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How to Make Polyurethane Dispersions

Polyurethane dispersions (PUD) are high cost formulations used in a variety of applications and industries such as adhesive resins. Typically, PUDs were made using a solvent-based method, which caused issues with volatile organic substance release and other hazards. Polyurethane is not water soluble so an emulsion or dispersion of the polymer is necessary. An emulsion is a solution containing fine particles that do not fall out of solution and impart chemical properties to the solution. The preferred method of production is a water-based procedure that uses acetone.

Things You'll Need

Dry polyurethane particles
500 mL glass beaker
Acetone
Emulsifier blender
Diethanolamine (or similar diamine)
Monoethanolamine (or similar monoamine)
Laboratory vacuum distillation unit

Instructions

- 1
  Add the dry polyurethane particles into the glass beaker and add approximately 250 mL of acetone. Insert the emulsifier blender into the beaker and blend for thirty minutes.
- 2
  Add the diethanolamine to the blender and continue to blend for 5 minutes. Add only approximately 10 mL of the amine. This will thicken the solution. If, after 5 minutes, the solution has not thickened, add another 10 mL and continue blending.
- 3
  Add an identical volume of monoethanolamine to the beaker and blend for 5 minutes. This will keep the urethane from further extending and causing the mixture to solidify.
- 4
  Distill any remaining acetone using the vacuum distillation unit. Run the unit at 100 degrees F for 30 minutes. Once complete, the polyurethane can be added to water to create a stable emulsion.

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