Calendered medical-grade TPEs provide a real-world alternative to PVC in bags, bladders and pouches

New technologies from three cooperating suppliers to the medical device market possible film products that combine the advantages of thermoplastic elastomers (TPEs) over PVC, the quality benefits of calendering, and the sealing efficiency of radio frequency (RF) welding, it was announced today by Teknor Apex Company. In collaboration with O'Sullivan Films (Winchester, VA) and Indianapolis-based Genesis Plastics Welding (Booth 3137), Teknor Apex Company has demonstrated that films produced from its Medalist® MD-500 Series elastomers eliminate the traditional disadvantages of TPEs in such applications as fluid drainage and storage bags, cushioning bladders, and surgical pouches, exhibiting performance that is fully comparable to PVC in processing, bonding, assembly, and clinical handling. In fact, tests by Teknor Apex and cooperating customers have shown that Medalist MD-500 Series TPEs provide a number of property improvements over PVC, along with substantial savings in weight and cost, according to Elliott Pritikin, global medical market manager for the Thermoplastic Elastomer Division of Teknor Apex. While calendered PVC film is widely used in medical applications, traditional TPEs have not performed well in calendering, a process which typically provides better thickness uniformity, more consistent physical properties, and greater thermal stability than film extrusion. Working with Teknor Apex, O'Sullivan Films has demonstrated that Medalist® MD-500 Series medical elastomers can be formulated for successful calendering. "Our company has attempted to calender a wide range of plastics besides PVC and concluded that most are simply not calenderable," noted Chuck Stronach, O'Sullivan Films commercial manager for healthcare products. "We were intrigued to discover that Medalist 500 Series compounds can be adapted for this process, and together with Teknor Apex we carried out a lot of R&D work to optimize the production and properties of Medalist calendered films." Film and bag applications for Medalist MD-500 Series TPEs include cushioning bladders (for mattresses, wheel chairs, and gurneys); IV and saline bags; medicine storage and delivery pouches; bags for enteral and parenteral nutrition storage and delivery; dialysis bags; and surgical pouches. Two of the greatest advantages cited by Mr. Pritikin involve: ? Raw material economy. Film made from Medalist MD-500 Series TPEs exhibits the same degree of strength as PVC film that is twice as thick (see table). ? Weight savings. Because the Medalist compounds are 30% less dense than flexible PVC and can be down-gauged without compromising strength, finished products can be 66 to 70% lighter. In addition, Medalist elastomers are available at lower hardness ranges than flexible PVC, provide a broader processing window, exhibit greater elasticity and tear strength, have superior flexibility and impact strength at low temperatures, are less permeable to nitrogen and moisture, and have a wider range of service temperatures. These TPEs exhibit 25% less color change upon exposure to gamma irradiation than standard (i.e., not gamma-stable) grades of flexible PVC.