Polymer braided heart valve and preparation method thereof

Abstract

The present invention provides a polymer braided heart valve and a preparation method thereof. The polymer braided heart valve is formed by a braiding process, including an upper fabric layer with a corrugated structure, a flat lower fabric layer and an expanded polytetrafluoroethylene yarn in the middle. The upper fabric layer and the lower fabric layer are fabrics woven from core-shell composite yarns; the core layer of the core-shell composite yarn is a high-elasticity, high-strength core wire, and the outer layer is a polytetrafluoroethylene filament. The present invention coats the polytetrafluoroethylene filament on the surface of the high-elasticity, high-strength core wire, and obtains a core-shell composite yarn for constructing a polymer braided valve by regulating the filament and spinning process parameters, and cooperates with the braiding process to obtain a polymer braided heart valve with upper and lower layers of core-shell composite yarn fabric layers and an expanded polytetrafluoroethylene yarn in the middle; the valve has good structural stability, high strength, elasticity, biocompatibility, and excellent anti-fouling ability, anti-coagulation ability, and the function of reducing immune response, and has good application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of bionic valve materials, and in particular to a polymer braided heart valve and a preparation method thereof. Background Art

[0002] For valvular heart disease, the best treatment is to replace the diseased valve with an artificial heart valve. Currently, artificial heart valves used for valve replacement can be divided into mechanical valves and biological valves. Mechanical valves are durable, but they are accompanied by side effects such as hemodynamic changes and thrombosis. Patients need to take anticoagulants for life to avoid thrombosis problems; however, long-term use of anticoagulants may cause difficulty in stopping bleeding, gastrointestinal reactions, negative emotions, allergies and other side effects, reducing people's quality of life. Biological valves made by cross-linking pig or bovine pericardium with glutaraldehyde have good biocompatibility. At the same time, the blood flow of the biological valve through the valve orifice is central flow, without obstruction, and can form a blood flow form close to that of physiology. The tissue treated with glutaraldehyde has the advantages of high strength and low immunogenicity. However, the calcium ions in the calcium-containing extracellular fluid react and combine with the phosphate-rich substances in the cell membrane to form nuclei and aggregate, making the biological valve tissue hard and fragile, resulting in loss of valve function, forming calcium phosphate deposits, and then calcification. At the same time, platelets, fibrinogen and cellular components in the blood aggregate and retain in the leaflet part of the valve to form local thrombi and cause embolism. Severe thrombotic events can even directly cause death.

[0003] The invention patent (publication number CN 106535824 A) discloses a method for manufacturing an artificial valve and a valve obtained by the method, and proposes a double-layer woven cloth with ultra-high molecular weight polyethylene (UHMWPE) as longitudinal and transverse tubular filling fibers as a valve leaf. The invention patent (publication number CN 108904877A) discloses an interventional artificial heart valve based on a polymer fiber composite material and a preparation method thereof, with a polymer fiber cloth as the main body and a composite polymer valve coated with polyethylene glycol gel on the surface. However, the above polymer valve material may deform and adhere under long-term curling conditions, and cannot quickly restore the original shape when used; at the same time, the above polymer valve material lacks anti-fouling ability, and platelets and fibrinogen in the blood and cell components are prone to aggregation and retention in the leaf-shaped part of the valve to form thrombi, reducing its mechanical strength. In addition, the above fiber-reinforced valve cannot simulate the stress conditions of the natural valve well, and its strength and durability are still not ideal.

[0004] In view of this, it is necessary to design an improved polymer braided heart valve and a preparation method thereof to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a polymer braided heart valve and a preparation method thereof, wherein a high-elasticity, high-strength core wire is used as a core layer, and a surface layer is wrapped with polytetrafluoroethylene filaments to obtain a core-shell composite yarn for constructing a polymer braided valve, and a braiding molding process is used to obtain a polymer braided heart valve with upper and lower layers being core-shell composite yarn fabric layers and a middle layer being expanded polytetrafluoroethylene yarn; the valve has good structural stability, high strength, high elasticity, biocompatibility, as well as anti-fouling ability, anti-coagulation ability and the function of reducing immune response.

[0006] To achieve the above-mentioned purpose of the invention, the present invention provides a polymer braided heart valve, which is formed by a weaving process and includes an upper fabric layer with a corrugated structure, a flat lower fabric layer and an expanded polytetrafluoroethylene yarn in the middle. The upper fabric layer and the lower fabric layer are both fabrics woven from core-shell composite yarns; the core layer of the core-shell composite yarn is a high-elasticity, high-strength core wire, and the outer layer is a polytetrafluoroethylene filament.

[0007] As a further improvement of the present invention, the core-shell composite yarn is the polytetrafluoroethylene filament composited on the surface of the high-elasticity and high-strength core wire by uniformly wrapping it.

[0008] As a further improvement of the present invention, the breaking strength of the high-elasticity and high-strength core wire is 10-20 MPa, and the breaking elongation is 600%-700%.

[0009] As a further improvement of the present invention, the fineness of the high-elasticity and high-strength core wire is 140-280D, and the fineness of the polytetrafluoroethylene filament is 50-100D.

[0010] As a further improvement of the present invention, the expanded polytetrafluoroethylene yarn is a yarn with a rectangular cross-section, a thickness of 0.1 to 0.2 mm, and a width of 0.1 to 0.5 mm.

[0011] As a further improvement of the present invention, the high-elasticity and high-strength core yarn includes one or more of polyurethane, polypropylene, and PET fiber filaments.

[0012] The present invention also provides a method for preparing any one of the above-mentioned polymer braided heart valves, comprising the following steps:

[0013] S1. Prepare core-shell composite yarn; uniformly wrap polytetrafluoroethylene filaments on the surface of high-elasticity and high-strength core wires to obtain core-shell composite yarns; the coverage rate of the outer polytetrafluoroethylene filaments of the core-shell composite yarn on the inner core wires is 90% to 95%;

[0014] S2. The core-shell composite yarn of step S1 is woven or knitted into a double-layer fabric, and during the weaving process, the expanded polytetrafluoroethylene yarn is woven into the middle of the double-layer fabric by a weft insertion process to obtain a polymer braided heart valve in which the upper and lower layers are core-shell composite yarn fabric layers and the middle layer is expanded polytetrafluoroethylene yarn.

[0015] As a further improvement of the present invention, in step S2, weaving is performed in a shuttle weaving manner, including the following steps: (1) the core-shell composite yarn is used as the warp yarn to perform the weaving preparation process of drawing in the heald and reed, and the drawn-in warp yarn is adjusted to an appropriate tension before the weaving process; (2) the core-shell composite yarn is used as the weft yarn to perform plain weave weaving of a preset length; (3) weaving is performed according to the weft-insertion structure, the weaving cycle is 8 pages of heald frames, and a number of weaving cycles are first woven to form a weft-insertion structure of a certain warp length, and then the inner and outer layered pattern is called to separate the upper warp yarn from the lower warp yarn, and the expanded polytetrafluoroethylene yarn is filled in as the weft yarn of the weft-insertion structure, and finally, the plain weave is continued to be called for sealing; (4) the process of step (3) is repeated to continue weaving until the polymer braided heart valve of a certain size is obtained.

[0016] As a further improvement of the present invention, in step S2, weaving is performed by knitting, including the following steps: (1) adjusting the tension of the core-shell composite yarn, feeding it under the needle plate, and fixing it; (2) starting the needle, presetting the fabric width, first adding the core-shell composite yarn to the machine head, hanging the needle comb, and hanging the weight; (3) performing double needle plate operation, first weaving a rib structure, and on this basis, inserting a number of non-looped expanded polytetrafluoroethylene yarns along the weft direction, and then weaving the rib structure; (4) repeating the process of step (3) in subsequent weaving until the polymer braided heart valve of a certain size is obtained.

[0017] As a further improvement of the present invention, in step S1, the specific preparation process of the core-shell composite yarn is to adopt S-twist and Z-twist synergistic yarn-making process to evenly wrap the polytetrafluoroethylene filaments on the surface of the high-elasticity and high-strength core wire.

[0018] The beneficial effects of the present invention are:

[0019] 1. The polymer braided heart valve of the present invention is formed by a weaving process, including an upper fabric layer with a corrugated structure, a flat lower fabric layer and an expanded polytetrafluoroethylene yarn in the middle. The upper fabric layer and the lower fabric layer are fabrics woven from core-shell composite yarns; the core layer of the core-shell composite yarn is a high-elasticity, high-strength core wire, and the outer layer is a polytetrafluoroethylene filament. The present invention uses a high-elasticity, high-strength core wire as the core layer, and wraps the surface layer with polytetrafluoroethylene filaments to obtain a core-shell composite yarn for constructing a polymer braided valve, and cooperates with the weaving molding process to obtain a polymer braided heart valve with upper and lower layers of core-shell composite yarn fabric layers and an expanded polytetrafluoroethylene yarn in the middle; the valve has good structural stability, high strength, high elasticity, biocompatibility, and excellent anti-fouling ability, anti-coagulation ability and immune response reduction function; it solves the problem that various defects of existing polymer valve materials exist in practical applications, and has good application prospects.

[0020] 2. The present invention obtains a core-shell composite yarn with a high-elasticity and high-strength core yarn as the core layer and a polytetrafluoroethylene filament covered on the surface by regulating the filament and spinning process parameters. The outer layer of the polymer braided valve constructed by the core-shell composite yarn in contact with the blood is a hydrophobic polytetrafluoroethylene material with extremely strong anti-fouling properties. The formed surface hydrophobic structure has long-term stability in the blood environment in the body, can effectively reduce the formation of thrombus and calcification spots, has good blood compatibility, and prolongs the service life of the valve; and the high-elasticity and high-strength core yarn in the core-shell composite yarn improves the structural stability and elasticity of the braided valve, reduces its deformation and adhesion under long-term curling conditions, and the braided valve can easily restore its original shape after deformation, and has strong applicability.

[0021] 3. The polymer braided heart valve of the present invention adopts an integrated braiding molding process, which can mimic the physiological structure of natural valves. The upper and lower fabrics woven from the core-shell composite yarns have different structures. By biomimetic natural leaflet fiber layer and ventricular layer structure, the polymer braided valve stent has different properties in radial and circumferential directions, thereby improving the strength and durability of the polymer valve. The expanded polytetrafluoroethylene yarn filled in the braiding process constructs a bionic natural leaflet sponge layer structure, replicating the buffering function after blood flow reflux during valve closure. In addition, the unique corrugated structure formed by the polymer braided heart valve during the braiding process also provides partial tension requirements along the radial direction (perpendicular to the leaflet edge), effectively alleviating the aging problem of the composite yarn and extending the service life of the polymer braided heart valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the polymer braided heart valve of the present invention.

[0023] Figure 2It is a schematic diagram of the core-shell composite yarn structure obtained by the S-twist and Z-twist collaborative yarn-forming process of the present invention.

[0024] Reference numerals

[0025] 100-polymer braided heart valve; 110-upper fabric; 120-lower fabric; 130-core-shell composite yarn; 131-polytetrafluoroethylene filament; 132-high elasticity and high strength core wire; 140-expanded polytetrafluoroethylene yarn. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0028] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0029] See also Figure 1-2 As shown, a polymer braided heart valve 100 is formed by a weaving process, and includes an upper fabric layer 110 with a corrugated structure, a flat lower fabric layer 120 and an expanded polytetrafluoroethylene yarn 140 in the middle. The upper fabric layer 110 and the lower fabric layer 120 are both fabrics woven from core-shell composite yarns 130; the core layer of the core-shell composite yarn 130 is a high-elasticity, high-strength core wire 132, and the outer layer is a polytetrafluoroethylene filament 131. The present invention uses a high-elasticity and high-strength core wire 132 as the core layer, and wraps the surface layer with polytetrafluoroethylene filaments 131 to obtain a core-shell composite yarn 130 for constructing a polymer braided heart valve 100, and cooperates with a braiding molding process to obtain a polymer braided heart valve 100 with upper and lower layers being core-shell composite yarn 130 fabric layers and the middle being expanded polytetrafluoroethylene yarn 140; the valve has good structural stability, high strength, high elasticity, biocompatibility, and excellent anti-fouling ability, anti-coagulation ability and the function of reducing immune response.

[0030] Specifically, the core-shell composite yarn 130 is a polytetrafluoroethylene filament 131 that is evenly wrapped and composited on the surface of a high elasticity and high strength core wire 132. The breaking strength of the high elasticity and high strength core wire 132 is 10-20Mpa, and the breaking elongation is 600%-700%. The fineness of the high elasticity and high strength core wire 132 is 140-280D, and the fineness of the polytetrafluoroethylene filament 131 is 50-100D. The expanded polytetrafluoroethylene yarn 140 is a yarn with a rectangular cross-section, and its thickness is 0.1-0.2mm and its width is 0.1-0.5mm.

[0031] In some specific embodiments, the expanded polytetrafluoroethylene yarn 140 is made by cutting and splitting a plate-like expanded polytetrafluoroethylene material; when used in a braided valve, the expanded polytetrafluoroethylene yarn 140 is a yarn bundle composed of one or more yarns.

[0032] The outer layer of the polymer braided heart valve 100 constructed with core-shell composite yarn 130 that contacts the blood is a hydrophobic, highly anti-fouling polytetrafluoroethylene material. The formed surface hydrophobic structure has long-term stability in the blood environment in the body, can effectively reduce the formation of thrombi and calcification spots, has good blood compatibility, and extends the service life of the valve; and the high-elasticity, high-strength core wire 132 in the core-shell composite yarn 130 improves the structural stability and elasticity of the braided valve, reduces its deformation and adhesion under long-term curling conditions, and the braided valve can easily restore its original shape after deformation, and has strong applicability.

[0033] In some specific embodiments, the high-elasticity and high-strength core yarn includes one or more of polyurethane, polypropylene, and PET fiber filaments.

[0034] It should be noted that, in practical applications, the polymer braided heart valve 100 prepared by the present invention is used as a leaflet material; the upper fabric layer 110 of the polymer braided heart valve 100 with a corrugated structure is used as the inner layer of the leaflet, and the flat lower fabric layer 120 is used as the outer layer, so that the leaflet has better opening and closing performance and hemodynamics. Those skilled in the art should know that the flat lower fabric layer 120 is a corrugated structure relative to the upper fabric layer 110, and presents a flat structure at the macro level; but since the lower fabric layer 120 is also woven and formed by the core-shell composite yarn 130, it has a yarn woven structure at the micro level.

[0035] The present invention also provides a method for preparing a polymer braided heart valve 100, comprising the following steps:

[0036] S1. Prepare core-shell composite yarn 130; evenly wrap polytetrafluoroethylene filaments 131 on the surface of high elasticity and high strength core wire 132 to obtain core-shell composite yarn 130; the coverage rate of outer polytetrafluoroethylene filaments 131 on inner core wire of core-shell composite yarn 130 is 90% to 95%; through this process, the polytetrafluoroethylene filaments 131 are repeatedly wrapped around the core layer high elasticity and high strength core wire 132 to achieve the effect of complete coverage without core leakage;

[0037] S2. The core-shell composite yarn 130 of step S1 is woven or knitted into a double-layer fabric, and during the weaving process, the expanded polytetrafluoroethylene yarn 140 is woven into the middle of the double-layer fabric by a weft insertion process, so as to obtain a polymer braided heart valve 100 in which the upper and lower layers are core-shell composite yarn 130 fabric layers and the middle layer is expanded polytetrafluoroethylene yarn 140; because of the intervention of the middle expanded polytetrafluoroethylene yarn 140, a corrugated structure is formed on the surface of the upper fabric layer 110 of the material in conjunction with the weaving process, and the corrugated structure can play a buffering role in practical applications, improve the mechanical properties of the valve, and also make the material have better opening and closing performance and hemodynamics when applied to the leaflets.

[0038] The present invention obtains a core layer of a high-elasticity, high-strength core filament 132 and a core-shell composite yarn 130 coated with polytetrafluoroethylene filaments 131 on the surface by regulating the filament and spinning process parameters. The integrated weaving molding process can be used to mimic the physiological structure of a natural valve. The core-shell composite yarn 130 cooperates with the expanded polytetrafluoroethylene yarn 140 to weave upper and lower fabrics with different structures. By mimicking the natural leaflet fiber layer and ventricular layer structure, the polymer braided valve stent has different properties in radial and circumferential directions, thereby improving the strength and durability of the polymer valve. The expanded polytetrafluoroethylene yarn 140 filled in the weaving process constructs a bionic natural leaflet sponge layer structure, replicating the buffering function after blood flow reflux during valve closure. In addition, the unique corrugated structure formed by the polymer braided heart valve 100 during the weaving process also provides a partial tension requirement along the radial direction (perpendicular to the leaflet edge), effectively alleviating the aging problem of the composite yarn and extending the service life of the polymer braided heart valve 100.

[0039] Specifically, in step S2, weaving is performed in a shuttle weaving manner, including the following steps: (1) using the core-shell composite yarn as the warp yarn to perform the weaving preparation process of threading and reeding, and adjusting the tension of the threaded warp yarn to an appropriate level before performing the weaving process; (2) using the core-shell composite yarn as the weft yarn to perform plain weave weaving of a preset length; (3) weaving according to the weft-insertion structure, the weaving cycle is 8 pages of heald frames, first weaving a number of weaving cycles to form a weft-insertion structure of a certain warp length, then calling the inner and outer layered pattern to separate the upper warp yarn from the lower warp yarn, filling in expanded polytetrafluoroethylene yarn as the weft yarn of the weft-insertion structure, and finally, continuing to call the plain weave for sealing; (4) repeating the process of step (3) to continue weaving until a polymer braided heart valve of a certain size is obtained. Among them, the tension adjustment in step (1), the preset length in step (2), and the warp length of the weft-insertion structure in step (3) can all be flexibly adjusted according to actual needs.

[0040] The weaving is carried out in a knitting manner, and includes the following steps: (1) passing the core-shell composite yarn and the expanded polytetrafluoroethylene yarn through the yarn guide hook respectively, adjusting the tension, feeding under the needle plate, and fixing; (2) starting needles, presetting the fabric width, first adding the core-shell composite yarn to the machine head, hanging the needle comb, and hanging the weight; (3) working with a double needle plate, first weaving a rib structure, and on this basis inserting a number of non-looped expanded polytetrafluoroethylene yarns along the weft direction, and then weaving the rib structure; (4) repeating the process of step (3) in subsequent weaving until the polymer braided heart valve with a certain size is obtained. Among them, the fabric width in step (2) and the number of expanded polytetrafluoroethylene yarns in step (3) can be flexibly adjusted according to actual needs.

[0041] In some specific embodiments, in step S1, the specific preparation process of the core-shell composite yarn 130 is to use the S-twist and Z-twist synergistic yarn-forming process to evenly wrap the polytetrafluoroethylene filament 131 on the surface of the high-elasticity and high-strength core yarn 132. The specific operation method of the S-twist and Z-twist synergistic yarn-forming process is as follows:

[0042] A hollow spindle covering machine and two groups of hollow spindles are used to spin the core-shell composite yarn 130. The high elasticity and high strength core wire 132 is inserted along the upper and lower hollow spindles. The wrapping twist direction is configured to be the same direction or the reverse direction (cross). The lower spindle twist direction is selected as S twist, and the upper spindle is selected as S twist and Z twist respectively, so as to achieve bidirectional covering of the polytetrafluoroethylene filament 131 around the high elasticity and high strength core wire 132.

[0043] In practical applications, in order to improve the performance of the material, the braided material obtained in step S2 may be subjected to heat setting treatment before being used as a valve material.

[0044] Example 1

[0045] This embodiment provides a method for preparing a polymer braided heart valve 100, comprising the following steps:

[0046] S1. Prepare a core-shell composite yarn 130; uniformly wrap polytetrafluoroethylene filaments 131 on the surface of a polyurethane core yarn through an S-twist and a Z-twist synergistic yarn-forming process to obtain a core-shell composite yarn 130; wherein the coverage rate of the outer polytetrafluoroethylene filaments 131 of the core-shell composite yarn 130 on the inner core yarn is 92.5%; the breaking strength of the polyurethane core yarn is 17Mpa, the breaking elongation is 670%, the fineness is 200D, and the fineness of the polytetrafluoroethylene filaments 131 is 80D;

[0047] S2. The core-shell composite yarn 130 of step S1 is woven into a double-layer fabric by shuttle weaving, and during the weaving process, the expanded polytetrafluoroethylene yarn 140 is woven into the middle of the double-layer fabric by a weft insertion process, so as to obtain a polymer braided heart valve 100 in which the upper and lower layers are core-shell composite yarn 130 fabric layers and the middle layer is expanded polytetrafluoroethylene yarn 140; wherein the expanded polytetrafluoroethylene yarn 140 is a yarn with a rectangular cross-section, and its thickness is 0.1 mm and its width is 0.2 mm.

[0048] Example 2

[0049] This embodiment provides a method for preparing a polymer braided heart valve 100. Compared with Embodiment 1, the difference lies in that, in step S2, a double-layer fabric is woven by knitting. The rest is substantially the same as Embodiment 1 and will not be described again.

[0050] Comparative Example 1

[0051] Comparative Example 1 provides a method for preparing a heart valve. Compared with Example 1, the difference is that polyurethane fiber is used instead of the core-shell composite yarn 130 for weaving, and the rest is roughly the same as Example 1 and will not be repeated here.

[0052] Comparative Example 2

[0053] Comparative Example 2 provides a method for preparing a heart valve. Compared with Example 1, the difference is that polytetrafluoroethylene filaments are used instead of the core-shell composite yarn 130 for weaving, and the rest is roughly the same as Example 1 and will not be repeated here.

[0054] Comparative Example 3

[0055] Comparative Example 3 provides a method for preparing a heart valve. Compared with Example 1, the difference is that polyurethane fiber is used instead of the core-shell composite yarn 130 and the expanded polytetrafluoroethylene yarn 140 for weaving and forming, and then the upper and lower fabric surfaces of the obtained woven material are coated with polytetrafluoroethylene to obtain a heart valve material.

[0056] Comparative Example 4

[0057] Comparative Example 4 provides a method for preparing a heart valve. Compared with Example 1, the difference is that in step S2, the weaving of expanded polytetrafluoroethylene yarn 140 is not added, and the upper and lower layers are core-shell composite yarn 130 fabrics. The rest is roughly the same as Example 1 and will not be repeated here.

[0058] The heart valve materials prepared in Examples 1 to 2 and Comparative Examples 1 to 4 were tested for relevant properties, such as mechanical properties, surface hydrophobicity (contact angle) or compliance, patency rate and calcification experiments; it was found that the braided heart valves prepared in Examples 1 and 2 had good elasticity and strength, strong structural stability and good biocompatibility; and the surface contact angle of the material was large, it was a hydrophobic structure, and it had strong anti-fouling properties, which could reduce the formation of thrombi and calcification spots. The pure polyurethane braided valve of Comparative Example 1, although it had good elasticity, was easy to activate the cascade reaction of blood coagulation, resulting in the occurrence of thrombi and calcification. The pure polytetrafluoroethylene valve material of Comparative Example 2 had poor mechanical properties and was difficult to meet the requirements of clinical applications. In the braided heart valve materials of Comparative Examples 3 and 4, although they had good biocompatibility and anti-fouling ability, they did not form a corrugated structure during the braiding process, and it was difficult to meet the opening and closing performance and tension requirements of the valve.

[0059] In summary, the present invention provides a polymer braided heart valve and a preparation method thereof, which is formed by a braiding process, including an upper fabric layer with a corrugated structure, a flat lower fabric layer and an expanded polytetrafluoroethylene yarn in the middle, and the upper fabric layer and the lower fabric layer are fabrics woven from core-shell composite yarns; the core layer of the core-shell composite yarn is a high-elasticity, high-strength core wire, and the outer layer is a polytetrafluoroethylene filament. The present invention uses a high-elasticity, high-strength core wire as the core layer, and the surface layer is wrapped with polytetrafluoroethylene filaments. By regulating the filaments and spinning process parameters, a core-shell composite yarn for constructing a polymer braided valve is obtained, and the braiding molding process is combined to obtain a polymer braided heart valve with upper and lower layers of core-shell composite yarn fabric layers and an expanded polytetrafluoroethylene yarn in the middle; the valve has good structural stability, high strength, high elasticity, biocompatibility, excellent anti-fouling ability, anti-coagulation ability and the function of reducing immune response, and also has good application prospects.

[0060] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A polymer braided heart valve, characterized in that: The polymer braided heart valve is formed by a braiding process, and includes an upper fabric layer with a corrugated structure, a flat lower fabric layer and an expanded polytetrafluoroethylene yarn in the middle, wherein the upper fabric layer and the lower fabric layer are fabrics woven from core-shell composite yarns; the core layer of the core-shell composite yarn is a high-elasticity, high-strength core wire, and the outer layer is a polytetrafluoroethylene filament; the core-shell composite yarn is the polytetrafluoroethylene filament compounded on the surface of the high-elasticity, high-strength core wire by uniformly wrapping; the high-elasticity, high-strength core wire includes one or more of polyurethane, polypropylene, and PET fiber filaments; the expanded polytetrafluoroethylene yarn is a yarn with a rectangular cross-section, and its thickness is 0.1-0.2 mm and its width is 0.1-0.5 mm; The method for preparing the polymer braided heart valve comprises the following steps: S1. Prepare core-shell composite yarn; uniformly wrap polytetrafluoroethylene filaments on the surface of high-elasticity and high-strength core wires to obtain core-shell composite yarns; the coverage rate of the outer polytetrafluoroethylene filaments of the core-shell composite yarn on the inner core wires is 90% to 95%; S2, weaving the core-shell composite yarn of step S1 into a double-layer fabric by woven or knitted method, and weaving the expanded polytetrafluoroethylene yarn in the middle of the double-layer fabric by weft insertion process during the weaving process, so as to obtain a polymer braided heart valve with the upper and lower layers being core-shell composite yarn fabric layers and the middle layer being expanded polytetrafluoroethylene yarn; In step S2, weaving is performed in a shuttle weaving manner, including the following steps: (1) the core-shell composite yarn is used as the warp yarn to perform the weaving preparation process of drawing in the heald and reeding, and the drawn-in warp yarn is adjusted to an appropriate tension before the weaving process is performed; (2) the core-shell composite yarn is used as the weft yarn to perform plain weave weaving of a preset length; (3) weaving is performed according to the weft insertion structure, the weaving cycle is 8 pages of heald frames, and a number of weaving cycles are firstly woven to form a weft insertion structure of a certain warp length, and then the inner and outer layered pattern is called to separate the upper warp yarn from the lower warp yarn, and the expanded polytetrafluoroethylene yarn is filled in as the weft yarn of the weft insertion structure, and finally, the plain weave is continued to be called for sealing; (4) the process of step (3) is repeated to continue weaving until the polymer braided heart valve of a certain size is obtained; The weaving is carried out in a knitting manner, comprising the following steps: (1) passing the core-shell composite yarn through a yarn guide hook, adjusting the tension, feeding it under a needle plate, and fixing it; (2) starting the needle, presetting the fabric width, first adding the core-shell composite yarn to the machine head, hanging a needle starting comb, and hanging a heavy hammer; (3) performing double needle plate operation, first weaving a rib structure, and then inserting a plurality of non-looped expanded polytetrafluoroethylene yarns along the weft direction, and then weaving the rib structure; (4) repeating the process of step (3) in subsequent weaving until the polymer braided heart valve of a certain size is obtained.

2. The polymer braided heart valve according to claim 1, characterized in that: The breaking strength of the high-elasticity and high-strength core wire is 10-20 Mpa, and the breaking elongation is 600%-700%.

3. The polymer braided heart valve according to claim 1, characterized in that: The fineness of the high-elasticity and high-strength core wire is 140-280 D, and the fineness of the polytetrafluoroethylene filament is 50-100 D.

4. The polymer braided heart valve according to claim 1, characterized in that: In step S1, the specific preparation process of the core-shell composite yarn is to use S-twist and Z-twist synergistic yarn-making process to evenly wrap the polytetrafluoroethylene filaments on the surface of the high-elasticity and high-strength core yarn.

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