Trendgineering
Respiratory masks made of LSR are valuable helpers in times of Corona
| Petra Rehmet
Maximum precision with SilcoSet and APC plus
People seriously ill with COVID-19 often need artificial respiration. The global demand for devices and accessories, such as breathing tubes, filters and also respiratory masks is therefore rising. The material LSR (Liquid Silicone Rubber) is ideal for this application, particularly for flexible components with direct contact to the patient's skin.
The material LSR is taking over an important role in the battle against the COVID-19 virus because it is temperature-resistant, sterilizable and even resistant to bacteria. During the production of flexible components for respiratory masks, in particular, it displays its advantages. This mainly involves the elastic seals at the sides of the masks or in the nose area that guarantee optimum isolation and thus safety in the oxygen supply to the patient. If these components are made of LSR, they have numerous advantages. Thanks to their high temperature resistance, they can be cleaned with steam and sterilized. Sustainable multiple usage is thus possible. Furthermore, they are free of any plasticizers, which is particularly important because these elements make direct, constant skin contact with the patient. LSR components thus offer clear advantage in comparison with other materials such as thermoplastic elastomers (TPEs).
But also breathing masks or protective goggles with a silicone edge are excellently suited thanks to the good fit of the elastic silicone material. LSR can also be molded together with other thermoplastics such as PBT or PC as a multi-component application and is thus ideal for a combination of housing and seal on the skin.
SilcoSet and APC plus ensure maximum precision
LSR, however, has an extremely low viscosity and therefore requires particularly high precision and process reliability during injection. SilcoSet technology makes KraussMaffei's hydraulic, electric and hybrid machines with clamping forces of 250 to 420 kN suitable for silicone processing – even as a retrofit. For processing silicones, the clamping unit must close reliably and seal the mold absolutely tightly with positive locking – which is no problem for the two-platen technology from KraussMaffei. The dosing-injection unit provides for high-precision injection and exact nozzle shut-off for optimal component quality.
This precision can be increased even more with the machine function APC plus (adaptive process control). APC compensates for the batch fluctuations commonly encountered in LSR processing. As the process progresses, the machine function monitors the viscosity of the material and corrects the filling volume even in the shot. The process as a whole is made even more precise; the part weight remains constant. Digital solutions such as DataXplorer or EasyTrace from KraussMaffei provide further support and guarantee perfect tracking of the processes and quality control.
With the SilcoSet technology, APC plus and digital solutions for traceability, KraussMaffei guarantees extremely high process reliability and product yield in the processing of LRS – fast, flexible and all this combined with high unit counts – and thus offers valuable support in the framework of the rising demand in the times of Corona.
Major advantages LSR:
- Ideal for injection molding and thus suitable for reproducible mass production
- Biocompatible and plasticizer-free
- Suitable for permanent skin contact
- Elastic, adapts to the facial contour
- Sterilizable, withstands very high temperatures and steam pressures
- Numerous formulations with BfR and FDA approval available on the market
- Suitable for multi-component injection molding with other thermoplastics