JPH0218103B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION (Technical Field) The present invention relates to medical devices that have parts made of different materials joined together. (Prior art and its problems) Medical devices are generally made up of many parts made of different materials joined together. To give one example, a blood bag made of soft vinyl chloride, a blood bag made of soft vinyl chloride, tube, polypropylene drip barrel, flexible PVC tube, ABS resin or polypropylene hub, and stainless steel puncture needle are bonded using a solvent-based adhesive such as tetrahydrofuran (THF) or methyl ethyl ketone (MEK). , a ring blood set is constructed. When solvent-based adhesives are used in this manner, many problems arise as described below. (1) The adherend is damaged by the solvent and becomes brittle.
There is a risk of damage. (2) There is a risk that part of the adherend dissolved by the solvent may clog the flow path. (3) There is a concern about toxicity due to residual solvent. Medical devices in which many parts are joined together using solvent-based adhesives have many problems as described above, so there has been a desire to develop a technology that can join many parts together without using organic solvents. OBJECT OF THE INVENTION The object of the present invention is to bond parts made of different constituent materials without using conventional adhesives containing organic solvents, even in cases where it is difficult to bond parts with different constituent materials due to the adhesive used by one of the parts to be joined. The present invention aims to provide a medical device bonded with strong bonding strength. The present invention is a medical device having a tubular first part made of a soft material that can be bonded with a hardening adhesive, and a tubular second part made of a material that is difficult to bond with a hardening adhesive and joined to the first part. The joint between the first and second parts is formed by providing an annular recess in the open end surface of the second part, and includes opposing walls on the inner and outer sides of the recess, and opposing wall surfaces on the outer side. at least one rib formed in the recess and intersecting the axial direction; and the first part is inserted into the recess and engaged with the inner opposing wall so that the surface of the first part and the outer opposing wall of the second part are connected to each other. The present invention provides a medical device comprising a joining space formed by a wall surface and the rib, and a hardened portion of a curable adhesive that fills only the remaining gap in the joining space. DETAILED DESCRIPTION OF THE INVENTION There are a wide variety of medical devices to which the present invention can be applied, including medical devices having at least one joint such as a blood cycle set, a cycle fluid set, and a dialysis circuit. Hereinafter, the medical device of the present invention will be explained with reference to the accompanying drawings. As a preferred embodiment, a description will be given of a connection between a drip tube and a tube used in a blood ring set, a ring set, etc., but it is needless to say that the present invention is not limited thereto. The basic idea of the present invention is to use a curable adhesive instead of a conventional solvent-based adhesive. Curable adhesives have the property of adhering and curing after a predetermined period of time, and include, for example, those described below. That is, ultraviolet curable adhesive,
Examples include cyanoacrylate instant adhesives, epoxy resin adhesives, hot melt adhesives, and acrylic adhesives. By using such a curable adhesive, it is possible to obtain a structure that allows the parts to be joined with strong bonding strength even if one of the parts to be joined is made of a material that is difficult to bond with a curable adhesive. The inventors have discovered that this can be done, and have arrived at the present invention. In addition, adhesion difficulty means
Refers to materials for which sufficient adhesive strength cannot be obtained with adhesive alone. Figure 1 shows a tube that is the first tubular part used in blood circulation sets, fluid sets, etc.
This is a joined body of drip tubes that are parts, and the base end 2 and distal end 3 of the drip tube 1 are joined to tubes 4 and 5, respectively. In this configuration, tubes 4, 5 are generally constructed of soft vinyl chloride;
Although it is well bonded with a curable adhesive, the drip tube is made of polypropylene and is difficult to bond with a curable adhesive. Figures 2 and 3 show - of Figure 1, respectively.
A longitudinal section along the line and - line is shown. FIG. 2 is a cross section of the joint between the tip 3 of the drip tube 1 and the tube 5. In the present invention, an annular recess is provided in the open end surface of the distal end 3 of the drip tube 1, and the inside of the recess (inner cylinder) 6 having a diameter equal to or slightly larger than the inner diameter of the tube 5 and the inner cylinder An annular joining space whose radial distance is slightly larger than the wall thickness of the tube 5 is formed between the inner tube 6 and the outer tube 7. 8 is formed. Further, at least one circumferential rib 9 is formed on the inner circumferential surface 7a of the outer cylinder 7, that is, the opposing wall surface between the outer cylinder 7 and the tube 5, and on the side surface of the outer cylinder. The curable adhesive 10 completely fills the remaining gap between the tube 5 inserted into the tube 5 and the inner and outer cylinders 6 and 7 of the drip barrel 1. In this way, the drip tube 1 and the tube 5 are joined, and although it is difficult to bond the drip tube 1 with a hardening adhesive, the hardening adhesive 10 is firmly bonded to the tube 5. Inner peripheral surface 7 of outer cylinder 7 of drip tube 1
It enters between the ribs 9 formed in a, and this provides pull-out resistance, so that the two are joined with strong joint strength. In order to obtain bonding strength, the ribs 9 formed on the inner circumferential surface of the outer cylinder 7 of the drip tube may be discontinuous ring-shaped or continuous spiral-shaped, but if the curable adhesive 10 is A spiral shape is preferable so that it spreads throughout the remaining voids. FIG. 3 is a cross section of the joint between the proximal end 2 of the drip tube 1 and the tube 4, and is substantially the same as the joint shown in FIG. 2, so a detailed explanation will be omitted. The depth of the ribs is closely related to the ease with which it can be removed from the mold, and the number of ribs is also closely related to the pullout strength (joint strength). The bonding strength is related to the ratio of the surface area of the inner and outer cylinders when they have a smooth surface without ribs and the surface area of the inner and outer cylinders when ribs are provided, and the ratio is 1:1.1 to 1:1.5, More preferably 1:1.2~
It was found that a preferable bonding strength can be obtained when the ratio is 1:1.3. Note that the term "rib" refers to a convex part of a concavo-convex part provided in an annular continuous or discontinuous manner, or provided in a spiral shape. Further, the medical device of the present invention is finally sterilized by ethylene oxide gas or autoclave sterilization. In recent years, γ (gamma)
As sterilization by radiation began to be performed,
If an adhesive that is cured by gamma rays is used as the above-mentioned curable adhesive, bonding and sterilization can be performed at the same time. The structure shown in FIGS. 2 and 3 for joining parts with different adhesive properties using a curable adhesive was based on the experimental results described below. FIG. 4 shows joint structures having ribs of various shapes. The material of the tube is soft vinyl chloride resin, and the drip tube is made of polypropylene. The example in Figure 4a has six spiral ribs with a height of 0.1 mm, and the example in Figure 4b has a ring shape with a height of 0.2 mm with some discontinuities to remove air bubbles.
The example in Figure 4c is a continuous ring-shaped rib with a height of 0.3 mm, and the example in Figure 4d is a continuous ring-shaped rib with a height of 0.3mm.
Two 0.2mm ribs are formed. Five of these were prepared, using a UV-curable adhesive (UV-3607, manufactured by Toagosei Kagaku Co., Ltd.) as the adhesive, and sterilization was performed by irradiating γ-rays at 2.5 Mrad. The bonding strength was measured using an Autograph DCS-100 tensile tester manufactured by Shimadzu Corporation, immediately after sterilization.
After storage in a hot storage, it was measured by a tensile test at 50 mm/min. From Table 1 showing the results, the height of the rib is 0.2
If it is larger than mm, deformation may already occur during die cutting, and continuous ring-shaped items may not adhere well to the adhesive, leaving bubbles in some cases. Therefore, it can be seen that the structure shown in FIG. 4a exhibits the best effect. However, the devices shown in FIGS. 4b, 4c, and 4d, which are included in the present invention, can also be put to practical use.

[Table] Specific Effects of the Invention For the medical device of the present invention, a structure with high joint strength and good demoldability was selected from among the various configurations shown in FIG. 4. The structure is as shown. In such a structure, the adhesive used for bonding needs to be a hardening type. and,
The effectiveness is most significant when one of the parts to be joined is made of a material that is impossible or difficult to bond with a curable adhesive. By forming ribs as shown in Figures 2 and 3 on the surfaces to be joined of parts made of materials that are difficult to bond with a hardening adhesive, the hardening adhesive can penetrate and wrap around the ribs. harden with Therefore, when a force is applied in the pulling direction, the ribs inserted into the hard bonded portion act as resistance, increasing the bonding strength. Specific Effects of the Invention The medical device of the present invention provides many advantages over conventional techniques, as described below. (1) Because conventional solvent-based adhesives are not used to join parts, problems caused by solvents, namely:
This eliminates the dangers of material deterioration due to solvents, clogging of flow paths due to eluates, and toxicity due to residual solvents. (2) By using curable adhesives instead of solvent-based adhesives, polyolefin resins such as polypropylene and polyethylene, which were difficult to bond, can now be used as materials for medical devices such as drip tubes. Contribute to cost reduction with inexpensive materials. (3) In addition to using a hardening adhesive, ribs that can be easily cut out are formed on the side of parts made of materials that are difficult to bond with, and the anchoring effect of these ribs to the hardened adhesive area creates a large bond. Provides strength. By forming the ribs in a spiral shape rather than in a discontinuous ring shape, air escape during adhesive filling becomes better, and the adhesive spreads better, resulting in greater and more stable bonding strength. (4) If a gamma-ray curing type adhesive is used, curing and bonding can be performed at the same time as sterilization by gamma-ray irradiation, eliminating the need for other means such as UV irradiation equipment, and reducing the manufacturing process. It's convenient.

[Brief explanation of drawings]

FIG. 1 is a side view showing a combined body of an infusion tube and a tube as a representative example of the medical device of the present invention, and FIGS. 2 and 3 are the - line and - line in FIG. 1, respectively.
4 is a cross-sectional view of various configuration examples subjected to a joint strength test, and an enlarged cross-sectional view of a rib marked with a circle. Explanation of symbols, 1...Drip tube, 2...Proximal end, 3
... Tip part, 4, 5 ... Tube, 6 ... Inner cylinder,
7... Outer cylinder, 8... Joining space, 9... Rib, 1
0...Hardened adhesive.

Claims (1)

[Scope of Claims] 1. A first tubular part made of a soft material that can be bonded with a curable adhesive, and a second tubular part made of a material that is difficult to bond with a curable adhesive and is joined to the first part. In the medical device, the joint between the first and second parts is formed by providing an annular recess in the open end surface of the second part, and includes opposing inner and outer walls of the recess; at least one rib formed on the opposing wall surface and intersecting the axial direction;
The first component is inserted into the recess and engaged with the inner opposing wall to form a joining space formed by the surface of the first component, the outer opposing wall surface of the second component, and the rib, and the joining space. 1. A medical device comprising a hardened portion of a hardening adhesive that fills only the remaining void in the medical device space. 2. The medical device according to claim 1, wherein the curable adhesive is an ultraviolet curable adhesive. 3. The medical device according to claim 1 or 2, wherein the first component is a flexible medical tube.