A porous ultrasound imaging catheter with smooth surface and its preparation and application

Abstract

The present application provides a porous ultrasound imaging catheter with a smooth surface and its preparation and application, comprising the following steps: S1. After mixing a first thermoplastic resin, ammonium nitrate and reinforcing fiber, heating and melting at 185-230°C, extruding and forming, and then cooling and solidifying to obtain a porous inner tube catheter; S2. After mixing a second thermoplastic resin and a compatibilizer, melting at 90-180°C to obtain a liquid resin material, and coating the porous inner tube catheter with the liquid resin material to obtain a porous ultrasound imaging catheter with a smooth surface; the melting temperature of the first thermoplastic resin is ≥180°C; the present application simultaneously melts, extrude and produces gas with the first thermoplastic resin and ammonium nitrate in the same temperature range to obtain a porous inner tube catheter with pores inside and on the surface, and increases the acoustic impedance difference with the help of gas to improve the ultrasound imaging effect; and then the second thermoplastic resin is coated and embedded on the outside to improve the safety and durability of the ultrasound catheter.

Description

Technical Field

[0001] The invention relates to the field of medical materials, and in particular to a porous ultrasonic imaging catheter with a smooth surface and the preparation and application thereof. Background Art

[0002] Catheter products used in surgery are divided into two categories: developing and non-developing. The developing catheter can effectively help doctors track and determine the location of the catheter during surgery; drainage catheters and other interventional catheters involved in minimally invasive interventional treatments require the use of electronic equipment such as X-ray machines, CT, and ultrasound for guidance.

[0003] Since the acoustic impedance of existing medical interventional catheter materials is similar to that of human soft tissue (1.52×106kg / m 2 s) is close, making the ultrasound image of the existing interventional catheter in the human body blurred. Therefore, researchers have adopted different methods to enhance the ultrasonic reflection coefficient of the interventional catheter and thus improve the clarity of the ultrasound image of the interventional catheter in the human body. For example, the surface of the imaging catheter is roughened to enhance the sound wave scattering and reflection ability of the material surface and improve the ultrasound imaging effect. The roughening method includes surface engraving and modification with laser technology after the catheter is extruded. Although it can improve the ultrasound imaging effect to a certain extent, it acts on the surface with poor effect, destroys the smoothness of the product surface, increases the friction with the blood vessels during movement in the body, and easily damages the blood vessels; for example, a coating that can improve the ultrasound imaging effect is added, but the coating has the risk of falling off, poor safety, and low biosafety.

[0004] Therefore, it is necessary to provide an ultrasound imaging catheter with good ultrasound imaging effect and small biological loss. Summary of the invention

[0005] In view of the defects in the prior art, the present invention proposes a porous ultrasound imaging catheter with a smooth surface and its preparation and application, so as to solve the problem of how to improve the imaging effect of the ultrasound imaging catheter and reduce the damage to the organism.

[0006] The present application provides a method for preparing a porous ultrasound imaging catheter with a smooth surface, comprising the following steps:

[0007] S1. The first thermoplastic resin, ammonium nitrate, and reinforcing fiber are mixed, heated to melt at 185-230°C, extruded, and then cooled and solidified to obtain a porous inner tube conduit;

[0008] S2. The second thermoplastic resin and the compatibilizer are mixed and melted at 90-180°C to obtain a liquid resin material, and the porous inner tube catheter is coated with the liquid resin material to obtain a porous ultrasound imaging catheter having a smooth surface;

[0009] The melting temperature of the first thermoplastic resin is ≥180°C.

[0010] Preferably, in step S1, the first thermoplastic resin includes one or more of polystyrene, polycarbonate, and polyurethane.

[0011] Preferably, in step S1, the reinforcing fibers include one or more of carbon fibers and basalt fibers.

[0012] Preferably, in step S2, the second thermoplastic resin includes one or more of polymethyl methacrylate, polyvinyl chloride, and polyethylene.

[0013] Preferably, in step S2, the compatibilizer includes one or more of PE-G-MAH, EAA, SPEEK, and PS-G-MAH.

[0014] Preferably, in step S2, the coating process is to take out after coating and / or dipping, and then cool and solidify.

[0015] Preferably, the amount of ammonium nitrate used is 2-5% of the first thermoplastic resin.

[0016] Preferably, the ratio of the amount of ammonium nitrate to the amount of reinforcing fiber is (2-5):2.

[0017] In a second aspect, the present application provides a porous ultrasound imaging catheter with a smooth surface.

[0018] In a third aspect, the present application provides an application of a porous ultrasound imaging catheter with a smooth surface in medical materials.

[0019] In summary, compared with the prior art, the present invention achieves the following technical effects: the present application simultaneously melt-extrudes and produces gas with a first thermoplastic resin and ammonium nitrate in the same temperature range to obtain a porous inner tube catheter with pores inside and on the surface, and increases the difference in acoustic impedance with the help of gas to improve the ultrasonic imaging effect; then, the second thermoplastic resin is coated on the outside to make the second thermoplastic resin and the porous inner tube catheter interlock with each other, thereby improving the bonding force and avoiding the separation of the first thermoplastic resin and the porous inner tube catheter, with high stability and durability, and the coated second thermoplastic resin makes the outer surface of the ultrasonic imaging catheter smooth, will not damage blood vessels, and has high safety. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0021] A method for preparing a porous ultrasound imaging catheter with a smooth surface comprises the following steps:

[0022] S1. The first thermoplastic resin, ammonium nitrate, and reinforcing fiber are mixed, heated to melt at 185-230°C, extruded, and then cooled and solidified to obtain a porous inner tube conduit;

[0023] S2. The second thermoplastic resin and the compatibilizer are mixed and melted at 90-180°C to obtain a liquid resin material, and the porous inner tube catheter is coated with the liquid resin material to obtain a porous ultrasound imaging catheter having a smooth surface;

[0024] The melting temperature of the first thermoplastic resin is ≥180°C.

[0025] In the present application, step S1 is to melt-extrude the first thermoplastic resin at the decomposition temperature of ammonium nitrate to obtain a porous inner tube catheter; since ammonium nitrate will decompose at 185-230°C to produce non-toxic gases (nitrous oxide, nitrogen, oxygen, water vapor), and the first thermoplastic resin can be melted at 185-230°C, the two materials are melt-extruded and gas-generated at the same temperature range, and excess water is evaporated to obtain a porous inner tube catheter with pores inside and on the surface, thereby improving the development effect of the ultrasonic catheter; it is worth noting that if the heating temperature is lower than 185°C, it is difficult for ammonium nitrate to produce gas and the product is highly irritating, and it is difficult to form a large number of pores during the melt extrusion process, especially to form pores on the outer wall of the inner tube catheter. If it is higher than 230°C, the decomposition of ammonium nitrate is too violent and dangerous.

[0026] In step S2, the second thermoplastic resin is melted and coated on the porous inner tube catheter, so that the porous ultrasound imaging catheter has a smooth outer surface, which reduces the friction between the ultrasound imaging catheter and the blood vessels when it moves in the body, thereby avoiding blood vessel damage; at the same time, since there are certain pores on the outer surface of the porous inner tube catheter, the fluid second thermoplastic resin can achieve mutual embedding of the first thermoplastic resin and the second thermoplastic resin after coating the porous inner tube catheter, and with the help of the compatibilizer, they are more tightly combined, thereby avoiding the inner and outer layers of the ultrasound imaging catheter from separating from each other after long-term use, thereby improving the stability of the ultrasound imaging catheter.

[0027] At the same time, in order to prevent the first thermoplastic resin from softening or melting during coating with the second thermoplastic resin and causing pore collapse, the melting temperature of the first thermoplastic resin is ≥180° C., that is, not lower than the heating melting temperature of step S2 .

[0028] In some embodiments, the first thermoplastic resin includes one or more of polystyrene, polycarbonate, and polyurethane; when the melting temperature of the first thermoplastic resin is 180-230°C, the first thermoplastic resin melts while the ammonium nitrate is thermally decomposed and gasified. For example, when polystyrene (melting point 212°C) with a CAS number of 9003-53-6 is used as the first thermoplastic resin, the heating and melting temperature of step S1 is set to 212-230°C, preferably, the heating and melting temperature is set to 212°C; when polycarbonate (melting point 220-230°C) with a CAS number of 25037-45-0 is used as the first thermoplastic resin, the heating and melting temperature of step S1 is set to 220-230°C, preferably, the heating and melting temperature is set to 230°C.

[0029] In some embodiments, the second thermoplastic resin includes one or more of polymethyl methacrylate (CAS 9011-14-7, melting point 150°C), polyvinyl chloride (CAS 9002-86-2, melting point 170°C), and polyethylene (CAS 9002-88-4, melting point 92°C), which can be melted at low temperature and cover the porous inner tube conduit.

[0030] In some embodiments, the reinforcing fibers include one or more of carbon fibers and basalt fibers; the reinforcing fibers have good compatibility with thermoplastic resins and can improve the strength and toughness of the ultrasound imaging catheter to improve durability.

[0031] In some embodiments, the coating method is: taking out after coating and / or dipping, and then cooling and curing; so that the second thermoplastic resin can evenly coat the porous inner layer conduit.

[0032] In some embodiments, the compatibilizer includes one or more of PE-G-MAH, EAA, SPEEK, and PS-G-MAH; the compatibilizer is beneficial to improving the compatibility and bonding strength between the second thermoplastic resin and the first thermoplastic resin, and avoiding separation of the two after curing.

[0033] In some embodiments, the amount of ammonium nitrate used is 2-5% of the first thermoplastic resin; in some embodiments, the ratio of the amount of ammonium nitrate used to the amount of reinforcing fiber used is (2-5):2; an increase in the amount of ammonium nitrate used can increase the pores inside and / or on the surface of the porous inner tube catheter, but too many pores will lead to a decrease in the strength and toughness of the ultrasonic imaging catheter, so it is necessary to increase the reinforcing fiber to improve the strength and toughness of the ultrasonic imaging catheter.

[0034] The present application provides a porous ultrasound imaging catheter with a smooth surface.

[0035] The present application provides an application of a porous ultrasound imaging catheter with a smooth surface in medical materials.

[0036] The present solution is further described below through specific implementation methods.

[0037] Example 1

[0038] A method for preparing a porous ultrasound imaging catheter with a smooth surface comprises the following steps:

[0039] S1. 100g polystyrene (CAS 9003-53-6), 2g ammonium nitrate and 2g carbon fiber are mixed and placed in an internal mixer, heated to 215°C for melting, melt blended for 20 minutes, and extruded to form a porous inner tube with an extrusion diameter of 3mm, and then cooled and solidified to obtain a porous inner tube;

[0040] S2. Mix 100g of polyethylene (CAS 9002-88-4) and 2g of PE-G-MAH, and melt them at 100°C to obtain a liquid resin material. Immerse the porous inner tube catheter in the liquid resin material for 2 minutes. After taking it out and cooling and solidifying, recycle the immersion (2 minutes) and cooling and solidifying treatments for 2 more times to obtain a porous ultrasound imaging catheter with a smooth surface.

[0041] Example 2

[0042] A method for preparing a porous ultrasound imaging catheter with a smooth surface comprises the following steps:

[0043] S1. 100g polystyrene (CAS 9003-53-6), 5g ammonium nitrate and 2g carbon fiber are mixed and placed in an internal mixer, heated to 215°C for melting, melt blended for 20 minutes, and extruded to form a porous inner tube with an extrusion diameter of 3mm, and then cooled and solidified to obtain a porous inner tube;

[0044] S2. Mix 100g of polyethylene (CAS 9002-88-4) and 2g of PE-G-MAH, and melt them at 100°C to obtain a liquid resin material. Immerse the porous inner tube catheter in the liquid resin material for 2 minutes. After taking it out and cooling and solidifying, recycle the immersion (2 minutes) - cooling and solidification treatment for 2 more times to obtain a porous ultrasound imaging catheter with a smooth surface.

[0045] Example 3

[0046] A method for preparing a porous ultrasound imaging catheter with a smooth surface comprises the following steps:

[0047] S1. 100g of polystyrene (CAS 9003-53-6), 10g of ammonium nitrate and 3g of carbon fiber were mixed and placed in an internal mixer, heated to 215°C for melting, melt blended for 20 minutes, and extruded to form a porous inner tube with an extrusion diameter of 3mm, and then cooled and solidified to obtain a porous inner tube;

[0048] S2. Mix 100g of polyethylene (CAS 9002-88-4) and 2g of PE-G-MAH, and melt them at 100°C to obtain a liquid resin material. Immerse the porous inner tube catheter in the liquid resin material for 2 minutes. After taking it out and cooling and solidifying, recycle the immersion (2 minutes) - cooling and solidification treatment for 2 more times to obtain a porous ultrasound imaging catheter with a smooth surface.

[0049] Example 4

[0050] A method for preparing a porous ultrasound imaging catheter with a smooth surface comprises the following steps:

[0051] S1. 100g polycarbonate (CAS 25037-45-0), 1g ammonium nitrate and 3g carbon fiber were mixed and placed in an internal mixer, heated to 230°C for melting, melt blended for 15 minutes, and extruded to form a porous inner tube with an extrusion diameter of 3mm, and then cooled and solidified to obtain a porous inner tube;

[0052] S2. Mix 100g of polymethyl methacrylate (CAS 9011-14-7) and 5g of PE-G-MAH, and melt them at 150°C to obtain a liquid resin material. Immerse the porous inner tube catheter in the liquid resin material for 2 minutes. After taking it out and cooling and solidifying, recycle the immersion (2 minutes) - cooling and solidification treatment for 2 more times to obtain a porous ultrasound imaging catheter with a smooth surface.

[0053] Comparative Example 1

[0054] A method for preparing an ultrasound imaging catheter comprises the following steps:

[0055] S1. 100g of polyvinyl chloride (CAS 9002-86-2), 2g of ammonium nitrate and 2g of carbon fiber were mixed, placed in an internal mixer, heated to 170°C for melting, melt blended for 20 minutes, and extruded to form an extrusion with an extrusion diameter of 3mm, and then cooled and solidified to obtain an inner tube catheter;

[0056] S2. Mix 100g of polyethylene (CAS 9002-88-4) and 2g of PE-G-MAH, and melt them at 100°C to obtain a liquid resin material. Immerse the inner tube catheter in the liquid resin material for 2 minutes. After taking it out and cooling and solidifying, recycle the immersion (2 minutes), cool and solidify it twice, and then obtain an ultrasound imaging catheter.

[0057] Comparative Example 2

[0058] A method for preparing an ultrasound imaging catheter comprises the following steps:

[0059] S1. 100g of polystyrene (CAS 9003-53-6) and 2g of carbon fiber were mixed, placed in an internal mixer, heated to 215°C for melting, melt blended for 20 minutes, and extruded to form an extrusion with an extrusion diameter of 3mm, and then cooled and solidified to obtain an inner tube catheter;

[0060] S2. Mix 100g of polyethylene (CAS 9002-88-4) and 2g of PE-G-MAH, and melt them at 100°C to obtain a liquid resin material. Immerse the inner tube catheter in the liquid resin material for 2 minutes. After taking it out and cooling and solidifying, recycle the immersion (2 minutes), cool and solidify it twice, and then obtain an ultrasound imaging catheter.

[0061] Comparative Example 3

[0062] A method for preparing an ultrasound imaging catheter comprises the following steps:

[0063] S1. 100g of polystyrene (CAS 9003-53-6) and 2g of ammonium nitrate were mixed, placed in an internal mixer, heated to 215°C for melting, melt blended for 20 minutes, and extruded to form an extrusion with an extrusion diameter of 3mm, and then cooled and solidified to obtain an inner tube catheter;

[0064] S2. Mix 100g of polyethylene (CAS 9002-88-4) and 2g of PE-G-MAH, and melt them at 100°C to obtain a liquid resin material. Immerse the inner tube catheter in the liquid resin material for 2 minutes. After taking it out and cooling and solidifying, recycle the immersion (2 minutes), cool and solidify it twice, and then obtain an ultrasound imaging catheter.

[0065] Comparative Example 4

[0066] A method for preparing an ultrasound imaging catheter comprises the following steps:

[0067] 100g polystyrene (CAS 9003-53-6), 2g ammonium nitrate and 2g carbon fiber are mixed, placed in an internal mixer, heated to 215°C for melting, melt blended for 20 minutes, and extruded, wherein the extrusion diameter is 3mm, and then cooled and solidified to obtain a porous inner tube catheter, that is, a porous ultrasonic imaging catheter with a smooth surface.

[0068] Test and Evaluation

[0069] The ultrasonic imaging catheters obtained in the embodiments and comparative examples were tested for ultrasonic effect, mechanical properties and surface morphology.

[0070] Among them, the test method of ultrasound effect is: taking the grayscale of ultrasound image simulating tissue vascular wall as the benchmark, the ultrasound imaging effects of different samples can be compared by comparing the ratio of the b peak area (Sb, representing the brightness of the sample ultrasound image, that is, the light spot density) to the a peak area (Sa, representing the brightness of the blood vessel wall ultrasound image) of different samples. The larger the ratio, the better the development effect of the spline ultrasound image. The results are shown in Table 1.

[0071] The test standards for mechanical properties are: toughness is tested according to GB / T 1451-2005 "Test method for simply supported beam impact toughness of fiber reinforced plastics"; tensile strength is tested according to GB / T 16421-1996 "Test method for small specimens of plastic tensile properties"; the results are shown in Table 1.

[0072] Table 1 Performance test results of different ultrasound catheters

[0073]

[0074] As can be seen from Table 1, the amount of ammonium nitrate in Examples 1-4 increases successively, and the pore volume of the obtained ultrasonic imaging material increases and the surface is smooth, but the Sb / Sa value is: Example 2> Example 1> Example 3> Example 4, which shows that although the increase of ammonium nitrate is beneficial to improving the development effect of the ultrasonic imaging material, excessive use of ammonium nitrate will also bring disadvantages. The reason may be that when the amount of ammonium nitrate is too much, the reaction is more intense during melt extrusion, resulting in bubbles overflowing from the inner tube catheter, which in turn reduces the pore volume of the inner tube catheter. At the same time, its toughness and tensile strength show that Example 2<Example 1<Example 3<Example 4, which shows that the larger the pore volume, the worse the mechanical properties. , the comprehensive performance of Example 1 is better; compared with Example 1, Comparative Example 1 replaces the type of the first thermoplastic resin and heats and melts it at 170°C, resulting in insufficient decomposition of ammonium nitrate, so the pore volume is sharply reduced, the Sb / Sa value is greatly reduced, and the mechanical properties do not change much; Comparative Example 2 does not use ammonium nitrate, the Sb / Sa value is greatly reduced, and the mechanical properties do not change much; Comparative Example 3 does not use carbon fiber, the mechanical properties are greatly reduced, but the Sb / Sa value does not change much; Comparative Example 4 does not use the second thermoplastic resin, and the surface of the obtained ultrasonic imaging material is not smooth, which is easy to cause damage to the body, and the imaging effect and mechanical properties are also negatively affected.

[0075] The present application simultaneously melt-extrudes and produces gas through a first thermoplastic resin and ammonium nitrate in the same temperature range, thereby obtaining a porous inner tube catheter having pores inside and on the surface, and using the gas to increase the acoustic impedance difference and improve the ultrasonic imaging effect; and then coating the outside with a second thermoplastic resin so that the second thermoplastic resin and the porous inner tube catheter are interlocked with each other to improve the bonding force and avoid separation of the first thermoplastic resin and the porous inner tube catheter, with high stability and durability, and the coated second thermoplastic resin makes the outer surface of the ultrasonic imaging catheter smooth, does not damage blood vessels, and has high safety.

[0076] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a porous ultrasound imaging catheter with a smooth surface, characterized in that: The following steps are involved: S1. The first thermoplastic resin, ammonium nitrate, and reinforcing fiber are mixed, heated to melt at 185-230°C, extruded, and then cooled and solidified to obtain a porous inner tube conduit; S2. The second thermoplastic resin and the compatibilizer are mixed and melted at 90-180°C to obtain a liquid resin material, and the porous inner tube catheter is coated with the liquid resin material to obtain the porous ultrasound imaging catheter having a smooth surface; The melting temperature of the first thermoplastic resin is ≥180°C; in step S1, the first thermoplastic resin includes one or more of polystyrene and polycarbonate; the reinforcing fiber includes one or more of carbon fiber and basalt fiber; in step S2, the second thermoplastic resin includes one or more of polymethyl methacrylate and polyethylene; in step S2, the compatibilizer includes one or more of PE-G-MAH, EAA, SPEEK, and PS-G-MAH.

2. The method for preparing a porous ultrasound imaging catheter with a smooth surface according to claim 1, characterized in that: In step S2, the coating process is to take out after coating and / or dipping, and then cool down and solidify.

3. The method for preparing a porous ultrasound imaging catheter with a smooth surface according to claim 1, characterized in that: The amount of ammonium nitrate used is 2-5% of the first thermoplastic resin.

4. The method for preparing a porous ultrasound imaging catheter with a smooth surface according to claim 1, characterized in that: The ratio of the amount of ammonium nitrate to the amount of reinforcing fiber is (2-5):

2.

5. A porous ultrasound imaging catheter with a smooth surface prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the porous ultrasound imaging catheter with a smooth surface as claimed in claim 5 in the preparation of medical materials.

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