PURPOSE: To improve flexibility, long-term heat resistance, thermal strength and solder heat resistance by using specific thermoplastic resin and epoxy resin and by compounding them in a specific ratio.
CONSTITUTION: The title composition is constituted of thermoplastic resin (constituent A) selected from a group comprising poly-sulfone, polyether sulfone, polyarylate, polycarbonate, poly-arylsulfone and polyhydantoin, epoxy resin (constituent B) and a curing agent. The compounding ratio between the constituent A and the constituent B is set in A:B=4:1 to 3:7 in the weight ratio. Thereby an insulative base and a metal leaf constructing a flexible printed circuit board can be bonded easily and firmly and, in addition, flexibility, long-term heat resistance, thermal strength and solder heat resistance being excellent can be obtained.
YAMAMOTO HIROSHI
MAZAKI SHIRO
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