Written on 15.11.2010 - Technology
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Waterborne PU coatings based on PUDs offer better performance

According to Bayer MaterialScience (BMS), the process of selecting the proper waterborne coating for direct-to-metal (DTM) applications is complicated by necessary surface treatment, application requirements, cost of the coating and desired performance properties. No one coating can overcome all of these challenges, but waterborne polyurethane coatings provide a good starting point to meet the various performance requirements of today's industrial markets, says the company.

Dr. Raymond Stewart, senior R&D scientist, Bayer MaterialScience LLC, presented the findings of a study he performed with Margaret Kendi, associate research scientist, Coatings, Adhesives and Specialties, Bayer MaterialScience LLC, on waterborne polyurethane coatings for DTM industrial coatings.

Stewart noted that the study found that a single coat of the waterborne urethane PUD is as effective as multiple coats of the commercially available coatings and that the waterborne urethane coating has low volatile organic compound (VOC) levels. "We further found that the study succeeded in confirming that waterborne urethane coatings based on polyurethane dispersions have superior performance properties over commercially available coatings," said Stewart.

The presentation, "Waterborne Polyurethane Coatings for Direct-to-Metal Industrial Coatings – Challenges and Successes," was given as part of the Innovations in Industrial Liquid & Powder Coatings Session of Track B: Industrial Coatings II, at the North American Industrial (NAI) Coatings Show, held recently in Indianapolis. NAI, the largest industrial coatings conference in North America, is the only event that provides a technical programme and exhibits focused exclusively on industrial and protective coatings.

During his presentation, Stewart compared the different formulations of polyurethane dispersions (PUDs) for ambient or low-temperature cure with the benchmark formula, a commercially available latex emulsion coating. Stewart also discussed the advantages of each formulation with an emphasis on resin evaluation protocols for best utilisation of time and other scarce resources.