JPS6147200B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a lubricating composition used for sliding contacts such as switches in electronic devices, and particularly to a lubricating composition for electrical contacts that has excellent properties for use in contacts that conduct current of several amperes. Conventional lubricants for electrical contacts have been silicone-based, mineral oil-based, and synthetic oil-based. However, silicone-based ones are 10-30V, 0.3
When used in contacts where arcs of ~5A (hereinafter referred to as "medium current") occur, SiO is generated, which causes contact failure because it is an insulator. For this reason, silicone-based lubricants cannot be used as contact lubricants for medium currents. In addition, although mineral oil-based and synthetic oil-based products do not generate SiO, they generally have unstable contact resistance, and furthermore, when subjected to a load operation life test, they may produce sludge or carbide, causing insulation failure. many. In addition, there are many materials that have an extremely detrimental effect on the constituent molding materials of the switch, such as plastics. In view of the above-mentioned circumstances, the present invention aims to solve such problems, and is an electrical contact having stable contact resistance and insulation resistance characteristics in contacts for signal switching from minute currents to medium currents. The present invention provides a lubricating composition for In other words, the invention consists of (a) general structural formula; (R is an alkyl group having 3 to 12 carbon atoms, and n is an integer of 1 to 6.) 100 parts by weight of an aliphatic hydrocarbon oil, (b) lithium hydrocarbon as a thickener; A lubricant for electrical contacts characterized by containing 0.1 to 20 parts by weight of oxystearate, (c) 0.1 to 10 parts by weight of polytrifluorochloroethylene, and (d) 0.1 to 20 parts by weight of castor oil. Regarding the composition, and (2)(a) general structural formula (R is an alkyl group having 3 to 12 carbon atoms, and n is an integer of 1 to 6.) 100 parts by weight of an aliphatic hydrocarbon oil, (b) lithium hydrocarbon as a thickener; 0.1 to 20 parts by weight of oxystearate, (c) 0.1 to 10 parts by weight of polytrifluorochloroethylene, (d) 0.1 to 20 parts by weight of castor oil, (e) 0.1 to 10 parts by weight of ricinoleic acid ester. The present invention relates to a lubricating composition for electrical contacts, comprising the following. An example of the aliphatic hydrocarbon oil (a) which constitutes the main component of the lubricating composition in the present invention is polyα-olefin oligomer. The aliphatic hydrocarbon oil preferably has a viscosity of about 4 to 20 cst at 98.9°C. If it is less than 4 cst, the lubricity will be poor and the composition will easily volatilize. Moreover, when it exceeds 20 cst, the viscous resistance increases, which adversely affects the lubricity of the contact and tends to cause contact failure. The lithium hydroxystearate (b) used in the present invention imparts viscosity to the aliphatic hydrocarbon oil as the component (a), and is also effective in stabilizing the coefficient of friction up to about 100°C. It is necessary to select lithium hydroxystearate in an amount of about 0.1 to 20 parts by weight based on 100 parts by weight of component (a). If the amount of lithium hydroxystearate is less than about 0.1 parts by weight, it will not have any effect on lubricity and will likely cause wear and insulation failure during a load operation life test, while if it exceeds about 20 parts by weight, the dispersibility of abrasive organisms will be affected. This is inappropriate as it tends to cause insulation failure. When polytrifluorochloroethylene (c) used in the present invention is used in a small amount, it is effective in stabilizing the contact resistance in the load operation life test. Polytrifluorochloroethylene is about 0.1 to 100 parts by weight of component (a).
It is necessary to select within a range of 10 parts by weight.
If the amount of polytrifluorochloroethylene is less than about 0.1 part by weight, it is not effective in stabilizing the contact resistance in the load operation life test, and if it exceeds about 10 parts by weight, the initial contact resistance becomes unstable. The castor oil (d) used in the present invention is effective in dispersing wear products during a load operating life test, and does not itself generate large amounts of char. It also has an effect on lubricity. Castor oil has 100 components of (a)
It is necessary to select within the range of about 0.1 to 20 parts by weight. If the amount of castor oil is less than about 0.1 parts by weight, it has no effect on dispersibility, and if it exceeds about 20 parts by weight, contact problems occur. The ricinoleic acid ester (e) used in the present invention is not necessarily necessary for applications with high contact pressure electrical contacts, but it is an effective component for low contact pressure electrical contacts and is essential in the second invention. It is an ingredient. In other words, it is not very effective when the contact pressure is high (30g or more per contact), but it is effective in stabilizing contact resistance and reducing sliding noise for electrical contacts with lower contact pressure. . Examples of ricinoleic acid esters include methyl ricinoleate and ethyl ricinoleate. In order to obtain the effect of stabilizing contact resistance when used for low contact pressure, it is generally necessary to use the component (a) in an amount of about 0.1 to 10 parts by weight per 100 parts by weight of component (a). If it is less than 0.1 parts by weight, it will not be effective in stabilizing contact resistance, and if it exceeds 10 parts by weight, lubricity will deteriorate. When ricinoleic acid ester is used, it is very effective because less carbide is generated in the load operation life test. Ricinoleic acid ester is an aliphatic compound with a structure like CH ₃ (CH ₂ ) ₅ CH (OH) CH ₂ CH = CH (CH ₂ ) ₇ COOR (R is an alkyl group) and has a hydroxyl group (-OH) in the molecule. It is a carboxylic acid ester, and having a hydroxyl group in the molecule improves its adhesion to the metal at the contact point, and since it contains a large amount of oxygen, the amount of carbide produced is also reduced. On the other hand, the presence of an ester bond makes it more conductive than general saturated aliphatic hydrocarbons, which is advantageous for reducing the delicate contact resistance of electrical contacts. In other words, it contributes to the tunnel effect conductivity that exists at the electrical contact. The lubricating composition of the present invention is prepared by heating and mixing the above components (a) and (b), adding other components, and uniformly kneading with a three-roll mill. This may be used as is, but in addition, an antioxidant,
Rust inhibitors and alkyl mercaptans may be added. According to the present invention, a lubricating composition for electrical contacts having stable contact resistance and insulation resistance characteristics in contacts for signal switching from minute currents to medium currents was obtained. Examples will be explained below. In the example,
All parts are by weight. Example 1 (a) Poly α-olefin oligomer (viscosity 98.9°C
6cst) 100 parts (b) Lithium hydroxystearate 5 parts (c) Polytrifluorochloroethylene 5 parts (d) Castor oil 1 part Example 2 (a) Poly α-olefin oligomer (viscosity 98.9°C
6cst) 100 parts (b) Lithium hydroxystearate 5 parts (c) Polytrifluorochloroethylene 10 parts (d) Castor oil 5 parts Example 3 (a) Poly α-olefin oligomer (viscosity 98.9°C
6cst) 100 parts (b) Lithium hydroxystearate 5 parts (c) Polytrifluorochloroethylene 5 parts (d) Castor oil 1 part (e) Methyl ricinoleate 2 parts Example 4 (a) Poly α-olefin Oligomer (viscosity 98.9℃
6cst) 100 parts (b) Lithium hydroxystearate 5 parts (c) Polytrifluorochloroethylene 10 parts (d) Castor oil 5 parts (e) Methyl ricinoleate 2 parts Switch contacts using these lubricating compositions The contact resistance and insulation properties (withstanding voltage breakdown) were measured through a 30,000 load operation life test. The results are shown in Table-1, Table-2 and Table-3.
1. Table 2 uses a switch contact with a contact pressure of about 30 g, and Table 3 uses a switch contact with a contact pressure of about 10 g. The load conditions are
It performed 20 operations per minute at DC25V and 1A. Withstand voltage breakdown was measured by applying AC500V for 1 minute.

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[Table] The present invention has the above-mentioned structure, and as is clear from the table, it provides a lubricating composition for electrical contacts that has stable contact resistance characteristics and insulation characteristics and is highly reliable. can do.

Claims (1)

[Claims] 1 (a) General structural formula (However, R is an alkyl group having 3 to 12 carbon atoms, and n is an integer of 1 to 6.) 100 parts by weight of an aliphatic hydrocarbon oil represented by (b) lithium hydrocarbon as a thickener. An electrical contact lubricating composition characterized by containing 0.1 to 20 parts by weight of oxystearate, (c) 0.1 to 10 parts by weight of polytrifluorochloroethylene, and (d) 0.1 to 10 parts by weight of castor oil. thing. 2 (a) General structural formula (However, R is an alkyl group having 3 to 12 carbon atoms, and n is an integer of 1 to 6.) 100 parts by weight of an aliphatic hydrocarbon oil represented by (b) lithium hydrocarbon as a thickener. 0.1 to 20 parts by weight of oxystearate, (c) 0.1 to 10 parts by weight of polytrifluorochloroethylene, (d) 0.1 to 10 parts by weight of castor oil, (e) 0.1 to 10 parts by weight of ricinoleic acid ester, A lubricating composition for electrical contacts, comprising: