STOCKHOLM – The use of potentially toxic chemicals such as PFCs in outdoor clothing is largely unnecessary claims a new study. Researchers compared fluorinated chemicals, which provide water, oil and stain repellency for outdoor clothing, with non-fluorinated alternatives. They found that the best non-fluorinated durable water repellents have water repellency as good as fluorinated polymers – and that water repellency and durability are most important to consumers of outdoor clothing.
First marketed 60 years ago, poly-and perfluoroalkyl substances (PFASs) are used as surfactants, oil- and water-repellent coatings in a range of products including clothing and textiles. But research suggests long-chain PFASs are highly persistent, bio-accumulative and toxic, and many countries are phasing them out. There are also concerns about short-chain PFCs.
While the paper found that non-fluorinated finishes are perfectly fine for outdoor clothing, they do not provide sufficient liquid repellency for medical textiles, and nor do they demonstrate repellency to stains with low surface tensions.
Says the paper: “The best non-fluorinated alternatives demonstrated high water repellency equal to fluorinated side-chain polymers with ‘short’ fluorinated carbon chains ≤6 carbons, and should be considered as suitable substitutes for consumer outdoor clothing. These results are supported by a survey of end-use requirements indicating water repellency and durability were the most important purchasing criteria.
“For polar liquids, with lower surface tensions, the repellency provided by non-fluorinated alternatives was clearly reduced, although they had a moderate repellency towards liquids with intermediate polarity (e.g. red wine or synthetic blood). Only fluorinated side-chain polymers with ‘short’ fluorinated carbon chains ≤6 carbons were seen to provide sufficient protection to polar liquids with very low surface tension (olive oil or gastric fluid).
“Since occupational protective clothing (e.g. medical clothing) often must provide protection against liquid of a wider range of polarities (e.g. in the case of medical clothing, to bodily fluids and protect the wearer from the transmission of diseases), current non-fluorinated DWRs do not provide sufficient liquid repellency. This implies that innovations in textile technology are still needed to substitute PFASs in some types of occupational protective clothing and other end uses where oil and stain repellency is essential.”
Commenting, Stefan Posner, a senior researcher at RISE (Swerea IVF) who has several decades working in this complex area, said: “When there are reasons for continued use of Chemicals of Concern (CoC) or their alternatives , some criteria need to be fulfilled to declare these uses as: essential for health and life protection; when critical for the functioning of society; when no available technically and economically feasible alternatives/substitutes; that are acceptable from the standpoint of environment and health. If one or more of these criteria are not met, the use cannot be considered as essential.”
Many apparel brands have discontinued the use of PFCs in clothing altogether, while outdoor clothing brands are shifting towards short-chain PFCs only or non-fluorinated alternatives.
Full paper here: https://www.sciencedirect.com/science/article/pii/S0959652619301799