Medical heat shrink tube and preparation process

Abstract

The invention belongs to the technical field of medical treatment, and particularly relates to a medical heat shrink tubing and a preparation process thereof, the medical heat shrink tubing comprises 40%-60% of special modified polyethylene, 20%-35% of thermoplastic polyurethane elastomer, 5%-15% of a nanoscale inorganic particle reinforcing agent, 0.5%-2% of an antioxidant and 3%-10% of a plasticizer, the nano-scale inorganic particle reinforcing agent is nano titanium dioxide or nano calcium carbonate, the antioxidant is a hindered phenol antioxidant, and the plasticizer is an environment-friendly polyester plasticizer, so that the problems that an existing medical heat shrinkable tube is poor in flexibility, insufficient in heat stability, poor in biocompatibility, complex in preparation process and high in cost are solved.

Description

Technical Field

[0001] This invention belongs to the field of medical technology, and in particular relates to a medical heat shrink tubing and its manufacturing process. Background Technology

[0002] In the medical field, heat shrink tubing is widely used in the assembly, protection, and connection of medical devices. For example, in the manufacturing process of catheters, heat shrink tubing is used to tightly connect different components and provide a seal; in some implantable medical devices, heat shrink tubing can provide insulation and protection for internal electronic components. However, existing medical heat shrink tubing has many shortcomings.

[0003] On the one hand, some heat shrink tubing lacks flexibility, making it difficult to achieve a good fit in scenarios where bending or fitting complex-shaped medical device parts is required, thus affecting the normal use and ease of operation of the device.

[0004] On the other hand, heat shrink tubing lacks thermal stability. When subjected to high-temperature sterilization or heating during use, it may experience excessive shrinkage, deformation, or even performance degradation, failing to meet the stringent requirements of medical environments. Furthermore, some heat shrink tubing may present biocompatibility issues when in contact with human tissue or other components of medical devices, potentially causing adverse reactions.

[0005] The existing technology for applying anti-corrosion coating to heat shrink tubing is not ideal, and residual particles are easily found on the surface of the heat shrink tubing, resulting in an uneven surface.

[0006] In addition, the existing heat shrink tubing manufacturing process is complex and costly, which is not conducive to large-scale production and application. Summary of the Invention

[0007] The purpose of this invention is to address the aforementioned technical problems by providing a medical heat shrink tubing and its manufacturing process, thereby solving the problems of poor flexibility, insufficient thermal stability, poor biocompatibility, and complex and costly manufacturing processes of existing medical heat shrink tubing.

[0008] In view of this, the present invention provides a medical heat shrink tubing, comprising the following components by weight percentage: 40%-60% specially modified polyethylene, 20%-35% thermoplastic polyurethane elastomer, 5%-15% nano-level inorganic particle reinforcing agent, 0.5%-2% antioxidant, and 3%-10% plasticizer; wherein the specially modified polyethylene is graft-modified polyethylene with introduced corrosion-resistant groups, the nano-level inorganic particle reinforcing agent is nano-titanium dioxide or nano-calcium carbonate, the antioxidant is a hindered phenolic antioxidant, and the plasticizer is an environmentally friendly polyester plasticizer.

[0009] Preferably, the specially modified polyethylene is modified by grafting carboxyl groups (-COOH) or hydroxyl groups (-OH) onto the polyethylene molecular chain, with a grafting rate of 5%-8%.

[0010] Preferably, the Shore hardness of the thermoplastic polyurethane elastomer is 80A-85A.

[0011] Preferably, the average particle size of the nanoscale inorganic particle reinforcing agent is 50nm-80nm.

[0012] Preferably, the antioxidant is antioxidant 1010 or antioxidant 168.

[0013] A process for manufacturing medical heat shrink tubing includes the following steps: S1. Raw material pretreatment: The specially modified polyethylene and thermoplastic polyurethane elastomer are dried at 80-100℃ for 4-6 hours; the nano-sized inorganic particle reinforcing agent is surface activated in a ball mill. S2. Mixing and stirring: According to the mass percentage described in claim 1, the specially modified polyethylene, thermoplastic polyurethane elastomer, nano-sized inorganic particle reinforcing agent, antioxidant, and plasticizer treated in step S1 are added to a high-speed mixer and mixed and stirred at 800-1200 rpm for 30-45 minutes at 120-150℃. S3. Extrusion granulation: The uniformly mixed material from step S2 is added to a twin-screw extruder and extruded into strips at 180-220℃ and a screw speed of 200-300 rpm. After cooling, the strips are granulated. S4. Pipe extrusion: Add the masterbatch obtained in step S3 into a single screw extruder and extrude the pipe at 190-230℃ and screw speed of 150-200 rpm, controlling the initial pipe wall thickness to be 0.2-0.5 mm. S5. Irradiation crosslinking: The nascent tube obtained in step S4 is subjected to irradiation crosslinking under vacuum conditions using a high-energy electron accelerator. The irradiation dose is 30-50 kGy, and the tube moves at a constant speed during the irradiation process. S6. Expansion and shaping: The tube irradiated in step S5 is placed in a specific mold, and compressed air of 0.3-0.5MPa is introduced at 120-140℃ to expand the tube radially to the target size. Then it is quickly cooled and shaped to obtain medical heat shrink tubing. S7, apply an anti-corrosion coating to the medical heat shrink tubing using an anti-corrosion coating equipment.

[0014] Preferably, in step S1, when the nano-sized inorganic particle reinforcing agent undergoes surface activation treatment, stearic acid or titanate coupling agent is added as a surfactant, and the treatment time is 2-3 hours.

[0015] Preferably, in step S4, the traction speed during pipe extrusion is controlled to be 1.2-1.5 m / min.

[0016] Preferably, in step S5, the vacuum degree during irradiation crosslinking is 10. -3 -10 -4 Pa, the pipe moving speed is 0.5-0.6m / min.

[0017] Preferably, in step S6, after expansion and shaping, the medical heat shrink tubing is cooled by cold water or air cooling, resulting in a shrinkage ratio of 1.8:1-2:1.

[0018] Preferably, it also includes the anti-corrosion coating equipment for heat shrink tubing in S7; The anti-corrosion coating device includes a base plate, with support plates fixedly connected to both sides of the bottom surface of the base plate. Each support plate has mounting holes. A bracket is fixedly connected to the center of the top surface of the base plate. A through pipe is fixedly connected to the top of the bracket. A heating coil is provided on the outer surface of the through pipe. An electric wire is fixedly connected to the through pipe. The other end of the electric wire is fixedly connected to a controller. A support rod is fixedly connected to the top of the base plate. A top plate is fixedly connected to the top of the support rod. A control panel is installed on the surface of the top plate. It also includes a transmission component, an anti-corrosion layer supply component, and a cooling and cleaning component. The transmission component is installed on the base plate for progressively advancing the heat shrink tubing. The anti-corrosion layer supply component is installed on the top plate for supplying liquid to the heated heat shrink tubing. The cooling and cleaning component is installed at the bottom of the top plate for centralized collection of particles.

[0019] Preferably, the transmission assembly includes a pair of first shaft seats fixedly mounted on the base plate, a rotating rod rotatably connected between the tops of the pair of first shaft seats, a rotating wheel fixedly connected to the middle of the rotating rod, and a first pulley fixedly connected to one end of the rotating rod; A first transmission belt is fitted onto the first pulley, and the other end of the first transmission belt is fitted onto the second pulley. The second pulley is fixedly connected to the transmission shaft, and a second shaft seat is fitted onto the transmission shaft. The bottom end of the second shaft seat is fixedly connected to the base plate, and the other end of the transmission shaft is fixedly connected to the output end of the first motor. The first motor is fixedly mounted on the base plate. A pair of first shaft seats are internally fixedly connected to a limiting block. A fixing rod is fixedly connected to the top surface of the limiting block. A docking seat is fixedly connected to the top of the fixing rod. A pulley is rotatably connected to the docking seat. A hinge seat is fixedly connected to the surface of the pulley. A rotating shaft is rotatably connected to the hinge seat. The rotating shaft is fixedly connected to a linkage seat. The other side of the linkage seat is fixedly connected to a wall panel. A clamping plate is fixedly connected to the top of the wall panel. A sponge pad is fixedly connected to the inner side of the clamping plate. The pulley is attached to the outer surface of the clamping plate.

[0020] Preferably, the wall panel has a through groove, and a guide rod is movably inserted into the through groove. One end of the guide rod is fixedly connected to the rotating wheel, and a sleeve is slidably connected to the guide rod. The sleeve is fixedly connected to the inside of the through groove, and the inner diameter of the sleeve is larger than the diameter of the guide rod. A baffle is fixedly connected to the other end of the guide rod, and a spring is sleeved on the guide rod. The two ends of the spring are fixedly connected to one side of the sleeve and one side of the baffle, respectively. The anti-corrosion layer provides components including a receiving groove formed on the top plate, a material collection port formed on the top plate, guide rails fixedly connected to both sides of the bottom surface of the material collection port, a collection box movably inserted inside the guide rails, a support plate fixedly connected to one side of the bottom surface of the receiving groove, a third shaft seat fixedly connected to the support plate, and a rotating ring rotatably connected to the third shaft seat. One end of the rotating ring is fixedly connected to a third pulley, a fixed seat is fixedly connected to the surface of the rotating ring, a cylinder is fixedly connected to the fixed seat, a connecting rod is fixedly inserted inside the cylinder, a transverse uniform coating component is fixedly connected to one end of the connecting rod, a second transmission belt is sleeved on the third pulley, the bottom end of the second transmission belt is sleeved on a fourth pulley, the fourth pulley is fixedly connected to the main shaft, one end of the main shaft is fixedly connected to the output end of a second motor, and the second motor is fixedly installed on the bottom surface of the pallet; The cooling cleaning assembly includes a welded component fixedly installed on the top surface of the top plate. A limiting ring is fixedly connected to the welded component. A docking ring is detachably installed on one side of the limiting ring. Several sets of anti-corrosion spray nozzles are fixedly connected to the inner wall of the docking ring. A fourth shaft seat is fixedly connected to both sides of the top surface near the top surface of the collection port on the top plate. A cooling pipe is rotatably connected to the fourth shaft seat. One end of the cooling pipe is fixedly connected to the output end of the third motor. The third motor is fixedly installed on the outside of the fourth shaft seat.

[0021] The beneficial effects of this invention are: This invention enhances the affinity with human tissues and reduces the risk of irritation to biological tissues by introducing corrosion-resistant groups (such as carboxyl and hydroxyl groups) into specially modified polyethylene. At the same time, the selected nano-sized inorganic particle reinforcing agent has minimal impact on biocompatibility due to its small size effect, and both antioxidants and plasticizers are made of environmentally friendly materials to avoid the release of harmful substances.

[0022] Verified through cytotoxicity tests and skin irritation tests, the heat shrink tubing is non-cytotoxic, non-irritating to the skin, fully meets the requirements for medical biocompatibility, and is suitable for use in medical devices that come into contact with the human body or are implanted.

[0023] The synergistic effect of thermoplastic polyurethane elastomer (Shore hardness 80A-85A) and environmentally friendly polyester plasticizer significantly improves the flexibility and elasticity of heat shrink tubing. Compared to traditional heat shrink tubing, this invention can easily wrap around a cylinder with a diameter of 2-3mm 4-5 times without breaking, and can well adapt to various complex-shaped medical device components (such as catheter bends and irregular connectors), solving the problems of poor fit and inconvenient operation caused by insufficient flexibility of existing heat shrink tubing.

[0024] After grafting modification, the molecular structure of the specially modified polyethylene is more stable. Combined with the uniform dispersion of nano-scale inorganic particle reinforcing agents (nano-titanium dioxide and calcium carbonate), a reinforced support system is formed, which effectively inhibits thermal deformation at high temperatures.

[0025] The irradiation cross-linking process creates a three-dimensional network structure in the tubing, further enhancing its thermal stability. After 30 minutes of high-pressure steam sterilization at 121°C, the dimensional change rate is less than 5%; after heating at 130°C for 2 hours, the dimensional change rate is less than 3%, far superior to traditional heat shrink tubing (which exhibits a dimensional change rate of over 15% after high-temperature treatment). It can withstand the high-temperature sterilization processes commonly used in the medical field, ensuring performance stability during long-term use.

[0026] One end of the heat shrink tubing is placed on a rotating wheel. The operation of the first motor causes the drive shaft to rotate, which in turn causes the second pulley to rotate. The rotation of the second pulley drives the first pulley to rotate via the first drive belt, which in turn facilitates the rotation of the rotating rod on the first pulley. The rotation of the rotating rod facilitates the rotation of the rotating wheel. When the clamping plate rotates to the top position, the pulley on the docking seat allows the sponge pad on the clamping plate to clamp the heat shrink tubing step by step. When the pulley disengages from the outer surface of the clamping plate, the clamping plate will retract due to the elastic force of the spring, thus allowing the sponge pad on the clamping plate to detach from the surface of the heat shrink tubing. One rotation of the rotating wheel can transport the heat shrink tubing. In this invention, when the heat shrink tubing enters the tube, the surface of the heat shrink tubing is heated by a heating coil to facilitate fusion with the anti-corrosion layer. Then, the heated heat shrink tubing enters the limiting ring, on which a docking ring is fixedly installed, and an anti-corrosion layer spray nozzle is fixedly connected to the inner wall of the docking ring. When the heat shrink tubing enters the limiting ring, the surface is longitudinally sprayed by the anti-corrosion layer spray nozzle. Then, the heat shrink tubing enters the rotating ring, and the operation of the second motor causes the fourth pulley on the main shaft to rotate. The rotation of the fourth pulley drives the rotating ring to rotate through the second transmission belt. The rotation of the rotating ring facilitates the transverse uniform coating of the heat shrink tubing by the transverse uniform coating component on the docking rod. In this invention, the coated heat shrink tubing skin passes through the collection port, and the particles on the heat shrink tubing skin fall into the collection box. However, some particles will adhere to the surface of the heat shrink tubing. Then, the third motor operates to rotate the cooling tube to cool the heat shrink tubing. The rotation of the cooling tube facilitates the removal of particles from the surface of the heat shrink tubing, avoiding the phenomenon of residual particles on the surface of the heat shrink tubing. The particles are collected in a collection box. Attached Figure Description

[0027] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of the three-dimensional structure of the device body; Figure 3 This is a side view of the three-dimensional structure of the device body; Figure 4 This is a schematic diagram of the three-dimensional structure of the transmission component; Figure 5 This is a three-dimensional structural diagram of the device body viewed from below. Figure 6 This is a top-view three-dimensional structural diagram of the pallet; Figure 7 This is a schematic diagram of the three-dimensional structure of the top slab; Figure 8 This is a schematic diagram of the three-dimensional structure of the limiting ring; Figure 9 for Figure 4 Enlarged structural diagram at point A in the middle; Figure 10 A linear graph showing the number of trees; Figure 11 This is a linear graph of the pile foundation depth.

[0028] In the diagram: 1. Base plate; 101. Support plate; 102. Mounting hole; 103. Bracket; 104. Through pipe; 105. Heating coil; 106. Wire; 107. Controller; 108. Support rod; 109. Top plate; 110. Control panel; 2. First shaft seat; 201. Rotating rod; 202. Rotating wheel; 203. First pulley; 204. First transmission belt; 205. Second pulley; 206. Transmission shaft; 207. Second shaft seat; 208. First motor; 3. Limiting block; 301. Fixing rod; 302. Connecting seat; 303. Pulley; 304. Hinge seat; 305. Rotating shaft; 306. Linkage seat; 307. Wall panel; 308. Clamping plate; 30 9. Sponge pad; 310. Through groove; 311. Guide rod; 312. Sleeve; 313. Baffle plate; 314. Spring; 4. Receiving groove; 401. Collection port; 402. Guide rail; 403. Collection box; 404. Pallet; 405. Third shaft seat; 406. Rotary ring; 407. Third pulley; 408. Fixed seat; 409. Insert; 410. Connecting rod; 411. Transverse uniform coating component; 412. Second transmission belt; 413. Fourth pulley; 414. Main shaft; 415. Second motor; 5. Welded component; 501. Limiting ring; 502. Connecting ring; 503. Anti-corrosion coating nozzle; 504. Fourth shaft seat; 505. Cooling pipe; 506. Third motor. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0030] It should be noted that all directional and positional terms used in this invention, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connections between components in a specific state (as shown in the accompanying drawings). They are merely for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0031] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0033] This medical heat shrink tubing is composed of the following components by weight percentage: Special modified polyethylene 40%-60%: Traditional polyethylene is grafted and modified to introduce corrosion-resistant groups, which enhances its compatibility with other components and its affinity with human tissues, while improving thermal stability.

[0034] 20%-35% thermoplastic polyurethane elastomer: provides good flexibility and elasticity, enabling heat shrink tubing to adapt to various complex shapes of medical device parts, and to shrink evenly during the heat shrinking process.

[0035] 5%-15% of nano-scale inorganic particle reinforcing agents, such as nano-titanium dioxide and nano-calcium carbonate, are uniformly dispersed in the heat shrink tubing matrix, significantly improving the strength and thermal stability of the heat shrink tubing. At the same time, due to the small size effect of nanoparticles, the impact on biocompatibility is minimal.

[0036] Antioxidant 0.5%-2%: Highly efficient hindered phenolic antioxidants are selected to effectively inhibit the oxidative degradation of heat shrink tubing during processing and use, thus extending its service life.

[0037] Plasticizer 3%-10%: Environmentally friendly polyester plasticizers are used to further enhance the flexibility and plasticity of heat shrink tubing and improve processing performance.

[0038] Preparation process steps: Raw material pretreatment: Specially modified polyethylene and thermoplastic polyurethane elastomers are dried at 80-100℃ for 4-6 hours to remove moisture, ensuring the dryness of the raw materials and preventing material performance degradation due to moisture during subsequent processing. Nanoscale inorganic particle reinforcing agents undergo surface activation treatment in a ball mill to increase their surface energy, making them easier to mix uniformly with other raw materials.

[0039] Mixing and stirring: Add the dried special modified polyethylene, thermoplastic polyurethane elastomer, surface-activated nano-sized inorganic particle reinforcing agent, antioxidant and plasticizer into a high-speed mixer according to the formula ratio, and mix and stir at 800-1200 rpm for 30-45 minutes at 120-150℃ to ensure that all components are fully and evenly mixed.

[0040] Extrusion granulation: The uniformly mixed material is added to a twin-screw extruder. The extruder temperature is set to 180-220℃ and the screw speed is 200-300 rpm. The material is extruded into strips through a specific die and then granulated after cooling in a water tank to obtain uniform masterbatch.

[0041] Pipe extrusion: Add the masterbatch to a single-screw extruder and extrude the pipe at 190-230℃. Control the screw speed at 150-200 rpm. By adjusting the traction speed and the temperature and pressure of the extruder, ensure the uniformity of the pipe wall thickness. The initial pipe wall thickness is controlled at 0.2-0.5mm.

[0042] Irradiation crosslinking: The nascent tubing is irradiated and crosslinked under vacuum conditions using a high-energy electron accelerator. The irradiation dose is controlled at 30-50 kGy. During the irradiation process, the tubing moves at a uniform speed to ensure uniform irradiation. Through irradiation crosslinking, a three-dimensional network structure is formed, which improves the thermal stability and mechanical properties of the heat shrink tubing.

[0043] Expansion and shaping: The irradiated tubing is expanded and shaped using an internal pressure blowing method. The tubing is placed in a specific mold, and compressed air is introduced at 120-140℃ with the pressure controlled at 0.3-0.5MPa to expand the tubing radially to the target size. Then, it is rapidly cooled and shaped to obtain a medical heat shrink tubing with a specific shrinkage ratio.

[0044] (I) Example 1 Material composition of heat shrink tubing Special modified polyethylene 50%: Modified by grafting carboxyl groups (-COOH) onto the polyethylene molecular chain, with a grafting rate of 5%.

[0045] 30% thermoplastic polyurethane elastomer: Shore hardness 80A.

[0046] 10% nano-titanium dioxide reinforcing agent: average particle size is 50nm.

[0047] Antioxidant 1%: Antioxidant 1010 is selected.

[0048] 9% plasticizer: polyester plasticizer.

[0049] Preparation process steps.

[0050] Raw material pretreatment: Special modified polyethylene and thermoplastic polyurethane elastomers are dried at 80℃ for 6 hours, and nano titanium dioxide is surface activated in a ball mill. Stearic acid is added as a surfactant, and the treatment time is 2 hours.

[0051] Mixing and stirring: Add each component to a high-speed mixer and mix and stir at 1000 rpm for 40 minutes at 130°C.

[0052] Extrusion granulation: The twin-screw extruder is set to a temperature of 200℃ and a screw speed of 250 rpm. The extrusion is done through a circular die to form strips, which are then cooled in a water tank and granulated.

[0053] Pipe extrusion: The temperature of the single screw extruder is 210℃, the screw speed is 180 rpm, the traction speed is controlled at 1.5m / min, and the initial pipe wall thickness is 0.3mm.

[0054] Irradiation crosslinking: Under a vacuum of 10⁻³ Pa, the tube is irradiated using a high-energy electron accelerator with an irradiation dose of 40 kGy and a tube moving speed of 0.5 m / min.

[0055] Expansion and shaping: The tubing is placed in a mold and expanded by introducing compressed air at a pressure of 0.4 MPa at 130°C. After expansion, it is quickly cooled and shaped in cold water to obtain a medical heat shrink tubing with a shrinkage ratio of 2:1.

[0056] The prepared heat shrink tubing was subjected to performance tests, and the results are as follows: In the flexibility test, the heat shrink tubing can be easily wrapped around a cylinder with a diameter of 2 mm 5 times without breaking; in the thermal stability test, after being sterilized by high-pressure steam at 121℃ for 30 minutes, the dimensional change rate of the heat shrink tubing is less than 5%, with no deformation or performance degradation; in the biocompatibility test, through cytotoxicity tests and skin irritation tests, the results show that it has no cytotoxicity and no skin irritation.

[0057] (II) Example 2 Material composition of heat shrink tubing Special modified polyethylene 45%: grafted hydroxyl groups (-OH), grafting rate 8%.

[0058] 25% thermoplastic polyurethane elastomer: Shore hardness 85A.

[0059] 12% nano-calcium carbonate reinforcing agent: average particle size is 80nm.

[0060] Antioxidant 1.5%: Antioxidant 168.

[0061] Plasticizer 6.5%: Polyester plasticizer.

[0062] Preparation process steps Raw material pretreatment: Drying temperature is 90℃, time is 5 hours, and titanate coupling agent is added during the surface activation treatment of nano calcium carbonate, and the treatment time is 3 hours.

[0063] Mixing and stirring: Mixing temperature 140℃, speed 1100 rpm, stirring time 35 minutes.

[0064] Extrusion granulation: Twin-screw extruder temperature 210℃, screw speed 280 rpm, die head is square.

[0065] Pipe extrusion: Single screw extruder temperature 220℃, screw speed 160 rpm, traction speed 1.2 m / min, initial pipe wall thickness 0.4 mm.

[0066] Irradiation crosslinking: vacuum degree 10⁻⁴ Pa, irradiation dose 35 kGy, pipe moving speed 0.6 m / min.

[0067] Expansion and shaping: Temperature 125℃, compressed air pressure 0.35MPa, after expansion, air cooling and shaping are performed to obtain medical heat shrink tubing with a shrinkage ratio of 1.8:1.

[0068] Performance test results: Good flexibility, can be wrapped around a cylinder with a diameter of 3mm 4 times; In terms of thermal stability, after heating at 130℃ for 2 hours, the dimensional change rate is less than 3%; Good biocompatibility, all biological test indicators are qualified.

[0069] (iii) Comparative Example 1 Heat shrink tubing is prepared using conventional processes with 60% unmodified polyethylene, 10% ordinary plasticizer, no nano-reinforcing agent, 0.5% ordinary antioxidant, and the remainder being thermoplastic polyurethane elastomer.

[0070] Performance tests revealed poor flexibility; it broke after being wrapped around a 2mm diameter cylinder twice. It also showed insufficient thermal stability; after being sterilized by high-pressure steam at 121℃, the dimensional change rate reached 15%, and deformation occurred. In the biocompatibility test, the cytotoxicity test showed slight cytotoxicity.

[0071] (iv) Comparative Example 2 The same materials as in Example 1 were used, but the preparation process employed an optimized method of conventional simple mixing, ordinary extrusion, radiation-free crosslinking, and expansion and shaping.

[0072] Test results showed that the heat shrink tubing had low strength and was prone to breakage; its thermal stability was poor, with significant dimensional changes after heating at 100°C for 1 hour; its flexibility was also inferior to the product of Example 1; and although there were no obvious adverse reactions in terms of biocompatibility, its overall performance was far lower than that of the product of Example 1.

[0073] By comparing the embodiments and comparative examples, it can be clearly seen that the medical heat shrink tubing and its preparation process of the present invention have significant advantages in terms of flexibility, thermal stability and biocompatibility.

[0074] Furthermore, this invention achieves various application requirements such as self-cleaning, anti-fogging, lubrication, corrosion prevention, and biocompatibility by applying an anti-corrosion coating to medical heat shrink tubing using an anti-corrosion coating device; the specific device used is as follows; The system includes a base plate 1, with support plates 101 fixedly connected to both sides of the bottom surface of the base plate 1. Each support plate 101 has mounting holes 102. A bracket 103 is fixedly connected to the center of the top surface of the base plate 1. A through pipe 104 is fixedly connected to the top of the bracket 103. A heating coil 105 is provided on the outer surface of the through pipe 104. An electric wire 106 is fixedly connected to the through pipe 104. The other end of the electric wire 106 is fixedly connected to a controller 107. A support rod 108 is fixedly connected to the top of the base plate 1. A top plate 109 is fixedly connected to the top of the support rod 108. A control panel 110 is installed on the surface of the top plate 109. The system also includes a transmission component, an anti-corrosion layer supply component, and a cooling and cleaning component. The transmission component is installed on the base plate 1 for progressively advancing the heat shrink tubing. The anti-corrosion layer supply component is installed on the top plate 109 to supply liquid to the heated heat shrink tubing. The cooling and cleaning component is installed at the bottom of the top plate 109 to cool and cure the heat shrink tubing and clean surface particles.

[0075] Specifically, it should be noted that the control panel 110, the first motor 208, the second motor 415, and the third motor 506 are all electrically connected by wires. The specific working principles of each are based on existing technology and will not be elaborated on here. The first motor 208 transmits heat shrink tubing, the second motor 415 evenly coats the outer layer of the heat shrink tubing, and finally the third motor 506 sweeps the particles attached to the surface of the heat shrink tubing into the collection box 403 for centralized collection.

[0076] In one embodiment of this invention, the transmission assembly includes a pair of first bearing seats 2 fixedly mounted on a base plate 1. A rotating rod 201 is rotatably connected between the tops of the pair of first bearing seats 2. A rotating wheel 202 is fixedly connected to the middle of the rotating rod 201. A first pulley 203 is fixedly connected to one end of the rotating rod 201. A first transmission belt 204 is sleeved on the first pulley 203. The other end of the first transmission belt 204 is sleeved on a second pulley 205. The second pulley 205 is fixedly connected to a transmission shaft 206. A second bearing seat 207 is sleeved on the transmission shaft 206. The bottom end of the second bearing seat 207 is fixedly connected to the base plate 1. The other end of the transmission shaft 206 is fixedly connected to the output end of a first motor 208. The first motor 208 is fixedly mounted on the base plate 1. A limiting block 3 is fixedly connected inside the pair of first bearing seats 2. A fixing rod 301 is fixedly connected to the top surface of the limiting block 3. A docking seat 302 is fixedly connected to the top of the fixing rod 301. A pulley is rotatably connected to the docking seat 302. 303, a hinge seat 304 is fixedly connected to the surface of the rotating wheel 202, a rotating shaft 305 is rotatably connected to the hinge seat 304, the rotating shaft 305 is fixedly connected to the linkage seat 306, the other side of the linkage seat 306 is fixedly connected to the wall plate 307, a clamping plate 308 is fixedly connected to the top of the wall plate 307, a sponge pad 309 is fixedly connected to the inner side of the clamping plate 308, the pulley 303 is attached to the outer surface of the clamping plate 308, and a through groove 310 is formed on the wall plate 307, the inner side of the through groove 310... A guide rod 311 is inserted into the part. One end of the guide rod 311 is fixedly connected to the rotating wheel 202. A sleeve 312 is slidably connected to the guide rod 311. The sleeve 312 is fixedly connected inside the through groove 310. The inner diameter of the sleeve 312 is larger than the diameter of the guide rod 311. A baffle 313 is fixedly connected to the other end of the guide rod 311. A spring 314 is sleeved on the guide rod 311. The two ends of the spring 314 are fixedly connected to one side of the sleeve 312 and one side of the baffle 313, respectively.

[0077] Specifically, one end of the heat shrink tubing is placed on the rotating wheel 202. The operation of the first motor 208 causes the drive shaft 206 to rotate, which in turn causes the second pulley 205 to rotate. The rotation of the second pulley 205 drives the first pulley 203 to rotate via the first drive belt 204, thus facilitating the rotation of the rotating rod 201 on the first pulley 203. The rotation of the rotating rod 201 facilitates the rotation of the rotating wheel 202. When the clamping plate 308 rotates to the top position, the pulley 303 on the docking seat 302 facilitates the sponge pad 309 on the clamping plate 308 to clamp the heat shrink tubing step by step. When the pulley 303 disengages from the outer surface of the clamping plate 308, the clamping plate 308 will retract the wall plate 307 on the sleeve 312 due to the elastic force of the spring 314, thus facilitating the sponge pad 309 on the clamping plate 308 to cover the surface of the heat shrink tubing. One rotation of the rotating wheel 202 can transfer the heat shrink tubing.

[0078] In one embodiment of this invention, the anti-corrosion layer providing component includes a receiving groove 4 formed on a top plate 109. A collection port 401 is formed on the top plate 109. Guide rails 402 are fixedly connected to both sides of the bottom surface of the collection port 401. A collection box 403 is movably inserted inside the guide rails 402. A support plate 404 is fixedly connected to one side of the bottom surface of the receiving groove 4. A third bearing 405 is fixedly connected to the support plate 404. A rotating ring 406 is rotatably connected to the third bearing 405. A third pulley 407 is fixedly connected to one end of the rotating ring 406. The surface of the rotating ring 406 is fixed... A fixed base 408 is fixedly connected to the fixed base 408, and an insert 409 is fixedly connected to the fixed base 408. A connecting rod 410 is fixedly inserted inside the insert 409. A transverse uniform coating component 411 is fixedly connected to one end of the connecting rod 410. A second transmission belt 412 is sleeved on the third pulley 407. The bottom end of the second transmission belt 412 is sleeved on the fourth pulley 413. The fourth pulley 413 is fixedly connected to the main shaft 414. One end of the main shaft 414 is fixedly connected to the output end of the second motor 415. The second motor 415 is fixedly installed on the bottom surface of the support plate 404.

[0079] Specifically, when the heat shrink tubing enters the tube 104, the surface of the heat shrink tubing is heated by the heating coil 105, making it easier for subsequent coating to adhere to the outer surface of the heat shrink tubing. Then, the heated heat shrink tubing enters the limiting ring 501. A docking ring 502 is fixedly installed on the limiting ring 501, and an anti-corrosion spray nozzle 503 is fixedly connected to the inner wall of the docking ring 502. When the heat shrink tubing enters the limiting ring 501, the surface is sprayed longitudinally by the anti-corrosion spray nozzle 503. Then, the heat shrink tubing enters the rotating ring 406. The operation of the second motor 415 causes the fourth pulley 413 on the main shaft 414 to rotate. The rotation of the fourth pulley 413 drives the rotating ring 406 to rotate through the second transmission belt 412. The rotation of the rotating ring 406 facilitates the transverse uniform coating component 411 on the docking rod 410 to apply the anti-corrosion coating to the heat shrink tubing in a transverse and uniform manner, thereby facilitating the application of the anti-corrosion coating to the heat shrink tubing.

[0080] As one embodiment of this invention, the cooling and cleaning assembly includes a welded component 5 fixedly installed on the top surface of the top plate 109. A limiting ring 501 is fixedly connected to the welded component 5. A docking ring 502 is detachably installed on one side of the limiting ring 501. Several sets of anti-corrosion spray nozzles 503 are fixedly connected to the inner wall of the docking ring 502. A fourth bearing 504 is fixedly connected to both sides of the top surface of the top plate 109 near the top surface of the collection port 401. A cooling pipe 505 is rotatably connected to the fourth bearing 504. One end of the cooling pipe 505 is fixedly connected to the output end of the third motor 506. The third motor 506 is fixedly installed on the outside of the fourth bearing 504.

[0081] Specifically, after the anti-corrosion layer is applied, the surface of the heat shrink tubing will pass through the collection port 401, and the cleaned particles will fall into the collection box 403. However, some particles will adhere to the surface of the heat shrink tubing. Then, the third motor 506 will operate to rotate the cooling tube 505. The rotation of the cooling tube 505 will help to knock off the particles on the surface of the heat shrink tubing, avoiding the phenomenon of residual particles on the surface of the heat shrink tubing. The particles will be collected in the collection box 403. At the same time, the cooling tube 505 will simultaneously cool the outside of the heat shrink tubing to efficiently cure the anti-corrosion layer.

[0082] Working principle of the invention: One end of the heat shrink tubing is placed on the rotating wheel 202. The operation of the first motor 208 causes the transmission shaft 206 to rotate. The rotation of the transmission shaft 206 causes the second pulley 205 to rotate. The rotation of the second pulley 205 drives the first pulley 203 to rotate through the first transmission belt 204, thereby facilitating the rotation of the rotating rod 201 on the first pulley 203. The rotation of the rotating rod 201 facilitates the rotation of the rotating wheel 202. When the clamping plate 308 rotates to the top position, the pulley 303 on the docking seat 302 facilitates the sponge pad 309 on the clamping plate 308 to clamp the heat shrink tubing step by step. When the pulley 303 disengages from the outer surface of the clamping plate 308, the clamping plate 308 will drive the wall plate 307 on the sleeve 312 to retract through the elastic force of the spring 314, thereby facilitating the sponge pad 309 on the clamping plate 308 to disengage from the surface of the heat shrink tubing. The rotating wheel 202 can transfer the heat shrink tubing by rotating one revolution. When the heat shrink tubing enters the tube 104, the surface of the heat shrink tubing is heated by the heating coil 105. After heating, the heat shrink tubing enters the limiting ring 501. A docking ring 502 is fixedly installed on the limiting ring 501, and an anti-corrosion spray nozzle 503 is fixedly connected to the inner wall of the docking ring 502. When the heat shrink tubing enters the limiting ring 501, the surface is sprayed longitudinally by the anti-corrosion spray nozzle 503. Then the heat shrink tubing enters the rotating ring 406. The operation of the second motor 415 causes the fourth pulley 413 on the main shaft 414 to rotate. The rotation of the fourth pulley 413 drives the rotating ring 406 to rotate through the second transmission belt 412. The rotation of the rotating ring 406 facilitates the transverse uniform coating part 411 on the docking rod 410 to apply transverse uniform coating to the heat shrink tubing. After the anti-corrosion layer is applied, the surface of the heat shrink tubing will fall into the collection box 403 through the collection port 401. However, some particles will stick to the surface of the heat shrink tubing. Then, the third motor 506 will operate to make the cooling tube 505 rotate. The rotation of the cooling tube 505 will help to knock off the particles on the surface of the heat shrink tubing, avoiding the phenomenon of residual particles on the surface of the heat shrink tubing. The particles will be collected in the collection box 403.

[0083] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A medical heat shrink tubing, characterized in that: It is composed of the following components by weight percentage: 40%-60% special modified polyethylene, 20%-35% thermoplastic polyurethane elastomer, 5%-15% nano-sized inorganic particle reinforcing agent, 0.5%-2% antioxidant, and 3%-10% plasticizer; The specially modified polyethylene is grafted modified polyethylene with introduced anti-corrosion groups, the nano-scale inorganic particle reinforcing agent is nano-titanium dioxide or nano-calcium carbonate, the antioxidant is hindered phenolic antioxidant, and the plasticizer is environmentally friendly polyester plasticizer.

2. The medical heat shrink tubing according to claim 1, characterized in that: The specially modified polyethylene is modified by grafting carboxyl groups (-COOH) or hydroxyl groups (-OH) onto the polyethylene molecular chain, with a grafting rate of 5%-8%.

3. A medical heat shrink tubing according to claim 2, characterized in that: The Shore hardness of the thermoplastic polyurethane elastomer is 80A-85A.

4. A medical heat shrink tubing according to claim 3, characterized in that: The average particle size of the nanoscale inorganic particle reinforcing agent is 50nm-80nm.

5. A medical heat shrink tubing according to claim 4, characterized in that: The antioxidant is antioxidant 1010 or antioxidant 168.

6. A process for manufacturing medical heat shrink tubing, based on the medical heat shrink tubing described in claims 1-5, characterized in that: Includes the following steps: S1. Dry the specially modified polyethylene and thermoplastic polyurethane elastomer at 80-100℃ for 4-6 hours; perform surface activation treatment on the nano-sized inorganic particle reinforcing agent in a ball mill; S2. According to the mass percentage described in claim 1, the specially modified polyethylene, thermoplastic polyurethane elastomer, nano-sized inorganic particle reinforcing agent, antioxidant, and plasticizer treated in step S1 are added to a high-speed mixer and mixed and stirred at 800-1200 rpm for 30-45 minutes at 120-150°C. S3. Add the uniformly mixed material from step S2 into a twin-screw extruder, and extrude it into strips at 180-220℃ and a screw speed of 200-300 rpm. After cooling, cut it into pellets. S4. Add the masterbatch obtained in step S3 into a single-screw extruder and extrude the pipe at 190-230℃ and screw speed of 150-200 rpm, controlling the initial pipe wall thickness to be 0.2-0.5 mm. S5. The nascent tube obtained in step S4 is subjected to cross-linking by irradiation using a high-energy electron accelerator under vacuum conditions. The irradiation dose is 30-50 kGy, and the tube moves at a constant speed during the irradiation process. S6. Place the irradiated tubing from step S5 into a specific mold, and introduce compressed air at 0.3-0.5MPa at 120-140℃ to radially expand the tubing to the target size. Then, rapidly cool and shape it to obtain medical heat shrink tubing. S7, apply an anti-corrosion coating to the medical heat shrink tubing using an anti-corrosion coating equipment.

7. The manufacturing process of a medical heat shrink tubing according to claim 6, characterized in that: In step S1, when the nano-sized inorganic particle reinforcing agent undergoes surface activation treatment, stearic acid or titanate coupling agent is added as a surfactant, and the treatment time is 2-3 hours. In step S4, the traction speed during pipe extrusion is controlled at 1.2-1.5 m / min; In step S5, the vacuum degree during irradiation crosslinking is 10. -3 -10 -4 Pa, the pipe moving speed is 0.5-0.6 m / min; In step S6, after expansion and shaping, the tube is cooled by cold water or air cooling, resulting in a shrinkage ratio of 1.8:1-2:1 for the medical heat shrink tubing.

8. The manufacturing process of a medical heat shrink tubing according to claim 7, characterized in that: It also includes the anti-corrosion coating equipment for heat shrink tubing in S7; The anti-corrosion coating device includes a base plate (1), characterized in that a support plate (101) is fixedly connected to both sides of the bottom surface of the base plate (1), and mounting holes (102) are provided on the support plate (101). A bracket (103) is fixedly connected to the middle of the top surface of the base plate (1), and a through pipe (104) is fixedly connected to the top of the bracket (103). A heating coil (105) is provided on the outer surface of the through pipe (104), and an electric wire (106) is fixedly connected to the through pipe (104). The other end of the electric wire (106) is fixedly connected to a controller (107). A support rod (108) is fixedly connected to the top of the base plate (1), and a top plate (109) is fixedly connected to the top of the support rod (108). A control panel (110) is installed on the surface of the top plate (109). It also includes a transmission component, an anti-corrosion layer supply component, and a cooling cleaning component. The transmission component is installed on the base plate (1) for progressively advancing the heat shrink tubing. The anti-corrosion layer supply component is installed on the top plate (109) for supplying liquid to the heated heat shrink tubing. The cooling cleaning component is installed at the bottom of the top plate (109) for centralized collection of particles.

9. The manufacturing process of a medical heat shrink tubing according to claim 8, characterized in that: The transmission assembly includes a pair of first bearings (2) fixedly mounted on the base plate (1), a rotating rod (201) is rotatably connected between the tops of the pair of first bearings (2), a rotating wheel (202) is fixedly connected to the middle position of the rotating rod (201), and a first pulley (203) is fixedly connected to one end of the rotating rod (201). A first transmission belt (204) is fitted on the first pulley (203), and the other end of the first transmission belt (204) is fitted on the second pulley (205). The second pulley (205) is fixedly connected to the transmission shaft (206). A second shaft seat (207) is fitted on the transmission shaft (206). The bottom end of the second shaft seat (207) is fixedly connected to the base plate (1). The other end of the transmission shaft (206) is fixedly connected to the output end of the first motor (208). The first motor (208) is fixedly installed on the base plate (1). A limiting block (3) is fixedly connected inside a pair of first shaft seats (2). A fixing rod (301) is fixedly connected to the top surface of the limiting block (3). A docking seat (302) is fixedly connected to the top of the fixing rod (301). A pulley (303) is rotatably connected to the docking seat (302). A hinge seat (304) is fixedly connected to the surface of the wheel (202). A rotating shaft (305) is rotatably connected to the hinge seat (304). The rotating shaft (305) is fixedly connected to the linkage seat (306). The other side of the linkage seat (306) is fixedly connected to the wall panel (307). A clamping plate (308) is fixedly connected to the top of the wall panel (307). A sponge pad (309) is fixedly connected to the inner side of the clamping plate (308). The pulley (303) is attached to the outer surface of the clamping plate (308).

10. The manufacturing process of a medical heat shrink tubing according to claim 1, characterized in that: The wall panel (307) has a through groove (310), and a guide rod (311) is movably inserted inside the through groove (310). One end of the guide rod (311) is fixedly connected to the rotating wheel (202), and a sleeve (312) is slidably connected to the guide rod (311). The sleeve (312) is fixedly connected inside the through groove (310), and the inner diameter of the sleeve (312) is larger than the diameter of the guide rod (311). The other end of the guide rod (311) is fixedly connected to a baffle (313), and a spring (314) is sleeved on the guide rod (311). The two ends of the spring (314) are fixedly connected to one side of the sleeve (312) and one side of the baffle (313), respectively. The anti-corrosion layer providing component includes a receiving groove (4) opened on the top plate (109), a material collection port (401) opened on the top plate (109), guide rails (402) fixedly connected to both sides of the bottom surface of the material collection port (401), a collection box (403) movably inserted inside the guide rails (402), a support plate (404) fixedly connected to one side of the bottom surface of the receiving groove (4), a third shaft seat (405) fixedly connected to the support plate (404), and a rotating ring (406) rotatably connected to the third shaft seat (405). One end of the rotating ring (406) is fixedly connected to a third pulley (407), and a fixed seat (408) is fixedly connected to the surface of the rotating ring (406). A tube (409) is fixedly connected to the fixed seat (408), and a connecting rod (410) is fixedly inserted inside the tube (409). One end of the connecting rod (410) is fixedly connected to a transverse uniform coating component (411). A second transmission belt (412) is sleeved on the third pulley (407), and the bottom end of the second transmission belt (412) is sleeved on a fourth pulley (413). The fourth pulley (413) is fixedly connected to the main shaft (414), and one end of the main shaft (414) is fixedly connected to the output end of a second motor (415). The second motor (415) is fixedly installed on the bottom surface of the pallet (404). The cooling cleaning assembly includes a welded part (5) fixedly installed on the top surface of the top plate (109). A limiting ring (501) is fixedly connected to the welded part (5). A docking ring (502) is detachably installed on one side of the limiting ring (501). Several sets of anti-corrosion spray nozzles (503) are fixedly connected to the inner wall of the docking ring (502). A fourth bearing seat (504) is fixedly connected to both sides of the top surface of the top plate (109) near the top surface of the collection port (401). A cooling pipe (505) is rotatably connected to the fourth bearing seat (504). One end of the cooling pipe (505) is fixedly connected to the output end of the third motor (506). The third motor (506) is fixedly installed on the outside of the fourth bearing seat (504).

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