| 摘要 |
PROBLEM TO BE SOLVED: To provide flame retardancy without adding halogen by adding a phosphorus compound expressed by a specific chemical formula at a weight ratio within a specific range, adding multifunctional epoxy resin containing a specific number or more of glycidyl groups, and adding biphenyl epoxy resin with a weight-average molecular weight within a specific range. SOLUTION: A phosphorus content of 1.5-10 wt.% of a phosphorus compound expressed by the formula is mixed with resin solid contents composing an interlayer insulating adhesive (in the formula, R1 and R2 are alkyl group and aromatic group). In addition, multifunctional epoxy resin containing three or more glycidyl groups is added, and further biphenyl epoxy resin with a weight- average molecular weight of 20000-100000 is added. The insulating adhesive for multilayer printed wiring boards thus constituted does not contain halogen compounds at all which produce dioxin when burnt, and achieves flame retardancy for printed wiring board as per JIS C6481. |
