We investigated the formulations of acrylates which were applicable to UV-C LED lamps. The mixtures of acrylate monomers and photoinitiators were placed on silicon wafer or sandwiched between a silicon plate and a CaF 2 plate to obtain sample films. The films were irradiated by UV-C LED lamps which emit 265, 285, and 300 nm-lights. The effect of initiators, irradiation wavelength, and atmosphere on the conversion of the acryl unit was investigated using FT-IR spectroscopy. We found that the photoinitiator O-benzoyl 2,3-butanedione monooxime was the most effective photoinitiator for 265-nm light. The effect of atmosphere in the system was clearly observed.

We investigated the formulations of epoxy resins which were used with deep-UV LED lamps. The mixtures of epoxy monomers and photoacid generators (PAGs) were placed on a silicon wafer to form films. The films were irradiated by deep-UV lamps which emit 265, 285 or 300-nm light. The effects of the PAGs, irradiation wavelengths, and film thicknesses on the reactivity were investigated by FT-IR spectroscopy and a photo-DSC study. We found that a sulfonium salt having a thiophenyl moiety was the most effective PAG. We also found that less than 100-m thick films were effectively cured by irradiation from the deep-UV LEDs.

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