Mica tape for fire resistant cables is made of mica paper ( fluorophlogopite, phlogopite or calcined muscovite mica paper ) and glass cloth ( or polyethylene film ) with small-amount of high heat resistance silicone adhesive. This tape is dry, non-adhesive and flexible. The end product has tensile strength for speed winding. Phlogopite mica tape has good electical insulation, the typical temperature is 840-950°C, and for fluorophlogopite mica type is 1000-1200°C. The end product is made with single layer of glass cloth for mica content over 70%. But, According to requirement of consumer, The mica tape can also be made with both sides of glass cloth.
Properties of F Mica Tape:
1. F mica tape is a unique flame resistant material.
2. Fluorophlogopite mica tape-covered electric cables will maintain circuit intergrity when exposed to flames, at temperatures of up to 1200°C for 3h.
3. When over heat because of electric accident, F mica tape-covered electric cables entirely will not fire for short circuits.
4. The use of F mica tape limits the amount of thermo plastic material needed in cable construction, thereby reducing the volume of toxic smoke and gases emitted and delays the emission of toxic fumes during a fire.
5. F mica tape is non toxic, It's impermeable to water and has good resistance to acid, alkline, corona and radiation.
6. It's entirely non-combustible and high heat resistant.
The outstanding properties of F mica tape make it ideal for use in: power cables, command cables, signal and control cables, appliance wiring, high temperature cables and fire resistant wiring and cables. F insulated cable are widly used on ships and off-shore platforms and in tunuels, steelworks, unclear power plants and so on.
Example of Application For Mica Tape:
F mica tape can be applied directly over the copper conductor, normal application, reference must be made to the structural condition of electric cable or electric wire, overlap wrapping can range from 20% to 50%. F mica tape can also be applied directly over a bundle of conductors, this format of application prevent direct contact of the heated PVC material with air resulted in improved insulation and heat resistance as well as prolong the useful life of the conductor. Other F mica tape is extremly make it applicable to the rectangular copper wrie for electrical purposes, the end product is extremely insulative and heat.
1. Conductor 2. Fire Resistant Layer 3. Insulation (XLPE or PE) 4. Filler 5. Binder Tape 6. Sheath(Polyolefin of low smoke, low toxic non-halegon)
The High Heat Resistance Of Fluorolpite Mica:
Muscovite mica [KAL2(ALSi3O10)(OH)2] and Phlogopite mica [KMg3(ALSi3O10)(-OH,F)2] are natural minerals. The crystal structure of natural micas contain (-OH), which begin to decomposed at 450°C or 650°C. The theremogravimetic loss of natural mica increase suddenly and start to deteriorate at 650°C or 850°C. Fluorophlogopite, as a result fluorophlogopite can't be decomposed before melting point ( 1375°C ), fluorophlogopite can't has highest resistance of all mica. fluorophlogopite mica tape has heat resistance up to 1200°C.
The flame temperature used and duration of mica tape-insulated cables shall be selected from the the fire the following calagories of international standards:
1. Mica paper tapes for flame resistant security cable. IEC 371-3-81991
2. Fire-resisting charactentics of electric cables. IEC 331-1970
3. Proposed fist edition of the standard for test of fire resistive cable. UL2196-1995 U.S.A
4. Performace requirements for cables required to maintain circuit integrity under fire conditions. BS6387-1974 U.K.
5. Test method on electric wires or cables under fire conditions. GB-12666 6-90
6. Polyethy lene (Cross-linked polythy lene) insulated and polyvinyl chloride (polyethy lene) sheathed fire-resistant cables. CNS11359-C2167