High and Low Density Polyethylene (Polyolefin’s)
High Density Polyethylene (HDPE), is used for film applications, blow moulding applications, pipe, injection moulding applications, tapes, monofilaments and fibres.
Low Density Polyethylene (LDPE), is highly flexible and used in packaging film, waste and grocery bags, agricultural mulch, wire and cable insulation, squeeze bottles, toys and house wares.
Comparison
Compared to LDPE, HDPE has greater rigidity, hardness, heat distortion temperature (HDT) and chemical resistance but lower impact strength. It has better low temperature properties than polypropylene homopolymer but is not as flexible or as hard. As with polypropylene the material is resistant to boiling water.
UV Resistance
HDPE is translucent white in its natural condition and is therefore easy to colour. UV stability is satisfactory although if the material is to have long term exposure then UV stabilisers will need to be used for added protection.
As these materials have a waxy surface, they not suited to joining by using adhesives. Therefore, other methods of joining, such as snap-fits or welding, need to be considered. Machining can be difficult but is possible.
Low Density Polyethylene and High Density Polyethylene can easily be processed by Injection Moulding, and ProPlastix can advise on your specific applications.
