▎ 摘　　要

NOVELTY - Polyvinylidene chloride copolymer emulsion comprises 20-40 pts. wt. deionized water, 40-60 pts. wt. vinylidene chloride monomer, 3-7 pts. wt. acrylic monomer, 6-10 pts. wt. methyl methacrylate monomer, 3-5 pts. wt. acrylonitrile monomer, 0.25-0.7 pts. wt. initiator and 3-6 pts. wt. emulsifier. USE - The film-forming composition is useful in preparing for aqueous-based anticorrosive coatings (claimed). ADVANTAGE - The polyvinylidene chloride copolymer emulsion: ensures safety; is environmental friendly; and has excellent protection performance and salt spray resistance. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) preparing polyvinylidene chloride copolymer emulsion comprising (a) preparing seed emulsion by mixing 62.5-75 wt.% deionized water, 60-75 wt.% initiator, 55-70 wt.% vinylidene chloride monomer, 50-70 wt.% acrylic monomer and 25-40 wt.% emulsifier, heating to 70-85degrees Celsius to react for 10-30 minutes for obtaining seed emulsion, (b) preparing mixed emulsion by mixing remaining amount of deionized water, remaining amount of initiator, and emulsifier to obtain mixed emulsion, (c) preparing mixed monomers by mixing all acrylonitrile monomers, all methyl methacrylate monomers and remaining vinylidene chloride monomers and the remaining acrylic monomers to obtain mixed monomers, (d) preparing polyvinylidene chloride copolymer emulsion by reacting above seed emulsion, mixed emulsion and mixed monomer at 55-70degrees Celsius at a speed of 80-120 revolutions/minute for 1.5-2.5 hours, heating to 80-90degrees Celsius and performing reaction for 1.5-2.5 hours; and (2) film-forming composition comprising 100-120 pts. wt. polyvinylidene chloride copolymer emulsion and 5-20 pts. wt. stabilizer.