JEC COMPOSITES MAGAZINE - Issue #40 - May 2008 - 61

with metals and inorganic materials. Wacker researchers match the functional group to the polymer to ensure optimum bonding between the two (figure 3). More information The Wacker Group is a globally-active chemical company headquartered in Munich, Germany. In 2006, the Group generated sales of €3.34 billion, according to IFRS. As of December 31, 2006, Wacker had reached a total of 14,700 employees. The Wacker Silicones division is a world-leading silicones manufacturer. Its portfolio ranges from silicone fluids, emulsions, resins, elastomers and sealants to silanes and pyrogenic silicas. These products find applications in such sectors as construction, chemicals, cosmetics, textiles, automotive, paper and electronics. More impact resistant than granite Fig. 3: Silane chemistry GENIOSIL® CS 2 is a methacry-licfunctional alkoxysilane. As a bifunctional, unsaturated organic compound, it can be incorporated into organic polymers by free radical addition, where it acts as a molecular bridge between inorganic and organic substrates. Wacker ships its silanes to major composite stone manufacturers in Italy, Spain, Turkey and Israel, among others. They blend the base compound, which may consist of quartz, polymer or silanes, and then fill large rubber moulds. On production lines, often in a fully automated process, the compound in the moulds is cured at approximately 100°C under vacuum to form slabs up to four square metres in size and several centimetres thick. They are then cut to size and polished to a gleaming finish. After that, they are shipped all around the world. The particularly high filler loading (up to 94%) of the high-end stone slabs represents a major challenge for “stone experts” of the Mediterranean and requires particularly sophisticated manufacturing technology. The added resin compound contains between one and two percent silanes. Presently, Wacker is also working on release agents that will help the finished stone slabs to slip out of their “rubber suits.” But there is also an environmental dimension to the use of Geniosil® silanes in composite stone: it is more dirt-repellent than its natural counterpart. Ultimately, it cuts down on costs. Moreover, composite stone is much more resistant to alkalis and acids than marble, which means it can keep its polished finish for 10 to 15 years. Composite stone is also ideal for creating an air of grandeur for the pillars and walls of hotel lobbies and modern wellness facilities. Its appearance can be customized during production by adding colorants, special effect pigments, or tiny pieces of glass or mirror to create an exotic look. Composite stone is also popular with interior designers because the colours and marbling are perfectly reproducible. This means that a damaged section can easily be replaced with new stone identical to the original. Tab.1: Typical composite stone formulation d: density and df: average fibre diameter. > 90% < 5% 2% (based on resin) 0.2% (based on resin) 1% (based on resin) minerals (inorganic) unsaturated polyester resin peroxide initiator co-accelerator silane coupling agent, such as GENIOSIL® CS 2 Focus Organo-functional silanes are hybrid compounds that combine organic and inorganic groups in a single molecule. They are important ingredients in paints, coatings, adhesives, and sealants, in which they function as coupling and cross-linking agents. Silanes are also used to reinforce plastics with fillers and glass fibres. The Geniosil® silane formulation is so effective that many other industries are also interested in composite stone (see also Table 1). Kitchen specialists have discovered that it is the ideal alternative to granite and natural marble. After all, composite stone is eminently suitable for worktops and cladding: it is lightweight and has excellent mechanical properties. Some types of composite stone are even more impact-resistant than granite. The slabs can be imbued with antibacterial or antistatic properties and extreme thermal stability, making them ideal for coping with the hard knocks of a busy kitchen. More information: www.wacker.com No40 May 2008 / JEC Composites Magazine

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JEC COMPOSITES MAGAZINE - Issue #40 - May 2008

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #40 - May 2008