Abstract: The pipe is intended for carrying a petroleum effluent comprising at least one of the acid compounds CO2 and H2S. The pipe comprises at least one metal element (3, 5) and a tubular sheath made of a polymer material (2, 4), the metal element being provided outside the sheath. The sheath consists of a mixture of a polymer material with a predetermined amount of products chemically active with said acid compounds so as to irreversibly neutralize the corrosive effects of said compounds and to limit the corrosive effects on said metal elements. The pipe is characterized in that the chemically active products are incorporated into the sheath in form of particles of specific surface area above 5 m2/g.

Abstract: The present invention relates to a composition comprising a mixture of polymer material (4) and of mineral fillers (5) allowing to obtain a sealing barrier to hydrocarbons. The mixture comprises a predetermined proportion of specific mineral fillers for adsorption of all or part of the hydrocarbons that pass through the material by permeability. The proportion is determined depending on the permeability of the polymer material. The invention also relates to its applications to hydrocarbon tanks (gasoline, diesel oil, solvents) for example for motor vehicles, or hydrocarbon-carrying lines.

Abstract: The present invention relates to a multilayer structure with controlled permeability to hydrocarbons, comprising at least one inner polymer layer (6) and at least one outer layer (5) comprising a mixture of polymer material and of fillers. The fillers are mineral and selected to adsorb and to trap an amount of hydrocarbons released through said inner layer so as to reduce the permeability of the structure. Application to the manufacture of fuel tanks or lines.

Abstract: Fibre-reinforced tubes made of a thermoplastics material are manufactured using a method of extruding thermoplastics material in a drawplate with a diverging end zone, the end zone of which has a diverging annular flow space which has a ratio A.sub.s /A.sub.e between the exit area and entry area of at least 1.2, and a ratio between the length 1 of the lower edge of the annular exit space of the diverging zone and the width e of the straight section of said annular space which is less than 5; the extrusion operation being carried out in the presence of a liquid lubricant which is incompatible with said thermoplastics material at extrusion temperatures, said lubricant being present at the level of the external wall and at the level of the internal wall of said flow space. Tubes which are manufactured by way of this method are particularly resistant to a high degree of bursting and have an improved surface quality.