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Hollow, multi-layered plastic structures are provided comprising a layer of thermoplastic polyester material and a layer of polyethylene, the polyethylene and polyester layers being cross-linked together at their interface. A process for producing such structures which comprises charging a mold with

Hollow, multi-layered plastic structures are provided comprising a layer of thermoplastic polyester material and a layer of polyethylene, the polyethylene and polyester layers being cross-linked together at their interface. A process for producing such structures which comprises charging a mold with thermoplastic polyester material, rotating and heating the mold so as to fuse and form a layer of the polyester material on the inner surface of the mold, cooling the mold to a point below the melting point of the polyester but above the melting point of a subsequently added cross-linkable polyethylene material, stopping the rotation and charging the mold with the cross-linkable polyethylene material, resuming the rotation of the mold and heating it to a temperature sufficient to fuse and cross-link the polyethylene with the polyester layer, cooling the mold to a point below the melting point of the polyethylene and removing the finished structure from the mold.

대표청구항 ▼

A process for producing a hollow, multi-layered cross-linked, plastic structure from a linear thermoplastic polyester and a cross-linkable polyethylene having a melting point lower than the melting point of the polyester, said process comprising the steps of: charging a mold with a sufficient amount

A process for producing a hollow, multi-layered cross-linked, plastic structure from a linear thermoplastic polyester and a cross-linkable polyethylene having a melting point lower than the melting point of the polyester, said process comprising the steps of: charging a mold with a sufficient amount of the thermoplastic polyester material to form a substantially uniform layer on the inner surface of said mold; heating said mold to a temperature above the melting point of the polyester; rotating said mold so as to fuse the polyester contained within the mold and to uniformly distribute the fused polyester on the inner surface of the mold; cooling said mold to a temperature below the melting point of the polyester but above that of the cross-linkable polyethylene thus crystallizing the polyester to a solid layer; stopping the rotation of the mold; charging said mold with a sufficient amount of the cross-linkable polyethylene to form a substantially uniform layer on said polyester layer; heating said mold to a temperature above the melting point of the polyethylene and sufficiently below the melting point of the polyester so as not to cause dimensional distortion of the polyester; rotating the polyethylene charged mold for a sufficient period of time to fuse said polyethylene, uniformly distribute the polyethylene on the inner surface of the polyester layer and effect cross-linking of said polyethylene so as to set the polyethylene layer and effect cross-linking of said polyethylene to said linear polyester; and stopping the rotation of said mold to remove the resulting hollow, cross-linked multi-layered polymeric structure.