Injection molding machine makers and resin producers make it clear that silicone is here to stay for a growing number of medical market applications.
Among others, equipment makers Engel, Arburg and Toshiba provide processors with liquid silicone rubber and liquid injection molding solutions, while silicone suppliers Dow Corning, Momentive, Shin-Etsu, Wacker, Bluestar, NuSil and Applied Silicone are finding new ways to deliver the goods.
The companies were talking about what's new in the silicone field at the Medical Design & Manufacturing West and Plastec West trade shows, held Feb. 10-12 in Anaheim.
The demand for silicone components in the medical arena is growing faster than for thermoplastic ones, said Dale Bartholomew, East Coast technical sales manager at Toshiba Machine Co. America, of Elk Grove Village, Ill.
Globally, silicone usage is growing at 8-10 percent a year, according to NuSil Technology LLC's national sales manager, Bob Umland. That's in part because silicone suppliers like NuSil of Carpinteria, Calif., and global market leader Dow Corning Corp. of Midland, Mich., are targeting the industry with new materials and applications.
Among NuSil's recent developments is a comprehensive line of silicone materials for drug-delivery products. At Dow Corning, one target market is helping patients move from hospital care to home treatment, said Gary Lord, a new-business development leader for health care.
Equipment signals
Engel Machinery Co.'s small and midsized LIM machines are based on its Victory press platform, with tie-barless clamping units for processing LSR.
At the Anaheim shows, the firm opted to exhibit its lower-priced all-electric E-max injection press. On the show floor, a 110-ton E-max made pipette tips, using a 64-cavity mold.
“The market for the E-max is starting to lift off,” said Jim Moran, vice president of North American sales. The machine made its debut in 2007 in Europe, but hit the North American market just last year. York, Pa.-based Engel Machinery is a unit of Engel Holding GmbH of Schwertberg, Austria.
Moran said the E-max is well-suited for LIM, and LSR processing. “The E-max fits the market better” than Engel's E-motion machine, with its extensive controls that are perhaps too robust for most processors, he said.
“The E-max is 15 percent cheaper than E-motion models,” he added.
Engel will open its new, 75,000-square-foot technical center in Corona, Calif. in mid-March, as a replacement for a 20-year-old site in Santa Ana, Calif. Chris Kightlinger, western regional and technical sales manager, said the center will be supported by four servicemen, a parts manager — and perhaps a trainer, to take advantage of its state-of-the-art classroom.
The U.S. unit of Arburg GmbH + Co. KG, of Lossburg, Germany, is seeing greater demand for silicone catheters, drug-delivery systems and stomach-reduction bands, according to regional manager Jurgen Giesow. The country's aging population is pushing that growth, he said.
“We offer silicone on any of our machines — horizontal, vertical, shuttle rotary, convertible, hydraulic, hybrid or electric,” Giesow said. Over three decades, “we have done LIM from its first days” and offered technical support and expertise, “not just a molding machine,” he added.
Giesow said Arburg also has pushed the development of, and created a capability in, the foaming of silicone. Foaming “definitely opens opportunities for the silicone market, mostly outside medical,” he said.
More processors are turning such opportunities into new business, suggested Chris Mitchell, Toshiba's district sales manager in Ontario, Calif. Mitchell, who has been selling silicone machines for five years, said he is aware of 25-30 injection molders of LSR in his regional market alone.
Though geographically, Toshiba is seeing more demand for LSR processing equipment in California that in the East or the Midwest, Bartholomew said. Also, for molding silicone, “the sweet spot is 300 tons and under,” he added.
At the show, Toshiba molded an LSR retrieval tool for golf balls, on a 45-ton all-electric press. The injection unit was located outside a simulated clean room, and the clamping unit inside the clean room. Bartholomew said the machine offers faster cycle times, quicker response and greater dimensional accuracy than competing systems.
Integrity Mechanical LLC of Columbus, Ohio, built the 10-square-foot clean room, and Warthan Associates Inc.'s Technical Surface Solutions division installed anti-static flooring tiles. Kingson Mold and Machine Inc. of Brea, Calif., made the mold.
Material notes
To support the hospital-to-home transition, Dow Corning has extended its offerings with an easy and fast LSR with reduced temperature requirements and soft-skin silicone adhesives for wound dressings.
“We want to help people maintain their lifestyle,” Lord said.
He noted that the U.S. government has changed its regulations on antimicrobial treatments. “If a patient exits the hospital with a hospital infection, the government won't reimburse,” he said.
Important to such applications, according to Toshiba's Mitchell, is that “99.9 percent of the world's population does not have a negative reaction to silicone.”
Momentive Performance Materials Inc. of Albany, N.Y. — formerly GE Advanced Materials — in June introduced its StatSil antimicrobial silicone elastomer to the U.S. market, where it is gaining acceptance, said Lynn Colucci-Mizenko, global health-care marketing manager. The elastomer provides a built-in layer of protection to help minimize microbial growth in, or on, the human body, she said. Applications include catheters, wound drains and intravenous components.
As well, Momentive is seeing medical market potential for its LSR7000 series of platinum-catalyzed liquid silicone rubber, originally developed for specialty electronics applications. Medical-device designers are considering the LSR material for health-care applications because of its high optical transparency and physical stability.
Also used in wound-care and medical applications is Wacker Chemie AG's Silpuran-brand silicones. The silicones can be both extruded and injection molded, according to the Munich, Germany-based firm.
Spartanburg, S.C.-based Milliken & Co. incorporates a silver-based antimicrobial agent in a primary wound dressing, with the transfer of the exudate into a secondary dressing for changing it without disturbing the wound bed.
At the Anaheim shows, China's Bluestar Silicones introduced its Silbione skin adhesives, which are breathable, gas-permeable and biocompatible and suitable for scar management, said Karen O'Keefe, North American health-care market manager for Bluestar Silicones USA Corp. in East Brunswick, N.J. Government-owned China National BlueStar Corp. of Beijing formed Bluestar Silicones in February 2007 after acquiring the silicone business of Paris-based Rhodia Group.
In addition, Bluestar introduced a low-durometer Silbione LSR 4300 series for prosthetic liners and catheter balloons, among other applications. The U.S. unit has a facility in Ventura, Calif., for silicone and health-care applications, and another in Rock Hill, S.C., for mold making, textile coating and research and development.
New applications depend on R&D and in the health-care industry those efforts can be huge.
“At any one time, we may be working on three-dozen R&D projects,” NuSil's Umland said.
About 80 percent of the customized silicone formulations focus on customer needs, and 20 percent relate to NuSil-specific projects, he added. The company, which employs about 400, manufactures silicone compounds in Carpinteria and Bakersfield, Calif.; and in Irving, Texas.
Roughly 70 percent of NuSil's business involves health care, with the remainder in engineered materials for the aerospace, aircraft, electronics and photonics industries, Umland said.
Material maker Applied Silicone Corp. of Santa Paula, Calif., has carved out a niche by catering to the less-than-29-day silicone implant material market.
Applied Silicone focuses on supplying medical-implant-grade LSR, elastomer dispersions and silicone fluids, adhesives and gel systems.
Gayson Silicone Dispersions Inc. of Barberton, Ohio, is experiencing growth for its Silcopas line, by offering standard and customized color matching for LSR and room-temperature-vulcanization silicones.
Shincor Silicones Inc., of Akron, Ohio, manufactures high-consistency silicone rubber compounds and liquid-type silicone rubber for LIM, for its Tokyo-based parent company, Shin-Etsu Chemical Co. Ltd.
Also evolving are end markets for silicone and elastomer molded parts and silicone extruded components, according to processor MRPC in Butler, Wis.
“More of our customers are looking to partner with us because of our ability to provide multimaterial solutions,” said Mark Brandstaetter, MRPC vice president of sales and marketing.
“Our expertise in molding both rigid thermoplastics and elastomeric materials, coupled with our bonding technologies, provides us opportunities to produce components and assemblies that require multiple materials,” he said.
Reducing size is important as well, according to Brandstaetter.
“As medical devices continue to become smaller and multifunctional, we also have seen a need to produce parts that are small to micro in size,” he said.