| 摘要 |
<p>A die head (16) for forming multiple tubular plastic parisons having a plurality of barrier walls contained in a matrix resin so as to form a plurality of discontinuous, substantially two dimensional barrier walls within the matrix resin which overlap one another so as to form a barrier to permeability. The die head (16) includes a diverter sleeve (42) for each parison to create two counter-rotating circumferential spiral flow channels (48, 50) of resin to form each parison wherein the barrier resin within the matrix resin is stretched to form streaks which are then elongated to form platelets within the matrix resin. The two spiral flow channels (48, 50) form parisons having two concentric layers, each layer having a radial weld line. By positioning the weld lines in each layer circumferentially offset from each other, a single radial weld line through the parison is prevented. The spiral flow channel also increase the impact strength of the container and improves the uniformity in the parison wall thickness. <IMAGE></p> |
