CLEVELAND—Liquid silicone rubber is growing rapidly in the medical field, according to two industry experts who spoke at Plastics in Medical Devices 2014 May 7 in Cleveland.
Mark Hammond, general manager at GW Silicones, said medical was the fastest growing end market for silicone from 2001-11.
Hammond said the material has a number of properties that lend itself for use in medical. It is chemically inert; bacteria resistant; biocompatible; easily colored; temperature flexible; fatigue and compression-set resistant; chemical resistant; consists of high elongation; and can contain insulative or conductive properties by adding fillers.
Silicone is cured with platinum, which Hammond says provides manufacturers with quicker cure times. He added that another key advantage for original equipment manufacturers is consistency in raw material prices, noting that if anything, silicone has come down in pricing over the last 10 years.
There are drawbacks, mainly higher air permutations and a high coefficient of friction—or that it won't slide easily over a flat surface. Hammond cautioned manufacturers looking to jump into the silicone market, saying it requires the right kind of equipment and expertise.
“Anyone can buy their way into silicone molding, but the real trick with silicone molding is how did you do at keeping that cell running at peak efficiency,” he said. “It's definitely a commitment when it comes to silicone molding.”
Jim Miller, general manager at Qure Medical, said at the conference—hosted by Plastics News—that there are a number of medical applications for silicone, mainly seals. He said silicone's excellent compression-set properties lend themselves to producing a strong O-ring.
Silicone is used in other fluid management products, including plunger tips, diaphragms, catheters and pump tubing. Miller said because silicone doesn't react with blood, stomach acid or many of the chemicals used in the medical field, it is a good choice in products that deliver or remove fluids from the body.
Its non-reactive properties lends itself to use in drug delivery products—such as sleeve stoppers, valves, septums, diaphragms and IV components—the medical surgical arena, consumer health care and safety applications, Miller said.
Silicone is widely used in feeding applications, primarily because of the soft nature of the product, he said. Soft silicone doesn't react to feeding solution being put in and acts as a strong barrier to blood and other organisms.
Miller said the material can be molded onto thermoplastic as well, which creates a product applied during optical surgery used to cushion the eye while doctors perform work inside.