LDPE – CHEAP PLASTIC HAS ITS PLACE

Low-density polyethylene (LDPE) is our thermoplastic in the spotlight this month.

LDPE is a thermoplastic made from the monomer ethylene, the first grade of polyethylene, originally produced in 1933 by Imperial Chemical Industries (ICI).

As with all materials, the reasons why one material is selected for one product’s manufacture, can be a negative outcome for another.  For example: LDPE’s flexibility could be either a pro or a con, depending on how it’s finally intended for use.

LDPE has its own characteristics, if you push it, it moves, it’s fairly soft, has a good chemical resistance, is easy to mould and above all, it’s cheap. So, is often used for commodity mouldings.

Here at BEC, our design team carry out an incredibly thorough investigation at the start of every project. So, we go into the design for manufacture and material selection process, fully armed with information about how the end product or component is going to be used. How does it need to perform? Does it need to withstand any chemical, environmental or repetitive applications?

We can then propose the most suitable materials, so the end product meets its requirements.

Just like many others, LDPE sample swatches or mouldings can be supplied for evaluation and testing.  And because material selection is such a critical part of the process, we keep a comprehensive range of materials for trialling. With two mould shops on-site, sample mouldings can usually be carried out quickly, speeding up the verification process.

Pros

  • Economic – it is a cheap plastic
  • Low density
  • It floats! (Specific gravity of LDPE is 0.9-0.95)
  • Flexible with good impact resistance
  • Ductile – if you push it, it moves
  • Low working temperature range
  • Good chemical resistance
  • Commonly available
  • Easy to mould
  • Very easy to recycle and reuse, with its own recycling code #4.

Cons

  • Looks cheap
  • LDPE has poor UV resistance properties, (additives are available to improve it!)
  • Higher shrink rate can cause issues like distortion and shrinkage
  • Self-tapping screws can strip the material
  • Low mechanical strength
  • Comparatively low melting temperature
  • Soft … you wouldn’t use it for a coat hook!

Not many people know…

Squeezy bottles are usually made from LDPE, they are soft, food grade and cheap!

We injection mould products using a whole myriad of plastics, for customers across multiple industry sectors and for multiple applications.

With decades of plastic injection moulding experience, we can assist with your next material selection.

Give us a call on 01425 613131 or email hello@becgroup.com.