METHOD OF OBTAINING SILICA THREAD Russian patent published in 2018 - IPC C03C25/66 

FIELD: manufacturing technology.

SUBSTANCE: invention relates to process for preparation of silica thread. Glass filament is wound on perforated mandrel and vertically placed in working chamber. Through lower end of stationary mandrel under pressure generated by circulation pump, at rate of 0.5–3.0 l/kg, working agents are passed that pass through thread layer, treating it, and are continuously withdrawn from working chamber by gravity into storage container. Perforation on mandrel is staggered in area from 10 % to 50 % of total area of outer surface. Initially, filament is treated with cooled solution of sulfuric acid with temperature of no more than 20 °C and concentration of 10 to 50 % by weight, and subsequent hot treatment with sulfuric acid is carried out in 2 stages with intermediate washing of filament between stages of filtered water. In first step, solution with concentration of 10 to 20% by weight, with temperature of 70 °C to 90 °C for 10 to 30 minutes, and in second stage – solution with concentration of 3 to 10 % by weight, with temperature of 90 °C to 98 °C for 30 to 80 minutes.

EFFECT: technical result is increase in breaking load.

1 cl, 1 dwg, 2 tbl