JP5869432B2 - Double-sided release film - Google Patents

Description

  The present invention relates to a double-sided release film that can be suitably used, for example, for producing an anisotropic conductive film used for bonding with a conductive portion in a circuit board.

  Conventionally, a film in which conductive fine particles are dispersed in an insulating adhesive, a so-called anisotropic conductive film (hereinafter sometimes abbreviated as ACF), is a liquid crystal display and an IC chip or TCP (Tape Carrier Package). It is used for connection, connection between FPC (Flexible Printed Circuit) and TCP.

  In recent years, as electronic parts such as mobile phones have become smaller and higher in density, they are also applied to so-called flip chip mounting in which an IC chip is directly mounted on a display circuit or a printed circuit board.

  The anisotropic conductive film is characterized in that an anisotropic conductive film is provided between the electronic component and the circuit board, and the electrodes are electrically connected to each other by heating and pressing, and between adjacent electrodes. In such a usage method, the electronic component and the circuit board are bonded and fixed. In addition, the method for producing an anisotropic conductive film usually includes a release substrate (for example, a release layer provided on both sides of a polyester film) in which a coating liquid in which conductive fine particles are dispersed in an electrically insulating adhesive is dispersed. After coating and drying on the release surface of the double-sided release film), it is wound into a roll (at this time, the non-coated surface, that is, the back surface also serves as an ACF protective film), and then to a predetermined product width It consists of a slitting process.

  As a problem in using the double-sided release film, when pulling out the anisotropic conductive film from the double-sided release film, the ACF is transferred to the release film side or peeled off from the release film, or when the release film is peeled off, In some cases, the ACF may peel off from the circuit board together with the release film.

  In an anisotropic conductive film, for example, as described in Patent Document 1, it is common to form a film on a fluorine-based release film. However, since the adhesive strength difference between each release layer of the double-sided release film and the ACF is small, back transfer sometimes occurs easily when the ACF is pulled out. Therefore, for example, as described in Patent Document 2, a double-sided release film designed so that the adhesive strength to ACF on the ACF coated surface side is larger than that of the other surface tends to be generally used.

  In addition, the double-sided release film may be stored together with the anisotropic conductive film in a reel-like state for a long period of time, resulting in problems such as difficulty in peeling when the anisotropic conductive film is pulled out over time. was there. Therefore, the double-sided release film is in a situation where not only the peel force immediately after processing but also the change in peel force over time is required to be as small as possible.

  Further, in the anisotropic conductive film manufacturing process, when the anisotropic conductive film is peeled from the double-sided release film, problems such as adhesion of foreign matter due to charging or entrainment of foreign matter may occur.

  Furthermore, when the release layer of the double-sided release film and the anisotropic conductive film are stored for a long time in the form of a roll or a reel, it is inherently anisotropic due to transfer of the migration component from the release layer. In some cases, the adhesive strength of the conductive film cannot be sufficiently developed.

  As described above, for example, in the case of using a double-sided release film for producing an anisotropic conductive film, the double-sided release that has good release properties, release stability over time, antistatic properties, and good transferability There is a situation where a film is needed.

JP-A-5-154857 Japanese Utility Model Publication No. 4-87118 JP 2000-67647 A Japanese Patent Laid-Open No. 2000-100239 JP 2000-129157 A JP 2004-146261 A JP 2005-63904 A JP 2006-236759 A

  The present invention has been made in view of the above circumstances, and the problem to be solved is, particularly when used for the production of anisotropic conductive films, moderate peelability, peel stability over time, antistatic properties, and transferability. It is in providing the double-sided release film which is favorable.

  As a result of intensive studies in view of the above situation, the present inventor has found that the above problems can be easily solved by a double-sided release film having a specific configuration, and has completed the present invention.

That is, the gist of the present invention is a double-sided release film in which a release layer (A) is laminated on one side of a polyester film, and an application layer and a release layer (B) are sequentially laminated on the other side. The double-sided release film is immersed in the dissolved 1-butanol solution, and the amount of hydrogen gas generated after heat treatment at 50 ° C. for 1 hour is 80 ppm or less, and the surface resistivity (R) of one of the film surfaces is 1 × 10 ¹² (Ω) or less, and the press adhesion ratios of the release layer (A) and the release layer (B) are both 90% or more, and simultaneously satisfy the following formulas (1) and (2). It exists in the double-sided release film characterized by this.

15> γmax (B) −γmax (A) ≧ 5 (1)
40 ≧ γmax (B)> γmax (A) ≧ 27 (2)
(In the above formula, γmax (A) represents the maximum surface tension (dyne / cm) of the release layer (A) surface, and γmax (B) represents the maximum surface tension (dyne / cm) of the release layer (B) surface. )

  According to the present invention, particularly when used for producing an anisotropic conductive film, it is possible to provide a double-sided release film having good release properties, release stability over time, antistatic properties, and good transferability. Yes, its industrial value is high.

  In the present invention, the polyester film constituting the first and second release films may have a single-layer structure or a laminated structure. For example, the polyester film exceeds the gist of the present invention in addition to a two-layer or three-layer structure. As long as there is not, it may be a multilayer of four layers or more, and is not particularly limited.

  The polyester used for the polyester film in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyester includes polyethylene terephthalate (PET) and the like. On the other hand, 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 acid (eg, P-oxybenzoic acid). 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanol, neopentyl glycol, is mentioned. In any case, the polyester referred to in the present invention refers to a polyester which is polyethylene terephthalate or the like in which 60 mol% or more, preferably 80 mol% or more is an ethylene terephthalate unit.

  In the present invention, it is necessary to blend particles in the polyester layer for the main purpose of imparting slipperiness. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting concealability and slidability, and specific examples include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate. And particles of magnesium phosphate, kaolin, aluminum oxide, titanium oxide and the like. Moreover, you may use together the heat resistant organic particle | grains described in Japanese Patent Publication No.59-5216, Unexamined-Japanese-Patent No. 59-217755, etc. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used.

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

  Moreover, the average particle diameter of the particle | grains to be used is 0.01-3 micrometers normally, Preferably it is the range of 0.01-1 micrometer. When the average particle diameter is less than 0.01 μm, the particles are likely to aggregate and dispersibility may be insufficient. On the other hand, when the average particle diameter exceeds 3 μm, the surface roughness of the film becomes too rough and There may be a problem when a release layer is applied in the process.

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

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

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

  In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film in the present invention as necessary.

  The thickness of the polyester film constituting the double-sided release film of the present invention is not particularly limited as long as it can be formed as a film, but is usually 12 to 250 μm, preferably 25 to 125 μm, more preferably. It is the range of 25-100 micrometers.

  Next, although the manufacture example of the polyester film in this invention is demonstrated concretely, it is not limited to the following manufacture examples at all.

  First, 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 necessary 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 are 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 times, preferably 3.0 to 6 times. Subsequently, the extending | stretching temperature orthogonal to the 1st step | paragraph extending | stretching direction is 70-170 degreeC normally, and a draw ratio is 3.0-7 times normally, Preferably it is 3.5-6 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.

  The simultaneous biaxial stretching method can also be adopted for the production of the polyester film in the present invention. The simultaneous biaxial stretching method is a method in which the unstretched sheet is usually stretched and oriented in the machine direction and the width direction at 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is as follows: The area magnification is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times. 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, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be employed.

  Furthermore, a so-called coating stretching method (in-line coating) in which the film surface is treated during the above-described polyester film stretching step can be applied. When a coating layer is provided on a polyester film by a coating stretching method, coating can be performed simultaneously with stretching and the thickness of the coating layer can be reduced according to the stretching ratio, producing a film suitable as a polyester film. it can.

  The coating layer constituting the release film in the present invention preferably uses a cationic polymer in the coating layer in order to improve antistatic properties and oligomer precipitation preventing properties.

  The cationic polymer used in the present invention is preferably a polymer containing a quaternized nitrogen-containing unit as a repeating unit. In particular, the main chain represented by the following formula (I) or (II) has a pyrrolidinium ring. A cationic polymer containing a unit having a main repeating unit is preferred in that excellent antistatic performance can be obtained. These are also advantageous in that even if the amount of the cationic polymer is reduced, the decrease in the antistatic performance is small, so that the amount of the adhesive component can be increased instead and the adhesion of the coating layer can be improved. is there.

  In the structure of the above formula (I) or (II), R 1 and R 2 are preferably an alkyl group having 1 to 4 carbon atoms or hydrogen, and these may be the same group or different. Moreover, the alkyl group of R1 and R2 may be substituted with a hydroxyl group, an amide group, an amino group, or an ether group. Further, R1 and R2 may be chemically bonded and have a ring structure. X- in formula (I) or formula (II) is a halogen ion, nitrate ion, methanesulfonate ion, ethanesulfonate ion, monomethyl sulfate ion, monoethyl sulfate ion, trifluoroacetate ion, or trichloroacetate ion.

  Among the cationic polymers containing a unit having a pyrrolidinium ring in the main chain as a main repeating unit, particularly when the structure of formula (I) and X- is a chlorine ion, the antistatic performance is excellent, This is preferable in that the anti-static performance is less dependent on humidity and the decrease in the anti-static performance is reduced even under low humidity. In addition, in the case where halogen ions cannot be used for easily chargeable adhesion, antistatic performance close to that of chlorine ions can be obtained by using methanesulfonic acid or monomethylsulfuric acid ions instead of chlorine ions. The polymer having the unit of the formula (I) as a repeating unit is polymerized by using the diallylammonium salt represented by the following formula (III) as a monomer and ring-closing by radical polymerization in a medium mainly containing water. It is obtained by. The polymer having the unit of the formula (II) as a repeating unit can be obtained by cyclopolymerizing the monomer of the formula (III) in a system using sulfur dioxide as a medium.

  In addition, when the polymer having the unit represented by the formula (I) or (II) as a repeating unit is a homopolymer composed of a single unit, better antistatic performance can be obtained. As will be described later, in order to improve the transparency of the coating layer when the polyester film is further stretched after the coating solution containing the cationic polymer is applied to the polyester film, it is expressed by the formula (I) or (II). 0.1 to 50 mol% of the unit to be prepared may be replaced with other copolymerizable components.

As the monomer component used as the copolymer component, one or more compounds having a carbon-carbon unsaturated bond copolymerizable with the diallylammonium salt of the formula (III) can be selected.

  Specific examples include acrylic acid and salts thereof, methacrylic acid and salts thereof, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylamide, N -Methylol (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, maleic acid and its salt or maleic anhydride, fumaric acid and its salt or fumaric anhydride, monoallylamine and its 4 Grades, acrylonitrile, vinyl acetate, styrene, vinyl chloride, vinylidene chloride, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, dihydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylo Ruoxyethyldialkylamine and its quaternary product, (meth) acryloyloxypropyldialkylamine and its quaternary product, (meth) acryloylaminoethyldialkylamine and its quaternary product, (meth) acryloylaminopropyldialkylamine and its 4 Examples are grades.

  The cationic polymer in the coating layer is represented by, for example, the formula (IV) or (V) instead of the cationic polymer containing a pyrrolidinium ring as a repeating unit in the main chain represented by the formula (I) or (II). It may be a cationic polymer having a unit as a repeating unit.

  In the structure of the above formula (IV) or (V), R3 and R8 are each hydrogen or a methyl group, and R4 and R9 are preferably each an alkyl group having 2 to 6 carbon atoms, and R5, R6, R7, R10, R11, and R12 are a methyl group, a hydroxyethyl group, or hydrogen, and these may be the same group or different. Furthermore, X- in the formula (IV) or (V) is a halogen ion, nitrate ion, methanesulfonate ion, ethanesulfonate ion, monomethyl sulfate ion, monoethyl sulfate ion, trifluoroacetate ion, or trichloroacetate ion.

  The cationic polymer having a unit represented by the formula (IV) or (V) as a repeating unit, for example, radically polymerizes an acrylic acid monomer or a methacrylic acid monomer corresponding to each unit in a medium mainly containing water. However, the present invention is not limited to this.

  The average molecular weight (number average molecular weight) of the cationic polymer contained in the coating layer used in the present invention is usually in the range of 1000 to 500000, more preferably 5000 to 100000. When the average molecular weight is less than 1000, problems such as transfer or blocking of the cationic polymer on the surface where the films overlap each other during film winding are caused. On the other hand, when the average molecular weight exceeds 500,000, the viscosity of the coating solution becomes high, and it may be difficult to uniformly coat the film surface.

  For the purpose of further improving the durability of the coating layer, it is necessary to use a crosslinking agent in the coating layer in the present invention as long as the gist of the present invention is not impaired. 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 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 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 diisocyanate. And polymers and derivatives thereof.

  As an epoxy compound in 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, the amount of the crosslinking agent contained in the coating layer is usually 1 to 50% by weight, preferably 5 to 30% by weight. When it is out of the range, the durability adhesion of each coating layer may be insufficient.

  In the present invention, it is 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.

  Furthermore, it is preferable to contain particles for the purpose of improving the adhesion and slipperiness of the coating layer. Specific examples include silica, alumina, kaolin, calcium carbonate, titanium oxide, barium salt and the like.

  The compounding amount of the particles in the coating layer is usually 0.5 to 10% by weight, preferably 1 to 5% by weight. If the blending amount is less than 0.5% by weight, the blocking resistance may be insufficient. On the other hand, if it exceeds 10% by weight, the releasability may be affected.

  Further, as long as it does not impair the gist of the present invention, an antifoaming agent, a coating property improver, a thickener, an organic lubricant, organic polymer particles, an antioxidant, an ultraviolet ray may be included in the coating layer as necessary. Absorbent blowing agents, dyes and the like may be contained.

  When the coating layer in the present invention is provided on a polyester film by a coating stretching method (in-line coating), the solid content concentration is about 0.1% by weight to 50% by weight with the above series of compounds as an aqueous solution or a water dispersion. It is preferable to produce a polyester film in a manner in which a coating solution adjusted with reference to is applied onto the polyester film.

  In addition, a small amount of an organic solvent may be contained in the coating solution for the purpose of improving the dispersibility in water, improving the film forming property, and the like within a range not exceeding the gist of the present invention. Examples of the organic solvent include aliphatic or alicyclic alcohols such as n-butyl alcohol, n-propyl alcohol, isopropyl alcohol, ethyl alcohol, and methyl alcohol, glycols such as propylene glycol, ethylene glycol, and diethylene glycol, n-butyl cellosolve, Examples include glycol derivatives such as ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether, ethers such as dioxane and tetrahydrofuran, esters such as ethyl acetate and amyl acetate, ketones such as methyl ethyl ketone and acetone, and amides such as N-methylpyrrolidone. Can be mentioned. Only one type of organic solvent may be used, or two or more types may be used as appropriate.

The coating amount of the coating layer in the present invention (after drying) is generally 0.005~1g / ^{m 2,} preferably from 0.005 to 0.5 / ^{m 2,} more preferably of 0.005~0.1g / ^{m 2} It is a range. When the coating amount is less than 0.005 g / m ² , the uniformity of coating thickness may be insufficient, and the amount of oligomer deposited from the coating layer surface after heat treatment may increase. On the other hand, when the coating is applied in excess of 1 g / m ² , problems such as a decrease in slipperiness may occur.

Next, formation of the release layer in the present invention will be described.
The release layer constituting the double-sided release film in the present invention refers to a layer having releasability.

  The release layer in the present invention can be provided on the polyester film by the above-described coating stretching method (in-line coating). The coating stretching method (in-line coating) is not limited to the following, but for example, in sequential biaxial stretching, the first stage of stretching may be completed and the coating treatment may be performed before the second stage of stretching. it can. When a release layer is provided on a polyester film by a coating and stretching method, the film can be applied simultaneously with stretching, and the thickness of the release layer can be reduced according to the stretching ratio. Can be manufactured.

  Moreover, it is preferable that the release layer which comprises the double-sided release film in this invention contains a curable silicone resin in order to make mold release property favorable. It may be a type mainly composed of a curable silicone resin, 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 long as the gist of the present invention is not impaired. Also good.

  As the type of the curable silicone resin, any of the curing reaction types such as an addition type, a condensation type, an ultraviolet curable type, an electron beam curable type, and a solventless type can be used. Specific examples include KS-774, KS-775, KS-778, KS-779H, KS-847H, KS-856, X-62-2422, X-62-2461, X manufactured by Shin-Etsu Chemical Co., Ltd. -62-1387, 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-6720, TPR6500, TPR6501, UV9300, UV9425, XS56-A2775, XS56-A2982, UV9430, TPR6600, TPR6604, TPR6605, manufactured by Momentive Performance Materials Toray Dawkonin Examples include SRX357, SRX211, SD7220, SD7292, LTC750A, LTC760A, SP7259, BY24-468C, SP7248S, BY24-452, DKQ3-202, DKQ3-203, DKQ3-205, DKQ3-210, etc. Is done. Further, a release control agent may be used in combination to adjust the release property of the release layer.

In the present invention, the curing conditions for forming the release layer on the polyester film are not particularly limited, and when providing the release layer by off-line coating, usually at 120 to 200 ° C. for 3 to 40 seconds, The heat treatment is preferably performed at 100 to 180 ° C. for 3 to 40 seconds as a guide. Moreover, you may use together heat processing and active energy ray irradiation, such as ultraviolet irradiation, as needed. In addition, a conventionally well-known apparatus and an energy source can be used as an energy source for hardening by active energy ray irradiation. The coating amount (after drying) of the release layer is usually from 0.005 to 1 g / m ² , preferably from 0.005 to 0.5 g / m ² , more preferably from 0.01 to 5 in terms of coatability. The range is 0.2 g / m ² . When the coating amount (after drying) is less than 0.005 g / m ² , the coating property may be less stable and it may be difficult to obtain a uniform coating film. On the other hand, when the coating is thicker than 1 g / m ² , the coating layer adhesion and curability of the release layer itself may be lowered.

In the double-sided release film thus obtained, it is essential that the maximum surface tension of the release layer surface satisfies the following formulas (1) and (2) at the same time in order to improve the release property of each release layer. It is a requirement.

15> γmax (B) −γmax (A) ≧ 5 (1)
40 ≧ γmax (B)> γmax (A) ≧ 27 (2)
(In the above formula, γmax (A) represents the maximum surface tension (dyne / cm) of the release layer (A) surface, and γmax (B) represents the maximum surface tension (dyne / cm) of the release layer (B) surface. )
In the double-sided release film in the present invention, when either one of the above formulas (1) and (2) is out of the above range, the double-sided release film is different from the double-sided release film in a scene that does not need to be peeled off. In a scene where the directionally conductive film easily peels off or originally needs to be peeled off, the anisotropically conductive film becomes difficult to peel off from the double-sided release film. In the double-sided release film in the present invention, appropriate release properties can be imparted by satisfying the ranges of the above formulas (1) and (2) at the same time.

Further, the double-sided release film in the present invention has a surface resistivity (R) of 1 × on the surface of any one of the double-sided release films in order to suppress peeling electrification or adhesion of foreign matters during the processing step. It is necessary to be 10 ¹² (Ω) or less, and preferably 1 × 10 ¹¹ (Ω) or less. When the surface resistivity (R) is out of the above range, when the anisotropic conductive film is peeled off from the double-sided release film, problems such as adhesion of foreign matter due to peeling charging occur. The total light transmittance (TL) of the double-sided release film in the present invention is 70% or less, assuming that it corresponds to an inspection process involving optical evaluation or a manufacturing process that requires identification. It is preferable to satisfy, and more preferably 60% or less. When TL exceeds 70%, it may be difficult to cope with an inspection process involving optical evaluation.

  In the double-sided release film according to the present invention, for example, in the form of a reel-like product such as an anisotropic conductive film, the anisotropic conductive film and the release film are kept in contact with each other for a long time. In this case, the release layer was in a situation where the fluctuation of the peeling force over time was required to be as small as possible.

  As a countermeasure against such required characteristics, in the double-sided release film in the present invention, after the release film is treated with an alkaline solvent, it is necessary to keep the amount of hydrogen gas generated after heat treatment to 80 ppm or less, preferably 70 ppm or less. When the hydrogen gas generation amount exceeds 80 ppm, problems such as difficulty in peeling occur when the anisotropic conductive film bonded to the release layer is peeled from the release layer (B). Furthermore, in the present invention, it is possible to minimize fluctuations over time by limiting the amount of hydrogen gas generated within a predetermined range.

  In the double-sided release film in the present invention, as a specific method for suppressing the hydrogen gas generation amount to 80 ppm or less, for example, when a release control agent is used in combination for the purpose of adjusting release of the release layer, it is derived from a crosslinking agent. Select a type with a small amount of Si-H groups, select a type with a small amount of Si-H groups contained in the silicone resin used as the main agent, and increase the amount of catalyst added to accelerate the curing reaction The technique of doing is illustrated.

  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, the variation in peeling tends to increase as the amount of Si—H groups derived from the cross-linking agent decreases with time due to moisture absorption or the like. Therefore, after applying and drying a coating liquid in which conductive fine particles are dispersed in an electrically insulating adhesive as in the present invention and drying, the release layer of the double-sided release film and the anisotropic conductive film are adhered for a long time. When stored in a combined state, problems such as difficulty in peeling occur when the anisotropic conductive film is pulled out from the double-sided release film.

  In order to improve the problem, the present inventor previously made a 1-butanol solution in which 5% by weight of potassium hydroxide was dissolved in a double-sided release film and a Si—H group derived from a crosslinking agent in the release layer. Using the reaction, quantitative evaluation of the amount of hydrogen gas generated after the reaction is used as an evaluation index related to the peeling stability, and it has an advantage that the presence or absence of an inhibitory effect on peeling fluctuation can be determined.

  Furthermore, in the present invention, a heavy release control agent used for the purpose of heavy release is one having an M unit, D unit, or Q unit structure in order to ensure release stability over time. Is preferred.

  Usually, the siloxane structure is classified into four siloxane structural units as shown in the following general formula (A).

[Rm SiO _{(4-m) / 2} ] (A)
(In the above formula, R is an unsubstituted or substituted hydrocarbon group having a carbon atom bonded directly to a silicon atom and has no radical polymerizability, m represents an integer of 0 to 3)
In the formula (A), m = 0 (tetrafunctionality: Q unit), m = 1 (trifunctionality: T unit), m = 2 (bifunctionality: D unit), m = 3 (monofunctionality) : M unit).

  In the double-sided release film according to the present invention, in order to ensure release stability over time, a Q unit structure having a resin structure, mainly expressing a heavy release action, and a D unit structure expressing a release property are provided. Use of a balanced heavy release control agent is preferred for the purposes of the present invention. For example, when a heavy release control agent that does not include the D unit structure and is composed only of the M unit and the Q unit is used, the peeling fluctuation with time tends to increase. In the present invention, in the release layer (B) constituting the double-sided release film, the blending ratio of the curable silicone resin constituting the release layer and the release control agent is 100 parts of the curable silicone resin. It should be 10-80 parts. Regarding the range, a range of 20 to 80 parts is preferable. If it is out of the range, the desired heavy peeling force level cannot be reached after the release layer coating film is formed, or the hydrogen gas generation amount is out of the predetermined range, and the fluctuation of peeling over time becomes large.

  In the release layer (A) and the release layer (B) of the double-sided release film in the present invention, in order to suppress transfer of components derived from the release layer to the anisotropic conductive film that is the opposite substrate to be bonded. In addition, both the press adhesion ratios must be 90% or more. When the press adhesion rate of any one of the release layers is less than 90%, problems such as a decrease in the adhesive strength of the anisotropic conductive film itself occur.

  As an anisotropic conductive film constituent material applied on the release layer (B) surface of the double-sided release film in the present invention, it is essential to contain an insulating resin, a curing agent and conductive fine particles. However, other materials can be appropriately selected according to the purpose within a range not impairing the gist of the present invention. For example, a thermoplastic resin, a leveling agent, a pigment, a silane coupling agent, an inorganic filler, an organic filler and the like may be contained.

  Examples of the insulating resin and the curing agent include a thermosetting type, a photocuring type, and a combined type of thermosetting and photocuring.

Examples of the thermosetting type include a combination of an amine curing agent and an epoxy resin, a combination of a sulfonium salt curing agent and an epoxy resin, and a combination of an organic peroxide and a radical polymerizable resin. Specific examples of the amine curing agent include, for example, imidazole curing agents (for example, trade name: Novacure 3941HP manufactured by Asahi Kasei Co., Ltd.), alkylamines such as triethylamine, pyridine, and the like. Further, it may be a microcapsule type amine curing agent in which an insulating resin layer is provided on the outer shell.

There is no restriction | limiting in particular as a sulfonium salt hardening | curing agent, According to the objective, it can select suitably.

  Examples of the organic peroxide curing agent include lauroyl peroxide, butyl peroxide, and benzyl peroxide.

  Specific examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, and modified epoxy resins thereof. These may be used individually by 1 type and may use 2 or more types together.

  Specific examples of the radical polymerizable resin include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylol propane triacrylate, dimethylol tricyclodecane diacrylate, tetramethylene. Glycol tetraacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane , Dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloxyethyl) isocyanurate, urethane acrylate and the like. These may be used individually by 1 type and may use 2 or more types together. Furthermore, as said acrylic resin, what made the said acrylate the methacrylate is mentioned, These may be used individually by 1 type and may use 2 or more types together.

  Examples of the photo-curing type include a curing agent that generates an active cationic species or radical species in a wavelength region of 150 nm to 700 nm and a combination of the epoxy resin or the epoxy resin.

  Examples of the conductive particles include metal particles such as solder, nickel, and gold; resin particles, glass particles, and ceramic particles coated (plated) with a metal (nickel, gold, aluminum, copper, and the like). The particle diameter of the conductive particles is preferably 2 μm to 10 μm, more preferably 2 μm to 5 μm in terms of volume average particle diameter. When the volume average particle size is less than 2 μm, problems such as difficulty in classification may occur. On the other hand, if the thickness exceeds 10 μm, it may be difficult to cope with the narrowing of the junction terminals due to the fine pitch of the junction terminals. Moreover, as specific gravity of electroconductive particle, 1.5-3.0 are preferable. If the specific gravity is less than 1.5, it may be difficult to ensure the positional stability of the conductive particles on the surface to be processed. On the other hand, when the specific gravity of the conductive particles exceeds 3.0, it may be necessary to apply a higher electrostatic potential in order to arrange the conductive particles in a single layer.

Specific examples of the thermoplastic resin include urethane resin and phenoxy resin.
Specific examples of the leveling agent include acrylic polymerization resins such as acrylic oligomers, and silicones such as dimethyl silicone and methyl silicone.
Specific examples of pigments include titanium dioxide, zinc oxide, ultramarine, bengara, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, sulfate, and other inorganic pigments, azo pigments, copper phthalocyanine pigments, and other organic pigments, etc. Is exemplified.

  Specific examples of the silane coupling agent include vinyltris (2-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-acryloxypropyl. Trimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) Examples include -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  Specific examples of the inorganic filler include silica, alumina, titanium oxide, barium sulfate, talc, calcium carbonate, glass powder, and quartz powder.

  Specific examples of the organic filler include urethane powder, acrylic powder, and silicone powder.

  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 measuring method used in the present invention is 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 diameter (d ₅₀ : μm) Integration (weight basis) 50% in equivalent spherical distribution measured using centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type manufactured by Shimadzu Corporation) Was the average particle size.

(3) Measurement of peel force (F1 and F2) of double-sided release film After applying one side of double-sided adhesive tape (Nitto Denko “No. 502”) to the surface of each release layer of the sample film, 50 mm × 300 mm Cut to size and measure the peel force after standing at room temperature for 1 hour. For the peeling force, a tensile tester (“Intesco model 2001 type” manufactured by Intesco Co., Ltd.) was used, and 180 ° peeling was performed under a tensile speed of 300 mm / min.

(4) Measurement of maximum surface tension (γmax (A), γmax (B)) of release layer Several standards in which ethylene glycol is blended in an appropriate ratio with respect to ethanol and the surface tension is in the range of 20 to 40 dyne / cm Adjust the liquid. This surface tension is measured by Dunui's ring pull-up method. Next, this standard solution is dropped on the release layer of the sample film, and the contact angle (θ) between the standard solution and the release layer is measured. Next, a cos θ value is calculated from the obtained contact angle (θ), a plot (Zisman plot) of the cos θ value and the surface tension measured by the above method is created, and the slope of the straight line is b. The value of the surface tension at the intersection of the straight line of the Zisman plot and the straight line indicated by cos θ = 1 is γC (critical surface tension). Using b and γC thus obtained, γmax was determined from the following formula (I).

γmax = 1 / b + γC / 2 ...... Formula (I)
(In the above formula (I), b represents a constant obtained from the above-mentioned Zisman plot, and γC represents a critical surface tension obtained by the above-mentioned method.)

(5) Measurement of surface resistivity (R) of double-sided release film In the sample film, the surface resistivity (R) of the film surface provided with each release layer was measured and judged according to the following criteria. The measurement conditions were 23 ° C. and 50% RH atmosphere.
Yokogawa Hewlett-Packard's inner electrode 50mm diameter, outer electrode 70mm diameter concentric circular electrode 16008A (trade name) was placed on the sample in an atmosphere of 23 ° C, 50% RH, and a voltage of 100V was applied, The surface resistivity of the sample was measured with 4329A (trade name) which is a high resistance meter of the company.
<Criteria>
A: R (Ω) is 1 × 10 ¹⁰ or less (practical level, particularly good)
○: R (Ω) is 1 × 10 ¹¹ or less (practical level)
×: R (Ω) exceeds 1 × 10 ¹¹ (practical level)

(6) Evaluation of press-bonding rate of release surface << Press adhesive force >>
75 μm polyester film (Mitsubishi Resin Diafoil (T100 type)) / measurement sample film / 75 μm polyester film (Mitsubishi Resin Diafoil (T100 type)), temperature 60 ° C., pressure 1 MPa, time 120 minutes Press processing. After the press treatment, on the surface of the 75 μm polyester film that was in contact with the measurement sample film release layer surface, Nitto No. 31 tape is affixed and peeling force (A) 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.
《Basic adhesive strength》
To the same 75 μm polyester film used for the press treatment, Nitto No. A 31 tape is affixed, the peel force (B) is measured in the same manner as the peel force (A), and the press adhesion rate is determined based on the following formula. The measurement is performed at 20 ± 2 ° C. and 65 ± 5% RH.

(7) Determination of the amount of hydrogen (H ₂ ) gas generated from the double-sided release film after heat treatment A sample film of 40 cm ² is cut out in advance and weighed. Again cut out amount to be used for measuring the ^second corner 5 mm, filling the sample film to gas chromatography dedicated vial (20 mL). (Approximately 0.213 g with a 38 μm release film)
Next, 3 ml of 1-butanol solution (prepared by adding 1 g of potassium hydroxide to 19 g of 1-butanol) in which 5% by weight of potassium hydroxide is dissolved is separated with a pipetter, and the total amount of the sample film is 5% by weight of potassium hydroxide. Add soaked in 1-butanol solution. Thereafter, the vial (20 mL) is quickly sealed using a crimper, and heat-treated at 50 ° C. for 1 hour using a heating block (model: HF21, manufactured by Yamato Kagaku). Then, using the following gas chromatography measuring apparatus, the amount of hydrogen (H ₂ ) gas generated from the sample film was quantitatively analyzed and judged according to the following criteria.

<< Gas chromatography measurement conditions >>
Equipment: EAGanalyzer (SENSORTEC Co, Ltd)
Measurement condition:
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

<Criteria>
○: Less than 70 ppm (practical level, particularly good)
Δ: 70 ppm to 80 ppm (practical level)
X: Over 80 ppm (practical level)

(8) Centerline surface roughness of the mold release surface (Ra)
It calculated | required as follows using the Kosaka Laboratory Co., Ltd. surface roughness measuring machine (SE-3F). That is, a portion having a reference length L (2.5 mm) is extracted from the film cross-section curve in the direction of the center line, the center line of the extracted portion is the x axis, and the direction of the vertical magnification is the y axis. When represented by (x), the value given by the following equation is represented by [μm]. The center line average roughness was represented by the average value of the center line average roughness of the extracted portion obtained from 10 cross section curves obtained from the sample film surface. The tip radius of the stylus was 2 μm, the load was 30 mg, and the cutoff value was 0.08 mm.
Ra = (1 / L) ∫ 0 L | f (x) | dx

(9) Peeling property evaluation after anisotropic conductive film formation (practical property substitution evaluation)
A binder paste composed of the following material composition is applied onto the release layer (B) of the sample film so that the coating thickness (after drying) is 40 μm, heat-treated at 80 ° C. for 1 minute, and then coated with an anisotropic conductive film. A release film (38 μm × 250 mm width × 100 m length, 3 inch paper core surface one specification) was obtained. After normal temperature × 1 day and 40 ° C. × 85% RH × 7 days, the following determination criteria were used to determine the peelability when drawing the anisotropic conductive film from the double-sided release film.
<< Binder composition for forming anisotropic conductive film >>
Phenoxy resin (trade name YP50 manufactured by Toto Kasei Co., Ltd.): 50 parts by weight Epoxy resin (trade name Epicoat 828 manufactured by Japan Epoxy Resin Co., Ltd.): 60 parts by weight Imidazole-based curing agent (trade name HX3941HP manufactured by Asahi Kasei Corporation): 70 weights Part Silane coupling agent (trade name A187, manufactured by Nihon Unicar Co., Ltd.): 3.2 parts by weight Inorganic particles (SiO2 particles having an average particle diameter of 1 μm (silicon dioxide manufactured by Tatsumori Co., Ltd.)): 120 parts by weight The above binder composition Was dissolved in toluene to prepare an insulating adhesive resin (binder solution) having a solid content of 50%. Next, 7 parts by weight (12.3% by weight) of conductive vinyl particles having an average particle diameter of 5.0 μm and nickel-gold plating added to 100 parts by weight of the binder solution was used as a binder paste. .

<Criteria>
○: After 1 day and 7 days, both can be peeled off smoothly and peelability is good (practically no problem level)
Δ: After 7 days, peeling is felt slightly heavy (a level that may cause a problem in practical use)
X: Difficult to peel after 7 days. Peelability failure (practical problem level)

(10) Comprehensive evaluation (practical property substitution evaluation)
Using the double-sided release films produced in Examples and Comparative Examples, comprehensive evaluation was performed according to the following criteria for each evaluation item of peelability, peelability with time, antistatic property, and transferability.
<Criteria>
○: All of peelability, peelability with time, antistatic property, and transferability are ○ (a level that causes no problem in practical use)
Δ: At least one of peelability, peelability with time, antistatic property, and transferability is Δ (a level that may cause a problem in practical use).
X: At least one of peelability, peelability with time, antistatic property, and transferability is x (practically problematic level)

The polyester used in the examples and comparative examples was prepared as follows.
<Manufacture of polyester>
Production Example 1 (Polyester A)
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol and 0.09 part of magnesium acetate tetrahydrate are placed in a reactor, the temperature is raised by heating, methanol is distilled off, transesterification is performed, and 4 hours are required from the start of the reaction. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, after adding 0.04 part of ethylene glycol slurry ethyl acid phosphate and 0.03 part of antimony trioxide, the temperature reached 280 ° C. and the pressure reached 15 mmHg in 100 minutes. It was 0.3 mmHg. After 4 hours, the system was returned to normal pressure to obtain polyester A1 having an intrinsic viscosity of 0.61.

Production Example 2 (Polyester B)
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol and 0.09 part of magnesium acetate tetrahydrate are placed in a reactor, the temperature is raised by heating, methanol is distilled off, transesterification is performed, and 4 hours are required from the start of the reaction. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, 0.04 part of ethylene glycol slurry ethyl acid phosphate, 0.03 part of antimony trioxide and 0.2 part of silica particles having an average particle size of 3.4 μm were added, and then the temperature was 280 ° C. and the pressure was increased in 100 minutes. The pressure reached 15 mmHg, and the pressure was gradually reduced thereafter to finally reach 0.3 mmHg. After 4 hours, the system was returned to normal pressure to obtain polyester B having an intrinsic viscosity of 0.61.

Production Example 3 (Polyester C)
Polyester C was obtained in the same manner as in Production Example 1 except that 6 parts of titanium oxide particles having an average particle diameter of 0.3 μm were added instead of adding 0.2 parts of silica particles having an average particle diameter of 3.4 μm in Production Example 2. It was.

Production Example 4 (Polyester D)
Polyester D was obtained in the same manner as in Production Example 1 except that 18 parts of titanium oxide particles having an average particle diameter of 0.3 μm were added instead of adding 0.2 parts of silica particles having an average particle diameter of 3.4 μm in Production Example 2. It was.

Production Example 5 (Production of polyester film F1)
Two vented extruders using polyester A and C blended at 50% and 50% as the raw material for the surface layer, and polyester A and C as the raw material for the intermediate layer of 50% and 50%, respectively. Each was melted at 285 ° C. and then co-extruded on a casting drum cooled to 40 ° C. in a two-layer / three-layer configuration, and cooled and solidified to obtain a non-oriented sheet. Next, the film was stretched 3.3 times in the longitudinal direction at 85 ° C., and the following coating layer composition was applied by a bar coating method, followed by drying and preheating at 120 ° C. in a tenter, and 3.8 times transverse stretching. After that, heat treatment was performed at 220 ° C., and then 4% relaxation was applied in the width direction at 180 ° C., and a coating layer having a thickness (after drying) of 0.08 g / m 2 was provided (μm) A polyester film F1 having a thickness of 4/30/4 was obtained. The characteristics of the obtained polyester film F1 are shown in Table 1.

In addition, the compound which comprises the said coating layer is as follows.
<Coating layer>
Cationic polymer: (a1)
Quaternary ammonium salt-containing cationic polymer using diallyldimethylammonium chloride (pyrrolidinium ring-containing polymer of (Formula 1) described in paragraph 0029) Average molecular weight of about 30,000
-Binder polymer: (b)
Water-based acrylic resin (Nicarbazole with an acid value of 6 mgKOH / g, manufactured by Nippon Carbide Industries Co., Ltd.)
・ Crosslinking agent: (c1)
Methoxymethylol melamine (Dainippon Ink & Chemicals, Inc .: Beccamin J101)
Fine particles: (d1) Colloidal silica fine particles (average particle size 0.015 μm)
Additive: (e) Polyethylene oxide adduct to diglycerin skeleton (average molecular weight 450)
<Coating layer formulation example>
Cationic polymer: (a1): 37% by weight
-Binder polymer: (b): 30% by weight
Crosslinking agent: (c1): 25% by weight
Fine particles: (d1): 3% by weight
Additive: (e): 5% by weight
The coating composition was prepared to 10% by weight with ion exchange water.

Production Example 6 (Production of polyester film F2)
A polyester film F2 was obtained in the same manner as in Production Example 5 except that no coating layer was provided in Production Example 5. The characteristics of the obtained polyester film F2 are shown in Table 1.

Production Example 7 (Production of polyester film F3)
In the manufacture example 5, it manufactured similarly except using the polyester D instead of the polyester C, and obtained the polyester film F3. Table 1 shows the properties of the obtained polyester film F3.

Production Example 8 (Production of polyester film F4)
In the manufacture example 5, it manufactured similarly except using polyester B instead of polyester C, and obtained polyester film F4. Table 1 shows the properties of the obtained polyester film F4.

Example 1:
<Manufacture of double-sided release film>
On the coating layer of the polyester film F1 obtained in Production Example 5, the following release layer composition B is applied by a reverse gravure coating method so that the coating amount (after drying) is 0.1 g / m ² . After coating, heat treatment was performed at 120 ° C. for 30 seconds. Next, after applying the release layer (A layer composition) on the opposite film surface offline by a reverse gravure coating method so that the coating amount (after drying) is 0.1 g / m ² , Heat treatment was performed for 30 seconds to obtain a double-sided release film.
(Release layer (A layer composition))
Curable silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / toluene mixed solvent (mixing ratio is 1: 1): 1500 parts (release layer) (B layer composition))
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Heavy release control agent (BY24-4980: manufactured by Toray Dow Corning): 40 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / Toluene mixed solvent (mixing ratio is 1: 1) 1500 parts

Example 2:
In Example 1, it manufactured like Example 1 except having changed a mold release agent composition into the following mold release agent composition, and obtained the double-sided release film.
(Release layer (A layer composition))
Curable silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / toluene mixed solvent (mixing ratio is 1: 1): 1500 parts (release layer) (B layer composition))
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Heavy release control agent (BY24-4980: manufactured by Toray Dow Corning): 60 parts Hardening agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / Toluene mixed solvent (mixing ratio is 1: 1): 1500 parts

Example 3:
In Example 1, it manufactured like Example 1 except having changed a mold release agent composition into the following mold release agent composition, and obtained the double-sided release film.
(Release layer (A layer composition))
Curable silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / toluene mixed solvent (mixing ratio is 1: 1): 1500 parts (release layer) (B layer composition))
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Heavy release control agent (BY24-4980: manufactured by Toray Dow Corning): 80 parts Hardening agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / Toluene mixed solvent (mixing ratio is 1: 1): 1500 parts

Example 4:
In Example 1, it manufactured like Example 1 except having changed the polyester film F1 into the polyester film F3, and obtained the double-sided release film.
Example 5:
In Example 1, it manufactured like Example 1 except having changed a mold release agent composition into the following mold release agent composition, and obtained the double-sided release film.
(Release layer (A layer composition))
Curable silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 1 part MEK / toluene mixed solvent (mixing ratio is 1: 1): 1500 parts (release layer) (B layer composition))
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Heavy release control agent (BY24-4980: manufactured by Toray Dow Corning): 80 parts Hardening agent (PL-50T: manufactured by Shin-Etsu Chemical): 1 part MEK / Toluene mixed solvent (mixing ratio is 1: 1): 1500 parts

Example 6:
In Example 1, it manufactured like Example 1 except having changed the polyester film F1 into the polyester film F3, and obtained the double-sided release film.

Comparative Example 1:
In Example 1, it manufactured like Example 1 except having changed a mold release agent composition into the following mold release agent composition, and obtained the double-sided release film.
(Release layer (A layer composition))
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Heavy release control agent (BY24-4980: manufactured by Toray Dow Corning): 40 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / Toluene mixed solvent (mixing ratio is 1: 1): 1500 parts (release layer (B layer composition))
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Heavy release control agent (BY24-4980: manufactured by Toray Dow Corning): 40 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / Toluene mixed solvent (mixing ratio is 1: 1): 1500 parts

Comparative Example 2:
In Example 1, it manufactured like Example 1 except having changed a mold release agent composition into the following mold release agent composition, and obtained the double-sided release film.
(Release layer (A layer composition))
Curable silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / toluene mixed solvent (mixing ratio is 1: 1): 1500 parts (release layer) (B layer composition))
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Heavy release control agent (BY24-4980: manufactured by Toray Dow Corning): 100 parts Hardening agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / Toluene mixed solvent (mixing ratio is 1: 1): 1500 parts

Comparative Example 3:
In Example 1, it manufactured like Example 1 except having changed the polyester film F1 into the polyester film F2, and obtained the double-sided release film.

Comparative Example 4:
In Example 1, it manufactured like Example 1 except having changed a mold release agent composition into the following mold release agent composition, and obtained the double-sided release film.
(Release layer (A layer composition))
Curing type silicone resin (LTC303E: manufactured by Toray Dow Corning): 100 parts Curing agent (SRX212: manufactured by Toray Dow Corning): 2 parts MEK / toluene mixed solvent (mixing ratio is 1: 1): 1500 parts (release layer) (B layer composition))
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Heavy release control agent (BY24-4980: manufactured by Toray Dow Corning): 40 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / Toluene mixed solvent (mixing ratio is 1: 1); 1500 parts

Comparative Example 5:
In Example 1, it manufactured like Example 1 except having changed a mold release agent composition into the following mold release agent composition, and obtained the double-sided release film.
(Release layer (A layer composition))
Curable silicone resin (KS-847H: manufactured by Shin-Etsu Chemical): 100 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical): 2 parts MEK / toluene mixed solvent (mixing ratio is 1: 1): 1500 parts (release layer) (B layer composition))
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical Co., Ltd.): 100 parts Heavy release control agent (SD7292: Toray Dow Corning Co., Ltd.): 40 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical Co., Ltd.): 2 parts MEK / Toluene mixed solvent (mixing ratio is 1: 1): 1400 parts

Table 2 shows the characteristics of the double-sided release films obtained in the above Examples and Comparative Examples. In addition, the characteristic of the heavy peeling control agent used by the Example in this invention and a comparative example is shown below.
・ BY24-4980 (Toray Dow Corning)
M unit / D unit / Q unit = 0.16 / 0.28 / 0.56 (molar ratio) * 1
・ SD7292 (Toray Dow Corning)
M unit / Q unit = 0.32 / 0.68 (molar ratio)
* 1: The molar ratio was calculated using the peak value obtained by 29Si-NMR analysis.

  The double-sided release film of the present invention can be suitably used, for example, for producing an anisotropic conductive film.

Claims (1)

A double-sided release film in which a release layer (A) is laminated on one side of a polyester film, and an application layer and a release layer (B) are sequentially laminated on the other side, in a 1-butanol solution in which potassium hydroxide is dissolved The amount of hydrogen gas generated after the double-sided release film is immersed and heat-treated at 50 ° C. for 1 hour is 80 ppm or less, and the surface resistivity (R) of one of the film surfaces is 1 × 10 ¹² (Ω) or less. Both of the release layers (A) and the release layer (B) have a press adhesion ratio of 90% or more, and satisfy both the following formulas (1) and (2) at the same time: the film.
15> γmax (B) −γmax (A) ≧ 5 (1)
40 ≧ γmax (B)> γmax (A) ≧ 27 (2)
(In the above formula, γmax (A) represents the maximum surface tension (dyne / cm) of the release layer (A) surface, and γmax (B) represents the maximum surface tension (dyne / cm) of the release layer (B) surface. )