Silicone rubbers calendering

Silicone rubber compounds can be molded, extruded and calendered. The vulcanisation of rubber compounds occurs in two stages 1) in a press or steam boiler at high pressure and 120-150 °C 2) by thermostatic control at atmospheric pressure and 200-250 °C. 

SE-. [GE Silicones] Silicone rubber compds. for conq)r., transfer, and inj. molding, extrusion, calendering, o-tings, cylinder lino seals, hydraulic seals, valve gaskets, tubing, belting, shock mounts, tolls, closed cell qxxige, coated fabrics. 

Silastic . [Dow Coming Dow Coming France SA] Silicone rubber conqxl. for conq>r., transfer, or inj. molding, calendering, extrusion, and blending. 

Specimens of Class PS (gasket type materials, preformed seals) elastomers were obtained as vulcanized, post-cured sheets, approximately 0.18 cm in thickness, from their manufacturers with the exception of silicone rubbers I and J which were supplied as calendered rolls requiring a 4 h bake at 200 C before using (Table I). 

A review is presented of developments by a number of companies in rubber processing machinery, including injection moulding machines (with particular reference to presses for the processing of liquid silicone rubbers), extruders, mixers and calenders. 

Calendering is quite widely used as a technique for producing both supported and unsupported thin sheets of silicone rubber. The procedure and equipment are almost identical to that used for organic elastomers, except heated rolls are not required to ensure smooth flow and a good finish. 

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