| 摘要 |
PROBLEM TO BE SOLVED: To effectively exhibit high insulating capability of a polyimide resin film even under an extremely low temperature condition by adding an inorganic base material and a polyimide resin film through an expoxy resin composition mixing a high polymer having specific number average molecular weight and weight. SOLUTION: A glass cloth prepreg is formed by using an expoxy resin adding polyvinyl formal as a high polymer, to impregnated a glass cloth as insulating materials 4a and 4b for an extremely low temperature arranged in a superconducting material 1, and a polyimide resin film is stuck to these glass cloth prpgregs, and a prepreg-shaped insulating material for an extremely low temperature is formed. In this case, it is formed by sticking the polyimide resin film to the glass cloth prepreg by using an epoxy resin composition mixing the high polymer having number avergage molecular weight not less than 10000 by 5%, (weight) or more into the glass cloth. A phenoxy resin and carboxylation NBR rubber or the like are cited as the high polymer. |
