Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Heterocyclic ring compound; a heterocyclic ring is one...
Reexamination Certificate
2002-11-14
2003-11-11
Howard, Jacqueline V. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Heterocyclic ring compound; a heterocyclic ring is one...
C508S410000, C508S436000, C508S563000, C508S569000
Reexamination Certificate
active
06645920
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the use of an additive composition that contains at least two antioxidants and at least one rust inhibitor in lubricating oils. The invention further relates to the process to make the novel additive composition and its use in industrial fluids.
BACKGROUND OF THE INVENTION
Protecting against oxidation degradation by selecting the proper balance of oxidation inhibitor components can significantly improve the life of a lubricant. Oxidation occurs when oxygen attacks the petroleum fluid, which leads to increased viscosity and deposit formation in the fluid. The oxidation process contributes to the formation of sludge in oils and the breakdown of viscosity characteristics of the lubricant.
Rust inhibitors primarily protect against seizure, rust and corrosion by preventing the oxidation of iron in steel. Selecting the propel balance of rust inhibitor components can significantly improve the life of a lubricant. Often rust inhibitors contain carboxylic functionality and are described as acidic. Common acidic rust inhibitors are derivatives of alkenyl succinic anhydride, particularly polyisobutene succinic anhydride. Polyisobutene succinic anhydrides used as rust inhibitors react with divalent metals such as calcium and/or zinc from metal detergents or other metal contaminants to produce sludge and other particulate matter. Sludge and other particulate matter are detrimental in industrial fluid systems.
U.S. Pat. No. 4,101,429 exhibits the problems associated with rust inhibitors containing polyisobutene succinic anhydrides mentioned above. The technology disclosed relates to the use of polyisobutene succinic anhydride in combination with zinc primary dihydrocarbyl dithiophosphate in turbine oils to produce a formulation with acceptable levels of thermal stability, oxidation stability, low wear, water compatibility and filtration properties. However the polyisobutene succinic anhydride reacts with metal detergents or other metal contaminants to produce particulate material that accumulates and results in plugging the fine filters used in turbine oils.
European Patent Number 978,554 discloses the use of a lubricating oil composition suitable for turbines with improved wet filterability containing at least one neutral rust inhibitor to prevent oxidation and rust. Rust inhibitors used in this invention include hydrocarbyl esters such as R (COOR′)n, in which R and R′ are each independently hydrocarbyl groups, or hydroxyhydrocarbyl groups, containing up to about 40 carbon atoms, and n is 1 to 4. Other neutral rust inhibitors are aspartic acid diesters of 1-(2-hydroxyethyl)-2-heptadecenyl imidazoline. The imidazolines are primarily a mixture of diester of L-aspartic acid and an imidazoline based on the reaction between oleic acid and aminoethanolamine. Combinations of the rust inhibitors are used in the presence of a succinimide compound. However, no metal deactivator is used.
U.S. Pat. No. 4,088,587 relates to the use of a lubricating oil additive composition with improved antioxidant properties comprising sterically hindered phenols or thiophenols, oil soluble aromatic amines and an organic sulphur compound and a phosphorus containing compound. The sulphur containing compound contains 3 to 40 weight percent of sulphur in the form of a sulphide, polysulphides or mixtures thereof. Examples of sulphur compounds suitable include sulphurised fatty esters, sulphurised hydrocarbons and particularly useful are sulphurised metal phenates. The phosphorus compounds are prepared by reacting phosphorus oxychloride or phosphorus thiochloride with 1,2-substituted imidazolines. The phosphorus containing compounds do not contain amine functionality. Furthermore, no rust inhibitors are used.
U.S. Pat. No. 4,161,451 relates to the use of a composition which imparts improved oxidation properties to lubricants using an antioxidant selected from alkyl and aromatic sulphides and polysulphides, sulphurised oletins, sulfurised carboxylic acid esters and sulphurised ester olefins and a secondary aliphatic amine. Antioxidant properties are obtained by the synergistic effect from the sulphur containing antioxidant and the secondary aliphatic amine. In one embodiment, an oil soluble zinc salt is present and is used in combination with the sulphur containing antioxidant and the secondary aliphatic amine. The composition does not contain rust inhibitors.
U.S. Pat. No. 5,091,099 relates to the use of a phosphite free lubricating oil composition containing a mixture of at least one aromatic amine e.g. alkylated diphenylamine and at least one sterically hindered phenol. The composition does not contain a sulphurised antioxidant.
It would be desirable to produce a lubricating oil composition that does not substantially react with zinc and/or calcium and is capable of imparting acceptable levels of rust and/or oxidation inhibition without the formation of unwanted deposits that increases the viscosity of the fluid. Furthermore, it would be desirable to produce a lubricating oil composition capable of preventing filter plugging deposits and/or sludge in industrial fluids.
The present invention provides a lubricating oil composition capable of imparting good levels of rust and/or oxidation inhibition. The invention further provides a lubricating oil composition capable of preventing the formation of filter plugging deposits and sludge caused by acidic rust inhibitors in lubricating oils.
SUMMARY OF THE INVENTION
The invention relates to a lubricating oil composition comprising:
a) an oxidation package comprising:
(i) an alkylated diphenylamine,
(ii) a substituted hydrocarbyl monosulphide, and
(iii)optionally, a sterically hindered phenol;
b) a rust inhibitor selected from the group comprising hydrocarbyl amine salts of alkylphosphoric acid, hydrocarbyl amine salts of dialkylphosphoric acid, hydrocarbyl amine salts of hydrocarbyl aryl sulphonic acid or mixtures thereof; and
c) a metal deactivator;
d) optionally other additives; and
e) an oil of lubricating viscosity.
The invention further provides a process for the preparation of lubricating oil compositions, comprises mixing and/or dissolving a metal deactivator, an oxidation package, at least one rust inhibitor, and optional additives selected from the group consisting of a foam inhibitor, demulsifier or a viscosity modifier or a pour point depressant and combinations thereof in a base oil or diluent oil.
The invention further provides a lubricating oil composition that is capable of preventing filter plugging deposits and sludge. The invention further provides for a lubricating oil composition with good levels of rust and/or oxidation inhibition without the detrimental effects of the formation of filter plugging deposits and sludge caused by acidic rust inhibitors in lubricating oils. The invention further provides a lubricating oil composition suitable for industrial fluids, hydraulic fluids, turbine oils and circulating oils.
DETAILED DESCRIPTION OF THE INVENTION
A novel lubricating oil composition has been found to prevent filter plugging deposits and sludge. This is achieved by using a lubricating oil composition comprising:
a) an oxidation package comprising:
(i) an alkylated diphenylamine,
(ii) a substituted hydrocarbyl monosulphide, and
(iii) optionally, a sterically hindered phenol;
b) a rust inhibitor selected from the group comprising hydrocarbyl amine salts of alkylphosphoric acid, hydrocarbyl amine salts of dialkylphosphoric acid, hydrocarbyl amine salts of hydrocarbyl aryl sulphonic acid or mixtures thereof;
c) a metal deactivator;
d) optionally other additives; and
e) an oil of lubricating viscosity.
Oxidation Package
The oxidation package includes but is not limited to alkylated diphenylamines that can be represented by the following formula:
wherein R
1
and R
2
are independently hydrogen or an arylalkyl group containing about 5 to about 20, preferably about 6 to about 10 carbons atoms; or a linear or branched alkyl group containing 1 to 24 carbon atoms and q is independently 0, 1, 2, or
Esposito Michael F.
Gilbert Teresan W.
Howard Jacqueline V.
The Lubrizol Corporation
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