By Cameron Chai
Kerry Ingold, Senior Technical Service Expert at Bayer MaterialScience, will discuss the recently developed foam technology at the Polyurethanes Technical Conference that is taking place in Nashville, Tennessee from September 26 to 28. He will present a technical paper titled, "Measurement and Improvement of the Post-Mold Expansion of Rigid Polyurethane Foam.”
The manufacturers of rigid polyurethane foams are concerned about the quantity of the post-demold expansion revealed by foams. High post-demold expansion can reduce the performance of the foam and appearance of the final product and minimize the productivity. The presentation demonstrates how Bayer develops new foam technologies by evaluating the post-demold behavior in its laboratory. Kerry Ingold will also discuss a few foam systems developed by Bayer to minimize the amount of post-demold expansion. New foam systems from Bayer use various blowing agents, including cyclopentane, HFC 245fa and HFC 134a to minimize post-mold expansion. These new formulations will enhance the product appearance through flatter sides and will increase the foam’s performance and productivity by decreasing the demold time.
The company tested the application of the rigid polyurethane foam in residential refrigerators. The foam insulation makes significant contribution to energy efficiency and its insulating capacity can be improved by increasing the foam thickness. But, the increase in thickness leads to increased post-demold swelling.
The main reason for post-demold swelling is due to high temperatures that are attained in the foam’s core, once it is poured. This happens because the foam expands to fill the gaps left by the expanded and vaporized blowing agents and softening of the foam core after it reaches the glass transition temperature.