| abstract |
Provided are a polyurethane and a curable composition capable of obtaining an overcoat film for a flexible wiring board excellent in low warpage, flexibility, long-term insulation reliability, and wiring breakage suppression. Formula (1) (In the formula (1), n R 1 s each independently represent a 1,2-phenylene group or a 1,2-phenylene group having a substituent, and (n + 1) R 2 s independently represent carbons. (The hydrocarbon group of number 3-9 is represented, and n represents the integer of 1-50.) Structural unit of formula (2) (In the formula (2), R 3 represents a divalent organic group having 6 to 14 carbon atoms.) Structural unit of formula and formula (3) (In the formula (3), R 3 represents a divalent organic group having 6 to 14 carbon atoms, and R 4 represents a methyl group or an ethyl group.) Polyurethane having a structural unit of |