JP4395350B2 - Curable resin composition and conductive adhesive - Google Patents

Description

  The present invention relates to a polyimide silicone resin / epoxy resin-based curable resin composition containing conductive metal powder, and a conductive adhesive containing the curable resin composition.

  Conventionally, when a light emitting diode (LED) component or a laser diode (LD) component is manufactured by a lamp type, SMD (surface mount component) type, or the like, in order to bond the LED chip or the LD chip and the lead frame, A conductive epoxy resin adhesive is used. In particular, when an assembly of an LED chip or an LD chip and a lead frame is exposed to a high temperature state in the wire bonding process, a polyfunctional epoxy resin that gives a heat-resistant cured product is employed as a binder for the adhesive. ing.

  Recently, LEDs have been used for a wide range of applications such as automobiles, traffic lights, electric bulletin boards, etc., because they have a long service life and high response speed, and are expected to expand further in the future. Yes. Moreover, since energy efficiency is extremely high compared with conventional lighting fixtures such as a light bulb and a fluorescent lamp, it is expected that LEDs are practically used for illumination. LDs are expected to be used more and more for optical recording applications and communication applications.

  It is anticipated that it will be necessary to use high brightness LED components for lighting applications. In order to maintain sufficient brightness for illumination, it is necessary that a current several times as large as that of the conventional general-purpose LED is continuously supplied to the high-luminance LED component for a long time. In addition, with higher recording density and higher communication speed, LDs are required to have higher output and shorter wavelengths, and are more stable at higher temperatures and longer usage conditions than conventional LDs. There is a need for something that works.

Therefore, the LED chip or LD chip generates heat, and the LED component or LD component is exposed to a high temperature state for a long time. When the LED component or the LD component is manufactured using the conventional epoxy resin adhesive, the adhesive layer gradually deteriorates due to insufficient heat resistance of the adhesive layer over time. There is a possibility that the performance of the LD component cannot be maintained and the reliability is lowered.
In addition, when manufacturing the said LED component or LD component, using a polyimide silicone resin was not known.

  The object of the present invention is to provide a cured product having a low specific resistance, high adhesive strength, excellent thermal conductivity, and a cured product excellent in heat resistance and durability with little change over time in the high temperature state of these characteristics. It is to provide a resin composition and a conductive adhesive containing the curable resin composition. In particular, the present invention is to provide the conductive adhesive that is suitable for the production of high-brightness LED components or LD components and can form a cured adhesive layer having excellent heat resistance, heat dissipation, and thermal conductivity.

  As a result of intensive studies to achieve the above object, the present inventors have excellent heat resistance and durability of various physical properties by combining an epoxy resin and a polyimide silicone resin having a curing reactive group. The knowledge that a cured product can be obtained was obtained, and the present invention was completed based on the knowledge.

  That is, the present invention includes (A) containing a polyimide silicone resin having two or more phenolic hydroxyl groups in one molecule, (B) an epoxy resin, and (C) a conductive metal powder. The present invention provides a curable resin composition to be used, and a conductive adhesive containing the curable resin composition.

  The composition of the present invention is useful as a conductive adhesive, and its cured product satisfies the characteristics of high heat resistance and high thermal conductivity that are indispensable for practical use of high-brightness LEDs or LDs for lighting applications. Yes, the heat generated from the LED chip or LD chip is effectively transmitted to the lead frame to dissipate it, and the initial performance can be maintained even when exposed to high temperature for a long time. .

Hereinafter, the present invention will be described in detail.
First, the curable resin composition of the present invention will be described.

[(A) Polyimide silicone resin]
The polyimide silicone resin of component (A) of the composition of the present invention has two or more phenolic hydroxyl groups in one molecule, and this is a feature of the present invention. And this (A) component can unite with the epoxy resin of the below-mentioned component (B), can form hardened | cured material, and can provide heat resistance and durability to the said hardened | cured material. The component (A) is preferably soluble in an organic solvent and colorless and transparent.

  The component (A) of the present invention can be obtained by a method similar to the known synthesis of polyimide. That is, it is obtained by reacting (x) a tetracarboxylic acid or a derivative thereof such as a monoanhydride, dianhydride, monoester or diester (hereinafter referred to as “tetracarboxylic acid component”) with (y) a diamine compound. be able to.

(x) Tetracarboxylic acid component The tetracarboxylic acid component used for preparing the polyimide silicone resin of component (A) of the present invention is not particularly limited, and all those conventionally used for the synthesis of polyimide are used. can do.
Preferred examples thereof include those having the structure shown below.

この(x)成分のテトラカルボン酸成分は、１種単独でも２種以上を組み合わせても使用することができる。

The tetracarboxylic acid component of component (x) can be used alone or in combination of two or more.

(y) Diamine Compound For the preparation of the component (A) of the present invention, for example, a combination of at least two diamine compounds is used as the (y) diamine compound to be reacted with the tetracarboxylic acid component of the component (x). Must be used. That is, it is necessary to use (y1) a diamine compound having two or more phenolic hydroxyl groups and (y2) a diamine compound having a siloxane structure. In addition, (y3) diamine compounds other than (y1) and (y2) may be used in combination.

  Alternatively, in place of the two types of diamine compounds (yi) and (y2), a diamine compound having a siloxane structure together with at least two phenolic hydroxyl groups may be used. A polyimide silicone resin can be prepared.

<(Y1) Diamine Compound Having Phenolic Hydroxyl Group>
The diamine compound as the component (y1) is a diamine compound having a phenolic hydroxyl group and having two or more hydroxyl groups. The two or more hydroxyl groups are substituted and bonded to the same or different aromatic rings.

Here, in this specification, the phenolic hydroxyl group is a structure in which a hydrogen atom bonded to a carbon atom forming an aromatic ring skeleton of an aromatic hydrocarbon or an aromatic hydrocarbon group is substituted with a hydroxyl group. The hydroxyl group is meant.
The component (y1) is preferably the following general formula (3):

（式中、Ａは単結合または２価の有機基である）
で表されるジアミン化合物が挙げられる。

(In the formula, A is a single bond or a divalent organic group)
The diamine compound represented by these is mentioned.

Examples of the divalent organic group in the above formula include —CH ₂ —, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, —SO ₂ — and the like.
Preferable specific examples of the diamine compound represented by the general formula (3) include those having the structure shown below.

この(y1)成分は、１種単独でも２種以上を組み合わせても使用することができる。

This component (y1) can be used alone or in combination of two or more.

<(Y2) Diamine Compound Having Siloxane Structure>
The diamine compound as the component (y2) has at least one siloxane bond (Si—O—Si) in its structure.
The component (y2) is preferably the following general formula (4):

（式中、Ｒは独立に炭素原子数１〜６の１価炭化水素基であり、ａは１〜120、好ましくは１〜60の整数である）
で表されるジアミン化合物が挙げられる。

(In the formula, R is independently a monovalent hydrocarbon group having 1 to 6 carbon atoms, and a is an integer of 1 to 120, preferably 1 to 60).
The diamine compound represented by these is mentioned.

R in the above formula (4) is, for example, an alkyl group such as methyl group, ethyl group, propyl group, isopropyl group, isobutyl group, butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group; cyclopentyl Groups, cycloalkyl groups such as cyclohexyl groups; alkenyl groups such as vinyl groups, allyl groups, propenyl groups, isopropenyl groups, butenyl groups, isobutenyl groups, hexenyl groups; cycloalkenyl groups such as cyclohexenyl groups; aryls such as phenyl groups; Groups and the like. Among these, a methyl group and a phenyl group are preferable from the viewpoint of easy availability of raw materials.
In addition, the a is preferably an integer in the above range in order not to reduce the adhesion of the cured product of the present invention to the substrate.

  Preferable specific examples of the diamine compound represented by the general formula (4) include those having the structure shown below.

この(y2)成分は、１種単独でも２種以上を組み合わせても使用することができる。

This component (y2) can be used alone or in combination of two or more.

<(Y3) Diamine compound other than (y1) and (y2) >
Examples of the component (y3) include the following general formula (5):

（式中、Ｂは２価の有機基である）
で表されるエーテル結合を有するジアミン化合物が挙げられる。
上記式(5)中のＢとしては、例えば、下記の２価の有機基が挙げられる。

(Wherein B is a divalent organic group)
The diamine compound which has an ether bond represented by these is mentioned.
Examples of B in the above formula (5) include the following divalent organic groups.

上記一般式(5)で表されるジアミン化合物の好適な具体例としては、下記に示す構造を有するものが挙げられる。

Preferable specific examples of the diamine compound represented by the general formula (5) include those having the structure shown below.

この(y3)成分は、１種単独でも２種以上を組み合わせても使用することができる。

This component (y3) can be used alone or in combination of two or more.

<Use ratio of diamine compound>
As described above, in the preparation of the polyimide silicone resin that is the component (A) of the composition of the present invention, when the diamine compound (y1), (y2), and optionally (y3) is used, the above (A) In order to impart curability to the component polyimide silicone resin and to ensure sufficient adhesion, strength and elasticity with the substrate of the cured product of the composition of the present invention, the above (y1), (y2) and (y3 ), The diamine compound having a phenolic hydroxyl group is usually 10 to 80 mol%, preferably 20 to 60 mol%, and the siloxane structure (y2) The diamine compound is usually 5 to 50 mol%, preferably 10 to 45 mol%, and the diamine compound other than the above (y3) (y1) and (y2) is usually 1 to 50 mol%, preferably 5 It may be used in combination as an amount in the range of ˜40 mol%.

<Preparation of (A) polyimide silicone resin>
The polyimide silicone resin which is the component (A) of the composition of the present invention is an approximately equimolar amount of the (x) tetracarboxylic acid component and the (y) diamine compound (mixture) according to a known polyimide synthesis method. It can be prepared by using and reacting. Specifically, it can be prepared by a one-stage polymerization method under high temperature reaction conditions. In addition, the above components (x) and (y) are dissolved in a solvent such as cyclohexanone or N-methyl-2-pyrrolidone and reacted at a relatively low temperature (about 10 to 50 ° C.) to form a polyamic which is a polyimide precursor. An acid can be obtained and then prepared by a two-stage polymerization method in which dehydration and cyclization is carried out under high temperature conditions to form an imide ring structure.

  Here, the use ratio of the (y) diamine compound (mixture) to 1 mol of the (x) tetracarboxylic acid component can be appropriately determined according to the setting of the desired molecular weight of the polyimide silicone resin. The range is 10.5 mol, preferably 0.98 to 1.02 mol.

  In addition, you may add components, such as dicarboxylic acids, such as phthalic anhydride, and monoamines, such as aniline, as a molecular weight regulator to the said reaction system. The addition amount in this case is preferably 2 mol% or less with respect to the total number of moles of the above components (x) and (y).

  The conditions for the single-stage polymerization method are a reaction temperature of 150 to 300 ° C. and a reaction time of about 1 to 15 hours. Moreover, as a condition in the case of the two-stage polymerization method, the polymic acid synthesis step is performed at a reaction temperature of 0 to 120 ° C. and a reaction time of about 1 to 100 hours, and then the obtained polyamic acid solution is usually used. The polyimide resin solution can be obtained by raising the temperature to a temperature range of 80 to 200 ° C., preferably 140 to 180 ° C., and allowing the dehydration ring closure reaction to proceed for 1 to 15 hours. Further, a method of adding and mixing a mixed solution of acetic anhydride and pyridine to the polyamic acid solution and then raising the temperature to about 50 ° C. to perform dehydration ring closure can be employed.

  When a solvent is used in the preparation of the above (A) polyimide silicone resin, the solvent may be any one that is compatible with the above-mentioned components (x) and (y). Examples of this solvent include phenols such as phenol, 4-methoxyphenol, 2,6-dimethylphenol, and m-cresol; ethers such as tetrahydrofuran and anisole; cyclohexanone, 2-butanone, methyl isobutyl ketone, and 2-heptanone. Ketones such as 2-octanone and acetophenone; esters such as butyl acetate, methyl benzoate and γ-butyrolactone; cellsolves such as butyl cellosolve acetate and propylene glycol monomethyl ether acetate; N, N-dimethylformamide, N, Examples include amides such as N-dimethylacetamide and N-methyl-2-pyrrolidone. These solvents can be used singly or in combination of two or more.

  In addition, by using each of the exemplified solvents together with aromatic hydrocarbons such as toluene and xylene, it is possible to facilitate removal of water produced during dehydration ring closure by azeotropic distillation.

  Even when two or more of the tetracarboxylic acid component (x) and the diamine compound (y) are used, the reaction method is not particularly limited. For example, all reaction raw materials May be a method in which all of the above are previously charged and mixed and then polymerized, or a method in which two or more kinds of reaction raw materials are individually and sequentially added to the reaction system.

  The component (A) polyimide silicone resin obtained by the above reaction is composed of a repeating unit (a), a repeating unit (b), and optionally a repeating unit (c) represented by the following formula (6): It is.

上記式中、Ｘは上記(x)成分に由来するテトラカルボン酸残基であり、例えば、下記で示される４価の基である。

In the above formula, X is a tetracarboxylic acid residue derived from the component (x), for example, a tetravalent group shown below.

  In the above formula, Y is a diamine residue derived from the component (y1), for example, a divalent group represented by the following general formula (1).

（式中、Ａは上記一般式(3)に関して定義のとおりである。）

(In the formula, A is as defined for the general formula (3)).

  In the above formula, Z is a diamine residue derived from the component (y2), for example, a divalent group represented by the following general formula (2).

（式中、Ｒおよびａは、上記一般式(4)に関して定義のとおりである。）

(In the formula, R and a are as defined for the general formula (4)).

  In the above formula, W is a diamine residue derived from the component (y3), for example, a divalent group represented by the following general formula (7).

（式中、Ｂは上記一般式(5)に関して定義のとおりである。）

(In the formula, B is as defined for the above general formula (5).)

  The proportion of the repeating units (a), (b) and (c) contained in the polyimide silicone resin of component (A) is substantially the same as the proportion of the diamine compound used in components (y1) to (y3). It is.

  The weight-average molecular weight of the component (A) polyimide silicone resin has good compatibility with other composition components such as a solvent, and the adhesiveness, strength and elasticity of the cured product of the composition of the present invention with the substrate are improved. In order to be sufficient, it is usually 5000-150,000, preferably 10,000-70,000.

[(B) Epoxy resin]
The epoxy resin of the component (B) of the composition of the present invention is a curable resin component that reacts with the phenolic hydroxyl group that the component (A) has in its structure, together with the component (A). It is a component that gives a cured product together.

  The epoxy resin as the component (B) may be a compound having two or more epoxy groups in one molecule. For example, phenol novolac type epoxy resin, cresol novolac type epoxy resin; bisphenol A type epoxy resin such as diglycidyl bisphenol A; bisphenol F type epoxy resin such as diglycidyl bisphenol F; triphenylalkane type such as triphenylpropane triglycidyl ether Epoxy resins; cycloaliphatic epoxy resins such as 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate; glycidyl ester resins such as diglycidyl phthalate, diglycidyl hexahydrophthalate, dimethyl glycidyl phthalate; bis [diglycidyl Aminophenyl] methane, triglycidyl-p-aminophenol, diglycidylaniline, diglycidyltoluidine, tetraglycidylbisaminomethylcyclo Examples thereof include glycidylamine resins such as hexane. These can be used singly or in combination of two or more.

  The blending amount of the epoxy resin of the component (B) is preferably an amount that does not decrease the strength of the cured product of the composition of the present invention, and is usually 0.1 to 30 parts by mass with respect to 100 parts by mass of the component (A). The range is preferably 5 to 20 parts by mass.

<Curing accelerator>
In the composition of the present invention, various curing accelerators may be used as necessary in order to promote the effective reaction of the epoxy resin as the component (B).

  Examples of the curing accelerator include organic phosphine compounds such as triphenylphosphine and tricyclohexylphosphine; trimethylhexamethylenediamine, diaminodiphenylmethane, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl). ) Amino compounds such as phenol and triethanolamine; imidazole compounds such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole and 2-phenyl-4,5-dihydroxymethylimidazole. These can be used singly or in combination of two or more. Among these, 2,4,6-tris (dimethylaminomethyl) phenol and 2-methylimidazole are preferable.

  When the curing accelerator is used, the blending amount is usually 10 parts by mass or less, preferably 0 to 5 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the component (B). is there. When there are too many said compounding quantities, the pot life of this invention composition may become short and it may be inferior to workability | operativity.

[(C) Conductive metal powder]
The conductive metal powder as the component (C) of the composition of the present invention is blended to impart conductivity to the cured product obtained from the composition of the present invention and to apply the composition of the present invention as a conductive adhesive. It is an ingredient.
Examples of the conductive metal powder of component (C) include metal powders such as silver, gold, copper, and nickel.

  Among these, silver powder is particularly preferably used because of its excellent electrical characteristics, thermal conductivity, and oxidation resistance performance. The shape of the silver powder is not particularly limited, and may be, for example, a granular shape, a dendritic shape, a flake shape, an indefinite shape, or a combination of silver powders having different shapes. The particle size of the silver powder is not particularly limited, but it is usually 0.05 to 100 μm, preferably 0.1 to 50 μm. The average particle size is usually in the range of 1 to 10 μm, preferably 2 to 8 μm. The shape, particle size, and average particle size of the silver powder are as follows, so that the tap density is high and the specific surface area (the same applies to the BET method hereinafter) is small. It is preferable because it can be highly filled into a product.

Aggregates between silver powders are difficult to aggregate, and as an indicator of the properties that can be present in a high density and high filling by uniformly dispersing in the above-mentioned components (A) and (B) as a matrix phase, tap density and specific surface area Is mentioned. The tap density of the silver powder used in the present invention is usually, 3.0 g / cm ³ or more, preferably 4.0~7.0g / cm ^3, more preferably a 5.0~6.5g / cm ^3. The specific surface area is usually, 2.0 m ² / g or less, preferably 0.05 to 1.0 m ² / g, more preferably 0.1~0.7m ² / g.
In addition, about the measuring method of the tap density of the silver powder in this invention, it is as a postscript.

  If the tap density of the silver powder is too low, it will be difficult to disperse silver with high density in the cured product of the composition of the present invention, and the thermal conductivity of the cured product will decrease. If the specific surface area of the silver powder is too large, the amount of the organic solvent used increases when the organic solvent is added to the composition of the present invention to form a paste, and the remaining organic solvent accompanying the silver powder further increases. Due to the increased amount, the conductive properties are reduced when applied as a conductive adhesive.

  Although the manufacturing method of the silver powder used by this invention is not specifically limited, For example, the electrolytic method, the grinding | pulverization method, the heat processing method, the atomizing method, the reduction method etc. are mentioned. Among these, the reduction method is preferable because a powder having a high tap density and a small BET specific surface area can be easily obtained by controlling the reduction method.

  In addition, you may grind | pulverize and use silver powder in the range with which the preferable numerical range which concerns on said tap density and specific surface area is satisfy | filled. The apparatus in the case of grind | pulverizing silver powder is not specifically limited, For example, well-known apparatuses, such as a stamp mill, a ball mill, a vibration mill, a hammer mill, a rolling roller, a mortar, are mentioned.

  The blending amount of the component (B) conductive metal powder is usually 400 to 3000 parts by mass, preferably 100 parts by mass with respect to 100 parts by mass of the component (A), in order to improve the conductivity and workability. It is good to set it as 500-2500 mass parts.

[Other ingredients]
In addition to the above-described components, it is optional to add other components to the composition of the present invention as necessary within a range that does not impair the object and effect of the present invention.

<Adhesion improver>
A monofunctional epoxy compound containing one epoxy group in one molecule and carbon functional silane may be added for the purpose of improving adhesion to the substrate. Examples include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and the like. These can be used singly or in combination of two or more. When using this component, the compounding quantity is about 0.5-2.0 mass parts normally with respect to 100 mass parts of said (A) component.

<Conductive material>
In addition, conductive materials other than the component (C) can be blended.
Examples of the conductive material include conductive carbon black, conductive zinc white, and white conductive titanium oxide.

  As the conductive carbon black, those commonly used for conductive rubber compositions can be used. For example, acetylene black, conductive furnace black (CF), super conductive furnace black (SCF), extra conductive Examples thereof include furnace black (XCF), conductive channel black (CC), furnace black and channel black that have been heat-treated at a high temperature of about 1500 ° C.

  Specifically, for example, acetylene black such as electrified acetylene black (trade name, manufactured by Electrochemical Co., Ltd.), Shaunigan acetylene black (trade name, manufactured by Shaunigan Chemical Co., Ltd.); Continex CF (trade name, Continental Carbon) , Vulcan C (trade name, manufactured by Cabot), etc .; Super-Conductive Furnace Black, such as Continex SCF (trade name, manufactured by Continental Carbon), Vulcan SC (trade name, manufactured by Cabot); Asahi HS-500 (trade name, manufactured by Asahi Carbon Co., Ltd.), Vulcan XC-72 (trade name, manufactured by Cabot Corp.) and other extra conductive furnace blacks; Kolux L (trade name, manufactured by Degussa Corp.) and other conductive channel blacks Named, also fur Ketchen black EC, which is a kind of the scan black (trade name, manufactured by Ketchen Black International Co., Ltd.), can also be used Ketchen black EC-600JD (same).

  Among these, acetylene black is particularly preferably used in the present invention because it has a low impurity content, has a developed secondary structure, and is excellent in conductivity. Further, the above-described ketjen black EC, ketjen black EC-600JD, etc., which have an extremely large specific surface area and exhibit excellent conductivity even at a low blending amount, can be preferably used.

Examples of white conductive titanium oxide include ET-500W (trade name, manufactured by Ishihara Sangyo Co., Ltd.). In this case, the basic composition is preferably TiO ₂ · SnO ₂ doped with Sb.

These conductive materials can be used singly or in combination of two or more.
When using this electroconductive material, the compounding quantity is 1-500 mass parts normally with respect to 100 mass parts of said (A) component, Preferably it is about 2-300 mass parts.

<(D) Organic solvent>
In the composition of the present invention, in order to dilute and uniformly mix the above components, and to improve workability when applied as a conductive adhesive, (D) an organic solvent may be blended. it can. The component (D) is preferably compatible with the components (A) and (B) and not reactive with the component (B).

  Specific examples of the component (D) include ethers such as tetrahydrofuran and anisole; ketones such as cyclohexanone, 2-butanone, methylisobutylketone, 2-heptanone, 2-octanone, and acetophenone; n-butylcarbi Esters such as tall acetate, butyl acetate, methyl benzoate, and γ-butyrolactone; cellosolves such as butyl cellosolve acetate and propylene glycol monomethyl ether acetate; N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2 -Amides such as pyrrolidone; aromatic hydrocarbons such as toluene and xylene. These can be used singly or in combination of two or more.

  Among the above, ketones, esters and cellosolves are preferable, and n-butyl carbitol acetate, γ-butyrolactone, propylene glycol monomethyl ether acetate and N-methyl-2-pyrrolidone are particularly preferable.

  When using the organic solvent of this component (D), the blending amount is set in consideration of the solubility of the resin component, the workability of the application process to the substrate, the thickness of the predetermined film, etc. However, the amount is usually 50 to 500 parts by mass, preferably 100 to 400 parts by mass with respect to 100 parts by mass of the component (A). In the storage, transportation, etc. of the composition of the present invention, for example, this component (D) is not blended, or only a small amount thereof is added to keep the concentration of the resin component etc. relatively high, and the coating step For example, a sufficient amount of component (D) may be added to dilute to a predetermined concentration.

[Conductive adhesive]
The composition of the present invention can be suitably used particularly as a conductive adhesive. Specifically, this conductive adhesive is used for applications such as IC die bonding, LCD upper and lower electrode bonding, bare chip mounting, TAB electrode bonding, and LED chip or LD chip bonding to a lead frame. Can be applied.

  The conductive adhesive is usually preferably in the form of a paste, a high-viscosity liquid, or a liquid that can be applied with a screen printing method. In order to obtain these predetermined forms, it can be designed mainly by adjusting the blending ratio of the components (A) to (C), blending a predetermined amount of the component (D), and the like.

  As a method for applying the conductive adhesive, generally, a step of forming an adhesive layer by coating, potting or dipping on the surface of an adherend (that is, a substrate), and then an adhesive member on the adhesive layer. The step of pressure bonding and the step of evaporating and curing the volatile component such as the component (D) in the adhesive layer by subsequent treatment under a predetermined temperature and time condition are included. In the step of forming the adhesive layer, an adhesive layer having a thickness of about 5 to 50 μm is usually formed depending on the intended performance.

  In the step of curing the adhesive layer, the curing conditions vary depending on the types and amounts of the components (A) and (B) and the presence or absence of the use of the curing accelerator, and are not particularly limited. However, it is usually about 80 to 300 ° C., preferably 100 to 250 ° C., and about 10 to 120 minutes. If the temperature is too low, the time required for curing becomes long, which is not practical. Conversely, if the temperature is too high, the adhesive member may be deteriorated. In addition, since the adhesive of the present invention uses a polyimide silicone resin that has been previously cyclized as the component (A), it is necessary for the cyclization of the polyamic acid as compared with the case where the adhesive contains a polyamic acid. For example, there is an advantage that a high temperature condition exceeding 300 ° C. is not necessary.

  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.

<Measuring method of tap density of silver powder>
First, weigh 100 g of silver powder and gently drop it into a graduated cylinder (diameter: 22 mm, volume: 100 ml) using a funnel. This graduated cylinder is set in a tap density measuring instrument (manufactured by Kodaira Seisakusho). After tapping 600 times at a drop distance of 20 mm and at intervals of 1 second, the volume of the compressed silver powder is measured. The tap density was calculated and obtained.

<Preparation Example 1>
In a flask equipped with a stirrer, a thermometer, and a nitrogen displacement apparatus, 88.2 g (0.2 mol) of (x) 4,4′-hexafluoropropylidenebisphthalic dianhydride and 400 g of N-methyl-2-pyrrolidone were added. Prepared.
Next, (y2) the following structural formula:

で表されるジアミノシロキサン 35ｇ（0.04モル）、(y1) 3,3'-ジヒドロキシ-4,4'-ジアミノビフェニル 17.4ｇ（0.08モル）および (y3) 2,2-ビス[4-(4-アミノフェノキシ)フェニル]プロパン 32.8ｇ（0.08モル）を、Ｎ-メチル-2-ピロリドン 100ｇに溶解させた溶液を、反応系の温度が 50℃を越えないように調節しながら、上記フラスコ内に滴下した。

(Y1) 3,3′-dihydroxy-4,4′-diaminobiphenyl 17.4 g (0.08 mol) and (y3) 2,2-bis [4- (4- A solution obtained by dissolving 32.8 g (0.08 mol) of aminophenoxy) phenyl] propane in 100 g of N-methyl-2-pyrrolidone was added dropwise to the flask while adjusting the temperature of the reaction system so that it did not exceed 50 ° C. did.

After completion of the dropwise addition, the mixture was further stirred at room temperature for 10 hours. Next, after attaching a reflux condenser with a moisture receiver to the flask, 50 g of xylene was added, the temperature was raised to 150 ° C. and the temperature was maintained for 6 hours, and a yellowish brown solution was obtained.
The yellow-brown solution thus obtained was cooled to 25 ° C. and then poured into methanol for precipitation. Subsequently, it filtered and the obtained solid content was dried and the reaction product was obtained. This is designated as polyimide silicone resin (I).

<Preparation Example 2>
The amount of diaminosiloxane used as the component (y2) described in Preparation Example 1 is changed from 35 g (0.04 mol) to 70 g (0.08 mol), and the component 2, ybis [4- (4 -Aminophenoxy) phenyl] propane The polyimide silicone resin (II) was obtained in the same manner as in Preparation Example 1 except that 32.8 g (0.08 mol) was changed to 16.4 g (0.04 mol).

[Example 1]
(A1) 100 parts by mass of the polyimide silicone resin (I) obtained in Preparation Example 1 above, 18 parts by mass of diglycidyl toluidine, and 230 parts by mass of n-butyl carbitol acetate are put into a milk beak and kneaded. A fluid solution (viscosity at 25 ° C .: 20 Pa · s) was obtained. Next, 900 parts by mass of silver powder having an average particle size of 2.9 μm, a tap density of 5.70 g / cm ³ , and a specific surface area (BET method) of 0.42 m ² / g is added to this solution and stirred to disperse uniformly. An off-white paste composition (viscosity at 25 ° C .: 100 Pa · s) was obtained. This is designated as conductive adhesive A.

[Example 2]
(A2) 100 parts by mass of the polyimide silicone resin (II) obtained in Preparation Example 2 above, 15 parts by mass of diglycidyl toluidine, and 230 parts by mass of n-butyl carbitol acetate are put into a milk beak and kneaded. A fluid solution (viscosity at 25 ° C .: 25 Pa · s) was obtained. Next, 1900 parts by mass of silver powder having an average particle diameter of 3.7 μm, a tap density of 5.50 g / cm ³ and a specific surface area (BET method) of 0.32 m ² / g is added to this solution and stirred to disperse uniformly. An off-white paste-like composition (viscosity at 25 ° C .: 90 Pa · s) was obtained. This is referred to as conductive adhesive B.

[Comparative Examples 1 and 2]
As Comparative Example 1, a commercially available high heat-resistant epoxy-based conductive adhesive (trade name: Sylbest P-2460, manufactured by Tokiki Chemical Laboratory Co., Ltd.) is used. This is designated as conductive adhesive C.
As Comparative Example 2, a commercially available silicone-based conductive adhesive (trade name: Sylbest P-2457, manufactured by Tokuru Chemical Laboratory Co., Ltd.) is used. This is designated as conductive adhesive D.

<Performance evaluation test method>
For each of the above conductive adhesives, the specific resistance, adhesive strength, and thermal conductivity were measured as follows.

Specific Resistance: Each of the above conductive adhesives was printed on a slide glass in a pattern of 5 mm × 10 mm by a screen printing method, and then treated under conditions of 180 ° C. × 1 hour to cure the adhesive layer. The thickness of the hardened layer was measured, and further, the electrodes were in contact with both ends in the longitudinal direction of the pattern, and the electrical resistance was measured. The specific resistance was calculated based on the measurement result.
In addition, the cured layer formed on the slide glass was heat-treated under conditions of 150 ° C. × 2000 hours, and the specific resistance of the layer after the heat treatment was determined in the same manner as described above.

Adhesive strength: Each conductive adhesive was applied on a 25 mm × 25 mm copper plate to a thickness of 10 μm. On this adhesive layer, a brass piece having a bottom of 2.8 mm × 2.5 mm (area: 7 mm ² ) and a height of 7 mm was stacked and pressure-bonded. Next, the adhesive layer was cured by heat treatment under conditions of 180 ° C. × 1 hour.

Using the test specimen thus obtained, a push-pull gauge was brought into contact with a position 1 mm high from the bottom of the 7 mm-high brass piece and pushed until the brass piece peeled off from the copper plate and fell down. The maximum value displayed on the push-pull gauge was read, and the adhesive strength (N / 7 mm ² ) was measured.
The test specimen was heat-treated at 150 ° C. for 2000 hours, and the adhesive strength was measured in the same manner as described above for the heat-treated specimen.

Thermal conductivity: Each conductive adhesive is poured into a cylindrical hole of a Teflon (trade name, manufactured by DuPont) plate, heat-treated under conditions of 180 ° C. × 1 hour, cured, and 10 mm × 1 mm in diameter. A test piece was prepared. About this test piece, the thermal diffusivity and specific heat capacity are measured using a laser flash method thermal constant measuring apparatus (manufactured by ULVAC-RIKO), and the thermal conductivity (W / (m · K)) is obtained from the measurement result. It was.
The above measurement results are shown in Tables 1-3.

[Evaluation]
(1) The conductive adhesives A and B, which are examples, show lower specific resistance values than the conductive adhesives C and D of the comparative example, and the change rate after the heat resistance durability test is also small. It can also be seen that a cured film excellent in heat resistance is formed.
(2) The conductive adhesives A and B, which are examples, all show a larger adhesive strength than the conductive adhesive D of the comparative example, and the rate of change after the heat and durability test is also small. Moreover, it turns out that the rate of change after a heat-resistant durability test is smaller than the electroconductive adhesive C of a comparative example, and forms the cured film excellent in adhesive strength and heat resistance.
(3) It can be seen that the conductive adhesives A and B, which are examples, each form a cured film having higher thermal conductivity than the conductive adhesives C and D of the comparative example.

  From the above results, the composition of the present invention has excellent conductivity, adhesiveness, thermal conductivity, and heat resistance as a conductive adhesive, and has excellent durability that does not degrade performance even after long-term use. It can be seen that it is. When the conductive adhesive is used for bonding a high-intensity LED component for illumination or an LED chip of an LD component or an LD chip and a lead frame, the LED component can prevent heat generated by continuous use for a long time. Therefore, it is considered that the initial performance can be sufficiently maintained.

Claims (8)

(A) The following formula (6):

(Where
X is a tetracarboxylic acid residue derived from a tetracarboxylic acid component,
Y is the following general formula (1):

(In the formula, A is a single bond, —CH ₂ —, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, or —SO ₂ —).
In the case where a plurality of A are present in the molecule of the component (A), these A are the same or different,
Z is the following general formula (2):

(Wherein R is independently a monovalent hydrocarbon group having 1 to 6 carbon atoms, and a is an integer of 1 to 120)
A divalent group represented by:
W is a diamine residue derived from a diamine compound other than a diamine compound having two or more phenolic hydroxyl groups and a diamine compound having a siloxane structure)
A polyimide silicone resin composed of a repeating unit (a), a repeating unit (b), and optionally a repeating unit (c), and having two or more phenolic hydroxyl groups in one molecule;
(B) an epoxy resin, and
(C) A curable resin composition comprising a conductive metal powder. In the component (A), the content of the repeating unit (a) is 10 to 80 mol%, the content of the repeating unit (b) is 5 to 50 mol%, and the repeating unit (c) 2. The curable resin composition according to claim 1, wherein the content is 1 to 50 mol%, wherein the total content of the repeating units (a) to (c) is 100 mol%. W is the following general formula (7):

(Where B is

And when there are a plurality of Bs in the molecule of component (A), these Bs are the same or different. )
The curable resin composition according to claim 1, which is a divalent group represented by the formula:   The said (C) component is silver powder, The curable resin composition of any one of Claims 1-3.   Furthermore, (D) Curable resin composition of any one of Claims 1-4 containing the organic solvent.   When the component (A) contains 100 parts by mass, the component (B) 0.1 to 30 parts by mass, the component (C) 400 to 3000 parts by mass, and the component (D), the component (D) The curable resin composition according to any one of claims 1 to 5, comprising 50 to 500 parts by mass. The curable resin composition according to any one of claims 1 to 6, which is used for producing a high-intensity light-emitting diode component or a laser diode component. Conductive adhesive containing a curable resin composition according to any one of claims 1-7.