JP2015074732A - Base material-less double-sided adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base material-less double-sided adhesive sheet having no process contamination upon working and having excellent foreign matter examination properties.SOLUTION: Provided is a base material-less double-sided adhesive sheet obtained by laminating peel films with a lamination structure of at least three or more layers on both the sides of an adhesive layer, in which the peel force of the peel layer faces of each release film is different, both the surface layers of each release film are provided with polyester containing a polymer containing functional groups at least by two in 3,000 to 30,000, either side of each peel film is provided with a first coating layer obtained by coating a coating liquid containing a quaternary ammonium base-containing polymer, a polyethylene glycol-containing acrylate polymer and a crosslinking agent, the surface of the first coating layer is provided with a second coating layer with a thickness of 10 to 100 nm formed by coating a coating agent containing at least one kind of organosiloxane compound, and the opposite face of the second coating layer is provided with a peel layer.

Description

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

  Conventionally, various pressure-sensitive adhesive sheets for surface bonding between objects are known, and a baseless 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 substrate-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 adhered to the object surface of the other side to be bonded, and after the adhesion, the heavy release film is further peeled off, 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 conventional release films, especially release polyester films, rolls that exist during the process, especially metal rolls, heating rolls, scratches that enter during passage, temperature, and heat applied during adhesive processing are the causes. In some cases, a polyester film base material component (herein, an oligomer, which may be abbreviated as OL hereinafter) may be generated. In a normal release film, OL is surely generated by heating. 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 the release polyester 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 polyester 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.

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

  The present invention has been made in view of the above circumstances, and the problem to be solved is a substrate-less double-sided pressure-sensitive adhesive sheet used for a capacitive touch panel member, a flat panel substrate, etc. It is an object of the present invention to provide a high-quality substrate-less double-sided pressure-sensitive adhesive sheet that prevents contamination in severe processes and has excellent foreign matter inspection.

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

  That is, the gist of the present invention is a substrate-less double-sided pressure-sensitive adhesive sheet in which a release film having a laminate structure of at least three layers is laminated on both sides of the pressure-sensitive adhesive layer, and the release layer surface of each release film. The release force is different, and both surface layers of each release film contain polyester containing 3000 to 30000 ppm of a polymer containing at least two functional groups of epoxy groups, and quaternary ammonium is formed on one side of each release film. It has a first coating layer obtained by coating a coating solution containing a base-containing polymer, a polyethylene glycol-containing acrylate polymer, and a crosslinking agent, and contains at least one organosiloxane compound on the first coating layer. A second coating layer having a thickness of 10 to 100 nm, formed by coating a coating agent, on the opposite surface of the second coating layer It consists in substrate-less double-sided pressure-sensitive adhesive sheet characterized by having a release layer.

  According to the present invention, it is a substrate-less double-sided pressure-sensitive adhesive sheet necessary for mobile and TV applications, for example, capacitive touch panel members and flat panel substrates, and prevents contamination in processes that are severely clean during processing. And since the high quality base-material-free double-sided adhesive sheet which is excellent in foreign substance testability can be provided, the industrial value is high.

Schematic explanatory drawing showing the configuration of the substrate-less double-sided PSA sheet of the present invention

  The release film used in the present invention is required to be a multilayer film having at least three layers. The laminated polyester film for optics referred to in the present invention is a polyester film extruded by a so-called extrusion method that is melt-extruded from an extrusion die, and is oriented in the biaxial direction of the vertical direction and the horizontal direction as necessary. Film.

  In the present invention, 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. Typical polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN) and the like.

  The polyester used in the present invention 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 dimethanone neopentyl glycol, is mentioned.

  For the outermost layer of the release film used in the present invention, it is necessary to use a polyester containing 3000 to 30000 ppm of a polymer containing an epoxy group in its molecular chain. 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 polymer containing at least two functional groups in the molecular chain of the epoxy group used in the present invention is not limited as long as it is a polymer having compatibility 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 containing at least two functional groups in the molecular chain of the epoxy group used in the present invention is not limited as long as the molecular weight is compatible with the polyester resin, but the polymer used preferably The molecular weight range is such that the average molar molecular weight is in the range of 350 to 8000 g / mol, preferably 400 to 3000 g / mol, more preferably 500 to 3000 g / mol.

  The thickness of the outermost layer of the film of the present invention is preferably 4 μm or more, more preferably 5 μm or more, and further preferably 6 μm or more. When the thickness of the outermost layer is less than 4 μm, the oligomer reducing effect due to the epoxy group containing in the outermost layer may be diminished.

  In the polyester layer of the film used in the present invention, particles may be blended mainly for the purpose of imparting slipperiness and preventing generation 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, the heat-resistant organic particles 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.

  Although it does not specifically limit as an average particle diameter of the particle | grains mix | blended in a polyester film, Usually, 0.02-3 micrometers, Preferably it is 0.02-2.5 micrometers, More preferably, it is the range of 0.02-2 micrometers. It is. When particles having an average particle size of less than 0.02 μm are used, sufficient slipperiness may not be imparted, and as a result, the winding characteristics in the film manufacturing process may be inferior. On the other hand, when the average particle diameter exceeds 3 μm, the degree of roughening of the film surface becomes too large and the film may become hazy.

  Furthermore, the particle content in the polyester layer is usually in the range of 0.0005 to 0.5% by weight, preferably 0.001 to 0.3% by weight. When the particle content is less than 0.0005% by weight, the slipperiness of the film is insufficient, and appearance defects such as scratches may occur during film processing. On the other hand, when adding over 0.5 weight%, the transparency of a film may become inadequate.

  In the present invention, the method of blending the particles with the polyester is not particularly limited, and a known method can be adopted. For example, it can be added at any stage of producing the polyester, but it is preferably added as a slurry dispersed in ethylene glycol or the like at the stage of esterification or before the start of the polycondensation reaction after completion of the transesterification reaction, The polycondensation reaction may proceed. 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.

  Next, although the manufacture example of the base polyester film of a release film in this invention 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.

  Moreover, simultaneous biaxial stretching method can also be employ | adopted regarding base-material polyester film manufacture of the mold release film used by this invention. 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 used in the present invention is preferably within a range that does not decrease the yield during film formation and the yield during functional coating processing, and further ensures that the stiffness in the subsequent adhesive process is guaranteed. Preferably, it is usually in the range of 25 to 150 μm, preferably 38 to 125 μm. If it is thinner than 25 μm, the stiffness in the pressure-sensitive adhesive process may not be secured, and there may be a problem that the workability is deteriorated. If it is thicker than 150 μm, scratches may occur during processing of the functional coating film. Problems such as inability to wind may occur.

  Next, formation of the 1st application layer (it is a layer adjacent to a polyester base material) which comprises the release film used by 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.

  In the present invention, 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 the oligomer component from entering the process and preventing contamination. is there.

  Regarding the quaternary ammonium base-containing polymer used in the present invention, those having a constituent element containing a quaternary ammonium base in the main chain or side chain in the molecule are targeted. 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.

  In addition, 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. If it 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 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 may be difficult to obtain a desired oligomer 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 used in the present invention is usually 1000 or more, preferably 2000 or more, 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. About content of the polyethyleneglycol containing alkyl acrylate polymer which comprises the 1st coating layer in this invention, the range of 5 to 40 weight% is preferable in order to make stretching followability favorable. When it is out of the range, problems such as insufficient stretchability in forming the first coating layer may occur.

  Regarding the first coating layer constituting the release film used in the present invention, the quaternary ammonium base-containing polymer and the polyethylene glycol-containing acrylate polymer to be used may be a mixture or copolymerized in advance. It does not necessarily limit in the range which does not impair the summary of invention. 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 methylated group. 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 used in the present invention 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.

  The isocyanate compound used in the present invention 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 diene. Examples thereof include isocyanates, polymers and derivatives thereof.

  As an epoxy compound used by this invention, 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.

In the present invention, the thickness of the first coating layer is usually 0.002~1.0g / ^{m 2,} more preferably 0.005 to 0.5 / ^{m 2,} more preferably 0.01～0.2G / it is in the range of m ^2. When the film thickness is less than 0.002 g / m ² , sufficient adhesion may not be obtained. When the film thickness exceeds 1.0 g / m ² , the appearance, transparency, and film blocking properties may deteriorate. There is.

  In the polyester film of the present invention, 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.

  In the present invention, the drying and curing conditions for forming the first coating layer on the first and second release film substrates are not particularly limited. For example, when the coating layer is provided by offline coating, Usually, the heat treatment is performed at 80 to 200 ° C. for 3 to 40 seconds, preferably 100 to 180 ° C. for 3 to 40 seconds.

  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 polyester film constituting the laminated 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 first 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 example of the organosiloxane compound mix | blended in the coating agent used in order to form the 2nd coating layer in this invention is 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 wherein} R ¹ and R ² is each independently an organic group containing an epoxy group such as a γ-glycidoxypropyl group or a 3,4-epoxycyclohexylethyl group, or an alkoxy group such as a methoxy group or an 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.

  In this invention, the application quantity (after drying) of a 2nd application layer is 10-100 nm normally, Preferably it is the range of 20-100 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 tends to increase. On the other hand, if it exceeds 100 nm, the coating film is brittle even if it has OL sealing performance, and it is easy to cause scratches in the drying process and then the winding process after coating, and the film appearance tends to become cloudy. is there.

  In the present invention, the surface roughness (Sa) of the second coating layer is preferably 10 nm or less. When the surface roughness exceeds 10 nm, the OL sealing performance may deteriorate. 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.

  In the present invention, 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.

  In the present invention, the curing conditions for forming the second coating layer on the release film are usually heat-treated at 120 ° C. or higher, preferably 120 to 200 ° C. for 3 to 40 seconds, more preferably 120 to 160 ° C. Heat treatment is performed for 3 to 40 seconds as a guide. When the heat treatment is not performed at 120 ° C. or higher, the coating film formation may be incomplete and the amount of OL deposited may increase.

  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). In addition, 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. Causes inhibition of curing during layer formation. The technical key of this patent 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 opposite surface of the coating layer (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, SRX357, SRX211, SD7220, SD7292, manufactured by Toray Dow Corning Co., Ltd. , DKQ3-203, DKQ3-204, DKQ3-205, DKQ3-210, and the like. 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.

In the present invention, as a method for providing a release layer on the release film, a conventionally known coating method such as reverse roll coating, gravure coating, bar coating, doctor blade coating, etc. can be used. The application amount of the release layer in the present invention is usually in the range of 0.01 to 1 g / m ² .

  In the present invention, 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 may be subjected to corona treatment, plasma treatment, etc. A surface treatment may be applied.

  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 order to make the release layer of the release film of the present invention clean and strong, it is preferable to use a transition metal catalyst. The content of the transition metal catalyst in the coating layer is usually 0.5 to 5.0% by weight, preferably 1.5 to 4.0% by weight. When the content of the transition metal catalyst in the release layer is lower than 0.5% by weight, there may be a defect in peeling force or a curing reaction in the coating layer, resulting in a problem such as deterioration of the surface condition. On the other hand, when the content of the transition metal catalyst in the coating layer exceeds 5.0% by weight, the cost is increased, and the reactivity is increased and the gel foreign matter is generated. May cause problems.

In the present invention, for a release polyester film that was kept for one day after production, 3 ml of 1-butanol solution in which 5% by weight of potassium hydroxide was dissolved in a vial (20 mL) was added to ensure release stability over time. Add, further immerse the release film (40 cm ² ), heat the vial (20 mL) at 50 ° C. for 1 hour, and then suppress the amount of hydrogen (H ₂ ) gas generated from the release film to 60 ppm or less. Is more preferable, and 40 ppm or less is more preferable. 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, there may be problems such as difficulty in peeling.

In the present invention, as a specific method for suppressing the hydrogen (H ₂ ) gas generation amount to 60 ppm or less, for example, for the purpose of adjusting the peeling of the release layer, a silicone resin having a small amount of functional groups is used. When a control agent is used in combination, a method of selecting a type having a small amount of Si—H groups derived from a 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. Therefore, if the release layer and the pressure-sensitive adhesive layer of the release film are stored for a long time after applying the pressure-sensitive adhesive, problems such as heavy release may occur when the release film is peeled off. There is.

After heat-treating the surface of the second coating layer of the polyester film of the present invention (180 ° C., 10 minutes), the amount of OL extracted from the surface with dimethylformamide is preferably 0.20 mg / m ² or less, more preferably It is 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. In the inspection process with optical evaluation, troubles may be caused, and further, process contamination may be caused.

  In the release film of the present invention (heavy release side; hereinafter may be referred to as a second release film), an optical inspection of the adhesive coating process may be required, in which case generation of foreign matter or light interference color occurs. In order to reduce this, 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 of the present invention is desirably 12 degrees or less. Preferably it is 9 degrees or less, More preferably, it is 6 degrees or less. When the orientation angle is larger than 12 degrees, in the optical inspection, the light interference color is likely to be seen, and there may be a problem that the foreign matter inspection becomes difficult.

  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, the pressure-sensitive adhesive layer constituting the substrate-less double-sided pressure-sensitive adhesive sheet in the present invention 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.

  In the present invention, the pressure-sensitive adhesive layer 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. Is preferred.

  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 may be 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, there may be problems such as floating.

  The thickness of the pressure-sensitive adhesive layer constituting the substrate-less double-sided pressure-sensitive adhesive sheet in the present invention is 4 to 200 μm, preferably 25 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 becomes 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 release force of the release film corresponding to the light release side (hereinafter sometimes referred to as a first release film, 31 in the figure) 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.

  Even if the absolute value of the release force of the second release film (32 in the figure) is lowered by keeping the absolute value of the release force of the first release film low, the release force of both release films 31 and 32 The difference can be increased. 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, when the first release film is peeled off, problems such as a part of the second release film peeling off may occur. 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, may arise.

  The substrate-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. A phenomenon of floating from the agent layer 11 may occur, which may cause problems such as residual adhesive layer components on the second release film 32 or zipping.

  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 have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

(2) Measurement of average particle size (d50: μm) 50% integrated (weight basis) in equivalent spherical distribution measured using centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type manufactured by Shimadzu Corporation) The value 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 of chloroform / HFIP (hexafluoro-2-isopropanol) ratio 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: “MCI GEL ODS 1HU” manufactured by Mitsubishi Chemical Corporation
Column temperature: 40 ° C
Flow rate: 1 ml / min Detection wavelength: 254 nm

(4) Thickness of Laminated Polyester Layer After fixing a small piece of film with an epoxy resin, it was 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) Measurement of second coating layer surface side surface roughness 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 A cross section of the release polyester film was cut out by a freezing ultrathin section method, and a transmission electron manufactured by Hitachi, Ltd. was stained by an ultrathin section method by RuO ₄ staining. Using a microscope H-7100FA type, the laminated film portion was observed and photographed at an acceleration voltage of 100 kV. The thickness of the laminated film was measured from the cross-sectional photograph.

(8) Measurement of amount of metal in coating layer Using a fluorescent X-ray analyzer (model “XRF-1500” manufactured by Shimadzu Corporation), the amount of elements in the film was determined by single film measurement by the film FP method. . The detection limit in this method is usually about 1 ppm.

(9) Measurement of catalyst in release coating layer Using SAICAS, the sample film was obliquely cut to expose the cross section. Then, the amount of catalyst containing platinum contained in the polyester film coating layer was determined using TOF-SIMS (time-of-flight mass spectrometry mass spectrum).

(10) Determination of the amount of hydrogen (H ₂ ) gas generated after heat treatment on the side of the release layer The sample film 40 cm ^{2 in} advance is cut out and weighed with respect to the release polyester film placed on the first day after preparation. 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

(11) Measurement of orientation (orientation angle) of orientation main axis of second release film Using a polarizing microscope manufactured by Carl Zeiss, the orientation of the polyester film is observed, and the orientation of the main orientation axis in the polyester film plane is the polyester film. The orientation angle was measured by measuring how many times it was tilted with respect to the width direction. 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.

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

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

(14) Measurement of OL extracted from the surface of the second coating layer In advance, an unheated release film is heated in air at 180 ° C. for 10 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 second coating layer surface is on the 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: “MCI GEL 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>
○: Value is lower than 0.15 mg / m ² Δ: 0.15 to 0.20 mg / m ²
×: Value higher than 0.20 mg / m ²

(15) Appearance and visual evaluation of first and second release films provided with the second coating layer 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>
○: Transparent and beautiful △: Slightly whitish ×: Cloudy white

(16) Mold release film formation and processing productivity When producing a polyester film, the film formation yield is evaluated from the film breakage and film formation characteristics due to 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>
○: Sufficient continuity can be secured (level that can be implemented and sold)
X: Sufficient continuity cannot be ensured (it is difficult to implement and costs do not match)

(17) Adhesive Processing Characteristics A) Adhesive Processing Step Roll Dirt In the pressure-sensitive adhesive step, the roll contamination of the heating roll and / or metal roll when using a release film quantitatively was evaluated. Judgment is based on the following criteria.
<Criteria>
○: Roll stain does not occur even if processed over 10,000m (practicable level)
X: Roll dirt occurs before processing 10,000 m (level at which implementation is difficult)
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>
○ Contamination is not noticeable even after 1 week of production (practical level)
×: Whitish contamination occurs before production for 1 week (difficult to implement)
C) Adhesive processing productivity

In the pressure-sensitive adhesive process, it was comprehensively evaluated whether the above-mentioned A) and B) were not satisfied, or the foreign matter inspection property was poor and a defect was produced. Judgment is based on the following criteria.
<Criteria>
○: Adhesive process is not contaminated and foreign matter inspection is good (practicable level)
X: There is pressure-sensitive adhesive process contamination, or the foreign matter inspection property is poor (level that is difficult to implement)
D) Status of zipping occurrence Samples obtained in Examples and Comparative Examples were punched into cut plate sizes, and when peeling, the status of peeling between the adhesive layer and the release film was observed, and the occurrence of zipping was evaluated in three stages. .
<Criteria>
○: Peeling very smoothly, no peeling streaks, and no peeling noise.

X: Stripping streaks are observed, peeling sound is generated, and zipping occurs.
E) 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>
○: No abnormality is observed in the release layer and the adhesive interface of the second release film.

X: A clear float is seen in the release layer and adhesive interface of a 2nd release film.
F) Bleed-out occurrence situation of compound after pressure-sensitive adhesive processing and aging storage The storage situation of the sheet was observed at the stage of making the sheet, and the occurrence situation of the compound was evaluated in two stages.
<Criteria>
○: After 1 week or more after storage, the product is contaminated and the yield is lowered.
X: It becomes whitish after one week or more after storage.

(18) Evaluation of peeling force (F) between the pressure-sensitive adhesive layer and the release layer surface. Sample film on the heavy release side, the pressure-sensitive adhesive layer 11 is provided on the surface of the second release layer, and a plain film is provided on the opposite side. In the bonded state, after aging for 4 days, after cutting to a size of 50 mm × 300 mm, the peel force of the second release film is measured.
-Adhesive layer 11 was provided on the surface of the light release side sample film and the first release layer, and on the opposite side, a plain film was bonded, and after aging for 4 days, it was cut to a size of 50 mm x 300 mm Thereafter, 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.

(19) Peeling ratio of first and second release films 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>
○: 2.0 times or more ×: Lower than 2.0 times. Crying apart, 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>
○: Good foreign body recognition ×: Poor foreign body recognition

(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>
○: Foreign matter recognition good ×: Foreign matter recognition poor ○ and Δ are at a level where there is no problem in actual use.
Among the above criteria, those above ○ are levels that can be used without any problem in actual use.

(22) Comprehensive evaluation An evaluation taking film forming properties, workability, functionality, etc. into consideration is performed. Judgment is based on the following criteria.
<Criteria>
○: Even if it is produced, it can be sufficiently supplied as a product (the defect rate is 100% with respect to the processed product)
lower than ppm).
×: Productivity is poor and defects in optical inspection occur frequently (the defect rate is 100
0ppm or more)

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, 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 (a) had an intrinsic viscosity of 0.65 and an oligomer (cyclic trimer) content of 0.97% by weight.

<Method for producing polyester (b)>
“UVA3000PET” (polyester (b) 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 (c)>
In the production method of polyester (a), after adding 0.04 part of ethyl acid phosphate, 0.2 part of silica particles dispersed in ethylene glycol having an average particle diameter of 1.6 μm and 0.04 part of antimony trioxide are added. In addition, polyester (c) was obtained using the same method as the production method of polyester (a) except that the polycondensation reaction was stopped at the time corresponding to the intrinsic viscosity of 0.65. The obtained polyester (c) had an intrinsic viscosity of 0.65 and an oligomer (cyclic trimer) content of 0.82% by weight.

<Manufacture of first release film>
A mixed raw material obtained by mixing the polyesters (a), (b) and (c) at a ratio of 84.0% by weight, 1.0% by weight and 15% by weight, respectively, was used as a raw material for the surface layer (I layer), and polyester (a ) 100% of the raw material was used as a raw material for the intermediate layer (II layer), and each was supplied to two extruders, melted at 285 ° C., and then the I layer as the outermost layer (surface layer) and the II layer as the intermediate layer On a casting drum cooled to 40 ° C., two types and three layers (I / II / I) were coextruded so that the thickness composition ratio was I: II: I = 6: 26: 6, and cooled and solidified. An oriented sheet was obtained. 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 first release film substrate having a width of 4500 mm and a thickness of 25 μm having a first coating layer (6 μm for each surface layer and 13 μm for the intermediate layer).

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 polyester film, 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 heat-treated at 120 ° C. for 30 seconds. 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 opposite side of the first and second coating layers of the obtained first release film substrate, a release agent having a release agent composition shown below is applied in an amount (after drying) of 0.1 g / m ² . It applied so that it might become, and the release layer was installed on conditions with dryer temperature 120 degreeC and line speed 30m / min, and the roll-shaped 1st release film was obtained.

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) 1.0 part MEK / toluene mixed solvent (mixing ratio is 1: 1)
・ Releasing layer composition-2
Curable silicone resin (LTC303E: manufactured by Toray Dow Corning) 20 parts Addition type platinum catalyst (SRX212: manufactured by Toray Dow Corning) 1.0 part 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) 1.0 part 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.) 1.0 part MEK / toluene / N-heptane mixed solvent (mixing ratio is 1: 1: 1)

<Manufacture of second release film>
A mixed raw material obtained by mixing the polyesters (a), (b) and (c) at a ratio of 84.0% by weight, 1.0% by weight and 15% by weight, respectively, was used as a raw material for the surface layer (I layer), and polyester (a ) 100% of the raw material was used as a raw material for the intermediate layer (II layer), and each was supplied to two extruders, melted at 285 ° C., and then the I layer as the outermost layer (surface layer) and the II layer as the intermediate layer On a casting drum cooled to 40 ° C., two types and three layers (I / II / I) were coextruded so that the thickness composition ratio was I: II: I = 6: 26: 6, and cooled and solidified. An oriented sheet was obtained. Next, the film was stretched 2.8 times in the machine direction at a film temperature of 100 ° C. using the roll peripheral speed difference, and then the coating amount (after drying) of the following coating agent was applied to one side of the machine film. After coating to 03 g / m ² , it was guided to a tenter, stretched 5.1 times at 120 ° C. in the transverse direction, heat-treated at 220 ° C. for 10 seconds, and then relaxed 4% in the width direction at 180 ° C. Was added to obtain a second release film substrate having a width of 4500 mm and a thickness of 38 μm having a first coating layer (6 μm for each surface layer and 26 μm for the intermediate layer). In addition, the compound used in order to comprise a 1st application layer was made to be the same as that of 1st release film preparation.

  Moreover, the 2nd application layer of the 2nd mold release film base material was obtained similarly to 1st mold release film preparation.

On the opposite side of the first and second coating layers of the obtained second release film substrate, the coating amount (after drying) of the release agent comprising the release agent composition shown below is 0.1 g / m ² . In this way, it was applied by a reverse gravure coating method, and a release layer was placed under conditions of a dryer temperature of 120 ° C. and a line speed of 30 m / min to obtain a roll-like second 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-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.) 1.0 part 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)

Example 1:
<Manufacture of double-sided pressure-sensitive adhesive sheet>
On the release layer of the obtained 2nd release film, after coating the coating liquid comprised from the following acrylic adhesive composition with an applicator, using a hot-air circulation furnace, 100 degreeC, 5 It heat-processed for minutes and obtained the adhesive layer whose application amount (after drying) is 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. Next, using a 2 kg rubber roller, the release layer of the first release film and the 25 μm pressure-sensitive adhesive layer were bonded together to obtain a substrateless double-sided pressure-sensitive adhesive sheet of Example 1.

Examples 2 to 19:
In Example 1, the raw material compounding amount of the first and second release films, the change in the film-forming stretching conditions, the change in the thickness, the change in the second coating layer thickness, the release agent, and the thickness of the adhesive A substrate-less double-sided PSA sheet was obtained in the same manner as in Example 1 except for changing. The evaluation results of the produced substrate-less double-sided pressure-sensitive adhesive sheet were as shown in Tables 1 and 2.

Comparative Examples 1-9:
In Example 1, manufactured in the same manner as in Example 1, except that the raw material blending amounts of the first and second films, the film forming stretching conditions, the thickness, the second coating layer thickness, and the release agent are changed. Thus, a substrate-less double-sided pressure-sensitive adhesive sheet was obtained. The evaluation results of the produced substrate-less double-sided pressure-sensitive adhesive sheet were as shown in Table 3. Comparative Example 1 is an example in which the second coating layer is not provided.

Comparative Example 10:
In Example 1, it is the same method as Example 1 except having mixed polyester (a), (b), (c) as a raw material of I layer in the ratio of 75%, 10%, and 15%, respectively. A polyester film was tried. When the film was formed, an excessive load was applied to the extruder for the I layer, and a laminated polyester film could not be obtained (Table 3).

  The substrate-less double-sided pressure-sensitive adhesive sheet of the present invention can provide a high-quality substrate-less double-sided pressure-sensitive adhesive sheet that prevents contamination in a process with a strict cleanliness during processing and is excellent in foreign matter inspection. It can be suitably used for severe optical applications.

DESCRIPTION OF SYMBOLS 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 15 1st application | coating of 1st release film Layer 16 Second application layer of first release film 17 Release layer of first release film 23 Polyester intermediate layer of second release film substrate: I layer 24 Polyester surface layer of second release film substrate: II Layer 25 First application layer of second release film 26 Second application layer of second release film 27 Release layer of second release film 31 First release film 32 Second release film

Claims (3)

It is a substrate-less double-sided pressure-sensitive adhesive sheet in which a release film having a laminate structure of at least 3 layers is laminated on both sides of the pressure-sensitive adhesive layer, and the release force on the release layer surface of each release film is different. Both surface layers of the mold film contain polyester containing 3000 to 30000 ppm of a polymer containing at least two functional groups of epoxy groups, and on one side of each release film, a quaternary ammonium base-containing polymer and a polyethylene glycol-containing acrylate It has a first coating layer obtained by coating a coating solution containing a polymer and a crosslinking agent, and is formed by coating a coating agent containing at least one organosiloxane compound on the first coating layer. And having a second coating layer having a thickness of 10 to 100 nm, and having a release layer on the opposite surface of the second coating layer. Baseless double-sided pressure-sensitive adhesive sheet. The base-less double-sided pressure-sensitive adhesive sheet according to claim 1, wherein an inclination (orientation angle) of an orientation principal axis of one release film is 12 degrees or less. The base material-less double-sided pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the thickness of one release film is in the range of 25 to 150 µm and is equal to or less than the thickness of the other release film.

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