Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic compound containing boron
Reexamination Certificate
1999-10-19
2002-11-19
Howard, Jacqueline V. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic compound containing boron
C508S192000, C508S269000, C508S371000, C508S375000, C508S435000, C508S436000, C508S438000
Reexamination Certificate
active
06482777
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to lubricating compositions which contain a combination of additives which provide improved friction, and thermal stability properties to lubricating compositions. The lubricating compositions contain the combination of (A) a fatty saturated phosphate, and optionally (B) at least one alkyl imidazoline or a reaction product of a carboxylic acid and a polyamine, and/or (C) a borated dispersant overbased composition.
BACKGROUND OF THE INVENTION
Although conventional differentials generally perform satisfactory under normal conditions, they suffer from a drawback called stalling. Stalling is the phenomenon which occurs when one wheel loses traction and the vehicle does not move. The reason for this is related to the design of the differential, where all of the driving torque is taken away by the wheel with less traction. Limited-slip differential designs overcome stalling by the use of clutch plates or friction cones. These devices help transfer more power to the wheel with traction. The result is that both wheels spin and the automobile moves. The common problem with these devices is the noise or chatter resulting from stick-slip (engagement-disengagement) phenomenon that occurs between the elements of clutches at low speeds. Additives, called friction modifiers, are used to impart proper frictional characteristics to the lubricant to overcome this problem.
As a general rule, friction modifiers hurt the performance of antiwear and/or extreme pressure additives. Generally, the antiwear or extreme pressure additives in lubricants reduce damage by maintaining a layer of lubricant between the moving parts of the equipment. The additives of the lubricant which provide antiwear or extreme pressure help reduce harmful metal on metal contact. There is a need for lubricants for limited slip axles which provide a balance between frictional properties and antiwear/extreme pressure properties.
Thermal stability of the lubricant is another important parameter. Traditional lubricants are unable to endure high operating temperatures of today's equipment and tend to decompose in the bulk and are not available when and where needed. There is a need for those lubricants to be thermally stable. One measure of thermal stability is the ASTM L-60 test. The antiwear extreme pressure protection is generally reflected in the ASTM L-42 and ASTM L-37 tests.
“Top treatments” are a combination of additives which are added on top of existing lubricants to improve certain properties. It is desirable to have a top treatment that may be added to a API GL-4 or GL-5 and MIL-PRF-2105E lubricant packages to provide friction and optionally thermal stability.
SUMMARY OF THE INVENTION
This invention relates to a lubricating composition comprising a blend of a major amount of an oil of lubricating viscosity, gear or transmission oil package and a top treatment which comprises at least one saturated fatty phosphate ester or salt, wherein the lubricating composition is free of saturated fatty phosphites. Tin another embodiment, the invention relates to a lubricating composition comprising a major amount of an oil of lubricating viscosity, at least one saturated fatty phosphate ester or salt, at least one polysulfide and at least one phosphorus antiwear or extreme pressure agent, wherein the lubricating composition is free of saturated fatty phosphites. The invention relates to additive combinations which when added to a lubricant can provide and improve frictional and, optionally, thermal stability properties. The additives include a phosphate ester or salt wherein the hydrocarbyl group of the phosphate is a fatty-saturated group. The top treatment may also include a substituted fatty imidazoline or reaction product of a fatty carboxylic acid and polyalkylene polyamine and/or a borated dispersant.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The term “hydrocarbyl” includes hydrocarbon as well as substantially hydrocarbon groups. Substantially hydrocarbon describes groups which contain heteroatom substituents which do not alter the predominantly hydrocarbon nature of the group. Examples of hydrocarbyl groups include the following:
(1) hydrocarbon substituents, i.e., aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, aromatic-, aliphatic- and alicyclic-substituted aromatic substituents and the like as well as cyclic substituents wherein the ring is completed through another portion of the molecule (that is, for example, any two indicated substituents may together form an alicyclic radical);
(2) substituted hydrocarbon substituents, i.e., those substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon nature of the substituent; those skilled in the art will be aware of such groups (e.g., halo (especially chloro and fluoro), hydroxy, mercapto, nitro, nitroso, sulfoxy, etc.);
(3) heteroatom substituents, i.e., substituents which will, while having a predominantly hydrocarbon character within the context of this invention, contain an atom other than carbon present in a ring or chain otherwise composed of carbon atoms (e.g., alkoxy or alkylthio). Suitable heteroatoms will be apparent to those of ordinary skill in the art and include, for example, sulfur, oxygen, nitrogen and such substituents as, e.g., pyridyl, furyl, thienyl, imidazolyl, etc.
In general, no more than about 2, preferably no more than one, hetero substituent will be present for every ten carbon atoms in the hydrocarbyl group. Typically, there will be no such heteroatom substituents in the hydrocarbyl group. Therefore, the hydrocarbyl group is purely hydrocarbon.
As described above, the above additives include top treatments for existing lubricating compositions. In another embodiment, the additives are used in lubricating compositions described herein. Specifically, these top treatments provide improved friction and, optionally, thermal stability properties to gear or transmission lubricants. The gear lubricants typically include API GL-4 and GL-5 formulations and API GL-5 API MT-1 formulations.
Fatty Phosphates
As described above, the lubricant additive may be a phosphate ester or salt. The phosphate ester or salt is present at a level to provide from about 0.25% to about 4%, or from about 0.5% to about 2%, or from about 0.75% to about 1.5% phosphate ester or salt to the lubricant. Here and elsewhere in the specification and claims, the range and ratio limits may be combined. The top treatment typically contains a major amount of the phosphate ester or salt. More specifically, the phosphate ester or salt is present in an amount from about 55% to about 100%, or from about 65% to about 95%, or from about 75% to about 90% by weight of the additives of the top treatment.
The phosphate ester or salt may be a monohydrocarbyl, dihydrocarbyl or a trihydrocarbyl phosphate, wherein each hydrocarbyl group is saturated. In one embodiment, each hydrocarbyl group independently contains from about 8 to about 30, or from about 12 up to about 28, or from about 14 up to about 24, or from about 14 up to about 18 carbons atoms. In one embodiment, the hydrocarbyl groups are alkyl groups. Examples of hydrocarbyl groups include tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl groups and mixtures thereof.
In one embodiment, phosphate ester or salt is a phosphorus acid ester prepared by reacting one or more phosphorus acid or anhydride with a saturated alcohol. The phosphorus acid or anhydride is generally an inorganic phosphorus reagent, such as phosphorus pentoxide, phosphorus trioxide, phosphorus tetroxide, phosphorous acid, phosphoric acid, phosphorus halide, lower phosphorus esters, or a phosphorus sulfide, including phosphorus pentasulfide, and the like. Lower phosphorus acid esters generally contain from 1 to about 7 carbon atoms in each ester group. Alcohols used to prepare the phosphorus acid esters or salts. Examples of commercially available alcohols and alcohol mixtures include Alfol 121
Esposito Michael F.
Gilbert Teresan W.
Howard Jacqueline V.
The Lubrizol Corporation
Tritt William C.
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