PROPPING FILLER Russian patent published in 2019 - IPC C09K8/80 E21B43/267 

FIELD: chemistry.

SUBSTANCE: invention relates to propping filler used in hydraulic fracturing of underground formation. Propping filler for hydraulic fracturing of underground formation, containing particle, which is in amount of 90 to 99.5 wt % in terms of total weight of said filler, and polyurethane coating on said particle and in amount of 0.5 to 10 wt% in terms of total weight of said filler, wherein the polyurethane coating contains a reaction product of an isocyanate component and an isocyanate-reactive component containing a polydiene polyol and a chain extender with hydroxy functionality greater than 1.5 and not more than 4. Method of producing said filler, comprising combining an isocyanate component and an isocyanate-reactive component containing a polydiene polyol, and a chain extender with hydroxy functionality of more than 1.5 and not more than 4 to obtain a reaction mixture and coating the reaction mixture on the particle to obtain a propping agent containing a particle and a polyurethane coating on it. Invention is developed in dependent items of the formula.

EFFECT: higher quality of propping agent.

21 cl, 10 ex, 3 tbl