Davis explains why determining how a high-performance polyester garment will behave on press and in the dryer is a critical part of a successful print run.
By Rick Davis
While you’re at it, take a moment to call the garment manufacturer directly and ask what printing parameters and products they suggest to properly decorate and finish the fabric. The response you get may range from detailed instructions on each step of production and suggested applications to the far extreme of, “The fabric was not intended to be imprinted.”
Heat sensitivity is a huge consideration when screen printing fabrics. Typically, 100%-polyester fabrics are heat set to 360°F to ensure that the fabric will be fade resistant during washing. This may not always be the case, depending on the fabric manufacturer’s dyeing and heat-setting applications.
One case I experienced just this year was excessive shrinkage of the garment during the curing process. In most cases you can lose a half of an inch in length or width when the garments pass through the dryer. But in this particular situation, I had a garment style that lost six inches in length and an inch in width when the printed apparel passed through the dryer. I was lucky in this case, because the manufacture was aware of the issue and accepted a return of the garments. Here again, it is a good idea to inquire as to a fabric’s sensitivity to heat to avoid such disasters. Obviously, issues with dye migration only apply to dark to medium fab-ric colors, whereas the shrinkage issue can apply to any color of performance fabric.
Minimize the ink film
From an application standpoint, always remember that more is not necessarily better. Do not go into your performance testing with the assumption that laying more ink down can solve your potential bleeding issues. Thicker ink films require a greater dwell time in the dryer chamber, thus exposing the fabric to high temperatures for a greater period of time than necessary. Doing so can, in this case, create more problems than it may solve.
You’re better off printing such fabrics with screens tensioned as high as you can support and by depositing as little ink onto the fabric as possible in order to minimize the amount of time needed to properly cure the ink film. Another option worth consideration is working with low-temp/fast-fusion inks—high-opacity inks that allow you to cure at lower temperatures and decrease the potential issues that the higher temperatures may cause.
Why you must test
None of the suggestions I’ve described is an absolute. The situation changes with each 100%-polyester fabric and with each man ufacturer. Also keep in mind that a majority of these fabrics are most likely produced in Asia, under questionable quality-control standards. That, perhaps, is among the biggest reasons why you must always test the fabrics you print.
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.