| 摘要 |
<p>This improved flexible printed circuit board comprises an insulating material (1) and a conductive substance (2). (1) contains a weakly heat-swelling resin, which has a structural unit represented by general formula (I), (II) or (III), where Ar1 represents a 4-valent aromatic gp.; Ar2 represents the gps. (i), (ii) or . R1-R8 are independently the same or different, lower alkyl gps., lower alkoxy gps. or halogen atoms; n1-n8 are independently 0, 1, 2, 3 or 4. In the formula (II) at least one of (R1)n1 and (R2)n2 must be a methoxy gp. The insulating material (1) has a bending resistance against more than 5,000 bendings and a linaer swelling coefft. of 7 x 10 power (-5) (K(-1)) or less. The flexible printed circuit board is produced by directly coating a soln. of a weakly swelling resin contg. a polyamidoimide precursor on a conductive substance and hardening it.</p> |
