Silicone rubber is generally softer, has better extrusion effect, is easy to operate, and can be extruded into products of various shapes and sizes. Its processing equipment and tools are basically similar to those of ordinary rubber.



The extruder generally uses a single-thread screw of Φ30 or Φ65mm, and the aspect ratio is (10~12) : 1 for better effect. Try to keep the temperature low during extrusion, preferably not exceeding 40℃, so both the barrel and the screw must be cooled with water. For products with higher quality requirements, an 80~140 mesh filter can be installed near the head to remove impurities in the rubber and improve the extrusion quality.

Silicone rubber extrusion semi-finished products are soft and easy to deform, so they must be vulcanized immediately. The most commonly used method is hot air continuous vulcanization; the wire and cable industry usually uses high-pressure steam continuous vulcanization. If continuous vulcanization cannot be performed after extrusion, in order to prevent deformation, it should be immediately picked up with a disc, drum or conveyor belt after extrusion, and isolated with talcum powder to prevent mutual adhesion. If the rubber is found to be too soft and not suitable for extrusion, 3 to 5 parts of fumed silica can be mixed into the rubber.

For the rubber formula used for extrusion, the amount of vulcanizer should be appropriately increased compared to that of molded products. The extrusion speed of silicone rubber is lower than that of other rubbers. When the same extrusion speed as other rubbers is required, a higher screw speed should be used.

pls check General Purpose Fumed Extrusion Silicone Rubber