Lubricant Composition

Abstract

The present invention provide a lubricant composition comprising a lubricant base oil, wherein said lubricant composition contains 0.08% by mass or less of zinc dithiophosphate or no zinc dithiophosphate as phosphorus amount for total amount of said lubricant composition, contacts metallic materials containing lead, and contains at least a kind of additive selected from a group consisting of following (A)˜(D): (A) organomolybdenum compounds (except molybdenum dithiophosphate); (B) borate ester and / or derivatives thereof; (C) organomolybdenum compounds, and borate ester and / or derivatives thereof; and (D) organomolybdenum compounds, and borated alkyl or alkenyl succinimide.

Description

TECHNICAL FIELD [0001] The present invention relates to a lubricant composition that enables to inhibit corrosion or corrosive wear of metallic materials containing lead, metallic materials containing copper-lead, or both of the metallic materials containing lead and metallic materials containing copper. In particular, the present invention relates to a lubricant composition that enables to inhibit corrosion or corrosive wear of the above materials even if the content of zinc dithiophosphate is small. BACKGROUND ART [0002] Slide materials for engine and so on mainly consist of ferrous-series and aluminum-series metallic materials. Among the slide materials, however, for making slide members of main bearing and connecting rod bearing such as bearing metal, not only metallic materials like aluminum, copper, and tin, but also metallic material containing lead and metallic material containing copper-lead are sometimes used. Such metallic materials containing lead have an excellent featu...

AI Technical Summary

Benefits of technology

[0030] The lubricant composition of the present invention, particularly in the case of reduction or nonuse of zinc dithiophosphate which is significantly effective for inhibiting lead corrosion or corrosive wear, can inhibit lead corrosion or corrosive wear and suitably used under a contact with metallic materials containing lead. This lubricant composition is low-sulfur, further, low-phosphorus and low-ash, and is excellent in long drain performance.

[0031] Further, the lubricant composition of the invention that limits the organomolybdenum compounds to a particular compound is excellent in anticorrosive property for both lead and copper. Accordingly, the lubricant composition obtained by adding the above particular compound can effectively inhibit corrosion or corrosive wear of metallic materials containing copper-lead or both of the metallic materials containing copper and metallic materials containing lead, at the same time.

[0032] Thus, the lubricant composition of the invention can be suitably used as a lubricant for internal combustion engine contacting metallic materials containing lead (in the aspect thereof limiting the organomolybdenum compound to a particular one, the lubricant for internal combustion engine contacting metallic materials containing lead, metallic materials containing copper, metallic materials containing lead-copper: hereinafter, these can be described as “metallic materials containing lead and the like”.), especially diesel engine oil and gas engine oil having lead-series slide materials. But also, the lubricant composition of the invention can be suitably used as a lubricant for apparatus having a lubrication system where the lubricant contacts the metallic materials containing lead and the like. The examples include: a lubricant for drive-train such as automatic transmission, manual transmission, continuously variable transmission, and gears; lubricant such as wet-type brake oil, hydraulic oil, turbine oil, compressor oil, bearing oil, and refrigerant oil.

Problems solved by technology

Such metallic materials containing lead have an excellent feature that it has little fatigue phenomena, whereas the material has a fault that the corrosive wear thereof is easily caused.

The reality of cause of corrosion is more complex, as it is controlled by many factors.

Nevertheless, it is known that when the content of zinc dithiophosphate is reduced, the corrosive-wear inhibiting effect of lead is exponentially deteriorated (e.g., Non-Patent Document 6).

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