A medical absorbent and breathable polyurethane foam material and a method for preparing the same
By modifying the material with nano-hydroxyapatite and mesoporous silica nanospheres, a multi-level breathable pore network was constructed, which solved the contradiction between water absorption and breathability of medical polyurethane foam materials, achieving a balance between high water absorption and high breathability, and meeting the needs of high-end nursing care.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG SHUERKANG BIOTECHNOLOGY CO LTD
- Filing Date
- 2026-03-06
- Publication Date
- 2026-05-29
AI Technical Summary
Existing medical polyurethane foam materials present a contradiction in terms of water absorption and breathability, making it difficult to simultaneously meet the needs of high-end care and special wounds. Increased hydrophilicity leads to a decrease in breathability.
By modifying nano-hydroxyapatite and mesoporous silica nanospheres, and reacting them with polyurethane prepolymer through surface hydrophilization treatment, a multi-level breathable pore network is constructed. The pore structure is regulated by silicone stabilizer, and combined with SAP to form a water absorption synergistic effect.
It significantly improves the water absorption and breathability of the material, achieving a balance between high water absorption and high breathability, resolving the contradiction between hydrophilicity and breathability, and meeting the needs of high-end care.
Smart Images
Figure CN122103665A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of medical materials technology, specifically to a medical absorbent and breathable polyurethane foam material and its preparation method. Background Technology
[0002] Medical foam materials are essential functional materials in wound care and medical protection. Their water absorption and breathability directly affect the nursing effect, patient comfort, and wound recovery process. Polyurethane foam materials, due to their excellent biocompatibility, flexibility, mechanical stability, and processing plasticity, meet the basic safety requirements of medical materials and are widely used in chronic wound care, postoperative incision protection, and wound dressings, becoming the mainstream category in the medical foam material field. Currently, medical polyurethane foam materials are mostly made from polyether polyols and isocyanates as the main raw materials, supplemented with foaming agents, catalysts, crosslinking agents, and other additives, and formed through one-step foaming or stepwise polymerization processes. With the increasing sophistication of clinical nursing needs, the limitations of existing medical polyurethane foam materials in terms of water absorption and breathability are becoming increasingly prominent. Although existing modification technologies have improved the hydrophilicity of polyurethane foam to some extent, the contradiction between hydrophilicity and breathability is difficult to balance. Increasing hydrophilicity often leads to denser cell structures and a significant decrease in breathability, making it difficult to meet the needs of high-end care and special wounds, becoming a key bottleneck restricting its application expansion. Summary of the Invention
[0003] The purpose of this invention is to provide a medical-grade absorbent and breathable polyurethane foam material and its preparation method, thereby solving the technical problems mentioned in the background section. The polyurethane foam material prepared by this invention possesses both excellent absorbent and breathable properties.
[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a medical absorbent and breathable polyurethane foam material includes the following steps: (1) After dehydrating polyethylene glycol, EO-terminated polypropylene glycol and side-chain hydrophilic diol, it is reacted with HDI trimer and organic bismuth catalyst to obtain the basic prepolymer; (2) After the nano-hydroxyapatite is modified with polyethylene glycol silane, it is mixed and dispersed with acetyl tributyl citrate, and then added to the basic prepolymer to react and obtain a water-absorbing modified prepolymer. (3) After the mesoporous silica nanospheres are modified with polyethylene glycol silane, they are mixed and dispersed with acetyl tributyl citrate, silicone foam stabilizer, organobismuth / organozinc composite catalyst and dimethyl silicone oil, and then added to the water-absorbing modified prepolymer to react and obtain the double-modified polyurethane mother liquor. (4) Mix the double-modified polyurethane mother liquor with medical grade SAP, then add an aqueous phase consisting of water, 1,4-butanediol and amine catalyst, stir at high speed and inject into a mold, and after curing and drying, obtain medical water-absorbing and breathable polyurethane foam material.
[0005] In the technical solution of this invention, the principle for improving the water absorption performance of polyurethane foam materials is as follows: Using nano-hydroxyapatite as the core modified filler, its surface is first modified by medical-grade polyethylene glycol silane in a slightly acidic ethanol / water system. The hydrophilic polyether segments are anchored to the surface of the nanoparticles via silane hydrolysis and condensation, solving the agglomeration problem of nano-hydroxyapatite and introducing pure hydroxyl sites that can react with the polyurethane prepolymer. Then, using inert and non-toxic tributyl citrate as the physical suspension medium, a uniformly dispersed precursor slurry without phase separation is prepared through high-shear dispersion, avoiding agglomeration of nanoparticles directly added to the prepolymer, which would lead to uneven distribution of hydrophilic sites. Finally, the precursor slurry is reacted with the basic prepolymer at a constant temperature, allowing the polyether hydroxyl groups on the surface of the nanoparticles to... Stable micrografting with the -NCO group of the prepolymer allows hydrophilic nano-hydroxyapatite to be uniformly embedded in the three-dimensional framework of polyurethane, introducing a large number of hydrophilic groups into the matrix at the molecular level. At the same time, the physical dilution effect of acetyltributyl citrate ensures the stability of the prepolymer viscosity without damaging the structural integrity of the polyurethane framework, and also creates good rheological conditions for subsequent foaming processes. The dual hydrophilic system of hydrophilic groups in the polyurethane framework and hydrophilic micro / nano structures constructed by this modification process can also form a synergistic water absorption effect with the large-particle medical-grade SAP embedded in the cell walls in the subsequent foaming steps. When the dressing comes into contact with wound exudate, the hydrophilic framework can quickly guide the liquid to contact the SAP in the cell walls and activate its high water absorption performance, thereby significantly improving the water absorption rate of the foam material.
[0006] The principle for improving the air permeability of polyurethane foam materials is as follows: Using mesoporous silica nanospheres as the core pore support filler, the surface of the nanospheres is first modified with polyethylene glycol silane in a weakly acidic isopropanol / water system. This process retains the high thermal stability of the mesoporous silica inorganic material while introducing hydrophilic polyether segments, improving its compatibility with the polyurethane organic matrix and preventing pore thermal collapse during subsequent high-temperature foaming, thus preserving a stable mesoporous foundation for the air permeable structure. Then, the modified mesoporous microspheres are dispersed together with a silicone foam stabilizer and an organobismuth / organozinc composite catalyst in anhydrous tributyl citrate oil phase to prepare a precursor slurry. The isolation and protection effect of the anhydrous oil phase solves the problems of easy hydrolysis of the silicone stabilizer and easy deactivation of the metal catalyst, ensuring the foaming activity of the additives. Then… The slurry reacts with the water-absorbing modified prepolymer at a constant temperature, enabling uniform chemical anchoring of the mesoporous microspheres to the polyurethane skeleton. Simultaneously, the silicone stabilizer and composite catalyst are uniformly dissolved throughout the mother liquor. During the subsequent foaming process, the pre-embedded silicone foam stabilizer precisely controls the size, uniformity, and connectivity of the cells. The inherent mesoporous structure of the mesoporous microspheres and the macroporous structure generated by the foaming reaction are interconnected, constructing a stable macroporous-mesoporous multi-level permeable pore network. Furthermore, the organobismuth / organozinc composite catalyst and the subsequently added trace amounts of amine catalyst form a synergistic catalytic system, ensuring the matching of the foaming and gelation reaction rates and avoiding problems such as cell closure and collapse. Ultimately, a structurally complete and interconnected multi-level permeable pore system is formed, significantly improving the gas exchange efficiency of the polyurethane foam material and achieving a remarkable improvement in permeability.
[0007] Preferably, in step (1), the mass ratio of polyethylene glycol, EO-terminated polypropylene glycol, and side-chain hydrophilic diol is 8:(0.8-1.2):(1.0-1.5).
[0008] In the experiment, the present invention found that the water-absorbing modified prepolymer generated in step (2) and the low surface energy hydrophobic silicone stabilizer introduced in step (3) have severe thermodynamic repulsion, which causes the hydrophobic silicone stabilizer to be violently squeezed to the surface interface by the matrix. It not only tightly blocks the air channels of pure mesoporous silica microspheres like plastic wrap, but also greatly increases the toughness of the foam window film, causing severe macroscopic closure and volume shrinkage, which affects the improvement of the air permeability of polyurethane foam material. To address the technical challenges, this invention introduces EO-terminated polypropylene glycol (PPG) to replace a portion of polyethylene glycol (PEG) during the preparation of the basic prepolymer. Utilizing its terminal primary hydroxyl groups to ensure homogeneous copolymerization kinetics, and leveraging the moderate hydrophobicity of its main chain, it breaks the extremely strong hydrogen bond network of pure PEG at the molecular level, chemically weakening the toughness of the foam window membrane. Simultaneously, a trace amount of pure dimethyl silicone oil (extremely low viscosity, non-surfactant) is precisely embedded in the breathable modified anhydrous slurry. This inert pure silicone oil disperses into nano-sized droplets under high shear, precisely dispersing at the critical point of the foaming gel to the weakest point of the PPG-weakened window membrane. Utilizing the extreme surface tension difference as a "nanosurgical scalpel," it instantly physically punctures the window membrane. This microscopic synergistic mechanism, without altering the system's stoichiometry or operating temperature, perfectly resolves the polar repulsion conflict between hydrophilic and hydrophobic elements, completely opening up the multi-level breathable network of macropores and mesopores. This ensures that the material maintains ultra-high water absorption while completely solving closed-cell shrinkage, further enhancing breathability.
[0009] Preferably, in step (1), the mass ratio of polyethylene glycol to HDI trimer is 8:(7-8).
[0010] Preferably, in step (2), the mass ratio of nano-hydroxyapatite to polyethylene glycol silane is 2.5:(1.0-1.5).
[0011] Preferably, in step (2), the mass ratio of nano-hydroxyapatite to acetylated tributyl citrate is 2.5:(8-12).
[0012] Preferably, in step (3), the mass ratio of mesoporous silica nanospheres to polyethylene glycol silane is 3.5:(1-2).
[0013] Preferably, in step (4), the mass ratio of the dual-modified polyurethane mother liquor to the medical-grade SAP is 160:(4-8).
[0014] A medical absorbent and breathable polyurethane foam material is prepared by the method described above.
[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. By constructing a dual water absorption system of hydrophilic framework grafting and nanoparticle hydrophilic modification, and forming a synergistic effect with SAP, the material's ability to absorb wound exudate is significantly improved.
[0016] 2. By using mesoporous silica to construct thermally stable multi-level permeable channels and combining it with silicone stabilizers to regulate the pore structure, the gas exchange efficiency is greatly improved.
[0017] 3. By employing a synergistic mechanism of chemically weakening the toughness of the window film and physically puncturing the closed pores, the polar repulsion between the hydrophilic matrix and the hydrophobic additives is resolved, fundamentally eliminating closed-pore shrinkage and achieving high water absorption and high air permeability. Attached Figure Description
[0018] Figure 1 This is a low-magnification SEM image of the medical absorbent and breathable polyurethane foam material prepared in Example 1 of the present invention.
[0019] Figure 2 This is a medium-magnification SEM image of the medical absorbent and breathable polyurethane foam material prepared in Example 1 of the present invention.
[0020] Figure 3 This is a high-magnification SEM image of the medical absorbent and breathable polyurethane foam material prepared in Example 1 of the present invention.
[0021] Figure 4 XPS spectrum of the medical absorbent and breathable polyurethane foam material prepared in Example 1 of this invention.
[0022] Figure 5 The image shows the XRD pattern of the medical absorbent and breathable polyurethane foam material prepared in Example 1 of this invention. Detailed Implementation
[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0024] Example 1 A method for preparing a medical absorbent and breathable polyurethane foam material includes the following steps: Step 1: Weigh 80g of medical-grade polyethylene glycol (molecular weight approximately 2000), 11g of medical-grade EO-terminated polypropylene glycol (molecular weight approximately 2000), and 14g of side-chain hydrophilic diol (Ymer N120) and place them in a vacuum drying oven. Dehydrate under vacuum at 105℃ for 2.5h. After dehydration, cool to 45℃ and transfer to a three-necked flask. Accurately add 77g of medical-grade HDI trimer and dropwise add 0.15g of medical-grade organic bismuth catalyst. Purge with high-purity nitrogen for continuous protection. Adjust the mechanical stirring speed to 350r / min. First, raise the temperature to 65℃ and react at a constant temperature for 1.5h. Then, raise the temperature to 85℃ and continue reacting at a constant temperature for 3h. After the reaction is complete, cool to 60℃ for later use to obtain the basic prepolymer.
[0025] Step 2: Weigh 2.5g of nano-hydroxyapatite and add it to 50mL of ethanol / water mixture (volume ratio 95:5, pH adjusted to 4.5 with glacial acetic acid). Disperse the mixture ultrasonically at 350W for 35min. Then add 1.4g of medical-grade polyethylene glycol silane. Place the system in a 60℃ water bath and stir for 2h. After the reaction, centrifuge the product three times and wash it with anhydrous ethanol. Dry the product in an 80℃ vacuum drying oven for 12h to obtain surface-modified nano-hydroxyapatite powder. Measure 11g of vacuum-dehydrated acetylated tributyl citrate and keep it at 60℃. Add all the modified nano-hydroxyapatite dry powder prepared above and disperse it at a high speed of 2500r / min for 15min using a high-shear disperser to obtain a precursor slurry. Add all of the precursor slurry to the above-mentioned basic prepolymer, which is kept at 60℃. Adjust the stirring speed to 550r / min and stir the reaction at a constant temperature for 3h. After the reaction is completed, cool it down to 45℃ for later use to obtain the water-absorbing modified prepolymer.
[0026] Step 3: Weigh 3.5g of pure mesoporous silica nanospheres and add them to 50mL of isopropanol / water mixed buffer (volume ratio 95:5, pH adjusted to 5.5), and sonicate for 28min; add 1.8g of medical-grade polyethylene glycol silane, stir and react in a 40℃ constant temperature water bath for 1h, centrifuge and wash 3 times after reaction, and vacuum dry at 55℃ for 12h to obtain surface-modified mesoporous silica nanosphere powder; measure 8g of acetyltributyl citrate, and add 3.5g of silicone foam stabilizer and 0.5g of organobismuth / organozinc composite to it in sequence. The catalyst (mass ratio 1:1) and 0.1g of pure dimethyl silicone oil (extremely low viscosity 100cSt) were mixed evenly and then all the surface-modified mesoporous silica nanospheres prepared above were added. The mixture was dispersed for 15 minutes at a speed of 2500r / min using a high-shear disperser to obtain a breathable modified slurry. The slurry was then added to the above water-absorbing modified prepolymer which was kept at a constant temperature of 45℃. The stirring speed was adjusted to 450r / min, and the reaction was continued at a constant temperature for 1.5h. After the reaction was completed, the system temperature was kept at a constant temperature of 45℃ to obtain a double-modified polyurethane mother liquor.
[0027] Step 4: Measure 160g of the double-modified polyurethane stock solution maintained at 45℃ and place it in a foaming cup. Add 7.0g of absolutely dry medical-grade SAP (particle size distribution 150-300μm) and stir at 500r / min for 15s to suspend it uniformly. In another container, prepare the aqueous phase by mixing 1.5g of deionized water, 1.5g of chain extender 1,4-butanediol, and 0.1g of trace amine catalyst and maintaining the mixture at room temperature. Quickly inject this aqueous phase into the foaming cup. The mother liquor of SAP was immediately started and foaming machine was turned on to perform high-speed and strong shearing and stirring at a speed of 1800 r / min, with the stirring time precisely controlled to 8 seconds. Then, the mixed slurry was quickly poured into an aviation aluminum mold that was preheated to 65°C and sprayed with Teflon release agent. It was first initially cured at 65°C for 1.2 hours, and then heated to 75°C for constant temperature curing for 2.5 hours. After curing, the mold was demolded and the foam was placed in an empty drying oven at 60°C for 5 hours to obtain medical water-absorbing and breathable polyurethane foam material.
[0028] Example 2 A method for preparing a medical absorbent and breathable polyurethane foam material includes the following steps: Step 1: Weigh 80g of medical-grade polyethylene glycol (molecular weight approximately 2000), 9g of medical-grade EO-terminated polypropylene glycol (molecular weight approximately 2000), and 12g of side-chain hydrophilic diol (Ymer N120) and place them in a vacuum drying oven. Dehydrate under vacuum at 105℃ for 2.5h. After dehydration, cool to 45℃ and transfer to a three-necked flask. Accurately add 72g of medical-grade HDI trimer and dropwise add 0.15g of medical-grade organic bismuth catalyst. Purge with high-purity nitrogen for continuous protection. Adjust the mechanical stirring speed to 350r / min, first raise the temperature to 65℃ and react at a constant temperature for 1.5h, then raise the temperature to 85℃ and continue reacting at a constant temperature for 3h. After the reaction is complete, cool to 60℃ for later use to obtain the basic prepolymer.
[0029] Step 2: Weigh 2.5g of nano-hydroxyapatite and add it to 50mL of ethanol / water mixture (volume ratio 95:5, pH adjusted to 4.5 with glacial acetic acid). Disperse the mixture ultrasonically at 350W for 35min. Then add 1.1g of medical-grade polyethylene glycol silane. Place the system in a 60℃ water bath and stir for 2h. After the reaction, centrifuge the product three times and wash it with anhydrous ethanol. Dry the product in an 80℃ vacuum drying oven for 12h to obtain surface-modified nano-hydroxyapatite powder. Measure 9g of vacuum-dehydrated acetylated tributyl citrate and keep it at 60℃. Add all the modified nano-hydroxyapatite dry powder prepared above and disperse it at a high speed of 2500r / min for 15min using a high-shear disperser to obtain a precursor slurry. Add all of the precursor slurry to the above-mentioned basic prepolymer, which is kept at 60℃. Adjust the stirring speed to 550r / min and stir the reaction at a constant temperature for 3h. After the reaction is completed, cool it down to 45℃ for later use to obtain the water-absorbing modified prepolymer.
[0030] Step 3: Weigh 3.5g of pure mesoporous silica nanospheres and add them to 50mL of isopropanol / water mixed buffer (volume ratio 95:5, pH adjusted to 5.5), and sonicate for 28min; add 1.2g of medical-grade polyethylene glycol silane, stir and react in a 40℃ constant temperature water bath for 1h, centrifuge and wash 3 times after reaction, and vacuum dry at 55℃ for 12h to obtain surface-modified mesoporous silica nanosphere powder; measure 8g of acetyltributyl citrate, and add 3.5g of silicone foam stabilizer and 0.5g of organobismuth / organozinc composite to it in sequence. The catalyst (mass ratio 1:1) and 0.1g of pure dimethyl silicone oil (extremely low viscosity 100cSt) were mixed evenly and then all the surface-modified mesoporous silica nanospheres prepared above were added. The mixture was dispersed for 15 minutes at a speed of 2500r / min using a high-shear disperser to obtain a breathable modified slurry. The slurry was then added to the above water-absorbing modified prepolymer which was kept at a constant temperature of 45℃. The stirring speed was adjusted to 450r / min, and the reaction was continued at a constant temperature for 1.5h. After the reaction was completed, the system temperature was kept at a constant temperature of 45℃ to obtain a double-modified polyurethane mother liquor.
[0031] Step 4: Measure 160g of the double-modified polyurethane mother liquor maintained at 45℃ and place it in a foaming cup. Add 5.0g of absolutely dry medical-grade SAP (particle size distribution 150-300μm) and stir at 500r / min for 15s to suspend it uniformly. In another container, prepare the aqueous phase component by mixing 1.5g of deionized water, 1.5g of chain extender 1,4-butanediol, and 0.1g of trace amine catalyst evenly and maintaining it at room temperature. Quickly inject this aqueous phase component into the foaming cup. The mother liquor of SAP was immediately started and foaming machine was turned on to perform high-speed and strong shearing and stirring at a speed of 1800 r / min, with the stirring time precisely controlled to 8 seconds. Then, the mixed slurry was quickly poured into an aviation aluminum mold that was preheated to 65°C and sprayed with Teflon release agent. It was first initially cured at 65°C for 1.2 hours, and then heated to 75°C for constant temperature curing for 2.5 hours. After curing, the mold was demolded and the foam was placed in an empty drying oven at 60°C for 5 hours to obtain medical water-absorbing and breathable polyurethane foam material.
[0032] Example 3 A method for preparing a medical absorbent and breathable polyurethane foam material includes the following steps: Step 1: Weigh 80g of medical-grade polyethylene glycol (molecular weight approximately 2000), 10g of medical-grade EO-terminated polypropylene glycol (molecular weight approximately 2000), and 13g of side-chain hydrophilic diol (Ymer N120) and place them in a vacuum drying oven. Dehydrate under vacuum at 105℃ for 2.5h. After dehydration, cool to 45℃ and transfer to a three-necked flask. Accurately add 75g of medical-grade HDI trimer and dropwise add 0.15g of medical-grade organic bismuth catalyst. Purge with high-purity nitrogen for continuous protection. Adjust the mechanical stirring speed to 350r / min. First, raise the temperature to 65℃ and react at a constant temperature for 1.5h. Then, raise the temperature to 85℃ and continue reacting at a constant temperature for 3h. After the reaction, cool to 60℃ for later use to obtain the basic prepolymer.
[0033] Step 2: Weigh 2.5g of nano-hydroxyapatite and add it to 50mL of ethanol / water mixture (volume ratio 95:5, pH adjusted to 4.5 with glacial acetic acid). Disperse the mixture ultrasonically at 350W for 35min. Then add 1.2g of medical-grade polyethylene glycol silane. Place the system in a 60℃ water bath and stir for 2h. After the reaction, centrifuge the product three times and wash it with anhydrous ethanol. Dry the product in an 80℃ vacuum drying oven for 12h to obtain surface-modified nano-hydroxyapatite powder. Measure 10g of vacuum-dehydrated acetylated tributyl citrate and keep it at 60℃. Add all the modified nano-hydroxyapatite dry powder prepared above and disperse it at a high speed of 2500r / min for 15min using a high-shear disperser to obtain a precursor slurry. Add all of the precursor slurry to the above-mentioned basic prepolymer, which is kept at 60℃. Adjust the stirring speed to 550r / min and stir the reaction at a constant temperature for 3h. After the reaction is completed, cool it down to 45℃ for later use to obtain the water-absorbing modified prepolymer.
[0034] Step 3: Weigh 3.5g of pure mesoporous silica nanospheres and add them to 50mL of isopropanol / water mixed buffer (volume ratio 95:5, pH adjusted to 5.5), and sonicate for 28min; add 1.5g of medical-grade polyethylene glycol silane, stir and react in a 40℃ constant temperature water bath for 1h, centrifuge and wash 3 times after reaction, and vacuum dry at 55℃ for 12h to obtain surface-modified mesoporous silica nanosphere powder; measure 8g of acetyltributyl citrate, and add 3.5g of silicone foam stabilizer and 0.5g of organobismuth / organozinc composite to it in sequence. The catalyst (mass ratio 1:1) and 0.1g of pure dimethyl silicone oil (extremely low viscosity 100cSt) were mixed evenly and then all the surface-modified mesoporous silica nanospheres prepared above were added. The mixture was dispersed for 15 minutes at a speed of 2500r / min using a high-shear disperser to obtain a breathable modified slurry. The slurry was then added to the above water-absorbing modified prepolymer which was kept at a constant temperature of 45℃. The stirring speed was adjusted to 450r / min, and the reaction was continued at a constant temperature for 1.5h. After the reaction was completed, the system temperature was kept at a constant temperature of 45℃ to obtain a double-modified polyurethane mother liquor.
[0035] Step 4: Measure 160g of the double-modified polyurethane mother liquor maintained at 45℃ and place it in a foaming cup. Add 6g of absolutely dry medical-grade SAP (particle size distribution 150-300μm) and stir at 500r / min for 15s to suspend it uniformly. In another container, prepare the aqueous phase component by mixing 1.5g of deionized water, 1.5g of chain extender 1,4-butanediol, and 0.1g of trace amine catalyst evenly and maintaining it at room temperature. Quickly inject this aqueous phase component into the foaming cup. In the mother liquor of suspended SAP, the foaming machine is immediately turned on and subjected to high-speed, high-force shearing and stirring at a speed of 1800 r / min, with the stirring time precisely controlled to 8 seconds. Then, the mixed slurry is quickly poured into an aviation aluminum mold preheated to 65°C and sprayed with Teflon release agent. It is first initially cured at 65°C for 1.2 hours, and then heated to 75°C for constant temperature curing for 2.5 hours. After curing, the mold is removed, and the foam is placed in an empty drying oven at 60°C for 5 hours to obtain medical water-absorbing and breathable polyurethane foam material.
[0036] Example 4 A method for preparing a medical absorbent and breathable polyurethane foam material includes the following steps: Step 1: Weigh 80g of medical-grade polyethylene glycol (molecular weight approximately 2000), 12g of medical-grade EO-terminated polypropylene glycol (molecular weight approximately 2000), and 15g of side-chain hydrophilic diol (Ymer N120) and place them in a vacuum drying oven. Dehydrate under vacuum at 105℃ for 2.5h. After dehydration, cool to 45℃ and transfer to a three-necked flask. Accurately add 80g of medical-grade HDI trimer and dropwise add 0.15g of medical-grade organic bismuth catalyst. Purge with high-purity nitrogen for continuous protection. Adjust the mechanical stirring speed to 350r / min. First, raise the temperature to 65℃ and react at a constant temperature for 1.5h. Then, raise the temperature to 85℃ and continue reacting at a constant temperature for 3h. After the reaction is complete, cool to 60℃ for later use to obtain the basic prepolymer.
[0037] Step 2: Weigh 2.5g of nano-hydroxyapatite and add it to 50mL of ethanol / water mixture (volume ratio 95:5, pH adjusted to 4.5 with glacial acetic acid). Disperse the mixture ultrasonically at 350W for 35min. Then add 1.5g of medical-grade polyethylene glycol silane. Place the system in a 60℃ water bath and stir for 2h. After the reaction, centrifuge the product three times and wash it with anhydrous ethanol. Dry the product in an 80℃ vacuum drying oven for 12h to obtain surface-modified nano-hydroxyapatite powder. Measure 12g of vacuum-dehydrated acetylated tributyl citrate and keep it at 60℃. Add all the modified nano-hydroxyapatite dry powder prepared above and disperse it at a high speed of 2500r / min for 15min using a high-shear disperser to obtain a precursor slurry. Add all of the precursor slurry to the above-mentioned basic prepolymer, which is kept at 60℃. Adjust the stirring speed to 550r / min and stir the reaction at a constant temperature for 3h. After the reaction is completed, cool it down to 45℃ for later use to obtain the water-absorbing modified prepolymer.
[0038] Step 3: Weigh 3.5g of pure mesoporous silica nanospheres and add them to 50mL of isopropanol / water mixed buffer (volume ratio 95:5, pH adjusted to 5.5), and sonicate for 28min; add 2.0g of medical-grade polyethylene glycol silane, stir and react in a 40℃ constant temperature water bath for 1h, centrifuge and wash 3 times after reaction, and vacuum dry at 55℃ for 12h to obtain surface-modified mesoporous silica nanosphere powder; measure 8g of acetyltributyl citrate, and add 3.5g of silicone foam stabilizer and 0.5g of organobismuth / organozinc composite to it in sequence. The catalyst (mass ratio 1:1) and 0.1g of pure dimethyl silicone oil (extremely low viscosity 100cSt) were mixed evenly and then all the surface-modified mesoporous silica nanospheres prepared above were added. The mixture was dispersed for 15 minutes at a speed of 2500r / min using a high-shear disperser to obtain a breathable modified slurry. The slurry was then added to the above water-absorbing modified prepolymer which was kept at a constant temperature of 45℃. The stirring speed was adjusted to 450r / min, and the reaction was continued at a constant temperature for 1.5h. After the reaction was completed, the system temperature was kept at a constant temperature of 45℃ to obtain a double-modified polyurethane mother liquor.
[0039] Step 4: Measure 160g of the double-modified polyurethane mother liquor maintained at 45℃ and place it in a foaming cup. Add 8.0g of absolutely dry medical-grade SAP (particle size distribution 150-300μm) and stir at 500r / min for 15s to suspend it uniformly. In another container, prepare the aqueous phase component by mixing 1.5g of deionized water, 1.5g of chain extender 1,4-butanediol, and 0.1g of trace amine catalyst evenly and maintaining it at room temperature. Quickly inject this aqueous phase component into the foaming cup. The mother liquor of SAP was immediately started and foaming machine was turned on to perform high-speed and strong shearing and stirring at a speed of 1800 r / min, with the stirring time precisely controlled to 8 seconds. Then, the mixed slurry was quickly poured into an aviation aluminum mold that was preheated to 65°C and sprayed with Teflon release agent. It was first initially cured at 65°C for 1.2 hours, and then heated to 75°C for constant temperature curing for 2.5 hours. After curing, the mold was demolded and the foam was placed in an empty drying oven at 60°C for 5 hours to obtain medical water-absorbing and breathable polyurethane foam material.
[0040] Example 5 A method for preparing a medical absorbent and breathable polyurethane foam material includes the following steps: Step 1: Weigh 80g of medical-grade polyethylene glycol (molecular weight approximately 2000), 8g of medical-grade EO-terminated polypropylene glycol (molecular weight approximately 2000), and 10g of side-chain hydrophilic diol (Ymer N120) and place them in a vacuum drying oven. Dehydrate under vacuum at 105℃ for 2.5h. After dehydration, cool to 45℃ and transfer to a three-necked flask. Accurately add 70g of medical-grade HDI trimer and dropwise add 0.15g of medical-grade organic bismuth catalyst. Purge with high-purity nitrogen for continuous protection. Adjust the mechanical stirring speed to 350r / min, first raise the temperature to 65℃ and react at a constant temperature for 1.5h, then raise the temperature to 85℃ and continue reacting at a constant temperature for 3h. After the reaction is completed, cool to 60℃ for later use to obtain the basic prepolymer.
[0041] Step 2: Weigh 2.5g of nano-hydroxyapatite and add it to 50mL of ethanol / water mixture (volume ratio 95:5, pH adjusted to 4.5 with glacial acetic acid). Disperse the mixture ultrasonically at 350W for 35min. Then add 1.0g of medical-grade polyethylene glycol silane. Place the system in a 60℃ water bath and stir for 2h. After the reaction, centrifuge the product three times and wash it with anhydrous ethanol. Dry the product in an 80℃ vacuum drying oven for 12h to obtain surface-modified nano-hydroxyapatite powder. Measure 8g of vacuum-dehydrated acetylated tributyl citrate and keep it at 60℃. Add all the modified nano-hydroxyapatite dry powder prepared above and disperse it at a high speed of 2500r / min for 15min using a high-shear disperser to obtain a precursor slurry. Add all of the precursor slurry to the above-mentioned basic prepolymer, which is kept at 60℃. Adjust the stirring speed to 550r / min and stir the reaction at a constant temperature for 3h. After the reaction is completed, cool it down to 45℃ for later use to obtain the water-absorbing modified prepolymer.
[0042] Step 3: Weigh 3.5g of pure mesoporous silica nanospheres and add them to 50mL of isopropanol / water mixed buffer (volume ratio 95:5, pH adjusted to 5.5), and sonicate for 28min; add 1.0g of medical-grade polyethylene glycol silane, stir and react in a 40℃ constant temperature water bath for 1h, centrifuge and wash 3 times after reaction, and vacuum dry at 55℃ for 12h to obtain surface-modified mesoporous silica nanosphere powder; measure 8g of acetyltributyl citrate, and add 3.5g of silicone foam stabilizer and 0.5g of organobismuth / organozinc composite to it in sequence. The catalyst (mass ratio 1:1) and 0.1g of pure dimethyl silicone oil (extremely low viscosity 100cSt) were mixed evenly and then all the surface-modified mesoporous silica nanospheres prepared above were added. The mixture was dispersed for 15 minutes at a speed of 2500r / min using a high-shear disperser to obtain a breathable modified slurry. The slurry was then added to the above water-absorbing modified prepolymer which was kept at a constant temperature of 45℃. The stirring speed was adjusted to 450r / min, and the reaction was continued at a constant temperature for 1.5h. After the reaction was completed, the system temperature was kept at a constant temperature of 45℃ to obtain a double-modified polyurethane mother liquor.
[0043] Step 4: Measure 160g of the double-modified polyurethane mother liquor maintained at 45℃ and place it in a foaming cup. Add 4.0g of absolutely dry medical-grade SAP (particle size distribution 150-300μm) and stir at 500r / min for 15s to suspend it uniformly. In another container, prepare the aqueous phase component by mixing 1.5g of deionized water, 1.5g of chain extender 1,4-butanediol, and 0.1g of trace amine catalyst evenly and maintaining it at room temperature. Quickly inject this aqueous phase component into the foaming cup. The mother liquor of SAP was immediately started and foaming machine was turned on to perform high-speed and strong shearing and stirring at a speed of 1800 r / min, with the stirring time precisely controlled to 8 seconds. Then, the mixed slurry was quickly poured into an aviation aluminum mold that was preheated to 65°C and sprayed with Teflon release agent. It was first initially cured at 65°C for 1.2 hours, and then heated to 75°C for constant temperature curing for 2.5 hours. After curing, the mold was demolded and the foam was placed in an empty drying oven at 60°C for 5 hours to obtain medical water-absorbing and breathable polyurethane foam material.
[0044] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that step 2 is omitted, and the water-absorbing modified prepolymer in step 3 is replaced with the unmodified basic prepolymer obtained in step 1.
[0045] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that step 3 is omitted, and the double-modified polyurethane mother liquor in step 4 is replaced with the water-absorbing modified prepolymer obtained in step 2.
[0046] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that medical-grade EO-terminated polypropylene glycol is not added in step 1, and pure dimethyl silicone oil is not added in step 3.
[0047] Performance testing: 1. Free Absorption Rate Test: The test was conducted according to YY / T 0471.1-2004 "Test Methods for Contact Wound Dressings - Part 1: Liquid Absorption". The foam material to be tested was cut into 50mm × 50mm square samples, with three parallel samples prepared for each group. The initial mass m0 of each sample was weighed. The sample was completely immersed in simulated wound exudate (0.9% sodium chloride saline) at 37℃, ensuring no curling or folding. After free immersion for 30 minutes, the sample was held vertically by one corner with tweezers for 30 seconds. Once no more liquid dripped, the mass m1 after absorption was quickly weighed. The absorption rate (g / g) was calculated using the formula: Absorption Rate (g / g) = (m1 - m0) / m0. The arithmetic mean of the three parallel samples was taken as the final result. The test results are shown in Table 1.
[0048] 2. The test was conducted according to Appendix A of YY / T 0471.1-2004. The foam material to be tested was cut into 100mm × 100mm square samples, with three samples prepared in parallel for each group. These samples were placed horizontally on a flat glass table. Using a pipette, 1 mL of 0.9% sodium chloride physiological saline at 37℃ was vertically added to the center of the sample from a height of 10mm above the sample surface. A stopwatch was started simultaneously, and the timing was stopped when the droplet was completely absorbed by the sample and no reflective liquid film remained on the surface. The absorption time was recorded. Each group of samples was tested three times, and the arithmetic mean of all test results was taken as the final absorption rate, expressed in seconds. The test results are shown in Table 1.
[0049] 3. Water vapor transmission rate test: The water vapor transmission rate was tested using the permeation cup method according to YY / T 0471.2-2004 "Test Methods for Contact Wound Dressings Part 2: Water Vapor Transmission Rate of Breathable Membrane Dressings". The test environment was a temperature of (38±1)℃ and a relative humidity of (20±2)%. Three circular samples with a diameter of 74mm were prepared for each group of foam material to be tested. 20mL of distilled water was added to the permeation cup, and the sample was evenly placed over the cup opening and sealed to prevent leakage. The initial total mass M0 of the permeation cup was weighed. After placing the permeation cup horizontally in the test environment for 24 hours, the total mass M1 was weighed again. The water vapor transmission rate was calculated using the formula: Water vapor transmission rate (g / (m...)) = ... 2 •24h))=(M1-M0) / (S×t)×10 6 Calculate, where S is the effective moisture permeability area of the sample (m²). 2 ), where t is the test time (h), and the arithmetic mean of three parallel samples is taken as the final result. The test results are shown in Table 1.
[0050] 4. Cell connectivity test: A fully automated true density analyzer was used, employing the gas displacement specific gravity bottle method. The foam sample to be tested was taken, and first the apparent total volume Vtotal of the sample was measured. Then, the closed-cell volume Vclosed of the sample was measured. The formula was: Cell connectivity (%) = (Vtotal / Vclosed). 总 -V 闭 ) / V 总 The result was calculated as ×100%; each group of samples was tested in parallel three times, and the arithmetic mean was taken as the final result to characterize the permeability of the foam channels. The test results are shown in Table 1.
[0051] 5. Tensile Strength Test: The test was conducted according to GB / T 6344-2008 "Determination of Tensile Strength and Elongation at Break of Flexible Foam Polymer Materials". The foam material to be tested was cut into standard dumbbell-shaped specimens with a gauge length of 25 mm and a total specimen length of 115 mm. Five specimens were prepared in parallel for each group. A universal electronic tensile testing machine was used to test at a constant tensile rate of 500 mm / min. The maximum tensile force F at specimen breakage was recorded. The tensile strength (MPa) was calculated according to the formula F / (b×d) (where b is the width of the gauge length and d is the specimen thickness). The arithmetic mean of the five parallel specimens was taken as the final result. The test results are shown in Table 1.
[0052] 6. The biocompatibility of the material was evaluated according to GB / T16886.4-2003 "Biological Evaluation of Medical Devices Part 4: Selection of Blood Interaction Tests". Fresh rabbit blood was diluted with physiological saline to prepare a 2% red blood cell suspension. 5g of the foam sample to be tested was placed in 10mL of physiological saline and incubated at 37℃ for 30min. Then, 0.2mL of the red blood cell suspension was added, and incubation continued for 2h. Simultaneously, a physiological saline negative control group and a distilled water positive control group were set up, with 3 samples in each group. After incubation, the sample was centrifuged at 3000r / min for 5min, and the absorbance of the supernatant was measured at 545nm. The hemolysis rate (%) was calculated using the formula: Hemolysis rate (%) = (Sample absorbance - Negative control absorbance) / (Positive control absorbance - Negative control absorbance) × 100%. A hemolysis rate ≤ 5% was considered to meet the biocompatibility requirements for medical materials. The test results are shown in Table 1.
[0053] Table 1: Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a medical-grade absorbent and breathable polyurethane foam material, characterized in that, Includes the following steps: (1) After dehydrating polyethylene glycol, EO-terminated polypropylene glycol and side-chain hydrophilic diol, it is reacted with HDI trimer and organic bismuth catalyst to obtain the basic prepolymer; (2) After the nano-hydroxyapatite is modified with polyethylene glycol silane, it is mixed and dispersed with acetyl tributyl citrate, and then added to the basic prepolymer to react and obtain a water-absorbing modified prepolymer. (3) After the mesoporous silica nanospheres are modified with polyethylene glycol silane, they are mixed and dispersed with acetyl tributyl citrate, silicone foam stabilizer, organobismuth / organozinc composite catalyst and dimethyl silicone oil, and then added to the water-absorbing modified prepolymer to react and obtain the double-modified polyurethane mother liquor. (4) Mix the double-modified polyurethane mother liquor with medical grade SAP, then add an aqueous phase consisting of water, 1,4-butanediol and amine catalyst, stir at high speed and inject into a mold, and after curing and drying, obtain medical water-absorbing and breathable polyurethane foam material.
2. The method for preparing a medical absorbent and breathable polyurethane foam material according to claim 1, characterized in that, In step (1), the mass ratio of polyethylene glycol, EO-terminated polypropylene glycol, and side-chain hydrophilic diol is 8:(0.8-1.2):(1.0-1.5).
3. The method for preparing a medical absorbent and breathable polyurethane foam material according to claim 1, characterized in that, In step (1), the mass ratio of polyethylene glycol to HDI trimer is 8:(7-8).
4. The method for preparing a medical absorbent and breathable polyurethane foam material according to claim 1, characterized in that, In step (2), the mass ratio of nano-hydroxyapatite to polyethylene glycol silane is 2.5:(1.0~1.5).
5. The method for preparing a medical absorbent and breathable polyurethane foam material according to claim 1, characterized in that, In step (2), the mass ratio of nano-hydroxyapatite to acetylated tributyl citrate is 2.5:(8-12).
6. The method for preparing a medical absorbent and breathable polyurethane foam material according to claim 1, characterized in that, In step (3), the mass ratio of mesoporous silica nanospheres to polyethylene glycol silane is 3.5:(1-2).
7. The method for preparing a medical absorbent and breathable polyurethane foam material according to claim 1, characterized in that, In step (4), the mass ratio of the double-modified polyurethane mother liquor to the medical-grade SAP is 160:(4-8).
8. A medical-grade absorbent and breathable polyurethane foam material, characterized in that, It is prepared by the method described in any one of claims 1 to 7.