Silicone rubbers are highly stable elastomers that are broadly used in industrial engineering and sealing applications. They are a viscoelastic class of synthetic polymers composed of silicone with added organic functional groups. Also known as polysiloxane, silicones comprise an alternating molecular chain of silicon (Si) and oxygen (O). They are inherently lubricating and chemically inert. Adding organic functional groups, such as carbon (C) and hydrogen (H), to a polysiloxane backbone enhances the thermomechanical properties of the polymer and forces it to adopt an elastomeric structure. Silicone rubbers can subsequently be used to form flexible, thermally-resistant, and chemically-stable coatings for a range of components.
One of the primary components manufactured using silicone rubbers is silicone-coated rope, which is designed as a high-temperature resistant sealant for numerous industrial applications. This blog post will explore the properties and applications of silicone-coated rope in more detail.
What is Silicone-Coated Rope?
Typically, silicone-coated ropes are engineered from electrical-grade fiberglass (E-Glass) textiles that are braided or knitted into diameters of no more than 2”. This flexible substrate is then entirely or partially coated with a silicone rubber compound to improve its thermomechanical properties.
Silicone-coated rope retains the chemical inertness of its polysiloxane backbone to mitigate the risk of cross-reactivity between the polymeric coating and process gases or fluids. They are engineered for non-combustibility, even in response to direct flame impingement and continuous upper use temperatures of approximately 260°C (500°F). Their flame-resistant behavior is coupled with non-wetting properties, making silicone-coated ropes suitably resistant to molten metal splashing.
Applications of Silicone-Coated Rope
Silicone-coated rope is typically used as a sealing solution for high-temperature components with extremely tight tolerances regarding airflow and emissions. Natural gas and biomass furnaces often utilize silicone-coated rope as the primary seal for doors and apertures, given their combined flexibility and high abrasion-resistant capabilities. They can eliminate smoke emission when furnaces are closed and provide long-lasting performance through multiple use cycles.
Thicker silicone-coated ropes, such as square-braided components, are broadly used as sealants for electrolysis cells in primary aluminum manufacturing.
Silicone-Coated Ropes from Mid-Mountain Materials, Inc.
Mid-Mountain Materials, Inc. specializes in the development of tailored insulation solutions for high-temperature applications. We engineer silicone-coated ropes using HYTEX® 1000 E-Glass yarns which boast a continuous upper use limit of 538°C (1000°F), and ample performance in short-term conditions of 815°C (1500°F). These are comprehensively resistant to compounds found in heat treatment applications and are impervious to various degradation phenomena such as rotting and thermal shrinkage. We elevate these properties with a functional coating of silicone rubber as required.