Materials Flex to Device Packager Needs
New flexible packaging options are being explored and developed to meet the demands of device manufacturers.
Erik Swain, Senior Editor
While there are still plenty of standard flexible packages being requested by medical device manufacturers, flexible packaging suppliers are noticing an upturn in the desire for more exotic materials, especially those that can produce a higher barrier.
An increase in devices that require special moisture or oxygen protection is the main driver behind the greater use of barrier materials. The predominant barrier material that device manufacturers request is foil, which offers a total barrier provided its integrity is not compromised. But there are other options as well.
HIGH-BARRIER FILMS AND FOILS
"We are getting more requests for foils and for 'clear foils,' which are high-barrier films that you can see through," says Geoff Pavey, senior product and process development engineer, Oliver Products Co. (Grand Rapids, MI). "There is also interest in silica-coated films and metallized films to achieve better barrier properties. Puncture-resistant materials also continue to draw interest. These tend to have Surlyn as a core material, but a nylon base can provide an extra amount of puncture resistance if needed."
There are several reasons why high-barrier clear films are becoming more desirable, says Jack Cunneen, vice president of LPS Industries (Moonachie, NJ). "Some products have an indicator strip that shows whether the integrity of the product has been compromised, and others have desiccant cards," he says. "For those, visibility is an issue. And some manufacturers just want their product to be seen."
"Finding clear materials that approximate the barrier of foil is a big deal because they can eliminate layers of packaging," adds John Ozcomert, director of technology for Rexam Medical Packaging Americas (Mundelein, IL). "If you can see the product, you can often avoid having to apply a label as you would on a foil structure, or remove the need for printed packaging. Another example is blood bags, which are often put in a polypropylene (PP) wrapper and then into a foil pouch for steam sterilization purposes. Because of the anticoagulants in the assembly, a high barrier must be maintained. If you can replace a PP pouch with a clear, high-barrier material, the foil becomes unnecessary."
Rapid assay (instant) diagnosis tests are one product area that is driving the need for high-barrier packaging films, Cunneen says. "The self-administered dipstick tests are a rapidly growing marketplace and require a good barrier for moisture integrity, but also require durability and cost-effectiveness in their packaging," he says.
|Tolas's proprietary heat-seal coatings provide clean, easy peelability and visible adhesive transfer for assurance of package integrity.|
Other areas where these materials draw interest, says Carl Marotta, president of Tolas Health Care Packaging (Feasterville, PA), are "implantable devices that are sensitive to moisture or oxygen, devices such as intraocular lenses that have to be packaged in a liquid environment and need to keep the moisture in, and absorbable sutures, which are made from polymers that can't come into contact with moisture."
One problem, however, Marotta says, is that "with a lot of high-barrier packaging, you have to tear or cut the package open, which goes against the grain of what medical packagers look for today, which is something easy to open and dispense in an aseptic environment. It is difficult to balance peel characteristics with strength and barrier characteristics, especially when polymers are laminated with foil."
THE COST TRADEOFF
With more-specialized needs such as barrier protection comes increased cost, which is not always what device manufacturers want to hear. But in the more productive relationships, suppliers and device makers are working together to figure out how to keep total system costs down, even if the cost for a particular material must rise.
The tradeoff a device manufacturer is willing to accept between cost and performance is "a complex formula unique to each company," notes Curt Larsen, consultant for DuPont Medical Packaging (Wilmington, DE), which makes Tyvek brand protective materials. "But in general, the tighter the margin on the product, the more they will pay attention to costs."
A few years ago, a series of new downgauged materials was introduced, and the use of the metallocene-catalyzed process for films became a more popular method of downgauging flexible medical packaging. But now more solutions are needed. "Downgauging has pretty much already been done where it can be done," Pavey says. "The big buzzword is still 'metallocene,' but most don't understand what that entails. It refers to the catalyst and method of processing films, not necessarily to a film in and of itself. You can have a wide variety of materials that are produced using a metallocene-catalyzed process. It is sometimes a challenge to make device manufacturers consider what it means to their applications."
"The initial wave was to cut material costs only," Ozcomert notes. "Now the trend is to look at ways in which the total cost can be reduced." For example, he adds, using a strong primary package and less secondary packaging, or giving a device maker an early sense of what the puncture strength will be on the corners of the package based on their tooling are ways to reduce total costs.
|The FlexForm B formable web from Rollprint provides puncture resistance with a uniform draw, allowing for downgauging of the standard bottom web film.|
To this end, Rollprint Packaging Products (Addison, IL) introduced its FlexForm B formable web as a potential cost-effective alternative to traditional webs. According to the firm, FlexForm B is tough and puncture resistant with a uniform draw. As a result, downgauging the standard bottom web film is possible in many applications, and it offers cost advantages on a gauge-to-gauge basis over traditional webs.
Hearing about cost concerns from packaging engineers and device manufacturers has led paper manufacturer Kimberly-Clark Corp. (Roswell, GA) to "focus product development on simplifying manufacturing," says Karen H. Bean, technical paper research and development. "This has guided us to develop a paper that seals directly to a variety of multilayer films. The new paper, Impervon, seeks to drive down raw-material costs for packagers, while delivering the performance they have come to expect from reinforced papers."
Offering a stable of versatile materials can also help reduce costs, Cunneen says. "We try to tailor requests to our existing applications, so we don't wind up with a multitude of products," he says. "The key is to establish a select group of laminates. We have a half-dozen major structures and can tailor 85% of requests into one of them. When you can do that, your service improves dramatically, and it certainly allows you to remain cost-effective."
Cost is most likely to be a serious consideration in high-volume form-fill-seal applications, Marotta says, but better materials can actually save money there, too. "When you're forming a bottom web and stretching it, you want to be sure that you are retaining as much of the original barrier as possible as it is stretched into a thinner layer," he says. "This comes back to the material itself. If you build it with good extensibility and the ability to remain pinhole-free, that will help to reduce costs in the long run."
As a result, research and development efforts are underway to uncover new technologies that can make the flexible packaging process better and more cost-efficient. One area of inquiry relates to form-fill-seal equipment.
"We are seeing more movement toward film to film on the part of device manufacturers in an effort to reduce material costs," says John Merritt, managing director of machinery supplier Tiromat Medical Packaging (Avon, MA). "Film top webs do create a challenge for packaging machinery. Many films inherently have a lot of stretch, and machinery manufacturers must develop systems that accommodate this stretch."
He notes that Tiromat has developed a device designed to minimize the impact of stretching of the top web associated with machine indexing. "The bottom web is held in place with clips that minimize tension associated with indexing," he says. "The challenge is the top web, which is pulled through the machinery without clips. Every time the machine indexes, there is stress on the bottom cross seal of the package. This stress can result in seal disruption. Films are getting thinner and thinner, and the thinner they get, the more this becomes an issue."
"This is an example of how the more sophisticated the machinery becomes, the more sophisticated the materials that can be used must become, and the more sophisticated materials become, the more sophisticated the machinery must become," Merritt says.
Cunneen agrees that there has to be a synergy. "The new machines are extremely fast, and you can't stay in business if your material slows the machine down," he says. "You have to find ways to keep them compatible."
Flexible packagers are sure to have more options at their disposal soon. For example, Topas, a cyclic olefin copolymer (COC) from Ticona (Summit, NJ), is being evaluated for possible use in flexible medical packaging. It is already being used in pharmaceutical blister packaging. "COCs are the kind of resin-based barrier material that could work for medical applications, and not just in the pharmaceutical marketplace," Ozcomert says.
Modified-atmosphere packaging systems, which use inert-gas technologies instead of vacuum chambers to keep oxygen out, could also come to fore in the future, but so far the technology has caught on in the food industry more than the medical industry, Marotta says.
Larsen notes that "constant research is being done by converters on adhesives, and a few new ones have come out of experiments on heat-sealing Tyvek to flexible materials."
A new lidding technology from a new supplier to the medical packaging field, Bomarko Medical Packaging (Plymouth, IN), might also offer a new range of options to flexible packagers.
"We produce in excess of 85% of the finger-bandage paper consumed in the United States, which demands many of the same quality standards used in lidstock for devices, especially in the area of sterility guarantee," says Kimball Mancke, president and COO. "These include precise, exact amounts of coating, consistent and clean peel, a uniform seal that guarantees sterility, breathability, and a print surface that enables clean graphics. But we have better functionality and yield, which leads to cost savings. Our goal is to remove overengineering and therefore cost by offering technically innovative materials properly matched to the device manufacturer's need. In some instances, such as devices that are very expensive or have extremely sharp edges, the package is not overengineered. But in many instances, suppliers have preyed upon the conservative nature of the medical device manufacturing industry and have not suggested structures that would do the job and reduce cost."
In fact, Mancke says, "we felt there was a need for a new look at the entire segment. Everyone has migrated into the same group of structures, and there is really no differentiation. We are developing papers that are significantly different in yield, barrier, and peelability. We are trying to give people a fresh look at alternative packaging without sacrificing quality. Our minds are not locked in by history in this market, and we have no alliances with any existing structures, so we are free to develop structures that reduce costs and provide acceptable functionality. We don't have to forget what we know in order to improve."
Other technologies are a little farther off. Polymer blends containing additives that can "scrub" oxygen or water from a package are seeing increased application; and the concept of a self-sterilizing package represents an extension of this technology, Ozcomert notes. But regardless of what special needs a device manufacturer might require for its flexible packaging, new options are being explored and developed every day.