Composite container

Abstract

To provide a composite container that reduces the amount of resin used while offering excellent airtightness when the lid is closed. [Solution] A bottomed cylindrical composite container 1 made primarily of paper and having an opening 5 on its top surface, comprising a resin frame 10 having an annular frame 20 forming the opening 5 and a side frame 30 connected to the annular frame 20, a paper side 60 joined to the annular frame 20 and the side frame 30, and a protrusion 24 provided on the annular frame 20 that can make line contact with the lid C when the lid C is closed.

Description

【Technical Field】 【0001】 The present invention relates to a bottomed cylindrical composite container mainly made of paper and having an opening on the top surface. 【Background Art】 【0002】 In recent years, for the purpose of reducing the environmental load, a reduction in the amount of resin used in containers has been demanded. As such a container, a composite container in which a part of the container is replaced with paper blanks (a laminate including a paper layer and a resin layer) has been proposed (for example, see Patent Document 1). 【0003】 The composite container described in Patent Document 1 is configured by using a resin framework and a paper cylindrical body for the storage part, so that the amount of resin used can be reduced as compared with the case where the entire storage part is made of resin. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Unexamined Patent Application Publication No. 2023 - 081214 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 However, in the composite container of Patent Document 1, when the amount of resin used in the composite container is greatly reduced, when the paper cylindrical body is deformed, the resin framework follows the deformation, so that the opening of the container is distorted (for example, deformed into an elliptical shape), and the roundness of the opening (the difference between the maximum diameter and the minimum diameter) decreases. When the opening of the container is distorted and the roundness decreases, a gap occurs when the lid is closed, resulting in impaired airtightness and a risk of leakage of the contents from the container. 【0006】 The present invention has been made in view of the above problems, and an object thereof is to provide a composite container that has excellent airtightness when the lid is closed while reducing the amount of resin used. [Means for solving the problem] 【0007】 The characteristic configuration of the composite container according to the present invention, which solves the above problems, is A bottomed cylindrical composite container made primarily of paper, with an opening on the top surface, A resin frame having an annular frame portion that forms the opening, and a side frame portion connected to the annular frame portion, The annular skeletal portion and the side skeletal portion are joined to the paper side portion, A protrusion provided on the annular skeletal portion that can make line contact with the lid when the lid is closed and The goal is to provide for it. 【0008】 This composite container configuration includes a resin frame and paper side sections, thus reducing the amount of resin used compared to a container entirely made of resin. Furthermore, reducing the amount of resin used in the annular frame forming the opening allows the annular frame to more easily follow the deformation of the paper side sections. The opening becomes an ellipse shape with the major axis being the straight line connecting the connection points of the annular frame and the side frame sections, resulting in a gap between the lid and the opening when the lid is closed. However, this composite container configuration includes a protrusion on the annular frame that can make line contact with the lid when it is closed. This protrusion and the side of the lid compete when the lid is closed, improving the airtightness between the annular frame and the lid. Therefore, no gap is created between the lid and the opening when the lid is closed, providing a composite container with excellent airtightness. 【0009】 In the composite container according to the present invention, Preferably, the protrusions are formed to extend in the circumferential direction of the annular skeletal portion. 【0010】 In this composite container configuration, the protrusions are formed to extend circumferentially around the annular framework, thus contributing to improved roundness of the opening. Furthermore, when the lid is closed, the protrusions and the sides of the lid compete with each other around the entire circumference of the opening, allowing for a reduction in the amount of resin used while maintaining the roundness of the opening. As a result, a composite container with excellent airtightness when the lid is closed can be provided. 【0011】 In the composite container according to the present invention, Preferably, the protrusion is formed to project inward from the annular skeletal portion. 【0012】 In this composite container configuration, the protrusions are formed to project inward from the annular skeletal structure, so that they come into contact with the outer surface of the inner ring provided on the lid. Therefore, no gaps are created when the lid is closed, providing a composite container with excellent airtightness. 【0013】 In the composite container according to the present invention, It is preferable that the paper conversion rate is 50% or higher. 【0014】 With this composite container configuration, the paper content is 50% or more, which allows for a reduction in the amount of resin used to less than half that of conventional containers. [Brief explanation of the drawing] 【0015】 [Figure 1] Figure 1 shows a perspective view of a composite container according to one embodiment of the present invention, where (a) shows the composite container with a lid attached, and (b) shows the composite container with the lid removed. [Figure 2] Figure 2 shows a plan view and a side view of the composite container. [Figure 3] Figure 3 is a cross-sectional view of the composite container at position AA in Figure 1(a). [Figure 4] Figure 4 is a cross-sectional view of the composite container at position BB in Figure 1(b). [Figure 5] Figure 5 is a plan view of the side and bottom sections of the composite container in its unfolded state before assembly. 【Mode for Carrying Out the Invention】 【0016】 Hereinafter, the present invention will be described with reference to the drawings. However, the present invention is not intended to be limited to the embodiments described below or the configurations shown in the drawings. Regarding the sizes and thicknesses of each part shown in the drawings, they are enlarged as appropriate for ease of explanation and do not strictly reflect the actual size relationships (scale). In the following description, unless otherwise specified, the side where the opening 5 of the composite container 1 is arranged is the "top surface", and the side where the bottom surface portion 60 is arranged is the "bottom surface". 【0017】 <Overall Configuration> FIG. 1 shows a perspective view of a composite container 1 according to an embodiment of the present invention. (a) shows a state where a lid C is attached to the composite container 1, and (b) shows a state where the lid C is removed from the composite container 1. The composite container 1 is a bottomed cylindrical container mainly made of paper and having an opening 5 on the top surface, and the contents are put into the composite container 1 through the opening 5. Here, the main material refers to a material whose proportion in the total material used for the composite container 1 is 50% or more, preferably 70% or more, more preferably 90% or more on a weight basis. In the composite container 1 of this embodiment, it is preferable that the weight ratio of the paper used for the composite container 1 (hereinafter referred to as the "paper ratio") is 50% or more with respect to the total weight of the composite container 1. By having a paper ratio of 50% or more, the amount of resin used can be reduced to less than half of that of conventional containers. 【0018】 As shown in FIG. 1(b), the composite container 1 includes a resin-made skeleton portion 10, and a paper-made side surface portion 50 and bottom surface portion 60. By being configured in this way, the amount of resin used can be reduced as compared with the case where the entire container is made of resin. The composite container 1 is formed by insert molding the side surface portion 50 and the bottom surface portion 60 into the skeleton portion 10. For example, it can be molded by injection molding the skeleton portion 10 in a state where the side surface portion 50 and the bottom surface portion 60 that have been die-cut are accommodated in a molding die. Hereinafter, each configuration included in the composite container 1 will be described in detail. 【0019】 <Skeletal part> As shown in Fig. 1(b), the skeletal part 10 has an annular skeletal part 20, a side skeletal part 30, and a bottom skeletal part 40. The side skeletal part 30 is connected to the annular skeletal part 20 and the bottom skeletal part 40, and the annular skeletal part 20, the side skeletal part 30, and the bottom skeletal part 40 are integrally formed by injection molding. As the material constituting the skeletal part 10, thermoplastic resins such as polyethylene, polypropylene, polyester, and polyamide are preferable. 【0020】 〔Annular skeletal part〕 The annular skeletal part 20 is annular and forms an opening 5. The annular skeletal part 20 has a cylindrical shape and is configured to cover the end face on the top surface side of the side surface part 50. In the present embodiment, the screw part 21, the lip 22, and the reinforcing rib 23 constituting the annular skeletal part 20 are arranged in this order from the top surface side to the bottom surface side. Further, the annular skeletal part 20 is provided with a convex part 24 (see Fig. 4) that can be in line contact with the lid C when the lid C is closed. In the present embodiment, the lid C is attached to the annular skeletal part 20 by screw engagement between the thread 25 of the screw part 21 and the thread (not shown) of the lid C. However, in the annular skeletal part 20, instead of the screw part 21, a convex or concave engaged part may be provided, and the lid C may be configured to be attached by engagement of the concave or convex engaging part provided on the lid C with the engaged part. 【0021】 The lip 22 is annular and protrudes outward. As shown in Fig. 1(a), the top surface side of the lip 22 abuts against the lower end part of the lid C when the lid C is attached to the annular skeletal part 20. Since the lip 22 has an annular shape and protrudes outward, the sectional coefficient can be increased over the entire circumference of the annular skeletal part 20, which contributes to maintaining the roundness of the opening 5. However, when the thickness (axial width) of the lip 22 increases, the amount of resin used increases, and the paper conversion rate of the composite container 1 becomes less than 50%. Therefore, the thickness of the lip 22 is preferably configured to be 0.5 mm to 2 mm. By configuring the thickness of the lip 22 to be 0.5 mm to 2 mm, it is possible to provide the composite container 1 with a paper conversion rate of 50% or more while maintaining the roundness of the opening 5. 【0022】 In the composite container 1, reducing the amount of resin used in the annular skeletal portion 20 that forms the opening 5 makes it easier for the annular skeletal portion 20 to follow the deformation of the paper side portion 50 (from a curved shape when viewed from above to a straight shape), and the opening 5 becomes an elliptical shape with the straight line connecting the connection point between the annular skeletal portion 20 and the side skeletal portion 30 as its major axis, which may reduce its roundness. Also, in the composite container 1, if the thickness of the opening 5 is set to be thin in order to reduce the amount of resin used, sink marks will occur on the back side of the screw threads 25 (the inner surface of the opening 5), and if these sink marks overlap with the part where the lid C and the opening 5 come into contact (sealing point), it will affect the airtightness when the lid C is closed. Therefore, in the present invention, the problem of reduced airtightness due to the reduction in the amount of resin used is solved by providing reinforcing ribs 23 or protrusions 24 in the composite container 1, or by devising the configuration of the screw portion 21. The configurations of the reinforcing ribs 23, protrusions 24, and screw portion 21, which are characteristic of the present invention, will be described in detail below. 【0023】 [Reinforcement ribs] The reinforcing ribs 23 reinforce the annular skeletal portion 20 that forms the opening 5. Because the composite container 1 is equipped with the reinforcing ribs 23, even if the paper side portion 50 attempts to deform from a curved shape to a straight shape due to elastic restoring force when viewed from above, the shape of the annular skeletal portion 20 is maintained against that elastic restoring force, and deformation of the opening 5 can be suppressed. Therefore, by maintaining the roundness of the opening 5, no gap is created between the lid C and the opening 5 when the lid C is closed, and a composite container 1 with excellent airtightness can be provided. 【0024】 Preferably, the reinforcing rib 23 is provided integrally with the lip 22 on the bottom side (lower side) of the lip 22, along the direction in which the lip 22 extends, as shown in Figure 1. By providing the reinforcing rib 23 on the lip 22, deformation of the annular lip 22 can be suppressed. As a result, the roundness of the opening 5 is maintained, and a composite container 1 with excellent airtightness when the lid C is closed can be provided. 【0025】 The reinforcing ribs 23 are preferably provided near the connection point between the annular frame portion 20 and the side frame portion 30, as shown in Figure 1. The reinforcing ribs 23 are provided near the connection point between the annular frame portion 20 and the side frame portion 30, which are particularly prone to deformation, because the elastic restoring force of the side portion 50 is strongest thereon. This ensures that the roundness of the opening 5 is maintained while reducing the amount of resin used, and a composite container 1 with excellent airtightness when the lid C is closed can be provided. 【0026】 Figure 2 shows a plan view and a side view of the composite container 1. In the plan view of Figure 2, the screw threads 25 and the bottom frame portion 40 are omitted, and the overlapping portion of the lip 22 and the reinforcing rib 23 is shown in black. As shown in the plan view of Figure 2, when viewed from above, it is preferable that the reinforcing rib 23 is provided in an angular region R of ±1 to 5° from the center O of the annular frame portion 20, with reference to the straight line connecting the center O of the annular frame portion 20 and the connection point P between the annular frame portion 20 and the side frame portion 30. By providing the reinforcing rib 23 in an angular region R of ±1 to 5°, it is possible to effectively reinforce the area near the connection point between the annular frame portion 20 and the side frame portion 30, which is particularly prone to deformation, while suppressing the increase in the amount of resin due to the provision of the reinforcing rib 23. If the angular region R in which the reinforcing rib 23 is provided is greater than ±5°, the amount of resin used will increase, and the paper content of the composite container 1 will fall below 50%. Furthermore, if the angular region R in which the reinforcing ribs 23 are provided becomes smaller than ±1°, the effect of reinforcing the annular frame portion 20 is not sufficiently obtained, and the roundness of the opening 5 decreases. 【0027】 [Convex part] Figure 3 is a cross-sectional view of the composite container 1 at position AA in Figure 1(a). The protrusion 24 is provided on the annular frame 20 so that it can make line contact with the lid C when the lid C of the composite container 1 is closed. By providing the protrusion 24, when the lid C is closed, the protrusion 24 and the side surface of the lid C compete with each other, improving the airtightness between the annular frame 20 and the lid C. Therefore, when the lid C is closed, no gap is created between the lid C and the opening 5, and a composite container 1 with excellent airtightness can be provided. The protrusion L of the protrusion 24 (amount of protrusion from the inner circumferential surface of the annular frame 20) is preferably 0.01 mm to 0.5 mm, and more preferably 0.05 mm to 0.1 mm. If the protrusion L of the protrusion 24 is greater than 0.5 mm, molding defects will occur during insert molding. Furthermore, if the protrusion L of the protrusion 24 becomes smaller than 0.01 mm, the protrusion 24 and the side surface of the lid C will not come into contact, which may impair airtightness. 【0028】 It is preferable that the protrusions 24 are formed to extend in the circumferential direction of the annular skeleton portion 20. By forming the protrusions 24 to extend in the circumferential direction of the annular skeleton portion 20, the protrusions 24 contribute to improving the roundness of the opening 5. Furthermore, when the lid C is closed, the protrusions 24 and the side surface of the lid C compete with each other around the entire circumference of the opening 5, so that the amount of resin used can be reduced while maintaining the roundness of the opening 5. As a result, a composite container 1 with excellent airtightness when the lid C is closed can be provided. 【0029】 The protrusion 24 is preferably formed to protrude inward from the annular skeletal portion 20, as shown in Figure 3. By forming the protrusion 24 to protrude inward from the annular skeletal portion 20, the outer surface of the inner ring I provided on the lid C comes into contact with the protrusion 24. Therefore, no gap is created when the lid C is closed, and a composite container 1 with excellent airtightness can be provided. 【0030】 [Screw part] Figure 4 is a cross-sectional view of the composite container 1 at position BB in Figure 1(b). The threaded portion 21 has outwardly projecting threads 25 formed at a predetermined pitch W. As shown in Figure 4, the relationship between the thickness X of the threads 25 in the lead direction and the thickness Y of the opening 5 is given by the following equation (1): X ≤ Y ···(1) If the conditions are met, sink marks are less likely to occur on the back side of the screw threads 25. Also, as shown in Figure 1(b), since the threading start position S of the screw threads 25 is set a certain distance away from the end of the opening 5, even if sink marks occur on the back side of the screw threads 25, when the lid C is closed, the sink marks will not overlap with the sealing point. Furthermore, as shown in Figure 4, since the top side of the screw threads 25 is cut flat, the amount of resin in the screw threads 25 is reduced, a flat portion 25a is formed on the screw threads 25, and the flat portion 25a and the screw threads 25 formed on the lid C make at least line contact, enabling stable capping. As a result, when the lid C is closed, no gap is created between the lid C and the opening 5, and a composite container 1 with excellent airtightness can be provided. Note that "thickness of the opening 5" is, in other words, the radial thickness of the screw portion 21 in the part where the protrusion 24 and screw threads 25 are not provided. 【0031】 In this embodiment, in addition to satisfying the relationship of equation (1) above, as shown in Figure 4, the relationship between the distance Z from the end of the opening 5 (upper end of the threaded portion 21) to the threading start position S and the pitch W of the thread 25 (distance between adjacent threads 25 in Figure 4) is given by the following equation (2): W ≤ Z ···(2) It is preferable that the following conditions are met. The relationship between the distance Z from the end of the opening 5 to the threading start position S and the pitch W of the thread 25 satisfies the above equation (2), so that a sealing point can be set between the end of the opening 5 and the threading start position S. As a result, even if sink marks occur on the back side of the thread 25, when the lid C is closed, the sink marks do not overlap with the sealing point, so a composite container 1 with excellent airtightness when the lid C is closed can be provided. 【0032】 The threaded portion 21 is preferably a multi-start thread. Having a multi-start thread in the threaded portion 21 allows the lid C to be closed with fewer rotations, and even when the lid C is closed with fewer rotations, a composite container 1 with excellent airtightness can be provided. Furthermore, in this embodiment, since the threads 25 are intermittent threads (skipping threads) provided intermittently in the circumferential direction, resin is not required in the intermittent portions, thus reducing the amount of resin in the threads 25. 【0033】 [Side frame section] The side frame portion 30 is formed in a columnar shape, with one end (upper end) connected to the annular frame portion 20 and the other end (lower end) connected to the bottom frame portion 40. In this embodiment, two side frame portions 30 are provided at opposing positions, joining the lateral end faces of the side portion 50. 【0034】 The side frame portion 30 has a linear projection 30a formed to extend in the vertical direction and a plate portion 30b provided on the inner surface of the composite container 1. The linear projection 30a is arranged so that it can abut the circumferential ends of the side portion 50. In this embodiment, a reinforcing rib 23 is provided at the position where the linear projection 30a and the lip 22 intersect. In this way, the interaction of the lip 22, the reinforcing rib 23, and the linear projection 30a makes it possible to more reliably maintain the shape of the annular frame portion 20. 【0035】 [Bottom frame] As shown in Figure 1(b), the bottom frame 40 has a hollow disc-shaped disc portion 41 and a bottom reinforcement portion 42. The bottom frame 40 is positioned to have the same central axis as the annular frame 20 and is connected to the side frame 30. The disc portion 41 joins the bottom-side end face of the side frame 50 to the end face of the outer periphery of the bottom frame 60. The bottom reinforcement portion 42 is provided to connect the vicinity of the connection point between the disc portion 41 and the side frame 30, passing through the center of the disc portion 41 to the vicinity of the connection point between the opposing disc portion 41 and the side frame 30. 【0036】 <Side part / bottom part> The side sections 50 and bottom section 60 are die-cut from paper blanks, which are laminates containing a paper layer and a resin layer. The paper blanks used for the side sections 50 and bottom section 60 consist of five layers, arranged in order from the outside of the composite container 1: an outer resin coating layer, a paper layer, an adhesive resin layer (adhesive layer), a gas barrier layer, and an inner resin coating layer. The paper blanks may also have other layers, such as a toughening layer and a printing ink layer. 【0037】 Figure 5 is a plan view of the side portion 50 and bottom portion 60 of the composite container 1 in its unfolded state before assembly. The side portion 50 has a first side portion 51 and a second side portion 52 and is formed in a substantially rectangular shape. As shown in Figure 5, the first side portion 51 is connected to both ends of the substantially circular bottom portion 60 via valley fold lines 71, and the second side portion 52 is connected via valley fold lines 72. In addition, cutting lines 73 and 74 are formed at the boundaries between the bottom portion 60 and the first side portion 51 and the second side portion 52. 【0038】 Although the composite container of the present invention has been described above based on embodiments, the present invention is not limited to the configuration described in the above embodiments, and its configuration can be modified as appropriate without departing from the spirit of the invention. [Industrial applicability] 【0039】 Because the composite container of the present invention has excellent airtightness when the lid is closed, it can be used as a container for storing easily flowing contents such as powders, liquids, and semi-solids. [Explanation of Symbols] 【0040】 1. Composite container 5 Openings 10 Skeletal parts 20 Annular skeletal part 21 Threaded part 22 Lip 23 Reinforcement Ribs 24 Convex part 25 threads 30 Side frame section 40 Bottom frame 50 Side part O Center of the annular skeletal structure P is the connection point between the annular skeletal section and the lateral skeletal section. R angle area S Thread cutting start position

Claims

[Claim 1] A bottomed cylindrical composite container made primarily of paper, with an opening on the top surface, A resin frame having an annular frame portion that forms the opening, and a side frame portion connected to the annular frame portion, The annular skeletal portion and the side skeletal portion are joined to the paper side portion, A protrusion provided on the annular skeletal portion that can make line contact with the lid when the lid is closed and A composite container equipped with [specific features / features]. [Claim 2] The composite container according to claim 1, wherein the protrusion is formed to extend in the circumferential direction of the annular skeletal portion. [Claim 3] The composite container according to claim 1, wherein the convex portion is formed to protrude inward from the annular skeletal portion. [Claim 4] A composite container according to any one of claims 1 to 3, wherein the paper conversion rate is 50% or more.

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