BigPatents India

A process for making a composite vessel includes the steps of: A) preforming a composite shell (63) for the vessel (for example, by winding fiberglass and a thermoplastic material onto a thermoplastic mandrel) which includes a thermoplastic film liner (66) sealing the interior surface thereof; B) in a mold (60) (which optionally may be heated), heating the composite shell and thermoplastic film liner while applying at least one force (9) (by, for example, evacuating the mold, pressurizing the thermoplastic film liner or both) which tends to urge the thermoplastic film liner and the composite shell outwardly; C) continuing step B) until the thermoplastic film liner and the composite shell consolidate and the exterior surface of the composite shell becomes fluid and flows to conform to the interior surface of the mold, thereby forming the composite vessel; D) allowing the formed composite vessel to cool; and E) removing the formed composite vessel from the mold. Suitable thermoplastic materials includes: polyethylene, polypropylene, polybutylene terephthalate and polyethylene terephthalate. The resulting composite vessel exhibits superior mechanical and aesthetic properties.