Search

EP-3768808-B1 - LUBRICANT COMPOSITION

EP3768808B1EP 3768808 B1EP3768808 B1EP 3768808B1EP-3768808-B1

Inventors

  • CHASAN, DAVID ELIEZER
  • SCHOONMAKER, Jeffrey
  • FENTON, RYAN JAMES
  • HOEY, MICHAEL

Dates

Publication Date
20260506
Application Date
20190320

Claims (20)

  1. A lubricant composition comprising a base oil, one or more antioxidants selected from a group consisting of N-α-naphthyl-N-phenylamine antioxidants and diphenylamine antioxidants; and one or more sulfur-containing additives selected from the group consisting of sulfurized isobutylene and di-tert-alkyl polysulfide, wherein the sulfurized isobutylene is a mixture of sulfur compounds comprising a sulfurized isobutylene having 1 sulfur atom, sulfurized isobutylene having 2 sulfur atoms, sulfurized isobutylene having 3 sulfur atoms, sulfurized isobutylene having 4 sulfur atoms and sulfurized isobutylene having 5 sulfur atoms.
  2. The lubricant composition according to claim 1, wherein the N-α-naphthyl-N-phenylamine antioxidants plus diphenylamine antioxidants in total are present from about 0.2 wt% to about 0.8 wt%, based on the total weight of the lubricant composition.
  3. The lubricant composition according to claims 1 or 2, wherein a sulfur concentration provided by the sulfur-containing additives, in total, ranges from about 50 ppm to about 1000 ppm by weight, based on the total weight of the lubricant composition.
  4. The lubricant composition according to any of the preceding claims, wherein the N-α-naphthyl-N-phenylamine antioxidants are of formula wherein R is H, C 1 -C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, -C(O)C 1 -C 18 alkyl or -C(O)aryl and R 1 , R 2 , R 3 and R 4 are each independently H, C 1 -C 18 alkyl, C 1 -C 18 alkoxy, C 1 -C 18 alkylamino, C 1 -C 18 dialkylamino, C 1 -C 18 alkylthio, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl or C 7 -C 21 aralkyl; and wherein the diphenylamine antioxidants are of formula wherein R is H, C 1 -C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, -C(O)C 1 -C 18 alkyl or -C(O)aryl and R 1 , R 2 , R 3 and R 4 are each independently H, C 1 -C 18 alkyl, C 1 -C 18 alkoxy, C 1 -C 18 alkylamino, C 1 -C 18 dialkylamino, C 1 -C 18 alkylthio, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl or C 7 -C 21 aralkyl.
  5. The lubricant composition according to any of the preceding claims, wherein the N-α-naphthyl-N-phenylamine antioxidants are of formula wherein R 1 and R 2 are each independently H or C 1 -C 18 alkyl; and wherein the diphenylamine antioxidants are of formula wherein R 1 and R 2 are each independently H, C 1 -C 18 alkyl, C 2 -C 18 alkenyl or C 7 -C 21 aralkyl.
  6. The lubricant composition according to any of the preceding claims, wherein the N-α-naphthyl-N-phenylamine antioxidants are of formula wherein R 2 is H and R 1 is t-butyl, t-octyl or branched nonyl; and wherein the diphenylamine antioxidants are of formula wherein R 1 and R 2 are each independently H, tert-butyl, tert-octyl or branched nonyl.
  7. The lubricant composition according to any of the preceding claims, comprising at least one additional sulfur comprising additive selected from a group consisting of sulfur-containing hindered phenolic compounds, sulfur-containing rust inhibitors, sulfur-containing friction modifiers and sulfur-containing antiwear additives.
  8. The lubricant composition according to claim 7, comprising one or more sulfur-containing hindered phenolic compounds selected from a group consisting of 2,4-di-octylthiomethyl-6-tert-butylphenol, 2,4-di-octylthiomethyl-6-methylphenol, 2,4-di-octylthiomethyl-6-ethylphenol or 2,6-di-dodecylthiomethyl-4-nonylphenol, 2,2'-thiobis(6-tert-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol), 4,4'-thiobis(6-tert-butyl-3-methylphenol), 4,4'-thiobis-(6-tert-butyl-2-methylphenol), 4,4'-thiobis(3,6-di-sec-amylphenol), 4,4'-bis(2,6-dimethyl-4-hydroxyphenyl) disulfide, octadecyl 4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl 4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate, bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, isooctyl 3,5-di-tert-butyl-4-hydroxy-benzylmercaptoacetate and esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid, β-(3,5-dicyclohexyl-4-hydroxyphenyl)-propionic acid, 3,5-di-tert-butyl-4-hydroxyphenylacetic acid or β-(5-tert-butyl-4-hydroxyphenyl)-3-thiabutyric acid with thiodiethylene glycol, 3-thiaundecanol or thiapentadecanol.
  9. The lubricant composition according to claim 7 or 8, comprising one or more sulfur-containing friction modifiers selected from a group consisting of organomolybdenum dithiocarbamates, organomolybdenum dithiophosphates and organomolybdenum compounds based on dispersants and molybdenum disulfide.
  10. The lubricant composition according to any of claims 7 to 9, comprising one or more sulfur-containing antiwear additives selected from a group consisting of sulfurized olefins, sulfurized vegetable oils, dialkyldithiophosphate esters, zinc dialkyldithiophosphates, alkyl or aryl di- or tri-sulfides, derivatives of 2,5-dimercapto-1,3,4-thiadiazole, ethyl(bisisopropyloxyphosphinothioyl)-thiopropionate, triphenyl thiophosphate, tris(alkylphenyl) phosphorothioates, diphenylmonononylphenyl phosphorothioate, isobutylphenyl diphenyl phosphorothioate, a dodecylamine salt of 3-hydroxy-1,3-thiaphosphetan 3-oxide, trithiophosphoric acid 5,5,5-tris-isooctyl 2-acetate, derivatives of 2-mercaptobenzothiazole, ethoxycarbonyl 5-octyldithiocarbamate and dihydrocarbyl dithiophosphate metal salts.
  11. The lubricant composition according to any of the preceding claims, comprising one or more ti-tert-alkyl polysulfides selected from a group consisting of di-tert-butyl polysulfide, di-tert-dodecyl polysulfide and di-tert-nonyl polysulfide.
  12. The lubricant composition according to any of the preceding claims, comprising a base oil selected from a group consisting of Group II, Group III and Group IV base oils.
  13. The lubricant composition according to any of the preceding claims, comprising a base oil selected from a group consisting of polyalphaolefins.
  14. The lubricant composition according to any of the preceding claims, comprising a base oil selected from a group consisting of synthetic esters.
  15. The lubricant composition according to any of the preceding claims, wherein the base oil comprises one or more polyalphaolefins and one or more synthetic esters.
  16. The lubricant composition according to any of the preceding claims, wherein the base oil comprises one or more polyalkylene glycols.
  17. The lubricant composition according to any of the preceding claims, comprising one or more N-α-naphthyl-N-phenylamine antioxidants and one or more diphenylamine antioxidants and wherein a weight/weight ratio of N-α-naphthyl-N-phenylamine antioxidants to diphenylamine antioxidants is from about 1/9 to about 9/1.
  18. The lubricant composition according to any of the preceding claims, wherein the base oil is present from about 80 wt% to about 99.7 wt%, based on the total weight of the lubricant composition.
  19. The lubricant composition according to any of the preceding claims, wherein the composition is substantially free of zinc dialkyldithiophosphates.
  20. An additive package comprising a) one or more N-α-naphthyl-N-phenylamine antioxidants and/or b) one or more diphenylamine antioxidants; and c) one or more sulfur-containing additives selected from the group consisting of sulfurized isobutylene and di-tert-alkyl polysulfide, wherein the sulfurized isobutylene is a mixture of sulfur compounds comprising a sulfurized isobutylene having 1 sulfur atom, sulfurized isobutylene having 2 sulfur atoms, sulfurized isobutylene having 3 sulfur atoms, sulfurized isobutylene having 4 sulfur atoms and sulfurized isobutylene having 5 sulfur atoms.

Description

This disclosure relates to formulated lubricant compositions with oxidative stability and non-corrosion properties. In particular, this disclosure relates to lubricants, methods for improving oxidative stability and non-corrosion properties of lubricants employed in a turbine gearbox and/or on turbine bearings or an engine and to additive packages for use in lubricants. Background Industrial turbines are used to convert kinetic energy into power. The most common industrial turbines are steam turbines, gas turbines and hydraulic turbines. Though varying considerably in complexity, their basic designs are essentially the same across the turbine types. Accordingly, suitable lubricants can be specifically formulated for a single type of turbine, or formulated for multiple types. Turbine oils thus share certain features, such as, for example, the basic capacity to provide reliable lubrication and performance under high operating temperatures for sustained periods of time. Steam turbines are among the most efficient of heat engines. They are typically used to drive machines such as electric generators, compressors and pumps, by converting the heat of steam to velocity or kinetic energy and then to mechanical energy. Aside from the major components, such as nozzles, valves, turbine blades, exhausts, and bearings, steam turbines also typically comprise a number of auxiliary systems that insure their safe and efficient operation. One of those auxiliary systems is the lubricating oil system, which provides clean, cool lubricating oil to the steam turbine bearings at the correct pressure, temperature, and flow rate. Certain steam turbines are equipped with mechanical-hydraulic control systems wherein the lubricating oil systems also lubricate the hydraulics. The exceedingly high operating temperatures and the otherwise harsh conditions in steam turbines place certain taxing demands on the oils, requiring, for example, sufficiently unvaried viscosity throughout the operating temperatures; resistance to fire, oxidation, sludge/varnish formation, and foaming; and anticorrosion properties. Gas turbines are commonly used in the electrical power industry to drive generators, compressors and pumps by converting part of a fuel's chemical energy into useable mechanical energy. A gas turbine, like a steam turbine, comprises major components and auxiliary systems, with the latter comprising a lubricating oil system in addition to others. In a small number of gas turbines the lubricant oils are insulated from heat, but in a majority of gas turbines, bearings and other major components are exposed to high operating temperatures, and in localized areas, these temperatures can be higher than those found in typical steam turbines. The capabilities of gas turbine oils to rapidly cool the surfaces without catching fire and retaining performance under extreme heat are thus put to the test. Even in the small number of gas turbines where the lubricant oils are not heated, however, oxidative stress remains because turbines typically undergo long periods of operation without oil service. Accordingly, a suitable gas turbine oil, like a suitable steam turbine oil, should not only provide clean and cool lubrication to the components, but also be fire resistant and impervious or nearly impervious to oxidation, rusting and/or corrosion. Hydraulic turbines are typically found in hydroelectric power plants, wherein they convert the energy of falling water into mechanical work. In hydraulic turbines, the main parts requiring lubrication are the shaft bearings, the wicket gates and the inlet valves. The lubricating oil is typically not subject to high temperatures, but its capacity to separate water from oil takes on added importance because of the ever presence of water in the operating environment. Accordingly, a suitable hydraulic turbine oil will have superior water separating capacity as well as the capacity to maintain adequate fluidity at low temperatures. It will also have sufficient capacity to resist rust and corrosion, as well as the capacity to settle harmful water rapidly. Because of the large amounts of water in the environment, a suitable hydraulic turbine oil will have minimum tendency to foam, retain air, and/or form sludge. A suitable general-application turbine oil will have a series of desirable properties to accommodate various operating conditions across multiple types of modern industrial turbines. These properties include, for example, sufficiently high viscosity index (VI), adequate oxidation stability (and relatedly, long life), low varnish/sludge formation, high fire resistance, good water-separation capacity, improved rust and/or corrosion resistance and improved air release and foaming properties. Desired are improved lubricant compositions having improved oxidation stability and anti-corrosion properties, for example improved turbine oils, rust & oxidation oils, ashless hydraulic fluids, ashless driveline fluids or an a