This informative article was featured on the Engineering 360 website. It details the history of foam blowing agents and the environmentally friendly options available today (like ecomate) that let manufacturers eliminate the use of harmful HFCs.
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As far as outstanding insulating properties, it is hard to beat polyurethanes. The versatile chemistry allows the materials to solve many challenges, while providing underlying value to both industrial and consumer products.
Polyurethanes are formed by reacting a polyol with a diisocyanate or a polymeric isocyanate in the presence of suitable catalysts and additives. Because a variety of diisocyanates and polyols can be used in polyurethane production, a spectrum of materials can be produced to address specific applications.
Since its invention in the 1940s, polyurethane has emerged as one of the best insulators available. Most refrigerators and freezers are made with a metal outer shell, a plastic inner liner, and a layer of polyurethane foam insulation sandwiched in between. The foam material’s thermal properties help control the heat exchange and enable a streamlined manufacturing process.
Critical to making compact yet highly efficient polyurethane is the blowing agent. The blowing agent is a substance capable of producing a cellular structure by a foaming process. It is typically applied when the material is still liquid. During the manufacturing process, the blowing agent expands the foam, enabling it to fill cavities and providing excellent physical properties. The cellular structure helps reduce density even as it increases the material’s thermal insulation and stiffness.