Study on Preparation and Performance of Reactive Polyurethane Hot Melt Adhesives Based on a Polycarbonate Diol and a Polyester Diol

Reactive polyurethane hot melt adhesives (HMPURs) containing a mixture of poly 1,3-propylene sebacate diols (PPSe) and poly 1,6-hexanediol carbonate diols (PHC) as soft segments were prepared to investigate the influence of the relative content of PHC and PPSe on the properties of the HMPURs. The results showed that the HMPURs had excellent thermal stability below 250 °C; when the temperature was above 250 °C but below 360 °C, the HMPURs prepared from PPSe or PHC had better thermal stability than the HMPURs prepared from the mixture. With the increase of PHC content, the melting viscosity and elongation at break (δ) of the HMPURs decreased, while the open time and bond strength of the adhesive on PC substrates increased. When the polycarbonate diol content in the soft segments was higher than 50%, the HMPURs had better hydrolysis resistance than when it was lower.