Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic phosphorus compound – wherein the phosphorus is...
Reexamination Certificate
2001-03-30
2003-10-28
Johnson, Jerry D. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic phosphorus compound, wherein the phosphorus is...
C508S112000, C508S353000, C508S429000
Reexamination Certificate
active
06638898
ABSTRACT:
This invention relates a process for preparing multi-functional additive for lubricant composition from saturated cashew nut shell liquid. The said additive for use in a lubricant, imparts suitable properties of friction reducing, antioxidant, antiwear and extreme pressure additives.
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.
Friction is also a problem any time two surfaces are in sliding or rubbing contact. It is of special significance in an internal combustion engine and related power train components, because loss of a substantial amount of the theoretical mileage from a gallon of fuel is traceable directly to friction.
It is also known that sliding or rubbing metal or other solid surfaces are subject to wear under conditions of extreme pressure. Wear is particularly acute in modern engines in which high temperatures and contact pressures are prevalent. Under such conditions, severe erosion of metal surfaces can take place even with present generation lubricants unless a load carrying or antiwear additive is present therein. These load carrying, friction reducing, antiwear and antioxidant additives are generally organic compounds, having polar groups, which are capable of forming a film at the mating metal surfaces.
Considerable work has been reported with lubricating oils, mineral and synthetic, to enhance their antioxidant, antiwear and friction reducing properties, by modifying them with suitable additives. The use of lubricant additives containing phosphorus and sulfur has been well documented and widely implemented commercially. These include acid phosphates, thiophosphates, phosphites, phosphate ester, metal dithiophosphates, metal dithiocarbamates, xanthates, phosphonates and the like. Amine compositions have also found wide use as friction reducing additives as exemplified by U.S. Pat. No. 4,328,113 which relates to alkyl amines and diamines and borated adducts of alkylamine and diamines. U.S. Pat. No. 4,478,732 describes imidazoline salts of acid phosphates, while U.S. Pat. No. 4,505,830 is drawn to C
10
-C
20
alkyl substituted imidazoline salts of boric acid or phosphoric acid as useful in metal working lubricants. U.S. Pat. No. 4,618,437 describes boronated internal imidazoline acid phosphates as effective friction reducers.
The present invention relates to lubricant compositions and more particularly, to lubricant compositions comprising oils of lubricating viscosity or greases thereof containing a minor friction reducing, antiwear and antioxidant additive of hydrocarbyl amine salt of di(alkylcyclohexyl)phosphorodithioic acid 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 antifriction, extreme pressure and antiwear properties.
The object of the present invention is to provide for a multifunctional lubricant/fuel additives, derived from CNSL, a renewable and biodegradable product from vegetable sources and often available at very low price, 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 friction reducing, antiwear and antioxidant additive of hydrocarbyl amine salt of di(alkylcyclohexyl)phosphorodithioic acid derived from cashew nut shell liquid.
SUMMARY OF THE INVENTION
To achieve the said object the present invention provides a process for the preparation of multi-functional additive, amino di(alkylcyclohexyl) phosphorodithioate, for use as an additive in a lubricant composition comprising the steps of hydrogenating distilled technical cashew nut shell liquid (CNSL) with a catalyst as herein described to fully hydrogenate the olefinic chain and aromatic ring of the precursor and obtain fully saturated CNSL; reacting said fully saturated cashew nut shell liquid with phosphorus pentasulfide to obtain corresponding unpolymerized cashew nut shell liquid phosphorodithioic acid, the reaction being carried out at a temperature ranging from 20 to 140° C.; and condensing the unpolymerized cashew nut shell liquid phosphorodithioic acid with at least one amine to obtain the amino di(alkylcyclohexyl) phosphorodithioate.
The said catalyst is palladium, platinum or nickel.
At least one amine is selected from the group consisting of primary, secondary and tertiary alkyl/alkylaryl amines having an all chain ranging from C
1
to C
20
. At least one amine is a mixture of amines selected from the group consisting of primary, secondary and tertiary alkyl and alkylaryl amines and alkylaryl amines having an alkyl chain ranging from C
1
to C
20
.
Preferred secondary amines includes dipentylamine, dihexylamine, dicyclohexylanine, bis(2-ethylhexyl)amine, dioctylamine, dinonylamine, didodecylamine.
Preferred primary amines includes oleyl amine, stearyl amine, isostearyl amine, cocoamine, tallow amine, hydrogenated tallow amine, t-alkylamines, diethanolamine, dodecylamine, decylamine, octylamine, 2-ethylhexylamine and butylamine.
Preferred tertiary amines includes triethylamine, tributylamine, triethanol amine. Suitable diamines include diethylenetriamine, triethylenetetramine, N-coco-1,3-propylenediamine, N-oleyl-1.3-propylene diamine.
Generally amines having at least 2 to 4 and up to 24 to 26 carbon atoms including mixtures of such amines have been found to be highly useful in this invention.
The reacting and the condensation steps are carried out in the presence of a solvent.
At least one amine and the phosphorodithioic acid are present in stoichiometric ratios of acid to amine ranging from about 3:1 to about 1:3, preferably from 2:1 to 1:2.
The present invention further includes a lubricant composition comprising a major proportion of a material selected from the group consisting of an oil of lubricating viscosity and a grease and remainder an additive comprising amino di(alkylcyclohexyl)phosphorodithioate which is a condensation product of unpolymerized cashew nut shell liquid phosphorodithioic acid with at least one amine.
The additive is present in an amount ranging from about 0.1 to about 10 wt %, preferably 0.5 to 5 wt %.
The oil of lubricating viscosity is selected from the group consisting of a mineral oil, a syntheti
Bhatnagar Akhilesh Kumar
Parkash Shanti
Sarin Rakesh
Swami Krishan Kumar
Tuli Deepak Kumar
Indian Oil Corporation Limited
Johnson Jerry D.
Sidley Austin Brown & Wood LLP
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