| 摘要 |
PROBLEM TO BE SOLVED: To provide a thermosetting resin molding material having 250 V tracking resistance and excellent in wearability in sliding and burring resistance without deteriorating the mechanical strengths, insulating properties, moldability and the like, inherent in a phenol resin. SOLUTION: The molding material contains (a) a phenol resin and (b) magnesium hydroxide respectively in amounts of 10-30 wt.% and 30-70 wt.% based on the whole molding material, and it also contains (c) a polyvinyl butyral resin having a degree of polymerization of 250 to 2,500 and a degree of butyralization of 60 to 80 mol% in an amount of 30-150 pts.wt. based on 100 pts.wt. of the phenol resin.
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