HDPE: Low-cost, functional polymer for injection moulding

FUNCTIONAL AND ECONOMICAL

HDPE, otherwise known as High Density Polyethylene, is this month’s material of the month.  Often regarded the “cheap and cheerful” thermoplastic polymer for plastic injection moulding, like all materials, it definitely has its place.

For one of our customers, IMI Webber, it was the ideal choice for their specialist, overmoulded, sintered filter.  Its excellent chemical resistance properties made it the best material choice for the automotive environment.  Part of a pneumatic manifold for a 4×4 suspension system, HDPE, in this case, is the perfect candidate and surpassed all other material options.

A thermoplastic polymer and member of the Polyethylene family, HDPE is produced from the monomer ethylene. With its high strength to density ratio and a specific gravity of 930-970 kg/m3 it has an excellent weight to strength ratio.

POPULAR POLYETHYLENE

Due to its strength, low cost and light weight, HDPE is also a popular material selection for: toys, food storage containers, drain-pipes, food preparation products, outdoor signage and household goods.

HDPE can be easily recycled too, with its own recycle code number (2).

If you’ve got an idea for a fabulous new product why don’t you get in touch with our product design and development team on 01425 613131 or email hello@becgroup.com, they’ll soon tell you if HDPE is the most product and cost appropriate material selection. But in the meantime, here’s a rundown of HDPE pros and cons:

Pros

· Low cost
· Tough
· Good chemical resistance (a lot of chemicals are supplied in HDPE containers)
· Recyclable
· Food grades available
· Can be heat welded (gas pipes)
· Doesn’t leach into food and water, containers etc
· Rigidity

Cons

· High thermal expansion
· Poor UV resistance (additives available)
· Subject to stress cracking
· Difficult to bond (glues)
· Flammable
· Can look cheap
· Poor temperature capability

Did you know?  HDPE is often the material selection for moulding containers, pallets, crates and packaging.