阅读说明：本技术 一种1,4;3,6-二缩水己六醇改性pet聚酯及其半连续制备方法 (1,4, 3, 6-diglycidyl hexaol modified PET polyester and semi-continuous preparation method thereof ) 是由 刘佳健 李春成 孟现明 张栋 于 2019-11-12 设计创作，主要内容包括：本发明公开了一种1,4；3,6-二缩水己六醇改性PET聚酯及其半连续制备方法,改性PET聚酯的单体包括：(a)对苯二甲酸(b)乙二醇(c)1,4；3,6-二缩水己六醇或其混合物(d)脂肪族和/或脂环族二元醇。该方法是在第一酯化釜内制备一定量的对苯二甲酸乙二醇酯化物,然后将混合好的对苯二甲酸和乙二醇浆料以一定的流量连续加入第一酯化釜内使之反应,而反应产物间歇部分排入第二酯化釜,第二酯化釜中加入改性单体/酯交换催化剂进行酯化/酯交换反应得到预聚物,再全部排入缩聚釜并加入缩聚催化剂进行熔融缩聚得到最终聚合物。本发明的方法克服了生物基单体反应活性低、转化率低和生产成本高的难题,避免了金属残留问题,有利于实现工业化生产。(The invention discloses a 1,4;3, 6-diglycidyl hexaol modified PET polyester and its semi-continuous preparation method, the monomer of the modified PET polyester includes: (a) terephthalic acid (b) ethylene glycol (c)1, 4;3, 6-dianhydrohexitol or a mixture thereof (d) aliphatic and/or cycloaliphatic diols. Preparing a certain amount of ethylene glycol terephthalate in a first esterification kettle, continuously adding mixed terephthalic acid and ethylene glycol slurry into the first esterification kettle at a certain flow rate to react, discharging intermittent parts of reaction products into a second esterification kettle, adding a modified monomer/ester exchange catalyst into the second esterification kettle to perform esterification/ester exchange reaction to obtain a prepolymer, completely discharging the prepolymer into a polycondensation kettle, and adding a polycondensation catalyst to perform melt polycondensation to obtain a final polymer. The method of the invention overcomes the problems of low reaction activity, low conversion rate and high production cost of the bio-based monomer, avoids the problem of metal residue and is beneficial to realizing industrial production.)

1.1, 4;3, 6-diglycidyl hexaol modified PET polyester, characterized by, 1,4; the structural general formula of the 3, 6-diglycidyl-hexitol modified PET polyester is shown as formula I:

in the formula I, R is aliphatic and/or alicyclic alkyl dihydric alcohol with the main chain carbon atom number of 2-20;

in the formula I, the 1,4:3, 6-diglycidyl hexaol structural unit is selected from at least one of isosorbide shown in a formula II, isomannide shown in a formula III and isoidide shown in a formula IV,

2. 1,4; the 3, 6-diglycidyl-hexitol modified PET polyester is characterized in that the molar content of a 1,4:3, 6-diglycidyl-hexitol structural unit in the formula I is 8-90 percent calculated by the total molar weight of copolyester diols; the molar content of the ethylene glycol structural unit is 1-90%, and the molar content of other diol structural units is 1-90%.

3. 1,4 according to claim 1 or 2; the 3, 6-diglycidyl-hexitol-modified PET polyester is characterized in that in the formula I, R is aliphatic or alicyclic hydrocarbon dihydric alcohol with the main chain carbon atom number of 2-8.

4. 1,4 according to any one of claims 1 to 3; 3, 6-diglycidyl hexaol modified PET polyester, characterized by, 1,4; the intrinsic viscosity of the 3, 6-diglycidyl-hexitol modified PET polyester is 0.5-1.2 dL/g, and the glass transition temperature is 40-130 ℃;

preferably, the intrinsic viscosity is 0.5-0.9 dL/g, and the glass transition temperature is 65-110 ℃.

5. A method of producing a polypeptide of 1,4; the preparation method of the 3, 6-diglycidyl hexaol modified PET polyester is characterized by comprising three steps of esterification reaction, diester reaction and melt polycondensation reaction, and comprises the following specific steps:

(1) an esterification reaction: preparing esterification products from terephthalic acid and ethylene glycol under the conditions of high temperature and high pressure in a first esterification kettle in the atmosphere of inert gas, and discharging most of the esterification products into a second esterification kettle; continuously adding terephthalic acid and ethylene glycol slurry into a first esterification kettle, and continuously carrying out esterification reaction with the residual esterified substance in the first esterification kettle;

(2) and (3) carrying out diester reaction: adding terephthalic acid and 1,4 into the esterification product in the second esterification kettle; 3, 6-diglycidyl hexanol or mixture thereof, dihydric alcohol and ester exchange catalyst, carry on the second step esterification reaction under the normal pressure condition, and remove the by-product produced in the esterification reaction, get the prepolymer of copolyester;

(3) melt polycondensation reaction: discharging the prepolymer into a polycondensation kettle, adding a polycondensation catalyst, gradually establishing vacuum conditions, and carrying out polycondensation reaction to prepare random copolyester;

preferably, in the step (2), terephthalic acid, ethylene glycol and 1,4;3, 6-diglycidyl hexanol or the mixture thereof, dihydric alcohol and ester exchange catalyst to carry out the second esterification reaction.

6. The production method according to claim 5, wherein in the step (2), the diol is an aliphatic and/or alicyclic diol having 2 to 20 carbon atoms;

preferably, the diol is at least one of 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 2, 2-dimethyl-1, 3-propanediol, 1, 6-hexanediol, 1, 2-cyclohexanediol, 1, 4-cyclohexanediol, 1, 2-cyclohexanedimethanol, 1, 3-cyclohexanedimethanol, and 1, 4-cyclohexanedimethanol.

7. The production method according to claim 5 or 6, wherein in the step (2), the transesterification catalyst is at least one of metal oxides, metal hydroxides, metal alkoxide compounds, metal phosphates, metal sulfates, metal acetylacetone complexes, metal acetates, and metal halides of magnesium, zinc, manganese, aluminum, cobalt, and tin;

preferably, the transesterification catalyst is at least one of magnesium oxide, magnesium hydroxide, magnesium stearate, magnesium sulfate, magnesium acetate, magnesium chloride hexahydrate, zinc oxide, zinc hydroxide, zinc stearate, zinc phosphate, zinc sulfate, zinc acetylacetonate, zinc acetate, zinc chloride, manganese oxide, manganese acetylacetonate, manganese sulfate, manganese acetate, manganese chloride, aluminum oxide, aluminum hydroxide, aluminum phosphate, aluminum sulfate, aluminum acetylacetonate, aluminum acetate, cobalt oxide, cobalt acetylacetonate, cobalt acetate tetrahydrate, cobalt chloride, cobalt salicylate, dibutyltin oxide, dibutyltin dilaurate, dibutyltin dichloride, tin tributylacetate, tributyltin chloride, and trimethyltin chloride.

8. The production method according to any one of claims 5 to 7, wherein in the step (3), the polycondensation catalyst is at least one of an organic metal compound or oxide or complex of titanium, antimony, silicon, germanium or zirconium;

preferably, the polycondensation catalyst is at least one of titanium dioxide, silicon dioxide/titanium dioxide composite, zirconium dioxide/titanium dioxide composite, ethylene glycol titanium, tetraisopropyl titanate, tetrabutyl titanate, tetraethyl titanate, lithium titanyl oxalate, antimony trioxide, ethylene glycol antimony, antimony acetate, germanium oxide and germanium acetate.

9. The production method according to any one of claims 5 to 8, wherein in the step (1), the molar ratio of terephthalic acid to ethylene glycol is: 1: 1-3;

preferably, in the step (2), the molar ratio of carboxyl groups to hydroxyl groups is: 1: 1-3, wherein the mass of the ester exchange catalyst is 2-800 ppm of the theoretical yield of the random copolyester;

preferably, the mass of the polycondensation catalyst is 3-500 ppm of the theoretical yield of the random copolyester.

10. The method according to any one of claims 5 to 9, wherein in the step (1), the esterification reaction temperature is 200 to 260 ℃; the total time of the esterification reaction is 2-20 hours;

preferably, in the step (2), the esterification reaction temperature is 180-240 ℃; the total time of the esterification reaction is 2-20 hours;

preferably, in the step (3), the temperature of the polycondensation reaction is 200-300 ℃, the time of the polycondensation reaction is 1-48 hours, and the pressure of the reaction system during the polycondensation reaction is less than 200 Pa.

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to a 1,4;3, 6-diglycidyl hexaol modified PET polyester and a semi-continuous preparation method thereof, in particular to a method for preparing high-performance 1,4 by a semi-continuous mode with high efficiency and high conversion rate; 3, 6-diglycidyl hexachloro-ethane is used for modifying PET copolyester.

Background

Polyethylene terephthalate (PET) has the advantages of good strength and toughness, no toxicity, weak acid resistance, organic solvent resistance and the like, so that the PET is widely applied to the fields of packaging materials, beverage bottles, textile and clothing products and the like. However, the development of PET is limited by the problems of excess capacity and low additional value, and differentiation and functional modification become a new direction for the development of PET. The PET has poor heat resistance, and can generate serious deformation and greatly reduce the performance when being used at a higher temperature, so the development of the novel high-modulus high-heat-resistance modified PET polyester becomes a problem which is concerned about and needs to be solved urgently.

1,4;3, 6-Diglycidohexanol is a rigid bio-based diol monomer obtained from starch in cereals by catalytic decomposition, hydrogenation and further dehydration. It exists in three isomers, namely isosorbide, isomannide and isoidide. Among them, isosorbide is currently the only sugar diol that realizes mass industrial production. Isosorbide has a rigid structure and is a chiral molecule, so that isosorbide becomes an ideal raw material for synthesizing a polymer with high glass transition temperature (high heat resistance) or excellent mechanical properties, and meanwhile, isosorbide has the advantages of no toxicity, greenness and environmental protection. Isosorbide has been widely used in recent years for the synthesis of polycondensation polymers such as polyesters, polyurethanes, polyamides, polyestercarbonates, polycarbonates, and the like. The preparation of heat-resistant isosorbide copolyesters by reacting isosorbide, ethylene glycol and terephthaloyl chloride is described in the Journal of Applied Polymer Science,1996, 7, 1199-. The literature [ Journal of Polymer Science Part A Polymer Chemistry,2011,10, 2252-. The polymer has the characteristics of large rigidity of molecular structure, high Tg, high thermal stability and the like. However, the isosorbide has low reactivity, so that the prepared isosorbide-type polymer has the problems of insufficient molecular weight and high toxicity of using acyl chloride as a raw material, and the isosorbide conversion rate is low, so that the raw material waste and the production cost such as post-treatment are increased, which is a problem to be addressed with high attention.

In conclusion, aiming at the problems of low glass transition temperature of PET, poor heat resistance and poor reaction activity and low conversion rate of isosorbide, how to efficiently prepare high-strength high-heat-resistance modified PET polyester with high conversion rate, improve the additional value and expand the application range is a problem to be solved urgently.

The present invention has been made in view of this situation.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art and provide a 1,4;3, 6-diglycidyl hexaol modified PET polyester and a semi-continuous preparation method thereof. The method utilizes good solubility of the esterified substance to the monomer and the synergistic effect between the ester exchange catalyst and the polycondensation catalyst, overcomes the problems of low reaction activity, low conversion rate and high production cost of the bio-based monomer, has extremely low catalyst consumption in the reaction process, avoids the problems of complex catalyst separation process and metal residue in the polymer, and is more favorable for realizing industrial production in a semi-continuous mode.

In order to solve the technical problems, the invention adopts the technical scheme that:

a first object of the present invention is to provide a 1,4; the 3, 6-diglycidyl-hexitol modified PET polyester has a repeating unit structure shown in a formula I:

in the general structural formula of the formula I, R is aliphatic or alicyclic hydrocarbon dihydric alcohol with the main chain carbon atom number of 2-20;

in the formula I, the 1,4:3, 6-diglycidyl hexaol structural unit is selected from at least one of isosorbide shown in a formula II, isomannide shown in a formula III and isoidide shown in a formula IV,

in a further scheme, in the formula I, R is aliphatic or alicyclic hydrocarbon dihydric alcohol with the main chain carbon atom number of 2-8.

In a further scheme, calculated by the total molar weight of the copolyester dihydric alcohol, the molar content of the 1,4:3, 6-diglycidyl hexanehexaol structural unit in the formula I is 8-90%, the molar content of ethylene glycol unit is 1-90%, and the molar content of other dihydric alcohol units is 1-90%.

Further scheme, 1,4; the intrinsic viscosity of the 3, 6-diglycidyl-hexitol modified PET polyester is 0.5-1.2 dL/g, and the glass transition temperature is 40-130 ℃;

preferably, the intrinsic viscosity is 0.5-0.9 dL/g, and the glass transition temperature is 65-110 ℃.

A second object of the present invention is directed to 1,4;3, 6-diglycidyl hexanehexanol has low reaction activity and poor conversion rate, and provides a method for preparing high-performance 1,4 by adopting a semi-continuous mode with high efficiency and high conversion rate; the method for modifying PET by 3, 6-diglycidyl hexanol is green and environment-friendly and is beneficial to realizing industrial application.

The invention 1,4; the preparation method of the 3, 6-diglycidyl hexaol modified PET polyester comprises three steps of esterification reaction, diester reaction and melt polycondensation reaction, and comprises the following specific steps:

(1) an esterification reaction: preparing esterification products from terephthalic acid and ethylene glycol under the conditions of high temperature and high pressure in a first esterification kettle in the atmosphere of inert gas, and discharging most of the esterification products into a second esterification kettle; continuously adding terephthalic acid and ethylene glycol slurry into a first esterification kettle, and continuously carrying out esterification reaction with the residual esterified substance in the first esterification kettle;

(2) and (3) carrying out diester reaction: adding terephthalic acid and 1,4 into the esterification product in the second esterification kettle; 3, 6-diglycidyl hexanol or mixture thereof, dihydric alcohol and ester exchange catalyst, carry on the second step esterification reaction under the normal pressure condition, and remove the by-product produced in the esterification reaction, get the prepolymer of copolyester;

(3) melt polycondensation reaction: discharging the prepolymer into a polycondensation kettle, adding a polycondensation catalyst, gradually establishing vacuum conditions, and carrying out polycondensation reaction to prepare random copolyester;

preferably, in the step (2), terephthalic acid, ethylene glycol and 1,4;3, 6-diglycidyl hexanol or the mixture thereof, dihydric alcohol and ester exchange catalyst to carry out the second esterification reaction.

1,4 in the preparation method; 3, 6-dianhydrohexitol or a mixture thereof means added 1,4; the 3, 6-diglycidyl hexanol can be a single species or a mixture of two or three isomers.

In the step (2) of the above production method, the diol is an aliphatic and/or alicyclic diol having 2 to 20 carbon atoms;

preferably, the diol is at least one of 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 2, 2-dimethyl-1, 3-propanediol, 1, 6-hexanediol, 1, 2-cyclohexanediol, 1, 4-cyclohexanediol, 1, 2-cyclohexanedimethanol, 1, 3-cyclohexanedimethanol, 1, 4-cyclohexanedimethanol, and preferably is 1, 3-cyclohexanedimethanol and 1, 4-cyclohexanedimethanol.

In the step (1) for preparing the ester, the feeding molar ratio of the terephthalic acid to the ethylene glycol is 1: 1-3, more preferably 1: 1.1 to 2.

The primary esterification reaction in the step (1) adopts high-temperature high-pressure esterification reaction, the reaction temperature is 200-260 ℃, and preferably 220-260 ℃; the reaction pressure is 200-400KPa, preferably 200-300 KPa; the total time of the first esterification reaction is 2 to 20 hours, preferably 3 to 10 hours.

In the step (2) of preparing the prepolymer, the molar ratio of carboxyl to hydroxyl of the system is 1: 1-3, more preferably 1: 1.1-2; the purity of the 1,4:3, 6-diglycidyl hexanol is 99.0% or more, preferably 99.5% or more.

The diester reaction in the step (2) adopts high-temperature high-pressure esterification reaction, the reaction temperature is 180-240 ℃, and preferably 180-220 ℃; the total time of the diester reaction is 2 to 20 hours, preferably 3 to 10 hours.

In the step (2) of the above method, the added transesterification catalyst is at least one of metal oxides, metal hydroxides, alkoxy metal compounds, metal phosphates, metal sulfates, metal acetylacetone complexes, metal acetates and metal halides of magnesium, zinc, manganese, aluminum, cobalt and tin;

preferably, the transesterification catalyst is at least one of magnesium oxide, magnesium hydroxide, magnesium stearate, magnesium sulfate, magnesium acetate, magnesium chloride hexahydrate, zinc oxide, zinc hydroxide, zinc stearate, zinc phosphate, zinc sulfate, zinc acetate, manganese oxide, manganese acetylacetonate, manganese sulfate, manganese acetate, manganese chloride, aluminum oxide, aluminum hydroxide, aluminum phosphate, aluminum sulfate, aluminum acetate, cobalt oxide, cobalt acetylacetonate, cobalt acetate tetrahydrate, dibutyltin oxide, dibutyltin dichloride, tributyltin acetate, tributyltin chloride, and trimethyltin chloride.

In the step (3) of the above method, the polycondensation catalyst added before the polycondensation reaction is at least one of an organometallic compound, an oxide or a complex of titanium, antimony, silicon, germanium or zirconium; preferably at least one of titanium dioxide, silicon dioxide/titanium dioxide composite, zirconium dioxide/titanium dioxide composite, tetrabutyl titanate, tetraethyl titanate, antimony trioxide, ethylene glycol antimony, antimony acetate, germanium dioxide and germanium acetate.

In the step (3), the temperature of the polycondensation reaction is 200-300 ℃, preferably 240-280 ℃; the time of the polycondensation reaction is 1 to 48 hours, preferably 3 to 12 hours. The pressure of the reaction system during the polycondensation reaction is less than 200Pa, preferably less than 80 Pa.

After adopting the technical scheme, compared with the prior art, the invention has the following beneficial effects:

the invention provides a method for preparing high-performance bio-based modified PET (polyethylene terephthalate) in a semi-continuous mode with high efficiency and high conversion rate and 1,4 prepared based on the semi-continuous method; 3, 6-Diglycidohexanol modified PET polyester. The prepolymer has good solubility to reaction monomers, and the catalyst has obvious synergistic effect, thereby overcoming the problems of low reaction activity, low conversion rate and high production cost of bio-based monomers. 1,4; the conversion rate of the 3, 6-diglycidyl hexanol or the mixture thereof can reach more than 90 percent, the catalyst amount in the reaction process is extremely low, and the complex catalyst separation process and the metal residue in the polymer are avoided.

The copolyester obtained by the method is transparent colorless solid, has the intrinsic viscosity of 0.6-1.0, can be directly used as plastic, and has 1,4 in the main chain of the copolyester; the 3, 6-diglycidyl hexachloro-hexane or the mixture thereof has high content, accuracy and controllability, which greatly improves the heat resistance and mechanical property of PET.

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention to the right. It is obvious that the drawings in the following description are only some embodiments, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

FIG. 1 shows the 1H-NMR spectrum of the high heat-resistant high-performance isosorbide-modified PET prepared in example 1 of the present invention.

It should be noted that the drawings and the description are not intended to limit the scope of the inventive concept in any way, but to illustrate it by a person skilled in the art with reference to specific embodiments.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and the following embodiments are used for illustrating the present invention and are not intended to limit the scope of the present invention.

Intrinsic viscosity and thermal properties in the following examples were measured as follows;

intrinsic viscosity number: mixing 0.125g of 1,4; the 3, 6-diglycidyl hexanehexol modified furan diformyl random copolymer is dissolved in 25ml, and the mass ratio is 1: 1,1,2, 2-tetrachloroethane and phenol at 25 ℃.

Thermal properties: the polymer samples were analyzed using a TA Instruments Q2000 DSC. Weighing about 5mg of sample, placing the sample in an aluminum crucible, heating the sample to 240 ℃ from room temperature at a heating rate of 10 ℃/min in a high-purity helium atmosphere, keeping the temperature for 5min, cooling the sample to the room temperature at 20 ℃/min, and finally heating the sample to 220 ℃ at 10 ℃/min.

EXAMPLE 1 efficient preparation of high Heat resistant high Performance copolyester of terephthalic acid-isosorbide-ethylene glycol-1, 4-cyclohexanedimethanol by semi-continuous Process

(1) Under the protection of nitrogen atmosphere, 24.9kg (150mol) of terephthalic acid and 18.6kg (300mol) of ethylene glycol (the molar ratio of the terephthalic acid to the ethylene glycol is 1: 2) are added into a first esterification kettle, the pressure is increased to 300kPa, the reaction is stirred for 3 hours at the temperature of 240 ℃, and the byproduct water generated by the reaction is distilled out. When the byproduct water is completely evaporated, the reaction is complete, and terephthalic acid and glycol ester compounds are obtained; 2/3 esterified substance was discharged into the second esterification vessel, and 16.6kg (100mol) of a mixture of terephthalic acid and 12.4k g (200mol) of ethylene glycol was added to the first esterification vessel at a rate of 10kg/min to continue the esterification reaction with the remaining esterified substance.

(2) Adding 8.3kg (50mol) of terephthalic acid, 10.22g (70mol) of isosorbide, 4.32kg (30mol) of 1, 4-cyclohexanedimethanol and 8.5g of zinc acetate into the esterification product in the second esterification kettle in the step (1), carrying out the second esterification reaction/ester exchange reaction for 3.5 hours under the condition of normal pressure and 200 ℃, and distilling out the byproduct water and the ethylene glycol generated by the reaction. When the byproduct water and the ethylene glycol are completely distilled out, the reaction is complete, and the prepolymer of the copolyester is obtained.

(3) And (3) discharging the prepolymer obtained in the step (2) into a polycondensation kettle, adding 62.6g of antimony trioxide, gradually reducing the pressure and raising the temperature, enabling the pressure in a reaction system to be 80Pa, enabling the reaction end point temperature to be 270 ℃, and reacting for 5 hours to obtain the high-molecular-weight (terephthalic acid-isosorbide-ethylene glycol-1, 4-cyclohexanedimethanol) copolyester.

The copolyester was characterized to have an intrinsic viscosity of 0.85 dL/g.

The 1H-NMR spectrum of the (terephthalic acid-isosorbide-ethylene glycol-1, 4-cyclohexanedimethanol) copolyester is shown in FIG. 1, which indicates that the random copolyester has a correct structure; the Tg of the random copolyester was 107 ℃ as determined by DSC, demonstrating that the random copolyester has very good heat resistance.

EXAMPLE 2 efficient preparation of high Heat resistant high Performance copolyester of terephthalic acid-isosorbide-ethylene glycol-1, 3-cyclohexanedimethanol by semi-continuous Process

(1) Under the protection of nitrogen atmosphere, 24.9kg (150mol) of terephthalic acid and 23.25 g 23.25k g g (375mol) of ethylene glycol (the molar ratio of the terephthalic acid to the ethylene glycol is 1: 2.5) are added into a first esterification kettle, the pressure is increased to 300kPa, the reaction is stirred for 4 hours at 245 ℃, and the water generated as a byproduct in the reaction is distilled out. When the byproduct water is completely evaporated, the reaction is complete, and terephthalic acid and glycol ester compounds are obtained; 2/3 esterified substance was discharged into the second esterification vessel, and a mixture of 16.6kg (100mol) of terephthalic acid and 15.5kg (250mol) of ethylene glycol was fed into the first esterification vessel at a rate of 10kg/min to continue the esterification reaction with the remaining esterified substance.

(2) 8.3k g (50mol) of terephthalic acid, 3.41kg (55mol) of ethylene glycol, 6.48kg (45mol) of isosorbide, 14.6kg (100mol) of 1, 3-cyclohexanedimethanol and 10g of magnesium hydroxide are added into the esterification product in the second esterification kettle in the step (1), the second esterification reaction/ester exchange reaction is carried out for 3 hours under the condition of normal pressure and 190 ℃, and the by-product water and the ethylene glycol generated by the reaction are distilled out. When the byproduct water and the ethylene glycol are completely distilled out, the reaction is complete, and the prepolymer of the copolyester is obtained.

(3) And (3) discharging the prepolymer obtained in the step (2) into a polycondensation kettle, adding 55.3g of ethylene glycol antimony, gradually reducing the pressure and raising the temperature, enabling the pressure in a reaction system to be 70Pa, enabling the reaction end point temperature to be 285 ℃, and reacting for 4.5 hours to obtain the (terephthalic acid-isosorbide-ethylene glycol-1, 3-cyclohexanedimethanol) copolyester with high molecular weight.

The copolyester was characterized to have an intrinsic viscosity of 0.78 dL/g. The Tg of the random copolyester was 100 ℃ as determined by DSC.

EXAMPLE 3 efficient preparation of high Heat resistant high Performance copolyester of terephthalic acid-isosorbide-ethylene glycol-1, 4-cyclohexanediol by semi-continuous Process

(1) Under the protection of nitrogen atmosphere, 24.9kg (150mol) of terephthalic acid and 13.95kg (225mol) of ethylene glycol (the molar ratio of the terephthalic acid to the ethylene glycol is 1: 1.5) are added into a first esterification kettle, the pressure is increased to 280kPa, the reaction is stirred at the temperature of 250 ℃ for 3.5 hours, and the water generated as a byproduct in the reaction is distilled out. When the byproduct water is completely evaporated, the reaction is complete, and terephthalic acid and glycol ester compounds are obtained; 2/3 esterified substance was discharged into the second esterification vessel, and a mixture of 16.6kg (100mol) of terephthalic acid and 9.3kg (150mol) of ethylene glycol was fed into the first esterification vessel at a rate of 10kg/min to continue the esterification reaction with the remaining esterified substance.

(2) Adding 16.6kg (100mol) of terephthalic acid, 14.4kg (100mol) of isosorbide, 6.96kg (60mol) of 1, 4-cyclohexanediol and 15g of aluminum phosphate into the esterification product in the second esterification kettle in the step (1), carrying out the second esterification reaction/ester exchange reaction for 3.5 hours under the condition of normal pressure and 220 ℃, and distilling out the byproduct water and ethylene glycol generated by the reaction. When the byproduct water and the ethylene glycol are completely distilled out, the reaction is complete, and the prepolymer of the copolyester is obtained.

(3) And (3) discharging the prepolymer obtained in the step (2) into a polycondensation kettle, adding 1.6g of tetrabutyl titanate, gradually reducing the pressure and raising the temperature, enabling the pressure in a reaction system to be 60Pa, enabling the reaction end point temperature to be 273 ℃, and reacting for 3 hours to obtain the (terephthalic acid-isosorbide-ethylene glycol-1, 4-cyclohexanediol) copolyester with high molecular weight.

The copolyester was characterized to have an intrinsic viscosity of 0.67 dL/g. The random copolyester had a Tg of 115 ℃ as determined by DSC.

EXAMPLE 4 efficient preparation of high Heat resistant high Performance copolyester of terephthalic acid-isosorbide-ethylene glycol-1, 2-propanediol by semi-continuous Process

(1) Under the protection of nitrogen atmosphere, 49.8kg (300mol) of terephthalic acid and 19.53kg (315mol) of ethylene glycol (the molar ratio of the terephthalic acid to the ethylene glycol is 1: 1.05) are added into a first esterification kettle, the pressure is increased to 280kPa, the reaction is stirred at 255 ℃ for 4.5 hours, and the water generated as a byproduct of the reaction is distilled out. When the byproduct water is completely evaporated, the reaction is complete, and terephthalic acid and glycol ester compounds are obtained; 2/3 esterified substance was discharged into the second esterification vessel, and a mixture of 33.2kg (200mol) of terephthalic acid and 13.02kg (210mol) of ethylene glycol was fed into the first esterification vessel at a rate of 10kg/min to continue the esterification reaction with the remaining esterified substance.

(2) 16.6kg (100mol) of terephthalic acid, 2.4kg (40mol) of ethylene glycol, 17.28kg (120mol) of isosorbide, 0.76kg (10mol) of 1, 2-propanediol and 12g of cobalt acetylacetonate are added to the esterification product in the second esterification kettle in the step (1), the second esterification reaction/transesterification reaction is carried out for 5 hours under the condition of normal pressure and 240 ℃, and the by-products of the reaction, namely water and ethylene glycol are distilled out. When the byproduct water and the ethylene glycol are completely distilled out, the reaction is complete, and the prepolymer of the copolyester is obtained.

(3) And (3) discharging the prepolymer obtained in the step (2) into a polycondensation kettle, adding 8.6g of silicon dioxide/titanium dioxide compound, gradually reducing the pressure and raising the temperature, enabling the pressure in a reaction system to be 80Pa, enabling the reaction end point temperature to be 275 ℃, and reacting for 6 hours to obtain the (terephthalic acid-isosorbide-ethylene glycol-1, 2-propylene glycol) copolyester with high molecular weight.

The copolyester was characterized to have an intrinsic viscosity of 0.57 dL/g. The Tg of the random copolyester was 120 ℃ as determined by DSC.

EXAMPLE 5 efficient preparation of high Heat resistant high Performance copolyester of terephthalic acid-isosorbide-ethylene glycol-1, 4-cyclohexanedimethanol by semi-continuous Process

(1) Under the protection of nitrogen atmosphere, 2490kg (15000mol) of terephthalic acid and 2790kg (45000mol) of ethylene glycol (the molar ratio of the terephthalic acid to the ethylene glycol is 1: 3) are added into a first esterification kettle, the pressure is increased to 260kPa, the reaction is stirred at 250 ℃ for 3.8 hours, and the byproduct water generated by the reaction is distilled out. When the byproduct water is completely evaporated, the reaction is complete, and terephthalic acid and glycol ester compounds are obtained; 2/3 esterified substance was discharged into the second esterification vessel, and 1660kg (10000mol) of terephthalic acid and 1860kg (30000mol) of ethylene glycol mixture were added at a rate of 1000kg/min to the first esterification vessel to continue the esterification reaction with the remaining esterified substance.

(2) 830k g (5000mol) of terephthalic acid, 1296g (9000mol) of isosorbide, 876kg (6000mol) of 1, 4-cyclohexanedimethanol and 920g of tributyltin acetate are added into the esterification product in the second esterification kettle in the step (1), the second esterification reaction/ester exchange reaction is carried out for 4 hours under the condition of normal pressure and 205 ℃, and the by-product water and ethylene glycol generated in the reaction are distilled out. When the byproduct water and the ethylene glycol are completely distilled out, the reaction is complete, and the prepolymer of the copolyester is obtained.

(3) And (3) discharging the prepolymer obtained in the step (2) into a polycondensation kettle, adding 7450g of ethylene glycol antimony, gradually reducing the pressure and raising the temperature, enabling the pressure in a reaction system to be 50Pa, enabling the reaction end point temperature to be 275 ℃, and reacting for 4.8 hours to obtain the (terephthalic acid-isosorbide-ethylene glycol-1, 4-cyclohexanedimethanol) copolyester with high molecular weight.

The copolyester was characterized to have an intrinsic viscosity of 0.81 dL/g. The random copolyester had a Tg of 105 ℃ as determined by DSC.

EXAMPLE 6 efficient preparation of high Heat resistant high Performance copolyester of terephthalic acid-isosorbide-ethylene glycol-1, 3-cyclohexanedimethanol by semi-continuous Process

(1) Under the protection of nitrogen atmosphere, 2490kg (15000mol) of terephthalic acid and 1860kg (30000mol) of ethylene glycol (the molar ratio of the terephthalic acid to the ethylene glycol is 1: 3) are added into a first esterification kettle, the pressure is increased to 280kPa, the reaction is stirred at 255 ℃ for 3.8 hours, and the water generated as a byproduct of the reaction is distilled out. When the byproduct water is completely evaporated, the reaction is complete, and terephthalic acid and glycol ester compounds are obtained; 2/3 esterified substance was discharged into the second esterification vessel, and 1660kg (10000mol) of terephthalic acid and 1240kg (20000mol) of ethylene glycol mixture were added into the first esterification vessel at a rate of 1000kg/min to continue the esterification reaction with the remaining esterified substance.

(2) 830k g (5000mol) of terephthalic acid, 124kg (2000mol) of ethylene glycol, 1440kg (10000mol) of isosorbide, 1022kg (7000mol) of 1, 3-cyclohexanedimethanol and 890g of zinc oxide are added into the esterification product in the second esterification kettle in the step (1), the second esterification reaction/ester exchange reaction is carried out for 3.5 hours under the condition of normal pressure and 200 ℃, and the by-product water and ethylene glycol generated by the reaction are distilled out. When the byproduct water and the ethylene glycol are completely distilled out, the reaction is complete, and the prepolymer of the copolyester is obtained.

(3) And (3) discharging the prepolymer obtained in the step (2) into a polycondensation kettle, adding 860g of silicon dioxide/titanium dioxide compound, gradually reducing the pressure and raising the temperature, enabling the pressure in a reaction system to be 50Pa, enabling the reaction end point temperature to be 280 ℃, and reacting for 4 hours to obtain the high-molecular-weight (terephthalic acid-isosorbide-ethylene glycol-1, 3-cyclohexanedimethanol) copolyester.

The copolyester was characterized to have an intrinsic viscosity of 0.72 dL/g. The random copolyester had a Tg of 110 ℃ as determined by DSC.

The isosorbide modified PET prepared by the embodiment has excellent heat resistance and outstanding comprehensive performance, can be used for preparing materials such as polymer alloys, heat-resistant containers, fibers, films, sheets, optical products and the like, and can also be used in the fields of food packaging, electronic components, automobile parts, medical materials and the like.

Comparative example 1

Experimental groups: preparation of polyester Using the procedure of example 1

Control group: the same proportion of terephthalic acid and dihydric alcohol as that in example 1 is adopted, 125g of antimony trioxide is only added in the catalyst, no zinc acetate is added, the pressure esterification is carried out for 6h under the conditions of 350kPa and 250 ℃, and then the melt polycondensation is carried out for 6h under the conditions of 80Pa and 280 ℃ to prepare the heat-resistant polyester. The results are shown in the following table:

TABLE 1 comparison of the parameters of comparative example 1 experimental group and control group

Serial number	Conversion of isosorbide	Residual amount of metal	Glass transition temperature	Intrinsic viscosity number
					Experimental group	92％	0.0056mol/kg	107℃	0.85dL/g
Control group	55％	0.0092mol/kg	96℃	0.76dL/g

As shown in Table 1, the isosorbide conversion, metal residue, glass transition temperature and intrinsic viscosity of the experimental group were all superior to those of the control group.

Comparative example 2

Experimental groups: preparation of polyester Using the procedure of example 1

Control group: the corresponding polyester was prepared by the method of example 1 without the addition of 1,4:3, 6-dianhydro-hexanehexol and mixtures thereof. The results are shown in the following table:

TABLE 2 comparison of the Performance of the experimental group and the control group of comparative example 2

Serial number	Tensile strength	Glass transition temperature	Transmittance of light
				Experimental group	62MPa	107℃	91％
Control group	50MPa	79℃	82％

As shown in table 2, the experimental group is superior to the control group in mechanical properties, thermodynamic properties, and optical properties.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.