Waste Polyvinyl Butyral Plastic Bleaching Technology

Polyvinylbutyral(PVB)is a kind of synthetic resin,which is synthesized by polyvinyl alcohol and butyraldehyde with acid catalysis, and it's the optimal material to make the interlayer of safe glass.The important problem is the separation of PVB resin and pigment in the study PVB plastic recycling,because most of PVB films are coloration. The study was began from the deliquescent capability,the separation and recycling of PVB resin and pigment was triumphantly achieved by the operation of"solvent dissolving,pigment extracted and PVB separated by water" and "dissolving pigment selectively and evaporation recovery of solvent".Different dissolving character between PVB resin and pignmnt in solvent was studyed in beginning.The technologic flows of the methods of "solvent dissolving,pigment extracted and PVB separated by water" and "dissolving pigment selectively and evaporation recovery of solvent" were researched.The methods of "solvent dissolving,pigment extracted and PVB separated by water" adopted the technique of extracting pigment time after time.This flow of technics was lang,wasting time and energy,being unfit for industrialisation.Systematically researching of decoloration condition,recycling of solvent and plasticizer,industrialisation design of the methods of"dissolving pigment selectively and evaporation recovery of solvent".Calculating according to the configuration of PVB,then mensurating by turbidity titrimetry,the solubility parameter of PVB resin was 21.79～24.38(J/cm³)^1/2.In the article twenty different kinds of solvents were systems analysis by the theory of solubility parameter and dissolving degree,the TSJ-1311 which could be used in the decoloration of PVB plastic and was innocuity was empoldered.According to the method of dissolving pigment selectively -evaporation recovery of solvent,the navy blue waste PVB plastic was the object of decoloration,the factors which were affected the decoloration were examined.The optimized decoloration time and ratio of liquor to material in single grade are 40min and 30:1 respectively,and the optimized decoloration times was 3,and in this condition achromatous PVB was achieved.The optimal technological conditions of recycling solvent were also studied:solvent recycling temperature was 55℃in water-bath and the pressure was 0.07MPa(vacuum degree).The constitution and configuration of TSJ-1311 were almost the same before and after recycling by IR spectra determination,so it could be used in the process of decoloration again.In the optimal technological conditions,the recovery of TSJ-1311 were over 96%.Plasticizer was recycled in the condition of 230℃in oil-bath and the pressure was 0.08MPa(vacuum degree)Stroe trough,decoloration reactor,still,heat exchange equipment which in the factory that disposed 2t waste PVB every day were designed.The results were:TSJ-1311 was 1.20×10³L/d;the height and breadth of still were 23m and 13m;steam need was 1099.7kg/h. This method has simple technology,convenient operation and lower energy waste,the recycled achromatous PVB was pure and more valuable.Therefore the method of dissolving pigment selectively -evaporation recovery of solvent had an actively instructional effect on field of waste plastic recycling.