Patent ID: 6289958
Filing Date: 2001-09-18
Classification: B29D,B60C,Y10S

Abstract:
A pneumatic rubber tire composed of an electrically conductive carbon black reinforced rubber carcass, which contains two individual sidewalls, and two spaced apart bead portions, and which supports a peripheral, circumferential rubber tread of (a) a unitary rubber composition which has a high electrical resistivity, or of (b) a cap/base construction; wherein a rubber composition of said tread cap and/or said tread base has a high electrical resistivity; wherein the outer surface of the tread is designed to be ground-contacting, and wherein said high electrical resistivity of said rubber composition(s) is evidenced by the tire in the absence of the hereinafter provided stitched electrically conductive filamentary thread, having an electrical resistance of at least 20,000 mega-ohms according to Test WDK 110; wherein said tread has an electrically conductive filamentary, flexible, thread stitched through said tread to create an electrically conductive path from the outer surface of the tread to the electrically conductive tire carcass and to thereby form a tire having an electrical resistance in a range of about one ohm to about ten thousand mega-ohms according to Test WDK 110;wherein said tire is prepared by a process which comprises stitching an electrically conductive filamentary, flexible thread through an extruded, unvulcanized rubber tread strip; wherein said tread strip is of (a) a unitary rubber composition containing less than about 20 phr of carbon black reinforcement, or of (b) a cap/base construction wherein a rubber composition of said tread cap or said tread base contains less than about 20 phr of carbon black reinforcement; building said tread strip onto the carbon black reinforced rubber tire carcass to create an assembly thereof and vulcanizing said assembly in a suitable mold at an elevated temperature wherein the stitched thread defines stitchings, each stitching having a segment which extends over a portion of the inner surface of said tread strip.