Interfacial Studies of Crosslinked Urethanes: Part IV. Substrate Effect on Film Formation in Polyester Waterborne Polyurethanes
Polymers and High Performance Materials
These studies examine the effect of substrate surface tension on crosslinking reaction sin water-borne polyurethanes (PUR) applied to tin-plated steel, steel, polypropylene (PP), thermoplastic olefin (TPO), and glass. The results show that, relative to tin-plated steel, removal of tin-plating from a steel substrate increases isocyanate (NCO) consumption by 42% near the film-substrate (F-S) interface. When PUR is allowed to crosslink on steel, PP, TPO, and glass, the NCO concentration is greater at the film-air (F-A) interface. Furthermore, crosslinking reactions result in a greater amount of urea-hydrogen bonded species near the F-S interface for all substrates. While an increase of substrate surface tension decreases the amount of urea-hydrogen bonded carbonyl groups near the F-S interface, TPO was found to exhibit different behavior due to talc stratification near the surface. In this case, the presence of talc in WB-PUR coatings or thermoplastic substrates decreases the amount of hydrogen-bonded species and increases NCO consumption.
Journal of Coatings Technology
Urban, M. W.,
Allison, C. L.
(1999). Interfacial Studies of Crosslinked Urethanes: Part IV. Substrate Effect on Film Formation in Polyester Waterborne Polyurethanes. Journal of Coatings Technology, 71(896), 73-78.
Available at: http://aquila.usm.edu/fac_pubs/4778