Preparation method of low-density water-soluble normal-temperature temporary plugging agent for coal mine hydraulic fracturing

The invention belongs to the technical field of mine hydraulic fracturing, and particularly relates to a preparation method of a low-density water-soluble normal-temperature temporary plugging agent for coal mine hydraulic fracturing. The method comprises the following steps: dropwise adding distilled water into acrylic acid to obtain an acrylic acid solution; preparing a sodium hydroxide solution under the condition of ice-water bath; adding the sodium hydroxide solution into the acrylic acid solution; then adding acrylamide powder and sodium persulfate powder, and stirring until no solid particulate matter exists in the aqueous solution to obtain a component A; adding polyvinyl alcohol into the component A in a stirring state until no precipitate is generated; waiting for flocculent particles to precipitate and layer, removing supernatant, and sucking and squeezing lower colloidal precipitate into a container filled with a paraffin solution by the solution; and heating in a water bath, drying, crushing and