Size and preparation method thereof coated on fiberglass surfacing

The invention discloses the sizes and preparation method thereof for being coated on fiberglass surfacing, the composition and weight percent of size therein coated on fiberglass surfacing are respectively as follows: glacial acetic acid accounts for size gross mass 0.05~0.1%, coupling agent A accounts for the 0.25-0.6% of size gross mass, coupling agent B accounts for the 0.48-0.9% of size gross mass, phase solvent accounts for the 0.25-0.55% of size gross mass, lubricant accounts for the 0.22-0.42% of size gross mass, wax emulsion accounts for the 4.0-7.5% of size gross mass, brightener accounts for the 0.4-0.8% of size gross mass, surplus is water.