WO2021090768A1 - Polymer powder for producing 3-dimensional model, method for producing 3-dimensional modeled object through powder bed melt bonding method using polymer powder, and 3-dimensional modeled object - Google Patents

Abstract

This polymer powder for producing a three-dimensional modeled object through a powder bed melt bonding method is formed of polyamide. Said polymer powder for producing a three-dimensional modeled object is characterized by containing, with respect to the polymer powder, less than 0.001 mass% of at least one polymer (A) which has a number average particle diameter of 1-100 μm, a sphericity of at least 80, and a weight average molecular weight of at most 20,000 and which is selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, a polyethylene glycol-polypropylene glycol copolymer, and alkyl ethers thereof.

Description

Polymer powder for producing 3D model, method for producing 3D model by powder bed fusion bonding method using polymer powder, and 3D model

The present invention relates to a three-dimensional model obtained by a powder bed melt-bonding method, a polymer powder preferably used to obtain the three-dimensional model, and a method for producing a three-dimensional model using the polymer powder.

The powder bed fusion bonding method is known as a technique for manufacturing a three-dimensional modeled object (hereinafter, may be referred to as a modeled object). In particular, the powder sintering method involves a thin layer forming step of developing a powder into a thin layer, and irradiating the formed thin layer with a laser beam in a shape corresponding to the cross-sectional shape of the object to be modeled to combine the powder. It is a method of manufacturing by sequentially repeating the cross-sectional shape forming step of forming, and has an advantage that a support member is unnecessary, which is suitable for precision modeling as compared with other modeling methods.

Ideally, the polymer powder suitable for the above method has a spherical shape in order to improve fluidity.

In response to such a problem, Non-Patent Document 1 discloses a polymer powder composed of polyamide 12 having a relatively high spherical morphology. Patent Document 1 discloses a spherical polyamide powder obtained by making particles using polyethylene glycol that is incompatible with a polyamide resin. Patent Document 2 discloses a polymer powder containing 0.001% by mass to 5% by mass of a polyol.

Japanese Patent No. 4846425 Japanese Patent No. 5129973

However, although the technique of Non-Patent Document 1 discloses a polyamide powder having a spherical shape, its sphericity is insufficient and there is room for improvement in fluidity.

In the technique of Patent Document 1, since the molecular weight of polyethylene glycol used for particle formation is high and the entire system has a high viscosity, the obtained powder is a powder in which a large amount of polyethylene glycol remains inside the powder, and such powder is used. There was a problem that the fluidity deteriorated when it was made into a modeled object.

Although the technique of Patent Document 2 is excellent in fluidity, there is a problem that the residual amount of the polyol in Patent Document 2 causes thermal deterioration, and the surface smoothness deteriorates when a modeled product is formed using such powder.

Therefore, an object of the present invention is to obtain a polyamide powder having high fluidity and excellent surface smoothness when the polyamide powder is used to form a model.

In order to solve the above problems, it has the following configuration.

That is, the polymer powder used in the powder bed melt bonding method of the present invention (hereinafter, may be referred to as polyamide powder) is a polymer powder for producing a three-dimensional model by the powder bed melt bonding method. The polymer powder is composed of polyamide, has a D50 particle size of 1 to 100 μm, a sphericity of 80 or more, and a weight average molecular weight of 20,000 or less. Polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol-polypropylene. Produce a three-dimensional model characterized by containing less than 0.001% by mass of one or more polymers (A) selected from the group consisting of glycol copolymers and alkyl ethers thereof with respect to the polymer powder. It is a polymer powder for

Further, the method for producing the three-dimensional model of the present invention is a method for producing the three-dimensional model by the powder bed fusion bonding method using the polymer powder.

Further, the three-dimensional model of the present invention is a three-dimensional model obtained by a powder bed fusion bonding method using a polymer powder.

The polymer powder of the present invention can obtain a polyamide powder having high fluidity and excellent surface smoothness when the polyamide powder is used as a model.

It is a scanning electron micrograph of the polyamide powder obtained in Example 2. FIG. It is a scanning electron micrograph of the polyamide powder obtained in Example 5.

Hereinafter, the present invention will be described in detail.

The polymer powder in the present invention is composed of a polyamide having a structure containing an amide group. Specific examples of such polyamides include polycaproamide (polyamide 6), polyundecamide (polyamide 11), polylauroamide (polyamide 12), polyhexamethylene adipamide (polyamide 66), and polydecamethylenese. Bacamide (polyamide 1010), polydodecamethylene sebacamide (polyamide 1012), polydodecamethylene dodecamide (polyamide 1212), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), poly Decamethylene adipamide (polyamide 106), polydodecamethylene adipamide (polyamide 126), polyhexamethylene terephthalamide (polyamide 6T), polydecamethylene terephthalamide (polyamide 10T), polydodecamethylene terephthalamide (polyamide 12T) , Polycaproamide / polyhexamethylene adipamide copolymer (polyamide 6/66), polycaproamide / polylauroamide copolymer (6/12) and the like. Among them, polycaproamide (polyamide 6), polyundecamide (polyamide 11), polylauroamide (polyamide 12), polyhexamethylene adipamide (polyamide 66), and polyhexamethylene adipamide (polyamide 66) are preferable because they can be easily controlled into a true spherical shape. Polydecamethylene sebacamide (polyamide 1010), polydodecamethylene sebacamide (polyamide 1012), polydodecamethylene dodecamide (polyamide 1212), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 610) 612) and the like. Further, from the viewpoint of thermal properties suitable for modeling, polycaproamide (polyamide 6), polyundecamide (polyamide 11), polylauroamide (polyamide 12), polyhexamethylene adipamide (polyamide 66), poly Decamethylene sebacamide (polyamide 1010) and polydodecamethylene sebacamide (polyamide 1012) are particularly preferable.

Among these, polycaproamide (polyamide 6) and polyhexamethylene adipamide (polyamide 66) are remarkably preferable in terms of heat resistance during molding. In terms of compatibility with general-purpose molding machines, polyundecamide (polyamide 11), polylauroamide (polyamide 12), polydecamethylene sebacamide (polyamide 1010), and polydodecamethylene sebacamide (polyamide 1012) ) Is remarkably preferable.

The polyamide may be copolymerized as long as the effect of the present invention is not impaired. As the copolymerizable component, an elastomer component such as polyolefin or polyalkylene glycol that imparts flexibility, a rigid aromatic component that improves heat resistance and strength, and the like can be appropriately selected. Further, as will be described later, a copolymer component for adjusting the terminal group may be used in order to reuse the polymer powder by the powder bed melt bonding method. Examples of such copolymerization components include monocarboxylic acids such as acetic acid, hexanoic acid, lauric acid and benzoic acid, and monoamines such as hexylamine, octylamine and aniline.

The range of the weight average molecular weight of the polyamide is preferably 10,000 to 1,000,000. The higher the weight average molecular weight, the slower the crystallization rate, and the warpage caused by crystallization during molding can be suppressed. Therefore, the lower limit is preferably 20,000 or more, more preferably 40,000 or more, and further 70,000 or more. Preferably, 100,000 or more is particularly preferable, and 200,000 or more is most preferable. If the molecular weight is too high, the viscosity becomes high and the adhesion between the layers at the time of molding deteriorates. Therefore, the upper limit is preferably 800,000 or less, more preferably 500,000 or less, and particularly preferably 300,000 or less.

The weight average molecular weight of the polyamide constituting the polymer powder refers to a value obtained by measuring the weight average molecular weight by gel permeation chromatography using hexafluoroisopropanol as a solvent and converting it with polymethylmethacrylate.

The D50 particle size of the polymer powder of the present invention is in the range of 1 to 100 μm. When the D50 particle size exceeds 100 μm, the particle size becomes larger than the modeling surface and the surface becomes rough. If the D50 particle size is less than 1 μm, it is so fine that it easily adheres to a coater or the like during modeling, and the modeling chamber cannot be raised to the required temperature. The upper limit of the D50 particle size of the polymer powder is preferably 90 μm or less, more preferably 80 μm or less, still more preferably 70 μm or less. The lower limit is preferably 5 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more.

The D50 particle size of the polymer powder is a particle size (D50 particle size) at which the cumulative frequency from the small particle size side of the particle size distribution measured by the laser diffraction type particle size distribution meter is 50%.

The particle size distribution of the polymer powder is represented by D90 / D10, which is the ratio of the particle size distributions D90 to D10, and is preferably less than 3.0. It is preferable that the particle size distribution is narrow because the difference in meltability during molding due to the difference in particle size is eliminated, the undissolved residue inside is avoided, and the appearance is good. Therefore, D90 / D10 is preferably less than 2.5, more preferably less than 2.0, and even more preferably less than 1.5. The lower limit is theoretically 1.0.

D90 / D10 showing the particle size distribution of the polymer powder in the present invention has a particle size (D90) at which the cumulative frequency from the small particle size side of the particle size distribution measured by the laser diffraction type particle size distribution meter is 90%. It is a value divided by the particle size (D10) at which the cumulative frequency from the small particle size side is 10%.

The sphericity indicating the sphericity of the polymer powder of the present invention is 80 or more and 100 or less. If the sphericity is less than 80, the fluidity deteriorates and the surface of the modeled object becomes rough. The sphericity is preferably 85 or more and 100 or less, more preferably 90 or more and 100 or less, still more preferably 93 or more and 100 or less, particularly preferably 95 or more and 100 or less, and remarkably preferably 97 or more and 100 or less.

The sphericity of the polymer powder of the present invention is determined by observing 30 particles at random from a scanning electron microscope photograph and following the following formulas from the minor axis and the major axis.

Note that S: sphericity, a: major axis, b: minor axis, n: number of measurements 30.

The smoothness of the surface and the solidity of the inside of the polymer powder of the present invention can be expressed by the BET specific surface area due to gas adsorption. When the surface of the polymer powder is smooth and the inside is solid, the surface area thereof is small, the fluidity is improved, and the surface of the modeled object is smooth, which is preferable. Here, the smoother the surface, the smaller the BET specific surface area. Specifically, ^{it is preferably 10 m 2} / g or less, more preferably 5 m ² / g or less, further preferably 3 m ² / g or less, and particularly preferably 1 m ² / g or less, which is the most. It is preferably 0.5 m ² / g or less. The lower limit is theoretically 0.05 m ² / g when the particle size is 100 μm.

The BET specific surface area is measured according to the Japanese Industrial Standards (JIS standard) JIS R 1626 (1996) "Measuring method of specific surface area by gas adsorption BET method".

The solidity of the polymer powder of the present invention can also be evaluated by the following formula showing the ratio of the BET specific surface area to the theoretical surface area calculated from the D50 particle size. The closer the above ratio is to 1, the more adsorption occurs only on the outermost surface of the particles, indicating that the particles have a smooth surface and are solid. 5 or less is preferable, 4 or less is more preferable, 3 or less is further preferable, and 2 or less is most preferable. The lower limit is theoretically 1.

The ratio of R: surface area, D: D50 particle size, α: polyamide density, and A: BET specific surface area are shown.

In the production of the polymer powder of the present invention, the polyamide monomer (B) described in WO2018 / 207728, which was previously disclosed by the present inventors, is simply added to the polymer (A) in the presence of the polymer (A). A method can be used in which the polymer (B) is polymerized and polymerized at a temperature higher than the crystallization temperature of the polyamide obtained, and then the powder is washed and dried. At this time, one or more polymers (A) selected from the group consisting of polyethylene glycol having a weight average molecular weight of 20,000 or less, polypropylene glycol, polytetramethylene glycol, polyethylene glycol-polypropylene glycol copolymer, and alkyl ethers thereof. ), It is possible to make the content less than 0.001% by mass with respect to the polymer powder by washing, the fluidity of the polymer powder is improved, and the surface of the obtained model is Found to be smooth.

When the weight average molecular weight of the polymer (A) exceeds 20,000, the solubility of the polymer (A) deteriorates, which makes cleaning difficult, and further, the particles are bonded via the polymer (A) remaining in the particles. Liquidity deteriorates. The weight average molecular weight is 20,000 or less, preferably 14,000 or less, more preferably 10,000 or less, particularly preferably 6,000 or less, still more preferably 4,000 or less, and most preferably 2,000 or less. is there. The lower limit is 500.

Further, as the polymer (A), it is preferable that the content of polar groups such as hydroxyl groups, amino groups and carboxyl groups is small because the fluidity is improved. In particular, the polymer (A) which is a hydroxyl group and is contained only at both ends of the molecule is preferable. Specific examples are one or more compounds selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol-polypropylene glycol copolymer, and alkyl ethers thereof. Since water can be used for washing and the like, and all processes from powder production to washing can be treated with water only, polyethylene glycol, polyethylene glycol-polypropylene glycol copolymer, and alkyl ethers thereof are preferable, polyethylene glycol, and alkyls thereof. The ether form is most preferable. Two or more of these may be used at the same time as long as the present invention is not impaired.

The weight average molecular weight of the polymer (A) indicates the weight average molecular weight obtained by converting the value measured by gel permeation chromatography with polyethylene glycol using water as a solvent. When the polymer (A) is insoluble in water, tetrahydrofuran is used as a solvent, and the weight average molecular weight obtained by converting the value measured by gel permeation chromatography into polystyrene is shown.

By using the polymer (A) of the present invention, it is possible to reduce the polymer (A) to less than 0.001% by mass with respect to the polymer powder by the washing step. Within such a range, the high molecular weight of the polymer (A) and the aggregation of particles derived from polar groups are suppressed, and a spherical polymer powder suitable for a three-dimensional model exhibiting high fluidity can be produced. Further, when the content of the polymer (A) is less than 0.001% by mass, excellent surface smoothness can be obtained in the case of a modeled product. Further, coloring, gelation, deterioration of mechanical properties and the like caused by the polymer (A) can be avoided.

The smaller the content of the polymer (A), the better the fluidity. Therefore, it is preferably 0.0008% by mass or less, more preferably 0.0005% by mass or less, and particularly preferably 0.0003% by mass or less. The lower limit is indispensable to be more than 0 because the polymer powder becomes spherical solid and surface smoothed by using the polymer (A) and the fluidity is improved. When the content of the polymer (A) is 0, the particles agglomerate and the fluidity is inferior.

The content of the polymer (A) is a value quantified by gel permeation chromatography using water as a solvent after extracting the polymer powder with water or an organic solvent and then removing the solvent. The lower limit of detection by this measuring method is 0.0001%.

It is preferable that the polymer powder of the present invention does not contain an organic solvent. When an organic solvent is contained, it is not preferable because the organic solvent is volatilized by heating during molding by the powder bed melt-bonding method and contaminates the inside of the molding machine. In the present invention, the organic solvent refers to an organic compound that is liquid at normal temperature and pressure. However, one or more polymers selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol-polypropylene glycol copolymer having a weight average molecular weight of 20,000 or less, and alkyl ethers thereof are such. Not included in organic solvents. As a method for confirming that the organic solvent is not contained, a known method for analyzing the concentration of volatile organic compounds can be used, and examples thereof include a gas chromatograph mass spectrometer equipped with a heat desorption device. Not contained in the present invention means that the peak indicating the organic solvent by the gas chromatograph mass spectrometer is below the detection limit, and the lower limit of detection in the present invention is 0.0001%.

The effect of the polymer powder of the present invention is that the polymer powder exhibits high fluidity. The index can be adopted by any known measuring method. A specific example is the angle of repose, which is 40 degrees or less. It is preferably 37 degrees or less, more preferably 33 degrees or less, and particularly preferably 30 degrees or less. The lower limit is usually 20 degrees or more.

The polymer powder of the present invention may be added with other formulations as long as the present invention is not impaired. Examples of the compounding agent include an antioxidant and a heat-resistant stabilizer in order to suppress thermal deterioration due to heating during molding by the powder bed melt-bonding method. Examples of antioxidants and heat-stabilizing agents include hindered phenols, hydroquinones, phosphites and their substitutes, phosphite, hypophosphite and the like. Others include pigments and dyes for coloring, plasticizers for adjusting viscosity, flow aids for modifying fluidity, antistatic agents for functionalizing, flame retardants and carbon black, silica, titanium dioxide, glass fiber and glass. Examples include fillers such as beads and carbon fibers. Known substances can be used as these, and they may be present inside or outside the polymer powder.

As described later, such a formulation is preferably a filler in that the strength of the modeled object can be further improved. The filler refers to a substance that suppresses the aggregation of polymer powders due to the adhesive force between the polymer powders. By including such a filler, the fluidity of the polymer powder can be improved, and the filling property of the polymer powder tends to be improved when it is formed into a model. As a result, defects that cause mechanical properties are reduced, and the strength of the obtained modeled object tends to be further improved.

Such fillers include, for example, fused silica, crystalline silica, silica (silicon dioxide) such as amorphous silica, alumina (aluminum oxide), alumina colloid (alumina sol), alumina such as alumina white, light calcium carbonate, heavy calcium carbonate, and fine powder. Calcium carbonate, calcium carbonate such as special calcium carbonate-based filler, calcined clay such as Kasumi stone flash stone fine powder, montmorillonite, bentonite, clay (aluminum silicate powder) such as silane modified clay, talc, diatomaceous soil, Silica-containing compounds such as silica sand, crushed natural minerals such as prickly stone powder, prickly stone balloon, slate powder, and mica powder, minerals such as barium sulfate, lithopon, calcium sulfate, molybdenum disulfide, and graphite (graphite), glass fiber , Glass-based fillers such as glass beads, glass flakes, foamed glass beads, fly ash balls, volcanic glass hollow bodies, synthetic inorganic hollow bodies, monocrystalline potassium titanate, carbon fibers, carbon nanotubes, carbon hollow balls, fullerene, smokeless carbon powder , Artificial glacial stone (cryolite), titanium oxide, magnesium oxide, basic magnesium carbonate, dolomite, potassium titanate, calcium sulfite, mica, asbestos, calcium silicate, molybdenum sulfide, boron fiber, silicon carbide fiber, etc. Be done. More preferably, silica, alumina, calcium carbonate powder, glass-based filler, and titanium oxide are used. Particularly preferably, silica and alumina are mentioned in that they are hard and can contribute to strength improvement and fluidity improvement.

Commercially available products of such silica include fumed silica "AEROSIL" (registered trademark) series manufactured by Nippon Aerosil Co., Ltd., dry silica "Leolosil" (registered trademark) series manufactured by Tokuyama Corporation, and sol-gel silica powder X manufactured by Shin-Etsu Chemical Industry Co., Ltd. -24 series and the like.

The average particle size of the filler is preferably 20 nm or more and 1 μm or less. The upper limit of the average particle size of the filler is preferably 1 μm, more preferably 500 nm, more preferably 400 nm, particularly preferably 300 nm, and remarkably preferably 250 nm. The lower limit is preferably 20 nm, more preferably 30 nm, more preferably 50 nm, and particularly preferably 100 nm. When the average particle size of the filler is within the above range, the fluidity of the polymer powder can be improved and the filler can be uniformly dispersed in the polymer powder.

For the average particle size of the filler in the present invention, the cumulative curve is obtained with the total volume of the fine particles obtained by analyzing the scattered light of the laser by the dynamic light scattering method as 100%, and the cumulative curve from the small particle size side is 50. % Is the particle size (d50).

The blending amount of the filler is preferably more than 0.01 part by mass and less than 5 parts by mass with respect to 100 parts by mass of the polymer powder. The upper limit of the blending amount is preferably less than 3 parts by mass, more preferably less than 1 part by mass, further preferably less than 0.5 parts by mass, particularly preferably less than 0.3 parts by mass, and remarkably preferably less than 0.1 parts by mass. .. The lower limit of the blending amount is preferably more than 0.02 parts by mass, more preferably more than 0.03 parts by mass, and even more preferably more than 0.04 parts by mass. When the blending amount of the filler exceeds 0.01 parts by mass, the fluidity of the polymer powder is further improved and the filling property at the time of modeling is increased, so that voids that are defects in mechanical properties are less likely to occur and can be obtained. The modeled object tends to develop high strength. Further, when the blending amount of the filler is less than 5 parts by mass, sintering is not hindered by coating the surface of the polymer powder with the filler, and a high-strength molded product tends to be obtained.

In addition, in the powder bed fusion bonding method, a model is made from a part of the polymer powder used, and a large amount of polymer powder remains. Reusing the polymer powder is important in terms of cost. For that purpose, it is important not to change the properties of the polymer powder during the heating and modeling process. Such methods include, for example, a method of blending a stabilizer such as an antioxidant inside the particles to suppress thermal deterioration, a method of reducing the end groups of polyamide, and a method of suppressing changes in molecular weight during modeling. Can be mentioned. The terminal group of the polyamide is a carboxyl group or an amino group, and it is preferable to reduce the amino group from the high reactivity during molding heating. As a method for reducing these, for example, when polymerizing a polyamide, a monofunctional sealing material such as acetic acid, hexanoic acid, monocarboxylic acid such as lauric acid or benzoic acid, or monoamine such as hexylamine, octylamine, or aniline is used. The method using is used. By appropriately using such adjustment, it tends to be possible to achieve both formability and reuse.

The method for producing the polymer powder of the present invention will be described in detail.

In the method for producing the polymer powder, the monomer (B) of the polyamide is polymerized in the presence of the polymer (A) at a temperature higher than the crystallization temperature of the polyamide obtained by polymerizing the monomer (B). A method for producing a polyamide powder can be preferably used. In this method, since the polyamide monomer (B) and the polymer (A) are uniformly dissolved at the start of the polymerization, the desired particles are used after the polymerization using the low molecular weight polymer (A) important in the present invention. Polyamide powder having a diameter, a particle size distribution, a sphericity, and a polymer (A) content can be produced.

More preferably, no organic solvent is used in the manufacturing process. As a result, it tends to be possible to suppress the generation of voids in the modeled object due to the fusion of particles due to the organic solvent that cannot be completely removed in the washing or drying process. In particular, an organic solvent having a boiling point as high as 100 ° C. or higher is not preferable because it becomes difficult to remove.

In order to determine whether the polyamide monomer (B) at the start of polymerization is uniformly dissolved in the polymer (A), visually confirm that the reaction vessel is a transparent solution. When it is in a suspension or separated into two phases at the start of polymerization, it indicates that the polyamide monomer (B) and the polymer (A) are incompatible, and it is necessary to form agglomerates, vigorously stir, etc. Become. In this case, the polymerization may be started after further homogenizing the polyamide monomer (B) and the polymer (A) with water. Visually confirm that the reaction vessel is a suspension to see if the polyamide powder is precipitated after the polymerization. If it is a uniform solution at the end of polymerization, it indicates that the polyamide and the polymer (A) are uniformly compatible with each other, and agglomerates or porous powders are formed by cooling or the like.

In the method for producing the polymer powder, the polyamide monomer (B) used as a raw material for the polyamide powder is the above-mentioned monomer used as a raw material for the polyamide. As long as these monomers (B) do not impair the present invention, two or more kinds may be used, or other copolymerizable components may be contained.

The polymer (A) in the method for producing the polymer powder is the same as that described above.

After mixing these monomer (B) and polymer (A) to obtain a uniform solution, the polyamide is started by polymerization at a temperature higher than the crystallization temperature of the polyamide obtained by polymerizing the monomer (B). Produce powder. At this time, as the monomer (B) is converted to polyamide in a uniform mixed solution, the polyamide powder is uniformly induced without crystallizing. Therefore, after polymerization, the surface is solid, the surface is smooth, and the particle size distribution is narrow. Polyamide powder precipitates.

From the viewpoint of preventing the formation of a large amount of agglomerates and the like because the polymerization rate is moderate and the phase separation induced by the polymerization occurs and the particle formation occurs smoothly, while the particle formation occurs from the early stage of the polymerization. The mass ratio of the monomer (B) to the polymer (A) at the time of compounding is preferably in the range of 5/95 to 80/20. The lower limit of the mass ratio of the monomer (B) / polymer (A) is more preferably 10/90, even more preferably 20/80, and most preferably 30/70. On the other hand, as the upper limit of the mass ratio of the monomer (B) / polymer (A), 70/30 is more preferable, 60/40 is further preferable, and 50/50 is particularly preferable.

As a method for polymerizing the monomer (B) to polyamide, a known method can be used. The method depends on the type of monomer (B), but in the case of lactams, anion ring-opening polymerization using an alkali metal such as sodium or potassium or an organometallic compound such as butyllithium or butylmagnesium as an initiator. Cationic ring-opening polymerization using an acid as an initiator and hydrolysis-type ring-opening polymerization using water or the like are generally used. Since it is possible to carry out polymerization at a temperature equal to or higher than the crystallization temperature of the polyamide in which a true sphere and surface-smooth polyamide powder can be easily obtained, cation ring-opening polymerization or hydrolysis type ring-opening polymerization is preferable, and the obtained polyamide In the polymerization at a temperature equal to or higher than the crystallization temperature of the above, hydrolysis type ring-opening polymerization is more preferable from the viewpoint of suppressing the coloring of the polyamide by the initiator and the gelation and decomposition reaction by the cross-linking reaction. The method for ring-opening polymerization of lactams by hydrolysis is not limited as long as it is a known method, but it is pressurized in the presence of water to generate amino acids while promoting hydrolysis of lactams, and then water is removed. However, a method of performing ring-opening polymerization and polycondensation reaction is preferable.

In this case, since the polycondensation reaction does not occur in the presence of water, the polymerization starts at the same time when the water is discharged to the outside of the reaction tank system. Therefore, the amount of water used is not particularly limited as long as the hydrolysis of lactams proceeds, but if the total amount of the monomer (B) and the polymer (A) is 100 parts by mass, water is usually used. The amount is preferably 100 parts by mass or less. In order to improve the production efficiency of the polyamide powder, the amount of water used is more preferably 70 parts by mass or less, further preferably 50 parts by mass or less, and particularly preferably 30 parts by mass or less. In order to prevent the hydrolysis reaction of lactams from proceeding, the lower limit of the amount of water used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, further preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more. preferable. As a method for removing water (condensed water) generated by condensation during polycondensation, a known method such as a method of removing while flowing an inert gas such as nitrogen at normal pressure or a method of removing under reduced pressure is appropriately used. it can.

Further, when the monomer (B) is an amino acid, a dicarboxylic acid and a diamine, or a salt thereof, a polycondensation reaction can be used as the polymerization method. On the other hand, in the case of these monomers (B), there are combinations that do not dissolve uniformly with the polymer (A). In such a monomer (B) and the polymer (A), a polyamide powder can be produced by further adding water to the monomer (B) and the polymer (A).

When the total amount of amino acid, dicarboxylic acid, diamine and polymer (A) is 100 parts by mass, the amount of water used is preferably 10 to 200 parts by mass. From the viewpoint of preventing the particle size from becoming coarse, the amount of water used is more preferably 150 parts by mass or less, further preferably 120 parts by mass or less. On the other hand, from the viewpoint of ensuring that water functions as a solvent, the amount of water used is more preferably 20 parts by mass or more, further preferably 40 parts by mass or more.

Lactams and amino acids and / or dicarboxylic acids and diamines may be mixed and used, but in this case, water functions as a hydrolysis or solvent.

The polymerization temperature is not particularly limited as long as the polymerization of the polyamide proceeds, but the polymerization temperature can be obtained from the viewpoint of controlling the polyamide having a high crystallization temperature to be closer to a true sphere and having a smooth surface. It is preferable that the temperature is equal to or higher than the crystallization temperature of. The polymerization temperature is more preferably the crystallization temperature of the obtained polyamide + 15 ° C. or higher, further preferably the crystallization temperature of the obtained polyamide + 30 ° C. or higher, and the crystallization temperature of the obtained polyamide + 45 ° C. or higher. Is particularly preferable. From the viewpoint of preventing side reactions of polyamide such as a three-dimensional crosslinked product, coloring, and deterioration of the polymer (A), the polymerization temperature is preferably set to the melting point of the obtained polyamide + 100 ° C. or less, and the melting point of the obtained polyamide. It is more preferably + 50 ° C. or lower, further preferably the melting point of the obtained polyamide + 20 ° C. or lower, particularly preferably polymerization at the same temperature as the melting point of the obtained polyamide, and the melting point of the obtained polyamide −10 ° C. or lower. It is most preferable to do so.

The crystallization temperature of the polyamide constituting the polyamide powder is raised at a rate of 20 ° C./min from 30 ° C. to a temperature 30 ° C. higher than the heat absorption peak indicating the melting point of the polyamide under a nitrogen atmosphere using the DSC method. After that, it is held for 1 minute and shows the peak of the exothermic peak that appears when the temperature is cooled to 30 ° C. at a rate of 20 ° C./min. Further, once cooled, the apex of the endothermic peak when the temperature is further raised at 20 ° C./min is defined as the melting point of the polyamide powder.

The polymerization time can be appropriately adjusted according to the molecular weight of the polyamide powder to be obtained, but while ensuring that the polymerization proceeds to obtain the polyamide powder, side reactions and coloring of the polyamide such as a three-dimensional crosslinked product are ensured. From the viewpoint of preventing progress such as deterioration of the polymer (A) and the polymer (A), it is usually preferably in the range of 0.1 to 70 hours. The lower limit of the polymerization time is more preferably 0.2 hours or more, further preferably 0.3 hours or more, and particularly preferably 0.5 hours or more. The upper limit of the polymerization time is more preferably 50 hours or less, further preferably 25 hours or less, and particularly preferably 10 hours or less.

A polymerization accelerator may be added as long as the effect of the present invention is not impaired. Known accelerators can be used, and examples thereof include inorganic phosphorus compounds such as phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, polyphosphoric acid and alkali metal salts and alkaline earth metal salts thereof. Be done. You may use two or more kinds of these. The amount to be added can be appropriately selected, but it is preferable to add 1 part by mass or less with respect to 100 parts by mass of the monomer (B).

It is also possible to add other additives, such as surfactants for controlling the particle size of the polyamide powder, dispersants, and the stability of the polymer (A) used to modify the properties of the polyamide powder. Fillers such as antioxidants, heat stabilizers, weather resistant agents, lubricants, pigments, dyes, plasticizers, antioxidants, flame retardants, carbon black, silica, titanium dioxide, fiberglass and glass beads, carbon fiber to improve And so on. You may use two or more kinds of these. Further, two or more different substances may be used for the purpose of modifying the monomer (B) or polyamide and for the purpose of modifying the polymer (A). The amount to be added can be appropriately selected.

In the present invention, since the polyamide powder is homogeneously induced from the uniform solution, a fine powder can be produced without stirring, but even if stirring is performed in order to control the particle size and make the particle size distribution more uniform. I do not care. As the stirring device, a known device such as a stirring blade, a melt kneader, or a homogenizer can be used. For example, in the case of a stirring blade, a propeller, a paddle, a flat, a turbine, a cone, an anchor, a screw, a helical type, or the like can be used. Can be mentioned. The stirring speed depends on the type and molecular weight of the polymer (A), but from the viewpoint of uniformly transferring heat even with a large device, while preventing the liquid from adhering to the wall surface and changing the compounding ratio, etc., the stirring speed is 0 to 2,000 rpm. It is preferably in the range. The lower limit of the stirring speed is more preferably 10 rpm or more, further preferably 30 rpm or more, particularly preferably 50 rpm or more, and the upper limit of the stirring speed is more preferably 1,600 rpm or less, further preferably 1,200 rpm or less. 800 rpm or less is particularly preferable.

The present invention is characterized in that the polyamide powder is isolated from the mixture of the polyamide powder and the polymer (A) after the completion of the polymerization while the polymer (A) is melted or maintained in a solution state. Thereby, the content of the polymer (A) in the polymer powder can be reduced to less than 0.001% by mass. To isolate the polyamide powder from the mixture of the polymer powder and the polymer (A) after completion of polymerization, the mixture at the end of polymerization is discharged into a poor solvent of the polyamide powder while the polymer (A) is melted or maintained in a solution state. Isolation after addition of a poor solvent for the polymer powder in a reaction vessel containing a mixture of the polymer powder and the polymer (A) while the polymer (A) is melted or maintained in a solution state. How to do it. From the viewpoint of preventing the polyamide powders from melting and coalescing to widen the particle size distribution, the mixture is cooled to below the melting point of the polyamide powder, more preferably below the crystallization temperature, and then the mixture is placed in a poor solvent for the polyamide powder. A method of isolating by discharging into a reaction vessel or a method of adding a poor solvent of polyamide powder to the reaction vessel and isolating is preferable, and a method of adding a poor solvent of polyamide powder to the reaction vessel and isolating is more preferable. In the present invention, the discharge means an operation of extracting the contents from the reaction vessel by pressure or its own weight. When the polymer (A) is precipitated, the content of the polymer (A) is set to 0 with respect to the polymer powder as the lower limit of the temperature at which the mixture is discharged into the poor solvent of the polyamide powder or the poor solvent of the polyamide powder is added to the reaction vessel. A temperature equal to or higher than the melting point of the polymer (A) is preferable because it is difficult to reduce the content to less than .001% by mass.

The poor solvent for the polyamide powder is preferably a solvent that does not dissolve the polyamide but further dissolves the monomer (B) and the polymer (A). Such a solvent can be appropriately selected, and examples thereof include alcohols such as methanol, ethanol and isopropanol, and water, and water is preferable from the viewpoint of preventing voids and the like from being generated in the modeled object due to the organic solvent.

As the isolation method, known methods such as decompression, pressure filtration, decantation, centrifugation, and spray drying can be appropriately selected.

The polyamide powder can be washed, isolated, and dried by a known method. As a cleaning method for removing deposits and inclusions on the polyamide powder, reslurry cleaning or the like can be used, and heating may be performed as appropriate. The solvent used for washing is not limited as long as it is a solvent that does not dissolve the polyamide powder but dissolves the monomer (B) and the polymer (A), and water is preferable from the viewpoint of economy. Isolation can be appropriately selected from reduced pressure, pressure filtration, decantation, centrifugation, spray drying and the like. By main washing and isolation, the polymer (A) is removed to less than 0.001% by weight based on the polyamide powder. Drying is preferably carried out at a temperature equal to or lower than the melting point of the polyamide powder, and the pressure may be reduced. Air drying, hot air drying, heat drying, vacuum drying, freeze drying, etc. are selected.

Additional heat treatment may be applied to the obtained polyamide powder as long as the effects of the present invention are not impaired. As a heat treatment method, a known method can be used, and a normal pressure heat treatment using an oven or the like, a reduced pressure heat treatment using a vacuum dryer or the like, and a pressure heat treatment in which heat treatment is performed together with water in a pressure vessel such as an autoclave can be appropriately selected. By heat treatment, it is possible to control the molecular weight, crystallinity, and melting point of the polyamide within a desired range.

The polymer powder of the present invention is a material useful for producing a three-dimensional model by a powder bed fusion bonding method.

Powder bed melt-bonding method The manufacturing of a modeled product by additive manufacturing is a thin layer forming process in which polymer powder is developed into a thin layer, and this thin layer is irradiated with laser light in a shape corresponding to the cross-sectional shape of the object to be modeled. A selective laser sintering method in which the cross-section forming steps of bonding the polymer powders are sequentially repeated, or a thin-layer forming step of developing the polymer powder into a thin layer, and the thin layers correspond to the cross-sectional shape of the object to be modeled. Powder bed melt bonding by selective absorption (or suppression) sintering method in which a printing process of printing an energy absorption promoter or an energy absorption inhibitor on a shape and a cross-sectional forming process of bonding polymer powder using electromagnetic radiation are sequentially repeated. Method This can be done by a method of manufacturing a layered model. The electromagnetic radiation used in the selective absorption (suppression) sintering may be any kind as long as it does not impair the quality of the polymer powder or the modeled object, but it is relatively inexpensive and energy suitable for modeling can be obtained. Therefore, infrared rays are preferable. Also, electromagnetic radiation may or may not be coherent.

Energy absorption accelerator is a substance that absorbs electromagnetic radiation. Such substances include carbon black, carbon fibers, copper hydroxyphosphate, near-infrared absorbing dyes, near-infrared absorbing pigments, metal nanoparticles, polythiophene, poly (p-phenylene sulfide), polyaniline, poly (pyrrole), etc. Consists of polyacetylene, poly (p-phenylene vinylene), polyparaphenylene, poly (styrene sulfonate), poly (3,4-ethylenedioxythiophene) -poly (styrenephosphonate) p-diethylaminobenzaldehydediphenylhydrazone, or a combination thereof. Examples thereof include conjugated polymers, and these may be used alone or in combination of two or more.

Energy absorption inhibitor is a substance that does not easily absorb electromagnetic radiation. Examples of such substances include substances that reflect particle electromagnetic radiation such as titanium, heat insulating powders such as mica powder and ceramic powder, and water, which may be used alone or in combination of two or more. ..

These selective absorbents or selective inhibitors may be used alone or in combination.

Selective absorbent or selective inhibitor In the step of printing into a shape corresponding to the cross-sectional shape of the object to be modeled, a known method such as inkjet can be used. In this case, the selective absorbent or selective inhibitor may be used as it is, or may be dispersed or dissolved in a solvent.

Hereinafter, the present invention will be described based on examples.

(1) D50 particle size and D90 / D10
To a laser diffraction type particle size distribution meter measuring device (Microtrack MT3300EXII) manufactured by Nikkiso Co., Ltd., a dispersion liquid in which about 100 mg of polyamide powder is previously dispersed in about 5 mL of deionized water is added until it reaches a measurable concentration, and measurement is performed. After ultrasonic dispersion at 30 W for 60 seconds in the apparatus, the particle size at which the cumulative frequency from the small particle size side of the particle size distribution measured in the measurement time of 10 seconds is 50% was defined as the D50 particle size. .. D90 / D10 showing the particle size distribution has a particle size (D90) in which the cumulative frequency from the small particle size side of the particle size distribution measured by the above method is 90%, and the cumulative frequency from the small particle size side is 10%. The value was divided by the particle size (D10). The refractive index at the time of measurement was 1.52, and the refractive index of the medium (deionized water) was 1.333.

(2) Sphericality of polymer powder The sphericity of polyamide powder is determined by observing 30 particles at random from a scanning electron microscope (manufactured by JEOL Ltd., scanning electron microscope: JSM-6301NF). It was calculated from the minor axis and the major axis according to the following formula.

Note that S: sphericity, a: major axis, b: minor axis, n: number of measurements 30.

(3) BET specific surface area According to Japanese Industrial Standards (JIS standard) JIS R1626 (1996) "Method of measuring specific surface area by gas adsorption BET method", about 0.2 g of polyamide powder was put into a glass cell using BELSORP-max manufactured by Nippon Bell. After degassing under reduced pressure at 80 ° C. for about 5 hours, the krypton gas adsorption isotherm at the temperature of liquid nitrogen was measured and calculated by the BET method.

(4) Crystallization temperature and melting point of polymer powder Using a differential scanning calorimeter (DSCQ20) manufactured by TA Instruments, the temperature is 20 ° C. from 30 ° C. to a temperature 30 ° C. higher than the heat absorption peak indicating the melting point of polyamide under a nitrogen atmosphere. The crystallization temperature was defined as the peak of the exothermic peak that appeared when the temperature was raised at a rate of / min and then held for 1 minute and the temperature was cooled to 30 ° C. at a rate of 20 ° C./min. The melting point was defined as the endothermic peak when the temperature was further raised at 20 ° C./min after cooling. The amount of polyamide powder required for the measurement was about 8 mg.

(5) Molecular Weight of Polyamide Constituting Polymer Powder The molecular weight of the weight average molecular weight of the polyamide was calculated by using a gel permeation chromatography method and comparing it with a calibration curve using polymethylmethacrylate. The measurement sample was prepared by dissolving about 3 mg of polyamide powder in about 3 g of hexafluoroisopropanol.
Equipment: Waters e-Alliance GPC system
Column: Showa Denko HFIP-806M x 2
Mobile phase: 5 mmol / L Sodium trifluoroacetate / Hexafluoroisopropanol Flow rate: 1.0 ml / min
Temperature: 30 ° C
Detection: Differential refractometer.

(6) Molecular Weight of Polymer (A) The weight average molecular weight of the polymer (A) was calculated by using a gel permeation chromatography method and comparing it with a calibration curve using polyethylene glycol. The measurement sample was prepared by dissolving about 3 mg of the polymer (A) in about 6 g of water.
Equipment: LC-10A series manufactured by Shimadzu Corporation Column: TSKgelG3000PWXL manufactured by Tosoh Corporation
Mobile phase: 100 mmol / L sodium chloride aqueous solution Flow rate: 0.8 ml / min
Temperature: 40 ° C
Detection: Differential refractometer.

(7) Content of Polymer (A) 1000 g of water was added to 1000 g of polyamide powder, heated to 80 ° C., and then water was isolated. After removing the water, the obtained solid substance was dissolved in 5 g of water, and the weight of the polymer (A) was measured using the same gel permeation chromatography method as in (7). The content (% by mass) of the polymer (A) was calculated by dividing the weight of the polymer (A) by the amount of the polyamide powder.

(8) Measurement of angle of repose Using a multi-tester MT-1 manufactured by Seishin Enterprise, 100 g of polyamide powder was dropped from the funnel onto a flat plate, and the angle of repose was measured from the angle between the volume of the mountain slope and the plate. If the angle of repose was 40 degrees or less, it was evaluated as "good", and if it was over 40 degrees, it was evaluated as "bad".

(9) Surface Roughness of the Modeled Object Using an optical microscope (VHX-5000) manufactured by KEYENCE CORPORATION and an objective lens of VH-ZST (ZS-20), the surface of the modeled object was observed at a magnification of 200 times. After three-dimensional imaging of the unevenness of the surface of the modeled object in the automatic composition mode using the software (system version 1.04) attached to the device, the height profile of the cross section is acquired over a length of 1 mm or more, and the surface is roughened by the arithmetic mean. The degree Ra was calculated. It is shown that the smaller the surface roughness Ra, the better the smoothness of the surface. In addition, Ra of 10 or less was evaluated as "good", and Ra of more than 10 was evaluated as "bad".

(10) Measurement of bending strength The bending strength of a three-dimensional model produced using polymer powder is determined by using a powder bed melt-bonding method 3D printer (Aspect Co., Ltd. powder bed melt-bonding device RaFaElII 150C-HT). A test piece having a width of 10 mm, a length of 80 mm, and a thickness of 4 mm was prepared and measured using a Tensilon universal tester (TENSIRON TRG-1250, manufactured by A & D Co., Ltd.). According to JIS K7171 (2008), a three-point bending test was measured under the conditions of a distance between fulcrums of 64 mm and a test speed of 2 mm / min, and the bending strength was measured. The measurement temperature was room temperature (23 ° C.), the number of measurements was n = 5, and the average value was calculated.

[Example 1]
Aminododecanoic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 300 g as a polyamide monomer (B) and polyethylene glycol (Wako Pure Chemical Industries, Ltd.) as a polymer (A) in an autoclave with a 3 L helical ribbon type stirring blade. 20,000 primary polyethylene glycol manufactured by the company, 700 g of weight average molecular weight 18,600) and 1000 g of water were added to form a uniform solution, which was then sealed and replaced with nitrogen. Then, the stirring speed was set to 30 rpm and the temperature was raised to 210 ° C. At this time, ^{after the pressure of the system reached 10 kg / cm 2} , the pressure was controlled while slightly releasing water vapor so as to maintain the pressure at 10 kg / cm ^2. After the temperature reached 210 ° C., the pressure was released at a rate of ^{0.2 kg / cm 2 · min.} Then, the temperature was maintained for 1 hour while flowing nitrogen to complete the polymerization, and the mixture of the polymer powder and polyethylene glycol was discharged into a water bath of 2000 g while the polyethylene glycol was kept in a molten state to obtain a slurry. After the slurry was sufficiently homogenized by stirring, filtration was performed, 2000 g of water was added to the filter medium, and the slurry was washed at 80 ° C. Then, the slurry liquid from which the agglomerates had been removed by passing through a 200 μm sieve was filtered again, and the isolated filter product was dried at 80 ° C. for 12 hours to prepare 240 g of polyamide 12 powder. The melting point of the obtained powder was 178 ° C., which was the same as that of polyamide 12, the crystallization temperature was 147 ° C., and the molecular weight was 12,000. The D50 particle size was 53 μm, the D90 / D10 was 2.5, the sphericity was 98, the polyethylene glycol content was 0.0006% by mass, and the angle of repose was 33 degrees. The BET specific surface area was 0.16 m ² / g and R = 1.3.

Using 1.5 kg of this polyamide powder, a three-dimensional model was manufactured using a powder bed fusion coupling device (RaFaElII 150C-HT) manufactured by Aspect Co., Ltd. The setting conditions were a layer average thickness of 0.1 mm, a 60 WCO ₂ laser, and a laser scanning space of 0.1 mm. The temperature was set so that the component floor temperature was −15 ° C. from the melting point and the supply tank temperature was the crystallization temperature −5 ° C. The surface roughness Ra of the obtained modeled product was 9 μm, the bending strength of the modeled product was 63 MPa, and the appearance of the modeled product was good with no voids. The characteristics are shown in Table 1.

[Example 2]
The polyamide monomer (B) was changed to 200 g of aminododecanoic acid, and the polymer (A) was changed to 800 g of polyethylene glycol having a different molecular weight (primary polyethylene glycol manufactured by Wako Pure Chemical Industries, Ltd., 6,000, molecular weight 7,700). Polyamide 12 powder was prepared in the same manner as in Example 1 except for the above. Table 1 shows the characteristics of the obtained powder and the modeled product. A scanning electron micrograph of the polyamide 12 powder is shown in FIG.

[Example 3]
The polyamide monomer (B) was changed to 100 g of aminododecanoic acid, and the polymer (A) was changed to 900 g of polyethylene glycol having a different molecular weight (primary polyethylene glycol manufactured by Wako Pure Chemical Industries, Ltd., 2,000, molecular weight 2,300). Polyamide 12 powder was prepared in the same manner as in Example 1 except for the above. Table 1 shows the characteristics of the obtained powder and the modeled product.

[Example 4]
Polyamide 11 powder was prepared in the same manner as in Example 2 except that aminododecanoic acid was changed to aminoundecanoic acid as the polyamide monomer (B). Table 1 shows the characteristics of the obtained powder and the modeled product.

[Example 5]
Polyamide 6 powder was prepared in the same manner as in Example 2 except that aminododecanoic acid was changed to aminocaproic acid as the polyamide monomer (B). Table 1 shows the characteristics of the obtained powder and the modeled product. A scanning electron micrograph of the polyamide 6 powder is shown in FIG.

[Example 6]
Adipic acid 90 g (manufactured by Tokyo Kasei Kogyo Co., Ltd.), hexamethylenediamine 50% aqueous solution 110 g (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as the polyamide monomer (B), and the polymerization temperature was changed to 230 ° C. Made a polyamide 66 powder in the same manner as in Example 2. Table 1 shows the characteristics of the obtained powder and the modeled product.

[Example 7]
Polyamide in the same manner as in Example 2 except that aminododecanoic acid was changed to 108 g of sebacic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 92 g of diaminodecane (manufactured by Tokyo Chemical Industry Co., Ltd.) as the monomer (B) of the polyamide. 1010 powder was prepared. Table 1 shows the characteristics of the obtained powder and the modeled product.

[Example 8]
The same method as in Example 2 except that aminododecanoic acid was changed to 86 g of dodecane diic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 114 g of diaminodecane (manufactured by Tokyo Chemical Industry Co., Ltd.) as the monomer (B) of the polyamide. Polyamide 1012 powder was prepared. Table 1 shows the characteristics of the obtained powder and the modeled product.

[Example 9]
To 100 parts by mass of the polyamide 12 powder produced by the same method as in Example 2, 0.05 mass by mass of trimethylsilylated amorphous silica (X-24-9500 manufactured by Shin-Etsu Chemical Co., Ltd.) having an average particle size of 170 nm was added as a filler. Partially added. Table 1 shows the characteristics of the obtained powder and the modeled product.

[Example 10]
0.05 mass by mass of trimethylsilylated amorphous silica (X-24-9500 manufactured by Shin-Etsu Chemical Co., Ltd.) having an average particle size of 170 nm as a filler with respect to 100 parts by mass of the polyamide 6 powder produced by the same method as in Example 5. Partially added. Table 1 shows the characteristics of the obtained powder and the modeled product.

[Example 11]
0.08 mass by mass of trimethylsilylated amorphous silica (X-24-9500 manufactured by Shin-Etsu Chemical Co., Ltd.) having an average particle size of 170 nm as a filler with respect to 100 parts by mass of the polyamide 6 powder produced by the same method as in Example 5. Partially added. Table 2 shows the characteristics of the obtained powder and the modeled product.

[Example 12]
0.4 mass by mass of trimethylsilylated amorphous silica (X-24-9500 manufactured by Shin-Etsu Chemical Co., Ltd.) having an average particle size of 170 nm as a filler with respect to 100 parts by mass of the polyamide 6 powder produced by the same method as in Example 5. Partially added. Table 2 shows the characteristics of the obtained powder and the modeled product.

[Example 13]
To 100 parts by mass of the polyamide 6 powder produced by the same method as in Example 5, 0.8 parts by mass of α-alumina (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) having an average particle size of 500 nm was added as a filler. Table 2 shows the characteristics of the obtained powder and the modeled product.

[Example 14]
To 100 parts by mass of the polyamide 6 powder produced by the same method as in Example 5, 2.5 parts by mass of α-alumina (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) having an average particle size of 1 μm was added as a filler. Table 2 shows the characteristics of the obtained powder and the modeled product.

[Example 15]
Conducted except that 198 g of aminohexanoic acid as the polyamide monomer (B), 800 g of polyethylene glycol as the polymer (A), 1000 g of water, and 2 g of benzoic acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) were added to the autoclave. Polyamide 6 powder was prepared in the same manner as in Example 5. Table 2 shows the characteristics of the obtained powder and the modeled product.

[Example 16]
In an autoclave, 198.6 g of aminohexanoic acid as a polyamide monomer (B), 800 g of polyethylene glycol as a polymer (A), 1000 g of water, and 1.4 g of IRGANOX1098 (manufactured by BASF Japan Co., Ltd.) as an antioxidant are blended. Polyamide 6 powder was prepared in the same manner as in Example 5 except for the above. Table 2 shows the characteristics of the obtained powder and the modeled product.

[Example 17]
0.08 mass by mass of trimethylsilylated amorphous silica (X-24-9500 manufactured by Shin-Etsu Chemical Co., Ltd.) having an average particle size of 170 nm as a filler with respect to 100 parts by mass of the polyamide 6 powder produced by the same method as in Example 15. Partially added. Table 2 shows the characteristics of the obtained powder and the modeled product.

[Example 18]
Polyamide 6 powder was prepared in the same manner as in Example 10 except that aminohexanoic acid was changed to ε-caprolactam as the polyamide monomer (B). Table 2 shows the characteristics of the obtained powder and the modeled product.

[Comparative Example 1]
Example 1 except that the polyamide monomer (B) was changed to 400 g of aminododecanoic acid and the polymer (A) was changed to 600 g of polyethylene glycol having a different molecular weight (polyethylene oxide 100,000 made by Aldrich, weight average molecular weight 89,000). Polyamide 12 powder was prepared in the same manner as in the above. Table 2 shows the characteristics of the obtained powder and the modeled product.

[Comparative Example 2]
Polyamide 12 ('VESTAMID'® L1600) 50 g, polyethylene glycol (Aldrich polyethylene oxide 100,000, weight average molecular weight 89,000) 150 g in a laboplast mill (manufactured by Toyo Seiki) at a temperature of 192 ° C., screw rotation It was melt-kneaded at several 50 rpm, and the obtained mixture was dissolved in 3.6 L of water. The powder was separated by filtration from this dispersion, washed with water multiple times, and dried at 80 ° C. for 6 hours. Table 2 shows the characteristics of the obtained powder and the modeled product.
[Comparative Example 3]
Polyamide 6 is a method of isolating the polyamide powder after solidifying the mixture of the polyamide powder and the polymer (A) after completion of polymerization by cooling in the same manner as described in Example 1 of WO2018 / 207728. A powder was prepared. The obtained powder contained 0.0326% of polyethylene glycol, had an angle of repose of 51 degrees and had low fluidity, and could not form a three-dimensional model by a powder bed fusion bonding device.

Since the polymer powder of the present invention has high fluidity and excellent surface smoothness can be obtained when the polyamide powder is used as a model, it is a three-dimensional model produced by a powder bed fusion bonding method. It can be suitably used for objects.

Claims (13)

1. A polymer powder for producing a three-dimensional model by a powder bed melt bonding method. The polymer powder is composed of polyamide, has a D50 particle size of 1 to 100 μm, a sphericity of 80 or more, and a weight average molecular weight. One or more polymers (A) selected from the group consisting of polyethylene glycols, polypropylene glycols, polytetramethylene glycols, polyethylene glycol-polypropylene glycol copolymers, and alkyl ethers having an amount of 20,000 or less are applied to the polymer powder. A polymer powder for producing a three-dimensional molded product, which comprises less than 0.001% by mass.
2. The polymer powder for producing a three-dimensional model according to claim 1, wherein the polymer powder has a sphericity of 90 or more.
3. The polymer powder for producing a three-dimensional model according to claim 1 or 2, wherein D90 / D10 indicating the particle size distribution of the polymer powder is less than 3.
4. The polymer powder for producing a three-dimensional model according to any one of claims 1 to 3, wherein the polymer powder does not contain an organic solvent.
5. The three-dimensional model according to any one of claims 1 to 4, wherein the ratio of the theoretical surface area calculated from the BET specific surface area and the number average particle diameter of the polymer powder is 5 or less. Polymer powder.
6. The polymer powder for producing a three-dimensional model according to any one of claims 1 to 5, wherein the polymer powder contains a filler.
7. The polymer powder for producing the three-dimensional model according to claim 6, wherein the filler is silica.
8. The polymer powder for producing a three-dimensional model according to claim 6 or 7, wherein the filler is contained in an amount of more than 0.01 parts by mass and less than 5 parts by mass with respect to 100 parts by mass of the polymer powder.
9. The polymer powder for producing a three-dimensional model according to any one of claims 1 to 8, wherein the polymer contains polyamide 6, polyamide 66, or a copolymer thereof.
10. The polymer for producing a three-dimensional model according to any one of claims 1 to 8, wherein the polymer contains a polyamide 11, a polyamide 12, a polyamide 1010, a polyamide 1012, or a copolymer thereof. Powder.
11. A method for producing a three-dimensional model by a powder bed melt-bonding method using the polymer powder according to any one of claims 1 to 10.
12. A three-dimensional model obtained by a powder bed melt-bonding method using the polymer powder according to any one of claims 1 to 10.
13. A method for producing a polymer powder composed of polyamide by polymerizing a polyamide monomer (B) in the presence of a polymer (A) at a temperature equal to or higher than the crystallization temperature of the obtained polyamide. A method for producing a polyamide powder, which comprises isolating a polymer powder from a mixture of the polymer (A) while maintaining the molten or solution state of the polymer (A).

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