Coloration batch dyeing machines

Paper may be colored by dyeing the fibers in a water suspension by batch or continuous methods. The classic process is by batch dyeing in the beater, pulper, or stock chest. Continuous dyeing of the fibers in a water suspension is adaptive to modem paper machine processes with high production speeds in modem mills. Solutions of dyestuffs can be metered into the high density or low density pulp suspensions in continuous operation. 

Batch dyeing, on the other hand, processes fixed amounts of substrate in a machine, usually with a single treatment chamber. A batch (e.g., 100-1000 lb) of substrate is placed in the chamber and various solutions are imported for the different steps of the dyeing process. After each step, the processing solution is discarded. This method lends itself well to small amounts of substrate. However, batch dyeing is slower and produces more waste and batch-to-batch color variation, which is not generally seen in continuously dyed goods. 

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