Process for producing modified precipitated silica and composition containing modified precipitated silica

摘要

The object of the present invention is to provide an economical and yet resource-saving method for the rapid and easy production of cheap organically modified silicas, and to provide compositions having high chemical purity containing these silicas. It is to be. The first part of the object is a process for the preparation of a modified precipitated silica, wherein i) the modification comprises An acid; The reaction is carried out in a reaction mixture comprising a compound selected from precipitated silica and / or [SiO4 / 2] starting materials and an organosiliconate as a modifier, the modification reaction being to produce precipitated silica Reaction is carried out during or immediately after the reaction, ii) then the reaction mixture is filtered and washed, and iii) dried if the reaction mixture is needed, an organosiliconate is used as a modifier, an alkoxysilane or an alkali silicon silicic acid The acid salt is achieved by providing the method used as a [SiO4 / 2] starting material. The second part of the object comprises (a) at least 95% by weight of precipitated silica, (b) a carbon content of at least 0.5% by weight, and (c) a combined sodium and potassium content This is achieved by providing a composition characterized in that it is less than 5000 ppm and (d) the sulfur content is less than 2500 ppm. The compositions according to the invention can be used as antiblocking agents in toners or developers as reinforcing fillers in crosslinkable silicone rubber compounds.