A thermoplastic tube for transfer of hydrocarbon fuel comprising an inner
fluoroplastic layer and an outer polyamide layer bonded to the
fluoroplastic layer wherein an adhesion promoter is included in at least
one of the layers is disclosed. The adhesion promoter is an unsubstituted
or substituted phenol salt of 1,8-diazabicyclo-[5,4,0]undec-7-ene on a
novolac carrier which functions to increase the adhesive bond strength
between the two layers. The adhesion promoter provides a chemically bonded
adhesion in addition to the mechanical adhesion associated with extrusion
or lamination of the layers.
