60/539,222 filed January 26,2004.

Technical Field The invention relates to the field of lubricant additives, and more particularly relates to the field of extreme pressure additives suitable for addition to engine oils and other lubricants.

Background Chlorine-based compounds, such as the chlorine derivates of paraffinic hydrocarbon compounds referred to as chlorinated paraffms, have long been used as lubricant additives to improve the performance of the lubricant under extreme pres- sure. In extreme pressure conditions, the liquid lubricant is forced from the area of contact between the two metal surfaces, but when an extreme pressure additive such as chlorinated paraffin is present, the heat generated between the two surfaces causes chlorine atoms to be liberated from the additive and to combine with the surface metal.

This causes a surface coating of a chloride, such as iron chloride, to be formed. This surface coating of chloride has a much lower coefficient of fiiction than the dry metal surface and fills in depressions in the surfaces, resulting in smoother surfaces at the point of contact and reduced friction and wear.

The use of chlorinated paraffins has various problems, including serious environmental problems such that products containing them are deemed unsuitable for safe disposal in the environment. The corrosive nature of chlorinated paraffins have made them generally unsuitable for use in internal combustion engine applications or other corrosion-sensitive applications. Under heating, the chlorinated paraffins release hydrochloric gas then subsequently hydrochloric acid, which is corrosive. They also are an irritant and harmful when in contact with skin. Chlorinated paraffins are thermally unstable and above 200°C degrade, generating strong acid radicals in the form of hydrogen chloride and free chloride ions. These radicals attack metal surfaces to form chloride films of the metal, which may lead to stress crack corrosion which

causes detriment to the structural materials, corrosion of bearings, piston and valve trains and eventual mechanical failure.

Phosphate esters have been known as a component of motor oils compositions.

See for example United States Patent no. 3,547, 820 Woodward et al. A problem with such formulations is avoiding hydrolysis of the base material as it encounters sustained high temperatures.

Summary of Invention The present invention provides an extreme pressure additive suitable for use in internal combustion engine lubricants or other applications where corrosion must be avoided.

According to one aspect of the invention, there is provided an extreme pressure lubricant additive comprising between 50% and 70% and preferably about 65.915 % of a motor oil; between 12% and 20% and preferably about 16 % of a phosphate ester such as Crodaphos C05A ; between 5% and 20% and preferably about 12.5 % of an aromatic antistatic solvent such as Solvesso 100; between. 2% and 1.5% and preferably about 0.897 % Calcium Sulphonate; between. 01% and. 9% and preferably about. 688 % of a butylated hydroxytoluene such as Topanol O ; and between 0% and 6% and preferably about 4% Triethanolamine. Thus the invention provides an extreme pressure lubricant additive consisting essentially of : (a) approximately 65.9 volume percent motor oil; (b) approximately 16 volume percent phosphate ester; (c) approxi- mately 12.5 volume percent of an aromatic solvent; (d) approximately. 9 volume percent of an alkaline earth metal sulphonate; (e) approximately. 7 volume percent of an anti-oxidant such as butylated hydroxytoluene; and (f) approximately 4 volume percent of Triethanolamine.

Further according to the invention there is provided a method of producing an extreme pressure additive for lubricants comprising the steps of a) pre-heating the phosphate ester (e. g. Crodophos C05A) to 34 degrees C.; b) pre-mixing Solvesso and Topanol until dissolved and premix with Crodaphos C05A ;

c) add calcium sulphonate to b); d) adding triethanolamine 100% preheated to 35 degrees C to base oil and stirring; e) stir for at least 20 minutes then add the premixed SOLVESSO and TOPANOL f) Stir for 30 minutes to give a clear pale yellow viscous liquid.

Description Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention.

Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

Phosphate esters in general are non-classified and are considered safe to handle compounds. They do not possess the unpleasant characteristics of the chlorinated paraffins. Initially when the phosphate esters were first developed, hydrolysis was a constant problem and thermal stability was another. This has been overcome by the use of combinations of oelyl and cetyl alcohol derivatives which are esterified to form acid esters. These require neutralising utilising a safe but suitable element or com- pound. The molecule of water generated by condensation is incorporated by the ethoxylated ester and is released slowly over time.

The main distinct advantages of the new generation of phosphate esters are their thermal stability, slow degradation and where there is any formation of a phos- phate acid radical, metal surfaces are coated on a mono-molecular basis to self inhibit further chemical interaction. The coating lends itself to increased absorption of extreme pressure additive thus further enhancing the performance of the phosphate ester. Thus the use of phosphate esters is non-corrosive towards metal surfaces as an extreme pressure additive and is more environmentally friendly than chlor paraffins.

In the case of chlor paraffins, if engine oil containing this material is not changed on time then severe damage will result to bearings and all moving parts of the engine whereas with a phosphate ester compound this does not occur. The phosphate

ester systems are environmentally approved due to their safety and non- bioaccumulation. Disposal of products containing this type of extreme pressure additive is safe and no regulatory information is required for disposal.

The preferred form of additive according to the invention has the following composition (percentages are shown by volume): 65.915 % base motor oil, such as Castrol E20 motor oil 16 % Crodaphos C05A 12.5 % anti-static solvent such as Solvesso 100 0. 897 % Calcium Sulphonate 0.688 % anti-oxidant such as butylated hydroxytoluene ; Topanol O 4% Triethanolamine.

The composition will also work within the following approximate ranges: between 50% and 70% and preferably about 65.915 % of a motor oil; between 12% and 20% and preferably about 16 % of a phosphate ester such as Crodaphos C05A ; between 5% and 20% and preferably about 12.5 % of an aromatic antistatic solvent such as Solvesso 100; between. 2% and 1.5% and preferably about 0.897 % Calcium Sulphonate; between. 01% and. 9% and preferably about. 688 % of a butylated hydroxytoluene such as Topanol O ; and between 0% and 6% and preferably about 4% Triethanolamine.

The following method is used to produce the extreme pressure additive. First the base motor oil is added to the mixing container. The Crodaphos C05A is pre- heated to 34 degrees Centigrade. The Solvesso and Topanol are then pre-mixed until dissolved and are then premixed with the Crodaphos C05A. The calcium sulphonate is added to the pre-mixed Solvesso, Topanol and Crodaphos. The Triethanolamine 100% is preheated to 35 degrees C and added to the base oil and mixed, such as by stirring for at least 20 minutes, and the pre-mixed calcium sulphonate, Solvesso, Topanol and Crodaphos is then added. The final mixture is then mixed such as by stirring for 30 minutes to give a clear pale yellow viscous liquid. The result of this final blending process is the extreme pressure additive of the invention.

The final product is used by adding it to the motor engine oil preferably in a 5% to 10% proportion. In addition to serving as an extreme pressure additive for motor

oils, the lubricant additive of the invention may also be added to other lubricants and fluids such as greases (where a proportion of approximately 4% to 12% by volume of the additive is preferred), metal cutting lubricants, industrial gear lubricants, hydraulic oils (excluding hydraulic brake fluid), automatic transmission fluid, power steering fluid, penetrating oil, air conditioner refrigerant, and as a coating for brass. In all these applications, the additive of the invention serves to reduce friction and metal wear under extreme pressure situations, and also serves to reduce corrosion. It has also been found that by adding the extreme pressure additive product of the invention to a gasoline or diesel fuel conditioner, the performance of the internal combustion engine may be improved through lubrication of the moving metal parts which come into contact with the fuel in the upper end of the engine.

The main advantages of the new ester system is that even during hydrolysis, if this should occur, the acid radical developed will be the acid phosphate ion which produces a tenacious phosphate film on ferrous surfaces which, in turn, generates a protective film. This attracts more extreme pressure additive onto the surface, acting as a sponge to absorb the base materials. Unlike chlor paraffins which release acid radicals which are extremely corrosive and damage ferrous and non-ferrous surfaces, the phosphate system does not cause damage and thereby, when the phosphate film is formed, creates a protective coating on the metal surface thereby inhibiting any further attack. If the engine oil is not changed on time it is likely that corrosive elements will be formed but due to the nature of the phosphate ion, no further chemical damage will be done to engine parts.

While Crodaphos C05A has been specified as the appropriate phosphate ester, other phosphate esters having similar properties would also be suitable for use in the invention. While calcium sulfonate has been specified as the appropriate sulfonate other alkaline earth metal sulfonates having similar properties, such as barium sulfonate, would also be suitable for use in the invention. While Solvesso 100 has been specified as the appropriate anti-static solvent, other solvents having similar proper- ties, would also be suitable for use in the invention. While Topanol O has been specified as the appropriate butylated hydroxytoluene, other butylated hydroxytoluenes having similar properties would also be suitable for use in the invention. Thus while a preferred embodiment of the invention has been described, the scope of the invention should not be limited thereto.

As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims