Contact usPolypropylene, as copolymer or homopolymer, is commonly used for mechanical components in corrosive environments. It is challenging to machine due to low annealing temperature. This guide covers attributes, applications, finishing, and stock sizes.
Polypropylene (PP) also known as polypropene is a hydrocarbon polymer and is one of the most commonly produced plastics in the world.
It is sometimes referred to as the ‘steel of the plastic industry’ due to its adaptability.
PP is a thermoplastic that is available as a Copolymer and Homopolymer. It is commonly used for mechanical components in corrosive environments.
Polypropylene has gained a reputation for being tricky to machine due to its low annealing temperature. It therefore requires a high level of skill.
As well as a sharp cutting edge and slow feed rates, we use plenty of coolant to aid lubrication, remove swarf and help keep the PP below its melting point.
Penta Precision has decades of polypropylene machining experience so you are in safe hands.
You may also see Polypropylene referred to as:
Polyethylene is available as a Homopolymer (PPH) and Copolymer (PPC). Material selection may depend on application and desired properties although the attributes are very similar and they are largely interchangable materials. Here is a brief overview of each.
PPH is the more widely used general-purpose grade of Polypropylene. It has improved chemical resistance and stiffness and also has a higher working temperature than the PPC variation (0-100°C). It is slightly more expensive than PPC although still relatively inexpensive.
Although PPC has a relatively lower chemical resistance than PPH, it is still considered to be very good. Its operating temperature range is not as high (up to 80°C) but it has improved impact strength at lower temperatures (down to -20°C).
It also has lower susceptibility to stress cracking. Whilst both are suitable for use with food, the copolymer is more commonly selected for food-related applications. PPC is more transparent than PPH and generally used where more flexibility is required.
PPC can be further divided into random and block copolymers, produced by the polymerizing of propene and ethane.
Random copolymers features up to 6% Ethene which is randomly dispersed. They are flexible and optically clear.
Block copolymers feature between 5 and 15% ethane and the co-monomer units are arranged in a regular pattern, making it tougher and less brittle.
Polypropylene has poor bonding properties and is therefore difficult to paint so we do not advise it.
See our Finishing Processes page for further information on services that we can facilitate.
Here are the standard stock sizes/colours for Polypropylene in the UK. Please note we do not supply stock material, the information provided is purely for design and research purposes.
Stock sizes vary by supplier. The following sizes are for TECAFINE PP and TECAPRO MT.
The properties of Polypropylene will depend on the type. The below information is for TECAFINE which is a brand of Homopolymer PP.
