What are PFAS?

1. What are PFAS?

PFAS stands for Per- and PolyFluoroAlkyl Substances, defined as fluorine compounds containing at least one fully fluorinated methyl or methylene carbon atom (without any hydrogen, chlorine, bromine or iodine attached).^*1 They include a huge number of chemical substances, with 4,730 listed by the OECD and 14,735 by the USA EPA.^*1,2 While varying in character, PFAS find very wide use in home and industry applications due to their outstanding chemical resistance, heat resistance, water repellency, insulation properties, and other attributes.

*1: Reconciling Terminology of the Universe of Per- and Polyfluorfluoroalkyl Substances (OECD)

*2: Navigation Panel to PFAS Structure Lists (EPA)

2. PFAS regulations

Concerns over the effect of some types of PFAS on the environment and human health have resulted in continuously evolving regulatory trends. Regulatory frameworks are being discussed and established by the United Nations and in Europe, some states in the United States, and other countries worldwide. Two major activities in this area are: (1) the United Nations Stockholm Treaty (Persistent Organic Pollutants: POPs), and (2) EU trends.

(1) United Nations Stockholm Treaty (POPs)

• Of the 10,000+ PFAS known to exist, the signatories to the treaty have regulated the production and use of PFOS, PFOA, and PFHxS types in their countries due to the high resistance to degradation, tendency to accumulate, and toxicity of these substances.^*3​
• In Japan, it is designated as a Type 1 specified chemical substance under the Chemical Substances Control Law.
• The Environmental Protection Agency (EPA) defines nine PFAS, including these 3 types, as “Specified PFAS^*4。
• Regulation of long-chain perfluoro carboxylic acids (LC-PFCA) is also under consideration.^*3。
• Fluorocarbon polymers and fluorine rubbers such as PTFE and PFA, which are widely used in society, are not subject to the POPs regulations.

*3: POPs Convention (Ministry of Economy, Trade and Industry)

*4:EPA – Listing of Specific PFAS as Hazardous Constituents (IHMM)

(2) EU trends

• The European Chemicals Agency (ECHA) is currently considering proposals to restrict the use of PFAS.
• These proposals are based on the important concept of taking protective measures while the risk and severity of PFAS remain unclear. Restrictions are therefore being established even for applications for which no substitutes are currently available.
• At present (January 2024), it is anticipated that the EU parliament could deliberate and adopt PFAS regulations before the end of 2025 at the earliest. The restrictions would then enter into force after an 18-month transition period, and there will subsequently be a 5- or 12-year grace period to develop alternative solutions for applications with no available substitute (please see Note^*5 for details about these applications).
• It is possible that polymers considered non-hazardous at present will also fall within the scope of the restrictions, so developments in this area are being closely monitored.
• ECHA invited public consultation in 2023 and expects discussions to proceed based on a summary of all stakeholder opinions. (As developments regarding this regulation are ongoing, the situation may change.)

*5: ANNEX XV RESTRICTION REPORT (ECHA)

3. PFAS substitutes

The PFAS (most PFAS other than “Specified PFAS”) currently used for a variety of applications supporting our day-to-day lifestyle exhibit many outstanding attributes such as heat resistance, chemical resistance, sliding properties, and electric properties. Substitutes with exactly the same performance as these PFAS are almost non-existent, and potential candidates must match the applications and reasons for using PFAS when being considered. For example, it is possible to use resins such as polyoxymethylene (POM) for applications where good sliding properties are critical, but these would need to be considered on a product-by-product basis due to their inferior heat resistance. PFAS are also sometimes used almost unnoticed as additives to enhance sliding properties and flame retardance. In such cases, it is necessary to select PFAS-free materials that exhibit similar properties.

(Written by Isao Sato, Isao Sato Technical Office)

We welcome your inquiries about PFAS substitutes.

Asahi Kasei offers PFAS-free engineering plastics to match your application and objectives.
Please contact us to ask any questions, discuss any concerns, and request samples.

→ Click here for details on Asahi Kasei 's polyamide resin "LEONA™ PFAS-free sliding grade (under development)"