Presidential Green Chemistry Challenge: 2005 Greener Reaction Conditions Award
A UV-Curable, One-Component, Low-VOC Refinish Primer: Driving Eco-Efficiency Improvements
Innovation and Benefits: BASF developed a new automobile paint primer that contains less than half the amount of volatile organic compounds (VOCs) used in conventional primers. The new primer is also free of diisocyanates, a major source of occupational asthma. Use in repair facilities has shown that only one-third as much of this primer is needed compared to conventional primer and that waste is reduced from 20 percent to nearly zero.
Summary of Technology: The market for automotive refinish coatings in North America exceeds $2 billion for both collision repairs and commercial vehicle applications. Over 50,000 body shops in North America use these products. For more than a decade, automotive refinishers and coating manufacturers have dealt with increasing regulation of emissions of volatile organic compounds (VOCs). At first, coating manufacturers were able to meet VOC maximums with high-performance products such as two-component reactive urethanes, which require solvents as carriers for their high-molecular-weight resins. As thresholds for VOCs became lower, however, manufacturers had to reformulate their reactive coatings, and the resulting reformulations were slow to set a film. Waterborne coatings are also available, but their utility has been limited by the time it takes the water to evaporate. Continuing market pressures demanded faster film setting without compromising either quality or emissions.
Through intense research and development, BASF has invented a new urethane acrylate oligomer primer system. The resin cross-links with monomer (added to reduce viscosity) into a film when the acrylate double bonds are broken by radical propagation. The oligomers and monomers react into the film’s cross-linked structure, improving adhesion, water resistance, solvent resistance, hardness, flexibility, and cure speed. The primer cures in minutes by visible or near-ultraviolet (UV) light from inexpensive UV-A lamps or even sunlight. BASF's UV-cured primer eliminates the need for bake ovens that cure the current primers, greatly reducing energy consumption. BASF's primer performs better than the current conventional urethane technologies: it cures ten times faster, requires fewer preparation steps, has a lower application rate, is more durable, controls corrosion better, and has an unlimited shelf life. BASF is currently offering its UV-cured primers in its R-M® line as Flash FillTM VP126 and in its Glasurit® line as 151-70.
BASF's primer contains only 1.7 pounds of VOCs per gallon, in contrast to 3.5–4.8 pounds of VOCs per gallon of conventional primers, a reduction of over 50 percent. The primer meets even the stringent requirements of South Coast California, whereas its superior properties ensure its acceptance throughout the U.S. market. The one-component nature of the product reduces hazardous waste and cleaning of equipment, which typically requires solvents. Applications in repair facilities over the past year have shown that only one-third as much primer is needed and that waste is reduced from 20 percent to nearly zero. The BASF acrylate-based technology requires less complex, less costly personal protective equipment (PPE) than the traditional isocyanate-based coatings; this, in turn, increases the probability that small body shops will purchase and use the PPE, increasing worker safety.
This eco-efficient product is the first step in an automobile refinishing coating system for which BASF plans to include the globally accepted waterborne basecoat from BASF (sold under the Glasurit® brand as line 90). In the near future, this system can be finished with the application of a one-component, UV-A-curable clearcoat. The system will deliver quality, energy efficiency, economy, and speed for the small businessperson operating a local body shop, while respecting the health and safety of the workers in this establishment and the environment in which these products are manufactured and used. To fully support these claims, BASF has conducted an eco-efficiency study with an independent evaluation.