Plasma Treating for Energy Curing InksDec 17th, 2008 | By Mark Plantier | Category: Field Applications, Plastics
Energy curing technologies have evolved from infancy in the 1960s and have been in a maturing phase since the 1990s. Improvements in raw materials and a better understanding of the energy curing process made a substantial impact on ink-performance characteristics and have led to increasing acceptance of the technology among printers. Energy-cured inks and coatings have re-emerged to the forefront of printing technologies as printers become increasingly interested in increased production speed, improved product properties, enhanced resistance to chemicals such as solvents or cleaners, enhanced quality, lower applied cost, cool curing on heat sensitive substrates, reduced energy requirements, less waste, and reduced space requirements.
Estimates of actual market size vary considerably. Essentially, the graphic arts portion of energy curing is about US$ 500 million, which includes inks, coatings, and adhesives. In the narrow-web segment, ultraviolet (UV) light curing represents 25 percent of the total market, including flexo, letterpress, offset, and screen. Electron beam (EB) curing is an instantaneous on/off technology and comprises about 9 to 12 percent of the energy market. Growth of EB curing is slower, primarily due to the considerable capital costs involved in starting up with EB technology. These costs have dropped considerably in the past few years, but they remain higher than UV.
Assisting the re-emergence of energy curing technologies is the evolution of atmospheric plasmas as a key surface preparation protocol prior to applying UV and EB inks and coatings for web, sheet and 3D surface applications. Since atmospheric glow plasmas feature a low temperature, homogenous, uniform and high density discharge at material surfaces, removal of low molecular weight organics along with a cross-linking effect initiated by free radicals effectively increase the adhesion of energy-curables composed of resin, pigment/additives, and monomers. This is because free radicals connect with the molecules of the resins and monomers, and they, in turn, cross-link with each other, forming chains of molecules we recognize as the “cured” ink/coating film. Atmospheric plasma surface treatment systems are gaining rapid acceptance among printers over the past five years because they match printer’s productivity and reduced waste objectives, and because they offer printers the ability to print/coat a wider range of materials to expand market opportunities.
View the whole technical paper entitled “Energy Curing Of Substrates and Inks with Atmospheric Plasma” to learn more about plasma treating for energy curing inks.
Rory Wolf, Enercon Industries Corporation, Menomonee Falls, Wisconsin, USA
Amelia Sparavigna, Dipartimento di Fisica, Politecnico di Torino, Torino, Italy