Synthesis and properties of reactive polyurethane hot melt adhesive based on a novel phosphorus-nitrogen-containing polyol

A novel phosphorus-nitrogen-contaning polyol (BHAPE) was synthesized from formaldehyde solution, 2, 2'-iminodiethanol and diethly phosphite by typical Kabachnik-Fields reaction. Reactive polyurethane hot melt adhesives with hydrolysis resistance and enhanced flame retardant properties (HMPURs) were prepared from poly (1, 4-butylene adipate), poly (carbonate diol), poly (tetramethylene ether glycol) and BHAPE. The bonding strength, thermal stability, flame retardant performance, mechanical properties and hydrolytic resistance of the HMPURs were studied. The results illustrate that the incorporation of BHAPE for HMPURs could cause a higher thermal stability and more char yield. The melt viscosity, Young's modulus, tensile strength and elongation at break of HMPURs increase with the increase of BHAPE content, and then decrease when the BHAPE content reaches 4 wt%.The optimal content of BHAPE is 4-6wt% and the obtained HMPURs have the limit oxygen index (LOI) of 27.1-31.7% and the higher green strength. Meanwhile, introducing polycarbonate diol to HMPUR can effectively improve its hydrolysis resistance.

Automated summary

The novel phosphorus-nitrogen-containing polyol BHAPE synthesized through Kabachnik-Fields reaction showed enhanced thermal stability and flame retardant properties in HMPURs. Increasing BHAPE content within a certain range can improve the mechanical properties of HMPURs, with an optimal content of 4-6wt%. Furthermore, introducing polycarbonate diol can effectively enhance the hydrolysis resistance of HMPURs.