A polyglycolic acid biodegradable block copolymer and copolymer film thereof, and a method of manufacturing and use thereof

Abstract

The present application relates to a kind of polyglycolic acid biodegradable block copolyester film, mainly solve the existing polyglycolic acid material poor mechanical properties in prior art and cannot meet the application problem.The polyglycolic acid block copolyester film includes: 70~90 parts of polyglycolic acid and derivative block by mass percentage, 10~30 parts of polyethylene glycol block.In the present application, the required amount of glycolic acid and derivative, polyethylene glycol, reaction extrusion in double screw extruder, granulation drying, extrusion blowing film or casting is obtained after the described polyglycolic acid biodegradable block copolyester film, the obtained film material has excellent bonding performance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a biodegradable block copolyester of polyglycolic acid and its copolyester film, as well as their preparation method and application. Background Technology

[0002] Polyglycollide (PGA), also known as polyhydroxyacetic acid or polyglycolic acid, is a linear aliphatic polyester with the simplest chemical structure. It is a highly biocompatible and biodegradable polymer widely used in surgical sutures, orthopedic fixation, tissue repair materials, and controlled drug release systems. However, its high melting point makes it difficult to mold and process.

[0003] Polyethylene glycol (PEG), also known as ethylene glycol polyoxyethylene ether or polyethylene oxide, typically has hydroxyl or methoxy groups at its end. Its molecular weight ranges from 200 to 20,000. It possesses good water solubility, biocompatibility, and flexibility, and is non-toxic and non-irritating, making it widely used in various pharmaceutical preparations. Its properties vary depending on its relative molecular weight, ranging from a colorless, odorless, viscous liquid to a waxy solid, and it has a relatively low glass transition temperature and melting point.

[0004] Traditional methods for chemically modifying the mechanical properties of PGA include synthesizing random copolymers of glycolide and lactide or modifying them using polymers containing hydroxyl groups. These methods involve reactor polymerization, which requires harsh reaction conditions, long reaction times, and makes it difficult to control the polymer structure.

[0005] Because PGA polymers possess high barrier properties and biodegradability, they can be used in the preparation of multilayer co-extruded films. However, in practical applications, due to the high crystallinity and extremely fast crystallization rate of PGA itself, its adhesion to other multilayer films is poor, making it difficult to use as a single-layer or multilayer film. Summary of the Invention

[0006] This invention provides a polyglycolic acid biodegradable block copolyester film with excellent adhesion properties. By reacting and extruding copolymerizing glycolic acid and / or its derivatives under the action of polyethylene glycol, a polyglycolic acid biodegradable block copolyester containing flexible segments of polyethylene glycol is obtained. Other flexible block copolymer components with lower melting points are introduced into the PGA segments, so that the copolyester and its film material can partially melt when the low melting point of the flexible blocks is reached, thereby exhibiting excellent adhesion properties.

[0007] One objective of this invention is to provide a biodegradable block copolyester of polyglycolic acid, wherein, by weight, the block copolyester comprises:

[0008] (1) 70-90 parts of polyglycolic acid homopolymer blocks;

[0009] (2) 10 to 30 parts of polyethylene glycol blocks.

[0010] In the above-mentioned polyglycolic acid biodegradable block copolyester:

[0011] The block copolyester structure is PEG-b-PGA or PGA-b-PEG-b-PGA, and the block copolymer contains two glass transition temperatures and at least two melting points;

[0012] The monomers of the polyglycolic acid homopolymer are selected from at least one of glycolic acid, glycolide, methyl glycolate and their anhydrides, preferably glycolide;

[0013] The polyethylene glycol is a polymer formed by ring-opening polymerization of ethylene oxide with water or alcohol;

[0014] In the block copolyester, the number average molecular weight of the polyglycolic acid homopolymer blocks is 1000-100000 g / mol, preferably 2000-80000 g / mol; the number average molecular weight of the polyethylene glycol blocks is 200-50000 g / mol, preferably 1000-20000 g / mol.

[0015] The second objective of this invention is to provide a method for preparing the above-mentioned polyglycolic acid biodegradable block copolyester, which includes mixing components including glycolic acid and / or its derivatives, polyethylene glycol, and performing a melt extrusion reaction to obtain the polyglycolic acid biodegradable block copolyester. The melt extrusion reaction is preferably carried out by a twin-screw extruder.

[0016] Specifically, the glycolic acid and / or its derivatives are selected from at least one of glycolic acid, glycolide, methyl glycolate and their anhydrides, preferably glycolide;

[0017] The polyethylene glycol has a number-average molecular weight of 200–50,000 g / mol, preferably 1,000–20,000 g / mol;

[0018] The reaction also includes a metal compound catalyst, which is a salt compound corresponding to at least one of group IIA-VA metal elements and transition metal elements, preferably selected from at least one of stannous octoate, stannous chloride, aluminum isopropoxide, bismuth acetate, n-butyl titanate, and tetrabutyl stannate, more preferably selected from stannous chloride; the amount of the metal compound catalyst added is 0.01 to 0.5 parts, preferably 0.03 to 0.3 parts, based on 100 parts by weight of glycolic acid and / or its derivatives;

[0019] The extrusion reaction temperature is 150–250℃, preferably 160–230℃; the extrusion reaction time is 3–20 min, preferably 5–10 min; and the screw extruder speed is 5–150 rpm, preferably 20–80 rpm. This invention uses a twin-screw extruder for continuous polymerization, which saves time, simplifies the process, and increases production efficiency compared to the batch reactor polymerization in the prior art.

[0020] The third objective of this invention is to provide a polyglycolic acid biodegradable block copolyester film, which is prepared from the above-mentioned polyglycolic acid biodegradable block copolyester or from the polyglycolic acid biodegradable block copolyester obtained by the above-mentioned preparation method.

[0021] A fourth objective of this invention is to provide a method for preparing the aforementioned polyglycolic acid biodegradable block copolyester film, comprising extruding a component including the aforementioned polyglycolic acid biodegradable block copolyester through an extruder for blown film production or casting, thereby obtaining the biodegradable block copolyester film. Preferably, the blown film production or casting can be performed using commonly used extrusion equipment in the art, such as a single-screw extruder, and the process conditions can be set to achieve the purpose of casting into a film using common process conditions; preferably, the blown film production or casting temperature is 180–230°C.

[0022] The hot-pressing temperature of the biodegradable block copolyester film obtained by the above preparation method is 160-180℃, preferably 165-175℃.

[0023] The fifth objective of this invention is to use the above-mentioned biodegradable polyglycolic acid block copolyester film or the biodegradable polyglycolic acid block copolyester film obtained according to the above preparation method in biodegradable film products.

[0024] In this invention, glycolic acid and its derivatives are reactively extruded and copolymerized in an extruder under the initiation of polyethylene glycol (PEG). The reaction takes only 3-20 minutes. The active hydroxyl groups at the ends of the PEG end groups, catalyzed by a metal compound catalyst, initiate the condensation or ring-opening polymerization of glycolic acid and its derivatives, resulting in a biodegradable block copolyester containing flexible PEG segments, thus improving the adhesion properties of PGA. The flexible PEG segments in the chain provide a lower melting point, achieving a melt-bonding effect near this melting point range. This overcomes the shortcomings of high melting point and high crystallization rate of polyglycolic acid polymers, which hinder bonding, resulting in a high-adhesion-performance biodegradable block copolyester film made from polyglycolic acid.

[0025] Compared with the prior art, the present invention has superior effects:

[0026] 1. The addition of flexible block copolymer components to the thin film material provided by the present invention can effectively improve the adhesion performance of the thin film material;

[0027] 2. The preparation method provided by this invention has a simple and efficient production process and broad application prospects. Attached Figure Description

[0028] Figure 1 The data are DSC heating curves for Examples 1 to 3, where curves a to c are Example 1, Example 2, and Example 3, respectively.

[0029] Figure 2 The data are DSC heating curves of raw materials PEG2000 and PGA, where a represents PGA and b represents PEG2000.

[0030] Figure 3 The images show the infrared spectra of block polymer Example 2 and PGA homopolymer, where a is the PGA homopolymer and b is block polymer Example 2.

[0031] Figure 4 The image shows the proton NMR spectrum of the block polymer in Example 2.

[0032] Figure 5 This is the proton NMR spectrum of PGA homopolymer.

[0033] Figure 6 The rotational rheological viscosity results are for block polymer Example 2 and PGA homopolymer, where curve a represents PGA homopolymer and curve b represents block polymer Example 2.

[0034] Figure 7 The DSC heating curve data of the polymers were obtained for comparative examples 1 to 4, where curves a to d are comparative examples 1, 2, 3 and 4 respectively. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0036] The testing instruments and conditions used in this embodiment are as follows:

[0037] Melt flow index (MFR) determination method: According to ISO 1133 standard, the Instron CEAST MF20 melt flow indexer was used for determination. The barrel temperature was 230℃, the weight load was 1.05kg, the die diameter was 2.095mm, the preheating time was 30s, the sample was automatically cut at set time intervals, and the average value of 5 samples was taken. The result was expressed as grams per 10 minutes (g / 10min).

[0038] Thermal performance analysis (DSC): Tests were performed on a Discovery series differential scanning calorimeter (DSC) manufactured by TA Instruments, using TA Instruments Trios version 3.1.5 software. This DSC instrument is equipped with a TARefrigerated Cooling System 90 mechanical refrigeration accessory. The test atmosphere was nitrogen at a flow rate of 50 mL / min, and the required sample volume was 5–10 mg. The test procedure was as follows: the temperature was first stabilized at 40℃, then increased to 250℃ at a rate of 10℃ / min and held at that temperature for 1 min to remove thermal history. The temperature was then decreased to -60℃ at a rate of 10℃ / min, followed by a reheat to 250℃ at a rate of 10℃ / min. The cooling process and the second heating process were recorded to study the thermal properties of the sample. The glass transition (Tg) of the sample can be directly obtained from the DSC test software. g Melting temperature (T) m Information such as ""

[0039] FTIR spectroscopy: The synthesized biodegradable polyglycolic acid block copolyester was pulverized using a pulverizer. A certain amount of powder was weighed and added to dried potassium bromide (KBr) powder for thorough grinding, followed by tableting (sample to potassium bromide mass ratio of 1:100). The tablets were then scanned using a FTIR spectrometer with a scanning range of 600–4000 cm⁻¹. -1 The number of scans was 16.

[0040] 1H NMR spectrum ( 1 H-NMR: The composition and structure of the polymer were analyzed using a 500MHz superconducting Fourier transform nuclear magnetic resonance spectrometer from Bruker, Germany. Deuterated dimethyl sulfoxide (DMSO-d6) was used as the solvent and tetramethylsilane as the internal standard. 5-10 mg of the sample was dissolved in 0.6 ml of solvent at 150 °C and liquid NMR was performed.

[0041] Mechanical property testing: The test was conducted on a universal testing instrument (model 3344) manufactured by Instron Corporation in the United States. The test temperature was 20℃, the test humidity was 65%, the tensile rate was 5mm / min, and the effective length of the sample was 30mm. The tensile stress and elongation at break of 5 samples from the same batch were recorded and the average value was taken.

[0042] Melt viscosity testing: The test was conducted on an advanced rotational rheometer (model MCR302) manufactured by Anton Paar GmbH, Austria, at a temperature of 230°C, with a shear rate range of 1 to 100 s. -1 Record parameters such as shear strength, melt viscosity, and torque of the sample at a certain shear rate.

[0043] Adhesion performance test: An INSTRON 3344 film testing machine was used. The film was cut into a 50mm x 6mm rectangle. During testing, the initial clamp spacing was 30mm, and the tensile rate was 300mm / min. Using the heat-sealed area as the center, the upper film was peeled to the same position, then opened 180°. The two ends of the sample were clamped onto the two clamps of the testing machine, with the lower ends of the sample extending the same length. Each sample was tested 5 times, and the average value was recorded. The maximum load at which the sample broke was read.

[0044]

Examples 1-3

[0045] The glycolide (GA) monomer used in this invention was produced by Jinan Daigang Biotechnology Co., Ltd., China. The polyethylene glycol (PEG2000, number-average molecular weight 2000 g / mol) monomer was provided by China National Pharmaceutical Group Corporation. Stannous chloride (SnCl2) was provided by Shanghai Maclean Reagent Co., Ltd.

[0046] Elygorithm powder was first dried in a vacuum oven at 60°C for 5 hours to remove moisture. Then, it was mixed in a mixer at specific mass ratios of GA / PEG: 90 / 10 (Example 1), 80 / 20 (Example 2), and 70 / 30 (Example 3), with a mixing time of 10 minutes. Subsequently, 0.03 parts by mass of Sn(Cl)₂ was added to the mixed powder and mixed thoroughly. Granulation was performed using a Eurolab 16 co-rotating twin-screw extruder (screw diameter 16 mm, L / D ratio L / D = 40) manufactured by Thermo Fisher Scientific. This extruder has 11 sections from the feed port to the die, numbered 1-11, where section 1 only serves as the feed port and does not provide heating. Because the properties of the product from this reactive extrusion vary considerably with the formulation, the temperature of each section of the extruder was adjusted accordingly, as shown in the table below. The extrusion reaction time was approximately 5 minutes. The screw speed was set at 40 rpm. During stable operation, the maximum torque was 20%-30%. The extruder is equipped with a circular die with a diameter of 3 mm. After the sample is extruded from the die and cooled by air, it is cut into cylindrical particles with a diameter of 3 mm by a pelletizer. The particles are then dried in a vacuum oven at 30°C for 5 hours and then packaged for later use.

[0047] Table 1. Temperatures of each heating section in the GA / PEG reactive extruder

[0048]

[0049] Table 2. Number average molecular weight of copolyester PEG and PGA segments in Examples 1-3

[0050] Sample Name <![CDATA[M n (PEG)]]> <![CDATA[M n (PGA)]]> PEG content (%) Example 1 2000 17000 10.5 Example 2 2000 7500 21.1 Example 3 2000 4500 30.8

[0051] [Example 4] DSC test of polyglycolic acid biodegradable block copolyester

[0052] All three types of particles, as well as the homopolymers of GA (PGA and polyethylene glycol PEG2000, molecular weight 2000 g / mol), were subjected to differential scanning calorimetry (DSC) tests according to the steps described above, resulting in the second heating curve. The melting temperature (T) was then directly obtained from these curves using specialized software. m ), glass transition (T) g Information such as crystallinity was collected, and the crystallinity was calculated using the crystallinity calculation formula. The values ​​are listed in Table 3.

[0053] Table 3. Thermal properties of copolyesters and PGA / PEG from Examples 1-3

[0054] Sample Name <![CDATA[T g1 (℃)]]> <![CDATA[T g2 (℃)]]> <![CDATA[T m(PGA) (℃)]]> PGA - 47.5 225.4 Example 1 -5.2 47.7 209.8 Example 2 -6.8 46.9 207.4 Example 3 -23.2 45.7 194.9 PEG2000 -65.2 - 36.5

[0055] from Figure 1 As shown in Table 3, after polymerization using PEG2000 as an initiator, two glass transition temperatures appeared in the thermodynamic tests: one in the range of -30 to 0℃, belonging to the PEG segment; and the other in the range of 45 to 50℃, belonging to the PGA segment. During the heating process, multiple melting peaks appeared, with the largest melting peak near 200℃ belonging to PGA, while the other melting peaks should be those of segments appearing in the block structure. With the increase of PEG2000 content, the glass transition temperature and melting point of the PGA segment gradually decreased slightly, while the glass transition temperature of the PEG segment decreased to some extent. For example, in the 30% PEG sample, two glass transition temperatures appeared, at -23.2℃ and 45.7℃. The glass transition temperature of the PGA segment decreased from 47.5℃ to 45.7℃; the melting point decreased from 225.4℃ to 194.9℃, and two melting peaks appeared at 139.8℃ and 148.8℃. After adding PEG for initiation, the melting point of PGA decreases due to the interaction between PEG and PGA segments, and the glass transition temperatures of PEG and PGA move closer to the middle. The special structure of the block also produces two special melting peaks, but the melting peak of PEG2000 initiator is not found.

[0056] [Example 5] Melt Flow Index Test of Biodegradable Polyglycolic Acid Block Copolyester

[0057] The particles from Examples 1 to 3, as well as the PGA homopolymer, were tested for melt index using an Instron CEAST MF20 melt indexer. Due to the high temperature sensitivity of PGA block polymer materials, the test conditions were changed accordingly. The test conditions and results are shown in Table 4.

[0058] Table 4. Melt index of each material under suitable test conditions

[0059] Sample Name Test conditions Melt index (g / 10min) PGA 230℃, 1.05kg 14.01 Example 1 210℃, 1.05kg 24.43 Example 2 210℃, 1.05kg 29.06 Example 3 200℃, 1.05kg 34.72 PEG2000 50℃, 1.05kg 10.54

[0060] As shown in Table 4, the flow properties of the PGA block polymer modified material gradually increase with the increase of PEG content. Specifically, when the temperature is about 5-10°C above the melting point, the melt index reaches 20 g / 10 min. For example, when the amount of PEG added is 30 parts (Example 3), the melt index is 34.72 g / 10 min at 200°C and 1.05 kg.

[0061] [Example 6] Infrared spectroscopy of biodegradable polyglycolic acid block copolyester

[0062] The infrared spectra of Example 2 and the PGA homopolymer were tested. Figure 3 It can be clearly observed that 1736 cm⁻¹ appears in the infrared spectra of both. -1 The absorption peak at 1413 cm⁻¹ is attributed to the absorption vibration peak of the carbonyl C=O group. -1 The absorption vibration peak of methylene-CH2- at 1071 cm⁻¹ -1 The absorption vibration peaks at -COC- were observed; these absorption peaks are characteristic peaks of pure polyethylene glycolide. However, the infrared spectrum of Example 2 showed a peak at 1214 cm⁻¹, which is only present in PEG blocks. -1 The characteristic absorption peak of -OCH2CH2- at that location.

[0063] [Example 7] Nuclear Magnetic Resonance Testing of Biodegradable Polyglycolic Acid Block Copolyester

[0064] The PGA homopolymer (A) and Example 2 (B) were subjected to 1H NMR spectroscopy tests. The results were obtained by analyzing the 1H NMR spectra of both samples. Figure 4 , Figure 5Comparing the two spectra, the signal peak around 5.0 ppm (a) that appears in both spectra belongs to the PGA segment; the signal peaks at 3.3 ppm and 2.5 ppm are characteristic peaks of the DMSO solvent. The signal at 4.1 ppm (b) that appears in the 1H NMR spectrum of the block copolymer should be attributed to the characteristic peak of the H atom at the junction of PEG and PGA, while the signal peak at 3.5 ppm (c) is the H atom in the PEG segment, confirming the presence of PEG and PGA segments in the polymer.

[0065] [Example 8] Mechanical property testing of biodegradable polyglycolic acid block copolyester

[0066] Mechanical properties of PGA homopolymer (A) and Examples 1-3 were tested. By comparing the elongation at break and tensile strength of the two, under the condition that the molecular weight does not change much, the tensile strength decreases with the increase of PEG segment content, while the elongation at break increases. This confirms that the addition of PEG segment can improve the tensile properties of PGA polymer and improve its toughness to a certain extent.

[0067] Table 5. Tensile property tests of copolyesters and pure PGA in Examples 1-3

[0068] Sample Name Tensile strength (MPa) Elongation at break (%) PGA 59.96 3.29 Example 1 42.61 6.28 Example 2 35.27 8.36 Example 3 28.62 11.38

[0069] [Example 9] Melt viscosity test of biodegradable polyglycolic acid block copolyester

[0070] Melt viscosity tests were performed on PGA homopolymer (A) and Example 2 (B) respectively, and the melt viscosity of the two was compared. Figure 6 It can be observed that under the same test conditions, when the shear rate reaches 100 s... -1 At that time, the melt strength of pure PGA was approximately 43 Pa*S, while the melt viscosity of Example 2 decreased to 3.8 Pa*S, confirming that the melt viscosity decreased significantly with the addition of PEG segments.

[0071] [Example 10] Preparation and Adhesion Performance Testing of Biodegradable Polyglycolic Acid Block Copolyester Film

[0072] The polyglycolic acid biodegradable block copolyesters obtained in Examples 1-3 and HAAKE manufactured by ThermoFisher Scientific Inc. in the United States using pure PGA were combined. TM Cast film production was performed on a Rheomex OS single-screw extruder with a screw speed of 50 rpm and barrel temperatures of 180℃, 230℃, 230℃, and 220℃.

[0073] After preparing films from PGA and the materials of Examples 1-3, the two films were hot-pressed at 160°C for approximately 3 minutes, and their adhesion properties were tested. The results are shown in Table 6 below. As can be seen from the data in Table 6, even at a relatively high hot-pressing temperature (230°C), the maximum breaking load of the PGA homopolymer is 0, indicating no adhesion properties. In contrast, the films from Examples 1-3, even at a lower hot-pressing temperature (165°C), formed a bonded multilayer material with a maximum breaking load of 0.05-0.06 N, thus solving the problem of PGA homopolymer's inability to be heat-sealed. The films obtained in Examples 1-3 possess heat-sealable properties, which is crucial for the production of packaging bags and other products.

[0074] Table 6. Adhesion performance test of thin film materials

[0075] Sample Name Hot pressing temperature (°C) Maximum breaking load (N) PGA 230 0.00 Example 1 165 0.05 Example 2 165 0.06 Example 3 165 0.05

[0076] Comparative Examples 1-4

[0077] The glycolide (GA) monomer used in this invention was produced by Jinan Daigang Biotechnology Co., Ltd., China. The polyethylene glycol (PEG) monomers (molecular weight 600, 1000) were produced by China National Pharmaceutical Group Corporation. The stannous chloride (SnCl2) was produced by Shanghai Maclean's Reagent Co., Ltd.

[0078] Glycolide powder was first dried in a vacuum oven at 60°C for 5 hours to remove moisture. Then, 0.1% and 0.2% PEG monomers were added to the GA powder and mixed in a mixer for 10 minutes. Subsequently, 0.03 parts by weight of Sn(Cl)2 were added to the mixed powder and mixed evenly. The formulations for Comparative Example 1 were 0.1% PEG600, Comparative Example 2 was 0.1% PEG1000, Comparative Example 3 was 0.2% PEG600, and Comparative Example 4 was 0.2% PEG1000. Granulation was performed using a Eurolab 16 co-rotating twin-screw extruder (screw diameter 16 mm, L / D ratio L / D = 40) manufactured by Thermo Fisher Scientific. The extruder has 11 sections from the feed port to the die, numbered 1-11. Section 1 only serves as the feeding section and does not provide heating. The temperatures of each section of the extruder were the same as in Example 1 in Table 1. The extrusion reaction time was approximately 5 minutes, and the screw speed was set at 40 rpm. During stable operation, the maximum torque is 20%-30%. The extruder is equipped with a 3mm diameter circular die. After extrusion and air cooling, the sample is cut into 3mm diameter cylindrical particles by a pelletizer. Then, it is dried in a 30℃ vacuum oven for 5 hours before being packaged for later use.

[0079] Comparative Examples 1, 2, 3, and 4 were subjected to differential scanning calorimetry (DSC) tests according to the steps described above, resulting in the second heating curves. Figure 7 The melting temperature (T) can be obtained directly from it using specialized software. m ), glass transition (T) g Information such as )

[0080] With the addition of very small amounts of PEG, the thermodynamic properties of the PGA block polymer did not change significantly, and parameters such as melting point remained largely unchanged. Due to the low content of the PEG polymer, the PEG segments in the polymer after GA monomer polymerization were also low, and the PEG segments could not provide effective performance improvement.

[0081] Table 7. Thermal properties and melt flow index of the polymers obtained in Comparative Examples 1–4

[0082] Sample Name Tg (°C) <![CDATA[Tm (PGA) (℃)]]> Melt index (g / 10min) Comparative Example 1 47.5 223.1 15.24 Comparative Example 2 47.7 222.8 14.13 Comparative Example 3 46.9 223.4 16.35 Comparative Example 4 45.7 221.5 14.97

[0083] The particles obtained from Comparative Examples 1 to 4 were cast into films on a single-screw extruder at a screw speed of 50 rpm and barrel temperatures of 200℃, 230℃, 230℃, and 220℃, respectively.

[0084] The film adhesion ability was tested to be similar to that of pure PGA. It was difficult to bond the two films together by hot pressing. Therefore, the comparative examples 1 to 4 with low PEG content had poor adhesion performance.

[0085] Comparative Example 5

[0086] The glycolide (GA) monomer used in this invention was produced by Jinan Daigang Biotechnology Co., Ltd., China. Polyethylene oxide (PEO) (molecular weight 100,000) was produced by Dow Chemical Company, USA. Stannous chloride (SnCl2) was produced by Shanghai Maclean Reagent Co., Ltd.

[0087] Ethylene lactide powder was first dried in a vacuum oven at 60°C for 5 hours to remove moisture. Then, 20% by weight of PEO polymer was added to GA powder and mixed in a mixer for 10 minutes. Subsequently, 0.03 parts by weight of Sn(Cl)2 were added to the mixed powder and mixed evenly. Granulation was performed using a Eurolab 16 co-rotating twin-screw extruder (screw diameter 16 mm, L / D ratio L / D = 40) manufactured by Thermo Fisher Scientific, USA. This extruder has 11 sections from the feed port to the die, numbered 1-11, where section 1 only serves as the feeding section and does not provide heating. The temperatures of each section of the extruder were the same as in Example 1 in Table 1. The extrusion reaction time was approximately 5 minutes, and the screw speed was set at 40 rpm.

[0088] The obtained product was subjected to performance testing: T mThe melting point was 192.4℃, the melt index at 195℃ and 1.05kg was 42.15g / 10min, and the melt viscosity measured by rotational rheometer was within 100s. -1 The shear rate is 0.2 Pa*S. Due to the low melt strength, it is difficult to injection mold into a sample.

[0089] Comparative Example 6

[0090] The glycolide (GA) monomer used in this invention was produced by Jinan Daigang Biotechnology Co., Ltd., China. The lactide (LA) monomer was produced by Tokyo Chemical Industry Co., Ltd. The polyethylene glycol (PEG2000, number average molecular weight 2000 g / mol) monomer was produced by China National Pharmaceutical Group Corporation. The stannous chloride (SnCl2) was produced by Shanghai Maclean Reagent Co., Ltd.

[0091] Ethylene lactide and lactide powders were dried in a vacuum oven at 60°C for 5 hours to remove moisture. Then, they were mixed in a mixer at a specific mass ratio of GA / LA / PEG of 75 / 15 / 10 for 10 minutes. Subsequently, 0.03 parts by mass of Sn(Cl)₂ were added to the mixed powder and mixed thoroughly. Granulation was performed using a Eurolab 16 co-rotating twin-screw extruder (screw diameter 16 mm, L / D ratio L / D = 40) manufactured by Thermo Fisher Scientific. This extruder has 11 sections from the feed port to the die, numbered 1-11. Section 1 only serves as the feeding section and does not provide heating. Because the properties of the product from this reactive extrusion vary considerably with the formulation, the temperature of each section of the extruder was adjusted accordingly, with the specific temperature being the same as in Example 1 in Table 1. The extrusion reaction time was approximately 5 minutes, and the screw speed was set at 40 rpm. During stable operation, the maximum torque was 20%-30%. The extruder is equipped with a circular die with a diameter of 3 mm. After the sample is extruded from the die and cooled by air, it is cut into cylindrical particles with a diameter of 3 mm by a pelletizer. This is named Comparative Example 6. The particles are then dried in a vacuum oven at 30°C for 5 hours and then packaged for later use.

[0092] Tensile properties were tested on Comparative Example 6. Due to the presence of PLA segments, its tensile strength was reduced to below 20 MPa to a certain extent, making it difficult to meet the strength requirements for subsequent applications.

[0093] The particles obtained above were cast into films on a single-screw extruder at a screw speed of 50 rpm and barrel temperatures of 200℃, 230℃, 230℃, and 220℃.

[0094] The obtained film material was tested according to the above-described method for testing adhesive strength. The maximum load was found to be approximately 0.02 N, which is significantly different from that in Examples 1 to 3.

Claims

1. A biodegradable polyglycolic acid block copolymer, comprising, in parts by mass: (1) 70-90 parts of a polyglycolic acid homopolymer block; and (2) 10-30 parts of a polyethylene glycol block. The biodegradable polyglycolic acid block copolymer is obtained by mixing and melt-extruding components including glycolic acid and / or derivatives thereof and polyethylene glycol, and then performing a reaction, wherein a metal compound catalyst is added in the reaction. The melt-extrusion is performed by a twin-screw extruder, and the reaction temperature is 150-250℃, and the reaction time is 3-20 minutes. The block copolyester has a structure of PEG- b -PGA or PGA- b -PEG- b -PGA; the block copolyester has two glass transition temperatures, at least two melting points; 2.The block copolymer of claim 1, wherein the polymerization monomer of the polyglycolic acid homopolymer is at least one selected from the group consisting of glycolic acid, glycolide, methyl glycolate, and anhydride thereof; and / or the polyethylene glycol is a polymer obtained by ring-opening polymerization of ethylene oxide with water or an alcohol. 3.The block copolymer of claim 2, wherein the polymerization monomer of the polyglycolic acid homopolymer is glycolide. 4.The block copolymer of claim 1, wherein the number average molecular weight of the polyglycolic acid homopolymer block is 1000-100000 g / mol, and the number average molecular weight of the polyethylene glycol block is 200-50000 g / mol. 5.The block copolymer of claim 4, wherein the number average molecular weight of the polyglycolic acid homopolymer block is 2000-80000 g / mol, and the number average molecular weight of the polyethylene glycol block is 1000-20000 g / mol. 6.A method for preparing the biodegradable polyglycolic acid block copolymer of any one of claims 1-5, comprising mixing and melt-extruding components including glycolic acid and / or derivatives thereof and polyethylene glycol, and then performing a reaction, wherein a metal compound catalyst is added in the reaction. The melt-extrusion is performed by a twin-screw extruder. 8.The method of claim 6, wherein the glycolic acid and / or derivatives thereof are at least one selected from the group consisting of glycolic acid, glycolide, methyl glycolate, and anhydride thereof; and / or the number average molecular weight of the polyethylene glycol is 200-50000 g / mol; and / or the amount of the glycolic acid and / or derivatives thereof is 70-90 parts by mass, and the amount of the polyethylene glycol is 10-30 parts by mass. 9.The method of claim 8, wherein the glycolic acid and / or derivatives thereof are glycolide; and / or the number average molecular weight of the polyethylene glycol is 1000-20000 g / mol. 10.The method of claim 6, wherein the metal compound catalyst is a salt compound corresponding to at least one of a group IIA-VA metal element and a transition metal element; and / or ​ ​ 7. The preparation method according to claim 6, characterized in that, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The metal compound catalyst is added in an amount of 0.01 to 0.5 parts based on 100 parts by mass of the total weight of glycolic acid and / or derivatives thereof.

11. The production method according to claim 10, wherein The metal compound catalyst is at least one selected from the group consisting of stannous octoate, stannous chloride, aluminum isopropoxide, bismuth acetate, n-butyl titanate, and tetrabutyl stannate; and / or The metal compound catalyst is added in an amount of 0.03 to 0.3 parts based on 100 parts by mass of the total weight of glycolic acid and / or derivatives thereof.

12. The production method according to claim 11, wherein The metal compound catalyst is stannous chloride.

13. The production method according to claim 6, wherein The extrusion reaction temperature is 150 to 250°C, and the extrusion reaction time is 3 to 20 minutes. The screw rotation speed of the screw extruder is 5 to 150 rpm.

14. The production method according to claim 13, wherein The extrusion reaction temperature is 160 to 230°C, and the extrusion reaction time is 5 to 10 minutes. The screw rotation speed of the screw extruder is 20 to 80 rpm.

15. A polyglycolic acid biodegradable block copolymer film, which is prepared from the polyglycolic acid biodegradable block copolymer according to any one of claims 1 to 5 or from the polyglycolic acid biodegradable block copolymer prepared by the production method according to any one of claims 6 to 14.

16. A production method of the polyglycolic acid biodegradable block copolymer film according to claim 15, which comprises subjecting a component comprising the polyglycolic acid biodegradable block copolymer to extrusion film blowing or casting to obtain the biodegradable block copolymer film.

17. The method of claim 16, wherein the method further comprises, The extrusion film blowing or casting temperature is 180 to 230°C.

18. The method of claim 16, wherein, The heat-pressing temperature of the biodegradable block copolymer film obtained by the production method is 160 to 180°C.

19. The method of claim 18, wherein, The heat-pressing temperature of the biodegradable block copolymer film obtained by the production method is 165 to 175°C.

20. The polyglycolic acid biodegradable block copolymer film according to claim 15 or the polyglycolic acid biodegradable block copolymer film obtained by the production method according to any one of claims 16 to 19, which is used for a biodegradable film product.

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