COMPOSITION, DRY FILM, CURED PRODUCT, AND PRINTED WIRING BOARD

摘要

A composition, a dry film, a cured product, and a printed wiring board are provided to realize surface hardening and deep hardening by designing high absorbance in short wavelength and low absorbance in long wavelength. A composition is exposed with laser after forming a drying coating film. When the absorbance at the wavelength 400 nm is L400 and the absorbance at the wavelength 410 nm is L410, the absorbance L400 is 0.5~1.2 and the absorbance L410 is 0.01~0.5 per 25 mum width of a drying coating film before exposure. Also, the absorbance L400 is greater than the absorbance L410.