Scratch and recovery characteristics of automotive clearcoats containing blocked polyisocyanate crosslinkers

Seung Man Noh, Joon Hyun Nam, Jung Kwon Oh, Hyun Wook Jung

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Scratch characteristics and self-recovery behaviors of automotive clearcoats including newly designed silane-modified blocked polyisocyanate (SMBI)1 as an organic–inorganic hybrid crosslinker were compared with those with the commercially well-known crosslinkers such as blocked HDI-based and blocked IPDI-based polyisocyanates. To extensively scrutinize the effects of various crosslinkers with different chemical structures on the chemical and mechanical properties of clearcoats themselves, rigid-body pendulum tester analysis, creep-recovery analysis, and FTIR analysis were performed, resulting in a noticeable variation in curing features and crosslinking networks. Employing the overall coating systems by depositing clearcoats with different crosslinkers above the same undercoats on galvanized steel, the scratch behaviors on the surface of the outermost clearcoat layer were examined via the nano-scratch tester for scratch depth profiles and atomic force microscopy for three-dimensional scratch images, under various self-reflow temperatures and duration time periods. The results demonstrated that the SMBI crosslinker induced a considerably higher degree of crosslinked networks, through the reaction of urethane bonds and silanol bonds in clearcoats, in comparison with the blocked HDI and IPDI polyisocyanates. Also, the recoverable behaviors of scratched clearcoats containing different blocked polyisocyanates were affected by the intrinsic chemical structures of crosslinkers, as well as scratch-recovery conditions such as external temperatures and duration times.

Original languageEnglish
Pages (from-to)85-95
Number of pages11
JournalJournal of Coatings Technology Research
Volume12
Issue number1
DOIs
Publication statusPublished - 2014

Fingerprint

Polyurethanes
recovery
Silanes
Recovery
test equipment
silanes
creep analysis
Pendulums
Crosslinking
Chemical properties
urethanes
Curing
Atomic force microscopy
Creep
pendulums
crosslinking
rigid structures
curing
chemical properties
Steel

Keywords

  • Clearcoats
  • Scratch recovery
  • Self-reflow
  • Silane-modified blocked polyisocyanate

ASJC Scopus subject areas

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

Cite this

Scratch and recovery characteristics of automotive clearcoats containing blocked polyisocyanate crosslinkers. / Noh, Seung Man; Nam, Joon Hyun; Oh, Jung Kwon; Jung, Hyun Wook.

In: Journal of Coatings Technology Research, Vol. 12, No. 1, 2014, p. 85-95.

Research output: Contribution to journalArticle

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