Additive Cuts Ink Drying Time with No Mineral Oil Migration Problems

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Tightening regulations in North America, Europe, and elsewhere in the world during the past several years have spawned new barrier coating technologies that add significant costs to paperboards used for food packaging. Some of these coating also interfere with normal ink drying times, further raising costs and slowing print delivery schedules, as well as creating print quality problems. By accelerating cross linking reactions that normally occur in ink during drying, SpeedyDry dramatically steps up ink set time and thus reduces the opportunity for penetration of mineral oils through the board, possibly contaminating packaged foodstuffs.

SpeedyDry, which works well with almost all types of ink, attaches itself to the pigment and varnishes in the ink and then attaches to the substrate. Its properties create a chemical reaction that allows drying from top to bottom and side to side at the same time. It not only speeds drying times up to 75% in some applications, it also enhances ink gloss and increases adhesion of the ink on most hard to print substrates, including various plastics, while increasing rub resistance and eliminating chalking.

A series of migration tests conducted over the past several years show that results are acceptable with SpeedyDry at up to 20% of the ink mixture using various food packaging substrates including polyboard and recycled SBS (solid bleached sulfate) boards, as well as most recently (this past February) using Metsä Board's 240 gram Simcote coated folding boxboard.

The polyboard and SBS tests for fatty acid migration were conducted by ink supplier INX International at its R&D labs in Chicago. The inks were run under normal manufacturing conditions by a major packaging printer, and the migration testing used the approved fatty foods simulant of 95% ethanol in water at 40oC for 10 days. Gas chromatography testing with several meat and vegetable products then showed that both fatty acids and fatty acid esters remained well below the 6 ppm requirements of most national and international regulations.

The most recent testing by ISEGA in Germany (which also conducted earlier tests on the SpeedyDry product itself, showing it may be used safely as an ink dryer catalyst with food packaging) evaluated for hard water (cobalt and manganese) migration as well as mineral oil migration. ISEGA is one of only a few labs in the world that can do hard water (heavy metals) migration testing. The mineral oil testing included both the MOSH (paraffinic, naphthenic mineral oil hydrocarbons) and MOAH (aromatic mineral oil hydrocarbons) types.

In regard to cobalt, gas chromatography results showed that migration with all samples was lower than 0.05 mg/kg of foodstuff, and that the transfer onto dry foodstuffs would be significantly lower. Manganese in all samples ranged from 0.75 – 0.25 mg/kg (level of non-detectable) of foodstuff. The migration of mineral oils in all samples tested was well below the draft German regulation (No. 1935/2004, art. 3) of 0.6 mg/kg MOSH and 0.15 mg/kg MOAH.

The ISEGA tests show that the tested board grades printed using up to 20% SpeedyDry in the ink are well within current German regulations (which meet or are more stringent than most other country regulations for mineral oil migration) and may be used for food packaging. Further, ISEGA notes that food packaging materials printed with SpeedyDry may come into direct contact with dry, non-fatty foodstuffs on their non-printed sides. Contact with the non-lacquered side with fatty foodstuffs is also allowed.

More information about Speedy Dry is available online or by calling 1-336-261-0170.