New Choices in Flexible Packaging
High-performance alternatives are available for companies willing to make the switch.
Cost-effective peelable sealants, new alternatives in barrier materials, and pouch production choices are just some of the factors that come to bear as companies weigh their options in flexible packaging.
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Packagers are driven to new materials for new products, but packaging can change with demand for new material properties and cost-savings imperatives.
“The material choices relate to customer preference, what they are packaging, and the potential risk of fiber tear [from uncoated Tyvek],” says Mike Oberkirch, marketing and operations director for pouches and bags, Amcor Flexibles (Mundelein, IL).
“In many cases, it’s all volume driven. Companies with large volumes will produce packages from rollstock on a Multivac or Tiromat [form-fill-seal (FFS)] machine, taking out a lot of labor costs. If the volume declines, you will potentially see them switch to preformed pouches or bags. Devices ramping up in volume will convert from preforms to rollstock. Customers’ approaches are constantly turning over,” Oberkirch says.
Material preferences can change as firms change pouch sourcing and production, such as for peelable seals. Amcor offers its Core-Peel extrusion-coated peelable films as an alternative for making peelable pouches.
Vendors’ peelable film solutions such as Core-Peel and Allegro from Rollprint Packaging Products (Addison, IL) offer multiple advantages for certain requirements and in some applications. These include wider sealing windows and fewer variations in seal strength compared with uncoated or traditional heat-seal-coated (HSC) materials. By failing cohesively and peeling from themselves, they eliminate fiber tear that can occur when uncoated Tyvek is sealed to standard poly films or particle lift when coated Tyvek is used.
Peelable sealants created by extrusion coating have provided the most cost-effective peelable heat-seal technology. The process requires fewer manufacturing steps as, in this process, resins are cast directly onto a web. Less-expensive resins replace films that incorporate sealants, and HSC solutions. And processing can be two or three times faster than with films requiring adhesive lamination, according to Rollprint Packaging Products.
“In premade pouches, more than 80% of the market uses uncoated Tyvek sealed to standard polyester/ polyethylene laminates or extrusions. You are working with a narrower sealing window, so you have to be cautious with temperature, pressure, and dwell to limit seal-strength variations,” Oberkirch explains.
“The peelable films are doing well in rollstock applications where you are packaging large volumes at high speeds. You can slap a lot of heat onto the web to ensure a good seal, but because the peel system is in the inner layer, it will peel consistently,” Oberkirch adds. “Thus far, it doesn’t appear that peelable films have been widely accepted for premade Tyvek pouches. While the added cost is minor, it’s the cost of validating a new package that prevents the inroads for many of these new materials,” he says.
Rollprint’s extrusion-coated Allegro B and Allegro T sealants feature two different seal strengths for sealing to film-to-film (Allegro B) and to uncoated paper and uncoated Tyvek (Allegro T).
“The Allegro sealants support a very wide operating window, with a bright seal indicator when you peel it,” says Dhuanne Dodrill, president, Rollprint. “Allegro sealants are much easier to validate because of their processing advantages.”
“With Allegro B, in many cases, we are competing with coextruded or blown-film laminates. Extrusion coating provides a significant cost savings,” she adds.
Oliver Medical (Grand Rapids, MI) manufactures coatings for hot-melt HSC film, foil, and Tyvek. “Some clients prefer HSC materials; others, extrusion-coated peelable films that we will source for them,” says Jeff Murak, director of sales and marketing, Oliver Products.
Film makers and converters report unceasing new demand for barrier materials, largely owing to crossover devices incorporating active drugs.
“High-barrier pouch applications have increased dramatically over the past year, specifically in applications using aluminum oxide coatings and foil,” says Murak.
Tapemark (West St. Paul, MN) designs, manufactures, and packages devices such as wound-care dressings and transdermal patches that incorporate active pharmaceuticals. The contract manufacturer makes medical device components and converts materials for disposable devices and drug delivery in convenient single-dose forms that support compliance.
“Our customers are always looking for unique packaging ideas,” says Steve Larson, Tapemark’s medical pharmaceutical business manager. “The most critical components are the barrier properties and the shelf life provided for the product. The materials we use vary quite a bit based on the active ingredients’ sensitivity to light, moisture, and oxygen. The other factor is child resistance. A straight peel pouch isn’t going to work. You need a weld seal. We have developed child-resistant bend-and-tear designs where adults can read the directions to open the package.”
Barrier is typically achieved with foil laminates using a low-density polyethylene layer for sealing. “Foil laminates are the workhorse here, providing protection for a variety of actives. Feedback from our customers is that Aclar is too expensive in some market situations. We used to use Tyvek, but it became too costprohibitive,” he says.
Tapemark’s customers often performs stability testing on several materials to provide alternatives in cases where supply is interrupted or there are exorbitant price increases. “You have very little flexibility in making a packaging change after you have validated your materials. We go into stability with several options with appropriate materials from more than one vendor. This provides more flexibility on cost and delivery, and you have more chance of passing stability,” Larsen says.
Ampac Flexibles (Chicago) has tested Honeywell’s Aclar Flex for use in a flexible package for dispensing an OTC liquid cold remedy. The package would replace a foil laminate rigid package. The formable bottom web comprises a 75-gauge nylon layer, 15-micron Aclar Flex, and 2-ml LDPE sealant layer, says Jeff Uhrig, technical director. “We have found Aclar Flex to be an excellent product, with easy forming characteristics,” says Uhrig.
Yet Aclar’s price remains an obstacle in high-barrier flexible packaging applications, according to many converters. “Aclar has great barrier and clarity properties. We have seen it used most often as an overwrap for solution bags where clients want a clear material with the same barrier properties as foil,” says Bob Liesenfelt, business development director, coated and laminated products, Amcor Flexibles.
“We are not using Aclar Flex commercially at this time. Our ClearFoil line provides a broad range of barrier properties and prices,” says Rollprint’s Dodrill. “People want the product to be visible. With ClearFoil, they can obtain barrier properties that approach and in some cases exceed that of Aclar Flex, with tremendous flex resistance without degradation of barrier properties.”
Ampac Flexibles has emphasized solventless adhesives to provide low chemical residuals in high-barrier foil laminates produced on a Comexi laminator. For medical applications, it offers the peelable Flexi 6883 (PET/PE) for sealing to its Flexi 6884 (PET/foil/PE) for use on a Doyen Medipharm four-side-seal machine. The company has launched Flexi 6864, a thick-gauged foil laminate for packaging of heavy devices and kits. The high-barrier lid stock seals to materials including Barex, APET, CPET, HDPE, PVC, and polypropylene. It is engineered to overcome delamination issues inherent in similar structures, says Doug Andersen, account manager, Ampac Flexibles.
Packagers have sought to address cost in some cases by moving to film-to-film pouches.
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“If you don’t have to use EtO, and you can move to gamma, you can reduce total package cost by eliminating the Tyvek. We have customers using Tyvek in gamma and E-beam applications that are considering changing to an all-film structure,” says Dodrill.
Extrusion-coated PropaPeel peelable sealants can be used for film-to-film sealing or as bottom webs for sealing to uncoated paper for autoclaving. This application avoids stringiness after autoclaving, and “many products that stick to coated papers during steam sterilization do not adhere to PropaPeel,” Dodrill says.
CLP Packaging Solutions Inc. (Fairfield, NJ) helped one client move to a film-to-film pouch using its “easy-peeling” polyester/polyethylene laminate film. Peelable additives are mixed in with the polyethylene layer when the film is extruded.
A cardiovascular device maker was switching from EtO to gamma sterilization to reduce packaging costs, cut sterilization cycle time, and eliminate the health hazard of residual EtO, says Mike Barr, account manager, CLP.
A paper/poly/poly easy-peel film replaced coated Tyvek, sealed to an EVA/Surlyn formable web. “They found in initial testing that the seals were bursting in air transit because of air trapped inside the packages,” says Barr. A vacuum system was installed on the Multivac unit to take out most of the air as the films were being sealed, he explains.
For cost savings in products requiring EtO sterilization, some CLP clients are testing laminated lidding material with Tyvek patches. CLP is testing the in-line patch production from Tiromat Medical Packaging FFS machines using the TiroBreathe system. The Tyvek material unwinds at a right angle to the lidding material for creating small vent windows.
Tyvek Asuron is DuPont’s only medical-grade Tyvek that is manufactured and supplied from two separate locations—one in Richmond, VA, and another in Luxembourg. The value of Tyvek Asuron’s dual-fulfillment locations was highlighted by hurricane Katrina. “Dual sourcing has become an issue for some customers that want to make sure they have multiple sources of product,” says Wanita Hlavaty, product development engineer, DuPont Medical and Industrial Packaging.
Tyvek Asuron also provides advantages in appearance, seal performance, and printability compared with Tyvek 1073B. “We were able to increase our rating to verifiable B-grade bar codes for printing with methods including flexo and thermal transfer. In small-font and variable-printing applications, font edges will be less fuzzy and the print easier to read,” she says.
ASURON TACKLES TRANSPARENCY
Tyvek Asuron demonstrates improved seal appearance at higher sealing temperatures. “As you increase sealing temperatures, the L-color reading (the measure of transparentization) stays much more level with Tyvek Asuron than with Tyvek 1073B. Tyvek Asuron runs from the 90 range to the 80 range. Tyvek 1073B starts dropping off dramatically from an L color in the mid- to high 80s to the 35–40 range,” says Hlavaty.
In one-year and three-year accelerated aging after sterilization with various methods, Tyvek Asuron and Tyvek 1073B exhibit similar performance as bacterial barriers. The logarithmic reduction value (LRV) is almost identical based on sterilization or aging. “We are still developing seal-curve understanding. But our testing shows that Tyvek Asuron seals similarly to Tyvek 1073B in most applications,” she says.
Hlavaty says that DuPont “expects adoption of Tyvek Asuron to be relatively slow as it is used for new product packaging. Most people are not going to revalidate their packaging unless they have an issue with improved printability or transparentization.”
“We have seen more customer concern about sourcing after last year’s hurricanes. People want to make sure they can get their materials,” says Dodrill.
“Tyvek Asuron has performed very well in our testing, and we have made our customers aware of the fact that it is available, she adds.
Liesenfelt says that Amcor has validated Tyvek Asuron for sealing to other webs and supplies it coated and uncoated for FFS applications. “Customers will have to prove properties such as puncture resistance and microbial barrier in applicational use,” he says.