Composite catalyst and polypropylene terephthalate preparation method

Composite catalyst and polypropylene terephthalate preparation method

  • CN 104,774,320 B
  • Filed: 03/27/2015
  • Issued: 12/14/2018
  • Est. Priority Date: 03/27/2015
  • Status: Active Grant
First Claim
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1. a kind of polypropylene terephthalate preparation method, using terephthalic acid (TPA) and 1,3-PD as raw material, through being esterifiedThe polypropylene terephthalate is prepared in reaction and polycondensation reaction, it is characterised in that with composite catalyst is catalysisAgent, the composite catalyst include positive four butyl ester of metatitanic acid and phosphite ester, the quality of metatitanic acid positive four butyl esters and phosphite esterThan being 0.6~1.15, judge whether esterification is completed according to esterification water, the esterification water condensation that will be steamed, in esterification waterAfter reaching theoretical amount or technology controlling and process amount, into the polycondensation reaction, the height that inherent viscosity is 0.85~1.07 dL/g is preparedViscosity products, and product color is white, not yellowing, main process flow includes:

  • Mashing;

    starting the stirrer-driven motor of reaction kettle, and the raw material measured is put into reaction kettle, stirs 10 minutes, adjustsIt is made into uniform sizing material;

    Esterification;

    after slurry preparation is good, starts to control certain temperature and pressure progress esterification, be esterified water and the evaporation of generationDihydric alcohol enter still and separated, by capital cooler control tower item temperature, separate esterification water, through being esterifiedAfter water condenser is cooling, it is directly entered esterification water receiving tank with a scale and is measured, esterification degree is judged, after condensationEsterification water reach theoretical value or the technological standards value of setting after, it is believed that esterification complete, into subsequent polycondensation reaction;

    Precondensation;

    after esterification, closing the pipeline valve of fractionation side, open the pipeline valve of polycondensation side, in heating shapeCarry out precondensation is vacuumized to reactor under state, in precondensation stage, vacuum is slowly established by the roughing pump of process control, byThe dihydric alcohol extracted out in reaction system, which mainly enters after polycondensation condenser is cooling, condenses thick ethylene glycol receiving tank, and reaction terminatesThe dihydric alcohol of discharge is measured, and absorbs low boiling component using cryotrap and investigates side reaction situation;

    Final minification is poly-;

    after prepolymerization reaction, further increasing reaction temperature and system vacuum, vacuum is by high-vacuum pump realityIt is existing, the small molecule in reaction system is discharged, the growth of strand is promoted, the dihydric alcohol being discharged from reactor passes through escape pipeInto polycondensation condenser, for cooling heel row into the thick ethylene glycol receiving tank of condensation, reaction terminates the dihydric alcohol of metering discharge, and utilizes lowWarm cold-trap absorbs low boiling component and investigates side reaction situation, finally judges reaction end with the stir current of reaction kettle;

    Pelletizing;

    the N of polymer melt 0.2-0.3MPa after the reaction was completed2It extrudes, it is cold by cooling trough by baiting valveBut, then through dry machine-cut of cutting at particle.

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