A water permeable, air impermeable oxygen delivery tubing and method of manufacture

Abstract

This invention relates to the field of medical materials technology, specifically to a water-permeable but air-impermeable oxygen delivery tubing and its preparation method. The oxygen delivery tubing has a double-layer structure, with the inner layer being a water-permeable but air-impermeable polyester film and the outer layer being a spiral-supported tube wall. The oxygen delivery tubing of this invention is composed of an inner layer of water-permeable but air-impermeable polyester film and an outer layer of spiral-supported tube wall. The inner polyester film possesses the characteristic of unidirectional permeability of liquid water molecules and isolation and blocking of gas molecules, achieving a water-permeable and gas-blocking effect. The outer tube wall has a continuous spiral integral molding structure, relying on spiral ribs to form a three-dimensional support skeleton, which can maintain the overall diameter and shape of the tube, resist bending and collapse, and improve the structural strength and flexibility of the tube, ensuring unobstructed oxygen delivery.

Description

Technical Field

[0001] This invention relates to the field of medical materials technology, specifically to a water-permeable but air-impermeable oxygen delivery pipe and its preparation method. Background Technology

[0002] Breathing tubing is mainly used to connect ventilators, anesthesia machines and the patient's airway. It can accurately deliver the prepared medical mixed gas into the patient's body, promptly expel the carbon dioxide waste gas exhaled by the body, and maintain normal ventilation circulation. In real life, there are significant differences in the amount of water vapor produced during respiration among people with different constitutions. Those with a constitution that is prone to heat, or those with yin deficiency and excessive fire, have more body fluids that evaporate vigorously, resulting in warmer breath and higher water vapor content in their exhaled air. Conversely, those with a constitution that is prone to cold, or those with insufficient yang energy, have weaker water vapor metabolism, resulting in colder breath and less water evaporation from their body surface and respiratory tract, leading to a relatively lower amount of exhaled water vapor. Furthermore, people with phlegm-dampness constitution have excessive dampness in their bodies, resulting in thicker and larger amounts of exhaled water vapor. People with qi deficiency and weakness breathe shallowly and slowly, with a slower gas exchange rate, resulting in a lower total amount of exhaled water vapor. At the same time, their lifestyle and metabolic rate further widen the gap in water vapor expulsion among people with different constitutions. Therefore, existing respiratory tubing materials, when used for patients with high exhaled air water content, are limited by their permeability and cannot completely remove the condensate, leading to the problem of condensate backflowing into the patient's respiratory tract.

[0003] For example, Chinese patent CN115558283B discloses a water-permeable but air-impermeable plastic raw material for breathing tubing and its preparation method. The raw materials include: 20-40 parts of dicarboxylic acid, 25-35 parts of 1,4-butanediol, 32-52 parts of polyether polyol, 0.1-1 parts of antibacterial agent, 0.01-0.3 parts of catalyst, 0.01-1 parts of end-capping agent, 0.1-0.5 parts of antioxidant, and 0.01-0.3 parts of reducing agent. This allows the provided product to meet the requirements for breathing tubing compliance while ensuring the safety of the product. Under the premise of the required temperature and humidity, the condensate can be allowed to pass through, ensuring that there is no water accumulation in the breathing tube, eliminating the risk of choking on the patient, reducing the workload of nursing staff, and effectively preventing the growth of Pseudomonas aeruginosa, Staphylococcus aureus, and mold, thus eliminating potential infection risks. However, although the plastic material has a certain degree of water permeability, when the amount of condensate produced by the patient's breathing is large, it cannot be discharged quickly and is prone to condensation accumulation in the breathing tube. This not only makes it easy for condensate to flow back into the patient's airway, but also makes it easy for bacteria to grow, causing safety hazards. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of this invention is to provide a water-permeable but air-impermeable oxygen transport pipe and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A water-permeable but air-permeable oxygen transport pipe is provided. The oxygen transport pipe has a double-layer structure, with the inner layer being a water-permeable but air-permeable polyester film and the outer layer being a spiral-supported pipe wall. The water-permeable but air-permeable polyester film is prepared by adding an antibacterial agent solution to a polyurethane solution to obtain an antibacterial polyurethane solution. Then, a composite nanofiber membrane is stacked by a layer-by-layer rotational misalignment method. The antibacterial polyurethane solution is uniformly impregnated into the gaps between the multi-layer stacked composite nanofiber membranes using a micro-coating method, and then cured at low temperature. The spiral support tube wall is made of medical-grade thermoplastic polyurethane material.

[0006] As a further preferred embodiment of the present invention, the water-permeable but air-impermeable polyester film is prepared by the following method: 1) Add polyurethane particles to a solvent and stir slowly at 60-65℃ until completely dissolved to obtain a polyurethane solution. Then add medical quaternary ammonium antibacterial agent to the solvent and stir thoroughly at room temperature to obtain an antibacterial agent stock solution. Then slowly add the antibacterial agent stock solution to the polyurethane solution and stir slowly to obtain an antibacterial polyurethane solution. 2) Select 3-5 composite nanofiber membranes and stack them in a staggered, rotating manner, with the angle between adjacent layers of fiber membranes offset by 30°-60°. Then, gently press them to make the fiber membranes stack tightly. Next, use a micro-coating method to uniformly impregnate the antibacterial polyurethane solution into the gaps between the multilayer stacked fiber membranes. Strictly control the impregnation amount, only filling the interlayer and inter-fiber gaps without blocking the pores of the hollow fibers. Place the impregnated membrane in a low-temperature, slow-curing environment of 40-50℃ for 25-35 minutes, and allow it to cool naturally before demolding to obtain a water-permeable but air-permeable polyester film.

[0007] Furthermore, the polyurethane particles are made of polyether-type thermoplastic polyurethane elastomer, with soft segments accounting for 50-80% and hard segments accounting for 20-50%. The solvent is obtained by mixing anhydrous ethanol and deionized water in a volume ratio of (7-8):(2-3); The polyurethane solution has a concentration of 5-8 wt%. The concentration of the antibacterial agent stock solution is 3-5 wt%. The antibacterial polyurethane solution contains an antibacterial agent at a concentration of 0.5-1.0 wt% of the polyurethane solid content.

[0008] As a further preferred embodiment of the present invention, the composite nanofiber membrane is prepared by the following method: 1) After purging the hollow porous nanofiber membrane with anhydrous ethanol, let it stand at room temperature for 10-20 min to obtain a pretreated fiber membrane. Then, after stirring and mixing deionized water and anhydrous ethanol, add glacial acetic acid, stir thoroughly, and slowly add tetrabutyl titanate dropwise. After the dropwise addition is complete, stir thoroughly to obtain the precursor reaction solution. 2) Place the pretreated fiber membrane flat and suspended in the middle of the lining of the hydrothermal reactor. You can use the PTFE fine support suspension method or the PTFE hollow mesh suspension method. Then slowly pour the precursor reaction solution into the lining to completely immerse the pretreated fiber membrane. Let it stand for 10-20 minutes to soak. Seal the hydrothermal reactor and react at a constant temperature for 2-3 hours. After the reaction is completed, let it cool naturally to room temperature. Slowly remove the fiber membrane, rinse it repeatedly with anhydrous ethanol and deionized water, and then dry it in an oven for 60-100 minutes.

[0009] Furthermore, in the precursor reaction solution, the volume ratio of deionized water, anhydrous ethanol, glacial acetic acid, and tetrabutyl titanate is (5-10):(35-70):(2-4):(1.2-2.4). The isothermal reaction is carried out at a temperature of 90-95℃. The drying process takes place at a temperature of 40-45℃.

[0010] As a further preferred embodiment of the present invention, the hollow porous nanofiber membrane is prepared by the following method: 1) Add polyurethane particles to a mixed solvent consisting of N,N-dimethylformamide and tetrahydrofuran, place it in a constant temperature water bath at 50-55℃ and stir magnetically for 4-6 hours, then add polyethylene glycol (PEG2000), continue stirring for 2-3 hours, and let it stand at room temperature to degas for 1-3 hours to obtain the shell spinning solution. 2) Mix Tween 80 evenly into mineral oil and stir magnetically for 30-50 minutes at room temperature to obtain core spinning solution. Then, at room temperature and relative humidity of 40-50%, perform coaxial electrospinning using a dual-channel coaxial needle (inner needle 0.2mm, outer needle 0.8mm). Add micro-nozzles symmetrically on both sides of the coaxial nozzle and introduce dry low-pressure nitrogen gas of 0.08-0.15MPa, sweeping it laterally across the spinning jet. After spinning is completed, obtain nanofiber membrane. 3) Immerse the nanofiber membrane obtained by spinning completely in n-hexane solution and extract in a sealed container at room temperature for 36-40 hours. After extraction, remove the nanofiber membrane, air dry it at room temperature, place it in a drying oven, anneal it at a constant temperature for 1-2 hours, and then cool it naturally to room temperature.

[0011] Furthermore, in step 1), the polyurethane particles are selected from polyether-type thermoplastic polyurethane elastomers, with soft segments accounting for 50-80% and hard segments accounting for 20-50%. In the shell spinning solution, the mass ratio of polyurethane particles, polyethylene glycol, and mixed solvent is (12-15):(4-7):(80-85). The mixed solvent is composed of N,N-dimethylformamide and tetrahydrofuran in a volume ratio of (6-7):(3-4).

[0012] Furthermore, in step 2), the mass ratio of Tween 80 to mineral oil in the core spinning solution is (0.5-0.8):(99.2-99.5). The electrospinning process has the following specific parameters: spinning voltage 14-18kV, receiving distance 15-20cm, shell liquid flow rate 1.0-1.3mL / h, and core liquid flow rate 0.2-0.4mL / h.

[0013] Furthermore, in step 3), during the extraction, the n-hexane is replaced every 8-10 hours; The isothermal annealing is performed at a temperature of 70-75℃.

[0014] A method for preparing a water-permeable but air-impermeable oxygen transport pipe, the specific preparation method is as follows: First, a water-permeable but air-permeable polyester film is rolled into a cylindrical inner layer film. Then, polyurethane particles are fed into a screw extruder to obtain a spiral tubular structure, which is then wrapped and adhered to the outer surface of the cylindrical inner layer film. After shaping and cutting, an oxygen transmission pipe can be obtained. Specifically, a water-permeable but air-permeable polyester film is rolled into a cylindrical inner layer film. The raw material polyurethane particles are fed into a screw extruder and extruded from the screw forming die to form a spiral tubular structure, which provides support. The outer spiral support pipe wall is then wrapped and attached to the outer surface of the cylindrical inner layer film. After cooling, shaping, traction, and cutting, a water-permeable but air-permeable oxygen transport pipe can be obtained.

[0015] Compared with the prior art, the beneficial effects of the present invention are: In this invention, a thermosensitive soft-segment polymer polyurethane is selected as the shell material, polyethylene glycol as the pore-forming agent, and Tween 80 and food-grade mineral oil as the core material. A nanofiber membrane is obtained by coaxial electrospinning. Due to the large difference in solubility between the core material and the shell spinning solution, the two phases are completely immiscible. During spinning, the two phases maintain a core-shell layered structure. In the subsequent soaking and extraction, the mineral oil in the core spinning solution is completely dissolved, while the outer polyurethane shell has solidified and set, thus forming an axially interconnected, regular, and stable hollow cavity structure. Furthermore, during the drying process, the polyethylene glycol in the shell undergoes micro-migration and thermal decomposition at high temperature, forming uniformly interconnected nanopores in the polyurethane shell, creating a porous structure, thereby obtaining a hollow porous nanofiber membrane. This hollow porous nanofiber membrane is hollow internally, with the tube walls filled with nanoscale interconnected pores, and gaps exist between individual fibers. After being embedded in the polyurethane matrix, the membrane interior forms a combination of inter-fiber accumulation pores + tube wall through-pores + The "three-dimensional interconnected, gradient pore size" network of the internal channels allows water vapor to pass through the internal cavity, the nanopores in the tube wall, and the pores between the fibers simultaneously. This multi-level parallel channel structure provides excellent water permeability. Although air molecules are small, air flows as a whole. The multi-level channel structure results in extremely high air convection resistance, which strongly inhibits air convection and prevents it from passing through the fiber membrane. This gives the hollow porous nanofiber membrane excellent water permeability but no air permeability. Moreover, when the polyurethane in the shell material is heated, the thermal motion of its soft segment molecules intensifies, the chain segments stretch, the free volume increases, and the fiber as a whole expands slightly. At the same time, the small amount of air sealed in the internal hollow cavity is heated and pressurized, which helps to expand the shell structure. This causes the hollow channel pore size of the fiber membrane to expand slightly. Driven by the temperature and pressure difference between the inside and outside, water vapor can quickly penetrate the micropore channels, increasing the water permeability rate. However, the air molecules are relatively large, and even after the pores are expanded, they still cannot form an effective airflow to penetrate, maintaining the air barrier properties. Meanwhile, to further enhance the water permeability and air impermeability of the hollow porous nanofiber membrane, this invention symmetrically adds micro-nozzles on both sides of the coaxial nozzle during the electrospinning process, introducing dry, low-pressure nitrogen gas, which sweeps laterally across the spinning jet. Utilizing the combined effects of electric field tension and lateral airflow shear force, the spinning jet solidifies to form single spiral, wavy, coiled nanofibers. Each fiber possesses its own micro-curved water vapor channels, lacking a straight fiber structure. Embedded within the polyurethane matrix, the entire interior of the membrane consists of highly tortuous, meandering channels, significantly improving gas permeability. The resistance completely blocks air convection and permeation, while water vapor molecules can diffuse and penetrate efficiently, thus achieving better water permeability and air impermeability. Furthermore, in the subsequent film preparation, the fiber membrane is stacked in a layer-by-layer rotational staggered manner. By gently pressing, the interlayer fibers are tightly interlocked and the nodes are embedded to form a three-dimensional interlocking network. The structure is mechanically self-locking, making it difficult for the bent nanofibers to return to straightness. This results in the formation of structurally stable, highly tortuous, meandering channels in the film, which promotes the improvement of the film's water permeability and air impermeability. Furthermore, to further improve the structural stability of the tortuous channels within the film, this invention employs a low-temperature hydrothermal method, using tetrabutyl titanate as the titanium source. Titanium dioxide nanowires are grown on the surface of a hollow porous nanofiber membrane via a hydrothermal reaction. Since the nanowires grow on the surface of the fiber membrane, they do not clog the hollow structure of the fibers. Through the intertwining and connection between the nanowires, the individual fibers in the fiber membrane are linked together, providing a rigid locking effect and inhibiting the return of individual fibers to straightness, allowing them to achieve permanent plastic bending, thereby enhancing the structural stability of the tortuous channels within the film. Moreover, the cross-linked network structure formed by the intertwined nanowires can also limit the expansion of the fiber membrane, effectively inhibiting excessive expansion of the hollow channels inside the fibers due to heat, reducing the squeezing effect of the fibers on the surrounding polyurethane matrix, stabilizing the overall dense structure of the polyurethane film, and preventing air permeability. Simultaneously, the nanowire network precisely controls the permeability size of the channels, enhancing the air barrier effect at room temperature and ensuring efficient water vapor permeability at high temperatures, maintaining the film's excellent water-permeable but air-impermeable properties throughout, significantly improving the stability and practicality of the material for recycling.

[0016] In this invention, composite nanofiber membranes are stacked in a layer-by-layer rotating and staggered manner, causing the fiber channels of the upper and lower layers to intersect, block, and shift, forming a regular, meandering water vapor transport path between layers. This completely eliminates vertical through-holes and hidden pores, allowing water vapor to diffuse and penetrate layer by layer along the tortuous channels between layers. Air, due to the multi-layer cross-blocking, cannot form convection permeation. Combined with the liquid water barrier capability of the antibacterial polyurethane dense matrix, a stable water-permeable but air-permeable function is achieved. This gives the water-permeable but air-permeable polyester film excellent water permeability and air permeability, and it can effectively inhibit the growth of bacteria and mold, making it suitable for medical oxygen delivery scenarios.

[0017] The oxygen delivery pipe of this invention is composed of an inner layer of water-permeable but air-impermeable polyester film and an outer layer of spiral support pipe wall. The inner polyester film has the characteristics of unidirectional permeability of liquid water molecules and isolation and blocking of gas molecules, which can achieve the effect of water permeability and gas blocking. The outer pipe wall has a continuous spiral integral molding structure, which relies on the spiral ribs to form a three-dimensional support skeleton, which can not only maintain the overall diameter shape of the pipe and resist bending and collapse, but also improve the structural strength and flexibility of the pipe, ensuring the smooth flow of oxygen delivery channel. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In this embodiment of the invention, the polyurethane particles selected are Sichuan Youborui UBR Ultra-Soft 60A, with a polyether soft segment mass ratio of 70-75% and a hard segment mass ratio of 25-30%. The polyethylene glycol is PEG2000; Dual-channel coaxial needle, inner needle 0.2mm, outer needle 0.8mm; For medical use, dodecyl dimethyl benzyl ammonium chloride is selected as the quaternary ammonium antibacterial agent. The pretreated fiber membrane was laid flat and suspended in the middle of the lining of the hydrothermal reactor using a PTFE fine support suspension method.

[0020] Example 1 A water-permeable but air-permeable oxygen delivery pipe, which has a double-layer structure, with the inner layer being a water-permeable but air-permeable polyester film and the outer layer being a spiral-supported pipe wall. The outer spiral support tube wall is made of medical-grade thermoplastic polyurethane material; The inner layer of water-permeable but air-permeable polyester film is prepared as follows: 1) Anhydrous ethanol and deionized water were mixed at a volume ratio of 7:3 to obtain a solvent. Polyurethane particles were added to the solvent and stirred slowly at 60°C until completely dissolved to obtain a 5wt% polyurethane solution. Medical quaternary ammonium antibacterial agent was then added to the solvent and stirred thoroughly at room temperature to obtain a 3wt% antibacterial agent stock solution. The antibacterial agent stock solution was then slowly added to the polyurethane solution, controlling the antibacterial agent content to be 0.5wt% of the polyurethane solid content. After slow stirring, an antibacterial polyurethane solution was obtained. 2) Select 3 composite nanofiber membranes and stack them in a staggered, rotating manner, with the angle between adjacent layers of fiber membranes staggered by 30° and gently pressed to make the fiber membranes stacked tightly. Then, use a micro-coating method to uniformly impregnate the gaps between the multilayer stacked fiber membranes with antibacterial polyurethane solution. Place the impregnated membrane in a 40°C environment for low-temperature slow curing for 25 minutes, and allow it to cool and demold naturally to obtain a water-permeable but air-permeable polyester film. The specific steps for preparing this oxygen delivery pipe are as follows: First, a water-permeable but air-permeable polyester film is rolled into a cylindrical inner film. Then, polyurethane granules are fed into a screw extruder to obtain a spiral tubular structure, which is then wrapped and adhered to the outer surface of the cylindrical inner film. After shaping and cutting, an oxygen transmission pipe can be obtained.

[0021] The specific preparation method of the composite nanofiber membrane is as follows: 1) Weigh polyurethane particles, polyethylene glycol, and a mixed solvent consisting of N,N-dimethylformamide and tetrahydrofuran in a volume ratio of 6:4 according to a mass ratio of 12:4:84. Then add the polyurethane particles to the mixed solvent and place it in a 50°C constant temperature water bath and stir magnetically for 4 hours. Then add polyethylene glycol and continue stirring for 2 hours. Let it stand at room temperature for 1 hour to remove bubbles and obtain the shell spinning solution. 2) Weigh Tween 80 and mineral oil according to a mass ratio of 0.5:99.5. Then, mix Tween 80 evenly into the mineral oil and stir magnetically for 30 minutes at room temperature to obtain the core spinning solution. Then, at room temperature and 40% relative humidity, perform coaxial electrospinning using a dual-channel coaxial needle. Add micro nozzles symmetrically on both sides of the coaxial nozzle and introduce dry low-pressure nitrogen gas at 0.08 MPa. Sweep the spinning jet laterally. Control the spinning voltage at 14 kV, the receiving distance at 15 cm, the shell liquid flow rate at 1.0 mL / h, and the core liquid flow rate at 0.2 mL / h. After spinning is completed, obtain a nanofiber membrane. 3) The nanofiber membrane obtained by spinning is completely immersed in n-hexane solution and extracted in a sealed manner at room temperature for 36 hours. During this period, the n-hexane is replaced every 9 hours. After the extraction is completed, the nanofiber membrane is taken out, air-dried at room temperature, and then placed in a drying oven for constant temperature annealing at 70℃ for 1 hour. After naturally cooling to room temperature, a hollow porous nanofiber membrane can be obtained. 4) After purging the hollow porous nanofiber membrane with anhydrous ethanol, let it stand at room temperature for 10 min to obtain a pretreated fiber membrane. Then, mix 5 mL of deionized water with 35 mL of anhydrous ethanol, add 2 mL of glacial acetic acid, stir thoroughly, and slowly add 1.2 mL of tetrabutyl titanate. After the addition is complete, stir thoroughly to obtain the precursor reaction solution. 5) Place the pretreated fiber membrane flat and suspended in the middle of the lining of the hydrothermal reactor. Then slowly pour the precursor reaction solution into the lining to completely immerse the pretreated fiber membrane. Let it stand for 10 minutes to soak. Seal the hydrothermal reactor and react at 90°C for 2 hours. After the reaction is complete, let it cool naturally to room temperature. Slowly remove the fiber membrane and rinse it repeatedly with anhydrous ethanol and deionized water. Then dry it in a 40°C oven for 60 minutes to obtain the desired composite nanofiber membrane.

[0022] Example 2 A water-permeable but air-permeable oxygen delivery pipe, which has a double-layer structure, with the inner layer being a water-permeable but air-permeable polyester film and the outer layer being a spiral-supported pipe wall. The outer spiral support tube wall is made of medical-grade thermoplastic polyurethane material; The inner layer of water-permeable but air-permeable polyester film is prepared as follows: 1) Anhydrous ethanol and deionized water were mixed at a volume ratio of 8:2 to obtain a solvent. Polyurethane particles were added to the solvent and stirred slowly at 62°C until completely dissolved to obtain a 6wt% polyurethane solution. Medical quaternary ammonium antibacterial agent was then added to the solvent and stirred thoroughly at room temperature to obtain a 4wt% antibacterial agent stock solution. The antibacterial agent stock solution was then slowly added to the polyurethane solution, controlling the antibacterial agent content to be 0.8wt% of the polyurethane solid content. After slow stirring, an antibacterial polyurethane solution was obtained. 2) Select 4 composite nanofiber membranes and stack them in a staggered, rotating manner, with the angle between adjacent layers of fiber membranes staggered by 50°. Then, press them slightly to make the fiber membranes stack tightly. Then, use a micro-coating method to uniformly impregnate the gaps between the multilayer stacked fiber membranes with antibacterial polyurethane solution. Place the impregnated membrane in a 45°C environment for low-temperature slow curing for 30 minutes, and allow it to cool and demold naturally to obtain a water-permeable but air-permeable polyester film. The specific steps for preparing this oxygen delivery pipe are as follows: First, a water-permeable but air-permeable polyester film is rolled into a cylindrical inner film. Then, polyurethane granules are fed into a screw extruder to obtain a spiral tubular structure, which is then wrapped and adhered to the outer surface of the cylindrical inner film. After shaping and cutting, an oxygen transmission pipe can be obtained.

[0023] The specific preparation method of the composite nanofiber membrane is as follows: 1) Weigh out polyurethane particles, polyethylene glycol, and a mixed solvent consisting of N,N-dimethylformamide and tetrahydrofuran in a volume ratio of 7:3 according to a mass ratio of 13:5:82. Then add the polyurethane particles to the mixed solvent and place it in a constant temperature water bath at 52°C and stir magnetically for 5 hours. Then add polyethylene glycol and continue stirring for 2.5 hours. Let it stand at room temperature for 2 hours to remove bubbles and obtain the shell spinning solution. 2) Weigh Tween 80 and mineral oil according to a mass ratio of 0.7:99.3. Then, mix Tween 80 evenly into the mineral oil and stir magnetically for 40 minutes at room temperature to obtain the core spinning solution. Then, at room temperature and 45% relative humidity, perform coaxial electrospinning using a dual-channel coaxial needle. Add micro nozzles symmetrically on both sides of the coaxial nozzle and introduce 0.12MPa dry low-pressure nitrogen gas to sweep across the spinning jet laterally. Control the spinning voltage at 16kV, the receiving distance at 18cm, the shell liquid flow rate at 1.2mL / h, and the core liquid flow rate at 0.3mL / h. After spinning is completed, a nanofiber membrane is obtained. 3) The nanofiber membrane obtained by spinning is completely immersed in n-hexane solution and extracted in a sealed manner at room temperature for 38 hours. During this period, the n-hexane is replaced every 8 hours. After the extraction is completed, the nanofiber membrane is taken out, air-dried at room temperature, and then placed in a drying oven for constant temperature annealing at 72℃ for 1.5 hours. After naturally cooling to room temperature, a hollow porous nanofiber membrane can be obtained. 4) After purging the hollow porous nanofiber membrane with anhydrous ethanol, let it stand at room temperature for 15 min to obtain a pretreated fiber membrane. Then, mix 7 mL of deionized water with 55 mL of anhydrous ethanol, add 3 mL of glacial acetic acid, stir thoroughly, and slowly add 1.8 mL of tetrabutyl titanate. After the addition is complete, stir thoroughly to obtain the precursor reaction solution. 5) Place the pretreated fiber membrane flat and suspended in the middle of the lining of the hydrothermal reactor. Then slowly pour the precursor reaction solution into the lining to completely immerse the pretreated fiber membrane. Let it stand for 15 minutes to soak. Seal the hydrothermal reactor and react at a constant temperature of 92°C for 2.5 hours. After the reaction is completed, let it cool naturally to room temperature. Slowly remove the fiber membrane and rinse it repeatedly with anhydrous ethanol and deionized water. Then dry it in a 42°C oven for 80 minutes to obtain the desired composite nanofiber membrane.

[0024] Example 3 A water-permeable but air-permeable oxygen delivery pipe, which has a double-layer structure, with the inner layer being a water-permeable but air-permeable polyester film and the outer layer being a spiral-supported pipe wall. The outer spiral support tube wall is made of medical-grade thermoplastic polyurethane material; The inner layer of water-permeable but air-permeable polyester film is prepared as follows: 1) Anhydrous ethanol and deionized water were mixed at a volume ratio of 8:2 to obtain a solvent. Polyurethane particles were added to the solvent and stirred slowly at 65°C until completely dissolved to obtain a polyurethane solution with a concentration of 8wt%. Medical quaternary ammonium antibacterial agent was then added to the solvent and stirred thoroughly at room temperature to obtain an antibacterial agent stock solution with a concentration of 5wt%. The antibacterial agent stock solution was then slowly added to the polyurethane solution, controlling the antibacterial agent content to be 1.0wt% of the polyurethane solid content. After slow stirring, an antibacterial polyurethane solution was obtained. 2) Select 5 composite nanofiber membranes and stack them in a staggered, rotating manner, with the angle between adjacent layers of fiber membranes staggered by 60°. Then, press them slightly to make the fiber membranes stack tightly. Then, use a micro-coating method to uniformly impregnate the gaps between the multilayer stacked fiber membranes with antibacterial polyurethane solution. Place the impregnated membrane in a 50°C environment for low-temperature slow curing for 35 minutes, and allow it to cool and demold naturally to obtain a water-permeable but air-permeable polyester film. The specific steps for preparing this oxygen delivery pipe are as follows: First, a water-permeable but air-permeable polyester film is rolled into a cylindrical inner film. Then, polyurethane granules are fed into a screw extruder to obtain a spiral tubular structure, which is then wrapped and adhered to the outer surface of the cylindrical inner film. After shaping and cutting, an oxygen transmission pipe can be obtained.

[0025] The specific preparation method of the composite nanofiber membrane is as follows: 1) Weigh out polyurethane particles, polyethylene glycol, and a mixed solvent composed of N,N-dimethylformamide and tetrahydrofuran in a volume ratio of 7:3 according to a mass ratio of 15:7:85. Then add the polyurethane particles to the mixed solvent and place it in a 55°C constant temperature water bath and stir magnetically for 6 hours. Then add polyethylene glycol and continue stirring for 3 hours. Let it stand at room temperature for 3 hours to remove bubbles and obtain the shell spinning solution. 2) Weigh Tween 80 and mineral oil according to a mass ratio of 0.8:99.2. Then, mix Tween 80 evenly into the mineral oil and stir magnetically for 50 minutes at room temperature to obtain the core spinning solution. Then, at room temperature and 50% relative humidity, perform coaxial electrospinning using a dual-channel coaxial needle. Add micro nozzles symmetrically on both sides of the coaxial nozzle and introduce 0.15MPa dry low-pressure nitrogen gas to sweep across the spinning jet laterally. Control the spinning voltage at 18kV, the receiving distance at 20cm, the shell liquid flow rate at 1.3mL / h, and the core liquid flow rate at 0.4mL / h. After spinning is completed, a nanofiber membrane is obtained. 3) The nanofiber membrane obtained by spinning is completely immersed in n-hexane solution and extracted in a sealed manner at room temperature for 40 hours. During this period, the n-hexane is replaced every 10 hours. After the extraction is completed, the nanofiber membrane is taken out, air-dried at room temperature, and then placed in a drying oven for constant temperature annealing at 75°C for 2 hours. After naturally cooling to room temperature, a hollow porous nanofiber membrane can be obtained. 4) After purging the hollow porous nanofiber membrane with anhydrous ethanol, let it stand at room temperature for 20 min to obtain a pretreated fiber membrane. Then, mix 10 mL of deionized water with 70 mL of anhydrous ethanol, add 4 mL of glacial acetic acid, stir thoroughly, and slowly add 2.4 mL of tetrabutyl titanate. After the addition is complete, stir thoroughly to obtain the precursor reaction solution. 5) Place the pretreated fiber membrane flat and suspended in the middle of the lining of the hydrothermal reactor. Then slowly pour the precursor reaction solution into the lining to completely immerse the pretreated fiber membrane. Let it stand for 20 minutes to soak. Seal the hydrothermal reactor and react at a constant temperature of 95°C for 3 hours. After the reaction is completed, let it cool naturally to room temperature. Slowly remove the fiber membrane and rinse it repeatedly with anhydrous ethanol and deionized water. Then dry it in a 45°C oven for 100 minutes to obtain the desired composite nanofiber membrane.

[0026] Comparative Example 1: This comparative example is basically the same as Example 1, except that in the preparation process of the composite nanofiber membrane, the polyethylene glycol in the shell spinning solution in step 1) is omitted.

[0027] Comparative Example 2: This comparative example is basically the same as Example 1, except that in the preparation process of the composite nanofiber membrane, step 2) is omitted, in which micro air nozzles are symmetrically installed on both sides of the coaxial nozzle.

[0028] Comparative Example 3: This comparative example is basically the same as Example 1, except that the core spinning solution in step 2) is omitted in the preparation process of the composite nanofiber membrane.

[0029] Comparative Example 4: This comparative example is basically the same as Example 1, except that the extraction operation in the n-hexane solution in step 3) is omitted in the preparation process of the composite nanofiber membrane.

[0030] Comparative Example 5: This comparative example is basically the same as Example 1, except that steps 4)-5) are omitted in the preparation process of the composite nanofiber membrane.

[0031] Comparative Example 6: This comparative example is basically the same as Example 1, except that the composite nanofiber membranes are replaced by layer-by-layer rotating and staggered stacking in the preparation of the water-permeable but air-permeable polyester film with layer-by-layer parallel alignment stacking.

[0032] Test experiment: (1) Gas barrier performance: According to methods well known to those skilled in the art, one end of the 0.15 mm thick pipe prepared in Examples 1-3 and Comparative Examples 1-6 was connected to a gas source, and the other end was sealed with a plug. The pressure was increased to 10 kPa for testing. If the pipe did not leak, the gas barrier performance of the product was recorded as qualified; if the pipe leaked, the gas barrier performance of the product was recorded as unqualified.

[0033] (2) Water vapor transmission performance: Referring to GB / T 1037-2021 "Determination of water vapor transmission performance of plastic films and sheets - cup method"; the 30μm thick water-permeable but air-permeable polyester film samples prepared in Examples 1-3 and Comparative Examples 1-6 were cut to the appropriate size for a water vapor transmission cup, with 3 parallel samples per group. Distilled water was filled into the water vapor transmission cup, and the sample was sealed and fixed at the mouth of the cup to ensure no leakage or wrinkles. The water vapor transmission cup was placed in a constant temperature and humidity chamber (temperature 38℃, relative humidity 98%). After stabilization, timing was started. After 24 hours, the water vapor transmission cup was removed, and the total mass of the cup was accurately weighed. The water vapor transmission rate was calculated based on the change in mass. WVTR=(Δm×24) / (A×t); WVTR: Water vapor transmission rate, g / (m²) 2 .24h); Δm: Mass loss of the permeate cup within 24 hours, in grams; A: Effective transmittance area of ​​the sample, m 2 ; t: Experiment duration, h.

[0034] (3) Antibacterial properties: Referring to standard JIS Z2801, the antibacterial rate of the pipes prepared in Examples 1-3 and Comparative Examples 1-6 against Staphylococcus aureus and Escherichia coli was tested.

[0035] To verify that the mechanical properties of the oxygen delivery tubing of the present invention can meet normal use, oxygen delivery tubing samples were prepared using the methods of Examples 1-3 respectively. Then, under room temperature and heating (75°C) conditions, the tensile strength of the medical water-permeable and air-permeable breathing tubing obtained in Examples 1-3 of the present invention was measured in accordance with the national standard GB / T1040.1-2018. The results are shown in Table 1.

[0036] As shown in Table 1, the oxygen delivery pipe of this invention has a tensile strength of over 26 MPa at room temperature, which is sufficient for normal use. Although its mechanical properties decrease under heating (75°C) conditions, they still reach over 23 MPa, which is also sufficient for normal use.

[0037] Next, oxygen delivery pipes were processed using the methods provided in Examples 1-3 and Comparative Examples 1-6, respectively. Then, their performance was tested according to the test methods (1)-(3) above, and the results are shown in Table 2.

[0038] Table 2 The oxygen delivery pipe was spirally wound with a heating guide wire on its outer spiral support wall to heat the oxygen delivery pipe. The heating temperature was controlled at 75°C. Then, the above performance test was carried out again under constant temperature conditions. The results are shown in Table 3.

[0039] Table 3 As shown in Tables 2 and 3, the oxygen delivery pipe of this invention exhibits excellent water permeability and air impermeability at room temperature. Furthermore, under heating conditions, its water vapor permeability significantly increases without affecting its air impermeability. In the preparation process of the water-permeable and air-impermeable polyester film of the oxygen delivery pipe of this invention, titanium dioxide nanowires are grown on the surface of the hollow porous nanofiber membrane. The cross-linked network structure formed by the intertwining of the nanowires can restrict the expansion of the fiber membrane, effectively inhibiting excessive expansion of the hollow channels inside the fiber under heat, reducing the squeezing effect of the fiber on the surrounding polyurethane matrix, stabilizing the overall dense structure of the polyurethane film, and preventing air permeability and a sharp increase in water vapor permeability. This plays a decisive role in the normal use of the oxygen delivery pipe under heating conditions.

[0040] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A water-permeable but air-impermeable oxygen transport pipe, characterized in that, The oxygen delivery pipe has a double-layer structure, with the inner layer being a water-permeable but air-impermeable polyester film and the outer layer being a spiral-supported pipe wall. The water-permeable but air-permeable polyester film is prepared by adding an antibacterial agent solution to a polyurethane solution to obtain an antibacterial polyurethane solution. Then, a composite nanofiber membrane is stacked by a layer-by-layer rotational misalignment method. The antibacterial polyurethane solution is uniformly impregnated into the gaps between the multi-layer stacked composite nanofiber membranes using a micro-coating method, and then cured at low temperature. The spiral support tube wall is made of medical-grade thermoplastic polyurethane material.

2. The water-permeable but air-impermeable oxygen transport pipe according to claim 1, characterized in that, The water-permeable but air-permeable polyester film is prepared by the following method: 1) Add polyurethane particles to a solvent and stir slowly at 60-65℃ until completely dissolved to obtain a polyurethane solution. Then add medical quaternary ammonium antibacterial agent to the solvent and stir thoroughly at room temperature to obtain an antibacterial agent stock solution. Then slowly add the antibacterial agent stock solution to the polyurethane solution and stir slowly to obtain an antibacterial polyurethane solution. 2) Select 3-5 composite nanofiber membranes and stack them in a staggered, rotating manner, with the angle between adjacent layers of fiber membranes offset by 30°-60°. Then, gently press them to make the fiber membranes stack tightly. Next, use a micro-coating method to uniformly impregnate the antibacterial polyurethane solution into the gaps between the multilayer stacked fiber membranes. Place the impregnated membrane in a low-temperature, slow-curing environment of 40-50°C for 25-35 minutes, and allow it to cool naturally before demolding to obtain a water-permeable but air-permeable polyester film.

3. The oxygen transport pipe according to claim 2, characterized in that, The polyurethane particles are made of polyether-type thermoplastic polyurethane elastomer, with soft segments accounting for 50-80% and hard segments accounting for 20-50%. The solvent is obtained by mixing anhydrous ethanol and deionized water in a volume ratio of (7-8):(2-3); The polyurethane solution has a concentration of 5-8 wt%. The concentration of the antibacterial agent stock solution is 3-5 wt%. The antibacterial polyurethane solution contains an antibacterial agent at a concentration of 0.5-1.0 wt% of the polyurethane solids content.

4. The method for preparing a water-permeable but air-impermeable oxygen transport pipe according to claim 2, characterized in that, The composite nanofiber membrane is prepared by the following method: 1) After purging the hollow porous nanofiber membrane with anhydrous ethanol, let it stand at room temperature for 10-20 min to obtain a pretreated fiber membrane. Then, after stirring and mixing deionized water and anhydrous ethanol, add glacial acetic acid, stir thoroughly, and slowly add tetrabutyl titanate dropwise. After the dropwise addition is complete, stir thoroughly to obtain the precursor reaction solution. 2) Place the pretreated fiber membrane flat and suspended in the middle of the lining of the hydrothermal reactor. Then slowly pour the precursor reaction solution into the lining to completely immerse the pretreated fiber membrane. Let it stand for 10-20 minutes to soak. Seal the hydrothermal reactor and react at a constant temperature for 2-3 hours. After the reaction is complete, let it cool naturally to room temperature. Slowly remove the fiber membrane and rinse it repeatedly with anhydrous ethanol and deionized water. Then dry it in an oven for 60-100 minutes.

5. The method for preparing a water-permeable but air-impermeable oxygen transport pipe according to claim 4, characterized in that, In the precursor reaction solution, the volume ratio of deionized water, anhydrous ethanol, glacial acetic acid, and tetrabutyl titanate is (5-10):(35-70):(2-4):(1.2-2.4). The isothermal reaction is carried out at a temperature of 90-95℃. The drying process takes place at a temperature of 40-45℃.

6. The method for preparing a water-permeable but air-impermeable oxygen transport pipe according to claim 1, characterized in that, The hollow porous nanofiber membrane is prepared by the following method: 1) Add polyurethane particles to a mixed solvent consisting of N,N-dimethylformamide and tetrahydrofuran, place it in a constant temperature water bath at 50-55℃ and stir magnetically for 4-6 hours, then add polyethylene glycol and continue stirring for 2-3 hours. Let it stand at room temperature for 1-3 hours to remove bubbles and obtain the shell spinning solution. 2) Mix Tween 80 evenly into mineral oil and stir magnetically for 30-50 minutes at room temperature to obtain core spinning solution. Then, at room temperature and relative humidity of 40-50%, perform coaxial electrospinning using a dual-channel coaxial needle. Add micro nozzles symmetrically on both sides of the coaxial nozzle and introduce dry low-pressure nitrogen gas of 0.08-0.15MPa, sweeping it laterally across the spinning jet. After spinning is completed, obtain nanofiber membrane. 3) Immerse the nanofiber membrane obtained by spinning completely in n-hexane solution and extract in a sealed container at room temperature for 36-40 hours. After extraction, remove the nanofiber membrane, air dry it at room temperature, place it in a drying oven, anneal it at a constant temperature for 1-2 hours, and then cool it naturally to room temperature.

7. The method for preparing a water-permeable but air-impermeable oxygen transport pipe according to claim 6, characterized in that, In step 1), the mass ratio of polyurethane particles, polyethylene glycol, and mixed solvent in the shell spinning solution is (12-15):(4-7):(80-85). The polyurethane particles are made of polyether-type thermoplastic polyurethane elastomer, with soft segments accounting for 50-80% and hard segments accounting for 20-50%. The mixed solvent is composed of N,N-dimethylformamide and tetrahydrofuran in a volume ratio of (6-7):(3-4).

8. The method for preparing a water-permeable but air-impermeable oxygen transport pipe according to claim 6, characterized in that, In step 2), the mass ratio of Tween 80 to mineral oil in the core spinning solution is (0.5-0.8):(99.2-99.5). The electrospinning process has the following specific parameters: spinning voltage 14-18kV, receiving distance 15-20cm, shell liquid flow rate 1.0-1.3mL / h, and core liquid flow rate 0.2-0.4mL / h.

9. The method for preparing a water-permeable but air-impermeable oxygen transport pipe according to claim 6, characterized in that, In step 3), during the extraction, the n-hexane is replaced every 8-10 hours; The isothermal annealing is performed at a temperature of 70-75℃.

10. A method for preparing a water-permeable but air-impermeable oxygen transport pipe, characterized in that, The specific preparation method is as follows: First, a water-permeable but air-permeable polyester film is rolled into a cylindrical inner layer film. Then, polyurethane granules are fed into a screw extruder to obtain a spiral tubular structure, which is then wrapped and adhered to the outer surface of the cylindrical inner layer film. After shaping and cutting, an oxygen transmission pipe can be obtained.

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