Zirconia slurry, method for preparing the same, and use thereof

Abstract

The application provides a zirconium oxide slurry and a preparation method and application thereof. The zirconium oxide slurry is prepared by mixing the following components in mass fractions: 80-85% of zirconium oxide, 1.6-3.6% of a dispersing agent, 7.89-14.58% of a photosensitive resin, 1.97-6.25% of a diluent, and 0.1-0.25% of a photosensitive initiator; wherein the diluent is 2,2,4-trimethyl-1,3-pentanediol diisobutyrate. The zirconium oxide slurry prepared by the application has a solid content of 80-85%, and simultaneously has low viscosity (45 DEG C, 2.0-3.0 Pa·S) and fluidity; under the light curing printing debinding procedure, the green body with a large volume is not prone to interlayer cracks or other irregular cracks.

Description

Technical Field

[0001] This invention belongs to the field of printing paste technology, specifically relating to a zirconia paste, its preparation method, and its application. Background Technology

[0002] Photopolymerization technology, namely stereolithography (SL) and digital light processing (DLP), is a type of 3D printing based on the principle of photopolymerization. In 3D printing, ceramic powder is first mixed with liquid photosensitive resin to prepare a photosensitive slurry with a specific solid content and viscosity. Then, a controlled ultraviolet laser scans the surface of the slurry to trigger a photopolymerization reaction, resulting in a preform with polymer-encapsulated powder particles. Finally, the preform is debonded and sintered to obtain the desired part. Photopolymerization technology has gained widespread attention and application due to its high precision, high density of printed parts, and superior mechanical properties.

[0003] At present, there are still two difficulties in the process of photopolymerization printing: (1) In order to ensure precision during the photopolymerization printing process, the photosensitive ceramic slurry must have good low viscosity and fluidity. Therefore, the solid content of the photosensitive ceramic slurry is often not too high; (2) Even under a very slow degreasing process, especially for large-volume green blanks, interlayer cracks or other irregular cracks are easily generated, which seriously affects the product qualification rate. Summary of the Invention

[0004] In view of this, the present invention provides a zirconia slurry, its preparation method and application, which achieves the technical effect of high slurry solid content in the photocuring printing process and less susceptibility to cracking during degreasing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A zirconia slurry is prepared by mixing the following components in parts by weight: 80%–85% zirconia, 1.6%–3.6% dispersant, 7.89%–14.58% photosensitive resin, 1.97%–6.25% diluent, and 0.1%–0.25% photoinitiator;

[0007] The diluent is 2,2,4-trimethyl-1,3-pentanediol diisobutyrate.

[0008] In some specific embodiments, preferably, the zirconia slurry is prepared by mixing the following components in parts by weight: 80% zirconia, 1.6% dispersant, 14.58% photosensitive resin, 3.65% diluent, and 0.17% photoinitiator.

[0009] Furthermore, the zirconium oxide is 3 mol yttrium-stabilized zirconium oxide with a D50 of less than 1 μm.

[0010] Further, the photosensitive resin comprises the following components by weight: 30-40 wt% 4-acryloylmorpholine, 40-60 wt% 1,6-hexanediol diacrylate, and 10-20 wt% 6(ethoxy)trimethylolpropane triacrylate.

[0011] Or 30-40 wt% of 4-acryloylmorpholine, 40-60 wt% of 1,6-hexanediol diacrylate, and 10-20 wt% of trimethylolpropane triacrylate.

[0012] Further, the initiator is any one or a combination of two of 1-hydroxy-cyclohexyl-phenyl ketone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine, and 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone.

[0013] A method for preparing the above-mentioned zirconia slurry includes the following steps: mixing and stirring a dispersant, a photosensitive resin, a diluent, and a photosensitive initiator until homogeneous, then adding zirconia and ball milling to obtain the zirconia slurry.

[0014] Furthermore, the ball milling time is 10–14 hours, and the rotation speed is 260–320 rpm.

[0015] In some specific embodiments, preferably, the ball milling time is 12 hours and the rotation speed is 300 rpm.

[0016] The above-mentioned zirconia slurry is used as a 3D printing slurry in 3D printing.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) The zirconia slurry prepared by the present invention has a solid content of up to 80% to 85%, and at the same time has low viscosity (45℃, 2.0 to 3.0 Pa·S) and fluidity; under the photocuring printing degreasing process, it is not easy to generate interlayer cracks or other irregular cracks for large-volume green blanks.

[0019] (2) The zirconia slurry prepared in this invention contains a low-viscosity, inert diluent, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB). Due to its small molecular weight and low viscosity, TXIB can reduce the viscosity of the zirconia slurry and increase its solid content. Furthermore, it does not participate in the polymerization reaction, thus reducing the internal stress during the polymerization of the photosensitive resin and minimizing various cracking phenomena caused by stress during subsequent degreasing. Additionally, during the degreasing process, it was found that TXIB slowly volatilizes below 200℃, forming certain pores that provide a channel for the subsequent violent decomposition and volatilization of the photosensitive resin, reducing defects such as cracks and bulging during degreasing. Moreover, research has shown that the amount of TXIB added also affects the performance of the final product. The optimal content was determined to be 2.2%–5.4% of the zirconia slurry, at which point the product exhibits the best performance. Attached Figure Description

[0020] Figure 1 These are comparison images of the zirconia paste printing products provided in Examples 1-3 and Comparative Examples 1-3 of the present invention, showing samples with and without defects. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention.

[0022] Key experimental material sources and physicochemical parameters:

[0023] Zirconia was purchased from Dongfang Zirconium Industry, grade: OZ-3Y.

[0024] The dispersant was purchased from Lubrizol, product number: solsperse41000; and from Walker Chemicals... -Disper 41000.

[0025] Unless otherwise specified, all raw materials used in this invention are existing substances that can be purchased directly from the market.

[0026] The specific method for preparing the zirconia slurry of this invention is as follows:

[0027] Take 1.6%–3.6% dispersant, 7.89%–14.58% photosensitive resin, 1.97%–6.25% diluent, and 0.1%–0.25% photosensitive initiator by mass fraction, and mix them evenly. Then, add 80%–85% zirconium oxide in three portions to the mixed liquid. Ball mill the mixture for 10–14 hours at a speed of 260–320 rpm until the zirconium oxide is completely dispersed, thus obtaining a zirconium oxide slurry with high solids content.

[0028] Example 1

[0029] This embodiment provides a zirconium oxide slurry, and the specific steps are as follows:

[0030] Weigh out 30g of 4-acryloylmorpholine (ACMO), 60g of 1,6-hexanediol diacrylate (HDDA), 10g of trimethylolpropane triacrylate (TMPTA), 25g of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB), 1.2g of 1-hydroxy-cyclohexyl-phenyl ketone (184), and 11g of dispersant Solsperse 41000. Mix and stir until homogeneous to obtain a premix. Weigh out 548.7g of zirconia (OZ-3Y grade) and add it to the premix in three portions. Ball mill at 300 rpm for 12 hours, stirring to remove bubbles, to obtain zirconia photosensitive slurry. At this point, the solid content of the zirconia slurry is 80%.

[0031] Example 2

[0032] This embodiment provides a zirconium oxide slurry, and the specific steps are as follows:

[0033] Weigh out ACMO: 40g, HDDA: 40g, TMPTA: 20g, TXIB: 42.9g, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride (TPO): 1.7g, and dispersant. Disper41000: 29.6g, mixed and stirred until homogeneous to obtain a premixed solution. 987.2g of zirconia (OZ-3Y grade) was weighed and added to the premixed solution in three portions. The mixture was ball-milled at 300 rpm for 12 hours, stirred to remove bubbles, and a zirconia photosensitive slurry was obtained. At this point, the solid content of the zirconia slurry was 85%.

[0034] Example 3

[0035] This embodiment provides a zirconium oxide slurry, and the specific steps are as follows:

[0036] Weigh out ACMO: 40g, HDDA: 40g, TMPTA: 20g, TXIB: 45g, initiator TPO: 1.7g, dispersant... Disper 41000:30.0g, mixed and stirred evenly to obtain a premixed solution. Weigh 1001.6g of zirconia (OZ-3Y grade) and add it to the premixed solution in three portions. Ball mill at 300 rpm for 12 hours, stirring and degassing to obtain zirconia photosensitive slurry. At this time, the solid content in the zirconia slurry is 85%.

[0037] Comparative Example 1

[0038] This comparative example provides a zirconium oxide slurry, and the specific steps are as follows:

[0039] Weigh out 30g of ACMO, 60g of HDDA, 10g of TMPTA, 10g of TXIB, 1.2g of initiator TPO, and 9.7g of dispersant Solsperse 41000. Mix and stir until homogeneous to obtain a premix. Weigh out 486.8g of zirconia (OZ-3Y grade) and add it to the premix in three portions. Ball mill the mixture at 300 rpm for 12 hours, stirring to remove bubbles, to obtain a zirconia photosensitive slurry with a solid content of 80%.

[0040] Comparative Example 2

[0041] Weigh out 30g of ACMO, 60g of HDDA, 10g of TMPTA, 25g of polyethylene glycol 400 (PEG400), 1.2g of initiator 184, and 11g of dispersant Solsperse 41000. Mix and stir until homogeneous to obtain a premix. Weigh out 548.7g of zirconia (OZ-3Y grade) and add it to the premix in three portions. Ball mill the mixture at 300 rpm for 12 hours, stirring to remove bubbles, to obtain a zirconia photosensitive slurry with a solid content of 80%.

[0042] Comparative Example 3

[0043] Weigh out 30g of ACMO, 60g of HDDA, 10g of TMPTA, 25g of dibutyl phthalate (DBP), 1.2g of initiator 184, and 11g of dispersant Solsperse 41000. Mix and stir until homogeneous to obtain a premix. Weigh out 548.7g of zirconia (OZ-3Y grade) and add it to the premix in three portions. Ball mill the mixture at 300 rpm for 12 hours, stirring to remove bubbles, to obtain a zirconia photosensitive slurry with a solid content of 80%.

[0044] Performance testing of zirconia photosensitive paste

[0045] Furthermore, to investigate the performance of the zirconia photosensitive paste, green printing was performed on the zirconia photosensitive pastes prepared in Examples 1-3 and Comparative Examples 1-3, and the performance of the obtained samples was measured. The specific operations are as follows:

[0046] The above-mentioned slurries were printed into green bodies using a ceramic photopolymer SLA printer. The printed green bodies were then degreased and sintered using the same degreasing procedure to obtain zirconia ceramic products. The degreasing procedure was as follows: heating from 35℃ to 100℃ at a rate of 0.2℃ / min, holding at 100℃ for 2 hours; heating from 100℃ to 200℃ at a rate of 0.2℃ / min, holding at 200℃ for 2 hours; heating from 200℃ to 300℃ at a rate of 0.2℃ / min, holding at 300℃ for 2 hours; and heating from 300℃ to 550℃ at a rate of 0.5℃ / min, holding at 550℃ for 2 hours to complete the degreasing process. The sintering procedure involved heating to 1480℃ at a rate of 3℃ / min and holding at that temperature.

[0047] To compare the defect improvement effects of different slurries, 40mm*6mm*4mm samples were printed, and the percentage of samples with cracks was calculated to compare the defect situation. The viscosity of the slurry at 45℃ was tested using a rotational viscometer. Under the same power and scanning speed, a 355nm laser scan was used to form a cured monolayer in one pass, and the monolayer thickness was measured using a micrometer to evaluate the curing ability of different slurries.

[0048] Table 1. Performance parameters of the zirconia slurries prepared in Examples 1-3 and Comparative Examples 1-3

[0049] project Viscosity (45℃), Pa·S Curing depth, μm Defect rate Example 1 2.6 100 0％ Example 2 3.0 90 0％ Example 3 2.0 70 0％ Comparative Example 1 3.1 105 40％ Comparative Example 2 2.9 100 20％ Comparative Example 3 2.8 100 20％

[0050] The results of Examples 1-3 and Comparative Example 1 show that the presence of a certain amount of inert diluent TXIB can greatly reduce crack defects; however, when the amount of inert diluent TXIB is excessive, it has a certain adverse effect on the curing depth. Therefore, the content of inert diluent TXIB is an important factor affecting product performance.

[0051] The results of Example 1 and Comparative Examples 2 and 3 show that the inert diluent TXIB is significantly better than DBP and PEG400 in terms of defect rate. This is because TXIB has a lower viscosity, which can reduce the viscosity of the slurry and reduce degreasing defects.

[0052] The zirconia slurries prepared in Examples 1-3 and Comparative Examples 1-3 were used for printing. The samples were stained with ink and the surface ink was quickly rinsed off. Samples with and without cracks were selected for comparative observation. The results are shown in […]. Figure 1 As can be seen from Figure 1, when the sample with cracks was soaked in ink, the ink entered the cracks, while the surface of the sample without cracks remained clean and smooth.

[0053] This invention reduces internal stress during the printing process and achieves low viscosity by determining the mass ratio of each component and selecting a specific inert diluent to prepare the zirconia slurry. This results in a slurry with good low viscosity and fluidity, making the printed product less prone to interlayer cracks or other irregular cracks.

[0054] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A zirconia slurry, characterized by, Prepared by mixing the following components in percentage by mass: zirconium oxide 80% to 85%, dispersant 1.6% to 3.6%, photosensitive resin 7.89% to 14.58%, diluent 1.97% to 6.25%, and photosensitive initiator 0.1% to 0.25%; wherein the diluent is 2,2,4-trimethyl-1,3-pentanediol diisobutyrate; The zirconium oxide is 3 mol yttrium stabilized zirconium oxide with a D50 of less than 1 μm; The photosensitive resin comprises the following components in percentage by mass: 4-acryloylmorpholine 30 to 40 wt%, 1,6-hexanediol diacrylate 40 to 60 wt%, and 6(ethoxyl)trimethylolpropane triacrylate 10 to 20 wt%; or 4-acryloylmorpholine 30 to 40 wt%, 1,6-hexanediol diacrylate 40 to 60 wt%, and trimethylolpropane triacrylate 10 to 20 wt%.

2. The zirconia slurry of claim 1, wherein, The zirconium oxide slurry is prepared by mixing the following components in percentage by mass: zirconium oxide 80%, dispersant 1.6%, photosensitive resin 14.58%, diluent 3.65%, and photosensitive initiator 0.17%.

3. Zirconia slurry according to claim 1 or 2, characterized in that The initiator is any one or a combination of 1-hydroxy-cyclohexyl-phenyl ketone, diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide, and 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzyl) butanone.

4. A process for the preparation of the zirconia slurry according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: mixing and stirring the dispersant, photosensitive resin, diluent, and photosensitive initiator until uniform, then adding the zirconium oxide and ball milling to obtain the zirconium oxide slurry.

5. The method of claim 4, wherein, The ball milling time is 10 to 14 h and the rotation speed is 260 to 320 rpm.

6. The method of claim 5, wherein, The ball milling time is 12 h and the rotation speed is 300 rpm.

7. Use of the zirconium oxide slurry of any one of claims 1 to 3 as a printing slurry in light-cured printing.

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