Frequently Asked Questions

Kalrez®

For processes that involve using steam, what grade of Kalrez® should I use?
The most effective grade for use with steam is Kalrez® 6375. This grade offers very high resistance to hot water and steam at temperatures of up to 275°C.

What grade of Kalrez® should I use with hot amines?
Kalrez® Spectrum 6380 boasts excellent resistance to chemicals at maintained temperatures of up to 225°C. This elastomer was designed with aggressive amines in mind.

Which Kalrez® product is best suited for use with rapid gas decompression (RGD)?
For the best results with RGD, use Kalrez® 0090. During MERL tests, this material gained the maximum score of 0000!

How suitable is Kalrez® for use in high temperature applications?
Almost all grades of Kalrez® can tolerate temperatures of around 250°C but there are certain grades capable of withstanding much more intense heat. Kalrez® 7075 has the highest threshold and can operate at temperatures as high as 327°C.

Can Kalrez® operate at low temperatures too?
Most grades of Kalrez® can resist low temperatures, with Kalrez® 0040 being suitable for use in temperatures as low as -42°C.

Is Kalrez® approved by any official bodies?
Materials Engineering Research Authority Ltd (MERL) has approved Kalrez® 0090 to NORSOK M-710 standard. This polymer achieved the highest possible rating of 0000.

Viton®

What is Viton®?
The word "Viton" has become shorthand within the seals industry in a similar way to how words such as Hoover or Tannoy have come to represent their respective products, but it is important to remember that Viton® is in fact the trade name for one of Dupont Performance Elastomers' fluropolymer elastomers.

What is Viton®'s upper temperature limit?
The upper limit for Viton® is around 200°C, but this can often go higher depending on the application. It is best to check with your supplier and provide full application criteria.

Is Viton® resistant to steam?
As the stated upper limit for Viton is 200°C and water turns to steam at 100°C, you would think this wouldn't be a problem, but unfortunately the reality is not what you might expect! Owing to the crosslinking make-up of standard Vitons®, a number of the components react badly to steam, causing a phenomenon known as hydrolysis which can destroy the polymer chain over a period of time. There is a variation of Viton® known as Viton® APA which offers substantially better resistance to steam.

What variations of Viton® are available?
Aside from the standard Viton® range, there are two main variations on the material: Viton APA, which offers improved chemical resistance and outstanding thermal properties, and Viton ETP (Extreme) which is resistant to even the harshest environments and most caustic chemicals. Both Viton APA and ETP are produced using Advanced Polymer Architecture.

Which APA grade is the most resistant to steam?
All grades are resistant to steam and show minimal swell, with the best resistance being offered by the GF-S grade. This grade maintains strong performance up to 150°C, although any temperatures higher than this can affect performance severely.

What are the temperature limits of Viton® APA and Extreme?
The temperature limits are much the same as the rest of the Viton® range - the upper limit is around 200°C and the lower is around -40°C. The improvements in resistance are more to do with the chemicals that each can withstand, rather than temperatures.