Title of Invention	A PROCESS FOR THE PREPARATION OF IMPREGNATED THIN FILM HYDROCARBON SENSOR MATERIALS USING SPRAY PYROLYSIS TECHNIQUE
Abstract	A new process for the preparation of metal impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique is demonstrated. The sensing material is specific to hydrocarbon gases and is negligibly affected by the presence of common automobile exhaust like NO2, CO and industrially used gases such as H2, NH3, H2S and fuel gases like petrol and diesel vapors. The process for the preparation of metal impregnated tin oxide thin film deposition on to substrates such as glass, alumina, silica and alike as described is easy with an added advantage of low cost manufacture for hydrocarbon gas sensing material. It is possible to tailor the sensitivity as well as the selectivity of the sensing material towards a particular hydrocarbon gas by selecting the appropriate metal and controlling their amount for impregnation in the film. Number of samples can be prepared in batches further reducing the cost of gas sensing material.

Title of Invention

A PROCESS FOR THE PREPARATION OF IMPREGNATED THIN FILM HYDROCARBON SENSOR MATERIALS USING SPRAY PYROLYSIS TECHNIQUE

Abstract

A new process for the preparation of metal impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique is demonstrated. The sensing material is specific to hydrocarbon gases and is negligibly affected by the presence of common automobile exhaust like NO2, CO and industrially used gases such as H2, NH3, H2S and fuel gases like petrol and diesel vapors. The process for the preparation of metal impregnated tin oxide thin film deposition on to substrates such as glass, alumina, silica and alike as described is easy with an added advantage of low cost manufacture for hydrocarbon gas sensing material. It is possible to tailor the sensitivity as well as the selectivity of the sensing material towards a particular hydrocarbon gas by selecting the appropriate metal and controlling their amount for impregnation in the film. Number of samples can be prepared in batches further reducing the cost of gas sensing material.

Full Text	The present invention relates to an improved process for the preparation of impregnated thin film hydrocarbon sensor materials using spray pyrolysis. More particularly, it relates to ruthenium impregnated tin oxide thin film that can be used to fabricate device capable of sensing leakage of liquefied petroleum gas (LPG) and other similar hydrocarbons. This thin film impregnated ceramic material can be used to make hydrocarbon sensors working on the principal of change in electrical properties as a result of the adsorption of hydrocarbons on the sensor element. The conventional materials available for sensing hydrocarbon gases are available in the form of bulk, thick film and thin film. Some of the methods used for the preparation of thin films arc Vacuum evaporation method; Dip coaling method; Sol-gel method; Spin-on coating method; Sputtering technique, Langmuir Blodgett method; Chemical vapour deposition method The above mentioned methods and their drawbacks are as below Vacuum evaporation method: The substance to be deposited is evaporated by means of method such as boiling, sublimation or by bombardment of electron beam and then deposited on the substance such as glass, alumina, quartz. Drawbacks: The requirement of very high vacuum and difficulty in getting the proper stoichiometry. The method is very expensive. Dip coating method: The soluble salts of metal oxides to be deposited have to be taken in appropriate ratios. The substrates on which deposition is to be made is dipped several times followed by heat treatment. Drawbacks: Poor adhesion and improper stoichiometry. Sol-gel method: Stable molecules in the suspended state are destabilized to very fine fine particles called gel which are deposited on the substrate during the process of formation of gel. The deposition is done by dipping the substrate in such solution. References may be made to US Patent 6,134,946 wherein the detection of CO employing nanocrystalline tin oxide film deposited by sol-gel method is discussed. The drawbacks are large cross-sensitivity, lack of specificity, which cannot be completely compensated by the use of dopants and additives, requirement of critical conditions for gel formation, non uniform film due to breaking of film during drying. Spin-on coating: Viscous solution is spread on the rotating substrate, followed by intermittent heating so as to get the required thickness of the film. Drawbacks: Mostly expensive organometalic compounds are required as precursors. Difficult to get the stoichiometry and required thickness. Reference may be made to antimony bearing tin oxide sensor (US Patent No. 5,4427,740) wherein the sensor shows a good sensitivity towards CO, CH4, and H20. References may also be made to US Patent No. 4,030,340 wherein the hydrogen gas is detected by a sensor made by depositing a palladium film on a stannic oxide film by sputtering. The prior art also has the drawbacks such as long-term drift, poisoning by humidity, temperature effects and lack of selectivity since they sense all oxidizable gases such as CO, hydrogen, alcohol, LPG etc. at comparable sensitivity values. Although the metal oxides are made from naturally available mineral resources and are more economical most of the noble metals used, as additives are not economically viable. References may also be made to U.S. Pat 6,103,080 wherein an electrochemical hydrocarbon sensor is discussed. A suitable proton conducting electrolyte and catalytic materials have been found for specific application in the detection and measurement of non-methane hydrocarbons. The sensor comprises a proton conducting electrolyte sandwiched between two electrodes. At least one of the electrodes is covered with a hydrocarbon decomposition catalyst. The drawbacks are sensor is very complicate, sensitivity is small. References may also be made to U.S. Pat 5,670,949 wherein a ceramic sensor comprising a thin film of Cu.sub.x Mn.sub.3-x O.sub.4 is provided that quantitatively measures the partial pressure of CO and hydrocarbon gases in a flowing system. The sensor is specific to both CO and hydrocarbon gases. The drawbacks are sensor is cross sensitive to CO and hydrocarbon gases. References may also be made to U.S. Pat 4,397,888wherein the thick film stannic oxide is disclosed whereby the sensitivity of the sensor to CO is enhanced by the addition of a rare earth oxide to the sensor composition and the catalytic reactivity of the sensor, when contacted by a gas containing a reducing constituent, i.e., H2 or CO and oxygen, is enhanced by employing RuCl3 or PtCl2 as a catalyst. The drawbacks are sensor is cross sensitive, process is very tedious. The main object of the present invention is to provide a process for the preparation of impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique, which obviates the drawbacks as detailed above. Another object o the present invention is to provide a process for the preparation of ruthenium impregnated thin film hydrocarbon sensor materials with better selectivity and high sensitivity for hydrocarbon gas. Still another object of the present invention is to prepare thin film of tin oxide impregnated with metals such as Pd, Ag, Pt, Au and combinations thereof Yet another object of the present invention is to prepare thin film of metal impregnated tin oxide at lower temperature on the substrates such as glass, alumina, and silica. Accordingly, the present invention provides a process for the preparation of impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique which comprises preparing a solution of tin compound selected from tin chloride or tin acetate and a metal halide separately in a solvent, mixing the above said solutions, obtaining the film of tin and metal composite on a substrate by a conventional methods at temperature in the range of 380-430°C, annealing the coated substrate for 3 to 12 hours at temperature in the range of 380-430°C to obtain the impregnated thin film. In an embodiment of the present - invention, the metal halide may be halide of ruthenium, platinum, palladium, silver, gold and combinations thereof In another embodiment the concentration of tin compound solution may be ranging 0.01 to 1.0 molar. In another embodiment the concentration of metal halide solution may be 0.01 molar. In another embodiment the solvent used for preparing the solution used for preparing the solution of tin chloride and metal halide may be isopropanol, alcohol, water and/or acetonitirle. In yet another embodiment the substrate may be soda glass, alumina, and silica. In a feature of the present invention, the film of tin and the metal is obtained on the substrate by using spray pyrolysis method carried out at a temperature ranging between 300° - 600°C. In another feature the process for the preparation of a thin film metal impregnated stannic oxide consists of two steps: Preparation of different millimolar stannic chloride solution from commercially available tin salts in solvents like ethanol , isopropanol, distilled water, and preparation of different millimolar solution of metal halides, MX3, where M represents Ruthenium, Palladium and Silver, X represents iodide, bromide, chloride and fluoride in solvents like ethanol, isopropanol, distilled water, and adding the smaller percentage of solution of MX3 in the solution of Stannic chloride and spraying the mixture together on commercially available substrates like soda glass, alumina. The process involves the preparation of metal impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique. The source of tin is tin chloride, tin acetate and solution of such metal halide (MX3) is impregnated with metals like ruthenium, platinum, and palladium, silver. In the present invention solvent used for preparing the solution of tin chloride and MX3 is selected from isopropanol, alcohol, water and / or acetonitrile. The substrate used is selected from soda glass, alumina, and silica. The solution with the appropriate ratio of tin to metal is spray pyrolysed onto substrates at the temperature ranging between 300°C and 600°C. These films are then subjected to post deposition heat treatment for 3 to 12 hours to get the final metal impregnated tin oxide films. The thin film sensor material prepared as per the process described in the present invention are especially suitable for sensing hydrocarbon gas even in the trace amounts and the main advantages of this invention include the use of noble metal compounds to enhance the sensitivity and selectivity. The thin film material requires very low amount of the precious metals such as rutheniun, palladium, silver, platinium as compared to their requirement for impregnation in the bulk type of similar sensing materials, the thin materials requires low power consumption during their use in the gas sensing device. For example the amount of Ruthenium for impregnation is in the range of 0.1 to 1.6 wt % in the tin oxide thin film matrix wherein the thickness is less than 1 micron. The present invention removes the drawbacks in the prior art materials as the modification of tin oxide thin films with metal creates surface states (donor-acceptor levels) in the band gap leading to improved selectivity and very high sensitivity towards hydrocarbon gases. The following examples are given by way of illustration and therefore should not be construed to limit the scope of the invention. EXAMPLE -1 0.1M solution of tin chloride was prepared in elhanol and 0.01 M solution of ruthenium chloride was prepared in isopropanol, followed by the addition of 0.35ml of RuCl3 to 0.63ml of 0.1M tin chloride so as to make the solution rich in 0.005M of ruthenium chloride. Both the solutions were mixed thougroully and were sprayed on the glass substrate at a temperature of 400°C. The films were then annealed for 6hrs at the same temperature in air. Energy Dispersive X-Ray Analysis (EDAX) using SEM have indicated 0.42% Ru on the surface of the film. EXAMPLE - 2 0.1M solution of tin chloride is prepared in ethanol and 0.01M solution of ruthenium chloride and palladium chloride was prepared in isopropanol. Then 0.35ml of RuCl3 and 0.35ml of PdCl2 were added to 0.63ml of 0.1M tin chloride so as to make the solution 4.76x10'3 M of ruthenium chloride and palladium chloride. Both the solutions were then mixed thougroully and were sprayed on the glass substrate at a temperature of 400°C. The films were then annealed for 6hrs at same temperature in air. Energy Dispersive X-Ray Analysis (ED AX) using SEM have indicated 0.42% Ru on the surface of the film. EXAMPLE - 3 0.1M solution of tin chloride was prepared in ethanol and 0.01M solution of ruthenium chloride, PdCU, AgN03 were prepared in isopropanol. Then 0.35ml of RuCl3 AgNO3, PdCl2 was added to 0.63ml of 0.1M tin chloride so as to make the solution ^*^-^>^ -,y 4.54X10'3 M of ruthenium chloride. All the solutions were then mixed r - and were sprayed on the glass substrate at a temperature of 400°C. The films were then annealed for 6hrs at same temperature in air. Energy Dispersive X-Ray Analysis (EDAX) using SEM have indicated 0.42% Ru on the surface of the film. The main advantages of the present invention arc: 1. An easy process for the preparation of metal impregnated thin film hydrocarbon sensor material using spray pyrolysis technique. 2. Sensor produced is with better selectivity and sensitivity for hydrocarbon gas. 3. Low power consumption for the preparation can deposit number of gas sensing thin film sensing material in a single batch. 4. Low cost of preparation as the process requires simple glass atomizer, heater temperature upto 600°C, commercially available glass, and alumina substrates. We Claim: 1. A process for the preparation of impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique which comprises preparing a solution of tin compound selected from tin chloride or tin acetate and a metal halide separately in solvent, mixing the above said solutions, obtaining the film of tin and metal composite on a substrate by a conventional methods at temperature in the range of 380-430°C, annealing the coated substrate for 3 to 12 hours at temperature in the range of 380-430°C to obtain the impregnated thin film. 2. A process as claimed in claim 1 wherein metal halide is halide of ruthenium, platinum, palladium, silver, gold and combinations thereof 3. A process as claimed in claims 1 and 2 wherein the concentration of tin compound solution used is 0.01 to 1.0 molar. 4. A process as claimed in claims 1 to 3 wherein the concentration of metal halide solution used is 0.01 to 1.0 molar. 5. A process as claimed in claims 1 to 4 wherein the solvent used for preparing the solution of tin chloride and metal halide is selected from isopropanol, alcohol, water and /or acetonitrile. 6. A process as claimed in claims 1 to 5 wherein the substrate used is soda glass, alumina, silica. 7. A process for the preparation of impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique substantially as herein described with reference to examples 1 to 3.

Full Text

The present invention relates to an improved process for the preparation of impregnated thin film hydrocarbon sensor materials using spray pyrolysis.
More particularly, it relates to ruthenium impregnated tin oxide thin film that can be used to fabricate device capable of sensing leakage of liquefied petroleum gas (LPG) and other similar hydrocarbons. This thin film impregnated ceramic material can be used to make hydrocarbon sensors working on the principal of change in electrical properties as a result of the adsorption of hydrocarbons on the sensor element. The conventional materials available for sensing hydrocarbon gases are available in the form of bulk, thick film and thin film. Some of the methods used for the preparation of thin films arc Vacuum evaporation method; Dip coaling method; Sol-gel method; Spin-on coating method; Sputtering technique, Langmuir Blodgett method; Chemical vapour deposition method
The above mentioned methods and their drawbacks are as below Vacuum evaporation method: The substance to be deposited is evaporated by means of method such as boiling, sublimation or by bombardment of electron beam and then deposited on the substance such as glass, alumina, quartz.
Drawbacks: The requirement of very high vacuum and difficulty in getting the proper stoichiometry. The method is very expensive.
Dip coating method: The soluble salts of metal oxides to be deposited have to be taken in appropriate ratios. The substrates on which deposition is to be made is dipped several times followed by heat treatment. Drawbacks: Poor adhesion and improper stoichiometry.

Sol-gel method: Stable molecules in the suspended state are destabilized to very fine fine particles called gel which are deposited on the substrate during the process of formation of gel. The deposition is done by dipping the substrate in such solution. References may be made to US Patent 6,134,946 wherein the detection of CO employing nanocrystalline tin oxide film deposited by sol-gel method is discussed. The drawbacks are large cross-sensitivity, lack of specificity, which cannot be completely compensated by the use of dopants and additives, requirement of critical conditions for gel formation, non uniform film due to breaking of film during drying. Spin-on coating: Viscous solution is spread on the rotating substrate, followed by intermittent heating so as to get the required thickness of the film. Drawbacks: Mostly expensive organometalic compounds are required as precursors. Difficult to get the stoichiometry and required thickness.
Reference may be made to antimony bearing tin oxide sensor (US Patent No. 5,4427,740) wherein the sensor shows a good sensitivity towards CO, CH4, and H20. References may also be made to US Patent No. 4,030,340 wherein the hydrogen gas is detected by a sensor made by depositing a palladium film on a stannic oxide film by sputtering. The prior art also has the drawbacks such as long-term drift, poisoning by humidity, temperature effects and lack of selectivity since they sense all oxidizable gases such as CO, hydrogen, alcohol, LPG etc. at comparable sensitivity values. Although the metal oxides are made from naturally available mineral resources and are more economical most of the noble metals used, as additives are not economically viable.

References may also be made to U.S. Pat 6,103,080 wherein an electrochemical hydrocarbon sensor is discussed. A suitable proton conducting electrolyte and catalytic materials have been found for specific application in the detection and measurement of non-methane hydrocarbons. The sensor comprises a proton conducting electrolyte sandwiched between two electrodes. At least one of the electrodes is covered with a hydrocarbon decomposition catalyst. The drawbacks are sensor is very complicate, sensitivity is small.
References may also be made to U.S. Pat 5,670,949 wherein a ceramic sensor comprising a thin film of Cu.sub.x Mn.sub.3-x O.sub.4 is provided that quantitatively measures the partial pressure of CO and hydrocarbon gases in a flowing system. The sensor is specific to both CO and hydrocarbon gases. The drawbacks are sensor is cross sensitive to CO and hydrocarbon gases.
References may also be made to U.S. Pat 4,397,888wherein the thick film stannic oxide is disclosed whereby the sensitivity of the sensor to CO is enhanced by the addition of a rare earth oxide to the sensor composition and the catalytic reactivity of the sensor, when contacted by a gas containing a reducing constituent, i.e., H2 or CO and oxygen, is enhanced by employing RuCl3 or PtCl2 as a catalyst. The drawbacks are sensor is cross sensitive, process is very tedious.
The main object of the present invention is to provide a process for the preparation of impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique, which obviates the drawbacks as detailed above.
Another object o the present invention is to provide a process for the preparation of ruthenium impregnated thin film hydrocarbon sensor materials with better selectivity and high sensitivity for hydrocarbon gas.
Still another object of the present invention is to prepare thin film of tin oxide impregnated with metals such as Pd, Ag, Pt, Au and combinations thereof
Yet another object of the present invention is to prepare thin film of metal impregnated tin oxide at lower temperature on the substrates such as glass, alumina, and silica.
Accordingly, the present invention provides a process for the preparation of
impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique
which comprises preparing a solution of tin compound selected from tin chloride or
tin acetate and a metal halide separately in a solvent, mixing the above said solutions,
obtaining the film of tin and metal composite on a substrate by a conventional
methods at temperature in the range of 380-430°C, annealing the coated substrate for
3 to 12 hours at temperature in the range of 380-430°C to obtain the impregnated thin
film.
In an embodiment of the present - invention, the metal halide may be halide of ruthenium,
platinum, palladium, silver, gold and combinations thereof
In another embodiment the concentration of tin compound solution may be ranging 0.01
to 1.0 molar.
In another embodiment the concentration of metal halide solution may be 0.01 molar.

In another embodiment the solvent used for preparing the solution used for preparing the solution of tin chloride and metal halide may be isopropanol, alcohol, water and/or acetonitirle.
In yet another embodiment the substrate may be soda glass, alumina, and silica.
In a feature of the present invention, the film of tin and the metal is obtained on the substrate by using spray pyrolysis method carried out at a temperature ranging between 300° - 600°C.
In another feature the process for the preparation of a thin film metal impregnated stannic oxide consists of two steps:
Preparation of different millimolar stannic chloride solution from commercially available tin salts in solvents like ethanol , isopropanol, distilled water, and preparation of different millimolar solution of metal halides, MX3, where M represents Ruthenium, Palladium and Silver, X represents iodide, bromide, chloride and fluoride in solvents like ethanol, isopropanol, distilled water, and adding the smaller percentage of solution of MX3 in the solution of Stannic chloride and spraying the mixture together on commercially available substrates like soda glass, alumina.
The process involves the preparation of metal impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique. The source of tin is tin chloride, tin acetate and solution of such metal halide (MX3) is impregnated with metals like ruthenium, platinum, and palladium, silver. In the present invention solvent used for preparing the solution of tin chloride and MX3 is selected from isopropanol, alcohol, water and / or acetonitrile. The substrate used is selected from soda glass, alumina, and silica. The solution with the appropriate ratio of tin to metal is spray pyrolysed onto substrates at the temperature ranging between 300°C and 600°C. These films are then subjected to post

deposition heat treatment for 3 to 12 hours to get the final metal impregnated tin oxide
films.
The thin film sensor material prepared as per the process described in the present
invention are especially suitable for sensing hydrocarbon gas even in the trace amounts
and the main advantages of this invention include the use of noble metal compounds to
enhance the sensitivity and selectivity. The thin film material requires very low amount
of the precious metals such as rutheniun, palladium, silver, platinium as compared to
their requirement for impregnation in the bulk type of similar sensing materials, the thin
materials requires low power consumption during their use in the gas sensing device.
For example the amount of Ruthenium for impregnation is in the range of 0.1 to 1.6 wt
% in the tin oxide thin film matrix wherein the thickness is less than 1 micron.
The present invention removes the drawbacks in the prior art materials as the
modification of tin oxide thin films with metal creates surface states (donor-acceptor
levels) in the band gap leading to improved selectivity and very high sensitivity towards
hydrocarbon gases.
The following examples are given by way of illustration and therefore should not be
construed to limit the scope of the invention.
EXAMPLE -1 0.1M solution of tin chloride was prepared in elhanol and 0.01 M solution of ruthenium chloride was prepared in isopropanol, followed by the addition of 0.35ml of RuCl3 to 0.63ml of 0.1M tin chloride so as to make the solution rich in 0.005M of ruthenium chloride. Both the solutions were mixed thougroully and were sprayed on the glass substrate at a temperature of 400°C. The films were then annealed for 6hrs at the same

temperature in air. Energy Dispersive X-Ray Analysis (EDAX) using SEM have indicated 0.42% Ru on the surface of the film.
EXAMPLE - 2 0.1M solution of tin chloride is prepared in ethanol and 0.01M solution of ruthenium chloride and palladium chloride was prepared in isopropanol. Then 0.35ml of RuCl3 and 0.35ml of PdCl2 were added to 0.63ml of 0.1M tin chloride so as to make the solution 4.76x10'3 M of ruthenium chloride and palladium chloride. Both the solutions were then mixed thougroully and were sprayed on the glass substrate at a temperature of 400°C. The films were then annealed for 6hrs at same temperature in air. Energy Dispersive X-Ray Analysis (ED AX) using SEM have indicated 0.42% Ru on the surface of the film.
EXAMPLE - 3 0.1M solution of tin chloride was prepared in ethanol and 0.01M solution of ruthenium chloride, PdCU, AgN03 were prepared in isopropanol. Then 0.35ml of RuCl3 AgNO3, PdCl2 was added to 0.63ml of 0.1M tin chloride so as to make the solution ^*^-^>^ -,y 4.54X10'3 M of ruthenium chloride. All the solutions were then mixed r - and were sprayed on the glass substrate at a temperature of 400°C. The films were then annealed for 6hrs at same temperature in air. Energy Dispersive X-Ray Analysis (EDAX) using SEM have indicated 0.42% Ru on the surface of the film. The main advantages of the present invention arc:
1. An easy process for the preparation of metal impregnated thin film hydrocarbon sensor material using spray pyrolysis technique.
2. Sensor produced is with better selectivity and sensitivity for hydrocarbon gas.

3. Low power consumption for the preparation can deposit number of gas sensing thin film sensing material in a single batch.
4. Low cost of preparation as the process requires simple glass atomizer, heater temperature upto 600°C, commercially available glass, and alumina substrates.

We Claim:
1. A process for the preparation of impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique which comprises preparing a solution of tin compound selected from tin chloride or tin acetate and a metal halide separately in solvent, mixing the above said solutions, obtaining the film of tin and metal composite on a substrate by a conventional methods at temperature in the range of 380-430°C, annealing the coated substrate for 3 to 12 hours at temperature in the range of 380-430°C to obtain the impregnated thin film.
2. A process as claimed in claim 1 wherein metal halide is halide of ruthenium, platinum, palladium, silver, gold and combinations thereof
3. A process as claimed in claims 1 and 2 wherein the concentration of tin compound solution used is 0.01 to 1.0 molar.
4. A process as claimed in claims 1 to 3 wherein the concentration of metal halide solution used is 0.01 to 1.0 molar.
5. A process as claimed in claims 1 to 4 wherein the solvent used for preparing the solution of tin chloride and metal halide is selected from isopropanol, alcohol, water and /or acetonitrile.
6. A process as claimed in claims 1 to 5 wherein the substrate used is soda glass, alumina, silica.
7. A process for the preparation of impregnated thin film hydrocarbon sensor materials using spray pyrolysis technique substantially as herein described with reference to examples 1 to 3.

Documents:

136-DEL-2002-Abstract-(31-1-2008).pdf

136-DEL-2002-Claims (23-06-2008).pdf

136-DEL-2002-Claims-(16-03-2009).pdf

136-DEL-2002-Claims-(27-02-2008).pdf

136-DEL-2002-Claims-(31-1-2008).pdf

136-DEL-2002-Claims-30-07-2008.pdf

136-del-2002-complete specification (granted).pdf

136-DEL-2002-Correspondence-Others(23-06-2008).pdf

136-DEL-2002-Correspondence-Others-(27-02-2008).pdf

136-DEL-2002-Correspondence-Others-(30-07-2008).pdf

136-DEL-2002-Correspondence-Others-(31-1-2008).pdf

136-DEL-2002-Description (Complete)-(27-02-2008).pdf

136-DEL-2002-Description (Complete)-(31-1-2008).pdf

136-del-2002-description (complete)-16-03-2009.pdf

136-del-2002-description (complete)-23-06-2008.pdf

136-del-2002-description (complete)-30-06-2008.pdf

136-DEL-2002-Form-1-(27-02-2008).pdf

136-DEL-2002-Form-3-(27-02-2008).pdf

136-DEL-2002-Form-3-(31-1-2008).pdf

abstract.pdf

claims.pdf

correspondence-others.pdf

correspondence-po.pdf

description complete.pdf

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Patent Number

233595

Indian Patent Application Number

136/DEL/2002

PG Journal Number

14/2009

Publication Date

27-Mar-2009

Grant Date

31-Mar-2009

Date of Filing

22-Feb-2002

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	NIRANJAN SURYAKANT RAMGIR	CHEMICAL LABORATORY, PUNE-411008, MAHARASHTRA, INDIA
2	VARSHA ASHISH CHAUDHARY	CHEMICAL LABORATORY, PUNE-411008, MAHARASHTRA, INDIA
3	VIJAYMOHANAN KUNJUKRISHNAPILLAI	CHEMICAL LABORATORY, PUNE-411008, MAHARASHTRA, INDIA
4	IMITIAZ SIRAJUDDIN MULLA	CHEMICAL LABORATORY, PUNE-411008, MAHARASHTRA, INDIA

PCT International Classification Number

B05D 1/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA