Title of Invention	"A NOVEL LOW DENSITY EPDM BASED INSULATOR FOR CASE BONDED SOLID ROCKET MOTORS"
Abstract	The present invention relates to a formulation of polyaramid fiber and fumed silica filled EPDM (Ethylene-propylene diene terpolymer) based insulator with high filler content and method of manufacturing thereof.

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FIELD OF INVENTION The present invention relates to a formulation of polyaramid fibre and fumed silica filled EPDM (Ethylene-propylene diene terpolymer) based insulator with high filler content and method of manufacturing thereof in which polyaramid fibres and fumed silica are dispersed and immobilized in the EPDM polymer matrix for application to be used as insulator for case bonded solid rocket motors utilizing HTPB based composite propellants. PRIOR ART AND BACKGROUND: In general, Solid Rocket Motors typically include an outer case or shell housing a solid propellant grain. The rocket motor case is conventionally manufactured from a rigid, yet durable material such as steel or fiber reinforced composite. The propellant is housed within the case and is formulated from a composition designed to undergo combustion, and thereby produce the requisite thrust for attaining desired rocket motor propulsion. During operation, a heat-insulating layer protects the rocket motor case from heat and particle streams generated by burning propellant. The insulator also facilitates the establishment of adhesion between the propellant and the walls of the case. It is crucial that this insulation composition withstands extreme conditions experienced during propellant combustion and protects the case from hot gases and flame. The insulator should have high tensile strength and elongation to absorb the mechanical stresses induced during manufacture, storage and flight. The insulator should also have excellent peel strength with respect to propellant. It is also crucial that it should form strong adherent char on propellant burning and have low erosion rate. Requirement of low-density insulator is mandatory to reduce the inert weight of the propulsion system. The insulator should possess good green strength so that it remains sufficiently pliable, without becoming fully cured, until used by its application in rocket motor casing. The insulator should have sufficient shelf life required for defence applications. In the past, attempts have been made to produce insulating materials based on filled and unfilled rubbers and plastics. However, these insulation systems suffer from following disadvantages/limitations. Ihe tilled and unfilled plastics such as phenolic resins, epoxy resins, high temperature melamine formaldehyde coatings, ceramics, polyester resins, etc., crack or blister as a result of rapid temperature and pressure fluctuation experienced during combustion of propellant and thus cannot be used as insulator material. Nitrile rubber used as insulation system for rocket motor suffers from disadvantages like limited shelf life due to and relatively higher density. US 4,501,841 discloses an elastomenc insulation material for rocket motors, which comprises base polymer EPDM with third monomer as Hexadiene (HD) or polychloroprene or chlorosulfonated polyethylene, fibrous filler-polyaramide and particulate hydrated silica. Thus produced elastomeric insulator composition having tensile strength 112 kg/cm2 and elongation percentage 30 %. US 4878 431 discloses an elastomeric insulating materials for rocket motors which comprises primary polymer-EPDM with NORDEL 140 contains HD as third monomer peroxy crosslinking agent. Thus manufactured elastomeric composition having tensile strength 70-166 kg/cm2, elongation percentage 10-40 % and density is 0.035-0.050 lb/inch3. US 2004/0229989 Al teaches an elastomeric insulating composition for a solid propellant rocket motor, said composition comprises base polymer-EPDM, liquid EPDM, polyaramide fiber and other additives. The composition having tensile strength 85-140 kg/cm2, elongation 50 to 125 %, rate of erosion 0.095 mm/s, density 1.140 -1.210 g/cc and thermal conductivity is 0.227 to 0.238 kcal/mh°C. EPDM have been found to be the most promising, particularly because of its characteristics like low density, low ablation rate, superior bonding characteristics, excellent low temperature and ageing properties. But the ablative properties of elastomers are not adequate for rocket motor operation. In view of this, the elastomer should be reinforced with suitable fillers. EPDM rubber reinforced with precipitated silica, hydrophobized silica and partly filled fibrous fillers such as asbestos, carbon and aramid fiber are used as insulation system for case bonded solid rocket motors. These insulation systems suffer from following disadvantages. EPDM rubber reinforced with asbestos fibers during the processing stages is injurious to health and is a health hazard, as asbestos is highly toxic in nature. EPDM rubber reinforced with precipitated silica absorbs moisture, as silica particles are hydrophilic in nature. The high moisture content in a rocket motor insulation adversely affects bonding characteristics of the insulation, and can lead to poor peel strength at insulation-to-casing and/or insulation-to-liner bond interface. Yet another disadvantage of EPDM insulation reinforced with silica particles is that, it has nearly 5% moisture content. This leads to prior control of moisture for silica and needs proper dry cycles, which prolongs the processing. Still another disadvantage of EPDM insulation reinforced with silica particles is that, this type of system needs a proper control of moisture on the place of processing and also increases the processing costs. EPDM based insulation system reinforced only with polyaramid pulp has disadvantage of very low elongation (10 - 60%) against a requirement of minimum 600% elongation to reliably absorb the mechanical stresses induced during handling, transport, storage and flight. Yet another disadvantage of EPDM based insulation system reinforced only with the polyaramid pulp is the inability of fibrous filler to get homogenously distributed in the elastomeric composition, which results in non-uniform ablative rates. EPDM based insulation system reinforced with carbon fibre has a limitation of fragility of fibres during incorporation into the elastomeric composition. Still another disadvantage of EPDM based insulation system reinforced with carbon fibre is the use of solvent processing technique. This technique has several drawbacks like the requirement of removal of solvent from the formulation, which leads to blister formation and safety issues associated with the disposal of hazardous volatile organic solvents. Yet another disadvantage of EPDM based insulation system reinforced with carbon fiber alone or part replacement with hydrophobized silica in the art is that the composition contains D per cent by weight 01 volatile solvents that aie lelanvely nazamous, compaieu to the conventional method. Still another disadvantage of EPDM based insulation system reinforced with the carbon fibre composition is that it uses nearly 80 - 100 phr of low viscosity EPDM (liquid EPDM) which drastically reduces the tensile strength and % elongation of the rocket motor insulator. EPDM based insulation system with the base polymer of EPDM containing 1,4 hexadiene as termonomer has a disadvantage of slow curing, and hence has become obsolete. NEED FOR PRESENT INVENTION In view of the foregoing limitations of insulators based on EPDM, there is a need for an EPDM based insulator formulation reinforced with reduced amount of polyaramid pulp partly along with the suitable reinforcing filler like with fumed silica, and preferably a solvent less process with distributive and homogenized mixing of fiber in the polymeric matrix to obtain an insulator with excellent mechanical properties, low density, high thermal resistant, superior peel strength properties and safe processing conditions. OBJECTIVE OF THE INVENTION: The primary objective of the present invention is to provide an insulation system for rocket motors based on composite propellant containing HTPB as a binder. Yet another objective of present invention is to provide a high strength EPDM based insulation system partly reinforced with polyaramid pulp and fumed silica. Still another objective of the present invention is to provide low density EPDM based insulation system so as to reduce the inert weight of the propulsion system. Yet another objective of present invention is to provide an EPDM based insulation system with enhanced peel strength to have an excellent bond between the propellant and the insulator. Still another objective of the present invention is to provide a high thermal resistant EPDM based insulator system thereby improving its ability to protect the motor case during storage under adverse conditions and combustion of propellant. Yet another objective ot present invention is to provide a very low erosion rate bFJJM based insulation system. Still further objective of the present invention is to provide a three stage mixing method for homogenized dispersion of polyaramid fiber pulp in the EPDM matrix. Yet further objective of the present invention is to provide a solvent less process for the incorporation of fiber pulp in the EPDM polymeric matrix. Still further objective of the present invention is to provide a distributive mixing process without any complication arising out of fragility of fibers. Yet another objective of present invention is to provide a EPDM based insulation system with the 24 hours maturation period in each stage of the three stage mixing. Still further objective of the present invention is to provide a reproducible EPDM based insulation system for application in case bonded solid rocket motors. STATEMENT OF THE INVENTION Accordingly, the present invention relates to an elastomeric insulating composition comprising: a. 50 phr to 130 phr of a solid ethylene-propylene diene terpolymer rubber; b. 10 phr to 70 phr of liquid ethylene-propylene diene terpolymer; c. 30 phr to 50 phr of fumed silica, d. 5 to 20 phr of fibrous filer, e. 1 phr to 2.0 phr of vulcanizing agent, f. 0.5 phr to 1.5 phr of Mercaptobenzthiazole (MBT), g. 1 phr to 2.0 phr of Tetramethyl thiuram disulphide (TMTD), h. 5 phr to 20 phr of tackifier, i. 0.5 to 20 phr of additives. Also, the present invention relates to a method of preparing said elastomeric insulating composition, said method comprising the step of: a) mixing a primary polymer EPDM and secondary polymer in a ratio in the range of 1:10 to 10:1 in a rolling mill, adding fibrous filler polyaramid pulp and filler fumed silica part by part along with rubber oil and bonding agent to the nip of rolling mill and mixing is carried out up to 15 minutes at normal temperature and pressure, adding one or more activators to the nip of rolling mill for a time period of 5 to 7 minutes, adding additives along with tackifier to the rolling mill nip for 5 to 10 minutes and obtaining a dough having mooney viscosity in the range of 80 to 2000 MU, keeping the dough for 24 hours and allowing the same for dispersion and polymer filler interaction, adding one or more accelerator one after another to the rolling mill nip and mixing is carried for 5 to 15 minutes for obtaining final dough, g) calendaring the said dough in order to obtain a sheet of uniform thickness, h) curing the said sheet by adding curing agent and heating at a temperature in the range of 150°C to 200°C for a time period for 10 to 20 minutes to obtain a desired elastomeric insulator sheet. SUMMARY OF THE INVENTION The present invention describes the formulation and processing technique of a novel low density EPDM based insulation for application in case bonded solid rocket motors. The EPDM based insulator formulation is prepared from filler partly containing polyaramid fibre pulp and fumed silica with sulfur curatives. According to the present invention, there is provided an EPDM based insulation formulation, which utilizes the advantage of both the fibrous and particulate filler systems. The combination of the above filler system enhances the thermal insulation properties leading to a system with low thermal conductivity, low erosion rate, high specific heat and reduced inert weight of the propulsion system by reducing the density of the insulation without adversely affecting the mechanical properties of the insulator system. The polarity of EPDM matrix is increased by the polar nature of polyaramid pulp. This results in enhanced peel strength of the insulator and improves the bonding between the propellant and insulator. Fumed silica featuring low particle size and negligible moisture content does not require any dry cycles for moisture removal. The above qualities of silica induce an excellent reinforcement. As a result, superior mechanical properties are achieved. The proposed insulator formulation, utilizes a low viscosity Liquid EDPM for homogenized dispersion of polyaramid fiber pulp. BRIEF DESCRIPTION OF TABLES Table 1 shows the Rheological properties of compound EPDM. Table 2 shows the Physical properties of compound EPDM. DETAIL DESCRIPTION OF TABLES Table 1 shows the Rheological properties of EPDM /HYPALON blend. The present invention is substantially described herewith reference to the following examples, wherein the various composition and method of preparing the composition are explained. However, it should not be construed to limit the scope of invention. DETAIL DESCRIPTION OF INVENTION Accordingly, the present invention relates to an elastomeric insulating composition comprising: 50 phr to 130 phr of a solid ethylene-propylene diene terpolymer rubber; 10 phr to 70 phr of liquid ethylene-propylene diene terpolymer; 30 phr to 50 phr of fumed silica, 5 to 20 phr of fibrous filer, 1 phr to 2.0 phr of vulcanizing agent, f) 0.5 phr to 1.5 phr of Mercaptobenzthiazole (MBT), g) 1 phr to 2.0 phr of Tetramethyl thiuram disulphide (TMTD), h) 5 phr to 20 phr of tackifier, i) 0.5 to 20 phr of additives. In one embodiment of the present invention wherein the said ethylene-propylene diene terpolymer rubber is in the range of 50 phr to 90 phr Yet another embodiment of the present invention, wherein the said liquid ethylene-propylene diene terpolymer is in the range of 10 to 50 phr In yet another embodiment of the present invention, wherein the fumed silica are selectetd from the group comprising AEROSIL 200, 130, 300 and pyrogenic silica. Yet another embodiment of the present invention, wherein the additives are selected from a group comprising one or more activator, anti-oxidants, bonding agent, rubber oil, flame retardant and accelerators. In yet another embodiment of the present invention, wherein the additives are selected from activator, bonding agent, rubber oil, flame retardant and accelerators in the range of 0.5 to 20 phr. Still another embodiment of the present invention, wherein the bonding agent is selected from a group comprising Polyethylene glycol, Diethylene glycol and Polypropylene glycol. Yet another embodiment of the present invention, wherein the flame retardant is selected from a group comprising antimony trioxide, Zinc Borate, Sodium metaborate and Ammonium di-hydrogen phosphate. Yet another embodiment of the present invention, wherein the accelerators are selected from a group comprising Tetramethyl thiuran disulphide (TMTD), Tetraethyl thiuram disulphide (TETD), Dibenzthiazyldisulphide (MBTS) and Zincmercaptobenzthiozole (ZMBT). Yet another embodiment of the present invention, wherein the tackifier is selected from group comprising wingtack, coumarone, indene, wingtack extra and terpenephenol resin. A further embodiment of the present invention, wherein the said elastomeric insulating composition having tensile strength in the range of 100 to 400 kgf/cm2, elongation percentage 425 to 1000, density 0.5 to 3.50 g/cc, hardness shore A is 70 to 90, thermal conductivity is 0.110 to 0.330 W/m°K, rate of erosion is 0.010 to 0.090 mm/sec and peel strength 1.10 to 3.70 kg/cm. Yet another embodiment of the present invention, wherein the said elastomeric insulating composition having tensile strength in the range of 150 to 300 kgf/cm2, elongation percentage 600 to 800, density 1.0 to 1.50 g/cc, hardness shore A is 70 to 80, thermal conductivity is 0.170 to 0.190 W/m°K, rate of erosion is 0.050 to 0.070 mm/sec and peel strength 1.10 to 1.70 kg/cm. A further another embodiment of the present invention relates to a method of preparing said elastomeric insulating composition, said method comprising the step of: mixing a primary polymer EPDM and secondary polymer in a ratio in the range of 1:10 to 10:1 in a rolling mill, adding fibrous filler polyaramid pulp and filler fumed silica part by part along with rubber oil and bonding agent to the nip of rolling mill and mixing is carried out up to 15 minutes at normal temperature and pressure, adding one or more activators to the nip of rolling mill for a time period of 5 to 7 minutes, adding additives along with tackifier to the rolling mill nip for 5 to 10 minutes and obtaining a dough having mooney viscosity in the range of 80 to 2000 MU, keeping the dough for 24 hours and allowing the same for dispersion and polymer filler interaction, adding one or more accelerator one after another to the rolling mill nip and mixing is carried for 5 to 15 minutes for obtaining final dough, g) calendaring the said dough in order to obtain a sheet of uniform thickness, h) curing the said sheet by adding curing agent and heating at a temperature in the range of 150°C to 200°C for a time period for 10 to 20 minutes to obtain a desired elastomeric insulator sheet. Yet another embodiment of the present invention wherein in step (a), the ratio of primary polymer to secondary polymer is in the range of 1:10 to 10:1. Yet another embodiment of the present invention wherein in step (b), the fibrous filler polyaramid pulp, fumed silica, rubber oil and bonding agents are added in the range of 30 to 50 phr, 5 to 20 phr and 1 to 3.0 phr of primary polymer respectively. Yet another embodiment of the present invention wherein in step (c), the activators are selected from the group comprising zinc oxide and stearic acid. Yet another embodiment of the present invention wherein in step (c), the activators are added in the range of 1 to 6 phr. Still another embodiment of the present invention wherein in step (d), the additives are flame retardant, coloring agent and antioxidant which are added in the range of 0.5 to 5 phr. Yet another embodiment of the present invention, wherein in step (f), the antioxidant are selected from the group comprising trimethyldihydroquinoline, styrenated phenol and ocylated diphenylamine. Yet another embodiment of the present invention, wherein in step (g), the calendaring is carried out by keeping a nip gap of mixing mill in the range of 1 to 5 mm. Yet another embodiment of the present invention, wherein in step (h), the curing agents sulfur is added in the range of 0.5 to 5 phr. Still another embodiment of the present invention relates to an elastomeric insulator made of said composition. The composition of the formulation required for the EPDM based insulation system is provided as follows with parts per hundred-rubber ratio. (Table removed) According to the present invention, the process for preparing fiber filled EPDM based insulator system for case bonded solid rocket motors comprises the following steps: A) RAW MATERIAL PREPARATION: The base polymer EDPM containing ethylidene norbornene as a termonomer with an ethylene content of 50 - 55% and Mooney Viscosity of 40-45 MU is cut into small pieces. The fibrous filler used such as polyaramid pulp (TWARON) is dried in an electric oven at 100°C for a period of minimum 2 hours to reduce the moisture level ( B) MIXING: The raw polymer, EPDM is softened by mechanical work, termed mastication by laboratory two roll rubber mixing mill. The nip of the mixing mill is adjusted to 1 to 2 mm to soften and make a band of Liquid EPDM (Molecular weight: 6500 - 8500) around the front roll. The fibrous filler polyaramid pulp is added into the nip slowly, and any material that falls into the tray underneath the rolls is returned to the nip until it is incorporated into the Liquid EPDM. After the homogenized distribution of fibers into the Liquid EPDM, the premasticated EPDM (base polymer) is added to the nip and rolled until homogenized band is formed. i) FIRST STAGE: ADDITION OF FILLER The reinforcing filler fumed silica (AEROSIL 200) is added to the nip part by part. Half the part of the fumed silica is added with the rubber oil. Another part is added with the bonding agent PEG 400. Cross mixing is carried out for 10 minutes using the doctor blade until homogenized distribution of filler occurs in the polymeric matrix. Next, the dough is kept for 24 hours to allow enough dispersion and subsequent polymer - filler interaction. ii) SECOND STAGE: The activators zinc oxide and stearic acid are added to the nip and rolled for 5 minutes. Flame retardant antimony trioxide, filler cum colouring agent talc and the antioxidant TDQ are added to the nip and again rolled for 5 minutes. Next, wingtack (tackifier) is added and rolled for 5 minutes. The dough is kept for 24 hours for good dispersion of the added chemicals. At the end of second stage, the dough is characterized in Mooney viscometer MV 2000 for Mooney viscosity. iii) THIRD STAGE: After 24 hours of dispersion, the curative package such as accelerators TMTD (ultra fast) and MBT (medium fast) are added one by one and rolled for 5 minutes. Next, vulcanizing agent, sulfur is added to the nip. The dough is rolled for 5-10 minutes for complete distribution of curatives. At the end of this stage, the final dough is characterized in Oscillating Disc Rheometer ODR 2000 for optimization of curing time and temperature as well as in Mooney viscometer MV 2000 for scorch time. iii) SHEET PREPARATION: The nip of the roll mill is adjusted to 2.5 to 3 mm to obtain a calendared sheet of uniform thickness. D) CURING: Finally, the unvulcanized insulator sheet is cured in a hand press with heated mold. The optimized curing temperature and time is 160 - 170 °C for 10 - 20 minutes. At the end of the process, these sheets are characterized for Tensile Strength, (150 - 170 kg/cm2), Elongation (650 - 700 %), Density (0.5 - 1.05 g/cm3) Hardness (82 - 84), Thermal Conductivity (0.163-0.171 W/m°K), Rate of erosion (~ 0.06 mm/sec) and Peel strength (1.3-1.5 kg/cm). The present invention is substantially described herewith reference to the following examples, wherein various composition and method of preparing the composition are explained. However, it should not be construed to limit the scope of invention. WORKING EXAMPLE 1/EXAMPLE 2/EXAMPLE 3: Composition of the individual constituents needed for ~ 1 kg of insulation system are given below: Ingredients of the EPDM Insulator (All ingredients are in grams) EPDM - 420/480/540 LIQUID EPDM - 180/120/60 AEROSIL200 - 210 TWARON - 30 ZINC OXIDE - 30 STEARIC ACID - 6 PEG 400 - 6 RUBBER OIL - 60 ANTIMONY TRIOXIDE - 6 TALC - 6 TDQ - 6 SULFUR - 9 MBT - 3 TMTD - 9 Wingtack95 - 60 A general process of preparation of insulation system is described as follows. 420/480/540 g of EPDM is premasticated in laboratory two-roll rubber mixing mill (Diameter 6"X length 15"). 180/120/60 g of liquid EPDM is weighed and loaded into the nip of the roller, which is adjusted to 1 - 2 mm. 30 g of polyaramid fibre pulp is added to the nip part by part and rolling operation is carried out until homogenized distribution of fiber with polymer matrix takes place. Then premasticated 420/480/540 g of EPDM is added around the nip. After uniformly distributed formation of band around the nip, 210 g of fumed silica is added in two installments. Approximately, half of the fumed silica is added to the nip with 30 g of rubber oil. Second installment of fumed silica is added with another 30 g of rubber oil and 6 g of PEG. This dough is cross-mixed for nearly 10 minutes and this is kept for 24 hours for dispersion of filler in the polymer and to have enough polymer-filler interaction. After 24 hours, as a second stage addition, 30 g of zinc oxide and 6 g of stearic acid are added to the nip and dough rolled for 5 minutes until complete distribution. Next, 6 g of antimony trioxide, 6 g of TDQ and 6 g of talc are added to the nip and rolled for 5 minutes. Next 60 g of wing tack 95 is added and rolled for 5min until complete distribution. At the end of this stage, the Mooney viscosity is measured as 62.5/78.1/93.6 MU by Mooney viscometer, MV 2000. After 24 hours of dispersion, the above mixed dough is formed as band around the roller. Then 9 g of TMTD and 3 g of MBT are added to the nip and rolled for 5 min. At last 9 g of sulphur is added to the nip. The dough is mixed for 5 minutes for complete distribution of curative chemicals. Then the sheet is calendared through a rubber mill to obtain desired insulator material in the form of 2.5 to 3 mm thick rubber sheet. Sample (~ 150 g) of final mixed dough is tested for Mooney scorch in MV 2000 and optimized for curing time and temperature in Oscillating Disc Rheometer ODR 2000. The properties of the dough thus prepared are as follows: Table: 1 Rheological Properties of Compounded EPDM (Table removed) Mooney viscosity values show that the compounded batch can be shaped without difficulties for further operations such as extrusion, laying in motor case etc., Mooney scorch values show that the batches have very good scorch control for complete processing operations. ODR results confirm the optimum curing time of 18.47/19.03/19.18 minutes with enough scorch safety with scorch time of 2.10/2.41/2.40 minutes at 160°C. The sheets are cured in a compression molding press for time and temperature estimated from ODR. The insulator sheets thus formed are studied for mechanical, thermal and interface properties. And the results are summarized below: Table: 2 Physical properties of compounded EPDM (Table removed) ADVANTAGE OF INVENTION The present insulator formulation provides high strength EPDM based insulation system partly reinforced with polyaramid pulp and fumed silica. Still another advantage of the present invention is to provide low density EPDM based insulation system so as to reduce the inert weight of the propulsion system. Yet another advantage is to provide an EPDM based insulation system with enhanced peel strength to have an excellent bond between the propellant and the insulator. Still another advantage is to provide a high thermal resistant EPDM based insulator system thereby improving its ability to protect the motor case during storage under adverse conditions and combustion of propellant. Yet another advantage is to provide a very low erosion rate EPDM based insulation system. Still further advantage is to provide a three stage mixing method for homogenized dispersion of polyaramid fiber pulp in the EPDM matrix. Yet further advantage is to provide a solvent less process for the incorporation of fiber pulp in the EPDM polymeric matrix. Still further advantage of the present invention is to provide a distributive mixing process without any complication arising out of fragility of fibers. Yet another advantage of is to provide a EPDM based insulation system with the 24 hours maturation period in each stage of the three stage mixing. Still further advantage of the present invention is to provide a reproducible EPDM based insulation system for application in case bonded solid rocket motors. WE CLAIM: 1. An elastomenc insulating composition comprising: a) 50 phr to 130 phr of a solid ethylene-propylene diene terpolymer rubber; b) 10 phr to 70 phr of liquid ethylene-propylene diene terpolymer; c) 30 phr to 50 phr of fumed silica, d) 5 to 20 phr of fibrous filer, e) 1 phr to 2.0 phr of vulcanizing agent, f) 0.5 phr to 1.5 phr of Mercaptobenzthiazole (MBT), g) 1 phr to 2.0 phr of Tetramethyl thiuram disulphide (TMTD), h) 5 phr to 20 phr of tackifier, i) 0.5 to 20 phr of additives. 2. The elastomeric composition as claimed in claim 1, wherein the said ethylene-propylene diene terpolymer rubber is in the range of 50 phr to 90 phr. 3. The elastomeric composition as claimed in claim 1, wherein the said liquid ethylene-propylene diene terpolymer is in the range of 10 to 50 phr. 4. The elastomeric composition as claimed in claim 1, wherein the fumed silica are selectetd from the group comprising AEROSIL 200, 130, 300 and pyrogenic silica. 5. The elastomeric composition as claimed in claim 1, wherein the additives are selected from a group comprising one or more activator, anti-oxidants, bonding agent, rubber oil, flame retardant and accelerators. 6. The elastomeric composition as claimed in claim 5, wherein the additives are selected from activator, bonding agent, rubber oil, flame retardant and accelerators in the range of 0.5 to 20 phr. 8. The elastomeric composition as claimed in claim 1, wherein the bonding agent is selected from a group comprising Polyethylene glycol, Diethylene glycol and Polypropylene glycol. the flame retardant is selected from a group comprising antimony trioxide, Zinc Borate, Sodium metaborate and Ammonium di-hydrogen phosphate. 9. The elastomeric composition as claimed in claim 1, wherein the accelerators are selected from a group comprising Tetramethyl thiuran disulphide (TMTD), Tetraethyl thiuram disulphide (TETD), Dibenzthiazyldisulphide (MBTS) and Zincmercaptobenzthiozole (ZMBT). 10. The elastomeric composition as claimed in claim 1, wherein the tackifier is selected from group comprising wingtack, coumarone, indene, wingtack extra and terpenephenol resin. 11. The elastomeric composition as claimed in claim 1, wherein the said elastomeric insulating composition having tensile strength in the range of 100 to 400 kgf/cm , elongation percentage 425 to 1000, density 0.5 to 3.50 g/cc, hardness shore A is 70 to 90, thermal conductivity is 0.110 to 0.330 W/m°K, rate of erosion is 0.010 to 0.090 mm/sec and peel strength 1.10 to 3.70 kg/cm. 12. The elastomeric composition as claimed in claim 11, wherein the said elastomeric insulating composition having tensile strength in the range of 150 to 300 kgf/cm , elongation percentage 600 to 800, density 1.0 to 1.50 g/cc, hardness shore A is 70 to 80, thermal conductivity is 0.170 to 0.190 W/m°K, rate of erosion is 0.050 to 0.070 mm/sec and peel strength 1.10 to 1.70 kg/cm. 13. A method of preparing an elastomeric insulating composition as claimed in claim 1, said method comprising the step of: a) mixing a primary polymer EPDM and secondary polymer in a ratio in the range of 1:10 to 10:1 in a rolling mill, b) adding fibrous filler polyaramid pulp and filler fumed silica part by part along with rubber oil and bonding agent to the nip of rolling mill and mixing is carried out up to 15 minutes at normal temperature and pressure, c) adding one or more activators to the nip of rolling mill for a time period of 5 to 7 minutes, d) adding additives along with tackifier to the rolling mill nip for 5 to 10 minutes and obtaining a dough having mooney viscosity in the range of 80 to 2000 MU, e) keeping the dough for 24 hours and allowing the same for dispersion and polymer filler interaction, f) adding one or more accelerator one after another to the rolling mill nip and mixing is carried for 5 to 15 minutes for obtaining final dough, g) calendaring the said dough in order to obtain a sheet of uniform thickness, h) curing the said sheet by adding curing agent and heating at a temperature in the range of 150°C to 200°C for a time period for 10 to 20 minutes to obtain a desired elastomeric insulator sheet. 14. The method as claimed in claim 13 wherein in step (a), the ratio of primary polymer to secondary polymer is in the range of 1:10 to 10:1. 15. The method as claimed in claim 13 wherein in step (b), the fibrous filler polyaramid pulp, fumed silica, rubber oil and bonding agents are added in the range of 30 to 50 phr, 5 to 20 phr and 1 to 3.0 phr of primary polymer respectively. 16. The method as claimed in claim 13 wherein in step (c), the activators are selected from the group comprising zinc oxide and stearic acid. 17. The method as claimed in claim 13 wherein in step (c), the activators are added in the range of 1 to 6 phr. 18. The method as claimed in claim 13 wherein in step (d), the additives are flame retardant, coloring agent and antioxidant which are added in the range of 0.5 to 5 phr. 19. The method as claimed in claim 13 wherein in step (f), the antioxidant are selected from the group comprising trimethyl dihydroquinoline, styrenated phenol and ocylated diphenylamine. 20. The method as claimed in claim 13 wherein in step (g), the calendaring is carried out by keeping a nip gap of mixing mill in the range of 1 to 5 mm. 21. The method as claimed in claim 13 wherein in step (h), the curing agents sulphur is added in the range of 0.5 to 5 phr. The elastomeric insulator made of composition as claimed in claim 1. 23. An elastomeric insulating composition, a method of preparing the same and elastomeric insulator made of said composition substantially as herein described with reference to the accompanying examples.

Documents:

3467-del-2005-Abstract-(05-09-2013).pdf

3467-del-2005-abstract.pdf

3467-del-2005-Claims-(05-09-2013).pdf

3467-del-2005-claims.pdf

3467-del-2005-Correspondence Others-(05-09-2013).pdf

3467-del-2005-correspondence-others.pdf

3467-del-2005-correspondence-po.pdf

3467-del-2005-description (complete).pdf

3467-del-2005-form-1.pdf

3467-del-2005-form-18.pdf

3467-del-2005-Form-2-(05-09-2013).pdf

3467-del-2005-form-2.pdf

3467-del-2005-form-26.pdf

3467-del-2005-form-3.pdf

3467-del-2005-form-5.pdf