Abstract
The following experiments were carried out in order to clarify the reason of the excellent wood bonding performance of AA PVA when used as an adhesive. The surface activity performance of AA PVA was evaluated, and the relationship between the pMDI dispersion property in the PVA aqueous solution and the ability to consume isocyanate (NCO) groups was examined in comparison with ordinary PVA, which was used with varying degrees of polymerization and varying quantities and distribution of hydrophobic groups introduced into the side chain. By the measurement of the surface tension of various PVA aqueous solutions and the interfacial tension between the various PVA aqueous solutions and n-hexane, it was found that the AA PVA aqueous solution has low surface tension and low interfacial tension with n-hexane. By testing pMDI dispersion in the various PVA aqueous solutions, the AA PVA aqueous solution was found to have high oil component dispersion performance and to have the ability to disperse the oil component in aqueous solution into smaller particles than ordinary PVA does. AA PVA also demonstrated rapid consumption of NCO groups in the PVA aqueous solution. From the above mentioned, the AA group was found to have excellent interface activity, not only as a hydrophobic group, but also as a functional group, with reactivity that disperses the oil component into aqueous solution.
