Super photo-base initiated organic-inorganic hybrid coatings by plural-cure mechanisms

Free-radical polymerization forms the core chemistry of a majority of commercial UV-curable coating system today. Rapid curing at ambient temperature using stable, single component coating systems form the key value proposition that such coating systems offer. However, owing to their limitations such as oxygen inhibition, volume shrinkage, toxicity profiles of reactive diluents (RD), and the limited chemistry available, efforts are being made to counter these challenges by innovating and exploring new systems that have the potential to replace the existing chemistries. Anionic polymerization is one such promising area that has the potential to introduce a wide variety of chemistries in the field of UV-curable coatings. A significant stride in this field has been the innovation of photo-labile bases in the UV industry and the diverse chemistries that these bases have brought to fore. The primary focus of the present study is use of a super photo-base generator (PBG) in catalyzing concomitant but independent reactions to develop organic-inorganic hybrid (OIH) coating networks by leveraging plural-cure chemistry. The super PBG has been used to initiate both Michael-addition (MA) reaction and sol-gel reaction concurrently, upon exposure to the UV source. Coatings have been formulated using uniquely designed acrylate functional oligomers (MA-acceptor), acetoacetate functional reactive diluents (MA-donors) and organo-silanes (sol-gel precursors), besides super PBG. The study highlights many technical and environmental benefits of these OIH coatings with potential for applications in advanced coatings and additive manufacturing