Technical achievements in flexible packaging were dominant among the winners in the '94 Flexible Packaging Assn. packaging competition. The winners were announced during FPA's annual convention in early March in Naples FL. As good as they were it's also safe to say they were unusual-not the kind of applications that are likely to inspire many followers. Easily the most unusual is a three-side-sealed pouch made from a silicon-oxide coated polyester laminate (1). Such "glass-coated" films have attracted considerable attention in recent years for their ability to combine high barrier properties with clarity. But they're expensive so the number of applications have remained somewhat limited. The pouch is used to hold blocks of cesium iodide crystal for an experiment in particle physics at Fermi National Accelerator Laboratory Batavia IL. Fermi's pouches are made by Proven Design (Palmyra NY). The pouch material called Clearfoil® is supplied by Rollprint (Addison IL) which won the award. It buys SiOx-coated polyester and laminates it to a layer of heat-seal material. Total thickness is 3.5 mils. According to Fermi's Ron Ray the blocks come in two sizes: 1" x 1" x 20" and 2" x 2" x 20". They're produced in France Japan and the U.S. but the sheer number of blocks Fermi needs for this particular experiment 3 in all make it impossible for the suppliers to deliver them fast enough. So for the past three years Fermi has been building an inventory of the blocks as fast as the suppliers can make them. Come November there will finally be enough blocks to begin the experiment. The reason they're being stored in pouches of ClearFoil is that they're highly hygroscopic. The ClearFoil material reduces water vapor transmission rates to less than 0.02 g/100 sq "/24 hours. Also included in each pouch is a moisture level indicator that turns red if moisture becomes a problem. Here's where the clarity of the ClearFoil material comes in. If the material was not clear the indicator would be useless.