POLYURETHANE-BASED COMPOSITE MATERIAL, METHOD OF PRODUCING MOLDED ARTICLE MADE FROM THE POLYURETHANE-BASED COMPOSITE MATERIAL, AND DENTAL-CUTTING PROCESSING MATERIAL

To provide a polyurethane-based composite material in which fillers are dispersed in a matrix composed of a polyurethane-based resin having a content of a polyurethane component of more than 80 mass% and having a crosslinked structure, and which is uniform and excellent in strength and water resistance, and to provide a method of producing the molded article.SOLUTION: A diisocyanate (a2) is added to a first raw material composition containing a radically polymerizable diol (a1), a non-polyaddition-type radically polymerizable monomer (B), a thermal polymerization initiator (C) having a 10 hour half-life temperature: T10 of 60°C or more and a filler (D) to obtain a radically polymerizable group-containing polyurethane component (A) having a number average molecular weight of 1500 to 5000, which is a polyadduct of (a1) and (a2). A second raw material composition containing the radically polymerizable group-containing polyurethane component (A) content ratio of which is more than 80 mass% in the organic component is prepared and is filled in a mold in a state where the composition is maintained at a temperature of 40 to (T10-15)°C, and is subsequently cured by radical polymerization at (T10-10) to (T10+25)°C.SELECTED DRAWING: None 【課題】 ポリウレタン成分の含有率が８０質量％を超え且つ架橋構造を有するポリウレタン系樹脂からなるマトリックス中に充填材が分散してなり、均一で強度及び耐水性に優れるポリウレタン系複合材料及びその成形体の製造方法を提供する。【解決手段】 ラジカル重合性ジオール（ａ１）、非重付加性ラジカル重合性単量体（Ｂ）、１０時間半減期温度：Ｔ１０が６０℃以上である熱重合開始剤（Ｃ）、充填材（Ｄ）を含む第１原料組成物にジイソシアネート（ａ２）を加えて、（ａ１）と（ａ２）の重付加物である、数平均分子量：１５００～５０００のラジカル重合性基含有ポリウレタン成分（Ａ）を含み、且つ有機成分中に占める（Ａ）の含有率が８０質量％を超える第２原料組成物を調製し、これを４０～（Ｔ１０－１５）℃の温度に保持した状態で、モールド内に充填した後に、（Ｔ１０－１０）～（Ｔ１０＋２５）℃でラジカル重合を行って硬化させる。【選択図】なし