cheap hdpe panel 4×8 20mm st-HDPE 4×8 polyethylene sheet HDPE. Density. 0.96-1 g/cm3. Shore Hardness. 55-70 A. We offer quality assured range of HDPE sheets, also known as High Density Polyethylene Sheets. It has high-density polyethylene, unlike polypropylene and cannot withstand normally-required autoclaving nditions.