Polyurethane Material Properties

What is Instant Set Polymer?

Instant Set Polymer (ISP) is a solid polyurethane material developed in the mid-1970’s.  It takes its name from the fact that it is created by mixing two liquid components which react to form a solid material in less than a minute!  In order to process this fast-reacting material, Intrepid uses the Reaction Injection Molding (RIM) process.

Through this unique chemistry and process, the material can be molded into thick-section parts (up to 4″ wall thickness).  The final product is rigid, tough, and strong with excellent fatigue resistance.  Being a plastic, it also has good electrical insulating properties and resists atmospheric corrosion.

ISP exhibits outstanding weatherability because it has a unique internal UV screen.  In addition, it is extremely easy to machine – it can be drilled, tapped, sawed, and shaped.  It has proven to be an excellent material choice for harsh environments where metal, wood, and ceramics get destroyed and must be replaced on a regular basis.  Molded parts can offer extended service life as well as result in more immediate cost savings by combining multiple parts.

The following is a summary of ISP’s typical physical properties. All tests were run in accordance with ASTM procedures.

Density 1.16 gm/ccElongation 15%
Flexural Modulus of Elasticity 280,000 psiHeat Distortion Temp. 190° F
Tensile Strength 8,000 psiIzod Impact 1.0 ft-lbs/in of notch
Compressive Strength 9,000 psiHardness 76 Shore D


  •   Excellent Outdoor Weatherability (Built-in UV Block)
  •   Good Electrical Insulating Properties
  •   Excellent Surface Reproduction
  •   Fatigue Resistant
  •   Provides Strong, Rigid, Thick-Section Parts (1/4″ up to 4″ thick)
  •   Outstanding Compressive Strength
  •   Will Not Rust, Corrode or Degrade
  •   Can Be Machined, Drilled, Sawed and Shaped

View the QUV Accelerated Weathering Test Data