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Elongation Strippable Insulation

IP.com Disclosure Number: IPCOM000078991D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Nollner, KR: AUTHOR [+3]

Abstract

Readily strippable insulated wire can be provided by utilizing an insulation coating which can be fractured by elongation, and has the property of being readily released from the wire. If the yield strength of the insulation is considerably less than that of the wire, the insulation fracturing and stripping can be carried out by stretching the insulated wire.

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Elongation Strippable Insulation

Readily strippable insulated wire can be provided by utilizing an insulation coating which can be fractured by elongation, and has the property of being readily released from the wire. If the yield strength of the insulation is considerably less than that of the wire, the insulation fracturing and stripping can be carried out by stretching the insulated wire.

Wire 10, typically of annealed copper or copper alloys capable of 25% elongation without fracture, is coated by a two layer insulator system 12, 14. Layers 12 and 14 may be formed of "PYRE-M.*," a polyimide insulator material.

Layer 12, in the range of 150 millionths of an inch thick, is overcured at approximately 800 degrees F to provide a film which adheres less tenaciously to the copper, and has greater brittleness than would be the case had it not been overcured. Layer 14, also 150 millionths of an inch thick, is cured at 600 degrees F to provide good adhesion to layer 12 and a high degree of flexibility. Combination 12, 14 provides a balance that will, if elongated beyond a designed point, rupture in an annular fashion. The insulator system ruptures first at 16 in the overcured layer 12, and this stress propagates to rupture elastic layer 14 around an annular section 18 overlying the first rupture line 16. Wire 10 will neck down slightly in the elongation zone 20, and the initial diameter of 10 should be chosen to allow for this.

In practice the wire is gripped mechanica...