- Accurate production control
- Significant savings from reduced energy consumptions
- Improved end-product quality
XL7-HT Viscometer |
VP550 Signal Processor |
Silicone Rubber Manufacturing Process Overview
Silicone rubber, produced in grades such as 107 and 110, is a versatile elastomer used in sealants, adhesives, moulding compounds, insulation products, and a wide range of industrial components. These base materials differ mainly in molecular-weight targets and end-use performance, but both rely on tightly controlled polymer-building steps during production.
Industrial silicone rubber manufacturing follows three core unit operations: evaporation, distillation, and polymerisation.
An organosilicon feedstock is prepared, then routed through a falling-film evaporator to remove light volatiles and adjust the material concentration. A downstream distillation step further separates low-boiling components and standardises the feed quality, ensuring a consistent input to the polymerisation stage.
From here, the process diverges depending on grade.
110 silicone typically undergoes filtration and transfer to a reactor where polymer growth is driven using a catalyst and capping agents, giving controlled chain length and flow characteristics
107 silicone is usually taken from the lower fraction of the distillation system and pumped directly to a polymerisation kettle, where an alkaline catalyst drives the molecular-weight build and neutralisation sequence
Across both production lines, viscosity is the primary real-time indicator of polymer development. As chain length increases, viscosity rises, providing a direct measure of reaction progress and product specification, making it a critical parameter for real-time process control.
Process Challenges
Silicone polymerisation is highly sensitive to temperature variation, catalyst efficiency, water content, and impurity levels. Small deviations in these factors can rapidly alter the kinetics of chain growth, leading to viscosity drift, incomplete polymerisation, or excess chain scission. Because molecular weight is directly tied to performance characteristics such as elasticity, tensile strength and thermal stability, tight control is essential.
Traditional laboratory viscosity testing provides quality confirmation, but lacks immediacy. Sampling, cooling, and offline measurement introduce delays that prevent operators from detecting reaction shifts when they occur. In fast-moving polymerisation systems, this can result in off-spec batches, longer reaction times, unnecessary energy consumption, or inconsistent material performance.
Inline measurement provides direct visibility into the reaction as it happens. Real-time detection of viscosity drift enables operators to adjust catalyst dosage, temperature profiles, or reaction time before quality deviations develop. Continuous monitoring also improves batch-to-batch repeatability and stabilises production during transitions between grades or feedstock variations.
Inline Viscosity Monitoring Solution
XL7 viscometers are installed directly in silicone production lines, either inside the polymerisation kettle or within the circulating pipelines. Installation within the vessel allows real-time tracking of viscosity as the polymerisation reaction progresses, providing an immediate indication of molecular weight development. Real-time visibility of reaction progress also means the reaction can be quenched during the narrow completion window.
Because viscosity directly reflects the extent of polymer chain growth, the XL7 gives operators precise, actionable insight into the reaction. Production schedules can be optimised based on live data, reducing over-processing, lowering energy consumption, and ensuring consistent end-product quality. Continuous measurement also supports improved process control during scale-up or when transitioning between 110 and 107 silicone grades.
XL7 High Temperature |
VP550 Signal Processor |
Hydramotion sensors are all-welded solid state sensors, designed to operate at the fluid temperature and can be configured to display viscosity corrected to a standard reference temperature if required. All XL7's are fully configurable based on desired installation requirements, process conditions and hazardous area requirements. Sensors are orientation independent and measurement is unaffected by tank or vessel size. All that is required is a suitable mating process fitting.
There are no moving parts to replace or service, along with the unwelcome downtime. Instead, there is negligible maintenance and an unbeatably low cost of ownership.
Typical dimensions can be seen above for an indicative XL7 sensor. Hydramotion also offers a bespoke design service - Special Ops - where a sensor of virtually any size or geometry can be designed to fulfil the requirements of the application.
Ready to learn more?
Contact Hydramotion to discuss your silicone application requirements. Or visit the following link to learn more about Hydramotion viscosity sensors.