FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Bio-based Gear Oil and Process of Preparation Thereof
2. APPLICANT
(a) NAME: Mint Agri Research & Development Pvt Ltd
(b) NATIONALITY: Indian Company
(c) ADDRESS: Mint Biofuels Limited
S.No. 1073/1,2,3,
Mutha Road, Pirangut, Pune - 412 111
3. PRREAMBLE TO THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Bio-based Gear Oil and Process of Preparation Thereof
Field of the invention
The present invention relates to gear oil, and more particularly, to a highly lubricant, non-toxic, polar and biodegradable vegetable oil based lubricating oil for gear boxes and a process for the preparation thereof.
Background of the invention
Gear box is a device used to transfer required power at required speed to driven machine or mechanism from drive such as electric motor or oil engine. The gear boxes have different designs and mechanisms such as worm and worm wheel, spur, helical, planetary and like. The gear mechanism of all of them are embedded in a sump filled with gear oil so that the required power transfer is through liquid medium instead of direct contact of mechanical means. The liquid medium reduces the friction and transfers the power with minimum losses due to friction. In any type of gear box, for transferring power at high efficiency, it is necessary to use oil medium between contact surfaces of gears. If the oil medium is not used then the mechanical contacts will have high friction resulting in power loss, much reduced life and results in raising the temperature of gears to high level, causing noise and vibrations.
Depending on the construction of gear box such as worm and worm wheel, spur, helical, planetary and like as well as the quantum of power transfer with ratio of speed or RPM (revolutions/min) between a drive and driven mechanism, the liquid medium called as gear oil is selected. The principal requirements of the gear oil are lubricity, viscosity, viscosity index, pressure withstanding capacity and shear strength for specific applications. Depending on these qualities of the gear oil and the construction of the gears there is still loss of power causing heating, noise, vibrations and loss of efficiency of the gear box as well as its own life.

Friction, oil churning and seal drag account for most of the losses in gear box resulting into heat or rise in temperature, noise and vibrations. The frictional loss depends on lubricity. Oil churning is caused due to components moving through the oil sump. Hence churning losses are a function of viscosity. Thus thicker oil or viscous oil requires more energy to move the gears and the bearing rollers in the oil sump. The viscosity is selected depending on the lubricity and pressure withstanding capacity related to total power transfer. Noise and vibrations also depend on the lubricity and viscosity.
It is observed that, the gear box efficiency is a concern while designing any machine or mechanism. The overall efficiency of power transfer varies from 60% to 95% depending on type of gear box and selection of gear oil. Another concern is of evaporation of the gear oil due to high temperature rise that requires frequent top-up and consumption of oil. Moreover, vaporization of oil or its disposal after use can cause environmental pollution.
The gear oils used are either petroleum based or synthetic in nature. The petroleum based lubricants exhibit lowest lubricity and efficiency for the gear box followed by synthetic lubricants causing frictional losses and heat, resulting in rise in temperature and evaporation of oil. Also, the petroleum based lubricants have lower viscosity index followed by the synthetic lubricants, thus requiring high viscosity of oil at ambient temperature. This causes churning losses in addition to frictional loss. Both together also cause noise and vibrations. In addition, the petroleum based lubricants are not biodegradable and disposal of the gear oils either mineral based or synthetic is a critical issue. The evaporation of mineral based or synthetic gear oil also causes air pollution. Overall both types of gear oils cause energy loss to the extent of 20%, reduce life of the gear box and require frequent top-up or change of gear oil.

Accordingly, there exists a need of a highly lubricant, non-toxic and biodegradable vegetable oil based lubricating oil for gear boxes that overcomes the drawbacks of the prior art.
Objects of the invention
An object of the present invention is to provide a highly lubricant, non-toxic, polar and biodegradable bio-based gear oil having superior lubricity and thin film strength leading to higher efficiency and energy saving of the gear box.
Another object of the present invention is to provide long life for the gear mechanism.
Yet another object of the present invention is to provide bio-based gear oil having high viscosity index requiring lower viscosity in normal room temperature as well as during operation and low evaporation rate so that, top-up requirement will be reduced.
One more object of the present invention is to provide a process for preparation of a bio-based, biodegradable, non-toxic gear oil that provides superior lubricity and thin film strength.
Summary of the invention
Accordingly, the present invention provides a bio-based gear oil formulation having superior lubricity and thin film strength. The bio-based gear oil formulation comprises a polyol ester of vegetable oil in a range of 78% by weight to 90 % by weight. Further, the bio-based gear oil formulation comprises polyalfaolefins of grade 100 in a range of 10 % by weight to 20 % by weight. Furthermore, the bio-based gear

oil formulation comprises an antioxidant, for example di-tert-butyl-p-cresol, in a range of 0.1 % by weight to 0.3 % by weight.
In another aspect, the present invention discloses a process of the preparation of the bio-based gear oil formulations having superior lubricity and thin film strength.
Brief description of the drawings
Figure 1 shows a flowchart for a process of preparation of a bio-based gear oil formulation, in accordance with the present invention.
Detailed description of the invention
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
Accordingly, the present invention provides a bio-based, highly lubricant, polar, biodegradable, non-toxic lubricating oil formulation for gear oils. The lubricating oil formulation of the present invention has high viscosity index, high flash point and low evaporation rate. In another aspect, the present invention provides a process for the preparation of the formulation of the gear oil.
In accordance with the present invention, the vegetable oil is selected based on the fatty acid profile having minimal presence of the un-saturation that results in high lubricity, excellent thermal and oxidative stability as well as other desired qualities. The base oil selection from any one of Elaeis guineertsis seed oil. Pongamia pinnata oil and mustard oil provides the qualitative superiority of desired qualities as per requirements of application. For example, the lubricity of mustard is higher than that of Elaeis guineensis.

The present invention provides a bio-based, lubricating gear oil (hereinafter 'the bio-based gear oil"). The bio-based gear oil formulation comprises a polyol ester of vegetable oil in a range of 88 % by weight to 90 % by weight. The examples of vegetable oil include Elaeis guineensis seed oil, Pongamia pinnata and mustard oil. Further, the bio-based gear oil formulation 1 comprises polyalfaolefins of grade 100 in a range of 10 % by weight to 12 % by weight. Furthermore, the bio-based gear oil formulation 1 comprises an antioxidant, for example di-tert-butyl-p-cresol, in a range of 0.1 % by weight to 0.3 % by weight. In accordance with the present invention, the bio-based gear oil formulation 1 posses 68 grade viscosity.
In an embodiment, the present invention provides a bio-based, lubricating gear oil (hereinafter 'the bio-based gear oil formulation 2'). The bio-based gear oil formulation 2'comprises a polyol ester of vegetable oil in a range of 78% by weight to 80 % by weight. The examples of vegetable oil include Elaeis guineensis seed oil, Pongamia pinnata and mustard oil. Further, the bio-based gear oil formulation 2 comprises polyalfaolefms of grade 100 in a range of 18 % by weight to 20 % by weight. Furthermore, the bio-based gear oil formulation 2 comprises an antioxidant, for example di-tert-butyl-p-cresol, in a range of 0.1 % by weight to 03 % by weight. In accordance with the present invention, the bio-based gear oil formulation 2 posses 90 grade viscosity.
In yet another aspect, the present invention provides a process (100) for preparation of a bio-based gear oil as illustrated in figure 1.
The process (100) starts at (10). At step (20), the process (200) includes preparing a methyl ester of a vegetable seed oil, by esterification and trans-esterification process using saturated triglycerides preferably in a concentration of about 40 % by weight to 55 % by weight. The examples of the vegetable oil include Elaeis guineensis seed oil, Pongamia pinnata seed oil, mustard oil and combinations thereof. In an embodiment,

the vegetable seed oil is selected having free fatty acids content less than 15%, the methyl ester is selected having ester content of minimum 96.5% and acid value of 0.05 mg KOH/g maximum.
At step (30), the process (100) includes adding trimethylol propane to the methyl ester in presence of an alkaline catalyst, for example, sodium methoxide, under a predefined vacuum and temperature thereby converting the methyl ester into a polyol ester. In an embodiment, the vacuum is 1 torr or less and the temperature is about 130° C.
At step (40), the process (100) includes blending the polyol ester of the vegetable seed oil with polyalfaolefins in a predefined proportion to form a mixture. In an embodiment, the polyalfaolefins is of 100 grade. However, it is, understood that other grades of polyalfaolefins can be used for alternative embodiments of the bio-based gear oil formulation.
At step (50), the process (100) includes adding an antioxidant to the mixture to enhance the oxidative stability of the formulations. In an embodiment, the antioxidant is di-tert-butyl-p-cresol. The process (100) ends at step (60).
The invention is further illustrated hereinafter by means of examples.
Example 1: Preparation of an acid catalyst mixture
The acid catalyst mixture was prepared by dissolving about 0.7 gm to 0.8 gm of concentrated sulphuric acid in about 32 gm to 36 gm of methanol. Acid catalyst mixture was prepared at ambient temperature.
Example 2: Preparation of a base catalyst mixture

The base catalyst mixture was prepared by dissolving about 1.3 gm to 1.4 gm of potassium hydroxide in about 20 gm to 25 gm of methanol. Base catalyst mixture was prepared at ambient temperature.
Example 3: Preparation of methyl esters of vegetable seed oil by esterification
In this process, free fatty acids of the vegetable seed oil were converted into a methyl ester. For converting free fatty acid of the vegetable seed oil to the methyl ester, acid catalyst mixture was slowly added to about 100 gm of vegetable seed oil at 60° C in a reactor within 15 minutes to 20 minutes to form a reaction mixture. The reaction mixture was kept under stirring for about 80 minutes to 90 minutes. Acid layer was removed by transferring the reaction mass to a settler and allowed to settle for about 30 minute to 45 raiimtes at ambient temperature and pressure. During setting period phase separation occurs and top layer of acid-methanol mixture and bottom layer of acid esterified vegetable seed oil were formed. The top layer of acid-methanol mixture was sent for distillation for methanol recovery. The bottom layer of acid esterified vegetable seed oil layer was purified by filtration and dried to form vegetable seed oil methyl ester. Further, the bottom layer of acid esterified vegetable seed oil layer was transferred to a separate reactor for transesterification process.
Example 4: Preparation of methyl esters of vegetable seed oil by transesterification
In this process, triglycerides of vegetable seed oil were converted into methyl ester. For converting triglycerides of vegetable seed oil to the methyl ester, the base catalyst mixture was slowly added to the acid esterified vegetable seed oil within 15 minutes to 20 minutes to form a reaction mixture. The reaction mixture was kept under stirring for about 80 minutes to 90 minutes. The reaction mixture was transferred to the settler and allowed to settle for about 30 minutes to 45 minutes at ambient temperature to remove glycerin layer. During settling period phase separation occurs

and top layer of esterified vegetable seed oil and bottom layer of glycerin, methanol and potassium hydroxide mixture were formed.
Bottom layer of glycerin was removed and sent for further processing and recovery. The esterified vegetable seed oil layer was purified by filtration and dried to form vegetable seed oil methyl ester.
Example 5: Preparation of propyl esters of vegetable oil
Methyl ester of vegetable oil was converted to propyl ester by adding trimethylol propane and sodium methoxide under vacuum of 1 torr at a temperature of 130° C.
Example 6: Formulation of bio-based gear oil
The formulation of bio-based gear oil was prepared by blending about 65 gm to 70 gm propyl esters of vegetable oil with 6 gm to 8 gm of polyalfaolefms 100 and 0.1 gm to 0.3 gm of di-tert-butyl-p-cresol.
Advantages of the invention
1. The bio-based gear oil of the present invention have high lubricity, good shear strength, high flash point, low evaporation rate and is highly lubricant, biodegradable and non toxic.
2. The bio-based gear oil of the present invention reduces friction for smooth starting and efficient power transfer due to higher lubricity of the gear oil. The energy saving is in the range of about 20% as compared to the presently used mineral oil based or synthetic gear oils.

3. The bio-based gear oil of the present invention reduces temperature rise to almost
40% as a result of reduction in friction. Moreover, the noise and vibration levels are
also get reduced.
4. The temperature rise with the bio-based gear oil of the present invention is almost 40% less that helps in maintaining the high viscosity even at full load. Thus the 68 grade bio-based gear oil of the present invention replace mineral oil based or synthetic gear oils up to 360 grade and 90 grade bio-based gear oil 420 grade mineral based or synthetic based oil.
5. The bio-based gear oil of the present invention has low evaporation rate and high flash point. Hence frequent top-up or change of gear oil is not required.
6. The bio-based gear oil is biodegradable and non toxic. Hence it meets the mandatory requirements for food grade and pharma grade machines. Moreover, the disposal is simple by composting.
7. The gear oil of the present invention have high viscosity index of the oil and perform better than the recommended higher viscosity gear oils and avoid churning losses.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is

understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We Claim:
1. A bio-based gear oil formulation having superior lubricity and thin film
strength, the bio-based gear oil formulation comprising:
polyol ester of a vegetable seed oil in a range of 78% by weight to 90 % by weight;
polyalfaolefins in a range of 10 % by weight to 20 % by weight; and antioxidant in a range of 0.1 % by weight to 0.3 % by weight.
2. The bio-based gear oil formulation as claimed in claim 1, wherein the vegetable seed oil is selected from any one of Elaeis guineensis seed oil, Pongamia pinnata seed oil, mustard oil and combinations thereof.
3. The bio-based gear oil formulation as claimed in claim 1, wherein the antioxidant is di-tert-butyl-p-cresol.
4. The bio-based gear oil formulation as claimed in claim 1, wherein high viscosity index of the bio-based gear oil provides equivalent properties at lower viscosity, such as 68 grade (cSt) provides equivalent properties of mineral oil based or synthetic based gear oils having viscosity up to 320 grade (cSt) and viscosity at 90 grade (cSt) provides equivalent properties of mineral oil based or synthetic based gear oils having viscosity up to of 460 grade (cSt).
5. A process for preparation of a bio-based gear oil formulation, the process comprising the steps of:
preparing a methyl ester of vegetable seed oil;

adding trimethylol propane to the methyl ester in presence of an alkaline catalyst under a predefined vacuum and temperature thereby converting the methyl ester into polyol ester;
blending the polyol ester with polyalfaolefins-100 in a predefined proportion to form a mixture; and
adding an antioxidant to the mixture.
6. The process as claimed in claim 4, wherein the vegetable seed oil is selected from any one of Pongamia pinnata seed oil, Elaeis guineensis seed oil, mustard oil and combinations thereof.
7. The process as claimed in claim 4. wherein the conversion of methyl ester into propyl ester is adapted to be carried out under vacuum of 1 torr and at temperature of 130o C.
8. The process as claimed in claim 4, wherein the alkaline catalyst is sodium methoxide.
9. The process as claimed in claim 4. wherein the antioxidant is di-tert-butyl-p-cresol.