Back in the early days of the development and use of casters – 100 years ago or more – there were few choices for wheel materials. If you wanted hard wheels, you used metal. If you needed soft wheels, natural rubber was the main option. And if you wanted something in between, wood was a popular choice.
That all began to change in the 1930s, when there were new technical developments in synthetic materials like plastics, resulting in an explosion of choices for caster wheel materials. In particular, two rubber-like synthetic materials began to replace natural rubber.
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Neoprene
– This is a synthetic rubber made by the polymerization of certain chemicals such as chloroprene. It is an elastomer, meaning that when stretched it has a memory, and will return to its un-stretched position, much like rubber does. Unlike rubber, however, neoprene is highly resistant to grease, oils, harsh chemicals and high temperatures. This makes it an ideal material to use for caster wheels.
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Polyurethane
– is also a synthetic rubber. It is most often made by combining solutions of two or more chemicals, pouring the mix into a mold, and casting the desired product. Producers can control the properties of the final product by varying the ingredients of the starting compounds, and through different manufacturing processes. Caster wheels made from polyurethane can be fabricated with a range of hardness, from soft to extremely hard. Depending upon the formulation, polyurethane casters can resist oil, grease and chemicals quite well.
Both materials have come a long way since the 1930s, and are now widely available in many different styles for caster wheels. In fact, because of their superior properties, they have almost totally replaced natural rubber as a choice for caster wheels.
These days, it’s often hard to tell the difference between synthetic “rubber” materials and natural rubber itself. When many of our customers want soft casters, they’ll ask us for rubber casters. We usually ask questions about their application requirements, then recommend polyurethane or neoprene casters.
Below we’ll compare neoprene and polyurethane, with the goal of helping you decide which of the two materials is the perfect fit for your needs.
Neoprene Caster Wheels
One of the chief features of neoprene wheels is their smooth, quiet operation. Though they may seem soft, solid neoprene wheels are actually very durable. They are excellent for floor protection, and are frequently chosen as casters for office seating. They work well on many different floor surfaces, but will not mark or mar the floor. They are very quiet as they roll across office flooring, especially when compared to hard plastic casters used on some office chairs.
Another desirable feature of neoprene is its chemical resistance. This makes neoprene casters ideal for use in situations where oil or grease is present. Neoprene is not affected by water, steam or harsh chemicals.
For added strength, neoprene is often bonded to a harder core material. The outer layer of neoprene forms the wheel’s tread, while the core provides the structure.
Neoprene’s properties make it a popular choice in applications like these:
- Medical and laboratory equipment, such as medical carts and IV stands
- Carts for mobile computers
- Office furniture and seating, especially ergonomic chairs
- Harsh chemical wash-down areas, in hospitals or food processing facilities
Note that most of the uses mentioned above are for office, medical or light industrial settings. For heavy-duty industrial applications, polyurethane casters are popular. We’ll discuss those next.
Polyurethane Caster Wheels
It’s important to know that not all polyurethanes are equal – the material is available with a tremendous range of characteristics. During fabrication, manufacturers have many different chemical compounds to choose from, and various manufacturing processes which determine characteristics of the resulting products. They choose different polyurethane compounds, based upon the intended application situation. Is it important that the caster be non-marking, or make no audible noise? Will it be operated at low speeds or high speeds? Will it be used continuously, or only occasionally? Each of these situations may require a different polyurethane formulation.
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Non-marking
– while often considered to be non-marking and floor protective, polyurethane casters function better in this regard on some floors than on other floors. They work well on hard surfaces such as ceramic tile, concrete, or hardwood – but usually are not suggested for use on linoleum, vinyl or soft wood floors. Neoprene may be a better choice for softer flooring materials.
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Low-speed versus high speed
– as polyurethane casters roll, they flex as they load and unload while the caster is in motion. This constant loading and unloading causes internal heating in the polyurethane – and as speeds increase, so does the heating. If too much heat builds up internally, it can actually melt the polyurethane, leading to a failure called a “blowout”. To avoid this problem, the manufacturer will formulate a polyurethane able to withstand the heat generated by higher speeds. This means that if you are looking for casters to be used in a towline operation, make sure you choose models rated for the speeds at which your equipment will operate.
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Occasional versus continuous duty
– some polyurethane caster wheels, when under load and stationary (not moving) for long periods of time, may be prone to developing flat spots. To avoid this, manufacturers modify their compounds, and create polyurethane wheels that maintain their shape when loaded but not moving. If you need polyurethane casters for a heavy equipment cart that rarely moves, for example, be sure you choose casters that keep their shape.
Polyurethane or Neoprene: Can’t Decide? – Contact Douglas Equipment!
It’s great to have the multitude of choices that today’s modern caster materials provide us. Polyurethane or neoprene, either one can be tailored to create the best product for applications with specific demands. To find out which one would be the perfect fit for your requirements, please contact Douglas Equipment today. Phone us at 800-451-0030 (or 305-888-3700 in the Miami area), or contact us online through our contact form. We look forward to helping you decide!
