Buffer material and manufacturing method of buffer material

Abstract

To provide an environmentally friendly, lightweight buffer material 8 with excellent moisture resistance.SOLUTION: A buffer material 8 is formed by heating and compressing a mixture consisting of kapok fibers as hollow fibers 1, and a shellac resin serving as a bonding material 2 that bonds the kapok fibers together.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cushioning material and a method for manufacturing the cushioning material. [Background technology]

[0002] For example, Patent Document 1 discloses a cushioning material formed by adding a binder to fibers derived from pulp such as waste paper. The cushioning material reduces the environmental load, can be suitably recycled, and has excellent buckling resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-82786 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is room for improvement in the cushioning material of Patent Document 1. Specifically, conventional pulp-derived cushioning materials have the problems of being heavy due to their high density and lacking moisture resistance. In other words, there has been a demand for an environmentally friendly, lightweight cushioning material with excellent moisture resistance, and a method for manufacturing the same. [Means for solving the problem]

[0005] A buffer material according to one aspect of the present application is formed by heating and compressing a mixture of hollow fibers and a binder that binds the hollow fibers together.

[0006] A method for manufacturing a buffer material according to one embodiment of the present application includes the steps of: defibrating a material containing hollow fibers to obtain the hollow fibers; mixing the hollow fibers with a binder to obtain a mixture; stacking multiple layers of the mixture to obtain a laminate; and heating and pressurizing the laminate to form a buffer material. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view showing an overview of a cushioning material according to a first embodiment. [Figure 2] FIG. 10 is a flowchart showing the flow of a method for manufacturing a cushioning material. [Figure 3] 1A to 1C are diagrams illustrating one aspect of a manufacturing process. [Figure 4] 1A to 1C are diagrams illustrating one aspect of a manufacturing process. [Figure 5] 1A to 1C are diagrams illustrating one aspect of a manufacturing process. [Figure 6] Schematic diagram of a compressive stress measurement device. [Figure 7] FIG. 2 is a graph showing compressive stress-strain characteristics. [Figure 8] FIG. 10 is a graph showing the damping coefficient distortion characteristics. [Figure 9] FIG. 10 is a perspective view showing an outline of a cushioning material according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiment 1 ***Overview of cushioning materials*** 1 is a perspective view showing an outline of a cushioning material of embodiment 1. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] 1 is a cushioning material that protects products from impact when packaging electrical products, etc. Note that the cushioning material is not limited to protecting products, and may be used for any purpose where cushioning is useful, such as a helmet cushioning material. 1, the cushioning material 8 has a rectangular shape with a length L of about 8 cm, a width W of about 5 cm, and a thickness T of about 3 cm. However, the dimensions are not limited to these, and any dimensions suitable for the intended use may be used.

[0010] The buffer material 8 is formed by heating and compressing a mixture of hollow fibers 1 and a binder 2 that binds the hollow fibers 1. In a preferred example, kapok fibers are used as the hollow fibers 1, and shellac resin is used as the binder 2. In other words, the hollow fibers 1 are kapok fibers, and the binder 2 is shellac resin. The method for manufacturing the buffer material 8 will be described later. The cushioning material 8 is formed by stacking multiple fiber layers 5 in the length direction L. In a preferred example, the direction in which the cushioning material 8 receives weight is the thickness direction T. However, this is not limited to this, and any direction intersecting the stacking direction of the fiber layers 5 may be used, and the cushioning material 8 may receive weight in the width direction W. In other words, the kapok fibers are aligned in the direction in which the cushioning material 8 receives weight. The uncolored cushioning material 8 is light brown and has a marbled appearance.

[0011] ***How ​​cushioning materials are manufactured*** Fig. 2 is a flow chart showing the flow of the method for manufacturing the cushioning material, and Figs. 3 to 5 are diagrams showing one embodiment of the manufacturing process. Here, the method for manufacturing the cushioning material 8 will be described mainly with reference to FIG. 2, and also with reference to FIGS. 3 to 5 as appropriate.

[0012] In step S10, a material containing hollow fibers 1 is defibrated. In a preferred embodiment, the material is naturally occurring kapok cotton. The kapok fibers contained in kapok cotton have an extremely high hollowness of 70% to 80%, making it lightweight at approximately 1 / 8 the weight of cotton. In a preferred embodiment, the kapok cotton is fed into a known defibrator and defibrated so that the fiber length of the kapok fibers is 0.1 mm or more and 10.0 mm or less. In other words, the fiber length of the kapok fibers as hollow fibers 1 is 0.1 mm or more and 10.0 mm or less.

[0013] In step S11, hollow fibers 1 and binder 2 are mixed to produce a mixture. In a preferred embodiment, binder 2 is a naturally occurring shellac resin. The shellac resin used is a powder with a particle size ranging from 1 μm to 100 μm. The particle size is more preferably 10 μm to 20 μm. In this step, kapok fibers and shellac resin are weighed and mixed together, and the mixture is air-agitated in a container. The mixture is then dispersed in the air and deposited to produce a mixture of approximately uniform thickness. These steps can be performed using a known deposition device including an agitator and a belt conveyor. The mixing ratio of kapok fiber and shellac resin is preferably in the range of 50% to 90% by weight of kapok fiber and 10% to 50% by weight of shellac resin. In other words, the weight ratio of shellac resin as binder 2 in the mixture is 10% to 50%. That is, the blending mass ratio of kapok fiber to shellac resin is preferably within the range of 50:50 to 90:10, and more preferably 70:30.

[0014] In step S12, multiple layers of the mixture are stacked to form a laminate. Specifically, as shown in FIG. 3, a predetermined number of fiber layers 5, each of which is divided into small pieces roughly the size of the opening 20a, are placed one by one into the opening 20a of the mold 20 and stacked. That is, multiple fiber layers 5 are stacked in a mille-feuille-like manner and filled into the mold 20. The mold 20 is a square-tube metal mold with openings 20a and 20b at the front and rear. When the fiber layers 5 are filled, a plug member 22, which serves as the bottom, is inserted into the opening 20b at the rear of the mold 20, as shown in FIG. 4. After a predetermined amount of fiber layers 5 is filled into the mold 20, a plug member 21 is inserted into the opening 20a, as shown in FIG. 4, and the stacked fiber layers 5 are pressed between the plug member 21 and the plug member 22.

[0015] In step S13, the mold 20 containing the laminated fiber layers 5 under pressure is heated. Specifically, as shown in Fig. 5, the mold 20 is placed in a heating furnace 30 and heated at approximately 200°C for 30 to 60 minutes. The heating temperature may be set appropriately within a range of 180°C to 220°C depending on the size of the buffer material 8, the number of pieces to be put into the heating furnace 30, etc. After heating, the mold 20 is removed and cooled to room temperature, and then the plug member 21 is removed, and the plug member 22 is pushed in, and the cushioning material 8 is taken out. In this way, the cushioning material 8 shown in FIG. 1 is completed. The density of the cushioning material 8 formed with the above blending ratio is 0.01 g / cm 3 More than 0.5g / cm 3 The range is as follows: As the buffer material 8, the kapok fibers are aligned in the direction in which the load is received.

[0016] In other words, the manufacturing method of the buffer material 8 includes the steps of: defibrating a material containing hollow fibers 1 to obtain hollow fibers; mixing kapok fibers as hollow fibers 1 with shellac resin as binder 2 to obtain a mixture; stacking the mixture into multiple fiber layers 5 to obtain a laminate; and heating and pressurizing the laminate to form the buffer material 8. The buffer material 8 is formed by heating and compressing a mixture of kapok fibers as hollow fibers 1 and shellac resin as binder 2 that binds the kapok fibers together.

[0017] ***Example*** Fig. 6 is a schematic diagram of a compressive stress measuring device. Fig. 7 is a graph showing compressive stress-strain characteristics, with strain (ε) on the horizontal axis and stress (N / cm) on the vertical axis. 2 ) is taken. Figure 8 is a graph showing the damping coefficient distortion characteristics, with the horizontal axis representing the strain (ε) and the vertical axis representing the damping coefficient (C).

[0018] The cushioning material 8 shown in FIG. 1 was manufactured by the above manufacturing method. The size of the cushioning material 8 was a length L of 8 cm, a width W of 4 cm, and a thickness T of 3 cm. The mass ratio of the kapok fiber to the shellac resin was 70:30, and the density of the cushioning material 8 was 0.06 g / cm. 3The density of conventional pulp-based cushioning materials was 0.13 g / cm 3 is. As a comparative sample, foamed polystyrene of the same size as the cushioning material 8 was used. The expansion ratio of the foamed polystyrene was set to 50 times. As shown in Fig. 6, the cushioning material 8 was set on a base 41 of a compressive stress measuring device 40, and was compressed from above by a compression jig 42 while measuring physical properties such as the compressive strength of the cushioning material 8. A known autograph (universal testing device) was used as the compressive stress measuring device 40. The physical properties of the foamed polystyrene of the comparative example were also measured using the compressive stress measuring device 40 in the same manner. Note that, before measuring using the autograph, the cushioning material was cut so that its length L was 3 cm, and then the measurement was carried out.

[0019] Graph 91 in Fig. 7 shows the compressive stress-strain characteristics of the foamed polystyrene of the comparative example. Graph 51 shows the compressive stress-strain characteristics of the cushioning material 8. Graph 91 and graph 51 are nearly overlapping, indicating that they have nearly similar characteristics. In other words, the cushioning material 8 has smooth compression characteristics that are nearly equivalent to those of the foamed polystyrene of the comparative example. 8 shows the cushioning coefficient distortion characteristics of the foamed polystyrene of the comparative example. Graph 52 shows the cushioning coefficient distortion characteristics of the cushioning material 8. Graph 92 and graph 52 are almost overlapping, and it can be seen that they have almost similar characteristics. That is, it is understood that the cushioning material 8 has substantially the same cushioning performance as the foamed polystyrene of the comparative example.

[0020] A drop test was also conducted in which a weight of 2.49 kg was dropped from a height of 65 cm onto the cushioning material 8. Although not shown in the figure, the drop impact waveform confirmed that the cushioning material 8 could buffer the maximum acceleration to about 60 G, which is equivalent to that of the foamed polystyrene used as a comparative example. In other words, the cushioning material 8 can be designed based on the same buffering theory as foamed polystyrene.

[0021] Furthermore, when the buffer material 8 was subjected to static pressure and left in a high-temperature, humid environment for a long period of time, the compressive creep strain was measured and found to be 3.5% or less, which meets the company's standard of 5% or less, confirming that the material has sufficient moisture resistance and durability. The static pressure was 0.01 MPa, the high-temperature, humid environment was 60°C, 90% RH, and the storage time was 120 hours.

[0022] As described above, the cushioning material 8 and the method for manufacturing the cushioning material 8 according to this embodiment can provide the following effects. The buffer material 8 is formed by heating and compressing a mixture of kapok fibers as hollow fibers 1 and shellac resin as binder 2 that binds the kapok fibers.

[0023] According to this, the kapok fiber and shellac resin, both of which are naturally derived materials, can provide a buffer material 8 with sufficient buffering performance. In addition, the density of the buffer material 8 is 0.06 g / cm 3 The density of conventional pulp-based cushioning materials is 0.13 g / cm 3 It is lightweight, weighing less than half the weight of conventional plastics. Furthermore, it has been confirmed to have sufficient moisture resistance. Therefore, it is possible to provide a cushioning material 8 that is environmentally friendly, lightweight, and has excellent moisture resistance.

[0024] The hollow fibers 1 are kapok fibers, and the binder 2 is shellac resin. This makes it possible to provide a buffer material 8 that is lightweight and has excellent moisture resistance, made from naturally occurring materials.

[0025] The fiber length of the kapok fiber as the hollow fiber 1 is 0.1 mm or more and 10.0 mm or less, which makes it possible to obtain a buffer material 8 having sufficient buffering performance.

[0026] The method for manufacturing the buffer material 8 includes the steps of: defibrating a material containing hollow fibers 1 to obtain hollow fibers; mixing kapok fibers as the hollow fibers 1 with shellac resin as the binder 2 to obtain a mixture; stacking multiple layers of fiber layers 5 obtained by dividing the mixture into small pieces to obtain a laminate; and heating and pressurizing the laminate to form the buffer material 8.

[0027] This allows the buffer material 8 to be manufactured through four steps: fiberization, mixing, lamination, and heat compression, resulting in high manufacturing efficiency.

[0028] Embodiment 2 ***Different forms of cushioning*** FIG. 9 is a perspective view of a cushioning material according to the second embodiment, and corresponds to FIG. In the above embodiment, the cushioning material 8 is described as having a rectangular parallelepiped shape, but this is not limited thereto and any shape suitable for the application may be used. Hereinafter, the same parts as those in the above embodiment will be assigned the same reference numerals, and duplicated explanations will be omitted.

[0029] The cushioning material 18 of this embodiment shown in Figure 9 has a rectangular parallelepiped outer shape with a bottle-shaped recess 18b in the center. The recess 18b is, for example, a depression modeled after a sake bottle. In other words, the cushioning material 18 is a presentation box that stores and protects sake bottles. Furthermore, natural bamboo charcoal is added to the cushioning material 18 as a coloring agent during the mixing process. This gives the overall color a darker tone, making it a presentation box that makes the sake bottles stand out. This cushioning material 18 can provide an environmentally friendly presentation box that protects the liquor bottles with its cushioning properties and makes the liquor bottles stand out visually. Note that the cushioning material is not limited to presentation boxes for liquor bottles, and can be used for a variety of purposes, such as building blocks for children's toys, smartphone cases, cushioning for helmets, and cushioned envelopes.

[0030] Furthermore, kapok fiber and shellac resin are water-repellent and float on water, so the above-mentioned buffer material can also be used as buoyancy material in life jackets, swim rings, etc. Also, kapok fiber has excellent oil absorption properties, so the above-mentioned buffer material can be used as an oil-absorbing sponge with buffer properties, or as an oil belt in the event of an oil spill at sea. The cushioning material is also highly recyclable, and used cushioning material 8 can be cut into small pieces and reused as recycled material. Specifically, in the mixing process, the recycled material is mixed with virgin material, and then the mixture is placed in a mold, laminated, and heated and compressed to produce recycled cushioning material.

[0031] In the above embodiment, the hollow fibers 1 are described as kapok fibers, but the present invention is not limited to this and any hollow fibers similar to kapok fibers that are naturally derived may be used. Furthermore, although the binder 2 has been described as shellac resin, it is not limited to this and may be any naturally occurring substance that has similar binding properties to shellac resin, such as starch or pine resin. In the above mixing step, it is also possible to add a core-sheath material, a colorant, a condensation inhibitor, a flame retardant, etc. These additives are preferably naturally occurring substances. [Explanation of symbols]

[0032] 1...hollow fiber, 2...binder, 5...fiber layer, 8...cushioning material, 18...cushioning material, 18b...recess, 20...mold, 20a...opening, 20b...opening, 21...plug member, 22...plug member, 30...heating furnace, 40...compression stress measuring device, 41...base, 42...compression jig, 51...graph, 52...graph, 91...graph, 92...graph.

Claims

1. A mixture of hollow fibers and a binder that binds the hollow fibers is heated and compressed to form a molded product. Buffer material.

2. The hollow fibers are kapok fibers, and the binder is shellac resin. The cushioning material according to claim 1 .

3. The length of the hollow fiber is 0.1 mm or more and 10.0 mm or less. The cushioning material according to claim 2.

4. The weight ratio of the binder in the mixture is 10% or more and 50% or less. The cushioning material according to claim 3.

5. A step of defibrating a material containing hollow fibers to obtain the hollow fibers; mixing the hollow fibers with a binder to obtain a mixture; a step of laminating a plurality of layers of the mixture to obtain a laminate; and molding the cushioning material by heating and pressurizing the laminate. Manufacturing method of cushioning material.

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