Preparation And Application Research Of Formaldehyde-Free Soybean-Protein-Based Fire-Retardant Adhesive

Fire-retardant and formaldehyde-free adhesive is a kind of environment protective and functional adhesive. Applying the adhesive to the production of particleboard can meet the healthy and eco-friendly requirements of people. In this paper, the inexpensive and renewable soy flour was used as raw materials. To prepare environmentally friendly and fame retardancy adhesive, the soybean flour was modified by alkali and appropriate flame retardants were added. Then the adhesive was used to prepare flame retardant particleboards. The main contents of this study were investigated as follows:Study on the modification of soy-bean flour:Soy-bean flour was modified by alkali, and the influences of additive amount of alkali, reaction temperature and time on the viscosity of the modified soy-bean adhesive were studied. The structure of the modified soy-bean protein was characterized by XRD and FT-IR, and the water resistance performance was characterized by water absorbtion rate and dissolve-loss ratio test. The experimental results showed that when the alkali dosage was 3.3% (based on the mass of soy flour), reaction temperature was 50℃ and reaction time was 30min, the modified soy-bean protein achieved the best modification effect. At this monment, the viscosity of the soy-bean protein adhesive was moderate, the crystallinity of the soy-bean protein could be destroyed and the water absorption rate and dissolve-loss ratio was the low.Preparation of flame retardants and flame retardant adhesives:The influences of reaction condition on the product compositon and partice size disteibution of zinc borate (ZB) were detailed investigated. The thermostability differences of the obtained zinc borates were also disscused. We distributed the zinc borate with best thermostability into modifided soy-bean adhesive. The influences of adding method on the compatibility between zinc borate and adhesive and the water absorption rate and dissolve-loss ratio were investigaeted. Best result was obtained by first disoersed zinc borate in water and then modified the soy-bean flour. When the additive amount of zinc borate was 0.8g, the comprehensive effect of flame retardant adhesive was best. Applied the results to the production of calsium borate (BA) and melamin phosphoate (MP) adhesive, and when the additive amount of BA and MP was 0.8g and 2.5g respectively, it could rechived the best flame retardancy.Based on the above, flame retardancy adhesive was applied to the preparation of flame retardancy particleboard. Influence of different single and composite kinds of flame retardants on the properties of particleboards were disscused. The particleboard with ZB only showed best and BA also showed well flame retardancy but has a negative influence on the physical and mechanical properties of the board. While the particleboards with MP-ZB and AMB showed the best flame retardancy. But the board with MP-ZB would release a lot of smoke in the process of heating and would play havoc with mechanical performance of the boards. On the contrace, AMB would raise the mechanical performance of the boards slightly. And the best results were obtained by the particelboards addived AMB.It was showed that the flame retardant protein adhesive, with the soy-bean protein flour as raw material, possessed excellent flame retardancy and application performance. Application the flame retardant adhesive to the production of particleboard can meet the requirements of environmental and flame retardancy, according to the way of the development of adhesive and artificial board industry, and possess the good foreground of development and application.