Elastic floorings are usually provided with a thin coating of irreversibly crosslinked polyurethane (duroplastic PU coating), which is intended to protect the flooring against mechanical influences and soiling.

Abrasive substances and influences such as loose soil can lead to abrasion (scratches and surface abrasion) of duroplastic PU coatings. In areas of high stress, damage to duroplastic PU coating can occur after only a few months. Worn areas lead to a change in floor covering properties (e.g. optical appearance, slip resistance, soiling behaviour).

This is particularly the case with structured elastic floorings (embossed wear layer), as the wear layer is no longer sufficiently protected against mechanical influences.
Therefore a material removal of raised areas occurs, which leads to a significant change of the surface structure.

Currently, renovation of elastic floorings without surface structure is associated with high effort. It is therefore not economically feasible as a method for regular maintenance of elastic floorings by cleaning service providers. Elastic floorings with surface structure usually cannot be renovated.

Elastic floorings are currently being filmed with care dispersions at great expense in order to avoid renovation of PU coating.

Application of care coating can induce a change in floor covering properties, as it masks the surface of elastic floorings (change in material-specific properties). In case of structured surfaces, application of renewable care coatings also results in a change in surface structure.

A temperature-connective polyurethane (PU) coating was therefore developed within a joint research project of the Forschungsinstitut für Leder und Kunststoffbahnen and the wfk-Cleaning Technology Institute.

Such a temperature-connective PU coating enables an efficient renovation of elastic floorings: on the one hand, it is possible to renew them completely or partially, and on the other hand, it can be structured by means of embossing moulds. Embossing makes it possible to adjust properties relevant to the floor covering (e.g. optical appearance, slip resistance, soiling behavior) during manufacture and to maintain them during the service life by restructuring.

The temperature-connective PU coating is based on thermoplastic PUs with thermally switchable crosslinking functions as end groups (cooperative TPUs), which means that crosslinking state of the coating can be specifically regulated via temperature.

Due to the temperature-dependent crosslinking state of the temperature-connective PU coating, the PU coating is in a flowable or highly viscous state (partially crosslinked or non-crosslinked state) under application or restructuring conditions (elevated temperatures), whereas it is solid under service conditions (room temperature, fully crosslinked state).

High adhesion during use was achieved by specially developed temperature-connective wear layers of elastic floorings, which, due to functionalization of their surface with thermally switchable crosslinking functions, form reversible bonds to the temperature-connective PU coating.

The research report is available on request from FRT.