JP2000222960A - Material for insulating resin coating electrical contact and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent contamination on a contact part due to creeping sulfide by coating a non-electrical contact part including the periphery of an electrical contact part coated with layers of one kind of Au, Ag, Pd, Rh, Ru, Pt, Ni and Sn or the alloy thereof on a conductive band material with a specified film thickness of the insulating resin. SOLUTION: A non-electrical contact part is coated with the insulating resin such as the soft and easy workable epoxy resin and the urethane resin at 5-100 μm of thickness so as to prevent cracking in a pin hole and a plate spring or the like during work. Especially, generation and growth of the creeping sulfide at positions except for the electrical contact part to be cleaned by the opening and closing operation can be prevented by a layer of Ag and Cu. High adhesive strength can be obtained by a method of coating the solvent solution of the insulating resin with a brush or a spray and for drying and curing it with the radiation of the ultraviolet rays. Manufacturing efficiency is improved by a method of coating the whole of one surface of the wide-width conductive band material with electrical plating of the layered metal at a low cost, and coating the other surface with the insulating resin, and cutting the conductive band material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for electrical contacts excellent in environmental resistance and workability, and more particularly, to the prevention of contamination of electrical contacts of electrical contact materials by sulfide creep (surface growth of sulfide corrosion). BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for an electrical contact, which is provided with an insulating resin coating excellent in processability, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Au, on a conductive strip such as a copper alloy strip,
The electrical contact material coated with a metal such as Ag, Sn, Ni or the like in a layered form has a high strength and a high conductivity that the conductive strip has,
It is a high-performance, low-cost conductive material to which good corrosion resistance such as n and Ag, solderability, and electrical connectivity are added, and has been widely used for electric contacts and leads of electric and electronic devices for a long time.

[0003]

Electrical and electronic devices are used in various environments. Particularly in a sulfurized environment, metal components constituting electrical contacts are sulfided and corroded at locations other than the contact portions.
There is a problem that the sulfide grows and contaminates the electric contact portion, and the contact function is deteriorated. This sulfide creep is particularly Ag
Or a Cu metal layer.

[0004] That is, since the electrical contact portion is cleaned by the opening and closing operation of the contact, it is unlikely to be a source of sulfide creep. However, sulfide corrosion occurs at portions other than the contact portion, and this grows and the electrical contact portion grows. Parts may be contaminated. In order to prevent contamination caused by such sulfide creep, a method of rust-proofing the contact portion and a method of increasing the degree of sealing of the switch case accommodating the contact portion have been proposed, but all have sufficient effects. Not been. SUMMARY OF THE INVENTION An object of the present invention is to provide a material for an electrical contact that prevents contamination of a contact portion caused by sulfide creep, and a method for manufacturing the same.

[0005]

According to the first aspect of the present invention,
At least a portion on the conductive strip that is to be an electrical contact portion is A
one of u, Ag, Pd, Rh, Ru, Pt, Ni, and Sn, or a material for an electric contact coated with a metal alloy in a layered form, including at least the periphery of a portion to be the electric contact portion Insulation resin is 5-100μ on non-electrical contact part
An insulating resin-coated electrical contact material characterized in that the material is coated in a film shape to a thickness of m.

According to a second aspect of the present invention, Au, Ag, Pd,
One of Rh, Ru, Pt, Ni, and Sn or an alloy of the metal is coated in a layer, and then an insulating resin is applied to a non-electric contact portion including at least a portion around the electric contact portion in an amount of 5 to 100 μm. A method for producing a material for an electrical contact coated with an insulating resin, characterized in that the material is coated in the form of a film to a thickness.

According to a third aspect of the present invention, a non-electrical contact portion including at least a periphery of a portion to be an electric contact portion on the conductive strip is coated with an insulating resin to a film thickness of 5 to 100 μm, Then, Au, A
g, Pd, Rh, Ru, Pt, Ni, one of Sn,
Alternatively, there is provided a method for producing an insulating resin-coated electrical contact material, which comprises coating a metal alloy in a layered manner.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The electrical contact material according to the present invention reduces the occurrence of sulfide creep in the vicinity of the electrical contact portion, which contaminates the electrical contact portion, at least around the portion on the conductive strip which is to be the electrical contact portion. This is prevented by coating an insulating resin on the non-electric contact portions including the above. The reason why the coating resin is limited to the insulating resin is that when a conductive resin is used, a local battery is formed between the conductive resin and the conductive strip, and the conductive strip corrodes.

The insulating resin includes a polyimide resin, an epoxy resin, a fluorine resin, a urethane resin, a silicon resin,
Vinyl resin or the like is used. The electric contact material of the present invention may be used after being pressed into a disc spring, a brush or the like. In such applications, when a hard film is used as the insulating resin, the film may be broken and the conductive strip may be exposed. For this reason, the insulating resin is preferably a soft and highly processable epoxy resin or urethane resin.

In the present invention, the reason why the coating thickness of the insulating resin is specified to be 5 to 100 μm is that if the thickness is less than 5 μm, pinholes are formed in the insulating resin film and sulfide creep cannot be sufficiently prevented. This is because the workability of the film deteriorates and the film is cracked when processed into a disc spring or the like, whereby the effect of improving the corrosion resistance cannot be sufficiently obtained, and the cost of the insulating resin increases. A particularly preferred thickness of the insulating resin film is 20 to 50 μm. For applications requiring a withstand voltage, a thickness of 20 μm or more is required.

In the present invention, the insulating resin is coated by a method of attaching an insulating resin film with an adhesive, a method of applying an insulating resin dissolved in a solvent with a brush or a spray, and curing the same by a drying oven or ultraviolet irradiation. Are used. In particular, the latter method of applying an insulating resin dissolved in a solvent, compared to the former method of applying an insulating resin film with an adhesive, has a higher adhesive strength of the insulating resin film, is easier to coat on a curved surface, and has an adhesive. Since the adhesive is not used, there is an advantage that the adhesive does not adhere to the contact surface and adversely affect the electrical contact characteristics.

In the present invention, the conductive strip has C
u, Cu alloy, Fe, Fe alloy, Al, Al alloy, Fe
A composite material in which an alloy or an Al alloy is coated with Cu or the like can be used. Phosphor bronze, brass, beryllium copper, nickel silver and the like are used for the Cu alloy, and stainless steel and 42 alloy are used for the Fe alloy.

In the present invention, Au, Ag, Pd, Rh, Ru, Pt, and the like having small contact resistance are formed on the conductive strip.
One of Ni and Sn or an alloy of the metal is coated in a layer. The metal or alloy is coated by a conventional method such as an electroplating method, an electroless plating method, a hot-dip plating method, a clad method, and a PVD method. The electroplating method is particularly advantageous in cost.

The material for electrical contact of the present invention can be prepared, for example, by applying Au, Ag, Pd, R on one entire surface of a wide conductive strip.
one of h, Ru, Pt, Ni, Sn or an alloy of the metal is coated in a layer by electroplating, and the other surface is coated with an insulating resin to a thickness of 5 to 100 μm,
After that, it can be cut into desired dimensions by a slitter or a cutting machine to efficiently produce.

There is also a method of processing a contact part such as a disc spring or a brush and then coating the insulating resin, but the method of sticking the insulating resin film with an adhesive has poor workability because it is stuck to a non-planar part. Poor adhesion may result, and the contact portion may be contaminated with the adhesive. On the other hand, the method of applying an insulating resin dissolved in a solvent by brush or spray has a problem that the resin goes around the contact portion and contaminates the contact portion. Therefore, it is better to coat the insulating resin at the stage of the wide strip and then to slit it to a predetermined size and process it into a desired contact component, so that contamination by the adhesive and wraparound of the resin are avoided, workability, It is advantageous in terms of adhesion and productivity, and is low in cost and advantageous.

[0016]

The present invention will be described below in detail with reference to examples. (Example 1) As shown in FIG.
The insulating resin 4 shown in Table 1 is applied to the entire surface (including the other surface (not shown)) of the phosphor bronze strip 1 having a width of 5 mm and a width of 200 mm and leaving a portion (central portion having a width of 5 mm) 3 on one surface thereof. Then, as shown in FIG. 1 (b), metal 2 shown in Table 1
The material for electrical contact was manufactured by electroplating in a layer to a thickness of μm. Various materials were used for the coating metal and the insulating resin. The thickness of the insulating resin film 4 was variously changed in the range of 5 to 100 μm.

(Example 2) As shown in FIG. 2A, a metal (Ni or Sn) 2 shown in Table 1 is applied to one entire surface of a phosphor bronze strip 1 having a thickness of 0.5 mm, a width of 20 mm and a length of 200 mm.
Is electroplated in a layer to a thickness of 1 μm, and then FIG.
As shown in the figure, a portion (width 5
(central part of mm) 3 is coated with an insulating resin (polyimide resin) 4 of 5 μm or 2 over the entire surface (including other surfaces not shown).
A material for electrical contact was manufactured by coating the film to a thickness of 0 μm.

Comparative Example 1 A combination of the coated metal layer and the insulating resin film shown in Table 2 (including a case where the insulating resin film was not coated) was used, except that the thickness of the insulating resin film was 3 μm or 150 μm. An electrical contact material was manufactured in the same manner as in Example 1.

Each of the electrical contact materials obtained in Examples 1 and 2 and Comparative Example 1 was subjected to a bending process with an inner radius of 10 mm with the electroplated surface facing out, and this bent material was used as a sample for sulfidation. A corrosion test was performed, and the contact resistance of the electrical contact surface of the sample before and after the sulfide corrosion test was measured. The results are shown in Tables 1 and 2. The conditions for the sulfuration test and the method for measuring the contact resistance are as follows. [Sulfurization test conditions] Atmosphere: ₃ ppm of H ₂ S, temperature × time: 40 ° C. × 48 hours. [Contact resistance measurement conditions] Probe: Pure Ag rod with R of head 5 mm, load 98 mN [10 gf], current: 10 mA.

[0020]

[Table 1]

[0021]

[Table 2]

As is clear from Tables 1 and 2,
No. 1 to 12 all had low contact resistance after the sulfurization test. This is because contamination by sulfide creep was prevented because insulating resin was coated on portions other than the electrical contact portions. Particularly, those coated with urethane resin or epoxy resin (No.3, 5) are softer and have superior bending workability, so compared with other resins with the same coating thickness (No.7,8,10). The contact resistance after the sulfide corrosion test is extremely low. In contrast, No. 13 of the comparative example did not have an insulating resin film coated, and No. 14 had a too thin insulating resin film. During the pressing process, the insulating resin film was cracked and the conductive strip was partially exposed, and in each case, the sulfuration test produced sulfide creep around the electrical contacts, contaminating the electrical contacts. Contact resistance increased.

In the above embodiment, the other surface is coated with the insulating resin film. However, the other surface may be masked and coated on only one surface according to the application.

[0024]

As described above, the electrical contact material according to the present invention is characterized in that at least a portion of the conductive strip on which the electrical contact portion is formed is coated with Sn or the like. Since the insulating resin is coated to a predetermined thickness on the non-electric contact portions including the periphery of the electrical contact portion, no sulfide creep occurs near the electrical contact portion, and therefore, the electrical contact portion due to the sulfide creep is generated. , And good contact characteristics can be stably obtained. In addition, the electrical contact material can be easily manufactured by performing a step of coating a conductive strip with a metal or an alloy and a step of coating an insulating resin. Therefore, an industrially remarkable effect is achieved.

[Brief description of the drawings]

FIGS. 1A and 1B are process explanatory views showing a first embodiment of a method for producing an electrical contact material of the present invention.

FIGS. 2A and 2B are process explanatory views showing a second embodiment of the method for producing an electrical contact material of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Phosphor bronze strip (conductive strip) 2 Coated metal 3 Location to be an electrical contact part 4 Insulating resin

Claims (3)

[Claims] At least a portion to be an electrical contact portion on a conductive strip is made of Au, Ag, Pd, Rh, Ru, Pt, and N.
One or more of i and Sn, or an electrical contact material coated with a layer of the metal alloy, wherein the insulating resin has a thickness of 5 to 100 μm at a non-electrical contact portion including at least a periphery of a portion to be the electrical contact portion. An insulating resin-coated electrical contact material characterized by being coated in a film-like thickness. 2. A method according to claim 1, wherein at least a portion of the conductive strip which is to be an electrical contact portion is Au, Ag, Pd, Rh, Ru, Pt, or N.
i, Sn, or an alloy of the metal is coated in a layer, and then an insulating resin is formed into a film having a thickness of 5 to 100 μm on a non-electric contact part including at least a periphery of a part to be the electric contact part. A method for producing a material for an electrical contact coated with an insulating resin, characterized by coating the material. 3. An insulating resin is applied to a non-electrical contact portion including at least a portion around an electric contact portion on the conductive strip.
A film having a thickness of 100 μm is coated in the form of a film, and then Au, Ag, Pd, Rh, R
A method for producing an insulating resin-coated electrical contact material, comprising coating one of u, Pt, Ni, and Sn or an alloy of the metal in a layer.