Extrusion molding process is usually vulcanized by hot air, steam or liquid medium. Hot air curing generally adopts hot air tunnel, the drying tunnel temperature is 300-650 ° C, and the curing time is 3-12 seconds. The recommended curing agent is bis-24 or additive curing agent, both of which can provide rapid curing performance without bubbles.

Steam vulcanization is usually used for the processing of wires and cables. The diameter of the steam box is 100-150mm, the length is 30-50m, the steam pressure is 3.5-15bar, the liquid medium is vulcanized, and the extruded silica gel is usually immersed in the molten liquid (salt or lead). Double 24 is used to avoid bubbles.

Secondary vulcanization

The purpose of the primary curing process is to remove the low volatile matter produced in the curing process and the by-product of the perchloric curing agent in the silica gel. Secondary vulcanization can make the product size more stable and improve its temperature resistance. Used in the production process of using peroxide as curing agent; It is recommended to conduct secondary vulcanization to remove acidic by-products, especially when the final application ambient temperature is high. Both electric heating and high-temperature gas heating ovens can be successfully used in the secondary vulcanization process. For every 100 kg of silica gel product, it is recommended to maintain at least 100 L/min air flow in the oven. During the secondary curing process, the exposure area of the product should be increased as much as possible. It is recommended that the set temperature of the oven should be at least 100 ° C higher than the actual working temperature. For products with a thickness of more than 2mm, it is recommended to use the method of gradually increasing the temperature to reduce the problem of blistering on the product surface.