JP6706501B2 - Molding material - Google Patents

Description

The present invention relates to give Ru granulation type method 3D object using a fused deposition modeling 3D printer.

3D printers that create three-dimensional things based on blueprints on computers can easily make plastic parts, jigs, and products without using molds and melting equipment. It is spreading rapidly. In particular, a low-priced 3D printer of a hot melt lamination method using a thermoplastic resin as a molding material is also sold, and it is becoming popular with individuals.

As a molding material used for such a hot melt laminating method 3D printer, a linear resin molded product (monofilament-shaped product) having a diameter of several mm and continuous in the longitudinal direction is commercially available and used. .. For example, in Patent Document 1, as a high-precision modeling material, the average diameter is 0.069 to 0.074 inches (about 1.75 to 1.90 mm), and the length is 20 feet (about 6.1 m) or more, A build material (feed) having a standard deviation in diameter of 0.0004 inches (0.01 mm) or less is disclosed. In addition, as a thermoplastic resin constituting such a molding material, a thermoplastic resin such as ABS resin, polycarbonate, polyamide, polylactic acid is used.

In addition, when creating a molded article using such a material, if it is desired to color the molded article with a desired color, a commercially available molding material colored in that color may be used, but it is commercially available. Therefore, it often happens that a molding material having a desired color cannot be obtained. Patent Document 2 discloses an apparatus for obtaining a multicolored object. According to Patent Document 2, a print head that coats an additive such as a stored pigment is provided in front of a melt extrusion nozzle in a 3D printer to obtain a modeled product whose surface is colored in a desired color. You can

When a commercially available molding material colored in a desired color is not available, a 3D printer device such as that of Patent Document 2 may be used to obtain a colored molded article using a pigment of a desired color. However, since the device as in Patent Document 2 is complicated and expensive, it cannot be applied to a printer which is generally commercially available.

Japanese Patent Publication No. 2005-523391 Special table 2014-516829 gazette

The molding material made of the continuous linear resin molding (monofilament-shaped material) described above is hard and cannot be said to be easy to handle. Above all, the molding material made of polylactic acid is particularly hard. , The state of being wound on the bobbin, etc. is released as soon as the winding tension is slightly relaxed, and it is disengaged from the bobbin and scattered (this situation is called “crash occurrence”). Also called.). Further, among the polylactic acid molding materials that are sold in the market, those that have not been crystallized have a problem that they tend to break during use.

In view of such a situation, the present inventor studied to provide a modeling method using a modeling material for a hot-melt laminating 3D printer, which is easy to handle. It was common knowledge that the shape of the material for the hot melt laminating 3D printer was a so-called monofilament-like material, but it was considered that other forms could be applied without being bound by that common knowledge. The present inventors invented one continuous filament-like molding material by concentrating two synthetic fibers (Japanese Patent Application No. 2015-24247). Then, using the present invention, during various studies, it is possible to easily add an additive such as a pigment and easily provide a modeling material applicable to a general-purpose 3D printer. As a result of examination, the present invention has been reached. An object of the present invention is to provide a modeling method using a modeling material that can be applied to a general-purpose 3D printer and to which additives such as various pigments can be easily added.

According to the present invention, a modeling material having the following form is supplied to a hot melt laminating method 3D printer, and a modeling head melts a thermoplastic resin constituting a plurality of thermoplastic synthetic fibers constituting the modeling material by heating. Is a molding method characterized by creating a desired three-dimensional model by injecting and stacking from a nozzle.
The form of the molding material is a continuous thread-like form in which a plurality of thermoplastic synthetic fibers are bundled, and at least a part of the plurality of thermoplastic synthetic fibers is a functional additive. A plurality of thermoplastic synthetic fibers containing the above and constituting a modeling material are melted by a modeling head in a hot melt laminating method 3D printer .

Hereinafter, the present invention will be described in detail.

In the present invention, the modeling material used in the hot-melt laminating method 3D printer is a material for supplying the hot-melt laminating method 3D printer to obtain a three-dimensional structure, and is composed of a thermoplastic resin. Using this modeling material, based on the design drawing on the computer, the modeling head melts the thermoplastic resin that constitutes the modeling material by heating, and it is injected from the nozzle and laminated to form a three-dimensional modeled object of the desired shape. Create it.

The modeling material in the present invention is composed of thermoplastic synthetic fibers. As the thermoplastic resin constituting the synthetic fiber, any one that can be melted at the melting temperature of the modeling head in the hot melt laminating method 3D printer can be used, and the one having a melting point of 180° C. or lower is preferable, and for example, an aliphatic resin. Examples thereof include polyester resins, aromatic polyester resins, polyamide resins, polyolefin resins, acrylic resins, polycarbonate resins, acrylonitrile-butadiene-styrene copolymer resins, and fluororesin resins. You may use what mixed these resins. Of these, polylactic acid is preferable because it is less likely to warp, and poly L lactic acid having a low D-form content is more preferable because it is unlikely to have a yellowish tint. By adjusting the D-form content, the melting point of the polylactic acid can be adjusted according to the temperature control of the printer, but in order to make it less yellowish, the D-form content is less than 1.5%. Things are good. Also, in the method for producing synthetic fibers using the above-mentioned resin, although not particularly limited, when producing fibers using a thermoplastic resin having crystallinity, the stretching step and heat shrinkage are controlled. It is recommended to apply a relaxation process for manufacturing during the manufacturing process.

The molding material in the present invention has a single continuous thread-like form in which a plurality of thermoplastic synthetic fibers are bundled. Examples of the method for bundling a plurality of synthetic fibers include a twisting method, a braiding method, and a heat-bonding method by heat treatment. More specifically, a method in which a plurality of synthetic fibers are twisted and bundled, and a method in which two or more bundles in which a plurality of synthetic fibers are aligned or twisted are braided and bundled into a braid , A method in which a part of the thermoplastic resin constituting the synthetic fiber is melted or softened by subjecting a plurality of synthetic fibers aligned to each other to heat treatment, and the fibers are thermally adhered to each other, or these (or A method in which twisting, braiding, and heat bonding) are combined is included.

The molding material in the present invention is configured by bundling a plurality of thermoplastic synthetic fibers as described above, and at least a part of the fibers of the plurality of thermoplastic synthetic fibers contains a functional additive. To do. As a functional additive, in order to impart a desired function to the three-dimensional model to be created, it is added to the modeling material that is the material, and is an antioxidant, a weather resistance agent, an antistatic agent, a dispersant. , Lubricants, flame retardants, colorants, antibacterial agents, heat conductive materials, conductive materials, fragrances, water soluble materials, smoothing agents, plasticizers, X-ray opaque agents, fillers, impact modifiers, crystal accelerators , A compatibilizing agent and the like.

As the additive, more specifically, examples of the antioxidant include phenolic compounds, organic phosphite compounds, organic phosphorus compounds such as nasnite, and thioether compounds.
Examples of the weather resistance agent include hindered amine-based, benzophenone-based, benzotriazole-based, and benzoate-based agents.
Examples of the antistatic agent include nonionic, cationic and anionic agents.
Examples of the dispersant include bisamide type, wax type and organic metal salt type dispersants.
Examples of the lubricant include amide type, wax type, organic metal salt type and ester type.
Examples of the flame retardant include bromine-containing organic type, phosphoric acid type, antimony trioxide type, magnesium hydroxide type, ammonium phosphate type and red phosphorus.
Examples of the colorant include pigments such as carbon black, titanium oxide, perylene pigments, quinacridone pigments, and phthalocyanine pigments, and dyes such as azo pigments, indigo pigments, quinone pigments, xanthene pigments, and pyridone benzodifuranone pigments. In addition, fluorescent/phosphorescent dyes such as quinoline-based, pyridinone-based and organometallic dyes, and chromic dyes such as vanadium oxide, polydiacetylene-based and viologen-based dyes can also be used.
Examples of antibacterial agents include silver-based, copper-based, silver-zeolite-based, photocatalytic titanium oxide-based, organic nitrogen-sulfur compound-based, isothiazolone-based, carboxylic acid-based, and organometallic-based agents.
Examples of the heat conductive material include metal-based materials, carbon-based materials, ceramic-based materials, and silicate mineral-based materials.
Examples of the conductive material include metal-based materials, carbon-based materials, ceramic-based materials, conductive polymer-based materials, and surfactants.
Examples of the fragrance include natural fragrances, synthetic fragrances, compounds generating fragrance, and the like, and more specifically, animal fragrances such as vegetable essential oils and musks, and synthetic fragrances such as limonene and nerolidol.
Examples of the water-soluble material include polyvinyl alcohol type, starch type, acrylic acid type and the like.
Examples of the leveling agent include silicone type, fluorine type and wax type.
Examples of the plasticizer include phthalic acid-based, adipic acid-based, phosphoric acid-based, wax-based and the like.
Examples of the X-ray opaque agent include barium sulfate, lead-based agents, and tungsten-based agents.
Examples of the filler include metal-based, carbon-based, glass-based, cellulose-based and the like.
Examples of the impact resistance improver include other polymers, elastomers and core shell type impact resistance improvers.
Examples of the crystallization accelerator include metal oxide type, silicate type, fatty acid ester type, organic sulfonate type, phosphoric acid ester metal salt type, glycerin type and polyalkylene glycol type.
Examples of the compatibilizer include ethylene vinyl alcohol-based, styrene-based, ester-based and amide-based agents.

These functional additives are contained in the thermoplastic synthetic fibers constituting the molding material. As a method of containing the additives, for example, one or two or more of the above-mentioned additives may be appropriately combined and mixed in the step of producing a thermoplastic polymer composition to be a material of synthetic fibers. The additives may be blended at a predetermined ratio using a kneading device such as a conventionally known single-screw or twin-screw extruder Banbury mixer, kneader, and mixing roll, and melt-kneaded to adjust the mixture. Alternatively, a high-concentration so-called masterbatch may be prepared and diluted to use.

It is also possible to incorporate the additive into a synthetic fiber or a bundle of a plurality of synthetic fibers by dipping or exhausting the additive in a subsequent step. For example, a dye can be supported on the surface and inside of the synthetic fiber by a conventionally known method such as vat dyeing and washer dyeing. In the case of dyeing, if necessary, an auxiliary agent such as a carrier, a leveling agent, a pH adjusting agent or the like can be used, and a refining, soaping or fixing step can be added.

The content of the functional additive may be an amount capable of exhibiting a desired function, and may be appropriately designed according to the kind of the additive and the like.

Of the plurality of thermoplastic synthetic fibers forming the molding material, all the synthetic fibers may contain a functional additive. Further, only some of the synthetic fibers may contain a specific functional additive. Further, even if the plurality of synthetic fibers constituting the modeling material include different additives, respectively, a plurality of synthetic fibers containing different additives are bundled, and the molding material may include a plurality of types of additives. Good. By appropriately combining the synthetic fiber containing the additive and the synthetic fiber not containing the additive in this manner, the amount of the functional additive contained in the modeling material can be easily adjusted to a desired amount. Further, by combining synthetic fibers containing a specific additive with each other and bundling them, a molding material capable of imparting various functionalities can be obtained, and a three-dimensional structure capable of exhibiting various functions can be easily obtained. it can.

In the present invention, as a specific method for bundling a plurality of synthetic fibers, the method described in the invention (Japanese Patent Application No. 2015-24247) proposed by the applicant of the present application may be applied. I will describe.

In the method in which a plurality of synthetic fibers are aligned and twisted to be bundled, it is preferable to fix the twisted form by performing heat treatment, since it is easy to loosen from the end in the case of single twist. During the heat treatment, it is also preferable to perform a treatment at a temperature at which a part of the thermoplastic resin forming the fibers is melted or softened, and the fibers are thermally bonded to fix the shape. Even with twisted yarns other than single-twisted yarns, it is possible to adjust the texture and improve the bundle density between fibers by heat treatment.

Further, it is also preferable that two or more single-twisted fiber bundles are twisted in a direction opposite to the single-twisted direction to be bundled, and so-called ply twisting is performed to make it difficult to untwist. Furthermore, it is also preferable to heat-treat after twisting and to fix the shape by heat fixing or heat bonding. As the twisting direction of the single-twisted fiber bundle before ply-twisting (lower twisting direction), a fiber bundle twisted in the same direction shall be selected, and the number of lower twists may be appropriately adjusted according to the fineness. It is good, but about 50 to 1000 times/m is preferable. The number of ply twists (top twists) may be appropriately designed according to the thickness and the number of fiber bundles used.

In the method of bundling by using two or more fiber bundles for bundling, any of flat striking, square striking and round striking may be applied. Among them, since many continuous linear objects having a circular cross section are currently used as a feed material for the hot melt laminating 3D printer, a braid by round punching is preferable. In the case of round striking, it is preferable that the number of striking is 4 or more, more preferably 8 or more, and further preferably 16 in order to obtain a more perfect circular shape. In addition, as a form of a round braid, a braid is inserted in the center of the braid in the longitudinal direction (axial direction), and a plurality of yarns are arranged as side yarns around the core yarn. Is preferably adopted. This is because in the cross section of the obtained molding material, the density of the central portion is also high, and void portions are unlikely to occur.

Similarly to the above-mentioned twisted yarn, the braid can be heat treated to adjust the texture and improve the bundle density between the fibers.

In the present invention , when a modeling material formed by bundling a plurality of thermoplastic synthetic fibers is set in a 3D printer and used, the end face is melted and cut, so that the bundling state may be unraveled. Absent. However, a fiber made of a thermoplastic synthetic resin having a low melting point is mixed as the thermoplastic synthetic fiber to be bundled, and after being converged by twisting or stringing, a heat treatment is performed at a temperature at which the thermoplastic synthetic resin having a low melting point is melted, It is also preferable that the thermoplastic synthetic resin having a low melting point is caused to function as a thermal adhesive and the constituent fibers are thermally adhered to each other to improve the focusing property. Further, by mixing the low melting point thermoplastic synthetic fibers and thermally adhering them, the density of the modeling material becomes high and the shape retention is also improved.

In the present invention, as the form of the thermoplastic synthetic fiber, all continuous fibers may be selected, but short fibers having a specific fiber length may be used. When short fibers are used, a continuous thread-like molding material may be formed by bundling spun yarn obtained by spinning a group of short fibers or a mixed spun yarn obtained by mixing continuous fibers and short fibers. Such spun yarn may be used as a bundle of thermoplastic synthetic fibers to obtain a braid or plied yarn. A textured yarn made of continuous fibers may also be used. Examples of the textured yarn include air entangled yarn, false twisted yarn, and BCF (Bulked Continuous Filament).

Even when all the continuous fibers are selected as the plurality of fibers constituting the molding material, continuous fibers having different fineness may be mixed. When using continuous fibers having different fineness, a composite yarn in which a filament having a large fineness is braided with a multifilament, or a composite yarn in which a filament having a large fineness is wound with a multifilament is formed into a continuous filamentous shape It can also be a form of the molding material. Monofilament yarn may be used as the filament having a high fineness. For example, by disposing the monofilament yarn in the center of the molding material, the density of the center becomes uniform. Further, when a monofilament yarn having a low-melting point heat-adhesive component on the fiber surface is arranged in the center of the molding material, heat treatment is performed so that the monofilament yarn is heat-bonded to the fibers arranged in the periphery to be well integrated and bundled preferable.

The single fiber fineness of the thermoplastic synthetic fiber may be appropriately designed in consideration of the number of yarns at the time of bundling, the diameter of the molding material, the density at the time of bundling, and the durability. For example, when the monofilament fineness is large, the durability against friction and the like is high, but the gap between fibers becomes large, and voids may occur during modeling. Also, the cross-sectional shape of the single fiber may be appropriately designed in consideration of handleability and density when bundled. Examples thereof include round shape, elliptical shape, polygonal shape (triangular shape, square shape, etc.), multilobal shape (cross shape, star shape, etc.), and fibers having different cross-sectional shapes may be used in combination.

According to the present invention, it is possible to provide a modeling material for a hot melt laminating 3D printer which is flexible and has good handleability, and the amount of the functional additive contained in the modeling material can be easily adjusted to a desired value. By adjusting the amount and by combining synthetic fibers containing additives and converging, a molding material capable of imparting various functionalities can be obtained, and a three-dimensional molded object that can easily exhibit various functions can be obtained. Obtainable.

Next, the present invention will be specifically described with reference to examples.
The physical properties of the fiber were tested according to JIS-L-1013. For handling, 1 kg was wound on a bobbin having an inner diameter of 100 mm for evaluation. Further, for the evaluation test of the 3D printer, using SCOOVO C170 manufactured by Abbey Co., a cube having a molding temperature of 230° C., a stacking pitch of 0.1 mm, a density of 100% and a side of 3 cm was prepared, and its appearance was confirmed.

Example 1
A polylactic acid chip (Nature Works (6201D): D-form content: 1.4%) was mixed with 10% by mass of carbon black and 1% by mass of copper iodide to produce a master chip. 4 parts by mass of this master chip And 96 parts by mass of the above polylactic acid chip (Nature Works (6201D)) are mixed, melt-spun and stretched using an extruder type spinning machine, and the strength is 4.0 cN/dtex and the elongation is 1900 dtex of 30%. A multifilament made of /210f of the primary dyed polylactic acid fiber was obtained. Sixteen multifilaments made of the polylactic acid fiber were stringed by a round punching string machine, and then heat set at 100° C. for 2 minutes to obtain a molding material of Example 1.

Example 2
Using a polylactic acid chip (Nature Works (6201D): D-form content 1.4%), melt spinning and stretching with an extruder type spinning machine, strength 4.0 cN/dtex, elongation 30% A colorless multifilament composed of 1900 dtex/210f of polylactic acid fiber was obtained.
16 colorless multifilaments made of the polylactic acid fibers and 16 multifilaments made of the primary-coated polylactic acid fibers used in Example 1 were braided by a round striking machine, and then 100°C for 2 minutes. Heat setting was performed to obtain the modeling material of Example 2.

Example 3
Twelve colorless multifilaments made of polylactic acid used in Example 2 and four multifilaments made of the primary-coated polylactic acid fibers used in Example 1 were braided by a 16-round punching machine and then Heat setting was performed at 100° C. for 2 minutes to obtain the modeling material of Example 3.

Comparative Example Polylactic acid chips (Nature Works (6201D): D-form content 1.4%) were melt-spun and stretched by an extruder type spinning machine to obtain a strength of 3.5 cN/dtex and an elongation of 28% of polylactic acid monofilament having 30,000 dtex (diameter: about 1.75 mm) was obtained.

Table 1 shows the evaluation results of Examples 1 to 3 and Comparative Example. According to the modeling method of the present invention, a good three-dimensional three-dimensional molded product can be obtained by applying it to a hot melt laminating 3D printer, and the modeling material of the present invention is more flexible and easier to handle than the monofilament of Comparative Example. The property was good. Further, as a combination of multifilaments constituting the molding material, by appropriately adjusting the number of colored multifilaments, the amount of the coloring agent contained as the molding material can be adjusted, and a three-dimensional molded object having a shade It was confirmed that it was possible to easily provide.

Example 4
Using a polylactic acid chip (Nature Works (6201D): D-form content 1.4%), melt spinning and stretching with an extruder type spinning machine, a colorless multi-fiber made of polylactic acid fiber of 560 dtex/96 filaments. A filament was obtained.
On the other hand, the following fibers were obtained as fibers containing a functional additive. That is, the above-mentioned polylactic acid chip and carbon black as a colorant were melt-kneaded by a twin-screw extruder to obtain a kneaded chip. At this time, the blending amount of carbon black was 0.5% by mass in the kneading chips. This kneading chip was melt-spun and stretched by an extruder type spinning machine to obtain a monofilament containing a colorant of 560 dtex/1f.

The obtained fiber bundle obtained by aligning 3 multifilaments and 2 monofilaments is twisted by Z twisting 60 times/m (Z-60) using a ring twisting machine to obtain a twisted yarn. 7 were bundled and subjected to upper twisting with S twisting 150 times/m (S-150) using a ring twisting machine to obtain plied yarns. The obtained plied yarn was heat-treated at 165° C. for 1 minute to obtain a modeling material of Example 4 having a wire diameter of 1.75 mm. In the obtained molding material, the constituent fibers were solidified by softening and shrinking during heat treatment.

Example 5
A molding material of Example 5 was obtained in the same manner as in Example 4, except that the following fibers were used as the fibers containing the functional additive. In the obtained molding material, the constituent fibers were solidified by softening and shrinking during the heat treatment.
The fiber containing the functional additive was obtained as follows. That is, the polylactic acid chips used in Example 4 and silver-zeolite as an antibacterial agent were melt-kneaded by a twin-screw extruder to obtain kneaded chips. At this time, the blending amount of silver-zeolite was 5% by mass in the kneading chips. This kneading chip was melt-spun and stretched by an extruder type spinning machine to obtain a monofilament containing an antibacterial agent at 560 dtex/1f.

Example 6
A molding material of Example 6 was obtained in the same manner as in Example 4 except that the following fibers were used as the fibers containing the functional additive. In the obtained molding material, the constituent fibers were solidified by softening and shrinking during the heat treatment.
The fiber containing the functional additive was obtained as follows. That is, the polylactic acid chip used in Example 4 and conductive carbon black as a conductive material were melt-kneaded with a twin-screw extruder to obtain a kneaded chip. At this time, the blending amount of the conductive carbon black was 10% by mass in the kneading tip. This kneading chip was melt-spun and stretched by an extruder type spinning machine to obtain a monofilament containing a conductive material of 560 dtex/1f.

Example 7
A molding material of Example 7 was obtained in the same manner as in Example 4, except that the following fibers were used as the fibers containing the functional additive. In the obtained molding material, the constituent fibers were solidified by softening and shrinking during the heat treatment.
The fiber containing the functional additive was obtained as follows. That is, the polylactic acid chip used in Example 4 and barium sulfate as an X-ray opaque agent were melt-kneaded by a twin-screw extruder to obtain a kneading chip. At this time, the blending amount of barium sulfate was 10% by mass in the kneading chips. This kneading chip was melt-spun and stretched by an extruder type spinning machine to obtain a monofilament containing 560 dtex/1f of an X-ray opaque agent.

Example 8
The polylactic acid chip used in Example 4 was melt-spun and stretched by an extruder type spinning machine, and the resulting filament was mechanically crimped and then cut to obtain a single yarn fineness of 2.2 dtex, fiber. A colorless staple fiber having a length of 51 mm was obtained. This staple fiber was spun to obtain a colorless spun yarn of 20 count.
The colorless spun yarn obtained above was dyed with a disperse dye using a pressure hot dyeing machine to obtain a dyed yarn dyed in pink.
A fiber bundle in which eight colorless spun yarns were aligned was subjected to undertwisting at a Z twist of 60 times/m (Z-60) using a ring twisting machine to obtain a colorless twisted yarn. On the other hand, a fiber bundle obtained by drawing eight dyed yarns together was subjected to undertwisting at a Z twist of 60 times/m (Z-60) using a ring twisting machine to obtain a dyed yarn. Seven colorless twisted yarns and one dyed twisted yarn were bundled and plied with S twisting 150 times/m (S-150) using a ring twisting machine to obtain plied yarns. The obtained plied yarn was heat-treated at 165° C. for 1 minute to obtain a modeling material of Example 8 having a wire diameter of 1.75 mm. In the obtained molding material, the constituent fibers were melted and fixed to each other by thermal bonding by heat treatment.

When the winding evaluation (bobbin winding property) and the 3D printer evaluation test (3D printer output) were performed using the modeling materials obtained in Examples 4 to 8, in any material, the winding evaluation was performed. Was able to be rolled up flexibly and neatly, and when it was output by a 3D printer, it could be neatly output and had a glossy feeling, and a shaped article having various functions was obtained. Further, also in the operation of feeding the molding material into the 3D printer, the feeding operation was performed favorably without any problem in the feeding device.

Claims (7)

The molding material of the following form is supplied to the hot melt laminating method 3D printer, and the molding head melts the thermoplastic resin constituting the plurality of thermoplastic synthetic fibers constituting the molding material by heating, and from the nozzle. It is a molding method characterized by creating a three-dimensional molded object of a desired shape by injecting and laminating.
The form of the molding material is a continuous thread-like form in which a plurality of thermoplastic synthetic fibers are bundled, and at least a part of the plurality of thermoplastic synthetic fibers is a functional additive. A plurality of thermoplastic synthetic fibers containing the above and constituting a modeling material are melted by a modeling head in a hot melt laminating method 3D printer. The molding method according to claim 1, wherein the melting point of the thermoplastic resin that constitutes the thermoplastic synthetic fiber is 180° C. or lower. The modeling method according to claim 1, wherein the functional additive is a colorant. The thermoplastic synthetic fiber bundle composed of a plurality of fibers is made into a continuous thread-like form by bundling two or more strings and presenting one continuous thread-like form. Modeling
Way . The thermoplastic synthetic fiber bundle composed of a plurality of fibers is twisted in two or more bundles to be bundled to form a single continuous thread-like form. Modeling method. The molding method according to any one of claims 1 to 5, wherein a bundle of a plurality of thermoplastic synthetic fibers has a twist. 7. The modeling method according to claim 1, wherein the thermoplastic synthetic fibers are bundled by heat fusion.