Method for the continuous preparation of master batches for heat-vulcanizable silicone elastomer

Abstract

Abstract 1. Process for continuous preparation of master-batches, in the form of thick and homogeneous doughs, to obtain subsequently silicone elastomers capable of being vulcanized when heated, characterized : - in that an endless twin-screw mixer (1) is fed continuously with at least -a) a polysiloxane resin containing from 0 to 4% by weight of vinyl group and whose viscosity at 25 degrees C is higher than 1,000,000 mPa s, and -b) a powdery filler whose specific surface area is greater than 20 m**2 /g, the filler/resin weight ratio being between 5/100 and 100/100, preferably between 10/100 and 70/100, - in that the volatile products are degassed in the course of their progress in the mixer (1), - in that the screws rotate at a circumferential velocity of between 2 cm/s and 5 m/s, preferably between 50 cm/s and 3 m/s, - in that the masterbatch is entrained by the screws at the end (10) of the mixer (1) away from that (9) towards which the products have been introduced, - in that the masterbatch flows continuously from the twin-screw mixer (1) into an apparatus (2) where it is pressurized, and - in that the masterbatch flows continuously through a filter (3) as it leaves the apparatus (2).

Inventors

• 👤 Maurice Alliot-Lugaz
• 👤 Gilbert Roullet

Bibliographic Details