Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic sulfur compound – wherein the sulfur is single bonded...
Reexamination Certificate
1997-09-24
2001-05-22
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic sulfur compound, wherein the sulfur is single bonded...
C508S391000, C508S518000, C508S572000, C508S574000, C508S586000
Reexamination Certificate
active
06235688
ABSTRACT:
The present invention relates to novel compositions comprising a substituted hydrocarbaryl lithium salt. In a further aspect, the invention relates to methods of preparing these compositions and their uses as deposit inhibitors and dispersancy improvers in lubricating oils. In another aspect, the invention relates to concentrates and lubricating oil formulations containing such novel compositions.
BACKGROUND OF THE INVENTION
There are many patent documents that teach processes for making alkali metal-containing compounds. Among these are Great Britain Patent Application No. 1,481,553, European Patent Application Nos. 168,111; 462,762; and 465,118; and U.S. Pat. Nos. 4,302,342 and 4,867,891. Although lithium is disclosed as a possible alkali metal in making many of these compounds, in most of these formulations potassium and especially sodium are taught as preferred metals. In none of these above patents are processes to make lithium-containing compounds specifically exemplified.
There are also patent documents that teach lithium containing compounds are useful in lubricating oil compositions. U.S. Pat. Nos. 3,351,552; 3,634,240; 3,990,979; and 4,012,330 are examples of patents that teach lithium succinates as corrosion inhibitors in lubricating oil compositions.
U.S. Pat. No. 3,990,979 teaches half lithium salts of aliphatic hydrocarbon substituted succinic anhydrides and acids, which are reacted with polyhydric alcohols to provide an effective rust and corrosion inhibiting additive. These half lithium salts can be solubilized with alkyl phenols as a solvent aid in a physical mixture to prevent gelling, possibly forming a lithium phenate complex.
U.S. Pat. No. 2,951,808 teaches thixotropic mono- and di-metal salts of salicylic acids as oxidation inhibitors in lubricating oil compositions, preferably in greases. While the salicylic acids can have C
1
-C
15
alkyl groups, all the examples teach salicylic acids that are free of alkyl groups. The metal salts can be lithium or sodium salts.
U.S. Pat. No. 4,176,075 teaches a grease formulation similar to U.S. Pat. No. 2,951,808, which also contain a dioxime compound. The metal salts can be lithium or sodium, and are thixotropic.
U.S. Pat. No. 3,711,407 teach suspensions of oil-insoluble lithium salts of salicylic acid prepared by saponifying an aliphatic alcohol ester of hydroxy benzoic acid and then removing water and alcohol formed in the reaction.
U.S. Pat. No. 4,497,931 teaches polymer compositions stabilized by the presence of soluble lithium ions. These compositions are formed from a molten mixture of polymer, antioxidant, and a lithium compound.
U.S. Pat. No. 3,492,229 teaches certain base fluids that are oxidatively stabilized by certain metal salts. The metal can be any alkali metal or bismuth or lanthanum. Specific lithium-ontaining compounds taught (Table I) are the phenoxy benzoate and phenyl azobenzoate.
There are many grease compositions that use lithium compounds, especially lithium salts of hydroxy fatty acids, as a thickener. For example, the above mentioned U.S. Pat. No. 2,951,808 teaches a mixed lithium/calcium soap of 12-hydroxy stearic acid.
U.S. Pat. No. 3,985,662 teaches grease compositions using a lithium methyl salicylate soap. Lithium methyl salicylate soaps are thixotropic solids.
There are a few patents that teach processes for making lithium-containing compounds used as lubricating oil detergents.
U.S. Pat. No. 4,797,217 teaches a process for making overbased lithium sulfonates from lithium hydroxide monohydrate (BN of at least 250). Control of water removal is described as being important to the process. It does not teach any specific formulations containing these compounds.
World Patent No. 92/18,587, in Example 9, teaches an overbased lithium carboxylate. It does not teach any specific formulations including this compound.
European Patent Application No. 731159 teaches overbased lithium sulfonates that have a BN of at least 240.
There are also many patent documents that teach formulations of alkali metal-containing compounds. Examples of these include U.S. Pat. Nos. 4,326,972; 4,952,328; 5,464,548; 5,486,300; and 5,490,945; and World Patent Nos. 87/01,722; 90/15,124; 92/18,588; 93/23,504; 93/23,505; and 95/34,619. Although lithium is disclosed as a possible alkali metal compound in the making of many of these formulations, potassium and especially sodium are taught as preferred metals.
U.S. Pat. No.4,129,508 teaches an additive mixture of at least one reaction product of a hydrocarbon-substituted succinic acid or anhydride with at least one polyalkylene glycol or monoether thereof, at least one organic basic metal salt, and at least one alkoxylated amine. The basic metal can be magnesium, calcium, barium, lithium, or sodium. Example 14 shows a lithium alkyl benzene sulfonate having an apparent BN of at least 200.
There are a few patents that teach mixtures of lithium containing compounds and Group II metal-containing compounds. For example, European Patent Application No. 731,159 teaches a mixture of an overbased lithium-containing sulfonate detergent and an overbased non-lithium containing detergent. Great Britain Patent Application No. 1,365,311, in Example One, teaches a lubricating oil composition that contains both a neutral lithium salt of a polyisobutenyl succinic anhydride and an overbased sulfurized calcium phenate.
U.S. Pat. No. 5,030,687 in Example One teaches an overbased phenate/salicylate detergent (BN of at least 242) that contains a mixture of calcium and alkali metals. The alkali metal can be lithium, sodium, or potassium.
None of the prior art teaches that low BN lithium salts of substituted hydrocarbaryls give excellent black sludge dispersancy and deposit control in lubricating oil compositions.
U.S. Pat. Nos. 2,951,808; 3,351,552; 3,492,229; 3,634,240; 3,711,407; 3,985,662; 3,990,979; 4,012,330; 4,129,508; 4,176,075; 4,302,342; 4,326,972; 4,497,931; 4,797,217; 4,867,891; 4,952,328; 5,030,687; 5,464,548; 5,486,300; and 5,490,945 are hereby incorporated by reference in their entirety for all purposes.
SUMMARY OF THE INVENTION
The present invention provides an essentially sodium free, non-thixotropic oil lubricant additive that gives excellent black sludge dispersancy and deposit control in lubricating oil compositions.
The lubricant additive must be essentially free of sodium because sodium salts so are often used as leak indicators in coolants. If sodium is present in the final product, it will cause false positives in the detection of coolant leaks.
In one embodiment, the lubricant additive is also essentially free of potassium. Potassium is undesirable because potassium salts are sometimes used as leak indicators in coolants. Potassium is also undesirable because it contributes substantially to sulfated ash.
The lubricant additive comprises from 10% to 50% of a liquid organic diluent and from 30% to 90% of a substituted hydrocarbaryl metal salt, wherein at least 30 mole percent of the metal in the salt is lithium. Some of the metal can be a Group II metal, such as calcium. Preferably, at least 90 mole percent of the metal is lithium. More preferably, it is essentially free of other metals.
The substituted hydrocarbaryl metal salt can be, but is not limited to, phenates, sulfurized phenates, aromatic sulfonates, salicylates, sulfurized salicylates, salts of multi-hydroxy aromatic compounds, salts of sulfurized multi-hydroxy aromatic compounds, hydroxy aromatic sulfonates, or chemical and physical mixtures thereof, that are substituted with an alkyl or alkenyl group, preferably having from 6 to 40 carbon atoms.
The substituted hydrocarbaryl metal salt can be a neutral detergent (BN in the range of about from 0 to 30), a normal detergent (BN in the range of about from 30 to 150), a moderately overbased detergent (BN in the range of about from 150 to 225), or a high BN, overbased detergent (BN of about 225 or higher), but the BN attributable to lithium must be less than about 150.
Because of the high cost of lithium sources, it is not economical to use lithium as the primary BN sour
Coent Jean-Louis Le
Polhaar Gerrit J.
Small Vernon R.
Suwandi Ita Suharti
Willis, Jr. William Woodford
Chevron Chemical Company LLC
McAvoy Ellen M.
Sheridan Richard J.
Stumpf Walter L.
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