WO2013115360A1

WO2013115360A1 - Conductive adhesive and electronic device using same

Info

Publication number: WO2013115360A1
Application number: PCT/JP2013/052348
Authority: WO
Inventors: 内田　博; 篠崎　研二; 圭孝石橋; 克昭菅沼
Original assignee: 昭和電工株式会社; 国立大学法人大阪大学
Priority date: 2012-02-03
Filing date: 2013-02-01
Publication date: 2013-08-08
Also published as: TW201346006A; TWI582210B; JPWO2013115360A1; JP6080776B2

Abstract

[Problem] To provide: a conductive adhesive which is not susceptible to deterioration in a bonded portion caused by a halogen; and an electronic device which uses the conductive adhesive. [Solution] A conductive adhesive, which contains a conductive filler and a binder resin, and wherein the binder resin contains an epoxy resin in which the sum of the total chlorine concentration and the total bromine concentration is 300 ppm by mass or less relative to the total amount of the epoxy resin contained in the binder resin. This epoxy resin preferably has a sum of the total chlorine concentration and the total bromine concentration of 50 ppm by mass or less, and is preferably obtained by epoxidizing a carbon-carbon double bond of a starting material compound (a base material) that has a carbon-carbon double bond, while using hydrogen peroxide as an oxidant.

Description

Conductive adhesive and electronic device using the same

The present invention relates to a conductive adhesive and an electronic device using the same.

In recent years, conductive adhesives are often used in place of solder for assembling semiconductor elements and various electric / electronic components or bonding them to substrates. Many of such conductive adhesives usually contain an epoxy resin and conductive metal particles.

Patent Document 1 listed below discloses a metal filler containing copper as a conductive adhesive having sufficient strength and conductivity, an epoxy compound, a novolac-type phenol resin, and a low-molecular polyhydric phenol compound. And a conductive adhesive containing a curing agent as essential components is described. Patent Document 2 below describes a conductive adhesive containing an epoxy resin and a phenol resin that are liquid at room temperature as a conductive adhesive having better adhesive strength.

Japanese Unexamined Patent Publication No. 2000-192000 JP 2009-7453 A

However, the above conventional technique has a problem that the reliability of the conductive adhesive cannot be ensured due to significant migration or the like caused by halogen such as chlorine contained in the epoxy compound (resin) to be used.

An object of the present invention is to provide a conductive adhesive that hardly causes deterioration of a bonded portion due to halogen and an electronic device using the conductive adhesive.

In order to achieve the above object, according to an embodiment of the present invention, in a conductive adhesive including a conductive filler and a binder resin, the binder resin includes an epoxy resin, and the total chlorine concentration and the total bromine concentration with respect to the total amount of the epoxy resin. The total is 300 ppm by mass or less.

Further, the total chlorine concentration and the total bromine concentration with respect to the total amount of the epoxy resin is 50 mass ppm or less.

Further, the epoxy resin is obtained by epoxidizing a carbon-carbon double bond of a raw material compound (substrate) having a carbon-carbon double bond with a peroxide as an oxidizing agent. Further, the raw material compound (substrate) is a compound having two or more allyl ether groups.

The content of the binder resin in the conductive adhesive is 5 to 99% by volume.

The conductive filler is at least one metal selected from the group consisting of gold, silver, copper, nickel, aluminum, palladium, or particles or fibers made of an alloy of the plurality of metals, gold, palladium on the metal surface , Metal particles or fibers plated with any of silver, resin core balls plated with any of nickel, gold, palladium, and silver on resin balls, or particles or fibers of carbon or graphite.

One embodiment of the present invention is an electronic device, which joins a semiconductor element, a solar panel, a thermoelectric element, a chip component, a discrete component, or a combination thereof to any of the substrates by any one of the conductive adhesives described above. It is implemented. In addition, the electronic device is characterized in that the wiring of the film antenna, the keyboard membrane, the touch panel, and the RFID antenna is formed and connected to the substrate by any one of the above-described conductive adhesives.

According to the present invention, it is possible to suppress degradation of the bonded portion derived from halogen during assembly of a semiconductor element and various electric / electronic components or bonding to a substrate.

Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described.

The conductive adhesive according to this embodiment includes a resin that functions as a conductive filler and a binder, the resin includes an epoxy resin, and the total of the total chlorine concentration and the total bromine concentration with respect to the total amount of the epoxy resin is 300 mass ppm or less. It is characterized by being.

The total of the total chlorine concentration and the total bromine concentration with respect to the total amount of the epoxy resin is preferably 50 mass ppm or less, and more preferably 10 mass ppm or less.

Here, the epoxy resin can be obtained, for example, by epoxidizing a carbon-carbon double bond of a raw material compound (substrate) having a carbon-carbon double bond using peroxide as an oxidizing agent. According to this method, unlike the conventional epoxy resin production method using epihalohydrin, a compound having a carbon-chlorine bond is not used as a raw material. Therefore, the epoxy resin as the binder resin constituting the conductive adhesive according to the embodiment of the present invention is And substantially free of compounds containing carbon-chlorine bonds in the molecule. In the present specification, “substantially free” means that a compound containing a carbon-chlorine bond is not used as a raw material used for synthesizing an epoxy resin, that is, such a compound in an epoxy resin and a reaction product thereof. It means that the content of is zero. Examples of the oxidizing agent include hydrogen peroxide and peracetic acid, but hydrogen peroxide that is inexpensive and easy to handle is more preferable. In particular, it is preferable to use a 10 to 60% by mass aqueous solution of hydrogen peroxide in terms of reactivity and handling. In this method, since the raw material does not contain chlorine and bromine, an epoxy resin having a low chlorine and bromine content can be obtained. In this specification, “epoxy resin” refers to a binder component of a conductive adhesive, that is, a compound having an oxirane ring constituting a cured product, and includes any of a monomer, an oligomer, and a polymer.

Examples of the raw material compound (substrate) having a carbon-carbon double bond include a cycloalkene having 4 to 12 carbon atoms, an unconjugated cycloalkadiene, cycloalkatriene, or cycloalkatetraene having 6 to 12 carbon atoms, or And compounds having an allyl ether group. The allyl ether _groups, refers to a functional group represented by _{CH 2 = CH-CH 2 -0-} .

Examples of such raw material compounds (substrates) include phenyl allyl ethers, cresol monoallyl ethers, cyclohexenes, cyclooctenes, and the like, for example, bisphenol-A diallyl ether, allyl ether compounds of novolac phenolic resins, cyclohexane Dimethanol diallyl ether, trimethylolpropane triallyl ether, pentaerythritol tetraallyl ether, 3,4-epoxycyclohexane-1-carboxylic acid allyl ester, 3,4-cyclohexenylmethyl-3 ′, 4′-cyclohexene carboxylate, etc. Can be illustrated.

Among these, it is preferable to use a compound having two or more allyl ether groups. For example, a glycidyl ether compound obtained by epoxidizing a compound represented by the following general formula (1) with an oxidizing agent such as hydrogen peroxide is used. is there.

{Wherein R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 4 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, or R ¹ And R ² together form a cycloalkane having 3 to 12 carbon atoms, and R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, carbon A cycloalkyl group having 4 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms, and n represents an integer of 0 or 1. }

Specific examples of such compounds include bisphenol-A diallyl ether, bisphenol-F diallyl ether, 2,6,2 ', 6'-tetramethylbisphenol-A diallyl ether, 2,2'-diallyl bisphenol- A diallyl ether, 2,2'-di-t-butylbisphenol-A diallyl ether, 3,3 ', 5,5'-tetramethylbiphenyl-4,4'-diallyl ether, 2,2'-diisopropylbiphenol diallyl Ether, 4,4′-ethylidene bisphenol diallyl ether, 4,4′-cyclohexylidene bisphenol diallyl ether, 4,4 ′-(1-α-methylbenzylidene) bisphenol diallyl ether, 4,4 ′-(3,3 , 5-Trimethylcyclohexylidene) bisphe Over Luzia Lil ether, 4,4 '- (1-methyl - benzylidene) bisphenol diallyl ether.

Specific examples of the biphenyl diallyl ether having an aromatic ring and two allyl ether groups include 2,2'-biphenyl diallyl ether and tetramethylbiphenyl diallyl ether.

Also, compounds obtained by allyl etherification of polyphenols such as cresol novolac resins and phenol novolac resins can be used.

Aliphatic polyallyl ethers having two or more allyl ether groups can also be used. Specifically, 1,5-pentanediol diallyl ether, 1,6-hexanediol diallyl ether, 1,9- Nonanediol diallyl ether, 1,10-decanediol diallyl ether, neopentyl glycol diallyl ether, glycerin triallyl ether, trimethylolpropane triallyl ether, pentaerythritol tetraallyl ether and the like can be mentioned.

Specific examples of the alicyclic diolefin having two allyl ether groups include 1,4-cyclohexanedimethanol diallyl ether and tricyclo [5.2.1.0 ^2,6 ] decandimethanol diallyl ether. Can be mentioned.

In addition, the resin functioning as a binder may include other thermoplastic resins and thermosetting resins in addition to the epoxy resin. Examples of the thermoplastic resin include acrylic resin, ethyl cellulose, polyester, polysulfone, phenoxy resin, and polyimide. Examples of thermosetting resins include amino resins such as urea resins, melamine resins, and guanamine resins; oxetane resins; phenol resins such as resol types and novolac types; and silicone-modified organic resins such as silicone epoxies and silicone polyesters. Is done. These other thermoplastic resins and thermosetting resins, which function as a binder, preferably have a low chlorine concentration and bromine concentration, and are the sum of the total chlorine concentration and the total bromine concentration relative to the total amount of the resin functioning as the binder. Is preferably 300 ppm by mass or less. More preferably, it is 50 mass ppm or less, More preferably, it is 10 mass ppm or less.

As epoxy resins, bisphenol A type and bisphenol F type epoxy resins are used because excellent adhesiveness and excellent heat resistance can be obtained even if the blending amount of the resin is suppressed to an amount that does not impair the conductivity. preferable. Further, from the same viewpoint, a resol type phenol resin may be mixed.

When a resin that is liquid at room temperature is used as the resin, the vehicle can be obtained without using an organic solvent, and the drying step can be omitted. For this reason, it is preferable to use a liquid epoxy resin.

Liquid epoxy resins include bisphenol A type epoxy resins having an average molecular weight of about 400 or less; branched polyfunctional bisphenol A type epoxy resins such as p-glycidoxyphenyldimethyltolylbisphenol A diglycidyl ether; bisphenol F type Epoxy resin; phenol novolac type epoxy resin having an average molecular weight of about 570 or less; 1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1, 10-decanediol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether Aliphatic polyglycidyl ethers such as vinyl (3,4-cyclohexene) dioxide, 3,4-epoxycyclohexylcarboxylic acid (3,4-epoxycyclohexyl) methyl, bis (3,4-epoxy-6-methylcyclohexyl) adipate Examples thereof include alicyclic epoxy resins comprising at least one of methyl), 2- (3,4-epoxycyclohexyl) 5,1-spiro (3,4-epoxycyclohexyl) -m-dioxane as a constituent component.

In addition, the liquid epoxy resin is compatible within the range in which the mixed system exhibits fluidity, and within a range in which the total chlorine concentration and total bromine concentration with respect to the total amount of the epoxy resin is 300 ppm by mass or less. A resin having a solid or ultra-high viscosity may be mixed and used. Examples of such resins include high molecular weight bisphenol A type epoxy resins, diglycidyl biphenyl, novolac epoxy resins, and epoxy resins such as tetrabromobisphenol A type epoxy resins; novolak phenol resins and the like.

As a curing mechanism of the epoxy resin, a self-curing resin may be used, or a curing agent or a curing accelerator may be used.

Examples of curing agents usually used for the epoxy resin include acid anhydrides, polyamines, polyphenol compounds, and the like.

As such a curing agent, specifically in the case of an acid anhydride, hexahydrophthalic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, 3-methyl-1,2,3,6-tetrahydrophthalic anhydride, 4-methyl-1,2,3,6-tetrahydrophthalic anhydride, 3-methyl-hexahydrophthalic anhydride, 4-methyl-hexahydrophthalic anhydride Acid, 5-norbornene-2,3-dicarboxylic acid anhydride, norbornane-2,3-dicarboxylic acid anhydride, methyl-3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride, methyl- In addition to 3,6-endomethylenehexahydrophthalic anhydride, dodecenyl succinic anhydride and alicyclic compounds having conjugated double bonds such as α-terpinene and alloocimene Alicyclic carboxylic anhydride-based curing agents such as Diels-Alder reaction products with maleic acid and hydrogenated products thereof, and aromatic anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride Benzophenone tetracarboxylic acid anhydride, polyadipic acid anhydride, polyazeline acid anhydride, polysebacic acid anhydride, and the like.

Polyamines include aliphatic amines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenediamine, diethylaminopropylamine, N-aminoethylpiperazine, isophoronediamine, m-xylylenediamine, p-xylylenediamine, hydrogenated Examples of the aromatic amine include m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

As the polyphenol compound, a so-called phenol resin such as a phenol novolak resin or a cresol novolak resin, polyvinyl phenol, or the like is used.

Also, in order to accelerate the reaction between the epoxy resin and the curing agent, a curing accelerator such as imidazole or dicyandiamide can be used in combination. Needless to say, it is preferable that the content of chlorine and bromine is low in these curing agents and curing accelerators.

In addition, the conductive filler used in the conductive adhesive of this embodiment is made of at least one metal selected from the group consisting of gold, silver, copper, nickel, aluminum, and palladium, or an alloy of the plurality of metals. Particles or fibers, metal particles or fibers plated with gold, palladium or silver on the metal surface, resin core balls plated with nickel, gold, palladium or silver on resin balls, carbon or graphite It is preferably a particle or fiber, but is not limited thereto, and may be used as long as it can exhibit electrical conductivity and does not significantly deteriorate the adhesiveness (to the extent that it cannot be used as an adhesive). it can. The shape of the conductive filler is not particularly limited, and in the case of particles, various shapes such as a spherical shape, a flat plate shape (flat shape), and a rod shape can be used. A preferable particle diameter is 5 nm to 20 μm. The particle diameter here is a number-based D50 (median diameter) particle measured by a laser diffraction / scattering method when the particle diameter is 500 nm or more, and by a dynamic light scattering method when it is less than 500 nm. Means diameter. In the case of fibers, those having a diameter of 0.1 to 3 μm, a length of 1 to 10 μm, and an aspect ratio of 5 to 100 are preferable.

The compounding amount of the resin in the conductive adhesive is preferably 5 to 99% by volume with respect to the total of the resin and the conductive filler, from the printability and the conductivity of the conductive layer obtained by curing. When the metal particles are uniformly dispersed in the binder resin, the content is more preferably 40 to 85% by volume, and still more preferably 60 to 75% by volume. In order to construct an anisotropic conductive adhesive that enables anisotropic conductive connection, the binder resin content is preferably 95 to 99% by volume. Here, the anisotropic conductive connection refers to a connection that is conductive between opposing electrodes (vertical direction) and insulative between adjacent electrodes (horizontal direction). An anisotropic conductive adhesive is used by being sandwiched between electrodes electrically connected by anisotropic conductive connection.

The conductive adhesive of the present embodiment is selected from the type and amount of the binder resin including the conductive filler and the epoxy resin, and if necessary, by using a diluent, a printing method or application to an element, a substrate, etc. Depending on the method, it can be adjusted to an appropriate viscosity. For example, in the case of screen printing, an organic solvent having a boiling point of 200 ° C. or higher is preferably used as a diluent. Examples of such an organic solvent include diethylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, and diethylene glycol monobutyl ether. Can be mentioned. Although it depends on the printing method or the coating method, the preferred viscosity of the conductive adhesive is 20 Pa · s to 500 Pa · s as measured at 25 ° C. with a rheometer.

In addition to the above, the conductive adhesive of the present embodiment includes an aluminum chelate compound such as diisopropoxy (ethylacetoacetate) aluminum as a dispersion aid, if necessary, such as isopropyltriisostearoyl titanate. An aliphatic polycarboxylic acid ester; an unsaturated fatty acid amine salt; a surfactant such as sorbitan monooleate; or a polymer compound such as a polyesteramine salt or polyamide may be used. Moreover, you may mix | blend an inorganic and organic pigment, a silane coupling agent, a leveling agent, a thixotropic agent, an antifoamer, etc.

The conductive adhesive of the present embodiment can be prepared by uniformly mixing the blended components by a mixing means such as a reika machine, a propeller stirrer, a kneader, a roll, and a pot mill. Preparation temperature is not specifically limited, For example, it can prepare at normal temperature.

The conductive adhesive of the present embodiment can be printed or applied to the substrate by any method such as screen printing, gravure printing, dispensing, or the like. When an organic solvent is used as a diluent, the organic solvent is volatilized after printing or coating at room temperature or by heating. Next, the resin is usually heated at 70 to 250 ° C., for example, in the case of an epoxy resin using a phenol resin as a curing agent, for 2 to 30 minutes depending on the type of the resin and the curing agent or curing accelerator. By curing, a conductive pattern can be formed on a necessary portion of the substrate surface.

Thus, using the conductive adhesive of this embodiment, an electronic device in which a semiconductor element, a solar panel, a thermoelectric element, a chip part, a discrete part, or a combination thereof is mounted on a substrate can be formed. In addition, by using the conductive adhesive of the present embodiment, it is also possible to form an electronic device in which a film antenna, a keyboard membrane, a touch panel, and an RFID antenna are formed and connected to a substrate.

Examples of the present invention will be specifically described below. In addition, the following examples are for facilitating understanding of the present invention, and the present invention is not limited to these examples.
The conductive filler used in the examples is the following two types of silver particles.
N300: Toxen Industries Co., Ltd. silver particle (flat plate) D50 = 470 nm
EHD: Silver particles (spherical) manufactured by Mitsui Mining & Smelting Co., Ltd. D50 = 620 nm
Here, D50 is a number-based median diameter measured by N300 using a dynamic light scattering method and EHD using a laser diffraction / scattering method. In addition, N300 had a number average value of 30 nm obtained by observing 10 points by SEM while changing the observation location at a magnification of 30,000 times.

Synthesis example 1
- 3,4 Preparation of epoxy-cyclohexane-1-carboxylic acid allyl ester and its polymer _{_{_{Na 2 WO 4 · 2H 2 O}}} (500mg, 1.5mmol), 40 wt% aqueous hydrogen peroxide (7.65 g, 90 mmol), methyl trioctylammonium hydrogen sulfate (260 mg, 0.56 mmol) and allyl 3-cyclohexene-1-carboxylate (12.5 g, 75 mmol) were mixed and reacted at 25 ° C. for 15 minutes, and then 70 ° C. The mixture was heated up to 3.5 hours and stirred for 3.5 hours. After completion of the reaction, it was cooled to room temperature. After post-treatment with a saturated aqueous solution of sodium thiosulfate, the organic layer was taken out. When the obtained solution was measured by gas chromatography, the conversion of allyl 3-cyclohexene-1-carboxylate as a raw material was 79% and 3,4-epoxycyclohexane-1 as a bifunctional epoxy monomer was obtained. -It was confirmed that allyl carboxylic acid ester was produced in a yield of 69%. The result was that no diepoxide was produced and the selectivity of monoepoxide was 87.3%.

In addition, the conversion rate and the selectivity were calculated by the following calculation formula based on the result analyzed by gas chromatography.

Conversion rate (%) = (1−number of moles of raw material remaining / number of moles of raw material used) × 100
Selectivity (%) = {(yield (%) / conversion (%)} × 100

100 g of 3,4-epoxycyclohexane-1-carboxylic acid allyl ester obtained by scaling up in substantially the same manner as above, 80 g of diethylene glycol monomethyl ether acetate, 89 g of benzoic acid allyl ester, t-butylisopropyl peroxycarbonate (Nippon Yushi Co., Ltd., Perbutyl I (containing 75% of the main component)) was charged into a 500 ml separable flask equipped with 4.7 g and a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen inlet tube, and heated to 110 ° C. Thereafter, the mixture was stirred for 1 hour. t-Butyl isopropyl peroxycarbonate was added in 4.7 g portions every 3 hours, and after completion of addition, the mixture was further aged in a nitrogen atmosphere at 110 ° C. for 2 hours to obtain an epoxy group-containing polymer solution. Obtained. The reaction was carried out under a nitrogen stream.

During the reaction, the remaining amount of 3,4-epoxycyclohexane-1-carboxylic acid allyl ester and benzoic acid allyl ester was measured by gas chromatography, and the reaction was followed by calculating the conversion rate. The following points were defined as reaction end points. Together with the results of gel permeation chromatograph (hereinafter abbreviated as GPC) at this point, it was confirmed that the polymerization reaction had progressed. The epoxy equivalent of the solid content of the obtained resin was 381 g / eq. (Theoretical epoxy equivalent 344 g / eq.) And the number average molecular weight Mn was 1,315. Moreover, the total chlorine concentration was 6 mass ppm, and the total bromine concentration was less than 1 mass ppm.

The epoxy equivalent, number average molecular weight, total chlorine concentration and total bromine concentration were determined by the following methods, respectively.

<Epoxy equivalent>
The epoxy equivalent was determined according to JIS-K7236. Weigh 0.1 to 0.2 g of the sample, put it in an Erlenmeyer flask, and add 10 mL of chloroform to dissolve. Next, 20 mL of acetic acid is added, followed by 10 mL of tetraethylammonium bromide solution (100 g of tetraethylammonium bromide dissolved in 400 mL of acetic acid). 4 to 6 drops of crystal violet indicator was added to this solution, and titrated with a 0.1 mol / L perchloric acid acetic acid solution. Based on the titration result, the epoxy equivalent was determined according to the following formula.
Epoxy equivalent (g / eq) = (1000 × m) / {(V1−V0) × c}
m: weight of the sample (g)
V0: Amount of perchloric acid acetic acid solution consumed for titration to the end point in the blank test (mL)
V1: Amount of perchloric acid acetic acid solution consumed for titration to the end point (mL)
c: Concentration of perchloric acid acetic acid solution (0.1 mol / L)

<Number average molecular weight>
Using gel permeation chromatography (hereinafter abbreviated as GPC), the value was calculated as a value converted to polystyrene (using standard sample STANDARD SM-105 manufactured by Showa Denko KK). The measurement conditions for GPC are as follows.
Device name: HPLC unit HSS-2000 manufactured by JASCO Corporation
Column: Shodex column LF-804
Mobile phase: Tetrahydrofuran Flow rate: 1.0 mL / min Detector: manufactured by JASCO Corporation RI-2031Plus
Temperature: 40.0 ° C
Sample amount: 100 μl of sample loop Sample concentration: prepared at around 0.1% by mass.

<Total chlorine concentration and total bromine concentration>
The chlorine concentration and bromine concentration were measured by burning and decomposing the epoxy compound at a high temperature of 800 ° C. or higher, absorbing the decomposed gas in ultrapure water, etc., and quantifying it by ion chromatography (pretreatment combustion apparatus) AGF-100 (manufactured by Mitsubishi Chemical Analytic Co., Ltd.), gas adsorption device GA-100 (manufactured by Mitsubishi Chemical Analytic Co., Ltd.), ion chromatograph ICS-100 (manufactured by Dionex Corporation)).

Synthesis example 2
Synthesis of 3,3 ′, 5,5′-tetramethylbiphenyl-4,4′-glycidyl ether 3,3 ′, 5,5′-tetramethyl-4,4′-biphenyl was added to a 2000 ml eggplant type flask. Diol (China: Gansu Chemical Research Institute) 150g (0.619mol), 50% water content 5% -Pd / C (Pd / C with 5% by mass of Pd with respect to the total mass of Pd and C was impregnated with water. The mass of water is 50% by mass with respect to the total mass of Pd / C and water) -STD type (manufactured by N.E. Chemcat Co., Ltd.) 1.32 g (0.310 mol), triphenylphosphine (Hokuko Chemical Co., Ltd.) 1.624 g (6.19 mmol) manufactured by company), 171 g (1.24 mol) potassium carbonate (manufactured by Nippon Soda Co., Ltd.), 136 g (1.36 mol) allyl acetate (manufactured by Showa Denko KK), And 68.1 g of isopropanol were added and reacted at 85 ° C. for 8 hours in a nitrogen atmosphere. After the reaction, a part was sampled, diluted with ethyl acetate, and analyzed by gas chromatography. The ratio of 3,3 ′, 5,5′-tetramethylbiphenyl-4,4′-diallyl ether to monoallyl ether was 97 : Confirmed to be up to 3.

Thereafter, 200 g of toluene was added to the reaction solution, Pd / C and the precipitated solid were removed by filtration, and isopropanol and toluene were distilled off by an evaporator. After repeating this reaction and the post-treatment operation four times, a distillate 510 g (isolation yield 66%, diallyl ether 97.9%, the rest is monoallyl ether) by molecular distillation apparatus (manufactured by Otsuka Kogyo Co., Ltd.). ), 231.7 g of non-distilled product (97.5% diallyl ether) was obtained. The distillate is a solid having a melting point of 51.7 ° C., and the viscosity at 60 ° C. measured by a rheometer (Phisica MCR301 manufactured by Anton Paar Co., Ltd .: CP25-2, 25 mm diameter, angle 2 °) is 29 mPa · s. Met.

185 g (0.576 mol) of 3,3 ′, 5,5′-tetramethylbiphenyl-4,4′-diallyl ether obtained by the above operation and 3.785 g of sodium tungstate (manufactured by Nippon Inorganic Chemical Co., Ltd.) 0.0115 mol), 4.389 g (0.0115 mol) of methyltrioctylammonium hydrogen sulfate, 1.278 g (0.0115 mol) of phosphoric acid, and 92.5 g of toluene were placed in a 300 ml three-necked flask equipped with a dropping funnel and a Dimroth condenser. The mixture was heated to 70 ° C. with an oil bath while stirring with a magnetic stirrer, and 168 g (1.728 mol) of 35% aqueous hydrogen peroxide solution was added dropwise so that the reaction temperature did not exceed 75 ° C. After completion of dropping, stirring was continued for 2 hours, and the reaction solution was cooled to room temperature. Thereafter, 40 g of toluene was added, and the organic layer was separated so that the upper layer was an organic layer and the lower layer was an aqueous layer.

As a result of analyzing this organic layer, the conversion of 3,3 ′, 5,5′-tetramethylbiphenyl-4,4′-diallyl ether was 94.2%, and the selectivity to monoepoxy was 34.9. %, Selectivity to diepoxy was 62.5%. The obtained product was recrystallized twice with toluene to obtain 71.2 g of an epoxidized product (purity is 93.4%). Further, the total chlorine concentration of this epoxidized product measured in the same manner as in Synthesis Example 1 was 5 ppm by mass, the total bromine concentration was less than 1 ppm by mass, and the epoxy equivalent was 189 g / eq. Met.

Synthesis example 3
Synthesis of bisphenol-A-glycidyl ether In a 2000 ml eggplant-shaped flask, 148.4 g (0.650 mol) of bisphenol-A (manufactured by Mitsui Chemicals), 50% water content 5% -Pd / C-STD type (N. 1.38 g (0.650 mmol) manufactured by Echemcat Co., Ltd., 1.639 g (6.50 mmol) triphenylphosphine (produced by Hokuko Chemical Co., Ltd.), 189 g (1.37 mol) potassium carbonate (produced by Nippon Soda Co., Ltd.), 143 g (1.43 mol) of allyl acetate (manufactured by Showa Denko KK) and 64.1 g of isopropanol were added and reacted at 85 ° C. for 8 hours in a nitrogen atmosphere. After the reaction, a part was sampled, diluted with ethyl acetate, and analyzed by gas chromatography, and it was confirmed that the ratio of bisphenol-A-diallyl ether to monoallyl ether was up to 98: 2.

Thereafter, 200 g of toluene was added to the reaction solution, Pd / C and the precipitated solid were removed by filtration, and isopropanol and toluene were distilled off by an evaporator. This reaction and post-treatment operation were repeated four times, and then 493 g of a distillate (isolation yield 61.7%, diallyl ether 98.1%, the rest was mono) by using a molecular distillation apparatus (manufactured by Otsuka Industry Co., Ltd.) Allyl ether), 245 g of non-distilled product (96.5% diallyl ether).

Bisphenol-A-diallyl ether (50.05 g, 162.3 mmol), acetonitrile (26.63 g, 648.7 mmol), ethanol (265.1 g, 5754.2 mmol) obtained by the above operation were placed in a 1 L 4-diameter eggplant type flask. Weighed (acetonitrile concentration 9.9 mol%, pH = 8.2). Saturated aqueous potassium hydroxide solution (KOH / H ₂ O = 110 mg / 100 mL) was added so that the pH was not lower than 9. 45% hydrogen peroxide (53.92 g, 713.5 mmol) was added to the 100 mL dropping funnel over 2 hours. (Acetonitrile concentration 8.1 mol%, pH = 9.2). Saturated aqueous potassium hydroxide solution was added dropwise so that the reaction temperature did not exceed 30 ° C., and the pH was allowed to reach 10.5 over 2 hours (2 hours after the end of the hydrogen peroxide solution addition), and the pH was controlled to 10.5. The mixture was further stirred for 2 hours (reducing the acetonitrile concentration to 6.3 mol%). Acetonitrile (13.31 g, 324.2 mmol) was weighed into a 50 mL dropping funnel and dropped over 2 hours (after addition, acetonitrile concentration was 6.1 mol%). At the same time, 45% aqueous hydrogen peroxide (53.92 g, 713.5 mmol) was added dropwise over 4 hours using a 100 mL dropping funnel (the pH was adjusted to 10 to 10 hours so that the reaction temperature did not exceed 30 ° C. for 4 hours during this period). Then, the mixture was stirred for 4 hours while controlling the pH to 10.5 (acetonitrile concentration at the end of the reaction was 3.5 mol%). The reaction solution was diluted with pure water (100 g), and the solvent was distilled off under reduced pressure. The residue was extracted with ethyl acetate (100 g), pure water (100 g) was added again, and a liquid separation operation was performed. When the obtained solution was measured by gas chromatography, the conversion of the raw material bisphenol A type diallyl ether was 100%, the diepoxy monomer bisphenol A type diglycidyl ether was 87.7%, and monoglycidyl. It was confirmed that the ether was 5.1%.

Ethyl acetate was distilled off with an evaporator to obtain the desired epoxidation product. The chlorine concentration measured in the same manner as in Synthesis Example 1 was 6 ppm by mass, the total bromine concentration was less than 1 ppm by mass, and the epoxy equivalent was 178 g / eq. there were.

Examples 1 to 5, Comparative Example 1
Using the three rolls, the conductive filler and the epoxy resin (Examples 1 to 5) prepared in the synthesis example or jER828 (manufactured by Mitsubishi Chemical Co., Ltd.) (Comparative Example 1) in the proportions shown in Table 1 were added to the resol type alkylphenol resin. (Made by Showa Denko KK: average molecular weight 3400) was mixed and mixed until uniform, then 2-ethyl-4-methylimidazole (manufactured by Shikoku Kasei Co., Ltd.) was added and mixed. The mixture was taken out and diethylene glycol monobutyl ether was stirred and the apparent viscosity of the system at 25 ° C. measured with a rheometer (Phisica MCR301 jig manufactured by Anton Paar: CP25-2 25 mm diameter, angle 2 °) was 150 Pa · s. Finally, mixing and defoaming were carried out using a rotating / revolving mixer Awatori Nertaro ARE-310 (manufactured by Sinky Co., Ltd.) to prepare a conductive adhesive. In any case, the total amount of the conductive filler is 85 parts by mass, and the amount of the resin is 15 parts by mass. The volume content of the resin was calculated based on the specific gravity of the conductive filler and the cured resin.

(1) Production of circuit sample A copper-clad glass epoxy substrate on which a wiring pattern for connecting the conductive adhesive obtained as described above to a resistor electrode was processed using a metal mask having a thickness of 75 μm. Stencil printing was performed at positions corresponding to the electrodes at both ends of the resistor on the copper surface (the pattern shape was such that the electrodes at both ends of the resistor and the copper wiring could be connected). This is tin-plated (thickness: 2 μm) to 2012 size (specific shapes are L, W, d, t (unit: mm) = 5.0 ± 0.2, 2.5 ± 0.2, 0. 5 ± 0.2, 0.5 ± 0.2) chip resistor is crimped by hand and heated at 150 ° C. for 30 minutes to cure the adhesive to connect the chip resistor to the circuit board Thus, a circuit sample was produced.

(2) Measurement of connection resistance The connection resistance (mΩ) of the circuit sample is measured by a tester (manufactured by SANWA, model: PC500a
RS-232C).

(3) Measurement of adhesive strength From the side, push the adhesive part of the circuit sample with a push-pull gauge (manufactured by Maruhishi Kagaku Kikai Seisakusho Co., Ltd., PGD II type) until it peels off the L side of the chip resistor at room temperature By reading the numerical value, the force (N) required for peeling was measured and used as the adhesive strength (initial value).

(4) Migration test The conductive adhesive prepared as described above was screen-printed on a ceramic substrate, cured by heating at 150 ° C. for 30 minutes, a distance of 2 mm between electrodes, a width of 2 mm, a length of 2 cm, A counter electrode having a thickness of 20 μm was produced. A voltage of 10 V was applied between the electrodes, one drop of ion-exchanged water and one electrode were dropped between the electrodes, and a time (min) in which a current flowed 100 mA was defined as a migration time.

The above results are summarized in Table 1.

As shown in Table 1, the connection resistance was almost the same value in the example and the comparative example, and the connection strength was a little lower in the example 1, but the other examples were almost the same value as the comparative example. .
On the other hand, the migration time was more than 10 minutes in all the examples, compared with 0.1 minutes in the comparative example. As a result, it can be seen that the conductive adhesive of the present embodiment has greatly improved migration resistance (characteristic for suppressing migration), and the deterioration of the bonded portion derived from halogen is suppressed.

Claims

A conductive adhesive comprising a conductive filler and a binder resin, wherein the binder resin contains an epoxy resin, and the total chlorine concentration and total bromine concentration with respect to the total amount of the epoxy resin is 300 ppm by mass or less. adhesive.
The conductive adhesive according to claim 1, wherein the total chlorine concentration and total bromine concentration with respect to the total amount of the epoxy resin is 50 ppm by mass or less.
2. The epoxy resin obtained by epoxidizing a carbon-carbon double bond of a raw material compound (substrate) having a carbon-carbon double bond with a peroxide as an oxidizing agent. Or the conductive adhesive of Claim 2.
The conductive adhesive according to any one of claims 1 to 3, wherein the raw material compound (substrate) is a compound having two or more allyl ether groups.
The conductive adhesive according to any one of claims 1 to 4, wherein the content of the binder resin in the conductive adhesive is 5 to 99% by volume.
The conductive filler is at least one metal selected from the group consisting of gold, silver, copper, nickel, aluminum and palladium, or particles or fibers made of an alloy of the plurality of metals, gold, palladium, silver on the metal surface 2. A metal particle or fiber plated with any of the above, a resin core ball plated with any of nickel, gold, palladium, and silver on a resin ball, or particles or fibers of carbon or graphite. The conductive adhesive according to any one of claims 5 to 6.
The conductive adhesive according to any one of claims 1 to 6, wherein a semiconductor element, a solar panel, a thermoelectric element, a chip part, a discrete part, or a combination thereof is mounted on a substrate. Electronic equipment.
An electronic apparatus comprising: a film antenna, a keyboard membrane, a touch panel, an RFID antenna formed with wiring, and connected to a substrate using the conductive adhesive according to any one of claims 1 to 6.