Study On Modification And Property Of Soy-based Protein Adhesives

In order to reduce the viscosity and increase the bonding strength of the soy-based protein adhesive, to meet the needs of industrial scale production of wood-based panel, dibutyl phthalate, modifier A, lauryl sodium sulfate, viscosity reducer A(purchase), sodium dodecyl benzene sulfonate(SDBS), and sodium dodecyl sulfate(SDS) were employed to modify the soy protein adhesives. The effects of the six modifiers on the viscosity and bonding strength of soy-based protein adhesive were investigated. By using soy-based protein adhesive to compound with the reinforced resin (PF), the influence of different modifiers and different technologies on the bonding strength and formaldehyde emission of plywood bonded by the modified soy-based protein adhesives were researched. The curing characteristic and thermal behavior of the modified soy-based protein adhesives were also studied by FTIR and thermal analysis. The results of this study were summarized as follows:1. Taking viscosity and bonding strength into consideration, the modifier A showed a positive effect on soy-based protein adhesive. Modifier A reduced the viscosity and promoted coatability of the adhesive, and showed no negative impact to the bonding strength of soy-based protein adhesive.2. At pH value 12, the plywood boned with the sodium hydroxide modified soy-based protein adhesive could reach a 0.7 MPa bonding strength, meeting the requirement of type II plywood of GB/T 17657-1999.3. Multivariate amine modifier could effectively reduce the formaldehyde emission of the plywood bonded with the reinforced resin, and showd little effect on the bonding strength. when the addition amount of the multivariate amine modifier was 9.2% or 13.8%, the plywood could reach 1.30 MPa bonding strength, meeting the requirement of type I plywood of GB/T 17657-1999, and the formaldehyde emissions was less than 0.1 mg/L, meeting the Japan F**** standards. The results of FTIR analysis confirmed that there was condensation reaction between multivariate amine modifier and the reinforced resin in the thermal curing process. By DSC analysis, it was proved that multivariate amine modifier could reduce the peak curing temperature of reinforced resin. 4. The bonding strength of the plywood bonded with a compound adhesive, mixed by modified Soy-based protein adhesive and reinforced resin at 7:3 mass ratio, was greater than 0.9 MPa, meeting the requirement of type I plywood of GB/T 17657-1999, and its formaldehyde emission was about 0.1 mg/L, meeting the Japan F**** standards. FTIR showed that the -NH-CH2- structures were generated by the reaction of soy protein and reinforced resin during the curing process of compound adhesive in this research.