Photocuring resin composition, dry film, curing product and print circuit board

Abstract

The invention provides a photocurable resin composition, dry film, cured substance and printed circuit board. The invention provides a photocurable resin composition which is fully coloured, has high photosensitivity under the exposure of ultraviolet ray and laser such that it has good curing depth, in the mean time, adjusting absorption in the ultraviolet region by using red or yellow colorant as well as oxime ester initiators. The photocurable resin composition which may develop through alkaline aqueous solution contains (A) carboxylic acid-containing resins, (B) red colorants, (C) oxime ester initiators and (D) compounds having more than two unsaturated alkene groups in the molecules.

Description

technical field [0001] The present invention relates to a photocurable resin composition developable with an alkaline aqueous solution, especially a composition for a solder resist exposed to ultraviolet light or laser light, its dry film, cured product, and a printed circuit board. Background technique [0002] Typically, solder resist is formed to protect copper circuits. It is also effective in that discoloration caused by heat and moisture of the copper circuit, electrical discoloration, defects and dirt on the copper circuit cannot be seen. [0003] A film pattern is formed by coating a solder resist on a glass epoxy substrate with a copper circuit, exposing it to an image, developing it, and curing it with heat. Since the copper circuit is formed on the base material, when a solder resist is applied or laminated, the resist film thickness is thicker on the base material, thinner on the copper circuit, and thinner at the edge of the copper circuit. [0004] As a resul...

AI Technical Summary

Problems solved by technology

[0004] As a result, if the tinting strength is insufficient at the edge of the circuit where the copper circuit tends to become thin, there is a problem that the copper discolors in the heat history after the solder resist is formed, and only the thin part discolors and can be seen in appearance.

However, phthalocyanine compounds have a large absorption in the ultraviolet region, which is disadvantageous in obtaining a curing depth

[0008] In addition, commercially available ultraviolet exposure equipment has differences in ultraviolet wavelength distribution due to lamps.

Therefore, there is a problem that it is difficult to develop a solder resist with the same resolution using a different exposure device (lamp) among phthalocyanine compounds whose absorption changes greatly in the ultraviolet region (especially 350nm to 400nm).

[0010] Therefore, the presence of a light absorber such as a colorant causes the following problems: it is not only disadvantageous for high-sensitivity, but also prevents light from being transmitted to the bottom, resulting in undercuts

In order to prevent this phenomenon, if the amount of photopolymerization initiator is reduced, high-sensitivity exposure cannot

On the other hand, when the amount of the phthalocyanine compound is adjusted so that undercutting does not occur and the concentration of the photopolymerization initiator is increased, sufficient photosensitivity can be obtained, but the copper circuit cannot be hidden due to insufficient tinting power. Discoloration of the edge

Images