Preparation of Polyurethane Solid–Solid Phase-Change Material with Soft Segment for Application on Temperature-Regulating Fabrics

The emergence of water-borne polyurethane solid–solid phase-change materials (PCMs) has overcome the problems of core material leakage in solid–liquid phase-change materials. However, water-borne polyurethane solid–solid phase-change materials also have issues such as poor heat storage performance and limited temperature regulation range. This study used polycaprolactone diol (PCL-diol) and poly(ethylene glycol) (PEG) as the composite soft segments, and selected dicyclohexylmethane-4,4′-diisocyanate (HMDI) and glycerol (GL) as the hard segments, to prepare a PEG-PCL-HMDI PCM. By adjusting the ratio of the composite soft and hard segments, the content of the soft segment, and the molar ratio of the monomers, the phase-change temperature was precisely controlled and the heat storage performance was synergistically improved. After the PEG-PCL-HMDI PCM had finished being applied onto the surface of cotton fabric, the temperature-regulating fabric exhibited a significant temperature-buffering effect in the 25–35 °C human activity temperature range, with the heating rate reduced and the cooling rate delayed. This study provides a new material system and process scheme for the development of intelligent textiles with both efficient energy storage and precise temperature regulation functions.