Chemical Technology May 2016

Numerous properties of precision silicone films make them particularly interesting for the industry. Not only are they ex- tremely elastic, they also do not wear out. Tests have shown that Elastosil ® Film can survive over 10 million load cycles without the slightest fatigue. Silicone films hold back water but grant free passage to water vapour and certain gases. This gas permeability is highly selective: carbon dioxide, oxygen and water vapour pass through the silicone layer much faster than nitrogen. Elastosil ® Film could therefore serve as a membrane for removing a specific gas, such as carbon dioxide. Experts expect that, over the coming years, relays, switches and valves based on dielectric electroactive elastomers will come onto the market. Such components could, in the future, also give rise to new technologies, such as shape-changing touchscreens that the visually impaired could read with their hands. In the healthcare industry, for example, WACKER’s Silpuran ® Film is breath- able, biocompatible and easy to sterilise. These silicone films are therefore ideal for the manufacture of soft and flexible wound dressings. Simulation with silicone For pressure-sensitive adhesive (PSA) labels to function properly, the release coatings, adhesives and backing materials must be optimally matched and must suit the industrial processing conditions. WACKER tests this out in its new Dehesive ® Coating Centre. Not all labels are the same. While product information should permanently adhere to a shampoo bottle, the price

label on a water melon must peel off easily. Different ad- hesive mixtures make specific applications of self-adhesive materials possible, but also present the coatings industry with the challenge of providing a constant stream of new, modified silicone formulations for release liners. In addition, the substrate itself and subsequent process- ing play a role in deciding the composition of the release coating. For automated dispensing of labels, for example, it is important that the paper lattice between the individual labels – the matrix – can be pulled off easily without tearing or removing the labels from the backing material as well. Testing and optimising At the new coating centre in Burghausen, engineers work on a 380 m ² area to simulate industrial processing condi- tions for silicone release coating and to devise coating solutions to meet various requirements. The new centre combines a pilot coater, a test lab and a large selection of base papers and films used in the industry. This makes it possible to simulate and evaluate industrial processing conditions for silicone release coatings as realistically as possible, allowing the company to prepare new products for the market more quickly. Dr Hans Lautenschlager, who is in charge of technical support for silicone release coatings at WACKER, and his team are currently testing formulations for seven different substrates supplied by a US partner. There is a choice of 30 silicone polymers and five crosslinking agents available for the coating. Depending on their composition, the individual formulations vary with regard to flow properties, release force and curing rate. Dehesive ® silicone release coatings have been used in the paper coatings industry for many years to make self- adhesive materials that separate perfectly from release The requirements imposed on PSA labels vary considerably depending on the intended application and production method. Consequently, demands on the silicone release coating are high.

The mechanism for removing the adhesive from the silicone release coating forms the basis of tailor-made solutions.

Dr Robert Gnann took over as president of WACKER SILICONES, effective April 1, 2016. He succeeded Dr Christian Hartel, who was appointed to the WACKER Group’s Executive Board in early November 2015. Gnann comes to WACKER from Momentive Performance Materials, where, from 2008, he was responsible for the elastomers business unit and, in 2010, additionally took charge of the company’s European activities.

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Chemical Technology • May 2016