Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B1/00—Producing shaped prefabricated articles from the material
  • B28B1/30—Producing shaped prefabricated articles from the material by applying the material on to a core or other moulding surface to form a layer thereon
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
  • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
  • C04B35/581—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on aluminium nitride

Definitions

• the present invention relates to a powder composition and a method for producing a three-dimensional object.
• Additive manufacturing is a technology used in three-dimensional modeling methods such as 3D printers to create three-dimensional shapes by attaching modeling materials, and has been rapidly gaining popularity in recent years.
• Additive manufacturing methods using additive manufacturing technology can be classified into several methods based on the type of material and modeling method (e.g., ISO 17296-2:2015).
• One of these methods is powder bed fusion (PBF).
• powder bed fusion three-dimensional objects are obtained by layering and melting powder material. The properties of the three-dimensional objects obtained in powder bed fusion depend on the powder material.
• Patent Document 1 discloses a molding powder used in powder additive manufacturing, which is made of a powder containing a ceramic and a binder.
• Patent Document 2 discloses a molding material used in powder additive manufacturing, which is made of an inorganic powder containing at least a resin material in part.
• Additive manufacturing technology is expected to be applied in a variety of fields because it can easily produce three-dimensional objects.
• composite compositions of resin and aluminum nitride which has high thermal conductivity, have been used for heat dissipation applications.
• additive manufacturing technology can easily produce objects, it is expected that it can be used in a variety of fields where high thermal conductivity is required.
• Patent Documents 1 and 2 do not describe obtaining a molded body with high thermal conductivity, nor do they suggest such an issue. Furthermore, when a molded body is obtained using a powder composition containing aluminum nitride powder and a resin, it is unclear what physical properties, including thermal conductivity, the molded body will have depending on the type of resin.
• One aspect of the present invention aims to create a powder composition that can produce a molded product with high thermal conductivity.
• one embodiment of the present invention provides a powder composition comprising aluminum nitride powder and polyamide powder, with the aluminum nitride powder content being 70% by mass or more and 95% by mass or less.
• One aspect of the present invention makes it possible to realize a powder composition that can produce a molded product with high thermal conductivity.
• a powder composition according to one embodiment of the present invention contains aluminum nitride powder and polyamide powder, and the content of the aluminum nitride powder is 70% by mass or more and 95% by mass or less.
• the term "powder composition” refers to the powder composition according to one embodiment of the present invention, unless otherwise specified.
• the powder composition is preferably used as a material for molding compacts, and in particular as a material for forming three-dimensional objects using additive manufacturing methods.
• the aluminum nitride powder is composed of a plurality of aluminum nitride particles formed from aluminum nitride.
• the content of aluminum nitride powder in the powder composition is 70% by mass or more and 95% by mass or less, with the entire powder composition being 100% by mass. This configuration effectively improves the thermal conductivity of a molded body formed using the powder composition. From the perspective of achieving excellent thermal conductivity in the molded body, the content of aluminum nitride powder may be 80% by mass or more, or even 90% by mass or more.
• the aluminum nitride powder preferably has an average particle size of 20 ⁇ m or more and 60 ⁇ m or less. Powder compositions containing aluminum nitride powder with such an average particle size tend to have good flowability.
• the powder composition When the powder composition is layered and molded using additive manufacturing, for example, the powder composition is spread in a layer of uniform thickness over the entire surface of the molded area of each layer. In this case, the better the fluidity of the powder composition, the easier it is to layer the powder composition to a uniform thickness. If the average particle size of the aluminum nitride powder is within the above-mentioned range, the fluidity of the powder composition is improved, and the powder composition can be easily layered to a uniform thickness.
• the thickness of each layer formed from the powder composition is generally about 100 ⁇ m.
• the average particle size of the aluminum nitride powder is preferably smaller than the thickness of each layer, and is preferably 60 ⁇ m or less. However, if the average particle size is too small, the fluidity of the powder composition will deteriorate, so the average particle size of the aluminum nitride powder is preferably 20 ⁇ m or more.
• the average particle size of aluminum nitride powder is the particle size (median diameter) at the cumulative 50% value on a volume basis in the particle size distribution measured by laser diffraction scattering.
• Aluminum nitride powder preferably has an average circularity of 0.8 or more, and more preferably 0.9 or more. Generally, the closer a particle's circularity is to 1.0, the closer it is to a perfect sphere. Aluminum nitride powder with an average circularity of 0.8 or more can be said to be composed of approximately spherical aluminum nitride particles.
• the powder composition contains 70% by mass or more of aluminum nitride powder.
• the aluminum nitride powder which accounts for a large portion of the powder composition, has an average circularity of 0.8 or more. Spherical powder with a high average circularity exhibits good fluidity, thereby improving the fluidity of the powder composition.
• the circularity of particles contained in aluminum nitride powder can be calculated using the following formula (1), where S is the projected area of the imaged particle and L is the perimeter.
• the average circularity of the aluminum nitride powder may be the number average value of the circularity of a plurality of particles contained in the aluminum nitride powder.
• the polyamide powder is composed of a plurality of polyamide particles formed from polyamide.
• the polyamide used as the raw material for the polyamide powder may be an aliphatic polyamide such as nylon, or an aromatic polyamide such as aramid.
• polyamides include nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 612, nylon 6T, nylon 6I, nylon 9T, and nylon M5T. Of these, nylon 6, nylon 11, or nylon 12 is preferred, and nylon 12 is even more preferred.
• the polyamide may be any one of these, or may contain two or more types.
• aluminum nitride powder is effective in improving thermal conductivity in compacts made from a powder composition containing aluminum nitride powder.
• the surface of aluminum nitride powder is oxidized, resulting in the presence of hydroxyl groups.
• the polyamide that makes up the polyamide powder has amide groups that have a high affinity for the hydroxyl groups present on the surface of the aluminum nitride powder.
• the high affinity between the resin and aluminum nitride powder allows the aluminum nitride powder to disperse appropriately, making it easier to form thermal conduction paths between the aluminum nitride powder particles in the compact. It is believed that the formation of these thermal conduction paths results in excellent thermal conductivity in the compact.
• the polyamide powder preferably has an average particle size of 20 ⁇ m or more and 60 ⁇ m or less. Powder compositions containing polyamide powder with such an average particle size tend to have good flowability. The reason for this is as explained above regarding the average particle size of aluminum nitride powder.
• the average particle size of polyamide powder is the particle size (median diameter) at which the cumulative 50% value is reached on a volume basis in the particle size distribution measured by laser diffraction scattering.
• the average particle size of the aluminum nitride powder be 20 ⁇ m or more and 60 ⁇ m or less, and that the average particle size of the polyamide powder be 20 ⁇ m or more and 60 ⁇ m or less.
• the average particle size of the aluminum nitride powder and the average particle size of the polyamide powder do not differ significantly, thereby achieving good fluidity for the powder composition.
• the more uniform the particle size of the powder contained in a powder composition the better the fluidity. This is thought to be because when powders with large and small particle sizes are mixed, the small particle size powder gets into the gaps between the large particle size powders and inhibits the flow of the large particle size powder, reducing the fluidity of the powder as a whole. If the average particle size of the aluminum nitride powder and the average particle size of the polyamide powder are close in value, the powder composition will have good fluidity.
• the ratio of the average particle size of the polyamide powder to the average particle size of the aluminum nitride powder is preferably in the range of 0.5 to 2.0, and more preferably in the range of 0.7 to 1.4.
• the content of polyamide powder in the powder composition according to one embodiment of the present invention is not particularly limited, but from the perspective of ease of molding in additive manufacturing methods, it is preferably 3% by mass or more, and more preferably 5% by mass or more.
• the powder composition may contain other powders in addition to aluminum nitride powder and polyamide powder.
• the other powders may be, for example, inorganic or organic powders.
• the inorganic powders may be, for example, powders of glass beads, glass fibers, carbon fibers, or alumina.
• the organic powders may be powders of resins other than polyamides or cellulose fibers.
• the resins other than polyamides are not particularly limited, but are preferably polar resins such as polyurethane and polyether ether ketone, or may be non-polar resins such as polyolefins.
• the content of the other powders in the powder composition may be, for example, 25% by mass or less, 10% by mass or less, or 1% by mass or less.
• the average particle size of the other powders it is preferable that the average particle size of the other powders be close to that of the aluminum nitride powder or polyamide powder.
• the average particle size of other powders may be measured in the same manner as the average particle size of aluminum nitride powder and polyamide powder.
• a method for manufacturing a three-dimensionally shaped object according to one embodiment of the present invention is a method for manufacturing a three-dimensionally shaped object by an additive manufacturing method using the above-described powder composition.
• the term "method for manufacturing a three-dimensionally shaped object” refers to the method for manufacturing a three-dimensionally shaped object according to one embodiment of the present invention, unless otherwise specified.
• Additive manufacturing is a technology for creating three-dimensional shapes by applying a modeling material.
• a method for creating three-dimensional objects using additive manufacturing can be carried out, for example, using a 3D printer.
• Additive manufacturing can be classified into several methods based on the type of material and manufacturing method used (e.g., ISO 17296-2:2015). Examples of such additive manufacturing methods include Powder Bed Fusion (PBF), Liquid Phase Photo Polymerization, Binder Jetting, Material Jetting, Material Extrusion, Directed Energy Deposition, and Sheet Lamination. There are also known additive manufacturing methods that are not classified according to ISO 17296-2:2015.
• PPF Powder Bed Fusion
• Liquid Phase Photo Polymerization Binder Jetting
• Material Jetting Material Jetting
• Material Extrusion Material Extrusion
• Directed Energy Deposition Directed Energy Deposition
• Sheet Lamination Sheet Lamination
• the preferred method for manufacturing three-dimensional objects is powder additive manufacturing.
• Powder additive manufacturing is a method for creating the desired shape by repeatedly laying out layers of raw material powder for creation and irradiating the area to be created with a laser to melt, solidify, or sinter the raw material powder.
• Powder additive manufacturing methods include the SLS (Selective Laser Sintering) method, a type of powder bed fusion method classified in ISO 17296-2:2015.
• the powder composition according to one embodiment of the present invention contains polyamide powder, which is a thermoplastic resin. Therefore, it is possible to mold the polyamide resin by melting and solidifying it with a laser, for example, and it is also possible to mold the powder composition by partially melting and solidifying the surface of the powder composition.
• the powder composition according to one embodiment of the present invention can be suitably used as a material for forming three-dimensional objects by additive manufacturing methods such as powder layer modeling. For example, by spreading the powder composition according to one embodiment of the present invention in layers and irradiating the area to be formed with a laser to melt and solidify the resin, a resin composition with a desired shape and high thermal conductivity can be easily produced. In other words, by using a powder composition containing aluminum nitride powder according to one embodiment of the present invention and polyamide powder as a material, three-dimensional objects with excellent thermal conductivity can be easily produced.
• the thermal conductivity of a three-dimensional object obtained by additive manufacturing using the powder composition is preferably 1.0 W/m ⁇ K or higher, and more preferably 1.3 W/m ⁇ K or higher. There is no particular upper limit to the thermal conductivity, and the higher the better, but it is usually 5.0 W/m ⁇ K or lower. Furthermore, the method for producing a three-dimensional object by additive manufacturing using the powder composition can also achieve good strength, density, and appearance of the molded product.
• Additive manufacturing methods are well suited for rapid prototyping, on-demand production of jigs and tools, custom production of parts for actual products, and small-lot production.
• the three-dimensional objects obtained by additive manufacturing may require high thermal conductivity.
• three-dimensional objects that require high thermal conductivity include thermal sinks for drones or electric vehicles, heat exchangers and heat recovery systems for solar hot water heaters, heat sinks for LEDs (Light Emitting Diodes), molds for vacuum forming, and functional parts that combine thermal conductivity and electromagnetic wave shielding properties.
• the powder composition according to one embodiment of the present invention and the method for manufacturing a three-dimensional object using the powder composition can be suitably used to manufacture three-dimensional objects that require such high thermal conductivity.
• a powder composition according to a first aspect of the present invention contains aluminum nitride powder and polyamide powder, and the content of the aluminum nitride powder is 70% by mass or more and 95% by mass or less.
• the average particle size of the aluminum nitride powder may be 20 ⁇ m or more and 60 ⁇ m or less, and the average particle size of the polyamide powder may be 20 ⁇ m or more and 60 ⁇ m or less.
• the aluminum nitride powder in aspect 1 or 2, may have an average circularity of 0.8 or more.
• the powder composition according to aspect 4 of the present invention may be used as a material for forming a three-dimensional object by additive manufacturing in any of aspects 1 to 3 above.
• a method for manufacturing a three-dimensional object according to aspect 5 of the present invention is a method for manufacturing a three-dimensional object by additive manufacturing using the powder composition according to any one of aspects 1 to 4.
• a method for manufacturing a three-dimensional object according to aspect 6 of the present invention may be the same as that of aspect 5, except that the additive manufacturing method is a powder additive manufacturing method.
• Aspect 7 of the present invention relates to the use of a powder composition in additive manufacturing, which comprises aluminum nitride powder and polyamide powder, and the aluminum nitride powder content is 70% by mass or more and 95% by mass or less.
• Thermoplastic resin powder and aluminum nitride powder (average particle size 30 ⁇ m) were mixed and stirred in a roller mixer for 2 hours, after which the mixed powder was passed through an ultrasonic sieve (mesh opening 250 ⁇ m) to obtain a powder composition according to the example or comparative example.
• a three-dimensional object was created by powder additive manufacturing using a 3D printer (Sinterit LISA PRO, manufactured by SINTERIT).
• thermoplastic resin powder nylon 12 (PA12, SINTERIT PA12 smooth, average particle size 40 ⁇ m) was used as the thermoplastic resin powder.
• polypropylene PP, Bamberger Polymers Bapolene 4082NA, average particle size 22 ⁇ m
• Tokuyama Aluminum Nitride Powder HFS-30 average particle size 30 ⁇ m, average circularity 0.94 was used as the aluminum nitride powder.
• the contents of thermoplastic resin powder and aluminum nitride powder in the powder composition are shown in Table 1 below.
• the average particle size of aluminum nitride powder was measured as follows. Aluminum nitride powder was dispersed in water at a concentration of 0.2% by mass, and then irradiated with ultrasonic waves at approximately 200 W for 2 minutes. The volume frequency distribution (particle size distribution) of particle size was measured using a laser diffraction/scattering particle size distribution analyzer (MICROTRACK-MT3300EXII, manufactured by Microtrack Bell Co., Ltd.). In the obtained particle size distribution, the volume frequency was accumulated from the smallest particle size, and the particle size (median diameter) at which the accumulated value reached 50% was taken as the average particle size.
• MICROTRACK-MT3300EXII laser diffraction/scattering particle size distribution analyzer
• the average particle size of the thermoplastic resin powder was measured using a laser diffraction/scattering particle size distribution analyzer (Beckman Coulter: LS 13 320) equipped with a tornado dry powder module, in accordance with ISO 13320.
• the volume frequency was accumulated from the smallest particle size, and the particle size (median diameter) at which the accumulated value reached 50% was taken as the average particle size.
• the average circularity of the aluminum nitride powder was calculated using formula (1) by measuring the area and perimeter of the two-dimensional projection of 20,000 particles using a Malvern Morphologi G3.
• the thermal conductivity of the resulting three-dimensional object was measured using a thermal conductivity measuring device (TRIDENT, manufactured by C-Therm Technologies) that utilizes an improved unsteady plane heat source and a Pyroceram calibration standard, in accordance with ASTM D7984.
• TRIDENT manufactured by C-Therm Technologies
• PA12 stands for polyamide 12 (nylon 12)
• PP stands for polypropylene
• AlN stands for aluminum nitride powder.
• the three-dimensionally molded objects of Examples 1 and 2 had a thermal conductivity of 1.0 W/m ⁇ K or higher, demonstrating good thermal conductivity.
• the three-dimensionally molded object of Comparative Example 1 had a thermal conductivity of less than 1.0 W/m ⁇ K, which was approximately half that of the three-dimensionally molded objects of Examples 1 and 2.

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• 2025
  • 2025-01-16 JP JP2025520765A patent/JP7719327B1/ja active Active
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