Thermally conductive electrical tape
AssigneeMinnesota Mining and Manufacturing Company
InventorRobert A. Brullo
Life of this patent
Estimating the term…
Abstract
Ethylene-propylene elastomer-based insulating (or semi-conductive) electrical tape is improved for long-term exposure to heat induced by high electrical current densities by the addition of sufficient thermally conductive non-black, non-reinforcing inorganic filler to endow the tape with a thermal resistivity no more than 350.degree. C.multidot.cm per watt.
Claims8
A thermally conductive tape capable of insulating heated conductor surfaces carrying high current densities, said tape being a strip formed of a composition comprising a blend comprised of ethylene propylene elastomer and an elastomer based principally on isobutylene, sufficient semi-reinforcing or non-reinforcing, non-black filler having a thermal conductivity of at least 1.1 .times. 10.sup.-3 cal.multidot.cm/cm.sup.2 .multidot..degree.C.multidot.sec to endow the tape with a thermal resistivity of no more than 350.degree. C.multidot.cm per watt, a modulus at 50% elongation of less than about 350 psi, and an ultimate elongation greater than about 700%, about 10-50 parts per 100 parts by weight elastomer of thermoplastic resin selected from polyethylene and polypropylene or mixtures thereof, about 5-75 parts per 100 parts by weight elastomer of compatible tackifier for said elastomer, and about 10-50 parts per 100 parts by weight elastomer of compatible plasticizers and softeners for said elastomers.
A thermally conductive tape capable of insulating heated conductor surfaces carrying high current densities, said tape being a strip formed of a composition comprising:
- a. about 100 parts of a blend comprised of 15 to 100 parts by weight ethylene propylene elastomer, with the balance being an elastomer based principally on isobutylene;
- b. sufficient semi-reinforcing or non-reinforcing, non-black filler having a thermal conductivity of at least 1.1 .times. 10.sup.-3 cal.multidot.cm/cm.sup.2 .multidot..degree.C.multidot.sec to endow said tape with a thermal resistivity of no more than 350.degree. C.multidot.cm per watt;
- c. about 10-50 parts (per 100 parts elastomer) by weight of thermoplastic resin selected from polyethylene and polypropylene or mixtures thereof;
- d. about 5-75 parts (per 100 parts elastomer) by weight of compatible tackifier for said elastomer;
- e. about 10-50 parts (per 100 parts elastomer) by weight of compatible plasticizers and softeners for said elastomer;
- f. up to about 15 parts (per 100 parts elastomer) curing agent for said elastomer;
- and
- g. up to 20 parts (per 100 parts elastomer) carbon black filler.
Dependencies are inferred from the claim text.