JP2001212204A - Stopper for fluid infusion and method of manufacturing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stopper for fluid infusion of stable quality at a low cost with fewer manufacturing processes by an insert molding. SOLUTION: The stopper consists of a rubber stopper and a plastic supporting part. The supporting part is manufactured by an insert molding so that an external cylinder, an upper parapet, which is protruded into inward from the external cylinder and engages with the above rubber stopper, and a lower parapet may make a U shaped form at cross-section. The thick part C of the above external cylinder is molded larger than the thick part A of the upper parapet and the thick part B of the lower parapet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plug comprising a rubber stopper and a plastic support, wherein the rubber stopper is set in an injection mold and the support forming the outer shell is formed in one step. The present invention relates to a highly safe and highly safe plug having a rubber plug and a support that are integrated by an insert molding method and a method of manufacturing the same.

[0002]

2. Description of the Related Art Infusion plugs have various shapes depending on the purpose of use or required characteristics. Conventionally, the most common shape is a plug shown in cross section in FIG. In the figure, a plug 10 is composed of a rubber plug 11 and a plastic support 12 fitted and supported by the rubber plug 11.
Is composed of an inner cylinder 13 and an outer cylinder 14.

A method of manufacturing a plug having such a shape is to combine the rubber plug 11, the inner cylinder 14 and the outer cylinder 14 and integrate them by a hot plate or ultrasonic fusion, or to form an outer cylinder 13
A method is adopted in which a rubber plug 11 is combined with a rubber plug 11, the plug is set in an injection mold, and the inner cylinder 13 is insert-molded to integrate the plug. However, in such a conventional method, the number of manufacturing steps is large, the number of facilities is large, and the manufacturing cost is high.

[0004]

SUMMARY OF THE INVENTION The present invention is an improvement of the conventional method of manufacturing a plug, in which a rubber plug is set in an injection molding die, and an inner cylindrical portion and an outer portion of a plastic support are provided. It is intended to provide a method of manufacturing an integrated plug body by insert-molding a cylindrical part in one step.This method makes it possible to sufficiently fit the rubber stopper and the plastic support and significantly reduce the number of manufacturing steps. Intend.

[0005] A method of manufacturing a support by insert molding is already known. However, in the conventional method, a rubber plug and an opening portion that is not covered with a plastic support supported in a mold are fixed with upper and lower pins. A molten high-viscosity plastic is injected into the cavity corresponding to the support at high pressure and high speed. At this time, the flange portion of the soft rubber stopper is deformed or displaced, and a stopper is deviated from an intended position, and there is a problem that the quality required for the stopper cannot be sufficiently satisfied.
For example, in the invention of Japanese Patent Application Laid-Open No. 8-252297, a device for holding a rubber plug supporting pin or plate in a mold is used to keep the shape of the rubber plug. However, in this method, the mold is complicated, and in industrial production, there are many problems in obtaining a plug of stable quality with a multi-cavity mold at low cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a plug at a low cost with a stable quality by reducing the number of manufacturing steps by an insert molding method and a plug obtained by the manufacturing method.

[0007]

SUMMARY OF THE INVENTION The present invention comprises a rubber stopper and a plastic support forming an outer shell, the support protruding inward from the outer cylinder and a flange of the rubber stopper. The plug body is insert-molded so that the upper and lower sandwiching wall portions to be fitted with the outer tubular portion together with the outer tubular portion form an integral body having a substantially U-shaped cross section. Is a plug for infusion characterized by being formed larger than the thickness A of the upper sandwiching wall portion and the thickness B of the lower sandwiching wall portion.

Still another aspect of the present invention comprises a rubber stopper and a plastic support forming an outer shell thereof, the support protruding inward from the outer cylinder and fitting with a flange of the rubber stopper. A method of manufacturing a plug body in which the upper sandwiching wall portion and the lower sandwiching wall portion are formed into an integral body having a substantially U-shaped cross section, comprising: (1) disposing a rubber stopper at the center of the lower mold; (2) The space shape corresponding to the support formed by the rubber stopper and the lower mold and the upper mold is such that the thickness C1 corresponding to the outer cylinder portion is the thickness A1 corresponding to the upper sandwiching wall portion, A step of clamping the upper and lower dies so as to have a thickness larger than the thickness B1 corresponding to the sandwiching wall. (3) A step of injecting plastic from an injection gate into a space corresponding to the support of the dies. A method for producing a plug for infusion characterized by the following.

Hereinafter, the present invention will be described with reference to examples. FIG. 1 shows a cross-sectional view of the plug of the present invention. In the figure, a plug 1 comprises a rubber plug 2 and a plastic support 3 forming the outer shell of the rubber plug 2. The support 3 includes an outer cylinder 3c and the outer cylinder 3c.
c, an upper clamping wall 3a and a lower clamping wall 3b which are fitted in the flange 2a of the rubber plug 2 and which protrude inward. The outer cylindrical portion 3c, the upper sandwiching wall 3a, and the lower sandwiching wall 3b form a substantially U-shaped cross section and are fitted to the rubber stopper flange 2a to hold the rubber stopper 2 in close contact.

Here, the thickness C of the outer cylindrical portion 3c is equal to the upper sandwiching portion 3a.
And the thickness C of the lower sandwiching wall portion 3b is larger than the thickness A. Preferably, the thickness C is 1.2 times or more and 3 times or less of the thickness A or the thickness B. Here, the thickness is defined as the minimum thickness at each part. In addition, it is desirable that a flange 4 projecting outward from the outer cylindrical portion 3c be formed on the support 3 so as to be connected to the infusion container. Further, a pair of projections 3d can be formed on the sides of the upper sandwiching wall 3a and the lower sandwiching wall 3b which are in contact with the rubber plug to prevent the rubber plug from falling off.

Next, a method for manufacturing a plug according to the present invention will be described with reference to FIG. The rubber stopper 2 is placed on the lower mold 5 corresponding to the outer shape of the stopper. An upper mold 6 corresponding to the upper outer shape of the plug is disposed above. Therefore, the lower mold 5 is raised to clamp the upper and lower molds to form a space in the mold corresponding to the shape of the support. Here, the thickness C of the outer cylinder portion is larger than the thickness A of the upper sandwiching wall portion and the thickness B of the lower sandwiching wall portion, and is preferably in the range of 1.2 times or more and 3.0 times or less. The mold is set. Then, molten plastic is injected into the mold space from the injection gate 7 of the upper mold. Injection conditions can use usual conditions, for example, the injection temperature is in the range of 190 to 220 ° C for polypropylene and 180 to 210 ° C for polyethylene, and the injection pressure is 20 to 40M.
Pa.

By constructing the mold as described above, at the time of injection molding, the molten plastic injected into the mold is filled in the outer cylindrical space 3c 'having low flow resistance, and then the upper sandwiching wall space 3a' and Upper and lower sandwiching walls are formed, which flow evenly in the direction of the lower sandwiching space 3b 'and are fitted in a stable manner with the flange of the rubber plug.

Here, it is preferable that the thickness C1 of the outer cylindrical space is 1.2 times or more the thicknesses A1 and B1 of the upper and lower sandwiching spaces. If less than 1.2 times, outer cylinder space 3
When c 'is not filled with molten plastic, it flows unevenly into the upper and lower sandwich walls, and parallel flow to the upper and lower sandwich walls cannot be maintained. Displacement occurs, and a stable plug cannot be obtained. On the other hand, if it exceeds three times, an unnecessarily thick wall is formed in the outer cylindrical portion, and the manufacturing cost is increased. More preferably, it is in the range of 1.4 to 2.0 times.

Next, in the present invention, in order to promote the parallel flow of the molten plastic at the upper sandwiching wall 3a and the lower sandwiching wall 3b of the rubber stopper, the flange of the rubber stopper has a rectangular, circular, arc-shaped cross section. 3 (a), 3 (b), 3 (a), 3 (b), 3 (b), 3 (f), 3 (f), 3 (f), 3 (f), 3 (f), 3 (f), 3 (f), 3 (f), 3 (f), 3 (f), 3 (f), 4 (f), 3 (f),
It is preferable to form as shown in (c). Further, it is desirable that a concave groove for fitting with the projection 3d of the support is formed in the flange portion 2a of the rubber plug.

In the present invention, in order to improve the flow balance of the molten plastic to each part of the support, the cross-sectional shape of the flange portion of the rubber stopper can be changed from vertically symmetric to vertically asymmetric.

Further, the thickness of the outer cylinder portion below the gate 7 into which the molten plastic is injected and the thickness of the outer cylinder portion at the target position are as follows:
It may be different as long as a uniform flow can be maintained in the upper and lower wall portions.

The stopper connected to the infusion bag stores the drug solution in the infusion bag, and detaches the rubber stopper from the support by the pressure when the injection needle is inserted into the rubber stopper of the stopper during use.
Liquid leakage from the interface must not occur. If the rubber stopper is not held in place on the support, there is a danger as described above. In the plug manufactured by the method of the present invention, since the rubber plug is held in a predetermined position, a stable plug having a high quality without problems such as detachment of the rubber plug and liquid leakage can be obtained economically. Can be

The rubber plug of the plug of the present invention may be a diene rubber such as a copolymer containing polyisoprene, polybutadiene and a diene monomer as main components, a butyl rubber, and the like.
A rubber stopper obtained by vacuum-pressing a rubber component such as EPDM, a rubber stopper laminated with a resin film, and a rubber stopper made of a thermoplastic elastomer molded by an injection molding machine can also be used.

As the support for the plug, any plastic having good melt flow properties can be used.
Particularly, polyolefin resins such as polyethylene and polypropylene are preferable.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Production of rubber stopper The rubber composition shown in Table 1 was molded by a vacuum press method, and FIG.
The rubber stopper having the shape shown in the following was produced. 2. Insert molding Injection molding with the rubber stoppers arranged in the upper and lower molds forming the cavity of the support shown in FIG. 2 and the upper and lower surfaces of the rubber stopper corresponding to the open part as a stopper fixed with upper and lower pins (Cylinder temperature: 200 ° C., injection pressure: 30 MPa) to produce a plug. The plastic used for injection molding is Novatec HD HJ490 (manufactured by Nippon Polychem).
Table 2 shows the specifications of the plug. 3. Evaluation of plug The plug was cut at the center, and the shape retention of the flange of the rubber plug on the cut surface was observed.

◎ The flange portion of the rubber stopper is located as specified. ○ The flange of the rubber stopper is located almost as specified.

Δ The state where the flange portion of the rubber stopper is considerably displaced up and down. × The state in which the flange of the rubber stopper is largely displaced up and down.

[0023]

[Table 1]

[0024]

[Table 2]

Table 2 shows the evaluation results. It can be seen that the plugs of the present invention have no positional deviation inside the plug.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0027]

According to the present invention, since the shape of each part of the support is defined as described above, the flow of the molten plastic to each part of the support during the insert molding becomes smooth, and the rubber stopper is accurately fitted at a predetermined position. There is no danger of detachment of the rubber stopper and liquid leakage, and a stopper having a stable quality can be obtained. On the other hand, the manufacturing cost is reduced because a manufacturing method in which molding is performed in one step is adopted.

[Brief description of the drawings]

FIG. 1 is a sectional view of a plug according to the present invention.

FIG. 2 is a schematic sectional view of a mold for producing the plug of the present invention.

FIG. 3A is a cross-sectional view of a rubber stopper used for the stopper of the present invention. (B) is a sectional view of a rubber plug used for the plug of the present invention. (C) is a sectional view of a rubber plug used for the plug of the present invention.

FIG. 4 is a sectional view of a conventional plug.

[Explanation of symbols]

1 stopper, 2 rubber stopper, 3 support, 3a outer cylinder, 3
b Upper clamping wall, 3c Lower clamping wall, 3d projection, 4 flange, 5 lower mold, 6 upper mold.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 3E084 AA12 AB05 BA02 CB01 CC08 EA03 EB03 EC03 EC09 EC10 FA09 HB01 HC03 HD04 KB01 LA01

Claims (3)

[Claims] 1. A rubber stopper and a plastic support forming an outer shell thereof, the support protruding inward from the outer cylinder and being fitted into a flange of the rubber stopper. The thickness of the outer cylinder is C, and the thickness of the upper cylinder is the thickness of the upper wall. A plug for infusion characterized in that it is formed to be larger than A and the thickness B of the lower sandwiching wall. 2. A method according to claim 1, wherein the thickness of the outer cylinder is at least 1.2 times and not more than three times the thickness of the upper wall and the thickness of the lower wall. The plug for infusion according to the above. 3. A rubber stopper and a plastic support forming an outer shell thereof, said support protruding inward from said outer cylinder and being fitted into a flange of said rubber stopper. (1) A step of disposing a rubber stopper at the center of a lower mold (2) in a method of manufacturing a plug body in which an upper part and a lower sandwiching wall form an integral body having a substantially U-shaped cross section. The space shape corresponding to the rubber stopper and the support formed by the lower mold and the upper mold is such that the thickness C1 corresponding to the outer cylinder portion is the thickness A1 corresponding to the upper sandwich wall portion, and the thickness C1 corresponding to the upper sandwich wall portion. (3) a step of injecting plastic from an injection gate into a space corresponding to a support of the mold so that the upper mold and the lower mold are clamped so as to be larger than the corresponding thickness B1. Of producing a transfusion plug.