A Cooperative Project
between the
U.S. Environmental
Protection Agency
and the
Printing Trade
Associations
Nationwide
FOR
THE
ONMENT
SCREEN PRINTING PROJECT CASE STUDY 3
U.S.EPA
SCREEN PRINTING
Innovations in Adhesives, Screen
Cleaning, and Screen Reclamation
This case study describes how T.S.
Designs, a textile screen printer in
Burlington, North Carolina, used ini-
tiative and creativity to prevent pollution at
its facility. In doing so, the company mini-
mized risk to workers and the environment,
greatly reduced its solvent use, and
increased its cost efficiency.
Background
T.S. Designs began textile screen print-
ing in 1977 and today processes 4.5 million
articles of clothing per year. The company
employs 55 people, about a third of whom
are directly involved in production. T.S.
Designs mainly uses plastisol inks, which
are polyvinyl chloride-based, although it
does occasionally use water-based inks when
requested by customers. Currently, T.S.
Designs produces mostly T-shirts, but also
prints sweatshirts, piece goods, and hosiery
products. The materials include both syn-
thetic and natural fibers. The firm's primary
market is contract screen printing for large
sportswear companies. The company also
prints for local schools, restaurants, clubs,
and other organizations.
Automated Adhesive
Application Process
T.S. Designs began reducing its sol-
vent use in 1991 as a quality control issue,
not for environmental reasons. At that time,
This case study shows how:
• Water-based adhesives can
effectively replace solvent-based
adhesives in the textile printing
process.
• Solvent use can be drastically
reduced by reusing chemicals in
enclosed screen cleaning and
reclamation tanks.
the company used a solvent-based spray
adhesive to hold T-shirts in place on a platen
while the image was applied. The adhesive
came in 12- and 16-ounce aerosol cans, and
workers manually sprayed it onto the platen.
The process was imprecise, and if a worker
sprayed too much or too little adhesive, the
printed image would often be defective.
The company wanted to lower the
number of products rejected due to incorrect
adhesive application. It contacted several
chemical companies to discuss automating
the adhesive application process. Several
partially automated systems did exist, but
given the large quantity of textiles the com-
pany prints and its quality control require-
ments, the firm decided to design and build a
totally new, fully automated system. The
new system would be tied electronically to
the printing machine, and could precisely
control when and how much adhesive is
applied.
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FOR
THE
WNL
Water-Based Adhesives
As T.S. Designs began researching
the application options, the company
also considered the cost, waste, health,
and safety issues related to the adhesive
itself. It found many disadvantages to
continuing to use the solvent-based
adhesive. Because it was flammable, and
countless adhesive-filled aerosol cans
were used throughout the plant, the
company faced the risk of a can acciden-
tally being dropped onto a conveyor belt
and being carried into a dryer, causing a
small explosion or fire. The company
also determined that if it switched to an
automated system that used air pressure
to apply the solvent-based adhesive,
there could be performance problems.
Moreover, the solvent-based adhesive
had possible adverse health effects—it
contained 1,1,1-trichloroethane, which
can cause dizziness or light-headedness
or more serious effects from longer
exposures.
Replacing the solvent-based adhe-
sive with a water-based adhesive—a type
commonly used before the invention of
solvent-based adhesives—was consid-
ered. The company realized, however,
that by today's standards, the thicker
water-based adhesive would take too
long to dry and would clog the spray
nozzles of an automated system. Thus,
the company began looking for a thinner
water-based adhesive that would be more
compatible with modern automation.
T.S Designs used all the resources
available to determine the right combi-
nation of adhesive and automation for
its application process. It brought
together teams of employees and also
spoke to representatives from other
industries, such as the automobile indus-
try, who had experience with similar
spray systems. In addition, the company
worked with the Screenprinting and
Graphic Imaging Association
International (SGIA) and participated in
an EPA study that tested several water-
based adhesives.
The New Adhesive
Application Process
Ultimately, through testing, T.S.
Designs found that a very fine spray of a
water-based adhesive would dry quickly
and not clog its system of nozzles.
Automated systems using this adhesive
were then installed on six of the compa-
ny's seven presses. The adhesive is
stored in one place in 5 5-gallon drums
and pumped to the presses where the
amount of adhesive applied to the T-
shirts is controlled by computer. The
system has reduced T.S. Designs' use of
solvent-based adhesive by 91 percent,
from 4,800 to 430 aerosol cans a year.
This, in turn, has greatly decreased the
release of potentially health-threatening
chemicals into the environment.
Not long after implementing this
change, T.S. Designs encountered an
obstacle. Over time, the thinner adhesive
coated and eventually clogged the noz-
zles. A contact in the automobile indus-
T.S. Designs' automatic glue sprayer effectively reduces costs.
try recommended more advanced noz-
zles. Though they were more expensive,
the cost was offset by better perfor-
mance. The more advanced nozzles
allowed the machines to operate longer
and more smoothly.
The new automated adhesive
process required total equipment pur-
chases of about $12,000 ($2,000 per
press), but the water-based adhesive is
considerably less expensive than the sol-
vent-based one. The
new system paid
for itself through
I reduced adhe-
sive costs in
about 2 years,
and now saves
T.S. Designs
roughly $6,000 a
year. Quality also has been greatly
improved by the much higher level of
control afforded by the automated
process.
Automated Ink Removal
and Enclosed Emulsion
Removal Systems
T.S. Designs also found that its ink
removal and emulsion removal process-
es had room for improvement in effi-
ciency, health, and environmental
considerations.
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U.S. EPA
In 1992, the company used tradi-
tional ink removal and emulsion removal
processes that required the use of several
hazardous chemicals. The first part of the
ink removal process, carding out the
screens, required workers to remove
excess ink with cardboard cards. Next,
workers applied a diluted ink remover
detergent to the screens. The detergent
contained glycol ethers (less than 30 per-
cent), petroleum distillate (less than 5
percent), and d-limonene (less than 20
percent). For the emulsion removal
problems if regulations became more
stringent. In addition, the old system used
large amounts of water and was very
labor intensive.
Automated Ink Removal
System
The firm sought out ways to
improve its ink removal and emulsion
removal processes at every level.
Beginning with the carding out phase, it
T.S. Designs' enclosed reclaim tank has cut the company's use of water in half.
process, workers applied an emulsion
remover consisting partially of peracetic
acid (25 to 30 percent). Occasionally, if a
stain still remained on the screens, work-
ers used a haze remover containing
alkylphenoxypolyethoxyethanol (less
than 18 percent). To complete the
process, they used a degreaser with a
small amount of propylene glycol ether
(3 percent). After each step in the ink
removal and emulsion removal processes,
the chemicals were washed through the
screens with a very low-pressure water
stream. The resulting mixture was then
washed down the drain in compliance
with local, state, and federal regulations.
Even though the old system was in
compliance, T.S. Designs knew that the
fewer chemicals it sent down the drain,
the lower their impact on the environ-
ment. The company also stood less
chance of avoiding future compliance
eliminated the thousands of cardboard
cards and replaced them with reusable
cards made from scrap Formica. Next,
the company improved the application of
its ink removal chemical. It identified and
installed an automated closed loop sys-
tem that did not need water and did not
send ink down the drain. This system
simply requires workers to put the screen
inside an enclosed tank, and the equip-
ment does the rest, much like an industri-
al dishwasher.
This new enclosed system allows
chemicals to be applied in a much more
controlled environ-
ment. They can be
recycled many
times and waste
is greatly
reduced.
This reuse
process keeps
approximately 1,000 gallons of solvent a
year out of the wastewater system. The
new system cost nearly $13,000 to install,
but saves T.S. Designs over $20,000 in
reduced labor and purchasing costs annu-
ally.
Enclosed Emulsion
Removal System
The emulsion removal process pre-
sented many of the same concerns as the
ink removal process. Too many haz-
ardous chemicals were being washed
down the drain, and workers were spend-
ing too much time applying the chemi-
cals, waiting for them to loosen the
emulsion, and washing off the screens.
T.S. Designs started experimenting with
its emulsion remover chemical. It found
that much smaller amounts of the chemi-
cal, if left on the screen longer, were just
as effective as the amount the company
had been using. Although the chemical
looked dirty after use, it could be reused
many times and still successfully reclaim
the screens.
T.S. Designs used this new informa-
tion to design and build its own enclosed
system. Similar to the ink removal sys-
tem, workers place the screen in a tank
where it is soaked in emulsion remover.
This chemical softens the emulsion.
Workers then remove the screen from the
tank and wash out any remaining emul-
sion with gray water recycled from the
degreasing process (described below) at a
pressure of 200 pounds per square inch.
Previously, T.S. Designs used roughly 90
gallons of emulsion remover a month, but
now about 25 gallons are recirculated
through the system each month. This
recirculation reduces the amount of emul-
sion remover purchased and disposed of
by about 780 gallons a year, saving over
$900 in purchasing costs annually. These
purchasing savings allowed the firm to
recoup its labor and equipment costs for
designing and implementing the new
emulsion removal system in just over a
year. In addition, the effectiveness of the
ink removal and emulsion removal sys-
tems has allowed the firm to virtually
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desma
ENVffiONMENT
eliminate the haze remover step.
The final step in reclaiming a screen
is the degreasing process, in which the
screen is given a final rinse with fresh
water. This process also takes place in
an enclosed tank. The used water is
stored and then pumped back to be used
in the emulsion removal tank. This recy-
cling step has cut the company's use of
water in half, saving 630 gallons a week.
Taken together, new systems have
substantially reduced the company's
impact on the environment, decreasing
the company's chemical use by 86 per-
cent, and cutting water and energy con-
sumption as well. By making the effort,
the company discovered alternatives that
are not only cost-effective, but that also
reduce risks to workers and the environ-
ment.
For More Information
For more information on the tech-
nologies discussed in this case study,
contact your equipment suppliers. For
more detailed information on other tech-
nological and chemical alternatives,
refer to the summary booklet Designing
Solutions for Screen Printers: An
Evaluation of Screen Reclamation
Systems. Additional case studies and
bulletins are also available. For more
information on EPA's Design for the
Environment Program or to obtain the
case studies, bulletins, and other related
materials, contact:
Pollution Prevention Information
Clearinghouse (PPIC)
U.S. EPA
401 M Street, SW. (7409)
Washington, DC 20460
Phone: 202-260-1023
Fax: 202-260-4659
World Wide Web:
http://www.epa.gov/opptintr/
p2home/ppicdist. htm
For more information on this case
study, contact:
Eric Henry
President
T.S. Designs, Inc.
2035 Willow Springs Lane
Burlington, NC 27215-8854
Phone: 910-229-6426
Fax: 910-226-4418
E-mail: eric@netpath.net
World Wide Web:
http://www.tsdesigns.com
For trade association information,
contact:
Screenprinting and Graphic
Imaging Association
International (SGIA)
10015 Main Street
Fairfax, VA 22031
Phone: 703-385-1335
World Wide Web:
http ://www. sgia. org
Also be sure to investigate your
local health and environmental regula-
tions. Local agencies are familiar with
priority issues in your area and can help
you find the best ways to prevent pollu-
tion in your community.
Mention of trade names, companies, or
commercial products does not constitute
endorsement or recommendation for use
by either the U.S. Environmental
Protection Agency or other firms, orga-
nizations, or individuals who have par-
ticipated in the preparation of this
publication.
What Is the Design for the Environment
Screen Printing Project?
The U.S. Environmental Protection Agency's (EPA's) Design for
the Environment (DfE) Screen Printing Project is a voluntary project that
encourages printers to consider environmental concerns along with cost
and performance when purchasing products to use in their facilities.
Replacing hazardous chemicals with environmentally safer substitutes is
one way to reduce the impact of printing on the environment while maintaining product
quality. Many printers, however, have limited time and resources and therefore need help
identifying and testing environmentally safer substitutes.
DfE fills this information gap. EPA has teamed up with screen printing industry rep-
resentatives (including trade associations, printers, and suppliers) in the DfE Screen Printing
Project. The project's goal is to evaluate and publicize pollution prevention opportunities in
screen printing, particularly in the screen reclamation process.
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