Process for the continuous preparation of high molecular weight polyesters and device for carrying out the method.

摘要

Process for the continuous preparation of polyesters of high molecular weight by esterification of dicarboxylic acids and / or transesterification of dicarboxylic acid esters with diols in the presence of catalysts with formation of a prepolymer and polycondensation to polyesters of high molecular weight, wherein a1) a paste and / or a suspension of the dicarboxylic acid and the diol is prepared, maintaining a mole ratio of diol to dicarboxylic acid of 0.8 to 1.8, a temperature between 20 and 90 ° C and a pressure between 10 and 100 kPA, or a2) the dicarboxylic acid ester is melted and mixed with the diol in a mole ratio of diol to dicarboxylic acid ester of 1.2 to 1.8 with a temperature of 145 to 165 ° C, b) products a1) and / or a2) are fed continuously to a tower reactor and the reactor tower is then performed continuously, simultaneously and without disruption esterification and / or transesterification until precondensation, the following provisos: b1) products of a1) and / or a2) are subjected to a treatment at a temperature of 170-270 ° C and a pressure of 30 to 300 kPa, being added in the first step reaction a partial amount of the catalyst and eliminating in situ reaction vapors of the reaction mixture by a hydrocyclone, b2) the product of reaction step b1) is carried continuously by a tubular section and is maintained at a pressure of 100 to 1000 kPa and a temperature of 200 to 280 ° C, being added in this reaction step 0.03 to 0.3 mol of diol, b3) the product of step b2 reaction) is carried continuously through a cascade of downstream with at least two plates, which are automatically reduced pressures in the range of 20 to 100 kPa and temperatures automatically increase of 230-280 ° C, being added in the third zone of 0.02 to remain 0.2 moles of diol and a partial amount of catalyst b4) the product from reaction step b3) is subjected to further reaction in a reaction zone falling film to 1 to 10 kPa and 240 to 280 ° C, and b5 ) the reaction product water or methanol, by-products and excess diol from reaction steps b1) and b3) to b4) are removed and after purification the diol is reintroduced in the different reaction steps c1) the prepolymer obtained from b4) is continuously polycondensed in the conventional polycondensation apparatus at temperatures of 240-290 ° C and pressures of 0.02 to 0.3 kPa or c2) the obtained prepolymer is frozen, it becomes pellets and subjected a postcondensation in solid phase at temperatures between 160 and 230 ° C under conditioned inert gas.