20 to 100 nm. When the coating amount is less than 10 nm, the uniformity of the coating thickness may be insufficient, and the amount of OL deposited from the surface of the B layer after heat treatment increases. On the other hand, if the thickness exceeds 100 nm, the coating film is brittle even if it has OL sealing performance, and scratches are likely to occur in the drying process and then the winding process after coating, and the film appearance tends to become cloudy.

  The roughness (Sa) of the second coating layer surface is preferably 10 nm or less. When the surface roughness exceeds 10 nm, the OL sealing performance tends to decrease. Furthermore, in order to exhibit sealing performance, Sa is preferably 8 nm or less. As a method of controlling this Sa, it is important that clusters (aggregates) are not generated as much as possible with the coating liquid before coating. As a result of the examination, it was found that the Sa can be controlled when the solution haze is usually 1.0% or less, preferably 0.5% or less.

  As a method for providing the second coating layer, a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating or the like can be used. As for the coating method, there is a description example in “Coating method” published by Yoji Harasaki in 1979.

  Regarding the curing conditions for forming the second coating layer, heat treatment is usually performed at 120 ° C. or higher, preferably 120 to 200 ° C. for 3 to 40 seconds, more preferably 120 to 160 ° C. for 3 to 40 seconds. Heat treatment is performed. When the heat treatment is not performed at 120 ° C. or higher, the coating film formation is incomplete and the amount of OL deposited increases.

  In the present invention, OL (oligomer) is defined as a cyclic trimer among low molecular weight substances that crystallize and precipitate on the film surface after heat treatment.

  In this invention, it is the 1st application layer and the 2nd application layer which have OL sealing performance independently, but by combining these, the structure which complements the adhesion | attachment interaction in a film | membrane and a mutual gap is taken. The OL sealing performance can be achieved more efficiently than making either one of the films with the same thickness (the thickness of the first coating layer + the second coating layer). Further, even if only the second coating layer is applied to a certain extent so as to exceed 100 nm, a desired OL sealing performance can be imparted. Cause inhibition of curing. Further, when the film thickness is large, the cost is also a big problem for production. The technical key of the present invention is that the combination of the first and second coating layer layers and the thickness are important, and it is considered that a synergistic effect is brought about in the OL sealing performance.

  The release layer provided on the coating layer (first coating layer) and (second coating layer) in the present invention is not particularly limited as long as it contains a material having releasability. Among them, the one containing a curable silicone resin is preferable because the releasability is improved. A type having a curable silicone resin as a main component may be used, or a modified silicone type by graft polymerization with an organic resin such as a urethane resin, an epoxy resin, or an alkyd resin may be used.

  As the type of the curable silicone resin, any of the curing reaction types such as an addition type, a condensation type, an ultraviolet ray curable type, an electron beam curable type, and a solventless type can be used.

  Specific examples of the curable silicone resin include KS-774, KS-775, KS-778, KS-779H, KS-847H, KS-856, X-62-2242, X-manufactured by Shin-Etsu Chemical Co., Ltd. 62-2461, X-62-1387, X-62-5039, X-62-5040, KNS-3051, X-62-1496, KNS320A, KNS316, X-62-1574A / B, X-62-7052, X-62-7028A / B, X-62-7619, X-62-7213, YSR-3022, TPR-6700, TPR-6720, TPR-6721, TPR6500, TPR6501, manufactured by Momentive Performance Materials, UV9300, UV9425 , XS56-A2775, XS56-A2982, UV9430, TP 6600, TPR6604, TPR6605, Toray Dow Corning Co., Ltd. SRX357, SRX211, SD7220, SD7292, LTC750A, LTC760A, LTC303E, LTC856, LTC855, LTC300, SP7259, BY24-468C, SP-4248S, BY Examples include DKQ3-203, DKQ3-204, DKQ3-205, and DKQ3-210. Further, a release control agent may be used in combination to adjust the release property of the release layer. Further, a release control agent may be used in combination to adjust the release property of the release layer. Further, as described above, a silane compound having an amino group may be added to the release layer.

As a method for providing the release layer, the coating amount of the release layer for which a conventionally known coating method such as reverse roll coating, gravure coating, bar coating, doctor blade coating or the like can be used is usually 0.01 to 1 g / it is in the range of m ^2.

  A coating layer such as an adhesive layer, an antistatic layer, and an oligomer precipitation preventing layer may be provided on the surface where the release layer is not provided, and the polyester film is subjected to a surface treatment such as corona treatment or plasma treatment. May be.

  Moreover, drying and / or curing (thermal curing, ionizing radiation curing, etc.) of the coating film of the pressure-sensitive adhesive layer or the release layer can be performed individually or simultaneously. When performing simultaneously, it is preferable to carry out at the temperature of 80 degreeC or more. The drying and curing conditions are preferably 80 ° C. or higher and 10 seconds or longer. If the drying temperature is less than 80 ° C. or the curing time is less than 10 seconds, the coating film is incompletely cured, and the coating film tends to fall off.

  In the present invention, it is preferable to use a transition metal catalyst in order to make the release film coating layer clean and strong. The transition metal catalyst content in the coating layer is in the range of 1.0 to 5.0% by weight, preferably 3.0 to 4.0% by weight. When the transition metal catalyst content in the coating layer is lower than 1.0% by weight, a component containing nitrogen or the like containing surplus electrons contained in the first and second coating layers installed for the purpose of OL sealing, Since the silicone curing reaction is inhibited, the adhesion of the coating film may be lowered, and the defect of peeling force and the curing reaction in the coating layer become insufficient, resulting in problems such as deterioration of the surface condition. In this invention, although it can achieve by adjusting the transition metal catalyst content in the said coating layer earnestly, it succeeded in improving coating-film adhesiveness as a synergistic effect. On the other hand, when the content of the transition metal catalyst in the coating layer exceeds 5.0% by weight, the cost may be increased, and the reactivity is increased and gel foreign matter is generated. Therefore, the pot life is remarkably increased. Process defects such as shortening occur.

  For the measurement of the content of the transition metal catalyst, the amount of metal in the coating layer was measured by a film FP method using a fluorescent X-ray analyzer (model “XRF-1500” manufactured by Shimadzu Corporation). The amount of elements in the film can be determined by measurement. The detection limit in this method is usually about 1 ppm. Alternatively, the sample film is obliquely cut using SAICAS to expose the cross section, and then the coating layer portion is coated with a polyester film using TOF-SIMS (time-of-flight mass spectrometry mass spectrum). The amount of catalyst containing a transition metal contained in the layer can be determined.

In the release film that was kept for 1 day after the preparation, 3 ml of 1-butanol solution in which 5% by weight of potassium hydroxide was dissolved in a vial (20 mL) was added in order to ensure the release stability over time. After immersing the mold film (40 cm ² ) and heat-treating the vial (20 mL) at 50 ° C. for 1 hour, the amount of hydrogen (H ₂ ) gas generated from the release film is preferably suppressed to 60 ppm or less, more preferably Is 40 ppm or less. When the amount of hydrogen (H ₂ ) gas generated from the release film exceeds 60 ppm, when the adhesive layer and the release layer of the release film are pasted together for a long period of time, the variation in peeling over time is large. In a scene that originally needs to be peeled off, problems such as difficulty in peeling occur.

In the release film, as a specific method for suppressing the hydrogen (H ₂ ) gas generation amount to 60 ppm or less, for example, a silicone resin with a small amount of functional groups is used for the purpose of adjusting the release of the release layer. In the case of using a peeling control agent in combination, a method of selecting a type having a small amount of Si—H group derived from the crosslinking agent is exemplified.

  Conventionally, a person skilled in the art commonly uses a method of adding a large amount of a crosslinking agent for the purpose of increasing the amount of Si-H groups derived from a crosslinking agent, as a method for increasing the peeling force. It is done. However, in this method, as the amount of Si—H groups derived from the crosslinking agent decreases with time due to the influence of moisture absorption or the like, the variation in peeling increases. For this reason, when the release film and the pressure-sensitive adhesive layer are stored in a state of being bonded together for a long time after the application of the pressure-sensitive adhesive, problems such as heavy release occur when the release film is peeled.

The release film of the present invention can be used even in applications involving sputtering of inorganic metal oxides such as highly transparent conductive substrates, and after the release layer surface of the release film is heat-treated (150 ° C., 60 minutes) , OL amounts extracted by dimethylformamide from the surface, is preferably 0.50 mg / ^{m 2} less, more preferably 0.20 mg / ^{m 2,} particularly preferably not more than 0.10 mg / ^{m 2.} When OL exceeds 0.50 mg / m ² , for example, in the sputtering process, OL occurs during heating due to scratches on the film attached with a roll or the like, and is temporarily attached to the final product after bonding. This may cause problems in the inspection process that involves a decrease in the transparency of the pressure-sensitive adhesive, a decrease in the adhesive strength of the pressure-sensitive adhesive layer, and optical evaluation, and further causes a process contamination.

The release film of the present invention can also be used in a normal pressure-sensitive adhesive process. The amount of OL extracted from the surface with dimethylformamide after heat treatment (180 ° C., 10 minutes) is performed on the release layer surface of the release film. , is preferably 0.20 mg / ^{m 2} or less, more preferably 0.15 mg / ^{m 2} or less, particularly preferably 0.01 mg / ^{m 2} or less. When OL exceeds 0.20 mg / m ² , for example, due to scratches attached with a roll or the like in the adhesion process, OL is generated during heating, resulting in a decrease in transparency of the adhesive and a decrease in adhesive strength of the adhesive layer. This causes troubles in the inspection process involving optical evaluation, and further causes problems such as causing process contamination.

  Means for satisfying the range of the inclination (orientation angle) of the orientation principal axis of the second release film of the present invention is a stretching ratio, and a stretching temperature as long as productivity does not decrease as a stretching condition during film formation. Is to devise.

  Next, in the present invention, a substrate-less double-sided pressure-sensitive adhesive sheet using a release film is used for touch panel applications, but the pressure-sensitive adhesive layer constituting the substrate-less double-sided pressure-sensitive adhesive sheet will be described below. . The pressure-sensitive adhesive layer in the present invention means a layer composed of an adhesive material, and conventionally known materials can be used as long as the gist of the present invention is not impaired. As one specific example, the case where an acrylic adhesive is used will be described below.

  In the present invention, the acrylic pressure-sensitive adhesive means a pressure-sensitive adhesive layer containing, as a base polymer, an acrylic polymer formed using an acrylic monomer as an essential monomer component. The acrylic polymer has (meth) acrylic acid alkyl ester and / or (meth) acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as an essential monomer component (more preferably as a main monomer component). ) It is preferably an acrylic polymer to be formed. Furthermore, the acrylic polymer is preferably an acrylic polymer formed using (meth) acrylic acid alkyl ester and acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as essential monomer components.

  The pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer formed using (meth) acrylic acid alkyl ester and acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as essential monomer components. preferable.

  In addition, the monomer component forming the acrylic polymer that is the base polymer in the pressure-sensitive adhesive layer of the present invention further contains a polar group-containing monomer, a polyfunctional monomer, and other copolymerizable monomers. It may be contained as a polymerization monomer component. In addition, said "(meth) acryl" represents "acryl" and / or "methacryl", and others are the same. Although not particularly limited, the content of the acrylic polymer as the base polymer in the pressure-sensitive adhesive layer of the present invention is preferably 60% by weight or more based on the total weight (100% by weight) of the pressure-sensitive adhesive layer. Preferably it is 80 weight% or more.

  As a monomer component for forming the acrylic polymer, a (meth) acrylic acid alkyl ester having a linear or branched alkyl group (hereinafter sometimes simply referred to as “(meth) acrylic acid alkyl ester”) is used. It can be used suitably. Specific examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth ) Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate , Octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylic acid Isodecyl, undecyl (meth) acrylate, dodecyl (meth) acrylate, (Meth) acrylic acid tridecyl, (meth) acrylic acid tetradecyl, (meth) acrylic acid pentadecyl, (meth) acrylic acid hexadecyl, (meth) acrylic acid heptadecyl, (meth) acrylic acid octadecyl, (meth) acrylic acid nonadecyl, (meta ) (Meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group such as eicosyl acrylate. Moreover, the (meth) acrylic acid alkyl ester may be used alone or in combination of two or more. Among them, (meth) acrylic acid alkyl ester having 2 to 14 carbon atoms in the alkyl group is preferable, and (meth) acrylic acid alkyl ester having 2 to 10 carbon atoms in the alkyl group is more preferable.

  Examples of the polar group-containing monomer include, for example, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and other carboxyl group-containing monomers or anhydrides thereof (such as maleic anhydride) Hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, Hydroxyl group-containing monomers such as vinyl alcohol and allyl alcohol; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N -Butoxymethyl (meth) acrylamide, N-hydroxy Amide group-containing monomers such as ethyl acrylamide; Amino group-containing monomers such as aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate; (meth) Glycidyl group-containing monomers such as glycidyl acrylate and methyl glycidyl (meth) acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; N-vinyl-2-pyrrolidone, (meth) acryloylmorpholine, Heterocycle-containing vinyl monomers such as N-vinyl pyridine, N-vinyl piperidone, N-vinyl pyrimidine, N-vinyl piperazine, N-vinyl pyrrole, N-vinyl imidazole, N-vinyl oxazole; sodium vinyl sulfonate, etc. Sulfonic acid group-containing monomer; 2-hydroxyethyla Phosphoric acid group-containing monomers such as Leroy Le phosphate; cyclohexyl maleimide, imide group-containing monomers such as isopropyl maleimide; 2-methacryloyloxy such acryloyloxyethyl isocyanate group-containing monomers such as isocyanate. The polar group-containing monomers can be used alone or in combination of two or more.

  Examples of the polyfunctional monomer include hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, Neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methanetri (meth) Examples include acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate. The said polyfunctional monomer can also be used individually or in combination of 2 or more types.

  The content of the polyfunctional monomer is preferably 0.5% by weight or less with respect to 100% by weight of the monomer component forming the acrylic polymer. When the content exceeds 0.5% by weight, for example, the cohesive force of the pressure-sensitive adhesive layer becomes too high, and the stress relaxation property is lowered.

  Examples of copolymerizable monomers (other copolymerizable monomers) other than the polar group-containing monomer and multifunctional monomer include cyclopentyl (meth) acrylate and cyclohexyl (meth) acrylate. (Meth) acrylic acid ester having an alicyclic hydrocarbon group such as isobornyl (meth) acrylate, and (meth) acrylic acid ester having an aromatic hydrocarbon group such as phenyl (meth) acrylate. (Meth) acrylic acid esters other than alkyl acrylates, alkoxyalkyl (meth) acrylates, polar group-containing monomers and polyfunctional monomers; vinyl esters such as vinyl acetate and vinyl propionate; styrene, Aromatic vinyl compounds such as vinyltoluene; ethylene, butadiene, isoprene, isobutylene, etc. Fins or dienes; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

  The acrylic polymer can be prepared by polymerizing the above monomer components by a conventionally known or conventional polymerization method. Examples of the polymerization method of the acrylic polymer include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method by active energy ray irradiation (active energy ray polymerization method). Among these, the solution polymerization method and the active energy ray polymerization method are preferable in terms of transparency, water resistance, production cost and the like.

  Examples of the active energy rays irradiated in the above active energy ray polymerization (photopolymerization) include ionizing radiation such as α rays, β rays, γ rays, neutron rays, electron rays, and ultraviolet rays, among others. Ultraviolet rays are suitable for the use of the present invention. Further, the irradiation energy, irradiation time, irradiation method, and the like of the active energy ray are not particularly limited as long as they do not impair the gist of the present invention.

  In the solution polymerization, various common solvents can be used. Examples of such solvents include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methylcyclohexane Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. A solvent can be used individually or in combination of 2 or more types.

  In preparing the acrylic polymer, a polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator (photoinitiator) can be used depending on the type of polymerization reaction. A polymerization initiator can also be used individually or in combination of 2 or more types.

  With respect to the photopolymerization initiator, it is not particularly limited, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, Photoactive oxime photopolymerization initiators, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, thioxanthone photopolymerization initiators, and the like can be used. The amount of the photopolymerization initiator used is not particularly limited as long as it does not impair the gist of the present invention. For example, the amount of the photopolymerization initiator is 0.1% relative to 100 parts by weight of the total amount of monomer components forming the acrylic polymer. A range of 01 to 0.2 parts by weight is preferred.

Specific examples of the benzoin ether photopolymerization initiator include, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one. And anisole methyl ether. Examples of the acetophenone photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4- (t-butyl). Examples include dichloroacetophenone. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropan-1-one. . Specific examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime. Examples of the benzoin photopolymerization initiator include benzoin. Examples of the benzyl photopolymerization initiator include benzyl.
Specific examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like. Specific examples of the ketal photopolymerization initiator include benzyldimethyl ketal. Specific examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like.

  Specific examples of the thermal polymerization initiator include azo polymerization initiators [for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis. (2-methylpropionic acid) dimethyl, 4,4′-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [ 2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (N, N′-di) Methyleneisobutylamidine) dihydrochloride], peroxide-based polymerization initiators (eg, dibenzoyl peroxide, tert-butylpermaleate, etc.), redox Scan type polymerization initiators and the like. The amount of the thermal polymerization initiator used is not particularly limited as long as it does not impair the gist of the present invention.

  In the acrylic pressure-sensitive adhesive layer used as one form of the pressure-sensitive adhesive layer in the present invention, a cross-linking agent, a cross-linking accelerator, a tackifier (for example, rosin derivative resin, polyterpene resin, petroleum resin, oil-soluble, if necessary) Phenol resins, etc.), anti-aging agents, fillers, colorants (pigments and dyes, etc.), UV absorbers, antioxidants, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, etc. An additive can be used in the range which does not impair the characteristic of this invention. Moreover, when forming an adhesive layer, various general solvents can also be used. The type of the solvent is not particularly limited, and those exemplified as the solvent used in the above solution polymerization can be used.

  The said crosslinking agent can control the gel fraction of an adhesive layer by bridge | crosslinking the base polymer of an adhesive layer. As crosslinking agents, isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents Agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, amine crosslinking agents, and the like, and isocyanate crosslinking agents and epoxy crosslinking agents can be preferably used. A crosslinking agent can also be used individually or in combination of 2 or more types.

Next, in the base material-less double-sided pressure-sensitive adhesive sheet of the present invention, when an acrylic pressure-sensitive adhesive composition is used at the time of forming a pressure-sensitive adhesive layer, which is a constituent unit, for example, an optical member (for example, a surface protective layer, a touch panel, And the display surface of the image display unit) is replaced with a transparent adhesive sheet having a refractive index close to that of an optical member compared to air, thereby improving light transmission and brightness of the image display device. In view of suppressing the decrease in contrast and contrast, the pressure-sensitive adhesive layer itself is preferably designed flexibly. For example, the storage elastic modulus (G ′) in dynamic viscoelasticity is preferably 1.0 × 10 ⁵ Pa or less, and more preferably 5.0 × 10 ⁴ Pa or less. When the storage elastic modulus (G ′) exceeds 1.0 × 10 ⁵ Pa, for example, when a gap existing between optical members is filled, the filled adhesive layer does not reach every corner, and peels off at the end, Or, problems such as floating occur.

  The thickness of the pressure-sensitive adhesive layer constituting the substrate-less double-sided pressure-sensitive adhesive sheet in the present invention is 4 μm to 200 μm, preferably 25 μm to 150 μm. When the thickness of the pressure-sensitive adhesive layer is 4 μm or less, for example, the gap generated between the optical members is too large, and it may be difficult to fill the entire area with the pressure-sensitive adhesive layer. A peeling defect called crying separation may occur. On the other hand, when the thickness of the pressure-sensitive adhesive layer exceeds 200 μm, the pressure-sensitive adhesive layer thickness becomes excessively thicker than the gap generated between the optical members, and the excess pressure-sensitive adhesive layer components protrude from between the optical members. May occur.

  Next, peeling between the pressure-sensitive adhesive layer of the present invention and the release film will be described. The peel strength of the first release film 31 corresponding to the light release side with respect to the pressure-sensitive adhesive layer 11 is preferably 5 to 15 gf / 50 mm. When the peeling force of the first release film is less than 5 gf / 50 mm, the release film may be easily peeled in a scene that does not need to be peeled. Further, when the peeling force of the first release film exceeds 15 gf / 50 mm, a peeling phenomenon called “floating” occurs between the second release film and the adhesive layer in the step of peeling the first release film.

  By keeping the absolute value of the peeling force of the first release film 31 low, even if the absolute value of the peeling force of the second release film 32 is lowered, the difference in the peeling force between the release films 31 and 32 is increased. It becomes possible. Moreover, the 1st release film 31 peels easily from the adhesive layer 11 in the scene which does not need to peel originally before use by making the peeling force of the 1st release film 31 or more into a fixed value or more. Alternatively, it is possible to prevent the first release film 31 from floating from the pressure-sensitive adhesive layer 11.

  On the other hand, the peeling force of the second release film 32 corresponding to the heavy peeling side is preferably 15 to 50 gf / 50 mm, more preferably 17 to 40 gf / 50 mm. When the peeling force of the second release film is less than 15 gf / 50 mm, there arises a problem such that a part of the second release film is peeled off when the first release film is peeled off. Moreover, when the peeling force of a 2nd mold release film exceeds 50 gf / 50mm, malfunctions, such as the component derived from the adhesion layer remaining in a 2nd mold release film, will arise.

  It is preferable that the base-material-less double-sided pressure-sensitive adhesive sheet of the present invention provides a difference in peel force between the first release film and the second release film in addition to the above-described peel force adjustment. The peeling force of the second release film 32 is usually 2.0 times or more, preferably 3.0 times or more of the peeling force of the first release film 31. When the peeling force of the second release film 32 is less than 2.0 times the peeling force of the first release film 31, the second release film 32 adheres when the first release film 31 on the light release side is peeled off. The phenomenon of floating from the agent layer 11 occurs, causing problems such as the adhesive layer component remaining on the second release film 32 or zipping.

  In the release film on the heavy release side used in the substrate-less double-sided pressure-sensitive adhesive sheet of the present invention, that is, in the second release film, an optical inspection of the pressure-sensitive adhesive coating process may be required. In order to reduce the occurrence of light interference colors, it is very important to optimize the inclination (orientation angle) of the orientation main axis of the release film.

  The orientation angle of the second release film is preferably 12 degrees or less, more preferably 9 degrees or less, and particularly preferably 6 degrees or less in the entire width. When the orientation angle is larger than 12 degrees, in the optical inspection, the light interference color becomes easy to see, and there arises a problem that the foreign matter inspection becomes difficult. However, in order to guarantee a total width of 6 ° or less, it is necessary to devise a stretching prescription described later, but productivity deterioration such as film breakage usually occurs. Further, in the release film processing in the subsequent process, mechanical properties change significantly as compared with the normal release film substrate, so that deterioration of the processing properties also becomes a problem.

In the present invention, characteristics were confirmed in the production of the transparent conductive film. As the constituent material of the transparent conductive film, metal oxides are preferably used from the viewpoints of transparency, durability, and weather resistance. Tin oxide (ITO), antimony-containing indium tin compound (ATO), tin oxide, zinc oxide (ZnO), indium zinc oxide (In ₂ O ₃ —ZnO) and the like are particularly preferably used. The method for forming the transparent conductive film is not particularly limited, and a conventionally known method can be employed. Specific examples include vacuum deposition, sputtering, and ion plating.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measurement method and evaluation method used in the present invention are as follows.

(1) Measurement of intrinsic viscosity of polyester:
1 g of polyester from which other polymer components and pigments incompatible with polyester were removed was precisely weighed, 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) was added and dissolved, and measurement was performed at 30 ° C.

(2) Measurement of average particle diameter (d50: μm):
The value of 50% of integration (weight basis) in the equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type manufactured by Shimadzu Corporation) was defined as the average particle size.

(3) Measuring method of amount of oligomer contained in polyester raw material:
About 200 mg of the polyester raw material is weighed and dissolved in 2 ml of a mixed solvent having a ratio of chloroform / HFIP (hexafluoro-2-isopropanol) of 3: 2. After dissolution, add 20 ml of chloroform, and then add 10 ml of methanol little by little. The precipitate is removed by filtration, and the precipitate is further washed with a mixed solvent having a chloroform / methanol ratio of 2: 1. The filtrate / washing solution is collected, concentrated by an evaporator, and then dried. After the dried product was dissolved in 25 ml of DMF (dimethylformamide), this solution was supplied to liquid chromatography (manufactured by Shimadzu Corporation: LC-7A) to determine the amount of oligomer in DMF, and this value was obtained as a chloroform / HFIP mixed solvent. Divide by the amount of the polyester raw material dissolved in the amount to make the amount of oligomers contained (% by weight). The amount of oligomer in DMF was determined from the peak area ratio between the standard sample peak area and the measured sample peak area (absolute calibration curve method).

  The standard sample was prepared by accurately weighing an oligomer (cyclic trimer) collected in advance and dissolving it in accurately measured DMF. The concentration of the standard sample is preferably in the range of 0.001 to 0.01 mg / ml.

The conditions for the liquid chromatograph were as follows.
Mobile phase A: Acetonitrile Mobile phase B: 2% acetic acid aqueous solution Column: “MCIGEL ODS 1HU” manufactured by Mitsubishi Chemical Corporation
Column temperature: 40 ° C
Flow rate: 1 ml / min Detection wavelength: 254 nm

(4) Thickness of the laminated polyester layer:
The film piece was fixed with an epoxy resin and then cut with a microtome, and the cross section of the film was observed with a transmission electron micrograph. Two of the cross-sections are observed in parallel with the film surface, and the interface is observed by light and dark. The distance between the two interfaces and the film surface was measured from 10 photographs, and the average value was defined as the laminated thickness.

(5) Measurement of solution haze of coating solution:
Using a Nippon Denshoku haze meter NDH-300A, the coating solution was put into a quartz cell and measured by a transmission method. An average value of three measurements was adopted.

(6) Release layer surface roughness measurement:
Using AFM Nano-R manufactured by Toyo Technica, a coating solution was applied to a polyester film and dried to obtain a measurement sample. In the contact mode, the surface roughness Sa (nm) was measured in a measurement range of 5 μm × 5 μm. Three average values were used.

(7) Coat thickness of the first and second coating layers and the release layer:
The cross section of the release film was cut out by a freezing ultrathin section method, and the laminated film portion was observed at an accelerating voltage of 100 kV by using a transmission electron microscope H-7100FA type manufactured by Hitachi, Ltd. by a stained ultrathin section method by RuO ₄ staining. , Took a photo shoot. The thickness of the laminated film was measured from the cross-sectional photograph.

(8) Determination of the amount of hydrogen (H ₂ ) gas generated after heat treatment on the release layer surface side:
A sample film of 40 cm ² is cut out in advance and weighed in advance for a release film that was kept for one day after production. Again cut out amount to be used for measuring the ^second corner 5 mm, (corresponding to about 0.213g in release film 38 [mu] m) of gas chromatography dedicated 20ml vial filling sample film. Next, 3 ml of a butanol solution in which 5% by weight of potassium hydroxide is dissolved (prepared by adding 1 g of potassium hydroxide to 19 g of butanol) is sampled with a pipetter, and the entire sample film is immersed in a 5% by weight of potassium hydroxide butanol solution. Add as follows. Thereafter, the vial is sealed using a crimper, and heat-treated at 50 ° C. for 1 hour using a heating block (model: HF21, manufactured by Yamato Kagaku). Thereafter, the amount of hydrogen (H ₂ ) gas generated from the sample film is quantitatively analyzed using the following gas chromatography measuring device, and judged according to the following criteria.

<< Gas chromatography measurement conditions >>
Equipment: EAGanalyzer (SENSORTEC Co, Ltd)
Measurement conditions: pressure Gauge Low: 0.05 MPa; High: 0.05 MPa
Column temperature: 50 ° C
Column flow rate: 30.0sccm
Syringe injection volume: 1cc
Measurement time: 5 min

(9) Evaluation of release layer peeling force:
Affixing one side of a double-sided adhesive tape (“No. 502” manufactured by Nitto Denko) to the surface of the release layer of the release film, then cutting it to a size of 50 mm × 300 mm and then leaving it at room temperature for 1 hour Measure. For the peeling force, a tensile tester (“Intesco model 2001 type” manufactured by Intesco Co., Ltd.) was used, and 180 ° peeling was performed under the condition of a tensile speed of 300 mm / min. The peeling force on the surface of the release layer of the release film is represented by gf / 50 mm.

(10) Release layer surface release characteristics:
The release characteristics were evaluated from the situation when the release film was peeled off from the laminated film having the adhesive layer. Judgment is based on the following criteria.
<Criteria>
A: The release film is peeled off cleanly, and the adhesive does not adhere to the release layer. B: The adhesive adheres to the release film.

(11) Release layer surface coating film adhesion:
The surface of the release layer of the release film was rubbed with a finger three times, and then a tape was applied to the rubbed portion to evaluate whether there was a catch when the tape was peeled off. Judgment is based on the following criteria.
<Criteria>
A: As before the rubbing with a finger, it does not get caught when the tape is peeled off.
B: The coating film rubbed with a finger falls off and feels caught when the tape is peeled off.

(12) Measurement of orientation (orientation angle) of orientation axis of release film:
The orientation of the polyester film was observed using a polarization microscope manufactured by Carl Zeiss, and the orientation angle was determined by measuring how many times the direction of the main orientation axis in the polyester film plane was tilted with respect to the width direction of the polyester film. This measurement was carried out at a total of three locations on the center and both ends of the film, and the largest orientation angle value among the three locations was taken as the maximum orientation angle.

(13) Measurement of transmittance of release film:
According to JIS-K7105, the total light transmittance of the release film was measured with an integrating sphere turbidimeter NDH-300A manufactured by Nippon Denshoku Industries Co., Ltd.

(14) Measurement of haze (turbidity) of release film:
According to JIS-K7105, the total light transmittance of the release film was measured with an integrating sphere turbidimeter NDH-300A manufactured by Nippon Denshoku Industries Co., Ltd.

(15) Measurement of OL extracted from the surface of the release layer:
In advance, the unheated release film is heated in air at 150 ° C. for 60 minutes. After that, the heat-treated film is brought into close contact with the inner surface of a box having a top and width of 10 cm and a height of 3 cm, and the box shape is obtained. The release layer surface should be inside. Next, 4 ml of DMF (dimethylformamide) is placed in the box prepared by the above method and left for 3 minutes, and then DMF is recovered. The recovered DMF was supplied to liquid chromatography (manufactured by Shimadzu Corporation: LC-7A) to determine the amount of OL in DMF, and this value was divided by the area of the film in contact with DMF to obtain the amount of film surface OL (mg / M ² ).

  The amount of oligomer in DMF was determined from the peak area ratio between the standard sample peak area and the measured sample peak area (absolute calibration curve method). The standard sample was prepared by accurately weighing OL (cyclic trimer) collected in advance and dissolving it in DMF accurately weighed. The concentration of the standard sample is preferably in the range of 0.001 to 0.01 mg / ml. The conditions for the liquid chromatograph were as follows.

Mobile phase A: Acetonitrile Mobile phase B: 2% acetic acid aqueous solution Column: “MCIGEL ODS 1HU” manufactured by Mitsubishi Chemical Corporation
Column temperature: 40 ° C
Flow rate: 1 ml / min Detection wavelength: 254 nm
The quality of the surface OL is judged based on the following criteria.
<Criteria>
A: Value is lower than 0.10 mg / m ² B: 0.10 to 0.20 mg / m ²
C: 0.20 to 0.50 mg / m ²
D: The value is higher than 0.50 mg / m ²

(16) Release film appearance:
Appearance defects due to the thickness of the coating film were evaluated. Evaluation was performed according to the following criteria. Judgment is based on the following criteria.
<Criteria>
A: Highly transparent and beautiful B: Slightly whitish C: Cloudy white

(17) Molding film formability:
When producing a polyester film, the film-forming yield is evaluated from the film breakage and film-forming characteristics under the stretching conditions. Further, in the subsequent film formation of the first coating layer and the second coating layer, the processing yield including appearance and characteristics is evaluated. Judgment is based on the following criteria.
<Criteria>
A: Sufficient continuity can be secured (level at which implementation and sale are possible)
B: Sufficient continuity cannot be ensured (it is difficult to implement and costs do not match)

(18) Adhesive processing characteristics:
A) Adhesive processing step roll soiling In the adhesive step, the roll soiling of the heating roll and / or the metal roll when the release film was quantitatively used was evaluated. Judgment is based on the following criteria.
<Criteria>
A: Roll dirt does not occur even if processed over 10,000m (practicable level)
B: Roll stains occur before processing 10,000 m (difficult level)

B) Adhesive processing step contamination The degree of contamination in the adhesive drying step when a release film was quantitatively used in the adhesive step was evaluated. Judgment is based on the following criteria.
<Criteria>
A: Contamination is not noticeable even after 1 week of production (practicable level)
B: Whitish contamination occurs before production for one week (difficult to implement)

C) Pressure-sensitive adhesive processing productivity In the pressure-sensitive adhesive process, it was comprehensively evaluated whether the above-mentioned A) and B) were not satisfied, and the foreign matter inspection property was poor, resulting in defects. Judgment is based on the following criteria.
<Criteria>
A: There is no pressure-sensitive adhesive process contamination, and foreign matter inspection is also good (practicable level).
B: Adhesive process is contaminated or foreign matter inspection is poor (difficult to implement)

D) OL generation in pressure-sensitive adhesive during processing Degree of oligomer crystal generation in pressure-sensitive adhesive when processed with a release film of 10000 m or more and pressure-sensitive adhesive (maximum temperature 150 ° C., 15 m / min, furnace length 100 m) To evaluate. Judgment is based on the following criteria.
<Criteria>
A: No OL occurs B: OL occurs

E) Durability evaluation of processed product The adhesive with a release film of the present invention was bonded to glass and subjected to heat and humidity treatment in order under the following conditions (1) to (3). The degree of oligomer crystal generation is evaluated.
(1) 160 ° C. × 60 minutes (2) 85 ° C. × 85% RH × 240 hours (3) 155 ° C. × 2 hours Judgment is based on the following criteria.
<Criteria>
A: No OL occurs B: OL occurs

F) Generation status of zipping The samples obtained in Examples and Comparative Examples were punched into cut plate sizes, and when peeling, the release status of the adhesive layer and the release film was observed, and the occurrence of zipping was evaluated in three stages. .

<Criteria>
A: Peeling extremely smoothly, no peeling stripes, no peeling noise B: Peeling stripes are observed, peeling noise is generated, and zipping occurs

G) Peelability of first and second release films The evaluation was made based on the situation of the release layer and the adhesive interface of the second release film when the first release film on the light release side was peeled off.

<Criteria>
A: No abnormality is observed in the release layer and the adhesive interface of the second release film B: Clear floating is observed in the release layer and the adhesive interface of the second release film

(19) Peel ratio of the first and second release films:
-Adhesive layer 11 was provided on the surface of the second release layer on the surface of the heavy release layer, and the other side was cut into a size of 50 mm x 300 mm after aging for 4 days with a plain film attached. Then, the peeling force of the second release film is measured.
A sample film on the light release side, the pressure-sensitive adhesive layer 11 is provided on the surface of the first release layer, and the release film on the heavy release side is bonded to the opposite side, and after aging for 4 days, 50 mm × 300 mm After cutting to size, the peel force of the first release film is measured.
For the peeling force, a tensile tester (“Intesco model 2001 type” manufactured by Intesco Co., Ltd.) was used, and 180 ° peeling was performed under the condition of a tensile speed of 300 mm / min. The release force (F) on the release layer surface side of the first and second release films is expressed as gf / 50 mm.
The peel force ratio means the second release film peel force / first release film peel force measured above. Judgment is based on the following criteria.
<Criteria>
A: 2.0 times or more B: Lower than 2.0 times, or crying, glue residue occurs

(20) First and second release film foreign matter inspection (visual):
When inspected by fluorescent light, transmission and reflection methods, it was evaluated whether transparency was maintained and foreign objects and scratches were easily found. In the observation, A4 size samples were cut out from a total of three locations in the center and both ends in the width direction of the obtained film.
Judgment is based on the following criteria.
<Criteria>
A: Good recognition of foreign matter B: Poor recognition of foreign matter

(21) Second release film foreign matter inspection property (polarization inspection):
Taking the polarizing plate inspection into consideration, the width direction of the release film obtained by applying a release agent on the film and having a dryer temperature of 120 ° C. and a line speed of 30 m / min is parallel to the alignment axis of the polarizing film. As described above, the release film was adhered to the polarizing film through the pressure-sensitive adhesive to obtain a polarizing plate. Here, when the polarizing plate was prepared, black metal powder (foreign matter) having a size of 50 μm or more was mixed between the pressure-sensitive adhesive and the polarizing film so as to be 50 / m ² . A polarizing plate for inspection is superimposed on the polarizing plate release film mixed with the foreign matter thus obtained so that the orientation axis is orthogonal to the width direction of the release film, and white light is irradiated from the polarizing plate side. Then, it was visually observed from a polarizing plate for inspection, and whether or not a foreign matter mixed between the adhesive and the polarizing film was found under crossed Nicols was evaluated according to the following criteria. In the observation, A4 size samples were cut out from a total of three locations in the center and both ends in the width direction of the obtained film. Judgment is based on the following criteria.
<Criteria>
A: Good recognition of foreign matter B: Poor recognition of foreign matter

(22) Processability of transparent conductive film member:
The release film on the heavy release side of the produced baseless pressure-sensitive adhesive sheet is peeled off, a transparent film base material (Mitsubishi Resin T600E23) is bonded, ITO (indium titanium oxide) is 150 ° C. at a line speed with a sputtering machine. 3 m / min. The processing characteristics when sputtering was performed under the following conditions were evaluated. Evaluation was made according to the following criteria.
<Criteria>
A: Uniform ITO film formation was confirmed without problems.
B: A uniform ITO film could not be formed.

(23) OL generation after processing of transparent conductive film member:
The release film on the heavy release side of the produced baseless pressure-sensitive adhesive sheet is peeled off, a transparent film base material (T600E23 made by Mitsubishi Plastics) is bonded, and after processing ITO (indium titanium oxide), it is wound from the obtained roll The OL performance was evaluated using the film sample. Evaluation was made according to the following criteria.
<Criteria>
A: There is no OL generation.
B: OL generation of ≧ 0.5 / m ² occurred.

(24) Comprehensive evaluation An evaluation is performed in consideration of film-forming properties, silicone, adhesive, sputter processability, functionality, and the like. Judgment is based on the following criteria.
<Criteria>
A: Even if it is produced, it can be sufficiently supplied as a product (the defective rate is lower than 100 ppm for processed products).
B: Productivity is poor, or defects in optical inspection frequently occur (the defect rate is 1000 ppm or more with respect to the processed product), or the appearance is poor by visual transmission.

The polyester used in the examples and comparative examples was prepared as follows.
<Method for producing polyester (a)>
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, adding tetrabutoxy titanate as a catalyst to the reactor, setting the reaction start temperature to 150 ° C., and gradually increasing the reaction temperature as methanol is distilled off. It was 230 degreeC after 3 hours. After 4 hours, the transesterification reaction was substantially completed, and then a polycondensation reaction was performed for 4 hours.
That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.61 due to a change in the stirring power of the reaction vessel, and the polymer was discharged under nitrogen pressure to obtain a polyester (a) having an intrinsic viscosity of 0.61.

<Method for producing polyester (b)>
In the production method of polyester (a), 0.2 part of silica particles having an average particle diameter of 2.0 μm dispersed in ethylene glycol was added, and the polycondensation reaction was stopped at a time corresponding to an intrinsic viscosity of 0.61. A polyester (b) having an intrinsic viscosity of 0.61 was obtained using a method similar to the method for producing polyester (a).

<Method for producing polyester (c)>
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, 0.09 parts by weight of magnesium acetate tetrahydrate as a catalyst is placed in the reactor, the reaction start temperature is set to 150 ° C., and the methanol is distilled off gradually. The reaction temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially terminated. After adding 0.04 part of ethyl acid phosphate to this reaction mixture, 0.04 part of antimony trioxide was added, and a polycondensation reaction was carried out for 4 hours. That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.63 due to a change in stirring power of the reaction tank, and the polymer was discharged under nitrogen pressure. The obtained polyester (c) had an intrinsic viscosity of 0.65 and an oligomer (cyclic trimer) content of 0.97% by weight.

<Method for producing polyester (d)>
“UVA3000PET” (polyester (d) manufactured by BASF Japan Ltd.) was used as a polyester masterbatch containing 30% by weight of an epoxy group-containing polymer. The intrinsic viscosity was 0.51.

<Method for producing polyester (e)>
In the method for producing polyester (a), after adding ethyl acid phosphate, the content of ethylene glycol slurry of divinylbenzene / styrene copolymer crosslinked particles having an average particle diameter of 1.0 μm is 0.6% by weight with respect to polyester. A polyester (e) was obtained using the same method as the method for producing the polyester (a) except that the polyester (a) was added. The obtained polyester (e) had an intrinsic viscosity of 0.63.

Example 1:
<Manufacture of release film>
The mixed raw materials in which the polyesters (a) and (b) are mixed at a ratio of 80% and 20%, respectively, are used as the outermost layer (surface layer) raw material, and the polyester (a) is used as the intermediate layer raw material in two extruders. 2 and 3 layers (I / II / I) on a cooling roll which is extruded from a die and melted at 290 ° C. and then set to a surface temperature of 40 ° C. using an electrostatic application adhesion method. Were coextruded and cooled and solidified to obtain an unstretched sheet.
Subsequently, the film was stretched 3.5 times in the machine direction at a film temperature of 100 ° C. using the difference in peripheral speed of the roll, and then the coating amount (after drying) of the following coating agent was applied to one side of the longitudinally stretched film. After coating to 03 g / m ² , it is guided to a tenter, stretched 4.2 times in the transverse direction at 120 ° C., heat-treated at 220 ° C. for 10 seconds, and then relaxed 4% in the width direction at 180 ° C. Was added to obtain a release film having a width of 4500 mm and a thickness of 25 μm (each surface layer of 2 μm and intermediate layer of 21 μm) having a first coating layer. Table 5 shows the properties of the obtained release film.

In addition, the compound used in order to comprise a 1st application layer is as follows.
(Example compounds)
-Quaternary ammonium base-containing polymer (A1):
2-hydroxy-3-methacryloxypropyltrimethylammonium salt polymer Counter ion: methyl sulfonate Number average molecular weight: 30000
-Polyethylene glycol-containing acrylate polymer (B1):
Polyethylene glycol-containing monoacrylate polymer Number average molecular weight: 20000
-Polyethylene glycol-containing acrylate polymer (B2):
Octoxy polyethylene glycol-polypropylene glycol monoacrylate polymer Number average molecular weight: 32000
・ Crosslinking agent (C1): Melamine crosslinking agent (DIC Corporation: Becamine “MAS”)
・ Crosslinking agent (C2): Oxazoline crosslinking agent (Nippon Shokubai: Epocross “WS500”)
Particle (D1): Alumina surface modified colloidal silica (average particle size: 50 nm)
Particle (D2): colloidal silica (average particle diameter: 70 nm)

On the first coating layer of the obtained release film substrate, the following coating agent was applied by a reverse gravure coating method so that the coating amount (after drying) was 0.05 g / m ² , and then 120 ° C., 30 It heat-processed for 2 seconds and the 1st release film base material which provided the 2nd application layer was obtained.

The coating agent composition used for constituting the second coating layer is as follows.
<< Coating composition >>
Organosiloxane (ethyl silicate 48: Colcoat)
: 0.9% by weight (based on 100% by weight of solvent)
The mixture was diluted with a mixed solvent of i-propanol / butanol = 6/4 to give 0.9% by weight.

On the first and second coating layers of the obtained release film substrate, reverse the release agent having the following release agent composition so that the coating amount (after drying) is 0.1 g / m ^2. It was applied by a gravure coating method, and a release layer was installed under conditions of a dryer temperature of 120 ° C. and a line speed of 30 m / min to obtain a roll-shaped first release film.

In addition, the mold release agent composition used in order to comprise a mold release layer is as follows.
<Releasing agent composition>
-Release layer composition-1
Curable silicone resin (KS-847H: manufactured by Shin-Etsu Chemical) 20 parts Catalyst (PL-50T: manufactured by Shin-Etsu Chemical) 2.0 parts MEK / toluene mixed solvent (mixing ratio is 1: 1)
Release layer composition-2
Curable silicone resin (LTC303E: manufactured by Toray Dow Corning) 20 parts Addition type platinum catalyst (SRX212: manufactured by Toray Dow Corning) 2.0 parts MEK / toluene / n-heptane mixed solvent (mixing ratio is 1: 1: 1) )
Release layer composition-3
Curable silicone resin (LTC856: manufactured by Toray Dow Corning) 20 parts Addition type platinum catalyst (SRX212: manufactured by Toray Dow Corning) 2.0 parts MEK / toluene / n-heptane mixed solvent (mixing ratio is 1: 1: 1) )
Release layer composition-4
Curable silicone resin (KS-847H: manufactured by Shin-Etsu Chemical Co., Ltd.) 17 parts Peeling control agent (KS-3800: manufactured by Shin-Etsu Chemical Co., Ltd.) 3 parts Addition type platinum catalyst (PL-50T: manufactured by Shin-Etsu Chemical Co., Ltd.) 2.0 parts MEK / toluene / N-heptane mixed solvent (mixing ratio is 1: 1: 1)
-Release layer composition-5
Curable silicone resin (X-62-5039: manufactured by Shin-Etsu Chemical Co., Ltd.) 14 parts Peeling control agent (KS-3800: manufactured by Shin-Etsu Chemical Co., Ltd.) 6 parts Cross-linking agent (X-92-185: manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 Part catalyst (PL-5000: manufactured by Shin-Etsu Chemical Co., Ltd.) 2.0 parts MEK / toluene / n-heptane mixed solvent (mixing ratio is 1: 1: 1)
-Release layer composition-6
Curable silicone resin (X-62-5039: manufactured by Shin-Etsu Chemical Co., Ltd.) 12 parts Peeling control agent (KS-3800: manufactured by Shin-Etsu Chemical Co., Ltd.) 8 parts Cross-linking agent (X-92-185: manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 Part catalyst (PL-5000: manufactured by Shin-Etsu Chemical Co., Ltd.) 2.0 parts MEK / toluene / n-heptane mixed solvent (mixing ratio is 1: 1: 1)

Examples 2-40, Comparative Examples 1-7:
By changing the various conditions in the table in the same manner as in Example 1, the release film substrates in Tables 1 to 4 below and the release films in Tables 5 and 6 were obtained.

Example 41:
<Manufacture of double-sided pressure-sensitive adhesive sheet>
As a 2nd mold release film, after apply | coating the coating liquid comprised from the following acrylic adhesive composition on the mold release layer of the mold release film L15 obtained by the said description with an applicator, a hot-air circulation Using a furnace, heat treatment was performed at 100 ° C. for 5 minutes to obtain an adhesive layer having a coating amount (after drying) of 25 g / m ² .
・ Acrylic adhesive layer forming composition (monomer composition)
2-ethylhexyl acrylate 70% by weight
2-methoxyethyl acrylate 29% by weight
4-hydroxybutyl acrylate 1% by weight
0.1 part of Nippon Polyurethane Coronate L was added to 100 parts by weight of the monomer composition to obtain an acrylic pressure-sensitive adhesive layer forming composition.
As the first release film, the release layer of the release film L1 obtained as described above and a 25 μm pressure-sensitive adhesive layer were bonded together to obtain a substrate-less double-sided pressure-sensitive adhesive sheet described in Example 41. Aging was performed at 60 ° C. for 4 days to complete a substrate-less double-sided PSA sheet. Table 7 shows the evaluation results of the obtained substrate-less double-sided pressure-sensitive adhesive sheet.

<Confirmation of workability of transparent conductive film member>
The first release film on the light side of the base material-less double-sided pressure-sensitive adhesive sheet of Example 41 thus obtained was peeled off and a transparent base material (Mitsubishi Resin T600E23) was bonded to the T600E23 surface side (the second release film was temporarily A sintered body material of 95% by weight of indium oxide and 5% by weight of tin oxide in an atmosphere of 0.4 Pa composed of 95% argon gas and 5% oxygen gas was used for the surface opposite to the attached surface). An ITO film (transparent conductive thin film) having a thickness of 25 nm was formed by reactive sputtering. Thereafter, 150 ° C., line speed 3 m / min. Then, crystallization was performed to obtain a transparent conductive film member.

Examples 42-65, Comparative Examples 8-12:
In Example 41, the first and second release film types and the pressure-sensitive adhesive thickness were changed, and a comparative study was performed as shown in Table 7.

  According to the present invention, it is a release film necessary for a capacitive touch panel member and a flat panel substrate, and particularly a highly transparent substrate-less double-sided pressure-sensitive adhesive sheet that dislikes foreign matter, and in particular, sputtering. Quality control is strict because it can be used under high-temperature conditions, and can prevent high-quality release film with excellent contamination inspection while preventing contamination of processes with severe cleanliness during processing. It can utilize suitably for an optical use.

DESCRIPTION OF SYMBOLS 1 Transparent conductive film member with a base material-less double-sided adhesive sheet 10 Base material-less double-sided adhesive sheet 11 Adhesive layer 13 Polyester intermediate layer of 1st release film base material: I layer 14 Polyester surface layer of 1st release film base material: II layer 14 'polyester surface layer of the first release film substrate: II layer 15 first application layer of the first release film 16 second application layer of the first release film 17 release layer of the first release film 23 Polyester intermediate layer of the second release film substrate: I layer 24 Polyester surface layer of the second release film substrate: II layer 24 ′ Polyester surface layer of the second release film substrate: II layer 25 of the second release film First application layer 26 Second application layer of second release film 27 Release layer of second release film 31 First release film 32 Second release film 41 Transparent conductive film member film substrate 42 Akirashirubedenmaku 51 transparent conductive film member

Claims (7)

At least one first application layer having a first application layer obtained by applying a coating solution containing a quaternary ammonium base-containing polymer, a polyethylene glycol-containing acrylate polymer, and a crosslinking agent to at least one surface of the base polyester film. On the layer, a second coating layer having a thickness of 10 to 100 nm is formed by coating a coating agent containing at least one organosiloxane compound, and a release layer is formed on at least one second coating layer. A release film characterized in that the amount of oligomer deposition on the film surface after heat-treating the release layer surface at 150 ° C. for 60 minutes is 0.5 mg / m ² or less.   The release film according to claim 1, wherein the first coating layer has a thickness of 20 to 100 nm.   The mold release according to claim 1 or 2, wherein the base polyester film is a laminated polyester film having a polyester layer containing 3000 to 30000 ppm of a polymer containing at least two epoxy groups in the molecular chain on both surfaces thereof. the film.   The release film according to claim 1 or 2, wherein the base polyester film is a laminated polyester film having polyester layers containing core-shell type particles having an average particle diameter of 0.5 to 3.0 µm on both surfaces thereof. .   A baseless double-sided pressure-sensitive adhesive sheet comprising a first release film having a relatively low peel force and a second release film having a relatively high peel force on both sides of an adhesive layer, the first release A base material-less double-sided pressure-sensitive adhesive sheet comprising the release film according to any one of claims 1 to 4 for either one of a film and a second release film.   The substrate-less double-sided pressure-sensitive adhesive sheet according to claim 6, wherein the thickness of the second release film is in a range of 150 µm or less, and the thickness is first release film ≤ second release film.   The base material-less double-sided pressure-sensitive adhesive sheet according to claim 5 or 6, wherein an inclination (orientation angle) of an orientation main axis of the second release film is 12 degrees or less.