Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Inorganic compound
Reexamination Certificate
2001-09-28
2003-03-18
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Inorganic compound
C508S156000, C508S306000, C508S287000, C508S390000
Reexamination Certificate
active
06534450
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed, in part, to novel dispersed hydrated sodium borate compositions, as well as additive packages and finished oil compositions comprising the same. The dispersed hydrated sodium borate compositions of this invention exhibit decreased turbidity over conventional dispersed hydrated sodium borate compositions and show good compatibility with additives typically used in fully formulated gear oil compositions. The finished oil compositions comprising such dispersed hydrated sodium borate compositions exhibit improved water tolerance with good storage stability.
This invention is also directed, in part, to methods for decreasing the turbidity of dispersed hydrated sodium borate compositions, and for improving the water tolerance of finished oil compositions comprising such dispersed hydrated sodium borate compositions.
REFERENCES
The following references are cited in this application as superscript numbers:
1
Peeler, U.S. Pat. No. 3,313,727, Alkali Metal Borate E.P. Lubricants, issued Apr. 11, 1967
2
Adams, U.S. Pat. No. 3,912,643, Lubricant Containing Neutralized Alkali Metal Borates, issued Oct. 14, 1975
3
Sims, U.S. Pat. No. 3,819,521, Lubricant Containing Dispersed Borate and a Polyol, issued Jun. 25, 1974
4
Adams, U.S. Pat. No. 3,853,772, Lubricant Containing Alkali Metal Borate Dispersed with a Mixture of Dispersants, issued Dec. 10, 1974
5
Adams, U.S. Pat. No. 3,997,454, Lubricant Containing Potassium Borate, issued Dec. 14, 1976
6
Adams, U.S. Pat. No. 4,089,790, Synergistic Combinations of Hydrated Potassium Borate, Antiwear Agents, and Organic Sulfide Antioxidants, issued May 16, 1978
7
Adams, U.S. Pat. No. 4,163,729, Synergistic Combinations of Hydrated Potassium Borate, Antiwear Agents, and Organic Sulfide Antioxidants, issued Aug. 7, 1979
8
Frost, U.S. Pat. No. 4,263,155, Lubricant Composition Containing an Alkali Metal Borate and a Sulfur-Containing Polyhydroxy Compound, U.S. Pat. No. 5,461,184, issued Oct. 24, 1995
9
Frost, U.S. Pat. No. 4,401,580, Lubricant Composition Containing an Alkali Metal Borate and an Ester-Polyol Compound, issued Aug. 30, 1983
10
Frost, U.S. Pat. No. 4,472,288, Lubricant Composition Containing an Alkali Metal Borate and an Oil-Soluble Amine Salt of a Phosphorus Compound, issued Sep. 18, 1984
11
Clark, U.S. Pat. No. 4,584,873, Automotive Friction Reducing Composition, issued Aug. 13, 1985
12
Brewster, U.S. Pat. No. 3,489,619, Heat Transfer and Quench Oil, issued Jan. 13, 1970.
All of the above references are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent was specifically and individually indicated to be incorporated by reference in its entirety.
STATE OF THE ART
High load conditions often occur in gear sets such as those used in automobile transmissions and differentials, pneumatic tools, gas compressors, centrifuges, high-pressure hydraulic systems, metal working and similar devices, as well as in many types of bearings. When employed in such environments, it is conventional to add an extreme-pressure (E.P.) agent to the lubricant composition and, in this regard, alkali metal borates are well known extreme-pressure agents for such compositions.
1-11
E.P. agents are added to lubricants to prevent destructive metal-to-metal contact in the lubrication of moving surfaces. While under normal conditions termed “hydrodynamic”, a film of lubricant is maintained between the relatively moving surfaces governed by lubricant parameters, and principally viscosity. However, when load is increased, clearance between the surfaces are reduced, or when speeds of moving surfaces are such that the film of oil cannot be maintained, the condition of “boundary lubrication” is reached; governed largely by the parameters of the contacting surfaces. At still more severe conditions significant destructive contact manifests itself in various forms such as welding, scoring, scuffing, ridging, rippling or cleavage. It is the role of E.P. additives to prevent this from happening. For the most part, E.P. agents have been oil soluble or easily dispersed as a stable dispersion in the oil, and largely have been organic compounds chemically reacted to contain sulfur, halogen (principally chlorine), phosphorous, carboxyl, or carboxylate salt groups which react with the metal surface under boundary lubrication conditions. Stable dispersions of hydrated metal borates have also been found to be effective as E.P. agents.
Because hydrated alkali metal borates are insoluble in lubricant oil media, it is necessary to incorporate the borate as a dispersion in the oil and homogenous dispersions are particularly desirable. The degree of formation of a homogenous dispersion can be correlated to the turbidity of the oil after addition of the hydrated alkali metal borate with higher turbidity correlating to less homogenous dispersions. In order to facilitate formation of such a homogenous dispersion, it is conventional to include a dispersant in such compositions. Examples of dispersants include lipophilic surface-active agents such as alkenyl succinimides or other nitrogen containing dispersants as well as alkenyl succinates.
1-4, 12
It is also conventional to employ the alkali metal borate at particle sizes of less than 1 micron in order to facilitate the formation of the homogenous dispersion.
11
Of the hydrated alkali metal borates heretofore used, hydrated potassium borates were conventionally employed. The hydrated potassium borate compositions, additive packages, and lubricant compositions comprising such borates often had unacceptably high turbidity when added to lubricant compositions.
In addition, the hydrated potassium borate compositions, additive packages and lubricant compositions comprising hydrated potassium borates often had poor water tolerance. Such intolerance was reflected by the formation of borate crystals that generally separate from the oil phase to form deposits that can damage the elastomer seals in various engine parts and cause leakage.
In view of the above, further reductions in turbidity and further improvements in water tolerance for oil compositions comprising a sodium borate would be particularly beneficial.
SUMMARY OF THE INVENTION
This invention is directed to the novel and unexpected discovery that the turbidity arising from the preparation of a dispersed hydrated sodium borate composition can be reduced by specifically controlling the degree of dehydration of the boron in the dispersion.
In addition, this invention is directed to the novel and unexpected discovery that the water tolerance of dispersed hydrated sodium borates is improved by carefully controlling the ratio of sodium to boron and the degree of dehydration in the composition.
Accordingly, in one of its composition aspects, this invention is directed to a dispersed hydrated sodium borate composition comprising a hydrated sodium borate, a dispersant, optionally a detergent, and an oil of lubricating viscosity wherein said hydrated sodium borate is characterized by a hydroxyl:boron ratio (OH:B) of from about 0.80:1 to 1.60:1 and by a sodium to boron ratio of from about 1:2.75 to 1:3.25.
In one preferred embodiment, the dispersed sodium borate compositions described herein have a turbidity of less than about 75 ntu, more preferably, less than about 60 ntu, and still more preferably, less than about 40 ntu.
In another preferred embodiment, the dispersed hydrated sodium borate composition has a sodium to boron metal ratio of from about 1:2.9 to about 1:3.1 and more preferably about 1:3.
In still another preferred embodiment, the hydroxyl:boron ratio is from about 0.90:1 to 1.50:1, more preferably 1.00:1 to 1.40:1.
In yet another preferred embodiment, the hydrated sodium borate has an average particle size of less than about 0.3 microns and more preferably from about 0.10 to about 0.20 microns.
Preferably, the dispersed sodium borate compositions contain small amounts of a water-soluble oxo anion. Only from 0.001 moles to 0.11 moles of water soluble oxo anion should be
Harrison James J.
Nelson Kenneth D.
Caroli Claude J.
Chevron Oronite Company LLC
Foley Joseph P.
McAvoy Ellen M.
LandOfFree
Dispersed hydrated sodium borate compositions having... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dispersed hydrated sodium borate compositions having..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dispersed hydrated sodium borate compositions having... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3070509