Materials designed for high elongation can pull you in the wrong direction if you don
By Rick Davis
Flashing is only required when you print an underbase onto a dark fabric to increase the vibrancy of an overprinted color. A high-elongation-plastisol ink film requires additional time between flashing and printing to allow the after-flash tack to disperse from the ink film’s surface.
When printing on an automatic, you will need at least one cooling station on the press to allow the ink film sufficient time to cure prior to overprinting. Otherwise, the result could be disastrous: The screen following the flashed underbase would adhere to the hot, flashed ink film and pull the ink and fabric from the platen surface. The obvious result would be a complete loss of registration and thus the scraping of the garment. Keep in mind that as low-temperature inks cure at a lower temperature, they also flash at a lower temperature.
Even though high-elongation plastisols cure at lower temperatures than conventional formulations, you’ll still need to ensure proper cure throughout the ink film. Should the entire ink film not reach its required temperature, the results will be poor elongation and cracking due to insufficient heat, poor abrasion resistance, poor washability, and possible flaking of the ink film due to poor adhesion.
You have a number of different methods for determining the temperature the ink film reaches, but the best test to determine state of cure is to wash the garment and stretch it once it’s dried. The ink film should support at least a 300% elongation from its static state. Should the ink not stretch, or if it shows any of the previously mentioned characteristics associated with poor performance, you will know that the ink did not receive sufficient heat. The same holds true should the ink film receive excessive heat.
Stretch your printing expertise
The printing of specialty high-elongation fabrics can be productive and profitable once you identify the correct printing parameters to match the fabric characteristics. Putting the proper procedures and controls in place, as well as understanding the fundamentals associated with the material, will allow for maximum flexibility on fabrics of this type.
QUICK FACTS ABOUT SPANDEX
Spandex was first commercially produced in the US in 1959 by DuPont. The synthetic fiber is stronger than rubber and is designed to recover to almost precisely its original shape and length after repeated stretching—and it can do so to more than 500% without breaking. Spandex is a lightweight material that is heat-settable, dye-receptive, and resistant to damage from abrasion and deterioration from exposure to detergents, lotions, body oils, and more. Fibers are available in 10-2500 denier.
Rick Davis is the president of Synergy Screen Printing in Orlando, FL. A 27-year veteran of the textile-printing industry, Davis is a member of the Academy of Screen Printing Technology and has a background that spans production management, artwork engineering, application testing, and industry consulting. He is a frequent contributor to trade publications and a speaker at industry trade events.
Did you enjoy this article? Click here to subscribe to the magazine.