There is a secret to creating ultra-comfortable safety footwear. For years, that secret has been Polyurethane(PU). Polyurethane is an organic compound that is created by combining an isocyanate with a polyol (an organic compound containing multiple Hydroxyl groups).
This creates a compound that provides the stability of a hard rubber, but with much much more cushioning. But Polyurethane has a weakness, hydrolysis.
Hydrolysis is the chemical breakdown of polyurethane on the molecular level, caused by an incursion of water molecules (to put it simply, this process gets complex quick). The good news is that this process does not generally happen very quickly, it won’t happen because your boots get wet while you are working. This process happens very slowly over time, we’re talking years. The bad news, it’s inevitable. If your footwear has PU in the sole, it will eventually break down, splitting and crumbling.
Fresh out of the box
For most people, this actually won’t make a huge difference in their footwear, running shoes and work boots tend to see their useful lifespan well before this can occur. So why is this a problem with workboots especially? The answer is that people often get workboots every year and don't change them out apporpriately, or they wear them seldomly. A good example of this is an office worker who only occasionally needs to wear their shoes to enter a plant or job site. This person may only need to purchase footwear every few years. Because hydrolysis occurs from just the water vapor in the air, footwear that is sitting under a desk or in a closet for many years will slowly start to degrade.
Hydrolysis has taken hold of this shoe after 13 years in storage.
Manufactured August 2005.
So, what’s the solution? Well, the best answer we have been able to find is simply to wear your footwear. Hydrolysis tends to set in faster on footwear that is stored in a dark enclosed space where water vapor has trouble escaping. Generally, when we see footwear that has succumbed to this, it is a pair that sat in storage for several years and started to crumble as soon as the owner tried to wear them. If you have some shoes in storage, check them out, and get those boot into your rotation, it’s better for you and your boots to not wear the same pair everyday anyway!