Etch-resistant inkjet inks for manufacturing printed circuit boards

A method of inkjet printing comprising the steps of:

• forming a protected area on a metal or glass surface by printing and curing on the metal or glass surface a radiation curable inkjet ink comprising:
• an adhesion promoter including:
• at least one free radical polymerizable group selected from the group consisting of an acrylate, a methacrylate, an acryl amide, and a methacryl amide;
• at least one aliphatic tertiary amine;
• and
• at least one carboxylic acid or salt thereof, wherein
• the carboxylic acid is linked to the at least one aliphatic tertiary amine via a divalent linking group selected from the group consisting of an optionally substituted methylene group and an optionally substituted ethylene group;
• removing metal or glass from an unprotected area of the metal or glass surface by etching;
• and
• at least partially removing the printed and cured radiation curable inkjet ink from the protected area of the metal or glass surface.