Hydrophilic lubricating polyurethane medical intervention catheter and preparation method thereof

Abstract

The invention discloses a hydrophilic lubricating polyurethane medical interventional catheter and a preparation method thereof, belongs to the technical field of medical interventional instruments, and aims to solve the problems that an existing interventional catheter is difficult to consider both lubricating adaptability and mechanical property, insufficient in interlayer adhesive force and free of synergistic effect, and lubricating durability and activation speed are difficult to balance. Comprising a polyurethane catheter base body, and the outer surface of the polyurethane catheter base body is sequentially coated with a base layer, a function adaptive middle layer and a universal pre-soaking surface layer. According to the invention, a hydrophilic resin-functional filler composite cross-linked structure is adopted to design a functional adaptive middle layer, and through targeted type selection and accurate matching of the functional filler, the coordination of scene lubrication adaptation and mechanical property enhancement is realized, for example, surface modified nano-hydroxyapatite is selected in a vascular intervention scene, the hydrophilic surface of the surface modified nano-hydroxyapatite can inhibit protein adhesion, and the mechanical property of the surface modified nano-hydroxyapatite is enhanced. Meanwhile, the hardness of the coating is improved by more than 30%.

Description

Technical Field

[0001] This invention relates to the field of medical interventional device technology, specifically to a hydrophilic lubricated polyurethane medical interventional catheter and its preparation method. Background Technology

[0002] Interventional catheters are indispensable core devices in interventional therapy, widely used in various clinical scenarios such as angiography, stent implantation, interventional oncology, and urinary drainage. Their performance directly affects the safety and effectiveness of the procedure. Polyurethane (PU) has become the mainstream material for the substrate of interventional catheters due to its excellent biocompatibility, flexibility, and mechanical strength. To reduce frictional damage between the catheter and the mucous membranes of blood vessels, esophagus, urethra, and other tissues during catheter intervention and to reduce the risk of complications, a hydrophilic lubricating coating is usually applied to the surface of the polyurethane catheter substrate. This type of coating can quickly absorb water and swell upon contact with bodily fluids such as blood and urine to form a hydrated lubricating film, thereby reducing the coefficient of friction.

[0003] Currently, most existing hydrophilic lubricating polyurethane conduits adopt a double-layer coating structure of "base layer + single absorbent layer". The base layer is used to ensure the adhesion between the coating and the polyurethane matrix, while the single absorbent layer is used to achieve the hydrophilic lubrication function.

[0004] However, clinical interventional scenarios are complex and diverse, and the characteristics of the media that the catheter contacts vary significantly in different scenarios. For example, blood in vascular intervention scenarios contains a large amount of protein and red blood cells, mucosal secretions in esophageal / gastrointestinal intervention scenarios contain highly viscous mucoproteins, urine in urinary intervention scenarios contains urea and electrolytes, and exudate in drainage scenarios has a complex composition and large viscosity fluctuations. The existing double-layer coating structure adopts a general-purpose absorbent layer design, which not only cannot be specifically adapted to different media characteristics, but also has the following core defects: 1. It is difficult to balance lubrication compatibility and mechanical properties. Existing single hydrophilic coatings have low mechanical strength in order to ensure water absorption and lubrication. They are prone to wear during pushing and friction, and cannot specifically solve scenario-specific problems such as protein adhesion and mucus blockage. 2. Insufficient interlayer adhesion and lack of synergistic effect. Different coating materials are simply coated and stacked without interfacial chemical bonding or gradient transition structure. They are prone to interlayer peeling during pushing, twisting or long-term immersion. The detached coating fragments may cause serious complications such as vascular embolism and tissue inflammation. 3. It is difficult to balance lubrication durability and activation speed. The crosslinking degree of a single coating cannot simultaneously meet the requirements of "rapid water absorption and activation" and "long-term lubrication stability". 4. The preparation process is crude. The existing process only controls the coating and curing parameters in a simple way, without designing special processes for key links such as "dispersion of functional fillers" and "synergistic cross-linking between layers", resulting in unstable coating performance and low yield. Summary of the Invention

[0005] To overcome the above problems, this invention aims to propose a hydrophilic lubricating polyurethane medical interventional catheter and its preparation method, with the purpose of solving the problems of difficulty in balancing lubrication adaptability and mechanical properties, insufficient interlayer adhesion and lack of synergistic effect, and difficulty in balancing lubrication durability and activation speed in current interventional catheters.

[0006] Therefore, the specific technical solution adopted by the present invention is as follows: According to one aspect of the present invention, a hydrophilic lubricating polyurethane medical interventional catheter is provided, comprising a polyurethane catheter matrix, wherein the outer surface of the polyurethane catheter matrix is ​​sequentially coated with a base layer, a functional adaptation intermediate layer, and a universal pre-soaking surface layer; the functional adaptation intermediate layer is a "hydrophilic resin-functional filler" composite cross-linked structure designed for the media characteristics of different clinical interventional scenarios; the universal pre-soaking surface layer is a low-crosslinking degree hydrophilic resin layer; and the functional adaptation intermediate layer and the universal pre-soaking surface layer form a gradient cross-linked structure through an interpenetrating polymer network (IPN); the base layer and the functional adaptation intermediate layer achieve interface fusion through chemical bonding, which is used for unified pre-soaking activation before clinical use and to ensure long-term lubrication stability in various scenarios.

[0007] Optionally, the base layer is a mixture of polyurethane modified resin and polyetheramine coupling agent, and the thickness of the base layer is 5-10 μm.

[0008] Optionally, the thickness of the functional adapter intermediate layer is 8-15 μm, and in the "hydrophilic resin-functional filler" composite cross-linking structure, the particle size of the functional filler is 20-100 nm, and it is classified into at least one of the following according to the clinical interventional scenario: (1) Vascular intervention scenario: The hydrophilic resin is a cross-linked polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) block copolymer, and the functional filler is surface-modified nano-hydroxyapatite. The mass ratio of hydrophilic resin to functional filler is 95:5~90:10. The functional filler is used to inhibit protein adhesion and enhance the mechanical strength of the coating. (2) Esophagus / gastrointestinal intervention scenario: The hydrophilic resin is a chitosan-polyethylene glycol (PEG) graft copolymer, the functional filler is carboxylated nanocellulose, and the mass ratio of hydrophilic resin to functional filler is 92:8~85:15. The functional filler is used to reduce mucus adhesion and improve the friction resistance of the coating. (3) Urinary intervention scenario: The hydrophilic resin is poly(hydroxyethyl methacrylate) (PHEMA), the functional filler is aminated nano-silica, and the mass ratio of hydrophilic resin to functional filler is 93:7~88:12. The functional filler is used to improve the coating's resistance to urine corrosion. (4) Drainage scenario: The hydrophilic resin is a blend of polyacrylic acid (PAA) and polyvinylpyrrolidone (PVP), and the functional filler is nano-montmorillonite. The mass ratio of hydrophilic resin to functional filler is 94:6~89:11. The functional filler is used to adapt to exudates of different viscosities and enhance the stability of the coating structure.

[0009] Optionally, the material of the general pre-soaked surface layer is low-crosslinked polyvinylpyrrolidone (PVP), with the crosslinking degree controlled at 15%-20% and the thickness at 5-10 μm; in the gradient crosslinking structure, the crosslinking degree of the functional adaptation intermediate layer is 40%-60%, and the crosslinking degree gradually decreases from the functional adaptation intermediate layer to the general pre-soaked surface layer, which is used for the synergy of rapid activation and long-term lubrication.

[0010] Optionally, the base layer is a mixture of polyurethane modified resin and polyetheramine coupling agent, and the thickness of the base layer is 5-10 μm; the chemical bonding is achieved by the base layer and the functionally adapted intermediate layer sharing an isocyanate crosslinking agent, and the amount of polyetheramine coupling agent added is 5%-15% of the mass of polyurethane modified resin, which is used to enhance the interfacial bonding force.

[0011] Optionally, a method for preparing a hydrophilic lubricated polyurethane medical interventional catheter is characterized by comprising the following steps: S1: Surface pretreatment of polyurethane conduit matrix; S2: The base coating is applied to the surface of the pretreated polyurethane conduit substrate by dip coating, and the base layer is obtained after semi-curing treatment; S3: Based on the target clinical intervention scenario, prepare a functional adaptation intermediate layer coating containing corresponding "hydrophilic resin-functional filler". Use ultrasonic dispersion combined with mechanical stirring to uniformly disperse the functional filler. The ultrasonic power is 150-200W and the dispersion time is 15-25min. Then, apply it to the base layer surface by dip coating. After low temperature plasma activation treatment and semi-curing treatment, the functional adaptation intermediate layer is obtained. After semi-curing, 30%-40% of the active functional groups in the coating are retained. S4: A general pre-soaked surface coating is applied to the surface of the functional adaptation intermediate layer by spraying, and the finished conduit is obtained by gradient temperature curing.

[0012] Optionally, in step S1, the surface pretreatment is plasma treatment with a power of 30-50W and a treatment time of 2-5 minutes.

[0013] Optionally, in steps S2 and S3, the temperature of the semi-curing treatment is 60-70℃ and the time is 5-8 minutes, and 30%-40% of the active functional groups in the coating are retained after the semi-curing treatment.

[0014] Optionally, in step S3, the surface activation treatment is a low-temperature plasma treatment with a treatment power of 20-30W and a treatment time of 1-2 minutes.

[0015] Optionally, in step S4, the process parameters for gradient temperature curing are: 60℃ for 10-15 min, 80℃ for 10-15 min, 100℃ for 5-10 min, and a total curing time of 30-60 min.

[0016] Compared with the prior art, this application has the following beneficial effects: This invention addresses the aforementioned deficiencies in existing hydrophilic lubricating polyurethane medical interventional catheters by proposing a multi-layer coating structure consisting of a "base layer + functionally compatible intermediate layer + universal pre-soaked surface layer" and a corresponding preparation method, which offers the following advantages: 1. This invention employs a "hydrophilic resin-functional filler" composite cross-linked structure design for a functionally adaptable intermediate layer. Through targeted selection and precise proportioning of functional fillers, it achieves synergy between "scenario-specific lubrication adaptation" and "enhanced mechanical properties." For example, in vascular intervention scenarios, surface-modified nano-hydroxyapatite is used, whose hydrophilic surface can inhibit protein adhesion and simultaneously increase coating hardness by more than 30%; in esophageal scenarios, carboxylated nano-cellulose is used, which can reduce mucus adhesion through hydrogen bonding and increase the number of friction cycles to more than 500 (existing coatings typically have ≤200 cycles); in urinary scenarios, aminated nano-silica is used, which can form a stable interaction with urea molecules in urine, preventing coating degradation; and in drainage scenarios, nano-montmorillonite is used, whose layered structure can adapt to the water absorption requirements of exudates of different viscosities, while enhancing the structural stability of the coating. This composite structure is not a simple material mixing, but rather a synergistic process of ultrasonic dispersion-semi-curing cross-linking, which allows the functional fillers to be uniformly dispersed and form a three-dimensional cross-linked network with the hydrophilic resin, achieving better technical results.

[0017] 2. This invention constructs a dual interface enhancement mechanism of "chemical bonding + IPN gradient crosslinking", which breaks through the limitations of existing simple coatings. The base layer and the functional adaptation intermediate layer achieve chemical bonding through a shared isocyanate crosslinking agent, ensuring no obvious delamination at the interface. The functional adaptation intermediate layer and the general pre-soaked surface layer form a gradient crosslinking structure through IPN technology, with the degree of crosslinking gradually decreasing from 40%-60% to 15%-20%. This ensures both interlayer molecular-level fusion (detachment rate ≤5%) and a gradient transition in lubrication performance. This structural design is based on the core requirements of "interface fusion" and "performance synergy", and is achieved through precise matching of material selection and process control. After testing, the catheter showed no obvious interlayer delamination even after repeated pushing, twisting, and long-term immersion in body fluids in simulated clinical operations, which is far superior to existing double-layer coatings.

[0018] 3. This invention achieves a precise balance between the two through a layered design. The general pre-soaking surface layer uses 15%-20% low-crosslinked PVP material to ensure rapid water absorption and swelling within 30 seconds of pre-soaking, meeting the needs of rapid clinical activation. The functional adaptation intermediate layer uses a highly crosslinked hydrophilic material to ensure long-term stable lubrication performance during long-term use. For example, after the catheter in the urinary intervention scenario is soaked in artificial urine for 7 days, the coefficient of friction is still ≤0.08, which can meet the needs of long-term indwelling.

[0019] 4. This invention employs a combined process of "plasma pretreatment + dip coating semi-curing + activation treatment + spray gradient curing". By precisely controlling the parameters of each step, it ensures uniform coating thickness and tight interlayer bonding. Specifically, plasma pretreatment enhances the surface activity of the substrate, ensuring a solid foundation for substrate adhesion; parameter control of the semi-curing process ensures sufficient interlayer cross-linking; gradient temperature curing avoids internal stress caused by rapid curing, which can lead to coating cracking; simultaneously, dip coating ensures uniform thickness for the substrate and intermediate layers, while spray coating precisely controls the thickness of the thin coating layer, keeping the total thickness of the multi-layer coating within 25-40 μm, ≤10% of the polyurethane conduit substrate wall thickness, without affecting the conduit's flexibility and delivery performance. The yield rate is increased by more than 30% compared to existing processes.

[0020] 5. All materials used in each layer of this invention are pharmacopoeia-grade medical hydrophilic materials, such as medical-grade PVP, PHEMA, chitosan, etc. At the same time, by strictly controlling residual monomers (such as PVP residual monomer NVP≤10ppm) and crosslinking agent residues, there is no cytotoxicity, hemolytic reaction and sensitization reaction, and it can be safely applied in clinical interventional scenarios. Attached Figure Description

[0021] The above-mentioned features, characteristics, and advantages of the present invention, as well as their implementation methods, will become clearer and more readily understood in conjunction with the following description of the embodiments, which are illustrated in detail with reference to the accompanying drawings. Schematic diagrams are shown here: Figure 1 This is a flowchart of a hydrophilic lubricated polyurethane medical interventional catheter and its preparation method according to an embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0023] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0024] Example 1: Preparation of a hydrophilic lubricated polyurethane medical interventional catheter for vascular intervention. The specific steps for preparing a vascular interventional catheter in this embodiment are as follows: S1: Select medical-grade TPU catheter substrate (hardness Shore 70D, wall thickness 0.4mm), perform plasma surface pretreatment, treatment power 40W, treatment time 3min, and use it for later use; S2: Preparation of base coating: Mix polyurethane modified resin and polyetheramine coupling agent at a mass ratio of 10:1, add N,N-dimethylformamide (DMF) solvent, and stir until completely dissolved to form a base coating with a solid content of 15%; apply the base coating to the surface of the pretreated TPU conduit substrate by dip coating at a dip coating speed of 5 mm / s, and then perform semi-curing treatment with process parameters of 65℃ for 6 min to obtain a base layer with a thickness of 8 μm; S3: Formulation of functional adaptation intermediate layer coating for vascular intervention scenarios: Cross-linked PVP and PEG block copolymer (hydrophilic resin) and surface-modified nano-hydroxyapatite (functional filler) are mixed at a mass ratio of 92:8. DMF solvent is added, and the mixture is first ultrasonically dispersed (power 180W, time 20min), then mechanically stirred for 30min. After that, isocyanate cross-linking agent is added (the amount added is 3% of the mass of the mixture) to form an intermediate layer coating with a solid content of 20%. The intermediate layer coating is applied to the surface of the base layer by dip coating at a dip coating speed of 3mm / s. Then, low-temperature plasma activation treatment is performed (power 25W, time 1.5min), followed by semi-curing treatment (holding at 65℃ for 6min) to obtain a functional adaptation intermediate layer with a thickness of 12μm. S4: Preparation of general pre-soaked surface coating: Select low crosslinking degree PVP (crosslinking degree 18%), add DMF solvent, stir to dissolve, and then add a small amount of isocyanate crosslinking agent (addition amount is 1% of PVP mass) to form a surface coating with a solid content of 10%; use spraying method to coat the surface coating onto the surface of the functional adaptation intermediate layer, spraying pressure 0.3MPa, spraying distance 15cm, and then perform gradient temperature rise curing treatment, process parameters are 60℃ for 12min → 80℃ for 12min → 100℃ for 8min, to obtain a general pre-soaked surface layer with a thickness of 8μm; finally, a hydrophilic lubricated polyurethane medical interventional catheter for vascular intervention with a total multilayer coating thickness of 28μm is obtained.

[0025] The catheter prepared in this embodiment was subjected to performance tests: the coefficient of friction was 0.04 after pre-soaking for 30 seconds; after soaking in bovine serum albumin (BSA) for 2 hours, the protein adhesion amount was 3.2 μg / cm²; after repeated pushing in a simulated vascular environment for 50 times, the coefficient of friction was still 0.06; after soaking in artificial blood for 7 days, the coating peeling rate was 2.1%; according to the ISO 10993 series tests, it showed no cytotoxicity, hemolysis rate ≤1.5%, and no sensitization reaction, meeting the requirements for medical use.

[0026] Example 2: Preparation of hydrophilic lubricated polyurethane medical interventional catheter for urological intervention. The specific steps for preparing a catheter for urological interventional procedures in this embodiment are as follows: S1: Select medical-grade TPU catheter substrate (hardness Shore 65D, wall thickness 0.5mm), perform plasma surface pretreatment, treatment power 35W, treatment time 4min, and use it for later use; S2: Prepare the base coating and apply the semi-cured coating: Same as step S2 in Example 1, to obtain a base layer with a thickness of 7μm; S3: Formulation of functional adaptation intermediate layer coating for urological intervention scenarios: PHEMA (hydrophilic resin) and aminated nano-silica (functional filler, particle size 50nm) were mixed at a mass ratio of 90:10, DMF solvent was added, and the mixture was ultrasonically dispersed (power 160W, time 22min) and mechanically stirred for 30min. Then, isocyanate crosslinking agent (addition amount is 4% of the mass of the mixture) was added to form an intermediate layer coating with a solid content of 22%. The coating was applied by dip coating (dip coating speed 4mm / s), followed by low-temperature plasma activation treatment (power 22W, time 2min) and semi-curing treatment (holding at 65℃ for 7min) to obtain a functional adaptation intermediate layer with a thickness of 14μm. S4: Preparation of general pre-soaked surface coating and coating curing: Same as step S4 in Example 1, to obtain a general pre-soaked surface with a thickness of 7μm; finally, a hydrophilic lubricated polyurethane medical interventional catheter for urological intervention with a total multilayer coating thickness of 28μm is obtained.

[0027] The catheter prepared in this embodiment was subjected to performance tests: after pre-soaking for 30 seconds, the coefficient of friction was 0.05; after soaking in artificial urine for 7 days, the coefficient of friction was 0.07 and the coating peeling rate was 2.8%; after soaking for 14 days, the coefficient of friction was 0.09 and the coating peeling rate was 3.5%; according to the ISO 10993 series tests, it showed no cytotoxicity, hemolysis rate ≤1.2%, and no sensitization reaction, which can meet the requirements for long-term indwelling.

[0028] Example 3: Preparation of a hydrophilic lubricated polyurethane medical interventional catheter for esophageal intervention The specific steps for preparing the esophageal interventional catheter in this embodiment are as follows: S1: Select medical-grade TPU catheter substrate (hardness Shore 60D, wall thickness 0.3mm), perform plasma surface pretreatment, treatment power 45W, treatment time 2.5min, and use it for later use; S2: Prepare the base coating and apply the semi-cured coating: Same as step S2 in Example 1, to obtain a base layer with a thickness of 6μm; S3: Formulation of functional adaptation intermediate layer coating for esophageal intervention scenario: Chitosan-PEG graft copolymer (hydrophilic resin) and carboxylated nanocellulose (functional filler, particle size 80nm) were mixed at a mass ratio of 88:12. A DMF and water mixture was added at a volume ratio of 1:1. After ultrasonic dispersion (power 190W, time 18min) and mechanical stirring for 30min, glutaraldehyde crosslinking agent (addition amount is 2% of the mass of the mixed resin) was added to form an intermediate layer coating with a solid content of 18%. The coating was applied by dip coating method (dip coating speed 3.5mm / s), followed by low temperature plasma activation treatment (power 28W, time 1min) and semi-curing treatment (holding at 65℃ for 5min) to obtain a functional adaptation intermediate layer with a thickness of 10μm. S4: Preparation of general pre-soaked surface coating and coating curing: Same as step S4 in Example 1, to obtain a general pre-soaked surface with a thickness of 6μm; finally, a hydrophilic lubricated polyurethane medical interventional catheter for esophageal intervention with a total multilayer coating thickness of 22μm is obtained.

[0029] The catheter prepared in this embodiment was subjected to performance tests: after pre-soaking for 30 seconds, the coefficient of friction was 0.05; after soaking in pig gastric mucus for 2 hours, the amount of mucus adhering was 7.5 μg / cm²; after repeated friction in a simulated esophageal environment for 50 cycles, the coefficient of friction was 0.08; according to the ISO 10993 series tests, it showed no cytotoxicity, hemolysis rate ≤1.0%, and no sensitization reaction, meeting the requirements for use in esophageal intervention.

[0030] Example 4: Preparation of a hydrophilic lubricated polyurethane medical interventional catheter for drainage. The specific steps for preparing a catheter for a drainage scenario in this embodiment are as follows: S1: Select medical-grade TPU catheter substrate (hardness Shore 75D, wall thickness 0.45mm), perform plasma surface pretreatment, treatment power 42W, treatment time 3.5min, and use it for later use; S2: Prepare the base coating and apply the semi-cured coating: Same as step S2 in Example 1, to obtain a base layer with a thickness of 9μm; S3: Formulation of the functional adaptation intermediate layer coating for the drainage scenario: PAA-PVP blend (hydrophilic resin, PAA to PVP mass ratio 6:4) and nano-montmorillonite (functional filler, particle size 60nm) are mixed at a mass ratio of 91:9. DMF solvent is added, and the mixture is first ultrasonically dispersed (power 170W, time 23min), then mechanically stirred for 30min. After that, isocyanate crosslinking agent is added (addition amount is 3.5% of the mass of the mixture) to form an intermediate layer coating with a solid content of 21%. The intermediate layer coating is applied to the surface of the base layer by dip coating at a dip coating speed of 3.8mm / s. Then, low-temperature plasma activation treatment is performed (power 26W, time 1.8min), followed by semi-curing treatment (65℃ for 6.5min) to obtain a functional adaptation intermediate layer with a thickness of 13μm. S4: Preparation of general pre-soaked surface coating and coating curing: Same as step S4 in Example 1, to obtain a general pre-soaked surface coating with a thickness of 9μm; finally, a hydrophilic lubricated polyurethane medical interventional catheter for drainage scenarios with a total multi-layer coating thickness of 31μm is obtained.

[0031] The catheter prepared in this embodiment was subjected to performance tests: after pre-soaking for 30 seconds, the coefficient of friction was 0.05; after soaking in simulated exudates of low viscosity (1 mPa·s), medium viscosity (5 mPa·s), and high viscosity (10 mPa·s) for 1 hour, the water absorption and swelling time was ≤45 seconds, and the coefficients of friction were 0.04, 0.05, and 0.06, respectively, showing excellent media compatibility; after being dynamically flushed by simulated body fluid for 30 minutes, the lubricity did not decrease significantly, and the coefficient of friction was still ≤0.07; after soaking in simulated exudate for 14 days, the coating peeling rate was 3.2%; according to the ISO 10993 series tests, there was no cytotoxicity, the hemolysis rate was ≤1.3%, and there was no sensitization reaction, which meets the requirements for use in drainage scenarios.

[0032] The above embodiments are merely preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the core principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0033] Although the present invention has been disclosed above with reference to preferred embodiments, the embodiments are merely examples for illustrative purposes and are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. The scope of protection claimed by the present invention should be determined by the claims.

Claims

1. A hydrophilic lubricating polyurethane medical interventional catheter, comprising a polyurethane catheter matrix, characterized in that, The outer surface of the polyurethane catheter matrix is ​​sequentially coated with a base layer, a functional adaptation intermediate layer, and a universal pre-soaking surface layer. The functional adaptation intermediate layer is a "hydrophilic resin-functional filler" composite cross-linked structure designed for the characteristics of media in different clinical intervention scenarios. The universal pre-soaking surface layer is a low-crosslinked hydrophilic resin layer. The functional adaptation intermediate layer and the universal pre-soaking surface layer form a gradient cross-linked structure through an interpenetrating polymer network (IPN). The base layer and the functional adaptation intermediate layer achieve interface fusion through chemical bonding. This is used for unified pre-soaking activation before clinical use and to ensure long-term lubrication stability in various scenarios.

2. The hydrophilic lubricated polyurethane medical interventional catheter according to claim 1, characterized in that, The base layer is a mixture of polyurethane modified resin and polyetheramine coupling agent, and the thickness of the base layer is 5-10 μm.

3. The hydrophilic lubricated polyurethane medical interventional catheter according to claim 1, characterized in that, The thickness of the functional adapter intermediate layer is 8-15 μm, and in the "hydrophilic resin-functional filler" composite cross-linking structure, the particle size of the functional filler is 20-100 nm, and it is classified into at least one of the following according to the clinical interventional scenario: (1) Vascular intervention scenario: The hydrophilic resin is a cross-linked polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) block copolymer, and the functional filler is surface-modified nano-hydroxyapatite. The mass ratio of hydrophilic resin to functional filler is 95:5~90:

10. The functional filler is used to inhibit protein adhesion and enhance the mechanical strength of the coating. (2) Esophagus / gastrointestinal intervention scenario: The hydrophilic resin is a chitosan-polyethylene glycol (PEG) graft copolymer, the functional filler is carboxylated nanocellulose, and the mass ratio of hydrophilic resin to functional filler is 92:8~85:

15. The functional filler is used to reduce mucus adhesion and improve the friction resistance of the coating. (3) Urinary intervention scenario: The hydrophilic resin is poly(hydroxyethyl methacrylate) (PHEMA), the functional filler is aminated nano-silica, and the mass ratio of hydrophilic resin to functional filler is 93:7~88:

12. The functional filler is used to improve the coating's resistance to urine corrosion. (4) Drainage scenario: The hydrophilic resin is a blend of polyacrylic acid (PAA) and polyvinylpyrrolidone (PVP), and the functional filler is nano-montmorillonite. The mass ratio of hydrophilic resin to functional filler is 94:6~89:

11. The functional filler is used to adapt to exudates of different viscosities and enhance the structural stability of the coating.

4. The hydrophilic lubricated polyurethane medical interventional catheter according to claim 1, characterized in that, The material of the general pre-soaked surface layer is low-crosslinked polyvinylpyrrolidone (PVP), with the crosslinking degree controlled at 15%-20% and the thickness at 5-10 μm; in the gradient crosslinking structure, the crosslinking degree of the functional adaptation intermediate layer is 40%-60%, and the crosslinking degree gradually decreases from the functional adaptation intermediate layer to the general pre-soaked surface layer, which is used for the synergy of rapid activation and long-term lubrication.

5. The hydrophilic lubricated polyurethane medical interventional catheter according to claim 1, characterized in that, The base layer is a mixture of polyurethane modified resin and polyetheramine coupling agent, and the thickness of the base layer is 5-10 μm. The chemical bonding is achieved by sharing an isocyanate crosslinking agent between the base layer and the functionally adapted intermediate layer. The amount of polyetheramine coupling agent added is 5%-15% of the mass of the polyurethane modified resin, which is used to enhance the interfacial bonding force.

6. A method for preparing a hydrophilic lubricated polyurethane medical interventional catheter as described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Surface pretreatment of polyurethane conduit matrix; S2: The base coating is applied to the surface of the pretreated polyurethane conduit substrate by dip coating, and the base layer is obtained after semi-curing treatment; S3: Based on the target clinical intervention scenario, formulate a functional adaptation intermediate layer coating containing corresponding "hydrophilic resin-functional filler". Use ultrasonic dispersion combined with mechanical stirring to uniformly disperse the functional filler. The ultrasonic power is 150-200W and the dispersion time is 15-25min. Then, apply it to the surface of the base layer by dip coating. After low temperature plasma activation treatment and semi-curing treatment, the functional adaptation intermediate layer is obtained. After semi-curing, 30%-40% of the active functional groups in the coating are retained. S4: A general pre-soaked surface coating is applied to the surface of the functional adaptation intermediate layer by spraying, and the finished conduit is obtained by gradient temperature curing.

7. The method for preparing a hydrophilic lubricated polyurethane medical interventional catheter according to claim 6, characterized in that, In step S1, the surface pretreatment is plasma treatment with a power of 30-50W and a treatment time of 2-5 minutes.

8. The method for preparing a hydrophilic lubricated polyurethane medical interventional catheter according to claim 6, characterized in that, In steps S2 and S3, the temperature of the semi-curing treatment is 60-70℃ and the time is 5-8 minutes. After the semi-curing treatment, 30%-40% of the active functional groups in the coating are retained.

9. The method for preparing a hydrophilic lubricated polyurethane medical interventional catheter according to claim 6, characterized in that, In step S3, the surface activation treatment is a low-temperature plasma treatment with a power of 20-30W and a treatment time of 1-2 minutes.

10. The method for preparing a hydrophilic lubricated polyurethane medical interventional catheter according to claim 6, characterized in that, In step S4, the process parameters for gradient temperature curing are: 60℃ for 10-15 min, 80℃ for 10-15 min, 100℃ for 5-10 min, and a total curing time of 30-60 min.

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