A thermoplastic polyurethane film or sheet grade possesses high elastic recovery to prevent wrinkling and loss of snap.
Low elastic recovery and the presence of lube additives included to provide slip are two traits in a thermoplastic polyurethane (TPU) film or sheet grade that can be detrimental when it comes to medical manufacturing. The former can cause wrinkling when the TPU is applied to material with high elasticity and high-elastic recovery, and the latter can cause contamination. Developers at Deerfield Urethane Inc. (Whately, MA; www.deerfieldurethane.com) believe that two new products in their Dureflex line will provide medical manufacturers of a variety of products with the advantages of TPU material, without the drawbacks.
In other industries and in some medical applications, TPU film or sheet grades without high elastic recovery are suitable. But if used instead of rubber as a flat, invisible, washable elastic at waists, cuffs, and other openings for fabric apparel applications, low elastic recovery would cause undesirable wrinkling and loss of snap. The Dureflex X2133 material provides the breathability and durability typically associated with TPU film or sheet grades, while possessing high elastic recovery. It can also be used as a stand-alone film in demanding industrial elastic applications that require repeated, multicycle elongation and recovery.
TPU is inherently tacky and when used with little or no lube can stick to itself when coiled and cause equipment clogging or jamming. As a result, manufacturers often add lube additives to make TPU film or sheet grade more slippery. The problem for medical manufacturers is that these additives can discharge or interact with equipment or environments that must stay sterile. To avoid contamination in such applications, Deerfield has introduced X2140, which is additive free and specially formulated to provide high slip and low gloss without blooming. The film will not interfere with adhesion or inks. It exhibits hydrolysis and fungus resistance, and is recommended for applications that have continuous exposure to water and high-humidity environments. The X2140 can be used as a stand-alone film in demanding elastic applications, or can be used in fabric applications as a protective and adhesive layer.