| 摘要 |
PROBLEM TO BE SOLVED: To provide a pumping impeller that is excellent in hygroscopic resistance (a dimensional change due to moisture absorption is little), and large enough in the mechanical strength of a thin-wall part. SOLUTION: This impeller is amde up of molding a resin composition having mixed phenol aralkyl resin and a filler to phenol resin. This phenol aralkyl resin acts to control moisture absorption. A main filler is composed of glass chops 20 to 80wt.% of 3mm in fiber length in substance and of glass chops 80 to 20wt.% of 150um in fiber length in substance. Both characteristics of fillability improvements by a short glass fiber and strength improvements by a log glass fiber are well maintainable, and good in hygroscopic resistance and, further there is no strength drop in a thin-wall part (an impeller blade part). A fact that the fiber length is 3mm in substance means 2 to 4mm in fiber length and that 150μm in substance means 100 to 200μm in fiber length, respectively.
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