WEB EXCLUSIVE: Liquid fluorosilicone elastomers are used for injection molding medical parts with higher chemical resistance than ordinary LSR. Fluorosilicones resist alcohols, other solvents, oils, and dimethyl silicone lubricants used in syringes, suture needles, etc. Fluorination may also increase resistance to stomach acids. While these LSRs are typically fluorinated to a 20% to 50% level, NuSil Technology LLC
, Carpenteria, Calif., has introduced what it says is the first 100% fluorinated LSR for long- or short-term medical implants. According to Brian Reilly, marketing and sales director for medical implants, this product was developed in response to customer requests for even higher chemical resistance. He adds that fluoro-LSRs are sometimes used in drug-delivery devices because their molecular structure facilitates enhanced control over release of many pharmaceutical active ingredients that are compounded into the elastomer.
NuSil’s new MED-5440 is a translucent, two-part LSR with 1:1 mix ratio and durometer of 40 Shore A. Processing and cure speed are similar to those of standard LSR, Reilly says. Appplications can include septums, o-rings, or gaskets for which swelling is a concern when the device is exposed to certain agents or environments.