From C8 to C6 and PFC-free

What does this mean? And what solution does A&E Gütermann offer with regard to PFC-free, water-repellent sewing threads?

water-repellent outdoor clothingWhether it comes to fashion, sports, outdoor or technical textiles: With the help of certain finishes, textile products can acquire a number of improved and/or additional properties in the course of the production chain - including sewing threads - such as water-, dirt- and oil-repellent, flame-retardant or antistatic properties. However, not all chemicals used are per se harmful to humans and the environment.

A&E Gütermann sewing threads are manufactured in compliance with the strictest chemical regulations, such as the REACH candidate list, and are therefore harmless during processing. Nevertheless, PFC-containing substances are frequently used for the functionalization of textiles today - but their use is increasingly controversial or even prohibited due to their environmentally and health damaging properties.

I. From C8 and C6 fluorocarbon resins to PFC-free chemicals

The abbreviation ‘PFC’ stands for perfluorinated and polyfluorinated chemicals, which have been widely used since the 1950s. They include more than 800 different substances which, due to their special properties (water-, oil- and dirt-repellent, chemically and thermally stable), are used for a variety of different applications, e.g. for textile finishes. PFCs do not occur in nature and are not biodegradable. For this reason, they are currently the subject of strong criticism.  As a result of the EU Chemicals Regulation (REACH) and other laws, as well as a steadily growing consumer interest in sustainable textile products, there are currently a number of demands to replace these PFCs with more sustainable alternatives.

PFOS compoundsPFOA compounds

Notable among PFCs are perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), also known as "C8 PFCs”. The C8 chemistry was used for many years to give textiles water-, dirt- and oil-repellent properties. The areas of application are diverse: whether sports and outdoor clothing, home textiles, workwear or safety equipment. However, due to their persistent, bioaccumulative and toxic properties, the worldwide circulation and use of PFOS have been on the banned list of POPs (persistent organic pollutants) of the Stockholm Convention since 2010 with few exceptions and have since lost relevance for the textile industry. In 2013, PFOA compounds were also identified as a chemical of very high concern and were added to the REACH candidate list. The substance is considered to be toxic for the liver and harmful for reproduction. Its half-life in the blood is about 3.5 years. According to EU Regulation 2017/1000, PFOA and precursor compounds (i.e. substances that can release PFOA) may not be produced or placed on the EU market after 4 July 2020. However, for certain areas of application such as occupational safety textiles or membranes for medical textiles, an extended deadline applies until 2023.

c6 fluorocarbon resinsc6 fluorocarbon resins

C6 fluorocarbon resins are now increasingly being used as an alternative to C8 chemistry. C6 PFCs have two carbon atoms less in their structure, but are otherwise almost identical to C8 fluorocarbon resins. With C6 chemistry, almost comparable results can be achieved with regard to water-, dirt- and oil-repellent finishes, but larger quantities have to be used. The manufacturing process also requires an elaborate cleaning step to comply with the required limited value for PFOA and precursor substances. Consequently, even these short-chain PFCs are not a permanent solution for the finishing of textiles. A restriction or even prohibition procedure similar to those for PFOA is already emerging. Even switching to C4 chemistry will not be sufficient in the long term. Experts therefore expect a complete ban on textile fluorochemicals in the near future.

The aim in future will be to use PFAS-free impregnations, i.e. fluorine-free alternatives. C0 (C-Zero) is also often mentioned in this regard. Eliminating PFCs completely, however, is not quite as easy, since the alternative substances do not have the same performance as PFC-based impregnations, especially in terms of dirt- and oil-repellent properties. For purely water-repellent finishes, however, various substitute products with environmentally friendly properties are available. For example, PFC-free DWR (durable water repellent) finishes, which are currently mainly produced using waxes, paraffins, polyurethanes or dendrimers. Some of the products available on the market are even based on renewable raw materials such as Teflon EcoEliteTM or ecorepel® Bio.

II. Our way to PFC-free, water-repellent sewing threads

Particularly with functional textiles such as rain jackets or outdoor textiles like tarpaulins, tents and sails, it is important that not only the fabric but also the penetration of moisture and dirt through the seams is reduced in order to provide reliable protection. In view of the current PFC debate, the development of a PFC-free WA equipment was therefore not only an incentive for us, but a lived responsibility.

Our PFC-free alternative to WA finishings is called ‘REPEL’. REPEL is a water- and dirt-repellent finish for sewing threads, which is applied onto the thread using a special UFP process and then joined to the sewing thread under the influence of heat. REPEL is resistant to washing and can be processed easily. In addition, REPEL meets the requirements of both, the blue methylene test and the Gore test.

Its water penetration resistance is also proven, having passed the ‘rain test’ method in accordance with ISO 22958-2005 OR AATCC 61. A finishing with REPEL has no negative effects on the thread colour and is therefore absolutely reliable. The fields of application are highly diverse and range from outdoor applications, activewear and footwear to workwear.

On request, other products can also be finished with REPEL. For further information, please contact us at

What are the benefits of PFC-free, water-repellent sewing threads?

  • Production without any fluorine chemistry
  • No persistent, bioaccumulative or toxic properties
  • Not harmful to the environment or human health
  • Durable, water-repellent function
  • Wash-resistant at temperatures up to approx. 40°C

Processing tips for PFC-free, water-repellent sewing threads

Although the risk of water permeability is minimised by water-repellent sewing threads, the seam of water-repellent functional textiles remains a weak point, especially at the stitch holes. In order to further reduce water permeability in the seam area, the following processing tips may be helpful: