The invention relates to a cation cross-linked
styrene-acrylic surface
sizing agent and a preparation method thereof. The surface
sizing agent comprises the following raw materials: 10-15 parts of dispersing agents, 0.5-1 parts of oxidizing agents, 1-3 parts of initiating agents, 10-20 parts of hard monomers, 10-15 parts of soft monomers, 1-10 parts of functional monomers, 1-10 parts of cationic monomers, 3-10 parts of crosslinking monomers and 50-80 parts of deionized water, wherein the hard
monomer is one or combination of more than one of the
styrene,
vinyl acetate and
methyl methacrylate, and the dispersing agent is native
starch. The surface
sizing agent utilizes the native
starch as the dispersing agents to synthesize the
styrene-acrylic surface sizing agent together with raw materials; and compared with a conventional
starch-synthesized styrene-acrylic surface sizing agent, the surface sizing agent in the invention is better in film-forming property, higher in stability and higher in
cost performance; and the surface sizing agent allows paper to have better
water resistance, and meanwhile, can greatly reduce paper sizing cost.