JP7484327B2 - Paper tray - Google Patents

Description

The present invention relates to paper trays. In particular, the present invention relates to paper trays formed using blanks based on paperboard, capable of storing, for example, frozen foods such as ice cream, or powdered materials.

Paper trays are used in retail settings such as supermarkets and convenience stores as food packaging materials, for example. They come in a variety of forms, but because they are based on paper, they are widely used not only because of their cost advantage, but also as an environmentally friendly packaging material.

Also, various configurations are possible depending on the contents. A thermoplastic resin layer is applied to the surface of the paper base material used as a blank to impart water resistance, and the thermoplastic resin layer can be sealed to form a three-dimensional paper tray. A lid can also be sealed to seal the entire tray.

However, unlike plastic-based trays, which are made by assembling flat blanks based on paper, there are areas where the blanks overlap when assembled.

Because this part is thick, there is a risk that this step will cause a seal defect when sealing the paper tray, and there have been problems with sealing. In particular, there have been calls for improvements in this regard, as there is a risk of leakage problems, which are considered to be a serious defect in packaging materials, especially for liquid contents.

For example, Patent Document 1 proposes a tray blank that can be used to form a paper tray by providing edges on a rectangular tray and providing tongues at the four corners of the rectangle to join the edges on two sides. However, in this case, it is unavoidable that a step will be created at the joint of the tongues due to overlapping, and there is a risk that the gaps caused by these steps will cause a lack of sealing and lead to leakage of the contents.

JP 2000-255546 A

The present invention was made in consideration of such circumstances, and aims to provide a paper tray that has no step at the joint of the flange formed from the edge piece and has good sealing properties.

As a means for solving the above problem, the invention described in claim 1 is
A paper tray made of a paper blank,
The paper blank is made of a backing paper and a thermoplastic resin layer formed on both sides of the backing paper or on the surface that will become the inside of the tray.
The paper tray is composed of a bottom, side panels, and a rim piece.
The side panels rise up and surround the bottom to form a tray.
The edge piece is continuous with the upper end of the side panel and parallel to the bottom surface to surround the periphery of the tray to form a flange;
The backing paper constituting the blank is cut at the corners of the tray between the side panels and the adjacent side panels so that the side panels do not overlap when the side panels are raised,
In addition, the gap between the edge pieces and the adjacent edge pieces is cut so that they do not overlap when the entire edge piece is formed.
The thermoplastic resin layer is laminated on both sides of the mount or on the inner surface of the tray, including the portion where the mount has been cut away;
The side panels that surround the bottom are connected to the adjacent side panels by a layer of thermoplastic resin that is formed in the area where the backing was removed.
Similarly, this is a paper tray, characterized in that the edge pieces and adjacent edge pieces are sealed and connected by a thermoplastic resin layer in the area where the backing paper has been cut away to form a tray.

The invention described in claim 2 is as follows:
The paper tray according to claim 1, characterized in that the thermoplastic resin layer is made of one or more of a polyethylene resin, a polypropylene resin, a polyethylene terephthalate resin, and a polybutylene terephthalate resin.

According to the present invention, it is possible to provide a paper tray with good sealing properties without any step at the joint of the flange formed from the edge piece.

The present invention is a paper tray made of paper blanks. The paper tray is composed of a bottom surface, side panels, and edge pieces. The side panels rise up and surround the bottom surface to form the tray, making the paper tray more environmentally friendly, highly water-resistant, and easy to form into a tray from a flat blank.

In addition, in the present invention, the edge pieces are continuous with the upper ends of the side panels and are parallel to the bottom surface, surrounding the tray to form a flange that surrounds the periphery of the paper tray. Since there are no steps in the flange due to overlapping blanks, it is possible to easily seal the lid material, resulting in a paper tray with better airtightness.

In other words, the backing paper that makes up the blanks is cut out at the corners of the tray so that there is no overlap between the side panels and the adjacent side panels when the side panels are erected, and the edge pieces are also cut out so that there is no overlap between the adjacent edge pieces when the entire edge piece is formed. This makes it possible to eliminate overlapping areas between the blanks when assembling the blanks into a paper tray to form a three-dimensional object.

The thermoplastic resin layer is laminated on both the front and back sides of the backing or on the inner surface of the tray, including the areas where the backing has been cut out, and the side panels that rise up around the bottom are sealed and connected to the adjacent side panels by the thermoplastic resin layer in the areas where the backing has been cut out. Similarly, the edge pieces are sealed and connected to the adjacent edge pieces by the thermoplastic resin layer in the areas where the backing has been cut out to form the tray, which makes it possible to assemble the paper tray without the blanks overlapping, and the lack of overlapping ensures flatness, so that even when a lid is attached to the paper tray and sealed to the flanges, the paper tray can be made to have good sealing properties.

According to the invention described in claim 2, the thermoplastic resin layer is made of one or more of polyethylene resin, polypropylene resin, polyethylene terephthalate resin, and polybutylene terephthalate resin, which is more suitable as a sealant when assembling the paper tray and allows the sealant to be designed according to the application of the paper tray. In particular, when polyethylene terephthalate resin or polybutylene terephthalate is selected, a paper tray with better heat resistance can be realized.

FIG. 1 is a schematic perspective view for explaining one embodiment of a paper tray according to the present invention. FIG. 2 is a schematic planar development view for explaining one embodiment of a paper tray according to the present invention. Figure 3 is a schematic planar development diagram of a backing sheet to explain that, at a corner of one embodiment of a paper tray according to the present invention, the backing sheet is cut between the side panels of the backing sheet and adjacent side panels so that they do not overlap when the side panels are raised, and that the backing sheet is cut between the edge pieces and adjacent edge pieces so that they do not overlap when the edge pieces are formed. FIG. 4 is a schematic plan view illustrating a window cutout portion of a backing paper in one embodiment of a paper tray according to the present invention. Figure 5 is a schematic plan view illustrating the state of a paper tray according to one embodiment of the present invention, in which thermoplastic resin is applied to both the front and back surfaces of the backing paper or the inner surface of the tray, after which punching is completed and the blank is completed.

The present invention will be described in more detail below with reference to Figures 1 to 5. However, the present invention is not limited to the examples shown here. The present invention is defined by the claims.

Figure 1 is a schematic perspective view illustrating one embodiment of a paper tray according to the present invention.

The present invention is a paper tray (100) formed from a paper blank. As shown in the perspective schematic diagram of one embodiment in Figure 1, it has a bottom plate (1) and is surrounded by side plates (2), and at the upper end of the side plate (2), a border piece (3) is formed that is continuous with the side plate (2) and parallel to the bottom surface (1).

The edge pieces (3) surround the periphery of the paper tray (100) to form a flange (4). Therefore, as can be seen from FIG. 1, the flange (4) is octagonal in shape and is an example made up of eight edge pieces (3).

In the example shown in FIG. 1, the bottom plate (1) is octagonal. Therefore, there are eight side plates (2) and eight edge pieces (3). The three-dimensional paper tray (100) formed by standing the side plates (2) upright can be used as an octagonal container capable of storing contents.

In the present invention, the paper blanks are made of a backing paper and a thermoplastic resin layer formed on both sides of the backing paper or on the surface that will become the inside of the tray, and the three-dimensional formation of the paper tray can be achieved by sealing and adhering the thermoplastic resin layer. In addition, by covering both sides of the blanks or the surface that will become the inside of the tray with a thermoplastic resin layer, it is possible to impart excellent water resistance to the paper tray (100).

In addition, the edge piece (3) formed as the flange (4) of the paper tray (100) allows a lid material to be sealed to this portion, thereby sealing the entire paper tray (100).

This paper tray (100) is made of paper as a base material, making it an excellent environmentally friendly packaging material, and can also be made airtight if necessary, making it a highly convenient paper tray (100) that can be widely used.

In addition, the present invention can eliminate the overlap of blanks when forming a solid shape, which has traditionally been a drawback of paper trays (100). In particular, it is possible to eliminate the overlap of the flange (4) portion that surrounds the periphery of the paper tray (100) and is formed by the edge piece (3), making it possible to make it flat. Therefore, it is possible to make the paper tray (100) excellent in terms of sealing properties.

Figure 2 is a schematic plan view illustrating one embodiment of a paper tray according to the present invention.

The present invention is a paper tray (100) formed from a paper blank. The blank is made of a backing paper as a base material, with a thermoplastic resin layer on both sides or on the inner surface of the tray. The side panels (2) are raised and molded into a three-dimensional shape to form the paper tray (100), which is used as a container capable of storing contents. The planar development schematic diagram (9) of the example shown in Figure 2 shows only the backing paper portion of the blank.

As shown in the schematic plan view (9) of the example shown in Figure 2, the paper tray (100) has a bottom surface (1) at the center and side panels (2) that rise up and surround the bottom surface (1), and the side panels (2) have edge pieces (3) that are continuous with the upper end of the side panels (2) and parallel to the bottom surface (1).

That is, in the embodiment shown in FIG. 2, the bottom plate (1) has four sides and has four corners (10) of the paper tray (100). Therefore, the bottom plate (1) is octagonal and has one side, and the side plate (2) has eight sides. Also, the edge piece (3) is connected to the upper end of each side plate (2), and has eight sides.

In addition, in FIG. 2, the fold line (5) between the bottom surface (1) and the side panel (2) is a valley fold, and the fold line (6) between the side panel (2) and the edge piece (3) is a mountain fold, so that the paper tray (100) rises up toward the front of FIG. 2 to become three-dimensional.

At this time, unlike the flat development view of conventional blanks, a V-shaped cut-out portion (11) is provided so that there are no overlapping portions of the blanks when the blanks are made into a three-dimensional object. This cut-out portion (11) is cut out of the paper base material at the corner (10) of the paper tray (100) so that the side panels (2) do not overlap when the side panels (2) are erected, and the edge pieces (3) are cut out so that the edge pieces (3) do not overlap when the edge pieces (3) are formed.

Therefore, when the fold line (5) between the bottom surface (1) and the side panel (2) is folded in a valley to raise the side panel (2), the V-shaped cut-out portion between the side panels (2) is closed, and the side panels (2) become continuous.

In addition, if the fold line (6) between the side panel (2) and the edge piece (3) is folded in a mountain fold to make the edge piece (3) parallel to the bottom surface (1), the edge pieces (3) will also be continuous with each other to form a flange (4) that surrounds the periphery of the paper tray (100).

Incidentally, when the paper tray (100) is formed into a three-dimensional shape,
The edge piece (3), which surrounds the periphery of the paper tray (100) and is a horizontal surface, can seal the lid material and edge piece (3) when placing a lid material on the paper tray (100), thereby sealing the entire paper tray (100).

Figure 3 is a schematic planar development of the backing to illustrate that, at the corner of one embodiment of the paper tray according to the present invention, the backing has been cut away between the side panels of the backing and the adjacent side panels so that they do not overlap when the side panels are raised, and that the backing has been cut away between the edge pieces and the adjacent edge pieces so that they do not overlap when the edge pieces are formed.

As described above, in the present invention, the backing (20) forming the blank is cut between the side panel (2) and the adjacent side panel (8) so that they do not overlap when the side panel (2) is erected, and the backing (20) is cut between the edge piece (3) and the adjacent edge piece (3) so that they do not overlap when the edge piece (3) is formed.

There are no particular limitations on the material of the backing paper (20), and ordinary paper or cardboard can be used, and the thickness and paper quality can be appropriately selected taking into consideration the required quality and application of the paper tray (100).

In the example shown in FIG. 3, the cut-out portions (11) of the mount (20) are punched out into two adjacent windows (12), forming four windows (12) at the four corners of the mount (20).

For ease of understanding, the position of the window cutout (12) is shown superimposed on a plan view diagram indicated by dashed lines.

Figure 4 is a schematic plan view illustrating the window cutout portion of the backing paper in one embodiment of the paper tray according to the present invention.

As mentioned above, the window cutouts (12) shown in FIG. 3 are located at the four corners of the backing paper (20). The relationship between the window cutouts (12) for providing the cut-out portions (11) and the backing paper (20) is as shown in FIG. 4.

The blank for the paper tray (100) according to the present invention is obtained by providing a thermoplastic resin layer on both the front and back surfaces or on the inner surface of the tray of the backing paper (20) provided with the window cutout portion (12) in this manner. That is, in the present invention, the thermoplastic resin layer is laminated on the front and back surfaces of the backing paper (20), including the window cutout portion (12) of the backing paper (20).

In this way, by laminating the backing paper (20) and the thermoplastic resin layer and then punching out the blanks for the paper tray (100), it is possible to more accurately and productively produce blanks for the paper tray according to the present invention.

To create the blanks, the four corners (13) are separated and removed from the laminated thermoplastic resin backing (20) shown in Figure 4.

Figure 5 is a schematic plan view of one embodiment of the paper tray of the present invention, showing the state after punching is completed and the blank is completed after applying thermoplastic resin to both sides of the backing paper or the surface that will become the inside of the tray.

In the finished blank (40) for the paper tray (100) according to the present invention,
The mount (1) is cut as shown in the planar development (9) in FIG. 2, and a thermoplastic resin layer (30) is provided on both the front and back surfaces or on the surface that will become the inner surface of the tray.

The thermoplastic resin layer (30) covers not only the paper portion, but also the cut-out portion (11) that is provided so that the paper portions of the blank (40) do not overlap, and this portion forms a window cutout portion (12) in the backing (20), but only the thermoplastic resin layer (30) is laminated on both the front and back surfaces or on the surface that will become the inside of the tray.

In the blank (40) shown in FIG. 5, the paper tray (100) has a bottom surface (1) at its center, and the side panels (2) that rise up around the bottom surface (1) have edge pieces (3) that are continuous with the upper ends of the side panels (2) and parallel to the bottom surface (1). In FIG. 5, the fold line (5) between the bottom surface (1) and the side panels (2) is a valley fold, and the fold line (6) between the side panels (2) and the edge pieces (3) is a mountain fold, so that the paper tray (100) rises to the front side of FIG. 5 to become three-dimensional.

At this time, at the corners (10) of the paper tray (100), the thermoplastic resin layer (30) in the area where the backing (20) has been cut away seals between the side panels (2) and the adjacent side panels (2), and similarly, the thermoplastic resin layer (30) in the area where the backing (20) has been cut away also seals between the edge pieces (3) and the adjacent edge pieces (3), forming the paper tray (100). For example, heat sealing can be used for this sealing.

The thermoplastic resin layers (30) are stacked so that they face each other, and are bonded to each other by applying heat and pressure to heat seal, making it possible to bond them to each other.

As the material for the thermoplastic resin layer (30), polyolefin-based resins are generally used among thermoplastic resins. Specifically, ethylene-based resins such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-methacrylic acid resin copolymer, blend resins of polyethylene and polybutene, and polypropylene-based resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer can be used.

The thermoplastic resin layer (30) can be formed by forming a film of molten resin using an extruder or the like and forming a layer on the mount (20). Alternatively, it is also possible to form the thermoplastic resin layer (30) on both sides or one side of the mount (20) by laminating a material that has already been formed into a film.

For this thermoplastic resin layer (30), in addition to the aforementioned polyethylene resin and polypropylene resin, one or more of polyethylene terephthalate resin and polybutylene terephthalate resin can be used. These can be appropriately selected and used depending on the application and required quality of the paper tray (100).

In particular, when polyethylene terephthalate resin or polybutylene terephthalate resin is used, the paper tray (100) has high heat resistance, for example, when used in applications involving microwave heating.

In this way, according to the present invention, it is possible to provide a paper tray with good sealing properties, without any step at the joint of the flange formed from the edge piece.

The present invention will be explained in more detail below with reference to Example 1 and Comparative Example 1. However, the present invention is not limited to the examples shown here. The present invention is defined by the claims.

For the evaluation, a paper tray is created, filled with the contents, and then the lid is sealed. The tray is then sealed and tilted to observe whether the contents leak.

Example 1
A window was created in the base paper for a cup having a basis weight of 260 g/ ^m2 , and polypropylene resin was extruded and laminated to a thickness of 30 μm on the surface of the backing paper. Polypropylene resin was extruded and laminated to a thickness of 40 μm on the surface that would become the inside of the paper tray. This sheet was cut and punched out to produce the blanks shown in FIG. 5.

Blanks for a paper tray according to the present invention shown in Figure 5 were assembled to create a paper tray with the appearance shown in Figure 1, which was then filled with ice cream and sealed with a lid to seal the paper tray.

When the container was inverted and tilted to observe whether the contents were leaking from the lid and flange, no leakage was observed even after 180 minutes had passed.

This result is believed to be due to the fact that in the blanks that make up the paper tray of Example 1, the portion of the backing paper that has been cut out according to the present invention is provided, so that the blanks do not overlap at the flange portion, making it flat and providing a strong seal for the lid material.

<Comparative Example 1>
A polypropylene resin was extruded to a thickness of 30 μm and laminated on the surface of the base paper of a cup having a basis weight of 260 g/ ^m2 . A polypropylene resin was extruded to a thickness of 40 μm and laminated on the surface that will become the inside of the paper tray. This sheet was cut and punched to create blanks for conventional paper trays.

These conventional blanks for paper trays were assembled to create a paper tray. The assembled paper tray had no cut-out portions, and some of the blanks overlapped the flanges. The paper tray was filled with ice cream, and a lid was sealed to seal the paper tray.

The container was inverted and tilted to observe whether the contents were leaking from the lid and flange, and leakage was confirmed after 30 minutes.

This result is thought to be due to the fact that the blanks constituting the paper tray of Comparative Example 1 do not have the cut-out portion of the backing paper according to the present invention, so the blanks overlap in the flange area, creating a step that inhibits the sealing of the lid material.

In this way, it was verified that the present invention makes it possible to provide paper trays with good sealing properties, without any step at the joint of the flange formed from the edge piece.

1... Bottom plate 2... Side plate 3... Edge piece 4... Flange 5... Fold line 6... Fold line 10... Corner 11... Cut-out portion 12... Window cut-out portion 13... Removed portion 20... Backing 30... Thermoplastic resin layer 40... Blank 100... Paper tray

Claims (2)

A paper tray made of a paper blank,
The paper blank is made of a backing paper and a thermoplastic resin layer formed on both sides of the backing paper or on the surface that will become the inside of the tray.
The paper tray is composed of a bottom, side panels, and a rim piece.
The side panels rise up and surround the bottom to form a tray.
The edge piece is continuous with the upper end of the side panel and parallel to the bottom surface to surround the periphery of the tray to form a flange;
The backing paper constituting the blank is cut at the corners of the tray between the side panels and the adjacent side panels so that the side panels do not overlap when the side panels are raised,
In addition, the gap between the edge pieces and the adjacent edge pieces is cut so that they do not overlap when the entire edge piece is formed.
The thermoplastic resin layer is laminated on both sides of the mount or on the inner surface of the tray, including the portion where the mount is cut out when the mount is laid out in a plane ;
The side panels that surround the bottom are connected to the adjacent side panels by a layer of thermoplastic resin that is formed in the area where the backing was removed.
Similarly, the edge pieces are sealed and connected to each other by the thermoplastic resin layer at the portion where the backing paper is cut away to form a tray .
A paper tray in which the space between adjacent edge pieces is sealed by heat sealing a thermoplastic resin layer in the area where the backing paper has been cut away . The paper tray according to claim 1, characterized in that the thermoplastic resin layer is made of one or more of polyethylene resin, polypropylene resin, polyethylene terephthalate resin, and polybutylene terephthalate resin.