Extrusion mixing device in PP foam sheet extruder

Abstract

The invention discloses an extrusion mixing device in a PP foam sheet extruder, and the extrusion mixing device can realize precise temperature control and even material mixing. The extrusion mixing device includes a cylinder in the shell, the feed end of the cylinder is communicated with a feed pipe, the discharge end of the cylinder is in seal communication with a discharge port equipped discharge casing pipe, the inside of the cylinder wall's sleeve gasket layer is surrounded by several sections of cooling water pipes, the water inlets of the cooling water pipes are all communicated with a water inlet pipe, the cylinder's outer wall corresponding to each section of cooling water pipe is sleeved with a section of heating ring. In the cylinder, one end of the extrusion screw extends into the discharge casing pipe, and the other end of the extrusion screw is in mutual seal with the cylinder inner wall and is driven to rotate by a driving unit. The extrusion screw is equipped with at least two sections of multi-start screw threads, a guide channel is formed between adjacent two-start screw threads in each section of multi-start screw thread, and the longitudinally adjacent guide channels are mutually staggered.

Description

technical field [0001] The invention relates to the technical field of PP foam board production, in particular to a mixing device in a PP foam board extruder using liquid carbon dioxide as a foaming agent. Background technique [0002] PP foam board is polypropylene foam board. PP foam board is widely used in auto parts due to its excellent mechanical properties, remarkable heat insulation effect, good resilience and corrosion resistance, and recyclable regeneration. , equipment manufacturing, stationery, packaging, building materials and other fields. Foaming agent is one of the important raw materials in the production of PP foam board, and the traditional foaming agent is Freon. Since Freon will cause extremely serious damage to the ozone layer, liquid carbon dioxide is increasingly used as a blowing agent instead of Freon in the production of PP foam boards. [0003] The most critical step in the production of PP foam boards using liquid carbon dioxide as a foaming age...

AI Technical Summary

Problems solved by technology

However, at present, the mixing device of PP foam board used in the production of PP foam board with liquid carbon dioxide as foaming agent has poor uniformity of liquid carbon dioxide mixed with PP melt, and the mixing shear during the mixing process The force makes the temperature of liquid carbon dioxide and PP molten material rise continuously, and it is difficult to accurately control the temperature of the mixed material at the required 140 ° C, which greatly reduces the performance and quality of PP foamed sheet

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