Rubber materials

Rubber materials used for gaskets are based upon a polymer which is blended with additives to give each formula unique properties. A rubber material tailor-made for a specific end use is seldom appropriate for use in other applications. For technically more advanced products, specially developed materials meet specific requirements

The most important ingredient is the polymer, which may be from 15 to 70% (usually around 50%) by weight of the final mix.

A typical formulation is based upon:

Polymer 50%
Fillers 40%
Softener 5%
Activators 2%
Curative 1%
Accelerators 1%
Antioxidant 1%

Rubber materials from WCR are specifically selected and designed for PHE applications.

Gradually all rubber materials age. This means they loose their original properties, and makes them unsuitable for further use. The rate of ageing depends on the original quality of the product and the environment. Liquids and chemicals, their concentration and temperature affect the degradation process. Also variation in temperature and pressure influence the performance and lifetime of a rubber product.

Chemical resistance
Each rubber material has its unique resistance towards various chemicals. Polymer and additives are carefully selected to meet different needs and facilitate optimal performance.

High temperature
At high temperatures, the rubber material will be attacked faster by surrounding chemicals and oxygen in the atmosphere. The oxidation process will either make the rubber harder or make it softer, or even a combination of both. Therefore the selected type of rubber material must be resistant to the temperature in the application in order to maintain good performance and meet stated lifetime.

Low temperature
At low temperatures stiffness increases, and elasticity decreases. This change influences the sealing force of the gaskets. All rubber materials have a certain lowest temperature that has to be exceeded to be able to perform well enough as a gasket.

Food applications
For food applications there are demands according to national standards. The leading framework for PHE gaskets is the FDA standard (Food and Drug Administration, USA). This standard regulates which additives are allowed to be used in the rubber and to which extent. It also sets demands on what tests have to be done and approved results to ensure compliance with the standards.

Robust development, compounding and production are the keys to WCR Quality