Replacement of nonylphenol ethoxylates (NPEO) compounds in textile production processes by alkyl ether ethoxylates (AEO) compounds
Textile production could involve the use of nonylphenol ethoxylates (NPEO) compounds for its surfactant properties. Because of the conceivable aquatic toxic and endocrine disrupting effects of NPEO, a more environmentally benign alternative, alkyl ether ethoxylates (AEO) compounds, is adopted to conduct the degumming process. The shift from NPEO to AEO, while giving intended cleaning effect, was demonstrated to result in only a slight change in process and no perceivable impact to product quality.
The different nonylphenolethoxylates are on the hazardous substance database according to SUBSPORT screening criteria (SDSC) for being endocrine disruptors and some also PBTs. The alternatives have no official classification and are not listed on the SDSC.
Nonylphenol ethoxylates (NPEO) are a class of non-ionic surfactant widely used in industrial cleaning and washing applications. The use of NPEO is restricted in Europe through the REACH Regulation (EC No 1907/2006, No 552/2009 amendment) as regards Annex XVII, where NPEO compounds shall not be placed on the market, or used, as substances or in mixtures, in concentrations equal to or greater than 0.1 % by weight for a number of applications. Among them is textile- and leather processing except when processing with no release into waste water, or on systems with special treatment where the process water is pre-treated to remove the organic fraction completely prior to biological waste water treatment (degreasing of sheepskin). Although NPEO is restricted in Europe because of REACHregulation, its use in other part of the globe is not regulated. Continued use of NPEO compounds has severe drawbacks to both the environment through waste water discharge and potentially to human health as well. The compounds are classified as endocrine disruptor under the SIN list and many fashion brands, including the author’s organization, enclosed NPEO into their RSLs (restricted substance lists). One of the ecological effects could be due to the formation of nonylphenol and short-chain ethoxylated nonylphenols in aquatic environment resulted from microbial degradation of NPEO.
Nonylphenol and short-chain ethoxylated nonylphenols are believed to be persistent, moderately bioaccumulative, and toxic to aquatic organisms. [“Nonylphenol (NP) and Nonylphenol Ethoxylates (NPEs) Action Plan (RIN 2070-ZA09), The U.S. Environmental Protection Agency, 8/18/2010]. Nonylphenol has also been detected in human breast milk, blood, and urine and is associated with reproductive and developmental effects in fish.
NPEO as a non-ionic surfactant are used in a wide variety of applications including detergents, cleaners, degreasers, dry cleaning aids, petroleum dispersants, emulsifiers, wetting agents, adhesives, agrochemicals, including indoor pesticides, cosmetics, paper and textile processing formulations, prewash spotters, metalworking fluids, oilfield chemicals, paints and coatings, and dust control agents. Intended functionality of NPEO is resulted from the chemical structure where the ethoxylate end of the molecule is hydrophilic (“water-attracting”) and the akylphenol end hydrophobic (“water-avoiding”). The hydrophilic “head” attracts water and the hydrophobic “tail” attracts poorly soluble substances, such as oils and greases. This ability to simultaneously attract water and hydrophobic substances makes NPEO useful in the surfactant applications listed above.
The alternative chemical, the alkyl ether ethoxylates (AEO), also a non-ionic surfactant, has the same basic structure with a hydrophilic ethoxylate end and a hydrophobic alkyl ether end. The AEO is not considered hazardous and, when degraded, does not form badly persistent chemicals such as nonylphenol. Once identifying such a possible alternative, a pilot project was run in a Vietnamese factory producing knit T-shirts. While the yarn was produced in Korea and found to be free of NPEO, NPEO was found after the knitting and sewing processes in Vietnam. The most possible source of NPEO was the degumming process. So after reviewing all of the chemical formulations, we have identified the source as the agent used in the degumming process, and we changed the agent from a previously NPEO-based chemical to now an AEO-based formulation. With slight process adjustment, newly produced T-shirts were found to contain no observable level of NPEO as tested in a third party laboratory. It was concluded that the change of degumming formulation was successful in eliminating the use of NPEO with no significant process change required, and with no observable impact on product performance.
Alkyl ether ethoxylate was found a feasible replacement of alkylphenol ethoxylates (such as NPEO). The former was not classified according to Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation) and not recognised as an endocrine disruptor. The intended application in textile production was successful only with a slight process adjustment with no observation effect on subsequent product quality.
This case study describes substitution of a group of substances facing increased restrictions due to their endocrine disruptive properties. The alternative substances are not listed in the SDSC nor have any official classification. The substitution is said not to need any significant changes of process and does not affect the product performance.
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Publication or last update: 18.03.2013