JP2021054437A - Sheet-molded container and sheet material - Google Patents

Abstract

To provide a sheet-molded container formed by press molding a sheet material including paper, simply suppressed in generation of static electricity and reduced in environmental load.SOLUTION: A sheet-molded container 10 is press-molded from a sheet material having a paper layer and a cellophane layer and not having a resin film layer. The cellophane layer forms an inner surface of the container. Cellophane is used as a material for imparting water-resistance and oil-resistance to the container 10, instead of a conventional resin film, to thereby hardly cause static electricity. As a result, sticking of the sheet-molded containers 10 overlapping with each other in a packaged state is suppressed easily without needing a static eliminator, allowing easy separation of the container one by one, to thereby improve workability. Attachment of dust to the container 10 is also suppressed, providing a preferable sanitary state. Use of vegetable pulp as a raw material of the cellophane reduces environmental load.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sheet-molded container suitable for storing food and a sheet material for forming the sheet-molded container.

A sheet-molded container made by press-molding a sheet material and suitable for storing food is known. As the sheet material, those in which paper and a resin film are laminated, and those in which only a resin film is laminated alone or in a plurality of types as in Patent Documents 1 and 2 are widely used.

A sheet material obtained by laminating paper and a resin film has an advantage in that the amount of fossil fuel used can be reduced as compared with a sheet material consisting of only a resin film. In the sheet material composed of paper and a resin film, the resin film layer constitutes the inner surface of the sheet molding container, that is, the surface in contact with food, and imparts a water and oil resistance function to the molding container.

Japanese Unexamined Patent Publication No. 2008-265809 Japanese Unexamined Patent Publication No. 2010-11423

Since this type of sheet molding container is press-molded with the sheet materials stacked in consideration of production efficiency, etc., it is often packaged in a state where many sheets are stacked, and end users It will be peeled off one by one and used.
However, when the sheet material of the sheet molding container contains a resin film, it is easily charged with static electricity due to friction due to the material when it is taken out for transportation or use, and especially when combined with paper, an aluminum foil. Compared with the case of combining with a metal foil such as, the generation of static electricity is remarkable.

When the containers are charged with static electricity in this way, the overlapping sheet molding containers are attracted to each other, and it is not easy to peel them off one by one at the time of use, which deteriorates workability.
Further, when static electricity is applied, dust is adsorbed on the sheet molding container, which is not preferable in terms of hygiene.

For this reason, in-site measures may be taken to remove static electricity by controlling the humidity during manufacturing or storage, or by using a static eliminator.
Further, as in Patent Documents 1 and 2, attempts have been made to apply antistatic processing to the resin film, but in any case, the number of steps increases and the production efficiency deteriorates.

Furthermore, when the sheet material of the sheet molding container contains not only paper but also a resin film, the amount of fossil fuel used is reduced compared to the sheet material made entirely of resin film, but it is environmentally friendly. There is also the problem that the load is still large.

Therefore, the problem to be solved by the present invention is to easily suppress the generation of static electricity and further reduce the burden on the environment in a sheet molding container formed by press molding a sheet material containing paper.

In order to solve the above-mentioned problems, the sheet molding container according to the invention is press-molded from a sheet material having a paper layer and a cellophane layer and not a resin film layer, and the cellophane layer forms the inner surface of the container. It was configured to be.

Since the material for imparting water and oil resistance to the container is cellophane instead of the resin film, static electricity is less likely to be applied due to the material. As a result, the overlapping sheet molding containers are suppressed from sticking to each other, and it becomes easy to peel them off one by one at the time of use, and workability is improved. In addition, the adsorption of dust to the sheet molding container is suppressed, which is also preferable in terms of hygiene.
Unlike resin film, cellophane itself is less likely to be charged with static electricity, so there is no need to control humidity, use static eliminators, or apply antistatic treatment, and the number of processes can be reduced, resulting in production efficiency. Can be improved.
Since cellophane is made from vegetable pulp, it has a small impact on the environment.
The sheet-molded container according to the present invention may have a layer other than the resin film, such as a printing layer and an adhesive layer, between the paper layer and the cellophane layer, or on the outer surface side of the container of the paper layer.

In the sheet molding container according to the present invention, it is preferable to adopt a configuration in which the surface resistivity (sheet resistance) is 1.00 × 10 ⁴ Ω / sq to 1.00 × 10 ^{12 Ω / sq on the inner surface of the container.}
With this configuration, the generation of static electricity on the inner surface of the container can be particularly suppressed. If the surface resistivity of the inner surface of the container ^{exceeds 1.00 × 10 12} Ω / sq, it becomes easy to be charged, and it may not be easy to peel off the overlapping sheet-molded containers one by one. If is less than 1.00 × 10 ⁴ Ω / sq, it is difficult to charge, but it is easy to dielectric and may cause other inconveniences.
A more preferable range of the surface resistivity of the inner surface of the container is 1.00 × 10 ⁸ Ω / sq to 1.00 × 10 ¹¹ Ω / sq.

In the sheet molding container according to the present invention, it is more preferable to adopt a configuration in which the surface resistivity (sheet resistance) is 1.00 × 10 ⁴ Ω / sq to 1.00 × 10 ^{12 Ω / sq even on the outer surface of the container.}
With this configuration, it is possible to particularly suppress the generation of static electricity not only on the inner surface of the container but also on the outer surface of the container.
The more preferable range of the surface resistivity of the outer surface of the container is 1.00 × 10 ⁸ Ω / sq to 1.00 × 10 ¹¹ Ω / sq.

In the sheet molding container according to the present invention, it is preferable that the cellophane of the cellophane layer adopts a configuration in which the cellophane is a plain cellophane that has not been subjected to a moisture-proof treatment.
With this configuration, unlike the moisture-proof cellophane, it does not have a resin coat layer, so that the generation of static electricity can be further suppressed.

In the sheet molding container according to the present invention, a configuration having a release coat layer made of vegetable wax on the outer surface of the container can be adopted.
With such a configuration, the releasability between the overlapping sheet molding containers is improved, so that it becomes easier to peel off the sheets one by one at the time of use.
Since it uses vegetable wax, it has a small impact on the environment unlike wax using petroleum raw materials, and there are few problems even if it is taken orally.
Here, the sheet-molded container according to the invention is suitably used for storing food.

Further, in order to solve the above-mentioned problems, the sheet material for forming the sheet molding container has a paper layer and a cellophane layer for forming the inner surface of the sheet molding container, and does not have a resin film layer. It is preferable to adopt a configuration in which ^{the surface resistivity is 1.00 × 10 4} Ω / sq to 1.00 × 10 ¹² Ω / sq on the surface on the side of the cellophane layer.
According to the inventor's confirmation, the surface resistivity hardly changes before and after forming the sheet molding container from the sheet material.
Therefore, by adjusting in advance so that the surface resistivity of the sheet material falls within the above range, it is easy to set the surface resistivity of the inner surface of the container in the sheet molding container to a suitable range in which static electricity is less likely to be generated. it can.

Since the present invention is configured as described above, the generation of static electricity in the sheet molding container is easily suppressed, and the load on the environment is also reduced.

Perspective view of the sheet molding container of the embodiment Sectional drawing of sheet material of embodiment

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The sheet molding container of the embodiment shown in FIG. 1 is created by press molding the sheet material of the embodiment shown in FIG. 2, and the generation of static electricity is easily suppressed.

As shown in FIG. 1, the sheet forming container 10 of the embodiment has a bottom wall 11 having a circular shape in a plan view and a peripheral wall 12 extending from the peripheral edge of the bottom wall 11 and rising upward, and is open upward.
The bottom wall 11 of the sheet forming container 10 is flat, and a large number of wrinkles 12a extending in the vertical direction are formed on the entire circumference of the peripheral wall 12.
The sheet molding container 10 can store food from above in the storage space partitioned by the bottom wall 11 and the peripheral wall 12.

The dimensions of the sheet molding container 10 are not particularly limited, but the dimensions suitable for storing foods such as side dishes contained in the lunch box are an opening diameter of 50 to 80 mm, a bottom wall 11 diameter of 30 to 60 mm, and a height. A diameter of 15 to 25 mm can be exemplified.
The shape of the bottom wall 11 is not limited to a circular shape in a plan view, and may be an elliptical shape in a plan view, an oval shape in a plan view, or the like.
Further, the shape of the peripheral wall 12 is not limited to the one that extends from the bottom wall 11 and rises, and may rise substantially perpendicular to the bottom wall 11, for example. The form of the wrinkles 12a on the peripheral wall 12 is also not limited. For example, when the bottom wall 11 is oval in a plan view, wrinkles may be formed only at the rounded corners.
The sheet molding container 10 may have elements other than the bottom wall 11 and the peripheral wall 12, for example, a flange.

As shown in FIG. 2, the sheet material 10'of the embodiment is formed by laminating and integrating the paper layer 10a and the cellophane layer 10b by the adhesive layer 10c. The sheet material 10'does not have a resin film layer.
Since the sheet material 10'does not have a resin film layer and both the paper layer 10a and the cellophane layer 10b are made of vegetable pulp as a raw material, the load on the environment is small.
The sheet forming container 10 is formed by press-molding the sheet material 10'using a mold similar to the conventional one in a state where a large number of sheets are stacked.

Here, in the sheet molding container 10, the cellophane layer 10b is the inner surface of the container, and the paper layer 10a is the outer surface of the container.
The sheet molding container 10 is completed in a state where a large number of sheets are overlapped, packaged and shipped in that state, derived from the above-mentioned manufacturing method.
Since the cellophane of the cellophane layer 10b has a property of being less susceptible to static electricity than a resin film or the like, static electricity is less likely to be generated even if the overlapping sheet molding containers 10 rub against each other during transportation or use. ..
Therefore, it is suppressed that the overlapping sheet molding containers 10 are attracted to each other by static electricity, and it is easy to peel off one by one at the time of use, and the workability is good.

The paper layer 10a and the cellophane layer 10b may be composed of a single layer, or may be configured by laminating different types of paper or cellophane in a plurality of layers depending on the properties of the food to be stored and the like.
The types of paper and cellophane constituting the paper layer and cellophane layer are not particularly limited, and examples of paper include pure white paper and oil-resistant paper, and examples of cellophane include plain cellophane (PT) and moisture-proof cellophane (MST).
As the cellophane, unlike the moisture-proof cellophane, the plain cellophane is preferable because it is not coated with a moisture-proof coating by resin, so that static electricity is less likely to be generated and the environmental load is smaller. Examples of such cellophane include plain cellophane manufactured by Futamura Chemical Co., Ltd. and plain cellophane manufactured by Rengo Co., Ltd.
The basis weight of the paper and the thickness of the cellophane are not particularly limited, and examples thereof include a basis weight of paper of 10 to 150 g / m ² and a basis weight of cellophane of 30 to 60 g / m ² .
If the basis weight of paper or cellophane exceeds the upper limit of the above numerical range, molding defects are likely to occur during press molding, and if the basis weight is below the lower limit of the above numerical range, tearing or the like is likely to occur during press molding. Become.

Further, the paper layer 10a and the cellophane layer 10b are printed, so that another layer such as a printing layer, which is different from the resin film, is formed between the paper layer 10a and the cellophane layer 10b. It may be intervening. The type of ink in the printing layer is not particularly limited, but biomass ink is preferable because it has a small impact on the environment.
Further, the surface of the paper layer 10a opposite to the laminated surface with the cellophane layer 10b (the outer surface of the container in the sheet molding container 10) is another layer such as a second cellophane layer or a release coat layer. A layer different from the resin film may be provided.
When the release coat layer is provided, it becomes easy to peel off the sheet molding containers 10 one by one at the time of use in the state of being overlapped as described above. It is preferable that the release coat layer is composed of a vegetable wax such as carnauba wax because it has a small burden on the environment and has a small adverse effect when taken orally with food. The coating amount of the release coat layer is not particularly limited, and the coating amount may be 0.1 to 0.2 g / m ² .

The type and bonding mode of the adhesive in the adhesive layer 10c are not particularly limited, and urethane-based dry laminate can be exemplified.
Of these, biomass dry laminating is preferable because it has a small impact on the environment.

The surface resistivity (sheet resistance) of the front and back surfaces of the sheet material 10'is preferably 1.00 × 10 ⁴ Ω / sq to 1.00 × 10 ¹² Ω / sq, preferably 1.00 ×. and more preferably from 10 ⁸ Ω / sq is 1.00 × ^{10 11 Ω} / sq.
According to an experiment conducted by the present inventor, the surface resistivity of the sheet material 10'is hardly changed before and after the press molding, and the surface resistivity of the sheet material 10'defines the surface resistivity of the sheet molding container 10 as it is. Therefore, by adjusting the surface resistivity of the sheet material 10'within a predetermined range, it is possible to control the surface resistivity of the finished sheet molding container 10.
However, since there is a concern that the surface resistivity of a portion where a large number of wrinkles 12a are formed such as the peripheral wall 12 may change slightly, the surface resistivity measured here on a flat surface such as the bottom wall 11 is measured. It shall be said.
By setting the surface resistivity within the above range, the generation of static electricity and the like can be further suppressed. If the surface resistivity exceeds the above numerical range, it becomes easy to be charged, and it may not be easy to peel off the overlapping sheet molding containers one by one. Further, when the surface resistivity is less than the above numerical range, it is difficult to be charged, but it is easily dielectriced, and various inconveniences may occur.
Since the back surface of the sheet material 10'is composed of a paper layer like the back surface of the sheet material in which the conventional resin film layer and the paper layer are laminated, it is expected that the surface resistivity thereof will not change significantly from the conventional one. To. Therefore, only the surface resistivity on the surface of the sheet material 10'may be specified or adjusted.

Hereinafter, the content of the invention will be further clarified by giving examples and comparative examples of the present invention.
As shown in Table 1, the sheet materials of Example 1, Comparative Example 1 and Comparative Examples 3 to 9, and the sheet molding containers of Example 2 and Comparative Example 2 were prepared.

In Table 1, the left side corresponds to the front surface of the sheet material (inner surface in the sheet molding container), and the right side corresponds to the back surface of the sheet material (outer surface in the sheet molding container). The cellophane is plain cellophane manufactured by Futamura Chemical Co., Ltd. (trade name: Taiko cellophane, product number: PL basis weight 30 g / m ² ), the paper is white silver manufactured by Nippon Paper Co., Ltd., and the printing ink is manufactured by Toyo Ink Co., Ltd. The Riolfa S series used a dry laminating adhesive (product number: TM329 / CAT8B) manufactured by Toyo Morton Co., Ltd. for the dry laminate, and a carnauba wax manufactured by Leader Co., Ltd. for the release coat. The amount of carnauba wax applied is 0.18 g / m ² .
Further, PET stands for polyethylene terephthalate, PBT stands for polybutylene terephthalate, PE stands for polyethylene, and PBS stands for polybutylene succinate (biodegradable plastic).
The sheet-molded containers of Example 2 and Comparative Example 2 have the shape shown in FIG. 1, and the dimensions are an opening diameter of about 70 mm, a bottom wall diameter of about 45 mm, and a height of about 20 mm.

For the sheet materials and sheet molding containers of these Examples and Comparative Examples, the surface resistivity (sheet resistance: Ω / sq) of the front and back surfaces is measured by the surface resistivity measuring instrument (electrode: 20048E RESISTIVITY CELL main body: 4339A HIGH RESISTANCE) of Hulett Packard. It was measured using METER).
As the measurement conditions, the voltage was set to 500 V, the load applied to press the sheet material and the sheet molding container of the examples and comparative examples against the electrodes was 5 kg, and the resistivity 1 minute after the start of measurement was used as the measured value. ..
The results are shown in Table 2.

From Table 2, it was found that in the examples, the sheet resistance on the surface was smaller than that in the comparative example, and above all, the sheet resistance on the surface was smaller than that in the comparative example coated with antistatic coating, and the generation of static electricity was sufficiently suppressed. Further, in the examples, it was found that the sheet resistance was not so small as to be dielectric.
From the comparison between Example 1 and Example 2 and the comparison between Comparative Example 1 and Comparative Example 2, it was found that the value of the sheet resistance hardly changed before and after the press molding.

Next, the sheet-molded container of Example 2 was subjected to a water and oil resistance test.
As a water resistance test, water was put into the sheet molding container of Example 2, and the presence or absence of water penetration was observed over time.
As a result, no infiltration was observed after 8 hours, and the bottom wall was slightly moist after 24 hours.
As an oil resistance test, cooking oil was put into the sheet-molded container of Example 2, and the presence or absence of oil penetration was observed over time.
As a result, no infiltration was observed at any of the time points after 8 hours and 24 hours.
From the above results, it was found that there is no problem in terms of water resistance and oil resistance when using the sheet-molded container of the example in applications such as lunch boxes where stored items are consumed in a relatively short time (within 24 hours). ..

Next, the sheet molding container of Example 2 was subjected to a heat resistance test.
As the heat resistance test 1, two sheet-molded containers of Example 2 are prepared, vinegared food (containing acetic acid) and potato salad (containing oil) are stored in each, and these foods are carbonized using a microwave oven. It was overheated to and the condition of the container was observed.
As a result, neither penetration into the container nor delamination of the container was observed.
As a heat resistance test 2, mayonnaise (containing acetic acid and oil) was placed in the sheet-molded container of Example 2, heated at 200 ° C. for 25 minutes using an oven, and the state of the container was observed.
As a result, neither penetration into the container nor delamination of the container was observed.
From the above results, it was found that the sheet-molded container of the example had no problem in terms of heat resistance during normal cooking.

The embodiments and examples disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is indicated by the scope of claims and includes all modifications and modifications within the scope of claims and in the sense equivalent thereto.
For example, in the embodiments and examples, the stored material of the sheet-molded container is used as food, but the sheet-molded container can also be used for storage purposes other than food such as industrial parts.

10 Sheet molding container 10'Sheet material 10a Paper layer 10b Cellophane layer 10c Adhesive layer 11 Bottom wall 12 Peripheral wall 12a Wrinkles

Claims (7)

A sheet molding container formed by press molding a sheet material.
The sheet material has a paper layer and a cellophane layer, does not have a resin film layer, and has no resin film layer.
A sheet-molded container in which the cellophane layer constitutes the inner surface of the container. The sheet molding container according to claim 1, wherein the surface resistivity is 1.00 × 10 ⁴ Ω / sq to 1.00 × 10 ^{12 Ω / sq on the inner surface of the container.} The sheet molding container according to claim 2, wherein the surface resistivity is 1.00 × 10 ⁴ Ω / sq to 1.00 × 10 ^{12 Ω / sq even on the outer surface of the container.} The sheet-molded container according to any one of claims 1 to 3, wherein the cellophane of the cellophane layer is a plain cellophane that has not been subjected to a moisture-proof treatment. The sheet-molded container according to any one of claims 1 to 4, which has a release coat layer made of vegetable wax on the outer surface of the container. The sheet-molded container according to any one of claims 1 to 5, which is for storing food. A sheet material for forming a sheet molding container by press molding.
It has a cellophane layer and a paper layer for forming the inner surface of the sheet molding container, and does not have a resin film layer.
^{A sheet material having a surface resistivity of 1.00 × 10 4} Ω / sq to 1.00 × 10 ¹² Ω / sq on the surface on the side of the cellophane layer.

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