| 摘要 |
PROBLEM TO BE SOLVED: To obtain a multi-layer flexible printed circuit board having excellent flame retardance and heat resistance, preservation stability and slight variation of insulating resin thickness between circuit layers in spite of possession of glass cloth-free insulating layer. SOLUTION: This interlayer insulating resin for a multi-layer printed circuit board comprises (1) a sulfur component-containing amorphous thermoplastic resin having 103 to 105 weight-average molecular weight, (2) a sulfur-containing epoxy resin or phenoxy resin having 103 to 105 weight-average molecular weight, (3) a polyfunctional epoxy resin having <=500 epoxy equivalent, (4) an epoxy curing agent and (5) a halogen-free phosphorus-containing compound. |
