“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. This issue also plays an important role in the new versions of our instruction leaflets. We explain why shoes disintegrate and when you should buy new safety shoes.
Different materials in the show 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.
We have even received complaints before where shoe soles have fallen apart immediately, despite infrequent use.
The statements made by the wearers 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 wearers 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.

Footwear safety KWD805

Why do footwear safety soles disintegrate?

Safety shoes

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.
Polyurethane (PU) is frequently used in safety shoes as it offers several positive properties.
•Very light
•Very flexible
•Very good shock-absorbing properties
•Highly abrasion-resistant
•Good anti-slip properties

All of this has a very beneficial effect on the wearer’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.

Other sole materials are also subject to ageing processes. For example, the plasticisers contained in the rubber gradually diffuse out of the material. This also causes the soles to lose elasticity and become hard and brittle.
Ethylene vinyl acetate (EVA), which is well-known from the sports shoe industry, is not subject to hydrolysis, but it does present one disadvantage: it shrinks more quickly when exposed to constant loads like walking and running, and so it no longer returns to its original shape.
This is easily identifiable from the small “wrinkles” that the material obtains.