JPH0649272A - Electrically conductive composition - Google Patents

Abstract

PURPOSE:To provide an electrically conductive composition excellent in heat resistance, moisture resistance and soldering heat resistance, useful for printed circuits, etc., comprising a specific compound, a specific polyamine, copper powder, and a thermosetting resin. CONSTITUTION:The composition comprising (A) pref. 75-90wt.% of copper powder 0.5-30mum in particle diameter (e.g. electrolytic copper powder), (B) pref. 10-25wt.% of a thermosetting resin such as an epoxy resin, (C) pref. 0.5-5.0 pts.wt., based on a total of 100 pts.wt. of the components A and B, of a compound of the formula (R1 is 1-8C alkyl; R2 is 1-4C alkyl; R3 is H or 1-8C alkyl), and (D) pref. 30-300 pts.wt. based on 100 pts.wt. of the component C, of a polyamine having in one molecule at least 3 nitrogen atoms and 80-30000 in weight-average molecular weight (e.g. 1,2,3-triaminopropane).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a conductive composition,
More specifically, the present invention relates to a conductive composition which is excellent in conductivity, moisture resistance, heat resistance, solder heat resistance and the like and is extremely useful for printed circuits and the like.

[0002]

2. Description of the Related Art Conventionally, in the field of electronic components, as a conductive composition for a printed circuit, a conductive composition containing a noble metal such as gold and silver as a main component has been widely used. Particularly, silver is widely used because it has the lowest volume specific resistance, has conductivity even when oxidized, and is relatively inexpensive among noble metals.

However, when a printed circuit is formed from 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 silver migration phenomenon occurs and the circuit However, there is a drawback that the resistance is increased and a short circuit occurs in the circuit. In recent years, cost reduction has been emphasized in the electronic component industry, and even relatively inexpensive silver has a cost problem.

Therefore, recently, various studies have been made on the development of a conductive composition containing copper as a main component, which has the second lowest volume resistivity after silver and is cheaper than silver. However, since the copper powder in the conductive composition has a large oxidizability, it is necessary to store the conductive composition, form a circuit such as printing and heating, or use the formed circuit. At times, the surface of the copper powder is oxidized, the contact resistance between the copper powder particles increases, and sufficient conductivity cannot be obtained. Therefore,
In order to solve the drawbacks of such a copper powder, it has been proposed to add various additives to a conductive composition containing copper as a main component. Examples of the additive include phosphorous acid or a derivative thereof in JP-B-52-24936, anthracene or a derivative thereof in JP-B-61-37696, and JP-A-57-55974. , Derivatives of hydroquinones have been proposed. However, under the present circumstances, the specific resistance value of a coating film obtained from a conductive composition containing the above-mentioned additive is not sufficient at about 10 to ³ Ω · cm. Unsaturated fatty acids are disclosed in JP-A-61-211378, fatty acid amides are disclosed in JP-B-61-14175, higher aliphatic amines are disclosed in JP-A-61-210079, and JP-A-58-58. Japanese Patent No. 225168 proposes a conductive composition using a phenylenediamine derivative as an additive. Although the specific resistance value of the coating film obtained from the conductive composition has been improved to about 10 to ⁴ Ω · cm, when the coating film is left under high humidity, the resistance value rapidly increases, and the long-term It has the drawback that stability cannot be expected.

[0005]

Therefore, a main object of the present invention is to provide a conductive composition which is excellent in conductivity, heat resistance, moisture resistance, solder heat resistance and the like and which can form a printed circuit and the like. To provide.

[0006]

According to the present invention, (a)
Copper powder, (b) thermosetting resin, (c) compound represented by the following general formula 2 (hereinafter referred to as compound (c)) and (d) having 3 or more nitrogen atoms in one molecule, and Provided is a conductive composition containing a polyamine having a weight average molecular weight of 80 to 30,000.

[0007]

[Chemical 2]

The present invention will be described in more detail below.

The (a) copper powder used in the conductive composition of the present invention is not particularly limited, but for example, reduced copper powder obtained by reducing electrolytic copper powder, cuprous oxide, cupric oxide, etc., Preferable are atomized copper powder, pulverized metal copper and the like. The particle size of the copper powder is preferably 0.5 to 100 μm, particularly preferably 0.5 to 30 μm. Particle size is 1
When it is more than 00 μm, there is a problem in printability, and when it is less than 0.5 μm, the copper powder is easily oxidized and the conductivity of the obtained coating film is lowered, which is not preferable.

Examples of the thermosetting resin (b) used in the conductive composition of the present invention include epoxy resin, urea resin, melamine resin, "BLS-364H" (trade name, manufactured by Showa High Polymer Co., Ltd.). Phenol resin, unsaturated polyester resin, alkyd resin, allyl resin such as diallyl phthalate, thermosetting urethane resin, polyimide resin and the like can be preferably mentioned.

In the present invention, (a) the copper powder,
The blending ratio with the (b) thermosetting resin is preferably (a).
It is desirable that the amount of the copper powder is 65 to 95% by weight, particularly preferably 75 to 90% by weight, that is, the thermosetting resin (b) is 5 to 35% by weight, particularly preferably 10 to 25% by weight. If the compounding ratio of the (a) copper powder is less than 65% by weight, the specific resistance required for a conductive circuit cannot be obtained, and the content is 95% by weight.
If it exceeds the range, the physical properties of the paste when printing, etc., are reduced, which is not preferable.

The compound (c) used in the conductive composition of the present invention can be represented by the above general formula 2, wherein R is
_{When 1} is an alkyl group having more than 9 carbon atoms, R ₂ is an alkyl group having more than 5 carbon atoms, and R ₃ is an alkyl group having more than 9 carbon atoms, it is difficult to produce them. The compound (c)
Specifically, for example, 2,2'-methylenebis (4-methyl-6-ethylphenol), 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-
Butylphenol), 2,2'-ethylenebis (4-methyl-6-t-butylphenol), 2,2'-butylidenebis (4-methyl-6-t-butylphenol),
Preferred examples include 2,2′-butylidene bis (4-ethyl-6-ethylphenol) and the like. The compound (c) is blended in an amount of preferably 0.3 to 10 parts by weight, particularly preferably 0.5 to 5.0 parts by weight, based on 100 parts by weight of the total amount of the copper powder and the thermosetting resin. Parts by weight. If the content is less than 0.3 parts by weight, the effect of conductivity due to addition cannot be obtained, and if it exceeds 10 parts by weight, the physical properties of the conductive composition are adversely affected, which is not preferable.

The polyamine (d) used in the present invention is a component for further improving the conductivity, heat resistance and moisture resistance of the conductive composition, and has 3 or more nitrogen atoms in one molecule, and It is a compound having a weight average molecular weight of 80 to 30,000. When the weight average molecular weight is less than 80, there is little effect of improving the conductivity, and further problems such as inferior moisture resistance occur, and when it exceeds 30,000, the compatibility with the resin is inferior and the electroconductive composition is used. Since the long-term stability as is not good, it must be within the above range. Examples of the polyamine include 1,2,3-triaminopropane, tris (2-aminoethyl) amine, tetra (aminomethyl)
Alkyl polyamines such as methane, iminobispropylamine, methyliminobispropylamine; diethylenetriamine, triethylenetetramine, tetraethylenepentamine, heptaethyleneoctamine, nonaethylenedecamine, trade name "Montrec" (Dow Chemical Company ), Product name "Epomin SP003""EpominSP006""EpominSP012""EpominSP018""EpominSP200"
"Epomin SP300""EpominSP103""Epomin SP11
Preferable examples include polyethyleneimines such as 0 "(manufactured by Nippon Shokubai Chemical Co., Ltd.); polyethylenepolyamines such as triethylenetetramine, dipropylenetriamine, tripropylenetetramine, tetrapropylpentamine, and heptapropyloctamine. You can The compounding amount of the (d) polyamine is the compound (c) 10
The amount is preferably 10 to 500 parts by weight, particularly preferably 30 to 300 parts by weight, based on 0 parts by weight. When the amount of the polyamine is less than 10 parts by weight, the conductivity is lowered and the adhesion with the copper foil is lowered, and the desired effect due to the addition of the polyamine cannot be obtained, and when it exceeds 500 parts by weight. It is not preferable because the heat resistance and the humidity resistance are deteriorated and the leather is skinned.

To prepare the conductive composition of the present invention, for example, a mixture of the above (a) copper powder and (b) thermosetting resin and a mixture of the above compounds (c) and (d) polyamine are mixed. It can be obtained by kneading. Further, when preparing the composition, it is possible to add a viscosity modifier such as methyl carbitol, an antifoaming agent, a thickener, an anti-skin agent, etc., if necessary.

[0015]

Since the conductive composition of the present invention contains copper and a thermosetting resin as main components, it is less costly than a conventional conductive composition containing silver or gold as a main component. Moreover, since the compound (c) and the polyamine are contained, excellent conductivity can be stably obtained even in a severe environment 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 manufacture a printed circuit or the like having extremely excellent conductivity, heat resistance, moisture resistance, and solder heat resistance.

[0016]

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

The parts in the examples are parts by weight.

[0018]

Example 1 82 parts of electrolytic copper powder having an average particle size of 8 μm, 18 parts of phenol resin (trade name “BLS-364H” manufactured by Showa Polymer Co., Ltd., nonvolatile content 65%), and 2,2′-methylenebis ( 4-methyl-6-t-butylphenol)
2 parts of a mixture obtained by mixing 100 parts of polyethyleneimine (molecular weight 300, trade name "Epomin SP103" manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.) with 8 parts of methyl carbitol was sufficiently mixed and dispersed. Then, the obtained composition was printed on a glass-epoxy substrate with a resistance measuring pattern having a width of 2 mm and a length of 368 mm using a 150-mesh stainless screen, and then in a constant temperature bath kept at 160 ° C. It was heated for 30 minutes, baked and cured, and a solder resist was printed and cured thereon. For the obtained cured sample, the initial resistance value was measured with a digital multimeter,
Further, the film thickness of the printed circuit was measured to calculate the initial specific resistance value. As a result, the initial specific resistance value is 1.1 × 10 to ⁴ Ω · cm.
Met. In addition, in order to evaluate the moisture resistance, 60 ° C, 95
After the cured sample was held in a thermo-hygrostat of% RH for 1000 hours, the resistance change rate was calculated to be 56%. Further, in order to evaluate the heat resistance, the rate of change in resistance was calculated in the same manner after holding the cured sample in a constant temperature bath at 85 ° C. for 1000 hours, and it was 29%. Furthermore, in order to evaluate the solder heat resistance, immersion of the cured sample in a solder bath at 260 ° C. for 10 seconds was repeated 3 times, and then the resistance change rate was calculated in the same manner to be −11%. Table 1 shows the type of compound (c), the initial specific resistance value, the resistance change rate after the moisture resistance / heat resistance and the solder heat resistance test.

The initial specific resistance value and the rate of change in resistance were calculated based on the following equations. -Initial specific resistance value = volume specific resistance value-Ratio of resistance change (%) = ((resistance value after test)-(initial resistance value)) / (initial resistance value) x 100

[0020]

Examples 2 to 5, Comparative Examples 1 to 2 Instead of the mixture of 2,2'-methylenebis (4-methyl-6-t-butylphenol) and polyethyleneimine, 2 parts of the compounds shown in Table 1 were used. A composition was prepared and each measurement was performed in the same manner as in Example 1 except that the above was used. The results are shown in Table 1.

[0021]

[Table 1]

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C09D 5/24 PQW 7211-4J

Claims (1)

[Claims] 1. (a) Copper powder, (b) Thermosetting resin,
(C) a compound represented by the following general formula 1 and (D) A conductive composition having 3 or more nitrogen atoms in one molecule and containing a polyamine having a weight average molecular weight of 80 to 30,000.