Pressure-sensitive adhesive fundamentals

A pressure-sensitive adhesive (PSA) is a substance capable of holding materials together by instantaneous low-pressure surface contact. Most commonly, a PSA is based on selected elastomers modified to enhance tackifying and wetting properties.

These products require no activation by water, solvent or heat to exert a strong holding force on varied materials that include paper, plastic, wood, cement and metal. They have enough cohesive holding power and elasticity so they can be handled and removed from surfaces without leaving a residue.

Hot-melt PSAs are adhesives that are applied to a backing in hot liquid form, then cooled to form a conventional pressure-sensitive adhesive. These products are commonly used in tapes and labels.

  • Hot-melt PSA (HMPSA) – a PSA applied as a 100% solids, thermoplastic composition in the molten state
  • Water-based PSA (WBPSA) – a PSA applied in aqueous emulsion form and dried to form the adhesive film
  • Solvent-based PSA (SBPSA) – a PSA applied in solvent solution form and dried to form the adhesive film
  • Calendered PSA – a PSA applied as a 100% solids composition in a calendering operation