Method for manufacturing pulp foam cushioning material, mold for pulp foam cushioning material, and pulp foam cushioning material

Abstract

To provide a method for manufacturing pulp foam cushioning material with less unevenness in dehydration areas than conventional methods, a mold for forming pulp foam cushioning material, and pulp foam cushioning material formed using the mold.SOLUTION: The method for manufacturing pulp foam cushioning material comprises: a step of mixing shredded pulp material 16, water, and a foaming agent to obtain a foamed body 19; filling a molding die (die body 20 and outer frame 90) with a quantity of foamed body 19 exceeding the volume of the pulp foam cushioning material 100, compressing the filled foamed body 19, and dehydrating and drying the foamed body 19. The molding mold comprises a mold body 20 made entirely of breathable material. Furthermore, during the drying step, the foam body 19 is dehydrated and dried while fully enclosed by the mold body 20.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This specification discloses a method for manufacturing a pulp foam buffer material used as a buffer material, a mold for molding the pulp foam buffer material, and the pulp foam buffer material.

Background Art

[0002] For example, in Patent Documents 1-6, buffer materials formed from pulp foam buffer materials are disclosed. For example, in the manufacturing process of a pulp foam buffer material, a pulp raw material obtained by finely chopping pulp, water, and a foaming agent are kneaded by a mixer or the like. The foam body obtained by kneading is filled into a mold. For example, a metal mold is used as the mold. By dehydrating the foam body filled in the mold, a porous pulp foam buffer material is obtained.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, if there is an unevenness in the dewatering state depending on the part of the foamy material, the distribution of porosity may become uneven. Therefore, this specification discloses a method for manufacturing pulp foam cushioning material that has less unevenness in dewatering locations than conventional methods, a mold for molding pulp foam cushioning material, and pulp foam cushioning material molded by said mold. [Means for solving the problem]

[0005] This specification discloses a method for manufacturing pulp foam cushioning material. This manufacturing method comprises the steps of: kneading pulp raw material obtained by shredding pulp material, water, and a foaming agent to obtain a foamy material; filling a mold with an amount of the foamy material greater than the volume of the pulp foam cushioning material; compressing the filled foamy material; and dehydrating and drying the foamy material. The mold comprises a mold body made entirely of a breathable material. In the drying step, the foamy material is dehydrated and dried while its entire surface is enclosed by the mold body.

[0006] According to the above configuration, the mold body is made entirely of a breathable material. Therefore, the foam can be dewatered from the entire surface. Furthermore, according to the above configuration, a larger volume of foam than the volume of the pulp foam buffer is filled into the mold and compressed. This allows the foam to come into contact with the entire inner surface of the breathable material mold body.

[0007] Furthermore, in the above configuration, a step of inserting a mesh panel between the mold and the foam may be included between the filling step and the compression step.

[0008] According to the above configuration, the mesh pattern of the mesh panel can be transferred to the surface of the pulp foam cushioning material. In other words, the surface of the pulp foam cushioning material can be used as a design surface.

[0009] This specification also discloses a mold for a pulp foam cushioning material. This mold is filled with a foamy material. The foamy material is obtained by kneading pulp raw material, which is obtained by shredding pulp material, water, and a foaming agent. The mold for the pulp foam cushioning material comprises a mold body. The mold body is made entirely of a breathable material.

[0010] According to the above configuration, the mold body is made entirely of a breathable material. Therefore, the foamy material can be dewatered from the entire surface.

[0011] Furthermore, in the above configuration, the mold body may be made of a flexible material. In this case, the mold for the pulp foam cushioning material includes an outer frame. The outer frame maintains the shape of the mold body from the outside.

[0012] According to the above configuration, since the mold body is made of a flexible material, when excessive pressure is applied to the foamed material, the flexible material deforms. This ensures the flexibility of the pulp foam cushioning material. In addition, the outer frame provides external support to maintain the shape of the mold body, which is prone to deformation.

[0013] Furthermore, in the above configuration, the mold body may be composed of multiple sub-parts.

[0014] According to the above configuration, release properties are improved compared to a single mold body.

[0015] Furthermore, in the above configuration, multiple sub-parts may include cross-shaped and columnar components. The cross-shaped component includes a cross-shaped wall. The cross-shaped wall divides the pulp foam cushioning material into four parts. A through-hole is provided in the center of the cross-shaped wall. The columnar component is inserted into the through-hole.

[0016] According to the above configuration, in the dewatering process of the foamy body, removing the columnar component through the through hole improves the air permeability of the mold body.

[0017] In the above configuration, the mold body may include an outer wall component, a first lid component, and a second lid component. The outer wall component surrounds the cross-shaped component. Also, the outer wall component is longer than the cross-shaped component. The first lid component is inserted into the filling space surrounded by the outer wall component and placed on the cross-shaped component. The second lid component is thicker than the first lid component and is laminated on the first lid component. After the filling space is filled with the foamed body, the foamed body is pushed downward by the second lid component and the first lid component. Further, after the foamed body is pushed in, the second lid component is removed.

[0018] According to the above configuration, when pushing in the foamed body, by using the thick lid component composed of the first lid component and the second lid component, the pressure related to the foamed body becomes uniform. Further, by removing the second lid component after pushing in, the air permeability of the upper part of the mold body is ensured.

[0019] In the above configuration, the first lid component may have higher water absorption than the cross-shaped component and the outer wall component.

[0020] According to the above configuration, compared with the cross-shaped component and the outer wall component, the first lid component has a higher holding force for the foamed body. Therefore, the first lid component suppresses the sagging of the foamed body against gravity. As a result, a surface along the shape of the first lid component can be molded.

[0021] In the above configuration, the molding die may be provided with a filling mechanism disposed above the mold body and the outer frame body. The filling mechanism includes a cylinder part and a piston. The cylinder part fills the foamed body from above the mold body. The piston is inserted into the cylinder part. The cylinder part is made of a non-water-permeable material. Further, the inner wall surface of the cylinder part is a smooth surface.

[0022] The foamed body protruding from the mold body may cause burrs after drying. According to the above configuration, since the inner wall surface of the cylinder part is composed of a non-water-permeable and smooth surface, the foamed body is less likely to remain in the cylinder part. As a result, the generation of burrs is suppressed.

[0023] In the above configuration, the molding die may be provided with a mesh panel sandwiched between the cross-shaped component and the first lid component.

[0024] According to the above configuration, the knitted shape of the mesh panel can be transferred to the surface of the pulp foam cushioning material. That is, a design surface can be formed on the surface of the pulp foam cushioning material.

[0025] In addition, in this specification, a pulp foam cushioning material is disclosed. This cushioning material is obtained by drying a foam body obtained by kneading a pulp raw material in which pulp material is shredded, water, and a foaming agent. The pulp foam cushioning material includes a core layer that is a foaming layer and a skin layer that covers the entire surface of the core layer. The skin layer has a higher fiber density than the core layer.

[0026] According to the above configuration, the entire surface of the core layer having flexibility and cushioning properties is covered with a skin layer having a relatively high fiber density. As a result, decomposition and peeling of the core layer are suppressed.

[0027] In addition, in the above configuration, the pulp foam cushioning material includes a bottom wall and a plurality of side walls. The plurality of side walls extend upward from the bottom wall and are spaced apart from each other. A central hole is formed by the bottom wall and the plurality of side walls. The bottom wall and the side walls include a core layer that is a foaming layer and a skin layer that covers the core layer. Further, the core layer of the side wall has higher cushioning properties than the core layer of the bottom wall.

[0028] According to the above configuration, the product accommodated in the central hole is held mainly by the side walls of the pulp foam cushioning material. Thereby, a product having a larger side area than the bottom area is reliably held by the pulp foam cushioning material.

[0029] In addition, in the above configuration, the core layer of the bottom wall may have a higher fiber density than the core layer of the side wall.

[0030] According to the above configuration, since the core layer of the bottom wall is less likely to be crushed, the product is less likely to sink into the bottom wall. As a result, the movement of the product held on the side wall in the height direction of the side wall is restricted.

[0031] In addition, in the above configuration, the side wall may be thicker than the bottom wall.

[0032] According to the above configuration, room for collapse of the side walls is ensured. [Effects of the Invention]

[0033] According to the method for manufacturing pulp foam cushioning material, the mold for molding pulp foam cushioning material, and the pulp foam cushioning material molded by said mold disclosed herein, the dewatering of the foamy material can be made less uneven than in conventional methods. [Brief explanation of the drawing]

[0034] [Figure 1] This diagram illustrates the process of generating a foamy state. [Figure 2] This is a perspective view illustrating a pulp foam cushioning material obtained using the mold according to this embodiment. [Figure 3] This is an exploded perspective view illustrating the various components of the mold according to this embodiment. [Figure 4] This diagram illustrates the assembly process (1 / 2) of the mold body. [Figure 5] This diagram illustrates the assembly process (2 / 2) of the mold body. [Figure 6] This diagram illustrates the pressurization process after filling the mold body with foam. [Figure 7] This is a diagram illustrating the drying process. [Figure 8] This is a partial cross-sectional perspective view illustrating the cross-sectional structure of the pulp foam cushioning material according to this embodiment. [Figure 9] This is a perspective view showing an example of how the pulp foam cushioning material according to this embodiment holds a product. [Figure 10] This is a partial cross-sectional structure illustrating the internal structure shown in Figure 9. [Figure 11] This is an exploded perspective view illustrating the various components of a mold according to another example of this embodiment. [Figure 12] This figure illustrates the assembly process (1 / 2) of the mold body of a mold according to another example of this embodiment. [Figure 13] This figure illustrates the assembly process (2 / 2) of the mold body of a mold according to another example of this embodiment. [Figure 14] This figure illustrates a pressurization process after filling the mold body with foam, according to another example of this embodiment. [Modes for carrying out the invention]

[0035] The following describes, with reference to the drawings, a method for manufacturing pulp foam cushioning material according to this embodiment, a mold for molding pulp foam cushioning material, and pulp foam cushioning material molded by said mold. The shapes, materials, quantities, and numerical values ​​described below are illustrative examples for illustrative purposes and can be appropriately changed according to the specifications of the mold and pulp foam cushioning material. In addition, the same reference numerals are used for equivalent elements in all drawings below. <Overall structure of the mold>

[0036] A foamy substance 19, as illustrated in Figure 1, is filled into a mold body 20, as illustrated in Figure 5. Then, as illustrated in Figure 6, the filled foamy substance 19 is pressurized by the first lid part 70 and the second lid part 80. Furthermore, as illustrated in Figure 7, the mold body 20, housed in the outer frame 90, is placed in a dryer 110. By dewatering the foamy substance 19 in the dryer 110, a pulp foam cushioning material 100, as illustrated in Figure 2, is obtained. <Foam formation process>

[0037] Referring to Figure 1, the raw materials for the foamy substance 19 consist of water 15, pulp raw material 16, and a foaming agent 17. The pulp raw material 16 can be obtained, for example, by shredding pulp material such as corrugated cardboard.

[0038] The foaming agent 17 is, for example, a surfactant. To reduce environmental and human health burdens, the foaming agent 17 may be composed of household products. For example, the foaming agent 17 may be composed of laundry detergent, body soap, or shampoo.

[0039] First, water 15 and pulp material 16 are placed into the mixer 10. For example, roughly equal volumes of water 15 and pulp material 16 are put into the mixer 10. Then, the lid 11 of the mixer 10 is closed and the mixer 10 is driven. As a result, the pulp material 16 is further crushed and mixed with the water 15. This yields a slurry 18.

[0040] Next, a foaming agent 17 is added to the slurry 18. The amount of foaming agent 17 may be, for example, about 1 / 10 of the amount of water 15. After the foaming agent 17 is added, the lid 11 is closed and the mixer 10 is driven again. The slurry 18 and the foaming agent 17 are mixed together to obtain a foamy substance 19. The foamy substance 19 is filled into a mold. The mold comprises the mold body 20 and outer frame 90 shown in Figure 3. <Structure of the mold>

[0041] Figure 3 illustrates an exploded perspective view of a mold according to this embodiment. The mold comprises a mold body 20 and an outer frame 90. The mold body 20 is made entirely of a breathable material. Furthermore, for example, the mold body 20 is made of a flexible member. For example, the mold body 20 is made of sponge. That is, the mold body 20 is made of a porous member in which spongy fibers form a mesh structure.

[0042] The mold body 20 is composed of multiple sub-parts. For example, the mold body 20 includes a base 30, a cross-shaped part 40, a columnar part 50, outer wall parts 60A, 60B, 60C, 60D, a first cover part 70, and a second cover part 80.

[0043] The base 30 is a rectangular flat plate component. As illustrated in Figure 4, a cross-shaped component 40 is placed on the base 30. The cross-shaped component 40 comprises a rectangular tube 42 and partition walls 41A, 41B, 41C, and 41D.

[0044] The rectangular tube 42 is located in the center of the cross-shaped component 40. A through hole 43 is drilled in the rectangular tube 42. As illustrated in Figure 4, when filling with the foamy body 19, a columnar component 50 is inserted into the rectangular tube 42. In other words, the through hole 43 is blocked by the columnar component 50.

[0045] Partition walls 41A, 41B, 41C, and 41D extend from the rectangular tube 42 in the front, back, left, and right directions. In other words, the partition walls 41A, 41B, 41C, and 41D form a cross-shaped wall. A through-hole 43 is also formed in the center of the cross-shaped wall.

[0046] Partition walls 41A and 41C are positioned opposite each other with the rectangular tube 42 in between. Partition walls 41B and 41D are also positioned opposite each other with the rectangular tube 42 in between. The distance W2 from the end of partition wall 41A (the end furthest from the rectangular tube 42) to the end of partition wall 41C is equal to the width W1 of the base 30. Also, the distance L2 from the end of partition wall 41B to the end of partition wall 41D is equal to the depth L1 of the base 30.

[0047] The partition walls 41A, 41B, 41C, and 41D correspond to the slits 102A, 102B, 102C, and 102D of the pulp foam cushioning material 100. In other words, the partition walls 41A, 41B, 41C, and 41D divide the pulp foam cushioning material 100 into four parts (side walls 101A, 101B, 101C, and 101D).

[0048] To improve release properties, the upper ends (the ends furthest from the base 30) of the partition walls 41A, 41B, 41C, and 41D are rounded. In other words, the upper ends of the partition walls 41A, 41B, 41C, and 41D have a rounded shape.

[0049] Exterior wall components 60A, 60B, 60C, and 60D are L-shaped components when viewed from above. Exterior wall components 60A, 60B, 60C, and 60D are longer than the cross-shaped component 40. In other words, the height of exterior wall components 60A, 60B, 60C, and 60D is greater than that of the cross-shaped component 40. For example, the height of exterior wall components 60A, 60B, 60C, and 60D is twice the height of the cross-shaped component 40.

[0050] The exterior wall components 60A, 60B, 60C, and 60D are each equipped with L-shaped walls 61A, 61B, 61C, and 61D. Recesses 62A, 62B, 62C, and 62D are formed in the lower portions of both ends (wing ends) of the L-shaped walls 61A, 61B, 61C, and 61D. As illustrated in Figures 3 and 5, the recesses 62A and 62B fit into the ends of the partition wall 41A. Similarly, the recesses 62B and 62C fit into the ends of the partition wall 41B. The recesses 62C and 62D fit into the ends of the partition wall 41C. Furthermore, the recesses 62A and 62D fit into the ends of the partition wall 41D.

[0051] Referring to Figure 5, a guideline 64 may be provided on the inner surface of the outer wall component 60D. The guideline 64 is a reference line indicating how far the lid 91 should be pushed in. The distance from the guideline 64 to the top surface of the cross-shaped component 40 is greater than the sum of the thicknesses of the first lid component 70, the second lid component 80, and the lid 91. In other words, as shown by the spacing D1 illustrated in Figure 6, when the lid 91 is pushed in up to the guideline 64, the bottom surface of the first lid component 70 and the top surface of the cross-shaped component 40 are separated. The foamy material 19 is filled into this separated space. The foamy material 19 filled into this space becomes the bottom wall 104 of the pulp foam cushioning material 100.

[0052] The first lid part 70 and the second lid part 80 are inserted into the filling space surrounded by the outer wall parts 60A, 60B, 60C, and 60D. In other words, after the foamy substance 19 is filled into the mold body 20 in the state shown in Figure 5 (open state), the first lid part 70 and the second lid part 80 are placed over the foamy substance 19. The first lid part 70 becomes the lower layer and the second lid part 80 becomes the upper layer, so they are stacked on top of each other. The first lid part 70 and the second lid part 80 have the same shape as the opening formed by the outer wall parts 60A, 60B, 60C, and 60D. The second lid part 80 is formed to be thicker than the first lid part 70.

[0053] Furthermore, the first lid component 70 has higher water absorption than the base 30, the cross-shaped component 40, the columnar component 50, and the outer wall components 60A, 60B, 60C, and 60D. The first lid component 70 holds the foamy material 19 from above. Because the water absorption of the first lid component 70 is higher than that of the other components of the mold body 20, the first lid component 70 can hold the foamy material 19 against gravity. As the first lid component 70 holds the foamy material 19 from above, the surface of the finished pulp foam cushioning material 100 (more specifically, the surface of the bottom wall 104) becomes planar, similar to the first lid component 70.

[0054] For example, the first lid component 70 is made of cellulose sponge. Also, the base 30, the cross-shaped component 40, the columnar component 50, and the outer wall components 60A, 60B, 60C, and 60D are made of urethane foam sponge.

[0055] Referring to Figure 3, the outer frame 90 is a mesh-like component throughout. The outer frame 90 is more rigid than the mold body 20. For example, the outer frame 90 is made of plastic or metal. The outer frame 90 maintains the shape of the mold body 20 from the outside.

[0056] The outer frame 90 comprises a box-shaped mesh 95 and a lid 91. The box-shaped mesh 95 has a bottom wall 97 and four side walls 96. The top of the box-shaped mesh 95 is open. The mold body 20 is assembled inside the box-shaped mesh 95 as shown in Figures 4, 5, and 6, and the foamy material 19 is filled inside. The dimensions of the bottom wall 97 are the same as the dimensions of the base 30 (W1 × L1). The depth of the box-shaped mesh 95 is the thickness of the base 30 plus the height of the outer wall component 60, plus a predetermined margin.

[0057] The lid 91 is a mesh-like flat plate component. In other words, the lid 91 is a mesh panel. Its top view shape is identical to that of the first lid component 70 and the second lid component 80. <Manufacturing process for pulp foam cushioning material>

[0058] The base 30, the cross-shaped component 40, and the columnar component 50 are assembled inside the box-shaped mesh 95 in the state shown in Figure 4. Furthermore, the cross-shaped component 40 is covered by the outer wall components 60A, 60B, 60C, and 60D as shown in Figure 5. The foamy material 19 is filled into the open mold body 20 as shown in Figure 5. Here, considering the volume reduction due to compression and dewatering / drying, the amount of foamy material 19 to be filled [cm] 3 ] is greater than the volume of 100 units of pulp foam cushioning material.

[0059] The first lid component 70 is placed over the filled foamy body 19. Then, the second lid component 80 is stacked on top of the first lid component 70. Finally, the lid 91 of the outer frame 90 is placed over the first lid component 70.

[0060] The lid 91 is pressurized by an operator or a press machine. The foamy substance 19 is pushed downward by the first lid part 70 and the second lid part 80 until the lid 91 reaches the guideline 64. The foamy substance 19 is pressed by the first lid part 70 and the second lid part 80, which is thicker, so that the foamy substance 19 spreads to every corner of the mold body 20.

[0061] Furthermore, because the mold body 20 is made of a flexible material, excessive compression of the foamed material 19 is suppressed. In other words, if excessive pressure is applied to the foamed material 19, the mold body 20 deforms. This ensures the flexibility of the molded product, the pulp foamed cushioning material 100.

[0062] Furthermore, the outside of the mold body 20 is held in place by the outer frame 90. Therefore, the bulging of the mold body 20 is suppressed by the outer frame 90.

[0063] Furthermore, as the foamy material 19 is compressed, the fiber density increases at the interface between the foamy material 19 and the mold body 20. In other words, the fiber density on the surface of the mold body 20 (the contact surface with the foamy material 19) becomes higher than the fiber density inside the foamy material 19.

[0064] The fibers pushed onto the surface of the mold body 20 become entangled in the porous surface of the mold body 20. This entangled state continues even during the dehydration and drying process, forming the skin layer 106.

[0065] When the lid 91 of the outer frame 90 is pushed up to the guideline 64, the lid 91 is removed, and then the second lid part 80 is removed. Then, the lid 91 is placed on top of the first lid part 70. By removing the thick second lid part 80 before drying, ventilation during drying is ensured, especially for the upper part of the foamy body 19.

[0066] The outer frame 90, the mold body 20, and the filled foamy material 19 are housed in a dryer 110 (see Figure 7). For example, in the dryer 110, the chamber is under negative pressure. Inside the dryer 110, the foamy material 19 is dewatered by suction. Since the mold body 20 and the outer frame 90 are made of a breathable material throughout, uniform dewatering is achieved. In other words, during dewatering and drying, by surrounding the entire surface of the foamy material 19 with the breathable mold body 20 and outer frame 90, uniform dewatering and drying of the foamy material 19 is achieved.

[0067] Here, the drying process may be divided into two stages. For example, the drying process may be divided into a first and second half, and in between the first and second halves, the mold (mold body 20 and outer frame 90) may be removed from the dryer 110. Furthermore, the mold body 20 is removed from the box-shaped mesh 95. In addition, the base 30 is temporarily removed, and the columnar part 50 is pulled out from the cross-shaped part 40. Then the base 30 is returned, and the mold body 20 is placed back into the box-shaped mesh 95. Then the lid 91 is placed over it, and the mold and the semi-dried foamy body 19 are placed back into the dryer 110. After that, the second half of the drying process begins. The center of the cross-shaped part 40 becomes hollow, which improves ventilation.

[0068] Once the latter half of the drying process is complete, the mold (mold body 20 and outer frame 90) is removed from the dryer 110. Then the mold body 20 is removed from the outer frame 90. At this point, the pulp foam cushioning material 100 is molded inside the mold body 20 in an inverted state compared to Figure 2.

[0069] The mold body 20 is peeled away from the pulp foam cushioning material 100. High release properties are achieved because the mold body 20 is composed of multiple sub-parts. Furthermore, the mold body 20 is made of a flexible porous material such as sponge. Therefore, the mold body 20 is peeled away from the pulp foam cushioning material 100 while deforming.

[0070] For example, the first lid component 70, outer wall components 60A, 60B, 60C, 60D, base 30, and cross-shaped component 40 are sequentially peeled off from the pulp foam cushioning material 100. This yields the pulp foam cushioning material 100 illustrated in Figure 2. <Pulp foam cushioning material>

[0071] Figure 2 illustrates a pulp foam cushioning material 100 obtained using the mold according to this embodiment. Figure 8 illustrates a partial cross-sectional perspective view of the pulp foam cushioning material 100. The pulp foam cushioning material 100 has the shape transferred from the mold. The pulp foam cushioning material 100 includes a bottom wall 104 and side walls 101A, 101B, 101C, and 101D.

[0072] The bottom wall 104 is a rectangular plate-like component when viewed from below. The side walls 101A, 101B, 101C, and 101D extend upward and linearly from the bottom wall 104. For example, each of the side walls 101A, 101B, 101C, and 101D is L-shaped when viewed from above.

[0073] The side walls 101A, 101B, 101C, and 101D are separated from each other by the slits 102A, 102B, 102C, and 102D. A central hole 103 is formed in the center of the pulp foam cushioning material 100, surrounded by the side walls 101A, 101B, 101C, and 101D. The central hole 103 extends from the upper surfaces of the side walls 101A, 101B, 101C, and 101D to the upper surface of the bottom wall 104.

[0074] The pulp foam cushioning material 100 is a cushioning material in which the product is placed within the central hole 103. In other words, the central hole 103 becomes the space for storing the product. When storing the product, it is inserted into the central hole 103 by pushing aside the side walls 101A, 101B, 101C, and 101D.

[0075] Referring to Figure 8, the cross-sectional structure of the pulp foam cushioning material 100 comprises a skin layer 106 and core layers 105A, 105B, and 105C. The skin layer 106 is a thin film layer with a higher fiber density compared to the core layers 105A, 105B, and 105C. The entire surface of the pulp foam cushioning material 100 is covered with the skin layer 106.

[0076] As described above, during the molding of the pulp foam cushioning material 100, the foam body 19 is drawn into the outer edge of the foam body 19 that is in contact with the mold body 20 during the suction dewatering process. Then the moisture from the foam body 19 is drawn out from the mold body 20. In other words, the fiber density becomes higher at the outer edge of the foam body 19 that is in contact with the mold body 20. As a result, a skin layer 106 is formed on the surface of the pulp foam cushioning material 100.

[0077] As will be described later, the core layers 105A, 105B, and 105C have a low fiber density and are prone to peeling off in the form of small fragments. By covering the entire surface of the core layers 105A, 105B, and 105C with the skin layer 106, peeling is suppressed.

[0078] The core layers 105A, 105B, and 105C are foamed layers and provide cushioning properties. Referring to Figure 8, the pulp foamed cushioning material 100 comprises core layers 105A, 105B, and 105C with different fiber densities (in other words, foaming ratios).

[0079] The core layer 105A is the internal structure of the side walls 101A, 101B, 101C, and 101D. The core layer 105A has the lowest fiber density (highest foaming ratio) among the core layers 105A, 105B, and 105C. In other words, the core layer 105A has the highest cushioning properties among the core layers 105A, 105B, and 105C. Also, the thickness T1 of the side walls 101A, 101B, 101C, and 101D is thicker than the thickness T2 of the bottom wall 104. In other words, the side walls 101A, 101B, 101C, and 101D are equipped with a core layer 105A that has high cushioning properties and sufficient thickness.

[0080] The core layer 105C is the internal structure of the bottom wall 104. Of the core layers 105A, 105B, and 105C, the core layer 105C has the highest fiber density (lowest foaming ratio). In other words, the core layer 105C has the lowest cushioning properties among the core layers 105A, 105B, and 105C. To put it another way, the core layer 105C is the least likely to collapse among the core layers 105A, 105B, and 105C.

[0081] The core layer 105B is formed at the connection point between the bottom wall 104 and the side walls 101A, 101B, 101C, and 101D. The fiber density of the core layer 105B is between the fiber density of the core layer 105A and the fiber density of the core layer 105C.

[0082] As shown in Figure 6 above, during the molding process of the pulp foam cushioning material 100, the foamy body 19 corresponding to the bottom wall 104 is pressurized against the first lid component 70, the second lid component 80, and the lid body 91. As a result, the voids in the bottom wall 104 are compressed, and the fiber density is reduced.

[0083] The above pressurization is performed to ensure that the foamy material 19 reaches every corner of the mold body 20. In addition, the above pressurization is performed to make the shape of the lower surface of the bottom wall 104 of the pulp foam cushioning material 100 conform to the shape of the bottom surface of the outer box 120 (see Figure 9). For example, the lower surface (the surface that contacts the foamy material 19) of the first lid component 70 is formed to conform to the shape of the bottom surface of the outer box 120.

[0084] Figures 9 and 10 illustrate the packaging configuration of the container 125 using the pulp foam cushioning material 100 according to this embodiment. The pulp foam cushioning material 100 holds the container 125 inside. For example, the height of the container 125 is less than the height of the side walls 101A, 101B, 101C, and 101D.

[0085] With the container 125 held in place, the pulp foam cushioning material 100 is inserted into the outer box 120. During this insertion process, the inner walls of the side walls 101A, 101B, 101C, and 101D are indented and deformed by the container 125. As described above, since the side walls 101A, 101B, 101C, and 101D are thicker than the bottom wall 104, there is room for the core layer 105A to be compressed.

[0086] Due to the concave deformation of the side walls 101A, 101B, 101C, and 101D, the side walls 101A, 101B, 101C, and 101D take on a hook shape, as illustrated in Figure 10. The hook shape of the side walls 101A, 101B, 101C, and 101D prevents the container 125 from falling out of the pulp foam cushioning material 100.

[0087] Thus, in the pulp foam cushioning material 100 according to this embodiment, the container 125 is held in place by the deformation of the side walls 101A, 101B, 101C, and 101D, which have higher cushioning properties than the bottom wall 104. In particular, for containers 125 where the side surface area is larger than the bottom surface area, a high holding effect can be obtained from the side walls 101A, 101B, 101C, and 101D.

[0088] Furthermore, the cushioning properties of the bottom wall 104 are lower than those of the side walls 101A, 101B, 101C, and 101D, meaning that the bottom wall 104 is less likely to collapse compared to the side walls 101A, 101B, 101C, and 101D, thus restricting the vertical movement of the container 125. In other words, because the container 125 is less likely to sink into the bottom wall 104 of the pulp foam cushioning material 100, the movement of the container 125 along the height direction of the side walls 101A, 101B, 101C, and 101D is restricted. <Another example of a mold>

[0089] Figure 11 illustrates an exploded perspective view of a mold according to another embodiment of this model. The mold comprises a mold body 20, an outer frame 90, and a filling mechanism 93. The mold body 20 is made entirely of a breathable material. Alternatively, the mold body 20 may be made of a flexible material. For example, the mold body 20 may be made of a sponge. That is, the mold body 20 is made of a porous material in which spongy fibers form a mesh structure.

[0090] In contrast to the mold body 20 in Figure 3, the mold body 20 in Figure 11 is provided with a piston 92 (described later) instead of the second lid part 80. Furthermore, the mold body 20 in Figure 11 is equipped with outer wall parts 160A-160D. The outer wall parts 160A-160B are shorter in shape than the outer wall parts 60A-60D in Figure 3. For example, the portion of the outer wall parts 160A-160B above the recesses 162A-162D is set to the same height as the thickness of the bottom wall 104 of the pulp foam cushioning material 100.

[0091] The outer frame 90 also includes a lid 191 and a box-shaped mesh 195. Unlike the outer frame 90 in Figure 3, the lid 191 is smaller. For example, the lid 191 has the same shape as the opening 94A of the cylindrical portion 94. Furthermore, to ensure release from the pulp foam cushioning material 100, the lid 191 is made of a flexible material.

[0092] In addition, unlike the outer frame 90 in Figure 3, the box-shaped mesh 195 is made of a metal material such as aluminum. The box-shaped mesh 195 has side walls 196 and a bottom wall 197, and is open at the top. The side walls 196 and bottom wall 197 are made of perforated metal.

[0093] The filling mechanism 93 comprises a piston 92 and a cylindrical portion 94. The piston 92 and cylindrical portion 94 are made of a non-permeable material. For example, the piston 92 and cylindrical portion 94 are made of a metal material such as aluminum.

[0094] The cylindrical portion 94 may be rectangular in shape. The opening 94A of the cylindrical portion 94 may be the same shape and size as the opening 161 (see Figure 12) formed by the outer wall components 160A-160D. The same size means that the vertical and horizontal dimensions of the openings 94A and 161 are the same.

[0095] The inner wall surface 94D of the cylindrical portion 94 (see Figure 13) is a smooth surface. For example, the inner wall surface 94D is polished to a mirror finish. As described above, the cylindrical portion 94 is impermeable to water. Therefore, the inner wall surface 94D is both impermeable to water and smooth.

[0096] As described later, foamy material 19 is injected into the cylindrical portion 94. Since the inner wall surface 94D of the cylindrical portion 94 is impermeable and smooth, the residue of foamy material 19 on the inner wall surface 94D is suppressed. After the foamy material 19 dries, any portion that deviates from the mold body 20 (see Figure 13) becomes burr. By suppressing the residue of foamy material 19 on the inner wall surface 94D, the generation of burrs is suppressed.

[0097] The piston 92 comprises a main body 92A and a handle 92B. The main body 92A is inserted into the opening 94A of the cylindrical portion 94. The shape of the main body 92A may be the same as the shape of the opening 94A. The piston 92 and the cylindrical portion 94 are formed such that the clearance between the opening 94A and the main body 92A is less than or equal to a predetermined value (for example, 1 mm).

[0098] For example, the piston 92 has a solid structure with no hollow parts. For example, the piston 92 weighs between 3 kg and 15 kg. When compressing and filling the foamy substance 19 into the mold body 20, the foamy substance 19 is filled into the mold body 20 by the weight of the piston 92.

[0099] The handle 92B protrudes from the main body 92A. The handle 92B is held by the operator when inserting the piston 92 into the cylindrical part 94. The handle 92B also serves as a stopper when inserting the piston 92 into the cylindrical part 94.

[0100] Referring to Figure 12, with the cross-shaped component 40, the outer wall components 160A-160D, and the base 30 assembled, the mold body 20 is housed in the box-shaped mesh 195. As illustrated in Figure 13, the side walls 196 of the box-shaped mesh 195 protrude upward from the upper end of the mold body 20. The bottom wall 104 of the pulp foam cushioning material 100 is formed between the upper end of the mold body 20 and the upper end of the side wall 196.

[0101] Furthermore, a filling mechanism 93 (see Figure 11) is positioned above the box-shaped mesh 195 of the mold body 20 and the outer frame 90. That is, referring to Figure 13, a cylindrical portion 94 is placed on top of the box-shaped mesh 195. During this placement, the cylindrical portion 94 is aligned with the box-shaped mesh 195 by the lower guide 94B.

[0102] Furthermore, referring to Figure 14, a foamy substance 19 (not shown) is filled into the cylindrical portion 94. As described above, the amount of foamy substance 19 filled exceeds the volume of the pulp foam cushioning material 100. For example, the foamy substance 19 is filled up to the inside of the cylindrical portion 94.

[0103] Furthermore, the lid 191 and the first lid component 70 are placed on the opening 94A of the cylindrical portion 94. As described above, 191 is a mesh panel. The lid 191 is sandwiched between the cross-shaped part 40 (see Figure 12) of the mold body 20 and the first lid part 70. The lid 191 also comes into contact with the foamed material 19. As a result of drying and dewatering the foamed material 19, the mesh pattern of the lid 191 is transferred to the surface of the pulp foamed cushioning material 100 that comes into contact with the lid 191. In other words, by using the lid 191, a design can be created on the surface of the pulp foamed cushioning material 100.

[0104] Referring to Figure 14, the lid 191 and the first lid part 70 are housed within the cylindrical portion 94. Furthermore, the piston 92 is inserted into the cylindrical portion 94. For example, the main body 92A enters the opening 94A while being guided by the upper guide 94C of the cylindrical portion 94. As the piston 92 enters (sinks) into the cylindrical portion 94 by its own weight, the foamy substance 19 is compressed and filled into the mold body 20.

[0105] During the compression filling process, the fiber density at the interface between the foam body 19 and the mold body 20 is higher than that inside the foam body 19. This high-density state is maintained as the fibers become entangled in the mold body 20, which is made of a breathable porous material. As the foam body 19 is dried and dewatered in this state, a skin layer 106 is formed on the surface of the pulp foam cushioning material 100. [Explanation of Symbols]

[0106] 10 Mixer, 15 Water, 16 Pulp raw material, 17 Foaming agent, 18 Slurry, 19 Foamed material, 20 Main body, 30 Base, 40 Cross-shaped part, 43 Through hole, 50 Columnar part, 60A-60D Outer wall part, 70 First lid part, 80 Second lid part, 90 Outer frame, 91 Lid, 95 Box-shaped mesh, 100 Pulp foam cushioning material, 101A-101D Side walls, 102A-102D Slits, 103 Central hole, 104 Bottom wall, 105A-105C Core layer, 106 Skin layer

Claims

1. A method for manufacturing pulp foam cushioning material, The process involves mixing pulp raw material (which is obtained by shredding pulp material), water, and a foaming agent to obtain a foamy substance, A step of filling a mold with a volume of foamy material greater than the volume of pulp foam cushioning material, The steps include compressing the foamy material after filling, The steps include dehydrating and drying the foamy material, Equipped with, The mold is made entirely of a breathable material and includes a flexible mold body that can be deformed by the pressure from the foam during the step of compressing the foam. In the dehydration and drying step, the foamy body is dehydrated and dried while the entire surface of the foamy body is surrounded by the mold body. A method for manufacturing pulp foam cushioning material.

2. A method for producing a pulp foam cushioning material according to claim 1, Between the filling step and the compression step, there is a step of inserting a mesh panel between the mold and the foamy body. A method for manufacturing pulp foam cushioning material.

3. A mold for pulp foam cushioning material, in which a foamy substance obtained by kneading pulp raw material (which is made from shredded pulp material), water, and a foaming agent is filled; A mold for pulp foam cushioning material, comprising a mold body made entirely of breathable material and capable of deforming when pressure is applied from the foamed body.

4. A mold for molding pulp foam cushioning material according to claim 3, The aforementioned body is equipped with an outer frame that maintains the shape of the main body from the outside, A mold for molding pulp foam cushioning material.

5. A mold for molding pulp foam cushioning material according to claim 3, The aforementioned main body is composed of multiple sub-parts, A mold for molding pulp foam cushioning material.

6. A mold for molding pulp foam cushioning material according to claim 5, Multiple of the aforementioned sub-parts are A cross-shaped component comprising a cross-shaped wall that divides the pulp foam cushioning material into four parts, and further having a through hole in the center of the cross-shaped wall, A columnar component is inserted into the aforementioned through hole, A mold for molding pulp foam cushioning material, equipped with [a specific feature].

7. A mold for molding pulp foam cushioning material according to claim 6, The aforementioned main body is, Surrounding the aforementioned cross-shaped component is an outer wall component that is longer than the aforementioned cross-shaped component, A first lid component is inserted into the filling space surrounded by the outer wall component and positioned on the cross-shaped component, The device comprises a second lid component which is thicker than the first lid component and is laminated on the first lid component, After the foamy substance is filled into the filling space, the foamy substance is pushed downward by the second lid component and the first lid component. After the foamy body is pressed in, the second lid component is removed. A mold for molding pulp foam cushioning material.

8. A mold for molding pulp foam cushioning material according to claim 7, The first lid component has higher water absorption than the cross-shaped component and the outer wall component. A mold for molding pulp foam cushioning material.

9. A mold for molding pulp foam cushioning material according to claim 4, The mold body and the outer frame are equipped with a filling mechanism located above them, The aforementioned filling mechanism is A cylindrical portion for filling the foamy substance from above the mold body, A piston inserted into the cylindrical portion, Equipped with, The cylindrical portion is made of a non-permeable material. The inner wall surface of the cylindrical portion is a smooth surface. A mold for molding pulp foam cushioning material.

10. A mold for a pulp foam cushioning material according to claim 7, The mesh panel is sandwiched between the cross-shaped component and the first lid component. A mold for molding pulp foam cushioning material.

11. A pulp foam buffer material is made by kneading pulp raw material (which is made from shredded pulp material), water, and a foaming agent, and then drying the resulting foamy material. The core layer is a foamed layer, A skin layer covering the entire surface of the core layer, Equipped with, The skin layer has a higher fiber density than the core layer. The bottom wall and, Multiple side walls extending upward from the bottom wall and spaced apart from each other, Equipped with, The bottom wall and the side wall comprise the core layer and the skin layer covering the core layer. The core layer of the side wall has a lower fiber density compared to the core layer of the bottom wall. Pulp foam cushioning material.

12. A pulp foam cushioning material according to claim 11, The bottom wall and the plurality of side walls form a central hole. Pulp foam cushioning material.

13. A pulp foam cushioning material according to claim 12, The side wall is thicker than the bottom wall. Pulp foam cushioning material.

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