FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A low oleic acid rapeseed oil based transformer fluid
APPLICANTS
EMCO Limited, Plot No F-5, Road No 28, Wagle Industrial Estate, Thane - 400 604, Maharashtra, India, an Indian company
INVENTORS
Patel Mahendra Jethabhai, Varughese John, Krishnamoorthy Perody Ananthakrishna and Vagish Shrinet, all of Electrical Research and Development Association (ERDA), ERDA Road, Makarpura Industrial Estate, VADODARA - 390 010, Gujarat State India, and Jain Mohan Lai of EMCO Limited, Plot No F-5, Road No 28, Wagle Industrial Estate, Thane - 400 604, Maharashtra, India, all Indian nationals
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
This invention relates to a low oleic acid rapeseed oil based transformer fluid
This invention also relates to a method of improving electrical properties of low oleic acid rapeseed oil and low oleic acid rapeseed oil having improved electrical properties obtained by the method.
BACKGROUND OF THE INVENTION
Transformer fluids are generally petroleum based fluids which are non-bio-degradable, nonrenewable and non-environmental friendly, scarce and expensive. Spillage of petroleum based transformer fluids not only pollutes the environment but also causes great economic losses. There is, therefore, a great need for alternative transformer fluids without the above disadvantages and there has been constant search for the same. Canola oil is reported to be used as transformer oil. Canola oil comprises oil extracted from genetically modified rapeseeds from rape plants grown in Canada and chemically modified for use as transformer oil. Rapeseed oil extracted from genetically modified rapeseed comprises high oleic acid > 35%. The exact nature of the chemical treatment imparted to the rapeseed oil extracted from genetically modified rapeseed is proprietary in nature and is not reported. However, rapeseed oil extracted from rapeseed plants grown locally, indigenously has low oleic acid upto 15 to 20% and is not as such suitable for dielectric applications including use as transformer oil. There is, thus, need for rendering low oleic acid rapeseed oil suitable for dielectric applications, especially for use as transformer oil, as the low oleic acid rapeseed oil is biodegradable, renewable and environmental friendly and is naturally available at very low cost and does not cause any shortage of edible oil.

OBJECTS OF THE INVENTION
An object of the invention is to provide a low oleic acid rapeseed oil based transformer fluid
which is non-edible biodegradable, renewable and environmental friendly.
Another object of the invention is to provide a low oleic acid rapeseed oil based transformer fluid which is naturally available in plenty at very low cost and which does not cause any shortage of edible oil.
Another object of the invention is to provide a method of improving electrical properties of low oleic acid rapeseed oil, which is non-edible, biodegradable, renewable and environmental friendly.
Another object of the invention is to provide a method of improving electrical properties of low oleic acid rapeseed oil, which is naturally available in plenty at very low cost and which does not cause any shortage of edible oil.
Another object of the invention is to provide a method of improving electrical properties of low oleic acid rapeseed oil, which method is simple and easy to carry out.

Another object of the invention is to provide a low oleic acid rapeseed oil having improved electrical properties obtained by the above method.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a low oleic acid rapeseed oil based transformer fluid, wherein the low oleic acid rapeseed oil is chemically modified to have improved electrical properties.
According to the invention there is also provided a low oleic acid rapeseed oil based transformer
fluid, wherein the low oleic acid rapeseed oil is chemically modified to have improved electrical
properties by the method comprising:
i) deacidifying the rapeseed oil with an alcoholic alkali;
ii) removing soap and residual alkali in the deacidified oil by washing the oil with hot water
at 80 to 100°C;
iii) removing residual soap in the deacidified oil under vacuum;
iv) removing polar compounds in the deacidified oil by treating the oil with China clay
comprising high magnesium oxide content;
v) heating the oil to 80 to 105 °C and subjecting the oil to filtration at 80 to 105 °C;
vi) modifying the viscosity of the oil by treating the oil with a viscosity modifier;
vii) deacidifying the oil by treating the oil with a deacidifying agent;
viii) heating the oil to 80 to 105 °C and subjecting the oil to filtration at 80 to 105 °C;
ix) removing residual polar compounds in the deacidified oil by further treating the oil with
China clay comprising high magnesium oxide content; and

x) stabilising the oil by treating the oil with an antioxidant
According to the invention there is also provided a method of improving electrical properties of
low oleic acid rapeseed oil, the method comprising:
i) deacidifying the rapeseed oil with an alcoholic alkali;
ii) removing soap and residual alkali in the deacidifled oil by washing the oil with hot water
at 80 to 100°C;
iii) removing residual soap in the deacidified oil under vacuum;
iv) removing polar compounds in the deacidified oil by treating the oil with China clay
comprising high magnesium oxide content;
v) heating the oil to 80 to 105 °C and subjecting the oil to filtration at 80 to 105 °C;
vi) modifying the viscosity of the oil by treating the oil with a viscosity modifier;
vii) deacidifying the oil by treating the oil with a deacidifying agent;
viii) heating the oil to 80 to 105 °C and subjecting the oil to filtration at 80 to 105 °C;
ix) removing residual polar compounds in the deacidified oil by further treating the oil with
China clay comprising high magnesium oxide content; and
x) stabilising the oil by treating the oil with an antioxidant-
The low oleic acid rapeseed oil generally comprises upto 15 - 20°/o of oleic acid. The alcoholic alkali is preferably methanol and potassium hydroxide. The methanol content is preferably 2 to 4% and still preferably 2.24% by volume of the oil and potassium hydroxide content is preferably 0.5 to 1.5 gm and still preferably 0.96 gm per litre of the oil. The China clay with high magnesium oxide content is, preferably Fuller's earth. Preferably, the Fuller's earth comprises 50

gms per litre of the oil. The viscosity modifier is preferably methyl ester. Preferably the methyl ester comprises 5% by volume of the oil and is obtained by transesterification of rapeseed oil. Preferably the deacidifying agent is QnF (an alkaline compound under the trade mark QnF of Coorga Renewables) and the QnF comprises preferably 0.1 to 0.2% and still preferably 0.2% of the oil. QnF is known to be used in the process for preparation of biodiesel. Preferably the antioxidant is ten - butyl - hydroquinone (TBHQ) and the tert - butyl - hydroquinone is 3 gm per litre of the oil. The Fuller's earth as used in the process of the invention is marketed by E-Merck. Heating of the oil helps to remove moisture from the oil. Filtration of the oil in the hot condition thereof prevents absorption of moisture by the oil from the atmosphere. Filtration of the oil in the hot condition also improves the rate of filtaration, The polar compounds that are removed from the oil include metallic soaps or chlorophyll pigments.
The following experimental example is illustrative of the invention but not limitative of the scope thereof:
Example 1
Indigenously obtained rapeseed oil having 15% oleic acid and properties as stated in the following Table 1 was used according to the invention:

Table 1
Sr.
No. Properties
\ Appearance Clear, YeUow
2 Colour 1.0
3 Relative Density, 0.91
4 pour Point, °C -12
5 Acid Number, mg of KOH/g 0.58
6 Kinematic Viscosity, cSt, at 40°C at 100°C 49 10
7 Dielectric strength, kV/2.0 mm gap at
25°C 17
8 Dielectric Constant, at 25°C 3.1
9 Dielectric dissipation Factor at 25°C at 100°C 0.0215 0.318
10 Water Content, mg/Kg 608
11 Flash Point, Open, °C 314
12 Fire Point, Open, °C 334

The rapeseed oil was deacidifled by treatment with an alcoholic alkali mixture of methanol 2.24 % by volume of the oil and potassium hydroxide 0.96 gms per liter of the oil. Soap as well as residual alkali in the oil was removed by washing the oil with hot water at 90 °C. Residual soap

in the deacidified oil was removed under vacuum. The oil was then treated with Fuller's earth (50 gms per liter of the oil) to remove polar compounds and heated to 90°C and filtered at 90 °C. Methyl ester (5% by volume of the oil) was added to the oil to adjust the viscosity and the oil was treated with QnF™ (1.3 gm per liter of the oil) for further deacidification. The oil was heated to 90 °C and filtered at 90 °C and further treated with Fuller's earth (50 gms per litre of the oil). The oil was stabilised by treatment with tert - butyl - hydroquinone (3 gm per litre of the oil).
The properties of the treated oil were as shown in the following Table 2:

Table 2
Sr. Properties Modified rapeseed oil ASTMD 6871-03
No. standard
1 Appearance Clear and light yellow Bright and clear
2 Color 1.0 Max: 1.0
3 Relative Density 0.90 Max:0.96
4 Pour Point, °C -11 Max: -10
5 Acid Number, mg of KOH/gm 0.04 Max: 0.06
6 Kinematic Viscosity, cSt,
at 40°C 43 Max: 50
at 100°C 11 Max: 15
7 Dielectric strength, kV/2.0mm gapat25°C 69 Min:30
8 Dielectric Constant, at
25°C 3.1 Max 3.3
9 Dielectric Dissipation Factor
at 25 °C 0.0018 Max 0.002
at 100°C 0.026 Max 0.04
10 Water Content, mg/kg 85 Max 200
11 FlashPoint, Open, °C 280 Min:275
When compared with the values in Table 1, it is seen in Table 2 that the acid number of the treated oil is substantially improved. The dielectric strength and dielectric dissipation factor and heat transfer capability of the treated oil are improved (as is evident from the increased dielectric

strength and reduced dielectric dissipation factor and reduced viscosity). The treated oil is thus ideal for use in electrical applications, especially as transformer oil. However, the treated oi! also can be used for any other dielectric applications. According to the invention, low oleic acid rapeseed oil is chemically modified to render it suitable for use as transformer oil and for other electric applications. Rapeseed oil is naturally available in plenty at very low cost. It is biodegradable, renewable and environmental friendly. Being mostly non-edible in nature, its use as transformer oil or in other dielectric applications does not cause any problem or shortage of oil for human consumption.

We claim
1) A low oleic acid rapeseed oil based transformer fluid, wherein the low oleic acid rapeseed oil is chemically modified to have improved electrical properties.
2) The transformer fluid as claimed in claim 1, wherein the rapeseed oil comprises upto 15 - 20% oleic acid.
3) A low oleic acid rapeseed oil based transformer fluid, wherein the low oleic acid rapeseed oil is chemically modified to have improved electrical properties by the method comprising:
i) deacidifying the rapeseed oil with an alcoholic alkali;
ii) removing soap and residual alkali in the deacidified oil by washing the oil with hot water
at 80 to 100°C;
iii) removing residual soap in the deacidified oil under vacuum;
iv) removing polar compounds in the deacidified oil by treating the oil with China clay
comprising high magnesium oxide content;
v) heating the oil to 80 to 105 °C and subjecting the oil to filtration at 80 to 105 °C;
vi) modifying the viscosity of the oil by treating the oil with a viscosity modifier;
vii) deacidifying the oil by treating the oil with a deacidifying agent;
viii) heating the oil to 80 to 105 °C and subjecting the oil to filtration at 80 to 105 °C;
ix) removing residual polar compounds in the deacidified oil by further treating the oil with
China clay comprising high magnesium oxide content; and
x) stabilising the oil by treating the oil with an antioxidant.

4) The method as claimed in claim 3, wherein the rapeseed oil comprises upto 15 - 20% of oleic acid.
5) The method as claimed in claim 3 or 4, wherein the alcoholic alkali comprises methanol and potassium hydroxide.
6) The method as claimed in claim 5, wherein the methanol content is preferably 2 to 4% and still preferably 2.24% by volume of the oil and the potassium hydroxide content is preferably 0.5 to 1.5 gm and still preferably 0.96 gm per litre of the oil.
7) The method as claimed in any one of claims 3 to 6, wherein the China clay with high magnesium oxide content is Fuller's earth.
8) The method as claimed in claim 7, wherein the Fuller's earth comprises 50 gms per litre of the oil
9) The method as claimed in any one of claims- 3 to 8, wherein the viscosity modifier is methyl ester.
10) The method as claimed in claim 9, wherein the methyl ester comprises 5% by volume of the oil.

11) The method as claimed in claim 9 or 10, wherein the methyl ester is obtained by transesterification of rapeseed oil.
12) The method as claimed in any one of claims 3 to 11, wherein the deacidifying agent is QnF.
13) The method as claimed in claim 12, wherein the QnF comprises preferably 0.1 to 0.2% and still preferably 0.2% of the oil.
14) The method as claimed in any one of claims 3 to 13, wherein the antioxidant is tert -butyl - hydroquinone.
15) The method as claimed in claim 14, wherein the tert - butyl - hydroquinone is 3 gm per litre of the oil.
16) A method of improving electrical properties of low oleic acid rapeseed oil, the method comprising:
i) deacidifying the rapeseed oil with an alcoholic alkali;
ii) removing soap and residual alkali in the deacidified oil by washing the oil with hot water
at 80 to 100°C;
iii) removing residual soap in the deacidified oil under vacuum;
iv) removing polar compounds in the deacidified oil by treating the oil with China clay
comprising high magnesium oxide content;

v) heating the oil to 80 to 105 °C and subjecting the oil to filtration at 80 to 105 °C;
vi) modifying the viscosity of the oil by treating the oil with a viscosity modifier;
vii) deacidifying the oil by treating the oil with a deacidifying agent;
viii) heating the oil to 80 to 105 °C and subjecting the oil to filtration at 80 to 105 °C;
ix) removing residual polar compounds in the deacidified oil by further treating the oil with
China clay comprising high magnesium oxide content; and
x) stabilising the oil by treating the oil with an antioxidant.
17) The method as claimed in claim 16, wherein the rapeseed oil comprises upto 15 - 20% of . oleic acid.
18) The method as claimed in claim 16 or 17, wherein the alcoholic alkali comprises methanol and potassium hydroxide.
19) The method as claimed in claim 18, wherein the methanol content is preferably 2 to 4% and still preferably 2.24% by volume of the oil and the potassium hydroxide content is preferably 0.5 to 1.5 gm and still preferably 0.96 gm per litre of the oil.
20) The method as claimed in any one of claims 16 to 19, wherein the China clay with high magnesium oxide content is Fuller's earth.
21) The method as claimed in claim 20, wherein the Fuller's earth comprises 50 gms per litre of the oil

22) The method as claimed in any one of claims 16 to 21, wherein the viscosity modifier is methyl ester.
23) The method as claimed in claim 22, wherein the methyl ester comprises 5% by volume of the oil.
24) The process as claimed in claim 22 or 23, wherein the methyl ester is obtained by transesterification of rapeseed oil.
25) The method as claimed in any one of claims 16 to 24, wherein the deacidifying agent is QnF.
26) The method as claimed in claim 25, wherein the QnF comprises preferably 0.1 to 0.2% and still preferably 0.2% of the oil.
27) The method as claimed in any one of claims 16 to 26, wherein the anti-oxidant is tert
- butyl - hydroquinone.
28) The method as claimed in claim 27, wherein the tert - butyl - hydroquinone is 3 gm per
litre of the oil.

29) Low oleic acid rapeseed oil having improved electrical properties obtained by the method as claimed in anyone of claims 16 to 28.