METHOD FOR IMPROVING THERMAL-OXIDATIVE STABILITY AND ELASTOMER COMPATIBILITY

摘要

A method for improving thermo-oxidative stability and elastomer compatibility in an apparatus lubricated with a lubricating oil by using as the lubricating oil a formulated oil including a lubricating oil base stock. The lubricating oil base stock includes a di-alkylated aromatic base stock of the formula:;(R1)—(R2)—(R1);wherein each R1 is the same or different and represents a C10-C30 alkyl group; R2 represents an aromatic moiety. The di-alkylated aromatic base stock includes at least 44 wt % dialkylate product. Thermo-oxidative stability and elastomer compatibility are improved as compared to thermo-oxidative stability and elastomer compatibility achieved using a lubricating oil base stock other than the di-alkylated aromatic base stock. A lubricating oil including the di-alkylated base stock of the above formula, and the di-alkylated aromatic base stock of the above formula.

主权项

1. A method for improving thermo-oxidative stability and elastomer compatibility in an apparatus lubricated with a lubricating oil by using as the lubricating oil a formulated oil comprising a lubricating oil base stock; wherein the lubricating oil base stock comprises a di-alkylated aromatic base stock of the formula:
(R1)—(R2)—(R1) wherein each R1 is the same or different and represents a C10-C30 alkyl group; R2 represents an aromatic moiety; wherein branching characteristics of the alkyl groups have a total methyl number (“TMN”) determined by C13 NMR spectroscopy of from 1.0 to 2.1 or have a branching index (“BI”) of from −1.0 to 0.1, wherein TMN is calculated by dividing the sum of integrated areas for all methyl groups by the total integration area for all aliphatic carbons and multiplying the result by the averaged chain length carbon number, and wherein BI is TMN minus 2 (two terminal methyl carbons); wherein the di-alkylated aromatic base stock comprises at least 44 wt % dialkylate product; and wherein thermo-oxidative stability and elastomer compatibility are improved as compared to thermo-oxidative stability and elastomer compatibility achieved using a lubricating oil base stock other than the di-alkylated aromatic base stock.