There are 3 plastics for twin wall profile extrusion.
Polypropylene(abbr: PP)
PP is tough, flexible, and solvent-resistant. Those features allow PP to be used as packaging plastic, we use them as the main resin. Normally, people use twin-wall PP sheets for making signboards, protection sheets, and packaging boxes
High-Density Polyethylene(abbr: HDPE)
HDPE is known for its large strength-to-density ratio, compared to polypropylene, it is more rigid and more transparent and can withstand long-time exposure to sunlight. We normally use them to make tree shelters and vine guards which can endure both low & high temperatures, in the meantime can promote plant growth due to their higher light transmittance
Low-Density Polyethylene(abbr: LDPE)
LDPE is chemical resistant and very flexible, we often use them for making buffer material and thermal insulation material, such as plastic covers for greenhouses and bucket coats. Because of its low density and low flow rate, productivity for twin wall LDPE extrusion is not high, this is also reflected in the final production cost.
Of the 3 plastics, we mostly use PP as the raw material for the twin wall profile extrusion.