Process for preparing polydiorganosiloxanes with silanol endgroups.

摘要

The present invention relates to a process for the preparation of a polydiorganosiloxane with silanol ends.
<??>According to the process of the invention a polydiorganosiloxane oil with silanol ends, of viscosity of 10 to 4,000 mPa s is polycondensed in bulk at a temperature of 70-200 DEG C in the presence of perfluoromethanesulphonic acid with removal of the water formed. The polycondensation is stopped instantaneously by addition of a polysilazane chosen from cyclopolydiorganosilazanes and polydiorganosilazanes with diorganoaminosilyl ends.
<??>The process according to the invention makes it possible to obtain polydiorganosiloxane oils or resins with silanol ends capable of being employed especially for the manufacture of silicone compositions capable of being vulcanised to elastomers.