JP2022057387A - Tray type paper container - Google Patents

Abstract

To propose a tray-type paper container made mainly of paper, having a flat flange that improves airtightness with a lid material.SOLUTION: In a tray-type paper container formed from a single blank sheet composed of a laminate having a paper layer 3 and an inner surface resin layer 4, the blank sheet has a bottom plate 5 having a shape in which a regular octagon is stretched in a vertical direction and a horizontal direction, a rectangular corner plates 6 are continuously provided on each of the four unstretched sides of the bottom plate via a ridge-folding horizontal ruled line, an inverted trapezoidal side plates 7 are continuously provided on the other sides of the bottom plate via the ridge-folding horizontal ruled line, and flange parts 8 are continuously provided on each side plate via a valley fold ruled line. When the length of the bottom of the corner plate is C and the distance between the tip of the corner plate and the tip of a flange part is f, f>C/2 is satisfied.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tray-type paper container for storing food and the like, and more particularly to a tray-type paper container having a flat flange portion and excellent sealing performance by a lid material.

Attempts to replace plastic containers, which are the cause of marine pollution, with containers that use biodegradable paper as a main material, which is a reproducible resource, due to the growing awareness of preserving the global environment. Are various.

The tray-type container is roughly classified into a use as a tray and a use as a storage container with an opening sealed with a lid material. In the latter case, it is common to provide a horizontal flange portion on the peripheral edge of the opening so that the lid material can be easily sealed.

In the case of a plastic container, it is easy to form a horizontal and flat flange part, but in the case of a paper container, seams, wrinkles and steps are likely to occur in the flange part, so a flat flange part can be stably formed. It was not easy to form.

The blank for a tray container described in Patent Document 1 which is the application of the applicant is a conventional tray pattern paper container, in which pinholes are easily formed at the base of the flange portion at the corner portion where the standing walls are connected to each other, and liquid leakage occurs. It is an improvement of what sometimes happened.

The blank for tray containers described in Patent Document 1 is effective as a countermeasure against pinholes in the conventional corner portion by providing a small protrusion in the corner portion where a problem may occur. Since there is a step due to the overlap of paper in the flange portion, there is a possibility that a gap based on the thickness of the paper is generated between the lid material and the flange portion.

Japanese Unexamined Patent Publication No. 2000-25546

An object to be solved by the present invention is to propose a paper container having a tray-type paper container mainly made of paper, in which the flange portion is flattened to improve the airtightness with the lid material.

As a means for solving the above problems, the invention according to claim 1 is a tray-type paper container formed from a single blank sheet composed of a laminate having a paper layer and an inner surface resin layer, and is a blank sheet. Is a paper layer in which an inner resin layer is formed on the entire surface after the necessary punching is performed, and then punched into a predetermined shape. The blank sheet is a shape obtained by stretching a regular octagon in the vertical and horizontal directions. On each of the four unstretched sides of the bottom plate, rectangular corner plates are connected via mountain fold ruled lines, and on the other sides of the bottom plate, mountain fold ruled lines are provided. An inverted trapezoidal side plate is continuously provided via the side plate, and a flange portion is continuously provided on each side plate via a valley fold ruled line. A paper layer is provided between each corner plate and the side plate and the flange portion. When the length of the bottom of the corner plate is C and the distance between the tip of the corner plate and the tip of the flange is f, then f> C / 2. In molding, the tray-type paper container is characterized in that the tip portion and the flange portion of each side plate are folded inside each corner plate so that the tips of the respective side plates do not overlap each other.

In the tray paper pattern container according to the present invention, by examining the shape of the blank sheet, the flange portions on the four sides do not overlap with each other, so that the flange portions after molding do not have a step and the sealing performance of the lid material is improved. rice field.

Further, in the invention according to claim 2, in the blank sheet, the length of the bottom of the corner plate is C, the distance between the tip of the corner plate and the tip of the flange portion is f, and the thickness of the paper layer is t. The tray-type paper container according to claim 1, wherein f> C / 2 + 2t.

The invention according to claim 3 is characterized in that, at both ends of the valley fold ruled line demarcating the side plate and the flange portion, notches extending to the side plate and the flange portion are provided in the paper layer. Item 2. The tray-type paper container according to Item 1 or 2.

In the tray pattern paper container according to the present invention, since the flange portions on the four sides do not overlap with each other by examining the shape of the blank sheet, the flange portions after molding do not have a step due to the overlap of the laminated body, and the lid is not formed. The sealing performance of the material is improved.

In addition, since a blank sheet is used in which an inner resin layer is formed on the entire surface of the paper layer and then punched into a predetermined shape, there is a concern about water leakage in the tray-shaped paper container after molding. There is no.

As in the invention according to claim 2, when the length of the bottom of the corner plate is C, the distance between the tip of the corner plate and the tip of the flange portion is f, and the thickness of the paper layer is t in the blank sheet. By setting f> C / 2 + 2t, there is an effect that a gap between the flange portions at the corner portion is less likely to occur.

As in the invention according to claim 3, when the paper layer is provided with notches extending to the side plate and the flange portion at both ends of the valley fold ruled line demarcating the side plate and the flange portion, the most paper layer is provided. Since the paper layer in the portion where the paper is likely to overlap is removed in advance, there is an effect that the overlap between the flange portions and the overlap between the side plates are less likely to occur.

FIG. 1 is a schematic plan view of a tray-type paper container according to the present invention, showing a state in which the lid material is not sealed. FIG. 2 is a schematic cross-sectional view showing a cross section taken along the line AA of FIG. FIG. 3 is a schematic plan view showing a state in which the blank sheet of the tray-type paper container shown in FIG. 1 is viewed from the paper layer side. FIG. 4 is an enlarged view of the corner portion of the blank sheet shown in FIG. 3, and is an explanatory view of the length C of the bottom side of the corner plate and the distance f between the tip of the corner plate and the tip of the flange portion. FIG. 5 is a schematic cross-sectional view showing a cross section taken along the line BB'in FIG. 4, showing a state in which the paper layer is turned down. FIG. 6 is an enlarged view of a corner portion of a blank sheet in another embodiment of the tray pattern paper container according to the present invention, and is an explanatory view of a notch. FIG. 7 is a plan explanatory view showing a state in which the blank sheet shown in FIG. 6 is molded into a tray pattern paper container.

The tray pattern paper container according to the present invention will be described in detail with reference to the following drawings. FIG. 1 is a schematic plan view of the tray pattern paper container 1 according to the present invention, showing a state in which the lid material is not sealed. FIG. 2 is a schematic cross-sectional view showing a cross section taken along the line AA of FIG. FIG. 3 is a schematic plan view showing a state in which the blank sheet of the tray-type paper container shown in FIG. 1 is viewed from the paper layer side. FIG. 1 shows a state in which the tray pattern paper container 1 is viewed from the inner surface resin layer 4 side.

The tray pattern paper container 1 according to the present invention is a tray pattern paper container formed from one blank sheet (BL) made of a laminate 2 having a paper layer 3 and an inner surface resin layer 4. In the blank sheet, the inner surface resin layer 4 is formed on the entire surface of the paper layer 3 after the necessary punching is performed, and then the blank sheet is punched into a predetermined shape. The blank sheet has a bottom plate 5 having a shape in which a regular octagon is stretched in the vertical and horizontal directions, and the four unstretched sides of the bottom plate 5 are routed via mountain fold ruled lines e, f, g, and h, respectively. Rectangular corner plates 6 are connected in series.

The paper layer, which usually corresponds to the outside of the container, is printed and displayed on the surface side of the laminate. Therefore, a fold ruled line having a mountain on the paper layer side is a mountain fold ruled line, and a fold ruled line having a valley on the paper layer side is a valley fold ruled line. In FIG. 3, the mountain fold ruled line is displayed as a dotted line, and the valley fold ruled line is displayed as a alternate long and short dash line.

Inverted trapezoidal side plates 7 are connected to the other sides of the bottom plate 5 via mountain fold ruled lines a, b, c, and d, respectively, and valley fold ruled lines i, j, k, l are connected to each side plate. Flange portions 8 are continuously provided via the above.

The paper layer 3 is punched out between each corner plate 6 and the side plate 7 and the flange portion 8, and there is a portion of only the inner surface resin layer 4. In molding, the tip portion and the flange portion 8 of each side plate 7 are folded inside each corner plate 6 and molded so that the tips of the respective side plates do not overlap each other.

By preventing the flange portions 8 on the four sides from overlapping each other, the flange portions 8 after molding have a flat finish, and since there are no steps, pinholes do not occur when the lid material 10 is sealed, and the flange portions 8 are sealed. The sex has increased.

Further, since the blank sheet is formed by forming the inner surface resin layer 4 on the entire surface after the paper layer 3 is punched and then punched into a predetermined shape, the inner surface resin is used in the tray-shaped paper container after molding. Since the layer 4 exists continuously from the bottom surface to the flange portion, there is no concern about water leakage.

FIG. 4 is an enlarged view of a corner portion of the blank sheet (BL), and is an explanatory diagram of a length C of the bottom side of the corner plate 6 and a distance f between the tip of the corner plate 6 and the tip of the flange portion 8. Regarding the value of f, geometrically, by setting f = C / 2, the tips of the flange portions 8 should fit together exactly and no gap should be generated, but in reality, the thickness of the paper layer 3 and the thickness of the paper layer 3 Since the inner surface resin layer 4 has a thickness, it has been found that a gap is generated when f = C / 2. Even if a gap is created, pinholes will not occur as long as it is within a certain range.

If an extreme gap is created between the flange portions 8, a sealing defect will occur when the lid material is sealed. Therefore, by setting f> C / 2, the tips of the side plates 7 and the tips of the flanges 8 do not overlap each other on the corner plate 6 at the time of molding, and the gap is within the allowable range, so that the molding can be performed safely.

When the thickness of the paper layer is t, by further setting f> C / 2 + 2t, the gap becomes smaller and the safety is further increased.

FIG. 6 is an enlarged view of a corner portion of a blank sheet (BL) in another embodiment of the tray pattern paper container 1 according to the present invention, and is an explanatory view of a notch 9. Further, FIG. 7 is a plan explanatory view showing a state in which the blank sheet shown in FIG. 6 is molded into a tray pattern paper container.

This example is characterized in that notches 9 extending to the side plate 7 and the flange portion 8 are provided on the paper layer at both ends of the valley fold ruled line demarcating the side plate 7 and the flange portion 8. By doing so, the paper layer 3 in the portion where the paper layers are most likely to overlap is removed in advance, and there is an effect that the overlap between the flange portions 8 and the overlap between the side plates 7 are less likely to occur.

The material of the paper layer 3 is not particularly limited, but various paperboards, coated cardboards, carton base papers, cup base papers, and the like generally used for paper containers can be used.

The material used for the inner resin layer 4 can be selected according to the intended use of the tray-type paper container. For example, if microwave heating is required, polypropylene (PP) resin or polyethylene terephthalate having high temperature resistance can be selected. (PET) resin, polybutylene terephthalate (PBT) resin and the like are used. If high temperature resistance is not required, low density polyethylene resin (LDPE), medium density polyethylene resin (MDPE), linear low density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene- Ethylene resins such as α-olefin copolymers and ethylene-methacrylic acid resin copolymers, blended resins of polyethylene and polybutene, propylene-ethylene random copolymers, propylene-ethylene block copolymers, and propylene-α-olefins. Synthetic resins generally used as sealants such as copolymers can be used alone or in combination.

Hereinafter, the finished state when the distance f between the tip of the corner plate 6 and the tip of the flange portion 8 was actually changed was confirmed.

A blank sheet was punched out after a window was punched out from a cup base paper having a basis weight of 260 g / m2 and a portion corresponding to the upper side of the flange portion overlapping portion was attached, an inner surface resin layer was bonded to the inner surface side of the paper, and then a blank sheet was punched out. As the inner surface resin layer, a three-layer film of polyethylene resin 15 μm / polyethylene terephthalate resin 12 μm / polyethylene resin 30 μm was used. The thickness of the paper layer is 0.5 mm. The length C of the bottom of the corner plate is 20 mm. The distance f between the tip of the corner plate and the tip of the flange was set to 12 mm. This blank sheet was molded to produce a tray paper pattern container. The lid material was sealed on the flange to confirm the sealing performance.

A tray paper pattern container was produced in the same manner as in Example 1 except that the value of f was 11.5 mm, and the evaluation was performed in the same manner.

A tray paper pattern container was produced in the same manner as in Example 1 except that the value of f was 11 mm, and the evaluation was performed in the same manner.

A tray pattern paper container was prepared in the same manner as in Example 1 except that the value of f was set to 10.5 mm, and the evaluation was carried out in the same manner.

<Comparative Example 1>
A tray paper pattern container was produced in the same manner as in Example 1 except that the value of f was set to 10 mm, and the evaluation was performed in the same manner.

<Comparative Example 2>
A tray pattern paper container was prepared in the same manner as in Example 1 except that the value of f was set to 9.5 mm, and the evaluation was carried out in the same manner.

<Comparative Example 3>
A tray paper pattern container was produced in the same manner as in Example 1 except that the value of f was 9 mm, and the evaluation was performed in the same manner.

The above results are summarized in Table 1.

From the results in Table 1, it can be seen that the tray pattern paper container according to the present invention has excellent sealing performance at the flange portion.

1 ... Tray pattern paper container BL ... Blank sheet 2 ... Laminated body 3 ... Paper layer 4 ... Inner surface resin layer 5 ... Bottom plate 6 ... Corner plate 7 ... Side plate 8 ... Flange portion 9 ... Notch 10 ... Cover material C ... Length of the bottom of the corner plate f ... Distance between the tip of the corner plate and the tip of the flange portion t ... Paper Layer thickness a to h ... Mountain fold ruled line i to l ... Valley fold ruled line

Claims (3)

A tray-type paper container formed from a single blank sheet composed of a laminate having a paper layer and an inner surface resin layer.
The blank sheet is obtained by forming an inner resin layer on the entire surface after punching the paper layer as necessary, and then punching it into a predetermined shape.
The blank sheet has a bottom plate having a shape in which a regular octagon is stretched in the vertical and horizontal directions, and rectangular corner plates are continuously provided on each of the four unstretched sides of the bottom plate via a mountain fold ruled line. And
On the other sides of the bottom plate, inverted trapezoidal side plates are connected via mountain fold ruled lines, and on each side plate, flanges are connected via valley fold ruled lines.
The paper layer is punched out between each corner plate and the side plate and the flange portion, and there is only a portion of the inner surface resin layer.
When the length of the bottom of the corner plate is C and the distance between the tip of the corner plate and the tip of the flange is f, f> C / 2.
In molding, the tray-type paper container is characterized in that the tip and flange of each side plate are folded inside each corner plate so that the tips do not overlap each other. In the blank sheet, when the length of the bottom of the corner plate is C, the distance between the tip of the corner plate and the tip of the flange is f, and the thickness of the paper layer is t, f> C / 2 + 2t. The tray pattern paper container according to claim 1. The tray pattern paper container according to claim 1 or 2, wherein the paper layer is provided with notches extending to the side plate and the flange portion at both ends of the valley fold ruled line demarcating the side plate and the flange portion.

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