The impermeable membrane is formed using the principles of blow molding or extrusion calendering. The raw material used for production is HDPE resin, which can be either granular or powdered. In addition to using basic HDPE raw materials in the production process, auxiliary agents are usually added in proportion to improve the HDPE membrane's wear resistance, aging resistance, and UV resistance. For example, antioxidants and light stabilizers may be added. Ethylene can also be copolymerized and modified with a small amount of 1-butene or propylene. The most common type of impermeable membrane produced by blow molding is a smooth-surfaced membrane. If the blow molding system consists of several extruders and the mold is designed in multiple layers, blow molding can also produce composite impermeable membranes (also called composite geomembranes) and textured impermeable membranes.
Since HDPE membranes are made from HDPE resin, they inherit all the properties of HDPE. These include excellent waterproof, corrosion-resistant, and moisture-proof capabilities, strong resistance to UV rays and intense sunlight, and excellent resistance to extreme cold. Therefore, even in northeastern regions where outdoor temperatures can drop to -50℃, HDPE membranes still maintain good waterproof, corrosion-resistant, and moisture-proof performance. They are chemically stable, highly resistant to decomposition, have good mechanical strength, and are environmentally friendly, non-toxic, and odorless.
