Not All Rubbers Are Created Equal


Why Test houses want full disclosure of elastomer contents and why you should too!


Commercial Quality Rubber and Regrind, Do you really know what you’re buying?

When you buy rubber sheet or specify Rubber parts you usually say “I want X rubber in Y hardness” but do you question your supplier as to where your rubber was made and what its composition is?

Unless you specify a specific rubber grade like BS271 or BS2752 you will be quoted and given Commercial Quality Grade Rubber and that’s where your problems could be starting. Do You Really Know What You Are Buying?


Is there a reason why many CQ (Commercial Quality) grade materials on the market are so inexpensive?

In a highly competitive market, price is a large part of the buying equation. For economic reasons these rubber products are heavily loaded with fillers and reground ingredients which are low cost and generally derived from used/recycled tyres. Additives of this nature significantly degrade the materials performance characteristics. When cured rubber is blended, there will be inconsistencies across the material creating weak patches in the physical structure. In the case of a CQ Nitrile for example the oil would find this weakness causing swelling and potential failure of the seal.


Do these low priced sheets meet the specifications usually advised?

Due to the inconsistencies created [see above] it is very difficult for any CQ grade product containing these additives to meet specifications let alone be tested for resistance or physical characteristics. This is regardless of the distributors/manufacturers claim of % synthetic element contained in the sheet.


How can I be assured that these ‘Commercial Quality’ grade materials are suitable for our application?

There is no way to be 100% sure that a product containing regrind will perform satisfactorily under standard applications. For example, Nitrile [NBR] has excellent resistance to petroleum oils and aromatic hydrocarbons, mineral oils and many acids. As soon as an element of regrind or regenerated filler is added the benefits of the polymer are significantly reduced. We advise strong caution when using any commercial grade sheeting’s for select applications relating to base polymers.


Why are low priced sheets heavier?

The specific gravity of the regrind and fillers is much higher than the polymer content that the products are supposed to contain. As a general rule the more filler you use the heavier the product becomes.


Why do most ‘Commercial Quality’ grade materials have such a strong odour?

The use of high levels of regrind rubber is generally the reason for the strong odour. The cheap oils and chemicals used to process and break down the fillers from a cured to an uncured state amplifies this.



Ask yourself this...

High levels of regrind material significantly degrade the physical properties and performance of the material. You must ask yourself the following questions: Do you really know what you are getting? Are you really making a saving? With today’s ‘claim culture’ can you really take the risk with an inferior commercial grade polymer? What are the true risks and consequences of using a material not fit for purpose?


What makes us unique?

Due to EMI Seals & Gaskets Ltd continuing involvement in the design, development and manufacture of Seals, Gaskets, O Rings and Shielded Products for IP, ATEX, IECEx, NEMA and other Certified Applications we have become very aware of the potential dangers and short comings of using Commercial Quality compounds. Working with both customers and Certified Test Houses around the world, but especially SGS BASEEFA in Buxton, England (probably the most respected Test House in the world in this area of testing), we have developed a range of materials and compounds that are fully compliant with all the latest compounding and traceability parameters required.


Is it worth the risk?

In today’s claim sensitive culture your product failure could cost not only life or limb but also your company’s reputation and incur punitive charges just by buying an inferior and possibly dangerous rubber material. Why take a risk with your products integrity and your company’s reputation, what would the ultimate cost be if you had to recall a batch of products because 11 months on, the seals in your product were failing?

Does the material you’re buying have the latest RAPRA approvals for Resistance to UV or have their own IECEx report on Ingress Protection (IP) or Thermal conditioning? Can your Seal and Gasket supplier offer that level of assurance in what you’re buying and specifying?

There may be a cost difference and if it is upwards we will do our best to minimise any impact but in return we can supply you with a product that is REACH/RoHS/PAH/CE Certified so that you have confidence in what you are buying is what you are getting and in turn you can give your customers confidence that they can have rely on you and your product.


The next steps

We would strongly advise that you check with your current supplier with regards to recycled elements in your sheeting. If the material emits a strong odor and when cut internally has a ‘grain’ affect and fine inclusions or has an uneven surface finish, then the likelihood is you are receiving a regrind rubber material.

If you would like to learn more about the global impact of Regrind or would like to discuss how we can help protect you from the dangers, please contact our relationship management or technical teams via email:, through our contact form, or via our contact page.