Advancing Adhesives: Non-Toxic Solvents
Can "green" solvents be on a par with their conventional toxic counterparts?
The average person comes into contact with solvents—toxic substances that dissolve other substances—thousands of times each day without even thinking about them. Solvents are in many everyday products: printer ink, shoe polish, cleaning products, nail polish, moisturizers, and cosmetics, among others. For many millions of people—an estimated 10 million workers in the U.S. alone—those daily interactions with toxic solvents can be much more frequent and intense. If you’re working with the substances, then your proximity and their effects can either be immediate (e.g., dizzy spells, nausea and vomiting), or they can be long-term, less easy to spot, and potentially devastating. Because the effects can accumulate over many years, studies regarding the consequences of solvent exposure are often inconclusive; the symptoms can also be attributed to other conditions, some naturally occurring.
In 1998, the Harvard School of Public Health presented a report on a painter who had been exposed to mixed solvents over decades and had been diagnosed with chronic toxic encephalopathy. The findings were significant because the symptoms presented themselves in the patient from the age of 40; subsequent tests showed that he was indeed suffering from a number of ailments that, when combined (along with his young age), signified damage from solvents. However, taken on their own and perhaps in an older patient, the symptoms could have been attributed to other conditions.
Scientists and doctors have studied the effects of long-term exposure to solvents like toluene, xylene, and methyl ethyl ketone (MEK) on humans and the environment for decades. The U.S. Department of Labor warns that daily exposure to these solvents can damage the nervous system, liver, kidneys, and reproductive system, and cause respiratory impairment, cancer, and dermatitis. Canadian labor ministries place limits on exposure to solvents like MEK, toluene and xylene.
Volatile organic compounds (VOCs) are a prime ingredient in the production of smog in urban environments. To combat these serious environmental and health risks, regulators such as the U.S. Environmental Protection Agency (EPA) and state and local environmental departments have set increasingly tough restrictions in the permissible level and content of VOCs in everyday products.
If conventional solvents make people ill and harm the environment, why are they frequently used in consumer and industrial products—especially at a time when people are more health and environmentally conscious than ever? According to David Pasin, co-founder and president of TBF Environmental Technology, the answer is simple: they’re cheap and they work.
“They’re relatively inexpensive and historically that’s what the industry has used,” he said. “But the bottom line is that people don’t want to become sick from their environment. Whether it’s the carpet in their homes or the paint in their offices, people want to know that they’re in a healthy environment and that they won’t develop an illness from it—whether it’s as small as an allergy or as big as cancer.”
New “green” solvents have been developed that reportedly work as well as toxic solvents.* Previous incarnations of environmentally aware products were traditionally not as effective, so there was little incentive for industry-wide change. The new range of products is biodegradable, benzene-free, and non-carcinogenic, and does not contain dangerous air pollutants, environmentally hazardous ingredients, or ozone-depleting chemicals. VOCs readily evaporate into the atmosphere and contribute to a reduction in air quality and an increase in smog. The “green” solvents are considered “zero-VOC” in the U.S. (including most of California) and ultralow-VOC solvents in the South Coast Air Quality Management District (SCAQMD—Los Angeles Air Quality District). Last year, one of the new solvents** received certification as a Clean Air Solvent from SCAQMD, an organization known for its tough stance on toxic and smog-producing substances.
Three different “green” solvents† are available as alternatives to a number of different solvents, such as MEK, which is commonly found in lacquers, varnishes, paint remover, and glues, and is used in the manufacturing of gums, resins, coatings, and vinyl films. Additional solvents that can be replaced by these “green” alternatives include acetone, toluene, xylene, parachlorobenzotrifluoride (PCBTF) and tertiary butyl acetate (TBAc). Toluene and xylene are common solvents in adhesives, paint, paint thinner, printing ink, rubber, and disinfectants. Xylene is also used to remove paraffin wax from tubing in processes such as fracking. PCBTF is used by the printing industry to dissolve inks, and TBAc is found in adhesives, inks, lacquers, enamels, thinners and industrial cleaners. The alternative solvents allow companies to manufacture products that are safer for people and the environment without compromising effectiveness.
“Our solvents are designed to mimic, as closely as possible, the toxic solvents they’re replacing,” Pasin said. “But our products are safer, less polluting, and more marketable because the end user is going to experience better occupational health and safety and air quality by using them.”
Many people are exposed to several toxic solvents at their workplace every day for the duration of their careers. Nail salon workers are exposed to toluene by way of the glue used to apply acrylic nails. According to the Agency for Toxic Substances & Disease Registry, this solvent can cause health effects ranging from dizziness and headaches to memory and vision loss—and even liver and kidney damage. Nail polish remover also contains acetone, which, when ingested in large amounts or over long periods of time, can cause headaches, slurred speech, and even death. The situation is
similar for painters who are exposed to solvents such as toluene and xylene in paint and paint thinners. If aestheticians and painters switched to products with “green” solvents, their workplace health risks would be drastically reduced.
In addition, these alternative solvents could eliminate environmental contamination caused by toxic solvents used in the oil and gas industry. With controversial methods such as hydraulic fracturing, or fracking, often used to extract oil or natural gas from the ground, the use of a nontoxic solvent replacement could not only have a major impact on the health of oil fields and the surrounding environment, but may also ease concerns of environmentalists, nearby residents and future neighbors of drilling sites.
Fracking is a major industry in Canada. A petition†† was submitted to the Auditor General of Canada in June 2011, entitled “Shale Gas Fracking and In Situ Oil Sands Chemicals and the National Pollutant Release Inventory: Public Disclosure Needed.” The petition called for, among other things, disclosure of the toxic solvents that enter the natural environment through the fracking process and the risks associated with them.
While the “green” solvents aren’t considered a clear solution to this controversial issue, they can be seen as an answer to many unanswered questions. “There are reports almost weekly of contamination of water, ground and air in areas where fracking and oil and gas extraction are done because they use
BTEX—benzene, toluene, xylene-type solvents,” said Pasin. “TBF is slowly getting into that market, but mostly our products are being evaluated for use in the oil and gas industry and that’s where we see huge potential for growth.”
All Substitutes are Not Equal
Multiple conventional solvent substitutes are available on the market. D-limonene, for example, is extracted from the rinds of citrus fruit and can be used in industrial-grade and household cleaning products, adhesive removers, hard surface cleaners, and oil field solvents, and as an ingredient in aerosols. It acts as a substitute for MEK, acetone and toluene.
Although D-limonene is non-carcinogenic, non-toxic and does not contain ozone-depleting chemicals, it contains high levels of VOCs, making it unsuitable in any jurisdiction that regulates VOC contents or emissions and must be treated as hazardous waste. “It’s not as toxic in some respects, but it is still considered a VOC,” Pasin said. “It has some pollution effects for air, groundwater and soil.”
The price difference between “green” solvents, conventional solvents and other alternatives like d-Limonene is negligible, according to Pasin. Ultimately, the amount of TBF solvents required depends on the product. The issue for companies contemplating the shift to cleaner, safer solvents isn’t cost: it’s product effectiveness.
“There are a lot of green products out there that don’t work, but they’re green,” said Pasin. “If companies want to stay in business, they have to meet the market demand. And the market is demanding safer products—whether it’s an industrial, commercial or consumer application. And they’re looking for alternatives that work.”
For more details, visit www.tbfenvironmental.com.