Low ash or ashless two-cycle lubricating oil with reduced smoke generation

Abstract

A new low smoke two-cycle oil comprises highly reactive polyisobutylene (“HR-PIB”), a solvent additive package, and exhibits Kinematic viscosity of at least 6.5 mm 2 /s at 100° C. and JASO M342 Smoke Index of at least 85. The new two-cycle oil is manufactured from an alternative starting material, which offers an efficient alternative as compared to polyisobutylene (“PIB”), which has traditionally been included in conventional two-cycle oils.

1 . A low ash two-cycle lubricating oil composition having a kinematic viscosity of at least 6.5 mm 2 /s (cSt) at 100° C. and a JASO M342 Smoke Index of at least 85, which composition comprises: 
 (a) 15 to 35% by weight of an olefinically unsaturated polymer selected from the group consisting of polybutene, polyisobutylene or a mixture of polybutene and polyisobutylene, which has a number average molecular weight of 400 to 2200 and a terminal vinylidene content of at least 60 mol %, based on the total number of double bonds in the polymer;    (b) 20 to 30% by weight of a normally liquid hydrocarbon or mineral oil solvent, which has a viscosity of 1 to 5 cP. at 25° C.;    (c) 1 to 5% by weight of an additive package for two cycle oils; and    (d) a mineral or synthetic oil, or a mixture thereof, which has a viscosity of 4 to 15 mm 2 /s (cSt) at 100° C.    
   
   
       2 . An ashless two-cycle lubricating oil composition having a kinematic viscosity of at least 6.5 mm 2 /s (cSt) at 100° C. and a JASO M342 Smoke Index of at least 85, which composition comprises: 
 (a) 6 to 12% by weight of an olefinically unsaturated polymer selected from the group consisting of polybutene, polyisobutylene or a mixture of polybutene and polyisobutylene, which has a number average molecular weight of 400 to 2200 and a terminal vinylidene content of at least 60 mol %, based on the total number of double bonds in the polymer;    (b) 18 to 30% by weight of a normally liquid hydrocarbon or mineral oil solvent, which has a viscosity of 1 to 5 cP. at 25° C.;    (c) 14 to 25% by weight of an metal-free additive package for two cycle oils; and    (d) a mineral or synthetic oil, or a mixture thereof, which has a viscosity of 4 to 15 mm 2 /s (cSt) at 100° C.    
   
   
       3 . The composition of  claim 1  or  2  wherein the reactive polybutene has an Mn of 800 to 1500.  
   
   
       4 . The composition of  claim 1  or  2  wherein the solvent has a viscosity of 1.2 to 2 cP. at 25° C.  
   
   
       5 . The composition of  claim 1  or  2  wherein the mineral or synthetic oil or mixture thereof has a viscosity of 12 to 15 mm 2 /s (cSt) at 100° C.  
   
   
       6 . The composition of  claim 1  or  2  wherein the additive package comprises a succinimide dispersant made from a highly reactive polyisobutylene polymer.