A polyester polyol, its preparation method and application

Abstract

This invention provides a polyester polyol, its preparation method, and its applications. The raw materials for preparing the polyester polyol include hydroxyl-terminated glycolide oligomers and hydroxyl-terminated butylene succinate oligomers. The preparation method of the hydroxyl-terminated butylene succinate oligomers includes: mixing succinic anhydride with a first 1,4-butanediol, followed by a sequential esterification reaction and a first prepolymerization reaction to obtain the hydroxyl-terminated butylene succinate oligomers. The polyester polyol provided by this invention is a random copolymer, and through the design of its raw materials, the problems of poor atom economy and equipment corrosion in polycondensation methods are solved. Furthermore, the polyurethane prepared using the polyester polyol provided by this invention exhibits excellent mechanical properties, processing performance, and biodegradability, and is non-cytotoxic, demonstrating excellent overall performance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a polyester polyol, its preparation method, and its application. Background Technology

[0002] In the field of medical devices, the application of biodegradable medical materials is becoming increasingly widespread. These materials have gained widespread recognition and favor in the medical community due to their unique biocompatibility, biodegradability, and ability to promote tissue repair and regeneration under certain conditions. In the human body, these materials greatly enhance the patient's treatment experience and recovery outcomes. Currently, the most commonly used biodegradable medical materials include: polylactic acid (PLA), polyglycolic acid / polyglycolic acid (PGA), polycaprolactone (PCL), polyhydroxyalkanoates (PHA), polytrimethylene carbonate (PTMC), poly(p-dioxanone) (PPDO), and their copolymers. In the surgical field, polyglycolic acid, polydioxanone, polylactic acid, polylactic acid-polyglycolic acid copolymer (PLGA), and polylactic acid-polytrimethylene carbonate copolymer (PLA-PTMC) have all been used in registered and marketed medical devices, including absorbable interface anchors, absorbable cranial locks, absorbable screws, and absorbable surgical sutures. In the aesthetic medicine field, polycaprolactone and polylactic acid are used for facial filling to correct moderate to severe nasolabial folds, bringing significant economic benefits. In the cardiovascular field, the application of fourth-generation biodegradable cardiac stents (made of polylactic acid) ensures long-term postoperative safety and effectiveness, avoids late-stage and delayed-onset thrombosis after permanent stent placement, and reduces the incidence of hemangiomas.

[0003] The aforementioned biodegradable medical materials have been widely used, but these materials have certain drawbacks that limit their further application. Polylactic acid (PLA) is hard and brittle, easily broken, requiring toughening or modification for application. For example, PLA-based screws break during service due to insufficient toughness, leading to fixation failure. Polyglycolic acid (PGA) suffers from thermal degradation during processing due to its close melting point and thermal decomposition temperature, resulting in poor processing performance and decreased material properties. Polyhydroxyalkanoates (PHA) are obtained through fermentation, and their high cost and poor batch stability limit their wider application. Polydioxanone (PDA) has poor thermal stability and is prone to thermal degradation during processing, potentially causing medical devices to fail to meet design requirements. Polycaprolactone (PVC) is difficult to synthesize upstream caprolactone monomers, resulting in high cost and poor strength, limiting its application scope. When materials such as PLA and PGA degrade in the human body, acidic products accumulate locally, leading to an acidic environment near implanted devices and inducing inflammation.

[0004] To address the shortcomings of existing biodegradable medical materials, there is an urgent need to develop a novel biodegradable medical material. Polyurethane possesses excellent mechanical and processing properties, and it has been widely proven to have excellent biocompatibility and blood compatibility. More importantly, its unique chemical structure allows for the free design of polyurethane structures to achieve a range of desired properties. Polyurethane combines toughness and strength, and its hardness and elasticity can be adjusted according to usage requirements. Polyurethane can also be processed and molded through injection molding, extrusion, blow molding, etc., and can be used to manufacture medical devices with complex shapes and different sizes, making it easy to process and mold. By designing the chemical structure of polyurethane, biodegradable polyurethane with excellent degradation properties can be synthesized. Furthermore, biodegradable polyurethane does not produce the local accumulation of acidic products during degradation in the human body, thus avoiding the induction of inflammation and reducing the risk of complications in related patients (Research on the Synthesis, Functional Modification and Medical Application of Bio-based Biodegradable Polyurethane [D]. Feng Zhaoxuan. Beijing University of Science and Technology, 2021.).

[0005] One of the key aspects of biodegradable polyurethane lies in the design and synthesis of polyols. The structure and molecular weight of polyols directly affect the degradation rate, mechanical properties, and biocompatibility of polyurethane. Introducing biodegradable polyesters into polyurethane can synthesize high-performance biodegradable polyurethanes. In recent years, biodegradable polybutylene succinate (PBS) has been industrialized and is widely used in agricultural mulch films (CN113321905A) and food packaging (CN118221980A). While there are no registration applications for medical devices made from PBS, in-depth research has been conducted on its biocompatibility and biomedical applications. Luca Cicerod et al. used polybutylene succinate (PBS) to prepare scaffolds that promoted regeneration in cases of extreme nerve injury, and the scaffolds were completely absorbed within 120 days of implantation (Cicero L, et al. Polybutylene succinate artificial scaffold for peripheral nerve regeneration[J]. J Biomed Mater ResB, 2021, 110(1), 125-134.); Vigni et al. applied PBS scaffolds to bone regeneration, achieving enhanced bone regeneration (Vigni GE, et al. Improved bone regeneration using biodegradable polybutylene succinate artificial scaffold in a rabbit model[J]. J FunctBiomater, 2023, 14(1), 22). These studies demonstrate the promising prospects of PBS in biomedical and medical device applications. Therefore, the preparation of PBS-based polyester polyols from PBS and its copolymers has broad application potential in the synthesis of biodegradable polyurethanes for medical applications.

[0006] Commonly used synthesis methods for polybutylene succinate-based polyester polyols include (1) polycondensation, (2) ring-opening polymerization, and (3) transesterification. Polycondensation synthesizes polyester polyols through the polycondensation reaction of diacids and diols. Polycondensation has low production efficiency, generates small molecule water, has poor atom economy, and the raw materials corrode equipment. Transesterification uses the transesterification reaction between polyols and esters to obtain polyester polyols. The resulting products have good quality and do not corrode equipment, but the monomer cost of this method is relatively high. Ring-opening polymerization synthesizes polyester polyols by ring-opening chain growth of cyclic monomers and polyols under the action of a catalyst, but it has high process requirements and certain requirements for the substrate. In recent years, the preparation of polybutylene succinate and its copolymers using tetrahydrofuran, succinic anhydride, and other cyclic monomers through ring-opening has been widely studied. CN113087884A uses Lewis acids or protic acids as catalysts and succinic anhydride and tetrahydrofuran as raw materials to synthesize polybutylene succinate through ring-opening. However, due to the low-strain five-membered ring of tetrahydrofuran, the synthesis of polybutylene succinate is relatively difficult. Further processing is required to obtain polyester polyols from succinic anhydride and tetrahydrofuran, increasing the complexity of the process. Furthermore, the presence of ether bonds on the polymer chain in this alternating polymerization process is detrimental to the degradation of polyurethane (Qing ZQ, et al. Organo-Catalyzed Cationic Ring-Opening Copolymerization of Cyclic Anhydrides with Oxolanes: Access to StructurallyDiverse Polyesters[J]. Macromolecules 2024, 57, 98-109.). CN102964581A discloses the preparation of succinic anhydride-based polyester polyols. After complete leaching, a vacuum pump is started. In actual synthesis, due to the low molecular weight of the prepolymer at this time, the high vacuum degree will cause the low molecular weight prepolymer to be extracted, clogging the pipeline, resulting in synthesis failure or obtaining low-quality polyester polyols.

[0007] In summary, currently widely used biodegradable medical materials—polyesters—exhibit the problem of localized accumulation of acidic byproducts, which can induce inflammation. Furthermore, PGA and PPDO materials have poor processing performance, PLA has poor toughness, and PCL has poor mechanical properties. To address these issues, the development of a novel biodegradable material is urgently needed. Polyurethane possesses excellent mechanical and processing properties, making it a superior biomaterial. Developing biodegradable polyurethane to solve some of the problems associated with biodegradable polyesters is a feasible approach. The key to designing biodegradable polyurethane lies in the design and synthesis methods of soft segments—polyester polyols. Current methods for synthesizing polyester polyols, especially those for polybutylene succinate-based polyester polyols, have limitations and cannot yield high-quality polyester polyols. Therefore, there is an urgent need to provide a high-quality polyester polyol for polyurethane preparation. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a polyester polyol, its preparation method, and its applications. The polyester polyol provided by the present invention solves the problems of poor atom economy and equipment corrosion in polycondensation by designing its raw materials. In addition, the polyurethane prepared using the polyester polyol provided by the present invention has excellent mechanical properties and processing properties, and is non-cytotoxic, exhibiting excellent overall performance.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a polyester polyol, wherein the raw materials for preparing the polyester polyol include hydroxyl-terminated glycolide oligomer and hydroxyl-terminated butylene succinate oligomer; the method for preparing the hydroxyl-terminated butylene succinate oligomer includes: mixing succinic anhydride with a first 1,4-butanediol and then sequentially performing an esterification reaction and a first prepolymerization reaction to obtain the hydroxyl-terminated butylene succinate oligomer.

[0011] The polyester polyol prepared by the present invention through hydroxyl-terminated glycolide oligomer and hydroxyl-terminated butylene succinate oligomer has structural units as shown in Formula I. Its randomness is 1 as determined by nuclear magnetic resonance hydrogen spectroscopy analysis. Therefore, the polyester polyol provided by the present invention is a random copolymer.

[0012]

[0013] Formula I.

[0014] This invention prepares hydroxyl-terminated butylene succinate oligomers from succinic anhydride. Since succinic anhydride can be obtained by hydrogenation of maleic anhydride from upstream, it has a cost advantage over dimethyl succinate, thus solving the problem of high raw material costs in the transesterification method.

[0015] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0016] As a preferred technical solution, the water content of the polyester polyol is ≤0.02%, for example, it can be 0.002%, 0.004%, 0.006%, 0.008%, 0.01%, 0.012%, 0.014%, 0.016%, 0.018%, etc.

[0017] Preferably, the acid value of the polyester polyol is 1-1.5 mgKOH / g, for example, it can be 1.12 mgKOH / g, 1.15 mgKOH / g, 1.18 mgKOH / g, 1.2 mgKOH / g, 1.22 mgKOH / g, 1.25 mgKOH / g, 1.28 mgKOH / g, 1.3 mgKOH / g, 1.32 mgKOH / g, 1.35 mgKOH / g, 1.38 mgKOH / g, 1.4 mgKOH / g, 1.42 mgKOH / g, 1.45 mgKOH / g, 1.48 mgKOH / g, etc.

[0018] Preferably, the hydroxyl value of the polyester polyol is 100-250 mgKOH / g, for example, it can be 110 mgKOH / g, 120 mgKOH / g, 130 mgKOH / g, 140 mgKOH / g, 150 mgKOH / g, 160 mgKOH / g, 170 mgKOH / g, 180 mgKOH / g, 190 mgKOH / g, 200 mgKOH / g, 210 mgKOH / g, 220 mgKOH / g, 230 mgKOH / g, 240 mgKOH / g, etc.

[0019] Preferably, the molecular weight of the polyester polyol is 0.5-4 kDa (for example, it can be 0.8 kDa, 1 kDa, 1.2 kDa, 1.5 kDa, 1.8 kDa, 2 kDa, 2.2 kDa, 2.5 kDa, 2.8 kDa, 3 kDa, 3.2 kDa, 3.5 kDa, 3.8 kDa, etc.), and more preferably 0.5-1 kDa.

[0020] Preferably, the polyester polyol contains 3-80 mol% of glycolide units (based on a total molar percentage of succinic anhydride-based units and glycolide units, with a total molar percentage of 100 mol%). More preferably, the glycolide units can be 5-40 mol% (e.g., 5 mol%, 10 mol%, 15 mol%, 20 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 75 mol%, etc.).

[0021] Preferably, the molar ratio of succinic anhydride to the first 1,4-butanediol is 1:(1.1-2), for example, it can be 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, etc.

[0022] Preferably, the temperature of the esterification reaction is 160-200℃, for example, it can be 162℃, 165℃, 168℃, 170℃, 172℃, 175℃, 178℃, 180℃, 182℃, 185℃, 188℃, 190℃, 192℃, 195℃, 198℃, etc.

[0023] Preferably, the esterification reaction time is 60-120 min, for example, it can be 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min, 100 min, 105 min, 110 min, 115 min, etc.

[0024] Preferably, the esterification reaction is carried out in the presence of a first catalyst.

[0025] Preferably, the first catalyst comprises any one or a combination of at least two of tin oxide, zinc dichloride, zinc sulfate hydrate, calcium chloride, copper chloride, aluminum chloride, or p-benzylsulfonic acid, and more preferably p-benzylsulfonic acid and / or zinc dichloride.

[0026] Preferably, based on the mass of the succinic anhydride as 100%, the mass of the first catalyst is 0.01-0.2%, for example, it can be 0.011%, 0.012%, 0.013%, 0.014%, 0.015%, 0.016%, 0.017%, 0.018%, 0.019%, etc.

[0027] Preferably, the pressure of the first prepolymerization reaction is 5-20 kPa, for example, it can be 6 kPa, 7 kPa, 8 kPa, 9 kPa, 10 kPa, 11 kPa, 12 kPa, 13 kPa, 14 kPa, 15 kPa, 16 kPa, 17 kPa, 18 kPa, 19 kPa, etc.

[0028] Preferably, the temperature of the first prepolymerization reaction is 180-220℃, for example, it can be 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, etc.

[0029] Preferably, the time for the first prepolymerization reaction is 10-40 min, for example, it can be 12 min, 15 min, 18 min, 20 min, 22 min, 25 min, 28 min, 30 min, 32 min, 35 min, 38 min, etc.

[0030] Preferably, the method for preparing the hydroxyl-terminated glycolide oligomer includes:

[0031] The glycolide and second 1,4-butanediol undergo a first reaction to obtain the hydroxyl-terminated glycolide oligomer, as shown in the following reaction formula:

[0032] .

[0033] This invention uses succinic anhydride, glycolide, and 1,4-butanediol as raw materials to prepare polyester polyols. Compared with using succinic acid, glycolic acid, and 1,4-butanediol as raw materials for condensation polymerization to prepare polyester polyols, this invention solves the problems of poor atom economy and equipment corrosion in the condensation polymerization method.

[0034] Preferably, the molar ratio of glycolide to second 1,4-butanediol is 1:(1-3), for example, it can be 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, etc.

[0035] Preferably, the temperature of the first reaction is 140-240℃, for example, it can be 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, etc.

[0036] Preferably, the reaction time is 10-180 min, for example, it can be 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min, etc.

[0037] Preferably, the first reaction is carried out under an inert atmosphere.

[0038] Preferably, the first reaction is carried out in the presence of a second catalyst.

[0039] Preferably, the second catalyst comprises any one or a combination of at least two of bismuth chloride, bismuth oxide, bismuth trifluoromethanesulfonate, 2-ethylbismuth acetate, stannous octoate, stannous acetate, or di-n-octyltin dilaurate, and more preferably any one or a combination of at least two of bismuth chloride, 2-ethylbismuth acetate, or stannous octoate.

[0040] Preferably, based on the mass of the glycolide as 100%, the mass of the second catalyst is 0.01-0.035%, for example, it can be 0.012%, 0.014%, 0.016%, 0.018%, 0.02%, 0.022%, 0.024%, 0.026%, 0.028%, 0.03%, 0.032%, 0.034%, etc.

[0041] Preferably, the ratio of the total mass of the monomers of the hydroxyl-terminated glycol lactide oligomer to the total mass of the monomers of the hydroxyl-terminated butylene succinate oligomer is (0.03-7.8):1, for example, it can be 0.04:1, 0.05:1, 0.1:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, etc.

[0042] In a second aspect, the present invention provides a method for preparing a polyester polyol as described in the first aspect, the method comprising:

[0043] After mixing the hydroxyl-terminated glycolide oligomer with the hydroxyl-terminated butylene succinate oligomer, a second prepolymerization reaction and a second reaction are carried out sequentially to obtain the polyester polyol.

[0044] In the method for preparing polyester polyols provided by this invention, hydroxyl-terminated glycolide oligomers and hydroxyl-terminated butylene succinate oligomers undergo a prepolymerization reaction, which can solve the problems of pipe blockage and material loss in the process of preparing polyester polyols.

[0045] Preferably, the temperature of the second prepolymerization reaction is 160-200℃, for example, it can be 162℃, 165℃, 168℃, 170℃, 172℃, 175℃, 178℃, 180℃, 182℃, 185℃, 188℃, 190℃, 192℃, 195℃, 198℃, etc.

[0046] Preferably, the time for the second prepolymerization reaction is 30-150 min, for example, it can be 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, etc.

[0047] Preferably, the pressure of the second prepolymerization reaction is 5-20 kPa, for example, it can be 6 kPa, 7 kPa, 8 kPa, 9 kPa, 10 kPa, 11 kPa, 12 kPa, 13 kPa, 14 kPa, 15 kPa, 16 kPa, 17 kPa, 18 kPa, 19 kPa, etc.

[0048] Preferably, the second prepolymerization reaction is carried out in the presence of a third catalyst and / or a heat stabilizer.

[0049] Preferably, the third catalyst comprises any one or a combination of at least two of tetrabutyl titanate, isopropyl titanate, or titanium glycolate, and more preferably titanium glycolate and / or tetrabutyl titanate.

[0050] Preferably, based on the mass of the hydroxyl-terminated butylene succinate oligomer as 100%, the mass of the third catalyst is 0.02-0.09%, for example, it can be 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, 0.05%, 0.055%, 0.06%, 0.065%, 0.07%, 0.075%, 0.08%, 0.085%, etc.

[0051] Preferably, the heat stabilizer comprises any one or a combination of at least two of phosphoric acid, trimethyl phosphate, or disodium hydrogen phosphate.

[0052] Preferably, the heat stabilizer is 2-8 ppm based on 100% of the mass of the hydroxyl-terminated glycolide oligomer, for example, 2.5 ppm, 3 ppm, 3.5 ppm, 4 ppm, 4.5 ppm, 5 ppm, 5.5 ppm, 6 ppm, 6.5 ppm, 7 ppm, 7.5 ppm, etc.

[0053] Preferably, the temperature of the second reaction is 210-260℃, for example, it can be 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, etc.

[0054] Preferably, the pressure of the second reaction is 15-30 Pa, for example, it can be 16 Pa, 17 Pa, 18 Pa, 19 Pa, 20 Pa, 21 Pa, 22 Pa, 23 Pa, 24 Pa, 25 Pa, 26 Pa, 27 Pa, 28 Pa, 29 Pa, etc.

[0055] Preferably, the second reaction time is 1-5 hours, for example, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, 4 hours, 4.2 hours, 4.5 hours, 4.8 hours, etc.

[0056] Thirdly, the present invention provides a polyurethane, wherein the raw materials for preparing the polyurethane include polyester polyol, aliphatic isocyanate and chain extender as described in the first aspect.

[0057] This invention modulates the structure of polyester polyols to regulate the degradation and mechanical properties of polyurethane. The resulting polyurethane exhibits excellent biocompatibility, blood compatibility, mechanical properties, and processability, and is non-toxic. It can be processed and molded through injection molding, extrusion, blow molding, etc., and can be used to manufacture medical devices with complex shapes and different sizes. It is easy to process and mold. Compared with biodegradable materials obtained by bio-fermentation, the polyurethane provided by this invention has a significant cost advantage and good batch stability, which can solve the problems of high brittleness, poor processability, and high cost of current biodegradable materials, resulting in superior overall performance. Furthermore, the polyurethane provided by this invention does not produce local accumulation of acidic products during degradation in the human body, thus avoiding the induction of inflammation and reducing the risk of complications for related patients. It can be widely used in the field of medical devices for the manufacture of in vivo and in vitro biodegradable medical devices, with broad applications in fracture repair, vascular repair, tissue engineering, drug sustained release, and biosensors.

[0058] Preferably, the aliphatic isocyanate includes any one or a combination of at least two of hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, or L-lysine diisocyanate.

[0059] Preferably, the chain extender comprises any one or a combination of at least two of ethylene glycol, propylene glycol, 1,4-butanediol or 1,6-hexanediol.

[0060] Preferably, the molar ratio of the polyester polyol to the aliphatic isocyanate is 1:(1.1-17), for example, it can be 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, etc.

[0061] Preferably, the molar ratio of the chain extender to the polyester polyol is (0.01-15):1, for example, it can be 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, etc.

[0062] Preferably, the mass percentage of hard segments in the polyurethane is 20-80%, for example, it can be 22%, 24%, 26%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 74%, 76%, 78%, etc.

[0063] In this invention, the term "hard segment" refers to the rigid portion of the polyurethane molecular chain, which is composed of structural units formed by the reaction of isocyanate and chain extender.

[0064] Preferably, the R value of the polyurethane is 1-1.05, for example, it can be 1.01, 1.02, 1.03, 1.04, etc.

[0065] In this invention, the formula for calculating the R value is: ,in This represents the molar amount of isocyanate groups. This represents the molar amount of hydroxyl groups.

[0066] Preferably, the number-average molecular weight of the polyurethane is 50-150 kDa, for example, it can be 55 kDa, 60 kDa, 65 kDa, 70 kDa, 75 kDa, 80 kDa, 85 kDa, 90 kDa, 95 kDa, 100 kDa, 105 kDa, 110 kDa, 115 kDa, 120 kDa, 125 kDa, 130 kDa, 135 kDa, 140 kDa, 145 kDa, etc.

[0067] Fourthly, the present invention provides a method for preparing polyurethane as described in the third aspect, the method comprising:

[0068] After the polyester polyol and aliphatic isocyanate undergo a third reaction, a chain extender is added to carry out a fourth reaction to obtain the polyurethane.

[0069] Preferably, the temperature of the third reaction is 70-100℃, for example, it can be 72℃, 75℃, 78℃, 80℃, 82℃, 85℃, 88℃, 90℃, 92℃, 95℃, 98℃, etc.

[0070] Preferably, the time for the third reaction is 120-240 min, for example, it can be 130 min, 140 min, 150 min, 160 min, 170 min, 180 min, 190 min, 200 min, 210 min, 220 min, 230 min, etc.

[0071] Preferably, the third reaction is carried out under a nitrogen atmosphere.

[0072] Preferably, the temperature of the fourth reaction is 70-100℃, for example, it can be 72℃, 75℃, 78℃, 80℃, 82℃, 85℃, 88℃, 90℃, 92℃, 95℃, 98℃, etc.

[0073] Preferably, the time for the fourth reaction is 60-240 min, for example, it can be 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min, 180 min, 190 min, 200 min, 210 min, 220 min, 230 min, etc.

[0074] Fifthly, the present invention provides the application of polyurethane as described in the third aspect in absorbable hemostatic sponges, absorbable hernia repair patches, absorbable interface screws, absorbable stents, artificial blood vessels, or absorbable surgical sutures.

[0075] Compared with the prior art, the present invention has the following beneficial effects:

[0076] The polyester polyol provided by this invention solves the problems of poor atom economy and equipment corrosion in polycondensation by designing the raw materials. The polyurethane prepared using the polyester polyol provided by this invention has excellent mechanical properties, processing properties, and biodegradability, and is non-cytotoxic, exhibiting excellent overall performance. Attached Figure Description

[0077] Figure 1 This is the 1H NMR spectrum of the polyester polyol provided in Example 7;

[0078] Figure 2 This is a partially enlarged view of the 1H NMR spectrum of the polyester polyol provided in Example 7;

[0079] Figure 3 This is another enlarged view of the proton NMR spectrum of the polyester polyol provided in Example 7. Detailed Implementation

[0080] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0081] Example 1

[0082] A polyester polyol, wherein the raw materials for preparing the polyester polyol include hydroxyl-terminated glycolide oligomer, hydroxyl-terminated butylene succinate oligomer, trimethyl phosphate and titanium glycolate.

[0083] The preparation method of the polyester polyol includes:

[0084] 0.5 mol of succinic anhydride and 1,4-butanediol were added to a reaction vessel at a molar ratio of 1:1.6, and 0.1% p-benzenesulfonic acid by weight of succinic anhydride was added. The esterification reaction was carried out at 180°C for 90 min. Then, the water in the system was removed at 10 kPa and 200°C, and a first prepolymerization reaction was carried out for 30 min to obtain the hydroxyl-terminated butylene succinate oligomer.

[0085] Before the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace amounts of moisture, volatile gases, and impurities. Then, the reaction vessel was filled with dry, inert gas. Under a dry, inert atmosphere, 0.026 mol of glycolide and 1,4-butanediol were added to the reaction vessel filled with dry, inert gas at a molar ratio of 1:1. 0.02% of stannous octoate by weight of glycolide was added as a catalyst, and the first reaction was carried out at 160°C for 120 min to obtain the hydroxyl-terminated glycolide oligomer.

[0086] The obtained hydroxyl-terminated glycolide oligomer was added to the obtained hydroxyl-terminated butylene succinate oligomer under a nitrogen atmosphere, along with 0.09% titanium glycolide (the amount of the hydroxyl-terminated butylene succinate oligomer) and 8 ppm trimethyl phosphate (the amount of the hydroxyl-terminated glycolide oligomer). A second prepolymerization reaction was carried out at 200°C and 10 kPa for 60 min. Then, the temperature was raised to 220°C, and the pressure was maintained at 15 Pa for a second reaction of 120 min. The product was discharged after the acid value, hydroxyl value, and water content of the polyester polyol met the requirements. The proportions of each raw material are shown in Table 1.

[0087] Examples 2-8

[0088] A polyester polyol and its preparation method are disclosed. The only difference between this method and Example 1 is the amount of glycolide, succinic anhydride, and 1,4-butanediol used, as shown in Table 1. All other raw materials, process parameters, and steps are the same as in Example 1.

[0089] Example 9

[0090] A polyester polyol, wherein the raw materials for preparing the polyester polyol include hydroxyl-terminated glycolide oligomer, hydroxyl-terminated butylene succinate oligomer, phosphoric acid, and tetrabutyl titanate.

[0091] The preparation method of the polyester polyol includes:

[0092] 0.5 mol of succinic anhydride and 1,4-butanediol were added to a reaction vessel at a molar ratio of 1:1.6, and 0.1% p-benzenesulfonic acid by weight of succinic anhydride was added. The esterification reaction was carried out at 160 °C for 120 min. Then, the water in the system was removed at 10 kPa and 200 °C, and a first prepolymerization reaction was carried out for 30 min to obtain the hydroxyl-terminated butylene succinate oligomer.

[0093] Before the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace amounts of moisture, volatile gases, and impurities. Then, the reaction vessel was filled with dry, inert gas. Under a dry, inert atmosphere, 0.026 mol of glycolide and 1,4-butanediol were added to the reaction vessel filled with dry, inert gas at a molar ratio of 1:1.5. 0.02% of stannous octoate by weight of glycolide was added as a catalyst, and the first reaction was carried out at 160°C for 120 min to obtain the hydroxyl-terminated glycolide oligomer.

[0094] The obtained hydroxyl-terminated glycolide oligomer was added to the obtained hydroxyl-terminated butylene succinate oligomer under a nitrogen atmosphere, along with 0.09% tetrabutyl titanate by weight of the hydroxyl-terminated butylene succinate oligomer and 8 ppm phosphoric acid by weight of the hydroxyl-terminated glycolide oligomer. The second prepolymerization reaction was carried out at 200°C and 10 kPa for 60 min. Then, the temperature was raised to 220°C and the pressure was maintained at 15 Pa for 120 min for the second reaction. The product was discharged after the acid value, hydroxyl value and water content of the polyester polyol met the requirements. The reaction conditions are shown in Table 2.

[0095] Examples 10-19

[0096] A polyester polyol and its preparation method are disclosed. The only difference between this method and Example 9 is the preparation process parameters, as shown in Table 2. The raw materials used in the preparation are the same as those in Example 9.

[0097] Comparative Example 1

[0098] A polyester polyol and its preparation method, the preparation method comprising the following steps:

[0099] (1) Before the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace amounts of moisture, volatile gases and impurities. Then, the reaction vessel was filled with dry inert gas. 0.5 mol succinic anhydride, 0.839 mol 1,4-butanediol and 0.026 mol glycolide were added to the reaction vessel filled with dry inert gas under a dry inert atmosphere. 0.1% p-benzenesulfonic acid by weight of succinic anhydride was added, and the esterification reaction was carried out at 180°C for 90 min.

[0100] (2) Add 0.2% succinic anhydride by mass of titanium glycol and 15 ppm trimethyl phosphate by mass of glycolide to the solution after the above esterification reaction. Remove the water in the system at 200°C and 10 kPa and perform prepolymerization for 60 min. Further increase the temperature to 220°C and maintain the pressure at 15 Pa. After reacting for 120 min, discharge the material to obtain the polyester polyol.

[0101] Comparative Example 2

[0102] A polyester polyol and its preparation method, the preparation method comprising the following steps:

[0103] (1) Add 0.5 mol of succinic anhydride and 1,4-butanediol to the reaction vessel at a molar ratio of 1:1.6, add 0.1% p-benzenesulfonic acid by weight of succinic anhydride, and carry out the esterification reaction at 180℃ for 90 min;

[0104] Before the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace amounts of moisture, volatile gases, and impurities. Then, the reaction vessel was filled with dry, inert gas. Under a dry, inert atmosphere, 0.026 mol of glycolide and 1,4-butanediol were added to the reaction vessel filled with dry, inert gas at a molar ratio of 1:1.5. 0.02% of the weight of glycolide in stannous octoate was added as a catalyst, and the reaction was carried out at 160°C for 120 min to obtain hydroxyl-terminated glycolide oligomers.

[0105] (2) The hydroxyl-terminated glycolide oligomer was added to the solution after esterification under a nitrogen atmosphere, and 0.2% of succinic anhydride by mass of titanium glycolide and 8 ppm of hydroxyl-terminated glycolide oligomer by mass of trimethyl phosphate were added. The temperature was further increased to 220°C, the pressure was maintained at 15 Pa, and the reaction was carried out for 120 min before the product was discharged to obtain the polyester polyol.

[0106] Comparative Example 3

[0107] A polyester polyol and its preparation method, the preparation method comprising the following steps:

[0108] Hydroxyl-terminated glycolide oligomer was added to hydroxyl-terminated butylene succinate oligomer under a nitrogen atmosphere, along with 0.09% titanium glycolide (the amount of hydroxyl-terminated butylene succinate oligomer) and 8 ppm trimethyl phosphate (the amount of hydroxyl-terminated glycolide oligomer). The mixture was reacted at 220°C and 15 Pa for 120 min, and then discharged to obtain the polyester polyol.

[0109] The preparation methods for the hydroxyl-terminated glycolide oligomer and the hydroxyl-terminated butylene succinate oligomer are the same as in Example 8.

[0110] Comparative Example 4

[0111] A polyester polyol and its preparation method, the preparation method comprising the following steps:

[0112] (1) Before the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace amounts of moisture, volatile gases and impurities. Then, the reaction vessel was filled with dry inert gas. Under a dry inert atmosphere, 0.026 mol of glycolide and 1,4-butanediol were added to the reaction vessel filled with dry inert gas at a molar ratio of 1000:1. 0.02% of the weight of glycolide in stannous octoate was added as a catalyst. The first reaction was carried out at 160°C for 120 min to obtain solid hydroxyl-terminated polyethylene glycolide (polymer).

[0113] (2) The hydroxyl-terminated polyglycolic acid was crushed and added to the hydroxyl-terminated butylene succinate oligomer under a nitrogen atmosphere. 0.09% of the hydroxyl-terminated butylene succinate oligomer mass of titanium glycolate and 8 ppm of the hydroxyl-terminated polyglycolic acid trimethyl phosphate were added. The prepolymerization reaction was carried out at 200°C and 10 kPa for 60 min. Then the reaction was carried out at 220°C and 15 Pa for 120 min.

[0114] The preparation method of the hydroxyl-terminated butylene succinate oligomer is the same as in Example 1.

[0115] Table 1

[0116]

[0117] Table 2

[0118]

[0119] Characterization of polyester polyols

[0120] (1) Molar percentage n of glycolide units in polyester polyol GL (mol%)

[0121] The molar percentage of glycolide units was calculated based on the 1H NMR spectrum and Equation 1. Taking the polyester polyol provided in Example 7 as an example, its 1H NMR spectrum is as follows: Figure 1 As shown, the chemical shifts 4.63-4.82 ppm represent the methylene peak of the glycolide unit, 4.12-4.20 ppm represent the methylene peak of the 1,4-butanediol unit, and 2.62-2.80 ppm represent the methylene peak of the succinic anhydride unit. Figure 2-3 This is a partially enlarged view of the 1H NMR spectrum of the polyester polyol provided in Example 7, based on... Figure 2-3The molar percentage of glycolide units can be calculated using the following formula: (Equation 1);

[0122] Among them, I g I is the sum of the peak areas of g1, g2, g3, and g4. s It is the sum of the peak areas of s1, s2 (a total of 3 peaks), s3 (a total of 3 peaks), and s4.

[0123] (2) Water content of polyester polyol: The water content of polyol used in the production of polyurethane is determined according to GB / T 22313-2008.

[0124] (3) Acid value: The acid value was determined according to HG / T 2708-1995 Determination of acid value in polyester polyols.

[0125] (4) Hydroxyl value: The hydroxyl value was determined according to HG / T 2709-2022 Determination of hydroxyl value of polyester polyols used in the production of polyurethane.

[0126] (5) Molecular weight: The molecular weight of the sample was determined by gel permeation chromatography (GPC) at 40°C using tetrahydrofuran as the mobile phase. The calibration curve was constructed using polystyrene standard samples.

[0127] The polyester polyols provided in Examples 1-19 and Comparative Examples 1-4 were tested according to the above method. The test results are shown in Table 3. In Table 3, " / " indicates that there is no relevant test data.

[0128] Table 3

[0129]

[0130] As can be seen from the test data in Table 3, the polyester polyol provided by the present invention is a high-quality polyester polyol with a water content of <0.02%, an acid value of <1.5mgKOH / g, a hydroxyl value of 119.2-205.3mgKOH / g, and a molecular weight of 0.55-1kDa.

[0131] Comparative Example 1, synthesized using a one-pot method, produced polyester polyols with high water content and acid values, failing to meet the requirements for synthesizing biodegradable polyurethane. Comparative Example 2, after esterification, underwent direct high-vacuum polycondensation, resulting in the extraction of a large amount of oligomers from the system, leading to low raw material utilization and pipe blockage, ultimately causing synthesis failure. In Comparative Example 3, the hydroxyl-terminated glycolide oligomers and hydroxyl-terminated butanediol succinate oligomers did not undergo a second prepolymerization reaction. During the second reaction, due to the low molecular weight of the hydroxyl-terminated glycolide oligomers, a boiling-out phenomenon occurred, resulting in the extraction of a large amount of hydroxyl-terminated glycolide oligomers. The ratio of succinic anhydride to glycolide in the polyester polyol deviated significantly from the design value, preventing the synthesis of the required proportion of polyester polyol, thus resulting in synthesis failure. In Comparative Example 4, the molar ratio of glycolide to 1,4-butanediol was too high. As the reaction proceeded, the molecular weight continuously increased, forming a white solid at the bottom of the reactor. Due to the high molecular weight of the hydroxyl-terminated glycolide, it could not melt at 220°C, remaining solid and preventing successful synthesis of the polyester polyol.

[0132] Application Example 1

[0133] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, isophorone diisocyanate and 1,4-butanediol provided in Example 1;

[0134] The method for preparing the polyurethane includes:

[0135] Under nitrogen protection, 64.1 g of the polyester polyol and 50 g of isophorone diisocyanate provided in Example 1 were added to a reaction vessel and reacted at 70°C for 120 min; then 14.1 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0136] Application Example 2

[0137] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, hexamethylene diisocyanate and 1,4-butanediol provided in Example 2;

[0138] Under nitrogen protection, 68.7 g of polyester polyol and 50 g of hexamethylene diisocyanate provided in Example 2 were added to a reaction vessel and reacted at 70°C for 120 min; then 18.7 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0139] Application Example 3

[0140] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, dicyclohexylmethane diisocyanate and 1,4-butanediol provided in Example 3;

[0141] Under nitrogen protection, 60.4 g of the polyester polyol and 50 g of dicyclohexylmethane diisocyanate provided in Example 3 were added to a reaction vessel and reacted at 70°C for 120 min; then 10.4 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0142] Application Example 4

[0143] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, L-lysine diisocyanate and 1,4-butanediol provided in Example 4;

[0144] Under nitrogen protection, 61.6 g of the polyester polyol and 50 g of L-lysine diisocyanate provided in Example 4 were added to a reaction vessel and reacted at 70°C for 120 min; then 11.6 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0145] Application Example 5

[0146] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, hexamethylene diisocyanate and 1,4-butanediol provided in Example 5;

[0147] Under nitrogen protection, 67.8 g of the polyester polyol and 50 g of hexamethylene diisocyanate provided in Example 5 were added to a reaction vessel and reacted at 70°C for 120 min; then 17.8 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0148] Application Example 6

[0149] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, hexamethylene diisocyanate and 1,4-butanediol provided in Example 6;

[0150] Under nitrogen protection, 68.7 g of polyester polyol and 50 g of hexamethylene diisocyanate provided in Example 6 were added to a reaction vessel and reacted at 70°C for 120 min; then 18.7 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0151] Application Example 7

[0152] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, hexamethylene diisocyanate and 1,4-butanediol provided in Example 7;

[0153] Under nitrogen protection, 68.5 g of the polyester polyol and 50 g of hexamethylene diisocyanate provided in Example 7 were added to a reaction vessel and reacted at 70°C for 120 min; then 18.5 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0154] Application Example 8

[0155] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, hexamethylene diisocyanate and 1,4-butanediol provided in Example 8;

[0156] Under nitrogen protection, 66.1 g of the polyester polyol and 50 g of hexamethylene diisocyanate provided in Example 8 were added to a reaction vessel and reacted at 70°C for 120 min; then 16.1 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0157] Application Example 9

[0158] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, hexamethylene diisocyanate and 1,4-butanediol provided in Example 1;

[0159] Under nitrogen protection, 220.6 g of polyester polyol and 50 g of hexamethylene diisocyanate provided in Example 1 were added to a reaction vessel and reacted at 70°C for 120 min; then 5.1 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0160] Application Example 10

[0161] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, hexamethylene diisocyanate and 1,4-butanediol provided in Example 1;

[0162] Under nitrogen protection, 18.6 g of the polyester polyol and 50 g of hexamethylene diisocyanate provided in Example 1 were added to a reaction vessel and reacted at 70°C for 120 min; then 24.5 g of 1,4-butanediol was added as a chain extender, and the reaction was continued at 80°C for 150 min to obtain the polyurethane.

[0163] Product characterization and performance testing

[0164] (1) Hard segment content: ×100%;

[0165] (2) Number-average molecular weight: The molecular weight of the sample was determined by gel permeation chromatography (GPC) at 40°C using tetrahydrofuran as the mobile phase. The calibration curve was constructed using polystyrene standard samples.

[0166] (3) Elongation at break and tensile strength: The tensile properties of plastics shall be determined in accordance with GB / T 1040.

[0167] (4) Melting temperature T m Analysis was performed using a differential scanning calorimeter (Netzsch DSC 214 polyma) under a nitrogen atmosphere. The nitrogen flow rate was 20 mL / min. The sample was heated from 25 °C to 165 °C at a rate of 10 °C / min and held for 1 min to eliminate thermal history. Then, it was cooled to −60 °C at a rate of 10 °C / min and held for 1 min. Finally, the sample was heated back to 165 °C at a rate of 10 °C / min.

[0168] (5) Thermal decomposition temperature T d,5% The results were obtained using a thermogravimetric analyzer (Netzsch TG 209 F3 Tarsus) under N2 atmosphere, with the temperature increased from 40℃ to 700℃ at a heating rate of 10℃ / min.

[0169] (6) Cytotoxicity: In vitro cytotoxicity test (MTT cytotoxicity test) shall be conducted in accordance with GB / T 16886.5-2017; when the survival rate of live cells decreases to <70% of the blank, it has potential cytotoxicity and is defined as poor; when the survival rate of live cells is ≥70% of the blank, it is defined as good.

[0170] The polyurethanes provided in Application Examples 1-10 were tested according to the above method, and the test results are shown in Table 4. The data for PLA, PGA, PCL, PPDO, and PHA in Table 4 are publicly available data in the prior art. The relevant data for PLA are from: Mehta, R. et al. Synthesis of Poly(Lactic Acid): A Review[J]. Journal of Macromolecular Science Part C, 2005, 45(5): 325-349. The relevant data for PGA are from: Middleton, JC. et al. Synthetic biodegradable polymers as orthopedic devices[J]. Biomaterials, 2000, 21(23): 2335-2346. The relevant data for PCL are from: Gong Caihong. Preparation and oligomer regulation of polycaprolactone[D]. Hunan Normal University, 2021; Han Lei. Preparation and performance study of polycaprolactone self-reinforced composite materials[D]. Donghua University, 2018. The relevant data for PPDO are from: Yuan, Y. et al. Influences of Bis-(2,6-Diisopropylphenyl) Carbodiimide on the Thermal Stability and Crystallization of Poly(P-Dioxanone)[J]. Journal of Macromolecular Science. Patt B, Physics, 2016, 55(5):532-546; Zhang, J F. et al. Influence of thermalannealing on mechanical properties and in vitro degradation of poly(p-dioxanone)[J]. Polymer Engineering and Science, 2019, 59(8):1701-1709. Relevant data on PHA comes from: Zhang Xiangnan. Study on the properties of poly(3-hydroxybutyrate) and poly(4-hydroxybutyrate)[J]. Plastics Technology, 2011, 39(05):57-62. Biocompatibility data of PLA, PHA, and PCL come from: Mi, CH. et al. Advances in medical polyesters for vascular tissue engineering[J].Discover Nano, 2024, 19, 125. Biocompatibility data for PPDO comes from: Lu J. L, et al. 3D-Printed Poly (P-Dioxanone) Stent for Endovascular Application: In Vitro Evaluations[J]. Polymers, 2022, 14(9): 1755. Biocompatibility data for PGA comes from: Fu S. J, et al. SurfaceCoating Modified Polyglycolide (PGA) Braided Threads as Potential Thread-embedding Materials[J]. Fibers Polym, 2020, 21, 2401-2406.

[0171] Table 4

[0172]

[0173] As shown in Table 4, the polyurethane provided by this invention possesses excellent comprehensive properties, with a tensile strength of 21.6-60.3 MPa and an elongation at break of 421-963%. Its mechanical properties can meet the application requirements in various scenarios and exhibit excellent biocompatibility. Compared to PGA and PPDO, the polyurethane provided by this invention has a higher decomposition temperature (T0). d,5% With a melting point and decomposition temperature significantly different (>250℃), it exhibits excellent processing properties. Compared to PLA, PGA, and PHA, the polyurethane provided by this invention possesses superior toughness; compared to PCL, the polyurethane provided by this invention has higher tensile strength.

[0174] (7) Mass loss rate test: After the polyurethane was melted, it was hot-pressed into a film at 150℃ and 5MPa using a mold, and then sliced ​​(1×2cm, 0.8mm thick). The slices were dried in a vacuum oven at 40℃ until constant weight, and the initial mass M0 was measured. Then, the polyurethane slices were placed in a phosphate buffer solution (pH 7.4) at 37℃ for in vitro degradation experiments. After the predetermined degradation time, the filter material was obtained. The filter material was washed three times with analytical grade II water conforming to GB / T 6682, and dried to constant weight at room temperature and under vacuum. The mass M0 was measured. t The mass loss rate during the degradation process was calculated using the following formula. The higher the mass loss rate, the stronger the degradation ability. The test results are shown in Table 5.

[0175] Quality loss rate = (M0 - M) t ) / M0×100%;

[0176] In the formula: M0 represents the initial mass; M t This represents the mass of the filtered material over day t.

[0177] Table 5

[0178]

[0179] The degradation ability of polyurethane can be controlled by the proportion of glycolide units in the polyester polyol chain. In vitro degradation experiments in Application Examples 5-8 show that increasing the glycolide unit content improves the degradation ability of the polyurethane. Application Examples 1-4 used different diisocyanates to synthesize polyurethane. Different diisocyanates affect the molecular chain regularity of the polyurethane. Because hexamethylene diisocyanate is more regular, the polyurethane obtained from it has high crystallinity and weak degradation ability. Application Examples 9 and 10 show polyurethanes with different hard segment contents; as the hard segment content increases, the degradation ability of the polyurethane decreases.

[0180] The applicant declares that this invention illustrates the polyester polyol, its preparation method, and its application through the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials in the product of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A polyurethane, characterized in that, The raw materials for preparing the polyurethane consist of polyester polyol, aliphatic isocyanate and chain extender; The aliphatic isocyanate is selected from any one of hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate or L-lysine diisocyanate; The molar ratio of the polyester polyol to the aliphatic isocyanate is 1:(1.1-17); The raw materials for preparing the polyester polyol include hydroxyl-terminated glycolide oligomers and hydroxyl-terminated butylene succinate oligomers. The method for preparing the hydroxyl-terminated butylene succinate oligomer includes: Succinic anhydride and first 1,4-butanediol are mixed and then subjected to esterification and first prepolymerization reactions in sequence to obtain the hydroxyl-terminated butylene succinate oligomer. The pressure of the first prepolymerization reaction is 5-20 kPa; The method for preparing the hydroxyl-terminated glycolide oligomer includes: The glycolide and second 1,4-butanediol undergo a first reaction to obtain the hydroxyl-terminated glycolide oligomer; The preparation method of the polyester polyol includes: After the hydroxyl-terminated glycolide oligomer is mixed with the hydroxyl-terminated butylene succinate oligomer, a second prepolymerization reaction and a second reaction are carried out sequentially to obtain the polyester polyol. The polyester polyol has a total molar percentage of 3-80 mol% based on the sum of the molar percentages of succinic anhydride-based units and glycolide units, which is 100 mol%.

2. The polyurethane according to claim 1, characterized in that, The water content of the polyester polyol is ≤0.02%; The acid value of the polyester polyol is 1-1.5 mg KOH / g; The hydroxyl value of the polyester polyol is 100-250 mg KOH / g; The molecular weight of the polyester polyol is 0.5-4 kDa.

3. The polyurethane according to claim 1, characterized in that, The molar ratio of succinic anhydride to the first 1,4-butanediol is 1:(1.1-2); The esterification reaction is carried out at a temperature of 160-200℃; The esterification reaction takes 60-120 minutes; The esterification reaction is carried out in the presence of a first catalyst; The first catalyst comprises any one or a combination of at least two of tin oxide, zinc dichloride, zinc sulfate hydrate, calcium chloride, copper chloride, aluminum chloride, or p-benzenesulfonic acid; Based on the mass of the succinic anhydride being 100%, the mass of the first catalyst is 0.01-0.2%; The temperature of the first prepolymerization reaction is 180-220℃; The first prepolymerization reaction takes 10-40 minutes.

4. The polyurethane according to claim 1, characterized in that, The molar ratio of glycolide to second 1,4-butanediol is 1:(1-3). The temperature of the first reaction is 140-240℃; The first reaction takes 10-180 minutes; The first reaction was carried out under an inert atmosphere; The first reaction is carried out in the presence of a second catalyst; The second catalyst includes any one or a combination of at least two of bismuth chloride, bismuth oxide, bismuth trifluoromethanesulfonate, bismuth 2-ethylacetate, stannous octanoate, stannous acetate, or di-n-octyltin dilaurate; Based on the mass of the glycolide being 100%, the mass of the second catalyst is 0.01-0.035%.

5. The polyurethane according to claim 1, characterized in that, The temperature of the second prepolymerization reaction is 160-200℃; The second prepolymerization reaction takes 30-150 minutes; The pressure of the second prepolymerization reaction is 5-20 kPa; The second prepolymerization reaction is carried out in the presence of a third catalyst and / or a heat stabilizer; The third catalyst includes any one or a combination of at least two of tetrabutyl titanate, isopropyl titanate, or titanium glycolate. Based on the mass of the hydroxyl-terminated butylene succinate oligomer being 100%, the mass of the third catalyst is 0.02-0.09%. The heat stabilizer includes any one or a combination of at least two of phosphoric acid, trimethyl phosphate, or disodium hydrogen phosphate. The heat stabilizer has a mass of 2-8 ppm, based on 100% of the hydroxyl-terminated glycolide oligomer. The temperature of the second reaction is 210-260℃; The pressure of the second reaction is 15-30 Pa; The second reaction takes 1-5 hours.

6. The polyurethane according to claim 1, characterized in that, The chain extender includes any one or a combination of at least two of ethylene glycol, propylene glycol, 1,4-butanediol or 1,6-hexanediol; The molar ratio of the chain extender to the polyester polyol is (0.01-15):

1.

7. The polyurethane according to claim 1, characterized in that, The mass percentage of the hard segment in the polyurethane is 20-80%; The R value of the polyurethane is 1-1.05; The number-average molecular weight of the polyurethane is 50-150 kDa.

8. A method for preparing polyurethane according to any one of claims 1-7, characterized in that, The preparation method includes: After the polyester polyol and aliphatic isocyanate undergo a third reaction, a chain extender is added to carry out a fourth reaction to obtain the polyurethane.

9. The preparation method according to claim 8, characterized in that, The temperature of the third reaction is 70-100℃; The time for the third reaction is 120-240 min; The temperature of the fourth reaction is 70-100℃; The fourth reaction takes 60-240 minutes.

10. The use of polyurethane as described in any one of claims 1-7 in the preparation of absorbable hemostatic sponges, absorbable hernia repair patches, absorbable interface screws, absorbable stents, artificial blood vessels, or absorbable surgical sutures.

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