Preparation method of multifunctional biomass equol-based packaging material

Abstract

The invention discloses a preparation method of a multifunctional biomass equol-based packaging material. The preparation method comprises the following steps: reacting germanium oxide, stannous octoate, tetrabutyl titanate and triphenyl phosphite at a certain temperature to prepare a composite catalyst for preparing equol-based polyester; equol, dibasic acid / ester, dihydric alcohol and a composite catalyst are jointly put into a reaction kettle, and esterification reaction, pre-polycondensation reaction and final polycondensation reaction are performed to prepare the equol-based degradable polyester. The intrinsic viscosity of the obtained equol-based polyester is 0.7-1.3 dL / g, the bacteriostasis rate on escherichia coli is 30-70%, the tensile strength at break is 40-70 MPa, the oxygen permeation coefficient is 0.02-1.30 bar, the carbon dioxide permeation coefficient is 0.01-0.83 bar, the water vapor permeation coefficient is 0.0017-3.5 * 10 <-13 > g.cm / (cm.s.Pa), the 180-day degradation rate is larger than 60%, the comprehensive performance is remarkably superior to that of an existing degradable material, the variety of biomass polymer materials is expanded, and meanwhile, the antibacterial property of the equol-based polyester is improved. The defects of low mechanical strength, poor barrier property and the like of the current degradable material can be overcome, and the degradable material has a wide market prospect in the field of packaging materials.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material synthesis and application, and in particular to a method for preparing a multifunctional biomass equol-based packaging material. Background Art

[0002] The chemical name of equol is 7-hydroxy-3-(4-hydroxyphenyl)-chroman, which is a non-steroidal hormone. 14 H 15 O3 (Formula 1), is a heterocyclic structure containing two active hydroxyl groups and a relatively inactive oxygen in its central pyran ring, which can be chemically synthesized ( Bioorganic & Medicinal Chemistry, 2004, 12(6): 1559-1567. )、Microbial preparation( Journal of Food Processing and Preservation, 2019, 43 (11): e14205. ), biosynthesis ( Applied and Environmental Microbiology, 2013, 79 (11): 3494-3502. In recent years, researchers have focused on studying the pathways of natural microbial metabolism to produce equol, and have successively isolated strains related to equol metabolism from the feces of humans, mice, monkeys, pigs, and other animals, such as Asaccharobacter celatus , Adlercreutzia e-quolifaciens , Slackia isoflavoniconvertens, enterorhabdus mucosicola Some researchers have also achieved low-cost preparation of equol from biomass resources such as soybeans and kudzu root through separation, purification, and fermentation, which provides broad prospects for large-scale industrial production of equol. The research and development of its downstream derivatives has also become a key issue that needs to be urgently addressed.

[0003]

[0004] Formula 1 Molecular structure of equol Packaging materials refer to the general term for all materials used to manufacture packaging containers, constitute product packaging systems or assist in the packaging process. The raw materials used mainly include metals, plastics, glass, ceramics, natural fibers, etc. Among them, plastic products such as polyethylene and polypropylene have the characteristics of low cost, continuous production, and excellent comprehensive performance. They have been widely used in the field of food packaging, but their production raw materials rely on petrochemical resources and the products are non-degradable. Therefore, the development of biomass packaging materials with high strength, high barrier, and degradable functions has become a necessary path for the development of the green packaging industry. The biomass monomers that can currently be used to prepare high-performance packaging materials include: 2,5-furandicarboxylic acid, 2,5-furandimethanol, 2,5-tetrahydrofurandicarboxylic acid, 2,5-tetrahydrofurandimethanol, isosorbide, itaconic acid, vanillic acid, lactic acid, 1,3-propylene glycol, 1,10-decanedioic acid, etc. ( Green Chemistry, 2023, 25: 5836-5857.However, due to the limitations of molecular structure, when the above-mentioned biomass monomers are used to prepare degradable packaging materials, their mechanical strength and barrier properties cannot meet the requirements of multiple application scenarios. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a multifunctional biomass equol-based packaging material to solve the problem of limited application scenarios caused by the single type of biomass degradable packaging materials proposed in the above background technology and insufficient product strength, barrier and antibacterial properties.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing a multifunctional biomass equol-based packaging material, comprising the following steps: Step 1: preparing a composite catalyst for preparing a multifunctional biomass equol polyester material, wherein the raw materials for preparing the composite catalyst include germanium oxide, stannous octoate, tetrabutyl titanate and triphenyl phosphite; the molar ratio of the germanium oxide to the stannous octoate is 1:1-1:10; the molar ratio of the germanium oxide to the tetrabutyl titanate is 1:1-1:15; and the molar ratio of the germanium oxide to the triphenyl phosphite is 1:0.1-0.5; Step 2: The composite catalyst is prepared by the following method: i) mixing germanium oxide, stannous octoate, tetrabutyl titanate and triphenyl phosphite, and adding them together to petroleum ether, wherein the mass ratio of the germanium oxide to the petroleum ether is 1:50-1:100, and reacting at 120-180° C. for 10-24 hours; ii) Cooling the reactants to room temperature and filtering them, washing and drying them to obtain a white solid, which is the composite catalyst; Step 3: Add equol, linear aliphatic dibasic acid, linear aliphatic diester, and linear aliphatic diol into a reactor in proportion, and prepare a degradable equol-based polyester material through esterification, pre-condensation, and final polycondensation under the action of the composite catalyst.

[0007] Furthermore, the reaction temperature of step 2 is 120-150° C., and the reaction time is 16-20 h.

[0008] Furthermore, in step 2, the molar ratio of germanium oxide to stannous octoate is 1:1-1:5; the molar ratio of germanium oxide to tetrabutyl titanate is 1:1-1:10; the molar ratio of germanium oxide to triphenyl phosphite is 1:0.1-0.3; and the mass ratio of germanium oxide to petroleum ether is 1:80-1:100.

[0009] Furthermore, the method for preparing the degradable equol-based polyester material in step 3 specifically comprises the following steps: (1) Esterification reaction: under the protection of inert gas, equol, linear aliphatic dibasic acid, linear aliphatic dibasic ester, linear aliphatic diol and composite catalyst are added to the reactor, the reaction temperature is controlled within the range of 180-220 ° C, and the reaction time is 3-8 h; (2) Pre-condensation reaction: raise the temperature in the autoclave to 220-250°C, gradually reduce the vacuum degree to below 1000 Pa, and the reaction time should be no less than 1 hour; (3) Final polycondensation reaction: the temperature in the autoclave is raised to 220-260°C, the vacuum degree is gradually reduced to below 50 Pa, and the reaction time is 2-6 hours. After the final polycondensation is completed, the biodegradable equol polyester material is obtained through water cooling, granulation, and drying.

[0010] Furthermore, the linear aliphatic dibasic acid includes one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid; the linear aliphatic dibasic ester includes one or more of dimethyl carbonate, dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, dimethyl pimelate, dimethyl suberate, dimethyl azelaic acid, and dimethyl sebacate; the linear aliphatic diol includes one or more of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol.

[0011] Furthermore, the amount of the composite catalyst used is 0.01-0.5% of the total weight of the reaction system.

[0012] Furthermore, in step (1), after the feeding is completed, the air inside the reactor is evacuated by an inert gas replacement method. The esterification temperature is preferably 190-200° C., and the reaction time is preferably 4-6 h.

[0013] Furthermore, in step (2), the pre-condensation temperature is preferably 220-240° C., and the pre-condensation vacuum is respectively 8000 Pa, 5000 Pa, and 1000 Pa for 20 min.

[0014] Furthermore, in step (3), the final polycondensation temperature is preferably 230-250° C., and the reaction time is preferably 3-5 h.

[0015] Furthermore, the steps after the final polycondensation in step (3) are specifically as follows: using an inert gas to increase the pressure in the reaction system to 0.1-0.3 MPa, cutting the product melt into particles after water cooling, and then placing the particles in a vacuum oven at 80° C. and drying for 4 hours to obtain polyethylene terephthalate-co-terephthalate.

[0016] Beneficial effects: The present invention uses equol, a downstream derivative of renewable resources such as soybeans and kudzu root, as raw material, and adopts a melt polycondensation method to copolymerize high-rigidity biomass equol monomers with linear aliphatic dibasic acids, dibasic esters, and diols under the action of a high-efficiency composite catalyst. This method can produce a biomass equol polyester material with antibacterial properties, high strength, and high barrier properties (with an intrinsic viscosity of 0.7-1.3 dL / g, an antibacterial rate against Escherichia coli of 30-70%, a tensile strength at break of 40-70 MPa, an oxygen permeability coefficient of 0.02-1.30 bar, a carbon dioxide permeability coefficient of 0.01-0.83 bar, and a water vapor permeability coefficient of 0.0017-3.5×10 -13 g·cm / (cm·s·Pa), which can effectively reduce the rapid consumption of petrochemical resources in the field of polymer materials, alleviate white pollution, and significantly optimize the current commercially available PBAT, PBST and other degradable polyester materials with single functions and limited applications in multiple scenarios. The successful implementation of this invention is of great significance to the high-quality development of green packaging materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments are briefly introduced below.

[0018] The drawings described below only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0019] In the attached figure: Figure 1 This is the molecular structure of the polyequol carbonate-co-butylene carbonate material prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0020] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] The present invention provides the following technical solutions: Example 1

[0022] Germanium oxide (1.05 g, 0.01 mol), stannous octoate (4.05 g, 0.01 mol), tetrabutyl titanate (6.81 g, 0.02 mol), and triphenyl phosphite (3.10 g, 0.01 mol) were mixed evenly and placed in a hydrothermal reactor containing petroleum ether (105 g). The mixture was reacted at 140°C for 18 h. The reaction system was naturally cooled to room temperature and then filtered. The white solid was washed and dried to obtain the new composite catalyst C1. Example 2

[0023] Germanium oxide (1.05 g, 0.01 mol), stannous octoate (8.10 g, 0.02 mol), tetrabutyl titanate (6.81 g, 0.02 mol), and triphenyl phosphite (9.31 g, 0.03 mol) were mixed evenly and placed in a hydrothermal reactor filled with petroleum ether (105 g). After reacting at 150°C for 20 hours, the reaction system was naturally cooled to room temperature and then filtered. After washing and drying, a white solid was obtained, which was the new composite catalyst C2. Example 3

[0024] (1) Esterification reaction: Under nitrogen atmosphere, 484.5 g of equol, 180.2 g of 1,4-butanediol, 450.5 g of dimethyl carbonate, and 2.23 g of C1 composite catalyst were added to the reactor. The temperature in the reactor was raised to 190 °C and kept at this temperature for 5 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 210°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively, and the pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 220°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 5 hours. Then, after water cooling, granulation, and drying, the polyequol carbonate-co-butylene carbonate masterbatch was obtained; wherein: the intrinsic viscosity was 1.24 dL / g, the antibacterial rate against Escherichia coli was 53.2%, the tensile strength at break was 48.9 MPa, the oxygen permeability coefficient was 0.15 bar, the carbon dioxide permeability coefficient was 0.07 bar, and the water vapor permeability coefficient was 1.3×10 -15 g·cm / (cm·s·Pa), and the enzymatic degradation rate was 78.3% after 180 days. Example 4

[0025] (1) Esterification reaction: Under nitrogen atmosphere, 605.7 g of equol, 155.2 g of ethylene glycol, 590.5 g of dimethyl oxalate, and 2.70 g of C2 composite catalyst were added to the reactor. The temperature in the reactor was raised to 180 °C and kept at this temperature for 5 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 210°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively, and the pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 220°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 6 hours. Then, after water cooling, granulation, and drying, the poly(equol oxalate)-co-ethylene glycol oxalate) masterbatch was obtained. Among them, the intrinsic viscosity was 0.91 dL / g, the antibacterial rate against Escherichia coli was 49.1%, the tensile strength at break was 58.0 MPa, the oxygen permeability coefficient was 0.03 bar, the carbon dioxide permeability coefficient was 0.01 bar, and the water vapor permeability coefficient was 0.7×10 -15 g·cm / (cm·s·Pa), and the enzymatic degradation rate was 87.4% after 180 days. Example 5

[0026] (1) Esterification reaction: Under nitrogen atmosphere, 605.7 g of equol, 225.3 g of 1,4-butanediol, 730.7 g of 1,6-hexanediol, and 3.12 g of C1 composite catalyst were added to the reactor. The temperature in the reactor was raised to 220 °C and kept at this temperature for 4 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 230°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively, and the pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 240°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 4 hours. Then, after water cooling, granulation, and drying, the poly(equol adipate)-co-butylene adipate) masterbatch was obtained; wherein: the intrinsic viscosity was 1.18 dL / g, the antibacterial rate against Escherichia coli was 50.5%, the tensile strength at break was 36.7 MPa, the oxygen permeability coefficient was 1.17 bar, the carbon dioxide permeability coefficient was 0.76 bar, and the water vapor permeability coefficient was 1.1×10 -13 g·cm / (cm·s·Pa) and the enzymatic degradation rate was 67.5% after 180 days. Example 6

[0027] (1) Esterification reaction: Under nitrogen atmosphere, 605.7 g of equol, 225.3 g of 1,4-butanediol, 590.5 g of 1,4-butanediol, and 2.84 g of C1 composite catalyst were added to the reactor. The temperature in the reactor was raised to 220 °C and kept at this temperature for 4 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 230°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively, and the pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 240°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 4 hours. Then, after water cooling, granulation, and drying, the poly(equol succinate)-co-butylene succinate) masterbatch was obtained. Among them, the intrinsic viscosity was 1.08 dL / g, the antibacterial rate against Escherichia coli was 49.9%, the tensile strength at break was 39.2 MPa, the oxygen permeability coefficient was 1.02 bar, the carbon dioxide permeability coefficient was 0.55 bar, and the water vapor permeability coefficient was 7×10 -14 g·cm / (cm·s·Pa) and the enzymatic degradation rate was 70.2% after 180 days. Comparative Example 1

[0028] (1) Esterification reaction: Under nitrogen atmosphere, 484.5 g of equol, 180.2 g of 1,4-butanediol, 450.5 g of dimethyl carbonate, and 2.23 g of germanium oxide were added to a reactor. The temperature in the reactor was raised to 190 °C and kept warm for 5 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 210°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively, and the pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 220°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 5 hours. Then, after water cooling, granulation, and drying, the polyequol carbonate-co-butylene carbonate masterbatch was obtained; wherein: the intrinsic viscosity was 0.44 dL / g, the antibacterial rate against Escherichia coli was 43.7%, the tensile strength at break was 18.6 MPa, the oxygen permeability coefficient was 0.19 bar, the carbon dioxide permeability coefficient was 0.22 bar, and the water vapor permeability coefficient was 3.3×10 -14 g·cm / (cm·s·Pa), and the enzymatic degradation rate was 84.6% after 180 days. Comparative Example 2

[0029] (1) Esterification reaction: Under nitrogen atmosphere, 484.5 g of equol, 180.2 g of 1,4-butanediol, 450.5 g of dimethyl carbonate, and 2.23 g of stannous octoate were added to a reactor. The temperature in the reactor was raised to 190 °C and kept warm for 5 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 210°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively, and the pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 220°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 5 hours. Then, after water cooling, granulation, and drying, the polyequol carbonate-co-butylene carbonate masterbatch was obtained; wherein: the intrinsic viscosity was 0.35 dL / g, the antibacterial rate against Escherichia coli was 48.0%, the tensile strength at break was 12.1 MPa, the oxygen permeability coefficient was 0.26 bar, the carbon dioxide permeability coefficient was 0.30 bar, and the water vapor permeability coefficient was 6.9×10 -14 g·cm / (cm·s·Pa), and the enzymatic degradation rate was 87.9% in 180 days. Comparative Example 3

[0030] (1) Esterification reaction: Under nitrogen atmosphere, 484.5 g of equol, 180.2 g of 1,4-butanediol, 450.5 g of dimethyl carbonate, and 2.23 g of tetrabutyl titanate were added to a reactor. The temperature in the reactor was raised to 190 °C and kept warm for 5 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 210°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively, and the pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 220°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 5 hours. Then, after water cooling, granulation, and drying, the polyequol carbonate-co-butylene carbonate masterbatch was obtained; wherein: the intrinsic viscosity was 0.42 dL / g, the antibacterial rate against Escherichia coli was 32.1%, the tensile strength at break was 20.2 MPa, the oxygen permeability coefficient was 0.11 bar, the carbon dioxide permeability coefficient was 0.27 bar, and the water vapor permeability coefficient was 1.7×10 -14 g·cm / (cm·s·Pa), and the enzymatic degradation rate was 85.2% after 180 days. Comparative Example 4

[0031] (1) Esterification reaction: Under nitrogen atmosphere, 484.5 g of equol, 180.2 g of 1,4-butanediol, 450.5 g of dimethyl carbonate, and 2.23 g of triphenyl phosphite were added to a reactor. The temperature in the reactor was raised to 190 °C and kept warm for 5 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 210°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively, and the pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 220°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 5 hours. Then, after water cooling, granulation, and drying, the polyequol carbonate-co-butylene carbonate masterbatch was obtained; wherein: the intrinsic viscosity was 0.17 dL / g, the antibacterial rate against Escherichia coli was 17.7%, the tensile strength at break was 18.3 MPa, the oxygen permeability coefficient was 2.8 bar, the carbon dioxide permeability coefficient was 3.94 bar, and the water vapor permeability coefficient was 5.6×10 -12 g·cm / (cm·s·Pa), and the enzymatic degradation rate was 93.1% in 180 days. Comparative Example 5

[0032] (1) Esterification reaction: Under nitrogen atmosphere, 415.3 g of terephthalic acid, 450.6 g of 1,4-butanediol, 365.4 g of adipic acid, and 2.46 g of C1 composite catalyst were added to the reactor. The temperature in the reactor was raised to 230 °C and kept warm for 4 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 235°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively, and the pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 240°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 3 hours. Then, after water cooling, granulation, and drying, polybutylene terephthalate-co-butylene adipate masterbatch was obtained; wherein: the intrinsic viscosity was 1.27 dL / g, the antibacterial rate against Escherichia coli was 5.1%, the tensile strength at break was 25.6 MPa, the oxygen permeability coefficient was 35.1 bar, the carbon dioxide permeability coefficient was 280.4 bar, and the water vapor permeability coefficient was 5.8×10 -13 g·cm / (cm·s·Pa), and the enzymatic degradation rate was 92.7% after 180 days. Comparative Example 6

[0033] (1) Esterification reaction: Under nitrogen atmosphere, 415.3 g of terephthalic acid, 450.6 g of 1,4-butanediol, 295.3 g of succinic acid, and 2.32 g of C1 composite catalyst were added to the reactor. The temperature in the reactor was raised to 230 °C and kept warm for 4 h. The esterification reaction was completed. (2) Pre-polycondensation reaction: turn off the esterification unit, turn on the polycondensation unit, raise the temperature in the kettle to 235°C, and slowly reduce the vacuum degree. React at 8000Pa, 5000Pa, and 1000Pa for 20 minutes respectively. The pre-polycondensation reaction is completed; (3) Final polycondensation reaction: The temperature in the autoclave was raised to 240°C, the air inlet valve was completely closed, the vacuum degree of the reaction system was reduced to below 50 Pa, and the above conditions were maintained for 3 hours. Then, after water cooling, granulation, and drying, polybutylene terephthalate-co-butylene succinate masterbatch was obtained; wherein: the intrinsic viscosity was 1.12 dL / g, the antibacterial rate against Escherichia coli was 6.3%, the tensile strength at break was 28.3 MPa, the oxygen permeability coefficient was 29.4 bar, the carbon dioxide permeability coefficient was 320.1 bar, and the water vapor permeability coefficient was 2.7×10 -13 g·cm / (cm·s·Pa), and the enzymatic degradation rate was 88.0% after 180 days.

[0034] The intrinsic viscosity test method in the examples is as follows: according to 5.1.1 of GB / T 14190-2008; Intrinsic viscosity: Dissolve 0.2g of product in 20ml of a 1:1 phenol-1,1,2,2-tetrachloroethane mixed solution and measure the intrinsic viscosity using the one-point method in a 25℃ water bath. The formula for calculating the intrinsic viscosity is: ; ; ; in: : relative viscosity, : Increased specific viscosity, : Solvent elution time, : polymer solution outflow time, : polymer solution concentration; The test method for the antibacterial rate in the embodiment is characterized according to GB / T 31402-2015; The test method of tensile strength at break in the embodiment is characterized according to ISO 527-2019; The test methods for oxygen and carbon dioxide permeability coefficients in the examples are characterized according to GB / T 1038; The test method of water vapor transmission coefficient in the embodiment is characterized according to GB / T 1037; The test method for the 180-day degradation rate in the embodiment is as follows: a 1 g equol-based polyester material with a thickness of 0.1 mm is placed in a lipase degradation solution with a concentration of 0.1 mg / mL. Subsequently, the enzyme degradation solution containing the sample is placed in a constant temperature water shaker at 65°C. After 180 days of degradation, the sample is removed, washed with deionized water, and dried in a vacuum oven at 50°C until the mass of the enzyme-degraded sample no longer changes. The sample is then removed and the remaining mass is weighed, and the degradation rate is calculated based on this: Degradation rate = (mass of sample before degradation - mass of sample after degradation) × 100% / mass of sample before degradation.

[0035] Table 1 Summary of properties of equol-based biodegradable polyesters Product Name catalyst Intrinsic viscosity (dL / g) Antibacterial rate (%) Tensile strength at break (MPa) Oxygen permeability coefficient (bar) Carbon dioxide permeability coefficient (bar) Water vapor permeability coefficient (g·cm / (cm·s·Pa) Degradation rate (%) Example 3 Polyequol carbonate-co-butylene carbonate <![CDATA[C1]]> 1.24 53.2 82.7 0.15 0.07 <![CDATA[1.3×10 -15 ]]> 78.3 Example 4 Polyequol oxalate-co-ethylene glycol oxalate <![CDATA[C2]]> 0.91 49.1 58.0 0.03 0.01 <![CDATA[0.7×10 -15 ]]> 87.4 Example 5 Poly(equol adipate)-co-butylene adipate <![CDATA[C1]]> 1.18 50.5 36.7 1.17 0.76 <![CDATA[1.1×10 -13 ]]> 67.5 Example 6 Polyequol succinate-co-butylene succinate <![CDATA[C1]]> 1.08 49.9 39.2 1.02 0.55 <![CDATA[7.0×10 -14 ]]> 70.2 Comparative Example 1 Polyequol carbonate-co-butylene carbonate Germanium oxide 0.44 43.7 18.6 0.19 0.22 <![CDATA[3.3×10 -14 ]]> 84.6 Comparative Example 2 Polyequol carbonate-co-butylene carbonate Stannous octoate 0.35 48.0 12.1 0.26 0.30 <![CDATA[6.9×10 -14 ]]> 87.9 Comparative Example 3 Polyequol carbonate-co-butylene carbonate Tetrabutyl titanate 0.42 32.1 20.2 0.11 0.27 <![CDATA[1.7×10 -14 ]]> 85.2 As shown in Table 1, when Example 3 is compared with Comparative Examples 1-4, the intrinsic viscosity of the biomass-based equol-based degradable polyester material with combined antibacterial, high-strength, and high-barrier properties is significantly increased when the novel composite catalyst is used to prepare the material, whereas the catalytic effect of the non-composite catalyst is relatively poor. As shown in Table 1, when Example 5 is compared with Comparative Example 5, and Example 6 is compared with Comparative Example 6, the mechanical strength and barrier properties of currently available PBAT and PBST are significantly improved when equol is used to prepare the degradable polyester, thereby overcoming the problems of low mechanical strength and poor barrier properties of currently available degradable polyesters when used in packaging materials.

[0036] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a multifunctional biomass equol-based packaging material, characterized in that: The following steps are involved: Step 1: preparing a composite catalyst for preparing a multifunctional biomass equol polyester material, wherein the raw materials for preparing the composite catalyst include germanium oxide, stannous octoate, tetrabutyl titanate and triphenyl phosphite; the molar ratio of the germanium oxide to the stannous octoate is 1:1-1:10; the molar ratio of the germanium oxide to the tetrabutyl titanate is 1:1-1:15; and the molar ratio of the germanium oxide to the triphenyl phosphite is 1:0.1-0.5; Step 2: The composite catalyst is prepared by the following method: i) mixing germanium oxide, stannous octoate, tetrabutyl titanate and triphenyl phosphite, and adding them together to petroleum ether, wherein the mass ratio of the germanium oxide to the petroleum ether is 1:50-1:100, and reacting at 120-180° C. for 10-24 hours; ii) Cooling the reactants to room temperature and filtering them, washing and drying them to obtain a white solid, which is the composite catalyst; Step 3: Add equol, linear aliphatic dibasic acid, linear aliphatic diester, and linear aliphatic diol into a reactor in proportion, and prepare a degradable equol-based polyester material through esterification, pre-condensation, and final polycondensation under the action of the composite catalyst.

2. The method for preparing a multifunctional biomass equol-based packaging material according to claim 1, characterized in that: The reaction temperature of step 2 is 120-150°C, and the reaction time is 16-20 hours.

3. The method for preparing a multifunctional biomass equol-based packaging material according to claim 1, characterized in that: In step 2, the molar ratio of germanium oxide to stannous octoate is 1:1-1:5; the molar ratio of germanium oxide to tetrabutyl titanate is 1:1-1:10; the molar ratio of germanium oxide to triphenyl phosphite is 1:0.1-0.3; and the mass ratio of germanium oxide to petroleum ether is 1:80-1:

100.

4. The method for preparing a multifunctional biomass equol-based packaging material according to claim 1, characterized in that: The method for preparing the degradable equol-based polyester material in step 3 specifically comprises the following steps: (1) Esterification reaction: under the protection of inert gas, equol, linear aliphatic dibasic acid, linear aliphatic dibasic ester, linear aliphatic diol and composite catalyst are added to the reactor, the reaction temperature is controlled within the range of 180-220 ° C, and the reaction time is 3-8 h; (2) Pre-condensation reaction: raise the temperature in the autoclave to 220-250°C, gradually reduce the vacuum degree to below 1000 Pa, and the reaction time should be no less than 1 hour; (3) Final polycondensation reaction: the temperature in the autoclave is raised to 220-260°C, the vacuum degree is gradually reduced to below 50 Pa, and the reaction time is 2-6 hours. After the final polycondensation is completed, the biodegradable equol polyester material is obtained through water cooling, granulation, and drying.

5. The method for preparing a multifunctional biomass equol-based packaging material according to claim 4, characterized in that: The linear aliphatic dibasic acid includes one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid; the linear aliphatic dibasic ester includes one or more of dimethyl carbonate, dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, dimethyl pimelic acid, dimethyl suberate, dimethyl azelaic acid, and dimethyl sebacate; the linear aliphatic diol includes one or more of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol.

6. The method for preparing a multifunctional biomass equol-based packaging material according to claim 4, characterized in that: The amount of the composite catalyst used is 0.01-0.5% of the total weight of the reaction system.

7. The method for preparing a multifunctional biomass equol-based packaging material according to claim 4, characterized in that: In step (1), after the feeding is completed, the air inside the reactor is evacuated by inert gas replacement method. The esterification temperature is preferably 190-200°C, and the reaction time is preferably 4-6 hours.

8. The method for preparing a multifunctional biomass equol-based packaging material according to claim 4, characterized in that: In step (2), the pre-condensation temperature is preferably 220-240° C., and the pre-condensation vacuum is respectively 8000 Pa, 5000 Pa, and 1000 Pa for 20 min.

9. The method for preparing a multifunctional biomass equol-based packaging material according to claim 4, characterized in that: In step (3), the final polycondensation temperature is preferably 230-250° C., and the reaction time is preferably 3-5 h.

10. The method for preparing a multifunctional biomass equol-based packaging material according to claim 4, characterized in that: The specific steps after the final polycondensation in step (3) are as follows: using an inert gas to increase the pressure in the reaction system to 0.1-0.3 MPa, cutting the product melt into particles after water cooling, and then placing the particles in a vacuum oven at 80°C and drying for 4 hours to obtain polyethylene terephthalate-co-terephthalate.

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