Many organizations struggle with the best approach to designing complex film structures for flexible packaging. Complex structures are required because there is no single polymer or material that is ideal for all situations; one must combine the best properties of several materials in order to provide an optimized structure for each packaging situation.
Just as there are numerous tools and methods for solving quality issues, there are also many methodologies for the design process. One such method for designing an optimum flexible packaging structure entails four steps: Identify, Design, Optimize, and Verify. Most flexible packaging converting companies will have expert packaging professionals who are skilled in this process and can provide assistance.
The first step is to identify the packaging issues, define the problem and summarize the package objectives. What are the critical characteristics that the flexible packaging film structure must provide? The most common demands are for packaging structures that deliver barrier properties to protect the contents from oxygen, water vapor, light, or aroma transmission. Frequently, there are special requirements for use on high-speed packaging lines where the flexible packaging film must provide sealing properties tailored to a particular packaging line. Is the packaging environment difficult to manage? For example, a plant producing and packaging roofing shingles has severely high temperatures and dust exposures which can make sealing of the package difficult. Does the flexible packaging need to hold aggressive compounds that could degrade the packaging over time? All of these parameters must be documented and the appropriate materials selected to address each.
Once all of these critical factors are identified, the design phase begins with the selection of materials that address each parameter. As substrates with the desired properties are selected, the designer must determine the best method of assembling the various and sometimes incompatible material layers. There are multiple lamination techniques for joining the substrate layers. Also available are combination substrates, which achieve unique properties through the coextrusion of films with multiple, distinct polymer layers.
After the material layers have been defined, the designer must optimize the structure so that it can be produced with the manufacturing equipment available. The converting operation will have specific equipment available within their manufacturing base. If a particular lamination method is not available internally, then the converter may need to outsource that portion of the packaging film assembly to a subcontractor. For example, the best lamination method might be extrusion lamination and the converter only has adhesive based lamination available.
This is also the stage where the costs of materials and converting are evaluated and alternatives are identified. The proposed packaging film structure must be within the original parameters established with regards to price, availability, and any other constraints as defined by the customer. If the customer requirements are satisfied, the process is ready to move into the trial and testing phase.
In the last phase, the converter needs to verify the design by actually producing some trial materials. These will become the flexible packaging samples used to determine if the design criteria established in the first steps are satisfied. The converter and the customer will perform qualification testing (shelf life, barrier, sealing, etc.) as well as accelerated aging and any other fitness for use tests as defined by the customer. It is also time to test the film structure on the customers packaging lines. Again, a set of acceptance parameters are defined to provide evidence that the packaging film functions within the established packaging equipment performance criteria. Once these steps are complete, it will be time to move into larger size trials followed by the scale-up and commercialization mode.
The development process outlined above may seem simple, but there are many potential pitfalls and areas where adverse situations could occur. This is the primary reason that AWT provides access to seasoned flexible packaging experts who can guide customers through the development process to yield optimum results in the shortest possible time frame. Contact Us to get started.