TW202311441A - Electroconductive resin composition and cured product thereof - Google Patents

Abstract

Provided is an electroconductive resin composition that can cure at a temperature of 150 DEG C or less and has exceptional electroconductivity, adhesive strength, and solvent resistance after curing. An electroconductive resin composition containing at least 0.3-5 parts by mass of (B) a cationic initiator and 250-2,400 parts by mass of (C) electroconductive particles per 100 parts by mass of a cationically polymerizable compound (A) including (A-1) an alicyclic epoxy compound and (A-2) a rubber-modified epoxy resin, the content ratio of the alicyclic epoxy compound (A-1) being 20 mass% or greater in component (A) and the content ratio of the rubber-modified epoxy resin (A-2) being 0.4-15 mass% in component (A).

Description

Conductive resin composition and hardened product thereof

The present invention relates to a conductive resin composition and its cured product, more specifically, to a cation-curable conductive resin composition and its cured product.

Background technique Conventionally, a conductive resin composition is known in which a conductive filler is blended into a thermosetting resin. This kind of conductive resin composition has been used, for example, as a conductive adhesive for bonding electronic parts and printed wiring boards, and another example is used as a conductive permanent hole filling composition for embedding printed wiring boards The use of guide holes or through holes. This kind of conductive resin composition requires high temperature (for example, 170~200°C) for thermosetting, but circuit boards used in precision machines are generally not resistant to high temperatures, so conventional conductive resin compositions are applied to circuit boards Sometimes, there is a concern that problems may occur during hardening.

Furthermore, in recent years, from an economical point of view, depending on the application, a low-heat-resistant base material that is cheaper than polyimide with high heat resistance such as polyester or polycarbonate has begun to be used. hardened conductive resin composition.

In view of the above problems, Patent Document 1 discloses a composition of cationic polymer as a conductive composition that can be hardened at low temperature.

However, there is still room for improvement regarding electrical conductivity, adhesive strength, and solvent resistance. Prior art literature patent documents

Patent Document 1: International Publication No. 2000/46315

Summary of the invention The problem to be solved by the invention The present invention has been accomplished in view of the above, and its object is to provide a conductive resin composition and its cured product. The conductive resin composition can be cured at a temperature below 150° C. Excellent solvent properties. means to solve problems

The present invention includes the embodiments shown below. [1] A conductive resin composition comprising at least: cationically polymerizable compounds (A) and (B) cations including (A-1) alicyclic epoxy compound and (A-2) rubber-modified epoxy resin Initiator and (C) conductive particle; And, with respect to above-mentioned (A) 100 mass parts of cationic polymerizable compound, above-mentioned (B) cationic initiator is 0.3～5 mass parts, and above-mentioned (C) conductive particle is 250～ 2400 parts by mass; the content ratio of the above-mentioned alicyclic epoxy compound (A-1) in the (A) component is 20% by mass or more, and the above-mentioned rubber-modified epoxy resin (A-2) in the (A) component The content ratio is 0.4 to 15% by mass. [2] The conductive resin composition as described in [1], wherein the above-mentioned component (A) further contains (A-3) an oxetane compound, and the oxetane compound (A-3) is included in the component (A) The content ratio is 10 to 30% by mass. [3] The conductive resin composition according to [1] or [2], wherein the cationic initiator (B) is at least one selected from the group consisting of the following salts: (B-1) Salt composed of percite cation and antimony anion, (B-2) salt composed of percite cation and phosphorus hexafluoride anion, (B-3) salt composed of percite cation and tetrakis (pentafluorophenyl) borate anion , and (B-4) a salt composed of quaternary ammonium and borate anion. [4] A cured product of a conductive resin composition, which is a cured product of the conductive resin composition described in any one of [1] to [3]. [5] A multi-layer substrate, which is composed of a plurality of conductive layers and an insulating layer between the plurality of conductive layers, and at least one hole penetrating through the insulating layer is formed, and the hole is filled with the following [1] ] to [4], wherein the conductive layers located at both ends of the hole are electrically connected to each other through the cured product of the conductive resin composition. Invention effect

According to the present invention, a conductive resin composition and its cured product can be provided. The conductive resin composition can be cured at a temperature below 150° C. and has excellent conductivity, adhesive strength and solvent resistance after curing.

form for carrying out the invention As mentioned above, the conductive resin composition of the present invention is made as follows: at least containing: (A-1) alicyclic epoxy compound and (A-2) cationic polymerizable compound (A-2) rubber-modified epoxy resin ), (B) cationic initiator and (C) conductive particle; The amount of conductive particles is 250 to 2400 parts by mass; the content ratio of the above-mentioned alicyclic epoxy compound (A-1) in the component (A) is 20% by mass or more, and the above-mentioned rubber-modified epoxy resin (A-2) is (A) The content ratio in a component is 0.4-15 mass %.

The cationically polymerizable compound (A) is not particularly limited as long as it is a compound having at least one cationically polymerizable group such as epoxy group, oxetanyl group, vinyl ether group, phenoxy group, etc. From the viewpoint of curing time, curing temperature) or adhesiveness of the cured product, a compound having two or more cationic polymerizable groups is preferable.

The cationic polymerizable compound (A) can be solid or liquid at 25°C, but from the viewpoint of coating properties, it is preferably liquid at 25°C, and when its viscosity is measured with a cone-plate viscometer, its The viscosity is more preferably 100~10000mPa･s. In addition, when using what is solid at 25 degreeC as a cationic polymerizable compound (A), the viscosity can be adjusted by adding a solvent. Here, the term "solid" refers to a substance that does not have fluidity in a solvent-free state, and the so-called "liquid" refers to a substance that has fluidity in a solvent-free state.

The alicyclic epoxy compound (A-1) is not particularly limited as long as it is a compound having at least one epoxycyclohexane ring or epoxycyclopentane ring. temperature) or the adhesiveness of the cured product, a compound having two or more epoxycyclohexane rings or epoxycyclopentane rings is preferable. Specific examples include: (3,3',4,4'-diepoxy)bicyclohexyl ((3,3',4,4'-diepoxy)bicyclohexyl), 3',4'-epoxy Hexylmethyl 3,4-epoxycyclohexane carboxylate, 1,2:5,6-bicyclononadiene diepoxide, and the like. For such compounds, commercially available products can also be used, for example, "CELLOXIDE (registered trademark) 2021P" manufactured by DAICEL Co., Ltd., "EPOCHALIC (registered trademark) THI-DE" manufactured by ENEOS Co., Ltd., DAICEL Co., Ltd. "EHPE3150" etc. These may be used individually by 1 type, and may use 2 or more types together.

The content ratio of the alicyclic epoxy compound (A-1) is not particularly limited as long as it is 20% by mass or more in the component (A), but from the viewpoint of curability, it is preferably 30 to 99% by mass, or more. Preferably it is 35-80 mass %, More preferably, it is 40-80 mass %.

The epoxy equivalent of the alicyclic epoxy compound (A-1) is not particularly limited, but is preferably 50-500 g/eq, more preferably 70-300 g/eq. When the epoxy equivalent of the alicyclic epoxy compound (A-1) is 50g/eq or more, it is easy to obtain excellent adhesive strength, and when the epoxy equivalent of the alicyclic epoxy compound (A-1) is 500g/eq or less , easy to obtain excellent low temperature hardening.

The weight average molecular weight of the alicyclic epoxy compound (A-1) is not particularly limited, but is preferably 1 million to 100,000. Here, the term "weight average molecular weight" in this specification refers to a value that can be measured by gel permeation chromatography (GPC), using tetrahydrofuran as a mobile phase, and based on a calibration curve converted into polystyrene. value.

As the rubber-modified epoxy resin (A-2), a compound obtained by reacting a homopolymer or copolymer compound having a reactive terminal with an epoxy compound can be used.

The homopolymeric or copolymeric compound having a reactive terminal is not particularly limited, but is preferably nitrile rubber (NBA) or carboxyl-terminated butadiene acrylonitrile rubber (CTBN).

The epoxy compound is not particularly limited as long as it is a compound having at least one epoxy group, but examples include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin Resin and other bisphenol-type epoxy resins; spiro-ring epoxy resins; naphthalene-type epoxy resins; biphenyl-type epoxy resins; terpene-type epoxy resins; ginseng (glycidoxy phenyl) methane; Glycidyl ether type epoxy resins such as glycidoxy phenyl) ethane; glycidyl amine type epoxy resins such as tetraglycidyl diaminodiphenylmethane; tetrabromobisphenol A type Epoxy resins, cresol novolak-type epoxy resins, phenol novolac-type epoxy resins, α-naphthol novolac-type epoxy resins, brominated phenol novolak-type epoxy resins, and other novolak-type epoxy resins.

For the above compounds, commercially available products can also be used, for example, "ADEKARESIN (registered trademark) EPR4030" manufactured by ADEKA Co., Ltd., "EPICLON (registered trademark) TSR-960" manufactured by DIC Corporation, " Hypox RA840", etc. A product may contain an unreacted epoxy compound corresponding to (A-1) component or (A-4) component mentioned later. That is, for example, when using a compound called "CTBN modified epoxy resin" which is a reaction product of bisphenol A type epoxy resin and carboxyl-terminated butadiene acrylonitrile rubber (CTBN), it is possible to prepare a CTBN modified ring The mixture of epoxy resin and unreacted bisphenol A epoxy resin, CTBN modified epoxy resin is equivalent to (A-2) component, unreacted bisphenol A epoxy resin is equivalent to (A-4) component.

The content ratio of the rubber-modified epoxy resin (A-2) is not particularly limited as long as it is 0.4 to 15% by mass in the component (A), but is preferably 0.4 to 8.0% by mass.

The epoxy equivalent of the rubber-modified epoxy compound (A-2) is not particularly limited, but is preferably 100-800 g/eq, more preferably 200-600 g/eq. When the epoxy equivalent of the rubber-modified epoxy compound (A-2) is 100g/eq or more, it is easy to obtain excellent adhesive strength, and when the epoxy equivalent of the rubber-modified epoxy compound (A-2) is 800g/eq or less , easy to obtain excellent low temperature hardening.

The weight average molecular weight of the rubber-modified epoxy compound (A-2) is not particularly limited, but is preferably 2 million to 100,000.

The cationically polymerizable compound (A) may further contain an oxetane compound (A-3). The oxetane compound is not particularly limited as long as it has one or more oxetane rings, for example: 3-ethyl-3-hydroxymethyl oxetane, 3-ethyl- 3-(phenoxymethyl)oxetane, 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene, bis(3-ethyl -3-Oxycyclobutanylmethyl) ether, etc. As such a compound, a commercially available product can also be used, for example, "ARONEOXETANE (registered trademark) OXT-121" or "ARONEOXETANE (registered trademark) OXT-221" manufactured by Toagosei Co., Ltd. is mentioned.

Although the content ratio of an oxetane compound (A-3) is not specifically limited, It is preferable that it is 10-30 mass % in (A) component, Preferably it is 10-20 mass %.

The oxetane equivalent of the oxetane compound (A-3) is not particularly limited, but is preferably 80 to 300 g/eq, more preferably 100 to 200 g/eq. When the oxetane equivalent of the oxetane compound (A-3) is 80 g/eq or more, it is easy to obtain excellent adhesive strength, and the oxetane equivalent of the oxetane compound (A-3) is 300 g/eq Below, excellent low-temperature curability can be easily obtained.

The weight average molecular weight of the oxetane compound (A-3) is not particularly limited, but is preferably 100-1000.

(A) A component may further contain epoxy compounds (A-4) other than the above. The epoxy compound (A-4) is not particularly limited as long as it is a compound having at least one epoxy group, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S Bisphenol-type epoxy resins such as epoxy resins; spiro-ring epoxy resins; naphthalene-type epoxy resins; biphenyl-type epoxy resins; terpene-type epoxy resins; ; Glycidyl ether type epoxy resins such as tetra(glycidoxy phenyl) ethane; Glycidyl amine type epoxy resins such as tetraglycidyl diaminodiphenylmethane; Tetrabromobis Phenol A-type epoxy resin, cresol novolak-type epoxy resin, phenol novolak-type epoxy resin, α-naphthol novolak-type epoxy resin, brominated phenol novolak-type epoxy resin, etc. novolak-type epoxy Resin; rubber modified epoxy resin, etc.

Although the content rate of other epoxy compounds (A-4) is not specifically limited, It is preferable that it is 0-75 mass % in (A) component, More preferably, it is 0-60 mass %.

Moreover, if the silane coupling agent etc. which are generally classified as an additive also have an epoxy group, it is considered to be included in (A-4) component.

In the present invention, a cationic initiator (B) is used to harden the cationic compound (A). The so-called cationic initiator (B) refers to one that uses heat or light to generate a strong acid to initiate the polymerization reaction of the cationic polymerizable compound.

Examples of the cationic initiator (B) include onium compounds represented by the following: amine salt of boron trifluoride, p-methoxybenzenediazonium hexafluorophosphate, diphenyliodonium hexafluorophosphate Phosphate, triphenylmalladium, tetra-n-butylphosphonium tetraphenylborate, tetra-n-butylphosphonium-o,o-diethyldithiophosphate.

The content of the cationic initiator (B) is not particularly limited as long as it is 0.3 to 5 parts by mass with respect to 100 parts by mass of the component (A), but is preferably 0.5 to 3 parts by mass. When the content of the cationic initiator (B) is 0.3 parts by mass or more, it can be fully cured at a temperature of 150° C. or lower, and it is easy to obtain excellent adhesive strength. When the content of the cationic initiator is 5 parts by mass or less, it is easy to obtain excellent storage stability and conductivity of the conductive resin composition.

The conductive particles (C) are not particularly limited as long as they are conductive particles, and examples thereof include copper particles, silver particles, nickel particles, silver-coated copper particles, gold-coated copper particles, silver-coated nickel particles, gold Coated nickel particles, solder particles (not only those composed of an alloy mainly composed of lead and tin but also those composed of so-called lead-free solder that does not contain lead) and the like.

The shape of electroconductive particle (C) is not specifically limited, Spherical shape, platelet shape, dendritic shape, etc. are mentioned. Here, the so-called dendritic shape refers to a shape having more than one dendritic protrusion protruding from the surface of the particle, and the dendritic protrusion may be only a main branch without branches, or may be branched from the main branch and have a planar shape. Or a shape that grows three-dimensionally.

Electroconductive particle (C) may be used individually by 1 type, and may use together 2 or more types from which shapes and materials differ.

The content of the conductive particles (C) is not particularly limited as long as it is 250 to 2400 parts by mass, but when the content of the solvent is less than 5 parts by mass relative to 100 parts by mass of the component (A), the content of the conductive particles (C) It is preferably 300 to 900 parts by mass, preferably 300 to 600 parts by mass. Moreover, when content of a solvent is 5-10 mass parts with respect to 100 mass parts of (A) components, content of electroconductive particle (C) is preferably 300-1900 mass parts, preferably 400-1500 mass parts. When content of electroconductive particle is 300 mass parts or more, the electroconductivity of hardened|cured material becomes favorable, and when it is 2400 mass parts or less, applicability becomes favorable easily.

The average particle diameter of the conductive particles (C) is preferably 0.5-30 μm. When the average particle size of the conductive particles is 0.5 μm or more, the dispersibility of the conductive particles is good, which prevents aggregation and is not easily oxidized. When the average particle size of the conductive particles is 30 μm or less, it is easy to obtain good adhesive strength.

In order to adjust the viscosity, the conductive resin composition of the present invention may also contain a solvent (D).

As the solvent used in the present invention, a volatile solvent that does not affect cationic polymerizability can be used, and examples thereof include ethers, acetals, and esters. Specifically, butyl carbitol, γ-butyrolactone, propylene carbonate, etc. are mentioned. These may be used individually by 1 type, and may use 2 or more types together. Furthermore, as for the compound affecting cationic polymerization, a compound having an alcohol group or a ketone group is exemplified.

The solvent content can be appropriately adjusted according to the properties of the component (A), the application of the conductive resin composition, the machine used for coating, and the like. The solvent content is usually at most 10 parts by mass, preferably at most 5 parts by mass, with respect to 100 parts by mass of the component (A), and it is more preferable not to use a solvent. When the solvent content is 10 parts by mass or less, it is easy to uniformly form a conductive resin composition layer on the object to be coated.

Furthermore, within the scope of not damaging the purpose of the invention, photosensitizers, chain transfer agents, fumed silica or cellulose nanometers for adjusting viscoelasticity can be added to the conductive resin composition of the present invention. Well-known additives such as fibers, defoamers, fillers, flame retardants, and colorants. The content of these additives can be appropriately selected according to the kind of the additive or its properties, and an approximate standard is 0 to 30 parts by mass with respect to 100 parts by mass of the (A) component.

As the chain transfer agent, alcohols or polyols can be used. The hardening speed of the conductive resin composition can be increased by compounding the chain transfer agent. As mentioned above, although the compound which has an alcohol group may affect cationic polymerization, it can also be added as a chain transfer agent within the range which does not impair the object of this invention.

The viscosity of the conductive resin composition of the present invention can be appropriately adjusted according to the coating method and application, but the approximate standard is preferably below 2000dPa･s, preferably below 1500dPa･s, more preferably below 800dPa･s. The viscosity of the conductive resin composition is a value measured using a cone-plate viscometer at 25° C. and a shear rate of 10 (1/sec).

The conductive resin composition of the present invention has excellent conductivity, adhesive strength, and solvent resistance, so it can be used as a conductive adhesive for bonding electronic parts and substrates, or as a hole filling for filling holes in printed wiring boards Composition with conductive resin.

If the conductive resin composition of the present invention is used as a conductive resin composition for hole filling, a multilayer substrate as shown in FIG. 1 can be obtained. Fig. 1 is a schematic enlarged sectional view showing an example of a multilayer substrate of the present invention. In FIG. 1, symbol 1 denotes a multilayer substrate, symbol 2 denotes an insulating layer, symbol 3 denotes a filler formed by hardening a conductive resin composition, and symbols L1 to L6 denote conductive layers.

In order to obtain the multilayer substrate 1 shown in this figure, for example, a drill or laser is used to form a hole in the insulating layer 2, and the hole is filled with a conductive resin composition 3 to form the conductive layers L1-L6, To stack layers. Then, it is sufficient to heat under predetermined conditions to harden the resin component. [Example]

Hereinafter, although the content of this invention is demonstrated in detail based on an Example, this invention is not limited to a following Example. In addition, unless otherwise stated below, "part" or "%" is a mass basis.

1. Preparation and evaluation of conductive resin composition [Example, comparative example] With respect to 100 parts by mass of the cationically polymerizable compound, a cationic initiator, conductive particles, and a solvent were prepared and mixed at the ratios described in Tables 1 to 5 to obtain a conductive resin composition. The details of the ingredients used are as follows.

˙Alicyclic epoxy compound 1: manufactured by DAICEL, trade name "CELLOXIDE (registered trademark) 2021P", containing a difunctional epoxycyclohexane ring ˙Alicyclic epoxy compound 2: Shin-Etsu Chemical Co., Ltd., trade name "KR-470", containing a tetrafunctional epoxy cyclohexane ring ˙Alicyclic epoxy compound 3: manufactured by ENEOS Co., Ltd., trade name "EPOCHALIC (registered trademark) THI-DE", containing a monofunctional epoxycyclohexane ring and a monofunctional cyclopentane ring ˙Alicyclic epoxy compound 4: manufactured by DAICEL, trade name "EPOLIDE (registered trademark) GT401", containing a tetrafunctional epoxycyclohexane ring ˙Rubber-modified epoxy resin mixture 1: Contains rubber-modified epoxy resin obtained by modifying bisphenol A-type epoxy resin with nitrile rubber, manufactured by ADEKA, trade name "ADEKARESIN (registered trademark) EPR- 4030” (Nitrile Rubber Modified Epoxy Resin 40% by mass, Bisphenol A Type Epoxy Resin 60% by mass) ˙Rubber-modified epoxy resin mixture 2: Contains rubber-modified epoxy resin obtained by modifying bisphenol A type epoxy resin with nitrile rubber, manufactured by DIC Co., Ltd., trade name "EPICLON (registered trademark) TSR- 960” (30% by mass of nitrile rubber modified epoxy resin, 70% by mass of bisphenol A type epoxy resin) ˙Oxetane compound: Toagosei Co., Ltd., trade name "ARONEOXETANE (registered trademark) OXT-121" ˙Epoxy compound: manufactured by Mitsubishi Chemical Co., Ltd., trade name "jER (registered trademark) 827" ˙Cation initiator 1: manufactured by Sanshin Chemical Co., Ltd., trade name "SANAID (registered trademark) SI-100" ˙Cation initiator 2: Sanshin Chemical Industry Co., Ltd., trade name "SANAID (registered trademark) SI-110" ˙Cation initiator 3: manufactured by Sanshin Chemical Co., Ltd., trade name "SANAID (registered trademark) SI-B3" ˙Cation initiator 4: manufactured by King Industries, inc., trade name "K-PURE (registered trademark) TAG-2678" ˙Comparative hardener: 2-methyl-4-methylimidazole ˙Conductive particles: silver particles, small flakes, average particle size 6.7μm ˙Solvent 1: γ-butyrolactone ˙Solvent 2: propylene carbonate

(1) Conductivity A conductive resin composition (length 60mm, width 1mm, thickness about 100μm, 5 rows per substrate) was printed on a 100mm x 65mm glass epoxy substrate using a metal plate. Next, heat the conductive resin composition for a predetermined curing time at the predetermined curing temperature described in Tables 1 to 5 using a hot air drying oven to prepare a measurement sample. For this measurement sample, the resistance value (R, Ω) at both ends was measured using a resistance measuring device of the four-terminal method. Next, the thickness of the cured product of the conductive resin composition was measured using a micrometer. From the resistance value (R, Ω), cross-sectional area (S, cm ² ) and length (L, cm) of the cured product of the conductive resin composition, the specific resistance (Ω･cm) is calculated using the following formula (1). In addition, 5 lines of printing were performed on one glass epoxy board|substrate, the specific resistance was measured, and the average value was calculated|required. When the value of the specific resistance is 5.00E-04Ω·cm or less, it is evaluated that the conductivity is excellent.

[mathematical formula 1]

(2) Bonding strength On the copper foil surface of a 70mm square glass epoxy copper-clad laminate, coat the conductive resin composition listed in Tables 1-5. Next, silicon crystal grains of 2 mm square were mounted on the above-mentioned coated portion. Then, heat the conductive resin composition for a predetermined curing time at the predetermined curing temperature described in Tables 1 to 5 using a hot air drying oven to prepare a sample for measuring adhesion strength. The thickness of the bonding layer is 20μm~40μm after hardening. The above-mentioned adhesive strength measurement sample was fixed to an adhesive strength tester Bondtester 4000 Plus (manufactured by Nordson Dage) equipped with a cartridge Cartridge S200KG (manufactured by Nordson Dage). After adjusting one side of the silicon grain to be parallel to the surface of the device tool, take the copper foil surface of the glass epoxy copper-clad laminate as a reference, and measure the bonding strength under the conditions of a height of 0.1mm and a moving speed of 0.3mm/s. It measured 5 times about each Example and the comparative example, and calculated|required the average value. When the value of the adhesive strength was 2.0 kgf or more, it was evaluated that the adhesive strength was excellent.

(3) Solvent resistance (acetone friction test) An acetone friction test was performed using the measurement sample used for electrical conductivity evaluation. Specifically, the hardened part of the conductive resin composition was wiped back and forth five times or more with a white cloth soaked in acetone, and the coloring on the cloth was confirmed. When there is no coloring, the solvent resistance is excellent, and the evaluation is "○"; when there is slight coloring, the solvent resistance is slightly better, and the evaluation is "△"; when there is coloring, the solvent resistance is poor, and the evaluation is "X". Furthermore, all Examples and Comparative Examples contain silver particles, and when the resin part of the cured product is dissolved in acetone, the cloth after wiping will be stained gray. If it is "△" or "〇", it is evaluated as practical.

[Table 1]

[Table 2]

[table 3]

[Table 4]

[table 5]

The results are shown in Tables 1 to 5. According to the conductive resin composition of each embodiment, the conductivity, adhesive strength, and solvent resistance are all excellent.

Comparative Example 1 is an example not containing the rubber-modified epoxy resin (A-2), and has poor electrical conductivity.

Comparative Example 2 is an example containing a rubber-modified epoxy resin (A-2) exceeding the upper limit, and has poor adhesion strength and solvent resistance.

Comparative Example 2-1 is an example in which the cationic initiator (B) is replaced with an imidazole-based hardener, and the conductivity, adhesive strength and solvent resistance are poor. Comparative Example 2-2 is an example in which the alicyclic epoxy compound (A-1) was replaced by an epoxy compound, and the cationic initiator (B) was replaced by an imidazole-based hardener. The conductivity was poor.

Comparative Example 3-1~Comparative Example 3-3 are examples of changing the content ratio of rubber-modified epoxy resin (A-2) in the formulation system not containing alicyclic epoxy compound (A-1), but even Increasing the content ratio of the rubber-modified epoxy resin (A-2) did not improve the conductivity.

On the other hand, in Examples 1 to 6, since the content ratio of the rubber-modified epoxy resin was increased in the formulation system containing a predetermined amount of alicyclic epoxy compound (A-1), it was confirmed that the conductivity was improved. The effect.

From the comparison between Comparative Example 4-1 and Comparative Example 4-2, under the condition that the content ratio of the alicyclic epoxy compound (A-1) is less than the lower limit, even if the compounded rubber-modified epoxy resin (A-2 ), and no improvement in conductivity was seen.

On the other hand, from the comparison between Example 4-1 and Comparative Example 4-3, when the content ratio of the alicyclic epoxy compound (A-1) is within the specified range, when the rubber-modified epoxy In the case of resin (A-2), it was confirmed that it has the effect of improving electrical conductivity.

1: Multilayer substrate 2: Insulation layer 3: Filler made of hardened conductive resin composition L1~L6: conductive layer

FIG. 1 is a schematic enlarged cross-sectional view showing a multilayer substrate according to an embodiment of the present invention.

(none)

Claims (6)

A conductive resin composition containing at least: a cationic polymerizable compound (A) comprising (A-1) an alicyclic epoxy compound and (A-2) a rubber-modified epoxy resin, (B) a cationic initiator, and (C) conductive particles; And, relative to 100 parts by mass of the aforementioned (A) cationic polymerizable compound, the aforementioned (B) cationic initiator is 0.3 to 5 mass parts, and the aforementioned (C) conductive particle is 250 to 2400 mass parts; The content ratio of the said alicyclic epoxy compound (A-1) in (A) component is 20 mass % or more, The content rate of the said rubber modified epoxy resin (A-2) in (A) component is 0.4-15 mass %. The conductive resin composition according to claim 1, wherein the aforementioned component (A) further contains (A-3) an oxetane compound, and The content rate of the said oxetane compound (A-3) in (A) component is 10-30 mass %. The conductive resin composition according to claim 1, wherein the aforementioned cationic initiator (B) is at least one selected from the group consisting of the following salts: (B-1) a compound consisting of a percite cation and an antimony anion Salts, (B-2) salts composed of percite cations and phosphorus hexafluoride anions, (B-3) salts composed of percite cations and tetrakis (pentafluorophenyl) borate anions, and (B-4) salts composed of The salt of quaternary ammonium and borate anion. The conductive resin composition according to claim 2, wherein the aforementioned cationic initiator (B) is at least one selected from the group consisting of the following salts: (B-1) a compound consisting of a percite cation and an antimony anion Salts, (B-2) salts composed of percite cations and phosphorus hexafluoride anions, (B-3) salts composed of percite cations and tetrakis (pentafluorophenyl) borate anions, and (B-4) salts composed of The salt of quaternary ammonium and borate anion. A cured product of a conductive resin composition is a cured product of the conductive resin composition according to any one of claims 1 to 4. A multi-layer substrate, which is composed of a plurality of conductive layers and an insulating layer between the plurality of conductive layers, and is formed with at least one hole penetrating through the insulating layer, and filling the holes as claimed in items 1 to 4 In any one of the conductive resin compositions, the conductive layers located at both ends of the hole are electrically connected to each other through the cured product of the conductive resin composition.

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