Presidential Green Chemistry Challenge: 2006 Small Business Award
NuPro Technologies, Inc. (now Eastman Kodak)
Environmentally Safe Solvents and Reclamation in the Flexographic Printing Industry
Innovation and Benefits: Flexographic printing is used in a wide array of print jobs such as food wrappers and boxes, but the process uses millions of gallons of solvents each year. Arkon and NuPro developed a safer chemical processing system that reduces the amounts of solvents needed for printing. The new system eliminates hazardous solvents, reduces explosion potential and emissions during solvent recycling, and increases worker safety in the flexographic printing industry.
Summary of Technology: Flexographic printing is used on everything from food wrappers to secondary containers such as cereal boxes to shipping cartons. The photopolymerizable material on a flexographic printing plate cross-links when exposed to light and captures an image. After exposure, flexographic printing plates are immersed in a solvent to remove the unpolymerized material. The developing, or washout, solvent is typically a mixture of chloro, saturated cyclic, or acyclic hydrocarbons. Xylene is the most common solvent. Most traditional washout solvents are hazardous air pollutants (HAPs) subject to stringent reporting requirements; they also raise worker safety issues and create problems with recycling and disposal. North America alone uses 2 million gallons of washout solvents each year with a market value of $20 million. Many small printing plants use these solvents.
Together, Arkon Consultants and NuPro Technologies have developed a safer chemical processing system, including washout solvents and reclamation/recycling machinery for the flexographic printing industry. NuPro/Arkon have developed several new classes of washout solvents with methyl esters, terpene derivatives, and highly substituted cyclic hydrocarbons. The advantages include higher flash points and lower toxicity, which reduce explosion potential, worker exposure, and regulatory reporting. The methyl esters and terpene derivatives are biodegradable and can be manufactured from renewable sources. All of their solvents are designed to be recycled in their Cold Reclaim SystemTM. In contrast to traditional vacuum distillation, this combination of filtration and centrifugation lowers exposures, decreases maintenance, and reduces waste. The waste is a solid, nonhazardous polymeric material.
In the U.S. market, NuPro/Arkon are currently selling washout solvents that are terpene ether- and ester-based or made with low-hazard cyclics. They are marketing their methyl ester-based solvent in China and Japan. Their first filtration-based Cold Recovery SystemTM is currently in use in Menesha, WI and is being marketed to larger U.S. users. Their centrifugation reclamation system for smaller users is in the final stages of development.
Use of these solvents and systems benefits both human health and the environment by lowering exposure to hazardous materials, reducing explosion potential, reducing emissions, and, in the case of the terpene and methyl ester-based solvents, using renewable resources. These solvents and the reclamation equipment represent major innovations in the safety of handling, exposure, and recovery. The reduced explosion potential, reduced emissions, decreased worker exposure, and reduced transport and maintenance costs translate into decreased cost and improved safety in all aspects of flexographic printing processes.