JPH0380198B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to polyphenyl ether lubricants with improved wettability to contact materials.

BACKGROUND OF THE INVENTION Electrical contacts, particularly those for sliding connectors, tend to be lubricated to reduce mating forces, reduce wear, or seal pinholes.
This is said to be particularly effective when the contacts are plated with a base metal, such as tin.

Prior Art and Problems Conventionally, paraffin has often been used as a lubricant for contacts. However, paraffin is a solid and gradually disappears from the contact portion as the contact slides repeatedly. On the other hand, a liquid lubricant with fluidity has the advantage that even if the film breaks during contact sliding, it can be repaired immediately due to its fluidity. Such a liquid lubricant cannot be used with high reliability unless it has good wetting properties to the contact metal when applied to the contact. Surfactants that improve the wettability of lubricants to contact metals are selectively effective.

OBJECTS OF THE INVENTION An object of the present invention is to selectively identify a liquid lubricant that is effective when applied to contacts and a surfactant that is added thereto.

Structure of the Invention The above object of the present invention is to produce a copolymer of perfluoroalkylene and acrylic ester, or a phosphoric acid monoester, a phosphoric diester, and a trace amount of a copolymer of a perfluoroalkylene and an acrylic ester, or a phosphoric acid monoester or phosphoric diester having a benzene ring in the lipophilic group, which is based on polyphenyl ether. This can be achieved by a contact lubricant characterized in that 0.5% by weight or more of a mixture of phosphoric acid triesters is added to the base.

In general, liquid lubricants require a reduction in the coefficient of friction, stabilization of contact resistance, as well as heat and oxidation resistance when applied to contacts, and polyphenyl ethers (e.g., Monsanto OS-124) I found it to be very good overall. However, there is a drawback that the contact plating film does not have sufficient wettability, especially for tin, tin-lead alloy, or gold.

A copolymer of perfluoroalkylene and acrylic ester, or a phosphoric acid monoester or phosphoric acid diester having a benzene ring in the lipophilic group can be used as a surfactant to selectively improve the wettability of polyphenyl ether. We have found that a mixture consisting of phosphoric acid triester and trace amounts of phosphoric acid triester is suitable. Some of such phosphate ester type surfactants are represented by the following general formula.

Phosphoric acid monoester phosphoric acid diester Here, R represents an alkylphenyl group having 8 to 30 carbon atoms.

If the amount of the fluorine surfactant and phosphate ester surfactant used is less than 0.5% by weight, there will be no effect.

Commercially available products include 3M's product name FC-430 or FC-431, which contains a copolymer of perfluoroalkylene and acrylic ester, as well as phosphoric acid monoester, phosphoric diester, and phosphoric acid diester having a benzene ring in the lipophilic group. Manufactured by Toho Chemical, trade name: GAFAC RE, containing a mixture consisting of trace amounts of phosphoric acid triesters.
-610 or RE-610, and the latter neutralized with triethanolamine can be used.

Example 1 For polyphenyl ether, as a fluorine-based surfactant having an ester bond, 3M Co., Ltd.
Florard FC-430 was added in an amount of 0.1 to 10% by weight to form a lubricant. The contact is made by plating a nickel film with a thickness of 2 μm on a phosphor bronze base material, and then plating a tin film with a thickness of 3 μm on top of this to form the contact pin.
The above lubricant was applied to this, a load of 150 g was applied, and the coefficient of friction was measured. As shown in FIG. 1, when the surfactant was added in an amount of 0.5% by weight or more, the variation in the coefficient of friction was reduced, and the lubricant acted effectively.

Example 2 A contact was applied in the same manner as in Example 1, except that Florard FC-431, which is similar to 3M's Florard FC-430, was used as a fluorosurfactant having an ester bond. Measure the coefficient of friction,
Similar results as in Example 1 were obtained.

Example 3 As a surfactant, a phosphate ester type having a benzene ring in the lipophilic group manufactured by Toho Chemical Co., Ltd., trade name
Figure 2 shows the results of applying GAFAC RE-610 to the contacts and measuring the friction coefficient in the same manner as in Example 1 except that GAFAC RE-610 was used. In this case as well, when the surfactant was added in an amount of 0.5% by weight or more, the variation in the coefficient of friction was reduced and the lubricant acted effectively.

Example 4 The coefficient of friction was measured in the same manner as in Example 3, except that the surfactant was neutralized with triethanolamine before being added. Similar results as in Example 3 were obtained.

Effects of the Invention According to the present invention, the polyphenyl ether in which the surfactant is specified has good wettability to the contact point, and can reduce the friction coefficient of the contact point with sufficiently high reliability. Since the insertion/extraction force in a connector having contacts can be reduced, it is possible to realize a multi-pin connector for use in electronic equipment in which elements are densely mounted.

Note that the lubricant according to the present invention can be applied to other contact materials such as gold or palladium in addition to the tinned film shown in Example 1.

[Brief explanation of drawings]

Figure 1 shows the amount of fluorine-based surfactant, which is a copolymer of perfluoroalkylene and acrylic ester, added to polyphenyl ether;
It is a graph showing the relationship between the friction coefficient and the contact point coated with this lubricant. FIG. 2 is a graph showing the relationship between the amount of a phosphate ester surfactant having a benzene ring in its lipophilic group added to polyphenyl ether and the friction coefficient of a contact point coated with this lubricant.

Claims (1)

[Scope of Claims] 1 Polyphenyl ether as a base, a copolymer of perfluoroalkylene and acrylic ester, or a phosphoric acid monoester, a phosphoric diester, and a trace amount of a phosphoric acid triester having a benzene ring in the lipophilic group. A contact lubricant characterized by adding 0.5% by weight or more of a mixture consisting of esters. 2. The contact lubricant according to claim 1, which contains a phosphate ester type surfactant neutralized with triethanolamine.