JPH06297484A - Mold and manufacture of medical implement using the same - Google Patents

Abstract

PURPOSE:To simply mold in a stable quality by forming a mold of a dip molding of a hollow mold made of a film wall of a polymer material having a specific thickness or less. CONSTITUTION:A mold 1 is dipped in solution 2 in which polymer is dissolved, and then dried to remove solvent. In a dip molding for obtaining a molded form by forming a polymer film 5 and then removing the mold 1, a hollow mold made of a polymer material having a thickness or 2mm or less is used. Thus, since the mold 1 is deformable even if a mold drawing hole is smaller than the mold 1, volume is reduced by removing gas or liquid filled in the mold 1, the mold is wound or folded up in a paper string state to remove a molded form from the mold. Thus, the form can be removed from the mold 1 without deforming or expanding the form, thereby obtaining a stable molded form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dipping molding mold and a method for manufacturing a medical device, and more particularly to a molding method for obtaining a thin film molded article by a step of forming a film by dipping and then removing it from the mold. The present invention relates to a mold for manufacturing a medical device for molding a blood chamber part of a heart and a balloon part of an intra-aortic balloon pump, and a method for manufacturing a medical device using the mold.

[0002]

2. Description of the Related Art In recent years, an assisted artificial heart or intra-aortic balloon pumping has been frequently carried out as a mechanical assisting means to the heart for heart failure. For example, as shown in FIG. 1, the auxiliary artificial heart is a device in which a blood pump having a blood chamber is provided between the heart of the living body and the right atrium and the pulmonary artery or between the left atrium and the aorta in parallel with the heart of the living body to bypass the blood. Each of the blood chamber outlets and outlets has a check valve, and the whole chamber is compressed and expanded by a fluid, and the sack-type artificial heart that repeats inflow and outflow of blood and a part of the chamber are formed by a thin film called a diaphragm. Form and compress the diaphragm with fluid,
Diaphragm type artificial hearts that expand and infuse and pump blood have been developed and put into practical use. Because the artificial heart is used for a relatively long period of time and the anticoagulant for patients is limited to prevent postoperative bleeding, it is durable and antithrombogenic segmented polyether polyurethane or It is preferably molded from a segmented polyether type urethane urea or a copolymer of segmented polyurethane and polydimethylsiloxane.

The intra-aortic balloon pump inserts a narrow balloon of 20 to 40 cc into the aorta from the peripheral artery and places the balloon in the aorta. The drive device rapidly expands the balloon during the left ventricular diastole to increase the arterial pressure. It raises blood to the peripheral and coronary arteries, and immediately reduces the left ventricular ejection resistance by deflating the balloon that is inflating immediately before the left ventricular systole. This balloon is required to have antithrombogenicity and durability like the artificial heart, and is molded with segmented polyether type polyurethane, segmented polyether type urethane urea, or a copolymer of segmented polyurethane and polydimethylsiloxane. Is preferred.

As a method for molding the chambers and balloons of these blood pumps, the above polymeric materials are dissolved in an appropriate solvent to form a solution, and a mold is immersed in the solution and dried to remove the solvent. After that, the step of removing the coating formed on the mold surface and using it has been carried out.

However, this method is not a problem when the hole for taking out is larger than the required molded article, but when the hole for taking out is smaller than the molded article, the elongation of the polymer is utilized. It is necessary to forcibly remove it from the mold. When removing from the mold, a method of blowing air into the molded product to expand the coating film and removing the mold is frequently carried out.

[0006]

When the polymer is expanded and removed from the mold as described above, the important step is to remove it from the mold without deforming or damaging the molded thin film molded product. When the polymer is expanded to a certain extent or more, it deforms and returns to its original state, and a phenomenon occurs. Further, if the polymer is expanded more than the elongation at break, the film will be broken. Such a problem occurs when the hole for taking out the mold is smaller than the mold.

Several attempts have been reported as methods for solving such problems. JP-A-57-8
For 1350, a mold is prepared from wax that melts at a melting point of 120 to 130 ° C., the wax mold is dipped in a polyurethane solution to form a film, and then the mold is heated to a melting point or higher to melt it. A molding method for obtaining a cast film molded article is described. Further, in JP-A-61-225016, a mold is prepared from a water-soluble material that can be melted or dissolved, and after a polymer film is formed in the same manner, the mold is washed away by washing with water to form a film molded article. How to get is described. However, in the former method, the wax may be mixed in the molded product, and there is a problem in safety such as residual organic solvent used for washing the wax. Further, the method of producing a mold from a water-soluble material has problems that it is difficult to produce the mold itself, and the strength of the mold is weak and the work becomes difficult. The present invention relates to a method for forming an artificial heart, an intra-aortic balloon pump, or the like by dipping, and is made to solve the above problems.

[0008]

In order to solve the above-mentioned problems, according to the present invention, the mold is dipped in a solution in which a polymer is dissolved and then dried to remove the solvent to form a polymer film, and then the mold is formed. A hollow mold made of a polymer material having a thickness of 2 mm or less is used in the dipping molding for removing the mold to obtain a molded product. As a specific method, first, a mold having a desired shape is formed by blow molding. As a material for blow molding, a material which is usually used for blow molding such as polyethylene, polypropylene, acrylic resin, nylon and polystyrene can be used, but low density polyethylene is particularly preferable from the viewpoint of moldability and releasability. In the hollow volume variable mold of the present invention, the thickness of the membrane wall forming the hollow portion is preferably 2 mm or less. The production method is not particularly limited, and blow formation or the like is preferable.

A solution is prepared by dissolving a coating polymer in a solvent. For artificial hearts and intra-aortic balloon pumps, it is preferable to use segmented polyether type polyurethane, segmented polyether type urethane urea, and a copolymer of segmented polyurethane and polydimethylsiloxane.

As the solvent, the above polymer is dissolved,
Further, a material that does not melt the blow molding mold is preferably used. For example, when using the above materials for a mold of low density polyethylene, tetrahydrofuran or N.I. N-dimethylformamide and N.V. N-dimethylacetamide, dioxane and the like are preferably used. Usually, the polymer dope is prepared by dissolving in these solvents so as to be 1 to 35%.

Next, a blow molding mold is immersed in these solutions. A blow molding mold is filled with a gas or a liquid inside and then dipping, and the mold is pulled out of the liquid and dried to remove the solvent. This process is repeated until the desired film thickness is obtained, and a predetermined film thickness is obtained. When the solvent is sufficiently removed and the polymer film becomes tough, it is demolded.

When the blow-molded mold of the present invention is used, the mold itself can be deformed even when the die-cutting hole is smaller than the mold. Therefore, by removing the gas or liquid filling the mold, the volume is reduced, The molded product can be removed from the mold by winding it in a twist or folding it up. In this way, the molded product can be removed from the mold without being deformed or expanded, and a stable molded product can be obtained.

[0013]

Example 1 A method for manufacturing an IABP balloon using the present invention will be described below. A mold 1 as shown in FIG. 2 is manufactured by blow molding. A blow molding mold made of low density polyethylene is used. This mold is filled with silicone oil 3 for preventing deformation during the dipping process, and plugs 4 are closed at both ends. Next, a polymer solution is prepared. Polyether type polyurethane urea having tetramethylene glycol as a soft segment is used as a polymer, and N, N-dimethylformamide is used as a solvent. The polymer is dissolved in a solvent so that the concentration becomes 15% to obtain a polymer solution. The above mold is slowly dipped in this polymer solution so as not to mix air bubbles, and then pulled up. After that, the solvent is evaporated from the mold in a dryer at 60 ° C. This process is repeated to obtain a predetermined film thickness. Next, the stoppers at both ends are removed, and the silicone oil is removed. Roll the mold into a twist and reduce the diameter sufficiently, then remove the mold. Thereafter, the obtained membrane portion is washed and various assembling steps are performed according to the purpose to complete an intra-aortic balloon pump.

[0014]

Example 2 Next, a method of molding a blood chamber of a suck blood pump will be described. A mold as shown in FIG. 3 is manufactured by blow molding. The mold is made of low density polyethylene. This mold is filled with air to prevent deformation during dipping or drying,
Plug the inlet. Next, the mold is slowly dipped in the above polyether type polyurethane urea solution so that air bubbles do not enter. After pulling up the mold from the solution, the solvent is evaporated in a dryer at 60 ° C. This process is repeated to obtain a predetermined film thickness. After the solvent has dried, the mold is folded inside the membrane, made sufficiently small, and then taken out from the hole. After this, the membrane part is attached with a check valve and a housing for the air chamber to complete a blood pump.

[0015]

INDUSTRIAL APPLICABILITY The blow molding mold used for dipping molding of the present invention and the method for manufacturing a medical device using this mold are used for molding thin film products. It is possible to easily mold an artificial heart, a balloon pump, or the like, which has been difficult to remove, with stable quality.

[Brief description of drawings]

[Fig. 1] Mounting diagram of the auxiliary artificial heart

[Fig. 2] Balloon molding method

FIG. 3 Molding method of blood chamber

[Explanation of symbols]

 1. Blow molding mold (for balloon) 2. Polymer solution 3. Internally filled silicone oil 4. Stopper 5. Formed film 6. Blow molding mold wrapped for easy removal 7. Balloon molding coating 8. Blow molding mold (for blood chamber) 9. Deformation prevention plug 10. Polymer solution 11. Folded mold for easy removal 12. Blood chamber molding coating

Claims (2)

[Claims] 1. A mold in dipping molding,
A dipping molding mold, which is a hollow mold composed of a polymer material film wall having a thickness of 2 mm or less. 2. A medical device is obtained by dipping the mold according to claim 1 into a solution in which a polymer is dissolved, followed by drying to remove the solvent, forming a polymer film, and then removing the mold. Characteristic medical device manufacturing method.