FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See Section 10)
"Fiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash" 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 State, India.
The following specification particularly describes and ascertain the nature of this invention and the manner in which it is to be performed
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FIELD OF THE INVENTION:
The invention relates to "Fiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash" and the process of manufacturing the same.
DESCRIPTION OF THE PRIOR-ART:
Different types of tapes comprising of varities of substrates such as films, cloth etc. are used in industries for electrical insulation purpose. These tapes are available either as such in roll form or with pressure sensitive adhesive coatings. The cloth based adhesive tapes are based on backing materials like cotton cloth, rayon cloth, acetate rayon cloth, nylon cloth and fiber glass cloth. Fiber glass cloth tapes both with or without adhesives are commonly used for electrical insulation applications specially where high temperature operation is a key requirement. Pressure sensitive adhesive coated fiber glass cloth tapes are used for high temperature applications ranging from 130°C to 180°C.
Fiber Glass cloth coated with a silicone adhesive gives an adhesive tape that can be used for electrical insulation purpose having continuous operating temperature upto 180°C. But the said fibreglass cloth based adhesive coated tape does not have the property of withstanding intense heat even for short period which can be experienced in actual use due to contact with flame or molten metals. Fiber glass cloth being a woven fabric does not conducts heat as fast as solid glass, hence it fails in dissipating heat quickly. Although melting point of glass as such is about
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1120°C woven yarn losses its tensile strength at much lower temperatures. The cloth loose approximately 50% of room temperature tensile strength at 370°C and retains approximately 25% of room temperature tensile strength at 480°C. Fiber glass has a softening point of approximately 846°C and hence when such fiber glass cloth tapes come in contact with intense heat such as molten metal and/or exposed directly to flame they tend to soften and develop holes/punctures thereby causing failure in their primary function of electrical insulation.
To overcome this problem, in the present invention a formulated coating solution has been developed which when coated on the non adhesive side of adhesive coated fiber glass cloth tapes can make them suitable to withstand very intense heat and flame for short periods.
SUMMARY OF THE INVENTION:
In the present invention a pressure adhesive coated fiber glass cloth tape has been developed by providing a formulated solution coating which makes it suitable for withstanding intense heat due to falling of molten metals and/or exposure to direct flame for short periods.
The formulated solution consists of dispersion of hydrated laminar magnesium - aluminum - iron silicates in aqueous phase which has the unusual property of exfoliating when subjected to intense heat. The dispersion can be diluted to coatable consistency and texture commensurate to the coating equipment. The formulated solution is a fully oxidized non- flammable mineral which has the remarkable ability
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of being able to expand to many times its original volume when subjected to heat - a property known as exfoliation. This mineral has specific properties such as incombustibility and non- flammability. Due to its incombustible nature the coated surface can withstand up to 1100°C. The dispersion can be diluted to coatable consistency and texture commensurate to the coating equipment.
The manufacturing of the "Fiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash comprises of the formulated solution coating to the extent of 5-30 gm per square meter on one side of a woven glass fabric of the required construction, commensurate with the desired properties of thickness and strength. The coating which exfoliates on heating, is carried out by use of conventional methods in one stage followed by drying operation which is also carried out by known conventional methods.
The one side coated fabric so obtained is again coated with pressure sensitive silicone adhesive on the other side with the required weight. The said adhesive coated product is then laminated to embossed PVC or HDPE film as interliner and subsequently cut to desired shapes and sizes.
The pressure sensitive, silicone adhesive consists of silicone gum & silicone resin. The resin is used as a tackifier and its quantity is adjusted for achieving the physical properties of the pressure sensitive adhesive. The polymers are dissolved in a solvent & chemically reacted in such a fashion that condensation takes place. The condensation reaction of SiOH
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groups proceeds readily as water is removed. Before coating on the glass cloth an organic peroxide catalyst like Benzoyl peroxide or 2, 4, dichloro Benzoyl peroxide is added to silicone adhesive, to increase the cohesive strength of the adhesive, and can be diluted to coatable consistency and texture commensurate to the coating equipment.
CONSTRUCTION:

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Intense heat withstanding
formulated solution coating
Fibre Glass Cloth
Pressure sensitive Silicone
Adhesive
Embossed PVC or HDPE film liner

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WE CLAIM:
1. Fiber glass cloth tape coated with pressure sensitive adhesive for
withstanding intense heat, flame and molten splash comprises of the
following steps:-
(a) coating one side of a woven glass fabric of the required
construction with a formulated solution coating to the extent of 5-
30 gm per square meter by use of conventional coating methods
followed by drying with conventional methods;
(b) coating other side of the woven glass fabric obtained in step (a) above with silicone adhesive with required amount of catalyst and pressure sensitive silicone adhesive and thereafter laminated to embossed PVC or HDPE film as interliner by use of conventional coating methods followed by drying with conventional methods;
(c) the coated fabric so obtained is cut to desired sizes and shapes.

2. "Fiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash" as claimed in Claim 1 wherein the formulated solution coating consists of dispersion of hydrated laminar magnesium-aluminium-iron silicates
3. "Fiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash as claimed in Claim 1 wherein the woven fibre glass cloth is constructed out of 'E' class glass and having a required construction, commensurate with the desired properties of thickness and strength.
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4. Fiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash as claimed in Claim 1 wherein the silicone adhesive consists of silicone gum and silicone resin.
5. Fiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash wherein the silicone adhesive is diluted to coatable consistency and texture commensurate to the coating equipment by adding adequate quantity of aromatic solvents such as Toluene.

6. Fiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash as claimed in Claim 1 wherein the catalyst used is an organic peroxide like Benzoyl peroxide or 2, 4, dichloro Benzoyl peroxide.
7. 'Tiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash and the process of manufacturing the same as claimed in Claims 1 to 6 , by which "Adhesive coated fiber glass cloth tape for withstanding intense heat, flame and molten splash" is obtained.
Dated this 12th day of March, 2007

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ABSTRACT
Fiber glass cloth tape coated with pressure sensitive adhesive for withstanding intense heat, flame and molten splash comprises of (a) coating one side of a woven glass fabric of the required construction with a formulated solution followed by drying with conventional methods; (b) coating other side of the said woven glass fabric with pressure sensitive silicone adhesive with required amount of catalyst followed by drying with conventional method and thereafter laminated to embossed PVC or HDPE film as interliner and (c) the coated fabric so obtained is cut to desired sizes and shapes.
Dated this 12th day of March, 2007