Bio-based butanediic acid composition and method for preparing the same, and polyester prepared therefrom

Abstract

This invention provides a bio-based butanediic acid composition, a method for preparing the same, and a polyester prepared with the same composition. [Solution] The bio-based butanediic acid composition comprises bio-based butanediic acid and metal ions, wherein the mass content of the metal ions in the bio-based butanediic acid composition is 10 to 350 ppm. By using the bio-based butanediic acid composition containing the metal ions as a polyester raw material and controlling the content of the metal ions in the bio-based butanediic acid composition within a specific range, the resulting polyester exhibits superior mechanical properties and thermal stability.

Description

[Technical Field]

[0001] The present invention relates to the technical field of polyester preparation, and more specifically to a bio-based butanediic acid composition, a method for preparing the same, and a polyester prepared thereby. [Background technology]

[0002] Butanediol (also known as succinic acid) is a C4 compound widely used in industries such as pharmaceuticals, agrochemicals, dyes, fragrances, paints, food, and plastics. It is also used in the synthesis of organic chemicals such as 1,4-butanediol, tetrahydrofuran, and γ-butyrolactone, as well as biodegradable materials such as polybutylene succinate (PBS), and expectations for its biological applications are rising. Compared to the production of butanediol from petroleum resources, the production of butanediol from biomass resources has advantages such as renewable raw materials, lower costs, less pollution, and the ability to solve environmental problems (e.g., the greenhouse effect), and has become a hot spot for research in recent years.

[0003] The production of butanediic acid from biomass resources is often carried out by fermentation, such as microbial transformation, or a combination of microbial and chemical transformation to synthesize butanediic acid. In microbial transformation, low pH values ​​can reduce or even halt the metabolic activity of microorganisms, leading to a decrease in the yield. Therefore, neutralizing agents are often used to control the pH of the fermentation system. Next, the neutralized butanediic acid fermentation liquid is purified to obtain a butanediic acid product with a purity exceeding 99%. However, the resulting high-purity butanediic acid product contains nitrogen elements from the biomass resources, nitrogen elements from microorganisms and enzymes, nitrogen elements such as ammonia used in the purification process, sulfur elements, inorganic acids, organic acids, and metal cations. Furthermore, the neutralizing agents include ammonia, ammonium carbonate, urea, alkali (earth) metal hydroxides (e.g., NaOH, KOH, Ca(OH)2, Mg(OH)2, etc.), and alkali (earth) metal carbonates (e.g., Na2CO3, K2CO3, CaCO3, MgCO3), which also cause nitrogen elements and metal ions to remain in the butanediic acid.

[0004] When the metal cation content in butanediic acid exceeds 600 ppm, the reaction activity of butanediic acid decreases, the quality of the resulting polyester deteriorates, and the thermal stability of the polyester worsens. In particular, during prolonged heat retention, the polyester decomposes thermally in processing equipment such as extruders and injection molding machines, resulting in a significant decrease in the performance of the molded product.

[0005] Therefore, developing a bio-based butanediic acid composition that improves the thermal stability of polyester and ensures that polyester maintains a high tensile strength even during long-term heat retention is an urgent issue that needs to be addressed in this field. [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention aims to provide a bio-based butanediic acid composition, a method for preparing the same, and a polyester prepared therefrom, in order to address the shortcomings of the prior art. This solves the problem of low thermal stability of polyesters prepared using bio-based butanediic acid as a raw material in the prior art. [Means for solving the problem]

[0007] To achieve this objective, the present invention employs the following technical solutions.

[0008] In a first aspect, the present invention provides a bio-based butanediic acid composition comprising bio-based butanediic acid and a metal ion, wherein the mass content of the metal ion in the bio-based butanediic acid composition is 10 to 350 ppm.

[0009] In this invention, a polyester prepared using a bio-based butanediic acid containing metal ions as a raw material, and by controlling the content of metal ions in the bio-based butanediic acid composition to a specific range, exhibits superior mechanical properties and thermal stability, as well as a lower melt index, under the same reaction conditions.

[0010] In the present invention, the mass content of metal ions in the bio-based butanediic acid composition is 10 to 350 ppm, and may be, for example, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm, 100 ppm, 110 ppm, 120 ppm, 130 ppm, 140 ppm, 150 ppm, 160 ppm, 170 ppm, 180 ppm, 190 ppm, 200 ppm, 210 ppm, 220 ppm, 230 ppm, 240 ppm, 250 ppm, 260 ppm, 270 ppm, 280 ppm, 290 ppm, 300 ppm, 310 ppm, 320 ppm, 330 ppm, 340 ppm, 350 ppm, or any of the above values.

[0011] Preferably, the mass content of metal ions in the bio-based butanediic acid composition is 20 to 280 ppm, more preferably 60 to 200 ppm.

[0012] In this invention, when the mass content of metal ions is within the above range, the resulting polyester exhibits superior mechanical properties and thermal stability. If the metal ion content is too high, it affects the reaction activity of butanediic acid, and further affects the properties of the polyester. Furthermore, obtaining bio-based butanediic acid with a low metal ion content is a highly desirable challenge for those skilled in the art. Achieving extremely low metal ion content (less than 10 ppm) requires multiple purification processes and expensive purification equipment, which is economically disadvantageous. The bio-based butanediic acid composition according to the present invention allows for the preparation of high-performance polyester materials without significantly increasing costs.

[0013] In this invention, a bio-based butanediic acid composition means that a portion of the main components of the butanediic acid composition are derived from biomass resources.

[0014] Preferably, the metal ion is Na + , K + Mg 2+ Ca 2+ This includes one or at least two combinations of the following.

[0015] In the present invention, the metal ions may be metal ions remaining in the process of preparing biobutanediic acid using biomass resources as raw materials, and a compound containing metal ions may be added externally as needed.

[0016] In this invention, when the metal ions are residual metal ions in the process of preparing bio-based butanediic acid using biomass resources as raw materials, the content of metal ions in the butanediic acid can be reduced by post-treatment, thereby bringing the content of metal ions in the final bio-based butanediic acid composition within a specific range. The post-treatment methods include extraction and cation exchange resin column adsorption.

[0017] Preferably, the metal ion is Na + , K + , Mg 2+ , and Ca 2+ .

[0018] Preferably, the mass content of Na + or K + in the bio-based succinic acid composition is 60 ppm or less, for example, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, 55 ppm, 60 ppm, or any range of the above values, and more preferably 2 to 50 ppm, still more preferably 5 to 30 ppm.

[0019] Preferably, the mass content of Mg 2+ in the bio-based succinic acid composition is 50 ppm or less, for example, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, or any range of the above values, and more preferably 5 to 40 ppm, still more preferably 10 to 30 ppm.

[0020] Preferably, the mass content of Ca 2+ in the bio-based succinic acid composition is 220 ppm or less, for example, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm, 100 ppm, 110 ppm, 120 ppm, 130 ppm, 140 ppm, 150 ppm, 1X0 ppm, 170 ppm, 180 ppm, 190 ppm, 200 ppm, 210 ppm, 220 ppm, or any range of the above values, and more preferably 20 to 170 ppm, still more preferably 70 to 130 ppm.

[0021] Preferably, under the conditions of a temperature of 25°C and a concentration of 0.1 mol / L, the pH value of the aqueous solution of the bio-based succinic acid composition is 2.8 or less, for example, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, 2, 2.1, 2.2, 2.3, 2.4, 2.5, or within the range of any of the above values. More preferably, the pH value is 2.6 or less, and particularly preferably 2.4 or less.

[0022] Generally, under the conditions of 25°C and a concentration of 0.1 mol / L, the pH value of succinic acid is 2.7. When synthesizing an aliphatic polyester by reacting succinic acid with butanediol, the lower the pH value of the system, the more advantageous it is for improving the reaction activity, reaction efficiency, and degree of reaction. The polymerization residence time is shortened, and an aliphatic polyester with improved quality indicators such as acid value and color value and improved thermal stability can be obtained. In the present invention, when a neutralizing agent is used to adjust the pH of the fermentation system, the pH value of the aqueous solution of the bio-based succinic acid composition can be lowered by adjusting the addition amount of the neutralizing agent. By using a bio-based succinic acid composition with a low pH value as a raw material, a polyester with more excellent properties can be prepared. Preferably, the pH value of the aqueous solution of the bio-based succinic acid composition is 2.6 or less.

[0023] In a second aspect, the present invention provides a method for preparing the bio-based succinic acid composition according to the first aspect, and the preparation method includes: Step (1) of preparing a succinic acid stock solution using biomass resources as a raw material, and Step (2) of purifying the succinic acid stock solution obtained in step (1) to obtain the bio-based succinic acid composition, wherein the purification method includes an extraction method and a cation exchange resin column adsorption method.

[0024] In the present invention, by extraction and purification using a cation exchange resin column in the preparation method, a bio-based succinic acid composition with high purity and a low content of metal ions can be obtained.

[0025] Preferably, the butanediic acid content in the butanediic acid stock solution is 70 to 95 g / L, and may be, for example, 70 g / L, 72 g / L, 75 g / L, 78 g / L, 80 g / L, 82 g / L, 85 g / L, 88 g / L, 90 g / L, 92 g / L, 95 g / L, or any of the above values.

[0026] Preferably, the extraction method includes forward cross flow extraction and reverse cross flow extraction.

[0027] Preferably, the extractant for the cross-flow extraction includes a phosphate-based extractant.

[0028] Preferably, the phosphate-based extractant comprises at least one of diisooctyl phosphate, diethyl phosphate, or triethyl phosphate.

[0029] In the present invention, the volume of the butanediic acid stock solution is 1 L, and the mass of the extractant in the cross-flow extraction is 20 to 55 g, for example, 20 g, 22 g, 24 g, 26 g, 28 g, 30 g, 32 g, 34 g, 36 g, 38 g, 40 g, 42 g, 44 g, 46 g, 48 g, 50 g, 52 g, 54 g, 55 g, or any of the above values, more preferably 25 to 45 g, and particularly preferably 30 to 40 g.

[0030] Preferably, the extractant for the inverse cross flow extraction is water.

[0031] In the present invention, the volume of the solution containing butanediic acid obtained by forward cross flow extraction is 1 L, and the mass of the extractant obtained by reverse cross flow extraction is 30 to 95 g, for example, 30 g, 32 g, 35 g, 38 g, 40 g, 42 g, 45 g, 48 g, 50 g, 52 g, 55 g, 58 g, 60 g, 62 g, 65 g, 68 g, 70 g, 72 g, 75 g, 78 g, 80 g, 82 g, 85 g, 88 g, 90 g, 92 g, 95 g, or any of the above values, more preferably 40 to 75 g, and particularly preferably 50 to 70 g.

[0032] In the present invention, the number of times the forward cross flow extraction and inverse cross flow extraction are performed is one or more, independently of each other, and may be, for example, 1, 2, 3, 4, 5, 6, 7, 8, or any of the above values.

[0033] Preferably, the cation exchange resin column is Na + , K + Mg 2+ Ca 2+ It can adsorb at least one of the following.

[0034] In the present invention, the cation exchange resin is a 732 type cation exchange resin, and the cation exchange resin includes, but is not limited to, AmberliteIR-120, Dowex-50, Germany: Lewatit-100, Japan: DiaionSK-1, etc.

[0035] Preferably, the column injection flow rate for the cation exchange resin column adsorption method may be 0.5 to 2.8 BV / h, for example, 0.5 BV / h, 0.6 BV / h, 0.8 BV / h, 1 BV / h, 1.1 BV / h, 1.2 BV / h, 1.3 BV / h, 1.4 BV / h, 1.5 BV / h, 1.6 BV / h, 1.7 BV / h, 1.8 BV / h, 1.9 BV / h, 2 BV / h, 2.1 BV / h, 2.2 BV / h, 2.3 BV / h, 2.4 BV / h, 2.5 BV / h, 2.6 BV / h, 2.7 BV / h, 2.8 BV / h, or any of the above values, more preferably 0.8 to 2 BV / h, and more preferably 1 to 1.3 BV / h.

[0036] In the present invention, the cation exchange resin column adsorption method further includes the step of eluting with water after passing through the cation exchange resin column.

[0037] Preferably, the mass of the water is 2 to 7 times the mass of the solution to be eluted, and may be, for example, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, or any of the above values.

[0038] In this invention, the elution target solution refers to the solution containing butanediic acid before passing it through the cation exchange resin.

[0039] Preferably, the biomass resources include plant resources and / or animal resources, with plant resources being preferred.

[0040] In this invention, the plant resources refer to biomass resources that can convert and store solar energy in the form of starch, cellulose, etc., through photosynthesis, and the animal resources refer to biomass resources that grow and develop by preying on plants. The plant resources or animal resources also include products obtained by processing the plant resources or animal resources.

[0041] In the present invention, the plant resources include, but are not limited to, wood, rice straw, rice husks, rice bran, old rice, corn, sugarcane, cassava, corn stalks, cassava starch residue, bagasse, vegetable oil residue, buckwheat, soybeans, and food waste.

[0042] In the present invention, the preparation method further includes the step of converting the biomass resource into a carbon source, and then preparing a butanediic acid stock solution using this carbon source as a raw material. The method for converting to a carbon source includes, but is not limited to, chemical treatment, physical treatment, and biological treatment. For example, the chemical treatment may include acid treatment (e.g., treatment with strong acids such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid), alkali treatment, ammonia freeze-steam explosion, solvent extraction, supercritical fluid treatment, and oxidizing agent treatment. The physical treatment may include pulverization, steam explosion, microwave treatment, and electron beam irradiation. The biological treatment may include microbial treatment and enzyme treatment.

[0043] In the present invention, the carbon source includes, but is not limited to, hexoses such as glucose, mannose, galactose, fructose, sorbose, and tagatose; pentoses such as arabinose, xylose, ribose, xylulose, and ribulose; and disaccharides or polysaccharides such as pentosan, sucrose, starch, and cellulose. Preferably, it is glucose, fructose, or xylose, and particularly preferably glucose.

[0044] Preferably, the method for preparing the butanediic acid stock solution in step (1) includes a microbial fermentation method and / or a chemical conversion method, with the microbial fermentation method being preferred.

[0045] In the present invention, the microorganisms used in the microbial fermentation method may be any microorganism capable of producing dicarboxylic acid, and examples include anaerobic bacteria, facultative anaerobic bacteria, and aerobic bacteria. For example, the anaerobic bacteria may be of the genus Anaerobiospirillum (US5143833A), the facultative anaerobic bacteria may be of the genus Actinobacillus (US5504004A) or Escherichia (US5770435A), and the aerobic bacteria may be of the genus Corynebacterium (Japanese Patent Publication No. 11-113588, CN103183813A). These documents are incorporated herein by reference, but preferably, aerobic bacteria such as those of the genus Corynebacterium are used.

[0046] Examples of Corynebacterium-type bacteria include microorganisms belonging to the genera Corynebacterium, Brevibacterium, or Arthrobacter. Of these, preferred microorganisms include those belonging to the genera Corynebacterium or Brevibacterium, and even more preferred microorganisms include those belonging to Corynebacterium glutamicum, Brevibacterium flavum, Brevibacterium ammoniagenes, or Brevibacterium lactofermentum.

[0047] In microbial conversion, low pH can lead to decreased or even complete cessation of microbial metabolic activity, potentially resulting in reduced yield or microbial death. Therefore, neutralizing agents are often used to adjust the pH of the fermentation system. Typically, a pH sensor is used to measure the pH within the reaction system, and then a neutralizing agent is added to adjust the pH to a predetermined range. The method of adding the neutralizing agent is not particularly limited; it may be added continuously or intermittently. The pH value can be adjusted to a range in which the activity of the microorganisms, such as bacterial cells or fungi, is most effectively expressed, depending on the type of microorganism used. Typically, the pH value is 4 to 10, preferably 6 to 9.

[0048] Neutralizing agents include ammonia, ammonium carbonate, urea, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, and alkaline earth metal carbonates. Ammonia, ammonium carbonate, and urea are preferred. Examples of alkali (earth) metal hydroxides include NaOH, KOH, Ca(OH)2, Mg(OH)2, or mixtures thereof, and examples of alkali (earth) metal carbonates include Na2CO3, K2CO3, CaCO3, MgCO3, or mixtures thereof.

[0049] In the present invention, a general method of the art may be used to prepare the butanediic acid stock solution using the biomass resources of step (1) as raw materials, for example, by referring to the method of CN118459331A.

[0050] Preferably, the purification method further includes activated carbon decolorization and / or filtration.

[0051] Preferably, in the activated carbon decolorization, the volume of the solution to be decolorized is 1 L, and the mass of the activated carbon is 0.5 to 10 g, for example, 0.5 g, 1 g, 2 g, 3 g, 4 g, 5 g, 5.2 g, 5.5 g, 5.8 g, 6 g, 6.2 g, 6.5 g, 6.8 g, 7 g, 7.2 g, 7.5 g, 7.8 g, 8 g, 8.5 g, 9 g, 9.5 g, 10 g, or any of the above values.

[0052] In the present invention, the decolorization target solution may be a stock butanediic acid solution, or a solution that has undergone other purification treatments, such as a solution obtained by performing at least one purification treatment of a stock butanediic acid solution, such as extraction, cation exchange resin column adsorption, or filtration.

[0053] Preferably, the activated carbon decolorization is performed at a temperature of 60-85°C for 30-65 minutes.

[0054] In the present invention, the filtration is performed using an ultrafiltration membrane, and the pore size of the ultrafiltration membrane is 20 to 80 nm, for example, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, or 80 nm, or any of the above values.

[0055] Preferably, the filtration temperature is 40 to 60°C, and may be, for example, 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, or any of the above values.

[0056] Preferably, the purification process further includes steps of vacuum distillation and / or cooling crystallization.

[0057] In this invention, the vacuum distillation is performed at a temperature of 65 to 75°C and a pressure of -0.07 to -0.1 MPa. When the butanediic acid content exceeds 15 wt%, the distillation is stopped, and the concentrated butanediic acid solution is cooled at a low temperature (8°C or below) to crystallize it, thereby obtaining the bio-based butanediic acid composition.

[0058] As a preferred technical solution of the present invention, the preparation method is: Step (1) prepares a butanediic acid stock solution with a butanediic acid content of 70-95 g / L using biomass resources as raw materials, Step (2) involves subjecting the butanediic acid stock solution obtained in step (1) to a forward cross-flow extraction with a phosphate-based extractant to obtain a butanediic acid-supported organic phase, and then subjecting the butanediic acid-supported organic phase to an inverse cross-flow extraction with water to obtain a butanediic acid aqueous solution, wherein the volume of the butanediic acid stock solution is 1 L, the mass of the phosphate-based extractant is 20-55 g, the volume of the butanediic acid-supported organic phase is 1 L, the mass of the water is 30-95 g, and the number of forward cross-flow extractions and inverse cross-flow extractions is one or more, independently of each other. (3) Step (3) is to pass the butanediic acid aqueous solution obtained in step (2) through a cation exchange resin column at a flow rate of 0.5 to 2.8 BV / h and elute it with 2 to 7 times the mass of water relative to the butanediic acid aqueous solution to obtain a butanediic acid effluent, wherein the elution is performed with 2 to 7 times the weight of water relative to the butanediic acid aqueous solution, Step (4) involves sequentially decolorizing the butanediic acid effluent obtained in step (3) with activated carbon and filtering to obtain a butanediic acid filtrate, wherein the volume of the butanediic acid effluent is 1 L, the mass of the activated carbon is 0.5 to 10 g, the decolorization with activated carbon is performed at a temperature of 60 to 85 °C for 30 to 65 min, and the filtration is performed using an ultrafiltration membrane at a filtration temperature of 30 to 60 °C. The process includes step (5) of obtaining the bio-based butanediic acid composition by vacuum distillation of the butanediic acid filtration obtained in step (4), cooling and crystallizing it.

[0059] In the present invention, the purification method includes the calcium salt method and the electrodialysis method.

[0060] In a third aspect, the present invention provides a polyester, wherein the raw material for preparing the polyester comprises the bio-based butanediic acid composition described in the first aspect.

[0061] Polyesters prepared using a specific bio-based butanediic acid composition of the present invention have a shorter residence time.

[0062] Preferably, the polyester is composed of the following: Set the total molar amount to 100 mol%, a1: 65-100 mol% of a bio-based butanediic acid and / or ester derivative thereof, a2: Component A is a dicarboxylic acid compound containing 0-35 mol% of adipic acid and / or its ester derivatives, The bio-based butanediol is a bio-based butanediol composition according to the first embodiment, comprising at least component A and component B which is 1,4-butanediol.

[0063] In the present invention, the molar ratio of component B to component A is (1 to 3):1, and may be, for example, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, or any of the above values, and more preferably (1 to 2):1.

[0064] In the present invention, "the polyester contains the following components" means that the molecular structure of the polyester contains structural units derived from component A and structural units derived from component B. "The dicarboxylic acid compound containing the following components" means that in the molecular structure of the polyester, the dicarboxylic acid structural unit portion contains structural units derived from component a1 and structural units derived from component a2.

[0065] In the present invention, the amount may be 65 to 100 mol%, for example, 65 mol%, 66 mol%, 68 mol%, 70 mol%, 72 mol%, 74 mol%, 76 mol%, 78 mol%, 80 mol%, 82 mol%, 84 mol%, 86 mol%, 88 mol%, 90 mol%, 92 mol%, 94 mol%, 96 mol%, 98 mol%, 100 mol%, or any of the above values ​​within a given range.

[0066] In this invention, the mol% range is 0 to 35 mol%, and may be, for example, 0 mol%, 2 mol%, 4 mol%, 6 mol%, 8 mol%, 10 mol%, 12 mol%, 14 mol%, 16 mol%, 18 mol%, 20 mol%, 22 mol%, 24 mol%, 26 mol%, 28 mol%, 30 mol%, 32 mol%, 34 mol%, 35 mol%, or any of the above values.

[0067] Preferably, the total molar amount of component A is 100 mol%, a1: 72-82 mol% of bio-based butanediic acid and / or its ester derivatives, a2: Contains a dicarboxylic acid compound comprising 18-28 mol% of adipic acid and / or its ester derivatives.

[0068] In the present invention, the derivative of succinate includes alkyl succinates, and exemplary the alkyl succinate may be at least one of dimethyl succinate, diethyl succinate, di-n-propyl succinate, diisopropyl succinate, di-n-butyl succinate, diisobutyl succinate, di-t-butyl succinate, di-n-pentyl succinate, diisopentyl succinate, and di-n-hexyl succinate. The alkyl succinate may also be an alkyl ester formed with butanediic acid or an alkyl ester formed with butanediic anhydride, and preferably dimethyl succinate formed with butanediic anhydride is used.

[0069] In the present invention, the derivative of the adipate includes alkyl adipates, and exemplary the alkyl adipate may be at least one of dimethyl adipate, diethyl adipate, di-n-propyl adipate, diisopropyl adipate, di-n-butyl adipate, diisobutyl adipate, di-t-butyl adipate, di-n-pentyl adipate, diisopentyl adipate, and di-n-hexyl adipate, and the alkyl adipate may be an alkyl ester formed with adipic acid, or an alkyl ester formed with adipic anhydride.

[0070] In the present invention, dicarboxylic acids or their ester derivatives may be used alone or in the form of a mixture of two or more.

[0071] In this invention, according to standard ISO 1133-2-2012, under conditions of 190°C and 2.16 kg, the melt index of the polyester is 8.0 g / 10 min or less, and more preferably 3 to 7.0 g / 10 min.

[0072] Preferably, the initial tensile strength of the polyester is 22 MPa or higher, and more preferably, 37 MPa or higher.

[0073] Preferably, when the polyester is kept warm for 10 minutes under conditions of 180°C, the tensile strength retention rate exceeds 70%, more preferably exceeds 82%, and particularly preferably exceeds 86%.

[0074] In the present invention, the polyester can be prepared using technical methods common in the art, and exemplary the method is: The method includes the steps of: esterifying component A and component B at a temperature of 140-220°C and a pressure of 0.5-2 bar for 1-6 hours to obtain an esterification product; pre-condensing the esterification product at a temperature of 220-270°C and a pressure of 0.1-1 bar for 40-120 minutes to obtain a pre-condensation polymerization product; and then polycondensing the pre-condensation polymerization product at a temperature of 230-280°C and a pressure of 1-5 mbar for 120-180 minutes, slicing and drying to obtain the polyester.

[0075] In the present invention, the raw materials for the esterification reaction further include a crosslinking agent, the crosslinking agent comprising at least one of tartaric acid, citric acid, malic acid, trimethylolpropane, trimethylolethane, pentaerythritol, polyethertriol, glycerin, 1,3,5-trimellitic acid, 1,2,4-trimellitic acid, 1,2,4-trimellitic anhydride, 1,2,4,5-benzenetetracarboxylic acid, or pyromellitic dianhydride, and with the mass of the finished polyester product being 100 wt%, the mass fraction of the crosslinking agent is 0.05 to 1 wt%.

[0076] In the present invention, the preliminary polymerization reaction further includes a catalyst, which 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, which may be tetrabutyl titanate or tetraisopropyl titanate, and the total mass of the catalyst is 0.001 to 1 wt% of the mass of the polycondensation product.

[0077] The polyester of the present invention is also biodegradable.

[0078] In this invention, a substance or mixture of substances is characterized as "biodegradable" if it exhibits a biodegradability of at least 90% as defined in DIN EN 13432.

[0079] Biodegradation typically means that polyester or polyester mixtures decompose within a reasonable timeframe. Decomposition proceeds by enzymatic degradation, hydrolysis, oxidative degradation, and / or exposure to electromagnetic radiation such as ultraviolet light, but most commonly by exposure to microorganisms such as bacteria, yeasts, fungi, and algae. Biodegradability can be quantified by mixing polyester with compost and storing it for a certain period. For example, according to DIN EN 13432:2000, during the composting process, CO2-free air is introduced into the mature compost, and the compost is exposed to a specific temperature profile. Here, biodegradability is defined as the percentage of biodegradation expressed as the ratio of the net amount of CO2 released from the sample (after subtracting the amount of CO2 released from compost without the sample) to the maximum amount of CO2 that the sample can release (calculated based on the carbon content in the sample).

[0080] Other methods for determining biodegradability are described in ASTM D5338:2021 and ASTM D6400:1999.

[0081] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and the need for simplicity, this invention does not fully list the specific point values ​​included in the above ranges. [Effects of the Invention]

[0082] Compared to the prior art, the present invention has the following beneficial effects.

[0083] Because the bio-based butanediic acid composition according to the present invention contains a specific amount of metal ions, polyesters prepared using the bio-based butanediic acid composition as a raw material have superior mechanical properties and thermal stability, retain high strength even after being treated at high temperatures for a certain period of time, and are low-cost. [Modes for carrying out the invention]

[0084] The technical solutions of the present invention will be further described below using specific embodiments. It will be apparent to those skilled in the art that the above embodiments are intended to aid in understanding the present invention and should not be considered to specifically limit it.

[0085] Unless otherwise specified, the raw materials used in this invention are as follows: 1,4-Butanediol: Purchased from Xinjiang Meike Chemical Co., Ltd., purity 99.7%. Glycerin: Purchased from Aladdin. Adipic acid: Purchased from Chongqing Huafeng Chemical Co., Ltd. Tetrabutyl titanate: Purchased from Jianyi Chemical Import & Export Co., Ltd. Type 732 cation exchange resin: Purchased from Tianjin Xijinna Environmental Protection Materials Technology Co., Ltd.

[0086] In the preparation method of the present invention, the concentrations of butanediic acid in the obtained stock solution, aqueous solution, and filtrate are tested by liquid chromatography. For specific test methods, refer to the method disclosed in CN118459331A.

[0087] Example 1

[0088] This embodiment provides a bio-based butanediic acid composition comprising bio-based butanediic acid and metal ions. The content of the bio-based butanediic acid, the composition and content of the metal ions are shown in Table 1, and the remainder in the composition is water and other impurity acids remaining during the process of preparing the butanediic acid composition.

[0089] This embodiment specifically provides a method for preparing a bio-based butanediic acid composition, comprising the following steps.

[0090] (1) A stock solution of butanediic acid with a butanediic acid content of 78 g / L was prepared using biomass resources as raw materials. The specific preparation method can be carried out by methods common in the field, for example, by referring to the method described in CN118459331A.

[0091] (2) After filtering the butanediic acid stock solution obtained in step (1), the volume of the butanediic acid stock solution was increased to 1 L, and 32 g of diisooctyl phosphate was added and a five-stage forward cross-flow extraction was performed to obtain a butanediic acid-supported organic phase. Then, the volume of the butanediic acid-supported organic phase was increased to 1 L, and a five-stage reverse cross-flow extraction was performed on the butanediic acid-supported organic phase using 65 g of deionized water to obtain an aqueous butanediic acid solution.

[0092] (3) The butanediic acid aqueous solution obtained in step (2) was passed through a cation exchange resin column at a flow rate of 1 BV / h, and eluted with 6 times the mass of water relative to the butanediic acid aqueous solution to obtain a butanediic acid effluent.

[0093] (4) The butanediic acid effluent obtained in step (3) was decolorized with activated carbon at 75°C for 60 min to reduce the volume of the butanediic acid effluent to 1 L, and the mass of the activated carbon was 8 g (i.e., the mass of the activated carbon was 8 g / L). Then, the mixture was filtered at 50°C using an ultrafiltration membrane with a pore size of 40 nm to obtain the butanediic acid filtrate.

[0094] (5) The distillation temperature was controlled to 70°C and the pressure to -0.07 to -0.1 MPa, and the butanediic acid filtrate obtained in step (4) was subjected to vacuum distillation. When the butanediic acid content exceeded 15 wt%, the distillation was stopped, and the concentrated butanediic acid solution was cooled at a low temperature (4°C) to crystallize, thereby obtaining white butanediic acid crystals, i.e., the bio-based butanediic acid composition.

[0095] Examples 2-6, Comparative Examples 1-6

[0096] Examples 2-6 and Comparative Examples 1-6 each provide bio-based butanediic acid compositions, the compositions and process parameters of which are shown in Tables 1 and 2. In the preparation method, steps (1) and (5) were the same as in Example 1. In Tables 1 and 2, the value corresponding to the type of extractant in step (2) is the mass (in g) of the extractant when the volume of the butanediic acid stock solution is 1 L, the value corresponding to deionized water is the mass (in g) of deionized water when the volume of the butanediic acid-supported organic phase is 1 L, and the amount of water used for elution in step (3) is a multiple of the mass of the butanediic acid aqueous solution.

[0097] Here, in Tables 1 and 2, " / " means that the ingredient is not included or that the step is not performed.

[0098] Example 7

[0099] This example provides a bio-based butanediic acid composition, the composition of which is shown in Table 1. The preparation method differs from that of Example 1 in that the butanediic acid stock solution is an aqueous solution of an equivolute amount of the bio-based butanediic acid composition provided in Comparative Example 1, and all other parameters were the same as in Example 1.

[0100] In this invention, the pH value of the bio-based butanediic acid composition is determined by the following method: 1.1800 ± 0.0020 g of the bio-based butanediic acid composition is weighed, added to 80 mL of deionized water, stirred until completely dissolved, transferred to a 100 mL volumetric flask, and deionized water is added up to the graduation line on the volumetric flask to obtain a 0.1 mol / L bio-based butanediic acid composition solution. The pH value of the bio-based butanediic acid composition solution is measured twice in parallel using a pH meter, and the average value is calculated to three decimal places.

[0101] The metal cation content in the butanediic acid composition is measured using ICP-OES analysis according to US EPA method 3052:1996 by the following procedure: Approximately 0.1 g of the bio-based butanediic acid composition is weighed, 5 mL of nitric acid is added to completely immerse the bio-based butanediic acid composition, 1.0 mL of hydrogen peroxide is added dropwise and the reaction is allowed to proceed for 2 minutes, then the mixture is sealed in a microwave decomposition vessel and decomposed at 210°C for 3 hours. After cooling to room temperature, the mixture is filtered through a 0.45 μm filtration membrane, diluted to 50 mL with distilled water, and tested by ICP-OES.

[0102] In this invention, the mass of bio-based butanediol in the bio-based butanediol composition is tested with reference to the method for determining the butanediol content in Section 4.3 of GB / T 34686-2017.

[0103] [Table 1]

[0104] [Table 2]

[0105] ND means that the relevant element was not detected.

[0106] Application Example 1

[0107] This application provides a polyester, the raw materials for preparing the polyester comprising 350 kg of 1,4-butanediol, 327 kg of butanediol, 1.8 kg of glycerin, and 0.38 kg of tetrabutyl titanate, wherein the butanediol is the bio-based butanediol composition provided in Example 1.

[0108] The method for preparing the polyester includes the following steps.

[0109] S1: Butanediol, 1,4-butanediol, and glycerin were physically mixed. After mixing was complete, the resulting mixture was transferred to an esterification reactor and esterified for 4 hours under conditions of 170°C and 1.0 bar to obtain the esterification product.

[0110] S2: The esterification product obtained in step S1 was transferred to a vertical reactor equipped with a stirrer, 0.38 kg of tetrabutyl titanate was added, and the reaction mixture was carried out as a pre-condensation polymerization reaction for 70 minutes under conditions of 250°C and a reactor pressure of 0.3 bar to obtain the pre-condensation polymerization product.

[0111] S3: The preliminary polymerization product obtained in step S2 was transferred to a horizontal reactor with a stirring device and subjected to polycondensation reaction for 160 minutes at a temperature of 253°C and a pressure of 2.5 mbar. The product was then sliced ​​and dried to obtain the polyester.

[0112] Application Examples 2-7

[0113] Examples 2-7 each provide a polyester, and the only difference from Example 1 is that the butanediic acid is a bio-based butanediic acid composition provided in Examples 2-7, while the remaining raw materials, amounts used, and preparation methods are all the same as in Example 1.

[0114] Application Example 8

[0115] Application Example 8 provides a polyester, which differs from Application Example 1 in that the total molar amount of dibasic acids is kept constant, containing 75 mol% butanediol and 25 mol% adipic acid, and further includes 350 kg of 1,4-butanediol, 2.8 kg of glycerin, and 0.52 kg of tetrabutyl titanate as raw materials for preparing the polyester, and the method for preparing the polyester includes the following steps.

[0116] S1: Butanediol, adipic acid, 1,4-butanediol, and glycerin were physically mixed. After mixing was complete, the resulting mixture was transferred to an esterification reactor and esterified for 3 hours at a temperature of 200°C and a pressure of 1.5 bar to obtain the esterification product.

[0117] S2: The esterification product obtained in step S1 was transferred to a vertical reactor equipped with a stirrer, tetrabutyl titanate was added, and the reaction mixture was carried out as a pre-condensation polymerization reaction for 100 minutes at 240°C and a reactor pressure of 0.5 bar to obtain the pre-condensation polymerization product.

[0118] S3: The preliminary polymerization product obtained in step S2 was transferred to a horizontal reactor with a stirring device and subjected to polycondensation reaction for 130 minutes at a temperature of 248°C and a pressure of 4 mbar. The product was then sliced ​​and dried to obtain the polyester.

[0119] Application Example 9

[0120] Application Example 9 provides a polyester, which differs from Application Example 1 in that the total molar amount of dibasic acids is kept constant, containing 66 mol% butanediol and 34 mol% adipic acid, and further includes 350 kg of 1,4-butanediol, 3.8 kg of glycerin, and 0.58 kg of tetrabutyl titanate as raw materials for preparing the polyester, and the method for preparing the polyester includes the following steps.

[0121] S1: Butanediol, adipic acid, 1,4-butanediol, and glycerin were physically mixed. After mixing was complete, the resulting mixture was transferred to an esterification reactor and esterified for 2 hours at a temperature of 210°C and a pressure of 1.8 bar to obtain the esterification product.

[0122] S2: The esterification product obtained in step S1 was transferred to a vertical reactor equipped with a stirrer, tetrabutyl titanate was added, and the reaction mixture was carried out as a pre-condensation polymerization reaction for 80 minutes at 260°C and a reactor pressure of 0.8 bar to obtain the pre-condensation polymerization product.

[0123] S3: The preliminary polymerization product obtained in step S2 was transferred to a horizontal reactor with a stirring device and subjected to polycondensation reaction for 150 minutes at a temperature of 252°C and a pressure of 3.5 mbar. The product was then sliced ​​and dried to obtain the polyester.

[0124] Comparative Application Examples 1-6

[0125] Comparative Application Examples 1-6 provide polyesters, and differ from Application Example 1 only in that the butanediic acid is a bio-based butanediic acid composition provided in Comparative Examples 1-6, respectively. The remaining raw materials, amounts used, and preparation methods were all the same as in Application Example 1.

[0126] Performance testing

[0127] (1) Melt Index: The melt index of the polyesters provided in Application Examples 1-9 and Comparative Application Examples 1-6 was tested at 190°C and 2.16 kg, with ISO 1133-2-2012 as the reference standard.

[0128] (2) The polyesters provided in Application Examples 1-9 and Comparative Application Examples 1-6 were injection molded into mechanical splines according to the GB / T 1040-92 standard. The temperatures of the first, second, third, and fourth sections of the injection molding machine were 180°C, 180°C, 180°C, and 180°C, respectively. The initial tensile strength of the splines (denoted as L0) and the tensile strength of the splines injected after being kept at 180°C for 10 minutes in the injection molding machine cavity (denoted as L1) were tested according to the standard ISO 527-2-2012, and the tensile strength retention rate (ΔL) was calculated as ΔL = L1 / L0 × 100%. The test conditions for tensile strength were an ambient temperature of 23±2°C and a tensile speed of 50 mm / min.

[0129] The specific test results are shown in Table 3.

[0130] [Table 3]

[0131] As can be seen from Table 3, polyesters prepared using a bio-based butanediic acid composition containing a specific amount of metal ions according to the present invention as a raw material have excellent mechanical properties and thermal stability, while also having a low melt index. In these polyesters, the melt index is 8.0 g / 10 min or less, the initial tensile strength is 22.1 MPa or more, and the tensile strength retention rate after being heated at 180°C for 10 minutes is 70.2% or more.

[0132] Comparative application examples revealed that the mechanical properties and thermal stability of polyesters obtained without using the bio-based butanedioic acid composition according to the present invention as a raw material were inferior to those of those in Application Examples 1-7.

[0133] The specific embodiments described above have further illustrated the objectives, technical solutions, and beneficial effects of the present invention. However, these are merely specific embodiments of the present invention and do not limit it. It should be understood that any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should also be included within the scope of protection of the present invention.

Claims

1. A bio-based butanediic acid composition comprising bio-based butanediic acid and a metal ion, A bio-based butanediic acid composition characterized in that the mass content of metal ions in the bio-based butanediic acid composition is 10 to 350 ppm.

2. The mass content of metal ions in the bio-based butanediic acid composition is 20 to 280 ppm. The aforementioned metal ion is Na ＋ _K ＋ Mg ２＋ Ca ２＋ The bio-based butanediic acid composition according to claim 1, characterized by comprising one or at least two of the following.

3. The aforementioned metal ion is Na ＋ _K ＋ Mg ２＋ , and Ca ２＋ Includes, Na in the bio-based succinic acid composition ＋ or K ＋ has a mass content of 60 ppm or less, Mg in the bio-based butanediic acid composition ２＋ The mass content is 50 ppm or less. Ca in the bio-based butanediic acid composition ２＋ The mass content is 220 ppm or less. The bio-based butanediic acid composition according to claim 1, characterized in that the pH value of the aqueous solution of the bio-based butanediic acid composition under the conditions of a temperature of 25°C and a concentration of 0.1 mol / L is 2.8 or less.

4. A method for preparing a bio-based butanediic acid composition according to any one of claims 1 to 3, wherein the preparation method is: Step (1) prepares a butanediic acid stock solution using biomass resources as raw materials, Step (2) involves purifying the butanediic acid stock solution obtained in step (1) to obtain the bio-based butanediic acid composition, The preparation method is characterized in that the purification method includes an extraction method and a cation exchange resin column adsorption method.

5. The butanediic acid content in the aforementioned butanediic acid stock solution is 70 to 95 g / L. The extraction methods include forward cross flow extraction and reverse cross flow extraction. The extractant for the aforementioned cross-flow extraction includes a phosphate-based extractant. The phosphate-based extractant comprises at least one of diisooctyl phosphate, diethyl phosphate, or triethyl phosphate. With a volume of butanediic acid stock solution of 1 L, the mass of the extractant in the cross-flow extraction is 20 to 55 g. The extractant for the aforementioned inverse cross flow extraction is water. The volume of the solution containing butanediic acid obtained by the forward cross flow extraction is 1 L, and the mass of the extractant obtained by the reverse cross flow extraction is 30 to 95 g. The number of times the aforementioned cross-flow extraction and reverse cross-flow extraction are performed is one or more, independently of each other. The aforementioned cation exchange resin column is Na ＋ _K ＋ Mg ２＋ Ca ２＋ It can adsorb at least one of the following: The column injection flow rate for the aforementioned cation exchange resin column adsorption method is 0.5 to 2.8 BV / h. In the aforementioned cation exchange resin column adsorption method, a step is employed in which the ions are passed through a cation exchange resin column and then eluted using water. The preparation method according to claim 4, characterized in that the mass of the water is 2 to 7 times the mass of the solution to be eluted.

6. The biomass resources include plant resources and / or animal resources. The method for preparing the butanediic acid stock solution in step (1) includes a microbial fermentation method and / or a chemical conversion method. The purification method further includes activated carbon decolorization and / or filtration. In the activated carbon decolorization described above, the volume of the solution to be decolorized is 1 L, and the mass of the activated carbon is 0.5 to 10 g. The activated carbon decolorization was performed at a temperature of 60 to 85°C and for a duration of 30 to 65 minutes. The preparation method according to claim 4, further comprising the steps of vacuum distillation and / or cooling crystallization after the aforementioned purification.

7. The aforementioned preparation method is Step (1) prepares a butanediic acid stock solution with a butanediic acid content of 70-95 g / L using biomass resources as raw materials, Step (2) is a step in which the butanediic acid stock solution obtained in step (1) is subjected to a forward cross-flow extraction with a phosphate-based extractant to obtain a butanediic acid-supported organic phase, and then the butanediic acid-supported organic phase is subjected to a reverse cross-flow extraction with water to obtain an aqueous butanediic acid solution, wherein the volume of the butanediic acid stock solution is 1 L, the mass of the phosphate-based extractant is 20 to 55 g, the volume of the butanediic acid-supported organic phase is 1 L, the mass of the water is 30 to 95 g, and the number of forward cross-flow extractions and reverse cross-flow extractions is one or more, independently of each other. Step (3) involves passing the butanediic acid aqueous solution obtained in step (2) through a cation exchange resin column at a flow rate of 0.5 to 2.8 BV / h, and eluting it with 2 to 7 times the mass of water relative to the butanediic acid aqueous solution to obtain a butanediic acid effluent. Step (4) involves sequentially decolorizing the butanediic acid effluent obtained in step (3) with activated carbon and filtering to obtain a butanediic acid filtrate, wherein the volume of the butanediic acid effluent is 1 L and the mass of the activated carbon is 0.5 to 10 g. The preparation method according to claim 4, characterized by comprising step (5) of subjecting the butanediic acid filtrate obtained in step (4) to vacuum distillation and cooling crystallization to obtain the bio-based butanediic acid composition.

8. A polyester characterized in that the raw material for preparing the polyester includes the bio-based butanediic acid composition described in any one of claims 1 to 3.

9. The aforementioned polyester has the following components: Set the total molar amount to 100 mol%, a1: 65-100 mol% of a bio-based butanediic acid and / or ester derivative thereof, a2: Component A is a dicarboxylic acid compound containing 0 to 35 mol% of adipic acid and / or its ester derivatives, The polyester according to claim 8, characterized by comprising at least component A and component B, which is 1,4-butanediol in equimolar amounts.

10. The polyester according to claim 8, characterized in that when kept warm for 10 minutes under conditions of 180°C, the tensile strength retention rate of the polyester exceeds 70%.

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