Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10397995 | Progress in Organic Coatings | 2013 | 8 Pages |
Abstract
The curing characteristics of clearcoats, including a thermal curing initiator (TRI) newly designed from O-imino-isourea and photo-initiator (PI), were investigated by means of different mono-curing and dual-curing pathways. The competitive relationship between TRI and PI on the curing pattern, reacting with acrylate double bonds in a clearcoat was elucidated by altering the UV and thermal sequence in the dual-curing process, through various experimental methods. From the rheological properties of clearcoats along the curing time, two dual-curing methods showed the different evolution of curing patterns. In the UV-thermal dual-curing case, the initial infusion of UV light promoted free radical polymerization during the subsequent thermal curing by generating considerable free radicals, and exhibiting a higher growth rate of elastic modulus during the curing in comparison with the thermal-UV dual-curing case. However, the final modulus value in the thermal-UV dual-curing case was higher due to the suppression of thermal curing by the steric hindrance in the UV-thermal dual-curing. The level of crosslinked networks in clearcoats via different curing steps can be explicitly figured out from the double bond conversion from FT-IR, curing pattern from rigid-body pendulum test, and scratch properties from nano-scratch test.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Process Chemistry and Technology
Authors
Ji Won Hwang, Kyung Nam Kim, Gil Sun Lee, Joon Hyun Nam, Seung Man Noh, Hyun Wook Jung,