A soft and hard segment alternating composite medical interventional pipe material and a preparation method thereof

Abstract

The application relates to the technical field of medical polymers, and discloses a soft-hard segment alternating composite medical interventional pipe material and a preparation method thereof. The preparation method comprises the following steps: respectively preparing a soft segment prepolymer with end-NCO groups and a hard segment prepolymer, alternately adding the two in a mass ratio of 1:0.8-1:1.2 into a same-direction double-screw reaction extruder, in-situ polymerizing at 140 DEG C-190 DEG C to form a pipe blank with a soft-hard segment alternating structure, and then performing gradient cooling, plasma surface grafting modification and sterile packaging to obtain the pipe material. By adopting a specific molecular weight polyol and diisocyanate ratio in the soft-hard segment prepolymer preparation stage and combining a double-screw alternating copolymerization process, the pipe material pipe wall body is formed into a soft-hard segment alternating composite structure along the axial direction, and the soft segment and the hard segment are connected through chemical bonding. The application realizes the soft-hard segment alternating composite of the pipe material pipe wall along the axial direction, and improves the subsequent processing adaptability and interface bonding reliability of the pipe material.

Description

Technical Field

[0001] This invention relates to the field of medical polymer technology, specifically to a composite medical interventional tubing with alternating soft and hard segments and its preparation method. Background Technology

[0002] Medical polymers refer to polymers that are pharmacologically inert, mainly covering artificial organs, drug carriers, and medical devices.

[0003] Currently, the preparation process of alternating soft and hard segment composite medical interventional tubing involves multiple steps of prepolymerization, alternating copolymerization, and post-processing. During the alternating copolymerization reaction of the soft and hard segment prepolymers, it is difficult to accurately control the addition interval and mixing uniformity of the two, and it is impossible to monitor the degree of interfacial reaction in the co-rotating twin-screw reactive extruder in real time. When the timing of alternating addition is off or the mixing is uneven, the chemical bonding strength between the soft and hard segments will be insufficient, and the stability of the tubing structure cannot be guaranteed. At the same time, during the gradient cooling treatment of the tubing blank, it is impossible to detect the fluctuation of the cooling temperature of each segment in real time, which will cause uneven distribution of residual stress inside the tubing. Moreover, the temperature deviation during the cooling process cannot be corrected in time, which will lead to warping or a decrease in dimensional accuracy of the tubing.

[0004] Therefore, a composite medical interventional tubing with alternating soft and hard segments 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 composite medical interventional tubing with alternating soft and hard segments and its preparation method, which solves the problems mentioned in the background art, namely, the inability to monitor the degree of interfacial reaction in a co-rotating twin-screw reactive extruder in real time, and the inability to detect the fluctuation of cooling temperature in each segment in real time.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a composite medical interventional tubing with alternating soft and hard segments and its preparation method, comprising the following steps: Step S1: Preparation of soft segment prepolymer: Polyether diol with a number average molecular weight of 800-1200 is mixed with diisocyanate at a molar ratio of 1:1.05-1:1.2 and catalytically reacted at 70℃-80℃ for 2-3 hours under nitrogen protection to obtain a soft segment prepolymer with terminal -NCO groups. Step S2: Preparation of hard segment prepolymer: A chain extender with a number average molecular weight of 200-400 is mixed with diisocyanate at a molar ratio of 1:2-1:3 and catalytically reacted at 80℃-90℃ for 1-2 hours under nitrogen protection to obtain a hard segment prepolymer with terminal -NCO groups. Step S3: Alternating copolymerization reaction. Soft segment prepolymer and hard segment prepolymer are alternately added to a co-rotating twin-screw reactive extruder at a mass ratio of 1:0.8-1:1.2. The barrel temperature is controlled at 140℃-190℃ and the screw speed is 30rpm-50rpm. In-situ polymerization is used to form a tube blank with an alternating soft and hard segment structure. Step S4: Post-processing and shaping. The tube blank is subjected to gradient cooling, plasma surface grafting modification and aseptic packaging in sequence to obtain the soft and hard segment alternating composite medical interventional tubing.

[0007] Preferably, the polyether diol in step S1 is selected from one or a combination of two of polytetrahydrofuran ether diol and polypropylene oxide diol, the diisocyanate is selected from one or a combination of 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, and the catalyst used for the catalytic reaction is dibutyltin dilaurate, with an addition amount of 0.01%-0.05% of the total mass of the reaction system.

[0008] Preferably, the chain extender in step S2 is selected from one or more combinations of 1,4-butanediol, 1,6-hexanediol, and diethyl terephthalate, and the catalyst used for the catalytic reaction is stannous octoate, with an addition amount of 0.02%-0.08% of the total mass of the reaction system.

[0009] Preferably, the co-rotating twin-screw reactive extruder in step S3 is divided into a preheating section, a mixing section, a reaction section, and an extrusion section along the material flow direction. The temperature of the preheating section is 140℃-150℃, the temperature of the mixing section is 160℃-170℃, the temperature of the reaction section is 175℃-185℃, and the temperature of the extrusion section is 180℃-190℃. The interval between the alternating addition of soft segment prepolymer and hard segment prepolymer is 5min-10min. The shearing action of the twin screw achieves a strong chemical bond at the interface of the two phases.

[0010] Preferably, the gradient cooling in step S4 adopts a three-stage temperature control: the first stage cooling temperature is 120℃-130℃, the second stage cooling temperature is 80℃-90℃, and the third stage cooling temperature is 25℃-35℃, with each stage cooling time being 10min-15min, and the cooling medium being deionized water or ethylene glycol aqueous solution.

[0011] Preferably, the plasma surface grafting modification in step S4 is performed in a vacuum reaction chamber, specifically as follows: Place the tube blank in the chamber and evacuate until... A mixture of argon and acrylic acid monomers is introduced, with a volume ratio of argon to acrylic acid of 3:1-5:1. An RF plasma generator is used, with a power set to 100W-300W and a processing time of 5-10 minutes, to introduce carboxyl functional groups onto the surface of the pipe.

[0012] Preferably, in the in-situ polymerization process described in step S3, 0.5%-1.5% of nano-reinforcing filler is added, which accounts for 0.5%-1.5% of the total mass of the reaction system. The nano-reinforcing filler is selected from one or more combinations of nano-silica, nano-hydroxyapatite, and carbon nanotubes, with a particle size of 10nm-50nm. After being surface modified by silane coupling agent KH-570, it is dispersed in the hard segment prepolymer.

[0013] Preferably, the catalytic reactions in steps S1 and S2 are accompanied by ultrasonic-assisted dispersion, with an ultrasonic frequency of 40kHz-60kHz, a power of 200W-400W, and a dispersion time of 20min-30min, to promote full contact between the isocyanate groups and the hydroxyl groups.

[0014] Preferably, before the aseptic packaging described in step S4, an irradiation sterilization step is further included, using gamma rays or electron beam irradiation with an irradiation dose of 15kGy-25kGy to ensure that the pipe material reaches a certain sterility level. .

[0015] Preferably, a composite medical interventional tubing with alternating soft and hard segments includes a tubing body. The tubing body has an axially alternating soft and hard segment composite structure, with the soft segments and hard segments connected by chemical bonding. The glass transition temperature of the soft segments is -40℃ to -20℃, the glass transition temperature of the hard segments is 50℃ to 80℃, the outer diameter of the tubing is 0.5mm to 10mm, and the wall thickness is 0.05mm to 0.5mm.

[0016] Compared with the prior art, the present invention provides a composite medical interventional tubing with alternating soft and hard segments and its preparation method, which has the following beneficial effects: 1. In this invention, when preparing a medical interventional tubing with alternating soft and hard segments, the alternating addition sequence of the soft segment prepolymer and the hard segment prepolymer, along with the segmented temperature control parameters of the co-rotating twin-screw reactive extruder, ensures that the soft and hard segments are uniformly dispersed and fully reacted during in-situ polymerization. This allows for real-time monitoring of the bonding state at the interface between the two phases, avoiding interface bonding defects caused by deviations in the timing of alternating addition or uneven mixing. This ensures the stability of the axial alternating soft and hard segment composite structure of the tubing and achieves the alternating soft and hard segment composite structure along the axial direction of the tubing wall.

[0017] 2. In this invention, during the post-processing and shaping of the tube blank, a gradient cooling process is executed and the temperature fluctuation of the cooling medium in each section is monitored in real time. The cooling rate is dynamically adjusted to match the stress release process inside the tube. This allows for real-time detection of any temperature anomalies during the cooling process, enabling the system to correct the cooling parameters in time before the tube warps or deviates in size. This reduces the risk of structural deformation caused by residual stress concentration and ensures the dimensional accuracy of the tube's outer diameter and wall thickness.

[0018] 3. In this invention, when performing plasma surface grafting modification on the pipe, the proportion of gas components and radio frequency power parameters in the reaction chamber are dynamically controlled, and the introduction density and distribution of surface functional groups are monitored in real time. The treatment intensity can be adjusted according to the real-time response of the pipe surface, avoiding differences in modification effect caused by parameter fluctuations. This makes the chemical structure of the grafted layer on the pipe surface more uniform, improving the subsequent processing adaptability and interface bonding reliability of the pipe. Detailed Implementation

[0019] 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.

[0020] Example 1: A composite medical interventional tubing with alternating soft and hard segments and its preparation method, comprising the following steps: Step S1: Preparation of soft segment prepolymer: Polyether diol with a number average molecular weight of 800 and diisocyanate are mixed at a molar ratio of 1:1.05 and catalytically reacted at 70°C for 2 hours under nitrogen protection to obtain a soft segment prepolymer with terminal -NCO groups. Step S2: Preparation of hard segment prepolymer: A chain extender with a number average molecular weight of 200 is mixed with diisocyanate at a molar ratio of 1:2 and catalytically reacted at 80°C for 1 hour under nitrogen protection to obtain a hard segment prepolymer with terminal -NCO groups. Step S3: Alternating copolymerization reaction. The soft segment prepolymer and hard segment prepolymer are alternately added to the co-rotating twin-screw reactive extruder at a mass ratio of 1:0.8. The barrel temperature is controlled at 140℃-190℃ and the screw speed is 30rpm. The tube blank with alternating soft and hard segment structure is formed by in-situ polymerization. Step S4: Post-processing and shaping. The tube blank is subjected to gradient cooling, plasma surface grafting modification and aseptic packaging in sequence to obtain the soft and hard segment alternating composite medical interventional tubing.

[0021] In step S1, the polyether diol is polytetrahydrofuran ether diol, the diisocyanate is a combination of 4,4'-diphenylmethane diisocyanate and hexamethylene diisocyanate, and the catalyst used in the catalytic reaction is dibutyltin dilaurate, with an addition amount of 0.01% of the total mass of the reaction system.

[0022] In step S2, the chain extender is a combination of 1,4-butanediol and 1,6-hexanediol, and the catalyst used for the catalytic reaction is stannous octoate, with an addition amount of 0.02% of the total mass of the reaction system.

[0023] In step S3, the co-rotating twin-screw reactive extruder is divided into a preheating section, a mixing section, a reaction section, and an extrusion section along the material flow direction. The temperature of the preheating section is 140℃, the temperature of the mixing section is 160℃, the temperature of the reaction section is 175℃, and the temperature of the extrusion section is 180℃. The interval between the alternating addition of soft segment prepolymer and hard segment prepolymer is 5 minutes. The shearing action of the twin screw achieves a strong chemical bond at the interface of the two phases.

[0024] In step S4, gradient cooling adopts a three-stage temperature control: the first stage cooling temperature is 120℃, the second stage cooling temperature is 80℃, and the third stage cooling temperature is 25℃. The cooling time for each stage is 10 minutes, and the cooling medium is deionized water.

[0025] Step S4, plasma surface grafting modification, is carried out in a vacuum reaction chamber, specifically as follows: Place the tube blank in the chamber and evacuate until... A mixture of argon and acrylic acid monomers is introduced, with a volume ratio of argon to acrylic acid of 3:1. An RF plasma generator is used, with a power of 100W and a processing time of 5 minutes, to introduce carboxyl functional groups onto the surface of the pipe.

[0026] In step S3, during the in-situ polymerization process, 0.5% of the total mass of the reaction system of nano-reinforcing filler is added. The nano-reinforcing filler is a combination of nano-silica and nano-hydroxyapatite with a particle size of 10 nm. After surface modification with silane coupling agent KH-570, it is dispersed in the hard segment prepolymer.

[0027] In both steps S1 and S2, the catalytic reaction was accompanied by ultrasonic-assisted dispersion. The ultrasonic frequency was 40 kHz, the power was 200 W, and the dispersion time was 20 min, which promoted the full contact between the isocyanate groups and the hydroxyl groups.

[0028] Before aseptic packaging in step S4, an irradiation sterilization step is also included, using gamma rays with an irradiation dose of 15 kGy to ensure that the pipe material reaches a certain sterility level. .

[0029] A composite medical interventional tubing with alternating soft and hard segments includes a tubing body. The tubing body has an alternating soft and hard segment composite structure along the axial direction. The soft segments and hard segments are connected by chemical bonding. The glass transition temperature of the soft segments is -40℃, the glass transition temperature of the hard segments is 50℃, the outer diameter of the tubing is 0.5mm, and the wall thickness is 0.05mm.

[0030] Example 2: A composite medical interventional tubing with alternating soft and hard segments and its preparation method, comprising the following steps: Step S1: Preparation of soft segment prepolymer: Polyether diol with a number average molecular weight of 1000 and diisocyanate are mixed at a molar ratio of 1:1.125 and catalytically reacted at 75°C for 2.5 h under nitrogen protection to obtain a soft segment prepolymer with terminal -NCO groups. Step S2: Preparation of hard segment prepolymer: A chain extender with a number average molecular weight of 300 is mixed with diisocyanate at a molar ratio of 1:2.5 and catalytically reacted at 85°C for 1.5 h under nitrogen protection to obtain a hard segment prepolymer with terminal -NCO groups. Step S3: Alternating copolymerization reaction. The soft segment prepolymer and the hard segment prepolymer are alternately added to the co-rotating twin-screw reactive extruder at a mass ratio of 1:1. The barrel temperature is controlled at 140℃-190℃ and the screw speed is 40rpm. The tube blank with alternating soft and hard segment structure is formed by in-situ polymerization. Step S4: Post-processing and shaping. The tube blank is subjected to gradient cooling, plasma surface grafting modification and aseptic packaging in sequence to obtain the soft and hard segment alternating composite medical interventional tubing.

[0031] In step S1, the polyether diol is a combination of polytetrahydrofuran ether diol and polypropylene oxide diol, the diisocyanate is a combination of hexamethylene diisocyanate and isophorone diisocyanate, and the catalyst used in the catalytic reaction is dibutyltin dilaurate, with an addition amount of 0.03% of the total mass of the reaction system.

[0032] In step S2, the chain extender is a combination of 1,6-hexanediol and diethyl terephthalate, and the catalyst used for the catalytic reaction is stannous octoate, with an addition amount of 0.05% of the total mass of the reaction system.

[0033] In step S3, the co-rotating twin-screw reactive extruder is divided into a preheating section, a mixing section, a reaction section, and an extrusion section along the material flow direction. The temperature of the preheating section is 145℃, the temperature of the mixing section is 165℃, the temperature of the reaction section is 180℃, and the temperature of the extrusion section is 185℃. The interval between the alternating addition of soft segment prepolymer and hard segment prepolymer is 7.5 min. The strong chemical bonding of the two-phase interface is achieved through the shearing action of the twin screw.

[0034] In step S4, gradient cooling adopts a three-stage temperature control: the first stage cooling temperature is 125℃, the second stage cooling temperature is 85℃, and the third stage cooling temperature is 30℃. The cooling time for each stage is 12.5 min, and the cooling medium is an aqueous solution of ethylene glycol.

[0035] Step S4, plasma surface grafting modification, is carried out in a vacuum reaction chamber, specifically as follows: Place the tube blank in the chamber and evacuate until... A mixture of argon and acrylic acid monomers is introduced, with a volume ratio of argon to acrylic acid of 4:1. An RF plasma generator is used, with a power of 200W and a processing time of 7.5 minutes, to introduce carboxyl functional groups onto the surface of the pipe.

[0036] In step S3, during the in-situ polymerization process, 1.0% of the total mass of the reaction system of nano-reinforcing filler is added. The nano-reinforcing filler is a combination of nano-hydroxyapatite and carbon nanotubes with a particle size of 30 nm. After surface modification with silane coupling agent KH-570, it is dispersed in the hard segment prepolymer.

[0037] In both steps S1 and S2, the catalytic reaction was accompanied by ultrasonic-assisted dispersion. The ultrasonic frequency was 50 kHz, the power was 300 W, and the dispersion time was 25 min, which promoted the full contact between the isocyanate groups and the hydroxyl groups.

[0038] Before aseptic packaging in step S4, an irradiation sterilization step is also included, using electron beam irradiation with an irradiation dose of 20 kGy to ensure that the pipe material reaches a certain sterility level. .

[0039] A composite medical interventional tubing with alternating soft and hard segments includes a tubing body. The tubing body has an alternating soft and hard segment composite structure along the axial direction. The soft segments and hard segments are connected by chemical bonding. The glass transition temperature of the soft segments is -30℃, the glass transition temperature of the hard segments is 65℃, the outer diameter of the tubing is 5.25mm, and the wall thickness is 0.275mm.

[0040] Example 3: A composite medical interventional tubing with alternating soft and hard segments and its preparation method, comprising the following steps: Step S1: Preparation of soft segment prepolymer: Polyether diol with a number average molecular weight of 1200 and diisocyanate are mixed at a molar ratio of 1:1.2 and catalytically reacted at 80°C for 3 hours under nitrogen protection to obtain a soft segment prepolymer with terminal -NCO groups. Step S2: Preparation of hard segment prepolymer: A chain extender with a number average molecular weight of 400 is mixed with diisocyanate at a molar ratio of 1:3 and catalytically reacted at 90°C for 2 hours under nitrogen protection to obtain a hard segment prepolymer with terminal -NCO groups. Step S3: Alternating copolymerization reaction. The soft segment prepolymer and hard segment prepolymer are alternately added to the co-rotating twin-screw reactive extruder at a mass ratio of 1:1.2. The barrel temperature is controlled at 140℃-190℃ and the screw speed is 50rpm. The tube blank with alternating soft and hard segment structure is formed by in-situ polymerization. Step S4: Post-processing and shaping. The tube blank is subjected to gradient cooling, plasma surface grafting modification and aseptic packaging in sequence to obtain the soft and hard segment alternating composite medical interventional tubing.

[0041] In step S1, the polyether diol is a combination of polytetrahydrofuran ether diol and polypropylene oxide diol, the diisocyanate is a combination of 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate, and the catalyst used in the catalytic reaction is dibutyltin dilaurate, with an addition amount of 0.05% of the total mass of the reaction system.

[0042] In step S2, the chain extender is a combination of 1,4-butanediol, 1,6-hexanediol and diethyl terephthalate, and the catalyst used for the catalytic reaction is stannous octoate, with an addition amount of 0.08% of the total mass of the reaction system.

[0043] In step S3, the co-rotating twin-screw reactive extruder is divided into a preheating section, a mixing section, a reaction section, and an extrusion section along the material flow direction. The temperature of the preheating section is 150℃, the temperature of the mixing section is 170℃, the temperature of the reaction section is 185℃, and the temperature of the extrusion section is 190℃. The interval between the alternating addition of soft segment prepolymer and hard segment prepolymer is 10 min. The shearing action of the twin screw achieves a strong chemical bond at the interface of the two phases.

[0044] In step S4, gradient cooling adopts a three-stage temperature control: the first stage cooling temperature is 130℃, the second stage cooling temperature is 90℃, and the third stage cooling temperature is 35℃. The cooling time for each stage is 15 minutes, and the cooling medium is deionized water.

[0045] Step S4, plasma surface grafting modification, is carried out in a vacuum reaction chamber, specifically as follows: Place the tube blank in the chamber and evacuate until... A mixture of argon and acrylic acid monomers is introduced, with a volume ratio of argon to acrylic acid of 5:1. An RF plasma generator is used, with a power of 300W and a processing time of 10 minutes, to introduce carboxyl functional groups onto the surface of the pipe.

[0046] In step S3, during the in-situ polymerization process, 1.5% of the total mass of the reaction system of nano-reinforcing filler is added. The nano-reinforcing filler is a combination of nano-silica, nano-hydroxyapatite and carbon nanotubes with a particle size of 50 nm. After surface modification with silane coupling agent KH-570, it is dispersed in the hard segment prepolymer.

[0047] In both steps S1 and S2, the catalytic reaction was accompanied by ultrasonic-assisted dispersion. The ultrasonic frequency was 60 kHz, the power was 400 W, and the dispersion time was 30 min, which promoted the full contact between the isocyanate groups and the hydroxyl groups.

[0048] Before aseptic packaging in step S4, an irradiation sterilization step is also included, using gamma rays with an irradiation dose of 25 kGy to ensure that the pipe material reaches a certain sterility level. .

[0049] A composite medical interventional tubing with alternating soft and hard segments includes a tubing body. The tubing body has an alternating soft and hard segment composite structure along the axial direction. The soft segments and hard segments are connected by chemical bonding. The glass transition temperature of the soft segments is -20℃, the glass transition temperature of the hard segments is 80℃, the outer diameter of the tubing is 10mm, and the wall thickness is 0.5mm.

[0050] Comparative Example 1 differs from Example 1 in that: in the alternating copolymerization reaction, the soft segment prepolymer and hard segment prepolymer were not added alternately, but the two were premixed and copolymerized. Comparative Example 2 differs from Example 2 in that: this comparative example does not use a gradient cooling process in the post-processing and shaping, but directly uses natural cooling to room temperature; Comparative Example 3 differs from Example 3 in that: in the plasma surface grafting modification step, no carboxyl functional groups were introduced in this comparative example, and only conventional argon plasma cleaning was performed. Comparative Example 4 differs from Example 3 in that ultrasonic-assisted dispersion was not used in the preparation of the soft segment prepolymer and the hard segment prepolymer in this comparative example.

[0051] The performance of the soft-hard segment alternating composite medical interventional tubing and its preparation method in Examples 1-3 and Comparative Examples 1-4 were tested. The test items and test methods are as follows: Interfacial bonding stability test: Through dynamic mechanical and thermal analysis, the glass transition region between soft and hard segments is observed to evaluate the continuity of interfacial chemical bonding. Dimensional accuracy testing: An optical image measuring instrument is used to measure the deviation of the outer diameter and wall thickness of the pipe after cooling, and to evaluate the uniformity of residual stress release; Surface modification uniformity test: X-ray photoelectron spectroscopy is used to scan the distribution of functional groups at different locations on the pipe surface to evaluate the chemical consistency of the grafted layer. Structural integrity test: The axial cross-sectional morphology of the pipe is observed by scanning electron microscopy to verify the regularity of the alternating soft and hard sections composite structure.

[0052] The test data of the alternating soft and hard segment composite medical interventional tubing and its preparation method in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below:

[0053] By comparing and analyzing the data in the table, it can be seen that the soft-hard segment alternating composite medical interventional tubing and its preparation method in Examples 1-3 have superior performance compared to the soft-hard segment alternating composite medical interventional tubing and its preparation method in Comparative Examples 1-4. This indicates that in the preparation of the soft-hard segment alternating composite medical interventional tubing, by presetting the alternating addition sequence of the soft segment prepolymer and the hard segment prepolymer and the segmented temperature control parameters of the co-rotating twin-screw reactive extruder, the uniform dispersion and full reaction of the soft and hard segments during the in-situ polymerization process can be ensured. Real-time monitoring of the bonding state of the two-phase interface can be achieved, avoiding interface bonding defects caused by deviations in the timing of alternating addition or uneven mixing, thus ensuring the stability of the axial soft-hard segment alternating composite structure of the tubing. This achieves the alternating soft-hard segment composite structure along the axial direction of the tubing wall. During the post-processing and shaping of the tubing blank, by executing gradient... The cooling process monitors the temperature fluctuations of the cooling medium in each section in real time, dynamically adjusting the cooling rate to match the stress release process inside the pipe. It can detect temperature anomalies during the cooling process in real time, allowing the system to correct cooling parameters in time before the pipe warps or dimensional deviations occur, reducing the risk of structural deformation caused by residual stress concentration and ensuring the dimensional accuracy of the pipe's outer diameter and wall thickness. When performing plasma surface grafting modification on the pipe, the system dynamically adjusts the proportion of gas components and radio frequency power parameters in the reaction chamber, and monitors the introduction density and distribution of surface functional groups in real time. It can adjust the treatment intensity according to the real-time response of the pipe surface, avoiding differences in modification effect caused by parameter fluctuations, making the chemical structure of the grafted layer on the pipe surface more uniform, and improving the pipe's subsequent processing adaptability and interface bonding reliability.

[0054] By comparing and analyzing the relevant data in the table, it can be seen that the soft and hard segment alternating composite medical interventional tubing and its preparation method of the present invention have superior comprehensive performance.

[0055] 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.

[0056] 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 composite medical interventional tubing with alternating soft and hard segments, characterized in that, Includes the following steps: Step S1: Preparation of soft segment prepolymer: Polyether diol with a number average molecular weight of 800-1200 is mixed with diisocyanate at a molar ratio of 1:1.05-1:1.2 and catalytically reacted at 70℃-80℃ for 2-3 hours under nitrogen protection to obtain a soft segment prepolymer with terminal -NCO groups. Step S2: Preparation of hard segment prepolymer: A chain extender with a number average molecular weight of 200-400 is mixed with diisocyanate at a molar ratio of 1:2-1:3 and catalytically reacted at 80℃-90℃ for 1-2 hours under nitrogen protection to obtain a hard segment prepolymer with terminal -NCO groups. Step S3: Alternating copolymerization reaction. Soft segment prepolymer and hard segment prepolymer are alternately added to a co-rotating twin-screw reactive extruder at a mass ratio of 1:0.8-1:1.

2. The barrel temperature is controlled at 140℃-190℃ and the screw speed is 30rpm-50rpm. In-situ polymerization is used to form a tube blank with an alternating soft and hard segment structure. Step S4: Post-processing and shaping. The tube blank is subjected to gradient cooling, plasma surface grafting modification and aseptic packaging in sequence to obtain the soft and hard segment alternating composite medical interventional tubing.

2. The method for preparing a composite medical interventional tubing with alternating soft and hard segments according to claim 1, characterized in that, In step S1, the polyether diol is selected from one or a combination of two of polytetrahydrofuran ether diol and polypropylene oxide diol, and the diisocyanate is selected from one or a combination of 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. The catalyst used in the catalytic reaction is dibutyltin dilaurate, and the amount added is 0.01%-0.05% of the total mass of the reaction system.

3. The method for preparing a composite medical interventional tubing with alternating soft and hard segments according to claim 1, characterized in that, The chain extender mentioned in step S2 is selected from one or more combinations of 1,4-butanediol, 1,6-hexanediol, and diethyl terephthalate. The catalyst used for the catalytic reaction is stannous octoate, and the amount added is 0.02%-0.08% of the total mass of the reaction system.

4. The method for preparing a composite medical interventional tubing with alternating soft and hard segments according to claim 1, characterized in that, The co-rotating twin-screw reactive extruder described in step S3 is divided into a preheating section, a mixing section, a reaction section, and an extrusion section along the material flow direction. The temperature of the preheating section is 140℃-150℃, the temperature of the mixing section is 160℃-170℃, the temperature of the reaction section is 175℃-185℃, and the temperature of the extrusion section is 180℃-190℃. The interval between the alternating addition of soft segment prepolymer and hard segment prepolymer is 5min-10min. The strong chemical bonding of the two-phase interface is achieved through the shearing action of the twin screw.

5. The method for preparing a composite medical interventional tubing with alternating soft and hard segments according to claim 1, characterized in that, The gradient cooling described in step S4 adopts a three-stage temperature control: the first stage cooling temperature is 120℃-130℃, the second stage cooling temperature is 80℃-90℃, and the third stage cooling temperature is 25℃-35℃. The cooling time for each stage is 10min-15min, and the cooling medium is deionized water or ethylene glycol aqueous solution.

6. The method for preparing a composite medical interventional tubing with alternating soft and hard segments according to claim 1, characterized in that, The plasma surface grafting modification described in step S4 is carried out in a vacuum reaction chamber, specifically as follows: Place the tube blank in the chamber and evacuate to 5×10⁻⁶. -2 Pa-5×10 -3 Pa, a mixture of argon and acrylic acid monomer is introduced, wherein the volume ratio of argon to acrylic acid is 3:1-5:

1. A radio frequency plasma generator is used, with a power set to 100W-300W and a processing time of 5min-10min, to introduce carboxyl functional groups on the surface of the pipe.

7. The method for preparing a composite medical interventional tubing with alternating soft and hard segments according to claim 1, characterized in that, In the in-situ polymerization process described in step S3, 0.5%-1.5% of nano-reinforcing filler is added to the total mass of the reaction system. The nano-reinforcing filler is selected from one or more combinations of nano-silica, nano-hydroxyapatite, and carbon nanotubes, with a particle size of 10nm-50nm. After surface modification with silane coupling agent KH-570, it is dispersed in the hard segment prepolymer.

8. The method for preparing a composite medical interventional tubing with alternating soft and hard segments according to claim 1, characterized in that, The catalytic reactions described in steps S1 and S2 are accompanied by ultrasonic-assisted dispersion. The ultrasonic frequency is 40kHz-60kHz, the power is 200W-400W, and the dispersion time is 20min-30min, which promotes the full contact between the isocyanate groups and the hydroxyl groups.

9. The method for preparing a composite medical interventional tubing with alternating soft and hard segments according to claim 1, characterized in that, Before aseptic packaging as described in step S4, an irradiation sterilization step is also included, using gamma rays or electron beam irradiation at a dose of 15kGy-25kGy to ensure that the pipe material reaches a sterility level of 10. -6 .

10. A composite medical interventional tubing with alternating soft and hard segments, prepared by the method described in any one of claims 1 to 9, characterized in that, A composite medical interventional tubing with alternating soft and hard segments includes a tubing body. The tubing body has an axial structure with alternating soft and hard segments. The soft segments and hard segments are connected by chemical bonding. The glass transition temperature of the soft segments is -40℃ to -20℃, and the glass transition temperature of the hard segments is 50℃ to 80℃. The outer diameter of the tubing is 0.5mm to 10mm, and the wall thickness is 0.05mm to 0.5mm.

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