| abstract |
In the present invention, in order to form a printed circuit board from a white cured film capable of achieving a high level of balance between pliability and high reflectivity with little reduction in reflectivity over time, a curable resin composition comprises the following: (A) a carboxyl group-containing urethane resin obtained using a non-aromatic compound having iosycyanate groups, (B) an aromatic-ring free, carboxyl group-containing resin; and (C) titanium oxide. The curable resin composition is cured by at least heating or exposure to active energy rays, and a ratio of the (A) carboxyl group-containing urethane resin and the (B) aromatic-ring free, carboxyl group-containing resin is within a range of 50 to 70: 50 to 30 by mass. A thermosetting resin composition contains (D) a thermosetting component, and a photocurable thermosetting resin composition contains (E) a monoacyl phosphine oxide photopolymerization initiator solely, or additionally (F) a bisacyl phosphine oxide photopolymerization initiator. |