Multi-layer coextruding die head of extruder

Abstract

The invention discloses a multi-layer coextruding die head of an extruder. The multi-layer coextruding die head comprises a die body, a die core and a plurality of material inlet pipe openings. An air inlet channel is formed by the axis of the die core. A compound coextruding channel is arranged in the material outlet outer end between the die body and the die core. A plurality of layers of material inlet channels are formed by helical sleeves in the material inlet inner end. The material inlet pipe openings are communicated with the compound coextruding channel by the plurality of layers of material inlet channels. The die core is provided with a cooling sleeve. Independent helical air channels that twist and turn along the axial direction and are arranged on the wall part at two sides of the cooling sleeve and axle centers forms a part of the air inlet channel. The outer end part of the cooling sleeve is provided with channels that are communicated with two helical air channels. The inner end of the die body is provided with an air inlet pipe and an air outlet pipe of an external cooling circulating system. The air inlet pipe and the air outlet pipe are communicated with the inner ends of the two helical air channels. A multi-layer coextruding die head of the extruder capable of adjusting the internal temperature of the die head is provided by the invention.

Description

technical field [0001] The invention relates to a multi-layer pipe material extruder, in particular to a multi-layer co-extrusion die head of the extruder. Background technique [0002] PE-RT pipe is a new type of plastic pipe developed and applied in the early 1990s. Some people call it the fifth-generation new type of pipe. It is mainly used in building hot water systems, drinking water systems and floor heating systems. When the internal pressure is 1Mpa, the service life can reach 50 years. PEX pipes are being phased out in China. PE-RT has become a good substitute product due to its non-toxic and hygienic properties, heat-resistant heat preservation, simple and reliable connection and installation, wear resistance, anti-freeze cracking, and waste recycling. [0003] At present, most pipes are oxygen-resistant PERT pipes with a three-layer structure, that is, a layer of hot melt adhesive and EVOH resin layer is evenly coated on the outside of the PERT pipe. The structur...

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Problems solved by technology

[0003] At present, most pipes are oxygen-resistant PERT pipes with a three-layer structure, that is, a layer of hot melt adhesive and EVOH resin layer is evenly coated on the outside of the PERT pipe. The structure from outside to inside is EVOH oxygen barrier layer / hot melt adhesive / PERT , because EVOH resin is easy to absorb moisture and its oxygen barrier ability will be greatly reduced after moisture absorption. At the same time, it is easy to scratch the surface of the pipe during construction and reduce the oxygen barrier of the pipe.

Therefore, this three-layer PERT tube cannot be called a "true oxygen barrier tube"

Furthermore, a five-layer co-extruded oxygen barrier PERT pipe was introduced, and its structure from outside to inside is PERT / thermosol / EVOH oxygen barrier layer / thermosol / PERT. It is not difficult to see from the layer structure that the oxygen barrier of the five-layer PERT pipe The performance is relatively ideal, but at present, most of the co-extrusion machine dies that manufacture this five-layer PERT pipe do not have corresponding devices to prevent the internal temperature of the die from being too high. When the internal temperature of the die is too high, it will affect the smoothness of the inner wall of the pipe product. Thus affecting the quality of pipe products, causing some unnecessary losses

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