JP2617192B2 - Method of manufacturing blood pump device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a blood pump device.

B. 2. Description of the Related Art In recent years, an artificial heart for assisting and temporarily replacing the function of the heart outside the body during open heart surgery or other surgery has been developed. For example, as shown in FIG. 5, a sack type blood pump device 11 is connected between the right atrium and the pulmonary artery of the heart 10 of the living body, and between the left atrium and the aorta.

This blood pump device 11 is a so-called sack type, which is mainly a pressure-resistant (for example, made of polycarbonate or polyurethane) housing outer case 1 and a flat bag-shaped sack type housed in the housing outer case in an airtight manner. Blood chamber 2. At an upper portion of the blood chamber 2, a blood introduction tube 3 and a blood extraction tube 4 are formed upward and substantially parallel to each other so as to communicate with the blood chamber. A flange 5 which forms a part of the housing is provided around the upper part of the blood chamber, and the blood chamber is hermetically housed in the housing outer case 1 by the flange. In addition, blood introduction tube 3
An artificial check valve (not shown) for preventing the backflow of blood is installed in each of the inside of the blood introduction pipe 4 through a ring-shaped valve seat. The blood introduced into the chamber 2 is discharged from the blood outlet tube 4. The pumping of the blood is performed through a port 8 provided at the bottom of the housing outer case 1.
For example, the introduction and discharge of compressed air and decompressed air are performed alternately, and the expansion and contraction of the blood chamber are repeated as the external pressure of the blood chamber changes. Each cannula 12 connected to the heart of the living body and each of the blood conduits 3 and 4 on the blood chamber 2 side are inserted from both ends of each connector 13 to the position of a ring-shaped flange 14 provided at the center thereof.

In manufacturing the blood pump device as described above, it is conceivable that the flange portion 5 and the blood introducing tube 3 or the blood introducing tube 4 are particularly joined by using an adhesive. However, when these flange portions 5 and the conduits 3 or 4 are particularly made of soft polyvinyl chloride,
There is no suitable adhesive for bonding such soft polyvinyl chlorides. That is, soft polyvinyl chloride contains, for example, dioctyl phthalate as a plasticizer,
In particular, components of medical equipment as described above are required to have flexibility, so that usually 60 parts by weight or more of dioctyl phthalate is contained. When trying to bond such soft polyvinyl chlorides to each other, the solvent in the adhesive migrates into the polyvinyl chloride of the adherend and swells to fuse the adherends. Since the plasticizer in the body has a large molecular weight, it is difficult to migrate, and therefore, even if it is adhered, its adhesive strength is small, and it easily peels off. Therefore, adhesives using a solvent are unsuitable especially for bonding between soft polyvinyl chlorides. Examples of adhesives that do not use a solvent include epoxy resins, polyurethanes, and rubber-based adhesives. However, they are different from polyvinyl chloride, have poor adhesive ability, and are all unsuitable.

Thus, the connection between the flange portion 5 and the blood introducing tube 3 or the blood introducing tube 4 is performed by a method described with reference to FIG. First, the blood introducing tube 3 made of soft polyvinyl chloride is inserted into the circular through hole 6 of the flange portion 5 separately formed of soft polyvinyl chloride (the blood outlet tube 4 is omitted because it is the same). A plastisol (paste) 9 of polyvinyl chloride is poured into and filled in the minute gaps 7 formed in the upper part of the region. Then, in this state, the plastisol 9 is gelled and further hardened by heating from the outside by a local heater (not shown), particularly at 140 to 240 ° C., whereby the flange portion 5 and the blood conduit 3 are connected. They are fixed (or fused) or bonded to each other. The dashed line 2 in the figure is a blood chamber integrally connected to the blood conduit 3 by a known slash molding method.

However, in such a manufacturing method, since the flange portion 5 and the blood conduit 3 are originally made of heat-insulating polyvinyl chloride, the contact area between the flange portion 5 and the blood conduit 3 and the plastisol filling during the external heating described above. Heat is not sufficiently and uniformly transmitted to the area. Therefore, in order to sufficiently gel and harden the sol 9, it is necessary to increase the heating temperature or lengthen the heating time, but this causes the flange portion 5 and the blood conduit 3 to undergo thermal deformation or thermal decomposition. There is a possibility.

Further, in the manufactured structure, the flange 5 and the blood conduit 3 are only fixed to each other only through the surface layer via the same type of polyvinyl chloride. Therefore, the blood conduit 3 is particularly likely to be deformed by the action of external pressure. When the pressure is applied to the flange 5
Directly in the fixing area. For this reason, the fixing region may be distorted or broken.

C. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a method of manufacturing a blood pump device that can perform heating locally and efficiently and can also increase the mechanical strength of a workpiece. It is intended to provide.

D. The present invention relates to a method for manufacturing a blood pump device having a blood conduit and a blood conduit fixing portion for joining and fixing the blood conduit, comprising: a polyvinyl chloride containing a structural viscosifying agent exhibiting thixotropy. A step of filling at least the bonding portion with a vinyl chloride resin paste composition in which a magnetic powder to be heated by induction heating is dispersed in a paste; and then, the magnetic powder is heated by induction heating. And gelling the polyvinyl chloride paste by the heat generated by the magnetic powder, and fixing the blood conduit to the blood conduit fixing portion.

E. Examples Hereinafter, examples of the present invention will be described.

As shown in FIG.
Compared to the example shown in the figure, both are fixed to each other by the polyvinyl chloride paste 19 in the contact area between the flange portion 5 and the blood introduction tube 3, but the ferromagnetic magnetic powder is contained in the polyvinyl chloride paste 19. Twenty are moderately distributed. Due to the presence of the magnetic powder, the heating of the fixing region by the high-frequency induction heating described later can be concentrated and sufficiently performed, and the gelation and hardening of the polyvinyl chloride plastisol 9 described later can be sufficiently performed and the flange portion 5 can be formed. It is possible to increase the fixing strength between the blood vessel 3 and the blood vessel 3 and to securely fix it. As described above, since the heating to the fixing region is performed efficiently and locally, even if the flange portion 5 and the like are formed of heat-insulating polyvinyl chloride, the flange portion 5 and the like are not affected by the heating. However, thermal deformation and thermal decomposition as described above do not occur.

The magnetic powder 20 is desirably a corrosion-resistant powder of, for example, stainless steel or silver, so as not to cause corrosion by hydrogen chloride generated by partial decomposition of the surrounding polyvinyl chloride during the above-mentioned heating.

Further, since the fixing area is made of the soft polyvinyl chloride itself, polyurethane, acrylic resin, epoxy resin, polyvinyl chloride (hereinafter sometimes referred to as PVC).
This is significantly more advantageous than using a general adhesive such as a solution. That is, when the adhesive is used, the plasticizer contained in the material on the side of the conduit 3 (and 4) gradually oozes out (adhesively bleeds out) into the adhesive after joining due to the difference in composition between the plasticizer and the adhesive. It is easy to be defective. This is particularly likely to be a problem when the soft polyvinyl chlorides or one of them is soft polyvinyl chloride as in this example. However, when fixed as described above, the problem of bleed-out does not occur, and the flange portion 5 can be firmly fixed. In addition,
Depending on the presence of the magnetic powder 20, the physical properties do not deteriorate due to the interface, and the magnetic powder 20 itself is stably present in the soft polyvinyl chloride 19.

FIG. 2 shows the entirety of the blood pump device 41 having the above structure. In this figure, the flange portion 5 shown in FIG.
It does not represent such an interface, since the anchorage 19 between the blood conduits 3 (and 4) is actually formed integrally without an interface. Further, according to this pump device, the flange portion 5 is fixed to the housing outer case 1 with the port 8 with the screw 64 via the stainless steel ring plate 62. At this time, the lower surface of the flange portion 5 If is formed on a smooth surface, the adhesion to the case 1 is large, and the sealing property is good. Here, the sack portion 2 and the blood introduction tube 3
The outlet pipe 4, the flange portion 5, and the connecting portion 56 may be formed of polyvinyl chloride or polyurethane, and the case 1 may be formed of polycarbonate, polyurethane, or epoxy resin.

Next, a method of manufacturing the blood pump device according to the present embodiment will be described.

First, a flange portion 5 made of soft polyvinyl chloride as shown in FIG. 3 is produced by a known molding method. However, a ring-shaped inclined surface 21 having a shape of a truncated cone is formed around the upper end side of the circular hole 6.

Then, the blood introducing tube 3 and the blood introducing tube 4 are inserted from below as shown in FIG. 4A, and are brought into close contact with the flange portion 5 as shown in FIG. 4B.

Next, as shown in FIG. 4C, a coiled high-frequency magnetic field generator 22 is arranged around the flange portion 5. Then, the polyvinyl chloride plastisol 9 is filled in the minute gap 7 having an upper end formed by the inclined surface 21 and having a width of 0.7 mm. A magnetic powder 20 is dispersed in the plastisol 9. The details of this plastisol will be described later.

Thereafter, the magnetic powder 20 dispersed in the plastisol 9 was exposed to a high-frequency magnetic field by applying a high-frequency current to the coil of the high-frequency magnetic field generator 22, thereby inducing the surface layer of the magnetic powder 20. Heat is generated by eddy current loss and hysteresis loss. As a result, only the magnetic powder 20 is heated.
Is locally heated to a predetermined temperature (particularly 140 to 240 ° C.) to cause gelation and further curing.

In the above, the amount of the magnetic powder 20 in the PVC paste varies depending on the particle size, but is 10 per 100 parts by weight of the resin.
The content is preferably up to 500 parts by weight, more preferably 20 to 200 parts by weight. Ten
When the amount is less than part by weight, the high-frequency induction heating and curing is inferior, and when it exceeds 500 parts by weight, the processability is inferior, which is not preferable.

The plastisol (paste resin) 9 has a remarkable decrease in viscosity in the early stage of heating (for example, 4000 c.p.
To 200 c.p. in ~ 60 seconds) to prevent runoff, sedimentation of the magnetic powder 20, or sagging.
3 to 10 parts of a thixotropic structural viscous agent (also referred to as a gelling agent) such as hydrous silicic acid, anhydrous silicic acid, organically modified bentonite, and dibenzylidene sorbitol are blended. The sedimentation of the magnetic powder causes non-uniform heating due to uneven distribution of the magnetic powder in the fixed region, which leads to a reduction in bonding reliability. In order to further increase the adhesiveness, an epoxy resin or an acrylic resin may be partially mixed.

In this example, 100 parts by weight of a polyvinyl chloride paste, 10 parts by weight of a strong thixotropic agent (trade name: E-CON), 70 parts by weight of dioctyl phthalate as a plasticizer, calcium-
3 parts by weight of a zinc-based heat stabilizer and 60 parts by weight of a 125-250 mesh stainless steel powder.

The conditions of high-frequency induction heating vary greatly depending on the oscillation and coil shape, but the frequency is 450 kHz and the output current is 0.05 to 0.2 A.
And heating for 5 to 20 minutes to obtain sufficient adhesive fusion.

If the flange portion 5 and the blood conduit 3 (and 4) are fixed by high-frequency induction heating in this way, the heating can be localized and the sol 9 can be more concentrated enough to gel in the vicinity. it can. That is, the heat generated by the magnetic powder 20 is sol 9
, Heat efficiency becomes very good, and thermal effects on other parts can be eliminated. Moreover,
Since the heat generating portion is a local portion, cooling can be easily performed and heat management can be sufficiently performed.

Next, as shown in FIG.
The mold 32 is attached to the lower ends of the and. This mold 32 has a molding space 43 for a blood chamber (that is, a sack portion), and is integrally provided with a protruding portion 36 that protrudes downward in a curved shape at the center.

Then, as shown in FIG. 4E, the mold 32 is passed through the conduit 3 or 4.
A polyvinyl chloride plastisol (for example, Zeon 131A manufactured by Nippon Zeon Co., Ltd.) 59 as a molding material is put into the inside, and filled to a predetermined level. Then, heating is performed in a hot-air circulation oven, and heat 63 is uniformly applied to the entire mold 32. In this case, the heating temperature is from 70 to 150 ° C, and more preferably from 80 to 110 ° C. When the polymer used for the plastisol is not a vinyl chloride homopolymer but a copolymer having a low thermal softening point, such as a vinyl chloride-vinyl acetate or vinyl chloride-vinyl ether copolymer, the temperature may be relatively low. The processing time is preferably several minutes to 30 minutes. If the heating is insufficient or the treatment time is short, the gelling layer is too thin, and if the treatment time is too high or the treatment time is too long, the gelling layer is too thick, which is not preferable.

The portion 2 of the plastisol 59 that is in contact with the mold 32 is gelled by heat. Next, the excess plastisol in mold 32
Discharge 59 and heat cure. A preferred temperature range at this time is 160 to 240 ° C, more preferably 190 to 210 ° C.
° C. If the temperature is lower than 160 ° C., the curing is insufficient, causing a decrease in mechanical strength. At 240 ° C. or higher, the polymer may be decomposed.

Then, after cooling, the mold 32 is separated and released,
As shown in FIG. 4F, it is possible to obtain a molded body in which the flange portion 5, the conduits 3, 4 and the blood chamber 2 are integrally formed without a joint. The molded body has a telescopic sack 2 and a telescopic connecting portion 56 between the two conduits 3-4. Since the connecting portion 56 also expands and contracts at the same time as the sack portion 2, the stroke capacity as a pump, that is, the discharge amount increases, and even when a low flow rate region is used, thrombus does not adhere and the performance is greatly improved.

Although the above example is an example in which the PVC paste composition used in the present invention is used for assembling the blood pump device, the paste resin used in the present invention can be used for other medical devices, and polyvinyl chloride. It can be used for joining polyvinyl chloride and other polymers as well as joining them together. Furthermore, in addition to joining, it is also possible to perform local molding using the PVC paste composition used in the present invention. The composition of the paste composition is not limited to the above examples, and may be any appropriate composition according to the purpose based on the technical idea of the present invention. In addition to the above-mentioned magnetic powder,
A powder of a substance heated by induction heating (for example, a powder of a metal oxide called ferrite) may be used. Further, in order to avoid a spark at the time of high-frequency oscillation due to poor dispersion, a material subjected to a surface treatment with a resin acid or the like may be used. A particle diameter of 1 to 100 μm can be used. If the particle diameter is smaller than this, sparks are likely to occur. When the particle diameter is large, sedimentation and separation during storage or heat processing is liable to occur. Therefore, it is particularly important to mix the above-mentioned gelling agent. Therefore, it is necessary to select an appropriate particle size according to the heating conditions, but if it exceeds 100 μm, it becomes difficult to obtain a good dispersion.
Various conditions for the above-described induction heating can be selected.

F. Effect of the Invention As described above, the vinyl chloride resin paste composition used in the present invention has the magnetic powder heated by induction heating dispersed in the polyvinyl chloride paste,
The powder is heated by induction heating, and by this heating,
Even if an insulative object is present, the paste can be locally and easily and efficiently heated to gel and further harden. Further, since the polyvinyl chloride paste contains a structural viscosifying agent exhibiting thixotropic action, it is possible to prevent a significant decrease in viscosity in the early stage of the above-mentioned heating, and to prevent sedimentation of the magnetic powder due to the decrease in viscosity. You.
As a result, the uniform dispersion of the magnetic powder is maintained, and the gelation and curing of the polyvinyl chloride paste are uniformly performed, and the joining is ensured. Further, there is no problem that the vinyl chloride paste flows out in the early stage of the heating to cause poor adhesion, or the flowing out vinyl chloride paste adheres to a portion other than the bonding area. In addition, since the same kind of paste is used as a component to join polyvinyl chloride, and there is no need to use a solvent, the joining is ensured, the finish of the joining side surface is smooth, and the mechanical properties of the joint are mechanical. A highly reliable blood pump device that can be joined with high strength and high reliability is manufactured.

[Brief description of the drawings]

1 to 4 show an embodiment of the present invention, wherein FIG. 1 is a sectional view of a main part of a blood pump device, FIG. 2 is a sectional view of the whole device, and FIG. FIG. 4A, FIG. 4B, FIG. 4C, FIG. 4D, FIG. 4E and FIG. 4F are cross-sectional views at each stage showing a method of manufacturing a blood pump device in the order of steps. It is. 5 and 6 show a conventional example, FIG. 5 is a schematic front view showing a use state of the blood pump device, and FIG. 6 is a sectional view of a main part of the blood pump device. In addition, in the reference numerals shown in the drawings, 1 ... case 2 ... blood chamber 3, 4 ... blood conduit 5 ... flange section 9 ... plastisol (paste) 19 ... fixed section 20 ... metal powder 22 ... high frequency It is a magnetic field generator.

Claims (1)

(57) [Claims] When manufacturing a blood pump device having a blood conduit and a blood conduit fixing part for joining and fixing the blood conduit, a polyvinyl chloride paste containing a structural viscosifying agent exhibiting thixotropy is used. A step of filling at least the joining portion with a vinyl chloride resin paste composition in which the magnetic powder to be heated by the induction heating is dispersed, and then, the induction heating causes the magnetic powder to generate heat,
Causing the polyvinyl chloride paste to gel by the heat generated by the magnetic powder, and fixing the blood conduit to the blood conduit fixing portion.