JP6839423B2 - Stereolithography slurry and method for manufacturing stereolithography using it - Google Patents

Description

The present invention relates to a slurry used in a stereolithography technique for producing a three-dimensional model and a method for producing a stereolithography using the slurry.

Stereolithography technology is known as a technology for manufacturing a three-dimensional modeled object.
The stereolithography technique is a technique for manufacturing a three-dimensional model by repeating a process of irradiating a photocurable resin with light to cure it. Further, a slurry in which inorganic particles of ceramic or metal are mixed with a photocurable resin is irradiated with light to be cured, the resin component is removed from the obtained photocurable product, and the inorganic component is sintered to obtain an inorganic component. A method of obtaining a three-dimensional model having the skeleton of is also known. For example, using the stereolithography apparatus shown in Patent Document 1, a thin layer of slurry was applied on a modeling table, an ultraviolet laser was scanned, and the process of curing the slurry into a predetermined pattern shape was repeated to cure the slurry three-dimensionally. A stereolithographic product is formed, and after removing the uncured slurry, a three-dimensional model is produced by degreasing and sintering to remove the resin component.
The slurry used in the stereolithography technique needs to have good fluidity when the uniform layer is applied by the recoater, and thixotropy to maintain the shape after the application is completed.

Further, in order to produce a model having a precise and fine structure, it is necessary to reduce the thickness of the slurry layer to be applied at one time, but if the particle size of the inorganic particles contained in the slurry is larger than 10 [μm]. , The smoothness of the surface of the slurry layer is lowered, and high-definition modeling becomes difficult. Therefore, a slurry in which inorganic particles having a fine particle size of 10 [μm] or less are mixed is required. (For example, Patent Documents 2 and 3)

JP-A-2018-20521 Japanese Unexamined Patent Publication No. 2001-26609 JP-A-2007-237683

When the particle size of the inorganic particles contained in the slurry is reduced in order to produce a high-definition model, it becomes difficult to uniformly mix the inorganic particles in the resin due to the aggregation of the inorganic particles. In order to avoid this, if the content of the inorganic particles is lowered, there is a problem that when the cured photocured product is sintered, it shrinks and problems such as cracks occur, and the yield of the stereolithographic product is lowered.
Further, the slurry needs to have a thixotropy property of having a low viscosity at the time of coating and a high viscosity after coating, but if the particle size of the inorganic particles to be contained is increased, sufficient thixotropy property can be realized. It will be difficult.

In view of the above problems, the present invention provides a stereolithography slurry containing inorganic particles having a fine particle size and capable of achieving sufficient thixotropy, and a method for producing a stereolithography product using the slurry. Is the subject.

The stereolithography slurry according to the present invention
It contains a first inorganic particle, a second inorganic particle, and a photocurable resin.
The average particle size of the first inorganic particles is 1 to 5 [μm].
The average particle size of the second inorganic particles is 0.22 times or less the average particle size of the first inorganic particles.
The volume ratio of the second inorganic particles to the first inorganic particles is 0.01 or more.
The viscosity at a shear rate of 10 [1 / s] is 50 [Pa · s] or less.
The viscosity at a shear rate of 0.01 [1 / s] is 500 [Pa · s] or more.
It is characterized by that.

By using such a slurry for stereolithography, it is possible to obtain a slurry for producing a high-definition stereolithography product having good thixotropy.

By using a slurry having such characteristics, the slurry can be uniformly applied and the slurries can be laminated, which facilitates the production of a stereolithographic object having a high-definition three-dimensional structure.

Moreover, the slurry for stereolithography according to the present invention is
The first inorganic particles are characterized in that the volume ratio is equal to or greater than the solidification limit value.

Moreover, the slurry for stereolithography according to the present invention is
The total volume ratio of the first inorganic particles and the second inorganic particles is 65 to 70 [vol%].

Moreover, the slurry for stereolithography according to the present invention is
The volume ratio of the second inorganic particles to the first inorganic particles is 0.10 to 0.15.

By using such a stereolithography slurry, it is possible to reduce shrinkage when sintering a photocured product formed from the stereolithography slurry, and to produce a high-definition stereolithography product with high accuracy. It becomes.

The method for manufacturing a stereolithographic object according to the present invention is
The first step of discharging the above-mentioned stereolithography slurry and
The second step of stretching the stereolithography slurry to form a slurry layer having a thickness of 5 to 200 [μm], and
A third step of scanning the slurry layer into a predetermined pattern shape and irradiating the slurry layer with laser light.
A step of forming a photocured product from the slurry layer by repeating the first, second and third steps, and
The first heat treatment step of heat-treating the photocurable product to remove the photocurable resin, and
It is characterized by including a second heat treatment step of heat-treating and sintering the photocured product after the first heat treatment step.

The method for manufacturing a stereolithographic object according to the present invention is
In the first step or the first step and the second step, the temperature of the stereolithography slurry is maintained at 35 to 60 [° C.].

By such a method for manufacturing a stereolithographic object, a high-definition stereolithographic object can be easily produced with good reproducibility.

According to the present invention, it is possible to provide a stereolithography slurry capable of containing inorganic particles having a fine particle size at a high density and realizing sufficient thixotropy, and a stereolithography method using the slurry.

The conceptual diagram which shows the main part of a stereolithography apparatus. The figure which shows the close-packed state by two kinds of particles. Viscosity shear rate dependence.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, none of the following embodiments give a limiting interpretation in finding the gist of the present invention. Further, the same or the same type of members may be designated by the same reference numerals and the description thereof may be omitted.

The particle size of the inorganic particles follows a lognormal distribution, and the "average particle size" of the inorganic particles means the particle size at an integrated value of 50% in the particle size distribution of the particle size. The particle size (particle size) was measured by using a wet laser diffraction / scattering method (Microtrac MT330) and SEM observation measurement.

(Embodiment 1)
Hereinafter, a slurry containing inorganic particles in a photocurable resin used in a stereolithography technique will be described.

<Manufacturing process of stereolithography>
FIG. 1 is a conceptual diagram showing a main part of the stereolithography apparatus disclosed in Patent Document 1.
As shown in FIG. 1A, the stereolithography slurry 1 is discharged from the dispenser 2 and deposited on the upper surface of the auxiliary table 3.
After that, as shown in FIG. 1 (b), the recorder 4 moves above the modeling table 5 in the Y direction in the drawing, for example, at a speed of 1 to 5 [mm / s], and is deposited on the upper surface of the auxiliary table 3. The slurry 1 is stretched on the modeling surface 5a of the modeling table 5 to form a slurry layer 1a having a uniform thickness. The moving speed of the recorder 4 is appropriately adjusted according to the viscosity characteristics of the slurry 1 and the coating thickness.
For example, if the speed of the recorder 4 is set to be 20 to 200 [1 / s] as a typical shearing speed with respect to the thickness of the slurry layer 1a of 50 [μm], the above speeds 1 to 1 It becomes 5 [mm / s]. The speed of the recorder 4 depends on the characteristics of the slurry 1, especially the thixotropy property described later.
The thickness of the slurry layer 1a is 5 to 200 [μm], and the thickness of the slurry layer 1a suitable for producing a high-definition stereolithography is 5 to 50 [μm].
The thickness of the slurry layer 1a can be adjusted by adjusting the height of the recoater 4 in the Z direction.
That is, due to the interval formed in the Z direction between the XY plane formed by the upper surface (surface) of the modeling surface 5a (or the slurry layer 1a formed immediately before) and the XY plane through which the lower end of the recoater 4 passes. The thickness of the slurry layer 1a formed by the movement of the recorder 4 is determined.

After that, the formed slurry layer 1a is scanned and exposed to laser light having a photosensitive wavelength of the photocurable resin contained in the slurry 1.
The optical path of the laser beam is controlled by an optical system using a lens or a mirror (not shown), and the laser beam is scanned in a predetermined pattern on the XY plane.
At the portion irradiated with the laser light, the photocurable resin contained in the slurry 1 is cured by a photochemical reaction. As a result, in the slurry 1 in the slurry layer 1a, the portion of the predetermined pattern that has been scanned and exposed is cured, and the cured layer 6 is formed. The portion not irradiated with the laser beam remains as the uncured slurry 1.

After that, the modeling table 5 moves (descends) in the Z direction at a distance corresponding to the thickness of the slurry layer 1a, for example, 5 to 200 [μm]. As a result, the upper surface of the cured layer 6 has the same height as the auxiliary table 3, and is in the state shown in FIG. 1 (a).
Here, a first step of discharging the stereolithography slurry 1 from the dispenser 2 and a second step of stretching the stereolithography slurry 1 by the recoater 4 to form a new slurry layer 1a on the cured layer 6. The third step of irradiating the slurry layer 1a with laser light in a predetermined pattern shape is repeated.

The above steps are repeated a predetermined number of times, and the cured layers 6 are laminated in the Z direction. The laminated cured layer 6 forms a photocured product cured into a predetermined three-dimensional shape.

The slurry 1 is used in the discharging step and the stretching step as described above, and since the slurry layer is laminated by repeating the discharging step and the stretching step, it is preferable to have thixotropic property. Thixotropy means that it has a high viscosity in a stationary state, and the viscosity decreases as the shear rate increases. Having a low viscosity while the shear rate is high makes it possible to discharge and stretch the slurry 1. Having a high viscosity in a stationary state makes it possible to maintain the shape of the laminated slurry layers. Having a low viscosity in a high shear rate is preferably 50 [Pa · s] or less at a shear rate of 10 [1 / s]. Here, the shear rate 10 [1 / s] is a value in consideration of the moving speed of the recorder 4. Having a high viscosity in a stationary state is preferably 500 [Pa · s] or more at a shear rate of 0.01 [1 / s].

Using the above-mentioned slurry having thixotropy, for example, by stretching the slurry with a recoater 4 at a shear rate of 10 [1 / s] or more, the layers of the slurry can be sequentially laminated uniformly and with good reproducibility. Here, as the number of layers increases, the gravity applied to the laminated uncured slurry increases, so that the slurry is required to have a high viscosity in order to maintain the shape after coating in the laminated state. By using a slurry having a shear rate of 0.01 [1 / s] and 500 [Pa · s] or more, the shape of the laminated slurry layers can be maintained, and as a result, a highly accurate three-dimensional model can be obtained. be able to.

In addition, in order to reduce the viscosity at the time of coating, the temperature of the dispenser 2, the recoater 4 and the auxiliary table 3 may be controlled, and the temperature of the slurry 1 may be maintained at 35 ° C to 60 ° C. In particular, due to thixotropy, when the viscosity at rest is very high, it may be difficult to discharge from the dispenser 2.
In that case, by keeping the temperatures of the dispenser 2 and the recoater 4 at least in the range of 35 to 60 ° C., the viscosity of the slurry 1 can be reduced and the slurry 1 can be discharged smoothly.
However, if the holding temperature exceeds 60 ° C., the photocurable resin may thermally react and the photocuring performance may deteriorate. Therefore, it is preferable that the holding temperature does not exceed 60 ° C.

Then, the uncured slurry 1 is dissolved and removed with an organic solvent or the like, and the region cured into a predetermined three-dimensional shape remains as a photocured product.

After that, the photo-cured product cured into a three-dimensional pattern shape is gradually heated to, for example, 500 to 600 ° C. in an air atmosphere (oxygen-containing atmosphere) and heat-treated to obtain a resin component contained in the photo-cured product. Is degreased by decomposing and vaporizing.
After that, the temperature is further raised, and when ceramic particles are used as the inorganic material, for example, the inorganic particles contained in the photocured product are sintered by heat treatment at 1500-1600 ° C., and then the temperature is lowered to room temperature.
The degreasing step and the sintering step may be continuously performed, but may be performed as separate steps.

Through the above steps, it is possible to provide a high-definition three-dimensional stereolithography made of an inorganic material sintered body.

<Slurry>
The requirements for the slurry to obtain a high-definition stereolithography are (1) having thixotropy from the process requirements for forming a photocured body, and (2) shrinkage in the sintering process. There are two points that is reduced. In this invention, a slurry that simultaneously satisfies the above requirements is provided by using a photocurable resin and inorganic particles as main constituents and setting the particle size and content of the inorganic particles within a specific range.

<Diameter of inorganic particles>
The slurry according to the present invention contains two kinds of inorganic particles having different average particle diameters and a liquid photocurable resin. Among the inorganic particles having different average particle diameters, the one having the larger particle size is referred to as the first inorganic particle, and the smaller one is referred to as the second inorganic particle.

A preferable range of the average particle size of the first inorganic particles is 1 to 5 μm. If the average particle size of the first inorganic particles exceeds 5 μm, the inorganic particles become too large with respect to the thickness of the slurry layer, and the slurry layer may not be uniformly formed in the stretching step, and the slurry layer formed may not be uniformly formed. Insufficient smoothness. If it is less than 1 μm, the cohesive force of the inorganic particles becomes strong, the viscosity of the slurry becomes high, and the fluidity required in the process cannot be secured.

The second inorganic particle is characterized in that it is sufficiently small as compared with the first inorganic particle. “Sufficiently small” means that there is a difference in the gap filled with the first inorganic particles to the extent that the second inorganic particles can enter. By mixing two kinds of particles having sufficiently different sizes in this way, the space in the slurry that would have been occupied by the photocurable resin without the second inorganic particles is replaced by the second inorganic particles. Be done. As a result, the ratio of the volume occupied by the inorganic particles in the slurry per unit volume, that is, the content rate of the inorganic particles can be increased as compared with the case where the first inorganic particles are blended alone. A high content of inorganic particles is effective in suppressing shrinkage in the sintering process.

Further, the thixotropic property is exhibited by the presence of the second inorganic particles in the gaps between the first inorganic particles and the relationship between them within a specific range. The reason for showing thixotropic property is not always clear, but it is considered that it depends on the geometrical arrangement of particles for the following reasons.

In a system in which a dispersion medium made of an organic resin is highly filled with micron-order inorganic particles, the inorganic particles repel each other by repulsive force, and move to a position where the repulsive force with surrounding particles moves and stops. It is considered to have a structure close to the close-packed structure. At this time, since the particles affect each other by the repulsive force and restrain them, this is observed as a highly viscous state from the macro viewpoint. When an external force is applied, the network structure formed by the particles restraining each other breaks, and the viscosity begins to decrease. The strength of the network structure depends on the geometry of the particles. In addition, the relationship between the shearing force corresponding to the target phenomenon and the force required to solve the network structure is also related to whether thixotropic property can be obtained in the phenomenon.

The preferred range of the average particle size of the second inorganic particles is 0.22 times or less the average particle size of the first inorganic particles. When the particle size of the first inorganic particles is 1 to 5 μm, the particle size of the second inorganic particles is preferably 1.1 μm or less. If it exceeds 1.1 μm, it becomes too large with respect to the first inorganic particles, and the effect of increasing the content of the inorganic particles and at the same time exhibiting thixotropy cannot be expected. If the particle size of the second particles is less than 0.05 μm, the second inorganic particles are likely to aggregate, and aggregated agglomerates are generated, making it difficult to crush the agglomerates. When 0.05 μm as the lower limit value is converted into a magnification with respect to the particle size of 1 to 5 μm, it becomes 0.05 times or less.

The volume ratio of the second inorganic particles to the first inorganic particles is 0.01 or more. If it is less than 0.01, the effect of replacing the gap between the first inorganic particles is too small. More preferably, it is 0.1 to 0.15. In the calculation of the volume ratio, when the volume of the particles cannot be measured directly, the value of the volume calculated from the weight and the density is used. When the same kind of material is used as the first inorganic particle and the second inorganic particle, the volume ratio is equal to the weight ratio.

FIG. 2 shows a close-packed state with two types of particles. First, assume a situation in which two types of inorganic particles having different particle sizes are arranged in the absence of resin. Ideally, the arrangement of the first inorganic particles in the hexagonal close-packed structure of the spherical particles is assumed, and the second inorganic particles having a small particle size are arranged inscribed between the first inorganic particles. A dense structure can be realized with.
FIG. 2 shows a state of closest packing by two different particles, the dotted line corresponds to the first inorganic particle, and the solid line corresponds to the second inorganic particle.
The average particle size of the second inorganic particles in the tightly packed state is 0.22 times the average particle size of the first inorganic particles according to geometrical considerations. At this time, the volume ratio of the first inorganic particles: the volume ratio of the second inorganic particles is 1: 0.01.
<Each component of slurry>
As the inorganic particles, metal particles and ceramic particles can be used. As the ceramic material, for example, alumina can be used, but silica, zirconia and the like can also be used.

The photocurable resin is not particularly limited, but for example, an acrylic resin having good stereolithography accuracy can be preferably used.
Since a fine pattern is formed by the laser light, a resin having a depth of penetration of the laser light of, for example, 5 to 200 [μm] can be preferably used.
Further, a surfactant may be contained in order to adjust the wettability with the inorganic particles.

<Verification of slurry composition and viscosity characteristics>
Slurries were prepared by changing the particle size and volume ratio of the inorganic particles, and the viscosity characteristics of the obtained slurry were verified. Alumina particles with an average particle size of 1.6 [μm] as the first inorganic particles, alumina particles with an average particle size of 0.18 [μm] as the second inorganic particles, and the composition shown below as a liquid photocurable resin. I used the one.
・ Methoxypropylene glycol acrylate 11.1g
-Tris (2-hydroxyethyl) isocyanurate triacrylate 4.1 g
・ 1-Hydroxycyclohexylphenyl ketone 0.8g
・ Allyl ether copolymer (dispersant) 1.0 g manufactured by NOF CORPORATION
In the mixing of these inorganic particles and the photocurable resin, the object to be mixed is housed in a container, and the container is subjected to revolution and rotation motion to perform stirring and defoaming treatment. It was performed using the device.
In order to evaluate the thixotropy characteristics of the produced slurry, the shear rate dependence of the viscosity was measured at a set temperature of 23 ° C. using a rheometer model MCR302ST manufactured by Anton Pearl Japan Co., Ltd. and a parallel plate 25 mmφ.

Samples of various slurries were prepared by changing the volume ratios of the first inorganic particles, the second inorganic particles, and the photocurable resin. Table 1 summarizes the conditions for each sample.
Table 1 shows the determination results of thixotropy for each sample of the slurry. Judgment criteria are 50 [Pa · s] or less at a shear rate of 10 [1 / s], 500 [Pa · s] or more at a shear rate of 0.01 [1 / s] is OK, and the others are NG. did. In addition, even when the viscosity could not be measured (for example, when it was solidified), it was determined to be NG.
In Table 1, a slurry containing one kind of average particle size inorganic particles is described as a comparative example.
In addition, FIG. 3 shows a comparison of the shear rate dependence of the viscosities of Samples 1, 4-10, and 12-13.

Table 1

First, as a comparison target, the characteristics of the slurry using one kind of average particle size inorganic particles will be described, and then the characteristics of the slurry using two kinds of average particle size inorganic particles will be described.
Sample 1 (Comparative Example 1)
As the inorganic particles, only the first inorganic particles were added to the photocurable resin in an amount of 60 [vol%], and the particles were stirred and defoamed by a rotating stirrer and mixed.
Sample 1 has thixotropy and satisfies the criterion at a high shear rate, but does not satisfy the criterion at a low shear rate as shown by x in FIG. 3, and is uncured as the number of layers increases. It is difficult to maintain the height of the slurry layer, and there is a risk of distortion of the modeling shape due to height displacement when drawing on the slurry layer, and it is difficult to use it as a high-definition optical modeling slurry.

Sample 2 (Comparative Example 2)
As the inorganic particles, only the first inorganic particles were added to the photocurable resin in an amount of 65 [vol%], and the mixture was stirred and defoamed by a rotating stirrer and mixed to prepare a slurry of Sample 2.
The first inorganic particles can be mixed with the photocurable resin without agglutination, but the mixed sample 2 solidifies and the viscosity cannot be measured. Therefore, when the first inorganic particles are added to the photocurable resin alone, the limit value at which the slurry solidifies (the minimum volume ratio at which the slurry solidifies, hereinafter referred to as "solidification limit value") is 60 to It can be understood that it exists in the range of 65 [vol%].
That is, although it is possible to secure the shape of the slurry of the sample 2 in a stationary state, it is not possible to apply a uniform slurry layer by the recorder 4 of the stereolithography apparatus, and the slurry is used as a stereolithography slurry. Is difficult to use.

From the results of Sample 1 and Sample 2, it is possible to adjust the viscosity by changing the content (volume ratio) of the inorganic particles in the composition of only the first inorganic particles, but if the content is high, it is applied by solidification. It can be understood that if the content is low, it is difficult to maintain the shape in a stationary state, and it is difficult to supply a slurry having thixotropy suitable for stereolithography with good reproducibility.

Sample 3 (Comparative Example 3)
As the inorganic particles, only the second inorganic particles were added to the photocurable resin in an amount of 60 [vol%], and the particles were stirred and defoamed by a rotating stirrer and mixed to prepare Sample 3. However, the second inorganic particles aggregated and could not be uniformly mixed with the photocurable resin, making it impossible to measure the viscosity.
When 65 [vol%] of the second inorganic particles were added to the photocurable resin, the second inorganic particles also aggregated and could not be uniformly mixed with the photocurable resin.
From the comparison with Samples 1, 2 and 3, it is understood that even if the content of the inorganic particles is the same volume ratio, it becomes difficult to mix with the resin due to the finer particle size of the inorganic particles. it can.

Samples 4 to 13 (Examples and Comparative Examples)
Samples 4 to 13 are slurries in which the volume ratios of the first inorganic particles and the second inorganic particles are changed in the photocurable resin, and the slurry is agitated and defoamed by a public rotation agitator and mixed.
In Table 1, the samples 7 to 10 and 13 in which the volume ratio of the second inorganic particles to the first inorganic particles is 0.1 or more and 0.15 or less satisfy the criteria for thixotropy and are suitable for the stereolithography slurry. It can be understood that it is a sample. The sample 11 was solidified in a stationary state after mixing, and the viscosity could not be measured. Therefore, the judgment was NG.
In FIG. 3, samples 4 (■), 5 (□), 6 (▲), 7 (●), 8 (◇), 9 (○), 10 (◆), 12 (+), and 13 (△) are shown. Shows the shear rate dependence of viscosity. Samples 4-6 and 12 have a high viscosity value at a shear rate of 10 [1 / s]. Therefore, when the slurry is stretched using a recoater or the like to form a slurry layer, the coating film is cut off. , And it is not possible to stably create a continuous slurry layer.

Comparing samples with the same volume ratio of around 65 [vol%], if the inorganic particles contained are only the first inorganic particles, the slurry will solidify (Sample 2). If only the second inorganic particles are used, the slurry itself cannot be prepared because the particle size is likely to cause agglutination (Sample 3). However, when the first inorganic particles and the second inorganic particles are used in combination, a slurry showing viscosity in both the low speed region (<1 [1 / s]) and the high speed region (> 1 [1 / s]) can be obtained. (Sample 4). However, in order to produce a high-definition stereolithography using this slurry, the viscosity in the high-speed range is still too high at this stage, which is not suitable. By increasing the proportion of the second particles, there is a region where a slurry that achieves good thixotropy can be obtained (Samples 7-10, 13). At this time, the volume ratio of the first particles is, that is, a sample containing the inorganic particles at a volume ratio (greater than or equal to the solidification limit value) at which the slurry solidifies when the first inorganic particles are added alone. However, by using the first inorganic particles and the second inorganic particles in combination, it is possible to obtain a slurry having good thixotropic properties (the determination is OK).
Samples 7 to 10 and 13 contain inorganic particles in a content higher than that in Samples 1 and 2 containing only the first inorganic particles. Therefore, if a stereolithographic product is produced using these samples, a photocured product can be obtained. Since the density of the inorganic particles inside is high, that is, the amount of resin components removed during the removal and sintering steps is small, shrinkage during sintering can be reduced.

From the above results, it is preferable that the total volume ratio of the first inorganic particles and the second inorganic particles is 65 to 70 [vol%]. Further, according to the combination of inorganic particles in the present invention, it is possible to provide a slurry having good thixotropy even at the above volume ratio and suitable for producing a stereolithographic product.

Further, the particle size of the second inorganic particles is 0.22 times or less, preferably 0.11 times (average particle size 0.18 [) with respect to the particle size of the first inorganic particles (average particle size 1.6 μm). μm]), and by setting the volume ratio of the second inorganic particles to the volume ratio of the first inorganic particles to 0.10 to 0.15, a slurry that can be used for high-precision optical modeling technology can be obtained. Can be done.

According to the slurry of the present invention, the slurry can be applied to the molding stage of the stereolithography apparatus in a stable state with little dependence of the viscosity on the shearing speed in the high-speed region.

<Conclusion>
In the photocurable resin, fine first inorganic particles of 1 to 5 [μm] and particles having a particle size of 0.22 times or less and 0.05 times or more the particle size of the first inorganic particles are used. By mixing and dispersing the two inorganic particles, a slurry having good thixotropic properties can be obtained.
The obtained slurry is applied at a shear rate of 10 [1 / s] or more in a stereolithography apparatus to form a thin slurry layer of 5 to 200 [μm], and scanned into a predetermined pattern by laser light. By repeating the above steps, a photocured product of the cured slurry patterned into a high-definition three-dimensional shape can be produced. By degreasing and sintering a photocured product having a three-dimensional structure in which the slurry is cured, a three-dimensional stereolithographic product can be produced with good reproducibility.

According to the present invention, it is possible to provide a slurry for producing a high-definition three-dimensional model and a method for producing a stereolithography using the slurry, and the industrial applicability is high.

1 Slurry 1a Slurry layer 2 Dispenser 3 Auxiliary table 4 Recoater 5 Modeling table 5a Modeling surface 6 Hardened layer

Claims (6)

It contains a first inorganic particle, a second inorganic particle, and a photocurable resin.
The average particle size of the first inorganic particles is 1 to 5 [μm].
The average particle size of the second inorganic particles is 0.22 times or less the average particle size of the first inorganic particles.
The volume ratio of the second inorganic particles to the first inorganic particles is 0.01 or more.
The viscosity at a shear rate of 10 [1 / s] is 50 [Pa · s] or less.
The viscosity at a shear rate of 0.01 [1 / s] is 500 [Pa · s] or more.
A slurry for stereolithography characterized by this. The slurry for stereolithography according to claim 1, wherein the volume ratio of the first inorganic particles is equal to or greater than a solidification limit value. The slurry for stereolithography according to claim 1 or 2, wherein the volume ratio of the first inorganic particles and the second inorganic particles combined is 65 to 70 [vol%]. The slurry for stereolithography according to any one of claims 1 to 3, wherein the volume ratio of the second inorganic particles to the first inorganic particles is 0.10 to 0.15. The first step of discharging the stereolithography slurry according to any one of claims 1 to 4, and the first step.
The second step of stretching the stereolithography slurry to form a slurry layer having a thickness of 5 to 200 [μm], and
A third step of scanning the slurry layer into a predetermined pattern shape and irradiating the slurry layer with laser light.
A step of forming a photocured product from the slurry layer by repeating the first, second and third steps, and
The first heat treatment step of heat-treating the photocurable product to remove the photocurable resin, and
A method for producing a stereolithographic product, which comprises a second heat treatment step of heat-treating and sintering the photocured product after the first heat treatment step. The method for producing a stereolithographic product according to claim 5, wherein the temperature of the slurry is maintained at 35 to 60 [° C.] in the first step or the first step and the second step.

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