JP6801807B1 - Cardboard material and cardboard boxes using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a box in good condition with respect to a corrugated cardboard material and a corrugated cardboard box. SOLUTION: In a bellows-folded corrugated cardboard material 1, a rectangular sheet 2 is folded back to a second-direction MD at each of folds F in which a rectangular sheet 2 extends linearly along a first-direction CD in continuous cardboard. Sheets 2 are stacked along a three-way TD, and are double-sided cardboard with double flutes. This sheet 2 was measured in accordance with JIS P8131 under normal conditions of pretreatment for 24 hours or more under temperature and humidity conditions of temperature 23 [° C.] and humidity 50 [%] in accordance with JIS Z0203. The burst strength of the portion including the eyes is 520 [kPa] or more and 2500 [kPa] or less. [Selection diagram] Fig. 1

Description

The present invention relates to a bellows-folded corrugated cardboard material and a corrugated cardboard box using the same.

Corrugated cardboard material with bellows fold (also called "fan fold") is known as a material for box making. The corrugated cardboard material is provided with creases between continuous rectangular sheets, and the sheets are alternately folded back at the folds. In such a bellows-folded cardboard material, continuous sheets are stacked one above the other and folded into a rectangular parallelepiped packaging.

The above cardboard materials are box-making systems (“automatic packaging system”, “three-sided variable system”, “three-sided automatic packaging”, and “on-demand packaging” that manufacture boxes of the optimum size according to the size of the packaging target. It is also used as a packaging material. In this box-making system, various steps illustrated below are carried out (see Patent Document 1 below).
・ Feed process: Process of feeding out bellows-folded cardboard material ・ Cutting process: Process of cutting out flat cardboard material fed in the feed process ・ Folding process: Process of assembling a box from the cardboard material cut out in the cutting process ・ Printing process : Process of printing on flat or assembled cardboard material ・ Packing process: Process of storing the contents in the assembled box

Special Table 2013-513869

However, when a bellows-folded cardboard material is used as a material for a box-making system, the state of the manufactured box may be poor depending on the properties of the sheet used for the cardboard material.
This case was devised in view of the above issues, and one of the purposes is to manufacture a box in good condition. Not limited to this purpose, it is also possible that the actions and effects derived from each configuration shown in the “mode for carrying out the invention” described later and which cannot be obtained by the conventional technique are exhibited. It can be positioned as another purpose.

The corrugated cardboard material disclosed here is a second corrugated cardboard material orthogonal to the first direction on a plane along the fold at each of the folds in which a rectangular sheet extends linearly along the first direction in continuous cardboard. A bellows-folded corrugated cardboard material that is folded back in a direction and the sheets are stacked along a third direction orthogonal to both the first direction and the second direction.
The corrugated cardboard material was measured in a normal state in which the properties of the sheet were pretreated for 24 hours or more under temperature and humidity conditions of a temperature of 23 [° C.] and a humidity of 50 [%] in accordance with JIS Z0203. It has a predetermined configuration which is a parameter of.
The predetermined configuration includes at least one of the configurations a to e shown below.

Configuration a includes the following configurations 1 and 2.
The configuration 1 includes that the thickness dimension measured in accordance with the corrugated board industry standard T0004: 2000 is 2.0 [mm] or more and 9.6 [mm] or less.
Configuration 2 includes that the planar compressive strength measured in accordance with JIS Z0403-1 is 50 [kPa] or more and 250 [kPa] or less.

Configuration b includes the above configuration 2 and the following configuration 3.
The configuration 3 includes a step-by-step rate of 1.2 [times] or more and 1.7 [times] or less.

In configuration c, the cores intersect and are adjacent to a virtual auxiliary line extending in the second direction at the center of the front liner and the back liner when viewed from the first direction. The ratio of the difference between the two acute angles formed by the auxiliary line and the auxiliary line divided by the sum of the two acute angles is 0.30 or less.

Configuration d includes that the burst strength measured in accordance with JIS P8131 is 500 [kPa] or more.
The configuration d'includes that, in a single flute double-sided corrugated cardboard, the burst strength at a portion including a crease measured in accordance with JIS P8131 is 500 [kPa] or more.
In the configuration d ″, in the double-sided corrugated cardboard of the double flute, the burst strength of the portion not including the crease measured in accordance with JIS P8131 is 500 [kPa] or more, and is measured in accordance with JIS P8131. It includes that the burst strength of the portion including the fold is 520 [kPa] or more.

The configuration e includes that the average value of the adhesive force measured on the single facer side and the glue machine side in accordance with JIS Z0402 is 140 [N] or more.

According to this case, a box in good condition can be manufactured.

It is a perspective view which shows the corrugated cardboard material of a bellows fold. It is a schematic diagram which shows an example of the step | step in the sheet used for the corrugated cardboard material of bellows folding. It is a schematic diagram which shows the evaluation box for evaluating the easiness of tearing from the top view. It is a schematic diagram which shows the evaluation box for evaluation of easiness of tearing from the side view.

Hereinafter, a corrugated cardboard material and a corrugated cardboard box as embodiments will be described.
The corrugated cardboard material of the present embodiment is a bellows-folded box-making material in which a rectangular sheet is folded in continuous corrugated cardboard. As this corrugated cardboard material, double-sided corrugated cardboard having liners on both sides with respect to the core is used.
The above-mentioned double-sided cardboard includes single-flute cardboard composed of three base papers (materials) corresponding to one core and two liners, as well as so-called "double-sided cardboard" and "double-sided cardboard". Also included are multi-flute cardboard composed of three or more cores (including one or more middle liners) and five or more base papers corresponding to each of the two liners.

When the cardboard material is made into a box, it becomes a cardboard box. Specifically, the corrugated cardboard material used as the box-making material of the box-making system has a feed process in which the sheets are sent out in sequence, a cutting process in which the sent-out sheets are cut out in a box development pattern, and folding into a box shape. It is made into a cardboard box through various processes such as a folding process in which it is erected. The box-making system for assembling the cardboard box is not particularly limited, but for example, "Carton Wrap 1000 made by CMC" and "CVP-500 made by Neopost" which are fully automatic systems (fully automatic machines) of the automatic packaging system. , "TXP-600 made by OS Machinery", "EM7 made by Pack Size" of semi-automatic system (semi-automatic machine), "Compack made by Panotec", "PAQTEC C-200 made by HOMAG", "HOMAG" A company-made PAQTEC C-250 "can be used.

In the present embodiment, it is assumed that the corrugated cardboard material is placed on a horizontal plane by giving an example in which the following directions I and II correspond as shown in Table 1 below.
-Direction I: Direction in the corrugated cardboard placed on the horizontal plane-Direction II: Direction in the semi-finished product in the middle of manufacturing the cardboard material

The vertical direction (first direction, indicated by "CD" in the figure) and the horizontal direction (second direction, indicated by "MD" in the figure) are horizontal directions and along the sheet (crease). The direction in which the plane extends. These vertical and horizontal directions are orthogonal to each other. The height direction (third direction, indicated by "TD" in the figure) is a direction along the vertical direction and is orthogonal to both the vertical direction and the horizontal direction. This height direction corresponds to the direction in which the sheets are overlapped.

The MD (Machine Direction) direction is also referred to as a "flow direction", and is a direction in which the corrugated cardboard material manufacturing process progresses from upstream to downstream. The CD (Cross Direction) direction is a direction orthogonal to the MD direction in a plane along the MD direction. The TD (Transverse Direction) direction is a direction orthogonal to both the MD direction and the CD direction.
In addition, unless otherwise specified, the expression "numerical value X to numerical value Y" in this embodiment means a range of numerical value X or more and numerical value Y or less.

[I. One Embodiment]
In one embodiment below, the configuration of the corrugated cardboard material will be described in items [1] and [2]. Item [1] describes a structure in which the corrugated cardboard material is folded (hereinafter referred to as “folded structure”). Item [2] describes parameters related to the properties of the sheet (corrugated cardboard sheet) used for the corrugated cardboard material.
Then, the actions and effects of the configurations of items [1] and [2] will be described in item [3].

[1. Folding structure]
As shown in FIG. 1, the corrugated cardboard material 1 is a box-making material having a rectangular parallelepiped shape.
In the corrugated cardboard material 1, the continuous rectangular sheet 2 (partially marked in FIG. 1) is folded back at the crease F (only partly coded in FIG. 1), and the folded sheet 2 is folded. They are stacked in the height direction.
In the corrugated cardboard material 1 folded in this way, a plurality of folds F extend linearly along the vertical direction on a pair of side surfaces along both the vertical direction and the height direction.

Here, the folding structure of the corrugated cardboard material 1 will be described by focusing on three consecutive sheets 2 (indicated by a two-dot chain line in FIG. 1).
1st sheet 21: Sheet 2 continuous on one side of the 2nd sheet 22
Second sheet 22: Sheet 2 continuous with both the first sheet 21 and the third sheet 23
-Third sheet 23: Sheet 2 continuous with the other side of the second sheet 22

The first fold F1 is provided between the first sheet 21 and the second sheet 22, and the sheets 21 and 22 are continuous via the first fold F1. A second fold F2 is provided between the second sheet 22 and the third sheet 23, and the sheets 22 and 23 are continuous via the second fold F2.
The first fold F1 is a fold F in which the second sheet 22 is folded back toward one side (right side in FIG. 1) with respect to the first sheet 21, and the other side in the corrugated cardboard material 1 (right side in FIG. 1). It is arranged on the left side in FIG. The second fold F2 is a fold F in which the third sheet 23 is folded back toward the other side in the lateral direction (left in FIG. 1) with respect to the second sheet 22, and the second fold F2 is one in the lateral direction (one in the corrugated cardboard material 1). It is arranged on the right side in FIG.

In the first sheet 21, the corrugated cardboard step 10 (in FIG. 1, only the front edge is marked) extends to the _first edge E ₁ extending in the lateral direction (the direction intersecting the fold F). Waves) are exposed. Similarly, on the second sheet 22, the cardboard is provided on the second edge E ₂ extending in the lateral direction (the direction intersecting the crease F) (in FIG. 1, only the front edge is marked). The step 10 is exposed.
In the sheet pair 20 composed of the first sheet 21 and the second sheet 22, the first end edge E ₁ and the second end edge E ₂ are arranged adjacent to each other in the height direction.

According to the corrugated cardboard material 1 having the above-mentioned folding structure, even a material that is difficult to wind in a roll shape can be folded into a rectangular parallelepiped shape. That is, the corrugated cardboard sheet 2 having a higher strength than the material that can be wound in a roll shape can be made into a compact packaging. The corrugated cardboard material 1 in which the sheet 2 whose strength is ensured is folded in this way is suitable for use as a packaging material for a box-making system for manufacturing a box in which strength is required.

In addition, the fold F is provided along the corrugated cardboard step 10. In other words, the corrugated cardboard material 1 having a step 10 perpendicular to the MD direction is manufactured.
The corrugated cardboard material 1 is preferably wrapped (wrapped) with a packaging film in order to prevent stains and collapse of the load.

[2. Parameters]
Hereinafter, the parameters of the corrugated cardboard material 1 will be described.
First, basic parameters such as the size and the number of stages of the corrugated cardboard material 1 will be described. After that, the parameters related to the sheet 2 of the corrugated cardboard material 1 will be described in detail.

[2-1. Basic parameters]
The size of the corrugated cardboard material 1 is determined from the following dimensions L1 to L3.
-Vertical dimension L1: Vertical dimension (first dimension)
-Horizontal dimension L2: Horizontal dimension (second dimension)
-Height dimension L3: Dimension in the height direction (third dimension)
The smaller the dimensions L1 to L3, the greater the restrictions on the size and shape of the box to be manufactured, and the larger the size, the lower the workability such as transportation and delivery. From these viewpoints, the dimensions L1 to L3 are preferably in the range shown in Table 2 below.

In addition, if the number of folds F in the corrugated cardboard material 1 is N [sheets], the number of sheets 2 is N + 1 [sheets]. In this case, the N + 1 [stage] sheets 2 are overlapped on the cardboard material 1.
For example, as the number of stages of the corrugated cardboard material 1, for example, various stages of 10 to 1000 [stages] can be mentioned. For the corrugated cardboard material to which the parameters related to folding, which will be described in detail later, are measured, it is preferable to measure the parameters at each of all the stages for the measurement target having less than a predetermined number of stages (for example, 100 [stages]). On the other hand, for a measurement target having a predetermined number of stages (for example, 100 [stages]) or more, the parameters may be measured partially (for example, a portion divided into parts or a set area).

An arbitrary basis weight can be set for the sheet 2 used for the corrugated cardboard material 1. The range of the basis weight adopted for the sheet 2 includes a range of 50 to 1500 [g / m ² ], preferably a range of 100 to 1000 [g / m ² ], and more preferably 200 to 200. The range of 800 [g / m ² ] is mentioned, and more preferably the range of 200 to 600 [g / m ² ] is mentioned.
The weight of the corrugated cardboard material 1 is calculated by multiplying the above basis weight by the vertical dimension L1 and the horizontal dimension L2 and the number of steps N + 1 of the sheet 2.

[2-2. Parameters related to sheet properties]
The corrugated cardboard material 1 of the present embodiment has a configuration relating to the properties of the sheet 2 from the viewpoint of enabling a good box to be manufactured when used as a material for a box making system. Specifically, it has a predetermined configuration regarding the properties of the sheet 2 based on at least one of the viewpoints I to V listed below.
-Viewpoint I: Ensuring box-making property-Viewpoint II: Suppressing breakage of bent parts when assembling into a box-Viewpoint III: Ensuring suitability when printing is performed-Viewpoint IV: Suppressing tearing (damage) of the assembled box ・ Viewpoint V: Suppressing the peeling of the liner

The above viewpoints I to V are viewpoints for solving the following problems I to V in which common ordinal numbers I to V are described.
-Problem I: Insufficient box-making property-Problem II: The bent part is easily broken when assembling into a box-Problem III: Insufficient suitability when printed・ Problem IV: Easy to tear the assembled box ・ Problem V: Easy to peel off the liner

The predetermined configurations corresponding to the above viewpoints I to V and tasks I to V include at least one of the following configurations a to e.
-Structure a: The following configurations 1 and 2
＞ Configuration 1: Thickness dimension is within a predetermined dimensional range ＞ Configuration 2: Planar compressive strength is within a predetermined compressive strength range ・ Configuration b: The following configurations 2 and 3
> Configuration 2: Configuration 2 above
> Configuration 3: The step-by-step ratio is within a predetermined magnification range ・ Configuration c: The angle ratio is within a predetermined ratio range ・ Configuration d: The burst strength is within a predetermined burst strength range ・ Configuration d ′ : Folded in cardboard material 1 made of single flute double-sided cardboard
The burst strength of the part including the eye F is within the predetermined burst strength range. ・ Composition d ″: Lower in the corrugated cardboard material 1 composed of double-sided corrugated cardboard of double flute.
Satisfying the above configurations 4 and 5> Configuration 4: The burst strength of the portion not including the fold F is within the predetermined burst strength range> Configuration 5: The burst strength of the portion including the fold F is predetermined -Structure e: Adhesive strength must be within the specified force range

<Structure a>
As described above, the configuration a includes "configuration 1 in which the thickness dimension is in a predetermined dimensional range" and "configuration 2 in which the planar compressive strength is in a predetermined compressive strength range".
The "thickness dimension" of the configuration a is a parameter representing the thickness of the sheet 2 per sheet. The "planar compressive strength" of the configuration a is the strength when the sheet 2 is compressed in the thickness direction (height direction, TD direction), and is a parameter corresponding to the difficulty of crushing the sheet of the corrugated cardboard material 1.

The inventors of the present application have found that if the thickness dimension of the sheet 2 is within a predetermined dimensional range and the planar compressive strength is within a predetermined compressive strength range, the above-mentioned problems I and II tend to be suppressed. Got Conversely, it was found that the sheet 2 having a thickness dimension and a planar compressive strength outside the range of the configuration a tends to cause problems I and II.
That is, the sheet 2 is provided with the configuration a based on the above-mentioned viewpoints I and II.

If the thickness dimension exceeds the predetermined dimension range, it is presumed that when the sheet 2 is bent by the ruled line for box making, the liners 2a and 2b are not fully stretched and are broken, which causes the problem II. On the other hand, if the thickness dimension is less than the predetermined dimension range, it is presumed that the strength of the sheet 2 is insufficient and the sheet 2 is bent at a place other than the ruled line for box making, which causes the problem I. Even when the plane compressive strength is below the predetermined compressive strength range, it is presumed that the strength of the sheet 2 is insufficient and it is bent at a place other than the ruled line for box making, which causes problem I. To.
Further, if the planar compressive strength exceeds a predetermined compressive strength range, it is presumed that the ruled lines for box making are difficult to form, which causes the problem I.

The "predetermined dimensional range" of the configuration a is 2.0 [mm] or more and 9.6 [mm] or less, and 3.0 [mm] or more and 8.0 [mm] or less. It is preferable that it is 4.0 [mm] or more and 7.0 [mm] or less.
Further, the "predetermined compressive strength range" of the configuration a is preferably 50 [kPa] or more and 250 [kPa] or less, and 80 [kPa] or more and 220 [kPa] or less. It is more preferable that it is 110 [kPa] or more and 190 [kPa] or less.

<Structure b>
The configuration b includes the same "configuration 2 in which the planar compressive strength is in a predetermined compressive strength range" and the above-mentioned "configuration 3 in which the step ratio is in a predetermined magnification range" similar to the configuration a.
The "step ratio" of the configuration b is a parameter representing the magnification of the length dimension in the MD direction (horizontal direction) with respect to the liner of the core.

The inventors of the present application have found that if the planar compressive strength of the sheet 2 is within a predetermined compressive strength range and the step-by-step ratio is within a predetermined magnification range, the above-mentioned problem I tends to be suppressed. Obtained. Conversely, it was found that the sheet 2 having the plane compression strength and the step-by-step ratio outside the range of the configuration b tends to cause the problem I.
That is, the sheet 2 is provided with the configuration b based on the above-mentioned viewpoint I.

If the plane compressive strength is less than the predetermined compressive strength range, it is presumed that the problem I is caused by the insufficient strength of the sheet 2 as described above. On the other hand, if the planar compressive strength exceeds a predetermined compressive strength range, it is presumed that the ruled lines for box making are difficult to form, which causes problem I.
Similarly, if the step-by-step ratio is less than the above-mentioned predetermined magnification, it is presumed that the problem I is caused by the insufficient strength of the sheet 2. On the other hand, if the step-by-step ratio exceeds the above-mentioned predetermined magnification, it is presumed that the ruled line for box making is difficult to be formed, which causes the problem I.

The "predetermined compressive strength range" of the configuration b is 50 [kPa] or more and 250 [kPa] or less, and 80 [kPa] or more, similarly to the "predetermined compressive strength range" of the configuration a. It is preferably 220 [kPa] or less, and more preferably 110 [kPa] or more and 190 [kPa] or less.
The "predetermined magnification range" of configuration b is 1.2 [times] or more and 1.7 [times] or less, and 1.35 [times] or more and 1.6 [times] or less. It is preferable, and it is more preferable that it is 1.45 [times] or more and 1.55 [times] or less.

The magnification range of the step-by-step rate referred to here can be applied not only when the sheet 2 is a single flute but also when the sheet 2 is a double flute. Specifically, the stepping rate of any of the cores of the double flute is 1.2 [times] or more and 1.7 [times] or less, and 1.35 [times] or more and 1 It is preferably 6.6 [times] or less, and more preferably 1.45 [times] or more and 1.55 [times] or less. The step-by-step rate of the double flute referred to here is a step-by-step rate calculated for each stage (the stage corresponding to each flute of one and the other in the double flute).

<Structure c>
As described above, the configuration c includes "a configuration in which the angle ratio is within a predetermined ratio range".
The “angle ratio” of the configuration c is a parameter corresponding to the degree of inclination of the step 10 in the sheet 2 of the corrugated cardboard material 1.
Hereinafter, the angle ratio will be described with reference to FIG. 2, which shows an enlarged main part of the sheet 2. FIG. 2 illustrates a state in which the step 10 of the sheet 2 is slightly tilted.

The sheet 2 has a structure in which the liners 2a and 2b on the front and back surfaces and the core 2c are bonded to each other. The core 2c constitutes the step 10, and forms a corrugated structure between the liners 2a and 2b.
If the core 2c has an ideal shape, the cross section (that is, the step 10) along the lateral direction and the height direction has a sinusoidal shape. On the other hand, in the actual sheet 2, the step 10 formed by the core 2c may be tilted with respect to the ideal shape. The angle ratio expresses the degree of such inclination.

This angle ratio is a ratio calculated based on the angles θ1 and θ2 (intersection angles) at which the core 2c and the auxiliary line L intersect.
The auxiliary line L is a virtual line that is parallel to the liners 2a and 2b (that is, the lateral direction <MD direction>) and passes through the center of the liners 2a and 2b (that is, the center of the height direction <TD direction>). Is set as.
The angles θ1 and θ2 are acute angles among the intersection angles at the two adjacent points P1 and P2 at the points where the core 2c intersects the auxiliary line L.

The angle ratio is the ratio obtained by dividing the absolute value of the difference between the two angles θ1 and θ2 by the sum of the two angles θ1 and θ2. This angle ratio is represented by the following formula c.
Angle ratio = | θ1-θ2 | / (θ1 + θ2) ... Equation c
The angle ratio defined in this way is 0 (zero) in the case of the ideal step 10, and becomes a large value as the step 10 is deviated.

The inventors of the present application have found that if the angle ratio of the sheet 2 is within a predetermined ratio range, the above-mentioned problem III tends to be suppressed. Conversely, it was found that the sheet 2 having an angle ratio outside the range of the configuration c tends to cause the problem III.
That is, the sheet 2 is provided with the configuration c based on the above-mentioned viewpoint III.
If the angle ratio exceeds a predetermined ratio range, the heights of the steps 10 on the sheet 2 tend to be uneven, which is presumed to lead to Problem III.
The “predetermined ratio range” of the configuration c is 0.30 or less, preferably 0.15 or less, and more preferably 0.05 or less.

<Structure d>
As described above, the configuration d includes "a configuration in which the burst strength is within a predetermined burst strength range".
The “burst strength” of the configuration d is a parameter corresponding to the load capacity of the sheet 2 in the corrugated cardboard material 1.
The inventors of the present application have found that if the burst strength of the sheet 2 is within a predetermined burst strength range, the above-mentioned problem IV tends to be suppressed. Conversely, it was found that the sheet 2 having a burst strength outside the range of the configuration d tends to cause the problem IV.

That is, the sheet 2 is provided with the configuration d based on the above-mentioned viewpoint IV.
If the burst strength is less than the predetermined burst strength range, it is presumed that the problem IV is caused by the insufficient load capacity of the sheet 2.
The "predetermined burst strength range" of the configuration d is 500 [kPa] or more, preferably 1000 [kPa] or more, and more preferably 2000 [kPa] or more.

<Structure d'>
As described above, the configuration d'provides a corrugated cardboard material 1 made of double-sided corrugated cardboard with a single flute, "a configuration in which the burst strength at a portion including the fold F is within a predetermined burst strength range".
The "burst strength" of the configuration d'is the same as the "burst strength" described above in the configuration d, except that it is the burst strength of the portion including the crease F.
The inventors of the present application have stated that the above-mentioned problem IV tends to be suppressed if the burst strength of the portion of the sheet 2 of the single flute cardboard material 1 including the crease F is within a predetermined burst strength range. I got the knowledge. Conversely, it was found that the sheet 2 having the burst strength at the portion including the fold F outside the range of the configuration d'tends to cause the problem IV.

That is, the sheet 2 is provided with a configuration d'based on the above-mentioned viewpoint IV.
If the burst strength of the single flute at the portion including the fold F is less than the predetermined burst strength range, it is presumed that the problem IV is caused by the insufficient load capacity of the sheet 2.
The "predetermined burst strength range" of the configuration d'is 500 [kPa] or more, preferably 650 [kPa] or more, and more preferably 1500 [kPa] or more.

<Structure d ″>
As described above, the configuration d ″ is described in the corrugated cardboard material 1 made of double-sided corrugated cardboard with double flutes, “a configuration 4 in which the burst strength at a portion not including the crease F is within a predetermined burst strength range” and “crease F”. 5 ”is provided, in which the burst strength of the portion including the above is within a predetermined burst strength range.
The “burst strength” of the configuration d ″ is the burst strength of the portion not including the fold F and the portion including the crease F, respectively, except that the “burst strength” described in the configurations d and d ′ is described above. It is the same as "strength".
The inventors of the present application have determined that the burst strength of the sheet 2 of the double flute cardboard material 1 that does not include the fold F is within the predetermined burst strength range and the burst strength of the portion that includes the crease F is predetermined. It was found that the above-mentioned problem IV tends to be suppressed within the burst strength range of. Conversely, it was found that the sheet 2 having the burst strength at the portion including the fold F outside the range of the configuration d ″ tends to cause the problem IV.

That is, the sheet 2 is provided with a configuration d ″ based on the above-mentioned viewpoint IV.
In the double flute sheet 2, the burst strength of the portion not including the crease F is below the predetermined burst strength range, or the burst strength of the portion including the fold F is below the predetermined burst strength range. If so, it is presumed that the problem IV is caused by the insufficient load capacity of the sheet 2.
The "predetermined burst strength range" of the portion of the configuration d ″ that does not include the fold F is 500 [kPa] or more, preferably 700 [kPa] or more, and 1000 [kPa] or more. Is more preferable. The "predetermined burst strength range" of the portion including the fold F is 520 [kPa] or more, preferably 800 [kPa] or more, and more preferably 1500 [kPa] or more.

Further, the inventors of the present application tend to suppress the above-mentioned problem IV as the burst strength of the portion not including the crease F and the burst strength of the portion including the crease F are increased, while the crease We also found that damage is likely to occur at point F. That is, if the burst strength exceeds a predetermined upper limit, it is presumed that damage is likely to occur at the crease F. Here, the damage includes cracking, tearing, tearing, etc. of the liner at the crease. The crease portion is an area including the periphery of the fold.
The predetermined upper limit of the burst strength of the portion including the fold F and the portion including the crease F is 2500 [kPa], and 2250 from the viewpoint of obtaining a bellows-folded cardboard material in which the crease F is less likely to be cracked. It is preferably [kPa], and more preferably 2000 [kPa].

<Structure e>
As described above, the configuration e includes "a configuration in which the adhesive force is within a predetermined force range".
The "adhesive force" of the configuration e is a parameter corresponding to the strength of bonding the core 2c of the sheet 2 and the liners 2a and 2b.
The "adhesive force" referred to here is the adhesive force between the core 2c and the front liner 2a (adhesive force on the glue machine side) and the adhesive force between the core 2c and the back liner 2b (adhesion on the single facer side). It means the average value with (force).

The inventors of the present application have found that the above-mentioned problem V tends to be suppressed if the adhesive force of the sheet 2 is within a predetermined force range. Conversely, it was found that the sheet 2 having an adhesive strength outside the range of the configuration e tends to cause the problem V.
That is, the sheet 2 is provided with the configuration e based on the above-mentioned viewpoint V.
If the adhesive force is less than the predetermined force range, it is presumed that the liners 2a and 2b are likely to be peeled off from the core 2c when the cardboard material 1 is manufactured in the box, which causes a problem V.
The "predetermined force range" of the configuration e is 140 [N] or more, preferably 190 [N] or more, and more preferably 220 [N] or more.

[3. Action and effect]
By providing at least one of the above-mentioned configurations a to e, the corrugated cardboard material 1 of the present embodiment can manufacture a box in a good state when used as a box-making material.
According to the configuration a, since the thickness dimension of the sheet 2 is within a predetermined dimension range and the planar compressive strength is within a predetermined compressive strength range, the box-making property of the corrugated cardboard material 1 can be ensured, and the box can be made. It is possible to suppress breakage of the bent portion when assembling the cardboard.
According to the configuration b, since the planar compressive strength of the sheet 2 is in a predetermined compressive strength range and the step-by-step ratio is in a predetermined magnification range, the box-making property of the corrugated cardboard material 1 can be ensured.
According to the configuration c, since the angle ratio of the sheet 2 is within a predetermined ratio range, it is possible to ensure the suitability when the cardboard material 1 is printed.
According to the configurations d and d', since the burst strength of the sheet 2 is within a predetermined burst strength range, it is possible to suppress the tearing of the box assembled from the corrugated cardboard material 1.
According to the configuration d ″, the burst strength of the portion of the double flute that does not include the crease F is within the predetermined burst strength range, and the burst strength of the portion that includes the crease F is within the predetermined burst strength range. Therefore, it is possible to suppress the tearing of the box assembled from the cardboard material 1.
According to the configuration e, since the adhesive force of the sheet 2 is within a predetermined force range, it is possible to prevent the liners 2a and 2b of the box assembled from the cardboard material 1 from peeling off.

[II. Example]
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.
In this item [II], items common to the examples and comparative examples of configurations a to e are described in item [1], and examples and comparative examples corresponding to each of configurations a to e are described in item [2]. .. Further, an example in which three of the configurations a to e are combined will be described in item [3].

[1. Common subject matter]
In the examples and comparative examples of the configurations a to e, a configuration common to the corrugated cardboard material (hereinafter referred to as “measurement corrugated cardboard material”) for which the parameter is measured will be described.
--Measurement target--
The measurement cardboard material is a double-sided cardboard sheet.
This measured corrugated cardboard material has the following size.
・ Size: Vertical dimension 1300 [mm],
Horizontal dimension 1150 [mm],
Height dimension 1800 [mm]

--Preprocessing--
The measurement corrugated cardboard material or a part thereof, which is the object of parameter measurement, was pretreated for 24 hours or more under temperature and humidity conditions of temperature 23 [° C.] and humidity 50 [%] in accordance with JIS Z0203. Then, each parameter was measured.
In addition, a commonly used one-tank type starch paste was used as the adhesive for corrugated cardboard to bond the liner base paper and the core base paper. Further, the corrugated cardboard material to be measured was manufactured using a corrugator having a stepped roll.
--Evaluation--
Each of the examples and comparative examples, which will be described in detail in the next item [2], was evaluated on a four-point scale of “◎”, “○”, “△”, and “×”.

[2. Configuration a to e]
<Structure a>
--Measurement target--
The measurement corrugated cardboard materials used in Examples a1 to a6 and Comparative Examples a7 to a9 regarding the configuration a were produced by using a corrugator having a stepped roll having a stepped number of 34 [mountain / 30 cm]. The "number of steps" corresponds to the number of peaks (steps) per 30 [cm] on the sheet, and corresponds to a value obtained by dividing 30 [cm] by the wavelength of the step.

Hereinafter, with respect to Examples a1 to a6 and Comparative Examples a7 to a9, the type of flute, the step height of the stepping roll, and the basis weight of the base paper will be described.
In Examples a1 to a6 and Comparative Examples a7 to a9, either a single flute or a double flute was adopted as shown below.
Single flute: Examples a1 to a3, a5, a6 and Comparative Examples a8, a9
-Double flute: Example a4 and Comparative Example a7

Examples a1 to a6 and Comparative Examples a7 to a9 were manufactured by a step-rolling roll set to any one of the five step heights as listed below. The "step height" is a dimension corresponding to the height of the step in the sheet of the corrugated cardboard material to be measured and corresponding to the amplitude of the step.
-Step height 0.5 [mm]: Comparative example a9
-Step height 1.5 [mm]: Example a1
-Step height 3.1 [mm]: Example a2
Step height 4.5 [mm]: Examples a3 to a6, Comparative Example a8
-Step height 4.7 [mm]: Comparative example a7

In Examples a1 to a6 and Comparative Examples a7 to a9, the common liner base paper shown below was used.
・ Liner base paper: 160 [g / m ² ] [MC160: manufactured by Oji Materia Co., Ltd.]
On the other hand, in Examples a1 to a6 and Comparative Examples a7 to a9, core base papers having various basis weights prepared according to the production method published in JP-A-2018-162526 were used. Specifically, one of the five types of basis weights shown below was adopted for each of Examples a1 to a6 and Comparative Examples a7 to a9. The basis weights listed here are the basis weights of the base paper that is the material (raw material) of the corrugated cardboard material to be measured.
Basis weight (of core base paper) 60 [g / m ² ]: Comparative example a8
Basis weight (of core base paper) 80 [g / m ² ]: Example a6
Basis weight 170 [g / m ² ] (of core base paper): Example a5
Basis weight 250 [g / m ² ] (of core base paper): Examples a1 to a4, Comparative example a9
Basis weight 320 [g / m ² ] (of core base paper): Comparative example a7

Measurement The basis weight of the base paper (liner base paper, core base paper) used as the material for the corrugated cardboard sheet was measured by the following procedures xa to xd.
-Procedure xa: Pre-treat the base paper for measuring the basis weight according to JIS Z0203.
-Procedure xb: Cut out the base paper to a size of 250 [mm] x 400 [mm].
-Procedure xc: The weight of the base paper cut out in procedure xb is measured with an electronic balance.
-Procedure xd: The weight measured in procedure xc is the weight per unit square meter [g / m ^2]
] Is converted.

The basis weight of the liner (base paper) forming the sheet of the corrugated cardboard material is measured by the following procedures ya to yf.
-Procedure ya: Immerse the sheet of measurement cardboard material in tap water for 15 [minutes].
-Procedure yb: Peel off the liner, core and hand of the sheet immersed in procedure ya.
-Procedure yc: The liner peeled off in procedure yb is dried in a dryer at 105 [° C.] for 20 [minutes].
dry.
-Procedure yd: The liner dried in the procedure yc is 250 [mm] x 400 [mm] size.
Cut out to.
-Procedure yes: The weight of the liner cut out in the procedure yd is measured with an electronic balance.
-Procedure yf: The weight measured in procedure yes is the weight per unit square meter [g / m ^2]
] Is converted.

Further, the basis weight of the core (base paper) forming the sheet of the corrugated cardboard material is measured by the following procedure za to zg.
-Procedure za: Immerse the sheet of measurement cardboard material in tap water for 15 [minutes].
-Procedure zb: The liner, core and hand of the sheet immersed in procedure z are peeled off by hand.
-Procedure zc: The liner peeled off in procedure zb is dried in a dryer at 105 [° C.] for 20 [minutes].
dry.
-Procedure zd: Pre-treat the liner that measures the basis weight in accordance with JIS Z0203.
-Procedure ze: Cut out a liner to a size of 250 [mm] x 400 [mm]. In addition, the wave
If the shape structure remains, cut it out to this size while keeping the waves stretched.
Su.
-Procedure zf: The weight of the liner cut out in the procedure ze is measured with an electronic balance.
-Procedure zg: Weight measured by procedure zf is the weight per unit square meter [g / m ²
] Is converted.

In addition, the basis weight of the liner and core that form the sheet of the measured corrugated cardboard material is the basis weight of the base paper that is the material of the measured corrugated cardboard material, even if the same base paper is used as the measurement target. The measured value of is variable by about ± 10 [%].
For the above-mentioned measured corrugated cardboard material, the thickness dimension and the planar compressive strength shown in Table 3 below were measured.

The "thickness dimension" is a parameter corresponding to the thickness of each sheet in the measured corrugated cardboard material. This thickness dimension was measured by the following procedures aa to ad.
-Procedure aa: Half the number of steps (that is, the middle step) of the total number of steps of the measured corrugated cardboard material
Collect 5 upper and lower sheets as a reference. Specifically, the measurement cardboard material
When the total number of stages M is odd, the number of stages is half of the total number of stages of the measured corrugated cardboard material.
Five steps above and below based on the step rounded off by M / 2 (that is, the middle step)
Collect the sheet. When the total number of stages M of the corrugated cardboard material is even, the measurement da
Up and down five based on half the number of stages [(M / 2) + 1] of the total number of stages of the ball material
Sheets for the steps were collected. When collecting test pieces, the steps should not be crushed.
I was careful.
-Procedure ab: 5 [cm] x 5 [cm] size from 10 sheets collected in procedure aa
Cut out a test piece into a square.
-Procedure ac: Measure the thickness of the test piece cut out in procedure ab according to the following standards, measuring equipment, and measurement.
Measure under constant conditions.
> Compliant standard: Corrugated cardboard industry standard T0004: 2000
> Measuring equipment: Thickness gauge (Mitutoyo Ratchet, model number K470101K)
> Measurement conditions: Plunger diameter 16 [mm], load 3923 [mN]
-Procedure ad: A disturbance that reduces the accuracy of the measurement result from the thickness measured by procedure ac (required)
Exclude the numerical values that can be (cause) (so to speak, the numerical values that deviate greatly), and calculate the average value.
The thickness was taken.
In the "exclusion of numerical values that can cause disturbance" in step ad, when each numerical value measured in procedure ac is used as a population, the numerical value whose standard deviation of the population deviates from ± 3σ is excluded.

"Plane compressive strength" is a parameter corresponding to the resistance of the corrugated cardboard sheet to be crushed. This planar compressive strength was measured by the following procedures aA to aD.
-Procedure aA: Similar to procedure aa, based on half the total number of stages of the measured corrugated cardboard material.
Collect the upper and lower five-tiered sheets.
-Procedure aB: A circular test with a diameter of 6.4 [cm] from ten sheets collected in procedure aA.
Cut out a test piece.
-Procedure aC: Measure the planar compressive strength of the test piece cut out in step aB according to the following standard and measurement.
Measure under the measurement conditions of equipment, test speed and parallelism. The parallelism is flat.
Indicates the degree of parallelism between the top and bottom of the jig for surface compression.
> Compliant standard: JIS Z 0403-1
> Measuring equipment: Compression with a jig for flat compression (manufactured by Tester Sangyo Co., Ltd.)
Testing machine (manufactured by A & D Co., Ltd., RTF1350)
> Test speed (measurement conditions): 12.5 ± 2.5 [m / min]
> Parallelism (measurement condition): 1/1000 or less of the compressive dimension-Procedure aD: Measured from the plane compressive strength measured in step aC in the same way as step a above
Exclude numerical values that can cause disturbances (factors) that reduce the accuracy of constant results, and are flat.
The average value was taken as the plane compression strength.

--Evaluation--
For Examples a1 to a6 and Comparative Examples a7 to a9 in which the thickness dimension and the planar compressive strength were measured as described above, each of the box-making property and the ruled cracking described below was evaluated.
"Box making" depends on the accuracy of the box in which the cardboard pieces (hereinafter referred to as "evaluation cardboard pieces") cut out by the cut line straddling the folds of the measured cardboard material are assembled by hand (handmade). Corresponding evaluation criteria. As a manual assembly method, the cut corrugated cardboard piece was folded at a predetermined ruled line, attached with a hot melt adhesive, and boxed.
The method of assembling the evaluation cardboard pieces by the box-making system is the same regardless of whether the evaluation cardboard pieces are assembled by hand or by the box-making system. Therefore, it can be said that the box-making property of the evaluation cardboard piece assembled by hand has a correlation with the box-making property of the evaluation cardboard piece assembled by the box-making system.

The "evaluation cardboard piece" is a test piece in which the measurement cardboard material is punched into the following shape and size with a sample cutter (CF2-1218 manufactured by Mimaki Engineering Co., Ltd.).
-Shape: Pattern in which the A-type cardboard box is developed-Size: Width dimension of the side plate of the A-type cardboard box 356 [mm],
Width dimension of the end plate of the A type cardboard box 159 [mm],
Height dimension of A type cardboard box 256 [mm]
・ Number of sheets: 100 [sheets]

The above evaluation cardboard pieces were evaluated according to the following criteria.
-⊚: All (100 [sheets]) evaluation cardboard pieces have good box-making properties.
-○: Evaluation of 100 [sheets] Of the cardboard pieces, 1 to 2 [sheets] have poor box-making properties.
-Δ: Evaluation of 100 [sheets] 3 [sheets] of the corrugated cardboard pieces have poor box-making properties.
-X: Evaluation of 100 [sheets] Of the cardboard pieces, 4 [sheets] or more have poor box-making properties.
In Example a4, in which the evaluation of “◯” was obtained with respect to the box-making property, the box-making property of 2 [sheets] was poor.

The term "good box-making property" as used herein means that the distance dimension between the following folded portions A and B in the evaluated corrugated cardboard piece is less than the predetermined distance dimension.
-Folded part A: A part where a ruled line for box making (an element different from the fold) is provided.-Folded part B: A part actually folded when assembled in a box (during box making) "Predetermined distance" The "dimensions" are 2.0 [mm] for the dimension perpendicular to the crease of the evaluation cardboard piece (MD direction) and 5 [mm] for the dimension in the direction parallel to the crease (CD direction). ].
On the other hand, "poor box-making property" means that the distance dimension between the folded portions A and B in the evaluated corrugated cardboard piece is equal to or larger than the predetermined distance dimension.

Further, "line cracking" means that the bent portion is broken when the evaluation cardboard piece is assembled into the box. This rule cracking is observed by visually observing a box whose box-making property has been evaluated (that is, a box in which evaluation cardboard pieces are assembled, hereinafter referred to as an "evaluation box").
This rule crack was evaluated according to the following criteria.
-⊚: No cracking was observed in all (100 [box]) evaluation boxes.
-○: Of the 100 [box] evaluation boxes, 1 to 2 [boxes] were cracked.
-Δ: Cracks were found in 3 [boxes] of the 100 [boxes] evaluation boxes.
-X: Of the 100 [box] evaluation boxes, 4 [boxes] or more were cracked.
Regarding Examples a3, a5, a6 and Comparative Example a8 in which the evaluation of "○" was obtained for the rule cracking, the rule cracking was observed in 1 [box] in Examples a3, a5, a6, and Comparative Example a8. In 2 [box], a crack was seen.

In Examples a1 to a6, the thickness dimension is 2.0 [mm] or more and 9.6 [mm] or less, and the planar compressive strength is 50 [kPa] or more and 250 [kPa] or less. , A good evaluation of at least "Δ" or more was obtained in both box-making property and rule cracking.
On the other hand, in Comparative Examples a7 and a9 having a thickness dimension outside the range of 2.0 to 9.6 [mm] and Comparative Examples a7 to a9 having a planar compressive strength outside the range of 50 to 250 [kPa]. A poor evaluation of "x" was obtained for the box-making property. Further, in Comparative Example a7 in which the thickness dimension was larger than 9.6 [mm], the evaluation of the rule cracking was also a poor evaluation of “x”.

From Comparative Example a7, if the thickness dimension is larger than 9.6 [mm], the liner base paper cannot be stretched and breaks when it is bent by the ruled line for box making, and the evaluation of the ruled crack is poor. Inferred.
From this comparative example a7, when the plane compression strength is larger than 250 [kPa], it becomes difficult to insert a ruled line for box making (due to a decrease in the formability of the ruled line), and a place other than the ruled line for box making It is also presumed that the box-making property is evaluated poorly because it is bent at.

From Comparative Example a8, when the plane compression strength is less than 50 [kPa], the bending strength of the evaluation cardboard piece is insufficient and it becomes easy to bend at a place other than the ruled line for box making, and the box making property is evaluated. Is presumed to be defective.
Similarly, from Comparative Example a9, when the thickness dimension is less than 2.0 [mm], the bending strength of the evaluated corrugated cardboard piece is insufficient and it becomes easy to bend at a place other than the ruled line for box making. It is presumed that the evaluation of corrugated cardboard is poor.

In view of the above Comparative Examples a7 to a9, it is presumed from Examples a1 to a6 that the smaller the thickness dimension is in the range of 9.6 [mm] or less, the more the occurrence of rule cracking is suppressed. On the other hand, it is presumed that the larger the thickness dimension in the range of 2.0 [mm] or more, the more the bending at the place other than the ruled line for box making can be suppressed.
From Examples a1 to a6, it can be inferred that if the planar compression strength is 250 [kPa] or less, defects in the ruled lines formed for box making can be suppressed. On the other hand, if the planar compression strength is 50 [kPa] or more, it is presumed that the bending strength of the evaluated corrugated cardboard piece is secured and the bending is suppressed at a place other than the ruled line for box making.
Therefore, if the thickness dimension is 2.0 [mm] or more and 9.6 [mm] or less, and the planar compressive strength is 50 [kPa] or more and 250 [kPa] or less, the box-making property It can be said that it is possible to both secure and suppress rule cracking.

<Structure b>
--Measurement target--
As the measurement corrugated cardboard materials used in Examples b1 to b3 and Comparative Examples b4 and b5 regarding the configuration b, the same liner base papers as in Examples a1 to a6 and Comparative Examples a7 to a9 were used, and the following core base papers were used.
-Core base paper: 170 [g / m ² ] [LB170: manufactured by Oji Materia Co., Ltd.]
Further, the measurement corrugated cardboard materials used in Examples b1 to b3 and Comparative Examples b4 and b5 were manufactured by using a corrugated board having a stepping roll having various stepping rates shown in Table 4 below. Further, for each of Examples b1 to b3 and Comparative Examples b4 and b5, the planar compressive strength was measured in the same procedure as the above-mentioned procedures aA to aD, and the planar compressive strength shown in Table 4 below was measured. ..

The "step ratio" is a parameter corresponding to the magnification of the length dimension in the MD direction with respect to the liner of the core. This step-by-step rate was measured by the following procedures ba to bg.
-Procedure ba: Similar to procedures aa and aA, half the total number of stages of the measured corrugated cardboard material.
Collect the upper and lower five-tiered sheets based on.
-Procedure bb: The direction in which the core peaks are continuous from the ten sheets collected in procedure ba (horizontal)
20 [cm] in the direction (MD direction) and orthogonal to the core peak (vertical)
Cut out to a size of 10 [cm] in the direction (direction, CD direction).
-Procedure bc: The test piece cut out in procedure bb is immersed in tap water for 24 hours.
-Procedure bd: After immersion in procedure bc, the liners on the front and back are peeled off and the core is taken out.
-Procedure be: The length of the core taken out in step bd is stretched by hand and fully extended.
With a ruler.
-Procedure bb: The "extended length of the core" measured in procedure be and cut out in procedure bb.
The length of the core of the test piece in the continuous direction ("Original cardboard sheet"
The step ratio is called "length", here 20 [cm]), and the following formula b is used.
Is calculated.
Step ratio = length when the core is fully extended / length of the original cardboard sheet ... Equation b
-Procedure bg: Measured from the step-by-step rate calculated in procedure bf in the same manner as in steps ad and aD above.
Exclude numerical values that can cause disturbances (factors) that reduce the accuracy of constant results, and are flat.
The average value was taken as the step-by-step rate.

--Evaluation--
The box-making property was evaluated for Examples b1 to b3 and Comparative Examples b4 and b5 for which the step-by-step ratio was obtained as described above. This box-making property is synonymous with the box-making property used in the evaluation of Examples a1 to a6 and Comparative Examples a7 to a9. In Example b1 in which the evaluation of “◯” was obtained with respect to the box-making property, the box-making property of 2 [sheets] was poor.

In Examples b1 to b3, the step ratio is 1.2 [times] or more and 1.7 [times] or less, and the planar compressive strength is 50 [kPa] or more and 250 [kPa] or less. Yes, a good evaluation of at least "Δ" or higher was obtained for the box-making property.
On the other hand, Comparative Example b4 in which the stepwise ratio is less than 1.2 [times] and the planar compressive strength is less than 50 [kPa], and the planar compressive strength is larger than 1.7 [times] and the planar compressive strength. In Comparative Example b5 in which the value is larger than 250 [kPa], a poor evaluation of “x” in box-making property was obtained.

From Comparative Example b4, since the step-by-step ratio is less than 1.2 [times] and the planar compressive strength is less than 50 [kPa], the bending strength of the evaluated corrugated cardboard piece is insufficient, so that the box is manufactured. It is presumed that the box-making property will be poorly evaluated because it will be easily bent at places other than the corrugated cardboard.
From Comparative Example b5, it becomes difficult to insert a ruled line for box making (formation of a ruled line) because the step ratio is larger than 1.7 [times] and the planar compressive strength is larger than 250 [kPa]. It is presumed that the evaluation of the box-making property will be poor because it is bent at a place other than the ruled line for box-making (due to the deterioration of the property).

In view of the above comparative examples b4 and b5, from Examples b1 to a3, the step-by-step ratio is 1.2 [times] or more, and the planar compressive strength is 50 [kPa] or more. It is presumed that bending at places other than the ruled lines for boxes can be suppressed. Further, it is presumed that the defect of the ruled line formed for box making can be suppressed by the step-by-step ratio of 1.7 [times] or less and the planar compressive strength of 250 [kPa] or less.
Therefore, if the step ratio is 1.2 [times] or more and 1.7 [times] or less, and the planar compressive strength is 50 [kPa] or more and 250 [kPa] or less, the box is manufactured. It can be said that sex can be secured.

<Structure c>
--Measurement target--
In Examples c1 to c3 and Comparative Example c4 regarding the configuration c, the same base papers as in Examples b1 to b3 and Comparative Example b4 are used, and A produced by using a corrugator having a stepping roll of the specifications shown below. Measurement of flute A cardboard material was used.
・ Step height: 4.5 [mm]
・ Number of steps: 34 [mountain / 30 cm]
Then, the measured corrugated cardboard materials manufactured so as to have the angle ratios shown in Table 5 below were used in Examples c1 to c3 and Comparative Example c4. The unit [-] in Table 5 represents a dimensionless quantity.

The "angle ratio" is a parameter corresponding to the degree of inclination of the step in the sheet of the corrugated cardboard material to be measured. This angle ratio was measured by the following procedures ca to cf.
-Procedure ca: In the sheet of corrugated cardboard material to be measured, one mountain of the core is vertically oriented (CD direction).
Take a photo from Mukai).
-Procedure cb: One mountain will have a height of 10 [cm] or more in the photograph taken in procedure ca.
Enlarge and print on printing paper.
-Procedure cc: The direction parallel to the front and back liners (that is, the lateral direction <MD direction>).
Draw an auxiliary line that passes through the center of the front liner and back liner (center in the TD direction).
-Procedure cd: Of the intersections between the auxiliary line drawn in procedure cc and the core, any two adjacent points
select.
-Procedure ce: At each of the two points selected in procedure cd, the auxiliary line and the core form
The acute angle of the angles was measured with a protractor.
-Procedure cf: Two absolute values of the difference between the two angles (measured values) measured in procedure ce
Calculate the ratio divided by the sum of the angles of.

--Evaluation--
The printability of Examples c1 to c3 and Comparative Example c4 from which the angle ratios were obtained as described above was evaluated.
"Printability" is the suitability when printing is applied to the measured corrugated cardboard material, and is an evaluation standard corresponding to the quality of printing applied to the measured corrugated cardboard material.
This printability was evaluated by the following procedures cA to cC.
-Procedure cA: Measured cardboard sheet of 500 [mm] x 1350 [mm]
Cut into pieces.
-Procedure cB: Direct flexo printing machine D for the test piece cut in procedure cA.
550 [Line / Inn] by YNA FLEX160 (manufactured by Bobst)
Aqueous flexo ink (Sakata Inn) with Anilox roll engraved on [C]
It was painted and printed in the following order (manufactured by Ku).
> Order of coating: red → ink → indigo → yellow → varnish ・ Procedure cC: The finish printed in procedure cB was visually observed.

The above printability was evaluated according to the following criteria.
-◎: There is no uneven ink deposition, and the print finish is good.
-○: There is almost no uneven ink deposition, and there is no practical problem.
-△: There is a little unevenness in ink deposition, but there is no practical problem.
・ ×: There is a great deal of uneven ink deposition, there are practical problems, and the quality is significantly inferior.

In Examples c1 to c3, the angle ratio is 0.30 or less, the printability is evaluated as “Δ” or more, and there is no practical problem. In Examples c1 and c2 having an angle ratio of 0.15 or less, an evaluation of “◯” or higher was obtained, and in Example c1 having an angle ratio of 0.05 or less, an evaluation of “⊚” was obtained.
On the other hand, in Comparative Example c4 in which the angle ratio is larger than 0.30, an evaluation of “x” is obtained for printability, which poses a practical problem.

From Comparative Example c4, it is presumed that when the angle ratio is larger than 0.30, the heights of the steps become uneven, and the evaluation of printability becomes poor. Alternatively, the fact that the test piece is likely to be deformed in the direction corresponding to the inclination of the step when the ink is applied is another reason for presuming that the evaluation of printability is poor.
On the other hand, from Examples c1 to c3, it is presumed that when the angle ratio is 0.30 or less, the variation in the height of the steps is suppressed, and printability without any problem in practical use can be obtained. The variation in the height of the steps is surely suppressed by the angle ratio of 0.15 or less from Examples c1 and c2, and more by the angle ratio of 0.05 or less from Example c1. It is presumed that it will be further suppressed.
Therefore, if the angle ratio is 0.30 or less, it can be said that printability can be ensured.

<Structure d>
--Measurement target--
For Examples d1 to d3 and Comparative Example d4 regarding the configuration d, the same core base paper as in Examples b1 to b3, c1 to c3 and Comparative Examples b4 and c4 was used. On the other hand, in Examples d1 to d3 and Comparative Example d4, liner base papers having various basis weights produced according to the method for producing a liner for corrugated board of Japanese Patent No. 6213364 were used. Specifically, one of the four types of basis weights shown below was adopted for each of Examples d1 to d3 and Comparative Example d4.
Basis weight (of liner base paper) 90 [g / m ² ]: Example d1
Basis weight 170 [g / m ² ] (of liner base paper): Example d2
Basis weight (of liner base paper) 250 [g / m ² ]: Example d3
Basis weight (of liner base paper) 60 [g / m ² ]: Comparative example d4
In addition, a corrugated cardboard material produced by using a corrugated board having the same stepping rolls as in Examples c1 to c3 and Comparative Example c4 was used.
The burst strength was measured for each of Examples d1 to d3 and Comparative Example d4 using the measured corrugated cardboard material produced as described above, and the burst strength shown in Table 6 below was measured.

The “burst strength” is a parameter corresponding to the easiness of tearing of the evaluation box (IFC code: 0401) targeted for evaluation of rule cracking in the above configuration a. This burst strength was measured by the following procedures da to dd.
-Procedure da: Similar to procedure aa, the number of stages of the measured corrugated cardboard material is half of the total number of stages.
Collect the upper and lower five-tiered sheets.
-Procedure db: 100 [mm] x 100 [mm] from ten sheets collected in procedure da
] Cut out a test piece into a square of size.
-Procedure dc: Measure the thickness of the test piece cut out in step db according to the following standard, test piece, and measurement.
Measure with equipment and measurement conditions.
> Compliant standard: JIS P 8131 (paperboard-burst strength test method)
> Measuring equipment: Murren burst tester EH, manufactured by Toyo Seiki Seisakusho Co., Ltd.
> Measurement conditions: The pressure when expanded to a height of 10 [mm] from the tightening surface is 1.
Use a rubber diaphragm of 70 to 220 [kpa] ・ Procedure dd: Similar to procedure ad, aD, bb, from the burst strength measured in procedure dc,
Excluding numerical values that can cause disturbances (factors) that reduce the accuracy of measurement results,
The average value was taken as the burst strength.

--Evaluation--
The tearability of the evaluation box was evaluated for Examples d1 to d3 and Comparative Example d4 in which the burst strength was obtained as described above.
"Easiness of tearing" is an evaluation standard corresponding to the light and heavy load capacity of the contents contained in the box. This easiness of tearing was evaluated by the following procedures dA to dC.
-Procedure dA: Weights are added so that the weight per unit area is 15 [kgf / cm ² ].
Store in an evaluation box. The evaluation box is an assembly type so that it will not be affected by the tape.
IFC code 0401).
-Procedure dB: After procedure dB, two workers hold the bottom surface where the weight is not in contact with the evaluation box.
Raise and hold for 30 [seconds].
-Procedure DC: Visually check whether or not the evaluation box has been torn in procedure dB.

The above-mentioned fragility was evaluated according to the following criteria.
・ ◎: The appearance of the evaluation box has not changed at all after being lifted.
・ ○: The evaluation box is slightly torn after being lifted, but the weight remains in the evaluation box.
・ △: The evaluation box is torn after being lifted, but the weight stays in the evaluation box.
・ ×: The evaluation box is severely torn after being lifted, and the weight falls from the evaluation box.

In Examples d1 to d3, the burst strength was 500 [kPa] or more, the easiness of tearing was evaluated as “Δ” or more, and the weight did not fall. In Examples d2 and d3 having a burst strength of 1000 [kPa] or more, an evaluation of "○" or more was obtained, and in Example d3 having a burst strength of 2000 [kPa] or more, an evaluation of "◎" was obtained. ..
On the other hand, in Comparative Example d4 having a burst strength of less than 500 [kPa], an evaluation of “x” was obtained for the ease of tearing, and the weight fell.

Therefore, if the burst strength is 500 [kPa] or more, it can be said that it is possible to prevent the contents from falling out of the evaluation box. Further, if the burst strength is 1000 [kPa] or more, it can be said that damage to the evaluation box due to the load of the contents can be suppressed. Moreover, if the burst strength is 2000 [kPa] or more, it can be said that damage to the evaluation box due to the load of the contents can be prevented.
In addition, it can be seen that the larger the basis weight of the liner base paper, the higher the burst strength. From such a correlation between the basis weight and the burst strength, it can be said that if the basis weight is 80 [g / m ² ] or more, it is possible to prevent the contents from falling out of the evaluation box. Further, when the basis weight is 160 [g / m ² ] or more, it can be said that damage to the evaluation box due to the load of the contents can be suppressed. Moreover, if the basis weight is 240 [g / m ² ] or more, it can be said that damage to the evaluation box due to the load of the contents can be prevented.

<Structure d', d''>
--Measurement target--
Of the examples d10 to d24 and the comparative examples d25 and d26 relating to the configurations d'and d', the thickness and the basis weight of the measured corrugated cardboard materials of the examples d10, d11, d12 and the comparative example d25 are described above. It is the same as the measurement corrugated cardboard material of Example d1, d2, d3 and Comparative Example d4. In each of the measured corrugated cardboard materials of Examples d13 to d24 and Comparative Example d26, the thickness and the basis weight are different from the measured corrugated cardboard materials of Examples d1, d2, d3 and Comparative Example d4 described above.

Specifically, for each of the measurement cardboard materials of Examples d10 to d24 and Comparative Examples d25 and d26, one of the four types of flutes shown below was adopted.
・ A flute (single flute)
・ B flute (single flute)
・ E flute (single flute)
・ AB flute (double flute)

The measurement cardboard material of each flute used in each of Examples d10 to d24 and Comparative Examples d25 and d26 was produced by using a corrugator having a stepped roll of the specifications shown below.
> A flute ・ Step height: 4.5 [mm]
・ Number of steps: 34 [mountain / 30 cm]
> B flute ・ Step height: 2.5 [mm]
・ Number of steps: 50 [mountain / 30 cm]
> E flute ・ Step height: 1.1 [mm]
・ Number of steps: 85 [mountain / 30 cm]
＞ AB Flute ――A Flute――
・ Step height: 4.5 [mm]
・ Number of steps: 34 [mountain / 30 cm]
--B flute--
・ Step height: 2.5 [mm]
・ Number of steps: 50 [mountain / 30 cm]

Of the above four types of flutes, the single flutes that make up the A flute, B flute, and E flute correspond to one core (“core 2” in Tables 7 to 9 below) and two liners, respectively. It is composed of three base papers (materials). The double flute that forms the AB flute consists of three cores (“core 1”, “core 2”, and “core 3” in Tables 7 to 9 below) and five base papers corresponding to each of the two liners. It is composed of (materials).

In Examples d10 to d24 and Comparative Examples d25 and d26, any one of the following ten types of corrugated cardboard base paper was used for each of the base papers forming the core or liner constituting the respective measurement cardboard materials.
・ No. 1: Basis weight 90 [g / m ² ], density 0.77 [g / cm ³ ]
・ No. 2: Basis weight 170 [g / m ² ], density 0.86 [g / cm ³ ]
・ No. 3: Basis weight 250 [g / m ² ], density 0.87 [g / cm ³ ]
・ No. 4: Basis weight 60 [g / m ² ], density 0.72 [g / cm ³ ]
・ No. 5: Basis weight 160 [g / m ² ], density 0.86 [g / cm ³ ]
・ No. 6: Basis weight 120 [g / m ² ], density 0.78 [g / cm ³ ]
・ No. 7: Basis weight 170 [g / m ² ], density 0.85 [g / cm ³ ]
・ No. 8: Basis weight 170 [g / m ² ], density 0.68 [g / cm ³ ] [LB 170:
Made by Oji Materia Co., Ltd.]
・ No. 9: Basis weight 120 [g / m ² ], density 0.59 [g / cm ³ ] [S 120:
Made by Oji Materia Co., Ltd.]
・ No. 10: Basis weight 280 [g / m ² ], density 0.85 [g / cm ³ ]

No. above. The method of making the base paper of No. 1 is to use softwood kraft pulp and corrugated cardboard waste paper as raw materials, make paper using a multi-layer paper machine, and have a basis weight of 90 [g / m ² ] composed of three layers. It creates a cardboard base paper. The papermaking conditions were that the cationic paper strength enhancer was contained in an amount of 0.5 [parts by mass] with respect to a total of 100 [parts by mass] of the total pulp of the paper layer, and 10 of the surface pulps were coniferous kraft pulp. It was contained in a proportion of [mass%]. In addition, all the cationic paper strength enhancers were contained in the surface layer. The softwood kraft pulp accounted for 6 [mass%] of the total pulp in the paper layer.

The above No. 1-No. In order to adjust the density of the base paper in No. 10, the nip pressure was adjusted by the calendering process in the papermaking process at the time of making the base paper. The density was measured by a measuring method according to JIS P8118: 1998.
Except for the fact that the density was adjusted, the above No. 2-No. 6, No. The method for producing the base paper of No. 10 is No. 1 except for the basis weight. This is the same creation method as in 1. The above No. The method for producing the base paper of No. 7 was No. 7 except that the surface layer pulp contained softwood kraft pulp in a proportion of 50% by mass. It is the same creation method as 2.
The burst strength was measured for each of Examples d10 to d24 and Comparative Examples d25 and d26 using the measured corrugated cardboard material manufactured as described above, and the burst strengths shown in Tables 7 to 9 below were measured. It was.

The burst strength was evaluated in the same way as the above-mentioned "burst strength" except that it was measured at each of the points without creases (without creases) and the points with creases (with creases). This is a parameter corresponding to the fragility of the box (IFC code: 0401).
In order to measure the burst strength without creases and the burst strength with creases, the test pieces without creases and the test pieces with creases were used for Examples d10 to d24 and Comparative Examples d25 and d26, respectively. Two types of test pieces were prepared.

For both the test piece without creases and the test piece with creases, a sample cutter (CF2-1218 manufactured by Mimaki Engineering Co., Ltd.) was used from an A4 size cardboard sheet cut out from an arbitrary stage of the measurement cardboard material. It is a test piece cut out with the following dimensions.
-Dimensions: Vertical dimension 100 [mm]
Horizontal dimension 100 [mm]
Further, the test piece with creases is a test piece having the following creases in the test piece having the above dimensions. In addition, for the measurement of the burst strength, a test piece having no creases, scratches, dents, etc. other than the intentionally provided creases is used.
・ Fold: Passes through the center of the test piece and extends along the direction of the step.
This crease is formed by processing a test piece having the above dimensions according to the following procedure.
-Procedure de: The examiner manually folds the test piece having the above dimensions at the fold position.
-Procedure df: Place the test piece created in procedure de on a flat surface and crimp the following at the crease.
Apply the device and press the crimping device at the crease at a speed of about 10 [mm / s].
Restore. After that, the temperature is 23 [° C.] and the temperature is 23 [° C.] in accordance with JIS Z0203.
The test piece is left for 24 hours under a temperature and humidity condition of 50 [%] and humidity.
> Crimping equipment: Product name "Tape crimping roller (manual)", manufactured by Yasuda Seiki Seisakusho, product number
No. 349, roller mass: 1 [kg]
-Procedure deg: After opening the crease of the test piece (with crease) left in procedure df, the above hand
The burst strength is measured in the order of dc and dd.

--Evaluation--
With respect to the measured corrugated cardboard materials of Examples d10 to d24 and Comparative Examples d25 and d26, the easiness of tearing of the test piece without creases, the easiness of tearing of the test piece with creases, and the rule-breaking property were determined. evaluated.
"Easy to tear" is housed in the same box as "Easy to tear" described above, except that "Easy to tear without creases" and "Easy to tear with creases" are evaluated respectively. It is an evaluation standard corresponding to the light weight of the load capacity for the contents.

The above-mentioned "easiness of tearing without creases" and "easiness of tearing with creases" were evaluated by the following procedures dD to dI. The measured corrugated cardboard material to be evaluated was evaluated in accordance with JIS P8111: 1989 standard.
-Procedure dD: The size of each side is 1 [cm] made of iron at each of the following positions on the bottom of the evaluation box.
Cube (Artec Co., Ltd., product name "Density measurement body (cube)",
Part number: 61-6020-211, model number: 8350) is placed. In addition, standing
The square is an adhesive at each position on the bottom (product name "Aron" manufactured by Toagosei Co., Ltd.
It is attached using "Alpha EXTRA impact resistance").
> Position: At the four corners of the bottom surface 30 of the evaluation box (see FIGS. 3 and 4), from the vertical end to the vertical
80 [mm] toward the center of the direction and laterally from the end in the lateral direction
With reference to the position of 50 [mm] toward the center (see the broken line in FIG. 3).
4, 4 [pieces] of cubes 31 (see FIGS. 3 and 4) are arranged.
> Dimensions of the bottom surface 30 of the evaluation box: length 210 [mm]
Horizontal 297 [mm]
The evaluation box was an assembly type (IFC code 0401) so as not to be affected by the tape.

-Procedure dE: An evaluation box in which 4 [pieces] cubes are arranged on the bottom surface 30 in the procedure dD is placed on the pedestal 32.
(See Fig. 4). The pedestal 32 (see FIG. 4) is a cube in top view.
Cube 31 (FIG. 4) overlaps with each of 31 (see FIGS. 3 and 4).
Space 33 (see Fig. 4) that communicates with the outside with dimensions that allow entry (see Fig. 4)
) Is provided.
-Procedure dF: Below the upper side of 4 [pieces] of cubes placed on the bottom surface 30 of the evaluation box in step dD.
The stainless steel vat 34 (see FIGS. 3 and 4) described above is placed.
> Bat ("SUS Bat"): (TRUSCO NAKAYAMA Co., Ltd., product name "Stainless Steel"
Deep assembly bat No. 5, product number: T-FU-7, bottom support
Is "230 [mm] x 150 [mm]")

-Procedure dG: The weight per unit area is 15 [k] on the SUS bat arranged in the procedure dF.
Gf / cm ² ], let the weight 35 (see FIGS. 3 and 4) stand still.
Leave it for 1 [hour]. Weight 35 (see FIGS. 3 and 4) has 4 [pieces].
SUS bat 34 (Fig.) So that the load is evenly applied to each of the cubes.
3. Place it in the center of Fig. 4).
-Procedure dH: Visually confirm whether or not the evaluation box has been torn in the procedure dG under each weight condition.
Admit. Whether or not a tear has occurred is specifically determined by the cube on the bottom of the evaluation box.
Judge by whether or not it has penetrated.
-Procedure dI: Weight per unit area in procedure dG is 10 [kgf / cm ² ], 5 [kg
Change the weight so that it becomes f / cm ² ], and follow the procedure dD under each weight condition.
A test of ~ dH was also performed.

As described above, the evaluation according to the procedures dD to dI is 15 [kgf / cm ² ], 10 [kgf / cm ² ] and 5 for the measured corrugated cardboard materials of Examples d10 to d24 and Comparative Examples d25 and d26, respectively. Under the three weight conditions of [kgf / cm ² ], the evaluation of "easiness of tearing without creases" and the evaluation of "easiness of tearing with creases" are carried out respectively. The evaluation of "easiness of tearing without creases" is an evaluation in which an iron cube is placed on the bottom surface of the evaluation box where no creases are provided. The evaluation of "easiness of tearing with creases" is an evaluation in which a cube is arranged at a place where a crease is provided on the bottom surface of the evaluation box.

"Easy to tear without creases" and "Easy to tear with creases" were evaluated according to the following criteria.
・ ◎: No tearing occurs under any of the three weight conditions.
-○: 1 [location] or more is torn under the condition of 15 [kgf / cm ² ].
-A tear of 1 [location] or more occurs under each condition of Δ: 15,10 [kgf / cm ² ] (word).
In other words, at 10 [kgf / cm ² ], more than 1 [location] is torn, but 5 [
There is no tear at kgf / cm ² ]).
-X: One or more tears occur in any of the three weight conditions.
Of the above evaluations, those with "Δ" or higher were regarded as good evaluations. In the above criteria, the weight condition of 5 [kgf / cm ² ] is set as the criterion for evaluating "△" or more, so the weight of luggage (5 [kg]) that is often transported in the mail-order field is taken into consideration. The evaluation is carried out. In addition, since the weight condition of 15 [kgf / cm ² ] is set as the criterion for evaluating "◎", the weight upper limit (15 [kg]) of luggage that is common in the automatic box making system (fully automatic machine). ) Is taken into consideration.

"Rule splitting property" is an evaluation standard corresponding to the resistance to damage when the measured corrugated cardboard material is bent. Damage includes cracking, tearing, and tearing of the liner at the creases. The crease portion is an area including the periphery of the fold.
The evaluation of the crease property was carried out by visually confirming whether or not the liner located outside the crease at the crease was crease in all the creases of the measured corrugated cardboard material. ..
The confirmation results were evaluated according to the following two criteria.
・ ○: No cracks were found in all the creases.
・ ×: One or more ruled cracks were found in the creases.
Of the above evaluations, "○" was regarded as a good evaluation and "×" was regarded as a poor evaluation.

In Examples d10 to d24, both the burst strength with creases and the burst strength without creases are 500 [kPa] or more, and "easiness of tearing without creases" and "breakage with creases" All of "ease" were evaluated as "△" or higher.
In Examples d11 to d13 and d15 to d24 having a crease-bearing burst strength of 650 [kPa] or more, the crease-bearing easiness of tearing was evaluated as “◯” or higher. In Examples d11 to d21, d23, and d24 having a crease-free rupture strength of 650 [kPa] or more, the crease-free tearability was evaluated as “◯” or higher.
In Examples d18, d21, d23, and d24 having a crease-bearing burst strength of 1500 [kPa] or more, an evaluation of “⊚” was obtained for the crease-bearing easiness of tearing. In Examples d12, d23, and d24 having a crease-free burst strength of 1500 [kPa] or more, an evaluation of “⊚” was obtained for the crease-free tearability.

On the other hand, in Comparative Examples d25 and 26 in which at least one of the crease-free burst strength and the crease-bearing burst strength is less than 500 [kPa], the crease-free rupture easiness and the crease-bearing rupture easiness at least. One of them was evaluated as "x".
Specifically, in Comparative Example d25 of a single flute, both the burst strength without creases and the burst strength with creases were less than 500 [kPa], and both the crease-free and crease-bearing tearability were indicated by "x". Was obtained. In the double flute comparative example d26, the rupture strength with creases was 500 [kPa] or more, and the fragility with creases was evaluated as “△”, but the rupture strength without creases was 500. When it was less than [kPa], the evaluation of "x" was obtained for the ease of tearing without creases.

In Examples d10 to d22 of Examples d10 to d24, both the burst strength with creases and the burst strength without creases are 2000 [kPa] or less, and the "rule-breaking property" is "○". Was obtained.
In Examples d23 and d24 in which at least one of the crease-bearing burst strength and the crease-free burst strength is greater than 2000 [kPa] among the examples d10 to d24, the evaluation of “x” in the rule-breaking property is evaluated. Obtained.

In view of Comparative Example d25 of Single Flute, from Examples d10 to d17 and d23 of Single Flute, if the burst strength of the single flute with creases is 500 [kPa] or more, the contents fall out from the evaluation box. It can be said that this can be prevented. Further, if the burst strength with creases is 650 [kPa] or more, it can be said that damage to the evaluation box due to the load of the contents can be suppressed. Moreover, if the burst strength is 1500 [kPa] or more, it can be said that damage to the evaluation box due to the load of the contents can be prevented.
On the other hand, in view of Example d23 of the single flute, from Examples d10 to d17 of the single flute, if the burst strength of the single flute with creases is 1500 [kPa] or less, all the folds of the measured corrugated cardboard material. It can be said that damage can be prevented.

In addition, it can be seen that the larger the basis weight and density of the liner base paper, the higher the burst strength. From such a correlation between the basis weight and the burst strength, if the basis weight of the liner base paper is 80 [g / m ² ] or more and the density is 0.75 [g / cm ³ ] or more in the single flute, it is evaluated. It can be said that it is possible to prevent the contents from falling out of the box. Furthermore, in the case of a single flute, if the basis weight of the liner base paper is 160 [g / m ² ] or more and the density is 0.85 [g / cm ³ ] or more, damage to the evaluation box due to the load of the contents should be suppressed. Can be said to be possible. In addition, for single flutes, if the basis weight of the liner base paper is 240 [g / m ² ] or more and the density is 0.87 [g / cm ³ ] or more, damage to the evaluation box due to the load of the contents should be prevented. Can be said to be possible.

Further, among Examples d10 to d17 and d23 of the single flute, from Examples d13 and d14 in which the material and density of the liner base paper are different, in the single flute, the pulp of the surface layer is specifically due to the difference in the material of the liner base paper. It is presumed that the greater the proportion of softwood kraft pulp contained in, the lower the burst strength tends to be. Further, among Examples d10, d17, and d23 of the single flute, from Examples d15, d16, and d17 in which the base paper is common and only the flute is different from each other, the difference in the flute is no crease and crease is present in the single flute. It is presumed that it does not affect the burst strength.

From Examples d10 to d17, d23 and Comparative Example d25 of the single flute, it can be seen that the single flute tends to have a lower burst strength with creases than the burst strength without creases.
From Examples d10 in which the liner basis weight is relatively small and Examples d11 and d12 in which the liner basis weight is relatively large, the single flute measurement using the liner having a relatively small basis weight is compared with no crease. The burst strength with creases does not change significantly, whereas the single flute measurement cardboard material using a liner with a relatively large basis weight has creases compared to the burst strength without creases. It can be seen that the degree of decrease in burst strength is large.

In view of Comparative Example d26 of the double flute, from Examples d18 to d22 and d24 of the double flute, the burst strength without creases is 500 [kPa] or more and the burst strength with creases is 520 [kPa]. With the above, it can be said that it is possible to prevent the contents from falling out of the evaluation box. Further, from Examples d18 to d21 and d24, if the burst strength without creases is 700 [kPa] or more and the burst strength with creases is 800 [kPa] or more, the evaluation box based on the load of the contents It can be said that the damage of the box can be suppressed. Moreover, from Examples d18, d21, and d24, if the burst strength without creases is 1000 [kPa] or more and the burst strength with creases is 1500 [kPa] or more, the evaluation box based on the load of the contents It can be said that the damage can be prevented.
On the other hand, in view of Example d24 of the double flute, from Examples d18 to d22 of the double flute, if the burst strength of the double flute without creases and with creases is 2500 [kPa] or less, the corrugated cardboard material is measured. It can be said that damage can be prevented at all folds.

From Examples d18 to d22, d24 and Comparative Example d26 of the double flute, it can be seen that in the double flute, the rupture strength with creases tends to be higher than the rupture strength without creases. Double flute measurement In corrugated cardboard materials, when the creases are unfolded, the steps of the core are crushed by the folds, so the distance between the two liners and the three cores in the thickness direction is close. It is presumed that the burst strength with creases is higher than that without creases because the steps of the core are crushed and overlap in the thickness direction.

In addition, even with double flutes, it can be seen that the greater the basis weight and density of the liner base paper and core base paper, the higher the burst strength. From such a correlation between the basis weight and the burst strength, in the double flute, the basis weight of the liner base paper is 80 [g / m ² ] or more and the density is 0.75 [g / cm ³ ] or more, or If the basis weight of the core base paper is 130 [g / m ² ] or more and the density is 0.65 [g / cm ³ ] or more, it can be said that it is possible to prevent the contents from falling out of the evaluation box. .. In particular, if the basis weight of the liner base paper is 80 [g / m ² ] or more and the density is 0.75 [g / cm ³ ] or more, damage to the evaluation box due to the load of the contents can be suppressed. I can say. Moreover, if the basis weight of the liner base paper is 150 [g / m ² ] or more and the density is 0.85 [g / cm ³ ] or more, damage to the evaluation box due to the load of the contents can be prevented. I can say.

<Structure e>
--Measurement target--
For Examples e1 to e3 and Comparative Example e4 regarding the configuration e, the same base papers as those of Examples b1 to b3, c1 to c3, d1 to d3 and Comparative Examples b4, c4 and d4 are used, and Examples c1 to c3 and d1 are used. A corrugated cardboard material for measuring A flute produced using a corrugator having the same stepping rolls as in ~ d3 and Comparative Examples c4 and d4 was used.
The adhesive strength was measured for each of Examples e1 to e3 and Comparative Example e4 using the measured corrugated cardboard material produced as described above, and the adhesive strength shown in Table 10 below was measured.
Regarding the notation in Table 10, "S side" means "single facer side" (back liner side), and "G side" means "glue machine side" (front liner side).

The "adhesive force" is a parameter corresponding to the peeling resistance value of the adhesive portion between the stepped top of the core (the part corresponding to the maximum value) and the liner in the sheet of the measured corrugated cardboard material. To put it plainly, it is a parameter corresponding to the difficulty of peeling off the liner forming the sheet of the corrugated cardboard material.
This adhesive force was measured by the following procedures ea to ed.
-Procedure ea: Seas for 10 upper and lower stages based on half the total number of stages of the measured corrugated cardboard material
Twenty sheets without deformation (for example, dents) are cut out.
-Procedure eb: From the sheet cut out in step ea, the test sun to the size shown below
Cut out the pull with a cutter.
Direction parallel to the corrugated structure of the core (vertical direction <CD direction>): 50 [mm]
Direction orthogonal to the corrugated structure of the core (horizontal direction <MD direction>): 85 [mm]
-Procedure ec: Prepare ten samples on the front and back of the sample cut out in procedure eb. Ingredients
Physically, ten sheets for measuring the adhesive strength on the single facer side and a guru
-Prepare 10 sheets to measure the adhesive strength on the machine side.
-Procedure ed: The sample prepared in procedure ec is attached to the following measuring device and conforms to the following.
Adhesive strength was measured according to standards and measurement conditions.
> Compliant standard: JIS Z0402
> Measuring device: Compression tester (manufactured by A & D Co., Ltd., RTF1350)
> Measurement conditions: Pin attachment (Nippon TMC Co., Ltd.) is attached to the sample.
Then, place it on the measuring device and place it on the measuring device so that the peeling surface is on the upper side, 13 [mm / min.
], And the maximum load when the adhesive part of the sample is peeled off.
Measure the weight.
-Procedure ee: Adhesive strength measured in procedure ed, similar to procedure ad, aD, bg, dd.
Exclude numerical values that can cause disturbances (factors) that reduce the accuracy of measurement results.
The average value was taken as the burst strength.

--Evaluation--
The liner peeling was evaluated for Examples e1 to e3 and Comparative Example e4 in which the adhesive strength was obtained as described above.
"Liner peeling" is an evaluation standard corresponding to the quality of the box and the quality of the appearance. This liner peeling was evaluated by the following procedures eA to eC.
-Procedure eA: Straddle the crease of the measured corrugated cardboard material as in the evaluation of the box-making property of the configurations a and b
Cut out the evaluation cardboard piece with the cut line. In addition, the first evaluation Dan
When cutting out a ball piece, replace it with a new cutter blade, and this cutter blade
Was used without replacement until the 100th (last).
-Procedure eB: Assemble the evaluation cardboard pieces cut out in procedure eA by hand.
-Procedure eC: Peeling of the liner (sheet) in the evaluation box assembled in step eB
Observe the presence or absence.

The above liner peeling was evaluated according to the following criteria.
-⊚: No peeling of the liner was observed in all (100 [box]) evaluation boxes.
-○: Liner peeling was observed in 1 to 2 [boxes] of the evaluation boxes of 100 [boxes].
-△: The liner was peeled off in 3 to 4 [boxes] out of the evaluation boxes of 100 [boxes].
-X: Liner peeling was observed in 5 [boxes] of the 100 [boxes] evaluation boxes.
Regarding Examples e2 and e3 in which the evaluation of "○" was obtained for liner peeling, liner peeling was observed in 1 [box] in Example e2, and liner peeling was observed in 2 [box] in Comparative Example e3. It was observed. In addition, there were no examples or comparative examples in which a rating of "Δ" was obtained for liner peeling.

In Examples e1 to e3, the average value of the adhesive strength measured on the single facer side and the glue machine side (hereinafter referred to as "average adhesive strength") is 140 [N] or more, and the liner peeling is "○". The above evaluation was obtained. In particular, in Example e1 having an average adhesive strength of 220 [N] or more, an evaluation of “⊚” was obtained.
On the other hand, in Comparative Example 1 in which the average adhesive strength was less than 140 [N], an evaluation of "x" was obtained for the liner peeling.

If the above average adhesive strength is 140 [N] or more, the liner will not easily come off when the evaluation cardboard piece is cut out from the measurement cardboard material, and the liner will not come off easily when the evaluation box is assembled from the evaluation cardboard piece. Inferred. Furthermore, if the average adhesive strength is 220 [N] or more, it is presumed that the liner can be prevented from peeling off both when cutting out and assembling the evaluation cardboard piece. Therefore, the average adhesive strength is 140 [N]. With the above, it can be said that the liner of the evaluation box is less likely to come off. As a result, it can be said that the deterioration of the appearance of the evaluation box can be suppressed and the quality of the evaluation box can be ensured.

[3. Example of combining the three configurations]
Finally, an embodiment ade in which a part of the configuration a, d and e are combined will be described.
The details of the measurement target and evaluation of Example ade are the same as those described above unless otherwise specified.
--Measurement target--
Example ade was evaluated for a measurement corrugated cardboard material having the parameters listed below.
-Thickness dimension: 5.1 [mm]
-Rupture strength: 2009 [kpa]
-Average adhesive strength: 237.5 [N]
> Single facer side: 230 [N]
> Glue machine side: 245 [N]

--Evaluation--
Measurement of Example ade The corrugated cardboard material was evaluated for cracking, easiness of tearing, and liner peeling. As a result, excellent evaluation (“◎” mentioned above) was obtained in all of the rule cracking, the easiness of tearing, and the liner peeling.
From the evaluation results of Example ade, it can be seen that when a part of the configuration a, d, and e are combined, the evaluation corresponding to the part, d, and e of each configuration a is not impaired and is excellent.

Further, when the measured corrugated cardboard material having the above parameters is used in the box making system, it is presumed that the safety of manual work for the measured corrugated cardboard material is improved. The reasons for this include the following reasons α and β.
・ Reason α: For the corrugated cardboard material to be measured because a good evaluation of liner peeling can be obtained.
In addition to preventing the liner from unintentionally peeling off during manual work,
When an appropriate force is applied in the manual work to break the corrugated cardboard material
It is inferred that the ina will come off. In other words, the average adhesive strength is excessive
Then, there is room for improvement in safety during breaking work.
・ Reason β: If the sheet of corrugated cardboard material to be measured is excessively thin, work with the edge of the sheet.
There is room for improvement in safety when in contact with personnel. Measurement cardboard material
If the seat is too thick, it is safe for the liner of the seat to come into contact with the worker.
There is room for improvement in sex. On the other hand, in Example ade, the rule cracking is excellent.
Since a good evaluation is obtained, the edge of the sheet and the liner come into contact with the worker.
It is presumed that the safety will be improved.

[III. Modification example]
The above-described embodiment is merely an example, and there is no intention of excluding the application of various modifications and techniques not specified in this embodiment. Each configuration of the present embodiment can be variously modified and implemented without departing from the gist thereof. In addition, it can be selected as needed and can be combined as appropriate.
For example, when the corrugated cardboard material is a material for a box-making system, it is preferable that no additional processing such as intentionally formed cuts or perforations is applied to the surface layer of the liner in the corrugated cardboard material. It is preferable that the crease is a portion where the ruled line to be provided is folded back by 180 [°] from the starting point (for example, the ruled line is inside). On the other hand, when the corrugated cardboard material is a material other than that used for the box making system, processing such as cuts and perforations may be performed.

The use of the bellows-folded corrugated cardboard material described above is not limited to the use as a box-making material applied to a box-making system.
There are various ways to utilize the bellows-folded corrugated cardboard material, which is different from the conventional single-wafered corrugated cardboard sheet, and makes use of the structure in which a plurality of sheets are continuously provided through folds.
For example, the bellows-folded corrugated cardboard material can be treated as a web-like paper material having a large dimension in the extending direction in the unfolded state of the sheet.

As a method of using it as a web-like paper material, for example, the following uses can be mentioned as an example.
Use as a disaster product: By attaching it to a window, it can be used to prevent window cracking during a typhoon.
In addition, privacy protection and stress reduction at evacuation shelters
Use as a reduction partition, cushioning material and cold
It can be used as a rug for countermeasures.
Use at event events: Can be used for creative works such as signboards for events and school events
To.
Use as a building / moving material: Temporarily open doors, walls, doors, etc. at construction sites and moving sites
If you need to protect it, stick it on the object
It can be used as a protective material (curing material). Wrap around the object
Can be used as a protective material (packing material) to be attached
You can also do it.
In any of the usage methods, since the structure is such that a plurality of sheets are continuously provided through folds, there are advantages that work efficiency can be improved and dimensions in the extending direction can be secured.

[IV. Addendum]
Regarding the above embodiments, the additional notes regarding the burst strength of the corrugated cardboard material are disclosed.
[Appendix 1]
In a continuous double-flute double-sided cardboard, a rectangular sheet is folded back in a second direction orthogonal to the first direction on a plane along the fold at each of the folds extending linearly along the first direction. , A bellows-folded corrugated cardboard material in which the sheets are stacked along a third direction orthogonal to both the first direction and the second direction.
The sheet is
In a normal state where pretreatment is performed for 24 hours or more under temperature and humidity conditions of temperature 23 [° C.] and humidity 50 [%] in accordance with JIS Z0203.
A corrugated cardboard material having a burst strength of 520 [kPa] or more and 2500 [kPa] or less at a portion including the crease measured in accordance with JIS P8131.
[Appendix 2]
The sheet is
The basis weight of the liner base paper is 90 [g / m ² ] or more and 280 [g / m ² ] or less.
The basis weight of the core base paper is 90 [g / m ² ] or more and 170 [g / m ² ] or less.
The corrugated cardboard material according to Appendix 1, wherein the burst strength of the portion not including the crease measured in accordance with JIS P8131 is 500 [kPa] or more and 2500 [kPa] or less.
[Appendix 3]
The corrugated cardboard material according to Appendix 1 or 2, wherein the sheet is an AB flute.
[Appendix 4]
In a continuous double-flute double-sided cardboard, a rectangular sheet is folded back in a second direction orthogonal to the first direction on a plane along the fold at each of the folds extending linearly along the first direction. , A bellows-folded corrugated cardboard material in which the sheets are stacked along a third direction orthogonal to both the first direction and the second direction.
The sheet is
In a normal state where pretreatment is performed for 24 hours or more under temperature and humidity conditions of temperature 23 [° C.] and humidity 50 [%] in accordance with JIS Z0203.
The burst strength of the portion not including the crease measured in accordance with JIS P8131 is 500 [kPa] or more.
A corrugated cardboard material having a burst strength of 520 [kPa] or more at a portion including the crease measured in accordance with JIS P8131.
[Appendix 5]
The corrugated cardboard material according to Appendix 4, wherein the burst strength of the portion not including the crease and the burst strength of the portion including the crease are 2500 [kPa] or less.
[Appendix 6]
The corrugated cardboard material according to Appendix 4 or 5, wherein the sheet has an average value of adhesive force of 140 [N] or more measured on the single facer side and the glue machine side in accordance with JIS Z0402.
[Appendix 7]
The sheet is
The step-by-step rate is 1.2 [times] or more and 1.7 [times] or less.
The corrugated cardboard material according to any one of Appendix 4 to 6, wherein the planar compressive strength measured in accordance with JIS Z0403-1 is 50 [kPa] or more and 250 [kPa] or less. ..
[Appendix 8]
The sheet is provided with the core at two locations where the core intersects and is adjacent to the virtual auxiliary line extending in the second direction at the center of the front liner and the back liner when viewed from the first direction. The cardboard material according to any one of Supplementary note 4 to 7, wherein the ratio obtained by dividing the difference between the two acute angles formed by the auxiliary line by the sum of the two acute angles is 0.30 or less.
[Appendix 9]
A corrugated cardboard box using the corrugated cardboard material according to any one of Items 1 to 8.

1 Cardboard material 10th stage (wave)
2 Sheets 20 Sheets vs. 21 1st Sheet 22 2nd Sheet 23 3rd Sheet F Fold L Auxiliary Line L1 Vertical Dimension (1st Dimension)
L2 horizontal dimension (second dimension)
L3 height dimension (third dimension)

Claims (4)

In a continuous double-flute double-sided cardboard, a rectangular sheet is folded back in a second direction orthogonal to the first direction on a plane along the fold at each of the folds extending linearly along the first direction. , A bellows-folded corrugated cardboard material in which the sheets are stacked along a third direction orthogonal to both the first direction and the second direction.
The sheet is
Under normal conditions where pretreatment was performed for 24 hours or more under temperature and humidity conditions of temperature 23 [° C.] and humidity 50 [%] in accordance with JIS Z0203.
A corrugated cardboard material having a burst strength of 520 [kPa] or more and 2500 [kPa] or less at a portion including the crease measured in accordance with JIS P8131. The sheet is
The basis weight of the liner base paper is 90 [g / m ² ] or more and 280 [g / m ² ] or less.
The basis weight of the core base paper is 90 [g / m ² ] or more and 170 [g / m ² ] or less.
The corrugated cardboard material according to claim 1, wherein the burst strength of the portion not including the crease measured in accordance with JIS P8131 is 500 [kPa] or more and 2500 [kPa] or less. The cardboard material according to claim 1 or 2, wherein the sheet is an AB flute. A cardboard box using the cardboard material according to any one of claims 1 to 3.

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