Water-based crosslinkable coatings via miniemulsion polymerization of acrylic monomers in the presence of unsaturated polyester resin
✍ Scribed by John G. Tsavalas; Jan W. Gooch; F. Joseph Schork
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 223 KB
- Volume
- 75
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
Hybrid miniemulsion polymerization was performed with a three-component acrylic system of methyl methacrylate, butyl acrylate, and acrylic acid in the presence of a Bayer Roskydal TPLS2190 unsaturated polyester resin. Latexes were obtained in which the polyester resin was grafted to the acrylic polymer, forming a water-based crosslinkable coating. Grafting between the resinous component and the acrylic polymer is a feature different from the work of others who have attempted to combine the properties of both systems in water-based blends. Both emulsions and latexes were shelf-stable for over 6 months, shear-stable, and resistant to at least one freeze/thaw cycle. Resin-to-monomer ratios were studied as high as 1 : 1 (wt : wt), and total emulsion solids, as high as 45%. Monomer droplet and latex particle sizes were similar, suggesting evidence of the preponderance of droplet nucleation. A high level of crosslinking (Ͼ70%) during polymerization was observed in this particular hybrid system in contrast to those involving alkyd or polyurethane resins (Ͻ5%). Films, both homogeneous and hard, were achieved with exceptional adhesion. Electron microscopy showed the hybrid particle morphology to have internal domains of polyester resin in an acrylic matrix.