| 摘要 |
PURPOSE:To obtain a polyimide prepreg for laminating use which gives a highly reliable laminate by continuously impregnating a substrate with a polyimide resin varnish containing a specific solvent and continuously drying it to thereby attain uniform impregnation. CONSTITUTION:A polyimide resin varnish is produced using as a solvent a dipropylene glycol monoalkyl ether represented by the formula (wherein R is methyl or ethyl) (e.g. diprogylene glycol monomethyl ether). A substrate (e.g. glass cloth) is continuously impregnated with this varnish and continuously dried to thereby produce a polyimide prepreg for laminating. The varnish has good stability due to the application of the specific solvent. By use of the pregreg, a copper-clad laminate free from voids or skips can be produced. |
