Lidded paper cup with resealing function

Abstract

To securely expose an adhesive layer (re-sealing layer) when a lid material is peeled off from a paper cup without paper peeling.SOLUTION: A lidded paper cup comprises a paper cup body which comprises a trunk part 11 and a bottom part closing a lower end of the trunk part 11, and has a flange part formed at an upper end part of the trunk part 11, and a lid material 20 which is bonded to a top surface of the flange part to close an upper-end opening of the trunk part 11. The trunk part 11 consists of a low-density polyethylene layer 11d, a linear low-density polyethylene layer 11c, a paper layer 11a, and a low-density polyethylene layer 11b from its inner side face to its outer side face. The lid material 20 comprises a seal layer 20e used for initial adhesion to the top surface of the flange part, and an adhesion layer 20c laminated on an inner layer side of the seal layer 20e and exposed to the outside when the lid material 20 is peeled off from the top surface of the flange part.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a paper cup with a lid that has a resealing function. [Background technology]

[0002] Patent Document 1 discloses a paper cup for filling yogurt. The paper cup is made of polyethylene-coated paper, which is paper (cup base paper) coated with low-density polyethylene. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-192083 A

[0004] The opening of a paper cup made of polyethylene-coated paper is closed by heat-welding a lid to the top of the cup. If polyethylene-coated paper, which is paper coated with low-density polyethylene, is used for the paper cup, when the lid is peeled off, the paper on the paper cup side may peel off and stick to the back of the lid (paper peeling).

[0005] There is a demand for a lid material that closes the opening of a paper cup to have a resealing function. In this case, the lid material is provided with a sealing layer and an adhesive layer so that the opening of a paper cup that has been opened once by peeling off the lid material can be closed again with the lid material. In the initial state (when shipped from the factory), the sealing layer bonds the paper cup and the lid material together to close the cup opening. By making the adhesive layer, which is the inner layer of the sealing layer, exposed to the outside when the lid material is peeled off, the cup opening can be reclosed with the lid material using the exposed adhesive layer instead of the sealing layer.

[0006] However, when the above-mentioned peeling of the paper cup occurs, the peeled paper of the paper cup sticks to the lid, and the adhesive layer is no longer exposed. In other words, the peeled part cannot be reattached to the lid and resealed.

[0007] The above-mentioned "paper peeling" will be explained in an easy-to-understand manner with reference to Figures 5 and 6. Figure 5 is a cross-sectional view showing the state of a lid material 50 and a paper cup 60 in the prior art before opening. Figure 6 is a cross-sectional view showing the state where paper peeling occurs when the lid material 50 is peeled off. In Figures 5 and 6, the thicknesses of the multiple layers that make up the lid material 50 and the paper cup 60 are depicted with considerable emphasis.

[0008] 5, the paper cup 60 is constructed by laminating low-density polyethylene layers 62, 63 on both sides of a paper layer 61. The lid material 50 is constructed by laminating a film composed of a surface resin layer 52, an adhesive layer (resealing layer) 53, a peeling layer 54 and a sealing layer 55 on the base material layer 51 via an adhesive layer (not shown). The opening of the paper cup 60 is closed by the lid material 50 as the lid material 50 is sealed to the edge of the opening of the paper cup 60. In the initial state (before opening), the low-density polyethylene layer 62 of the paper cup 60 in contact with the lid material 50 and the sealing layer 55 of the lid material 50 are heat-sealed.

[0009] Paper peeling occurs when, when the lid material 50 is peeled off from the paper cup 60, separation (tearing) occurs in the paper layer 61 of the paper cup 60 without separation occurring between the adhesive layer 53 and the release layer 54 of the lid material 50. Referring to Figure 6, when paper peeling occurs, the adhesive layer 53 of the lid material 50 is not exposed at that location, and therefore, at the location where the paper peeling occurred, it becomes impossible to reseal the cup opening using the adhesive layer 53. Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention is to ensure that the adhesive layer (resealing layer) is exposed when the lid material is peeled off from the paper cup without causing the paper to peel off.

[0011] The paper cup with a lid and resealing function according to this invention comprises a paper cup body having a cylindrical body and a bottom which closes the lower end of the body, and at the upper end of the body a flange portion is formed by folding the upper end of the body outward, and a lid material which is adhered to the upper surface of the flange portion and closes the upper end opening of the body, the body being composed, from its inner surface to its outer surface, of a low-density polyethylene layer, a linear low-density polyethylene layer and a paper layer, and the lid material is characterized in that it has a sealing layer used for initial adhesion to the upper surface of the flange portion and an adhesive layer which is laminated on the inner side of the sealing layer and which is exposed to the outside when the lid material is peeled off from the upper surface of the flange portion.

[0012] The paper cup with lid according to the present invention comprises a paper cup body and a lid material. The top end of the paper cup body is open, and the top opening is closed by the lid material. To make it easier to attach the lid material, the top end of the body of the paper cup body is folded outward to form a flange. The flange may be formed by simply folding the top end of the body outward, or it may be formed by rolling (curling) the top end of the body outward. The curled part may also be flattened by performing flange pressing processing, which crushes the curled part from above and below. In either case, the flange is formed around the top opening of the body, and the top opening of the body is closed by attaching the lid to the top surface of this flange.

[0013] The upper end of the body is folded or rolled outward, so that the inside (inner surface) of the body reaches the upper surface of the flange. In other words, in the flange, the low-density polyethylene layer, the linear low-density polyethylene layer, and the paper layer are arranged in this order from the upper surface side to the lower surface side, and the low-density polyethylene layer comes into contact with the lid material.

[0014] According to this invention, a linear low-density polyethylene layer is laminated between the low-density polyethylene layer and the paper layer that constitute the barrel of the paper cup body. The linear low-density polyethylene layer stretches when pulled (it has a high tensile elongation rate), and this stretching makes it difficult for the laminated structure of the paper cup body (flange portion) to be destroyed when the lid is peeled off, and makes it easier for the laminated structure of the lid to be destroyed before the paper cup body (flange portion) is destroyed when the lid is peeled off.

[0015] According to this invention, when the lid material is peeled off, the sealing layer of the lid material adhered to the upper surface of the flange peels off, and the adhesive layer laminated on the inner side of the sealing layer is exposed to the outside. The exposed adhesive layer can be used to reseal the lid material. The peeled off sealing layer of the lid material remains adhered to the paper cup body (flange portion).

[0016] Preferably, the thickness of the linear low-density polyethylene layer is 10 to 30 μm. When the thickness of the linear low-density polyethylene layer is thin, the paper layer of the flange portion is prevented from peeling off and sticking to the lid material when the lid material is peeled off (paper peeling), preventing exposure of the adhesive layer of the lid material from being hindered by the paper layer, and when the thickness of the linear low-density polyethylene layer is thick, the linear low-density polyethylene layer is prevented from peeling off and sticking to the lid material, preventing exposure of the adhesive layer of the lid material from being hindered by the linear low-density polyethylene layer.

[0017] In one embodiment, a release layer is laminated between the seal layer and the adhesive layer of the lid material, which makes it easier to expose the adhesive layer when the lid material is peeled off.

[0018] Preferably, a low-density polyethylene layer is laminated on the outer surface of the paper layer of the body, which can protect the outer surface of the paper layer. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a perspective view of a paper cup with a lid. [Diagram 2] 2 is a cross-sectional view of the paper cup with a lid taken along line II-II in FIG. 1. [Diagram 3] 4 is a partially enlarged cross-sectional view showing how the lid material and the paper cup body that constitute the paper cup with lid are bonded together. FIG. [Figure 4] 4 is a partially enlarged cross-sectional view equivalent to FIG. 3, illustrating a state in which a lid is being peeled off from a paper cup with a lid. [Diagram 5] 1 is a partially enlarged cross-sectional view showing how a lid and a paper cup that constitute a conventional paper cup with a lid are bonded together. [Figure 6] 6 is a cross-sectional view equivalent to FIG. 5 showing the state in which paper peeling occurs. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Fig. 1 is a perspective view of a paper cup with a lid. Fig. 2 is a cross-sectional view of the paper cup with a lid taken along line II-II in Fig. 1.

[0021] The paper cup with lid 1 has a bottomed paper cup body 10 consisting of a body 11 and a bottom 12, with the top opening closed by a lid material 20. The body 11 has a large top opening, narrows slightly towards the bottom, and has a roughly rectangular cylindrical shape with rounded corners. When viewed from above, the paper cup body 10 is almost a square with rounded corners. The shape of the body 11 is not limited to a rectangular cylinder, and may be a cylinder, a triangular cylinder, a pentagonal cylinder, or any other polygonal cylinder.

[0022] A flange portion 11A that protrudes outward (to the side) slightly around the entire circumference of the opening periphery (upper edge) of the body 11 of the paper cup body 10 is formed integrally with the paper cup body 10 (body 11). The upper surface of the flange portion 11A is formed flat, and the lid material 20 is bonded to the upper surface of the flange portion 11A.

[0023] The upper peripheral edge of the body 11 of the paper cup body 10 is rolled outward (curled portion), and the flange portion 11A is formed by crushing the curled portion. The bottom 12 is rectangular, and its peripheral edge is bent downward to stand (standing molded portion 12A). The bottom 12 fits snugly into the bottom opening of the body 11, and the lower end of the body 11 is folded inward (folded portion 11B), and this folded portion 11B sandwiches the standing molded portion 12A of the bottom 12. The inner and outer surfaces of the standing molded portion 12A of the bottom 12 are bonded or welded to the inner surfaces of the lower end of the body 11 and the folded portion 11B which sandwich it, and the lower opening of the body 11 is tightly closed by the bottom 12.

[0024] 3 shows how the lid material 20 is adhered to the sheet that constitutes the body 11 (flange portion 11A) of the paper cup body 10. As described above, the flange portion 11A is formed by curling the upper peripheral edge of the body 11 outward, so that the sheet surface that faces the inside (inner surface) of the body 11 of the paper cup body 10 faces upward in the flange portion 11A and faces the lid material 20.

[0025] The sheet constituting the body 11 is composed of a paper layer 11a, a low-density polyethylene layer 11b laminated on the outer side of the paper layer 11a, a linear low-density polyethylene layer 11c laminated on the inner side of the paper layer 11a, and a low-density polyethylene layer 11d laminated on the inner side of the linear low-density polyethylene layer 11c. The low-density polyethylene layer 11b on the outer side of the paper layer 11a is preferably laminated to protect the paper layer 11a, but is not necessarily required and lamination may be omitted.

[0026] Low-density polyethylene is a high-pressure ethylene homopolymer that can be obtained by a conventionally known high-pressure radical polymerization method. Linear low-density polyethylene is a copolymer of ethylene and an α-olefin polymerized using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst. Low-density polyethylene includes those with a density of 0.900 g / cm3. 3 More than 0.940g / cm 3For linear low density polyethylene, a polyethylene having a density of 0.900 g / cm3 or less can be used. 3 More than 0.940g / cm 3 Less than 100 mm of polyethylene can be used.

[0027] An anchor coat layer may be interposed between the paper layer 11a and the linear low-density polyethylene 11c. The anchor coat layer is formed, for example, by an anchor coat agent. Examples of anchor coat agents include polyurethane-based, polyolefin-based, polyethyleneimine-based, and epoxy resin-based anchor coat agents. One example of an anchor coat agent is a two-component curing resin made of polyurethane obtained by the reaction of a polyol base agent and a polyisocyanate curing agent.

[0028] The lid material 20 is formed by laminating a PE sealant film, which is a laminate of a surface resin layer 20b (such as a thermoplastic resin), an adhesive layer (resealing layer) 20c (such as a thermoplastic elastomer and a tackifier resin), a peeling layer 20d (such as a thermoplastic resin), and a sealing layer 20e (such as a PE (polyethylene) heat seal resin), on a base layer 20a (such as PET (polyethylene terephthalate)) via an adhesive layer (not shown). The sealing layer 20e of the PE sealant film faces the body 11 (the upper surface of the flange portion 11A) of the paper cup body 10. For the PE sealant film, for example, a co-extruded multilayer film (Diamilon (registered trademark)) manufactured by Mitsubishi Chemical Corporation can be used. The stacking order of the PE sealant film is not limited to the above-mentioned order, and may be the surface resin layer 20b, the peeling layer 20d, the adhesive layer 20c, and the sealing layer 20e.

[0029] Examples of thermoplastic resins used for the surface resin layer 20b include olefin resins (ethylene resins, propylene resins, cyclic olefin resins, etc.), amide resins, saponified ethylene-vinyl acetate copolymers, ester resins, styrene resins, carbonate resins, etc. There are no limitations on the type of resin as long as the adhesive strength with the adjacent layer is designed to be stronger than the adhesive strength between the release layer 20d and the adhesive layer 20c.

[0030] Examples of the thermoplastic elastomer used in the adhesive layer (resealing layer) 20c include ethylene-based elastomers, propylene-based elastomers, butene-based elastomers, and styrene-based elastomers. Examples of the tackifier resin used in the adhesive layer 20c include rosin-based resins such as natural resin rosin, polymerized rosin, hydrogenated rosin, glycerin ester rosin, and pentaerythritol, terpene-based resins such as terpene, aromatic modified terpene, terpene phenol, and hydrogenated terpene, petroleum resins such as aliphatic petroleum resins, aromatic petroleum resins, and hydrogenated alicyclic petroleum resins, polybutadiene that is liquid at room temperature, polyisoprene that is liquid at room temperature, and polyisobutylene that is liquid at room temperature.

[0031] Thermoplastic resins used for the peeling layer 20d include olefin-based resins (ethylene-based resins, propylene-based resins, cyclic olefin-based resins, etc.), ionomers, amide-based resins, saponified ethylene-vinyl acetate copolymers, ester-based resins, styrene-based resins, carbonate-based resins, etc.

[0032] Examples of the polyethylene heat seal resin used in the seal layer 20e include olefin resins such as low density polyethylene and linear low density polyethylene.

[0033] By heating the low-density polyethylene layer 11d of the body 11 (flange portion 11A) and the sealing layer (polyethylene heat seal resin) 20e of the lid material 20, they are thermally welded together, the lid material 20 is relatively firmly attached to the paper cup body 10, and the upper opening of the body 11 of the paper cup body 10 is tightly closed.

[0034] Referring to FIG. 4, when the lid material 20 is turned up and peeled off, separation does not occur at the boundary between the lid material 20 and the paper cup body 10 (i.e., between the low-density polyethylene layer 11d of the body 11 (flange portion 11A) and the sealing layer 20e of the lid material 20), but occurs between the adhesive layer 20c and the peeling layer 20d of the lid material 20. The peeling layer 20d and sealing layer 20e of the lid material 20 remain attached to the body 11 (flange portion 11A) of the paper cup body 10, and the base layer 20a, surface resin layer 20b and adhesive layer 20c are turned up. By causing separation between the adhesive layer 20c and the peeling layer 20d of the lid material 20, the adhesive layer 20c that is pre-laminated on the inner layer side of the sealing layer 20e in the turned-up lid material 20 is exposed to the outside. The exposed adhesive layer 20c can be used to re-adhere the lid 20 to the body 11 (the upper surface of the flange 11A) (reseal).

[0035] The linear low-density polyethylene layer 11c laminated between the paper layer 11a and the low-density polyethylene layer 11d constituting the body 11 of the paper cup body 10 is prone to elongation. It is believed that the laminated structure of the body 11 (flange portion 11A) is less likely to be destroyed due to the elongation that occurs in the linear low-density polyethylene layer 11c when the lid material 20 is turned up and peeled off. It is also believed that the laminated structure of the lid material 20 is more likely to be destroyed (separated between the adhesive layer 20c and the peel layer 20d) than the body 11 (flange portion 11A) when the lid material 20 is peeled off.

[0036] Examples and comparative examples will be described below. EXAMPLES

[0037] Basis weight 320g / m 2 A base paper is prepared, and its coated surface is subjected to corona discharge treatment and anchor coat treatment in that order. Molten low-density polyethylene (Novatec LC520, manufactured by Japan Polyethylene Co., Ltd.) (hereinafter referred to as extruded resin 1) is extruded onto the treated surface in the form of a film with a thickness of 20 μm, which is then cooled by being clamped between a pair of cooling rolls (first extrusion process).

[0038] Corona discharge is applied to the uncoated surface of the base paper that has undergone the first extrusion process, and 20 μm of molten linear low-density polyethylene (Harmolex NH745N, manufactured by Japan Polyethylene Co., Ltd.) (hereinafter referred to as extrusion resin 2) and 20 μm of extrusion resin 1 are co-extruded onto the treated surface (second extrusion process). By going through the first and second extrusion processes, a sheet for body 11 with a layer structure of extrusion resin 1 (20 μm) / anchor coat / paper / extrusion resin 2 (20 μm) / extrusion resin 1 (20 μm) was created.

[0039] The sheet for the bottom 12 was also produced by the same process as described above. However, it is not necessary to use a sheet with the same layered structure as that of the body 11 for the sheet for the bottom 12, and a sheet with a different layered structure may be used.

[0040] The sheet for body 11 that had undergone the above-mentioned processes was punched out to a specified shape, the edges were treated by skiving and hemming, etc., and then it was rolled up into a rectangular tube with both ends partially overlapping each other (the grain of the paper runs vertically). The overlapping parts were then subjected to a heating treatment such as a frame treatment or hot air treatment to heat and melt the extruded resin 1 in the outermost and innermost layers of the overlapping parts, and the body 11 was formed by pressing it using a hot plate or the like.

[0041] The sheet for the bottom portion 12 was punched out to a predetermined shape, and the peripheral portion was bent to form the upright molded portion 12A.

[0042] The bottom 12 is inserted into the body 11 from the upper end opening of the body 11 with the upright molded portion 12A facing downward, the bottom 12 is fitted into the lower end opening of the body 11, and hot air is blown onto the lower end peripheral portion of the body 11 and the upright molded portion 12A of the bottom 12 to heat and melt the extruded resin 1. The lower end of the body 11 is folded inward to cover the upright molded portion 12A of the bottom 12, and the lower end (folded portion 11B) of the body 11 and the upright molded portion 12A of the bottom 12 are joined by knurling from the inside. The bottom of the paper cup body 10 is completed.

[0043] Finally, the upper end of the body 11 of the paper cup body 10 is curled outward using a curling die, and the curled portion is crushed from above and below to form the flange portion 11A. The paper cup body 10 is completed.

[0044] The completed paper cup body 10 had a capacity of 400 cc. No generation of roasted pinholes or the like was observed in the paper cup body 10. EXAMPLES

[0045] In the second extrusion process, a paper cup body 10 was produced in the same manner as in Example 1, except that the thickness of extruded resin 2 was 10 μm and the thickness of extruded resin 1 was 30 μm (layer structure: extruded resin 1 (20 μm) / anchor coat / paper / extruded resin 2 (10 μm) / extruded resin 1 (30 μm)). EXAMPLES

[0046] In the second extrusion process, a paper cup body 10 was produced in the same manner as in Example 1, except that the thickness of extruded resin 2 was 30 μm and that of extruded resin 1 was 10 μm (layer structure: extruded resin 1 (20 μm) / anchor coat / paper / extruded resin 2 (30 μm) / extruded resin 1 (10 μm)). EXAMPLES

[0047] In the second extrusion process, the uncoated surface of the base paper was subjected to anchor coat treatment in addition to corona discharge treatment, and a linear low-density polyethylene made by a different manufacturer (Yumerit 021GT, manufactured by Ube Maruzen Polyethylene Co., Ltd.) (hereinafter referred to as extruded resin 3) was laminated instead of extruded resin 2, in the same manner as in Example 1, except for this (layer structure: extruded resin 1 (20 μm) / anchor coat / paper / anchor coat / extruded resin 3 (20 μm) / extruded resin 1 (20 μm)). EXAMPLES

[0048] In the second extrusion process, the thickness of the extruded resin 3 was set to 10 μm, and the thickness of the extruded resin 1 laminated to the extruded resin 3 was set to 10 μm. The paper cup body 10 was produced in the same manner as in Example 4 (layer structure: extruded resin 1 (20 μm) / anchor coat / paper / anchor coat / extruded resin 3 (10 μm) / extruded resin 1 (30 μm)). Comparative Example 1

[0049] In the second extrusion process, the paper cup body 10 was produced in the same manner as in Example 1, except that the extruded resin 2 was not laminated, and only the extruded resin 1 was laminated to a thickness of 40 μm (layer structure of extruded resin 1 (20 μm) / anchor coat / paper / extruded resin 1 (40 μm)). Comparative Example 2

[0050] In the second extrusion process, the paper cup body 10 was produced in the same manner as in Example 1, except that the thickness of the extruded resin 2 was 5 μm and the thickness of the extruded resin 1 was 35 μm (layer structure: extruded resin 1 (20 μm) / anchor coat / paper / extruded resin 2 (5 μm) / extruded resin 1 (35 μm)). Comparative Example 3

[0051] In the second extrusion process, the paper cup body 10 was produced in the same manner as in Example 1, except that the thickness of the extruded resin 2 was 35 μm and the thickness of the extruded resin 1 was 5 μm (layer structure: extruded resin 1 (20 μm) / anchor coat / paper / extruded resin 2 (35 μm) / extruded resin 1 (5 μm)). Comparative Example 4

[0052] In the second extrusion process, a paper cup body 10 was produced in the same manner as in Example 1, except that only extruded resin 2 was extruded and its thickness was set to 40 μm (layer structure: extruded resin 1 (20 μm) / anchor coat / paper / extruded resin 2 (40 μm)).

[0053] For the lid material 20, a multi-layer sealant film was used, in which a base layer 20a was made of 12 μm thick PET (Ester Film E5200 manufactured by Toyobo Co., Ltd.), a printing layer (Gravure Ink Finart manufactured by DIC Graphics Inc.) and an adhesive (two-component curing urethane adhesive RU-77T / hardener H-7 manufactured by Rock Paint Co., Ltd.), and a surface resin layer 20b, an adhesive layer 20c, a peeling layer 20d and a sealing layer 20e were laminated in this order.

[0054] The base layer 20a was made by gravure printing ink on one side of a PET film, and dry laminating a separately prepared unprinted (non-printed) PET film onto the printed side of the gravure-printed PET film via a two-component curing urethane adhesive. The cover material 20 was made by dry laminating the surface resin layer 20b of the multilayer sealant film described above onto the non-printed PET film of the base layer 20a. In the base layer 20a, a vapor-deposited PET film may be used instead of the PET film, or an OPP (oriented polypropylene) film, an Ny (nylon) film, or an MDO-PE (uniaxially oriented polyethylene) film may be used. A barrier base material such as aluminum foil may also be used. The base layer 20a may be a single layer, or may be a multilayer combining one or more types of films.

[0055] The above-mentioned lid material 20 was placed on the upper surface of the flange portion 11A of the nine types of paper cup bodies 10 of Examples 1 to 5 and Comparative Examples 1 to 4 prepared as described above, and heat sealed (initial adhesion) under conditions of 150°C, 0.3 MPa, and 1 second, thereby producing nine types of paper cups with lids 1. As described above, in the lid material 20, the sealing layer 20e is used for this initial adhesion.

[0056] <Evaluation of paper cups with lids> For the 9 types of paper cup bodies 10 of the lidded paper cups 1 of Examples 1 to 5 and Comparative Examples 1 to 4 prepared as described above, (1) paper peeling evaluation, (2) sealing strength evaluation, (3) initial opening strength evaluation, and (4) opening strength evaluation after resealing were performed.

[0057] (1) Paper peeling evaluation The prepared paper cup with lid 1 was placed horizontally, the lid material 20 was peeled off from the corner of the paper cup with lid 1 (see Figure 1), and the degree of paper peeling was observed. Paper peeling refers to the paper cup with lid 1 being opened in a state where the paper layer 11a of the paper cup body 10 constituting the paper cup with lid 1 is cohesively peeled off and part of the paper layer 11a is attached to the lid material 20. The paper peeling evaluation was performed using the following four-level scale.

[0058] ++: No peeling of the paper occurred, and the lid material 20 was opened with the adhesive layer 20c exposed. +: No peeling of the paper occurred and the adhesive layer 20c was exposed in the opened lid material 20, but stretching of the linear low-density polyethylene layer 11c (extruded resin 2 or 3) of the paper cup body 10 was observed when the lid material 20 was opened. -: No peeling of the paper occurred, but when the lid material 20 was opened, the linear low-density polyethylene layer 11c (extruded resin 2 or 3) of the paper cup body 10 stretched, and part of it adhered to the lid material 20, and part of the adhesive layer 20c was not exposed. --: Paper peeling occurred, part of the paper layer 11a was attached to the lid material 20, and part of the adhesive layer 20c was not exposed.

[0059] (Test Results) In the paper cups 1 with lids using the paper cup bodies 10 of Examples 1, 2, 4, and 5, neither paper peeling nor stretching of the linear low-density polyethylene layer 11c occurred, and the adhesive layer 20c was well exposed in the lid material 20 (++). In the paper cups 1 with lids using the paper cup bodies 10 of Example 3, no paper peeling occurred, but stretching of the linear low-density polyethylene layer 11c occurred. However, the stretched linear low-density polyethylene layer 11c remained in the paper cup body 10 and did not adhere to the lid material 20, and the adhesive layer 20c was well exposed in the lid material 20 (+). In the paper cups 1 with lids using the paper cup bodies 10 of Comparative Examples 3 and 4, no paper peeling occurred, but stretching of the linear low-density polyethylene layer 11c occurred, and part of it adhered to the lid material 20 (-). In the paper cups 1 with lids using the paper cup bodies 10 of Comparative Examples 1 and 2, paper peeling occurred (--).

[0060] With reference to the paper peeling evaluation, instead of laminating a low-density polyethylene layer (extruded resin 1) to the paper layer 11a of the sheet constituting the paper cup body 10, a linear low-density polyethylene layer 11c (extruded resin 2 or 3) having a thickness of 10 to 30 μm was laminated to the paper layer 11a, and then a low-density polyethylene layer 11d (extruded resin 1) was laminated thereon, thereby preventing paper peeling (Examples 1 to 5).

[0061] In addition, comparing Examples 1, 2, 4, and 5 with Example 3, when the thickness of the linear low-density polyethylene layer 11c was increased (30 mm thick), paper peeling did not occur, but stretching of the linear low-density polyethylene layer 11c was observed (Example 3), and further referring to Comparative Examples 3 and 4, when the thickness of the linear low-density polyethylene layer 11c was further increased (35 mm for Comparative Example 3, 40 mm for Comparative Example 4), paper peeling did not occur, but the linear low-density polyethylene layer 11c further stretched, part of which adhered to the lid material 20, and the exposure of the adhesive layer 20c was prevented by the linear low-density polyethylene layer 11c. In addition, when the linear low-density polyethylene layer 11c was not laminated, or when it was laminated but the layer thickness was thin (5 mm thick), paper peeling occurred (Comparative Examples 1 and 2). In order to prevent the paper from peeling, it is effective to laminate a linear low-density polyethylene layer 11c having a specified layer thickness or more (10 mm or more), and it is found that in order to prevent the linear low-density polyethylene layer 11c from adhering to the lid material 20, the layer thickness of the laminated linear low-density polyethylene layer 11c must be set to a specified layer thickness or less (30 mm or less).

[0062] (2) Sealing strength evaluation The created paper cup with lid 1 was placed horizontally, an adhesive rubber plate was attached to the top surface of the lid material 20, an air needle was pierced into the lid material 20 through the adhesive rubber plate, and its tip was brought into the paper cup body 10, and air was sent into the paper cup body 10 through the air needle at a rate of 0.5 mL / min. The adhesive rubber plate can prevent air leakage from around the pierced air needle. Air was sent in until the paper cup body 10 burst, and the air pressure was measured when the paper cup body 10 burst.

[0063] (Test Results) Example 1: 16.0 kPa Example 2: 15.6 kPa Example 3: 16.5 kPa Example 4: 15.0 kPa Example 5: 14.8 kPa Comparative Example 1: 14.0 kPa Comparative Example 2: 14.5kPa Comparative Example 3: 16.5kPa Comparative Example 4: 16.7kPa

[0064] Regarding the sealing strength, when Examples 1 to 5 are compared with Comparative Example 1, it is confirmed that the lamination of the linear low-density polyethylene layer 11c contributes to improving the sealing strength.

[0065] (3) Initial opening strength evaluation The prepared paper cup with lid 1 was placed horizontally, two 15 mm wide cuts were made in the periphery of the lid material 20, and the 15 mm wide area of ​​the lid material 20 was turned up to separate the lid material 20 from the flange portion 11A of the paper cup body 10, and the maximum strength was measured. For the measurement of the initial opening strength, a Tensilon universal material testing machine manufactured by A&D Co., Ltd., equipped with a pair of grippers spaced apart in the vertical direction, was used. One (lower) gripper gripped the paper cup body 10 to fix the paper cup body 10, and the other (upper) gripper gripped the tip of the lid material 20 in the above-mentioned 15 mm wide area, and the other gripper was moved upward to pull the lid material 20 upward (at an angle of 90 degrees from the surface of the flange portion 11A of the paper cup body 10) until it was completely separated from the flange portion 11A. The speed at which the lid material 20 was turned up was 50 mm / min. Since the initial opening strength differs between the straight portion and the corner portion of the paper cup body 10, the initial opening strength was measured at two locations, the straight portion and the corner portion, for each of Examples 1 to 5 and Comparative Examples 1 to 4. In the straight portion, the above-mentioned cut was made at a right angle to the flange portion 14A in the linearly extending range. In the corner portion, the above-mentioned cut was made in the direction connecting a pair of diagonally opposite corner portions.

[0066] (Test Results) Example 1: Straight section 20.9N, corner section 15.6N Example 2: Straight section 21.2N, corner section 17.1N Example 3: Straight section 20.5N, corner section 14.8N Example 4: Straight section 20.4N, corner section 15.5N Example 5: Straight section 20.4N, corner section 16.3N Comparative Example 1: Straight section 21.3N, corner section 20.1N Comparative Example 2: Straight section 21.0 N, corner section 19.7 N Comparative Example 3: Straight section 20.8N, corner section 14.8N Comparative Example 4: Straight section 20.3 N, corner section 14.0 N

[0067] Regarding the initial opening strength, no significant difference was found between Examples 1-5 and Comparative Examples 1-4.

[0068] (4) Evaluation of strength after resealing (reopening strength) In the above-mentioned initial opening strength evaluation, the lid material 20 that had been opened was pressed by hand against the flange portion 11A to return it to its original state (resealing), and then a 15 mm wide area of ​​the lid material 20 was turned up again, and the maximum strength value was measured when the lid material 20 was separated from the flange portion 11A of the paper cup body 10. The speed at which the lid material 20 was turned up was 50 mm / min. For the evaluation of opening strength after resealing, values ​​were measured at two locations, the straight section and the corner section. The re-opening strength was also measured in the same manner using the same testing machine as that used to measure the above-mentioned initial opening strength.

[0069] (Test Results) Example 1: Straight section 2.4N, corner section 0.7N Example 2: Straight section 2.5N, corner section 0.8N Example 3: Straight section 2.2N, corner section 0.7N Example 4: Straight section 2.2N, corner section 0.7N Example 5: Straight section 2.2N, corner section 0.7N Comparative Example 1: Straight section 0N, corner section 0N Comparative Example 2: Straight section 0N, corner section 0N Comparative Example 3: Straight section 1.6N, corner section 0.3N Comparative Example 4: Straight section 1.3N, corner section 0.3N

[0070] In Comparative Examples 1 to 4, a decrease in strength was confirmed when the package was opened again because the paper layer 11a or the linear low-density polyethylene layer 11c prevented the adhesive layer 20c of the lid material 20 from being exposed. It was confirmed that the opening strength after resealing was greatly improved by laminating the linear low-density polyethylene layer 11c with an appropriate layer thickness (10 to 30 mm).

[0071] In Comparative Examples 1 to 4, when the lid material 20 is initially opened, it is found that the paper layer 11a or the linear low-density polyethylene layer 11c does not always stick to the lid material 20 over the entire circumference of the flange portion 11A, but the paper layer 11a or the linear low-density polyethylene layer 11c tends to stick to the lid material 20 in a part of the flange portion 11A. In the range where no paper peeling or no sticking of the linear low-density polyethylene layer 11c to the lid material 20 occurs, there is no or only a small decrease in the opening strength after resealing even in Comparative Examples 1 to 4. However, if the paper layer 11a or the linear low-density polyethylene layer 11c sticks to the lid material 20 even in a part, it becomes impossible to close the upper end opening of the paper cup body 10 in that range. To ensure resealability over the entire circumference of the flange portion 11A, it is appropriate to use the paper cup body 10 of Examples 1 to 5.

[0072] The above evaluation test results are summarized in the following Table 1. It was confirmed that in the initial state, the lidded paper cup 1 of this embodiment can keep the top opening of the paper cup body 10 tightly closed by the lid material 20, and that even when the lid material 20 is opened once and then the same lid material 20 is used to close the top opening again, the entire periphery of the top opening of the paper cup body 10 can be kept closed.

[0073] [Table 1] [Explanation of symbols]

[0074] 1 paper cup with lid 10 Paper cup body 11. Torso 11a Paper layer 11b, 11d Low density polyethylene layer 11c Linear low density polyethylene layer 11A Flange part 12 Bottom 20 Lid material 20a Base material layer 20b Surface resin layer 20c Adhesive layer (resealing layer) 20d peeling layer 20e Sealing layer

Claims

1. The paper cup body has a cylindrical body and a bottom that closes the lower end of the body, and a flange is formed at the upper end of the body by folding the upper end of the body outward; and a lid that is bonded to the upper surface of the flange and closes the upper end opening of the body, The body portion is composed of a low-density polyethylene layer, a linear low-density polyethylene layer, and a paper layer from its inner surface to its outer surface, The lid material includes a seal layer used for initial adhesion to the upper surface of the flange portion, and an adhesive layer laminated on the inner layer side of the seal layer and exposed to the outside when the lid material is peeled off from the upper surface of the flange portion. A paper cup with a resealable lid.

2. The linear low-density polyethylene layer has a thickness of 10 to 30 μm. The paper cup with a lid having a resealing function according to claim 1.

3. A release layer is laminated between the seal layer and the adhesive layer of the lid material. The paper cup with a lid having a resealing function according to claim 1.

4. A low-density polyethylene layer is laminated on the outer surface of the paper layer of the body. The paper cup with a lid having a resealing function according to claim 1.

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