JP2005123025A - Anisotropic conductive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anisotropic conductive film excellent in conductivity in the direction along its thickness and insulation properties in the direction along its surface and usable without the problem of short circuit also in a narrow pitch circuit. <P>SOLUTION: In the anisotropic conductive film in which conductive particle are dispersed in an adhesive resin composition layer, the conductive particles satisfies the condition that (1) the load value is 0.100-0.600 gf at 30% compression when one particle is compressed and deformed at the loading speed of 0.23 gf/sec and the test load of 3 gf and (2) the average particle diameter is 2-7 μm. By mixing conductive particles having the small average particle diameter of 2-7 μm and the load value of 0.100-0.600 gf at 30% compression when one particle is compressed and deformed for the moderate softness, the stable performance is obtained without causing short circuit between adjacent terminals and between circuits also in a narrow pitch circuit. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an anisotropic conductive film having conductivity only in the thickness direction, and particularly relates to an anisotropic conductive film excellent in thickness direction conductivity and surface direction insulation suitable for a narrow pitch circuit.

  The anisotropic conductive film is formed by forming an adhesive resin composition in which conductive particles are dispersed, and conductivity is imparted in the thickness direction by applying pressure in the thickness direction. For example, the anisotropic conductive film is interposed between circuits that face each other, and pressurizes and heats between the circuits to connect the circuits through conductive particles, and adhesively fixes the circuits. Used for purposes.

  This anisotropic conductive film is different between various terminals including connecting a flexible printed circuit board (FPC) or TAB to an ITO (tin indium oxide) terminal formed on a glass substrate of a liquid crystal panel. It is used in the case of forming an isotropic conductive film, thereby bonding the terminals and electrically bonding them.

  Conventional anisotropic conductive films are generally composed of an epoxy or phenolic resin and an adhesive mainly composed of a curing agent, in which conductive particles are dispersed. Among them, adhesives are used for convenience in use. One-pack type thermosetting type is the mainstream. In addition, as an anisotropic conductive film, in order to obtain stable connection reliability even under high temperature and high humidity, the adhesion strength is enhanced by various methods. An anisotropic conductive film using a resin has low adhesive force, poor workability, and has a problem in moisture and heat resistance.

  In view of the above, the applicant of the present invention previously described an anisotropic conductive film comprising a heat or photocurable adhesive mainly composed of a polyacetalized resin obtained by acetalizing polyvinyl alcohol (Japanese Patent Laid-Open No. 10-338860). Japanese Laid-Open Patent Publication No. 2002-226815).

In addition, as an anisotropic conductive film that exhibits high adhesion to polyimide on the non-electrode surface of the non-adhesive type two-layer flexible printed circuit board, it is a heat mainly composed of a polyester unsaturated compound that is soluble in a solvent. Or the anisotropic conductive film (Unexamined-Japanese-Patent No. 2001-202831) which consists of a photocurable adhesive agent was proposed. That is, conventionally, as a flexible printed circuit board, a three-layer substrate composed of polyimide film / adhesive / copper foil has become widespread, but recently, heat resistance, flame retardancy, folding resistance, flexibility, etc. Therefore, a two-layer flexible printed circuit board composed of a polyimide film / copper foil without an adhesive layer has been widely used. However, the polyimide on the etching surface (non-electrode surface) of this two-layer flexible printed board has poor adhesiveness, and a conventional anisotropic conductive film could not obtain a sufficient adhesive force. Japanese Patent Application Laid-Open No. 2001-202831 solves this problem.
JP-A-10-338860 JP 2002-226815 A JP 2001-202831 A

  In recent years, the precision and miniaturization of circuit patterns have progressed in various fields, and the distance between circuits has become narrower, so that conventional anisotropic conductive films maintain insulation between adjacent terminals and between circuits. As a result, short-circuiting between adjacent terminals and circuits has become a problem.

  The present invention solves the above-mentioned conventional problems, is excellent in conductivity in the thickness direction, has excellent insulation in the surface direction, and can be applied to narrow pitch circuits without causing a short circuit problem. It aims at providing an anisotropic conductive film.

The anisotropic conductive film of the present invention is an anisotropic conductive film formed by forming an adhesive resin composition in which conductive particles are dispersed, wherein the conductive particles satisfy the following conditions (1) and (2): It is characterized by satisfying.
(1) The load value at 30% compression is 0.100 to 0.600 gf when compressively deforming one particle at a load speed of 0.23 gf / sec and a test load of 3 gf.
(2) Average particle size is 2-7μm
As long as the average particle diameter is as small as 2 to 7 μm and the conductive particle has a moderate softness such as 30% compression load value at a predetermined compression deformation of 0.100 to 0.600 gf, it is suitable for a narrow pitch circuit. However, stable performance can be exhibited without causing a short circuit between adjacent terminals or circuits.

  In addition, the load value at the time of 30% compression of the above (1) can be measured by, for example, a small compression tester “PCT-200 type” manufactured by Shimadzu Corporation.

  In this invention, it is preferable that the compounding quantity of electroconductive particle is 0.1-15 volume% with respect to the base resin in an adhesive agent resin composition.

  In addition, the adhesive resin composition as a raw material for forming an anisotropic conductive film has a polyacetalized resin obtained by acetalizing polyvinyl alcohol and / or an aliphatic unsaturated group introduced into the side chain of the polyacetalized resin. A thermosetting or photocurable resin composition containing a base resin made of a modified polyacetalized resin or a base resin mainly composed of a polyester unsaturated compound soluble in a solvent is preferable.

  The adhesive resin composition according to the present invention comprises 0.1 to 10 parts by weight of an organic peroxide or a photosensitizer, 100 parts by weight of a base resin, an acryloxy group-containing compound, a methacryloxy group-containing compound, and an epoxy group It is preferable to contain 0.5 to 80 parts by weight of at least one reactive compound selected from the group consisting of compounds, 0.01 to 5 parts by weight of a silane coupling agent, and 1 to 200 parts by weight of a hydrocarbon resin. .

  Such an anisotropic conductive film of the present invention is suitable as an anisotropic conductive film for narrow pitch circuits having a circuit pitch of 50 μm or less. Here, the circuit pitch is a value of a distance obtained by adding the electrode width (line width) and the width to the adjacent electrode (space width). For example, when the electrode width (line width) is 30 μm and the width to adjacent electrodes (space width) is 30 μm, the circuit pitch is 60 μm.

  The anisotropic conductive film of the present invention has excellent conductivity in the thickness direction and excellent insulation in the surface direction. Therefore, even for a narrow pitch circuit having a circuit pitch of 50 μm or less, between adjacent terminals, between circuits Thus, sufficient conduction can be obtained in the thickness direction without causing a short circuit.

  Hereinafter, embodiments of the present invention will be described in detail.

  First, the conductive particles used in the present invention will be described.

The conductive particles used in the present invention satisfy the following conditions (1) and (2).
(1) The load value at 30% compression is 0.100 to 0.600 gf when compressively deforming one particle at a load speed of 0.23 gf / sec and a test load of 3 gf.
(2) Average particle size is 2-7μm

  In the case of soft particles having a load value of 30% compression at the time of the predetermined compression deformation of the conductive particles of less than 0.100 gf, particle breakage occurs at the time of pressure bonding, and the resistance value is not stable. Conversely, particles having a load value of 30% compression greater than 0.600 gf are not preferable because the connection resistance value increases. A more preferable load value at 30% compression is 0.200 to 0.500 gf.

Further, when the average particle diameter of the conductive particles is smaller than 2 μm, it is difficult to sufficiently eliminate the base resin of the adhesive resin composition at the time of pressure bonding. Lack of sex. Further, when the average particle diameter is larger than 7 μm, the insulation in the plane direction is lowered, and a resistance value of 10 ⁶ Ω or more cannot be obtained in the evaluation of insulation described later. A more preferable average particle diameter is 3 to 5 μm.

  Any conductive particles may be used as long as the conductive particles satisfy the conditions (1) and (2) and are electrically good. For example, a metal or alloy powder such as copper, silver or nickel, a resin or ceramic powder coated with such a metal or alloy, and the like can be used. The shape is not particularly limited, and any shape such as a flake shape, a dendritic shape, a granular shape, or a pellet shape can be taken.

  The conductive particles satisfying the above condition (1) include plastic particles having polystyrene, polymethyl methacrylate (PMMA) or the like as a core material, and those plastic particles subjected to metal plating with a metal such as Ni. May include those plated on the outermost surface with Au.

The conductive particles preferably have an elastic modulus of 1.0 × 10 ^{7 to} 1.0 × 10 ¹⁰ Pa. That is, when an anisotropic conductive film is used to connect an adherend such as a liquid crystal film using a plastic film as a base material, cracks may occur in the adherend if conductive particles having a high elastic modulus are used. It is recommended to use conductive particles in the above elastic modulus range because there is a possibility that stable conduction performance cannot be obtained due to the occurrence of springback due to breakage of the particles or recovery of elastic deformation of the particles after pressure bonding. This prevents destruction of the adherend, suppresses the occurrence of springback due to recovery of elastic deformation of the particles after pressure bonding, and makes it possible to increase the contact area of the conductive particles for more stable reliability. High conduction performance can be obtained. If the elastic modulus is less than 1.0 × 10 ⁷ Pa, the particles themselves may be damaged and the conduction characteristics may be deteriorated. If the elastic modulus is more than 1.0 × 10 ¹⁰ Pa, the occurrence of springback may occur. There is. As such conductive particles, those obtained by coating the surfaces of the plastic particles having the above-described elastic modulus with the aforementioned metal or alloy are preferably used.

  In this invention, it is preferable that the compounding quantity of such electroconductive particle is 0.1-15 volume% with respect to the below-mentioned base resin in an adhesive agent resin composition, and if it is such a compounding quantity The conductive particles are condensed between adjacent circuits, and it becomes difficult to short-circuit, and good conductivity can be obtained.

  Next, other components of the adhesive resin composition according to the present invention will be described.

  The base resin of the adhesive resin composition is a polyacetalized resin obtained by acetalizing polyvinyl alcohol and / or a modified polyacetalized resin obtained by introducing an aliphatic unsaturated group into the side chain of this polyacetalized resin, or a solvent Polyester unsaturated compounds that are soluble in water are preferred.

  As the polyacetalized resin, those having an acetal group ratio of 30 mol% or more are preferable. If the ratio of the acetal group is less than 30 mol%, the moisture resistance may be deteriorated. Examples of the polyacetalized resin include polyvinyl formal, polyvinyl butyral and the like, and polyvinyl butyral is particularly preferable. As such a polyacetalization resin, a commercial item can be used, for example, "Denka PVB3000-1" "Denka PVB2000-L" etc. by Denki Kagaku Kogyo Co., Ltd. can be used.

  As the modified polyacetalized resin, modified polyvinyl butyral is preferable.

  The polyvinyl butyral resin is composed of a vinyl butyral unit A, a vinyl alcohol unit B, and a vinyl acetate unit C as shown in the following formula (1). The aliphatic unsaturated group may be introduced into any side chain of these units A, B and C, but those introduced into the side chain of the polyvinyl alcohol unit B are preferred. As the aliphatic unsaturated group, for example, a vinyl group, an allyl group, a methacryl group, an acrylic group, and the like are preferable.

  The introduction of the aliphatic unsaturated group into the side chain of the polyvinyl alcohol unit B is preferably carried out by acid-modifying the side-chain hydroxyl group. Examples of acids used for the acid modification include acrylic acid, methacrylic acid, stearyl. Examples thereof include acid, maleic acid, phthalic acid, and the like, and an aliphatic unsaturated bond can be introduced as shown in the following formula (2).

（式中、Ｒは水素原子又はアルキル基、Ｒ’はアルケニル基等の脂肪族不飽和基又はこれを含有する基を示す。）

(In the formula, R represents a hydrogen atom or an alkyl group, and R ′ represents an aliphatic unsaturated group such as an alkenyl group or a group containing the same.)

  In the above formula (1), the vinyl alcohol unit B is preferably 3 to 70 mol%, more preferably 5 to 50 mol%, still more preferably 5 to 30 mol%. When the amount is more than 70 mol%, heat resistance and moisture resistance may be inferior.

In the present invention, the base resin is a solvent that is a main component of the adhesive (wherein the solvent is an organic solvent such as acetone, MEK, ethyl acetate, cellosolve, dioxane, THF, benzene, cyclohexanone, Solvesso 100, etc. It may be composed of a polyester unsaturated compound soluble in This polyester unsaturated compound is a radical reaction such as an unsaturated polyester obtained by reacting a polybasic acid and a polyhydric alcohol, and a compound in which a (meth) acryloxy group is introduced into a saturated copolymer polyester soluble in a solvent. It is a curable polyester unsaturated compound. That is, with this polyester unsaturated compound
(i) Unsaturated polyester compound
(ii) Two types of compounds in which a (meth) acryloxy group and / or a methacryloxy group are introduced into a saturated polyester.

  Here, the saturated copolyester soluble in the solvent is mainly composed of terephthalic acid and ethylene glycol and / or 1,4-butanediol, and 5 to 50 mol% of phthalic acid and isophthalic acid in the total acid components. 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, in an amount of 5 to 50 mol% of acid components such as adipic acid, sebacic acid, dodecanoic acid and / or all alcohol components, One or more alcohol components such as 2-diethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,6-hexanediol and 1,9-nonanediol Copolymerized with

As a method for introducing a (meth) acryloxy group into such a saturated copolymerized polyester,
(a) a method of reacting an isocyanate alkyl (meth) acrylate with a hydroxyl group of the saturated copolymerized polyester,
(b) a method by transesterification of an alkyl (meth) acrylate and a hydroxyl group of the saturated copolymer polyester,
(c) A method of reacting an isocyanate alkyl (meth) acrylate by a reaction between a diisocyanate compound and a hydroxyalkyl (meth) acrylate with a hydroxyl group of the saturated copolymerized polyester can be employed.

  In the adhesive resin composition which concerns on this invention, you may mix | blend at least 1 sort (s) of phosphoric acid (meth) acrylate, a melamine type resin, and an alkyd resin for the adhesive improvement of an anisotropic conductive film.

  As phosphoric acid (meth) acrylate, phosphoric acid acrylate and / or phosphoric acid methacrylate are used. That is, (meth) acrylate is a general term for acrylate and methacrylate. Examples of phosphoric acid acrylate and phosphoric acid methacrylate include acid phosphooxyethyl (meth) acrylate, acid phosphooxypropyl (meth) acrylate, 2-methacryloyloxyethyl acid phosphate, diphenyl-2-methacryloyloxyethyl phosphate, and the like. A seed | species or 2 or more types is mentioned. Such a phosphoric acid compound is preferably blended in an amount of 0.1 to 10 parts by weight, particularly 0.5 to 2 parts by weight, based on 100 parts by weight of the base resin. If the amount of the phosphoric acid compound is less than 0.1 parts by weight, sufficient adhesive improvement effect cannot be obtained, and if it exceeds 10 parts by weight, the conduction reliability is deteriorated.

  Examples of the melamine resin include one or more of melamine resin, isobutylated melamine resin, butylated melamine resin such as n-butylated melamine resin, and methylated melamine resin. Such a melamine-based resin is preferably blended in an amount of 1 to 200 parts by weight, particularly 1 to 100 parts by weight, based on 100 parts by weight of the base resin.

  As the alkyd resin, either a pure alkyd resin or a modified alkyd resin may be used, but an oil-free or short oil type or medium oil type resin is preferable. Such an alkyd resin is preferably blended in an amount of 0.01 to 10 parts by weight, particularly 0.5 to 5 parts by weight, based on 100 parts by weight of the base resin.

  In this adhesive resin composition, a urea-based resin may be blended in order to prevent bubbles from being mixed into the adhesive layer and to ensure higher conductivity and adhesive strength. As the urea resin, urea resin, butylated urea resin, or the like can be used. For the same purpose, phenol resin, butylated benzoguanamine resin, epoxy resin and the like can be used.

  It is preferable that the resin for preventing air bubbles from mixing, such as urea-based resin, is 0.01 to 10 parts by weight, particularly 0.5 to 5 parts by weight with respect to 100 parts by weight of the base resin.

  In the present invention, an adhesive resin composition is used to improve or adjust the physical properties (mechanical strength, adhesiveness, optical properties, heat resistance, moisture resistance, weather resistance, crosslinking speed, etc.) of the anisotropic conductive film. It is preferable to add a reactive compound (monomer) having an acryloxy group, a methacryloxy group or an epoxy group. As this reactive compound, acrylic acid or methacrylic acid derivatives, such as esters and amides thereof, are most common, and as ester residues, in addition to alkyl groups such as methyl, ethyl, dodecyl, stearyl, lauryl, cyclohexyl Group, tetrahydrofurfuryl group, aminoethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, 3-chloro-2-hydroxypropyl group and the like. Further, esters with polyfunctional alcohols such as ethylene glycol, triethylene glycol, polypropylene glycol, polyethylene glycol, trimethylolpropane, and pentaerythritol are also used. A typical amide is diacetone acrylamide. Examples of the polyfunctional crosslinking aid include acrylic acid or methacrylic acid ester such as trimethylolpropane, pentaerythritol, and glycerin. Examples of the epoxy group-containing compound include triglycidyl tris (2-hydroxyethyl) isocyanurate, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl. Examples include ether, phenol (EO) 5 glycidyl ether, pt-butylphenyl glycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, glycidyl methacrylate, and butyl glycidyl ether. Moreover, the same effect can be acquired by alloying the polymer containing an epoxy group.

  These reactive compounds are used as one or a mixture of two or more, usually added in an amount of 0.5 to 80 parts by weight, preferably 0.5 to 70 parts by weight with respect to 100 parts by weight of the base resin. If this blending amount exceeds 80 parts by weight, workability and film forming property during preparation of the adhesive may be lowered.

  In the present invention, when the adhesive resin composition is a thermosetting type, an organic peroxide is blended as a curing agent, and this organic peroxide decomposes at a temperature of 70 ° C. or higher to generate radicals. Any material can be used as long as it has a decomposition temperature of 50 ° C. or more, with a half-life of 10 hours, film formation temperature, preparation conditions, curing (bonding) temperature, heat resistance of adherend, storage It is selected in consideration of stability.

Examples of usable organic peroxides include 2,5-dimethylhexane, 2,5-dihydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne 3, and di- t-butyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide, α, α′-bis (t-butylperoxy) Isopropyl) benzene, n-butyl-4,4′-bis (t-butylperoxy) valerate, 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy)- 3,3,5-trimethylcyclohexane, t-butyl peroxybenzoate, benzoyl peroxide, t-butyl peroxyacetate, methyl ethyl ketone -Oxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, butyl hydroperoxide, p-menthane hydroperoxide, p-chlorobenzoyl peroxide, hydroxyheptyl peroxide, chlorohexanone peroxide, octanoyl peroxide Oxide, decanoyl peroxide, lauroyl peroxide, cumyl peroxy octoate, succinic acid peroxide, acetyl peroxide, t-butyl peroxy (2-ethylhexanoate), m-toluoyl peroxide, t- Examples thereof include butyl peroxyisobutyrate and 2,4-dichlorobenzoyl peroxide. These organic peroxides may be used alone or in combination of two or more.

  Such an organic peroxide is preferably blended in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the base resin.

  In the present invention, when the adhesive resin composition is a photocurable type, a photosensitizer that generates radicals by light is blended. As the photosensitizer (photopolymerization initiator), radical light is used. A polymerization initiator is preferably used. Among radical photopolymerization initiators, benzophenone, methyl o-benzoylbenzoate, 4-benzoyl-4′-methyldiphenyl sulfide, isopropylthioxanthone, diethylthioxanthone, ethyl 4- (diethylamino) benzoate and the like as hydrogen abstraction type initiators. It can be used. Among radical photopolymerization initiators, benzoin ether, benzoylpropyl ether, benzyldimethyl ketal as an intramolecular cleavage type initiator, and 2-hydroxy-2-methyl-1-phenylpropane-1 as an α-hydroxyalkylphenone type -One, 1-hydroxycyclohexyl phenyl ketone, alkylphenylglyoxylate, diethoxyacetophenone, also as α-aminoalkylphenone type, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopro Panone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 and acylphosphine oxide are used. These photosensitizers may be used alone or in combination of two or more.

  Such a photosensitizer is preferably blended in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the base resin.

  It is preferable to add a silane coupling agent as an adhesion promoter to the adhesive resin composition. As silane coupling agents, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Propyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ -1 type, or 2 or more types of mixtures, such as aminopropyl trimethoxysilane, is used.

  The amount of these silane coupling agents added is usually 0.01 to 5 parts by weight per 100 parts by weight of the base resin.

  In addition, a hydrocarbon resin can be added to the adhesive resin composition for the purpose of improving processability and bonding property. In this case, the added hydrocarbon resin may be either a natural resin type or a synthetic resin type. In the natural resin system, rosin, rosin derivatives, and terpene resins are preferably used. For rosin, gum-based resins, tall oil-based resins, and wood-based resins can be used. As the rosin derivative, rosin obtained by hydrogenation, heterogeneity, polymerization, esterification, or metal chloride can be used. As the terpene resin, a terpene phenol resin can be used in addition to a terpene resin such as α-pinene and β-pinene. Moreover, you may use danmaru, koval, and shellac as another natural resin. On the other hand, in the synthetic resin system, petroleum resin, phenol resin, and xylene resin are preferably used. As the petroleum resin, aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin, copolymer petroleum resin, hydrogenated petroleum resin, pure monomer petroleum resin, and coumarone indene resin can be used. As the phenol resin, an alkyl phenol resin or a modified phenol resin can be used. As the xylene-based resin, a xylene resin or a modified xylene resin can be used.

  Although the addition amount of such a hydrocarbon resin is appropriately selected, it is preferably 1 to 200 parts by weight, more preferably 5 to 150 parts by weight with respect to 100 parts by weight of the base resin.

  In addition to the above additives, an anti-aging agent, an ultraviolet absorber, a dye, a processing aid and the like may be used in the adhesive resin composition according to the present invention as long as the object of the present invention is not impaired.

The anisotropic conductive film of the present invention is obtained by dispersing the above-mentioned conductive particles in such an adhesive resin composition. The adhesive resin composition containing the conductive particles preferably has a melt index (MFR) of 1 to 3000, particularly 1 to 1000, particularly 1 to 800, and a fluidity at 70 ° C. of 10 ⁵ Pa ·. It is preferable that the composition be selected so that such MFR and fluidity can be obtained.

  The anisotropic conductive film of the present invention is prepared by uniformly mixing the adhesive resin composition component and the conductive particles in a predetermined composition, kneading with an extruder, a roll, etc., and then calendering roll, T-die extrusion, It can be manufactured by forming a film in a predetermined shape by a film forming method such as inflation. Alternatively, the adhesive resin composition and conductive particles can be dissolved or dispersed in a solvent, applied to the surface of the separator, and then evaporated to evaporate the solvent. In the film formation, embossing may be performed for the purpose of preventing blocking and facilitating pressure bonding with the adherend.

  There is no restriction | limiting in particular in the thickness of this invention, Although it determines suitably according to a use purpose, Usually, it is about 10-100 micrometers.

  In order to adhere the adherends to each other with the anisotropic conductive film thus obtained, for example, a bonding method using a hot press, an extruder, a direct laminating method using a calendar, a thermocompression bonding method using a film laminator, etc. Various techniques can be used.

  As the curing conditions in the anisotropic conductive film of the present invention, in the case of thermosetting, depending on the type of organic peroxide used, it is usually 70 to 170 ° C., preferably 70 to 150 ° C., usually 10 seconds to 120 seconds, preferably 20 to 60 seconds.

  In the case of photocuring using a photosensitizer, many light sources that emit light in the ultraviolet to visible region can be used as a light source, such as ultra-high pressure, high pressure, low pressure mercury lamp, chemical lamp, xenon lamp, halogen lamp, Mercury halogen lamp, A carbon arc lamp, an incandescent lamp, a laser beam, etc. are mentioned. The irradiation time cannot be determined unconditionally depending on the type of lamp and the intensity of the light source, but it is about several tens of seconds to several tens of minutes.

  In order to accelerate curing, the laminate may be preheated to 40 to 120 ° C. and irradiated with ultraviolet rays.

  At the time of bonding, it is preferable to apply a pressure of about 1 to 4 MPa, particularly about 2 to 3 MPa in the bonding direction.

The anisotropic conductive film of the present invention has a conductivity of 10 Ω or less, particularly 5 Ω or less in the film thickness direction, and the resistance in the plane direction is preferably 10 ⁶ Ω or more, particularly 10 ⁹ Ω or more. .

  The anisotropic conductive film of the present invention is suitable for connecting, for example, FPC or TAB and an ITO terminal on a glass substrate of a liquid crystal panel, but can also be used for other purposes, and can be used for the above-described base resin during curing. A cross-linked structure is formed, and high adhesion, excellent durability, and heat resistance are obtained.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

  In addition, the load value at the time of 30% compression of the conductive particles used in the following examples and comparative examples was 0.23 gf / sec with a load speed of 0.23 gf / sec, a test load using a Shimadzu micro compression tester “PCT-200 type”. 3 gf is a value obtained by measuring a load at the time of 30% deformation when compressive deformation is performed on one particle.

Moreover, the connection resistance value of an anisotropic conductive film and the measuring method of insulation are as follows.
[Measurement method of connection resistance]
An anisotropic conductive film is attached between an FPC electrode and an ITO electrode having a circuit pitch of 50 μm by a four-terminal method, and heat-pressed at 130 ° C. for 20 seconds at 3 MPa, and between the electrodes of the conductive particles contained in the anisotropic conductive film. The connection resistance value was measured, and when the connection resistance value was less than 1000 mΩ, the conduction characteristics were good, and when the connection resistance value was 1000 mΩ or more, the conduction characteristics were poor.
[Measurement method of insulation]
An anisotropic conductive film is pasted between a comb electrode substrate having a circuit pitch of 50 μm and a glass substrate, heat-pressed at 130 ° C. for 20 seconds and 3 MPa, and a DC voltage of 100 V is applied between adjacent terminals for 1 minute to insulate. The resistance value was measured, and a resistance value of 10 ⁶ Ω or more was regarded as good insulation, and a resistance value of less than 10 ⁶ Ω was regarded as poor insulation.

Examples 1 to 4, Comparative Examples 1 and 2
Conductive particle-containing adhesive resin compositions were prepared with the formulations shown in Table 1, respectively. Each of these adhesive resin compositions was prepared by first preparing a 25 wt% toluene solution of the base resin, and then mixing each component in the ratio shown in Table 1 with respect to the base resin.

  After this adhesive resin composition was applied onto poly (ethylene terephthalate) as a separator, toluene was evaporated to obtain a film having a width of 5 mm and a thickness of 40 μm.

  Each anisotropic conductive film was measured for connection resistance and insulation, and the results are shown in Table 2. Table 2 also shows the type of base resin used, the average particle diameter of the conductive particles, and the load value at 30% compression.

  From Table 2, according to the anisotropic conductive film of the present invention using conductive particles having an average particle size and a load value at 30% compression within a predetermined range, while obtaining excellent conduction characteristics in the thickness direction, It can be seen that good insulation can be obtained in the surface direction.

Claims (8)

In an anisotropic conductive film formed by forming an adhesive resin composition in which conductive particles are dispersed,
An anisotropic conductive film, wherein the conductive particles satisfy the following conditions (1) and (2):
(1) The load value at 30% compression is 0.100 to 0.600 gf when compressively deforming one particle at a load speed of 0.23 gf / sec and a test load of 3 gf.
(2) Average particle size is 2-7μm   The anisotropic conductive film according to claim 1, wherein the amount of the conductive particles is 0.1 to 15% by volume with respect to the base resin in the adhesive resin composition.   The modified polyacetalization according to claim 1 or 2, wherein the adhesive resin composition comprises a polyacetalized resin obtained by acetalizing polyvinyl alcohol and / or an aliphatic unsaturated group introduced into a side chain of the polyacetalized resin. An anisotropic conductive film, which is a thermosetting or photocurable resin composition containing a base resin made of a resin.   3. The adhesive resin composition according to claim 1, wherein the adhesive resin composition is a thermosetting or photocurable resin composition containing a base resin mainly composed of a polyester unsaturated compound soluble in a solvent. Anisotropic conductive film.   5. The adhesive resin composition according to claim 1, wherein the adhesive resin composition contains 0.1 to 10 parts by weight of an organic peroxide or a photosensitizer with respect to 100 parts by weight of the base resin. An anisotropic conductive film.   6. The adhesive resin composition according to claim 1, wherein the adhesive resin composition is selected from the group consisting of an acryloxy group-containing compound, a methacryloxy group-containing compound, and an epoxy group-containing compound with respect to 100 parts by weight of the base resin. An anisotropic conductive film comprising 0.5 to 80 parts by weight of a reactive compound.   The anisotropic conductive material according to any one of claims 1 to 6, wherein the adhesive resin composition contains 0.01 to 5 parts by weight of a silane coupling agent with respect to 100 parts by weight of the base resin. the film.   The anisotropic conductive film according to any one of claims 1 to 7, wherein the adhesive resin composition contains 1 to 200 parts by weight of a hydrocarbon resin with respect to 100 parts by weight of the base resin.