panel_PUR_adhesive

PUR Glue

PUR (reactive polyurethane) hot melts are a more recent development for perfect binding and are largely different from the EVA and SBR (styrene butadiene rubber) hot melts. They polymerize when applied so that they form much stronger bonds than traditional hot melts. They also possess superior flexibility and can withstand a larger range of temperatures. They are currently much more expensive than traditional EVA hot melts (2-4X) but application rates are much lower. PUR is clear, less of it needed to create a solid bond and it yields stunningly beautiful products. Hot Melt Adhesives are an excellent choice when bonding difficult substrates when immediate tack is needed.

Physical Properties of PUR Glue

  • The major limitations for hot melts are the suspect nature of hot melt bonds at temperatures over 150° F due to its thermoplasticity and safety issues due to the high temperatures used.
  • PUR glue requires a 24-hour curing period. During this time, PUR books must remain exposed to natural air because the bonding chemicals in PUR cure by drawing moisture out of thin air.

The Major Advantages of PUR Glues

  • PUR glues are excellent for tacking tough adhesive binding jobs
  • Excellent immediate (green) tack
  • Quick achievement of final bond strength
  • Great adhesion to many surfaces
  • Excellent shelf life
  • Great flexibility
  • Lay flat friendliness