Abstract
To improve the heat resistance of an aqueous vinyl polymer solution-isocyanate adhesive (API), we examined the film properties and the wood bonding performance of polyvinyl alcohol (PVA), which is generally used as a base polymer for API, with addition of montmorillonite, a form of clay. We measured the viscosity of the PVA solution with addition of montmorillonite in terms of the time required for mixing, the dynamic viscoelasticity, and the X-ray diffraction of a film made from the PVA solution with addition of montmorillonite. The viscosity of the PVA/montmorillonite solution increased with increasing mixing time. X-ray diffraction analysis showed that the layer of montmorillonite expanded after mixing with PVA. These properties demonstrated that the interaction between PVA and montmorillonite increased after mixing the two compounds. The storage modulus at high temperatures of the PVA/montmorillonite mixture was ten times that of PVA alone. In wood bonding, the bond strength of the PVA/montmorillonite mixture increased at high temperatures. These results show that adding montmorillonite to PVA increases the heat resistance of the adhesive.
