| production method | polyvinyl alcohol (PVA) aqueous solution is filtered by microporous filter membrane processing, insoluble substances are removed, placed in a reaction bottle, added with appropriate amount of acrylic acid and potassium persulfate, heated to 60 ℃ for graft crosslinking polymerization for 2 hours under stirring, cooled to room temperature, neutralized with NaOH aqueous solution, then expanded with water to 98%-98.5% of water content, and packed in ampoules, after nitrogen replacement, it will be melted and sealed and sterilized at 120 ℃. |