Packaging materials and press-through packages

Abstract

To realize a packaging material that does not contain nitrocellulose resin but is excellent in adhesiveness and heat resistance, and a press-through package comprising the same.SOLUTION: A packaging material 30 comprises an aluminum foil 33 and a coat layer 35 provided on a one-surface side of the aluminum foil. The coat layer 35 consists of curable resin containing cellulosic resin and acryl resin without containing nitrocellulose resin and melamine resin.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present technology relates to packaging materials and press-through packages.

Background Art

[0002] Conventionally, a press-through package (PTP) is known as a packaging container for accommodating tablets and the like, and an example thereof is disclosed in Patent Document 1. The PTP described in Patent Document 1 includes a sheet-like resin container including a housing portion in which an object to be housed is housed, and a lid material heat-bonded to the resin container so as to cover an opening of the housing portion. Further, the PTP uses an aluminum laminate for the lid material, so that excellent moisture-proof property is realized, and the lid material can be easily opened by breaking it with an appropriate pressing force at the time of opening.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in recent years, there has been a demand for realizing a so-called nitrocellulose-free product that does not contain nitrocellulose resin in PTP due to the influence on the human body (health concerns). Nitrocellulose resin is excellent in adhesion and heat resistance, and has been widely used for the coating layer disposed on the outermost layer of the lid material of conventional PTP, but alternative materials are required. The coating layer protects the lid material from high temperatures when the lid material is heat-bonded to the sheet-like container during the manufacture of PTP, and protects the lid material from damage caused by external forces during transportation. Therefore, the coating layer is preferably formed of a material having heat resistance and adhesion (adhesive strength) that is not easily peeled off by external forces.

[0005] This technology was developed based on the circumstances described above, and aims to realize a packaging material that does not contain nitrocellulose resin and has excellent adhesion and heat resistance, as well as a press-through package equipped with said packaging material. [Means for solving the problem]

[0006] The packaging material relating to the technology described in this specification comprises aluminum foil and a coating layer provided on one side of the aluminum foil, wherein the coating layer is made of a curable resin containing cellulose resin and acrylic resin, but not containing nitrocellulose resin and melamine resin.

[0007] Furthermore, in the packaging material having the above configuration, the mixing ratio of the cellulose resin and the acrylic resin in the curable resin is 40% to 75% for the cellulose resin and 25% to 60% for the acrylic resin, and the molecular weight of the cellulose resin may be 25,000 or more.

[0008] Furthermore, the packaging material having the above configuration may include a heat-sealable layer provided on the other side of the aluminum foil.

[0009] Furthermore, the packaging material having the above configuration includes an intermediate layer visible from the outside between the aluminum foil and the coating layer, and between the aluminum foil and the heat-bonding layer, and the intermediate layer may not contain nitrocellulose resin.

[0010] Furthermore, the packaging material having the above configuration may have an aluminum foil thickness of 6 μm or more and 35 μm or less.

[0011] The press-through package relating to the technology described in this specification comprises a sheet-like container including a storage section in which the contents to be contained are stored, and a packaging material attached to the sheet-like container so as to cover the opening of the storage section.

[0012] Furthermore, in the press-through package with the above configuration, the contents may be pharmaceuticals or food products. [Effects of the Invention]

[0013] This technology makes it possible to realize a packaging material that does not contain nitrocellulose resin and has excellent adhesion and heat resistance, as well as a press-through package equipped with this packaging material. [Brief explanation of the drawing]

[0014] [Figure 1] A cross-sectional view showing how the lid material is heat-bonded to the sheet-like container by a heat roll in the PTP according to Embodiment 1. [Figure 2] Enlarged cross-sectional view of the lid material in Figure 1. [Figure 3] Table showing the results of evaluation experiment 1 [Figure 4] Enlarged cross-sectional view of a lid material according to another embodiment. [Modes for carrying out the invention]

[0015] <Embodiment 1> Embodiment 1 will be described with reference to Figures 1 to 3. In this embodiment, a lid material 30 (an example of packaging material) and a press-through package (PTP) 10 to which the lid material 30 is attached are illustrated. Note that some of the drawings show the X, Y, and Z axes, and each axis is drawn in a direction common to all figures.

[0016] As shown in Figure 1, the PTP10 comprises a sheet-like container 20 including a storage section 21 in which the contents T (such as tablets containing pharmaceuticals) are stored, and a lid material 30 that is attached to the sheet-like container 20. The lid material 30 is heat-bonded to the sheet-like container 20 by a heat roll HR. The lid material 30, when heat-bonded (attached) to the sheet-like container 20, covers the opening 21A of the storage section 21 and seals the storage section 21. The planar shape and planar size of the lid material 30 are formed so as to be able to cover the entire side of one side of the sheet-like container 20, and in this embodiment, it is substantially identical to the sheet-like container 20.

[0017] The sheet-like container 20 includes a plurality of accommodating portions 21 that project on the side opposite to the lid member 30. The accommodating portion 21 has an internal space for accommodating the object to be accommodated T therein, and the boundary portion with the lid member 30 is an opening 21A. The accommodating portion 21 is formed in a shape following the shape of the object to be accommodated T when viewed in plan.

[0018] As the sheet-like container 20, a known one as a PTP sheet-like container is appropriately used. The sheet-like container 20 is, for example, a resin container in which a resin sheet material having a thickness of about 60 μm to 400 μm is subjected to a bulging process. The sheet-like container 20 is made of, for example, a transparent thermoplastic resin such as polyvinyl chloride, polyvinylidene chloride, polypropylene, amorphous polyethylene terephthalate, and does not contain nitrocellulose resin, which has been pointed out to have health concerns in recent years.

[0019] There is a concern in the pharmaceutical field that nitrocellulose resin reacts with dimethylamine remaining in the pharmaceutical product, which is the object to be accommodated T, to generate N-nitrosodimethylamine (NDMA), which is a carcinogenic substance. For this reason, in the applications of pharmaceuticals and foods, it is preferable that all the members constituting the PTP10 do not contain nitrocellulose resin, that is, it is so-called nitrocellulose-free.

[0020] The lid member 30 is a thin aluminum laminate that can be press-through. Of the lid member 30, except for the portion covering the opening 21A of the accommodating portion 21, it is thermally adhered to the sheet-like container 20. As shown in FIG. 2, the lid member 30 is an aluminum laminate in which a thermal adhesive layer 31, a first printing layer 32 (an example of an intermediate layer), an aluminum foil 33 (an example of a base material layer), a second printing layer 34 (an example of an intermediate layer), and a coat layer 35 are laminated in order from the lower side (the side of the sheet-like container 20).

[0021] The heat - adhesive layer 31 adheres to the sheet - like container 20 and covers the accommodating portion 21. The sealing property of the accommodating portion 21 is appropriately designed according to the use of the PTP10. It does not necessarily need to be airtight to the extent that no gas leaks, but it should be airtight to the extent that at least no solid leaks. A known heat - adhesive for PTP can be used for the heat - adhesive layer 31. For example, the heat - adhesive layer 31 is composed of a heat - adhesive such as a polyester - based adhesive, a polypropylene - based adhesive, a vinyl chloride - based adhesive, a vinyl chloride - vinyl acetate copolymer - based adhesive (vinyl chloride - vinyl acetate - based adhesive), etc., and does not contain nitrocellulose resin.

[0022] The temperature T1 at which the heat - adhesive layer 31 is heat - adhered, that is, the heating temperature T1 by the heat roll HR, is appropriately selected according to the use of the PTP10, but generally it is within the range of 200 °C to 300 °C. In recent years, the demand for low - temperature heat - adhesion that does not generate formaldehyde harmful to the human body during heat - adhesion is also large. In that case, the heating temperature T1 is about 210 °C to 220 °C.

[0023] The aluminum foil 33 is the base material layer of the lid material 30, and can particularly enhance the moisture - proof property compared with resin and paper. The foil thickness of the aluminum foil 33 is preferably 6 μm or more and 35 μm or less. When used as a single layer as in this embodiment, the foil thickness is more preferably 15 μm or more and 35 μm or less.

[0024] When the foil thickness of the aluminum foil 33 is less than 15 μm, the occurrence frequency of pinholes increases. Furthermore, when the foil thickness is less than 6 μm, the occurrence frequency of pinholes becomes extremely high, and the formability and handling property of the aluminum foil also deteriorate. On the other hand, when the foil thickness of the aluminum foil 33 exceeds 35 μm, the pressing force required for opening increases, and good opening property cannot be ensured. The lid material 30 is required to be difficult to be damaged during manufacturing or transportation and to be easily broken with an appropriate pressing force during opening.

[0025] As shown in Figure 2, the first printed layer 32 and the second printed layer 34 are provided on both main surfaces 33A1 and 33B1 of the aluminum foil 33, respectively. The first printed layer 32 and the second printed layer 34 are provided to display information about the contents T, and are formed on each main surface 33A1 and 33B1 of the aluminum foil 33 using a known printing method with colored printing ink. Each printed layer 32 and 34 is formed by printing a printing ink containing a coloring agent (pigment) such as carbon black, phthalocrinic blue, phthalocrinic green, quinacridone-based, azo-based, or titania in a binder resin using a gravure printing method. Each printed layer 32 and 34 is thus printed with colored ink so that it is visible from the outside, but the coating layer 35, heat-bonding layer 31, and sheet-like container 20 interposed between each printed layer 32 and 34 and the outside are made of a light-transmitting transparent or translucent material so that the printed layers 32 and 34 are visible from the outside.

[0026] In Figure 2, the two printed layers 32 and 34 are partially formed on the respective main surfaces 33A1 and 33B1 of the aluminum foil 33, but they may also be formed over the entire surface of the main surfaces 33A1 and 33B1. Furthermore, only one of the two printed layers 32 and 34 may be formed, and in cases where it is not necessary to display information about the contents T, neither layer may be formed.

[0027] As shown in Figure 2, the coating layer 35 is provided on one main surface 33A1 side of the aluminum foil 33 (the main surface 33A1 side opposite to the heat-bonding layer 31). The coating layer 35 is formed on the entire surface as the outermost layer of the lid material 30, covering and protecting the other layers of the lid material 30. For example, the coating layer 35 protects the lid material 30 from heating by the heat roll HR during manufacturing and from damage caused by external forces during transportation. Therefore, it is preferable that the coating layer 35 has heat resistance to heating by the heat roll HR and adhesion strength (adhesion) that prevents it from being easily peeled off by external forces.

[0028] The coating layer 35 is a thermosetting resin layer containing cellulose resin and acrylic resin, but not containing nitrocellulose resin or melamine resin. The thermosetting temperature T2 of the coating layer 35 is lower than the heating temperature T1 by the heat roll HR described above. Conventionally, nitrocellulose resin and melamine resin, which have excellent heat resistance and adhesion, have been widely used as materials for the coating layer 35. However, in recent years, as described above, there has been a demand for materials that do not contain nitrocellulose resin. Furthermore, it is preferable to omit melamine resin because residual formaldehyde in the manufacturing process can cause sick building syndrome, etc. The coating layer 35 according to this embodiment is formed by thermosetting a mixed resin material of cellulose resin, which has excellent heat resistance, and acrylic resin, which has excellent adhesion. This makes it possible to realize a lid material 30, and by extension the PTP 10, that does not contain nitrocellulose resin and has excellent adhesion and heat resistance.

[0029] Furthermore, as shown in the results of Evaluation Experiment 1 described later, the mixing ratio of cellulose resin and acrylic resin in the coating layer 35 is preferably 40% to 75% for cellulose resin and 25% to 60% for acrylic resin. Also, the molecular weight of the cellulose resin is preferably 25,000 or higher. Evaluation Experiment 1 will now be described in detail.

[0030] <Evaluation Experiment 1> In Evaluation Experiment 1, a simple sample was formed to evaluate the coating layer 35, and its adhesion and heat resistance were assessed. The results of the evaluation experiment are shown in the table in Figure 3.

[0031] <Evaluation Sample> A mixture of cellulose resin and acrylic resin is applied to one side (the glossy side) of a 20μm thick aluminum foil 33 at a rate of 1.5±0.2g / m². 2The material was applied and then heat-cured by heating at 180°C for 10 seconds. This resulted in a laminate with a coating layer 35 laminated on aluminum foil 33, which was used as an evaluation sample. Multiple evaluation samples were prepared with different mixing ratios of cellulose resin and acrylic resin, and different molecular weights of the cellulose resin, and these were designated as Examples 1 to 4 and Comparative Examples 1 to 2.

[0032] <Evaluation Method> In the adhesion test, adhesive tape (manufactured by Nichiban Co., Ltd., model number CT405AP-15) was attached to the surface of the coating layer 35 of the evaluation sample (the side opposite to the aluminum foil), and the peelability of the coating layer when the adhesive tape was removed was evaluated. The adhesion test was evaluated on a two-level scale of A or C, with A (good) indicating no peeling of the coating layer and C (poor) indicating some peeling.

[0033] In the heat resistance test, two of each evaluation sample were stacked so that the surfaces of the coating layer 35 were in contact with each other, and a flat plate heater was applied to them for 1 second. The pressure of the plate heater was 1 kgf / cm². 2 The heating temperature T1 was set to 180°C, 200°C, 220°C, 230°C, and 240°C. After heating, each evaluation sample, which was stacked in pairs, was evaluated to see if it could be peeled off one by one. The heat resistance test was evaluated on a three-level scale: A, B, and C. If the samples could be peeled off one by one without any resistance, it was rated A (Good) because the coating layer 35 had not melted at all. If the samples could be peeled off one by one, but there was slight resistance (catching) when peeling, it was rated B (Acceptable) because the coating layer 35 had melted slightly. On the other hand, if the samples could not be peeled off one by one, it was rated C (Unacceptable) because the coating layers 35 had adhered to each other and the coating layer 35 had completely melted.

[0034] The overall evaluation based on the adhesion and heat resistance tests described above was given in two stages: A or C. If the adhesion evaluation result was C (unacceptable), or if the heat resistance evaluation result from 180°C to 220°C was C (unacceptable), the product was classified as C (unacceptable) as it did not meet the standards. In all other cases, the product was classified as A (good) as it met the standards.

[0035] <Evaluation Results> The results of Evaluation Experiment 1 will be explained with reference to Figure 3. Adhesion was good in Examples 1 to 4 and Comparative Example 2, where the proportion of acrylic resin was 25% or more, but it was inferior in Comparative Example 1, where the proportion was 15%.

[0036] The heat resistance was better in the examples and comparative examples with a higher proportion and molecular weight of cellulose resin. More specifically, comparing Examples 1 to 4 and Comparative Example 1, it was confirmed that when the molecular weight of the cellulose resin was the same, a higher proportion of cellulose resin resulted in a higher heat resistance temperature. Furthermore, comparing Example 1 and Comparative Example 2, it was confirmed that when the proportion of cellulose resin was the same, a higher molecular weight of the cellulose resin resulted in a higher heat resistance temperature. Overall, Examples 1 to 4, which contained a good balance of cellulose resin and acrylic resin, were evaluated as excellent (rated A). Examples 1 to 4 contained 40% to 75% cellulose resin and 25% to 60% acrylic resin, and the molecular weight of the cellulose resin was 25,000 or more. It was confirmed that such a case is suitable for the coating layer 35.

[0037] <Other Embodiments> The present invention is not limited to the embodiments described above and in the drawings, and the following embodiments, for example, are also included in the technical scope of the present invention.

[0038] (1) The layer configuration of the lid material 30 can be changed as appropriate depending on the purpose. For example, the aluminum foil 33 is not limited to a single layer, but may be provided in multiple layers as shown in Figure 4. The base layer of the lid material 130 in Figure 4 has a configuration in which two aluminum foils 33A and 33B are bonded together by a resin insulating layer 37. In this way, each aluminum foil 33A and 33B can be made into a thin film, and one of the two sides of each aluminum foil 33A and 33B (for example, a matte surface suitable for forming the printed layers 32 and 34) can be placed on the side of the printed layers 32 and 34.

[0039] (2) The printed layers 32 and 34 are merely examples of intermediate layers, and the intermediate layers may be formed by methods other than printing.

[0040] (3) The size and shape of the sheet-like container 20, the number and spacing of the storage compartments 21 shown in the illustration are examples and can be changed as appropriate. The sheet-like container 20 and storage compartments 21 may also be configured to be detachable individually. [Explanation of Symbols]

[0041] 10: Press-through packaging (PTP), 20: Sheet container, 21: Compartment, 21A: Opening, 30, 130: Lid material (packaging material), 31: Heat-sealed layer, 32: First printing layer (intermediate layer), 33, 33A, 33B: Aluminum foil, 34: Second printing layer (intermediate layer), 35: Coating layer, T: Contents

Claims

1. Aluminum foil and The aluminum foil comprises a coating layer provided on one side of the aluminum foil, The aforementioned coating layer is made of a curable resin containing cellulose resin and acrylic resin, but not containing nitrocellulose resin or melamine resin. A packaging material wherein the mixing ratio of the cellulose resin and the acrylic resin in the curable resin is 40% to 55% for the cellulose resin and 45% to 60% for the acrylic resin, and the molecular weight of the cellulose resin is 25,000 to 30,000.

2. The packaging material according to claim 1, further comprising a heat-adhesive layer provided on the other side of the aluminum foil.

3. An intermediate layer visible from the outside is provided between the aluminum foil and the coating layer, and between the aluminum foil and the heat-bonding layer, The packaging material according to claim 2, wherein the intermediate layer does not contain nitrocellulose resin.

4. The packaging material according to claim 1 or claim 2, wherein the thickness of the aluminum foil is 6 μm or more and 35 μm or less.

5. A sheet-like container including a containment section in which the contents are contained, A press-through package comprising a packaging material according to claim 1 or claim 2, which is adhered to the sheet-like container so as to cover the opening of the storage section.

6. The press-through package according to claim 5, wherein the contents are pharmaceuticals or food products.

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