News and Press Releases
27 July 2017
WACKER Presents Heat-Resistant Solid Silicone Rubber for the Household-Product and Automotive Sectors

WACKER, the Munich-based chemical company, will be premiering its new ELASTOSIL® R plus 4350/55 solid silicone rubber at this year’s international trade fair for plastics processing Fakuma. An outstanding property of this extrudable and addition-curing silicone grade is its high resistance to heat. Heat stabilizers enable the solid silicone to withstand temperatures of up to 300 °C for several days, without any substantial modifications to its elasticity or mechanical properties. Even temporary peaks of up to 400 °C pose no problem. The new solid silicone is therefore suitable for components used in oven and stove doors or in engine compartments, for example, which are exposed to heat repeatedly or over lengthy periods. Fakuma will be held in Friedrichshafen, Germany, from October 17 to 21.

ELASTOSIL® R plus 4350/55 is a silicone rubber for formulating heat-resistant, addition-curing silicone elastomers. It reveals its properties to optimum effect in combination with heat stabilizers of the ELASTOSIL® AUX STABILIZER H series which are added to the base rubber. The type of stabilizer and the amount used have a significant influence on the thermal properties of the cured rubber. The silicone grade is easy to process in extruders.

ELASTOSIL® R plus 4350/55 can therefore be used to make extremely heat-resistant tubing and sealing profiles that withstand temperatures of up to 300 °C for several days – and even temperatures of up to 400 °C for short periods – without any damage. Heat tests at 200 °C and 300 °C, respectively, show that key mechanical properties such as Shore hardness and elongation at break change very little even after 2,000 hours, i.e. 80 days. In this way, manufacturer’s specifications for products such as the sealing profiles used in modern ovens are clearly exceeded.

After it has cured, ELASTOSIL® R plus 4350/55 achieves a Shore A hardness value of 55 which is ideal for manufacturing heat-resistant profile gaskets, such as for oven and stove doors or for engine-compartment parts. The new silicone rubber also features good resistance to superheated steam. Consequently, seals made of ELASTOSIL® R plus 4350/55 can also be used in applications that require resistance to both heat and superheated steam. Carefully post cured grades comply with the requirements of the German Federal Institute for Risk Assessment (BfR) and the US Federal Drug Administration (FDA) for food contact.

WACKER supplies ELASTOSIL® R plus 4350/55 as a base rubber blend without additives such as colorants or heat stabilizers. As a result, processors can customize the rubber blend exactly to the specific application. In this regard, WACKER can provide processors with an extensive portfolio of additives.

For more information:  www.wacker.com