A three-layer co-extrusion balloon forming tube with different inner and outer layers and a preparation method thereof

Abstract

The application relates to the technical field of medical devices, and discloses an inner-outer layer difference enhanced three-layer co-extrusion balloon forming tube and a preparation method thereof. The preparation method comprises the following steps: inner layer premix preparation, selecting medical grade polyether block amide resin and a specific proportion of inner lubrication modifier to blend and granulate; middle layer premix preparation, selecting medical grade nylon 12 resin and surface modification enhanced short cut fiber to blend and granulate; outer layer premix preparation, selecting medical grade thermoplastic polyurethane and compound developing modifier and medical plasticizer to blend and granulate; and three-layer co-extrusion forming, the three kinds of granules are plasticized through independent extruders, are combined in a co-extrusion die head to form three-layer melt flow channels, and the finished product is obtained through sizing, cooling and traction cutting. The application improves the interlayer bonding strength of the balloon forming tube, improves the radial support performance of the pipe material, and improves the yield of the product and the safety of clinical use.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a three-layer co-extruded balloon tube with inner and outer layer difference reinforcement and its preparation method. Background Technology

[0002] Medical devices refer to instruments, equipment, appliances, in vitro diagnostic reagents and calibrators, materials, and other similar or related items that are used directly or indirectly on the human body, including the necessary computer software. Medical devices include medical equipment and medical consumables.

[0003] Currently, due to the significant differences in rheological properties of the melts in each layer during the three-layer co-extrusion process, it is impossible to monitor the temperature field and shear rate distribution in the melt convergence zone in real time when bonding the interlayer interfaces. When the molecular chain diffusion at the interface is insufficient, the interlayer bonding force will decrease significantly, and the structural integrity of the pipe cannot be guaranteed in the subsequent balloon blow molding process. At the same time, when adding reinforcing fibers, it is impossible to detect the dispersion uniformity and orientation state of the chopped fibers in the intermediate layer melt in real time, which will cause fiber agglomeration or local enrichment, resulting in stress concentration points in the pipe. Furthermore, when the fiber distribution is abnormal, the feeding parameters cannot be adjusted in real time.

[0004] Therefore, a three-layer co-extruded balloon tube with inner and outer layer difference reinforcement and its preparation method are proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement and its preparation method. This solves the problems mentioned in the background technology, such as the inability to monitor the temperature field and shear rate distribution of the melt confluence zone in real time when performing interlayer interface bonding, and the inability to detect the dispersion uniformity and orientation state of chopped fibers in the intermediate layer melt in real time when adding reinforcing fibers.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a three-layer co-extruded balloon tube with inner and outer layer differential reinforcement and its preparation method, comprising the following steps:

[0007] Step 1: Preparation of inner layer premix: Select medical-grade polyether block amide resin and internal lubricant modifier, mix them at a mass ratio of 100:(3-8), and melt-blend and granulate them through a twin-screw extruder to obtain inner layer granules;

[0008] Step 2: Preparation of intermediate layer premix: Select medical grade nylon 12 resin and reinforcing chopped fiber, mix them at a mass ratio of 100:(15-25), and melt-blend and granulate them through a twin-screw extruder to obtain intermediate layer granules;

[0009] Step 3: Preparation of outer layer premix: Select medical-grade thermoplastic polyurethane, a developing modifier, and a medical plasticizer, mix them at a mass ratio of 100:(10-18), and then melt-blend and granulate them using a twin-screw extruder to obtain outer layer granules;

[0010] Step 4: Three-layer co-extrusion molding. The inner layer granules, middle layer granules and outer layer granules are fed into three single-screw extruders respectively. The three layers of melt are combined through the co-extrusion die. After cooling and shaping by the sizing sleeve and traction cutting, a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement is obtained.

[0011] Preferably, in step one, the internal lubricant modifier is a compound of polydimethylsiloxane and calcium stearate in a mass ratio of 2:1; the processing temperature of the twin-screw extruder is 220℃-240℃, the screw speed is 300r / min-400r / min, and the vacuum degree is -0.08MPa to -0.06MPa.

[0012] Preferably, the method for preparing the inner layer granules further includes:

[0013] Before melt blending, the polyether block amide resin is dried in an 80℃ vacuum oven for 4-6 hours to reduce its moisture content to less than 0.05%. Before adding the internal lubricant modifier, it is stirred in a high-speed mixer at 1000-1200r / min for 5-8 minutes. After being mixed evenly, it is added to the twin-screw extruder through the side feed port.

[0014] Preferably, in step two, the reinforcing chopped fiber is a medical-grade polyarylate fiber with a surface modified by silane coupling agent KH-570, the fiber length is 50μm-100μm and the diameter is 8μm-12μm; the processing temperature of the twin-screw extruder is 230℃-250℃, the screw speed is 280r / min-380r / min, and the vacuum degree is -0.09MPa to -0.07MPa.

[0015] Preferably, the modification method of the silane coupling agent KH-570 is as follows:

[0016] Medical-grade polyarylate fibers are placed in a 1%-3% KH-570 ethanol solution and ultrasonically treated at 40℃-50℃ for 20-30 minutes. After removal, they are dried in an oven at 100℃-120℃ for 2-3 hours. The intermediate layer granules also contain 0.5-1.5 parts of antioxidant 1010 and 0.3-0.8 parts of ultraviolet absorber UV-329.

[0017] Preferably, in step three, the developing modifier is a compound of barium sulfate and iohexol in a mass ratio of 3:1, the barium sulfate has a particle size of 1μm-3μm, the iohexol has a particle size of 0.5μm-1μm, the twin-screw extruder has a processing temperature of 200℃-220℃, a screw speed of 320r / min-420r / min, and a vacuum degree of -0.08MPa to -0.06MPa.

[0018] Preferably, the method for preparing the outer granules further includes:

[0019] During melt blending, the preferred medical plasticizer is diisononyl cyclohexane-1,2-dicarboxylic acid, and 1-3 parts of lubricant polyethylene wax; the imaging modifier is accurately metered using a loss-in-weight feeder, with the addition error controlled within ±0.5%.

[0020] Preferably, in step four, the temperature parameters of the three single-screw extruders are as follows:

[0021] The inner extruder barrel temperature is 210℃-230℃, the die head temperature is 220℃-225℃, the middle extruder barrel temperature is 220℃-240℃, the die head temperature is 230℃-235℃, and the outer extruder barrel temperature is 190℃-210℃, the die head temperature is 200℃-205℃.

[0022] Preferably, the compression ratio of the co-extrusion die is 2.5-3.5, the inner diameter of the sizing sleeve is 2mm-10mm, the cooling water temperature is 15℃-25℃, the traction speed is 1.5m / min-3.5m / min, and in the case of three-layer co-extrusion, the inner layer wall thickness accounts for 20%-30%, the middle layer wall thickness accounts for 50%-60%, and the outer layer wall thickness accounts for 15%-25%.

[0023] Preferably, the structure comprises an inner layer, a middle layer, and an outer layer arranged sequentially from the inside out. The inner layer is composed of polyether block amide resin and an internal lubricant modifier in a mass ratio of 100:(3-8). The middle layer is composed of nylon 12 resin and reinforcing chopped fibers in a mass ratio of 100:(15-25). The outer layer is composed of thermoplastic polyurethane, a imaging modifier, and a medical plasticizer in a mass ratio of 100:(10-18). The inner layer has a wall thickness of 20%-30%, the middle layer has a wall thickness of 50%-60%, and the outer layer has a wall thickness of 15%-25%. The inner layer, middle layer, and outer layer are formed into a metallurgical bond structure without interfaces through melt co-extrusion.

[0024] Compared with the prior art, the present invention provides a three-layer co-extruded balloon tube with inner and outer layer differential reinforcement and its preparation method, which has the following beneficial effects:

[0025] 1. In this invention, during the three-layer co-extrusion molding process, by selecting a specific ratio of internal lubricating modifier and polyether block amide resin, and by using reinforcing chopped fibers and nylon 12 resin composite, the high temperature and high pressure environment of the three-layer melt in the co-extrusion die promotes the mutual diffusion and entanglement of molecular chains at the interface. This enables the real-time construction of a metallurgical bond structure between the inner, middle, and outer layers, solving the risk of interlayer delamination caused by differences in material rheological properties, ensuring the structural integrity of the tube during subsequent processing and use, and improving the interlayer bonding strength of the balloon-shaped tube.

[0026] 2. In this invention, during the preparation of the intermediate layer premix, the surface of the reinforcing chopped fibers is modified with silane coupling agent KH-570, which can optimize the dispersion state and orientation distribution of the fibers in the melt in real time, solve the stress concentration points caused by fiber agglomeration, and when abnormal fiber distribution occurs, it can be corrected in real time by adjusting the screw combination and shear rate, ensuring the uniformity of the intermediate layer reinforcement effect and improving the radial support performance of the pipe.

[0027] 3. In this invention, during the three-layer co-extrusion molding process, by independently controlling the temperature parameters of the three single-screw extruders and the cooling conditions of the sizing sleeve, the melt flow behavior can be dynamically adjusted according to the melting characteristics of different layer materials, achieving an accurate proportional distribution of the inner, middle, and outer layer wall thicknesses. This avoids eccentricity or layer thickness deviations in the tube. Furthermore, when the wall thickness ratio deviates from the design value, it can be corrected in real time by adjusting the traction speed and extrusion rate, ensuring uniform mechanical transmission during balloon expansion and improving product yield and safety for clinical use. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1: A three-layer co-extruded balloon tube with inner and outer layer differential reinforcement and its preparation method, comprising the following steps:

[0030] Step 1: Preparation of inner layer premix: Select medical-grade polyether block amide resin and internal lubricant modifier, mix them at a mass ratio of 100:3, and melt-blend and granulate them through a twin-screw extruder to obtain inner layer granules;

[0031] Step 2: Preparation of intermediate layer premix: Medical grade nylon 12 resin and reinforcing chopped fibers are selected and mixed at a mass ratio of 100:15. The mixture is then melt-blended and granulated using a twin-screw extruder to obtain intermediate layer granules.

[0032] Step 3: Preparation of outer layer premix: Select medical-grade thermoplastic polyurethane, a developing modifier, and a medical plasticizer, mix them at a mass ratio of 100:10, and then melt-blend and granulate them using a twin-screw extruder to obtain the outer layer granules;

[0033] Step 4: Three-layer co-extrusion molding. The inner layer granules, middle layer granules and outer layer granules are fed into three single-screw extruders respectively. The three layers of melt are combined through the co-extrusion die. After cooling and shaping by the sizing sleeve and traction cutting, a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement is obtained.

[0034] In step one, the internal lubricant modifier is a compound of polydimethylsiloxane and calcium stearate in a mass ratio of 2:1; the processing temperature of the twin-screw extruder is 220℃, the screw speed is 300r / min, and the vacuum degree is -0.08MPa.

[0035] The preparation methods for inner layer granules also include:

[0036] Before melt blending, the polyether block amide resin was dried in an 80°C vacuum oven for 4 hours to reduce its moisture content to less than 0.05%. The internal lubricant modifier was stirred at 1000 r / min for 5 minutes in a high-speed mixer before being added. After being mixed evenly, it was added to the twin-screw extruder through the side feed port.

[0037] In step two, the reinforcing chopped fiber is a medical-grade polyarylate fiber with a surface modified by silane coupling agent KH-570, with a fiber length of 50μm and a diameter of 8μm; the processing temperature of the twin-screw extruder is 230℃, the screw speed is 280r / min, and the vacuum degree is -0.09MPa.

[0038] The modification method for silane coupling agent KH-570 is as follows:

[0039] Medical-grade polyarylate fiber was placed in a 1% KH-570 ethanol solution and ultrasonically treated at 40°C for 20 minutes. After removal, it was dried in an oven at 100°C for 2 hours. The intermediate layer granules also contained 0.5 parts of antioxidant 1010 and 0.3 parts of ultraviolet absorber UV-329.

[0040] In step three, the developing modifier is a mixture of barium sulfate and iohexol in a mass ratio of 3:1. The barium sulfate has a particle size of 1 μm, and the iohexol has a particle size of 0.5 μm. The processing temperature of the twin-screw extruder is 200℃, the screw speed is 320 r / min, and the vacuum degree is -0.08 MPa.

[0041] The preparation methods for the outer granules also include:

[0042] During melt blending, the preferred medical plasticizer is diisononyl cyclohexane-1,2-dicarboxylic acid, and 1 part of lubricant polyethylene wax; the imaging modifier is accurately metered using a loss-in-weight feeder, with the addition error controlled within ±0.5%.

[0043] In step four, the temperature parameters of the three single-screw extruders are as follows:

[0044] The inner extruder barrel temperature is 210℃, the die head temperature is 220℃, the middle extruder barrel temperature is 220℃, the die head temperature is 230℃, and the outer extruder barrel temperature is 190℃, the die head temperature is 200℃.

[0045] The compression ratio of the co-extrusion die is 2.5, the inner diameter of the sizing sleeve is 2mm, the cooling water temperature is 15℃, the traction speed is 1.5m / min, and in the three-layer co-extrusion, the inner layer wall thickness accounts for 20%, the middle layer wall thickness accounts for 50%, and the outer layer wall thickness accounts for 15%.

[0046] It comprises an inner layer, a middle layer, and an outer layer arranged sequentially from the inside out. The inner layer is composed of polyether block amide resin and internal lubricant modifier in a mass ratio of 100:3. The middle layer is composed of nylon 12 resin and reinforcing chopped fibers in a mass ratio of 100:15. The outer layer is composed of thermoplastic polyurethane, a imaging modifier, and a medical plasticizer in a mass ratio of 100:10. The inner layer accounts for 20% of the wall thickness, the middle layer accounts for 50%, and the outer layer accounts for 15%. The inner, middle, and outer layers are melt-co-extruded to form an interface-free metallurgical bond structure.

[0047] Example 2: A three-layer co-extruded balloon tube with inner and outer layer differential reinforcement and its preparation method, comprising the following steps:

[0048] Step 1: Preparation of inner layer premix: Select medical-grade polyether block amide resin and internal lubricant modifier, mix them at a mass ratio of 100:5.5, and melt-blend and granulate them through a twin-screw extruder to obtain inner layer granules;

[0049] Step 2: Preparation of intermediate layer premix: Medical grade nylon 12 resin and reinforcing chopped fibers are selected and mixed at a mass ratio of 100:20. The mixture is then melt-blended and granulated using a twin-screw extruder to obtain intermediate layer granules.

[0050] Step 3: Preparation of outer layer premix: Select medical-grade thermoplastic polyurethane, a developing modifier, and a medical plasticizer, mix them at a mass ratio of 100:14, and then melt-blend and granulate them using a twin-screw extruder to obtain the outer layer granules;

[0051] Step 4: Three-layer co-extrusion molding. The inner layer granules, middle layer granules and outer layer granules are fed into three single-screw extruders respectively. The three layers of melt are combined through the co-extrusion die. After cooling and shaping by the sizing sleeve and traction cutting, a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement is obtained.

[0052] In step one, the internal lubricant modifier is a compound of polydimethylsiloxane and calcium stearate in a mass ratio of 2:1; the processing temperature of the twin-screw extruder is 230℃, the screw speed is 350r / min, and the vacuum degree is -0.07MPa.

[0053] The preparation methods for inner layer granules also include:

[0054] Before melt blending, the polyether block amide resin was dried in a vacuum oven at 80°C for 5 hours to reduce its moisture content to less than 0.05%. The internal lubricant modifier was stirred at 1100 r / min for 6.5 min in a high-speed mixer before being added. After being mixed evenly, it was added to the twin-screw extruder through the side feed port.

[0055] In step two, the reinforcing chopped fiber is a medical-grade polyarylate fiber with a surface modified by silane coupling agent KH-570, with a fiber length of 75μm and a diameter of 10μm; the processing temperature of the twin-screw extruder is 240℃, the screw speed is 330r / min, and the vacuum degree is -0.08MPa.

[0056] The modification method for silane coupling agent KH-570 is as follows:

[0057] Medical-grade polyarylate fiber was placed in a 2% KH-570 ethanol solution and ultrasonically treated at 45°C for 25 minutes. After removal, it was dried in an oven at 110°C for 2.5 hours. The intermediate layer granules also contained 1.0 part of antioxidant 1010 and 0.55 parts of ultraviolet absorber UV-329.

[0058] In step three, the developing modifier is a mixture of barium sulfate and iohexol in a mass ratio of 3:1. The barium sulfate has a particle size of 2 μm, the iohexol has a particle size of 0.75 μm, the twin-screw extruder has a processing temperature of 210℃, a screw speed of 370 r / min, and a vacuum degree of -0.07 MPa.

[0059] The preparation methods for the outer granules also include:

[0060] During melt blending, the preferred medical plasticizer is diisononyl cyclohexane-1,2-dicarboxylic acid, and 2 parts of lubricant polyethylene wax; the imaging modifier is accurately metered using a loss-in-weight feeder, with the addition error controlled within ±0.5%.

[0061] In step four, the temperature parameters of the three single-screw extruders are as follows:

[0062] The inner extruder barrel temperature is 220℃, the die head temperature is 222.5℃, the middle extruder barrel temperature is 230℃, the die head temperature is 232.5℃, and the outer extruder barrel temperature is 200℃, the die head temperature is 202.5℃.

[0063] The compression ratio of the co-extrusion die is 3.0, the inner diameter of the sizing sleeve is 6mm, the cooling water temperature is 20℃, the traction speed is 2.0m / min, and in the three-layer co-extrusion, the inner layer wall thickness accounts for 25%, the middle layer wall thickness accounts for 55%, and the outer layer wall thickness accounts for 20%.

[0064] It comprises an inner layer, a middle layer, and an outer layer arranged sequentially from the inside out. The inner layer is composed of polyether block amide resin and internal lubricant modifier in a mass ratio of 100:5.5. The middle layer is composed of nylon 12 resin and reinforcing chopped fibers in a mass ratio of 100:20. The outer layer is composed of thermoplastic polyurethane, a imaging modifier, and a medical plasticizer in a mass ratio of 100:14. The inner layer accounts for 25% of the wall thickness, the middle layer accounts for 55%, and the outer layer accounts for 20%. The inner, middle, and outer layers are melt-co-extruded to form an interface-free metallurgical bond structure.

[0065] Example 3: A three-layer co-extruded balloon tube with inner and outer layer differential reinforcement and its preparation method, comprising the following steps:

[0066] Step 1: Preparation of inner layer premix: Select medical-grade polyether block amide resin and internal lubricant modifier, mix them at a mass ratio of 100:8, and melt-blend and granulate them through a twin-screw extruder to obtain inner layer granules;

[0067] Step 2: Preparation of intermediate layer premix: Medical grade nylon 12 resin and reinforcing chopped fibers are selected and mixed at a mass ratio of 100:25. The mixture is then melt-blended and granulated using a twin-screw extruder to obtain intermediate layer granules.

[0068] Step 3: Preparation of outer layer premix: Select medical-grade thermoplastic polyurethane, a developing modifier, and a medical plasticizer, mix them at a mass ratio of 100:18, and then melt-blend and granulate them using a twin-screw extruder to obtain the outer layer granules;

[0069] Step 4: Three-layer co-extrusion molding. The inner layer granules, middle layer granules and outer layer granules are fed into three single-screw extruders respectively. The three layers of melt are combined through the co-extrusion die. After cooling and shaping by the sizing sleeve and traction cutting, a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement is obtained.

[0070] In step one, the internal lubricant modifier is a compound of polydimethylsiloxane and calcium stearate in a mass ratio of 2:1; the processing temperature of the twin-screw extruder is 240℃, the screw speed is 400r / min, and the vacuum degree is -0.06MPa.

[0071] The preparation methods for inner layer granules also include:

[0072] Before melt blending, the polyether block amide resin was dried in an 80°C vacuum oven for 6 hours to reduce its moisture content to less than 0.05%. The internal lubricant modifier was stirred at 1200 r / min for 8 minutes in a high-speed mixer before being added. After being mixed evenly, it was added to the twin-screw extruder through the side feed port.

[0073] In step two, the reinforcing chopped fiber is a medical-grade polyarylate fiber with a surface modified by silane coupling agent KH-570. The fiber length is 100μm and the diameter is 12μm. The processing temperature of the twin-screw extruder is 250℃, the screw speed is 380r / min, and the vacuum degree is -0.07MPa.

[0074] The modification method for silane coupling agent KH-570 is as follows:

[0075] Medical-grade polyarylate fiber was placed in a 3% KH-570 ethanol solution and ultrasonically treated at 50°C for 30 minutes. After removal, it was dried in an oven at 120°C for 3 hours. The intermediate layer granules also contained 1.5 parts of antioxidant 1010 and 0.8 parts of ultraviolet absorber UV-329.

[0076] In step three, the developing modifier is a mixture of barium sulfate and iohexol in a mass ratio of 3:1. The barium sulfate has a particle size of 3μm, and the iohexol has a particle size of 1μm. The processing temperature of the twin-screw extruder is 220℃, the screw speed is 420r / min, and the vacuum degree is -0.06MPa.

[0077] The preparation methods for the outer granules also include:

[0078] During melt blending, the preferred medical plasticizer is diisononyl cyclohexane-1,2-dicarboxylic acid, and 3 parts of lubricant polyethylene wax; the imaging modifier is accurately metered using a loss-in-weight feeder, with the addition error controlled within ±0.5%.

[0079] In step four, the temperature parameters of the three single-screw extruders are as follows:

[0080] The inner extruder barrel temperature is 230℃, the die head temperature is 225℃, the middle extruder barrel temperature is 240℃, the die head temperature is 235℃, and the outer extruder barrel temperature is 210℃ and the die head temperature is 205℃.

[0081] The compression ratio of the co-extrusion die is 3.5, the inner diameter of the sizing sleeve is 10mm, the cooling water temperature is 25℃, the traction speed is 3.5m / min, and in the three-layer co-extrusion, the inner layer wall thickness accounts for 30%, the middle layer wall thickness accounts for 60%, and the outer layer wall thickness accounts for 25%.

[0082] It comprises an inner layer, a middle layer, and an outer layer arranged sequentially from the inside out. The inner layer is composed of polyether block amide resin and internal lubricant modifier in a mass ratio of 100:8. The middle layer is composed of nylon 12 resin and reinforcing chopped fibers in a mass ratio of 100:25. The outer layer is composed of thermoplastic polyurethane, a imaging modifier, and a medical plasticizer in a mass ratio of 100:18. The inner layer accounts for 30% of the wall thickness, the middle layer accounts for 60%, and the outer layer accounts for 25%. The inner, middle, and outer layers are melt-co-extruded to form an interface-free metallurgical bond structure.

[0083] Comparative Example 1: The difference between this comparative example and Example 1 is that no internal lubricating modifier was added when preparing the inner layer premix in this comparative example, and only medical-grade polyether block amide resin was used for granulation.

[0084] Comparative Example 2 differs from Example 2 in that: in preparing the intermediate layer premix, the reinforcing chopped fibers were not surface-modified with silane coupling agent KH-570, and medical-grade polyarylate fibers were directly blended with nylon 12 resin.

[0085] Comparative Example 3 differs from Example 3 in that: no developing modifier was added in the preparation of the outer layer premix in this comparative example, and only medical-grade thermoplastic polyurethane was used for separate granulation.

[0086] Comparative Example 4 differs from Example 3 in that the temperature parameters of the three single-screw extruders in this comparative example are out of control during the three-layer co-extrusion molding, and the cooling and shaping are not carried out by the sizing sleeve, but only by natural cooling.

[0087] Performance tests were conducted on the three-layer co-extruded balloon tubes with inner and outer layer difference reinforcement in Examples 1-3 and Comparative Examples 1-4, and their preparation methods. The test items and methods are as follows:

[0088] Interlayer bonding strength test: Through interface peeling test, observe the ease of separation between inner layer, middle layer and outer layer, and determine whether there is a metallurgical bonding structure without interface;

[0089] Radial support force test: Simulating balloon inflation, axial tension and radial constraint are applied to observe the tube's ability to resist collapse and deformation;

[0090] Wall thickness uniformity test: Samples are taken at multiple points along the axial and circumferential directions of the pipe to compare the deviation between the actual wall thickness and the design value;

[0091] Interface microstructure observation: By analyzing the cross-sectional micromorphology, we can detect whether there are obvious dividing lines or gaps at the interfaces of each layer.

[0092] The test data of the three-layer co-extruded balloon tube with inner and outer layer difference reinforcement and its preparation method in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below:

[0093] Example 1 12.8 38.5 1.2 No interface Example 2 13.5 42.1 0.9 No interface Example 3 14.2 45.3 1.1 No interface Comparative Example 1 4.2 22.7 1.5 0.8 Comparative Example 2 7.9 15.3 1.8 1.2 Comparative Example 3 8.1 26.4 1.6 1.0 Comparative Example 4 2.3 10.8 8.7 0.3

[0094] By comparing and analyzing the data in the table, it can be seen that the three-layer co-extruded balloon-shaped tube and its preparation method with inner and outer layer difference reinforcement in Examples 1-3 have superior performance compared with the three-layer co-extruded balloon-shaped tube and its preparation method with inner and outer layer difference reinforcement in Comparative Examples 1-4. This indicates that during the three-layer co-extrusion molding, by selecting a specific ratio of internal lubricating modifier and polyether block amide resin, and by using medical-grade polyarylate fiber and nylon 12 resin composite, the high temperature and high pressure environment of the three-layer melt in the co-extrusion die promotes the mutual diffusion and entanglement of molecular chains at the interface, which can build a metallurgical bond structure of inner, middle and outer layers in real time. This solves the risk of interlayer delamination caused by differences in material rheological properties, ensures the structural integrity of the tube during subsequent processing and use, and improves the interlayer bonding strength of the balloon-shaped tube. When preparing the middle layer premix, by... Medical-grade polyarylate fibers are surface-modified with silane coupling agent KH-570, which can optimize the dispersion and orientation distribution of fibers in the melt in real time, solve stress concentration points caused by fiber agglomeration, and correct abnormal fiber distribution in real time by adjusting the screw combination and shear rate, ensuring the uniformity of the intermediate layer reinforcement effect and improving the radial support performance of the tube. During three-layer co-extrusion molding, by independently controlling the temperature parameters of the three single-screw extruders and the cooling conditions of the sizing sleeve, the melt flow behavior can be dynamically adjusted according to the melting characteristics of different layer materials, achieving accurate proportional distribution of the inner, intermediate, and outer layer wall thicknesses, avoiding eccentricity or layer thickness deviations in the tube. When the wall thickness ratio deviates from the design value, it can be corrected in real time by adjusting the traction speed and extrusion rate, ensuring the uniformity of mechanical transmission during balloon expansion, improving product yield and clinical safety.

[0095] By comparing and analyzing the relevant data in the table, it can be seen that the three-layer co-extruded balloon tube with inner and outer layer difference reinforcement and its preparation method have better comprehensive performance.

[0096] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0097] 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 method for preparing a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement, characterized in that, Includes the following steps: Step 1: Preparation of inner layer premix: Select medical-grade polyether block amide resin and internal lubricant modifier, mix them at a mass ratio of 100:(3-8), and melt-blend and granulate them through a twin-screw extruder to obtain inner layer granules; Step 2: Preparation of intermediate layer premix: Select medical grade nylon 12 resin and reinforcing chopped fiber, mix them at a mass ratio of 100:(15-25), and melt-blend and granulate them through a twin-screw extruder to obtain intermediate layer granules; Step 3: Preparation of outer layer premix: Select medical-grade thermoplastic polyurethane, a developing modifier, and a medical plasticizer, mix them at a mass ratio of 100:(10-18), and then melt-blend and granulate them using a twin-screw extruder to obtain the outer layer granules; Step 4: Three-layer co-extrusion molding. The inner layer granules, middle layer granules and outer layer granules are fed into three single-screw extruders respectively. The three layers of melt are combined through the co-extrusion die. After cooling and shaping by the sizing sleeve and traction cutting, a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement is obtained.

2. The method for preparing a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement according to claim 1, characterized in that, In step one, the internal lubricant modifier is a compound of polydimethylsiloxane and calcium stearate in a mass ratio of 2:1; the processing temperature of the twin-screw extruder is 220℃-240℃, the screw speed is 300r / min-400r / min, and the vacuum degree is -0.08MPa to -0.06MPa.

3. The method for preparing a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement according to claim 1, characterized in that, The method for preparing the inner layer granules further includes: Before melt blending, the polyether block amide resin is dried in an 80℃ vacuum oven for 4-6 hours to reduce its moisture content to less than 0.05%. Before adding the internal lubricant modifier, it is stirred in a high-speed mixer at 1000-1200r / min for 5-8 minutes. After being mixed evenly, it is added to the twin-screw extruder through the side feed port.

4. The method for preparing a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement according to claim 1, characterized in that, In step two, the reinforcing chopped fibers are medical-grade polyarylate fibers with a surface modified by silane coupling agent KH-570, with a fiber length of 50μm-100μm and a diameter of 8μm-12μm; the processing temperature of the twin-screw extruder is 230℃-250℃, the screw speed is 280r / min-380r / min, and the vacuum degree is -0.09MPa to -0.07MPa.

5. The method for preparing a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement according to claim 4, characterized in that, The modification method of the silane coupling agent KH-570 is as follows: Medical-grade polyarylate fibers are placed in a 1%-3% KH-570 ethanol solution and ultrasonically treated at 40℃-50℃ for 20-30 minutes. After removal, they are dried in an oven at 100℃-120℃ for 2-3 hours. The intermediate layer granules also contain 0.5-1.5 parts of antioxidant 1010 and 0.3-0.8 parts of ultraviolet absorber UV-329.

6. The method for preparing a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement according to claim 1, characterized in that, In step three, the developing modifier is composed of barium sulfate and iohexol in a mass ratio of 3:

1. The barium sulfate has a particle size of 1μm-3μm, and the iohexol has a particle size of 0.5μm-1μm. The processing temperature of the twin-screw extruder is 200℃-220℃, the screw speed is 320r / min-420r / min, and the vacuum degree is -0.08MPa to -0.06MPa.

7. The method for preparing a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement according to claim 1, characterized in that, The method for preparing the outer layer granules further includes: During melt blending, the preferred medical plasticizer is diisononyl cyclohexane-1,2-dicarboxylic acid, and 1-3 parts of lubricant polyethylene wax; the imaging modifier is accurately metered using a loss-in-weight feeder, with the addition error controlled within ±0.5%.

8. The method for preparing a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement according to claim 1, characterized in that, In step four, the temperature parameters of the three single-screw extruders are as follows: The inner extruder barrel temperature is 210℃-230℃, the die head temperature is 220℃-225℃, the middle extruder barrel temperature is 220℃-240℃, the die head temperature is 230℃-235℃, and the outer extruder barrel temperature is 190℃-210℃, the die head temperature is 200℃-205℃.

9. The method for preparing a three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement according to claim 1, characterized in that, The compression ratio of the co-extrusion die is 2.5-3.5, the inner diameter of the sizing sleeve is 2mm-10mm, the cooling water temperature is 15℃-25℃, the traction speed is 1.5m / min-3.5m / min, and in the case of three-layer co-extrusion, the inner layer wall thickness accounts for 20%-30%, the middle layer wall thickness accounts for 50%-60%, and the outer layer wall thickness accounts for 15%-25%.

10. A three-layer co-extruded balloon-shaped tube with inner and outer layer differential reinforcement, characterized in that, The method for preparing a three-layer co-extruded balloon tube with inner and outer layer difference reinforcement as described in any one of claims 1-9 includes an inner layer, an intermediate layer, and an outer layer arranged sequentially from the inside to the outside. The inner layer is composed of polyether block amide resin and an internal lubricating modifier in a mass ratio of 100:(3-8). The intermediate layer is composed of nylon 12 resin and reinforcing chopped fibers in a mass ratio of 100:(15-25). The outer layer is composed of thermoplastic polyurethane, a imaging modifier, and a medical plasticizer in a mass ratio of 100:(10-18). The wall thickness of the inner layer accounts for 20%-30%, the wall thickness of the intermediate layer accounts for 50%-60%, and the wall thickness of the outer layer accounts for 15%-25%. The inner layer, intermediate layer, and outer layer are formed into an interface-free metallurgical bond structure through melt co-extrusion.