Patent Publication Number: US-2021164162-A1

Title: Method and apparatus for manufacturing fiber molded article, and binding raw material and method for manufacturing the same

Description:
The present application is based on, and claims priority from JP Application Serial Number 2019-216286, filed Nov. 29, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a method and an apparatus for manufacturing a fiber molded article, and a binding raw material and a method for manufacturing the same. 
     2. Related Art 
     As a method for manufacturing a fiber molded article, such as paper, a so-called dry method in which no water or substantially no water is used has been expected. For example, JP-A-2015-168255 has disclosed an apparatus for manufacturing a fiber molded article. The apparatus described above includes a mixing portion mixing first fibers and a powder at least containing natural fibers and a resin integrated therewith and a binding portion binding the first fibers and the powder, and the powder described above has a volume average particle diameter of 3 to 50 μm. 
     According to the technique disclosed in JP-A-2015-168255, after a defibrated cotton obtained by defibrating old paper is mixed with a binding raw material formed from a thermoplastic resin, heat and pressure are applied thereto to manufacture a regenerated sheet. However, as the thermoplastic resin which forms a binding raw material, a petroleum-derived resin, such as a polyester, is used. In addition, when a resin other than the petroleum-derived resin is used for a binding raw material, and this binding raw material is applied to a fiber molded article, mechanical strengths, such as a tensile strength and a tear strength, and a paper strength of the fiber molded article may be insufficient in some cases. 
     SUMMARY 
     According to an aspect of the present disclosure, there is provided a method for manufacturing a fiber molded article, the method comprising a step of heating a mixture of defibrated first fibers and a binding raw material in which a thermoplastic plant-derived resin is integrated with natural fibers to bind the first fibers with the binding raw material. 
     In the method for manufacturing a fiber molded article according to the aspect described above, the natural fibers may include cellulose fibers. 
     In the method for manufacturing a fiber molded article according to the aspect described above, the thermoplastic plant-derived resin may be at least one selected from a polylactic acid), a bio-polyamide, a poly(hydroxyalkanoic acid), and an isosorbide-containing resin. 
     In the method for manufacturing a fiber molded article according to the aspect described above, the thermoplastic plant-derived resin and the natural fibers in the binding raw material may be contained at a mass ratio (thermoplastic plant-derived resin/natural fibers) of 1/3 to 4/1. 
     In the method for manufacturing a fiber molded article according to the aspect described above, the natural fibers in the binding raw material may have an average fiber length of 0.8 to 2.0 mm. 
     According to another aspect of the present disclosure, there is provided an apparatus for manufacturing a fiber molded article, the apparatus comprising: a heating portion heating defibrated first fibers and a binding raw material in which a thermoplastic plant-derived resin is integrated with natural fibers to bind the first fibers with the binding raw material. 
     The apparatus for manufacturing a fiber molded article according to the aspect described above may further comprise: a defibrating portion defibrating a raw material containing fibers to obtain the first fibers; and a mixing portion mixing the first fibers and the binding raw material. 
     The apparatus for manufacturing a fiber molded article according to the aspect described above may further comprise: a deposition portion depositing the first fibers and the binding raw material which are mixed in the mixing portion. 
     In the apparatus for manufacturing a fiber molded article according to the aspect described above, the thermoplastic plant-derived resin and the natural fibers in the binding raw material may be contained at a mass ratio (thermoplastic plant-derived resin/natural fibers) of 1/3 to 4/1. 
     The apparatus for manufacturing a fiber molded article according to the aspect described above may further comprise: a pressure application portion pressurizing the first fibers bound with the binding raw material by the heating portion. 
     In the apparatus for manufacturing a fiber molded article according to the aspect described above, the thermoplastic plant-derived resin may be at least one selected from a poly(lactic acid), a bio-polyamide, a poly(hydroxyalkanoic acid), and an isosorbide-containing resin. 
     In the apparatus for manufacturing a fiber molded article according to the aspect described above, the natural fibers in the binding raw material may have an average fiber length of 0.8 to 2.0 mm. 
     According to another aspect of the present disclosure, there is provided a binding raw material comprising a thermoplastic plant-derived resin and natural fibers integrated therewith. 
     According to another aspect of the present disclosure, there is provided a method for manufacturing a binding raw material, the method comprising a step of kneading a thermoplastic plant-derived resin and natural fibers so that the thermoplastic plant-derived resin is integrated with the natural fibers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing an apparatus for manufacturing a fiber molded article according to an embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, several embodiments of the present disclosure will be described. In addition, the following embodiments are described to explain examples of the present disclosure. The present disclosure is not limited to the following embodiments and may also include various modified embodiments without departing from the scope of the present disclosure. In addition, all the structures described below are not always required to be essential constituent elements of the present disclosure. 
     1. Binding Raw Material 
     A binding raw material according to this embodiment is formed such that a thermoplastic plant-derived resin and natural fibers are integrated with each other. The binding raw material may be preferably applied to a method and an apparatus for manufacturing a fiber molded article which will be described later. 
     1.1. Thermoplastic Plant-Derived Resin 
     The thermoplastic plant-derived resin has a thermoplastic property. In addition, a raw material of the thermoplastic plant-derived resin is not derived from petroleum but is derived from plants, bacteria, algae, and the like. 
     The thermoplastic property indicates a property of a substance which is softened by heating, and for example, when thermal physical characteristics thereof are observed, deformation and/or fluidity may be recognized. In addition, the thermoplastic plant-derived resin may be either in an amorphous or a crystalline state. 
     As the thermoplastic plant-derived resin, for example, a poly(lactic acid), a bio-polyamide, a poly(hydroxyalkanoic acid), and an isosorbide-containing resin may be mentioned. Those are resins formed using, as a primary raw material, lactic acid, amino acids, hydroxy acids, and isosorbide, respectively. A raw material of the thermoplastic plant-derived resin may be fully derived from plants or may be derived from plants by 60.0% or more, preferably 80.0% or more, more preferably 90% or more, and further preferably 95.0% or more of the raw material. 
     Since the binding raw material according to this embodiment contains the thermoplastic plant-derived resin, in a fiber molded article using the above binding raw material, the use amount of a petroleum-derived material can be reduced, and hence, environmental load can be reduced. Furthermore, since the thermoplastic plant-derived resin has a thermoplastic property, when the fiber molded article is further defibrated and is used as a raw material, recycling can also be easily performed. 
     The thermoplastic plant-derived resin may be confirmed as a plant-derived resin, for example, by investigating whether or not a constituent unit of the resin is formed by biosynthesis. That is, the plant-derived resin can be determined by using the fact that an optical isomer of a monomer unit obtained by chemical synthesis is significantly different from that obtained by biosynthesis. For example, in the case of a poly(lactic acid), when a chemically synthesized lactic acid is used as a raw material, the raw material has a racemic form, and on the other hand, when a plant-derived lactic acid is used as a raw material, an existence rate of an L-form or a D-form is high. Hence, when the monomer unit of a poly(lactic acid) is analyzed by an analytical method having an optical sensitivity, it can be determined whether the raw material of the poly(lactic acid) is obtained by chemical synthesis or is a plant-derived material. 
     For example, since being excellent in affinity to first fibers which will be described later and excellent in binding thereof, as the thermoplastic plant-derived resin, a poly(lactic acid), a bio-polyamide, a poly(hydroxyalkanoic acid), and an isosorbide-containing resin are preferable, and a poly(lactic acid), a poly(hydroxyalkanoic acid), and an isosorbide-containing resin are particularly preferable. As the thermoplastic plant-derived resin, at least two types of resins may also be used in combination. 
     Although the content of the thermoplastic plant-derived resin with respect to the total of the binding raw material is not particularly limited, for example, the content described above is 40 to 98 percent by mass, preferably 50 to 95 percent by mass, and more preferably 70 to 90 percent by mass. 
     Although a glass transition temperatures (Tg) or a melting point (Tm) of the thermoplastic plant-derived resin is not particularly limited, at a temperature at which the natural fibers which will be described below may not be damaged, the thermoplastic plant-derived resin is preferably placed in a rubber state or a fluidized state, and the temperature described above is, for example, 25° C. to 150° C., preferably 30° C. to 120° C., and more preferably 40° C. to 100° C. Tg and Tm of the thermoplastic plant-derived resin can be measured, for example, by a differential scanning calorimetry (DSC) or the like. 
     1.2. Natural Fibers 
     The binding raw material of this embodiment contains the natural fibers. Although the natural fibers are not particularly limited as long as being naturally derived fibers, for example, there may be mentioned fibers formed from a cellulose, a silk, a wool, a cotton, a hemp, a kenaf, a flax, a ramie, a jute, a Manila hemp, a Sisal hemp, a coniferous tree, or a broadleaf tree, and those mentioned above may be used alone or in appropriate combination or may be used as regenerated fibers after refining or the like. In addition, when the fiber molded article is formed into a sheet such as paper, the natural fibers are more preferably cellulose fibers. 
     As a raw material of the natural fibers, for example, although old paper or old cloths may be mentioned, a raw material containing at least one type of fibers thereof may be used. In addition, the fibers may be processed with various surface treatments. In addition, a material of the fibers may be either a pure material or a material containing a plurality of components, such as impurities, additives, and components other than those mentioned above. 
     When the natural fibers are disentangled into fibers independent of each other, an average diameter of the fiber is 1 to 1,000 μm, preferably 2 to 500 μm, and more preferably 3 to 200 μm, the average diameter of the fiber being, when a cross-section thereof is not a circle, a maximum length of the fiber in a direction perpendicular to a longitudinal direction thereof or a diameter (equivalent circle diameter) of a virtual circle which is assumed to have an area equivalent to that of the cross-section. 
     Although an average fiber length of the natural fibers is not particularly limited, as the independent one fiber, the length of the fiber along the longitudinal direction is 1 μm to 5 mm, preferably 2 μm to 3 mm, and more preferably 3 μm to 2 mm. When the binding raw material is used as the raw material of the fiber molded article which will be described later, in order to further improve the mechanical strength of a fiber molded article to be obtained, the average fiber length of the natural fibers in the binding raw material is set to preferably 0.5 to 3.0 mm, more preferably 0.8 to 2.0 mm, and further preferably 0.9 to 1.8 mm. 
     1.3. Characteristics, Structure, and Composition of Binding Raw Material 
     The binding raw material of this embodiment may be configured in the form of powder. When the form of the binding raw material is a powder, a particle diameter (volume-basis average particle diameter) of particles of the binding raw material is, for example, 10.0 mm or less, preferably 5.0 mm or less, and more preferably 1.0 mm or less. In addition, when the binding raw material is used as the raw material of the fiber molded article which will be described later, the particle diameter (volume-basis average particle diameter) of the particles of the binding raw material is preferably 100 μm or less, preferably 50 μm or less, more preferably 30 μm or less, and further preferably 20 μm or less. In the case described above, as the average particle diameter is decreased, the gravity acting on the binding raw material is decreased, and when the fiber molded article which will be described later is formed, the binding raw material is suppressed from being separated between the first fibers due to its own weight. In addition, when the particle diameter of the binding raw material is in the particle range described above, the binding raw material is sufficiently suppressed from being separated between the first fibers, and hence, the first fibers are able to be bound to each other. 
     In addition, although being preferably an approximately spherical shape, the exterior shape of the particle of the binding raw material is not particularly limited, and for example, a disc, a spindle, or an irregular shape may be used. Although the volume average particle diameter as the whole of the particles of the binding raw material may be appropriately determined, for example, the volume average particle diameter and the particle size distribution of the particles of the binding raw material may be adjusted by a classification operation or the like. 
     The volume average particle diameter of the particles of the binding raw material may be calculated by direct observation of the particles using a digital microscope (“VHK-7000” manufactured by Keyence Corporation) and direct measurement of particle diameters by image processing. 
     In the binding raw material of this embodiment, the thermoplastic plant-derived resin described above and the natural fibers are integrated with each other. In this embodiment, the state in which the thermoplastic plant-derived resin and the natural fibers are integrally formed with each other indicates a state in which the thermoplastic plant-derived resin and/or the natural fibers are unlikely to be separated from the particles of the binding raw material. That is, the state in which in the particles of the binding raw material, the thermoplastic plant-derived resin and the natural fibers are integrally formed with each other indicates a state in which the natural fibers are adhered to each other with the thermoplastic plant-derived resin, a state in which the natural fibers are structurally (mechanically) fixed to the thermoplastic plant-derived resin, a state in which the thermoplastic plant-derived resin and the natural fibers are aggregated by an electrostatic force, van der Waals force, or the like, or a state in which the thermoplastic plant-derived resin and the natural fibers are chemically bonded to each other. 
     In addition, the state in which the thermoplastic plant-derived resin and the natural fibers are integrally formed with each other in the particles of the binding raw material may indicate a state in which the natural fibers are enclosed in the thermoplastic plant-derived resin, a state in which the natural fibers are adhered to the thermoplastic plant-derived resin, or a state in which the two states described above are simultaneously present. 
     A mass ratio (thermoplastic plant-derived resin/natural fibers) of the thermoplastic plant-derived resin to the natural fibers in the binding raw material is 1/5 to 10/1, preferably 1/4 to 6/1, and further preferably 1/3 to 4/1. Since the mass ratio is set in the range described above, when the binding raw material is used as a raw material of the fiber molded article, a function to bind the first fibers which will be described later can be further enhanced, and in addition, a function to maintain and improve mechanical strengths, such as a tensile strength and a tear strength, and a paper strength of the fiber molded article can be further enhanced. 
     1.4. Other Components 
     As long as the effects obtained when the thermoplastic plant-derived resin and the natural fibers are contained are not degraded, other components may also be contained in the binding raw material. As the components described above, for example, there may be mentioned a synthetic resin, a colorant, an aggregation suppressor, an ultraviolet absorber, a flame retardant, an antistatic agent, a charge control agent, an organic solvent, a surfactant, a fungicide/antiseptic agent, an antioxidant, and/or an oxygen absorber. Those components each may be added as one component of the binding raw material to the particles thereof. 
     As the synthetic resin, for example, there may be mentioned a polyethylene, a polypropylene, a polyamide, a polyacetal, a poly(ethylene terephthalate), a poly(butylene terephthalate), a poly(ethylene succinate), a poly(butylene succinate), a poly(hydroxybutyric acid), a poly(lactic acid), a poly(phenylene sulfide), a poly(ether ketone), a poly(vinyl chloride), a polystyrene, a poly(methyl (meth)acrylate), an acrylonitrile-butadiene-styrene resin, a polycarbonate, a modified poly(phenylene ether), a poly(ether sulfone), a poly(ether imide), or a poly(amide imide). In addition, the synthetic resin may also be copolymerized or modified, and for example, there may be used a styrene resin, an acrylic resin, a styrene-acrylic resin, an olefinic resin, a vinyl chloride resin, a polyester resin, a polyamide resin, a polyurethane resin, a poly(vinyl alcohol) resin, a vinyl ether resin, an N-vinyl resin, or a styrene-butadiene resin, each of which has amorphous characteristics by copolymerization or modification. 
     When being used as the raw material of the fiber molded article, the binding raw material has a function to bind the first fibers which will be described later. In addition, when being used as the raw material of the fiber molded article, the binding raw material also has a function to maintain and improve the mechanical strengths, such as a tensile strength and a tear strength, and the paper strength of the fiber molded article. In addition, whether the binding raw material as described above is contained in the fiber molded article or not can be confirmed, for example, by an infrared (IR) spectroscopy, a nuclear magnetic resonance (NMR) analysis, a mass spectroscopy (MS), and/or various chromatographic techniques. 
     1.5. Operational Effects 
     When the binding raw material according to this embodiment is applied to a fiber molded article, the mechanical strengths, such as a tensile strength and a tear strength, and the paper strength of the fiber molded article can be sufficiently obtained. 
     In addition, in a related petroleum-derived resin, since its monomer compositions are relatively uniform, secondary crystallization is liable to proceed with time, and the resin itself may unfavorably become brittle in some cases. However, in a thermoplastic plant-derived resin, since its monomer compositions vary to a certain extent, the probability of occurrence of the secondary crystallization is low, and the resin is not likely to become brittle. Hence, when the thermoplastic plant-derived resin is applied to a fiber molded article, the quality, such as the mechanical strengths, can be maintained for a long time. 
     2. Method for Manufacturing Binding Raw Material 
     A method for manufacturing a binding raw material according to this embodiment includes a step of kneading the thermoplastic plant-derived resin and the natural fibers to integrate the thermoplastic plant-derived resin and the natural fibers. 
     The method for manufacturing a binding raw material according to this embodiment includes, for example, a kneading step of melting and kneading the thermoplastic plant-derived resin and the natural fibers to form the binding raw material, a pelletizing step of pelletizing the binding raw material, and a pulverizing step of pulverizing the pelletized binding raw material. 
     In the kneading step, the thermoplastic plant-derived resin and the natural fibers are melted and kneaded. The thermoplastic plant-derived resin and the natural fibers each may be prepared in any form. In the kneading step described above, the contents of the thermoplastic plant-derived resin and the natural fibers with respect to the total mass of the binding raw material may be adjusted. 
     When the thermoplastic plant-derived resin and the natural fibers are melted and kneaded, a binding raw material in which the above two substances are integrated with each other can be obtained. A temperature for melting and kneading may be appropriately set, for example, by adjusting a melting temperature or the like of the thermoplastic plant-derived resin and conditions of an apparatus to be used for the melting and kneading. The binding raw material formed by the melting and kneading may be used as a powdered binding raw material by direct pulverization or a pelletized binding raw material through a pelletizing step performed after extrusion molding. When the binding raw material is formed by the melting and kneading, for example, by the pelletization, the pulverization, and/or combination therebetween, a binding raw material having a predetermined volume average particle diameter can be obtained. 
     The melting and kneading may be performed, for example, using a kneader, a banbury mixer, a single screw extruder, a multi-screw extruder, a twin roll mill, a triple roll mill, a continuous kneader, or a continuous twin roll mill. The pulverization may be performed using a pulverizer, such as a hammer mill, a pin mill, a cutter mill, a pulperizer, a turbo mill, a disc mill, a screw mill, or a jet mill. When those pulverizers are appropriately used in combination, the binding raw material can be obtained in the form of pellets or powder. 
     The pulverization step may be performed in a stepwise manner such that after the binding raw material is first coarsely pulverized to have a particle diameter of approximately 1 mm, fine pulverization is performed to obtain a desired particle diameter. In the case as described above, at each stage, the devices described above by way of example each may be appropriately used. Furthermore, in order to further increase the efficiency of the pulverization of the binding raw material, a freeze pulverizing method may also be used. A powdered binding raw material thus obtained may be used as the binding raw material, and particles having various particle diameters may be contained therein. Hence, if needed, classification may be performed using a known classification device. 
     The volume average particle diameter of the particles of the binding raw material may be calculated such that after the particles are directly observed, for example, with a digital microscope (“VHK-7000” manufactured by Keyence Corporation), the particle diameters are directly measured by image processing. 
     3. Method for Manufacturing Fiber Molded Article 
     In a method for manufacturing a fiber molded article according to this embodiment, while being mixed with each other, defibrated first fibers and the binding raw material described above in which the thermoplastic plant-derived resin and the natural fibers are integrated with each other are heated, and hence, the first fibers are bound to each other with the binding raw material. 
     The fiber molded article according to this embodiment includes the binding raw material described above and the first fibers, and by the binding raw material, the first fibers are bound to each other. The fiber molded article mainly indicates an article formed to have a sheet shape. However, the fiber molded article is not limited to have a sheet shape and may have a board shape, a web shape, or an irregular shape. As a typical example of the fiber molded article according to this specification, paper or a non-woven cloth may be mentioned. The paper includes, for example, a sheet formed using pulp or old paper as a raw material and includes recording paper for writing and printing, wallpaper, wrapping paper, colored paper, drawing paper, Kent paper, and the like. The non-woven cloth has a large thickness and/or a low strength as compared to that of paper and includes a general non-woven cloth, a fiber board, tissue paper, kitchen paper, a cleaner, a filter, a liquid absorber, a sound absorber, a cushioning material, a mat, and the like. 
     The first fibers contained in the fiber molded article according to this embodiment are not particularly limited, and various fiber materials may be used. As the fibers, for example, there may be mentioned natural fibers (animal fibers or plant fibers) and chemical fibers (organic fibers, inorganic fibers, or organic inorganic composite fibers). In more particular, for example, there may be mentioned fibers formed from a cellulose, a silk, a wool, a cotton, a hemp, a kenaf, a flax, a ramie, a jute, a Manila hemp, a Sisal hemp, a coniferous tree, or a broadleaf tree, and those mentioned above may be used alone or in appropriate combination or may be used as regenerated fibers after refining or the like. 
     As a raw material of the first fibers, for example, although old paper and/or an old cloth may be mentioned, the raw material may contain at least one type of fibers obtained therefrom. In addition, a raw material processed by various surface treatments may also be used. In addition, a material of the first fibers may be either a pure material or a material containing a plurality of components, such as impurities, additives, and components other than those mentioned above. 
     When the first fibers are disentangled into independent fibers, an average diameter of the fiber is 1 to 1,000 μm, preferably 2 to 500 μm, and more preferably 3 to 200 μm, the average diameter of the fiber being, when a cross-section thereof is not a circle, a maximum length of the fiber in a direction perpendicular to a longitudinal direction thereof or a diameter (equivalent circle diameter) of a virtual circle which is assumed to have an area equivalent to that of the cross-section. 
     Although the average fiber length of the first fibers is not particularly limited, as the independent one fiber, the length of the fiber along the longitudinal direction thereof is 1 μm to 5 mm, preferably 2 μm to 3 mm, and more preferably 3 μm to 2 mm. 
     The method for manufacturing a fiber molded article according to this embodiment includes a mixing step of mixing the binding raw material and the first fibers described above, a deposition step of depositing the first fibers and the binding raw material mixed therewith to form a deposited material, and a step of binding the fibers with the binding raw material of the deposited material thus deposited. 
     The mixing step may be performed, for example, by mixing the first fibers and the binding raw material in air. The deposition step may be performed by allowing the mixture mixed in the mixing step to fall in air and to deposit on a mesh or the like. The binding step may be performed to melt the binding raw material by heating the deposited material obtained in the deposition step by a heat roller machine or the like. 
     The method for manufacturing a fiber molded article according to this embodiment may further includes, if needed, at least one selected from the group consisting of a cutting step of cutting pulp sheets or old paper used as a raw material in air, a defibrating step of defibrating the raw material into fibers in air, a classification step of classifying from the defibrated material thus defibrated in air, impurities and fibers shortened by the defibration, a sorting step of sorting from the defibrated material in air, long fibers (long filaments) and non-defibrated pieces which are not sufficiently defibrated, a pressure application step of pressurizing at least one of the deposited material and the fiber molded article, a cutting step of cutting the fiber molded article, and a wrapping step of wrapping the fiber molded article. 
     In the fiber molded article, a mixing rate between the first fibers and the binding raw material may be appropriately adjusted in accordance with the strength, the application, and the like of a fiber molded article to be manufactured. When the fiber molded article is used for office applications, such as copy paper, the rate of the binding raw material to the fibers is, for example, 5 to 70 percent by mass. 
     According to the method for manufacturing a fiber molded article of this embodiment, since the binding raw material described above is used, even if the use amount of a petroleum-derived material is reduced, a fiber molded article having sufficient mechanical strengths, such as a tensile strength and a tear strength, and paper strength can be manufactured. In addition, the fiber molded article thus obtained can be easily recycled. 
     4. Apparatus for Manufacturing Fiber Molded Article 
     An apparatus for manufacturing a fiber molded article according to this embodiment includes at least a heating portion which heats the defibrated first fibers described above and the binding raw material in which the thermoplastic plant-derived resin and the natural fibers are integrated with each other so as to bind the first fibers with the binding raw material. 
     One example of the apparatus for manufacturing a fiber molded article according to this embodiment will be described with reference to the drawing.  FIG. 1  is a schematic view showing a fiber molded article manufacturing apparatus  100  according to this embodiment. In the fiber molded article manufacturing apparatus  100 , as the fiber molded article, a sheet S is manufactured such that the defibrated first fibers and the binding raw material in which the thermoplastic plant-derived resin and the natural fibers are integrated with each other are heated so as to bind the first fibers with the binding raw material. 
     As shown in  FIG. 1 , the fiber molded article manufacturing apparatus  100  includes, for example, a supply portion  10 , a coarsely pulverizing portion  12 , a defibrating portion  20 , a sorting portion  40 , a first web forming portion  45 , a rotation body  49 , a mixing portion  50 , a deposition portion  60 , a second web forming portion  70 , a sheet forming portion  80 , and a cutting portion  90 . 
     The supply portion  10  supplies the raw material to the coarsely pulverizing portion  12 . The supply portion  10  is, for example, an automatic feeder to continuously feed the raw material to the coarsely pulverizing portion  12 . The raw material to be supplied by the supply portion  10  is a material, such as waste paper and/or a pulp sheet, containing the first fibers described above. 
     The coarsely pulverizing portion  12  cuts the raw material supplied by the supply portion  10  into small pieces in a gas atmosphere such as in the air. For example, the small pieces each have a several centimeters square shape. In the example shown in the drawing, the coarsely pulverizing portion  12  has coarsely pulverizing blades  14 , and by the coarsely pulverizing blades  14 , the raw material to be charged can be cut. As the coarsely pulverizing portion  12 , for example, a shredder may be used. The raw material cut by the coarsely pulverizing portion  12  is received by a hopper  1  and is then transported to the defibrating portion  20  through a tube  2 . 
     The defibrating portion  20  defibrates the raw material cut by the coarsely pulverizing portion  12 . In this step, the “defibrate” indicates that a raw material in which fibers are bound to each other is disentangled into fibers separated from each other. The defibrating portion  20  also has a function to separate resin particles and substances, such as an ink, a toner, and a blurring inhibitor, which are adhered to the raw material from the fibers. 
     A material passing through the defibrating portion  20  is called a “defibrated material”. The “defibrated material” may contain in some cases, besides disentangled defibrated fibers, resin particles, colorants, such as an ink and a toner, and additives, such as a blurring inhibitor and a paper strength enhancer, which are separated from the fibers when the fibers are disentangled. The disentangled defibrated material is in the form of strings. The disentangled defibrated material may be not entangled with other disentangled fibers, that is, may be independently present or may be entangled with other disentangled defibrated material to form aggregates, that is, may be present in the form of damas. 
     The defibrating portion  20  performs a dry defibration. In addition, a treatment, such as defibration, which is performed not in a liquid but in a gas, such as in the air, is called a dry treatment. As the defibrating portion  20 , for example, an impellor mill is used. The defibrating portion  20  has a function to generate an air stream which sucks the raw material and discharges the defibrated material. Accordingly, by the air stream thus generated as described above, the defibrating portion  20  can perform a defibrating treatment by sucking the raw material from an inlet port  22  together with the air stream and then can transport the defibrated material to a discharge port  24 . The defibrated material passing through the defibrating portion  20  is transported to the sorting portion  40  through a tube  3 . In addition, as an air stream which transports the defibrated material from the defibrating portion  20  to the sorting portion  40 , the air stream generated by the defibrating portion  20  may be used, or an air stream generated by installing an air generation device, such as a blower, may also be used. 
     The sorting portion  40  introduces the defibrated material which is defibrated by the defibrating portion  20  from an inlet port  42  and then sorts the defibrated material by the lengths of the fibers. The sorting portion  40  includes a drum portion  41  and a housing portion  43  receiving the drum portion  41 . As the drum portion  41 , for example, a sieve is used. The drum portion  41  has a net and can sort fibers and/or particles which are smaller than an opening size of this net, that is, a first sorted material passing through the net, and fibers, non-defibrated pieces, and/or damas which are larger than the opening size of the net, that is, a second sorted material not passing through the net. For example, the first sorted material is transported to the mixing portion  50  through a tube  7 . The second sorted material is returned to the defibrating portion  20  from a discharge port  44  through a tube  8 . In particular, the drum portion  41  is a cylindrical sieve rotatably driven by a motor. As the net of the drum portion  41 , for example, there may be used a metal net, an expanded metal formed by expanding a metal plate provided with cut lines, or a punched metal in which holes are formed in a metal plate by a press machine or the like. 
     The first web forming portion  45  transports the first sorted material passing through the sorting portion  40  to the tube  7 . The first web forming portion  45  includes a mesh belt  46 , tension rollers  47 , and a suction mechanism  48 . 
     The suction mechanism  48  can suck the first sorted material which passes through openings of the sorting portion  40  and which is dispersed in air onto the mesh belt  46 . The first sorted material is deposited on the moving mesh belt  46  to form a web V. Basic structures of the mesh belt  46 , the tension rollers  47 , and the suction mechanism  48  are similar to those of a mesh belt  72 , tension rollers  74 , and a suction mechanism  76  of the second web forming portion  70  which will be described later. 
     Since passing through the sorting portion  40  and the first web forming portion  45 , the web V is formed so as to be softly expanded with a large amount of air incorporated therein. The web V deposited on the mesh belt  46  is charged in the tube  7  and is then transported to the mixing portion  50 . 
     The rotation body  49  can cut the web V. In the example shown in the drawing, the rotation body  49  includes a base portion  49   a  and protruding portions  49   b  protruding from the base portion  49   a . The protruding portions  49   b  each have, for example, a plate shape. In the example shown in the drawing, four protruding portions  49   b  are provided with regular intervals. When the base portion  49   a  is rotated in a direction R, the protruding portions  49   b  can be rotated around the base portion  49   a . Since the web V is cut by the rotation body  49 , for example, the change in amount of the defibrated material per unit time to be supplied to the mixing portion  50  can be reduced. 
     The rotation body  49  is provided in the vicinity of the first web forming portion  45 . In the example shown in the drawing, the rotation body  49  is provided in the vicinity of a tension roller  47   a  located downstream in a path of the web V. The rotation body  49  is provided at a position at which the protruding portion  49   b  can be brought into contact with the web V and cannot be brought into contact with the mesh belt  46  on which the web V is deposited. Accordingly, the mesh belt  46  can be suppressed from being abraded by the protruding portions  49   b . The shortest distance between the mesh belt  46  and the protruding portion  49   b  is, for example, 0.05 to 0.5 mm. This is a distance at which the web V can be cut with no damage on the mesh belt  46 . 
     The mixing portion  50  mixes the first sorted material passing through the sorting portion  40  and additives containing the binding raw material described above. The mixing portion  50  includes an additive supply portion  52  supplying the additives, a tube  54  transporting the first sorted material and the additives, and a blower  56 . In the example shown in the drawing, the additives are supplied from the additive supply portion  52  to the tube  54  through a hopper  9 . The tube  54  is coupled to the tube  7 . 
     In the mixing portion  50 , an air stream is generated by the blower  56 , and the first sorted material and the additives can be transported through the tube  54  while being mixed with each other. In addition, a mechanism to mix the first sorted material and the additives is not particularly limited, and for example, a mechanism in which stirring is performed by at least one high speed rotational blade or a mechanism, such as a V-type mixer, which uses rotation of a container may be used. 
     As the additive supply portion  52 , a screw feeder as shown in  FIG. 1  or a disc feeder not shown may be used. The additives to be supplied from the additive supply portion  52  include the binding raw material. When the binding raw material is supplied, the first fibers are not bound to each other. The binding raw material is melted when passing through the sheet forming portion  80 , so that the fibers are bound together. 
     In addition, as the additives to be supplied from the additive supply portion  52 , besides the binding raw material, in accordance with the type of sheet to be manufactured, a colorant which colors the first fibers, an aggregation suppressor which suppresses aggregation of the first fibers and/or the binding raw material, and/or a flame retardant which enables the fibers and the like to be hardly combustible may also be contained. A mixture passing through the mixing portion  50  is transported to the deposition portion  60  through the tube  54 . 
     After the deposition portion  60  introduces the mixture passing through the mixing portion  50  from an inlet port  62 , the entangled defibrated material is disentangled and allowed to fall down while being dispersed in air. Accordingly, the deposition portion  60  is able to uniformly deposit the mixture on the second web forming portion  70 . 
     The deposition portion  60  includes a drum portion  61  and a housing portion  63  receiving the drum portion  61 . As the drum portion  61 , a rotatable cylindrical sieve is used. The drum portion  61  has a net and allows the first fibers and/or particles of the binding raw material which are contained in the mixture passing through the mixing portion  50  and which are smaller than an opening size of the net to fall down. The structure of the drum portion  61  is, for example, the same as that of the drum portion  41 . 
     In addition, the “sieve” of the drum portion  61  may not have a function to sort a specific object. That is, the “sieve” to be used as the drum portion  61  indicates a member provided with a net, and the drum portion  61  may allows all of the mixture introduced thereinto to fall down. 
     The second web forming portion  70  deposits a passing material passing through the deposition portion  60  to form a web W. The second web forming portion  70  includes, for example, the mesh belt  72 , the tension rollers  74 , and the suction mechanism  76 . 
     While being transferred, the mesh belt  72  allows the passing material passing through openings of the deposition portion  60  to deposit. The mesh belt  72  is stretched by the tension rollers  74  and has the structure in which air is supplied so that the passing material is not likely to pass. The mesh belt  72  is transferred by the rotation of the tension rollers  74 . While the mesh belt  72  is continuously transferred, the passing material passing through the deposition portion  60  is allowed to continuously fall down and deposit, so that the web W is formed on the mesh belt  72 . 
     The suction mechanism  76  is provided under the mesh belt  72 . The suction mechanism  76  can generate a downward air stream. By the suction mechanism  76 , the mixture dispersed in air by the deposition portion  60  can be sucked on the mesh belt  72 . Accordingly, a discharge rate from the deposition portion  60  can be increased. Furthermore, by the suction mechanism  76 , a downflow can be formed in a path in which the mixture falls, and the defibrated material and the additives are prevented from being entangled with each other during the falling. 
     As described above, since passing through the deposition portion  60  and the second web forming portion  70 , the web W can be formed so as to be softly expanded with a large amount of air incorporated therein. The web W deposited on the mesh belt  72  is transported to the sheet forming portion  80 . 
     In addition, in the example shown in the drawing, a moisture control portion  78  which controls moisture of the web W is provided. The moisture control portion  78  can control a mass ratio between the web W and water by adding water or water vapor to the web W. 
     The sheet forming portion  80  forms a sheet S by applying pressure and heat to the web W deposited on the mesh belt  72 . In the sheet forming portion  80 , since heat is applied to a mixture of the defibrated material and the additives mixed in the web W, the fibers in the mixture can be bound to each other with the additives interposed therebetween. 
     The sheet forming portion  80  includes a pressure application portion  82  pressuring the web W and a heating portion  84  heating the web W pressurized by the pressure application portion  82 . The pressure application portion  82  is formed of a pair of calendar rollers  85  and applies a pressure to the web W. Since the web W is pressurized, the thickness thereof is decreased, and the bulk density of the web W is increased. As the heating portion  84 , for example, there may be used a heating roller machine, a hot press forming machine, a hot plate, a hot wind blower, an infrared heater, or a flash fixing device. In the example shown in the drawing, as the heating portion  84 , a pair of heating rollers  86  is provided. Since the heating portion  84  is formed of the heating rollers  86 , compared to the case in which the heating portion  84  is formed as a plate-shaped press machine, the sheet S can be formed while the web W is continuously transported. The calendar rollers  85  and the heating rollers  86  are disposed, for example, so that the rotation shafts thereof are in parallel to each other. In this case, the calendar rollers  85  can apply a higher pressure to the web W than that to be applied to the web W by the heating rollers  86 . In addition, the number of the calendar rollers  85  and the number of the heating rollers  86  are not particularly limited. 
     The cutting portion  90  cuts the sheet S formed by the sheet forming portion  80 . In the example shown in the drawing, the cutting portion  90  includes a first cutting portion  92  cutting the sheet S in a direction intersecting the transportation direction of the sheet S and a second cutting portion  94  cutting the sheet S in a direction in parallel to the transportation direction. The second cutting portion  94  cuts, for example, the sheet S passing through the first cutting portion  92 . 
     Accordingly, a single sheet S having a predetermined size is formed. The single sheet S thus cut is discharged to a discharge portion  96 . 
     According to the apparatus for manufacturing a fiber molded article of this embodiment, since the binding raw material described above is used, the use amount of a petroleum-derived material can be reduced, and the mechanical strengths, such as a tensile strength and a tear strength, and the paper strength of a fiber molded article to be formed can be sufficiently obtained. Furthermore, the fiber molded article to be obtained can be easily recycled. 
     5. Examples and Comparative Examples 
     Hereinafter, with reference to examples and comparative examples, although the present disclosure will be described in detail, the present disclosure is not limited to the following examples. 
     5.1. Production of Binding Raw Material Production Examples 1 to 12 
     After a heater mixer (upper blade: kneading type, a lower blade: high circulation and high loading type, equipped with a heater and a thermometer, volume: 20 L, trade name: Henschel mixer FM20C/I, manufactured by Mitsui Mining Co., Ltd.) was heated to 140° C., a cellulose sheet (Pulp NDP-T manufactured by Nippon Paper Industries Co., Ltd., average fiber diameter: 25 μm, average fiber length: 1.8 mm, content of α-cellulose: 90%, sheet having a width of 20 cm and a length of 80 cm being obtained by cutting a sheet having a width of 60 cm, a length of 80 cm, and a thickness of 1.1 mm) was charged in the above heater mixer, and kneading was performed at an average circumferential velocity of 50 m/sec. After approximately two minutes passed, the cellulose sheet was changed into a cotton-like shape (fiber powder 1). Fiber powders 2 to 5 were formed to have different fiber lengths by changing the cellulose raw material and/or by adjusting the kneading time as described below. 
     Subsequently, after resins 1 to 4 (see below) were each charged in the heater mixer, kneading was performed at an average circumferential velocity of 50 m/sec. An electric power of a motor at this stage was 2.5 kW. When the temperature of the mixer was increased to 120° C., a maleic acid modified polypropylene (MPP) (MG-670P, manufactured by Riken Vitamin Co., Ltd.) was charged, followed by kneading. 
     After approximately 10 minutes passed, the electric power started to increase. After one minute further passed, since the electric power increased to 4 kW, the circumferential velocity was decreased to 25 m/sec. Furthermore, by continuous kneading at a low velocity, the electric power again started to increase. After one minute and 30 seconds passed from the start of the low velocity rotation, since the electric power increased to 5 kW, a discharge port of the mixer was opened, and a mixture thus processed was discharged to a cooling mixer connected thereto. 
     By the cooling mixer (rotation blade: cooling standard blade, equipped with a cooling device (20° C.) and a thermometer, volume: 45 L, trade name: Cooler Mixer FD20C/K, manufactured by Mitsui Mining Co., Ltd.), kneading was started at an average circumferential velocity of 10 m/sec, and when the temperature in the mixer was increased to 80° C., the kneading was stopped. A mixture of the cellulose fibers and the resin was solidified, and pellets having a diameter of several millimeters to approximately 2 cm were obtained therefrom. 
     Resin 1: “Terramac TE-2000”, poly(lactic acid) manufactured by Unitika Ltd.
 
Resin 2: “Zytel HTN510EFT NC010”, bio-polyamide, manufactured by Du Pont.
 
Resin 3: “PHBH”, poly(hydroxyalkanoic acid), manufactured by Kaneka Corporation.
 
Resin 4: “PLANEXT H-5000”, isosorbide-containing resin, manufactured by Teijin Limited.
 
Fiber powder 1: fiber length: 1.5 mm
 
Fiber powder 2: fiber length: 3.0 mm (cotton linter pulp was used without kneading treatment)
 
Fiber powder 3: fiber length: 0.5 mm (manufactured similar to the production example except for that the kneading time was changed to 20 minutes.)
 
Fiber powder 4: fiber length: 0.8 mm (manufactured similar to the production example except for that the kneading time was changed to 10 minutes.)
 
Fiber powder 5: fiber length: 2.0 mm (manufactured similar to the production example except for that the cellulose fibers were changed to cotton linter pulp, and the kneading time was changed to 10 minutes.)
 
Fiber powder 6: fiber length: 1.7 mm (Kevlar, manufactured by Du Pont)
 
     Comparative Production Example 1 
     Except for that the cellulose sheet of Production Example 1 was changed to Kevlar (petroleum-based aramid fibers, fiber length: 1.7 mm, non-natural fibers: fiber powder 6) manufactured by Du Pont-Toray Co., Ltd., production was performed as described above. 
     Comparative Production Example 2 
     Except for that the cellulose sheet of Production Example 1 was not used, production was performed as described above. 
     Comparative Production Example 3 
     Except for that the resin of Production Example 1 was changed to a poly(ethylene terephthalate) (titanium catalyst grade, manufactured by Teijin Limited (Resin 5: thermoplastic petroleum-derived resin), production was performed as described above. 
     Comparative Production Example 4 
     Except for that the resin of Production Example 1 was changed to a pregelatinized cationized starch (M-350B, manufactured by Sansho Co., Ltd.) (Resin 6: thermosetting plant-derived resin), production was performed as described above. 
     Comparative Production Example 5 
     Except for that the resin of Production Example 1 was changed to a rosin ester (AA-V, manufactured by Arakawa Chemical Industries, Ltd.) (Resin 7: thermosetting plant-derived resin), production was performed as described above. 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
            
               
                   
                 PRODUCTION EXAMPLE 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Table 1: 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
                 8 
                 9 
                 10 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 THERMOPLASTIC 
                 RESIN 1 
                 50.0 
                 — 
                 — 
                 — 
                 50.0 
                 50.0 
                 80.0 
                 85.0 
                 30.0 
                 20.0 
               
               
                 PLANT-DERIVED 
                 RESIN 2 
                 — 
                 50.0 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 RESIN 
                 RESIN 3 
                 — 
                 — 
                 50.0 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 RESIN 4 
                 — 
                 — 
                 — 
                 50 0 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 ANOTHER 
                 RESIN 5 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 RESIN 
                 RESIN 6 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 RESIN 7 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 NATURAL 
                 FIBER 
                 50.0 
                 50.0 
                 50.0 
                 50.0 
                 — 
                 — 
                 20.0 
                 15.0 
                 70.0 
                 80.0 
               
               
                 FIBERS 
                 POWDER 1 
               
               
                   
                 FIBER 
                 — 
                 — 
                 — 
                 — 
                 50.0 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 POWDER 2 
               
               
                   
                 FIBER 
                 — 
                 — 
                 — 
                 — 
                 — 
                 50.0 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 POWDER 3 
               
               
                   
                 FIBER 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 POWDER 4 
               
               
                   
                 FIBER 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 POWDER 5 
               
               
                 NON-NATURAL 
                 FIBER 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 FIBERS 
                 POWDER 6 
               
               
                   
               
            
           
           
               
               
               
            
               
                   
                   
                 COMPARATIVE 
               
               
                   
                 PRODUCTION EXAMPLE 
                 PRODUCTION EXAMPLE 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                   
                 Table 1: 
                 11 
                 12 
                 1 
                 2 
                 3 
                 4 
                 5 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 THERMOPLASTIC 
                 RESIN 1 
                 50.0 
                 50.0 
                 50.0 
                 100.0 
                 — 
                 — 
                 — 
               
               
                   
                 PLANT-DERIVED 
                 RESIN 2 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 RESIN 
                 RESIN 3 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                   
                 RESIN 4 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 ANOTHER 
                 RESIN 5 
                 — 
                 — 
                 — 
                 — 
                 50.0 
                 — 
                 — 
               
               
                   
                 RESIN 
                 RESIN 6 
                 — 
                 — 
                 — 
                 — 
                 — 
                 50.0 
                 — 
               
               
                   
                   
                 RESIN 7 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 50.0 
               
               
                   
                 NATURAL 
                 FIBER 
                 — 
                 — 
                 — 
                 — 
                 50.0 
                 50.0 
                 50.0 
               
               
                   
                 FIBERS 
                 POWDER 1 
               
               
                   
                   
                 FIBER 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                   
                 POWDER 2 
               
               
                   
                   
                 FIBER 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                   
                 POWDER 3 
               
               
                   
                   
                 FIBER 
                 50.0 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                   
                 POWDER 4 
               
               
                   
                   
                 FIBER 
                 — 
                 50.0 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                   
                 POWDER 5 
               
               
                   
                 NON-NATURAL 
                 FIBER 
                 — 
                 — 
                 50.0 
                 — 
                 — 
                 — 
                 — 
               
               
                   
                 FIBERS 
                 POWDER 6 
               
               
                   
                   
               
            
           
         
       
     
     5.2. Production of Fiber Molded Article 
     The pellets of the binding raw material obtained in each example were pulverized to form a powdered binding raw material having a volume average particle diameter of 20 μm. After 22.5 g of a conifer bleached kraft pulp and 7.5 g of the binding raw material of each example were measured, the conifer bleached kraft pulp and the binding raw material were charged in this order in a clean polyethylene-made wide mouthed ointment bottle (volume: 1,000 ml) and were then sealed with a lid. The number of rotations of a ball mill rotation stage was adjusted so that a circumferential velocity of the bottle placed thereon was 15 m/min, and the bottle of each example was rotated for 8 minutes. After a mixed product thus obtained of each example was recovered while vibration and an air stream were suppressed as much as possible from being applied thereto, the resin was melted by hot press processing at a temperature of 150° C. and a pressure of 15 MPa for 30 seconds and was then cooled, so that fiber molded articles of the examples and the comparative examples shown in Table 2 were obtained. 
     5.3. Evaluation of Paper Strength (Right after Production) 
     After being cut to have a size of 60 mm×100 mm, the fiber molded article of each example was fixed to an universal tester (AGS-10N, manufactured by Shimadzu Corporation) by holding a top and a bottom end thereof with jigs so that the length of the fiber molded article along a top-to-bottom direction therebetween was 60 mm, a specific tensile strength was measured by pulling the fiber molded article in the top-to-bottom direction. The result was evaluated in accordance with the following criteria and is shown in Table 2. 
     A: 30 Nm/s or more 
     B: 27 to less than 30 Nm/s 
     C: 23 to less than 27 Nm/s 
     D: 20 to less than 23 Nm/s 
     E: less than 20 Nm/s 
     5.4. Evaluation of Paper Strength (after Heat Resistance Test) 
     After the fiber molded article of each example was stored at 90° C. for 30 days, the paper strength was measured in a manner similar to that described above. The evaluation was performed in accordance with the following criteria, and the result thereof is shown in Table 2. 
     A: 99% or more of the tensile strength at the initial stage was maintained. 
     B: 97% to less than 99% of the tensile strength at the initial stage was maintained. 
     C: 95% to less than 97% of the tensile strength at the initial stage was maintained. 
     D: 90% to less than 95% of the tensile strength at the initial stage was maintained. 
     E: less than 90% of the tensile strength at the initial stage was maintained. 
     5.5. Evaluation of Repeated Regeneration 
     The fiber molded article obtained in each example was used as a raw material, and by dry defibration without using any additional raw material, a fiber molded article was regenerated. This operation was performed three times in each example, so that a regenerated fiber molded article of each example was obtained. Subsequently, the paper strength was evaluated as described above. The evaluation result in accordance with the following criteria is shown in Table 2. 
     A: 90% or more of the tensile strength at the initial stage was maintained. 
     B: 80% to less than 90% of the tensile strength at the initial stage was maintained. 
     C: 70% to less than 80% of the tensile strength at the initial stage was maintained. 
     D: 60% to less than 70% of the tensile strength at the initial stage was maintained. 
     E: less than 60% of the tensile strength at the initial stage was maintained. 
     5.6. Evaluation of Fiber Stain 
     The presence or absence of black stains on the surface of the fiber molded article was evaluated by visual inspection, and when no black stains were observed, the black stains were slightly observed, and the black stains were clearly observed, the results were evaluated as A, B, and C, respectively. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
             
            
               
                   
                 EXAMPLE 
                 COMPARATIVE EXAMPLE 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Table 2: 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
                 8 
                 9 
                 10 
                 11 
                 12 
                 1 
               
               
                   
               
               
                 PRODUCTION 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
                 8 
                 9 
                 10 
                 11 
                 12 
                 COMPARATIVE 
               
               
                 EXAMPLE 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 PRODUCTION 
               
               
                 NUMBER OF 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 EXAMPLE 1 
               
               
                 BINDING RAW 
               
               
                 MATERIAL 
               
               
                 PAPER 
                 A 
                 A 
                 A 
                 A 
                 A 
                 C 
                 B 
                 C 
                 B 
                 B 
                 B 
                 A 
                 D 
               
               
                 STRENGTH 
               
               
                 (RIGHT AFTER 
               
               
                 PRODUCTION) 
               
               
                 PAPER 
                 A 
                 A 
                 A 
                 A 
                 A 
                 B 
                 B 
                 C 
                 B 
                 B 
                 B 
                 A 
                 D 
               
               
                 STRENGTH 
               
               
                 (AFTER HEAT 
               
               
                 RESISTANCE 
               
               
                 TEST) 
               
               
                 REPEATED 
                 A 
                 C 
                 A 
                 B 
                 A 
                 A 
                 A 
                 A 
                 A 
                 A 
                 A 
                 A 
                 A 
               
               
                 REGENERATION 
               
               
                 FIBER STAIN 
                 A 
                 A 
                 A 
                 A 
                 B 
                 A 
                 A 
                 A 
                 B 
                 C 
                 A 
                 A 
                 A 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 COMPARATIVE EXAMPLE 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Table 2: 
                 2 
                 3 
                 4 
                 5 
               
               
                   
                   
               
               
                   
                 PRODUCTION 
                 COMPARATIVE 
                 COMPARATIVE 
                 COMPARATIVE 
                 COMPARATIVE 
               
               
                   
                 EXAMPLE 
                 PRODUCTION 
                 PRODUCTION 
                 PRODUCTION 
                 PRODUCTION 
               
               
                   
                 NUMBER OF 
                 EXAMPLE 2 
                 EXAMPLE 3 
                 EXAMPLE 4 
                 EXAMPLE 5 
               
               
                   
                 BINDING RAW 
               
               
                   
                 MATERIAL 
               
               
                   
                 PAPER 
                 E 
                 A 
                 A 
                 E 
               
               
                   
                 STRENGTH 
               
               
                   
                 (RIGHT AFTER 
               
               
                   
                 PRODUCTION) 
               
               
                   
                 PAPER 
                 E 
                 E 
                 A 
                 E 
               
               
                   
                 STRENGTH 
               
               
                   
                 (AFTER HEAT 
               
               
                   
                 RESISTANCE 
               
               
                   
                 TEST) 
               
               
                   
                 REPEATED 
                 A 
                 A 
                 E 
                 C 
               
               
                   
                 REGENERATION 
               
               
                   
                 FIBER STAIN 
                 A 
                 A 
                 A 
                 A 
               
               
                   
                   
               
            
           
         
       
     
     5.7. Evaluation Results 
     As apparent from Table 2, since the defibrated first fibers and the binding raw material in which the thermoplastic plant-derived resin and the natural fibers are integrated with each other are mixed together are heated, it is found that the fiber molded article of each example in which the first fibers are bound to each other with the binding raw material is excellent in paper strength and reproductive property. 
     The present disclosure is not limited to the embodiments described above and may be further variously changed and/or modified. For example, the present disclosure includes substantially the same structure (the same structure in terms of the function, the method, and the result or the same structure in terms of the object and the effect) as the structure described in the embodiment. In addition, the present disclosure includes the structure in which a nonessential portion of the structure described in the embodiment is replaced with something else. In addition, the present disclosure includes the structure which performs the same operational effect as that of the structure described in the embodiment or the structure which is able to achieve the same object as that of the structure described in the embodiment. In addition, the present disclosure includes the structure in which a known technique is added to the structure described in the embodiment.