Pressure sensitive adhesives (PSA) are used in many different applications with new uses being discovered almost daily. PSA use will continue to grow as a solution to fastening and joining due to advances in adhesive technology, ease of use, and its low cost compared to traditional fastening systems. The following is meant to give you the basics of adhesives and things to consider when determining the best adhesive for your application.
What is Pressure Sensitive Adhesive?
Pressure sensitive adhesive (PSA, self adhesive, self stick adhesive) is a relatively thin flexible adhesive either single or double side coated. PSA will adhere to a variety of substrates when applied to most clean and dry surfaces with pressure. Pressure Sensitive adhesives do not require solvent, water, or heat to activate the adhesive. The bond is directly influenced by the amount of pressure which is used to apply the adhesive to the surface.
The Advantages of Pressure Sensitive Adhesives
- Thinner and lighter materials
- Bonds dissimilar materials without incompatibility concerns
- Provides vibration dampening and noise reduction
- Reduces assembly time
- Eliminates the need for surface refinishing
- Eliminates visible mechanical fasteners for cosmetic superiority
- Provides uniform thickness and gap filling properties
Typical Adhesive Types
Rubber: Adhesives which are based on natural or synthetic rubbers and formulated with tackifying resins, oils and anti-oxidants. Rubber is the most cost effective PSA and offers quick stick capability. Rubber adhesive is not recommended for high heat applications.
Acrylic: Adhesives formulated with acrylic polymers and generally has a better long term aging and more resistance to solvents and environmental factors. Acrylic adhesives typically develop a stronger bond than the traditional Rubber adhesive and are able to take higher temperatures
Silicone: Formulated with Silicone polymers and the only adhesive that will bond well with silicone substrates. Silicone adhesives are relatively expensive and have a very low initial tack, but can withstand higher temperatures than both Rubber and Acrylic adhesive.
|Temp. Resistance||Low||High||Very High|
|Low-surface energy materials||Excellent||Poor/Moderate||Poor|
|High-surface energy materials||Excellent||Excellent||Moderate|
Typical Pressure Sensitive Tape Constructions
Single Coated: An adhesive coated on one side of a material (Facestock). The adhesive is protected by a silicone coated release liner.
Transfer Tape: An unsupported mass of adhesive film coated on a release liner which has a release coat on both sides. Transfer tapes offer good conformability to irregular surfaces.
Double Coated: A carrier is coated on both sides with PSA. The adhesive carrier can be a wide variety of materials including plastic films, tissue, nonwovens, etc. Typical uses include laminates and carpet tape.
Self Wound: A carrier which is coated on one side with PSA and on the other with a release coating. There is no release liner with these types of products. Carton sealing, Duct and Masking are all examples of self wound tapes.
Things to Consider in Making the Proper Product Choice
- What is the material/substrate the adhesive will be sticking to?
- What are the conditions the tape will be exposed to, Temperature, Moisture, UV, Chemicals?
- What is the function of the PSA?
- How will the PSA be applied?
- Is it a permanent or temporary application?