A preliminary approach for blooming removal in polyurethane-coated fabrics

Coated fabrics with thermoplastic polyurethane (TPU) are largely found in fashion and design collections in imitation leathers and glossy-look fabrics. Unfortunately, blooming is a common damage in aged TPU, appearing as white crystalline deposits at the surface. These deposits have been generally identified as adipic acid and mainly affect ester-based aromatic TPU. The white colour of adipic acid often leads to the complete unrecognition of the cultural item, highly decreasing its values. Strategies to remove blooming are still absent in the literature, resulting in a lack of action by conservators. The Glossy Surfaces project addressed this issue through preliminary research on cleaning strategies to remove adipic acid. Dry and wet methods were tested on two fabrics showing blooming and different surface cohesion. Non-confined and confined liquids in hydrogels were included and assessed by digital microscopy, colourimetry, and infrared spectroscopy. The best results were achieved with agar-agar, but limitations were also recognized.