JP2963517B2 - Conductive paste composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a conductive paste composition, and more particularly to a conductive paste composition containing copper powder.

In recent years, with the development of electronic equipment, conductor circuits that were conventionally formed by etching copper foil etc. have been replaced by screen printing using a conductive paste composition to form conductor circuits, and solder for connecting conductors together. The attachment has shifted to adhesion by the conductive paste composition.

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

(Conventional technology) A conductive paste composition is a composite material comprising a conductive filler, a binder mainly composed of a metal powder and a synthetic resin, and, if necessary, a solvent and an additive. Is determined by the characteristics and combination of

Conventionally, silver, copper, and nickel powders have been used as metal powders. Silver and copper powders are superior in terms of conductivity, but silver powders are noble metals and are the most expensive. Although copper powder is most advantageous in terms of cost, the speed of forming a surface oxide film is high, and it is difficult to connect the original conductivity. Nickel powder has lower intrinsic conductivity than copper powder. Also,
Although the price is generally higher than that of copper powder, it is cheaper than silver powder, the generation rate of a surface oxide film is slower than that of copper powder, and conductivity is easily maintained.

As described above, copper powder is very advantageous as a conductive composition material in terms of its original conductivity and cost, but the formation of a non-conductive oxide film is very fast, Not only is it difficult to handle, but also if a conductive composition is produced temporarily using reduced copper powder, oxidation will begin again as it is, and it will not have electrical conductivity. Various proposals have been made to solve this.

As a method therefor, there is a method using various additives.

Additives include higher saturated fatty acids and higher unsaturated fatty acids. For example, JP-A-58-61144, 58-747
No. 59, No. 58-1445769, No. 61-211378, No. 62-
No. 230869, No. 62-252988, No. 63-83178, panmitic acid, stearic acid, oleic acid,
Linoleic acid and the like. The reducing agents described in the above publications include aliphatic amines and aliphatic phosphates, and metal chelators. And they include triethanolamine, dimethylamine, stearylamine and the like. Various methods for using these in combination have been proposed.

(Problems to be Solved by the Invention) However, no satisfactory additive for preventing oxidation of copper powder was found.

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

(Means for Solving the Problems) The present inventors have conducted various studies on this, and 1) zinc benzoate or pn-alkyloxy as an additive in a conductive paste composition composed of copper powder and a synthetic resin. A conductive paste composition comprising benzoic acid. 2 ) An aromatic carboxylic acid, an aromatic carboxylic acid having an alkyl group, an aromatic carboxylic acid having an alkoxyl group, and / or a metal salt thereof, as an additive in a conductive paste composition comprising a copper powder and a synthetic resin. A conductive paste composition comprising an aliphatic amine and / or a nitrogen-containing heterocyclic compound. 3 ) An aromatic carboxylic acid, an aromatic carboxylic acid having an alkyl group, an aromatic carboxylic acid having an alkoxyl group, and a metal salt thereof as an additive of claim 2
-A conductive paste composition comprising: alkyl benzoic acid, p-alkyloxybenzoic acid, zinc benzoate, m-toluic acid, o-anisic acid, diphenylacetic acid, and 1-naphthoic acid. 4 ) The basic aliphatic amine and the nitrogen-containing heterocyclic compound as additives in claim 2 include triethanolamine, N-cyclohexyldiethanolamine, and di-n-
A conductive paste composition comprising octylamine, alkyltrioxyethylene ammonium hydroxide, Nn-butyldiethanolamine, 1,1 ', 1 "-nitrilo-2-propanol, quinoline and isoquinoline.

Solved by.

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 a C _n H _{2n + 1} alkyl group, wherein n is 1 to 1
6 things.

3) The basic aliphatic amine as the additive of claim 1 and triethanolamine, N-
Cyclohexyldiethanolamine, di-n-octylamine, alkyltrioxyethyleneammonium hydroxide, Nn-butyldiethanolamine,
The problem has been solved by a conductive paste composition characterized in that it is 1,1 ', 1 "-nitrilo-2-propanol, quinoline and isoquinoline.

As the copper powder used in the present invention, a commercially available product manufactured by an ordinary electrolytic method is sufficient, and the shape of the powder can be any of a dendritic, scaly, or spherical shape. The particle size is desirably 0.1 to 200 microns, but can be properly used depending on the application and is not limited.

The resins used in the present invention are phenol resins, melamine resins, and xylene resins. Phenol resin, for example,
Commercially available PC-1 manufactured by Mitsubishi Gas Chemical Co., Ltd., PL4348B manufactured by Gunei Chemical Co., Ltd., and the melamine resin is, for example, Nikalac MX-708, MS-001 manufactured by Sanwa Chemical Co., Ltd., and xylene resin. Is, for example, PR-1540 manufactured by Mitsubishi Gas Chemical Co., Ltd.

Examples of the additives (hereinafter, collectively referred to as additive A) used in the present invention include aromatic carboxylic acids, aromatic carboxylic acids having a substituent, aromatic carboxylic acids having a substituent on a hydroxyl group, and metal salts thereof. p-alkylbenzoic acid,
p-alkyloxybenzoic acid, zinc benzoate, m-toluic acid, o-anisic acid, diphenylacetic acid, and 1-naphthoic 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 a C _n H _{2n + 1} alkyl group, wherein n is 1 to 1
6 things.

Examples of the basic aliphatic amine and heterocyclic compound (hereinafter referred to as additive B) used in the present invention include triethanolamine, N-cyclohexyldiethanolamine, di-n-octylamine, and alkyltrioxyethylene ammonium hydroxide. , Nn-butyldiethanolamine, 1,1 ', 1 "-nitrilo-2-propanol *, quinoline and isoquinoline. The mixing ratio of these copper paste compositions is as follows: The content is 85 to 90% by weight, and the balance is a resin serving as a binder and additives.

The resistance value is increased below or above this range. Additive A is 0.1 to 10 parts by weight, preferably 0.5 to 3 parts by weight, and additive B is 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of copper powder.

If the addition amount is small, the resistance value increases. If the amount of addition is large, the effect of lowering the resistance value saturates, and it is not necessary to add a large amount, and in some cases, the strength of the coating film is reduced.

(Examples) The present invention will be described in detail based on examples.

These were well dispersed and then passed through a roll three times to prepare a copper paste.

The following additives were tested with the above formulation. pn-octylbenzoic acid, pn-octyloxybenzoic acid, zinc benzoate, m-toluic acid, o-anisic acid, diphenylacetic acid, and 1-naphthoic acid.

As shown in FIG. 1, the copper foil in the central part 4 of a copper-clad laminate of 3 cm wide and 6 cm long in which a copper foil is adhered to a plastic plate (glass fiber reinforced epoxy resin laminate) is removed by etching. A board A (having a distance of 3 cm between the copper foil sections 2 and 2 of the board A) was prepared by leaving the copper foil sections 2 and 2 having a width of 1.5 cm at both ends of the board 1 as shown in FIG. A conductive paint is applied to the substrate A with a thickness of one sheet of cellophane tape to a width of 1 cm using a glass rod, and the obtained coating film 3 (approximately 50 μm in thickness after curing) is cured at 150 ° C. for 15 minutes. The electric resistance was measured with a micrometer, and it was divided by 3 to obtain the sheet resistance. The unit is mΩ / □. The results are as follows.

With additive A alone, zinc benzoate and pn-octyloxybenzoic acid were particularly effective.

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

The conductive paste of the present invention was prepared by adding the additive B at a constant rate of 1.5 g to 50 g of the paste containing the additive A prepared in the same manner as in Example 1. The results of evaluating the conductivity in the same manner as in Example 1 are shown in the following table.

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

Example 3 Various additives were tested in the following manner.

As the additive A, zinc benzoate, pn-octylbenzoic acid, pn-octyloxybenzoic acid was used, and as the additive B, triethanolamine, N-cyclohexyldiethanolamine, Nn-butyldiethanolamine (BDEA) was used. ), 1,1 ', 1 "-nitrilo-2-propanol (NTP), quinoline and isoquinoline.

Add 1.5 g of additive B to 50 g of paste A.

Additive A-1 Zinc benzoate A-2 pn-octylbenzoic acid A-3 pn-octyloxybenzoic acid B-1 Triethanolamine B-2 1,1 ', 1 "-Nitrilo-2- Propanol B-3 N-cyclohexyldiethanolamine B-4 Nn-butyldiethanolamine (BDEA) B-5 Quinoline B-6 Isoquinoline As an example In addition, BO is an example showing that it does not contain the component B as an additive.

Printing conditions Tetron 180 mesh dairy material thickness 15μ Screen printing (Film thickness after curing is 15-20μ) Sample Large medium medium sample Large 2 × 2cm Medium 1 × 1cm Small 0.5 × 0.5cm Curing condition 150 ° C × 15 Minutes, 170 ° C x 15 minutes Items to be confirmed Heating the initial area resistance value and the sheet resistance value after boiling the cured coating film for another 60 minutes (after boiling) and the data of heat treatment at 260 ° C for 5 minutes after curing Asked later.

 The results are shown in Nos. 1 to 3.

As an additive of the present invention, an aromatic carboxylic acid, an aromatic carboxylic acid having a substituent, an aromatic carboxylic acid having a substituent in a hydroxyl group and a metal salt thereof and a basic higher aliphatic amine and a nitrogen-containing heterocyclic compound, Has a combined effect.

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

[Brief description of the drawings]

1 and 2 are plan views of a plastic plate for testing a simplified test of the conductive paste of the present invention. FIG. 3 is an illustration of the application of the conductive paste on a paper phenolic and galevo substrate to test this test of the conductive paste of the present invention. 1 ... plastic plate 3 ... conductive coating 2 ... copper foil

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C09D 5/24 H01B 1/22

Claims (4)

(57) [Claims] 1. A conductive paste composition comprising a copper powder and a synthetic resin, wherein zinc benzoate or pn is used as an additive.
-A conductive paste composition comprising alkyloxybenzoic acid. 2. An electrically conductive paste composition comprising a copper powder and a synthetic resin, as an additive, an aromatic carboxylic acid, an aromatic carboxylic acid having an alkyl group, an aromatic carboxylic acid having an alkoxyl group, and / or a metal salt thereof. And a basic aliphatic amine and / or a nitrogen-containing heterocyclic compound. 3. An aromatic carboxylic acid, an aromatic carboxylic acid having an alkyl group, an aromatic carboxylic acid having an alkoxyl group and a metal salt thereof as an additive according to claim 2 include p-alkylbenzoic acid and p-alkylbenzoic acid. A conductive paste composition comprising alkyloxybenzoic acid, zinc benzoate, m-toluic acid, o-anisic acid, diphenylacetic acid, and 1-naphthoic acid. 4. The basic aliphatic amine and the nitrogen-containing heterocyclic compound as the additive according to claim 2 are triethanolamine, N-cyclohexyldiethanolamine,
A conductive paste composition comprising di-n-octylamine, alkyltrioxyethylene ammonium hydroxide, Nn-butyldiethanolamine, 1,1 ', 1 "-nitrilo-2-propanol, quinoline and isoquinoline Stuff.