Coextruded polyester splicing tape

Claim 1

A splice comprising sheet ends abutted to define a juncture line, a layer of thermoset adhesive overlapping said juncture line and adherently bonded adjacent said juncture line to the surface of said sheet ends, and adherently bonded to the surface of said layer of thermoset adhesive a biaxially oriented and heat-set coextruded film consisting essentially of (A) a base layer of dimensionally stable crystalline first polyester selected from the group consisting of polyethylene terephthalate, polycyclohexane dimethyl terephthalate and polyethylene naphthalate (B) an adhesion-promoting layer having a thickness from about one-fourth of the total thickness of said support layer to about 1 mil thick of a second polyester having a minor degree of crystallinity between about 20° C and 230° C and melting at a temperature less than about 230° C wherein said adhesion-promoting layer is a polyester produced by the condensation reaction of a dicarboxylic acid component consisting of from about 10 to about 100 mole percent of a dicarboxylic acid selected from the group consisting of isophthalic acid, hexahydroterephthalic acid, sebaic acid, succinic acid, adipic acid, azelaic acid, suberic acid, pimelic acid, glutaric acid or mixtures thereof, or the diesters of such acids and correspondingly from 90 to zero mole percent of terephthalic acid, and a glycol component, in substantially equimolar proportions with the dicarboxylic acid component, wherein the glycol component is selected from the group consisting of polymethylene glycol of the formula HO(CH 2 ) n OH, wherein n is an integer of 2-10, neopentyl glycol, 1,4-cyclohexane dimethanol and bisphenol A, said coextruded film being bonded to said thermoset layer on said adhesion-promoting layer surface.