PHENOL RESIN, CURABLE RESIN COMPOSITION AND CURED PRODUCT THEREOF

PROBLEM TO BE SOLVED: To provide a phenol resin which has an excellent balance between a mold shrinkage factor and an elastic modulus during heat curing of a composition and gives a cured product having good flame retardancy; a composition; and a cured product thereof.SOLUTION: There are provided: a phenol resin represented by the formula (1) in which the total of the introduction rate of a t-butyl group or a t-octyl group is 10 to 95%; a composition; and a cured product thereof. (Reach independently is H, an alkyl group having 1 to 8 carbon atoms, at least one of which represents a t-butyl group or a t-octyl group; p is an integer of 1 to 3; q is an integer of 1 to 4; m is 0 or 1; n is a repeating number of 1 to 10 on average; Rmay be the same or different for each repetition.)SELECTED DRAWING: None 【課題】組成物の加熱硬化時の成形収縮率、弾性率のバランスに優れ、得られる硬化物の難燃性も良好となるフェノール樹脂、組成物、およびその硬化物を提供すること。【解決手段】式（１）で表されるフェノール樹脂であって、ｔ−ブチル基又はｔ−オクチル基の導入率の合計が１０〜９５％とするフェノール樹脂、組成物、及びその硬化物。（Ｒ１は夫々独立してＨ又はＣ１〜８のアルキル基、少なくとも１つはｔ−ブチル基又はｔ−オクチル基；ｐは１〜３の整数；ｑは１〜４の整数；ｍは０又は１；ｎは繰り返し数で平均値で１〜１０；繰り返し毎にＲ１は同一でも異なっていてもよい）【選択図】なし