▎ 摘　　要

NOVELTY - Surface sizing agent comprises 5-10 wt.% cationic microcrystalline cellulose, 5-10 wt.% cationic rosin gum, 5-10 wt.% cationic peach gum, 1-3 wt.% polydimethyl silicone oil, 14-22 wt.% silicone modified styrene-acrylic emulsion, 45-70 wt.% nano graphene modified fluorine-containing polyacrylate emulsion, where the cationic microcrystalline cellulose/rosin gum/peach gum is prepared by etherification modification of microcrystalline cellulose/rosin gum/peach gum with cationic etherifying agent. The nano graphene-modified fluorine-containing polyacrylate emulsion is obtained by copolymerizing and crosslinking methacrylic acid monomer, fluorine-containing acrylic monomer and hydroxylated graphene. USE - Surface sizing agent. ADVANTAGE - The surface sizing agent has small dosage, fast curing, strong film forming ability, good sizing effect and low cost, and the sizing paper has high epoxy strength and excellent durability, and can be waterproof, anti-fouling and self-cleaning. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing surface sizing agent, which involves: (A) grinding microcrystalline cellulose/rosin/peach gum to 100-200 mesh, dispersing in 30-40% potassium hydroxide solution, alkalizing, then, adding cationic etherification agent, and stirring the reaction at 65-70 degrees C for 2 hours, neutralizing, filtering, and drying to obtain cationic microcrystalline cellulose/rosin gum/peach gum; (B) mixing graphene, potassium hydroxide and potassium peroxide, ball milling for 1 hour, adding the contents to 5-10% ethylene glycol solution, stirring for 0.5-1 hour at -45 degrees C nitrogen atmosphere, freezing for 6-10 hours, then thawing in nitrogen atmosphere at 15 degrees C for 8-12 hours, and repeatedly freezing and thawing three times to shape the hydroxylated graphene, adjusting the pH to 7.2-7.4 to obtain the hydroxylated graphene solution; (C) dispersing 10-15 pts. wt. methacrylic acid, 20-30 pts. wt. fluorine-containing acrylic acid monomer, 15-20 pts. wt. hydroxylated graphene solution, 1-3 pts. wt. polyoxyethylene fatty alcohol ether in 100 pts. wt. deionized water, adding 0.1-0.5 pts. wt. azobisisobutyronitrile, 0.5-1 pts. wt. nano-zirconia and 0.1-0.3 pts. wt. boric acid, performing polycondensation reaction at 85 degrees C for 1-3 hours to obtain the nano graphene modified fluorine-containing polyacrylate emulsion; and (D) mixing cationic microcrystalline cellulose, cationic rosin gum, cationic peach gum, polydimethyl silicone oil, silicone modified styrene-acrylic emulsion and nano graphene modified fluoropolyacrylate, and ultrasonically dispersing the emulsion to obtain the required product.