Packaging Tapes: To Recycle Or Not, And If So, How?
Timothy B. Jensen, Ph.D.
Packaging tapes are the most widely used pressure sensitive
adhesive tapes with global production in excess of 10 billion sq. meters per
year. Their primary application is corrugated carton closure. Since carton recycling
is a well established practice, two questions arise; first, does the tape interfere
with the recycling of the cartons; second, should or can the tape be recycled?
Comprehensive studies have shown that polypropylene box sealing tapes do not
appreciably interfere with the carton recycling process and that tape residue
from the process may be recycled by means of incineration with energy recovery.
Environmental issues have become increasingly important in
much of the industrialized world over the last third of the 20th
Century. These concerns are now new: citizens of classical Greece worried about
deforestation well before the birth of Christ. Yet the immediacy of modern times
with high energy consumption, increased emissions from manufacturing and agriculture,
and an expanding human population seems to intrude across most aspects of society
and has weighed heavily in major political campaigns. In fact, contrary to commonly
held views that environmental issues are technical or scientific in nature,
they are primarily political with a strong economic flavor. While science can
provide regulatory guidance and solutions, at least partial, to some problems,
the issues are ultimately resolved in the arena of the political economy.
That is why words, with their power to define and deceive,
become very important. What is meant by environmentally friendly, environmentally
benign? What is recycling? What is the public interest?
The world of packaging with concomitant food safety and municipal
solid waste issues is even more subject to an Orwellian future since almost
every9one has experience with packaged goods and has an opinion. Terms like
degradable, biodegradable, recyclable, recycled, natural, safe, reusable, etc.
are often found on packaging without clear definition. Europe, particularly
Germany, has focused on packaging waste with a wide range of regulations and
For the scientist or engineer working in the area of environmental issues,
a balanced perspective is invaluable, one that recognizes that some concerns
are well placed and that some practices are clearly inimical to health and safety
and that others are less so and some even may result from the elevation of environmentalism
to a modern secular religion where belief replaces dispassionate factual analysis.
A number of reputable organizations and individual writers
have attempted to provide conceptual frameworks for analysis and resolution
of environmental concerns. These usually involve the doctrine of life cycle
assessment (LCA) to provide guidance LCA accounts for total emission and total
energy consumption over the lifetime of a product. A good early example was
that of Hocking (1) which compared polystyrene with paper beverage containers
for single use. Contrary to the perception that paper drink containers are environmentally
"friendly", it was found that the production, use, and disposal/recycling of
the paper container required more energy and produced two-and-one half times
more emissions than the plastic container’s life cycle. This principle has been
embodied in life cycle management (LCM) as described by DeSimone and Popoff
(2). Another framework is that of the ISO14000 Environmental Management System
which is the environmental analog of ISO 9000 for quality. More specific to
packaging products are the guidelines provided by the Institute of Packaging
Professionals (IOPP), the Coalition of Northeastern Governors (CONEG), and the
US Environmental Protection Agency (EPA). To sum up briefly they suggest the
following in order of preference:
- No packaging;
- Minimal packaging;
- Consumable, returnable, or resealable packaging;
- Recyclable packaging or recycled material packaging.
Another framework, or actually practice is provided in ASTM
D-1974-94a, "Standard Practice for Methods of Closing, Sealing, and Reinforcing
Fiberboard Boxes," Section 5.6, Environmental Considerations. Since most packaging
tapes are used for these applications it forms an appropriate framework to address
the issue of: "Packaging Tapes: To Recycle Or Not, And If So, How?"
The section relevant to this paper is 5.6 which reads as follows:
5.6 Environmental Considerations:
5.6.1 General - Although the environmental impact of a package is a
component of the package design and evaluation process, the integrity of the
product should not be compromised. Product damage or disposal resulting from
package failure, or both, may well cause greater environmental impact that the
package. Product containment, protection, and preservation, along with consumer
safety, remain the primary functions of the package.
5.6.2 Toxic Content - The use of potentially toxic materials in packaging
components is a concern for their presence in emissions when packaging is incinerated,
or in leachate when packaging is landfilled. Materials used for the closure,
sealing, or reinforcement of boxes shall not have any lead, cadmium, mercury,
barium, silver, arsenic, selenium, or hexavalent chromium which has been intentionally
introduced as a component during manufacturing or distribution as opposed to
the incidental presence of any of these elements. Box closure, sealing, and
reinforcing materials presented in this standard typically meet this requirement.
5.6.3 Solid Waste - Considerations of packaging solid waste involve
the total mass and volume of all package components. The closure, sealing, and
reinforcing components are usually less than 1% of this total. While these materials
are still part of solid waste considerations, emphasis should be on the total.
188.8.131.52 Source Reduction - Reductions in closure, sealing, and reinforcing
materials should be consistent with performance and material requirements specified
in contracts and regulations and with good engineering practice.
184.108.40.206 Reuse - Closure, sealing, and reinforcing materials which allow
the reuse of fiberboard boxes are encouraged.
220.127.116.11 Recycling - Efforts should be focused on maximizing the reuse
and fiber recovery of fiberboard boxes. One consideration in the choice of a
closure, sealing, or reinforcing material should be compatibility with the recycling
of old fiberboard containers. Materials should be chosen which can be removed
from a box prior to recycling, removed from the pulper (vessel for dispersing
old fiberboard into pulp slurry), or otherwise removed in the recycling process.
The materials should then be suitable for appropriate recycling, incineration,
or landfill in accordance with applicable regulations. If the materials are
not removable in the recycling process, they should not cause significant reductions
in the properties of the recycled paper or paperboard.
These latter considerations build on the framework provided by CONEG and especially
on implementation of the German "Verpackungsverordnung" (packaging ordinance)
of June 12, 1991 through the German recycling organization RESY which in January
1992 promulgated the following policy: "In Explanation of the Recyclability
of Packaging made of Paper or Cardboard," section 4: "Adhesive tape and stick-on
labels are packaging aids which are not supposed to hinder the recycling process.
This requirement is met when they disintegrate as little as possible in the
slushing phase and can already be completely - which means both the adhesive
material as well as the bearing material (plastic or paper) - separated in the
pulper or in the following sorting phase. In the case of thermal recycling,
the adhesive tape which as been sorted out must not cause any harmful emissions."
Closure Methods for Cartons
The most common means of closing transport cartons are pressure
sensitive tapes; gluing systems including hot melt adhesives, water activated
tape, staples, and non-metallic strapping.
The user/purchaser of transport cartons may wish to evaluate
the closure method for conformance to ASTM D1974-94a. Performance varies amongst
these closure methods and must be evaluated for the intended purpose. Only the
two tape products provide sealing as well as closure. Toxic content is not an
issue unless the closure has been printed or coated with an ink or coating containing
heavy metals though most of these have been phased out. On the matter of source
reduction, Table I is most illustrative with the polypropylene PSA box sealing
tape providing the best source reduction among common closure methods. (3) One
disadvantage with staples and gluing systems is that the box flaps are often
damaged during unloading rendering the container unusable.
The issue of recycling is more complex. It has been well stated,
and this fits nicely with LCA, that: "Recycling in the material sense is only
environmentally sound if there is a net gain in resources. In the case of plastic-based
materials there is usually a larger net gain in resources if waste materials
are burned with energy recovery and then fresh oil used to make fresh plastics,
rather than using fresh oil for energy and re-using the plastic. Overall, 2%
of mineral oil is used to make plastic packaging of all types, and this plastic
packaging still contains typically 95% of the original oil energy." (4) The
first sentence and the words "net gain" are most important. In the instance
of carton closure, ASTM rightly points out that recycling of the carton is to
be emphasized. Recycling of the closure is secondary and the primary requirement
is that the closure not interfere with the carton recycling process or product
In the U.S., approximately 50% of corrugated cartons are recycled.
In Europe it can run as high as 80%. The recycled product is usually fiberboard,
media, or linerboard and may comprise up to 100% recycle fiber content. Depending
on end use, quality criteria vary but, in any case, input material including
contaminants, tramp material, and other packaging components will affect output
quality. Paper recycling processes are designed to handle some level and types
of foreign material. One of the most troubling of these is materials which produce
"stickies." Stickies may be defined as small insoluble suspended particles that
arise in the repulping stage. They vary in composition but are typically thermoplastic
polymeric materials. Since removal of stickies is a challenge, paper recyclers
prefer feed stock low in potential stickies content.
The total global market of PSA box sealing tape is in excess
of 10 billion square meters. As a major manufacturer of plastic film box sealing
tape with a significant share of this market, 3M wanted to be certain that its
products did not pose a problem to carton recyclers. While unpublished studies
conducted in the 1970s indicated that although, the carton recycling process
shredded the tape, the adhesive stayed with the film and the tape pieces were
easily removed from the repulping stage by conventional techniques employed
by the mills, additional studies were undertaken in recent years to test the
validity of that earlier work.
The first tests were laboratory scale using TAPPI UM213 for
repulpability. The hand sheets were comparable to controls.
Next, tests were conducted on pilot scale equipment at the
University of Western Michigan and at Forest Product Laboratory, Madison, Wisconsin
with similar results. The report from FLP concluded "The fact that the adhesive
stays with the backing in your tape product, and that the backing remains largely
intact, means that the tapes do not appreciably interfere with recycling, either
process or product." (3, 5, 6)
As another approach to understanding, a large OCC (Old Corrugated
Container) recycler provided samples of "stickies" from their repulper. They
were analyzed using optical light microscopy and infrared microspectroscopy.
The results are shown in Table II.
None of the samples were consistent with the composition of
3M’s box sealing tapes.
A survey of eight other OCC recycle plants was conducted.
All eight reported that hot melt adhesives were the major contaminant. One reported
plastic tape particles getting through the screening process and into the final
product. Other problems included staples that occasionally would affect valves,
shredded glass fiber from reinforced gum tape ending up in paper fibers, and
asphaltic tape, though not encountered frequently, are a problem.
The survey also asked about the advisability of a water soluble
or dispersible adhesive. Three plants disliked the idea because of potential
build-up in the system or affect on output quality. Three more thought the approach
questionable and two supported the idea.
In order to satisfy the German requirements, tests were also
undertaken at Papier Technische Siftung (Paper Technical Institute) in Munich.
These were reported by Grossman (7) who concluded "Plastic adhesive tapes or
tapes of wet strength paper with a firmly anchored adhesive and a high comminution
resistance are as a rule "recycling oriented" if the pressure sensitive adhesive
coating remains firmly connected with the substrate material. Tapes of this
type do not impair cardboard recycling, since they can be removed from the fiber
suspension by screening at an early stage."
Thus, film backed packaging tapes are deemed suitable for
use in Germany, a nation regarded as having some of the most demanding environmental
What about other closure methods and their affect on OCC recycling?
Table III taken from Sheehan and Gruenwald (8) summarizes the destiny of various
closure materials in OCC recycling. Note that materials listed as removable
may be recyclable by themselves (e.g. blend staples into feedstreams for steel
mills). From an environmentalist's position, one concluded that there is no
perfect closure material in that all are of finite mass and end up someplace.
However, a thorough understanding of the alternatives can help in making choices.
A lack of apparent understanding on the part of the Gummed Industries Association
that had advertised, among other things, that plastic tape must be manually
stripped from corrugated containers before recycling the container, led to a
lawsuit. A Final Consent on Judgement was issued by the Federal District Court
for the Eastern District of New York (9). The decree "permanently enjoined (GIA)
from directly or indirectly making, issuing, circulating, or disseminating any
advertising promotion, representations or other marketing claims which include
in words or in substance any of the following: …" Among the "following" were
the above stated claims and other claims about gummed tape’s supposed environmental
Recycling of Post Consumer Tape
Recycling of corrugated containers is a process with sound
economics. It provides a net gain. The next question concerns recycling of the
closure materials - can they be recycled with a net gain? Looking to the German
experience the answer is "yes", at least in the case of plastic film box sealing
OCC recycling plants produce as a byproduct shredded plastic
box sealing tape and other shreds of plastic which are removed from the repulper.
According to our survey, which was confined to the U.S., five of eight plants
landfilled plastic scrap and three incinerated it. Strict material recycling
would require a complex process to separate, clean, and redensify such material
- hardly a sound economic idea with plastic resin prices as low as they are.
Yet the opportunity for recycling via thermal recycling, i.e. incineration with
electrical energy generated, looks appealing. This is a high-energy content
material and thermal recycling is increasingly attractive. Originally, the German
law required that packaging must in future be recyclable and that the only form
of recycling was to be material recycling (10). This has changed.
First, a 1994 German law permitted energy recovery from waste
at a 75 percent recovery level. Since steam-powered generating plants operate
at no more than 35 to 40 percent efficiency, waste-to-energy was restricted
to gasification, heating of cement films, and for fuel in steel factories (11).
More recently, German law has encouraged thermal recycling,
called "Verwatung" (recovery), by reducing the efficiency requirements to that
of coal, gas, or oil. Accordingly, electrical energy is now generated at several
power plants that utilize fuel pellets made from tape and plastic scrap as part
of the total fuel consumed (12).
Thus, one may think of using crude oil to produce energy but
using it first as packaging materials and aids, and then as fuel. One restriction
imposed on such scrap is that total chlorine content fall below 1%. This is
not a serious problem since the use of PVC in tape products is declining. Might
this use of energy recovery indicate some larger force at work in society to
alter commonly held views about recycling? Perhaps.
An article in the influential New York Times Magazine in 1996
had the title, "Recycling Is Garbage" (13). The lead-in states, "Rinsing out
tuna cans and tying up newspapers may make you feel virtuous, but recycling
could be America’s most wasteful activity." This represents quite a change from
the idea that recycling is some sort of magic bullet that will solve all environment
problems. Another article in The Economist further supports Tierney’s view (14).
A BASF facility is experimenting with energy recovery from waste plastics in
place of gas or oil as a supplemental fuel with sewage sludge (15). Modern combustion
technology with good temperature control drastically reduces objectionable emissions
thus making thermal reycling more viable (16).
With environmental issues a part of our political economy,
what is the future and how best can scientists and engineers affect it?
By working with governmental organizations and standards organizations.
By providing factual information to governmental bodies and
countering irresponsible proposals and arguments.
By considering business activities within the framework of
By designing processes and products to minimize negative environmental
effects as understood through Life Cycle Management. Examples include modified
hot melt adhesives and new products such as stretchable tape which provides
approximately 75% material reduction over stretch film.
By communicating your thoughts to the press and civic groups.
Environmental considerations for products and processes often
go beyond mere technical concerns. Conceptual frameworks such as ISO 14000 provide
overall guidance on such considerations. Recycling of corrugated containers,
clearly an environmentally beneficial activity, is not adversely affected by
plastic film pressure sensitive adhesive tapes used for transport packaging.
The tape scraps resulting from container recycling may best be disposed of through
thermal recycling, an improved technology which is gaining acceptance.
Approximate Mass of Box Closure Materials
Box Closure Material
Polypropylene PSA Box-Sealing Tape
Reinforced Gummed Tape
Description of Particles from OCC Plant
Colorless film fragments
Daran film—90:10 vinylidene choride:methyl acrylate
EVA and rosin ester
EVA and coumarone indene
EVA and rosin ester
Blue sticky material: isoprene/styrene, ethylene,
rosin ester, hydrocarbon resin
Green sticky material: polyethylene, vinyl acetate/methyl
acrylate or methacrylate/styrene similar to Flexcryl 1625
Yellow sticky material: isoprene/styrene, clay,
Light green solid: EVA, rosin ester
Dark blue solid: EVA, rosin ester
Dark green solid: cellulose, amide
Brown solid: long chain ester, possibly degradation
Amber solid: cellulose, amide, phenolic
Green foam: polyether urethane
10. Colorless foam: polyether urethane
11. Polka dot film: clay, styrene, vinyl acetate/acrylate
12. Yellow film: polyethylene, polypropylene, carbonate
13. Blue film shred: Polyethylene, talc
14. Red film shred: polyethylene, polypropylene
15. White film: polyethylene
16. Light blue film: polystyrene
17. Brown fibers: paper (wood pulp)
Fate of Closure Materials
Possible Paper Contaminant
Possible Water Contaminant
Pressure Sensitive Tape
Reinforced Gummed Tape:
M.B. Hocking, Science Magazine, Feb.
L.D. Desimone, F. Popoff, Eco Efficiency, MIT
Press, Cambridge MA, 1997
T.B. Jensen, Adhesives Age, Sept. 1992
Johnson, AFERA Congress Proceedings, Amsterdam,
J.H. Klungness, Private Correspondence, Aug.
J.H. Klungness, L. Gruenewald, M.S. Wu, D. Bormett,
TAPPI Pulping Conference Proceedings, 1992
H. Grossmann, European Tape and Label Conference,
R.L. Sheehan, L.E. Gruenewald, J. of Applied
Mfg. Systems, Spring/Summer, 1997
Minnesota Mining & Manufacturing Co. v.
The Gummed Industries Association Inc., U.S. District Court, Easter District
of New York, Civil Action No. 92 Civ 5555 (ADS), Jan. 27, 1993
10. T. Rummler, W. Schott, The German Packaging Ordinance: A Practical
Guide with Commentary, Perchard Assoc., St. Albans, UK, 1992
11. T.B. Jensen, Packaging Technology and Engineering, Oct. 1995
12. H. Korfmacher, Private Communication, Sept. 1997
13. J. Tierney, The New York Times Magazine, June 30, 1996
Economist, p. 63, Oct. 18, 1997
15. J. Brandrup, M. Bittner, W. Michaeli, G. Menges, Recycling and Recovery
of Plastics, 8.14, Hansen, New York, 1996
16. T.B. Jensen, AFERA Congress Proceedings, Florence, 1990
Other Technical Notes