Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Compound of indeterminate structure – prepared by reacting an...
Reexamination Certificate
2002-04-02
2003-04-15
Howard, Jacqueline V. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Compound of indeterminate structure, prepared by reacting an...
C508S458000, C252S396000, C560S184000, C560S188000
Reexamination Certificate
active
06548459
ABSTRACT:
This application claims priority from and incorporates by reference Indian Patent Application No. 846/Mum/2001, filed Sep. 3, 2001.
BACKGROUND
Cashew nut shell liquid (CNSL) occurs as a reddish brown viscous liquid in the soft honeycomb structure of the shell of cashewnut, a plantation product obtained from the cashew tree, Anacardium Occidentale L. Native to Brazil, the tree grows in the coastal areas of Asia & Africa. Cashewnut attached to cashew apple is grey colored, kidney shaped and 2.5-4 cm long. The shell is about 0.3 cm thick, having a soft leathery outer skin and a thin hard inner skin. Between these skins is the honeycomb structure containing the phenolic material popularly called CNSL. Inside the shell is the kernel wrapped in a thin brown skin, known as the testa.
The nut thus consists of the kernel (20-25%), the shell liquid (20-25%) and the testa (2%), the rest being the shell. CNSL, extracted with low boiling petroleum ether, contains about 90% anacardic acid and about 10% cardol. CNSL, on distillation, gives the pale yellow phenolic derivatives, which are a mixture of biodegradable unsaturated m-alkylphenols, including cardanol. Catalytic hydrogenation of these phenols gives a white waxy material, predominantly rich in tetrahydroanacardol.
CNSL and its derivatives have been known for producing high temperature phenolic resins and friction elements, as exemplified in U.S. Pat. Nos. 4,395,498 and 5,218,038. Friction lining production from CNSL is also reported in U.S. Pat. No. 5,433,774. Likewise, it is also known to form different types of friction materials, mainly for use in brake lining system of automobiles and coating resins from CNSL. However, the first application of CNSL in making lubricating oil additives was disclosed by us in U.S. Pat. Nos. 5,916,850 and 5,910,468.
The general term to describe the moisture corrosion is rusting. Rusting is caused by electrochemical attack of oxygen through water on the ferrous metal surfaces of the gear. The rusting is greatly aggravated by the presence of sulphur and phosphorus compounds (EP & AW additives) and their thermal, oxidation or hydrolytic decomposition by-products. A good automotive or industrial gear oil should have ample rust preventive characteristics built-in to combat all eventualities.
Rust is the common oxidative corrosion on iron and its alloys and is the result of an electrochemical reaction. A great deal of research to develop means of controlling or eliminating rust has been conducted. Strategies to control the rust include eliminating oxygen or preventing the electrolyte and oxygen from interacting at the metal surface, the conditions not practically possible, or by the use of polar compounds known as rust inhibitors.
Rust inhibitors are generally surface active agents consisting of polar compounds. The structure of these polar compounds consists of a “head” which has a strong affinity for the metal surface and a hydrocarbon “tail” which orients itself away from the surface. These molecules form a tightly adsorbed monolayer, which prevents moisture and oxygen from reaching the metal surface. Common Chemistries of the polar head of these molecules include—Carboxylic acids, their esters, sulphonates, imidazolines, amines etc., performance of each class of the rust inhibitor depends upon:
Type of the other additives present in the system
Service conditions
Metallurgy type to be protected
An exhaustive literature review was conducted to examine the types of Chemistries in use for selection of the rust inhibitors for use in blending modern grades of gear lubricants. There was hardly any published literature correlating the performance of a RI with its Chemistry. However, there are a sizable number of patent references for development of rust inhibiting additives for gear oil applications. These include U.S. Pat. No. 6,180,575 (Jan, 2001. Mobil) for mixture of substituted benzotriazole and amine phosphates, U.S. Pat. No. 6,165,952 (Dec, 2000. Kings Industries) for mixture of condensed polyacids and amines, U.S. Pat. No. 5,358,650 (Oct, 1994. Ethyl) mixtures of aminosuccinic esters and dimer acids, U.S. Pat. No. 4,247,414 (Jan, 1981, Nippon), mixtures of alkylphenoxy ethyleneglycol and phosphate esters. Other patents which describe corrosion inhibiting compositions of gear oils include U.S. Pat. No. 5,055,230 (Oct, 1991, Ciba-Geigy), U.S. Pat. No. 4,493,776 (Jan, 1985, Shell) U.S. Pat. No. 4,427,565 (Jan, 1984, Standard Oil), U.S. Pat. No. 5,487,846 (Jan, 1996, Union Chemicals) and U.S. Pat. No. 3,909,215 (Sept, 1975, Chevron).
Literature review revealed that a large number of additives with different chemistries have been developed and used in gear oil compositions. Also, it has become increasingly evident that for passing CRC L-33 corrosion test, a combination of additives had to be used. This makes sense as L-33 rig contains parts having different metallurgies, i.e., cover plates, pinion and gears and the effective RI should be able to protect all these parts which count in the corrosion rating.
The present invention relates to lubricant compositions and more particularly, to lubricant compositions comprising oils of lubricating viscosity or greases thereof containing a minor rust inhibiting additive of alkyl phenoxy carboxylic acids and their esters or amides derived from cashew nut shell liquid.
Recently, our U.S. Pat. No. 5,916,850 described development of multifunctional additives from cashew nut shell liquid or from saturated alkylphenols derived from cashew nut shell liquid. The patent relates to a process for preparing di(alkylaryl)phosphorodithioate. The products of this invention were found to have better antifriction, extreme pressure and antiwear properties. In another U.S. Pat. No. 5,910,468, cashew nut shell liquid has been exploited for developing overbased calcium phenate detergents as additives for lubricant formulations.
The object of the present invention is to provide for a rust inhibiting alkyl phenoxy acetic acid/ester based lubricant/fuel additive, derived from CNSL, a renewable and biodegradable product from vegetable sources and often available at very low price, which would amount to substantial overall reduction in the cost of quality, energy efficient lubricant/fuel formulations.
Another object of the present invention is to provide for a lubricant composition and more particularly, to lubricant compositions comprising oils of lubricating viscosity or greases thereof containing a minor rust inhibiting additive derived from alkyl phenoxy acetic acid/ester derived from cashew nut shell liquid.
DETAILED DESCRIPTION OF THE INVENTION
To achieve the said objects, the present invention provides a process for the preparation of alkyl phenoxy carboxylic acid/ester for use as an additive in a lubricant composition by reacting said cashew nut shell liquid with halo carboxylic acid or ethyl chloroacetate to obtain corresponding unpolymerized cashew nut shell liquid alkyl phenoxy carboxylic acid/ester, the reaction being carried out at a temperature ranging from 20 to 140° C. Alternatively, rust inhibitor can be synthesized by first hydrogenating distilled technical cashew nut shell liquid (CNSL) with a catalyst as herein described to fully hydrogenate the olefinic chain and reacting said cashew nut shell liquid with halo carboxylic acid or ethyl chloroacetate to obtain corresponding unpolymerized cashew nut shell liquid alkyl phenoxy carboxylic acid/ester.
The Carboxylic acids required to produce the additive compositions of the present invention have 1 to 3 carboxyl based groups, and contain a halogen substituted hydrocarbon based aliphatic or alicyclic group that is, a group having a halogen atom attached directly to an aliphatic or alicyclic carbon atom, i.e., a carbon atom that is part of an aliphatic or alicyclic based group. The halogen atom in these carboxylic acid reagents is preferably chlorine or bromine. More preferably, the chlorine or bromine atom is bonded to a carbon alpha to at least one of the carboxyl based groups present.
Carboxyl based groups include free carboxy
Bhatnagar Akhilesh Kumar
Dohhen Khem Chand
Mondal Pankaj Kumar
Raje Niranjan Raghunath
Sarin Rakesh
Howard Jacqueline V.
Indian Oil Corporation Limited
Sidley Austin Brown & Wood LLP
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