COMPOSITE FILLER AND RESIN COMPOSITION

To provide a composite filler which has high conductive efficiency and can be filled with a resin while activating high thermal conductivity of aluminum nitride powder.SOLUTION: A composite filler contains, when the total of the volume of the total constituent powder is taken as 100 vol.%: 60-90 vol.% of aluminum nitride powder which is a polyhedral particle having a surface structure having at least two flat surfaces and has a cumulative 50% value (D50) in particle size distribution curve of 20-200 μm; and 10-40 vol.% of inorganic powder (B) which has thermal conductivity of 45-60 W/m K, Mohs hardness of 7 or less and a cumulative 50% value (D50) in particle size distribution curve of 2-20 μm.SELECTED DRAWING: None 【課題】窒化アルミニウム粉末の高い熱伝導性を活かしながら、伝導効率を高く樹脂充填が可能な複合フィラーを提供する。【解決手段】全構成粉末の体積の合計を１００体積％として、少なくとも２面の平坦面を有する面構造を備えた多面体粒子であり、粒度 分布曲線における累積５０％値（Ｄ50）が２０μｍ〜２００μｍの窒化アルミニウム粉末（Ａ）を６０体積％〜９０体積％と、熱伝導率が４５Ｗ／ｍ・Ｋ〜６０Ｗ／ｍ・Ｋ、モース硬度が７以下、粒度分布曲線における累積５０％値（Ｄ50）が２μｍ〜２０μｍの無機粉末（Ｂ）を１０体積％〜４０体積％とを含有することを特徴とする複合フィラー。【選択図】なし