JP2017145039A - Liquid container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biomass plastic liquid container which has the same functionality as that of a conventional fossil fuel-derived polyethylene liquid container, but improves a stress crack problem.SOLUTION: An eyedropper with a cap 4 and/or an inner plug 3 with a nozzle made of biomass plastic comprises an engagement part 4c engaged with the inner plug 3 from a tip end side in the state of being screwed to a mouth 1 in the cap 4. The engagement part 4c is formed in advance in such a manner that a prescribed clearance d is generated between the engagement part 4c and the inner plug 3 when a protrusion 4d of the cap 4 just comes into contact with a nozzle tip opening of the inner plug 3 as the cap 4 is screwed on the mouth 1. This prevents an excessive load on the nozzle of the inner plug 3 from being generated because the engagement part 4c comes into contact with the inner plug 3 when the cap 4 is completely screwed on the mouth 1.SELECTED DRAWING: Figure 1

Description

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

  In recent years, the expansion of the range of use of biomass plastics has attracted attention as a measure against global warming. Biomass plastics has not yet been defined globally, but the Japan Bioplastics Association has stated that it can be obtained by chemical or biological synthesis, including materials derived from organic resources that can be recycled as raw materials. Polymer materials having a molecular weight (Mn) of 1000 or more (excluding scientifically unmodified non-thermoplastic natural organic polymer materials) ”.

  The biomass used as a raw material for such biomass plastic is mainly saccharides extracted from corn, sugarcane, etc., which can be obtained with abundant and uniform quality. When biomass is burned, carbon dioxide is generated, but since the carbon was originally absorbed into the body by the plant, carbon dioxide in the atmosphere does not increase even when biomass is burned . Therefore, converting plastic products from fossil fuel-derived ones to biomass-derived ones is considered useful for global warming countermeasures.

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

  Because of the low production volume, the options for the grade of plant-derived polyethylene supplied to the market are limited, and it is often impossible to obtain plant-derived polyethylene having the same performance as fossil fuel-derived polyethylene.

  The applicant of the present application has been developing and manufacturing eye drop containers for a long time, and eye drop containers are required to have a high level of air barrier and water vapor barrier properties in order to maintain their medicinal properties, and are sealed when the cap is sealed. Because it is required to have various physical properties at a high level, such as properties, transparency for visual confirmation of internal solution, and good squeeze property for administration of internal solution, it has been derived from fossil fuels that are relatively resistant to stress. Plastic was used.

  The following documents are known to the applicant and the representative before filing this application.

JP 11-169230 A Japanese Utility Model Publication No. 62-42548 JP 2015-166871 A JP 2012-110591 A

  Patent Document 1 is a container for a volatile liquid agent having an alcohol content of 60% or more such as a hair restorer, a container main body having a mouth portion, an inner plug fitted in the mouth portion and having a discharge nozzle; And a cap that is detachably screwed to the outer periphery of the mouth portion. The cap includes a convex portion (12) that fits into the opening at the tip of the nozzle when the cap is screwed into the mouth portion, and a liquid that abuts against the upper surface of the flange portion of the inner plug and seals the container mouth watertight. A cylindrical contact ring (13) for preventing leakage is provided. This contact ring is provided in order to prevent liquid leakage when the container body falls and to prevent evaporation of volatile components such as alcohol in the internal solution to the outside of the container by pressing the flange part in a watertight manner. It has been. 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 the slit (8) at the tip of the nozzle. It is made to fit in.

  Patent Document 2 discloses a liquid container in which a rubber inner plug is fitted into the mouth of a container body and a cap is screwed to the outer periphery. The inner plug is provided with a nozzle (transparent thin tube) made of a glass tube or the like, and this nozzle is elastically held by the inner plug. Therefore, when the cap is screwed so that the tip of the nozzle is pushed in by the convex portion (16) provided on the top surface of the cap, the nozzle tip and the convex portion of the cap are pressed by the repulsive force of the rubber, thereby preventing liquid leakage. It is like that. Further, the inner plug is provided with a flange portion, and the cap is brought into contact with the upper surface of the flange portion to prevent liquid leakage at this portion.

  Patent Document 3 discloses an ophthalmic container including a container main body, an inner stopper attached to the mouth portion of the container main body, and a cap detachably attached to the mouth portion. The inner plug includes a nozzle portion and a flange portion. The cap has a plug part that closes the tip opening of the nozzle part, and a pressing part that presses the flange part and presses against the upper end surface of the mouth part, fills the container body with a liquid agent, When the cap is attached to the mouth portion and subjected to high-pressure steam sterilization, the flange portion is bonded to the upper end surface of the mouth portion.

  Patent Document 4 discloses an eye drop container using a conventional fossil fuel-derived plastic of the applicant of the present application, and an inner plug having a nozzle hole is fitted in the mouth portion of the container body, and the mouth portion has an outer periphery. The cap is screwed. The cap includes a cylindrical portion that is screwed into the mouth portion, and a conical portion that is integrally provided on the upper end portion of the cylindrical portion, and is fitted into the nozzle hole on the lower surface of the top of the conical portion. Protrusions are provided. In the structure shown in the drawing, the cap has a collar portion, and the cap opening is tightened with a predetermined tightening torque so that the tip opening of the nozzle hole is liquid-tightly sealed by the convex portion of the cap. It is greatly separated from the buttocks. This is because, in the case of a conventional fossil fuel-derived plastic, priority is given to ensuring liquid-tightness of the nozzle hole so that the convex portion is strongly pressed against the nozzle hole tip. Although it is described that the cap may be brought into close contact with the upper surface of the collar 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 a statement that the cap may be in close contact with the upper surface of the collar portion simultaneously with the close contact with the tip portion.

  The applicant of the present application is conducting various research studies to convert liquid containers such as eye drops containers to those made of biomass plastic. When a long-term storage test was conducted after the cap and cap of the container were prototyped and the cap was tightened with a predetermined tightening torque, the nozzle tip of the cap and / or the center and / or corner of the top surface of the cap were brittle. Stress cracks due to destruction occurred.

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

  In order to solve the above problems, the present invention has taken the following technical means.

That is, the present invention includes a container main body having a mouth portion, an inner stopper attached to the mouth portion, and a cap that is detachably screwed to the mouth portion, and the inner stopper is an opening of the mouth portion. A flange portion that engages with the end surface; and a nozzle that extends toward the distal end side along the axial direction of the mouth portion, the nozzle having a liquid flow hole in an axial center portion thereof, and the cap at the mouth portion. In a liquid container provided with a convex portion that comes into contact with the tip opening of the liquid circulation hole of the nozzle in a completely screwed state and seals the tip opening in a liquid-tight manner,
The cap further includes an engagement portion that is engaged with the flange portion from the front end side in a state where the cap is completely screwed to the mouth portion,
When the cap is screwed into the mouth portion, a predetermined clearance is provided between the engaging portion and the flange portion when the convex portion is in an incompletely screwed state in which it just contacts the tip opening. The engaging portion is formed to produce,
The state in which the cap is completely screwed into the mouth portion is a state in which the engaging portion is pressed against the flange portion by additionally tightening the cap from the incompletely screwed state, By being pressed toward the base end side by the convex portion, an elastic displacement toward the base end side of a displacement amount corresponding to the clearance has occurred in the tip opening portion of the nozzle. .

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

  The container disclosed in Patent Document 2 has a configuration in which a glass nozzle is held by a rubber inner plug, and the molding accuracy of the rubber product is not as high as that of a plastic product. The cap is based on the technical idea of engaging the nozzle tip portion and the flange portion almost simultaneously. The technical idea is different from the present invention in which the clearance is strictly designed and the nozzle causes elastic deformation within the allowable stress range in the biomass plastic having a displacement 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 stopper increases and the stress at the nozzle tip increases.

  In the liquid container of the present invention, the cap has a top portion whose inner surface is curved in a dome shape, and the convex portion is provided at a 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 alleviated. According to this, stress concentration around the convex portion of the cap can be relaxed, and stress cracks can be prevented from occurring in the central portion and corner portion of the top surface of the cap during long-term storage in the completely screwed state.

  Further, the inner plug and / or the cap can be made of biomass plastic. When both the inner plug and the cap are made of biomass plastic, the cap may be made of biomass plastic having a smaller elastic modulus than the inner plug. According to this, by configuring the cap with a relatively hard biomass plastic, it is possible to ensure the stability of the operational feeling of the cap and the sealing performance of the nozzle tip opening.

  The clearance can be designed according to the dimensions of each part of the inner plug and the cap. For example, in the case of a general-sized eye drop container, the clearance 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 if the above-described action of the present invention occurs.

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

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

It is a longitudinal cross-sectional view of the ophthalmic container according to an embodiment of the present invention in a fully screwed state of the cap. It is a longitudinal cross-sectional view of a cap eyelet container incompletely screwed state. It is a stress state figure in case of clearance 0.1mm and fastening torque 50N * cm. It is a stress state figure in case of clearance 0.2mm and fastening torque 50N * cm. It is a stress state figure in case of clearance 0.3mm and fastening torque 50N * cm. It is a stress state figure of a comparative example. It is a longitudinal cross-sectional view of the eye drop container which concerns on another embodiment of this invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the 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 main body) having a mouth portion 1 at an upper end portion, an inner stopper 3 fitted into the mouth portion 1 from above, and a cap 4 detachably screwed into 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 a cylindrical base portion 3 a fitted in the mouth portion 1 and an opening end surface (mouth upper surface) of the mouth portion 1. The flange part 3b and the nozzle part 3c comprised in the tubular shape which has a liquid circulation hole in an axial center part are integrally formed. The nozzle part 3c is extended toward the front end side along the axial direction of the mouth part 1. The liquid circulation hole of the nozzle part 3c is gradually increased in diameter toward the tip side, and the hole diameter at the tip opening of the nozzle part 3c is the largest. The outer peripheral edge of the tip of the nozzle portion 3c is formed with a gentle curved surface. In addition, the central portion of the nozzle portion 3c is integrally connected to the flange portion 3b via the connecting portion 3d, and the connecting portion 3d protrudes toward the tip side as it goes radially inward like a diaphragm. Has a structured.

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

  The inner surface of the dome-shaped portion 4b is curved in a dome shape, and the outer peripheral surface shape may not be a dome shape in the present invention. In addition, a convex portion 4d is provided in the center of the innermost surface of the topmost portion of the dome-shaped portion 4b so as to contact the tip opening of the nozzle portion 3c in a completely screwed state and seal the tip opening in a liquid-tight manner. Yes. This convex portion 4d is formed by a hill-like curved portion larger than the tip opening diameter of the liquid circulation hole, and is not fitted in the liquid circulation hole, and extends around the entire circumference of the tip opening edge of the liquid circulation hole. The tip opening is sealed in a liquid-tight manner by pressure contact.

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

  The amount of the clearance d is 0.1 mm or more in the case of an eyedrop container having a general size in which the amount of protrusion of the nozzle 3 c from the flange 3 b to the tip side is about several millimeters, according to a test study by the inventors. Is preferably less than 3 mm, more preferably 0.15 mm or more and less than 0.25 mm.

  The fully screwed state of the cap shown in FIG. 1 is a state in which the engaging step 4c is pressed against the flange 3b by further tightening the cap 4 with a predetermined tightening torque from the incompletely screwed state shown in FIG. It is. Further, the fully screwed state of the cap is a state where the distal end 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 equal to Is equal to the clearance d. Preferably, even when the cap is tightened at a torque lower than a predetermined lower limit torque (for example, 20 N · cm), the engagement step portion 4c is not pressed against the flange portion 3b. The part 4c is brought into close contact with the flange part 3b, and the engagement step part 4c is brought into pressure contact with the flange part 3b by further tightening with a tightening torque exceeding the lower limit torque from this state.

  FIGS. 3 to 5 show respective 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. Results are shown. Further, FIG. 6 shows a similar analysis result in the case where the engagement step portion is not provided for comparison. In the simulation, the structure of the screw portion is simplified, the load generated in the cylindrical portion 4a by the tightening torque 50 N · cm is applied to the cylindrical portion 4a of the cap 4 downward, and the mouth portion 1 is applied. As a reaction force, an upward load is applied.

  As is apparent from FIG. 6, when the engagement 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 on the nozzle portion decreases to 25 N and the maximum stress value (in this case, the cylindrical base 3a). The stress in the vicinity of the connecting portion between the flange portion 3b and the flange portion 3b) was also suppressed to 17.9 MPa. However, in this case, the contact pressure between the tip portion of the nozzle portion 3c and the convex portion 4d of the cap is slightly insufficient, and the liquid agent leaks from the nozzle tip opening depending on the permeability and viscosity of the liquid agent.

  Further, even in the eye drop container according to the present embodiment in which the clearance d is set to 0.2 mm, no excessive stress concentration is observed in any part of the cap 4 and the inner plug 3 as shown in FIG. Was 50 N, and the maximum stress value (in this case, the stress in the vicinity of the connecting portion between the cylindrical 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 performance of the nozzle tip opening is good.

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

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

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

Claims (8)

A container body having a mouth portion, an inner stopper attached to the mouth portion, and a cap that is detachably screwed to the mouth portion, wherein the inner stopper engages with an opening end surface of the mouth portion. And a nozzle extending toward the tip side along the axial direction of the mouth, the nozzle having a liquid flow hole in its axial center, and the cap being completely screwed into the mouth In a liquid container comprising a convex portion that contacts the tip opening of the liquid circulation hole of the nozzle in a state and seals the tip opening in a liquid-tight manner,
The cap further includes an engagement portion that is engaged with the flange portion from the front end side in a state where the cap is completely screwed to the mouth portion,
When the cap is screwed into the mouth portion, a predetermined clearance is provided between the engaging portion and the flange portion when the convex portion is in an incompletely screwed state in which it just contacts the tip opening. The engaging portion is formed to produce,
The state in which the cap is completely screwed into the mouth portion is a state in which the engaging portion is pressed against the flange portion by additionally tightening the cap from the incompletely screwed state, The liquid container according to claim 1, wherein the liquid container is in a state where an elastic displacement toward the base end side of a displacement amount corresponding to the clearance is generated in the tip opening portion of the nozzle by being pressed toward the base end side by the convex portion.   The cap has a top portion whose inner surface is curved in a dome shape, and the convex portion is provided in the central portion of the top portion, thereby reducing stress concentration around the convex portion due to an external force acting on the convex portion. The liquid container according to claim 1, wherein the liquid container is a liquid container.   The liquid container according to claim 1 or 2, wherein the inner stopper is made of biomass plastic.   The liquid container according to claim 1, wherein the cap is made of biomass plastic.   The liquid container according to claim 1 or 2, wherein the inner plug and the cap are made of biomass plastic.   The liquid container according to claim 5, wherein the inner plug is made of a biomass plastic having a larger elastic coefficient than the cap.   The liquid container according to claim 1, wherein the clearance is 0.1 mm or more and less than 0.3 mm.   A liquid is filled into the container body of the liquid container according to any one of claims 1 to 7, and the cap is screwed into the mouth of the container body with a predetermined tightening torque. A method for storing a liquid container, wherein the method is stored in a completely screwed state.

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