Playing it safe – minimising the proportion of volatile constituents in silicone components
Developed by Starlim Spritzguss GmbH from Marchtrenk in Austria, starlim Carbon Dioxide Cleaning is a unique process that has now been launched on the market. The specialist for liquid silicone employs SCD-Cleaning during production of silicone components that need to meet very specific requirements regarding the residual content of volatile components. “The proportion of volatile constituents usually exhibited in silicone components lies between 1,500 and 3,000 ppm”, emphasises Head of Development Leopold Pühringer, drawing on his own experience in this area. “SCD-Cleaning enables us to reduce this proportion below the detection limit, which is an enormous advantage for customers!”
Typically speaking, not all volatile components such as silicone oils and cyclic siloxanes are incorporated into the polymer during curing of silicones. Their proportion lies between 1,500 to 3,000 ppm, depending on the silicone type involved. The majority of volatile components cannot be eliminated through tempering, a process employed to achieve desired mechanical properties. The proportion drops during this by a factor of about 10 to around 200 to 400 ppm. But the unique SCD-Cleaning process from starlim reduces the proportion of volatile components even further by more than a factor of 10. “The proportion of volatile components lies below the detection limit following SCD-Cleaning, meaning less than 20 ppm”, elaborates Leopold Pühringer. For all components which do not need to be tempered, SCD-Cleaning on its own is sufficient to lower the proportion of volatile components below the detection limit.
The key feature of the SCD-Cleaning system is that, as a “super pure” process, it can even be employed for silicone components intended for medical applications where the complete prevention of contamination is vital. The system is, basically, an enormous washing machine that has been adapted by the manufacturer to meet starlim’s requirements exactly. CO2 is applied under pressure to silicone components during “washing”, thus freeing them of volatile constituents. “The SCD-Cleaning system represents a further expansion of our enormous expertise in the field of silicone processing. In addition to offering customers in the mobility, electronics, lifestyle or medical sector individually designed components, we also treat these appropriately to ensure that volatile constituents are almost completely eliminated. And we offer all this at an extremely attractive price”, stresses Leopold Pühringer.