HDPE, PE-HD

High-density polyethylene (PE-HD, HDPE) belongs to soft and flexible thermoplastics.

Production:

• medium pressure method (Philips method), in which the pressure is 30-40 bar, temperature 85-180°C and the catalyst is chromium oxide
• low-pressure method (Ziegler method), where the pressure is 1-50 bar, temp. 20-150°C and the catalysts are halotitates, titanium esters and aluminum alkyls
• Polymerization is carried out in suspension, solution, gas phase or in bulk.

Properties:
The density of HDPE is from 0.942 to 0.965 g/cm3. Contraction: 1.5-3%. The degree of crystallinity is from 60 to 80%. The melting point of HDPE is from 126 to 135°C. High density polyethylene is lighter than water, it can be formed, machined and welded. Polyethylene is resistant to water, salt solution, acids, alkalis, alcohols and gasoline. HDPE is not resistant to strong oxidizing substances, such as sulfuric acid, nitric acid or some cleaning agents. It is odorless, tasteless and physiologically neutral.

Processing:
In injection molding, the HDPE mass temperature is from 160 to 260°C, and mold temperature from 30 to 70°C. In blow molding, the temperature of the alloy and mold ranges from 160 to 190°C. The HDPE extrusion method is processed in the temperature range from 160 to 390°C.

Application:
High density polyethylene (HDPE) is used, among others, for the production of fuel oil containers, fuel canisters and fuel tanks for cars, garbage tanks, pressure pipes, couplings, tap water and wastewater fittings, plates, equipment for the chemical and automotive industry, bottle crates and barrels.