Marine lubricating oil composite additive

Abstract

A marine lubricating oil composite additive is provided. Based on the total weight of the composite additive, said marine lubricating oil composite additive comprises: 25-45% sulfonate detergent with superhigh base number, 40-60% phenolate detergent with low base number, 0-8% dispersing agent, 0-4% antiwear agent, and 10-20% Group I base oil with high viscosity index which is selected from the group consisting of 400SN, 500SN and 600SN. The composite additive of the present invention can satisfy the requirement of BOB system about the viscosity and base number, and can be blended with many system oils under a number of domestic and foreign brands so as to provide cylinder lubricating oils with different base numbers. The composite additive of the present invention has good adaptability and excellent performances in terms of antiwear, antioxidization and high temperature detergency, which meet the requirement of marine engines about the performance of cylinder lubricating oils.

1 . A marine lubricating oil composite additive, wherein, based on the total weight of the composite additive, it comprises: 25-45% sulfonate detergent with superhigh base number, 40-60% phenolate detergent with low base number, 0-8% dispersing agent, 0-4% antiwear agent, and 10-20% Group I base oil with high viscosity index which is selected from the group consisting of 400SN, 500SN and 600SN;
 said sulfonate detergent with superhigh base number is C 22 -C 30  linear alkyl benzene calcium sulphonate, wherein the base number thereof is 395-430 mgKOH/g;   said phenolate detergent with low base number is C 20 -C 25  alkyl sulfurized calcium phenolate, wherein the base number thereof is 240-265 mgKOH/g;   said dispersing agent is selected from the group consisting of mono-polyisobutylene succinimide, bis-polyisobutylene succinimide and multi-polyisobutylene succinimide;   said antiwear agent is zinc long-chain alkyl thiophosphate with the structure corresponding to the following formula,   
       
         
           
           
               
               
           
         
         wherein R 1 , R 2 , R 3  and R 4  are long-chain primary alkyl groups each comprising 12-18 carbon atoms, or R 1 , R 2 , R 3  and R 4  are long-chain secondary alkyl groups each comprising 12-16 carbon atoms. 
       
     
     
         2 . The marine lubricating oil composite additive according to  claim 1 , wherein the kinematic viscosity of said base oil is 8.5-11.5 cst at 100° C.