JPH04146972A - Conductive paste composition - Google Patents

Abstract

PURPOSE:To obtain the title compsn. having a good electrical conductivity while preventing the oxidation of copper powder by compounding a synthetic resin contg. copper powder with specific compds. CONSTITUTION:The title compsn. is produced by compounding a synthetic resin (e.g. a phenol resin) contg. copper powder (pref. having a particle size of 0.1-200mum) with at least one compd. selected from the group consisting of an arom. carboxylic acid, a substd. arom. carboxylic acid, an arom. carboxylic acid having a substd. hydroxyl group, and their metal salts (e.g. a p-alkylbenzoic acid, a p-alkyloxybenzoic acid, zinc benzoate, or m-toluic acid) and at least one compd. selected from the group consisting of a basic higher aliph. amine and a nitrogenous heterocyclic compd. (e.g. triethanolamine or quinoline). The obtd. compsn. is free from the oxidation of copper powder and has a good electrical conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a conductive paste composition, and particularly to a conductive paste composition containing copper powder.

In recent years, with the development of electronic devices, the conventional method of forming conductor circuits by etching copper foil, etc. has changed to the formation of conductor circuits by screen printing using conductive paste compositions, and the use of solder to connect conductors. For example, there is a shift to adhesion using conductive paste compositions.

Further, electromagnetic waves generated in electronic devices such as computers cause radio wave interference, which has become a problem, but this problem has been solved by applying a conductive paste composition to an electromagnetic shielding material.

(Prior art) A conductive paste composition contains a conductive filler, a binder mainly composed of metal powder and a synthetic resin, and optionally a solvent.
It is a composite material consisting of additives, and the performance of the composition is determined by the properties and combination of these materials.

Conventionally, silver, copper, and nickel powders have been used as metal powders, and although silver and copper powders have excellent conductivity, silver powders are noble metals and are the most expensive. Copper powder is the most advantageous in terms of cost, but it forms a surface oxide film quickly, making it difficult to connect the original conductivity. Nickel powder has lower inherent conductivity than copper powder. Also, the price is higher than copper powder, but cheaper than silver powder.
The surface oxide film is formed at a slower rate than copper powder, making it easier to maintain conductivity.

As shown above, copper powder is very advantageous as a material for conductive compositions, both in terms of its inherent conductivity and cost, but it forms a non-conductive oxide film very quickly, and Not only is it difficult to handle, but even if a conductive composition is produced using reduced copper powder, oxidation will begin again and it will not have electrical conductivity. Various proposals have been made to solve this problem.

As a method for this, there is a method of using various additives.

Additives include higher saturated fatty acids and higher unsaturated fatty acids. For example, Japanese Patent Application Laid-open No. 58-61144,
58-74759, 58-145769, 61-211378, 62-230869, 62-252988, 63-83178
There are palmitic acid, stearic acid, oleic acid, linoleic acid, etc. described in the above publication. The reducing agents described in the above publication include aliphatic amines, aliphatic phosphate esters Bs, and metal chelating agents. These include triphenolamine, dimethylamine, stearylamine, and the like. Various methods have been proposed in which these methods are used in combination.

(Problems to be Solved by the Invention) However, no additive has been found that satisfies the oxidation of copper powder.

An object of the present invention is to provide an additive that prevents copper oxidation from a combination of additives among various additives.

(Means for Solving the Problems) As a result of various studies on these issues, the present inventors have found that 1) aromatic carboxylic acids, aromatic carboxylic acids having substituents, etc. A conductive paste composition characterized by containing a carboxylic acid, an aromatic carboxylic acid having a substituent on a hydroxyl group, and/or a metal salt thereof, and a basic higher aliphatic amine and/or a nitrogen-containing heterocyclic compound. thing.

2) As the additive of claim 1, aromatic carboxylic acids, aromatic carboxylic acids having a substituent, aromatic carboxylic acids having a substituent on the hydroxyl group, and metal salts thereof include p-alkylbenzoic acid, p-alkyl 1. An electrically conductive paste composition comprising oxybenzoic acid, zinc ammonate, m-toluic acid, o-anisic acid, diphenylacetic acid, and I-naphthoic acid.

Here, do-alkylbenzoic acid is a compound represented by formula (11), and p-alkyloxybenzoic acid is a compound represented by formula (2).

Here, R is an alkyl group of CnH2n*l, and n is I-16.

3) Examples of the basic higher aliphatic amine and the compound compound as additives in claim include triphenolamine,
N-cyclohexylgetanolamine, di-n-octylamine, alkyltrioxyethylene ammonium hydroxide, N-n-butylciethanolamine, 1.1.1”-nitrilo-2-propanol, quinoline and isoquinoline The problem was solved by a conductive paste composition characterized by the following.

The copper powder used in the present invention may be a commercially available product produced by an ordinary electrolytic method, and the shape of the powder may be dendritic, scaly, or spherical. In addition, the particle size is 0.1
A range of 200 to 200 microns is desirable, but it can be used depending on the purpose and is not limited.

The resins used in the present invention are phenol resins, melamine resins, and xylene resins. Examples of the phenol resin are the reprinted PC-1 manufactured by Mitsubishi Gas Chemical Co., Ltd. and PL 4348B manufactured by Gunei Chemical Co., Ltd., and the melamine resin is, for example, Nikaratsuku uX-708 manufactured by Sansho Chemical Co., Ltd., US
-001, and the xylene resin is, for example, Mitsubishi Gas Chemical (
It is PR-1540 manufactured by Co., Ltd.

Additives used in the present invention (hereinafter collectively referred to as additive A)
Examples of aromatic carboxylic acids, aromatic carboxylic acids having a substituent, aromatic carboxylic acids having a substituent on the hydroxyl group, and metal salts thereof include do-alkylbenzoic acid, p-alkyloxybenzoic acid, zinc benzoate, m- These are toluic acid, 0-anisic acid, diphenylacetic acid, and -safthoic acid.

Here, p-alkylbenzoic acid is a compound represented by formula (1), and p-alkyloxybenzoic acid is a compound represented by formula (2).

Here, R is an alkyl group of CnH2n+1, where n is 1 to 16.

The basic higher aliphatic amines and heterocyclic compounds (hereinafter collectively referred to as additive B) used in the present invention include triethanolamine, N-cyclohexylgetanolamine, c-n-octylamine, and alkyltrioxy Ethylene ammonium hydroxide, N-n-phytylgetanolamine, 1.1.1”-nitrilo-2-
These are propanol, quinoline and isoquinoline. The blending ratio of these copper paste compositions is 75 to 9.
The amount is 5 wt%, preferably 85 to 90 wt%, and the remainder is the binder resin and additives.

Below or above this range, the resistance value increases.

Additives are additives AO, I to IO per 100 parts by weight of copper powder.
The weight part is preferably 0.5 to 3 weight parts, and the additive is 801 parts by weight.
The amount is 5 to 10 parts by weight, preferably 1 to 5 parts by weight.

If the amount added is small, the resistance value becomes large. If the amount added is large, the effect of lowering the resistance value becomes saturated, and there is no need to add a large amount, which may lead to a decrease in coating film strength.

(Example) The present invention will be explained in detail based on examples.

Example 1 A copper vest was prepared by thoroughly dispersing these materials and passing them through a roll three times.

The following additives were tested in the above formulation. They are p-n-octylbenzoic acid, p-n-octyloxybenzoic acid, zinc benzoate, m-toluic acid, O-anisic acid, diphenylacetic acid, and -naphthoic acid.

As shown in Figure 1, a plastic plate (glass fiber-reinforced epoxy resin laminate) with copper foil pasted on it is 3cm wide.
The copper foil in the center part 4 of a copper-clad laminate with a length of 6 cm is removed by etching, and the copper foil parts 2 and 2 with a width of 1.5 cm are left on both ends of the plastic plate 1. The distance between the foil parts 2i3 and 2 is 3 cm), and as shown in Fig. 2, conductive paint is applied to the substrate A with a glass rod to a width of 1 cm to a thickness equivalent to a sheet of cellophane tape. Coating film 3 (film thickness after curing is approximately 50Lim) at 150°
C1 After curing for 15 minutes, the electrical resistance was measured with a micrometer and divided by 3 to obtain the sheet resistance value. The unit is mΩ/mouth. The results are as follows (this method is referred to as the simplified method).

Additive A alone contains benzoic acid, p-n-octyloxyamne, and 9. Fragrant acid was particularly effective.

Example 2 Triethanolamine was used as additive B, and various acids were pn-octylbenzoic acid, pn-octyloxybenzoic acid, zinc benzoate, m-toluic acid,
-Anisic acid, diphenylacetic acid, and 1-naphthoic acid were used.

The implementation method is the same as in Example 1.

The above additive A was effective when used in combination with triethanolamine (additive B).

Example 3 Various additives were tested using the following method.

As additive A, zinc benzoate, p-n-octylbenzoic acid, p-n-octyloxybenzoic acid was used, and as additive B, triethanolamine, N-cyclohexylgetanolamine, N-n- Butylciethanolamine fBDEA1.1. Tests were conducted using l',l''-nitrilo-2-propanol 1NTPl, quinoline and isoquinoline.

combination Mix 1.5g of additive B with 50g of paste.

Additives A-1 Zinc benzoate A-2 p-n-octylbenzoic acid A-3 p-n-octyloxybenzoic acid B-1 1-ethanolamine B-21,1', I"°-nitrilo-2-propanol B-3N-cyclohexylgetanolamine B-4N
-n-Butylsiethanolamine [BDEAIB-5 Quinoline B-6 Isoquinoline As an example, BO is an example showing that BO does not contain component B as an additive.

E-side conditions Tetron 180 mesh emulsion thickness 15μ was screen printed on paper-phenol (FR-2), J and Gala Evo substrates (FR-4) (Fig. 3) with the following three coating areas: (The coating thickness after curing is 1
5-20μ).

Sample size Small and medium sample size 2 x 2 cm Medium ] x 1 cm Small 0.5 x O, 5 cm Curing conditions 150°C x 15 minutes, 170°C The area resistance value (each concentrated acid) and the mold after curing at 260°C 5
Deku was determined after heat treatment for 1 minute.

The results are shown in numbers 1 to 3.

The additives of the present invention include aromatic carboxylic acids, aromatic carboxylic acids having a substituent, aromatic carboxylic acids having a substituent on the hydroxyl group, metal salts thereof, basic higher aliphatic amines, and nitrogen-containing heterocyclic compounds. There is a combined effect.

(Effects of the Invention) The additive of the present invention has good conductivity, and when used in a substrate, it is effective and can be used in various substrates.

[Brief explanation of the drawing]

FIGS. 1 and 2 are plan views of plastic plates on which a simplified test of the conductive paste of the present invention is tested. FIG. 3 is a section of the application of the conductive paste on paper phenol and glass evo substrates testing the present test of the conductive paste of the present invention. 1-...Plastic plate 3--Conductive coating 2--Engraving of copper foil drawing (no change in content) Figure 1 Procedure correction 11 February 8, 1991 Commissioner of the Patent Office 1 Description of the case 1990 Patent Application No. 269941 2 Name of the invention Conductive paste composition 3 Person making the amendment Relationship to the case Patent applicant address Tokyo 251 Suwacho, Hachioji City Name: Asahi Chemical Research Institute 4 Agent: 181 Address: 8-26-4 Kamirenjaku, Mitaka City, Tokyo δ 042
2 f47) 9240 Name +701]8+ Patent attorney Hide Kume -
5. Date of amendment order (Despatch mill) January 22, 1991 6
Target of amendment Drawing 7 Contents of amendment li' Engraving of the drawing originally attached to the application As attached (no change in content)J

Claims (1)

[Scope of Claims] 1) A conductive paste composition consisting of copper powder and a synthetic resin, which contains as additives an aromatic carboxylic acid, an aromatic carboxylic acid having a substituent, an aromatic carboxylic acid having a substituent on a hydroxyl group, and/or Or a conductive paste composition characterized by containing these metal salts and a basic higher aliphatic amine and/or a nitrogen-containing heterocyclic compound. 2) As the additive of claim 1, the aromatic carboxylic acid, the aromatic carboxylic acid having a substituent, the aromatic carboxylic acid having a substituent on the hydroxyl group, and their metal salts include p-
A conductive paste composition comprising alkylbenzoic acid, p-alkyloxybenzoic acid, zinc benzoate, m-toluic acid, o-anisic acid, diphenylacetic acid, and 1-naphthoic acid. 3) The basic higher aliphatic amine and nitrogen-containing heterocyclic compound as the additive in claim 1 include triethanolamine, N-cyclohexyldiethanolamine, di-n-octylamine, alkyltrioxyethylene ammonium hydroxide, N - An electrically conductive paste composition characterized by comprising n-butylsiethanolamine, 1,1',1''-nitrilo-2-propanol, quinoline and isoquinoline.