Silicones: All-rounders for healthcare, electronics and climate protection
Silicones: All-rounders for healthcare, electronics and climate protection
Interview with Christian Gimber, Vice President Engineering Silicones, WACKER SILICONES, Wacker Chemie AG
Exclusively for K-MAG
Two-component electrical single-wire seals made of a thermoplastic and a self-adhesive liquid silicone rubber. WACKER offers both oil-bleeding silicone rubbers and those with a dry, slippery surface. Both product classes are easy to assemble. Photo: WACKER
Baby pacifiers, plug seals, medical tubing – we encounter silicones in a wide variety of life situations. Why? They are flexible, water-repellent, heat- and chemical-resistant and even have electrical properties. In short, they are true all-rounders! WACKER, the German chemical group and K exhibitor from the very beginning, is considered a European pioneer in silicones.
Christian Gimber, Vice President Engineering Silicones, WACKER SILICONES, Wacker Chemie AG. Photo: WACKER
In an interview with K-MAG, Christian Gimber talks about the unique properties of silicones, as well as where they are used and how they can contribute to climate protection.
Mr. Gimber, what are the distinguishing features of silicones? What properties set them apart from other plastics?
Christian Gimber: Silicones are among the most versatile plastics we know. The term does not actually describe a product, but rather a group of very different substances that all have one thing in common: They are based on an extremely stable molecular bond between the elements silicon and oxygen. This basic structure can be modified and supplemented almost at will – including, incidentally, with organic components – which explains the enormous versatility of silicones. This starts with the variety of products: silicones are available, for example, in the form of resins, oils, emulsions or rubbers. WACKER alone produces over 2,800 different silicone products. At K, the focus is traditionally on our silicone rubbers and silicone additives.
Silicone rubbers differ from other rubbers in their distinctive property profile. Of particular interest are those properties that result from the polymer structure and the formulation with crosslinkers and fillers. Silicone rubber is free-flowing before processing, and crosslinking transforms it into a rubber-elastic state that can be very easily modified. Silicone elastomers have, for example, excellent mechanical and electrical properties, are resistant to heat, chemicals and UV radiation, and are even suitable for applications in highly sensitive medical areas.
Silicones are therefore among the high-performance materials among elastomers. They are true all-rounders that offer significant added value thanks to their individually adjustable property profile and their diverse processing characteristics.
Hybrid cables made of ELASTOSIL® R plus 4305 silicone rubber. The automotive industry needs extrudable materials that reliably fulfill their electrical insulation properties over a wide temperature range and for a long time. Photo: WACKER
Where are they used?
Gimber: If I wanted to answer your question in one sentence, I would say: everywhere. There is now hardly an industry or sector in which silicone rubbers are not used, whether in the automotive industry, medical technology, consumer electronics or aerospace.
In some applications, the advantages are particularly obvious, for example in the healthcare sector. Medical hoses, seals or valves are often made of silicone because they are particularly pure, do not react with blood or other substances and can be easily sterilized. Silicones are also biocompatible and skin-friendly, which is why they are also used for babycare products or for wound care. Another example that illustrates the benefits of silicones very well is electromobility. Hybrid cables, connector seals, potting compounds for on-board electronics, thermally conductive sealants and fillers for cooling the drive battery – every electric car today contains almost twice as much silicone as vehicles with internal combustion engines.
Thermally conductive silicone gels are very well suited as gap fillers. Their task is to efficiently dissipate the waste heat of electronic components to the heat sink. Photo: WACKER
What special or innovative solutions do you offer at WACKER?
Gimber: WACKER focuses primarily on high-quality silicone specialties for innovative, technically demanding and sustainable applications. One example: composite components with self-adhesive silicone elastomers are difficult to assemble because of their high sliding friction. We have therefore developed liquid silicone rubbers that have an assembly-friendly, intrinsically slippery surface. Until now, such an effect was only possible with oil-bleeding grades, but these cannot be used everywhere. Thanks to our new development, silicone composite components can now also be used in the food industry, in medical technology or even in the automotive industry.
Seals made of liquid silicone rubber. Photo: WACKER
What trends do you currently see in the field?
Gimber: One topic is high-volume production. Many processors are under enormous cost pressure. The possibility of fully automated, cost-efficient production in large series is therefore becoming an increasingly important argument for many. Silicone rubbers have excellent processing properties and can be modified very easily, which is why they are the material of choice in many areas of application.
Another trend is non post-cure liquid silicone rubbers. Such products contain fewer volatile components and exhibit very good mechanical properties even without thermal post-treatment. Customer feedback shows that such products are increasingly in demand. WACKER has also reduced the proportion of volatile components in all liquid and solid silicone rubber products. In this way, we are setting new standards worldwide. Silicone processors can be sure that, with such products, they will continue to meet regulatory requirements and the demands of industrial and end customers in the future.
To what extent can silicones contribute to greater sustainability or climate protection?
Gimber: Silicones are enablers: they are among the most important enablers of climate protection. I would even go so far as to say that without silicones we would have a hard time achieving our climate targets. Silicones are used in many key industries and have become indispensable for the development of innovative, sustainable technologies. This applies to wind power and photovoltaics, where silicones seal and protect parts and components, as well as to electromobility, consumer electronics and building and window insulation.
Ultrathin precision silicone films are used, among other things, for fuel cells and for novel electroactive actuators and generators. Photo: WACKER
The European silicone association CES has calculated that the greenhouse gas savings from the use of silicones are many times higher than the amount of CO2 produced in the manufacture and disposal of silicone products. There are several reasons for this: For example, silicones are extremely heat-resistant, enabling compact and energy-efficient engine designs. Silicones also insulate electrical components, protect and cool electronic components, and ensure non-reflective displays. Our ultra-thin precision silicone films are also used for fuel cells and for novel electroactive actuators and generators that can also be used for power generation. The list of applications could go on and on. Silicone rubbers offer exactly what is needed to develop the innovative and sustainable products and technologies of tomorrow.
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