What is said to be a breakthrough in PVC technology makes it possible for rigid PVC to replace PC in clear medical components, such as, Y-connectors, check valves, oxygen cannulae, drip chambers, and specimen containers.
Launched by Teknor Apex Co., Pawtucket, R.I., at last month’s MD&M West show, new Apex SCR rigid PVC compounds are based on an innovative chemistry that allows them to provide comparable strength and excellent clarity while reducing or eliminating the stress cracking that often occurs in PC at the interface with flexible PVC components such as tubing. The SCR compounds meet biocompatibility standards like ISO 10993-1 and USP Class VI, can be sterilized by EtO and heat methods, have good heat stability, and are easy to process. They also boast cost savings compared with resins that may be over-engineered for these applications.
Extensive testing data indicates that after prolonged contact with flexible PVC under conditions designed to induce stress cracking, the SCR compounds took over a week to two-and-a-half weeks to exhibit stress cracking—far longer than the few hours recorded for test samples consisting of conventional rigid PVC or a PC widely used in medical devices. As the same time, these compound provided the excellent physical properties that have been the chief reason why PC has been used in such applications: toughness, rigidity, and clarity.
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