Silicone tubing, as a highly elastic, high-temperature, and corrosion-resistant flexible connector, is widely used in the medical, food, automotive, and electronics industries. Its production process is rigorous, ensuring material purity, dimensional accuracy, and long-term stability.
Raw material preparation is the first step in production. Medical or food-grade silicone tubing typically uses high-purity vinyl methyl silicone rubber (VMQ) as a base material, supplemented with additives such as silica and hydroxyl silicone oil to enhance strength and flexibility. The raw materials must be dried to prevent moisture from affecting vulcanization.
The mixing process is crucial for uniformly blending the silicone rubber and additives. Mixing is performed in an internal mixer or open mixer at a specific temperature (typically 120-180°C) to ensure uniform dispersion of the filler and avoid excessive shear that could break the silicone rubber molecular chains. The mix needs to rest for several hours to eliminate internal stresses and improve subsequent processing performance.
Extrusion is the core step in silicone tubing production. After filtering, the rubber mix is pressed into a mold through a screw extruder and continuously extruded at high temperatures (approximately 150-200°C) into a preformed tubular product. Mold design directly affects tube wall thickness and inner diameter accuracy, requiring adjustments to the compression ratio and flow path structure based on specifications.
Vulcanization and curing impart final properties to the silicone tubing. The extruded semi-finished product undergoes high-temperature steam vulcanization (typically 180-220°C for 30-60 minutes) or platinum vulcanization (an odorless and environmentally friendly process) to cross-link the silicone rubber and form a three-dimensional network structure, imparting aging and tear resistance. Some products also require a secondary vulcanization for further stability.
Post-processing includes trimming, inspection, and packaging. Dimensional tolerances are checked using a laser caliper, defective products are manually screened, and sterilization is performed (for medical-grade products, compliance with ISO 10993 is required). The final silicone tubing is sealed and packaged in coils or strips and stored in a dry, dark environment. The entire process requires extremely high equipment precision and operational standards; deviations in any step could impact product lifespan and safety. With advancements in materials science, high-end products such as low compression set and highly transparent silicone tubing are becoming a research and development hotspot.