| abstract |
A process for producing an annular multilayer structure, comprising: providing, by stages of layer multiplication procedures, a multilayer flow stream of thermoplastic resinous materials, multilayer flow stream comprising a portion of microlayer having at least 30 layers and at least one additional layer on a first and a second side of the microlayer portion, a microlayer portion having a microlayer structure; supplying the multilayer flow stream to an individual distribution manifold (9, 10, 11) of an annular mold (100, 200); divide the multilayer flow stream into at least two flow streams, moving at least two flow streams in opposite directions around a circumference of the distribution manifold (9, 10, 11) forming an annular multilayer flow stream, overlapping one end of one of the flow streams one end of another flow stream in an overlapped zone, in which the multilayer structure is maintained in the overlapped zone; and eliminating the annular multilayer current from the annular mold (100, 200) to form the multilayer annular structure. |