Single-use syringes, cannulas – and beyond

Be it contact lenses, intubation tubes, single-use syringes or cannulas, more than half of all medical products manufactured around the world are made of plastics. But even beyond these mass-produced articles, the prospects for polymer materials in medical technology look rosy. Market experts had the opportunity to track both the advances made and the growth of plastics in medical applications at K 2013. Subsequent to the market analysis some examples from K 2013 will follow.

Plastics are increasingly used in medical applications. (photo: Messe Düsseldorf)

Of the roughly 47 million tonnes of plastics processed in Europe, almost 40% are used for packagings, 21% for civil engineering and construction, 8.3% in the automotive industry, and 5.4% in the electrical and electronics industry. The rest is spread across such diverse areas as sport and leisure, toys, household goods, furniture, agricultural uses and medical technology. Regarding the latter, no exact percentages are available because of the blurred distinctions as to where medical technology starts and ends. But one thing is clear: only the technically sophisticated and high-quality plastic grades find their way into health care applications.

With a growth rate approaching 9% in 2010 and 6% in 2011, medical technology lies substantially above the figures for most domestic industries in Germany. Turnover by German enterprises in this market has been estimated at approximately €21billion for 2011 by Spectaris, the German industry association of businesses in the optical, medical and mechatronic technologies.

Plastics were already being used in medical technology even before synthetics began to write their commercial success story from the mid-20^th century onwards. In 1936, William Feinbloom made the first contact lenses in the USA from polymethyl methacrylate (PMMA). From the mid-20^th century, plastics were also being used increasingly to make artificial limbs. Currently, sophisticated composite constructions made of plastics reinforced with carbon fibres (CFRP) are being used to make such unusual prostheses.

Expectations are high on plastics for use in medical technology – and the demands are growing further. Novel creations in polymer chemistry, for instance, improved silicone elastomers, thermoplastics with antimicrobial finishes and the opportunities offered by nanotechnology are expanding the variety of applications, and more.

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PVDF copolymer for minimally invasive medical catheters

Arkema introduced Kynar Rx 752 polyvinylidene fluoride (PVDF) copolymer for use in minimally invasive medical catheters that are exposed to bodily fluids for less than 30 days. The Kynar Rx 752 fluoropolymer was specifically developed for medical catheter applications and is readily melt processed using standard extrusion or injection moulding equipment similar to those used to process polyethylene (PE), polyvinylidene chloride (PVC) or polypropylene (PP). This allows for continuous coextrusion of multilayer constructions used in advanced catheter shaft designs.  Additionally, Kynar Rx copolymer tubes and moulded components can be welded together using radio frequency (RF), direct heat contact, and ultrasonic methods to create consolidated catheter components.

Kynar Rx 752 copolymer is USP Class VI compliant and exhibits good resistance to chemicals and temperatures. This allows medical device components made from the material to be chemical, autoclave or irradiation sterilised.  The material offers a flexural modulus of 50,000psi (345MPa) and dynamic coefficient of friction of 0.54, according to ASTM test methods. The new medical grade copolymer can be coextruded into multilayer tubing, providing device companies with an alternative to manually assembled shafts with PTFE liners.

Medical catheter application (photo: Arkema)

Medical tubing extrusion

Milacron Extrusion Systems showcased the Cincinnati Milacron PAK250 – 63.5mm single screw medical extruder along with the Multi Pass Tank specifically designed for medical extrusion. The most common product produced by this machine is flexible PVC for non-phthalate plasticisers.