Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Nitrogen and heavy metal – or nitrogen and aluminum – in the...
Reexamination Certificate
2000-03-23
2003-03-04
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Nitrogen and heavy metal, or nitrogen and aluminum, in the...
C508S362000, C554S038000, C554S071000, C556S057000
Reexamination Certificate
active
06528463
ABSTRACT:
TECHNICAL FIELD
The present invention relates to novel organic molybdenum complexes and their use as multifunctional additives for lubricating compositions. The novel molybdenum compositions of the present invention comprise the reaction products of a long-chain monocarboxylic acid, a mono-alkylated alkylene diamine, glycerides, and a molybdenum source.
BACKGROUND OF THE INVENTION
Lubricating oils for internal combustion engines of automobiles or trucks are subjected to a demanding environment during use. This environment results in the oil suffering oxidation that is catalyzed by the presence of impurities in the oil such as iron compounds and is also promoted by the elevated temperatures of the oil during use. This oxidation of lubricating oils during use is typically controlled to some extent by the use of antioxidant additives that may extend the useful life of the oil, particularly by reducing or preventing unacceptable viscosity increases.
Further, there have been many attempts to use lubricants to reduce the friction in an internal combustion engine so as to reduce the fuel consumption of the engine. Numerous classes of lubricant additives have been suggested for use as friction modifiers and to increase the energy efficiency provided to an engine by a lubricant.
Molybdenum containing additives are known to deliver a variety of beneficial properties to lubricants. Examples of lubricants that benefit from the addition of molybdenum are passenger car motor oils, natural gas engine oils, heavy-duty diesel oils, and railroad oils. Over the years molybdenum, when used properly, has been shown to deliver improved anti-wear protection, improved oxidation control, improved deposit control, and improved friction modification for fuel economy. There are many examples in the patent literature showing the use of molybdenum additives as antioxidants, deposit control additives, anti-wear additives and friction modifiers. A partial list of molybdenum-containing lubricant patents is provided below:
U.S. Pat No. 5,840,672
U.S. Pat No. 5,814,587
U.S. Pat No. 4,529,526
WO 95/07966
U.S. Pat No. 5,650,381
U.S. Pat No. 4,812,246
U.S. Pat No. 5,458,807
WO 95/07964
U.S. Pat No. 5,880,073
U.S. Pat No. 5,658,862
U.S. Pat No. 5,696,065
WO 95/07963
U.S. Pat No. 5,665,684
U.S. Pat No. 4,360,438
U.S. Pat No. 5,736,491
WO 95/27022
U.S. Pat No. 5,786,307
U.S. Pat No. 4,501,678
U.S. Pat No. 5,688,748
EP 0 447 916 A1
U.S. Pat No. 5,807,813
U.S. Pat No. 4,692,256
U.S. Pat No. 5,605,880
WO 95/07962
U.S. Pat No. 5,837,657
U.S. Pat No. 4,832,867
U.S. Pat No. 4,705,641
EP 0 768 366 A1
Numerous oil-soluble molybdenum compounds and their methods of preparation have been described in the art. For example, glycol molybdate complexes are described by Price et al. in U.S. Pat. No. 3,285,942; overbased alkali metal and alkaline earth metal sulfonates, phenates and salicylate compositions containing molybdenum are disclosed and claimed by Hunt et al in U.S. Pat. No. 4,832,857; molybdenum complexes prepared by reacting a fatty oil, a diethanolamine and a molybdenum source are described by Rowan et al in U.S. Pat. No. 4,889,647; a sulfur and phosphorus-free organomolybdenum complex of organic amide, such as molybdenum containing compounds prepared from fatty acids and 2-(2-aminoethyl) aminoethanol are taught by Karol in U.S. Pat. No. 5,137,647; overbased molybdenum complexes prepared from amines, diamines, alkoxylated amines, glycols and polyols are described by Gallo et al in U.S. Pat. No. 5,143,633; and 2,4-heteroatom substituted-molybdena-3,3-dioxacycloalkanes are described by Karol in U.S. Pat. No. 5,412,130.
Existing molybdenum technology, however, suffers from a number of problems that have limited its widespread use in lubricants. These problems include color, oil solubility, cost and corrosion.
Color—Many molybdenum technologies that appear in the patent literature deliver high levels of color when used even at moderate levels in crankcase oils. A non-discoloring molybdenum source is important because highly colored oils imply to the end consumer that the oil is “used” and therefore not capable of delivering the maximum amount of protection to the engine. When these highly colored molybdenum sources are used at low levels, e.g. 100-150 ppm delivered molybdenum as is typically required for oxidation, deposit and wear control, discoloration is not substantial but may still be visible. However, when these highly colored molybdenum compounds are used at high levels, e.g. 400-1000 ppm delivered molybdenum as is generally required for friction modification, discoloration is often significant. Traditionally, the color of fully formulated crankcase oils has been determined using the ASTM D 1500 color scale. Two types of unacceptable colors are possible. The first type of discoloration results in a dark rating on the D 1500 scale. The amount of acceptable finished lubricant darkening depends on the customer and application. There are no set standards for the amount of discoloration or darkening that is allowed. Generally, D 1500 ratings equal to or greater than 5.0 are considered unacceptable for a finished crankcase oil. Certain customers may find it difficult to market and sell such dark crankcase oils. The second type of discoloration produces “no match” on the D 1500 color scale. These finished lubricants, in addition to showing no match, are also very dark. Again, certain customers may find it difficult to market and sell such dark crankcase oils.
Oil Solubility—Many commercially available molybdenum additives designed for use in lubricants exhibit limited solubility in the finished lubricant product. For widespread use of a molybdenum product in lubricant applications the product must not only be soluble, at friction modifier treat levels, in the finished lubricant, it must also be soluble in the additive concentrates used to prepare the finished lubricant.
Cost—Molybdenum has long been viewed as an expensive additive for crankcase applications. Part of the reason for the high cost stems from the fact that many of the commercial molybdenum products have low levels, e.g. less than 5% by weight, of molybdenum in the additive. In some cases expensive organic ligands or expensive manufacturing processes are used to produce the commercial molybdenum compounds. There is a need for products with higher molybdenum contents that are prepared from lower cost raw materials.
Corrosion—Many molybdenum technologies that appear in the patent literature contain sulfur. The presence of sulfur in various crankcase applications is detrimental because certain types of sulfur are incompatible with elastomer seals and corrosive. Even the less aggressive forms of sulfur can be corrosive in very high temperature crankcase environments where significant amounts of oxygen and water are present. There are also trends to reduce the amount of sulfur present in finished crankcase lubricants. As these trends start to become a reality additives containing sulfur will become less desirable.
It is also well known that certain molybdenum containing friction modifiers function by a decomposition mechanism that results in the formation of a mixed molybdenum sulfide/molybdenum oxide layer on the metal surface of the engine. The molybdenum species that form on the metal surface can vary significantly and their composition is affected by the types of additives in the lubricant and the engine or test design. For example, it is known that molybdenum dithiocarbamates decompose when heated in use to produce products that include free amine and carbon disulfide. Both such products are aggressive towards copper that is present in the engine bearings. Furthermore, free amines are known to be aggressive towards certain types of elastomer seals present in a wide variety of engines. It is therefore desirable from a compatibility standpoint to develop new additives that are low in sulfur and free amines.
All of the above problems suggest a need for a molybdenum additive that has a high molybdenum content, low amine and sulfur content, good oil solubility, and no
Gatto Vincent James
Loper John T.
Mike Carl A.
Ethyl Corporation
McAvoy Ellen M.
Rainear Dennis H.
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