Silicone tube manufacturing lies in its advantages of extrusion technology. The use of extrusion as a physical manufacturing technology for silicone tube is much better than the past hot pressing or hot punching technology. Together with the new process technology of extruding silica gel, it can be shaped in liquid state using CO2. The so-called re-developed process in silica gel production combines the advantages of physical extrusion and chemical manufacturing. Like a chemical foaming masterbatch, the raw material silica gel is fed into the extruder through a granular hopper.

There is no need to modify the extruder itself. Another benefit is that as a physical foaming agent, dry ice does not leave any residues, such as reaction squeeze water. Therefore, it is also suitable for hydrolysis-sensitive materials. The new metering technology can feed dry ice particles directly into the feed zone of the extruder through the metering screw and gravity mixer. In this way, the IKV research team was able to avoid premature dry ice sublimation and cooling of plastic particles. Through the rapid melting of the plastic and rapid pressure, the dry ice is dissolved in the melt. IKV has extensively tested new metrology technologies and developed relevant process windows.

With the new process technology, silica gel density of 350-950 kg/m? (such as LDPE) is achievable, which is comparable to chemical silica gel. By adjusting the process temperature, this method can also be applied to other plastics such as polypropylene. Despite the relatively high sublimation loss in the blowing agent metering, the process can compete with chemical blowing agents due to the lower cost of CO2. This process allows cheap entry into foam extrusion because any modification is limited to metering technology. It can integrate a variety of technical advantages into the production process of today's silica gel.