Non-aromatic based antioxidants for lubricants
A lubricant composition comprises a cycloaliphatic amine alkoxylate and a base oil selected from (a) a polyalkylene glycol; (b) a polyalphaolefin; (c) a naphthenic compound; and (d) combinations thereof; provided that the cycloaliphatic amine alkoxylate and the base oil are miscible. The lubricant may exhibit a viscosity change at 40° C. of less than 5 percent (%) after 13 days at 120° C. in dry air, indicating significant thermoxidative stability with minimal or no aromatic content, thereby enabling use of Groups II and III base oils, in particular, without reduced toxicity and/or quality concerns as compared with Group I base oil lubricants.
1. A lubricant composition comprising a cycloaliphatic amine alkoxylate and a base oil selected from (a) a polyalkylene glycol; (b) a polyalphaolefin; (c) a naphthenic compound; and (d) combinations thereof; provided that the cycloaliphatic amine alkoxylate and the base oil are miscible,
and wherein the cycloaliphatic amine alkoxylate is selected from the group consisting of 1,2-cyclohexane diamine propoxylate having a propylene oxide content from 5 to 10 moles per mole of 1,2-cyclohexane diamine; 1,2-cyclohexane diamine butoxylate having a butylene oxide content from 5 to 10 moles per mole of 1.2-cyclohexane diamine; and combinations thereof.
2. The lubricant composition of claim 1 wherein the lubricant composition exhibits a viscosity change of less than 5 percent (%) after 13 days at 120° C. in dry air, according to viscosity testing carried out at 40° C. under ASTM D7042.
3. The lubricant composition of claim 1 wherein the base oil is a Group II, or III base oil, as categorized according to the American Petroleum Institute.
4. The lubricant composition of claim 1 wherein the cycloaliphatic amine alkoxylate is present in an amount ranging from 100 parts per million to 5 weight percent.
5. A method of making a lubricant composition comprising combining at least a cycloaliphatic amine alkoxylate and a base oil selected from (a) a polyalkylene glycol; (b) a polyalphaolefin; (c) a naphthenic compound; and (d) combinations thereof; under conditions such that the cycloaliphatic amine alkoxylate and the base oil are miscible, wherein the cycloaliphatic amine alkoxylate is selected from the group consisting of 1,2-cyclohexane diamine propoxvlate having a propylene oxide content from 5 to 10 moles per mole of 1,2-cyclohexane diamine; 1,2-cyclohexane diamine butoxylate having a butylene oxide content from 5 to 10 moles per mole of 1,2-cyclohexane diamine; and combinations thereof.
6. The method of claim 5 wherein the cycloaliphatic amine alkoxylate is prepared by reacting the amine initiator with an alkoxide selected from propylene oxide, butylene oxide, and combinations thereof; under conditions suitable to form a cycloaliphatic amine alkoxylate.
7. The method of claim 5 wherein the cycloaliphatic amine alkoxylate is present in the lubricant composition in an amount ranging from 100 parts per million to 5 weight percent.
8. The method of claim 5 wherein the cycloaliphatic amine alkoxylate is present in the lubricant composition in an amount ranging from 1 weight percent to 5 weight percent.