“What is the service life of safety shoes? And why does the sole disintegrate after a certain period of time?”

Many users ask these questions. Different materials in the shoe have different service lives. A shoe consists of various components, some of them being subject to natural decay at some point. This is often dependent on the chemical composition of a material. This composition can produce certain properties, but it can also be the reason why the material has a certain useful life. The material that is responsible for the service life of the majority of our shoes is the polyurethane in the midsole and outsole.

Complaints and, in some cases, alleged quality defects generally reach us via our Marketing / Quality department. Where these concern specific issues, our experts perform a more detailed analysis in order to identify the cause of the problem. They produce a detailed response based on their findings.

My sole is falling apart!
We have even received complaints before where shoe soles have fallen apart immediately, despite infrequent use. The statements made by the users of these shoes were often fairly similar: the shoes were worn extremely rarely and were in fact only stored in the cardboard box for a long period of time. The users had either taken the shoes shown in the photos out of the box in this state, or they had fallen apart straightaway while wearing them.

You should also know that the shoes shown are no longer the latest models. The age of the shoes from their date of manufacture ranges between at least two years and a maximum of five years.

Why do shoe soles disintegrate?
Some of you have no doubt got shoes in your wardrobe of a similar age which are still good to wear. The reason for this is the aforementioned polyurethane (PU) sole material. PU is frequently used in safety shoes as it offers several positive properties such as very light, very flexible, very good shock-absorbing properties, highly abrasion-resistant, and good anti-slip properties.

All of this has a very beneficial effect on the user’s natural movement patterns and when it comes to the product life of the sole as regards mechanical influences. The specific composition of PU produces these material qualities, but it also affects the service life of the material.

Above all, the PU sole material is subject to a natural ageing process – hydrolysis.

What happens when soles age?
PU consists of long polymer chains that are gradually split apart due to the effect of moisture. As a consequence, PU loses flexibility over time and gradually becomes brittle. As the shoes reach an advanced age, this can lead to signs of disintegration in the soles.

But why can storing shoes often be more detrimental to their useful life than if they are worn?
Work shoes are often stored in the basement, shed or garage – places where poor sunlight & higher levels of moisture are normally present. And it is precisely this moisture that amplifies the hydrolysis process and causes the shoes to age even more quickly, even though they are not actually being worn.

Recommendations for you and your safety shoes
Ageing of safety shoes is an entirely normal process that all shoes go through. If we want to benefit from all the positive properties of a safety shoe, we need to be aware of the limited product life of shoes. We recommend adoption of “First-In-First-Out” during storing & distribution, regular use by user. Due to long storage, the shoe sole gets weak & loses its properties & does not last long. Further information can be found in the maintenance tips leaflet that comes with every Warrior Safety Shoe.

For details, visit www.warrior.co.in