Oil-bleeding silicone rubbers have a special property: they constantly exude small amounts of silicone oil. The oil droplets form a film on the surface of the elastomer that greatly improves the part's functionality and sealing action in several application areas. At Plastindia 2012, WACKER will present two oil-bleeding product series: ELASTOSIL® R plus 48xx and ELASTOSIL® LR 384x. ELASTOSIL® R plus 48xx is a one-part, solid silicone rubber with excellent mechanical properties. It features extremely high tear strength and elongation and is ideal for seals that must be especially cut resistant. Mat seals and cable bushing mats made from ELASTOSIL® R plus 48xx are so cut resistant that they are not damaged even when sharp-edged plugs are inserted.
ELASTOSIL® R plus 48xx is an addition-curing product and cures much faster than a peroxide-curing silicone. Consequently, production cycles can be shortened dramatically. ELASTOSIL® R plus 48xx can be injection molded. Thermal post-curing of the resultant elastomer imbues it with low, permanent compression set and therefore with good long-term sealing action.
Easy to process: ELASTOSIL® LR 384x
ELASTOSIL® LR 384x, too, is an oil-bleeding silicone elastomer. Unlike ELASTOSIL® R plus 48xx, ELASTOSIL® LR 384x is a liquid silicone rubber with a broad processing window. It tolerates fluctuating process parameters. Thus, perfectly molded parts are obtained even if process temperatures, pressures and injection profiles are not accurately maintained.
ELASTOSIL® LR 384x is available in different Shore hardness values, and oil contents of 1 to 6 percent. It is injection molded like standard liquid silicones. The end products do not require thermal post-curing as they achieve low, permanent compression set and thus provide good long-term sealing action without additional curing.
Flame-Resistant and Self-Extinguishing: ELASTOSIL® R 770
A further highlight at Plastindia will be ELASTOSIL® R 770. This silicone rubber cures to a flame-resistant, self-extinguishing elastomer. When it burns, it generates little smoke and emits no toxic fumes. ELASTOSIL® R 770 can be extruded and molded to products that combine typical silicone rubber properties with exceptional fire safety characteristics. The cured elastomer is heat stable and remains permanently elastic even at low temperatures of down to – 40 °C, without the need for a plasticizer.
ELASTOSIL® R 770 lends itself to the production of elastic molded parts, profiles, slabs, films and fabric-reinforced silicone sheets for use in railway cars, regional trains, aircraft, ships and buses. Typical applications include door, finger-guard and wall profiles for high-speed trains, bellows for connecting carriages in trains and articulated buses, and fire-proof, acoustic insulation mats for planes, trains and ships.
ELASTOSIL® R 770 meets French railway standard NFF 16-101, which is stricter than the German fire safety standard for rail vehicles (DIN 5510). Moreover, studies carried out in accordance with Ameri¬can standard UL 94 showed that these new solid silicone grades qualify for V-0 classification. Thus, they are also suitable for applications outside the transport sector.
GENIOPLAST® Pellet S – Manufacturing Additive for Thermoplastic Polymers
For makers of thermoplastic polymers, WACKER will be presenting GENIOPLAST® Pellet S at Plastindia 2012. This is a highly concentrated silicone additive in pellet form. Its active ingredient is a non-crosslinked, ultra-high-molecular, linear silicone polymer (silicone gum). The carrier material for the silicone is a pyrogenic silica which has been tailored for the silicone. Since this pyrogenic silica is compatible with all thermoplastics, the additive can be used to compound every type of thermoplastic – unlike conventional silicone masterbatches.
The additive is easy to meter and is readily incorporated, also along with any mineral fillers, into thermoplastics. The silicone active ingredient improves filler dispersion and its friction-lowering properties make compounding and shaping of the thermoplastics easier for the plastics converter. It also benefits injection molding by improving the flow properties of the thermoplastic melt. Should the molding compound alternatively be used for extrusion – e.g. to make cable sheaths – the additive will enhance the process and lower costs.
GENIOPLAST® Pellet S imparts a smoother surface to thermoplastic polymers. This means that it also enhances the scratch and abrasion resistance of the molded part. Adding GENIOPLAST® Pellet S to mineral-filled thermoplastics additionally boosts the notched impact strength and elongation at break. The product also acts in synergy with flame-retardant fillers. Key applications of GENIOPLAST® Pellet S include cable sheaths and molded parts for automotive interiors, such as dashboards and door panels.
Visit WACKER at Plastindia 2012, Booth E7, Hall 12
(Source: Wacker Press)