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Method of recovering crosslinked polyethylene with twin screw extruder

A twin-screw extruder, cross-linked polyethylene technology, applied in the field of recycling cross-linked polyethylene, can solve the problems of difficult recycling, low gel rate, high cost, achieve broad application and industrialization prospects, improve physical machinery performance, effect of increasing shear stress

Inactive Publication Date: 2004-08-18
SHANGHAI JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, cross-linked polyethylene is prone to waste during manufacture, and it is difficult to recycle due to its insoluble and infusible properties.
In order to recycle resources and avoid secondary pollution, the common method at present is to make cross-linked polyethylene pyrolyzed into low-molecular organic small molecules or fuel oil (Yingxing, Chemical Environmental Protection, 1998, 18: 215-219; Gerald Scott, PolymerDegradation and Stability, 2000, 68: 1-7; P.Onu, C.Vasile and et al., J.Analytical & Applied Pyralysis, 1999, 49: 145-153), but such process conditions are relatively harsh, and a high-temperature cracking device is required , and the small organic molecules or fuel oil produced are not single molecules, and the components are extremely complex, so they must be separated before they can be reused
Japan's Ichishi et al. (Open Patent Publication CA Ping 4-202444, 1990) use a counter-rotating twin-screw extruder to melt and mix to obtain a low gel ratio recycled PE material, but the equipment is complicated and requires a special double-screw extruder. screw
The above methods are quite difficult for general plastic processing plants, and the cost is high and uneconomical, so they have not been widely used.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0009] Embodiment 1: the preparation of particle diameter about 100 micron cross-linked polyethylene powder

[0010] Cut 90%wt strip-shaped cross-linked polyethylene into pellets, fully mix with 10%wt ultra-fine quartz powder under the high-speed mixer, the speed of the high-speed mixer is 1200 rpm, and put the mixed material into the twin-screw extruder Processing in the machine, the screw speed is 300 rpm, the temperature of the screw feeding zone, the plasticizing zone, and the mouth film are respectively 210°C, 220°C, 235°C, 245°C, 245°C, 245°C, 240°C and 230°C, The residence time of the material in the extruder is about 1.5 minutes. The extruded material is cooled in the cooling tank and placed in a centrifuge to remove moisture. The centrifuge rotates at 6000 rpm and dried in a cyclone dryer. The temperature of the machine is 80° C., and then it is pulverized in a high-speed pulverizer at a speed of 3000 rpm to obtain a cross-linked polyethylene powder of about 100 micro...

Embodiment 2

[0011] Embodiment 2: the preparation of particle diameter about 50 micron cross-linked polyethylene powder

[0012] Cut 85%wt strip-shaped cross-linked polyethylene into pellets, fully mix with 15%wt nano-molybdenum disulfide under a high-speed mixer, and the speed of the high-speed mixer is 1500 rpm, and put the mixed material into a twin-screw extruder Processing in the machine, the screw speed is 400 rpm, the temperature of the screw feeding zone, the plasticizing zone, and the mouth film are respectively 200°C, 215°C, 220°C, 225°C, 225°C, 230°C, 230°C and 225°C, The residence time of the material in the extruder is about 1 minute. The extruded material is cooled in the cooling tank and placed in a centrifuge to remove moisture. The centrifuge rotates at 6000 rpm and dried in a cyclone dryer. The temperature is 75° C., and then pulverized in a high-speed pulverizer at a speed of 5000 rpm to obtain a cross-linked polyethylene powder of about 50 microns.

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PUM

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Abstract

The present invention provides a method of recovering crosslinked polyethylene with twin screw extruder. Crosslinked polyethylene in 60-99.9 wt% and superfine inorganic material in 0.1-40 wt% are mixed in high speed mixer, the mixture is then produced into powder in a common twin screw extruder, and extruded material is cooled, dried and crushed in a high speed crusher to obtain crosslinked polyethylene power. The crosslinked polyethylene powder can be used as stuffing for mixing with other polymer to improve its physical and mechanical performance. The said method is simple and low in cost, and the present invention makes it possible for common plastic processing plant to recover crosslinked polyethylene.

Description

Technical field: [0001] The present invention relates to a method for recovering cross-linked polyethylene, in particular to a method for recovering cross-linked polyethylene with a twin-screw extruder. Physical and mechanical chain breaking is used to recover insoluble and insoluble cross-linked polyethylene. The screw extruder is equipped with a cooling and drying separation device and wear-resistant ultrafine inorganic powder is added to make the cross-linked polyethylene into a powder, which can be recycled. The invention belongs to the technical field of chemical polymer processing. Background technique: [0002] As we all know, compared with ordinary polyethylene, cross-linked polyethylene has excellent electrical insulation properties, higher impact strength and tensile strength, outstanding wear resistance, excellent stress crack resistance, creep resistance and size Stability, its heat resistance, low temperature resistance, aging resistance, chemical resistance, r...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B29C48/40B29B17/00
CPCB29C48/40
Inventor 戚嵘嵘周持兴
Owner SHANGHAI JIAOTONG UNIV