JP6249818B2 - Cationic polymerizable resin composition, method for producing the same, and bonded structure - Google Patents

Description

  The present invention relates to a cationic polymerizable resin composition, a method for producing the same, and an adhesive structure.

  Conventionally, a cationic polymerizable resin composition mainly composed of an epoxy group-containing compound or the like has been used as an adhesive for connecting circuit boards and circuit components. In addition, for the purpose of improving productivity such as an increase in the curing rate at a low temperature, it has also been proposed to add a latent thermal acid generator to the cationic polymerizable resin composition (see Patent Documents 1 and 2).

  However, the cationic polymerizable resin composition to which the latent thermal acid generator is added has a feature that the curing is quick even at a low temperature. On the other hand, the viscosity increases with the lapse of time after the addition of the curing agent. Therefore, the conventional cationic polymerizable resin composition has the drawbacks that the pot life is very short and the workability is poor.

JP 2011-207948 A JP 2011-032353 A

  An object of the present invention is to provide a cationically polymerizable resin composition having a high workability with an extended pot life without inhibiting a curing rate in a cationically polymerizable resin composition having a latent thermal acid generator as a curing agent. It is to provide.

  As a result of intensive studies in view of the above circumstances, the present inventor has obtained a specific quaternary phosphonium salt and a latent thermal acid other than the quaternary phosphonium salt in a cationic polymerizable resin composition containing a compound having an epoxy group. It has been found that the pot life can be extended without inhibiting the curing rate by using the generator in combination with a specific mass ratio, and the present invention has been completed.

  That is, the present invention is a cationic polymerizable resin composition comprising a compound having an epoxy group, a quaternary phosphonium salt represented by the following formula (1), and a latent thermal acid generator other than the quaternary phosphonium salt. A cationically polymerizable resin composition having a mass ratio of the quaternary phosphonium salt / latent thermal acid generator other than the quaternary phosphonium salt of 0.001 to 1.

(Wherein R ₁ , R ₂ , R ₃ and R ₄ may be the same group or different groups, each independently represents an alkyl group or a phenyl group, and X ⁻ represents an anion. Represents.)
In addition, the present invention is an adhesive structure characterized by using a cationically polymerizable resin composition as an adhesive.

  ADVANTAGE OF THE INVENTION According to this invention, the cationically polymerizable resin composition with the high workability | operativity which extended the pot life can be provided, without inhibiting a cure rate.

Hereinafter, the present invention will be described in detail.
The cationically polymerizable resin composition of the present invention contains an epoxy group-containing compound, a quaternary phosphonium salt, and a latent thermal acid generator other than the quaternary phosphonium salt as essential components.

  The compound having an epoxy group used in the present invention is not particularly limited as long as it is generally used in an adhesive for connecting electronic components, and is usually a compound having two or more epoxy groups in one molecule. Specific examples of such compounds include novolak resins such as phenol novolak and cresol novolak, polyhydric phenols such as bisphenol A, bisphenol F, bisphenol AD, resorcin, and bishydroxydiphenyl ether, ethylene glycol, neopentyl glycol, glycerin, Reaction of polychlorohydric alcohols such as trimethylolpropane and polypropylene glycol, polyamino compounds such as ethylenediamine, triethylenetetramine and aniline, polyhydric carboxy compounds such as adipic acid, phthalic acid and isophthalic acid, and epichlorohydrin or 2-methylepichlorohydrin. Aliphatic epoxy resins such as glycidyl type epoxy resin, dicyclopentadiene epoxide, butadiene dimer epoxide obtained by ', Alicyclic epoxy resins such as 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate. These epoxy resins may be used alone or in combination of two or more. For these epoxy resins, it is preferable to use a high-purity product in which impurity ions (Na, Cl, etc.), hydrolyzable chlorine, etc. are reduced, in order to prevent ion migration. An alicyclic epoxy resin is preferable from the viewpoints of high adhesive strength, excellent heat resistance and electrical insulation, low melt viscosity, and connection at low pressure. Furthermore, when the alicyclic epoxy resin is used alone and cationically polymerized, the heat generated by the reaction is rarely large and the resin itself may be altered by heat. It is more preferable to use an epoxy resin in combination. In this case, it is preferable that the alicyclic epoxy resin and the glycidyl type epoxy resin have a mass ratio of 99: 1 to 25:75 from the viewpoint that the curing rate becomes slow as the content of the glycidyl type epoxy resin increases. .

  When an epoxy resin having a high viscosity or a solid epoxy resin is used, the viscosity may be lowered using a reactive diluent. The reactive diluent is not particularly limited as long as it is reactive to the ring-opening polymerization of the epoxy resin and can reduce the viscosity. Specific examples of the reactive diluent include n-butyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, p-sec-butylphenyl glycidyl ether, glycidyl methacrylate, Examples include t-butylphenyl glycidyl ether, diglycidyl ether, (poly) ethylene glycol glycidyl ether, butanediol glycidyl ether, trimethylolpropane triglycidyl ether, 1,6-hexanediol diglycidyl ether, and the like. These reactive diluents may be used alone or in combination of two or more. For these reactive diluents, it is preferable to use a high-purity product in which impurity ions (such as Na and Cl) and hydrolyzable chlorine are reduced, in order to prevent ion migration.

  The quaternary phosphonium salt used in the present invention is represented by the following formula (1). By using this quaternary phosphonium salt as a curing catalyst together with a latent thermal acid generator other than the quaternary phosphonium salt described later, the effect of extending the pot life while maintaining the curing rate can be obtained.

In the formula (1), R ₁ , R ₂ , R ₃ and R ₄ may be the same group or different groups, and each independently represents an alkyl group or a phenyl group (—C ₆ H ₅ ). When R < ₁ > -R < ₄ > in Formula (1) is an alkyl group, a C1-C16 alkyl group is preferable.
In Formula (1), X ⁻ represents an anion, for example, F ⁻ , Cl ⁻ , I ⁻ , Br ⁻ , SO ₄ ²⁻ , BF ₄ ⁻ , PF ₄ ⁻ , SbF ₆ ⁻ , (OC _2). H ₅ ) ₂ P═O ⁻ , (C ₆ H ₅ ) ₄ B ^{— and the} like.

  In the present invention, the quaternary phosphonium salt may be solid or liquid. Further, the quaternary phosphonium salt may be diluted or dissolved with a general organic solvent. Examples of organic solvents include alcohols, polyhydric alcohols and derivatives thereof, aromatic hydrocarbons, esters, ketones, glycol ethers, chlorinated organic solvents, chlorofluorocarbon organic solvents, petroleum organic solvents, and others. And special organic solvents. These organic solvents may be used alone or in combination of two or more. Tertiary phosphine is dangerous in handling because it is rapidly oxidized in the air and has pyrophoric properties. If imidazole, which is a general curing aid, is used instead of the quaternary phosphonium salt, the curing time is greatly inferior.

  The quaternary phosphonium salt in the present invention can be synthesized by obtaining a quaternary phosphonium halide by a nucleophilic reaction between a tertiary phosphine compound and an alkyl halide, and exchanging the quaternary phosphonium halide with a desired anion. .

  A commercial item can be used as the quaternary phosphonium salt in the present invention. As such a commercial item, for example, trade name: Hishicolin (registered trademark) series grade name: PX-2B (Tetraethylphosphonium bromide) manufactured by Nippon Chemical Industry Co., Ltd. Grade name: PX-2C (tetraethyl) Grade name: PX-4B (Tetra-n-butylphosphonium bromide), Grade name: PX-4C (Tetra-n-butylphosphonium chloride), Grade name: PX-4I (tetrabutylphosphonium iodide), grade name: PX-48B (n-Octyltri-n-butylphosphonium bromide), grade name: PX-4ET (tetrabutylphosphonium bromide) Tetra-n-butylphosphonium o, o-diethylphosphorodithioate), grade name: PX-4BT (Tetra-n-butylphosphonium benzotriazolate), grade name: PX-4MI (Methyltri-n-butylphosphoniumiodide), Grade name: PX-2H (Tetraethylphosphoniumhydroxide), Grade name: THPS (Tetrakis (hydroxymethyl) phosphoniumsulfate) , Grade name: PX-4FB (Tetrabutylphosphonium tetrafluoroborate), Grade name: PX-4PB (Tetrabutylphosphonium tetraphenylborate (Tetra) -n-butylphosphoniumtetraphenylborate)), Grade name: PX-4FP (Tetra-n-butylphosphoniumhexafluorophosphate), Grade name: PX-412B (n-Dodecyltri-n-butylphosphoniumbromide)) Grade name: PX-412C (n-Dodecyltri-n-butylphosphonium chloride), Grade name: PX-416B (Hexadecyltri-n-butylphosphonium bromide), Grade name: PX -416C (hexadecyltributylphosphonium chloride), grade name: MTPPBr (Methyltriphenylphosphonium bromide), grade name ETPPBr (Ethyltriphenylphosphonium bromide), Grade name: ETPPI (Ethyltriphenylphosphoniumiodide), Grade name: BTPPBr (Triphenylbutylphosphonium bromide), Grade name: BzTP Benzyltriphenylphosphonium bromide, grade name: BzTPPCCl (Benzyltriphenylphosphonium chloride), grade name: PX-23B (Triethylpropylphosphonium bromide), grade name: PX-25B (triethylpentyl) Phosphonium bromide (Triethylpentylphosphoniumbromide) Grade name: PX-2BZC (Triethylbenzylphosphonium chloride), Grade name: PX-4BZC (Tributylbenzylphosphonium chloride), Grade name: PX-4BZB (Tributylbenzylphosphonium bromide), Grade name : PX-42B (Tributylethylphosphonium bromide), Grade name: PX-43B (Tributylpropylphosphonium bromide), Grade name: PX-45B (Tributylpentylphosphonium bromide), Grade name: PX -46B (Tributylhexylphosphonium bromide ), Grade name: PX-48B (Tributyloctylphosphonium bromide), Grade name: PX-48C (Tributyloctylphosphonium chloride), Grade name: PX-4AlC (Tributylallylphosphonium chloride), Grade name: PX-4AlB (Tributylallylphosphonium bromide), Grade name: PX-4MP (Methyltri-n-butylphosphonium dimethylphosphate), Grade name: PX-8MP (Methyltrioctylphosphonium dimethyl phosphate) (Methyltrioctylphosphoniumdimethylphosphate)) and the like. Among these, methyltributylphosphonium dimethyl phosphate and methyltrioctylphosphonium dimethyl can be effectively extended with the addition of a small amount, while maintaining the rapid curability of the latent thermal acid generator. Phosphate is preferred.

  The amount of the quaternary phosphonium salt as a curing catalyst in the cationic polymerizable resin composition of the present invention is determined with respect to the amount of the latent thermal acid generator other than the quaternary phosphonium salt described later, and the quaternary phosphonium salt / 4. The mass ratio of the latent thermal acid generator other than the secondary phosphonium salt is 0.001-1. When the mass ratio of the latent thermal acid generator other than the quaternary phosphonium salt / quaternary phosphonium salt is less than 0.001, the effect of extending the pot life cannot be obtained. On the other hand, when the mass ratio exceeds 1, although the effect of extending the pot life can be obtained, the gelation time becomes long, and there is a problem that curing is difficult to occur. The mass ratio of the latent thermal acid generator other than the quaternary phosphonium salt / quaternary phosphonium salt is preferably 0.005 to 0.8, more preferably 0.01 to 0.7.

  The latent thermal acid generator other than the phosphonium salt used in the present invention may be a compound that can generate a cationic species or a Lewis acid by heating, for example, an aromatic sulfonium salt, a thiophenim salt, a thiolanium salt, Examples include benzylammonium, pyridinium salt, hydrazinium salt, carboxylic acid ester, sulfonic acid ester, and amine imide. Of these, aromatic sulfonium salts are preferred because the compounds are relatively stable and cure quickly when mixed with an epoxy resin.

Commercial products can be used as latent thermal acid generators other than phosphonium salts in the present invention. Examples of such commercially available products include San-Aid (registered trademark) series SI-L85, SI-L110, SI-L145, SI-L160, SI-H15, SI-H20, SI manufactured by Sanshin Chemical Industry Co., Ltd. -H25, SI-H40, SI-H50, SI-60L, SI-80L, Sun-Aid SI-100L, Sun-Aid SI-80, Sun-Aid SI-100, TA-60, TA-100, TA-110 manufactured by Sun Apro Co., Ltd. Adeka Opton CP-66 (counter ion: SbF ₆ ), Adeka Opton CP-77, KINGINDUSTRISIN INC. Manufactured by ADEKA Corporation. TAG-2678, TAG-2713, TAG-2172, 3M FC-520 manufactured by Nippon Soda Co., Ltd., CI-2921, CI-2920, CI-2946, CI-3128, CI-2624, CI-2623 CI-2064 and the like. These latent thermal acid generators may be used alone or in combination of two or more.

  The amount of the latent thermal acid generator other than the quaternary phosphonium salt in the cationic polymerizable resin composition of the present invention is preferably 0.1% by mass to 10% by mass, more preferably 0%, based on the epoxy resin. .2 mass% to 5 mass%. If the content of the latent thermal acid generator other than the quaternary phosphonium salt is more than 10% by mass relative to the epoxy resin, the pot life may be shortened. On the other hand, if the content of the latent thermal acid generator other than the quaternary phosphonium salt is less than 0.1% by mass, the curing rate may be slow.

  A known additive can be added to the cationic polymerizable resin composition of the present invention as long as the pot life and the curing rate are not affected. Known additives include, for example, silane coupling agents, organic solvents, fillers, thixotropic agents, thickeners, thickeners, conductive agents, leveling agents, antioxidants, tackifiers, waxes, and heat stabilizers. Agent, anti-stabilizer, foaming agent, organic pigment, inorganic pigment, thermal conductive agent, electrical conductive agent, dye, antistatic agent, moisture-permeable factory agent, water repellent, hollow foam, flame retardant colorant, water absorbing agent, In addition to hygroscopic agents, deodorants, foam stabilizers, antifoaming agents, antifungal agents, antiseptics, algaeproofing agents, pigment dispersants, antiblocking agents, hydrolysis inhibitors, etc., organic water-soluble compounds, inorganic water-soluble compounds Other resins such as compounds, thermoplastic resins, and thermosetting resins can be used in liquid or solid form. Representative of additives are electrical conductors, thermal conductors and thixotropic agents.

  In the present invention, as the electrical conductive agent, metal particles such as nickel, gold, silver, palladium, copper, and solder, those having conductivity by themselves such as carbon particles, or a metal film on the surface of the core material particles Conductive particles having formed thereon can be used.

  The particle size of the conductive particles is appropriately selected according to the specific use of the cationic polymerizable resin composition of the present invention. In the present invention, the cationic polymerizable resin composition is used as an adhesive for electronic circuit connection. When the particle size is too small, conduction between the counter electrodes cannot be performed. On the other hand, when the particle size of the conductive particles is too large, a short circuit occurs between adjacent electrodes. The average particle size is preferably 0.1 μm to 1000 μm, more preferably 0.5 to 100 μm, as a value measured using an electric resistance method.

  The shape of the conductive particles is not particularly limited. In general, the conductive particles may be in the form of powder, but may have other shapes, for example, a fiber shape, a hollow shape, a plate shape, or a needle shape, and have a large number of protrusions on the particle surface, or an irregular shape. It may be. Among these, spherical conductive particles are particularly preferable in terms of excellent filling properties.

  The conductive particles having a metal film formed on the surface of the core material particles will be further described. There are no particular limitations on the core particles that can be used, regardless of whether they are inorganic or organic. Inorganic core particles include metal particles such as gold, silver, copper, nickel, palladium, solder, alloys, glass, ceramics, silica, metal or non-metal oxides (including hydrates), and aluminosilicates. Examples thereof include metal silicate, metal carbide, metal nitride, metal carbonate, metal sulfate, metal phosphate, metal sulfide, metal acid salt, metal halide and carbon. Examples of organic core material particles include thermoplastic resins such as natural fibers, natural resins, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polybutene, polyamide, polyacrylic ester, polyacryl nitrile, polyacetal, ionomer, and polyester. Alkyd resin, phenol resin, urea resin, benzoguanamine resin, melamine resin, xylene resin, silicone resin, epoxy resin, diallyl phthalate resin and the like.

  The shape of the core material particles is not particularly limited. In general, the core particles may be in the form of powder, but may have other shapes, for example, a fiber shape, a hollow shape, a plate shape, or a needle shape, have a large number of protrusions on the particle surface, or have an irregular shape. It may be. Among these, when the spherical core material particles are conductive particles, it is particularly preferable in that the filling property is excellent.

  The average particle size of the core particles is preferably 0.1 μm to 1000 μm, and more preferably 0.5 μm to 100 μm. If the average particle size of the core particles is too small, there may be cases where conduction between the counter electrodes cannot be performed even with conductive particles having a metal film formed thereon. On the other hand, if the average particle size of the core particles is too large, a short circuit between adjacent electrodes may occur. In addition, the average particle diameter of core material particle | grains shows the value measured using the electrical resistance method.

Furthermore, there is a range in the particle size distribution of the core particles measured by the method described above. In general, the width of the particle size distribution of the powder is represented by a coefficient of variation represented by the following calculation formula (1).
Coefficient of variation (%) = (standard deviation / average particle size) × 100 (1)
A large coefficient of variation indicates that the distribution is wide, while a small coefficient of variation indicates that the particle size distribution is sharp. It is preferable to use core particles having a coefficient of variation of 50% or less, preferably 30% or less, particularly preferably 20% or less. This is because, when used as conductive particles in an anisotropic conductive film, there is an advantage that the effective contribution ratio for connection is increased.

Further, the other physical properties of the core material particles are not particularly limited, but in the case of the core material particles made of a resin material, the following calculation formula (2):
K (kgf / mm ² ) = (3 / √2) × F × S−3 / 2 × R−1 / 2 (2)
[In Formula (2), F and S are respectively the load value (kgf) and the compression displacement (mm in 10% compression deformation of the core particles when measured with a micro compression tester (MCTM-500 manufactured by Shimadzu Corporation). R is the radius (mm) of the core material particles measured with a micro compression tester (MCTM-500 manufactured by Shimadzu Corporation)] and the value of K defined by 10 kgf / mm ^{2 at} 20 ° C. What is in the range of 10,000 kgf / mm ² and the recovery rate after 10% compression deformation is in the range of 1% to 100% at 20 ° C. does not damage the electrodes when crimping the electrodes, It is preferable at the point which can fully contact.

  As a method of forming a metal film on the surface of the core particle, there are a dry method using a vapor deposition method, a sputtering method, a mechanochemical method, a hybridization method, a wet method using an electroplating method, an electroless plating method, etc. Can be mentioned. Moreover, you may form a metal membrane | film | coat on the surface of core material particle | grains combining these methods. As a method of forming a metal film on the surface of the core particles, a vapor deposition method, a sputtering method, a mechanochemical method, a dry method using a hybridization process, a wet method such as an electrolytic plating method, an electroless plating method, or the like A method combining these can be used.

  In the present invention, the conductive particles may be one or two of metal particles such as gold, silver, copper, nickel, palladium and solder, or gold, silver, copper, nickel, palladium and solder on the surface of the core particles. It is preferable to use conductive particles formed with a metal film of more than one kind. In particular, the conductive plated particles in which the metal film is formed on the surface of the core material particles by the electroless plating method have a uniform and dense metal film surface. It is preferable in that it is coated. Particularly, those using resin as core material particles are less likely to settle due to their lower specific gravity than metal powder, increase dispersion stability, and maintain electrical connection due to the elasticity of the resin. It is preferable at such points. The metal film alloy (for example, nickel-phosphorus alloy or nickel-boron alloy) is also included.

  As the conductive particles, coated conductive particles obtained by coating the surfaces of the conductive particles with an insulator can be used. By coating the particle surface of the conductive powder with insulating inorganic fine particles, aggregation of the particles can be suppressed and storage stability can be improved.

  Examples of the thermal conductive agent include boron nitride, aluminum oxide, titanium oxide, and silica. These may be used singly or in combination of two or more. Further, the particle shape, size, and addition amount are not particularly limited.

  The cationically polymerizable composition of the present invention can be obtained by mixing the above-described components using a general apparatus. Examples of such an apparatus include a planetary mixer, two rolls, three rolls, a bead mill, a ball mill, and the like, but are not particularly limited as long as they can make one liquid uniform. A self-revolving vacuum degassing stirrer is suitable because it can simultaneously knead and remove bubbles in the paste in a short time.

  The order in which the components are added during the kneading is not particularly limited, but when a latent thermal acid generator other than the quaternary phosphonium salt is added directly to the epoxy resin, the latent thermal acid generator other than the quaternary phosphonium salt and the epoxy are added. The reaction may start at the moment of contact with the resin. Therefore, when the latent thermal acid generator other than the quaternary phosphonium salt is added, the latent thermal acid generator other than the quaternary phosphonium salt is added to the epoxy resin in which the quaternary phosphonium salt which is a pot life extender is previously contained. It is preferable that a latent thermal acid generator other than the quaternary phosphonium salt and the quaternary phosphonium salt are made into a uniform solution in advance. At this time, as long as the latent thermal acid generator other than the quaternary phosphonium salt and the quaternary phosphonium salt as the pot life extender are not affected, common organic solvents such as alcohols, polyhydric alcohols and the like Derivatives thereof, aromatic hydrocarbons, esters, ketones, glycol ethers, chlorinated organic solvents, chlorofluorocarbon organic solvents, petroleum organic solvents, and other special organic solvents may be used. These organic solvents may be used alone or in combination of two or more.

  The cationically polymerizable resin composition thus obtained can be used without worrying about the pot life, for example, in what is desired to be bonded at 60 ° C. to 150 ° C. for several seconds. Useful for making adhesive structures. Further, when electrically conductive particles are added to the cationic polymerizable resin composition of the present invention, it becomes an anisotropic conductive adhesive, and particularly an adhesive for electronic materials used to electrically connect circuit boards and circuit components to each other. Suitable as an agent.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

<Synthesis of methyltributylphosphonium dimethyl phosphate>
Under a nitrogen environment, 100 g of tributylphosphine as a tertiary phosphine was heated to 60 ° C., and 45 g of a 30 ° C. trimethyl phosphate solution was dropped over 12 hours. After completion of dropping, the mixture was aged at 60 ° C. for 24 hours. After aging, measurement was performed by ion chromatography, and after confirming that tributylphosphine was completely consumed by the reaction, the obtained transparent liquid was washed twice with hexane, dried while heating under vacuum, and methyltributylphosphonium dimethyl. 90 g of phosphate was obtained.

<Synthesis of methyltrioctylphosphonium dimethyl phosphate>
Under a nitrogen environment, 100 g of trioctylphosphine, which is a tertiary phosphine, was heated to 60 ° C., and 45 g of a 30 ° C. trimethyl phosphate solution was added dropwise over 12 hours. After completion of dropping, the mixture was aged at 60 ° C. for 24 hours. After aging, it was measured with an ion chromatograph, and after confirming that tributylphosphine was completely consumed by the reaction, the obtained transparent liquid was washed twice with hexane, dried while heating under vacuum, and methyltrioctylphosphonium. 90 g of dimethyl phosphate was obtained.

<Examples 1-9>
The amounts of epoxy resin, viscosity modifier and quaternary phosphonium salt shown in Table 1 were kneaded at 2000 rpm for 15 minutes with a self-revolving vacuum defoaming stirrer to give a mixed solution. Thereafter, the latent thermal acid generator of the amount shown in Table 1 was added to the obtained mixed liquid, and further kneaded with a self-revolving vacuum defoaming stirrer at 2000 rpm for 15 minutes to obtain a cationic polymerizable resin composition. It was. The obtained resin composition was a transparent and viscous liquid.

<Example 10>
The latent thermal acid generator and quaternary phosphonium salt in the amounts shown in Table 1 were kneaded with a self-revolving vacuum degassing stirrer at 2000 rpm for 15 minutes to obtain a mixed solution. Thereafter, the epoxy resin and the viscosity modifier in the amounts shown in Table 1 were added to the obtained mixed liquid, and further kneaded at 2000 rpm for 15 minutes with a self-revolving vacuum defoaming stirrer to obtain a cationic polymerizable resin composition. It was. The obtained resin composition was a transparent and viscous liquid.

  In Tables 1 and 2, epoxy resin A is an alicyclic epoxy resin (manufactured by Daicel Corporation, trade name: Celoxide (registered trademark) CEL2012P), and epoxy resin B is a bisphenol A type epoxy resin (Mitsubishi Chemical Corporation). Company name, product name: jER828), viscosity modifier manufactured by Nippon Aerosil Co., Ltd., product name: Aerosil (registered trademark) 200, latent thermal acid generator A is aromatic sulfonium salt (Sanshin Chemical Co., Ltd.) Product name: Sun-Aid (registered trademark) SI-60L), latent thermal acid generator B is an aromatic sulfonium salt (manufactured by Sanshin Chemical Co., Ltd., product name: Sun-Aid (registered trademark) SI-80L). ) The quaternary phosphonium salt A is methyltributylphosphonium dimethyl phosphate synthesized above, and the quaternary phosphonium salt B is methyl synthesized above. Trioctylphosphonium dimethyl phosphate, imidazole, Shikoku Chemicals Co., Ltd., product name: Curezol (registered trademark), which is a 2E4MZ.

<Comparative Examples 1 and 2>
The epoxy resin and viscosity modifier in the amounts shown in Table 2 were kneaded at 2000 rpm for 15 minutes with a self-revolving vacuum defoaming stirrer to give a mixed solution. Thereafter, the latent thermal acid generator of the amount shown in Table 2 was added to the obtained mixed liquid, and further kneaded at 2000 rpm for 15 minutes with a self-revolving vacuum degassing stirrer to obtain a cationically polymerizable resin composition. It was. The obtained resin composition was a transparent and viscous liquid.

<Comparative Example 3>
The amounts of epoxy resin, viscosity modifier and quaternary phosphonium salt shown in Table 2 were kneaded at 2000 rpm for 15 minutes with a self-revolving vacuum defoaming stirrer to give a mixed solution. Thereafter, the latent thermal acid generator of the amount shown in Table 2 was added to the obtained mixed liquid, and further kneaded at 2000 rpm for 15 minutes with a self-revolving vacuum degassing stirrer to obtain a cationically polymerizable resin composition. It was. The obtained resin composition was a transparent to white liquid.

<Comparative Example 4>
The amount of epoxy resin shown in Table 2, the viscosity modifier, and imidazole as a curing aid were kneaded with a self-revolving vacuum degassing stirrer at 2000 rpm for 15 minutes to obtain a mixed solution. Thereafter, the latent thermal acid generator of the amount shown in Table 2 was added to the obtained mixed liquid, and further kneaded at 2000 rpm for 15 minutes with a self-revolving vacuum degassing stirrer to obtain a cationically polymerizable resin composition. It was. The obtained resin composition was a transparent and viscous liquid.

<Measurement of pot life>
About the cationically polymerizable resin compositions of Examples 1 to 10 and Comparative Examples 1 to 4, the viscosity at 25 ° C. was measured using a rheometer MARS II manufactured by Thermo Fisher Scientific Co., Ltd. It was measured.
This resin composition was kept at a constant temperature of 35 ° C., and the viscosity was measured every 24 hours. The time until the viscosity reaches twice the viscosity immediately after preparation of the resin composition was defined as the pot life, and the results are shown in Table 3.

<Measurement of gelation time>
For the cationic polymerizable resin compositions of Examples 1 to 10 and Comparative Examples 1 to 4, 0.2 g of the resin composition was placed on a hot plate at 150 ° C., and the time (seconds) until gelation was measured while stirring. . The results are shown in Table 3.

<Peel adhesion strength (90 degree peel test)>
For the cationically polymerizable resin compositions of Examples 1 to 10 and Comparative Examples 1 to 4, an aluminum foil of 200 mm × 200 mm × 0.05 μm was placed on a hot plate at 150 ° C., and the resin composition 2 g and a thickness of 0. A spacer was placed so as to be 2 mm, and a stainless steel plate of 200 mm × 200 mm × 2 mm was placed thereon and held for 10 minutes for adhesion. After cooling to room temperature, the aluminum foil side was slit to a width of 25 mm, and the aluminum foil was pulled up in the direction of 90 degrees at a speed of 50 mm per minute. As a result, in the cationic polymerizable resin compositions of Examples 1 to 10 and Comparative Examples 1 and 2, equivalent peel adhesion strength was obtained. On the other hand, the cationic polymerizable resin compositions of Comparative Examples 3 and 4 could not be measured because they were not cured.

  From the above results, the cationic polymerizable resin compositions of Examples 1 to 10 in which the quaternary phosphonium salt and the latent thermal acid generator other than the quaternary phosphonium salt were blended at a specific mass ratio have a short gel time. Until now, it was confirmed that a pot life of 48 hours or more could be secured even if kept at 35 ° C.

<Preparation of anisotropic conductive adhesives of Examples 11 to 20 and Comparative Examples 5 to 6>
5 g of metal-coated resin particles (manufactured by Nippon Chemical Industry Co., Ltd., trade name: Bright 20GNR4.6-EH) are added to 95 g of the cationic polymerizable resin composition obtained in Examples 1 to 10 and Comparative Examples 1 and 2. Then, the anisotropic conductive adhesive was obtained by kneading with a self-revolving vacuum degassing stirrer at 2000 rpm for 15 minutes.

<Measurement of pot life and gelation time>
About the anisotropic conductive adhesive of obtained Examples 11-20 and Comparative Examples 5-6, the pot life and gelation time were evaluated by the method similar to an above-mentioned pot life measurement and gelation time measurement. The results are shown in Table 4.

<Measurement of resistance value>
Using the anisotropic conductive adhesives of Examples 11 to 20 and Comparative Examples 5 to 6, dummy ICs were mounted on an Al wiring board at 140 ° C., 8 seconds, and 1.5 N. The mounted substrate with IC was measured by the two-terminal method. The results are shown in Table 4.

  In the anisotropic conductive adhesives of Examples 11 to 20, the gelation time remains short, and even when kept at 35 ° C., a working time of 48 hours or more can be secured, and the connection resistance value is low. It was confirmed that

Claims (9)

A cationically polymerizable resin composition comprising a compound having an epoxy group, a quaternary phosphonium salt represented by the following formula (1), and an aromatic sulfonium salt ,
A cationically polymerizable resin composition having a mass ratio of the quaternary phosphonium salt / the aromatic sulfonium salt of 0.001 to 1.

(Wherein R ₁ , R ₂ , R ₃ and R ₄ may be the same group or different groups, each independently represents an alkyl group or a phenyl group, and X ⁻ represents an anion. Represents.)   The cationically polymerizable resin composition according to claim 1, wherein the quaternary phosphonium salt is methyltributylphosphonium dimethyl phosphate or methyltrioctylphosphonium dimethyl phosphate.   The cationic polymerizable resin composition according to claim 1, wherein the compound having an epoxy group includes a compound having an alicyclic epoxy group. The cationically polymerizable resin composition according to any one of claims 1 to 3 , further comprising conductive particles. 5. The cationically polymerizable resin composition according to claim 4 , wherein the conductive particles are metal particles selected from the group consisting of nickel, gold, silver, palladium, copper, and solder. The cationically conductive resin composition according to claim 4 , wherein the conductive particles are particles in which a metal film is formed on the surface of the core material particles by an electroless plating method. The cationic polymerization according to any one of claims 1 to 3 , wherein the aromatic sulfonium salt is added to and mixed with a mixed solution containing the compound having an epoxy group and the quaternary phosphonium salt. For producing a conductive resin composition. The cationic polymerization according to any one of claims 1 to 3 , wherein the compound having the epoxy group is added to and mixed with a mixed solution containing the quaternary phosphonium salt and the aromatic sulfonium salt. For producing a conductive resin composition. An adhesive structure using the cationic polymerizable resin composition according to any one of claims 1 to 6 as an adhesive.