KR20030007741A - Conductive resin composition - Google Patents

Abstract

The present invention discloses a polythiol-based epoxy resin composition having conductivity improved potlife and storage stability compared to a conventional polythiol-based epoxy resin composition.

The present invention provides an epoxy resin (1) having two or more epoxy groups in a molecule, a polythiol compound (2) having two or more thiol groups in a molecule, a solid dispersion latent curing accelerator (3), and a boric acid ester compound (4) And a conductive resin composition containing the conductive particles 5 as essential components, and are suitable for conductive materials in a wide range of fields including the electronics field where low temperature fast curing properties are required.

Description

Conductive resin composition

Since the epoxy resin composition which mix | blended polythiol as a hardening | curing agent and tertiary amine as a hardening accelerator shows fast curing property even at low temperature of 0 degreeC--20 degreeC, it is used especially as an adhesive, sealing agent, mold, etc. which are important for copper type. have.

However, such an epoxy resin composition has a drawback that its pot life is very short from several seconds to several hours after mixing the conventional compounding components and that sufficient time cannot be taken for mixing, defoaming, coating, and the like. In addition, since the worker needs to manufacture the composition at each time, the workability is poor, and the composition remaining without use cannot be preserved, so the hardened product must be disposed of, and it is desirable in terms of saving resources and environmental problems. Not.

JP-A-06-211969 and JP-A 06-211970 disclose solid dispersion type amine adduct-based latent curing accelerators, or compounds having an isocyanate group and at least one primary or secondary amino group in the molecule. An example of a polythiol-based epoxy resin composition formed by blending a reactant of a compound having a curing agent as a curing accelerator has been described. As a result, the usable time has been improved. However, the storage stability of the compound is not sufficient yet. The low temperature fast-curing property which is a characteristic of an epoxy resin composition is not enough to utilize.

Japanese Patent Application Laid-Open No. 10-298526 proposes a circuit connection composition composed of an epoxy resin, a polythiol, a latent curing agent, and conductive particles, but cannot be satisfied in terms of storage stability. .

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polythiol-based one-component epoxy resin composition having conductivity, good low temperature fast curing property, good storage stability, excellent heat resistance and moisture resistance, and is widely used in the field of electronic materials as a composition for circuit connection.

An object of the present invention is to provide a polythiol-based one-component epoxy composition having good storage stability and having conductivity.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the polythiol compound (2) which has two or more thiol groups in a molecule | numerator as a hardening | curing agent in an epoxy resin (1), and solid dispersion type latent hardening accelerator (3) as a hardening accelerator (3) ), The boric acid ester compound (4) and the conductive particles (5) was found to obtain a one-component polythiol-based epoxy resin composition excellent in conductivity, heat resistance, moisture resistance, and storage stability, and completed the present invention.

That is, this invention is an epoxy resin (1) which has two or more epoxy groups in a molecule | numerator, the thiol compound (2) which has two or more thiol groups in a molecule | numerator, a solid dispersion type latent hardening accelerator (3), and a boric acid ester compound (4) And an epoxy resin composition having conductive particles 5 as essential components.

The epoxy resin used for this invention should just have two or more epoxy groups per molecule on average. For example, Polyglycidyl ether obtained by making epichlorohydrin react with polyhydric phenols, such as polyhydric phenols, such as bisphenol A, bisphenol F, bisphenol AD, catechol, and resorcinol, glycerin, and polyethylene glycol; glycidyl ether esters obtained by reacting epichlorohydrin with hydroxycarboxylic acids such as p-hydroxybenzoic acid and β-hydroxynaphthoic acid; Polyglycidyl esters obtained by reacting epichlorohydrin with polycarboxylic acids such as phthalic acid and terephthalic acid; Although epoxidized phenol novolak resin, epoxidized cresol novolak resin, epoxidized polyolefin, cyclic aliphatic epoxy resin, other urethane modified epoxy resin, etc. are mentioned, It is not limited to these.

As the polythiol compound used in the present invention, a very low basic impurity content is preferable from the viewpoint of storage stability. For example, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate), ethylene Polyols such as glycoldithioglycolate, trimethylolpropanetris (β-thiopropionate), pentaerythritol tetrakis (β-thiopropionate) and dipentaerythritol poly (β-thiopropionate); The polythiol compound which has two or more thiol groups in a molecule | numerator is mentioned, without using a basic substance for manufacture like the polythiol compound obtained by esterification of mercapto organic acid.

Similarly, alkyl polythiol compounds, such as 1, 4- butanedithiol, 1, 6- hexanedithiol, and 1, 10- decandithiol; Terminal thiol group-containing polyethers; Terminal thiol group-containing polythioether; Polythiol compounds obtained by the reaction of an epoxy compound and hydrogen sulfide; When it is necessary to use a basic substance as a reaction catalyst in its manufacturing process, such as a polythiol compound having a terminal thiol group obtained by the reaction of a polythiol compound and an epoxy compound, dealkaliation is performed, and the alkali metal ion concentration is 50 ppm or less. The polythiol compound which has two or more thiol groups in the molecule refine | purified so that it may be used can be used.

A three-dimensional polymer can be formed by using together the epoxy resin which has an average of two or more epoxy groups per molecule, and the polythiol compound which has two or more thiol groups in a molecule | numerator. The reaction of a thiol group with an epoxy group is theoretically one-to-one, but actually the thiol group is at least slightly cured when tested for curing experiments. It is good to mix | blend so that the mixing ratio of an epoxy resin and a thiol compound may be set to 0.5-1.5 by the epoxy equivalent number ratio of SH equivalent number / epoxy resin of a thiol compound. If the thiol group / epoxy group is less than 0.5, the curing is insufficient, whereas if the thiol group / epoxy group is more than 1.5, an excess of the curing agent not involved in the curing reaction remains, so that the curing is insufficient. Therefore, since the performance of hardened | cured material may not meet this objective outside of the said range, it is not preferable.

The solid dispersion type latent curing accelerator used in the present invention is a compound which is a solid which is insoluble in an epoxy resin at room temperature, solubilized by heating, and functions as an accelerator, and is an imidazole compound or a solid dispersion type amine adduct-based latent curing solid at room temperature. Accelerators include, for example, reaction products of amine compounds and epoxy compounds (amine-epoxy addition products), reaction products of amine compounds and isocyanate compounds or reaction products of amine compounds and urea compounds (urea-type adducts). . Although the compounding quantity of a solid dispersion type | mold latent hardening accelerator differs according to the kind of this and the kind of epoxy resin to be mix | blended, about 1-60 weight part is generally suitable with respect to 100 weight part of epoxy resins.

Representative examples of commercially available as the above-mentioned solid dispersion type amine adduct-based latent curing accelerators are described below, but are not limited thereto. For example, as an amine-epoxy addition system, "Amicure PN-23", "Amicure PN-H", "Amicure MY-24" [brand name, product made by Ajinomoto Co., Ltd.], "Hardner X-3661S" [ Product name, ACC Al Co., Ltd., "Hardner X-3670S" [brand name, ACC Al Co., Ltd.], "Novacure HX-3742", "Novacure HX-3721" [brand name , Asahi Kasei Co., Ltd.], etc., As the urea-type additive system, "Fuji Cure FXE-1000", "Fuji Cure FXR-1030" [brand name, Fuji Kasei Co., Ltd.] etc. are mentioned. have.

The boric acid ester compound which improves the storage stability of the polythiol-based epoxy composition in the present invention and plays an important role in its monolithism is not yet detailed in terms of its mechanism, but is believed to be encapsulated by reaction modification with the surface of the latent curing accelerator. Representative examples of the boric acid ester compound include trimethyl borate, triethyl borate, tri-n-propyl borate, triisopropyl borate, tri-n-butyl borate, tripentyl borate, triaryl borate, trihexyl borate, tricyclohexyl borate, tri Octylborate, trinonylborate, tridecylborate, tridodecylborate, trihexadecylborate, trioctadecylborate, tris (2-ethylhexyloxy) borane, bis (1,4,7,10-tetraoxound (1,4,7,10,13-pentaoxatetradecyl) (1,4,7-trioxoundecyl) borane, tribenzylborate, triphenylborate, tri-o-tolylborate, tri-m -Tolylborate, triethanolamine borate, etc. are mentioned.

As the addition method of these boric acid ester compounds, in addition to mix | blending simultaneously with each component, such as an epoxy resin, a polythiol compound, and a solid dispersion type | mold latent hardening accelerator, it can mix with a solid dispersion type latent hardening accelerator previously. As a mixing method at this time, it can carry out by making both contact in solvent, such as methyl ethyl ketone, toluene, or a solvent-free, or in liquid epoxy resin. 0.1-20 weight part of boric ester compounds are mix | blended with respect to 100 weight part of epoxy resins. If it is less than 0.1 part by weight, the stability of the life is poor and the effect is insufficient. On the other hand, when it exceeds 20 weight part, hardening is delayed and it is not preferable.

Examples of the conductive particles used in the present invention include metal particles such as gold, silver, copper, nickel, solder, carbon, and the like, and these may be used alone or in combination. Nickel powder is most preferred in view of conductivity, moisture resistance, heat resistance, and storage stability. It is also preferable that the particles are coated on the surface using an inorganic filler or a plastic as a nucleus. The average particle diameter of the conductive particles measured by the microtrack method is preferably 0.1 to 20 microns in terms of workability, dispersibility and conductivity.

The amount of the conductive particles added is preferably 100 to 1000 parts by weight, preferably 200 to 500 parts by weight based on 100 parts by weight of the resin composition obtained by blending the components of (1) to (4), in terms of workability and conductivity. If it is less than 100 parts by weight, the conductivity is insufficient, and if it exceeds 1000 parts by weight, workability is deteriorated and is not preferable.

Various additives, such as a filler, a diluent, a solvent, a pigment, a flexibility giver, a coupling agent, antioxidant, a thixotropic agent, a dispersing agent, can be added to the epoxy resin composition of this invention as needed.

Hereinafter, an Example is given and this invention is demonstrated in detail.

In addition, evaluation is carried out in the following manner.

Storage stability (life): The number of days until the fluidity | liquidity of the conductive resin composition preserve | saved in the 25 degreeC thermostat is measured.

Volume resistivity: The conductive resin composition is applied on a PET (polyethylene terephthalate) film about 50 microns thick, 3 mm wide and 150 mm long, cured at 80 ° C. for 30 minutes, and its volume resistivity is measured at 25 ° C.

Moisture resistance test: The cured product prepared by the above-described method is put in a constant temperature and humidity chamber at 60 ° C and 90%, and the change in volume resistivity over time is evaluated.

Heat resistance test: The hardened | cured material adjusted by the above-mentioned method is thrown into the constant temperature air tank of 100 degreeC, and the change of the volume resistivity with time is evaluated.

Example 1

6 parts by weight of tributyl borate is added to 100 parts by weight of bisphenol A type epoxy resin "EP-828" (trade name, manufactured by Yucca Shell Epoxy Co., Ltd.), followed by stirring and mixing. Next, 10 weight part of "Amicure PN-23" (brand name, product of Ajinomoto Co., Ltd.) is added as a solid dispersion type latent hardening accelerator, and it mixes well. Furthermore, 75 weight part of pentaerythritol tetrakistyopyropionate "EH317" (brand name, product made by Adeka Hardner Asahi Denka Kogyo Co., Ltd.) is added as a polythiol compound, and it fully vacuum-mixes with an all-purpose mixer, and manufactures a resin composition. . 400 weight part of nickel powders (average particle diameter: 3.5 micrometers) are mixed as conductive particle with respect to 100 weight part of such resin compositions, and it is set as the conductive resin composition for evaluation.

Example 2

6 parts by weight of triethyl borate is added to 100 parts by weight of bisphenol A type epoxy resin "EP-828" (trade name, manufactured by Yucca Shell Epoxy Co., Ltd.) and mixed. Subsequently, 10 weight part of "Fujicure FXE10OO" (brand name, manufactured by Fuji Chemical Co., Ltd.) is added as a solid dispersion type latent hardening accelerator, and it mixes well. Furthermore, 75 weight part of trimethylol propane tris ((beta) -thiopropionate) "TMTP" (brand name, product made from Yodogagaku Co., Ltd.) is added as a polythiol compound, and it fully vacuum-mixes with a universal mixer, and manufactures a resin composition. 400 parts of nickel powder (average particle diameter: 3.5 micrometers) are mixed as conductive particle with respect to 100 weight part of such resin compositions, and it is set as the conductive resin composition for evaluation.

Example 3

6 parts by weight of triethyl borate is added to 100 parts by weight of bisphenol AF-type epoxy resin "ZX-1059" (trade name, manufactured by Totogsei Co., Ltd.) and mixed well. Subsequently, 15 weight part of "Amicure PN-23" (brand name, Ajinomoto Co., Ltd. product) is added as a solid dispersion type latent hardening accelerator, and it mixes well. Furthermore, 80 weight part of trimethylol propane tris ((beta) -thiopropionate) "TMTP" (brand name, product made from Yodogagaku Co., Ltd.) is added as a polythiol compound, and it fully vacuum-mixes with a universal mixer, and manufactures a resin composition. 400 parts of nickel powder (average particle diameter: 3.5 micrometers) are mixed as conductive particle with respect to 100 weight part of such resin compositions, and it is set as the conductive resin composition for evaluation.

Example 4

6 parts by weight of tributyl borate is added to 100 parts by weight of bisphenol A type epoxy resin "EP-828" (trade name, manufactured by Yucca Shell Epoxy) and mixed well. Subsequently, 15 weight part of "Amicure PN-23" (brand name, Ajinomoto Co., Ltd. product) is added as a solid dispersion type latent hardening accelerator, and it mixes well. Furthermore, 80 weight part of trimethylol propane tris ((beta) -thiopropionate) "TMTP" (brand name, product made from Yodogagaku Co., Ltd.) is added as a polythiol compound, and it fully vacuum-mixes with an all-purpose mixer, and manufactures a resin composition. Nickel powder (average particle diameter: 3.5 µm), silver powder (average particle diameter: 7.0 µm), copper powder (average particle diameter: 15 µm), and carbon black (average particle diameter: 400 parts by weight of 1 µm) are respectively mixed to obtain a conductive resin composition for evaluation.

Comparative Example 1

Except not mixing a boric ester, it carried out similarly to Example 1, and prepares the electrically conductive resin composition for evaluation.

Comparative Example 2

Except not mixing polythiol, it carried out similarly to Example 1, and prepares the electrically conductive resin composition for evaluation. The results are shown in Table 1.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Volume resistance 10 ^-3 10 ^-3 10 ^-3 10 ^-3 Not measurable After 600 hours of invasion 10 ^-3 10 ^-3 10 ^-3 10 ^-3 After 600 hours of heat resistance 10 ^-2 10 ^-2 10 ^-2 10 ^-2 25 ℃ life More than 1 month More than 1 month More than 1 month 2 hours More than 1 month

In Examples 1 to 3, the initial volume resistance was 10 ⁻³ , and was maintained at 10 ⁻² or more even after 600 hours of the heat test and the moisture test. In addition, storage stability is also stable at 25 ℃ for more than one month. On the other hand, Comparative Example 1, in which no boric acid ester was added, is completely cured at about 2 hours after preparation. Comparative Example 2, in which no polythiol was added, had a low initial volume resistance and could not be measured.

Table 2 shows the evaluation results when changing the conductive particles according to Example 4.

Ni powder Ag powder Cu powder Carbon black Volume resistance 10 ^-3 10 ^-1 10 ^-3 2 to 3 After 600 hours of invasion 10 ^-2 10 ^-1 Impossible Impossible 25 ℃ life More than 1 month 10 days 7 days 14 days

As the conductive particles, nickel powder exhibited an initial volume resistivity of 10 ⁻³ and retained 10 ⁻² even after 60,000 hours of moisture resistance testing. However, silver powder has a large initial volume resistance, and copper powder is remarkably reduced after a moisture resistance test. Carbon black also significantly reduces the volume resistance after 600 hours and cannot be measured.

According to the present invention, it is possible to provide a conductive resin composition having a long life and improved storage stability. The resin composition has a volume resistivity of 10 ^-3 after heat curing and maintains the value even after 6 hours of heat resistance test and moisture resistance test. It is extremely useful and suitable for conductive materials in all fields including electronics where low temperature fast curing is required.

Claims (3)

An epoxy resin (1) having two or more epoxy groups in a molecule, a polythiol compound (2) having two or more thiol groups in a molecule, a solid dispersion latent curing accelerator (3), a boric acid ester compound (4), and conductive particles ( Conductive resin composition containing 5) as an essential component. The mixing ratio of the epoxy resin (1) and the polythiol compound (2) is 0.5 to 1.5 in terms of the number of SH equivalents of the polythiol compound / the epoxy equivalent number of the epoxy resin, and 100 parts by weight of the epoxy resin (1). With respect to the solid dispersion type latent curing accelerator (3), the added amount is 1 to 60 parts by weight, 0.1 to 20 parts by weight of the boric acid ester compound (4), and four components of components (1) to (4). Conductive resin composition formed by mix | blending 100-1000 weight part of conductive particles with respect to 100 weight part of compositions. The conductive resin composition according to claim 1 or 2, wherein the conductive particles are nickel powder.