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More environmentally friendly alternatives to PFOS-compounds and PFOA

4 Use of PFOS-related compounds, PFOA, and their alternatives

It could be assumed that all the focus on the environmental problems of PFOS and PFOA would result in a shift away from using these products. However, this is not necessarily the case – at least not for all uses and at least not yet. A comprehensive survey of the world production of PFOS-related substances does not exist, for which reason it is difficult to say exactly if the use of these substances is beginning to decrease.

Even though the 3M Company started to phase out the production of PFOS chemicals and PFOA in the year 2000 and today has replaced the C8 chemical perfluorooctane sulfonate (PFOS) with a C4-chemical (PFBS – perfluorobutane sulfonate), the production of these substances has not necessarily fallen drastically. After the 3M Company has ceased their production of PFOA, DuPont has initiated a production of PFOA for internal use (though in smaller scale than the former manufacture by 3M). It is likely that other companies also have continued the production of PFOS and PFOA. Nevertheless, fact is that the 3M Company has stopped the production of PFOS-related compounds and now focuses on the production of C4- compounds. Dyneon/3M, DuPont, Miteni, Ashai Glass and Daikin produce PFOA principally for use in fluoropolymer processing (Personal communication DuPont 2004a).

A quick search in the database of the United States Patent and Trademark Office (www.uspto.gov) shows that patents are still granted today with the use of PFOS and PFOA. A search (in May 2004) on "perfluorooctane sulfonate" resulted in 190 patents, where the most recent patent, which concerns photo-acid generators, is dated 25 May 2004. Actually, 21 of the 190 patents mentioning "perfluorooctanesulfonate" have been issued in 2004.

Likewise, a search in the same database on "perfluorooctanoic acid" resulted in 358 patents, where the most recent patent, which concerns applications for perfluorovinyl ethers, is dated 18 May 2004. This specific patent describes that perfluorooctanoic acid is a more effective processing aid for the production of the mentioned fluoropolymers. In all, 11 of the 358 patents mentioning "perfluorooctanoic acid" have been issued in 2004.

A hit on the words "perfluorooctane sulfonate" and "perfluorooctanoic acid" in the patent database does not necessarily mean that the issued patent utilise PFOS or PFOA for production or similar. However, it is striking that both PFOS and PFOA are mentioned in so many new patents.

The following pages describe the properties and general uses of PFOS-compounds and PFOA, as well as known alternatives to PFOS-related compounds and PFOA.

The primary purpose of this project was to collect know-how about the technical alternatives to PFOS-related compounds and to PFOA. The method used in identifying alternative compounds is described briefly in chapter 2. In short, a combination of contacting producers, search in literature, and search on the Internet for information on alternatives has been used (see Appendix B for details).

In general, telomer-based products are the most common alternatives to PFOS-related compounds. Other compounds that have been identified as alternatives to PFOS-related compounds are presented in details in Appendix F.

The alternative compounds identified in this project are presented in more details in the following paragraphs for the specific use categories. Other alternatives found in literature and other surveys on PFOS-related compounds are mentioned and discussed as well.

4.1 Use of PFOA and PFOA-related compounds

As described earlier, PFOA is primarily used as its salts (primarily the ammonium and sodium salts) as non-reactive processing aids in the production of fluoropolymers and fluoroelastomers and in other surfactant use. Normally, PFOA is not, as PFOS, a part of the products but can be formed through the transformation or metabolism of other perfluorochemicals (like e.g. telomer alcohols) or can be released from the products under use (ENVIRON 2004).

A search in the Danish Product Register for use of PFOA and the PFOA-salts (mentioned in Table 3.4) was performed in this project (see detailed description in appendix D). The search showed that only the PFOA ammonium salt was found in products reported to the Danish Product Register. The PFOA ammonium salt is found in fluoroplastic coatings – a primer and a topcoat. It is present in the maximum concentration of 0.2% and the total amount of the PFOA ammonium salt in products found in the Danish Product Register is maximum 35 kg per year.

No alternatives to PFOA have been identified. Several producers of PFOA were asked about alternative options to PFOA, and those who replied had no alternative options to PFOA.

DuPont has for the last 30 years investigated possible alternatives to PFOA as processing aid in the production of fluoropolymers. Several fluorohydrocarbons have been tested, but the results showed that the presence of hydrogen in the surfactant resulted in problems with the polymerisation. Supercritical carbon dioxide as reaction medium has also been tested in a pilot-scale facility. However, DuPont does not have the expectation that this process will ever evolve into a technology that would have the capability to totally replace the current water-based polymerisation process (Personal communication DuPont 2004a).

The conclusion so far is that DuPont by alternative methods is able to produce only one type fluoropolymer and in limited quantitites, but it does not appear to be feasible to make all products by this route. The conclusion from testing over the last 30 years is that there are no viable alternatives to PFOA (Personal communication DuPont 2004a).

Therefore, PFOA is not discussed in details, as the primary application is as a non-reactive processing aid to produce other fluorinated and perfluorinated compounds. Instead the focus in this chapter will be on PFOS and PFOS-related compounds.

4.2 Use of PFOS and PFOS-related compounds

The majority of PFOS-related chemicals are high molecular weight polymers in which perfluorooctane sulfonate represents a fraction of the total molecular weight (OECD 2002).

Perfluorinated compounds with long carbon chains, like e.g. PFOS, have the ability to repel both water and oil. Because of these special surface-active properties, the PFOS-related compounds are used as surface-active compounds in a range of applications (Kissa 2001; Kemikalieinspektionen 2004). In addition, the PFOS has a unique thermal stability and is stable to acids, bases, oxidants and reductants as well (Moody et al. 2004; Kissa 2001).

Only very few countries have mapped the use of PFOS and PFOS-related chemicals. According to an inventory of the use of PFOS-related chemicals in the United Kingdom, the use of PFAS-related [3] chemicals for carpet and textile treatment was clearly the largest area, representing about 49% of the total use of PFAS-related compounds in the UK in 2001 (see Table 4.1). This also matches the fact that 48% of the production of PFOS-related chemicals produced by 3M in the year 2000 was used for surface treatment purposes (Kemikalieinspektionen 2004; RPA 2004; Hekster et al. 2002).

Otherwise, paper and paperboard treatment and fire-fighting chemicals represent relatively large single uses of PFAS-related chemicals - 15% and 16% respectively in the UK in 2001. The remaining use (20% in the UK in 2001) of PFAS-related chemicals is represented by speciality surfactants and chemical intermediates.

Table 4.1: Application areas for PFAS-related chemicals in the United Kingdom (2001), compared with the former global 3M production of PFOS-related chemicals (2000) (Hekster et al. 2002; OECD 2002; Kemikalieinspektionen 2004; RPA 2004).

Application area Use of PFAS in UK, 2001 (in percent) Application area Former global 3M production of PFOS, 2000 (in percent)
Carpet & textile treatment 48.8 Surface treatment 48
Paper & board treatment 15.0 Paper protection 33
Speciality surfactants 17.5 Performance chemicals 15
Fire-fighting chemicals 16.3 Fire-fighting foams 3
Chemical intermediates 2.5    

As shown above, the PFOS-related chemicals are used in a variety of products within three main categories (OECD 2002):

  • Surface treatment (impregnation) of leather and textiles.
  • Paper protection (impregnation of paper and board).
  • Performance chemicals.

The category performance chemicals can be divided further into more specific use areas, which are described in more details below:

  • Cleaning agents, waxes and floor polishes – industrial and consumer products.
  • Paint and varnish.
  • Pesticides and insecticides.
  • Fire-fighting foams.
  • Photographic industry.
  • Manufacturing of semiconductors
  • Hydraulic oils within the airplane industry.
  • Metal surface treatment.
  • Plumbing – fluxing agents.
  • Other uses.

4.2.1 Impregnation of textiles, leather and carpets

Fluorinated chemicals are extensively used by the textile industry and by private consumers to form a coating on textiles, leather and carpets, which will repel both water and oil. The products used are polymers based on fluorinated acrylates and methacrylates. Textiles used for e.g. tablecloth, upholstery, rainproof clothing and bed linen are treated with these chemicals. 2-3% perfluorochemicals (of the fibre weight) are necessary to obtain water repellence. Bayer, DuPont, 3M and Daikin are some of the important suppliers of the chemicals (Hekster et al. 2002).

In the production of textiles, PFAS substances are also used as wetting agents to e.g. enhance dyeing and as a binder in non-woven fabrics. PFAS substances are also used as e.g. antifoaming agents in textile treatment baths, as emulsifying agents for fibre finishes, and as penetration aids for bleaches (RPA 2004).

For carpets PFOS-related substances have in addition to impregnating agents also been used as carpet spot cleaners (RPA 2004). Well-known soil repellents for carpets are Scotchgard® (3M), Zonyl® (DuPont), Baygard® (Bayer) and Foraperle® (Atofina/DuPont). An average of 15% fluorinated polymers is used for carpet protection (Hekster et al. 2002).

The PFOS-related compounds typically used for textile and carpet surface treatment applications are the acrylate, adipate and urethane polymers of N-ethyl perfluorooctane sulfonamidoethanol (FOSE) (RPA 2004).

Polymeric fluorochemicals are used as water repellents for treatment of leather. Water repellent consumer sprays are also available for leather products. Only about 0.025-0.05% perfluorochemicals (of the leather weight) is necessary to obtain water repellence (Kissa 2001).

RPA – Risk & Policy Analysts Limited, which has prepared the examination behind the risk reduction strategy of United Kingdom for perfluorooctane sulfonate, concludes in their analysis that impregnating agents for use for textiles, leather and carpets today must be regarded as a historical use area. The use of PFOS-related chemicals in impregnating agents is very limited today or is ceased (RPA 2004).

This is in line with the Swedish risk reduction strategy survey on PFOS-related compounds. In 2002, 28% of the total PFOS-related compounds were used as impregnating agents for textiles and leather. However, according to the Swedish suppliers and users, which were asked during the survey, PFOS or PFOS-related compounds are no longer used in impregnating agents (Kemikalieinspektionen 2004)

However, this is somewhat in contrast with the Danish survey on PFOS-related chemicals. According to the Danish survey on use of PFOS-related products (see appendix C) impregnating products for textiles and leather represent somewhere between 16.5% and 30% of the total use of PFOS-related compounds registered in the Danish Product Register [4]. According to the survey impregnating products for leather is the largest group representing between 15% and 28% of the total use of PFOS-related compounds registered in the Danish Product Register (Havelund 2002). However, these numbers do not include imported products and products with a content of PFOS-related substances that are not labelled as dangerous substances.

In most cases, a substitution of PFOS-related chemicals is not carried out in this area in Denmark, even though producers on the market state that impregnation of textile and leather can be carried out without the use of PFOS-related chemicals. Suppliers of chemicals for the textile industry (including production of carpets) state that they have commercially available alternatives to the PFOS-containing products. However, the survey was not able to identify the used alternatives (Havelund 2002). As the Danish survey is two years prior to the UK and the Swedish surveys, this may on the other hand explain the difference, and the possible substitutions can be graining ground on the Danish market as well.

The Danish EPA has initiated a study on different shoe care products with the purpose to identify the substances used in this type of products. The study has been carried out at the same time as this present project, and the results are hence not yet published. The study has examined different shoe care products like e.g. shoe polish and impregnating agents. Impregnating agents represent about 20% of the market of shoe care products. In all 42 different impregnating agents on the Danish market were identified. It is estimated that the identified impregnating products represent the majority of the impregnating products for shoes on the Danish market. Technical data sheets and material safety data sheets were obtained from the suppliers. On the basis of this information, four of the 42 different impregnating products were analysed for a content of eight different PFOS-compounds, due to a suspicion of a possible content of PFOS-compounds. The chemical analysis showed that only one of these four products contained PFOS-compounds in a total concentration of 0.00015% (1.5 mg/kg). This low concentration suggests that the PFOS-compounds are impurities, probably because of a use other fluorinated compounds with shorter chain length or fluorinated telomers. The test results can therefore support the fact that PFOS-related compounds have been substituted in impregnating products for shoes found on the Danish market. However, it was not examined how many of the investigated impregnation products that contained other fluorinated compounds, such as fluorinated telomers (Engelund et al. 2004).

4.2.1.1 Possible alternatives for impregnation of textiles, leather and carpets

According to the Swedish risk reduction strategy on PFOS-related compounds, the alternatives used today in impregnating agents for textiles and leather are based on other highly fluorinated compounds like e.g. polytetrafluoroethylene (PTFE [5]), which is produced by use of PFOA (Kemikalieinspektionen 2004)

For water repellence a mixture of silicones and stearamidomethyl-pyridine-chloride can be used alone as an alternative to PFOS-related compounds or together with a combination of carbamide (urea) and melamin resin (Kemikalieinspektionen 2004).

In June 2003, the 3M Company replaced the PFOS-compound in their Scotchgard products by PFBS (perfluorobutane sulfonate). 3M's Scotchgard products are cleaners and stain protectors for carpets, leather, furniture, automotives, hard surfaces and other apparels. After the phase-out of PFOS in the Scotchgard product, the 3M Company first presented a product in an aerosol-can based on non-perfluoro chemistry. However, the product worked on water but not grease. Therefore, 3M now uses the perfluoro-compound with a shorter chain length – C4 (Fluoride Action Network 2004). The technical properties of PFBS are presented in appendix F.

The Norwegian mass flow analysis of PFAS substances states that regarding impregnating agents for textiles, leather and carpets probably no PFOS-related chemicals are used today. This is based on the fact that 3M has stopped the production of PFOS-related compounds (produces PFBS instead), and that the products by Bayer and DuPont for impregnating carpets neither contain PFOS-related chemicals (but are based on telomers instead with shorter chain length). However, this means that the compounds used instead probably are fluoroalkyl polymers based on telomer-monomers (Statens Forureningstilsyn 2004).

Furthermore, the Norwegian mass flow analysis of PFAS substances states that impregnating agents based on silicone can be used to impregnate textiles (leisurewear and sports wear) and leather (footware). Normally, tablecloths are not impregnated with PFAS substances. Instead polytetrafluoroethylene, also known under trademarks as Teflon® [6], Fluon®, Polyflon®, Vaflon®, is used. Furthermore, a new technology makes it possible to produce carpets with dirt- and water-repellant properties. These properties can be built-in in the synthetic fibres (polypropylene), which are used in the production of carpets. Thereby, use of impregnating agents is unnecessary. However, this technology does not seem to be used yet (Statens Forureningstilsyn 2004).

The possible alternatives identified for impregnation of textiles, leather and carpets are:

  • Highly fluorinated compounds
  • A mixture of silicones and stearamidomethyl-pyridine-chloride
  • A mixture of silicones and stearamidomethyl-pyridine chloride together with carbamide (urea) and melamin resin
  • Perfluorobutane sulfonate based substances (PFBS)
  • Telomer-based polymers
  • Silicone-based products
  • PTFE (polytetrafluoroethylene)

4.2.2 Impregnation of paper and cardboard

Fluorinated chemicals are used in the paper industry to produce water and greaseproof paper. PFOS-related compounds are used both in food contact applications (plates, food containers, bags, and wraps) and in non-food contact applications (folding cartons, containers, carbonless forms, and masking papers) (OECD 2002; RPA 2004).

The main suppliers of fluorochemicals in the paper industry are 3M (Scotchban®), Bayer (Baysize-S/Baysynthol®), Ciba (Lodyne®), Clariant (Cartafluor®) and DuPont (Zonyl®). Their brand names are listed in brackets. It is estimated that 1.0-1.5% fluorochemical (based on the dry weight of the fibres) is needed for paper protection (Hekster et al. 2002).

Paper protection can be achieved by using two different classes of chemistries. One is to use the mono-, di- and triphosphate esters of N-ethyl perfluorooctane sulfonamidoethanol (FOSE) in rough proportions of 10%, 85% and 5% respectively. The second is to use N-methylperfluorooctane sulfonamidoethanol acrylate polymer (RPA 2004).

As for impregnation agents for textiles, leather and carpets, RPA concludes that use of PFOS-related chemicals in impregnating agents is very limited today or is ceased in the UK, but the trend is also believed to have occurred throughout Europe (RPA 2004).

The same conclusion can be seen in the Norwegian mass flow analysis of PFAS substances. No PFAS products are registered in the Norwegian Product Register today, but previously there have been. One producer of greaseproof paper exists in Norway, and according to this producer no PFAS-related substances are used (i.e. no fluorotelomers or perfluorinated substances with shorter chains are used either). The alternatives used instead are not listed (Statens Forureningstilsyn 2004).

This is, however, somewhat in contrast to the Danish survey on PFOS-related chemicals. According to this survey (see appendix C) impregnating products for paper and cardboard represent somewhere between 15% and 28% of the total use of PFOS-related compounds registered in the Danish Product Register. These numbers do not include imported products or products with a content of PFOS-related substances that are not labelled as dangerous substances (Havelund 2002).

According to the Danish survey, a substitution of PFOS-related chemicals is not carried out in most cases, even though players on the market state that impregnation of paper can be carried out without the use of PFOS-related chemicals. However, the survey was not able to identify the used alternatives (Havelund 2002). As the Danish survey is two years prior to the UK and the Norwegian surveys, this may on the other hand explain the difference, and the possible substitutions can be gaining ground on the Danish market as well.

4.2.2.1 Possible alternatives for paper and cardboard

None of the surveys mentioned above has identified the used or available alternatives. The Norwegian survey claims that no PFAS-substances are used in Norway within this area. According to DuPont telomer-based substances are used as alternatives to PFOS-compounds within this area, as DuPont themselves produces telomer-based substances for use in this application area (Personal communication DuPont, 2004a).

The possible alternatives identified for impregnation of paper and cardboard are telomer-based substances.

4.2.3 Cleaning agents, waxes and floor polishes – industrial and consumer products

PFOS-related substances are used/have been used in a variety of industrial and household cleaning products as surfactants. PFOS-related substances are used in cleaning agents, automobile waxes, alkaline cleaners, denture cleaners and shampoos to improve wetting, used in floor polish to improve wetting and levelling, and used in dishwashing liquids and carwashes as a rine-aid (PFA 2004).

According to the UK risk reduction strategy for PFOS, the use of PFOS-related compounds as cleaning agents – both industrial and consumer product – must be regarded as a more or less historical use in the UK. This statement is made, even though it is not clear what alternatives are used today (RPA 2004).

This statement is in line with the Norwegian survey on PFAS-substances that states that PFAS-substances formerly have been used, but are no longer used in cleaning agents. However, in some sprayproducts for cleaning of glass, in waxes and in floor polishes and similar products PFAS-substances are still used. There is no indication if the used substances are PFOS-related substances or other PFAS-substances (with shorter chain length). One producer claims to use a fluorocompound, which is not a PFAS product (Statens Forureningstilsyn 2004).

This statement is somewhat in contrast to the Danish investigation of PFOS-related compounds in Danish products. The Danish survey showed that cleaning agents and polishing compounds are one of the larger use areas. Cleaning agents are alone responsible for about 8% of the total use of PFOS-related compounds, whereas polishes and waxes (including shoe and furniture polish) are responsible for between 0.3% and 9% of the total use of PFOS-related compounds registered in the Danish Product Register. However, according to the survey a substantial amount of substitution has taken place within cleaning products for industrial use, whereas PFOS-related compounds still are used in ordinary cleaning products for the consumer market (Havelund 2002).

According to the Swedish survey of PFOS-related compounds, cleaning agents and floor polish products were one of the larger uses, where PFOS-related compounds are used. According to the survey of the Swedish Product Register 6% of the total amount of PFOS-related compounds was used within cleaning agents and floor polish products in 2002 (Kemikalieinspektionen 2004).

The Swedish survey showed that only one specific PFOS-compound was used in cleaning agents, floor polish and auto polish products. This compound is the potassium salt of glycine, N-ethyl-N-[(heptadecafluorooctyl)sulfonyl] (CAS-no. 2991-51-7). The content in the final product is in general between 0.005 – 0.01% (Kemikalieinspektionen 2004). The Norwegian survey lists a content of fluorinated compound of below 0.01% (Statens Forureningstilsyn 2004). The Danish survey lists a concentration interval, which is about 10 times higher (0.06 – 0.1%), and several different PFOS-related compounds were found in different cleaning agents, waxes and polishes (Havelund 2002).

Today, fluorinated surfactans (such as PFOS) are allowed in the Swan eco-labelled filmforming floor care products. However, the concentration limit is set at 0.01%, and it is indicated that in the future it will be investigated whether it is possible to tighten this requirement (Nordic Ecolabelling 2004). According to the UK risk reduction strategy on PFOS, fluorinated surfactants are accepted in the ecolabelling scheme, as they are difficult to replace (RPA 2004).

4.2.3.1 Possible alternatives for cleaning agents, waxes and floor polishes

According to the website of the 3M Company, 3M produces some alternatives to PFOS-related chemicals, called Novec compounds (se appendix F for further details), which are used in products for commercial and industrial cleaning. These alternative compounds are all fluorinated compounds based on a C4 structure. Examples are methyl nonafluorobutyl ether (CAS no. 163702-07-6) and methyl nonafluoroisobutyl ether (CAS no. 163702-08-7).

One of the contacted companies in search for alternatives, OMNOVA Solutions Inc., manufactures a line of fluorosurfactants (fluorinated polyether) called PolyFox are used in about 40 polish products in the USA, Europe and Asia. According to this company their PolyFox product line can, besides being used as an alternative to PFOS-based products, also be used as an alternative to the long chained telomer based products. The entire PolyFox family of fluorosurfactants are polymers with a molecular weight greater than 1,000. The PolyFox polymers are based on ether links – both the polymer backbone linkages and the link between the backbone and the perfluoroalkyl pendant side chains. The PolyFox fluorosurfactants are synthesized from perfluoroalkyl starting materials with a fully fluorinated carbon chain length of C4 or less. The current first generation products are all made with C2F5 or CF3 perfluoroalkyl side chain structures (Personal communication OMNOVA 2004). The basic structure and the technical properties of the PolyFox products are presented in Appendix F.

Fluorinated surfactants are especially used in water-based floor polish products, as these compounds lower the surface tension and contribute to the formation of a hard film with a good adhesion to the floor, mainly on floors of PVC and linoleum. The advantage of the fluorinated surfactants is that they do not alter any of the other properties of the product (Kemikalieinspektionen 2004).

However, in the last decade the trend has been to use softer waxes, which are a combination of cleaning agents and polish. In these products, the fluorinated surfactants are substituted with non-ionic or anionic surfactants, which have good wetting properties. The advantage of the soft waxes is that they can be applied on top of the old layer of wax, whereas the old and hard waxes (based on PFOS-related compounds) had to be removed before a new layer was added. According to the Swedish sector of cleaning agents, waxes and floor polish, the sector aims to developed non-fluorinated products, but the time where all products will be free from fluorinated compounds could not be determined (Kemikalieinspektionen 2004).

According to the earlier Danish survey on PFOS-related compounds it is assessed that the use of PFOS-related compounds in wax and polish is very difficult to replace. The substitutes may have to be added in a much higher concentration than the fluorinated compounds. Acrylates have been suggested as a general alternative to PFOS-related compounds, also within products as waxes. Furthermore, as the fluorinated compounds have the same function in waxes as in paint, it may be possible to use the same substitutes as within the paint and varnish industry (Havelund 2002).

The possible alternatives identified for cleaning agents, waxes and floor polishes are:

  • Different C4-perfluorinated compounds (e.g. methyl nonafluorobutyl ether and methyl nonafluoroisobutyl ether)
  • Fluorinated polyethers
  • Acrylates
  • A shift to softer waxes may eliminate the use of PFOS-compounds entirely
  • Telomer-based surfactants and polymers

4.2.4 Paint and varnish

PFOS-related chemicals have several uses in paint and varnishes. For example, they can be used as wetting, levelling, and dispersing agents, and may also be used to improve gloss and antistatic properties. They can be used as additive in dyestuff and ink, e.g. as foam generators. Furthermore, they can be used as pigment grinding aids or as agents to combat pigment flotation problems (Kemikalieinspektionen 2004; RPA 2004). According to BASF, fluorosurfactants are, in coatings application, mainly used for substrate wetting, levelling and reduction of surface tension (e.g. in spray applications) (Personal communication BASF 2004).

The information received from different suppliers within the paint and varnish industry suggests that fluorinated surfactants in general are much more expensive alternatives compared to other surfactants. Therefore, fluorosurfactants are only used for special purposes in paint and varnishes, where it is necessary to gain such a low surface tension, which no other (non-fluorinated) alternatives can achieve, e.g. in product where an extremely smooth surface is necessary.

According to the former Danish survey on PFOS-related compounds (Havelund 2002) – see appendix C for further details – paint and varnish represents somewhere between 11% and 12.5% of the total use of PFOS-related compounds registered in the Danish Product Register. Furthermore, the group of printing ink, toner and additives for printing ink additionally represents between 6.7% and 12.6% of the total use of PFOS-related compounds registred in the Danish Product Register. However, the survey also state that a substitution of PFOS-compounds in the paint and varnish industry by and large have been carried out in Denmark. PFOS-related compounds can, however, be present in imported products. The substitution has been carried out over a long period and often entirely new recipes have been developed. Therefore it is not possible precisely to determine, which substances that have substituted the used PFOS-compounds in paint and varnish (Havelund 2002).

This statement is in line with the Swedish investigation on use of PFOS-related substances. Even though the use of PFOS-related compounds was large within the Paint and Varnish Industry in Sweden in 2002, information today from different suppliers in Sweden suggests that PFOS-related compounds no longer are ingredients in paint and varnish products (Kemikalieinspektionen 2004)

According to the UK risk reduction strategy for PFOS, the use of PFOS-related compounds as additive in dyestuff must be regarded as a more or less historical use in the UK. This statement is made, even though it is not clear what the alternatives are today (RPA 2004).

In contrast, PFAS-substances are used in several paint products on the Norwegian market. The substances are used both in waterbased and solventbased paints and varnishes. The amount used is low – below 0.01% (w/w) (Statens Forureningstilsyn 2004). Perhaps the difference lies in the difference between the investigated substances in the different surveys (PFOS-related substances versus PFAS-substances), hereby implying that a use of perfluorinated substances with shorter chain length may still be used in other countries as well? DuPont confirms that telomer-based surfactants are used within this area (Personal communication DuPont 2004a).

4.2.4.1 Possible alternatives for paint and varnish

As mentioned under impregnating agents for textiles, leather and carpets the 3M Company has replaced their PFOS-compounds with C4 compounds, where PFBS (perfluorobutane sulfonate) is the basis. This replacement has also been made within coating products – especially within the area of electronic coating (3M webpage 2004).

The UK risk reduction strategy on PFOS (RPA 2004) mentions that a company in the UK has satisfactorily replaced a fluorosurfactant with a polyether-modified polydimethyl siloxane.

As mentioned under cleaning agents, waxes and floor polishes OMNOVA Solutions Inc. manufactures a line of fluorosurfactants called PolyFox™. The PolyFox polymers can also be used as alternatives to PFOS-related compounds in coating formulations. The PolyFox polymers are based on ether links – both the polymer backbone linkages and the link between the backbone and the perfluoroalkyl pendant side chains. The PolyFox flurosurfactants are synthesized with C2F5 or CF3 as the starting material (Personal communication OMNOVA 2004). For details see the description of the PolyFox compounds in appendix F.

Rütgers Kureha Solvents produces different propylated aromatics (naphthalenes and biphenyls), which can be used as water repelling agents for different applications. For example rust protection systems, marine paints, resins, printing inks, coatings, electrical applications, electronically and mechanical applications (Personal communication RKS 2004). The different propylated aromatics and their technical properties are presented in details in appendix F.

Other possible replacements to fluorosurfactants are silicone surfactants or surfactants based on aliphatic alcohols. BASF produces a range of aliphatic alcohols, both anionic and non-ionic surfactants. However, especially the effect of the non-ionic surfactants is mixed, because these products also are used as defoamers or emulsifiers. So the non-ionic surfactants are difficult to use as replacements for fluorosurfactants. BASF puts emphasis on the following anionic surfactants: a fatty alcohol polyglycolether sulfate and a sulfosuccinate, which under special circumstances may be alternatives to fluorosurfactants (Personal communication BASF 2004). The technical properties of these products are described in details in appendix F.

Worlée-Chemie produces silicone polymers, which in the paint and ink industry in several cases can be used as alternative wetting agents to fluorosurfactants. Two products are emphasized, one being a product based on a non-ionic modified silicone polyether, and the second product is a mixture of a silicone polyether and a diocylsulfosuccinate in ethanol and water (Personal communication Worlée-Chemie 2004). The technical properties of these products are described in details in Appendix F.

The companies Münzing Chemie, Cognis and BASF have all mentioned sulfosuccinates as possible alternatives to fluorosurfactants within the paint and varnish area. Sulfosuccinates are esters of succinic acid (HOOC-CH2-CH2-COOH) in reaction with hydrogen sulfite.

Münzing Chemie has been able to replace fluorobased wetting agents, e.g. in wood primers, with a product based on a sulfosuccinate derivative in ethanol (19%) and water (12.5%) (Personal communication with Münzing Chemie 2004). The technical properties of this product are described in Appendix F.

Cognis has been able to replace fluorobased surfactants based on sulfosuccinates in printing inks, where they are also approved for food contact. Their product is based on the sodium salt of di-2-ethylhexyl sulfosuccinate in ethanol (5%) and water (20%) (Personal communication with Cognis 2004). The technical properties of this product are described in Appendix F.

BASF produces a sulfosuccinate product, which under special circumstances can be used as an alternative to fluorosurfactants within the coating industry. The product is based on di-octyl-sulfosuccinate (di(2-ethylhexyl)-sulfosuccinate) (Personal communication BASF 2004). The technical properties of this product are described in Appendix F.

The possible alternatives identified for paints and varnishes are:

  • Perfluorobutane sulfonate (PFBS)
  • Polyether-modified polydimethyl siloxane
  • Fluorinated polyethers
  • Proplylated aromatics
  • Aliphatic alcohols (e.g. fatty alcohol polyglycolethersulphate)
  • Silicone surfactants / silicone polymers
  • Sulfosuccinates
  • Telomer-based surfactants

4.2.5 Pesticides and insecticides

According to the UK risk reduction strategy for PFOS, PFOS-related compounds have formerly been used in the manufacture of baits for ants and in insecticides against beetles and ants. However, today both associations in the UK and in the EU indicate that its members are not involved in the use of PFOS-related substances in the manufacture of pesticides. Use of PFOS-related compounds in pesticides is thus regarded as a more or less historical use. This statement is made, even though it is not clear what is used (as alternatives) today (RPA 2004).

This is in line with the Danish survey on PFOS-related compounds, where no PFOS-related compounds were found in pesticides products (Havelund 2002). However, the investigation may not cover imported products.

4.2.5.1 Possible alternatives for pesticides

As the use of PFOS-related compounds already has ceased within this area, it has been irrelevant to search for alternatives. No indications have been found in literature regarding alternatives to PFOS-related substances today.

4.2.6 Fire-fighting foams

There are several different types of fire-fighting foams, both fluorine containing foam types and fluorine-free types. Fire-fighting foams containing fluorines are (RPA 2004):

  • FP foams (fluoroprotein foams) used for hydrocarbon storage tank protection and marine applications
  • AFFF (aqueous film forming foams) used for aviation, marine and shallow spill fires
  • FFFP foams (film forming fluoroprotein foams) used for aviation and shallow spill fires
  • AR-AFFF (alcohol resistant aqueous film forming foams), which are multi-purpose foams
  • AR-FFFP (alcohol resistant film forming fluoroprotein foams), which also are multi-purpose foams

According to the UK risk reduction strategy on PFOS any of the above types of fire-fighting foams may contain PFOS-related substances or surfactants (RPA 2004).

Aqueous film forming foams (AFFF) were developed in the 1960's for the purpose of extinguishing flammable liquid fuel fires. Alcohol-resistant aqueous film forming foams (AR-AFFF) were developed in the 1980's to deal with water miscible liquids such as alcohol and petrol containg up to 20% alcohol. They provide a fire-extinguishing film consisting of foam, when mixed with water and air. Monomeric perfluorinated salts are used to contribute to the performance of AFFF as the primary fire-extinguishing chemical and as vapour sealants that prevent re-ignition of fuel and solvent (Moody et al. 2000; RPA 2004). The concentration of perfluorinated compounds in fire-fighting foams is about 0.5-1.5% (Hekster et al. 2002).

Use of fire-fighting foams represents less than 2% of the total fluorochemical use, worldwide according to Buckeye 2001. However, the UK survey of PFOS-related substances states that the use of PFOS-related compounds in fire-fighting foams was 16.3% of the total use of PFOS-related compounds in the UK in 2001 (RPA 2004). In Norway more than 50% of the total use of PFAS-related substances are used for fire-fighting purposes (Statens Forureningstilsyn 2004). In contrast, fire extinguishants represent between 0.3% and 1.1% of the total use of PFOS-related compounds in Denmark according to the data registered in the Danish Product Register (Havelund 2002).

However, today in the UK all fire-fighting foams are manufactured through use of PFOS-free fluorochemicals. As fire-fighting foams have a long shelf life (10<-20 years) PFOS-containing fire-fighting foams are still used in the UK. According to the UK survey only the AFFF and the AR-AFFF foams do contain PFOS-related compounds today, and these foams were manufactured before the 3M Company withdrew their PFOS-chemicals from the market (RPA 2004).

The use of foam-forming fire extinguishers can be divided in two groups: Mobile hand-held fire extinguishers and stationary fire-fighting systems. For the mobile fire extinguishers more environmentally friendly foam has been introduced, at least in Holland where the eco-labelling scheme Millieukeur has been established for these types of products. However, products with the Millieukeur label do not need to be PFOS-free, but contain less PFOS compared to other fire-fighting foams (Hekster et al. 2002). According to a Swedish survey on PFOS-related compounds, new hand-held fire extinguishers do not contain surfactants based on PFOS-related compounds (Kemikalieinspektionen 2004). However, the search for alternatives shows that fluorosurfactants are still used. Now they are just based on a C4 or a C6 chain, which means they are not in the category of PFOS-related compounds (Personal communication DuPont 2004b).

The stationary fire-fighting systems can be based on five different agents (Hekster et al. 2002):

  • Extinguishing Powder
  • Extinguishing gas (CO2, Argon)
  • Protein foam
  • Fluoroprotein foam
  • Synthethic foam

However, when it comes to extinguish a liquid fuel fire, fire-fighting foams with fluorosurfactants are the most effective (Kemikalieinspektionen 2004; Moody et al. 2000). Normally, a mixture of fluorinated surfactant and a hydrocarbon-based surfactant are used in AFFF, as this combination is more cost-effective and performs better than either surfactant separately (Moody et al. 2000).

According to Moody et al. (2000) the use of fluorinated compounds in fire-fighting foams have been reduced, as fire-fighting foams with the sole purpose of using them during training exercises have been developed. These training foams have become popular, as they are cheaper, due to the absence of the expensive fluorinated surfactants.

According to the survey on use of PFOS and PFOS-related substances in Denmark, carried out in 2001 (see a short summary in Appendix C), PFOS and PFOS-related substances were registered in fire-fighting foams in Denmark. In all about 0.3 and 1.1% of the total use of PFOS-related substances registered by the Danish Product Register comes from fire extinguishants. According to the survey, based on information from the Danish Product Register in 2000 [7], perfluoroalkyl sulfonamide aminopropyl derivates and perfluoroalkyl sulfonates are used in fire-fighting foams (Havelund 2002).

4.2.6.1 Possible alternatives for fire-fighting foams

The alternatives to the PFOS-based fluorosurfactants used in existing fire-fighting foams are (RPA 2004):

  • Non-PFOS based fluorosurfactants (these are are based on PFAS-compounds (telomers) with shorther chain length)
  • Silicone based surfactants
  • Hydrocarbon based surfactants
  • Fluorine-free fire-fighting foams, which are

- Synthetic detergent foams (often used for forestry and high expansion applications)

- Protein foams (mainly used for training, but also some marine use)

- Other fluorine free-foams

The fluorine containing fire-fighting foams is used in many cases as they are relatively fluid and provide fast fire extinction. However, Moody et al. (2000) suggests returning to previously used technology such as the protein-based foams, to avoid the use of fluorinated surfactants in fire-fighting foams.

The silicone and hydrocarbon based surfactants are often used in combination with fluorosurfactants to achieve higher performance levels in actual fire situations. Used alone the silicone and hydrocarbon based surfactants provide the lowest technical suitability of the potential alternatives and hence are not real alternatives to fluorosurfactants (RPA 2004). It is important to notice that foams without fluorinated surfactants cannot reach the level of performance obtained with foams containing fluorinated surfactant compounds. Fire-fighting foams made from fluorinated surfactants have technically shown to be the only technology, which can quickly and effectively extinguish fires from highly combustible and flammable materials (Fire-fighting Foam Coalition 2001). Therefore, the only real alternative to the PFOS-based fire-fighting foams is the PFAS-based fluorosurfactants.

The PFOS-free fire-fighting foams used today are unlikely free from fluorinated compounds, but are based on PFAS-compounds with C6 or C4 chain length.

As described earlier, the 3M Company started to phase out the production of PFOS chemicals in the year 2000 and manufactures today perfluorinatede chemicals with shorter carbon chains (compared to PFOS – a C8-chemical). According to the website of 3M a C6-fluorinated compound is used in their Fire Protection Fluid. The compound is dodecafluoro-2-methylpentan-3-one (CF3-CF2-C(=O)-CF(CF3)2). (See more specific description in Appendix F) (3M webpage, 2004).

DuPont manufactures telomer-based compounds of shorter carbon chains – e.g. C6-compounds. According to DuPont, their fluorosurfactants used for fire-fighting foams are based predominantly of a C6-telomer. Depending on the product the content of fluorinated C6-telomer is between 65 and 95% (Personal communication DuPont 2004b). This means that the rest (5-35%) of the fluorinated telomers in the products is either fluorinated telomers with higher or lower carbon chain (possibly a part may still be C8?). No such information about the purity of the C6 compound of 3M was available (See more specific description in Appendix F).

The survey on PFOS-compounds from the UK states that the fluorine-free foams are a relatively new technology today. These fluorine-free foams are used in training exercises, for shallow spill fires, but are also suitable for flammable liquid fires in line with the PFOS based or telomer based fire-fighting foams. Some information suggests that the fluorine-free foams may not currently achieve the same standards of PFOS based fire-fighting foams on a few chemical properties, but an European foam producer indicates that it produces fluorine-free foams that perform as well during testing as PFOS based foams. The producer indicates that these foams are widely used in Australia, Singapore, New Zealand and other parts of the world (RPA 2004).

A Swedish investigation on the subject shows that fire-fighting foams with the content of PFOS-related compounds were removed from the (Swedish) market in 2003. The alternatives were highly fluorinated telomers, but no CAS-numbers could be identified. The fire-fighting foams are today predominantly based on C6F13, but it is possible that the fire-fighting foam contains C8F17 – a PFOS-related compound (Kemikalieinspektionen 2004).

Similarly, the Norwegian survey on PFAS-compounds states that PFOS-related compounds are not likely to be used anymore in fire-fighting foams, as fire-fighting foams now most likely are based on telomer-compounds with shorter chain length. In Norway the AFFF fire-fighting foams are mainly used in offshore installations, at oil refineries, at tankers, at airports and similar places where kerosene products and other flammable liquids are used and stored. Over 50% of the total use of PFAS-compounds [8] in Norway is due to the use of fire-fighting foams, and use of fire-fighting foams in offshore installations represents more than half of the use of fire-fighting foams (Statens Forureningstilsyn 2004).

According to Falck Denmark (the department Falck Teknik), Denmark uses about 10 tons of fire-fighting foam for land use per year, i.e. not counting use on ships and oil platforms. Formerly, the annual amount was as high as 30 tons for land use, but with a stop of fire-fighting foam for use in fire training exercises, the use has fallen drastically (Personal communication Falck Teknik 2004).

Falck Denmark alone uses less than 5 tons fire-fighting foam annually. Falck Denmark imports and sells fire-fighting foams to the fire department of Copenhagen (Københavns Brandvæsen). According to Falck, no fluorinated compounds are present in the fire-fighting foams that Falck imports from Sthamer in Germany. Their fire-fighting foam is based on either protein foam or syntethic foam (Personal communication Falck Teknik 2004).

Two other companies cover the last 40-50% of the fire-fighting foam market in Denmark. One of these companies was contacted (wanted to be anonymous). Formerly, their fire-fighting foams did contain polyfluorinated compounds supplied by the 3M Company. However, when 3M stopped its production, they in stead imported fire-fighting foams from Solberg Skandinavien, a company located in Norway. The Danish importer was not aware that the fire-fighting foams contained fluorinated compounds or not. According to the website of Solberg Skandinavien [9], they sell fire-fighting foams both with and without fluorinated compounds

According to Solberg Skandinavien their fire-fighting foams AFFF and AR-AFFF are not based on PFOS-related compounds. The fluorinated surfactants, which according to their MSDS's all are based on a polyfluoroalkyl betaine, are telomer based (Personal communication Solberg Skandinavien 2004). It is not clear, which telomers their fire fighting foams are based on, but they are most likely a blend of telomers with different chain lengths as is the case for the DuPont produced telomers.

Copenhagen Airports (which covers both the airports in Kastrup and in Roskilde) solely use AFFF foams for fire-fighting purposes. The foams are purchased by Solberg Skandinavien and are PFOS-free, but fluorotelomer based. However, for training purposes special training fire-fighting foams – foams without fluorine - are used. An estimated amount of 1000 litres of training foam is used annually.

The vehicles used by Copenhagen Airports for fire extinguishing and training purposes contain both AFFF foam with fluorine, and the special training foam without fluorine. Twice a year Copenhagen Airports are obligated to check the vehicles. In these cases the AFFF foam with fluorine is used, but the foam is gathered by use of coal filters, which are then send to special chemical treatment (at KommuneKemi, Denmark). For each check of the vehicles it is estimated that about 50-70 litres of fluorine containing AFFF foam are used (Personal communication Copenhagen Airports 2004).

Part of the offshore industry in Denmark, which operates in the North Sea, has also been contacted. One (of three) company has informed that they use AFFF fire-fighting foams at the offshore installations. The AFFF foams used are all containing fluorosurfactants, and their supplier informs that the fluorosurfactants are based on fluorinated telomers (i.e. mainly C6 fluorinated compounds) (Personal communication 2004).

The Danish Navy was contacted in order to learn about their use of fire-fighting foams (Personal communication the Navy 2004). Four different fire-fighting foams are currently used in the Danish Navy, in the Danish Air force and in the Danish Army. Three of the four fire-fighting foam products are AFFF products, which means they are based on fluorinated surfactants. The Navy and the Air force are using two and one of the three different AFFF products, respectively.

All three organisations also use a fire-fighting foam product called Sthamex F-15 (from Sthamer in Germany). According to Sthamer in Germany this product does not contain any fluorinated surfactants (Personal communication Sthamer 2004). Sthamex F-15 is used by the Navy in real fire situations on board ships, and is also used by the Army in real fire situations.

Common for the Navy and the Army is that all relevant personnel is educated at a training school HVIMS, which is using a non-fluorinated fire-fighting foam called Biofoam T (obtained from Hauberg Technique) for education and training purposes (Personal communication, the Navy 2004). According to Hauberg Technique, supplier of the Biofoam T fire-fighting foam, none of their fire-fighting foams contain fluorinated compounds. (Personal communication, Hauberg Technique 2004).

The possible alternatives identified for fire-fighting foams are:

  • C6-fluorinated compounds (e.g. dodecafluoro-2-methylpentan-3-one).
  • A mixture of different C6-fluorinated telomers (possibly with some C8-fluorinated compounds as well).
  • A return to the previous technology of e.g. protein-based foams or synthetic detergent foams (which will not be as effective for flammable liquid fuel fires).

4.2.7 Photographic industry

In the photographic industry PFOS-related compounds are used in the manufacturing process of film, photo paper and plates. The PFOS-related compounds function as dirt rejecters and friction control agents. Furthermore, they reduce surface tension and static electricity. Imaging materials that are more sensitive to light (i.e. high speed films) are more in need of the properties provided by PFOS based materials (RPA 2004).

The concentration of PFOS-related substances in coatings in films, paper and plates is in the range of 0.1-0.8 μg/cm2. Due to a reduction of the use of films (caused by use of digital cameras), the use of PFOS within this area is not expected to grow (RPA 2004).

Electronic products as cameras, printers, scanners etc. do not contain PFOS-related compounds (RPA 2004).

Furthermore, PFOS-related compounds have been used in developers for photo films according to a Swedish survey. However, the survey suggests that this use is no longer relevant. No information about the alternative products was found (Kemikalieinspektionen 2004).

In Denmark between 0.2% and 1.1% of the total use of PFOS-related compounds registered in the Danish Product Register is due to the use of photo developers (Havelund 2002).

4.2.7.1 Possible alternatives for the photographic industry

According to the UK reduction strategy for PFOS-related compounds, the work of substituting PFOS-related compounds within the photographic industry has been ongoing since the year 2000 (where the 3M Company ceased their production of PFOS compounds). This work has resulted in a reduction of 83% of the use of PFOS-related compounds within this industry. This reduction is primarily due to a change to digital techniques, where a dry process technique is used (RPA 2004).

The alternatives that have replaced the PFOS-related compounds are telomer products and chemicals with short perfluorinated chains such as C3 and C4, but also non-fluorinated chemicals such as hydrocarbon surfactants and silicones (RPA 2004)

For the remaining use of the PFOS-related compounds within the photographic industry no alternatives have been identified so far. These uses are surfactants, electrostatic charge control agents, friction control agents, dirt repellent agents and adhesion control agents for mixtures used in coatings applied to films, papers, and printing plates (RPA 2004).

The possible alternatives identified for the photographic industry are:

  • Telomer-based products
  • C3 and C4 perfluorinated compounds
  • Hydrocarbon surfactants
  • Silicone products.

4.2.8 Manufacturing of semiconductors

PFOS/PFAS based chemicals are used in the fabrication of imaging devices such as digital cameras, cell phones, printers, scanners etc. Manufacture of print plates is a lithographic process. In this process PFOS-related compounds are used because of their surface-active properties, and as they are able to resist the strongly acidic conditions. The PFOS compounds are used in photo-acid generators (PAGs), in antireflective coatings (ARC), and as surfactants in developers, etch mixtures and commercial photoresists (Kemikalieinspektionen 2004; RPA 2004)

The PFOS-related compounds are a part of the process chemicals and are not a part of the final products (RPA 2004)

4.2.8.1 Possible alternatives for manufacturing of semiconductors

According to the European Semiconductor Industry Association new techniques are being developed where PFOS-related substances are not being used. However, these techniques are not yet ready for commercial use and will not be for the next 2 to 5 years. The most critical manufacturing processes are photoresist (PAG) and anti-reflex treatment (Kemikalieinspektionen 2004; RPA 2004).

4.2.9 Hydraulic oils within the airplane industry

Hydraulic oils are used in airplanes to cause a break pressure. However, the early used hydraulic oils could cause fires for which reason perfluorinated surfactants are added. Use of perfluorinated compounds in the hydraulic oils also has the function that they prevent corrosion by lowering the surface tension. Hydraulic oils with a content of perfluorinated compounds are used in both civil and military airplanes all over the world (Kemikalieinspektionen 2004).

A specific compound is used in the hydraulic oil – the potassium salt of perfluoroethyl cyclohexyl sulfonate (CAS-no. 67584-42-3). Per definition, this compound is not a PFOS-related compound, but is a part of the large PFAS group (perfluoroalkyl substances) (RPA 2004). The content of the substance in the used hydraulic oils is about 0.1% (Kemikalieinspektionen 2004). The total global market for fluorinated compounds in aircraft hydraulic fluids is about 2.2 tonnes per year (RPA 2004).

4.2.9.1 Possible alternatives for hydraulic oils within the airplane industry

A search for alternatives within this area has been going on for 30 years and about 2500 different compounds have been tested. Unfortunately, no compounds have been useful, meaning that no alternatives have been identified. The not fully fluorinated telomers have not met the required demands and cannot be used as alternatives even though the chemistry is similar to that of PFOS based compounds (Kemikalieinspektionen 2004). Today the only possible alternative to the above mentioned fluorinated substance is potassium perfluorooctane sulfonate, and there is no known alternative chemistry, which will provide adequate protection to the aircrafts (RPA 2004).

A change in the formulation of the hydraulic oils seems to be the only alternative solution. This will, however, demand a comprehensive testing together with an approval from the airplane manufacturers, which may take as long as 10 years, as the safety measures within this industry are very high (Kemikalieinspektionen 2004).

According to the UK risk reduction strategy on PFOS, manufacturers of hydraulic fluids used in the airplane industry are looking for manufactures that would be willing to produce the needed PFOS substances, when the existing stocks are exhausted. The 3M Company formerly produced the potassium salt of perfluoroethylcyclohexyl sulfonate used in hydraulic fuels, but they also withdrew the production of this substance from the market (RPA 2004).

4.2.10 Metal surface treatment

For the metal surface treatments called chromium plating and chromating PFOS-related compounds are used to lower the surface tension of the chromium bath. The PFOS-related compounds act as a barrier over the chromium bath and will prevent an emission of chromium (VI) aerosols. The aerosols are a health risk, as chromium (VI) is carcinogenic (RPA 2004).

PFOS-related substances used for mist suppression in metal plating baths are the potassium, lithium, diethanolamine, and ammonium salts of perfluorooctane sulfonic acid, as well as quaternary ammonium salts and amines. According to the UK survey the quaternary ammonium salt of PFOSA (CAS No. 56773-42-3) seems to be used the most. Typically, 10% solutions of PFOS-related substances are used for metal plating. An estimation of the PFOS-related substances for use within the metal plating industry in the EU is between 8.6-10 tonnes per year. Important applications for chromium plating include aircraft, medical industries, vehicles and general engineering (RPA 2004).

In Sweden about 3% of the PFOS-related compounds used in 2002 was used for metal surface treatment (Kemikalieinspektionen 2004). According to the Danish report on use of PFOS-related chemicals, between 0.6 and 2.3% of the total use of PFOS-related chemicals was used for metal surface treatment. Another 3.5% of the total use of PFOS-related compounds registered in the Danish Product Register was used within the area of electroplating and galvanization (Havelund 2002).

Besides the use for chromium plating, which is the main use, fluorinated surfactants are also used as (RPA 2004):

  • Agents to prevent haze of plated copper (by regulating foam and improving stability).
  • Non-foaming surfactants in nickel-plating baths (to reduce surface tension).
  • Agents added to tin-plating baths (to produce a plating of uniform thickness).
  • Agents to impart a positive charge to fluoropolymer particles and to aid electroplating of the polymer (e.g. PTFE) onto steel for surface protection.

In the area of surface coating, PFOS-related compounds and PFOA are found in products, which are surface coated with fluoroplastics (PTFE, PVDF and other fluoropolymers). At the moment no PFOA-free PTFE-dispersion is available on the market, but all the big suppliers of PTFE have started to work on possible alternatives. However, at the moment there seems to be no satisfying alternative to PFOA in the production-process of PTFE (Personal communication – surface treatment company 2004; Personal communication DuPont 2004a).

4.2.10.1 Possible alternatives for metal surface treatment

At the moment, EU funded research is trying to identify alternatives, as use of chromium(VI) is a serious health risk (carcinogenic) in the chromium-plating and chromating processes. If alternatives to chromium(VI) can be found the use of PFOS-related chemicals is most likely eliminated within the area of metal surface treatment (Kemikalieinspektionen 2004; RPA 2004).

An alternative process already exists for decorative chromium plating. In this process chromium(III) is used instead and no PFOS-chemicals are necessary. However, the problem is that the process with chromium(III) does not function as well for hard plating. Instead larger closed tanks or increased ventilation are suggested as (expensive) alternative solutions for the applications where a use of chromium(III) is not possible yet (Kemikalieinspektionen 2004; RPA 2004)

4.2.11 Plumbing – fluxing agents

The search in the Danish Product Register for use of PFOA salts and telomer alcohols, performed in this project (see detailed description in Appendix D and E), shows that the PFOA ammonium salt and the telomer alcohol perfluorooctanol are the only two substances, which are found in products reported to the Danish Product Register of the PFOA salts and of the telomer alcohols. These two compounds are both found in fluxing agents, which are used for plumbing with leaded soldering tin.

According to the Danish survey on use of PFOS-related compounds fluxing agents for plumbing represent about 0.3% of the total use of PFOS-related compounds registered in the Danish Product Register (Havelund 2002).

4.2.11.1 Possible alternatives for plumbing – fluxing agent

One of the companies selling fluxing agents with a content of fluorinated compounds was contacted (see Appendix E for a more detailed description). According to this company the fluxing product will automatically go out of use in a couple of years as the "European Directive 2002/95/EC of January 27 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment" states that after July 1st 2006 lead is no longer permitted in electrical and electronic equipment (Directive 2002/95/EC 2003).

Today plumbing is carried out with the use of soldering tin that consists of 63% lead and 37% tin. When using this leaded soldering tin it is necessary to use a soldering flux to prepare the surface for the plumbing. Fluxing agents are used in automatically closed systems and are sprayed on the object, which is heated (to remove the fluxing agent), and then the plumbing is carried out.

The alternatives to leaded soldering tin are use of soldering tin of either pure tin or soldering tin with a small percentage of silver and copper, 0.7% and 3.5% respectively. With a use of lead-free soldering tin it is, however, possible to use water-based fluxing agents instead of the solvent based fluxing agents (with perfluoro compounds). This means that the use of perfluoro compounds in fluxing agents automatically will cease with the implementation of lead-free plumbing.

4.2.12 Other uses

The risk reduction strategy of PFOS-related compounds made by the UK has identified a few other uses of PFOS-related compounds. These are:

  • Medical applications (for waterproofing of surgical items such as gloves, masks, drapes and undersheets).
  • Flame-retardants (as additives to provide water and stain repellence).
  • Surfactants in the oil industry (e.g. to enhance the amount of metal recovery in copper and gold mines, to enhance oil or gas recovery in wells or as evaporation inhibitors for gasoline, jet fuel, solvents and hydrocarbons).
  • Adhesives (for specialty tapes and low adhesion backs for industrial tapes).

These applications have been identified outside the EU and as more historical uses for which reason they are not described in further details (RPA 2004).

Furthermore, telomer alcohols are used in chemical analysis. Fluorous Technologies, Inc. describes that fluorous techniques are used for the synthesis and separation of organic molecules in reaction mixtures (Fluorous Technologies 2004).

Footnotes

[3] Please notice that the UK survey maps the use of PFAS chemicals and not just only PFOS-related compounds. This may explain why the fire-fighting foams are represented with such a relatively high percentage, as this is an area where the use of PFAS substances with shorter chaing length (not PFOS) is gaining ground today.

[4] It is not indicated in the report (Havelund, 2002) when the information from the Danish Product Register is from, but it is probably from the year 2000.

[5] Teflon®, Fluon®, Polyflon®, Vaflon® are all examples of brand names of PTFE.

[6] It should be noted that Teflon® is a consumer brand which describes performance in consumer products. While PTFE (polyetetrafluorethylene) containing cookware is often branded Teflon®, many Teflon® branded items do not contain any fluorinated materials.

[7] The report does not indicate when the information from the Danish Product Register is from, but it is probably from the year 2000.

[8] Please notice that this survey calculates the total use of PFAS-compounds where other surveys focus on the use of PFOS-related compounds that do not include lower carbon chain products as C4 and C6 fluorinated compounds.

[9] www.articfoam.com

 

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