Production method of polyaromatic-carbonic acid-aliphatic copolyester

Abstract

The invention belongs to the technical field of polymer materials, and particularly relates to a polyaromatic-carbonic acid-aliphatic copolyester production method which comprises the following steps: mixing aromatic dibasic acid and aliphatic dihydric alcohol, feeding into a first esterification kettle, and adding an esterification catalyst for esterification reaction to obtain an esterification product; uniformly mixing aliphatic dihydric alcohol, feeding the mixture into a second esterification kettle, adding diester carbonate and a transesterification catalyst into the second esterification kettle, reacting to obtain a transesterification product, and feeding the transesterification product into a demonomerisation kettle to obtain a demonomerisation product; mixing the esterification product and the demonomerisation product with a polycondensation catalyst and a stabilizer, shearing and homogenizing, feeding into a pre-polycondensation kettle for reaction to obtain a pre-polycondensation product, feeding the pre-polycondensation product into a final polycondensation kettle for reaction to obtain a copolymer, and performing water-cooling granulation to obtain a copolyester product. According to the production method provided by the invention, the final polycondensation time can be shortened, and the weight-average molecular weight and the mechanical strength of the prepared copolyester are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polymer materials, and particularly relates to a production method of a polyaromatic-carbonate-aliphatic copolyester. BACKGROUND

[0002] With the increasing attention to environmental protection, degradable plastics have been more and more widely used. Among them, polybutylene adipate terephthalate (PBAT) is a widely recognized degradable plastic, which has excellent comprehensive performance and can be used in the fields of blown film bag making, injection molding and the like. However, PBAT has poor barrier property and low mechanical strength, which limits its application and development in the packaging field.

[0003] Aliphatic polycarbonates are also a kind of degradable plastics with excellent degradation performance, and have good hydrolysis resistance, excellent flexibility and low water vapor permeability. In comparison, the transesterification method uses carbonic diester and aliphatic diol (or polyol) as raw materials for synthesis, and has the advantages of wide raw material sources, diverse structures and green environmental protection. Patent No. CN112280028A reports a preparation method of high molecular weight polybutylene carbonate (abbreviated as PBC, which belongs to aliphatic polycarbonates), but the melting point of polybutylene carbonate is relatively low, usually at 40-60℃, and the crystallization speed is also relatively slow (the high molecular weight PBC melt cooling crystallization time can be as long as 1h), which greatly limits its application.

[0004] At present, many researchers have conducted in-depth research on the structure-activity relationship of aromatic-aliphatic polycarbonates. Patent CN103265689A introduces aromatic monomers such as terephthalic acid and isophthalic acid into the polycarbonate main chain, and uses a step-by-step esterification method to prepare a polyaromatic-carbonate-aliphatic copolyester with excellent performance, and explores the influence of ester exchange catalysts such as metal hydroxides, metal oxides, alkoxide metal compounds, metal carbonates, metal bicarbonates, metal halides, metal acetates, organic acids, tin-based organic compounds and titanium-based organic compounds on the molecular weight of the product. However, the final polycondensation time of the copolyester obtained by this method is relatively long, about 20h, which will face the problem of high energy consumption in large-scale industrial production, and the production cost is high and the economy is poor. Therefore, how to further simplify the production steps of the polyaromatic-carbonate-aliphatic copolyester, shorten the polymerization time, improve the product yield, reduce the consumption of raw materials, and provide a copolymer with better performance is an urgent technical problem to be solved. SUMMARY

[0005] In view of the technical problems of long final polycondensation time and poor performance in the prior art polycondensation method of copolyesters mentioned in the background art, the application provides a production method of polyaromatic-carbonate-aliphatic copolyesters, which can shorten the final polycondensation reaction time and improve the weight average molecular weight and mechanical strength of the prepared copolyesters through innovative production process.

[0006] The application provides a production method of polyaromatic-carbonate-aliphatic copolyesters, which comprises the following steps: S1, mixing and preparing aromatic diacid and aliphatic diol into uniform slurry, feeding into a first esterification kettle and adding esterification catalyst to perform esterification reaction to obtain esterification product, the molar ratio of aromatic diacid to aliphatic diol in the uniform slurry is 1:1.5-1:3; S2, feeding the uniformly mixed aliphatic diol into a second esterification kettle, adding carbonic acid diester and ester exchange catalyst into the second esterification kettle to perform ester exchange reaction to obtain ester exchange product, feeding the ester exchange product into a monomer removal kettle to remove small molecules and oligomer products to obtain monomer removal product, the molar ratio of carbonic acid diester to aliphatic diol is 1.5:1-3:1, the content of carbonic acid diester in the second esterification kettle during ester exchange reaction is 20-80% of distillate, and the carbonic acid diester is added in batches; S3, mixing the esterification product obtained in S1 and the monomer removal product obtained in S2 with polycondensation catalyst and stabilizer, feeding into a pre-polycondensation kettle after shearing and homogenization to obtain pre-polycondensation product, feeding the pre-polycondensation product into a final polycondensation kettle to perform reaction to obtain copolymer, feeding the copolymer into a tackifier kettle or a dynamic mixing reactor to perform reaction and then water cooling and granulation to obtain copolyester product.

[0007] Further, the aliphatic diol comprises one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2,4-trimethyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-tert-butyl-1,3-propanediol, and 2,2,4-trimethyl-1,6-hexanediol; The carbonic acid diester comprises one or more of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, diphenyl carbonate, ditolyl carbonate, and dinaphthyl carbonate. The aromatic diacid comprises one or more of terephthalic acid, naphthalene ring dimethyl acid, furan dimethyl acid, and six-membered ring dimethyl acid.

[0008] Further, the esterification catalyst and the ester exchange catalyst comprise one or more of acetate, titanium-based compounds, antimony-based compounds, germanium-based compounds, and rare earth compounds. The polycondensation catalyst comprises one or more of titanium-based compounds, antimony-based compounds, germanium-based compounds, tin-based compounds and rare earth compounds; The stabilizer comprises one or several mixtures of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, tripropyl phosphite, triphenyl phosphite, phosphorous acid or phosphoric acid.

[0009] Further, the amount of the esterification catalyst in step S1 is 0.001-5wt% of the sum of the mass of the aromatic dibasic acid and the aliphatic dihydric alcohol; the reaction temperature of the first esterification kettle is 160-250℃, the pressure is 10-30kPa, and the reaction time is 1-10h.

[0010] Further, the amount of the esterification catalyst in step S2 is 0.001-5wt% of the sum of the mass of the dimethyl carbonate and the aliphatic dihydric alcohol; the reaction temperature of the second esterification kettle is 90-200℃, the reaction time is 1-30h, the content of the carbonic acid diester in the ester exchange reaction process of the second esterification kettle is 20-80% of the reactants; the reaction temperature of the monomer removal kettle is 120-200℃, the pressure is 10-70kPa, and the reaction time is 0-6h.

[0011] Further, the amount of the polycondensation catalyst in step S3 is 0.005-5wt% of the sum of the weight of the monomer removal product and the esterification product, and the amount of the stabilizer is 0.001-1wt% of the sum of the weight of the monomer removal product and the esterification product; the reaction temperature of the pre-polycondensation kettle is 160-230℃, the pressure is 70-90kPa, and the reaction time is 2-8h; the reaction temperature of the final polycondensation kettle is 180-230℃, the pressure is 90-99kPa, and the reaction time is 0-8h.

[0012] Further, the reaction temperature of the tackifier kettle in step S3 is 180-230℃, the pressure is 5-1000Pa, and the reaction time is 0-8h; the reaction temperature of the dynamic mixing reactor is 160-240℃, the pressure is 90-100kPa, and the residence time is 0-60min.

[0013] The present application has the following advantages: 1. The present application increases the reaction process of the monomer removal kettle, which can better remove the small molecular oligomers and other polymers generated in the esterification reaction process, improve the esterification rate, and is beneficial to adjust the molecular structure and distribution of the esterification, and is beneficial to synthesize high molecular weight polymers, so that the molecular weight of the product reaches 88800g / moL. Meanwhile, the present application uses a tackifier reactor or a dynamic mixing reactor, which increases the devolatilization area, increases the molecular polymerization degree in a short time, and can make the product molecular weight reach 124900g / mol.

[0014] 2. The application adopts the method of adding carbonic acid diester into aliphatic diol in batches to reduce the consumption of carbonic acid diester raw material, which is conducive to the forward reaction and the synthesis of high molecular weight polymer. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The step block diagram of the production method of polyaromatic-carbonate-aliphatic copolyester in Example 1 of the application; Figure 2 The step block diagram of the production method of polyaromatic-carbonate-aliphatic copolyester in Example 2 of the application; Figure 3 The step block diagram of the production method of polyaromatic-carbonate-aliphatic copolyester in Example 3 of the application. DETAILED DESCRIPTION

[0016] The specific embodiments of the application will be described in detail below with reference to specific drawings. It should be noted that the technical features described in the following examples or combinations of technical features should not be considered in isolation, and they can be combined with each other to achieve better technical effects.

[0017] The application provides a production method of polyaromatic-carbonate-aliphatic copolyester, wherein the production device used in the production method is shown in FIG. Figure 1 3, which includes a first slurry tank, a second slurry tank, a first esterification kettle, a second esterification kettle, a single removal kettle, a pre-polycondensation kettle, a final polycondensation kettle, a thickening kettle and a dynamic mixing reactor. The first slurry tank is connected to the first esterification kettle through a pipeline, and the second slurry tank is connected to the second esterification kettle and the single removal kettle through a pipeline in sequence. In the application, the esterification kettle adopts a reflux rectifying column, which can adjust the ratio of carbonic acid diester and aliphatic diol, efficiently utilize raw materials, adjust the molecular configuration and distribution, synthesize high molecular weight polymer, reduce the yield of by-products, improve the yield of products, optimize the esterification process and save energy and reduce consumption.

[0018] The discharge outlets of the first esterification kettle and the single removal kettle are connected to the pre-polycondensation kettle through a conveying pipeline, and an injection system and a shear homogenizing mixer are arranged on the conveying pipeline. The injection system is used to inject polycondensation catalyst and stabilizer, and the shear homogenizing mixer is used to overcome the shortcoming of short residence time of added oligomers and additives in the pipeline, so as to ensure sufficient mixing time of the additives and the oligomers. In the application, the shear homogenizing mixer is a high-shear homogenizing pump dynamic mixer or a homogenizer static mixer or a combination of the two.

[0019] The pre-polycondensation kettle is connected to the final polycondensation kettle through a pipeline, and the single removal kettle, the pre-polycondensation kettle and the final polycondensation kettle are further connected to a vacuum system for adjusting the vacuum degree during the reaction. In the application, the final polycondensation kettle adopts a horizontal membrane drawing reactor, which effectively increases the devolatilization area, is conducive to the removal of small molecular substances and the synthesis of good phase products with medium and high molecular weight.

[0020] The present application can adjust the molecular weight of the copolyester according to the copolyester to be prepared, such as the device shown in the accompanying drawings Figure 1 In one way, the terminal polycondensation kettle is connected with an underwater pelletizing system, and the copolyester product can be directly produced, and the weight average molecular weight of the copolyester product is 70000-90000 g / mol.

[0021] In one way, the terminal polycondensation kettle is connected with an underwater pelletizing system, and the copolyester product can be directly produced, and the weight average molecular weight of the copolyester product is 70000-90000 g / mol. Figure 2 Or in one way, the discharge port of the terminal polycondensation kettle is connected with a tackifying kettle or a dynamic mixing reactor, and the underwater pelletizing system is further arranged behind the tackifying kettle or the dynamic mixing reactor, and the weight average molecular weight of the produced copolyester product is 110000-130000 g / mol. Figure 3

[0022] The present application provides a production method of polyaromatic-carbonate-aliphatic copolyester, comprising the following steps: S1, mixing and preparing aromatic diacid, aliphatic diol and esterification catalyst into uniform slurry, and sending into the first esterification kettle for esterification reaction to obtain esterification product; Specifically, the raw materials of aromatic diacid and aliphatic diol are weighed according to the molar ratio of 1:1-1:3, and then added into the first slurry tank, and then the esterification catalyst with a total weight of 0.001-5wt% of the raw materials of aromatic diacid and aliphatic diol is weighed and added into the first slurry tank, and then mixed and prepared into uniform slurry, and then sent into the first esterification kettle for reaction. The reaction temperature of the first esterification kettle is set to 160-250℃, the pressure is set to 10-30kPaA, and the reaction is continuously carried out for 1-10h to obtain the esterification product.

[0023] In the present application, the aliphatic diol includes one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2,4-trimethyl-1,5-pentanediol, 2,2-dimethyl-1,3-propylene glycol, 2-ethyl-2-tert-butyl-1,3-propylene glycol, and 2,2,4-trimethyl-1,6-hexanediol. The aromatic diacid includes terephthalic acid, naphthalene dicarboxylic acid, furan dicarboxylic acid, and six-membered ring dicarboxylic acid.

[0024] ​The esterification catalyst includes one or more of acetate, titanium-based compound, antimony-based compound, germanium-based compound and rare earth compound, wherein the acetate is one or more of cobalt acetate, manganese acetate, magnesium acetate, calcium acetate, zinc acetate, lithium acetate, aluminum acetate and sodium acetate; the titanium-based compound is one or more of n-butyl titanate, isopropyl titanate, titanium dioxide, tetraisooctyl titanate, potassium titanium oxalate and titanium glycolate; the antimony-based compound is one or more of antimony trioxide, antimony acetate and antimony glycolate; the germanium-based compound is one or both of germanium dioxide and germanium chloride; the tin-based compound is one or more of stannous octoate, stannous oxalate, butyl tin acid, monobutyl tin oxide and dibutyl diethyl octanoate; and the rare earth compound is one or more of lanthanum chloride, hafnium chloride, rubidium chloride, yttrium chloride, lanthanum acetylacetone, hafnium acetylacetone, rubidium acetylacetone and yttrium acetylacetone.

[0025] S2, the esterification catalyst is mixed uniformly with the aliphatic diol and then sent to a second esterification kettle, carbonic acid diester is added to the second esterification kettle for ester exchange reaction, and an ester exchange product is obtained, the ester exchange product is sent to a monomer removal kettle for removal of small molecules and oligomerization products, and a monomer removal product is obtained; Specifically, the raw material carbonic acid diester and the aliphatic diol are weighed according to a molar ratio of 1:1.5-3:1, the aliphatic diol is sent to a second slurry tank, 0.001-5wt% of the ester exchange catalyst based on the total weight of the raw material carbonic acid diester and the aliphatic diol is weighed and added to the second slurry tank, and then mixed uniformly and sent to the second esterification kettle. The reaction temperature of the second esterification kettle is set to 90-200℃, the reaction pressure is normal pressure, carbonic acid diester is added to the second esterification kettle in batches during the reaction, and the content of carbonic acid diester in the second esterification kettle during the ester exchange reaction is controlled to be 20-80% of the total reactant mass, so as to facilitate the forward reaction. After the reaction is completed, the ester exchange product is obtained, the ester exchange product is sent to the monomer removal kettle for removal of small molecules and oligomerization products, the reaction temperature of the monomer removal kettle is set to 120-200℃, the reaction pressure is 10-70kPa, and the reaction time is 0-6h. After the reaction is completed, the monomer removal product is obtained.

[0026] In the present application, the aliphatic diol is the same as in step S1, the ester exchange catalyst is the same as the esterification catalyst described in step S1, and the carbonic acid diester includes one or more of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, diphenyl carbonate, dimethylphenyl carbonate and dinaphthyl carbonate.

[0027] S3, the esterification product obtained in S1 and the monomer removal product obtained in S2 are mixed with a polycondensation catalyst and a stabilizer, and then sent to a pre-polycondensation kettle after shearing and homogenization to obtain a pre-polycondensation product, the pre-polycondensation product is sent to a final polycondensation kettle for reaction to obtain a copolymer, and the copolymer is directly water-cooled and pelletized or sent to a tackifying kettle and / or a dynamic mixing reactor for reaction and then water-cooled and pelletized to obtain a copolyester product.

[0028] Specifically, the esterification product and the depolymerization product are input into a pre-polycondensation kettle through a conveying pipeline, and a polycondensation catalyst and a stabilizer are added in the conveying pipeline, wherein the amount of the polycondensation catalyst is 0.005-5wt% of the total weight of the depolymerization product and the esterification product, and the amount of the stabilizer is 0.001-1wt% of the total weight of the depolymerization product and the esterification product. The esterification product, the depolymerization product, the polycondensation catalyst and the stabilizer in the conveying pipeline pass through a shearing homogenizing mixer, the shearing speed of the shearing homogenizing mixer is 300-3000rad / s, and the shearing time is 5-60s. The pre-polycondensation product is obtained by entering the pre-polycondensation kettle for reaction. The shearing homogenizing mixer can make the raw materials and the catalyst and the stabilizer fully mixed and keep liquefaction without vaporization, so that the groups with various characteristics are uniformly distributed on the main chain of the polyester, the homogeneous plug flow reaction is more sufficient, and the high-quality copolyester product is ensured in the later period. The reaction temperature of the pre-polycondensation kettle is 160-230℃, the pressure is 70-90kPa, the reaction time is 2-8h, and the weight average molecular weight of the pre-polycondensation product is 30000-50000g / moL.

[0029] Then the pre-polycondensation product is sent into a final polycondensation kettle for continuous reaction to obtain the copolymer, the reaction temperature of the final polycondensation kettle is 180-230℃, the pressure is 90-99kPaA, and the reaction time is 0-8h.

[0030] After obtaining the copolymer, the copolymer is post-processed according to the product to obtain the copolyester product, the post-processing includes any one of direct water-cooling granulation and sending the copolymer into a tackifying kettle and / or a dynamic mixing reactor for reaction and then water-cooling granulation. The weight average molecular weight of the copolyester product obtained by direct water-cooling granulation is 70000-90000g / moL, and the weight average molecular weight of the copolyester product after the reaction of the tackifying kettle and / or the dynamic mixing reactor is 110000-130000g / moL. It should be noted that the chain extender needs to be added when the dynamic mixing reactor is added for reaction, and the chain extender is diisocyanate, diacid anhydride, diacyl chloride, bisepoxide, bisoxazoline, specifically including 1,6-hexane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene-1,6-diisocyanate, maleic anhydride, succinic anhydride, acetic anhydride, phthalic anhydride, benzene tetraanhydride, butanedioyl chloride, hexanedioyl chloride, sebacoyl chloride, ethylene oxide, propylene oxide, trihydroxypropane, and 2,2-bis(2-oxazoline).

[0031] The polycondensation catalyst in the application includes one or more of titanium-based compounds, antimony-based compounds, germanium-based compounds, tin-based compounds and rare earth compounds, and the specific compounds are the same as the esterification catalysts described above.

[0032] The stabilizer includes one or a mixture of several of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, tripropyl phosphite, triphenyl phosphite, phosphorous acid or phosphoric acid.

[0033] Example 1 The present embodiment provides a method for producing a polyaromatic-carbonate-aliphatic copolyester, comprising the following steps: S1, terephthalic acid (PTA) and 1,4-butanediol (BDO) are prepared into a mixed slurry in a first slurry preparation tank according to a molar ratio of 1:1.8, and are fed into a first esterification kettle at a rate of 560 kg / h, zinc acetate catalyst is added into the first esterification kettle at a rate of 1.5 kg / h, the temperature of the first esterification kettle is controlled at 200°C, the pressure is 20 kPa, the reaction stays for 6 h, the water produced in the reaction is removed, and an esterification product is obtained.

[0034] S2, BDO and dimethyl carbonate (DMC) are weighed according to a molar ratio of 1:2.5, the BDO is mixed in a second slurry preparation tank and then fed into a second esterification kettle at a rate of 340 kg / h, the DMC is added into the second esterification kettle in several portions and magnesium acetate catalyst is added into the second esterification kettle at a rate of 1 kg / h, the reaction temperature of the second esterification kettle is controlled at 160°C, the reaction pressure is normal pressure, the reaction stays for 20 h, and the DMC content in the azeotrope of the second esterification kettle is kept at 20% to 80% during the reaction. An ester exchange product is obtained by the reaction, and the ester exchange product is continuously fed into a unification removal kettle, the reaction temperature in the unification removal kettle is controlled at 180°C, the pressure is 30 kPaA, and the reaction stays for 2 h to obtain a unification removal product.

[0035] S3, the esterification product and the unification removal product are continuously fed into a pre-polycondensation kettle through a conveying pipeline at a rate of 560 kg / h and 340 kg / h respectively, and antimony glycol and triphenyl phosphite stabilizer are injected into the conveying pipeline at a rate of 0.2 kg / h. The esterification product, the unification removal product, the antimony glycol and the triphenyl phosphite stabilizer are fed into the pre-polycondensation kettle after passing through a high-shear homogenizing pump, the temperature in the pre-polycondensation kettle is set at 180°C, the pressure is 90 kPa, and the pre-polycondensation reaction stays for 3 h to obtain a pre-polycondensation product, which is then fed into a final polycondensation kettle, the temperature in the final polycondensation kettle is 200°C, the pressure is 200 Pa, and the reaction stays for 8 h to obtain a copolymer melt, which is then fed into a water-cooled pelletizing device to obtain a copolymer product, which is an injection molding grade chip.

[0036] Example 2 The present embodiment provides a method for producing a polyaromatic-carbonate-aliphatic copolyester, comprising the following steps: S1, terephthalic acid (PTA) and 1,2-butanediol are prepared into a mixed slurry in a first slurry preparation tank according to a molar ratio of 1:2.2, and are fed into a first esterification kettle at 560 kg / h, and zinc acetate catalyst is added into the first esterification kettle at 1.5 kg / h, the temperature of the first esterification kettle is controlled at 220 ℃, the pressure is 25 kPa, the reaction stays for 5 h, the water produced in the reaction is removed, and an esterification product is obtained.

[0037] S2, 1,2-butanediol and diethyl carbonate are weighed according to a molar ratio of 1:2.1, BDO is put into a second slurry preparation tank for mixing, and then is fed into a second esterification kettle at 340 kg / h, DMC is added into the second esterification kettle in batches, and magnesium acetate catalyst is added into the second esterification kettle at 1 kg / h, the reaction temperature of the second esterification kettle is controlled at 160 ℃, the reaction pressure is normal pressure, the reaction stays for 20 h, and the DMC content in the azeotrope of the second esterification kettle is kept at 20% to 80% during the reaction. The ester exchange product obtained in the reaction is continuously fed into a monomer removal kettle, the reaction temperature in the monomer removal kettle is controlled at 160 ℃, the pressure is 40 kPa, and the reaction stays for 3 h to obtain a monomer removal product.

[0038] S3, the esterification product and the monomer removal product are continuously fed into a pre-polycondensation kettle through a conveying pipeline at a speed of 560 kg / h and 340 kg / h respectively, and antimony glycol catalyst and triphenyl phosphite stabilizer are injected into the conveying pipeline at a speed of 0.2 kg / h. The esterification product, the monomer removal product, the antimony glycol catalyst and the triphenyl phosphite stabilizer are fed into the pre-polycondensation kettle after passing through a high-shear homogenizing pump, the temperature in the pre-polycondensation kettle is set at 180 ℃, the pressure is 90 kPa, and the polycondensation reaction stays for 3 h to obtain a pre-polycondensation product, which is then fed into a final polycondensation kettle, the temperature in the final polycondensation kettle is 200 ℃, the pressure is 200 Pa, and the reaction stays for 1.5 h to obtain a copolymer melt, which is then fed into a tackifying kettle, the pressure in the tackifying kettle is set at 50 Pa, the temperature is 200 ℃, and the copolymer melt is continuously tackified for 4 h to obtain a copolymer melt. After passing through a water-cooling granulating device, a copolymer product is obtained, which is a blow molding grade chip.

[0039] Example 3 The present embodiment provides a production method of a polyaromatic-carbonate-aliphatic copolyester, which comprises the following steps: S1, terephthalic acid and 1,4-butanediol are prepared into a mixed slurry in a first slurry preparation tank according to a molar ratio of 1:2.5, and are fed into a first esterification kettle at 560 kg / h, and zinc acetate catalyst is added into the first esterification kettle at 1.5 kg / h, the temperature of the first esterification kettle is controlled at 190 ℃, the pressure is 23 kPa, the reaction stays for 6 h, the water produced in the reaction is removed, and an esterification product is obtained.

[0040] S2, 1,4-butanediol and dimethyl carbonate (DMC) are weighed according to a molar ratio of 1:1.7, BDO is put into a second slurry preparation tank for mixing, and then is fed into a second esterification kettle at a rate of 340 kg / h, DMC is added into the second esterification kettle in batches, and magnesium acetate catalyst is added into the second esterification kettle at a rate of 1 kg / h, the reaction temperature of the second esterification kettle is controlled at 160 ℃, the reaction pressure is normal pressure, the reaction stays for 20 h, and the DMC content in the azeotrope of the second esterification kettle is kept at 20% to 80% during the reaction. The ester exchange product is continuously fed into a single-removal kettle, the reaction temperature in the single-removal kettle is controlled at 150 ℃, the pressure is 50 kPa, and the reaction stays for 3 h to obtain a single-removal product.

[0041] S3, the esterification product and the single-removal product are continuously fed into a pre-polycondensation kettle at a rate of 560 kg / h and 340 kg / h respectively through a conveying pipeline, and ethylene glycol antimony catalyst and triphenyl phosphite stabilizer are injected into the conveying pipeline at a rate of 0.2 kg / h. The esterification product, the single-removal product, and the ethylene glycol antimony catalyst and the triphenyl phosphite stabilizer pass through a high-shear homogenizing pump and then enter the pre-polycondensation kettle, the temperature in the pre-polycondensation kettle is set at 180 ℃, the pressure is 90 kPa, and the polycondensation reaction stays for 3 h to obtain a pre-polycondensation product, which is then fed into a final polycondensation kettle, the temperature in the final polycondensation kettle is 190 ℃, the pressure is 90 kPa, and the reaction stays for 2 h to obtain a copolymer melt, the copolymer melt is fed into a dynamic mixing reactor, a chain extender is added, the pressure in the dynamic mixing reactor is set at 100 kPa, the temperature is 190 ℃, and the continuous reaction stays for 4 h to obtain a copolymer melt. The copolymer product is obtained after passing through a water-cooling granulation device, and the product is a blow molding grade chip.

[0042] Comparative Example 1 The difference between this comparative example and Example 1 is that the reaction parameters are different, and specifically this comparative example includes the following steps: S1, terephthalic acid (PTA) and 1,4-butanediol (BDO) are prepared into a mixed slurry in a first slurry preparation tank according to a molar ratio of 1:1, and are fed into a first esterification kettle at a rate of 560 kg / h, zinc acetate catalyst is added into the first esterification kettle at a rate of 1.5 kg / h, the temperature of the first esterification kettle is controlled at 200 ℃, the pressure is 20 kPa, the reaction stays for 6 h, and the water in the reaction product is removed to obtain an esterification product.

[0043] S2, BDO and dimethyl carbonate (DMC) were weighed according to a molar ratio of 1:3.5, BDO was put into a second slurry tank for mixing, then was fed into a second esterification kettle at a rate of 340 kg / h, DMC was added into the second esterification kettle in batches and magnesium acetate catalyst was added into the second esterification kettle at a rate of 1 kg / h, the reaction temperature of the second esterification kettle was controlled at 160°C, the reaction pressure was normal pressure, and the reaction was stopped after 20 h. The ester exchange product was obtained by reaction, and was continuously fed into a single-removing kettle, the reaction temperature of the single-removing kettle was controlled at 180°C, the pressure was 30 kPa, and the reaction was stopped after 2 h to obtain a single-removed product.

[0044] S3, the esterification product and the single-removed product were continuously fed into a pre-polycondensation kettle at a rate of 560 kg / h and 340 kg / h respectively through a conveying pipeline, and antimony glycol and triphenyl phosphite stabilizer were injected into the conveying pipeline at a rate of 0.2 kg / h. The esterification product, the single-removed product, the antimony glycol and the triphenyl phosphite stabilizer were fed into the pre-polycondensation kettle after passing through a high-shear homogenizing pump, the temperature of the pre-polycondensation kettle was set at 180°C, the pressure was 90 kPa, and the pre-polycondensation reaction was stopped after 3 h to obtain a pre-polycondensation product, then the pre-polycondensation product was fed into a final polycondensation kettle, the temperature of the final polycondensation kettle was 200°C, the pressure was 200 Pa, and the reaction was stopped after 8 h to obtain a copolymer melt, then the copolymer melt was fed into a water-cooling granulation device to obtain a copolymer product, and the product was an injection molding grade chip.

[0045] Comparative Example 2 The difference between this comparative example and Example 1 is that the single-removing reaction step is not performed. The specific steps are as follows: The terephthalic acid (PTA) and 1,4-butanediol (BDO) are prepared into mixed slurry in a first slurry tank according to a molar ratio of 1:1.8, and fed into a first esterification kettle at a rate of 560 kg / h, and a zinc acetate catalyst is added into the first esterification kettle at a rate of 1.5 kg / h, the temperature of the first esterification kettle is controlled at 200 ℃, the pressure is 20 kPa, the reaction stays for 6 h, and the water produced in the reaction is removed to obtain an esterification product. The BDO and dimethyl carbonate (DMC) are weighed according to a molar ratio of 1:2.5, the BDO is mixed in a second slurry tank, and then fed into a second esterification kettle at a rate of 340 kg / h, the DMC is added into the second esterification kettle in batches, and a magnesium acetate catalyst is added into the second esterification kettle at a rate of 1 kg / h, the temperature of the second esterification kettle is controlled at 160 ℃, the reaction pressure is normal pressure, the reaction stays for 20 h, and the BDO content in the azeotrope of the second esterification kettle is kept at 20% to 80% during the reaction, and an ester exchange product is obtained. The esterification product and the ester exchange product are continuously fed into a pre-polycondensation kettle through a conveying pipeline at a rate of 560 kg / h and 340 kg / h respectively, and an antimony glycol catalyst and a triphenyl phosphite stabilizer are injected into the conveying pipeline at a rate of 0.2 kg / h. The esterification product, the single-removal product, the antimony glycol catalyst and the triphenyl phosphite stabilizer are fed into the pre-polycondensation kettle through a high-shear homogenizing pump, the temperature in the pre-polycondensation kettle is set at 180 ℃, the pressure is 90 kPa, and a pre-polycondensation product is obtained after the pre-polycondensation reaction for 3 h. The pre-polycondensation product is then fed into a final polycondensation kettle, the temperature in the final polycondensation kettle is 200 ℃, the pressure is 200 Pa, and a copolymer melt is obtained after the reaction for 10 h. The copolymer melt is then fed into a water-cooling granulation device to obtain a copolymer product, which is an injection-grade chip.

[0046] Comparative Example 3 The difference between this comparative example and Example 3 is that the esterification product, the single-removal product, the antimony glycol catalyst and the triphenyl phosphite stabilizer are directly fed into the pre-polycondensation kettle without being subjected to the high-shear homogenizing pump. The specific steps are as follows: The terephthalic acid (PTA) and 1,4-butanediol (BDO) are prepared into mixed slurry in a first slurry tank according to a molar ratio of 1:2.5, and fed into a first esterification kettle at a rate of 560 kg / h, and a zinc acetate catalyst is added into the first esterification kettle at a rate of 1.5 kg / h, the temperature of the first esterification kettle is controlled at 190 ℃, the pressure is 23 kPa, the reaction stays for 6 h, and the water produced in the reaction is removed to obtain an esterification product.

[0047] BDO and dimethyl carbonate (DMC) were weighed according to a molar ratio of 1:1.7, BDO was put into a second slurry preparation tank for mixing, then was put into a second esterification kettle at a rate of 340 kg / h, DMC was added into the second esterification kettle in batches, and magnesium acetate catalyst was added into the second esterification kettle at a rate of 1 kg / h, the reaction temperature of the second esterification kettle was controlled at 160 ℃, the reaction pressure was normal pressure, the reaction was stopped after 20 h, and the BDO content in the azeotrope of the second esterification kettle was kept at 20% to 80% during the reaction. The transesterification product was obtained by the reaction, and the transesterification product was continuously transported to a single-removal kettle, the reaction temperature in the single-removal kettle was controlled at 150 ℃, the pressure was 50 kPa, and the reaction was stopped after 3 h to obtain a single-removed product.

[0048] The esterification product and the single-removed product were continuously transported into a pre-polycondensation kettle through a conveying pipeline at a rate of 560 kg / h and 340 kg / h respectively, and antimony glycol and triphenyl phosphite stabilizer were injected into the conveying pipeline at a rate of 0.2 kg / h. The temperature in the pre-polycondensation kettle was set at 180 ℃, the pressure was 90 kPa, and the polycondensation reaction was stopped after 3 h to obtain a pre-polycondensation product. The pre-polycondensation product was transported into a final polycondensation kettle, the temperature in the final polycondensation kettle was 190 ℃, the pressure was 90 kPa, and the reaction was stopped after 5 h to obtain a copolymer melt. The copolymer melt was transported into a dynamic mixing reactor, and a chain extender was added. The pressure in the dynamic mixing reactor was set at 100 kPa, the temperature was 190 ℃, and the continuous reaction was stopped after 3 h to obtain a copolymer melt. The copolymer product was obtained after water cooling and granulation, and the product was a blow molding grade chip.

[0049] Comparative Example 4 The difference between this comparative example and Example 3 is that the content of the carbonic acid diester in the azeotrope of the second esterification kettle is not controlled at 20% to 80% in step S2. The specific steps are as follows: Terephthalic acid (PTA) and 1,4-butanediol (BDO) were prepared into a mixed slurry in a first slurry preparation tank according to a molar ratio of 1:1.8, were put into a first esterification kettle at a rate of 560 kg / h, and zinc acetate catalyst was added into the first esterification kettle at a rate of 1.5 kg / h. The temperature in the first esterification kettle was controlled at 190 ℃, the pressure was 23 kPa, and the reaction was stopped after 6 h to remove the reaction product water and obtain an esterification product.

[0050] BDO and dimethyl carbonate (DMC) were weighed according to a molar ratio of 1:2.5, BDO was put into a second slurry preparation tank for mixing, then was put into a second esterification kettle at a rate of 340 kg / h, DMC was added into the second esterification kettle at one time, and magnesium acetate catalyst was added into the second esterification kettle at a rate of 1 kg / h. The reaction temperature of the second esterification kettle was controlled at 160 ℃, the reaction pressure was normal pressure, and the reaction was stopped after 20 h. The transesterification product was obtained by the reaction, and the transesterification product was continuously transported to a single-removal kettle, the reaction temperature in the single-removal kettle was controlled at 150 ℃, the pressure was 50 kPa, and the reaction was stopped after 3 h to obtain a single-removed product.

[0051] The esterification product and the depolymerization product are continuously fed into the pre-polycondensation kettle at a speed of 560 kg / h and 340 kg / h respectively through the conveying pipe, and the antimony glycol catalyst and the triphenyl phosphite stabilizer are injected into the conveying pipe at a speed of 0.2 kg / h. The esterification product, the depolymerization product, and the antimony glycol catalyst and the triphenyl phosphite stabilizer pass through the high-shear homogenizing pump and enter the pre-polycondensation kettle, and the temperature in the pre-polycondensation kettle is set to 180°C, and the pressure is 90 kPa. After 3 h of polycondensation reaction, the pre-polycondensation product is obtained, and then the pre-polycondensation product is fed into the final polycondensation kettle, the temperature in the final polycondensation kettle is 190°C, and the pressure is 90 kPa. After 5 h of reaction, the copolymer melt is obtained, and then the copolymer melt is fed into the dynamic mixing reactor, and then the chain extender is added. The pressure in the dynamic mixing reactor is set to 100 kPa, and the temperature is 190°C. After 3 h of continuous reaction, the copolymer melt is obtained. After passing through the water-cooled granulation equipment, the copolymer product is obtained, which is a blow molding grade chip.

[0052] The copolyester chips prepared in the examples and comparative examples are subjected to basic performance testing and barrier performance testing, and the results are shown in Tables 1-2 below. The test conditions for biodegradation rate are under the conditions of industrial composting, and the degradation period is 4 months. Other performances are detected according to industry standards. The barrier performance test is detected according to the method of national standard GB / T 1038.1-2022.

[0053] Table 1 Basic performance test table of copolyester products of examples and comparative examples Analysis of experimental results: The weight average molecular weight of the copolyester prepared in the examples of the present application is 88,800 g / mol or more, and can be as high as 124,900 g / mol, which is much higher than that of the copolyester prepared in the comparative examples and the prior art. At the same time, the tensile strength and melting point of the copolyester prepared in the examples are higher than those of the copolyester prepared in the comparative examples, which has better performance and can be more widely applied in the field of high-end packaging.

[0054] Comparative example 1 changes the raw material ratio compared with example 1, and the weight average molecular weight and tensile strength decrease significantly compared with example 1. The reason is that after changing the ratio of carbonic acid diester and aliphatic dihydric alcohol, the side reaction increases, the molecular configuration of the ester exchange product changes, and the weight average molecular weight of the finally synthesized copolyester product decreases.

[0055] Comparative example 2 does not carry out depolymerization reaction, and does not remove small molecular polymers and oligomers generated in the esterification process, which reduces the molecular configuration and distribution of the copolyester in the subsequent polycondensation reaction, and is not conducive to the synthesis of copolyester with high molecular weight.

[0056] Comparative Example 3 did not perform high-speed shearing homogenization before polycondensation, and the high-speed shearing homogenization in the present application can increase the residence time of the catalyst, stabilizer, esterification product and single-removing product in the pipeline, and ensure that all raw materials are mixed uniformly before entering the pre-polycondensation reaction through high-speed shearing homogenization.

[0057] Comparative Example 4 did not control the proportion of carbonic acid diester in the distillate, and the specific reason was that all the carbonic acid diester was added at once when the raw materials were added, which hindered the ester exchange reaction to proceed in the positive direction. The present inventors found in the experimental process that by adding carbonic acid diester in batches, the reaction could be greatly promoted to proceed in the positive direction, not only reducing the side reaction, but also reducing the amount of carbonic acid diester raw materials added, and finally the performance of the copolyester prepared could be greatly improved. The best is to add in three times, so that the proportion of carbonic acid diester in the distillate is best during the reaction, and the reaction proceeds most quickly.

[0058] Table 2 Barrier property test table of copolyester products prepared in examples and comparative examples From the above experimental results, it can be seen that the copolyester material prepared by the present application is better than the copolyester material prepared by the comparative example in gas barrier property. Thanks to the larger weight average molecular weight of the copolyester prepared by the present application, the material internal structure is more dense, which can effectively block various gas molecules, and significantly widens the application scenarios of the copolyester prepared by the present application.

[0059] Although several embodiments of the present application have been given in the present text, those skilled in the art should understand that the embodiments in the present text can be changed without departing from the spirit of the present application. The above examples are only exemplary, and the embodiments in the present text should not be used as a limitation of the scope of the present application.

Claims

1. A method for producing a polyaromatic-carbonate-aliphatic copolyester, characterized by, The method comprises the following steps: S1, mixing aromatic diacid and aliphatic diol to prepare a uniform slurry, feeding the slurry into a first esterification kettle, and adding an esterification catalyst to perform esterification reaction to obtain an esterification product, wherein the molar ratio of aromatic diacid to aliphatic diol in the uniform slurry is 1:1.5-1:3; S2, feeding the mixed aliphatic diol into a second esterification kettle, adding a carbonic acid diester and an ester exchange catalyst to perform ester exchange reaction to obtain an ester exchange product, feeding the ester exchange product into a monomer removal kettle to remove small molecules and oligomer products to obtain a monomer removal product, wherein the molar ratio of carbonic acid diester to aliphatic diol is 1.5:1-3:1, the content of carbonic acid diester in the second esterification kettle during ester exchange reaction is 20-80% of the total reaction mass, and the carbonic acid diester is added in batches; S3, mixing the esterification product obtained in S1 and the monomer removal product obtained in S2 with a polycondensation catalyst and a stabilizer, shearing and homogenizing, feeding into a pre-polycondensation kettle to obtain a pre-polycondensation product, feeding the pre-polycondensation product into a final polycondensation kettle to obtain a copolymer, and directly water-cooling and granulating the copolymer or feeding the copolymer into a tackifying kettle and / or a dynamic mixing reactor to react and then water-cooling and granulating to obtain a copolyester product.

2. The method for producing a polyaromatic-sebacic-aliphatic copolyester according to claim 1, wherein The aliphatic diol in steps S1 and S2 comprises one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2,4-trimethyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-tert-butyl-1,3-propanediol, and 2,2,4-trimethyl-1,6-hexanediol; The carbonic acid diester comprises one or more of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, diphenyl carbonate, ditolyl carbonate, and dinaphthyl carbonate; The aromatic diacid comprises one or more of terephthalic acid, naphthalene dicarboxylic acid, furan dicarboxylic acid, and six-membered ring dicarboxylic acid.

3. The method of producing a poly (aromatic-carbonate-aliphatic) copolyester according to claim 1, wherein The esterification catalyst and the ester exchange catalyst comprise one or more of acetate, titanium-based compounds, antimony-based compounds, germanium-based compounds, and rare earth compounds; The polycondensation catalyst comprises one or more of titanium-based compounds, antimony-based compounds, germanium-based compounds, tin-based compounds, and rare earth compounds; The stabilizer comprises one or more of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, tripropyl phosphite, triphenyl phosphite, phosphorous acid, and phosphoric acid.

4. The method of producing a poly (aromatic-carbonate-aliphatic) copolyester according to claim 1, wherein The amount of the esterification catalyst in step S1 is 0.001-5wt% of the sum of the mass of aromatic diacid and aliphatic diol; the reaction temperature of the first esterification kettle is 160-250℃, the pressure is 10-30kPa, and the reaction time is 4-10h.

5. The method of producing a poly (aromatic-carbonate-aliphatic) copolyester according to claim 1, wherein The amount of the esterification catalyst used in step S2 is 0.001-5 wt% of the sum of the mass of dimethyl carbonate and the aliphatic dihydric alcohol; the reaction temperature of the second esterification kettle is 90-200°C, and the reaction time is 10-30 h; the reaction temperature of the monomer removal kettle is 120-200°C, the pressure is 10-70 kPa, and the reaction time is 1-6 h.

6. The method of producing a poly (aromatic-carbonate-aliphatic) copolyester according to claim 1, wherein The amount of the polycondensation catalyst used in step S3 is 0.005-5 wt% of the sum of the weight of the monomer removal product and the esterification product, and the amount of the stabilizer is 0.001-1 wt% of the sum of the weight of the monomer removal product and the esterification product; the reaction temperature of the pre-polycondensation kettle is 160-230°C, the pressure is 70-90 kPa, and the reaction time is 2-8 h; the reaction temperature of the final polycondensation kettle is 180-230°C, the pressure is 90-99 kPa, and the reaction time is 4-8 h.

7. The method for producing a poly (aromatic-carbonate-aliphatic) copolyester according to Claim 1, wherein The reaction temperature of the tackifying kettle in step S3 is 180-230°C, the pressure is 5-1000 Pa, and the reaction time is 0-8 h; the reaction temperature of the dynamic mixing reactor is 160-240°C, the pressure is 90-100 kPa, and the residence time is 0-60 min.

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