High-content organosilicon waterborne polyurethane and its application in fabric pigment printing

O rgano si licon w aterborne p olyurethane (OSi-WPU) has gained great attention for its improved water resistance and thermal stability, offering great improvement over conventional two-component WPUs. These improvements are primarily achieved by incorporating organosilicon (OSi) into the PU matrix. However, existing methods such as physical blending or chemical grafting show limitations of poor compatibility and modest reaction efficiency, resulting in uneven distribution and limited silicon (Si) content. Here, we develop an advanced OSi-WPU formulation with up to 2.52 wt% silicon doping along the PU molecular chain, showcasing outstanding water resistance (with water absorption rate reduction by 37.5 % compared to pure PU), enhanced thermal stability (marked by an enhanced glass transition temperature), and good film-forming capability (remarkable smoothness and evenness). The core of our innovative approach lies in the chemical bonding of a carboxylic acid-functionalized polyol and a liner polyol-functionalized Si-segment, synthesized via a Michael addition reaction between unsaturated 2,3-dihydroxypropyl acrylate and γ-aminopropyltriethoxysilane, to the hard segments of the PU prepolymer through urethane linkage, which ensures a high silicon content and uniform distribution throughout the PU structure. Additionally, when this OSi-WPU is blended with various pigments (including red, green, and blank) and applied to fabric substrates, it not only maintains exceptional smoothness and evenness in film-forming properties, but also significantly enhances the abrasion resistance of virous pigments. Our methodological advancement lays a robust foundation for future enhancements in WPU technology.