Method for preparing a silica suspension in a vulcanisable silicon matrix to form elastomers

Process for preparing a suspension of a particulate, preferably siliceous, filler in a material formed by a silicone oil comprising:

• polyorganosiloxanes (POS fluids) of type (I) which carry Si-alkenyl—preferably Si-vinyl—functional groups capable of reacting with the Si-H crosslinking functional groups of a POS fluid of type II,
• optionally, POS fluids of type (II) which carry Si-H crosslinking functional groups capable of reacting with the Si-alkenyl functional groups of the POS fluids (I),
• and/or, optionally, POS fluids of type (III) which differ from the POS fluids (I) and (II),
• the said suspension being able to be used, in particular, for producing silicone compositions that can be cured by polyaddition, this process being of the kind of those in which the particulate filler is treated with the aid of a compatibilizing agent or compatibilizer (CA),
• characterized in that it essentially consists in introducing some compatibilizer (CA) into the preparation mixture:
• on the one hand, before and/or substantially simultaneously with the contacting of at least part of the silicone oil employed with at least part of the particulate filler used, this CA introduction taking place in one or more steps for a CA fraction corresponding to a proportion of at most 8%, preferably at most 5% and even more preferably at most 3% by dry weight with respect to the total particulate filler;
• and, on the other hand, after this POS/filler contacting.