Abstract: Disclosed is a process for producing a composite tubular member of two or more plastic materials. The product tubular member is leach and acid resistant and has inner and outer layers of thermoplastic material and an intermediate layer of a thermosetting resins. The process comprises the steps of: disposing a first layer of a thermoplastic material about a heated winding element for forming the inner layer, wherein the first layer is formed of polyvinylidene fluoride; fusing overlapping adjacent edges of the layer of polyvinylidene fluoride; disposing a second intermediate layer of a thermosetting resin about the inner layer of polyvinylidene fluoride; disposing a third outer layer of polypropylene about the second layer of the thermosetting resin; and fusing the outer layer of polypropylene to the intermediate and inner layers of the thermosetting resin and the polyvinylidene fluoride, respectively.