How do rubber tiles change over time?
Rubber tiles made from PU-bound rubber granulate change over time in colour and surface appearance. The extent depends on the type of granulate, the amount of sunlight at the installation site and the level of use. Elastic properties generally change more slowly than appearance.
During the first few weeks, the tiles go through a settling-in period. On coloured ELT tiles the pigmented PU binder can initially darken slightly in sunlight, and the surface may look temporarily uneven because individual tiles receive different amounts of light. A freshly cut EPDM wear layer can take on a slightly warmer tone during its first few days of sun exposure. The overall appearance usually becomes more even afterwards.
Over time, the cause of visible change varies with the granulate. Natural black ELT rubber granulate is deep black when new and gradually takes on an anthracite tone through UV exposure, much like a car tyre. In coloured ELT tiles, pigmented PU binder coats the black rubber granules, so the colour lies in the coating rather than throughout each granule. On areas subject to foot traffic, use can wear away this coating and expose the black granulate. For coloured ELT, wear through use, rather than UV exposure or weather, is the main cause of longer term colour change. An EPDM wear layer is coloured throughout, colour-stable and UV-resistant.
Deposits also change the appearance. Dust, pollen and fine sand can collect in the surface texture and make the area appear duller. These residues can be removed, while the surface retains its slip resistance. Tiles made entirely of ELT rubber granulate behave differently. Under prolonged, intense sunlight they can gradually lose some elasticity and become more brittle near the surface. This process develops more slowly than the visible changes in colour.