Originally Published EMDM October
2001
PRODUCT UPDATE
Nova Chemicals
A new grade of acrylic styrenic copolymer is more cost-effective than acrylic, provides the same clarity, and demonstrates superior resistance to alcohol, blood, and lipids. NAS 90 resins from Nova Chemicals (Fribourg, Switzerland) are used in a broad range of medical applications, including chest evacuators, filter and monitor housings, and a variety of valves and meters.
"Our customers find that NAS products deliver value in clear applications, meet USP Class VI specifications, and can be sterilized by either gamma radiation or EtO methods," says Richard Speir, Nova Chemicals European marketing director for high-performance styrenics.
The company offers a number of grades of materials that offer quality physical properties and processing advantages. Speir says most customers are looking for quality performance and consistent and easy processing from their material.
"OEMs consider the total value themselves. Individual medical OEMs measure value in different ways, but the common components are product performance, total manufacturing cost, quality of the material, and a range of medical approvals," says Speir.
Schäfer Polymer GmbH
Compounds based on styrene copolymers are offering application possibilities in the field of highly flexible moulded parts with excellent statical and dynamical properties. A range of grades is provided to meet varying demands.
Novaprene TP compounds from Schäfer Polymer GmbH (Seevetal, Germany) are a suitable alternative for plasticized PVC and certain crosslinked polymers. The compounds offer high resistance, easy processability, and excellent mechanical properties. "Novaprene compounds can be processed like thermoplastics in all usual processes like injection moulding, extrusion, and injection blow moulding," says Dethlef Klein, the company's sales manager.
Klein says Schäfer develops the compounds according to a company's specifications, and common uses for the product include drop chambers, tubing, and gaskets.
Chomerics
Suited to encapsulating electronic medical devices, a flexible, thermally conductive form-in-place silicone elastomer from Chomerics (Marlow, Bucks, UK) offers high thermal conductivity, while minimizing stress on the component being cooled.
Chomerics application engineer Gerry Young says the compound is designed for manufacturers who "want a high-performing material at a low cost." Therm-a-form T646 thermal interface compound eliminates the need for a conventional moulded sheet when cooling multiheight components and conforms to irregular shapes without compressive force to ensure that all gaps are filled. "The compound is ideal because it is so soft," says Young. "It doesn't put stress on the component."
Supplied as a kit containing silicone binder and aluminium oxide filler liquid as reactive components, the compound's typical cure time is three minutes at 150°C or one hour at 60°C. It can be supplied in 45-, 177-, and 200-cm3 kit sizes for use with manual or pneumatic dispensing systems.
Icotec
Composite flow moulding is a new net-shape production technique for thermoplastic composite materials, especially implants. The process, developed by Icotec (Rebstein, Switzerland), allows for the use of highly reinforced materials with the option of custom-made mechanical properties and the incorporation of nonmagnetic, metallic x-ray markers.
"It's a one-shot, one-part process that can produce components four to five times better than PEEK," says Sümer Sertel, marketing and sales manager at Icotec. The process uses a thermoplastic matrix of PEEK and a crossbinding fibre that's glass, metallic, or whatever the application requires.
The processing of the high-fibre content results in superior fatigue resistance. "The technique lends itself to not only fastening elements, but also structural components such as bone plates," says Sertel.
Purac
A complete line of lactide and glycolide monomers and copolymers can be widely varied to meet customer requirements. Purac (Gorinchem, Netherlands) specializes in the custom synthesis of copolymers with specific compositions and inherent viscosities. "The main feature is the biodegradability. The length of time can range from a couple of weeks to a couple of years, depending on the application," says Mart Eenink, Purac biomaterials business unit manager.
Purasorb products are used as starting materials for a wide range of biodegradable medical and pharmaceutical products. One of the most common applications is as wound care products because the polymers provide high mechanical strength with biodegradibility and biocompatibility.
The products are also used for surgical implant devices. Due to their biodegradability, they can also eliminate the need for additional removal surgery. Applications include orthopaedic bone fracture fixation devices and sports medicine implants.
Eenik says the company is working on expanding its product line, and touts Purac's longevity in the biomaterials industry as a benefit to its customers. "As a supplier of raw materials, we have to have a commitment to the long term," says Eenink. "We have a long history in the industry." Purasorb materials are manufactured according to GMPs, and each production batch is analyzed according to standard analytical procedures.
Victrex plc
A powder coating provides
a cost-efficient means of enhancing part performance, even in small-volume production
runs. PEEK-Coat from Victrex plc (Thornton Cleveleys, Lancs, UK) can reduce
the amount of polymer used to produce the part as compared with other processing
techniques.
Keith Gostelow, product development manager for PEEK-Coat, explains, "When a thin layer of high-build PEEK polymer coating is applied to a substrate, it confers all the properties of PEEK polymer to that application and helps retain the structural benefit of the substrate."
The powder coating offers the same properties as the PEEK polymer, including high temperature resistance, the retention of mechanical performance at high temperature, high wear and abrasion resistance, and good performance in a wide range of chemical and radiation environments. "Because these properties are achieved without the use of additives," continues Gostelow, "PEEK polymer is an inherently pure polymer with low levels of extractable ionic species, which makes it suitable for analytical and medical applications."
Atoglas
A range of specialty acrylic moulding plastics has been developed to provide a combination of performance properties that are essential to the medical and diagnostic devices. The Oroglas line from Atoglas (Bernouvillea, France) has high optical clarity and biocompatibility, including blood contact.
Other properties of the plastics include excellent sterilizability, flexible PVC compatibility, processability, dimensional stability, bondability, and UV-transmittence. The Oroglas impact series offers seven to ten times the impact resistance of standard acrylics.
The Oroglas SG-7 and SG-10 are the newest additions to the company's product line and exhibit no yellowing or discolouration after 5 megarads of gamma radiation sterilization. A team of process engineers is available to assist customers in selecting the optimal product for specific applications.
Eastman Chemical Co.
The
Ecdel elastomers from Eastman Chemical Co. (Kingsport, TN, USA) are clear, tough
copolymers that can be injection moulded, blow moulded, or extruded into film
or sheet. "The elastomer remains remarkably clear and free of the blush or haze
that can occur in high-temperature autoclaving necessary for medical applications,"
says Clark Parker, communications representative at Eastman.
Ecdel elastomers combine the chemical resistance, toughness, autoclavability, and inertness of polyesters with flexibility over a broad temperature range. "It's ideal for applications in pharmaceutical packaging, where low extractables and toughness in harsh environments are required," says Parker.
Copyright ©2001 European Medical Device Manufacturer
