PROBLEM TO BE SOLVED: To provide a sustained-release material which can be impregnated with a volatile compound by a supercritical impregnation method using a supercritical fluid, and which can contain a large amount of the volatile compound and is excellent in sustained-release performance. Of functional materials. A sustained-release material containing a vinyl alcohol-based resin (A) and a thermoplastic resin (B) for gradually releasing an impregnated volatile compound (C), which is a thermoplastic resin (B). ), the SP value is 7 to 12, and the content ratio (weight ratio) of the vinyl alcohol resin (A) and the thermoplastic resin (B) is 95/5 to 55/45. [Selection diagram] None【課題】超臨界流体を用いた超臨界含浸法により揮発性化合物を含浸させることができる徐放性材料であって、揮発性化合物を多く含有させることができ、徐放性能に優れた徐放性材料の提供。【解決手段】ビニルアルコール系樹脂（Ａ）および熱可塑性樹脂（Ｂ）を含有し、含浸された揮発性化合物（Ｃ）を徐放するための徐放性材料であって、熱可塑性樹脂（Ｂ）のＳＰ値が７～１２であり、ビニルアルコール系樹脂（Ａ）と熱可塑性樹脂（Ｂ）の含有割合（重量比）が９５／５～５５／４５である徐放性材料。【選択図】なし
