Impressions - February 2015 - 56

Screen Printing Production

Figure 4. Here, you can see the documented temperatures of a dryer
with a 60-second retention time.

is when a print is exposed to excessive
heat. This typically occurs when the ink
ﬁlm receives too much heat during the
ﬂashing process and then reaches the remelting point in the dryer. Remember,
standard plastisols cure at 320˚F. Should
an ink ﬁlm reach above that temperature
(typically 360˚F), the dried ink ﬁlm will
re-melt, resulting in the destruction of
its durability.
The most common sign that an ink
ﬁlm is overcured or re-melted is blistering.
This will happen with bleed-resistant inks
where the bleed-resistant agents start to
boil. The result is a cratering effect, where
the ink ﬁlm will look like the Moon's surface under a magniﬁer. This is an example
of the caution you must use when trying
to reach the proper curing temperature,
while also avoiding the re-melting point.

TEST METHODS
As our industry has never had an actual
"how-to" reference on its respective processes, the method for determining proper
cure tends to vary from among facilities.
One of the greatest missteps I've seen involves determining the degree of cure by
stretching the dried (and hopefully cured)
ink ﬁlm. Stretching an ink ﬁlm simply reveals the elongation characteristics of that
particular ink. You may have an ink with
56

Impressions | February 2015

excellent elongation characteristics, but it
still could be undercured.
This leaves one tried-and-true test
method - the wash test - which will be
repeatedly performed by the customer. This
should be regularly conducted by screen
printers to ensure the print is properly
cured. When possible, printed garments
should undergo as many as ﬁve wash tests.

As our industry has
never had an actual
"how-to" reference
of its respective
processes, the method
for determining proper
cures tends to vary
from among facilities.
When you have successfully washtested a garment, and know the dryer
and ﬂashing procedures are set, you can
standardize those settings and use any of
the aforementioned heat-measurement
tools to ensure the process remains
consistent. Conducting a proper wash
test is insurance that the customer will

not have issues once orders have left
your facility.
Rick Davis is the southeastern regional
sales manager for Triangle Ink Co. He is a 35year veteran of the textile screen-printing and
apparel manufacturing industries. His background includes plant design, management
and troubleshooting, and he also is a member
of the Academy of Screen Printing Technology.
For more information or to comment on this
article, email Rick at rickd5050@yahoo.com.
Hear Rick speak on screen-printing
topics at the 2015 Imprinted Sportswear
Shows (ISS). Individual seminars are just
$25 if you pre-register: issshows.com.

Suggested

Reading

Like this article? Read these and
other screen-printing articles at
impressionsmag.com:
* "Screen Printing Tip of the Week:
Curing Ink with a Heat Gun"
* "Screen Printing Tip of the
Week: Low-Cure Additive"
* "How to Ensure a Print is
Correctly Cured"
impressionsmag.com

http://www.issshows.com http://www.impressionsmag.com http://www.impressionsmag.com

Impressions - February 2015

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