KR20240063278A - Camphene/mixture of monomers solution based photopolymerization-assisted ceramic 3D printing technique for the control of microscale porous structures and manufactured structures - Google Patents

Abstract

The present invention is based on 3D printing technology and provides a multi-scale three-dimensional porous support capable of controlling arbitrary pore structures of hundreds of ㎛ or more, connected dendritic pore structures of several to tens of ㎛, and pore structures of tens to hundreds of nm. It is about manufacturing method.
In the present invention, a slurry composition is prepared by appropriately mixing campine, a pore-forming agent, and monomers that dissolve well at room temperature and monomers that do not dissolve well, and even if the campine content is adjusted to control microscale porosity, campine is produced under constant temperature conditions. A slurry composition capable of phase separation can be provided.

Description

Camphene/mixture of monomers solution based photopolymerization-assisted ceramic 3D printing technique for the control of microscale porous structures and manufactured structures }

The present invention relates to a campine/photopolymer solution-based photocuring porous ceramic 3D printing technology for micro-pore control.

The development of 3D printing technology allows for a variety of personalized manufacturing processes. Among them, ceramics have relatively high chemical stability and a high melting point, so it is difficult to apply them directly to 3D printing technology, so various methods to circumvent them have been developed. For molding in the form of ceramic powder, the ceramic powder can be dispersed in other materials, heat treated after the molding process to remove other materials, and then subjected to a sintering process for densification to produce a ceramic support.

The interconnected pore structure is applied to various fields such as energy, chemistry, and bio. The freeze casting method, which is one of the methods for forming a pore structure, uses freezing media that are removed after the molding process to form crystal-shaped pores. These include water, tert-butyl alcohol, and camphine. A slurry containing dispersed ceramic powder is prepared at a temperature above the melting point, cooled in a mold to form solid crystals, and the freezing medium is removed through phase separation. This forms pores. In particular, cam pins can form dendritic crystals to create interconnected pores, and can be removed as they maintain their solid shape even at room temperature and pressure.

In the freeze casting method, the melting and freezing temperature along with the crystal shape are specified depending on the material used, so in the case of cam pin, a temperature condition of about 50℃ or higher is required before the molding step.

Ceramic 3D printing using photocuring is a method of stacking ceramic slurry one layer at a time and photopolymer photopolymer by irradiating light that cuts the three-dimensional design into two dimensions according to the height. Representative methods include stereolithography (SL) using a laser and There is a DMD chip-based digital light processing (DLP) method. Among these, the DLP method can achieve excellent resolution and fast printing speed by curing one layer at a time.

In the past, there were reports overseas on porous ceramic manufacturing technology using a campine/photopolymer-based mold. However, since the temperature must be maintained above the melting point of campine during slurry production, there were problems such as reduced energy efficiency and evaporation of campine between processes (Non-patent Document 1).

To solve this problem, the present invention developed a Campin/photopolymer solution-based ceramic slurry composition using a photopolymer that melts Campin at room temperature, and a 3D printing technology using the same. The above technology overcomes the limitations of cam pin's freezing point (melting point) above room temperature and manufactures porous ceramic through thermally induced phase separation by lowering the temperature of the slurry to below the phase separation temperature during the printing process (Non-patent Document 2).

However, in the above technology, the amount of campin that can be melted at room temperature is determined depending on the photopolymer material, and the phase separation temperature changes depending on the campin content, so the campin-induced microscale pore structure can be controlled by adjusting the campin content (porosity, pore size, etc.) There were limitations in shape, etc.).

1. Journal of the American Ceramic Society, 95(12), 3763-3768 2. Journal of the European Ceramic Society, 41(1), 655-662,

The present invention is based on a campine/photopolymer solution using two photopolymers with different campine solubilities, and is a photocurable ceramic slurry that can have a constant phase separation temperature even when the campine content changes by adjusting the ratio between the two photopolymers even in a given material. The purpose is to provide a composition.

The present invention includes the steps of mixing campine and photopolymer at 20 to 30°C to prepare a campine/photopolymer solution; and

Comprising the step of mixing the campine/photopolymer solution, ceramic powder, dispersant, and photocuring initiator to prepare a photocurable ceramic slurry composition,

The photopolymer includes triethylene glycol dimethacrylate (TEGDMA) and polyethylene glycol diacrylate (PEGDA),

A method for producing a photocurable ceramic slurry composition is provided, wherein the crystallization temperature of cam pin in the photocurable ceramic slurry composition is 5 to 15°C.

In addition, the present invention is manufactured by the above-described manufacturing method,

Contains campine, photopolymer, ceramic powder, dispersant and photocuring initiator,

Provided is a photocurable ceramic slurry composition in which campin exists in a liquid state in the composition at 20 to 30°C, and the crystallization temperature of the campin is 5 to 15°C.

In addition, the present invention includes forming a ceramic slurry layer for 3D printing by applying a photocurable ceramic slurry composition to a 3D printing bed;

After inducing solidification of the cam pin, forming a ceramic structure by photocuring it into a pre-designed shape;

Forming a porous ceramic structure with micropores by freeze-drying the ceramic structure; and

It includes heat treating the porous ceramic structure at a high temperature,

The temperature of the 3D printing bed is -20 to 15°C.

A method for manufacturing a three-dimensional porous support having a three-dimensionally connected micro-pore structure is provided.

In the present invention, by applying a mixture of photopolymers with different solubilities for campin, it is possible to set a constant phase separation temperature even by adjusting the campine content regardless of the melting point of campin, thereby creating porosity with a controlled micropore structure under specific printing temperature conditions. Ceramic printing can be performed.

The photocurable ceramic slurry composition according to the present invention can be freely set at the phase separation temperature of the cam pin for forming porosity and the printing temperature for this, and can be manufactured at room temperature without separate heating. In addition, for various slurry compositions in which the campine content is adjusted to control porosity, the phase separation temperature for porosity formation can be set individually, allowing printing under the same printing temperature conditions. In addition, the slurry composition with various campine contents can be manufactured at room temperature without separate heating, and the phase separation temperature can be set relatively close to room temperature, making it energy efficient and solving the problem of existing moisture adsorption.

In addition, the slurry composition according to the present invention has cam pins phase separated on a temperature-controlled printing bed and becomes a semi-solid state, so it prevents collapse during laminated manufacturing of a structure with an overhang angle above a certain level in 3D printing technology. There is no need for a printing supporter for this purpose.

The three-dimensional porous support manufactured by the present invention has a controlled micropore structure and can have a three-dimensional complex shape. Specifically, it has a pore structure of more than 100 ㎛ through 3D printing and a pore structure of several to several tens of ㎛ induced by cam pin, and the degree of densification (spacing) of the ceramic powder by controlling the sintering conditions is adjusted to tens to hundreds of nm. It can be used in a variety of areas such as bio and energy fields, such as bone substitutes, as it can control pores or surfaces at any level.

Figure 1 shows the dissolution pattern of campine in each photopolymer at room temperature.
Figure 2 shows the phase equilibrium diagram of Campine/TEGDMA/PEGDA at room temperature.
Figure 3 shows the DSC measurement results for each composition in which the camphine content and the content of each photopolymer were adjusted.
Figure 4 shows a schematic diagram of porous ceramic 3D printing using the DLP method.
Figure 5 shows changes in the state of slurry according to the manufacturing process.
Figure 6 shows TGA measurement results for each composition in the examples.
Figure 7 shows porous ceramic structures according to composition in Examples.
Figure 8 shows SEM photographs of the internal microstructure of porous ceramic structures for each composition in Examples.
Figure 9 shows SEM photographs of the external microstructure of porous ceramic structures for each composition in Examples.
Figure 10 shows porous supports according to composition in Examples.
Figure 11 shows SEM photographs (sintered at 1550°C) of the internal microstructure of porous supports for each composition in Examples.
Figure 12 shows micro-CT images of porous supports for each composition in Examples.
Figure 13 shows the ceramic microstructure according to the final heat treatment temperature (1350, 1450, 1550°C) conditions of Example 3-3.

The present invention includes the steps of mixing campine and photopolymer at 20 to 30°C to prepare a campine/photopolymer solution; and

It relates to a method for producing a photocurable ceramic slurry composition, including the step of preparing a photocurable ceramic slurry composition by mixing the campine/photopolymer solution, ceramic powder, dispersant, and photocuring initiator.

Existing methods for manufacturing porous ceramics using cam pins using freeze casting methods involve continuously applying heat to melt solid cam pins at room temperature to produce a slurry in which ceramic powder is evenly dispersed while maintaining the liquid state, and fixing the shape using a mold, etc. After that, the camphin was solidified. As a result, it consumed a lot of energy and required separate equipment to heat and disperse the ceramic powder.

In the previous research of the inventor of the present invention, a 3D printing technology was developed to manufacture porous ceramics through thermally induced phase separation based on photopolymer that melts cam pins. However, the phase separation temperature of the campine varies depending on the type of photopolymer and the campine content, so there is a limit to controlling the campine content to control the microscale pore structure. Specifically, since the amount of campine that can be dissolved (solubility) at a specific temperature is constant, when the campine content is adjusted to control porosity, the saturation degree of campine in the slurry composition changes, and the temperature required for phase separation also changes. As a result, the temperature of the platform during 3D printing varies depending on the content of cam pin, which has the disadvantage of making printing difficult because moisture is adsorbed between layers.

Therefore, in the present invention, a photopolymer that can melt a large amount (50 parts by weight or more) of cam pin at room temperature and a photopolymer that melts a small amount (less than 50 parts by weight) or does not melt cam pin are selected, and the cam pin and the two photopolymers are well mixed. A photopolymer capable of forming a solution was selected. In addition, the phase separation point according to the component ratio was identified through a ternary phase diagram of the campine/photopolymer solution at room temperature, and a composition in which the desired amount of campine phase separated at a temperature of 5 to 15°C was selected. .

A photocurable ceramic slurry composition was prepared by mixing the selected campine/photopolymer solution with ceramic powder, dispersant, and photocuring initiator. The prepared slurry composition can be phase-separated at 5 to 15°C regardless of the campine content by adjusting the ratio of the photopolymer (ratio between the two monomers) according to the campine content.

The photocurable ceramic slurry composition was applied to a certain thickness on a temperature-controllable 3D printing bed, and phase separation (solidification) of the cam pin was induced. Next, a 3D structure was manufactured by repeating the selective curing process using 2D DLP light that sliced the 3D design shape for each layer (ceramic structure manufacturing). In the manufactured ceramic structure, microscale pores are formed by removing phase-separated solid campines through washing and freeze-drying, and at a campine content above a certain level, a three-dimensionally connected pore structure is formed (porous ceramic structure manufacturing). Next, organic compounds (materials other than ceramics) are removed through a controlled heat treatment process, and the surface of the ceramic structure or tens to hundreds of nanoscale pores between ceramic powders can be controlled through a sintering process.

As a result, in the present invention, the pore structure of 100 ㎛ or more is controlled through 3D printing of the photocurable ceramic slurry composition, the pore structure of several to tens of ㎛ is controlled by controlling the cam pin content, and the pore structure is controlled at the level of several to tens of ㎛ by controlling the heat treatment (sintering) conditions. By adjusting the degree of densification between ceramic powders, a porous support with controlled pores of tens to hundreds of nm or the surface of the ceramic structure is provided.

Hereinafter, the method for producing the photocurable ceramic slurry composition of the present invention will be described in more detail.

Slurry generally refers to a liquid state with low fluidity containing a high concentration of suspended substances. In the present invention, a composition containing campine, photopolymer, ceramic powder, dispersant, and photocuring initiator, which will be described below, can be expressed as a slurry.

The method for producing a photocurable ceramic slurry composition (hereinafter, slurry composition) according to the present invention includes the steps of (S1) mixing campine and photopolymer at 20 to 30°C to prepare a campine/photopolymer solution; and

(S2) comprising mixing the campine/photopolymer solution, ceramic powder, dispersant, and photocuring initiator to prepare a photocurable ceramic slurry composition.

First, step (S1) is a step of preparing a campine/photopolymer solution.

In the present invention, Camphene can be used as a freezing medium and a pore agent to create interconnected pores within a porous support. The cam pin is in a solid state at room temperature, but has the property of being in a liquid state at a certain temperature. Specifically, when campine is cooled from a liquid state, it forms a solid crystal and pushes out materials other than the original material, and can be removed after the molding process to form pores.

In the present invention, the cam pin may exist in a liquid state in a photocurable ceramic slurry composition at room temperature.

In the present invention, the photopolymer (photocurable monomer) can dissolve campine at room temperature. In addition, the photopolymer can play a role in uniformly forming ceramic powder and controlling the viscosity of the photocurable ceramic slurry composition and the strength of the molded body.

In the present invention, photopolymer can be used in the dictionary meaning of 'unit molecule capable of forming a polymer by irradiation of light', as well as oligomer, which is an oligomer produced by polymerizing the unit molecule to a low degree. .

This photopolymer is a mixture of a photopolymer that can dissolve a large amount (more than 50 parts by weight) of campine at room temperature and a photopolymer that can dissolve a small amount (less than 50 parts by weight) or does not melt it.

In one embodiment, a photopolymer that can dissolve a large amount of campine at room temperature and a photopolymer that melts a small amount of campine at room temperature or does not melt a small amount of campine at room temperature have miscibility and can be stably mixed, and the viscosity is sufficiently low that the campine content is low. Even if the mixing ratio is adjusted, it is possible to produce a slurry composition.

In one embodiment, the photopolymer that can dissolve a large amount of campine at room temperature is triethylene glycol dimethacrylate (TEGDMA), and the photopolymer that melts a small amount of campine or does not dissolve campine at room temperature is polyethylene glycol diacrylate. It is polyethylene glycol diacrylate (PEGDA).

In the present invention, by using a mixture of a photopolymer that can melt a large amount of campin at room temperature and a photopolymer that melts a small amount of campin or does not melt a small amount of campin at room temperature, 3D photocuring is achieved under constant temperature conditions regardless of the concentration (content) of campin. A slurry composition capable of printing can be prepared. In addition, regardless of the content of campine, the phase separation temperature of campine can be constantly controlled within the slurry composition, thereby simplifying the process.

In one embodiment, the crystallization temperature of campine in the slurry composition may be 5 to 15°C or 10 to 12°C.

In one embodiment, the content of the campine may be 10 to 60 parts by weight, or 10 to 40 parts by weight, based on 100 parts by weight of the slurry composition, and the volume ratio is 5 to 80 vol%, 10 to 70 vol%, and 20 to 60 parts by weight. It may be vol% or 20 to 50 vol%. Additionally, the content of the photopolymer may be 5 to 40 parts by weight, or 10 to 25 parts by weight, based on 100 parts by weight of the slurry composition.

In one embodiment, the weight ratio of campine and photopolymer may be 2:8 to 7:3 or 3:7 to 7:3. In the above range, phase separation between campin and photopolymer does not occur, and campin can be maximally dissolved in the photopolymer at room temperature. If too little of the photocurable monomer that acts as a binder is used or too much cam pin is used, the porosity will increase and the strength of the support will be weak, which may cause it to break easily. If too much of the photocurable monomer is used, the support may be easily broken. Since there are concerns that it may be difficult to implement pores, it is recommended to adjust it to the above range.

In one embodiment, the weight ratio of the photopolymer that can dissolve a large amount of campin at room temperature and the photopolymer that melts a small amount of campin or does not melt campin at room temperature may be 2:8 to 9:1 or 4:6 to 9:1. .

In one embodiment, in step (S1), campine and photopolymer are mixed to prepare a campine/photopolymer solution, and this step may be performed at 20 to 30° C. or room temperature.

In the present invention, step (S2) is a step of mixing the campine/photopolymer solution prepared in step (S1), ceramic powder, dispersant, and photocuring initiator. A photocurable ceramic slurry composition can be prepared through the above steps.

In the present invention, the slurry composition can improve the physical properties of ceramic structures and supports by including ceramic powder. This ceramic powder may be included in a volume of 5 to 40 vol% in the slurry composition. In the case of a slurry composition with a low content of less than 5 vol%, it is easy to manufacture, but there is a risk of quality deterioration.

In one embodiment, the type of ceramic powder is not particularly limited, and for example, Hydroxy Apatite (HA), Fluoridated Hydroxy Apatite (FHA), tricalciumphosphate (TCP), BCP ( One or more selected from the group consisting of biphasic calcium phosphate, alumina, zirconina, silica, and bioglass may be used.

In one embodiment, the average particle size of the ceramic powder is not particularly limited and may be 0.05 to 10 ㎛, specifically 0.1 to 5 ㎛, and more specifically 0.1 to 1 ㎛. Dispersion is easy within the above range.

Additionally, the content of the ceramic powder may be 10 to 70 parts by weight or 20 to 60 parts by weight based on 100 parts by weight of the slurry composition. Within the above content range, ceramic structures and supports with excellent physical properties can be manufactured.

In the present invention, the dispersant can be used to uniformly mix photopolymer, campine, and ceramic powder.

In one embodiment, the type of dispersant is not particularly limited and includes, for example, xylene, an organic material containing acetate, an alkylammonium salt copolymer compound, and a polyester/polyether-based compound. , one or more selected from the group consisting of a copolymer containing a phosphoric acid group and a copolymer having an amine group may be used.

In one embodiment, the content of the dispersant may be 1 to 10 parts by weight, 1 to 5 parts by weight, or 1 to 3 parts by weight based on 100 parts by weight of the slurry composition. A uniform slurry composition can be prepared within the above range. If the content is less than 1 part by weight, it is difficult to produce a slurry with a uniform composition due to the ceramic powder particles agglomerating with each other, and if it exceeds 10 parts by weight, there is a risk that the strength may decrease.

Additionally, in the present invention, the photocuring initiator can polymerize the photopolymer by forming free radicals using electromagnetic waves in a selectively controlled specific wavelength range.

In one embodiment, the type of photocuring initiator is not particularly limited, and for example, Phenylbis(2,4,6-trimethyl benzoylphosphine oxide), PPO ), Phenylbis(2, 4, 6-trimethyl benzoylphosphine oxide), PPO), 1-Hydroxy-cyclohexyl-phenyl-ketone (1-Hydroxy- cyclohexyl-phenyl-ketone), 2-Hydroxy-2-methyl-1-phenyl-1-propanone (2-Hydroxy-2-methyl-1-phenyl-1-propanone), 2-hydroxy-1-[ 4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone (2-Hydroxy-1-[4-(2-hydroxyethoxy) phenyl]-2-methyl-1-propanone), methylbenzoyl Formate (Methylbenzoylformate), oxy-phenyl-acetic acid -2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester (oxy-phenyl-acetic acid -2-[2 oxo-2phenyl-acetoxy- ethoxy]-ethyl ester), oxy-phenyl-acetic acid-2-[2-hydroxy-ethoxy]-ethyl ester (oxy-phenyl-acetic acid-2-[2-hydroxy-ethoxy]-ethyl ester), alpha -Dimethoxy-alpha-phenylacetophenone (alpha-dimethoxy-alpha-phenylacetophenone), 2-benzyl-2-(dimethylamino)1-[4-(4-morpholinyl) phenyl]-1-butanone (2 -Benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl) phenyl]-1-butanone), 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl) Nyl)-1-propanone (2-Methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone) and diphenyl (2,4,6-trimethylbenzoyl)-phosphenyl One or more selected from the group consisting of diphenyl (2,4,6-trimethylbenzoyl)-phosphine oxide (TPO) can be used.

In one embodiment, the content of the photocuring initiator may be 0.1 to 1 part by weight or 0.2 to 0.6 part by weight based on 100 parts by weight of the slurry composition. Additionally, the content of the photocuring initiator may be 1 to 5 parts by weight or 1 to 3 parts by weight based on 100 parts by weight of the photopolymer. Photocuring of the photopolymer can be easily performed within the above range.

In one embodiment, mixing of the above-described components in step (S2), i.e., campine/photopolymer solution, ceramic powder, dispersant, and photocuring initiator, may be performed through a general method in the art.

In one embodiment, the campine/photopolymer solution, ceramic powder, and dispersant may first be mixed, and then the photocuring initiator may be mixed. Additionally, when mixing ceramic powder, zirconia balls can be added to evenly disperse the powder.

In one embodiment, step (S2) may be performed under the temperature conditions of step (S1), that is, 20 to 30°C.

A photocurable ceramic slurry composition can be prepared through the above-described steps (S1) and (S2). The temperature of the prepared photocurable ceramic slurry composition may be 20 to 30°C.

Additionally, the present invention relates to a photocurable ceramic slurry composition prepared by the method for producing the photocurable ceramic slurry composition described above.

The photocurable ceramic slurry composition according to the present invention may include the above-described cam pin, photopolymer, ceramic powder, dispersant, and photocure initiator.

The photopolymer may be a mixture of a photopolymer that can dissolve a large amount of campin at room temperature and a photopolymer that melts a small amount of campin or does not melt campin at room temperature.

In one embodiment, the temperature of the photocurable ceramic slurry composition may be 20 to 30°C. Since the campin used in the present invention exists in a liquid state in the slurry composition of the present invention, 3D printing can be performed without being affected by temperature conditions during 3D printing.

In addition, regardless of the content of campin, the phase separation temperature of campin is maintained constant in the photocurable ceramic slurry composition, so it is not affected by temperature and humidity depending on the content of campin during 3D printing.

Additionally, the present invention relates to a method of manufacturing a ceramic structure using the photocurable ceramic slurry composition described above.

The method for manufacturing a ceramic structure of the present invention includes the steps of (A) applying a photocurable ceramic slurry composition to a 3D printing bed to form a ceramic slurry layer for 3D printing;

(B) forming a ceramic structure by inducing solidification of the cam pin and then photocuring it into a pre-designed shape;

(C) forming a porous ceramic structure with micropores by freeze-drying the ceramic structure; and

(D) heat treating the porous ceramic structure at high temperature.

In the present invention, the shape of the ceramic structure and the ceramic support can be maintained by using the photocurable ceramic slurry composition described above, and the physical properties of the ceramic support can also be adjusted.

The present invention can provide a photocurable ceramic-based 3D printing technology applicable to vapor phase 3D printers through the fusion of computer control-based 3D printing technology and photocuring molding technology.

In one embodiment, the photocurable ceramic slurry composition of the present invention applies a tape casting technique to the top-down printing method, using a thermoelectric element to form a thin layer on a printing bed that can be set to a low temperature. After forming campine crystals by stacking slurry layers, they can be printed in equipment that can be photocured using a DLP projector in the 405 nm wavelength range.

In the present invention, step (A) is a step of applying a photocurable ceramic slurry composition to form a ceramic slurry layer for 3D printing.

In the present invention, 3D printing can print 3D drawing data using a printer according to a program designed in advance on a computer.

Specifically, the photocurable ceramic slurry composition may be applied to the printing bed, and a ceramic slurry layer of a constant thickness may be formed using a doctor blade at a temperature of 20 to 30°C.

At this time, the temperature of the printing bed may be -20 to 15°C. In the above temperature range, the cam pin may be phase separated (solidified) into a solid at an appropriate rate in the photocurable ceramic slurry composition. In other words, not only slurry coating can easily occur at the above temperature, but also crystal formation of cam pin can sufficiently occur.

In particular, campin contained in the slurry composition for realizing microscale pores exists in a liquid state in the slurry composition at room temperature, so printing is possible at room temperature without setting separate temperature conditions. Through this, when separate printing bed heating is not performed during conventional 3D printing, the cam pin solidifies very quickly, thereby preventing the phenomenon of having an uneven thickness when forming a slurry layer using a doctor blade.

In one embodiment, the thickness of the ceramic slurry layer is controllable using a doctor blade and may be 25 to 200 μm.

In the present invention, step (B) is a step of inducing solidification of cam pin in the ceramic slurry layer formed in step (A) and then photocuring. In the present invention, the ceramic slurry layer can be photocured into a pre-designed shape.

In the present invention, a ceramic structure with micropores can be formed by continuously repeating the ceramic slurry layer formation/photocuring process.

In one embodiment, the solidification induction time can be adjusted depending on the content of campine in the slurry.

In one embodiment, photocuring may be performed by visible light or ultraviolet light emitted from a DLP projector in the 405 nm wavelength range. The ultraviolet irradiation may be performed using a UV beam, etc., and in this case, the intensity of the irradiated ultraviolet rays may be 1 to 300 W/m ² .

In one embodiment, the photocuring time may be determined to completely photocure one layer of the ceramic slurry. If the time is short, the bond between the ceramic forming layers may be very weak.

In addition, the photocuring time can be adjusted appropriately so that the bonding area of the layer during photocuring can be cured a little deeper than the previously programmed layer thickness in order to completely cure one layer of the ceramic slurry and bond it to the previously cured upper layer. You can. This allows the layer to be cured to overlap the upper layer.

Step (C) is the freeze-drying step, which is a step of freeze-drying to remove the freezing medium, that is, campine, to form a porous ceramic structure with three-dimensionally connected micropores.

In one embodiment, when three-dimensionally connected cam pins present in the ceramic structure are removed, micropores remain in their place.

In one embodiment, freeze-drying is performed at a temperature of -70°C to 0°C or -50°C to -10°C and a pressure of 0.1 to 20 mTorr or 1 to 10 mTorr so that the cam pin can be easily removed without damaging the ceramic structure. You can.

The term "three-dimensionally connected micropores" refers to micropores connected in multiple directions, for example, not closed pores, such as air bubbles, but located inside the specimen regardless of the top, bottom, or both sides. It refers to an open pore structure connected in multiple directions.

In the present invention, step (D) is a step of heat treating the porous ceramic structure at a high temperature. Through this step, residual polymers can be removed and the ceramic wall can be densified.

In the present invention, heat treatment may be performed at 100 to 600°C for 1 to 40 hours, followed by secondary heat treatment (sintering) at 600 to 1700°C for 1 to 10 hours.

In one embodiment, the primary heat treatment can effectively remove polymers present inside a porous ceramic structure manufactured by photocuring.

The first heat treatment may be performed at 100 to 600°C for 1 to 40 hours. If the heat treatment temperature is too low or the time is too short, there is a risk that the mechanical strength will be lowered and the polymer and/or dispersant may not be easily removed. In addition, the removal of impurities can be more easily performed by performing heat treatment while increasing the temperature step by step.

Secondary heat treatment (sintering) can densify ceramic walls and improve adhesion between ceramic walls.

The secondary heat treatment may be performed at 600 to 1700°C or 1300 to 1700°C for 1 to 10 hours. If the secondary heat treatment temperature is too high or the time is long, there is a risk that the pore structure and chemical composition of the ceramic structure may differ.

Additionally, the present invention relates to a porous support prepared by the above-described manufacturing method.

The porous support manufactured by the present invention has a controlled micropore structure and can have a three-dimensional complex shape. The porous support has a pore structure of 100 ㎛ or more through 3D printing, and a pore structure of several to tens of ㎛ induced by Campin, and also has a pore structure of several tens of ㎛ by controlling the degree of densification (spacing) of the ceramic powder through adjustment of sintering conditions. It can have pores of ~hundreds of nm.

Additionally, the present invention relates to a product comprising the porous support.

Since the porous scaffold according to the present invention has a regular pore structure and excellent mechanical properties, it can be used as a biomaterial such as an ion battery, filter, catalyst support, drug carrier, or bone substitute.

The advantages and features of the present invention and methods for achieving them will become clear with reference to the embodiments described in detail below. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms, and the present embodiments are merely intended to ensure that the disclosure of the present invention is complete and to include common knowledge in the technical field to which the present invention pertains. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

Example

Preparation Example 1. Campine/photopolymer solution preparation

A photopolymer that can melt a large amount of campin at room temperature and a photopolymer that melts a small amount of campin or does not melt campin at room temperature were selected.

Specifically, triethylene glycol dimethacrylate (TEGDMA) was selected as a photopolymer that can dissolve a large amount of campine at room temperature, and polyethylene glycol diacrylate (PEGDA) was selected as a photopolymer that does not or does not dissolve a small amount of campine. Thus, it was confirmed that they mixed well with campin.

Figure 1 is a photograph showing the campine dissolution pattern of photopolymer at room temperature. The ratio attached to the container in the drawing represents the mass ratio of camphine and TEGDMA (or PEGDA).

As shown in Figure 1, it can be seen that up to 70% by weight of campine is completely dissolved in the campine and TEGDMA solution at room temperature, and up to 10% by weight of campine is dissolved in the campine and PEGDA solution.

Preparation Example 2. Creation of Campine/TEGDMA/PEGDA ternary phase equilibrium diagram

Phase equilibrium diagrams of campine, TEGDMA, and PEGDA solutions were prepared at room temperature (25°C).

Figure 2 shows the phase equilibrium diagram of campine/TEGDMA/PEGDA at room temperature.

As shown in FIG. 2, based on the boundary where solution/campine crystals are formed, campine is melted at room temperature at the desired campine content, and the ratio between photopolymers in which campine crystals are formed when the temperature is lowered to a certain level can be confirmed.

Preparation Example 3. Setting the ratio between photopolymers according to campine content

A composition was set in which the campine content was adjusted to control the fine pore structure and the photopolymer content (ratio) was adjusted accordingly. Through this, the phase separation temperature of campin, which changes as the campine content changes, can be arbitrarily set.

Examples 1-1 to 1-3. Slurry composition preparation

Ceramic slurry for photocurable 3D printing was prepared by adding ceramic powder, a dispersant for dispersing the ceramic powder, and a photocuring initiator for photocuring initiation (radical formation) to the set campine/photopolymer solution composition (Table 1 below) ).

Example 1-1 Example 1-2 Example 1-3 Qigong Festival campine 12.5g
(30vol%) 17g
(40vol%) 21g
(50vol%) photopolymer TEGDMA 11.08g 12.82 g 13.43 g PEGDA 11.82g 6.96g 2.58g ceramic powder Al2O3 43.89 g 38.37 g 31.6 g dispersant BYK180 2.19g 1.92g 1.58g photocuring initiator TPO 0.34 g 0.4g 0.48g

Comparative Examples 1-1 to 1-3. Slurry composition preparation

A slurry composition was prepared with the composition and content shown in Table 2 below.

Comparative Example 1-1 Comparative Example 1-2 Comparative Example 1-3 Qigong Festival campine 18g 18g 21g photopolymer TEGDMA X 6g 9g HDDA 6g X X PEGDA X X X UDMA 10.7 g 10.7 g X Glycerin X X 13g ceramic powder Al2O3 59g 59g 66g dispersant BYK106 0.885 g 0.885 g 0.99 g photocuring initiator TPO 0.5g 0.5g 0.66g

The slurry composition prepared in the comparative example had problems such as no flowability due to the high viscosity of the slurry composition, insufficient strength after photocuring, or photopolymers not mixing with each other.

Specifically, in the case of compositions with relatively low campine content, the amount of low-viscosity monomers (HDDA and/or TEGDMA) that dissolve a large amount of campine must be reduced, so to this end, substances that dissolve well with campine and HDDA and/or TEGDMA are added. Should be. If non-hardening substances such as glycerin are added, there is a risk that strength will decrease after curing. In addition, when using a high viscosity material such as UDMA that is photocurable without dissolving the cam pin, the viscosity becomes very high, making it difficult to apply to 3D printing.

PEGDA has low campine solubility, mixes well with campine and TEGDMA solutions, and is a photopolymer with relatively low viscosity, so it not only solves the above problems, but also has the advantage of being able to constantly control the phase separation temperature of campine.

Experimental Example 1. Measurement of phase separation temperature of slurry composition

The phase separation temperature of the slurry composition prepared in the examples was measured.

Specifically, the phase separation temperature was measured by cooling the slurry composition at a constant rate using differential scanning calorimetry (DSC) equipment and measuring the temperature at which campine phase separates and solidifies.

Table 3 and Figure 3 below show the DSC measurement results for each slurry composition in which the campine content and photopolymer content were adjusted. In the tables and figures, 30 vol%, 40 vol% and 50 vol% refer to the slurry compositions of Examples 1-1, 1-2 and 1-3, respectively.

As shown in the table and drawings, it can be confirmed that the cam pins in the slurry compositions of Examples 1-1 to 1-3 all undergo phase separation around 10°C.

Meanwhile, Table 4 below shows the phase change temperature measurement results according to the Campine:TEGDMA ratio (mass ratio) when only TEGDMA was used as the photocurable monomer.

As shown in the table above, it can be confirmed that when only TEGDMA is used as the photopolymer, the phase change temperature of cam pin cannot be maintained constant. In addition, when the campin content is less than 50% by weight, the phase separation temperature becomes very low, making pore formation difficult and printing difficult.

When TEGDMA and PEGDA are used together as photopolymers as in the present invention, a slurry composition in which campines phase separates at around 10°C can be set. Through this, it can be confirmed that the phase separation temperature of campine, which changes as the campine content changes, can be adjusted.

Examples 2-1 to 2-3. Manufacturing of porous ceramic structures

Using the slurry compositions prepared in Examples 1-1 to 1-3, porous ceramics with a micropore structure controlled according to the campine content were manufactured using a photocuring 3D printer.

Figure 4 shows a schematic diagram of porous ceramic 3D printing using the DLP method, and a ceramic structure with a controlled micropore structure was manufactured according to the process of the schematic diagram.

In the present invention, although the campine content is adjusted for each composition, the phase separation temperature of the campine is set similarly, so that printing is possible under the same temperature conditions even if the composition changes.

Examples 3-1 to 3-3. Porous scaffold fabrication

A porous support was prepared by post-processing the porous ceramic structures prepared in Examples 2-1 to 2-3.

Figure 5 is a schematic diagram showing changes in slurry state by manufacturing process.

The manufactured ceramic structure is subjected to ethanol ultrasonic cleaning to remove surrounding unphotocured slurry. After manufacturing a porous ceramic structure with cam pins removed through room temperature/normal pressure or freeze-drying, the polymer is removed without damage by gradually setting heat treatment conditions based on the TGA measurement results, and then the porous structure is formed through a sintering process at a controlled sintering temperature. Prepare the support.

Table 5 below shows heat treatment conditions.

Experimental Example 2. TGA measurement results

The TGA of the porous ceramic structures prepared in Preparation Examples 2-1 to 2-3 was measured.

Figure 6 shows the TGA measurement results of the porous ceramic structures of Examples 2-1 to 2-3.

Through the above figure, the temperature at which organic compounds excluding ceramics in each composition are thermally decomposed and the thermal decomposition rate at each temperature can be seen. Based on this, step-by-step heat treatment conditions can be set as shown in Table 5 at each temperature point where thermal decomposition begins to occur slowly in order to remove organic compounds without damaging the structure.

Experimental Example 3. Measurement of pore structure of porous ceramic structure

In Example 2, after 3D printing and photocuring, the uncured slurry was washed, and then a freeze-drying process was performed to manufacture a porous ceramic structure with a complex pore structure of 100 um or more and a controlled micropore structure.

Figure 7 shows a photograph of the manufactured porous ceramic structure. Hereinafter, in the drawings, 30, 40, and 50 refer to the structures of Example 2-1, Example 2-2, and Example 2-3, respectively.

In this experimental example, a cylindrical structure with a hexagonal honeycomb structure was manufactured. When the campine content is above a certain level, it can be confirmed that the surface can also have connected porosity.

Additionally, Figure 8 shows an SEM image of the internal microstructure of the porous ceramic structure, and Figure 9 shows an SEM image of the external microstructure.

As shown in the figure, it can be confirmed that a dendritic fine pore structure was formed by campin, the pore structure was controlled depending on the composition, and a fine pore structure connected not only to the inside but also to the outside was formed depending on the campin content. .

Experimental Example 4. Measurement of pore structure of sintered body

In Example 3, the porous ceramic structure was heat treated to gradually remove materials other than ceramic without damage, and the ceramic powder was sintered (densified) at high temperature. By setting the sintering temperature differently, the degree of densification can be adjusted to form nanoscale pores or control the surface of the microstructure.

Ultimately, it has a complex shape (pore structure at the level of 100 ㎛ or more) and a fine pore structure (cam pin-based pore structure at the level of several to tens of ㎛, pores or microstructure at the level of tens to hundreds of nanometers by controlling the degree of densification of ceramic powder. A porous ceramic structure with a controlled surface was manufactured.

Figure 10 shows a photograph of the prepared porous support (sintered at 1550°C). Hereinafter, in the drawings, 30, 40, and 50 refer to the porous supports of Example 3-1, Example 3-2, and Example 3-3, respectively.

As shown in the figure, it can be confirmed that in each cylindrical molded body having a honeycomb structure in which the fine pore structure is controlled by controlling the campine content, organic substances other than ceramics have been removed through heat treatment, and a ceramic structure in which the powder has been densified has been manufactured. .

Additionally, Figure 11 shows an SEM image of the internal microstructure of the porous support, and Figure 12 shows a micro CT image.

As shown in the figure, it can be confirmed that the campine-based pore structure of several to tens of μm was maintained even after heat treatment, the ceramic was densified, and the support was manufactured without damage to the overall structure implemented by 3D printing.

Additionally, Figure 13 shows the ceramic microstructure according to the final heat treatment temperature (1350, 1450, 1550°C) conditions of Example 3-3.

As shown in the figure, the degree of densification (spacing) of the ceramic powder can be adjusted through heat treatment, and it can be confirmed that pores of tens to hundreds of nm are formed.

Claims (14)

Preparing a campine/photopolymer solution by mixing campine and photopolymer at 20 to 30°C; and
Comprising the step of mixing the campine/photopolymer solution, ceramic powder, dispersant, and photocuring initiator to prepare a photocurable ceramic slurry composition,
The photopolymer includes triethylene glycol dimethacrylate (TEGDMA) and polyethylene glycol diacrylate (PEGDA),
A method for producing a photocurable ceramic slurry composition, wherein the crystallization temperature of cam pin in the photocurable ceramic slurry composition is 5 to 15°C.
According to claim 1,
A method for producing a photocurable ceramic slurry composition, wherein the content of campine in the photocurable ceramic slurry composition is 5 to 80 vol%.
According to claim 1,
A method for producing a photocurable ceramic slurry composition, wherein campine and photopolymer are mixed at a weight ratio of 2:8 to 7:3.
According to claim 1,
A method for producing a photocurable ceramic slurry composition, wherein TEGDMA and PEGDA are mixed at a weight ratio of 2:8 to 9:1.
According to claim 1,
Ceramic powders include Hydroxy Apatite (HA), Fluoridated Hydroxy Apatite (FHA), tricalciumphosphate (TCP), biphasic calcium phosphate (BCP), alumina, zirconina, and silica. A method for producing a photocurable ceramic slurry composition comprising at least one selected from the group consisting of (silica) and bioglass.
According to claim 1,
Dispersants include organic substances containing xylene and acetate, alkylammonium salt copolymer compounds, polyester/polyether-based compounds, copolymers containing phosphoric acid groups, and amine groups. A method for producing a photocurable ceramic slurry composition comprising at least one selected from the group consisting of copolymers.
According to claim 1,
The photocuring initiator is phenylbis(2,4,6-trimethyl benzoylphosphine oxide) (PPO), 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-methyl-1-phenyl-1-propanone. , 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone, methylbenzoyl formate, oxy-phenyl-acetic acid-2-[2-oxo-2 -phenyl-acetoxy-ethoxy]-ethyl ester, oxy-phenyl-acetic acid-2-[2-hydroxy-ethoxy]-ethyl ester, alpha-dimethoxy-alpha-phenylacetophenone, 2-benzyl-2 -(dimethylamino)1-[4-(4-morpholinyl) phenyl]-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl) A method for producing a photocurable ceramic slurry composition comprising at least one selected from the group consisting of -1-propanone and diphenyl (2,4,6-trimethylbenzoyl)-phosphine oxide (TPO).
According to claim 1,
A method for producing a photocurable ceramic slurry composition, wherein the temperature of the photocurable ceramic slurry composition is 20 to 30°C.
Manufactured by the manufacturing method according to claim 1,
Contains campine, photopolymer, ceramic powder, dispersant and photocuring initiator,
A photocurable ceramic slurry composition in which campin exists in a liquid state in the composition at 20 to 30°C, and the crystallization temperature of the campin is 5 to 15°C.
Forming a ceramic slurry layer for 3D printing by applying the photocurable ceramic slurry composition according to claim 9 on a 3D printing bed;
After inducing solidification of the cam pin, forming a ceramic structure by photocuring it into a pre-designed shape;
Forming a porous ceramic structure with micropores by freeze-drying the ceramic structure; and
It includes heat treating the porous ceramic structure at a high temperature,
The temperature of the 3D printing bed is -20 to 15°C.
Method for manufacturing a three-dimensional porous support having a three-dimensionally connected micropore structure.
According to claim 10,
A method of manufacturing a three-dimensional porous support, wherein the thickness of the ceramic slurry layer is controlled to 25 to 200 ㎛ using a doctor blade.
According to claim 10,
A method of producing a three-dimensional porous support, wherein freeze-drying is performed under conditions of a temperature of -70°C to 0°C and a pressure of 0.1 to 20 mTorr.
According to claim 10,
The heat treatment is a method of producing a three-dimensional porous support in which a primary heat treatment is performed at 100 to 600 ° C. for 1 to 40 hours, and then a secondary heat treatment (sintering) is performed at 600 to 1700 ° C. for 1 to 10 hours.
A three-dimensional porous support having a three-dimensionally connected micropore structure manufactured by the method according to claim 10.