Formulation variables determine how topcoats weather the storm

Tampa, Fla., February 1, 2012 — The weathering performance of polyurethane topcoats can be altered by changing variables such as pigment-to-binder (P/B) ratio, isocyanates index, resin/polyisocyanate selection, fillers and additives. Two Bayer MaterialScience LLC scientists set out to determine what effect modifying these variables has on the performance of two-component polyurethane topcoats used in corrosion protection applications, such as bridges, marine settings and stadiums.

At Society for Protective Coatings (SSPC) Conference 2012, Kurt Best, senior development specialist, and Ed Squiller, technical director, both of Bayer MaterialScience LLC, will detail the findings of a five-year study comparing some key formulating variables influencing weathering performance of aliphatic polyurethane topcoats in QUV-A and Florida exposure. The authors will present "2-Component Polyurethane Topcoats: Formulating Variables Affecting Performance in the Heavy Duty Corrosion Protections Market," at 4 p.m., Wednesday, Feb. 2, in Room 20. Their presentation is part of session abs82 and the Big Bridges, Big Solutions track.

Commercial topcoats and some lab formulas were used to illustrate raw material choices and how weathering performance plays out in both QUV-A and natural Florida exposure scenarios. The resulting performance of these coatings was compared using SSPC Paint 36 as a baseline. SSPC Paint 36 is often used in industrial maintenance and marine markets to define performance criteria for polyurethane topcoats.

According to Squiller, "The degree of weathering performance expected from a polyurethane topcoat changes, depending on the PVC, isocyanate indexing and polyol selection. Of the three formulation options tested, we found that the choice of acrylic polyol has the most significant impact on long-term weathering of the aliphatic polyurethane topcoat."

Best further explains, "We also discovered that there is poor correlation between accelerated QUV-A and natural Florida weathering in this study; thus, care must be taken when making conclusions regarding the durability of polyurethane topcoats. We believe Florida weathering is a better predictor of polyurethane topcoat durability."

About Bayer MaterialScience LLC:

Bayer MaterialScience LLC is one of the leading producers of polymers and high-performance plastics in North America and is part of the global Bayer MaterialScience business with approximately 14,700 employees at 30 production sites around the world and 2010 sales of 10.2 billion euros. The company manufactures high-tech polymer materials and develops innovative solutions for products used in many areas of daily life. The main segments served are the automotive, electrical and electronics, construction, medical, and sports and leisure industries. Sustainability is central to Bayer MaterialScience LLC's business and is based around the key areas of innovation, product stewardship, excellence in corporate management, social responsibility and respect for the environment.


Thomas Erdner, Phone: 412-777-5200

For more information about Bayer MaterialScience LLC's polyurethane coatings technology, call 412-777-3983 or visit

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