Breitschlitzdüse zum Extrudieren eines thermoplastischen Kunststoffes

摘要

The slit die for extruding a thermoplastic consists of at least one manifold channel, a flow channel with a channel enlargement in which the plastics melt is decompressed and a pair of die lips between which the plastics melt is discharged from the slit die. Parallel to the walls of the channel enlargement, a multiplicity of flat-shaped heating elements are disposed on both sides of the flow channel, which heating elements are variable in their widths and are insulated with respect to the space deflecting towards the flow channel. The heating elements are at a distance D, from the walls of the channel enlargement, which is larger than 10 mm and is in particular 15 - 40 mm. The length L of the heating elements corresponds approximately to the length of the channel enlargement and is determined such that the average residence time of the plastics melt when flowing through this channel enlargement is higher than 3 sec. The individual heating elements are heated to the same or different temperatures.