Lubricant composition

Abstract

A lubricating oil composition containing a base oil (A), a molybdenum-based friction modifier (B), a metal-based detergent (C), and a dispersant (D), in which the dispersant (D) contains a non-boron-modified polyisobutenyl succinic bisimide (D1). The IR spectrum of the non-boron-modified polyisobutenyl succinic bisimide (D1) is determined by an FT-IR method, having a ratio [Abs (1705 cm −1 )/Abs (1390 cm −1 )] of a peak intensity Abs (1705 cm −1 ) at 1705 cm −1 to a peak intensity Abs (1390 cm −1 ) at 1390 cm −1 is 7.5 or less. A content of the non-boron-modified polyisobutenyl succinic bisimide (D1) is 50 mass % or more based on a total amount of the dispersant (D), and contains a kinematic viscosity at 100° C. is 9.3 mm 2 /s or less. The lubricating oil composition has an excellent effect of reducing a friction coefficient while containing a molybdenum-based friction modifier and a succinimide compound.

1 : A lubricating oil composition comprising:
 a base oil (A);   a molybdenum-based friction modifier (B);   a metal-based detergent (C); and   a dispersant (D),   wherein the dispersant (D) contains a non-boron-modified polyisobutenyl succinic bisimide (D1),   a ratio [Abs (1705 cm −1 )/Abs (1390 cm −1 )] of a peak intensity Abs (1705 cm −1 ) at 1705 cm −1  to a peak intensity Abs (1390 cm −1 ) at 1390 cm −1  is 7.5 or less, in an IR spectrum of the non-boron-modified polyisobutenyl succinic bisimide (D1) as determined by an FT-IR method,   a content of the non-boron-modified polyisobutenyl succinic bisimide (D1) is 50 mass % or more based on a total amount (100 mass %) of the dispersant (D), and   a kinematic viscosity at 100° C. is 9.3 mm 2 /s or less.   
     
     
         2 : The lubricating oil composition according to  claim 1 , wherein a content of a molybdenum atom derived from the molybdenum-based friction modifier (B) is 0.04 mass % or more and 0.10 mass % or less based on a total amount (100 mass %) of the lubricating oil composition. 
     
     
         3 : The lubricating oil composition according to  claim 1 , wherein a ratio [(D1)/(B)-Mo] of a content of the non-boron-modified polyisobutenyl succinic bisimide (D1) to the content of the molybdenum atom derived from the molybdenum-based friction modifier (B) is 20 or more and 80 or less in mass ratio. 
     
     
         4 : The lubricating oil composition according to  claim 1 , wherein a sulfated ash content is 0.8 mass % or less. 
     
     
         5 : The lubricating oil composition according to  claim 1 , wherein when a metal atom contained in the metal-based detergent (C) is calcium, a content of a calcium atom derived from the metal-based detergent (C) is 0.50 mass % or less based on the total amount (100 mass %) of the lubricating oil composition. 
     
     
         6 : The lubricating oil composition according to  claim 1 , wherein when the metal atom contained in the metal-based detergent (C) is magnesium, a content of a magnesium atom derived from the metal-based detergent (C) is 0.070 mass % or less based on the total amount (100 mass %) of the lubricating oil composition. 
     
     
         7 : The lubricating oil composition according to  claim 1 , wherein when the dispersant (D) contains a boron-modified succinimide (D3), a content of a boron atom derived from the boron-modified succinimide (D3) is 0.03 mass % or less based on the total amount (100 mass %) of the lubricating oil composition. 
     
     
         8 : The lubricating oil composition according to  claim 1 , wherein a content of a nitrogen atom derived from the total dispersant (D) is 0.10 mass % or less based on the total amount (100 mass %) of the lubricating oil composition. 
     
     
         9 : The lubricating oil composition according to  claim 1 , which is suitable for an internal combustion engine. 
     
     
         10 : A method for producing a lubricating oil composition, comprising:
 mixing a base oil (A), a molybdenum-based friction modifier (B), a metal-based detergent (C), and a dispersant (D),
 wherein the dispersant (D) contains a non-boron-modified polyisobutenyl succinic bisimide (D1), 
 a ratio [Abs (1705 cm −1 )/Abs (1390 cm −1 )] of a peak intensity Abs (1705 cm −1 ) at 1705 cm −1  to a peak intensity Abs (1390 cm −1 ) at 1390 cm −1  is 7.5 or less, in an IR spectrum of the non-boron-modified polyisobutenyl succinic bisimide (D1) as determined by an FT-IR method, and 
 a content of the non-boron-modified polyisobutenyl succinic bisimide (D1) is 50 mass % or more based on a total amount (100 mass %) of the dispersant (D), and a kinematic viscosity at 100° C. is 9.3 mm 2 /s or less.