Title

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