Free radical polymerization-based preparation method of water-based coating

The invention discloses a free radical polymerization-based preparation method of a water-based coating. The preparation method comprises the following steps: (1) obtaining liquid illegal cooking oilby adopting a solid-liquid separation technology, then washing the liquid illegal cooking oil respectively with deionized water and a strong-polarity organic solvent in which the illegal cooking oil cannot be dissolved, and finally adding a decoloring agent till the illegal cooking oil is faint yellow, transparent and clear liquid, thus obtaining purified illegal cooking oil; and (2) adding the deionized water, a pH modifier, an emulsifier, a dispersant, an initiator, the purified illegal cooking oil and acrylic ester into a reaction kettle in sequence according to a weight ratio of 90:(0.15-0.23):(1.6-2.2):(0.1-0.5):(0.5-1.5):(43-54):(40-60), and stirring for 10 to 14 min at a stirring speed of 300-800 r / min, thus obtaining illegal cooking oil emulsion. According to the free radical polymerization-based preparation method disclosed by the invention, instable unsaturated oil with low molecular weight is subjected to free radical polymerization to form stable copolymer resin water emulsion with high polymerization degree, so that the prepared water-based coating is high in film forming property and adhesive force and can be widely applied to the field of decoration of a building external wall and the like.