Patent ID: 6852188

Claim:
In a method for the manufacture of a thermoplastic fuel transport tube using thin film lamination, separate extrusion, tandem extrusion or coextrusion processes, wherein said thermoplastic fuel transport tube includes a thermoplastic form of a melt-processible tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer inner layer and a melt-processible polyamide outer layer, the improvement which comprises bonding said polyamide outer layer directly onto said tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer inner layer without the need for an intermediate tie layer to bond said melt-processible polyamide outer layer to said tetrafluoroethylene-hexafluoropropylene vinylidene terpolymer inner layer, wherein said bonding comprises the steps of: incorporating an adhesion promoter comprising an unsubstituted or substituted phenol salt of 1,8-diazabicyclo-[5,4,0]undec-7-ene on a novolac carrier into at least one of said polyamide outer layer and said tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer inner layer; and forming a multi-layer tubular member comprising said tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride inner layer and said polyamide outer layer in the absence of a separate intermediate tie layer between said tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer inner layer and said polyamide outer layer.