JP2016165883A - Reinforcement paper-made board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance bending strength of a paper-made board without largely increasing thickness.SOLUTION: A paper-made board is composed of a board shaped structure 10 and cardboard layers 1, 2, and 3 adhered to the board shaped structure. The board shaped structure includes: a core 4; and a first liner paper layer 2 and a second liner paper layer 3 which are adhered to the core so as to hold the core in a sandwich manner. In the paper-made board, the cardboard layers are adhered to the first liner paper layer, thickness of the board-shaped structure is about 15 to about 40 mm, thickness of the first liner paper layer and the second liner paper layer is about 0.5 to about 1.2 mm, respectively and independently, and thickness of the cardboard layers is about 1 to about 4 mm.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to a reinforced paper board and a method for manufacturing the same.

  Paper boards have been used for a wide range of applications such as packaging materials and furniture core materials because they are lightweight and have excellent heat insulation and soundproofing properties. In such a paper board structure, a reinforcing core such as a honeycomb core is sandwiched between two paper layers so as to have a compressive strength, tensile strength, bending strength, etc. in the thickness direction of the board. Various strengths are enhanced.

  In recent years, the use of paper, which is a resource-recycling material that can reproduce raw materials, has attracted a great deal of attention as a countermeasure to environmental problems. In particular, if non-paper boards such as polystyrene boards, plastic boards, and wood boards that are currently used can be replaced with resource-recycling paper boards, there is a possibility of greatly contributing to environmental problems.

  However, in order to replace a non-paper board with a paper board, it is necessary to further increase the strength of the paper board without significantly increasing the cost.

  Conventionally, the thickness of the board is increased in the art to load more weight on the paper board or to withstand higher loads. However, since the volume occupied by the board itself with respect to the load is large and the use efficiency of the space is poor, the inventor considered that this is not preferable. Therefore, as a result of intensive studies in view of the above problems, the inventor has adhered an additional paperboard layer only on one side to the two liner paper layers sandwiching the core of the paper board in a sandwich-like manner. It has been found that by increasing only the paper layer on one side of the board, the bending strength can be effectively increased to a level comparable to that of a wood board without greatly increasing the thickness of the entire board. As this additional paperboard layer, inexpensive paper such as used paper and recycled paper can be used, so that a paper board having strong bending strength can be manufactured at low cost. In addition, since high strength can be obtained without increasing the thickness, the paper board of the present invention is particularly suitable for use in a transportation pallet where an increase in thickness directly leads to an increase in transportation costs.

  The inventors have also determined that the bending strength of the liner paper layer to which the additional paperboard layer of the two liner paper layers sandwiching the core of the paper board is sandwiched is greater than the bending strength of the other liner paper layer. It was found that the bending strength of the entire board can be efficiently increased by making it weak. Actually, since one of the two liner paper layers sandwiching the core in a sandwich-like manner can be used, it can be manufactured at a low cost because a paper having a bending strength of about a temporary fixing can be used.

  In this paper board, the strength of the board can be freely adjusted by selecting an additional paperboard layer. Accordingly, it is possible to freely adjust the strength of the paper board without having to change the equipment and settings of the production line for bonding the core and the two liner paper layers sandwiching the core.

The present invention also provides the following items.
(Item 1)
A paper board comprising a board-like structure and a paperboard layer bonded to the board-like structure,
The board-like structure includes a core, and a first liner paper layer and a second liner paper layer bonded to the core so as to sandwich the core therebetween.
The paperboard layer is bonded to the first liner paper layer;
The board-like structure has a thickness of about 15 mm to about 40 mm,
The thicknesses of the first liner paper layer and the second liner paper layer are each independently about 0.5 mm to about 1.2 mm;
The thickness of the paperboard layer is from about 1 mm to about 4 mm;
Paper board.
(Item 2)
Item 2. The paper board according to Item 1, wherein the thickness of the board-like structure is about 15 mm or more and less than about 20 mm, and the bending strength of the paper board is about 450 kg / m or more.
(Item 3)
Item 2. The paper board according to Item 1, wherein the thickness of the board-like structure is about 20 mm or more and less than about 30 mm, and the bending strength of the paper board is about 650 kg / m or more.
(Item 4)
Item 2. The paper board according to Item 1, wherein the board-like structure has a thickness of about 30 mm or more and about 40 mm or less, and the bending strength of the paper board is about 950 kg / m or more.
(Item 5)
Item 5. The paper board according to any one of items 1 to 4, wherein the thickness of the paperboard layer is about 1 mm to about 2 mm.
(Item 6)
Item 6. The paper board according to any one of items 1 to 5, wherein the thickness of the paperboard layer is about 20% or less of the thickness of the board-like structure.
(Item 7)
Item 7. The paper board according to Item 6, wherein the thickness of the paperboard layer is about 15% or less of the thickness of the board-like structure.
(Item 8)
Item 8. The paper board according to Item 7, wherein the thickness of the paperboard layer is about 10% or less of the thickness of the board-like structure.
(Item 9)
Item 9. The paper board according to any one of Items 1 to 8, wherein the core has a shoulder portion at an adhesive surface with the first liner paper layer or the second liner paper layer.
(Item 10)
A pallet including the paper board according to any one of items 1 to 9.
(Item 11)
A form including the paper board according to any one of items 1 to 9.
(Item 12)
A method for producing a paper board having a predetermined bending strength,
The core is bonded to the first liner paper layer and the second liner paper layer so that the core is sandwiched between the first liner paper layer and the second liner paper layer, and is about 15 mm. Forming a board-like structure of about 40 mm;
Selecting a paperboard layer of about 1 mm to about 4 mm according to the predetermined bending strength;
Adhering the paperboard layer to the surface of the first liner paper layer, wherein the first liner paper layer and the second liner paper layer are each independently about 0.5 mm to about 1. The manufacturing method which is 2 mm.

  According to the present invention, the bending strength of a paper board can be greatly increased to a level comparable to that of a wood board. As a result, non-paper boards such as polystyrene boards, plastic boards, and wood boards can be replaced with resource-recycling paper boards, which can greatly contribute to environmental problems.

  In particular, the paper board provided by the present invention can achieve a bending strength comparable to that of the above-described wood board at low cost, and is suitable for use as, for example, a pallet or a transportation material. And since all the paper boards of this invention are recyclable, it can contribute greatly to an environmental problem by reducing the usage-amount of wood resources.

  The paper board of the present invention can achieve high strength without increasing the thickness. Therefore, the paper board of the present invention is suitable for use as a transportation pallet that requires a high load capacity and a formwork that requires a high load capacity. Particularly suitable for use on transport pallets. Generally, paper products have a large volume with respect to weight, and the ratio of transportation costs to the product unit price is large. Therefore, reducing the thickness (volume) of paper boards directly leads to a reduction in transportation costs. .

  Also, for example, compared to a paper board using the same paper cardboard instead of an additional paperboard layer, the paper board of the present invention has no bending strength variation depending on the direction, and high bending in any direction. The strength can be achieved and / or the decrease in bending strength due to humidity is small (corrugated cardboard has a great difference in bending strength between the vertical and horizontal lines due to its structure). From these characteristics, the paper board of the present invention is particularly suitable for use on a transportation pallet.

FIG. 1A is a perspective view of a paper board of the present invention. FIG. 1B is a front view of the paper board of the present invention. FIG. 2A is a perspective view showing a state in which a part of the first paper layer and the third paper layer of the paper board of the present invention is removed to expose the surface of the core. FIG. 2B is a perspective view of the paper board of the present invention with a portion of the first paper layer and the third paper layer removed to expose an alternative core surface. FIG. 3A shows a process of providing a paper laminate in the process of manufacturing the paper board of the present invention. FIG. 3B shows a cutting process of the paper laminate and a core forming process in the manufacturing process of the paper board of the present invention. FIG. 3C shows the sandwich-like bonding process of the core with the first paper layer and the second paper layer in the manufacturing process of the paper board of the present invention. FIG. 3D shows an adhesion process of the paper layer 3 to the paper layer 1 in the manufacturing process of the paper board of the present invention. FIG. 4 is a schematic diagram showing a bending test in Examples. FIG. 5A shows the appearance of the core component according to a preferred cutting method. FIG. 5B shows a state of cutting the core constituent member according to a preferable cutting method. FIG. 5C shows the state after cutting of the core component according to a preferred cutting method. FIG. 6A shows the state of adhesion between the cut surface of the core component and the liner layer according to a preferred cutting method. FIG. 6B shows an adhesion state between the cut surface of the core member and the liner layer according to a general cutting method. FIG. 7A shows an example of a cutting blade that can be used in a preferred cutting method. FIG. 7B shows an example of a cutting blade that can be used in a preferred cutting method. FIG. 7C is a side view showing an example of a general cutting blade. FIG. 7D is a perspective view showing an example of a general cutting blade. FIG. 8A is a schematic diagram showing the cutting of the core component by a preferred cutting method. FIG. 8B is a schematic diagram showing the cutting of the core constituent member by a general cutting blade. FIG. 9A shows the state of the cut surface of the core component according to a preferred cutting method. FIG. 9B shows a state of a cut surface of a core constituent member that is an object to be cut by a general cutting blade.

  The invention will now be described, by way of example, with reference to the accompanying drawings, where appropriate. Throughout this specification, it should be understood that the singular forms also include the plural concept unless specifically stated otherwise. In addition, it is to be understood that the terms used in the present specification are used in the meaning normally used in the art unless otherwise specified. Thus, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

  In accordance with the present invention, the two board layers sandwiching the core of the paper board in a sandwich-like manner are bonded with an additional paperboard layer only on one side, and only the paper layer on one side of the core is made thicker. The overall bending strength can be effectively increased to a level comparable to that of wood boards. As this additional paperboard layer, inexpensive paper such as used paper and recycled paper can be used, so that a paper board having strong bending strength can be manufactured at low cost.

  Moreover, according to this invention, high intensity | strength can be achieved, without increasing thickness in a paper board. Specifically, a bending strength that could not be achieved in the past can be achieved by simply bonding a paperboard layer of about 1 mm to 4 mm to a core sandwiched between two liner paper layers having a thickness of about 15 mm to 40 mm. . The present inventor has unexpectedly realized a paper board that can withstand a load of 400 kg or more, which could not be achieved by the present invention, with a board thickness of, for example, about 15 to 20 mm.

  Furthermore, according to the present invention, the bending strength of the paper board structure can be increased greatly without increasing the cost. More specifically, among the two paper layers sandwiching the core of the paper board structure in a sandwich-like manner, the basis weight of the paper layer to which the additional paper layer is bonded is more than the basis weight of the other paper layer. By making it small, the bending strength of the whole board structure can be increased greatly. Actually, since one of the two paper layers sandwiching the core in a sandwich-like manner can be used, it can be manufactured at a low cost because a paper having a bending strength of about a temporary fastening can be used.

(Definition)
In the present specification, “paper” is used in its general meaning, and refers to any substance in which plant fibers are dispersed in water and thinly spread on a flat surface and dehydrated and dried.

  As used herein, “core” refers to any structure that provides bending strength to a paper board structure.

  In this specification, “corrugated cardboard” is a paper member in which a liner is bonded to one or both sides of a corrugated core paper, and the space formed by the core paper and the liner is the plane of the liner. The one that extends in the direction. “Corrugated cardboard” includes single-sided cardboard with a liner attached to one side of a core paper, double-sided cardboard with a liner attached to the top of a single-sided cardboard core base paper, and a single-sided cardboard core on one side of a double-sided cardboard Examples thereof include, but are not limited to, a combined double-sided cardboard and a double-sided cardboard in which a core portion of a single-sided cardboard is further bonded to one side of the double-sided cardboard.

  In the present specification, the “horizontal eye” of the cardboard means a direction substantially parallel to the direction in which the space formed by the core paper of the cardboard and the liner extends, and the “longitudinal” of the cardboard means the core of the cardboard. A direction substantially perpendicular to the direction in which the space formed by the paper and the liner extends.

  In this specification, the “board-like structure” is a structure formed by sandwiching a core between two liner paper layers in a sandwich-like manner, and is formed by the core and two liner paper layers. The structure in which the space to be extended extends in the thickness direction of the structure. Therefore, it should be noted that the board-like structure in the present invention is clearly different from the cardboard in which the space formed by the core paper and the liner extends in the planar direction of the liner.

  In this specification, “paper board” refers to a paper structure in which an additional paperboard layer is provided on the board-like structure.

In this specification, “basis weight” refers to the weight per 1 m ^{2 of} paper.

  In this specification, “winding is possible” means that it can be rolled on a core having a diameter of about 110 mm in a paper winder. The “rollable” paper in the present invention may be a general web that is rolled and distributed as a product. More specifically, the “rollable” paper in the present invention may be paper that can be wound into a roll having a thickness of about 1.2 mm or less.

  In this specification, “unwinding” means that a roll is attached to the paper winder and cannot be rolled in the paper winder. The “non-rollable” paper in the present invention may be a general lithographic paper distributed as a product in a sheet form. More specifically, the “non-rollable” paper in the present invention may be paper having a thickness of about 1.0 mm or more and cannot be wound into a roll.

  In this specification, “liner paper layer” or “liner paper” refers to a paper layer sandwiching cores in a sandwich-like manner. The liner paper layer in this specification does not contain substantial space inside. Accordingly, the liner paper layer herein does not include cardboard. In certain embodiments, the liner paper layer refers to paper of about 0.5 mm to about 1.2 mm. In a preferred embodiment, the liner paper layer refers to about 0.5 mm to about 1.2 mm of paper that can be wound.

  As used herein, “paperboard layer” or “paperboard” refers to a paper layer added to a board formed by sandwiching a core between at least two liner paper layers. The paperboard layer in this specification does not include substantial space inside. Accordingly, the paperboard layer herein does not include cardboard. In some embodiments, it refers to about 1 mm to about 4 mm of paper. In a preferred embodiment, the paperboard layer refers to about 1 mm to about 4 mm of paper that cannot be wound.

  In this specification, the “bending strength” of a board is a value (Kg / m) obtained by converting a measured value measured by a single point concentrated load of 400 mm span at a speed of 10 mm / min into an evenly distributed load converted to 1 m width. Say. This distance of 400 mm is a general distance between the two arms of the forklift. Note that the conversion from the single point concentrated load to the uniformly distributed load is achieved by doubling the measured value of the single point concentrated load.

  In the present specification, the “shoulder portion” refers to a region where the fiber density is changed from before cutting by cutting, which is formed on the cut surface of paper cut by a cutting blade having a wedge-shaped cutting edge. On the cut surface of the paper cut by the wedge-shaped cutting edge of the cutting blade, the fibers spread, the fiber density decreases, and the area increases.

  In the present specification, “about” refers to a range of ± 10% of the following number.

(Description of Preferred Embodiment)
The embodiments provided below are provided for a better understanding of the present invention, and the scope of the present invention should not be limited to the following description. It will be apparent to those skilled in the art that appropriate modifications can be made within the scope of the present invention with reference to the description in the present specification.

  As shown in FIG. 1A (a perspective view of the paper board of the present invention) and FIG. 1B (a front view of the paper board of the present invention), the paper board 10 of the present invention has three paper layers (first liner). A board composed of a paper layer 1, a second liner paper layer 2 and a third paperboard layer 3) and a core 4. The liner paper layer 1 and the liner paper layer 2 and the core 4 are bonded to each other so that the liner paper layer 1 and the liner paper layer 2 sandwich the core 4 in a sandwich manner. The third paperboard layer 3 is bonded to the surface of the liner paper layer 1 (the surface opposite to the bonding surface with the core 4).

  In a typical preferred embodiment, in the production of the paper board 10 of the present invention, the sandwich-like adhesion of the liner paper layer 1 and the liner paper layer 2 to the core 4 is obtained by winding the liner paper layer 1 into a roll. The liner paper layer 1 is fed out from the roll body, and the liner paper layer 2 is fed out from the other roll body obtained by winding the liner paper layer 2 into a roll, and the liner paper layer 1 is adhered to one surface of the core 4. And it can be performed by adhering the liner paper layer 2 to the other surface of the core 4. Therefore, in this embodiment, both the liner paper layer 1 and the liner paper layer 2 must be rewound paper products.

  In one embodiment, the features of the present invention are comparable to a timber board by further reinforcing the structure in which the core 4 is sandwiched between the liner paper layer 1 and the liner paper layer 2 with the paperboard layer 3. It is in the point which can raise the bending strength of a board to such an extent. More specifically, for example, when the paperboard layer 3 is bonded to the liner paper layer 1, the sum of the basis weight of the liner paper layer 1 and the basis weight of the paperboard layer 3 is larger than the basis weight of the liner paper layer 2. Thus, each paper layer is selected. As this additional paperboard layer 3, inexpensive paper such as used paper or recycled paper can be used, so that the cost does not increase.

  In one embodiment, the feature of the present invention is that the structure in which the core 4 is sandwiched between the liner paper layers 1 and 2 is further reinforced by the paperboard layer 3 without increasing the overall thickness of the board. It exists in the point which can raise bending strength efficiently. Therefore, the paper board of the present invention can realize a high load capacity and / or a high load resistance without the board itself having a large volume. Further, in the paper board of the present invention, no corrugated cardboard is used for either the liner paper layer or the paperboard layer, so there is no variation in direction in the bending strength of the board and / or the decrease in bending strength due to humidity is small. . From these features, the paper board of the present invention is suitable for use on pallets, molds, and the like, and is particularly suitable for use on pallets where an increase in the thickness of the board itself is directly linked to transportation costs. 1A and 1B and other drawings, the liner paper layer 1 is thinner than the liner paper layer 2, but the present invention is not limited to this, and the liner paper layer 1 is not limited thereto. The liner paper layer 2 may have the same thickness, or the liner paper layer 1 may be thicker than the liner paper layer 2.

  In one embodiment, a further feature of the present invention is the use of a basis weight paper (preferably a web) that is less than the basis weight of the liner paper layer 2 as the liner paper layer 1. As described above, the present inventors enhance the overall bending strength of the paper board 10 by reinforcing the structure in which the core is sandwiched between two paper layers with an additional paperboard layer 3. In this case, the basis weight of the liner paper layer 1 is not the same as the basis weight of the liner paper layer 2 but rather is made smaller so that the paper board 10 is bonded by bonding the paperboard layer 3. It was unexpectedly found that the bending strength was dramatically improved (see particularly Table 2 in the following examples). Further, since a paper having a small basis weight may be used as the liner paper layer 1, the cost can be reduced as compared with a case where a paper having a basis weight similar to that of the liner paper layer 2 is used. In this field, generally, the smaller the basis weight, the cheaper the paper. Actually, since a paper having a basis weight of about a temporary fixing can be used as the liner paper layer 1, it can be manufactured at low cost. Usually, in order to increase the bending strength of the paper board 10, there is no reason to increase or decrease the basis weight between the liner paper layer 1 and the liner paper layer 2, and those skilled in the art will naturally understand the liner paper. The basis weight of layer 1 and liner paper layer 2 should be comparable. Therefore, the inventors' discovery was completely unexpected. Further, by using a paper having a small basis weight and / or a thin paper as the liner paper layer 1, it is possible to increase the production speed of the board structure and to improve the productivity.

Under the condition that the sum of the basis weight of the liner paper layer 1 and the basis weight of the paperboard layer 3 is larger than the basis weight of the liner paper layer 2, the liner paper layer 1 has an arbitrary thickness depending on the application. The thing of a weight and a basic weight can be selected. In a preferred embodiment, the basis weight of the liner paper layer 1 is less than the basis weight of the liner paper layer 2. For example, the basis weight of the liner paper layer 1 is about 210 g / m ² to about 900 g / m ² , and preferably about 500 g / m ² to about 700 g / m ² . In general, when the paper layer is made of the same material, the basis weight of the paper layer depends on the thickness. Therefore, the thickness of the liner paper layer 1 can be thinner than the thickness of the liner paper layer 2. In general, paper products have a large volume with respect to weight, and the ratio of transportation costs to the product unit price is large. Therefore, by using thin paper as the liner paper layer 1, the thickness (volume) of the paper board is further reduced. Thus, transportation costs can be reduced. The liner paper layer 1 has a thickness of, for example, about 0.3 mm to about 1.2 mm, more preferably about 0.7 mm to about 1.2 mm, and preferably about 0.7 mm to about 1.0 mm. In a preferred embodiment in which the basis weight of the liner paper layer 1 is smaller than the basis weight of the liner paper layer 2, the liner paper layer 1 may be of a strength that is temporary enough to fix the structure of the core 4. Good. In general, the basis weight is 0.25 mm = about 180 g / m ² .

Under the condition that the basis weight of the liner paper layer 1 and the basis weight of the paperboard layer 3 is larger than the basis weight of the liner paper layer 2, the liner paper layer 2 has any thickness depending on the application. The thing of a weight and a basic weight can be selected. In a preferred embodiment, the basis weight of the liner paper layer 2 is greater than the basis weight of the liner paper layer 1. For example, the basis weight of the liner paper layer 2 is about 210 g / m ² to about 900 g / m ² , and preferably about 500 g / m ² to about 700 g / m ² . The thickness of the liner paper layer 2 is, for example, about 0.3 mm to about 1.2 mm, and preferably about 0.5 mm to about 1.0 mm.

Both liner paper layer 1 and liner paper layer 2 are preferably rollable web products. As the paper of this liner paper layer, for example, paper for cores (typical basis weight 120 g / m ^{2 to} 160 g / m ² ) or paper for paper tube paper (typical basis weight 400 g / m ² to 800 g / m ² ) can be used.

The paperboard layer 3 is adhered to the surface of the linerpaper layer 1 at the same time as or after the linerpaper layer 1 and the linerpaper layer 2 are adhered to the core 4. In a preferred embodiment, the bonding of the paperboard layer 3 takes place after the bonding of the liner paper layer 1 and the liner paper layer 2 to the core 4 using a winder. Therefore, the paperboard layer 3 does not need to be a paper that can be wound, and can be a paper that cannot be wound, typically a lithographic paper, or of course a paper that has been cut off. As described above, the paperboard layer 3 may be wound or not, so that a wide variety of papers can be used. Therefore, it is possible to reduce the manufacturing cost of the paper board 10 by using already used planographic paper and used paper. In a preferred embodiment, the thickness of the paperboard layer 3 is about 1 mm to about 4 mm. The paperboard layer 3 is, for example, paper for paper tube paper having a thickness of about 1 mm (typical basis weight 700 g / m ² ) or paper obtained by bonding 2 to 4 sheets thereof. When four sheets of paper having a basis weight of 700 g / m ² are bonded, the basis weight is about 3,150 g / m ² including the weight of the paste for bonding. The paper layer 3 may be composed of a single layer of paper, or may be composed of a plurality of layers of paper.

  The board-like structure (liner paper layers 1 and 2 and core 4) of the present invention has a thickness of about 15 mm to about 40 mm, more preferably about 15 mm to about 30 mm, and more preferably about 20 mm to about 30 mm. It is. The present inventor is able to greatly increase the bending strength without greatly increasing the thickness of the entire board by additionally providing a board-like layer of about 1 mm to about 4 mm to the board-like structure in this range. I found it unexpectedly.

  In a typical embodiment, the basis weight of the layer where the liner paper layer 1 and the paperboard layer 3 are bonded is greater than the basis weight of the liner paper layer 2. In a preferred embodiment, the liner paper layer 1 and the liner paper layer 2 are paper of the same thickness and / or basis weight.

  The paper board 10 of the present invention may be used with the paperboard layer 3 facing up, or may be used with the paperboard layer 3 facing down. When a load is applied to the paperboard layer 3 side of the paper board 10, a compression force is applied to the paperboard layer 3 side and a tensile force is applied to the opposite liner paper layer 2 side, but the liner paper layer 1 and the paperboard layer 3 are compressed. By resisting the force, the paper board 10 is given a strong bending strength. Further, when a load is applied to the liner paper layer 2 side of the paper board 10, a compression force is applied to the liner paper layer 2 side and a tensile force is applied to the opposite paperboard layer 3 side. When 3 opposes the tensile force, the paper board 10 is also given a strong bending strength.

  In a preferred embodiment, the paper board of the present invention is used as a transportation pallet. When a paper board is used as the transportation pallet, the object to be transported may be supported on the liner paper layer 2 side or on the paperboard layer 3 side. Although not limiting the present invention, when transporting an object that intensively loads a part of a paper board, it is preferable to support the object with the paperboard layer 3 side up, In particular, when a forklift is used to load an object that loads an almost entire surface of a paper board with an average, the bending load applies a compressive force to the lower side, so the liner with the paperboard layer 3 side down. The object is preferably supported by the paper layer 2.

  Generally, in a transportation pallet, a large bending strength is required on the lower side of the pallet board (side held by a forklift claw). Therefore, when the paper board structure of the present invention is used as a transportation pallet, by making the paperboard layer 3 on the lower side (side held by the forklift claw), the transportation board having a desired bending strength can be efficiently obtained. It can be a pallet. In addition, when the required conditions are different between the upper side and the lower side of the board as in the pallet, the required condition can be achieved efficiently by reinforcing one side as in the paper board of the present invention. Can do.

  2A and 2B show a specific structure of the core 4 used in the paper board 10 of the present invention. FIG. 2A is a perspective view showing a state in which a part of the liner paper layer and the paperboard layer of the paper board of the present invention is removed to expose the surface of the core. The most preferred core structure of the present invention is shown in FIG. 2A. In FIG. 2A, the core 4 is a core unit composed of a paper core 21 shaped so that a large number of, for example, sinusoidal waveforms are arranged, and a paper liner 22 joined to the curved convex portion on one side thereof. It is formed by arranging a plurality of stages 23 into a flat shape.

  The shape of the core material 21 may be V-shaped, U-shaped, or trapezoidal in addition to the corrugated shape as described above. Alternatively, as shown in FIG. 2B, the core 4 may be a honeycomb-shaped core in which a large number of hexagonal column spaces 24 are formed.

  The bending strength of the paper board 10 increases as the height H of the core 4 increases. The height H of the core 4 can be appropriately determined by a person skilled in the art depending on the use of the paper board 10, but typically, the thickness of the board-like structure is about 15 to about 40 mm. Typically about 20 mm, about 30 mm, or about 40 mm.

The basis weight of the paper forming the core 4 can be appropriately determined by those skilled in the art depending on the application, and is, for example, about 160 g / m ² to about 280 g / m ² .

  In FIG. 3, a typical method for manufacturing the paper board 10 will be described. First, a paper laminate 40 having a height higher than the final height 4 of the core 4 is produced (FIG. 3A). The laminated body 40 is cut at a thickness of H to form a core 4 (FIG. 3B), and the core 4 is sandwiched between liner paper layers 1 and 2 and bonded (FIG. 3C). Next, the paperboard layer 3 is adhered to the surface of the liner paper layer 1 (FIG. 3D) to obtain the paper board 10 of the present invention.

  The paper board 10 can have any size depending on the application, and examples thereof include 1,100 mm × 1,100 mm, 800 mm × 1,000 mm, 1,000 mm × 1,200 mm, and the like. It is not limited. The paper board 10 may be formed into a desired size after the core 4 is sandwiched between the liner paper layers 1 and 2 and before the paperboard layer 3 is bonded (ie, in the state shown in FIG. 3C). It may be performed after the paperboard layer 3 is bonded to the liner paper layer 1 (that is, in the state of FIG. 3D).

  In the present invention, the adhesive for adhesion may be any paper adhesive. One skilled in the art can readily select an appropriate adhesive for the production of the paper board 10 of the present invention. A typical corrugated adhesive is a starch adhesive, and contains starch, alkali (for example, caustic soda), boron compound (for example, borax), water, and the like as components.

  The present invention provides a paper board-like structure having a bending strength that is comparable to that of a timber board, the bending strength of which is reinforced by the reinforcement of the paper layer 3. Since the paperboard layer 3 can be selected from a wide variety of papers (for example, used paper), inexpensive paper can be used. Therefore, the cost is not increased significantly by the reinforcement with the paperboard layer 3. Furthermore, the paper board structure finally obtained has a strength comparable to that of a wood board, but is made of paper, so that it can be completely recycled after use and contributes greatly to environmental problems.

  In addition, by selecting the type of the paperboard layer 3, the strength of the paper board structure can be freely adjusted according to the application and predetermined strength. Conventionally, the strength of the paper board has been adjusted by changing the structure of the core 4 and the strength of the liner paper layers 1 and 2, particularly by mainly changing the original size of the core. However, changing the structure of the core 4 and the strength of the liner paper layers 1 and 2 requires changing each device and its setting in the automatic production line each time. This is time-consuming and causes a loss every time it is changed, which is a heavy burden on the manufacturer. On the other hand, in the present invention, the strength can be freely adjusted simply by changing the type of the paperboard layer 3 to be bonded to the liner paper layer 1, so that various devices in the production line and their settings are changed according to the strength. There is no need to do. As a result, manufacturers can manufacture paper boards with various strengths without having to change the equipment and settings of the production line for each paper board strength. For example, a plurality of types of used paper are prepared as the paperboard layer 3, and an appropriate used paper having a basis weight or a thickness capable of achieving a desired bending strength is selected from among them, and sandwiched between liner paper layers 1 and 2. By adhering the selected paperboard layer 3 to the liner paper layer 1 side of the core formed, a paper board having a desired bending strength can be provided very simply.

  In addition, in the paper board of the present invention, inexpensive paper can be used as the liner paper layer 1 by using paper with a small basis weight as the liner paper layer 1. Further, by using a paper having a small basis weight and / or a thin paper as the liner paper layer 1, it is possible to increase the production speed of the board structure and to improve the productivity.

(Board thickness and bending strength)
The present invention is typically characterized by greatly increasing the bending strength without greatly increasing the thickness of the board. As is clear from reference to the data in Table 4 to be described later, when a bending strength of, for example, 1000 kg / m is required, a board-like structure of 60 mm (in the case of the board-like structure of Table 4 with 60 mm and no paperboard) is now available. Bend strength of 1144 kg / m), or two board-like structures are stacked and bonded together (for example, two 30 mm board-like structures are bonded together, or a 20 mm board-like structure and A paper board having a strength capable of withstanding such a weight load is provided by bonding to a 30 mm board-like structure. However, the thicker the board-like structure, the worse the thermal efficiency for heating and bonding the liner paper layer to the core during manufacture. In addition, a structure in which two or more board-like structures are stacked has a complicated manufacturing process and wastes the paper used for the two liner paper layers on the surface where the two are bonded, which is inefficient. . However, according to the present invention, a bending strength of 1298 kg / m is achieved by adhering 1 mm paperboard to a 30 mm boardlike structure (see the case of 30 mm boardlike structure and 1 mm paperboard in Table 4). The bending strength of 1000 kg can be achieved while the board is 31 mm thick. It should be noted that a thickness of 60 mm is currently required, whereas the present invention achieves the same or higher strength with about half that thickness. For example, the bending strength that has been achieved by pasting together a board-like structure having a thickness of 40 mm to 60 mm or two board-like structures having a thickness of 30 mm is 1 to 1 for a board-like structure having a thickness of 30 mm. This can be achieved only by combining about 4 mm paperboard.

  In one embodiment of the invention, the thickness of the board-like structure is about 15-40 mm and the thickness of the additional paperboard layer is about 1 mm to about 4 mm. In a preferred embodiment, the thickness of the paperboard layer is from about 1 mm to about 3 mm, and in a more preferred embodiment, the thickness of the paperboard layer is from about 1 mm to about 2 mm.

  In one embodiment, the present invention achieves a bending strength of 450 kg / m with a small thickness compared to the prior art. Specifically, the present invention is a paper board in which a board of about 1 mm to 4 mm is bonded to a board-like structure of about 15 mm or more and less than 20 mm, and has a bending strength of about 450 kg / m or more. I will provide a. In a more preferred embodiment, the present invention is a paper board in which a board of about 1 mm to about 4 mm is bonded to a board-like structure of about 15 mm or more and less than 20 mm, and the bending strength is about 500 kg / m or more. Provide paper board. In a more preferred embodiment, the present invention is a paper board in which a board of about 1 mm to about 4 mm is bonded to a board-like structure of about 15 mm to less than 20 mm, and the bending strength is about 550 kg / m or more. Provide paper board. For example, according to the inventor's previous research and development, a board having a bending strength of 550 kg / m can sufficiently withstand a load of 400 kg.

  In another embodiment, the present invention achieves a bending strength of 650 kg / m with a small thickness compared to the prior art. Specifically, the present invention is a paper board in which a board of about 1 mm to 4 mm is bonded to a board-like structure of about 20 mm or more and less than 30 mm, and has a bending strength of about 650 kg / m or more. I will provide a. In a more preferred embodiment, the present invention is a paper board in which a board of about 1 mm to about 4 mm is bonded to a board-like structure of about 20 mm or more and less than 30 mm, and the bending strength is about 700 kg / m or more. Provide paper board. In a more preferred embodiment, the present invention is a paper board in which a board of about 1 mm to about 4 mm is bonded to a board-like structure of about 20 mm or more and less than 30 mm, and the bending strength is about 750 kg / m or more. Provide paper board. For example, according to the inventor's previous research and development, a board having a bending strength of 700 kg / m can sufficiently withstand a load of 500 kg.

  In another embodiment, the present invention achieves a bending strength of 950 kg / m with a small thickness compared to the prior art. Specifically, the present invention relates to a paper board in which a board of about 1 mm to 4 mm is bonded to a board-like structure of about 30 mm to 40 mm, and has a bending strength of about 950 kg / m or more. I will provide a. In a more preferred embodiment, the present invention is a paper board in which a board of about 1 mm to about 4 mm is bonded to a board-like structure of about 30 mm to 40 mm, and the bending strength is about 1000 kg / m or more. Provide paper board. In a more preferred embodiment, the present invention is a paper board in which a board of about 1 mm to about 4 mm is bonded to a board-like structure of about 30 mm to 40 mm, and the bending strength is about 1100 kg / m or more. Provide paper board. For example, according to the present inventor's research and development, a board having a bending strength of 950 kg / m can sufficiently withstand a load of 700 kg.

  In another embodiment, the present invention achieves a bending strength of 950 kg / m with a small thickness compared to the prior art. Specifically, the present invention is a paper board in which a board of about 1 mm to 4 mm is bonded to a board-like structure of about 30 mm or more and less than 40 mm, and has a bending strength of about 950 kg / m or more. I will provide a. In a more preferred embodiment, the present invention is a paper board in which a board of about 1 mm to about 4 mm is bonded to a board-like structure of about 30 mm or more and less than 40 mm, and the bending strength is about 1000 kg / m or more. Provide paper board. In a more preferred embodiment, the present invention is a paper board in which a board of about 1 mm to about 4 mm is bonded to a board-like structure of about 30 mm or more and less than 40 mm, and the bending strength is about 1100 kg / m or more. Provide paper board.

  In preferred embodiments, the thickness of the additional paperboard layer is no more than about 20% of the thickness of the board-like structure. In a more preferred embodiment, the thickness of the additional paperboard layer is no more than about 15% of the thickness of the board-like structure. In a further preferred embodiment, the thickness of the additional paperboard layer is no more than about 10% of the thickness of the board-like structure. In a further preferred embodiment, the thickness of the additional paperboard layer is no more than about 5% of the thickness of the board-like structure.

(Use)
The paper board of the present invention can be used in place of wood board in various applications where wood board is used. Examples of the use of the paper board of the present invention include, but are not limited to, pallets and molds.

Pallet The paper board of the present invention is particularly suitable for use on a transportation pallet. Generally, paper products have a large volume with respect to weight, and the ratio of transportation costs to the product unit price is large. Therefore, reducing the thickness (volume) of paper boards directly leads to a reduction in transportation costs. .

  Also, for example, compared to a paper board using cardboard instead of an additional paperboard layer, the paper board of the present invention has a variation in bending strength due to a structurally inevitable direction when using cardboard. In addition, a high bending strength can be achieved in any direction and / or a decrease in bending strength due to humidity is small. Also from these features, the paper board of the present invention is suitable for use on a transportation pallet.

  In fact, when a product is transported using the paper board of the present invention on a transportation pallet, the recipient of the product can easily discard or recycle the paper board as the transportation pallet. You can also. Processing wood is more time-consuming and difficult than paper processing, so when using wood boards for transportation pallets, product recipients cannot easily handle the pallets, and in some cases There was even a return. Therefore, by using the paper board of the present invention, one-way efficient transportation that has not been achieved by transportation using wood board is achieved.

-Formwork Embodiment which applied the paper board of this invention to the formwork, for example, the formwork for concrete, is described.

  The entire surface of the paper board is preferably waterproofed. As a waterproofing method, a method of coating the resin film on the board surface by degassing the air in the bag with the board inserted into a bag-like resin film (for example, vinyl) is preferable. However, the waterproofing method is not limited to the above method, and for example, a paper board may be dipped in a water-resistant or water-repellent liquid such as paraffin wax or phenol resin to coat the surface.

  By waterproofing the entire surface of the paper board, it is possible to obtain excellent water resistance against rainwater and moisture contained during concrete placement.

  In particular, the method of coating the surface of the paper board by degassing the bag-shaped resin film to form a mold is coated with the resin film firmly attached to the surface of the mold, so that the strength of the paper board and The rigidity can be improved. Furthermore, the mold can be peeled off very easily from the cured concrete product with little force.

(Adhesion)
For adhesion between the core 4 and the liner paper layers 1 and 2, for example, an adhesion technique described in Japanese Patent Application No. 2015-43646 (the contents of which are incorporated herein by reference) can be used.

  As described above, in FIG. 3B, the laminated body 40 is cut at a height H to form the core 4. The manner of cutting the core 4 in the preferred embodiment will be described with further reference to FIGS. The core constituent member 400 is a piece of paper that forms the corrugation of the core 4. The core component member 400 is cut along the alternate long and short dash line C by the cutting blade 80 and adhered to the liner paper layers 1 and 2 along the cut surface at a substantially right angle. The wedge-shaped cutting edge of the cutting blade 80 is inserted into the core component member 400 that is the object to be cut, and as the cutting blade 80 is advanced, the core component member 400 is pushed and spread on both sides of the cutting edge to form the cutting surface 410. (See FIG. 5B and FIG. 5C. “Shoulder”). The core constituent member 400 in the vicinity of the cutting surface 410 is less likely to become paper dust when cut by the cutting blade, and still remains in the core constituent member 400 after cutting. As a result, in the cut surface 410, the fibers constituting the core constituent member 400 spread, the fiber density decreases, and the area increases (a “shoulder portion” is formed). It should be noted that the cut surface 410 does not indicate only a surface generated in the core component member 400 by cutting, but indicates a region where the fiber density has changed from before cutting by cutting.

  In FIG. 5A, a cross section of the core component member 400 (that is, a vertical cross section including the alternate long and short dash line C) when it is assumed that the core member 400 is clearly cut along the alternate long and short dash line C is a “virtual corresponding surface before cutting” in the present invention. It is clearly understood that the area of the bonding surface 410 is larger than the virtual corresponding surface before cutting.

  6A, another paper member 420 (specifically, the liner paper layer 1 or 2) is formed on the cut surface 410 of the core component 400 obtained by cutting with the cutting blade 80 as shown in FIGS. 5A to 5C. A state of bonding is shown. As described above, it is clear that the cutting surface 410 of the core component member 400 can secure a larger and larger bonding surface than the virtual corresponding surface before cutting by cutting with the cutting blade 80. Moreover, since the fiber density of the cut surface 410 is smaller than the fiber density of the core constituent member 400 before cutting, the adhesive easily penetrates and is easily entangled. Thereby, coupled with the fact that the area of the cut surface 410 of the core constituent member 400 is larger than the virtual corresponding surface before cutting, high adhesive strength is realized.

  FIG. 6B shows a state in which the core constituent member 400 cut by a general cutting blade and another paper member 420 are bonded to the cut surface. Compared to FIG. 6A, the cut surface of the core component 400 cut by a general cutting blade has a small adhesive surface, and the fiber density does not change in the cut surface and the core component 400 in the vicinity thereof. The adhesive is not easy to penetrate through the cut surface. Therefore, compared with the cut surface of the core component member 400 cut by the wedge-shaped cutting blade of the preferred embodiment, the adhesive force with another paper member 420 is weak.

  7A and 7B show the cutting blade for the preferred bonding method described above, and FIGS. 7C and 7D show the cutting blade for the general bonding method. The cutting blade (clean cut saw) shown in FIGS. 7A and 7B has a wedge-shaped tip, and the cutting edge is inserted into the workpiece, and as the cutting blade advances, the workpiece is pushed and spread on both sides of the cutting edge. Go. On the other hand, the general cutting blades (tip saws) shown in FIGS. 7C and 7D are formed by arranging a tip having a blade tip inclined to the left and right sides and a flat tip. Cut the object to be cut. Therefore, in the cutting with the cutting blades of FIGS. 7A and 7B, instead of removing the cut portion of the object to be cut, the paper is cut without changing the paper into paper dust by separating while cutting the cut portion. 7C and 7D, the cut portion of the object to be cut is scraped off and converted into paper dust and removed.

  FIG. 8A and FIG. 8B are schematic diagrams of cutting by a preferable cutting method and cutting by a general cutting method. FIG. 8A shows a state in which the core constituent member 400 is cut along the C with the cutting blade 80 according to the present invention. The wedge-shaped cutting blade 80 cuts the hatched portion of the core component member 400 along C while pushing it left and right. It will be understood that as the cutting edge of the cutting blade 80 is inserted into the workpiece and the cutting blade advances, the workpiece is pushed and spread on both sides of the cutting edge. FIG. 8B shows a state in which the core constituent member 400 is cut along the C with a general cutting blade 80 ′. The cutting blade 80 ′ is formed by arranging chips that are inclined to the left and right outwards and flat chips, and cuts the object to be cut while scraping the chip width (the hatched portion in FIG. 8B) to change it into paper dust. It will be understood. Note that the width of the cut (shaded portions in FIGS. 8A and 8B, respectively) is larger in FIG. 8B.

  FIG. 9A shows the state of the cut surface of the member that is the object to be cut by the above preferred cutting method, and FIG. 9B shows the state of the cut surface of the member that is the object to be cut by the general cutting method. The photographs shown in FIGS. 9A and 9B are the results of cutting the same member with different cutting blades. 9A and 9B, the cutting with the cutting blade (clean cut saw) shown in FIGS. 7A and 7B is more effective than the cutting with the general cutting blade (tip saw) shown in FIGS. 7C and 7D. It can be seen that the fibers spread on the surface, the fiber density is reduced, and the area is increased.

  That is, since the fiber density of the cut surface 410 of the core constituent member 400 is smaller than the fiber density of the core constituent member 400 before cutting by cutting with a cutting blade (clean cut saw) shown in FIGS. Can easily penetrate and the adhesive is easily entangled with the fiber, and high adhesive strength can be realized. Furthermore, since the cutting surface 410 of the core constituent member 400 becomes larger than the virtual corresponding surface before cutting of the core constituent member 400 by cutting, a wide adhesive surface can be secured and high adhesive strength can be realized.

  Adhesion using a preferred wedge-shaped cutting blade can achieve adhesion with high adhesive strength in the vertical direction between the core 4 and the liner layer 1 and / or 2. For example, when a large load is applied to the board, such as a paper pallet, a large load is also applied to the connecting portion between the core and the liner paper layer. However, when the core and liner paper layer are bonded together by the preferred bonding method as described above, the connection is stabilized, thereby achieving high bending strength of the entire board (see Example 7).

(Other embodiments)
The present invention has been described with reference to the preferred embodiments for easy understanding. Hereinafter, the present invention will be described based on examples. However, the above description and the following examples are provided only for the purpose of illustration and are not intended to limit the present invention. Accordingly, the scope of the present invention is not limited to the embodiments or examples specifically described in the present specification, but is limited only by the scope of the claims.

Example 1
As the paper board of the present invention, the basis weight of the liner paper layer 1 is 210 g / m ² (thickness: about 0.3 mm) and the basis weight of the liner paper layer 2 is 700 g / m ² (in accordance with the manufacturing method shown in FIGS. The thickness of the paperboard layer 3 is about 1.0 mm), the basis weight of the paper used for the core 4 is 220 g / m ² , and the thickness of the board-like structure (core 4, liner paper layers 1 and 2) is 30 mm. basis weight) 1 mm (about 700 g ^{/ m} 2) (example 1-1), 2 mm (about 1,400 g ^{/ m} 2) (example 1-2), and 4 mm (about 2,800 g ^{/ m} 2) (embodiment Three boards of Example 1-3) were manufactured. Specifically, after an adhesive mainly composed of starch is applied to the adhesive surfaces of the core 4 and the liner paper layer 1 and the liner paper layer 2 of the core 4 unrolled from the roll, the liner paper layer 1 and the liner paper layer 2 are applied. Were stacked on the bonding surface in a sandwich-like manner and pressed to bond both paper layers to the core. Thereafter, the paperboard layer 3 was bonded to the liner paper layer 1 using an aqueous vinyl acetate resin (for example, CN-135, Konishi Co., Ltd., Osaka, Japan) adhesive. Also, a board (reference example 1) without the paperboard layer 3 as a reference was manufactured.

(Example 2)
Similar to Example 1, as Example 2, the basis weight of the liner paper layer 1 is 700 g / m ² (thickness: about 1.0 mm), and the basis weight of the liner paper layer 2 is 700 g / m ² (thickness: about 1.0 mm). ), The basis weight of the paper used for the core 4 is 280 g / m ² , the thickness of the board-like structure is 30 mm, and the thickness of the paperboard layer 3 is 1 mm (about 700 g / m ² ) (Example 2-1) ) 3 boards of 2 mm (about 1,400 g / m ² ) (Example 2-2) and 4 mm (about 2,800 g / m ² ) (Example 2-3) were produced. A board (reference example 2) without the paperboard layer 3 as a reference was manufactured.

(Example 3)
As in Examples 1 and 2, as Example 3, the basis weight of the liner paper layer 1 is 700 g / m ² (thickness: about 1.0 mm), and the basis weight of the liner paper layer 2 is 700 g / m ² (thickness: about 1). 0.0 mm), the basis weight of the paper used for the core 4 is 280 g / m ² , the thickness of the board-like structure is 40 mm, and the thickness of the paperboard layer 3 is 1 mm (about 700 g / m ² ) (Example 3) -1) Three boards of 2 mm (about 1,400 g / m ² ) (Example 3-2) and 4 mm (about 2,800 g / m ² ) (Example 3-3) were produced. Further, a board (reference example 3) in which the paperboard layer 3 was not provided as a reference was manufactured.

Example 4
As Example 4, the basis weight of the liner paper layer 1 was 700 g / m ² (thickness: about 1.0 mm), the basis weight of the liner paper layer 2 was 700 g / m ² (thickness: about 1.0 mm), and the core 4 was used. The basis weight of the paper is 280 g / m ² , the thickness of the board-like structure is 50 mm, and the paperboard layer 3 has a thickness (basis weight) of 1 mm (about 700 g / m ² ) (Example 4-1), 2 mm (about 1, Three boards of 400 g / m ² ) (Example 4-2) and 4 mm (about 2,800 g / m ² ) (Example 4-3) were produced. Also, a board (reference example 4) in which the paperboard layer 3 was not provided as a reference was manufactured.

  In addition, the size of any of the above boards was 500 mm wide × 333 mm long. Further, as the liner paper layer 1 and the liner paper layer 2, a rolled paper was used, and as the paperboard layer 3, a lithographic paper was used.

  Below, the conditions of each board of Examples 1 to 4 are summarized in a table.

(Bending strength test)
About each structure of Table 1, the bending strength at the time of one point concentrated load was tested in Okayama Prefectural Industrial Technology Center. Before the test, each board was allowed to stand at 23 ° C. and a humidity of 50% for 24 hours. Thereafter, on December 3, 2014, the bending strength (Kg) of each structural body at 400 mm span was measured by a one-point concentrated load at a speed of 10 mm / min (load by the force point 30 in FIG. 4). The temperature at the start of the test (AM 10:05) was 12 ° C. and the humidity was 38%, and the temperature at the end of the test (AM 11:45) was 17 ° C. and the humidity was 33 percent. The distance between the fulcrum 31 and the fulcrum 32 in FIG. 4 was 400 mm.

  The table below summarizes the measured bending strength (Kg) of each board.

  Note that “multiple” in Table 2 indicates a multiple of change from the actual measured bending strength of the reference example. Examples 1-1 to 1-3 are from Reference Example 1, Examples 2-1 to 2-3 are from Reference Example 2, Examples 3-1 to 3-3 are from Reference Example 3. Examples 4-1 to 4-3 are the multiples of the change in the actual measured bending strength from Reference Example 4.

  As can be seen from Table 2, in all examples, the actual measured bending strength of the paper board 10 was remarkably enhanced by bonding the paperboard layer 3 to the liner paper layer 1. In particular, from the above results, it has been found that an increase in bending strength comparable to or exceeding the thickness of the board-like structure can be achieved by simply providing an additional paperboard layer 3 of about 1 mm. (Specifically, compare the bending strengths of Example 2-1 and Reference Example 3, and Example 3-1 and Reference Example 4). From this fact, the present inventor has found that the bending strength of the board can be efficiently increased by sticking the additional paperboard layer 3 without greatly increasing the thickness of the board.

  Furthermore, in Examples 1-1 to 1-3, when the basis weight of the paperboard layer 3 is increased, the magnification at which the actually measured bending strength of the board increases with respect to the reference example 1 is compared with the reference example 2. In Examples 2-1 to 2-3, increase in Examples 3-1 to 3-3 with respect to Reference Example 3 and in Examples 4-1 to 4-3 with respect to Reference Example 4, respectively. It was significantly higher than the magnification. This is because the basis weight of the liner paper layer 1 is made smaller than the basis weight of the liner paper layer 2, and when the paperboard layer 3 is reinforced, the effect of the reinforcement reinforces the bending strength of the whole board very efficiently. We have demonstrated that

In particular, comparing Example 1-3 and Example 2-3, in Example 2-3, the basis weight of the liner paper layer 1 increases from 210 g / m ² to 700 g / m ² , and the core paper Despite the fact that the basis weight is increased from 220 g / m ² to 280 g / m ² (the liner paper layer 2, the paperboard layer 3, and the core height are the same under the same conditions), the actual measured bending strength of the board is the example. It should be noted that 1-3 is superior. In Example 1-3, although the paper layer 1 and the core have a basis weight that is weaker than that of Example 2-3, the cost is significantly reduced compared to Example 2-3. The board as a whole had high bending strength. This is a result demonstrating the excellent and remarkable effect of the present invention.

In addition, when Example 1-3 and Example 4-1 are compared, in Example 1-3, lithographic paper having a basis weight of 2,800 g / m ² was used as the paperboard layer 3, whereas Example In 4-1, the paperboard layer 3 is not provided, but the basis weight of the core paper is increased from 220 g / m ² to 280 g / m ² , and the board thickness is increased from 30 mm to 50 mm. It should be noted that the cost increase due to the core condition change greatly exceeds the cost increase due to the use of a lithographic paper having a basis weight of 2,800 g / m ² as the paperboard layer 3. This is because a wide variety of inexpensive paper such as used waste paper can be used as the lithographic paper of the paperboard layer 3. Thus, when Example 1-3 and Example 4-1 were compared, Example 1-3 had higher bending strength, although Example 1-3 was cheaper. . This is also a result demonstrating the outstanding remarkable effect of the present invention.

  Below, the bending strength (Kg / m) of the board used in each Example is shown. In addition, since the weight of each board is a numerical value assumed to be 1 m wide, the bending strength actual measurement value is also converted to 1 m width accordingly. Specifically, since the size of each board is 500 mm wide × 333 mm long, the actual bending strength value of each board was multiplied by 3 in order to make it a bending strength in terms of 1 m width. Furthermore, in order to convert the numerical value measured by the one point concentrated load into the numerical value of the equally distributed load, it was doubled.

  As described above, in each of the examples, the bending strength per board weight is significantly larger than that of the reference example. This demonstrates the remarkable effect that the strength of the paper board structure of the present invention can be enhanced efficiently.

  Moreover, when the same test as the said Example was done about the example wooden board, the bending strength was 811.0 Kg. Comparing this value with the bending strength of 932.7 kg of Example 1-1, the strength of the paper board structure of the present invention is comparable to, or rather superior to, the wooden board. It becomes clear.

(Example 5)
From the results of Example 4, the present inventor has found that the application of the additional paperboard layer 3 can effectively increase the bending strength of the board without greatly increasing the thickness of the board. This example was examined in more detail.

In the following, the thickness and bending of the board-like structure when a web of 500 g / m ² (thickness: about 0.7 mm) is used as the liner paper layers 1 and 2 and the following 1 mm to 4 mm are used as the paperboard Indicates strength. Each board was allowed to stand for 24 hours under conditions of 23 ° C. and 50% humidity. Thereafter, the bending strength (Kg / m) of each structure was measured by converting the measured value at a single point concentrated load (load by force point 30 in FIG. 4) at a speed of 10 mm / min.
As can be seen from the results in Table 4, the bending strength was remarkably increased by sticking a board of 1 mm to 4 mm rather than increasing the thickness of the board-like structure (and hence the thickness of the entire board). From this, the present inventor has discovered that by combining a board of 1 mm to 4 mm with a board-like structure, a high bending strength of the board can be realized while suppressing an increase in the thickness of the board-like structure. The results in Table 4 showed that a significant increase in bending strength was achieved by adhering 1 mm to 4 mm paperboard to one side of a 15 mm to 40 mm board-like structure. For example, by bonding a 1 mm board having a thickness of about 3% to a board-like structure having a thickness of 30 mm, a bending strength exceeding that of a board-like structure having a thickness of 60 mm has been achieved.

(Example 6: Comparison between paperboard and cardboard)
For industrial paper, not only paperboard but also the option of using cardboard can be considered, so the final bending strength of the board can be increased depending on whether paperboard is used as the paper layer to be added to the board-like structure. Compared.

In the board structure of this example, 700 g / m ² (thickness: about 1 mm) roll paper was used as the liner paper layers 1 and 2. The thickness of the board-like structure was 30 mm. Each board was allowed to stand for 24 hours under conditions of a temperature of 23 ° C. and a humidity of 50%. Thereafter, the bending strength (Kg / m) of each structure was measured by converting the measured value at a single point concentrated load (load by force point 30 in FIG. 4) at a speed of 10 mm / min.
As is clear from the comparison between Table 5 and Table 6, the bending strength of 1,340.8 kg / m by bonding a 1 mm (basis weight 0.7 kg / m ² ) paperboard is 5 mm (basis weight 0.626 kg). / M ² ), the transverse bending strength of 107.8 kg / m and the longitudinal bending strength of 900.0 kg / m markedly exceeded. On the contrary, it was surprising that the bending strength when the corrugated cardboard having a thickness of 8 mm (basis weight 1.034 kg / m) was bonded was exceeded. When using paperboard, the bending strength can be increased without increasing the thickness as compared with the case where cardboard is used. Therefore, the bending strength per thickness and the bending strength per basis weight are remarkably large.

  It should be noted that when corrugated cardboard is used as the additional paper layer, there is a great difference in bending strength between the horizontal and vertical eyes. This difference in bending strength can be important when the board is used as a pallet top plate. In particular, in a pallet of a type in which lift claws can be inserted from both the X and Y directions, which is called “four-way insertion”, the bending strength of the weaker longitudinal eye must be used as a reference. In order to compensate for this, there is a cross-bonded two cardboard, but it is inevitable that the thickness is further increased. In this respect, the board to which the paperboard is bonded is advantageous because there is no difference in strength depending on the direction.

Furthermore, the effect of humidity was tested. The “23 ° C./50%” board was allowed to stand for 24 hours under conditions of a temperature of 23 ° C. and a humidity of 50%, and the “40 ° C./90%” board was allowed to stand under conditions of a temperature of 40 ° C. and a humidity of 90%. Thereafter, the bending strength (Kg / m) of each structure was measured by converting the measured value at a single point concentrated load (load by force point 30 in FIG. 4) at a speed of 10 mm / min.
As is clear from Tables 7 and 8 above, when corrugated cardboard is bonded as an additional paper layer, the bending strength is significantly reduced due to the influence of humidity. This can be particularly fatal in pallet applications that are used for long-time transportation under high temperature and high humidity conditions.

(Example 7)
When the liner paper layer is bonded to the core manufactured by cutting with the cutting blade shown in FIGS. 7A and 7B and an additional paperboard layer is pasted, and by cutting with the general cutting blade shown in FIGS. 7C and 7D The liner paper layer was bonded to the manufactured core and compared with the case where an additional paperboard layer was attached.

  Compared to the board made with the general cutting blade shown in FIGS. 7C and 7D, the board made with the preferred cutting blade shown in FIGS. 7A and 7B achieved a more stable and high bending strength. . That is, in a board manufactured using a general cutting blade, the bonded portion may not be able to withstand high bending strength, but in a board manufactured using a preferable cutting blade, there was no such thing. .

  The present invention is useful in providing a paper board structure that is inexpensive and has high bending strength. The paper board structure provided by the present invention can achieve strength comparable to that of a wood board at low cost, and is suitable for use as, for example, a pallet or a formwork. And since all the paper board structures of this invention are recyclable, it can contribute greatly to an environmental problem by reducing the usage-amount of wood resources.

1 Paper layer 1
2 Paper layer 2
3 Paper layer 3
4 Core 10 Paper board structure 21 Core material 22 Liner 23 Core unit

Claims (12)

A paper board comprising a board-like structure and a paperboard layer bonded to the board-like structure,
The board-like structure includes a core, and a first liner paper layer and a second liner paper layer bonded to the core so as to sandwich the core therebetween.
The paperboard layer is bonded to the first liner paper layer;
The board-like structure has a thickness of about 15 mm to about 40 mm,
The thicknesses of the first liner paper layer and the second liner paper layer are each independently about 0.5 mm to about 1.2 mm;
The thickness of the paperboard layer is from about 1 mm to about 4 mm;
Paper board.   The paper board according to claim 1, wherein the thickness of the board-like structure is about 15 mm or more and less than about 20 mm, and the bending strength of the paper board is about 450 kg / m or more.   The paper board according to claim 1, wherein the board-like structure has a thickness of about 20 mm or more and less than about 30 mm, and the bending strength of the paper board is about 650 kg / m or more.   The paper board according to claim 1, wherein the board-like structure has a thickness of about 30 mm or more and about 40 mm or less, and the bending strength of the paper board is about 950 kg / m or more.   The paper board according to any one of claims 1 to 4, wherein the thickness of the paperboard layer is about 1 mm to about 2 mm.   The paper board according to any one of claims 1 to 5, wherein the thickness of the paperboard layer is about 20% or less of the thickness of the board-like structure.   The paper board according to claim 6, wherein the thickness of the paperboard layer is about 15% or less of the thickness of the board-like structure.   The paper board according to claim 7, wherein the thickness of the paperboard layer is about 10% or less of the thickness of the board-like structure.   The paper board according to any one of claims 1 to 8, wherein the core has a shoulder portion on an adhesive surface with the first liner paper layer or the second liner paper layer.   A pallet including the paper board according to claim 1.   The formwork containing the paper board of any one of Claims 1-9. A method for producing a paper board having a predetermined bending strength,
The core is bonded to the first liner paper layer and the second liner paper layer so that the core is sandwiched between the first liner paper layer and the second liner paper layer, and is about 15 mm. Forming a board-like structure of about 40 mm;
Selecting a paperboard layer of about 1 mm to about 4 mm according to the predetermined bending strength;
Adhering the paperboard layer to the surface of the first liner paper layer, wherein the first liner paper layer and the second liner paper layer are each independently about 0.5 mm to about 1. The manufacturing method which is 2 mm.