Futuristic outlook for silicones

Published: April 28, 2017

At the company’s Annual Meeting in March 2017, Dr Christoph Kowitz, Vice President Performance Silicones at WACKER SILICONES, explained how silicones have become an indispensable part of everyday life. Peter Walter, Senior Marketing Manager Industrial Solutions, then provided a fascinating insight into silicones in tomorrow’s automotive industry, and their roles in the evolution of e-mobility, autonomous driving and connectivity.

Dr Christoph Kowitz, Vice President Performance Silicones, began by explaining that the term ‘silicone’ was coined by the English chemist FS Kipping (1863-1949), who derived it from the chemical names ‘silicon’ and ‘ketone’. Kipping wanted to point out the analogy between the oxygen compounds of silicon and those of carbon. However, it is more accurate to use the term ‘siloxane’ for the typical molecular structure of silicones. Siloxanes are the elementary building blocks of the polymerization products (e.g. polysiloxanes or polyorganosiloxanes) used to make silicones.

Silicones are part semi-inorganic silicate and part organic polymer. Dr Kowitz explained that because of this hybrid nature, silicones possess properties in a variety and range shown by no other polymer. Through controlled modifications of the molecular structure, it is even possible to create unprecedented individual property profiles. Indeed, since they were commercialized in the mid-1950s, silicones have become an indispensable part of everyday life. The Global Silicones Council (GSC) estimates that, globally, silicone applications add €36 billion of industrial value.

For example, silicones protect automotive electrics against moisture and dust. As additives for auto paints, they provide gloss effects. In washing machines, silicone antifoam agents prevent the detergent from foaming over. In shampoos, silicones provide the hair with a satin gloss, while making textiles fluffy and soft. Silicone resins protect house walls against moisture while being permeable to allow water vapour and CO2to escape from the interior. Silicone elastomers have sealant and adhesive properties, and are extremely elastic. High-purity silicone gels and silicone rubbers are used for wound care, in clinical applications and for orthopaedic products.

WACKER is the second-largest silicone manufacturer in the world (after US specialty chemicals group Dow Corning). In 2016, the WACKER SILICONES business division achieved €2 billion in sales (37% of total group sales) with 3,000 different products. A crucial factor in this success and in the division’s cost position is WACKER SILICONES’ unique integrated production system. The Group is among the few world-ranking silicone manufacturers to perform all the required process and value-creation steps at its integrated sites – starting with the manufacture of crude silane and siloxane, through to the finished end products.

WACKER has been developing silicone products for the industry for over seven decades. Perhaps one of the most exciting applications – one that would grab most of our imaginations – is the futuristic use of silicones in the automotive industry. WACKER SILICONES is well established in the automotive industry, with about 60 years of experience in this sector. However, while proud of this history, WACKER definitely has its sights on the future.

“The future of mobility, the experts agree, will be electric,” said Peter Walter, Senior Marketing Manager Industrial Solutions. Although 95% of cars still run on fossil fuels, the growth of the electric car market is rapid. In 2016, there were already 1.3 million electric vehicles worldwide, 73% more than in 2015. Their sales are being further stimulated by tax incentives and increasingly stringent CO2 limits. By 2030, it is anticipated that every second new car, at most, will be electrically powered.

In order to conserve resources and to further reduce climate-damaging emissions, the automotive industry is replacing more and more mechanically operated parts with electrically-powered counterparts. Automotive electronics are becoming increasingly important. A ‘mid-range’ vehicle nowadays contains as many as 100 electronic control units. Advanced Driver Assistance Systems (ADAS) are providing an unprecedented level of comfort and safety. Furthermore, thanks to ever-more sophisticated electronics and sensors, autonomous and self-driving cars are already on the way to reality. Progress is also being made in digitalization.

The car of the future will be connected to the internet via numerous touchscreens and optical displays and will become a communications centre on wheels!

Silicones from WACKER play an indispensable role in all this. They are used in many different ways in manufacturing and assembly of electronics. Heat-resistant silicone elastomers, for example, protect sensors and electronic components from dirt and moisture. After curing, they must seal the sensitive and safety relevant chips permanently. Often, the sealed components are oven-cured to speed up processing – a laborious, costly process. New silicone adhesives from WACKER build up adhesion at moderate temperatures, making this additional processing step dispensable. Special UV-activated catalysts from WACKER can shorten processing times even more.

The performance, range and charging times of electric vehicles need to be increased substantially if electromobility is to prevail in the long term. The outcome of this will be increased power density and higher electrical and thermal loads. This will also affect the potting materials used in electric cars, e.g. for power electronics. Silicones are the material of choice here on account of their extreme heat resistance. Special silicone potting compounds from WACKER can withstand continuous thermal stress beyond 200oC without embrittlement. Specialty silicones that can withstand even higher temperatures are already under development.

Heat is generated during both driving and charging, and this can adversely affect the life of the battery and electronics. Therefore, the heat needs to be dissipated as quickly as possible if damage is to be prevented. Silicones are contributing to efficient thermal management. They serve as thermally conductive gap fillers that provide a conformal, flexible connection between component and heat sink, thus minimizing interfacial thermal resistance. WACKER’s highly thermally conductive gap fillers quickly dissipate the heat and contribute to the component’s effective cooling.

Enormous progress is also being made in the digitalization of vehicles and connectivity with the internet. The number of optical displays in the cockpit is set to increase further, as a result. Increasingly, the traditional dashboard is being replaced by its fully electronic counterpart with in-built monitor and communications system. Numerous displays will provide the driver, front-seat passenger and rear passengers with access to all kinds of ‘info-tainment’ devices and internet services.

Such displays, however, will need to be much more rugged than ordinary handheld displays. Vibrations and jolts must not cause them to fail. And they must work just as well at -40oC as they do in the summer heat. Good readability is particularly important. The driver must be able to read the information on the display perfectly at night and in sunshine. WACKER supplies crystal-clear silicone gels which ensure that optical displays meet these requirements. They dampen vibrations and thermomechanical stresses and at the same time suppress interfering reflections between the cover glass and the display.

Electromobility, digitalization, autonomous driving – the car is being reinvented. Many of the materials which have been used in cars up to now are struggling to meet ever stricter requirements. For this reason, the industry is increasingly turning toward silicones. Possible applications now range from potting compounds for sealing connectors and fuel cells, coatings for electric motors, liquid silicone rubbers for LEDs and light-guide systems through to battery-cooling fluids. WACKER is working around the world on this with leading auto makers and their suppliers to develop reliable solutions for the cars of the future.


Copyright © 2017 Mack Brooks Speciality Publishing.