Nashville, Tenn., September 26, 2011 — Along with density and thermal conductivity, the amount of post-demold expansion exhibited by a foam is one of the most critical properties to processors of rigid polyurethane foams. High post-mold expansion can hurt the foam’s performance, detract from the final product’s appearance and reduce a manufacturer’s productivity.
Bayer MaterialScience LLC Senior Technical Service Specialist Kerry Ingold will discuss the latest foam technology developed to reduce post-demold expansion of rigid polyurethane foams during his presentation, “Measurement and Improvement of the Post-Mold Expansion of Rigid Polyurethane Foam,” at the Polyurethanes Technical Conference sponsored by the Center for the Polyurethanes Industry. The conference is being held Sept. 26 – 28 in Nashville, Tenn. The paper is also authored by Steven Schilling, senior principal scientist, Polyurethanes, Bayer MaterialScience LLC.
The presentation describes how Bayer assesses the post-demold swelling behavior during development of new foam systems in its laboratory and discusses some of the causes of post-demold expansion. Ingold will give information on some of the foam systems Bayer has developed to reduce the amount of post-demold expansion.
Their testing focused on the use of rigid polyurethane foam in household refrigerators. In household refrigerators, the foam insulation contributes greatly to energy efficiency, and one obvious way to increase the insulating ability of the foam is to increase its thickness. However, with increased thickness comes increased post-demold swelling.
Schilling and Ingold conclude that post-demold swelling is primarily a result of high temperatures reached in the foam’s core soon after it is poured. This is due to the foam’s expansion to fill spaces left by vaporized and expanded blowing agents, and foam core softening after it reaches its glass transition temperature.
Bayer’s new foam formulations use different blowing agents, including HFC 134a, HFC 245fa and cyclopentane, to reduce post-mold swelling. These formulations will help increase foam performance and manufacturing productivity by reducing the demold time and improving appearance through flatter sides.
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.
For more information about Bayer MaterialScience LLC's polyurethanes, call 412-777-7454 or visit www.bmsnafta.com.
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Name: Tom Erdner
Company: Bayer MaterialScience