▎ 摘　　要

NOVELTY - Preparing modified resin comprises reacting hydroxy-containing resin and graphene oxide with diisocyanate in the presence of organic tin catalyst at 40-85degrees Celsius, preferably 55-65degrees Celsius. USE - The method for preparing modified resin is useful for sizing agent as carbon fiber sizing agent (claimed). ADVANTAGE - The method uses graphene oxide and the hydroxy-containing resin, which are connected by diisocyanate, which improves the compatibility between the anti-wear agent graphene oxide and the hydroxy-containing resin and the stability of the sizing agent, and significantly improves abrasion resistance of the carbon fiber treated with the sizing agent. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: modified resin prepared by the above-mentioned method; and izing agent, comprising component A: modified resin, component B: emulsifying agent, component C: water; and optionally, component D: additive.