The invention relates to a toughened modified
vinyl ester resin and a synthesis method thereof. The method comprises the following steps: (1) adding diisocyanate and flexible dihydric
alcohol into a reaction kettle, adding a catalyst A, and taking the point at which the content of
isocyanate reaches 1-9% as a reaction endpoint so as to prepare an
isocyanate-terminated
polyurethane prepolymer; (2)adding 35-49% of
epoxy resin, 10-20% of unsaturated monocarboxylic acid, 0.1-1.0% of a catalyst B and 0.01-0.1% of a
polymerization inhibitor into another reaction kettle, and performing a reaction until the
acid value is reduced to 12 mgKOH / g or below; and (3) lowering the temperature, adding 5-20% of the
polyurethane prepolymer and 0.05-0.2% of the catalyst A performing a reaction until the content of
isocyanate groups is zero to reach a reaction endpoint, and finally adding 30-40% of a cross-linking agent to obtain the
polyurethane toughened and modified
vinyl ester resin. Compared with theprior art, the preparation method has the advantages of completeness in chain extension reaction, good
toughening effect, few side reactions, safety,
environmental protection and stable quality through optimizing the molecular structure by reacting the isocyanate-terminated polyurethane
prepolymer with the
vinyl ester resin and introducing a flexible group is introduced into the molecular chain.