Dielectric Properties for Digitalization, Electro Mobility and Autonomous Driving

Global consumption of fluoroplastics has continued to increase in recent years as consumer industries and applications in the chemical, automotive, electrical/electronics and semiconductor industries have developed strongly. Since these plastics also play a central role in current and future megatrends such as digitalization, e-mobility and renewable energies, a further positive development is expected.

Corrosion-resistant linings for pipes and vessels in chemical process technology continue to be an important market for PTFE in Western Europe

Corrosion-resistant linings for pipes and vessels in chemical process technology continue to be an important market for PTFE in Western Europe

(© SGL Carbon)

In fluoropolymers, the hydrogen atoms of the main carbon chains are completely or partially replaced by fluorine atoms. The most important common features of all fluorine-containing polymers are their almost universal chemical resistance, high UV and weather resistance and good dielectric properties. They also have a low friction coefficient, low adhesion and very good tribological properties with high wear resistance. In addition, they are incombustible and suitable for very low to very high operating temperatures.

Since the discovery of PTFE in 1938, fluoroplastics have proven themselves in numerous industrial processes and everyday applications. Applications range from fuel and media lines, seals, sliding elements, sensors in machine, vehicle and aircraft construction, linings, universal hoses, coatings in the chemical and pharmaceutical industries, medical technology, cable sheathing and semiconductor production for electrical engineering and electronics to consumer products such as non-stick seals in cookware. They are also used in the textile industry, e.g. for breathable membranes for functional clothing, as additives and in architecture, e.g. as dirt-repellent coatings and membranes for roof constructions.

Fig. 1. Worldwide consumption of fluoroplastics in 2018 by type

(sources: Fluoropolymers, IHS Markit; Recent Challenges in Fluoropolymer Business, FPS GmbH)

Fig. 2. Largest buyers of PTFE 2018 by region

(sources: Fluoropolymers, IHS Markit)

Table 1. Worldwide consumption of fluoroplastics in 2018 by country

(sources: Fluoropolymers, IHS Markit)

Worldwide Consumption Continues to Rise

In 2018, 320.3kt of fluoroplastics were consumed worldwide (Table 1). By comparison, global consumption in 2015 was 270 kt. This corresponds to an increase of 18.6 % over this period. The largest consumer of fluoroplastics in 2018 was China with 1 20kt, followed by the USA, Western Europe and Japan. In view of current megatrends such as electro mobility, renewable energies and digitalization, studies assume that the consumption of fluoroplastics will continue to increase by 4 to 4.5% annually until 2023 [1]. 

The most important representative of fluoroplastics is still polytetrafluoroethylene (PTFE), which accounts for 53% (171.2kt) of total consumption (Fig.l). In second and third place followed the melt processable polyvinylidene fluoride (PVDF) with 16% (50.6 kt) and fluoroethylene propylene (FEP) with 10% (30.7 kt) [1].
In terms of quantity, ethylene-tetrafluoroethylene (ETFE) is in fourth place with a consumption of 6.5kt in 2018. This is followed by perfluoroalkoxy (PFA) and polyvinylfluoride (PVF) [2].

Fig. 3. Production capacities of the six most important fluoroplastics manufacturers represented worldwide as well as the Chinese Shangdong Dongye Group

(sources: Fluoropolymers, IHS Markit)

China Leads in Consumption of PTFE and PVDF

The largest consumer of PTFE in 2018 was China with 69.3kt or 40.5% the second largest customer was Western Europe followed by the USA and Japan (Fig.2) [1]. In Western Europe, Germany, with its strong automotive and chemical industries, and Italy, with its domestic appliance and compounding industries, were the largest consumers of PTFE (37% and 28% respectively of total consumption). The largest demand in Western Europe, broken down by industry, came from chemical process technology (41 %), followed by mechanical and plant engineering (19%), the electrical/electronics industry (16%) and the automotive industry (9%) [1].

In the USA, Western Europe and Japan, the markets for PTFE the general processing industries, for coatings and linings for consumer and industrial goods, in the electrical and electronics industry and for cable sheathing are considered almost saturated. Only low growth rates between 1.3% (Western Europe) and 2.1 % (USA) can be expected here, while China is forecast to grow by 6.5% annually until 2023. Overall, global demand for PTFE is expected to increase by 4.1 % per year during this period. This means that this type will remain the most important representative of fluoroplastics in the future [1].

In 2018, China was also the largest consumer of PVDF (24.3 kt), ahead of the USA (1 2.4kt) and Western Europe (10.8 kt). The most important drivers for further market development are architectural coatings (especially in China) and new applications such as lithium-ion batteries, photovoltaic modules, water filtration systems and special films for architectural and automotive glazing. Demand for PVDF is therefore expected to increase significantly over the next five years. For example, an annual growth rate of 4.8% is forecast for melt-processable fluoro plastics (except PTFE) by 2023 [1].

Rising Production Capacities

The worldwide production volume of fluoroplastics in 2018 was 31 6kt. In terms of market share, production integration, geographical presence and breadth of the product portfolio, The Chemours Company, USA, is currently regarded as the largest manufacturer. Other leading suppliers with two or more worldwide production sites are AGC Inc. in Japan (formerly the Asahi Glass Company), Arkema in France, Daikin Industries Ltd. in Japan, 3M/Dyneon in Germany and Solvay SA in Belgium (Fig. 3). In addition, there is the Chinese Shandong Dongye Group, Ltd. which owns the world’s largest production plant for PTFE [l].

Fig. 4. For printed circuit boards with high transfer rates the Resin Coated Copper Foil (RCC) made of copper or other metals was coated with a 5 urn thick layer of Fluon+ EA-2000

(© AGC)

These seven companies owned 60% of the global production capacity for fluoroplastics in 2018. To meet the steadily increasing demand for fluoroplastics, the companies have taken numerous steps in recent years [l]. AGC, the world’s largest producer of ETFE, is planning further capacity expansions in the coming years. For 2019 a significant expansion of capacities for the special grade Fluon+ EA-2000, which is mainly used in the semiconductor industry, is planned. Arkema expanded its PVDF capacity in the USA by 20% in 201 8, after almost doubling its production in China to 12kt in 2014. Further expansion is planned for 2022. By the end of 2018, Chemours had expanded its production capacity for PFA at its Parkersburg site by 25%. The company even plans to double its PFA capacity by 2021.

In September 2014, Daikin commissioned a new production facility for FEP with a capacity of 6kt/a in Changshu, China. In future, the company intends to focus more on the development of fluoroplastics for the semiconductor industry and plans to expand its capacities in Kashima and Settsu by 2022. At the beginning of 2015, Dyneon commissioned its pilot plant for the recycling of PTFE at the Gendorf site in Germany, which, with a capacity of 500t/a, is currently the largest of its kind. Solvay plans to increase production capacity for its Solef PVDF grades by 35% by the end of 201 9. The Shandong Dongye Group, currently operates the world’s largest PTFE production plant with a capacity of 45kt/a (as of 2018). Over the next five years, the company plans to invest further in fluoroplastics, including the elimination of bottienecks in PTFE, FEP, PVDF and PFA.

Fig. 5. Functional fluoropolymers impart high temperature and chemical resistance to thermoplastic composites

(© AGC)

Fig. 6. New developments now make 3D printing of complex structures

(© AGC)

New Products and Markets

The current megatrends of mobility, neoecology, connectivity and digitalization present new challenges and applications for fluoroplastics. In recent years, the automotive industry has been characterized above all by ever stricter exhaust emission standards and limits, downsizing of engines while simultaneously increasing performance, reducing vehicle weight and lowering production costs. Typical applications for fluoroplastics include fuel and media lines, seals, sliding elements and the sheathing of cables and sensors, as they withstand very low to very high temperatures in the engine compartment, aggressive liquids and fuels, moisture, vibrations and high pressures.

Current trends such as e-mobility and autonomous driving as well as the ever- increasing proportion of electronic compo nents are making automotive systems more and more complex. Here, fluoroplastics can help to further improve the reliability and safety of products and components. Powerful rechargeable batteries for driving electric vehicles, for example, are among the new applications of PVDF. It can be used as a cathode and anode binder or for separator coatings, thus helping to extend the service life of rechargeable batteries. New on the market, for example, is Solvay’s Solef 5140, a PVDF with improved adhesion properties that is suitable as a binder for battery electrodes.

In order to improve the vehicle weight of hybrid or electric vehicles and increase the range, thin yet high-temperature resis tant cable sheaths are required. AGC’s new ETFE grade Fluon C88AXMP-HT has significantly better stress crack resistance and flexural fatigue strength than standard ETFE grades. In addition, it has very good abrasion resistance and mechanical strength, and due to the high flowability of the melt, it can be processed very well and at high extrusion speeds. It is suitable for cable cross-sections from 0.3 mm2 to 10mm2. The new Fluon+AR series from the same manufacturer is also based on ETFE. As a blend of ETFE and a special fluoroelastomer, these thermoplastic elastomers (TPE) combine the advantageous properties of a fluoroplastic such as high temperature and chemical resistance with very good flexibility. They can be processed using appropriate thermoplastic extrusion or injection molding processes and are suitable for sheathing cables and wires.

The broad field of power generation is another growth area for fluoroplastics. They are already used in numerous flue gas desulfurization applications in conventional coal-fired and waste-to-energy power plants. Due to their outstanding corrosion resistance to aggressive acids and other substances produced during the combustion of fossil fuels or various waste compositions, they ensure longterm trouble-free plant availability. In addition, they have high thermal shock resistance and acceptable heat transfer properties.

In the solar industry, thin films of ETFE can replace the protective glazing of conventional photovoltaic modules. Because they have a lower refractive index than iron-free glass, they help to increase the efficiency, reliability and economy of solar modules by providing excellent UV, moisture and weather resistance and reducing their weight. In addition, due to their flexibility, they can be applied for flexible modules or modules with curved surfaces. In fuel cell technology, fluoroplastics are used as ion exchange membranes, electrode coatings and gas diffusion layers.

New developments in the field of electrical engineering/electronics and telecommunications offer a wide range of applications for fluoroplastics, e.g. for sheathing cables and wires or in semicon ductor production. This segment alone recorded growth of around 8.5% in 2018 [3]. Modern transport and communication systems such as autonomous driving, e-mobility and 5G cellular technology require a new level of reliability and security in data transmission. Chemours Teflon fluoroplastic foam (FFR) grades are based on a patented foaming process and combine low electromagnetic attenuation, high dielectric strength, very high chemical resistance and inherent flame retardancy. They are used for sheathing data cables and meet the requirements of real-time data processing. Due to their low density and reduced insulation thicknesses, they also enable smaller and lighter components.

AGC offers the new Fluon+ EA-2000, a functionalized fluoropolymer that is particularly suitable for printed circuit boards with high data transfer rates or copper cladded laminates (CCC) (Fig.4). The adhesive properties of the product make it possible to produce very thin dielectric coatings on copper or other metals with very low surface roughness. This allows very high data transfer rates as required for future technologies such as the Internet of Things (IOT).

Trends and Challenges

In the field of composites, functionalized fluoropolymers offer chemical reactivity and improved compatibility with other materials and can contribute to the advancement of new developments. Examples are the modified fluoropolymers Fluon+ ETFE from AGC. These reactive high-performance polymers are ideally suited for new material combinations, polymer blends or composite and sandwich constructions. For example, thermoplastic composites with specific fluoropolymer properties can be produced which also have excellent fiber-matrix adhesion and thus good mechanical properties (Fig. 5).

In the field of processing, 3M has developed a new technology with which, for the first time, fully fluorinated polymers such as PTFE can be processed by means of 3D printing. The process, for which a patent has been applied, enables the production of components and the integration of several functions in one molded part – at the click of a mouse and completely tool-free
(Fig. 6).

The most important starting material for fluoroplastics is the globally occurring mineral fluorspar (fluorite), which, however, is mined on a larger scale in only a few countries. However, other products such as new refrigerants with reduced global warming potential, fire extinguishing agents or polyurethane (PU) spray insulation for buildings also make use of this resource. The increasing global demand for air conditioning and cooling is leading to a steadily rising demand for refrigerants and thus also fluorspar. Combined with the sustained growth of fluoroplastics, this has led to a shortage of supply in 2018, resulting in higher raw material prices and quotas in some cases. This makes the up-cycling of end-of-life products all the more important in the future. In 201 5 Dyneon opened the world’s first plant for the reconditioning of special fluoroplastics at its Burgkirchen site in Germany. Up to 500t of fluoropolymer waste per year can be reprocessed at the new plant and its starting materials recovered. In this way, large quantities of the raw material fluorspar and C02 emissions can be saved.

Claus-Peter Keller, Egelsbach, Germany