Abstract: A thermally conductive body formed from a thermally conductive composition is provided. The thermally conductive composition includes a polymer matrix material, thermally conductive fibers, and a non-fibrous thermally conductive filler. The average fiber length of the thermally conductive fibers is in a range from 70 to 130 ?m. The thermally conductive fibers contain fine fibers having a length of 20 ?m or less in not more than 20 percent of the entire quantity of the thermally conductive fibers. The thermally conductive fibers further have diamagnetic properties. In the thermally conductive body, the thermally conductive fibers are directionally oriented. A method for manufacturing the thermally conductive body is also provided.

Abstract: A thermally conductive sheet comprising boron nitride powder as a first thermally conductive filler dispersed into an organic matrix, wherein the boron nitride powder is hexagonal boron nitride (h-BN), and comprises primary particles and secondary aggregates formed by aggregation of the primary particles, wherein at least part of the secondary aggregates being 50 &mgr;m or more in size. The boron nitride powder preferably includes 1 to 20 percent by weight of secondary aggregates of 50 &mgr;m or more in size. The organic matrix material is preferably silicone rubber.

Abstract: A heat conductive sheet comprising organic matrix and heat conductive filler contained in the organic matrix at a volume percent between 30% and 80%. The heat conductive filler comprises spherical shaped alumina grains which have an average grain diameter in a range between 50 &mgr;m and 80 &mgr;m. The heat conductive filler includes micro grains having a grain diameter of 30 &mgr;m or less at a proportion of 5 volume % or less with respect to the total amount of the spherical shaped alumina grains.

Abstract: A thermally conductive polymer composition includes polymer matrix such as thermoplastic resin or thermoplastic elastomer and a graphitized carbon fiber which serves as a thermally conductive filler. The graphitized carbon fiber is made from a mesophase pitch. The mesophase pitch is spun, infusibilized, carbonized, pulverized, and graphitized to form powdery graphitized carbon fibers. Preferably, the graphitized carbon fibers have a diameter of 5-20 &mgr;m, an average particle size of 10-500 &mgr;m, and a density of 2.20-2.26 g/cm3. The composition may be molded to form a thermally conductive molded article such as a thermally conductive sheet. The thermally conductive polymer composition and thermally conductive molded article have high thermal conductivity and transfer large amounts of heat from electric or electronic parts.

Abstract: A heat conductive sheet comprising organic matrix and heat conductive filler contained in the organic matrix at a volume percent between 30% and 80%. The heat conductive filler comprises spherical shaped alumina grains which have an average grain diameter in a range between 50 &mgr;m and 80 &mgr;m. The heat conductive filler includes micro grains having a grain diameter of 30 &mgr;m or less at a proportion of 5 volume % or less with respect to the total amount of the spherical shaped alumina grains.

Abstract: A thermally conductive sheet comprising boron nitride powder as a first thermally conductive filler dispersed into an organic matrix, wherein the boron nitride powder is hexagonal boron nitride (h-BN), and comprises primary particles and secondary aggregates formed by aggregation of the primary particles, wherein at least part of the secondary aggregates being 50 &mgr;m or more in size. The boron nitride powder preferably includes 1 to 20 percent by weight of secondary aggregates of 50 &mgr;m or more in size. The organic matrix material is preferably silicone rubber.

Abstract: A thermally conductive polymer composition includes polymer matrix such as thermoplastic resin or thermoplastic elastomer and a graphitized carbon fiber which serves as a thermally conductive filler. The graphitized carbon fiber is made from a mesophase pitch. The mesophase pitch is spun, infusibilized, carbonized, pulverized, and graphitized to form powdery graphitized carbon fibers. Preferably, the graphitized carbon fibers have a diameter of 5-20 &mgr;m, an average particle size of 10-500 &mgr;m, and a density of 2.20-2.26 g/cm3. The composition may be molded to form a thermally conductive molded article such as a thermally conductive sheet. The thermally conductive polymer composition and thermally conductive molded article have high thermal conductivity and transfer large amounts of heat from electric or electronic parts.