put 225 kg of distilled water into the reaction kettle, add 45 kg of flat O and appropriate amount of polyvinyl alcohol, heat and dissolve under stirring, then add 33 kg of butyl acrylate, 15 kg of acrylonitrile and 5kg(10%) of ammonium persulfate aqueous solution, and raise the temperature to 80 ℃ for polymerization. After reaction for 0.5 h, 67 kg butyl acrylate, 35 kg acrylonitrile and 4.0kg(10%) ammonium persulfate aqueous solution were gradually added and reacted at 80~85 ℃ for 2 h. Transfer it to the emulsification kettle, add an appropriate amount of fire oil under rapid stirring, and add an appropriate amount of gum arabic and carbon tetrachloride after emulsification. Cooling the discharge is the finished product.