Document 9geyR9yEpx6oJ32zo0vVQ3Ze

Classification: General Business Use SHPP's Inputs to the Public Consultation Comments to Annex XV PFAS Restriction Proposal Question number 6: Missing uses: PTFE Used as an Anti-Drip Additive in Flame Retardant Polycarbonate Resins and Blends for Electrical Applications Executive Summary SABIC's Specialties business (SHPP) produces a range of highly differentiated products, including high-performance thermoplastics, compounds, and additives that meet complex thermal, mechanical, optical, and electrical property requirements. Flame retardant polycarbonate (FR PC) resins and blends with Polytetrafluoroethylene (PTFE) anti-drip additives play a safety-critical role while providing functionality in electrical applications, such as high voltage safety switches and circuit breakers. These FR PC resins and blends used in such applications are inherently tough materials in harsh environments and provide device integrity, especially during cold temperature impact events and maintenance activities, so the device continues to function properly and does not produce an electrical hazard (short circuit, shock hazard) or a fire hazard. Because these plastics are inherent insulators, they also provide a needed significant reduction in electrical shock resistance when used in these high-voltage applications and help prevent electrocution of people in home or industrial environments. By increasing ignition resistance, the PTFE used in FR PC resins and blends helps prevent injuries and property damage by lowering the probability of a fire event. If a flame event does occur, they help prevent the loss of life and property by reducing the risk of a small fire growing out of control. Since the application product lifetime of such applications in, for example, switch boards, is very long and typically no preventive maintenance or replacement is planned, it is imperative that all safety and functionality advantages must be maintained over a very long time. Most applications are used in indoor environments, which mainly include exposure to temperature fluctuations, including low temperatures and moisture. The specific devices where these FR PC resins and blends with PTFE anti-drip additives are used (for example high-voltage safety switches and circuit breakers) all see high voltages. A failure of such devices at least would compromise the system functionality, but it could also lead to immediate fire hazards and immediate or hidden shock hazards to anyone interacting with the system - maintenance, repair, adjacent activities, etc. Furthermore, it is important that these materials are inherently tough and ductile at both room and sub-ambient temperatures, such that the components made from these materials are not damaged during assembly, transportation, and being inadvertently dropped. This could affect the lifetime of the component and the long-term safety of these devices. SHPP's extensive research has not found any alternatives that provide adequate flammability performance for FR PC resins and blends while also maintaining adequate impact resistance and ductility, cold temperature impact retention, long-term temperature/moisture exposure, and Classification: General Business Use electrical tracking resistance. If an alternative is found, material qualification testing will be needed, companies may need to make changes to their manufacturing equipment and processes to use the new material, and part qualification testing would be needed. Given the absence of alternatives, SHPP feels it would be appropriate to allow for a 12-year derogation to have sufficient time to invent new materials or develop viable alternatives for PTFE used as an antidrip additive in flame retardant polycarbonate resins and blends, and to have sufficient time for the steps needed to make and qualify final parts. Emissions of PTFE during the use phase of final products are negligible because PTFE is bound within the PC resins and blends. The emissions in the waste stage depend on the pre-treatment method. A recent review published by the Society of Environmental Toxicology and Chemistry (SETAC) in 2023 shows that PTFE does not release substances of toxicological or environmental concern, and fluoropolymers are stable and not expected to transform to dispersive nonpolymeric PFAS. Substance Information Substance Name: Poly(1,1,2,2-tetrafluoroethylene) Synonyms/Abbreviations: PTFE Molecular formula: (C2F4)n EC/List no.: 618-337-2 CAS number: 9002-84-0 Type: Solid Application: PTFE used as an anti-drip additive in flame retardant polycarbonate (FR PC) resins and blends for electrical applications 2 Classification: General Business Use Table of Contents Executive Summary 1. Technical description.........................................................................................................3 1.1 Application description.............................................................................................4 1.2 Function of material/article and PFAS content......................................................5 1.3 PFAS properties required in material/article.........................................................6 2. End-of-Life.........................................................................................................................7 2.1 Concerning Exposure to the Environment .............................................................8 3. Availability of substitutes...................................................................................................9 3.1 Alternative applications............................................................................................9 3.2 Alternative substances ..............................................................................................9 4. Development of possible substitutes................................................................................11 4.1 Actions taken to develop alternative applications or alternative substances ....11 4.2 Stages and timeframes needed to establish possible substitutes .........................12 5. Request for derogation for use of PTFE as an Anti-Drip Additive in Flame Retardant Polycarbonate (FR PC) Resins and Blends for Electrical Components...............................12 1. Technical description 3 Classification: General Business Use 1.1 Application description SABIC's Specialties business, SHPP B.V. (hereafter "SHPP"), produces a range of highly differentiated products, including high-performance thermoplastics, compounds, and additives that meet complex thermal, mechanical, optical, and electrical property requirements. PTFE-containing flame-retardant polycarbonate (FR PC) resin and blends are commonly used in electrical applications, such as high-voltage safety switches and circuit breakers. These compounds typically comprise a neat base polycarbonate resin or blend, a flame retardant, and a PTFE polymer, which serves the purpose of an anti-drip additive during a potential fire event. Additionally, these FR PC formulations may include other additives and pigments. FR PC resins and blends containing PTFE are a semi-finished product in the form of plastic pellets that are subsequently injection moulded or extruded into shapes and final parts. The primary purpose of these compounds is to provide flame-, electrical-, and impact-resistance to electrical device components and to help ensure the safe, reliable functioning of the applications such as circuit breakers over the long lifetime of the device. These compounds are in many cases optimized for the specific requirements of the final applications. Some examples include: Excellent flame resistance High-voltage electrical properties - including electrical tracking resistance Cold temperature impact and ductility/flexibility Overall mechanical / impact strength Electrical insulation Temperature resistance / long-term thermal aging Weather resistance (retention of properties) - UV and water exposure, in case of outdoor usage No breakage during short circuiting High continuous use or peak temperatures Corrosion resistance Full color space to allow safety or branding colors High flow capability to produce complex and/or thin wall devices Over the past 20+ years, FR PC resins and blends using PTFE as an anti-drip additive have been utilized in electrical applications due to their differentiated properties. Typically, these applications and the materials used to produce them must undergo complex and extended-life testing and meet demanding regulatory and industry prevailing standards requirements to ensure their safety and functionality throughout their expected or mandated lifespan. The moulds used to fabricate the electrical device components using the PTFE FR PC resins and blends are often complex and designed to fabricate parts to very tight tolerances and to fulfil the applications' technical and regulatory requirements. Any significant change in composition/formulation of the compound, such as eliminating the PTFE and/or replacing it 4 Classification: General Business Use with a possible alternative, could result in needing to modify or replace the moulds to produce parts with the same final design and geometry. Furthermore, the final assembly would often need to be completely re-tested and re-specified to ensure proper functioning over its lifetime. In highly regulated, safety-critical, long-lasting (expected to last 20 years or more) electrical applications, new materials often require extensive and severe long-term testing, which can take several years of testing and validation to complete a substitution. A key example of such a test is the RTI (Relative Temperature Index), which typically takes about a year to complete testing, but could take up to 2 years if no direct comparison material is available. Then customer-specific testing would be needed to qualify a new material in each separate application. Given the re-testing and re-specifying, coupled with changes in design and production, part substitution can easily take several years to complete, and the more complex devices could extend the timeline further. Some examples of current commercial applications of FR PC resins and blends with PTFE anti-drip additives are described below. Circuit breakers are electrical safety devices, that automatically interrupt the current of an overloaded electric circuit, ground faults, or short circuits. Circuit breakers "trip" or shut off current flow after protective relays detect a fault, protecting the electrical installation and equipment from being exposed to high currents that potentially result in devices and electrical wiring overheating, causing damage, losing functionality and/or catching fire. Disconnect switches are used to isolate areas in the electrical system from receiving current and are integral to the safety of an electrical system. They can be manually or remotely operated and are generally used in maintenance and repair situations. Unlike a circuit breaker, they are meant to be used routinely and can be specific to the part(s) of the system they are isolating or general to a location. For example, an industrial air-conditioning unit could have a dedicated manual switch to shut off current to the unit for repair or maintenance. Also, an entire building could have a single disconnect switch. In these cases, the switches are often in locations near the unit or areas they are isolating, which could be outdoors. 1.2 Function of material/article and PFAS content PTFE anti-drip FR PC resins and blends provide a combination of flammability performance with minimal flame retardants to preserve electrical properties, cold temperature impact resistance and other mechanical properties, heat resistance, and more. These properties facilitate maintenance-free, reliable, and proper functioning of safety-critical components over a long lifetime that can be up to 20 years or more. In general, flame retardant additives are only added for flame performance and could lessen other properties such as impact, ductility, and outdoor weather performance. The PTFE preserves those other necessary properties. PTFE as an anti-drip agent is typically used in the range of 0.1-0.5% by weight. 5 Classification: General Business Use Due to the high voltages and currents involved, electrical systems like circuit breakers have a risk of fire and a risk of electrical shock. There are many safety standards in place to help mitigate these risks. The most important standard for electrical applications is "UL 94, the Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances"1 that is now harmonized with IEC 60707, 60695-11-10 and 60695-11-20 and ISO 9772 and 9773. Different levels of material flammability classifications exist and are used in electrical applications. FR PC resins and blends are typically used where classifications of V-0 or 5VA/B are required at the given part thickness in applications such as enclosures, structural parts, and electrical insulators. Both ratings require that samples do not drip flaming particles during the tests. Since thermoplastics are designed to be shaped/flowed by heat, direct flame application can lead to melting and dripping before or during ignition. Any flaming melting/dripping has the chance of spreading flame beyond the initial event and is almost always more pronounced in thinner rather than thicker gauges of thermoplastics, all else being equal. Based on Table 2 (section 4.1), PTFE is the only viable additive that can inhibit dripping and retain all the other properties necessary for electrical applications. 1.3 PFAS properties required in material/article The PFAS used in these types of formulations is a fully fluorinated polymer Polytetrafluoroethylene (PTFE). The types of PTFE used as an anti-drip/enhanced structural integrity additive for thermoplastic compounds help the overall FR additive package by providing the following key product attributes: Increased resistance to ignition Reduced rate of flame spread once a fire has started FR formulation strategies for thermoplastics typically are combinations of multiple additives. These generally fall into two classes that typically work synergistically: flame suppressants and anti-drip additives. PTFE additives provide a unique, critical role as structural integrity/anti-drip agents, which allow for minimal FR additives. During melt processing where high mechanical shear exists, PTFE compounds that are designed to be anti-drip additives do not melt but undergo a physical form change from being semi-spherical particles to highly elongated fibrils in this high temperature, high shear environment. These very high aspect ratio fibrils form an entangled network inside the polymer matrix. During a flame event, this network does not burn/ignite but helps promote char formation and provides much higher melt strength to the plastic part, significantly improving resistance to deformation and/or loss of structural integrity as the polymer matrix burns (e.g., no flaming drips and enhanced resistance to further heat release from the flame initiation point). 1 https://www.shopulstandards.com/ProductDetail.aspx?productId=UL94_6_S_20130328 6 Classification: General Business Use A non-exhaustive list of other properties that make a PTFE anti-drip additives in FR PC resins and blends differentiated materials in electrical applications are: high softening temperature allowing exposure to high service and/or peak temperatures without affecting performance high resistance to thermal degradation, maintaining fire resistance properties and toughness over long lifetimes resistance to typical chemicals used in assembly or cleaning very low surface energy electrically non-conductive to allow electrical insulative properties inert reactivity due to perfluorinated structure and high molecular weight. high toughness, also at low temperatures, which may help prevent part failure or breakage during short circuiting full color space to allow safety or branding colors high flow capability to produce complex and/or thin wall devices high dielectric strength retained over range of low and high operating temperatures. As an anti-drip additive in FR PC resins and blends, PTFE is generally used in loadings of 0.10.5 wt% of the bulk compounded product. Since the density of a perfluorinated polymer is higher than that of the base resin, the volume fraction of PTFE is lower than the weight percentage cited. One key electrical property requirement of electrical device components is the Relative Temperature Index (RTI) Test (which is measured per the UL 746B standard). This test is used to assess the resistance of plastic materials to thermal degradation and to help ensure that properties such as flame and electrical resistance, and mechanical strength are retained for safe operation and functionality. Compared to many alternatives, FR PC resins and blends have high RTI values of 120-130C, often required in applications like switches and circuit breakers. A relatively simple RTI test takes 8-10 months, plus additional time for sample preparation and logistics (which can add another 3 months to the process). More complex RTI tests, especially when an appropriate reference material for comparison is not available (example, for new materials), can extend up to 2 years. PTFE as an anti-drip additive is exceptional in that it is highly resistant to thermal degradation, does not migrate out of the FR PC resins and blends when exposed to water, and does not significantly change other properties while improving flame performance. 2. End-of-Life 7 Classification: General Business Use Emissions during the use phase of final articles are negligible, because PTFE is bound within the polymer. However, it is understood that anti-drip PTFE in products will eventually enter the waste stage with levels in the polymer matrix at 0.1-0.5% by weight. 2.1 Concerning Exposure to the Environment A recent review published by the Society of Environmental Toxicology and Chemistry (SETAC) in 2023 states that emissions of PTFE during the use phase of final products are negligible because PTFE is bound within the polymer. The emissions in the waste stage depend on the pre-treatment method. PTFE does not release substances of toxicological or environmental concern, and fluoropolymers are stable and not expected to transform to dispersive nonpolymeric PFAS. When the articles containing PTFE anti-drip additives reach their end-of-life, various waste (pre-) treatment methods are commonly practiced by the industry, e.g., recycling/re-use, landfilling and incineration. Thorough incineration will decompose PTFE without formation of non-polymeric PFAS. When recycling/reuse and landfilling are chosen, polymeric PTFE remains as a fluoropolymer that is not water soluble or mobile and therefore, does not present the specific risks nor hazards as those of non-polymeric PFAS. There is considerable data demonstrating that PTFE do not release substances of toxicological or environmental concerns2. In contrast to non-polymeric PFAS, PTFE being a polymeric material is chemically, thermally, and biologically stable and therefore is not expected to transform to dispersive nonpolymeric PFAS when disposed of in landfill. A recent study presented results from OECD guideline biodegradation studies demonstrating that PTFE is stable under environmentally relevant conditions. Furthermore, fluoropolymers that meet the criteria to be considered Polymer of Low Concern (PLC), have negligible leachables, unreacted monomers, and oligomers most likely destroyed in fluoropolymer use processing and would therefore not be expected to significantly contribute to landfill leachate. Available data reveal that fluoropolymers are mineralized (i.e., all C-F bonds broken, hydrofluoric acid generated, and scrubbed to calcium fluoride) under commercial Waste-toEnergy (WtE) incineration operating conditions. In recent pilot scale studies representative of full-scale WtE facilities, the most common form of end-of-life destruction conducted on PTFE found that combustion converted the fluorine into controllable hydrogen fluoride gas and that, of the 31 PFAS studied, no fluorine-containing products of incomplete combustion were produced above background levels. Further, a recent study investigating the presence of PFAS in waste incinerator flue gas stated: "based on a literature review, RIVM (the Dutch National Institute for Public Health and the Environment) expects that most of the PFASs will largely degrade during the incineration process and then be removed when the flue gases are cleaned. 2 A critical review of the application of polymer of low concern regulatory criteria to fluoropolymers II: Fluoroplastics and fluoroelastomers. Integr Environ Assess Manag, 19: 326-354. https://doi.org/10.1002/ieam.4646 8 Classification: General Business Use The remaining PFASs are expected to be removed during the recovery of the carbon dioxide". The RIVM report3 affirmed that PTFE is the most stable fluorine-containing polymer. The RIVM report concluded that complete thermal decomposition of PTFE is achieved at a temperature of approximately 800C. 3. Availability of substitutes 3.1 Alternative applications There are no known alternatives to PTFE used as an anti-drip agent in FR PC resins and blends for electrical applications that result in the same flammability, electrical, impact, weathering, and other properties and application performance. Alternative formulations/compositions would require potentially long-term re-testing of the material, and part re-design and requalification. Any alternative solution must first be technically feasible and meet regulatory requirements. It is then likely that in most cases the parts made from the alternative solution will either have a shorter lifetime/more waste (because of failures related to impact/ductility) or will be unable to meet other application requirements. In-service failures of parts also carry the risk of fire and electrical shock events. 3.2 Alternative substances Electrical device manufacturers must constantly balance meeting both safety standards and real-world performance requirements. While there are many thermoplastics available that can meet some of the requirements for electrical components like switches and circuit breakers, as listed in the Table 1 below, none of them have the balanced properties necessary to meet all the requirements for a given electrical device. In addition to fire and electrical safety requirements, key physical properties such as (low temperature) impact and ductility are important. Impact resistance is the material's inherent resistance to permanent deformation or breaking caused by a force acting upon it (e.g., a collision with another object, a drop, etc.). Ductility is a materials inherent ability to bend without breaking. During assembly, use and maintenance of electrical devices, components like switches and circuit breakers will be decoupled and re-coupled. They rely upon polycarbonate's inherent toughness in cold temperatures to ensure the devices do not break and rely on PTFE as an anti-drip additive to meet safety requirements. The PTFE is able to survive any environment in which the polycarbonate can be used. There are several ways to determine a material's impact resistance and ductility. Two common methods are Notched Izod Impact (NII) and Tensile Elongation (TE). These techniques measure the amount of energy that a material can absorb during impact or the amount of 3 Bakker, J., Bokkers, B., & Broekman, M. (2021). Per- and polyfluorinated substances in waste incinerator flue gases (RIVM Report 2021-0143). https://www.rivm.nl/bibliotheek/rapporten/2021-0143.pdf 9 Classification: General Business Use elongation (as a percentage of the initial gauge length) that a material will deform before breaking. These tests are performed in controlled laboratory settings, following standardized test methods such as ASTM D2564/ ISO 1805 for NII and ASTM D6396/ISO 5277 for TE. The higher the values in these tests, the tougher the material is and the more resistant it is to cracking or breaking. Polycarbonate and its blends are used prevalently in the electrical industry because of the unique balance of flame resistance and toughness they can provide. Table 1 shows a broad range of unfilled materials' flame resistance, as measured by their UL94 V-0 and 5VA/B ratings, along with their cold temperature impact retention and inherent toughness compared to an FR polycarbonate blend with PTFE as an anti-drip agent reference. Impact and ductility data is shown as a percentage decrease in Notched Izod Impact and Tensile Elongation. Material (non-reinforced) Property Comparison Property Flame Resistance Passes UL94 V-0 @ 1.2 mm / 5V-A/B @ 2.5 mm New Polycarbonate Blend w/ PTFE Anti-Drip Impact/Crack Resistance Notched Izod Impact, % of Reference 100% (Ref) PPE/PS 12% (88% decrease) Polyetherimide 4% (96% decrease) PPSU 83% (17% decrease) PEEK 11% (89% decrease) Polypropylene Copolymer FR, Talc Filled Polyamide FR, Glass Fiber Filled 13% (87% decrease) 11% (89% decrease) Ductility Impact/Crack Resistance Elongation @Break, % of Reference 100% (Ref) 14% (86% decrease) 55% (45% decrease) 55% (45% decrease) 46% (54% decrease) 12% (88% decrease) 2% (98% decrease) Cold Temperature Impact Retention T T T Table 1. Property comparisons of existing materials As can be seen in Table 1, several materials can achieve the necessary flame resistance. However, none of these materials have a comparable toughness to the FR PC blend with a PTFE anti-drip additive. The significantly lower ductility and toughness makes most of these materials unsuitable for use in applications that require inherent resistance to cracking and breaking, which are key requirements in the design and manufacturing of electrical components like switches and circuit breakers. 4 Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics (astm.org) 5 ISO 180:2019 - Plastics -- Determination of Izod impact strength 6 Standard Test Method for Tensile Properties of Plastics (astm.org) 7 ISO 527-1:2019 - Plastics -- Determination of tensile properties -- Part 1: General principles 10 Classification: General Business Use 4. Development of possible substitutes 4.1 Actions taken to develop alternative applications or alternative substances Owing to its unique physical property profile leading to exceptional performance as an antidrip additive (e.g., high heat resistance, excellent compatibility across a broad range of materials, chemically inert, fibrillation/deformation under shear, inherent resistance to ignition, efficacy at very low loadings), there are no known direct replacements for PTFE as an antidrip agent in FR PC resins and blends for electrical applications. FR PC resins and blends are often desired for their cold temperature impact strength. For these PC resins and blends, there are several strategies that can be employed to increase resistance to dripping by increasing melt strength or the stiffness of the material with either viscosity enhancers or mechanical fillers. For example, melt strength can be improved by incorporating compatible polymers to increase the zero-shear viscosity of the system (e.g., highly branched PC). Because this approach significantly increases the viscosity of the system, it does improve the system's resistance to deformation as the temperature increases. Similarly, glass fibre or other inorganic fillers (e.g., clay, talc, carbon fibre) can be added to increase the stiffness or modulus of the material. Table 2 shows the flame resistance, and the inherent toughness of formulations using these strategies as compared to a PTFE anti-drip additive. PTFE Replacement Property Comparison in PC Property PTFE Branched/High Viscosity Resin Mineral (Glass, Talc, Clay) Carbon Fiber Flame Resistance Passes UL94 V-0 @ 1.2 mm / 5V-B @ 2.5 mm T T Impact/Crack Resistance Notched Izod Impact, % of Reference 100% (Ref) 14% (86% decrease) 16% (84% decrease) 10% (90% decrease) Ductility Elongation @Break, % of Reference 100% (Ref) 44% (56% decrease) 6% (94% decrease) 1% (99% decrease) Table 2. Comparison of the flame resistance and ductility/toughness of various classes of PTFE anti-drip replacement options compared to a polycarbonate blend reference sample with a PTFE anti-drip additive. As can be seen by the property comparisons, these approaches have a significant effect on the impact resistance and ductility of the materials. Unlike PTFE, these additives must be used at relatively high loadings (10-50 times or more than PTFE loadings) to have a significant effect on anti-drip properties. These high loadings of fillers cause a dramatic decrease in the ductility 11 Classification: General Business Use and impact resistance of the material. This significant trade-off in properties makes them unsuitable for use in applications that require inherent resistance to cracking and breaking, which are prevalent requirements in the design and manufacturing of electrical devices. 4.2 Stages and timeframes needed to establish possible substitutes There are no alternatives to PTFE available today for use as anti-drip agents in FR polycarbonate resins and blends that result in the same extraordinary properties and application performance for switches and circuit breakers. A wide range of potential alternatives have already been tested and found to fail to provide the necessary properties. A new round of extensive, fundamental laboratory research will be needed to attempt to identify a completely new material, unknown today, that may potentially be developed into an alternative to PTFE. SHPP expects it may take up to 8 years to carry out this basic research. If a new alternative material is identified it would take several more years to test, qualify, certify, and start manufacturing parts from this replacement material. Companies may need to make changes to their manufacturing equipment and processes to use the new material in their moulding lines. These changes to manufacturing equipment and processes may be significant and require extensive time and capital investment. Product requalification is a very time-consuming exercise that will require extensive resources over many years. The completion of this task will require sufficient test house capacity and transition time to requalify all existing flame retardant PC resin and blend parts in products. For a company with a wide range of existing product designs, SHPP estimates it could take up to 5 years to carry out the necessary manufacturing equipment changes and product requalifications. 5. Request for derogation for use of PTFE as an Anti-Drip Additive in Flame Retardant Polycarbonate (FR PC) Resins and Blends for Electrical Components Given the two derogation choices, SHPP respectfully requests a 12-year derogation. Since there are no PTFE alternatives available which can provide the same performance functions and the same/better safety benefits, at least a 12-year derogation is absolutely needed. The material industry will need to develop a better solution (or equivalent) if possible, and all the moulders and OEMs from the electrical industry who use this type of material will need to re-design and re-test their parts, devices, and systems. Since the proposed derogation is only for PTFE, one additional point of reference is the UK's recently published PFAS regulation proposal. They limited their proposed restriction to certain and specific PFAS substances and did not apply the restrictions to an entire class of fluorine substances. Of particular note, they are excluding fluoroplastics and fluoroelastomers (such as 12 Classification: General Business Use PTFE, PVDF, etc.), which they consider as low hazard groups, from their proposed regulation. Presumably, this is because fluoropolymers (such as PTFE) are not water soluble, are not mobile, and do not present the same level of environmental hazards as low-molecular-weight non-polymeric PFAS. SHPP believes this also provides a basis for a total exemption of PTFE from the potential REACH restrictions if one is to be considered. 13