Geomembrane Production: How Blown Film Technology Effectively Provides Seepage Control

Geomembranes are a critical anti-seepage material in infrastructure projects such as water conservancy projects, landfills, and tailings ponds. Among various production processes, blown film has become the mainstream process for producing high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) geomembranes due to its excellent ductility and stable anti-seepage performance.

Step 1: Raw Material Selection - The Foundation of Quality

The production process begins with rigorous raw material inspection. Bemax geomembranes utilize 100% virgin polyethylene resin (such as Marlex HDPE). These resins undergo three key tests: infrared spectroscopy (to verify molecular structure), moisture content analysis, and visual inspection for discoloration or agglomeration. Only flawless raw materials proceed to the next step.

Step 2: Extrusion and Film Blowing - Membrane Formation

Qualified resin is fed into the extruder. At temperatures between 200°C and 230°C, the resin melts into a viscous polyethylene fluid. The fluid is then pushed through a circular die, forming a continuous "tubular film bubble," hence the name "blown film." A pulling device pulls the film bubble upward while simultaneously injecting compressed air to expand it. The expansion ratio (for example, a 6-meter-wide geomembrane has a ratio of 1:3) determines the product's width and thickness, and a laser thickness gauge ensures a tolerance of less than ±10%.

Step 3: Cooling, Finishing, and Quality Inspection

The hot film bubble (over 180°C) is rapidly cooled to below 50°C by cooling rings and circulating water at 30°C to prevent wrinkling or brittleness. The cooled bubble is flattened into a double-layer film and then cut into rolls.

Why Choose Blown Film Geomembrane?

According to the China Geosynthetics Engineering Association, over 70% of geomembranes produced in China are produced using the blown film process. Blown film geomembranes have a dense molecular structure (with a permeability as low as 1×10⁻¹³cm/s), excellent tensile strength, and resistance to acid and alkali corrosion, making them suitable for complex engineering environments. Huaxiang New Materials plans to incorporate AI control into its film blowing process, fully automating raw material mixing, temperature regulation, and thickness monitoring, further improving quality consistency.

Bemax's film blowing technology continues to upgrade, strengthening the "first line of defense" for infrastructure security.