JP6802631B2 - Liquid container - Google Patents

Description

The present invention relates to a liquid container such as an eye drop container, and particularly to a liquid container made of biomass plastic.

In recent years, the expansion of the range of use of biomass plastics has been attracting attention as a measure against global warming. Bioplastics has not yet been defined globally, but the Japan Bioplastics Association states that "it contains substances derived from renewable organic resources as raw materials and can be obtained by chemically or biologically synthesizing them. It is defined as a polymer material having a molecular weight (Mn) of 1000 or more (excluding scientifically unmodified non-thermoplastic natural organic polymer materials).

Biomass, which is a raw material for such biomass plastics, is mainly saccharides extracted from corn, sugar cane, etc., which can obtain abundant and uniform quality. When biomass is burned, carbon dioxide is generated, but since the carbon is absorbed by plants from what was originally in the atmosphere, the carbon dioxide in the atmosphere does not increase even if the biomass burns. .. Therefore, converting plastic products from fossil fuel-derived products to biomass-derived products is considered to be useful as a measure against global warming.

However, at present, the production of plant-derived biomass polyethylene and biomass polypropylene is limited even in the world. Braskem S.A., the largest petrochemical manufacturer in Latin America, produces about 3 million tonnes of fossil fuel-derived polyethylene, while plant-derived polyethylene is only about 200,000 tonnes.

Due to the low production volume, the choice of grades of plant-derived polyethylene available on the market is limited, and it is often not possible to obtain plant-derived polyethylene with the same performance as fossil fuel-derived polyethylene.

The applicant of the present application has been developing and manufacturing an eye drop container for some time, and the eye drop container is required to have a high level of air barrier property and water vapor barrier property in order to maintain the medicinal effect, and is sealed at the time of cap sealing. Since various physical properties such as sex, transparency for visual confirmation of internal solution, and good squeeze property for administration of internal solution are required at a high level, it is conventionally derived from fossil fuel that is relatively resistant to stress. I used plastic.

The documents known to the applicant and the agent of the present application before the application of the present application are shown below.

Japanese Unexamined Patent Publication No. 11-169230 Jitsukaisho 62-42548 JP-A-2015-16871 Japanese Unexamined Patent Publication No. 2012-11591

Patent Document 1 is a container for a volatile liquid agent having an alcohol content of 60% or more, such as a hair restorer, which includes a container body having a mouth portion and an inner plug which is internally fitted in the mouth portion and has a discharge nozzle. It is equipped with a cap that is detachably screwed to the outer circumference of the mouth. The cap has a convex portion (12) that fits into the opening at the tip of the nozzle when the cap is screwed into the mouth, and a liquid that abuts on the upper surface of the flange of the inner plug to watertightly seal the container mouth. A tubular contact ring (13) for preventing leakage is provided. This contact ring is provided to prevent liquid leakage when the container body falls down and to prevent evaporation of volatile components such as alcohol in the internal liquid to the outside of the container by pressing the flange part watertightly. Has been done. That is, in the container disclosed in Patent Document 1, liquid leakage is prevented by contact between the contact ring and the flange portion, and the convex portion (12) is a nozzle for opening a slit (8) at the tip of the nozzle. It is designed to fit into.

Patent Document 2 discloses a liquid container in which a rubber inner plug is internally fitted in the mouth of the container body and a cap is screwed on the outer periphery. The inner plug is provided with a nozzle (transparent thin tube) made of a glass tube or the like, and the nozzle is elastically held by the inner plug. Therefore, when the cap is screwed so as to push the nozzle tip by the convex portion (16) provided on the top surface of the cap, the repulsive force of the rubber presses the nozzle tip and the convex portion of the cap to prevent liquid leakage. It has become like. Further, the inner plug is provided with a flange portion, and the cap abuts on the upper surface of the flange portion to prevent liquid leakage in this portion.

Patent Document 3 discloses an eye drop container including a container body, an inner plug attached to the mouth of the container body, and a cap detachably attached to the mouth. The inner plug includes a nozzle portion and a flange portion. The cap has a plug portion that closes the tip opening of the nozzle portion and a pressing portion that presses the flange portion to bring it into pressure contact with the upper end surface of the mouth portion. The container body is filled with a liquid agent to form an inner plug and an inner plug. When the cap is attached to the mouth and subjected to high-pressure steam sterilization, the flange is adhered to the upper end surface of the mouth.

Patent Document 4 discloses an eye drop container using the conventional fossil fuel-derived plastic of the applicant of the present application, in which an inner plug having a nozzle hole is internally fitted in the mouth of the container body and on the outer periphery of the mouth. The cap is screwed on. The cap includes a tubular portion screwed into the mouth portion and a conical portion integrally provided at the upper end portion of the tubular portion, and is fitted into a nozzle hole on the lower surface of the top of the conical portion. A convex portion is provided. The inner plug has a collar, and in the structure described in the drawing, the cap is in a state where the tip opening of the nozzle hole is hermetically sealed by the convex portion of the cap by tightening the cap with a predetermined tightening torque. It is far away from the collar. This is because, in the case of the conventional fossil fuel-derived plastic, the convex portion is strongly pressed against the tip of the nozzle hole in order to give priority to ensuring the liquidtightness of the nozzle hole. Although it is stated that the cap may be brought into close contact with the upper surface of the flange portion (paragraph number 0029), the elastic displacement of the nozzle portion is not considered at the time of filing of Patent Document 4, and the convex portion is the nozzle hole. It is described that the cap may be brought into close contact with the upper surface of the flange portion at the same time as being brought into close contact with the tip portion.

The applicant of the present application is conducting various tests and studies to convert a liquid container such as an instillation container into a bioplastic plastic, and instilled using biomass polyethylene with the structure manufactured using fossil fuel-derived polyethylene. A trial production of the inner plug and cap of the container was performed, and after tightening the cap with a predetermined tightening torque, a long-term storage test was conducted. A stress crack occurred due to the destruction.

An object of the present invention is to provide a biomass plastic liquid container in which the above stress cracks are improved while the functionality as a liquid container is equivalent to that of a conventional fossil fuel-derived polyethylene.

The present invention has taken the following technical measures in order to solve the above problems.

That is, the present invention includes a container body having a mouth portion, an inner plug attached to the mouth portion, and a cap detachably screwed to the mouth portion, and the inner plug is an opening of the mouth portion. A flange portion that engages with the end face and a nozzle that extends toward the tip side along the axial direction of the mouth portion are provided, the nozzle is provided with a liquid flow hole at the axial center portion thereof, and the cap is attached to the mouth portion. In a liquid container provided with a convex portion that abuts on the tip opening of the liquid flow hole of the nozzle in a completely screwed state and seals the tip opening in a liquidtight manner.
The cap further includes an engaging portion that engages the flange portion from the tip side in a state of being completely screwed to the mouth portion.
When the cap is screwed to the mouth portion and the convex portion is in an incompletely screwed state in which the convex portion is just in contact with the tip opening portion, a predetermined clearance is provided between the engaging portion and the flange portion. The engaging portion is formed so as to occur.
The state in which the cap is completely screwed to the mouth portion is a state in which the engaging portion is pressed against the flange portion by further tightening the cap from the incompletely screwed state. It is characterized in that, by being pressed toward the proximal end side by the convex portion, an elastic displacement of a displacement amount corresponding to the clearance to the proximal end side is generated in the tip opening of the nozzle. ..

According to the liquid container of the present invention, even if the cap is tightened with a predetermined tightening torque for making the cap completely screwed, after the incompletely screwed state, the pressing force of the engaging portion with respect to the flange portion is applied. It mainly bears the stress caused by the additional tightening due to the rise, and the pressing force of the convex portion of the cap with respect to the tip of the nozzle hardly rises after the incompletely screwed state. Therefore, the stress generated at the nozzle tip can be adjusted by the amount of clearance, and the stress generated at the nozzle tip in the fully screwed state is suppressed within the allowable stress range in the biomass plastic, so that the stress crack at the nozzle tip during long-term storage Occurrence can be prevented.

The container disclosed in Patent Document 2 has a structure in which a rubber nozzle holds a glass nozzle, and the molding accuracy of the rubber product is not as high as that of the plastic product, and the rubber inner plug is used. The cap is based on the technical idea that the tip of the nozzle and the flange are engaged at almost the same time because the elastic repulsive force is to be generated by the relatively large deformation of the above. The technical idea is different from the present invention in which the clearance is strictly designed to cause elastic deformation of the nozzle within the allowable stress range in the biomass plastic having a displacement amount corresponding to the clearance. That is, in the container disclosed in Patent Document 2, as the tightening torque of the cap increases, the amount of deformation of the rubber inner plug increases and the stress at the tip of the nozzle increases.

In the liquid container of the present invention, the cap has a top portion whose inner surface is curved like a dome, and the convex portion is provided at the central portion of the top portion, whereby the external force acting on the convex portion causes the cap. The stress concentration around the convex portion may be relaxed. According to this, it is possible to relax the stress concentration around the convex portion of the cap and prevent stress cracks from occurring in the central portion and the corner portion of the top surface of the cap during long-term storage in a completely screwed state.

Further, the inner plug and / or the cap may be made of biomass plastic. If the both the inner plug and the cap are made of the biomass plastic by configuring biomass plastic relatively rigid the caps, it is possible to ensure the stability of the sealing performance of the operation feeling and the nozzle end opening portion of the cap ..

The clearance can be designed according to the dimensions of each part of the inner plug and the cap, but for example, in the case of an eye drop container of a general size, it can be 0.1 mm or more and less than 0.3 mm. In the case of a relatively large container, the clearance may be 0.3 mm or more, and may exceed 1 mm as long as the above-mentioned action of the present invention occurs.

A state in which the cap is completely screwed to the mouth by filling the container body of the liquid container of the present invention with a liquid and screwing a cap to the mouth of the container with a predetermined tightening torque. According to the storage method of the liquid container, which is characterized by storing in, the internal stress generated in the inner plug and / or the cap is reduced even if the tightening torque is large, and the inner plug and / or the cap is made of biomass plastic. However, it is possible to prevent stress cracks from occurring during long-term storage.

According to the present invention, the sealing performance and operability equivalent to those made of conventional fossil fuel-derived polyethylene can be obtained, but even when the inner plug and / or cap is made of biomass plastic, it can be stored for a long period of time. It is possible to prevent the occurrence of stress cracks.

It is a vertical sectional view of the cap of the eye drop container which concerns on one Embodiment of this invention in the state of being completely screwed. It is a vertical cross-sectional view of the cap incompletely screwed state of the same eye drop container. It is a stress phase diagram in the case of a clearance of 0.1 mm and a tightening torque of 50 N · cm. It is a stress phase diagram in the case of a clearance of 0.2 mm and a tightening torque of 50 N · cm. It is a stress phase diagram in the case of a clearance of 0.3 mm and a tightening torque of 50 N · cm. It is a stress phase diagram of the comparative example. It is a vertical sectional view of the eye drop container which concerns on another embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an eye drop container as a liquid container according to an embodiment of the present invention. The eye drop container includes a bottle 2 (container body) having a mouth portion 1 at the upper end portion, an inner plug 3 fitted into the mouth portion 1 from above, and a cap 4 detachably screwed to the mouth portion 1. I have. A male screw portion is formed on the outer periphery of the mouth portion 1.

The inner plug 3 is made of plant-derived biomass polyethylene (for example, made of low-density polyethylene), and engages with the tubular base portion 3a internally fitted in the mouth portion 1 and the open end surface (upper surface of the mouth) of the mouth portion 1. It is integrally molded with a flange portion 3b and a tubular nozzle portion 3c having a liquid flow hole in the axial center portion. The nozzle portion 3c extends toward the tip end side along the axial direction of the mouth portion 1. The liquid flow hole of the nozzle portion 3c is gradually increased in diameter toward the tip side, and the hole diameter at the tip opening of the nozzle portion 3c is the largest. The outer peripheral edge of the tip of the nozzle portion 3c is formed on a gently curved surface. Further, the central portion of the shaft of the nozzle portion 3c is integrally connected to the flange portion 3b via the connecting portion 3d, and the connecting portion 3d projects toward the tip side inward in the radial direction like a diaphragm. Has a structure that has been made.

The cap 4 is made of plant-derived biomass polyethylene (for example, made of high-density polyethylene) that is harder than the biomass polyethylene constituting the inner plug 3, and has a tubular portion 4a that covers the outer periphery of the mouth portion 1 and the tubular portion. It is composed of a dome-shaped portion 4b (top) integrally provided at the upper end portion of 4a. On the inner peripheral surface of the tubular portion 4a, a female screw portion that is screwed into the male screw portion of the mouth portion 1 is provided. Inside the connecting portion between the tubular portion 4a and the dome-shaped portion 4b, an engaging step portion 4c (engaging portion) having an engaging surface facing the upper surface of the flange portion 3b of the inner plug 4 is provided. The engaging step portion 4c is pressed against the flange portion 3b in a completely screwed state in which the cap 4 is tightened to the mouth portion 1 with a predetermined tightening torque.

The inner surface of the dome-shaped portion 4b is curved like a dome, and in the present invention, the outer peripheral surface shape does not have to be dome-shaped. Further, at the center of the inner surface of the uppermost portion of the dome-shaped portion 4b, a convex portion 4d is provided which abuts on the tip opening of the nozzle portion 3c in a completely screwed state and seals the tip opening in a liquidtight manner. There is. The convex portion 4d is formed by a hill-shaped curved portion larger than the tip opening diameter of the liquid flow hole, is not fitted inside the liquid flow hole, and covers the entire circumference of the tip opening edge of the liquid flow hole. The tip opening is hermetically sealed by pressure contact.

As shown in FIG. 2, the engaging step portion 4c of the cap 4 is incomplete in which the convex portion 4d just abuts on the tip opening of the nozzle portion 3c in the process of screwing the cap 4 to the mouth portion 1. In the screwed state, the positional relationship with respect to the convex portion 4d is set so that a predetermined clearance d is generated between the engaging step portion 4c and the flange portion 3b.

According to the test research by the inventors of the present application, the amount of the clearance d is 0.1 mm or more and 0 in the case of an eye drop container having a general size in which the protrusion amount of the nozzle 3c from the flange 3b to the tip side is about several mm. It is preferably less than .3 mm, more preferably 0.15 mm or more and less than 0.25 mm.

The cap completely screwed state shown in FIG. 1 is a state in which the engaging step portion 4c is pressed against the flange portion 3b by further tightening the cap 4 with a predetermined tightening torque from the incompletely screwed state shown in FIG. Is. Further, the cap completely screwed state is a state in which the tip opening of the nozzle portion 3c is elastically displaced toward the proximal end side by being pressed toward the proximal end side by the convex portion 4d, and the elastic displacement amount is substantially. Is equal to the above clearance d. Preferably, even if the cap is tightened with less than a predetermined lower limit torque (for example, 20 Ncm), the engaging step portion 4c is not pressed against the flange portion 3b, and when the cap is tightened with this lower limit torque, the engaging step is tightened. The portion 4c is just in close contact with the flange portion 3b, and further tightening with a tightening torque exceeding the lower limit torque from this state brings the engaging step portion 4c into a state of being in pressure contact with the flange portion 3b.

3 to 5 show stress analysis simulations when the cap is tightened with a tightening torque of 50 N · cm and the clearance d is set to 0.1 mm, 0.2 mm, and 0.3 mm, respectively. The result is shown. Further, FIG. 6 shows the same analysis result when the engaging step portion is not provided for comparison. In the simulation, the structure of the threaded portion is simplified, and the load generated in the tubular portion 4a by the tightening torque of 50 N · cm is applied downward to the tubular portion 4a of the cap 4 and is applied to the mouth portion 1. As the reaction force, an upward load is applied.

As is clear from FIG. 6, when the engaging step portion is not provided, almost all of the tightening torque acts on the nozzle tip, the load acting on the nozzle portion exceeds 100 N, and the maximum stress value is 27.0 MPa. It became.

On the other hand, in the eye drop container according to the present embodiment in which the clearance d is set to 0.1 mm, as shown in FIG. 3, the load of the nozzle portion is reduced to 25 N and the maximum stress value (in this case, the tubular base portion 3a) is reduced. The stress in the vicinity of the connection between the flange and the flange 3b) was also suppressed to 17.9 MPa. However, in this case, the contact pressure between the tip of the nozzle portion 3c and the convex portion 4d of the cap is slightly insufficient, and there is a concern that the liquid agent may leak from the nozzle tip opening depending on the permeability and viscosity of the liquid agent.

Further, even in the instillation container according to the present embodiment in which the clearance d is set to 0.2 mm, excessive stress concentration is not observed in any of the cap 4 and the inner plug 3 as shown in FIG. 4, and the nozzle portion load is not observed. Was 50 N, and the maximum stress value (in this case, the stress near the connection portion between the tubular base portion 3a and the flange portion 3b) was 14.7 MPa. In this case, the contact pressure between the tip of the nozzle portion 3c and the convex portion 4d of the cap is also necessary and sufficient, and the sealing property of the nozzle tip opening is also good.

Further, even when the clearance d is set to 0.3 mm, as shown in FIG. 5, excessive stress concentration is observed as in the case where the engaging step portion is not provided in any of the cap 4 and the inner plug 3. However, the nozzle load increased to 72 N, and in this case, the maximum stress was generated at the tip of the nozzle 3c, and the maximum stress value also increased to 20.9 MPa.

The present invention is not limited to the above embodiment, and the design can be changed as appropriate. For example, the shape or structure of the cap and the engaging portion may be appropriate, and as shown in FIG. 7, the cap 4 has a substantially cylindrical structure as a whole and has a double outer cylinder portion and a screw cylinder portion. It has a tubular structure, and an engaging tubular portion 4e (engaging portion) is projected from the top plate portion inside the screw tubular portion, and the engaging tubular portion 4e is the upper stage of the flange portion 3b having a two-stage structure. May be engaged from above. Further, in order to alleviate the stress concentration at the joint portion between the screw cylinder portion and the top plate portion, the inner surface of the connection portion between the top plate portion and the screw cylinder portion is formed into a dome shape inside the screw cylinder portion as shown in FIG. Can be curved.

Further, as a molding material for the cap and / or the inner plug, an appropriate plant-derived biomass plastic can be used.

Claims (6)

A flange having a container body having a mouth portion, an inner plug attached to the mouth portion, and a cap detachably screwed to the mouth portion, and the inner plug engages with an open end surface of the mouth portion. A portion and a nozzle extending toward the tip side along the axial direction of the mouth portion are provided, the nozzle is provided with a liquid flow hole at the axial center portion thereof, and the cap is completely screwed to the mouth portion. In a liquid container provided with a convex portion that abuts on the tip opening of the liquid flow hole of the nozzle in a state and seals the tip opening in a liquidtight manner.
The cap further includes an engaging portion that engages the flange portion from the tip side in a state of being completely screwed to the mouth portion.
When the cap is screwed to the mouth portion and the convex portion is in an incompletely screwed state in which the convex portion is just in contact with the tip opening portion, a predetermined clearance is provided between the engaging portion and the flange portion. The engaging portion is formed so as to occur.
The state in which the cap is completely screwed to the mouth portion is a state in which the engaging portion is pressed against the flange portion by further tightening the cap from the incompletely screwed state. By being pressed toward the proximal end by the convex portion, the tip opening of the nozzle is elastically displaced toward the proximal end by an amount of displacement corresponding to the clearance.
The convex portion is formed by a hill-shaped curved portion larger than the tip opening diameter of the liquid flow hole, and is not fitted inside the liquid flow hole, but is entirely on the tip opening edge of the liquid flow hole. der which seal the tip opening in a liquid-tight manner by pressing the circumferential is,
The inner plug is made of biomass plastic, and the amount of the clearance is adjusted so as to suppress the stress generated in the tip opening of the nozzle in the completely screwed state within the allowable stress range in the biomass plastic. Liquid container. The cap has a top portion whose inner surface is curved in a dome shape, and the convex portion is provided at the central portion of the top portion, whereby stress concentration around the convex portion due to an external force acting on the convex portion is relaxed. The liquid container according to claim 1, wherein the liquid container is made. The liquid container according to claim 1, wherein the cap is made of biomass plastic. The liquid container according to claim 3, wherein the cap is made of a biomass plastic that is harder than the inner plug. The liquid container according to any one of claims 1 to 4, wherein the clearance is 0.1 mm or more and less than 0.3 mm. The cap is attached to the mouth of the container by filling the container body of the liquid container according to any one of claims 1 to 5 with a liquid and screwing a cap to the mouth of the container with a predetermined tightening torque. A method of storing a liquid container, which comprises storing it in a completely screwed state.

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