Title of Invention	A METHOD OF MANUFACTURING PLASTIC FILM CAPACITORS WITH AMINE BASED EPOXY IMPREGNATION AND PLASTIC FILM CAPACITORS MANUFACTURED THEREOF
Abstract	A present invention relates to an impregnation process of plastic film capacitors by an amine based epoxy as an impregnant, which during impregnation is in liquid state and after impregnation converts to solid state for improving the capacitor breakdown voltage and insulation resistance, thereby increasing the life expectancy on account of its ability to absorb high voltage surges when the capacitor is used for the intended purpose.

Title of Invention

A METHOD OF MANUFACTURING PLASTIC FILM CAPACITORS WITH AMINE BASED EPOXY IMPREGNATION AND PLASTIC FILM CAPACITORS MANUFACTURED THEREOF

Abstract

A present invention relates to an impregnation process of plastic film capacitors by an amine based epoxy as an impregnant, which during impregnation is in liquid state and after impregnation converts to solid state for improving the capacitor breakdown voltage and insulation resistance, thereby increasing the life expectancy on account of its ability to absorb high voltage surges when the capacitor is used for the intended purpose.

Full Text	FORM 2 THE PATENTS ACT, 1970 (39 FO 1970) & PATENT RULES, 2003 COMPLETE SPECIFICATION (See section 10 and rule 13) l.TTTLE OF THE INVENTION: A method of manufacturing plastic film capacitors with amine based epoxy impregnation and plastic film capacitors manufactured thereof 2. APPLICANT(S) (a) Name : CTR Manufacturing Industries ltd. (b) Nationality : Indian Company (c) Address : E 1, Chikalthana, AURANGABAD-431210, MAHARASHTRA, INDIA 3. PREAMBLE TO THE DESCRIPTION : The following opacification particularly dasoribas the invention and tha manner in which it is to ba parformad. A method of manufacturing plastic film capacitors with amine based epoxy impregnation and plastic film capacitors manufactured thereof. Field of invention: The present invention relates to a method of manufacturing plastic film capacitors. More particularly it relates to a method of manufacturing plastic film capacitors by impregnation of the plastic film using an amine based epoxy as an impregnant which during impregnation is in liquid state and which after impregnation converts to solid state mere by improving the breakdown voltage and insulation resistance consequently increasing life expectancy on account of ability to handle high voltage surges when capacitors are used for the intended purpose. Prior art: Wherever improvement in voltage withstand capacity is required in capacitors, impregnation process by oil, gas, amide base aromatic liquids, aromatic hydrocarbon liquid or amide base epoxide with or without vacuum, is used, often leading to: 1. Gas leakage 2. Oil oozing out 3. Degradation of voltage, after use 4. Degradation of insulation resistance, after use Japanese patent JP9213564 relates to a capacitor which is impregnated with electric insulating oil composed of olefin Oligomor, an aromatic group hydrocarbon having at least three benzene rings. As to olefin Oligomor content of fraction whose molecular weight is almost 500 is less man or equal to 7wt %,(to olefin Oligomor of lOOwt %), and content of fraction whose molecular weight is at most 400 is less man or equal to 7wt%, The above olefin Oligomer of 5-95wt%, is mixed with electrically t insulating oil of 100wt% for impregnation. The aromatic group hydrocarbon to be mixed with olefin Otigomor has at least three benzene rings. The above aromatic group hydrocarbon of 95-10wt % is mixed based on 100 % of the electrically insulating oil for insulation. US patent 5384684 relates to Metallised plastic film capacitor. It teaches about capacitor comprising a metallised plastic film impregnated with an electrically insulating oil composition, said composition comprising 5% to 10 % by weight ,bascd on the total weight of the composition, of a natural fatty acid triglyceride containing less than 10 % by weight of a fatty acid ester having three hydroxyl radicals and the remainder of the composition being an aromatic hydrocarbon .liquid at -30 °C, Canadian patent CA2467290 relates to an invention which provides an all-film oil- impregnated capacitor in which the dielectric layers consists only of a plastic resin film such as a biaxially oriented poly propylene resin film (OPP) suitable for use in microwave ovens. The all film capacitor of the invention can be obtained and has satisfactory propeities only when prepared by using specified materials including the OPP film, aluminum foil and capacitor oil and under specified conditions relative to me dielectric tangent values and dielectric capacity values before and after impregnation with a capacitor oil as well as the conditions in the steps of oil impregnation. US patent 4117579 relates to metallised plastic film capacitor. It briefly explains about impregnation of capacitor by using epoxide. According to this US patent between about 0.01 and 10.0% by weight of an antioxidant, and between about 0.1 and 10% by weight of an epoxide are added to a liquid aromatic ester prior to refining or purification of me ester and prior to use of me ester US" patent 5719742 discloses a metallised plastic film capacitor which is impregnated with an electrically insulating oil composition comprising 10 to 95 % by weight of an aromatic hydrocarbon having at least 3 benzene rings and 90 to 5 %by weight of an olefin oligomer containing 7 % by weight or less of a fraction having molecular weight of 500 or less and 2 % by weight or less of a fraction having a molecular weight of 400 or less, US patent 4598335 discloses impregnated wound capacitor comprises dielectric strips which consists at least partially of plastic foils swelled by the impregnant The electrodes of regenerabty thin metal layers are connected at the end faces of the capacitor coil with end contact layers. Impregnation holes are arranged in the dielectrically active part of the coil such mat me maximum spacing between successive holes on the capacitor surface is equal to R=r.sqroot3, where r is the impregnation reach. All the above prior art systems discuss regarding impregnation of a capacitor and do not disclose disadvantages such as swelling and aggravation of plastic films due to amide based epoxide and aromatic hydrocarbon compound, which affect and weaken the dielectric strength leading to deterioration of capacitance value, and/or insulation resistance. A plastic film capacitor completely fails or its capacitance value defoliates due to surges encountered during its usage because of the design, and / or process and / or impregnant used. Because of non impregnation and/ or impregnation with any impregnant disclosed in the prior art, it is observed that the failure of the plastic film capacitor occurs. Hence it is necessary to overcome the above drawbacks of the prior art and to provide plastic film capacitors that overcome all the above mentioned drawbacks of the prior art systems. Objective of the invention: The objective of the present invention is to provide improved plastic film capacitors, which eliminate the above said drawbacks associated with the prior art system. Anolher objective of the present invention is to impregnate a plastic film capacitor with an amine based epoxy as an impregnant that during impregnation is in liquid state and after impregnation converts to solid state. Anolher objective of the present invention is to improve the breakdown voltage and insulation resistance of plastic film capacitors to increase the life expectancy despite absorbing high voltage surges when capacitors are used for the intended purpose. Yet another objective of the present invention is to avoid swelling and aggravation of the plastic film due to amide based epoxide and aromatic hydrocarbon compound, which will affect the dielectric strength and weaken the dielectric constant leading to deterioration of capacitance value, and / or insulation resistance. Yet another objective of the present invention is to enhance the life of the plastic film capacitors, improving their reliability by providing better high voltage withstanding capacity of capacitors. Yet another objective of the present invention is to eliminate humming noise observed during intended use of plastic film capacitors at alternating frequency. Yet another objective of the present invention is to provide a method of impregnating plastic film capacitors, for the intended use, having minimal intricacies during processing. Accordingly the invented method of manufacturing plastic film capacitors comprising: a. placing under a vacuum a plastic dielectric film and depositing a thin layer of metal alloy as an electrodes on it; b. winding a metallised film into a cylinder so that a metallised edge extends on each end of the wound capacitor section; c. Heating a wound capacitor in air ventilated oven at a temperature of 110^ for me time period of 5 hours; d. spraying both ends with small droplets of molten metal that adhere alone & make contact with the metallisation on the film; e. soldering /welding the wire lead to this end sprayed metallised portion for making termination contact; f. preheating the capacitor coil obtained in step ( e ) by keeping in the air ventilated oven at the temperature between 85 to 107 oC for time period of 1 to 2 hours; g. Impregnating said preheated capacitor coils with amine based epoxy under vacuum for the period of 10-15 minutes ; wherein said amine base epoxy contains amine base resin and hardener in the ratio of 100:72.5 and having property of solidifying at temperature of 100 C and said epoxy is kept under vacuum before impregnation to remove excess air inside the said epoxy; h. drying the said impregnated capacitor coil by keeping it in air ventilated oven at a temperature of 107°C and i. Encapsulating and sealing dried impregnated capacitor coil Mostly capacitor coil is preheated at a temperature of 85 C .In this method during impregnation process amine based epoxy penetrates inside the capacitor coil and fills up the air pockets thereby sealing the capacitor coil Also there is provided a plastic film capacitor manufactured by the above mentioned method of the present invention. Brief description of the drawings : • Figure 1: showing wound capacitor coil. Figure 2: showing cross sectional area of wound capacitor coil. Figure 3: showing wound capacitor coil with end spray metallisation. Figure 4: showing wound capacitor coil with end spray metallisation and termination soldered. Figure 5: shows amine based epoxy impregnated capacitor coil according to the present invention. Figure 6: shows cross sectional area of amine base epoxy impregnated capacitor coil according to the present invention. Figure 7: shows process flow chart of the said invented process of epoxy impregnation. Detailed description of the invention The above, and other objects, features and advantages of the invention will become apparent from the following description read in conjunction with the accompanying drawings. Meaning of the reference numerals used in the drawings are as follows: 1.-Wound capacitor coil 2.- Electrodes 3.- Dielectric film 4.- End spray metallisation 5.- Lead wires 6.- Wekung/soldering contact 7.-Amine based epoxy According to present invention, plastic film capacitors are manufactured by winding into a cylinder any dielectric plastic film and any electrode. Fig 1 shows a wounded capacitor coil(l). Fig 2 shows the cross sectional area of a wound capacitor coil(l). As shown in figure2 eletrodes( 2 ) are placed between dielectric films (3 ). After winding, capacitor coils(l) are kept in air ventilated oven for heat treatment for 5 hrs. at a temperature 110°C and then end spray metallisation( 4 ) is done for tennination contact Fig 3 shows a capacitor coil with end spray metallisation. Then the lead wires (5) are soldered / welded to the ends of the sprayed coil for inaking termination contact Figure 4 shows the wound capacitor coil with end spray metallisation and termination soldered. Tennination/ lead wires ( 5 ) and welding/soldering contacts (6) are shown in figure 4. After this these capacitor coils (1) are kept in air-ventilated oven at a temperature between 85 to 107°C for a time period 1 to 2 hours for preheating. Then the amine based epoxy ( 7) containing amine based resin and hardener in the ratio of 100:72.5 and having the property of becoming solid at temperature of 100°C is taken and said epoxy is kept under vacuum to remove air in the epoxy. The resin used in the present invention is ETH-30 and hardener used is ETRF-30. Preheated capacitor coils are men immersed in said epoxy for impregnation under vacuum for a period of 10 to 15 minutes. During the epoxy impregnation processes under vacuum, epoxy penetrates into the capacitor coil and fills up the air voids / pockets and seals the capacitor coil for protection from atmosphere and improves the breakdown voltage since air pockets odierwise damage the plastic film during its usage in field conditions. Figure 5 shows the said epoxy impregnated capacitor coil Figure 6 shows the cross sectional area of the epoxy impregnated capacitor coil After impregnation these coils are kept in an air ventilated oven at a temperature of 107 °C for drying of the said epoxy. After drying, the impregnated coils are encapsulated. Figure 7 shows me flow chart of the process of present invention as discussed in the above description of the invention. Best mode of carrying out invention: First a plastic dielectric film is placed in vacuum and a thin layers of metal alloy as an electrode is deposited on it Then a metallised film is wound into a cylinder so mat a metallised edge extends on each end of the wound capacitor section. Then these capacitor coils are kept in air ventilated oven for 5 hrs. for heat treatment Then both ends are sprayed with small droplets of molten metal that adhere along & make contact with the metallisation on the film. Then the wire lead is soldered/welded to this end sprayed metallised portion for making termination contact There after the capacitor coil is preheated by keeping it in air ventilated oven at the temperature of 85° C for time period of 2 Hours. Then the amine based epoxy containing amine base resin and hardener in the ratio of 100:72.5 and which having property of getting solid at temperature of 100 °C is taken and said epoxy is kept under vacuum to remove the excess air inside the epoxy. The hardener used in the present invention is ETH-30 and resin used is ETRF-30. The preheated capacitor coils are then immersed in said epoxy for impregnation under vacuum for a period of 15 minutes. During the epoxy impregnation process under vacuum epoxy will penetrate inside me capacitor coil and fillup the air pockets and seal the capacitor coil to protect from atmosphere and improves breakdown voltage since air pockets otherwise damage the plastic film during its usage in field condition. After impregnation these coils are kept in the air ventilated oven at a temperature of 107 °C for drying of said epoxy. After drying, the impregnated coils are encapsulated and sealed. Advantages of the invention: 1. The present invention improves breakdown voltage and insulation resistance of plastic film capacitors to increase the lift expectancy on account of ability to absorb high voltage surges when capacitors are used for the intended purpose. 2. Another advantage of the present invention is to avoid swelling and aggravation of plastic due to amide based epoxide and aromatic hydrocarbon compound, which affects the dielectric strength and weakens the dielectric constant and also leading to deterioration of capacitance value. 3. Yet another advantage of the present invention is impregnation of plastic film capacitors with an amine based epoxy as an impregnant mat during impregnation is in liquid state and after impregnation converts to solid state avoiding oozing and / or leakage of the impregnant Industrial Application: Plastic film capacitors of the present invention are used in the electronics industry. The present invention is useful in various electronic circuits where high voltage withstanding capacity of the plastic film capacitor is required. The present invention is not limited to the above described embodiments , and various changes may be made, if desired, widiout departing from the essence or spirit of the invention which can be read from the claims and the entire specification. All these changes are also intended to be wthin technical scope of the present invention. claim: . A method of manufacturing a plastic film capacitor comprising: a. placing in vacuum a plastic dielectric film and depositing a thin layer of metal alloy as an electrodes on it; b. winding a metallised film into a cylinder so mat metallised edge extends on each end of the wound capacitor section; c. heating a wound capacitor in air ventilated oven at a temperature of 110°C for the time period of 5 hours; d. spraying both ends with small droplets of molten metal mat adhere along & make contact with the metallisation on the film; e. soldering / welding the wire lead to this end sprayed metallised portion for making termination contact; f. preheating the capacitor coil obtained in step (e ) by keeping it in air ventilated oven at temperature between 85 to 107oC for the period of 1 to 2 hours; g. impregnating said preheated capacitor coils with amine base cpoxy under vacuum for a period of 10 to IS minutes; wherein said amine base cpoxy contains amine base resin and hardener in the ratio of 100:72.5 and having property of getting solid at temperature of 100 *C and epoxy is kept under vacuum before impregnation to remove excess air inside saidepoxy; h. drying said impregnated capacitor coil by keeping it in air ventilated oven at a temperature of 107oC; i. encapsulating and sealing dried impregnated capacitor coil 2. A method of manufacturing plastic film capacitor as claimed in claim 1 wherein capacitor coil is preheated at temperature of 85 oC. 3. A method of manufacturing plastic film capacitor as claimed in claim 1 wherein preheating of capacitor coil is done for period of 1 hour. 4. A method of manufacturing plastic film capacitor as claimed in claim 1 wherein impregnation is carried out for a period of 10 minutes. 5. A method of manufacturing plastic film capacitor as claimed in claim 1 wherein during impregnation process amine base epoxy penetrates inside the capacitor coil and fills up the air pockets and seal the capacitor coil 6. Plastic film capacitor manufactured by the method as claims in 7. A method of manufacturing plastic film capacitor as herein described with reference to accompanying drawings. 8. Plastic film capacitor as herein described with reference to accompanying drawings. Dated this on 11th day of August 2006. For CTR Manufacturing Industries Ltd., Mr.A.R Kumar Managing Director

Full Text

FORM 2
THE PATENTS ACT, 1970
(39 FO 1970)
&
PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
l.TTTLE OF THE INVENTION: A method of manufacturing plastic film capacitors with amine based
epoxy impregnation and plastic film capacitors manufactured thereof
2. APPLICANT(S)
(a) Name : CTR Manufacturing Industries ltd.
(b) Nationality : Indian Company
(c) Address : E 1, Chikalthana,
AURANGABAD-431210, MAHARASHTRA, INDIA
3. PREAMBLE TO THE DESCRIPTION :
The following opacification particularly dasoribas the invention and tha manner in which it is to ba parformad.

A method of manufacturing plastic film capacitors with amine based epoxy impregnation and
plastic film capacitors manufactured thereof.
Field of invention:
The present invention relates to a method of manufacturing plastic film capacitors. More particularly it relates to a method of manufacturing plastic film capacitors by impregnation of the plastic film using an amine based epoxy as an impregnant which during impregnation is in liquid state and which after impregnation converts to solid state mere by improving the breakdown voltage and insulation resistance consequently increasing life expectancy on account of ability to handle high voltage surges when capacitors are used for the intended purpose.
Prior art:
Wherever improvement in voltage withstand capacity is required in capacitors, impregnation process by oil, gas, amide base aromatic liquids, aromatic hydrocarbon liquid or amide base epoxide with or without vacuum, is used, often leading to:
1. Gas leakage
2. Oil oozing out
3. Degradation of voltage, after use
4. Degradation of insulation resistance, after use
Japanese patent JP9213564 relates to a capacitor which is impregnated with electric insulating oil composed of olefin Oligomor, an aromatic group hydrocarbon having at least three benzene rings. As to olefin Oligomor content of fraction whose molecular weight is almost 500 is less man or equal to 7wt %,(to olefin Oligomor of lOOwt %), and content of fraction whose molecular weight is at most 400 is

less man or equal to 7wt%, The above olefin Oligomer of 5-95wt%, is mixed with electrically
t
insulating oil of 100wt% for impregnation. The aromatic group hydrocarbon to be mixed with olefin Otigomor has at least three benzene rings. The above aromatic group hydrocarbon of 95-10wt % is mixed based on 100 % of the electrically insulating oil for insulation.
US patent 5384684 relates to Metallised plastic film capacitor. It teaches about capacitor comprising a metallised plastic film impregnated with an electrically insulating oil composition, said composition comprising 5% to 10 % by weight ,bascd on the total weight of the composition, of a natural fatty acid triglyceride containing less than 10 % by weight of a fatty acid ester having three hydroxyl radicals and the remainder of the composition being an aromatic hydrocarbon .liquid at -30 °C,
Canadian patent CA2467290 relates to an invention which provides an all-film oil- impregnated capacitor in which the dielectric layers consists only of a plastic resin film such as a biaxially oriented poly propylene resin film (OPP) suitable for use in microwave ovens. The all film capacitor of the invention can be obtained and has satisfactory propeities only when prepared by using specified materials including the OPP film, aluminum foil and capacitor oil and under specified conditions relative to me dielectric tangent values and dielectric capacity values before and after impregnation with a capacitor oil as well as the conditions in the steps of oil impregnation.
US patent 4117579 relates to metallised plastic film capacitor. It briefly explains about impregnation of capacitor by using epoxide. According to this US patent between about 0.01 and 10.0% by weight of an antioxidant, and between about 0.1 and 10% by weight of an epoxide are added to a liquid aromatic ester prior to refining or purification of me ester and prior to use of me ester

US" patent 5719742 discloses a metallised plastic film capacitor which is impregnated with an electrically insulating oil composition comprising 10 to 95 % by weight of an aromatic hydrocarbon having at least 3 benzene rings and 90 to 5 %by weight of an olefin oligomer containing 7 % by weight or less of a fraction having molecular weight of 500 or less and 2 % by weight or less of a fraction having a molecular weight of 400 or less,
US patent 4598335 discloses impregnated wound capacitor comprises dielectric strips which consists at least partially of plastic foils swelled by the impregnant The electrodes of regenerabty thin metal layers are connected at the end faces of the capacitor coil with end contact layers. Impregnation holes are arranged in the dielectrically active part of the coil such mat me maximum spacing between successive holes on the capacitor surface is equal to R=r.sqroot3, where r is the impregnation reach.
All the above prior art systems discuss regarding impregnation of a capacitor and do not disclose disadvantages such as swelling and aggravation of plastic films due to amide based epoxide and aromatic hydrocarbon compound, which affect and weaken the dielectric strength leading to deterioration of capacitance value, and/or insulation resistance.
A plastic film capacitor completely fails or its capacitance value defoliates due to surges encountered during its usage because of the design, and / or process and / or impregnant used. Because of non impregnation and/ or impregnation with any impregnant disclosed in the prior art, it is observed that the failure of the plastic film capacitor occurs.
Hence it is necessary to overcome the above drawbacks of the prior art and to provide plastic film capacitors that overcome all the above mentioned drawbacks of the prior art systems.

Objective of the invention:
The objective of the present invention is to provide improved plastic film capacitors, which eliminate the above said drawbacks associated with the prior art system.
Anolher objective of the present invention is to impregnate a plastic film capacitor with an amine based epoxy as an impregnant that during impregnation is in liquid state and after impregnation converts to solid state.
Anolher objective of the present invention is to improve the breakdown voltage and insulation resistance of plastic film capacitors to increase the life expectancy despite absorbing high voltage surges when capacitors are used for the intended purpose.
Yet another objective of the present invention is to avoid swelling and aggravation of the plastic film due to amide based epoxide and aromatic hydrocarbon compound, which will affect the dielectric strength and weaken the dielectric constant leading to deterioration of capacitance value, and / or insulation resistance.
Yet another objective of the present invention is to enhance the life of the plastic film capacitors, improving their reliability by providing better high voltage withstanding capacity of capacitors.
Yet another objective of the present invention is to eliminate humming noise observed during intended use of plastic film capacitors at alternating frequency.
Yet another objective of the present invention is to provide a method of impregnating plastic film capacitors, for the intended use, having minimal intricacies during processing.

Accordingly the invented method of manufacturing plastic film capacitors comprising:
a. placing under a vacuum a plastic dielectric film and depositing a thin layer of metal alloy as an
electrodes on it;
b. winding a metallised film into a cylinder so that a metallised edge extends on each end of the
wound capacitor section;
c. Heating a wound capacitor in air ventilated oven at a temperature of 110^ for me time period of
5 hours;
d. spraying both ends with small droplets of molten metal that adhere alone & make contact with the
metallisation on the film;
e. soldering /welding the wire lead to this end sprayed metallised portion for making termination
contact;
f. preheating the capacitor coil obtained in step ( e ) by keeping in the air ventilated oven at the
temperature between 85 to 107 oC for time period of 1 to 2 hours;
g. Impregnating said preheated capacitor coils with amine based epoxy under vacuum for the period
of 10-15 minutes ; wherein said amine base epoxy contains amine base resin and hardener in the
ratio of 100:72.5 and having property of solidifying at temperature of 100 *C and said epoxy is
kept under vacuum before impregnation to remove excess air inside the said epoxy;
h. drying the said impregnated capacitor coil by keeping it in air ventilated oven at a temperature of 107°C and
i. Encapsulating and sealing dried impregnated capacitor coil Mostly capacitor coil is preheated at a temperature of 85 *C .In this method during impregnation process amine based epoxy penetrates inside the capacitor coil and fills up the air pockets thereby sealing the capacitor coil
Also there is provided a plastic film capacitor manufactured by the above mentioned method of the present invention.

Brief description of the drawings :
•
Figure 1: showing wound capacitor coil.
Figure 2: showing cross sectional area of wound capacitor coil.
Figure 3: showing wound capacitor coil with end spray metallisation.
Figure 4: showing wound capacitor coil with end spray metallisation and termination soldered.
Figure 5: shows amine based epoxy impregnated capacitor coil according to the present invention.
Figure 6: shows cross sectional area of amine base epoxy impregnated capacitor coil according to the
present invention. Figure 7: shows process flow chart of the said invented process of epoxy impregnation.
Detailed description of the invention
The above, and other objects, features and advantages of the invention will become apparent from the following description read in conjunction with the accompanying drawings.
Meaning of the reference numerals used in the drawings are as follows:
1.-Wound capacitor coil
2.- Electrodes
3.- Dielectric film
4.- End spray metallisation
5.- Lead wires
6.- Wekung/soldering contact
7.-Amine based epoxy

According to present invention, plastic film capacitors are manufactured by winding into a cylinder any dielectric plastic film and any electrode. Fig 1 shows a wounded capacitor coil(l). Fig 2 shows the cross sectional area of a wound capacitor coil(l). As shown in figure2 eletrodes( 2 ) are placed between dielectric films (3 ). After winding, capacitor coils(l) are kept in air ventilated oven for heat treatment for 5 hrs. at a temperature 110°C and then end spray metallisation( 4 ) is done for tennination contact Fig 3 shows a capacitor coil with end spray metallisation. Then the lead wires (5) are soldered / welded to the ends of the sprayed coil for inaking termination contact Figure 4 shows the wound capacitor coil with end spray metallisation and termination soldered. Tennination/ lead wires ( 5 ) and welding/soldering contacts (6) are shown in figure 4. After this these capacitor coils (1) are kept in air-ventilated oven at a temperature between 85 to 107°C for a time period 1 to 2 hours for preheating. Then the amine based epoxy ( 7) containing amine based resin and hardener in the ratio of 100:72.5 and having the property of becoming solid at temperature of 100°C is taken and said epoxy is kept under vacuum to remove air in the epoxy. The resin used in the present invention is ETH-30 and hardener used is ETRF-30. Preheated capacitor coils are men immersed in said epoxy for impregnation under vacuum for a period of 10 to 15 minutes. During the epoxy impregnation processes under vacuum, epoxy penetrates into the capacitor coil and fills up the air voids / pockets and seals the capacitor coil for protection from atmosphere and improves the breakdown voltage since air pockets odierwise damage the plastic film during its usage in field conditions. Figure 5 shows the said epoxy impregnated capacitor coil Figure 6 shows the cross sectional area of the epoxy impregnated capacitor coil After impregnation these coils are kept in an air ventilated oven at a temperature of 107 °C for drying of the said epoxy. After drying, the impregnated coils are encapsulated. Figure 7 shows me flow chart of the process of present invention as discussed in the above description of the invention.

Best mode of carrying out invention:
First a plastic dielectric film is placed in vacuum and a thin layers of metal alloy as an electrode is deposited on it Then a metallised film is wound into a cylinder so mat a metallised edge extends on each end of the wound capacitor section. Then these capacitor coils are kept in air ventilated oven for 5 hrs. for heat treatment Then both ends are sprayed with small droplets of molten metal that adhere along & make contact with the metallisation on the film. Then the wire lead is soldered/welded to this end sprayed metallised portion for making termination contact There after the capacitor coil is preheated by keeping it in air ventilated oven at the temperature of 85° C for time period of 2 Hours. Then the amine based epoxy containing amine base resin and hardener in the ratio of 100:72.5 and which having property of getting solid at temperature of 100 °C is taken and said epoxy is kept under vacuum to remove the excess air inside the epoxy. The hardener used in the present invention is ETH-30 and resin used is ETRF-30. The preheated capacitor coils are then immersed in said epoxy for impregnation under vacuum for a period of 15 minutes. During the epoxy impregnation process under vacuum epoxy will penetrate inside me capacitor coil and fillup the air pockets and seal the capacitor coil to protect from atmosphere and improves breakdown voltage since air pockets otherwise damage the plastic film during its usage in field condition. After impregnation these coils are kept in the air ventilated oven at a temperature of 107 °C for drying of said epoxy. After drying, the impregnated coils are encapsulated and sealed.

Advantages of the invention:
1. The present invention improves breakdown voltage and insulation resistance of plastic film capacitors to increase the lift expectancy on account of ability to absorb high voltage surges when capacitors are used for the intended purpose.
2. Another advantage of the present invention is to avoid swelling and aggravation of plastic due to amide based epoxide and aromatic hydrocarbon compound, which affects the dielectric strength and weakens the dielectric constant and also leading to deterioration of capacitance value.
3. Yet another advantage of the present invention is impregnation of plastic film capacitors with an amine based epoxy as an impregnant mat during impregnation is in liquid state and after impregnation converts to solid state avoiding oozing and / or leakage of the impregnant
Industrial Application:
Plastic film capacitors of the present invention are used in the electronics industry. The present invention is useful in various electronic circuits where high voltage withstanding capacity of the plastic film capacitor is required.
The present invention is not limited to the above described embodiments , and various changes may be made, if desired, widiout departing from the essence or spirit of the invention which can be read from the claims and the entire specification. All these changes are also intended to be wthin technical scope of the present invention.

claim:
. A method of manufacturing a plastic film capacitor comprising:
a. placing in vacuum a plastic dielectric film and depositing a thin layer of metal alloy as
an electrodes on it;
b. winding a metallised film into a cylinder so mat metallised edge extends on each end of
the wound capacitor section;
c. heating a wound capacitor in air ventilated oven at a temperature of 110°C for the time
period of 5 hours;
d. spraying both ends with small droplets of molten metal mat adhere along & make contact
with the metallisation on the film;
e. soldering / welding the wire lead to this end sprayed metallised portion for making
termination contact;
f. preheating the capacitor coil obtained in step (e ) by keeping it in air ventilated oven at
temperature between 85 to 107oC for the period of 1 to 2 hours;
g. impregnating said preheated capacitor coils with amine base cpoxy under vacuum for a
period of 10 to IS minutes; wherein said amine base cpoxy contains amine base resin and
hardener in the ratio of 100:72.5 and having property of getting solid at temperature of
100 *C and epoxy is kept under vacuum before impregnation to remove excess air inside
saidepoxy;
h. drying said impregnated capacitor coil by keeping it in air ventilated oven at a
temperature of 107oC; i. encapsulating and sealing dried impregnated capacitor coil

2. A method of manufacturing plastic film capacitor as claimed in claim 1 wherein capacitor coil is preheated at temperature of 85 oC.
3. A method of manufacturing plastic film capacitor as claimed in claim 1 wherein preheating of capacitor coil is done for period of 1 hour.
4. A method of manufacturing plastic film capacitor as claimed in claim 1 wherein impregnation is carried out for a period of 10 minutes.
5. A method of manufacturing plastic film capacitor as claimed in claim 1 wherein during impregnation process amine base epoxy penetrates inside the capacitor coil and fills up the air pockets and seal the capacitor coil
6. Plastic film capacitor manufactured by the method as claims in
7. A method of manufacturing plastic film capacitor as herein described with reference to accompanying drawings.
8. Plastic film capacitor as herein described with reference to accompanying drawings.
Dated this on 11th day of August 2006.
For CTR Manufacturing Industries Ltd.,

Mr.A.R Kumar Managing Director

Documents:

1272-mum-2006-abstract(16-4-2007).doc

1272-mum-2006-abstract(16-4-2007).pdf

1272-mum-2006-cancelled pages(16-4-2007).pdf

1272-mum-2006-claims(granted)-(16-4-2007).doc

1272-mum-2006-claims(granted)-(16-4-2007).pdf

1272-mum-2006-correspondence(16-4-2007).pdf

1272-mum-2006-correspondence(ipo)-(19-10-2007).pdf

1272-mum-2006-drawing(16-4-2007).pdf

1272-mum-2006-form 1(16-4-2007).pdf

1272-mum-2006-form 18(16-4-2007).pdf

1272-mum-2006-form 2(granted)-(16-4-2007).doc

1272-mum-2006-form 2(granted)-(16-4-2007).pdf

1272-mum-2006-form 3(16-4-2007).pdf

1272-mum-2006-form 9(11-8-2006).pdf

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Patent Number

211224

Indian Patent Application Number

1272/MUM/2006

PG Journal Number

45/2007

Publication Date

09-Nov-2007

Grant Date

19-Oct-2007

Date of Filing

11-Aug-2006

Name of Patentee

CTR MANUFACTURING INDUSTRIES LTD.

Applicant Address

E 1,Chikalthana, Aurangabad-431210

Inventors:

#	Inventor's Name	Inventor's Address
1	B. GOKULDAS SHENOY	CTR Mfg Ind,Ltd, E 1,Chikalthana, Aurangabad.

PCT International Classification Number

H01G4/22

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA