Use of an electron beam to cure inks, laquer, paint, adhesives, resins, composites, and for crosslinking of polymers.
Electron beam (E-beam) curing uses high energy electrons in controlled doses to polymerize and cross-link polymer materials. Curing of composites can take place at ambient temperature. E-beam curing is a well-established technology -- first applied to processing wire insulation in the 1950's -- that is now being applied to an ever wider range of products. The technology is environmentally friendly as it reduces the use of solvents, offers energy savings benefits, and eliminates cooling station requirements. Curing time and plant sizes are reduced. Paints, epoxy-based resins, powder coatings, and composites with reactive accelerators are being developed that are suitable for electron beam curing. Some products claim excellent mechanical properties, better scratch resistance, low void content, color stability, and higher gloss. Curing can take place in reduced oxygen environments
Traditional thermal curing often requires a dryer or autoclave, requiring long cure times, high energy consumption, and often producing toxic by-products. Residual stresses are created in the materials, sometimes requiring finishing or tooling. E-beam processing has expanded to include curing of laminates, composites, leather finishes, heat-shrinkable plastics, fiber-reinforced resin coatings, thermosetting composites, vulcanized pressure-sensitive adhesives, cross-linking of binding agents for magnetic materials, semiconductor enhancement, and flexible packaging often used in food processing.
Use of electron beam curing methods to cure specially formulated inks can reduce energy consumption by over 50% when compared to conventional convection ovens and significantly reduce emissions and explosion concerns. The U.S. EPA cites energy savings of 75% to 90%. Eight independent studies have shown savings of 25% to 65% to curing costs of manufacturing. Solvent emissions are also greatly reduced. Savings are especially good for complex shaped components often used in engines and military vehicles, and aerospace applications. Because the process occurs at ambient temperatures, molding materials can be made of low cost materials such as wood or foams.
Status:
Baseline Description: Autoclave Curing of Polymer Matrix Baseline Energy Use: 616000 kWh per year per unit
Use of a 10 MeV electron beam instead of an autoclave with a four-hour cure cycle for polymer matrix composite (PMC) materials reduced curing energy use from 1.76 kWh/kg to only 0.22 kWh/kg (Source: E-Beam Services, "Electron-Beam Curing of Polymeric Composites As An Enabling Technology for Advanced Manufacturing". The U.S. EPA cites energy savings of 75% to 90% ("Ultraviolet and Electron Beam (UV/EB) Cured Coatings, Inks, and Adhesives). The baseline annual energy use is estimated by assuming that 5 cure cycles per day are run, with 350 days/year of operation, and that each cycle involves 200 kg of polymer matrix composite material material.
"Typical" Savings: 88% Energy Savings Reliability: 4 - Extensive Assessment
Energy Use of an Emerging Technology is based upon the following algorithm. Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
Simple payback, new construction (years): N/A
Simple payback, retrofit (years): N/A
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
B Laurell, 09/22/2003. Industrial Application of Electron Beam Curing in the Field of Coatings Electron Crosslinking AB
Robert Norris, 01/14/2000. Electron Beam Curing of Composites Overview SAE Technical Paper
T. Lund, 08/17/2009. New Developments of Electron Beam Accelerators RadTech Europe 2009
Sayaka Uchida, 03/12/2008. Utility and Advantages of Electron Beam Curing in Flexible Packaging San Jose State University
E-Beam Services, 05/10/1999. Electron-Beam Curing of Polymeric Composites as an Enabling Technology for Advanced Manufacturing International Composites Expo '99
ECW, 01/01/2000. Ultraviolet and Electron Beam Curing Energy Center of Wisconsin
Clean Energy Technology Center, 07/01/2001. Ultraviolet and Electron Beam (UV/EB) Cured Coatings, Inks and Adhesives U.S. EPA , Technical Bulletin