US20240286791A1

US20240286791A1 - Packing box

Info

Publication number: US20240286791A1
Application number: US18/588,304
Authority: US
Inventors: Haoki Fushimi; Sanshiro Takeshita
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2023-02-27
Filing date: 2024-02-27
Publication date: 2024-08-29
Also published as: JP2024121607A

Abstract

A packing box includes a corrugated cardboard box 3 that includes first side wall portions 7 and second side wall portions 9 and in which a vertical ridge line is formed between each of the first side wall portions 7 and each of the second side wall portions 9 with the corrugated cardboard box 3 assembled in a box shape and a reinforcing member 5 that is made of paper having a basis weight of 110 g/m²or more and is attached to the corrugated cardboard box 3 along a ridge line portion 29 that becomes the vertical ridge line with the corrugated cardboard box 3 assembled in a box shape. The reinforcing member may have a basis weight of 270 g/m²or more.

Description

The present application is based on, and claims priority from JP Application Serial Number 2023-028800, filed Feb. 27, 2023, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a packing box.

2. Related Art

JP-A-2011-161659 discloses a conventional corrugated cardboard box in which portions that become ruled line corners when the corrugated cardboard box is assembled in a box shape are coated with a paper-strengthening agent.
The corrugated cardboard box as described above in which portions that become ruled line corners when the corrugated cardboard box is assembled in a box shape are coated with a paper-strengthening agent cannot have sufficient strength.

SUMMARY

A packing box according to an aspect of the present disclosure includes a corrugated cardboard box that includes first side wall portions and second side wall portions and in which a vertical ridge line is formed between each of the first side wall portions and each of the second side wall portions with the corrugated cardboard box assembled in a box shape and a reinforcing member that is made of paper having a basis weight of 110 g/m²or more and is attached to the corrugated cardboard box along a ridge line portion that becomes the vertical ridge line with the corrugated cardboard box assembled in a box shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a developed view of a corrugated cardboard box to which a reinforcing member has been attached.

FIG. 2 is a perspective view illustrating the corrugated cardboard box to which the reinforcing member has been attached with the corrugated cardboard box assembled in a box shape.

FIG. 3 is a diagram illustrating corrugated cardboard used for the corrugated cardboard box.

FIG. 4 is a developed view illustrating a modification of the corrugated cardboard box to which the reinforcing member has been attached.

FIG. 5 is a diagram illustrating examples and comparative examples of the packing box.

DESCRIPTION OF EMBODIMENTS

A packing box 1 according to an embodiment will be described below with reference to the attached drawings. In the following description, the height direction is the vertical direction when the packing box 1 is assembled in a substantially rectangular parallelepiped shape and placed in a normal orientation. The lateral direction is the horizontal direction when the packing box 1 is assembled in a box shape and placed in a normal orientation. It should be noted that numerical values indicating the number, the dimensions, and the like of components are only examples unless otherwise specified and do not limit the following embodiments.
As illustrated in FIGS. 1 and 2 , the packing box 1 includes a corrugated cardboard box 3 and a reinforcing member 5.
The corrugated cardboard box 3 is an A-type corrugated cardboard box and includes single-corrugated cardboard. The type of corrugated cardboard constituting the corrugated cardboard box 3 is not particularly limited but is C-flute in the embodiment.
The corrugated cardboard box 3 includes two first side wall portions 7, two second side wall portions 9, four first flaps 11, four second flaps 13, and a sticking tab 15.
The first side wall portions 7 and the second side wall portions 9 constitute the side walls of the corrugated cardboard box 3 with the corrugated cardboard box 3 assembled in a box shape. The first side wall portions 7 and the second side wall portions 9 are alternately continuous with each other in the lateral direction.
The first flaps 11 and the second flaps 13 constitute the top wall and the bottom wall of the corrugated cardboard box 3 with the corrugated cardboard box 3 assembled in a box shape. The first flaps 11 are continuous with the first side wall portion 7 in the height direction. An end portion of the first flap 11 opposite to the first side wall portion 7 is referred to as a first flap end portion 17. The second flaps 13 are continuous with the second side wall portion 9 in the height direction. An end portion of the second flap 13 opposite to the second side wall portion 9 is referred to as a second flap end portion 19.
The sticking tab 15 is continuous with the first side wall portion 7 in the lateral direction and is bonded onto the inner surface of the second side wall portion 9 via an adhesive. It should be noted that the second side wall portion 9 attached to the sticking tab 15 is indicated by a dot-dot-dash line in FIGS. 1 and 4 .
A vertical ruled line 21 is formed between the first side wall portion 7 and the second side wall portion 9 and between the first side wall portion 7 and the sticking tab 15. In addition, a lateral ruled line 23 is formed between the first side wall portion 7 and the first flap 11 and between the second side wall portion 9 and the second flap 13.
The corrugated cardboard box 3 is assembled in a box shape (see FIG. 2 ) by being folded along the vertical ruled lines 21 and the lateral ruled lines 23. When the corrugated cardboard box 3 is assembled in a box shape, a vertical ridge line 25 is formed between the first side wall portion 7 and the second side wall portion 9, and a lateral ridge line 27 is formed between the first side wall portion 7 and the first flap 11 and between the second side wall portion 9 and the second flap 13.
The portions that become the vertical ridge lines 25 when the corrugated cardboard box 3 is assembled in a box shape are referred to as ridge line portions 29. The corrugated cardboard box 3 has four ridge line portions 29. Three of the four ridge line portions 29 correspond to the boundary portions between the first side wall portions 7 and the second side wall portions 9 that are continuous with each other in the lateral direction via the vertical ruled lines 21, and one of the four ridge line portions 29 corresponds to the boundary portion between the first side wall portion 7 and the second side wall portion 9 that are continuous with each other in the lateral direction via the sticking tab 15.
As illustrated in FIG. 3 , the first side wall portion 7 includes a first outer liner 31, a first inner liner 33, and a first inner core 35. The first inner core 35 is formed in a wave shape and provided between the first outer liner 31 and the first inner liner 33. Similarly, the second side wall portion 9 includes a second outer liner 37, a second inner liner 39, and a second inner core 41. The second inner core 41 is formed in a wave shape and provided between the second outer liner 37 and the second inner liner 39.
It should be noted that the sequential location of a wave from the ridge line portion 29 of a plurality of waves of the first inner core 35 is denoted by a corresponding subscript, such as in the case of “P₁” for a first inner core first wave P₁. For example, a first inner core third wave P₃is the third wave from the ridge line portion 29 of the plurality of waves of the first inner core 35. Similarly, the sequential location of a wave from the ridge line portion 29 of a plurality of waves of the second inner core 41 is denoted by a corresponding subscript, such as in the case of “Q₁” for a second inner core first wave Q₁. For example, a second inner core fourth wave Q₄is the fourth wave from the ridge line portion 29 of the plurality of waves of the second inner core 41. It should be noted that the ridge line portion 29 coincides with the peak of a wave of the inner core in FIG. 3 , but even when, for example, the ridge line portion 29 deviates from the peak of the wave, that is, when the ridge line portion 29 is present at a predetermined position between this peak and the peak of the next wave, the number of waves may be counted in the same manner.
In contrast to the embodiment, when the packing box 1 includes only the corrugated cardboard box 3, that is, when the reinforcing member 5 is not attached to the corrugated cardboard box 3, if, for example, a plurality of packing boxes 1 are bundled and stacked on a pallet, the vertical ridge line 25 is susceptible to being crushed, that is, a ridge line crush may occur due to stretch film wrapped around the plurality of packing boxes 1 applying a lateral load to the vertical ridge line 25. In addition, since the packing box 1 stacked at the bottom is subjected to a load from above, the entire packing box 1 may be crushed in the up-down direction; that is, a pressure crush may occur.
More specifically, in a ridge line crush, portions of the first side wall portion 7 and the second side wall portion 9 close to the vertical ridge line 25 may be crushed. The first side wall portion 7 and the second side wall portion 9 are likely to be crushed at positions of specific waves at sequential location from the ridge line portion 29 of the plurality of waves of the first inner core 35 and the second inner core 41. The positions of waves at which the first side wall portion 7 and the second side wall portion 9 are likely to be crushed depend on the type of the corrugated cardboard constituting the corrugated cardboard box 3, and these positions can be determined in advance through experiments. When the corrugated cardboard constituting the corrugated cardboard box 3 is C-flute, it is assumed that crushing is likely to occur in, for example, the first inner core third wave P₃and a first inner core eighth wave P₈in the first side wall portion 7 and in, for example, a second inner core third wave Q₃and a second inner core eighth wave Q₈in the second side wall portion 9.
In the packing box 1 according to the embodiment, the reinforcing member 5 is attached to the packing box 1 to prevent a ridge line crush and a pressure crush as described above from occurring. In the embodiment, the reinforcing member 5 is made of paper and is formed in a band shape, that is, a rectangle, but the shape of the reinforcing member 5 is not particularly limited and may be, for example, a rounded rectangle, an ellipse, or the like.
The reinforcing member 5 is attached to the corrugated cardboard box 3 along the ridge line portion 29. That is, the reinforcing member 5 is attached to the corrugated cardboard box 3 to cover the ridge line portion 29. It should be noted that, for example, a woodworking adhesive can be used as an adhesive for attaching the reinforcing member 5 to the corrugated cardboard box 3.
The basis weight of the reinforcing member 5 is 110 g/m²or more and may be 270 g/m²or more. When the basis weight of the reinforcing member 5 is 110 g/m²or more, the strength against a ridge line crush of the packing box 1 can be improved. When the basis weight of the reinforcing member 5 is 270 g/m²or more, the strength against a ridge line crush of the packing box 1 can be further improved, and the strength against a pressure crush of the packing box 1 can be improved. On the other hand, the basis weight of the reinforcing member 5 may be 400 g/m²or less. When the basis weight of the reinforcing member 5 is 400 g/m²or less, it is possible to suppress the bendability of the first side wall portion 7 and the second side wall portion 9 in the ridge line portion 29 to which the reinforcing member 5 has been attached from degrading.
The material of the reinforcing member 5 need only be paper, such as coated paper or cardboard, and may be coated paper. When the material of the reinforcing member 5 is coated paper, the strength against a ridge line crush and the strength against a pressure crush of the packing box 1 can be further improved. The material of the reinforcing member 5 may be glossy coated paper rather than matt coated paper to further improve the strength against a ridge line crush of the packing box 1.
The width, that is, the dimension in the lateral direction, of the reinforcing member 5 is not particularly limited but may be a first width W (see FIG. 3 ). Here, the first width W is the distance from a first inner core (m+1)th wave P_m+1to a second inner core (n+1)th wave Q_n+1if the portions farthest from the ridge line portion 29 of the portions of the first side wall portion 7 and the second side wall portion 9 susceptible to being crushed are the first inner core m-th wave P_mand the second inner core n-th wave Q_nwhen a lateral load is applied to the vertical ridge line 25 with the reinforcing member 5 not attached to the corrugated cardboard box 3. It should be noted that m and n are integers of 1 or more. In the embodiment, when a lateral load is applied to the vertical ridge line 25 with the reinforcing member 5 not attached to the corrugated cardboard box 3, since the portion farthest from the ridge line portion 29 of the portions of the first side wall portion 7 and the second side wall portion 9 susceptible to being crushed are the first inner core eighth wave P₈and the second inner core eighth wave Q₈, the first width W is the distance from a first inner core ninth wave P₉to a second inner core ninth wave Q₉. This first width W is, for example, 80 mm.
When the width of the reinforcing member 5 is equal to or more than the first width W, the reinforcing member 5 can cover and reinforce the portions of the first side wall portion 7 and the second side wall portion 9 that are likely to be crushed. On the other hand, there are no significant differences in the strength against a ridge line crush or in the strength against a pressure crush of the packing box 1 between the reinforcing member 5 having the first width W and the reinforcing member 5 that is wider than the first width W. Accordingly, the first width W is sufficient for the reinforcing member 5 to cover portions of the first side wall portion 7 and the second side wall portion 9 that are likely to be crushed. However, when the reinforcing member 5 is attached to the inner surface of the corrugated cardboard box 3, the larger the width of the reinforcing member 5, the greater the strength against a pressure crush of the packing box 1.
As illustrated in FIG. 4 , the reinforcing member 5 may be attached to a portion from the first flap 11 and the second flap 13 located on one side of the ridge line portion 29 in the height direction to the first flap 11 and the second flap 13 located on the other side of the ridge line portion 29 in the height direction and pass through the ridge line portion 29. A cut 43 in the height direction is formed in a portion of the reinforcing member 5 that has been attached to the first flap 11 and the second flap 13 such that the first flap 11 and the second flap 13 are each independently movable. It should be noted that the state as illustrated in FIG. 4 in which the reinforcing member 5 is attached to the portion from the ridge line portion 29 to the first flap 11 and the second flap 13 is also referred to below as “flap attached”, and the state as illustrated in FIG. 1 in which the reinforcing member 5 is attached to only the ridge line portion 29 and not to the first flap 11 and the second flap 13 is also referred to below as “flap not attached”.
In the flap attached state, the strength against a ridge line crush of the packing box 1 and the strength against a pressure crush of the packing box 1 can be further improved compared with the flap not attached state. This is because attaching the reinforcing member 5 to the first flap 11 and the second flap 13 in addition to the ridge line portion 29 reinforces not only the vertical ridge line 25 of the packing box 1 but also the corners 45 (see FIG. 2 ) and thereby improves the strength of the vertical ridge line 25.
It should be noted that the reinforcing member 5 need not be attached to a portion from the first flap end portion 17 and the second flap end portion 19 located on one side of the ridge line portion 29 in the height direction to the first flap end portion 17 and the second flap end portion 19 located on the other side of the ridge line portion 29 in the height direction. That is, the reinforcing member 5 need only be attached to a portion from a position between the first flap end portion 17 and the second flap end portion 19 located on one side of the ridge line portion 29 in the height direction to a position between the first flap end portion 17 and the second flap end portion 19 located on the other side of the ridge line portion 29 in the height direction.
The reinforcing member 5 may be attached to the outer surface of the corrugated cardboard box 3, that is, the first outer liner 31 and the second outer liner 37, or may be attached to the inner surface of the corrugated cardboard box 3, that is, the first inner liner 33 and the second inner liner 39. The strength against a ridge line crush of the packing box 1 does not differ notably between the state in which the reinforcing member 5 is attached to the outer surface of the corrugated cardboard box 3 and the state in which the reinforcing member 5 is attached to the inner surface of the corrugated cardboard box 3. However, the strength of the packing box 1 against a pressure crush in the state in which the reinforcing member 5 is attached to the outer surface of the corrugated cardboard box 3 is higher than that in the state in which the reinforcing member 5 is attached to the inner surface of the corrugated cardboard box 3. On the other hand, in consideration of appearance, the reinforcing member 5 may be attached to the inner surface of the corrugated cardboard box 3 to make the reinforcing member 5 less noticeable.
The reinforcing member 5 may be attached to one of the four ridge line portions 29 or may be attached to two or more of the four ridge line portions 29. As a measure against a ridge line crush, of the four ridge line portions 29, the reinforcing member 5 need be attached to only the ridge line portions 29 that become the vertical ridge lines 25 to which a lateral load is applied by stretch film. In addition, the reinforcing member 5 need not cover the entire ridge line portion 29, that is, from one end to the other end of the ridge line portion 29, but may cover a portion of the ridge line portion 29 of, for example, three-quarters or more of the entire length of the ridge line portion 29. In addition, the reinforcing member 5 may be attached to the corrugated cardboard box 3 before the corrugated cardboard box 3 is assembled in a box shape or may be attached to the corrugated cardboard box 3 after the corrugated cardboard box 3 is assembled in a box shape.
As described above, the packing box 1 according to the embodiment includes the corrugated cardboard box 3 and the reinforcing member 5 attached to the corrugated cardboard box 3 along the ridge line portion 29 of the corrugated cardboard box 3. The reinforcing member 5 is made of paper having a basis weight of 110 g/m²or more. This structure can suppress a ridge line crush from occurring in the packing box 1.
It should be noted that, when the corrugated cardboard constituting the corrugated cardboard box 3 is C-flute, attaching the reinforcing member 5 along the ridge line portion 29 of the corrugated cardboard box 3 can result in the same strength against a ridge line crush as that of a corrugated cardboard box made of CB-flute corrugated cardboard. Accordingly, a corrugated cardboard box made of CB-flute corrugated cardboard can be replaced with the packing box 1 in which the reinforcing member 5 has been attached to the corrugated cardboard box 3 made of C-flute corrugated cardboard. As a result, the cost of the corrugated cardboard box 3 can be reduced. In addition, since the weight of the corrugated cardboard constituting the corrugated cardboard box 3 is reduced, the environmental load can be reduced.

Examples

First, reinforcing members having the specifications illustrated in FIG. 5 are attached to a corrugated cardboard box having the following specifications by using a woodworking adhesive. The reinforcing members are attached to the corrugated cardboard box along two ridge line portions other than the ridge line portion corresponding to the boundary portion between the first side wall portion and the second side wall portion that are continuous with each other in the lateral direction with the sticking tab therebetween and the ridge line portion located diagonally with respect to the ridge line portion of the four ridge line portions. The packing box is assembled in a box shape after the woodworking adhesive sufficiently dries.

Specifications of the Corrugated Cardboard Box

- Type: Type A (Type 0201)
- Size: Width 200 mm, Length 200 mm, Height 100 mm
- Corrugated cardboard: C-flute

After the packing box is assembled, a lateral load is applied to the vertical ridge lines to which the reinforcing members have been attached by using a compression testing machine, and the load at which a ridge line crush occurs is measured. In addition, a load in the up-down direction is applied to the packing box by using the compression testing machine, and the load at which a pressure crush occurs is measured.
It should be noted that the strength against a ridge line crush of the packing box is evaluated on the following five scales indicating the ratio, expressed as a percentage, of the load at which a ridge line crush occurs in the packing box to which the reinforcing member has been attached to the load at which a ridge line crush occurs in the packing box according to comparative example 1, that is, the packing box to which the reinforcing member has not been attached.

- A: 300% or more
- B: 220% or more and less than 300%
- C: 170% or more and less than 220%
- D: 150% or more and less than 170%
- E: Less than 150%

It should be noted that, when the strength against a ridge line crush of the packing box is one of A to D, that is, when the load at which a ridge line crush occurs is 150% or more of the load for the packing box to which the reinforcing member has not been attached, a ridge line crush can be prevented from occurring due to a load applied by stretch film.
In addition, the strength against a pressure crush of the packing box is evaluated on the following three scales indicating the ratio, expressed as a percentage, of the load at which a pressure crush occurs in the packing box to which the reinforcing member has been attached to the load at which a pressure crush occurs in the packing box according to comparative example 1, that is, the packing box to which the reinforcing member has not been attached.

- A: 130% or more
- B: 110% or more and less than 130%
- C: Less than 110%

As illustrated in FIG. 5 , when examples 1 to 11 in which the reinforcing member having a basis weight of 110 g/m²or more has been attached are compared with comparative example 1 in which the reinforcing member has not been attached and with comparative example 2 in which the reinforcing member having a basis weight of 31 g/m²has been attached, the strength against a ridge line crush of the packing box in examples 1 to 11 has been improved.
When examples 2 to 5 in which the reinforcing member having a basis weight of 270 g/m²or more has been attached are compared with example 1 in which the reinforcing member having a basis weight of 110 g/m²has been attached, the strength against a ridge line crush of the packing box and the strength against a pressure crush of the packing box in examples 2 to 5 have both been improved.
When example 2 in which the reinforcing member has been attached to the outer surface of the corrugated cardboard box is compared with example 6 in which the reinforcing member has been attached to the inner surface of the corrugated cardboard box, the strength against a pressure crush of the packing box in example 2 has been further improved. Likewise, in a comparison between example 4 and example 7, a similar tendency is observed.
When example 4 in which the reinforcing member made of glossy coated paper has been attached is compared with example 5 in which the reinforcing member made of cardboard has been attached, the basis weight in example 4 is lower than that in in example 5, but the strength against a ridge line crush of the packing box in example 4 has been further improved.
When example 2 for which “flap attached” is specified is compared with example 8 for which “flap not attached” is specified, the strength against a ridge line crush of the packing box and the strength against a pressure crush of the packing box in example 2 have both been further improved.
Regarding the examples in which the reinforcing member has been attached to the outer surface of the corrugated cardboard box, when example 8 in which the reinforcing member with a width of 80 mm, that is, the reinforcing member with the first width, has been attached is compared with example 9 in which the reinforcing member with a width of 160 mm has been attached, the strength against a ridge line crush of the packing box and the strength against a pressure crush of the packing box in example 8 and example 9 are the same. On the other hand, regarding the examples in which the reinforcing member has been attached to the inner surface of the corrugated cardboard box, when example 10 in which the reinforcing member with a width of 80 mm, that is, the reinforcing member with the first width, has been attached is compared with example 11 in which the reinforcing member with a width of 160 mm has been attached, the strength against a ridge line crush of the packing box in example 10 and example 11 is the same, but the strength against a pressure crush of the packing box in example 10 is higher.

Other Modifications

It will be appreciated that the present disclosure is not limited to the embodiments described above and that various structures can be adopted without departing from the spirit of the disclosure. For example, the embodiments described above can be modified as described below in addition to as described above. In addition, the embodiments and the modifications may be combined with each other.
The type of the corrugated cardboard box 3 is not limited to type A and may be another type, such as type B, type C, or type N. The type of corrugated cardboard constituting the corrugated cardboard box 3 is not limited to C-flute and may be A-flute, B-flute, W-flute, or the like.

ADDITIONAL DESCRIPTION

A packing box will be additionally described below.
A packing box includes a corrugated cardboard box that includes first side wall portions and second side wall portions and in which a vertical ridge line is formed between each of the first side wall portions and each of the second side wall portions with the corrugated cardboard box assembled in a box shape; and a reinforcing member that is made of paper having a basis weight of 110 g/m²or more and is attached to the corrugated cardboard box along a ridge line portion that becomes the vertical ridge line with the corrugated cardboard box assembled in a box shape.
This structure can improve the strength against a ridge line crush of the packing box.
In this case, the basis weight of the reinforcing member may be 270 g/m²or more.
This structure can further improve the strength against a ridge line crush of the packing box and improve the strength against a pressure crush of the packing box.
In this case, the corrugated cardboard box includes first flaps, of the first side wall portions, continuous with each in a height direction and second flaps, of the second side wall portions, continuous with each in the height direction, and the reinforcing member may be attached to a portion from one of the first flaps and one of the second flaps located on one side of the ridge line portion in the height direction to the other of the first flaps and the other of the second flaps located on the other side of the ridge line portion in the height direction and pass through the ridge line portion.
This structure can further improve the strength against a ridge line crush of the packing box and the strength against a pressure crush of the packing box.
In this case, the reinforcing member may be made of coated paper.
This structure can further improve the strength against a ridge line crush of the packing box.
In this case, the first side wall portion may include a first inner core in which a plurality of waves are formed, the second side wall portion may include a second inner core in which a plurality of waves are formed, a portion farthest from the ridge line portion of portions of the first side wall portion susceptible to being crushed when a lateral load is applied to the vertical ridge line with the reinforcing member not attached to the corrugated cardboard box may be located at a position of an m-th wave from the ridge line portion of the plurality of waves formed in the first inner core, a portion farthest from the ridge line portion of portions of the second side wall portion susceptible to being crushed when a lateral load is applied to the vertical ridge line with the reinforcing member not attached to the corrugated cardboard box may be located at a position of an n-th wave from the ridge line portion of the plurality of waves formed in the second inner core, and the reinforcing member may have a width corresponding to a distance from an (m+1)th wave from the ridge line portion of the plurality of waves formed in the first inner core to an (n+1)th wave from the ridge line portion of the plurality of waves formed in the second inner core.
This structure can reinforce the portion in which a ridge line crush is likely to occur by using a reinforcing member whose width is as small as possible.
In this case, the corrugated cardboard box may be made of C-flute corrugated cardboard.
This structure can realize the same strength against a ridge line crush as the corrugated cardboard box made of CB-flute corrugated cardboard.

Claims

What is claimed is:

1. A packing box comprising:

a corrugated cardboard box that includes a first side wall portion and a second side wall portion and in which a vertical ridge line is formed between the first side wall portion and the second side wall portion with the corrugated cardboard box assembled in a box shape; and

a reinforcing member that is made of paper having a basis weight of 110 g/m²or more and is attached to the corrugated cardboard box along a ridge line portion that becomes the vertical ridge line with the corrugated cardboard box assembled in a box shape.

2. The packing box according to claim 1, wherein

the reinforcing member has a basis weight of 270 g/m²or more.

3. The packing box according to claim 1, wherein

the corrugated cardboard box includes first flaps continuous with the first side wall portion in a height direction and second flaps continuous with the second side wall portion in the height direction, and

the reinforcing member is attached to a portion from one of the first flaps and one of the second flaps located on one side of the ridge line portion in the height direction to another of the first flaps and another of the second flaps located on another side of the ridge line portion in the height direction and passes through the ridge line portion.

4. The packing box according to claim 1, wherein

the reinforcing member is made of coated paper.

5. The packing box according to claim 1, wherein

the first side wall portion includes a first inner core in which a plurality of waves are formed,

the second side wall portion includes a second inner core in which a plurality of waves are formed,

a portion farthest from the ridge line portion of portions of the first side wall portion susceptible to being crushed when a lateral load is applied to the vertical ridge line with the reinforcing member not attached to the corrugated cardboard box is located at a position of an m-th wave from the ridge line portion of the plurality of waves formed in the first inner core,

a portion farthest from the ridge line portion of portions of the second side wall portion susceptible to being crushed when a lateral load is applied to the vertical ridge line with the reinforcing member not attached to the corrugated cardboard box is located at a position of an n-th wave from the ridge line portion of the plurality of waves formed in the second inner core, and

the reinforcing member has a width corresponding to a distance from an (m+1)th wave from the ridge line portion of the plurality of waves formed in the first inner core to an (n+1)th wave from the ridge line portion of the plurality of waves formed in the second inner core.

6. The packing box according to claim 1, wherein

the corrugated cardboard box is made of C-flute corrugated cardboard.