METHOD FOR PREPARING HYDROPHOBIC DISPERSED MATERIAL Russian patent published in 2004 - IPC

FIELD: physical chemistry.

SUBSTANCE: invention relates to methods for chemical modification of surfaces of highly dispersed material to confer them selective, protective and apyrogenic effect. Method for preparing hydrophobic dispersed material based on silicon dioxide, filling agent and additive involves chemical modification of mixture with organosilicon compound in the process of mechanical stirring at increased temperature. Methylhydride siloxane or mixture of methylhydride siloxane with aminoethylaminopropyltrimethoxysiloxane or amino-functional siloxane as a hardening catalyst is used as a modifying agent. Modifying agent is used as 10-70% solution in chloroorganic solvent in the amount 0.2-0.6% of powdered mixture as measured for dry residue. Feeding a modifying agent into mixer is carried out in consumption 20-100 g/s at the rate of mixer rotor revolution 20-45 rev./min at temperature in mixer 70-130 R, or in simultaneous charging with powder-like components. Mixing components is carried out with their simultaneous grinding and drying to humidity 0.35 wt.-%, not above, and specific surface 3000 cm²/g, not less, in the ratio of mass of milling bodies to the total mass of dispersed material from 1:0.6 to 1:1.5. The complex nitrogen-phosphorus and/or phosphorus-potassium, and/or nitrogen-phosphorus-potassium fertilizer is used as a filling agent; Mineral or mixture of minerals with density 2.8 g/cm³, not less, and particles size 200 mcm, not above, is used as additive in the ratio filling agent : silicon dioxide : special additive = (36.73-62.3):(1-10):(3.3-20), respectively. Invention provides simplifying and intensifying the process in reducing labor consumptions and material resources.

EFFECT: improved preparing method.

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