A technology from three suppliers to the medical device sector has been developed to create the potential for film products that combine the properties of TPE with the ability for calendering, and sealability via radio frequency (RF) welding.
In collaboration with O’Sullivan Films and Genesis Plastics Welding, Teknor Apex Company claims that its Medalist MD-500 Series elastomers eliminate the traditional disadvantages of TPEs in certain applications including fluid drainage and storage bags, cushioning bladders, and surgical pouches, exhibiting performance that is comparable to PVC in processing, bonding, assembly, and clinical handling.
While calendered PVC film is widely used in medical applications, traditionally 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 is reported to have 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 optimiSe 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.
“While there is pressure on medical device companies to replace PVC in a number of applications, the track record and excellent cost-performance profile of PVC have in the past made it difficult to replace,” said Elliott Pritikin, Global Medical Market Manager for the Thermoplastic Elastomer Division of Teknor Apex. “Recently, however, Medalist MD-500 Series elastomers have been commercially successful as alternatives to PVC in medical tubing, and now they are proving to offer clear-cut advantages over PVC in film products.”
Film made from Medalist MD-500 Series TPEs is reported by Teknor Apex to exhibit the same degree of strength as PVC film that is twice as thick. 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, claims the group.
“Teknor Apex started off by listening to the voice of the customer, consulting with manufacturers of medical devices to identify all of the regulatory and performance considerations that may arise in film applications and to learn how traditional TPEs and PVC compare,” said Richard Faulkner, Teknor Apex Medical Market Manager. “As in our development of compounds for tubing, we partnered with companies that have longstanding expertise in the target applications.”
Teknor Apex also collaborated with Genesis Plastics Welding, an ISO 13485:2003 certified medical device contract manufacturer. Genesis' proprietary radio frequency (RF) welding technology, ecoGenesis, enables sealing of polar and non-polar plastics, including film produced from a Medalist elastomer. While the alternative technique of heat sealing produces only a straight-line bond, RF welding with ecoGenesis makes it possible to form strong permanent bonds in complex geometric patterns, including sealing two mono-layered film to tubing producing traditional infusion bags.