JP2004083028A - Stopper for container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stopper for a container, which well prevents liquid leakage upon sticking or pulling a needle into or out from the stopper after it is sterilized under high temperature and pressure. <P>SOLUTION: A stopper body 2 made of a thermoplastic elastomer has an outer diameter larger than the inner diameter of an outer cap 1, and a needle can be stuck into the stopper body 2, which is press-fitted into the outer cap 1. Constantly compressed by the outer cap 1, the stopper body 2 retains an internal stress. When the needle is stuck into the stopper body 2 after it is sterilized under high temperature and pressure, an elastic restitutive force resulting from the internal stress closes an opening formed on the stopper body 2 when a sticking spot is cut open, thereby prevents the leakage of liquid in the container. Also, the sticking spot is closed by the elastic restitutive force after the needle is pulled out, so the leakage of the liquid does not occurs as well. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a stopper for needle puncture used in the mouth of a container such as a medical or medicinal bottle or bag containing an infusion solution such as an amino acid or an electrolyte or a solution of a freeze-dried preparation.
[0002]
[Prior art]
This type of stopper is mainly made of rubber such as butyl rubber, isoprene rubber, butadiene rubber, and natural rubber, but this requires vulcanization and washing steps, so processing costs are high, and rubber stoppers are also used. Since the stopper body and the outer cap surrounding the stopper body are made of dissimilar materials, there is also a problem in separate disposal.
[0003]
In recent years, many medical and medical stoppers made of thermoplastic elastomers have been developed in order to solve the disadvantages of such rubber stoppers. For example, there is a stopper that prevents liquid leakage by molding the plug body with a thermoplastic elastomer and then insert molding the outer cap to increase the internal pressure of the thermoplastic elastomer plug body. Further, there is a method in which a needle piercing portion is manufactured by molding an outer cap of a stopper and then injection-molding a needle piercing portion with an injection pressure of 500 kg / cm 2 or more of a molten resin of a thermoplastic synthetic resin (Japanese Patent Laid-Open No. 2000-2000). No. 140068). There is also a stopper in which a plug body and an outer cap made of a thermoplastic elastomer are separately molded and assembled.
[0004]
[Problems to be solved by the invention]
However, any of the above-mentioned stoppers made of thermoplastic elastomers are always subjected to high-temperature and high-pressure sterilization before they are used for injection or infusion needles. In some cases, liquid leakage may occur after the needle is pierced, or the needle holding force at the time of needle piercing may be lost.
[0005]
In addition, when a medicinal solution is administered to the human body in a medicinal container using a stopper of this type, a medicinal solution is administered by connecting the human needle with a connecting pipe from a resin needle pierced into the medicinal container such as an infusion set / catheter. From the distance, importance is attached to the needle holding force when the resin needle is inserted into the stopper by its own weight such as the connecting pipe and the connector. Conventional stoppers made of thermoplastic elastomer increase the needle's holding power by increasing the elastomer hardness of the stopper body to increase the needle holding force, or increasing the stopper body by making the stopper body thicker than necessary. When the thickness of the plug body is increased, the manufacturing time and the material cost of the plug body are increased, and the cost is increased.
[0006]
Therefore, it is an object of the present invention to prevent liquid leakage even when a needle is pierced or removed after high-temperature and high-pressure sterilization, and to reduce the puncture resistance even if the thickness of the stopper body is not so thickened. An object of the present invention is to provide a stopper for a container which can sufficiently secure a holding force.
[0007]
[Means for Solving the Problems]
The stopper of the container of the present invention is characterized in that a needle pierceable plug main body having an outer diameter larger than the inner diameter of the ring-shaped outer cap and made of a thermoplastic elastomer is press-fitted inside the outer cap. Things.
[0008]
In this case, it is preferable that the ratio of the inner diameter of the outer cap to the outer diameter of the plug body is 1: 1.05 to 1.25.
Further, it is preferable that the stopper main body is formed in a cross-sectional shape in which the outer peripheral portion of the needle stick region is thicker than the central portion and gradually becomes thinner from the outer peripheral portion toward the central portion.
[0009]
When the plug body having a larger outer diameter than the inner diameter of the outer cap and made of a thermoplastic elastomer is press-fitted into the outer cap as in the above configuration, the plug body has an internal stress constantly compressed by the outer cap. It is in. Therefore, even after high-temperature, high-pressure sterilization, when the needle is pierced into the stopper body, even if the pierced portion is cut open, it is closed by the elastic restoring force due to the compressed internal stress. Does not leak, and the needle holding force increases. Further, even after the needle is removed from the stopper body, this portion is closed by the elastic restoring force due to the compressed internal stress, so that the liquid inside does not leak.
[0010]
If the stopper main body is formed in a cross-sectional shape in which the outer peripheral portion of the needle stick region is thicker than the central portion and becomes gradually thinner from the outer peripheral portion toward the central portion, high-temperature and high-pressure sterilization treatment is performed. Later liquid leakage can be more effectively prevented, and the needle holding force can be further enhanced.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
A preferred embodiment of the present invention will be described with reference to the drawings. 1 is a sectional view of a stopper according to one embodiment, FIG. 2 is a sectional view showing an outer cap and a stopper body of the stopper of FIG. 1 in a separated state, and FIG. 3 is a sectional view of a stopper body of another embodiment. .
[0012]
1 and 2, a stopper for a container according to the present invention is made of a thermoplastic elastomer having an outer diameter b larger than an inner diameter a of the outer cap 1 in a free state. The plug main body 2 that can be pierced is press-fitted.
[0013]
As the thermoplastic elastomer used as the material of the plug body 2, at least one of a styrene-based elastomer, an olefin-based elastomer, and a polyester-based elastomer is selected, and used alone, in combination, or in a mixture. The plug body 2 made of a thermoplastic elastomer is formed of a thermoplastic elastomer having a softness of an elastomer hardness (JIS K6301) of 15 to 70 degrees, more preferably 25 to 45 degrees.
[0014]
2, the ratio of the inner diameter a of the outer cap 1 to the outer diameter b of the plug body 2 is preferably a: b = 1: 1.05-1.25. When the outer diameter b of the plug body 2 exceeds 1.25 times the inner diameter a of the outer cap 1, it becomes difficult to press-fit the plug body 2 into the outer cap 1. Specifically, for example, the inner diameter a of the outer cap 1 is 23.18 mm, and the outer diameter b of the plug body 2 is 27.0 mm.
[0015]
In FIG. 2, the plug body 2 is formed in a biconcave lens shape in cross section, in which the thickness t1 of the outer peripheral portion of the needle stick region is thicker than the thickness t2 of the central portion and gradually becomes thinner from the outer peripheral portion toward the central portion. ing. In the center of the upper surface of the needle sticking area of the plug body 2 and in the vicinity of the center, an appropriate number of needle sticking designation portions 8 for setting a needle sticking position are provided. A concave portion 9 is formed on the lower surface of the plug main body 2 so as to face the needle sticking designation portion 8.
It is preferable that the ratio of the thickness t1 of the outer peripheral portion to the thickness t2 of the central portion of the needle stick area of the stopper body 2 in the free state is 1: 0.3 to 0.95. Specifically, for example, the outer peripheral portion thickness t1 of the needle stick region of the stopper main body 2 is set to 5.5 to 6.5 mm, and the central portion thickness t2 is set to 2.4 to 5.2 mm. In this case, the thickness t3 of the needle sticking designation section 8 is set to 0.25 to 0.45 mm.
[0016]
The top opening of the outer cap 1 is closed by a top plate (pull top) 3 with a pull tab 5 so that it can be pulled open. The top plate 3 is integrally formed with the outer cap 1 via a thin tear-off portion (score) 4 and a ring-shaped pull tab 5 is integrally formed on the upper surface of the top plate 3. By lifting the pull tab 5 with a finger, the torn portion 4 of the top plate 3 is torn and the top surface of the outer cap 1 can be pulled open. In this case, the tearing force applied to the pull tab 5 is set to 4.5 kg or less, more preferably 3.5 kg (moving by 20 mm / 60 seconds) so that the top plate 3 can be easily torn.
[0017]
As shown in FIG. 1, a stopper ring 7 having a film (membrane) 6 having a thickness of 50 to 350 μm is fitted on the lower surface side of the plug main body 2 in the outer cap 1, and at this time, as shown in FIG. A stopper ring 7 having a film 6 of 50 to 350 μm is integrally formed on the lower surface of the plug body 2 by insert molding, and then fitted into the outer cap 1 together with the plug body 2 from its open bottom. At this time, if the upper and lower vertical grooves 10 are provided in several places on the inner surface of the outer cap 1 so that the inside air can be released from the grooves 10 when the plug body 2 is press-fitted, the plug body 2 is press-fitted. Easy to do. When fitting the stopper ring 7, an annular ridge 11 is provided on the outer periphery of the stopper ring 7, and the ridge 11 is fitted into a concave groove 12 provided on the lower inner periphery of the outer cap 1.
[0018]
The stopper with the above configuration is used by welding the lower end of the outer cap 1 to the mouth of a container such as a medical or medical bottle or bag. At this time, the same kind of resin material as the outer cap 1 of the stopper, the stopper body 2 and the stopper ring 7 is used as the material of the container so that there is no need to separate and discard, and the recycling is advantageous.
[0019]
It is preferable to select a thin film having a thickness of 50 to 350 μm as the film 6 to be attached to the stopper ring 7 for the following reason.
The purpose of attaching the film 6 to the stopper ring 7 is to prevent a broken piece which is likely to be caused by a coring phenomenon in which a part of the stopper body 2 is broken at the time of needle sticking or needle removal, and to prevent a chemical solution leakage due to an increase in internal pressure during high temperature sterilization processing. For. The film 6 is integrally formed on the upper end surface of the opening of the stopper ring 7 by insert molding. At this time, the material selected as the molding material of the film 6 is polypropylene (PP) having a thickness of 350 μm or polyethylene (PE) having a thickness of 450 μm. Thick ones are the minimum wall thickness that allows resin flow during film formation. However, in the case of the film 6 having a thickness of more than 350 μm, if the stopper body 7 is previously formed into a stopper ring 7 integrally formed with the film 6 by assembling as a stopper, the needle puncture strength becomes 6.0 kg or more. This has a drawback in that a strong force is required when piercing a resin needle at a medical site, and it is difficult for women such as nurses to use it.
[0020]
When the plug body 2 is insert-molded into the stopper ring 7 with the film 6, the difference between the shrinkage degree of the elastomer of the stopper body 2 and the shrinkage degree of the molding resin of the stopper ring 7 causes the thermoplastic elastomer stopper body after sterilization. 2 is pulled by the molding resin of the stopper ring 7 and causes liquid leakage. For example, the shrinkage rate of the styrene-based elastomer that is the molding material of the plug body 2 is 25 to 35/1000%, and the shrinkage rate of the polypropylene-based resin that is the molding resin of the stopper ring is 8 to 16/1000%. When the stopper main body 2 is cut by a needle stick, the cut portion is pulled outward by the film 6 having a thickness of more than 350 μm attached to the upper end face of the opening of the stopper ring 7 and opens, causing a liquid leak from the portion.
[0021]
However, when a film 6 having a thickness of 50 to 350 μm is used as the film 6 to be insert-molded or welded to the stopper ring 7, the needle stick resistance is suppressed to 4.5 kg or less, and the entire thin film 6 is formed of the thermoplastic elastomer plug body 2. Since it is integrated along the lower surface, it is advantageous for preventing liquid leakage.
[0022]
An additive such as a softening agent is contained in the thermoplastic elastomer of the material of the plug body 2. When the plug body 2 is press-fitted into the outer cap 1, the additive oozes out, and after the press-fitting, the additive ages. The range of selection of the material of the thermoplastic elastomer is restricted due to elution. Therefore, as shown in FIG. 3, as a film 6 having a thickness of 50 to 350 μm to be attached to the stopper ring 7 so as to have a degree of freedom in selecting a material of the thermoplastic elastomer, two first and second films 6 a and 6 b are provided. Use Then, the second film 6b is integrally welded to the lower surface of the plug body 2 to form the air layer 13 between the second film 6b and the first film 6a. When the air layer 13 is formed between the first and second films 6a and 6b in this way, a barrier function that effectively blocks the additive that oozes out or elutes from the plug body 2 is effectively blocked by the air layer 13. It is exhibited and can be prevented from being mixed into the chemical solution. Therefore, the degree of freedom in selecting the material of the thermoplastic elastomer can be obtained. The number of the films 6 may be three or more.
[0023]
The choice of materials for the thermoplastic elastomer plug body 2 and the outer cap 1 also has a significant effect on the liquid leakage during the high-temperature sterilization process and the needle stick holding force after the sterilization.
A stopper formed by press-fitting a stopper body 2 having an outer diameter larger than the inner diameter of the outer cap 1 is welded to the mouth of a container such as a bottle or a bag, and is subjected to high-temperature and high-pressure sterilization (121). ° C for 30 minutes). Then, the outer cap 1 expands by losing the inflation pressure of the plug main body 2, and thereafter, the contraction of the plug main body 2 eliminates the dimensional difference between the outer diameter of the plug main body and the inner diameter of the outer cap, so that liquid leakage prevention and needle holding force are lost. . Therefore, it is necessary that the outer cap 1 be formed of a resin material having a bending elasticity that does not withstand the expansion pressure of the plug body 2 during high-temperature sterilization.
[0024]
Therefore, the present invention enables the prevention of liquid leakage and the securing of the needle holding force by defining the correlation between the elastomer hardness (JIS K6301) of the thermoplastic elastomer stopper body 2 and the bending elastic modulus (K7203) of the outer cap 1. . That is, the relationship between the elastomer hardness of the plug body 2 (use of Lavalon (registered trademark) manufactured by Mitsubishi Chemical Corporation as a styrene elastomer) and the flexural modulus of the outer cap 2 made of polypropylene is shown in the table of FIG. As described above, the flexural modulus (K7203) is preferably 300 Mpa or more, more preferably 350 to 700 Mpa. This will be clearly understood from the state of liquid leakage during high-temperature sterilization as shown in the table of FIG.
[0025]
When the outer cap 1 is a cap with a pull tab 5, the tearing strength of the top plate 3 becomes a problem. Normally, the tear strength of the pull tab 5 is desirably 3.5 kg (movable by 20 mm / l) or less so that women and girls can easily pull it apart. However, the thickness of the thin torn portion 4 of the molded product of the outer cap 1 with the pull tab 5 requires a minimum thickness of 0.35 mm for molding. If the thickness of the molded article is 0.35 mm or less, the resin does not cover the entire molded article during molding, resulting in molding failure. When the thickness of the tear-off portion 4 is 0.35 mm or more, and the bending elastic modulus (K7203) is the outer cap 1 with a pull tab made of a resin satisfying 350 Mpa, the tear-off strength becomes 6 kg or more, and the tear-off portion 4 becomes Is difficult to tear off.
[0026]
Therefore, in order to reduce the tear strength of the top plate 3 with the pull tab 5, the thickness of the tear portion 4 should be 0.1 to 0.25 mm in order to use a resin having a flexural modulus (K7203) of 350 MPa or more. preferable. In order to obtain the outer cap 1 with the pull tab 5 having the thickness of the tearing portion 4 of 0.1 to 0.25 mm, as shown in FIG. The outer cap 1 with the pull tab 5 is molded by compressing to 0.1 to 0.25 mm. At this time, by forming the entire top surface 14a of the protruding core 14 as a convex arc surface, the resin on the top surface side in the outer cap molding cavity is protruded below the outer periphery of the protruding core 14 when the protruding core 14 protrudes. Therefore, the outer cap 1 can be easily formed.
[0027]
Further, the inner surface of the top plate 3 with the pull tab 5 formed in this manner is formed as a concave arc surface 3a, and between the concave arc surface 3a and the concave arc surface 2a in the needle stick area of the plug body 2, A space 15 is formed as shown in FIG. This space 15 prevents the needle stick area of the thermoplastic elastomer stopper body 2 and the inner surface 3a of the top plate 3 with the pull tab 5 from being melted and integrated by the sterilization temperature even during high-temperature and high-pressure sterilization. It is useful to easily tear off the attached top plate 3 with a small pulling operation force.
[0028]
In molding the plug body 2 made of a thermoplastic elastomer, air bubbles are often involved in the plug body 2 due to the fluidity of the thick elastomer. If a needle is stabbed in the bubble, it may cause liquid leakage when the needle is pulled out. Therefore, as shown in FIG. 5, when the stopper ring 7 to which the thin film 6 is previously attached is held by the core 16 and the stopper body 2 is simultaneously molded in the cavity 20, as shown in FIG. If a gas vent hole 18 of 0.05 mm or less is provided between the outer periphery of the mold 7 and the mold 17 at a predetermined interval in the circumferential direction, only the air gas escapes, so that the thermoplastic elastomer plug body 2 without bubbles is used. Is obtained.
[0029]
According to the stopper of the present invention in which the thermoplastic elastomer stopper body 2 having an outer diameter larger than the inner diameter of the cap is press-fitted into the outer cap 7 with the pull tab obtained as described above, the resin needle after high-temperature sterilization is used. Sufficient needle holding force was obtained when the needle was pierced, and a good result was obtained in which no liquid leakage occurred even when the needle was pulled out after one hour or more.
[0030]
In the present invention, the outer cap 1 is not limited to the one having the pull tab as described above. As shown in FIG. 7, the outer cap 1 is provided with an easy peel film in which the top opening of the outer cap 1 is closed by the film 19 for keeping the outside airtight. The same applies to the outer cap. In this case, the film 19 for maintaining the external airtightness is welded to the outer cap 1 so as to cover the opening of the top surface thereof.
[0031]
【Example】
Example 1
The inner diameter of the outer cap 1 made of polypropylene is 23.18 mm, and the maximum outer diameter in the free state of the plug body 2 made of a styrene-based elastomer (Made by Mitsubishi Chemical Co., Ltd., Lavalon (registered trademark) T331C 28 hardness (JISK6301)) is 27. 2.0 mm, the outer peripheral wall thickness t1 of the needle stick area of the plug body 2 is 5.8 mm, the central wall thickness t2 is 3.8 mm, and the cross-sectional biconcave lens gradually becomes thinner from the outer peripheral part toward the central part. The plug body 2 having this size and shape was press-fitted into the outer cap 1 and the stopper ring 7 was fitted into the outer cap 1 for assembly.
[0032]
Comparative Example 1
It is the same as in Example 1 except that the inner diameter of the outer cap and the outer diameter of the plug body in the free state are both 23.18 mm.
[0033]
Comparative Example 2
It is the same as the case of Example 1 except that the whole plug body is formed to have a uniform thickness of 5.8 mm and a flat cross-section having upper and lower surfaces parallel to each other.
[0034]
(Test method)
A container of a bottle or a bag capable of storing a full capacity of 600 ml is filled with 500 ml of electrolyzed water (chemical solution), and the stoppers of Example 1, Comparative Example 1 and Comparative Example 2 are heat-welded to the mouth of the container, respectively. Measure the total weight. The containers in which the stoppers of Example 1, Comparative Example 1 and Comparative Example 2 were welded were sterilized with steam heat of 121 ° C. for 30 minutes, and a resin needle having a diameter of 4.5 was inserted into the designated portion 8 by a needle. After a lapse of time, the needle was withdrawn, pressurized at 4.5 Kg for 3 minutes, the total weight of the container was measured again, and the weight before and after the needle puncture was compared to determine the amount of liquid leakage. .
[0035]
(Test results)
The results of the comparative test are as shown in the table of FIG. On average, 0.003 g (one drop was 0.035 g) of liquid leaked from the stopper of the container subjected to the high-temperature sterilization treatment using the stopper of Example 1, and there was no leakage. That is, it was found that there was no problem in the liquid leakage test of the stopper of Example 1 even when sterilized by steam heat of 121 ° C. for 30 minutes.
On the other hand, the stopper of Comparative Example 1 had an average of 31.61 g, a maximum of 80.31 g, and a minimum of 3.0 g, which was extremely leaky. The stopper of Comparative Example 2 also had an average of 9.27 g and a maximum of 21. .26 g, the minimum was 1.03 g, and none of them could prevent liquid leakage.
[0036]
【The invention's effect】
According to the stopper of the container of the present invention, even after high-temperature and high-pressure sterilization, liquid leakage at the time of needle sticking or needle withdrawal can be prevented well, and even if the plug body is not so thick, needle stick resistance is reduced. There is an advantage that a sufficient needle stick holding force can be secured.
[Brief description of the drawings]
FIG. 1 is a sectional view of a stopper according to an embodiment of the present invention.
2 is a sectional view showing the outer cap and the plug body of the stopper of FIG. 1 in a separated state.
FIG. 3 is a sectional view of a plug body according to another embodiment.
FIG. 4 is a cross-sectional view showing a molding mode of an outer cap with a pull tab.
FIG. 5 is a partially cutaway sectional view of a mold showing a state in which a stopper ring is held in a molding mold of a plug body.
FIG. 6 is a sectional view taken along line AA in FIG.
FIG. 7 is a sectional view of a stopper according to another embodiment.
FIG. 8 is a table showing the correlation between the elastomer hardness of the thermoplastic elastomer stopper main body and the flexural modulus of the outer cap.
FIG. 9 is a table showing comparison results of a liquid leakage test of Example 1 and Comparative Examples 1 and 2.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 outer cap 2 stopper body 3 top plate 4 tear-off portion 5 pull tab 6 film 6a first film 6b second film 7 stopper ring 8 needle sticking designation portion 13 air space 15 space 19 film

Claims (12)

A stopper for a container, characterized in that a needle-pierceable plug body made of a thermoplastic elastomer and having an outer diameter larger than the inner diameter of the ring-shaped outer cap is press-fitted into the outer cap. The stopper for a container according to claim 1, wherein a ratio of an inner diameter of the outer cap to an outer diameter of the plug body is 1: 1.05 to 1.25. 3. The plug body according to claim 1, wherein the stopper main body is formed in a cross-sectional shape in which a thickness of an outer peripheral portion of the needle stick region is thicker than a thickness of a central portion and gradually becomes thinner from the outer peripheral portion toward a central portion. Stopper for container. A cross-sectional shape in which the ratio of the thickness of the outer peripheral portion to the thickness of the central portion of the needle stick region of the stopper body in the free state is 1: 0.3 to 0.95, and gradually becomes thinner from the outer peripheral portion toward the central portion. The stopper of the container according to claim 3, wherein the stopper is formed in the container. 2. A stopper ring is fitted on the lower surface side of the plug body in the outer cap, and one or more films having a thickness of 50 to 350 [mu] m are insert-molded or welded on the upper end surface of the opening of the stopper ring. A stopper for a container according to any one of claims 4 to 4. Two films having a thickness of 50 to 350 μm are insert-molded or welded to the upper end surface of the opening of the stopper ring, and one of the films is welded to the lower surface of the plug body and the second film is welded. 5. The stopper for a container according to claim 1, wherein an air layer is formed between the stopper and the container. The stopper for a container according to any one of claims 1 to 6, wherein a top surface opening of the outer cap is removably closed by a top plate with a pull tab. The container stopper according to any one of claims 1 to 6, wherein a top opening of the outer cap is covered with a film. The container according to any one of claims 1 to 8, wherein the thermoplastic elastomer is composed of at least one or more of a styrene-based elastomer, an olefin-based elastomer, and a polyester-based elastomer. Stopcock. The container stopper according to claim 7, wherein a space is formed between an inner surface of the top plate with the pull tab and an upper surface of the stopper body. The stopper for a container according to any one of claims 1 to 10, wherein an elastomer hardness (JIS K6301) of the stopper main body is 15 to 65, and a bending elastic modulus (K7203) of the outer cap is 300 MPa or more. The stopper for a container according to claim 9, wherein the container to which the stopper is attached is made of at least one, or two or more, of a styrene-based elastomer, an olefin-based elastomer, and a polyester-based elastomer.

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