INK AND CLEANER WASTE REDUCTION EVALUATION
FOR
FLEXOGRAPHIC PRINTERS
by
Gary D. Miller and William J. Tancig
Hazardous Waste Research and Information Center
Champaign, Illinois 61820
Michael J. Plewa
University of Illinois at Urbana-Champaign
Institute for Environmental Studies
Champaign, Illinois 61820
Contract No. CR-815829
Project Officer
Paul M. Randall
Pollution Prevention Research Branch
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268
RISK REDUCTION ENGINEERING LABORATORY
POLLUTION PREVENTION RESEARCH BRANCH
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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NOTICE
The information in this document has been funded by the U.S. Environmental Protection Agency
under the auspices of the Waste Reduction Innovative Technology Evaluation (WRITE) Program under
Contract No. CR-815829 to the Hazardous Waste Research and Information Center. It has been
subjected to the Agency's peer and administrative review, and it has been approved for publication as
an EPA document. Mention of trade names or commercial products does not constitute an
endorsement or recommendation for use.
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FOREWORD
Today's rapidly developing and changing technologies and industrial products frequently carry with
them the increased generation of materials that, if improperly dealt with, can threaten both public
health and the environment. The U.S. Environmental Protection Agency is charged by Congress with
protecting the nation's land, air and water resources. Under a mandate of national environmental laws,
the agency strives to formulate and implement actions leading to a compatible balance between human
activities and the ability of natural systems to support and nurture life. These laws direct the EPA to
perform research to define our environmental problems, measure the impacts, and search for solutions.
The Risk Reduction Engineering Laboratory is responsible for planning, implementing, and managing
research, development, and demonstration programs to provide an authoritative, defensible engineering
basis in support of the policies, programs, and regulations of the EPA with respect to drinking water,
wastewater, pesticides, toxic substances, solid and hazardous wastes, and Superfund-related
activities. This publication is one of the products of that research and provides a vital communication
link between the researcher and the use community.
This document present the results of an experiment conducted to quantitatively compare the
volume and toxicity of wastes generated during flexographic printing and released as gaseous, liquid
and solid wastes, before and after switching to water-based inks and a detergent cleaner, and the
economic impact resulting from modification of a traditional printing technology.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
ill
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ABSTRACT
This report describes the technical and economic effects incurred by a flexographic label printer
who changed the type of ink and cleaning agent used in its print shop. The changes were incurred as
the best way to eliminate all hazardous materials. The company's corporate management mandated
the switch out of concern for its employees, and with the intention of limiting possible future waste
liability. Hence, the traditional alcohol-based inks and alcohol solvent cleaning agents gave way to
water-based inks and an aqueous cleaner.
From a technical point of view, there is general agreement in this shop that the water-based inks
yield better quality labels. Labor is reduced largely because the water-based inks are more easily
removed from the pans, rollers and plates. Ink splashes and spills are also quickly removed by
sponging either with water or the aqueous cleaner.
As a result of these process modifications, solvent emissions to the plant air have been reduced
about 80%. The toxicity of the gaseous and liquid wastes have also been reduced by approximately
90%. Hazardous liquid wastes have been eliminated while wastewater sent to the sanitary sewer has
increased. Solid wastes have remained relatively unchanged.
From an economical point of view, major savings develop with water-based inks at the studied
facility because the majority of the liquid wastes do not require disposal as hazardous agents. The inks
are presently acceptable to this locations local public waste treatment plant, and the cleaning towels
and wipers are now either rinsed within the plant or sent to a commercial laundry. Formerly they had
to be labeled as hazardous and segregated for special disposal. Though untreated ink washes are
acceptable to the waste treatment plant, the company has chosen to filter theirs through a special
absorbent to remove all color. The used absorbent is acceptable in the local landfill.
These changes, at least for this company, involved no capital expenditures. With the levels of
various alcohols evaporated during printing now greatly reduced, the employees enjoy a cleaner and
healthier plant environment.
This report was submitted in partial fulfillment of Contract No. CR-815829 by the Hazardous Waste
Research and Information Center, under sponsorship of the U.S. Environmental Protection Agency.
This report covers a period from September 1989 to December 1992, and work was completed as of
19 December 1992.
IV
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CONTENTS
Foreword iii
Abstract iv
Figure vi
Tables , vii
Acknowledgement ix
1. Introduction 1
General project background 1
Printing process background 2
Waste reduction in printing 4
2. Conclusions and Recommendations 7
3. Methods and Materials 10
On-site testing 10
Degree-of-Hazard 13
Economics 14
4. Results 16
On-site testing 16
Degree-of-Hazard 21
Economics . . 26
5. Quality Assurance 28
References 29
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FIGURE
Number Pace
1 Single print station schematic for flexographic printing 3
VI
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TABLES
Number
1 Comparative solvent loss to air from using water-based inks .......... . ......... 7
2 Methods used for estimation of emissions ....... ......................... 10
3 Composition of inks tested as reported by the manufacturers
4 Composition of cleaners tested as reported by the manufacturers ...... . ........ 13
5 Toxicity conversion factors .................................... ' ...... 14
6 Summary of cost comparison factors evaluated .................. .......... 15
7 Ink used and estimated emissions ..................................... 17
8 Weight loss data from laboratory evaporation at 70°C .................... • • • 17
9 Estimated air and water emissions at MPI Label Systems for test run with green labels
and water-based ink and cleaner ........................ • • • • ......... 1 8
10 Estimated air ifid water emissions at MPI Label Systems for test run with green labels
and alcohol-based ink and cleaner ........................... ......... 19
1 1 Estimated air and water emissions at MPI Label Systems for test run with purple labels
and water-based ink and cleaner ..................................... 20
1 2 Estimated air and water emissions at MPI Label Systems for test run with purple labels
and alcohol-based ink and cleaner ........................... ......... 21
13 Degree-of-Hazard analysis for MPI Label Systems green alcohol-based ink and
cleaner, liquid waste ..... . ....................................... 22
1 4 Degree-of-Hazard analysis for MPI Label Systems purple alcohol-based ink and
cleaner, liquid waste ................................. • • • ......... 23
1 5 Degree-of-Hazard analysis for MPI Label Systems green alcohol-based ink and
cleaner, air emissions ............................................. 23
VII
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Number Page
16 Degree-of-Hazard analysis for MPI Label Systems purple alcohol-based ink and
cleaner, air emissions 24
17 Degree-of-Hazard analysis for MPI Label Systems green water-based ink and
cleaner, liquid waste 24
18 Degree-of-Hazard analysis for MPI Label Systems purple water-based ink and
cleaner, liquid waste 25
19 Degree-of-Hazard analysis for MPI Label Systems green water-based ink and
cleaner, air emissions 25
20 Degree-of-Hazard analysis for MPI Label Systems purple water-based ink and
cleaner, air emissions 26
21 Summary of evaluation of annual costs and savings 27
viii
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ACKNOWLEDGEMENT
The U.S. EPA and the Hazardous Waste Research and Information Center acknowledge Don Gray
of MFM Label Systems who arranged the use of the printing presses for testing.
Fred Shapiro of the Flexographic Technical Association (FTA) and Gary Jones of the Graphic Arts
Technical Foundation (GATF) are acknowledged for reviewing the drafts of this report.
ix
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SECTION 1
INTRODUCTION
GENERAL PROJECT BACKGROUND
This final report is part of the Illinois/EPA WRITE (Waste Reduction Innovative Technology
Evaluation) Program. The project was done in cooperation with MPI Label Systems, University Park,
Illinois, a narrow-web flexographic printing firm. The purpose of the project was to quantitatively
compare the volume and toxicity of any waste generated during printing and released as gaseous,
liquid and solid wastes, before and after switching to water-based inks and a detergent cleaner, and
the economic impact resulting from modification of a traditional printing technology.
*
Two main modifications in the printing practices of this company were examined in this project:
I. Water-based inks were substituted for alcohol-based inks.
2. A detergent cleaning solution was substituted for alcohol solvent cleaners.
The work was a joint effort of MPI Label Systems; the Hazardous Waste Research and Information
Center which is a division of the Illinois Department of Energy and Natural Resources, Champaign,
Illinois; and the Pollution Prevention Research Branch of the U.S. Environmental Protection Agency's
Risk Reduction Engineering Laboratory, Office of Research and Development, Cincinnati, Ohio.
All site testing was conducted in the University Park, Illinois printing plant of MPI Label Systems,
Inc. The plant is one of eight operated by the parent corporation in the United States. The company
specializes in narrow-web flexography to produce a wide variety of labels. MPI has been in operation
at the current site since 1988, having moved from an older nearby location. Its facilities are housed
in a modern one-story, clear-span building of about 15,000 square feet. Half of the building is used
for storage of supplies, and the other half for administrative offices and actual printing operation.
Several of the press lines have the capacity to print up to six colors per label. Each line is operated
by an individual who is responsible for all steps of a complete label run under direction of the press
room supervisor.
The opportunity to conduct this evaluation came about as a result of the parent corporation's 1988
decision to eliminate, as quickly as practical, every toxic and hazardous material then in use. Part of
the motivation for this action was corporate concern for its employees, primarily due to daily exposure
to ink alcohol fumes in the work area. Another concern was a desire to avoid future liability and
litigation resulting from legislation, which might limit the use of chemicals. ,
}
The first step evaluated and the most significant, was the conversion to water-based inks from
alcohol-based inks. A related development instituted primarily for technological improvements but
which also reduces the amount of waste, was the substitution of plastic printing plates for the older
type rubber printing plates. Water-based inks did not produce satisfactory images with rubber printing
plates. The amount of waste is also reduced due to newer and better plates in operation.
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The project's second step was to study elimination of alcohol-based press-cleaners. Before this
change, the cleaner-and-ink soaked press wipers required classification and disposal as hazardous
waste materials, which was a relatively expensive handling and disposal operation. Initial project plans
included evaluating the potential of replacing the alcohol-based cleaners with a terpene-type (d-
limonene) cleaner. However, just prior to commencement of the in-plant measurements, MPI began
examining some of the new aqueous cleaning agents which had recently become available on the
market. These ranged from standard industrial detergent cleaners to newly-formulated terpene-
surfactant solutions. This aspect of their operation continues to be one of periodic reevaluation as
more satisfactory cleaners become available. Although MPI Label Systems now does its press cleaning
with a single dilute aqueous solution of detergent (this is the cleaner examined), it is prepared to test
any promising product.
PRINTING PROCESS BACKGROUND
The Printing Industries of America estimates approximately 57,000 printing, publishing and related
facilities now operate within the United States. Of these, about 40,000 are commercial printers. The
remainder according to a discussion with the Printing Industries of America include newspaper and
magazine publishers, photocopiers and in-house printers (January 22, 1991). The five most common
printing processes in order of their market share and volumes of ink used are lithography (also called
offset), gravure, flexography, letterpress and screen (1). Flexographic printing derives its name from
the flexible, roll-mounted printing plates characteristic of the system, as opposed to the less-flexible
metal printing plates traditionally used in other printing methods. Presses are also categorized
according to whether they print on individual sheets, called sheet-fed, or on a continuous roll, called
web, of paper or other substrates.
The most recent industry survey by the Flexographic Technical Association (FTA), 1989 states that
over 4,000 U.S. printing plants utilize more than 22,000 narrow-web flexographic presses (2). These
plants employ about 150,000 individuals, and generate about $4.5 billion annually of product. Annual
growth rate during the past decade is estimated to have been 3% - 5%.
The 600 year old printing technology follows certain well-defined steps. It begins by deciding to
reproduce an image, whether text or illustration. The substrate upon which the image is to be
reproduced must be selected, (e.g. paper, cardboard, plastics, fabric, metal, glass, etc.). That
substrate must then be obtained in adequate quantity and quality. The color of the image to be
reproduced requires that suitable inks be secured. Depending upon the particular printing process, the
ink must be formulated to have an acceptable viscosity, or rate of flow, and the correct color imparted
to it by resident pigments. The latter are usually opaque, insoluble materials, finely ground to
submicron size before being incorporated into the mixture. Pigments are usually soluble colorants that
are used to color fabrics, water colors, and some stains.
The image to be reproduced by printing must be developed into a form, usually called a plate,
suitable for printing. If the image is to be printed in only one color (black ink on white paper, for
example), then only one print image needs to be made. For each color needed, an additional print
image is necessary- These images are made by various processes on various types of metal, wood,
stone, rubber or plastic plates. Originally, most print faces or plates were carved by hand, and special
art work is still done that way.
Within the printing industry, the most common plate making process begins with a photographic
negative of the image to be reproduced. For some printing processes the photo negative can be placed
directly on the photosensitive material intended to constitute the finished plate. This material sandwich
(negative on plate material) is exposed to an intense light during which the exposed portions (those
beneath the clear areas of the negative) of the plate will harden and be impervious to the washing
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inherent m the development process. Any unexposed areas are dissolved by a plate developing
solution.
Once an acceptable printing plate is approved by the customer, it is positioned in the printing press,
usually by forming around a roller. Ink of the proper color in a reservoir is made continually available
to a series of rollers which forms an ink film of the proper thickness for application to the plate. The
ink on the plate is eventually transferred to whatever substrate is being used. If more than one color
ink is required then each color will be applied sequentially. The ink dries in place, either by
evaporation, absorption, oxidation or polymerization of its oils and solvents, after which the final
printed product is readied for distribution. The common printing processes described previously
accomplish each step in different ways. However, regardless of the different printing processes and
different intermediate steps utilized by the printer, the final results tend to be much the same.
Figure 1 is a simplified schematic of a single flexographic print station. Ink in the reservoir is picked
up by a roller. The roller contacts at least one additional roller to develop an evenly distributed ink film
of ideal thickness for transfer to the plate which will make impressions of the first image. The
substrate paper in this study is pressed against the printing plate by another roller to ensure the plate's
ink impression will be uniform. Rollers are used so the entire process can be continuous. After passing
through each station, the newly printed materials move into a drying station. In a matter of seconds,
the ink dries. Each station contains heaters to maintain a temperature of approximately 70°C.
~^\
Dryer
Die
Cutter
O n
Was
^_
c**\ c
Paper
kStock
Q
Finished
Labels
Ink Pan
Figurei 1.
Single print station schematic for flexographic printing
The printing station shown in Figure 1 is limited to a single color ink. Multicolor printing simply
places additional printing stations in series, each station applying a different color. These printing
stations are referred to collectively as a single printing press.
Depending on the type of material receiving the plate's impression, and the customer's desire, the
dry printed surface may be coated with a gloss varnish or plastic to protect it in the last station. After
the final station, and separation from the excess material around the printed area, the completed labels
are wound onto a roll. The speed at which paper is fed through the press can be varied, depending
on the label size, ink type, precision of the press and skill of the operator.
. Within the flexographic printing industry, press types are classified as narrow-web and wide-web.
Narrow-web is typically used to print tags, labels and some packaging. Wide-web presses are used
for envelopes, plastic bags, newspapers and wall paper.
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Paper stock for printing labels flexographically, the popular system for printing labels in the United
States is made of two-ply material (3). The bottom ply consists of silicone-treated paper. The top ply
is the paper on which the labels are printed, and is adhered to the bottom ply. The top ply peels away
from the silicone treated bottom ply. After printing and drying, each label is "parted" or readied for
removal from the parent paper web. Each label's perimeter is cut-out by a steel cutting roller. The
parting roller, working to very close tolerances, cuts through the single top ply of j paper to separate
the finished label from the surrounding unprinted stock. This stock waste is peeled away automatically
onto a separate roll for disposal, usually by shipment to a landfill. The bottom ply, with adhering
labels, is made up into rolls of a specific label count for each customer, then packed and shipped.
Customers will remove and apply the finished labels either automatically or manually. The silicone-
treated base ply, from which the labels are removed by the customer, is usually disposed of in a landfill
or by incineration, according MPI Label Systems.
i
According to a discussion with the Graphic Arts Technical Foundation, typical flexographic ink
incorporated the following: a resin, to provide adhesion and to help disperse the pigment; a solvent,
to control viscosity and drying rate; a plasticizer, to soften the resin; occasionally a lubricant, to control
the coefficient of friction; and a defoamer, to limit foam formation in the ink reservoir (December,
1989). Suitable resins for aqueous inks include shellac, soya protein, casein, acrylic copolymers, and
emulsions of iatex. Acceptable solvents are lower-molecular weight aliphatic alcohols, esters such as
ethyl acetate, glycols, and, of course, water.
Finally, a pigment is added to provide the necessary color. Typical flexographic pigments are:
titanium dioxide and kaolin clay for white; carbon black and ferrous oxides for yellow, red and black;
various azo compounds for yellow and red; and phthalocyanine derivatives are valuable for blues and
greens.
i
MPI Label Systems' water-based inks contain organic chemical pigments, an emulsifier (1 %), an
acrylic resin thickener (20%) similar to that found in water-based house paints, up to 5% of isopropyl
alcohol, 1 % of ammonia and 50% - 65% water. The inks used do not contain heavy metals.
Eiecause the cleaning agents used most frequently by printers are often composed of organic
solvents, the majority of wiping materials used as sponging pads are classified as hazardous waste and
disposed of in hazardous waste landfills at a relatively high cost. At MPI Label Systems the fiber
wipers, previously used with the alcohol based rags and cleaners, have been abandoned in favor of
fabric shop towels which, after use, are laundered and reused, resulting in additional savings.
WASTE REDUCTION IN PRINTING
Printing produces waste at every step. Solid and liquid wastes generated in plate production
include: damaged plates, developed film, photographic chemicals, silver (most printing operations
recover the silver), and plate-developing solutions. Spent photoprocessing chemicals are generally
regarded as being biodegradable and are usually discharged to the sewer. Depending on the specific
materials used, some volatile solvents may also be released to the air as part of image making and
plate processing.
During the printing process, volatile solvents in the inks (e.g., aliphatic alcohols and ketones, and
aromatics) and cleaning solutions are released to the air. Most of the ink solvents are evaporated
during the drying process, though some are absorbed by the treated paper surface. The type and
amount of solvents released depends on the ink formulations and the area of surface printed. Point
source control technologies such as catalytic or thermal incineration have been installed in some plants
to capture solvent releases (4-7). '
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Waste inks diluted with cleaning solvents are the primary liquid wastes generated in the printing
process. Most inks can be recycled, e.g. by blending to make a black ink. Waste links that contain
hazardous organic solvents must be classified as hazardous wastes and either incinerated or distilled
to recover the solvent. Small amounts of lubricating oils are the other liquid waste that is generated
from operation of the printing presses. This used oil has the potential to be recycled (5).
A wide variety of cleaning solutions are used by printers. These flexographic cleaners can contain
volatile organic chemicals such as toluene and naphtha. In those cases where the solvents are
absorbed on fabric towels for handling by a commercial laundry, it may be necessary for the printer
to generate the documentation required for hazardous wastes, and the launderer will be required to
provide the documentation required of a hazardous waste treatment plant. Consequently, finding
suitable nonhazardous substitute solvents could save considerable effort and expense for both parties.
Waste paper is the main solid waste generated in printing. The paper consumed as waste during
a flexographic label setup is largely a function of the press operator's experience and training, the
accuracy of the artwork, and the condition of the press (i.e. number of inks required and size of the
label). Operators try to use paper stock of such a width as to minimize trim waste. Other solid waste
produced includes empty ink containers and cleanup rags or wipes. Some printers dispose of their rags
in the trash while others have the rags laundered for reuse. The sludge produced in the rag cleaning
process contains the materials removed including inks, cleaners, oil, dirt and other contaminants. This
sludge almost always requires disposal as a hazardous waste (5).
Options for reducing waste generated by printers have recently been reviewed for three cases by
the State of California and the USEPA (8,7). Methods for waste reduction in materials handling and
storage, image processing, plate making, printing, and finishing have been listed. Techniques which
can be used to reduce waste during printing include using less hazardous inks and cleaners, plus
generally being more careful during setup and cleaning. Waste solvent-based ink was reduced in one
case by spraying a protective coat over the ink in the reservoir at the end of each day. As a result,
waste ink was reduced by five pounds per day. Thus, less waste ink would need to be disposed of
and less new ink purchased. The total operating savings in this specific case were estimated at
$3,375 per year for this technique (8). Spraying inks surfaces when not in use is a standard procedure
in many shops. Techniques for reducing waste paper in web operations include installing break
detectors and automatic splicers. Waste paper can never be entirely eliminated. An emphasis on
recycling is also necessary. However, as noted in MPI Label Systems' case, the waste paper may have
adhesives or other coatings that exclude it from reuse.
Changing to less hazardous inks is not always straight forward, though recent advances in
formulations have overcome many limitations. Water-based inks theoretically require more energy to
dry than solvent-based inks. This requirement has not been shown to be of any significance in this
project printing on paper since the heater and drying chamber for each ink color is adequate to
compensate for the additional energy requirements; however, this may be significant when printing on
films and foils.
With modern water-based flexographic inks, many label types can be run up to 10% faster due to
improved press design (i.e. dryers, etc.). Other reported limitations of water-based inks such as
requiring more frequent equipment cleaning and tending to cause the paper sheets to curl have been
overcome by improved formulations. Many water-based inks also have acceptable; gloss but appear
to be low-gloss due to absorption on the paper, though this can be overcome by using an overcoat or
printing on a varnish undercoat. Another alternative which can reduce solvent emissions is the use
of ultraviolet (UV) inks which set or harden when exposed to UV light rather than by evaporation. The
disadvantages associated with UV ink include higher ink cost, the need for special equipment, exposure
of personnel to UV light, and the toxicity of some of the ink chemicals. Electron-beam-dried inks are
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also available that contain no solvents, but operator protection from X-rays used in the process is
required and the system often degrades the paper (5).
A case study of switching from alcohol-based to water-based inks on low density polyethylene film
a flexographic printer was presented by Makrauer in 1987 (9). He reported considerable difficulty in
making the conversion. Technical problems included pH control for the ink, a need to modify the
drying equipment, ink metering modifications and increased roller wear. All problems were gradually
overcome through improved ink formulations, experimentation, and facing the rollers with more durable
materials. Makrauer also reported that cleaning water-based inks was more difficult. Benefits of
water-based inks at that time were reduced air emissions, less toxic liquid wastes, improved color
control, greater coverage yield, and improved working conditions due to reduced alcohol vapors.
Quantitative measurements of emissions and other wastes generated when using alcohol-based inks
compared with water-based inks were not reported. A discussion with the Flexographic Technical
Associated on the quantitative evaluation of the benefits of using water-based inks in flexographic
printing elicited their opinion that there probably are no significant economic advantages (March 1991).
For example, both ink types cost about the same, and while some printers report faster printing is
possible in some instances, others point out that presses must be slowed for some water-based
materials. If there is an overwhelming economic advantage to be achieved with water-based inks, it
will probably be due to the elimination of various hazardous wastes.
The introduction of water-based inks in printing on plastic materials via flexograpny had some early
problems using the same technology for newspapers. The developments made by the newspapers
have helped all flexographic operators. In several installations, the print line and ink supply lines have
been designed to literally eliminate ink wastes. Excess ink and ink washings are collected in a holding
tank and used to dilute new inks to the proper viscosity. This type of ink management is the same
whether water-based or solvent-based ink is used at the facility. This closed-cycle system does not
reduce the paper wastes, and relies on a continual demand for black ink. Although none of these
newspapers have published an economic comparison of the old versus the new system, private
discussions with plant managers confirm each plant is producing a better product at less cost.
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SECTION 2 !
CONCLUSIONS AND RECOMMENDATIONS ;
The change from alcohol-based inks and cleaners to water-based inks and a detergent cleaner has
resulted in less quantity and toxic waste being generated at MPI Label Systems. However, there were
some trade-offs such as elimination of hazardous wastes but generation of wastewaters discharged
to the sewer. As with most changes in processes, the switch in materials, including changing the type
of plate used, required many adjustments and fine-tuning. Also, during the past two years advances
have been made in the water-ink formulation so these inks are easier to clean, and the rate at which
labels can be printed has increased. The cooperative approach developed between industry and
government in this project, and the comparative methods, described in later text, can be used to
evaluate the environmental and economic benefits of other similar product substitution projects.
The amount of solvent emissions to the air was reduced by over 80% per run as a result of
changing inks and cleaners according to the measurement taken at MPI Label Systems. In addition,
the components emitted (primarily water) are considerably less toxic to the press operators and the
environment than were being emitted from the alcohol-based inks. Since MPI Label Systems uses
approximately 1,800 pounds of ink per year, an estimate can be made of the total weight of solvent
emissions they currently release and what would be released if they were still using the alcohol-based
inks. This comparison is shown in Table 1 for MPI and by extrapolation to the entire flexographic
industry in the United States.
TABLE 1. COMPARATIVE SOLVENT LOSS TO AIR FROM USING WATER-BASED INKS
Ink type MPI Label Systems, Inc. Entire Industry
Alcohol Inks 927 Ibs/yr solvents 153,900,000 Ibs/yr solvents
Water-based Inks 185 Ibs/yr solvents 29,240,000 Ibs/yr solvents
Total Solvent Reduction 787 Ibs/yr solvents 124,660.000 Ibs/yr solvents
For this estimate the laboratory evaporative loss percent for black ink, as determined in this study, was
used. If the entire industry would require 300 million pounds per year of waster-based inks; then for
the entire industry 125 million pounds per year of toxic solvents would no longer be emitted.
Additionally, zero air toxics are being released from MPI Label Systems' new detergent cleaner as
opposed to the hazardous material previously released from their solvent cleaner. Although hazardous
wastes have been eliminated at MPI Label Systems, the total waste situation is not completely
improved. For example, aqueous wash liquids discharged to the sanitary sewer have increased from
the volume required for simple housekeeping and personal needs to at least an additional 7,800 gallons
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per year. Solid wastes generated in the form of wasted labels, wrap, trimmings and other paper have
remained about the same.
The water-based inks were estimated, to reduce the relative toxicity of the liquid and air waste
stream. A significant 10 fold reduction in the equivalent toxic concentrations for both the liquid
wastes and air emissions was found compared to the alcohol-based products.
As a consequence of switching inks and cleaners, MPI Label Systems estimates an annual cost
savings of at least $16,500 per year. In addition to the above dollar advantages accruing from use
of water-based inks and a relatively harmless cleaner, it is the opinion of MPI Label Systems plant
manager and shop superintendent that MPI Label Systems is also realizing the following subjective
benefits:
I., Water-based inks are easier to clean from pans, plates and rollers;
2. Water-based inks waste is more easily disposed of;
3. Water-based inks spills are easier to clean up when wet; ,
4. Water-based inks waste material that is going to a landfill does not have to be classified by
MPI Label Systems as hazardous, thus reducing long-term liability;
5. Water-based inks do not require expensive solvents for cleanup; and
6i. Employees are enjoying a cleaner, safer work environment.
During the planning stages of this project it was intended to quantitatively measure ink and cleaner
usage at every step of the printing process. After a preliminary run it became apparent that several of
these measurements would be very difficult to carry out. Two examples are worth noting. Rrst, it
was intended to determine by weighing the amount of dry ink actually deposited on labels. This was
to bo accomplished by weighing approximately 1000 blank labels as they came from the press,, and
1000 printed labels. After numerous measurements, at least for the labels measured, it became
obvious that the amount of ink on anything but a very large number of labels is negligible. It appears
that variations in the paper weight and, perhaps, non-uniform thickness of the adhesive film are much
greater than the amount of ink applied. Second, the amount of ink wasted on the paper trimmed from
around each label was to be measured. The trimmed top layer with adhesive backing is peeled away
from its paper base, then collected as a roll of waste. Since each layer sticks to trie preceding one it
was not possible to separate individual layers of the trimmings from each other to weight an known
number of trimmed labels.
The result of these two experiences was that the ink reservoir was weighed before and after a run
and the difference was considered due to all ink uses - labels, trim waste, spills, cleanup of the ink
pans, rollers and printing plates. With the exception of the ink lost during cleanup (and on a relatively
short run this will represent most of the ink used) the balance will have lost its solvent content to the
shop air.
A lesson learned during this project is the importance of a pre-testing agreement for all planned
plant tests with the company personnel involved. In this case, prior to collecting in-plant
measurements, several label runs were closely observed to learn the various steps, materials, etc., to
be encountered. However, by the time measurements were taken, the plant had made significant
changes in some of their procedures. MPI Label Systems staff continuously evaluate new inks,
cleaners and other materials from vendors. Ink manufacturers are frequently improving their
formulations. During a six month period, MPI Label Systems changed ink suppliers at least twice and
evaluated several new cleaners. As better materials and less expensive procedures become available
that will maintain or improve quality while reducing costs, almost any process change will be
considered by this facility. Thus, the experimental plan had to be modified and the results including
various cost factors were not static.
8
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It should be kept in mind that the scope of this evaluation was limited in several important aspects.
The image and plate making steps were not included in the evaluation of waste produced since the
plates used at the MPI Label Systems plant are produced by another company. The wastes generated
while formulating inks and cleaners were not comparatively evaluated, and the impact of using water-
based inks on the recyclability of the product labels was not evaluated in this study.
MPI Label Systems and the entire flexographic printing industry are benefiting economically, in the
quality of the printed product, and in employee health and safety by changing from solvent-based to
water-based inks and cleaners. The environment is also benefitting. Additional benefits will be realized
as the use of solvent-type industrial cleaners is increasingly phased out. Label customers are also
benefiting from the change in technology with better quality labels being produced.
-------
SECTION 3
METHODS AND MATERIALS
ON-SITE TESTING
Solvent loss by emission from the inks was estimated by a combination of approaches including
materials use measurements during two print runs, laboratory measurement of alcohol evaporation from
the two types of inks, and calculations based on the reported composition of the inks. The methods
used to compare emissions from the two ink types are summarized in Table 2.
TABLE 2. METHODS USED FOR ESTIMATION OF EMISSIONS
Type of ink
Water-based
Alcohol-based
Materials use
in plant
X
Evaporative loss
laboratory
X
X
Ink composition
calculation
X
X
Since MPI Label Systems no longer uses alcohol-based inks, and no longer permits their use, it was
not possible to measure actual emissions during in-plant use of alcohol-based inks. However, the
volume of alcohols evaporated from the two types of inks during a printing run can be calculated from
known ink formulations if the total amount of ink used is known, in-plant measurements of ink and
cleaner usage were taken for two single-color printing runs to obtain an estimate for variability.
For the materials balance method, the weight of ink used during each printing run, A, was
calculated by weighing the various items before and after the printing runs using the following formula:
A = (B + C)-(D + E + F) ! (1)
where B = weight of ink in reservoir and weight of reservoir at beginning
C = weight of water and other materials added during run
D = weight of ink remaining in reservoir and weight of reservoir at end of run
E = weight of ink retained in the ink pan, and on the gaskets, at end of run
F = weight of ink lost by spilling
10
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Mass measurements were taken on an electronic balance (capacity: 12 kgs, ±, 0.1 g) which was
transported to the printing site. The percent solids, S, of both ink types and cleaners were determined
gravemetrically in the laboratory by drying known weights in triplicate (approximately 10-15 grams
each) of ink samples in a rotating device to maintain a thin ink film. The drying temperature was 70°C
as maintained on each press. Then the percent of volatile materials, V, was calculated by simple
subtraction:
V = 100-S (2)
Laboratory measurements of the percent solids, S, for each ink were used to estimate the total
weight of ink, Q, retained on all the labels (acceptable and waste) working from the total weight of
ink used. A, as follows:
Q = AxS/100 " (3)
The amount of ink on waste labels, G, was then estimated by the proportion of total labels printed, H,
to good labels sold as product, K.
G = Q x (H - K) / H (4)
The weight of volatiles in each ink determined gravimetricaily in the laboratory was compared with
the values reported on the material safety data sheets. This information is shown in Table 3. Both
inks have similar amounts of total volatiles. The alcohol-based ink contains six volatile components,
four of them alcohols. Ethyl alcohol and isopropyl alcohol are present in the largest amounts. By
comparison, the water-based ink contains four volatile components. Most of the volatiles are water
and isopropyl alcohol. Some of the water is bound to the resins and does not evaporate upon drying.
According to a discussion with the Flexographic Technical Association this amount of water is around
24% (March 1991). Both the solvent cleaner previously used and the detergent cleaner now in use
contain over 97% volatiles. The volatiles from the solvent cleaner were hazardous while the detergent
cleaner volatiles are nonhazardous. The relative compositions of cleaners tested as reported by the
manufacturer are presented in Table 4.
The amount of ink and cleaners produced as liquid waste was determined gravimetricaily for the
two printing runs. No liquid ink wastes were sent to the sanitary sewer prior to using water-based
inks. The alcohol-based waste ink had to be disposed of as a hazardous waste and thus manifested
to a landfill. Currently these types of wastes can no longer be landfilled and are usually incinerated
or recycled. While the total amount of waste manifested in a year is on company record, this
information was considered proprietary and was not made available for the project. Nor was it possible
(because of the company ban) to directly measure the amount of liquid alcohol-based ink that would
have been used for printing runs similar to those evaluated with the water-based inks. Company
officials reported that, in their experience, the amount of solid and liquid wastes generated are
essentially the same for the two types of inks. The main difference is that liquid wastes from the
water-based ink do not have to be disposed of as a hazardous waste.
Currently, each printing line maintains a 50 gallon drum of water for use in disposing of ink wastes.
At the end of each printing run, the ink reservoirs are rinsed in these drums. Each drum is emptied
eveiy week into a commercial ink filtering device called an Ink Splitter. This unit absorbs the colored
pigments on cellulose fibers, and the slightly grayish filtrate is run to the sewer, as approved by the
local treatment plant. The colored absorbent is acceptable in landfills as non-hazardous material. The
concentration of ink and cleaner components that would be in this facility's effluent was estimated
assuming ink wastes on the press rollers, pans and plate are removed by scrubbing with a brush and
fabric town wetted with an aqueous detergent solution. This quickly removed the ink residues. The
11
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rollers, pans and plates are then dried with another fabric towel. The towels are rinsed in the barrel
of water at each press, then sent to an industrial laundry service for cleaning. By appearance, a
negligible amount of ink was retained by these towel. The amount of detergent cleaner used was
measured for each run (although this depends largely on the press operator's general practice), but it
was not possible to measure the amount of solvent cleaner previously used. Therefore, it was
assumed that the same amount of solvent cleaner would have been used as was consumed using the
detergent cleaner.
TABLE 3. COMPOSITION OF INKS TESTED AS REPORTED BY THE MANUFACTURERS
Type of Ink
Component
Percent by weight
Alcohol-based
Water-based
Methyl alcohol
Isopropyl alcohol
n-propyl alcohol
Ethyl alcohol
Ethyl acetate
VM&P naphtha
Resins
Pigment
Total Volatiles
Isopropyl alcohol
Ammonia
Dimethylethanolamine
Acrylic Resin
Azo pigment
Water
Total Volatiles
04.7
10.6
06.5
21.4
04.2
06.6
'Unknown
Unknown
54.5*
05.0
01.0
01.0
20.0
08.0
65.0
56.5*
* Both ink types contain plastic-based resins which react and bind with some of the other materials
present on drying, including some of the volatile materials. Hence, one cannot simply add the volatile
percentages to obtain total volatiles.
12
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TABLE 4. COMPOSITION OF CLEANERS TESTED AS REPORTED BY THE MANUFACTURERS
Type of cleaner Component Percent by weight
Organic solvent cleaner Toluene 54.5
Acetone 20.0
Isopropyl alcohol 20.0
Diacetone alcohol 05.5
Total volatiles 99. -f
Detergent cleaner Total volatiles 97.8
DEGREE-OF-HAZARD
Toxicity reduction evaluations on the ink and cleaner gaseous and liquid wastes were accomplished
with the Degree-of-Hazard scheme (10). This is a method developed and used by the Hazardous Waste
Research and Information Center and is not an EPA method or requirement. The Degree-of-Hazard is
calculated utilizing the equivalent toxic concentration, C*,, as follows (10):
C,, = YxSUM[C1/(B,xT,)] (5)
where SUM = sum of the results of the calculation in parentheses for each component of the .
waste stream.
C, = concentration of component i as a percent of the waste by weight
T, = measure of the toxicity of component i
Y is a constant equal to 300. It is used to allow entry of percent values for C, and to adjust the
results so that a reference material, 100% copper sulfate, with an oral toxicity of 300 mg/kg, achieves
an equivalent toxicity of 100.
B, is a conversion factor used to convert toxicities, T,, to equivalent oral toxicities. B, is determined
from Table 5. For carcinogens and mutagens, an oral rate TD60 is used when available. Otherwise,
carcinogens are assigned a T, of 0.1 mg/kg; and mutagens are assigned a T, of 0.6 mg/kg. Toxicities
are converted to equivalent oral toxicities as specified in Table 5. The equivalent toxicity given in
Table 5 has the same toxicological response as referenced in the RCRA listing criteria (10).
Toxicity values are ranked by type according to the following priorities, with the preferred types
listed first: oral rat, inhalation rat; dermal rat; or, aquatic toxicity and other mammalian toxicity values.
If there is more than one value for the toxicity from the preferred available source, the lowest (most
toxic) toxicity value is used. If a carcinogen is assigned a value for T, in the absence of a TD60, B, is
assigned a value of 1.00.
13
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The overall toxic amount, M, of each waste stream is calculated as follows:
M = Z x C., (6)
where Z — maximum size of waste stream produced, kg/month.
TABLE 5. TOXICITY CONVERSION FACTORS
Conversion factors for the
Toxicity measure
Oral - L.DBO
Caroinogen/mutagen - LD60
Aquatic - 48 or 96 hr - LCg,,
Inhalation - LCBO
Dermal - LD60
equivalent oral toxicities B,
Units
mg/kg
mg/kg
ppm
mg/l
mg/kg
B,
01.00
01.00
05.00
25.00
00.25
The result of these calculations will be an estimate of the relative toxic amount, M, of the gaseous
and liquid wastes produced for each ink and cleaner type evaluated. This toxic amount takes into
account the toxicity and amount of each component of the inks and cleaners. The toxic amount, M,
can range from 0 to greater than 10,000. This toxic amount can ben considered a relative toxicity of
each waste stream. The relative toxicities can then be compared for the air and liquid wastes
produced while printing with the two types of inks and cleaners.
ECONOMICS
The economic analysis of these changes is based on the factors shown in Table 6. Monetary
values are based on annual costs, the only valid approach since no capital investment was required;
hence, such terms as annual rate of return and payback are not applicable. The factors listed in Table
6 were selected after a tour of the plant and discussions with the plant manager. Certain qualitative
costs such as training of personnel, minor press modifications, cleanup time, compliance, and legal fees
are not included since it is hard to associate a monetary value with these items.
14
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TABLE 6. SUMMARY OF COST COMPARISON FACTORS EVALUATED
Material
Cost comparison factors
Inks
Cleaners
Overall
Raw materials
Waste disposal and handling
Raw materials
Waste disposal and handling
Insurance liability
Inventory control
Wiping materials
15
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SECTION 4
RESULTS
ON-SITE TESTING
Two single color label runs were evaluated at separate times on the same printing press. Two
different press operators produced different sizes and colors of labels during the runs. A brief
description of the label printing in this project are as follows:
1. green labels, approximately 3.25 x 13 inches, printed with green ink (yellow premixed with
blue) on non-glossy white stock for a total run of approximately 55,000 labels; and
2. purple labels, approximately 0.75 x 1.75 inches, printed with purple ink on glossy white stock
for a total run of approximately 250,000 labels.
In each case the total weight of materials added, equation 1, and the weight of materials remaining
at the end of the run was measured. The difference was the weight of material that was assumed to
be either evaporated to the shop air, dried on the labels, or wasted.
During the printing of the green labels, an ink pump was used to increase the size of the ink
reseivoir. Ink was continually recirculated between the ink pump and the ink pan. The weight of the
ink pump and ink contained in it was determined at the beginning before any labels were printed, B in
equation 1. During the course of that run water was added to the ink to adjust the color and viscosity
on nine occasions totaling 847.2 grams, C in equation 1. One spill, F in equation 1, occurred during
this run. The ink pan and gaskets adjacent to the roller were weighed before arid after the run to
measure the amount of ink retained on them after they were scraped, E in equation 1. During the
printing of the purple labels nothing was added, and there was no loss due to spillage.
The total weight of ink used during the printing of these two labels is shown in Table 7. For the
two water-based inks the total amount used was calculated according to equation 1. To estimate the
amount of ink evaporated, the percent loss as determined by laboratory evaporation was used
according to equation 2. The laboratory evaporation results are shown in Table 8. The amount of
solids retained on the labels was calculated from the percent solids ascertained in the laboratory as
applied in equation 3.
To estimate emissions that would have resulted from using alcohol-based inks, it was assumed that
the same amount of solids would have been used for printing the labels as was used for printing with
the water-based inks. Then the total amount of ink that would have been used and the weight
evaporated was calculated by using the percent loss factor determined in the laboratory. Since a lower
percentage of alcohol-based ink was lost to evaporation, more solids per gram of inks would be applied
to the labels than with the water-based ink. Thus, less total alcohol-ink would be used and less total
weight of components would be lost via evaporation. According to the operators at MPI Label
Systems, about the same total amount of ink is required for a job using either type of ink. Therefore,
16
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this analysis of emissions is conservative for the alcohol-based ink. It should be noted that laboratory
evaporation loss results presented in Table 7 agree favorably with the total volatiles data given in the
material safety data sheets, as shown in Table 3.
TABLE?. INK USED AND ESTIMATED EMISSIONS •
Determinations Green labels Purple labels
Water-based Alcohol-based Water-based Alcohol-based
Total ink used, grams
Ink solids retained on labels,
1459
609.8
1175
609.8
399.2
152.1
293.1
152.1
grams
Weight evaporated 849.1 565.2 247.1 141.0
TABLE 8. WEIGHT LOSS DATA FROM LABORATORY EVAPORATION AT 70°C
Material Initial weight
grams
Black water-based ink
Green water-based
ink
Purple water-based
ink
Black alcohol-based
ink
Detergent cleaner
09.82
12.7
14.0
10.7
13.4
12.1
10.4
14.0
12.3
11.8
16.2
18.1
10.5
13.6
13.6
Dry weight
grams
04.24
05.58
06.08
04.47
05.61
05.04
03.98
05.31
04.68
06.21
08.33
09.44
0.236
0.301
0.297
Weight loss
grams
05.58
07.10
07.94
06.20
07.75
07.07
06.41
08.70
07.60
05.59
07.88
08.67
02.25
02.21
02.19
Percent Loss Standard deviation
56.8
56.0
56.6
58.1
58.0
58.4
61.7
62.1
61.9 ;
47.4
48.6
47.9 s
97.8
97.8
97.8
0.42
0.21
0.20
0.60
0.03
The next step is to estimate the weight of air and water emissions of each specific component of
the inks studied. These estimates are presented in Tables 9-12, and were made using the percent
composition data from Table 3. For the water-based inks it was assumed that:all of the alcohol,
ammonia and amine evaporated and that the remainder of the loss was water.
17
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Concentrations of each volatilized constituent in the plant air were calculated based on the volume
of air in the shop area and the air exchange rate. These concentrations are levels expected during
continual operation of the press assuming all six print stations are being used to apply ink. Also it is
assumed that exposure to emissions from the cleaners was negligible and that they were entirely
discharged to the sewer. Under typical plant conditions and exposures to employees, peak
concentrations may exceed the levels presented.
TABLE 9. ESTIMATED AIR AND WATER EMISSIONS AT MP| LABEL SYSTEMS FOR TEST RUN
WITH GREEN LABELS AND WATER-BASED INK AND CLEANER
Components Amount of air Concentration % of total air Amount in Concentration Total %
of ink and emissions, in the air, emissions wastewater, in wastewater, in
cleaner grams ug/l grams ug/l wastewater
Isopropyl 72.9 06.0 8.0 1.2
alcohol
317 1.7
Ammonia 14.6
Dimethyl 14.6
ethanolamine
Water 747
Acrylic resin
Azo pigment
Water in
cleaner
Total 849.1
01.2
01.2
62
2.0
2.0
88
100
0.2
0.2
16
4.9
2.0
44
68.4
52.8
52.8
4230
1290
528
11700
0.30
0.30
23
7.1
2.9
64
100
Air emissions for printing with both types of inks were assumed to be entirely from the inks. The
fate of the cleaner components was assumed to be in the wastewater. For the two scenarios with
green labels, about 50% more air emissions resulted from the water-based inks. However, most of
these emissions, 88%, were the water component. By contrast, about 80% of the emissions from the
alcohol-based inks and cleaners were calculated to be various alcohols. Much lower concentrations
of the non-water constituents were estimated to be present than with the alcohol-based green ink.
A pattern similar to the air emissions was found with the purple labels. Of some concern with the
water-based inks are the ammonia and dimethyl ethanolamine components that are released. With the
alcohol-based inks four alcohols plus ethyl acetate and VM&P naphtha are released to the shop air.
Overall, more grams of inks and cleaner components were estimated to be released to the shop air
than were disposed of in the wastewater. This 5s because about 50% of the inks used is evaporated
and almost all of the liquid ink remaining in the reservoir at the end of the press run is returned to its
original container for reuse.
18
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TABLE 10. ESTIMATED AIR AND WATER EMISSIONS AT MPI LABEL SYSTEMS FOR TEST RUN
WITH GREEN LABELS AND ALCOHOL-BASED INK AND CLEANER
Components Amount of air Concentration % of total air Amount in
of ink and emissions, in the air, emissions wastewater,
cleaner grams ug/l grams
Concentration Total %
in wastewater, in
ug/l wastewater
Methyl alcohol
Isopropyl
alcohol
n-propyl
alcohol
49.2
111
68.0
4.1
9.2
5.6
09
20
12
1.1
2.6
1.6
290.6
686.9
422.7
1.6
3.8
2.3
Ethyl alcohol 224
Ethyl acetate 44.0
VM&P
naphtha
Resins
Pigment
Toluene
Acetone
Isopropyl
alcohol
Diacetone
alcohol
Total
69.1
18
3.6
5.7
40
08
12
565.3
100
5.3
1.0
1.6
5.7
5.7
24
8.9
8.9
2.4
68.9
1400
264.2
422.7
1510
1510
6370
2350
2350
634.1
7.7
1.5
2.3
8.3
8.3
35
13
13
3.5
100
Liquid wastes were generated only during cleanup at the end of each press run. These wastes
were minimal and consisted of ink left in the pan and on the rollers, gaskets and plates at the end of
the run after scraping, plus detergent cleaner. For the green run, 116.6 grams of ink remained in the
pan. A total of 44.3 grams (approximately 44 ml) of cleaner was used. All of this was disposed of
as wastewater for a total of 160.9 grams. During the cleanup of the purple labels only 56.4 grams
of liquid waste was produced. All of this excess ink was returned to the ink container for use on
subsequent runs. There was a more experienced operator for this run which resulted in less cleanup
being required and less wastage. No liquid wastes were generated except for a negligible amount on
a few cleanup rags. During these two runs most of the ink retained on the fabric rags resulted from
a spill that occurred during printing of the green labels. A total of 24.6 grams of inks was cleaned up
as a result. These rags were sent to an industrial laundry for cleaning and reuse. Thus, this spilled
ink also resulted in a liquid waste.
19
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TABLE 11. ESTIMATED AIR AND WATER EMISSIONS AT MPI LABEL SYSTEMS FOR TEST RUN
WITH PURPLE LABELS AND WATER-BASED INK AND CLEANER
Components
of ink. and
cleaner
Isopropyl
alcohol
Ammonia
Dimethyl
ethanolamine
Water
Acrylic resin
Azo pigment
Water in
cleaner
Total
Amount of air
emissions,
grams
20
04.0
04.0
219
-
.
-
248
Concentration % of total air
in the air, emissions
ug/l
05.3 8.0
01.1 2.0
01.1 2.0
58 88
-
-
-
100
Amount in
wastewater,
grams
0.6
0.1
0.1
7.9
2.4
1.0
44
56.1
Concentration Total %
in wastewater, in
ug/l wastewater
158
26.6
26.6
2090
634
264
1 1 700
- •
1.1
0.20
0.20
14
4.3
1.8
79
100
20
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TABLE 12. ESTIMATED AIR AND WATER EMISSIONS AT MPI LABEL SYSTEMS FOR TEST RUN
WITH PURPLE LABELS AND ALCOHOL-BASED INK AND CLEANER
Components Amount of air Concentration % of total air Amount in Concentration Total %
of ink and emissions, in the air, emissions wastewater, in wastewater, in
cleaner grams ug/l grams ug/l wastewater
Methyl alcohol 12.3 3.3
Isopropyl 27.7 7.3
alcohol
n-propyl 17.0 4.5
alcohol
Ethyl alcohol 55.9 15
Ethyl acetate 1 1 .0 2.9
VM&P 17.2 4.6
naphtha
Resins
Pigment
Toluene
Acetone
Isopropyl
alcohol
Diacetone
alcohol
Total 141
8.7 0.6
20 1.3
12 0.8
40 2.6
7.8 0.5
12 0.8
2.8
2.8
24
8.9
8.9
2.4
100 56.4
158.6
343.5
211.4
686.9
132.1
211.4
713.3
713.3
6370
2350
2350
634.1
-
1.1
2.3
1.4
4.6
0.9
1.4
4.9
4.9
43
16
16
4.3
100
DEGREE-OF-HAZARD ;
The Degree-of-Hazard analysis was conducted on the components generated in the liquid wastes
and the air emissions from the alcohol-based inks and cleaners versus the water-based inks and
cleaners. For the liquid wastes the toxicity values were based on oral toxicity. For the air emissions
the toxicity values were based on inhalation toxicity when such data were available. This
enhancement of the program demonstrates the flexibility for the degree of hazard system to
accommodate the physical form of the waste stream or the exposure route.
The equivalent toxic concentration, C., of equation 5, for the liquid wastes and air emissions for
the green and purple ink runs were calculated. The results of these calculations for liquid wastes and
air emissions for the alcohol-based ink and cleaner are presented in Tables 13-16. Tables 13 and 14
21
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present the data on liquid wastes for the green and purple alcohol-based inks and cleaners. The
equivalent toxic concentration for the green ink liquid alcohol waste was a value of 3.084 compared
to the value for the purple ink liquid alcohol waste which was 3.323. The calculated values for the
water-based liquid wastes, as shown in Tables 17 and 18, were about one tenth of the level for the
alcohol-based liquid wastes.
TABLE 13. DEGREE-OF-HAZARD ANALYSIS FOR MPI LABEL SYSTEMS GREEN ALCOHOL-BASED
INK AND CLEANER, LIQUID WASTE
Component name
Toluene
n-propyl alcohol
VM&P naphtha
Diacetone alcohol
Isopropanol
Acetone
Ethyl acetate
Ethariol
Methanol
Acrylic resin
Azo pigments
Total
Percent concentration
35
2.3
2.3
3.5
17
13
1.5
7.7
1.6
8.3
8.3
Component equivalent
toxic concentration
1 2.100
0.369
0.352
0.263
Innocuous
Innocuous
Innocuous
Innocuous
Innocuous
Innocuous
Unknown
3.084
22
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TABLE 14. DEGREE-OF-HAZARD ANALYSIS FOR MPI LABEL SYSTEMS PURPLE ALCOHOL-BASED
INK AND CLEANER, LIQUID WASTE I
Component name
Toluene
n-propyl alcohol
VM&P naphtha
Diacetone alcohol
Isopropanol
Acetone
Ethyl acetate
Ethanol
Methanol
Acrylic resin
Azo pigments
Total
Percent concentration
43
1.4
1.4
4.3
18
16
0.09
4.6
1.1
4.9
4.9
Component equivalent
toxic concentration
2.562
0.225
0.214
0.323
Innocuous
Innocuous
Innocuous
Innocuous
Innocuous
Innocuous
| Unknown
3.323
TAE5LE 15. DEGREE-OF-HAZARD ANALYSIS FOR MPI LABEL SYSTEMS
INK AND CLEANER, AIR EMISSIONS
GREEN ALCOHOL-BASED
Component name
n-propyl alcohol
VM&P naphtha
Ethyl acetate
Ethanol
Isopropanol
Methanol
Total
Percent concentration
12
12
08
40
20
09
Component equivalent
toxic concentration
1 .925
1.837
0.060
0.024
0.015
0.002
3.863
23
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TABLE 16. DEGREE-OF-HAZARD ANALYSIS FOR MPI LABEL SYSTEMS PURPLE ALCOHOL-BASED
INK AND CLEANER, AIR EMISSIONS
Component name
n-propyl alcohol
VMStP naphtha
Ethyl acetate
Ethanol
Isopropanol
Methanol
Total
Percent concentration
12.0
12.2
07.8
39.6
19.6
08.7
Component equivalent
toxic concentration
1 .925
1 .867
0.058
0.024
0.015
0.002
3.891
TABLE 17. DEGREE-OF-HAZARD
INK
ANALYSIS FOR MPI LABEL SYSTEMS
AND CLEANER, LIQUID WASTE
GREEN WATER-BASED
Component name
Ammonia
Dimethylethanolamine
Water
Isopropanol
Acrylic resin
Azo pigments
Total
Percent concentration
0.30
0.30
87.5
1.70
7.10
2.90
Component equivalent
toxic .concentration
0.257
0.450
Innocuous
Innocuous
Innocuous
Unknown
0.302
24
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TABLE 18. DEGREE-OF-HAZARD ANALYSIS FOR MPI LABEL SYSTEMS PURPLE WATER-BASED
INK AND CLEANER, LIQUID WASTE
Component name
Ammonia
Dimethylethanolamine
Water
Isopropanol
Acrylic resin
Azo pigments
Total
Percent concentration
0.20
0.20
92.5
1.10
4.30
1.80
Component equivalent
toxic concentration
0.171
0.030
Innocuous
Innocuous
Innocuous
Unknown
0.201'
The equivalent toxic concentration for the air emissions for the green and purple alcohol-based inks
and cleaners were 3.863 and 3.891, respectively. The equivalent toxic concentration for the air
emissions for the green and purple water-based inks and water based cleaners were both 0.318 and
shown in Tables 19 and 20.
TABLE 19. DEGREE-OF-HAZARD ANALYSIS FOR MPI LABEL SYSTEMS GREEN WATER-BASED
INK AND CLEANER, AIR EMISSIONS
Component name
Ammonia
Dimethylethanolamine
Water
Isopropanol
Total
. Percent concentration
2.0
2.0
88
8.0
Component equivalent
toxic concentration
0.012
0.300
Innocuous
0.006
! 0.318
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TABLE 21. SUMMARY OF EVALUATION OF ANNUAL COSTS AND SAVINGS
Parameter
Savings
Water-based inks
Printing speed
Raw Materials
Waste disposal and handling
Aqueous cleaners
Disposal
Raw materials
Overall Savings
Insurance liability
Inventory
Wiping materials
Total Annually
Approximately 10% faster
None
Minimum annual savings = $10,000
Minimum annual savings = $5,000
None
Approximately $500/yr
None
Annually at least $1,000
At least $16,500
A significant offsetting factor was MPi Label Systems' decision to install a unit to decolor its waste
inks prior to discharge to the sewer. The capital cost of this unit was approximately $ 18,000 and the
colored absorbent is acceptable at the local municipal landfill. Since this treatment unit was not
required by the local publicly owned treatment works (POTW) as part of the change to water-based
inks, its purchase and operating costs are not included in this analysis. There are areas which require
ink waste to be treated before discharge to the sewer. For those areas where pretreatment is a
requirement, the savings in the first year should be offset.
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SECTION 5
QUALITY ASSURANCE
The quality assurance/quality control (QA/QC) project plan submitted for this project was written
to validate the quantitative comparison of the volume and toxicity of any waste generated during
printing and released as gaseous, liquid and solid wastes, before and after switching to water-based
inks and a detergent cleaner, and the economic impact resulting from modification of a traditional
printing technology.
The on-site mass measurements were taken on an electronic balance (capacity 12 kgs +_ 0.01 g)
which was transported to the printing site. After transportation the balance was calibrated using its
internal calibration function, and checking the calibration using Class S weights.
The laboratory samples were analyzed in triplicate with results presented in Section 4. These
results show that none of the individual analyses were outliers. The standard deviation for the
triplicate analyses ranged from 0.03 - 0.60.
The data collected initially for this project had to be dismissed because MPI Label Systems set up
for the print run the night before. This did not allow the initial mass measurements of the inks to be
taken. Great efforts were made, during the second attempt, to ensure that the quality data objectives
for this project were not compromised, the original data quality objectives stated in the QA/QC project
plan were met on this project.
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REFERENCES
1. 1989 Technology Forecast. Graphic Arts Technical Foundation, Pittsburgh, PA, 1989.
2. Third Flexo Plant Survey. Flexographic Technical Association, Appleton, Wl, 1983.
3. Satas, D. Handbook of Pressure Sensitive Adhesive Technoloov. Van Nostrand-Reinhold, New
York.
4. Ouzinskas, Donald R. The Systems Approach to Pressroom Ventilation in Solvent Recovery. 36th
Annual Meeting, Gravure Research Institute, W.F. Hall Printing Co., November 1983.
5. Guides to Pollution Prevention - The Commercial Printing Industry. EPA/672/7-90/008, U.S.
Environmental Protection Agency, Cincinnati, OH, August 1990.
6. James, Christopher A. RACT Compliance: VOC Emissions Reductions From Rhode Island Printing
and Surface Coaino Sources. Rhode Island Division of Air and Hazardous Materials, Providence,
Rl, 1987.
7. Rosen, D.R., and Wool, M.R. Microprocessor Control of Rotogravure Airflows. Acurex
Corporation, Mountain View, CA, August 1986. ;
8. Waste Audit Study - Commercial Printing Industry. California Department of Health Services,
Alternative Technology Section, Sacramento, CA, May 1986.
9. Makrauer, George A. Innovations in Flexographic Printing: Reducing VOCs With Water-based Inks
When Printing on High-slip Polyethylene Rims. AMKO Plastics, Inc., Cincinnati, OH, 1987.
10. Plewa, M., Dowd, P., Ades, D., and E. Wagner. Assigning a Degree of Hazardous Ranking to
Illinois Waste Streams. HWRIC RR 013, Hazardous Waste Research and Information Center,
Champaign, IL, November 1986.
REFERENCES NOT-CITED
Material Safety Data Sheet for Alcohol-based Ink. BASF Corp;, Clifton, NJ, December 1988.
Material Safety Data Sheet for Detergent Cleaner. Water Ink Technologies, Inc.; Iron Station, NC,
November 1990.
Material Safety Data Sheet for Water-based Ink. Water Ink Technologies, Inc., Iron Station, NC,
May 1988. ',
Registry of Toxic Effects of Chemical Substances. U.S. Department of Health and Human
Services, Vol. I, 1985-1986 Edition.
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