JP7147348B2 - Three-dimensional modeling powder, three-dimensional model manufacturing apparatus, three-dimensional model manufacturing method, and powder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a three-dimensional modeling powder, a three-dimensional article manufacturing apparatus, a three-dimensional article manufacturing method, and powder.

A method for manufacturing three-dimensional objects such as prototypes or final products by selectively melting and sintering resin powder is known. For example, in the powder bed fusion (PBF) method, by irradiating a thin layer of resin powder with a laser, the resin powder is selectively melted and sintered, and the resulting layers are laminated repeatedly. shape.

The PBF method includes the SLS (Selective Laser Sintering) method in which the resin powder is selectively irradiated with a laser for modeling, and the SMS (Selective Mask Sintering) method in which the resin powder is partially masked and the laser is irradiated in a plane. methods, etc. In addition, as an application of the PBF method, MJF (Multi Jet Fusion) or HSS (High Speed Fusion), in which a liquid containing a heat absorbing agent is dropped onto the resin powder and the resin powder is selectively melted by heating with infrared light, Sintering method, BJ (Binder Jetting) method, etc. are also known.

When modeling using resin powder, the internal stress between the molding layers is kept low and relaxed (relaxed). When resin powder adjusted to a temperature near the softening point is irradiated with a laser, the resin powder is heated to a temperature equal to or higher than the softening point and melts.

As a resin powder, for example, Patent Literature 1 discloses a semi-aromatic polyamide resin composition used in a thermal melting lamination method such as laser irradiation.

However, in the prior art, a part of the laser used for modeling may be reflected by the resin powder, resulting in poor modeling, and improvement in modeling accuracy is required. When an absorbing material or the like is added in order to improve accuracy and resolution, the resin powder melts in areas other than the areas to be melted by laser irradiation, resulting in excessive melting. In addition, repeated formation of layers of the resin powder deteriorates the mechanical performance, and therefore, improvement in the tensile strength of the obtained three-dimensional object is required.

An object of the present invention is to provide a three-dimensional modeling powder that has good modeling accuracy, can suppress excessive melting, provides good surface properties, and provides a three-dimensional article with good tensile strength.

In order to solve the above problems, the three-dimensional modeling powder of the present invention contains a resin and a black dye, and is a three-dimensional modeling powder that forms a three-dimensional object by being irradiated with electromagnetic rays, and has a cumulative volume of 50% The particle diameter is 5 μm or more and 100 μm or less, the volume average particle diameter/number average particle diameter is 2.50 or less, the reflectance for electromagnetic rays is 10% or less, and the reflectance is obtained by the following measurement. It is characterized by
[measurement]
Using an infrared spectrometer 680-IR (manufactured by VARIAN), the value at a wavelength of 10.6 μm is taken as the reflectance.

According to the present invention, it is possible to provide a three-dimensional modeling powder that has good modeling accuracy, can suppress excessive melting, obtains good surface properties, and gives a three-dimensional object with good tensile strength.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows an example of the manufacturing apparatus of the three-dimensional molded article which concerns on this invention. It is a conceptual diagram for demonstrating an example of the manufacturing method of the three-dimensional molded article which concerns on this invention. It is a conceptual diagram for demonstrating an example of the manufacturing method of the three-dimensional molded article which concerns on this invention. It is a SEM image which shows an example of the powder for three-dimensional modeling. It is a schematic perspective view which shows an example of a cylindrical body. FIG. 6 is a side view of the cylinder of FIG. 5; FIG. 4 is a side view showing an example of a cylindrical body having no vertices at its ends; FIG. 10 is a side view showing another example of a cylindrical body having no vertices at its ends; FIG. 10 is a side view showing another example of a cylindrical body having no vertices at its ends; FIG. 10 is a side view showing another example of a cylindrical body having no vertices at its ends; FIG. 10 is a side view showing another example of a cylindrical body having no vertices at its ends; FIG. 10 is a side view showing another example of a cylindrical body having no vertices at its ends; FIG. 10 is a side view showing another example of a cylindrical body having no vertices at its ends;

Hereinafter, the three-dimensional modeling powder, the three-dimensional article manufacturing apparatus, the three-dimensional article manufacturing method, and the powder according to the present invention will be described with reference to the drawings. In addition, the present invention is not limited to the embodiments shown below, and can be changed within the scope of those skilled in the art, such as other embodiments, additions, modifications, deletions, etc. is also included in the scope of the present invention as long as the functions and effects of the present invention are exhibited.

(Powder and powder for stereolithography)
The three-dimensional modeling powder of the present invention contains a resin, is a three-dimensional modeling powder that forms a three-dimensional object by irradiation with electromagnetic rays, has a 50% cumulative volume particle size of 5 μm or more and 100 μm or less, and has a volume average particle size of The diameter/number average particle diameter is 2.50 or less, and the reflectance to the electromagnetic radiation is 10% or less. Further, if necessary, the three-dimensional modeling powder may contain other components, and any other components may be contained inside or outside the resin.
In the following description, the three-dimensional modeling powder may be simply referred to as resin powder.

The powder of the present invention contains a resin, is a powder that hardens when irradiated with electromagnetic rays, has a 50% cumulative volume particle size of 5 μm or more and 100 μm or less, and a volume average particle size/number average particle size of 2.50 or less. and the reflectance for the electromagnetic rays is 10% or less.
The powder for stereolithography of the present invention is included in the powder of the present invention, and unless otherwise specified, the description of the powder for stereolithography of the present invention also applies to the powder of the present invention.

In the conventional technology, a part of the laser used for molding is reflected by the resin powder, resulting in defective molding. Therefore, it is conceivable to add an absorbing material such as carbon black. Since the heat is transferred to the laser, the surface temperature of the modeling layer rises, and heat is supplied excessively to the modeling layer that the laser hits, making it difficult to control the laser output. Due to this, the melting spreads to the periphery of the melting target portion, and excessive melting occurs in which the resin powder melts in areas other than the target portion. If excessive melting occurs, the molding accuracy is degraded, and good surface properties cannot be obtained. In addition, repeated formation of layers of the resin powder deteriorates the mechanical performance, and therefore, improvement in the tensile strength of the obtained three-dimensional object is required. If there are many effects of over-molding, the function as a modeled object is not satisfied, so it is necessary to interrupt the molding in the middle, and the finished product cannot be obtained.

In this embodiment, the shape of the resin particles in the resin powder, the components contained in the resin powder, and the like are controlled to control the reflectance with respect to electromagnetic rays, thereby improving the modeling accuracy. As a result, good precision can be obtained, the occurrence of excessive melting can be suppressed, and even a modeled object having small holes can be modeled without filling the holes. Furthermore, it is possible to prevent the occurrence of additional processing due to failure to obtain the desired modeled object. In addition, a model having a smooth surface can be obtained, the occurrence of orange peel can be suppressed, and good resolution can be obtained.

<Resin>
A thermoplastic resin is preferable as the resin component. A thermoplastic resin is a resin that plasticizes and melts when heat is applied. The thermoplastic resin is preferably a crystalline resin. A crystalline resin is a resin from which a melting point peak is detected in a measurement conforming to ISO3146 (plastic transition temperature measurement method, JIS K7121).

Examples of the resin component in the resin powder include polyolefin, polyamide, polyester, polyether, polyphenylene sulfide, liquid crystal polymer (LCP), polyacetal (POM: Polyoxymethylene, melting point: 175°C), polyimide, and fluorine resin. be done. Resin may be used individually by 1 type, and may use 2 or more types together.

Examples of polyolefin include polyethylene and polypropylene (PP, melting point: 180°C).

Polyamides include polyamide 410 (PA410), polyamide 6 (PA6), polyamide 66 (PA66, melting point: 265°C), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 11 (PA11), and polyamide 12 (PA12 ); and semi-aromatic polyamides such as polyamide 4T (PA4T), polyamide MXD6 (PAMXD6), polyamide 6T (PA6T), polyamide 9T (PA9T, melting point: 300° C.), and polyamide 10T (PA10T). . PA9T, also called polynonamethylene terephthalamide, is composed of a 9-carbon diamine and a terephthalic acid monomer and is semi-aromatic with the aromatic on the carboxylic acid side. Polyamides also include aramids formed from p-phenylenediamine and terephthalic acid monomers as wholly aromatic, in which not only the carboxylic acid side but also the diamine side is aromatic.

Examples of polyester include polyethylene terephthalate (PET, melting point: 260°C), polybutadiene terephthalate (PBT, melting point: 218°C), and polylactic acid (PLA). In order to impart heat resistance, a polyester containing aromatics partially containing terephthalic acid or isophthalic acid is also preferably used in the present invention.

Polyethers include polyetheretherketone (PEEK, melting point: 343° C.), polyetherketone (PEK), polyetherketoneketone (PEKK), polyaryletherketone (PAEK), polyetheretherketoneketone (PEEKK), and polyarylketones such as polyetherketoneetherketoneketone (PEKEKK). Polyethersulfone can also be used as the resin component.

The thermoplastic resin may have two melting peaks, for example PA9T. A thermoplastic resin having two melting point peaks melts completely at a temperature equal to or higher than the melting point peak on the high temperature side. The resin powder preferably contains one or more thermoplastic resins having a melting point of 100° C. or higher.

In order to prevent warping of the shaped object, the temperature range (temperature window) for crystal layer change, ie, the difference between the melting start temperature and the recrystallization point during cooling, is preferably larger than 3°C. More preferably, the temperature is 5° C. or more, since a high-definition shaped object can be formed. Further, by selecting a resin having a decomposition temperature higher than the laser heating temperature and other components, it is possible to suppress smoke generation due to laser irradiation.

<Other ingredients>
Examples of other components in the resin powder include additives such as antireflection agents, antidegradants, fluidizers, reinforcing agents, flame retardants, plasticizers and crystal nucleating agents, and amorphous resins. Other components may be used by mixing with the particles in the resin powder, or may be used by coating the surfaces of the particles. When the resin powder contains other components, the other components may be used singly or in combination of two or more.

<<Antireflection agent>>
Examples of the antireflection agent include black pigments, black dyes, and the like, and at least one or more selected from black pigments and black dyes is preferable.
Examples of black pigments include carbon black, graphite, black iron oxide, titanium black, phthalocyanine, and azo pigments. The dispersed particle size is preferably 0.01 to 50 μm, and more preferably 0.01 to 10 μm because the smaller the particle size, the better the dispersibility.
As black dyes, azo dyes, aniline black, and nigrosine black dyes such as azine dyes and squalium dyes are preferably used.

The content (total amount) of the antireflection agent is preferably 0.01% by mass or more and 7.5% by mass or less based on the resin, and is 0.05% by mass or more and 1.0% by mass or less. is more preferable, and 0.5% by mass or less is even more preferable.

<< Anti-degradation agent >>
In order to maintain the thermal stability of molecules and suppress resin deterioration such as cross-linking or decomposition, the resin powder may contain an anti-degradation agent. Examples of deterioration inhibitors include metal chelating agents, ultraviolet absorbers, polymerization inhibitors, antioxidants, and the like.

Examples of metal chelating agents include hydrazide-based, phosphate, and phosphite-based compounds.
Triazine-based compounds are exemplified as UV absorbers.
Copper acetate etc. are illustrated as a polymerization inhibitor.

Antioxidants are exemplified by hindered phenol-based, phosphorus-based and sulfur-based compounds.
Various additives such as radical scavengers are used as hindered phenol-based antioxidants. Specific examples of hindered phenol antioxidants include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2-tert-butyl-6-(3′-tert-butyl-5′-methyl-2′-hydroxybenzyl)-4-methylphenyl acrylate, 2,6-di-tert-butyl-4-(N ,N-dimethylaminomethyl)phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, 2,2′-methylenebis(4-methyl-6-tert-butylphenol), 2,2′- methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2, 2′-dimethylene-bis(6-α-methyl-benzyl-p-cresol), 2,2′-ethylidene-bis(4,6-di-tert-butylphenol), 2,2′-butylidene-bis(4 -methyl-6-tert-butylphenol), 4,4′-butylidenebis(3-methyl-6-tert-butylphenol), triethylene glycol-N-bis-3-(3-tert-butyl-4-hydroxy-5 -methylphenyl)propionate, 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis[2-tert-butyl-4-methyl 6-( 3-tert-butyl-5-methyl-2-hydroxybenzyl)phenyl]terephthalate, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]- 1,1,-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 4,4′-thiobis(6-tert-butyl-m-cresol), 4,4′- thiobis(3-methyl-6-tert-butylphenol), 2,2′-thiobis(4-methyl-6-tert-butylphenol), bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, 4,4′-di-thiobis(2,6-di-tert-butylphenol), 4,4′-tri-thiobis(2,6-di-tert-butylphenol) nol), 2,2-thiodiethylenebis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy -3,5-di-tert-butylanilino)-1,3,5-triazine, N,N′-hexamethylenebis-(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), N, N′-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-tert-butyl-4-hydroxy phenyl)isocyanurate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,3,5-tris-2[3(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanurate, tetrakis[methylene-3-(3,5-di-tert -butyl-4-hydroxyphenyl)propionate]methane, triethylene glycol-N-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, triethylene glycol-N-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl)acetate, 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)acetyloxy}-1 ,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, tetrakis[methylene-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]methane , 1,3,5-trimethyl-2,4,6-tris(3-tert-butyl-4-hydroxy-5-methylbenzyl)benzene, and tris(3-tert-butyl-4-hydroxy-5-methyl benzyl) isocyanurate and the like.

Among hindered phenolic antioxidants, tetrakis[methylene-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]methane, octadecyl-3-(3,5-di-tert- Butyl-4-hydroxyphenyl)propionate and 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2 ,4,8,10-tetraoxaspiro[5,5]undecane and tetrakis[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane have high temperature stability. 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8, More preferred are 10-tetraoxaspiro[5,5]undecane and tetrakis[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane. The hindered phenol-based antioxidants may be used singly or in combination of two or more.

Examples of phosphorus-based antioxidants include phosphorous acid, phosphoric acid, phosphonous acid, and phosphonic acid; phosphite compounds, phosphate compounds, phosphonite compounds, esters thereof such as phosphonate compounds; and tertiary phosphines. be done. Phosphorus-based antidegradation agents may be used singly or in combination of two or more.

Phosphite compounds include triphenylphosphite, tris(nonylphenyl)phosphite, tridecylphosphite, trioctylphosphite, trioctadecylphosphite, didecylmonophenylphosphite, dioctylmonophenylphosphite, diisopropylmonophenyl Phosphite, monobutyldiphenylphosphite, monodecyldiphenylphosphite, monooctyldiphenylphosphite, tris(diethylphenyl)phosphite, tris(di-iso-propylphenyl)phosphite, tris(di-n-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tris(2,6-di-tert-butylphenyl)phosphite, distearylpentaerythritol diphosphite, bis(2,4-di -tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-ethyl Phenyl)pentaerythritol diphosphite, bis{2,4-bis(1-methyl-1-phenylethyl)phenyl}pentaerythritol diphosphite, phenylbisphenol A pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite Examples include phosphite and dicyclohexylpentaerythritol diphosphite.

Among these phosphite compounds, distearylpentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methyl Phenyl)pentaerythritol diphosphite and bis{2,4-bis(1-methyl-1-phenylethyl)phenyl}pentaerythritol diphosphite are preferred in terms of high temperature stability.

These phosphite compounds may be commercially available products.
Commercial products of distearylpentaerythritol diphosphite include ADEKA STAB PEP-8 (manufactured by ADEKA) and JPP681S (manufactured by Johoku Kagaku Kogyo Co., Ltd.). Commercial products of bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite include Adekastab PEP-24G (manufactured by ADEKA), Alkanox P-24 (manufactured by Great Lakes), Ultranox P626 (GE Specialty Chemicals), Doverphos S-9432 (manufactured by Dover Chemicals), and Irgaofos 126 and 126FF (manufactured by CIBA SPECIALTY CHEMICALS).

Commercial products of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite include ADEKA STAB PEP-36 (manufactured by ADEKA).

Commercial products of bis{2,4-bis(1-methyl-1-phenylethyl)phenyl}pentaerythritol diphosphite include Adekastab PEP-45 (manufactured by ADEKA) and Doverphos S-9228 (manufactured by Dover Chemical). ) and the like are exemplified.

Examples of other phosphite compounds include compounds that react with dihydric phenols and have a cyclic structure.
Compounds that react with dihydric phenols and have a cyclic structure include 2,2′-methylenebis(4,6-di-tert-butylphenyl)(2,4-di-tert-butylphenyl)phosphite, 2 ,2′-methylenebis(4,6-di-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite and 2,2-methylenebis(4,6-di-tert-butylphenyl) Examples include octyl phosphite.

Phosphate compounds include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorthoxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, Examples include octadecyl phosphate and diisopropyl phosphate. Among these phosphate compounds, triphenyl phosphate, octadecyl phosphate, and trimethyl phosphate are preferred in terms of high temperature stability.

Phosphonite compounds include tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylenedi Phosphonite, Tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylenediphosphonite, Tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite , tetrakis(2,6-di-tert-butylphenyl)-4,3′-biphenylenediphosphonite, tetrakis(2,6-di-tert-butylphenyl)-3,3′-biphenylenediphosphonite, bis (2,4-di-tert-butylphenyl)-4-phenyl-phenylphosphonite, bis(2,4-di-tert-butylphenyl)-3-phenyl-phenylphosphonite, bis(2,6-di -n-butylphenyl)-3-phenyl-phenylphosphonite, bis(2,6-di-tert-butylphenyl)-4-phenyl-phenylphosphonite, and bis(2,6-di-tert-butylphenyl )-3-phenyl-phenylphosphonite and the like.

Among the phosphonite compounds, tetrakis(di-tert-butylphenyl)-biphenylenediphosphonite and bis(di-tert-butylphenyl)-phenyl-phenylphosphonite are preferred in that they can be used together with a phosphite compound. Also preferred are tetrakis(2,4-di-tert-butylphenyl)-biphenylenediphosphonite and bis(2,4-di-tert-butylphenyl)-phenyl-phenylphosphonite.

Examples of phosphonate compounds include dimethyl benzenephosphonate, diethyl benzenephosphonate, and dipropyl benzenephosphonate.

Tertiary phosphines include triethylphosphine, tripropylphosphine, tributylphosphine, trioctylphosphine, triamylphosphine, dimethylphenylphosphine, dibutylphenylphosphine, diphenylmethylphosphine, diphenyloctylphosphine, triphenylphosphine, and tri-p-tolyl. Examples include phosphine, trinaphthylphosphine, and diphenylbenzylphosphine. Among tertiary phosphines, triphenylphosphine is preferable in terms of long-term stability at high temperatures.

When two or more types of anti-deterioration agents are used in combination, there is also a combination in which a more remarkable effect can be obtained. For example, when a hindered phenol and a phosphorus-based antioxidant are used in combination as an anti-degradation agent, there is a complementary effect of improving stability, so that an effect of improving long-term thermal stability can be obtained.

The content of the anti-degradation agent is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, relative to the total amount of the resin powder, from the viewpoint of preventing long-term deterioration. Preferably, it is more preferably 0.1% by mass or more and 5% by mass or less. When two or more antideterioration agents are used in combination, the preferred range of the content of each antidegradation agent is the same as the above range. If the content is within the above range, the effect of preventing the thermal deterioration of the resin is sufficiently obtained, the physical properties of the molded object when the resin powder used for molding is recycled, and the discoloration of the resin powder due to heat is improved. A preventive effect is also obtained.

<< Fluidizing agent >>
The fluidizing agent is not particularly limited, but spherical particles made of an inorganic material are exemplified. The volume average particle diameter of the spherical particles made of inorganic material is not particularly limited, but is preferably less than 10 μm. The content of the fluidizing agent may be an amount sufficient to cover the particle surfaces, and is preferably 0.1% by mass or more and 10% by mass or less based on the total amount of the resin powder.

Inorganic materials for spherical particles include silica, alumina, titania, zinc oxide, magnesium oxide, tin oxide, iron oxide, copper oxide, hydrated silica, silica whose surface is modified with a silane coupling agent, and magnesium silicate. are exemplified. Among these, silica, titania, hydrated silica, and silica whose surface is modified with a silane coupling agent are preferable from the viewpoint of the effect of improving fluidity, and from the viewpoint of cost, the surface is made hydrophobic with a silane coupling agent. Sexually modified silica is more preferred.

<< Strengthening agent >>
Examples of reinforcing agents include fiber fillers, bead fillers, glass fillers described in International Publication No. 2008/057844, glass beads, carbon fibers, aluminum balls, and the like, from the viewpoint of strength improvement. A reinforcing agent may be used individually by 1 type, and may use 2 or more types together.

Examples of fiber fillers include, but are not limited to, carbon fibers, inorganic glass fibers, and metal fibers. Examples of bead fillers include, but are not limited to, carbon beads, inorganic glass beads, and metal beads.

Since the thermal conductivity of the fiber filler or bead filler is higher than that of the resin powder, when the surface of the resin powder is irradiated with a laser in SLS modeling, the heat of the irradiated portion diffuses to the outside of the laser irradiated portion. For this reason, if a fiber filler or bead filler is mixed with a resin powder that does not have sharp-melt properties, the resin powder outside the laser-irradiated area will be heated by thermal diffusion and will melt excessively, resulting in poor molding accuracy. becomes lower. However, when a resin powder containing a crystalline thermoplastic resin and having a sharp melting property is mixed with a fiber filler or a bead filler, even if the resin powder outside the laser irradiation area is heated by thermal diffusion, Since it becomes difficult to melt, high molding accuracy can be maintained.

The average fiber diameter of the fiber filler is preferably 1 μm or more and 30 μm or less, and the average fiber length of the fiber filler is preferably 30 μm or more and 500 μm or less. By using a fiber filler with an average fiber diameter and an average fiber length in the above ranges, the strength of the modeled article is improved, and the surface roughness of the modeled article is the same as that of a modeled article that does not contain fiber filler. can be maintained to some extent.

The circularity of the bead filler is preferably 0.8 or more and 1.0 or less, and the volume average particle diameter of the bead filler is preferably 10 μm or more and 200 μm or less. The degree of circularity is obtained by the following formula, where S is the area (the number of pixels indicating the bead filler when the bead filler is imaged) and L is the peripheral length.
Circularity = 4πS/L ² (formula)

The volume average particle diameter can be measured, for example, using a particle size distribution analyzer (microtrac MT3300EXII manufactured by Microtrac Bell).

The content of the fiber filler is preferably 5% by mass or more and 60% by mass or less with respect to the total amount of the resin powder. When the content is 5% by mass or more, the strength of the shaped article is improved, and when it is 60% by mass or less, the moldability is improved.

The content of the bead filler is preferably 5% by mass or more and 60% by mass or less with respect to the total amount of the resin powder. When the content is 5% by mass or more, the strength of the shaped article is improved, and when it is 60% by mass or less, the moldability is improved.

<<flame retardant>>
Examples of flame retardants include halogen-based, phosphorus-based, inorganic hydrated metal compound-based, nitrogen-based, and silicone-based flame retardants. Various flame retardants, such as those for construction, vehicle, or ship outfitting, may be used in the resin powder. When two or more flame retardants are used in combination, flame retardancy is improved by combining halogen-based and inorganic hydrated metal compound-based.

The resin powder may also contain fibrous substances such as glass fibers, carbon fibers, or aramid fibers; or inorganic reinforcing agents such as talc, mica, or inorganic layered silicates such as montmorillonite. According to such an embodiment, it is possible to achieve both enhancement of physical properties and enhancement of flame retardancy.

The flame retardancy of resin powder can be evaluated by, for example, JIS K6911, JIS L1091 (ISO6925), JIS C3005, exothermic test (cone calorimeter), and the like.

The content of the flame retardant is preferably 1% by mass or more and 50% by mass or less with respect to the total amount of the resin powder, and more preferably 10% by mass or more and 30% by mass or less from the viewpoint of further enhancing flame retardancy. Sufficient flame retardancy is obtained as content is 1 mass % or more. When the content is 50% by mass or less, changes in the melt-solidification characteristics of the resin powder are suppressed, and deterioration in modeling accuracy and deterioration of the physical properties of the model can be prevented.

<Method for producing three-dimensional modeling powder>
<< Grinding >>
The resin powder can be obtained, for example, by pulverizing a pellet-shaped resin composition containing the above resin with a pulverizer, and classifying or filtering particles other than the specified particle size with a filter. When pulverizing using the brittleness of the resin, the environment during pulverization is below the brittle temperature of the resin, preferably below room temperature, more preferably below 0°C, and even more preferably below -25°C. and more preferably −100° C. or lower.

In order to improve the fluidity of the resin particles, it is preferable to remove, for example, particles of 80 μm or more and particles of 25 μm or less in the classification operation. The resin powder is preferably dry to such an extent that it does not affect modeling. Therefore, resin powder dried with a vacuum dryer or silica gel may be used for modeling.

<<Crystallinity Control>>
By controlling the crystal size and crystal orientation of the crystalline resin in the resin powder, it is possible to reduce errors due to recoating in the modeling process under a high-temperature environment. Methods for controlling the crystal size and crystal orientation include heat treatment, stretching, treatment using ultrasonic waves, and methods using external stimuli such as treatment using an external electric field; methods using a crystal nucleating agent; Examples include a method that does not use an external stimulus, such as a method of increasing crystallinity by dissolving and slowly volatilizing the solvent.

An example of the heat treatment is an annealing treatment in which the resin is heated to a temperature equal to or higher than the glass transition temperature to increase the crystallinity. In order to further improve the crystallinity, the resin to which a crystal nucleating agent is added may be subjected to an annealing treatment. An example of the annealing treatment procedure is to keep the resin at a temperature 50° C. higher than the glass transition temperature for 3 days, and then slowly cool it to room temperature.

The stretching treatment is performed to enhance the orientation of the resin by stretching the resin and to enhance the crystallinity. As a procedure for the drawing treatment, the resin may be melted at a temperature higher than the melting point by 30°C or more and stirred to draw the melted material by a factor of about 1 to 10 to form a fibrous form. exemplified. The maximum draw ratio in the drawing process is appropriately set according to the melt viscosity of the resin. When using an extruder, the number of nozzle openings is not particularly limited, but the greater the number, the better the productivity. The stretched resin is subjected to processing such as pulverization and cutting to become resin powder.

As a treatment using ultrasonic waves, glycerin (manufactured by Tokyo Kasei Kogyo Co., Ltd., reagent grade) solvent is added to the resin powder about 5 times the amount of the resin powder, and then heated to a temperature 20 ° C higher than the melting point of the resin. An example of the treatment is applying ultrasonic waves at 24 kHz and an amplitude of 60% for 2 hours using an ultrasonic generator such as an ultrasonicator UP200S manufactured by Shah. After the ultrasonic wave treatment, the resin powder is preferably washed with a solvent of isopropanol at room temperature and dried in a vacuum.

As the external electric field application treatment, a treatment of heating the powder to a temperature higher than the glass transition temperature, applying an alternating electric field (500 Hz) of 600 V/cm for 1 hour, and then slowly cooling the powder is exemplified.

<Shape>
The resin preferably consists of columnar particles. Here, "composed of columnar particles" means that when resin powder is observed using a scanning electron microscope JSM-7800FPRIME manufactured by JEOL Ltd., 20% or more of the observed resin particles are columnar particles. It means a particle (the same applies to substantially cylindrical particles and rectangular parallelepiped particles, which will be described later).

Moreover, the ratio of the height to the diameter or the long side of the bottom surface of the columnar particles (diameter or long side/height) is preferably 0.5 or more and 2 or less. The shape of the resin particles in the resin powder can be measured using the above scanning electron microscope. When the ratio is within this range, the heat transfer between particles becomes very good, and the bonding force between particles increases, leading to an improvement in strength.

The shape of the resin particles is preferably substantially cylindrical. A substantially circle means that the ratio of the major axis to the minor axis (major axis/minor axis) is 1-10.
The substantially cylindrical body is not particularly limited, but examples include a true cylindrical body, an elliptical cylindrical body, and the like, and a true cylindrical body is preferable. A part of the circular portion of the substantially cylindrical body may be missing.

Further, when the stretching treatment is performed, the shape of the resin particles is determined by the shape of the nozzle port of the extruder. For example, in order to obtain substantially cylindrical resin particles, the nozzle opening may be of a substantially circular shape, and in order to obtain rectangular parallelepiped resin particles, the nozzle opening may be of a rectangular or square shape.

The sizes of the circles on the opposing faces of the substantially cylindrical body may be different. However, since the bulk density can be increased if the shape is unified, the ratio of the diameters of the circles of the large surface and the small surface (large surface/small surface) is preferably 1.5 times or less. 0.1 times or less is more preferable.

The diameter of the substantially cylindrical body is not particularly limited and is appropriately selected depending on the purpose, but is preferably 5 μm or more and 200 μm or less. In addition, when the circular part of a substantially cylindrical body is an ellipse, a diameter means a length|longer_axis.
The height (distance between both surfaces) of the substantially cylindrical body is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 μm or more and 200 μm or less.

It is preferable that the substantially cylindrical resin particles do not have vertexes in order to increase the bulk density. The method for making the substantially cylindrical resin particles have no vertices is not limited as long as it is a method for rounding the vertexes of the resin particles. Examples include various known methods using a spheronizing device, such as surface melting by.

Moreover, it is preferable that the resin particles are rectangular parallelepipeds. In this case, each side of the bottom surface of the rectangular parallelepiped is preferably 5 μm or more and 200 μm or less, and the height is preferably 5 μm or more and 200 μm or less.

FIG. 4 shows an example of a SEM (scanning electron microscope) photograph of an example of resin particles. For example, as shown in FIG. 4, the column 21 has a first surface 22, a second surface 23 and side surfaces 24. As shown in FIG. The first surface 22 has a first opposing surface 22 a and a first surface outer peripheral region 22 b having a shape extending along the side surface 24 . The outer peripheral region 22b of the first surface is a surface that is continuous with the first opposing surface 22a via a curved surface and is substantially orthogonal to the first opposing surface 22a. The second surface 23 has a second opposing surface 23 a facing the first opposing surface 22 a and an outer peripheral region 23 b of the second surface extending along the side surface 24 . The outer peripheral region 23b of the second surface is a surface continuous with the second facing surface 23a via a curved surface, and is substantially perpendicular to the second facing surface 23a. Side 24 adjoins first surface 22 and second surface 23 . On the side surface 24, a first surface outer peripheral region 22b and a second surface outer peripheral region 23b extend.

In addition, the shape of the outer peripheral region 22b of the first surface and the outer peripheral region 23b of the second surface (hereinafter also referred to as “peripheral region”) may be a shape that can be distinguished from the side surface 24 on the SEM image. It includes a shape in which a part of the area is integrated with the side surface 24, a shape in which the outer peripheral area is in contact with the side surface 24, a shape in which a space exists between the outer peripheral area and the side surface 24, and the like. In addition, it is preferable that the outer peripheral region 22b of the first surface and the outer peripheral region 23b of the second surface are provided so as to have substantially the same surface direction as the surface direction of the side surface 24 .

In addition, as shown in FIG. 4 , the outer peripheral region 22 b of the first surface and the outer peripheral region 23 b of the second surface extend along the side surface 24 and are positioned on the side surface 24 . In addition, the characteristic structure of the first surface and the second surface that covers the vicinity of the connection area between the outer peripheral region 22b of the first surface and the outer peripheral region 23b of the second surface and the side surface 24 is the shape of a bottle cap. Also called

Here, the above "having no vertices" will be described in detail with specific examples.
In the substantially cylindrical resin powder, if it has a columnar shape with a bottom surface and a top surface (first surface 22 and second surface 23) but does not have a vertex, the bulk density can be increased. A vertex is a corner portion present in a cylinder.

The shape of the columnar particles will be described with reference to FIGS. 5 to 13. FIG. FIG. 5 is a schematic perspective view showing an example of a cylinder. 6 is a side view of the cylinder of FIG. 5; FIG. FIG. 7 is a side view showing an example of a shape having no vertices at the ends of a cylindrical body. FIGS. 8 to 13 are side views showing other examples of a cylindrical body having no vertex at its end.

When the cylindrical body shown in FIG. 5 is observed from the side, it has a rectangular shape as shown in FIG. 6, and has four corner portions, that is, vertices. An example of a shape that does not have vertices at the ends is shown in FIGS. 7 to 13. FIG. Confirmation of the presence or absence of the apex of the columnar particle can be determined from the projected image of the columnar particle on the side surface. For example, the side surfaces of the columnar particles are observed using a scanning electron microscope (apparatus name: S4200, manufactured by Hitachi Ltd.) or the like to obtain a two-dimensional image. In this case, the projected image becomes a quadrilateral, and if the part formed by two adjacent sides is the edge, and if it is formed by only two adjacent straight lines, an angle will be formed and it will have a vertex. , as in FIGS. 7 to 13, when the ends are formed by circular arcs, the ends do not have vertices.

<Characteristics>
<<50% cumulative volume particle size, volume average particle size, number average particle size, reflectance, transmittance>>
The 50% cumulative volume particle size of the resin powder is 5 μm or more and 100 μm or less, and more preferably 20 μm or more and 70 μm or less from the viewpoint of dimensional stability. If the 50% cumulative volume particle size is less than 5 μm, secondary particle aggregation will occur during the recoating operation to cleanly draw the powder during modeling, resulting in surface roughness. If the 50% cumulative volume particle size is more than 100 μm, the load on the underlying layer increases, resulting in surface roughness during recoating.

In addition, the ratio (Mv/Mn) obtained by dividing the volume average particle size (Mv) of the resin powder by the number average particle size (Mn) is 2.50 or less, and preferably 2.00 or less in terms of improving molding accuracy. 1.50 or less is more preferable, and 1.20 or less is still more preferable. If Mv/Mn is greater than 2.50, the problem of poor surface properties occurs.

The 50% cumulative volume particle size, volume average particle size (Mv), and number average particle size (Mn) of the resin powder are measured using a particle size distribution analyzer (Microtrac MT3300EXII, manufactured by Microtrac Bell). .

The reflectance for electromagnetic radiation is 10% or less, preferably 5% or less.
For measurement of reflectance, an infrared spectrometer 680-IR (manufactured by VARIAN) is used, and total transmission and total reflection are measured using a corresponding integrating sphere. The wavelength for measurement is changed continuously in the range of 2 μm to 20 μm, and the reflectance for each wavelength is obtained. To determine whether the reflectance for electromagnetic radiation is 10% or less, consider the electromagnetic radiation used during molding, and judge by the reflectance measured at the same wavelength as the wavelength of the electromagnetic radiation used during molding. . For example, when a CO ₂ laser is used as an electromagnetic beam for modeling, it is determined whether the reflectance is 10% or less when measured at a corresponding wavelength of 10.6 μm. For example, when infrared rays are used as electromagnetic rays other than the CO ₂ laser for modeling, it is determined whether the reflectance is 10% or less based on the reflectance measured at the corresponding wavelength.

Methods for adjusting the reflectance of the resin powder to a desired value include, for example, a method of adding an antireflection agent, a method of coating an antireflection agent around a reflecting inorganic component such as talc, and a method of coating an antireflection agent around particles. Examples include a method of coating with an inhibitor. If the reflectance is more than 10%, problems such as deterioration of surface properties occur.

Further, it is preferable that the transmittance of a 0.5 mm-thick layer formed of the powder for three-dimensional modeling is 10% or less when measured with an electromagnetic ray having a wavelength of 2 μm. Moreover, it is preferable that it is 0.1% or more.
A layer (sample) with a thickness of 0.5 mm is produced by using a powder for stereolithography, putting it into an injection molding machine, and using a mold with a thickness of 0.5 mm. In this embodiment, a 2 cm×2 cm layer with a thickness of 0.5 mm is produced. In addition, it is also possible to manufacture by 3DP of SLS system.

When the transmittance is 10% or less, it is possible to suppress the occurrence of excessive melting due to the heater heating at 13H in FIG. Tensile strength can be improved. The measurement of transmittance uses the same measuring apparatus as used for measurement of reflectance.

<<melting point>>
The melting point of the resin powder is determined by differential scanning calorimetry (DSC). In this case, according to ISO3146 (plastic transition temperature measurement method, JIS K7121), for example, using a differential scanning calorimeter such as Shimadzu DSC-60A, the temperature is increased at 10 ° C./min, and the resin powder is measured by DSC, and the temperature at the peak of the endothermic peak or the peak of the melting point obtained is defined as the melting point. When the resin powder has multiple melting points, the melting point in this embodiment refers to the higher melting point.

The melting point of the resin powder is preferably 100° C. or higher, more preferably 150° C. or higher, and even more preferably 200° C. or higher, in consideration of the heat resistance temperature when used for shaping the exterior of the product.

An example of a device capable of setting a reduced pressure at the above temperature during measurement is DP610 vacuum heating device manufactured by Yamato Scientific Co., Ltd.

<<Specific Gravity>>
The specific gravity of the resin powder is preferably 0.8 g/mL or more. When the specific gravity of the resin powder is 0.8 g/mL or more, secondary agglomeration of particles can be suppressed in the recoating process for forming a resin powder layer during modeling. On the other hand, in applications such as metal replacement, the specific gravity of the resin powder is preferably 3.0 g/mL or less from the needs of weight reduction.

Specific gravity is obtained by measuring true specific gravity. For the true specific gravity, for example, the volume of the sample is obtained by changing the volume and pressure of the gas (He gas) at a constant temperature using a dry automatic density meter (Accupic 1330, manufactured by Shimadzu Corporation) using the gas phase substitution method. , and by measuring the mass of this sample and calculating the density.

<<MFR>>
MFR (melt mass flow rate) is measured with a load of 2.16 kg using a melt mass flow rate measuring device (manufactured by Dynisco, model D405913) according to JIS7210 (ISO1133). The MFR of the resin powder is preferably 1 g/10 min or more and 50 g/10 min or less, more preferably 3 g/10 min or more and 35 g/10 min or less, from the viewpoint of resin fusion bonding characteristics during electromagnetic wave irradiation.

<Application>
The resin powder of this embodiment has an appropriate balance of parameters such as particle size, particle size distribution, heat transfer properties, melt viscosity, bulk density, fluidity, melting temperature, and recrystallization temperature, and can be , MJF (Multi Jet Fusion) method, or BJ (Binder Jetting) method.

The powders of the present embodiments have a proper balance of parameters such as particle size, particle size distribution, heat transfer properties, melt viscosity, bulk density, flowability, melt temperature, and recrystallization temperature, and can be used in SLS, SMS, It is suitably used in various three-dimensional modeling methods using resin powder, such as the MJF (Multi Jet Fusion) method or the BJ (Binder Jetting) method. The resin powder of the present embodiment is suitably used in surface contracting agents, spacers, lubricants, paints, grindstones, additives, secondary battery separators, foods, cosmetics, clothes, and the like. In addition, it may be used as a material used in fields such as automobiles, precision equipment, semiconductors, aerospace, and medicine, or as a metal substitute material.

A three-dimensional object formed by laser sintering using the resin powder of the present embodiment is smooth, suppresses the occurrence of orange peel, and has a surface with sufficient resolution.
Note that orange peel is a surface defect such as a rough surface, voids, or distortions on the surface of a three-dimensional object formed by laser sintering in the PBF method or the like. Among these surface defects, for example, voids not only deteriorate the aesthetic appearance but also affect the mechanical strength.

A three-dimensional object obtained from the resin powder of the present embodiment has good tensile strength, and the resin powder of the present embodiment has excellent long-term recyclability. By using the new resin powder and the recycled powder of the present embodiment and forming by the PBF method, the MJF method, etc., (a) the occurrence of orange peel, and (b) a significant decrease in mechanical performance due to recycling ( 30% or more reduction in tensile strength) is obtained.

A new resin powder is a resin powder that has never been used for modeling.
The recycled powder is, for example, resin powder that has not been used for modeling after 50 hours of modeling using a PBF type modeling apparatus (manufactured by Ricoh, AM S5500P).
According to the resin powder of the present embodiment, 30% by mass of new resin powder is added to the recycled powder, and even if molding for 50 hours is repeated two more times, the above (a) and (b) can be achieved. A solid model can be obtained that does not show any degradation.
The evaluations of (a) and (b) are performed using an ISO (International Organization for Standardization) 3167 Type 1A 150 mm length multi-purpose dog bone-like test specimen made of resin powder.

(3D object manufacturing device, 3D object manufacturing method, and 3D object)
The three-dimensional object manufacturing apparatus of the present invention comprises a supply tank storing the three-dimensional modeling powder of the present invention, layer forming means for forming a layer containing the three-dimensional modeling powder of the present invention, and and a curing means for curing by irradiating and, if necessary, other means.
The three-dimensional object manufacturing method of the present invention includes a layer forming step of forming a layer containing the three-dimensional object forming powder of the present invention, and a curing step of curing the layer by irradiating it with electromagnetic radiation. and other processes.

A three-dimensional modeling apparatus (a three-dimensional object manufacturing apparatus) that models using the above-described resin powder will be described with reference to FIG. 1 . FIG. 1 is a schematic diagram showing a stereolithography apparatus according to one embodiment of the present invention.

As shown in FIG. 1, the modeling apparatus 1 includes a supply tank 11 as an example of storage means for storing resin powder P for modeling, and an example of layer forming means for supplying the resin powder P stored in the supply tank 11. A roller 12 as a roller 12, a laser scanning space 13 in which the resin powder P supplied by the roller 12 is arranged and scanned by the laser L, an electromagnetic irradiation source 18 as an irradiation source of the laser L as an electromagnetic ray, and an electromagnetic irradiation source 18 has a reflecting mirror 19 for reflecting the laser L emitted by the laser scanning space 13 to a predetermined position. The modeling apparatus 1 also has heaters 11H and 13H for heating the resin powder P contained in the supply tank 11 and the laser scanning space 13, respectively.

Examples of electromagnetic radiation sources 18 include, but are not limited to, infrared radiation sources, microwave generators, radiant heaters, LED lamps, or combinations thereof.
Electromagnetic radiation includes, for example, _CO2 lasers, infrared rays, YAG lasers, infrared lasers (including high power planar laser VCSELs), and the like.

The reflecting surface of the reflecting mirror 19 moves based on the two-dimensional data of the 3D (three-dimensional) model while the electromagnetic irradiation source 18 is irradiating the laser L. The two-dimensional data of the 3D model indicates each cross-sectional shape obtained by slicing the 3D model at predetermined intervals. As a result, the reflection angle of the laser L is changed, so that the laser L is selectively irradiated to the portion indicated by the two-dimensional data in the laser scanning space 13 . The resin powder at the laser L irradiation position is melted and sintered to form a sintered layer (it can also be expressed that the resin powder particles within the selected region adhere to each other). That is, the electromagnetic irradiation source 18 functions as curing means for forming each sintered layer of the modeled object from the resin powder P. As shown in FIG.

Pistons 11P and 13P are provided in the supply tank 11 and the laser scanning space 13 of the modeling apparatus 1, respectively. The pistons 11P and 13P move the supply tank 11 and the laser scanning space 13 upward or downward with respect to the stacking direction of the modeled object when the modeling of the layers is completed. As a result, it becomes possible to supply new resin powder P to be used for modeling a new layer from the supply tank 11 to the laser scanning space 13 .

The modeling apparatus 1 selectively melts the resin powder P by changing the irradiation position of the laser using the reflecting mirror 19, but the present invention is not limited to such an embodiment. The resin powder of the present invention is also suitably used in a selective mask sintering (SMS) type modeling apparatus. In the SMS method, for example, part of the resin powder is masked with a shielding mask, electromagnetic rays are irradiated, and electromagnetic rays such as infrared rays are irradiated to the unmasked portion, and the resin powder is selectively melted. do. When the SMS process is used, the resin powder P preferably contains at least one heat absorbing agent that enhances infrared absorption properties, or a dark substance.

Exemplary heat absorbers or dark substances include carbon fibers, carbon black, carbon nanotubes and cellulose nanofibers. As for the SMS process, for example, the one described in US Pat. No. 6,531,086 can be preferably used.

FIG.2 and FIG.3 is a conceptual diagram for demonstrating the manufacturing method of a three-dimensional molded article. A method for manufacturing a three-dimensional object using the modeling apparatus 1 will be described with reference to FIGS. 2 and 3. FIG.

The resin powder P stored in the supply tank 11 is heated by the heater 11H. The temperature of the supply tank 5 is preferably as high as possible below the melting point of the resin particles P from the viewpoint of suppressing warping when the resin particles P are melted by laser irradiation. It is preferable that the melting point of the resin powder P is lower than the melting point of the resin powder P by 10° C. or more from the point of view of prevention.

As shown in (A) of FIG. 2, the engine of the modeling apparatus 1 drives the roller 12 to supply the resin powder P in the supply tank 5 to the laser scanning space 13 to level the ground as an example of the layer forming process. Thus, a resin powder layer (powder layer) having a thickness T corresponding to one layer is formed. The resin powder P supplied to the laser scanning space 13 is heated by the heater 13H.

The temperature of the laser scanning space 13 is preferably as high as possible in terms of suppressing warping when the resin particles P are melted by laser irradiation. It is preferably lower than the melting point of the resin powder P by 5°C or more.

The engine of the modeling apparatus 1 receives inputs of a plurality of two-dimensional data generated from the 3D model. As shown in FIG. 2B, the engine of the modeling apparatus 1 moves the reflecting surface of the reflecting mirror 19 based on the two-dimensional data closest to the bottom surface among the plurality of two-dimensional data, while moving the electromagnetic irradiation source. 18 is irradiated with a laser. The output of the laser is not particularly limited and is appropriately selected according to the purpose, but is preferably 10 watts or more and 150 watts or less.

The laser irradiation melts the resin powder P at positions corresponding to the pixels indicated by the two-dimensional data on the bottom side of the powder layer. When the laser irradiation is completed, the melted resin is cured to form a sintered layer having a shape indicated by the two-dimensional data on the bottom side (an example of the curing process).

The thickness T of the sintered layer is not particularly limited, but the average value is preferably 10 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more. The thickness T of the sintered layer is not particularly limited, but the average value is preferably less than 200 μm, more preferably less than 150 μm, and even more preferably less than 120 μm.

As shown in FIG. 3A, when the bottommost sintered layer is formed, the engine of the modeling apparatus 1 forms a modeling space with a thickness T corresponding to one layer in the laser scanning space 13. , the piston 13P lowers the laser scanning space 13 by the thickness T of one layer. Further, the engine of the modeling apparatus 1 raises the piston 11P so that new resin powder P can be supplied. Subsequently, as shown in FIG. 3A, the engine of the modeling apparatus 1 drives the rollers 12 to supply the resin powder P in the supply tank 5 to the laser scanning space 13 to level the ground. A powder layer having a layer thickness T is formed (an example of a layer forming process).

As shown in FIG. 3B, the engine of the modeling apparatus 1 moves the reflecting surface of the reflecting mirror 19 based on the second-layer two-dimensional data from the bottom side of the plurality of two-dimensional data. , causes the electromagnetic radiation source 18 to irradiate the laser. As a result, the resin powder P at the positions corresponding to the pixels indicated by the two-dimensional data of the second layer from the bottom side of the powder layer is melted. When the laser irradiation is completed, the melted resin is cured, and a sintered layer having a shape indicated by the two-dimensional data of the second layer from the bottom side is formed in a state of being laminated on the sintered layer closest to the bottom side. be. In addition, you may cool, after melting a resin powder as needed.

The modeling apparatus 1 stacks the sintered layers by repeating the layer forming process and the curing process. When modeling based on all of the plurality of two-dimensional data is completed, a three-dimensional model having the same shape as the 3D model is obtained.

The three-dimensional object that is formed from the above resin powder is not particularly limited, but is a prototype of an electronic device part, or an automobile part, or a prototype for a strength test, or an aerospace, or a dress-up tool for the automobile industry, etc. Examples include small-lot products used for

The PBF method is expected to be superior in strength compared to other methods such as FDM (fused deposition modeling) and ink jet method, so it can be used as a practical product. Although the production speed is not as high as mass production such as injection molding, the required production volume can be obtained, for example, by mass-producing small parts in a flat shape.

In addition, the method of manufacturing a three-dimensional object in the PBF method used in this embodiment does not require a mold like injection molding, so in the production of prototypes and prototypes, overwhelming cost reduction and delivery time reduction are achieved. can do.

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Example 1)
99.0 parts by mass of polybutylene terephthalate (PBT) resin (trade name: Novaduran 5020, manufactured by Mitsubishi Engineering-Plastics, melting point: 218 ° C.), hindered phenolic antioxidant (trade name: AO-330, 1,3 ,5-tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)-2,4,6-trimethylbenzene, manufactured by ADEKA), 0.2 parts by mass, and a phosphite-based antioxidant (trade name: PEP-36, 3,9-Bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, manufactured by ADEKA) Add 0.4 parts by mass, add 0.4 parts by mass of NUBIAN BLACK NH-805 (manufactured by Oriental Chemical Industry Co., Ltd.) as black dye 1, and stretch 3 times using a single screw extruder (D2020 manufactured by Toyo Seiki Co., Ltd.) A fiber having a diameter of 60 μm was formed by winding as described above.

Thereafter, using a cutting device NZI0606 (manufactured by Ogino Seiki Co., Ltd.), the resin fibers were cut into widths of 60 μm or more and 70 μm or less to obtain resin powder.
The 50% cumulative volume particle size of the obtained resin powder was 65 μm. When the shape was confirmed using a scanning electron microscope JSM-7800FPRIME manufactured by JEOL Ltd., the wire diameter was 60 μm and the diameter was 60 μm. The obtained resin powder was processed at 1000 rpm for 20 minutes using a Q mixer (manufactured by Mitsui Coke Co., Ltd.) for surface melting by mechanical friction to obtain substantially cylindrical particles. This was used as the powder for stereolithography of Example 1. The formulation is shown in Table 1.

(Example 2)
Three-dimensional modeling of Example 2 in the same manner as in Example 1 except that 0.2 parts by mass of AF Black E-2B (manufactured by Dainichiseika Co., Ltd.) was added as black pigment 1 in addition to the formulation of Example 1. powder was obtained.

(Example 3)
In Example 1, the polybutylene terephthalate (PBT) resin was changed to polyamide 66 (PA66) resin (trade name: Leona 1300S, manufactured by Asahi Kasei Chemicals, melting point: 265 ° C.), and the two antioxidants of Example 1 were used. A three-dimensional modeling powder of Example 3 was obtained in the same manner as in Example 1, except that 0.1 part by mass of copper acetate was added as a polymerization inhibitor.

(Example 4)
In Example 1, polybutylene terephthalate (PBT) resin was mixed with polypropylene talc (PP/talc) resin (trade name: Novatec JP5GA, manufactured by Japan Polypropylene Corporation, melting point: 130°C, glass transition temperature: 0°C. ) in the same manner as in Example 1 to obtain a powder for three-dimensional modeling of Example 4.

(Example 5)
In Example 1, polybutylene terephthalate (PBT) resin was changed to polyether ether ketone (PEEK) resin (trade name: HT P22PF, manufactured by VICTREX, melting point: 343°C, glass transition temperature: 143°C). A three-dimensional modeling powder of Example 5 was obtained in the same manner as in Example 1.

(Example 6)
Example 6 was prepared in the same manner as in Example 1, except that the polybutylene terephthalate (PBT) resin in Example 1 was changed to polyacetal (POM) resin (trade name: Tenac 4060, manufactured by Asahi Kasei Corporation, melting point: 175°C). was obtained.

(Comparative example 1)
A three-dimensional modeling powder of Comparative Example 1 was obtained in the same manner as in Example 1, except that the black dye 1 was not used.

(Comparative example 2)
A three-dimensional modeling powder of Comparative Example 2 was obtained in the same manner as in Example 3, except that black dye 1 and black pigment 1 were not used.

(Comparative Example 3)
Three-dimensional modeling powder of Comparative Example 3 was obtained in the same manner as in Example 4, except that black dye 1 was not used.

(Comparative Example 4)
Three-dimensional modeling powder of Comparative Example 4 was obtained in the same manner as in Example 5, except that black dye 1 was not used.

(Comparative Example 5)
Three-dimensional modeling powder of Comparative Example 5 was obtained in the same manner as in Example 6, except that black dye 1 was not used.

(measurement)
"50% Cumulative Volume Particle Size", "Volume Average Particle Size (Mv)", and "Number Average Particle Size (Mn)" of the three-dimensional modeling powders obtained in Examples and Comparative Examples were determined as follows. , "Reflectance", "Melting Point", "Specific Gravity", and "MFR" were measured. Table 2 shows the results.

<50% Cumulative Volume Particle Size, Volume Average Particle Size (Mv), and Number Average Particle Size (Mn)>
The 50% cumulative volume particle size, volume average particle size (Mv), and number average particle size (Mn) are measured using a particle size distribution measuring device (microtrac MT3300EXII manufactured by Microtrac Bell), and the particle refraction of each resin powder. Measured by the dry (atmospheric) method without using solvents. The particle refractive index is polybutylene terephthalate (PBT) resin: 1.57, polyamide 66 (PA66) resin: 1.53, polyamide 9T (PA9T) resin: 1.53, polypropylene (PP) resin: 1.48, poly Ether ether ketone (PEEK) resin: 1.57, polyacetal (POM) resin: 1.48. A volume average particle size/number average particle size (Mv/Mn) was calculated from the obtained volume average particle size and number average particle size.

<Reflectance and transmittance>
For the three-dimensional modeling powder of each example and comparative example, the infrared spectrometer 680-IR (manufactured by VARIAN) was used to measure the reflectance, and the corresponding integrating sphere was used to measure total transmission and total reflection. did The wavelength for measurement was changed continuously in the range of 2 μm to 20 μm, and the reflectance for each wavelength was obtained. Assuming a CO ₂ laser as the electromagnetic radiation used during modeling, the value at a wavelength of 10.6 μm was taken as the reflectance. For the transmittance measurement, a layer having a thickness of 0.5 mm formed using each three-dimensional modeling powder is used as a measurement object (sample). A layer (sample) with a thickness of 0.5 mm was produced by using each three-dimensional modeling powder, putting it into an injection molding machine, and using a mold with a thickness of 0.5 mm. In this test, a 0.5 mm thick layer of 2 cm x 2 cm was produced.

<Melting point>
The melting point of the resin powder of each example and comparative example was measured according to ISO3146. Using a differential scanning calorimeter (DSC-60A manufactured by Shimadzu Corporation), the temperature is raised at 10 ° C./min to perform DSC measurement of the resin powder, and the temperature at the peak of the endothermic peak or the peak of the melting point obtained. was taken as the melting point. When the resin powder has multiple melting points, the higher melting point is used.

<Specific gravity>
The specific gravity is determined by changing the volume and pressure of the gas (He gas) at a constant temperature using a dry automatic density meter (Accupic 1330, manufactured by Shimadzu Corporation) using a gas phase substitution method, and determining the volume of the sample. was measured by measuring the mass of the sample and measuring the density of the sample.

<Melt mass flow rate (MFR)>
According to JIS7210 (ISO1133), the melt mass flow rate (MFR) was measured with a load of 2.16 kg using a melt mass flow rate measuring device (manufactured by Dynisco, model D405913). The measurement temperature was set at +15°C of the melting point shown in Table 2. After filling the resin powder, the container was heated for 2 minutes or longer to sufficiently melt the resin powder, and then the measurement was performed.

(evaluation)
The three-dimensional modeling powder obtained in each example and comparative example was evaluated as follows. Table 3 shows the results.

<Minimum molding radius>
Using a CO ₂ laser (wavelength: 10.6 μm) as an electromagnetic beam, a 5 cm×5 cm square shape with a height of 1 mm was produced from the resin powder of each example and comparative example. At this time, models having cylindrical holes of 1 mm, 2 mm, and 4 mm were produced. By confirming this modeled object, the minimum shapeable radius was evaluated. The smaller the shapeable minimum radius (mm), the better the evaluation result.

<Presence or absence of excessive melting>
For the resin powder of each example and comparative example, the molding temperature is increased by 1° C., and the maximum temperature of the molding surface of the resin that can be molded is visually confirmed. After that, by irradiating electromagnetic rays (CO ₂ laser, wavelength 10.6 μm), adhesion between resins is confirmed, and then tensile test specimens are formed. At that time, the presence or absence of excessive melting was evaluated. The case where the sample was completed to the end was defined as no occurrence.

<Orange peel property>
For the resin powders of each example and comparative example, a three-dimensional model was manufactured using an SLS model model (manufactured by Ricoh Co., Ltd., AM S5500P). The setting conditions were 0.1 mm layer average thickness, CO ₂ laser power of 10 watts to 150 watts, laser scanning space of 0.1 mm, temperature -3° C. from the melting point was used for the part bed temperature. ISO (International Organization for Standardization) 3167 Type 1A 150 mm length multipurpose dog bone-like test specimen ( Specimens were made with a central portion of 80 mm length, 4 mm thickness and 10 mm width). The surface of the obtained three-dimensionally shaped article was observed, and the presence or absence of orange peel property was evaluated based on the following evaluation criteria.

[Evaluation criteria]
None: Surface defects such as rough surfaces, voids, and distortions are not generated Yes: Surface defects such as rough surfaces, voids, and distortions are generated

<Tensile strength>
The tensile strength of the resin powder in the SLS process was measured as follows. Using an SLS modeler (AM S5500P, manufactured by Ricoh), 10 kg of powder was added into the feed bed of the SLS modeler. The setting conditions for the SLS molding apparatus were the same as those for the evaluation of the orange peel property.
Using the resin powders of Examples and Comparative Examples, a tensile test specimen was elongated in the Y-axis direction (parallel to the rotation axis of the roller 12 in FIG. 1) at the center of the laser scanning space 13 with an SLS molding apparatus. Five tensile test specimens were molded side-by-side.
The distance between each model layer is 5 mm. Tensile test specimens are ISO (International Organization for Standardization) 3167 Type 1A 150 mm long multi-purpose dog-bone-like test specimens (specimens have a central portion that is 80 mm long, 4 mm thick and 10 mm wide). In this process, first, 20 modeling layers were laminated to form a tensile test sample, and then an arbitrary sample was formed, and the modeling time was set to take 50 hours.
Tensile strength of the three-dimensional model obtained at this time was measured using a tensile tester (AGS-5kN, manufactured by Shimadzu Corporation) according to ISO 527. Note that the test speed in the tensile test was constant at 50 mm/min. A reduction rate of 20% or less relative to strength in injection molding with the resin was considered acceptable. The strength of the injection molded product is PBT: 55 MPa, PA66: 65 MPa, PP talc: 30 MPa, PEEK: 97 MPa, and POM: 67 MPa.

1 modeling device 11 supply tank 11H heater 11P piston 12 roller 13 laser scanning space 13H heater 13P piston 18 electromagnetic irradiation source 19 reflecting mirror 21 column 22 first surface 22a first opposing surface 22b outer peripheral region 23 of the first surface Second surface 23a Second opposing surface 23b Peripheral region 24 of second surface Side surface

Japanese Patent Application Laid-Open No. 2001-247754

Claims (11)

A three-dimensional modeling powder that contains a resin and a black dye and forms a three-dimensional article when irradiated with electromagnetic radiation,
The 50% cumulative volume particle size is 5 μm or more and 100 μm or less, the volume average particle size/number average particle size is 2.50 or less, and the reflectance for electromagnetic rays is 10% or less, and the reflectance is as follows. A powder for three-dimensional modeling characterized by being obtained by measurement .
[measurement]
Using an infrared spectrometer 680-IR (manufactured by VARIAN), the value at a wavelength of 10.6 μm is taken as the reflectance. 2. The powder for stereolithography according to claim 1, wherein the reflectance for the electromagnetic radiation is 5% or less. 3. The layer according to claim 1 or 2, wherein the layer composed of the powder for three-dimensional modeling and having a thickness of 0.5 mm formed by an injection molding machine has a transmittance of 10% or less as measured by electromagnetic radiation having a wavelength of 2 μm. 3D modeling powder. 4. The powder for stereolithography according to claim 1, wherein the 50% cumulative volume particle size is 20 μm or more and 70 μm or less. The resin is composed of columnar particles,
5. Any one of claims 1 to 4, wherein the ratio of the height to the diameter or long side of the base of the columnar particles (diameter or long side/height) is 0.5 or more and 2 or less. Solid modeling powder as described. The resin is composed of substantially cylindrical particles, the diameter of the bottom surface of the substantially cylindrical body is 5 μm or more and 200 μm or less, and the height is 5 μm or more and 200 μm or less, or the resin is composed of rectangular parallelepiped particles, 6. The powder for stereolithography according to any one of claims 1 to 5, wherein each side of the bottom surface of the rectangular parallelepiped is 5 µm or more and 200 µm or less, and the height is 5 µm or more and 200 µm or less. An antireflection agent is included, and the black dye is included as the antireflection agent,
7. The powder for stereolithography according to any one of claims 1 to 6, wherein the antireflection agent is contained in an amount of 0.01% by mass or more and 0.5% by mass or less with respect to the resin. 8. The three-dimensional modeling powder according to claim 7, wherein the antireflection agent further contains a black pigment. A supply tank in which the three-dimensional modeling powder according to any one of claims 1 to 8 is stored;
a layer forming means for forming a layer containing the three-dimensional modeling powder according to any one of claims 1 to 8;
and a curing means for curing the layer by irradiating it with an electromagnetic ray. A layer forming step of forming a layer containing the three-dimensional modeling powder according to any one of claims 1 to 8;
and a curing step of curing the layer by irradiating it with an electromagnetic ray. A powder that contains a resin and a black dye and that hardens when irradiated with electromagnetic radiation,
The 50% cumulative volume particle size is 5 μm or more and 100 μm or less, the volume average particle size/number average particle size is 2.50 or less, and the reflectance for electromagnetic rays is 10% or less, and the reflectance is as follows. A powder characterized by being obtained by measurement .
[measurement]
Using an infrared spectrometer 680-IR (manufactured by VARIAN), the value at a wavelength of 10.6 μm is taken as the reflectance.

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