KR100770671B1 - Method of polymer trileaflet heart valve manufacturing using vacuum forming process - Google Patents

Abstract

A method for mechanically manufacturing a polymer trileaflet heart valve is provided to manufacture the polymer trileaflet heart valve having uniform characteristics and qualities. A method for mechanically manufacturing a polymer trileaflet heart valve includes the steps of: heating a polymer sheet and applying it to a leaflet mold by vacuum forming to obtain an artificial leaflet; assembling a leaflet shaped upper mold on the opposite side, while fixing the artificial leaflet to the leaflet mold; and applying a high-temperature polymer sheet to the upper mold by vacuum forming to obtain a valve conduit. Thusly manufactured artificial polymer valve conduit is constituted of a lower portion(30), a leaflet(20), and an upper portion(10).

Description

Method of manufacturing artificial heart valve using vacuum molding method {Method of polymer trileaflet heart valve manufacturing using vacuum forming process}

1 is a side view (a), a plan view (b), and a bottom view (c) of an artificial heart valve.

Figure 2 is a photograph of the vacuum molded valve leaf.

3 is a photograph (a) of vacuum forming the valve leaf in the vacuum molding machine and a photograph (b) of the valve leaf mold fixed to the pedestal. In the area indicated by the arrow there is a suction hole for vacuum forming.

4 shows the structure of a polymer artificial valve vacuum forming mold. (a) shows the structure of the entire assembled mold, (b) is an assembled picture of the valve leaf mold and the core mold, (c) is a pedestal for fixing the assembled valve leaf mold to the vacuum molding machine, (d ) Is a combined photograph of the assembled valve leaf mold, the core mold and the pedestal.

Figures 5a, b, c, d, e, f shows the mold removal process after vacuum molding of the valve conduit.

6 is a conceptual diagram of a manufacturing process of the artificial heart valve using vacuum molding.

The present invention relates to a method for producing a polymeric artificial heart valve using a vacuum molding method, and more specifically, after manufacturing an artificial valve leaf using a vacuum molding method, a high temperature polymer plate in a state in which a molded valve leaf is fixed to the valve leaf mold. It relates to a polymeric artificial heart valve manufacturing method for producing a valve conduit by secondary vacuum molding.

Artificial heart valves are used to replace surgical valves in the event that a human heart valve is damaged or functionally defective. It is also used to prevent the backflow of blood in the recently developed artificial heart or ventricular assist device.

Artificial heart valves can be divided into mechanical valves, tissue valves, and polymer valves depending on the composition of the main material.The mechanical valves prevent the reverse flow of blood by restricting the movement of circular or semi-circular hinges in one direction in the annular frame. The tissue valve is made of a heart valve or pericardium surrounding the heart in a structure similar to that of the aortic valve of the heart. The polymer valve may be used by molding a medical polymer into a form similar to the aortic valve, or may be manufactured in a structure that serves as a one-way check valve.

The structure of the aortic valve has three membranes with a flexible structure that prevents blood backflow, thereby preventing blood backflow. This is called a trilobal valve, and conventional tissue valves and polymer valves are mainly manufactured similarly to this type. Leaflets of artificial heart valves are similar to those of living heart valves, and durability is an important material selection criterion because they have to function in the body for a long time. In addition, since it is in direct contact with blood, it is necessary to select a material with good blood compatibility or use a material having added blood compatibility.

The manufacture of conventional trileaflet polymer valves has two steps. First, the parts corresponding to the valve leaf are first manufactured. This process produces a mold similar to the leaflet (leaflet), immersed in a polymer solution, and then repeated to dry the process to separate the polymer film from the mold to produce a leaflet shape. Next, the method is completed by bonding three valve leaves inside the valve conduit surrounding the manufactured valve leaves. At this time, the valve conduit is advantageous to form a sinus for each valve leaf to minimize the stagnant area of blood when the valve is closed, and the thickness is 2 to 20 times that of the valve leaf in consideration of the aortic thickness in vivo. It may be thick enough and have sufficient strength in vivo.

The process of manufacturing a conventional trileaflet polymer valve as described above has undergone a process of separately manufacturing and adhering the valve conduit injected with the polymer in a solution state or molded in another way, the production takes more than a few days, It is difficult to expect a uniform quality because the immersion and bonding process is performed by hand, and the productivity is not high, so it has low practicality.

Accordingly, the present inventors have made diligent efforts to overcome the problems of the prior arts. As a result, when the artificial heart valve is manufactured using the vacuum molding method, standardization and quality uniformity which are difficult to achieve in the conventional manual manufacturing method can be achieved. By combining the valve leaf and the valve conduit using heat expansion and contraction due to temperature difference, safety can be increased by not using solvent at the source, and the productivity is much higher because it can be manufactured mechanically in a relatively short time. The present invention was completed.

Accordingly, a main object of the present invention is to provide a method for producing a trileaf polymer artificial heart valve having uniform properties and quality by using a vacuum molding method.

The present invention, in the manufacture of a trifocal artificial heart valve, a lot of time in the process of manufacturing the leaflet (leaflet) by conventional immersion method, and the bonding process of the valve conduit (valve conduit) produced by injection molding, etc. This paper proposes a method to solve the problem that the quality difference is large depending on the proficiency when it is required and manual assembly or joining.

An object of the present invention is to apply a vacuum forming method having a shape of a mold by heating a polymer sheet having a thin plate shape near a melting point and then placing it on a mold to apply a vacuum forming method having a shape of a mold, and to manually manufacture the leaflet-valve conduit bonding process. In order to minimize this, it is possible to produce a trileaf polymer artificial heart valve with uniform characteristics and quality in a short time.

According to one aspect of the present invention, the present invention provides a method for producing a polymeric artificial heart valve, wherein after manufacturing the artificial valve leaf using the vacuum molding method, the high temperature polymer plate in a state in which the molded valve leaf is fixed to the valve leaf mold again It provides a polymeric artificial heart valve manufacturing method that induces binding to the valve leaf at the same time to produce a valve conduit by vacuum forming.

In the manufacturing method of the artificial artificial heart valve of the present invention, the production of artificial valve leaf is to process the valve leaf mold having a valve leaf shape of the outer peripheral surface and fixed in a vacuum molding machine, and then heated the polymer sheet to cover the valve leaf mold and then the valve leaf mold It is preferable that the polymer artificial heart valve manufacturing method is characterized by inducing a deformation of the polymer thin plate by applying a vacuum in the space between the polymer thin plate and the shape of the valve leaf. Figure 3a is a photograph of vacuum forming the valve leaf in the vacuum molding machine. As shown in Fig. 3a, a polymer sheet is placed on the valve leaf mold fixed to the vacuum molding machine, and the vacuum is applied by sucking air outward from the bottom of the vacuum molding machine. In the area indicated by the arrow there is an air suction hole for vacuum forming (Fig. 3a, b). In this case, polypropylene, polypropylene oxide, polyvinyl alcohol, polyurethane, polytetrafluoroethylene, or the like may be used as an example of the polymer. The optimum temperature of the polymer thin plate before molding is 160 ℃, the appropriate range is 120 ~ 180 ℃. In addition, the thickness of the polymer thin plate is appropriate 0.1 ~ 1 mm, the thickness range of the valve leaf is 0.1 ~ 0.5 mm is appropriate after molding. Since the vacuum molding is not molded to a uniform thickness, the preferred thickness after molding is 0.3 mm.

In the method for producing a polymeric artificial heart valve of the present invention, the production of the valve conduit is to put the molded valve leaf on the valve leaf mold, and assembling a valve-shaped intaglio mold (Upper mold) on the high temperature polymer plate After covering so as to cover the whole from the top of the intaglio mold, it is preferable to form a valve conduit by applying a vacuum to the space between the assembled mold and the polymer thin plate. Specifically, after the leaflet molding, only the parts necessary for the molded polymer leaflet are removed and the remaining portions are removed, and then assembled again to the leaflet mold, and the outer leaflets are assembled to form a valve conduit by combining three valve leaf molds. After placing the intaglio mold which becomes the intaglio intaglio on the upper part of the valve leaf mold, vacuum molding the polymer plate having a thickness of 0.5 to 6 mm in the above temperature range and then removing the valve leaf mold and the valve leaf intaglio mold on both sides. Have a process. The upper mold, which is placed on top of the three fixed leaflet molds, is not important for the inside of the vacuum mold, and the contact with the leaflet molds should be made at intervals of less than 0.1 mm.

Similar to the valve leaf mold molding method, which is a method of applying a vacuum between the polymer thin plate and the valve leaf mold of the present invention, the above-mentioned vacuum molding method is used for molding the valve conduit. In the shaping of the valve conduits, the vacuum forming machine used in the present invention has a pedestal with a hole connected to a vacuum pump at the bottom of the mold, thereby sucking the air therein. The base of the mold (FIG. 4C) has a frame on which a polymer plate (sheet) is mounted and a structure in which the mold is tightly sealed and sealed. In total, the polymer plate-frame-mould-supports are all in one space and vacuum is applied to the holes in the pedestal.

In the manufacturing method of the artificial artificial heart valve of the present invention, it is preferable that the manufacturing method comprises a trimming process of removing the remaining part with a cutter leaving only the necessary part of the molded polymer valve leaf after molding the valve leaf.

In the method for producing a polymeric artificial heart valve of the present invention, the valve leaf forming is performed by vacuum molding each of the three leaflet leaf molds one by one, and then fixing the formed leaflet leaf pieces to the assembled leaflet leaf mold. It is preferable that the method for producing a artificial artificial heart valve, characterized in that it comprises a method of vacuum forming the valve conduit. In other words, according to the present invention, the assembled valve leaf mold is fixed to a vacuum molding machine to cover the polymer thin plate, and the artificial leaflets are molded at one time and trimmed through the trimming process. As in the embodiment of the present invention, each valve leaf mold is covered with a polymer thin plate before assembling in one set to form three valve leaves, and then the valve leaf mold is assembled and fixed on it to form a valve conduit by artificial valve. It may also be prepared. Therefore, the artificial valve can be produced by any of the above two methods.

In the polymer artificial heart valve manufacturing method of the present invention, the vacuum forming process of the valve conduit is characterized in that the high temperature polymer plate is adhered to the valve leaf fixed to the mold by the expansion by heat and shrinkage by the temperature difference. When manufacturing the valve leaf in the vacuum molding process proposed in the present invention, the polymer thin plate becomes partially molten by high temperature (above the glass transition temperature, below the melting point), and easily deforms into the valve leaf mold shape and reaches the room temperature. Even if the lobe mold is removed, the deformation remains semipermanently. In addition, in the step of vacuum forming the valve conduit after assembling three valve leaves, the high temperature polymer plate is molded and the surface is stretched to bond with the valve leaf fixed to the mold. When it reaches room temperature, it remains bonded by a large force by residual stress.

In the polymer artificial heart valve manufacturing method of the present invention, after molding the artificial valve, a method for producing a polymeric artificial heart valve, characterized in that to improve the mechanical strength and durability by applying a polyurethane solution along the valve leaf-valve conduit border To provide. In the present invention, the vacuum-formed valve leaf and the valve conduit is strongly coupled, but the sharp portion of the valve leaf base where the two parts meet may be a fine gap. It is important to make this part round so that there is no gap in the blood. To this end, a polyurethane solution or a solution capable of dissolving the polyurethane along the boundary of the valve leaflet-valve conduit of the completed valve after vacuum molding is placed in a syringe and applied along the boundary line with a needle to fill a sharp gap. Even if the gap is not large, even 0.1 mm level can greatly affect the generation of blood clots, so when applied in this way, the gap is eliminated, and thus the clot formation is lost. In addition, the force acts between the valve conduit and the valve leaf due to the pressure difference between the inlet and outlet of the heart valve. When this gap is eliminated, the stress concentration point is reduced, thereby increasing durability.

According to another aspect of the present invention, a polymer artificial body including a valve leaf mold processed in the form of a valve leaf and a negative mold processed in the form of a leaf leaf in the form of a valve leaf using a vacuum molding method Provided is a mold for producing a heart valve.

In the mold for preparing a polymeric artificial heart valve of the present invention, the inner cross section of the valve leaf mold has a structure in which a cylinder is cut in a three-quad shape, and the valve leaf portion (the portion in contact with the conduit portion) is connected to the valve conduit. As the lobe mold, three valve lobe molds constitute one set of the valve lobe molds, and the curved part is formed in a portion in contact with the conduit part. That is, it is preferable to have a curved portion having an increased outer diameter so that the occurrence of the stagnant region is minimized hemodynamically after the preparation of the artificial artificial valve.

In the mold for preparing a polymeric artificial heart valve of the present invention, the structure of the valve leaf mold has a hollow core at the time of assembling the three leaf valve molds in order to effectively remove the valve leaf mold having the curved portion after vacuum molding, so as to remove the mold after molding. It is characterized by having an effective structure. Since the curved portion of the valve leaf mold is unfavorable for removal of the valve leaf mold after molding, the center of the assembled valve leaf mold is empty so that the valve leaf molds can be removed more easily while removing the three valve leaf molds one by one. (FIG. 5D, e, f).

In the mold for preparing the artificial heart valve according to the present invention, it is preferable to further include a core mold which assembles three valve leaf molds during valve conduit vacuum molding and fixes the lower portion to an empty center. Leaflet mold is a core (core) in the center in order to solve the problem that the bending portion (sinus) is protruding out after molding, and the core after the molding to remove the leaflet mold (Fig. 5a, b, c, d, e, f). Core mold functions to fix leaflet mold during molding. It also plays a role in facilitating removal of leaflet mold by first disassembling after molding.

The polymeric prosthetic valve prepared by the method of the present invention may be used for the purpose of preventing blood flow in one direction or to prevent backflow of blood. An example of application could be the valve of a pulsatile blood pump that has been widely used clinically and prosthetic valve replacement to improve heart valve failure.

The shape of the polymeric artificial valve produced by the method of the present invention has a characteristic portion of the valve conduit upper part 10, the valve leaf (curve) 10, and the valve conduit lower part 30, as shown in FIG. 1A. .

The vacuum molding method of the artificial artificial valve presented in the present invention can achieve the standardization and quality uniformity which are difficult to achieve by the conventional method of manufacturing the polymeric valve, and used a polymer solution dissolved in a solvent harmful to human body in the conventional process. The method proposed in the present invention has the advantage of increasing safety by not using a solvent at the source of the valve leaf-valve conduit due to thermal expansion and shrinkage due to temperature difference during the vacuum molding process.

Hereinafter, the present invention will be described in more detail with reference to Examples. Since these examples are only for illustrating the present invention, the scope of the present invention is not to be construed as being limited by these examples.

Example  One. Valve leaf Of mold  Produce

The inner cross section had a structure in which a cylinder was cut into a three-quadrant shape, and three valve leaves were assembled, and then curved parts were formed on the outside to process three valve leaf molds having an outer circumferential surface of the valve leaf (FIG. 3B). Then, the processed valve leaf molds were fixed in a vacuum molding machine for valve leaf molding.

Example  2. Valve leaf  Vacuum forming

The processed valve leaf mold was fixed to a vacuum molding machine, and a 0.1-1.0 mm polyurethane thin plate heated to 160 ° C. was placed on the valve leaf mold, followed by molding by applying a vacuum between the thin plate and the valve leaf mold (FIG. 3A). Three artificial valve leaflets formed in the form of valve leaflets were removed, leaving only the necessary portions (FIG. 2) (trimming, trimming).

Example  3. Valve conduit  Vacuum forming

Three artificial valve blades formed in Example 2 were placed on the valve leaf molds assembled and fixed in the valve leaf mold of Example 1, and then an upper mold was formed on the valve leaf molds. After vacuum molding by placing a polyurethane thin plate having a thickness of 0.5 ~ 6.0 mm heated to ℃, the valve leaf mold and the negative mold was removed from both sides.

Example  4. Completion of prosthetic valves

The valve lobe adheres firmly to the valve conduit during the molding of the valve conduit close to the melting point, and both sides of the molding are cut and trimmed to allow blood to pass therethrough, thereby removing the mold as shown in FIG. 5. Complete the form. In addition, polyurethane solution was applied to the interface of the valve leaf-valve conduit of the artificial valve completed in this process to increase durability.

As described above, according to the present invention, the conventional manufacturing method can be solved by one process of vacuum molding, as compared to the dipping process and injection molding, and there is no concern about side effects due to the remaining chemical solvent because the polymer solution is not used. Has the advantage that the source is blocked.

The present invention has the effect of simplifying the manufacturing process and providing a safer polymer valve without using an organic chemical solvent, while maintaining the functional characteristics of the existing polymer artificial heart valve as it is.

Claims (10)

Heating the polymer thin plate to cover the valve leaf mold and manufacturing an artificial valve leaf using a vacuum molding method; And assembling the valve leaf-shaped negative mold on the opposite side in the state where the molded valve leaf is fixed to the valve leaf mold, and covering the high temperature polymer plate on the negative mold and vacuum forming the valve leaf to manufacture the valve conduit. In the production of the valve leaf, the valve leaf mold having the shape of the valve leaf is fixed to the vacuum molding machine, and then the polymer thin plate is heated and covered with the valve leaf mold, and then vacuum is applied to the space between the valve leaf mold and the polymer leaf plate. And forming the leaf conduit on the valve leaf mold to assemble the leaf leaf mold on top of the leaf leaf mold and cover the high temperature polymer plate from the top of the leaf mold. After the cover is applied to the space between the assembled mold and the polymer thin plate to form a valve conduit characterized in that Polymeric artificial heart valve manufacturing method. delete delete The method of claim 1, further comprising a trimming process of removing the remaining portion with a cutter while leaving only the necessary portion of the molded polymer leaf after molding the valve leaf. The method of claim 1, wherein the valve leaf forming is performed by vacuum forming each of the three leaflet leaf molds one by one, and then fixing the formed leaflet leaves to the valve leaf mold assembled into one set. Polymeric artificial heart valve manufacturing method comprising a. The method of claim 1, wherein the vacuum forming process of the valve conduit is made by using a thermal expansion and contraction caused by a temperature difference to bond the hot polymer plate to the valve leaf fixed to the mold. The method of claim 1, wherein after the valve is formed, a polyurethane solution is applied along the valve leaf-valve conduit to improve mechanical strength and durability. The outer circumferential surface used for manufacturing the polymeric artificial heart valve using the vacuum molding method includes a valve leaf mold processed in the form of a valve leaf and an engraved mold processed in the form of a valve leaf shape, and the inner cross section of the valve leaf mold is a cylinder. It has a structure cut into a three-quadron shape, the valve leaf portion is connected to the valve conduit, the three molds are composed of a set of valve leaf mold, the polymer characterized in that to form a curved portion in contact with the conduit portion Mold for the manufacture of artificial heart valves. delete 9. The polymer artificial heart of claim 8, wherein the valve leaf mold has a structure in which a central portion of the valve leaf mold is substantially empty when the three valve leaf molds are assembled to effectively remove the valve leaf mold having the curved portion after vacuum forming. Mold for valve production.

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