| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an insulation wire which lowers dielectric constant thereof by providing an insulation layer mainly formed of polyester imide, and to provide a polyester imide resin based varnish which can form an insulation film with low dielectric constant. <P>SOLUTION: A dielectric constant of the polyester imide based insulation film is correlated to the weight molecular weight of polyester imide before being heated and cured. Accordingly, polyester imide which is obtained by reacting an anhydride of a multivalent carboxylic acid, a dicarboxylic acid and/or an alkyl ester thereof (hereinafter, collectively referred to as "carboxylic acids"), alcohols and a diamine compound, and has a weight average molecular weight (Mw) of 9,000 or more, is used for the varnish as a main component. <P>COPYRIGHT: (C)2012,JPO&INPIT |
