Qacker will be premiering its novel Elastosil LR 3078 product series at K 2022 International Trade Fair for Plastics and Rubber. These self-adhesive liquid silicone rubber grades cure extremely fast and establish a firm bond with the thermoplastic polycarbonate without the need to pretreat its surface. Elastosil LR 3078 was designed for two-component injection molding and enables cost-effective large-scale production of multicomponent parts, such as those needed in medical technology and the automotive industry. This year’s K show will take place in Düsseldorf, Germany, from October 19 to 26.
With Elastosil LR 3078, Wacker is expanding its portfolio of self-adhesive liquid silicone rubber with a product line that adheres specifically to polycarbonate. The grades in this series are formulated in such a way that, as they cure, chemical adhesion builds up to the substrate, but not to the injection molding tool. To this end, Wacker uses a newly developed and patented self-adhesive technology that does not contain any bisphenol A structures. By eliminating this substance class, the company increases occupational safety and contributes to consumer protection.
All grades of the new product line can be easily processed by two-component injection molding. They do not contain any substances that could result in solid deposits forming in the mold during processing. This ensures that the injection molding machine runs without interruptions.
Adhesion tests show that Wacker’s new self-adhesive silicone rubber Elastosil LR 3078 adheres firmly to polycarbonate without pretreatment. (photo: Wacker)
Thanks to the fast curing of the new liquid silicone rubber grades, injection molding cycle times are very short. In addition, devices with complicated geometric shapes can be produced with high precision and without the need for secondary finishing. Elastosil LR 3078 thus opens the way for further miniaturization of polycarbonate-silicone hybrid parts and for completely new product designs.
The Elastosil LR 3078 product line comprises the hardness grades 20 to 70 Shore A and thus covers the entire hardness range that is important for the soft component of hybrid parts. All grades are translucent and can be colored as desired. The cured products are characterized by very good mechanical properties. They achieve a very low compression set. This is ideal for sealing applications. When relaxed after being compressed at high temperatures, a part molded with Elastosil LR 3078 will only show a small amount of deformation remains thanks to the material’s elasticity. Sealing lips made of Elastosil LR 3078 therefore retain their function over the long term.
Cured Elastosil LR 3078 products have passed selected tests for biocompatibility according to ISO 10993 and US Pharmacopeia Chapter <88>, Class VI. They can also be steam-sterilized repeatedly at 134 degrees Celsius with no loss of mechanical properties or adhesion to polycarbonate. The new liquid silicones are therefore also suitable for manufacturing two-component parts for medical devices.
Elastosil LR 3078 can be used in all industrial sectors. Appli-cations range from transparent covers as needed in motor vehicles, to housing covers for household appliances, to systems for medical diagnostics, automated drug delivery and minimally invasive diag-nostic and surgical techniques.
The new self-adhesive silicone rubber Elastosil LR 3078 makes the manufacture of multicomponent devices, e.g. for respiratory masks, very efficient. (photo: Wacker)