EXECUTIVE SUMMARY
Executive Summary
Flexographic Ink Options: A Cleaner Technologies Substitutes Assessment (the Flexographic
Inks CTSA) presents the results of a technical study of the comparative environmental
impacts, health risks, performance, and cost of the three primary flexographic printing ink
systems: solvent-based inks, water-based inks, and ultra-violet (UV)-cured inks. The study
was initiated through the Flexography Partnership of the Design for the Environment (DfE)
Program at the U.S. Environmental Protection Agency (EPA).* The broad goal of the CTSA
was to develop as complete and systematic a picture as possible of competing ink
technologies, thereby helping industry incorporate environmental and health information into
their ink decisions. It is hoped that the CTSA will serve as a resource to
?identify and inform industry about comparative chemical risks in inks, including
unregulated ones that present opportunities for proactive, voluntary risk management,
?facilitate the use and formulation of cleaner inks, and
?encourage adoption of workplace practices that minimize health and environmental
risks from exposure to chemicals of concern.
The study examined ink systems that are used on wide-web film substrates, a combination that
presented special technical and environmental challenges for printers. Notably, at the time
the study was initiated, use of UV-cured inks on wide-web film substrates was still in
a developmental stage and was just beginning to emerge commercially. One of the
benefits of the CTSA approach is its ability to provide unbiased insights into the
environmental and health impacts and competitiveness of emerging technologies.
Interestingly, the CTSA found that each of the ink systems studied had different advantages,
as well as health and environmental concerns. Considerable variation was noted even among
different colors within a single ink product line. Thus, selecting the best formulations is just
as important for a printer as selecting an ink system. The CTSA results can help printers and
formulators familiarize themselves with the toxicities of chemicals they use on a daily basis,
be more aware of their risk concerns, and identify cleaner ink systems, formulations, and
chemicals.
The primary audiences for the Flexographic Inks CTSA are flexographic printers, ink
manufacturers, environmental health and safety personnel, community groups, and other
technically informed decision makers.
*
EPA's Design for the Environment Program is located within the Economics, Exposure and Technology
Division, in the Office of Pollution Prevention and Toxics.
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EXECUTIVE SUMMARY
The Flexography Partnership is a voluntary, cooperative effort among EPA, industry,
academia, public interest groups, and other stakeholders. Project partners participated in all
stages of planning and implementing this CTSA. They helped define its scope and direction,
provided technical information, reviewed data and text, and donated time, materials, and
printing facilities for performance demonstrations. Critical information about ink
formulations used in the analyses was provided by ink manufacturers.
In addition to the Flexographic Inks CTSA, the Flexography Partnership has developed a
summary report, a pollution prevention video, and a number of other materials for printers.
These may be obtained from the DfE website (www.epa.gov/dfe) or by contacting EPA's
National Service Center for Environmental Publications (telephone 800-490-9198 or 513-489-
8190; fax 513-489-8695; Internet address www.epa.gov/ncepihom/ordering.htm; e-mail
ncepimal@one.net).
This Executive Summary first provides a brief background of the flexographic industry, the
DfE Program, and the Flexographic Inks CTSA. It then presents key results on the main
research areas: environmental impacts and health concerns, performance, and costs. It ends
with some steps that flexographic professionals could take to minimize impacts on the
environment and worker health.
BACKGROUND OF THE DFE FLEXOGRAPHY PROJECT
The Flexographic Printing Industry
Flexography is a process used primarily for printing on paper, corrugated paperboard, and
flexible plastic materials. Especially well suited to printing on flexible and non-uniform
surfaces (such as plastic films and corrugated board), flexography is used to print a wide
range of products we all use, such as snack food and frozen food bags, labels for medicines
and personal care products, newspapers, drink bottles, and cereal containers (Figure ES.1).
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EXECUTIVE SUMMARY
Figure ES.1 Primary Types of Packaging Manufactured in the United States, 2000
(by % of sales dollars)
other (including glass corrugated and
and cans) preprinted containers
32% 27%
labels and tags flexible film packaging
9% 19%
folding cartons
13%
Flexography is a highly visible, growing, national industry that is dominated by small
businesses. Combined, these businesses have the potential to make a major environmental
impact, especially on air quality, resource use (e.g., inks and substrates), and solid and
hazardous waste.
? U.S. flexographic printing firms had annual sales of approximately $50 billion in
1999.1
The sector employs about 30,000 people.2
?br>
? More than 80% of all flexography firms have fewer than 50 employees.
It has an annual growth rate of about 6%.3
?br>
? Roughly 60% of flexographic businesses are concentrated in ten states: California,
Florida, Illinois, Missouri, New Jersey, New York, North Carolina, Ohio, Texas, and
Wisconsin.4
Flexographic printing consumed more than 513 million pounds of ink in 2000.5
?br>
EPA's Design for the Environment Program
The Design for the Environment (DfE) Program is a voluntary
partnership program that works directly with industries, usually
through industry leaders and trade or technical associations, to
integrate health and environmental considerations into their
business decisions. The DfE approach compares the human
health and environmental risks, performance, and costs
associated with existing and alternative technologies or
processes. DfE helps businesses design or redesign products,
processes, and management systems that are cleaner, more cost-
effective, and safer for workers and the public.
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EXECUTIVE SUMMARY
DfE partnerships may take several approaches to designing for the environment: technology
assessments, formulator approaches, best practices approaches, greening the supply chain,
integrated environmental management systems, and life-cycle assessments. DfE has
established partnerships in commercial printing (flexography, lithography, and screen
printing), garment and textile care, computer monitors, printing wiring boards (used for
computers and other electronics), industrial and institutional cleaning formulations,
automotive refinishing, adhesives used in foam furniture and sleep products, and automotive
suppliers.
Background and General Methodology of the Flexographic Inks CTSA
In the mid-1990s, DfE identified flexography as an important industry sector that
could benefit from a DfE assessment:
? Historically, most flexographic inks had been solvent-based, had high levels of
volatile organic compounds (VOCs), and contained many chemicals, some of which
were quite toxic. Although the printing industry has addressed a number of
environmental and health concerns of inks through reformulation of inks, add-on
pollution control devices, and other improvements to operations and materials, these
had not resolved all concerns about human health and ecological risks.
? Inks are a major use and cost category for printers.
? As small businesses, individual flexography firms might not have the resources or
expertise to research the environmental implications of competing technologies.
? The industry had been growing rapidly for several years, which increases its impacts.
The Flexography Partnership decided to perform a cleaner technologies substitutes
assessment or CTSA for flexographic inks. This methodology allowed the Partners
to evaluate traditional and alternative technologies for the potential risks they pose to
human health and the environment, as well as for performance and cost. The CTSA
methodology is described in the DfE document, Cleaner Technologies Substitutes
Assessment: A Methodology and Resources Guide.** Figure ES.2 graphically displays
the methodology used for this CTSA.
**
See the beginning of this volume (page ii) for ordering information.
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EXECUTIVE SUMMARY
Figure ES.2 Flexographic Inks CTSA Methodology
ENVIRONMENTAL IMPACTS AND HEALTH CONCERNS
This section describes the risk assessment methodology that was used to obtain and evaluate
the health and environmental findings for flexographic inks. Findings related to workers and
the general population are discussed first. Environmental findings follow, including (1)
ambient air releases, (2) aquatic toxicity, and (3) resource use and energy conservation.
Over the past decade, ink manufacturers have made environmental improvements by
developing inks with lower VOC content. The Flexography Partnership wanted to obtain an
even deeper understanding of environmental and health implications of ink chemicals, to help
the industry innovate and select cleaner inks, and to ensure that new formulations were not
shifting risks from one medium to another (e.g., from ambient air quality to worker health).
The study examined 45 ink formulations, which contained approximately 100 chemical
substances (Table ES.1). Ink suppliers voluntarily provided the inks, along with complete
information about the chemical compositions of their formulations. To compare the
environmental and health implications of the three ink systems, the study examined the
toxicity, estimated releases and exposures, and risk concerns for the chemicals. To protect
manufacturers' confidentiality, the formulation information they provided was treated as
confidential business information.
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EXECUTIVE SUMMARY
Table ES.1 Categorization of Ink Chemicals
CAS
Category Chemicals in category
number
Acrylated polyols Dipropylene glycol diacrylate 57472-68-1
1,6-Hexanediol diacrylate 13048-33-4
Hydroxypropyl acrylate 25584-83-2
Trimethylolpropane triacrylate 15625-89-5
Acrylated epoxy polymerc NAa
Acrylated
Acrylated oligoamine polymerc
polymers NA
Acrylated polyester polymer (#'s 1 and 2)c NA
Glycerol propoxylate triacrylate 52408-84-1
Trimethylolpropane ethoxylate triacrylate 28961-43-5
Trimethylolpropane propoxylate triacrylate 53879-54-2
Acrylic acid Acrylic acid-butyl acrylate-methyl methacrylate- 27306-39-4
polymers styrene polymer
Acrylic acid polymer, acidic (#'s 1 and 2)c NA
Acrylic acid polymer, insolublec NA
Butyl acrylate-methacrylic acid-methyl 25035-69-2
methacrylate polymer
Styrene acrylic acid polymer (#'s 1 and 2)c NA
Styrene acrylic acid resinc NA
Alcohols Ethanol 64-17-5
Isobutanol 78-83-1
Isopropanol 67-63-0
Propanol 71-23-8
Tetramethyldecyndiol 126-86-3
Alkyl acetates Butyl acetate 123-86-4
Ethyl acetate 141-78-6
Propyl acetate 109-60-4
Amides or Amides, tallow, hydrogenated 61790-31-6
nitrogenous Ammonia 7664-41-7
compounds Ammonium hydroxide 1336-21-6
Erucamide 112-84-5
Ethanolamine 141-43-5
Hydroxylamine derivative NA
Urea 57-13-6
Aromatic esters Dicyclohexyl phthalate 84-61-7
Ethyl 4-dimethylaminobenzoate 10287-53-5
119313-12-1
Aromatic ketones 2-Benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone
947-19-3
1-Hydroxycyclohexyl phenyl ketone
7473-98-5
2-Hydroxy-2-methylpropiophenone
5495-84-1
2-Isopropylthioxanthone
83846-86-0
4-Isopropylthioxanthone
71868-10-5
2-Methyl-4'-(methylthio)-2-morpholinopropiophenone
Thioxanthone derivativec NA
Ethylene glycol Alcohols, C11-15-secondary, ethoxylated 68131-40-8
ethers Butyl carbitol 112-34-5
Ethoxylated tetramethyldecyndiol 9014-85-1
Ethyl carbitol 111-90-0
Polyethylene glycol 25322-68-3
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EXECUTIVE SUMMARY
CAS
Category Chemicals in category
number
Hydrocarbons -- Distillates (petroleum), hydrotreated light 64742-47-8
high molecular Distillates (petroleum), solvent-refined light paraffinic 64741-89-5
weight Mineral oil 8012-95-1
Paraffin wax 8002-74-2
Hydrocarbons -- n-Heptane 142-82-5
low molecular Solvent naphtha (petroleum), light aliphatic 64742-89-8
weight Styrene 100-42-5
Inorganics Barium 7440-39-3
Kaolin 1332-58-7
Silica 7631-86-9
Olefin polymers Polyethylene 9002-88-4
Polytetrafluoroethylene 9002-84-0
Organic acids or Citric acid 77-92-9
salts Dioctyl sulfosuccinate, sodium salt 577-11-7
Methylenedisalicylic acid 27496-82-8
Organophos- Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide 75980-60-8
phorus 2-Ethylhexyl diphenyl phosphate 1241-94-7
compounds Phosphine oxide, bis(2,6-dimethoxybenzoyl) 145052-34-2
(2,4,4-trimethylpentyl)-
Organotitanium Isopropoxyethoxytitanium bis(acetylacetonate) 68586-02-7
compounds Titanium diisopropoxide bis(2,4-pentanedionate) 17927-72-9
Titanium isopropoxide 546-68-9
Pigments -- C.I. Pigment White 6 13463-67-7
inorganic C.I. Pigment White 7 1314-98-3
Pigments -- C.I. Pigment Blue 61 1324-76-1
organic C.I. Pigment Red 23 6471-49-4
C.I. Pigment Red 269 67990-05-0
C.I. Pigment Violet 23 6358-30-1
C.I. Pigment Yellow 14 5468-75-7
C.I. Pigment Yellow 74 6358-31-2
Pigments -- C.I. Basic Violet 1, molybdatephosphate 67989-22-4
organometallic C.I. Basic Violet 1, molybdate-tungstatephosphate 1325-82-2
C.I. Pigment Blue 15 147-14-8
C.I. Pigment Green 7 1328-53-6
C.I. Pigment Red 48, barium salt (1:1) 7585-41-3
C.I. Pigment Red 48, calcium salt (1:1) 7023-61-2
C.I. Pigment Red 52, calcium salt (1:1) 17852-99-2
C.I. Pigment Violet 27 12237-62-6
D&C Red No. 7 5281-04-9
9004-70-0
Polyol derivatives Nitrocellulose
Polyol derivative Ac --b
Propylene glycol Dipropylene glycol methyl ether 34590-94-8
ethers Propylene glycol methyl ether 107-98-2
Propylene glycol propyl ether 1569-01-3
ES-7
EXECUTIVE SUMMARY
CAS
Category Chemicals in category
number
Fatty acid, dimer-based polyamidec
Resins NA
Fatty acids, C18-unsatd., dimers, polymers with 67989-30-4
ethylenediamine, hexamethylenediamine, and propionic acid
Resin acids, hydrogenated, methyl esters 8050-15-5
Resin, acrylicc NA
Resin, miscellaneousc NA
Rosin, fumarated, polymer with diethylene glycol 68152-50-1
and pentaerythritol
Rosin, fumarated, polymer with pentaerythritol, NA
2-propenoic acid, ethenylbenzene, and (1-
methylethylenyl)benzenec
Rosin, polymerized 65997-05-9
Siloxanes Silanamine, 1,1,1-trimethyl-N-(trimethylsilyl)-, 68909-20-6
hydrolysis products with silica
Silicone oil 63148-62-9
Siloxanes and silicones, di-Me, 3-hydroxypropyl 70914-12-4
Me, ethers with polyethylene glycol acetate
a
No data or information available.
b
Actual chemical name is confidential business information.
c
Some structural information is given for these chemicals. For polymers, the submitter has supplied the number
average molecular weight and degree of functionality. The physical property data are estimated from this information.
The CTSA Risk Assessment Methodology
A risk assessment has several phases: hazard identification, dose-response assessment,
exposure assessment, and risk characterization. The CTSA risk assessment (Figure ES.3)
focused on two areas of interest regarding the chemicals:
?possible health concerns to industry workers and the general population, and
?environmental concerns, including ambient air releases and aquatic toxicity.
For flexographic workers, exposures were analyzed for prep room workers and press workers,
since both of these groups handle inks regularly in the course of their jobs. The assessment
included exposure to VOCs and hazardous air pollutants (HAPs) through fugitive releases,
which escape from the printing process into the ambient internal air and eventually exit the
facility through windows and doors. Workers therefore can be exposed to fugitive emissions
in the facility.
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EXECUTIVE SUMMARY
Figure ES.3 The Flexographic Inks CTSA Risk Assessment Process
Exposure was "modeled" -- that is, it was not based on actual measurements of releases. A
number of assumptions were made about a hypothetical "model facility" in developing the risk
assessment. Most of the assumptions reflect typical operating conditions, and some facilitated
identification of cleaner technologies or comparative analysis. Facilities with different
operating characteristics would have different findings. Some of the assumptions include the
following:
?30% of volatile compounds released to air would be uncaptured emissions, and 70%
would be stack emissions.
?Solvent-based ink systems would have a catalytic oxidizer with a 95% destruction
efficiency.
?Press and prep-room workers would work a 7.5 hour shift, 250 days/year.
?Press and prep room workers would have routine two-hand contact (no gloves) with
ink unless a substance was corrosive.
?Press speed would be 500 feet per minute.
In addition, the exposure estimates used for dermal contact were "bounding" estimates, which
provide an upper and lower limit of exposure. The inhalation exposure estimates are
considered "what-if" estimates because their probability of occurrence is not known.
The risk analysis used published studies of hazards and toxicity associated with each
chemical, where available. When published studies were not available, EPA's Structure
Activity Team (SAT) determined hazard levels based on analog data and/or structure activity
considerations, in which characteristics of the chemicals were estimated in part based on
similarities with chemicals that have been studied more thoroughly. Many chemicals in
flexographic inks have not been studied thoroughly for environmental effects or health
concerns. Chemicals in UV-cured inks, perhaps because they are newer, are much less likely
than solvent- and water-based chemicals to have undergone in-depth testing.
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EXECUTIVE SUMMARY
Concerns posed by any ink system will vary depending upon many factors, such as the
specific chemicals in the inks, how the inks are handled and used, the type of toxicity
(systemic or developmental), and the exposure route (inhalation or dermal).
How the CTSA Defined Risk Levels
Each chemical substance evaluated was designated as having a "clear," "potential," or "low"
concern for risk (Table ES.2). Clear concern for risk indicates that for the chemical in
question, under the assumed exposure conditions of the Flexographic inks CTSA research,
adverse effects were predicted to occur. Potential concern for risk indicates that for the
chemical in question, under the assumed exposure conditions, adverse effects may occur. Low
or negligible concern for risk indicates that for the chemical in question, under the assumed
exposure conditions, no adverse effects were expected.
Table ES.2 Criteria for Risk Levels
Level of Margin of Exposure b SAT Hazard
Concern for Hazard Quotient a
Rating C
NOAEL LOAEL
Risk
Clear > 10 1 to 10 1 to 100 moderate or high
Potential 1 to 10 > 10 to 100 > 100 to 1,000 low-moderate
Low or <1 > 100 > 1,000 low
negligible
a
Hazard Quotient (HQ) is the ratio of the average daily dose (ADD) to the Reference Dose (RfD) or
Reference Concentration (RfC), where RfD and RfC are defined as the lowest daily human exposure that
is likely to be without appreciable risk of non-cancer toxic effects during a lifetime. The more the HQ
exceeds 1, the greater the level of concern. HQ values below 1 imply that adverse effects are not likely
to occur.
B
NOAEL = No Observed Adverse Effect Level. LOAEL = Lowest Observed Adverse Effect Level. A
Margin of Exposure (MOE) is calculated when a RfD or RfC is not available. It is the ratio of the NOAEL
or LOAEL of a chemical to the estimated human dose or exposure level. The NOAEL is the level at
which no significant adverse effects are observed. The LOAEL is the lowest concentration at which
adverse effects are observed. The MOE indicates the magnitude by which the NOAEL or LOAEL
exceeds the estimated human dose or exposure level. High MOE values (e.g., greater than 100 for a
NOAEL-based MOE or greater than 1,000 for a LOAEL-based MOE) imply a low level of risk. As the
MOE decreases, the level of risk increases.
C
This column presents the level of risk concern if exposure is expected. If exposure is not expected, the
level of risk concern is assumed to be low or negligible. SAT-based systemic toxicity concerns were
ranked according to the following criteria: high concern -- evidence of adverse effects in humans, or
conclusive evidence of severe effects in animal studies; moderate concern -- suggestive evidence of
toxic effects in animals; or close structural, functional, and/or mechanistic analogy to chemicals with
known toxicity; low concern -- chemicals not meeting the above criteria.
Human Health Findings
The toxicity information was combined with estimated releases and exposures to develop a
risk characterization of individual chemical substances.Each chemical substance was analyzed
for systemic and developmental toxicity. Systemic toxicity means adverse effects on any organ
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EXECUTIVE SUMMARY
system following absorption and distribution of a chemical throughout the body.
Developmental toxicity refers to adverse effects on a developing organism that may result
from as little as a single exposure prior to conception, during prenatal development, or
postnatally up to the time of sexual maturation. The major manifestations of developmental
toxicity are death, structural abnormality, altered growth, or functional deficiency. Although
some inks in the CTSA also contained known or possible human carcinogens, there was not
enough quantitative information to analyze specific cancer risk concerns.
Worker Health Risks
The study assessed possible risks via both the inhalation and dermal (skin) pathways. Each
ink system contained chemicals that showed clear health risk concerns for workers who handle
inks in the prep room or pressroom, under the assumptions used for the study.
Of the roughly 100 chemicals studied, 24 were found to pose clear worker health risk
concerns (Tables ES.3 and ES.4).***
?Alcohols, amides and nitrogenous compounds, and acrylated polyols contained the most
chemicals found to pose clear worker risk concerns.
?For pressroom workers, exposure was highest with solvent-based inks because of the
higher air release rate.
?In the three solvent-based ink product lines studied, most of the chemicals presenting
a clear occupational risk concern were solvents. Pressroom workers can be exposed to
uncaptured (i.e., fugitive) emissions in the facility, while stack emissions from using
solvent-based inks are destroyed by oxidizers. The use of oxidizers thus only impacts
stack emissions and does not reduce occupational health hazards and risk concerns.
?In water-based formulations, amides or nitrogenous compounds often presented
systemic risk concerns.
?The use of press-side solvents and additives increased the occupational risk concern for
many of the solvent- and water-based ink formulations. In particular, alcohols and
propylene glycol ethers in solvent-based inks, and amides and nitrogenous compounds,
alcohols, and ethylene glycol ethers in water-based inks presented clear or potential
occupational risk concerns in certain formulations.
?For UV-cured inks, some acrylated polyols and amides or nitrogenous compounds
showed clear inhalation risk concerns for workers. It is important to understand,
however, that the CTSA studied uncured UV inks only, due to resource limitations.
The concerns associated with cured UV inks are not known, but anecdotal information
from industry suggests that curing may greatly reduce such concerns.
***
To protect manufacturers' proprietary information, when discussing formulations the risk results
group the specific chemicals into categories rather than presenting results for individual chemicals.
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EXECUTIVE SUMMARY
Table ES.3 Clear INHALATION Risk Concerns for Flexographic Workers
Ink System Chemical Categories with Chemicals of Systemic Developmental
Clear Risk Concern Risk Concern Risk Concern
Solvent-based Alcohols X X
Alkyl acetates X
Hydrocarbons (low molecular weight) X
Propylene glycol ethers X
Water-based Alcohols X
Amides or nitrogenous compounds X X
Ethylene glycol ethers X
UV-cured Acrylated polyols X X
Amides or nitrogenous compounds X X
Table ES.4 Clear DERMAL Risk Concerns for Flexographic Workers
Ink System Chemical Categories with Chemicals of Systemic Developmental
Clear Risk Concern Risk Concern Risk Concern
Solvent-based Alcohols X X
Alkyl acetates X
Inorganics X X
Organometallic pigments X
Organotitanium compounds X
Organic acids or salts X
Propylene glycol ethers X
Water-based Alcohols X X
Amides or nitrogenous compounds X X
Ethylene glycol ethers X
Organic pigments X
Organometallic pigments X
UV-cured Acrylated polyols X X
Acrylated polymers X X
Amides or nitrogenous compounds X X
Inorganic pigments X
Organometallic pigments X
Organophosphorus compounds X
Table ES.5 lists the potential effects on organ systems (e.g., cardiac, respiratory,
reproductive) from dermal and inhalation exposure to chemicals and chemical categories of
clear worker health risk concern. "Toxicological endpoints" are the potential effects on organ
systems that have been reported in the medical literature and other scientific reports in
association with use of a chemical. This does not mean, however, that any of these effects are
necessarily caused by that chemical. Only the chemicals listed for a specific category were
associated with clear worker risk concerns. Thus, for example, CI Pigment Red 23 was the
only organic pigment that showed clear worker health risk concerns. A number of the ink
chemical categories that were examined in the study (e.g., resins, olefin polymers, siloxanes)
did not show clear risk concerns and thus are not included in this table.
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EXECUTIVE SUMMARY
Table Toxicological Endpoints of CTSA Chemicals with
CLEAR Worker Health Risk Concerns
Chemical Chemical Potential Effects on Organ Systems (via oral and dermal
d
Category paths)
Acrylated Glycerol propoxylate tissue necrosis at application site, decreased body weight,
polymers triacrylate neurotoxic and respiratory effects
Acrylated Dipropylene glycol genotoxicity, neurotoxicity, oncogenicity, developmental and
diacrylate (SAT)a
polyols reproductive effects, dermal and respiratory sensitization, and
skin and eye irritation
1,6-Hexanediol diacrylate developmental effects
Hydroxypropyl acrylate respiratory effects
Trimethylolpropane decreased body weight, skin and neurotoxic effects, changes
in clinical chemistry, altered organ weights, respiratory effects
triacrylate
Alcohols Ethanol blood, liver, neurotoxic, and reproductive effects, decreased
cellularity of the spleen, thymus, and bone marrow; dev: fetal
malformations
Isobutanol blood and neurotoxic effects, changes in enzyme levels; dev:
cardiac septal defects
Isopropanol blood and skin effects, tissue necrosis at application site,
increased kidney and liver weight; liver, neurotoxic,
reproductive, respiratory, and spleen effects, changes in
enzyme levels and clinical and urine chemistry; dev: fetal
death, musculoskeletal abnormalities, fetotoxicity
Alkyl acetates Butyl acetate changes in serum chemistry, fluctuations in blood pressure;
dev: fetotoxicity, musculoskeletal abnormalities
Ethyl acetate blood, cardiovascular, gastrointestinal, kidney, liver,
neurotoxic, and respiratory effects, decreased spleen and liver
weight, increased adrenal, lung, and kidney weight
Amides or Ammonia corneal, liver, respiratory, and spleen effects
nitrogenous
Ammonium hydroxide eye effects, nasal irritation, respiratory effects
compounds
Ethanolamine respiratory irritation; kidney, liver, neurotoxic, and respiratory
effects
Hydroxylamine derivative genotoxicity, dermal sensitization, developmental toxicity
(SAT) a
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EXECUTIVE SUMMARY
Chemical Chemical Potential Effects on Organ Systems (via oral and dermal
d
Category paths)
Ethylene glycol Butyl carbitol blood and skin effect, liver effects
ethers
Alcohols, C11-C15- skin irritant; eye irritation and lung effects
secondary, ethoxylated
(SAT)a
Ethyl carbitol no data
Hydrocarbons n-Heptane auditory and neurotoxic effects, altered serum chemistry
-- low
molecular
weight
Inorganics Barium decreased body weight, reproductive and respiratory effects,
increased arterial blood pressure; dev: decreased survival and
weight gain, changes in hematology parameters
Organic acids Dioctyl sulfosuccinate, no data
or salts sodium salt
Organo- Phosphine oxide, bis(2,6- no data
phosphorous dimethoxybenzoyl) (2,4,4-
compounds trimethylpentyl)-
Organotitanium Isopropoxyethoxytitanium neurotoxicity, genotoxicity, oncotoxicity, and developmental/
bis(acetylacetonate) (SAT)a
compounds reproductive toxicity; skin, eye, mucous membrane irritant
Titanium diisopropoxide SAT: irritation of the eyes, skin, and mucous membranes.
bis(2,4-pentanedionate) Moderate concern based on release of hydrolysis products:
2,4 pentanedione, inorganic titanium, and isopropanol. 2,4
pentanedione: concern for neurotoxicity, mutagenicity,
oncogenicity, and developmental/reproductive toxicity.
Inorganic titanium: concern for mutagenicity and oncogenicity.
Isopropanol: concern for liver, neurotoxic, reproductive,
respiratory, and spleen effects; changes in enzyme levels and
clinical and urine chemistry; fetal death, musculoskeletal
abnormalities, fetotoxicity, blood and skin effects, tissue
necrosis at application site, increased kidney and liver weight
Titanium isopropoxide SAT: irritation of the eyes, skin, and mucous membranes.
Moderate concern based on release of the hydrolysis
products, inorganic titanium and isopropanol. Inorganic
titanium: concern for mutagenicity and oncogenicity.
Isopropanol: concern for liver, neurotoxic, reproductive,
respiratory, and spleen effects; changes in enzyme levels and
clinical and urine chemistry; fetal death, musculoskeletal
abnormalities, fetotoxicity, blood and skin effects, tissue
necrosis at application site, increased kidney and liver weight.
Pigments -- CI Pigment Red 23 no data
organic
Pigments -- D&C Red No. 7 no data
organometallic
ES-14
EXECUTIVE SUMMARY
Chemical Chemical Potential Effects on Organ Systems (via oral and dermal
d
Category paths)
Propylene Propylene glycol methyl increased mortality; blood, neurotoxic, and skin effects; altered
glycol ethers ether kidney weights; decreased growth, liver, neurotoxic,
reproductive, and respiratory effects, increased liver and
kidney weights; dev: delayed ossification of vertebrae,
musculoskeletal abnormalities
These chemical categories posed risk concerns under the specific conditions of this study; they might be associated
with different risks, or with no risk at all, under different conditions.
Dev = developmental effects. All endpoints not specifically indicated as developmental are systemic.
a
SAT: Structure Activity Team and acute data reports.
d
Developmental risks for SAT-evaluated chemicals were evaluated on a "concern/no concern" basis.
ES-15
EXECUTIVE SUMMARY
Many of the chemical substances that show hazard or risk concern are commonly used in
flexographic inks, although they are not necessarily found in every ink formulation. To protect
workers from such concerns, printing firms can take several steps:
?Review ink formulations against CTSA data, MSDS information, Table 8.13 of the
Flexographic Inks CTSA, and other sources to identify chemicals that may present
concerns under certain conditions of use.
?Establish effective policies that require workers to wear proper gloves and other
personal protective gear when working with inks. If workers wear appropriate
protections, the dermal concern is essentially zero.
?Ensure appropriate ventilation to minimize inhalation exposure.
?Adopt pollution prevention practices to minimize use and disposal of chemicals of
concern (e.g., management of chemical inventory).
General Population Risks
For the general population (people who live near a printing facility), the study assessed
possible inhalation risks. No chemical categories showed a clear risk concern to the general
population. However, alcohols in solvent- and water-based inks, and acrylated polyols in UV-
cured inks, included one or more chemicals that showed a potential risk concern for the
general population. Exposures and risk concerns for the general population due to emissions
from water-based and UV-cured inks were calculated to be significantly lower than those of
solvent-based inks. This is because solvent-based inks showed higher fugitive emissions (e.g.,
chemicals released from a long web run between presses), which outweighed the decrease in
stack emissions resulting from the use of oxidizers.
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EXECUTIVE SUMMARY
Environmental Findings
Ambient Air Releases
Releases to air result from the evaporation of chemicals during the flexographic printing
process. Releases to air are used to estimate inhalation exposure to particular chemicals for
workers and the general population. The CTSA examined two forms of air releases. Stack
emissions are collected from the press and are released through a roof vent or stack to the
outside air, sometimes undergoing treatment to reduce the emissions. Fugitive emissions
escape from the printing process (e.g., from a long web run between presses), and exit the
facility through windows and doors. It was assumed that 30% of the VOCs released to the
air were fugitive emissions, and 70% were captured by the press system and released through
a stack. It was also assumed that solvent-based ink releases would pass through a catalytic
oxidizer with a destruction efficiency of 95%, but that water-based or UV-cured ink systems
would not utilize an oxidizer. Environmental releases relate to the rates of vapor generation,
which vary depending on press speed, VOC content of the ink mixture, equipment operating
time, temperature of the ambient air and ink system, the capture efficiency of the press system,
and the destruction efficiency of the air control devices.
The calculated volatilization rates of the solvent-based inks were considerably higher than
those for the other two ink systems. The volatilization rates for water-based inks were
considerably lower than those for solvent-based inks, but the stack releases were higher
because the use of an oxidizer was not anticipated. On the other hand, the fugitive
emissions of the water-based inks were considerably lower than those for solvent-based
inks because of the lower average VOC content of water-based inks.
The UV-cured inks showed releases comparable to those of water-based inks and higher
than those of solvent-based inks. These figures were calculated with the assumption that
all VOCs would be released to the air. In reality, however, much of the volatile content
would be incorporated into the coating during the UV curing process. The decrease in
emissions under real-world conditions is unknown.
Adding solvents, reducers, extenders, cross-linkers, and other compounds to the inks
increased their volatile content, resulting in greater environmental releases. During the
CTSA performance demonstrations, solvents were added in higher quantities to solvent-
based ink formulations than to water-based and UV-cured formulations, which further
increased the releases from solvent-based inks.
Press speed greatly affected the amount of ink consumed, and thus the releases of volatile
compounds. Air releases also varied among colors within each ink system; the differences
were primarily due to different ink consumption rates, which will vary with every printing
job.
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EXECUTIVE SUMMARY
Aquatic Toxicity
Roughly half of the ink chemicals showed a medium or high aquatic toxicity (capable of
causing long-term effects to aquatic organisms, in a concentration of less than 0.1 mg/liter).
Eighteen chemicals (Table ES.6) were found to have high aquatic toxicity. Another 35
chemicals showed medium aquatic toxicity. Because the inks were not expected to be released
to the aquatic environment, water releases and subsequently related risks were not assessed.
If any of these inks are in fact released untreated to water, however, there could be aquatic
risk concern.
Table ES.6 CTSA Chemicals With High Aquatic Toxicity
Amides, tallow, hydrogenated n-Heptane
Ammonia 2-Isopropylthioxanthone
C.I. Basic Violet 1 4-Isopropylthioxanthone
molybdatephosphate
C.I. Basic Violet 1 Mineral oil
molybdatetungstatephosphate
C.I. Pigment Violet 27 Resin acids, hydrogenated,
methyl esters
Dicyclohexyl phthalate Styrene
Distillates, petroleum, Thioxanthone derivative
hydrotreated light
2-Ethylhexyl diphenyl phosphate Trimethylolpropane ethoxylate
triacrylate
Glycerol propoxylate triacrylate
PERFORMANCE
Because quality of printing is a critical need of flexographers, the CTSA conducted 18
performance tests, which examined quality aspects anticipated to be important for a broad
range of flexographic printers. (See Chapter 4 for details.)
Eleven performance demonstrations were conducted at printing facilities that volunteered to
participate, using inks donated by ink companies. The inks used were considered fairly
representative of ink types commonly in use at that time. Five ink colors (cyan, magenta, blue,
green, and white) were included, to allow testing of both process and line printing results. The
performance demonstrations were brief printing runs of a representative test image (Figure
ES.4), which was printed using wide-web presses onto three types of film substrates: oriented
polypropylene (OPP); low-density polyethylene (LDPE); and polyethylene/ethyl vinyl acetate
co-extruded film (PE/EVA). These substrates were chosen because they correspond to
important flexographic market segments. To collect baseline data, laboratory runs were also
conducted in the printing laboratory of Western Michigan University. This was done to give
printers a better sense of the actual capabilities of the ink-substrate combinations.
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EXECUTIVE SUMMARY
Figure ES.4 Test Image Used in Demonstration Runs
Performance tests were conducted on the samples from both the performance demonstrations
and the laboratory runs (Table ES.7).
Table ES.7 Performance Tests Conducted in CTSA
Adhesive lamination Ice water crinkle adhesion
Block resistance Image analysis
CIE L*a*b* Jar odor
Coating weight Mottle/lay
Coefficient of friction (COF) Opacity
Density Rub resistance
Dimensional stability Tape adhesiveness
Gloss Trap
Heat resistance/heat seal Uncured residue (UV-cured inks only)
Performance Findings
The quality of performance varied widely across ink systems, substrates, and ink
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EXECUTIVE SUMMARY
formulations. No clear evidence emerged that any one ink system performed best overall. For
example,
?Water-based inks outperformed solvent-based inks on both LDPE and PE/EVA
substrates. Solvent-based inks performed better than water-based inks on the adhesive
lamination test.
?Gloss was highest for solvent-based inks on PE/EVA. Gloss was low on UV-cured
inks, despite the fact that high gloss is considered to be a strength of UV finishes.
?Odors varied in both strength and type across both ink and substrate type.
?Mottle was significantly higher for water-based inks, as well as for blue inks overall.
?UV-cured inks displayed good resistance to blocking, particularly on PE/EVA and no-
slip LDPE.
?UV-cured inks displayed relatively good trapping.
?Mottle results for UV-cured inks were better than that of the water-based inks and
comparable to that of the solvent-based inks.
?Coating weight was greater for UV-cured inks, despite lower ink consumption.
?Some UV-cured inks showed unimpressive results on the rub resistance and tape
adhesiveness tests.
The variances in results show the importance of a number of factors in the performance of
these inks:
?Substrate type
?Type and amount of vehicle (e.g., solvent in solvent-based ink and water in
water-based ink), as well as press-side solvents and additives
?Functional ink-substrate interactions such as wetting and adhesion
Table ES.8 lists the ink system, color, and substrate combinations showing "best in class"
performance for selected tests that were run. Most of these tests do not have industry
standards, and for some tests the determination of a better or worse result can depend on the
needs of a specific printing situation. (The "worst" score is also provided, but only to give an
indication of the large range in scores on almost all tests.) Due to a variety of issues that
occurred at volunteer facilities, not all ink systems received all tests.
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EXECUTIVE SUMMARY
Table ES.8 Selected "Best in Class" Performances on Flexography CTSA Tests
Worst Scoreba
Test Best Score Ink System Substrate Color
solventb N/Ac
Adhesive .3040 kg OPP .2575 kg (lowest)
lamination (highest)
Block resistance 1.0 (lowest) UV no slip LDPE N/A 3.2 (highest)
Density 2.17 (highest) UV high slip LDPE blue 1.09 (lowest)
Gloss 59.08 (highest) solvent PE/EVA N/A 32.31 (lowest)
solventb
Heat resistance 0 failures OPP N/A 24 failures (most)
(lowest)
Ice water crinkle no ink removal solvent, LDPE, N/A 30% ink removal
(least) water PE/EVA (most)
324 :m2 dot 1050 :m2 (highest)
Image analysis solvent PE/EVA cyan
area (lowest)
Mottle 47 (lowest) UV no slip LDPE green 812 (highest)
Rub resistance, 0 failures at 10 water, LDPE N/A failure at 2.2
wet strokes solvent (PE/EVA) strokes
a
This score represents the opposite end of the range of all scores received on this test for all ink systems
tested.
b
UV-cured samples were not tested.
c
N/A indicates that the test results were not color-specific.
These performance demonstrations were completed in 1997, since which time flexographic
printing technology for UV-cured inks has made significant advances. The test results of this
CTSA provide a snapshot of UV technology early in its technical development but do not
necessarily lead to any conclusions about current or potential abilities of UV inks. In fact, just
as for solvent-based and water-based inks, no one test can provide a reliable or accurate
indicator of overall quality for any printer. Printers need to consider a variety of different
factors in determining acceptable quality. These factors -- among them cost, health and
environmental risks, energy use, and pollution prevention opportunities -- are discussed in
other chapters of this CTSA.
In addition, because performance is a function of many factors -- including equipment, ink,
substrate, and operator experience -- a printing facility that conducts its own performance
tests might obtain different results than the CTSA. This potential for variability is
demonstrated by the performance results, which differed widely among formulations within
the same ink system. The performance variability indicates that there may not be one best
overall choice of an ink system for all performance conditions and applications. A
flexographic printer cannot simply assume that one ink system or ink-substrate combination
will be best-suited to the firm's overall needs. Careful testing of a potential ink system on
the various substrates that a printer will be using most often is critical to obtaining desired
quality on a consistent basis.
UV curing technology, especially as it pertains to wide-web printing on film substrates, was
in a developmental stage at the time these tests were conducted. The test results in this CTSA
provide a snapshot of UV technology early in its technical development but do not necessarily
lead to any conclusions about current or potential abilities of UV-cured inks. Since that time,
improvements to this ink system have been made on several fronts. In addition, manufacturers
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EXECUTIVE SUMMARY
of both solvent-based and water-based inks have made improvements in formulations since
the performance demonstrations were completed. In particular, changes that have been made
to resins and slip additives of inks may yield improved adhesive characteristics and other
traits.
COSTS
A number of costs are important to facility profitability and have the potential to highlight
differences among ink systems. The study evaluated the costs of materials (ink and press-side
additions), labor, capital, and energy. Substrate costs were not evaluated because they are not
dependent upon ink use. Input quantities for materials were obtained during the performance
demonstrations. Suppliers provided information about costs.
This analysis averages industry information, and therefore it may not reflect the actual
experience of any given printing facility in this short-term demonstration. For example, the
efficiencies of a long run with familiar products were not achieved. Also, press speed under
many printing conditions is expected to be different (and in general, higher) than in this
analysis. While this study focused on those costs that typically account for the majority of
total costs, other important costs (e.g., waste disposal, regulatory compliance, insurance,
storage, clean-up, and permitting) should not be overlooked. In addition, press maintenance
and other conditions may affect ink usage, and therefore ink costs.
Cost Findings
Highlights of the cost analysis include the following:
?Materials were the highest cost category for the CTSA printers among the categories
studied. Water-based inks had the lowest material costs of the three systems, showing
a higher mileage than solvent-based inks and a much lower per-pound cost than UV-
cured inks.
?The analysis did not consider start-up and clean-up labor, and the press speed was
assumed to be the same for all three ink systems. (Labor costs would have differed
by ink system if the analysis had captured the costs of preparation, cleanup, etc.)
Therefore, labor cost (wages and benefits for two press operators) was identical in
the study for all three systems.
?Energy cost (electricity and natural gas) was highest for UV-cured inks. The water-
based system showed the lowest energy cost because it assumed no energy use by
oxidizers. If oxidizers were to be used, much of the water-based system's cost
advantage would disappear.
?Water-based inks had the lowest capital costs (press and other required components),
because the water-based printers did not use oxidizers. Solvent-based inks showed
higher capital costs because of the expense of oxidizers. Because UV uses lamps to
cure inks, this system also had higher capital costs. However, the capital costs of a
new press for all three technologies were relatively similar. Therefore, they are likely
to be only a small factor in the selection of an ink system.
?Assuming a press speed of 500 feet per minute, the CTSA found that the total cost
was lowest for the water-based system, with the solvent-based and UV-cured systems
costing on average 24% and 38% more respectively (Table ES.9).
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EXECUTIVE SUMMARY
Table ES.9 Cost Averages (per 6,000 square feet, at 500 feet per minute)
Ink system Materials Labor Energ Capital Total
(Ink & y
Additions)
Solvent-based $15.29 $5.29 $0.53 $11.87 $32.98
Water-based $9.55 $5.29 $0.35 $11.41 $26.60
UV-cured $18.63 $5.29 $1.03 $11.87 $36.82
Generally speaking, press speed appears to be the most important driver of a printer's
total cost, because all costs except that of ink and substrate were impacted by press speed.
Thus, press speed is a critical variable in maximizing profitability of flexographic
printing, Therefore, if a facility can run one ink system (or one formulation) notably faster
than another while meeting product quality standards, the faster system or formulation
will probably also be the most cost-effective system.
RESOURCE USE AND ENERGY CONSERVATION
By minimizing resource and energy use, printers can improve both their bottom line and the
environment. To identify potential issues on which printers may wish to focus their efforts,
the study investigated several sources of resource consumption (Table ES.10) and pollutant
generation related to the three ink systems studied:
?resources consumed,
?energy used,
?energy-related emissions generated by each ink system, and
?possible environmental impacts of energy-related impacts.
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EXECUTIVE SUMMARY
Table ES.10 Categories of Consumption Studied
Category of Specific elements Comments
Consumption Included
Printing-related Inks, solvents, and press- The ink consumption figures were
resources side additives calculated during the performance
demonstrations, and were affected by
several site-specific factors, such as type of
cleaning equipment, anilox roll size, and
the level of surface tension of the
substrate.
Energy Natural gas and electricity Equipment vendors estimated energy
consumed by to run presses presses and requirements in kilowatts for electricity and
the printing of ancillary press equipment in Btus/hr for natural gas. These estimates
each ink- (oxidizers, hot air dryers, were used instead of actual site-specific
substrate drying ovens, corona data to calculate energy consumption for
combination treaters, UV-curing lamps the study.
and coolers)
The energy-related emissions from printing each ink-substrate combination include carbon
dioxide, carbon monoxide, hydrocarbons, nitrogen oxides, particulate matter, dissolved
solids, solid wastes, sulfur oxides, and sulfuric acid. With natural gas, the emissions are
generated at the printing facility, but with electricity, the emissions are generated off-site
at the power plant. Either way, the printing facility needs to know environmental impacts
that can be attributed to the printing processes used. This allows a facility to plan ways
to reduce energy use and the related environmental releases that are generated by different
types of energy. Employing more energy-efficient technologies may benefit printers by
reducing production costs, lowering energy-related emissions, and improving the facility's
public image.
Resources Used and Emissions Generated
The study examined various specific inputs to the printing processes, including the press units,
oxidizers, hot air dryers, drying ovens, corona treaters, UV-curing lamps, and coolers. When
all of these were taken into consideration,
?The energy consumed was estimated to be lowest for the water-based system because
no oxidizers or curing lamps were used. The solvent-based system, which used
oxidizers to destroy stack emissions, consumed the most energy.
?The estimated emissions were lowest for the water-based system, because much of
its energy derives from natural gas, which releases less emissions per unit of energy
than does electricity. Although the UV-cured system consumed little more energy
than the water-based system, it was estimated to result in the highest total energy-
related emissions, because all of its energy comes from electricity.
Table ES.12 lists the amounts of resources consumed by each ink system, as well as the
amounts of environmental releases of pollutants associated with energy production. Results
are reported in terms of grams per 6000 square feet of substrate, which allows a direct
comparison of pollutants generated by the different ink systems.
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EXECUTIVE SUMMARY
Table ES.11 Average Resource Use and Energy-Related Emissions
(at 500 fpm)
Energy-Related
Resources
Ink System Energy Consumed Emissions
Consumed a
per 6,000 ft2 (Btu) b, C Generated
(lb/6,000 ft2)
(g/6000 ft2)d
Solvent-based 8.53 100,000 10,000
Water-based 4.14 73,000 6,800
UV-cured 2.16 78,000 18,000
a
Ink consumption figures were averaged from the total costs of ink, solvents, and additives for all
three substrates in Table 6.4; energy consumption figures are from Table 6.11; and energy-related
emissions are from Table 6.21.
b
Electrical energy was converted to Btus using the factor of 3,413 Btu per kW-hr.
C
Electricity was generated offsite.
d
Energy-related emissions were calculated using a computer model rather than by capturing and
analyzing actual emissions from the facilities.
Pollutants that were released during energy production of the CTSA printing runs include
carbon dioxide, carbon monoxide, dissolved solids, hydrocarbons, nitrogen oxides, particulate
matter, solid wastes, sulfur oxides, and sulfuric acid. Again, because UV curing relies
exclusively upon electricity, this ink system was shown to generate more of the pollutants that
are associated with this form of energy (such as nitrogen oxides, carbon dioxide, and sulfur
oxides), some of which affect environmental air quality and are important to global climate
change. Energy use was analyzed using the methodology press speed (500 feet per minute) and
actual press speed. The amount of pollutants generated was associated with press speed, and
higher press speed produced fewer grams of pollutants for the same number of feet of
substrate.
Overall, the water-based ink system generated the fewest grams of pollutants per 6000 feet
of substrate printed, and the UV-cured ink system generated the most. Most of these pollutants
fall into a category called "use impairment impacts," which includes global warming
compounds, acid rain precursors, smog formers, corrosives, dissolved solids, odorants, and
particulates.
CHOOSING AMONG FLEXOGRAPHIC INKS
This section summarizes important findings of the Flexographic Inks CTSA by ink system,
and identifies ways to use the CTSA to incorporate health and environmental impacts of
flexographic ink chemicals in business decision-making.
Choosing an ink system, an ink product line (e.g., solvent-based ink #1), or a specific ink
formulation (e.g., color within a product line, such as solvent-based ink #1 white) is not a
simple task. The study found substantial variation within each ink system in health and
environmental impacts, performance, cost, and resource use. Each aspect of ink use has
implications -- important environmental health and safety implications as well as
performance, cost, and energy use . Every product line analyzed in the CTSA included
chemicals that are associated with multiple clear health risk concerns for flexographic press
workers (Table 8.3). Each ink system also was found to have safety hazards for the
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EXECUTIVE SUMMARY
workplace (flammability, ignitability, reactivity, or corrosivity concerns). All of the
formulations released VOCs and sometimes HAPs as well (Table 8.4).
Highlights of CTSA Findings
Solvent-based Inks
?The solvent-based ink system, on average, had total operating costs that were lower
than those of UV-cured inks but higher than those of water-based inks. This higher
cost can be attributed mostly to higher material and capital costs of solvent-based
technologies. In particular, average material costs for solvent-based systems (per
6,000 square feet of image) were approximately $5.00 higher than those for water-
based systems.
?The solvent-based system on average outperformed both water-based and UV-cured
systems. This system was the best with respect to gloss and trap and among the best
on the other three summary performance tests.
?On average, solvent-based inks contained two to four chemicals with a clear concern
for occupational risk, slightly higher than the ranges for water-based and UV-cured
inks. This may indicate a higher occupational risk.
?Public health risk was evaluated through releases of smog-related compounds, VOC
and HAP content, and the systemic and developmental risks to the general
population. Despite the fact that this system used oxidizers, emissions were
calculated to be considerably higher than the emissions of the other systems. VOC
content was, as expected, much higher than either of the two other systems. This
system did not contain any HAPs. For general population risks, two chemical
categories in one solvent based ink (ink #2) contained chemicals that presented a
potential concern for risk.
?In terms of process safety, solvent-based inks had more concerns than the other
systems, although the results for UV-cured inks were incomplete. Only solvent-
based inks presented an ignitability concern; they also presented a higher
flammability concern than water-based inks.
?Solvent-based inks were shown to use more energy to produce the same square
footage of image.
Water-based Inks
?Operating costs were lowest for the water-based ink product lines. In fact, in all
cost categories, water-based ink systems had the lowest average cost. Cost savings
were particularly pronounced for material costs.
?Though water-based ink formulations #2 and #4 had the best mottle scores of all
product lines, overall the water-based inks did not perform as well as the solvent-
based inks in the five summary performance categories. The system also was
outperformed by the UV-cured inks in three categories. While this may indicate a
lower quality product, it is important to note that in many cases the differences were
small and may be insignificant.
?In the occupational health area, water-based inks presented a lower average number
of chemicals with a clear concern for risk per product line, indicating a better chance
of reducing occupational health risks compared to solvent-based inks.
?The amount of smog-related emissions that resulted from ink releases and energy
production with the water-based system was considerably lower than that from
solvent-based system, and was comparable to that from the UV-cured system.
Water-based inks had a much lower VOC content than solvent-based inks, but were
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EXECUTIVE SUMMARY
the only inks that contained HAPs.
? Like with solvent-based inks, printers often add VOC solvents and additives at press
side to water-based inks. In substantial amounts, these materials compromise the
low-VOC content of the ink and can pose clear pressroom worker risks. At one site
using water-based inks (Site 3), over half of the emissions resulted from materials
added at press-side.
? The safety of water-based inks was better than that of solvent-based inks. There
was no indication of ignitability or reactivity. However, water-based inks had a
higher flammability risk than UV-cured inks.
? As for energy expenditures, water-based inks had the lowest average energy use.
UV-cured Inks
?The UV-cured inks had the highest average operating costs. However, since it is a
new developing technology for wide-web film, these costs are likely to fall as the
technology develops. The biggest cost differential was the material costs, falling
approximately $8.00 per 6,000 ft2 of image above the average costs for water-based
inks. It is also worth noting that energy costs of the UV systems were considerably
higher -- nearly two times the cost for solvent-based inks and nearly three times the
cost for water-based inks.
?The performance of the UV-cured inks was generally worse than that of solvent-
based inks, though this system had better blocking resistance, and individual product
lines had ice water crinkle and mottle results that were equal to the solvent-based
results. The performance results were slightly better than those of the water-based
inks.
?The UV-cured inks presented the lowest chance of occupational health risk, and with
respect to public health, had the lowest HAP and VOC contents. A couple of SAT-
analyzed compounds present a potential concern for general population risk,
however, indicating that research on some compounds is needed.
?Safety hazard data were incomplete for UV inks. However, UV inks were the only
inks that present the potential for reactivity.
?Finally, the energy used by UV-cured systems was approximately 22% less than that
of solvent-based inks, and was only slightly higher than that of the water-based inks.
The air releases associated with the energy production were higher than solvent-
based inks, however, because all energy required by the UV system was derived
from electricity -- a more pollution-intensive energy source in comparison to natural
gas.
Choosing Cleaner, Safer Ink Chemicals
Because of the importance of the specific formulation to the results of the flexographic ink
study, printers are advised to pay as much attention to selecting the "cleanest" formulation
within an ink system as to the ink system itself.
Table 3-1 provides toxicity and risk screening information on the chemical substances that
were included in this study. Many of the substances were found in multiple ink formulations
and are likely to be found in other inks. Whether choosing amongst the ink systems or
choosing an ink formulation, it is important to consider the health, safety, and environmental
impacts of the chemical substances that make up a formulated product. The DfE
Flexographic Inks CTSA can serve as a first step in bringing a more positive environmental
profile into the printing shop. The DfE Program encourages printers and the ink manufacturer
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EXECUTIVE SUMMARY
and distributors to actively engage in a dialog on "getting the right mix" in the print shop.
Table 8.13 summarizes hazard and risk information for every chemical category and chemical
in the study. Flexographic professionals can use this table to compare chemicals within and
across chemical categories, which can help to identify possible alternatives for a chemical that
shows concerns. As an example, Table ES.12 below shows a partial entry for ethylene glycol
ethers from Table 8.13. The Hazard columns indicate that ethylene glycol ethers have
moderate (M) and moderate-high (M-H) hazards, and the Occupational Risk column shows
several instances of clear risk concern for this chemical category under the conditions of use
analyzed in this study.
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EXECUTIVE SUMMARY
Table ES.12 Summary of Hazard and Risk Data by Chemical Category (Excerpt)
Occupational Riskc
Hazard
Ink Data
Chemicals
System Source Dermala Inhalationab
Aquatic Dermal Inhalation
Ethylene glycol ethers
Water Alcohols, C11-15- SAT M M/M M/M clear n.e.
secondary,
ethoxylated
68131-40-8
Butyl carbitol Tox L L/L M/L clear clear
112-34-5
Ethoxylated SAT L L-M/NA L-M/NA potential n.e.
tetramethyldecyndi
ol
9014-85-1
Ethyl carbitol Tox L M-H/L M-H/L clear clear
111-90-0
Polyethylene glycol Tox L L/NA L/NA potential n.e.
25322-68-3
a
The first letter(s) represents systemic concern, the second represents developmental concerns. L= Low; M =
Medium; H = High; NA = No data or information are available; n.e. = No Exposure
b
Inhalation hazard information was not included for compounds that are not expected to be volatile (i.e., that
have a vapor pressure <0.001 mmHg).
c
Dermal occupational risk concern ratings are applicable for press and prep room workers; inhalation risk
concern ratings are applicable for press room workers. The risk concern levels shown here represent the highest
observed risk rating.
Other Suggestions for Reducing Impacts of Flexographic Inks
DfE partners, particularly the Steering Committee, include the major trade associations in the
flexographic ink industry. These partners are an excellent source of information on both
industry trends and concerns. Their willingness to maintain continued partnership with DfE
over the years demonstrates their commitment to providing the industry with sound
environmental information. Trade associations are considered essential DfE partners during
a project as well as for industry-wide communication and implementation of project results.
Associations are key to sharing information, including incentives to making change and
recognition of businesses that have overcome obstacles.
In addition to your trade association, other useful resources include the EPA's Office of
Pollution Prevention and Toxic's (OPPT) website. Please visit the site
to find tools, models, and chemical
information for better understanding chemicals.
Also, important information on chemical categories can be found at the EPA's New Chemicals
website . The chemical categories
broadly describe potential concerns for substances that may fall into a specific chemical
category. The category also describes bounds for determining whether a specific chemical
substance, that would generally fall into a category, actually might be considered of concern.
A category statement describes the molecular structure a chemical might have to be included
in the category as well as boundary conditions such as molecular weight, equivalent weight,
the log of the octanol/water partition coefficient (log P), or water solubility, that would
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EXECUTIVE SUMMARY
determine inclusion in (or exclusion from) a category, and standard hazard and fate tests to
address concerns for the category. Currently, there are a total of 45 categories.
A few excellent secondary sources of chemical information include the following:
?The Hazardous Substances Data Bank, in TOXNET:
?Agency for Toxic Substances and Disease Registry (ASTDR):
?The National Library of Medicine Toxicology and Environmental Health
Specialized Information Services:
?TOXLINE: The National Library of Medicine's extensive collection of online
bibliographic information covering the biochemical, pharmacological, physiological,
and toxicological effects of drugs and other chemicals.
?Integrated Risk Information System (IRIS):
The DfE website (www.epa.gov/dfe) may also serve as a source of information on other
chemical substances. The DfE Program has reviewed many other substances in similar
cleaner technology evaluations, including previous partnerships focused on the activities of
screen and lithographic printers.
There is another message here in understanding chemicals in the workplace: To be a
proactive decision-maker, it is critical to have the best information available. Building as
well as choosing a product formulation with a more positive environmental profile may
require extra care and scrutiny, especially when selecting raw materials. A material data
safety sheet (MSDS) and the product label provide an excellent starting place for
understanding the potential impacts of a chemical; however, the MSDS or label may not
provide all the information needed to make a better choice. Often, chemicals are generically
described by chemical class or, by trade name. Structural and other differences in chemicals
of the same general class and makeup may not be apparent from product literature or labels,
especially for imported substances. Descriptions in distributor or supplier literature and
catalogs may define a chemical type but not detail a chemical's actual structure (e.g.,
whether a carbon chain is branched or linear ?a key distinction from an environmental
standpoint since linear chains biodegrade more rapidly than branched). Also, sales materials
may only list trade names, often an imprecise descriptor, since a name might remain the same
while the actual product composition may change. The databases and resources described
above identify chemical substances by specific chemical name; it is important to get correct
chemical identify information that includes Chemical Abstract Service (CAS) names and
CAS numbers when doing research on chemical formulations.
DfE encourages you to visit our website for more information on the DfE formulator
initiative, at http://www.epa.gov/dfe/projects/formulat/index.htm. The DfE Program offers
partnership and recognition to companies that act as environmental stewards by improving
the environmental profile of their formulated products and processes.
Table ES.13 presents some suggestions for how flexographic professionals can quickly and
easily take actions that may reduce the health and environmental impacts of using
flexographic inks. The CTSA also includes more general ways to implement pollution
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prevention related to the flexographic industry.
Table ES.13 Ways to Reduce Environmental and Health Impacts of Flexographic Inks
Suggestion Printers Formulators Other
(Technology
Assistance
Providers,
Colleges, etc.)
Read flexographic CTSA materials to X X X
become familiar with environmental and
health impacts of chemicals in inks.
Select the cleanest inks that make business X
sense. Minimize use of hazardous inks.
Minimize the need for and use of press-side X X
solvents and other additives.
Maximize good ventilation, particularly in the X
prep and press rooms.
Ensure that all workers who handle inks wear X
butyl or nitrile gloves, to minimize exposure
to chemicals.
Ensure that all pollution control devices are X
maintained properly and work correctly at all
times.
Identify ways to improve operations and X X
environmental performance by looking at all
steps in the printing process throughout the
facility.
Develop comprehensive safe working policies X X
and practices for inks, and ensure that
workers follow them.
Minimize the amount and number of X
hazardous ingredients in inks.
Work to make environmental and health X
information about inks more accessible and
understandable.
Support research on untested and X X X
inadequately tested flexographic ink
chemicals, especially those with clear or
potential risk concerns and those that are
produced in high quantities (high production
volume chemicals).
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EXECUTIVE SUMMARY
REFERENCES
1. U.S. Census, 1999 Survey of Manufactures.
2. U.S. Census. 1997. Commercial Flexographic Printing.
3. Flexo, December 1998. "1999 Industry Forecasts," p. 32.
4. U.S. Census. 1997. Commercial Flexographic Printing.
5. National Association of Printing Ink Manufacturers. 2001 State of the
Industry Report, p 4 (Printing Ink 2000 Market).
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