Shelf life and storage
Most Erapol brand prepolymers have a shelf life of at least 12 months from date of manufacture when stored, unopened, in their original containers at temperatures less than 25oC (77oF).
All Erapol products are packaged and sealed with a blanket of Nitrogen gas. When the container is opened and the Nitrogen is replaced with humid air, the isocyanate content of the prepolymer (% NCO) can drop due to a reaction of the moisture with the prepolymer. If the NCO drops too much the material can be damaged, which will result in poor physical properties in the finished product. Hence partial containers of prepolymer should be re-sealed with nitrogen or dry air to prevent moisture contamination.
Effects of Heating Pre-Polymers
The % NCO content of all prepolymers will decrease with time and especially with exposure to heat. The table below shows how much total time a typical prepolymer can take before it is degraded beyond repair: