| 摘要 |
<p>Method comprises subdividing the original polymer streams from the separate extruders or pumps, into a number of part streams which is larger than the desired number of layers in the end product. At the same time, these part streams are brought into the desired sequence, and when brought together in one or more groups, they are spread out groupwise. The device used divides at least two polymers into a series following a selected sequence of streams one above the other, and simultaneously these streams are spread out to the desired width of the end product. It consists of a central block in which a number of chambers, greater in number than the layers in the end product, open at least on the front side of the block. There is at least one lateral connection for one or more extruders, and at least one port plate with at least one distributing channel for delivering synthetic material from the extruders to one or more chambers in the block. Method avoids asymmetry of the layers in the spreading phase, without a large number of connections needing adjustment. The technique is of especial value when the end product has large ratios of layer thicknesses (e.g. 1:3) and/or when the viscosity and/or the extrusion temperature differs considerably between the polymers.</p> |
