TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The surface of spherical metal oxide microparticles (B) contains metal oxide microparticles processed by silane coupling agent and/or silazane such as hexamethyldisilazane. The silane coupling agent is a compound(s) having active group chosen from amino, glycidyl, mercapto, ureido, hydroxyl, alkoxy and mercapto. The spherical metal oxide microparticles (B) contain 60-100 mass% of spherical-shaped silica having average particle diameter of 0.05-10 mu m. The organic solvent (C) has boiling point of 200 degrees C or more. The content of organic solvent (C) in the resin composition is 10-500 mass parts with respect to 100 mass parts of partial block polyimide polysiloxane copolymer (A).    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The resin composition contains partial block polyimide polysiloxane copolymer (A) having repeating unit of formulae (2 and 8) and optionally having repeating unit (1), spherical metal oxide microparticles (B) having average particle diameter of 0.05-10 mu m, organic solvent (C), epoxy resin (D) having 2 epoxy groups or more in one molecule, and hardening agent (E) which provides hardening effective dose for epoxy resin (D).Y3=divalent organic group with functional group having reactivity with epoxy;andj=1-50.The molar ratio of Y2 with respect to sum of Y1, Y2 and Y3 is 0.01-0.8. The molar ratio of Y3 with respect to sum of Y1, Y2 and Y3 is 0.01-0.99. EXAMPLE - 3,3',4,4'-Benzophenone tetracarboxylic-acid dianhydride (in mass parts) (45.11) and cyclohexanone (445) were added, stirred at 50 degrees C, acid dianhydride was dispersed, KF-8010 (RTM: diamino siloxane) was added, stir-reacted at room temperature for 12 hours, toluene (40 ml) was added into the obtained polyamic-acid oligomer solution, heat-dehydrated at 160 degrees C for 8 hours, and water (4.3 ml) was distilled-off, to obtain polyimide oligomer solution (A) having acid anhydride terminal. Aromatic diamine (59.36) having phenolic hydroxyl group and cyclohexanone (311 mass parts) were added into a reactor, stir-dissolved at 50 degrees C, 2,2-bis(3,4-benzenedicarboxylate anhydride)perfluoro propane (44.42) was added, stir-reacted at room temperature for 12 hours, toluene (40 ml) was added, heat-dehydrated at 160 degrees C for 8 hours, and water (3.6 ml) was distilled-off, to obtain polyimide oligomer solution (B) having amino group terminal. The polyimide oligomer solution (A) having acid anhydride terminal and polyimide oligomer solution (B) having amino group terminal were added, stir-reacted at 50 degrees C for 6 hours, toluene (20 ml) was added, heat-dehydrated at 160 degrees C for 8 hours, water (0.7 ml) was distilled-off, to obtain polyimide siloxane fluid containing partial block polyimide polysiloxane copolymer. Partial block polyimide polysiloxane copolymer (50), N-methyl-2-pyrrolidone (100), 1,3-dimethyl-2-imidazolidinone (25), EOCN1020 (RTM: ortho-cresol novolak-type epoxy resin) (35.64), TD2131 (RTM: phenol novolak-type resin) (12.43), triphenylphosphine (0.5), SC2500-SE (RTM: spherical-shaped silica particle) (20) having average particle diameter of 0.5 mu m, and AEROSIL R972 (RTM: fumed silica) (2) were uniformly mixed, to obtain paste-form resin composition.