Controlling Dye Migration

A good press operator is worth his/her weight in gold if they can keep churning out the shirts. If the press is not going around and the dryer belt is empty, no money is being made! Being able to set the job up correctly the first time and anticipate printing problems before they happen is a skill that is only learned over time. Controlling on press printing problems is no doubt the key to higher production output.

Dye migration is one of the problems that can be avoided by an experienced press operator. Plastisol inks can appear to give good opacity as the printed garment exits the dryer, but hours (or even days) later the dye from the garment can bleed through the cured ink film. Dye migration is a common problem when printing white ink on a red garment. Dyes in the garment will bleed through the ink for several reasons; excessive flash temperatures, excessive dryer temperature, and even garment storage. Garments kept in hot humid storage can also cause dye migration. Garment dyes heated up in the dryer will begin a "gassing" process that penetrates through the ink film tinting the ink to the color of the garment. One way to fight dye migration is to select an ink system that is opaque and has dye blockers added, also use 100% cotton Tee’s whenever you can. The absorbency level of natural fibers is much higher reducing garment dyes from bleeding through the plastisol print. Synthetic blends are much more prone to dye migration.

Avoid over-flashing. Over-flashing is a leading cause of dye migration. There are plastisols specially formulated to flash at lower temperatures. These fast flashing inks allow the ink to "gel" at a lower temperature for a shorter period of time. (3 to 6 seconds.) Leaving the flash over a print for an excessive amount of time (10 to 15 seconds) leads to major dye migration and bleeding problems. Ideal flash temperatures need to be in the 190°F to 230°F range. The solution is to speed up flash times: cover the shirtboards with a thin sheet of 70-durometer heat resistant neoprene. The neoprene cover insulates the shirt board directing the IR energy into the ink film instead of absorbing into the mass of the shirtboard. Covering your shirtboards with neoprene can cut flash times in half!