At Fakuma 2026, the WACKER Group will showcase its non-postcure liquid silicone rubber with self-adhesive properties for the first time.

ELASTOSIL LR 5471 is an addition-curing material consisting of two components that are mixed together before processing. It crosslinks to form an elastomer with an extremely low volatile content.

As a result, hard/soft composite parts made from the new grade can be used in the food and medical industries as well as in infant care, in many cases even without postcure treatment. The product is available in Shore A hardness grades 40 and 50.

Among other things, ELASTOSIL LR 5471 is suitable for food contact applications such as cookware, baking and kitchen utensils.

This self-adhesive liquid silicone rubber makes the manufacture of hard-soft composite components very efficient. Vulcanized parts made from this material can be used in medical technology or in applications involving food contact without the need for time-consuming thermal post-treatment.

Allows efficient large-scale production

Self-adhesive liquid silicone rubber grades allow hard/soft composite components to be produced very efficiently in large-scale production runs.

Internal bonding agents added to the silicone polymer ensure strong and reliable adhesion to the substrate. Ideally, the hard component can thus be overmolded with liquid silicone rubber in the injection molding machine without any surface treatment.

This facilitates the cost-effective mass production of composite parts based on thermoplastic or metal materials.

Excellent adhesive strength

ELASTOSIL LR 5471 achieves excellent adhesion on metals and thermoplastics. In tests conducted by the company, the product achieved an adhesive strength to polybutylene terephthalate (PBT) of 28 N/mm (according to ISO 813). Similar results were achieved on polyethylene terephthalate (PET).

Eliminating thermal post-treatment step

Standard liquid silicone rubber grades usually require thermal treatment for several hours in order to meet the requirements for a number of sensitive applications. But with additional processing step during manufacturing, ELASTOSIL LR 5471 does not require thermal post-treatment.

BfR compliant measurements of test slabs with a thickness of 2 mm heated for 4 hours at 200 °C show that the specified volatile content of the cured silicone is less than 0.4%. As a result, the product complies with the guidelines of the German Federal Institute for Risk Assessment and other regulations governing food contact even without thermal post-treatment.

High mechanical strength

Another advantage is the product’s mechanical performance. ELASTOSIL LR 5471 exhibits an elongation at break of up to 570% and a tear strength of 38 N/mm (according to ASTM D 624 B).

Thus, non-postcured parts provide enough sufficient elasticity and mechanical strength for mechanically highly demanding applications. Examples include gaskets and flexible scrapers for cookware, baking and kitchen utensils, liners for medical masks, therapeutic devices, and soft components for pacifiers and baby bottles.