Influence of functional group content in hydroxyl-functionalized urethane methacrylate oligomers on the crosslinking features of clearcoats

Young Gun June, Kevin Injoe Jung, Dong Geun Lee, Subin Jeong, Tae Hee Lee, Young Il Park, Seung Man Noh, Hyun Wook Jung

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Crosslinking characteristics and surface mechanical properties of radical and urethane dual-curable clearcoats were investigated by changing quantities of C=C bonds and OH groups in hydroxyl-functionalized urethane methacrylate oligomer (HFUMO) resins. The isocyanate blocked with a thermal radical initiator (BL-Tri-cHD) was utilized as a hybrid dual-curable thermal crosslinker to expedite the crosslinking of the main resin. The dual reactions between various HFUMO resins and BL-Tri-cHD were efficiently monitored via Fourier transform infrared spectroscopy to measure the peaks before and after curing. The influence of each functional group (C=C bond or OH group) in HFUMO on the initiation and development of crosslinking in dual-curable clearcoats was investigated by real-time measurements using rotational rheometer and rigid body pendulum tester. Temperature-dependent mechanical properties of cured films were confirmed through dynamic mechanical analysis. The surface mechanical properties of cured clearcoat films were also evaluated via the nanoindentation and nanoscratch tests, demonstrating the variation in surface resistance with respect to the C=C bond content and the OH value. Thus, the low-temperature curing and desired mechanical properties of clearcoats can be optimized by adjusting the content of the functional groups in a HFUMO and using a dual-curable crosslinker to simultaneously generate both radical and urethane crosslinking reactions.

Original languageEnglish
Pages (from-to)229-237
Number of pages9
JournalJournal of Coatings Technology and Research
Issue number1
Publication statusPublished - 2021 Jan


  • Clearcoat
  • Crosslinking dynamics
  • Dual-curable crosslinker
  • HFUMO binder
  • Low-temperature curing
  • Surface resistance

ASJC Scopus subject areas

  • Chemistry(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry


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