Composite film

The invention provides an insulating material which is excellent in aging resistance, good in insulativity, good in rigidity, simple in processing method and low in cost, the insulating material is provided with one or more polymer film layers and one or more adhesive layers, after the composite film is subjected to oil aging tests for four times, the breaking strength retention rate is larger than 50%, the retention rate of elongation at break is more than 53%, the peel strength is more than 1N/cm, at least one of the polymer film layers is a polyphenylene sulfide film layer, and the composite film contains an aramid paper layer. 本发明提供一种耐老化性优异、绝缘性佳、刚性好、加工方法简单、成本低廉的绝缘材料，设有一层或一层以上的聚合物薄膜层和一层或一层以上的胶黏剂层，所述的复合薄膜经循环4次的油老化性试验后，断裂强度保持率大于50％，断裂伸长率保持率为53％以上，且剥离强度大于1N/cm，所述的聚合物薄膜层的至少一层是聚苯硫醚薄膜层，所述的复合薄膜含有芳纶纸层。