Feature

Medical Marvels

With an ageing population requiring ever more healthcare treatment, medical OEMs are looking for total solutions from their molding partners. Using some of the latest medical grade engineering resins oughta keep 'em happy.


Print this page

April 1, 2013 by Mark Stephen, editor

For plastics processors, there may be no such thing as a recession-proof sector — but medical parts molding comes damn close. At the very least, the medical molding business is less susceptible to economic swings than most other industries. Take an ageing population of baby boomers, add life-prolonging advancements in medical technology, and throw in the fact that — because of the red tape involved in meeting FDA regulations and rigorous product approval processes — OEMs are reluctant to take contracts away from approved molders to recertify replacements, and you’re looking at a sweet deal for the processors.

WHAT THE DOCTORS ORDERED 

High growth product areas in the field include drug delivery systems for respiratory care and diabetes, such as dry powder inhalers, prefilled syringes, and improved blood-glucose test strips. Although hospitals will continue to be the strongest area for injection molded disposable medical supplies, molders can expect to see strong opportunities in over-the-counter products, as consumers chose to treat themselves to lessen out-of-pocket medical costs.

But there are difficulties, as well. Medical OEMs are looking for total solutions from their molding partners in areas such as part and tool design, prototyping, and part qualifications/validations. Some molders are investing more resources into research and product development, believing that new products will define the future of the medical supply business — and they’re probably not wrong. Competition is also ramping up as more international molders enter the market. Finally, medical molders are also feeling pressure from hospitals to lengthen the life of their products; some hospitals spend as much as $1 million a year on incineration, so the heat is on processors to engineer and produce parts that can withstand the myriad of sterilization procedures used throughout the world.

According to market research firm The Freedonia Group, engineering resins accounted for an estimated 22 per cent of total material consumption for medical parts in North America last year. And the smart money is on demand for engineering resins to expand due to the need for higher performing materials in diagnostic testing, drug delivery systems, preventive medicine, and surgical instruments. Commodity resins certainly have their places, but if a product molder is looking to really make a mark in the medical device market, engineering resins might just be the best way. Here’s a look at some recent offerings. 

FIGHTING INFECTION

A new product portfolio from SABIC Innovative Plastics is designed to help reduce hospital-acquired infections, which — according to a 2011 report by the World Health Organization — played a role in killing 99,000 patients and clinicians in the U.S. alone in 2002. The portfolio comprises nine different antimicrobial grades across four product families, including Lexan EXL copolymer, Lexan polycarbonate (PC) resin, Xenoy PC/polybutylene terephthalate (PBT) resin, and polypropylene (PP) resins with and without fibreglass reinforcement. The antimicrobial compounds featuring silver technology have been tested for log reduction values — the level of microbes eliminated from a surface — according to the ISO 22196-2007 protocol. 

According to SABIC, five of the new grades have a high antimicrobial effect (log reduction value above 4, representing a 99.99+ per cent reduction in pathogens) and four grades have a low antimicrobial effect (log reduction value below 4, representing a 99.0-99.99 per cent reduction in pathogens). “These options allow customers to select the appropriate formulation depending on whether the end product is a high- or low-touch application,” said David Wildgoose, general manager of SABIC’s engineering resins division. “Potential applications include fluid and drug delivery applications, surgical instruments, monitoring and imaging devices, and durable medical equipment such as hospital beds and operating tables.”

BASF is also offering new engineering resins designed to prevent dangerous microbial buildup on medical device and equipment surfaces. The company’s HyGentic antimicrobial product line includes HyGentic SBC, a transparent injection moldable styrene butadiene block copolymer granulate material that contains antimicrobial silver ions; and HyGentic PA, an antimicrobial glass fibre reinforced, injection moldable polyamide granulate that can be used directly to manufacture medical devices such as inhalers or ventilation filters. “These materials are exceptional in being extremely effective against a range of fungi and bacteria,” said Edgar Eichholz, BASF’s business development manager for medical device materials. “Additionally, all medical devices produced with HyGentic products can be disinfected by conventional procedures.”

BASF also recently made available Ultradur B4520 PRO, its first PBT for injection molded medical applications. “Ultradur B4520 PRO improves the high dimensional stability of PBT by adding optimized shrinkage behaviour to meet the stricter requirements for reproducible dimensional accuracy made on components intended for medical devices,” said Vinny Sirani, BASF’s business manager for high performance plastics. “This material can be easily printed on and sterilized with ionizing gamma radiation or ethylene oxide.”

DOWN THE TUBES 

Many polymers used in minimally invasive surgical devices are hydrophobic and create friction against moist bodily tissue — not a good thing. Hydrophilic coatings are often applied to these polymer components to reduce friction and avoid tissue trauma, but these add additional manufacturing steps and may provide more lubricity than necessary — again, not good.

In response to the problem, Arkema’s new hydrophilic Pebax MV 1074 SA 01 MED polyamide is said to absorb up to 48 per cent of moisture from the surrounding environment, and to form hydrogen bonds that create a wet film on the component surface that enhance lubricity against bodily tissue. With a 40 Shore D hardness and 80 MPa (11,600 psi) flexural modulus, Pebax MV 1074 SA 01 MED has been designed for co-extrusion applications, and can be extruded as a hydrophilic polymer layer in a multi-layer tube or film extrusion for surfaces coming in direct contact with bodily tissue that require high moisture absorption, such as surgical tubing.

Also new from Arkema, and also for medical tubing and angioplasty balloon applications in which “pushability,” burst pressure properties, and elongation are the goals, are Rilsan MED polyamide 11 and Rilsamid MED polyamide 12. The Rilsan polyamides can be used in either extrusion or injection molding applications, Arkema said. 

TPE TECHNOLOGY

For such applications as grips for medical and dental utensils and knobs and buttons for medical equipment — products that healthcare workers don’t want to go all butterfingers on — the newly expanded CLR series thermoplastic elastomers (TPEs) from Elastocon TPE Technologies Inc. are available in low oil formulations. Developed for applications that require oil- or plasticizer-free and non-blooming high strength properties, the expanded grades now include a broader range of hardnesses, Elastocon said, from 15 Shore A to 75 Shore A. Two grades — CLR65 and CLR75 — are completely oil-free. The formulations are designed to stand out from among competitive clear TPEs in that they’re odorless, can be extruded or injection molded, utilize materials that are FDA compliant, have superior tear resistance, and can be easily color tinted. Selected grades can be overmolded onto polypropylene. 

Star Thermoplastics also has some new TPE offerings meant to give medical parts molders new, lower cost alternatives for incorporating
or switching TPEs in the design and processing stages. The StarMediflex grades are offered from a soft 8 Shore A to a harder 60 Shore D, and meet FDA and medical grade requirements. Suggested applications range from physical therapy straps and medical pads to PVC replacement tubing applications that can be injection molded or extruded, the company said. 

Don’t confuse those with the company’s new StarMed TPEs, offered in clear or translucent grades, and described as easy to color, non-allergenic and customizable, and with a rubbery feel that can replace latex or silicone. Further, all grades are said to be recyclable. 

Finally, Star’s new StarPrene TPEs are intended to mold and perform better than TPVs, offering similar flow characteristics with the same rheology, but at a more competitive price. High flow versions available that are designed to be easier to color and to provide more consistent colors than TPVs, the company said. StarPrene materials are also described as offering superior tensile strength and elongation, without the need to dry the material before processing.

RESOURCE LIST

Arkema Canada Inc. (Bécancour, Que.);
www.arkema-inc.com; 819-294-9965
  (Burlington, Ont.); 800-567-5726

BASF Canada (Mississauga, Ont.);
www.basf.ca; 866-485-2273

E.I. DuPont Company (Mississauga, Ont.);
www.plastics.dupont.com; 905-821-5193

Elastocon TPE Technologies Inc. (Rochester, Ill.); www.elastocontpe.com; 888-644-8732

SABIC Innovative Plastics (Toronto);
www.sabic-ip.com; 800-323-3783

Star Thermoplastics (Broadview, Ill.);
www.starthermoplastics.com; 708-343-1100