PFFC - October 2008 - (Page 50)

TECHNICAL REPORT UV/EB INKS The views and opinions expressed in Technical Reports are those of the author(s), not those of the editors of PFFC. Please address comments to the author(s). Structures Higher profits lie in printing non-traditional jobs such as shrinkwrap and laminated packaging, leading converters to use UV or EB presses in laminated structures. By James E. Goodrich, Sartomer Co. Stronger Figure 1. A Laminate Structure In Which the White Ink Is Printed on the Substrate Laminate Laminating Adhesive Color Ink Layer Substrate White Ink Layer Figure 2. A Laminate Structure in Which the Color Layer Is Reverse Printed onto the Substrate Substrate Color Ink Layer White Ink Layer Laminate Laminating Adhesive Figure 3. Laminate Structure Used in This Study Melinex 813 UV Laminating Adhesive Cyan UV Flexo Ink Layer Melinex 813 ltraviolet/electron beam (UV/EB) technology continues to infiltrate the established graphics markets and create new markets as well. Traditionally, UV/EB inks were used in surface printing jobs in which the properties of the cured UV/EB inks led to improvements in solvent and abrasion resistance over solvent and water-based inks. The UV/EB inks also worked well with the UV/EB coatings used in the packaging structure. Now converters are using UV/EB printing presses in new, more profitable areas, including laminated packaging structures. The idea of using UV/EB inks inside a laminate structure is new. Higher profits can be made in printing shrinkwrap and laminated packaging. The interaction between UV/EB ink, whether it is flexographic or lithographic, and the substrate is well defined. Also understood is the interaction between the cured UV/EB inks and the various coatings. In a laminate structure, different interactions occur, and different forces are introduced that affect ink performance. Within a laminate structure, several different layers must work in concert. Starting at the bottom of Figure 1, the substrate—usually polyethylene terephthalate (PET), oriented polypropylene, polyethylene, or a metallized film—acts as a surface to accept the printing. It also acts as a functional barrier between the ink layers and the packaged goods. The functional barrier can prevent migration of species, especially organic materials, water, oxygen, and nitrogen. In this structure, white ink acts as an opaque backing so the true colors are visible or to hide what is within the packaging. The white ink must have excellent adhesion to the printed substrate. On top of the white ink, the colored imaged area is printed. With an alternative structure (Figure 2), the image is reverse printed and backed with a white ink. Both laminate structures are widely seen. The color ink layer must provide good intercoat adhesion to both the white ink layer below and the laminating adhesive on top. A laminating adhesive is applied between the color ink layer and the substrate. The adhesive must have excellent adhesion to the color ink layer and to the laminate (or second substrate) that is put on top. WWW.PFFC-ONLINE.COM U 50 | OCTOBER 2008 http://www.pffc-online.com

Table of Contents Feed for the Digital Edition of PFFC - October 2008

PFFC - October 2008 Contents First Glance Calendar of Events From the Editor Web Lines Process Management News Clips Narrow Web & Label Reporter Narrow Web & Label What's New Products Shrink Sleeves Carton & Box Reporter Carton & Box What's New Products Cover Story - Custom Coating Core Shafts Show Preview Flexo Printing Film Converting Static Control UV/EB Inks What's New Products Trade Show in Print Services Directory Classified Marketplace Equipment Buyers & Sellers Advertisers Index Experience Speaks

PFFC - October 2008

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