Plastic lid

Abstract

To provide a container lid which improves sealability with a simple constitution and can suppress liquid leakage.SOLUTION: A resin lid 1 is provided in a container 100. The container 1 has a container fitting part 103 provided in a container opening 104. The resin lid 1 has a lid top surface 10, and a lid fitting part 30 which is provided in the periphery of the lid top surface 10 and is fit into the paper container fitting part 103. The lid fitting part 30 has a lid fitting part outer wall 31, a lid fitting part top part 32, and a lid fitting part inner wall 33. The lid fitting part inner wall 33 faces a body part 102 of the paper container. An under projection 36 projecting in a circumferential outer direction is provided below the lid fitting part inner wall 33. A step rib part 12 is provided on the lid top surface 10 so as to be adjacent to the lid fitting part inner wall 33. The step rib part 12 is composed of a width part 13 extending in a horizontal direction, and a height part 14 extending in an upper direction from the end of the width part. The height part 14 of the step rib part corresponds to the position of the under projection 36.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a resin lid provided on a container.

Background Art

[0002] For containers for beverages and foods with a lot of juice, it is preferable to have a lid. By devising the fitting structure between the lid and the container, for example, liquid leakage during transportation can be suppressed.

[0003] Common containers include paper containers, resin containers, aluminum containers, etc. in terms of material, and circular containers (including inverted frustum of a cone), rectangular containers (including inverted trapezoid) in terms of shape. In any case, as a basic configuration, they include a bottom, a body portion erected from the bottom, and a flange portion formed at the upper end of the body portion. An opening is formed at the upper end of the body portion.

[0004] The lid is fitted to the flange portion. A fitting space surrounding the container flange is formed at the peripheral edge of the lid. At this time, when the upper part of the inner wall of the container body portion and the lid fitting portion are in surface contact, the sealing performance is improved. In particular, the longer the contact length (contact area) in the vertical direction, the better the sealing performance (for example, Patent Document 1 or Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, the lids and lid fitting structures described in Patent Document 1 or Patent Document 2 have sufficient sealing performance. However, these days, as the demand for delivering beverages and foods by motorcycle or bicycle increases, liquid leakage troubles due to container overturning and the like are also increasing. Therefore, it is necessary to further improve the sealing performance.

[0007] Although the manufacturing precision of the container and the lid described in Patent Document 1 or Patent Document 2 are sufficient, even slight dimensional errors can reduce the airtight seal.

[0008] The present invention aims to solve the above problems and to provide a container lid that can improve airtightness and suppress liquid leakage with a simple structure. [Means for solving the problem]

[0009] The resin lid of the present invention, for achieving the above objective, comprises a lid top surface and a lid fitting portion provided around the lid top surface and fitting with a container fitting portion provided at the container opening. The lid fitting portion has an outer wall of the lid fitting portion, a top portion of the lid fitting portion, and an inner wall of the lid fitting portion. The inner wall of the lid fitting portion faces the body of the container. The inner wall of the lid fitting portion is provided with an under projection that protrudes outward in the circumferential direction. The lid top surface is provided with a stepped rib portion adjacent to the inner wall of the lid fitting portion, and the stepped rib portion consists of a width portion extending horizontally and a height portion extending upward from the end of the width portion, and the height of the stepped rib portion corresponds to the position of the under projection.

[0010] The under projection deforms and adheres tightly to the container body. At this time, the stepped rib section functions as a rib, resisting the elastic deformation of the under projection. This ensures that the under projection functions reliably.

[0011] In the above invention, preferably, the width of the stepped rib is 1 to 3 times the height of the stepped rib. Approximately 2 times is preferable.

[0012] This allows the stepped rib to function as a rib.

[0013] In the above invention, preferably, the thickness of the under projection is thinner than the thickness of the stepped rib.

[0014] Under-protrusions have low rigidity and are easily deformed. Stepped ribs have high rigidity and are less prone to deformation.

[0015] The resin lid of the present invention for achieving the above object includes a lid top surface, and a lid fitting portion provided around the lid top surface and fitting with a container fitting portion provided at an opening of a container. The lid fitting portion has an outer wall of the lid fitting portion, a top portion of the lid fitting portion, and an inner wall of the lid fitting portion. The inner wall of the lid fitting portion faces the body portion of the container. An under protrusion protruding in the circumferential outer direction is provided on the inner wall of the lid fitting portion. A first step rib portion is provided on the lid top surface so as to be adjacent to the inner wall of the lid fitting portion, and a second step rib portion is provided so as to be adjacent to the first step rib portion.

[0016] The first step rib portion functions as a rib and counteracts the elastic deformation of the under protrusion. The second step rib portion assists the rib function of the first step rib portion.

[0017] In the above invention, preferably, the taper angle of the inner wall of the lid fitting portion is equal to the taper angle of the paper container, a step protrusion protruding in the circumferential outer direction is provided on the inner wall of the lid fitting portion above the under protrusion, and the height of the second step rib portion corresponds to the position of the step protrusion.

[0018] The step protrusion presses the body portion of the container and improves the sealing property. At this time, the second step rib portion functions as a rib and counteracts the pressing force of the step protrusion.

Advantages of the Invention

[0019] The lid of the present invention can improve the sealing property and suppress liquid leakage.

Brief Description of the Drawings

[0020] [Figure 1] Schematic Configuration Diagram of a Container with a Lid [Figure 2] Schematic Configuration Diagram of a Lid [Figure 3] Detailed Configuration Diagram of a Lid <着 [Figure 4] Schematic Explanation Diagram of the Fitting Operation between a Lid and a Container [Figure 5] Detailed Explanation Diagram of the Contact State between the Inner Wall of the Lid Fitting Portion and the Body Portion of the Container [Figure 6] Operation Explanation Diagram of the Second Step Rib [Figure 7] Modification Example [Figure 8] Application Examples to Containers Other Than Circular Paper Containers

Modes for Carrying Out the Invention

[0021] ~Basic Structure~ FIG. 1 is a schematic configuration diagram of a container with a lid. First, the basic structure will be described. The container with a lid consists of a lid 1 and a container 100.

[0022] The container 100 is made of, for example, paper. Generally, it is laminated. It includes a bottom portion 101, a body portion 102, and a flange portion 103. The bottom portion 101 is circular in plan view. The body portion 102 is substantially frustum-shaped in side view and stands upright from the bottom portion 101. The flange portion 103 formed at the upper end of the body portion 102 is formed at the upper end of the body portion 102 and is formed in a curled shape on the outer periphery.

[0023] An opening 104 is formed at the upper end of the body portion 102. The lid 1 is fitted to the flange portion 103 to close the opening 104.

[0024] The lid 1 is made of resin. For example, it is made of polypropylene. It may also be made of polyethylene, polyethylene terephthalate, polystyrene, etc.

[0025] ~Lid Structure~ FIG. 2 is a schematic configuration diagram of the lid. FIG. 3 is a detailed configuration diagram of the lid.

[0026] The lid 1 consists of a lid top surface 10 and a lid fitting portion 30. The lid fitting portion 30 is provided at the periphery of the lid top surface 10 and fits with a container fitting portion (flange portion 103) provided at the container opening 104.

[0027] The lid fitting portion 30 has a lid fitting portion outer wall 31, a lid fitting portion top 32, and a lid fitting portion inner wall 33. That is, the lid fitting portion outer wall 31 and the lid fitting portion inner wall 33 face each other, and the lid fitting portion outer wall 31 and the lid fitting portion inner wall 33 are continuous with the lid fitting portion top 32 at the upper end, forming a substantially U-shaped (gate-shaped) structure and forming a fitting space 34 surrounded by the U-shaped structure.

[0028] An under projection 36 is provided on the lower part of the inner wall 33 of the lid fitting portion, and a stepped projection 37 is provided in the middle of the inner wall 33 of the lid fitting portion, above the under projection 36 (details will be described later).

[0029] The structure of the lid top surface 10 will now be described. The central part 11 of the lid top surface is located in the center of the lid top surface 10.

[0030] The stepped rib portion 12 is provided on the top surface 10 of the lid so as to be adjacent to the inner wall 33 of the lid fitting portion. The stepped rib portion 12 consists of a width portion 13 and a height portion 14. The width portion 13 extends horizontally from the lower end of the inner wall 33 of the lid fitting portion. The height portion 14 extends diagonally upward from the end of the width portion 13. The taper is preferably about 0 to 45 degrees.

[0031] The stepped rib portion 15 is provided on the top surface 10 of the lid adjacent to the stepped rib portion 12. The stepped rib portion 15 consists of a width portion 16 and a height portion 17. The width portion 16 extends horizontally from the upper end of the height portion 14 of the stepped rib portion 12. The height portion 17 extends diagonally upward from the end of the width portion 16. A taper of approximately 0 to 45 degrees is preferable.

[0032] The stepped rib portion 18 is provided on the top surface 10 of the lid adjacent to the stepped rib portion 15. The stepped rib portion 18 consists of a width portion (numbering omitted) and a height portion (numbering omitted). The width portion of the stepped rib portion 18 extends horizontally from the upper end of the height portion 17 of the stepped rib portion 15. The height portion of the stepped rib portion 18 extends downward from the end of the width portion of the stepped rib portion 18 and is continuous with the periphery of the central portion 11 of the top surface of the lid.

[0033] Furthermore, the central part 11 of the top surface of the lid is provided with multiple (five in the figure) stepped rib portions 19 that are roughly uniform in the circumferential direction and protrude radially.

[0034] ~Protrusion~ An under projection 36 is provided on the lower part of the inner wall 33 of the lid fitting portion, and a stepped projection 37 is provided in the middle of the inner wall 33 of the lid fitting portion, above the under projection 36. In the illustrated preferred example, one under projection 36 and three stepped projections 37 are provided, but the number is not limited.

[0035] The under projection 36 is provided to protrude outward along the circumference. In the illustrated preferred example, it has a semi-elliptical shape in vertical cross-section. For example, when the height of the inner wall 33 of the lid fitting portion is about 10 mm, the major axis diameter of the under projection 36 is preferably about 1 to 3 mm, and the minor axis diameter is preferably about 0.5 to 1.2 mm. In addition to a semi-elliptical shape, a curved shape in vertical cross-section, such as a semicircle or semi-ellipse, is also preferable because it does not hinder the deformation of the under projection when the lid is fitted.

[0036] The stepped projection 37 is provided to protrude outward along the circumference. In the illustrated preferred example, it is a right triangle in vertical cross-section. The stepped projection 37 is formed by extending vertically downward from the upper end and horizontally from the lower end. For example, if the height of the inner wall 33 of the lid fitting portion is about 10 mm, the height of the stepped projection 37 is preferably about 1 to 2 mm and the width is preferably about 0.1 to 0.3 mm.

[0037] The stepped projection 37 can be any shape, not necessarily triangular, as long as it ensures adequate rigidity when the lid is fitted. A square shape or other shapes are also acceptable.

[0038] The dimensions mentioned above are examples to facilitate understanding of the invention and are not limited to these dimensions.

[0039] ~Thick and meaty~ This paper examines the wall thickness of the resin lid. The dimensions below are examples to facilitate understanding of the invention and are not limited to these dimensions. For example, a film with a thickness of 0.3 mm is molded.

[0040] The thickness of the outer wall 31 of the lid fitting portion is 0.17 to 0.21 mm, the thickness of the top portion 32 of the lid fitting portion is 0.25 to 0.27 mm, the thickness of the upper part of the inner wall 33 of the lid fitting portion where no protrusion is formed is 0.21 to 0.24 mm, the thickness of the stepped protrusion 37 is 0.15 to 0.20 mm, and the thickness of the under protrusion 36 is 0.12 to 0.14 mm.

[0041] The thickness of the stepped rib section 12 and the height section 14 is 0.12 to 0.16 mm, and the thickness of the stepped rib section 15 and the height section 17 is 0.18 to 0.21 mm.

[0042] In other words, the under projection 36 is the thinnest and is easily deformed due to its low rigidity.

[0043] Furthermore, the formation of a stepped projection 37 in the middle of the inner wall 33 of the lid fitting portion causes the sheet to extend to the stepped portion, and the vertical distance is further increased, thus ensuring that the under projection 36 can be made thinner.

[0044] ~Mating~ Figure 4 is a schematic diagram showing the fitting operation of the lid 1 and the container 100. The container flange portion 103 is fitted into the fitting space 34 of the lid fitting portion 30. The outer wall 31 of the lid fitting portion is recessed inward to correspond to the shape of the container flange portion 103.

[0045] When fitted, the inner wall 33 of the lid fitting portion and the container body 102 face each other. In particular, it is preferable that the taper angle of the inner wall 33 of the lid fitting portion is equal to the taper angle of the paper container 102, and that the inner wall 33 of the lid fitting portion and the container body 102 are in contact as much as possible. This improves airtightness.

[0046] Figure 5 is a detailed view of the contact state between the inner wall 33 of the lid fitting portion and the container body 102 when fitted. The under projection 36 is provided to protrude outward along the circumference.

[0047] A reaction force acts on the container body 102. The under projection 36 is easily displaced due to the combined effect of its curved shape and thin wall. The elastic force of the under projection 36 further improves the airtightness with the inner wall of the container body 102. As a result, liquid leakage can be suppressed with a simple configuration.

[0048] While the under projection 36 is easily deformed, the stepped projection 37 has high rigidity (is less prone to displacement) due to the synergistic effect of its right-angled triangular shape and relatively thick wall. The stepped projection 37 is provided to protrude outward along the circumference. The convex portion of the stepped projection 37 presses against the container body 102. The pressing force of the stepped projection 37 improves the airtightness.

[0049] On the other hand, the stepped rib section 12 functions as a rib (details will be described later). Furthermore, the thickness of the stepped rib section 12 is about the same as or slightly thicker than the thickness of the under projection 36. The stepped rib section 12 has high rigidity (it is less prone to displacement) due to the synergistic effect of its rib function and thickness.

[0050] When the under projection 36 deforms and attempts to return to its original shape, the under projection 36 is held between the container body 102 and the stepped rib portion 12, and the elastic force of the under projection 36 is maintained.

[0051] This creates a rigid 12-flexible 36-rigid 37 structure. Because the flexible structure is sandwiched between the rigid structures, the under projection 36 cannot escape upward or radially towards the center, and the under projection 36 reliably deforms in the circumferential direction along the inner wall of the container body 102, thereby suppressing liquid leakage.

[0052] The stepped rib section 15 functions as a rib (details will be described later). The stepped rib section 15 resists the pressing force of the stepped projection 37 and also assists the rib function of the stepped rib section 12.

[0053] ~Stepped Ribs~ The stepped rib portion 12 is provided on the top surface 10 of the lid so as to be adjacent to the inner wall 33 of the lid fitting portion. The stepped rib portion 12 consists of a width portion 13 and a height portion 14.

[0054] The height portion 14 of the stepped rib portion 12 corresponds to the position of the under projection 36. In the illustrated example, the upper and lower ends of the under projection 36 are included between the upper and lower ends of the height portion 14. For example, if the height of the inner wall 33 of the lid fitting portion is about 10 mm and the major axis diameter of the under projection 36 is about 1 to 3 mm, it is preferable that the height of the height portion 14 be about 1 to 4 mm. Alternatively, it is preferable that the height of the height portion 14 be about 1.0 to 1.5 times the major axis diameter of the under projection 36. More specifically, the stepped rib portion 12 is continuous between the outer end of the width portion 13 and the lower end of the under projection 36 via another small arc. Note that the under projection 36 is more easily deformed via the small arc.

[0055] It is preferable that the width portion 13 is within a predetermined width so that the stepped rib 12 functions as a rib. If the width portion 13 is too long, it will bend and sufficient rib rigidity cannot be obtained. If the height portion 14 is about 1 to 4 mm, it is preferable that the width of the width portion 13 be 2 to 6 mm. Alternatively, it is preferable that the width of the width portion 13 be about twice the height of the height portion 14. The above dimensions are examples to facilitate understanding of the invention and are not limited to each dimension.

[0056] As a result, the stepped rib section 12 functions as a rib and resists the elastic force of the under projection 36.

[0057] Figure 6 is an explanatory diagram of the operation of the stepped rib section 15.

[0058] The stepped rib portion 15 is provided on the top surface 10 of the lid so as to be adjacent to the stepped rib portion 12. The stepped rib portion 15 consists of a width portion 16 and a height portion 17.

[0059] The height portion 17 of the stepped rib portion 15 corresponds to the position of the stepped projection 37. In the illustrated example, the lower end position of the height portion 17 of the stepped rib portion 15 roughly corresponds to the lower end positions of the three stepped projections 37. The upper end position of the height portion 17 of the stepped rib portion 15 is located at a position approximately 1.5 times the total height of the three stepped projections 37. For example, if the height of the inner wall 33 of the lid fitting portion is approximately 10 mm and the total height of the three stepped projections 37 is approximately 3 to 6 mm, then it is preferable that the height of the height portion 17 be approximately 2 to 8 mm. Alternatively, it is preferable that the height of the height portion 17 be approximately 0.5 to 1.5 times the total height of the three stepped projections 37.

[0060] It is preferable that the width portion 16 is within a predetermined width so that the stepped rib 15 functions as a rib. If the width portion 16 is too long, it will bend and sufficient rib rigidity cannot be obtained. If the height of the height portion 17 is about the same as the height of the three stepped protrusions 37, it is preferable that the width of the width portion 16 is about the same as the height portion 17. For example, it is preferable that the width of the width portion 16 is about 0.5 to 1.5 times the height of the height portion 17. The above dimensions are examples to facilitate understanding of the invention and are not limited to each dimension.

[0061] As a result, the stepped rib portion 15 resists the pressing force of the stepped projection 37 and also assists the rib function of the stepped rib portion 12.

[0062] ~Verification during falls~ The airtightness of the lid of this invention was verified as follows. However, since the paper container is formed by overlapping the roughly fan-shaped blank ends, a step is created at the overlapping point. When the container is tipped over, there is a risk of liquid leakage due to this step or slight dimensional error.

[0063] (Verification Example 1) Room temperature coffee was placed inside, and the time it took for dripping to begin after tipping was measured. Comparing five conventional examples without the under-protrusion 36-stepped rib section 12 structure with five examples with the under-protrusion 36-stepped rib section 12 structure, the conventional examples started dripping in an average of 4 seconds, while the examples started dripping in an average of 13 seconds. Although it is not possible to completely prevent liquid leakage, the time for starting dripping was extended by nearly three times, indicating that liquid leakage is suppressed.

[0064] According to the above verification, if the container is righted within a few seconds of tipping over, liquid leakage can be prevented.

[0065] (Verification Example 2) Pork soup was placed inside and heated in a microwave oven, and the time it took for liquid to start dripping after tipping was measured. Comparing three conventional examples without the under-protrusion 36-stepped rib section 12 structure with three examples with the under-protrusion 36-stepped rib section 12 structure, the conventional examples started dripping in an average of 2 seconds, while the examples did not drip even after 3 minutes. Liquid leakage was completely prevented.

[0066] Similar tests were conducted with Yukgaejang and ginger soup. In the case of Yukgaejang, as with the pork soup, no dripping occurred even after 3 minutes. In the case of ginger soup, there were cases where no dripping occurred after 3 minutes, cases where dripping began at 42 seconds, and cases where dripping began at 14 seconds.

[0067] (Discussion) The leak-inhibiting effect was confirmed even at room temperature without heating. This effect becomes more pronounced when heated in a microwave. It can be inferred that the resin softens when the contents are heated, causing the under projection 36 to deform flexibly in accordance with the inner wall of the container, while the stepped rib portion 12 acts to prevent this elastic deformation from escaping.

[0068] It can be inferred that, not only when heated in a microwave, but also when the contents are hot beverages such as hot coffee, hot pork soup, or hot soup, the under projection 36 will flexibly deform in accordance with the inner wall of the container due to the steam heat, and the stepped rib portion 12 will act to prevent this elastic deformation from escaping.

[0069] ~Variations~ The present invention is not limited to the above embodiments, and various modifications are possible within the scope of the above technical concept.

[0070] Figure 7 shows one modified example. In the above embodiment, the combination of the under projection 36-stepped rib section 12 structure and the stepped projection 37-stepped rib section 15 structure was described, but the effects of the present invention can be obtained with the under projection 36-stepped rib section 12 structure alone. In the illustrated modified example, the stepped projection 37-stepped rib section 15 structure is omitted.

[0071] Figure 8 shows another application example. In the above embodiment, the application to a lid for a circular paper container was described, but the illustrated modification is an example of application to a lid for a rectangular resin container. In other words, it is applicable without being limited by the container shape or container material. Even in the modified example, the airtightness can be improved and liquid leakage can be suppressed. [Explanation of Symbols]

[0072] 1 lid 10 Top surface of the lid 11 Center of the top surface of the lid 12 Stepped rib section 13 Width part 14 Height section 15 Stepped rib section 16 Width part 17 Height section 18 Stepped rib section 19 Stepped rib section 30 Lid fitting section 31 Cover fitting section outer wall 32 Top part of the lid fitting section 33 Inner wall of the lid fitting section 34 Lid fitting space 36 Under-protrusion 37 step protrusion

Claims

1. The top surface of the lid and, The lid fitting portion is provided around the top surface of the lid and fits with a container fitting portion provided at the opening of the container, The lid fitting portion has an outer wall of the lid fitting portion, a top portion of the lid fitting portion, and an inner wall of the lid fitting portion. The lower part of the inner wall of the lid fitting portion is provided with an under projection that protrudes outward in the circumferential direction. The top surface of the lid is provided with a stepped rib portion adjacent to the inner wall of the lid fitting portion. The stepped rib portion consists of a width portion extending horizontally and a height portion extending upward from the end of the width portion. The height of the stepped rib portion corresponds to the position of the under projection. The thickness of the aforementioned under projection is thinner than the thickness of the stepped rib portion. A resin lid.

2. The width of the stepped rib portion is 1 to 3 times the height of the stepped rib portion. A resin lid according to claim 1.

3. The top surface of the lid and, The lid fitting portion is provided around the top surface of the lid and fits with a container fitting portion provided at the opening of the container, The lid fitting portion has an outer wall of the lid fitting portion, a top portion of the lid fitting portion, and an inner wall of the lid fitting portion. The lower part of the inner wall of the lid fitting portion is provided with an under projection that protrudes outward in the circumferential direction. A stepped rib portion is provided on the top surface of the lid. The stepped rib portion comprises a first stepped rib portion and a second stepped rib portion. The first stepped rib portion and the second stepped rib portion each comprise a width portion extending horizontally and a height portion extending upward from the end of the width portion. The first stepped rib portion is provided adjacent to the inner wall of the lid fitting portion, The second stepped rib portion is provided adjacent to the first stepped rib portion, The height of the first stepped rib corresponds to the position of the under projection. The thickness of the aforementioned under projection is thinner than the thickness of the stepped rib portion. A resin lid.

4. The taper angle of the inner wall of the lid fitting portion is equal to the taper angle of the container over which the resin lid is placed. The inner wall of the lid fitting portion is provided with a stepped projection that protrudes circumferentially outward from the upper part of the under projection. The height of the second stepped rib corresponds to the position of the stepped projection. A resin lid according to claim 3.

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