United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-95/023 August 1995
ENVIRONMENTAL
RESEARCH BRIEF
Pollution Prevention Assessment for a Manufacturer of
Pressure-Sensitive Adhesive Tape
Harry W. Edwards*, Michael F. Kostrzewa*, and
Gwen P. Looby**
Abstract
The U.S. Environmental Protection Agency (EPA) has funded
a pilot project to assist small and medium-size manufacturers
who want to minimize their generation of waste but who lack
the expertise to do so. In an effort to assist these manufactur-
ers Waste Minimization Assessment Centers (WMACs) were
established at selected universities and procedures were
adapted from the EPA Waste Minimization Opportunity As-
sessment Manual (EPA/625/7-88/003, July 1988). That docu-
ment has been superseded by the Facility Pollution Prevention
Guide (EPA/600/R-92/088, May 1992). The WMAC team at
Colorado State University performed an assessment at a plant
that manufactures three varieties of pressure-sensitive tape.
Tape production involves the three basic operations of backing
fabrication, coating, and slitting. Three separate coating opera-
tions are used, as determined by the type of tape being
manufactured (natural rubber, acrylic, or hot-melt). The team's
report, detailing findings and recommendations, indicated that
waste natural rubber adhesive is shipped offsite for disposal in
large quantities, and that significant cost savings could be
achieved by redesigning the adhesive applicator on the coater
for natural rubber adhesive.
This Research Brief was developed by the principal investiga-
tors and EPA's National Risk Management Research Labora-
tory, Cincinnati, OH, to announce key findings of an ongoing
research project that is fully documented in a separate report
of the same title available from University City Science Center.
* Colorado State University, Department of Mechanical Engineering
" University City Science Center, Philadelphia, PA
Introduction
The amount of waste generated by industrial plants has be-
come an increasingly costly problem for manufacturers and an
additional stress on the environment. One solution to the
problem of waste generation is to reduce or eliminate the
waste at its source.
University City Science Center (Philadelphia, PA) has begun a
pilot project to assist small and medium-size manufacturers
who want to minimize their generation of waste but who lack
the in-house expertise to do so. Under agreement with EPA's
National Risk Management Research Laboratory, the Science
Center has established three WMACs. This assessment was
done by engineering faculty and students at Colorado State
University's (Fort Collins) WMAC. The assessment teams have
considerable direct experience with process operations in manu-
facturing plants and also have the knowledge and skills needed
to minimize waste generation.
The pollution prevention opportunity assessments are done for
small and medium-size manufacturers at no out-of-pocket cost
to the client. To qualify for the assessment, each client must
fall within Standard Industrial Classification Code 20-39, have
gross annual sales not exceeding $75 million, employ no more
than 500 persons, and lack in-house expertise in pollution
prevention.
The potential benefits of the pilot project include minimization
of the amount of waste generated by manufacturers, and
reduction of waste treatment and disposal costs for participat-
ing plants. In addition, the project provides valuable experi-
ence for graduate and undergraduate students who participate
in the program, and a cleaner environment without more regu-
lations and higher costs for manufacturers.
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Methodology of Assessments
The pollution prevention opportunity assessments require sev-
eral site visits to each client served. In general, the WMACs
follow the procedures outlined in the EPA Waste Minimization
Opportunity Assessment Manual (EPA/625/7-88/003, July 1988).
The WMAC staff locate the sources of waste in the plant and
identify the current disposal or treatment methods and their
associated costs. They then identify and analyze a variety of
ways to reduce or eliminate the waste. Specific measures to
achieve that goal are recommended and the essential support-
ing technological and economic information is developed. Fi-
nally, a confidential report that details the WMAC's findings
and recommendations (including cost savings, implementation
costs, and payback times) is prepared for each client.
Plant Background
This plant manufactures adhesive tape that is distributed na-
tionally and internationally. Over 100 million m2 of tape are
produced each year during 24 hr/day production.
Manufacturing Process
Three varieties of pressure-sensitive adhesive tape—natural
rubber, acrylic, and hot-melt—are produced by the plant. Sev-
eral colors of tape, sold in rolls of 1-1/2 to 6 inches in width, are
manufactured.
Tape production involves the three basic operations of backing
fabrication, coating, and slitting. The backing, or non-stick sur-
face of the tape that gives it strength, is made from polypropy-
lene film in a cast-film process. Polypropylene pellets are
melted in electricallyheated extruders, and the resulting molten
plastic is applied to the top of a rotating cylinder and cooled
into a sheet in a water bath at the bottom of the cylinder.
The material is pulled from the die with a width of about one
meter and a thickness of 1.5 to 2 mm. Then the film is
stretched by rollers to over five times its original length and by
mechanical "fingers" to about seven times its original width as
it is heated in an oven. After stretching, the backing is cooled
over water-cooled rollers. Next, the edges of the backing are
trimmed; these trimmings as well as other backing waste, are
shredded, melted, pelletized, and reused.
The final stage in the backing process involves the use of a
pull-rod stand, where 12,000 m of backing material with a width
of 6 m are rolled onto a balanced steel roller. A bridge crane
transports the rolls to a slitting machine, where the rolls are
unrolled, cut to smaller widths, and re-rolled into shorter lengths.
A small percentage of the resulting rolls is sold as a finished
product. The remaining rolls are transported to the coating
areas.
Three separate coating operations are used to make the three
varieties of tape produced. Production of acrylic tape begins by
unwinding the film and feeding it into the coating machine.
Acrylic adhesive is applied to one side of the film and the tape
is then passed through a steam heater to dry the adhesive
while maintaining proper moisture levels. Finished tape is then
wound onto temporary rollers.
Fabrication of natural rubber tape follows a similar process.
Film is unwound and fed into a coater. A release coat, which
prevents the tape from adhering to itself on the roll, is applied
to one side of the film. A primer coat, which prepares the
surface of the film for the adhesive, is applied to the other side.
Then the tape passes by a reservoir where the natural rubber
adhesive flows onto the film in a thin coat. The film passes
through a chamber where the solvent carriers evaporate. The
vapors are collected using a recovery system and reused.
Finally, the finished tape is wound onto temporary rollers.
Hot-melt tape fabrication begins by unwinding the film and
feeding it into a coater. A release coat is applied to one side of
the film and the hot-melt adhesive, which has been melted with
electric heaters, is applied to the other side. Evaporated sol-
vent carrier is recovered and reused as in the natural rubber
tape production process. The finished tape is then wound onto
temporary rollers.
The temporary rollers from the three coating operations are
taken to the slitting area, where the tape is unrolled, slit, and
rewound onto paper cores of various widths. The finished tape
rolls travel down a conveyor to a boxing station. After inspec-
tion, the boxes are sealed, sorted, loaded, and stored or
shipped to customers.
An abbreviated process flow diagram for the production of
pressure-sensitive adhesive tape is shown in Figure 1.
Existing Waste Management Practices
This plant already has implemented the following techniques to
manage and minimize its wastes.
• Water usage for clean-up of the acrylic tape coater is limited
to a specific quantity per shift.
• A portion of the waste natural rubber adhesive from the
coater is reused in subsequent product formulations.
• Evaporated carrier solvents are recovered and reused. The
vapor recovery system is being redesigned to improve its
efficiency.
• Waste film trimmings are pelletized and reused.
• Waste hot melt adhesive purged from equipment lines is sold
when possible.
• Waste release that becomes too thick for use is diluted and
reused.
Pollution Prevention Opportunities
The type of waste currently generated by the plant, the source
of the waste, the waste management method, the quantity of
the waste, and the waste management cost for each waste
stream identified are given in Table 1.
Table 2 shows the opportunity for pollution prevention that the
WMAC team recommended for the plant. The opportunity, the
type of waste, the possible waste reduction and associated
savings, and the implementation cost along with the simple
payback time are given in the table. The quantities of waste
currently generated by the plant and possible waste reduction
depend on the production level of the plant. All values should
be considered in that context.
It should be noted that the economic savings of the opportunity
results from reduction in raw material and costs associated
with waste treatment and disposal. Other savings not quantifi-
able by this study include a wide variety of possible future
costs related to changing emissions standards, liability, and
employee health.
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Additional Recommendations
In addition to the opportunity recommended and analyzed by
the WMAC team, several other measures were considered.
These measures were not analyzed completely because of
insufficient data, implementation difficulty, or a projected lengthy
payback. Since these approaches to pollution prevention may,
however, increase in attractiveness with changing conditions in
the plant, they were brought to the plant's attention for future
consideration.
• Reformulate the natural adhesive, primer, and release coat
using a single solvent as the carrier for each.
• Develop a program to test the release periodically for param-
eters that can determine its effective life. Discontinue the
practice of arbitrarily replacing the release.
• Install a solvent recovery unit for processing waste toluene
onsite.
• Monitor the development and application of the Brayton-
cycle heat pump for use in recovering solvent vapors.
This research brief summarizes a part of the work done under
Cooperative Agreement No. CR-819557 by the University City
Science Center under the sponsorship of the U. S. Environ-
mental Protection Agency. The EPA Project Officer was Emma
Lou George.
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Polypropylene
Pellets
Extrusion
Trimming
Stretching
Slitting
Large Film
Rolls
Acrylic
Adhesive
Application
Release Application
Primer Applica tion
Natural Rubber
Adhesive Application
Smaller Rolls
to Slitters
Release
Application
Hot-Melt
Adhesive
Application
Slitting
Inspection
Packaging
Finished Tape Rolls
to Customers
Figure 1. Abbreviated process flow diagram for pressure-sensitive adhesive tape production.
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United States
Environmental Protection Agency
National Risk Management Research Laboratory (G-72)
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/S-95/023
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