Medical catheter braided reinforcing fiber and method of making same

Abstract

The application provides a medical catheter braided reinforcing fiber and a preparation method thereof, and relates to the technical field of medical catheter materials, and comprises a fiber core layer, the fiber core layer is composed of polymer long filament bundles, the tensile strength of the polymer long filament bundles is not less than 1.0 GPa, and an interface modification layer, the interface modification layer is arranged on the surface of the fiber core layer, and the interface modification layer contains a polar functional group. The application constructs a multilayer composite structure of a high-strength polymer long filament bundle fiber core layer, an interface modification layer containing a polar functional group and a thermoplastic adhesive coating layer, improves the interface bonding strength between the core layer and the coating layer on the basis of ensuring that the tensile strength of the fiber body is not less than 1.0 GPa, and realizes the unity of high strength, good interface bonding and braiding processability. Meanwhile, under the premise of not introducing metal wires and ferromagnetic metal components, the reinforcing fiber meets the safety requirements of medical catheters in a magnetic resonance environment, and also meets the X-ray developing requirements.

Description

Technical Field

[0001] This invention relates to the field of medical catheter materials technology, specifically to a braided reinforcing fiber for medical catheters and its preparation method. Background Technology

[0002] Medical catheters often employ a multi-layered composite tubular structure, typically including an inner liner, a reinforcing layer, and an outer sheath. To meet requirements for pressure resistance, kinking resistance, torque transmission, and delivery, the reinforcing layer often utilizes a braided structure. Adjusting the braiding angle and density enhances the tubular strength and morphological stability. Existing braided reinforcing materials mainly include two categories: metal wires and polymer fibers. Common metal wires include stainless steel wire and nickel-titanium alloy wire. Common polymer fibers include polyester, nylon, aramid, ultra-high molecular weight polyethylene, and liquid crystal polymers, which are combined with extrusion coating, hot-melt lamination, and other processes to form the braided reinforcing layer.

[0003] Existing technologies still have shortcomings: the metal reinforcement layer occupies wall thickness space, reduces the flexibility of the catheter, fatigue wire breakage is prone to occur in the bending area, the end or broken wire may form a sharp point and bring safety hazards, and there are compatibility and artifact risks in imaging examination scenarios. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a medical catheter braided reinforcing fiber and its preparation method. The technical problem this invention aims to solve is: how to address the issues of metal reinforcement layer occupying wall thickness, easy fatigue and fiber breakage, and imaging compatibility risks through a preparation process involving the construction of a high-strength polymer core layer, interface activation, and non-magnetic imaging thermoplastic coating.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a medical catheter braided reinforcing fiber, comprising: Fiber core layer: The fiber core layer is composed of polymer filament bundles, and the tensile strength of the polymer filament bundles is not less than 1.0 GPa; Interface modification layer: The interface modification layer is disposed on the surface of the fiber core layer, and the interface modification layer contains polar functional groups; Thermoplastic adhesive coating layer: The thermoplastic adhesive coating layer covers the interface modified layer. The material of the thermoplastic adhesive coating layer is selected from one or more of polyether block amide, thermoplastic polyurethane, and polyamide. The braided reinforcing fiber does not contain metal wires or ferromagnetic metal components. The outer diameter of the braided reinforcing fiber is 20μm-120μm. The thickness of the thermoplastic adhesive coating layer is 0.5μm-10μm.

[0006] The present invention is further configured such that the polymer filament bundle is selected from one or more of ultra-high molecular weight polyethylene filament bundle, aramid filament bundle, and liquid crystal polymer filament bundle, and the linear density of the polymer filament bundle is 50 dtex-300 dtex.

[0007] The present invention is further configured such that the thermoplastic adhesive coating layer contains a non-magnetic developing filler, the non-magnetic developing filler being barium sulfate or zirconium oxide, the particle size of the non-magnetic developing filler being 0.1μm-2μm, and the mass fraction being 5wt%-30wt%.

[0008] A method for preparing braided reinforcing fibers for medical catheters, comprising: S1. Provide a polymer filament bundle, wherein the tensile strength of the polymer filament bundle is not less than 1.0 GPa, use the polymer filament bundle as a fiber core layer, and clean and dry the fiber core layer to obtain the fiber core layer to be modified. S2. The fiber core layer to be modified is subjected to surface activation treatment, wherein the surface activation treatment is plasma treatment or chemical oxidation treatment, so that an interface modification layer containing polar functional groups is formed on the surface of the fiber core layer to be modified. S3. Select one or more of polyether block amide, thermoplastic polyurethane, and polyamide as the base resin for the thermoplastic adhesive coating layer and melt-blend to obtain the coating material. When X-ray development is required, add a non-magnetic developing filler to the coating material and mix evenly. The non-magnetic developing filler is barium sulfate or zirconium oxide with a particle size of 0.1μm-2μm and a mass fraction of 5wt%-30wt%. S4. Using a melt extrusion coating process, the coating material is coated on the outside of the interface modification layer, the thickness of the thermoplastic adhesive coating layer is controlled to be 0.5μm-10μm, and the outer diameter of the woven reinforcing fiber after forming is controlled to be 20μm-120μm. After cooling and forming, the shaped fiber is obtained. S5. The shaped fiber is heat-set and wound up to obtain medical catheter braided reinforcing fiber.

[0009] The present invention is further configured such that the cleaning and drying includes: cleaning with an organic solvent and rinsing with deionized water, wherein the organic solvent is isopropanol; after cleaning, drying is performed at 40℃-80℃ for 20min-50min, or drying is performed under a vacuum degree not higher than 20kPa for 20min-50min.

[0010] The present invention is further configured such that the plasma treatment uses oxygen plasma or air plasma, with a treatment power of 50W-300W, a treatment time of 10s-180s, and a treatment chamber pressure of 10Pa-200Pa.

[0011] The present invention is further configured such that the chemical oxidation treatment uses a hydrogen peroxide solution or a potassium permanganate solution; the hydrogen peroxide solution has a mass fraction of 5wt%-30wt% and a treatment time of 3min-15min; the potassium permanganate solution has a mass fraction of 0.1wt%-5wt% and a treatment time of 1min-10min; after treatment, the solution is rinsed with deionized water and dried.

[0012] The present invention is further configured such that the melt mixing is performed using a twin-screw extruder, the melt mixing temperature of the matrix resin is 160℃-240℃, and the screw speed is 50rpm-300rpm; the non-magnetic developing filler is dried at 80℃-120℃ for 1h-6h before being added.

[0013] The present invention is further configured such that the extrusion temperature of the melt extrusion coating process is 160℃-240℃, a traction tension of 0.1N-2N is applied to the fiber core layer during coating, the thermoplastic adhesive coating layer continuously covers the fiber circumferentially, and the cooling temperature is 10℃-30℃.

[0014] The present invention is further configured such that the heat setting treatment is carried out at 90℃-125℃ for 2min-10min; and during the heat setting treatment, a constant tension of 0.2N-1.0N is applied to the shaped fiber, and the winding tension is 0.2N-0.8N.

[0015] The beneficial effects of this invention are as follows: By constructing a multi-layer composite structure consisting of a high-strength polymer filament bundle fiber core layer, an interface-modified layer containing polar functional groups, and a thermoplastic adhesive coating layer, this invention improves the interfacial bonding strength between the core layer and the coating layer while ensuring that the tensile strength of the fiber body is not less than 1.0 GPa. This achieves a balance between high strength, good interfacial bonding, and weavable processing performance. Simultaneously, without introducing metal wires or ferromagnetic metal components, the reinforcing fiber meets the safety requirements of medical catheters in magnetic resonance imaging and also accommodates the imaging requirements under X-rays.

[0016] An interface modification layer containing polar functional groups is formed on the fiber surface using plasma or chemical oxidation, which enhances surface activity and interfacial wettability. Polyether block amide, thermoplastic polyurethane, or polyamide is used as the thermoplastic adhesive coating matrix, and non-magnetic radiopaque fillers such as barium sulfate or zirconium oxide are introduced. This ensures the continuous density and good flexibility of the coating layer while improving the bonding strength between the coating layer and the core layer and the overall structural stability. By controlling the coating thickness, outer diameter, and heat setting tension parameters, the dimensional stability and braiding consistency of the fiber are improved, thereby enhancing the overall mechanical properties and imaging visibility of the medical catheter. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the layered structure of the braided reinforcing fiber in the medical catheter of the present invention.

[0018] Figure 2 This is a magnified schematic diagram of the cross-section of the braided reinforcing fiber of the medical catheter of the present invention.

[0019] Figure 3 This is a process flow diagram of the preparation method of the present invention.

[0020] Figure 4 This is a schematic diagram of the plasma surface activation treatment of the present invention.

[0021] Figure 5 This is a schematic diagram of the melt extrusion coating process of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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. Example 1

[0023] Please see Figures 1-5 This invention relates to a medical catheter braided reinforcing fiber, comprising: Fiber core layer: The fiber core layer is composed of polymer filament bundles with a tensile strength of not less than 1.0 GPa. The polymer filament bundles are liquid crystal polymer filament bundles with a linear density of 50 dtex.

[0024] Interface modification layer: The interface modification layer is disposed on the surface of the fiber core layer and contains polar functional groups.

[0025] Thermoplastic adhesive coating layer: The thermoplastic adhesive coating layer covers the interface modification layer. The material of the thermoplastic adhesive coating layer is polyether block amide. The woven reinforcing fibers do not contain metal wires or ferromagnetic metal components. The outer diameter of the woven reinforcing fibers is 20 μm, and the thickness of the thermoplastic adhesive coating layer is 0.5 μm. The thermoplastic adhesive coating layer contains non-magnetic developing filler. The non-magnetic developing filler is barium sulfate with a particle size of 0.1 μm and a mass fraction of 5 wt%.

[0026] A method for preparing braided reinforcing fibers for medical catheters, comprising: S1. Provide a polymer filament bundle with a tensile strength of not less than 1.0 GPa. Use the polymer filament bundle as the fiber core layer, and clean and dry the fiber core layer to obtain the fiber core layer to be modified. The cleaning and drying include: cleaning with an organic solvent and rinsing with deionized water. The organic solvent is isopropanol. After cleaning, dry at 40°C for 20 min.

[0027] S2. Surface activation treatment is performed on the fiber core layer to be modified. The surface activation treatment is plasma treatment, which forms an interface modification layer containing polar functional groups on the surface of the fiber core layer to be modified. The plasma treatment uses oxygen plasma with a treatment power of 50W, a treatment time of 10s, and a treatment chamber pressure of 10Pa.

[0028] S3. Polyether block amide was selected as the matrix resin for the thermoplastic adhesive coating layer and melt-blended to obtain the coating material. When X-ray development was required, a non-magnetic developing filler was added to the coating material and mixed evenly. The non-magnetic developing filler was barium sulfate with a particle size of 0.1 μm and a mass fraction of 5 wt%. The melt-blending was performed using a twin-screw extruder. The melt-blending temperature of the matrix resin was 160℃, and the screw speed was 50 rpm. The non-magnetic developing filler was dried at 80℃ for 1 hour before being added.

[0029] S4. A melt extrusion coating process is used to coat the outer side of the interface modification layer with coating material. The thickness of the thermoplastic adhesive coating layer is controlled at 0.5 μm, and the outer diameter of the woven reinforcing fiber after forming is controlled at 20 μm. After cooling and forming, the shaped fiber is obtained. The extrusion temperature of the melt extrusion coating process is 160℃. During coating, a traction tension of 0.1N is applied to the fiber core layer. The thermoplastic adhesive coating layer continuously covers the fiber circumference, and the cooling temperature is 10℃.

[0030] S5. The formed fibers are heat-set and wound up to obtain medical catheter braided reinforcing fibers. The heat-setting treatment is carried out at 90℃ for 2 minutes. A constant tension of 0.2N is applied to the formed fibers during the heat-setting treatment, and the winding tension is 0.2N.

[0031] This embodiment corresponds to an ultra-fine diameter reinforced fiber structure. The fiber core has a low linear density, a thin coating layer, and a low barium sulfate content; the overall structure is characterized by reducing the outer diameter and improving flexibility. Basic X-ray visibility is achieved using a small amount of non-magnetic radiopaque filler under conditions free of metals and ferromagnetic components. After plasma surface activation to form polar functional groups, the interfacial bonding between the core layer and the polyether block amide coating layer is enhanced, meeting the requirements of minimally invasive, small-sized catheters for flexibility and space utilization.

[0032] Further analysis reveals that this embodiment, while controlling the outer diameter to a minimum, reduces bending stiffness through a lower coating thickness, minimizing the impact of braiding on the overall flexibility of the catheter and improving its adaptability when navigating complex vascular pathways. The lower filler content reduces the impact on the flowability of the resin continuous phase, ensuring a uniform and continuous coating layer and avoiding surface defects or stress concentrations caused by particle agglomeration. The overall structure emphasizes the coordination between diameter reduction, flexibility, and processing stability, making it suitable for minimally invasive interventional environments where instrument cross-sectional dimensions are highly sensitive. Example 2

[0033] Please see Figures 1-5 Based on Example 1, a medical catheter braided reinforcing fiber includes: Fiber core layer: The fiber core layer is composed of polymer filament bundles with a tensile strength of not less than 1.0 GPa. The polymer filament bundles are liquid crystal polymer filament bundles with a linear density of 175 dtex.

[0034] Interface modification layer: The interface modification layer is disposed on the surface of the fiber core layer and contains polar functional groups.

[0035] Thermoplastic adhesive coating layer: The thermoplastic adhesive coating layer covers the interface modification layer. The material of the thermoplastic adhesive coating layer is polyether block amide. The woven reinforcing fibers do not contain metal wires or ferromagnetic metal components. The outer diameter of the woven reinforcing fibers is 70 μm, and the thickness of the thermoplastic adhesive coating layer is 5.25 μm. The thermoplastic adhesive coating layer contains non-magnetic developing filler. The non-magnetic developing filler is barium sulfate, with a particle size of 1.05 μm and a mass fraction of 17.5 wt%.

[0036] A method for preparing braided reinforcing fibers for medical catheters, comprising: S1. Provide a polymer filament bundle with a tensile strength of not less than 1.0 GPa. Use the polymer filament bundle as the fiber core layer, and clean and dry the fiber core layer to obtain the fiber core layer to be modified. The cleaning and drying include: cleaning with an organic solvent and rinsing with deionized water. The organic solvent is isopropanol. After cleaning, dry at 60°C for 35 min.

[0037] S2. Surface activation treatment is performed on the fiber core layer to be modified. The surface activation treatment is plasma treatment, which forms an interface modification layer containing polar functional groups on the surface of the fiber core layer to be modified. The plasma treatment uses oxygen plasma with a treatment power of 175W, a treatment time of 95s, and a treatment chamber pressure of 105Pa.

[0038] S3. Polyether block amide was selected as the matrix resin for the thermoplastic adhesive coating layer and melt-blended to obtain the coating material. When X-ray development was required, a non-magnetic developing filler was added to the coating material and mixed evenly. The non-magnetic developing filler was barium sulfate with a particle size of 1.05 mm and a mass fraction of 17.5 wt%. The melt-blending was performed using a twin-screw extruder. The melt-blending temperature of the matrix resin was 200℃, and the screw speed was 175 rpm. The non-magnetic developing filler was dried at 100℃ for 3.5 h before being added.

[0039] S4. A melt extrusion coating process is used to coat the outer side of the interface modification layer with coating material. The thickness of the thermoplastic adhesive coating layer is controlled at 5.25 μm, and the outer diameter of the woven reinforcing fiber after forming is controlled at 70 μm. After cooling and forming, the shaped fiber is obtained. The extrusion temperature of the melt extrusion coating process is 200℃. During coating, a traction tension of 1.05 N is applied to the fiber core layer. The thermoplastic adhesive coating layer continuously covers the fiber circumference, and the cooling temperature is 20℃.

[0040] S5. The formed fibers are heat-set and wound up to obtain medical catheter braided reinforcing fibers. The heat-setting treatment is carried out at 107.5℃ for 6 minutes. A constant tension of 0.6N is applied to the formed fibers during the heat-setting treatment, and the winding tension is 0.5N.

[0041] The values ​​in this embodiment reflect a balance between strength, imaging performance, and structural stability. The fiber outer diameter, linear density, and coating thickness are all at moderate levels, while the increased barium sulfate filling ratio enhances imaging capability. A more stable interface modification layer is formed under high-energy plasma treatment conditions. Combined with sufficient melt mixing parameters, this facilitates filler dispersion and stable interfacial bonding, making it suitable for conventional interventional catheters requiring both support and visualization performance.

[0042] Within this value range, the core layer's load-bearing capacity and the coating layer's thickness are matched, ensuring that the reinforcing fibers provide sufficient radial support after weaving without significantly increasing the overall stiffness of the conduit. A moderate proportion of barium sulfate enhances X-ray contrast while maintaining the continuity and toughness of the resin matrix. The processing and structural parameters are coordinated to ensure uniform filler distribution and reliable interfacial adhesion, reducing the risk of interfacial peeling or pulverization during long-term bending use, reflecting a comprehensive performance optimization approach. Example 3

[0043] Please see Figures 1-5 Based on Examples 1 and 2, a medical catheter braided reinforcing fiber includes: Fiber core layer: The fiber core layer is composed of polymer filament bundles with a tensile strength of not less than 1.0 GPa. The polymer filament bundles are liquid crystal polymer filament bundles with a linear density of 300 dtex.

[0044] Interface modification layer: The interface modification layer is disposed on the surface of the fiber core layer and contains polar functional groups.

[0045] Thermoplastic adhesive coating layer: The thermoplastic adhesive coating layer covers the interface modification layer. The material of the thermoplastic adhesive coating layer is polyether block amide. The woven reinforcing fibers do not contain metal wires or ferromagnetic metal components. The outer diameter of the woven reinforcing fibers is 120 μm, and the thickness of the thermoplastic adhesive coating layer is 10 μm. The thermoplastic adhesive coating layer contains non-magnetic developing filler. The non-magnetic developing filler is barium sulfate with a particle size of 2 μm and a mass fraction of 30 wt%.

[0046] A method for preparing braided reinforcing fibers for medical catheters, comprising: S1. Provide a polymer filament bundle with a tensile strength of not less than 1.0 GPa. Use the polymer filament bundle as the fiber core layer, and clean and dry the fiber core layer to obtain the fiber core layer to be modified. The cleaning and drying include: cleaning with an organic solvent and rinsing with deionized water. The organic solvent is isopropanol. After cleaning, dry at 80°C for 50 min.

[0047] S2. Surface activation treatment is performed on the fiber core layer to be modified. The surface activation treatment is plasma treatment, which forms an interface modification layer containing polar functional groups on the surface of the fiber core layer to be modified. The plasma treatment uses oxygen plasma with a treatment power of 300W, a treatment time of 180s, and a treatment chamber pressure of 200Pa.

[0048] S3. Polyether block amide was selected as the matrix resin for the thermoplastic adhesive coating layer and melt-blended to obtain the coating material. When X-ray development was required, a non-magnetic developing filler was added to the coating material and mixed evenly. The non-magnetic developing filler was barium sulfate with a particle size of 2 μm and a mass fraction of 30 wt%. The melt blending was performed using a twin-screw extruder. The melt blending temperature of the matrix resin was 240℃, and the screw speed was 300 rpm. The non-magnetic developing filler was dried at 120℃ for 6 hours before being added.

[0049] S4. A melt extrusion coating process is used to coat the outer side of the interface modification layer with coating material. The thickness of the thermoplastic adhesive coating layer is controlled to be 10 μm, and the outer diameter of the woven reinforcing fiber after forming is controlled to be 120 μm. After cooling and forming, the shaped fiber is obtained. The extrusion temperature of the melt extrusion coating process is 240℃. During coating, a traction tension of 2N is applied to the fiber core layer. The thermoplastic adhesive coating layer continuously covers the fiber circumference, and the cooling temperature is 30℃.

[0050] S5. The formed fibers are heat-set and wound up to obtain medical catheter braided reinforcing fibers. The heat-setting treatment is carried out at 125℃ for 10 minutes. During the heat-setting treatment, a constant tension of 1.0N is applied to the formed fibers, and the winding tension is 0.8N.

[0051] This embodiment achieves a high load-bearing capacity and high imaging enhancement structure. The fiber core layer has a high linear density, the coating layer thickness is increased, and the barium sulfate filling ratio is high, resulting in significantly improved imaging contrast. To adapt to the high-filler system, the mixing temperature, rotation speed, and tension parameters are correspondingly increased to ensure coating continuity and structural stability. Under metal-free system conditions, it achieves high support strength and high visibility, making it suitable for catheter types requiring high structural rigidity and positioning clarity.

[0052] By increasing linear density and outer diameter, the load-bearing capacity of a single reinforcing fiber is improved, resulting in enhanced compressive and torsional support in the woven structure. A thicker coating layer provides sufficient dispersion space for the high proportion of developing filler, avoiding interface defects caused by increased filler content. High-temperature, high-shear mixing conditions enhance the uniformity of bonding between the filler and the matrix resin, ensuring the coating layer remains continuous and dense even under high-fill conditions. The overall structure is geared towards high strength, high stiffness, and high-resolution developing performance. Example 4

[0053] Please see Figures 1-5 Based on Examples 1, 2, and 3, the same batch of liquid crystal polymer filament bundles were selected as raw materials, and three process schemes were completed in batches on the same production line. The initial linear density of the liquid crystal polymer filament bundles was consistent, and the nominal tensile strength was not less than 1.0 GPa. The three groups were respectively designated as Sample A, Sample B, and Sample C.

[0054] 1. Pre-processing stage Sample A was dried using a low-temperature rapid drying method. After being cleaned with isopropanol, the fibers were placed in a 40°C hot air zone for 20 minutes. No additional tension compensation was required during the process, and the fibers maintained stable operation.

[0055] Sample B was transferred to a 60℃ drying zone after cleaning and left to dry for 35 minutes. As the temperature increased, the evaporation rate increased, and the tension of the winding section needed to be appropriately increased to ensure linear stability.

[0056] Sample C was continuously dried at 80℃ for 50 minutes. To avoid relaxation in the high-temperature zone, the equipment reduced the fiber feed speed and maintained constant tension control. The fiber residence time was the longest in the drying zone.

[0057] The three groups exhibited a progressive relationship from low to high heat load during the drying stage. Sample C had the highest treatment intensity, while sample A had the lowest. The heat treatment gradient resulted in different surface states, which formed the basis for the differences in subsequent plasma treatment.

[0058] 2. Plasma activation stage After sample A enters the plasma chamber, it undergoes a short-term, low-power processing. The equipment maintains a normal fiber feed speed, allowing the fiber to pass quickly through the chamber.

[0059] Sample B underwent increased power and extended treatment time. To ensure electric field stability, the chamber pressure needed to be adjusted and the operating speed appropriately reduced, allowing the fibers to remain in the plasma region for a longer period.

[0060] Sample C was processed with high power for an extended period. To ensure discharge stability, the chamber pressure was further adjusted, and the fiber feed speed was significantly reduced. The fiber remained in the activation zone for the longest time.

[0061] The fiber feeding speed is adjusted according to the processing time, so that the fiber stays in the cavity for the corresponding set time.

[0062] The intensity of plasma treatment increases progressively from sample A to sample C. Sample C has the strongest surface activation conditions, while sample A has the weakest. These different activation intensities form the basis for the differences in subsequent coating and binding capabilities.

[0063] 3. Mixing and Coating Stage Sample A used a low-filling system with a barium sulfate content of 5 wt% and a mixing temperature of 160℃. The melt had good fluidity, stable extrusion pressure, and a continuous coating process.

[0064] For sample B, the filler content was increased to 17.5 wt%, and the mixing temperature was raised to 200℃. With the increase in filler, the screw load increased, requiring an increase in traction tension to ensure stable coating thickness.

[0065] Sample C used a 30wt% high-filler system and a mixing temperature of 240℃. The high viscosity melt placed higher demands on the extrusion system, increasing the equipment load. To maintain uniform coating, the traction force and cooling rate were adjusted.

[0066] As the filler ratio and processing temperature increased from low to high, sample C formed the thickest coating layer, while sample A had the thinnest.

[0067] Differences in filler ratio and coating thickness provide the structural basis for differences in development performance.

[0068] 4. Finished Product Structure Stage After coating and heat setting, the three groups of samples formed reinforcing fibers of different specifications.

[0069] Sample A has an outer diameter of 20 μm and a coating thickness of 0.5 μm. The overall cross-sectional area of ​​the fiber is small, with a high core layer ratio and a low coating layer ratio, and the structure is mainly reinforced by small diameter fibers.

[0070] Sample B has an outer diameter of 70 μm and a coating thickness of 5.25 μm. Compared with sample A, the coating is significantly thicker, the cross-sectional area of ​​the reinforcing fibers is larger, and the content of the developing filler in the coating is increased due to the increased filler ratio.

[0071] Sample C has an outer diameter of 120 μm and a coating thickness of 10 μm. The coating forms a thick-walled structure with the highest filler content and the largest proportion of the developing layer in the cross-section.

[0072] From a geometric perspective: the outer diameter increased from 20μm to 120μm, the coating thickness increased from 0.5μm to 10μm, and the cross-sectional area increased in a stepwise manner.

[0073] As the coating thickness and filler ratio increase, the three groups of samples exhibit a gradient change from a thin-layer structure with a narrow diameter to a thick-walled, highly filled structure. Sample A is predominantly reinforced with a narrow diameter, Sample B has a medium-sized structure, and Sample C has a thick-walled, highly filled structure. This structural gradient provides a direct physical basis for the differences in subsequent mechanical and developmental properties.

[0074] 5. Unified performance testing Three groups of samples were tested under the same environmental conditions. The test environment was 23℃ and the relative humidity was 50%. Five samples were randomly selected from each group for testing, and the results were averaged.

[0075] Tensile property testing: An electronic universal testing machine was used with a clamping distance of 100 mm and a tensile speed of 50 mm / min. The breaking strength and elongation at break were recorded, and the cross-sectional area was calculated based on the measured outer diameter.

[0076] Interfacial peel strength test: The test was conducted using the 90° peel method, with a sample length of 100 mm and a peel speed of 20 mm / min. The average peel force during the stable peel phase was recorded.

[0077] X-ray imaging performance test: The test was conducted using medical X-ray imaging equipment with a working voltage of 60kV, a current of 5mA, and an exposure time of 0.2s. Using an aluminum stepped sheet as a reference, the gray value of the sample was converted into the equivalent aluminum thickness. The gray value was converted using a calibration curve established with the aluminum stepped sheet.

[0078] Table 1: Performance Test Results.

[0079]

[0080] Under the same test conditions, the fracture strength, interfacial bonding force, and equivalent aluminum thickness of samples A to C all increased with increasing process parameters.

[0081] The above steps lead to the following conclusions: Under the three sets of parameter combinations, samples with larger outer diameters have higher fracture strength, samples with higher plasma treatment intensity have greater interfacial bonding force, and samples with higher filler ratios have greater equivalent aluminum thickness.

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A medical catheter braided reinforcing fiber, characterized by, include: Fiber core layer: The fiber core layer is composed of polymer filament bundles, and the tensile strength of the polymer filament bundles is not less than 1.0 GPa; Interface modification layer: The interface modification layer is disposed on the surface of the fiber core layer, and the interface modification layer contains polar functional groups; Thermoplastic adhesive coating layer: The thermoplastic adhesive coating layer covers the interface modified layer. The material of the thermoplastic adhesive coating layer is selected from one or more of polyether block amide, thermoplastic polyurethane, and polyamide. The braided reinforcing fiber does not contain metal wires or ferromagnetic metal components. The outer diameter of the braided reinforcing fiber is 20μm-120μm. The thickness of the thermoplastic adhesive coating layer is 0.5μm-10μm.

2. The medical catheter braided reinforcing fiber according to claim 1, characterized in that: The polymer filament bundle is selected from one or more of ultra-high molecular weight polyethylene filament bundles, aramid filament bundles, and liquid crystal polymer filament bundles, and the linear density of the polymer filament bundle is 50 dtex-300 dtex.

3. The medical catheter braided reinforcing fiber according to claim 1, characterized in that: The thermoplastic adhesive coating layer contains a non-magnetic developing filler, which is barium sulfate or zirconium oxide, and the particle size of the non-magnetic developing filler is 0.1μm-2μm, and the mass fraction is 5wt%-30wt%.

4. A method for preparing braided reinforcing fibers for medical catheters, characterized in that, include: S1. Provide a polymer filament bundle, wherein the tensile strength of the polymer filament bundle is not less than 1.0 GPa, use the polymer filament bundle as a fiber core layer, and clean and dry the fiber core layer to obtain the fiber core layer to be modified. S2. The fiber core layer to be modified is subjected to surface activation treatment, wherein the surface activation treatment is plasma treatment or chemical oxidation treatment, so that an interface modification layer containing polar functional groups is formed on the surface of the fiber core layer to be modified. S3. Select one or more of polyether block amide, thermoplastic polyurethane, and polyamide as the base resin for the thermoplastic adhesive coating layer and melt-blend to obtain the coating material. When X-ray development is required, add a non-magnetic developing filler to the coating material and mix evenly. The non-magnetic developing filler is barium sulfate or zirconium oxide with a particle size of 0.1μm-2μm and a mass fraction of 5wt%-30wt%. S4. Using a melt extrusion coating process, the coating material is coated on the outside of the interface modification layer, the thickness of the thermoplastic adhesive coating layer is controlled to be 0.5μm-10μm, and the outer diameter of the woven reinforcing fiber after forming is controlled to be 20μm-120μm. After cooling and forming, the shaped fiber is obtained. S5. The shaped fiber is heat-set and wound up to obtain medical catheter braided reinforcing fiber.

5. The method for preparing a medical catheter braided reinforcing fiber according to claim 4, characterized in that: The cleaning and drying process includes: cleaning with an organic solvent and rinsing with deionized water, wherein the organic solvent is isopropanol; after cleaning, drying is carried out at 40℃-80℃ for 20min-50min, or drying is carried out under a vacuum degree not exceeding 20kPa for 20min-50min.

6. The method for preparing braided reinforcing fibers for medical catheters according to claim 4, characterized in that: The plasma treatment uses oxygen plasma or air plasma, with a processing power of 50W-300W, a processing time of 10s-180s, and a processing chamber pressure of 10Pa-200Pa.

7. The method for preparing a medical catheter braided reinforcing fiber according to claim 4, characterized in that: The chemical oxidation treatment uses hydrogen peroxide solution or potassium permanganate solution; the hydrogen peroxide solution has a mass fraction of 5wt%-30wt% and a treatment time of 3min-15min; the potassium permanganate solution has a mass fraction of 0.1wt%-5wt% and a treatment time of 1min-10min; after treatment, the solution is rinsed with deionized water and dried.

8. The method for preparing braided reinforcing fibers for medical catheters according to claim 4, characterized in that: The melt mixing is performed using a twin-screw extruder. The melt mixing temperature of the matrix resin is 160℃-240℃, and the screw speed is 50rpm-300rpm. The non-magnetic developing filler is dried at 80℃-120℃ for 1h-6h before being added.

9. The method for preparing a medical catheter braided reinforcing fiber according to claim 4, characterized in that: The extrusion temperature of the melt extrusion coating process is 160℃-240℃. During coating, a traction tension of 0.1N-2N is applied to the fiber core layer. The thermoplastic adhesive coating layer continuously covers the fiber circumferentially, and the cooling temperature is 10℃-30℃.

10. The method for preparing a medical catheter braided reinforcing fiber according to claim 4, characterized in that: The heat setting treatment is carried out at 90℃-125℃ for 2min-10min; during the heat setting treatment, a constant tension of 0.2N-1.0N is applied to the shaped fiber, and the winding tension is 0.2N-0.8N.

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