| 摘要 |
PURPOSE:To obtain an epoxy resin film excellent in electrical properties, heat resistance, humidity resistance, chemical resistance, etc., by molding a linear high molecular weight epoxy resin by a solvent exchange process. CONSTITUTION:A solution of a high molecular weight epoxy resin (of an average molecular weight in terms of polystyrene as determined by GPC of 50000 or above, desirably 100000 or above), for example, a 20% N,N-dimethylacetamide solution is applied to the surface of a roller-like object, and this object is immersed in a solvent other than the one used in the polymerization, e.g. hot water to effect solvent exchange to thereby mold a film (of a thickness of 100mum or below). The high molecular weight epoxy resin is prepared by polymerizing a diepoxy resin with a bisphenol in an epoxy to phenolic hydroxyl ratio of 1:(0.9-1.1) in the presence of a catalyst in a reaction solvent. |
