A Cooperative Project
between the
U.S. Environmental
Protection Agency
and the
Printing Trade
Associations
Nationwide
EPA742-F-95-011
FOR
THE
SCREEN PRINTING PROJECT BULLETIN 4
U.S.EPA
SCREEN PRINTING
"SS^fc. fc^^A^
SMARTER, SAFER SCREEN
RECLAMATION
Alternative System Chi
The chemicals used for screen reclama-
tion can be some of the most
hazardous products in a screen print-
ing facility. Typically, highly volatile solvents
are used. These cleaners may contain chemi-
cals that are harmful to the health of
employees if inhaled, ingested, or absorbed
through the skin. If they are not disposed of
properly, these products may also harm the
environment.
To reduce the hazards of screen recla-
mation to workers and to the environment,
screen printers using solvents for screen
reclamation should consider switching to one
of the safer substitute products currently on
the market. These substitutes often contain
less harmful chemicals and have a lower
volatile organic compound (VOC) content.
With a lower VOC content, the chemical is
less likely to be inhaled by employees or
released to the air
This bulletin highlights the characteris-
tics of one type of substitute product system
and compares it to a traditional (solvent-
based) screen reclamation system. Specifically,
this bulletin describes:
Performance of the alternative screen recla-
mation system as demonstrated in laboratory
tests and the two volunteer printing facilities;
The health and environmental risks of the
alternative system;
The cost of the alternative system.
Background
Initiated by industry, the DfE Screen
Printing Project was entirely voluntary and
involved almost all sectors of the screen
printing industry: manufacturers donated
their products for evaluation, staff from
Screenprinting and Graphic Imaging Associa-
tion International (SGIA) coordinated the
field demonstrations, the Screen Printing
Technical Foundation (SPTF) performed ini-
tial product testing, printers nationwide eval-
uated the products in their print shops, and
EPA staff conducted a risk assessment of the
products. One advantage of this coordinated
effort is that all product systems were evalu-
ated using the same methods. The consisten-
cy of the evaluations allows you to compare
the results to determine which of the alterna-
tives may be a viable substitute for your cur-
rent reclamation products.
-------
Promising
Performance
Performance was evaluated in two phas-
es: 1) performance demonstrations at SPTF's
laboratory under controlled conditions; and 2)
field demonstrations at volunteer printers'
facilities under the variable conditions of pro-
This bulletin highlights one alternative system referred
to as Alternative System "Chi." This system, as with all sys-
tems demonstrated in this project, is a real, commercially
available screen reclamation system; however, "Chi" is a
masked name. The actual trade name for this alternative sys-
tem (or for any of the alternative systems demonstrated) is
not used in this case study or in the final project report. Trade
names were masked for several reasons:
One of the goals of the DfE project is to illustrate the
process of searching for and evaluating cleaner alterna-
tives. DfE hopes to encourage you to incorporate envi-
ronmental concerns in your facility's decision-making
processes and into your discussions with suppliers. By
masking trade names, DfE encourages you to discuss the
characteristics of the products you use, or are considering
using, with your suppliers. This case study and the DfE
project help you to know what characteristics to look for
in the screen reclamation products you
purchase.
Since every screen printing shop is differ-
ent, manufacturers recognize that their
product's performance may vary greatly
depending on the operating conditions
and, moreover, printers' opinions of prod-
ucts will vary. In order to get their full
cooperation before the results were avail-
able, the Project complied with the
requests by some manufacturers that prod-
uct names be masked.
To compare the cost and risk of Alterna-
tive System Chi to a known system, a baseline
was established using a traditional solvent-
based screen reclamation system consisting of:
lacquer thinner as the ink remover, a sodium
periodate solution as the emulsion remover,
and a xylene/acetone/mineral spirits/cyclo-
hexanone blend as the haze remover. These
chemicals were selected because screen print-
ers indicated they were commonly used in
screen reclamation.
It should be noted the alternative recla-
mation systems were evaluated using a case
study approach; rigorous scientific testing was
not conducted. Instead, much of the informa-
tion presented here is based on printers' expe-
riences with these products as used at their
facilities.
duction. Since conditions vary greatly from one facility to the
next, printers felt it would be most valuable to evaluate per-
formance based on the experiences and opinions of the
experts: the printers who used the alternative products in
their print shops during the month-long demonstrations.
Each product system was demonstrated in two or three facili-
ties to get a more complete evaluation of performance under
a variety of operating conditions.
Laboratory Testing
During laboratory testing, three imaged screens were
reclaimed using Alternative System Chi: one where a solvent-
based ink was applied, the second with an ultraviolet-curable
(UV) ink, and the third with a water-based ink. In the lab,
two applications of the Chi ink remover were required to
remove the solvent-based ink. The UV-curable ink and water-
Ihemical Composit
Ink Remover
Alternative
System Chi
Diethylene glycol series ethers
Propylene glycol series ethers
N-methyl pyrrolidone
Ethoxylated nonylphenol
Lacquer thinner, consisting of:
30% Methyl ethyl ketone
20% Naphtha light aliphatic
20% Toluene
15% n-butyl acetate
10% Isobutyl isobutyrate
5% Methanol
Emulsion Remover
Sodium periodate
Water
1% Sodium periodate
99% Water
Haze Remover
Diethylene glycol series ethers
Propylene glycol series ethers
N-methyl pyrrolidone
Ethoxylated nonylphenol
10%Xylene
30% Acetone
30% Mineral spirits
30% Cyclohexanone
Clear concerns>Marginal concerns>Negligible concerns. Concerns were identified because
exact risks were not calculated. The information in this table is based on the September 1994
draft Cleaner Technologies Substitutes Assessment: Screen Printing Technical Report.
-------
U.S.EPA
based inks dissolved more easily, however an ink residue or
haze remained on all of the screens after applying the ink
remover. The emulsion remover easily dissolved the stencil
with only light scrubbing, leaving no emulsion residue
behind. When additional ink remover was applied (used
instead of a haze remover), it removed the ink residue and
lightened the stain on all three screens.
On-site Demonstrations
Two different facilities (referred to as Facility C and
Facility D) used System Chi for a month to evaluate how well
it performed in an actual production situation. The participat-
ing facilities recorded the amount of product used, the length
of time needed, and their opinion of how well the product
reclaimed the screen.
Health Risks1
Inhalation risks of the ink and haze removers are
negligible.
If you use the ink or haze remover on a daily basis
without wearing gloves, there is a clear concern for
harmful effects from diethylene glycol series ethers
absorbed through your skin. If gloves are worn, the
risk is negligible.
If your skin regularly contacts the ink or haze
removers, there is a concern for reproductive toxicity
risk from absorbing N-methyl pyrrolidone. If gloves
and safety goggles are worn, the risk is negligible.
There is a clear concern that regular, unprotected
contact with the emulsion remover will cause skin and
eye irritation and tissue damage. If gloves and safety
goggles are worn, the risk is negligible.
If you use the ink or haze remover on a regular
basis, there is a clear concern for harmful health
effects from inhaling the chemicals (specifically
toluene, methyl ethyl ketone, and acetone).
There is also a clear concern for adverse health
effects if your skin contacts the ink or haze remover
on a daily basis (from toluene, methyl ethyl ketone,
and acetone). The concern is marginal for contact with
cyclohexanone in the haze remover. If gloves and
safety goggles are worn, these risks are negligible.
There is a clear concern that regular, unprotected
contact with the emulsion remover will cause skin and
eye irritation and tissue damage. If gloves and safety
goggles are worn, the risk is negligible.
In on-site
demonstrations,
removed the ink well.
One of the facilities
found it worked very
well on metallic inks.
In lab testing,
dissolved UV-curable
and water-based ink
well. Two applications
were needed to
remove the solvent-
based ink.
Removed solvent
and UV inks with
moderate scrubbing
effort. A gray haze
remained on the
entire screen. With
water-based ink, the
ink solidified.
Quickly and
easily
removed the
stencil during
facility
demonstratio
ns and lab
tests.
Not
demonstrated2
At Facility C, the
haze remove
lightened
moderate stains,
but was not
effective on
heavy stains. At
Facility D, haze
remover was
not needed.In
lab testing, the
haze remover
lightened the
ink stain.
demonstrated'
2
The ink remover was demonstrated during laboratory tests as a component of a different reclamation
system.
Ink Remover Performance: At Facility C, the Chi ink
remover worked well, although in some cases, it acted more
slowly than their standard solvent blend. Facility D found the
ink remover worked well, especially on metallic inks.
Emulsion Remover Performance: The emulsion remover
worked very well at both facilities, dissolving the stencil
quickly and easily.
Haze Remover Performance: Alternative System Chi did
not include a separate haze remover; instead the manufactur-
er recommended applying the ink remover again to remove
any remaining haze. Facility D found their screens were com-
pletely clean after using just the ink and emulsion removers; a
haze remover was not needed. At Facility C, the haze
remover lightened the haze; however, when the haze was
heavy, a ghost image remained on the screen.
Overall Evaluation: At both facilities, the performance
of Alternative System Chi was as good as the performance
of the facilities' standard screen reclamation
products. The consistent performance of the
product at SPTF and in the two facilities
demonstrates that System Chi can work
under different operating conditions.
Reduced Risk
Occupational risks and environmental
releases associated with using Alternative
System Chi and the traditional system for
screen reclamation are summarized in the
table.
Whether using traditional screen recla-
mation techniques or an alternative system,
chemicals can get into your body either
through your skin when you contact the
product or through your lungs when you
inhale chemical vapors. Some chemicals have
a lower tendency to evaporate or to enter the
body through the skin; and different chemi-
cals have different effects, some more harmful
than others, once in your body. The risks
associated with inhalation of the chemicals in
Alternative System Chi were found to be neg-
ligible, while there is a clear concern for
chemical inhalation risk with the traditional
system. With the traditional system, daily
inhalation of toluene and methyl ethyl ketone
in the ink remover, and acetone in the haze
remover could lead to eye, nose, and throat
irritation, headaches, or fatigue. With Alterna-
tive System Chi, the adverse effects from
inhalation are negligible.
Applying either the Alternative System
Chi or the traditional system products regular-
ly without wearing gloves can be harmful to
your health. In the traditional system, these
effects are from the toluene and methyl ethyl
ketone in the ink remover, the sodium perio-
Facility C:
$3.89/screen
or
$5,829/year
Facility D:
$3.25/screen
or
$4,879/year
$6.27/screen
or
$9,399/year
-------
date in the emulsion remover, and the acetone in the haze
remover. In the alternative system, potential for these harmful
effects through skin contact are attributed to diethylene glycol
series ethers in the ink/haze remover, and sodium periodate
in the emulsion remover. If gloves and safety goggles are
worn regularly, however, the dermal risks from either system
are negligible.
Minimal Environmental Releases
Based on the EPA assessment, none of the chemicals in
either the traditional system or Alternative System Chi were
found to be hazardous to the environment in the quantities
used for screen reclamation. However, reducing the use of
the traditional chemicals could cut a facility's air releases.
Traditional screen-cleaning solvents often have a high volitile
organic compound (VOC) content, contain Hazardous Air
Pollutants regulated under the Clean Air Act, or contain a
RCRA listed or characteristic waste. Substituting an alternative
product for these screen reclamation chemicals could reduce
your facility's regulatory burden. Contact your state and local
regulatory authorities for information specific to your location.
Cost Savings
The performance demonstrations showed that both of
the participating facilities could reduce their costs for screen
reclamation by switching from the traditional system to Alter-
native System Chi. As with the risk comparisons, costs of
Alternative System Chi were compared to the costs of using
the traditional system. It was assumed 6 screens were
reclaimed daily and that all screens were 2,127 in2 (approxi-
mately 15 ft2) in size for both the traditional and the alterna-
tive systems. The cost estimate for each reclamation system
included labor time spent to reclaim the
screen, the cost of an average quantity of
reclamation products, and the cost of
hazardous waste disposal for RCRA-
listed waste or RCRA-characteristic
waste (ignitable based on flashpoint).
For the alternative system and the tra-
ditional system, RCRA issues apply only
to the traditional system ink remover.
For Facility C, their reclamation cost per screen would
drop by 38% from $6.27/screen to $3.89/screen for annual
savings of $3,560. At Facility D, the reclamation cost of
$6.27/screen using the traditional system would decrease 48%
to $3.25/screen at Facility D for the alternative system. Over a
year, the savings would amount to $4,520. The difference in
costs between the facilities is due to differences in the quanti-
ty of product used and the labor time required per screen as
recorded by each facility's employees.
For Mae Information...
Although the alternative system described in this case
study proved to be a viable alternative in the two printing
facilities where performance demonstrations were conducted,
it may not be the solution for all types of screen printing
operations. If you find that Alternative System Chi does not
seem like a feasible substitute for your facility, refer to the
summary booklet, Designing Solutions for Screen Printers: An
Evaluation of Screen Reclamation Systems, which includes
information on all the alternative product systems and alterna-
tive technologies evaluated. When you identify a product sys-
tem that seems like a potential substitute, contact your
supplier, identify the alternative system by its chemical com-
position, and discuss the characteristics of the products you
are looking for.
This bulletin is part of a series of bulletins and case
studies that provide screen printers with information on
products and techniques that can help them to prevent pol-
lution in their facilities. Information in these bulletins is
largely based on the work done by the Design for the
Environment Screen Printing Project. For copies of this bul-
letin, other DfE Screen Printing Project materials, or more
information about the project, contact :
Pollution Prevention Information Clearinghouse (PPIC)
U.S. Environmental Protection Agency
401 M Street, SW (7409)
Washington, DC 20460
Telephone: 202-260-1023
Fax: 202-260-4659
or
Screenprinting and Graphic Imaging Association Interna-
tional (SGIA)
10015 Main Street
Fairfax, VA 22031
Telephone: 703-385-1335
Fax: 703-273-2870
You may also contact the DfE Home Page at:
http://www.epa.gov/dfe or the SGIA
Home Page at http://www.sgia.org/
nTT) Recycled/Recyclable
Printed with Soy/Canola Ink on paper containing at
least 50% recycled fiber.
------- |