Improving the properties of polyurethane soft-touch coatings:
Chicago, April 21, 2008 - The many positive properties of plastic make it the material of choice for countless applications ranging from automobiles to children's toys. However, the drawbacks of plastics - such as an easily scratched surface and yellowing during weathering - have driven the coatings industry, led by Bayer MaterialScience (BMS) LLC, to develop polyurethane coatings that protect the plastic substrate while providing a luxurious, soft feel. These "soft-touch" coatings have evolved over time to overcome obstacles including tightening VOC restrictions and adhesion loss due to creams and insect repellants that cause the coatings to soften and scratch off.
Amy Wylie, senior R&D specialist, plastic coatings, BMS, explores improvements made to the formulations of waterborne soft-feel resins to achieve improved adhesion, cream resistance and haptic (soft feel) properties in her paper: The New Age of Waterborne Soft-Touch Coatings, co-authored by Dr. Torsten Pohl, director of Business Development Industrial Coatings, and Bayer MaterialScience AG's Dr. Christoph Irle, manager of Business Development for 2K Waterborne Applications. Wylie will present the paper at the 2008 Coatings for Plastics Symposium, which takes place April 21-23, 2008, at the Westin Yorktown Center in Chicago. BMS is also offering a closer look at the latest in 2K polyurethane soft-touch coating technology at booth #9 at the event.
Automotive companies have been applying 2K polyurethane soft-touch coatings to the interiors of cars since the early 1990s. As a result, the automotive market has played a major role in driving the demand for coatings specifications for great appearance, excellent resistance properties, rapid cure, ease of application, environmentally friendliness and low cost. This, compounded by tightening governmental regulations regarding the allowable amount of VOCs at plant sites, has resulted in the accelerated evolution of soft-touch polyurethane coatings from solvent borne - which resulted in high levels of VOCs - to 2K waterborne chemistry utilizing polyurethane dispersions.
By utilizing waterborne two-component polyurethane resins, the coating formulator can achieve a variety of softness and resistance levels. The authors found that choosing a particular functional and non-functional polyol combination is important when trying to improve properties such as thermal yellowing, hydrolytic stability and cream resistance.
"Initially, in order to achieve increased barrier resistance in waterborne soft-touch coatings the formulator was forced to choose harder, less flexible polyols. Coaters had a hard time selling these new soft-touch coatings to the auto makers because altering the coating to pass more stringent auto specifications caused the coating to feel less soft," said Wylie. "To explore these challenges, we conducted testing to evaluate the effects of resin choice on hydrolytic stability, yellowing resistance and cream resistance. We then utilized these results to create a matrix of different blend amounts that were evaluated for suntan lotion/DEET resistance, perspiration resistance and grease staining resistance," she explained.
The authors expect the coatings industry to continue to use automotive specifications to benchmark the quality of coatings. Creating soft-touch coatings that meet increasingly stringent automotive market specifications as well as ever-shrinking VOC thresholds is a challenge the coatings industry will face for years to come.
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 nearly 15,400 employees at 30 sites around the world and 2007 sales of 10.4 billion euros. Business activities are focused on the manufacture of high-tech polymer materials and the development of 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. Our inorganic basic chemicals unit produces chlorine and related essential products for the chemicals industry. Let us give life to your vision. Bayer MaterialScience - Where VisionWorks.
Bayer Corporation, headquartered in Pittsburgh, is a subsidiary of Bayer AG, an international health care, nutrition and innovative materials group based in Leverkusen, Germany. In North America, Bayer had 2007 net sales of 8.1 billion euros and employed 16,800 at year end. Bayer's three subgroups, Bayer HealthCare, Bayer CropScience and Bayer MaterialScience, improve people's lives through a broad range of essential products that help diagnose, prevent and treat diseases; protect crops and enhance yields; and advance automobile safety and durability.
Tom Erdner, Phone: 412-777-5200
For more information about waterborne soft-touch coatings, call 1-800-662-2927, e-mail email@example.com or visit www.bayermaterialsciencenafta.com.