add 750 kg of distilled water into the reaction kettle, add 15 kg of flat o under stirring, and heat to dissolve. Then 130 kg of propylene butyl ester, 35 kg of acrylonitrile and 5 kg of 10% ammonium persulfate aqueous solution were added. React at 70~80 ℃ for 2 h. Transfer it to an emulsifying kettle, and add an appropriate amount of molecular chain control agent carbon tetrachloride under high-speed stirring to protect colloidal gum arabic and polyvinyl alcohol. Finally, add emulsifying thickener fire oil, fully emulsified to obtain the finished product.