Lubricating Compositions

Abstract

A lubricating composition suited to use for lubricating a hydraulic system includes an oil of lubricating viscosity and a compound comprising a polyolefin-substituted bridged hydroxyaromatic compound or metal salt thereof, wherein the wherein the polyolefin is derived from a isobutylene having a number average molecular weight of 150 to 800.

What is claimed is: 
     
         1 . A lubricating composition comprising:
 an oil of lubricating viscosity;   a corrosion inhibitor selected from 2,5-bis(tert-dodecyldithio)-1,3,4-thiadiazole, tolyltriazole, or mixtures thereof;   an antioxidant selected from aminic or phenolic antioxidants, or mixtures thereof;   a dispersant;   a neutral of slightly overbased calcium sulfonate;   an anti-wear agent selected from zinc dialkyldithiophosphate, zinc dialkylphosphate, amine salt of a phosphorus acid ester, or mixtures thereof; and   a compound comprising a polyolefin-substituted bridged hydroxyaromatic compound or salt thereof, wherein the polyolefin is derived from a branched alkene having at least 4 carbon atoms and wherein the polyolefin has a number average molecular weight of 150 to 800.   
     
     
         2 . The lubricating composition of  claim 1 , wherein the branched alkene comprises isobutylene. 
     
     
         3 . The lubricating composition of  claim 1 , wherein the polyolefin includes a chain derived from at least 4, or at least 5, or up to 6, or up to 7, or up to 8, or up to 18 branched alkene units. 
     
     
         4 . The lubricating composition of  claim 1 , wherein the polyolefin has a number average molecular weight of 150 to 400. 
     
     
         5 . The lubricating composition of  claim 1 , wherein the compound is a metal salt or pnictogen salt. 
     
     
         6 . The lubricating composition of  claim 5 , wherein the metal in the salt comprises calcium. 
     
     
         7 . The lubricating composition of  claim 1 , wherein the metal is overbased. 
     
     
         8 . The lubricating composition  claim 1 , wherein the compound is bridged with a sulfide bridge. 
     
     
         9 . The lubricating composition of  claim 1 , wherein the compound is bridged with an alkylene bridge. 
     
     
         10 . The lubricating composition of  claim 1 , wherein the compound is a bridged metal phenate. 
     
     
         11 . The lubricating composition of  claim 1 , wherein the compound is free of C8 and higher unbranched alkyl chains. 
     
     
         12 . The lubricating composition of  claim 1 , wherein the compound includes a bridged phenate unit represented by the formula: 
       
         
           
           
               
               
           
         
         and salts thereof, 
         where each R1 and each R2 represents a polyolefin group; 
         X represents a bridging group; 
         Y and Z each represent a terminal group; 
         each n is at least 1; 
         m is at least 1; and 
         p is at least 1. 
       
     
     
         13 . The lubricating composition of  claim 12 , wherein the compound is not coupled with cresol. 
     
     
         14 . The lubricating composition of  claim 12 , wherein n is 1. 
     
     
         15 . The lubricating composition of  claim 12 , wherein each R1 and R2 is independently a polyolefin of 8 to 50 carbon atoms, or at least 10 carbon atoms, or at least 10 carbon atoms, or at least 12 carbon atoms, or at least 14 carbon atoms, or at least 16 carbon atoms, or at least 18 carbon atoms, or at least 20 carbon atoms, or at least 24 carbon atoms, or up to 40 carbon atoms, or up to 35 carbon atoms, or up to 30 carbon atoms. 
     
     
         16 . The lubricating composition of  claim 12 , wherein each R1 and each R2 is a polyisobutylene. 
     
     
         17 . The lubricating composition of  claim 12 , wherein each R1 is a 300-400 MW polyisobutylene. 
     
     
         18 . The lubricating composition of  claim 1 , wherein the compound has a weight-average molecular weight of 550-5600 in its unsalted form. 
     
     
         19 . The lubricating composition of  claim 1 , wherein the compound has a weight average molecular weight of up to 2800 in its unsalted form. 
     
     
         20 . The lubricating composition of  claim 1 , wherein the dispersant comprises a borated succinimide or a non-borated succinimide dispersant or a substantially nitrogen free dispersant as described herein 
     
     
         21 . The lubricating composition of  claim 1 , wherein the compound is at least 0.01 wt. % of the lubricating composition. 
     
     
         22 . The lubricating composition of  claim 20 , wherein the compound is at least 0.01 wt%, or at least 0.02 wt %, or at least 0.05 wt%, or at least 0.1 wt. %, or at least 0.5 wt. %, or at least 1 wt. %, or at least 2 wt. % of the lubricating composition. 
     
     
         23 . The lubricating composition of  claim 1 , wherein the oil of lubricating viscosity comprises at least one of an API Group I, II, III, IV, or V base oil. 
     
     
         24 . The lubricating composition of  claim 1 , wherein the oil of lubricating viscosity is at least 10 wt. % of the lubricating composition. 
     
     
         25 . The lubricating composition of  claim 24 , wherein the oil of lubricating viscosity is at least 85 wt. % of the lubricating composition. 
     
     
         26 . The lubricating composition of  claim 1 , wherein the oil of lubricating viscosity is up to 99.5 wt. % of the lubricating composition. 
     
     
         27 . A method of lubricating a hydraulic system, comprising supplying to the hydraulic system a lubricant of  claim 1 . 
     
     
         28 . The method of  claim 27 , wherein the lubricant comprises:
 0001 wt % to 0.15 wt % of a corrosion inhibitor selected from 2,5-bis(tert-dodecyldithio)-1,3,4-thiadiazole, tolyltriazole, or mixtures thereof,   an oil of lubricating viscosity,   0.02 wt % to 3 wt % of antioxidant chosen from aminic or phenolic antioxidants, or mixtures thereof,   0.005 wt % to 1.5 wt % of a dispersant ,   0.001 wt % to 1.5 wt % of a neutral or slightly overbased calcium sulphonate,   0.001 wt % to 2 wt %, or 0.01 wt % to 1 wt % of an antiwear agent chosen from zinc dialkyldithiophosphate, zinc dialkylphosphate, amine salt of a phosphorus acid ester, or mixtures thereof; and   0.001 wt % to 5 wt % of a compound comprising a polyolefin-substituted bridged hydroxyaromatic compound or salt thereof, wherein the polyolefin is derived from a branched alkene having at least 4 carbon atoms and wherein the polyolefin has a number average molecular weight of 150 to 800.   
     
     
         29 . A method of lubricating a circulating oil system, comprising supplying to the circulating oil system a lubricant of  claim 1 . 
     
     
         30 . A method of lubricating a turbine system, comprising supplying to the turbine a lubricant of  claim 1 . 
     
     
         31 . The method of  claim 30 , wherein the lubricant comprises:
 0.0001 wt % to 0.5 wt % of a corrosion inhibitor chosen from 2,5-bis(tert-dodecyldithio)-1,3,4-thiadiazole, tolyltriazole, or mixtures thereof;   an oil of lubricating viscosity;   0.01 wt % to 1.5 wt % of antioxidant chosen from aminic or phenolic antioxidants, or mixtures thereof;   0.01 wt % to 2 wt % of a dispersant,   0.001 wt % to 1.5 wt % of a neutral or slightly overbased calcium sulphonate;   0.001 to 1 wt %, or from 0.01 to 0.5 wt % of a carboxylic acid or anhydride chosen from polyisobutylene succinic acid or anhydride thereof or dodecenyl succinic acid;   0.05 wt % to 1.5 wt %, or 0.1 wt % to 1 wt % of an antiwear agent chosen from zinc dialkyldithiophosphate, zinc dialkylphosphate, amine salt of a phosphorus acid ester, or mixtures thereof;   0.01 wt % to 1.5 wt % of a compound comprising a polyolefin-substituted bridged hydroxyaromatic compound or salt thereof, wherein the polyolefin is derived from a branched alkene having at least 4 carbon atoms and wherein the polyolefin has a number average molecular weight of 150 to 800.