Patent ID: 6967045

Claim:
A corrosion-resistant chemically continuous composite conduit having an inside and an outside, said conduit comprising from the outside to the inside: a) a first layer comprising a porous, mineral-containing substrate; b) a second layer comprising a thermosetting material, said thermosetting material containing a surfactant, a silane, and curing agent comprising isocyanate groups; c) a third layer comprising a thermoplastic material, said thermoplastic material impregnated with a reactive hydroxy-bearing resin; wherein an interface between said first and second layers comprises covalent bonds between said silane in said second layer and minerals in said first layer; wherein an interface between said second and third layers comprises covalent bonds between said isocyanate groups of said second layer and said reactive hydroxyl-bearing resin of said third layer; wherein said second layer is sufficiently rigid to transmit stresses between said first and third layers; wherein said third layer has a tensile strength sufficient to support a portion of said stresses; and wherein said first, second and third layers are bonded together with sufficient shear strength to transmit and distribute said stresses between said layers.