Here's the bottom line up front—platinum-cured silicone is the exceptional choice for medical, pharmaceutical, and biotech tubing applications, as well as medical devices that require extended contact with tissues and bodily fluids. It's one of the most versatile elastomers available due to its broad working temperature range (-80°F to 420°F), choice of durometer options (20 to 80 Shore A), biocompatibility, high dielectric strength, and its ability to be pigmented to virtually any color. For these reasons and more, utilization of platinum-cured silicone has continued to expand into areas that traditionally employed materials such as PVC, urethanes, natural rubber, and peroxide-cured silicones, which require post-curing.
There are basic advantages over plastic when extruding silicone. Since it's a thermoset material, there are none of the high temperature hazards associated with plastic extrusion. Additionally, equipment can be simpler in design, while maintaining exacting tolerance requirements. The extrusion process requires no cooling/processing with water, eliminating pyrogenicity concerns. Silicone, having a wide thermal stability range, does not experience the scorch potential during extrusion normally associated with plastic processing, and equipment clean-up is easier since silicone can be removed without melting or burning.
From a finished product perspective, silicone is low in leachables and extractables, and proves unsurpassed in biocompatibility. Silicone can be sterilized by all standard means, including steam, Ethylene Oxide, or gamma radiation methods. Because silicone tubing is highly flexible, it is ideal for aseptic fluid transfer, peristaltic pumping, or filling operations. Silicone can be extruded in a wide variety of profiles/configurations, allowing it to be tailored to virtually any application.
Rob Wilkinson is director of quality at Helix Medical. Visit Helix Medical at www.helixmed.com.