Lid and packaging container

Abstract

To provide a lid that can be suitably combined with a paper container body even if environmental measures are taken.SOLUTION: A lid 50, to be attached by fitting to an opening of a paper container body 10, has a plugging force to a synthetic resin jig having the same dimension as a set dimension of the container body 10 of equal to or smaller than 220 newton and a detaching force from the jig of equal to or greater than 15 newton and equal to or smaller than 25 newton.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a lid, more particularly to a lid to be attached to a paper container body, and also to a packaging container using the lid. [Background technology]

[0002] Packaging containers having a plastic lid attached to the opening of a container body mainly made of paper are widely used for powder contents such as detergents and bath additives (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-54537 A Summary of the Invention [Problem to be solved by the invention]

[0004] Efforts are being made to reduce the environmental impact of various packaging containers, including plastics. One such effort is to use plastics made from plant-based raw materials to make the container body and lid.

[0005] In the case of a packaging container as described in Patent Document 1, since the container body is made of paper, the main target in terms of environmental friendliness is the lid. The inventors discovered a unique situation that arises when combining a lid with a paper container body in order to reduce the environmental impact of the lid, and completed the present invention by addressing this situation.

[0006] An object of the present invention is to provide a lid that can be suitably combined with a paper container body while being environmentally friendly. [Means for solving the problem]

[0007] A first aspect of the present invention is a lid that is attached by fitting to the opening of a paper container body. This lid has a plugging force of 220 Newtons or less when applied to a jig made of synthetic resin having the same dimensions as the set dimensions of the container body, and a removal force of 15 Newtons to 25 Newtons when applied to the jig.

[0008] A second aspect of the present invention is a packaging container comprising a lid body relating to the first aspect and a paper container body having set dimensions identical to the dimensions of the jig and an opening, wherein the lid body is attached to the container body so as to cover the opening. Effect of the Invention

[0009] According to the present invention, a lid body can be provided that can be suitably combined with a paper container body while being environmentally friendly. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a packaging container according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view of the packaging container. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view of a packaging container 1 according to this embodiment. The packaging container 1 includes a container body 10 and a lid body 50 attached to the container body 10. The shape of the container body 10 in this embodiment is a cylinder with a bottom, but is not particularly limited, and may be other shapes as long as it has an opening and can accommodate the contents. The lid body 50 covers the opening of the container body 10.

[0012] FIG. 2 shows a schematic cross-sectional view of the packaging container 1. The container body 10 has a cylindrical side surface portion 11 and a substantially disk-shaped bottom surface portion 12 . The container body 10 is mainly made of paper. Various types of paper can be used taking into consideration the contents and the environment in which it will be used. If necessary, printing may be added to provide various indications, or a resin layer that provides waterproofing may be added.

[0013] The lower end of the side portion 11 is folded inward over the entire circumference of the cylindrical shape. The periphery of the bottom portion 12 is folded downward over the entire circumference, and the side portion 11 and the bottom portion 12 are joined together with the folded periphery inserted between the folded inward side portions 11. An example of a joining method is joining with an adhesive, and if the side portion 11 and the bottom portion 12 have a resin layer, joining by heat fusion is also possible. The upper end of the side surface 11 is folded back outward over the entire circumference of the cylindrical shape, so that the container body 10 has an opening 13 at the top capable of accommodating the contents, and a curl flange 14 that can be engaged with the lid 50 is formed around the periphery of the opening 13.

[0014] The lid body 50 is a member having a generally circular shape in a plan view, and has a peripheral edge extending in one direction in the thickness direction, so that the lid body 50 has an engagement portion 51 that engages with the container body 10 on the peripheral edge in a plan view. The planar shape of the lid 50 is not limited to a circle, and can be determined appropriately based on the shape of the opening of the container body, etc. Similarly, the form of the engagement portion 51 can also be determined appropriately, and the lid may have a protrusion or rib that protrudes inward in a planar view.

[0015] For lids to be attached to paper container bodies, it is difficult to use the commonly used screw thread fitting method. Therefore, a method called "stoppering" is often used, in which the lid is fitted by applying force from above. The lid 50 attached by stoppering is supported on the container body 10 by frictional engagement or mechanical engagement that occurs between the engagement part 51 and the container body 10.

[0016] When the inventors created lids from biomass-derived plastics to be attached to paper container bodies in order to make them more environmentally friendly, they found that the lids did not fit adequately into the container bodies in many cases. This was presumed to be due to the increased force (hereinafter referred to as "stopping force") required to adequately fit the lids into the container bodies during the stoppering process compared to before the change in plastic. Therefore, the settings of the capping device were changed to increase the capping force. While this reduced the number of cases of insufficient fitting, the amount of force required to remove the fitted lid from the container (hereinafter referred to as the "removal force") increased, resulting in a problem of reduced usability as a container.

[0017] The inventors conducted research to solve the above problem, and found that it was difficult to set an appropriate capping force when using container bodies that were actually used. The reason for this was that the dimensional variation of paper container bodies was significantly larger than that of container bodies made of resin or the like.

[0018] For this reason, the inventors have constructed an evaluation system that can stably evaluate the capping force and removal force. The details will be described later using experimental examples, but based on this, the inventors have evaluated the capping force and removal force of caps made of various resins.

[0019] The lid 50 according to this embodiment, which was completed based on the above, has a capping force of 220 Newtons (N) or less and a removal force of 15 to 25 N, both measured by the above evaluation system. This ensures that even when combined with a paper container body 10, which has large dimensional variations, the capping force is not excessively large and the removal force is not excessively large either.

[0020] Furthermore, it was also confirmed that such a lid 50 can be produced by mixing a base resin having a flexural modulus of 400 megapascals (MPa) or more with a sub-resin having a flexural modulus of 250 MPa or less. In the present invention, the flexural modulus of each resin is a value measured in accordance with JIS K 7171 using a test piece consisting of the respective resin alone. The types and ratios of the base resin and sub resin in the lid 50 can be identified by measurement using a differential scanning calorimeter (DSC).

[0021] The base resin is typically linear low density polyethylene (LLDPE), but low density polyethylene (LDPE) can also be used. The density of LLDPE is 0.940 g / cm 3 It is preferable that it is less than 1000 .mu.m. The mass ratio of the base resin in the lid 50 needs only to exceed 50%, and is preferably 70% or more.

[0022] The sub-resin is typically LDPE, but LLDPE etc. can also be used. The density of LDPE is 0.925g / cm 3 It is preferable that it is less than 1000 .mu.m.

[0023] The effects of the lid according to this embodiment will be further described using experimental examples. The technical scope of the present invention is not limited in any way by the specific contents of each experimental example.

[0024] The materials used in each experimental example are shown below. (Base resin) LLDPE1: Flexural modulus 510MPa (Prime Polymer 40300J, density 0.938g / cm 3 ) LLDPE2: Flexural modulus 190MPa (Prime Polymer 20200J, density 0.919g / cm 3 ) LLDPE3: Flexural modulus 390MPa (Tosoh M70, density 0.936g / cm 3 )

[0025] (Sub resin) LDPE1: Flexural modulus 150MPa (Braskem's plant-derived polyethylene SPB608, density 0.915g / cm 3 ) LDPE2: Flexural modulus 250MPa (Braskem's plant-derived polyethylene SPB208, density 0.923g / cm 3 ) LDPE3: Bending modulus of elasticity 190MPa (petroleum-derived polyethylene LJ920 manufactured by Japan Polyethylene Co., Ltd., density 0.923g / cm 3 )

[0026] The lids of the same shape and size for each experimental example were produced by injection molding using a resin composition obtained by mixing the base resin and the sub resin in the ratio shown in Table 1. The number of samples for each experimental example was 80. The cover is circular in plan view, with an engaging portion extending downwards by 11 mm from its periphery. An annular rib protrudes from the inner surface of the engaging portion.

[0027] [Table 1]

[0028] The plugging force and withdrawal force were measured as follows. First, a jig made of synthetic resin with the same dimensions as the set dimensions of the container body to be applied is prepared. The jig in this study is a solid cylinder made of ABS resin, and has a protrusion on the outer circumferential surface of one end in the axial direction, similar to the curl flange of the container body.

[0029] The prepared jig was set in a Tensilon series testing machine, and the lids of each example, which had been chucked and aligned, were pushed from above at 100 mm / min until they were completely fitted into the jig. The maximum force measured at this time was taken as the capping force, and the arithmetic mean value of the 80 samples was used as the capping force for each example. Next, while supporting the jig, the lid was lifted upward again and removed from the jig. The maximum force measured at this time was taken as the removal force, and the arithmetic mean value was used as the removal force for each example.

[0030] In addition, 80 paper containers manufactured to the same set dimensions as the jig were capped using the capping device, and the capping success rate was recorded. Capping was performed with a constant load regardless of the measured capping force for each example. Next, the lids of the samples that were successfully stoppered were held up by a suction cup for 10 seconds, and the number of samples in which the container body fell off the lid during that time was recorded. The results of each study are shown in Table 1.

[0031] The following can be read from the results of each evaluation shown in Table 1. By setting the capping force in the measurement according to this embodiment using the above jig to 220 N or less, failure in capping the paper container body can be prevented and capping can be performed efficiently. By setting the capping force to 15 N or more in the measurement according to this embodiment using the above jig, it is possible to preferably prevent the cap from falling off when the capped cap is held and lifted. A lid having such favorable plugging and removal forces can be realized by molding a material that is an appropriate mixture of a base resin with a flexural modulus of 400 MPa or more and a sub-resin with a flexural modulus of 250 MPa or less. The total flexural modulus of the lid having suitable plugging and removal forces is generally between 400 and 480 MPa. The flexural modulus may be an actual measurement value using the mixed resin that constitutes the lid, but it may also be an "estimated flexural modulus" which is the average value of the flexural modulus calculated based on the flexural modulus and content of the base resin and sub resin in the mixed resin. Table 1 shows the estimated flexural modulus for each experimental example.

[0032] As described above, by applying the lid body according to this embodiment to a paper container body, a packaging container that is easy to manufacture and has a good usability can be formed. Furthermore, up to 30% plant-based plastic can be used as a sub-resin, and this can be effectively applied to the container body, including bio-PET, allowing the packaging container to be highly environmentally friendly.

[0033] The above describes one embodiment of the present invention, including experimental examples. However, the specific configuration is not limited to this embodiment, and changes and combinations of the configuration within the scope of the gist of the present invention are also included. [Explanation of symbols]

[0034] 1 Packaging container 10 Container body 50 Lid

Claims

1. A lid body that is attached to the opening of a paper container body by fitting, The capping force against a synthetic resin jig having the same dimensions as the set dimensions of the container body is 220 Newtons or less, and the removal force against the jig is 15 Newtons to 25 Newtons. Lid body.

2. Contains a base resin having a flexural modulus of 400 megapascals or more and a sub-resin having a flexural modulus of 250 megapascals or less. The lid according to claim 1 .

3. The base resin is contained in an amount of 70% or more, The sub-resin is contained in an amount of 10% or more and 30% or less. The lid according to claim 2.

4. The sub resin is a low density polyethylene; The lid according to claim 2.

5. The low density polyethylene is derived from biomass; The lid according to claim 4.

6. The base resin is a linear low-density polyethylene. The lid according to claim 2.

7. The flexural modulus is 400 MPa or more and 480 MPa or less. The lid according to claim 1 .

8. A lid body according to any one of claims 1 to 7, A paper container body having the same set dimensions as the dimensions of the jig and having an opening; Equipped with The lid is attached to the container body so as to cover the opening. packaging container.

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