THERMOSETTING RESIN COMPOSITION AND ITS CURED ITEM

摘要

PROBLEM TO BE SOLVED: To obtain a thermosetting resin compsn. improved in curability, mechanical characteristics, and flame retardance by compounding a thermosetting resin having dihydrobenzoxazine rings with a novolak phenol resin. SOLUTION: A compd. having at least two hydroxyphenylene groups each having at least one o-position with an II atom bonded thereto, a prim. amine in an amt. of 0.5-1.0mol based on 1mol of phenolic hydroxyl group of the foregoing compd., and formaldehyde in an amt. of at least 2mol based on 1mol of the amine are reacted at 70-110 deg.C for 20min to 2hr and dried under vacuum at 120 deg.C or lower to give a thermosetting resin having dihydrobenzoxazine rings. 60-97wt.% above-obtd. resin is compounded with 3-40wt.% novolak phenol resin having an ortho ratio of 50% or higher.