Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
2000-03-28
2001-07-31
Johnson, Jerry D. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
C508S492000, C508S569000
Reexamination Certificate
active
06268319
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to lubricant compositions and methods of making and using the lubricant compositions and, more particularly, to slide way lubricant compositions and methods of making and using the same.
2. Description of the Related Art
In industrial manufacturing processes, a way table (or way slide) is commonly used to move a work piece between machining stations. A way table is typically mounted on a carriage having bearing surfaces lubricated with a way lubricant. The carriage moves on slide-ways engaged to the carriage in a parallel fashion on the bearing surfaces. The bearings are also known in the industry as flat bearings, and they include slides, guides, and ways on machine tools.
Metal working operations generally use coolants. As such, the way table is mounted above a coolant reservoir into which the metal working coolants flow. By the very nature of their chemistry, the coolants are capable of dissolving oils. The dissolved oils are mainly way lubricants which are washed off the flat bearings, becoming dissolved into the coolant fluid. Because of their high degree of sulfur and phosphorus content, conventional way lubricants create ideal conditions for bacterial and fungal growth in the coolant, thereby degrading the coolant and creating an environment that can affect the workers safety by causing, e.g., dermatitis and respiratory ailments. Moreover, this creates a condition that contributes to increased waste water and waste oil quantities. There is, therefore, a need for an improved way lubricant which contains less sulfur and phosphorus than conventional way lubricants, while still performing up to industry standards.
Way lubricants preferably exhibit excellent boundary lubrication, possess properties which prevent metal to metal contact even under extreme pressure, and have good adherence to the metallic surfaces while in a flooded condition caused by the continued circulation of the metal working coolant over the lubricant. Due to its chemical nature, the coolant exhibits a cleaning action, thereby washing the lubricant into the coolant reservoir. Not only does the coolant wash the lubricant away from the metallic surfaces, the pressure exerted on the bearing surface by the weight of the way table forces the lubricant away from the bearing surfaces. The reduced level of way lubricant on the bearings creates chatter or stick/slip conditions and reduces machine and tool performance. There is, therefore, a need for an improved way lubricant which has better adherence to the metal surfaces even under high pressures and coolant-flooded conditions.
Therefore, the present invention seeks to provide an improved slide way lubricant which contains less sulfur and phosphorus than conventional way lubricants, while exhibiting a better adherence to the metal surfaces even under high pressures and coolant-flooded conditions. Methods of making and using these improved slide way lubricants are disclosed which are also advantageous.
SUMMARY OF THE INVENTION
In accordance with the present invention, a slide way lubricant composition is disclosed which includes (a) a hydrotreated petroleum having a viscosity of from about 10 cSt to about 250 cSt as measured at 40° C., consisting predominantly of hydrocarbons having from about 15 to about 50 carbon atoms per molecule, in combination with at least (b) a polymeric synthetic ester having an average molecular weight of at least about 200,000. Typically, the hydrotreated petroleum is employed in an amount of from about 97.8 to about 99.4 weight percent, while the ester is employed in the composition in an amount of from about 0.6 to about 2.2 weight percent, the weight percents being based on the total weight of the composition.
Preferably, the ester is derived from the reaction between a dicarboxylic acid and a polyhydric alcohol, and, more preferably, from the reaction between a dicarboxylic acid having from a total of four to eight carbon atoms and a polyhydric alcohol having a total of three to seven carbon atoms.
The lubricant composition may further include one or more other additives, the first being a synthetic polymeric adhesion additive having an average molecular weight of at least about 1,000,000. Furthermore, a sulfurized synthetic high pressure agent, such as a trisulfide may also be added to achieve certain properties. If used, the adhesion additive may be present in an amount of from about 0.1 to about 0.15 weight percent based on the weight of the composition, and the high pressure agent may be present in an amount of from about 0.1 to about 0.6 weight percent based on the weight of the ester.
Another embodiment of the present invention is a method of making the slide way lubricant composition. The method includes heating the hydrotreated petroleum to a temperature of from about 90° F. to about 120° F. and blending into the heated hydrotreated petroleum the polymeric synthetic ester and any other components desired.
Yet another embodiment of the present invention is a method of lubricating a slide way having bearings. This method includes applying a lubricant composition to the bearings wherein the lubricant composition includes a hydrotreated petroleum having a viscosity of from about 10 cSt to about 250 cst as measured at 40° C. and consisting predominantly of hydrocarbons having from about 15 to about 50 carbon atoms per molecule. The hydrotreated petroleum is employed in an amount of from about 97.8 to about 99.4 weight percent based on the weight of the lubricant composition.
Other advantages of the present invention will be readily appreciated as the same becomes better understood after reading the subsequent description.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
The present invention discloses a slide way lubricant composition, a method of making a slide way lubricant composition, and a method of using a slide way lubricant composition. The slide way lubricant composition of the present invention contains a) hydrotreated petroleum; and b) at least a polymeric synthetic ester to reduce the coefficient of friction of the composition. The preferred lubricant composition may also contain one or more of the following: c) a high pressure agent; d) an adhesion additive; and e) a demulsibility agent. The lubricant compositions of the present invention also have the advantage that they may be formulated to be free of antioxidants, which are typically phenolic compounds.
I. Composition
A. Hydrotreated Petroleum
The main ingredient, or base oil, of the present lubricant composition is the hydrotreated petroleum. A desirable hydrotreated petroleum will have a viscosity of from about 10 cSt to about 250 cSt as measured at 40° C. and is predominantly a complex combination of hydrocarbons having from about 15 to about 50 carbon atoms per molecule. The preferred viscosity of the hydrotreated petroleum ranges from about 30 to about 220 cSt as measured at 40° C.
Some specific examples of suitable hydrotreated petroleums are defined by industry standard CAS #'s 72623-86-0, 72623-87-1, and 72623-85-9. The petroleum defined by CAS # 72623-86-0 is predominantly a complex combination of hydrocarbons having from 15 to 30 carbon atoms per molecule and has a viscosity of about 15 cSt as measured at 40° C. The petroleum defined by CAS # 72623-87-1 is predominantly a complex combination of hydrocarbons having from 20 to 50 carbon atoms per molecule and has a viscosity of about 32 cSt at 40° C. The petroleum defined by CAS # 72623-85-9 is predominantly a complex combination of hydrocarbons having from 20 to 50 carbon atoms per molecule and has a viscosity of about 112 cSt at 40° C.
The petroleum defined by CAS # 72623-86-0 is prepared by treating widely available light vacuum gas oil and heavy vacuum gas oil with hydrogen in the presence of a catalyst in a two stage process with dewaxing being carried out between the two stages. The petroleums defined by CAS #'s 72623-87-1 and 72623-85-9 are prepared by treating light vacuum ga
Cargill Lynn E.
General Oil Company
Johnson Jerry D.
LandOfFree
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