While chlorine and bromine are widely recognized, reported, and restricted as halogens in many applications, it is noteworthy that fluorine, iodine, and astate (other Group 17 / VIIA halogens on the Periodic Table of the Elements) are not listed. restricted in accepted industry definitions. of “halogen-free”. Depending on the industry that considers the designator “halogen-free”, chlorine and bromine are the only halogens restricted and then at levels below 900-1,000 parts per million.
In the case of fluorine used in plastics, many anti-drip agents used in “halogen-free” plastic compounds, including polytetrafluoroethylene (PTFE), better known as Teflon®, contain fluorine and anti-drip agents have been reported to be used in the range 0.1-1.4% by weight. Some of these products may contain significant amounts of fluorine that exceed the generally accepted level under IEC 61249-2-21 as content limits established for other halogens (0.09% or 900 parts per million). In other cases, fluorinated salts can be formulated into plastic products at typical levels of 800 parts per million, especially plastic parts produced from polycarbonate, to impart flame retardant properties while the product is labeled “halogen-free.”
Furthermore, it is noteworthy to note that fluorinated polymeric resins incorporated or alloyed in a plastic composite also do not contribute to the “halogen-free” status of a finished polymer due to the omission of fluorine from the list of halogens considered. Such fluoro resins that could be incorporated or alloyed to impart improved electrical, flammable, and processing properties include:
or polyvinylidene fluoride (PVDF),
or ethylene trifluoroethylene (ETFE)
or copolymers of ethylene and chlorotrifluoroethylene (ECTFE)
or polytetrafluoroethylene (PTFE)
or fluorinated ethylene propylene (FEP)
The apparent omission of fluorine, a halogen used in polymeric additives and plastics that are subsequently combined with other plastics on a regular basis to impart fire resistance and other properties, is primarily due to testing methodology and limitations in the detection of fluorine. The test methods used to detect bromine and chlorine do not have the ability to detect fluorine, and as such, fluorine is not detected or reported, although it is also a halogen. Without meaningful direction in testing methodology, regulators are unlikely to consider total halogen content in the near future; however, environmentalists have become aware of the toxicology of fluorine and possible human effects in recent developments related to contamination of groundwater by fluorinated compounds and the potential effects of thermal decomposition of PTFE.
Recent concerns about the potential toxicological effects of groundwater contamination by some fluorinated precursors and by-products, including perfluorooctanoic acid (PFOA) in the United States, as well as possible human toxicological effects caused by contact with products containing PTFE produced by DuPont, better known as Teflon. ®, could lead to a revision of this apparent dual status of halogen materials used throughout the industry. According to the environmental research organization Environmental Working Group:
“… in the last five years, the multi-billion dollar” perfluorochemicals “(PFC) industry, which underpins world-famous brands such as Teflon®, Stainmaster®, Scotchgard® and Gore-Tex®, has become a priority for scientists and officials of the US Environmental Protection Agency (EPA). The PFC family is characterized by chains of carbon atoms of different lengths, to which the fluorine atoms are tightly bound, producing chemicals essentially indestructible that until recently were thought to be biologically inert. Nobody believes it now. “
Since 2000, the United States Environmental Protection Agency (US EPA) has conducted a significant review of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). [US EPA PFOA Factsheet] In 2000, the US EPA peremptorily forced the removal of PFOS, the chemical used for decades as an active ingredient in 3M’s popular Scotchgard® water and stain repellent. Around the same time, 3M stopped manufacturing the related perfluorochemical PFOA.
Throughout 2005, the United States Environmental Protection Agency has subjected PFOA to intense regulatory scrutiny due to reports of groundwater contamination. PFOA is most widely used in the manufacture of PTFE. A major brand of PTFE under scrutiny is Dupont Teflon®. Due to the findings of toxicity studies and the presence of PFOA in the blood of more than 90 percent of the United States population, the United States Environmental Protection Agency continues its review of human toxicity studies and possible health effects.
In December 2005, Dupont reached a $ 16.5 million settlement agreement with the United States Environmental Protection Agency in an enforcement action related to the chemical compound PFOA; This settlement follows a $ 107 million civil settlement in March 2005 on matters related to the alleged contamination of local drinking water with PFOA by Dupont in West Virginia, USA.
In 2006, many states will consider the issue of the content of PFOA and PFOS in plastics and other materials. In California (USA), a coalition made up of the United Steelworkers (USW), Sierra Club, Environmental Law Foundation, Environment California, US Public Interest Research Group (PIRG), Natural Resources Defense Council (NRDC) and Environmental Working Group ( EWG) filed a petition for PFOA to be listed as “a state-recognized cancer-causing chemical” under the California Safe Drinking Water and Toxic Substances Compliance Act of 1986, commonly known as Proposition 65. Yes adopts, the finding would require information labels on products based on specific toxicological findings under California Right to Information requirements. Additionally, the Senate Environment Committee reviewed a preliminary report on perfluorochemical contamination in Minnesota in February 2006.
In April 2006, sixteen lawsuits filed in a $ 5 billion class action lawsuit were transferred to Federal Court in Des Moines, Iowa, USA. Court documents allege that Teflon® manufacturers withheld information about the chemicals used to make the Teflon® chemicals that are supposed to be released when pans are heated. Dupont, the manufacturer of Teflon® says the material is safe.
With settlements in recent cases, class action pending in Iowa (USA) related to potential human poisoning from glue-free fluoride cooking surfaces, and information that has now been developed and shared during peer review, the Environmental watchdog groups and regulatory officials continue. his reviews and research on the widespread use of perfluorochemicals in many industries without an immediate indication of potential results. It should be noted that the use of perfluorochemicals as anti-drip and flame retardant agents or the use of fluorinated polymers such as PVDF or FEP has not been affected by any of the research up to this point. However, because the use of perfluorochemicals is allowed within the guidelines for “halogen-free” materials, reformulating polymeric materials to eliminate the use of these examined materials provides a significant opportunity from a technological development point of view. by providing truly “no halogens”. materials for the market.
JMME, Inc., Copyright 2006, All Rights Reserved