KR20220058795A - Multi-color photocurable slurry mixture, method for manufacturing the same, and method for manufacturing gradient functional ceramic structure and gradient functional ceramic structure manufactured thereby - Google Patents

Abstract

The present application is a mixture of two or more slurry compositions comprising zirconia powder, a photocurable monomer, a diluent and a dispersant, and provided is a multi-color photocurable slurry mixture, wherein the two or more slurry compositions have different colors, and a ratio of viscosity to a shearing rate 1/s is 1:3 to 3:1. Therefore, in a 3D printing process, delamination phenomenon does not occur even when color gradient changes.

Description

Multi-color photocurable slurry mixture, method for manufacturing same, and method for manufacturing gradient functional ceramic structure and gradient functional ceramic structure prepared thereby {Multi-color photocurable slurry mixture, method for manufacturing the same, and method for manufacturing gradient functional ceramic structure and gradient functional ceramic structure manufactured thereby}

The present application relates to a multi-color photocurable slurry mixture capable of manufacturing a ceramic structure whose composition is continuously changed using 3D printing technology, a method for preparing the same, and a method for manufacturing a gradient functional ceramic structure and a gradient functional ceramic structure manufactured by the same will be.

As the development and possibility of 3D printing technology rises, development in various fields is being made. This technology can implement complex shapes quickly and precisely, and the emergence and research of various printing technologies in recent years is showing rapid development in precision fabrication of tooth shapes. Among them, DLP (Digital Light Processing)-based 3D printing technology has the advantage of being able to quickly and precisely implement a shape using a photocurable slurry composition.

Thanks to the precise shape control of 3D printing and the high physical and esthetic properties of zirconia, 3D printing based on zirconia slurry actively led the development of artificial teeth with the advent of technology. Gold, titanium, and zirconia are widely used materials for the production of artificial teeth. Gold, titanium, etc., which have been widely used in the past, showed excellent results in terms of physical properties and biocompatibility, but their esthetics were relatively poor. There is an increasing demand for zirconia artificial teeth that can satisfy all these requirements.

However, since human teeth are not made of a single color, when a person actually uses artificial teeth of a single color, comparing them with the original teeth may give a heterogeneous feeling. The enamel of the teeth is close to white, and the dentin is slightly yellow compared to the enamel. Therefore, if artificial teeth with slanted functional color tones are manufactured to display the same color as actual teeth, the sense of heterogeneity is reduced, and the esthetics are high and it is difficult to distinguish them from real teeth.

In order to overcome this phenomenon, a process of manufacturing a single-color zirconia material-based artificial tooth and then applying a color thereon is being implemented, but the addition of this process lengthens the production period and at the same time increases the production cost to consumers and suppliers. At the same time, it is burdensome. If the desired color is realized immediately after sintering through the tilt function type 3D printing technology, it is expected that the above side effects will be easily resolved and the overall accessibility will be very easy.

The present invention provides a slurry mixture capable of producing a ceramic structure of various colors and a technique for controlling the rheological behavior and photocurability of the slurry mixture by searching for and selecting various materials for preparing the same.

In addition, in order to precisely 3D print zirconia artificial teeth having a slanted functional color tone, a uniformly mixed material is mechanically controlled and ejected, and a technology for optimizing it for a model to be molded is provided.

Finally, a degreasing process for removing organic matter without cracking or peeling from a zirconia ceramic structure having a gradient function type color change, and a technology for obtaining high light transmittance and strength are provided.

Furthermore, by controlling the thickness and time when photocuring a slurry whose color tone changes to a gradient function type, it is possible to produce a complex shape with 3D printing that is precise and has a strong interlayer bond despite a change in composition, so that the color can be customized In addition to artificial teeth, it is possible to manufacture a slanted functional structure based on zirconia material having various composition changes, which can be applied to the art field beyond overall industry and engineering, and can imitate the required color tone as much as possible. provide the skills

In order to solve the above problems, as a mixture of two or more slurry compositions comprising zirconia powder, a photocurable monomer, a diluent and a dispersant, the two or more slurry compositions have different colors, and the ratio of the viscosity to the shear rate 1/s is A multi-color photocurable slurry mixture of 1:3 to 3:1 is provided.

And, according to the present invention, there is provided a gradient functional ceramic structure using the above-described multi-color photo-curable slurry mixture.

In addition, according to the present invention, the step of mixing in the material mixing unit two or more multi-color photocurable slurry mixtures according to claim 1, each supplied from two or more material supply units; Comprising the step of extruding the mixed composition mixed in the material mixing unit at the discharge unit moving in the direction perpendicular to the movement direction of the blade to manufacture a ceramic structure, wherein the two or more slurry compositions are mixed in a programmed content, inclined A method of manufacturing a functional ceramic structure is provided.

According to an embodiment of the present invention, the composition of the photocurable monomers, dispersants, diluents and photocurable initiators having different physical properties is set, and the rheological behavior of the slurry compositions having different colors is optimized and mixed. It is possible to produce a multi-color photo-curable slurry mixture that has high light transmittance and strength due to the high content of zirconia powder and at the same time does not cause delamination in the 3D printing process even when the color gradient changes in color.

According to the 3D printing technology using the photocurable high content zirconia slurry having multiple color tones according to an embodiment, it is possible to manufacture a personalized inclined functional ceramic structure using a three-dimensionally designed model of a complex shape, and the required natural teeth By imitation of the color tone of the slanted functional type, it is possible to create a customized artificial tooth by adjusting the color ratio. In addition, the stacking height of the ceramic structure can be adjusted by adjusting the photocuring ability according to the difference in color tone, and the 3D resolution can be adjusted accordingly.

According to the manufacturing technology of the zirconia slurry-based structure having a gradient functional color tone using the 3D printing technology according to an embodiment, an additional part is attached in the step of extruding the slurry to the printer platform in addition to the existing slurry application method using a doctor blade The application of the slurry is automated by optimizing it to the size of a 3D drawing, providing a structure advantageous for automating the printing process, and providing a printing process that minimizes material waste.

In addition, by adjusting the color change during lamination by the mechanically operated discharge part, it is possible to automatically and uniformly mix the zirconia slurry of different colors by adjusting the extrusion ratio, giving a gradient function type color change according to the lamination. It is possible to manufacture artificial teeth having esthetics similar to natural teeth.

According to the photocurable high content zirconia 3D printing technology having a gradient functional color tone according to an embodiment, it is possible to secure improved esthetics by having a color more similar to natural teeth in the existing single-color zirconia artificial tooth manufacturing method, and 3D printing It is possible to build a process that can minimize material waste in the extrusion step of

In addition, it is possible to provide color-customized artificial teeth to individuals by adjusting the 3D drawing and the rate of color change, and it can be used in various arts and industrial fields.

1 is a graph showing the results of measuring the rheological behavior of an exemplary slurry composition.
2 is a schematic diagram showing a multi-material mixing system and a layer forming technology for 3D printing.
3 is a view showing an example of film formation according to the slurry extrusion length and the application area.
4 to 6 exemplarily show the design and movement path of the discharge unit connected to the doctor blade.
7 exemplarily shows a process in which the slurry mixture according to the present invention is extruded.
8 is a view showing a gradient functional ceramic structure manufactured using the slurry mixture according to the present invention.
9 to 11 are views showing micrographs and light transmittance graphs of the surface and fracture surfaces of the ceramic structures.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

The present invention is a mixture of two or more slurry compositions comprising zirconia powder, a photocurable monomer, a diluent and a dispersant, wherein the two or more slurry compositions have different colors, and the ratio of viscosity to shear rate 1/s is 1:3 to A 3:1, multi-color photocurable slurry mixture is provided. Specifically, the ratio of the viscosity to the shear rate 1/s may be 1.5:3 to 3:1.5, 1:2.5 to 2.5:1, 1:2 to 2:1, or 1:1.

Two or more slurry compositions satisfying the ratio of viscosity to shear rate within the above range can be mixed more easily and uniformly when mixed. This has a great advantage in the fabrication of the inclined functional structure to be described later.

The zirconia powder (or ceramic powder) may include yttria-stabilized zirconia, which has high strength and high permeability, and at the same time, bioevolutionary yttria-stabilized zirconia and an additive exhibiting color. The additive contains, for example, a large amount of Fe ₂ O ₃ , Er ₂ O ₃ , Co ₃ O ₄ and the like, and exhibits various colors such as yellow, pink, and gray. Accordingly, the zirconia powder may be a pigment powder exhibiting various colors depending on the content ratio of the additive. The two or more slurry compositions may include two or more zirconia powders exhibiting the various colors in different amounts, and may have different colors.

The zirconia powder is 10 to 80% by volume, 10 to 70% by volume, 10 to 60% by volume, 15 to 80% by volume, 15 to 70% by volume, 15 to 60% by volume, 20 to 80% by volume relative to the total ceramic composition, It may be included in an amount of 20 to 75% by volume or 20 to 60% by volume.

Two or more slurry compositions satisfying the above specific ratio of viscosity to shear rate exhibit similar or identical rheological behavior and light transmittance.

For example, adjusting the ratio of the viscosity to the specific shear rate in the above range can be achieved by appropriately selecting the type and content of the material in the slurry composition to be described below.

The photocurable monomer may be, for example, an acrylate-based monomer having two or more functional groups, for example, 1,6 Hexanediol diacrylate (HDDA), Triethylene glycol dimethacrylate (TEGDMA), Trimethylolpropane triacrylate (TMPTA), and urethane dimethacrylate. (UDMA) may be at least one selected from the group consisting of.

The content of the photocurable monomer may be 1 to 99% by weight of the total slurry composition. Specifically, the content of the photocurable monomer is 1-95% by weight, 1-90% by weight, 1-85% by weight, 1-80% by weight, 5 to 95% by weight, 5 to 90% by weight relative to the total slurry composition, 5 to 85% by weight, 10 to 95% by weight, 10 to 90% by weight, 10 to 85% by weight or 10 to 80% by weight. The content of the photocurable monomer may be appropriately selected within the above range depending on the rheological behavior of the slurry, photocurability, development reproducibility, physical properties of the ceramic structure, compatibility with other materials, and ambient environment such as test temperature.

The diluent may be at least one selected from the group consisting of Decahydronaphthalene (DECALIN) and 1,7,7-Trimethylbicyclo[2.2.1]heptan-2-one (Camphor). In addition, the diluent may be an acrylate-based monomer having one functional group, for example, isodecyl acrylate (IDA) or isobornyl acrylate (IBA). Since the acrylate-based monomer having one functional group may not have sufficient strength when used alone, it can serve as a diluent to lower the viscosity of the slurry by mixing it with the acrylate-based monomer having two or more functional groups.

The content of the diluent is 0 to 80% by weight, 0.1 to 80% by weight, 0.01 to 80% by weight, 0.001 to 80% by weight, 0.5 to 80% by weight, 0.05 to 80% by weight, 0.005 to 80% by weight relative to the photocurable monomer , 0.1 to 70% by weight, 0.01 to 70% by weight, 0.1 to 65% by weight, 0.01 to 65% by weight or 0.1 to 60% by weight. The content of the diluent may be appropriately selected within the above range depending on the rheological behavior of the slurry, photocurability, development reproducibility, physical properties of the ceramic structure, compatibility with other materials, and ambient environment such as test temperature.

As an example, the weight ratio of the photocurable monomer and the diluent may be 6:4 to 9:1. Specifically, the weight ratio of the photocurable monomer and the diluent may be 6:4 to 9:1, 6.5:3.5 to 9:1, 6:4 to 8:2, or 6.5:3.5 to 7.5:2.5.

In one embodiment, the dispersant is at least one selected from the group consisting of CC-9, KD-4, BYK-111, BYK-163, BYK-180, BYK-2001, BYK-2013 and Anti-Terra-U. can

More specifically, in the dispersant, CC-9 is VARIQUAT's polypropylene oxide quaternary ammonium chloride, and KD-4 is Croda's 12-Hydroxy octadecanoic acid homopolymer octadecanoate (CAS: 58128-22-6) Anti-Terra-U contains acidic polyester-based polymers, BYK-111 contains copolymers containing acidic groups, and BYK-163, BYK-190, BYK-2012 and BYK-2013 contain pigment affinity groups. BYK-180 includes an alkylol ammonium salt of a copolymer containing an acidic group, and BYK-2001 includes an acrylate block copolymer.

The content of the dispersant may be 0.005 to 15% by weight relative to the zirconia powder. Specifically, the content of the dispersant is 0.05 to 15% by weight, 0.5 to 15% by weight, 0.005 to 10% by weight, 0.05 to 10% by weight, 0.5 to 10% by weight, 1 to 15% by weight, 1 to 10 compared to the zirconia powder It may be included in weight %, 1 to 5 weight%, or 1 to 2 weight%. The content of the dispersant may be appropriately selected within the above range according to the pre-rheological behavior of the slurry, the degree of dispersion of the powder, the type of powder, and compatibility with monomers and diluents.

As an example, the slurry composition may further include a photocurable initiator. The photocurable initiator is not particularly limited as long as it is an initiator that is cured by irradiating light. For example, the photocurable initiator may be Phenylbis(2,4,6-trimethyl benzoylphosphine oxide) (PPO), lrgacure-819, or 2,4,6-Trimethylbenzoyldiphenylphosphine oxide (TPO).

Specifically, the photocurable initiator may be included in an amount of 0.005 wt% to 8 wt% based on the photocurable monomer. More specifically, the photocurable initiator is included in an amount of 0.05 wt% to 8 wt%, 0.5 to 8 wt%, 0.01 to 8 wt%, 0.1 to 8 wt%, or 1 wt% to 5 wt% based on the photocurable monomer can do. The content of the photocurable initiator may be appropriately selected within the above range according to the wavelength or intensity of light, or compatibility of other materials.

In addition, the present invention relates to a gradient functional ceramic structure using the above-described multi-color photo-curable slurry mixture.

In the present invention, the "ceramic structure" may be a result manufactured by 3D printing, and the "sloping functional ceramic structure" is a structure in which the type and content of main components constituting the ceramic structure are continuously changed based on one direction of the ceramic structure. It means forming a sloped structure. Here, the one direction may refer to the stacking direction (Z direction) of the manufacturing of the ceramic structure (at the time of 3D printing), that is, the height direction.

In particular, the ceramic structure according to the present invention can implement a complex shape such as a screw or tooth as well as a simple structure as a printing result, and light scattering does not occur. In addition, since the strength of the ceramic structure is high after light curing, it does not break during operation, and it has excellent processing possibilities to the extent that the shape and surface can be modified with a dental grinding machine, etc.

For example, the ceramic structure according to the present invention may have a transmittance of 1% to 45% in a visible light region. Specifically, 1 to 40%, 1 to 35%, 10 to 45%, 10 to 40%, 10 to 35%, 20 to 45%, 20 to 40%, 20 to 35%, 20 to 30 of the ceramic structure %, 20 to 25%, 30 to 40%, or 30 to 35%. In general, when a ceramic structure is manufactured by a pressing process, light transmittance of about 45% is shown. However, when a ceramic structure is manufactured by 3D printing, there is a high possibility that the transmittance is disturbed by the interface by laminating a ceramic film. Although there is a high possibility of negatively affecting the transmittance of the light transmittance, the ceramic structure according to the present invention is laminated with a ceramic film having a high light transmittance by setting photocuring conditions to prevent interference due to an interface to the structure to have the above light transmittance.

In addition, the present invention relates to a method of manufacturing the above-described inclined functional ceramic structure. The method relates to a method of manufacturing a ceramic structure using a 3D printer according to programming in which all processes from extrusion-coating-photocuring are linked.

2 is a schematic diagram showing a multi-material mixing system and a layer forming technology for 3D printing. 3 is a view showing an example of film formation according to the slurry extrusion length and the application area. 4 to 6 exemplarily show the design and movement path of the discharge unit connected to the doctor blade. 7 exemplarily shows a process in which the slurry mixture according to the present invention is extruded.

Referring to FIG. 2 , the present invention uses a multi-material mixing system together with a 3D printer in order to manufacture a tiltable ceramic structure. The multi-material mixing system may include two or more material supply units, a material mixing unit connected to the material supply unit, and a discharge unit connected to the material mixing unit.

The discharge unit moves at a speed optimized for printing using a stepping motor and extrudes a specified volume. Specifically, the discharge unit includes a static mixer, and as the ratio is adjusted to the inclined function type when extruding through the static mixer, the color of the thin film applied with the doctor blade is changed to the inclined function type.

In particular, in the present invention, the discharge part is designed to move in a direction perpendicular to the movement direction (X direction) and vertical direction (Y direction) of the doctor blade while it is coupled to at least a partial region of the doctor blade.

A doctor blade used for top-down tape-casting is usually connected to a support and moves in the X-axis direction. The reason why the optimized discharge length and area in the Y-axis are required for top-down 3D printing is shown in FIG. 3 . Referring to FIG. 3, if it cannot be extruded to the required width as shown in (A), it is necessary to extrude and apply to an area larger than the minimum sample size that can be photocured to the desired size. There is a lot of wasted amount, so an economical advantage is lowered, so a method of optimizing extrusion is required.

4 to 7 , the discharge unit is connected to the doctor blade through an 'attachment', and the discharge amount (extrusion amount) can be adjusted through a static mixer. The discharge part designed as above is introduced with a new axis for the movement direction of the blade, allowing model-customized extrusion and application from small to large areas, and it is possible to minimize the amount of slurry used through model-customized extrusion. In this way the efficiency of the printer can be increased.

The manufacturing method comprises the steps of: mixing in a material mixing unit two or more multi-color photocurable slurry mixtures according to claim 1, each supplied from two or more material supply units; and extruding the mixed composition mixed in the material mixing unit at a discharge unit moving in a direction perpendicular to the moving direction of the blade to manufacture a ceramic structure. Then, the two or more slurry compositions are mixed in a programmed amount.

Specifically, the amount of the multi-color photo-curable slurry mixture supplied to the material mixing unit may be controlled through the control of the conveying system through the pressure of compressed air or the motor according to a pre-programmed setting. In the material mixing unit, since two or more multi-color photocurable slurry mixtures are mixed, a ceramic structure having a gradient function can be manufactured from one ceramic structure according to the mixing ratio.

As an example, the multi-color photo-curable slurry mixture stored in the material supply unit may be a mixture of two or more slurry compositions with a programmed material type and content. In the slurry composition, the material type and content are selected according to a pre-designed programming, and as the ratio of the shear rate to the viscosity satisfies the above-mentioned range, the slurry composition exhibits similar rheological behavior to facilitate mixing and excellent dispersion.

On the other hand, the slurry composition comprises the steps of calcining the zirconia powder and pulverizing it using a ball mill; preparing a mixture by mixing a photocurable monomer, a diluent and a dispersant; and dispersing the zirconia powder that has undergone the grinding step in the mixture.

As an example, the pulverizing may be performed by calcining at a temperature of 800 to 1000° C. for 1 to 5 hours. Specifically, the pulverizing step is performed at a temperature of 800 to 950 ° C., 800 to 900 ° C., 850 to 1000 ° C. or 850 to 950 ° C. for 1 to 4 hours, 1 to 3 hours, 2 to 5 hours, or 2 to 4 hours. It can be carried out by calcination.

In addition, in the pulverizing step, the calcined zirconia powder may be mixed with 8 to 10 mm zirconia balls and ball milled using a ball mill for 24 hours or more. Specifically, in the pulverizing step, the calcined zirconia powder may be mixed with the zirconia balls and proceeded for at least 24 hours or at most 1 week, but 24 to 50 hours, 24 to 40 hours, or 24 to 30 hours It can be ball milled using a ball mill for a period of time.

The zirconia powder that has undergone the pulverization step as described above can be used for 3D printing because the binder is removed from the surface, there is no problem such as light reflection, and it has excellent dispersibility with the photocurable monomer.

In one embodiment, the manufacturing of the ceramic structure may include: applying the mixed composition with a blade to a thickness of 10 to 500 μm or less; forming a ceramic film by photo-curing the applied mixed composition by irradiating light; forming a ceramic compact by repeatedly performing the steps of applying with the blade and forming a ceramic film; and heat-treating the ceramic compact to prepare a ceramic structure.

For example, in the step of applying with the blade, the shape of the slurry composition applied with the blade changes depending on the shape in which the slurry composition is injected based on the blade length direction, but the standard deviation of the thickness of the applied slurry composition is 10% or less. can Specifically, the standard deviation of the thickness of the applied slurry composition may be 9% or less or 8% or less. As described above, in the method for manufacturing a ceramic structure according to the present invention, a thin film of 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, or 50 μm or less can be uniformly formed through a blade.

As an example, forming the ceramic film may be performed by irradiating light of 360 nm to 450 nm for 2 seconds to 60 seconds. Specifically, the step of forming the ceramic film is photocured by irradiating 360 nm to 450 nm light for 2 seconds to 50 seconds, 2 seconds to 40 seconds, 5 seconds to 60 seconds, 5 seconds to 50 seconds, or 5 seconds to 40 seconds. can be performed.

As an example, the heat treatment may include a first heat treatment step of degreasing the ceramic compact by increasing the temperature step by step within 1100° C.; and a second heat treatment step of sintering the ceramic compact at a temperature within a range of 1000 to 2000°C. In the first heat treatment step, the zirconia powder is stably degreased within 1100° C., and the temperature is raised step by step so that each monomer and dispersant can be removed within a range that does not break the ceramic compact while melting and vaporizing. conditions can be applied.

In addition, the second heat treatment step is specifically, 1000 ° C to 2000 ° C, 1000 ° C to 1800 ° C, 1000 ° C to 1600 ° C, 1300 ° C to 2000 ° C, 1300 ° C to 1800 ° C or 1300 ° C to a temperature of 1600 ° C. can be sintered. When the ceramic structure is heat-treated at the same temperature as described above, grain coarsening occurs during sintering, so that the ceramic structure can be highly densified without defects or pores. Accordingly, when the ceramic structure is used as an artificial tooth (eg, an implant), there is an advantage that a separate surface treatment is not required.

In addition, the forming of the ceramic ceramic structure may be performed by a tape-casting method. The tape-casting method injects a slurry composition having an appropriate viscosity, forms a thin film using a doctor blade, and forms a shape by irradiating a light source on the film. manufacturing technology. By manufacturing the ceramic structure using the taping method, it is possible to precisely manufacture a ceramic structure having a complex structure such as a tooth, and it is possible to remarkably reduce the amount of ceramic cut to manufacture an artificial tooth.

The method may further include washing the solvent between the step of forming the ceramic compact and the step of preparing the ceramic structure. The solvent may be ethanol, methanol, isopropanol, acetone or water.

Hereinafter, the present invention will be described in more detail by way of Examples and the like according to the present invention, but the scope of the present invention is not limited by the Examples presented below.

Example

With a composition according to Table 1 below, slurry compositions (A1, A2, A3) were prepared.

50% by volume
ceramic content photocurable monomer diluent zirconia powder dispersant photocuring initiator HDDA Decalin W Y P G BYK-180 TPO Density (g/cm ³ ) 1.076 0.986 6.07 6.07 6.33 6.08 1.075 1.136 Weight
(g) A1 21 9 154.1 54.1 3.9 0 4.242 0.42 A2 21 9 131.0 74.2 6.9 0 4.242 0.42 A3 21 9 125.0 80.0 7.8 0 4.248 0.42 - HDDA: 1,6 Hexanediol diacrylate (SARTOMER, Japan)
- DECALIN : Decahydronaphthalene, mixture of cis + trans reagent grade, 98%, Sigma Aldrich (Sigma Aldrich, Germany)
- W: Zirconia (Zpex 4) (Tosoh, Japan)
- Y : Zirconia (Zpex 4 - Yellow) (Tosoh, Japan)
- P : Zirconia (Zpex - Pink) (Tosoh, Japan)
- G : Zirconia (Zpex - Gray) (Tosoh, Japan)
- BYK-180 : (DISPERBYK - 180) (BYK inc., USA)
- TPO: 2,4,6-Trimethylbenzoyldiphenylphosphine oxide (Sigma Aldrich, Germany)

The prepared slurry composition was injected into a 3D printer to prepare a ceramic structure through a tape-casting method. Specifically, since the doctor blade (Dr. At this time, as shown in FIGS. 3 and 4 , the discharge unit was designed to move in a direction perpendicular to the movement direction of the doctor blade, and to adjust the amount of compression by using a static mixer. Then, the slurry was applied to a thickness of about 10 to 500 μm and then cured by irradiating light according to a cross-sectional model of a previously designed 3D model. Thereafter, all axes except the Z axis returned to the origin, and then the same sequence was repeated to form the inclined functional ceramic structure as shown in FIG. 8 .

In addition, for stable binder degreasing of the ceramic structure after photo-curing, heat treatment was performed within 1,100° C., so that each monomer and dispersant were melted and vaporized and removed within a range that did not break the ceramic structure. , and at the same time, the final temperature was 1,500 °C and sintering conditions were applied for 2 hours.

Experimental Example 1- Rheological behavior evaluation

As a result of evaluating the rheological behavior of the slurry compositions (A1, A2, A3) prepared in the Experimental Example, the results were as shown in FIG. 1 . It was confirmed that the rheological behaviors of the slurry compositions A1, A2, and A3 were similar or identical, suggesting that they could be mixed more easily and uniformly in the mixing process for gradient functional printing.

Experimental Example 2 Evaluation of photocurability

In order to confirm the curing thickness of the appropriate slurry composition when forming the ceramic structure according to the present invention, the slurry composition prepared in Example was applied by a tape-casting method using a 3D printer and irradiated with light at a wavelength of 405 nm according to the light irradiation time. The cured thickness was measured, and the results are shown in Table 2.

Zirconia Slurry Cure Thickness Test according to Curing Time layer thickness [μm] 5s 10s 15s 20s 30s 40s 50s 60s A1 60 60 70 80 90 100 110 120 A2 50 60 70 80 90 100 110 110 A3 50 60 70 80 90 100 100 110

From the results in Table 2, it can be confirmed that there is no significant difference in photocurability for each color slurries, and therefore, it is possible to simultaneously extrude them and laminate them for an inclined function.

Experimental Example 3- Analysis of physical properties of heat-treated ceramic structures

(1) Microstructure analysis of ceramic structures

In order to analyze the microstructure of the ceramic structure according to the present invention, the ceramic structure and its cut surface were observed by an experimental method based on ISO 13356-4.3.3 and ASTM E112 wire cutting method for the ceramic structure prepared in Examples, The results are shown in FIGS. 9 and 10 .

From the results of FIGS. 9 and 10 , it was confirmed that grain coarsening occurred in the ceramic powder with an average particle size of about 0.64 μm after the final heat treatment. It was confirmed that high densification was induced without defects or pores.

(2) Transmittance analysis of ceramic structures

Transmittance was analyzed in the visible light region (390 nm to 740 nm) by an experimental method based on ISO 9050, and the results are shown in FIG. 11 .

From the results of FIG. 11 , it was confirmed that complex results with different transmittances according to wavelength bands were obtained, and an average transmittance of 20 to 25% was exhibited in each color and inclined functional ceramic structure.

As described above, although the present application has been described with reference to limited embodiments and drawings, the present application is not limited thereto, and various modifications and variations may be possible.

Claims (11)

A mixture of two or more slurry compositions comprising zirconia powder, a photocurable monomer, a diluent and a dispersant,
The at least two slurry compositions have different colors, and the ratio of the viscosity to the shear rate of 1/s is 1:3 to 3:1, the multi-color photocurable slurry mixture. The multicolor photocurable slurry mixture according to claim 1, wherein the weight ratio of the photocurable monomer and the diluent is 6:4 to 9:1. The multi-color photo-curable slurry mixture according to claim 1, wherein the content of the dispersant is 0.005 to 15 wt% based on the zirconia powder. The method of claim 1, wherein the slurry composition further comprises a photocurable initiator,
The content of the photocurable initiator is 0.005 to 8% by weight based on the photocurable monomer, the multi-color photocurable slurry mixture. A gradient functional ceramic structure using the multi-color photocurable slurry mixture according to claim 1 . According to claim 5, The transmittance of the visible light region of the ceramic structure is within the range of 1% to 45%, the inclined functional ceramic structure. Mixing the multi-color photocurable slurry mixture according to claim 1, each supplied from two or more material supply units, in a material mixing unit;
Extruding the mixed composition mixed in the material mixing unit at the discharge unit moving in the direction perpendicular to the moving direction of the blade to manufacture a ceramic structure,
Wherein the two or more slurry compositions are mixed in a programmed amount, a method for producing a gradient functional ceramic structure. [Claim 8] The method of claim 7, wherein in the multi-color photo-curable slurry mixture stored in the material supply unit, two or more slurry compositions are mixed with a programmed material type and content. The method of claim 7, wherein the manufacturing of the ceramic structure comprises:
applying the mixed composition with a blade to a thickness of 10 to 500 μm or less;
forming a ceramic film by photo-curing the applied mixed composition by irradiating light;
forming a ceramic compact by repeatedly performing the steps of applying with the blade and forming a ceramic film; and
Including the step of manufacturing a ceramic structure by heat-treating the ceramic compact, a method of manufacturing a slanted functional ceramic structure. The method according to claim 9, wherein the heat treatment comprises: a first heat treatment step of degreasing the ceramic compact by increasing the temperature step by step within 1100°C; and
A method of manufacturing a gradient functional ceramic structure, comprising a second heat treatment step of sintering the ceramic compact at a temperature within a range of 1000 to 2000°C. The method of claim 9 , wherein the forming of the ceramic compact uses a tape-casting method.

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