JP6958217B2 - Manufacturing method of resin powder for three-dimensional modeling and three-dimensional modeling - Google Patents

Description

The present invention relates to a resin powder for three-dimensional modeling, a three-dimensional model, and a method for producing the three-dimensional model.

In recent years, three-dimensional modeling technology, also called a 3D printer, has attracted a lot of attention. There are several types of three-dimensional modeling methods, and the characteristics of the materials and objects that can be used differ for each method. As one of several molding methods, a PBF (Powder Bed Fusion) method capable of high-strength and high-precision molding is known (for example, Patent Documents 1 to 4).

Currently, the resin mainly used in the PBF method resin is a polyamide resin. The polyamide resin is a crystalline thermoplastic resin. The crystalline resin is a resin that has a heat absorption peak in the differential scanning calorimetry (DSC) when the measurement of JISK7121 (plastic transition temperature measurement method: ISO3146) is performed, and indicates a state of melting and melting. The peak temperature of the heat absorption curve is called the melting point Tm. Further, since the polyamide resin powder has high absorbency of the laser beam, the polyamide resin powder easily reaches the melting point Tm or more by irradiation with the laser beam and is fluidized and fused, which is suitable for the PBF method.

In recent years, there has been an increase in demand for using a modeled object as a final product in addition to prototype applications, and there is an increasing demand for using various resins.
However, in order to use such a resin in a PBF method device, unlike ordinary powder, high fluidity and thermal stability against overheating are required, and there are cases where it cannot be used simply by crushing conventional resin pellets. many. In particular, fluidity is an important property for forming a smooth powder layer in the laminating process. If the fluidity is insufficient, the clogging of the powder may be uneven depending on the stacking position, and a powder layer containing many voids may be locally formed. These voids lead to the formation of pores in the modeled object when the model is formed by irradiating the laser, which deteriorates the mechanical properties of the modeled object. Further, if the smoothness of the laminated surface is low, the smoothness of the surface of the modeled object also decreases, and the dimensional accuracy of the modeled object decreases.

A method of coating the surface of the raw material powder with anti-aggregation particles having an average particle diameter of 1 μm or less has been proposed in order to improve the fluidity (for example, Patent Document 5). There is a problem that the particles reduce the strength of the modeled object.

As described above, there is a demand for a resin powder for three-dimensional modeling which has high dimensional stability, can form a high-density and high-quality modeled object, and is suitable for the PBF method.

The present invention has been made in view of the above problems, and provides a resin powder for three-dimensional modeling which has high dimensional stability, can form a high-density and high-quality modeled object, and is suitable for the PBF method. The purpose is.

In order to solve the above problems, the present invention is a three-dimensional modeling resin powder having resin particles, and the content of the resin particles having a particle size of 25 μm or less is 4% by weight or less with respect to the three-dimensional modeling resin powder. der is, and the content of the following of the resin particles with particle sizes of 32μm or less 2 wt% with respect to the stereolithographic resin powder, the number contained in the number particle size distribution of the resin particles following calculated particle size 2μm from The amount is 30% by number or less with respect to the resin powder for three-dimensional modeling, the volume average particle size (Dv) is 40 to 100 μm, and the specific surface area measured by the BET method is 0.06 to 0.51 m ² / g. It is characterized by being.

According to the present invention, it is possible to provide a resin powder for three-dimensional modeling which has high dimensional stability, can form a high-density and high-quality modeled object, and is suitable for the PBF method.

It is a figure for demonstrating an example of the manufacturing method of a three-dimensional model.

Hereinafter, a method for producing a resin powder for three-dimensional modeling, a three-dimensional model, and a three-dimensional model according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments shown below, and can be modified within the range conceivable by those skilled in the art, such as other embodiments, additions, modifications, and deletions. However, as long as the action and effect of the present invention are exhibited, it is included in the scope of the present invention.

The present invention is a three-dimensional modeling resin powder having resin particles, wherein the content of the resin particles having a particle size of 25 μm or less is 4% by weight or less with respect to the three-dimensional modeling resin powder. Since the resin powder for three-dimensional modeling of the present invention has a highly controlled particle size distribution, a laser sintering method based on the PBF (Powder Bed Fusion) method, for example, SLS (Selective Laser Sintering) It is particularly useful for forming three-dimensional shaped products that utilize the (sintering) method or the SMS (Selective Mask Sintering) method.

As a result of diligent studies, the present inventors have found that in order to obtain a high-quality model with high dimensional stability, it is related to the particle size of the resin powder for three-dimensional modeling, which is a material. By controlling the particle content with a particle size of 25 μm to 4% by weight or less, the surface smoothness during lamination can be maintained up to a high temperature range, the surface smoothness and density of the modeled object are improved, and high dimensional stability and high quality are achieved. You can get a good model.
Hereinafter, one embodiment of the present invention will be described.

(Resin powder for 3D modeling)
The resin powder for three-dimensional modeling of the present embodiment preferably contains a thermoplastic resin composition having resin particles and having crystallinity. The crystalline thermoplastic resin composition can be said to be a thermoplastic crystalline resin (also referred to as a crystalline thermoplastic resin or the like), and is melted when JISL7121 (plastic transition temperature measuring method: ISO3146) is measured. A peak is present.

The crystalline thermoplastic resin composition may be crystal-controlled, and the crystal-controlled crystalline thermoplastic resin is controlled in crystal size and crystal orientation by a method such as heat treatment, stretching, or external stimulation. It means that.

The method of crystal control can be changed as appropriate. For example, a method of heating the powder at a temperature equal to or higher than the glass transition point of each resin to perform an annealing treatment for increasing crystallinity, or applying ultrasonic waves. By doing so, a method of increasing crystallinity, a method of dissolving in a solvent and slowly volatilizing to increase crystallinity, a method of crystallinity growth by an external electric field application treatment, etc., and stretching to achieve high orientation and high crystallinity. Examples thereof include a method of pulverizing the obtained product by pulverization or the like to obtain a highly crystalline resin powder.

The degree of crystallization when crystallized in this way is also referred to as the degree of crystallization (crystallinity), but the degree of crystallization is generally reset by heating and melting at a melting point or higher. Therefore, when investigating how much the crystallinity has increased, heat it above the melting point, melt it sufficiently, cool it, and heat it again to obtain a crystallinity close to the state where crystallinity is not controlled. It can be measured and evaluated based on this.

From such a viewpoint, when the measurement of JISK7121 (plastic transition temperature measuring method: ISO3146) is carried out, it is preferable that the following is obtained in the differential scanning calorimetry (DSC). That is, in DSC measurement, the degree of crystallization (first degree of crystallization) obtained from the amount of energy of the heat absorption peak when the temperature is raised to + 30 ° C. (at the time of the first temperature rise), and then cooled to room temperature or lower. After that, when comparing the crystallinity (second crystallinity) required when the temperature is raised to the melting point + 30 ° C. (the second temperature rise), the second crystallinity is higher. High is preferable. Further, from the viewpoint of obtaining higher dimensional stability, it is preferable that the second crystallinity is higher.

In the PBF method, powder lamination is carried out while raising the temperature to near the melting point of the resin powder for three-dimensional modeling. Therefore, it is preferable to maintain the smoothness of the laminated surface in a wide temperature range. However, the resin particles having a particle size of 25 μm or less adhere to the rollers that smooth the surface during lamination, which causes dents and swelling on the laminated surface. Further, the adhesion of the resin particles to the rollers becomes more intense as the lamination temperature becomes higher because the powder surface becomes softer, and the frequency of occurrence increases.

On the other hand, as described above, in the three-dimensional modeling resin powder of the present embodiment, the content of the resin particles having a particle size of 25 μm or less is 4% by weight or less with respect to the three-dimensional modeling resin powder. By reducing the content of the resin particles having a particle size of 25 μm or less (4% by weight or less in this embodiment), it is possible to prevent the resin particles from adhering to the rollers or the like during the laminating process. It is possible to prevent the occurrence of shavings until the lamination temperature is close to the melting point of the resin powder for three-dimensional modeling. As a result, the smoothness of the laminated surface can be maintained in a wide temperature range.

According to the present embodiment, since the smoothness of the laminated surface is good, the smoothness of the surface of the obtained three-dimensional model is also improved, high dimensional stability is obtained, and a high-quality three-dimensional model can be obtained. Further, in the resin powder for three-dimensional modeling of the present embodiment, it is possible to suppress the occurrence of unevenness in the clogging of the powder, improve the density, and obtain a high-quality three-dimensional model.

The smoothness of the laminated surface can be evaluated by, for example, the recoatability. The recoatability is to evaluate the smoothness of the laminated surface of the powder material layer when the powder material layer is formed by laminating the resin powder for three-dimensional modeling. It can be said that the smoothness of the laminated surface is good when the recoating property is good.

As a method for measuring the particle size of the resin particles in the resin powder for three-dimensional modeling, Nikkiso Co., Ltd.'s Microtrack MT3300EXII is used, and the particle refractive index of each resin is used for the measurement.

In the present embodiment, the content of the resin particles having a particle size of 32 μm or less is preferably 2% by weight or less with respect to the resin powder for three-dimensional modeling. In this case, the generation of coarse particles during heating can be further prevented, and the smoothness of the laminated surface can be further maintained even when the lamination temperature becomes high.

Further, in the present embodiment, it is preferable that the number content of the resin particles having a particle size of 2 μm or less calculated from the number particle size distribution is 30% by number or less with respect to the resin powder for three-dimensional modeling. In this case, the generation of coarse particles during heating can be further prevented, and the smoothness of the laminated surface can be maintained at a higher level even when the lamination temperature becomes high.

The number particle size distribution of the three-dimensional modeling resin powder can be measured using, for example, Sysmex's flow-type particle image analyzer FPIA-3000S or the like.

Furthermore, it is preferable that the volume average particle diameter (Dv) of the resin powder for three-dimensional modeling of the present embodiment is 40 to 100 μm. In the PBF type apparatus, when the thickness of one layer at the time of stacking is about 100 μm, if a large number of particles larger than 100 μm are present, unevenness may occur on the laminated surface or blockage may occur. In order to improve the dimensional accuracy of the modeled object, it is preferable that the volume average particle size is small. However, if it is smaller than 40 μm, the bulk density of the powder composition becomes small, and the density of the modeled object tends to decrease.

The specific surface area measuring method of the resin powder for three-dimensional modeling is roughly classified into a permeation method and a gas adsorption method, and the gas adsorption method includes a capacitance method, a gravimetric method, and a flow method. Since the measurement is easy and the reproducibility is high, the BET method by low-temperature and low-humidity physical adsorption of an inert gas is preferable.

In the resin powder for three-dimensional modeling of the present embodiment, the specific surface area measured by the BET method ^{is preferably 0.06 to 5.8 m 2} / g. If it is larger than 5.8, the thermal meltability becomes high, and when melting by laser irradiation, the surrounding particles are also melted, and the dimensional stability may be lowered. Further, when it is smaller than 0.06, the thermal meltability becomes low, and the particles that are incompletely melted at the time of melting by laser irradiation are bound to each other, and coarse particles are likely to be generated.
Further, the resin powder for three-dimensional modeling of the present embodiment may have a pore structure.

As described above, in the PBF method, the powder laminating is carried out while raising the temperature to near the melting point of the resin powder for three-dimensional modeling. Therefore, it is preferable to maintain the smoothness of the laminated surface in a wide temperature range, but if cracks occur on the laminated surface during powder lamination, defects occur in the entire or part of the modeled object, resulting in poor modeling.

In order to prevent the occurrence of cracks, it is preferable to prevent the occurrence of heat shrinkage of the three-dimensional modeling resin powder and control the thermal meltability of the three-dimensional modeling resin powder. As in the present embodiment, the content of resin particles having a particle size of 25 μm or less, the content of resin particles having a particle size of 32 μm or less, and the resin particles having a particle size of 2 μm or less calculated from the number particle size distribution in the resin powder for three-dimensional modeling. When the number content, volume average particle size, and specific surface area value are controlled within suitable ranges, it is possible to prevent the three-dimensional modeling resin powder from melting to near the melting point of the three-dimensional modeling resin powder, and cracks occur on the laminated surface. It can be modeled well without any problems.

Examples of the crystalline thermoplastic resin composition in the present embodiment include polyolefins, polyamides, polyesters, polyether ketones, polyarylketones, polyphenylene sulfides, liquid crystal polymers (LCPs), polyacetals, polyimides, fluororesins and the like. .. These polymers or a combination of polymers can be used in an appropriate amount, and is composed of one or more types.

Examples of the polyolefin include PE (polyethylene) and PP (polypropylene).
Examples of the polyamide include PA410, PA6, PA66, PA610, PA612, PA11, PA12, semi-aromatic PA4T, PAMXD6, PA6T, PA9T, PA10T and the like. For example, PA9T is also called polynonamethylene terephthalamide, and is called semi-aromatic because carbon is composed of nine diamines and a terephthalic acid monomer, and the carboxylic acid side is generally aromatic. Further, the polyamide of the present embodiment also includes what is called aramid formed of p-phenylenediamine and a terephthalic acid monomer as a total aromatic whose diamine side is also aromatic.

Examples of polyester include PET (polyethylene terephthalate), PBT (polybutadiene terephthalate), PLA (polylactic acid) and the like. The present embodiment also includes an aromatic polyester containing a part of terephthalic acid or isophthalic acid in order to impart heat resistance.

Examples of polyethers include PEEK (polyetheretherketone), PEK (polyetherketone), PEKK (polyetherketone ketone), PAEK (polyetheretherketone), PEEKK (polyetheretherketone ketone), and PEKEKK (polyetherketone ketone). Etherketone ketone) and the like.

In addition, it may be a crystalline polymer, polyacetal, polyimide, polyether sulfone, or the like, or may have two melting point peaks such as PA9T. In order to completely melt the resin, it is preferable to raise the resin temperature above the second melting point peak.

In addition to the thermoplastic resin composition, the resin powder for three-dimensional modeling contains, for example, a filler made of an inorganic material or an organic material, a flame retardant agent or a plasticizer, a heat stability additive, a crystal nucleating agent, or the like. Additives, non-crystalline resins and the like can be contained, which may be blended with or absorbed on the polymer particles.

The resin powder for three-dimensional modeling of the present invention preferably contains a filler made of an inorganic material, and more preferably contains a filler. By including the filler, the heat resistance can be improved and the generation of coarse particles can be prevented.
Examples of the shape of the filler include, but are not limited to, fine particles of 10 μm or less, fibrous, needle-like, bead-like, and the like.

The filler is preferably contained in an amount of 0.1% by weight or more and 95% by weight or less based on the total weight of the resin powder for three-dimensional modeling. Further, it is more preferably contained in an amount of 5.0% by weight or more and 70% by weight or less, and further preferably contained in an amount of 10% by weight or more and 50% by weight or less.

Further, the filler is more preferably one or more selected from layered silicates (for example, talc), carbon, glass, metals and metal oxides. Examples of the metal include aluminum, magnesium, zirconium and the like.

In addition to the above, the resin powder for three-dimensional modeling of the present embodiment may contain a fluidizing agent. The amount of the fluidizing agent added may be a sufficient amount to cover the surface of the particles, and is preferably 0.1% by weight to 10% by weight with respect to the resin powder for three-dimensional modeling.

As the fluidizing agent, for example, a granular inorganic material having a volume average particle diameter of less than 10 μm is preferable.
Examples of the fluidizing agent include alumina, glass-like silica, titania, hydrated silica, those modified on the silica surface with a silane coupling agent, magnesium silicate and the like. Further, as a strengthening agent for improving strength, glass filler, glass beads, carbon fiber, aluminum balls and the like may be contained.

Further, the resin powder for three-dimensional modeling of the present embodiment is preferably appropriately dried, and may be dried before use by using a vacuum dryer or silica gel.

The resin powder for three-dimensional modeling of the present embodiment can be used as a material for laser sintering, and can be used for the SLS method, the SMS method, and the like. The three-dimensional modeling resin powder of the present embodiment has an appropriate balance of parameters such as appropriate particle size, particle size distribution, heat transfer characteristics, melt viscosity, bulk density, flow characteristics, melt temperature, and recrystallization temperature in these methods. It exhibits the characteristics showing. For example, in order to promote the degree of laser sintering in the PBF method, a large bulk density is preferable, and the bulk density is preferably 0.3 g / cc or more, more preferably 0.35 g / cc or more, and 0.4 g / cc or more. Is more preferable, but the resin powder for three-dimensional modeling of the present embodiment shows a good bulk density.

(Manufacturing method of resin powder for three-dimensional modeling)
The method for producing the resin powder for three-dimensional modeling of the present embodiment can be appropriately selected. For example, freeze pulverization in which a resin is frozen and pulverized can be mentioned. In addition to this, a method of stretching and cutting the resin into fibers by an extrusion processing machine (also referred to as a fiber cutting method) and a polymerization method can be mentioned.

The freeze crushing can be changed as appropriate, but resin powder can be obtained by crushing from the form of pellets or the like, and a crushing device is used at room temperature to filter particles other than the desired particle size. Perform classification operations. As the classification, for example, a mesh or the like having an appropriately selected mesh size is used to remove coarse powder and fine powder. Further, the particle size can be adjusted by appropriately adjusting the target pulverization particle size at the time of pulverization.

Further, the pulverization is preferably carried out at a low temperature of 0 ° C. or lower (a fragile temperature or lower of each resin itself), more preferably −25 ° C. or lower, and further preferably at an extremely low temperature of −100 ° C. or lower. Grinding is performed by utilizing the resin brittleness at low temperature.
The crushing device can be changed as appropriate, and examples thereof include a pinned mill, a counter jet mill, and a baffle plate impact crusher.
The treatment for controlling crystallization as described above may be performed before or after pulverization.

Further, it is preferable to perform a spheroidizing step after crushing to round the angular corners. Examples of the spheroidization include the use of a solvent that dissolves the resin, the spheroidization by a stirring device or the like while applying heat, and the like.

The fiber cutting method can be appropriately changed. For example, the fiber is adjusted to several tens of μm to several hundreds of μm by stretching several times from the form of pellets or the like, and then the fiber is adjusted to several μm to several hundreds of μm. Perform by laser cutting or cutting with a blade.

(Manufacturing method of three-dimensional model and three-dimensional model)
The method for producing a three-dimensional model of the present embodiment includes a step of forming a powder material layer made of the resin powder for three-dimensional modeling and a step of melting the powder material layer, and these steps are repeated to form a three-dimensional object. Form a model.

In the method for producing a three-dimensional model of the present embodiment, a powder material layer made of resin powder for three-dimensional modeling is formed, the powder material layer is melted to form a sintered layer, and a resin powder for three-dimensional modeling is further formed on the sintered layer. The process of forming a powder material layer composed of the same material is repeated. Then, the process is continued until a desired three-dimensional model is produced.

The step of forming the powder material layer can be appropriately changed, and examples thereof include a method of drawing a resin powder for three-dimensional modeling with a roller or the like to form a powder material layer.

The step of melting the powder material layer can be appropriately changed, and examples thereof include a method of electromagnetic irradiation, a method of using an inhibitor or an absorbent, and the like. Among them, electromagnetic irradiation is preferable, and it is more preferable to selectively perform electromagnetic irradiation.

The electromagnetic irradiation can be changed as appropriate, and examples thereof include a laser light source, an infrared irradiation source, a microwave generator, a radiant heater, an LED lamp, and the like, and these may be combined. When a laser light source is used, the laser may be selectively and directly irradiated, or the laser may be irradiated flatly using a mask. Above all, it is preferable to selectively irradiate the laser directly.

When a mask is used, the selective mask sintering (SMS) technique can be used to produce the three-dimensional model of the present embodiment. The SMS process is described, for example, in US Pat. No. 6,531,086. In the SMS process, a shielding mask is used to selectively block infrared radiation and a portion of the powder material layer is selectively irradiated.

When the SMS process is used to produce a three-dimensional model from the three-dimensional modeling resin powder of the present embodiment, one kind of substance that enhances the infrared absorption characteristics of the three-dimensional modeling resin powder is contained in the three-dimensional modeling resin powder. It is preferable to contain the above.
Examples of the substance that enhances the infrared absorption characteristics of the resin powder for three-dimensional modeling include a heat absorber and a dark-colored substance (carbon fiber, carbon black, carbon nanotube, carbon fiber, cellulose nanofiber, etc.).

As described above, the resin powder for three-dimensional modeling of the present embodiment is suitably used for producing a three-dimensional model by the PBF method. In this case, the three-dimensional model preferably includes a plurality of laminated and bonded sintered layers containing a polymer matrix.

As described above, the powder material layer is melted to form the sintered layer, and the thickness of the sintered layer can be appropriately changed by the molding process. Each of the plurality of sintered layers is preferably 10 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more per layer on average.

The three-dimensional model of the present embodiment is made of the resin powder for three-dimensional modeling of the present embodiment. The three-dimensional model is preferably smooth, and it is possible to form a surface exhibiting sufficient resolution that exhibits a minimum orange peel or less with respect to the three-dimensional model of the present embodiment.
The orange peel generally refers to the presence of an inappropriate rough surface on the surface of a three-dimensional model formed by laser sintering by the PBF method, or surface defects such as a pore problem and a distortion problem, for example, empty. The holes are not only aesthetically pleasing, but also have a significant effect on mechanical strength.
In addition, the three-dimensional model of the present embodiment is advantageous because it does not exhibit process characteristics such as warpage, distortion, and smoke generation due to the phase change that occurs between sintering and cooling after sintering.

The resin powder for three-dimensional modeling of the present embodiment is used for use in prototypes of electronic device parts, prototypes for strength tests, small-quantity products used in aerospace, dress-up tools of the automobile industry, and the like. Can form articles.
The PBF method, SLS method, and SMS method are expected to be superior in strength to the FDM (Fused Deposition Modeling) and inkjet methods, and therefore can be expected to withstand use as practical products. The production speed is considered to be slower than that of mass production methods such as injection molding, but the required production volume can be achieved by, for example, producing a large number of small parts in a plane. In addition, since a mold unlike injection molding is not required, overwhelming cost reduction and delivery time reduction can be achieved in trial production and prototype production.

FIG. 1 is a schematic view showing an example of an apparatus for carrying out the method for manufacturing a three-dimensional model of the present embodiment. As shown in FIG. 1, the powder is stored in the powder supply tank 5 and supplied to the laser scanning space 6 by using a roller 4 according to the amount used. The temperature of the supply tank 5 is preferably controlled by the heater 3. The laser output from the electromagnetic irradiation source 1 is irradiated to the laser scanning space 6 using the reflecting mirror 2. The heat from the laser can be used to sinter the powder to obtain a three-dimensional model.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples. In addition, Examples 1, 3, 4, 8 to 12 are Reference Examples 1, 3, 4, 8 to 12, which are not included in the present invention.

(Example 1)
PBT resin (manufactured by Polyplastics) was freeze-crushed with a target particle size of 65 μm to obtain PBT resin powder. The obtained PBT resin powder was removed with a 200 mesh (opening 75 μm) to obtain a resin powder for three-dimensional modeling. The freezing and crushing was carried out by Osaka Gas Liquid Co., Ltd. (Sakai City, Osaka Prefecture), and the freezing and crushing conditions were set to a crushing outlet temperature: -100 to -120 ° C. and a crushing device peripheral speed: 80.0 m / s.
The obtained resin powder for three-dimensional modeling was measured as follows, and a resin having a particle size of 2 μm or less calculated from the content of resin particles having a particle size of 25 μm or less, the content of resin particles having a particle size of 32 μm or less, and the number particle size distribution. The number content of particles, volume average particle size (Dv), and specific surface area were determined. The results are shown in Table 1.

(Example 2)
Fine powder was removed from the resin powder for three-dimensional modeling obtained in Example 1 with a 400 mesh (opening 34 μm) to obtain a resin powder for three-dimensional modeling.

(Example 3)
In Example 1, the same treatment as in Example 1 was carried out except that the target particle size for crushing was changed to 70 μm, to obtain a resin powder for three-dimensional modeling.

(Example 4)
In Example 1, the target particle size for crushing was set to 100 μm, and the same treatment as in Example 1 was carried out except that the coarse powder was not removed with 200 mesh to obtain a resin powder for three-dimensional modeling.

(Example 5)
In Example 4, the same treatment as in Example 4 was carried out except that the PBT resin was changed to PA12 resin (manufactured by Daicel Evonik) to obtain a resin powder for three-dimensional modeling.

(Example 6)
In Example 4, the same treatment as in Example 4 was carried out except that the PBT resin was changed to PA66 resin (manufactured by Asahi Kasei) to obtain a resin powder for three-dimensional modeling.

(Example 7)
After stirring PBT resin (made by Polyplastics) at a temperature 30 ° C higher than the melting point using an extrusion processing machine (manufactured by Japan Steel Works, Ltd.), use a resin with a circular nozzle opening to form a fibrous three-dimensional molding resin. The lysate was stretched. The number of threads coming out of the nozzle was 100. After stretching about 4 times to make a fiber with a fiber diameter of 55 μm and an accuracy of ± 4 μm, it is cut with a push-cut type cutting device (manufactured by Ogino Seiki Seisakusho, NJ series 1200 type) at 0.06 mm (60 μm). , A resin powder for three-dimensional modeling was obtained.

(Example 8)
A commercially available powder of PA12 resin (daicel evonik polymerization method powder) was purchased to obtain a resin powder for three-dimensional modeling.

(Example 9)
In Example 1, the same treatment as in Example 1 was carried out except that the PBT resin was changed to a PP resin containing 30% talc (manufactured by Idemitsu Lion Composite) to obtain a resin powder for three-dimensional modeling.

(Example 10)
A commercially available powder of PA12 resin (PA2200 manufactured by EOS) was purchased to obtain a resin powder for three-dimensional modeling.

(Example 11)
After stirring PBT resin (made by Polyplastics) at a temperature 30 ° C higher than the melting point using an extrusion processing machine (manufactured by Japan Steel Works, Ltd.), use a resin with a circular nozzle opening to form a fibrous three-dimensional molding resin. The lysate was stretched. The number of threads coming out of the nozzle was 100. After stretching about 4 times to make a fiber with a fiber diameter of 90 μm and an accuracy of ± 4 μm, it is cut with a push-cut type cutting device (manufactured by Ogino Seiki Seisakusho, NJ series 1200 type) at 0.09 mm (90 μm). , A resin powder for three-dimensional modeling was obtained.

(Example 12)
The resin powder for three-dimensional modeling of Example 8 was sieved with a metal net of 330 mesh (opening 45 μm), and the resin powder for three-dimensional modeling was obtained from under the sieve.

(Comparative Example 1)
In Example 1, the same treatment as in Example 1 was carried out except that the target particle size for crushing was changed to 60 μm, to obtain a resin powder for three-dimensional modeling.

(Comparative Example 2)
In Example 1, the same treatment as in Example 1 was carried out except that the target particle size for crushing was changed to 50 μm, to obtain a resin powder for three-dimensional modeling.

(Comparative Example 3)
In Example 1, the same treatment as in Example 1 was carried out except that the target particle size for crushing was changed to 40 μm, to obtain a resin powder for three-dimensional modeling.

(Comparative Example 4)
In Example 9, the same treatment as in Example 9 was carried out except that the target particle size for crushing was changed to 50 μm, to obtain a resin powder for three-dimensional modeling.

(Measurement and evaluation)
<Particle measurement>
The measurement was performed using the Microtrack MT3300EXII manufactured by Nikkiso Co., Ltd., and the particle refractive index of each resin was used. For example, in PBT, the value of the refractive index was set to 1.57. The measurement was carried out by the dry (air) method without using a solvent at the time of measurement.

<Measurement of number particle size distribution>
The number particle size distribution was measured using a flow type particle image analyzer FPIA-3000S manufactured by Sysmex Corporation. The measurement solution was dispersed by sonication for 5 minutes. Further, a particle shape image was acquired in a state where the measurement range was set to 0.5 to 200 μm and the number of powder particle counts was 3,000 or more, and the number particle size distribution was obtained. The cumulative content with a particle size of 0.5 to 3.0 μm was defined as the number content with a particle size of 2 μm or less.

<BET method specific surface area measurement>
The specific surface area was measured using the automatic specific surface area measuring device Gemini VII2390 manufactured by Shimadzu Corporation. The pretreatment was carried out under vacuum at 80 ° C. for 5 hours or more. The sample filling amount was set so that the total specific surface area value of the sample was 0.01 m ² / g or more, and the measurement temperature was the liquid nitrogen temperature. The measurement was carried out twice using krypton as the measurement gas, the specific surface area was calculated by the multipoint method, and the average value was used as the measured value.

<Recoating property>
An AMS5500P manufactured by Ricoh Co., Ltd. (see FIG. 1), which is an SLS manufacturing apparatus, was used to evaluate the recoatability in the laminating process. As shown in FIG. 1, the temperature of the supply tank 5 is raised, the resin powder for three-dimensional modeling obtained above is supplied to the laser scanning space 6 by the roller 4, and the laminated surface when the powder material layer is formed is formed. The smoothness was evaluated. The recoatability was evaluated under the temperature conditions of room temperature, room temperature to 100 ° C., 100 ° C. to 200 ° C., 100 ° C. to (melting point −15) ° C., and 200 ° C. to (melting point −15) ° C. The melting point represents the melting point of each resin powder for three-dimensional modeling.
The pretreatment of the resin powder was carried out under vacuum at 45 ° C. under reduced pressure for 8 hours. The stacking setting conditions were a stacking thickness of 0.1 mm and a recoating speed of 10 cm / s.

◎: The laminated surface is uniform ○: Small dents are generated on the laminated surface △: Small dents and dents are generated on the laminated surface ×: Cracks, lumps, and large dents are generated on the laminated surface

Further, the three-dimensional model produced using the three-dimensional modeling resin powder obtained in the examples had good surface smoothness and high quality, but was produced using the three-dimensional modeling resin powder obtained in the comparative example. The surface smoothness of the three-dimensional model was poor.

Tables 1 and 2 show the resin type, granulation method, measurement result and evaluation result of the resin powder for three-dimensional modeling.
In the evaluation of recoatability in Table 2, when the melting point of the resin powder for three-dimensional modeling exceeds 200 ° C., the evaluation of "100 ° C. to (melting point -15) ° C." is included in the evaluation of "100 ° C. to 200 ° C." Therefore, the column of "100 ° C. to (melting point -15) ° C." is set to "-".
Further, when the melting point is 100 ° C. to 200 ° C., "100 ° C. to 200 ° C." and "200 ° C. to (melting point -15) ° C." generate temperatures exceeding the melting point. The column of "200 ° C." and the column of "200 ° C. to (melting point -15) ° C." are designated as "-".

1 Electromagnetic irradiation source 2 Reflector 3 Heater 4 Roller 5 Supply tank 6 Laser scanning space

U.S. Pat. No. 4,247,508 U.S. Pat. No. 4,863,538 U.S. Pat. No. 5,017,753 U.S. Pat. No. 6,110,411 Japanese Patent No. 4846425

Claims (7)

A resin powder for three-dimensional modeling having resin particles.
Der 4 wt% or less content of the particle size 25μm or less of the resin particles relative to the stereolithographic resin powder is,
The content of the resin particles having a particle size of 32 μm or less is 2% by weight or less with respect to the resin powder for three-dimensional modeling.
The number content of the resin particles having a particle size of 2 μm or less calculated from the number particle size distribution is 30% by number or less with respect to the resin powder for three-dimensional modeling.
The volume average particle size (Dv) is 40 to 100 μm.
A resin powder for three-dimensional modeling, characterized in that the specific surface area measured by the BET method is 0.06 to 0.51 m ² / g. The resin powder for three-dimensional modeling according to claim 1 , wherein the resin particles contain a thermoplastic resin composition having crystallization. The crystalline thermoplastic resin composition is at least one selected from polyolefin, polyamide, polyester, polyether ketone, polyarylketone, polyphenylene sulfide, liquid crystal polymer (LCP), polyacetal, polyimide and fluororesin. 2. The resin powder for three-dimensional modeling according to claim 2. The resin powder for three-dimensional modeling according to claim 1, wherein the resin particles are PBT (polybutadiene terephthalate) or PP (polypropylene). The invention according to any one of claims 1 to 4 , wherein the filler is made of an inorganic material, and the content of the filler is 0.1 to 95% by weight based on the resin powder for three-dimensional modeling. Resin powder for 3D modeling. The resin powder for three-dimensional modeling according to claim 5 , wherein the filler is one or more selected from layered silicate, carbon, glass, metal and metal oxide. A three-dimensional modeled product comprises a step of forming a powder material layer made of the resin powder for three-dimensional modeling according to any one of claims 1 to 6 and a step of melting the powder material layer, and repeating these steps. A method for manufacturing a three-dimensional model, which is characterized by forming a three-dimensional object.

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