JP2005067998A - Slurry for optical three-dimensional shaping, method for fabricating optical three-dimensional shaped article, and optical three-dimensional shaped article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the dimensional preciseness of an optical three-dimensional shaped article by reducing shrinkage caused by photocuring and electric characteristics, especially dielectric characteristics. <P>SOLUTION: By modifying the surface of a ceramic powder to improve its dispersibility in a photocurable resin, an increase of viscosity of the resin is suppressed to make the optical three-dimensional shaping possible even when the ceramic powder is filled at a high density and the volume shrinkage in photocuring is suppressed to improve the dimensional preciseness. By filling the photocurable resin with a dielectric ceramic powder, an optical three-dimensional shaped article having excellent dielectric characteristics is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical three-dimensional modeling slurry used for optically modeling a three-dimensional object, an optical three-dimensional object manufacturing method, and an optical three-dimensional object obtained by this method.

  A conventional method for producing an optical three-dimensional object using a photocurable resin is to apply light so that a desired pattern can be obtained on the surface of a liquid photocurable resin composition mainly composed of a photocurable resin. Selectively irradiate and cure one layer with a predetermined thickness. Then, a liquid photocurable resin composition for the next layer is supplied onto the cured layer, and the lamination operation of obtaining a continuous cured layer by selectively irradiating light similarly is repeated. A three-dimensionally shaped object having a simple shape is obtained.

  This method for producing an optical three-dimensional object has attracted particular attention in recent years because a three-dimensional object having a considerably complicated shape can be obtained easily and in a relatively short time.

  Photo-curing resins generally have low mechanical strength such as tensile strength and bending strength and insufficient thermal resistance compared to commonly used thermosetting resins. It is difficult to use for a three-dimensional molded article that requires resistance. For this reason, it was used only for three-dimensional shaped objects such as models, but by adding a filler to the photocurable resin, the mechanical strength and thermal resistance of the three-dimensional shaped object can be improved, so that the injection Its uses have expanded, such as shaping molding molds.

  In the manufacturing method of an optical three-dimensional object, an extremely complicated shape can be formed with good dimensional accuracy, so that the optical three-dimensional object itself has one function as an electronic device such as an antenna or a filter. Be expected.

  In order to use the optical three-dimensional model as an electronic device, it is desired to improve the electrical characteristics, particularly the dielectric characteristics and the dimensional accuracy of the optical three-dimensional model.

  It is known that the photocurable resin shrinks at the time of curing, and this shrinkage affects the dimensional accuracy of the optical three-dimensional object. In order to reduce the shrinkage at the time of curing, it is conceivable to fill the solid content more with a photocurable resin. And in order to improve the electrical property of a three-dimensional molded item, especially a dielectric property, what is necessary is just to fill more photodielectric resin etc. with dielectric ceramics.

  There are many disclosures about adding fillers such as ceramics to a photocurable resin (see, for example, Patent Documents 1 and 2).

  However, when the ceramic powder and the photocurable resin are simply mixed, the ceramic surface and the photocurable resin are not easily adapted, and the ceramic powder is not uniformly dispersed in the photocurable resin. For this reason, there exists a problem that the viscosity of the photocurable resin composition filled with ceramic powder increases (for example, refer nonpatent literature 1). As a result, an optical three-dimensional object with excellent dimensional accuracy could not be obtained.

Then, the slurry composition which mixed the ceramic powder surface-treated with the silane compound, the photocurable resin, and the organic solvent, and reduced the viscosity is proposed (for example, refer patent document 3).
Japanese Patent Publication No. 7-42482 JP 2000-341031 A JP-A-8-12242 Academic biography, Taro Takagi, Kazuyuki Yanagisawa, Naomasa Nakajima “Journal of Precision Engineering” vol. 61, no. 3, 1995, p420-424

  However, even if the ceramic powder is surface-treated with a silane compound, it has been found that the improvement in dispersibility is limited with the silane compound. For this reason, it was found that when the ceramic powder was highly filled, the viscosity of the photocurable resin composition increased and gelled. In Patent Document 3 described above, since a solvent is added even in a small amount, it takes time to remove the solvent. Further, when the solvent is dried, pores (holes) are generated and volume shrinkage occurs, so that a molded article having a desired shape cannot be obtained, and problems such as warping of the molded article occur.

  Furthermore, when a solvent is contained, there is a high possibility that the photocurable resin is cured and the reaction of three-dimensional crosslinking is suppressed, and optical three-dimensional modeling may be difficult.

  The present invention has been made in view of the above points, and provides an optical three-dimensional modeling slurry that suppresses viscosity and shrinkage at the time of curing, thereby improving the dimensional accuracy. The main purpose is to obtain a model.

  The present invention is configured as follows in order to achieve the above-described object.

  That is, the optical three-dimensional modeling slurry of the present invention is a slurry composed of a ceramic powder and a photocurable resin, and has a volume shrinkage ratio of 4.3% or less during photocuring.

  The ceramic powder is preferably a dielectric ceramic powder.

  According to the present invention, a ceramic powder is filled in a photocurable resin to make a volumetric shrinkage ratio at the time of photocuring of 4.3% or less, so that it is an optical three-dimensional modeling slurry. The dimensional accuracy of a three-dimensional molded item can be improved.

  In particular, when the ceramic powder is a dielectric ceramic powder, it is possible to improve the dielectric properties of an optical three-dimensional object that is formed using this slurry.

  In a preferred embodiment of the present invention, the surface of the ceramic powder is wet-treated with a comb-type polymer dispersant, the concentration of the ceramic powder is 38.0 vol% or more and 57.5 vol% or less, and the photocuring property. The concentration of the resin is 42.5 vol% or more and 62.0 vol% or less.

  Here, the photocurable resin preferably contains a polymerization initiator. Moreover, it is preferable that the slurry for optical three-dimensional modeling does not contain the solvent etc. which are used in order to disperse ceramic powder in a photocurable resin.

  If the concentration of the ceramic powder is less than 38.0 vol% and the concentration of the photocurable resin exceeds 62.0 vol%, the volume shrinkage rate at the time of photocuring increases, and deviates from the range of claim 2, Dimensional accuracy deteriorates. Further, when the dielectric ceramic powder is used, the dielectric ceramic powder in the slurry has a small filling amount, so that the dielectric characteristics are low and it is difficult to use it as an electronic device.

  Conversely, when the concentration of the ceramic powder exceeds 57.5 vol% and the concentration of the photocurable resin is less than 42.5 vol%, the viscosity of the slurry becomes very high, and the method for producing an optical three-dimensional object of the present invention The optical three-dimensional modeling by becomes difficult.

  According to this embodiment, it is possible to improve the dimensional accuracy of an optical three-dimensional object formed using this slurry, and in particular, it is possible to obtain an optical three-dimensional object having no pores by not containing a solvent. . Further, by using the dielectric ceramic powder, it is possible to improve the dielectric properties of the optical three-dimensional structure and use it as an electronic device.

  In one embodiment of the present invention, preferably, the surface of the ceramic powder is wet-treated with a comb-type polymer dispersant.

  According to this embodiment, since the surface of the ceramic powder is wet-treated with the comb polymer dispersant, the familiarity between the surface of the ceramic powder and the photocurable resin is improved. Further, the dispersibility is improved by the steric repulsion between the long side chains of the comb polymer dispersant, and the viscosity of the slurry can be reduced.

  The manufacturing method of the optical three-dimensional model | molding of this invention supplies the said slurry for optical three-dimensional model | molding on the hardening layer of the slurry for optical three-dimensional model | molding of this invention, and the upper surface of the slurry for optical three-dimensional model | molding supplied. Is smoothed with a squeegee to form an uncured layer of slurry for optical three-dimensional modeling with a predetermined thickness, and this uncured layer is irradiated with light and cured in a desired pattern to form a cured layer for one layer. And this is sequentially repeated over a plurality of layers for modeling.

  It is preferable to supply the optical three-dimensional modeling slurry onto the hardened layer from above the hardened layer. Moreover, you may perform the supply of the optical three-dimensional modeling slurry on a hardened layer by application | coating.

  The predetermined thickness does not have to be constant for all of the plurality of layers.

  In the conventional method for manufacturing an optical three-dimensional object, as shown in FIG. 2A, the surface of the optical three-dimensional object slurry 10 in the slurry tank 11 is irradiated with light such as a laser beam 12. The elevating stage 14 that supports the cured layer 13 is lowered by one layer in the slurry tank 11 as shown in FIG. The optical three-dimensional modeling slurry 10 is supplied by being poured.

  For this reason, when the viscosity of the optical three-dimensional modeling slurry 10 increases, even if the stage 14 is lowered by one layer in the slurry tank 11, the optical three-dimensional modeling slurry 10 is formed on the upper surface of the cured layer 13 on the stage 14. Will not flow in and will not be able to supply.

  According to the present invention, there is no need to lower the stage in the slurry tank and flow the optical three-dimensional modeling slurry onto the stage and supply the optical three-dimensional modeling slurry onto the stage, for example, from above. By supplying and smoothing with a squeegee, an uncured layer having a predetermined thickness is formed, which is suitable for a slurry for optical three-dimensional modeling that is highly filled with ceramic powder as in the present invention.

  The optical three-dimensional structure of the present invention is formed by the method for manufacturing an optical three-dimensional structure of the present invention.

  According to the present invention, it is possible to obtain an optical three-dimensionally shaped article having a low volume shrinkage during curing and an improved dimensional accuracy.

  As one embodiment of the method for producing an optical three-dimensional object of the present invention, preferably, a peripheral wall is simultaneously formed around the object.

  In the case of this embodiment, since the peripheral wall to be molded simultaneously confines the uncured resin, when there is no peripheral wall, the uncured resin flows downward, and the shoulder portion of the molded object is rounded during photocuring It is possible to avoid the problem of being formed. As a result, it is possible to obtain an optical modeling object with higher accuracy as designed.

  Moreover, as one embodiment of the manufacturing method of the optical three-dimensional molded item of this invention, Preferably, it presses with respect to the said optical three-dimensional molded item before the process of baking the modeled optical three-dimensional molded item. Degrease.

  In the case of this embodiment, by performing the pressure-type degreasing treatment, the surface of the fired body is free from cracks and does not collapse, and a dense sintered body can be obtained.

As described above, according to the present invention, it is possible to obtain an optical three-dimensional modeled object with improved dimensional accuracy. Further, by using the surface-modified ceramic powder, it is possible to suppress an increase in viscosity even if the photocurable resin is highly filled, and it becomes easy to form a three-dimensional model with high accuracy.

  Furthermore, by using a dielectric ceramic powder, an optical three-dimensional modeled article having excellent dielectric characteristics and a high relative dielectric constant can be obtained. Therefore, the optical three-dimensional modeled object having excellent dielectric characteristics can be used as an electronic device having a complicated shape, and the miniaturization and high functionality can be achieved.

Hereinafter, the present invention will be described in more detail.
The slurry for optical three-dimensional model | molding of this invention consists of ceramic powder and photocurable resin, and the volumetric shrinkage rate at the time of photocuring is 4.3% or less.

  If the volume shrinkage during photocuring exceeds 4.3%, an optical three-dimensional object with a desired size may not be obtained, and warping may occur.

  The ceramic powder used in the present invention is not particularly limited, and examples thereof include various ceramic powders such as barium titanate, strontium titanate, calcium titanate, magnesium titanate, aluminum oxide, titanium oxide, and magnesium silicate. Can be used.

  This ceramic powder is not limited to a single type, and may be used as a mixture of two or more types. Moreover, the average particle diameter of ceramic powder is 0.5-50 micrometers, for example.

  The ceramic powder is preferably modified by treating its surface in order to improve the familiarity with the photo-curable resin and enhance the dispersibility.

  As a method for modifying the surface of the ceramic powder, there is a method in which a comb-type polymer dispersant is adsorbed on the surface of the ceramic powder. There are cationic, anionic, and nonionic dispersants, which are appropriately selected depending on the type of ceramic powder.

  There are a dry surface treatment method and a wet surface treatment method as methods for adsorbing the dispersant on the surface of the ceramic powder.

  The dry surface treatment method is a method in which only a predetermined amount of ceramic powder and a surface modifier are directly mixed and stirred. The wet surface treatment method is a method in which a surface modifier is dissolved in a solvent, ceramic powder is added to the mixed solution, and after stirring, the mixed solution is removed by filtration.

  As a method for treating ceramic powder with a dispersant, a wet surface treatment method is preferred. This is because the wet surface treatment method can adsorb the dispersant on the entire surface of the ceramic powder.

  Ceramic powder and photo-curing resin are very different in polarity, so it is difficult to get used to each other. For this reason, if the filling amount of the ceramic powder in the photocurable resin increases, the ceramic is likely to agglomerate, and the viscosity of the photocurable resin composition filled with the ceramic powder, that is, the slurry for optical three-dimensional modeling is reduced. It will increase.

  However, the presence of a comb-type polymer dispersant having a polarity similar to that of a photocurable resin on the ceramic powder surface improves the wettability and compatibility of the ceramic powder with the photocurable resin, making it easier to become familiar with. Dispersibility is improved.

  As the dispersant, those having a comb (comb) type molecular structure with long side chains are preferable. The comb-type polymer dispersant adsorbed on the surface of the ceramic powder causes steric repulsion between the ceramic particles and contributes to the improvement of dispersibility by trying to separate from each other.

  The surface treatment method of the ceramic powder with the comb polymer dispersant is preferably a wet treatment method as described above.

  This is because, in the wet processing method, the comb-type polymer dispersant is dissolved in a solvent and made uniform, and then the ceramic powder is added. Therefore, the entire surface of the ceramic powder can be coated with the comb-type polymer dispersant. When the ceramic surface not coated with the comb-type polymer dispersant comes into contact with the photocurable resin, it causes an interaction and increases the slurry viscosity, which may make optical three-dimensional modeling difficult.

  Examples of the comb polymer dispersant include a copolymer having a polyoxyalkylene alkenyl ether unit and a maleic acid compound unit as essential monomer units.

  The photocurable resin used in the present invention is not particularly limited, and for example, an epoxy resin, a (urethane) acrylate resin, an oxetane resin, and the like can be used.

  Examples of acrylate resins include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, propylene glycol acrylate, acrylamide, vinyl acetate, styrene, diurethane diacrylate, 1,6-hexanediol diacrylate, diol diacrylate, and diethylene glycol diacrylate. , Triethylene glycol diacrylate, polyethylene glycol diacrylate, nonanediol diacrylate, ethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, dicyclo Pentenyl diacrylate, polyester diacrylate, diallyl phthalate And the like can be given.

  Examples of the epoxy resin include hydrogenated bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 2- (3,4 epoxyepoxycyclohexyl-5,5-spiro-3, 4-epoxy) cyclohexane-m-dioxane, bis (3,4-epoxycyclohexylmetal) adipate, and the like.

  The photocurable resin preferably contains a photopolymerization initiator, but may not contain it. In this case, a photopolymerization initiator is added to the slurry.

  It is preferable that the slurry for optical three-dimensional modeling of the present invention does not contain a ceramic powder, a solvent other than the photocurable resin, an additive, and the like.

  In the slurry for optical three-dimensional modeling of the present invention, the concentration of the ceramic powder is 38.0 vol% or more and 57.5 vol% or less, and the concentration of the photocurable resin is 42.5 vol% or more and 62.0 vol% or less. Is preferred.

By increasing the filling amount of the ceramic powder, the volume shrinkage rate at the time of photocuring is reduced, and the dimensional accuracy of the three-dimensional object to be formed using the optical three-dimensional object slurry of the present invention is improved. Further, by using the dielectric ceramic powder, the relative permittivity of the three-dimensional structure is increased at the same time, and application as a functional device becomes possible. The relative dielectric constant is preferably 4 to 30, for example.
Here, the manufacturing method of the optical three-dimensional molded item of this invention is demonstrated based on FIG.

  This FIG. 1 has shown the state in the middle of the shaping | molding by the manufacturing method of an optical three-dimensional molded item, The figure (a) shows the state in which the multilayered hardening layer 2 was formed on the stage 1. FIG. ing.

  In the manufacturing method of the optical three-dimensional modeled object of this embodiment, the optical three-dimensional modeled slurry of the present invention is dropped onto the cured layer 2 from, for example, the upper side or applied and supplied, and the uncured layer 3 is formed.

  Next, as shown in FIG. 2B, the surface of the uncured layer 3 is smoothed by moving the squeegee 4 at a predetermined height from the surface of the cured layer 2 as indicated by the arrow. Thus, the uncured layer 3 having a predetermined thickness is formed.

  Next, as shown in FIG. 2C, the uncured layer 3 having a predetermined thickness is irradiated with light such as a laser beam 5 in a desired pattern to form a cured layer 2 for one layer. To do.

  Thereafter, similarly, the steps (a) to (c) are sequentially repeated to obtain an optical three-dimensional object having a desired shape.

  Thus, in the manufacturing method of the optical three-dimensional molded item of the present invention, the upper surface of the uncured layer 3 supplied onto the cured layer 2 is smoothed with the squeegee 4 so that the uncured layer 3 having a predetermined thickness is formed. To form. Therefore, by lowering the stage in the slurry tank, the slurry flows into the cured layer on the stage to form an uncured layer for one layer, so the viscosity of the slurry is high. Even if the slurry does not flow onto the hardened layer and modeling is impossible, modeling can be performed according to the method of this embodiment.

  According to the method for manufacturing an optical three-dimensional structure of this embodiment, for example, even when the viscosity is 250 to 300 (Pa · s) and the slurry is slightly high when the shear rate is 1 (1 / s), A sufficiently complex shape can be formed.

  In order to apply the method for manufacturing an optical three-dimensional object of the present invention, the optical three-dimensional object molding slurry of the present invention has a viscosity at a shear rate of 1 (1 / s) of 10 (Pa · s) or more and 300. It is preferable to be in the range of (Pa · s) or less.

  Since the viscosity is low when the value is lower than 10 Pa · s, after adjusting the thickness of the uncured layer with the squeegee, the slurry flows down to the surroundings with the passage of time, and the molding of a predetermined thickness is formed. It becomes difficult and affects the dimensional accuracy.

  In addition, when the value is higher than 300 Pa · s, it becomes difficult to prepare the slurry. Even if it can be blended, the viscosity is high, so that the slurry does not stretch, and it becomes difficult to supply a slurry having a predetermined uniform thickness over the entire upper surface of the cured layer.

  Moreover, there is a method shown in FIG. 2 as an example of the manufacturing method of the optical three-dimensional structure of the present invention.

  FIG. 2A shows a state in which a plurality of hardened layers 22 are formed on the stage 21 and a state in which a peripheral wall 23 is also formed around the hardened layer 22 at the same time. The peripheral wall 23 is formed by curing the uncured slurry at the same time when the cured layer 22 of each layer is formed from when the first cured layer 22 is formed on the stage 21. The uncured slurry before the curing treatment is supplied by dropping or applying the optical three-dimensional modeling slurry of the present invention onto the cured layer 22 previously formed by, for example, the material ejector 24 from above. Then, the uncured layer 25 is formed.

  Next, as shown in FIG. 5B, the surface of the uncured layer 25 is smoothed by moving the squeegee 26 at a predetermined height from the surface of the cured layer 22 as indicated by an arrow. As a result, the uncured layer 25 having a predetermined thickness is formed.

  Next, as shown in FIG. 3C, the hardened layer 22 for one layer is formed in a desired pattern with light such as laser light 27 on the uncured layer 25 having a predetermined thickness. Further, in the step of forming the hardened layer 22, the peripheral wall 23 is hardened and formed by irradiating the uncured layer 25 with the laser beam 27 around the hardened layer 22 around the front, rear, left and right of the hardened layer 22 to be formed. .

  Thereafter, similarly, the steps (a) to (c) are sequentially repeated to obtain an optical three-dimensional object having a desired shape. At this time, the peripheral wall 23 and the hardened layer 22 are formed at the same height in the step of forming each layer. In addition, it is preferable to start irradiation with the laser beam 27 from the peripheral wall 23 immediately after the surface of the uncured layer 25 is smoothed by the squeegee 26 of the doctor blade, and photocuring. This can prevent the uncured slurry from flowing out. Moreover, if the resin material between the cured product 22 and the peripheral wall 23 to be a modeled product is left uncured, the modeled product and the peripheral wall 23 can be easily separated.

  In this way, comparing the case where the peripheral wall 23 is also formed to manufacture the modeled object and the case where the modeled object is manufactured without providing the peripheral wall, in the direction having the peripheral wall 23, as shown in FIG. Edges were clearly formed on the shoulder portion of the cured product 22 to be a modeled product, and the modeled product could be obtained with dimensional accuracy almost as designed without causing any chipping in the modeled product.

  On the other hand, when a modeled object is manufactured without providing a peripheral wall, as shown in FIG. 4B, the tendency to flow outward and downward at the peripheral portion of the uncured resin before the photocuring treatment is performed. Therefore, the shoulder portion of the cured product 32 that becomes a modeled object is in a rounded state, and the modeled object is chipped, resulting in a shape that is 30% lower in accuracy than the design dimension.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited at all by this Example.

(Example 1)
13.5 g of an anionic comb-type polymer dispersant, specifically, a polyoxyalkylene alkenyl ether unit and a maleic acid compound unit as essential monomer units (10.10 calcium titanate). (Corresponding to 0% by weight) was completely dissolved in 450.00 g of ethanol. To this, 135.00 g of calcium titanate was added and dispersed in an ultrasonic bath for 30 minutes, and then allowed to stand overnight to adsorb the anionic comb-type polymer dispersant onto the calcium titanate surface.

  Next, the precipitate accumulated at the bottom of the container was stirred and redissolved in the supernatant solution, and filtered with suction to remove the ethanol solvent. After the powder obtained by filtration was dried all day and night, the powder crushed for 10 seconds by an all-purpose pulverizer (IKA mill manufactured by IKA) was heated in an oven at 60 ° C. for 3 hours to evaporate the remaining ethanol. Thus, calcium titanate surface-modified with an anionic comb-type polymer dispersant by a wet surface treatment method was obtained.

  The surface-modified calcium titanate 120.00 g of urethane acrylate photocurable resin, specifically, diurethane dimethacrylate is added, and the filling amount of calcium titanate in the slurry for optical three-dimensional modeling is 45.0 vol. %. After preliminary stirring with a spatula, stirring / defoaming was performed for 1 minute with a stirring defoaming device (manufactured by Keyence Corporation), and the surface-modified calcium titanate was uniformly dispersed to obtain a slurry for optical three-dimensional modeling.

  Using this slurry for optical three-dimensional modeling, modeling was performed by the manufacturing method of the optical three-dimensional modeled object of the present invention shown in FIG. 1 described above to produce a 10 mm × 10 mm × 1 mm rectangular parallelepiped.

  That is, an appropriate amount of this optical three-dimensional modeling slurry is applied on the stage of the optical three-dimensional modeling machine, the upper surface is smoothed with a squeegee 30 μm above the stage, and the upper surface of the optical three-dimensional modeling slurry is 10 mm × 10 mm with ultraviolet rays. Draw a square. Next, the cured layer was laminated by lowering the stage by 30 μm and repeating the same operation, and finally the layer was laminated at 10 μm to form a thickness of 1 mm. The volume shrinkage after photocuring of the obtained cuboid was calculated and found to be 3.8%.

Here, the volume shrinkage was calculated as follows. That is,
The specific gravity (S1) of the slurry for optical three-dimensional modeling and the specific gravity (S2) of the photocured product were measured, and the volume shrinkage was determined from the following formula (1). The specific gravity (S1) of the slurry for optical three-dimensional modeling was measured using a specific gravity bottle, and the specific gravity (S2) of the photocured product was measured by an underwater substitution method.

Volume shrinkage = [1- (S1 / S2)] × 100 Formula (1)
(Example 2)
In place of calcium titanate, aluminum oxide was used, and aluminum oxide surface-modified with an anionic comb-type polymer dispersant by a wet surface treatment method was obtained in the same manner as in Example 1.

  Using this surface-modified aluminum oxide, a slurry for optical three-dimensional modeling was obtained in the same manner as in Example 1 except that the filling amount was 57.5 vol%.

  A 10 mm × 10 mm × 1 mm rectangular parallelepiped was produced using this three-dimensional modeling slurry in the same manner as in Example 1, and the volume shrinkage after photocuring of the obtained rectangular solid was calculated to be 2.9%. It was.

(Example 3)
A slurry for optical three-dimensional modeling was obtained in the same manner as in Example 1 except that the filling amount of the surface-modified calcium titanate was 38.0 vol%.

  A 10 mm × 10 mm × 1 mm rectangular parallelepiped was produced in the same manner as in Example 1 using this three-dimensional modeling slurry, and the volume shrinkage after photocuring of the obtained rectangular parallelepiped was calculated to be 4.3%. It was.

Example 4
A slurry for optical three-dimensional modeling was obtained in the same manner as in Example 1 except that the filling amount of the surface-modified calcium titanate was 52.0 vol%.

A 10 mm × 10 mm × 1 mm rectangular parallelepiped was produced using this three-dimensional modeling slurry in the same manner as in Example 1, and the volume shrinkage ratio after photocuring of the obtained rectangular parallelepiped was calculated to be 3.3%. It was.
(Comparative Example 1)
A slurry for optical three-dimensional modeling was obtained in the same manner as in Example 1 except that calcium titanate not subjected to surface modification was used and the filling amount was changed to 37.0 vol%.

  Using this slurry for three-dimensional modeling, a rectangular parallelepiped of 10 mm × 10 mm × 1 mm was produced in the same manner as in Example 1, and the volume shrinkage ratio after photocuring of the obtained rectangular parallelepiped was calculated to be 4.4%. It was. This resulted in a large volume shrinkage, warpage, and a problem in size.

(Comparative Example 2)
The surface-modified calcium titanate was obtained in the same manner as in Example 1. To this surface-modified calcium titanate, the same urethane acrylate photocurable resin as in Example 1 was added, and the slurry was prepared such that the calcium titanate filling amount of the slurry for optical three-dimensional modeling was 60.0 vol%.

  After pre-stirring with a spatula, stirring / defoaming was carried out for 1 minute using a stirring deaerator (manufactured by Keyence Corporation). However, the slurry is gelled, and it is in a state in which one layer of slurry cannot be supplied onto the cured layer, and optical three-dimensional modeling is impossible. Therefore, the volume shrinkage rate could not be measured. At 60.0 vol%, a slurry suitable for the optical three-dimensional modeling method could not be prepared.

(Comparative Example 3)
The calcium titanate powder which gave the silane coupling agent process as follows was obtained. Acetic acid 5 g was added to 495 g of pure water to prepare a 1% aqueous acetic acid solution. 225 g of this 1% aqueous acetic acid solution and 225 g of isopropyl alcohol were mixed to prepare a 50% aqueous acid / alcohol solution. To this 50% acid / alcohol aqueous solution, 1.35 g of a silane coupling agent (1.0% by weight of calcium titanate) was added and stirred to prepare a treatment solution.

  While this treated solution was stirred with a propeller stirrer, 120.0 g of calcium titanate was added little by little. After the entire amount was added, stirring was continued for 30 minutes. Then, it filtered by suction and the solvent was removed. The powder obtained by filtration was dried for a whole day and night, and then pulverized for 10 seconds by a universal pulverizer (IKA mill manufactured by IKA). The crushed powder was heated in an oven at 100 ° C. for 3 hours to evaporate the remaining ethanol, and the calcium titanate surface and the silane coupling agent were chemically reacted to strengthen the bond. Thus, calcium titanate surface-modified with a silane coupling agent by a wet surface treatment method was obtained.

  The same urethane acrylate photocurable resin as in Example 1 was added to 120.00 g of calcium titanate treated with a silane coupling agent, and the mixture was prepared so that the calcium titanate filling amount of the slurry for optical three-dimensional modeling was 45 vol%. .

  After pre-stirring with a spatula, stirring / defoaming was carried out by a stirring defoaming device (manufactured by Keyence Corporation) every minute, but it was gelled and became a very viscous slurry. In the optical three-dimensional modeling method, the slurry must be applied to a thickness of several microns to several hundred microns. However, in the case of the one treated with the silane coupling agent, it is gelled and very difficult to apply. Molding by was not possible.

  Table 1 shows the types of ceramic powder, the surface treatment method of the ceramic powder, the solvent, the concentration of the ceramic powder, the volumetric shrinkage, and the state of the cured product for Examples 1 to 4 and Comparative Examples 1 to 3.

この表１および上述の説明から明らかなように、光硬化時の体積収縮率が、４．３％以下の実施例１〜４では、溶剤を添加することなく、セラミックス粉末を３８．０ｖｏｌ％以上の高い濃度で充填することができた。しかも、粘度の増加を抑制することができ、反りの無い立体造形物を得ることができた。

As is clear from Table 1 and the above description, in Examples 1 to 4 in which the volume shrinkage ratio during photocuring is 4.3% or less, the ceramic powder is added to 38.0 vol% or more without adding a solvent. Can be filled at a high concentration. Moreover, an increase in viscosity can be suppressed, and a three-dimensionally shaped object without warping could be obtained.

  As described above, the ceramic powder can be filled at a high concentration of 38.0 vol% or more, so that the relative dielectric constant is high and the dielectric characteristics required for the electronic device can be obtained.

  On the other hand, in Comparative Examples 1 to 3 in which the volume shrinkage after photocuring exceeds 4.3%, the three-dimensional modeled object after photocuring is warped or the slurry is gelled. As a result, it was impossible to form a three-dimensional model.

  Further, by comparing Example 1 treated with a comb-type polymer dispersant with the same concentration of calcium titanate and Comparative Example 3 treated with a silane coupling agent, it was possible to produce a slurry for optical three-dimensional modeling. It can be seen that a comb-type polymer dispersant is more suitable as a surface modifier for ceramic powder than a silane coupling agent.

  Next, an embodiment of a method for forming a peripheral wall surrounding a cured layer at the same time as forming a cured layer will be described as a method for producing an optical three-dimensional model according to the present invention. An optical modeling thing was produced based on the above-mentioned optical modeling method, forming the peripheral wall 23 shown in Drawing 2 and Drawing 3 using dielectric slurry for optical modeling produced according to the above-mentioned example 4. The firing condition of this stereolithography is up to 380 ° C., filled with nitrogen in the furnace, pressurized to 0.5 MPa, pressurized degreasing treatment, up to 1700 ° C., flowing 1 liter / min of air, and reaches 1700 ° C. The temperature was maintained for 2 hours from that time. The sintered body of the optical modeling thing was obtained through the above process. The size of the obtained fired body was contracted to about 80%, and the volume was contracted to about 52%. When the calcined product obtained by performing this pressure degreasing and the calcined product obtained by performing normal pressure degreasing separately for comparison with the calcined product obtained by performing the pressure degreasing, the calcined product and the internal delamination are obtained in the calcined product of pressure degreasing. On the other hand, in the normal pressure degreasing fired body, it was confirmed that the sintered body swelled in the stacking direction, cracks were generated on the surface thereof, and many internal delaminations were generated.

  Therefore, the fired body obtained by the manufacturing method according to the present invention of Example 2 had no cracks on the surface and was not broken. This is considered to be because sintering has progressed because 52% by volume of alumina is contained in the optically shaped article before firing. The reason why the fired body did not swell or peeled between layers was that pressure degreasing was performed, and it is considered that the volume of the resin decomposition gas could be reduced by the pressure degreasing. Since the volume after firing was shrunk to 52 vol%, the resin completely flew away, the sintered state was good, and a dense sintered body could be obtained.

It is a vertical side view which shows the process of the manufacturing method of the optical three-dimensional molded item which concerns on one embodiment of this invention. It is a vertical side view which shows the process of the manufacturing method of the optical three-dimensional molded item which concerns on another embodiment of this invention. It is the schematic diagram which looked at the stereolithography thing and peripheral wall in the process of the manufacturing method shown in FIG. 2 from the top. It is a vertical side view which shows the manufacturing process (a) in the manufacturing method shown in FIG. 2, and the manufacturing process (b) of the comparative example. It is a vertical side view which shows the manufacturing method of the conventional optical three-dimensional molded item.

Explanation of symbols

1,14 Stage 2,13 Cured layer 3 Uncured layer 4 Squeegee 5,12 Laser beam

Claims (6)

A slurry for optical three-dimensional modeling, comprising a ceramic powder and a photocurable resin, and having a volume shrinkage ratio of 4.3% or less upon photocuring. The surface of the ceramic powder is wet-treated with a comb polymer dispersant, the concentration of the ceramic powder is 38.0 vol% or more and 57.5 vol% or less, and the concentration of the photocurable resin is 42 The slurry for optical three-dimensional model | molding of Claim 1 which is 0.5 vol% or more and 62.0 vol% or less. The optical three-dimensional modeling slurry is supplied onto the cured layer of the optical three-dimensional modeling slurry according to claim 1 or 2, and the upper surface of the supplied optical three-dimensional modeling slurry is smoothed with a squeegee. By forming an uncured layer of the slurry for optical three-dimensional modeling with a predetermined thickness, the uncured layer is irradiated with light and cured in a desired pattern to form a cured layer for one layer. A method for producing an optical three-dimensional modeled object, characterized by sequentially repeating modeling over layers. 4. The method for manufacturing an optical three-dimensional object according to claim 3, wherein a peripheral wall is simultaneously formed around the three-dimensional object. An optical three-dimensional object formed by the method for manufacturing an optical three-dimensional object according to claim 3 or 4. Prior to the step of firing the optical three-dimensional object formed by the method of manufacturing an optical three-dimensional object according to claim 3 or 4, pressure degreasing is performed on the optical three-dimensional object. The manufacturing method of the optical three-dimensional molded item.

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