HTV Silicone Rubber Manufacturing HTV (High Temperature Vulcanizing) Silicone Rubber is a specialty synthetic elastomer which provides a unique balance of chemical and mechanical properties required by many of today's more demanding industrial applications. From its original development in the 1940's using a laboratory process to its final commercial form today, HTV Silicone Rubber gives exceptional performance in many different application areas. Manufacturing The Process begins with the reduction of silica (sand) to silicon metal which is then mechanically ground and reacted with methyl chloride at 300 degrees C into reactive methylchloro silanes which are fractionally distilled and separated into their mono, di, and tri counterparts. After distillation, the dimethyldichlorosilanes are hydrolyzed to form silanols from which linear Polymers are polymerized or polycondensed. These Silicone Polymers are relatively weak by itself and it is therefore necessary to reinforce the polymer by the addition of very fine, high surface area fillers (fumed silica. In addition, functional fluids called process aids are required as well as curing agents, which are needed for vulcanization. These so-called HTV Silicone Rubber-Bases are used by Silex to produce Tubes and Profiles. The Bases are mixed together with curing agents, pigments and additives according the required chemical and physical properties on a two-roll mill before brought into the extruder. Articles made from HTV Silicone Rubber show following interesting properties High temperature resistance up to 200 degrees C (stabilized up to 300 degrees C) Serviceability at temperatures from -60 to 200 degrees C Low Temperature flexibility -60 degrees C (Special grades down to -100 degrees C) Good elongation characteristics Excellent UV, Ozone and Corona resistance Good electrical insulating properties Conductive adjustable Good resistance to many chemicals Highly Translucent (easy to pigment) Physiological indifference Neutral smell and taste Low levels of smoke, no toxic by-products under fire conditions Easy to sterilize