Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
1999-04-21
2002-05-21
Howard, Jacquline V. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
C508S364000, C508S379000
Reexamination Certificate
active
06391833
ABSTRACT:
The present invention relates to low sulfur lubricant compositions having excellent detergency properties suitable for use in two-stroke engines, low sulfur detergency additives useful in those low sulfur lubricant compositions, fuels containing those low sulfur detergency additives, and concentrates of those low sulfur detergency additives.
BACKGROUND OF THE INVENTION
Over the past several decades the use of spark ignited two-stroke internal combustion engines has steadily increased. They are presently found in power lawn mowers and other power operated garden equipment, power chain saws, pumps, electrical generators, marine outboard engines, snowmobiles, motorcycles and the like.
The increasing use of two-stroke cycle engines, coupled with increasing severity of the conditions in which they have operated, has led to an increased demand for oils to adequately lubricate such engines. Among the problems associated with two-stroke cycle engines is piston lubricity, scuffing or scoring. Lubricating oils often contain sulfur, a key element in anti-wear performance. Much of the sulfur contribution comes from the detergent-dispersant additives used in the lubricating oils. However, the level of sulfur has become environmentally sensitive and a move toward lower sulfur levels is increasing. One of the drivers has been the presence of low sulfur base oils in some parts of the world. Low sulfur lubricating oil additive packages are not common.
The unique problems and techniques associated with the lubrication of two-stroke cycle engines has led to the recognition by those skilled in the art of two-stroke cycle engine lubricants as a distinct lubricant type. See, for example, U.S. Pat. Nos. 3,085,975; 3,004,837; and 3,753,905.
U.S. Pat. No. 4,663,063 discloses a functional fluid for a two-cycle engine having base oil and a combination of an alkylated phenol and a polyalkylene polyamine. That patent discloses that metal thiocarbamates are useful as extreme pressure agents.
U.S. Pat. No. 5,516,444 discloses a functional fluid for a two-cycle engine having base oil and an acylated nitrogen-containing compound having an oil soluble olefinic substituent and at least one ashless detergent/dispersant. That patent discloses that molybdenum- and molybdenum/sulfur-containing compounds are some of the anti-wear and lubricity agents useful in that invention.
U.S. Pat. No. 5,458,807 discloses a lubricating oil composition useful in automobiles and various industrial internal combustion engines. That lubricating oil composition has base oil, a boron compound derivative of alkenylsuccinimide, an alkaline earth metal salt of salicylic acid, and a molybdenum compound.
U.S. Pat. No. 5,688,751 discloses alkali metal salicylate salts as lubricant additives for two-cycle engines.
SUMMARY OF THE INVENTION
The present invention provides a low sulfur (<0.2%) detergency additive especially useful in lubricant composition used in air-cooled two-stroke cycle engines. That low sulfur detergency additive comprises an unsulfurized alkaline earth alkylsalicylate and optionally a molybdenum compound. Alkylphenol and alkaline earth alkylphenate can also be present in the low sulfur detergency additive.
Preferably, the unsulfurized alkaline earth alkylsalicylate is calcium alkylsalicylate wherein the mole ratio of single aromatic-ring alkylsalicylate to double aromatic-ring alkylsalicylate in said unsulfurized alkaline earth alkylsalicylate is at least 8:1.
The present invention also provides a low sulfur lubricant composition suitable for air-cooled two-stroke cycle engines. This lubricant composition has a major amount of low sulfur oil of lubricating viscosity and a minor amount of the low sulfur detergency additive. Preferably, the lubricant composition also has a minor amount of a non-aromatic solvent, a minor amount of a polyisobutene, and/or a minor amount of an ashless dispersant. The lubricating oil composition can be produced by blending together a major amount of the oil of lubricating viscosity, a minor amount of low sulfur detergency additive, and preferably minor amounts other additives, such as non-aromatic solvent, polyisobutene, and an ashless dispersant. The low sulfur lubricant composition can be used to lubricate an air-cooled two-stroke cycle engine by supplying the lubricant composition to the engine crankcase and operating the engine or by supplying the lubricant composition to the fuel and operating the engine.
The present invention also provides an additive concentrate suitable for mixing with base oil to provide lubricating oils which may be used to lubricate air-cooled two-stroke cycle engines. This additive has a minor amount of an organic diluent, plus from 20 to 80% of the low sulfur detergency and preferably a non-aromatic solvent, a polyisobutene, and/or an ashless dispersant.
DETAILED DESCRIPTION OF THE INVENTION
In its broadest aspect, the present invention involves a low sulfur detergency additive having excellent detergency properties when used in a low sulfur lubricant composition for air-cooled two-stroke engines. The low sulfur detergency additive comprises an unsulfurized alkaline earth alkylsalicylate and optionally a molybdenum compound.
Prior to discussing the invention in further detail, the following terms will be defined:
Definitions
As used herein the following terms have the following meanings unless expressly stated to the contrary:
The term “low sulfur” means less than 0.2% sulfur, including no sulfur.
The term “alkylphenol” means a phenol group having one or more alkyl substituents; at least one of which has a sufficient number of carbon atoms to impart oil solubility to the phenol.
The term “alkaline earth metal” means calcium, barium, magnesium, and strontium.
The term “alkaline earth alkylphenate” means an alkaline earth metal salt of an alkylphenol.
The term “alkaline earth alkylsalicylate” means an alkaline earth metal salt of an alkyl salicylic acid.
The term “alkaline earth single aromatic-ring alkylsalicylate” means an alkaline earth alkylsalicylate having only one alkyl salicylic anion per each alkaline earth metal base cation. Thus one mole of alkaline earth single aromatic-ring alkylsalicylate will contain one mole of aromatic ring and one mole of alkaline earth base cation. Thus, a calcium single aromatic-ring alkylsalicylate would have one aromatic ring for each calcium ion.
The term “alkaline earth double aromatic-ring alkylsalicylate” means an alkaline earth alkylsalicylate having two alkyl salicylic anions per each alkaline earth metal base cation. Thus one mole of alkaline earth double aromatic-ring alkylsalicylate will contain two mole of aromatic rings and one mole of alkaline earth base cation. Thus, a calcium double aromatic-ring alkylsalicylate would have two aromatic rings for each calcium ion.
The term “Base Number” or “BN” refers to the amount of base equivalent to milligrams of KOH in one gram of sample. Thus, higher BN numbers reflect more alkaline products, and therefore a greater alkalinity reserve. The BN of a sample can be determined by ASTM Test No. D2896 or any other equivalent procedure.
Unless otherwise specified, all percentages are in weight percent and all molecular weights are number average molecular weights.
Base Oil Of Lubricating Viscosity
The present invention relates to lubricating oil compositions and to lubricant fuels suitable for use in two-stroke engines. The lubricating compositions useful for two-stroke cycle engines will compose a major amount by weight of at least one base oil of lubricating viscosity and a minor amount of the present additives, sufficient to control piston ring sticking, reduce rust formation, and promote general engine cleanliness.
The lubricating compositions and methods of this invention employ oils of lubricating viscosity, including natural or synthetic lubricating oils and mixtures thereof. While conventional base oils might have 0.4% sulfur, the base oils of the present invention must have less than 0.2% sulfur, preferably less than 0.1% sulfur. Natural oils include, for example, animal o
Addagarla Sumanth
Cazin Jacques
Ilmain Frank
Chevron Chemical S.A.
Fallon Martin C.
Howard Jacquline V.
Sheridan Richard J.
Stokley Linda A.
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