Natural fiber molded body and method for producing the same

Abstract

The present invention provides a novel natural fiber molded body and a method for manufacturing the same. 【Solution means】 The method for manufacturing a natural fiber molded body of the present invention includes obtaining a slurry containing natural fibers and a liquid medium, and removing the liquid by freeze-drying the slurry. Further, the natural fiber molded body of the present invention has a surface in a non-woven fabric form, a density of 0.50 g / cm 3 as follows, and a thickness of 5 mm or more.

Description

Technical Field

[0001] The present invention relates to a natural fiber molded body and a method for manufacturing the same.

Background Art

[0002] In order to maintain a sustainable global environment, restrictions on the use of petroleum-derived plastic products are being advanced worldwide. For example, in Europe, the use of expanded polystyrene is prohibited in packaging cushioning materials and the like.

[0003] Therefore, in recent years, molded bodies derived from natural fibers have attracted attention. For example, such natural fiber molded bodies include pulp molds, cellulose sponges, and the like.

[0004] Pulp molds are used for cushioning materials, packaging containers, and the like. Pulp molds are usually manufactured by pouring a pulp slurry into a mold, sucking and dehydrating it, and then drying it. Cellulose sponges are used for kitchen sponges and the like. Cellulose sponges are usually manufactured by adding a foaming agent to a viscose slurry, pouring this into a mold, foaming it, and heating it.

[0005] In addition, as cellulose-derived molded bodies, molded bodies as described in Patent Documents 1 to 3 are also known.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention provides a novel natural fiber molded body and a method for manufacturing the same.

Means for Solving the Problems

[0008] The present invention has the following aspects:

[0009] 《Aspect 1》 Obtaining a slurry containing natural fibers and a liquid medium, and Removing the liquid by freeze-drying the slurry A method for manufacturing a natural fiber molded body including the above. 《Aspect 2》 The method for manufacturing a natural fiber molded body according to Aspect 1, wherein the slurry contains a binder. 《Aspect 3》 The method for manufacturing a natural fiber molded body according to Aspect 2, wherein the liquid medium is an aqueous medium and the binder is a hydrophilic binder. 《Aspect 4》 The method for manufacturing a natural fiber molded body according to Aspect 1, wherein the natural fiber has water dispersibility. 《Aspect 5》 The method for manufacturing a natural fiber molded body according to Aspect 1, wherein the freeness value of the natural fiber measured in accordance with JIS-P-8121-2:2012 is 400 mL or less. 《Aspect 6》 The method for manufacturing a natural fiber molded body according to Aspect 1, wherein the natural fiber is pulp fiber. 《Aspect 7》 A natural fiber molded body having a non-woven fabric-like surface, a density of 0.50 g / cm 3 or less, and a thickness of 5 mm or more. 《Aspect 8》 A natural fiber molded body according to Aspect 7, having a density of 0.10 g / cm 3 or less and a thickness of more than 10 mm. 《Aspect 9》 A natural fiber molded body according to Aspect 7, wherein the content of natural fiber is 50% by mass or more. 《Aspect 10》 The natural fiber is the natural fiber molded body according to Aspect 7, which has water dispersibility. 《Aspect 11》 The natural fiber is the natural fiber molded body according to Aspect 7, which is pulp fiber.

Advantages of the Invention

[0010] According to the present invention, a novel natural fiber molded body and a method for manufacturing the same can be provided.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0012] The present invention will be specifically described by taking the following embodiments as examples, but the present invention is not limited thereto. When there is no particularly detailed mention of the configuration of each embodiment, those skilled in the art can use well-known configurations for these.

[0013] 《Method for Manufacturing Natural Fiber Molded Body》 The method for manufacturing a natural fiber molded body includes obtaining a slurry containing natural fibers and a liquid, and removing the liquid by freeze-drying the slurry.

[0014] The inventor has found that by freeze-drying a slurry containing natural fibers, a novel natural fiber molded body that is thick and lightweight can be obtained. Such a molded body can not only provide biodegradability by natural fibers, but also be easily recycled by removing natural fibers from the molded body, which is extremely effective in constructing a sustainable society.

[0015] The natural fibers used in this method are not particularly limited as long as they are fibers of natural origin, but natural fibers having biodegradability can be particularly used. For example, the natural fibers can include vegetable fibers and animal fibers. Examples of the vegetable fibers can include cellulose-based fibers such as cotton, hemp, and pulp, and examples of the animal fibers can include protein fibers such as wool, silk, mohair, and cashmere. In addition to the natural cellulose-based fibers as described above, regenerated cellulose-based fibers such as viscose rayon and cupra can also be used as the cellulose-based fibers.

[0016] Among these, in particular, fibers having water dispersibility can be mentioned. By using fibers having water dispersibility, the produced molded body can be dispersed in an aqueous medium to make the produced molded body into a slurry. Since the produced molded body contains natural fibers, in one embodiment, the method for producing a natural fiber molded body includes a method for regenerating the natural fiber molded body.

[0017] In this specification, "fibers having water dispersibility" refers to the property that the fibers are dispersed in a dissolved state when immersed in water. For example, when a woven or non-woven fabric made of such fibers is immersed in water to such an extent that it cannot be reused as clothing by a single washing in a normal washing machine, the fibers are dispersed. Fibers having water dispersibility do not include cotton, hemp, wool, silk, mohair, cashmere, viscose rayon, cupra, etc., but include pulp fibers. Such pulp fibers can be obtained by beating pulp and have a relatively short fiber length.

[0018] The average fiber length of the fibers having water dispersibility may be, for example, 10 mm or less, 5.0 mm or less, 3.0 mm or less, or 2.0 mm or less, and may also be 0.3 mm or more, 0.5 mm or more, 1.0 mm or more, or 2.0 mm or more. The average fiber length of the fibers is determined by observing 100 or more fibers with a microscope.

[0019] The natural fibers contained in the slurry may be 1% by mass or more, 3% by mass or more, 5% by mass or more, or 10% by mass or more of the whole slurry, and may be 30% by mass or less, 20% by mass or less, 10% by mass or less, or 8% by mass or less. In particular, when using fibers with water dispersibility, within such a range, it is easy to produce a homogeneous slurry.

[0020] The water dispersibility can be quantitatively evaluated by the freeness value of the fibers measured in accordance with JIS P 8121-2:2012. The freeness value of the natural fibers may be, for example, 500 mL or less, 400 mL or less, 350 mL or less, 300 mL or less, or 250 mL or less, and may be 50 mL or more, 100 mL or more, 150 mL or more, or 200 mL or more.

[0021] As the liquid medium used to obtain the slurry, a liquid medium that can uniformly disperse the natural fibers and is easily removed by freeze-drying later is preferred. The type of the liquid medium is not particularly limited as long as it can uniformly disperse the natural fibers and is easily removed by freeze-drying, and examples include an aqueous medium and an organic solvent-based medium. Among them, it is particularly preferable to use an aqueous medium.

[0022] Examples of the aqueous medium include water, a solvent miscible with water, and a mixture thereof. Examples of the solvent miscible with water include alcohol, dimethylformamide, tetrahydrofuran, cellosolves, lower ketones, or esters. Examples of the alcohol include methanol, isopropanol, or ethylene glycol. Examples of the lower ketones include acetone or methyl ethyl ketone. Examples of the esters include ethyl acetate. These may be used alone or in combination of two or more. Among these, water, alcohol, or a mixture thereof is preferred, and in particular, water and tert-butanol are preferred because freeze-drying is easy.

[0023] The slurry can contain a binder. When manufacturing by binding natural fibers using a binder, toughness can be imparted to the natural fiber molded body. For example, cellulose sponge imparts toughness by incorporating reinforcing fibers such as cotton, but in this embodiment, toughness can be imparted to the natural fiber molded body without incorporating reinforcing fibers. This is presumably because when the liquid is gradually removed during freeze-drying by containing a binder, the binder existing between the natural fibers becomes a knot point. When not using a binder and reinforcing fibers, the natural fiber molded body may exhibit brittleness, and such natural fiber molded bodies may have limited applications.

[0024] Such a binder is not particularly limited as long as it can be dissolved or substantially uniformly dispersed in the liquid medium to be used. For example, as the binder, plant binders such as methyl cellulose, cellulose fiber, cellulose nanofiber, starch, nori seaweed paste, guar gum, karaya gum, and seaweed paste such as tororo aoai; structural proteins such as keratin, fibroin, and collagen; water-soluble polymers such as polyvinyl alcohol, polyacrylamide, and polyethylene glycol; polymer resins (synthetic resin binders) such as modified resin binders obtained by modifying mainly resins used as binders, such as acrylic resin emulsion, vinyl acetate resin-based, latex, SBR (styrene-butadiene-latex) resin, vinyl chloride resin, acrylic-styrene resin-based, acrylic-silicone resin-based, ethylene-vinyl acetate resin-based; inorganic binders such as gypsum, cement, lime, and water glass, and derivatives thereof, etc. are mentioned. The above binders may be used alone or in combination of two or more.

[0025] When using an aqueous medium in the slurry, a hydrophilic binder can be used as the binder. Examples of such hydrophilic binders include the above-mentioned vegetable binders, structural proteins, water-soluble polymers, and the like. Such hydrophilic binders are advantageous because they can form hydrogen bonds with cellulose-based fibers when using cellulose-based fibers as natural fibers, and it is particularly advantageous to use cellulose nanofibers.

[0026] The addition amount of the binder may be 0.1 part by mass or more, 0.5 part by mass or more, 1 part by mass or more, or 3 part by mass or more, and may be 20 parts by mass or less, 10 parts by mass or less, 8 parts by mass or less, or 5 parts by mass or less with respect to 100 parts by mass of the natural fiber.

[0027] Various functions can be imparted to the natural fiber molded body by mixing various additives into the slurry. For example, a coloring pigment can be mixed into the slurry to color the natural fiber molded body; reinforcing fibers can be mixed to enhance mechanical properties; boric acid can be mixed to impart antifungal and insect-proof properties; inorganic fibers such as glass fibers can be mixed to impart flame retardancy; and activated carbon or the like can be mixed to impart deodorizing performance. These additives can be supported in the gaps of the natural fibers in the non-woven three-dimensional structure of the natural fibers after freeze-drying.

[0028] For example, when the additive is contained in the slurry, the content of the additive may be 0.1 part by mass or more, 1 part by mass or more, 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, 100 parts by mass or more, or 200 parts by mass or more, and may be 500 parts by mass or less, 300 parts by mass or less, 200 parts by mass or less, 100 parts by mass or less, 50 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, or 4 parts by mass or less with respect to 100 parts by mass of the natural fiber.

[0029] When reinforcing fibers are contained in the slurry, the content of the additive may be 0.1 part by mass or more, 0.5 part by mass or more, 1 part by mass or more, or 3 part by mass or more, and may be 20 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, or 4 parts by mass or less, based on 100 parts by mass of the natural fibers. The reinforcing fibers can be specified as fibers having a long fiber length. For example, the average fiber length may be 10 mm or more, 15 mm or more, 20 mm or more, or 30 mm or more.

[0030] By freeze-drying in a state where other structures are surrounded by the slurry, other structures can be incorporated into the interior of the molded body. For example, by putting a reinforcing material such as a net-like or rod-like material into the slurry and freeze-drying it, a molded body in which the reinforcing material is incorporated can be obtained. In such an embodiment, it is preferable to select natural fibers having a short fiber length.

[0031] The solid content contained in the slurry may be 1% by mass or more, 3% by mass or more, 5% by mass or more, or 10% by mass or more of the entire slurry, and may be 50% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less.

[0032] This manufacturing method can include putting the above-described slurry into a mold or a container. Then, by freeze-drying the mold or the container together, the liquid of the slurry can be removed by sublimation.

[0033] The depth of the slurry placed in the mold or the container substantially becomes the thickness of the molded body. The depth of the slurry may be, for example, 3 mm or more, 5 mm or more, 10 mm or more, 20 mm or more, or 30 mm or more, and may be 500 mm or less, 300 mm or less, 100 mm or less, 80 mm or less, or 50 mm or less. Within such a range, a thick molded body can be obtained, and the liquid can be removed relatively easily during freeze-drying.

[0034] By injecting the slurry in a state where a sheet is laid on the mold or the container and freeze-drying it, a molded body with the sheet laminated can be obtained.

[0035] The lyophilization performed in this manufacturing method can be carried out by a generally known method. Lyophilization is a method of rapidly freezing at a temperature below the freezing point, reducing the pressure below the vapor pressure of the frozen product to sublime and remove the liquid, and drying the substance. For example, when the liquid is an aqueous medium, the slurry can be rapidly frozen in an environment of -30°C or lower, and the aqueous medium can be removed by reducing the pressure.

[0036] 《Natural Fiber Formed Body》 The natural fiber formed body is not limited by the manufacturing method, but can be manufactured by the manufacturing method of the natural fiber formed body as described above. For each component of the natural fiber formed body, reference can be made to each component described in the manufacturing method of the natural fiber formed body above. Also, for each component of the manufacturing method of the natural fiber formed body above, reference can be made to each component described with respect to the natural fiber formed body.

[0037] The natural fiber formed body has a non-woven fabric-like surface and a density of 0.50 g / cm 3 or less and a thickness of 5 mm or more.

[0038] The density of the natural fiber formed body is 0.01 g / cm 3 or more, 0.02 g / cm 3 or more, 0.05 g / cm 3 or more, or 0.10 g / cm 3 or more, and may be 0.50 g / cm 3 or less, 0.30 g / cm 3 or less, 0.20 g / cm 3 or less, or 0.10 g / cm 3 or less.

[0039] The thickness of the natural fiber formed body may be 3 mm or more, 5 mm or more, 10 mm or more, 20 mm or more, or 30 mm or more, and may be 500 mm or less, 300 mm or less, 100 mm or less, 80 mm or less, or 50 mm or less.

[0040] The present inventors have found that, by the manufacturing method as described above, it is possible to provide a novel natural fiber molded article that is very light and thick. For example, in the case of a pulp mold, if it is desired to increase the thickness, it is necessary to laminate and mold, and the specific gravity increases. A cellulose sponge can increase the thickness and reduce the specific gravity, but the surface does not become non-woven fabric-like.

[0041] In addition, the natural fiber molded article is a porous body having a non-woven fabric-like surface and can have elasticity like expanded polystyrene, whereas a cellulose sponge becomes a sponge-like foam and cannot have elasticity like expanded polystyrene. Note that non-woven fabric-like refers to a state like the surface of a non-woven fabric, and the surface of a pulp mold is also non-woven fabric-like.

[0042] The natural fiber molded article can contain natural fibers as described above. However, when the molded article is manufactured using natural fibers having water dispersibility such as pulp fibers, etc., it can be easily recycled simply by immersing the molded article in water. That is, this molded article can be easily returned to a slurry just by immersing it in water. There has been no conventional natural fiber molded article that is very light, thick, has elasticity like expanded polystyrene, is easy to recycle, and is biodegradable, which is extremely advantageous. Moreover, such a natural fiber molded article can be manufactured at extremely low cost. Therefore, such a natural fiber molded article has the potential to replace molded articles of petroleum-derived products such as expanded polystyrene and foamed polyurethane.

[0043] Since the natural fiber molded article can be a three-dimensional porous body having a non-woven fabric-like shape while having elasticity like expanded polystyrene, unlike expanded polystyrene, it can have air permeability and moisture permeability. Further, when the natural fiber molded article is manufactured using cellulose-based fibers, it can also have deodorizing properties and hygroscopic properties, which is extremely advantageous.

[0044] The natural fiber molded body may have an LC value in the compression characteristic test according to the KES method of 0.5 or more, 0.6 or more, 0.7 or more, or 0.8 or more, and may also be 1.2 or less, 1.1 or less, 1.0 or less, or 0.9 or less. Also, the natural fiber molded body has a WC value (gf·cm / cm 2 ) in the compression characteristic test according to the KES method that may be 0.5 or more, 0.8 or more, 1.0 or more, or 1.5 or more, and may also be 3.0 or less, 2.5 or less, 2.0 or less, or 1.6 or less. Further, the natural fiber molded body may have an RC value (%) in the compression characteristic test according to the KES method of 30 or more, 35 or more, 40 or more, or 45 or more, and may also be 70 or less, 60 or less, 50 or less, or 45 or less. Here, the measurement conditions are that the pressurized area is 1 cm 2 , the maximum load is 50 gf / cm 2 , and the compression speed is 20 μ / sec.

[0045] The natural fiber molded body can contain 25% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more of natural fibers, and may be substantially entirely composed of natural fibers, or may contain natural fibers at 99% by mass or less, 98% by mass or less, 95% by mass or less, 90% by mass or less, or 90% by mass or less.

[0046] Also, the natural fiber molded body can contain a substance derived from the binder as described above in the amount as described above. Thereby, the natural fiber molded body can have, at at least a part thereof, a binding point between fibers derived from the binder, and the toughness of the entire molded body can be enhanced.

[0047] Furthermore, the natural fiber molded body can contain various additives as described above in the amount as described above.

[0048] The natural fiber molded body can be used as it is for various applications, and can also be manufactured using the above-described additives to impart various functions, so that it can be used for more various applications. The natural fiber molded body can be used, for example, as a cushioning material, for packaging, as a filling material, as various containers or parts of containers, as a heat insulating material and a sound insulating material for buildings or vehicles, etc.

[0049] The present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereby.

Examples

[0050] Experiment 1: Natural fiber molded body essentially composed of pulp fibers 〈Manufacturing example〉 The pulp sheet was disintegrated with a beater to obtain pulp fibers. 60 grams of these pulp fibers and 2.4 grams of cellulose nanofibers (4.0 mass% with respect to the weight of the final molded body) as a binder were added to 1 liter of water and mixed well to obtain a slurry. This slurry was put into a container and spread so as to have a uniform thickness. The slurry in that state is shown in Fig. 1.

[0051] This was rapidly frozen to -30°C together with the container, then put into a freeze dryer, and the temperature was gradually raised from -30°C in a vacuum reduced pressure state to digest and dry the moisture. The natural fiber molded body thus obtained was taken out of the container. The obtained natural fiber molded body is shown in Fig. 2.

[0052] The natural fiber molded body thus obtained had a three-dimensional porous body with a non-woven fabric-like surface and had elasticity like expanded polystyrene. The density of this molded body was about 0.06 g / cm 3 and the thickness was about 1.5 cm.

[0053] Similarly, a natural fiber molded body of Example 1 was produced without using a binder. Also, natural fiber molded bodies of Examples 2 and 3 were produced using hydrolyzed keratin (EF) as a binder in variable amounts. Further, natural fiber molded bodies of Examples 4 to 7 were produced using cellulose nanofiber (CNF) as a binder in variable amounts. As a reference example, a pulp sheet having the same basis weight as these molded bodies was also prepared.

[0054] 〈Evaluation〉 Regarding the following physical properties, evaluation was carried out by commissioning to Unitika Garmentec Co., Ltd. (Research Laboratory Business Headquarters).

[0055] For each example, a compression characteristic test according to the KES method was performed. The measurement conditions were that the pressurized area was 1 cm 2 and the maximum load was 50 gf / cm 2 and the compression speed was 20 μ / sec.

[0056] For Example 3 and the reference example, deodorizing property evaluation of ammonia gas was carried out by the detector tube method.

[0057] For Example 1 and 7 and the reference example, hygroscopicity evaluation was carried out under the conditions of 20 °C and 65% relative humidity and 30 °C and 90% relative humidity.

[0058] For Example 2 and 7 and the reference example, heat retention evaluation was carried out using a Thermo Labo II type tester by the dry contact method under the conditions of 20 °C, 65% relative humidity, and a blank heat consumption of 11.6 W / m 2 ·°C.

[0059] For Example 1 and 4 and the reference example, moisture permeability evaluation was carried out in accordance with JIS-L1099:2012.

[0060] 〈Results〉 The results are shown in the following table:

[0061]

Table 1

[0062] The LC (Linearity of Compression) of the compression property indicates the linearity of the compression property and represents how linear the relationship between the compression stress and the compression deformation is. The closer the LC is to 1, the more linearly the compression progresses. When the numerical value of LC is large, it can be said that it becomes hard during the initial compression. When a binder is added, the overall LC increases, indicating that it has become harder.

[0063] The WC (Work of Compression) of the compression property indicates the amount of work required for compression. In the example where 2% of protein fiber was used as the binder, the surface was hairy and a soft layer was formed on the surface. Even when the amount of cellulose nanofiber was large, a soft layer like a thin film was formed on the surface. To measure this surface layer, a large value was obtained. The measured value of WC by the KES method tended to be unstable.

[0064] The RC (Recovery from Compression) of the compression property indicates the recovery rate from compression. The higher the value, the easier it is to return to the original shape. The molded body of Example 6 had a higher resilience.

[0065] Although there was no significant difference in the compression properties in Example 1, it had a brittle property without toughness.

[0066] Looking at the test results of the deodorizing property, it was found that in Example 3, the deodorizing property was significantly improved compared to the pulp sheet with the same basis weight. In the deodorizing test, 70% was a sufficient result. Since the result of Example 3 reached the measurement limit, it became a very high value.

[0067] It was found that the water absorption is higher compared to pulp sheets of the same basis weight. This indicates that these molded articles have humidity control properties. Furthermore, it was found that this molded article also has very high heat retention and moisture permeability. These results are considered to be due to the fact that this molded article has a very low specific gravity compared to the pulp sheet and occupies most of the volume.

[0068] From these results, it was suggested that the molded article of the present case is particularly useful as an interior material for housing, vehicles, etc.

[0069] Experiment 2: Natural fiber molded articles containing various additives 〈Non-combustible material〉 A molded article was obtained in the same manner as in the above production example, except that 150 grams of glass fiber was added to produce a slurry. When a flame retardancy test was conducted on the obtained molded article, a passing result was obtained.

[0070] Note that the obtained molded article was heavy and hard because the amount of glass fiber was large. In the case of ordinary wallpaper, flame retardancy can be obtained even with about 15% by mass of glass fiber. Therefore, it is considered that if the addition amount of glass fiber is 30% by mass or more based on 100 parts by mass of natural fiber, the flame retardancy test of the molded article can pass.

[0071] 〈Coloring pigment〉 A molded article was obtained in the same manner as in the above production example, except that 4 grams of a blue coloring pigment (DIC Corporation, FASTOGEN (trademark) BLUE AR-7EF PB15) was added to produce a slurry. The obtained molded article became light blue. Note that in order to make it a dark color, a measure of pre-dyeing the pulp with a cotton reactive dye can be considered.

[0072] 〈Laminated molded article〉 A molded article was obtained in the same manner as in the above production example, except that hydrolyzed keratin was used as a binder and the slurry was put in after placing silk fabric in the container. By manufacturing in this way, a laminated molded article having the design property of silk fabric on the surface was obtained.

[0073] In addition, when the silk fabric was washed with a small amount of surfactant to enhance its affinity with water and then used, the adhesiveness between the silk fabric and the molded body could be further enhanced.

[0074] <Reinforcing material> After putting the slurry into the container and inserting chopsticks as a reinforcing material and manufacturing in the same manner as in the production example, a molded body reinforced with chopsticks could be obtained.

Claims

1. Obtaining a slurry comprising natural fibers, a binder and a liquid medium; and removing said liquid by freeze-drying said slurry; A method for producing a natural fiber molding comprising: The binder comprises cellulose nanofibers or structural proteins, and The method for producing a natural fiber molding, wherein the natural fiber molding is a cushioning material, a packaging material, a filler, various containers or parts of containers, interior materials for buildings or vehicles, heat insulating materials or sound insulating materials, or deodorizing moldings, and has a density of less than 0.10 g / cm 3 .

2. The method for producing a natural fiber molding according to claim 1 , wherein the slurry contains cellulose nanofibers.

3. The method for producing a natural fiber molding according to claim 2 , wherein the liquid medium is an aqueous medium.

4. The method for producing a natural fiber molding according to claim 1 , wherein the natural fibers have water dispersibility.

5. The method for producing a natural fiber molding according to claim 1, wherein the natural fiber has a freeness value of 400 mL or less as measured in accordance with JIS-P-8121-2:2012.

6. The method for producing a natural fiber molding according to claim 1 , wherein the natural fibers are pulp fibers.

7. The surface is nonwoven and the density is 0.10 g / cm ３ A natural fiber molding containing natural fibers and having a length of less than 1 mm and a thickness of 5 mm or more, wherein the natural fiber molding has binding points between the fibers that are derived from cellulose nanofibers or structural proteins, and is a cushioning material, packaging material, filler, various containers or parts of containers, interior materials for buildings or vehicles, heat insulation material or sound insulation material, or deodorizing moldings.

8. A natural fiber molding as described in claim 7 having a thickness of more than 10 mm.

9. The natural fiber molding according to claim 7 , wherein the content of the natural fibers is 50% by mass or more.

10. The natural fiber molding according to claim 7 , wherein the natural fibers have water dispersibility.

11. The natural fiber molding according to claim 7 , wherein the natural fibers are pulp fibers.

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