Lubricating oil composition for internal combustion engines and method for producing same

Abstract

To provide a lubricating oil composition for internal combustion engines, which has excellent fluidity in a low temperature environment, while maintaining high shear stability, and which has low agitation resistance with respect to an engine, while exhibiting excellent stability of thermal oxidation resistance. A lubricating oil composition for internal combustion engines, which contains a lubricant base oil and a liquid random copolymer of ethylene and an alpha-olefin, said random copolymer being produced using a specific catalyst, and which is configured such that: the kinematic viscosity at 100 degC is 12.5 mm2 / s or more but less than 26.1 mm2 / s; and the lubricant base oil is composed of a mineral oil that has a kinematic viscosity at 100 degC of 2-10 mm2 / s, a viscosity index of 95 or more and a pour point of -10 degC or less and / or a synthetic oil that has a kinematic viscosity at 100 degC of 1-10 mm2 / s, a viscosity index of 120 or more and a pour point of -30 degC or less.

Description

technical field [0001] The present invention relates to a lubricating oil composition for an internal combustion engine and a manufacturing method thereof, especially a lubricating oil composition for a high output internal combustion engine and a manufacturing method thereof. Background technique [0002] Petroleum products generally have so-called temperature dependence of viscosity, that is, when the temperature changes, the viscosity changes greatly. For example, in lubricating oils used in automobiles and the like, it is preferable that the temperature dependence of the viscosity is small. Therefore, in lubricating oil, in order to reduce the temperature dependence of viscosity, a certain polymer soluble in the lubricating oil base can be used as a viscosity modifier (also called a viscosity index improver). In recent years, OCP (olefin copolymer) has been widely used as such a viscosity modifier, and various improvements as exemplified in Patent Document 1 have been m...

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Problems solved by technology

Therefore, a viscosity modifier with a relatively low molecular weight is used, but although the decrease in viscosity caused by shearing is suppressed, the temperature dependence of the viscosity is large due to the poor ability to increase the viscosity index. ℃) lubricating oil has poor fluidity, and the stirring resistance at the start of the internal combustion engine is extremely large compared with the engine oil for ordinary cars, which has a negative impact on the fuel efficiency of the internal combustion engine

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