Study On Waste Recycling Of Polyester Fabric

China is the textile industry big country, is also a big consumer of textiles.So our annual textile waste generated up to thousands of tons of the giant. Today,the comprehensive utilization of recycling of waste textiles in China has juststarted. Therefore, the resource utilization of waste textiles actually get less thanone-tenth. Parts that fail to effectively reuse not only waste resources, and havebrought environmental problems.Polyester (polyester or PET) fabric occupy a large proportion in the wastetextiles, therefore, how to through the reasonable and effective way to makewaste polyester fabric can then reuse the problem before us urgent. In recentyears, our country have been presents the increasing trend of polyesterproduction polyester production of33.2761million tons, in2013in Chinaaccounted for more than seventy percent of the total world output, but used inthe production of polyester raw materials paraxylene (PX) is heavily dependenton imports. Our dependence on foreign paraxylene up to53%, and the gapcontinues to increase in2013. Unfortunately, the current consumed almost allpolyester fabric was used as landfill or incineration, the comprehensive utilization rate of less than1%. Therefore developing the dacron polyesterrecycling technology has become the key to the development of the dacronpolyester industry. Today, PET recycling use of the method mainly has the acidhydrolysis, alkaline hydrolysis method, neutral hydrolysis method, methanoldiol and ethylene glycol diol, neutral hydrolysis of waste PET is, however, mostto have the prospects for development. In this experiment, after the pretreatmentof waste polyester fabric as the raw material, the subcritical water as solution inautoclave to degradation of polyester fabric. Using nitrogenN-dimethylformamide (DMF) stripping system for waste polyester fabricpre-stripping process discussed feed ratio (mass ratio of deionized water andpolyester fabric), reaction temperature, holding time degradation of PET ratesand whiteness, purity, affecting product acidity, and PET hydrolysis mechanismunder subcritical water conditions, a preliminary exploration reveals poly(ethylene terephthalate) under hydrothermal conditions and hydrolysis processreaction mechanism, and finally the resulting white solid TPA degradation of thequality indicators were measured.(1) This article discusses the clear before stripping treatment of wastepolyester fabric is mainly divided into swelling agent to swell and disperse thereduction stripping stripping three processes. This selection of the swellingagent is dimethyl sulfoxide (DMSO), disperse dyes of the stripping agentpreferably DMF, the reducing agent is thiourea dioxide (TDO). determine theoptimum conditions for the stripping process: Stripping time is30min, stripping temperature controlled at140℃.(2) The neutral hydrolysis of recycling waste polyester fabric, resourceproducts are TPA and EG, the feed ratio (quality deionized water and polyesterfabric ratio), reaction temperature and holding time is the factor of hydrolysis ofpolyester fabric as the main influence, the optimal hydrolysis conditions: thefeed ratio.10:1, the temperature of250DEG C, the reaction time is7h. Underthe optimal conditions, PET degradation rate can reach to92.9%, the yield ofTPA was86.4%, the purity of TPA was98.251%, the acidity of TPA up to657.14mgKOH/g.(3) The hydrolysis mechanism of PET: in high temperature and highpressure water will be ionized into H+and OH-, H+and-COOR in group C+,while water H attack in-COOR C, the formation of the intermediate product oftetrahedron. Then, the water H away, O on electron transfer occurs, the acyloxygen bond cleavage, the degradation of TPA and EG.(4) Has been clear about the PET hydrolysis generated TPA qualityindicators meet the purified terephthalic acid (PTA)(PTA) standardexperimental conditions: reaction temperature250℃or higher,8h reactiontime, feeding ratio10:1, drying temperature100℃, the drying time8h.