| 摘要 |
PCT No. PCT/FR97/00720 Sec. 371 Date Oct. 20, 1998 Sec. 102(e) Date Oct. 20, 1998 PCT Filed Apr. 22, 1997 PCT Pub. No. WO97/40106 PCT Pub. Date Oct. 30, 1997The invention discloses a method for preparing particles comprising a dense silica shell and a core of another material, through rapid precipitation of active silica from a an aqueous alkaline metal silicate solution with pH adjustment by means of an acidifying agent, on a material support other than silica, separation of the silica slurry formed and drying of the recovered silica suspension. These composite particles consisting of a shell formed of dense silica and a non-polymer organic material core with biological, in particular phytosanitary, activity can be used for the slow release of the said solid non-polymer organic material with biological, in particular phytosanitary, activity, by slow diffusion through the silica shell. |
