FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See Section 10) Rule 13
"ONE SIDE RELEASE COATED, FLAME RETARDENT, HIGH TEMPERATURE WITHSTANDING ELECTRICAL INSULATION AND HEAT DISSIPATING TAPE" AND THE PROCESS OF MANUFACTURING THE SAME
PRS Solutions Private Limited, a Company incorporated under the Companies Act, 1956
and having its office at 63, Bombay Samachar Marg, Mumbai - 400 001 Maharashtra
(d State, India, Indian.
The following specification particularly describes and- aucor-brin the nature of this
invention and the manner in which it is to be performed

FIELD OF THE INVENTION:
The invention relates to manufacturing "One Side Release Coated, Flame Retardant, High Temperature Withstanding Electrical Insulation And Heat Dissipating Tape" and the Process Of Manufacturing the Same.
DESCRIPTION OF THE PRIOR-ART:
Slot insulating tapes/ materials are available in a variety of compositions depending upon the application in coils, motors or generators. For high temperature applications, however, the range of tapes/materials available is limited to a few compositions such as plain Aramide Paper, Laminates of Aramide with films based on Polyester and Polyimide. The said tape/material are being used when the operating temperature is in the range of 155° and 180° Celsius. The materials involved in known slot liners are primarily electrically and thermally insulating in nature. Consequently, it is not possible to dissipate heat generated in the winding on to the surroundings. This results in higher winding temperature rise and consequently results in early failure of insulation.
Ceramic paper has found a wide range of applications in electrical insulation on account of its high thermal conductivity and average electrical insulating properties.
A variety of silicone rubbers are available for insulating and cushioning assemblies. Silicone rubbers exhibit a wish list of characteristics including superb chemical resistance, high temperature performance, good thermal and electrical resistance, long term resiliency and easy fabrication. Liquid silicone rubbers are available in electrical grades for conformal coating, potting and gluing. Silicone rubbers filled with conducting fillers are available for applications requiring thermal conductivity.
The use of silicone elastomer and ceramic paper combination, in manufacture of insulation tape/laminates for slot insulation has not been known till now.
SUMMARY OF THE INVENTION:
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Ceramic Paper coated on one side with a formulated silicone elastomer makes an excellent slot liner with good dielectric properties and thermal dissipation. In the present invention, an attempt has been made to prepare a "One Side Release Coated, Flame Retardant, High Temperature Withstanding Electrical Insulation And Heat Dissipating Tape". The said tape is capable of withstanding high temperatures of class 180° Celsius. On account of the flexibility in lower thickness' it also finds an application as a conducting wrapper in transformer coils. The added advantage of the tape being Flame-Retardant imparts added safety to the appliance operation.
The manufacturing of the "One Side Release Coated, Flame Retardant, High Temperature Withstanding Electrical Insulation And Heat Dissipating Tape" comprises of coating substrate as described in details hereafter, of the required construction, commensurate with the desired properties of thickness and strength, by depositing a formulated silicone elastomer as described hereafter on one side of the substrate to the extent of 60 to 150 gm per square meter. The deposition is carried out by use of known coating methods such as reverse roll coating or clearance coating in one or multiple stages followed by known drying/curing methods like blowing hot air in enclosed chamber.
The substrate can be plain calendered/hot pressed or un uncalendered ceramic paper with inorganic fillers and binders or a laminate of ceramic paper with film/s such as polyester, polyimide, polyether naphthanate, with the laminate configuration being of either two or three layers. The thickness of ceramic paper can be from 2 mil to 15 mil and mat of film can be from 1 mil (0.025mm) to 5 mil (0.125mm), though not being limited to these only.
The preparation of the formulated silicone elastomer begins with compounding two or more silicone elastomers such as No Post Cure Silicone Rubber having different hardness on a two-roll milling machine, with fillers and two or more additives including curing agents like Tin catalyst, Platinum catalyst or Benzoyl peroxide as applicable to impart the properties of flame-retardancy. The said compounded silicone elastomer is then optionally dispensed in solvent of aliphatic/aromatic nature to obtain
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consistency and flow properties required and commensurate with the coating method and equipment to be used.
The coated tape so obtained is cut to desired sizes and shapes in line with the intended application. The said tape is desired to have a thickness varying from 1 mil to 20 mil, an electrical strength of ranging from 1 to 30 kv/layer. The said tape has the following features: -
(a) Flame retardancy,
(b) High electrical insulation,
(c) Electrical anti-tracking,
(d) High-temperature withstanding capability,
(e) Water proof properties and
(f) Release property on one side.
The high temperature withstanding (Class-H or Class 180° C) product successfully passes the flame retardancy test as per Underwriters Laboratories Inc.(UL) UL 510 specification. The tape can be used at a temperature of 180° C for continuous applications and at higher temperatures for a short time. The thermal dissipating property of the tape imparts a significant lowering, to the extent of about 20%, depending on the configuration of appliance, in the winding temperature. This results in an extended life of the insulation material and in turn the appliance
The said tape finds a variety of applications involving the requirements of high temperature resistance, electrical and thermal dissipation, flame retardant property along with release property on one side enabling easy removal of coil during the removal of coil for rewinding.
The above description is given only to understand the invention rather than limiting its scope. Various modification are possible which will be evident to the persons skilled in the art which should also be considered as falling within the ambit and scope of this invention and the appended claims.
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WE CLAIM:
1. A process of manufacturing "One Side Release Coated, Flame Retardant, High
Temperature Withstanding Electrical Insulation And Heat Dissipating
Tape"comprising the following steps:
(a) coating a substrate like ceramic paper by depositing a formulated silicone
elastomer to the required extent using known coating methods such as reverse roll
coating or clearance coating in one or multiple stages, followed by drying known
methods;
(b) the coated and laminated material so obtained is cut to desired sizes and shapes to
get the tape.
2. A process of manufacturing "One Side Release Coated, Flame Retardant, High Temperature Withstanding Electrical Insulation And Heat Dissipating Tape" as claimed in Claim 1, wherein the said substrate can be plain calendered/hot pressed or uncalendered ceramic paper with inorganic fillers and binders or a laminate of ceramic paper with film/s like polyester, polyimide, polyether naphthanate, with the laminate configuration being of either two or three layers.
3. A process of manufacturing "One Side Release Coated, Flame Retardant, High Temperature Withstanding Electrical Insulation And Heat Dissipating Tape" as claimed in Claims 1 and 2, wherein the thickness of ceramic paper may vary from 2 mil to 15 mil and that of film may vary from 1 mil to 5 mil.
4. A process of manufacturing "One Side Release Coated, Flame Retardant, High Temperature Withstanding Electrical Insulation And Heat Dissipating Tape" as claimed in Claim 1, wherein the said formulated silicone elastomer consists of compounding two or more silicone elastomers on a two-roll milling machine with fillers and two or more additives including curing agents to impart the properties of flame-retardancy, the said compounded silicone elastomer is then optionally dispensed in solvent of aliphatic (like hexane)/aromatic nature (like toluene) to obtain
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consistency and flow properties required and commensurate with the coating method and equipment to be used .
5. A process of manufacturing "One Side Release Coated, Flame Retardant, High Temperature Withstanding Electrical Insulation And Heat Dissipating Tape" as claimed in Claims 1 to 4, wherein the said tape has a thickness ranging from 1 mil (0.025 mm) to 20 mil (0.50 mm) and has an electrical strength ranging from 1 to 30 kv/layer.
6. "One Side Release Coated, Flame Retardant, High Temperature Withstanding Electrical Insulation And Heat Dissipating Tape" as obtained by process as claimed in Claims 1 to 6.
Dated this 6th day of September, 2003
BHARAT S.SHAH Duly Constituted Attorney