What are the restrictions on the use of PFOS and PFOA in water and oil repellents?

1. Ban on PFOS and PFOA in the United States and Europe

Around 2001, data provided by the U.S. Environmental Protection Agency (EPA) pointed out that perfluorooctane sulfonyl compounds (PFOS) are highly persistent in the environment and will accumulate in the environment. It accumulates in human and animal tissues, causing potential harm to human health and the environment. Based on environmental governance and human health, the production and use of PFOS was suspended. At that time, the Scotchgard FC series products of 3M Company in the United States were discontinued.

Research from the U.S. Environmental Protection Agency also shows that perfluorooctanoic acid (PFOA) and its salts are also organic polymers that are difficult to biodegrade and are highly persistent in the environment. They also accumulate in the environment and accumulate in human and animal tissues. , if it enters the food chain, it will also cause potential dangers to human health and the environment. In fact, there is still considerable uncertainty about the potential harm of PFOA and its salts to the human body, and how PFOA is transferred into the environment and causes harm to human health has not been confirmed. EPA believes that when certain organic chemicals that may release PFOA are manufactured and processed, their ban or restriction requires more scientific information to conduct a risk assessment. Currently, the U.S. EPA has proposed a PFOA Stewardship plan

(PFOA voluntary reduction plan) 100% reduction in 2015, that is, zero emissions. As countries conduct in-depth research on the toxicology and ecology of PFOS, the Organization for Economic Cooperation and Development (OECD) issued a PFOS risk assessment report in 2002. PFOS is classified as a toxic substance that is difficult to decompose and can accumulate in the body. Chemicals (Persistent in the environment bio—accumulative and toxic tomammalian species. PBT substances for short). According to the risk assessment results of the OECD, once PFOS is ingested by an organism, it will be distributed in the blood and liver. Due to its strong stability, it is likely to be difficult to be broken down through the metabolism of the organism. PFOS can be excreted from the body through urine and feces, but it is very slow, and the “half-exclusion time” in different species varies greatly. It only takes 7.5 days for mice, while it takes 8.7 years for humans. PFOS has a variety of toxicities, which can not only cause damage to the human respiratory system, but also cause the death of newborn babies. Animal experiments have proven that PFOS containing 2 mg/kg in the body can cause death. The Scientific Committee on Health and Environmental Risks (SCHER) conducted a scientific review of the above assessment and confirmed on March 18, 2005 that PFOS is a particularly persistent, bioaccumulative and toxic chemical.

In view of this, the European Parliament announced the 2006/122/ECOF directive restricting PFOS on December 12, 2006, reaffirming the limit regulations on PFOS passed by the European Parliament on October 25, 2006:

(1) If its content reaches or exceeds 0.005% (50 mg/kg), it shall not be used for raw materials

Raw materials and preparation components;

(2) The limit of semi-finished products is 0.1% (1 000 mg/kg);

(3) The limit for fabrics and other PU coating materials is 1 m.

The decree stipulates that all member states must incorporate the above provisions into their laws before December 27, 2007, and will be officially implemented on June 27, 2008. The decree suspects that perfluorooctanoic acid (PFOA) and its salts pose similar risks to PFOS, but does not propose specific limits and implementation dates. However, many sellers of fabrics and workwear currently require that PFOA and its salt content cannot be detected.

The current production process of fluorine-containing water-blocking, oil-repellent, and easy-to-decontaminate finishing agents uses perfluorooctane, so this type of finishing agent inevitably contains trace amounts of PFOS and PFOA. The TEXCOTE series of new water- and oil-blocking agents launched by Swedish Nanotech are completely free of PFOS and PFOA.

2. Other chemicals containing PFOS and PFOA

In addition to water-repellent, oil-repellent, easy-to-remove finishing agents, chemicals containing PFOS and PFOA also have certain surfactants and additives. ?Fluorooctane sulfonamide surfactants are divided into anionic, cationic, nonionic and amphoteric types. Cationic PFOS surfactants can be used as inks, coating additives, corrosion inhibitors, fluxes, floor wax additives and fiber additives, etc. They can also be used as bactericides, dispersants and light water foam fire extinguishing agents.

3. Detection of PFOS and PFOA

Currently, the content detection of PFOS and PFOA is carried out by HPLC/MS after solvent extraction. The EU stipulates that the PFOS content in finished chemical products shall not exceed 0.005%; H&M stipulates that PFOS and PFOA in fabrics, leather and plastic products should not be detected. Adopting HPLS/MS can meet the needs of trace detection

Require.

4. Alternatives to PFOSand PFOA

(1) After the U.S. EPA proposed a ban on the use of PFOS in 2001, 3M announced in 2002 that it would no longer produce PFOS-related products, and at the same time developed perfluorobutyl sulfonyl compound (PFBS) as a PFOS substitute. However, if it is effective as a paint additive, metal etching agent, etc., it can be used in fabrics.Water and oil repellent are not effective. Because the full **** oil repellency below C cannot reach 130, the critical surface tension cannot reach below 10 mN/m.

(2) The principle of water- and oil-repellent finishing using nanomaterials (such as zinc oxide) is based on the self-cleaning effect of lotus leaves. On the rough surface of the lotus leaf, the water droplets only come into contact with some of the wax crystal hairs on the surface of the lotus leaf, which significantly reduces the contact area between the water droplets and the solid surface, expands the interface between the water droplets and the air, and the water passes through By expanding its surface area and obtaining a certain amount of energy, the droplets will not automatically expand and remain spherical.

(3) Perfluorohexanoic acid with a certain degree of polymerization is used to form a film on the surface of the fabric, which has water-blocking and oil-repellent properties.

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