There's no single magic bullet when it comes to determining what plastic resin is most suitable for a particular product or packaging application.
We began to develop a comprehensive program seven years ago because not one single technology is suitable for all applications, said Roman Forowycz, group president and chief marketing officer at Clear Lam Packaging Inc. in Elk Grove, Calif.
We have three mutually exclusive approaches in our Project EarthClear program, he said.
Each approach renewable raw materials, packaging with recycled content, and lightweighting is designed to reduce the impact of the package on the environment, he said.
David Clark, sustainability director for Amcor Rigid Plastics in Ann Arbor, Mich., agreed.We try to use a system approach to packaging development, looking at the next generation of materials and the increased use of recycled materials where it is available, Clark said at the Sustainable Plastics Packaging 2010 conference, held Dec. 8-9 in Atlanta and organized by Plastics News Global Group.
In March, Amcor PET Packaging changed its name to Amcor Rigid Plastics after corporate parent Amcor Ltd. of Melbourne, Australia, acquired parts of Alcan Packaging and moved into materials beyond PET and into other processes such as extrusion blow molding.
It has given us the opportunity to look at the environmental impact of different materials and which is best for a particular need, he said. Amcor, for example, has developed for sliced fruit sold under the Libby's brand by Seneca Foods Corp. a 24-ounce round and a 26-ounce square PP container that is 80 percent lighter than glass and has a higher thermal stability than heat-set barrier PET.
Similarly, Clear Lam developed new containers made of PLA resin for Stonyfield Farms' multipack yogurt cups. 'We wanted to move into the renewable area and felt we needed to find a suitable partner, said Forowycz, whose firm makes flexible films, rigid roll stock and thermoformed containers. We felt that this was a transformational technology for the next decade.
Marketing for the yogurt cups focuses on their being made from renewable, plant-based polylactic acid resin, and touts better barrier properties, a lower carbon footprint and the use of less energy to produce them because of lower melting temperatures for PLA.
The decision was made not to talk about recycling and composting because we don't [compost] in the United States [or recycle] except for PET and HDPE containers, Forowycz said. We don't advertise those points because it would convey a benefit that doesn't exist.
As firms mull material changes to improve the sustainability of packaging, they must also look at equipment and processes.
To change technologies, you need to understand the current process and the limits of the existing equipment, he said. It is difficult to change a mindset and say there is a new way to do this, as it requires changes in operating processes.
Bill Goldfarb, president of Universal Dynamics Inc. in Woodbridge, Va., which makes equipment for blending, drying, granu- lating and the like, emphasized the importance of working with fabricators to understand how to process materials like PLA.
There are challenges in processing and reprocessing PLA bioresins, and advantages and disadvantages, Goldfarb said.
But, he emphasized, the changes needed to switch from PET to PLA are simple, such as proper drying temperatures, lower melt temperatures and removing contaminating traces of PET.
The disadvantages, for now, are application limitations from a temperature and durability standpoint, and slight modifications of existing equipment, Goldfarb said. PLA also requires dehumidifying hopper dryers with low-temperature process options.
There is a handling/processing paradigm shift ... and there is a learning curve whether it is extruded or whether you do injection molding. You need a new mindset, but the capital equipment costs will be the same or less than when you run PET, he said.