The photosensitive and physical and mechanical properties of a novel polysiloxane urethane acrylate (PSUA) for solder mask were investigated using real-time FTIR, DMTA and TGA. It is noted that PSUA showed a notable photosensitivity and a good compatibility with the acrylic monomers and resins. PSUA cured film exhibited excellent thermal property, tensile strength and toughness, and chemical resistance. The decomposition temperature of PSUA was 402 degrees C. Thermal weight losses of pure PSUA cured film at 300 degrees C were only 5%. Elongation percentage of PSUA cured film was up to 59%. PSUA resin can be used for solder mask materials for printed circuit. Technology performances of photosensitive imaging flexible solder mask containing PSUA answers operating requirements of the solder masker for printing circuit board. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 3035-3039, 2010