JPS60251285A - Surface treating agent for plating on electrical contact - Google Patents

Abstract

PURPOSE:To improve the lubricity, pore sealing property and rust preventiveness by adding prescribed percentages of perfluoropolyether, alkylmercaptane and an oil soluble surfactant contg. fluorine. CONSTITUTION:The titled treating agent contains 1 part by weight of perfluoropolyether and 0.002-0.5 part alkylmercaptane or further contains 0.1-2 parts oil soluble surfactant contg. fluorine or 0.1-2 parts ethylene oxide adduct of 2,4,7,9- tetramethyl-5-decyne-4,7-diol. The treating agent seals well pinholes in plating and has superior lubricity and rust preventiveness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment agent applied to a plating surface applied to an electrical contact such as an electrical connector contact or an electrical switch contact.

Conventionally, electrical contacts such as electrical connector contacts and electrical switch contacts are coated with silver plating, gold plating, nickel plating, tin plating, solder plating, etc. on a copper alloy base. A surface treatment agent is further applied to the plated surface for the purposes of rust prevention, sealing (sealing pinholes in plating), and lubrication.

For example, as disclosed in Figs. 1 to 3, the electrical contacts or female contacts la of an electrical connector.

The male contacts 2a are respectively connected to the female connector housing 1.
and is incorporated into the male connector housing 2, and the stain air circuit is connected or disconnected by fitting or removing the connector.

The female contact la and male contact 2& are usually made of copper alloy, which is a conductive material. For example, the female contact la may be made of springy thin bronze or beryllium steel, and the male contact 2a may be made of brass. As mentioned above, silver plating, gold plating, nickel plating, solder plating, solder plating, etc. are applied to the surface of the base of these contacts in order to protect the base surface and reduce the contact resistance of the contacts. It is applied accordingly.

However, each contact la, 2a is
As the surface wears down due to repeated detachment operations, contact resistance increases and problems such as heat generation occur. Also,
The surface of the plating is exposed to oxidizing or sulfurizing components (e.g. H2S) in the atmosphere over time.

SO8, etc.) produces oxides or sulfides, and these products impair electrical conduction, increase contact resistance, and also increase the mating and uncoupling forces of the connector, making it inconvenient to use the connector. occurs. Furthermore, recently there has been a trend to reduce the thickness of plating on contacts in order to save resources on plating materials, and when plating is applied thinly in this way, pinholes inevitably occur. Then, the pinhole further causes corrosion of the substrate, and the corrosion causes an increase in contact resistance, an increase in fitting force, and an increase in detachment force, resulting in further problems.

In particular, recently, connectors have been miniaturized due to demands from users for the connector industry to be lighter, thinner, shorter, and smaller. There is a growing demand for connectors with weak contact pressure at the contact portions 1b and 2b of the contacts, and therefore the contact resistance tends to increase.

Therefore, conventional plating treatment alone cannot solve the problem, and there is a growing demand for applying a surface treatment agent with rust prevention, pore-sealing, and lubricity to the plating surface.

Conventionally, hydrocarbon oils such as vaseline have been used for lubricating purposes, and heterocyclic organic compounds such as benzotriazole and 2-aminobenzazole, and phosphoric acid compounds have been used for rust prevention and pore sealing purposes. It's here.

However, although these surface treatment agents were somewhat effective, they did not meet the demands of the industry.

Especially in modern connectors with low contact pressure, this increases contact resistance, making them impractical.
could not be used.

Therefore, in the connector industry, there is a need for surface treatment agents that have rust prevention, pore sealing, and lubrication properties that do not increase contact resistance even when contact pressure is low.

In view of the above circumstances, the inventors of the present invention have conducted extensive research, and as a result,
It has been found that a composition consisting of perfluoropolyether and alkyl mercaptan can significantly improve lubricity, pore-sealing properties, and rust prevention properties without increasing contact resistance even in products with low pressure bonding force.

Furthermore, an oil-soluble fluorosurfactant or 2. 4.
7. Addition of the ethylene oxide adduct of 9-tetramethyl-5-decyne-4,7-diol improves lubricity, pore-sealing, and rust prevention properties even more than the two-component composition described above without increasing contact resistance. We also found that it can be improved.

The present invention has been made based on the above findings, and the gist thereof is a surface treatment agent for plating electrical contacts containing 1 part by weight of perfluoropolyether and 5 parts by weight of alkyl mercaptan α002 to α00. It is in.

The present invention will be explained below.

The perfluoropolyether used in the present invention has the structural formula shown below, and these are used alone or in combination. The molecular weight has a range as shown by m and B.

C.F.

(ll　(OCFCF,)m +21 (ocF', cF',)n C.F.

Exposure f3) Cf 0CFCFt )m 40FxCFt
)nOF.

■ f41 [:(OCF CF t +m (OCF *
) n] However, 5≦m≦100.5≦n≦200 In addition, alkyl mercaptan has a carbon number of C, H1, SH to C
A linear or branched thiol represented by rs Hs t S H may be used alone or in combination.

The oil-soluble fluorosurfactant is Rf 802NH (CH2-0) nH RfO (CH
*CHto ) nH (However, Rf :QF+s ~
CllF21% 5≦Lotus≦200), and these are used alone or in combination.

2, 4. 7. 9-tetramethyl-5-decyne-4
゜The ethylene oxide adduct of 7-diol is, however,
It is a compound represented by (X0Y)=3 to 30, and there are various grades depending on the number of moles of ethylene oxide added. These are Air Products' Cisurfinol 44o.

These are sold under the trade names of Surf-Inol 465 and Surf-Inol 485, and in the present invention, these are used alone or in combination.

The mixing ratio of each of the above drugs is perfluoropolyether 1
Alkyl mercaptan 0.002 to [1
5 parts by weight.

If it is necessary to further improve the performance, use 0002 to 5 parts by weight of alkyl mercaptan and 0.1 to 0.1 to 5 parts by weight of an oil-soluble fluorosurfactant per 1 part by weight of perfluoropolyether.
2.0 parts by weight or 2. 4. 7゜9-Tetramethyl-
0.1 to 2.0 parts by weight of the ethylene oxide adduct of 5-decyne-4,7-diol is suitable.

Alkyl mercaptan for perfluoropolyether and oil-soluble fluorosurfactant or 2. 4.
7. If the amount of ethylene oxide adduct of 9-tetramethyl-5-decyne-4,7-diol is more than the above value, the contact resistance value will increase and it will not be practical.If it is less than the above value, the lubrication, Rust prevention and pore sealing effects decrease.

In order to attach the above drug components to the connector, they may be dissolved in a suitable organic solvent at a predetermined weight ratio, the contact parts 1b and 2b of the contact may be immersed in this solution, and then air-dried at room temperature.

The organic solvent is not particularly limited as long as it dissolves the effective two or three components, but from the viewpoint of handling safety, nonflammability, volatility, etc., Freon 113 (CCeF,
-CC6*F) is preferred.

The concentration of the solvent is best within the range of 1 to 5% by weight based on the concentration of perfluoropolyether. If the concentration is higher than 5%, it is not only uneconomical, but also makes the coated contact surface sticky and difficult to handle. If the concentration is lower than 1%, sufficient lubrication, rust prevention, and sealing effects cannot be obtained. .

Next, the present invention will be explained in more detail by showing Examples and Comparative Examples.

Examples and Comparative Examples The contact parts 1b and 2b of male and female contacts of the same shape, which were plated with gold or silver, were immersed in a solution containing various surface treatment agents in a predetermined weight ratio and concentration for 30 seconds, and then air-dried at room temperature. I did the test below.

(1) Contact Resistance Male and female contacts were bonded together, and the electrical resistance of the bonded portion was measured using a resistance meter.

(2) Fitting and disconnection test The female contact was fixed, and the male contact was repeatedly engaged and disconnected from the female contact. After repeating 1000 times, the fitting force was measured using a load-displacement tester.

(3) Rust prevention and pore sealing test Leave the terminal coated with the surface treatment agent outdoors in a place out of direct sunlight for 6 months for silver plating and 12 months for gold plating, and then check the degree of discoloration with the naked eye. Observed. rust prevention,
The ranking of the sealing effect was shown as follows.

The results of the no discoloration, slight discoloration, mild discoloration, moderate discoloration, and extreme discoloration tests are shown in Tables 1 and 2.

As is clear from the results, it can be seen that the composition according to the present invention is significantly superior overall.

Although the above embodiments have been described with respect to contacts of electrical connectors, it goes without saying that the present invention is also effective for all operating electrical contacts, such as contacts of electrical switches, contacts of relays, and contacts of tuners.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are perspective views of male and female connectors, respectively, FIG. 2(a) is a sectional view taken along the line I-I in FIG. 1(a),
Figure 2(b) is a sectional view taken along the nm arrow in Figure 1(b), and
The figure is a side view showing a fitted state of male and female contacts. 1...Female connector, 1a...Female contact, 1b...Contact part (silver or gold plated part), 2...
...Male connector, 2a...Male contact,
2b...Contact part (silver or gold plated part). Applicant Showa Denko Co., Ltd. Tama Metal Chemistry Laboratory Continuation of page 1 [Phase] Int, C1,' Identification code Internal reference number 50
:08 8217-4H Procedural amendment (discharge) r>O,O,”'5 Showa year, month, day 2, title of invention, surface treatment agent for plating of electrical contacts 3, relationship with the case of the person making the amendment Patent applicant (200) Showa Denko Co., Ltd. (and 2 others) 4, Agent 2-1-5-7 Yaesu, Chuo-ku, Tokyo, Content type of amendment Page 11 of the printed specification (Table 1), and
We will submit 2 pages (Table 2) (no changes in content) as attached. 471-

Claims (2)

[Claims] (1) A surface treatment agent for plating electrical contacts, which contains 0.002 to 0.5 parts by weight of alkyl mercaptan per 1 part by weight of perfluoropolyether. (2) Contains 2 to 5 parts by weight of alkyl mercaptan O, OO per 1 part by weight of perfluoropolyether, and further contains 1 to 2.0 parts by weight of oil-soluble fluorosurfactant α or 2.0 parts by weight to 1 part by weight of perfluoropolyether. 4. 7. 9-tetramethyl-5-decyne-4
,7-diol ethylene oxide adduct 0.1-2
．． The surface treatment agent for plating electrical contacts according to claim 1, characterized in that it contains 0 parts by weight.