Printing newspaper free of mineral oil: report on a test run

The Swiss retailer Coop printed part of his weekly newspaper with inks formulated without mineral oil. The experiment explored this approach to reduce the migration of mineral oil into food when newspaper is recycled to paperboard for food packaging. The mineral oil was replaced by plant oils as well as poly alpha olefins (PAO) with the lowest mass above the n-alkane C₂₄, i.e. of a volatility low enough to prevent transfer through the gas phase into food. With this composition, no major adjustments of the printing machine were necessary. The printing quality was judged excellent by the International Newspaper Color Quality Club (INCQC). As the carryover in the installations was known to be a serious problem, 30 t of inks were used, initially printing daily newspapers and other printed material. Measurement of the residual mineral oil in the inks as delivered to the printing plant and monitored at the top of a printing tower confirmed that no rapid exchange of inks is possible.