Thermoplastics: which to choose for your product?

11 December 2018

Did you know that there are thousands of types of thermoplastics? New plastics are constantly being developed. How can you choose the best material to use for your injection-moulded product? To help you with this choice, we will go over the properties and applications of a number of commonly used thermoplastics with one of our resident plastics experts, Fred Bijsterveld.

Polypropylene (PP)

Also known as “polypropene.” “poly” means “many,” while “propylene” means “a particle of propene.” Polypropylene therefore contains many particles of propene. This plastic is suitable for a wide range of applications. For example, Rompa Group uses it to manufacture components for Britax Römer car seats and cartridges for Philips. It is important that these seats are sturdy and can never break, but they must also allow for a degree of flexibility (impact resistance). PP offers the right combination of stiffness, elasticity and impact resistance.

   Product made from PP

Product made from PE

Polyethylene (PE)

Polyethylene, with its long molecular chain – which can be made even longer with relative ease – is used to produce extremely durable and sustainable products. Because of its structure, this type of plastic is stronger, tougher and more viscous and offers a higher degree of chemical resistance. PE is therefore commonly used to produce gas pipelines and packaging materials for chemical substances.

Acrylonitrile-butadiene-styrene (ABS)

This type of plastic can be given a glossy finish. ABS is often used to produce consumer products for the home, e.g. data carriers, routers and TV tuners. The material offers a high degree of stiffness and scratch resistance.

                   Wireless charging pad

                 PA in a car

Polyamide (PA)

This material is known for its resistance strength. Polyamides can be either filled or unfilled. With filled polyamides, a certain percentage of the material consists of glass particles, which improves its strength. This makes filled polyamides exceptionally useful for technical applications that need to be strong, flexible and resistant to wear. Unfilled polyamides do not feature these glass particles.

High-performance plastics (HPP)

The category of high-performance plastics includes materials that possess several extreme properties. For example, polysulfone (PSU) and polyetherimide (PEI) offer tremendous resistance to pressure and high temperatures. These plastics are therefore used in e.g. the housing of coffee makers, where coffee beans are ground up under high pressure. Another example of an HPP is polyetheretherketone (PEEK), which is used for applications with electrical conductivity.

              Product from PSU

A complete range of thermoplastics

Rompa offers the full range of thermoplastics. “Each type of material behaves in its own unique manner,” project manager Fred Bijsterveld emphasises. “The degree of shrinkage, how fast the material can be taken out of the mould, its flow properties and the rate of crystallisation are just a few of the variables in play. During the DFM process, we evaluate the manufacturability of the product. We also select and (if needed) advise about the most suitable type of plastic to use.” In some cases, Rompa tests various materials together with the client. 

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New plastics

Fred: “New materials are constantly being developed. For example, the relatively new combination PET-PBT is extremely popular in the automotive industry. The best properties of both materials have been rolled into one. The result is a strong material with optimal mechanical properties. It is perfect for the production of the plastic components of windshield wipers that have to last a long time under harsh conditions and are absolutely not allowed to snap off, because that could be extremely dangerous.”