Study On The Preparation Of Polyvinyl Butyral With Solid Acid As Catalyst

Polyvinyl butyral（PVB）has good flexibility,ductility,heat resistance and transparency.It is an ideal laminated film material.In recent years,with the rapid development of automobile and construction industry,the demand for safety glass is also increasing rapidly,and the market demand for safety glass intermediate film PVB resin is also growing rapidly.At present,the domestic manufacturers use two-step precipitation method to synthesize PVB resin.The catalysts used are liquid acid catalysts,which are easy to cause equipment corrosion,difficult to separate catalysts,and a large number of waste water to be treated.In this paper,PVB resin with high acetal degree and good physical and chemical properties was obtained by preparing solid acid catalyst and using it to synthesize PVB.The main results are as follows:（1）The sulfonated acid ion exchange resin catalyst was prepared and the preparation conditions were optimized:the sulfonated acid ion exchange resin was immersed in concentrated sulfuric acid at 110℃,washed and dried after sulfonation for 12 hours,and the specific sulfonated acid ion exchange resin catalyst was about3.92 mmol/g.The synthesis conditions of PVB were optimized.When sulfonated acid ion exchange resin was used as catalyst,the preparation conditions of PVB were as follows:reaction at 95℃for 11 hours,adding 8%solvent（ethanol:water）ratio（volume ratio）1.1:1 of total solid amount,n-butanal amount:PVA amount 70:100（mass ratio）.（2）The recovery and regeneration of sulfonated acid ion exchange resin catalyst were investigated.It was found that the recovery efficiency was good,but the activity of catalytic acetalation decreased after recycling.In addition,the separation methods of catalyst,product,solvent and wastewater treatment after acetalization were studied.（3）The solid superacid catalysts ZrO₂/S₂O₈^2-,Fe₂O₃/S₂O₈^2-were prepared and the preparation conditions were optimized.ZrO₂/S₂O₈^2-and Fe₂O₃/S₂O₈^2-were used to catalyze the reaction of n-butyraldehyde with PVAto form PVB,and their catalytic activity was found to be low.（4）The PVB products were characterized by FT-IR and GPCwere used to analyze and characterize the PVB products.The results show that the PVB resin prepared in this experiment is comparable to that of commercial PVB resin prepared by liquid acid,and can meet the requirements of safety glass intermediate film production.