Heat-insulating paper container

Abstract

To provide a heat-insulating paper container capable of preventing defective reading of a JAN code by reducing manufacturing man-hours and improving handleability from production to using.SOLUTION: In a heat-insulating paper container 1 comprising a cylindrical trunk member 2 and a bottom member 3 closing a bottom surface of the trunk member 2, the trunk member 2 includes at least a paper layer 24, an inner surface resin layer 21 arranged on an inner surface side of the paper layer 24, and a foam ink layer 27 in which foam ink foaming at predetermined temperature is arranged on an outer surface side of the paper layer 24 in an unfoamed state.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a heat-insulating paper container having a body member and a bottom member. [Background technology]

[0002] A conventional heat-insulating paper container used for coffee, instant noodles, etc. is disclosed in Patent Document 1. This heat-insulating paper container is formed in a cup shape with a cylindrical body member and a bottom member that closes the bottom surface of the body member. The body member has thermoplastic resin layers laminated on both sides of a paper layer, and a printed layer provided on the outer peripheral surface. The thermoplastic resin layer on the outer peripheral side of the paper layer is foamed by heating. This gives the body member heat insulation, making the heat-insulating paper container filled with coffee, etc., easy to hold in the hand.

[0003] Also known is a heat-insulating container in which a printed layer made of foaming ink is provided and the surface of the printed layer is foamed by heating. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3414978 (pages 4 to 6, Figure 1) [Patent Document 2] Patent No. 3408156 (pages 7 to 12, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional heat-insulating paper containers generally require a foaming step in a high-temperature foaming oven during production, which increases the number of manufacturing steps, and also increases the amount of carbon dioxide emissions due to the use of the foaming oven.

[0006] In addition, with the former heat-insulating paper container, foaming of the thermoplastic resin layer directly below the printed layer is suppressed more than foaming of the thermoplastic resin layer not coated with the printed layer. This causes the outer peripheral surface to become uneven and the smoothness to decrease, and the print applied to the outer peripheral surface becomes deformed, distorted, blurred, etc., impairing the appearance and reducing visibility. In addition, the deformation of the JAN code formed by the printed layer may cause frequent reading errors by the barcode reader.

[0007] In the latter case, the surface of the foamed ink has small irregularities that make it difficult to slip after foaming. Therefore, when the cup-shaped heat-insulating paper containers are stacked, it is difficult to take out each one, and the heat-insulating paper containers are difficult to handle.

[0008] The present invention aims to provide a heat-insulating paper container that can reduce manufacturing steps, improve handleability from production to use, and prevent JAN code reading errors. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the present invention provides an insulating paper container comprising a cylindrical body member and a bottom member that covers the bottom surface of the body member, the body member having at least a paper layer, an inner surface resin layer made of a thermoplastic resin arranged on the inner surface side of the paper layer, and a foaming ink layer in which a foaming ink that foams at a predetermined temperature is arranged in an unfoamed state on the outer surface side of the paper layer.

[0010] Further, the present invention is characterized in that in the heat-insulating paper container having the above-mentioned configuration, the foaming ink foams at 60 to 125°C.

[0011] Furthermore, the present invention is characterized in that in the heat-insulating paper container having the above-mentioned configuration, the foaming ink contains thermally expandable microcapsules, and the average particle size of the microcapsules when not foamed is 5 to 25 μm.

[0012] Furthermore, the present invention is characterized in that in the heat-insulating paper container having the above-mentioned configuration, the foamed ink layer is provided in a band shape extending in the circumferential direction on the outer circumferential surface of the body member.

[0013] Further, the present invention provides a heat-insulating paper container having the above-mentioned configuration, wherein the body member has a top curl portion in which an upper end is curled outward and a bottom folded portion in which a lower end is folded inward, The foamed ink layer is provided on the entire outer peripheral surface of the body member excluding the top curl portion and the bottom folded portion.

[0014] Furthermore, the present invention is characterized in that in the heat insulating paper container having the above-mentioned configuration, an intermediate layer formed of a resin film is provided between the first thermoplastic resin layer and the paper layer.

[0015] Furthermore, the present invention is characterized in that in the heat-insulating paper container having the above-mentioned structure, the intermediate layer has an oxide vapor deposition film or a metal vapor deposition film.

[0016] The present invention is also characterized in that in the heat-insulating paper container having the above-mentioned structure, an outer resin layer made of a thermoplastic resin is provided between the paper layer and the foamed ink layer. Effect of the Invention

[0017] According to the present invention, since the foamed ink layer is in an unfoamed state, the foaming step is not necessary, and the manufacturing man-hours of the heat-insulating paper container can be reduced. In addition, since no unevenness is formed on the surface, the individual heat-insulating paper containers can be easily removed when stacked. This improves the handleability of the heat-insulating paper container from production to use, and prevents JAN code reading errors. In addition, the foamed ink layer foams when the consumer uses it by pouring hot water or the like. This gives a change to the appearance of the heat-insulating paper container, improving its design, and since the foamed ink layer has poor slipperiness after foaming, the heat-insulating paper container can be easily gripped. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing a heat-insulating paper container according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a front cross-sectional view showing a heat-insulating paper container according to a first embodiment of the present invention. [Diagram 3] FIG. 1 is an enlarged cross-sectional view showing a laminated structure of a body member of a heat-insulating paper container according to a first embodiment of the present invention. [Figure 4] FIG. 1 is an enlarged cross-sectional view showing a foamed ink layer of a body member of a heat-insulating paper container according to a first embodiment of the present invention during foaming. [Diagram 5] FIG. 11 is an enlarged cross-sectional view showing the laminated structure of the body member of the heat-insulating paper container according to the second embodiment of the present invention. [Figure 6] FIG. 11 is an enlarged cross-sectional view showing the laminated structure of the body member of the heat-insulating paper container according to the third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figures 1 and 2 show a perspective view and a front cross-sectional view of a heat-insulating paper container of the first embodiment. The heat-insulating paper container 1 is formed in a cup shape and is used for hot drinks such as coffee, black tea, and green tea, and for instant foods such as ramen, soup, and miso soup.

[0020] The heat-insulating paper container 1 comprises a body member 2 made of a cylindrical laminate, and a bottom member 3 made of a laminate joined to the body member 2. The upper end of the body member 2 is provided with a top curl portion 2a where the laminate is curled outward. The lower end of the body member 2 is provided with a bottom folded portion 2b where the laminate is folded inward. The periphery of the bottom member 3 is provided with a bent portion 3a bent outward. The body member 2 and the bottom member 3 are joined by engaging the folded portion 2b with the bent portion 3a. A band-shaped heat-insulating portion 2c extending in the circumferential direction is formed on the outer peripheral surface of the body member 2 by a foamed ink layer 27 (see Figure 3), the details of which will be described later, avoiding the top curl portion 2a and the bottom folded portion 2b.

[0021] 3 is an enlarged cross-sectional view showing the layered structure of body member 2. Body member 2 is formed from a laminate in which, from the inner surface side, inner surface resin layer 21, paper layer 24, and outer surface resin layer 25 are laminated. A printing layer 26 on which designs such as letters, figures, etc. are printed is provided on outer surface resin layer 25. A foamed ink layer 27 printed with foamed ink is provided on printing layer 26. The designs such as letters, figures, etc. may be formed by foamed ink layer 27, or may be formed by both printing layer 26 and foamed ink layer 27.

[0022] The paper layer 24 has a basis weight of 200 g / cm 2 ~300g / cm 2 The paper layer 24 is made of paper such as a cup base paper having a thickness of about 150 μm to 300 μm.

[0023] The inner surface resin layer 21 is laminated on one surface of the paper layer 24 by extrusion coating, lamination, or the like. The inner surface resin layer 21 is formed of a thermoplastic resin such as polyethylene resin, and prevents the liquid contents from penetrating into the paper layer 24. The thickness of the inner surface resin layer 21 is about 20 μm to 80 μm.

[0024] The outer resin layer 25 is laminated on the other side of the paper layer 24 by extrusion coating, lamination, or the like. The outer resin layer 25 is formed from a thermoplastic resin such as polyethylene resin. The thickness of the outer resin layer 25 is about 10 μm to 40 μm. It is more preferable to form the inner resin layer 21 and the outer resin layer 25 from a low-density polyethylene resin because this has good processability.

[0025] The outer resin layer 25 may be made of polyethylene having a lower density than the inner resin layer 21. This allows the outer resin layer 25 to foam and maintain the heat insulating properties of the insulated paper container 1 even if the microcapsules in the foaming ink described below are broken during high-temperature processing.

[0026] Also, the outer resin layer 25 may be omitted, and the printed layer 26 and the foamed ink layer 27 may be provided on the paper layer 24. This reduces the amount of resin used, and reduces the amount of carbon dioxide emissions during production and the production costs.

[0027] The printed layer 26 is formed by gravure printing with an ink containing a resin component in a solvent, or an ink further containing a pigment or coloring dye if colored. Examples of the resin component contained in the ink include urethane resin, butyral resin, copolymer of alkyd and nitrocellulose, polyamide, acrylic, copolymer of acrylic and rosin, and chlorinated polyolefin. The thickness of the printed layer 26 is about 2 to 3 μm.

[0028] The foamed ink layer 27 is gravure printed on the printed layer 26 with a foaming ink that foams at a predetermined foaming temperature, and is disposed in an unfoamed state. The foamed ink layer 27 has a thickness of about 1 to 10 μm. The foamed ink layer 27 is formed continuously with the same printing device as the printed layer 26. Therefore, the provision of the foamed ink layer 27 does not increase the number of manufacturing steps.

[0029] Foaming ink is a mixture of thermally expandable microcapsules in an organic solvent solution or aqueous emulsion using a thermoplastic resin such as a urethane resin as a binder. The microcapsules are made of a thermoplastic resin with low gas permeability such as vinylidene chloride-acrylonitrile copolymer, and contain a low-boiling liquid expansion agent such as propane, butane, isobutane, or pentane. As a result, the foaming ink expands at a predetermined foaming temperature by the expansion of the microcapsules, for example, at a magnification of 4 to 10 times.

[0030] At this time, a low boiling point liquid expansion agent is selected so that the microcapsules expand at a desired temperature within a range of 60 to 125°C. This allows the unfoamed foamed ink layer 27 to heat up and foam when a hot drink, boiling water, or the like is poured into the heat-insulating paper container 1, or when cooking is performed in a microwave oven or the like after pouring water. Alternatively, a low boiling point liquid expansion agent may be selected so that the microcapsules expand at a desired temperature within a range of 60 to 100°C. This allows the foamed ink layer 27 to foam when a hot drink, boiling water, or the like is poured into the heat-insulating paper container 1.

[0031] Moreover, the average particle diameter of the unfoamed microcapsules is preferably 5 to 25 μm. If the average particle diameter of the unfoamed microcapsules is smaller than 5 μm, they will aggregate and the foaming of the foamed ink layer 27 will become non-uniform. If the average particle diameter of the unfoamed microcapsules is larger than 25 μm, there are cases where the microcapsules cannot be applied uniformly during gravure printing.

[0032] Moreover, the average particle size of the microcapsules after foaming is preferably 30 to 120 μm. If the average particle size of the microcapsules after foaming is less than 30 μm, the heat insulating effect may be poor. If the average particle size of the microcapsules after foaming is greater than 120 μm, it becomes difficult to hold the microcapsules with the binder that becomes the ink solid content, and the microcapsules may fall off after foaming.

[0033] As an example of the water-based foamed ink, a foamed ink having the following components can be used.

[0034] Ethylene vinyl acetate copolymer emulsion: 73.0% by weight Microspheres (volatile liquid-encapsulated microcapsules): 20.0% by weight Antifoaming agent: 0.5% by weight Ethylene glycol: 5.0% by weight Hydroxyethyl cellulose (thickener): 1.5% by weight

[0035] As an example of an oil-based type foamed ink, a foamed ink having the following components can be used.

[0036] Acrylic resin: 75.0% by weight Toluene: 8.9% by weight Microspheres (volatile liquid-encapsulated microcapsules): 15.0% by weight Antifoaming agent: 0.1% by weight Silica (thickener): 1.0% by weight

[0037] 2, the bottom member 3 is formed of a laminate of a paper layer and an inner resin layer disposed inside the paper layer. The paper layer of the bottom member 3 has a basis weight of 200 g / cm, similar to the paper layer of the body member 2. 2 ~300g / cm 2 The bottom member 3 is made of paper such as a cup base paper having a thickness of about 150 μm to 300 μm.

[0038] The inner resin layer of the bottom member 3 is laminated on one side of the paper layer by extrusion coating, lamination, or the like. The inner resin layer of the bottom member 3 is formed of a thermoplastic resin such as polyethylene resin. It is more preferable to form the inner resin layer of the bottom member 3 from low-density polyethylene resin, as this has good processability. The thickness of the inner resin layer of the bottom member 3 is about 20 to 60 μm.

[0039] When a hot drink or boiling water is poured into the insulating paper container 1 having the above configuration, the foamed ink layer 27 changes from an unfoamed state to a foamed state and increases in volume, as shown in Figure 4. At this time, the surface of the foamed ink layer 27 becomes uneven, so that the insulating portion 2c (see Figure 1) has an insulating effect, and the insulating paper container 1 can be held on the insulating portion 2c with fingers.

[0040] In addition, the surface of the foamed ink layer 27 changes from a smooth surface to a matte surface due to the unevenness, which changes the aesthetic appearance of the heat-insulating paper container 1 and improves the design, while also improving the grip.

[0041] In addition, the surface of the foamed ink layer 27 is smooth because it is in an unfoamed state before the hot drink or boiling water is poured in. This makes the foamed ink layer 27 slippery, and when the cup-shaped insulating paper containers 1 are stacked, each one can be easily removed, improving the handleability of the insulating paper container 1.

[0042] Furthermore, when a transparent foamed ink layer 27 is provided on the JAN code formed by the printing layer 26, it is possible to prevent errors in reading the JAN code because the surface of the foamed ink layer 27 is smooth. Similarly, when the JAN code is formed by the foamed ink layer 27, it is possible to prevent errors in reading the JAN code because the surface of the foamed ink layer 27 is smooth.

[0043] According to this embodiment, since the foamed ink layer 27 is in an unfoamed state, a foaming process is not necessary, and the number of steps required to manufacture the insulating paper container 1 can be reduced. In addition, since no irregularities are formed on the surface, the individual insulating paper containers 1 can be easily removed when stacked. This improves the ease of handling of the insulating paper container 1 from production to use, and prevents problems with reading the JAN code.

[0044] Furthermore, when a consumer uses the container, the foaming ink layer 27 foams by pouring hot water or the like. This allows the appearance of the heat-insulating paper container 1 to be changed to improve its design, and the foaming ink layer 27 has poor slipperiness after foaming, improving the grip of the heat-insulating paper container 1.

[0045] Moreover, since the foaming ink foams at 60 to 125° C., the foaming ink layer 27 can be foamed reliably when a hot drink or boiling water is poured into it, or when heated in a microwave oven after pouring water into it.

[0046] In addition, because the average particle diameter of the microcapsules contained in the foamed ink is 5 μm or more, aggregation can be prevented, improving printability and enabling uniform printing of the foamed ink layer 27. This allows for uniform foaming of the foamed ink layer 27. In addition, because the average particle diameter of the microcapsules is 25 μm or less, the ink transfer during printing is good, making it suitable for gravure printing.

[0047] In addition, since the foamed ink layer 27 is provided in a band shape extending in the circumferential direction on the outer circumferential surface of the body member 2, the heat-insulating paper container 1 can be easily held on the heat-insulating portion 2c consisting of the foamed ink layer 27.

[0048] In addition, an outer resin layer 25 made of a thermoplastic resin is provided between the paper layer 24 and the foamed ink layer 27.

[0049] <Second embodiment> Next, Fig. 5 is an enlarged cross-sectional view showing the body member 2 of a heat-insulating paper container 1 of a second embodiment. In this embodiment, a foamed ink layer 27 is provided on the outer surface of an outer resin layer 25, and a printed layer 26 is provided on the foamed ink layer 27. The other parts are the same as those of the first embodiment shown in Figs. 1 to 4 described above.

[0050] According to this embodiment, it is possible to obtain the same effect as in the first embodiment. Furthermore, when a transparent printed layer 26 is provided on the JAN code formed by the foamed ink layer 27, the surface of the foamed ink layer 27 is smooth, so that it is possible to prevent errors in reading the JAN code. Similarly, when a JAN code is formed on the foamed ink layer 27 by the printed layer 26, the surface of the foamed ink layer 27 is smooth, so that it is possible to prevent errors in reading the JAN code.

[0051] <Third embodiment> Next, Fig. 6 is an enlarged cross-sectional view showing the body member 2 of a heat-insulating paper container 1 of a third embodiment. In this embodiment, an intermediate layer 23 is provided between an inner resin layer 21 and a paper layer 24. Other parts are similar to those of the first embodiment shown in Figs. 1 to 4 described above.

[0052] The intermediate layer 23 has a vapor-deposited film 23b on a base film 23a, and is laminated on the paper layer 24 by a dry lamination method. The base film 23a is made of nylon, polyethylene terephthalate, or the like, and has a thickness of about 5 to 30 μm. The vapor-deposited film 23b is made of an oxide vapor-deposited film (aluminum oxide, silicon oxide, etc.) or a metal vapor-deposited film (aluminum, etc.). This gives the intermediate layer 23 barrier properties. Therefore, the top surface of the heat-insulating paper container 1 can be sealed to preserve instant foods for long periods of time.

[0053] According to this embodiment, it is possible to obtain the same effects as those of the first embodiment. In addition, since the intermediate layer 23 having a barrier property is provided between the inner resin layer 21 and the paper layer 24, the instant food can be preserved for a long period of time.

[0054] Furthermore, since the intermediate layer 23 has an oxide vapor deposition film or a metal vapor deposition film, the barrier properties of the heat-insulating paper container 1 can be easily achieved.

[0055] In this embodiment, since the base film 23a made of nylon, polyethylene terephthalate or the like has a barrier property, the vapor deposition film 23b may be omitted to form the intermediate layer 23. Also, a foamed ink layer 27 may be provided on the outer surface of the outer resin layer 25, and a printed layer 26 may be provided on the foamed ink layer 27, as in the second embodiment.

[0056] In the first to third embodiments, the foamed ink layer 27 is provided in a band shape extending in the circumferential direction of the body member 2, but the foamed ink layer 27 may be formed in any shape. The foamed ink layer 27 may also be provided on the entire outer peripheral surface of the body member 2 except for the top curl portion 2a and the bottom folded portion 2b. This allows the body member 2 to be held anywhere, improving the usability of the heat-insulating paper container 1. [Industrial Applicability]

[0057] INDUSTRIAL APPLICABILITY The present invention can be used for heat-insulating paper containers for hot drinks, instant foods, and the like. [Explanation of symbols]

[0058] 1. Insulated paper containers 2 Body parts 2a Top curl section 2b Bottom folded part 2c Insulation section 3 Bottom member 3a Bend part 21 Inner resin layer 23 Middle Class 23a Base film 23b Evaporation film 24 paper layer 25 Outer resin layer 26 Printing layer 27 Foamed ink layer

Claims

1. An insulating paper container comprising a cylindrical body member and a bottom member that covers the bottom surface of the body member, characterized in that the body member has at least a paper layer, an inner resin layer made of a thermoplastic resin arranged on the inner surface side of the paper layer, and a foaming ink layer in which a foaming ink that foams at a predetermined temperature is arranged in an unfoamed state on the outer surface side of the paper layer.

2. 2. The heat-insulating paper container according to claim 1, wherein the foaming ink foams at a temperature of 60 to 125°C.

3. 3. The heat-insulating paper container according to claim 1, wherein the foaming ink contains thermally expandable microcapsules, and the average particle size of the microcapsules when unfoamed is 5 to 25 μm.

4. 3. The heat-insulating paper container according to claim 1, wherein the foamed ink layer is provided in a band shape extending in a circumferential direction on the outer circumferential surface of the body member.

5. The body member has a top curl portion having an upper end curled outward and a bottom folded portion having a lower end folded inward, 3. The heat-insulating paper container according to claim 1, wherein the foamed ink layer is provided on the entire outer peripheral surface of the body member excluding the top curl portion and the bottom folded portion.

6. 3. The heat-insulating paper container according to claim 1, further comprising an intermediate layer having a barrier property provided between the inner resin layer and the paper layer.

7. The heat-insulating paper container according to claim 6, characterized in that the intermediate layer has an oxide vapor deposition film or a metal vapor deposition film.

8. 3. The heat-insulating paper container according to claim 1, further comprising an outer resin layer made of a thermoplastic resin provided between said paper layer and said foamed ink layer.

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