Hydroxylation modified ceramic particle, photocuring ceramic slurry and preparation method of photocuring ceramic slurry

Abstract

The invention discloses a hydroxylation modified ceramic particle, a photocuring ceramic slurry and a preparation method thereof.The preparation method of the hydroxylation modified ceramic particle comprises the following steps that after ceramic powder is flatly laid, plasma working gas is introduced into the ceramic powder, a plasma power source is started to generate plasma, the ceramic powder is treated for set time, and the photocuring ceramic slurry is obtained; and uniformly spreading the ceramic powder again, and continuously treating for a set time to obtain the hydroxylation modified ceramic particles. The method for modifying the ceramic particles based on DBD plasma hydroxylation is simple in process, low in cost and easy to regulate and control, the hydroxylation degree of the ceramic particles can be achieved only by adjusting discharge voltage, frequency, treatment time and ventilation flow, no solvent is involved in the hydroxylation modification process of the ceramic particles, almost no waste is generated, and the method is suitable for industrial production. And original ceramic particles are not polluted.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic photocuring additive manufacturing, and relates to a hydroxylated modified ceramic particle, a photocured ceramic slurry and a preparation method thereof, and specifically to the use of dielectric barrier discharge plasma to hydroxylate ceramic particles to prepare a high solid content, low viscosity photocured ceramic slurry. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of 3D printing technology, especially the application of photocuring 3D printing technology in the preparation of complex structure ceramic products is becoming more and more extensive. As the core material of 3D printing, the performance of photocuring ceramic slurry directly affects the printing accuracy, molding quality and production efficiency. However, traditional photocuring ceramic slurry has problems such as low solid content, high viscosity and poor dispersion stability, which limits its application in photocuring 3D printing.

[0004] In order to improve the compatibility and dispersion stability of ceramic particles in slurry, dispersants and surface modifiers are usually used to improve the dispersibility of particles in resin. However, due to the low hydroxyl content on the surface of ceramic particles, the effect of directly using dispersants is not ideal, and over time, the activity of dispersants will continue to decrease, resulting in a gradual deterioration of the dispersion effect. Therefore, increasing the hydroxyl content on the surface of ceramic particles becomes the key to solving this problem. CN 118359428A discloses a method for using hydrogen peroxide and sodium hydroxide oxidant to hydroxylate the surface of ceramic particles to improve the compatibility and dispersion stability of ceramic particles in resin, and this method belongs to the category of wet hydroxylation. However, the wet hydroxylation process steps in this method are cumbersome. On the one hand, it is necessary to accurately control the reaction conditions, such as temperature, pH value, reaction time, etc., which makes it difficult to control the hydroxylation degree of the particles. On the other hand, after the hydroxylation is completed, it is necessary to remove the oxidant mixed with the ceramic particles by washing, drying, sieving and other process methods, which increases the production cost and operation difficulty. If the removal is incomplete, part of the oxidant will remain on the surface of the ceramic particles, polluting the original ceramic powder. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a hydroxylated modified ceramic particle, a photocurable ceramic slurry and a preparation method thereof.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing hydroxylated modified ceramic particles, comprising the following steps:

[0008] After the ceramic powder is spread out, a plasma working gas is introduced into the powder, a plasma power source is started to generate plasma, the ceramic powder is treated for a set time, the ceramic powder is evenly spread out again, and the treatment is continued for a set time to obtain hydroxylated modified ceramic particles.

[0009] Plasma modification technology uses chemically active species such as electrons, ions, free radicals, and excited states generated in gas or liquid discharge plasma to interact with the particle surface, grafting functional groups into the surface microstructure of nanomaterials, thereby exposing more active sites. Among the numerous plasma treatment technologies, dielectric barrier discharge (DBD) is a low-temperature plasma with the characteristics of high electron temperature and low macroscopic temperature. Since DBD plasma can be generated at normal room temperature and atmospheric pressure without the need for vacuum, the generation of non-equilibrium plasma is a relatively simple, cost-effective and easy-to-maintain technology. On the one hand, the energy of electrons can effectively activate relatively stable small molecules to initiate chemical reactions, while the entire reaction system can be maintained at a lower temperature, which is conducive to industrial acceptance, promotion and application. On the other hand, the uniformity of DBD is well adapted to plasma surface modification, making it easy to achieve uniform modification of ceramic particles. Compared with the wet hydroxylation method of ceramic particles disclosed in CN118359428 A, the DBD plasma hydroxylation modification method used in the present invention has a simple process, low cost, and is easy to control. The degree of hydroxylation of ceramic particles can be achieved by adjusting the discharge voltage, frequency, treatment time and ventilation flow rate. Moreover, the hydroxylation modification process of ceramic particles does not involve solvents, produces almost no waste, and will not contaminate the original ceramic particles.

[0010] By subjecting ceramic particles to plasma treatment, hydroxyl (-OH) functional groups can be introduced onto the surface of the ceramic particles, thereby increasing the number of hydroxyl groups on the surface of the ceramic particles. On the one hand, this makes it easier for the hydrophobic groups of the modifier and the free macromolecular long chains of the dispersant to combine with the hydroxyl groups on the surface of the ceramic particles, thereby improving the dispersion efficiency. On the other hand, it provides more active sites for the grafting of the modifier and the dispersant, thereby enhancing the dispersion ability of the particles in the slurry, thereby achieving a high solid content without sacrificing the fluidity of the slurry.

[0011] In some embodiments, the discharge voltage of the plasma power supply is 2-15 kV, the frequency is 10-40 kHz, and the ventilation flow rate is 2-10 L / min.

[0012] In some embodiments, the total time for treating the ceramic powder with plasma is 2-20 minutes.

[0013] In some embodiments, the working gas is at least one of oxygen, nitrogen, argon or water vapor.

[0014] In a second aspect, the present invention provides a hydroxylated modified ceramic particle prepared by the preparation method.

[0015] In some embodiments, the ceramic particles are selected from oxide ceramics, non-oxide ceramics, or bioceramics.

[0016] Preferably, the oxide ceramic is aluminum oxide, silicon oxide or zirconium oxide;

[0017] The non-oxide ceramic is silicon nitride or silicon carbide;

[0018] The bioceramic is hydroxyapatite or tricalcium phosphate.

[0019] In a third aspect, the present invention provides a photocurable ceramic slurry, comprising the following components by volume: 50-60 parts of the hydroxylated modified ceramic particles, 40-50 parts of a photosensitive resin;

[0020] The mass percentage of the photoinitiator to the photosensitive resin is 1%-3%;

[0021] The mass fraction of the plasticizer in the photosensitive resin is 10%-30%;

[0022] The mass percentage of the dispersant to the hydroxylated modified ceramic particles is 2%-10%;

[0023] The mass percentage of the surface modifier in the hydroxylated modified ceramic particles is 2%-10%.

[0024] In some embodiments, the photosensitive resin is selected from at least one of a monofunctional photosensitive resin monomer, a difunctional photosensitive resin monomer, a trifunctional photosensitive resin monomer, or oligomers thereof.

[0025] In some embodiments, the plasticizer is polyethylene glycol (PEG), dibutyl phthalate (DBP), or TXIB.

[0026] In some embodiments, the surface modifier is silane coupling agent KH550, silane coupling agent KH560, silane coupling agent KH570 or oleic acid OA.

[0027] In some embodiments, the dispersant is KOS110, Solsperse41000, BYK-142, Disperbyk-103 or Triton X100.

[0028] In some embodiments, the photoinitiator is bis(2,4,6-trimethylbenzoyl)diphenylphosphine oxide (BAPO) or / and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO).

[0029] In a fourth aspect, the present invention provides a method for preparing the photocurable ceramic slurry, comprising the following steps: mixing and stirring the hydroxylated modified ceramic particles with a surface modifier solution for a set time, and after solid-liquid separation, drying and sieving the solid to obtain the modified ceramic particles;

[0030] The modified ceramic particles, photosensitive resin, plasticizer, photoinitiator and dispersant are mixed homogeneously in vacuum according to proportion to obtain a photocurable ceramic slurry.

[0031] In some embodiments, the rotation speed of the vacuum homogenization is 1000-3000 r / min, and the mixing time of the vacuum homogenization is 5-15 min.

[0032] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0033] Through plasma hydroxylation treatment, the hydroxyl content on the surface of ceramic particles is significantly increased, the affinity of the ceramic particle surface to the resin is increased, and the dispersion and stability of the particles in the slurry are improved, so that the viscosity of the slurry is effectively reduced while maintaining a high solid content. The plasma treatment process is simple, low in energy consumption, short in time, and does not require complex chemical reagents. It avoids the shortcomings of the wet hydroxylation process, such as cumbersome steps, high cost, difficult operation, and difficult to remove residues, thereby reducing production costs.

[0034] The entire preparation process is green and environmentally friendly, meets the sustainable development requirements of modern industrial production, and is suitable for large-scale production. The successful development of this preparation method provides a new idea for the surface modification of other ceramic particles and is expected to be widely used in the preparation of photocurable ceramic slurries. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0036] Figure 1 Schematic diagram of the DBD plasma hydroxylation of ceramic particles in an embodiment of the present invention.

[0037] Figure 2 Flow chart of the process for preparing the photocurable ceramic slurry in an embodiment of the present invention.

[0038] Figure 3 1 and 2 are viscosity curves of Example 1, Example 2, Example 3 and Comparative Example 1 of the present invention.

[0039] Figure 4 These are test diagrams of contact angles of powder pellets and deionized water before (a) and after (b) DBD plasma hydroxylation treatment in Example 1 of the present invention.

[0040] Figure 5 The following are Fourier transform infrared spectra of the aluminum oxide powder without plasma treatment, plasma treatment for 3 minutes, and plasma treatment for 4 minutes. As can be seen from the figure, as the plasma hydroxylation treatment time increases, the aluminum oxide powder at 3350cm -1 -3580cm -1 The hydroxyl vibration peak at also gradually increases. DETAILED DESCRIPTION

[0041] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0042] The present invention will be further described below in conjunction with the embodiments.

[0043] Example 1

[0044] A method for preparing hydroxylated modified ceramic particles, such as Figure 2 As shown, the following steps are included:

[0045] The dielectric barrier discharge plasma platform includes: DBD reactor, plasma power supply, voltage regulator, gas cylinder, pressure reducing valve, oscilloscope, mass flow controller, gas washing bottle, etc. Figure 1 shown.

[0046] The ceramic particles were hydroxylated using a dielectric barrier discharge plasma device: the ceramic powder was spread flat in an upper and lower flat quartz glass reactor, which was connected to the upper and lower electrodes of a DBD reactor. A mixed gas of argon and deionized water was introduced into the reactor, and the gas volume flow was adjusted by a mass flow controller.

[0047] Then, the plasma power supply is started to generate plasma. After treating for 60 seconds, the reactor is taken out and slightly shaken so that the ceramic powder blown away by the plasma gas flow is evenly spread on the quartz glass.

[0048] The generator was started again and the above steps were repeated to ensure that all ceramic particles were treated evenly. The discharge voltage of the plasma treatment was 9 kV, the frequency was 30 kHz, the ventilation flow rate was 4 L / min, and the total discharge time was 120 s.

[0049] The ceramic particles treated with plasma hydroxylation were mixed with the surface modifier KH570 in an ethanol solvent by using an ultrasonic generator and a mechanical stirring device for 1 hour, and then dried in a vacuum drying oven at 100° C. for 5 hours. The modified ceramic particles were sieved with a 100-mesh sieve.

[0050] The photocurable ceramic slurry comprises the following components: the volume fraction of hydroxyapatite / β-tricalcium phosphate / alumina mixed powder is 55 vol%, the volume fraction of photosensitive resin ACMO / HDDA / EO3TMPTA resin premix is ​​40 vol%, the mass fraction of photoinitiator BAPO is 1.5 wt% of the mass of photosensitive resin, the mass fractions of dispersant KOS110 and modifier KH570 are 7 wt% of the mass of ceramic powder respectively, and the mass fraction of plasticizer polyethylene glycol accounts for 15% of the mass of photosensitive resin.

[0051] The photosensitive resin, modified ceramic particles, plasticizer, photoinitiator and dispersant were mixed in proportion by vacuum homogenization using a vacuum homogenizer. The speed of the vacuum homogenizer was 2000 r / min and the mixing time was 5 min to obtain a photocurable ceramic slurry.

[0052] Figure 4 The contact angle test of the powder tablets and deionized water before (a) and after (b) DBD plasma hydroxylation treatment in Example 1 of the present invention. It can be seen from the figure that the contact angle of the powder with deionized water is reduced after plasma hydroxylation treatment, which enhances the hydrophilicity of the powder surface.

[0053] Example 2

[0054] The ceramic particles were hydroxylated using a dielectric barrier discharge plasma device. The ceramic powder was spread flat in an upper and lower flat quartz glass reactor, which was connected to the upper and lower electrodes of the DBD reactor. A mixed gas of argon and deionized water was introduced into the reactor, and the gas volume flow rate was adjusted by a mass flow controller. Then the plasma power supply was started to generate plasma. After 90 seconds of treatment, the reactor was taken out and slightly shaken so that the ceramic powder blown away by the plasma gas flow was evenly spread on the quartz glass. The generator was started again, and the above steps were repeated to ensure that all ceramic particles were evenly treated. The discharge voltage of the plasma treatment was 10 kV, the frequency was 30 kHz, the ventilation flow rate was 3 L / min, and the total discharge time was 180 seconds.

[0055] The photocurable ceramic slurry comprises the following components: a hydroxyapatite / β-tricalcium phosphate / alumina mixed powder having a volume fraction of 55 vol%, a photosensitive resin

[0056] The volume fraction of ACMO / HDDA / EO3TMPTA resin premix is ​​40 vol%, the mass fraction of photoinitiator BAPO is 1.5 wt% of the mass of photosensitive resin, the mass fraction of plasticizer dibutyl phthalate is 25% of the mass of photosensitive resin, and the mass fractions of dispersant KOS110 and modifier KH570 are 8 wt% of the mass of ceramic powder respectively.

[0057] The ceramic particles treated with plasma hydroxylation were mixed with the surface modifier KH570 in an ethanol solvent by using an ultrasonic generator and a mechanical stirring device for 1 hour, and then dried in a vacuum drying oven at 100° C. for 5 hours. The modified ceramic particles were sieved with a 100-mesh sieve.

[0058] The photosensitive resin, modified ceramic particles, plasticizer, photoinitiator and dispersant were mixed in proportion by vacuum homogenization using a vacuum homogenizer. The speed of the vacuum homogenizer was 2000 r / min and the mixing time was 5 min to obtain a photocurable ceramic slurry.

[0059] Example 3

[0060] The ceramic particles were hydroxylated using a dielectric barrier discharge plasma device. The ceramic powder was spread flat in an upper and lower flat quartz glass reactor, which was connected to the upper and lower electrodes of the DBD reactor. A mixed gas of argon and deionized water was introduced into the reactor, and the gas volume flow rate was adjusted by a mass flow controller. Then the plasma power supply was started to generate plasma. After 120 seconds of treatment, the reactor was taken out and slightly shaken so that the ceramic powder blown away by the plasma gas flow was evenly spread on the quartz glass. The generator was started again, and the above steps were repeated to ensure that all ceramic particles were evenly treated. The discharge voltage of the plasma treatment was 10 kV, the frequency was 30 kHz, the ventilation flow rate was 2 L / min, and the total discharge time was 240 seconds.

[0061] The photocurable ceramic slurry includes the following components: the volume fraction of hydroxyapatite / β-tricalcium phosphate / alumina mixed powder is 55 vol%, the volume fraction of photosensitive resin ACMO / HDDA / EO3TMPTA resin premix is ​​40 vol%, the mass fraction of photoinitiator BAPO is 1.5 wt% of the mass of photosensitive resin, the mass fraction of plasticizer polyethylene glycol accounts for 10% of the mass of photosensitive resin, and the mass fractions of dispersant KOS110 and modifier KH570 are 9 wt% of the mass of ceramic powder respectively.

[0062] The ceramic particles treated with plasma hydroxylation were mixed with the surface modifier KH570 in an ethanol solvent by using an ultrasonic generator and a mechanical stirring device for 1 hour, and then dried in a vacuum drying oven at 100° C. for 5 hours. The modified ceramic particles were sieved with a 100-mesh sieve.

[0063] The photosensitive resin, modified ceramic particles, plasticizer, photoinitiator and dispersant were mixed in proportion by vacuum homogenization using a vacuum homogenizer. The speed of the vacuum homogenizer was 2000 r / min and the mixing time was 5 min to obtain a photocurable ceramic slurry.

[0064] Comparative Example 1

[0065] The difference from Example 1 is that the ceramic powder is not subjected to plasma hydroxylation treatment.

[0066] Figure 3 The viscosity curves of Example 1, Example 2, Example 3 and Comparative Example 1 of the present invention are compared. In Comparative Example 1, the ceramic particles were not subjected to plasma hydroxylation treatment, and different plasma process parameters were used to hydroxylate the ceramic particles in Example 1, Example 2 and Example 3. As can be seen from the figure, the viscosity of the photocurable ceramic slurry prepared using the hydroxylated ceramic particles is reduced to varying degrees compared with Comparative Example 1, indicating that it is effective to introduce plasma-treated ceramic particles to prepare a photocurable ceramic slurry with high solid content and low viscosity.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing hydroxylated modified ceramic particles, characterized in that: The steps include: After the ceramic powder is spread out, a plasma working gas is introduced into the powder, a plasma power source is started to generate plasma, the ceramic powder is treated for a set time, the ceramic powder is evenly spread out again, and the treatment is continued for a set time to obtain hydroxylated modified ceramic particles.

2. The method for preparing hydroxylated modified ceramic particles according to claim 1, characterized in that: The discharge voltage of the plasma power supply is 2-15 kV, the frequency is 10-40 kHz, and the ventilation flow rate is 2-10 L / min; The total time for treating the ceramic powder with plasma is 2-20 minutes.

3. The method for preparing hydroxylated modified ceramic particles according to claim 1, characterized in that: The working gas is at least one of oxygen, nitrogen, argon or water vapor.

4. A hydroxylated modified ceramic particle, characterized in that: Prepared by the preparation method described in any one of claims 1 to 3.

5. The hydroxylated modified ceramic particles according to claim 4, characterized in that: The ceramic particles are selected from oxide ceramics, non-oxide ceramics or bioceramics; Preferably, the oxide ceramic is aluminum oxide, silicon oxide or zirconium oxide; The non-oxide ceramic is silicon nitride or silicon carbide; The bioceramic is hydroxyapatite or tricalcium phosphate.

6. A photocurable ceramic slurry, characterized in that: The composition comprises the following components by volume: 50-60 parts of the hydroxylated modified ceramic particles according to claim 4 or 5, and 40-50 parts of a photosensitive resin; The mass percentage of the photoinitiator to the photosensitive resin is 1%-3%; The mass fraction of the plasticizer in the photosensitive resin is 10%-30%; The mass percentage of the dispersant to the hydroxylated modified ceramic particles is 2%-10%; The mass percentage of the surface modifier in the hydroxylated modified ceramic particles is 2%-10%.

7. The photocurable ceramic slurry according to claim 6, characterized in that: The photosensitive resin is selected from at least one of a monofunctional photosensitive resin monomer, a bifunctional photosensitive resin monomer, a trifunctional photosensitive resin monomer or oligomers thereof.

8. The photocurable ceramic slurry according to claim 6, characterized in that: The surface modifier is silane coupling agent KH550, silane coupling agent KH560, silane coupling agent KH570 or oleic acid OA; Preferably, the dispersant is KOS110, Solsperse41000, BYK-142, Disperbyk-103 or Triton X100; Preferably, the photoinitiator is bis(2,4,6-trimethylbenzoyl)diphenylphosphine oxide or / and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide; Preferably, the plasticizer is polyethylene glycol, dibutyl phthalate or TXIB.

9. The method for preparing the photocurable ceramic slurry according to any one of claims 6 to 8, characterized in that: The method comprises the following steps: mixing hydroxylated modified ceramic particles with a surface modifier solution for a set time, and after solid-liquid separation, drying and sieving the solid to obtain modified ceramic particles; The modified ceramic particles, photosensitive resin, plasticizer, photoinitiator and dispersant are mixed homogeneously in vacuum according to proportion to obtain a photocurable ceramic slurry.

10. The method for preparing the light-cured ceramic slurry according to claim 9, characterized in that: The rotation speed of the vacuum homogenizer is 1000-3000r / min, and the mixing time of the vacuum homogenizer is 5-15min.

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