Wacker to show self-adhesive silicone rubber at Fakuma

Wacker will showcase Elastosil LR 5471, described by the company as the first non-postcure liquid silicone rubber with self-adhesive properties, at the Fakuma international trade fair for plastics processing. The product crosslinks to form an elastomer with very low volatile content. According to Wacker, this enables hard/soft composite parts made from the grade to be used in food and medical applications as well as in infant care, in many cases without postcure treatment. The material is intended for efficient production of composite parts combining thermoplastic or metal substrates with silicone rubber. Wacker will present Elastosil LR 5471 at Fakuma from October 12 to 16 in Hall A6, Booth A6-6212.

Self-adhesive liquid silicone rubber grades allow hard/soft composite components to be produced efficiently in large-scale production. Internal bonding agents added to the silicone polymer provide strong and reliable adhesion to the substrate. In an ideal process, the hard component can be overmolded with liquid silicone rubber in the injection molding machine without surface treatment. This supports cost-effective mass production of composite parts based on thermoplastic or metal materials.

Adhesion to metals and thermoplastics

Elastosil LR 5471, which Wacker is introducing for the first time at Fakuma, is designed to provide adhesion to metals and thermoplastics. In tests conducted by the company, the product achieved an adhesive strength to polybutylene terephthalate (PBT) of 28 N/mm, measured according to ISO 813. Similar results were obtained on polyethylene terephthalate (PET).

Standard liquid silicone rubber grades usually require thermal treatment for several hours in order to meet requirements for a range of sensitive applications. Wacker states that this is not required for Elastosil LR 5471 due to an additional processing step during manufacturing. Measurements compliant with BfR requirements on 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 below 0.4 percent. 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.

Mechanical properties and applications

Wacker also points to the mechanical performance of Elastosil LR 5471. The material exhibits an elongation at break of up to 570 percent and a tear strength of 38 N/mm, measured according to ASTM D 624 B. According to the company, non-postcured parts therefore provide sufficient elasticity and mechanical strength for mechanically demanding applications.

Examples cited by Wacker 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.

Elastosil LR 5471 is an addition-curing material consisting of two components that are mixed together before processing. It is available in Shore A hardness grades 40 and 50. Wacker states that the product is particularly well suited for the large-scale production of overmolded parts and for co-molding procedures.

Wacker is presenting Elastosil LR 5471 for the first time at Fakuma. 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

Presentation at Fakuma

More details will be provided during Wacker’s presentation at Fakuma’s East Conference Center, Berlin Room, on Tuesday, October 13, at 2:20 p.m. Michael Kalchauer, head of Wacker’s Process Technology Center, will discuss the unique selling points and processing benefits of Wacker’s silicone rubber grades, including Elastosil LR 5471.

Wacker will exhibit at Fakuma 2026 in Hall A6, Booth A6-6212.