When designing a polyurethane elastomer, selecting the best polyol for a specific application can be the difference between making a high-quality product or a low performance one. A good understanding of the inherent characteristics of each polyol chemistry and the key properties and environmental exposures for a given application are keys for making a proper material selection.
What are the Polyether Polyol options that exist in selecting the best polyol for a specific polyurethane application?
Polyether polyols account for about 80 % of the polyol types used in polyurethane, polyurea and polyisocyanurate applications. Polyurethane foam products, Spandex fibers and CASE (Coatings, Adhesives, Sealants, and Elastomers) applications all utilize a diverse family of polyether polyols. The largest polyether polyol market is in flexible foams, where polypropylene glycol based polyols are dominant. PTMEG is the main soft segments of Spandex polyurea elastic fiber, cast thermoset polyurethane elastomers, thermoplastic polyurethane elastomers (TPUs), thermoplastic polyester and polyamide elastomers (TPEEs & TPEAs).
What are key attributes of polyurethanes based on polyether polyols?
Polyether-based polyurethanes exhibit excellent resistance to hydrolysis, even at higher temperatures. They are the preferred material for applications involving immersion in water or good property retention in warm and humid environments.
Polyether polyols have low glass transition temperature (Tg), which imparts good retention of physical properties and impact resistance at very low temperatures. They are the proper choice for applications where urethane parts are expected to perform in very cold environments and provide cushioning. Examples are flexible foam for automotive cushioning, bedding and furniture.
Polyether-based polyurethanes exhibit higher rebound (resilience) compared to polyester-based polyurethanes.
Polyethers impart lower hysteresis or heat build-up, which make them a preferred material for dynamic applications like wheels, casters and rollers.
Polyether-based polyurethanes, due to their higher resilience, offer better performance in applications where impingement abrasion is the dominant form of wear. This is especially true for PTMEG based elastomers.
What are the end-use market shares for polyether polyols by application area?
The major market for polyether polyols is in foam products, with flexible foam representing the dominant area. Automotive cushioning and furniture are the major drivers of PPG based polyether polyol volumes. Automotive coatings are another significant market area. For PTMEG polyols, spandex elastic fibers represent about 85% of total demand for this family of polyols.