There is unfortunately some misinformation in the plastics world regarding weathering, exposure, and UV-resistance. In some cases where applications go wrong, customers simply did not consider how a certain plastic might handle being exposed to certain environmental factors. One of the largest pieces of misinformation is that reprocessed-black UHMW often called “UHMW black” is UV-stable. It is not; however, and has only some limited UV-resistance due to the addition of carbon black in the resin. The following are examples of weathering and exposure concerns for some popular plastics and options to mitigate these issues.
Nylon:
-Brittle in cold temperatures (below -15 degrees C)
-Absorbs water
Solution:
-Switch to acetal or Tuffkast
UHMW/Polyethylene:
-Poor UV-resistance makes it prone to cracking with UV-exposure
Solution:
-Procure a fully UV-stable grade
Polyurethane:
-Certain varieties weaken and break down in wet environments (hydrolysis)
Solution:
-Work with a plastics expert to select a polyurethane variety not weakened by hydrolysis
Polycarbonate:
-Poor weathering resistance, will yellow and crack with exposure
-Poor scratch resistance and tends to become cloudy with small marks when used in outdoor applications
Solution:
-Request sheets with UV stable and/or scratch-resistant masking. These will be typically unstocked.
For assistance with your application please contact us today.