JPH01132652A - Conductive resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which excels in room temperature shelf life and can cure rapidly at a high temperature to give a cured product of excellent properties, by mixing a conductive filler with an epoxy resin, an acid anhydride and a specified latent cure accelerator. CONSTITUTION:An adduct obtained by adding a di(substituted) alkylamine (e.g., dimethylamine) to a solution of an epoxy compound (e.g., butyl glycidyl ether) in a solvent of a b.p. >=50 deg.C (e.g., acetone) and reacting them by heating is ground and optionally treated with an acidic substance to obtain a latent cure accelerator (D). An epoxy resin (A) is mixed with 30-95wt.% conductive filler (B) (e.g., graphite), an acid anhydride (C) (e.g., phthalic anhydride) and 0.1-10wt.%, based on component A, component D.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a conductive resin composition. More specifically, the present invention is an adhesive for bonding lead wires of integrated circuits, high voltage ICs, etc., adhesives for mounting various parts, plastics for electromagnetic shielding of electronic equipment, paints, etc., and adhesives for parts that require conductivity. The present invention relates to a conductive resin composition suitable for use in plastic materials, paints, etc.

(Prior art) Conductive resin compositions include phenolic resin, acrylic resin,
It is made into a paste by mixing a conductive filler with a synthetic resin such as alkyd resin, epoxy resin, or polyimide resin, and epoxy resin is usually used frequently. Currently, conductive epoxy resin compositions commonly used include two-component types, in which a base resin containing an epoxy resin containing a conductive filler and a curing agent are mixed immediately before use; There is also a one-component type that is pre-blended with a drug. As the two-component type curing agent, polyamide resins or amines are generally used, and as the -wave type curing agent, phenol resins, imidazole compounds, nocyancyamide and urea compounds, etc. are used.

(Problems to be Solved by the Invention) In conventional two-component conductive resin compositions, when the base resin and curing agent are mixed, the viscosity increases rapidly and the composition hardens in a few hours to a few days, making it unusable. Time is short.

In addition, in molded conductive resin compositions, the curing agent gradually dissolves at room temperature and reacts with the epoxy resin, increasing the viscosity over time and curing in about a few days to two weeks. It has poor storage stability, and must be stored at a low temperature of 0 to 5°C when not in use or for long-term storage, and must be transported frozen. As described above, conventional conductive resin compositions are not practically satisfactory in terms of pot life, storage stability, etc.

The present inventors have studied to improve the shortcomings of such conductive epoxy resin compositions, and have developed an epoxy resin composition that has excellent storage stability at room temperature, quickly cures at high temperatures, and yields a conductive cured product with excellent physical properties. I got something.

That is, an object of the present invention is to improve the storage stability of a conductive epoxy resin composition, and furthermore, to provide an excellent single-wave conductive epoxy resin composition that satisfies both room temperature storage stability and curability. It is about providing something.

(Means for Solving the Problems) The present invention is produced by reacting a conductive filler, an epoxy resin, an acid anhydride curing agent, and an epoxy compound with a dialkylamine (furkyl group may be substituted). It is characterized by a conductive resin composition whose main component is a latent curing accelerator made of powdered addition compound.

Furthermore, the second invention uses dialkylamine (
, the furkyl group may be substituted) is characterized by a conductive resin composition whose main component is a latent curing accelerator, which is obtained by treating the powder surface of an addition compound obtained by reacting with an acidic substance. .

The conductive resin composition according to the present invention will be explained in detail below.

The epoxy resin used in the present invention has two or more glycidyl groups per molecule on average, such as bisphenol A, bisphenol F1, bisphenol AD, etc.
, catechol, polyhydric phenol such as resorcinol, or polyglycidyl ether obtained by reacting epichlorohydrin with polyhydric alcohol such as glycerin or polyethylene glycol, or P-oxybenzoic acid, β
- Glycidyl ether ester obtained by reacting a hydroxycarboxylic acid such as oxynaphthoic acid with epichlorohydrin, or a polyglycidyl ester obtained from a polycarboxylic acid such as dimer acid or heptatalic acid,
Alternatively, 4,4'-di7mi/nophenylmethane or 1-
7 Glycidylamine compound obtained from minophenol etc., 3,4-epoxycyclohexylmethyl-3,4-
Examples include cycloaliphatic epoxy compounds such as epoxycyclohexanecarboxylate, 3.4-epoxy-6-methylcyclohexylmethyl-3゜4-epoxy-6-methylcyclohexanecarboxylate, as well as epoxidized novolak and epoxidized polyolefin. However,
It is not limited to these.

As the acid anhydride of the curing agent used in the present invention, those conventionally used for curing epoxy resins can be used, such as 7-talic anhydride, 7-talic anhydride, tetrahydro-7-talic anhydride,
hexahydro anhydride 7 talic acid, methyl hexahydro anhydride 7
Examples include tarric acid, maleic anhydride, pyromellitic anhydride, methyl nanotullic anhydride, methylbutenyltetrahydro7talic anhydride, methyltetrahydro7tallic anhydride pH, and the like.

Examples of the dialkylamine that can be used as a raw material for the addition compound used in the present invention include trimethylamine, diethylamine, nobrobilamine, N-methylethylamine, N-
Examples include ethylisobutylamine, noallylamine, dibenzylamine, N-ethylethanolamine, and ethanolamine. The epoxy compounds to be reacted with these dialkylamines are not particularly limited, but include monoepoxy compounds typified by butyl glycidyl ether and phenyl glycidyl ether, polyhydric phenols, polyhydric carboxylic acids, etc. as exemplified above. Examples include epoxy 84N obtained from amine necks, and by mixing one or more of these epoxy compounds, an addition compound with any softening point can be obtained. A dialkylamine addition compound of an epoxy compound can be easily obtained by dissolving the epoxy compound in solution M, mixing excess dialkylamine and reacting while heating, and after the reaction is completed, distilling off the unreacted amine and solvent. .

Suitable solvents are those with a boiling point of 50°C or higher that can dissolve the epoxy compound, such as tetrahydro7ran, dioxane, acetone, methyl ethyl ketone, toluene, monochlorobenzene, methyl cellosolve, ethyl cellosolve, among others, ethyl cellosolve and toluene. Preferably, the 1° addition compound can be ground into powder using an atomizer, for example, to form the latent hardening accelerator M used in the present invention. 2. The surface of the addition compound powder can be treated with an acidic substance by exposing the powder to a gaseous acid or by dispersing it in a dilute acidic substance solution and then drying it.

Acidic substances used for surface treatment include gaseous and liquid inorganic and organic acids such as sulfur dioxide gas, hydrochloric acid, carbon dioxide gas,
Sulfuric acid, phosphoric acid, oxalic acid, formic acid, oxalic acid, acetic acid, 70 pionic acid, lactic acid, cabucunic acid, salicylic acid, tartaric acid, succinic acid, adipic acid, cepatic acid, p-)luenesulfonic acid,
Examples include phenol, pyrogallol, tannic acid, lonone, polyacrylic acid, polymethacrylic acid, alginic acid, phenol IfN, and resorcinol resin.

The amount of these acidic substances to be used should be sufficient to neutralize the amine 7 groups exposed on the powder surface of the adduct; if the amount is too large, the effect of accelerating the curing of the epoxy resin may be reduced. There is a risk of inviting Therefore, it is preferable to quantify the amine in advance using a portion of the sample to determine the necessary amount before treatment.

Examples of the conductive filler used in the present invention include metal powders such as gold, silver, platinum, nickel, palladium, copper, aluminum, and iron, powders such as carbon black and graphite, and carbon fibers. Can be done. In addition, there are metal powders such as iron, copper, and nickel, carbon powders, glass powders, and glass 7 fibers whose surfaces are coated with highly conductive metals such as gold and silver.

These conductive fillers can be used alone or in combination depending on the required conductivity and purpose, and the type, shape, and size of the conductive filler depend on the purpose of use of the conductive resin composition. can be selected as appropriate.

The conductivity of the present invention mW! The composition includes epoxy resin, conductive filler, and 1! ! It can be easily obtained by uniformly mixing the anhydride curing agent and the latent curing accelerator.

In this case, the amount of latent curing accelerator used may be 0.1 to 10% by weight based on the epoxy resin, especially 1.0 to 10% by weight.
3.0% by weight gives good results. *The amount of the conductive filler used is 30 to 95% by weight of the conductive resin composition of the present invention,
Among them, it is preferable to use 50 to 90% by weight.If the amount of conductive filler used is less than 30% by weight, almost no practical conductivity will be obtained, and if it exceeds 95% by weight, the coating properties will deteriorate.
Adhesive strength etc. will be significantly reduced.

The conductive resin composition of the present invention may contain additives used in ordinary epoxy resin compositions, such as solvents, colorants, viscosity modifiers, fillers, etc., as long as they do not adversely affect storage stability, curability, etc. There is no problem in blending modifiers and the like having various purposes, and these blends also meet the purpose of the present invention and are included within its scope.

(Effect of the invention) The conductive epoxy tree JI of the present invention obtained in this way
B-type has excellent storage stability at room temperature, can be stored for more than one month even in summer, and has greatly improved curing properties compared to conventional one-wave epoxy UF compositions, making it a good product. Provides a conductive cured product with performance. Therefore, in advance,
- The advantage is that the resin can be adjusted and stored at the same time, and unlike the two-part type, there is no need for complicated operations each time. r7. There is.

(Example) The present invention will be described below with reference to examples, but the scope of the present invention is not limited by these examples. "1 part in 0 examples" indicates part by ffi amount.

[Latent curing accelerator! ! ! example〕

Production example 1 Sumiepoxy ESCN-22OL (Sumie Chemical Industry Co., Ltd.)
Made of cresol novolak type epoxy resin.

Softening point: 70°C, epoxy equivalent: 212) 150 parts to 400 parts
Dissolve in 10 g of ethyl cellosolve and heat with stirring for 10
0 parts of an aqueous dimethylamine solution (40%) are added dropwise as soon as possible. After reacting at 50 to 80°C for 3 hours, unreacted amine and solvent are heated at 100 to 160°C and distilled off under reduced pressure.1 Next, the reactants are dissolved in 150 parts of toluene, and similarly distilled off under reduced pressure to obtain If. By distilling off the unreacted amine in l1tt, 170 parts of adduct was obtained. After the adduct was pulverized with an atomizer, it was pulverized with a jet pulverizer to obtain a fine powder with a particle size of 1 to 20 μm. This is referred to as a latent curing accelerator (1).

Production Example 2 75 parts of Sumiepoxy ESCN-220L and Sumiepoxy ESA-011 (Ebibis type epoxy resin manufactured by Sumitomo Kagaku Kogyo Co., Ltd. Softening point: 69°C [489°] per epoxy) 75g
was dissolved in 600 parts of ethyl cellosolve, and 190 parts of a dimethylamine aqueous solution (40%) was added dropwise as soon as possible while stirring under heating. Thereafter, the same procedure as in Production Example 1 was carried out to obtain 180 parts of a fine powder adduct. This is added as a latent curing accelerator (
2).

5i! Example 3 130 parts of Sumiepoxy ESA-017 (Ebibis type epoxy resin manufactured by Sumitomo Chemical Co., Ltd., softened, +?, 130″C, epoxy equivalent 1830.) and Sumiepoxy ELA
20 parts of -134 (Sumiman Chemical Co., Ltd. Epibis type Evokin tree, softening point 22°C, epoxy equivalent 244°) was dissolved in 500 parts of ethyl cellosolve and treated in the same manner as in Production Example 1 to obtain 120 parts of ethyl amine. Cellosolve solution (
40%) to obtain 152 parts of a fine powder adduct. This is referred to as a latent curing accelerator (3).

Production Example 4 50g of the fine powder adduct obtained in Production Example 1 was placed in a sealed container,
A large amount of hydrochloric acid was blown into the mixture, and the mixture was left at room temperature overnight. Excess salt Wl〃was replaced with air to obtain 48 parts of fine powder.

This is referred to as a latent curing accelerator (4).

Production Example 5 50 parts of the fine powder adduct obtained in Example 1 was dispersed in 150 parts of water. Add 150% of 0.5% tartaric acid aqueous solution to this dispersion.
1 part was added dropwise while stirring. After stirring for 30 minutes! The mixture was filtered and dried under reduced pressure to obtain 48 parts of fine powder. This is referred to as a latent curing accelerator (5).

Production Example 6 While stirring a dispersion of 50 parts of the fine powder adduct obtained in Production Example 2 in 150 parts of water, 15% of a 0.3% formic acid aqueous solution was added.
0 parts were added dropwise. The mixture was stirred for 30 minutes, filtered through amperage, and dried under reduced pressure to obtain 46 parts of fine powder.

This is referred to as a latent curing accelerator (6).

Production Example 7 100 parts of the fine powder adduct obtained in Production Example 3 was dispersed in 300 parts of water, and the same procedure as in Production Example 3 was carried out to obtain 0°65% p-).
Treated with 380 parts of luenesulfonic acid aqueous solution, 95+￥l
A fine powder of s was obtained. This is referred to as a latent curing accelerator (7).

Examples 1 to 12, Comparative Examples 1 to 12 Nipico-) 828 (Yuka Shell Epoxy Co., Ltd. screw 7)
Table 1 was prepared by using the conductive filler shown in Table 1, the acid anhydride curing agent and the latent curing accelerator obtained in Production Examples 1 to 7. A conductive tree layer composition was prepared with the composition shown below. In Examples 1.2.3.7.8 and 9, a latent curing accelerator and then a conductive filler were added and mixed into a premixed mixture of an epoxy resin and an acid anhydride curing agent. In Examples 4, 5, 6, 10, 11, and 12, the epoxy resin and the latent curing accelerator were mixed first, and then the acid anhydride curing agent and the conductive filler were mixed. Using these compositions, curing time, heat distortion temperature, and storage stability of the compositions were measured. The sinus results are shown in Table 1.

The curing time was measured using a hot plate sol timer (Nissinka '7?).
Co., Ltd.). Storage stability was measured by determining the oral change in viscosity. Heat distortion temperature is 100'CX 2H
The cured product was further cured at 130° C.

The conductivity was determined by printing on an alumina substrate with a film thickness of 40 μm.
The sheet resistance value of the film cured at 60 minutes at ℃ was measured, and the specific resistance was calculated from the sheet resistance value and the film thickness.

Table 2 shows, as a comparative example to the above example, that Epikote 828 was used instead of using the latent curing accelerator of the present invention.
In contrast, conductive resin compositions were produced using various curing agents shown in Table 2, and the results of curing time, heat distortion temperature, and storage stability are shown.

Patent applicant: Taoka Kagaku Komata Co., Ltd. Patent applicant: Kayabae Gyo Co., Ltd.

Claims (1)

[Claims] 1. Powdering of an addition compound obtained by reacting a conductive filler, an epoxy resin, an acid anhydride curing agent, and an epoxy compound with a dialkylamine (the alkyl group may be substituted) A conductive resin composition whose main component is a latent curing accelerator. 2. The powder surface of the addition compound obtained by reacting the conductive filler, epoxy resin, acid anhydride curing agent, and epoxy compound with dialkylamine (the alkyl group may be substituted) is treated with an acidic substance. A conductive resin composition whose main component is a latent curing accelerator.