An object of the present invention is to provide a grease composition which has little influence on the environment and has good rust prevention and water resistance against salt water such as sea water. The grease composition comprises a biodegradable base oil and a rust-preventive agent comprising a calcium sulfonate complex and a sorbitan fatty acid ester, wherein a total content of biodegradable organic substances in the grease composition is 75% by mass or more, and wherein a content of the rust-preventive agent is 2.5 to 30% by mass.

An object of the present invention is to provide a grease composition which has little influence on the environment and has good rust prevention and water resistance against salt water such as sea water. The grease composition comprises a biodegradable base oil and a rust-preventive agent comprising a calcium sulfonate complex and a sorbitan fatty acid ester, wherein a total content of biodegradable organic substances in the grease composition is 75% by mass or more, and wherein a content of the rust-preventive agent is 2.5 to 30% by mass.

The instant disclosure generally relates to lubricating compositions having an oil of lubricating viscosity, a mixture of boron-containing and boron-free dispersants, an overbased magnesium-based detergent, an overbased calcium-based detergent, an ashless friction modifier, and, optionally, other performance additives. The instant lubricating compositions may improve one or more of cleanliness, TBN retention, fuel economy and low-speed preignition (“LSPI”).

The instant disclosure generally relates to lubricating compositions having an oil of lubricating viscosity, a mixture of boron-containing and boron-free dispersants, an overbased magnesium-based detergent, an overbased calcium-based detergent, an ashless friction modifier, and, optionally, other performance additives. The instant lubricating compositions may improve one or more of cleanliness, TBN retention, fuel economy and low-speed preignition (“LSPI”).

There is provided a grease composition for improving the chemical stability of the grease composition and increasing the fatigue life of a member in which the grease composition is used. The problems can be solved by a grease composition including a poly-α-olefin; a urea-based thickener; molybdenum dithiophosphate; and barium sulfonate, wherein a difference between an SP value of the urea-based thickener and an SP value of the poly-α-olefin is 3.5 or less.

There is provided a grease composition for improving the chemical stability of the grease composition and increasing the fatigue life of a member in which the grease composition is used. The problems can be solved by a grease composition including a poly-α-olefin; a urea-based thickener; molybdenum dithiophosphate; and barium sulfonate, wherein a difference between an SP value of the urea-based thickener and an SP value of the poly-α-olefin is 3.5 or less.

The invention discloses a lubricating grease with thixotropy and a preparation method thereof. The lubricating grease comprises a polyurea/high base number calcium sulfonate composite thickener, colloidally dispersed calcium carbonate solid particles in the form of calcite, a calcium borate or calcium borate composite, and a calcium soap of fatty acid having 12 to 24 carbon atoms. The above components are uniformly dispersed in an oil phase medium. The content of high base number calcium sulfonate in the lubricating grease is less than 22 wt %.

Lubricant composition comprising:

at least one base oil; and

0.1 to 30% by weight of an imidazoline compound of formula (A):

##STR00001##

defined such that:

R.sup.1 represents a linear or branched alkyl or alkenyl group comprising 1 to 16 carbon atoms, optionally substituted at the end of the chain by a group selected from among NH.sub.2, OH or SH; and

R.sup.2 represents a linear or branched alkyl or alkenyl group comprising 1 to 36 carbon atoms.

The addition of mixed thio acid amide molybdenum dithiocarbamates to lubricant compositions comprising magnesium detergents and/or overbased magnesium detergents, e.g., overbased magnesium sulfonate, provides lubricant compositions that suppress Low Speed Pre-Ignition and possess excellent low friction characteristics. Furthermore, the addition of molybdenum based friction reducing additives, e.g., mixed thio acid amide molybdenum dithiocarbamates, in combination with one or more fatty acid 2-hydroxyalkylamides, to lubricant compositions comprising magnesium detergents or overbased magnesium detergents provides lubricant compositions that suppress Low Speed Pre-ignition and possess excellent low friction characteristics.

The addition of mixed thio acid amide molybdenum dithiocarbamates to lubricant compositions comprising magnesium detergents and/or overbased magnesium detergents, e.g., overbased magnesium sulfonate, provides lubricant compositions that suppress Low Speed Pre-Ignition and possess excellent low friction characteristics. Furthermore, the addition of molybdenum based friction reducing additives, e.g., mixed thio acid amide molybdenum dithiocarbamates, in combination with one or more fatty acid 2-hydroxyalkylamides, to lubricant compositions comprising magnesium detergents or overbased magnesium detergents provides lubricant compositions that suppress Low Speed Pre-ignition and possess excellent low friction characteristics.