Long Glass Fiber Reinforced High-Density Polyethylene (HDPE-LGF) is a high-performance thermoplastic composite made by reinforcing HDPE resin with long glass fibers using a continuous fiber impregnation process. Compared to short glass fiber filled HDPE, this material offers significantly enhanced mechanical properties, fatigue resistance, creep resistance, and structural stability, while retaining HDPE’s excellent chemical resistance and processability.