Novel reworkable resins: Thermo- and photo-curable di(meth)acrylates

Abstract

Theaimofthestudyreportedin thispaperwastodevelopnewdi(meth)acrylateshavingaromaticunitsandthermallydegradable units in their molecules. It was also the aim to clarify the photo-curing and degradation properties of the new monomers. Di(meth)acrylates having aromatic units and thermally degradable units were synthesized. As thermally cleavable linkages, tertiary ester moieties were incorporated into the di(meth)acrylates. Three types of processes for curing and degradation of the cured resins were studied: thermal curing and thermal degradation; thermal curing and photodegradation; and photo-curing and thermal degradation. In the thermal curing and photodegradation process, di(meth)acrylate films containing a thermally induced radical initiator and a photoacid generator (PAG) became insoluble in solvents on heating. The cured films became soluble in solvents after ultraviolet irradiation followed by baking. The re-dissolution behaviors were strongly affected by the structures of the PAGs. Amechanism for the photo- or thermo-curing and photoassisted thermal degradation was studied using Fourier transform infrared, 1H NMR, thermogravimetric, mass spectrometric and size exclusion chromatographic analyses. © 2009 Society of Chemical Industry.