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Flexo Sustainable : End of Year 2008
sustainability goals for itself, and has also established goals for its supply base. Among its target metrics are several that will impact the packaging and flexo industries. They are: • Reduce packaging across its supply chain 5 percent by 2013. • Reduce solid waste by 25 percent. •Have 20 percent of its supply base aligned with sustainable products. To emphasize the importance of sustainability, Wal-Mart has stated that this will be an ongoing high priority for the company. This has garnered a significant amount of industry attention and has created a large amount of concern among Wal-Mart’s suppliers, particularly as to how this may change the relationship they have built with this important customer. WalMart has the leverage to push this agenda through the industry in a way that other companies cannot. The retail giant has created a scorecard it will use to evaluate sustainability and has asked its suppliers to begin loading detailed information related to each SKU. Each package will be assessed and graded. The scorecard criteria are weighted, emphasizing various issues that impact sustainability. From the supplied information, a score will be generated and your packaging will be ranked and compared to other packaging. Needless to say, the packaging, with the highest sustainability and lowest cost, will be identified as the preferred product. It is safe to say this has caused everyone to scramble. In many cases, the information has not been readily available to complete the scorecard data entry. So, a great deal of data is being collected. The consumer products companies are completing the data entry on their SKUs. Although printers do not provide data directly to the scorecard, printers are asking their suppliers for help and support. In fact, the ink industry has received inquiries related to sustainability of inks; as well as general questions on sustainability. Wal-Mart is not including inks, coatings, and adhesives in this initial round of activity. Inks, coatings and adhesives are not part of the scorecard. Wal-Mart personnel have stated this at several conferences. What about Inks? There are many different forms of inks (i.e. paste, liquid). For the purpose of this article we will focus on the liquid form which is used for flexo printing. Within flexo printing there are several different types of liquid inks available; solventbased, water-based, and radiation-cured (UV and EB). But, flexo inks can be further broken down by chemistry. Within each type of flexo ink there may be a number of different chemistries used, each having its own unique sustainability characteristics. The chemistry chosen for any one application may have less to do with the choice of the Figure 2. Figure 1. Wal-Mart’s Scorecard Weightings •15% - green house gas emissions •15% - material value •15% - product to package ratio •15% - cube utilization for transport •10% - transportation •10% - recycle content •10% - recovery value • 5% - renewable energy usage • 5% - innovation printer than the requirements of the job. Each chemistry delivers a specific set of performance characteristics. The decision to choose an ink, and its specific performance characteristics, typically is made based on the printer’s need to balance performance, cost and environmental compliance. Often the choice comes down to performance. To meet the performance requirements a printer may have a very limited choice of ink systems. So choosing an ink often comes down to the selection of an ink that meets the performance requirements on the press, and its end-use performance in the distribution chain. The market has, in most cases, moved to water-based inks, where they have the capability to meet the performance requirements. An example is grocery sacks. All grocery sacks are printed with waterbased inks. But, bread bags, although they may seem similar, can not be printed with water-based inks. Bread bags have an entirely different set of performance requirements. All bread bags are printed with solvent-based inks. All inks are made up of four classes of materials; pigments, res- in, solvent, and additives (Figure 2). The pigment is the color portion of the formula. Pigments are solid particles. The resin is also a solid, and binds the pigment to the substrate and provides many of the end-use performance requirements. The solvent reduces the formula to a liquid form, allowing the ink to be printed by the flexographic printing process, and modifies the drying rate of the ink. And finally, additives are a wide variety of materials which modify the physical properties of the ink to improve its use on the press, and/or its end-use performance. These additives could be slip aids, defoamers, etc. Most of the materials in all of these classes are petroleum-based products. These are highly refined, and processed specialty chemical materials which deliver very unique qualities to the formulas to which they are added. There are some ink raw materials which come from renewable resource feedstocks. However, all pigments used in flexo inks come from non-renewable resources. Some are organic, some are inorganic (Figure 3), but all come from a depletable feedstock. In the resin class we have nitrocellulose and polyamide resins, Flexo Ink Components Additives Solvents Resins Pigment where some of their feedstock is derived from cellulose and crude tall oil (pine trees). Nitrocellulose and polyamide are used in solvent based inks and make up the largest volume of resins used in solvent-based flexo inks. In water-based inks we have protein resins and shellac, although very little shellac is used these days. Proteinbased resins are based on casein (milk) or soy protein (soy beans). Ink suppliers receive many inquires about soy inks. Most inquires regarding soy-based inks are generated because a significant amount of soy oil is used in litho (paste) inks. People incorrectly assume soy oil can be used in all inks. Vegetable-based oils work well in litho ink, but can not be used in flexo inks. www. f le xomag.com Year end 2008 Sustainable FLEXO 9