Double-end cyano-group active ester, thermosetting resin composition, and preparation method and application of double-end cyano-group active ester and thermosetting resin composition

The invention provides double-end cyano active ester, a thermosetting resin composition as well as a preparation method and application of the double-end cyano active ester and the thermosetting resin composition. The double-end cyano active ester has a structure as shown in a formula I. The double-end cyano active ester has a structure as shown in a formula I; the epoxy resin has high reaction crosslinking sites, low dielectric loss, low dielectric constant and low water absorption rate, and can be used as a curing agent to be subjected to curing reaction with epoxy resin, and the obtained cured product has excellent dielectric property, heat resistance, humidity and heat resistance and low thermal expansion coefficient. The thermosetting resin composition containing the double-end cyano active ester has high Tg, excellent heat resistance, mechanical property and adhesive property, and good dielectric property and processability, and can be widely applied to semiconductor sealing materials, prepregs, circuit