Polyester polyol as well as preparation method and application thereof

Abstract

The invention provides polyester polyol as well as a preparation method and application thereof. The polyester polyol is prepared from the following raw materials: a hydroxyl-terminated glycolide oligomer and a hydroxyl-terminated butylene succinate oligomer, the preparation method of the hydroxyl-terminated butylene succinate oligomer comprises the following steps: mixing butanedioic anhydride and first 1, 4-butanediol, and sequentially carrying out esterification reaction and first prepolymerization reaction to obtain the hydroxyl-terminated butylene succinate oligomer. The polyester polyol provided by the invention is a random copolymer, and through the design of preparation raw materials, the problems of poor atom economy and equipment corrosion of a polycondensation method are solved; in addition, polyurethane prepared from the polyester polyol provided by the invention has excellent mechanical properties, processability and degradability, is free of cytotoxicity and has excellent comprehensive performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and in particular relates to a polyester polyol and a preparation method and application thereof. Background Art

[0002] In the medical device field, biodegradable medical materials are increasingly being used. Their unique biocompatibility, degradability, and ability to promote tissue repair and regeneration under certain conditions have earned them widespread recognition and favor in the medical community. These materials have significantly enhanced patients' treatment experience and recovery outcomes within the human body. Currently, the most commonly used biodegradable medical materials include polylactic acid (PLA), polyglycolic acid / polyglycolide (PGA), polycaprolactone (PCL), polyhydroxyalkanoates (PHA), polytrimethylene carbonate (PTMC), polydioxanone (PPDO), and their copolymers. In the field of surgery, 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 skull locks, absorbable screws, absorbable surgical sutures, etc.; in the field of medical aesthetics, polycaprolactone and polylactic acid are used for facial filling to correct moderate to severe nasolabial wrinkles, and have brought huge economic benefits; in the cardiovascular field, the application of fourth-generation degradable heart stents (made of polylactic acid) ensures long-term safety and effectiveness after surgery, avoids late and delayed thrombosis in permanent stent surgery, and reduces the incidence of hemangiomas.

[0003] The above-mentioned degradable medical materials have been widely used, but these materials have certain defects that limit their further application. Polylactic acid is hard and brittle and easily breaks. It needs to be toughened or modified during application. For example, polylactic acid-based screws break during service due to insufficient toughness, resulting in fixation failure; polyglycolic acid undergoes thermal degradation during processing due to the close melting point and thermal decomposition temperature, and its processing performance is poor, and the material performance decreases; polyhydroxyalkanoates are obtained by fermentation, and the high cost and poor batch stability limit the wider application of PHA; polydioxanone has poor thermal stability and is prone to thermal degradation during processing, resulting in the performance of the obtained medical devices may not meet the design requirements; the upstream caprolactone monomer of polycaprolactone is difficult to synthesize, resulting in high cost of polycaprolactone and its poor strength, which limits its breadth of application. When materials such as PLA and PGA degrade in the human body, local accumulation of acidic products occurs, resulting in acidity near the implanted device and inducing inflammation.

[0004] To address the shortcomings of existing biodegradable medical materials, there is an urgent need to develop new biodegradable medical materials. Polyurethane has excellent mechanical and processing properties, and it has been widely demonstrated to have excellent biocompatibility and blood compatibility. More importantly, its unique chemical structure allows people to freely design the structure of polyurethane to obtain a range of desired properties. Polyurethane combines toughness and strength, and its hardness and elasticity can be adjusted according to the needs of use. Polyurethane can also be processed and formed through injection molding, extrusion, blow molding, etc., and can be used to manufacture medical devices of complex shapes and different sizes, which are easy to process and form. By designing the chemical structure of polyurethane, biodegradable polyurethane with excellent degradation properties can be synthesized. Degradable polyurethane will not produce localized accumulation of acidic products during degradation in the human body, thus not inducing inflammation, reducing the risk of complications in related patients (Research on the Synthesis, Functional Modification and Medical Application of Bio-based Degradable Polyurethane [D]. Feng Zhaoxuan. Beijing University of Science and Technology, 2021.).

[0005] One of the keys of degradable polyurethane is the design and synthesis of polyols, and the structure and molecular weight of polyols directly affect the degradation rate, mechanical properties and biocompatibility of polyurethane. Degradable polyester is introduced into polyurethane, and degradable polyurethane with excellent performance can be synthesized. In recent years, degradable polybutylene succinate (PBS) has been industrialized and is widely used in fields such as agricultural mulch (CN113321905A), food packaging (CN118221980A). Medical devices prepared with polybutylene succinate do not have registration applications, but have been used in-depth research for its biocompatibility and biomedical aspects. Luca Cicerod et al. used polybutylene succinate to prepare scaffolds to promote the regeneration of extreme nerve damage, and the scaffolds were completely absorbed within 120 days of implantation (Cicero L, et al. Polybutylene succinateartificial scaffold for peripheral nerve regeneration[J]. J Biomed Mater ResB, 2021, 110(1), 125-134.); Vigni et al. used polybutylene succinate scaffolds for bone regeneration and achieved 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 have demonstrated the prospects of polybutylene succinate in biomedical and medical device applications. Therefore, the preparation of polybutylene succinate-based polyester polyols from polybutylene succinate and its copolymers has broad application potential in the synthesis of degradable polyurethanes for medical applications.

[0006] Common methods for synthesizing polybutylene succinate-based polyester polyols include (1) polycondensation, (2) ring-opening, and (3) transesterification. The polycondensation method synthesizes polyester polyols through the polycondensation reaction of dibasic acids and diols. The polycondensation method has low production efficiency, generates small molecules of water, has poor atom economy, and the raw materials corrode equipment. The transesterification method uses polyols and esters to undergo an ester exchange reaction to obtain polyester polyols. The resulting product has good quality and will not corrode equipment, but the cost of the polymerized monomers is relatively high. The ring-opening polymerization method 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 substrate requirements. In recent years, the use of tetrahydrofuran, succinic anhydride, and other cyclic monomers to prepare poly(butylene succinate) and its copolymers by ring-opening has been widely studied. CN113087884A uses Lewis acid or protic acid as a catalyst, and succinic anhydride and tetrahydrofuran as raw materials for ring-opening synthesis of poly(butylene succinate). However, due to the low-tension five-membered ring of tetrahydrofuran, the synthesis of poly(butylene succinate) is relatively difficult. Using succinic anhydride and tetrahydrofuran as raw materials, further processing is required to obtain polyester polyols, which increases the process complexity. In addition, the presence of ether bonds in the polymer chains during the alternating polymerization is not conducive to the degradation of polyurethane (Qing ZQ, et al. Organo-Catalyzed Cationic Ring-Opening Copolymerization of Cyclic Anhydrides with Oxolanes: Access to Structurally Diverse Polyesters[J]. Macromolecules 2024, 57, 98-109.). CN102964581A discloses the preparation of succinic anhydride-based polyester polyols. After the water is completely discharged, the vacuum pump is started. In actual synthesis, due to the low molecular weight of the prepolymer at this time, high vacuum will cause the low molecular weight prepolymer to be extracted, blocking the pipeline, resulting in synthesis failure or obtaining low-quality polyester polyols.

[0007] In summary, the currently widely used degradable medical materials - polyesters, have the problem of local accumulation of acidic degradation products, which can induce inflammation; in addition, PGA and PPDO materials have poor processing performance, PLA has poor toughness, and PCL has poor mechanical properties. In order to solve the above problems, it is urgent to develop a new type of degradable material. Polyurethane has excellent mechanical properties and processing properties and is an excellent biomaterial. Developing degradable polyurethane to solve some of the problems of degradable polyesters is a feasible route, and the focus of degradable polyurethane design lies in the design and synthesis method of the soft segment - polyester polyol. Among the current methods for synthesizing polyester polyols, especially the synthesis method of polybutylene succinate-based polyester polyols, there are defects, and high-quality polyester polyols cannot be obtained. Therefore, there is an urgent need to provide a high-quality polyester polyol for the preparation of polyurethane. Summary of the Invention

[0008] In view of the deficiencies in the prior art, the present invention aims to provide a polyester polyol, a preparation method and application thereof. The polyester polyol provided by the present invention solves the problems of poor atom economy and equipment corrosion in the polycondensation method through the design of its preparation raw materials. In addition, the polyurethane prepared using the polyester polyol provided by the present invention has excellent mechanical properties and processing properties, is non-cytotoxic, and has excellent overall performance.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a polyester polyol, wherein the raw materials for preparing the polyester polyol include a hydroxyl-terminated glycolide oligomer and a hydroxyl-terminated butylene succinate oligomer; the preparation method of the hydroxyl-terminated butylene succinate oligomer includes: mixing succinic anhydride and 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 hydroxyl-terminated glycolide oligomers and hydroxyl-terminated butylene succinate oligomers in the present invention has a structural unit as shown in Formula I. Its randomness is 1 as tested by nuclear magnetic resonance hydrogen spectrum analysis. Therefore, the polyester polyol provided by the present invention is a random copolymer.

[0012] Formula I.

[0013] The present invention prepares hydroxyl-terminated butylene succinate oligomers through succinic anhydride. Since succinic anhydride can be obtained by hydrogenating upstream maleic anhydride, it has a cost advantage over dimethyl succinate, thus solving the problem of expensive raw material costs in the ester exchange method.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] Preferably, the molecular weight of the polyester polyol is 0.5-4 kDa (for example, 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.), more preferably 0.5-1 kDa.

[0019] Preferably, the mole percentage of glycolide units in the polyester polyol is 3-80 mol% (for example, 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.), and more preferably 5-40 mol% (for example, 8 mol%, 12 mol%, 14 mol%, 16 mol%, 22 mol%, 24 mol%, 26 mol%, 28 mol%, 32 mol%, 34 mol%, 36 mol%, 38 mol%, etc.).

[0020] Preferably, the molar ratio of the succinic anhydride to the first 1,4-butanediol is 1:(1.1-2), for example, 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.

[0021] Preferably, the temperature of the esterification reaction is 160-200°C, for example, 162°C, 165°C, 168°C, 170°C, 172°C, 175°C, 178°C, 180°C, 182°C, 185°C, 188°C, 190°C, 192°C, 195°C, 198°C, etc.

[0022] 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.

[0023] Preferably, the esterification reaction is carried out in the presence of a first catalyst.

[0024] Preferably, the first catalyst comprises any one or a combination of at least two of tin oxide, zinc dichloride, hydrated zinc sulfate, calcium chloride, copper chloride, aluminum chloride or p-toluenesulfonic acid, more preferably p-toluenesulfonic acid and / or zinc dichloride.

[0025] 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.

[0026] 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.

[0027] Preferably, the temperature of the first prepolymerization reaction is 180-220°C, for example, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, etc.

[0028] Preferably, the first prepolymerization reaction time 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.

[0029] Preferably, the preparation method of the hydroxyl-terminated glycolide oligomer comprises:

[0030] The glycolide and the second 1,4-butanediol undergo a first reaction to obtain the hydroxyl-terminated glycolide oligomer, and the reaction formula is as follows:

[0031] .

[0032] The present invention adopts succinic anhydride, glycolide and 1,4-butanediol as raw materials to prepare polyester polyols. Compared with the method of using succinic acid, glycolic acid and 1,4-butanediol as raw materials for polycondensation to synthesize polyester polyols, the present invention solves the problems of poor atom economy and equipment corrosion in the polycondensation method.

[0033] Preferably, the molar ratio of the glycolide to the 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.

[0034] Preferably, the temperature of the first reaction is 140-240°C, for example, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, etc.

[0035] Preferably, the first reaction time is 10-180 min, for example, 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.

[0036] Preferably, the first reaction is carried out under an inert atmosphere.

[0037] Preferably, the first reaction is carried out in the presence of a second catalyst.

[0038] Preferably, the second catalyst comprises any one or a combination of at least two of bismuth chloride, bismuth oxide, bismuth trifluoromethanesulfonate, 2-ethyl bismuth acetate, stannous octoate, stannous acetate or di-n-octyltin dilaurate, and further preferably any one or a combination of at least two of bismuth chloride, 2-ethyl bismuth acetate or stannous octoate.

[0039] 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.

[0040] Preferably, the ratio of the total mass of the polymerized monomers of the hydroxyl-terminated glycolide oligomer to the total mass of the polymerized 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.

[0041] In a second aspect, the present invention provides a method for preparing the polyester polyol as described in the first aspect, the preparation method comprising:

[0042] After the hydroxyl-terminated glycolide oligomer and the hydroxyl-terminated butylene succinate oligomer are mixed, a second prepolymerization reaction and a second reaction are sequentially performed to obtain the polyester polyol.

[0043] In the preparation method of the polyester polyol provided by the present invention, hydroxyl-terminated glycolide oligomers and hydroxyl-terminated butylene succinate oligomers are first subjected to a prepolymerization reaction, which can solve the problems of pipe blockage and material loss in the preparation process of the polyester polyol.

[0044] Preferably, the temperature of the second prepolymerization reaction is 160-200°C, for example, 162°C, 165°C, 168°C, 170°C, 172°C, 175°C, 178°C, 180°C, 182°C, 185°C, 188°C, 190°C, 192°C, 195°C, 198°C, etc.

[0045] Preferably, the second prepolymerization reaction time is 30-150 min, for example, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, etc.

[0046] 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.

[0047] Preferably, the second prepolymerization reaction is carried out in the presence of a third catalyst and / or a thermal stabilizer.

[0048] Preferably, the third catalyst comprises any one of tetrabutyl titanate, isopropyl titanate or titanium ethylene glycol, or a combination of at least two thereof, and titanium ethylene glycol and / or tetrabutyl titanate are further preferred.

[0049] 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.

[0050] Preferably, the heat stabilizer includes any one of phosphoric acid, trimethyl phosphate or disodium hydrogen phosphate, or a combination of at least two thereof.

[0051] Preferably, based on the mass of the hydroxyl-terminated glycolide oligomer as 100%, the mass of the thermal stabilizer is 2-8 ppm, 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.

[0052] Preferably, the temperature of the second reaction is 210-260°C, for example, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, etc.

[0053] 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.

[0054] Preferably, the time of the second reaction is 1-5 h, for example, 1.2 h, 1.4 h, 1.6 h, 1.8 h, 2 h, 2.2 h, 2.5 h, 2.8 h, 3 h, 3.2 h, 3.5 h, 3.8 h, 4 h, 4.2 h, 4.5 h, 4.8 h, etc.

[0055] In a third aspect, the present invention provides a polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol, aliphatic isocyanate and a chain extender as described in the first aspect.

[0056] The present invention achieves the regulation of the degradation performance and mechanical properties of polyurethane by regulating the structure of polyester polyol. The obtained polyurethane has excellent biocompatibility, blood compatibility, mechanical properties, processing properties, and is non-toxic. It can be processed and formed by injection molding, extrusion, blow molding, etc., and can be used to manufacture medical devices of complex shapes and different sizes, and is easy to process and form. Compared with the degradable materials obtained by biological fermentation, the polyurethane provided by the present invention has obvious cost advantages and good batch stability, can solve the problems of large brittleness, poor processing performance, and high cost of current degradable materials, and has excellent comprehensive performance; and the polyurethane provided by the present invention will not produce local accumulation of acidic products when degraded in the human body, so it will not induce inflammation, reducing the risk of complications in related patients, and can be widely used in the field of medical devices for making in vivo and in vitro degradable medical devices. It can be widely used in the fields of fracture repair, vascular repair, tissue engineering, drug sustained release, biosensors, etc.

[0057] Preferably, the aliphatic isocyanate includes any one of hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate or L-lysine diisocyanate, or a combination of at least two thereof.

[0058] Preferably, the chain extender includes any one of ethylene glycol, propylene glycol, 1,4-butanediol or 1,6-hexanediol, or a combination of at least two thereof.

[0059] 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.

[0060] Preferably, the molar ratio of the chain extender to the polyester polyol is (0.01-15):1, for example, 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.

[0061] Preferably, the mass percentage of the hard segment 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.

[0062] In the present invention, the hard segment refers to the rigid portion in the polyurethane molecular chain, which is composed of structural units formed by the reaction of isocyanate and a chain extender.

[0063] Preferably, the R value of the polyurethane is 1-1.05, for example, it may be 1.01, 1.02, 1.03, 1.04, etc.

[0064] In the present invention, the calculation formula of the R value is: ,in is the molar amount of isocyanate groups, is the molar amount of hydroxyl groups.

[0065] Preferably, the number average molecular weight of the polyurethane is 50-150 kDa, for example, 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.

[0066] In a fourth aspect, the present invention provides a method for preparing the polyurethane according to the third aspect, the preparation method comprising:

[0067] After the polyester polyol and the aliphatic isocyanate undergo a third reaction, a chain extender is added to carry out a fourth reaction to obtain the polyurethane.

[0068] Preferably, the temperature of the third reaction is 70-100°C, for example, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, etc.

[0069] Preferably, the time of 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.

[0070] Preferably, the third reaction is carried out under a nitrogen atmosphere.

[0071] Preferably, the temperature of the fourth reaction is 70-100°C, for example, it can be 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, etc.

[0072] Preferably, the fourth reaction time 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.

[0073] In a fifth aspect, the present invention provides a use of the polyurethane as described in the third aspect in an absorbable hemostatic sponge, an absorbable hernia repair patch, an absorbable interference screw, an absorbable stent, an artificial blood vessel or an absorbable surgical suture.

[0074] Compared with the prior art, the present invention has the following beneficial effects:

[0075] The polyester polyol provided by the present invention solves the problems of poor atom economy and equipment corrosion in the polycondensation method by designing the raw materials for preparation; the polyurethane prepared using the polyester polyol provided by the present invention has excellent mechanical properties, processing properties, and degradability, is non-cytotoxic, and has excellent overall performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of the polyester polyol provided in Example 7;

[0077] Figure 2 This is a partial enlarged view of the hydrogen nuclear magnetic resonance spectrum of the polyester polyol provided in Example 7;

[0078] Figure 3 This is another partially enlarged view of the hydrogen nuclear magnetic resonance spectrum of the polyester polyol provided in Example 7. DETAILED DESCRIPTION

[0079] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0080] Example 1

[0081] 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;

[0082] The preparation method of the polyester polyol comprises:

[0083] 0.5 mol of succinic anhydride and the first 1,4-butanediol were added to a reaction vessel at a molar ratio of 1:1.6, and p-toluenesulfonic acid (0.1% by weight of the succinic anhydride) was added, and an esterification reaction was carried out at 180° C. for 90 minutes; then, at 10 kPa and 200° C., moisture in the system was removed and a first prepolymerization reaction was carried out for 30 minutes to obtain the hydroxyl-terminated butylene succinate oligomer;

[0084] Prior to the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace moisture, volatile gases, and impurities. The reaction vessel was then filled with dry inert gas. Under a dry inert atmosphere, 0.026 mol of glycolide and a second 1,4-butanediol were added to the reaction vessel filled with dry inert gas at a molar ratio of 1:1. Stannous octoate, which was 0.02% by weight of the glycolide, was added as a catalyst. A first reaction was carried out at 160° C. for 120 minutes to obtain the hydroxyl-terminated glycolide oligomer.

[0085] The obtained hydroxyl-terminated glycolide oligomer was added to the obtained hydroxyl-terminated butylene succinate oligomer under a nitrogen atmosphere, and 0.09% of the weight of hydroxyl-terminated butylene succinate oligomer titanium glycolate and 8 ppm of the weight of hydroxyl-terminated glycolide oligomer trimethyl phosphate were added. A second prepolymerization reaction was carried out at 200° C. and 10 kPa for 60 minutes. The temperature was then raised to 220° C., the pressure was maintained at 15 Pa, and a second reaction was carried out for 120 minutes. The polyester polyol was discharged after the acid value, hydroxyl value and water content met the requirements. The ratios of the raw materials are shown in Table 1.

[0086] Examples 2-8

[0087] A polyester polyol and a preparation method thereof, which differ from Example 1 only in the amounts of glycolide, succinic anhydride, and 1,4-butanediol, as shown in Table 1. The remaining raw materials, process parameters, and steps are the same as those in Example 1.

[0088] Example 9

[0089] 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;

[0090] The preparation method of the polyester polyol comprises:

[0091] 0.5 mol of succinic anhydride and the first 1,4-butanediol were added to a reaction vessel at a molar ratio of 1:1.6, and p-toluenesulfonic acid (0.1% by weight of the succinic anhydride) was added, and an esterification reaction was carried out at 160° C. for 120 minutes; then, at 10 kPa and 200° C., moisture in the system was removed and a first prepolymerization reaction was carried out for 30 minutes to obtain the hydroxyl-terminated butylene succinate oligomer;

[0092] Prior to the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace moisture, volatile gases, and impurities. The reaction vessel was then filled with dry inert gas. Under a dry inert atmosphere, 0.026 mol of glycolide and a second 1,4-butanediol were added to the reaction vessel at a molar ratio of 1:1.5. Stannous octoate, which was 0.02% by weight of the glycolide, was added as a catalyst. A first reaction was carried out at 160° C. for 120 minutes to obtain the hydroxyl-terminated glycolide oligomer.

[0093] The obtained hydroxyl-terminated glycolide oligomer was added to the obtained hydroxyl-terminated butylene succinate oligomer under a nitrogen atmosphere, and 0.09% of tetrabutyl titanate by weight of the hydroxyl-terminated butylene succinate oligomer and 8 ppm of phosphoric acid by weight of the hydroxyl-terminated glycolide oligomer were added. A second prepolymerization reaction was carried out at 200° C. and 10 kPa for 60 minutes. The temperature was then raised to 220° C., the pressure was maintained at 15 Pa, and the second reaction was carried out for 120 minutes. The material 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.

[0094] Examples 10-19

[0095] A polyester polyol and a preparation method thereof, which differ from Example 9 only in the preparation process parameters, as shown in Table 2, and the preparation raw materials are the same as those in Example 9.

[0096] Comparative Example 1

[0097] A polyester polyol and a preparation method thereof, the preparation method comprising the following steps:

[0098] (1) Before the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace moisture, volatile gases, and impurities. The reaction vessel was then filled with dry inert gas. Under a dry inert atmosphere, 0.5 mol of succinic anhydride, 0.839 mol of 1,4-butanediol, and 0.026 mol of glycolide were added to the reaction vessel filled with dry inert gas. Toluenesulfonic acid (0.1% by weight of succinic anhydride) was added, and the esterification reaction was carried out at 180°C for 90 minutes.

[0099] (2) After the esterification reaction, 0.2% of the mass of succinic anhydride in titanium glycolate and 15 ppm of the mass of glycolide in trimethyl phosphate were added to the solution. The water in the system was removed and prepolymerization was carried out at 200° C. and a pressure of 10 kPa for 60 minutes. The temperature was further increased to 220° C., the pressure was maintained at 15 Pa, and the reaction was carried out for 120 minutes before discharging the material to obtain the polyester polyol.

[0100] Comparative Example 2

[0101] A polyester polyol and a preparation method thereof, the preparation method comprising the following steps:

[0102] (1) 0.5 mol of succinic anhydride and the first 1,4-butanediol were added to a reaction vessel at a molar ratio of 1:1.6, and p-toluenesulfonic acid (0.1% by weight of succinic anhydride) was added, and the esterification reaction was carried out at 180°C for 90 minutes;

[0103] Before the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace moisture, volatile gases, and impurities. The reaction vessel was then filled with dry inert gas. Under a dry inert atmosphere, 0.026 mol of glycolide and a second 1,4-butanediol were added to the reaction vessel at a molar ratio of 1:1.5. Stannous octoate (0.02% by weight of glycolide) was added as a catalyst. The reaction was carried out at 160°C for 120 minutes to obtain a hydroxyl-terminated glycolide oligomer.

[0104] (2) The hydroxyl-terminated glycolide oligomer is added to the solution after the esterification reaction under a nitrogen atmosphere, and 0.2% of the mass of succinic anhydride titanium glycolate and 8 ppm of the mass of hydroxyl-terminated glycolide oligomer trimethyl phosphate are added. The temperature is further increased to 220° C., the pressure is maintained at 15 Pa, and the reaction is carried out for 120 minutes, and the material is discharged to obtain the polyester polyol.

[0105] Comparative Example 3

[0106] A polyester polyol and a preparation method thereof, the preparation method comprising the following steps:

[0107] The hydroxyl-terminated glycolide oligomer was added to the hydroxyl-terminated butylene succinate oligomer under a nitrogen atmosphere, and 0.09% of the weight of the hydroxyl-terminated butylene succinate oligomer titanium glycolate and 8 ppm of the weight of the hydroxyl-terminated glycolide oligomer trimethyl phosphate were added, and the reaction was carried out at 220° C. and 15 Pa for 120 minutes before discharging the material to obtain the polyester polyol.

[0108] The preparation method of the hydroxyl-terminated glycolide oligomer and the hydroxyl-terminated butylene succinate oligomer is the same as that of Example 8.

[0109] Comparative Example 4

[0110] A polyester polyol and a preparation method thereof, the preparation method comprising the following steps:

[0111] (1) Before the synthesis reaction, the reaction vessel was thoroughly cleaned with acetone and heated under vacuum to completely remove trace 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 the second 1,4-butanediol were added to the reaction vessel filled with dry inert gas at a molar ratio of 1000:1. Stannous octoate (0.02% by weight of glycolide) was added as a catalyst. The first reaction was carried out at 160°C for 120 minutes to obtain a solid hydroxyl-terminated polyglycolide (polymer).

[0112] (2) The hydroxyl-terminated polyglycolide was crushed and added to a hydroxyl-terminated butylene succinate oligomer under a nitrogen atmosphere, and 0.09% of the mass of hydroxyl-terminated butylene succinate oligomer titanium glycol and 8 ppm of the mass of hydroxyl-terminated polyglycolide trimethyl phosphate were added, and a prepolymerization reaction was carried out at 200°C and 10 kPa for 60 minutes; and then the reaction was carried out at 220°C and 15 Pa for 120 minutes;

[0113] The preparation method of the hydroxyl-terminated butylene succinate oligomer is the same as that in Example 1.

[0114] Table 1

[0115]

[0116] Table 2

[0117]

[0118] Characterization of polyester polyols

[0119] (1) Mole percentage of glycolide units in polyester polyols n GL (mol%):

[0120] The molar percentage of glycolide units was calculated according to the H NMR spectrum and Formula 1. Taking the polyester polyol provided in Example 7 as an example, its H NMR spectrum is as follows: Figure 1 As shown, the chemical shifts 4.63-4.82 ppm are the methylene peaks of the glycolide unit, 4.12-4.20 ppm are the methylene peaks of the 1,4-butanediol unit, and 2.62-2.80 ppm are the methylene peaks of the succinic anhydride unit. Figure 2-3 This is a partial enlarged view of the nuclear magnetic resonance hydrogen spectrum of the polyester polyol provided in Example 7. Figure 2-3The molar percentage of glycolide units was calculated using the following formula: (Formula 1);

[0121] Among them, I g is the sum of the peak areas of g1, g2, g3, and g4, I s It is the sum of the peak areas of s1, s2 (3 peaks in total), s3 (3 peaks in total), and s4.

[0122] (2) Water content of polyester polyols: Determined according to GB / T 22313-2008 Plastics - Determination of water content of polyols used in polyurethane production.

[0123] (3) Acid value: Determined according to HG / T 2708-1995 Determination of acid value in polyester polyols.

[0124] (4) Hydroxyl value: Determined according to HG / T 2709-2022 Plastics - Determination of hydroxyl value of polyester polyols used in the production of polyurethane.

[0125] (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 standards.

[0126] 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 test-related data.

[0127] Table 3

[0128]

[0129] The test data in Table 3 show that 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 <1.5 mgKOH / g, a hydroxyl value of 119.2-205.3 mgKOH / g, and a molecular weight of 0.55-1 kDa.

[0130] In Comparative Example 1, the polyester polyol synthesized using a one-pot process had high water content and acid value, failing to meet the requirements for synthesizing biodegradable polyurethane. In Comparative Example 2, high-vacuum polycondensation was performed directly after esterification, resulting in a large amount of oligomers being extracted from the system, resulting in low raw material utilization and pipeline blockage, leading to synthesis failure. In Comparative Example 3, the hydroxyl-terminated glycolide oligomers and hydroxyl-terminated butylene succinate oligomers were not subjected to a second prepolymerization reaction. During the second reaction, due to the low molecular weight of the hydroxyl-terminated glycolide oligomers, a bumping phenomenon occurred, resulting in a large amount of hydroxyl-terminated glycolide oligomers being extracted. The ratio of succinic anhydride to glycolide in the polyester polyol deviated significantly from the designed value, making it impossible to synthesize the desired polyester polyol ratio and resulting in synthesis failure. In Comparative Example 4, the molar ratio of glycolide to the second 1,4-butanediol was too high. As the reaction progressed, the molecular weight continued to increase, 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 and remained solid, preventing the successful synthesis of the polyester polyol.

[0131] Application Example 1

[0132] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 1, isophorone diisocyanate and 1,4-butanediol;

[0133] The preparation method of the polyurethane comprises:

[0134] Under nitrogen protection, 64.1 g of the polyester polyol provided in Example 1 and 50 g of isophorone diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0135] Application Example 2

[0136] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 2, hexamethylene diisocyanate, and 1,4-butanediol;

[0137] Under nitrogen protection, 68.7 g of the polyester polyol provided in Example 2 and 50 g of hexamethylene diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0138] Application Example 3

[0139] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 3, dicyclohexylmethane diisocyanate, and 1,4-butanediol;

[0140] Under nitrogen protection, 60.4 g of the polyester polyol provided in Example 3 and 50 g of dicyclohexylmethane diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0141] Application Example 4

[0142] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 4, L-lysine diisocyanate, and 1,4-butanediol;

[0143] Under nitrogen protection, 61.6 g of the polyester polyol provided in Example 4 and 50 g of L-lysine diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0144] Application Example 5

[0145] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 5, hexamethylene diisocyanate, and 1,4-butanediol;

[0146] Under nitrogen protection, 67.8 g of the polyester polyol provided in Example 5 and 50 g of hexamethylene diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0147] Application Example 6

[0148] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 6, hexamethylene diisocyanate, and 1,4-butanediol;

[0149] Under nitrogen protection, 68.7 g of the polyester polyol provided in Example 6 and 50 g of hexamethylene diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0150] Application Example 7

[0151] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 7, hexamethylene diisocyanate, and 1,4-butanediol;

[0152] Under nitrogen protection, 68.5 g of the polyester polyol provided in Example 7 and 50 g of hexamethylene diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0153] Application Example 8

[0154] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 8, hexamethylene diisocyanate, and 1,4-butanediol;

[0155] Under nitrogen protection, 66.1 g of the polyester polyol provided in Example 8 and 50 g of hexamethylene diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0156] Application Example 9

[0157] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 1, hexamethylene diisocyanate and 1,4-butanediol;

[0158] Under nitrogen protection, 220.6 g of the polyester polyol provided in Example 1 and 50 g of hexamethylene diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0159] Application Example 10

[0160] A polyurethane, wherein the raw materials for preparing the polyurethane include the polyester polyol provided in Example 1, hexamethylene diisocyanate and 1,4-butanediol;

[0161] Under nitrogen protection, 18.6 g of the polyester polyol provided in Example 1 and 50 g of hexamethylene diisocyanate were added to a reaction vessel and reacted at 70° C. for 120 min. 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.

[0162] Product Characterization and Performance Testing

[0163] (1) Hard segment content: ×100%;

[0164] (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 standards.

[0165] (3) Elongation at break and tensile strength: Determined according to GB / T 1040 Determination of tensile properties of plastics.

[0166] (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, held for 1 minute, to eliminate thermal history. The sample was then cooled to −60°C at a rate of 10°C / min and held for 1 minute. Finally, the sample was heated again to 165°C at a rate of 10°C / min.

[0167] (5) Thermal decomposition temperature T d,5% : Thermogravimetric analysis was performed using a Netzsch TG 209 F3 Tarsus under a nitrogen atmosphere at a heating rate of 10°C / min from 40°C to 700°C.

[0168] (6) Cytotoxicity: The test was performed according to the in vitro cytotoxicity test (MTT cytotoxicity test) in GB / T 16886.5-2017. When the viable cell survival rate dropped to <70% of the blank, the test was considered to have potential cytotoxicity and the cytotoxicity was defined as poor. When the viable cell survival rate was ≥70% of the blank, the test was considered to have excellent cytotoxicity.

[0169] The polyurethanes provided in Application Examples 1-10 were tested according to the above method. The test results are shown in Table 4. The data of PLA, PGA, PCL, PPDO, and PHA in Table 4 are data disclosed in the prior art. The relevant data of PLA comes from: Mehta, R. et al. Synthesis of Poly(Lactic Acid): A Review[J]. Journal ofMacromolecular Science Part C, 2005, 45(5): 325-349. The relevant data of PGA comes from: Middleton, JC. et al . Synthetic biodegradable polymers as orthopedic devices[J]. Biomaterials, 2000,21(23): 2335-2346. The relevant data of PCL comes 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 of PPDO comes from: Yuan, Y. et al. Influencesof 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. The relevant data of PHA comes from: Zhang Xiangnan. Study on the properties of poly 3-hydroxybutyrate and 4-hydroxybutyrate[J]. Plastics Science and Technology, 2011, 39(05):57-62. The biocompatibility data of PLA, PHA and PCL comes from: Mi, CH. et al. Advances inmedical polyesters for vascular tissue engineering[J].Discover Nano, 2024, 19, 125. The biocompatibility data of PPDO is from: Lu J. L, et al. 3D-Printed Poly (P-Dioxanone) Stent for Endovascular Application: In Vitro Evaluations[J]. Polymers, 2022, 14(9): 1755. The biocompatibility data of PGA is from: Fu S. J, et al. Surface Coating Modified Polyglycolide (PGA) Braided Threads as Potential Thread-embedding Materials[J]. Fibers Polym, 2020, 21, 2401-2406.

[0170] Table 4

[0171]

[0172] As shown in Table 4, the polyurethane provided by the present invention has 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 has excellent biocompatibility. Compared with PGA and PPDO, the polyurethane provided by the present invention has a higher decomposition temperature (T d,5% >250°C), with a significant difference between its melting point and decomposition temperature, offering excellent processing properties. Compared to PLA, PGA, and PHA, the polyurethane provided by this invention has superior toughness; compared to PCL, it has higher tensile strength.

[0173] (7) Mass loss rate test: After the polyurethane is melted, it is hot-pressed into a film using a mold at 150°C and 5 MPa, and then sliced (1×2 cm, thickness 0.8 mm). It is placed in a vacuum oven at 40°C and dried to constant weight, and its initial mass M0 is weighed; then the polyurethane slices are placed in a phosphate buffer solution (pH 7.4) at 37°C for in vitro degradation experiments. After the predetermined degradation time, the filter is obtained, and the filter is rinsed three times with secondary analytical water that complies with GB / T 6682, and dried to constant weight at room temperature under vacuum, and its mass M is weighed. t The mass loss rate during the degradation process was calculated according to the following formula. The greater the mass loss rate, the stronger the degradation ability. The test results are shown in Table 5.

[0174] Mass loss rate = (M0-M t ) / M0×100%;

[0175] Where: M0 represents the initial mass; M t Indicates the mass of the filtrate at day t;

[0176] Table 5

[0177]

[0178] The degradation capacity of polyurethane can be regulated by the proportion of glycolide units in the polyester polyol chain segment. In vitro degradation experiments in Application Examples 5-8 showed that increasing the glycolide unit content improved the degradation capacity of the polyurethane. Application Examples 1-4 used different diisocyanates to synthesize polyurethanes. Different diisocyanates affect the regularity of the polyurethane molecular chain. Because hexamethylene diisocyanate is more regular, the polyurethanes obtained using it as a raw material have high crystallinity and weaker degradation capacity. Application Examples 9 and 10 present polyurethanes with different hard segment contents. As the hard segment content increases, the degradation capacity of the polyurethane decreases.

[0179] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the polyester polyols, their preparation methods, and applications. However, the present invention is not limited to these embodiments, and it does not necessarily rely on these embodiments for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for raw materials in the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A polyester polyol, characterized in that The raw materials for preparing the polyester polyol include hydroxyl-terminated glycolide oligomer and hydroxyl-terminated butylene succinate oligomer; The preparation method of the hydroxyl-terminated butylene succinate oligomer comprises: Succinic anhydride and the first 1,4-butanediol are mixed and sequentially subjected to an esterification reaction and a first prepolymerization reaction to obtain the hydroxyl-terminated butylene succinate oligomer; The pressure of the first prepolymerization reaction is 5-20 kPa; The preparation method of the hydroxyl-terminated glycolide oligomer comprises: The glycolide and the second 1,4-butanediol are subjected to a first reaction to obtain the hydroxyl-terminated glycolide oligomer; The preparation method of the polyester polyol comprises: After the hydroxyl-terminated glycolide oligomer and the hydroxyl-terminated butylene succinate oligomer are mixed, a second prepolymerization reaction and a second reaction are sequentially performed to obtain the polyester polyol.

2. The polyester polyol according to claim 1, wherein The water content of the polyester polyol is ≤0.02%; The acid value of the polyester polyol is 1-1.5 mgKOH / g; The polyester polyol has a hydroxyl value of 100-250 mgKOH / g; The molecular weight of the polyester polyol is 0.5-4 kDa; In the polyester polyol, the molar percentage of the glycolide unit is 3-80 mol%, based on the total molar percentage of the succinic anhydride-based unit and the glycolide unit being 100 mol%.

3. The polyester polyol according to claim 1, wherein The molar ratio of the succinic anhydride to the first 1,4-butanediol is 1:(1.1-2); The temperature of the esterification reaction is 160-200°C; The esterification reaction time is 60-120min; 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, hydrated zinc sulfate, calcium chloride, copper chloride, aluminum chloride or p-toluenesulfonic acid; Based on the mass of the succinic anhydride as 100%, the mass of the first catalyst is 0.01-0.2%; The temperature of the first prepolymerization reaction is 180-220°C; The first prepolymerization reaction time is 10-40 minutes.

4. The polyester polyol according to claim 1, wherein The molar ratio of the glycolide to the second 1,4-butanediol is 1:(1-3); The temperature of the first reaction is 140-240°C; The time of the first reaction is 10-180min; The first reaction is carried out under an inert atmosphere; The first reaction is carried out in the presence of a second catalyst; 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; Based on the mass of the glycolide being 100%, the mass of the second catalyst is 0.01-0.035%.

5. A method for preparing a polyester polyol according to any one of claims 1 to 4, characterized in that: The preparation method comprises: After the hydroxyl-terminated glycolide oligomer and the hydroxyl-terminated butylene succinate oligomer are mixed, a second prepolymerization reaction and a second reaction are sequentially performed to obtain the polyester polyol.

6. The preparation method according to claim 5, characterized in that The temperature of the second prepolymerization reaction is 160-200°C; The second prepolymerization reaction time is 30-150min; 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 thermal stabilizer; The third catalyst comprises any one of tetrabutyl titanate, isopropyl titanate or titanium ethylene glycol, or a combination of at least two thereof; 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 of phosphoric acid, trimethyl phosphate or disodium hydrogen phosphate or a combination of at least two thereof; Based on the mass of the hydroxyl-terminated glycolide oligomer being 100%, the mass of the thermal stabilizer is 2-8 ppm; The temperature of the second reaction is 210-260°C; The pressure of the second reaction is 15-30Pa; The second reaction time is 1-5 hours.

7. A polyurethane, characterized in that The raw materials for preparing the polyurethane include the polyester polyol according to any one of claims 1 to 4, an aliphatic isocyanate and a chain extender.

8. The polyurethane according to claim 7, characterized in that The aliphatic isocyanate includes any one of hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate or L-lysine diisocyanate, or a combination of at least two thereof; The chain extender includes any one of ethylene glycol, propylene glycol, 1,4-butanediol or 1,6-hexanediol or a combination of at least two thereof; The molar ratio of the polyester polyol to the aliphatic isocyanate is 1:(1.1-17); The molar ratio of the chain extender to the polyester polyol is (0.01-15):

1.

9. The polyurethane according to claim 7, 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.

10. A method for preparing the polyurethane according to any one of claims 7 to 9, characterized in that: The preparation method comprises: After the polyester polyol and the aliphatic isocyanate undergo a third reaction, a chain extender is added to carry out a fourth reaction to obtain the polyurethane.

11. The preparation method according to claim 10, characterized in that: The temperature of the third reaction is 70-100°C; The time of the third reaction is 120-240min; The temperature of the fourth reaction is 70-100°C; The fourth reaction time is 60-240 min.

12. Use of the polyurethane according to any one of claims 7 to 9 in the preparation of an absorbable hemostatic sponge, an absorbable hernia repair patch, an absorbable interference screw, an absorbable stent, an artificial blood vessel or an absorbable surgical suture.

Images