Tape insulations are used as a primary insulation; includes TFE, Kapton, Mica, Polyester, alone or laminated with other materials, etc.
Tapes are rarely used as a primary insulation in electronic wires because such wires, as compared with those having extruded insulations, are relatively expensive. The wrapping process is slow and generally followed by a second operation to fuse the tape layers into a solid, impervious wall. Although TFE and mica insulated wires do not necessarily need to be fused, the high cost of the tapes and then the protective glass braids that are applied over the insulation are specified when no other material will meet the application requirement.
POLYESTER TAPE is not generally used as a primary insulation, but rather as shield isolation and insulation protection, and as a thermal barrier and for additional strength. DuPont's Mylar is most commonly used by our wire manufacturers. Polyester is tough, transparent and has an attractive balance of properties.
KAPTON TYPE F film is very tough. It has excellent abrasion, cut-through and impact resistance; very high resistance to weathering and all chemicals except strong bases, a -200C to +200C operating temperature range and excellent electrical properties. Kapton is radiation resistant and will not burn.
TFE TEFLON TAPE is used as a primary insulation when severe abrasion or other abuse is expected. It is resistant to chemicals, heat and moisture. TFE tapes are rated up to 260C for Mil Specs and 250C for UL listings.
MICA TAPES are UL listed at 450C but are capable of 538C continuous operating temperatures for commercial and industrial applications. Mica tapes are supported by a glass scrim backing that form the primary insulation. This composite tape is able to withstand severe electrical and thermal overload conditions. This high density mica paper permits tape designs with a minimum binder content (the weakest link thermally and in flame resistance) to electrically retain 60 to 70 percent of original dielectric strength after 1200 F to 1500 F exposure. It is highly resistant to radiation. Mica tapes are so highly insensitive to moisture that electrical integrity remains unchanged between one and 24 hour water immersion with over 50% retention of original dielectric strength. Mica has the best temperature resistance of all insulations, but needs a treated glass braid for mechanical strength.