JP6153680B1 - Modeling material for 3D printer, manufacturing method thereof, and three-dimensional modeled object - Google Patents

Abstract

[PROBLEMS] To disperse nanofibers such as cellulose nanofibers uniformly in a thermoplastic resin, thereby improving strength and elastic modulus, reproducing a fine pattern surface state, excellent surface smoothness, transparency and To provide a modeling material for a 3D printer from which a three-dimensional modeled object having excellent dyeability can be obtained. A modeling material for a 3D printer comprising (A) nanofibers, (B) a dispersant, and (C) a resin component as main components. [Selection figure] None

Description

  The present invention relates to a modeling material used when a three-dimensional model is obtained by a 3D printer.

3D printers that create three-dimensional printers based on computer design data can produce plastic parts, jigs, and products without using molds or melt molding equipment. It is popular. In particular, a hot melt lamination type 3D printer using a thermoplastic resin as a modeling material is also sold as a low-priced version and is beginning to spread to individuals.
As a modeling material used for such a hot melt lamination type 3D printer, a functional resin composition including a thermoplastic resin and functional nanofillers dispersed in the resin has been proposed (Patent Document 1). The technical essence of this patent document is to knead carbon nanofibers or nanoclay particles with a twin screw kneading extruder using supercritical carbon dioxide, and does not use a dispersant. In this case, the dispersion of the nanofiller is not sufficient, and the function of the original nanofiller cannot be sufficiently exhibited, and the cellulose nanofiber is merely exemplified as the nanofiber.

JP 2016-28887 A

  In the present invention, the nanofibers such as cellulose nanofibers are uniformly dispersed in the resin, thereby improving the strength and elastic modulus, improving the strength and elastic modulus, and reproducing the design shape more accurately as a modeled object. An object of the present invention is to provide a modeling material for a 3D printer capable of obtaining a three-dimensional modeled object that is excellent in surface smoothness and further excellent in transparency and dyeability.

This invention is comprised by the following (1)-(9).
(1) A modeling material for a 3D printer, the modeling material having (A) nanofibers, (B) a dispersant, and (C) a resin component made of a thermoplastic resin or a photocurable resin as a main component.
(2) (A) The modeling material according to (1), wherein the nanofiber is a cellulose nanofiber.
(3) The modeling material according to claim 2, wherein the average fiber diameter of (A) cellulose nanofiber is 10 to 100 nm.
(4) The modeling material according to any one of (1) to (3), wherein (B) the dispersant is mainly composed of a (meth) acryloyloxyethyl phosphorylcholine (co) polymer.
(5) (B) The (meth) acryloyloxyethyl phosphorylcholine (co) polymer constituting the dispersant is polymethacryloyloxyethyl phosphorylcholine, polybutyl methacrylate / methacryloyloxyethyl phosphorylcholine and polystearyl methacrylate / methacryloyloxyethyl phosphorylcholine The modeling material according to (4), which is at least one selected from the group of
(6) (C) The resin component is a polyethylene resin, polypropylene resin, polylactic acid resin, polyvinyl alcohol resin, polyamide resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate resin, The modeling material according to any one of (1) to (5), which is at least one selected from the group consisting of polyvinylidene chloride resin, ethylene vinyl alcohol resin, polyacrylonitrile resin, polyacetal resin, polyketone resin, and cyclic polyolefin resin .
(7) In terms of solids, (A) nanofiber is 0.5 to 20% by weight, (B) dispersant is 0.0005 to 10% by weight, and (C) resin is 70 to 99.4949% by weight [however, (A) + (B) + (C) = 100% by weight] The modeling material according to any one of (1) to (6).
(8) Manufacture of modeling material for 3D printer characterized by melting and extruding the modeling material according to any one of (1) to (7) above, and then cooling and solidifying in a liquid bath to form a monofilament yarn. Method.
(9) A three-dimensional structure obtained by applying a 3D printer using the modeling material according to any one of (1) to (7) above.

  In the modeling material of the present invention, (A) nanofibers such as cellulose nanofibers are (B) due to the action of the dispersant, the nanofibers are entangled in nano order, and further, aggregation due to hydrogen bonding of cellulose hydroxyl groups is blocked, Since it is uniformly dispersed in the resin component (C), the strength and elastic modulus are improved, and the nanofibers are dispersed, so the design shape can be reproduced more accurately as a modeled object, and the surface smoothness In addition, when cellulose nanofibers are used as nanofibers, they are also excellent in transparency and dyeability, the dispersion diameter of cellulose nanofibers is small depending on the wavelength of light, and the dyeability due to cellulose is also high. A modeling thing is obtained and it is suitable as modeling material for 3D printers.

It is a photograph of 3D printer modeling thing (M16 hexagon bolt) obtained in Example 2.

  Hereinafter, although the modeling material for 3D printers of the present invention will be described in detail according to the constituent requirements, the modeling material of the present invention has (A) nanofibers, (B) a dispersant, and (C) a resin component as main components. .

<(A) Nanofiber>
Nanofiber is a general term for fibers generally having a diameter of 1 to 1,000 nm and a length of 100 times or more of the diameter. Examples of nanofiber materials include bio-nanofibers (cellulose nanofibers, chitin / chitosan nanofibers), carbon nanofibers, and other nanofibers (inorganic nanofibers other than carbon, organic polymer nanofibers). Is a cellulose nanofiber. Hereinafter, (A) nanofiber will be described in detail by taking cellulose nanofiber as an example.

<Raw material of cellulose nanofiber>
Here, (A) The raw material of the cellulose used for manufacture of a cellulose nanofiber may be arbitrary forms, such as fibrous form and a granular form. The cellulose raw material is preferably crystalline cellulose from which lignin and hemicellulose have been removed. Commercially available raw materials may be used. When cellulose is processed with a medialess disperser, the cellulose is untangled and thins while maintaining the length of the fiber. However, it is possible to cut the fiber or reduce the molecular weight by changing the processing conditions. is there. In the present invention, “nanofiber” means a fiber having a nano width as described above. For example, the diameter of cellulose is about 4 to 10 nm when the fibers of the present invention are sufficiently defibrated to become the smallest unit of fiber by carrying out the method of the present invention. The diameter (width) of the cellulose raw material or nanofiber can be measured by an electron micrograph. Such a fiber is not nano-sized, but its diameter (width) is nano-sized, and is therefore referred to as nanofiber in the present invention.

<(B) Dispersant>
(B) Any dispersant may be used as long as it can disperse (A) cellulose nanofibers. For example, “P-OH group, —COOH group, —SO ₃ H group, and / or an anionic dispersant in which at least one of these metal bases is bonded” (Japanese Patent Laid-Open No. 2012-51991), resin affinity “Dispersant having segment A and cellulose affinity segment B and having a block copolymer structure or a gradient copolymer structure” (Japanese Patent Application Laid-Open No. 2014-162880), among others, A dispersant containing a (meth) acryloyloxyethyl phosphorylcholine (co) polymer having good affinity with the resin component is preferable.

(Meth) acryloyloxyethyl phosphorylcholine (co) polymer:
Here, the term “(meth) acryloyloxyethyl phosphorylcholine” is a general term for methacryloyloxyethyl phosphorylcholine and acryloyloxyethyl phosphorylcholine. These are produced according to conventional methods. That is, for example, 2-bromoethyl phosphoryl dichloride, 2-hydroxyethyl phosphoryl dichloride and 2-hydroxyethyl methacrylate are reacted to obtain 2-methacryloyloxyethyl-2'-bromoethyl phosphate, It can be obtained by reacting trimethylamine with methanol solution.

  As a method for producing a polymer (homopolymer) using such (meth) acryloyloxyethyl phosphorylcholine (hereinafter “MPC”), a normal polymerization method may be followed. For example, polymerization of these monomers in a solvent is started. It is obtained by reacting in the presence of an agent. The solvent used here may be any solvent that can dissolve MPC. Specifically, water, methanol, ethanol, propanol, t-butanol, benzene, toluene, dimethylformamide, tetrahydrofuran, chloroform, or a mixed solvent thereof. Etc. are exemplified. As the polymerization initiator, any normal radical initiator may be used, such as 2,2′-azobisisobutyronitrile (AIBN), 3-carboxypropionitrile, azobismaleonitrile and the like. Examples thereof include organic peroxides such as fatty acid azo compounds, benzoyl peroxide, lauroyl peroxide, and potassium persulfate.

  When preparing a copolymer (copolymer), in addition to these monomers, arbitrary monomers can be further added and polymerized in the same manner. Examples of the optional monomer include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, lauryl acrylate, methacrylic acid Alkyl (meth) acrylates such as lauryl, cetyl acrylate, cetyl methacrylate, stearyl acrylate, stearyl methacrylate, isostearyl acrylate, isostearyl methacrylate, oleyl acrylate, oleyl methacrylate, acrylic acid , (Meth) acrylic acid such as methacrylic acid or salts thereof, polyoxyethylene acrylic acid, polyoxyethylene methacrylic acid, polyoxypropylene acrylic acid, polyoxypropylene methacrylic acid and other polyoxy Alkylene-modified (meth) acrylic acid can be preferably exemplified. The copolymerization method is not particularly limited as long as it is a generally known method, and random copolymerization, block copolymerization and the like can be preferably exemplified.

  Some of such polymers or copolymers are already commercially available, and such commercially available products can be purchased and used. Examples of such commercially available products include “Lipidure HM” (manufactured by Nippon Oil & Fats Co., Ltd.), which is polymethacryloyloxyethyl phosphorylcholine, and “Lipidure PMB” (Nippon Oil Co., Ltd.) which is a methacryloyloxyethyl phosphorylcholine / butyl methacrylate copolymer. Preferred examples include “Lipidure NR” (manufactured by NOF Corporation), which is a methacryloyloxyethyl phosphorylcholine / stearyl methacrylate copolymer. The dispersant made of the (co) polymer has biocompatibility like the cellulose nanofiber, and the three-dimensional structure made of the material for 3D printer according to the present invention can be suitably used for medical or food applications.

In addition to (meth) acryloyloxyethyl phosphorylcholine (co) polymer, (B) dispersing agent includes phosphoric acid or polyphosphoric acid, phosphoric acid or polyphosphoric acid salt, polyacrylic acid, polyacrylic acid as described above. You may mix | blend other commonly used dispersing agents, such as anionic dispersing agents, such as an acid copolymer, the salt of polyacrylic acid, and the salt of polyacrylic acid copolymer.
Further, the cellulose nanofiber dispersion comprising the components (A) to (B) of the present invention includes acids such as phosphoric acid, citric acid, acetic acid and malic acid, alkalis such as sodium hydroxide and potassium hydroxide, sodium carbonate A small amount of alkali such as potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate may be added.

<Dispersion medium>
In the present invention, a dispersion (emulsion or slurry) is first prepared from (A) cellulose nanofibers and (B) a dispersant. In this case, a dispersion medium is used.
As a dispersion medium of cellulose nanofiber dispersion, water, lower alcohol (methanol, ethanol, propanol, isopropanol), glycols (ethylene glycol, propylene glycol, diethylene glycol), glycerin, acetone, dioxane, tetrahydrofuran, acetonitrile, dimethylformamide, Examples thereof include dimethyl sulfoxide and acetamide, and these can be used alone or in combination of two or more. Preferred examples of the dispersion medium include water and a water-containing solvent, and water is particularly preferred.

<Composition of dispersion>
In the dispersion of the present invention, the (A) cellulose nanofiber is preferably contained in an amount of 0.1 to 10% by weight, more preferably 0.5 to 5.0% by weight, more preferably 1.0 to 3.0% by weight. (B) The dispersant is preferably contained in an amount of 0.1 to 50% by weight, more preferably 1 to 20% by weight, and more preferably 5 to 20% by weight based on the cellulose nanofibers (solid content weight). The content of the dispersion medium of the cellulose nanofiber dispersion is preferably 50 to 99.9% by weight, more preferably 60 to 99.5% by weight, and more preferably 70 to 99% by weight.

  The cellulose nanofiber dispersion of the present invention is preferably 0.01 to 0.4 parts by weight, more preferably 0.02 to 0.3 parts by weight, more preferably 1 part by weight of (A) cellulose nanofibers. It is about 0.03 to 0.25 parts by weight, most preferably about 0.05 to 0.2 parts by weight. If the amount of the dispersant is too much or too little, the cellulose nanofibers are liable to precipitate.

<(A) Cellulose nanofiber>
The cellulose nanofiber (A) used in the present invention has a fiber diameter of 100 nm or less, more preferably 80 nm or less, still more preferably 60 nm or less, particularly 40 nm or less. The cellulose nanofiber of the present invention has a fiber diameter that is very small and cellulose that is not sufficiently defibrated, and has an appearance close to a transparent solution when dispersed in water. It is not visually recognized that the nanofibers are dispersed, and a transparent dispersion liquid (when the concentration is low) or a transparent gel or an opaque gel (when the concentration is high) can be obtained. The “dispersion” of the present invention includes various forms such as an aqueous dispersion, an aqueous dispersion gel, and an aqueous dispersion paste.

It is known that the elastic modulus and strength of cellulose nanofibers composed of extended chain crystals reach 140 GPa and 3 GPa, respectively, which are equal to typical high-strength fibers and aramid fibers, and have higher elasticity than glass fibers. Moreover, the coefficient of linear thermal expansion is 1.0 × 10 ⁻⁷ / ° C., which is as low as quartz glass. The aqueous dispersion of cellulose nanofibers of the present invention is also useful as a composite reinforcing fiber because of its excellent nanofiber dispersibility.

<Method for producing dispersion>
The dispersion of the present invention is obtained by supplying cellulose, a dispersant, and a dispersion medium to a mechanical defibrating means, converting the cellulose into nanofibers by mechanical defibration, and obtaining a stable dispersion with the dispersant. It is done.
Examples of the mechanical defibrating means include a grinder, a kneader, a bead mill, a high-pressure homogenizer, an underwater counter collage, a high-speed rotary disperser, a beadless disperser, a high-speed agitation type medialess disperser, and preferably a high speed. A stirring type medialess disperser is most preferred.
In the medialess disperser, a cellulose nanofiber dispersion having a high purity and a small amount of impurities can be obtained.

The high-speed agitation type medialess disperser means a disperser that disperses using a shearing force without substantially using dispersive media (for example, beads, sand, balls, etc.).
The medialess disperser is not particularly limited. For example, DR-PILOT2000, ULTRA-TURRAX series, Dispax-Reactor series manufactured by IKA Corporation; K. Homomixer, T.W. K. Pipeline homomixer; Silverson high shear mixer; Taihei Yoko Co., Ltd. Milder, Cavitron; M Technic Co., Ltd. Claire mix: Mizuho Kogyo Co., Ltd. Homo mixer, pipeline mixer, Kotobuki Kogyo Co., Ltd. Product K-2 etc. are mentioned.

Among these, as the medialess disperser, a disperser including a rotor and a stator is preferable, and an example of such a high-speed stirring type medialess disperser includes a disperser manufactured by Kotobuki Industries Co., Ltd. The disperser includes a stator and a rotor that rotates inside the stator. A gap is formed between the stator and the rotor. By rotating the rotor and passing the mixed liquid between the stator and the rotor, a shearing force can be applied. The distance between the stator and the rotor is the shear clearance.
Further, the disperser is not limited to the above, and for example, a disperser in which a stator and a rotor are installed in multiple stages may be used.
As the medialess disperser of the present invention, it is preferable to use an in-line circulation type in which a mixed liquid circulates in the disperser from the viewpoint of performing the processing uniformly.

The shear rate in the medialess disperser exceeds 900,000 [1 / sec]. When the shear rate is 900,000 [1 / sec] or less, the cellulose is not defibrated.
The shear rate is preferably 2,000,000 [1 / sec] or less, preferably 1,500,000 [1 / sec] or less, and more preferably 1,200,000 [1 / sec] or less.
Further, the shear clearance of the medialess disperser is appropriately set according to the above shear rate, but is preferably 10 μm or more, more preferably 15 μm or more, and more preferably 20 μm or more from the viewpoint of obtaining the smallest possible cellulose nanofiber diameter. Further preferred. Further, from the viewpoint of keeping the rotational speed of the disperser at an appropriate value, the clearance is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 40 μm or less.
Further, the rotational peripheral speed of the medialess disperser is appropriately set according to the shear rate, but from the viewpoint of obtaining as small a cellulose nanofiber as possible, it is preferably 18 m / s or more, more preferably 20 m / s or more, 23 m / S or more is more preferable. Further, from the viewpoint of obtaining an optimum cellulose nanofiber diameter, the rotational peripheral speed is preferably 50 m / s or less, more preferably 40 m / s or less, and even more preferably 35 m / s or less. The rotational peripheral speed is the peripheral speed of the most advanced portion of the rotor.

Thus, the dispersion of cellulose nanofibers of the present invention is produced by treating a dispersion containing cellulose and a dispersant once to a plurality of times using the above-described high-speed stirring-type medialess disperser. can do.
The average fiber diameter of the cellulose nanofiber obtained by the treatment of the method of the present invention is about 10 to 100 nm, preferably about 10 to 40 nm, and most preferably about 15 to 25 nm. The nanofiber of the present invention has a long fiber length / fiber width (aspect ratio) and a good dispersion state, so it can be easily formed into a film or sheet in which nanofibers are entangled like a nonwoven fabric while maintaining strength. And can be suitably used as various materials. The nonwoven fabric in which the aqueous dispersion of cellulose nanofibers of the present invention is formed into a film / sheet is characterized by high transparency.

<(C) Resin component>
(C) As a resin component, it is a thermoplastic resin or a photocurable resin.
Among these, the thermoplastic resin refers to a resin that is melt-formed by heating. Specific examples thereof include polyethylene resin, polypropylene resin, polylactic acid resin, polyvinyl alcohol resin, polyamide resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate resin, and polyvinylidene chloride resin. , Ethylene vinyl alcohol resin, polyacrylonitrile resin, polyacetal resin, polyketone resin, and at least one selected from the group of cyclic polyolefin resins.
In the molding material of the present invention, when cellulose nanofibers are used as (A) nanofibers, heat resistance may not be sufficient. Therefore, (C) a polyethylene resin having a relatively low melting point as a resin component Among these, nylon 6 and the like are particularly preferably used among polypropylene resin, polylactic acid resin, polyvinyl alcohol resin, and polyamide resin.
In the present invention, when “(meth) acryloyloxyethyl phosphorylcholine (co) polymer” is used as the dispersant (B), the affinity between (A) cellulose nanofiber and (C) resin component is high. Since it improves further, the modeling material of the state in which both (A) component and (C) component were disperse | distributed uniformly can be obtained.

  Further, among the (C) resin components, as the photocurable resin, any of those used in the stereolithography can be used. For example, polyester acrylate, polyurethane acrylate, novolak type An epoxy resin, a bisphenol type epoxy resin or the like, to which an acetophenone-based, benzoyl-based, benzylketal-based or ketone-based photoinitiator is added.

<Ratio of each component in modeling material>
The blending ratio of each component in the molding material of the present invention is usually 0.5 to 20% by weight, preferably 1 to 10% by weight, and (B) the dispersant is 0.0005 to 10% in terms of solids (A) cellulose nanofibers. % By weight, preferably 0.001 to 5% by weight, and (C) resin component 70 to 99.4995% by weight, preferably 85 to 98.999% by weight [where (A) + (B) + (C) = 100% by weight] is there.
If the component (A) is less than 0.5% by weight, the strength and dimensional stability of the resulting molding material will be reduced, making it difficult to differentiate from the resin alone, whereas if it exceeds 20% by weight, the melt viscosity can be increased. The moldability of the modeling material is inferior, and the dispersibility of the cellulose nanofibers is inferior, resulting in a large amount of aggregates and difficulty in uniform dispersion.
Further, when the amount of (B) dispersant used is less than 0.0005% by weight, the dispersion of the dispersion of (A) cellulose nanofiber is deteriorated, and the compatibility with the resin is lowered, whereas it exceeds 10% by weight. And only a dispersing agent melt | dissolves in resin, and physical properties, such as a mechanical characteristic, fall.
Further, when the resin component (C) is less than 70% by weight, the moldability is poor, and a composite material cannot be obtained in the resin kneading step. On the other hand, when it exceeds 99.4995% by weight, it is difficult to differentiate from the resin alone.

<Preparation of modeling material>
The modeling material of the present invention is prepared using the dispersion obtained as described above and the (C) resin component.
In this case, in the method for producing the resin composition of the present invention, the dispersion mainly comprising (A) nanofibers and (B) dispersant is dried and kneaded with (C) the resin component. As a specific example in this case, a dispersion (emulsion or slurry) mainly composed of (A) nanofibers and (B) a dispersant is freeze-dried, dried under reduced pressure, heat-dried, or spray-dried, and then (C ) Kneading with the resin component.

  In this preparation method, first, a dispersion containing (A) cellulose nanofibers and (B) a dispersant is dried. This drying step is a step for removing the dispersion medium in the dispersion. Therefore, a well-known method can be employ | adopted according to the kind of dispersion medium in a dispersion.

As the means for removing the dispersion medium, an appropriate one is selected according to the type of the dispersion medium. For example, the dispersion may be naturally dried by simply allowing it to stand at room temperature, or may be a known drying method such as heat drying, vacuum drying (reduced pressure drying), freeze drying, or spray drying. Spray drying is performed by ejecting the dispersion from a nozzle to form fine droplets, and then heating and drying the droplets in convection air. In particular, when natural drying or heat drying is used, it is preferable from the viewpoint of drying efficiency that the mixture is cast into a film or a sheet by casting (casting) or the like and then dried. .
As the drying means, freeze-drying is preferable because the quality of the dried product obtained is not particularly deteriorated, and handling of the dried product is simple and easy.

Here, lyophilization is a technique in which the above dispersion is frozen and dried by reducing the pressure in the frozen state and sublimating the dispersion medium. The method of freezing the dispersion in lyophilization is not particularly limited. For example, a method of freezing the dispersion in a refrigerant, a method of freezing the dispersion in a low temperature atmosphere, and placing the dispersion under reduced pressure. There are methods such as freezing. Preferably, the dispersion is frozen in a refrigerant. The freezing temperature of the dispersion must be below the freezing point of the dispersion medium in the dispersion, preferably −50 ° C. or less, more preferably −80 ° C. or less.
In lyophilization, the dispersion medium in the frozen dispersion must be sublimated under reduced pressure. The pressure during decompression is preferably 100 Pa or less, and more preferably 10 Pa or less. When the pressure exceeds 100 Pa, the dispersion medium in the frozen dispersion may be melted.

  The form of the solid (dried product) of the dispersion obtained as described above is not particularly limited, and can be, for example, a three-dimensional shape, a film shape, a sheet shape, a powder shape, or a granular shape. The form of the solid can be adjusted by appropriately selecting a method for removing the dispersion medium from the mixture in the production method described above. For example, a film-like or sheet-like gel can be obtained by casting (casting) the dispersion and drying, and a powder or granular gel can be obtained by spray-drying the dispersion. You can get a body. Also, a three-dimensional dried product can be produced by pouring the dispersion into a mold having an arbitrary shape and drying it.

Subsequently, the dried product of the dispersion and the resin component (C) are melt-kneaded.
This melt-kneading is a step of combining the dried dispersion obtained as described above and the resin component (C) while melt-kneading.
As the melt-kneading apparatus, a known kneading apparatus such as a single-screw extruder, a twin-screw extruder, a twin-screw kneader, a kneader, a Banbury mixer, a reciprocating kneader (BUSS KNEADER), a roll kneader, or the like can be used. . Of these, a single screw extruder, a twin screw extruder, a twin screw kneader, a Banbury mixer, and a reciprocating kneader are preferable in consideration of productivity and workability. When selecting a melt-kneading apparatus, it is more effective to select a device having a high hermeticity inside the kneading machine to produce a resin composition that has a higher dispersibility and is substantially free of coarse aggregates. be able to.
Specific examples of the melt kneading method include the following methods. In other words, the dried product of the dispersion and the resin component (C) are uniformly mixed with a tumbler mixer, super mixer, super floater, Henschel mixer, etc., and they are put into a single screw extruder or a twin screw extruder. Examples thereof include a method of melt-kneading, or a method of melt-kneading the dried product and the resin component (C) with a single screw extruder or a twin screw extruder. In addition, in order to remove the water | moisture content and other volatile matter which generate | occur | produce in a melt-kneading process, you may use opening of a vent and deaeration equipment.

  The temperature at the time of melt kneading in the preparation of the modeling material of the present invention is appropriately set according to the melting temperature of the resin component (C), and is, for example, in the range of 70 to 220 ° C. In particular, when an olefin resin is used as the resin component (C), the kneading temperature is in the range of 70 ° C to 220 ° C, preferably in the range of 80 ° C to 220 ° C, and more preferably in the range of 85 ° C to 220 ° C. The range of 90 ° C. to 200 ° C. is preferable. Below this range, the resin to be kneaded does not melt and is virtually impossible to manufacture. When exceeding this range, the (A) cellulose nanofibers used for production are damaged by heat, resulting in molecular chain breakage, oxidative degradation, modification, etc., not only reducing mechanical properties but also unpleasant odor. It leads to generation and discoloration.

  The melt kneading time in this case is preferably longer in terms of ensuring dispersibility with (A) cellulose nanofibers, (B) dispersant and (C) resin component, but considering the balance with productivity. Set as appropriate. For example, when a batch-type kneader such as a Banbury mixer is used, if it is within the range of 1 to 100 minutes, both plant fiber modification and productivity can be achieved, but productivity must be taken into consideration. For example, the manufacturing can be performed even in a longer time. Further, for example, when a continuous kneader such as a single screw extruder, a twin screw extruder, a reciprocating kneader (BUSS KNEADER) is used, if the residence time is within a range of 1 to 20 minutes, Dispersibility and productivity can be achieved at the same time. However, if productivity is not taken into consideration, manufacture is possible even if the time is longer or the number of passes of the kneader is increased.

<Other additives>
In addition, in the modeling material of the present invention, conventionally known various additives may be contained depending on the use, for example, hydrolysis inhibitor, colorant, flame retardant, ultraviolet absorber, antistatic agent, Examples thereof include a lubricant, a release agent, an antifoaming agent, a leveling agent, a light stabilizer (eg, hindered amine), an antioxidant, an inorganic filler, and an organic filler.

<Manufacturing method of modeling material>
The form of the modeling material of the present invention is not limited as long as it can be attached to a 3D printer. However, for example, when used for a hot melt lamination type 3D printer, it is formed into a continuous line. In this case, a linear body having a diameter of 1.75 mm to 3.00 mm, that is, a molded body having a so-called monofilament yarn shape is preferable. A formed body having a monofilament yarn shape which is continuous linear is preferably wound around a bobbin or can be made into a compact shape by skeining.
Such a modeling material in the present invention can be obtained by the following method. That is, the modeling material (resin composition) prepared as described above is discharged from a melt extruder, cooled and solidified in a liquid bath such as air or water, and a continuous linear monofilament yarn is obtained. Can be manufactured.

In addition, in order to manufacture the modeling material of the present invention, the resin composition containing the components (A) to (C) as main components may be melt-extruded as it is. (B) A masterbatch in which the dispersant is kneaded into the (C) resin component is prepared, and the masterbatch and the (C) resin component such as virgin polylactic acid are mixed at a predetermined ratio, and melt extruded. Cellulose nanofibers can be more uniformly dispersed in the resin component (C).
The melting temperature of the (C) resin component such as polylactic acid in the melt extruder during melt extrusion is 20 than the melting point of the (C) resin component (generally, the melting point is 150 ° C. to 180 ° C. in the case of polylactic acid). By setting the temperature to be higher than C, the resin component (C) is melted and extruded. The resin component (and nanofibers) (C) that has been extruded into a continuous monofilament thread is cooled and solidified in a liquid bath. The cooling / solidification temperature is preferably set within the range of -50 to + 20 ° C than the glass transition temperature of the resin component (generally, the glass transition temperature of polylactic acid is 55 to 60 ° C). .

Water, ethylene glycol, polyethylene glycol, glycerin, silicone, etc. can be used as the liquid used for cooling and solidification, but since there is no need for the liquid bath to be hot, water with good workability and resistance to environmental pollution is required. Most preferred. Water is most preferred.
The cooled and solidified monofilament yarn may be wound as it is after drying. Or you may extend | stretch in the atmosphere of temperature 20-80 degreeC as needed. When extending | stretching, it can carry out by one step | paragraph or multiple steps | paragraphs or more.
The modeling material of the present invention is applied as a modeling material for a 3D printer, and a desired modeled object can be obtained based on a design drawing on a computer.
In addition, although the modeling material of this invention demonstrated mainly the case of the 3D printer of a hot melt lamination system, it is applicable also to material jetting, binder jetting, powder sintering lamination molding, optical modeling, etc. in addition to this.

Hereinafter, the present invention will be described with reference to examples.
Examples 1-3, Comparative Examples 1-2
K-2 manufactured by Kotobuki Kogyo Co., Ltd. is used as a medialess disperser, and a slurry in which purified water as a dispersion medium, cellulose, which is a raw material of cellulose nanofiber, and a dispersing agent are dispersed is introduced into the medialess disperser. Then, it was circulated at a rotational peripheral speed of 30 m / s, and the dispersion of cellulose was promoted by shearing to obtain cellulose nanofibers with stable dispersion.
That is, using the above apparatus, water dispersion containing 0.1% by weight of cellulose nanofiber raw material (BiNFi-s, manufactured by Sugino Machine) and 0.04% by weight of methacryloyloxyethyl phosphorylcholine (co) polymer as a dispersant. Repeat the medialess dispersion process 5 times for the liquid to prepare a cellulose nanofiber dispersion, then transfer to a freeze-drying container and freeze at -80 ° C, then freeze-dryer (manufactured by Tokyo Rika Kikai Co., Ltd.) FD-1) and lyophilized. After freeze-drying, it was powdered using a pulverizer.
The powder obtained above was blended at 1, 5, 10% by weight with polylactic acid resin (manufactured by Nature Works, Ingeo Biopolymer 3001D), and a twin-screw kneading extruder (Plastic Engineering Research Co., Ltd.) Cellulose nanofibers and resin were compounded with “BT-30” (L / D = 30) manufactured by Tosho Co., Ltd., and a strand having a diameter of 1.75 mm was drawn using a strand die to obtain a monofilament for a 3D printer. The filament was pelletized with a strand cutter to a length of 2 mm, and a test piece for evaluating mechanical properties was injection molded.
Using this injection-molded test piece, mechanical properties (tensile strength, tensile breaking elongation, and tensile modulus) were measured by Shimadzu Autograph (AG-X PLUS). Further, the dimension in the length direction of the test piece molded product was measured with a micrometer, and the shrinkage rate was obtained based on the mold cavity dimension. Furthermore, the fluidity of the composite material was measured using a Shimadzu flow tester CFT-5000 (manufactured by Shimadzu Corporation) at a barrel temperature of 200 ° C. and a measurement load of 700 N.
In addition, as the effect of shape stability by CNF, the reference of the top part of the thread of the thread part of the M16 hexagon bolt (Fig. 1) that was actually manufactured using a hot melt lamination type 3D printer (Leapfrog, Creatr dual) The amount of deviation from the line was measured with a universal projector (V-12, manufactured by Nikon Corporation).
The results are shown in Table 1.

From the comparison of Examples 1 to 3 and Comparative Examples 1 and 2, when cellulose nanofibers are added, the fluidity decreases according to the amount added, and the tensile strength and the tensile elastic modulus are improved. And the shrinkage rate of the injection molded product is reduced. Furthermore, the thread misalignment decreases with increasing cellulose nanofiber addition. This is considered to be a synergistic effect that the shrinkage rate of the injection-molded product is reduced and the fluidity of the material is low.
Thus, by adding cellulose nanofibers to the modeling material for 3D printer, the strength and elastic modulus are increased, and the shape accuracy as a molded product is improved. Further, using the 3D printer modeling material obtained in the above example, the appearance of a 3D model to which a 3D printer (Leapfrog, Creatr dual) was applied was observed. As a result, the shape on design could be reproduced more accurately as a modeled object, and the modeled object was excellent in surface smoothness, transparency and dyeability.

The modeling material of the present invention is suitable for producing a modeled article having high functionality using a 3D printer such as a hot melt lamination method.

Claims (9)

  A modeling material for a 3D printer, comprising (A) nanofibers, (B) a dispersant, and (C) a resin component composed of a thermoplastic resin or a photocurable resin as a main component.   (A) The modeling material according to claim 1, wherein the nanofiber is a cellulose nanofiber.   (A) The modeling material according to claim 2, wherein the cellulose nanofibers have an average fiber diameter of 10 to 100 nm.   The modeling material in any one of Claims 1-3 whose (B) dispersing agent has a (meth) acryloyloxyethyl phosphorylcholine (co) polymer as a main component.   (B) The (meth) acryloyloxyethyl phosphorylcholine (co) polymer constituting the dispersant is selected from the group of polymethacryloyloxyethyl phosphorylcholine, polybutyl methacrylate / methacryloyloxyethyl phosphorylcholine, and poly (stearyl methacrylate / methacryloyloxyethyl phosphorylcholine). The modeling material according to claim 4, which is at least one selected.   The thermoplastic resin is polyethylene resin, polypropylene resin, polylactic acid resin, polyvinyl alcohol resin, polyamide resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate resin, polyvinylidene chloride resin, The modeling material in any one of Claims 1-5 which is at least 1 sort (s) chosen from the group of ethylene vinyl alcohol resin, polyacrylonitrile resin, polyacetal resin, polyketone resin, and cyclic polyolefin resin.   In terms of solids, in terms of solids, (A) nanofibers are 0.5 to 20% by weight, (B) the dispersant is 0.0005 to 10% by weight, and (C) the resin component is 70 to 99.495% by weight [ However, the modeling material in any one of Claims 1-6 which is (A) + (B) + (C) = 100 weight%].   A method for producing a modeling material for a 3D printer, wherein the modeling material according to claim 1 is melt-extruded and then cooled and solidified in a liquid bath to form a monofilament yarn. A three-dimensional structure obtained by applying a 3D printer using the modeling material according to claim 1.