Impressions - March 2019 - 40

More About Printing on Poly
Depending on the garment brand being used, one approach to printing low-cure plastisol inks
on polyester is to use a 156 mesh (or higher), flash and then print a second ink layer to achieve
good results.
Many of today's polyester garments are treated with a process that makes the garment more
colorfast and less prone to bleed. When printing such polyester garments, a low-cure plastisol
can be printed through a 305 mesh with a print, flash, print sequence to achieve an opaque,
smooth print.
However, treated red polyester fabrics still can bleed unless a gray or black underbase is
printed first and flashed, with the subsequent colors being printed on top. This gray underbase
technique has become mainstream during the past five years and some formulations contain
a high percentage of carbon that traps the garment dye, allowing the colors printed on top to
stay bright and opaque.

Low-cure plastisols are ideal for printing
on polyester athletic jerseys.The lower cure
temperature allows printed colors to stay
bright on a variety of background colors.
Photo courtesy of Wilflex.
P.40

i m p r e s s i o n s m a g . c o m MARCH 2019

Since cotton is absorbent, the dyes used
to color the fabric are more stable and less
prone to bleed through the ink printed on
the surface. However, within the cotton
category are the popular garment-dyed
T-shirts that have been vat dyed after the
T-shirt was sewn.
Printing Tips: Cotton can be printed
with standard plastisol, water-based and
other non-PVC textile inks with very
few printing issues. However, printing on
garment-dyed goods, like those from Comfort Colors, requires more attention to
detail and a gray underbase to be printed
first, then flashed, with the subsequent colors printed on top to keep the dye from
penetrating the ink film.
2. Polyester: When polyester garments
first were introduced to the market, screen
printers used standard plastisol inks - cured
at 320˚F - to print on these fabrics with
some success. However, printing with these
higher-cure-temperature inks caused a
problem with dye migration due to dryer
temperature settings in the 320˚F-350˚F
range.
In addition, standard plastisol inks don't
have the stretch properties that the new
performance plastisols offer. But the good
news is there now are low-cure, highelongation plastisols available for printing
on 100% polyester fabrics. They cure in
the 275˚F-290˚F range, just below the
temperature that causes polyester fabrics
to sublimate and release the garment color
through the ink film.
"Traditionally, water-based inks have
always had great success when printed
on cotton fabrics, whether it be soft
base on light garments, or creating a
very soft feel by printing with a discharge base, which provides a solution
for printing on specific dark cotton
garments," says Ray Smith, an application specialist at Wilflex. "To meet the
challenges of printing on dark garments
that don't discharge well, high-solids,
water-based products have flourished.
For printing on polyester and polyester
blends, the same high-solids, water-based
inks can be used when printed over a
bleed-blocking layer - usually a black -
that stops the fabric dye from migrating
into the ink film."
Printing Tips: A common technique
for printing a white image on polyester
is to print a low-cure white through a
156 mesh, then flash and print a second
white on top with a 230 or 305 mesh
to achieve a smooth, opaque print. Some
polyester fabrics are brushed during the

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Impressions - March 2019

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