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LSR more prevalent in sealing for life science sector

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NORTHBOROUGH, Mass.—Liquid silicone rubber has its place in sealing, especially in the life science industry and medical applications.

LSR's ability to be formed into complex geometries, fast cycle times through injection molding and its closed-loop system are primarily why it is becoming more prevalent in sealing applications for the life science industries, said Jim Hederman, senior product manager for Trelleborg Sealing Solutions, a business unit of Trelleborg A.B.

The material is injection molded, which Hederman said produces cycle times of about 30 to 45 seconds while compression molding cycle times can range from three to five minutes.

“It's cost effective in the respect that you have very short cycle times and the level of automation that can be used,” he said.

“The nature of LSR combined with injection molding makes it attractive from a cost standpoint.”

LSR also is ideal for automated process because the material can be injected right from the package into the mold without any handling.

Hederman said Trelleborg's LSR processing machines in Northborough are fully automated, with no operator handling the material until it is completely cured.

No handling means lower risk of contamination, which is attractive to the life science industry, as Food and Drug Administration cleanliness requirements only are getting stricter, Hederman said.

He said LSR is used in other sealing industries—medical, biotech and pharmaceutical—but the life science market is the widest application of the material.

Common products for the material include O-rings, bellows, diaphragms and pinch valves.

“It transcends itself,” Hederman said. “More food preparation devices are being made from silicone because it can withstand the temperatures. You see it in food and beverage, automotive and baby care. It really transcends many, many markets because of the diverse nature silicone can provide and the applications that it can be used in.”

Switching from a compression molding or transfer molding process to LSR and injection molding isn't simple. Hederman said manufacturers looking to break into the LSR market need to make sure they have the right kind of expertise because of LSR's different properties.

“From a manufacturer's standpoint, silicone gives the appearance that you can take your experience from compression molding or transfer molding via press or tools and start making silicone parts,” the executive said.

“It's not that simple. It's a very complex operation. We've seen so many people start up with liquid injection molding and silicone, and then very quickly back out of the business.”

In addition to Northborough, Trelleborg operates LSR facilities in Stein Am Rhein, Switzerland; Pernik, Bulgaria; and Madrid, Spain.

The facilities combine to serve the life sciences, automotive, baby care and industrial industries worldwide.