Comparison of HDPE Geomembrane Production Processes
In terms of the HDPE geomembrane production process, there are currently two production methods in China, including internationally, which are blown film processes and flat extrusion processes. At present, 85% of the existing geomembrane production lines and most of the new geomembrane production lines in the world are blown film production lines. This is because compared to the extrusion process, the blown film process has the following advantages:
(1) For smooth HDPE geomembrane products:
The two different production processes have different requirements for high quality environmental geomembrane resin raw materials. The melt index of the resin material for the extrusion process is generally 0.11 g / 10min (test method ASTM D1238 Cond.E), and the melt index of the resin material for the blown film process is generally 1.0 g / 10min (test method ASTM D1238 Cond.E).
This is because the blown film process has higher requirements for resin raw materials and higher melting index requirements of the raw materials. The geomembrane products produced in this way also have better tensile ductility. From the aspect of actual construction on-site, HDPE geomembrane with better tensile elongation performance can better bear external load (landfill waste, heavy machinery, etc.). The specific test results are compared in the following table:
(2) For rough HDPE geomembrane products:
The blown film process is a one-step forming method. The rough surface of the geomembrane is formed by adding nitrogen blowing during production. The finished product is a whole. From the samples produced by the Canadian Soma blown film process, it is obvious that the rough spots of the rough surface are not easy to peel off. of;
The flat extrusion process is a two-step forming method. After the production of the smooth high quality aquaculture geomembrane is completed, the rough surface is formed on the smooth surface by spraying rough particles. The finished product is not an integral material, and the rough spots are easy to peel off, which greatly increases the possibility of landslide accidents.
Of course, whether it is a blown film or a flat extrusion process, the performance of the HDPE geomembrane is mainly based on the technical indicators of the geomembrane. For imported geomembrane, this index is the international index of GRI-GM13. In the international index, the geomembrane production process and the corresponding resin melting index are not distinguished and required. Under the same conditions, combined with the comparison of the above two production processes, considering the actual construction application level, most projects will still use the HDPE geomembrane material produced by the blown film process.