Sealant injects quality for devices

New, peelable coextruded polyester sealant for sterile medical packs of Taut’s catheters boosts package performance, improves seal appearance.

Lauren R. Hartman, Senior Editor

Packagers of retail products aren’t the only ones with a keen appreciation for small packaging changes that produce vastly improved results. For Taut, Inc., package and product sterility are a must. The sterile medical device manufacturer in Geneva, IL, prides itself on producing top-quality medical devices for use in surgery that are distributed throughout the U.S. and in more than 20 other countries.

Since the 1970s, Taut’s unique approach to product design, manufacturing technology, medical device innovation and product marketing has generated a variety of medical products, including a leading line of cholangiogram devices. Cholangiography is a procedure in which a thin catheter is inserted through the abdominal wall, and into the gallbladder to detect the presence of gallstones. The catheters are used with a contrast media (dye) that’s injected through the catheter into the human body so that anatomical structures can be visualized and certain abnormalities, such as gallstones, can be detected on an x-ray.

While its medical device packs must ensure sterility, Taut was concerned recently with the performance and appearance of unit packs for some of the operative catheters as well as for a line of capillary drains used to facilitate draining of body fluids. Last year, Taut decided to revise the hermetically sealed packs with a new coextruded peelable sealant called Allegro® T from Rollprint Packaging Products that produced winning results. The new chevron-sealed packs comprise top and bottom webs both produced by Rollprint from rollstock in cut sealing widths with a base web of 48-ga oriented polyester, extrusion-coated with Allegro T proprietary easy-peel sealant and a top web of uncoated Tyvek® 1073-B, a 7.3-mil spunbonded, nonwoven high-density polyethylene from DuPont. Taut uses Circle Packaging Machinery systems to package the instruments.

The filled, sealed packs are then loaded in counts of 10 (cholangiogram catheters) or 20 (capillary drains) into cartons.

Drawing on peel technology that provides visual verification of seal integrity, the Allegro T sealant produces a bright white border in the seal area of the package where the bond has been broken after the substrates are peeled away. How does it work? Allegro produces what’s called “a cohesive failure” when peeled away from another substrate. The act of peeling away the substrates causes the sealant to split from itself. Because some of the sealant remains bonded to the Tyvek lidding and some remains bonded to the bottom film web, this provides a visible white seal transfer. The catheter packages measure approximately 21/2 in. wide and are 205/8 in. long, while the capillary drain packs measure 21/2 in. wide by about 12 in. long.

The previous packaging for the cholangiogram catheters was also produced from rollstock consisting of a top web of Tyvek that was heat-seal-coated with a vinyl acetate and surface-printed in blue ink. The base web comprised 48-ga polyester laminated to 2 mils PE. While the package performed well and ensured the sterility of the devices by ethylene oxide, Taut experienced troubles with an ingredient in the ink that interacted with the coating while the materials were in rollform. Although not visible when the coated Tyvek was inspected, a heat-seal transfer phenomenon could result.

Taut says that occasionally, after the packages were sealed, the coating transfer was inconsistent in the seal area, when the coexsealant Tyvek lidstock was peeled open, creating a reverse image of the printing in the seal area. While seal integrity was not affected, a less than desirable appearance could have potentially prompted hospital personnel to question whether the package’s sterility was compromised. What’s more, the previous vinyl acetate coating tended to yellow over time, Taut says. Since the devices have a five-year shelf life, that wouldn’t help the quality image of the products.

Packaged similarly to the catheters, the capillary drains featured a top web of uncoated Tyvek that was heat-sealed to the same type of polyester/PE clear film base web as for the catheter package. Uncoated Tyvek lidstock was used because it was more compatible with the medical drain products, because coated versions tended to stick to the medical device. But the uncoated Tyvek didn’t leave the bright white seal transfer that demonstrates visual verification of seal integrity, and there were some issues with fiber tear, says Raul Brizuela, vp of sales and marketing for Taut.

“In an operating room environment, the particulate matter floating around the room has to be minimized as much as possible. Occasionally, the packages experienced minor fiber tear when peeled open, and though it’s completely inert, we want our packaging to look as high quality as possible. That’s no longer an issue.” Package integrity issues being unacceptable by Taut’s standards are quickly corrected, notes Brizuela. “One thing we discuss continuously is the image of our company. Everything centers on producing the highest-quality products.” He says the packages for both the catheters and the capillary drains were quickly re-evaluated.

Eliminating ink reveal

Rollprint’s Allegro T coex sealant formulation impressed Ron Kenseth, Taut’s vp of operations. The sealant technology proved it could provide a cohesive split on the sealant layer that gives it consistent seal and peel strength, a wider operating window and the bright white seal indicator.

It was at that time that Taut moved to the new package structures, each made with an uncoated Tyvek top web and a clear-film base web of Rollprint’s finished material, designated RPP #21-1148, which includes 48-ga polyester coextrusion-coated with 2-mils of the Allegro T sealant. The results eliminated all of the problems. Available in several grades and in PE-and polyester-based formulations, the sealants are designed to seal at moderate temperatures across a wide sealing temperature window (an estimated ±25 deg F, versus 5 deg F associated with the previous coating). Rollprint says the Allegro sealants are also engineered to maintain integrity through a wide gamut of temperatures from freezing to high-heat pasteurization temperatures and to retort sterilization process temperatures of up to 260 deg F. Coextrudable onto polyester, nylon, foil, paper and other substrates, depending on end-use requirements, Allegro T is also notable for its barriers to moisture, is suitable for radiation sterilization and when peeled has a look and feel of a seal made with a coated product. Taut was thus able to address the aesthetics of the coating transfer and inhibit the yellowing effect with the catheter packs and eliminate any fiber tear on the drain packages.

The new packs have the premium look of a coated Tyvek product without the cost or the tacking issues. Importantly, the cholangiogram packages’ appearance indicates that product sterility hasn’t been compromised. The results worked well for both the catheter and the capillary drain packaging, Brizuela adds. “The white seal appearance is critical, because if it’s not there, the sterility of the device can be questioned.” Sums up Kenseth, “This new package opened up our production criteria. We can set up our equipment under a bigger sealing-tolerance window, we’ve eliminated fiber tear, and our packaging is no longer susceptible to yellowing.”

More information is available: Peelable sealant, lidstock, basestock: Rollprint Packaging Products, 630/628-1700. Tyvek material: DuPont Tyvek, 800/448-9835. Sealing equipment: Circle Packaging Machinery, Inc., 920/983-3420. Allegro® is a registered trademark of Rollprint Packaging Products, Inc. DuPont™ Tyvek® is a registered trademark of DuPont.

Exp. 9-30-04 Reprinted from Packaging Digest, September 12, 2003, by RSiCopyright. Copyright © Reed Business Information, a division of Reed Elsevier, Inc. All rights reserved. For reorders call RSiCopyright at 651.582.3800. For subscription information call 1-800-662-7776.