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Conference Paper Sheds Light on ‘Sunshine-Cure’ Polyurethanes

Tuesday, June 8, 2010

Natural sunshine provides sufficient energy to crosslink UV-cure wood-decking coatings based on polyurethane dispersions, a Bayer MaterialScience LLC representative said in a paper presented at the recent RadTech UV/EB 2010 Technology Expo and Conference.

The use of UV-cure polyurethane dispersions in coatings for exterior wood decking was reviewed by Charles Gambino, Bayer MaterialScience R&D specialist. Gambino compared the performance of “sunshine-cure” semi-transparent and opaque coatings at different field sites, and compared sunshine curing to curing by full-spectrum UV and UVA artificial-light sources.

Also reviewed was other testing directed at determining whether the system will cure under all light sources, evaluating chemical resistance against common household chemicals, and comparing how different curing sources affect hardness and abrasion.

“The results of the testing confirm that sunshine provides enough energy to crosslink UV-cure PUDs that will provide several years of performance on exterior decking,” Gambino said. “We have found that for outdoor applications the sun provides sufficient curing compared to artificial light. This type of curing could also be used for other outdoor applications, provided the object is not located in the shadows,” he said.

Gambino noted the significant market potential for wood-protection coatings and treatments, citing research by Freedonia Group that forecasts demand growth for wood-protection coatings and preservatives of 2.5% per year in the near term, to an estimated $3.3 billion in 2013.

Gambino’s presentation was based on a paper he co-authored with Bayer MaterialScience’s Michael Dvorchak, strategic technology manager-UV cure oligomers & PUDs government programs; Robert Wade, business development, coatings, adhesives, specialties; Christine Muroski, senior economic & strategic marketing specialist; and Karen Henderson, formerly with the company.

Bayer MaterialScience said the test results suggest that the technology represents a “viable competitor” in the market for wood-decking coatings. The company also cited other characteristics of formulated sunshine-cure systems, including storage stability; adhesion; flexibility of application by brush, roller and spray; rapid dry; and strong mechanical properties of the cured coating.