Thermal insulation materials reduce heat transfers between surfaces or environments.
They work by limiting the conduction, convection, and radiation of heat, and are die-cut into specific shapes and sizes that can be wrapped around or installed between components such as pipes, panels, equipment, and enclosures.
We proudly work with these material partners
Converting Thermal Insulation Materials
At ISP, we buy thermal insulation from our material partners and convert these materials into products that arrive ready to install. We’re also equipped to work with proprietary customer-supplied materials. Depending on the part volumes that you need and required tolerances, we can use:
We can also help you choose the optimal thermal insulation materials for your application.
From prototyping through production, ISP can be an extension of your engineering team
To discuss your thermal management application, contact us online or call (800) 984-1811.
Learn More About Thermal Insulation Materials
What is Thermal Insulation?
Heat is the flow of thermal energy, which means it doesn’t stay still. Instead, it moves between surfaces or environments that have different temperatures. Heat always flows from a hotter object or area to a cooler one, but it can move in three different ways.
Conduction relies upon direct contact between two materials.
Convection uses fluids such as air or water to move heat.
Radiation transfers heat through electromagnetic waves.
Thermal insulation materials can reduce all three types of heat transfers. In this sense, they are the opposite of thermal interface materials (TIMs), which are designed to move thermal energy rather than impede its flow.
Technical Specifications for Die Cut Thermal Insulation
Die cut thermal insulation materials have several key technical specifications.
Types of Cellular Thermal Insulation Materials
ISP die cuts three main types of thermal insulation materials.
These materials contain air-filled cells that minimize heat transfer. Note, however, that silicone thermal insulation also includes solid materials with a non-cellular structure.
Cellular thermal insulation can have an open-cell or closed-cell structure.
- Open cells are interconnected and allow air and moisture to pass through the material.
- Closed cells are sealed and do not permit the passage of air or moisture.
The type of die cut thermal insulation to select depends upon your performance requirements and the application environment. For help with material selection, contact ISP.
Closed Cell EPDM Foam
Closed cell EPDM foam reduces heat transfer, resists water absorption, and withstands outdoor environments. Its closed cells contain trapped air, which is an effective thermal insulator.
Air’s thermal conductivity varies with temperature and pressure but is generally listed as 0.01 W/mK. EPDM rubber has a higher thermal conductivity (TC), but it’s still relatively low at 0.29 W/mK. The low thermal conductivity of closed cell EPDM foam isn’t the only reason to use it for heat insulation, however.
Closed cell EPDM foam provides excellent resistance to water, moisture, and humidity. That’s important for thermal insulation because water has a TC of 0.6 W/m/K at 20°C – which is significantly higher than either air or EPDM.
Applications for closed cell EPDM foam include HVAC systems, refrigeration units, buildings, and vehicles. Among its advantages, this type of die cut thermal insulation conforms to irregular surfaces without air gaps. It is also durable and resists exposure to sunlight, ozone, and temperature fluctuations. Flame-rated formulations are available.
Polyimide Foam
Polyimide foam is a thermal insulation material that is inherently fire resistant. It is also lightweight, chemically resistant, and acoustically insulating. As a thermal insulator, polyimide foam maintains its structural integrity and performance properties at temperatures up to 300°C. By contrast, most closed-cell EPDM foams cannot withstand temperatures higher than 100°C.
Polyimide foams can have either an open-cell or closed-cell structure.
- Open-cell polyimide foams are softer and have lower tensile strength. Because they are more compressible, they are suitable for applications that also require cushioning or sound absorption.
- Closed-cell polyimide foams are rigid but come in different densities. Generally, they provide more effective thermal insulation than open-cell materials. They can also be used as the core or middle layer in sandwich-style heat insulation.
Regardless of its cellular structure, polyimide foam provides excellent chemical resistance and retains its material properties even after prolonged exposure to solvents, fuels and oils, and some acids and bases. Strong acids and bases can cause polyimide foams to degrade, however. Polyimide foam is also UV-resistant.
Polyimide foam is used in aircraft and spacecraft because it’s lightweight, resists fire, and protects against extreme temperatures during flight and re-entry. Low outgassing versions are available for the low-vacuum environment of space. With its strong combination of thermal and acoustic insulation properties, polyimide foam is also used aboard trains and ships and with processing equipment.
Silicone Thermal Insulation
Silicone thermal insulation is available in cellular (foam and sponge) and solid formulations.
- Silicone foam can have an open-cell or closed-cell structure. It resists temperatures up to 200°C and has a lower tensile strength than silicone sponge or solid silicone rubber.
- Silicone sponge has a closed-cell structure and provides greater tensile strength and tear resistance than silicone foams. It resists temperatures up to 260°C.
- Solid silicone rubber has the highest tensile strength and the best high-temperature performance. It can withstand temperatures higher than 260°C.
All three choices leverage the advantages of silicones. Temperature resistance and thermal stability aren’t the only reasons to use silicones for die cut thermal insulation, however. These materials also resist moisture, humidity, and many chemicals while maintaining their flexibility.
Applications for silicone thermal insulation vary. For example, silicone sponge is better than silicone foam for rugged applications; however, solid silicone is even less likely to tear. Among its advantages, silicone resists sunlight and ozone. Flame resistant silicone thermal insulation is also available.
Advantages of Cellular Thermal Insulation Materials
Polymer-based cellular thermal insulation materials are not the only types of thermal insulation. Alternatives include:
- Fibrous insulation includes fiberglass, mineral wool (rock wool), and ceramic fiber. These materials contain tiny fibers that trap air.
- Reflective insulation includes materials such as aluminum foil, which reflects radiant heat and can be used in multi-layer structures such as heat shields.
- Natural and sustainable insulation includes biodegradable materials such as sheep wool, recycled cotton, and cork.
Compared to these other materials, cellular thermal insulation provides advantages in terms of moisture resistance, structural integrity and durability, and thermal performance.
- Moisture Resistance: Cellular insulation materials, especially those with closed-cell structures, prevent the ingress of water and resist the absorption of moisture.
- Structural Integrity and Durability: Cellular insulation materials maintain their shape over time. This reduces the need for frequent replacements of maintenance.
- Thermal Performance: Cellular insulation provides consistent thermal performance by minimizing heat transfers.
In addition, cellular thermal insulation is easier to handle than fibrous insulation and has more consistent material properties than natural and sustainable insulation.