Reactive hot melt polyurethane adhesives modified with pentaerythritol diacrylate: synthesis and properties

Pentaerythritol diacrylate (PEDA) was synthesized by direct esterification from acrylic acid and pentaerythritol, and the reactive hot melt polyurethane adhesives (PURs) with high green strength were prepared from Poly(1,6-hexamethyleneadipate), PHA-3000, two kinds of Poly(propylene glycol) (PPG-1000 and PPG-4000) and PEDA as well as terpene-phenolic resin. Five samples of PURs with different weight percent (α) of PEDA (α = 0, 3, 5, 7, and 10 wt%), were obtained. The rheological properties, thermal stability, and mechanical properties of the samples were investigated. The results showed that the melt viscosity (η) and the storage shear modulus of the samples increase with the increase in α, while the thermal stability changes little. The bonding strength of the samples after 10 min, 30 min, and 48 h was assessed by 180° peel tests of Fabric 6535/adhesives/Fabric 6535 stacks. The results showed that the green strength after 30 min increases with the increase in α when α is not higher than 7 wt%.