How to Choose the Right High Temperature PSA Tapes for Your Bonding Application
High temperature bonding applications require specialized materials that can withstand everything this unique application environment throws at it. It’s no secret that high temperatures can have a substantial impact on pressure sensitive adhesive tapes. These effects cause certain tapes and bonds to fail if those tapes are not specifically designed to perform in a given temperature range. Choose the wrong pressure sensitive adhesive (PSA) tape and you will not see the best results.
What are the best high-temperature PSA tape options? Are there any other environmental conditions that you should consider before making your final choice? In this brief technical guide, we’ll delve into the intricacies of selecting the right high-temperature materials for your bonding application as well as the other environmental resistances you’ll need to account for based on your application’s requirements.
How High Temperatures Impact Pressure Sensitive Adhesive Tapes
Heat is energy. When absorbed by a material, the material’s atoms and molecules will move more quickly and, in certain cases, the substance can undergo certain chemical changes. When heat is applied to PSA tapes, especially over long periods of time, many things can happen:
Adhesive softening: high temperatures cause adhesive tapes to soften, reducing their structural integrity and performance.
Reduction in adhesive and cohesive strength: A reduction in strength will impact the degree of force the PSA tapes can withstand under stress.
Accelerated aging: Heat accelerates the aging of PSA tapes. This can drastically decrease the lifespan of the bond or reduce its strength as time passes.
Material expansion: on a chemical level, as molecules move faster, they will take up more space. This causes materials to expand when exposed to high temperatures. This can impact the dimensional stability of PSA tapes and compromise the quality of the bond.
Wet out speed: as temperatures rise, wet out will happen more quickly and should improve adhesive anchorage once the PSA returns to room temperature..
Obviously, the type of PSA, how high the temperature reaches, and its duration determine whether these factors are a non-issue or cause lasting damage to your application.
Other Factors to Consider in High Temperature Applications
Every application is unique, which is why there is no single PSA tape option for high temperature environments. Depending on what you are trying to bond, there can be many other environmental challenges that you have to consider. Different PSA tapes will have strengths and weaknesses depending on the other environmental requirements your application has, including:
Exposure to UV light, humidity, and moisture
Electrostatic Discharge (ESD): consider the protections your tape needs to provide. Learn more about EMI/RFI shielding here.
Exposure to oils, grease, chemicals, and other solvents, which can degrade certain types of materials.
Dynamic and/or static loads: consider the forces acting on your bonds. These can include shear, tensile, cleavage, and peel forces.
Are Single-Sided, Double-Sided, or Adhesive Transfer Tapes Better for High Temperature Applications?
There are high-temperature PSA tape options available in single sided, double sided, and adhesive transfer tape variations, allowing you to choose an adhesive tape option that fulfills your needs.
Single-sided PSA tapes have an adhesive applied to only one side of the backing material. They are ideal for environmental sealing applications on doors and windows and are known for their cost efficiency, conformability, and easy application. Since nearly any high temperature film, like Kapton or PTFE, can be combined with any PSA adhesive, these tapes can provide excellent temperature resistance.
Double-sided PSA tapes have adhesive applied to both sides of the backing material, allowing for bonding between two similar or completely different surfaces. They are versatile and ideal for a wide variety of applications, giving the added benefits of improved handling power, dimensional stability, and the ability to fill gaps. The addition of the carrier, however, often will impede the overall temperature resistance.
Adhesive transfer tapes consist of a thin adhesive layer coated on a release liner. They can be single-sided or used to bond two surfaces. They are ultra-thin and conformable, leaving a clean appearance, and offer some of the highest temperature resistances on the market.
The Difference Between High Temperatures Resistance and Insulation
High temperature resistance refers to a material's ability to withstand and endure elevated temperatures without significant degradation or loss of functionality. It allows the PSA tape to maintain its structural integrity, mechanical properties, and performance under conditions of high heat.
Insulation involves using materials that are designed to minimize heat transfer, providing a barrier against the transmission of heat. PSA tapes and insulating materials help maintain the temperature difference between two adjacent areas by reducing the flow of heat, either into or out of a specific space. If you are interested in thermal insulation materials, these are some of your options.
Keep in mind the temperature range of your current application and which materials can provide the best resistance and/or insulation required.
High Temperature PSA Tape Options
When choosing which style of PSA tape, make sure to consider its compatibility with the substrates you are bonding. Your high temperature PSA tape options include:
Silicone PSA tapes: silicone PSA tapes have some of the highest levels of temperature resistance (often up to 500° F). They also offer high resistance to oxidation and ultraviolet (UV) light, excellent flame resistance, and high resilience to mechanical fatigue. However, these PSA tapes are not the most cost efficient and can have limited uses. They bond best to silicone substrates.
Acrylic PSA tapes: acrylic PSA tapes are the most widely versatile and most used adhesive tapes because of their long list of resistances and ability to bond to nearly any substrate. Acrylic double coated PSA tapes can resist temperatures of up to 350° F, making them suitable for some high temperature applications. On the other hand, acrylic adhesive transfer tapes (like 3M™ Ultra high temperature adhesive transfer tape) utilize a high performance and low outgassing adhesive system having excellent heat resistance in high temperature environments. They are also resistant to chemicals and will give you a high holding power after their initial application period (which builds strength over 72 hours). These PSA tapes have some very high temperature resistance (up to 550° F), giving you a strong bond in the hottest environments.