Room-Temperature-Vulcanizing Silicone Rubber (RTV-1/RTV-2)
Room-temperature-vulcanizing (RTV) silicone rubber compounds are a traditional core competence of WACKER. The range of ready-to-use products focuses on numerous applications in the fields of bonding, sealing, potting, encapsulation, coating and casting.
Equally broad is WACKER’s experience in processing techniques and material requirements specific to these applications, from DIY-scale right up to industrial production lines.
Important Applications of RTV Silicone Rubbers
Benefits of RTV Silicone Rubbers:
- Excellent thermal resistance
- Outstanding long-term thermal stability from -50 °C to +180 °C
- Constant properties over a wide range of temperatures and frequencies
- Outstanding dielectric properties
- Excellent release properties
- Very good adhesion to a variety of substrates
- Superior weathering, UV and radiation resistance
- High chemical purity and biocompatibility
- Low Young’s modulus
- Long-lasting flexibility
- Selective gas permeability
- Water-repellent surface and low moisture uptake
- Very good chemical resistance
- Chemical inertness
- Excellent environmental compatibility and no harmful effects
- Excellent physiological tolerance
- Flame resistance
One-part room temperature vulcanizing silicones (RTV-1) are ready-to-use systems consisting of polysiloxane, curing agent, fillers and additives. Right after application, the material starts crosslinking on contact with moisture in the air. Byproducts are released during curing. Crosslinking starts with the formation of a skin on the rubber surface and gradually progresses into the compound. Depending on the nature of the crosslinker, a small amount of acetic acid, amine or neutral byproducts, such as alcohol, is released during vulcanization.
RTV-1 silicones are ideal for almost all sealing, bonding and coating applications, such as:
- Electrical engineering
- Health care
- Textile sectors
- Household appliances
Two-part room temperature vulcanizing silicones (RTV-2) are pourable, spreadable or kneadable formulations that vulcanize after mixing. There are two different types of crosslinking reactions: by condensation or by addition. Condensation curing requires an organotin catalyst and always releases byproducts. Addition curing requires a platinum catalyst and does not generate any byproduct.
Special RTV-2 silicone rubber grades can be flash vulcanized using UV light. The vulcanization time can be controlled by adjusting the UV intensity and exposure time.
Like RTV-1 silicones, RTV-2 formulations are ideal for almost all sealing, bonding and coating applications. They are used for:
- Mold making
- Household appliances
- Health-care applications
- Mechanical engineering
- Industrial process engineering
- Lighting technology
- Solar / photovoltaics
Silicone gels are characterized by a particularly low crosslinking density and produce very soft vulcanisates below the Shore hardness range. They are suitable for various applications in industries such as:
- Transmission and distribution
- Health and wound care
Specific gels such as low-temperature flexible gels and fluorinated materials were developed especially for the automotive industry. They exert only minimal stress on encapsulated components exposed to temperature fluctuations.
Silicone foam formulations are characterized by high crosslinker content, namely, an SiH-rich polysiloxane. Its basic function is to crosslink the liquid formulation and release hydrogen, which acts as a blowing agent as curing progresses. Silicone elastomer foams are typically used in applications such as:
- Lightweight construction
- Thermal insulation
- Fire safety