Why do we offer safe fabrics?

3 10 2016

Why do we say we want to change the textile industry?  Why do we say we want to produce fabrics in ways that are non-toxic, ethical and sustainable?  What could be so bad about the fabrics we live with?

The textile industry is enormous, and because of its size its impacts are profound.  It uses a lot of three ingredients:

  • Water
  • Chemicals
  • Energy

Water was not included in the 1947 UN Universal Declaration of Human Rights because at the time it wasn’t perceived as having a human rights dimension. Yet today, corporate interests are controlling water, and what is known as the global water justice movement is working hard to ensure the right to water as a basic human right.(1) Our global supply of fresh water is diminishing – 2/3 of the world’s population is projected to face water scarcity by 2025, according to the UN. Our global water consumption rose six fold between 1900 and 1995 – more than double the rate of population growth – and it’s still growing as farming, industry and domestic demand all increase.

The textile industry uses vast amounts of water throughout all processing operations.  Almost all dyes, specialty chemicals and finishing chemicals are applied to textiles in water baths.  Most fabric preparation steps, including desizing, scouring, and bleaching use water.  And each one of these steps must be followed by a thorough washing of the fabric to remove all chemicals used before moving on to the next step.  The water is usually returned to our ecosystem without treatment – meaning that the wastewater, which is returned to our streams, contains all of the process chemicals used during milling.  This pollutes the groundwater.  As the pollution increases, the first thing that happens is that the amount of useable water declines.  But the health of people depending on that water is also at risk, as is the health of the entire ecosystem.

With no controls in place to speak of to date, there are now 405 dead zones in our oceans.  Drinking water even in industrialized countries, with treatment in place, nevertheless yields a list of toxins when tested – many of them with no toxicological roadmap.  The textile industry is the #1 industrial polluter of fresh water on the planet – the 9 trillion liters of water used annually in textile processing is usually expelled into our rivers without treatment and is a major source of groundwater pollution.  Now that virtual or “embedded” water tracking is becoming necessary in evaluating products, people are beginning to understand when we say it takes 500 gallons of water to make the fabric to cover one sofa.  We want people to become aware that when they buy anything, and fabric especially, they reinforce the manufacturing processes used to produce it.  Just Google “Greenpeace and the textile industry” to find out what Greenpeace is doing to make people aware of this issue.

Over 8,000 chemicals are used in textile processing, some so hazardous that OSHA requires textile scraps be handled as hazardous waste.   The final product is, by weight, about 23% synthetic chemicals – often the same chemicals that are outlawed in other products.  The following is by no means an all-inclusive list of these chemicals:

  • Alkylphenolethoxylates (APEOs), which are endocrine disruptors;
    • o Endocrine disruptors are a wide range of chemicals which interfere with the body’s endocrine system to produce adverse developmental, reproductive, neurological and immune effects in both humans and wildlife; exposure us suspected to be associated with altered reproductive function in both males and females, increased incidence of breast cancer, abnormal growth patterns and neurodevelopmental delays in children.(2)
  • Pentachlorophenols (PCP)
    • o Long-term exposure to low levels can cause damage to the liver, kidneys, blood, and nervous system. Studies in animals also suggest that the endocrine system and immune system can also be damaged following long-term exposure to low levels of pentachlorophenol. All of these effects get worse as the level of exposure increases.(3)
  • Toluene and other aromatic amines
    • carcinogens (4)
  • Dichloromethane (DCM)
    • Exposure leads to decreased motor activity, impaired memory and other neurobehavioral deficits; brain and liver cancer.(5)
  • Formaldehyde
    • The National Toxicology Program named formaldehyde as a known human carcinogen in its 12th Report on Carcinogens.(6)
  • Phthalates –
    • Associated with a range of effects from liver and kidney diseases to developmental and reproductive effects, reduced fetal weight.(7)
  • Polybrominated diphenyl ethers (PBDE’s)
    • A growing body of research in laboratory animals has linked PBDE exposure to an array of adverse health effects including thyroid hormone disruption, permanent learning and memory impairment, behavioral changes, hearing deficits, delayed puberty onset, decreased sperm count, fetal malformations and, possibly, cancer.(8)
  • Perfluorooctane sulfonates (PFOS)
    • To date, associations have been found between PFOS or PFOA levels in the general population and reduced female fertility and sperm quality, reduced birth weight, attention deficit hyperactivity disorder (ADHD), increased total and non-HDL (bad) cholesterol levels, and changes in thyroid hormone levels.(9)
  • Heavy metals – cadmium, lead, antimony, mercury among others
    • Lead is a neurotoxin (affects the brain and cognitive development) and affects the reproductive system; mercury is a neurotoxin and possibly carcinogenic; cadmium damages the kidneys, bones and the International Agency for Research on Cancer has classified it as a human carcinogen; exposure to antimony can cause reproductive disorders and chromosome damage.

The textile industry uses huge quantities of fossil fuels  –  both to create energy directly needed to power the mills, produce heat and steam, and power air conditioners, as well as indirectly to create the many chemicals used in production.  In addition, the textile industry has one of the lowest efficiencies in energy utilization because it is largely antiquated.  For example, steam used in the textile manufacturing process is often generated in inefficient and polluting coal-fired boilers.  Based on estimated annual global textile production of 60 billion kilograms (KG) of fabric, the estimated energy needed to produce that fabric boggles the mind:  1,074 billion KWh of electricity (or 132 million metric tons of coal).  It takes 3886 MJ of energy to produce 25 yards of nylon fabric (about the amount needed to cover one sofa).  To put that into perspective, 1 gallon of gasoline equals 131 MJ of energy; driving a Lamborghini from New York to Washington D.C. uses approximately 2266 MJ of energy.(10)

Today’s textile industry is also one of the largest sources of greenhouse gasses on the planet: in the USA alone, it accounts for 5% of the country’s CO2 production annually; China’s textile sector alone would rank as the 24th– largest country in the world.(11)

We succeeded in producing the world’s first collection of organic fabrics that were gorgeous and green – and safe.    In 2007, those fabrics won “Best Merchandise” at Decorex (www.decorex.com).    In 2008, our collection was named one of the Top Green Products of 2008 by BuiltGreen/Environmental Building News. As BuiltGreen/EBN takes no advertising dollars, their extensive research is prized by the green building industry (www.buildinggreen.com).

We are a tiny company with an oversized mission.  We are challenged to be a triple bottom line company, and we want to make an outsized difference through education for change  – so that a sufficiently large number of consumers will know which questions to ask that will force change in an industry.  We believe that a sufficiently large number of people will respond to our message to force profound positive change: by demanding safe fabric, produced safely, our environment and our health will be improved.

The issues that distinguish us from other fabric distributors, in addition to offering fabrics whose green pedigree is second to none:

    1. We manage each step of the production process from fiber to finished fabric, unlike other companies, which buy mill product and choose only the color palette of the production run.    Those production process steps include fiber preparation, spinning, weaving, dyeing, printing and finishing; with many sub-steps such as sizing and de-sizing, bleaching, slashing, etc.
    2. We educate consumers and designers on the issues that are important to them – and to all of us. Our blog on the topic of sustainability in the textile industry has grown from about 2 hits a day to 2,000, and is our largest source of new customers.
    3. We are completely transparent in all aspects of our production and products.    We want our brand to be known not only as the “the greenest”, but for honesty and authenticity in all claims.  This alignment between our values, our claims and our products fuels our passion for the business.
    4. We are the only collection we know of which sells only “safe” fabrics.

We serve multiple communities, but we see ourselves as being especially important to two communities:  those who work to produce our fabric and those who use it, especially children and their parents.

    • By insisting on the use of safe chemicals exclusively, we improve the working conditions for textile workers.  And by insisting on water treatment, we mitigate the effects of even benign chemicals on the environment – and the workers’ homes and agricultural land.  Even salt, used in copious amounts in textile processing, will ruin farmland and destroy local flora and fauna if not neutralized before being returned to the local waters.
    • For those who use our fabric, chemicals retained in the finished fibers do not add to our “body burden “, which is especially important for children, part of our second special community.  A finished fabric is, by weight, approximately 23% synthetic chemicals. Those chemicals are not benign.  Textile processing routinely uses chemicals with known toxic profiles such as lead, mercury, formaldehyde, arsenic and benzene – and many other chemicals, many of which have never been tested for safety.

Another thing we’d like you to know about this business is the increasing number of people who contact us who have been harmed by fabric (of all things!) because we represent what they believe is an honest attempt at throwing light on the subject of fabric processing.   Many are individuals who suffer from what is now being called “Idiopathic Environmental Intolerance” or IEI (formerly called Multiple Chemical Sensitivity), who are looking for safe fabrics.  We’ve also been contacted on behalf of groups, for example,   flight attendants, who were given new uniforms in 2011, which caused allergic reactions in a large number of union members.

These incidences of fabric-induced reactions are on the rise.   As we become more aware of the factors that influence our health, such as we’re seeing currently with increased awareness of the effects of interior air quality, designers and others will begin to see their way to specifying “safe” fabrics  just as their code of ethics demands.(12)  We feel certain that the trajectory for such an important consumer product as fabric, which surrounds us most of every hour of the day, will mimic that of organic food.

We say our fabrics are luxurious – because luxury has become more about your state of mind than the size of your wallet. These days, people define luxury by such things as a long lunch with old friends, the good health to run a 5K, or waking up in the morning and doing exactly what you want all day long.  In the past luxury was often about things.  Today, we think it’s not so much about having as it is about being knowledgeable about what you’re buying – knowing that you’re buying the best and that it’s also good for the world.  It’s also about responsibility: it just doesn’t feel OK to buy unnecessary things when people are starving and the world is becoming overheated.  It’s about products being defined by how they make you feel –  “conscious consumption” – and giving you ways to find personal meaning and satisfaction.

 

(1) Barlow, Maude, Blue Covenant: The Global Water Crisis and the coming Battle for the Right to Water, October 2007

(2)World Health Organization, http://www.who.int/ceh/risks/cehemerging2/en/

(3)Agency for Toxic Substances & Disease Registry 2001, https://www.atsdr.cdc.gov/phs/phs.asp?id=400&tid=70

(4)Centers for Disease Control and Prevention, Publication # 90-101; https://www.cdc.gov/niosh/docs/90-101/

(5)Cooper GS, Scott CS, Bale AS. 2011. Insights from epidemiology into dichloromethane and cancer risk. Int J Environ Res Public Health 8:3380–3398.

(6)National Toxicology Program (June 2011). Report on Carcinogens, Twelfth Edition. Department of Health and Human Services, Public Health Service, National Toxicology Program. Retrieved June 10, 2011, from: http://ntp.niehs.nih.gov/go/roc12.

(7)Hauser, R and Calafat, AM, “Phthalates and Human Health”, Occup Environ Med 2005;62:806–818. doi: 10.1136/oem.2004.017590

(8)Environmental Working Group, http://www.ewg.org/research/mothers-milk/health-risks-pbdes

(9)School of Environmental Health, University of British Columbia; http://www.ncceh.ca/sites/default/files/Health_effects_PFCs_Oct_2010.pdf

(10) Annika Carlsson-Kanyama and Mireille Faist, 2001, Stockholm University Dept of Systems Ecology, htp://organic.kysu.edu/EnergySmartFood(2009).pdf

(11)Based on China carbon emissions reporting for 2010 from Energy Information Administration (EIA); see U.S. Department of Energy, Carbon Emissions from Energy Generation by Country, http://www.eia.gov/ cfapps/ipdbproject/IEDIndex3.cfm?tid=90&pid=44&aid=8 (accessed September 28, 2012). Estimate for China textile sector based on industrial emissions at 74% of total emissions, and textile industry
as 4.3% of total industrial emissions; see EIA, International Energy Outlook 2011, U.S. Department of Energy.

(12)Nussbaumer, L.L, “Multiple Chemical Sensitivity: The Controversy and Relation to Interior Design”, Abstract, South Dakota State University

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Textile printing and the environment

27 01 2012

Given the large size of the printing industry, and the extraordinary volume of chemicals it consumes, it is not surprising that it also generates a significant amount of pollution.  Gaseous emissions have been identified as the second greatest pollution problem (after effluent quality) for the textile industry – and these are largely generated in printing. Speculation concerning the amounts and types of air pollutants emitted from textile operations has been widespread but, generally, air emission data for textile manufacturing operations are not readily available. Air pollution is the most difficult type of pollution to sample, test, and quantify in an audit.[1]  According to the U.S. EPA, the printing industry releases 99% of its total Toxic Release Inventory (TRI) poundage to the air, while the remaining one percent of releases are split between water and land disposal. This release profile differs significantly from other TRI industries which average approximately 60% to air, 30% to land, and 10% to water release respectively. Average VOC emissions per textile print line are 130 Mg (tons)/year for roller and 29 Mg/year for flat and rotary screen.[2]

In 1995, more than 41 million pounds of toxic compounds were transferred or released into the environment by the printing industry in the United States alone.  The table below shows some of the  polluting chemicals used by the textile printing industry.  All ten are petroleum-derived.

Chemical Releases and   transfers in millions of pounds
Toluene 4.2
Methyl Ethyl   Ketone 6.3
Glycol Ethers 0.4
Xylene 0.2
Methyl   Isobutyl Ketone 0.6
Methanol 0.3
1,1,1-Trichloroethane 0.3
Ethylene   Glycol 0.5
Dichloromethane 0.1

Source: EPS: Profile of the Textile Industry, EPA/310-R-97-009, September 1997

These VOC emissions are high because of the great quantity of solvents used in the industry. The volatility that helps minimize ink drying times also presents a health and safety risk.  The solvents used in the printing pastes are typically respiratory, skin and eye irritants. But there are also more dire consequences – for example, a study done on Indian printing working has found abnormal changes in their chromosomes.(3)  With such a high percentage of the paste being volatile, solvent vapors will be released during printing and will be present throughout the printing production area. Also, the fabric will continue to off-gas solvents after the material has been printed, especially if it has been rolled up.  The Sector Notebook  gives a short synopsis of these chemicals, and I’ve excerpted a few here:

  • Toluene, although used primarily as a solvent,  is also used throughout printing for cleanup purposes. Toluene contributes to the formation of ozone in the atmosphere; studies have shown that unborn animals were harmed when high levels of toluene were inhaled by their mothers, although the same effects were not seen when the mothers were fed large quantities of toluene. Note that these results may reflect similar difficulties in humans.
  • Data on ethylene glycol mono-n-butyl ether is used to represent all glycol ethers because it is the most commonly used glycol ether in printing.  It can leach into ground water, and reacts with photochemically produced hydroxyl radicals.  For humans, moderate exposure may cause central nervous system depression, including headaches, drowsiness, weakness, slurred speech, stuttering, staggering, tremors, blurred vision, and personality changes. These symptoms are such that a patient, in the absence of an accurate occupational history, may be treated for schizophrenia or narcolepsy.
  • Methyl ethyl ketone contributes to the formation of air pollutants in the lower atmosphere; breathing “moderate amounts” for short periods of time can cause adverse effects on the nervous system ranging from headaches, dizziness, nausea, and numbness in the fingers and toes to unconsciousness; repeated exposure to moderate to high amounts may cause liver and kidney effects.

Everybody is now talking about “water based” inks, as if that’s the answer to help reduce these emissions.  So, let’s investigate these inks and see what “water based” means, and what the concerns may be.

There are three general types of texile inks (or pastes, as we referred to them in Printing – Part 2):

  • traditional solvent-based inks
  • water-based inks
  •  plastisol inks

The two inks used most often in textile printing are water-based (used mostly for yardgoods) and plastisol  inks (used for printing finished goods, such as T shirts, sweatshirts, tote bags).

SOLVENT-BASED INKS:   The solvent has two primary functions: 1) to carry the ink to the substrate, and 2) to evaporate quickly, leaving only the ink film on the substrate. While water is a solvent, the name solvent-based ink is used to describe a highly volatile solvent such as 2-butoxyethyl acetate, cyclohexanone and n-butyl acetate.

Solvent based inks are considered the least environmentally friendly due to the  highly volatile solvents given off during printing and drying. The petroleum-based binder used in many solvent-based inks could be replaced with renewable resources such as vegetable oil or soy. The downsides are that the inks dry very slowly are less durable, and still contain solvents emitting VOCs during printing.

Therre are now inks on the market called Eco Solvent inks.  To most people, “eco” means ecological, and to be fair these inks are not as nasty as full solvent inks.   But these inks generally contain glycol esters or glycol ether esters – both derived from mineral oil – hardly a renewable resource or an ecologically sound process.  Tony Martin, president of Lyson Inc. suggested we call these inks “mild” vs. the “aggressive” traditional solvent inks.  Also since these inks are generally used to print onto PVC, the green claim sorta gets overlooked by the elephant in the substrate.

WATER-BASED INKS:  These use water as the main solvent.  But that does not mean that water is the ONLY solvent used.  It is significant to note that many water base inks contain “co-solvents” which may even be petroleum based solvents.[4] ( See Printing – Part 2 for components of typical water and solvent based inks.) The reason these co-solvents are used varies, but a main reason is to decrease the time and heat necessary to cure the ink on the fabric.

There are two types of water-based inks: Traditional (air dry) ink and Discharge ink.

  • Traditional air dry ink soaks into the cloth and binds with the fibers providing good colorfastness and wash ability.
  • Discharge ink removes the original dye/color from the garment and replaces it with a color/pigment. Discharge inks are now available in formaldehyde free formulations, such as the Oasis Series by Wilflex, making them safer for the user and the environment.

Water based inks are usually less expensive than solvent-based inks and are similar in quality, gloss, and adhesion.

Many printers observe that water-based inks have more vibrant colors and print more crisply than their solvent-based counterparts. The sharper definition possible with water-based inks allows printers to use finer dot patterns in screened process printing. Water-based inks are a good choice when a “soft hand” is desirable. (A soft hand is the condition where the ink film cannot easily be felt with the hand when passed across the surface of the fabric. This affect is often used as an argument for why water-based is preferable to plastisol  because plastisol has more of a hand than water-based, and this is considered a consumer turn off.)

These inks are inexpensive and easy to manufacture. In fact, with some experience and the proper equipment, printers can even make them in small batches from basic natural components. They have a very limited shelf life and are difficult to re-use, so they generate more wasted ink than regular plastisols or more complex, manufactured water-based inks. While this type of water-based ink is considered a very green alternative, this extra waste is something to consider.

An advantage often cited for water-based inks is that they do not require organic solvents when cleaning the presses.  But there is a common misconception that because water can be used for cleaning screens, squeegees and tools, that the waste water can just be discharged into the sewer. However, the water-based ink is not just water. There are pigments, binders, thickeners, and sometimes, even co-solvents in the ink residue.

Many printers believe that screen printing using water based inks is the cutting edge of textile printing.  So why isn’t everybody using them?

Water-based inks cure as water evaporates out of the ink so they have a longer – and more difficult –  drying time than plastisol inks. This means that the water — along with whatever in the ink evaporates with the water — enters the environment.

If using water-based ink, the facility must have the drying capacity to remove the water. The dryers used for water-based printing tend to be larger than those needed for plastisol.  In plastisol printing, the ink film must only reach the cure temperature for a brief moment. With water-based ink, the temperature must be reached and then held until all of the solvent (water) is removed. There are water-based inks that will air dry but they are usually only acceptable for craft level printing as the room required for curing greatly reduces productivity.
Finally, all water-based inks can start to dry out during use, so care must be taken to prevent the ink from drying on the screen.  If water based ink is left in open mesh for even a short period of time, it can clog the mesh and ruin the screen. Practiced waterbased ink printers must always be conscious of how long a screen sits between prints to prevent the ink from “drying in”. While modern water-based inks are less prone to this phenomenon, it is still a concern.  In addition, overall shelf life is limited.

There have been major improvements in manufactured water-based inks in recent years. These newer inks have a number of performance advantages over the basic water-based inks discussed above and are as potentially eco-friendly and sustainable as any alternative. For example, they resist drying, and remain useable far longer than traditional water-based and discharge inks. They can be re-constituted with water — and additional binder, if needed — which can cut back on waste. Shelf life of these newer water-based inks is substantially longer as well because the manufacturers have developed technology to encapsulate the water in the ink in such a way that it does not readily evaporate until printed.

Much like traditional plastisol, these water-based inks are sold ready to use as colors or underbases and have a thicker viscosity that yields greater opacity on finished prints. They can be reduced with water and other modifiers for a softer hand.

PLASTISOL INKS:  Plastisol inks, commonly used for textile printing and especially for t-shirts, are a PVC-based ink composed of a clear, thick plasticizer fluid and PVC resin. The full name for PVC is polyvinyl chloride. The PVC life cycle results in the release of toxic, chlorine-based chemicals which end up as by-products such as carcinogenic and highly toxic dioxin and PCB.  The major health concern about plastisol inks is not that they are PVC-based but that they contain phthalates. Phthalates are added to PVC plastics to transform a hard plastic into a soft, rubbery plastic by allowing the long polyvinyl molecules to slide against each other instead of rigidly binding together. These phthalates used in plastisol ink to make the PVC flexible are also carcinogenic and much research has been done which substantiates the damage phthalates do to us,  especially to fetuses and newborns.[5] They are released into the environment during the printing and curing of the ink and they will continue to exhaust toxins when exposed to a radiant heat source, such as a dryer or even sunlight.  Plastisol inks contains virually no solvents at all.

Plastisol does not “dry”. In order for a compound to dry, there must be evaporation of some kind of solvent.  These inks typically contain less than 1% VOC.  Some water based plastisol inks can contain about 30% VOCs.[6] Since plastisol has little or no solvent, it cannot dry. Plastisol is a thermoplastic ink  – meaning it is necessary to heat the printed ink film to a temperature high enough to cause the molecules of PVC resin and plasticizer to cross-link (i.e., bond to the fabric)  and solidify, or cure.  Cross-linking agents must be used to effect the bonding, and  formaldehyde is often a necessary component of these cross linkers.  The temperature at which most plastisol for textile printing cures at is in the range of 300 °F to 330 °F.  Because of this characteristic, plastisol can be left in screens for long periods of time without clogging the mesh, the lids can be left off of the ink containers (although keeping them covered is a good practice to keep lint and dirt out of the ink). And ink left at the end of the job can be returned to the container for reuse without any adverse affects. This last practice is a great benefit in reducing waste product.  It is ready to use right out of the container more than 90% of the time. In most applications, it can be printed wet-on-wet, which allows for increased production speeds. It comes in formulations that can be printed on light and dark fabrics.

Since Plastisol is a thermoplastic, it will remelt if it comes in contact with anything hot enough. For that reason, plastisol prints cannot be ironed. If an iron touches a print, it will smear the ink.

Plastisol ink also creates an ink film that can be felt with the hand. The higher the opacity of the ink, the greater the hand. This heavy hand is considered a disadvantage at the consumer level.

Because both PVC and phthalates are chemicals of concern, many companies are offering phthalate free plastisol inks. These non-phthalate inks are not as easy to work with as standard plastisols, but it is possible to use them to accomplish most of the common printing techniques. In addition to non-phthalate plastisols, there are some new acrylic-based screen printing inks that are sometimes referred to as non-PVC and non-phthalate plastisols. Why? Well, an acrylic-type resin replaces the PVC resins used in regular plastisol. Also, the plasticizer in acrylic inks is normally non–phthalate, making these inks an even more eco-friendly alternative.

With some experience, acrylic inks can be successfully made into high-density designs. The finished prints lack the soft finish of a standard high-density plastisol print, but this may be an acceptable compromise to some customers.

Acrylic inks are usually a little more costly than standard plastisols and are substantially more expensive than standard water-based inks.

The hazards of plastisol printing inks are not just to personal health but also to environmental health. Garments coated with plastisol inks do not decompose and they are difficult to recycle. The result is that you may soon grow tired of your Rolling Stones concert tee shirt and trash it, but it will live on in immortality in the local landfill. If clothing designed with PVC plastisol ink is incinerated, the trapped dioxins plus hydrochloric acid (a primary component of acid rain) are released into the atmosphere.

New inks have also been developed for digital printing, such as latex, resin and UV curable inks.  We’ll discuss them next week with digital printing.

Dr. Nicholas Hellmuth, of FLAAR (http://www.wide-format-printers.org/), writing in his January, 2011 blog, said of the proliferation of green claims by ink manufacturers: ” I would bet that 90% of these claims were misleading at best. I would bet that more than 50% of these claims are fraudulent and inaccurate… I looked at the MSDS of inks called water-based and almost gagged when I saw the chemical recipe, with the hazardous warnings.  If you make a list of the nasty chemicals that are   really in the ink, depending on what chemicals you consider unhealthy,   resin ink could potentially be considered less unhealthy than even   traditional water-based ink. In other words, there is a potential that   resin inks could be considered better than water-based inks. But there   are so many diverging opinions that I will be discussing this with other   ink chemists as I meet them during the expos early in this year (2011). ”

So you’d think that the major source of the emissions comes from using these inks – the printing process itself.  You’d be wrong:  the majority of emissions to the atmosphere from textile printing is from  the drying process, which drives off volatile compounds.  The largest VOC emission source is the drying and curing oven stack, which vents evaporated solvents to the atmosphere.  Another source of fugitive VOC emissions comes from the “back grey” (fabric backing material that absorbs excess print paste), which  is dried before being washed. In processes where the back grey is washed before drying, most of the fugitive VOC emissions from the back grey will be discharged into the waste water. In some roller printing processes, steam cans for drying printed fabric are enclosed, and drying process emissions are vented directly to the atmosphere.

As of the publication date of the EPA Sector notebook on the Printing and Publishing Industry (1995),  there was no add-on emission control technology for organic solvents used in the textile printing.

Another environmental hazards  in printing textiles comes in the screen and equipment cleaning steps – which use lots of water.  When you finish a printing run, for example, there are still approximately 1.5 gallons of printing paste in the system, predominantly in the tubes that run between the paste reservoirs and the screens. This  is simply rinsed out and flushed down the drain. If using plastisol inks, in order to emulsify the ink for easy removal from screens, squeegees, flood bars, spatulas, and work surfaces, it is necessary to use some type of solvent.   Solvents used to clean printing equipment include toluene, xylene, methanol, and methyl ethyl ketone (MEK). In addition, blankets used to transfer the ink-filled image to sheets of paper are cleaned with washes that contain glycol ethers and 1,1,1-trichloroethane (TCA). The type of solvent used depends largely on the equipment to be cleaned. For example, a blanket wash must dissolve ink quickly and dry rapidly with minimal wiping. Conversely, a solvent that is intended to clean a chain of ink rollers must evaporate slowly, to insure that it does not flash off before it has worked its way through all the rollers. Water based inks contain co-solvents, additives, dyes and/or pigments, which make the water clean up full of possibly hazardous materials.   All of these components must be washed thoroughly.

Irrespective of the type of inks used, all printers attempt to reclaim screens, which are a major cost item. Failure to reclaim screens and ruined screens cost on average $5,000-$10,000 per year. One study showed chemical reclamation cost between  $2 and $10  per average screen, while screen disposal cost just shy of $50. Screen reclamation is a particular challenge to screen printers, because inks and solvents cannot go down the drain and some of the chemicals used to reclaim mesh are restricted.   The waste water will contain particulates comprised of ink pigment, emulsion and emulsion remover.  Reclaiming screens involves these steps:

  1. Remove the paste:  Any and all excess paste in the screen should be “carded off” for reused on another job. The screen must then be washed to remove any remaining paste because the paste will interfere with the process of removing the stencil. Screen cleaning solvents are a source of VOC emissions.
  2.  Emulsion removal:  The stencil or emulsion is removed by spraying the screen with a solution of water and emulsion remover chemicals which is comprised mainly of sodium metaperiodate,  then rinsing the solution away with fresh water.
  3.  Haze or ghost image removal:  Finally, if any haze or “ghost image” remains, a haze remover must be applied. Some haze remover products are caustic and can damage or weaken the screen. Haze removers make screens brittle and tear easily, therefore only small amounts should be used. Ghost image is a shadow of the original image that remains on the screen caused by paste or stencil caught in the threads of the screen.

The best way to reduce VOCs during screen reclamaition are related to technology and best practices, such as using high pressure wash systems and modifying how chemicals are applied to the screens.

The waste ink and the solvent must be disposed of properly in order to minimize environmental impact.  There are three major areas of concern for this wastewater:

  • Heavy metals, which can be found in the residue of ink, can enter the sewer system and contaminate sewage sludge
  • Heavy concentrations of certain chemicals can disrupt the pH balance at the treatment plant and disrupt the bacterial systems essential to the sewage treatment process
  • Combinations of mixtures with low flash points can cause flammability concerns in the sewage system

Leftover print pastes cannot be allowed to enter the wastewater treatment system. It must be disposed of as a solid waste. Sites where sludge piles are used can have environmental problems with ground and groundwater contamination. These sludge storage areas should be equipped with waterproof linings to prevent this from occurring.

In fact, textile printing is becoming an important wastewater source as the water-based materials replace the organic solvents. The wastewaters originating from this operation are often strong and may contain toxics, although their volume is still quite low.[7]

The screen printing industry has been very proactive in the creation of products that can minimize the impact of these cleaning processes. Solvents are available that are “more” environmentally sensitive than the traditional petroleum based solventsCompanies are beginning to market biochemical cleaning solutions, inks and additives to replace current solvents or toxic chemicals– examples include the use of terpene d-limonene (derived from citrus fruit), coconut oil , soybeans, seaweed  and fatty amides. (8)  In addition, there are many types of filtration and cleaning systems available to capture inks and solvent residues to minimize the solids that are discharged into the sewer system.

Aside from improvements to the building itself and efforts to minimize water use and to use inks and paste effectively, there are some things every printer can do to reduce their environmental impact:

  • Minimize downtime on the press
  • Make rejects history
  • Maintain dryers – is it really worth saving money by buying that second hand dryer?  A new one is 30% more efficient, twice the price but the energy savings will pay the difference in 9 months.  An average printing line has a nominal power rating of 75 kW, most of which is required for the drying process.

[2] http://www.epa.gov/ttnchie1/ap42/ch04/final/c4s11.pdf

(3)  Sellappa, Sudha, et al; Genotoxic  Effects in Textile Printing Dye Exposed Workers by Micronucleus Assay, Asian Pacific Journal of Cancer Prevention, Vol 11, 2010;  pgs. 919-922,  http://www.apocp.org/cancer_download/Volume11_No4/c%20919-22%20Sellappa.pdf

[7] Kabdasli, M Gurel & Tunay, O., “Characterization and Treatment of Textile Printing Wastewaters”, Environmental Technology, Vol 21, Issue 10, 2000, pp. 114 – 1155

(8) http://www.pneac.org/sheets/all/biochemicals_for_the_printing_industry.pdf