New JMC's Process: Higher Stickies Removal and Better Decontamination Together with Optimized Bleaching, 1993 Papermakers Conference Proceedings

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The conventional recycling processes have shown their limits for the treatment of highly contaminated and hard-to-deink waste paper, such as xerographic or laser printed paper, old offset glued-back telephone directories. Having to re-use such grades for the production of graphic papers, it was decided to search for new techniques adopting a “process-orientated” approach instead of the most usual “machinery-orientated” one.

The optimum operating parameters of the specific elementary processes which compose any general recycling process have been identified. These elementary processes required opposite optimum values of the same parameters.

Temperature and energy are harmful on thermo-sensitive contaminants but necessary for ink particles detachment.

Alkalinity helps the removal and the dispersion of the oil or resin based ink particles but increases the solubility of stickies and water based flexographic ink.

Hydrogen peroxide is used at operating parameters which are very far from those for which this process has been designed.

These elementary processes have been rearranged into an industrial process in which the two steps of decontamination and final deinking have been separated, in order to optimize the specific parameters for each operation without secondary negative effect on the other one.

Comparative results are shown and confirm the main advantages of this process:

- Highest possible removal of the stickies and the hot melts;

- Complete detachment of the ink particles from the surface of the fibers;

- Optimized bleaching during the recycling process.