Student Research Wins Award: Laura Schultz

FRSC student Laura Schultz receiving her first place award at the Lawter lecture series.

Laura Schultz (Class of 2023) interned at INX in the summer of 2022.  They were invited to submit a paper on their project to the Lawter Lecture Series competition. Laura was awarded first prize at the National Association of Printing Ink Manufacturers (NAPIM) 2022 Fall Technical Conference! 

Congratulations Laura! Details of her work are below.

Title: Quantifying and Qualifying Risks Associated with Photoinitators in Ink

Abstract: Regulatory reclassifications continue to make it necessary for UV ink manufacturers to reformulate and improve ink formulations. Reclassification of UV material as a substance of very high concern (SVHC) by European Chemicals Agency (ECHA) triggers changes in regulatory reporting in addition to requiring manufactures and imports to notify customers if the content is greater than 0.1% by weight.   In addition to changes in reporting, these regulatory updates become the forefront of investigation to determine actual risk.  The current study aims to determine quantity of unreacted photoinitiator as a function of cure time. This work is an extension of previous research correlating unreacted PI as a function of curing passes.

In this study, cured ink samples were extracted for residual photoinitiators (PI).  The PIs were quantified on an Agilent 1290 HPLC /Agilent 6460 Triple Quadrupole Mass Spectrometer(LC/QQQ). Two UV ink formulas were analyzed for residual PI content.  The ink formulas were optimized for cure, however this study only analyzed for PIs which were an SVHC or on the Nestlé list.  The inks were printed on glass plates, cured (2, 4, 6, 10, 12 passes at 64 mJ/m2/ pass), extracted and analyzed by LC/QQQ.  Residual content is reported as the percent of PI left after cure and as a function of cure passes.  For each PI, the residual content decreased from over 15% after 2 passes, to less than 7 percent after 14 passes.  Specifically, for 2-Benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone (PI 369; CAS119313-12-1; EC404-360-3), the residual content was less than what was deemed to be of “reasonable certainty to be no harm”.