Anti-smudge and self-cleaning characteristics of waterborne polyurethane coating and its construction

A novel anti-smudge coating, based on waterborne polyurethane (WPU), Polydimethylsiloxane (PDMS) and Hexamethoxymethylmelamine (HMMM) was constructed. Specifically, hydroxyl capped WPU emulsions grafted with PDMS (WPU-g-PDMS_X) were prepared firstly, then the Hexamethoxymethylmelamine (HMMM) was used as the crosslinking agent to block the polar hydrophilic hydroxyl groups and the carboxyl groups in WPU-g-PDMS_X and increase the cross-linking density of the coating. Oily markers, water, hexadecane, fingerprint liquid, and common liquids in life (milk, coffee, ink and cooking oil) were utilized to demonstrate the anti-graffiti and self-cleaning characteristics of coatings. Aside from having great transparency and exceptional resistance to liquid corrosion, the coating still retains its anti-smudge capabilities even when bent or impacted, and they also exhibit 5B adhesion and 5H pencil hardness. This work provides novel idea and strategy for the preparation of WPU anti-smudge coatings.