PFFC - October 2008 - (Page 52)

UV/EB INKS the adhesive to the substrate through covalent bonds. The next part of the project looked at the resistance of all of the different cured inks to different monomers commonly found in UV laminating adhesives. See Table III. Effects on Resistance Table III. Effect of the Six Different Monomers on the Cured UV Flexo Inks Resistance TMCHA SR833S SR492 CN131B CN120Z CNUVE151 IR NE NEA NEA I EOEOEA IR NE IR I IR THFA IR NE IR NEA IR PEA IR NE IR I I TDA IR NE I I I IBOA IR NE I NEA NEA A drop of each monomer was placed CN991 NE NE NE NE NE NE onto the printed and cured area of CN994 I I I I I I the different cyan UV flexo inks. CN9893 NE NEA IR IR NE NEA The drop of monomer was allowed to sit on the sample for 15 minutes at CN2262 NEA I I I NE NEA room temperature (nominally 23 deg PRO6196 NE I I I NE NE C). After 15 minutes, the drop was CN293 NE NE NE NE NEA NEA wiped off, and the result was noted. CN386US NEA NEA NEA NE NEA NE As expected, CN131B, CN9893, CN710, and CN820 had low crossCN549 NE NE NE NE NE NE linking and were susceptible to attack CN710 IR IR IR IR NE IR from the aggressive monomers. The ink CN820 I I I I I I was either removed or showed dramatic effects from the monomers. NE = No Effect; NEA = No Effect Ink Absorbed; I = Intermediate Effect; IR = Ink Removal Samples SR833S, CN120Z, CNUVE151, CN994, and CN9893 had good resistance to the iso- As manager of graphic arts, James Goodrich is responsible propyl alcohol double rubs but were affected by the test monomers. for the support and development of UV-cure printing ink Interestingly, all five of the materials had two acrylate groups per products and technology at Sartomer Co., Exton, PA. He molecule, hence low cross-linking, and the monomers could penpreviously held positions as graphic arts specialist and etrate the cured ink film. The CN994 showed minimal effect from associate development chemist at Sartomer. Goodrich holds the monomers. a bachelor’s degree in chemistry with a minor in polymer Samples SR492, CN2262, PRO6196, and CN293 had acry- science from Pennsylvania State Univ., State College, PA. He can be reached at 610-363-4100. late functionality higher than two acrylates per molecule and performed well. Apparently, the additional cross-linking from the higher functionality increased the monomer resistance. uSupplier Infot Also interesting was the effect of amine compounds on uSartomer Co. | www.sartomer.com monomer resistance. Despite being lower acrylate functional, PFFC-ASAP 360 CN386US showed good resistance to the monomers. The uDuPont Teijin Films | www.dupontteijinfilms.com higher acrylate functional and amine functional CN549 PFFC-ASAP 361 showed excellent resistance to the monomers. Both of these uHarperScientific | www.harperimage.com/harperscientific.asp materials owe their excellent monomer resistance to additional PFFC-ASAP 362 surface curing due to Norrish Type-II photoinitiator reactions. uFusion UV Systems | www.fusionuv.com Peel Strength PFFC-ASAP 363 Finally, to pull together all of the other testing, the inks were incorporated into a laminate structure. Remember, the cyan UV flexo inks were printed onto Melinex 813. After the inks were cured, the laminating adhesive was applied and nipped between the printed Melinex 813 layer and an unprinted sheet of Melinex 813. The entire structure was cured using a Fusion 600 W/in. D lamp at 100% power for an integrated energy of 625 mJ/cm2 on an International Light IL390 radiometer. The cured samples were cut into 1-in. strips, then tested for peel strength on an Instron tensile tester. The adhesive thickness was 10–13 µm. A thicker adhesive film was chosen to achieve higher Tpeel strengths that could show differences between the inks. By changing the monomer or oligomer chemistry incorporated into a UV flexo ink, lamination properties can be dramatically affected. Ink adhesion to the printed substrate, the Tg of the monomer or oligomers used, and the resistance of the cured ink to aggressive monomers in the UV laminating adhesive are all key parameters in the strength of the laminate structure. 52 | OCTOBER 2008 uInternational Light Technologies | www.intl-lighttech.com PFFC-ASAP 364 uBrookfield Engineering | www.brookfieldengineering.com PFFC-ASAP 365 uInstron | www.instron.us PFFC-ASAP 366 References Painter, P.C. and Coleman, M.M. Fundamentals of Polymer Science, 2nd ed. Lancaster PA: Technomic Publishing Co. Inc., 1997. Smith, Deborah A. “UV Curable Laminating Adhesives.” Sartomer Co. Inc. 2003, www.sartomer.com/TechLit/5050.pdf Petrie, Edward M. “Adhesive Laminating of Films.” SpecialChem for Adhesives. Oct. 5, 2005, www.specialchem4adhesives.com/resources/articles/article.aspx?id=1338 Editor’s note: This paper was originally presented at RadTech 2008. WWW.PFFC-ONLINE.COM http://www.sartomer.com http://www.dupontteijinfilms.com http://www.harperimage.com/harperscientific.asp http://www.fusionuv.com http://www.intl-lighttech.com http://www.brookfieldengineering.com http://www.instron.us http://www.sartomer.com/TechLit/5050.pdf http://www.pffc-online.com

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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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