JP6741181B1 - Cardboard material and cardboard box using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cardboard material in which breakage of a fold of a corrugated cardboard material is suppressed, and a cardboard box using the same. A corrugated cardboard material (1) is folded back in a second direction (MD) at each of folds (F) in which a rectangular sheet (2) linearly extends along a first direction (CD) in a continuous double-sided corrugated cardboard. Sheets 2 are stacked along the TD. In this cardboard material 1, the basis weight of the liner constituting the double-sided cardboard is 110 [g/m2] or more and 290 [g/m2] or less, and the liner pulp fiber length is 0.55 [mm] or more. It is 1.60 [mm] or less. Further, the fiber orientation ratio, which is the ratio of the orientation of the pulp fiber of the liner in the second direction MD to the orientation of the first direction CD, is 1.0 or more and 2.0 or less, and the fiber core of the double-sided cardboard is The fiber length ratio, which is the ratio of the pulp fiber length of the liner base paper to the pulp fiber length, is 0.65 or more and 1.90 or less. [Selection diagram] Figure 1

Description

TECHNICAL FIELD The present invention relates to a corrugated cardboard material and a cardboard box using the same.

As a material for box making, a corrugated cardboard material (also called "fanfold") is known. The cardboard material is provided with folds between continuous rectangular sheets, and the sheets are alternately folded back at the folds. In such a corrugated cardboard material, continuous sheets are vertically stacked and folded into a rectangular parallelepiped shape.

The above corrugated board material is a box-making system that manufactures boxes of the optimum size according to the size of the packaging target (“automatic packaging system”, “three-side variable system”, “three-side automatic packaging”, “on-demand packaging”). It is also used as a packaging material. In this box making system, various steps exemplified below are carried out.
-Feeding process: a process of feeding the corrugated cardboard material-Cut process: a process of cutting the flat cardboard material fed out in the feeding process-Folding process: a process of assembling a box from the cardboard material cut out in the cutting process-Printing process : Printing on a flat or assembled cardboard material ・Packing process: A process of storing contents in a box to be assembled

Special table 2013-513869 gazette

However, the fold may be damaged depending on the properties used for the corrugated cardboard material.
This case was created in view of the above problems, and one of its purposes is to prevent breakage of folds. It should be noted that the present invention is not limited to this purpose, and it is also possible to achieve actions and effects that cannot be obtained by the conventional technique, which are actions and effects derived from the respective configurations shown in "Modes for carrying out the invention" described later. It can be positioned for other purposes.

The corrugated cardboard disclosed herein is a continuous double-sided corrugated cardboard in which each rectangular fold in which a rectangular sheet extends linearly along the first direction is a plane orthogonal to the first direction on a plane along the fold. The corrugated cardboard material is folded in two directions, and the sheets are stacked along a third direction orthogonal to both the first direction and the second direction.
In this cardboard material, the basis weight of the liner constituting the double-sided cardboard is 110 [g/m ² ] or more and 290 [g/m ² ] or less, and the pulp fiber length of the liner is 0.55 [mm ] And 1.60 [mm] or less, and the fiber orientation ratio, which is the ratio of the orientation of the pulp fibers in the liner in the second direction to the orientation in the second direction, is 1.0 or more and 2 The fiber length ratio, which is a ratio of the pulp fiber length of the liner to the pulp fiber length of the core forming the double-sided cardboard, is 0.65 or more and 1.90 or less.

According to this case, breakage of the fold can be suppressed.

It is a perspective view showing a corrugated cardboard material. It is a schematic diagram which shows an example of the step in the sheet|seat used for the corrugated cardboard material of the bellows fold.

Hereinafter, a cardboard material and a cardboard box as an embodiment 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 a continuous corrugated cardboard. A double-sided cardboard having liners on both sides of the core is used as the cardboard material.

The double-sided corrugated cardboard is a single-flute corrugated cardboard consisting of three base papers (materials) corresponding to one core and two liners, as well as so-called "double-sided corrugated cardboard" and "multi-sided double-sided cardboard". As described above, a multi-flute cardboard including two or more cores and two liners and five or more base papers corresponding to one or more center liners, respectively, is also included. In this embodiment, a cardboard material made of a single-flute double-sided cardboard is mainly exemplified.

When the cardboard material is made into a box, it becomes a cardboard box. More specifically, the corrugated cardboard used in 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 into a box development pattern, and a box shape. It is made into a cardboard box through various processes such as a fold process of standing up. The box-making system for assembling the cardboard box is not particularly limited, but for example, "CMC Carton Wrap XL", "CMC Carton Wrap 1000", "Neopost", which is a fully automatic system of an automatic packaging system. CVP-500", "TXP-600 manufactured by OS Machinery Co., Ltd.", semi-automatic system "EM7 manufactured by Pack Size", and "Compack manufactured by Panotec" can be used.

In the present embodiment, an example in which the following directions I and II correspond as shown in Table 1 below is given, and the cardboard material is assumed to be placed on a horizontal surface.
-Direction I: Direction in a cardboard material placed on a horizontal surface-Direction II: Direction in a semi-finished product in the process of manufacturing the cardboard material

The longitudinal direction (first direction, referred to as "CD" in the drawing) and the lateral direction (second direction, referred to as "MD" in the drawing) are horizontal directions, and along the sheet (fold). The direction in which the plane extends. The vertical direction and the horizontal direction are orthogonal to each other. The height direction (third direction, referred to as "TD" in the drawing) 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 stacked.

The MD (Machine Direction) direction is also referred to as “flow direction”, and is the direction in which the corrugated board manufacturing process progresses from upstream to downstream. The CD (Cross Direction) direction is a direction orthogonal to the MD direction on 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 the present embodiment means a range of the numerical value X or more and the numerical value Y or less.

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

[1. Folded structure]
As shown in FIG. 1, the cardboard material 1 is a box-shaped material having a rectangular parallelepiped shape.
In the corrugated cardboard material 1, a continuous rectangular sheet 2 (only a part of which is marked in FIG. 1) is folded at a fold F (a part of which is marked in FIG. 1), and the folded sheet 2 is Stacked in the height direction.
In the corrugated cardboard material 1 thus folded, a plurality of folds F linearly extend in 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 continuous sheets 2 (shown by a chain double-dashed line in FIG. 1).
First sheet 21: Sheet 2 continuous to one side of second sheet 22
Second sheet 22: Sheet 2 that is continuous with both the first sheet 21 and the third sheet 23
-Third sheet 23: Sheet 2 continuous to the other side of second sheet 22

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

In the first sheet 21, the corrugated cardboard steps 10 (at the front end edge in FIG. 1 are designated by reference numerals only) E ₁ extending in the lateral direction (the direction intersecting the fold F) ( The ripples) are exposed. Similarly, the second sheet 22 has a second edge E ₂ extending in the lateral direction (direction intersecting the fold F) (corresponding only to the front edge in FIG. 1 with reference numeral) of the cardboard. The step 10 is exposed.
In the sheet pair 20 including 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 cardboard sheet 2 having a higher strength than a material that can be wound into a roll can be made into a compact packing form. The corrugated cardboard material 1 in which the sheet 2 of which strength is ensured is folded is suitable for use as a packaging material of a box making system for manufacturing a box requiring strength.

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

[2. Parameter]
The parameters of the cardboard material 1 will be described below.
First, basic parameters such as the size and the number of steps of the cardboard material 1 will be described. After that, parameters relating to the properties of the cardboard material 1 will be described in detail.

[2-1. Basic parameters]
The size of the cardboard material 1 is determined by the following dimensions L1 to L3.
・Longitudinal dimension L1: Vertical dimension (first dimension)
・Horizontal dimension L2: Lateral dimension (second dimension)
・Height dimension L3: Height dimension (third dimension)
As the dimensions L1 to L3 are smaller, the size and shape of the box to be manufactured may be more restricted, and as the dimensions L1 to L3 are larger, workability such as transportation and delivery may be reduced. 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 cardboard material 1 is N [pieces], the number of sheets 2 is N+1 [pieces]. In this case, N+1 sheets of sheets 2 are superposed on the cardboard material 1.
For example, as the number of steps of the cardboard material 1, for example, various numbers of steps of 10 to 1000 [steps] can be mentioned. With respect to the corrugated cardboard material for which the parameters relating to folding, the details of which will be described later, are measured, it is preferable to measure the parameters for each of all the steps for measurement objects having a predetermined number of steps (eg, 100 [steps]). On the other hand, for a measurement target having a predetermined number of steps (for example, 100 [steps]) or more, the parameter may be measured partially (for example, a part divided into parts or a set area).

The sheet 2 used for the cardboard material 1 can have an arbitrary basis weight. The range of the grammage adopted for the sheet 2 is 50 to 1500 [g/m ² ], preferably 100 to 1000 [g/m ² ] and more preferably 200 to 1000 [g/m ² ]. The range is 800 [g/m ² ] and more preferably the range is 200 to 600 [g/m ² ].
The weight of the corrugated cardboard material 1 is calculated by multiplying the above basis weight by taking into account the step reproducibility of the core and multiplying the vertical dimension L1 and the horizontal dimension L2 by the number N+1 of steps of the sheet 2.

[2-2. Properties parameters]
This embodiment is based on the viewpoint that a good box can be manufactured when it is used as a material for a box making system, and has a configuration relating to the properties of the cardboard material 1. Specifically, it is based on at least one of viewpoints I to V listed below, and has a predetermined configuration relating to the properties of the cardboard material 1.
-Aspect I: Ensuring box-making ability-Aspect II: Suppressing breakage of the folded portion when assembling into a box-Aspect III: Ensuring aptitude when printing is performed-Aspect IV: Suppressing damage to fold F ・Point of view V: Suppressing liner peeling

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.
-Issue I: Insufficient box-making property-Issue II: Fracture and squeeze of the folded parts when assembling into a box-Issue III: Inadequacy when printed -Problem IV: Damage to fold F is easy to occur-Problem V: Liner is likely to be peeled off

The predetermined configurations corresponding to the viewpoints I to V and the tasks I to V include at least one of the following configurations a to e.
-Structure a: Structures 1 and 2 below
>Structure 1: Thickness dimension is within a predetermined size range> Structure 2: Plane compressive strength is within a predetermined compressive strength range Structure b: Structures 2 and 3 below
>Configuration 2: Configuration 2 above
>Structure 3: Step repeat ratio is within a predetermined magnification range. Structure c: Angle ratio is within a predetermined ratio range. Structure d: Structures 4 to 7 below.
>Structure 4: The basis weight of the liner is within a predetermined basis weight range> Structure 5: The pulp fiber length of the liner is within a predetermined fiber length range> Composition 6: The fiber orientation ratio of the liner is within a predetermined orientation ratio range >Structure 7: Fiber length ratio is within a predetermined fiber length ratio range. Structure e: Adhesive force is within a predetermined force range.

<Structure a>
As described above, the configuration a includes the “configuration 1 in which the thickness dimension is within a predetermined size range” and the “configuration 2 in which the plane compression strength is within a predetermined compression strength range”.
The “thickness dimension” of the configuration a is a parameter indicating the thickness of each sheet 2. 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 crush resistance of the sheet of measured cardboard material.

The inventors of the present application have found that the above problems I and II tend to be suppressed when the thickness dimension of the sheet 2 is within a predetermined size range and the plane compression strength is within a predetermined compression strength range. Got Conversely, it has been found that the sheet 2 having the thickness dimension and the plane compressive strength outside the range of the configuration a tends to cause the problems I and II.
That is, the seat 2 is provided with the configuration a based on the viewpoints I and II described above.

If the thickness dimension exceeds the predetermined dimension range, it is conjectured that when the sheet 2 is bent along the ruled line for box making, the liners 2a and 2b are not fully extended and are broken, which causes Problem II. On the other hand, if the thickness dimension is below the predetermined dimension range, the strength of the sheet 2 is insufficient, and it is presumed that the sheet I is bent at a place other than the ruled line for box making and causes the problem I. Even when the plane compressive strength is below the predetermined compressive strength range, the strength of the sheet 2 is insufficient, and it is presumed that the sheet 2 is bent at a place other than the ruled line for box making, which causes the problem I. It
Further, if the plane compression strength exceeds the predetermined compression strength range, it is presumed that the ruled line for box making is difficult to be formed, 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 not less than 4.0 [mm] and not more than 7.0 [mm].
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 preferably 110 [kPa] or more and 190 [kPa] or less.

<Structure b>
The configuration b includes the same “configuration 2 in which the plane compression strength is within a predetermined compression strength range” as in the configuration a, and the above-described “configuration 3 in which the stage repeat ratio is within a predetermined magnification range”.
The “step take-up rate” of the configuration b is a parameter indicating the magnification of the length dimension in the MD direction (transverse direction) with respect to the liner of the core.

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

If the plane compression strength is less than the predetermined compression strength range, it is presumed that the problem I will be caused due to insufficient strength of the sheet 2 as described above. On the other hand, if the plane compressive strength exceeds the predetermined compressive strength range, it is presumed that the ruled line for box making is difficult to be formed, which causes the problem I.
Similarly, if the step repetition rate is less than the above-mentioned predetermined magnification, it is presumed that the problem I will be caused due to insufficient strength of the sheet 2. On the other hand, if the step repetition rate 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.

Like the “predetermined compressive strength range” of the configuration a, the “predetermined compressive strength range” of the configuration b is 50 [kPa] or more and 250 [kPa] or less, and is 80 [kPa] or more. It is preferably 220 [kPa] or less, more preferably 110 [kPa] or more and 190 [kPa] or less.
The “predetermined magnification range” of the 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 preferably 1.45 [times] or more and more preferably 1.55 [times] or less.

It should be noted that the magnification range of the runout ratio 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 run-out rate of any core of the double flute is 1.2 [times] or more and 1.7 [times] or less, and 1.35 [times] or more. It is preferably 0.6 [times] or less, more preferably 1.45 [times] or more and 1.55 [times] or less. The double flute run rate here is the run rate calculated for each stage (the stage corresponding to one and the other flute in the double flute).

<Structure c>
The configuration c has the “configuration in which the angle ratio is within a predetermined ratio range” as described above.
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 measured cardboard material 1.
Hereinafter, the angle ratio will be described with reference to FIG. 2 showing an enlarged main part of the seat 2. Note that FIG. 2 illustrates a state in which the step 10 of the seat 2 is slightly inclined.

The sheet 2 has a structure in which front and back liners 2a and 2b and a core 2c are adhered. The center core 2c constitutes the step 10, and forms a corrugated structure between the liners 2a and 2b.
If the center 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 seat 2, the steps 10 formed by the core 2c may be inclined with respect to the ideal shape. The angle ratio represents the degree of such inclination.

This angle ratio is a ratio calculated based on the angles θ1 and θ2 (intersection angles) at which the center 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 centers of the liners 2a and 2b (that is, the middle 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 in the location where the center core 2c intersects the auxiliary line L.

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 is the angle ratio. This angle ratio is represented by the following equation c.
Angle ratio=|θ1-θ2|/(θ1+θ2)...Equation c
The angle ratio defined in this way is 0 (zero) for the ideal step 10 and has a larger value as the step 10 is biased.

The inventors of the present application have found that the above-mentioned problem III tends to be suppressed when the angle ratio of the sheet 2 is within a predetermined ratio range. Conversely, it has been 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 seat 2 is provided with the configuration c based on the viewpoint III described above.
If the angle ratio exceeds the predetermined ratio range, the heights of the steps 10 in the seat 2 are likely to be uneven, and it is presumed that the problem III is caused.
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>
The configuration d relates to the liner that constitutes the double-sided cardboard of the cardboard material 1, and has the configurations 4 to 7 as described above. It can be said that the liner whose parameters are specified in the configurations 4 to 7 includes the front liner and the back liner and constitutes the seat 2 used for the cardboard material 1.

The “grammage” of the configuration 4 is a parameter indicating the weight [g] per 1 [m ² ] area of the liner.
The “pulp fiber length” of the configuration 5 is the length of the pulp fibers that form the liner. Hereinafter, the pulp fibers forming the liner are referred to as "liner fibers", and the length of the liner fibers is referred to as "liner fiber length".
The "fiber orientation ratio" of Configuration 6 is the ratio of the lateral orientation of the liner fibers to the longitudinal orientation (MD/CD).

The “fiber length ratio” of the configuration 7 is the ratio of the liner fiber length to the pulp fiber length of the core that forms the double-sided cardboard of the cardboard material 1 (liner/core). Hereinafter, the core pulp fiber is referred to as "core fiber", and the length of the core fiber is referred to as "core fiber length".
For configurations 5 and 7, the liner fiber length is an absolute length, while the fiber length ratio is the relative length of the liner fiber length to the core fiber length.

The inventors of the present application have found that the cardboard material 1 having all the configurations 4 to 7 tends to effectively suppress the above-mentioned problem IV. Conversely, it has been found that the cardboard material 1 that does not have any one of the configurations 4 to 7 tends to cause the problem IV.

That is, the cardboard material 1 is provided with the configurations d of configurations 4 to 7 based on the viewpoint IV described above.
--Structure 4--
The smaller the basis weight of the liner for Configuration 4, the lower the strength of the liner tends to be. From this tendency, it is presumed that when the basis weight of the liner is smaller than the predetermined lower limit basis weight, the overall strength of the liner becomes insufficient, which causes the problem IV.

On the other hand, with respect to the liner weight of the configuration 4, not only does the strength of the liner increase as the basis weight increases, but also the thickness of the liner (also referred to as “bulk” or “paper thickness”) tends to increase. From this tendency, it is conjectured that when the basis weight of the liner is larger than the predetermined upper limit basis, the stress due to the folding back of the fold F in the corrugated cardboard material 1 is likely to concentrate on the liner, which causes the problem IV.

Therefore, the “predetermined basis weight range” of the configuration 4 is set to be equal to or higher than the predetermined lower limit basis weight and equal to or lower than the predetermined upper limit basis weight. The predetermined lower limit basis weight is 110 [g/m ² ], preferably 115 [g/m ² ] and more preferably 140 [g/m ² ]. The predetermined upper limit basis weight is 290 [g/m ² ] or less, preferably 240 [g/m ² ] and more preferably 180 [g/m ² ].

--Structure 5--
The shorter the length of the liner fiber for the configuration 5, the lower the degree of entanglement of the liner fibers, and the lower the overall strength of the liner. From this tendency, it is presumed that when the liner fiber length is shorter than the predetermined lower limit fiber length, the liner strength becomes insufficient, which causes the problem IV.

On the other hand, as the length of the liner fiber for the configuration 5 is longer, the overall strength of the liner is improved, but the unevenness of the surface of the liner tends to be larger. From this tendency, when the liner fiber length is larger than the predetermined upper limit fiber length, large irregularities are formed on the surface of the liner, and the specifications and quality required for the cardboard material 1 cannot be satisfied (suitable for the cardboard material 1). There is a risk.
Further, the longer the liner fiber length in the configuration 5, the higher the degree of entanglement of the liner fibers, and the higher the overall strength of the liner. Therefore, the drag force at the fold F and the liner at the fold F are increased. There is also a tendency for the external force required to turn back to increase. From this tendency, it is presumed that when the liner fiber length is larger than the predetermined upper limit fiber length, the stress concentrates on the liner at the fold F and the peripheral portion thereof, which causes the problem IV.

Therefore, the “predetermined fiber length range” of the configuration 5 is set to be not less than the predetermined lower limit fiber length and not more than the predetermined upper limit fiber length. The predetermined lower limit fiber length is 0.55 [mm], preferably 0.70 [mm], and more preferably 0.90 [mm]. The predetermined upper limit fiber length is 1.60 [mm], preferably 1.45 [mm], and more preferably 1.30 [mm].
Even if the overall strength of the liner is secured by the liner fiber length being within the predetermined fiber length range as described above, the smaller the orientation of the liner fiber in the lateral direction, the lower the strength in the lateral direction of the liner. Tend to do. Therefore, the fiber orientation ratio described below specifies a predetermined orientation ratio range.

--Structure 6--
The smaller the fiber orientation ratio for the configuration 6, the stronger the orientation of the liner fibers along the fold F, which tends to cause the problem IV of cracking or avoiding the fold F. From this tendency, it is presumed that when the fiber orientation ratio is smaller than the predetermined lower limit orientation ratio, the problem IV is caused by the orientation of the liner fibers along the fold F.

On the other hand, the larger the fiber orientation ratio for the configuration 6, the stronger the orientation of the liner fibers that intersect the fold F, so that the drag force at the fold F tends to increase, and the liner is folded back at the fold F. There is also a tendency for the external force required to increase. From this tendency, it is presumed that when the fiber orientation ratio is larger than the predetermined upper limit orientation ratio, the stress concentrates on the liner at the fold F and its peripheral portion, which causes the problem IV.

Furthermore, if the fiber orientation ratio is higher than the predetermined upper limit orientation ratio, it tends to cause damage such as tearing or cracking under a tensile load in the longitudinal direction, and the isotropic strength of the basic liner is required. May not be secured (it is not suitable for the cardboard material 1 due to anisotropy of strength).
Therefore, the “predetermined orientation ratio range” of the configuration 6 is set to be equal to or higher than the predetermined lower limit orientation ratio and equal to or lower than the predetermined upper limit orientation ratio. The predetermined lower limit orientation ratio is 1.0, preferably 1.2, and more preferably 1.3. The predetermined upper limit orientation ratio is 2.0, preferably 1.8, and more preferably 1.7 or less.

--Structure 7--
The smaller the fiber length ratio for Configuration 7, the more likely the liner strength will be reduced relative to the core strength. From such a tendency of imbalance in strength, it is presumed that when the fiber length ratio is smaller than a predetermined lower limit ratio, the formability of the fold F is lowered, which may be a cause of causing the problem IV. Guessed.

On the other hand, since the strength of the liner tends to increase relative to the strength of the core as the fiber length ratio for the configuration 7 increases, the drag force against the fold at the fold F tends to increase. The external force required to turn the liner at the eye F also tends to increase. From this tendency, when the fiber orientation ratio is larger than the predetermined upper limit ratio, it is presumed that the problem IV is caused by the stress concentrated on the liner at the fold F and its peripheral portion.

In addition, if the fiber length ratio is larger than the predetermined upper limit ratio, large irregularities are formed on the surface of the liner, and the specifications and quality required for the cardboard material 1 may not be satisfied (not suitable for the cardboard material 1). is there.
Therefore, the “predetermined fiber length ratio range” of the configuration 7 is set to be equal to or higher than the predetermined lower limit ratio and equal to or lower than the predetermined upper limit ratio. The predetermined lower limit ratio is 0.65, preferably 0.80, and more preferably 0.90. The predetermined upper limit ratio is 1.90, preferably 1.60, and more preferably 1.40.

<Structure e>
The configuration e has the “configuration in which the adhesive force is within a predetermined force range” as described above.
The "adhesive force" of the configuration e is a parameter corresponding to the strength of bonding the core 2c of the sheet 2 to the liners 2a and 2b.
The "adhesive strength" here means the adhesive strength between the core 2c and the front liner 2a (glue machine side adhesive strength) and the adhesive strength between the center core 2c and the back liner 2b (single facer side adhesion). (Force) means the average value.

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 has been found that the sheet 2 having an adhesive force outside the range of the configuration e tends to cause the problem V.
That is, the seat 2 is provided with the configuration e based on the viewpoint V described above.
If the adhesive force is below the predetermined force range, it is presumed that the liner 2a, 2b is likely to be peeled off from the core 2c when the cardboard material 1 is manufactured into a box, which causes the 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]
The cardboard material 1 of the present embodiment is provided with at least one of the configurations a to e described above, so that a box in a good state can be manufactured when it is 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 plane compressive strength is within a predetermined compressive strength range, it is possible to secure the box-forming property of the measurement cardboard material 1. It is possible to suppress breakage of a bent portion when assembled in a box.
According to the configuration b, the flat compressive strength of the sheet 2 is within a predetermined compressive strength range and the step-up rate is within a predetermined magnification range, so that the box-making property of the measured cardboard material 1 can be ensured. ..
According to the configuration c, since the angular ratio of the sheet 2 is within the predetermined ratio range, it is possible to ensure the suitability when the measurement cardboard material 1 is printed.
According to the configuration d, since the configurations 4 to 7 are combined, the breakage of the fold F can be suppressed.
According to the configuration e, since the adhesive force of the sheet 2 is within the predetermined force range, it is possible to prevent the liners 2a and 2b of the box assembled from the measurement 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 Examples and Comparative Examples of configurations a to e are described in Item [1], and Examples and Comparative Examples corresponding to 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 Examples and Comparative Examples of configurations a to e, a configuration common to a cardboard material (hereinafter, referred to as “measured cardboard material”) whose parameters are to be measured will be described.
--Measurement target--
The measurement cardboard material is a double-sided cardboard sheet.
This measurement cardboard material has the following sizes.
・Size: Vertical dimension 1300 [mm],
Lateral dimension 1150 [mm],
Height dimension 1800 [mm]

--Preprocessing--
The measurement cardboard material or a part thereof whose parameter is to be measured has been subjected to a pretreatment for 24 hours or more under the temperature and humidity conditions of temperature 23 [°C] and humidity 50 [%] according to JIS Z0203:2000. Then, each parameter was measured.
In addition, the one-tank type starch paste that is commonly used was used as the adhesive for corrugated board that bonds the liner base paper and the core base paper. Further, the measurement cardboard material was manufactured using a corrugator having a stage roll.
--Evaluation--
Each of the example and the comparative example, the details of which will be described later in the next item [2], was evaluated in four grades of “⊚”, “◯”, “Δ”, and “x”.

[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 relating to the configuration a were manufactured by using a corrugator having a corrugating roll having a corrugation number of 34 [peaks/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 height of the stage roll, and the basis weight of the base paper will be described.
In Examples a1 to a6 and Comparative Examples a7 to a9, either one of the single flute and the 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 produced by the stage rolls set to any one stage height among the five stage heights as listed below. The “step height” corresponds to the height of the step in the sheet of the corrugated cardboard material, and is a dimension 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 following common liner base papers were used.
-Liner base paper: 160 [g/m ² ] [MC160: Oji Materia Co., Ltd.]
On the other hand, in Examples a1 to a6 and Comparative Examples a7 to a9, core raw papers having various basis weights prepared according to the manufacturing method disclosed in JP-A-2018-162526 were used. Specifically, for each of Examples a1 to a6 and Comparative Examples a7 to a9, any one of the following five basic weights was adopted. The grammage listed here is the grammage of the base paper that is the material (raw material) of the measured cardboard material.
Basis weight 60 (g/m ² ) (of the core raw paper): Comparative example a8
-Basis weight (of core raw paper) 80 [g/m< ² >]: Example a6
-Basic weight of core paper 170 [g/m< ² >]: Example a5
-Basis weight (of core raw paper) 250 [g/m< ² >]: Examples a1 to a4, Comparative example a9
-Basis weight 320 (g/m ² ) (of the core raw paper): Comparative Example a7

Measurement The basis weight of the base paper (liner base paper, core base paper) forming the material of the cardboard material sheet was measured by the following procedures xa to xd.
-Procedure xa: Pretreatment of the base paper whose basis weight is measured according to JIS Z0203:2000
To do.
-Procedure xb: Cut out the base paper into a size of 250 [mm] x 400 [mm].
-Procedure xc: The weight of the base paper cut out in procedure xb is measured by an electronic balance.
-Procedure xd: The weight measured in the procedure xc is the weight per square meter [g/m ²
]]

The basis weight of the liner (base paper) that forms the sheet of measured cardboard material is measured by the following steps ya to yf.
-Procedure ya: A sheet of measurement cardboard material is immersed in tap water for 15 [minutes].
-Procedure yb: The liner and core of the sheet soaked in step ya are peeled off by hand.
-Procedure yc: The liner peeled off in step yb was dried at 105 [°C] for 20 [min].
dry.
-Procedure yd: The liner dried in procedure yc is 250 [mm] x 400 [mm] in size.
Cut out into.
-Procedure ye: The weight of the liner cut out in the procedure yd is measured by an electronic balance.
-Procedure yf: The weight per unit square meter [g/m ²
]]

Further, the basis weight of the core (base paper) forming the sheet of the measurement cardboard material is measured by the following steps za to zg.
-Procedure za: A sheet of measurement cardboard material is immersed in tap water for 15 [minutes].
-Procedure zb: The liner and core of the sheet soaked in procedure za are peeled off by hand.
-Procedure zc: The liner peeled off in procedure zb is dried at 105[°C] for 20 minutes.
dry.
-Procedure zd: A liner for measuring the basis weight according to JIS Z0203:2000 is pretreated.
Make sense.
-Procedure ze: Cut out the liner into a size of 250 [mm] x 400 [mm]. The wave
If the shape structure remains, cut out into a book size while stretching the wave
You
-Procedure zf: The weight of the liner cut out in procedure ze is measured by an electronic balance.
-Procedure zg: The weight measured in the procedure zf is the weight per square meter [g/m ²
]]

In addition, the basis weight of the liner and core that form the measured cardboard material sheet is the same as the basis weight of the base paper that forms the material of the measured cardboard material even if the same base paper is used as the measurement target. The measured value of can vary by about ±10%.
The thickness dimensions and plane compressive strengths shown in Table 3 below were measured for the above-mentioned measured cardboard materials.

The “thickness dimension” is a parameter corresponding to the thickness of each sheet in the measured cardboard material. This thickness dimension was measured by the following procedures aa to ad.
-Procedure aa: If the total number M of corrugated cardboard materials is an odd number, round half the number M/2.
Sampling the upper and lower five steps based on the entered step (that is, the middle step)
R. When collecting the test piece, care was taken not to collapse the step. all
If the number of stages M is an even number, 5 stages are used up and down based on half the number of stages ((M/2)+1)
Take a sheet of minutes.
-Procedure ab: 5 [cm] x 5 [cm] size from the ten sheets collected in procedure aa
Cut a test piece into a square.
-Procedure ac: Measure the thickness of the test piece cut out in procedure ab with the following compliant standards, measuring equipment, and
Measure under constant conditions.
＞Compliance standard: Corrugated board industry standard T0004:2000
＞Measuring equipment: Thickness gauge (Mitutoyo Ratchet, model number K470101K)
> Measurement conditions: Plunger diameter 16 [mm], load 3923 [mN]
-Procedure ad: From the thickness measured in procedure ac, a disturbance that reduces the accuracy of the measurement result (requires
Factor) that can be a factor)
What was taken was the thickness dimension.
In the procedure "exclusion of numerical values that may cause disturbance" in the procedure ad, when each numerical value measured in the procedure ac is used as a population, a numerical value whose standard deviation deviates from ±3σ is excluded.

“Plane compression strength” is a parameter corresponding to the crush resistance of a sheet of measured cardboard material. This plane compressive strength was measured by the following procedures aA to aD.
-Procedure aA: Similar to procedure aa, if the total number M of corrugated cardboard materials is an odd number,
Five upper and lower tiers based on the rounded tier (that is, the middle tier) of the number of tiers M/2
Take a sheet of minutes. The steps do not collapse when collecting the test pieces.
I was careful. When the total number of stages M is an even number, half the number of stages ((M/2)+1
), collect the upper and lower five steps of sheets.
-Procedure aB: A circular sample with a diameter of 6.4 cm from the ten sheets collected in procedure aA.
Cut out the test piece.
-Procedure aC: Plane compressive strength of the test piece cut out in procedure aB is measured according to the following standard.
Measure under the conditions of equipment, test speed and parallelism. Note that parallelism means flatness.
It represents the degree of parallelism of the jig for surface compression.
> Standards: JIS Z 0403-1:1999
＞Measuring equipment: compression with a jig for plane compression (made by Tester Sangyo Co., Ltd.)
Testing machine (manufactured by A&D Co., Ltd., RTF1350)
>Test speed (measurement condition): 12.5±2.5 [m/min]
>Parallelism (measurement condition): 1/1000 or less of compression dimension-Procedure aD: Measured from the plane compressive strength measured in procedure aC, as in procedure ad above.
Exclude numerical values that may cause disturbances (factors) that reduce the accuracy of the fixed results, and
The average value was taken as the plane compressive strength.

--Evaluation--
With respect to Examples a1 to a6 and Comparative Examples a7 to a9 in which the thickness dimension and the plane compression strength were respectively measured as described above, the box-forming property and ruled cracks described below were evaluated.
The "box-making property" refers to the accuracy of a box in which a cardboard piece (hereinafter referred to as "evaluation cardboard piece") cut out by a cut line that crosses the folds of the measurement cardboard material is assembled by hand (handmade). It is a corresponding evaluation standard. As a method of hand-assembling, the cut pieces of corrugated cardboard were folded at predetermined ruled lines, adhered with a hot melt adhesive, and made into boxes.
The method of assembling the evaluation cardboard pieces by the box making system is the same whether it is manually assembled or by the box making system. Therefore, it can be said that the box-making property of the evaluation cardboard piece assembled by hand is correlated 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 measured cardboard material was punched out in the following shapes and sizes with a sample cutter (CF2-1218 manufactured by Mimaki Engineering Co., Ltd.) as shown below.
-Shape: Pattern in which the A-type cardboard box is developed-Size: Width of the side plate of the A-type cardboard box 356 [mm],
The width of the end plate of the A-type cardboard box is 159 [mm],
Height 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]) evaluated cardboard pieces have good box-making properties.
◯: Out of 100 corrugated cardboard pieces, 1 to 2 corrugated pieces have poor box-making properties.
-[Delta]: 3 [sheets] out of 100 [sheets] of corrugated cardboard pieces have poor box-making properties.
*: Out of the evaluation cardboard pieces of 100 [sheets], 4 [sheets] or more have a poor box-making property.
In addition, in Example a4 in which the box-making property was evaluated as “◯”, the box-making property of 2 [sheets] was poor.

Here, "good box-making property" means that the distance dimension between the following folded portions A and B in the evaluation cardboard piece is less than the predetermined distance dimension.
-Folded part A: a part where ruled lines (elements different from folds) for box making are provided-Folded part B: part actually folded when assembled into a box (during box making) "Predetermined distance "Dimension" is 2.0 [mm] for the dimension in the direction perpendicular to the folds of the evaluation cardboard piece (MD direction) and 5 [mm] for the dimension in the direction parallel to the folds (CD direction). ].
On the other hand, "poor box formability" means that the distance dimension between the folded portions A and B in the evaluation cardboard piece is equal to or greater than the predetermined distance dimension.

In addition, "ruled crack" means that the bent portion of the evaluation cardboard piece is broken when it is assembled into a box. This crease crack is observed by visually observing a box whose box-forming property is evaluated (that is, a box in which evaluation cardboard pieces are assembled, hereinafter referred to as "evaluation box").
This ruled crack was evaluated according to the following criteria.
⊚: No creases were found in all (100 [boxes]) evaluation boxes.
-○: A crack occurred in 1 to 2 [boxes] of 100 [boxes] evaluation boxes.
-△: A crack was found in 3 [boxes] of 100 [boxes] evaluation boxes.
*: Ruled cracks were found in 4 or more boxes out of 100 [boxes] evaluation boxes.
Regarding Examples a3, a5, a6 and Comparative Example a8, which were evaluated as “◯” for the ruled cracks, 1 [box] was found to have the ruled cracks in Examples a3, a5, a6, and Comparative Example a8. There was a crack on 2 [box].

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

According to Comparative Example a7, when the thickness dimension is larger than 9.6 [mm], the liner base paper is not fully extended and is broken when folded by the crease line for box making, and the evaluation of crease crack becomes poor. Inferred.
From this comparative example a7, when the plane compressive strength is larger than 250 [kPa], it becomes difficult to insert a ruled line for box making (because the formability of the ruled line is deteriorated), and at a place other than the ruled line for box making. It is also presumed that the product is bent and the box-making property is evaluated poorly.

From Comparative Example a8, when the plane compressive strength is less than 50 [kPa], the bending strength of the evaluation cardboard piece is insufficient, and the corrugated board is likely to be bent at a place other than the ruled line for box making, and thus 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 evaluation cardboard piece has insufficient bending strength and is easily bent at a place other than the ruled line for box making. It is presumed that the evaluation of box properties will be poor.

In view of the above Comparative Examples a7 to a9, it is inferred from Examples a1 to a6 that the smaller the thickness dimension in the range of 9.6 [mm] or less, the more the occurrence of ruled cracks is suppressed. On the other hand, it is presumed that the larger the thickness in the range of 2.0 [mm] or more, the more the bending at a place other than the ruled line for box making is suppressed.
From Examples a1 to a6, it can be inferred that if the plane compressive strength is 250 [kPa] or less, the defects of the ruled lines formed for box making can be suppressed. On the other hand, if the plane compressive strength is 50 [kPa] or more, it is presumed that the bending strength of the evaluation cardboard piece is ensured 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 plane compressive strength is 50 [kPa] or more and 250 [kPa] or less, box-making property It can be said that it is possible to achieve both the securing of the gap and the suppression of the ruled crack.

<Structure b>
--Measurement target--
The same liner base paper as in Examples a1 to a6 and Comparative examples a7 to a9 was used as the measurement cardboard material used in Examples b1 to b3 and Comparative Examples b4 and b5 relating to the configuration b, and the following center core base paper was used.
・Core raw paper: 170 [g/m ² ] [LB170: Oji Materia Co., Ltd.]
In addition, the measurement cardboard materials used in Examples b1 to b3 and Comparative Examples b4 and b5 were manufactured by using a corrugator having roll rolls having various roll ratios shown in Table 4 below. Further, for each of Examples b1 to b3 and Comparative Examples b4 and b5, the plane compressive strength was measured by the same procedure as the above-described procedures aA to aD, and the plane compressive strength shown in Table 4 below was measured. ..

The “step take-up rate” is a parameter corresponding to the magnification of the length dimension in the MD direction with respect to the core liner. This step repeat rate was measured by the following procedures ba to bg.
-Procedure ba: Similar to the procedures aa and aA, when the total number M of corrugated cardboard materials is an odd number,
Up to half the number of rounded M/2 rounded columns (that is, the middle column)
Collect the lower 5 sheets. When collecting the test piece, the step
I was careful not to let it go. When the total number of stages M is an even number, half the number of stages ((M/2
) +1) is used as the standard for collecting the upper and lower five sheets.
-Procedure bb: The direction in which the core ridges are continuous from the ten sheets collected in procedure ba (transverse direction)
Direction, MD direction) is 20 [cm] and is orthogonal to the center core mountain (vertical direction).
Direction, CD direction) to a size of 10 [cm].
-Procedure bc: The test piece cut out in procedure bb is immersed in tap water for 24 hours.
-Procedure bd: After the immersion of procedure bc, the front and back liners are peeled off and the core is taken out.
-Procedure be: The length of the core that has been taken out in Procedure bd and stretched by hand
Is measured with a ruler.
-Procedure bf: "Full length of core" measured in procedure be and cut out in procedure bb
The length in the direction in which the core piles of the
The length of the step is 20 [cm] here, and
To calculate.
Corrugation rate = length of fully extended core/length of original cardboard sheet ... formula b
-Procedure bg: Similar to the above-mentioned steps ad and aD, it is measured from the stage repetition rate calculated in step bf.
Exclude numerical values that may cause disturbances (factors) that reduce the accuracy of the fixed results, and
The average value was taken as the step repetition rate.

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

In Examples b1 to b3, the step repetition rate is 1.2 [times] or more and 1.7 [times] or less, and the plane compressive strength is 50 [kPa] or more and 250 [kPa] or less. Therefore, a good evaluation of at least “Δ” was obtained for the box-making property.
On the other hand, Comparative Example b4 in which the step yield rate is less than 1.2 [times] and the plane compression strength is less than 50 [kPa], and the plane compression rate is greater than 1.7 [times] and the plane compression strength is higher. In Comparative Example b5 having a value of more than 250 [kPa], the box-making property was evaluated as "x", which was a poor evaluation.

From Comparative Example b4, since the plate rolling rate is less than 1.2 [times] and the plane compressive strength is less than 50 [kPa], the bending strength of the evaluation corrugated cardboard piece is insufficient, so that the box is manufactured. It is presumed that it is easy to bend at a place other than the ruled line for the box, and the evaluation of the box-making property becomes poor.
From Comparative Example b5, it was difficult to insert the ruled lines for box making because the run-out rate was greater than 1.7 [times] and the plane compression strength was greater than 250 [kPa] (ruled line formability). It is presumed that the evaluation of the box-making property becomes poor because the sheet is bent at a place other than the ruled line for box-making, and the box-making property becomes poor.

In view of Comparative Examples b4 and b5 described above, from Examples b1 to a3, since the step repetition rate is 1.2 [times] or more and the plane compression strength is 50 [kPa] or more, It is presumed that bending at locations other than the ruled lines for the box can be suppressed. Further, it is presumed that the line-forming rate of 1.7 [times] or less and the plane compressive strength of 250 [kPa] or less can suppress defects in the ruled lines formed for box making.
Therefore, if the stage repeat rate is 1.2 [times] or more and 1.7 [times] or less, and the plane compressive strength is 50 [kPa] or more and 250 [kPa] or less, box making It can be said that the sex can be secured.

<Structure c>
--Measurement target--
In Examples c1 to c3 and Comparative Example c4 relating to the configuration c, the same base paper as in Examples b1 to b3 and Comparative Example b4 was used, and A was produced using a corrugator having a stage roll having the specifications shown below. Flute measurement Cardboard material was used.
・Step height: 4.5 [mm]
・Number of steps: 34 [mountain/30 cm]
Then, the measured cardboard materials manufactured so as to have the angle ratios shown in Table 5 below were used for 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 measured cardboard material. This angle ratio was measured by the following procedures ca to cf.
・Procedure ca: In the sheet of measurement corrugated cardboard, one crest of the core is set in the longitudinal direction (CD direction).
Take a photo from.
・Procedure cb: The height of one mountain in the photo taken in procedure ca is 10 cm or more.
And print it on the 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 and back liners (center in the TD direction).
-Procedure cd: Among the intersections of the auxiliary line drawn in procedure cc and the core, two adjacent arbitrary points
select.
-Procedure ce: At each of the two points selected in procedure cd, an auxiliary line and a core are formed.
Of the angles, the acute angle 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.

--Evaluation--
The printability was evaluated for Examples c1 to c3 and Comparative Example c4 in which the angle ratio was obtained as described above.
The "printability" is the suitability when printing is performed on the measurement cardboard material, and is an evaluation criterion corresponding to the quality of the printing performed on the measurement cardboard material.
This printability was evaluated by the following procedures cA to cC.
-Procedure cA: 500 [mm] x 1 with the long side in the MD direction of the sheet of measurement cardboard material
Cut to a size of 350 [mm].
-Procedure cB: Direct flexographic printing machine D for the test piece cut in procedure cA
550 [line/in by YNA FLEX160 (manufactured by Bobst)
Water-based flexo ink (part number: Su
per-EX FK-99, manufactured by Sakata Ink Co., Ltd.) in the following order:
Printed.
> Order of coating: Red, ink, indigo, yellow, varnish. Step cC: The finish printed in step cB was visually observed.

The above printability was evaluated according to the following criteria.
⊚: There is no unevenness of ink inking and the printing finish is good.
-○: Almost no unevenness of ink inking and no practical problems.
・△: Ink unevenness is slightly large, but there is no problem in practical use.
X: Ink unevenness is very large, there are practical problems, and the quality is significantly poor.

In Examples c1 to c3, the angle ratio was 0.30 or less, the printability was 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, a rating of “◯” or higher was obtained, and in Example c1 having an angle ratio of 0.05 or less, a rating of “⊚” was obtained.
On the other hand, in Comparative Example c4 in which the angle ratio is larger than 0.30, the printability was evaluated as “x”, which is a practical problem.

From Comparative Example c4, it is estimated that the angle ratio is larger than 0.30, and the heights of the steps become uneven, so that the evaluation of the printability becomes poor. Alternatively, the fact that the test piece is likely to be deformed in the direction according to the inclination of the step when the ink is inked is also one of the reasons why the evaluation of printability is inferior.
On the other hand, it is presumed from Examples c1 to c3 that the angular ratio of 0.30 or less suppresses the variation in the height of the step and obtains printability without any practical problems. From the examples c1 and c2, the variation in the height of the step is surely suppressed by the angle ratio being 0.15 or less, and from the example c1 by the angle ratio being 0.05 or less, It is estimated that it will be further suppressed.
Therefore, it can be said that printability can be ensured if the angle ratio is 0.30 or less.
<Structure d>
--Measurement target--
First, the configurations of the measurement cardboard materials of Examples d1 to d11, d21 to d32 and Comparative Examples d12 to d20, d33 to d36 relating to the configuration d shown in Tables 6 to 9 below will be described.

For the liner base papers of Examples d1 to d11, d21 to d32 and Comparative Examples d12 to d20, d33 to d36 related to the configuration d, as shown in Table 6 to Table 9 above, any one of the following basis weights was used. One grammage was adopted. These liner base papers were produced according to the method for producing a liner for cardboard disclosed in Japanese Patent No. 6213364.
-Basis weight (of liner base paper) 120 [g/m ² ]
・Basic weight (of liner base paper) 160 [g/m ² ]
・Basis weight 280 [g/m ² ] (of liner base paper)
・Basis weight (of liner base paper) 100 [g/m ² ]
・Basis weight (of liner base paper) 320 [g/m ² ]
· 110 [g/m ² ] basis weight (of liner base paper)
・Basis weight 105 [g/m ² ] (of liner base paper)

Further, in Examples d1 to d11, d21 to d32 and Comparative Examples d12 to d20 and d33 to d36, as shown in Tables 6 to 9 above, one of the two types of basis weights shown below is used. Adopted quantity. These core raw papers were manufactured according to the manufacturing method of JP-A-2017-218721.
・Basis weight (of core paper) 120 [g/m ² ]
・Basis weight (of core paper) 160 [g/m ² ]
The grammage of each of the liner raw paper and the core raw paper described above is the grammage of the raw paper forming the material (raw material) of the corrugated cardboard material, and the temperature is 23[° C.] and the humidity is 50[%] in accordance with JIS Z0203:2000. It was measured in the normal state where the pretreatment was performed for 24 hours or more under the temperature and humidity conditions.

The measurement cardboard materials of Examples d1 to d11, d21 to d32 and Comparative Examples d12 to d20, d33 to d36 were double-faced cardboards, and any one of the following five types of flutes was adopted.
・A Flute ・B Flute ・C Flute ・AB Flute ・AC Flute

The measurement cardboard materials of Examples d21 to d27, d32 and Comparative Examples d35, d36 are formed by laminating five base papers having the following basis weights in the order from one side in the height direction to the other side.
-Liner base paper: basis weight 160 [g/m ² ]
・Core raw paper: basis weight 160 [g/m ² ]
・ Medium liner base paper: basis weight 160 [g/m ² ]
・Core raw paper: basis weight 160 [g/m ² ]
-Liner base paper: basis weight 160 [g/m ² ]

Further, the measurement cardboard material of Example d28 is configured by stacking five base papers having the following basis weights in order from one side in the height direction to the other side.
・Liner base paper: basis weight 280 [g/m ² ]
・Core raw paper: basis weight 160 [g/m ² ]
・ Medium liner base paper: basis weight 160 [g/m ² ]
・Core raw paper: basis weight 160 [g/m ² ]
・Liner base paper: basis weight 280 [g/m ² ]

Further, the measurement cardboard material of Example d29 is configured by stacking five base papers having the following basis weights in order from one side to the other side in the height direction.
-Liner base paper: basis weight 160 [g/m ² ]
・Core raw paper: basis weight 120 [g/m ² ]
・ Medium liner base paper: basis weight 120 [g/m ² ]
・Core raw paper: basis weight 120 [g/m ² ]
-Liner base paper: basis weight 160 [g/m ² ]

In the production of the liner base paper (for the front liner and the back liner) constituting the measurement cardboard material, the raw pulp pulp fiber classifier (MAX-F700, manufactured by Aikawa Iron Works Co., Ltd.) was used, and the above Tables 6 to 9 were used. The pulp fiber length is adjusted as described in 1.
Further, in the production of the liner base paper (for the front liner and the back liner) that constitutes the measurement cardboard material, the jet wire ratio is adjusted when the liner base paper is made, and the jet wire ratio is set forth in Tables 6 to 9 above. Thus, the fiber orientation ratio was adjusted. The jet wire ratio is the ratio (J/W) of the flow velocity (J) of the pulp dispersion liquid to the traveling speed (W) of the wire in the paper machine. By adjusting the jet wire ratio, the flow of the dispersion liquid near the wire can be controlled in the laminar flow region.

The "fiber length" is measured by the following procedures da to de.
Step da: The second step from the top of the cardboard material is cut into a 40 [cm] square and 40
A [cm] square cardboard sheet was used for measurement. Cardboard cutout position
It was in the middle of the seat width. Soak the cardboard sheet in deionized water for 15 minutes
Pickle and remove from deionized water.
Step db: The liner base paper (front liner and
By peeling each of the back liners by hand so that the liner base paper does not break
Separate from the core raw paper.
Step dc: Each of the liner base paper and the core base paper separated in Step db is deionized water.
It was soaked in water, adjusted to a concentration of 2%, and then soaked for 24 hours.
Step dd: 24 each of the liner base paper and the core base paper whose densities were adjusted by the step dc
After soaking for 20 minutes, use a standard disintegrator (made by Kumagai Riki Kogyo Co., Ltd.) for 20 minutes
Then, the pulp is decomposed into fibers.
Step de: Fractionation of the slurry (pulp fiber) after disaggregation in step dd and measurement of the following fiber length
The fiber length according to JIS P 8226-2:2011 using a machine
did.
-Fiber length measuring machine: Product number FS-5 UHD base unit, manufactured by Valmet Co., Ltd. Further, the "fiber length ratio" is based on the fiber length of the liner base paper and the fiber length of the core base paper measured in the above steps da to de. It was calculated by the following formula d.
Fiber length ratio=fiber length of liner base paper/fiber length of core base paper... Formula d

"Fiber orientation ratio" is measured by the following procedures dA to dD.
Step dA: Same as step da above Step dB: Same as step db above Step dC: Each of the liner base paper and the core base paper separated in step dB are cylinder-shaped.
Moisture disappears with a layer (product number: MR3D, manufactured by Japo Co., Ltd.)
To dry.
Step dD: The fiber orientation ratio between the liner base paper and the core base paper dried in Step dC is calculated as follows.
Measurement is performed using the characteristic evaluation device characteristics.
-Fiber length measuring machine: Part number FS-5 UHD base unit, manufactured by Valmet Co., Ltd. The value of the fiber orientation ratio has a minimum value of 1.0 due to the setting specifications of the fiber length measuring machine.
--Evaluation--

In Examples d1 to d11, d21 to d32 and Comparative Examples d12 to d20 and d33 to d36, the breakability was evaluated for all the folds (ends) of the measured cardboard material. "Break cracking property" is an evaluation standard corresponding to the difficulty of breakage when a cardboard material is bent. "Damage" includes cracks, tears, and tears in the liner base paper at the folds.

In the evaluation of breakability, it was confirmed whether or not a liner base paper of at least one of the front liner and the back liner was cracked at the fold, and the confirmation result was evaluated according to the following criteria. The “fold point” is an area including the periphery of the fold.
⊚: No cracks were observed in the folds ○: 1 to 2 cracks were observed in the folds Δ: 3 to 4 cracks were observed in the folds ×: 5 or more cracks were observed in the folds In Examples d1 to d11, d21 to d32 and Comparative Examples d12 to d20 and d33 to d36, “⊚” with the highest evaluation and “∘” with the next highest evaluation are good evaluations, and the lowest evaluation. “×” and “Δ” with the next lowest evaluation were evaluated as poor evaluations.

In Examples d1 to d11 and d21 to d32, the basis weight of the liner base paper is 110 [g/m ² ] or more and 290 [g/m ² ] or less, and the liner base paper has a pulp fiber length of 0.55 [. mm] or more and 1.60 [mm] or less, the fiber orientation ratio is 1.0 or more and 2.0 or less, and the fiber length ratio is 0.65 or more and 1.90 or less. There was a score of “◯” or higher for breakability.
In particular, the basis weight of the liner base paper is 140 [g/m ² ] or more and 180 [g/m ² ] or less, and the pulp fiber length of the liner base paper is 0.90 [mm] or more and 1.30. [Mm] or less, fiber orientation ratio of 1.3 or more and 1.7 or less, and fiber length ratio of 0.90 or more and 1.40 or less Examples d3, d11, d23, For d30 to d32, the best evaluation of "⊚" was obtained for the breaking property.

On the other hand, in Comparative Examples d12, d13, d15, and d33 to d36, the pulp fiber length of the liner base paper is out of the range of 0.55 [mm] to 1.60 [mm], and the breaking property is “Δ”. The following poor evaluations were obtained.
Further, in Comparative Example d14, the fiber orientation ratio was larger than 2.0, and the evaluation of “x” was obtained for the breakability. Further, in Comparative Examples d16 and d17, the fiber length ratio was out of the range of 0.65 to 1.90, and a score of “Δ” was obtained for the breaking cracking property. Further, in Comparative Examples d18 to d20, the basis weight of the liner base paper was out of the range of 110 [g/m ² ] to 290 [g/m ² ] and the breakability was rated as “Δ” or less. ..

From Comparative Examples d12, d13, and d33 to d36, since the pulp fiber length is less than 0.55 [mm], the pulp fiber length is too short so that the pulp fibers are not entangled with each other and the overall strength of the liner base paper is low. Since it becomes weaker, it is presumed that the breakability becomes poor. From Comparative Example d15, the pulp fiber length is larger than 1.60 [mm], and from Comparative Example d14, the fiber orientation ratio is larger than 2.0. Are concentrated, it is presumed that the breakability becomes poor.

From Comparative Example d16, since the fiber length ratio is smaller than 0.65, the overall strength of the liner base paper is relatively reduced with respect to the core base paper, so that the formability of the folds is reduced and it is defective. It is presumed that a good breakability was obtained. From Comparative Example d17, it is estimated that when the fiber length ratio is larger than 1.90, stress concentrates on the liner base paper at the folds and the peripheral portions thereof, resulting in poor crease breakability.
From Comparative Examples d18 and d19, it is speculated that when the basis weight is smaller than 110 [g/m ² ], the overall strength of the liner base paper is reduced, and thus the breakability is poor. From Comparative Example d20, it is estimated that when the basis weight is larger than 290 [g/m ² ], stress concentrates on the liner base paper at the folds and the peripheral portions thereof, resulting in poor crease cracking properties.

In view of the comparative examples d12 to d20 and d33 to d36, from the examples d1 to d11 and d21 to d32, the basis weight of the liner raw paper is 110 [g/m ² ] or more and 290 [g/m ^{2 ].} ], the liner base paper has a pulp fiber length of 0.55 [mm] or more and 1.60 [mm] or less, and a fiber length ratio of 0.65 or more and 1. When it is 90 or less, the overall strength of the liner base paper is secured, and when the fiber orientation ratio is 1.0 or more and 2.0 or less, the strength in the lateral direction of the liner base paper is secured. Therefore, it is presumed that the breakability is improved.
From Examples d3, d11, d23 and d30 to d32, the pulp fiber length is 0.9 [mm] or more and 1.30 [mm] or less, and the fiber orientation ratio is 1.3 or more and 1 When it is less than 0.7, the overall strength of the liner base paper and the strength in the lateral direction of the liner base paper are raised, and it is presumed that the breakability becomes better.

Therefore, the basis weight of the liner base paper is 110 [g/m ² ] or more and 290 [g/m ² ] or less, and the pulp fiber length of the liner base paper is 0.55 [mm] or more and 1.60. If it is [mm] or less, the fiber orientation ratio is 1.0 or more and 2.0 or less, and the fiber length ratio is 0.65 or more and 1.90 or less, crease breakage is suppressed. I see that I can do it. Further, it can be said that the appearance of the cardboard box using the measured cardboard material can be prevented from being deteriorated and the quality of the cardboard box can be secured.

<Structure e>
--Measurement target--
In Examples e1 to e3 and Comparative Example e4 relating to the configuration e, the same base papers as in Examples b1 to b3, c1 to c3, d1 to d3 and Comparative Examples b4, c4 and d4 were used, and Examples c1 to c3 and d1 were used. .About.d3 and the measurement corrugated cardboard material of A flute manufactured by using the corrugator having the roll rolls similar to those of Comparative Examples c4 and d4.
The adhesive force was measured for each of Examples e1 to e3 and Comparative Example e4 using the measurement corrugated cardboard material manufactured as described above, and the adhesive force 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).

"Adhesive force" is a parameter corresponding to the peeling resistance value of the adhesive portion between the liner and the top of the core (the portion corresponding to the maximum value) in the sheet of measured cardboard material. To put it plainly, it is a parameter that corresponds to the difficulty of peeling of the liner forming the sheet of corrugated cardboard material.
This adhesive force was measured by the following procedures ea to ee.
-Procedure ea: If the total number M of corrugated cardboard materials is an odd number, round half the number M/2.
Sampling the top and bottom 10 sheets based on the inserted row (that is, the middle row)
, Cut out 20 sheets without deformation (for example, dents). The total number M is
In case of an even number, the half-stage number ((M/2)+1) is used as the standard
Tissue is collected and 20 sheets without deformation (for example, dents) are cut out.
-Procedure eb: From the sheet cut out in procedure ea, the size of the test sun is changed to the size shown below.
Pull the sample cutter (Mimaki Engineering Co., Ltd., CF
2-1218) and cut out.
Direction parallel to the corrugated structure of the core (vertical direction <CD direction>): 50 [mm]
Direction orthogonal to the corrugated structure of the core (lateral direction <MD direction>): 85 [mm]
-Procedure ec: Prepare 10 sheets of each of the front and back samples cut out in the procedure eb. Ingredient
Physically, 10 sheets for measuring the adhesive force on the single facer side, and
-Prepare ten sheets for measuring the adhesive force on the machine side.
-Procedure ed: The sample prepared in procedure ec is attached to the following measuring device and conforms to the following.
The adhesive strength was measured under the standard and measurement conditions.
> Standards: JIS Z0402: 1995
> Measuring device: compression tester (RTF1350 manufactured by A&D Co., Ltd.)
＞Measurement condition: Pin attachment (Japan TMC Co., Ltd.) is attached to the sample
Then, place it on the measuring device and set the peeling surface to the upper side at 13 [mm/min.
] When the load is applied at the speed of
Measure the weight.
・Procedure ed: Similar to procedures ad, aD, and aC, is the adhesive force measured in procedure ed?
Exclude values that may 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 the examples e1 to e3 and the comparative example e4 in which the adhesive force was obtained as described above.
The "liner peeling" is an evaluation standard that corresponds 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: Crossing over the folds of the measured corrugated cardboard material as in the case of the evaluation of the box-forming property according to the configurations a and b.
Evaluating with a cutting line Sample cardboard piece of sample (Mimakie Co., Ltd.
It is cut out using CF2-1218 manufactured by Engineering Co., Ltd.). In addition, one
When cutting out the first evaluation cardboard piece, replace it with a new cutter blade.
, This cutter blade was used without replacement until the 100th (last) piece.
-Procedure eB: Assemble the evaluation cardboard pieces cut out in procedure eA by hand. "Credit
Valuable corrugated cardboard is a sample of corrugated cardboard material with the following shapes and sizes.
Lucutter (CF2-1218 manufactured by Mimaki Engineering Co., Ltd.)
The test pieces were punched out in the following numbers.
Shape: A type cardboard box unfolded pattern
Size: Width width 356 [mm] of the side plate of A-type cardboard box,
The width of the end plate of the A-type cardboard box is 159 [mm],
Height of A type cardboard box 256 [mm]
Number of sheets: 100 [sheets]
-Procedure eC: peeling of the liner (sheet) in the evaluation box assembled in procedure 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 [boxes]) evaluation boxes.
◯: Peeling of the liner was observed in 1 to 2 [boxes] of 100 [boxes] evaluation boxes.
-: Peeling of the liner was observed in 3 to 4 [boxes] of the 100 [boxes] evaluation boxes.
*: The peeling of the liner was observed in 5 [boxes] of 100 [boxes] evaluation boxes.
For Examples e2 and e3 in which the liner peeling was evaluated as “◯”, the liner peeled in 1 [box] in Example e2 and the liner peeled in 2 [box] in Comparative Example e3. It was observed. In addition, there was no example or comparative example in which the evaluation of “Δ” was obtained for the liner peeling.

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

When the average adhesive force is 140 [N] or more, the liner becomes difficult to peel off when the evaluation cardboard piece is cut out from the measurement cardboard material, and the liner does not easily separate even when the evaluation box is assembled from the evaluation cardboard piece. Inferred. Furthermore, if the average adhesive force is 220 [N] or more, it is presumed that the peeling of the liner can be prevented both when the evaluation cardboard piece is cut out and when it is assembled. Therefore, the average adhesive force is 140 [N]. If it is above, it can be said that the liner of the evaluation box is hard to peel off. Furthermore, 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 secured.

[3. Example combining three configurations]
Finally, an example abc combining the configurations a, b and c will be described.
In addition, the details of the measurement target and the evaluation of the example abc are the same as those described above, unless otherwise specified.
--Measurement target--
Example abc was evaluated on a measured cardboard material that also had the parameters listed below.
・Thickness: 5.1 [mm]
・Plane compression strength: 170 [kpa]
・ Angle ratio: 0.00
-Average adhesive force: 237.5 [N]
> Single facer side: 230 [N]
> Glue machine side: 245 [N]

--Evaluation--
With respect to the measurement corrugated cardboard material of Example abc, box-making property, ruled crack, printability, and liner peeling were evaluated. As a result, excellent evaluations (“A” above) were obtained in all of the box-making property, line cracking, printability, and liner peeling.
From the evaluation results of the example abc, it can be seen that when the configurations a, b, and c are combined, the evaluations corresponding to the configurations a, b, and c are excellent and are excellent.

Further, when the measured cardboard material having the above parameters is used in the box making system, it is presumed that the box assembling speed (packing speed) can be increased. The reasons are as follows.
・Reason α: Liner peeling is suppressed because a good evaluation of liner peeling is obtained.
The process of cutting out the measured cardboard material into evaluation cardboard pieces (that is,
It is speculated that the speed of liter processing can be increased. In other words,
High-speed slitter for corrugated cardboard material in slitting
Even if it is cut out with, it is inferred that the liner will not easily peel off due to the impact.
When.
・Reason β: Since a good evaluation of box making can be obtained, the box making must be ensured before making the box making.
It is assumed that the packaging speed of the system can be increased. In other words, the rating
A device unit for assembling cardboard pieces (for example, a robot arm for packaging)
) Folds the cardboard material to be assembled at high speed,
It is inferred that it bends (it can suppress bending at points other than ruled lines)
Be done.

[III. Modification]
The above embodiment is merely an example, and is not intended to exclude various modifications and application of techniques that are not explicitly shown in this embodiment. Each configuration of the present embodiment can be variously modified and implemented without departing from the spirit thereof. In addition, they can be selected as needed and can be appropriately combined.
For example, if the 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 made on the folds, and the surface of the liner in the cardboard material is It is preferable that the portion that is folded back 180[°] from the provided ruled line as a starting point (for example, the ruled line inside) is a fold. On the other hand, when the cardboard material is a material other than that for the box making system, processing such as cuts and perforations may be performed at the folds.

The liner base paper and the core base paper used for the above-described cardboard material and measurement cardboard material are not limited to the products of the product numbers given in the examples, and the liner base paper produced by the method for producing a cardboard liner disclosed in Japanese Patent No. 6213364 and JP-A-2017 A core raw paper produced by the method for producing a corrugated paper base paper of Japanese Patent No. 218721 may be used.

1 Cardboard material 10th stage (wavy)
2 sheet 20 sheet pair 21 first sheet 22 second sheet 23 third sheet F fold L auxiliary line L1 vertical dimension (first dimension)
L2 horizontal dimension (second dimension)
L3 height dimension (third dimension)

Claims (12)

In the continuous 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 linearly extending along the first direction, A corrugated cardboard material in which the sheets are stacked along a third direction orthogonal to both one direction and the second direction,
The pulp fiber length of the liner is 0.55 [mm] or more and 1.60 [mm] or less,
The fiber orientation ratio, which is the ratio of the orientation in the second direction to the orientation in the first direction of pulp fibers in the liner, is 1.0 or more and 2.0 or less,
A cardboard material, wherein a fiber length ratio, which is a ratio of the pulp fiber length of the liner to a pulp fiber length of a core forming the double-sided cardboard, is 0.65 or more and 1.90 or less. The pulp fiber length of the liner is 0.90 [mm] or more and 1.30 [mm] or less,
The fiber orientation ratio is 1.3 or more and 1.7 or less,
The cardboard material according to claim 1, wherein the fiber length ratio is 0.90 or more and 1.40 or less. The sheet is
The thickness dimension measured according to the corrugated board industry standard T0004:2000 is 2.0 [mm] or more and 9.6 [mm] or less,
The plane compressive strength measured in accordance with JIS Z 0403-1:1999 is 50 [kPa] or more and 250 [kPa] or less.
The cardboard material according to claim 1 or 2, characterized in that. The thickness dimension is 5.1 [mm] or more,
The plane compressive strength is 170 [kPa] or more.
The cardboard material according to claim 3, wherein: The sheet has an average adhesive force of 140 [N] or more measured on the single facer side and the glue machine side according to JIS Z0402:1995.
The cardboard material according to claim 1 or 2, characterized in that. The average value of the adhesive force is 190 [N] or more.
The cardboard material according to claim 5, wherein: The sheet, at the two locations where the core intersects with a virtual auxiliary line extending in the second direction in the center of the front liner and the back liner when viewed from the first direction, and at the two adjacent positions, the core and The ratio obtained by dividing the difference between two acute angles formed by the auxiliary line by the sum of the two acute angles is 0.30 or less.
The cardboard material according to claim 1 or 2, characterized in that. The ratio divided by the sum of the two acute angles is 0.15 or less
The cardboard material according to claim 7, wherein: The stage repeat rate is 1.2 [times] or more and 1.7 [times] or less,
The sheet has a plane compression strength of 50 [kPa] or more and 250 [kPa] or less measured according to JIS Z 0403-1:1999.
The cardboard material according to claim 1 or 2, characterized in that. The step repetition rate is 1.5 [times] or more,
The plane compressive strength is 170 [kPa] or more.
The cardboard material according to claim 9, wherein: The double-sided cardboard is an A flute
The cardboard material according to any one of claims 1 to 10, wherein A cardboard box using the cardboard material according to any one of claims 1 to 11 .

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