Pressure-sensitive adhesives (PSAs) are used in applications ranging from labeling food packaging to assembling electronic devices to mounting graphics displays. Although they have been around for decades and their use is widespread, manufacturers, converters, and printers may not understand the key differences between the adhesive choices available, how they’re constructed, or which are best suited for a particular job.
 
  This article explains what a PSA is, how it’s constructed and what adhesive options are available. The advantages and disadvantages of the primary adhesive types will be addressed, as well as how they are formulated and their common applications.
 
 
  What is a PSA?
  A pressure-sensitive adhesive is a material that holds two surfaces together solely by surface contact, which is achieved by slight initial external pressure. These dry adhesives require no activation with water, solvent or heat, and firmly adhere to many dissimilar surfaces with minimal pressure. Aggressive and permanently tacky at room temperature, PSAs can be used for bonding materials such as plastic, paper, metal, glass, and wood.
 
  Pressure-sensitive adhesives offer numerous advantages. Application can be easily automated and usually requires no elaborate equipment. When used in assembly, PSAs save time compared to liquid adhesives because they don’t require any setup or long curing times. In addition, adhesion is immediate, allowing manufacturing procedures to continue uninterrupted, which results in significant time and labor savings. Pressure-sensitive adhesives eliminate the need for screws, rivets, clips or drilling holes, thus preventing cracks and corrosion and improving the integrity and appearance of the final product. PSAs also provide an insulating seal, as well as sound and vibration control.