Goldilocks and the UV Curable PSAs

Lisa Castillo, KIWO and Jim Raymont, EIT, KIWO adhesives and EIT Instrument Markets

Abstract: From digital smartphones to medical devices, Pressure Sensitive Adhesives are an important and rapidly growing application for UV curing.

Unlike many UV applications where a “more is better” approach is sometimes embraced, overexposure to UV energy results in a loss of PSA performance properties. Thus, proper process control is important to achieving UV PSA success.

This presentation examines what happens to PSA performance with under- and over- cure process conditions. We review the most common factors that affect UV PSA curing including chemistry and formulation, proper selection and maintenance of UV light sources, and process conditions (e.g. line speed, distance to lamp) and some LED specific curing parameters.

We present some examples of PSA problems and suggest how they can be identified using proper UV measurement technique. This presentation is intended for both formulators of UV curable adhesives who wish to properly specify cure parameters for their materials and for end-users who wish to implement better process control in production.