3D printing ceramic slurry based on composite hyaluronic acid and thixotropic regulation and control method thereof

Abstract

The invention discloses a 3D printing ceramic slurry based on composite hyaluronic acid and a thixotropic regulation and control method thereof, the slurry comprises the following components: 50-85 vol% of ceramic powder as a main skeleton component of the slurry; and 0.2-0.5 wt% of a composite hyaluronic acid dispersant (accounting for the mass of the powder), and synergistic optimization of thixotropic properties is realized through compounding in a specific proportion. According to the invention, the high thixotropic index (gt; gt) is realized for the first time through the compounding ratio of the medium polymer HA to the high polymer HA of 70: 30; 3.5) with a low extrusion pressure (lt; and the contradiction between thixotropy and fluidity in the traditional technology is solved through collaborative optimization of the extrusion die (6, 6 bar), and the extrusion smoothness and the stacking precision in the printing process are guaranteed. When a high-aspect-ratio ceramic structure is printed, the deformation rate is lt when the suspension angle is larger than or equal to 60 degrees; the minimum layer thickness is smaller than or equal to 0.15 mm, and the forming precision of a complex structure is remarkably improved.

Description

Technical Field

[0001] This invention relates to the fields of ceramic additive manufacturing and biomaterials technology, specifically to 3D printing ceramic slurry based on composite hyaluronic acid and its thixotropic regulation method. Background Technology

[0002] In ceramic 3D printing technology, the thixotropic properties of the slurry are crucial for printing accuracy and structural stability. A slurry with good thixotropy should exhibit shear-thinning properties, reducing viscosity when subjected to shear during printing for easier extrusion; and rapidly recovering structural strength after shearing ceases to ensure stacking accuracy. However, existing technologies suffer from the following problems:

[0003] Single molecular weight hyaluronic acid (such as CN113896689A which uses 300kDa single molecule HA) is difficult to balance thixotropic index and extrusion flowability in high solid content ceramic slurry. The thixotropic index is usually below 2.0, and the structure recovery time is long, which makes the printed structure easy to deform and collapse.

[0004] The improvement in thixotropic properties of compound systems (such as JP2020152001A which uses a compound of HA and sodium alginate) is limited, with a thixotropic index of only 2.8, which cannot meet the printing requirements of high aspect ratio ceramic structures (such as turbine impellers).

[0005] Traditional understanding holds that while high-molecular-weight HA can improve thixotropy, it also increases extrusion resistance; while medium-molecular-weight HA can improve flowability, it reduces yield stress. The synergistic gain mechanism between the two has not been effectively explored. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a 3D printing ceramic slurry based on composite hyaluronic acid and its thixotropic control method, thus solving the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a 3D printing ceramic slurry based on composite hyaluronic acid, the slurry comprising the following components:

[0008] Ceramic powder: 50-85 vol%, as the main skeleton component of the slurry;

[0009] Composite hyaluronic acid dispersant: 0.2-0.5 wt% (by powder mass), thixotropic properties are synergistically optimized through specific compounding ratios;

[0010] Deionized water: 12-25 vol%, used as a solvent to adjust the fluidity of the slurry.

[0011] Preferably, the composite hyaluronic acid dispersant is composed of 68-72% medium-molecular-weight HA and 28-32% high-molecular-weight HA, wherein the molecular weight of the medium-molecular-weight HA is 150-200 kDa and the molecular weight of the high-molecular-weight HA is 500-800 kDa.

[0012] Preferably, the rheological properties of the slurry satisfy the following:

[0013] The thixotropic index is 3.5-4.2 (10s). -1 / 100s -1 The shear rate ratio is significantly higher than that of conventional slurries (<2.0), ensuring a significant reduction in viscosity under shear and rapid structural recovery after shearing stops; the yield stress is 250-350 Pa, ensuring suitable anti-flow capability of the slurry during printing and preventing flow in unprinted areas; the structural recovery time is 3-5 seconds (step shear test, from 1000 s). -1 →1s -1 Compared to single-molecular-weight HA, it accelerates the process by 60%, enabling rapid recovery of structural strength and ensuring stacking accuracy.

[0014] A thixotropic modulation method for 3D printing ceramic slurry based on composite hyaluronic acid includes the following steps:

[0015] Step 1: Dissolve medium-molecular-weight HA in deionized water at 40-45℃ and stir with a magnetic stirrer for 30 minutes to fully dissolve the medium-molecular-weight HA and form a homogeneous solution.

[0016] Step 2: Dissolve the polymer HA in deionized water at 60℃ and disperse it at 2000 rpm for 20 minutes to promote full dispersion of the polymer HA and avoid agglomeration.

[0017] Step 3: Slowly add the solution obtained in Step 2 to the solution obtained in Step 1 at a rate of ≤50mL / min to ensure that the two solutions are mixed evenly and to avoid adverse reactions caused by excessively high local concentrations.

[0018] Step 4: Filter the mixture through a 100μm filter to remove any impurities or undissolved particles. Then add ceramic powder for subsequent slurry preparation.

[0019] 3D printing equipment using 3D printing ceramic slurry based on composite hyaluronic acid, including a temperature-controlled extrusion system, a pressure fluctuation compensation module, and a micro-vibration nozzle;

[0020] Temperature-controlled extrusion system: The barrel is divided into zones with temperature control, specifically 25°C for the feeding section and 35°C for the extrusion section;

[0021] The pressure fluctuation compensation module adjusts the air pressure in real time with a control accuracy of ±0.3 bar;

[0022] The micro-vibration nozzle has an amplitude of 5-10 μm and a frequency of 50 Hz to prevent HA gel clogging.

[0023] Application of composite hyaluronic acid-based 3D printing ceramic slurry in printing high aspect ratio ceramic structures

[0024] In printing high aspect ratio ceramic structures, the deformation rate is <3% when the overhang angle is ≥60°; the minimum layer thickness is ≤0.15mm.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] This invention, through a 70:30 blend of medium and high molecular weight HA, achieves for the first time a synergistic optimization of high thixotropic index (>3.5) and low extrusion pressure (<6 bar), resolving the contradiction between thixotropy and flowability in traditional technologies, and ensuring smooth extrusion and stacking accuracy during the printing process. When printing high aspect ratio ceramic structures, the deformation rate is <3% with a droop angle ≥60° and the minimum layer thickness is ≤0.15mm, significantly improving the forming accuracy of complex structures. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a technical solution: a 3D printing ceramic slurry based on composite hyaluronic acid. This slurry comprises the following components:

[0029] Ceramic powder: 50-85 vol%, as the main skeleton component of the slurry;

[0030] Composite hyaluronic acid dispersant: 0.2-0.5 wt% (by powder mass), thixotropic properties are synergistically optimized through specific compounding ratios;

[0031] Deionized water: 12-25 vol%, used as a solvent to adjust the fluidity of the slurry.

[0032] The composite hyaluronic acid dispersant consists of 68-72% medium-molecular-weight HA and 28-32% high-molecular-weight HA. The molecular weight of the medium-molecular-weight HA is 150-200kDa, and the molecular weight of the high-molecular-weight HA is 500-800kDa.

[0033] The rheological properties of the slurry meet the following requirements:

[0034] The thixotropic index is 3.5-4.2 (10s). -1 / 100s -1 The shear rate ratio is significantly higher than that of conventional slurries (<2.0), ensuring a significant reduction in viscosity under shear and rapid structural recovery after shearing stops; the yield stress is 250-350 Pa, ensuring suitable anti-flow capability of the slurry during printing and preventing flow in unprinted areas; the structural recovery time is 3-5 seconds (step shear test, from 1000 s). -1 →1s -1 Compared to single-molecular-weight HA, it accelerates the process by 60%, enabling rapid recovery of structural strength and ensuring stacking accuracy.

[0035] A thixotropic modulation method for 3D printing ceramic slurry based on composite hyaluronic acid includes the following steps:

[0036] Step 1: Dissolve medium-molecular-weight HA in deionized water at 40-45℃ and stir with a magnetic stirrer for 30 minutes to fully dissolve the medium-molecular-weight HA and form a homogeneous solution.

[0037] Step 2: Dissolve the polymer HA in deionized water at 60℃ and disperse it at 2000 rpm for 20 minutes to promote full dispersion of the polymer HA and avoid agglomeration.

[0038] Step 3: Slowly add the solution obtained in Step 2 to the solution obtained in Step 1 at a rate of ≤50mL / min to ensure that the two solutions are mixed evenly and to avoid adverse reactions caused by excessively high local concentrations.

[0039] Step 4: Filter the mixture through a 100μm filter to remove any impurities or undissolved particles. Then add ceramic powder for subsequent slurry preparation.

[0040] 3D printing equipment using 3D printing ceramic slurry based on composite hyaluronic acid, including a temperature-controlled extrusion system, a pressure fluctuation compensation module, and a micro-vibration nozzle;

[0041] Temperature-controlled extrusion system: The barrel is divided into zones with temperature control, specifically 25°C for the feeding section and 35°C for the extrusion section;

[0042] The pressure fluctuation compensation module adjusts the air pressure in real time with a control accuracy of ±0.3 bar;

[0043] The micro-vibration nozzle has an amplitude of 5-10 μm and a frequency of 50 Hz to prevent HA gel clogging.

[0044] Application of composite hyaluronic acid-based 3D printing ceramic slurry in printing high aspect ratio ceramic structures

[0045] In printing high aspect ratio ceramic structures, the deformation rate is <3% when the overhang angle is ≥60°; the minimum layer thickness is ≤0.15mm.

[0046] Example: Preparation of composite hyaluronic acid 3D printing ceramic slurry

[0047] Raw material preparation: Weigh 80 vol% ceramic powder (alumina), 0.3 wt% composite hyaluronic acid dispersant (70% medium molecular weight HA, molecular weight 180 kDa; 30% high molecular weight HA, molecular weight 600 kDa), and 17 vol% deionized water.

[0048] Solution preparation:

[0049] Add medium-molecular-weight HA to deionized water at 40°C and stir magnetically for 30 minutes until completely dissolved.

[0050] Add the polymer HA to deionized water at 60°C and disperse at 2000 rpm for 20 minutes to form a homogeneous solution.

[0051] Mixing and filtration: The high molecular weight HA solution was slowly added to the medium molecular weight HA solution at a rate of 40 mL / min. After stirring evenly, the mixture was filtered through a 100 μm filter.

[0052] Slurry preparation: The filtered mixture is mixed with ceramic powder and stirred evenly to obtain 3D printing ceramic slurry.

[0053] Comparative Example 1: Single polymer HA slurry (molecular weight 150kDa).

[0054] Comparative Example 2: Single polymer HA slurry (molecular weight 600kDa).

[0055] The embodiments of the present invention are compared with Comparative Examples 1 and 2, and the results are shown in the table below:

[0056]

[0057] In summary, this invention, through a 70:30 blend of medium and high molecular weight HA, achieves for the first time a synergistic optimization of high thixotropic index (>3.5) and low extrusion pressure (<6 bar), resolving the contradiction between thixotropy and flowability in traditional technologies, and ensuring smooth extrusion and stacking accuracy during the printing process. When printing high aspect ratio ceramic structures, the deformation rate is <3% when the overhang angle is ≥60°, and the minimum layer thickness is ≤0.15mm, significantly improving the forming accuracy of complex structures.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A 3D printing ceramic slurry based on composite hyaluronic acid, characterized in that, This slurry contains the following components: Ceramic powder: 50-85 vol%; Composite hyaluronic acid dispersant: 0.2-0.5 wt%; Deionized water: 12-25 vol%.

2. The 3D printing ceramic slurry based on composite hyaluronic acid according to claim 1, characterized in that, The composite hyaluronic acid dispersant is composed of 68-72% medium-molecular-weight HA and 28-32% high-molecular-weight HA. The molecular weight of the medium-molecular-weight HA is 150-200 kDa, and the molecular weight of the high-molecular-weight HA is 500-800 kDa.

3. The 3D printing ceramic slurry based on composite hyaluronic acid according to claim 1, characterized in that, The rheological properties of the slurry satisfy: The thixotropic index is 3.5-4.2; the yield stress is 250-350 Pa; and the structural recovery time is 3-5 seconds.

4. The thixotropic control method for 3D printing ceramic slurry based on composite hyaluronic acid according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Dissolve medium-molecular-weight HA in deionized water at 40-45℃ and stir with a magnetic stirrer for 30 minutes to fully dissolve the medium-molecular-weight HA and form a homogeneous solution. Step 2: Dissolve the polymer HA in deionized water at 60℃ and disperse it at 2000 rpm for 20 minutes to promote full dispersion of the polymer HA and avoid agglomeration. Step 3: Slowly add the solution obtained in Step 2 to the solution obtained in Step 1 at a rate of ≤50mL / min to ensure that the two solutions are mixed evenly and to avoid adverse reactions caused by excessively high local concentrations. Step 4: Filter the mixture through a 100μm filter to remove any impurities or undissolved particles. Then add ceramic powder for subsequent slurry preparation.

5. A 3D printing apparatus using the composite hyaluronic acid-based 3D printing ceramic slurry as described in any one of claims 1-3, characterized in that, This includes a temperature-controlled extrusion system, a pressure fluctuation compensation module, and a micro-vibration nozzle; Temperature-controlled extrusion system: The barrel is divided into zones with temperature control, specifically 25°C for the feeding section and 35°C for the extrusion section; The pressure fluctuation compensation module adjusts the air pressure in real time with a control accuracy of ±0.3 bar; The micro-vibration nozzle has an amplitude of 5-10 μm and a frequency of 50 Hz to prevent HA gel clogging.

6. The application of the 3D printing ceramic slurry based on composite hyaluronic acid according to any one of claims 1-2 in printing high aspect ratio ceramic structures, characterized in that: In printing high aspect ratio ceramic structures, the deformation rate is <3% when the overhang angle is ≥60°; the minimum layer thickness is ≤0.15mm.

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