Semi-aromatic polyester and its preparation method and application

Abstract

The present invention discloses a semi-aromatic polyester and its preparation method and application, which has a specific range of double bond content and has better melt heat residence stability and good color compared with known semi-aromatic polyesters.

Description

[Technical field]

[0001] The present invention relates to the field of biodegradable polyesters, in particular to semi-aromatic polyesters with specific double bond contents and their preparation methods and applications. [Background technology]

[0002] Biodegradable aliphatic-aromatic copolyesters can be prepared from aliphatic diacids or their derivatives, aliphatic diols, and aromatic diacids or their derivatives. This copolyester is represented by Ecoflex manufactured by BASF in Germany, whose raw materials are 1,6-adipic acid (AA), 1,4-butanediol (BDO), and terephthalic acid. This copolyester has excellent processing properties due to its low melt volume flow rate (MVR), and good hydrolysis resistance due to its very low acid value. However, compared with aromatic polyesters such as PET and PBT, semi-aromatic polyesters are prone to thermal decomposition, and structures such as double bonds and carboxyl groups are generated after thermal degradation, which reduces the performance of the polymerization product and is unfavorable for subsequent use. Summary of the Invention

[0003] In order to solve the above problems, the present invention aims to provide a semi-aromatic polyester, which has a specific double bond content, and therefore has better melt heat retention stability and good color.

[0004] Another object of the present invention is to provide a process for preparing said semi-aromatic polyester.

[0005] The above objectives of the present invention are achieved by the following technical solutions.

[0006] 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; A second component B is derived from a repeating unit consisting of a diol having 2 to 12 carbon atoms, The double bond content in the semi-aromatic polyester is 0.55 to 4.5 mmol / kg, preferably 0.70 to 2.5 mmol / kg, and more preferably 0.75 to 0.95 mmol / kg.

[0007] In the synthesis process of polyester, due to the influence of many factors such as the structure or ratio of raw material monomers, the type of catalyst, branching agent and chain extender, the production process, reaction time, polymerization temperature, etc., the molecular structure of the final polyester will have a large difference. In the present invention, research has found that the double bond content in semi-aromatic polyester is closely related to the melt heat retention stability and color of semi-aromatic polyester.

[0008] In the present invention, it has been unexpectedly found through research that by controlling the double bond content in the semi-aromatic polyester within the range of 0.55 to 4.5 mmol / kg, the resulting semi-aromatic polyester has better melt heat retention stability and good color.

[0009] In the context of the present invention, component a1) an aliphatic dicarboxylic acid or derivative thereof is chosen 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.

[0010] Specific examples of the 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- It is selected from one or more of undecanedicarboxylic acid, 1,10-decanedicarboxylic acid, undecanedioic acid, 1,12-dodecanedicarboxylic acid, hexadecanedioic acid, eicosanedioic acid, tetracosanedioic acid, dimer acid, or their ester derivatives or their anhydride derivatives, preferably one or more of succinic acid, adipic acid, sebacic acid, 1,12-dodecanedicarboxylic acid, or their ester derivatives or their anhydride derivatives, more preferably one or two of adipic acid, sebacic acid, or their ester derivatives or their anhydride derivatives, and most preferably adipic acid or its ester derivatives or its anhydride derivatives.

[0011] In the present invention, component a2) aromatic dicarboxylic acid or a derivative thereof is selected from one or a mixture of more than one of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or their ester derivatives or their anhydride derivatives, preferably terephthalic acid or its ester derivatives or its anhydride derivatives.

[0012] Specific examples of the 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 dicarboxylate, dimethyl 3,4'-phenylene sulfide dicarboxylate, dimethyl 4 ... The dicarboxylic acid is selected from one or more of terephthalic acid or an ester derivative or an anhydride derivative thereof, and is preferably terephthalic acid or an ester derivative or an anhydride derivative thereof.

[0013] In the present invention, the second component B is selected from one or more of ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol, preferably ethylene glycol, 1,3-propanediol or 1,4-butanediol.

[0014] Most preferably, when component a1) is adipic acid or its ester derivatives or its anhydride derivatives and component a2) is terephthalic acid or its ester derivatives or its anhydride derivatives, the second component B is a combination of 1,4-butanediol.

[0015] Based on the total molar amount of the first component A, the semi-aromatic polyester according to the present invention also contains a third component C in an amount of 0.01 to 5.0 mol % and a fourth component D in an amount of 0.01 to 5.0 mol %.

[0016] 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 anhydride, 1,2,4,5-benzenetetracarboxylic acid, or pyromellitic dianhydride, preferably trimethylolpropane, pentaerythritol or glycerin.

[0017] The fourth component D is a chain extender, which is one or more mixtures of isocyanates, isocyanurates, peroxides, epoxides, oxazolines, oxazines, lactams, carbodiimides, or polycarbodiimides containing two or more functional groups.

[0018] 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.

[0019] More preferably, the aromatic diisocyanate is diphenylmethane 2,2'-diisocyanate, diphenylmethane 2,4'-diisocyanate, or diphenylmethane 4,4'-diisocyanate.

[0020] The isocyanate containing two or more functional groups may be tris(4-isocyanato-phenyl)methane, which has three rings.

[0021] 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 methylene bis(4-isocyanatocyclohexane), most preferably hexamethylene 1,6-diisocyanate or isophorone diisocyanate.

[0022] Preferably, the isocyanurate having two or more functional groups is an aliphatic isocyanurate derived from an alkylene diisocyanate or a cycloalkylene diisocyanate having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, such as isophorone diisocyanate or methylene bis(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.

[0023] 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.

[0024] Preferably, the epoxide having two or more functional groups is preferably 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, or 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.

[0025] The epoxides having two or more functional groups are also preferably copolymers based on styrene, acrylic esters and / or methacrylic esters and containing epoxy groups, the epoxy groups being preferably glycidyl methacrylate. Compounds which have proved 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 polymers is preferably between 150 and 3000 g / eq, more preferably between 200 and 500 g / eq. The weight-average molecular weight Mw of the polymer is preferably between 2000 and 25000, more preferably between 3000 and 8000. The number-average molecular weight Mn of the polymer is preferably between 400 and 6000, more preferably between 1000 and 4000. The polydispersity index (Q=Mw / Mn) is preferably between 1.5 and 5.

[0026] The oxazolines and oxazines having two or more functional groups are preferably dioxazolines or dioxazines, the bridging moieties of which are single bonds, (CH 2)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, dioxazolines include 2,2'-bis(2-oxazoline), bis(2-oxazolinyl)methane, 1,2-bis(2-oxazolinyl)ethane, 1,3-bis(2-oxazolinyl)propane, 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 The 2,2'-diphenylenebis(oxazoline), 2,2'-decamethylenebis(2-oxazoline), 2,2'-ethylenebis(4-methyl-2-oxazoline), 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).

[0027] More preferred is 1,4-bis(2-oxazolinyl)benzene, 1,2-bis(2-oxazolinyl)benzene, or 1,3-bis(2-oxazolinyl)benzene.

[0028] 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 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.

[0031] Preferably, the carboxyl group content of the semi-aromatic polyester is from 5 to 60 mmol / kg, preferably from 10 to 30 mmol / kg.

[0032] The present invention also provides a method for preparing the above semi-aromatic polyester, the method comprising the steps of: a step S1 of adding a1 in the first component A and the second component B to a slurry blending kettle according to a 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 carrying out 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 according to a 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 carrying out 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, carrying out a primary polycondensation reaction on the esterification product Ba1 of step S1 at a reaction temperature of 170-220°C and a pressure of 1-10 kPa, and carrying out a primary polycondensation reaction on the esterification product Ba2 of step S1 at a reaction temperature of 230-270°C and a pressure of 1-10 kPa, and carrying out a primary polycondensation reaction on both of them independently until each reaction product reaches a viscosity number of 15-60 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution of 1:1 by weight according to the GB / T 17931-1999 standard, to obtain primary polycondensation products Pre-Ba1 and Pre-Ba2, respectively; Step S3: transferring the product Pre-Ba1 of the first polycondensation reaction obtained in step S2 to a first final polymerization kettle having a reaction temperature of 180-230°C and a pressure of 10-500 Pa, and transferring the product Pre-Ba2 of the first polycondensation reaction obtained in step S2 to a second final polymerization kettle having a reaction temperature of 220-270°C and a pressure of 10-500 Pa, and performing polycondensation reactions on both of them independently until the reaction products reach a viscosity number of 50-180 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution of 1:1 by weight according to the 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 150-300 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 the GB / T 17931-1999 standard.

[0033] Preferably, in S1, when preparing the Ba2 esterification product, 0.001-1% of the catalyst is added by weight of the final semi-aromatic polyester. Preferably, the catalyst is added by 0.02-0.2% by weight of the final semi-aromatic polyester. Controlling the catalyst amount can make the subsequent processing process more stable. In addition, the catalyst may be a tin compound, an antimony compound, a cobalt compound, a lead compound, a zinc compound, an aluminum compound or a titanium compound, more preferably a zinc compound, an aluminum compound or a 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 amount remaining in the product or downstream products is less toxic. This property is particularly important in biodegradable polyesters, since they enter the environment directly in the form of compost bags or coated films.

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

[0035] 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 the excess second component B is recovered through a purification device (usually a distillation column) connected to the esterification reactor and enters the esterification reactor. The amount of the recovered second component B is usually 20 to 50% by weight of the amount of fresh second component B.

[0036] 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.

[0037] In S2, when preparing the Pre-Ba2 prepolymer, the remaining catalyst in 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.

[0038] In S2, when Pre-Ba1 and Pre-Ba2 are respectively prepared, the general reaction time is 2-5 hours, and under normal circumstances, after this reaction time, the primary polycondensation reaction products Pre-Ba1 and Pre-Ba2 can be produced with a viscosity number of 15-60ml / g measured in a constant temperature water bath at 25±0.05℃ in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard. The carboxyl group content of the primary polycondensation reaction products Pre-Ba1 and Pre-Ba2 after the S2 reaction is usually 10-60mmol / kg.

[0039] In the polycondensation reaction step S3, a passivator can be mixed into the prepolyester as necessary. Usable passivators are typically phosphorus compounds including phosphoric acid, phosphorous acid, and their esters. Based on the weight of the final polyester, the amount of the passivator is typically 0.001 to 0.1% by weight, preferably 0.01 to 0.05% by weight.

[0040] In S3, when preparing the Poly-Ba1 polyester, the reaction temperature is more preferably 190 to 220° C., and the reaction pressure is more preferably 50 to 200 Pa.

[0041] In S3, when preparing the Poly-Ba2 polyester, the reaction temperature is more preferably 240 to 260° C., and the reaction pressure is more preferably 20 to 100 Pa.

[0042] In S3, the reaction time of polycondensation is preferably 1-5 hours, more preferably 2-4 hours. The produced Poly-Ba1 and Poly-Ba2 polyesters have a viscosity number of 50-180 ml / g measured in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 in a constant temperature water bath at 25±0.05°C according to the GB / T 17931-1999 standard. In addition, the carboxyl group content of the Poly-Ba1 and Poly-Ba2 polyesters after the S3 reaction is usually 5-60 mmol / kg, more preferably 10-30 mmol / kg.

[0043] In S4, the mixing of Poly-Ba1 and Poly-Ba2 is carried out in a mixer, which includes a raw material injection system, a temperature control system, a high shear homogenizing pump and a homogenizer, the temperature range of the mixer is 200°C-280°C, preferably 240°C-260°C, and the residence time of Poly-Ba1 and Poly-Ba2 in the mixer is 1-4 hours, preferably 1.5-2 hours. After passing through the mixer, the obtained reaction product reaches a viscosity number of 150-300 ml / g, measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0044] Preferably, the preparation method optionally further includes 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 200-270°C, the reaction residence time is 0.5-15 minutes, preferably 2-5 minutes, and the reaction is completed when the reaction product reaches a viscosity number of 150-350 ml / g, as measured in a phenol / o-dichlorobenzene solution of 1:1 by weight according to GB / T 17931-1999 standard in a constant temperature water bath at 25±0.05°C.

[0045] In the process of the present invention, aliphatic diacids and aromatic diacids are polymerized independently before the chain extension step, and aliphatic polyester oligomers and aromatic polyester oligomers are mixed in the chain extension step. The double bond content of the resulting semi-aromatic polyester is 0.55-4.5mmol / kg, and therefore has good melt heat retention stability and good color.

[0046] The above-mentioned semi-aromatic polyester of the present invention can also be prepared via other processes, such as directly copolymerizing a double bond-containing compound (such as undecylenic acid) during the synthesis process to control the double bond content of the semi-aromatic polyester to 0.55-4.5 mmol / kg.

[0047] The present invention also provides the application of said semi-aromatic polyester in the manufacture of compostable and degradable products, the compostable and degradable products can be fibers, films or containers, etc.

[0048] 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% by weight of additives and / or other polymers; and 0-70% by weight of reinforcing material and / or filler.

[0049] As a specific option, the additive and / or other polymer may be at least one or more components selected from aliphatic polyesters, polycaprolactones, starches, celluloses, polyhydroxyalkanoates, and polylactic acids.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention provides a semi-aromatic polyester, which has a specific double bond content and has better melt heat residence stability and good color compared to known semi-aromatic polyesters. [Brief description of the drawings]

[0052] [Figure 1] 1 is a 1H NMR pattern of the semi-aromatic polyester obtained in Example 1. [Diagram 2] FIG. 2 is an enlarged view of a double bond peak portion in the 1H NMR spectrum of the semi-aromatic polyester obtained in Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] 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 the examples, but the embodiment of the present invention is not limited to the following examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention should be in the equivalent substitution form, and all are included in the protection scope of the present invention. In addition, "parts" and "%" in this specification mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0054] Performance test method: Test method for double bond content in semi-aromatic polyester (taking PBAT obtained by the reaction of terephthalic acid, adipic acid and 1,4-butanediol in Example 1 as an example): A 20 mg sample of the semi-aromatic polyester was dissolved in 0.6 ml of deuterated chloroform and analyzed using a Bruker AV 500 nuclear magnetic resonance spectrometer. 1 H NMR was measured and the peak of the chloroform solvent was set at 7.26 ppm. Referring to the literature (J. Appl. Polym. Sci. 2007, 104(4):2643-2649.), the four hydrogen atoms of the benzene ring in the terephthalic acid repeating unit appear at around 8.10 ppm, and the two CH 2 It can be seen that the four hydrogen atoms of the unit appear around 2.33 ppm, as shown in Figure 1. The molar content of the diacid component is determined by the integrated area (I T and I A ) can be expressed as Molar content of terephthalic acid in PBAT = I T I(I T +I A )×100% Adipic acid molar content in PBAT = I A I(I T +I A )×100%

[0055] 3-Buten-1-ol (CAS: 627-27-0) in the literature and SDBS database 1 Referring to the HNMR spectrum, peak 1 at 5.0 to 5.2 ppm corresponds to two hydrogen atoms CH on the methylene group at the end of the double bond. 2 Peak 2 at 5.7-5.9 ppm is the hydrogen atom CH on the double bond methine group. 2 This is clearly the peak of =CH-, as shown in Figure 2.

[0056] Since the double bond content of semi-aromatic polyester is low, the double bond content C (unit: mmol / kg) can be calculated based on the peaks of the two hydrogen atoms on the terminal methylene groups of the double bonds as follows:

number

[0057] Viscosity number of semi-aromatic polyesters: 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.

[0058] 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) = AN / 56 x 10 3 was determined. The solvent mixture used contained 1 part by volume DMSO, 8 parts by volume isopropyl alcohol, and 7 parts by volume toluene. The semi-aromatic polyester sample was heated to 70 °C to dissolve all the polymer into a clear solution, and the solution temperature was kept between 60 and 70 °C to avoid polymer precipitation in the titration process. Tetrabutylammonium hydroxide was used as the titrant to avoid the use of highly toxic tetramethylammonium hydroxide. At the same time, the mixed solvent was used to reduce the CO in the air. 2 In order to prevent the blank solvent from absorbing CO 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 is heated to 70°C and then kept at a constant temperature for 0.5 hours, so that the blank solvent after heating will further absorb the CO in the air. 2 To prevent absorption of ions, a blank solvent was titrated immediately thereafter with alkaline solution.

[0059] Melt heat retention stability test: GB / T 3682.1-2018 Plastics Part 1 of the standard method for determining melt mass-flow rate and melt volume-flow rate in thermoplastics: The melt index MFR of semi-aromatic polyester was measured. The test temperature was 190℃ and the load was 2.16kg. When the melting time was 5 minutes, the melt index was obtained, which was called the MFR 0 When the melting time is 20 minutes, the melt index is obtained and is recorded as MFR 1 The heat retention melt index retention rate R = MFR 0 / MFR1 × 100% could be obtained. The lower the R value, the worse the heat retention stability.

[0060] Semi-aromatic polyester colors: The pelletized and dried samples were taken and tested according to GB / T 14190-2017 5.5.2, Method B (Dry Method). The L, a, b values ​​of Hunter Lab color system were obtained to define Hunter whiteness. WH=100-[(100-L) 2 +a 2 +b 2 ] 1 / 2 The higher the Hunter whiteness value, the better the color of the sample.

[0061] Example 1: S1. 437 kg / h of adipic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h. At the same time, 0.60 kg / h of glycerin and 0.224 kg / h of n-butyl titanate were added. The pressure of 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 to obtain an esterification product Ba1.

[0062] 437 kg / h of terephthalic acid and 356 kg / h of 1,4-butanediol were continuously added to the slurry preparation vessel, and the prepared slurry was continuously supplied to the second esterification reactor. The flow rate of 1,4-butanediol from the bottom of the process tower via a separate route was set to 119 kg / h. At the same time, 0.53 kg / h of glycerin and 0.406 kg / h of n-butyl titanate were added, and 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 to obtain the esterification product Ba2.

[0063] S2. The esterification product Ba1 is transferred to the first preliminary polycondensation reaction kettle, and 0.096 kg / h of n-butyl titanate and 0.245 kg / h of triphenyl phosphate are added at the same time. The temperature is 200°C, the pressure of the reaction kettle is 4 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba1 reaches a viscosity number of 44 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0064] The esterification product Ba2 was transferred to the second pre-polycondensation reaction kettle, and 0.174 kg / h of n-butyl titanate and 0.44 kg / h of triphenyl phosphate were added at the same time, the temperature was 250°C, the pressure of the reaction kettle 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 number of 27 ml / g, which was measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0065] S3. The prepolymer Pre-Ba1 was fed into the first final polymerization kettle through a melt pump, and the temperature of the first final polymerization kettle was 220°C, the pressure was 120 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity number of 138 ml / g, measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0066] The prepolymer Pre-Ba2 was fed to the second final polymerization kettle through a melt pump, and the temperature of the second final polymerization kettle was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity number of 115 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0067] S4. The two final polymerization products Poly-Ba1 and Poly-Ba2 were continuously fed into a mixer, the temperature of the mixer was 250° C. and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, while 5.2 kg / h of hexamethylene diisocyanate (HDI) was metered in at the same time, the temperature was set at 240° 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.

[0068] Example 2: S1. 605 kg / h of sebacic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h. At the same time, 0.60 kg / h of glycerin and 0.224 kg / h of n-butyl titanate were added. The pressure of the reactor was controlled to 40 kPa (absolute pressure), the temperature to 180°C, and the residence time to 2 to 4 hours. The water, tetrahydrofuran, and butanediol produced by the reaction were removed to obtain an esterification product Ba1.

[0069] 437 kg / h of terephthalic acid and 356 kg / h of 1,4-butanediol were continuously added to the slurry preparation vessel, and the prepared slurry was continuously supplied to the second esterification reactor. The flow rate of 1,4-butanediol from the bottom of the process tower via a separate route was set to 119 kg / h. At the same time, 0.53 kg / h of glycerin and 0.406 kg / h of n-butyl titanate were added, and 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 to obtain the esterification product Ba2.

[0070] S2. The esterification product Ba1 is transferred to the first preliminary polycondensation reaction kettle, and 0.096 kg / h of n-butyl titanate and 0.245 kg / h of triphenyl phosphate are added at the same time. The temperature is 190°C, the pressure of the reaction kettle is 4 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba1 reaches a viscosity number of 46 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0071] The esterification product Ba2 was transferred to the second pre-polycondensation reaction kettle, and 0.174 kg / h of n-butyl titanate and 0.44 kg / h of triphenyl phosphate were added at the same time, the temperature was 250°C, the pressure of the reaction kettle was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba2 reached a viscosity number of 29 ml / g, which was measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0072] S3. The prepolymer Pre-Ba1 was fed into the first final polymerization kettle through the melt pump, and the temperature of the first final polymerization kettle was 210℃, the pressure was 120 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity number of 147ml / g measured in a constant temperature water bath at 25±0.05℃ in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0073] The prepolymer Pre-Ba2 was fed to the second final polymerization kettle through a melt pump, and the temperature of the second final polymerization kettle was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity number of 119 ml / g, measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0074] 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 1.4 hours. The resulting polyester was then introduced into a twin-screw extruder, while 5.2 kg / h of hexamethylene diisocyanate (HDI) was metered in and the temperature was set at 240° 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.

[0075] Example 3: S1. 437 kg / h of adipic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h. At the same time, 0.88 kg / h of trimethylolpropane (TMP) and 0.224 kg / h of n-butyl titanate were added, and the pressure of 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 to obtain an esterification product Ba1.

[0076] 437 kg / h of terephthalic acid and 356 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 from the bottom of the process tower via a separate route was set to 119 kg / h. At the same time, 0.772 kg / h of trimethylolpropane and 0.406 kg / h of n-butyl titanate were added, and 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 to obtain an esterification product Ba2.

[0077] S2. The esterification product Ba1 is transferred to the first preliminary polycondensation reaction kettle, and 0.096 kg / h of n-butyl titanate and 0.245 kg / h of triphenyl phosphate are added at the same time. The temperature is 200°C, the pressure of the reaction kettle is 4 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba1 reaches a viscosity number of 42 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0078] The esterification product Ba2 was transferred to the second pre-polycondensation reaction kettle, and 0.174 kg / h of n-butyl titanate and 0.44 kg / h of triphenyl phosphate were added at the same time, the temperature was 250°C, the pressure of the reaction kettle 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 number of 25 ml / g, which was measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0079] S3. The prepolymer Pre-Ba1 was fed into the first final polymerization kettle through a melt pump, and the temperature of the first final polymerization kettle was 220°C, the pressure was 120 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity number of 129 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0080] The prepolymer Pre-Ba2 was fed to the second final polymerization kettle through a melt pump, and the temperature of the second final polymerization kettle was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity number of 111 ml / g, measured in a constant temperature water bath at 25±0.05°C in a 1:1 weight ratio phenol / o-dichlorobenzene solution according to the GB / T 17931-1999 standard.

[0081] S4. The two final polymerization products Poly-Ba1 and Poly-Ba2 were continuously fed into a mixer, the temperature of the mixer was 250° C. and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, while 5.2 kg / h of hexamethylene diisocyanate (HDI) was metered in at the same time, the temperature was set at 240° 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.

[0082] Example 4: S1. 437 kg / h of adipic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h, and at the same time, 0.224 kg / h of n-butyl titanate was added. The pressure of 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 to obtain an esterification product Ba1.

[0083] 437 kg / h of terephthalic acid and 356 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 from the bottom of the process tower via a separate route was set to 119 kg / h, and simultaneously 0.406 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 to obtain an esterification product Ba2.

[0084] S2. The esterification product Ba1 is transferred to the first preliminary polycondensation reaction kettle, and 0.096 kg / h of n-butyl titanate and 0.245 kg / h of triphenyl phosphate are added at the same time. The temperature is 200°C, the pressure of the reaction kettle is 4 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba1 reaches a viscosity number of 49 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0085] The esterification product Ba2 was transferred to the second pre-polycondensation reactor, and 0.174 kg / h of n-butyl titanate and 0.44 kg / h of triphenyl phosphate were added at the same time, the temperature was 250°C, the pressure of the reactor was 2 kPa, and the residence time was 2-3 hours to extract the excess butanediol. At this time, the reaction product Pre-Ba2 reached a viscosity number of 35 ml / g, which was measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0086] S3. The prepolymer Pre-Ba1 was fed into the first final polymerization kettle through a melt pump, and the temperature of the first final polymerization kettle was 220°C, the pressure was 120 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity number of 141 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0087] The prepolymer Pre-Ba2 was fed to the second final polymerization kettle through a melt pump, and the temperature of the second final polymerization kettle was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity number of 120 ml / g, measured in a constant temperature water bath at 25±0.05°C in a 1:1 weight ratio phenol / o-dichlorobenzene solution according to the GB / T 17931-1999 standard.

[0088] S4. The two final polymerization products Poly-Ba1 and Poly-Ba2 were continuously fed into a mixer, the temperature of the mixer was 250° C. and the residence time was 1.5 hours. The resulting polyester was then introduced into a twin-screw extruder, while 5.2 kg / h of hexamethylene diisocyanate (HDI) was metered in at the same time, the temperature was set at 240° 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.

[0089] Example 5: S1. 437 kg / h of adipic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h. At the same time, 0.60 kg / h of glycerin and 0.224 kg / h of n-butyl titanate were added. The pressure of 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 to obtain an esterification product Ba1.

[0090] 437 kg / h of terephthalic acid and 356 kg / h of 1,4-butanediol were continuously added to the slurry preparation vessel, and the prepared slurry was continuously supplied to the second esterification reactor. The flow rate of 1,4-butanediol from the bottom of the process tower via a separate route was set to 119 kg / h. At the same time, 0.53 kg / h of glycerin and 0.406 kg / h of n-butyl titanate were added, and 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 to obtain the esterification product Ba2.

[0091] S2. The esterification product Ba1 is transferred to the first preliminary polycondensation reaction kettle, and 0.096 kg / h of n-butyl titanate and 0.245 kg / h of triphenyl phosphate are added at the same time. The temperature is 200°C, the pressure of the reaction kettle is 4 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba1 reaches a viscosity number of 42 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0092] The esterification product Ba2 was transferred to the second pre-polycondensation reactor, and 0.174 kg / h of n-butyl titanate and 0.44 kg / h of triphenyl phosphate were added at the same time, the temperature was 250°C, the pressure of the reactor 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 number of 28 ml / g, which was measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0093] S3. The prepolymer Pre-Ba1 was fed into the first final polymerization kettle through a melt pump, and the temperature of the first final polymerization kettle was 220°C, the pressure was 120 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity number of 140 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0094] The prepolymer Pre-Ba2 was fed to the second final polymerization kettle through a melt pump, and the temperature of the second final polymerization kettle was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity number of 125 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0095] 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 11.2 kg / h of N,N'-bis(2,6-diisopropylphenyl)carbodiimide (Stabaxol I) was metered in, the temperature was set at 240° 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.

[0096] Example 6: S1. 437 kg / h of adipic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h. At the same time, 0.60 kg / h of glycerin and 0.224 kg / h of n-butyl titanate were added. The pressure of 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 to obtain an esterification product Ba1.

[0097] 600 kg / h of terephthalic acid and 488 kg / h of 1,4-butanediol were continuously added to the slurry preparation kettle, and the prepared slurry was continuously supplied to the second esterification reactor. The flow rate of 1,4-butanediol from the bottom of the process tower via a separate route was set to 163 kg / h. At the same time, 0.73 kg / h of glycerin and 0.56 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. The water, tetrahydrofuran, and butanediol produced by the reaction were removed, and the obtained esterification product A1 was continuously extracted from the reactor to obtain the esterification product Ba2.

[0098] S2. The esterification product Ba1 is transferred to the first preliminary polycondensation reaction kettle, and 0.096 kg / h of n-butyl titanate and 0.245 kg / h of triphenyl phosphate are added at the same time. The temperature is 200°C, the pressure of the reaction kettle is 4 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba1 reaches a viscosity number of 47 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0099] The esterification product Ba2 is transferred to the second pre-polycondensation reaction kettle, and simultaneously 0.24 kg / h of n-butyl titanate and 0.60 kg / h of triphenyl phosphate are added, the temperature is 250°C, the pressure of the reaction kettle is 2 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba2 reaches a viscosity number of 35 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0100] S3. The prepolymer Pre-Ba1 was fed into the first final polymerization kettle through a melt pump, and the temperature of the first final polymerization kettle was 220°C, the pressure was 120 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity number of 132 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0101] The prepolymer Pre-Ba2 was fed to the second final polymerization kettle through a melt pump, and the temperature of the second final polymerization kettle was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity number of 119 ml / g, measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0102] 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, while 6.11 kg / h of hexamethylene diisocyanate (HDI) was metered in at the same time, the temperature was set at 240° 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.

[0103] Example 7: S1. 437 kg / h of adipic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h. At the same time, 0.60 kg / h of glycerin and 0.224 kg / h of n-butyl titanate were added. The pressure of 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 to obtain an esterification product Ba1.

[0104] 437 kg / h of terephthalic acid and 356 kg / h of 1,4-butanediol were continuously added to the slurry preparation kettle, and the prepared slurry was continuously supplied to the second esterification reactor. The flow rate of 1,4-butanediol from the bottom of the process tower via a separate route was set to 119 kg / h. At the same time, 0.53 kg / h of glycerin and 0.406 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. The water, tetrahydrofuran, and butanediol produced by the reaction were removed, and the obtained esterification product A1 was continuously extracted from the reactor to obtain the esterification product Ba2.

[0105] S2. The esterification product Ba1 is transferred to the first preliminary polycondensation reaction kettle, and 0.096 kg / h of n-butyl titanate and 0.245 kg / h of triphenyl phosphate are added at the same time. The temperature is 200°C, the pressure of the reaction kettle is 4 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba1 reaches a viscosity number of 40 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0106] The esterification product Ba2 was transferred to the second pre-polycondensation reaction kettle, and 0.174 kg / h of n-butyl titanate and 0.44 kg / h of triphenyl phosphate were added at the same time, the temperature was 250°C, the pressure of the reaction kettle was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba2 reached a viscosity number of 29 ml / g, which was measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0107] S3. The prepolymer Pre-Ba1 was fed into the first final polymerization kettle through a melt pump, and the temperature of the first final polymerization kettle was 220°C, the pressure was 120 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity number of 130 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0108] The prepolymer Pre-Ba2 was fed to the second final polymerization kettle through a melt pump, and the temperature of the second final polymerization kettle was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity number of 114 ml / g, measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0109] 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, while 5.2 kg / h of hexamethylene diisocyanate (HDI) was metered in and the temperature was set at 240° C. After a residence time of 6 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0110] Example 8: S1. 437 kg / h of adipic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h. At the same time, 0.60 kg / h of glycerin and 0.224 kg / h of n-butyl titanate were added. The pressure of 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 to obtain an esterification product Ba1.

[0111] 437 kg / h of terephthalic acid and 356 kg / h of 1,4-butanediol were continuously added to the slurry preparation kettle, and the prepared slurry was continuously supplied to the second esterification reactor. The flow rate of 1,4-butanediol from the bottom of the process tower via a separate route was set to 119 kg / h. At the same time, 0.53 kg / h of glycerin and 0.406 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. The water, tetrahydrofuran, and butanediol produced by the reaction were removed, and the obtained esterification product A1 was continuously extracted from the reactor to obtain the esterification product Ba2.

[0112] S2. The esterification product Ba1 is transferred to the first preliminary polycondensation reaction kettle, and 0.096 kg / h of n-butyl titanate and 0.245 kg / h of triphenyl phosphate are added at the same time. The temperature is 200°C, the pressure of the reaction kettle is 4 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba1 reaches a viscosity number of 43 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0113] The esterification product Ba2 was transferred to the second pre-polycondensation reaction kettle, and 0.174 kg / h of n-butyl titanate and 0.44 kg / h of triphenyl phosphate were added at the same time, the temperature was 250°C, the pressure of the reaction kettle 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 number of 25 ml / g, which was measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0114] S3. The prepolymer Pre-Ba1 was fed into the first final polymerization kettle through a melt pump, and the temperature of the first final polymerization kettle was 220°C, the pressure was 120 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity number of 133 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0115] The prepolymer Pre-Ba2 was fed to the second final polymerization kettle through a melt pump, and the temperature of the second final polymerization kettle was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity number of 112 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0116] 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, while 5.2 kg / h of hexamethylene diisocyanate (HDI) was metered in at the same time, the temperature was set at 240° C. After a residence time of 12 minutes, the polyester was pelletized using an underwater pelletizer and then dried to obtain the final polyester product.

[0117] Example 9: S1. 437 kg / h of adipic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h. At the same time, 0.60 kg / h of glycerin and 0.224 kg / h of n-butyl titanate were added. The pressure of 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 to obtain an esterification product Ba1.

[0118] 437 kg / h of terephthalic acid and 356 kg / h of 1,4-butanediol were continuously added to the slurry preparation kettle, and the prepared slurry was continuously supplied to the second esterification reactor. The flow rate of 1,4-butanediol from the bottom of the process tower via a separate route was set to 119 kg / h. At the same time, 0.53 kg / h of glycerin and 0.406 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. The water, tetrahydrofuran, and butanediol produced by the reaction were removed, and the obtained esterification product A1 was continuously extracted from the reactor to obtain the esterification product Ba2.

[0119] S2. The esterification product Ba1 is transferred to the first preliminary polycondensation reaction kettle, and 0.096 kg / h of n-butyl titanate and 0.245 kg / h of triphenyl phosphate are added at the same time. The temperature is 200°C, the pressure of the reaction kettle is 4 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba1 reaches a viscosity number of 47 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0120] The esterification product Ba2 was transferred to the second pre-polycondensation reaction kettle, and 0.174 kg / h of n-butyl titanate and 0.44 kg / h of triphenyl phosphate were added at the same time, the temperature was 250°C, the pressure of the reaction kettle was 2 kPa, and the residence time was 2-3 hours to extract excess butanediol. At this time, the reaction product Pre-Ba2 reached a viscosity number of 29 ml / g, which was measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0121] S3. The prepolymer Pre-Ba1 was fed into the first final polymerization kettle through a melt pump, and the temperature of the first final polymerization kettle was 220°C, the pressure was 120 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba1 reached a viscosity number of 136 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0122] The prepolymer Pre-Ba2 was fed to the second final polymerization kettle through a melt pump, and the temperature of the second final polymerization kettle was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Pre-Ba2 reached a viscosity number of 120 ml / g, measured in a constant temperature water bath at 25±0.05°C in a 1:1 weight ratio phenol / o-dichlorobenzene solution according to the GB / T 17931-1999 standard.

[0123] S4. The two final polymerization products Poly-Ba1 and Poly-Ba2 were continuously fed into a mixer, with the mixer temperature at 250°C and the residence time at 2 hours. Then, the polyesters were pelletized using an underwater pelletizer, and then dried to obtain the final polyester products.

[0124] Example 10: Under the protection of high purity nitrogen, 1951g of terephthaloyl chloride, 2000g of adipoyl chloride, and 0.73g of undecenoyl chloride (CAS: 38460-95-6) were dissolved in 2000ml of dichloromethane to obtain an acyl chloride solution, which was then stored in an ice bath and cooled to 0°C for later use. 1890g of 1,4-butanediol and 4240g of triethylamine were added to 3000ml of dichloromethane and stirred uniformly to obtain an alcohol amine solution. The above alcohol amine solution was slowly dripped into the acyl chloride solution, and the dripping speed was controlled so that the solution temperature was within 3°C, and the dripping was completed in about 1 hour. After dripping, the ice bath was removed and the reaction was allowed to proceed with stirring at room temperature for 24 hours. Next, the product was dripped into a mixture of triethylamine and ethanol (volume ratio 1:2), which caused a white precipitate to form. The mixture was left to stand, and after the precipitation was complete, it was filtered by suction. Then, it was washed several times with a mixture of triethylamine and ethanol and deionized water, respectively, and finally dried in a vacuum oven at 70 °C for 10 h to obtain a powdered polymer. The powdered polymer was extruded using a twin-screw extruder at an extrusion temperature of 240 °C, granulated, and the final polyester product was obtained after water-cooling and drying.

[0125] Comparative Example 1: S1. 437 kg / h of terephthalic acid, 437 kg / h of adipic acid, 760 kg / h of 1,4-butanediol, 1.13 kg / h of glycerin, and 0.63 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 from the bottom of the process tower via a separate route was set to 253 kg / h, and 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 to obtain an esterification product BA.

[0126] S2. The esterification product BA is introduced into the pre-polycondensation reaction kettle by gravity, and 0.27 kg / h of n-butyl titanate and 0.685 kg / h of triphenyl phosphate are added at the same time. The temperature is 250°C, the pressure of the reaction kettle is 2 kPa, and the residence time is 2-3 hours to extract excess butanediol. At this point, the reaction product Pre-BA reaches a viscosity number of 39 ml / g, which is measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to GB / T 17931-1999 standard.

[0127] S3. The prepolymer Pre-BA was fed into the disk reactor (i.e., the final polymerization reactor) through a melt pump, and the temperature of the final polymerization reactor was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Poly-BA reached a viscosity number of 133 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0128] S4. The obtained polyester was introduced into a twin-screw extruder, while 5.2 kg / h of hexamethylene diisocyanate (HDI) was metered in and the temperature was set at 240° 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.

[0129] Comparative Example 2: S1. 437 kg / h of adipic acid and 404 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 from the bottom of the process tower via a separate route was set to 135 kg / h. At the same time, 0.60 kg / h of glycerin and 0.224 kg / h of n-butyl titanate were added. The pressure of 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 to obtain an esterification product Ba1.

[0130] 437 kg / h of terephthalic acid and 356 kg / h of 1,4-butanediol were continuously added to the slurry preparation kettle, and the prepared slurry was continuously supplied to the second esterification reactor. The flow rate of 1,4-butanediol from the bottom of the process tower via a separate route was set to 119 kg / h. At the same time, 0.53 kg / h of glycerin and 0.406 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. The water, tetrahydrofuran, and butanediol produced by the reaction were removed, and the obtained esterification product A1 was continuously extracted from the reactor to obtain the esterification product Ba2.

[0131] S2. Two esterification products Ba1 and Ba2 were continuously fed into the mixer, the mixer temperature was 230℃, and the residence time was 30 minutes. The mixture flowing out of the mixer was introduced into the preliminary polycondensation reaction kettle by gravity, and at the same time, 0.27 kg / h of n-butyl titanate and 0.685 kg / h of triphenyl phosphate were added, the temperature was 250℃, the pressure of the reaction kettle was 2 kPa, and the residence time was 2-3 hours to extract the excess butanediol. At this point, the reaction product Pre-BA reached a viscosity number of 37 ml / g, which was measured in a constant temperature water bath at 25±0.05℃ in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0132] S3. The prepolymer Pre-BA was fed into the disk reactor (i.e., the final polymerization reactor) through a melt pump, and the temperature of the final polymerization reactor was 250°C, the pressure was 20 Pa, and the reaction time was 2-4 hours. At this point, the reaction product Poly-BA reached a viscosity number of 128 ml / g measured in a constant temperature water bath at 25±0.05°C in a phenol / o-dichlorobenzene solution with a weight ratio of 1:1 according to the GB / T 17931-1999 standard.

[0133] S4. The obtained polyester was introduced into a twin-screw extruder, while 5.2 kg / h of hexamethylene diisocyanate (HDI) was metered in and the temperature was set at 240° 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.

[0134] Comparative Example 3: Under the protection of high purity nitrogen, 2.36 kg of terephthalic acid, 2.36 kg of adipic acid, 4.38 kg of 1,4-butanediol, 6.1 g of glycerin, and 4.9 g of n-butyl titanate were charged into the reaction vessel, the temperature was raised to 240 ° C, and the temperature was kept constant for 120 minutes. Next, 3.7 g of triphenyl phosphate was charged. Within 60 minutes, the pressure in the reactor was reduced to less than 50 Pa, and the reaction was carried out at 260 ° C for 60 to 120 minutes. After that, high purity nitrogen was filled into the reaction vessel, 28.1 g of hexamethylene diisocyanate (HDI) was added, and the mixture was stirred at a constant temperature of 260 ° C for 5 minutes and then discharged. [Table 1] TIFF2024539396000004.tif128170

[0135] As can be seen from the above results, the double bond content of the semi-aromatic polyester of the present invention is controlled in the range of 0.55 to 4.5 mmol / kg, and the polyester has high heat retention melt index retention, high Hunter whiteness and good color.

[0136] In Comparative Example 1, a mixed esterification step is used in the whole process, and the polymerization temperature is relatively high, so that the part derived from the aliphatic polyester in the semi-aromatic polyester is prone to thermal degradation, and the resulting double bond content is high, the heat retention melt index retention rate is very low, and the color is poor.

[0137] In Comparative Example 2, the aliphatic polyester and the aromatic polyester were esterified independently, but the two were still mixed in the process after esterification, which had a certain effect on reducing the double bond content, improving the heat retention melt index retention rate and color, but the reaction time of the esterification stage took up a small proportion of the total polymerization reaction time, so the improvement effect was limited.

[0138] In Comparative Example 3, a batch process was used for production, resulting in a high double bond content, a low heat retention melt index retention, and poor color.

Claims

1. 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: a semi-aromatic polyester derived from repeating units consisting of a diol having 2 to 12 carbon atoms, the double bond content in the semi-aromatic polyester is 0.55 to 4.5 mmol / kg; Based on the total molar amount of the first component A, the semi-aromatic polyester further comprises 0.01 to 5.0 mol % of a third component C; The semi-aromatic polyester, wherein 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. 2. The 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 of these.

3. 2. The 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.

4. 2. The semi-aromatic polyester according to claim 1, wherein the second component B is selected from one or more of ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol.

5. The semi-aromatic polyester according to claim 1, characterized in that the component a1) is adipic acid or an ester derivative thereof or an anhydride derivative thereof, the component a2) is terephthalic acid or an ester derivative thereof or an anhydride derivative thereof, and the second component B is 1,4-butanediol.

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 fourth component D; 2. The semi-aromatic polyester of 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. 2. The semi-aromatic polyester according to claim 1, wherein the viscosity number of the semi-aromatic polyester is 150 to 350 ml / g, 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.

8. 2. The semi-aromatic polyester according to claim 1, wherein the carboxyl group content of the semi-aromatic polyester is 5 to 60 mmol / kg.

9. In weight percentage, 5 to 95 wt. % of the semi-aromatic polyester according to claim 1; 5 to 95% by weight of another polymer; and 0 to 70% by weight of a filler.

10. 10. The application of the semi-aromatic polyester according to claim 1 in the manufacture of a compostable degradable product, characterized in that the compostable degradable product is a fiber, a film or a container.

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