| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sealing material which does not cause electric failure caused by carbon black and is excellent in moldability, reliability and laser- markability by blending carbon black as a masterbatch whose matrix is an epoxy resin or a curing agent. SOLUTION: A phenol novolak epoxy resin or the like is used although any types of epoxy resins can be used. As a curing agent, a phenol resin type curing agent such as a phenol aralkyl resin and the like is used. The content of the curing agent is 0.7-1.3 in terms of the ratio of the number of epoxy groups in the epoxy resin/the number of hydroxy groups in the curing agent. Preferably carbon black has a particle size of the primary particles of 10-100 nm. A masterbatch is prepared by blending predetermined amounts of a curing agent and carbon black, kneading it with a kneader or the like and cooling it. The obtained mixture is kneaded again with a heat roll, cooled and crushed. Preferably the carbon black content is 0.3-60 wt.%. |
