Polyurethane Rollers vs Rubber Rollers

The ‘wheels of industry’ are often in fact cylinders; the conveyor belt roller (or conveyor belt wheel) that underpins countless production and goods-handling processes. Is it time to move your thinking on rollers?

Millions of pounds worth of belt-type elevators, conveyors and turntables are bought each year in the UK, to move goods and materials around.

They feature in a highly diverse range of manufacturing, engineering, fulfilment and logistics operations. They are also used for brewery bottling lines, mining operations, mail sorting and airport luggage and cargo handling, to name but a few niche sectors.

Underneath those many miles of conveyor belts, are millions of humble but essential conveyor belt rollers. If this is something you don’t really think about, it may be time to take a fresh look at rollers. There could be far more efficient, durable and cost-effective alternatives, to make your conveyor line more productive.

Materials used to make conveyor belt rollers

In simple terms, a conveyor belt roller or sometimes referred to as a conveyor belt wheel is a metal cylindrical tube that rotates on a conveyor belt to allow objects to move across the surface. 

They are evenly-spaced rotating cylinders and are often covered in polyurethane for grip or to create a softer surface. Their purpose is to move material from one place to another using either gravity or a motorised system.

An increasingly popular roller to drive conveyors, elevators and turntables is commonly referred to as a ‘Poly roller’. This is one that optimises the incredible versatility and strength of polyurethane.

In some situations, making the right choice when specifying durable parts can mean deciding between polyurethane rollers vs plastic or rubber rollers.

Plastic and rubber are sometimes seen as the traditional, tried and trusted materials for this job, as they can be adjusted to match a multitude of roles, for rolls!

However, appreciation is growing for the way in which polyurethane can match – if not exceed – their advantages. Particularly to resolve the debate about Polyurethane versus Rubber as a roller, bush or wheel option.

Related article: Why polyurethane rollers out-perform other materials

Variance in belt roller properties based on material

As you would imagine, the dimensions of conveyor belt rollers are not the only things that change from location to location.

For instance, some rollers need to be extremely robust, to help move belts carrying large heavy objects, or rocks, stones, and concrete. Others need specific tensile features due to the delicacy or shape of the goods involved, or the speed of the belt they drive.

Rollers can be required to be housed vertically or horizontally and operate automatically or manually. The conveyors and turntables they support can be highly specialist too, with massive differences in the compression and tension they cope with.

It is no wonder then, that specifying this apparently ‘small’ part of your goods handling process can actually be a big decision.

Flex and bend

One of the common reasons to craft rollers from polyurethane, rubber or plastic is their weight values and elasticity. However, this is where plastic can lose out. It does not always hold its tensile strength in softer variations and can crack and break when it’s hard-moulded.

Rubber and polyurethane can be produced with enough ‘give’ to make roller sets run smoothly, and stay structurally unaffected by pressure. Yet they can still hold heavy loads brilliantly.

Resist at all costs

Rollers need to be able to operate efficiently in a wide range of processes, but also across diverse environmental factors. Rubber, plastic and polyurethane rollers all offer a good level of resistance to pollutants, chemicals and moisture. This is why in food manufacturing lines, plastic has largely replaced metal rollers, which can corrode and become unhygienic.

However, the choice that can truly ‘roll with the punches’ is polyurethane.

Its unique cell structure puts it in the top position due to its ability to withstand an incredible amount of wear, tear, and weathering. While rubber rollers could potentially warp in extreme heat, or crack and tear in extreme cold, polyurethane alternatives remain unaffected.

Rubber can also be affected by some chemicals, while polyurethane holds its integrity against many foes. By way of illustration, the simple application of some oils changes the textural properties and efficiency of rubber rollers. Polyurethane and plastic are both oil-resistant and shed its residue well.

Rubber also rots when exposed to moisture long term, which is not a fate shared by Polyurethane and plastic rollers.

Also read: Are Polyurethane Skateboard Wheels Good?

Bonding and sealing factors

All three options for rollers can be used in conjunction with other materials, such as metal or glass. However, polyurethane is once more the top performer when comes to adhesive and sealing functionality. Due to its chemical composition, it bonds well with other substrates.

Hardness and durability

If you need specific shore hardness ratings for rollers, then you could find that polyurethane is your only choice. It comes in anything from 10 Shore “OO” to 70 Shore “D”.

Of course, plastic can be hard too. However, it tends to crack, chip or even powder when friction is applied. Hard rubber rollers can also distort.

The combination of strength and elasticity to be found in polyurethane make it a long-lasting option for rollers, even when they operate around the clock and under intense pressure. While the others can wear down, polyurethane ‘rolls on’.

Clean, lean rolling machines

What about the relative properties of rubber, plastic and polyurethane rollers when it comes to moving tricky things along?

This is also when polyurethane can prove the best option, as it can retain structural integrity even when moulded into thin strands, or when it is cut into. So, it can be moulded and finished to fit intricate or challenging production processes.

Rubber’s carbon element limits its ability to be used in rollers that come into contact with products. It can leave black smudges on packaging materials, for example.

Keep reading: Polyurethane For The Car Industry

What are the advantages of polyurethane conveyor belt rollers compared to rubber?

When looking closely at conveyor belt rollers, it’s important we sum up just some of the ways polyurethane is advantageous.

Mention has already been made of its versatility. It can be blended and moulded into any tensile properties, including hard as metal or a soft foam roller.

In skilled hands, it can be created in pinpoint accurate form, with even intricate detailing for highly specialist polyurethane parts. Making any conveyor belt roller possible.

These would then be rollers that won’t bend, distort, split, crack, flake or become rough. Polyurethane is highly resistant to abrasion and pressure. It also holds its integrity in high-speed applications, extreme temperatures and moist environments.

This all adds to the incredible durability of polyurethane conveyor belt rollers, which are impervious to damage from contaminates and moulds, for instance.

Having access to parts with such incredible longevity can mean less downtime for your conveyor belts in the future, and less need for specialist repairs and replacements when a problem roller causes a knock-on effect.

Did we mention they are also quiet? Polyurethane offers valuable thermal and acoustic control properties.

Polyurethane vs Rubber for conveyor belt rollers

We’ve outlined the things you need to consider below before making a decision, so you can confidently choose the best material for industrial rollers that will suit your particular set-up.

Pros of Polyurethane Rollers

• High load capacity – Polyurethane wheels exhibit excellent load-bearing capabilities, making them suitable for heavy-duty conveyor systems. They can withstand heavy loads without significant deformation or failure.
• Superior abrasion resistance – Polyurethane has outstanding resistance to abrasion, outperforming rubber in terms of wear resistance. This makes polyurethane wheels ideal for demanding applications where high abrasion resistance is required.
• Impact resistance – Polyurethane offers good impact resistance, providing protection against shocks and impacts during conveyor belt operation. It helps minimise damage to the wheels and extends their lifespan.
• Wide temperature range – Polyurethane wheels can tolerate a broader temperature range compared to rubber. They remain stable and perform well across a wider spectrum of temperatures, including both low and high extremes.

Cons of Poly Rollers

• Higher cost – Polyurethane wheels generally have a higher upfront cost compared to rubber. However, considering their durability and extended lifespan, they can provide long-term cost savings by reducing the frequency of replacements.
• Potential chemical reaction – Certain chemicals or substances may have adverse effects on polyurethane, causing degradation or chemical reactions. It is important to consider the compatibility of polyurethane wheels with specific environments or substances they may come in contact with.

Read more:What is MOCA in Polyurethane?

Pros of Rubber Wheels

• Abrasion resistance – Rubber exhibits good resistance to abrasion, making it suitable for conveyor belt wheels that experience continuous contact with the belt and the conveyed materials. It can withstand the wear and tear caused by friction and impact.
• Shock absorption – Rubber has excellent shock absorption properties, which helps reduce vibrations and impacts that occur during conveyor belt operation. This feature prevents damage to the belt and extends its lifespan.
• Traction – Rubber wheels provide good traction between the wheel and the conveyor belt, ensuring efficient and reliable movement without slippage. This feature is particularly important when dealing with heavy loads or inclines.
• Cost-effective – Rubber is generally more cost-effective compared to other materials, making it a preferred choice for conveyor belt wheels, especially in applications with less demanding requirements.

Cons of Rubber Rollers

• Limited load capacity – Rubber has a relatively lower load-bearing capacity compared to some other materials. In heavy-duty applications, rubber wheels may not be suitable for handling extremely heavy loads or prolonged high-pressure situations.
• Temperature sensitivity – Rubber can be sensitive to extreme temperatures, particularly high temperatures. Continuous exposure to heat can cause degradation and reduced performance of rubber wheels.

Cost implications

With such an impressive list of reasons to prototype parts in polyurethane, your next question is likely to be whether this would represent a significant cost increase on your usual rollers.

Plastic, rubber and polyurethane rollers can all be precision machined and moulded to match specific dimensions and to slot into place within any machine. Which option can be rated as the best value for money?

Well, for one thing, commissioning rubber rollers to fit can be more expensive than the other two alternatives. Also, the durability of polyurethane is a key point, as rollers made from this will last longer and will therefore not have to be replaced as often.

It all means that for many, diverse operations, companies ‘come around’ to specifying polyurethane rollers!

The answer is likely to be no! From prototyping to universally accurate production orders, the team at Custom Moulded Polyurethane can keep unit prices surprisingly low. That’s because polyurethane is a low-cost material, and we have the skills and machinery to handle it adroitly.