JPH0472367A - Electrically conductive composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, containing copper powder, a thermosetting resin and a specific compound, excellent in electric conductivity, moisture and heat resistance and soldering properties and useful for printed circuits, etc. CONSTITUTION:The objective composition is obtained by containing (A) preferably 75-90wt.% copper powder (preferably 0.5-30mu particle diameter), (B) preferably 10-25wt.% thermosetting resin (e.g. epoxy resin or phenolic resin) and (C) a compound expressed by the formula (R1CO- is 1-22C acyl; R2 is H, 1-22C alkyl or alkenyl; n is 1-10) (e.g. caproylsarcosine or N-lauroyl-N-methyl-beta-2- alanine) in an amount of preferably 1.5-7.5 pts.wt. based on 100 pts. wt. total amount of the components (A) and (B). Furthermore, a diamine (e.g. lauroylpropylenediamine) is preferably contained therein.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a conductive composition, and more particularly, the present invention relates to a conductive composition that has excellent conductivity, moisture resistance, heat resistance, etc., and is extremely useful for printed circuits. The present invention relates to sexual compositions.

<Prior Art> Conventionally, in the field of electronic components, conductive compositions containing noble metals such as gold and silver as main components have been widely used as conductive compositions for printed circuits. In particular, silver is frequently used because it is a metal with the lowest volume resistivity, has electrical conductivity even when oxidized, and is relatively inexpensive among noble metals.

However, when a printed circuit is formed using a conductive composition containing silver as a main component, for example, when the line spacing of the circuit is narrow and the potential difference is large, a migration phenomenon of silver occurs and the resistance of the circuit increases. The disadvantage is that an increase in the voltage and even a short circuit can occur. Furthermore, in recent years, cost reduction has been emphasized in the electronic parts industry, and relatively inexpensive silver has been problematic in terms of cost.

Recently, silver has the lowest volume resistivity after silver.

Moreover, various studies have been made to develop conductive compositions containing copper as a main component, which is cheaper than silver. However, since the copper powder in the conductive composition has a large oxidation property, it is difficult to use when storing the conductive composition, when forming circuits such as printing and heating, and even when forming circuits. During use, the surface of the copper powder is oxidized, the contact resistance between the copper powder particles increases, and there is a drawback that sufficient conductivity cannot be obtained. Therefore, in order to solve the drawbacks of copper powder, it has been proposed to add various additives to conductive compositions containing copper as a main component. Examples of such additives include phosphorous acid or its derivatives in Japanese Patent Publication No. 52-24936, anthracene or its derivatives in Japanese Patent Publication No. 61-36796, and Japanese Patent Publication No. 57-55974 , derivatives of hydroquinones have been proposed. but,
At present, the specific resistance value of a coating film obtained from a conductive composition containing the above-mentioned additives is about 10<-3 >[Omega].alpha., which is not sufficient. Furthermore, JP-A-61-211378 discloses unsaturated fatty acids, JP-A-61-14175 discloses fatty acid amides, JP-A-61-200179 discloses higher aliphatic amines, and JP-A-61-200179 discloses higher aliphatic amines. No. 225168 proposes a conductive composition using a phenylenediamine derivative as an additive. Although the specific resistance value of the coating film obtained with the conductive composition has been improved to about 10-'Ω・α, the resistance value increases rapidly when the coating film is left under high humidity, and furthermore, the resistance value increases over a long period of time. The drawback is that stability cannot be expected.

<Problems to be Solved by the Invention> Therefore, the main object of the present invention is to provide a conductive composition that has excellent conductivity, heat resistance, moisture resistance, robustness, etc., and is capable of forming printed circuits, etc. It's about doing.

Means for Solving the Problems> According to the present invention, (a) copper powder, (b) thermosetting resin, and (c) the following general formula (I) (wherein R1Co- is a carbon number of 1 to 22 represents an acyl group, R2 represents a hydrogen atom or an alkyl group or alkenyl group having 1 to 22 carbon atoms, and n represents an integer of 1 to 10), and optionally (d) diamine. Provided is a conductive composition containing the following.

The present invention will be explained in more detail below.

The copper powder used in the conductive composition of the present invention is not particularly limited, but includes, for example, electrolytic copper powder, reduced copper powder obtained by reducing cuprous oxide, cupric oxide, etc., and atomized copper powder. , pulverized metal copper, etc. can be preferably mentioned. The particle size of the copper powder is 0.5 to 100μ, particularly 0.5 to 30μ.
It is preferable that it is in the range of . If the particle size exceeds 100μ, problems will occur in printability, and if the particle size is less than 0.5μ,
This is not preferred because the copper powder is easily oxidized and the conductivity of the resulting coating film is reduced.

Examples of the thermosetting resin (b) used in the conductive composition of the present invention include epoxy resin, urea resin, melamine resin,
Preferred examples include phenol resins, unsaturated polyester resins, alkyd resins, allyl resins such as diallyl phthalate, thermosetting urethane resins, and polyimide resins.

In the present invention, the blending ratio of the (a) copper powder and (b) thermosetting resin is preferably 65 to 9.
% Sfi, particularly preferably 75-90% by weight, i.e. (
b) 5 to 35% by weight of thermosetting resin, particularly preferably 10
Preferably it is 25% by weight. If the blending ratio of the copper powder (a) is less than 65% by weight, the specific resistance required for a conductive circuit cannot be obtained, and if it exceeds 95% by weight, the physical properties of the paste, such as printability, may deteriorate. This is not preferable because it lowers the temperature.

The compound (c) used in the conductive composition of the present invention can be represented by the following general formula (1).

In the formula, R, CO- represents an acyl group having 1 to 22 carbon atoms,
R2 represents a hydrogen atom or an alkyl group or alkenyl group having 1 to 22 carbon atoms. Moreover, n represents an integer of 1 to 10. When R and C〇- are an acyl group having more than 22 carbon atoms, when R2 is an alkyl group or alkenyl group having more than 22 carbon atoms, or when n is more than 10, it is difficult to manufacture any of them. Specific examples of the compound (c) represented by the general formula (1) include caproylsarcosine, lauroylsarcosine, myristoylsarcosine, balmitoylsarcosine, stearoylsarcosine, oleoylsarcosine, behenoylsarcosine, etc. N-acyl sarcosine modified from higher fatty acids, or mixed fatty acid sarcosine such as coconut oil fatty acid sarcosine, tall oil fatty acid sarcosine, N-lauroyl-N-methyl-β-alanine,
N-oleoyl-N-methyl-β-alanine, N-cocoyl-N-methyl-β-alanine, N-caproyl-N
-Methyl-β-alanine, N-myristoyl-N-methyl-β-alanine, N-valmitoyl-N-methyl-β
Preferred examples include -alanine, N-stearoyl-N-methyl-β-alanine, and N-behenyl-N-methyl-β-alanine. The compounding amount of the compound is preferably 0.5 to 10 parts by weight, particularly preferably 1.5 to 7.5 parts by weight, based on 100 parts by weight of the total amount of the copper powder and thermosetting resin. It is preferable to have one.

If the amount is less than 0.5 parts by weight, various effects cannot be obtained by addition, and if it exceeds 10 parts by weight, it will have an adverse effect on the physical properties of the conductive composition, which is not preferable.

In the conductive composition of the present invention, (d) diamine, which can be contained as necessary, is a component that further improves conductivity, heat resistance, and moisture resistance, such as aliphatic diamine, aromatic diamine, etc. Examples of aliphatic diamines include lauroylpropylene diamine, balmitoylpropylene diamine, stearylpropylene diamine, oleylpropylene diamine, etc.
In addition, aromatic diamines include 0-phenylenediamine,
m-phenylenediamine, p-phenylenediamine, 4
-(4-sulfobenzyl)aminoaniline, 4-dimethylaminoaniline, 4-diethylaminoaniline, 2-
Amino-5-diethylaminotoluene, 4-[N-(
β-hydroxyethyl)aminocoaniline, 4-[N
, N-di(β-hydroxyethyl)aminocoaniline, and the like. The amount of the diamine (d) to be incorporated is preferably 100 to 1 part by weight per 100 parts by weight of the compound represented by the general formula (1) (c).
000 parts by weight, particularly preferably from 500 to 1000 parts by weight. If the amount of diamine added is less than 100 parts by weight, the desired effect cannot be obtained by adding the diamine, and if it exceeds 1000 parts by weight, heat resistance and moisture resistance will decrease, which is not preferable.

To prepare the conductive composition of the present invention, 1, for example, the above (a)
) copper powder, (b) thermosetting resin and the above (c) general formula (
The compound represented by 1) can be obtained by mixing and kneading (d) diamine if necessary. Further, when preparing the composition, it is also possible to add a viscosity modifier such as butylcarpitol, an antifoaming agent, a thickener, an anti-scaling agent, etc., if necessary.

<Effects of the Invention> Since the conductive composition of the present invention has copper and a thermosetting resin as its main components, it is cheaper in cost than conventional conductive compositions whose main components are silver or gold. Yes, and the above general formula (
Since it contains the compound represented by I) and further a diamine if necessary, excellent conductivity can be stably obtained even under harsh environments of high temperature and high humidity. Therefore,
For example, by baking and curing the conductive composition of the present invention on an insulating substrate, it is possible to produce printed circuits and the like that are extremely excellent in conductivity, heat resistance, moisture resistance, and solderability.

<Examples> The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

In addition, parts in the examples indicate parts by weight.

85 parts of atomized copper powder with an average particle size of 8μ, 15 parts of phenol resin (trade name rBLS-364HJ manufactured by Showa Kobunshi Co., Ltd., non-volatile content 65%), 2 parts of lauroyl sarcosine
．． 5 parts and 5 parts of butylcarpitol were thoroughly mixed and dispersed. Next, the resulting composition was printed on a glass-epoxy substrate with a pattern for resistance value measurement with 21 lines and a length of 368 m using a 250-mesh Tetron screen, and then placed in a constant temperature bath maintained at 160°C. The film was heated for 30 minutes in a baking oven to harden the film. Regarding the obtained cured sample,
The initial resistance value was measured using a digital multimeter, and the film thickness of the printed circuit was also measured to calculate the initial specific resistance value. As a result, the initial resistance value and initial specific resistance value were 4.4Ω, respectively.
It was 6.0×10-'Ω・mouth. In addition, in order to evaluate moisture resistance, the cured sample was kept in a constant temperature and humidity chamber at 60° C. and 95% RH for 1000 hours, and then the specific resistance value was similarly calculated. It was lX10-'Ω·1.

Further, in order to evaluate heat resistance, the cured sample was kept in a constant temperature bath at 85° C. for 1000 hours, and then the specific resistance value was similarly calculated and found to be 6.6XIO-'Ω·l. Furthermore, in order to evaluate the soldering heat resistance, the cured sample was immersed in a solder bath at 260'C for 10 seconds, and the specific resistance value was similarly calculated to be 8.0x10'Ω·l. Table 1 shows the type of compound (C), the initial resistivity value, and the resistivity value after moisture resistance, heat resistance, and soldering heat resistance tests.

Examples 2-8, Comparisons 1-4 Compound 2 shown in Table 1 instead of lauroylsarcosine
．． A composition was prepared in the same manner as in Example 1, except that 5 parts were used, and each measurement was performed. The results are shown in Table 1.

A composition was prepared in the same manner as in Example 1, except that 2.5 parts of a mixture of 100 parts of coconut oil fatty acid sarcosine and 700 parts of oleylpropylene diamine was used instead of lauroyl sarcosine. Measurements were made. The results are shown in Table 1.

Lost bonito ↓ Instead of standing lauroyl sarcosine, N-lauroyl-N
-A composition was prepared in the same manner as in Example 1, except that 2.5 parts of a mixture of 100 parts of methyl-β-alanine and 800 parts of P-phinyl diamine was used, and each measurement was performed. . The results are shown in Table 1.

Claims (1)

[Claims] 1) (a) copper powder, (b) thermosetting resin, and (c) the following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R_1CO- is , represents an acyl group having 1 to 22 carbon atoms, R_2 represents a hydrogen atom or an alkyl group or alkenyl group having 1 to 22 carbon atoms, and n represents an integer of 1 to 10). A conductive composition. 2) The conductive composition according to claim 1, further comprising (d) a diamine.