Published On: Sat, May 25th, 2013

WACKER Develops Modular System for Pourable Silicone Rubbers

Munich, May 24, 2013–WACKER, the Munich-based chemical Group, has developed a modular system for pourable, additioncuring silicone rubber compounds. With this system, available under the ELASTOSIL® VARIO name, both the reactivity of the silicone rubber compound and the hardness of the elastomer can be adjusted as desired. Compounders and silicone processors can now produce tailor-made products in any desired quantity. ELASTOSIL® VARIO is suitable for encapsulating and coating, for making technical molded parts, and for mold making.

WACKER Develops Modular System for Pourable Silicone Rubbers

WACKER Develops Modular System for Pourable Silicone Rubbers

ELASTOSIL® VARIO falls into the category of addition-curing RTV-2 silicone rubber compounds. These consist of two components that enter into an addition reaction with each other at room temperature in the presence of a platinum catalyst. The ELASTOSIL® VARIO system consists of four modules: two different base components and two different catalyst components. The two base components can be blended together in any ratio, and so can the two catalysts.

From these modules, the processor mixes the two components of the RTV-2 silicone rubber compound in the quantities needed for curing. The mixing ratios for the base components and for the catalysts can be varied to match the silicone rubber system to the intended application. Accordingly, processors can produce tailored RTV-2 silicone compounds just the way they need them. Such flexibility from only four system modules is unparalleled.

The mixing ratio for the two catalysts determines how reactive the system is and how fast the rubber cures. For instance, the pot life can be set to any value ranging from a few minutes to far in excess of two hours. Curing times range from 15 minutes to 7 hours. The hardness of the cured rubber is determined by the ratio in which the two base components are mixed, with attainable durometer hardness values spanning 15 to 40 Shore A. Irrespective of the mixing ratio for the base components, the tensile and tear strengths of the cured rubber remain consistently high.

Typical applications of ELASTOSIL® VARIO are encapsulation of electronic devices and circuits and coating of technical textiles and metal or plastic surfaces. The modular system also lends itself to the production of gaskets and of silicone mold parts, such as those used for making prototypes in medical technology. It can also be used to make all kinds of reproductions and molds. ELASTOSIL® VARIO is translucent and can be pigmented in any color. The two self-mixed components can be processed in pressureless casting systems,either by hand or with the aid of two-component mixing and metering lines.

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