The cause of this problem is most likely due to the fact that the ink is not cured properly. Plastisol ink needs to cure at a minimum temperature of 320º F for at least one minute. This allows the molecules to properly fuse to each other as well as to the fabric.

There are many variables that can affect ink curing, such as humidity and colder air temperatures. Therefore, it’s important that the ink itself—and not the garment or just the dryer temperature—reaches 320º F. In colder weather, this may mean increasing the dryer temperature or allowing the ink to pass through a bit longer than one minute.

—Ed Branigan, International Coatings