JP7400286B2 - Fiber structure and fiber structure block - Google Patents

Description

The present invention relates to a fiber structure and a fiber structure block.

BACKGROUND ART Conventionally, a method of manufacturing a plate-like material made of fiber by laminating nonwoven fabrics is known (for example, see Patent Document 1).

International Publication No. 2007/018051

Packaging materials using fibers have the advantage of having a lighter environmental impact than packaging materials made of expanded polystyrene. However, it has been difficult to provide packaging materials using fibers with a shock-absorbing effect.

One aspect of achieving the above object is a fiber structure that includes cellulose fibers arranged such that the main fiber orientation direction is a first direction, and a crosslinking material that binds the plurality of cellulose fibers to each other. , the fibrous structure is such that the first direction forms an angle of 45 degrees or less with respect to the direction of an external force applied to the outer surface of the fibrous structure from the outside.

One aspect of achieving the above object is a fiber structure that includes cellulose fibers arranged such that the main fiber orientation direction is a first direction, and a crosslinking material that binds the plurality of cellulose fibers to each other. , a fibrous structure having a accommodating space for accommodating an object, the first direction forming an angle of 45 degrees or less with respect to the direction of an external force applied from outside the fibrous structure toward the accommodating space; It is.

In the above fibrous structure, the first direction is a direction forming an angle of 45 degrees or less with respect to the direction of an external force applied directly to the outer surface of the fibrous structure or via an external member. Good too.

The above-mentioned fibrous structure may have a plurality of the outer surfaces, and the first direction may form an angle of 45 degrees or less with respect to a normal line of any one of the outer surfaces.

In the above-mentioned fiber structure, the first direction may be configured to form an angle of 45 degrees or less with respect to a normal to the largest outer surface among the plurality of outer surfaces.

In the above fiber structure, the crosslinked material may include a first resin and a second resin made of a material different from the first resin.

The fiber structure may include a material different from the cellulose fibers and the crosslinked material.

The above-mentioned fibrous structure may be composed of a flat plate structure in which the cellulose fibers are laminated, and the first direction may be a direction included in a surface of the flat plate structure.

One aspect of achieving the above object is to combine a plurality of fiber structures including cellulose fibers arranged such that the main fiber orientation direction is a first direction, and a crosslinking material that binds the plurality of cellulose fibers to each other. and has a storage space for storing an object, and the fiber structure is configured such that the first direction makes an angle of 45 degrees or less with respect to the direction of an external force applied from the outside toward the storage space. , are arranged fiber structure blocks.

FIG. 2 is a configuration diagram of a sheet manufacturing device. Flowchart showing the manufacturing process of the fiber structure. An explanatory diagram of fiber orientation directions in a sheet. An explanatory diagram of fiber orientation directions in a sheet. FIG. 3 is a diagram showing the configuration of a test piece for testing buffer function. A chart showing test results of buffer function. Schematic diagram showing the state of expression of buffering function. FIG. 2 is a perspective view showing an example of a fiber structure. The perspective view which shows another example of a fiber structure. FIG. 9 is a sectional view taken along line QQ in FIG. 9; The perspective view which shows yet another example of a fiber structure. The figure which shows the example of a structure of a composite sheet. The figure which shows the example of a structure of a composite sheet. The figure which shows the example of a structure of a composite sheet. The figure which shows the example of a structure of a composite sheet. FIG. 7 is a schematic diagram showing a molding section in a second embodiment. FIG. 7 is a perspective view showing an example of a fiber structure according to a second embodiment. FIG. 18 is a sectional view taken along line RR in FIG. 17. FIG. 7 is a perspective view showing another example of the fiber structure of the second embodiment. FIG. 7 is a perspective view showing yet another example of the fiber structure of the second embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail using the drawings. Note that the embodiments described below do not limit the content of the present invention described in the claims. Furthermore, not all of the configurations described below are essential components of the present invention.

[1. First embodiment]
[1-1. Sheet manufacturing equipment]
FIG. 1 is a diagram showing the configuration of a sheet manufacturing apparatus 100. The sheet manufacturing apparatus 100 manufactures a sheet S1 that is a material for a fiber structure to which the present invention is applied.

The sheet manufacturing apparatus 100 includes a supply section 10, a coarse crushing section 12, a defibrating section 20, a sorting section 40, a first web forming section 45, a rotating body 49, a mixing section 50, a dispersing section 60, a second web forming section 70, It includes a web conveying section 79, a processing section 80, and a cutting section 90.

The sheet manufacturing apparatus 100 manufactures the sheet S1 by converting a raw material MA containing fibers described later, such as wood pulp material, kraft pulp, waste paper, and synthetic pulp, into fibers.
The raw material MA may be anything as long as it contains cellulose fibers. For example, wood pulp materials, kraft pulp, waste paper, synthetic pulp, etc. can be used. Wood-based pulp materials include mechanical pulp made by mechanical processing such as ground pulp, chemical pulp made by chemical processing, semi-chemical pulp produced by using both of these processes together, and chemical pulp made by using both of these processes. Examples include ground pulp. Moreover, either bleached pulp or unbleached pulp may be used. Examples include virgin pulp such as N-BKP (bleached softwood kraft pulp) and L-BKP (bleached hardwood kraft pulp), bleached chemithermomechanical pulp (BCTMP), and the like. Alternatively, nanocellulose fiber (NCF) may be used. Waste paper is used paper such as printed PPC (Plain Paper Copy) paper, magazines, newspapers, and the like. Examples of synthetic pulp include SWP manufactured by Mitsui Chemicals, Inc. SWP is a registered trademark.

Further, the raw material MA may include carbon fiber, metal fiber, thixotropic fiber in addition to the above-mentioned wood pulp material, waste paper, synthetic pulp, etc., or as a substitute for these. Therefore, the raw material MA may be a mixture of a plurality of materials among the above-mentioned wood pulp materials, waste paper, synthetic pulp, carbon fibers, metal fibers, and thixotropic fibers.
The raw material MA, the defibrated material MB, and the fiber material MC described below can be said to be materials containing fibers.

The supply section 10 supplies the raw material MA to the coarse crushing section 12 . The coarse crushing section 12 is a shredder that shreds the raw material MA using a coarse crushing blade 14. The raw material MA shredded by the crushing section 12 is conveyed to the defibrating section 20 through a pipe.

The defibrating section 20 dryly defibrates the pieces cut by the coarse crushing section 12 into a defibrated material MB. Defibration is a process of unraveling the raw material MA in which a plurality of fibers are bound into one or a small number of fibers. Dry processing refers to processing such as defibration in air or the like rather than in a liquid. The defibrated material MB contains the fibers contained in the raw material MA. Furthermore, the defibrated material MB may contain substances other than the fibers contained in the raw material MA. For example, when waste paper is used as the raw material MA, the defibrated material MB contains components such as resin particles, colorants such as ink and toner, bleed prevention material, and paper strength enhancer.

The defibrating section 20 is, for example, a mill that includes a cylindrical stator 22 and a rotor 24 that rotates inside the stator 22, and defibrates the coarse pieces by sandwiching them between the stator 22 and the rotor 24. do. The defibrated material MB is sent to the sorting section 40 through piping.

The fibers contained in the raw material MA or the fibers contained in the defibrated material MB have a fiber length of 0.1 mm or more and 100 mm or less, and preferably 0.5 μm or more and 50 m or less. Further, the fiber diameter of these fibers is from 0.1 μm to 1000 μm, preferably from 1 μm to 500 μm. Further, these fibers may include a plurality of types of fibers, and may include fibers having different fiber lengths and/or fiber diameters. The fiber length and fiber width can be determined, for example, by measuring with a fiber tester (manufactured by Lorentzen & Wettre) and calculating a length-weighted average value.

The sorting section 40 includes a drum section 41 and a housing section 43 that accommodates the drum section 41. The drum section 41 is a sieve having openings such as a net, a filter, or a screen, and is rotated by the power of a motor (not shown). The defibrated material MB is loosened inside the rotating drum section 41, passes through the opening of the drum section 41, and descends. Among the components of the defibrated material MB, those that do not pass through the opening of the drum section 41 are conveyed to the defibrated section 20 through the pipe.

The first web forming section 45 includes an endless mesh belt 46 having a large number of openings. The first web forming section 45 produces the first web W1 by depositing fibers and the like descending from the drum section 41 on the mesh belt 46. Among the components that have descended from the drum section 41, those smaller than the openings of the mesh belt 46 pass through the mesh belt 46 and are removed by suction by the suction section 48. As a result, among the components of the defibrated material MB, short fibers, resin particles, ink, toner, anti-bleeding agent, etc. that are not suitable for manufacturing the sheet S1 are removed.

A humidifier 77 is disposed along the movement path of the mesh belt 46, and the first web W1 deposited on the mesh belt 46 is humidified with mist-like water or highly humid air.
The first web W1 is conveyed by the mesh belt 46 and comes into contact with the rotating body 49. The rotating body 49 uses a plurality of blades to divide the first web W1 into fiber material MC. The fiber material MC is conveyed to the mixing section 50 through the pipe 54.

The mixing section 50 includes an additive supply section 52 that adds the additive material AD to the fiber material MC, and a mixing blower 56 that mixes the fiber material MC and the additive material AD. The additive material AD will be described later.
The mixing blower 56 generates an air current in the pipe 54 through which the fiber material MC and the additive material AD are conveyed, mixes the fiber material MC and the additive material AD, and transports the mixture MX to the dispersion section 60.

The dispersion section 60 includes a drum section 61 and a housing section 63 that accommodates the drum section 61. The drum section 61 is a cylindrical sieve configured similarly to the drum section 41, and is driven and rotated by a motor (not shown). As the drum section 61 rotates, the mixture MX is loosened and moves down inside the housing section 63.

The second web forming section 70 includes an endless mesh belt 72 having a large number of openings. The second web forming section 70 deposits the mixture MX descending from the drum section 61 on the mesh belt 72 to produce the second web W2. Among the components of the mixture MX, those smaller than the openings of the mesh belt 72 pass through the mesh belt 72 and are sucked by the suction section 76 .

A humidifier 78 is disposed along the movement path of the mesh belt 72, and the second web W2 deposited on the mesh belt 72 is humidified with mist-like water or highly humid air.

The second web W2 is peeled off from the mesh belt 72 by the web conveyance section 79 and conveyed to the processing section 80. The processing section 80 includes a pressure section 82 and a heating section 84. The pressure section 82 sandwiches the second web W2 between a pair of pressure rollers and presses it with a predetermined nip pressure to form a pressed sheet SS1. The heating unit 84 applies heat to the pressed sheet SS1 between the pair of heating rollers. As a result, the fibers included in the pressurized sheet SS1 are bound by the resin contained in the additive material AD, and the heated sheet SS2 is formed. The heated sheet SS2 is conveyed to the cutting section 90.

The cutting unit 90 cuts the heated sheet SS2 in a direction intersecting with the conveyance direction FE and/or in a direction along the conveyance direction FE, thereby manufacturing a sheet S1 of a predetermined size. The sheet S1 is stored in the discharge section 96.

The sheet manufacturing apparatus 100 includes a control device 110. The control device 110 controls each part of the sheet manufacturing apparatus 100 including the defibrating section 20, the additive supply section 52, the mixing blower 56, the dispersing section 60, the second web forming section 70, the processing section 80, and the cutting section 90. Then, the method for manufacturing the sheet S1 is executed. Further, the control device 110 may control the operations of the supply section 10, the sorting section 40, the first web forming section 45, and the rotating body 49.

The additive material AD crosslinks a plurality of fibers, thereby bonding the fibers to each other and forming the fibers into a sheet shape. The additive material AD includes a resin that functions as a binding material that binds fibers together, and specifically includes a thermoplastic resin and/or a thermosetting resin. It may also contain a thermoplastic core-sheath resin. In addition to the above resin, the additive material AD may also contain a colorant, an aggregation inhibitor, a flame retardant, and the like.

As the thermoplastic resin, for example, a resin having a melting temperature of 60° C. or more and 200° C. or less and a deformation temperature of 50° C. or more and 180° C. or less can be used. Here, the deformation temperature can also be called the glass transition temperature. As the thermoplastic resin, petroleum-derived resins, biomass plastics, biodegradable plastics, and natural resins can be used. Here, petroleum-derived resins include, for example, polyolefin resins, polyester resins, polyamide resins, polyacetals, polycarbonates, modified polyphenylene ethers, cyclic polyolefins, ABS resins, polystyrene, polyvinyl chloride, polyvinyl acetate, polyurethane, and Teflon. Examples include resin, acrylic resin, polyphenylene sulfide, polytetrafluoroethylene, polysulfone, polyethersulfone, amorphous polyaryate, liquid crystal polymer, polyetheretherketone, thermoplastic polyimide, and polyamideimide. Examples of biomass plastics and biodegradable plastics include polylactic acid, polycaprolactone, modified starch, polyhydroxybutyrate, polybutylene succinate, polybutylene succinate, and polybutylene succinate adipate. Examples of natural resins include rosin. Teflon is a registered trademark. Examples of the thermosetting resin include phenol resin, epoxy resin, vinyl ester resin, unsaturated polyester, and natural thermosetting resin shellac. Additive material AD contains one or more of the above resins. For example, a plurality of resins having different glass transition temperatures Tg and melting points may be included.

Further, the resin contained in the additive material AD is preferably in the form of particles or fibers. When a particulate resin is used, particles with a weight average particle diameter of 0.1 μm or more and 120 μm or less are more preferable, and particles with a weight average particle diameter of 1 μm or more and 50 μm or less are even more preferable.

In addition to the resin described above, the additive material AD may also include a resin material or a polymer material that forms a porous structure when heated. These materials are, for example, thermally expandable materials that expand upon heating. A so-called foam material can be used as the thermally expandable material. The thermally expandable material is preferably in the form of particles, and the thermally expandable material shaped into particles can be referred to as expanded particles. The particle size of the expanded particles contained in the additive material AD is preferably 0.5 μm or more and 1000 μm or less, and more preferably 1 μm or more and 300 μm or less in weight average particle size before foaming. More preferably, the weight average particle diameter after foaming is 5 μm or more and 1000 μm or less, most preferably 5 μm or more and 800 μm or less.

As the foamed particles, for example, a capsule-shaped thermally expandable capsule that expands due to heat, or a foamed material mixture particle in which a thermally expandable material is mixed can be used. Examples of thermally expandable capsules include Advancel manufactured by Sekisui Chemical Co., Ltd., Kureha Sphere manufactured by Kureha Co., Ltd., Expancel manufactured by Akzo Nobel Co., Ltd., and Matsumoto Microsphere manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd. . Advancecel, Kureha, Expancel, Expancel, and Matsumoto Microsphere are each registered trademarks. The foaming material mixed particles are a particulate preparation manufactured by mixing a thermally expandable material with the above-mentioned thermoplastic resin. Here, the foaming material is, for example, azodicarbonamide, N,N'-dinitrosopentamethylenetetramine, 4,4'-oxybis(benzenesulfonylhydrazide, N,N'-dinitrosopentamethylenetetramine, azodicarbonamide, Sodium hydrogen carbonate or the like can be used.

When the surface of the foamed particles is covered with a resin, it is preferable that the coverage of the foamed particles with the resin is 10% or more and 100% or less.

In addition to the above-mentioned resin, the additive material AD may contain an inorganic filler, a rigid fiber, and a thixotropic fiber as a reinforcing material that makes the crosslinked structure in which fibers are bound together more rigid. As the inorganic filler material, for example, calcium carbonate, mica, etc. can be used. As the rigid fiber, for example, carbon fiber, glass fiber, or metal fiber can be used. Also, high stiffness fibers such as Kevlar or other aramid fibers can be used. Kevlar is a registered trademark. Examples of thixotropic fibers include cellulose nanofibers.

Moreover, the additive material AD may be formed into a composite resin material powder by kneading and pulverizing the components such as the resin, foamed particles, reinforcing material, etc. mentioned above.

[1-2. Manufacturing process of fiber structure]
FIG. 2 is a flowchart showing the manufacturing process of a fiber structure to which the present invention is applied. The manufacturing process shown in FIG. 2 includes a process of manufacturing the sheet S1 using the sheet manufacturing apparatus 100.

Step SA1 is a crushing step of crushing the raw material MA, and corresponds to, for example, the process by the crushing section 12 of the sheet manufacturing apparatus 100. The coarse crushing process is a process of cutting the raw material MA into pieces smaller than a predetermined size. The predetermined size is, for example, 1 cm to 5 cm square. When raw material MA is supplied in a cut state, step SA1 can be omitted.

Step SA2 is a defibration step, and corresponds to processing by the defibration section 20 of the sheet manufacturing apparatus 100, for example.
Step SA3 is a process of taking out materials mainly consisting of fibers from the defibrated material MB, and is referred to as a separation process. The separation step is a step in which particles such as resin and additives are separated from the defibrated material MB containing fibers and resin particles, and a material whose main component is fibers is taken out. The separation process corresponds to, for example, a process that includes the sorting section 40 and the rotating body 49 of the sheet manufacturing apparatus 100.

If the raw material MA supplied in step SA1 does not contain particles etc. that would affect the production of sheet S1, or if there is no need to remove particles etc. from the components contained in the raw material MA, the separation step of step SA3 is omitted. can. In this case, the defibrated material MB is used as it is as the fiber material MC.

Step SA4 is an addition step, and is a step of adding additive material AD to the fiber material MC separated in step SA3. The addition process corresponds to processing by the additive supply unit 52 of the sheet manufacturing apparatus 100, for example.

Step SA5 is a mixing step, in which the fiber material MC and the additive material AD are mixed to produce a mixture MX. The mixing process corresponds to processing by the mixing section 50 of the sheet manufacturing apparatus 100, for example.

Step SA6 is a sieving process, in which the mixture MX is sieved, dispersed in the atmosphere, and lowered. The sieving process corresponds to processing by the dispersion section 60 of the sheet manufacturing apparatus 100, for example.

Step SA7 is a deposition step in which the mixture MX that falls in the sieving step of Step SA6 is deposited to form a web. The deposition process corresponds to, for example, a process of forming the second web W2 by the second web forming section 70 of the sheet manufacturing apparatus 100.

Step SA8 is a pressurizing and heating step, in which the web is pressurized and heated. The heating and pressing process corresponds to, for example, a process in which the processing unit 80 of the sheet manufacturing apparatus 100 heats and presses the second web W2, and forms the sheet S1 through the pressurized sheet SS1 and the heated sheet SS2. . Although the order of pressurization and heating in the pressurization and heating step is not limited, it is preferable that pressurization is performed first.

Step SA9 is a molding step of molding a fibrous structure using the sheet S1. In the forming process, a fibrous structure having a box shape or the like is created by connecting, bonding, adhering, etc. the sheets S1. In the forming process, in order to join the plurality of sheets S1, methods such as adhesion using an adhesive material, thermal fusion using melted thermoplastic resin, skewering using a core material, and binding using fastening parts can be used. Simple bonding based on the roughness of the fiber surface may be adopted.

The manufacturing process shown in FIG. 2 is not limited to the case where the sheet manufacturing apparatus 100 is used, and it is of course possible to use the sheet S1 manufactured by another apparatus. Moreover, the manufacturing process shown in FIG. 2 as a manufacturing method of sheet S1 is an example, and the fiber structure to which the present invention is applied may be molded using sheet S1 manufactured by other methods.

[1-3. Fiber orientation direction of sheet]
FIG. 3 is an explanatory diagram of the fiber orientation direction in the sheet S1.
As indicated by the symbol A in FIG. 3, the sheet S1 is a sheet having a thin planar shape or flexibility. The sheet S1 is obtained by sieving and depositing a mixture of fibers contained in a defibrated material obtained by defibrating the raw material MA and a particulate and/or fibrous resin. Therefore, assuming an X-Y-Z orthogonal coordinate system in which the surface of the sheet S1 is the X-Y plane, the fibers F included in the sheet S1 are oriented in random directions in the X-Y plane, while in the Z direction , the direction is along the surface of the sheet S1. The respective fibers F included in the sheet S1 are stacked and overlap each other, or are in point contact with other fibers F, so as to have a structure having a certain orientation.

Therefore, in the sheet S1, since the fibers F are along the XY plane of the sheet S1, the XY plane can be said to be the orientation direction of the fibers F.

Furthermore, the direction of the fibers F may be unevenly distributed within the XY plane of the sheet S1. When the sheet S1 is manufactured by the sheet manufacturing apparatus 100, the mixture MX is deposited on the mesh belt 72 as the cylindrical drum section 61 rotates. In this deposition process (step SA7), the fibers included in the mixture MX tend to be oriented in the direction of rotation of the drum section 61. Therefore, the second web W2 tends to contain many fibers F oriented along the rotational direction of the drum portion 61. Therefore, the sheet S1 also contains many fibers F that are oriented in the rotation direction of the drum portion 61.

Here, the direction of the fibers F is indicated by the symbol B in FIG. Usually, the fibers F have an elongated shape. The lengthwise size of the fibers F can be referred to as a fiber length L1, and the widthwise size of the fibers F can be referred to as a width L2. The width L2 corresponds to the fiber diameter. In this embodiment, the direction of the length L1 of the fibers F is referred to as the orientation direction DF. The orientation direction DF indicates the direction of one fiber F.

By combining the orientation directions DF of the plurality of fibers F included in the sheet S1, the fiber orientation direction DS in the sheet S1 can be determined. For example, a predetermined number of fibers F are extracted from the fibers F constituting the sheet S1, the average direction of the orientation directions DF of the plurality of extracted fibers F is determined, and the determined direction is set as the fiber orientation direction DS of the sheet S1. be able to.
As a method for determining the fiber orientation direction DS, the present inventors used a digital microscope (manufactured by Keyence Corporation: VHX5000) at a magnification of 200 to 500 times to examine the sheet S1 or the fiber structure or fibers described below. The surface of the structure block was observed. The inventors randomly selected 50 fibers F from the fibers F observed with a digital microscope, measured the orientation direction DF based on the observed surface, calculated the average value, and calculated the fiber orientation direction DS. And so.

More specifically, the number of fibers F whose orientation direction DF is in a predetermined direction is T1, the number of fibers F whose orientation direction DF is in a direction different from the predetermined direction is T2, and by calculating T1/T2, the predetermined The ratio of the number of fibers in the direction can be determined. Then, the predetermined direction in which the ratio of the number of fibers is the largest can be set as the fiber orientation direction DS of the sheet S1.

An example of the fiber orientation direction DS in the sheet S1 is indicated by the symbol C in FIG. The size of the sheet S1 in the Z direction, which indicates the thickness, is smaller than the size in the XY plane. Therefore, in most cases, the fiber orientation direction DS of the sheet S1 is in the XY plane, as shown in FIG. The fiber orientation direction DS includes a fiber orientation direction DS1 parallel to the Y axis and a fiber orientation direction DS2 parallel to the X axis, as well as fiber orientation directions DS3, DS4 tilted with respect to the It can be a direction.

Furthermore, there is a method in which the orientation direction DF of many fibers F matches the fiber orientation direction DS of the sheet. FIG. 4 is an explanatory diagram of the fiber orientation direction DS in the sheet S2. The sheet S2 is a member cut out along the cut surface CU so as to have a sheet shape from the laminate 201 in which a plurality of sheets S are laminated.

The laminate 201 is formed by laminating a plurality of sheets S, or by applying a bonding process to a state in which a plurality of layers are overlapped by folding the sheets S. The bonding treatment includes press treatment, pressure treatment, heat treatment, heat treatment in an oven or furnace, bonding treatment with an adhesive, and the like.

In the sheet S2, the fibers F extending in the X direction are cut short by cutting the laminate 201 along the YZ plane. Further, the laminate 201 does not include long fibers F extending in the Z direction. Therefore, the fiber orientation direction DS of the sheet S2 is parallel to the Y direction in the figure, and the fibers F that are not along the fiber orientation direction DS are almost short fibers.
In the sheet S2, the orientation direction DF of many fibers F is parallel to the fiber orientation direction DS, and the orientation direction DF is well arranged.

[1-4. Buffer function of fiber structure]
Here, the buffering function of the fiber structure and the fiber orientation direction DS will be explained.
FIG. 5 is a diagram showing the configuration of a test piece used for testing the buffer function. Here, the buffering function refers to the effect of absorbing or mitigating the impact when an impact is applied to the fibrous structure formed using the sheet S, so that the impact is not transmitted from the fibrous structure to other objects. say.

The present inventors produced a test piece 210 and a test piece 220 using the sheet S1 or the sheet S2, and measured the stress and compressibility when an external force was applied to the test pieces 210 and 220. In addition, a test piece 230 made of expanded polystyrene was produced as a comparison object, and the same measurements as the test pieces 210 and 220 were performed. FIG. 5 shows test pieces 210, 220, and 230, and the direction in which external force is applied during the test is indicated by PW.

The test piece 210 has a substantially rectangular parallelepiped shape and has a surface 211 to which external force PW is applied during testing. The fiber orientation direction DS in the test piece 210 intersects the direction of the external force PW at an angle of more than 45 degrees, and is typically perpendicular. In another expression, the fiber orientation direction DS is perpendicular to the normal to the surface 211. The density of the test piece 210 was 0.15, and the resin content of the additive material AD contained in the test piece 210 was 30% by weight.

The test piece 220 has a substantially rectangular parallelepiped shape and has a surface 221 to which external force PW is applied during testing. The fiber orientation direction DS in the test piece 220 has an angle of 45 degrees or less with the direction of the external force PW, and is typically parallel to the direction. In another expression, the fiber orientation direction DS is parallel to the normal to the surface 211. The density of the test piece 220 was 0.15, and the resin content of the additive material AD contained in the test piece 220 was 30% by weight.
The test piece 210 and the test piece 220 can be manufactured by stacking and joining sheets S1 or S2.

The test piece 230 is a substantially rectangular parallelepiped object made of expanded polystyrene, and has a surface 231 to which an external force PW is applied during the test.

FIG. 6 is a chart showing the test results of the buffer function. The horizontal axis in FIG. 5 shows the compressibility, and the vertical axis shows the stress. The compression ratio indicates the amount by which the test pieces 210, 220, 230 are compressed in the direction of the external force PW by applying the external force PW, as a ratio to the size of the test pieces 210, 220, 230. The stress is the stress of the test pieces 210, 220, 230 resisting the external force PW.
Curve 251 in FIG. 6 is the compressibility-stress curve of test piece 210, and curve 252 is the compressibility-stress curve of test piece 220. Curve 253 is the compressibility-stress curve of test piece 230.

Further, FIG. 6 shows a curve 254 that is a compressibility-stress curve of a test piece as a control example. A curve 254 is an example in which a test piece is used in which the orientation direction DF of the fibers F is random, that is, the orientation direction DF is not biased in a specific direction or is slightly biased. This test piece is composed of a sheet S1 manufactured at low density by the sheet manufacturing apparatus 100 so that the orientation direction DF is dispersed, has a density of 0.09, and contains 33% by weight of the resin as the additive material AD.

In curves 251 and 254, the stress increases as the compression rate increases. In other words, as the surface 211 is depressed by the external force PW, the stress resisting the external force PW increases, so it is compressed by the external force PW and becomes denser.

In contrast, in curve 253, the increase in stress with respect to the increase in compressibility is small. In other words, even if the test piece 230 made of expanded polystyrene is deformed by the external force PW and the surface 231 is depressed, the stress tends not to increase. Curve 252 shows a similar tendency as curve 253 as a whole, and shows a tendency for stress to increase less with increasing compressibility.

From the results of curves 252 and 253, test piece 220 and test piece 230 deform when external pressing force or impact is applied, but they tend not to increase stress or do not easily increase stress during the deformation process. Therefore, if an external force or impact is applied to a material similar to that of the test piece 220 or test piece 230 used as a packaging material or storage container to contain an object, the packaging material or storage container may be deformed or destroyed. , it can be said that it is difficult to apply force to the stored object. Storage containers made of expanded polystyrene have been evaluated to have excellent buffering properties, and the test piece 220 is similarly suitable for manufacturing packaging materials and storage containers that have excellent buffering properties. On the other hand, the results of curve 251 indicate that when an external force or impact is applied to an object housed in a packaging material or storage container made of the same material as test piece 210, the object will also be affected by the force. It can be said that it is easy to receive shock.

FIG. 7 is a schematic diagram showing the state of development of the buffer function of the test pieces 210, 220, and 230.
As shown in FIG. 7, it is considered that the test piece 210 was compressed by the external force PW in a state in which the fibers F overlapped, so that the higher the compression ratio, the higher the hardness and rigidity, and the stress was developed. On the other hand, in the test piece 220, the fibers F subjected to the external force PW moved in the DV direction to avoid the external force PW, so that the entire test piece 220 was significantly deformed and yielded to the external force PW. In this case, as the test piece 220 deforms, the impact energy of the external force PW is consumed in order to dissociate the fibers included in the test piece 220 from the state bonded by the binding material, so the external force PW is relaxed and absorbed. Ru. Moreover, since the test piece 220 deforms in a direction different from the external force PW, the test piece 220 is difficult to become denser even if the external force PW is applied. Therefore, stress is less likely to increase due to deformation. In addition, in the test piece 230 made of expanded polystyrene, individual styrene resin grains are crushed by the external force PW, so the rigidity of the test piece 230 as a whole does not change, and it is considered that stress is unlikely to increase.

In this way, in a fiber structure using sheet S1 or sheet S2, when the fiber orientation direction DS is parallel or close to parallel to the direction in which external force PW or impact is applied, it is possible to provide excellent cushioning like a Styrofoam container. function can be realized.
According to the findings of the inventors, a high buffering function can be obtained when the fiber orientation direction DS forms an angle of -45 degrees or more and +45 degrees or less with respect to the direction in which external force PW or impact acts.

In the following description, if the sheet S1 and the sheet S2 are not distinguished, they will be referred to as a sheet S. That is, various structures constructed using the sheet S in the following description may be manufactured using the sheet S1 as a material, or may be manufactured using the sheet S2 as a material.

[1-5. Configuration example of fiber structure]
Here, a configuration example of a fiber structure using the sheet S will be explained.
FIG. 8 is a perspective view of a fiber structure 300 as a configuration example using the sheet S. The fiber structure 300 is a substantially rectangular box having a bottom surface 301, side surfaces 302, 303, 304, 305, and a top surface 306.

At least one of the side surfaces 302, 303, 304, and 305 is configured using the sheet S. More preferably, two or more of the side surfaces 302, 303, 304, and 305 are configured using the sheet S, and even more preferably, all four sides are configured using the sheet S. In addition, when the several surface of the fiber structure 300 is comprised by the sheet|seat S, sheet|seat S1 and sheet|seat S2 may be used together.

On the other hand, the bottom surface 301 and the top surface 306 may be formed of the sheet S. Further, any material other than the sheet S may be used as long as it has rigidity; for example, a synthetic resin sheet or board, paper, wood, or metal board may be used.
Further, in FIG. 8, the fiber orientation direction DS of the bottom surface 301, the side surfaces 302, 303, 304, 305, and the top surface 306 is indicated by arrows.

The inside of the fiber structure 300 is a storage space for storing objects. The fiber structure 300 can exhibit a buffering effect against the external force PW applied from outside the fiber structure 300, attenuate the external force PW, and protect the stored object. Here, the external force PW is an impact force or a pressing force, and may include both.

FIG. 8 illustrates a case where an external force PW is applied from the outside toward the bottom surface 301. In this example, the bottom surface 301 corresponds to the outer surface to which the external force PW is applied. External force PW is applied to the side surfaces 302, 303, 304, and 305 via the bottom surface 301. Furthermore, when the external force PW is applied to the peripheral edge of the bottom surface 301, it can be said that the external force PW is applied directly to the side surfaces 302, 303, 304, and 305.

Here, the fiber orientation directions DS of the side surfaces 302, 303, 304, and 305 all form an angle of approximately 0 degrees with respect to the external force PW. Therefore, as described above regarding the test piece 220, the side surfaces 302, 303, 304, and 305 exert a buffering effect against the external force PW, and can attenuate the external force PW.
The direction of the external force PW when the buffering effect is exerted is not limited to the example shown in FIG. 8 . That is, when external force PW is applied at an angle of 45 degrees or less with respect to the normal to bottom surface 301, the side surfaces 302, 303, 304, and 305 exert a buffering effect against this external force PW.

FIG. 8 shows an example in which the bottom surface 301 and/or the top surface 306 are made of a sheet S. In this example, the fiber orientation direction DS of the bottom surface 301 and the fiber orientation direction DS of the top surface 306 are oriented in the same direction. Therefore, when an external force PW is applied from a direction within 45 degrees to the normal line of the side surface 303 or the side surface 305, the bottom surface 301 and/or the top surface 306 exerts a buffering effect.

FIG. 9 is a perspective view showing a fiber structure 310 as another example of the structure of the fiber structure using the sheet S. FIG. 10 is a sectional view taken along the line QQ in FIG. 9, and shows a cross section of the fiber structure 310.

The fiber structure 310 is a substantially rectangular box having a bottom surface 311, side surfaces 312, 313, 314, 315, and a top surface 316. An internal structure 320 is arranged inside the fiber structure 310. The internal structure 320 is a substantially rectangular box having a bottom surface 321, side surfaces 322, 323, 324, 325, and a top surface 326. The internal structure 320 is supported on the bottom of the fiber structure 310 via slope members 331, 332, 333, and 334. A bottom surface 321 of the internal structure 320 is located away from the bottom surface 311.

The bottom surface 311, side surfaces 302, 303, 304, 305, and top surface 306 of the fiber structure 310 may be made of a material other than the sheet S as long as it has rigidity; for example, a synthetic resin sheet or plate, It may be a paper, wood or metal plate. These surfaces may be composed of sheets S.

At least one surface of the slope members 331, 332, 333, and 334 is configured using a sheet S. More preferably, two or more sides, and even more preferably all four sides, are made up of sheets S. Note that when a plurality of surfaces of the slope members 331, 332, 333, and 334 are composed of sheets S, the sheets S1 and S2 may be used in combination.
In this embodiment, an example is shown in which all of the slope members 331, 332, 333, and 334 are made of sheets S, and the fiber orientation direction DS of each slope member 331, 332, 333, and 334 is indicated by an arrow in the figure.

The internal structure 320 constitutes a storage space that stores an object. The objects housed in the internal structure 320 are supported by slope members 331, 332, 333, and 334 via the bottom surface 321.

The fiber structure 310 exhibits a buffering effect against the external force PW applied from the outside of the fiber structure 310 toward the bottom surface 311, attenuates the external force PW, and protects the object accommodated in the internal structure 320. It has the effect of

In this example, the bottom surface 311 corresponds to the outer surface to which the external force PW is applied. The slope members 331, 332, 333, and 334 indirectly receive the external force PW via the bottom surface 311, and exhibit a buffering effect against the external force PW.

In the cross-sectional view of FIG. 10, it is assumed that an external force PW is applied in the normal direction of the bottom surface 311. When the angle θ1 of the direction of the external force PW with respect to the fiber orientation direction DS of the slope material 331 is within 45 degrees, the slope material 331 exhibits a buffering effect and absorbs the external force as explained using the test piece 220 as an example. Attenuates PW. Note that even if the angle θ1 is larger than 45 degrees, the buffering effect by the slope material 331 is exerted, but when |θ1| can protect stored items.
Similarly, the slope material 333 exhibits an excellent buffering effect when the angle θ2 of the direction of the external force PW with respect to the fiber orientation direction DS of the slope material 333 is within 45 degrees, and when |θ2|≦45 degrees. exerts force to attenuate external force PW.

The fiber structure 300 has a structure in which a sheet S is used on the outer surface to which the external force PW is directly or indirectly applied. On the other hand, the fiber structure 310 has a structure in which the sheet S is used as an internal structure to which the external force PW is indirectly applied. In any of these cases, the sheet S exerts a cushioning effect and can protect the stored items. In particular, when the fiber orientation direction DS of the sheet S is within 45 degrees with respect to the direction of the external force PW, a good buffering effect is exhibited.

FIG. 11 is a perspective view showing a fibrous structure 350 as yet another configuration example of a fibrous structure using the sheet S. In detail, a cylindrical body 401 as an example of processing the sheet S and a fiber structure 350 produced using the cylindrical body 401 are shown.
The cylindrical body 401 is a structure obtained by rolling the sheet S into a cylindrical shape. The cylindrical body 401 may be a cylinder with a circular cross section, an elliptical cross section, or a polygonal cross section. There may be a portion in the cylindrical body 401 where a plurality of sheets S overlap. The fiber orientation direction DS of the cylindrical body 401 is, for example, a direction along the axial direction of the cylindrical body 401, as shown in FIG.

A cylindrical body 401 is arranged inside the fiber structure 350. The fiber structure 350 is a substantially rectangular box having a bottom surface 351, side surfaces 352, 353, 354, 355, and a top surface 356. The cylindrical body 401 is fixed to at least one of the bottom surface 351 and the top surface 356, preferably both.

FIG. 11 illustrates a case where an external force PW is applied from the outside toward the bottom surface 351. In this example, the bottom surface 351 corresponds to the outer surface to which the external force PW is applied. External force PW is indirectly applied to the cylindrical body 401 via the bottom surface 351. Since the fiber orientation direction DS of the cylindrical body 401 is at an angle within 45 degrees from the direction of the external force PW, the cylindrical body 401 exhibits a buffering effect while deforming against the external force PW. Therefore, when an object is housed in the internal space of the cylindrical body 401, the external force PW transmitted to the object can be attenuated and the object can be protected.

Further, in the fiber structure 350, when the side surfaces 352, 353, 354, and 355 are formed of sheets S, each side surface 352, 353, 354, and 355 exerts a buffering effect together with the cylindrical body 401. Therefore, the stored object can be more reliably protected from the external force PW.

[1-6. Examples of components that make up the sheet]
Examples of the material constituting the sheet S include a combination of cellulose fibers contained in the raw material MA and one or more types of additive materials AD.
With this configuration, a crosslinked structure between cellulose fibers is formed by heating during the manufacturing process of the sheet S, and voids between the fiber structures are maintained in the sheet S, and rigidity can be imparted to the fiber structure. Furthermore, the resin component of the additive material AD that did not contribute to the crosslinked structure has the effect of improving the rigidity of the fiber by coating the surface of the fiber.

Further, when an external force PW is applied, the crosslinked structure of the fiber acts as a micro-deformation region, absorbs the impact and energy of the applied external force PW, and releases it as thermal energy to relax it. This has the effect of exhibiting functions such as shock absorption function and noise absorption as internal loss. As mentioned above, by configuring the fiber orientation direction DS to be located in the range of -45 degrees or more and +45 degrees or less with respect to the direction of the external force PW, the crosslinked structure between the fibers is created when exerting stress in response to the energy of the external force PW. energy relaxation will occur more effectively.

Examples of compositions constituting the sheet S include a first composition example, a second composition example, a third composition example, a fourth composition example, and a fifth composition example.

The first composition example includes cellulose fibers derived from raw material MA, a particulate first resin, and a particulate second resin.
In the first composition example, the particulate first resin and second resin maintain thermal meltability even in the sheet S after production. Therefore, as will be described later, when joining a plurality of sheets S, there is an advantage that they can be easily joined by heating.

The second composition example includes cellulose fibers derived from raw material MA, a particulate first resin, and a fibrous second resin. In the second composition example, the effect that the fibrous second resin firmly joins the cellulose fibers can be expected. Furthermore, since the sheet S contains the particulate first resin, the sheet S after manufacturing maintains superior heat use. Therefore, as will be described later, when joining a plurality of sheets S, there is an advantage that they can be easily joined by heating.

The first resin and the second resin are selected from the above-mentioned thermoplastic resins and thermosetting resins, and it is preferable that at least one of them contains a thermoplastic resin.
Either the first resin or the second resin can be a biodegradable resin. In this case, it is possible to provide a sheet S and a fiber structure with a smaller environmental load. Moreover, when either the first resin or the second resin is made of a resin with high water resistance, the other resin can be made of a water-soluble resin. That is, the sheet S having water resistance can be realized using a water-soluble resin.

The third composition example includes cellulose fibers derived from raw material MA, a particulate first resin, and a fibrous third resin. The third resin is selected from the above-mentioned resin materials or polymer materials that form a porous structure when heated. With this configuration, large voids can be secured by the third resin between the cellulose fibers crosslinked by the first resin. Therefore, it is expected that the ability to absorb impact energy will be further improved.

The fourth composition example includes cellulose fibers derived from raw material MA, a first resin and/or a second resin, and inorganic particles. The inorganic particles are selected from, for example, the above-mentioned inorganic fillers such as calcium carbonate and mica.
The fifth composition example includes cellulose fibers derived from raw material MA, a first resin and/or a second resin, and inorganic fibers or high-rigidity fibers. The inorganic fibers or high-stiffness fibers are selected from the above-mentioned rigid fibers and thixotropic fibers.

The inorganic particles of the fourth composition example and the inorganic fibers or high-rigidity fibers of the fifth composition example have the effect of increasing the stress on the sheet S against the energy of the external force PW. Therefore, it is possible to realize a sheet S and a fiber structure with higher cushioning performance.

Furthermore, in the manufacturing process of the sheet S configured according to the first to fifth composition examples, materials other than the additive material AD may be sprinkled in the deposition process for forming the second web W2. In this case, the specific material can be unevenly distributed on the surface of the sheet S. For example, by dispersing a thermoplastic resin that functions as a bonding material, it can be expected to have the effect of increasing the bonding performance when bonding a plurality of sheets S. Further, for example, there is an advantage that the sheet S can be effectively colored by spraying resin or inorganic particles containing a coloring component.

[1-7. Composition of composite sheet]
The above-described sheets S1 and S2 may be used as they are for the fiber structures 300, 310, and 350, but they may also be used as a composite sheet in which a plurality of sheets S1 and S2 are joined together.

FIG. 12 shows composite sheets 411, 412, 413, 414, 415, and 416 as examples using rectangular sheets S11, S12, S13, and S14 obtained by forming sheet S1 or sheet S2 into rectangular shapes. Further, FIG. 13 shows composite sheets 421, 422, 423, 424, 425, and 426 as examples using rectangular sheets S14 and S15 obtained by forming sheet S1 or sheet S2 into rectangular shapes.

Since the sheets S1 and S2 can be easily cut, rectangular sheets S11-S15 having different lengths and widths can be obtained. A composite sheet 411 can be obtained by stacking and joining two of these sheets. Further, composite sheets 412, 413, 414, 415, 416 can be obtained by stacking and joining three or four rectangular sheets S11, S12, S13, and S14. Further, by using the longer rectangular sheet S15, composite sheets 421, 422, 423, 424, 425, and 426 can be obtained.
As described above, methods for joining the rectangular sheets S11-S15 include pressure, a combination of pressure and heating, and examples of heating methods include oven heating, steam heating, microwave heating, and the like.

The composite sheets 411-416 and 421-426 shown in FIGS. 12 and 13 have different fiber orientation directions DS. Therefore, it is possible to exert a buffering effect against external forces PW applied from various directions. That is, these composites 411-416, 421-426 have a plurality of fiber orientation directions DS that form an angle of 90 degrees with each other. Therefore, no matter from which direction the external force PW is applied, the angle of the external force PW is within 45 degrees with respect to any fiber orientation direction DS. Therefore, it can be expected to exhibit a high buffering effect against external forces PW applied from various directions.

The rectangular sheets S16 and S17 shown in FIGS. 14 and 15 have a fiber orientation direction DS that is diagonal to the outer sides of the rectangular sheets S16 and S17. For example, the rectangular sheets S16 and S17 have a fiber orientation direction DS that forms an angle of 45 degrees with respect to the sides of the outer shape.
Composite sheets 431, 432, 435, 436, and 437 constructed using these have a plurality of fiber orientation directions DS that differ by 45 degrees or 90 degrees. Therefore, it exhibits a buffering effect against external force PW from a wide angle.

In this way, when the fiber structures 300, 310, 350 are constructed using a composite sheet in which a plurality of sheets S1 and/or sheets S2 are combined, the fiber structures have a buffering effect against external forces PW from a wide range. can be realized. A fibrous structure constructed using these composite sheets is particularly referred to as a fibrous structure block.

As described above, the fiber structure 300 to which the present invention is applied includes cellulose fibers arranged such that the main fiber orientation direction DS is the first direction, and a crosslinking material that binds the plurality of cellulose fibers to each other. Contains sheet S. The first direction makes an angle of 45 degrees or less with respect to the direction of the external force PW applied to the outer surface of the fiber structure 300 from the outside.
According to this configuration, since the fiber orientation direction DS of the sheet S forms an angle of 45 degrees or less with respect to the external force PW, the sheet S exhibits a buffering effect due to the action of disassociating the fibers included in the sheet S. do. Therefore, when a container for accommodating an object is constructed using the fiber structure to which the present invention is applied, for example, the object can be protected from impact.

The fiber structure 300 includes cellulose fibers arranged such that the main fiber orientation direction DS is a first direction, and a crosslinking material that binds the plurality of cellulose fibers to each other, and has a storage space for storing objects. The first direction makes an angle of 45 degrees or less with respect to the direction of the external force PW applied from the outside of the fiber structure 300 toward the accommodation space.
According to this configuration, since the fiber orientation direction DS of the sheet S forms an angle of 45 degrees or less with respect to the external force PW, the sheet S exhibits a buffering effect due to the action of disassociating the fibers included in the sheet S. do. Therefore, the objects accommodated in the accommodation space can be protected from impact.

Further, the first direction of the fiber orientation direction DS is a direction that makes an angle of 45 degrees or less with respect to the direction of the external force PW that is applied to the outer surface of the fiber structure 300 directly or via an external member. According to this configuration, the fiber structure exhibits a strong buffering effect by deforming in response to the external force PW, so that the impact of the external force PW can be alleviated.

Furthermore, since the fiber structure 300 has a plurality of outer surfaces and the first direction forms an angle of 45 degrees or less with respect to the normal line of any one of the outer surfaces, the fiber structure 300 is It can exhibit a high buffering effect against external force PW.

Further, since the first direction of the fiber structure 300 forms an angle of 45 degrees or less with respect to the normal to the bottom surface 301, which is the largest outer surface among the plurality of outer surfaces, the external force PW applied from the normal direction to the bottom surface 301 is On the other hand, it can exhibit a high buffering effect.

The crosslinked material contained in the sheet S includes a first resin and a second resin made of a material different from the first resin. In this case, due to the properties of the plurality of resins, the fibers included in the sheet S can be strongly bonded to each other, and functions such as water resistance and reduction of environmental load can be provided.

The sheet S may be configured to include a material different from the cellulose fibers and the crosslinked material. In this case, it is possible to color the sheet S, and also to provide the sheet S with functions such as improved bondability and impact resistance.

The fiber structure 300 may be configured to use a composite sheet as a flat plate structure in which cellulose fibers are laminated, and in this configuration, the first direction may be a direction included in the plane of the flat plate structure. good. In this case, a fiber structure 300 having a plurality of fiber orientation directions DS including the first direction can be realized. Therefore, a high buffering effect can be exerted against external forces PW applied from various directions.

[2. Second embodiment]
As a second embodiment to which the present invention is applied, an example will be described in which a fiber structure is formed by molding the sheet S using a mold.
FIG. 16 is a schematic diagram showing processing by the molding section 120. The molding section 120 has an upper mold 121 and a lower mold 122, and forms the fiber structure 500 by sandwiching the sheet S1 or the sheet S2 between the upper mold 121 and the lower mold 122 and applying pressure. The forming section 120 may be configured as a part of the sheet manufacturing apparatus 100 or may be a separate device from the sheet manufacturing apparatus 100.

The molding section 120 may have a configuration in which a plurality of sheets S can be stacked and sandwiched between an upper mold 121 and a lower mold 122. The upper mold 121 and the lower mold 122 may be male and female molds that fit into each other, or may be molds in which a gap is formed between the upper mold 121 and the lower mold 122.

Further, the molding section 120 may be configured to heat the sheet S during or after pressing the sheet S with the upper mold 121 and the lower mold 122. In this case, as a heating method, a method of increasing the temperature of the entire chamber including the molding part 120 using a heater or the like, or a method of incorporating a heater into the upper mold 121 and/or the lower mold 122 can be adopted. Alternatively, a method may be used in which the fibrous structure 500 after pressurization is heated by a heater or microwave heating.

FIG. 17 is a perspective view showing a fiber structure 510 as a specific example of the fiber structure 500.
The fiber structure 510 has a conical convex portion 511 and a flat portion 512 around the conical convex portion 511 . When the fiber structure 510 is used for a packaging material or a storage container for storing an object, the tip of the convex portion 511 comes into contact with the object. The fiber structure 510 exhibits a buffering effect against the external force PW applied from the normal direction of the plane portion 512.

FIG. 18 is a cross-sectional view taken along the line RR in FIG.
As shown in FIG. 18, at least one direction of the slope of the convex portion 511 overlaps the fiber orientation direction DS. In this case, it is preferable that the angle θ3 of the slope of the convex portion 511 with respect to the external force PW applied from the normal direction of the flat portion 512 is within 45 degrees. That is, |θ3|≦45°. In this case, when the external force PW is applied to the fiber structure 510, the external force PW acts on the convex portion 511 at an angle of 45 degrees or less. Therefore, the convex portion 511 has the effect of attenuating the external force PW.

The fiber structure 510 may be formed by laminating a plurality of sheets S and processing the stacked sheets in the molding section 120. Further, the inside of the convex portion 511 may be densely packed.

FIG. 19 is a perspective view showing a fiber structure 550 as another example of the fiber structure 500 of the second embodiment.
The fiber structure 550 has a truncated cone-shaped pedestal portion 551 and a flat portion 552 around the convex portion 511 . The top portion 553 of the platform portion 551 is a flat surface. When the fibrous structure 550 is used as a packaging material or a storage container for storing an object, the object is placed on the top portion 553.

The fiber structure 550 exhibits a buffering effect against the external force PW applied from the normal direction of the plane portion 552. For this reason, it is preferable that the fiber orientation direction DS is along the slope forming the platform 551, and that the slope of the platform 551 is within 45 degrees with respect to the normal direction of the flat surface 552.

The table portion 551 has a buffering effect against the external force PW, and since the top portion 553 is flat, it has the effect of stabilizing the stored object in the stored state.
Furthermore, a configuration in which a plurality of pedestals 551 are arranged side by side may also be adopted.

FIG. 20 is a perspective view showing a fiber structure 560 as yet another specific example of the fiber structure 500. The fiber structure 560 has a plurality of pedestals 551 and a flat part 562 around the pedestals 551. The base portion 551 is configured similarly to the fiber structure 550.

The fiber structure 560 is suitable for packaging materials and storage containers for storing heavy objects because it can support objects to be stored using the plurality of bases 551.

The above-described fiber structures 510, 550, and 560 have the same effects as those described in the first embodiment as the fiber structures and fiber structure blocks of the present invention.

[3. Other embodiments]
The above-mentioned embodiments are merely specific modes for carrying out the present invention as described in the claims, and do not limit the present invention. For example, as shown below, the embodiments described below do not limit the present invention. , can be implemented in various embodiments.

For example, the sheet S shown in each of the above embodiments is not limited to having a smooth surface, but may have a rough surface by embossing or scraping. Furthermore, the fiber structures and fiber structure blocks configured using the sheet S are not limited to the fiber structures 300, 310, and 350. That is, the shape having the outer surface is not limited to a rectangular parallelepiped, but may be spherical or polyhedral. Further, the fiber structures 510, 550, and 560 may be formed into a box shape, may be installed inside a rectangular parallelepiped structure such as the fiber structure 300, or may be formed into a spherical shape. The specific shape is not limited.
Of course, other detailed configurations can also be changed as desired.

DESCRIPTION OF SYMBOLS 100... Sheet manufacturing apparatus, 120... Molding part, 121... Upper mold, 122... Lower mold, 210, 220, 230... Test piece, 300, 310, 350... Fibrous structure (fibrous structure block), 301... Bottom surface, 302, 303, 304, 305... Side surface, 306... Top surface, 311... Bottom surface, 312, 313, 314, 315... Side surface, 316... Top surface, 320... Internal structure (housing space), 321... Bottom surface, 322, 323, 324, 325...Side surface, 326...Top surface, 331, 332, 333, 334...Slope material, 351...Bottom surface, 352, 353, 354, 355...Side surface, 356...Top surface, 401...Cylindrical body, 411, 412, 413 , 414, 415, 416... Composite sheet, 421, 422, 423, 424, 425, 426... Composite sheet, 431, 432, 435, 436, 437... Composite sheet, 500, 510, 550, 560... Fibrous structure ( Fiber structure block), 511...Convex part, 512...Plane part, 551...Base part, 552...Plane part, 553...Top part, 562...Plane part, AD...Additional material (crosslinked material), DF...Orientation direction, DS , DS1, DS2, DS3, DS4...fiber orientation direction, MA...raw material, PW...external force, S, S1, S2...sheet.

Claims (8)

A fiber structure,
comprising cellulose fibers arranged such that the main fiber orientation direction is a first direction, and a crosslinking material that binds the plurality of cellulose fibers to each other,
The crosslinked material includes a first resin;
a second resin having a glass transition temperature different from the first resin;
A fibrous structure in which the first direction forms an angle of 45 degrees or less with respect to a direction of an external force applied to the outer surface of the fibrous structure from the outside. A fiber structure,
comprising cellulose fibers arranged such that the main fiber orientation direction is a first direction, and a crosslinking material that binds the plurality of cellulose fibers to each other,
The crosslinked material includes a first resin;
a second resin having a glass transition temperature different from the first resin;
It has a storage space for storing things to be stored,
A fibrous structure in which the first direction forms an angle of 45 degrees or less with respect to a direction of an external force applied from the outside of the fibrous structure toward the accommodation space. The fiber structure according to claim 1 or 2, wherein the first direction is a direction forming an angle of 45 degrees or less with respect to the direction of an external force applied directly to the outer surface of the fiber structure or via an external member. body. The fibrous structure according to claim 1, having a plurality of said outer surfaces, and wherein said first direction makes an angle of 45 degrees or less with respect to a normal to any one of said outer surfaces. The fibrous structure according to claim 4, wherein the first direction makes an angle of 45 degrees or less with respect to a normal to the largest outer surface among the plurality of outer surfaces. The fibrous structure according to any one of claims 1 to 5 , comprising a material different from the cellulose fibers and the crosslinked material. The fiber structure according to any one of claims 1 to 6 , which is composed of a flat plate structure in which the cellulose fibers are laminated, and the first direction is a direction included in a surface of the flat plate structure. It is constructed by combining a plurality of fiber structures including cellulose fibers arranged such that the main fiber orientation direction is a first direction, and a crosslinking material that binds the plurality of cellulose fibers to each other,
The crosslinked material includes a first resin;
a second resin having a glass transition temperature different from the first resin;
It has a storage space for storing things to be stored,
A fibrous structure block, wherein the fibrous structures are arranged so that the first direction forms an angle of 45 degrees or less with respect to a direction of an external force applied from the outside toward the accommodation space.

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