Resealable airtight container

Abstract

To provide a hermetically sealed container that can be resealed by means of a screw engagement and that can also be liquid-tight after resealing.SOLUTION: The hermetically sealed container includes a container and a lid. The container includes a bottom part and a body part. A flange part is formed on the upper end of the body part. The container has at least an outer wall extending downwardly from the outer edge of the flange part. The lid at least includes a surface that covers an opening part of the container and is in close contact with the flange part and a side wall that extends downwards from the surface. The container's outer wall and the lid's side wall include first engagement parts that engage each other using screw engagement. Second engagement parts with which the container and the lid are locked or engaged with each other are formed at a location of a space in the container nearer than the first engagement parts. When the lid is guided to the bottom dead center by the screw engagement of the first engagement parts, the second engagement parts are at least in close contact with each other vertically.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a sealed container having resealability through screw engagement, and more particularly to a sealed container which is lightweight yet can reliably ensure liquid-tightness even after initial opening. [Background technology]

[0002] Containers with lids, which are made by thermoforming a resin sheet and a lid, are widely used as packaging containers for food such as boxed lunches and prepared meals. Even for such containers with lids, there is a demand for resealability, which allows them to be resealed after initial opening when any contents remain. This type of lidded container is generally intended for temporary resealing, and the lid is fixed to the container by engaging or fitting with recessed or protruding portions formed on the container and lid.While this does not cause a problem if the contents are solid, there is a risk of liquid leakage if the contents include liquid, and the container does not have the sealing properties to achieve liquid-tightness. In order to solve such problems, a container with a lid has been proposed in which the container flange and the lid are pressure-welded by screw engagement to improve the sealing performance. For example, the following Patent Document 1 proposes a packaging container comprising a container body having a fitting flange at an opening edge of a perfect circle, the container body being integrally molded from a synthetic resin sheet, and a lid to be fitted thereto by the fitting flange, the container body having a body-side threaded step and a fitting portion formed on an outer skirt portion constituting the fitting flange on the container body side, and a lid body-side threaded step having the same shape as the body-side threaded step and a fitting portion capable of engaging with the fitting portion on the container body side formed on an outer skirt portion constituting the fitting flange on the lid body side, such that when the lid body is fitted to the container body, the two are integrated by the respective engagement of the two steps and the fitting portion, and when the lid body is rotated relative to the container body, the lid body-side threaded step is guided by the body-side threaded step to open the two, the body-side threaded step and the lid body-side threaded step are multiple and equal in number, and a second step portion inclined with respect to the steps is formed on one end side of each of the body-side threaded step and the lid body-side threaded step.

[0003] Furthermore, in the following Patent Document 2, the upper opening of the container body at least comprises a container inner wall portion continuous with the side wall of the container body, a first flange portion extending horizontally from the upper end of the container inner wall portion, and a container side skirt portion extending downward from the outer end of the first flange portion, and the peripheral edge portion of the lid body at least comprises a lid inner wall portion having an area capable of abutting the container inner wall portion over the entire circumference when the lid body is attached to the container body, a second flange portion extending horizontally from the upper end of the lid inner wall portion, and a lid body side skirt portion extending downward from the outer end of the second flange portion, and further, two or more protrusions protruding inward are formed on the lid body side skirt portion, and below the protrusions formed on the lid body side skirt portion A lidded container has been proposed, characterized in that the lid side skirt portion is formed so that when the edge side is abutted against the first flange portion formed at the upper opening of the container body, the lower end of the lid side skirt portion is positioned lower than the lower end of the container side skirt portion, and the container side skirt portion of the container body is formed with a first guide surface that can guide the protrusion formed on the lid side skirt portion downward when the lid is attached, and when the lid is closed, the protrusion is guided downward by the first guide surface, thereby drawing the lid body downward, whereby the seal portion formed between the container inner wall portion and the lid inner wall portion is pressed against each other, ensuring high sealing performance in the seal portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4827479 [Patent Document 2] Patent No. 4872011 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above Patent Document 1, the sealing part of the container is made up of mating flanges, which are pressed together by engaging with screws and fitting together at the fitting parts. Since the fitting position is fixed, this is advantageous in that it prevents the lid from being forgotten to be closed. However, there is a risk that the pressure between the flange faces may be insufficient, and this is still not sufficient in terms of liquid-tightness. In addition, in the above-mentioned Patent Document 2, a protrusion formed on the lid body is guided downward by a guide surface formed on the container side skirt portion, thereby drawing the lid body downward, and thereby pressing the inner wall portion of the lid and the inner wall portion of the container circumferentially to form a seal. However, depending on the degree of rotation of the lid body (the degree to which the lid body is drawn downward), liquid-tightness may not be achieved, and a sealing ability sufficient to reliably achieve liquid-tightness is not obtained.

[0006] SUMMARY OF THE PRESENT DISCLOSURE ... It is therefore an object of the present invention to provide a sealed container which has resealability through thread engagement and which can ensure liquid-tightness even after resealing. [Means for solving the problem]

[0007] According to the present invention, in a sealed container comprising a container comprising a bottom and a body, a flange portion formed at an upper end of the body, and at least an outer wall extending downward from the outer edge of the flange portion, and a lid covering an opening of the container and having at least a surface in close contact with the flange portion and a side wall extending downward from the outer edge of the surface, the outer wall of the container and the side wall of the lid have first engagement portions which engage with each other by screw engagement, and a second engagement portion is formed at a position closer to the container interior space than the first engagement portion, whereby the container and the lid are locked or engaged with each other in the vertical direction, and when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, the second engagement portions come into close contact with each other at least in the vertical direction, the outer wall of the container has a step portion, and an upper outer wall above the step portion is tapered such that the outer diameter of the outer wall decreases as it goes downward, and the side wall of the lid is containera step portion at a position corresponding to the step portion of the lid, a taper is formed in the upper side wall above the step portion of the lid such that the outer diameter of the side wall decreases downward, and a first engagement portion is formed at a position below the step portions of the container and the lid, and when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, the upper outer wall of the container and the upper side wall of the lid are pressed against each other to engage or lock in the vertical direction.

[0008] In the sealed container of the present invention, (1) The lid is a drop-lid-shaped lid having a top surface, an annular side wall extending axially upward from the top surface, an annular surface extending horizontally from an upper end of the annular side wall, and a side wall extending downward from an outer edge of the annular surface, and the second engagement portion is of being formed on an upper portion of an inner wall of a body portion and on the annular side wall; (2) The container of At least a taper is formed in the upper part of the body, the inner diameter of which decreases as it goes upward, and at least a taper is formed in the annular side wall of the lid, the inner diameter of which decreases as it goes upward, and when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, of The upper part of the body and the annular side wall of the lid are pressed against each other to be locked or engaged in the vertical direction. (3) The second engagement portion is of the annular projection formed on the body portion and projecting inwardly from the container and extending in the circumferential direction of the container, and the annular protrusion formed on the annular side wall of the lid and projecting outwardly from the lid and extending in the circumferential direction of the annular side wall, when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, the annular projection and the annular protrusion are pressed against each other to be locked or engaged in the vertical direction; (4) The container of an annular ridge protruding into the container and extending in the circumferential direction of the container is formed on the body, and a taper is formed on the annular side wall of the lid such that the inner diameter decreases toward the top, and when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, the annular ridge and the annular side wall of the lid are pressed against each other to be locked or engaged in the vertical direction; (5) The container of The upper part of the body is at least tapered so that the inner diameter decreases as it goes upward, and the annular side wall of the lid is formed with an annular protrusion that protrudes outward from the lid and extends in the circumferential direction of the annular side wall. When the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, the container of The upper part of the body and the annular protrusion are pressed against each other and are engaged or locked in the vertical direction. and, ( 6 ) The container of The container and the lid are peelably heat-sealed at a flange portion and a surface or annular surface of the lid that is in close contact with the flange portion, or at a step portion of the container and a step portion of the lid; ( 7 ) the screw portion of the first engagement portion is formed at several points among a plurality of arcs obtained by dividing the entire circumference of the body opening of the container, and the container and the lid are peelably heat-sealed when the first engagement portion is not engaged; is preferred. Effect of the Invention

[0009] In the sealed container of the present invention, the lid is fixed to the container in a resealable manner by a first engagement portion that is screw-engaged, and when the lid is fixed to the container by screw engagement, the second engagement portion tightly engages or locks in the vertical direction, thereby reliably blocking the flow path of liquid from the contents and ensuring liquid-tightness. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view showing an example of a container and a lid of a sealed container of the present invention. FIG. [Diagram 2] FIG. 2 is a side cross-sectional view showing a schematic state in which a lid has been applied to the container shown in FIG. 1 and the container has reached bottom dead center. [Diagram 3] 3 is a partially enlarged cross-sectional view showing an enlarged portion X of FIG. 2. [Figure 4] FIG. 4 is a partially enlarged cross-sectional view showing another embodiment of the sealed container of the present invention. [Diagram 5]FIG. 4 is a partially enlarged cross-sectional view showing another embodiment of the sealed container of the present invention. [Figure 6] FIG. 4 is a partially enlarged cross-sectional view showing another embodiment of the sealed container of the present invention. [Figure 7] FIG. 4 is a partially enlarged cross-sectional view showing another embodiment of the sealed container of the present invention. [Figure 8] FIG. 13 is a diagram for explaining a method for measuring opening force. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] As described above, in the sealed container of the present invention, the outer surface of the body of the container and the side wall of the lid have a first engagement portion which engages with each other through screw engagement, and a second engagement portion which engages or locks the container and the lid with each other in the vertical direction is formed at a position closer to the space inside the container than the first engagement portion.An important feature is that when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, the second engagement portion comes into close contact at least in the vertical direction, which enables the resealable screw cap to ensure liquid-tightness. Liquid leakage from sealed containers occurs when liquid travels from the space inside the container up the body of the container toward the top of the container (axial direction) through tiny gaps formed at the press-fit portion (seal portion) of the container and lid. It is important to prevent tiny gaps from forming in the press-fit portion that could serve as a flow path for liquid, but depending on the dimensional accuracy of the container and lid, or the degree of rotation of the lid, there is a risk that the press-fit portion may not be completely sealed. In the present invention, the undercut by the second engagement part that vertically engages or locks the container and the lid together stops the outflow of liquid from the space inside the container toward the top of the container, which is the outflow direction of the liquid, and effectively prevents liquid leakage. In addition, the vertical engagement or lock by the second engagement part is completely in contact when guided to the bottom dead center of the screw engagement, which is the first engagement part, so that the second engagement part does not become incomplete in engagement or lock depending on the turning angle of the screw (degree of tightening of the lid), and it is possible to ensure reliable liquid-tightness by the second engagement part. The sealed container of the present invention will now be described with reference to the accompanying drawings.

[0012] FIG. 1 shows a perspective view of an example of a container and a lid in a sealed container of the present invention, FIG. 2 shows a simplified side cross-sectional view of the sealed container shown in FIG. 1, and FIG. 3 shows an enlarged view of part X in FIG. 2. As shown in Figs. 1 to 3, a sealed container generally designated by 1 comprises a cup-shaped container 10 and a lid 20 in the form of a drop lid. The container 10 is made up of a bottom 11, a body 12, a flange 13 extending radially outward from the upper end of the body 12, and an outer wall 14 hanging down from the outer periphery of the flange 13. In the specific example shown in the figure, a container tapered section 16, whose inner diameter decreases upward, is formed above the body 12 via a step 17. The outer wall 14 is made up of an upper outer wall 14a and a lower outer wall 14b via a step 18, and the upper outer wall 14a is formed in a tapered shape such that the outer diameter of the outer wall decreases downward, and a thread section 15 is formed on the outer surface of the lower outer wall 14b. On the other hand, the lid 20 is composed of a top surface 21 covering the container opening, an annular side wall 22 extending upward from the outer periphery of the top surface 21, an annular surface 23 extending radially outward from the upper end of the annular side wall 22, and an outer wall 24 hanging down from the outer periphery of the annular surface 23. In the specific example shown in the figure, the annular side wall 22 is inclined to have the same inclination angle as the container tapered portion 16. The outer wall 24 is composed of an upper outer wall 24a and a lower outer wall 24b with a step 26 between them, the upper outer wall 24a is inclined to have the same inclination angle as the upper outer wall 14a of the container described above, and a threaded portion 25 is formed on the inner surface of the lower outer wall 24b. Although not essential, it may also have a flange portion 29 as shown in FIG. 1. 1, a short spiral-shaped screw portion 25 is formed on the lid 20, and guide surfaces A and B are formed on the container 10 as the screw portion 15. When closing the lid, with the lid 20 placed on the container 10, the screw portion 25 is guided downward by guide surface A when the lid 20 is turned clockwise relative to the container 10, and the lid 20 reaches the bottom dead center. When opening the lid, with the lid 20 at the bottom dead center, the screw portion 25 is guided upward by guide surface B when the lid 20 is turned counterclockwise relative to the container 10. 1, the screw portion 25 has a short spiral shape, but the protrusion shape may be a circle, an ellipse, or another polygon, and may be a protrusion shape extending in the circumferential direction. Also, the guide surface A and the guide surface B may be formed on the lid 20, and the screw portion having a short spiral shape or the like may be formed on the container 10.

[0013] In the sealed container shown in Figures 1 to 3, when the lid 20 reaches bottom dead center due to the screw engagement which is the first engagement part, liquid-tightness is achieved by the close contact between the tapered surface of the container tapered portion 16 which is the second engagement part and the annular side wall 22 of the lid, and by the close contact between the upper outer wall 14a of the container and the upper outer wall 24a of the lid, and liquid-tightness is also improved by the pressure bonding between the container flange portion 13 and the annular surface 23 of the lid. That is, the container tapered portion 16 formed above the container body 12 is pressed against the tapered surface of the annular side wall 22 of the lid, the inner diameter of the body decreasing toward the top, and the tapered surface becomes an obstacle to liquid flowing upward, so that a higher level of liquid tightness can be achieved compared to a case where the contact surface extends vertically in the axial direction. Similarly, the upper outer wall 14a of the container and the upper outer wall 24a of the lid are pressed against each other with a tapered surface whose outer and inner diameters decrease toward the bottom, so that the tapered surface becomes an obstacle to liquid flowing downward, so that a higher level of liquid tightness can be achieved compared to a case where the contact surface extends vertically in the axial direction. Furthermore, the container flange portion 13 and the annular surface 23 of the lid are pressed against each other by the screw engagement, so that the liquid tightness can be further improved. The step 26 on the lid side that comes into close contact with the step 18 of the container may be heat sealed in a peelable manner, ensuring liquid tightness until initial opening. Also, by making the heat seal easily peelable, the heat sealed portion can be peeled off by turning the screw engagement. Furthermore, by not heat sealing the entire circumference of the opening of the container, but heat sealing only a portion of the surface of the step 26 on the lid side that comes into close contact with the step 18 of the container, the ease of peeling during initial opening can be improved.

[0014] FIG. 4 is a view showing another embodiment of the sealed container of the present invention, and is an enlarged view of the portion corresponding to the portion X in FIG. The container 10 shown in Fig. 4 has, above the container body 12, a container tapered section 16 in which the inside diameter of the container decreases toward the top, a flange section 13 extending radially outward from the upper end of the container tapered section 16, and a screw section 15 formed on the outer surface of the outer wall 14, which is the same as the sealed container shown in Fig. 2, and the container tapered section 16 is formed in the body 12 via a step 17, which is the same as the sealed container shown in Fig. 3. In the container shown in Fig. 4, a container-side heat seal section 19 extending radially outward from the lower end of the outer wall 14 is formed. On the other hand, the lid 20 is the same as the sealed container shown in Fig. 1 in that it has a top surface 21 covering the container opening, an annular side wall 22 extending upward from the outer periphery of the top surface 21, an annular surface 23 extending radially outward from the upper end of the annular side wall 22, and an outer wall 24 having a screw portion 25 on its inner surface. In the lid 20 shown in Fig. 4, a lid-side heat-sealed portion 27 is formed which extends radially outward from the lower end of the outer wall 24 and is in close contact with the container-side heat-sealed portion 19.

[0015] In the sealed container shown in Fig. 4, in addition to the liquid-tightness provided by the close contact of the tapered surface between the container tapered portion 16 and the annular side wall 22 of the lid, and the close contact between the container flange portion 13 and the annular surface 23 of the lid, as in the case of Fig. 3, the container-side heat-sealed portion 19 and the lid-side heat-sealed portion 27 are peelably heat-sealed, thereby reliably ensuring liquid-tightness until the initial opening. Furthermore, at the time of resealing after peeling off the heat-sealed portion due to the initial opening, liquid-tightness can be ensured by the pressure contact between the container flange portion 13 and the annular surface 23 of the lid due to the screw engagement, and by the close contact due to the tapered shape fitting of the container tapered portion 16 and the annular side wall 22 of the lid, which reduces the container inner diameter toward the top of the container, as in the case of the sealed container shown in Fig. 3. In an embodiment in which peeling of the heat-sealed portion is required for initial opening, such as the embodiment shown in FIG. 4, peeling of the heat-sealed portion may cause distortion of the lid depending on the heat-seal strength. However, by using a heat-seal that is weak and easily peelable, the heat-sealed portion can be peeled off by turning the screw engagement. Although peeling is possible, the heat-sealed portion cannot be peeled off by moving the screw portion to the top dead center. If the heat seal strength is high, it is possible to improve ease of peeling when initially opened by not heat sealing the entire circumference of the container opening, but only heat sealing a portion of the surface.

[0016] In the sealed container shown in Figure 5, an annular ridge 30 is formed on the upper inner surface of the container body 12, and an annular protrusion 28 is formed on the outer surface of the annular side wall 22 of the lid. When the lid is guided to the bottom dead center of the screw engagement, the lower surface of the annular ridge 30 and the upper surface of the annular protrusion 28 tightly engage with each other, thereby effectively preventing liquid from leaking out of the contents and achieving liquid-tightness.

[0017] (Other Aspects) The sealed container of the present invention is not limited to the specific examples shown in Figures 1 to 5 and can be modified in various ways, as long as a second engagement portion is formed that is in close contact at least in the vertical direction when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion. For example, in the specific example shown in Figures 3 and 4 described above, an easily peelable heat seal can be formed between the container flange portion 13 and the annular surface 23 of the lid, or an easily peelable heat seal can be formed between the step 18 of the container and the step 26 of the lid.In another embodiment, as shown in Figure 6, the upper outer wall 14a and the upper outer side wall 24a of Figure 3 are tapered and heat sealed to each other in a peelable manner, thereby ensuring reliable liquid-tightness until initial opening. In addition, as in the specific example shown in Fig. 2, when the liquid-tightness is realized by pressing the tapered surface, the maximum outer diameter φ1 of the annular side wall 22 of the lid can be set to be larger than the maximum inner diameter φ2 of the container tapered part 16 (φ1>φ2) and / or the minimum inner diameter φ3 of the upper outer wall 24 (or 24a) of the lid can be set to be smaller than the minimum outer diameter φ4 of the upper outer wall 14 (or 14a) of the container (φ3<φ4). This allows the tapered part and the annular side wall, or the upper outer wall and the upper outer wall, to be pressed not only in the vertical direction but also in the radial direction, thereby further improving the liquid-tightness. Note that the liquid-tightness is improved by setting both the relationship between the diameter of the annular side wall and the tapered part and the relationship between the diameter of the upper outer wall and the upper outer wall as described above, but only one of them may be set to the above relationship from the viewpoint of plugging property, etc.

[0018] In the specific example shown in Fig. 5, the annular ridge and the annular projection are formed on the vertical container body and annular side wall, but they may of course be formed on tapered surfaces as shown in Figs. 2 to 4. This can further improve the liquid-tightness. 5, both of the second engaging portions are formed as protrusions, such as the annular ridge of the container body and the annular protrusion of the annular side wall, but one of them may be a recess.Other combinations of the second engaging portions include engagement between the annular ridge of the container body and the tapered surface of the annular side wall, and engagement between a tapered portion formed on the upper part of the container body and the annular protrusion of the annular side wall. Furthermore, in the specific examples shown in Figures 2 to 6, the lid was a drop-lid shape with an annular side wall, but as shown in Figure 7, by forming a second engagement portion by tapering the upper outer wall 14a of the container, a cover lid shape without an annular side wall portion may be used.

[0019] The inclination angle of the container tapered portion 16 and the container upper outer wall 14 (or 14a) relative to the axial direction cannot be generally determined depending on the container's opening diameter, the axial length of the tapered portion, or the presence or absence of other tapered portions, but is preferably in the range of 0.1° to 45°, more preferably 1 to 30°, and even more preferably 1 to 20°. In addition, it is desirable that the inclination angle Θ1 of the container tapered portion or the upper outer wall 14 (or 14a) of the container relative to the axial direction is the same as the inclination angle Θ2 of the annular side wall 22 or the upper outer wall 24 (or 24a) relative to the axial direction in terms of adhesion between the two, but for example, by making the inclination angle Θ2 of the annular side wall 22 (upper outer wall 24) slightly different from the inclination angle Θ1 of the container tapered portion 16 (upper outer wall 14), the annular side wall 22 (upper outer wall 24) presses the container tapered portion 16 (upper outer wall 14) radially outward, improving the adhesion between the two. On the other hand, if the difference (Θ1-Θ2) is too large, it becomes difficult to open and close the lid, so it is preferable that the difference be 10° or less.

[0020] The first engagement portion, the screw engagement, may be formed over the entire circumference of the container, but when forming a heat-sealed portion or the like, it is preferable to form the screw only in a part of the circumference and heat seal the screw in a state (position) where it is not engaged. In this case, the screw is peeled off in a state where it is not engaged, which makes the initial opening operation easier. That is, in the specific example of FIG. 1, the screw portion 25 is formed so that the lid 20 does not interfere with the guide surface A and the guide surface B when it reaches the bottom dead center. In addition, in the embodiment shown in FIG. 1, the screw engagement which is the first engagement part is configured so that the lid reaches the bottom dead center by rotating clockwise, but of course the screw engagement may be configured so that the lid is closed by rotating counterclockwise, and this can be changed as appropriate depending on the application. Furthermore, the screw engagement of the first engagement portion may be a single-thread screw as shown in Figures 1 to 3, or the screw engagement used in conventional screw lids can be appropriately set depending on the height of the outer wall of the container and the outer wall of the lid, etc.

[0021] (Containers and lids) In the sealed container of the present invention, the container is preferably cup-shaped, but is not limited thereto, and may be tray-shaped or bottle-shaped as long as it has a circular opening that can be screw-engaged. Also, as described above, the lid may be a drop lid or a cover lid. The material of the container may be metal or glass when no heat seal portion is formed, but is preferably resin from the viewpoints of flexibility, heat sealability, and moldability. The material of the lid is preferably resin from the viewpoints of flexibility and heat sealability.

[0022] The container and the lid can be made of a conventionally known thermoplastic resin, such as an olefin resin, a polyester resin, or the like, which has been conventionally used for molding resin containers. As described above, in the airtight container of the present invention, from the viewpoint of ensuring reliable liquid-tightness until initial opening, it is preferable that the container has a peelable heat-sealed joint in addition to the first and second engagement parts. Since such heat seals are required to be able to reliably maintain the airtight state and be easily peelable in the initial opening operation, it is preferable to adjust the adhesive strength by the combination of resins constituting the container and the lid. As an adhesive strength suitable for satisfying both the sealing performance and the easy-opening performance, the opening force (peel strength) measured by attaching a push-pull gauge to the gripping part of the lid and pulling it up in a 45-degree direction relative to the lid as shown in FIG. 8 is preferably in the range of 0.3 to 3.0 kgf, more preferably in the range of 0.5 to 2.5 kgf. The peeling properties are not particularly limited, and resin materials of cohesive peeling, interfacial peeling, or interlayer peeling type may be used. As a combination of such resins, an appropriate combination of two or more thermoplastic resins that have heat sealability and are incompatible may be used.

[0023] For example, when the container is made of a propylene-based polymer, the lid can be made of a blend of an ethylene-based polymer and a propylene-based polymer, thereby ensuring airtightness while maintaining easy opening, and the peel strength can be adjusted by appropriately changing the blend ratio of the blend. Examples of the propylene-based polymer include homopolypropylene, as well as block copolymers and random copolymers of propylene and ethylene or other α-olefins, such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, etc. Examples of the ethylene-based polymer include ethylene homopolymers such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-high density polyethylene (MDPE, HDPE), etc., copolymers of ethylene and other α-olefins, such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, etc., and vinyl monomers, such as (meth)acrylic acid, ethyl (meth)acrylate, methyl (meth)acrylate, vinyl acetate, styrene, etc., and ionomers. In addition to the above-mentioned combinations of olefin-based polymers, the blends may also include combinations of the above-mentioned olefin-based polymers with thermoplastic polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and isophthalate-modified copolymers thereof, polycarbonate resins, polyacrylonitrile resins, etc. When a propylene-based polymer and an ethylene-based polymer are used as a blend, in order to ensure that a flange member made of the blend exhibits good peelability from a container body made of a propylene-based polymer, it is preferable to suitably use a blend in which a propylene-based polymer and an ethylene-based polymer are blended in a weight ratio in the range of 5:5 to 9.5:0.5. The container may be a single layer of the above-mentioned resin, but may also be a multi-layer structure having a gas barrier intermediate layer, so long as the portion that will become the heat seal portion satisfies the above-mentioned conditions.

[0024] (Manufacturing method) In the sealed container of the present invention, the container and the lid can be manufactured by various methods such as injection molding, compression molding, thermoforming, etc., so long as they have the above-mentioned configuration, but it is particularly preferable to integrally mold the resin sheet by thermoforming such as vacuum pressure molding, plug-assisted pressure molding, etc., because this makes molding easy. In addition, by thermoforming the resin sheet, a multilayer container or a multilayer lid can be easily molded using the multilayer sheet. For example, but not limited to, there can be mentioned a flexible laminate comprising inner and outer layers made of the above-mentioned thermoplastic resins, a gas barrier intermediate layer, etc. Examples of materials constituting the gas barrier intermediate layer include metal foils such as aluminum foil, inorganic vapor deposition films, gas barrier resins such as ethylene-vinyl alcohol copolymers, etc. [Industrial Applicability]

[0025] The sealed container of the present invention maintains liquid-tightness even after resealing, and can therefore be used as a container for storing not only viscous substances but also foods and beverages that contain a lot of moisture. [Explanation of symbols]

[0026] 1 sealed container, 10 container, 11 bottom, 12 body, 13 flange portion, 14 outer wall, 15 screw portion, 16 container tapered portion, 17 step, 18 step, 19 heat seal portion, 20 lid, 21 top surface, 22 annular side wall, 23 annular surface, 24 outer wall, 25 screw portion, 26 step, 27 heat seal portion, 28 annular protrusion, 30 annular ridge.

Claims

1. A container comprising a bottom and a body, a flange formed at an upper end of the body, and at least an outer wall extending downward from an outer edge of the flange, and a lid covering an opening of the container and having at least a surface in close contact with the flange and a side wall extending downward from the outer edge of the surface, an outer wall of the container and a side wall of the lid have a first engagement portion that engages with each other by screw engagement, and a second engagement portion that vertically locks or engages the container and the lid with each other is formed at a position closer to the container interior space than the first engagement portion; When the cover is guided to the bottom dead center by the screw engagement of the first engagement portion, the second engagement portions are in close contact with each other at least in the up-down direction, an outer wall of the container having a step portion, an upper outer wall above the step portion having a taper such that the outer diameter of the outer wall decreases as it goes downward, a side wall of the lid having a step portion at a position corresponding to the step portion of the container, an upper side wall above the step portion of the lid having a taper such that the outer diameter of the side wall decreases as it goes downward, and a first engagement portion is formed at a position below the step portions of the container and the lid, and when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, the upper outer wall of the container and the upper side wall of the lid are pressed against each other to engage or engage in the vertical direction.

2. 2. The sealed container of claim 1, wherein the lid is a drop-lid-shaped lid having a top surface and an annular side wall extending axially upward from the top surface, an annular surface extending horizontally from the upper end of the annular side wall, and a side wall extending downward from the outer edge of the annular surface, and the second engagement portion is formed on an upper portion of the inner wall of the body of the container and on the annular side wall.

3. 3. The sealed container according to claim 2, wherein the upper part of the body of the container is at least tapered such that the inner diameter decreases as it goes upward, and the annular side wall of the lid is at least tapered such that the inner diameter decreases as it goes upward, and when the lid is guided to the bottom dead center by the screw engagement of the first engaging portion, the upper part of the body of the container and the annular side wall of the lid are pressed against each other to engage or lock in the vertical direction.

4. 3. The sealed container according to claim 2, wherein the second engagement portion comprises an annular ridge formed on the body of the container, protruding inwardly from the container and extending circumferentially around the container, and an annular protrusion formed on the annular side wall of the lid, protruding outwardly from the lid and extending circumferentially around the annular side wall, and when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, the annular ridge and the annular protrusion are pressed against each other to engage or lock in the vertical direction.

5. 3. The sealed container according to claim 2, wherein a body portion of the container is formed with an annular ridge protruding inwardly from the container and extending circumferentially around the container, and the annular side wall of the lid is at least tapered so that its inner diameter decreases upward, and when the lid is guided to the bottom dead center by the screw engagement of the first engagement portion, the annular ridge and the annular side wall of the lid are pressed against each other to engage or lock in the vertical direction.

6. 3. The sealed container according to claim 2, wherein the upper part of the body of the container is at least tapered such that the inner diameter decreases going upward, and the annular side wall of the lid is formed with an annular protrusion that protrudes outward from the lid and extends in the circumferential direction of the annular side wall, and when the lid is guided to the bottom dead center by the screw engagement of the first engaging portion, the upper part of the body of the container and the annular protrusion are pressed against each other to engage or lock in the vertical direction.

7. 7. A sealed container according to any one of claims 1 to 6, wherein the container and the lid are peelably heat-sealed at a surface or annular surface that is in close contact with the flange portion of the container and the flange portion of the lid, or at a step portion of the container and a step portion of the lid.

8. 8. The sealed container according to claim 7, wherein the screw portion in the first engagement portion is formed at several points among a plurality of arcs obtained by dividing the entire circumference of the body opening of the container, and the container and the lid are peelably heat-sealed when the first engagement portion is not engaged.

Images