Interfacial Studies of Crosslinked Urethanes: Part IV. Substrate Effect on Film Formation in Polyester Waterborne Polyurethanes

Document Type

Article

Publication Date

9-1-1999

Department

Polymers and High Performance Materials

Abstract

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.

Publication Title

Journal of Coatings Technology

Volume

71

Issue

896

First Page

73

Last Page

78

Link to Full Text

Find in your library

Share

COinS