US2013137616A1PendingUtilityA1

Low phosphorus lubricating oil composition having lead corrosion control

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Individually held — no corporate assignee on recordPriority: Aug 9, 2006Filed: Jan 22, 2013Published: May 30, 2013
Est. expiryAug 9, 2026(~0 yrs left)· nominal 20-yr term from priority
Inventors:Alexander B. Boffa
C10M 2215/064C10N 2030/12C10N 2040/25C10N 2030/42C10M 2207/026C10N 2010/04C10M 2219/044C10M 2223/045C10M 2215/28C10N 2030/45C10N 2030/43C10N 2020/04C10M 169/04C10M 2207/028C10M 137/10
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Claims

Abstract

The present invention provides a low phosphorus lubricating oil composition containing a mixture of zinc dithiophosphates in a certain ratio surprisingly yields improved lead corrosion. The synergistic combination of mixed zinc dithiophosphates containing a zinc primary dialkyl dithiophosphate, zinc secondary dialkyl dithiophosphate and zinc diaryl dithiophosphate in a respective ratio, based on the phosphorus content, of the zinc primary dialkyl dithiphosphate to zinc secondary dialkyl dithiophosphate from about 2:1 to about 1:2 and the ratio of the mixture of zinc primary dialkyl dithiophosphate and zinc secondary dialkyl dithiophosphate to zinc diaryl dithiophosphate from about 6:1 to about 1:1. When used in a lubricating oil composition having a total phosphorus content less than about 0.06 wt %, based on the total weight of the lubricating oil composition to lubricate internal combustion engines. The mixture of zinc dithiophosphates greatly reduces lead corrosion.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A lubricating oil composition comprising a major amount of base oil of lubricating viscosity and a minor amount of a mixture of a zinc primary dialkyl dithiophosphate a zinc secondary dialkyl dithiophosphate and a zinc diaryl dithiophosphate wherein the respective ratio, based on the phosphorus content, of the zinc primary dialkyl dithiophosphate to zinc secondary dialkyl dithiophosphate is from about 2:1 to about 1:2 and the ratio of the mixture of zinc primary dialkyl dithiophosphate and zinc secondary dialkyl dithiophosphate to zinc diaryl dithiophosphate is from about 6:1 to about 1:1 and wherein the lubricating oil composition has less than about 0.06 wt % total phosphorus content, based on the total weight of the lubricating oil composition. 
     
     
         2 . The lubricating oil composition according to  claim 1 , wherein the minor amount of the mixture of zinc primary dialkyl dithiophosphate, zinc secondary dialkyl dithiophosphate and zinc diaryl dithiophosphate is from about 0.1 wt % to about 1.5 wt %, based on the total weight of the lubricating oil compression. 
     
     
         3 . The lubricating oil composition according to  claim 1 , wherein the minor amount of the mixture of zinc primary dialkyl dithiophosphate, zinc secondary dialkyl dithiophosphate and zinc diaryl dithiophosphate is from about 0.3 wt % to about 1.2 wt % based on the total weight of the lubricating oil composition. 
     
     
         4 . The lubricating oil composition according to  claim 1 , wherein the minor amount of the mixture of zinc primary dialkyl dithiophosphate, zinc secondary dialkyl dithiophosphate and zinc diaryl dithiophosphate is from about 0.5 wt % to about 1.0 wt %, based on the total weight of the lubricating oil composition. 
     
     
         5 . The lubricating oil composition according to  claim 1 , wherein the mixture contains from about 0.05 wt % to about 1.2 wt % zinc primary dialkyl dithiophosphate, from about 0.05 wt % to about 1.2 wt % zinc secondary dialkyl dithiophosphate and from about 0.02 wt % to about 0.7 wt % zinc diaryl dithiophosphate, based on the total weight of the lubricating oil composition. 
     
     
         6 . The lubricating oil composition according to  claim 5 , wherein the mixture contains from about 0.1 wt % to about 0.7 wt % zinc primary dialkyl dithiophosphate, from about 0.1 wt % to about 0.7 wt % zinc secondary dialkyl dithiophosphate and from about 0.05 wt % to about 0.5 wt % zinc diaryl dithiophosphate, based on the total weight of the lubricating oil composition. 
     
     
         7 . The lubricating oil composition according to  claim 6 , wherein the mixture contains from about 0.2 wt % to about 0.5 wt % zinc primary dialkyl dithiophosphate, from 0.2 wt % to about 0.5 wt % zinc secondary dialkyl dithiophosphate and from about 0.1 wt % to about 0.3 wt % zinc diaryl dithiophosphate, based on the total weight of the lubricating oil composition. 
     
     
         8 . The lubricating oil composition according to  claim 1 , wherein the primary alkyl group of the zinc primary dialkyl dithiophosphate has from about C 1  to about C 13  carbon atoms. 
     
     
         9 . The lubricating oil composition according to  claim 8 , wherein the primary alkyl group of the zinc primary dialkyl dithiophosphate has from about C 3  to about C 10  carbon atoms. 
     
     
         10 . The lubricating oil composition according to  claim 9 , wherein the primary alkyl group of the zinc primary dialkyl dithiophosphate has from about C 6  to about C 8  carbon atoms. 
     
     
         11 . The lubricating oil composition according to  claim 1 , wherein the secondary alkyl group of the zinc secondary dialkyl dithiophosphate has from about C 3  to about C 13  carbon atoms. 
     
     
         12 . The lubricating oil composition according to  claim 11 , wherein the secondary alkyl group of the zinc secondary dialkyl dithiophosphate has from about C 3  to about C 8  carbon atoms. 
     
     
         13 . The lubricating oil composition according to  claim 12 , wherein the secondary alkyl group of the zinc secondary dialkyl dithiophosphate has from about C 3  to about C 6  carbon atoms. 
     
     
         14 . The lubricating oil composition according to  claim 1 , wherein the aryl. group of the zinc diaryl dithiophosphate has from about C 6  to about C 30  carbon atoms. 
     
     
         15 . The lubricating oil composition according to  claim 14 , wherein the aryl group of the zinc diaryl dithiophosphate has from about C 8  to about C 24  carbon atoms. 
     
     
         16 . The lubricating oil composition according to  claim 15  wherein the aryl group of the zinc diaryl dithiophosphate has from about C 6  to about C 20  carbon atoms. 
     
     
         17 . The lubricating oil composition according to  claim 1 , wherein the respective ratio of zinc primary dithiophosphate to zinc secondary dialkyl dithiophosphate is a range from about 3:2 to about 2:3, based on the phosphorus content. 
     
     
         18 . The lubricating oil composition according to  claim 17 , wherein the respective ratio of zinc primary dithiophosphate to secondary dialkyl dithiophosphate is about 1:1, based on the phosphorus content. 
     
     
         19 . The lubricating oil composition according to  claim 1 , wherein the respective ratio of the mixture of zinc primary dialkyl dithiophosphate and zinc secondary dialkyl dithiophosphate to zinc diaryl dithiophosphate is a range from about 4:1 to about 1:1, based on the phosphorus content. 
     
     
         20 . The lubricating oil composition according to  claim 19 , wherein the respective ratio of the mixture of zinc primary dialkyl dithiophosphate and zinc secondary dialkyl dithiophosphate to zinc diaryl dithiophosphate is about 2:1 based on the phosphorus content. 
     
     
         21 . The lubricating oil composition according to  claim 1 , wherein the respective ratio of the mixture of zinc primary dialkyl dithiophosphate to zinc secondary dialkyl dithiophosphate to zinc diaryl dithiophosphate is 1:1:1, based on the phosphorus content. 
     
     
         22 . The lubricating oil composition according to  claim 1 , wherein the total phosphorus content of the lubricating oil composition in less than 0.05 wt %, based on the total weight of the lubricating oil composition. 
     
     
         23 . The lubricating oil composition according to  claim 1 , wherein the total sulfur content of the lubricating oil composition in less than 0.5 wt %, based on the total weight of the lubricating oil composition. 
     
     
         24 . The lubricating oil composition according to  claim 23 , wherein the total sulfur content of the lubricating oil composition in less than 0.2 wt %, based on the total weight of the lubricating oil composition. 
     
     
         25 . The lubricating oil composition according to  claim 1 , wherein the total sulfated ash content of the lubricating oil composition in less than 1.2 wt %, based on the total weight of the lubricating oil composition. 
     
     
         26 . The lubricating oil composition according to  claim 25 , wherein the total sulfated ash content of the lubricating oil composition in less than 1.0 wt %, based on the total weight of the lubricating oil composition. 
     
     
         27 . The lubricating oil composition according to  claim 26 , wherein the total sulfated ash content of the lubricating oil composition in less than 0.8 wt % based on the total weight of the lubricating oil composition. 
     
     
         28 . A method for improving lead corrosion, said method comprising operating an internal combustion engine with a lubricating oil composition comprising it major mount of base oil of lubricating viscosity and a minor amount of a mixture of zinc primary dialkyl dithiophosphate, zinc secondary dialkyl dithiophosphate and zinc diaryl dithiophosphate wherein the respective ratio, based on the phosphorus content, of the zinc primary dialkyl dithiophosphate to zinc secondary dialkyl dithiophosphate is from about 2:1 to about 1:2 and the ratio of the mixture of zinc primary dialkyl dithiophosphate and zinc secondary dialkyl dithiophosphate to zinc diaryl dithiophosphate is from about 6:1 to about 1:1 and wherein the lubricating oil composition has less than about 0.06 wt % total phosphorus content, based on the total weight of the lubricating oil composition.

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