Semi-aromatic polyester and its preparation method and application

Abstract

The present invention discloses a semi-aromatic polyester and its preparation method and application. By controlling the hydroxyl content in the semi-aromatic polyester, in particular by controlling the content of hydroxyl groups bonded to aliphatic dicarboxylic acids in the semi-aromatic polyester to 17-40 mmol / kg, in particular by controlling the content of hydroxyl groups bonded to aromatic dicarboxylic acids in the semi-aromatic polyester to 17-40 mmol / kg, and by controlling the total content of hydroxyl groups to 35-80 mmol / kg, the compatibility of the semi-aromatic polyester with materials such as polylactic acid can be significantly improved, and thus a film material with high strength and tear resistance can be obtained.

Description

[Technical Field]

[0001] The present invention relates to the field of biodegradable polyesters, and more particularly to semi-aromatic polyesters having specific hydroxyl group contents and their preparation methods and applications. [Background technology]

[0002] Thermoplastic aromatic polyesters, now widely used in industry and daily life, have excellent thermal stability and mechanical properties, and are easy to process and inexpensive. For example, polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) are already widely used in the production of fibers, films, and containers. However, these aromatic polyesters are difficult to decompose after use and disposal, and no clear direct degradation of aromatic polyesters such as PET and PBT by microorganisms has been observed to date. To combine the excellent properties of aromatic polyesters, researchers have been studying the synthesis of aliphatic-aromatic copolyesters, i.e., the introduction of aromatic segments into aliphatic polyesters, since the 1980s.

[0003] PBAT is a representative aromatic polyester, but its tensile strength and elastic modulus are low. The lack of mechanical strength limits the application of PBAT, and it needs to be modified.

[0004] Polylactic acid (PLA) is an aliphatic polyester obtained by biological fermentation and chemical synthesis from biobased raw materials such as potato, cassava, and corn starch. It has good biocompatibility and biodegradability, as well as excellent mechanical strength, transparency, and processability, making it widely used in fields such as medicine, packaging films, and disposable daily necessities. However, its high brittleness and poor toughness make it difficult to popularize and apply in many fields.

[0005] Because PBAT and PLA exhibit completely different mechanical properties, they are often mixed and modified as complementary materials. That is, PLA is used as the matrix and PBAT is used to reinforce the modified polylactic acid, or PBAT is used as the matrix and PLA is used to reinforce the modified PBAT. The final modification effect depends on the compatibility of the two. However, due to the poor compatibility between PBAT and polylactic acid, these toughening modifiers can only slightly increase the impact strength of PLA, and it is often difficult to simultaneously increase the ductility of PLA. Summary of the Invention

[0006] In order to solve the above problems, the present invention aims to provide a semi-aromatic polyester, which has a specific hydroxyl group content, which can significantly improve the compatibility of the semi-aromatic polyester with materials such as polylactic acid, thereby obtaining a film material with high strength and tear resistance.

[0007] Another object of the present invention is to provide a method for preparing the semi-aromatic polyester.

[0008] The above object of the present invention is achieved by the following technical solutions.

[0009] A semi-aromatic polyester, Based on the total molar amount of the first component A, a1) 40 to 60 mol % of at least one aliphatic dicarboxylic acid or a derivative thereof; a2) a first component A containing 40 to 60 mol% of at least one aromatic dicarboxylic acid or a derivative thereof; The second component B is derived from a repeating unit consisting of 1,4-butanediol, The content of hydroxyl groups bonded to aliphatic dicarboxylic acids in the semi-aromatic polyester is 17 to 40 mmol / kg, the content of hydroxyl groups bonded to aromatic dicarboxylic acids in the semi-aromatic polyester is 17 to 40 mmol / kg, and the total hydroxyl group content is 35 to 80 mmol / kg.

[0010] In the polyester synthesis process, the molecular structure of the final polyester varies greatly due to the influence of many factors, such as differences in the structure or ratio of raw material monomers, differences in the types of catalysts, branching agents, and chain extenders, the production process, reaction time, and polymerization temperature. Research in this invention has revealed that the hydroxyl group content in semi-aromatic polyesters can affect their compatibility with materials such as polylactic acid. If the hydroxyl group content is too high or too low, the compatibility of semi-aromatic polyesters with materials such as polylactic acid will be poor.

[0011] In the present invention, it has been unexpectedly found that by controlling the hydroxyl group content in the semi-aromatic polyester, in particular by controlling the content of hydroxyl groups bound to aliphatic dicarboxylic acids in the semi-aromatic polyester to 17-40 mmol / kg, controlling the content of hydroxyl groups bound to aromatic dicarboxylic acids in the semi-aromatic polyester to 17-40 mmol / kg, and controlling the total hydroxyl group content to 35-80 mmol / kg, the compatibility of the semi-aromatic polyester with materials such as polylactic acid can be significantly improved, and thereby a film material with high strength and tear resistance can be obtained.

[0012] In the context of the present invention, component a1) an aliphatic dicarboxylic acid or derivative thereof is selected from one or more mixtures of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,11-undecanedicarboxylic acid, 1,10-decanedicarboxylic acid, undecanedioic acid, 1,12-dodecanedicarboxylic acid, hexadecanedioic acid, eicosanedioic acid or tetracosanedioic acid, or their ester derivatives or their anhydride derivatives.

[0013] Specific examples of component a1) include oxalic acid, dimethyl oxalate, malonic acid, dimethyl malonate, succinic acid, dimethyl succinate, methylsuccinic acid, glutaric acid, dimethyl glutarate, bis(2-hydroxyethyl) glutarate, bis(3-hydroxypropyl) glutarate, bis(4-hydroxybutyl) glutarate, 2-methylglutaric acid, 3-methylglutaric acid, adipic acid, dimethyl adipate, bis(2-hydroxyethyl) adipate, bis(3-hydroxypropyl) adipate, bis(4-hydroxybutyl) adipate, 3-methyladipic acid, 2,2,5,5-tetramethyladipic acid, pimelic acid, suberic acid, azelaic acid, dimethyl azelaate, sebacic acid, 1,11 The acidic acid is selected from one or more of succinic acid, adipic acid, sebacic acid, 1,12-dodecanedicarboxylic acid, 1,10-decanedicarboxylic acid, undecanedioic acid, 1,12-dodecanedicarboxylic acid, hexadecanedioic acid, eicosanedioic acid, tetracosanedioic acid, dimer acid, and their ester derivatives or anhydride derivatives, preferably one or more of succinic acid, adipic acid, sebacic acid, 1,12-dodecanedicarboxylic acid, and their ester derivatives or anhydride derivatives, more preferably one or two of adipic acid, sebacic acid, or their ester derivatives or anhydride derivatives, and most preferably adipic acid, or its ester derivatives or anhydride derivatives.

[0014] In the present invention, the aromatic dicarboxylic acid or its derivative, component a2), is selected from a mixture of one or more of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or their ester derivatives or their anhydride derivatives, and is preferably terephthalic acid, or its ester derivatives or its anhydride derivatives.

[0015] Specific examples of component a2) include terephthalic acid, dimethyl terephthalate, bis(2-hydroxyethyl) terephthalate, bis(3-hydroxypropyl) terephthalate, bis(4-hydroxybutyl) terephthalate, isophthalic acid, dimethyl isophthalate, bis(2-hydroxyethyl) isophthalate, bis(3-hydroxypropyl) isophthalate, bis(4-hydroxybutyl) isophthalate, 2,6-naphthalenedicarboxylic acid, dimethyl 2,6-phthalate, 2,7-naphthalenedicarboxylic acid, dimethyl 2,7-phthalate, 3,4'-diphenyl ether dicarboxylic acid, dimethyl 3,4'-diphenyl ether dicarboxylate, 4,4'-diphenyl ether dicarboxylate, dimethyl 4,4'-diphenyl ether dicarboxylate, 3,4'-phenylene sulfide dicarboxylic acid, dimethyl 3,4'-phenylene sulfide dicarboxylate, 4, The carboxylic acid may be selected from one or more of 4'-diphenylsulfidedicarboxylic acid, dimethyl 4,4'-phenylenesulfidedicarboxylate, 3,4'-diphenylsulfonedicarboxylic acid, dimethyl 3,4'-diphenylsulfonedicarboxylate, 4,4'-diphenylsulfonedicarboxylic acid, dimethyl 4,4'-diphenylsulfonedicarboxylate, 3,4'-benzophenonedicarboxylic acid, dimethyl 3,4'-benzophenonedicarboxylate, 4,4'-benzophenonedicarboxylic acid, dimethyl 4,4'-benzophenonedicarboxylate, 1,4-naphthalenedicarboxylic acid, dimethyl 1,4-naphthalenedicarboxylate, 4,4'-methylenebis(benzoic acid), 4,4'-methylenebis(dimethylbenzoate), or an ester derivative or an anhydride thereof, and is preferably terephthalic acid or an ester derivative or an anhydride derivative thereof. In the present invention, the semi-aromatic polyester also optionally contains a third component C, which is preferably a compound having at least three functional groups, and more preferably a compound having 3 to 6 functional groups, and is preferably selected from one or more of tartaric acid, citric acid, malic acid, trimethylolpropane, trimethylolethane, pentaerythritol, polyether triol, glycerin, 1,3,5-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid anhydride, 1,2,4,5-benzenetetracarboxylic acid, and pyromellitic dianhydride, and more preferably trimethylolpropane, pentaerythritol, or glycerin.

[0016] Based on the total molar amount of the first component A, the content of the third component C is 0.01 to 5.0 mol %, preferably 0.02 to 2.0 mol %.

[0017] The semi-aromatic polyester may further comprise a fourth component D which is a chain extender.

[0018] The chain extender is one or more mixtures of isocyanates, isocyanurates, peroxides, epoxides, oxazolines, oxazines, lactams, carbodiimides, or polycarbodiimides containing two or more functional groups.

[0019] The isocyanate containing two or more functional groups may be an aromatic or aliphatic isocyanate, preferably an aromatic or aliphatic diisocyanate. Preferably, the aromatic diisocyanate is toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, diphenylmethane 2,2'-diisocyanate, diphenylmethane 2,4'-diisocyanate, diphenylmethane 4,4'-diisocyanate, naphthalene 1,5-diisocyanate, or xylene diisocyanate.

[0020] More preferably, the aromatic diisocyanate is diphenylmethane 2,2'-diisocyanate, diphenylmethane 2,4'-diisocyanate, or diphenylmethane 4,4'-diisocyanate.

[0021] The isocyanate containing two or more functional groups may be tris(4-isocyanato-phenyl)methane, which has three rings.

[0022] Preferably, the aliphatic diisocyanate is any linear or branched alkylene diisocyanate or cycloalkylene diisocyanate containing 2 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The aliphatic diisocyanate may be hexamethylene 1,6-diisocyanate, isophorone diisocyanate, or methylenebis(4-isocyanatocyclohexane), most preferably hexamethylene 1,6-diisocyanate or isophorone diisocyanate.

[0023] Preferably, the isocyanurate having two or more functional groups is an aliphatic isocyanurate derived from an alkylene diisocyanate or cycloalkylene diisocyanate having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, such as isophorone diisocyanate or methylenebis(4-isocyanatocyclohexane). The alkylene diisocyanate may be a linear or branched compound. In particular, isocyanurates based on cyclic trimers, pentamers, or higher oligomers of n-hexamethylene diisocyanate, such as hexamethylene 1,6-diisocyanate, are preferred.

[0024] Preferably, the peroxide having two or more functional groups is preferably benzoyl peroxide, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(tert-butylperoxy)methylcyclododecane, n-butyl 4,4-di(butylperoxy)pentanoate, dicumyl peroxide, tert-butyl peroxybenzoate, dibutyl peroxide, α,α-di(tert-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hex-3-yne, or tert-butylcumene peroxide.

[0025] Preferably, the epoxide having two or more functional groups is selected from the group consisting of hydroquinone diglycidyl ether, resorcinol diglycidyl ether, 1,6-hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, diglycidyl terephthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, dimethyl diglycidyl phthalate, phenylene diglycidyl ether, ethylene diglycidyl ether, trimethylene diglycidyl ether, tetramethylene diglycidyl ether, hexamethylene diglycidyl ether, sorbitol diglycidyl ether, polyglycerin polyglycidyl ether, and the like. diglycidyl ether, pentaerythritol polyglycidyl ether, diglycerin polyglycidyl ether, glycerin polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether or poly 1,4-butylene glycol diglycidyl ether.

[0026] The epoxide having two or more functional groups is preferably a copolymer based on styrene, acrylic esters and / or methacrylic esters and containing epoxy groups, the epoxy groups being preferably glycidyl methacrylate. Compounds that have proven advantageous are copolymers in which the proportion of glycidyl methacrylate in the copolymer is greater than 20% by weight, more preferably greater than 30% by weight, and even more preferably greater than 50% by weight. The epoxy equivalent weight in these copolymers is preferably 150 to 3000 g / equivalent, more preferably 200 to 500 g / equivalent. The weight-average molecular weight Mw of the copolymer is preferably 2000 to 25000, more preferably 3000 to 8000. The number-average molecular weight Mn of the copolymer is preferably 400 to 6000, more preferably 1000 to 4000. The polydispersity index (Q=Mw / Mn) is preferably 1.5 to 5.

[0027] The oxazoline and oxazine having two or more functional groups are preferably dioxazoline or dioxazine, and the bridging moiety is a single bond, (CH2)z-alkylene (where z=2, 3, or 4), such as methylene, eth-1,2-diyl, propa-1,3-diyl, or propa-1,2-diyl, or phenylene. Specifically, the dioxazoline is 2,2'-bis(2-oxazoline), bis(2-oxazolinyl)methane, 1,2-bis(2-oxazolinyl)ethane, 1,3-bis(2-oxazolinyl)propane, or 1,4-bis(2-oxazolinyl)butane, 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(4,4'-dimethyl-2-oxazoline), 2,2'-bis(4-ethyl-2-oxazoline), 2,2'-bis(4,4'-diethyl-2-oxazoline), 2,2'-bis(4-propyl-2-oxazoline), 2,2'-bis(4-butyl-2-oxazoline), 2,2'-bis(4-hexyl-2-oxazoline), 2,2'-bis(4-phenyl-2-oxazoline), 2,2'-bis(4-cyclohexyl-2-oxazoline), 2,2'-bis( 4-phenylmethyl-2-oxazoline), 2,2'-p-phenylenebis(4-methyl-2-oxazoline), 2,2'-p-phenylenebis(4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis(4-methyl-2-oxazoline), 2,2'-m-phenylenebis(4,4'-dimethyl-2-oxazoline), 2,2'-hexamethylenebis(2-oxazoline), 2,2'-octamethyl 2,2'-tetramethylenebis(4,4'-dimethyl-2-oxazoline), 2,2'-9,9'-diphenoxyethanebis(2-oxazoline), 2,2'-cyclohexylenebis(2-oxazoline), or 2,2'-diphenylene(2-oxazoline).

[0028] More preferred is 1,4-bis(2-oxazolinyl)benzene, 1,2-bis(2-oxazolinyl)benzene, or 1,3-bis(2-oxazolinyl)benzene. Specifically, the dioxazine is 2,2'-bis(2-dioxazine), bis(2-dioxazinyl)methane, 1,2-bis(2-dioxazinyl)ethane, 1,3-bis(2-dioxazinyl)propane, 1,4-bis(2-dioxazinyl)butane, 1,4-bis(2-dioxazinyl)benzene, 1,2-bis(2-dioxazinyl)benzene, or 1,3-bis(2-dioxazinyl)benzene.

[0029] The carbodiimide or polycarbodiimide having two or more functional groups is preferably N,N'-di-2,6-diisopropylphenylcarbodiimide, N,N'-di-o-tolylcarbodiimide, N,N'-diphenylcarbodiimide, N,N'-dioctyldecylcarbodiimide, N,N'-di-2,6-dimethylphenylcarbodiimide, N-tolyl-N'-cyclohexylcarbodiimide, N,N'-di-2,6-di-tert-butylphenylcarbodiimide, N-tolyl-N'-phenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N,N'-di-p-aminophenylcarbodiimide, N,N'-di-p-hydroxyphenylcarbodiimide, N,N'-dicyclohexylcarbodiimide, N,N'-di-p-tolylcarbodiimide, p-phenylenebisdi-o-tolylcarbodiimide, p-phenylenebisdicyclohexylcarbodiimide, hexamethylenebisdicyclohexylcarbodiimide, 4,4'-dicyclohexylmethanecarbodiimide, ethylenebisdiphenylcarbodiimide, N,N'- Benzyl carbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N-octadecyl-N'-tolylcarbodiimide, N-cyclohexyl-N'-tolylcarbodiimide, N-phenyl-N'-tolylcarbodiimide, N-benzyl-N'-tolylcarbodiimide, N,N'-di-o-ethylphenylcarbodiimide, N,N'-di-p-ethylphenylcarbodiimide, N,N'-di-o-isopropylphenylcarbodiimide, N,N'-di-p-isopropyl N,N'-di-o-isobutylphenylcarbodiimide, N,N'-di-p-isobutylphenylcarbodiimide, N,N'-di-2,6-diethylphenylcarbodiimide, N,N'-di-2-ethyl-6-isopropylphenylcarbodiimide, N,N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, N,N'-di-2,4,6-trimethylphenylcarbodiimide, N,N'-di-2,4,6-triisopropylphenylcarbodiimide, N,N'-di-2,4,6-triisobutylphenylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, tert-butylisopropylcarbodiimide, di-β-naphthylcarbodiimide or di-tert-butylcarbodiimide.

[0030] Preferably, the content of the fourth component D is 0.01 to 5 mol % based on the total molar amount of the first component A.

[0031] Preferably, the viscosity number of the semi-aromatic polyester is 150-350 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0032] Preferably, the carboxyl group content of the semi-aromatic polyester is 5 to 50 mmol / kg, more preferably 10 to 30 mmol / kg.

[0033] The present invention also provides a method for preparing the above semi-aromatic polyester, which comprises the steps of: a step S1 of adding a1 in the first component A and the second component B to a slurry blending kettle in accordance with the ratio, transporting the blended slurry to a first esterification reactor, adding the refluxed second component B and the catalyst to the first esterification reactor through a separate route, and conducting an esterification reaction at 150 to 200°C and 30 to 110 kPa for 2 to 4 hours to obtain an esterification product Ba1; and adding a2 in the first component A and the second component B to a slurry blending kettle in accordance with the ratio, transporting the blended slurry to a second esterification reactor, adding the refluxed second component B and the catalyst to the second esterification reactor through a separate route, and conducting an esterification reaction at 200 to 250°C and 30 to 110 kPa for 2 to 4 hours to obtain an esterification product Ba2; Step S2, in which the esterification product Ba1 of step S1 is subjected to a primary polycondensation reaction at a reaction temperature of 170-220°C and a pressure of 1-10 kPa, and the esterification product Ba2 of step S1 is subjected to a primary polycondensation reaction at a reaction temperature of 230-270°C and a pressure of 1-10 kPa, and the two reaction products are subjected to a primary polycondensation reaction independently until each reaction product reaches a viscosity number of 15-60 ml / g as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to the GB / T 17931-1999 standard, thereby obtaining primary polycondensation products Pre-Ba1 and Pre-Ba2, respectively; Step S3: transferring the primary polycondensation reaction product Pre-Ba1 obtained in step S2 to a first final polymerization vessel at a reaction temperature of 180-230°C and a pressure of 10-500 Pa, and transferring the primary polycondensation reaction product Pre-Ba2 obtained in step S2 to a second final polymerization vessel at a reaction temperature of 220-270°C and a pressure of 10-500 Pa, and independently polycondensing the two reaction products until the reaction products reach a viscosity of 50-180 ml / g as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard, thereby obtaining final polymerization products Poly-Ba1 and Poly-Ba2, respectively; and step S4, in which the final polymerization products Poly-Ba1 and Poly-Ba2 obtained in step S3 are mixed and reacted in a mixer to obtain a semi-aromatic polyester having a viscosity of 150 to 300 ml / g as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0034] All pressures mentioned in the process of this invention are absolute pressures (absolute pressure).

[0035] Preferably, in step S1, a catalyst is added in an amount of 0.001 to 1% by weight of the final semi-aromatic polyester when preparing the Ba2 esterification product. Preferably, the catalyst addition amount is 0.02 to 0.2% by weight of the final semi-aromatic polyester. Controlling the catalyst addition amount can improve the stability of subsequent processing. Furthermore, the catalyst may be a tin compound, antimony compound, cobalt compound, lead compound, zinc compound, aluminum compound, or titanium compound, more preferably a zinc compound, aluminum compound, or titanium compound, and most preferably a titanium compound. The advantage of titanium compounds, such as tetrabutyl orthotitanate or tetraisopropyl orthotitanate, over other compounds is that the residual toxicity remaining in the product or downstream products is low. This characteristic is particularly important for biodegradable polyesters, as they enter the environment directly in the form of compost bags or coated films.

[0036] In S1, the total molar amount of the second component B is usually 1.1 to 3.0 times that of the first component A, and excess second component B is recovered through a purification device (usually a distillation column) connected to the esterification reactor and then fed to the esterification reactor. The amount of recovered second component B is usually 20 to 50% by weight of the amount of fresh second component B.

[0037] In S2, when preparing the Pre-Ba1 prepolymer, the reaction temperature is more preferably 180 to 200° C., and the reaction pressure is more preferably 2 to 5 kPa.

[0038] In step S2, when preparing the Pre-Ba2 prepolymer, the remaining catalyst from step S1 can be added in step S2, if necessary. The reaction temperature is more preferably 240 to 260°C, and the reaction pressure is more preferably 2 to 5 kPa.

[0039] The typical reaction time for preparing Pre-Ba1 and Pre-Ba2 in S2 is 2-5 hours. Under normal circumstances, this reaction time results in primary polycondensation products Pre-Ba1 and Pre-Ba2 with viscosities of 15-60 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999. The carboxyl group content of the primary polycondensation products Pre-Ba1 and Pre-Ba2 after the S2 reaction is typically 10-60 mmol / kg.

[0040] In the polycondensation reaction step S3, a passivator can be mixed with the prepolyester, if necessary. Usable passivators are typically phosphorus compounds, including phosphoric acid, phosphorous acid, and their esters. The amount of passivator is typically 0.001 to 0.1% by weight, preferably 0.01 to 0.05% by weight, based on the weight of the final polyester.

[0041] In S3, when preparing Poly-Ba1 polyester, the reaction temperature is more preferably 190 to 220°C, and the reaction pressure is more preferably 50 to 200Pa.

[0042] In S3, when preparing Poly-Ba2 polyester, the reaction temperature is more preferably 240 to 260°C, and the reaction pressure is more preferably 20 to 100Pa.

[0043] In S3, the polycondensation reaction time is preferably 1 to 5 hours, more preferably 2 to 4 hours. The resulting Poly-Ba1 and Poly-Ba1 polyester have a viscosity of 50 to 180 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C, according to GB / T 17931-1999. Furthermore, the carboxyl group content of the Poly-Ba1 and Poly-Ba1 polyester after the S3 reaction is typically 5 to 60 mmol / kg, more preferably 10 to 30 mmol / kg.

[0044] In step S4, Poly-Ba1 and Poly-Ba2 are mixed in a mixer, which includes a feed system, a temperature control system, a high-shear homogenizing pump, and a homogenizer. The mixer temperature range is 200°C to 280°C, preferably 240°C to 260°C, and the residence time of Poly-Ba1 and Poly-Ba2 in the mixer is 1 to 4 hours, preferably 1.5 to 2 hours. After passing through the mixer, the resulting reaction product reaches a viscosity of 150 to 300 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0045] Preferably, the preparation method optionally further includes step S5, in which the semi-aromatic polyester obtained in step S4 is added to a fourth component D to carry out a chain extension reaction at a reaction temperature of 200 to 270°C, with a reaction residence time of 0.5 to 15 minutes, preferably 2 to 5 minutes. The reaction is completed when the reaction product reaches a viscosity number of 150 to 350 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0046] The present invention also provides the application of the above semi-aromatic polyester in the manufacture of compostable and degradable products, which can be fibers, films or containers, etc.

[0047] The present invention also provides a semi-aromatic polyester molding composition, which comprises, in weight percentages: 5 to 95% by weight of the semi-aromatic polyester; 5 to 95 wt. % of additives and / or other polymers; and 0 to 70% by weight of reinforcing materials and / or fillers.

[0048] As a particular option, the additive and / or other polymer may be at least one or more components selected from aliphatic polyesters, polycaprolactone, starch, cellulose, polyhydroxyalkanoates, and polylactic acid.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] The present invention provides a semi-aromatic polyester, and by controlling the hydroxyl group content in the semi-aromatic polyester, particularly by controlling the content of hydroxyl groups bound to aliphatic dicarboxylic acids in the semi-aromatic polyester to 17-40 mmol / kg, controlling the content of hydroxyl groups bound to aromatic dicarboxylic acids in the semi-aromatic polyester to 17-40 mmol / kg, and controlling the total hydroxyl group content to 35-80 mmol / kg, the compatibility of the semi-aromatic polyester with materials such as polylactic acid can be significantly improved, thereby producing a film material with high strength and tear resistance. [Brief explanation of the drawings]

[0051] [Figure 1] 1H NMR of PBAT obtained by the reaction of terephthalic acid, adipic acid, and 1,4-butanediol, measured using a Bruker AV 500 nuclear magnetic resonance spectrometer. [Figure 2] These peaks correspond to the CH2 of the hydroxyl group bonded to adipic acid and the hydroxyl group bonded to terephthalic acid in PBAT. DETAILED DESCRIPTION OF THE INVENTION

[0052] Unless otherwise specified, the raw materials, reagents, and solvents used in the present invention were purchased commercially without any treatment. The present invention will be described in more detail below in conjunction with examples. However, the embodiments of the present invention are not limited to the following examples. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered equivalent substitutions and are all included within the scope of protection of the present invention. In this specification, "parts" and "%" mean "parts by mass" and "% by mass," respectively, unless otherwise specified.

[0053] Performance test method: Test for hydroxyl group content in semi-aromatic polyester (using polybutylene adipate terephthalate (PBAT) obtained in Example 1 as an example): 20 mg of the semi-aromatic polyester sample was dissolved in 0.6 ml of deuterated chloroform, and 1 H NMR was measured at room temperature using a Bruker AV 500 nuclear magnetic resonance spectrometer, with the peak of the chloroform solvent being standardized at 7.26 ppm.

[0054] According to the literature (Chen, X.; Chen, W.; Zhu, G.; Huang, F.; Zhang, J., Synthesis, 1H-NMR characterization, and biodegradation behavior of aliphatic-aromatic random copolyester. J. Appl. Polym. Sci. 2007, 104(4):2643-2649), the four hydrogen atoms of the benzene ring in the terephthalic acid repeat unit appear at around 8.10 ppm, while the four hydrogen atoms of the two CH2 units adjacent to the carbonyl group in the adipic acid repeat unit appear at around 2.33 ppm. This is shown in Figure 1. Thus, the molar content of the diacid component can be expressed as the integrated area (IT and IA) of the two peaks at 8.10 ppm and 2.33 ppm. Molar content of terephthalic acid in PBAT = IT / (IT+IA) × 100% Adipic acid molar content in PBAT = IA / (IT+IA) × 100%

[0055] According to the literature (Herrera, R.; Franco, L.; Rodriguez-Galan, A.; Puiggalli, J., Characterization and degradation behavior of poly(butylene adipate-co-terephthalate)sJ Polym. Sci., Part A: Polym. Chem. 2002, 40(23):4141-4157), the CH2 adjacent to the hydroxyl group bonded to adipic acid appears at around 3.68 ppm, and the CH2 adjacent to the hydroxyl group bonded to terephthalic acid appears at around 3.74 ppm.

[0056] From Figure 2, the following can be calculated:

[0057] The content XA (unit: mmol / kg) of hydroxyl groups bonded to aliphatic dicarboxylic acid (adipic acid) in the semi-aromatic polyester PBAT is as follows:

number

number

[0058] Viscosity number of semi-aromatic polyester: According to the GB / T 17931-1999 standard, the sample concentration was 5 mg / ml measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C.

[0059] Carboxyl group content: First, the acid number (AN) (mg KOH / g) was determined according to DIN EN 12634 of October 1998, and then the carboxyl group content (mmol / kg) was determined as (AN / 56) × 103. The solvent mixture used contained 1 volume part DMSO, 8 volume parts isopropyl alcohol, and 7 volume parts toluene, with a solvent volume of 100 ml. 3–6 g of semi-aromatic polyester was taken and heated to 70 °C to dissolve all the polymer into a clear solution. The solution temperature was maintained between 60–70 °C to avoid polymer precipitation during the titration process. To avoid the use of highly toxic tetramethylammonium hydroxide, tetrabutylammonium hydroxide was used as the titrant. At the same time, to prevent the mixed solvent from absorbing CO2 from the air and affecting the amount of titrant consumed by the blank solvent, when testing the amount of titrant consumed by the blank solvent, the blank solvent was heated to 70°C and kept at a constant temperature for 0.5 hours. To prevent the blank solvent from further absorbing CO2 from the air after heating, the blank solvent was immediately titrated with alkaline solution.

[0060] Tear strength: The obtained polyester composition was blown into a film with a double air ring type film blowing machine to a film thickness of 20 μm, and the air volumes of the inner air ring and the outer air ring were controlled between 1:1 and 1:3, with a blow-up ratio of 2.5 to 4.0.

[0061] According to GB / T 1040.3-2006, Part 3 of the Test for Tensile Properties of Plastics: Test Conditions for Films and Sheets, the transverse tensile strength and longitudinal tensile strength were measured, respectively.

[0062] According to GB / T 16578.2-2009, Part 2 of the Tear Resistance Determination for Plastic Films and Sheets: Elmendorf Method, the transverse tear strength and longitudinal tear strength were measured, respectively.

[0063] Example 1: S1. 355 kg / h of adipic acid and 328 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 109 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0064] 355 kg / h of terephthalic acid and 289 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 96 kg / h, and simultaneously 0.43 kg / h of glycerin and 0.331 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0065] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 4 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 45 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0066] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 35 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0067] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 120 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 146 ml / g in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0068] The prepolymer Pre-Ba2 was fed via a melt pump to a second final polymerization vessel, where the temperature was 250°C, the pressure was 20 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 135 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0069] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer, the temperature of which was 250°C, and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, and simultaneously 4.2 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set to 250°C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0070] Example 2: S1. 491 kg / h of sebacic acid and 328 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 109 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. The water, tetrahydrofuran, and butanediol produced by the reaction were removed, yielding an esterification product Ba1.

[0071] 355 kg / h of terephthalic acid and 289 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 96 kg / h, and simultaneously 0.43 kg / h of glycerin and 0.331 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0072] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 4 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 46 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0073] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 37 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0074] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 120 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 151 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0075] The prepolymer Pre-Ba2 was fed via a melt pump to the second final polymerization reactor, where the temperature was 250°C, the pressure was 20 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 132 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0076] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer, the temperature of which was 250°C, and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, and simultaneously 4.2 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set to 250°C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0077] Example 3: S1. 355 kg / h of adipic acid and 328 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 109 kg / h, and simultaneously 0.179 kg / h of n-butyl titanate was added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. The water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0078] 355 kg / h of terephthalic acid and 289 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 96 kg / h, and simultaneously 0.331 kg / h of n-butyl titanate was added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. The water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0079] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 4 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 33 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0080] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 27 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0081] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 120 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 134 ml / g in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0082] The prepolymer Pre-Ba2 was fed via a melt pump to a second final polymerization vessel, where the temperature was 250°C, the pressure was 20 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 128 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0083] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer, the temperature of which was 250°C, and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, and simultaneously 4.2 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set to 250°C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0084] Example 4: S1. 355 kg / h of adipic acid and 328 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 109 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0085] 500 kg / h of terephthalic acid and 407 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 136 kg / h, and simultaneously 0.61 kg / h of glycerin and 0.466 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0086] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 4 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 44 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0087] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.200 kg / h of n-butyl titanate and 0.501 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 29 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0088] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 120 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 142 ml / g in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0089] The prepolymer Pre-Ba2 was fed via a melt pump to the second final polymerization vessel, where the temperature was 250°C, the pressure was 20 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 133 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0090] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer, the temperature of which was 250°C, and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, and simultaneously 5.03 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set to 250°C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0091] Example 5: S1. 355 kg / h of adipic acid and 328 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 109 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0092] 355 kg / h of terephthalic acid and 289 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 96 kg / h, and simultaneously 0.43 kg / h of glycerin and 0.331 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0093] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 8 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 31 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0094] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 8 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 21 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0095] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 300 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 116 ml / g in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0096] The prepolymer Pre-Ba2 was fed via a melt pump to a second final polymerization vessel, where the temperature was 250°C, the pressure was 200 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 105 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0097] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer, the temperature of which was 250°C, and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, and simultaneously 4.2 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set to 250°C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0098] Example 6: S1. 355 kg / h of adipic acid and 219 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 66 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0099] 355 kg / h of terephthalic acid and 193 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 58 kg / h, and simultaneously 0.43 kg / h of glycerin and 0.331 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0100] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 4 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 28 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0101] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 21 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0102] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 120 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 96 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0103] The prepolymer Pre-Ba2 was fed via a melt pump to the second final polymerization vessel, where the temperature was 250°C, the pressure was 20 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 83 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0104] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer, the temperature of which was 250°C, and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, and simultaneously 4.2 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set to 250°C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0105] Example 7: S1. 355 kg / h of adipic acid and 328 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 109 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0106] 355 kg / h of terephthalic acid and 289 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 96 kg / h, and simultaneously 0.43 kg / h of glycerin and 0.331 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0107] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 4 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 43 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0108] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 37 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0109] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 120 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 136 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0110] The prepolymer Pre-Ba2 was fed via a melt pump to the second final polymerization vessel, where the temperature was 250°C, the pressure was 20 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 129 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0111] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer at a temperature of 250°C and a residence time of 2 hours. The resulting polyester was then introduced into a twin-screw extruder, pelletized using an underwater pelletizer, and dried to obtain the final polyester product.

[0112] Example 8: S1. 355 kg / h of adipic acid and 328 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 109 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0113] 355 kg / h of terephthalic acid and 289 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 96 kg / h, and simultaneously 0.43 kg / h of glycerin and 0.331 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0114] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was set to 200°C, the reactor pressure was set to 2 kPa, and the residence time was set to 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 51 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0115] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 1 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 43 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0116] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 80 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 163 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0117] The prepolymer Pre-Ba2 was fed via a melt pump to the second final polymerization vessel, where the temperature was 250°C, the pressure was 10 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 147 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0118] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer, the temperature of which was 250°C, and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, and simultaneously 4.2 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set to 250°C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0119] Example 9: S1. 355 kg / h of adipic acid and 328 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 109 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0120] 355 kg / h of terephthalic acid and 289 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 96 kg / h, and simultaneously 0.43 kg / h of glycerin and 0.331 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0121] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 4 kPa, and the residence time was 2-2.5 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 29 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0122] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 2 to 2.5 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 18 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0123] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 120 Pa, and the reaction time was 2-3 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 106 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0124] The prepolymer Pre-Ba2 was fed via a melt pump to a second final polymerization vessel, where the temperature was 250°C, the pressure was 20 Pa, and the reaction time was 2-3 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 95 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0125] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer, the temperature of which was 250°C, and the residence time was 1 hour. The resulting polyester was then introduced into a twin-screw extruder, and simultaneously 4.2 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set to 250°C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0126] Comparative Example 1: S1. 355 kg / h of terephthalic acid, 355 kg / h of adipic acid, 617 kg / h of 1,4-butanediol, 0.92 kg / h of glycerin, and 0.51 kg / h of tetrabutyl orthotitanate were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to an esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process column was set to 206 kg / h, and the reactor pressure was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, yielding an esterification product BA.

[0127] S2. The esterification product BA was gravity-fed into the pre-polycondensation reactor, and simultaneously 0.22 kg / h of n-butyl titanate and 0.55 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-BA reached a viscosity of 35 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0128] S3. The prepolymer Pre-BA was fed via a melt pump into the disk reactor (i.e., the final polymerization reactor), and the temperature of the final polymerization reactor was set to 250°C, the pressure to 20 Pa, and the reaction time to 3-4 hours. At this point, the reaction product Poly-BA reached a viscosity of 133 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0129] S4. The obtained polyester was introduced into a twin-screw extruder, and simultaneously 4.2 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set at 250° C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0130] Comparative Example 2: S1. 355 kg / h of adipic acid and 153 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 66 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0131] 355 kg / h of terephthalic acid and 135 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 58 kg / h, and simultaneously 0.43 kg / h of glycerin and 0.331 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 4 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0132] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 4 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 15 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0133] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 10 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0134] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 120 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity of 83 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0135] The prepolymer Pre-Ba2 was fed via a melt pump to the second final polymerization vessel, where the temperature was 250°C, the pressure was 20 Pa, and the reaction time was 3-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity of 62 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0136] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer, the temperature of which was 250°C, and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, and simultaneously 4.2 kg / h of hexamethylene diisocyanate (HDI) was metered in, and the temperature was set to 250°C. After a residence time of 3 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0137] Comparative Example 3: S1. 355 kg / h of adipic acid and 328 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a first esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 109 kg / h, and simultaneously 0.49 kg / h of glycerin and 0.179 kg / h of n-butyl titanate were added. The pressure in the reactor was controlled to 40 kPa (absolute pressure), the temperature to 190°C, and the residence time to 2 to 3 hours. The water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba1 was obtained.

[0138] 355 kg / h of terephthalic acid and 289 kg / h of 1,4-butanediol were continuously added to a slurry preparation vessel, and the prepared slurry was continuously supplied to a second esterification reactor. The flow rate of 1,4-butanediol via a separate route from the bottom of the process tower was set to 96 kg / h, and simultaneously 0.43 kg / h of glycerin and 0.331 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 240°C, and the residence time to 2 to 3 hours. Water, tetrahydrofuran, and butanediol produced by the reaction were removed, and an esterification product Ba2 was obtained.

[0139] S2. The esterification product Ba1 was transferred to the first preliminary polycondensation reactor, and simultaneously 0.077 kg / h of n-butyl titanate and 0.198 kg / h of triphenyl phosphate were added. The temperature was 200°C, the reactor pressure was 4 kPa, and the residence time was 1-2 hours to extract excess butanediol. At this point, the reaction product Pre-Ba1 reached a viscosity of 25 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0140] The esterification product Ba2 was transferred to a second pre-polycondensation reactor, and simultaneously 0.142 kg / h of n-butyl titanate and 0.356 kg / h of triphenyl phosphate were added. The temperature was 250°C, the reactor pressure was 2 kPa, and the residence time was 1 to 2 hours to extract excess butanediol. At this point, the reaction product Pre-Ba2 reached a viscosity of 13 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0141] S3. The prepolymer Pre-Ba1 was fed via a melt pump into the first final polymerization vessel. The temperature of the first final polymerization vessel was 220°C, the pressure was 120 Pa, and the reaction time was 30-60 minutes. At this point, the reaction product Pre-Ba1 reached a viscosity of 95 ml / g, measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0142] The prepolymer Pre-Ba2 was fed via a melt pump to a second final polymerization vessel, where the temperature was 250°C, the pressure was 20 Pa, and the reaction time was 30-60 minutes. At this point, the reaction product Pre-Ba2 reached a viscosity of 76 ml / g, as measured in a 1:1 weight ratio phenol / o-dichlorobenzene solution in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

[0143] S4. The two final polymerization products, Poly-Ba1 and Poly-Ba2, were continuously fed into a mixer at a temperature of 250°C with a residence time of 30 to 60 minutes. The resulting polyester was then introduced into a twin-screw extruder, and 4.2 kg / h of hexamethylene diisocyanate (HDI) was simultaneously metered in and the temperature was set to 250°C. After a residence time of 2 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product. [Table 1]

[0144] As can be seen from the above results, in Comparative Example 1, a mixed esterification step was used in the entire process, and the polymerization temperature was relatively high, so the part derived from the aliphatic polyester in the semi-aromatic polyester was prone to thermal degradation, and side reactions were relatively frequent, resulting in the production of carboxyl groups and some other non-hydroxyl carboxyl group terminals (such as double bonds), and the hydroxyl group content in the obtained semi-aromatic polyester was relatively low.

[0145] In Comparative Example 2, the alcohol to acid ratio was only 1.0, so the viscosity number of the prepolymerization and polycondensation product was very low, making chain extension difficult, and the resulting semi-aromatic polyester had very few hydroxyl groups and very many carboxyl groups, resulting in a low viscosity number.

[0146] In Comparative Example 3, the reaction time of the polymerization step was short, so the hydroxyl group content in the semi-aromatic polyester was high, the viscosity number was low, and the reaction time was short, so the thermal degradation was small, and the carboxyl group content was low.

[0147] Examples 10 to 18 and Comparative Examples 4 to 6: In the following parts by weight: Semi-aromatic polyester: 67 PLA:10 Calcium carbonate: 22 Epoxy copolymer: 0.5 Erucic acid amide: 0.2 The above raw materials were mixed and charged into a twin-screw extruder, extruded at 170 to 210°C, and granulated to obtain a semi-aromatic polyester composition.

[0148] PLA was purchased from Natureworks, Inc. in the United States, with the product number 4060D. Calcium carbonate was purchased from Jiangsu Yifeng Powder Raw Materials Co., Ltd., with the product number YF-2350. Epoxy copolymer was purchased from BASF, with the product number Joncryl® ADR 4370. Erucamide was purchased from Jiangxi Weike Petrochemical Co., Ltd., with the product number WK1890. [Table 2]

[0149] As can be seen from the above results, in Examples 10 to 18, PBAT resins with appropriate hydroxyl groups were used, and the resulting semi-aromatic polyester compositions had tensile strengths of 300 MPa or more and tear strengths of 1000 mN or more, all of which met the requirements for use. In Comparative Examples 4 and 5, the hydroxyl group content of the PBAT resin used was low, resulting in poor compatibility between PBAT and PLA, and the tensile strength and tear strength of the resulting semi-aromatic polyester compositions were significantly reduced. In Comparative Example 6, the hydroxyl group content of the PBAT resin used was too high, resulting in very low tensile strength and tear strength of the resulting semi-aromatic polyester composition.

Claims

1. A process S1 in which a1 in first component A and second component B are added to a slurry blending vessel in accordance with a ratio, the blended slurry is transported to a first esterification reactor, refluxed second component B and the catalyst are added to the first esterification reactor via a separate route, and an esterification reaction is carried out at 150-200°C and 30-110 kPa for 2-4 hours to obtain an esterification product Ba1, and a2 in first component A and second component B are added to a slurry blending vessel in accordance with a ratio, the blended slurry is transported to a second esterification reactor, refluxed second component B and the catalyst are added to the second esterification reactor via a separate route, and an esterification reaction is carried out at 200-250°C and 30-110 kPa for 2-4 hours to obtain an esterification product Ba2; a step S2 of carrying out a primary polycondensation reaction on the esterification product Ba1 of step S1 at a reaction temperature of 170 to 220°C and a pressure of 1 to 10 kPa, and then carrying out a primary polycondensation reaction on the esterification product Ba2 of step S1 at a reaction temperature of 230 to 270°C and a pressure of 1 to 10 kPa, and independently carrying out a primary polycondensation reaction on both the esterification product Ba1 and the esterification product Ba2 until each reaction product reaches a viscosity number of 15 to 60 ml / g as measured in a phenol / o-dichlorobenzene solution at a weight ratio of 1:1 in accordance with GB / T 17931-1999 standard in a constant temperature water bath at 25±0.05°C, thereby obtaining primary polycondensation reaction products Pre-Ba1 and Pre-Ba2, respectively; a step S3 of transferring the product Pre-Ba1 of the primary polycondensation reaction obtained in step S2 to a first final polymerization vessel having a reaction temperature of 180 to 230°C and a pressure of 10 to 500 Pa, and transferring the product Pre-Ba2 of the primary polycondensation reaction obtained in step S2 to a second final polymerization vessel having a reaction temperature of 220 to 270°C and a pressure of 10 to 500 Pa, and independently carrying out polycondensation reactions on both products until the reaction products reach a viscosity number of 50 to 180 ml / g as measured in a phenol / o-dichlorobenzene solution at a weight ratio of 1:1 in accordance with GB / T 17931-1999 standard in a constant temperature water bath at 25±0.05°C, thereby obtaining final polymerization products Poly-Ba1 and Poly-Ba2, respectively; and step S4 of mixing and reacting the final polymerization products Poly-Ba1 and Poly-Ba2 obtained in step S3 in a mixer to obtain a semi-aromatic polyester having a viscosity of 150 to 300 ml / g measured in a phenol / o-dichlorobenzene solution at a weight ratio of 1:1 in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard; Based on the total molar amount of the first component A, a1) 40 to 60 mol % of at least one aliphatic dicarboxylic acid or a derivative thereof, a2) a first component A comprising 40 to 60 mol % of at least one aromatic dicarboxylic acid or a derivative thereof; A second component B is a semi-aromatic polyester derived from repeating units consisting of 1,4-butanediol, A method for preparing a semi-aromatic polyester, characterized in that the content of hydroxyl groups bonded to aliphatic dicarboxylic acids in the semi-aromatic polyester is 17 to 40 mmol / kg, the content of hydroxyl groups bonded to aromatic dicarboxylic acids in the semi-aromatic polyester is 17 to 40 mmol / kg, and the total content of hydroxyl groups is 35 to 80 mmol / kg.

2. 2. The method for preparing a semi-aromatic polyester according to claim 1, wherein component a1) is selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,11-undecanedicarboxylic acid, 1,10-decanedicarboxylic acid, undecanedioic acid, 1,12-dodecanedicarboxylic acid, hexadecanedioic acid, eicosanedioic acid or tetracosanedioic acid, or ester derivatives thereof or anhydride derivatives thereof, or a mixture of one or more thereof.

3. A method for preparing a semi-aromatic polyester as described in claim 2, characterized in that component a1) is one or two of adipic acid, sebacic acid, or their ester derivatives or their anhydride derivatives.

4. 2. The method for preparing a semi-aromatic polyester according to claim 1, wherein component a2) is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or a mixture of one or more of their ester derivatives or anhydride derivatives.

5. A method for preparing a semi-aromatic polyester as described in claim 4, characterized in that component a2) is terephthalic acid or its ester derivative or its anhydride derivative.

6. Based on the total molar amount of the first component A, the semi-aromatic polyester also contains 0.01 to 5.0 mol % of a third component C and 0.01 to 5.0 mol % of a fourth component D; the third component C is selected from one or more of tartaric acid, citric acid, malic acid, trimethylolpropane, trimethylolethane, pentaerythritol, polyether triol, glycerin, 1,3,5-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid anhydride, 1,2,4,5-benzenetetracarboxylic acid, and pyromellitic dianhydride; 2. The method for preparing a semi-aromatic polyester according to claim 1, wherein the fourth component D is selected from one or more of isocyanates, isocyanurates, peroxides, epoxides, oxazolines, oxazines, lactams, carbodiimides or polycarbodiimides containing two or more functional groups.

7. The semi-aromatic polyester according to claim 6, wherein the third component C is trimethylolpropane, pentaerythritol, or glycerin.

8. 2. The method for preparing a semi-aromatic polyester according to claim 1, wherein the viscosity number of the semi-aromatic polyester is 150-350 ml / g, as measured in a phenol / o-dichlorobenzene solution at a weight ratio of 1:1 in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

9. 2. The method for preparing a semi-aromatic polyester according to claim 1, wherein the carboxyl group content of the semi-aromatic polyester is 5 to 50 mmol / kg.

10. The method for preparing an aromatic polyester according to claim 9, wherein the carboxyl group content of the semi-aromatic polyester is 10 to 30 mmol / kg.

11. 2. The method for preparing a semi-aromatic polyester according to claim 1, further comprising: S5, in which the semi-aromatic polyester obtained in step S4 is added to a fourth component D to carry out a chain extension reaction at a reaction temperature of 200 to 270°C, the reaction residence time is 0.5 to 15 minutes, preferably 2 to 5 minutes, and the reaction is completed when the reaction product reaches a viscosity number of 150 to 350 ml / g, as measured in a phenol / o-dichlorobenzene solution in a weight ratio of 1:1 in a constant temperature water bath at 25±0.05°C according to GB / T 17931-1999 standard.

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