What is the difference between rubber and polyurethane?
Wheels are made from rubber or polyurethane, so polyurethane (PU) wheels are made from polyurethane and rubber wheels are made from rubber.
Rubbers and Polyurethanes are commonly used in the manufacturing of wear components for a variety of industries including agriculture, transportation, recycling waste management and offshore.
Rubber and Polyurethane is ideal for these types of components as they can be moulded into a seemingly endless variety of designs suitable for all manner of processes.
We will now explore the differences between the two materials and discuss some of their advantages and disadvantages.
Rubber is an elastomer, which put simply means it is a material that has elastic properties. Historically natural rubber, which is latex based and harvested from Rubber Trees (Hevea Brasiliensis) was a prime source for rubber products.
The first synthetic rubber that could be used as a replacement for natural rubber was developed at I.G. Farben in Germany in 1929. This synthetic rubber material was known as Buna S to the Germans and became known as SBR (styrene-butadiene rubber) in Britain.
Nowadays, having several rubber compounds we can chose from: each with different hardness ranges, temperature, oil, chemical and ozone resistances. These compounds include the original natural rubber and the synthetic SBR material as well as EPDM, Neoprene, Hypalon, Silicone and Viton among others.
Rubber can be compression moulded and transfer moulded for the production of components or hand fabricated for the production of items such as lined drums or covered rollers.
Rubber is used in some of the most common everyday items including tyres, seals, and gaskets on your car as well as a multitude of components in industrial and commercial machinery. Rubbers natural grip, flexibility and elasticity make it a prime material for so many processes and parts.
Polyurethanes are a polymer; they come in a variety of types and are also known as elastomers. Polyurethane is a chemical based material and was developed by Friedrich Bayer (founder of Bayer pharmaceuticals) in Germany in 1937. World War II sped up the development of elastic polyurethanes as a replacement for natural and synthetic rubber materials.
What makes polyurethane a great material is that is has the elastic properties of rubber but with the rigidity of a plastic and because it is a chemical based compound, with the use of additives and dyes the variation of colours available is huge.
Polyurethane can be used on many of the same applications as rubber, such as wear components on industrial machinery and protective coverings but can also be adapted and used in such things as insulation products, paint, and furniture padding, wheels.
Polyurethane is easily processed and can be moulded via open or closed cast moulds and injection moulding. You can even purchase home moulding kits and create small, simple components at home.
Rubber and Polyurethane are as different as they are similar:
Both rubber and polyurethane have elastic qualities, are mouldable and flexible.
Rubber materials generally offer better grip qualities whereas polyurethanes are generally seen as more durable.
Polyurethane components can be manufactured in a wide variety of colours whereas the colour variation with rubber compounds is more limited.
Choosing between these two material types can be difficult. Sometimes cost, manufacturing time or the end components purpose can be the deciding factor.