▎ 摘　　要

NOVELTY - Preparing halogen-free synergistic flame retardant comprises (i) adding graphene oxide in solvent one, and ultrasonically dispersing for 30-60 minutes to obtain 5-8 wt.% dispersion A, (ii) adding 2-(diphenylphosphino)ethyltriethoxysilane and dibutyltin dilaurate in solvent two, and ultrasonically treating for 30 minutes to obtain dispersion B, (iii) mixing dispersion A and dispersion B, and mechanically stirring for 1-2 hours to obtain mixed solution, and (iv) dissolving phosphatized chitosan in deionized water, stirring, dissolving for 20-30 minutes to 0.5-3 wt.% concentration, slowly adding mixed solution dropwise under nitrogen protection, raising temperature to 50-70 degrees C, reacting for 6-8 hours, centrifuging, washing with deionized water and absolute ethanol, and lyophilizing to obtain halogen-free synergistic flame retardant. USE - The halogen-free synergistic flame retardant is useful in ink (claimed). ADVANTAGE - The halogen-free synergistic flame retardant good stability; and is environmentally friendly. The ink reaches UL-94 combustion test to V-0 level. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) halogen-free synergistic flame retardant; (2) use of halogen-free synergistic flame retardant in ink; (3) ink comprising 35-50 pts. wt. aqueous emulsion, 4-8 pts. wt. pigment, 3-5 pts. wt. halogen-free flame retardant, 0.5-1 pts. wt. antifoaming agent, 0.5-2 pts. wt. dispersant, and 15-30 pts. wt. de-ionized water; and (4) preparing ink comprising adding pigment and halogen-free synergistic flame retardant in aqueous emulsion, stirring, grinding at high speed with grinding equipment, adding deionized water, antifoaming agent, and dispersant, mechanically stirring, and filtering by 100-300 meshes screen to obtain ink.