The Synthesis And Research Of Modified Soybean Protein Adhesive Based On Urea

With the rapid development of wood industry,production of wood adhesive has become the measurement of the development level for a country's wood industry.There are three main kinds of industrial wood adhesive in China,they are urea-formaldehyde resin,phenolic resin and melamine formaldehyde resin.These synthetic resin will release formaldehyde during use,which is harm to human body.To solve this problem,in this article,we exploring a kind of eco-friendly synthesis adhesive process,which is low cost and meet the national standard,as a substitute for existing industrial adhesives.According to the existing industrial production needs,this paper proposes three paths of synthesis adhesive based on the compound modification of urea.The adhesive of all three processes in certain range of viscosity number,solid content and bonding strength.Three kinds of compound modifications are urea-phosphorylation,urea-microcrystalline cellulose and urea-graft copolymerization compound modification.Among those three processes,graft copolymer compound modification can help us synthesis adhesive nearest to the requirements of producing adhesives.Otherwise,the addition of organic nano-montmorillonite materials is helpful to decrease the adhesive's viscosity,increase the solid content and improve the stability.The optimum synthesis process is as follow:SPI 10g,Urea solution(3 mol/L)100 mL,Sodium bisulfite 0.2 g,Ammonium persulfate 0.4 g,Glycidyl methacrylate 3.36 g,Organic nano-montmorillonite 0.5 g.The synthesis adhesive's viscosity is 1547 mpa·s and solid content is 26.02%.For two 50 mm×20 mm×3 mm,0.75 g/cm3 high-density fiberboard,under the condition of 100?hot-pressing temperature,1.0 MPa pressure,2 min hot-pressing time,approximately 280 g/m~2 glue spread,its shear strength can reach 1.34 MPa and the water resistance can reach 67.16%.Through the research above,the viscosity of eco-friendly soybean protein adhesives synthesized by using urea-graft copolymerization the preparation of compound modification can reach between 1000~3000 mpa·s.And the solid content is between 25%~30%.In consequence the agglutination intensity meet the requirement of national standard.It has a certain reference and guidance significance for the modification research and industrial production of soy protein adhesives in the future.