Contamination control packaging choice is no simple matter
10/01/2007
Selecting the right packaging solution for your product requires close collaboration with your package provider
By Michael D. Fisher, Fisher Container Corp.
What is your use and application? This is the first question a prospective customer should be prepared to answer when trying to determine the type of packaging material best suited for a current or new application/packaging project.
It sounds simple, but be careful, because “use and application” are loaded terms. Don’t forget that from a packaging perspective use and application encompass everything from the fill process all the way to final disposal of the packaging.
Also consider the old packaging adage, “A package is only as good as its shipping container.” There exist hundreds if not thousands of combinations of film types, co-extrusions, laminations, and compounds to enhance a material’s capabilities as well as whole families of adhesives used to customize the proper material for a specific product’s use and application. So be prepared to answer even more questions (see “Considerations for cleanroom packaging”).
There are quite a few other potential concerns as well, but let’s stop here and discuss some of these factors in more detail.
Material film type and density
Material density selection is based on each customer’s needs and specifications. For example, customers may specify a particular film type or gauge to best suit their own internal packaging and handling requirements prior to shipment. As a result, while one customer may specify a particular density because they have semiautomatic packaging machinery applications that need a film type with a low coefficient of friction for stackability, another may require just the opposite for speed and handling.
Film and gauge choices can be very confusing, and customers, especially those in the cleanroom industry, should be sure that their source has a wide range of knowledge concerning film performance capabilities at all levels. For example, a provider should be able to cite the film’s machinability; packing speeds that can be obtained by utilizing manual, automatic, and semiautomatic equipment; stackability; particle generation; outgassing, leachables, and extractables; clarity; MVTR; OTR; gloss; haze; puncture strength; elongation; seal integrity; dart impact, and so on. Everything is customized to address the needs and concerns of each individual customer even though two products may be exactly the same.
As an example, consider the cleanroom laundry industry. In the U.S., there are five major players in this industry and all five use one of the following three film types for a variety of reasons: low density, high density, and, on occasion, medium density polyethylene. Some use a combination of these materials while others strictly adhere to one type.
Since the cleanroom laundry industry’s products are generally soft in nature, the film choice can be one that doesn’t require a great deal of strength in comparison to packaging a medical device or a rigid product. The need to avoid pin-holing is an important requirement that can be achieved by simply choosing the proper gauge along with the proper material and sealing equipment. Clarity issues are important to some and not so to others. Sometimes this is determined by the customer’s clients or it’s just a matter of personal preference and aesthetics. Reading UPC codes through a cleanroom package can be the sole reason for high-clarity requirements.
Sterile presentation
Packaging that allows sterile presentation or peel can also be complicated and requires a great deal of expertise to properly choose and recommend the appropriate materials.
For example, prior to prescribing packaging materials for sterile products, it is essential to know what type of sterilization method will be applied to the package. Those most commonly used today are autoclaving/steam, dry heat, gamma/electron beam, ethylene oxide (ETO), and atomized peroxide/vapor. Whatever package type is prescribed must exceed the aggressive demands of the sterilization method.
Ease of opening is another essential film performance. One common material with a wide range of uses is DuPont’s Tyvek®. Tyvek® to Tyvek®, as well as Tyvek® sealed to other support films, allows it to be peeled back for sterile presentation.
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Tyvek® comes in several grades; prescribing the proper grade is essential. Tyvek sealed to polypropylene is a standard for many of the more aggressive sterilization methods. For the less aggressive, Tyvek® sealed to high density polyethylene can be used as well.
Film variations are geared toward end use and application, as well as the protection requirements of the product. Since this is largely determined by how the product is going to be shipped and then handled by the end user, it is often advisable for a customer to obtain a variety of sample packages from the provider for their own in-house and/or field testing.
Pouches
Pouch packages come in a vast variety of shapes and film combinations. These include four-wall, bottom-gusset, side-gusset, chevron, zippered pouches, K-pouches, flat pouches, header, shaped, and stand-up, to name just a few. Customers should take into consideration the variety of types that their sources are capable of providing to be sure that they are being offered the best possible solution for their product.
 High density film bags are ideal for packaging clean garments such as gloves, hoods, boots, and masks. Photo courtesy of Fisher Container Corp. |
Pouches are generally used for applications that require a more aggressive seal and containment. The variety of monolayer, co-extruded, and laminated films are endless. Some types commonly used for cleanroom applications include foil polyethylene, polypropylene, PET, EVOH, nylon, metalocene enhanced structures, opaque films, and Tyvek®. Some applications even use eight-layered, co-extruded structures laminated to various support films. Suppliers need to have extensive expertise about how each film type will perform in conjunction with adhesives and other film types in order to successfully combine them.
Customers have a number of barrier requirements for their pouch packages. For example, a product that is light sensitive must naturally use a film that contains a UV inhibitor. Alternatively, a structure can be laminated to the film to prohibit any UV contamination.
Pharmaceutical manufacturers, in particular, are one group of customers that requires very aggressive oxygen and moisture protection to ensure their products will achieve the required shelf life. There are a number of laminated structures suitable for holding in moisture or to keep it out. Alternatively, customers can go straight to the “flexible-can” material-foil.
Oxygen can be the ultimate killer of a product, and there are a number of monolayer structures that can inhibit it. Again, there are also usually other considerations; it’s a matter of making an educated choice. Quite often, package clarity issues also come into play; if so, this eliminates the use of foil laminates or metallized structures. In these cases, EVOH co-extruded material is often the best choice since it inhibits oxygen but still allows you to see the product. In other cases, it may be easier to add pigment to obtain a translucent or opaque structure rather than going into laminations or co-extruded material to successfully meet a customer’s need.
Information is key
As always, the best source of information for prescribing the optimum solution for a particular product is the customer. The more information the customer can provide the package provider about the unique characteristics and requirements of the product, the better.
As easy as this may sound, it can sometimes be difficult depending upon what stage of development the product is in. For example, when a product or application is in an early developmental stage, it may be difficult to provide as much detail as the supplier needs about the possible use and requirements of the product in order to prescribe the best material or materials the first time out of the box. In these cases, as a minimum requirement, customers should expect their suppliers to insist on comprehensive and aggressive field and shelf-life testing using proven testing methodologies. In the end, the critical information this testing provides will save the customer valuable product, time, and money.
Michael D. Fisher is president of Fisher Container Corp., based in Buffalo Grove, IL (www.fishercontainer.com).