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Is Polyurethane a Plastic?

Polyurethane (PU) is a unique polymer that is elastic like a rubber but can be repeatedly stretched and reformed like a plastic. This tough, flexible and hard wearing material can be formulated using a wide range of starting materials to develop everything from paint to car parts, shoe soles and seals. So is Polyurethane a plastic? DLR Elastomer Engineering explains.

What is Polyurethane (PU)?

So what is Polyurethane and is it a plastic?

Polyurethanes (PU) are polymers (materials made of long, repeating chains of molecules) with a versatile chemistry that produce materials that behave like plastics and rubbers. PUs are made by reacting a polyol, which is an alcohol with more than two reactive hydroxyl groups per molecule, with a diisocyanate or a polymeric isocyanate in the presence of suitable catalysts and additives. The end result is a polymer boasting outstanding tensile strength combined with excellent tear and abrasion resistance.

It is the wide range of starting materials that can be used that ensures PUs exhibit both plastic and rubber characteristics. There are PUs that are rubbery and elastic, which can be melted and formed into parts and the cycle repeated! This means that Polyurethane products can be developed using cost-effective, sustainable Polyurethane casting and moulding techniques. Both of which are desirable outcomes for the modern manufacturer.

PUs come in a wide range of hardnesses using just two or three chemicals combined in a smart way. These materials are tough, flexible and hard wearing. Parts manufactured using a PU can be coloured and finished off to high gloss levels. They can also be manufactured to include inserts, such as metal fixings, other polymers, or PUs of different hardnesses. The advantages of Polyurethane don’t stop there either.

Advantages of Polyurethane

Thanks in no small part to their high degree of durability and excellent resistance to oxidation, ozone and petroleum-based fuels and oils, PUs are extremely versatile materials. The fact that they can be formulated to be either rigid or flexible makes them suitable for a wide range of applications. For instance, Polyurethane is a particularly good choice for custom moulded products intended for oil and gas applications.

Polyurethane also exhibits good electrical properties, which makes it especially useful as a coating to protect electrical products. It is commonly used to insulate buildings and white goods, such as refrigerators and freezers. In fact, a 1.6cm thick Polyurethane sheet of insulation delivers the same insulation as a 1.34m thick concrete wall! As PUs are typically liquid cast, tooling prices also tend to be lower than for heat and pressure moulded elastomers.

Applications of Polyurethane

Cast PU is used in a vast array of applications, including the following:

  • Abrasion-resistant coatings
  • Moulded diaphragms
  • Gaskets
  • Haul-off pads
  • Hoses
  • Seals

Contact DLR Elastomer Engineering today

The performance of polymers comes from their molecular make-up and, more importantly, their molecular weight. Whether you’re looking for a tough and flexible part or a part that is stiff and impact-resistant, our knowledge and expertise here at DLR Elastomer Engineering means that we can tailor the chemistry to your specific needs. We will support your business with the development of high-quality cast PU parts that are tailor-made to suit your application.

If you have a technical question, or would like further product information including a detailed quote, contact DLR Elastomer Engineering today at technical@elastomer.co.uk. Our team will be happy to help in any way we can.

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DLR Elastomer is a leading manufacturer of bespoke elastomeric products & components for high performance industrial & engineering applications.