Preparation method of large-particle-size ASA latex

The invention discloses a preparation method of large-particle-size ASA latex, and belongs to the technical field of ASA latex preparation. The preparation method comprises the following steps: firstly, stirring deionized water, an acrylate monomer, an emulsifier, a cross-linking agent and an initiator until the components are completely dissolved, and then heating to 55-75 DEG C in the presence of nitrogen to react for 0.5-2 hours; adding an acrylate monomer, an emulsifier, a cross-linking agent and an initiator to obtain polyacrylate latex; then adding deionized water, a chelating agent, a reducing agent, an assistant reducing agent and an initiator, and heating to 50-75 DEG C in a nitrogen environment; dropwise adding a styrene monomer, an acrylonitrile monomer and an initiator, heating to 75 DEG C, and preserving heat for 1-2 hours to obtain the large-particle-size ASA latex. According to the invention, the existing PBA emulsion synthesis process and ASA emulsion synthesis process are improved, the prepar