JP2004338724A - Pull-top type cap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pull-top type cap which prevents a pull ring from easily breaking and being cut when it is pulled. <P>SOLUTION: The cap is made of a synthetic resin, and comprises a frame 1, a lid 2 joined to the frame 1 via a tear-off part 4, and at least a pull-top part 3 joined to the lid 2, and it is characterised in that the pull-top part 3 has the pull ring 3a whose entire circumference is made of a synthetic resin having no orientation due to resin flow, and the ratio (B/A) of the break strength (B) of the pull ring 3a to the break strength (A) of the tear-off part 4 is greater than 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a synthetic resin pull-top cap used as a cap for various containers such as a medical bottle such as an infusion bottle and a food bottle such as a beverage bottle.
[0002]
[Prior art]
BACKGROUND ART Conventionally, various types of synthetic resin caps have been provided as caps for containers such as medical bottles and food bottles. In particular, a cap provided with a pull top is provided to facilitate opening, and among them, a pull top cap applied to a medical bottle such as an infusion bottle is known (for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 6-45206 (Fig. 2)
[0004]
[Problems to be solved by the invention]
However, a ring-shaped pull top, that is, a cap made of a synthetic resin provided with a pull ring, often breaks at the pull ring portion when the pull ring is pulled open. In this case, it is attempted to open the pull ring by forcibly pulling the cut piece, but it is difficult to open. For example, in the case of food bottle caps such as seasonings and beverage bottles, it is well known. The same applies to a pull-top type cap applied to medical bottles such as infusion bottles, but particularly for container caps used for medical purposes, such a breakage or cutting phenomenon of the pull ring is also required in fields requiring particularly high safety and urgency. It is not preferable because there is.
[0005]
On the other hand, in order to prevent breakage or cutting of the pull ring, it is conceivable to increase the strength by changing the thickness or the material of the resin of the pull ring. desirable.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a pull-top cap in which the pull ring is easily broken and not cut even when the pull ring is pulled.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present invention provides a frame body, a lid joined to the frame via a tear-off portion, and at least the lid is joined to the lid. In a synthetic resin cap having a pull-top part,
The pull-top portion has a pull ring, the pull ring is made of a synthetic resin having no orientation due to resin flow over the entire circumference,
A pull-top cap is used, wherein the ratio (B / A) of the breaking strength (B) of the pull ring to the breaking strength (A) of the torn portion exceeds 1.
[0008]
The pull ring portion is usually formed by injection molding together with the cap frame. At that time, the molten resin (hot water) flowing in the process of injection molding flows through the annular cavity of the pull ring mold from both sides, and each end of the flow has a lower temperature drop than the flow portion behind it. This occurs, so to speak, with the film formed, flowing through the cavity, and both streams combine into one to form a ring. Therefore, while the formed pull ring has an orientation according to the flow of the resin, the flow is diffused while the junction (last filled portion) of the two resin flows includes the film portion. It becomes a very weak joint point in terms of strength, and distortion occurs. In the present invention, the cause of the breakage or breakage of the pull ring is that there are both a portion where the resin flow is oriented (a portion strong in the tensile direction) and a portion where the resin flow is diffused (a portion weak in the tensile direction). It has been found that the pull ring can be easily opened without breaking and cutting the pull ring by adopting the above configuration.
Thereby, even if the pull ring is pulled, the pull ring can be easily broken and a pull-top cap that is not cut can be obtained.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a sectional view showing an embodiment of a cap according to the present invention, and FIG. 2 is a perspective view of the same. In the figure, 1 is a frame, 2 is a lid joined to the edge of the opening 1a of the frame, and 3 is a pull-top joined to the lid.
[0010]
In this embodiment, the frame 1 and the lid 2 are made of synthetic resins of different materials, and the edge of the opening 1a of the frame 1 and the peripheral edge 2a of the lid 2 are formed. Is joined to the lower edge portion by pseudo fusion, thereby forming the tear-off portion 4. The pull-top portion 3 is composed of a pull ring 3a extending in a horizontal annular shape and a pull-top piece 3b extending in a column shape in a vertical direction, and an upper end of the pull-top piece 3b is joined to one side edge of the pull ring 3a. The lower end is joined to both the edge of the opening 1a of the frame body 1 and one side end of the lid body 2.
[0011]
Further, the pull ring of this embodiment is made of a synthetic resin having no orientation due to the resin flow over the entire circumference, and the breaking strength (B) of the pull ring with respect to the breaking strength (A) of the tear-off portion 4. Ratio (B / A) exceeds 1.
[0012]
Therefore, when the cap is opened using the cap of this embodiment, the pull ring is made of a synthetic resin having no orientation due to the resin flow over the entire circumference, and the breaking strength (A) of the tearing portion Since the ratio (B / A) of the breaking strength (B) of the pull ring to exceeds 1, even if a finger is inserted into the pull ring and the pull ring is pulled in the opening direction, the pull ring is not broken and cut, The lid 2 can be easily peeled off from the frame 1 at the tear-off portion 4 that has been pseudo-welded.
[0013]
FIG. 3 is a schematic sectional view showing another embodiment in which the cap according to the present invention is applied as a medical bottle cap. In FIG. 3, reference numeral 5 denotes a frame body, and 6 denotes a lid (sealing body) that seals an upper opening 7 inside the frame body 5. Reference numeral 8 denotes a pull-top portion attached to the lid 6. The pull-top portion 8 also includes a pull ring 8a extending in a horizontal annular shape and a pull-top piece 8b extending in a columnar shape, similarly to the cap shown in FIGS. 1 and 2, and the upper end of the pull-top piece 8b has the upper end of the pull ring 8a. The lower end of the pull-top piece 8b is joined to one end of the lid 6. The pull ring 8a is made of a synthetic resin having no orientation due to the resin flow over the entire circumference. Reference numeral 9 denotes a plug for needle piercing made of a polystyrene-based thermoplastic elastomer resin held inside the frame portion 5.
[0014]
In the cap of this embodiment, the frame portion 5 is made of a polyolefin-based thermoplastic resin, and the lid portion 6 and the pull-top portion 8 are made of a thermoplastic resin having a blend composition of a polyether-based thermoplastic elastomer resin and a polyester-based thermoplastic elastomer resin. It is composed of an elastomer resin. The lid 6 is fused to the peripheral edge of the upper opening 7 inside the frame 5 to form a tear-off portion 41, and the breaking strength of the fusion is 1.5. ７7 (N / 25 mm). In the cap of this embodiment, the lid 6 is also fused to the plug 9 for piercing the needle made of a polystyrene-based thermoplastic elastomer resin, and has a breaking strength (fusion strength) of 1. 0.5 to 7 (N / 25 mm). Then, the ratio (B / A) of the breaking strength (B) of the pull ring to the breaking strength (A) of the tearing portion exceeds 1, and further the pull ring to the breaking strength (C) of the plug 9. Also the ratio (B / C) of the breaking strength (B) exceeds 1.
[0015]
Further, as shown in FIG. 3, the cap of this embodiment has a structure in which the lid 6 is joined not only to the upper peripheral edge 5a of the frame 5 but also to the inner peripheral wall 5b following the step. is there.
[0016]
With the above configuration, while the lid 6 is integrally joined to the frame 5, the lid 6 can be easily attached to the upper peripheral edge of the frame 5 with little force by pulling the pull ring 8 a. From the portion 5a to the plug 9 made of a polystyrene-based thermoplastic elastomer resin via the inner peripheral wall 5b, it can be continuously separated from each portion. In the case of a cap for an infusion container, next, the infusion needle is pierced into the stopper 9 appearing in the upper opening 7 inside the frame 5 by the detached lid 6.
[0017]
Note that the present invention is not limited to the above embodiment. For example, in the above embodiment, the plug 9 for needle stick is made of a polystyrene-based thermoplastic elastomer resin, but may be made of natural or synthetic rubber. In the case of a plug made of a thermoplastic elastomer resin other than a polystyrene-based resin or a natural or synthetic rubber, a structure in which the lid 6 is not joined to and integrated with the plug 9 unlike the above embodiment is adopted. You can also. Further, instead of the joint structure between the lid portion 6 and the frame portion 5 as in the above-described embodiment, for example, as shown in FIG. It is also possible to form a joint structure in which the tearing portion 41 is formed by fusing while covering over the wall 5c. As shown in FIG. 5, the lid portion 62 has a joining structure in which the lid portion 62 is fused to the upper inner peripheral wall 5 of the frame body portion 5, and the tearing portion 42 is formed between the upper inner peripheral wall 5 and the side wall of the lid portion 62. It can also be constituted by a joint surface between them. In each of the above-described caps, the pull ring is made of a synthetic resin having no orientation due to resin flow over the entire circumference.
[0018]
In the present invention, in order to configure the pull ring with a synthetic resin having no orientation due to resin flow over the entire circumference, for example, a pull ring portion or a pull top portion or a lid portion with a pull top portion is formed by compression molding, and a frame portion or the like is formed. Can be molded by injection molding. Alternatively, the entire cap can be formed by compression molding.
[0019]
The breaking strength of the joint surface of the tear-off portion 41 of the pseudo welding and the joint surface of the lid body 6 and the plug 9 are the same as those of the synthetic resin pull ring having no orientation due to the resin flow over the entire circumference. Is preferably 1.5 to 7 (N / 25 mm), as described above. In addition, the tear-off portion is formed by pseudo welding, but the present invention is not limited to this, and a cutout portion is provided between the cap body and the pull-top instead. A configuration is acceptable. Furthermore, the above configuration can be applied as a cap for a medical bottle such as a medical bag. In this case, a configuration in which a plug made of rubber or an elastomer is fitted into the frame body for needle sticking can be adopted. Further, the present invention is not limited to medical use, and can be suitably used as a food bottle cap such as a beverage bottle cap.
[0020]
In addition, the breaking strength of the pull ring in the present invention means that the lid of the cap molded product is fixed, and the end of the pull ring is pulled at a speed of 200 mm / min from the open end of the pull top in a direction parallel to the lid. The measured value of the breaking strength (unit: N / 25 mm) of the pull ring is shown as the breaking strength (B) of the pull ring. In the present invention, the breaking strength of the tear-off portion and the breaking strength of the joint surface between the lid 6 and the plug 9 are determined by fixing the frame of the same cap molded product in a direction parallel to the lid. The pull ring is pulled from the open end side of the pull-top portion at a speed of 200 mm / min, and the measured value of the strength at which the tear portion is torn is shown as the breaking strength (A) of the tear portion. Similarly, the measured value of the strength at which the joint surface between the lid and the plug is torn off is shown as the breaking strength (C) of the torn off portion.
[0021]
【The invention's effect】
As described above, in the present invention, the pull-top portion has a pull ring, and the pull ring is made of a synthetic resin having no orientation due to the resin flow over the entire circumference, and the breaking strength (A) of the tear-off portion The pull-top cap is characterized in that the ratio (B / A) of the breaking strength (B) of the pull ring to exceeds 1, so that even if the pull ring is pulled, the pull ring is easily broken and is not cut. It can be a mold cap.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of a cap according to the present invention.
FIG. 2 is a perspective view of the same.
FIG. 3 is a schematic sectional view showing another embodiment in which the cap according to the present invention is applied as a medical bottle cap.
FIG. 4 is a schematic sectional view showing another embodiment of the medical bottle cap.
FIG. 5 is a schematic sectional view showing still another embodiment of the medical bottle cap.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Frame part 1a Opening hole 2 Lid part 2a Peripheral part 3 Pull-top part 3a Pull ring 3b Pull-top piece 4 Torn part 41 Torn part 5 Frame part 5a Upper peripheral part 5b Inner peripheral wall 5c Outer peripheral wall 6 Lid part 61 lid Body 62 Lid 7 Upper opening 8 Pull top 8a Pull ring 8b Pull top piece 9 Plug

Claims (7)

The frame portion, a lid portion joined to the frame portion via a tear-off portion, and a synthetic resin cap having at least a pull-top portion joined to the lid portion,
The pull-top portion has a pull ring, the pull ring is made of a synthetic resin having no orientation due to resin flow over the entire circumference,
A pull-top cap, wherein the ratio (B / A) of the breaking strength (B) of the pull ring to the breaking strength (A) of the torn portion exceeds 1. 2. The pull-top cap according to claim 1, wherein the tear-off portion is configured by joining the frame portion and the lid portion by pseudo welding. 3. The pull-top cap according to claim 1 or 2, wherein a breaking strength of a joining surface of the tearing portion is 1.5 to 7 (N / 25 mm). The pull-top cap according to claim 1, wherein the tear-off portion is formed by a notch provided between the cap body and the pull-top. The pull-top cap according to any one of claims 1 to 4, wherein rubber or an elastomer is fitted in the frame portion. A frame portion, a lid portion joined to the frame portion via a tear-off portion, a pull-top portion joined to at least the lid portion, and a lid portion provided in the frame portion. And a plug body made of an elastomer fused to each joint surface of the frame body portion,
The pull-top portion has a pull ring, the pull ring is made of a synthetic resin having no orientation due to resin flow over the entire circumference,
The ratio (B / A) of the breaking strength (B) of the pull ring to the breaking strength (A) of the torn portion exceeds 1, and
The medical treatment characterized in that the ratio (B / C) of the breaking strength (B) of the pull ring to the breaking strength (C) of the joining surface between the lid and the plug exceeds 1 (B / C). Pull-top cap for bottles. A food bottle cap comprising the cap according to claim 1.

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