High Temperature Silicone Adhesive Sealant

High Temperature Silicone Adhesive Sealant

High temperature silicone adhesive sealant is a liquid form of glue that looks and acts like a gel. It is different from other more organic polymer-based adhesive types because it resists chemical corrosion and keeps its elasticity in both high and low temperatures.

Acetoxy cure silicones cure faster but don’t stick as well to surfaces as neutral cure silicones. Isothermal TGA results after heat exposure show a steep drop in modulus for both PU and bonding silicones.

Pressure Sensitive Adhesives

Pressure sensitive adhesives are a group of binders that require only light pressure to adhere to surfaces. They don’t need water, solvents or heat activation to exert strong adhesion forces and shouldn’t change phases (from liquid to solid) during use.

These binders are available for different substrates, including rubber, acrylic and silicone. Choosing the right type depends on an application’s requirements, such as heat tolerance or moisture resistance. Some PSAs are even designed for medical applications such as absorbent foam wound dressings, ulcer island dressings and multiple contact layers for negative pressure wound therapy.

Many industrial applications need high-performance adhesives, especially when working with etch PTFE. Master Bond offers a line of silicone PSAs that are ideal for such jobs. For example, our MasterSil 151Med is non-corrosive, optically clear and USP Class VI compliant for medical applications and biocompatibility. It is also thermally conductive and electrically insulative.

Other popular products include our MasterSil 711 silicone system. Its acetic cure formulation resists mildew and is ideal for use in sanitary areas like bathrooms, kitchens, laundries and showers. This non-corrosive system is also suitable for use in humid and warm environments. Its tack and set times are fast and the sealant remains elastic after curing. It’s suited for pump and compressor gaskets, appliance door and humidifier gaskets, ductwork and insulating wire and cable.

Silica

Silicone is a liquid form of adhesive that looks and feels like a gel. It has a different chemical makeup than more organic polymer-based types of adhesives, making it highly resistant to chemicals and moisture, as well as high and low temperatures.

A high temperature silicone sealant can be used to bind surfaces together, such as a gasket or adhesive in an engine or car, to keep high temperature silicone adhesive sealant it sealed under constant vibration and heat. It can also be used to bond and seal materials that are exposed to the sun or weathering, such as insulating wire and cables or sealing ductwork or furnace doors.

You can find RTV silicone sealants in a variety of colors and sizes to match your needs. Some have special ingredients that allow them to withstand even higher temperatures. For example, one formula can withstand 650degF for continuous exposure, which is ideal for aviation applications, such as bonding the lights on the exterior of airplanes.

To choose the right type of silicone, consider the highest and lowest temperatures the area will be subjected to. Then, decide whether you need it to be water-resistant or not, if it will need to be flexible, or if you need it to hold weight. Once you know the characteristics of your application, make a list of the specific properties you need and start shopping.

LED Curing

In the curing process, a liquid is exposed to wavelength specific UV light that initiates a chemical reaction that hardens the material. LED systems are more electrically efficient and produce less heat than broad-spectrum curing lamps, lowering energy costs. LEDs also require no warm-up time, enabling production to start immediately boosting productivity. Because of the lower temperatures, LEDs enable effective thermal management and minimize the risk of damage to heat sensitive substrates.

Unlike traditional bulbs, UV LEDs don’t degrade over time, maintaining consistent UV output throughout their lifetime. This allows manufacturers to reduce overall process variation, improve control and increase yield rates. In addition, the long lifetime and instant on/off control of UV LEDs allow them to be used with heat-sensitive applications, such as encapsulation and sealing of copper, brass, steel and aluminium components in electronic assembly.

For these reasons, LED curing is a sustainable option for printing and coating applications. LEDs are solid-state semiconductor devices, which emit UV energy through a photochemical reaction in a diode. The specific materials in the diode determine the wavelengths of the emission, with current generation LEDs having peak emission in the UV range around 365 nm and 395 nm. When properly matched with the formulations and photoinitiators, LEDs deliver a wide range of quality, productivity and operational benefits to print customers.

Temperature

Silicones exhibit a low glass transition temperature, resulting in the ability to withstand high temperatures for extended periods of time. This capability makes them ideal for sealing and bonding in a high temperature silicone adhesive sealant wide range of industrial applications. High-temperature silicones are also often used in automotive applications, as they can withstand the intense heat of engine parts and components.

When selecting a high-temperature silicone sealant, it is important to consider the desired application and expected exposure. For example, acid-cure silicones can corrode metal and etch some plastics, so they are generally not suitable for use on contact areas of mechanical systems. Neutral-cure silicones are generally safer to use on most materials, including metals.

In addition to considering the desired temperature, it is also important to select a high-temperature silicone that will maintain its physical properties after prolonged exposure to extreme temperatures. This is especially critical for applications in buildings and other structures, where fire resistance is a crucial consideration.

One of the ways to evaluate the performance of a silicone adhesive is to subject it to a tensile stress-strain test under varying temperature conditions. This will determine how much the elastic modulus, elongation and stiffness change with temperature. For this study, Momentive Performance Materials evaluated two structural silicone rubber adhesive sealants. Both the silicones retained 75% of their original mechanical properties after heat ageing (2 h at 180°C). This represents an acceptable level of loss for the types of applications typically found in rooms isolated from, but adjacent to, fires.