Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Inorganic compound
Reexamination Certificate
1998-11-09
2001-01-09
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Inorganic compound
C508S345000, C508S378000, C508S535000
Reexamination Certificate
active
06172012
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to titanium complex grease compositions having performance additives and to a process and compositions thereof. The additives envisaged by the present invention include anti-oxidants, extreme pressure and antiwear additives, rust inhibitors, friction modifiers, structural modifiers, polymers, solid lubricants, biodegradable additives/ashless additives, multifunctional additives etc.
2. Description of the Related Art
In prior art, the concept of thickening oils by soaps for lubrication purpose is well known. The usage of metallic soaps or their complex soaps as thickeners still dominates in lubricating greases. These metallic or complex metallic soap base greases are generally derived from metals such as lithium, calcium, sodium, barium, aluminum etc. Lithium base greases are mainly used, and probably for their better performance, easily availability and cost factors etc. Metallic soaps based on other metals have also been reported in prior art (C. J. Boner, Ind. Eng. Chem, 29, 59, 1937). However such metallic soaps did not have advantageous application in lubricating greases.
Such commercially used greases are associated with one or other disadvantages and are not able to meet fully the various requirements of modern machinery. For instance, most widely used lithium base greases use LioH but the restricted availability of lithium constitutes a disadvantage. Further, lithium has questionable toxicity (NLGI Spokesman, Apr. 1994). These greases require addition of certain performance additives which are costly and many of them are environmentally unsafe. The manufacture of such greases required large quantities of vegetable fats, which otherwise could have been used for edible and other industrial applications.
U.S. Pat. No. 5,387,351 in the name of the present applicants describes a lubricating grease composition based on titanium complex soap thickeners. Specifically, the lubricating grease composition of the aforesaid U.S. patent comprises 2 to 20% by weight of titanium alkoxide, 2 to 20% by weight of carboxylic additives acids, 5.0 to 35.0% by weight of fatty acids, 0 to 5.0% by weight of water and 20 to 90% by weight of oil selected from mineral and synthetic oil.
A primary object of this invention is to propose Ti-complex grease compositions incorporating certain performance additives and to a process for the preparation thereof.
Another object of this invention is to propose a Ti-complex grease composition incorporating performance additives with improved wild properties.
Still another object of this invention is to propose novel lubricating grease compositions with improved extreme pressure, anti, wear, antioxidant, rust and corrosion inhibition and frictional properties.
SUMMARY OF THE INVENTION
According to the invention there is provided a lubricating grease composition comprising b
2
to 20% by weight of titanium alkoxide, 2 to 20% by weight of carboxylic acid, 5.0 to 35.0% by weight of fatty acids, 0.0 to 5.0% by weight of water and 20 to 90% by weight an oil selected from mineral and synthetic oil and 0.01 to 50% of performance additives.
In accordance with a preferred embodiment of this invention the lubricating grease composition 2 to 20% by weight of titanium alkoxide, 5 to 25% by weight of fatty acid, 2 to 20% by weight of carboxylic acid, 0.0 to 5.0% by weight of water and 20 to 90% by weight of oil selected from mineral and synthetic oil, and said performance additives.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The performance additives are selected from the following additives and present singularly or in any combination.
TABLE 1
S.NO.
CLASS OF ADITIVIES
1.
Extreme pressure
2.
Antiwear additives
3.
Antioxidant
4.
Anti rust/ corrosion inhibitors
5.
Friction modifiers
6.
Structure modifiers/tackifier
7.
Solid lubricants
8.
Multifunctional additives
9.
Biodegradable additives
Further according to this invention there is provided a process for the preparation of lubricating grease composition which comprises in the step of forming in a first stage a mix by adding together 2 to 20% fatty acid, 2 to 20% carboxylic acid and 20 to 90% by weight of mineral or synthetic oil stirring and heating such a mix to a temperature of 70 to 100° C., adding in a second stage 2 to 20% by weight of titanium alkoxide while maintaining said temperature, raising the temperature to 100° C. to 200° C. to form a thickened grease product, cooling said product, and in a third stage adding 0 to 5% by weight of water thereto, if required, and then subjecting the mixture to the step of shearing, adding performance additives at 160-60° C. while cooling followed by homogenising/milling to obtain said composition.
In accordance with this invention, a vessel equipped with a stirrer or rpm 0-150 in the first stage, is charged with 5 to 35% by weight of fatty acid, 2 to 20% by weight of carboxylic acid and 20 to 90% by weight of mineral or synthetic oil, based on the total weight of the final grease composition.
The mixture is stirred and heat is provided through a heating mantle to reach the temperature to 70-100° C. At the end of the first stage, 2 to 20% by weight of titanium alkoxide is added slowly based on the total weight of the final grease composition.
The mixture is continuously mixed and held at 70-100° C. for 1-2 hour, temperature being raised very slowly to 100-200° C., duration of maintaining at this temperature is 2-8 hours. During this period the product assumes grease structure and converts to a thickened mass. The product is then cooled with continuous stirring to 140-100° C. at the end of this second stage, if desired up to 5% by weight of water is added to the mixture, based on the total weight of the final grease composition. The mixture is further cooled to 80-60° C. sheared with the help of a colloid mill adding said additives while cooling and followed by homogenizing and milling.
It is, however, possible to combine the first and second stages to provide an alternate route.
Thus, according to this invention there is provided an alternate process for the preparation of a lubricating grease composition which comprises in preparing in the first stage a mix by adding together fatty acid, carboxylic acid, titanium alkoxide and mineral or synthetic oil in required proportions, heating such a mixture to a temperature of 160 to 200° C. adding said additives at a temperature of 140 to 160° C. while cooling and then subjecting the composition to the step of homogenization and milling.
In accordance with the alternate process of this invention, the charge is stirred with simultaneous heating through a heating mantle. The mixture is heated upto a temperature of 160-200° C. in 2-8 hours. The resultant product is cooled to 140-80° C. and water is added from 0.1 to 5.0%. This is further stirred for 5 minutes to 1 hour at this temperature and then further cooled to 80-50° C. and sheared in a colloid mill.
Titanium alkoxide used in present invention is preferably titanium alkoxide of C3 to C6 alcohol having titanium metal content of 17% by weight approximately and used in the amount 2-20% by weight of the final lubricating grease composition. The synthetic hydrocarbon lubricating oil used in the compositions of present invention is an oligomer of olefin such as polyalpha olefins, polybutenes, polyethers, mineral base stocks are the neutral oils.
The sources of fatty acids employed in the grease composition are alkyl carboxylic acids from vegetable and animal source which may have few double bonds in the structure. For instance, it includes stearic acid, hydroxystearic acid, oleic acid, mahuwa oil, etc. and present in an amount of 5 to 35% by weight of the final lubricating grease composition.
The carboxylic acids employed in this invention invention are, for example, mono-carboxylic acid ranging from acetic acid to BVC acid, C2 to C10 carbon chain dicarboxylic acids, hydroxydicarboxylic acids such as tartaric acids and citric acid, aromatic acids include mono and dicarboxylic acids both, as well as hydroxy m
Bhatnagar Akhilesh Kumar
Kumar Anoop
Nagar S. C.
Naithani Kanta Prasad
Rai M. M.
Indian Oil Corporation Limited
McAvoy Ellen M.
Spencer George H.
Venable
Wells Ashley J.
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