A high-precision photopolymerization 3D printing method for converting microlattice structure precursors into ceramics

Abstract

This invention relates to a high-precision photopolymerization 3D printing method for converting microlattice structure precursor ceramics, belonging to the field of 3D printing ceramics technology. The invention first modifies epoxy silicone resin with acrylic acid, then adds a photoinitiator and a light absorber, and performs photopolymerization 3D printing on the resulting system. After curing, a microlattice structure precursor is obtained, which is then subjected to pyrolysis treatment to obtain the microlattice structure precursor converted ceramic. This invention achieves one-piece photopolymerization 3D printing of microlattice structure precursor converted ceramics, featuring a simple preparation process and high printing precision, providing a direction for the high-precision processing of precursor converted ceramics with complex structures.

Description

Technical Field

[0001] This invention relates to the field of 3D printing ceramics technology, and in particular to a high-precision photopolymerization 3D printing method for converting microlattice structure precursors into ceramics. Background Technology

[0002] Precursor conversion ceramic materials are widely used in high-temperature structural materials, thermal insulation materials, and microwave absorption fields due to their high-temperature stability, high strength, and low dielectric loss.

[0003] In recent years, lattice structures have gained favor among researchers in the field of impact resistance due to their artificially designed periodic structure. Existing research has shown that when material dimensions are reduced to the microscale, their mechanical properties, such as strength and impact resistance, are superior to those of macroscopic structures. Microlattice ceramic structures have significant application potential in aerospace, armor protection, and impact resistance. Therefore, microstructure forming is extremely important in the practical application of ceramic structural materials, and the application requirements of microlattice structures also present significant challenges to the manufacture of precision or complex structures.

[0004] Traditional microlattice structure fabrication techniques are complex, characterized by high processing difficulty, long turnaround times, and difficulty in achieving complex lattice structure formation. 3D printing, a one-piece molding technology, offers significant advantages in the manufacture of complex lattice structures. While techniques such as material extrusion and powder bed fusion are commonly used in 3D printing, their printing precision remains insufficient, typically exceeding 100 micrometers. Photopolymerization 3D printing can achieve high-precision forming, with printing accuracy ranging from micrometers to nanometers, making it suitable for high-precision forming of complex structures in precursor conversion ceramics. However, current research on the fabrication of microstructures in precursor conversion ceramics still faces limitations; processing precision is typically above 200 μm, and further improvements in forming accuracy are needed. Summary of the Invention

[0005] The purpose of this invention is to provide a high-precision photopolymerization 3D printing method for precursor conversion ceramics with microlattice structures, so as to solve the problems existing in the prior art, realize the high-precision printing of complex microlattice structures, and provide a new method for the complex structure and high-precision molding of precursor conversion ceramic materials.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a photopolymerization 3D printing method for converting microlattice structure precursors into ceramics, comprising the following steps:

[0008] (1) Mix epoxy silicone resin, acrylic acid, catalyst and stabilizer, and react to obtain acrylic acid modified epoxy silicone resin.

[0009] (2) Add a photoinitiator and a light absorber to the acrylic-modified epoxy silicone resin;

[0010] (3) The system obtained in step (2) is printed using photopolymerization 3D printing technology, cured and formed to obtain a micro-lattice structure precursor;

[0011] (4) The microlattice structure precursor is pyrolyzed to obtain the microlattice structure precursor converted ceramic.

[0012] In this invention, the epoxy silicone resin is an epoxy-modified organosilicon resin prepared using organoalkoxysilanes as intermediates, and its specific structural formula is as follows:

[0013]

[0014] The structural formula of acrylic-modified epoxy silicone resin is as follows:

[0015]

[0016] As a further preferred embodiment of the present invention, the mass ratio of the epoxy silicone resin to the acrylic acid is 4:1.

[0017] As a further preferred embodiment of the present invention, the catalyst is triethylamine, and the amount added is 4% of the total mass of the epoxy silicone resin and acrylic acid; the stabilizer is p-hydroxyanisole, and the amount added is 0.01% of the total mass of the epoxy silicone resin and acrylic acid.

[0018] As a further preferred embodiment of the present invention, the photoinitiator is (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, and the amount added is 0.2-0.4% of the total mass of the epoxy silicone resin and acrylic acid; the light absorber is Sudan III, and the amount added is 0.03-0.06% of the total mass of the epoxy silicone resin and acrylic acid.

[0019] As a further preferred embodiment of the present invention, the reaction temperature is 100°C and the reaction time is 5 hours.

[0020] As a further preferred embodiment of the present invention, the photopolymerization 3D printing technology is a surface projection micro-stereoscopic 3D printing technology, with a printing layer thickness of 10–40 μm and an exposure intensity of 36–46 mW / cm². 2 The exposure time is 3-5 seconds.

[0021] As a further preferred embodiment of the present invention, the micro-lattice structure is a truss micro-lattice structure, a plate micro-lattice structure, or a micro-curved surface micro-lattice structure.

[0022] As a further preferred embodiment of the present invention, the pyrolysis temperature is 900-1100℃, and the pyrolysis time is 3 hours; the pyrolysis atmosphere is nitrogen or argon. The heating rate from room temperature to the target temperature during the pyrolysis process of the present invention is 1-5℃ / min.

[0023] As a further preferred embodiment of the present invention, the rod diameter or wall thickness of the micro-lattice structure precursor is 50–400 μm.

[0024] The present invention also provides microlattice structure precursor conversion ceramics printed by the above-mentioned photopolymerization 3D printing method.

[0025] Since the epoxy silicone resin used does not possess photocurable properties, this invention modifies it with acrylic acid to give it photocurable characteristics. Subsequently, by adjusting the amounts of photoinitiator and photoabsorber, the photocurability of the resin system is altered, thereby improving its printing accuracy.

[0026] The precursor conversion ceramic of this invention is a SiOC ceramic material.

[0027] The present invention discloses the following technical effects:

[0028] This invention realizes the one-piece photopolymerization 3D printing of precursor conversion ceramics with microlattice structure, which has the characteristics of simple preparation process and high printing accuracy, and provides a direction for high-precision processing of precursor conversion ceramics with complex structure.

[0029] This invention enables the direct printing of micro-lattice structure precursor materials with rod diameter or wall thickness accuracy of 50-400 μm, and the micro-lattice structure precursor conversion ceramics obtained after pyrolysis have an accuracy of 30-180 μm. This fills the gap in high-precision manufacturing of SiOC ceramic micro-lattice structures within the 30-180 μm scale. The prepared high-precision micro-lattice structure precursor conversion ceramics have broad application prospects in electromagnetic wave absorption, communication, and impact-resistant structures. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a process flow diagram of the photopolymerization 3D printing technology of the present invention for printing microlattice structure precursors to ceramics.

[0032] Figure 2 This is a schematic diagram of the photopolymerization 3D printing technology of the present invention;

[0033] Figure 3 This is a model diagram of the printed octet micro-lattice structure in Embodiment 1 of the present invention;

[0034] Figure 4 This is an optical mirror image of the micro-lattice structure 3D printing precursor in Embodiment 1 of the present invention;

[0035] Figure 5 This is a scanning electron microscope image of the micro-lattice structure 3D printing precursor converted into ceramic in Embodiment 1 of the present invention;

[0036] Figure 6 This is a model diagram of the printed I-WP minimal curved surface microlattice structure in Embodiment 2 of the present invention;

[0037] Figure 7 This is a scanning electron microscope image of the 3D printing precursor of the extremely small curved surface microlattice structure in Embodiment 2 of the present invention;

[0038] Figure 8 This is a scanning electron microscope image of the 3D printing precursor of the extremely small curved surface microlattice structure converted into ceramic in Embodiment 2 of the present invention;

[0039] Figure 9 This is a light mirror image of the micro-lattice structure 3D printing precursor in Comparative Example 1 of the present invention.

[0040] Figure 10 The images shown are scanning electron microscope (SEM) images of the micro-lattice structure 3D printing precursor converted ceramic in Comparative Example 2 of this invention; where (a) is an overall surface morphology SEM image and (b) is a local surface morphology SEM image. Detailed Implementation

[0041] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0042] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0043] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0044] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0045] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0046] Figure 1 This is a process flow diagram of the invention for printing microlattice structure precursor conversion ceramics using photopolymerization 3D printing technology;

[0047] Figure 2 This is a schematic diagram of the photopolymerization 3D printing technology of the present invention.

[0048] Example 1

[0049] The steps for high-precision photopolymerization 3D printing of microlattice structure precursors into ceramics are as follows:

[0050] (1) Weigh 200g of epoxy silicone resin, 50g of acrylic acid, 10g of triethylamine and 0.025g of p-hydroxyanisole (MEHQ), and stir them until uniform under magnetic stirring; put the stirred solution in a water bath at 100℃ for 5h to obtain acrylic acid modified epoxy silicone resin.

[0051] (2) Add 1g of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) to the acrylic modified epoxy silicone resin obtained in step (1), stir until dissolved, add 0.15g of Sudan III and sonicate until homogeneous;

[0052] (3) Using photopolymerization 3D printing technology, the system obtained in step (2) is used to print slicing of the octet microlattice structure model with a relative density of 36%, with a printing layer thickness of 20 μm and an exposure intensity of 40 mW / cm. 2 With an exposure intensity of 3 seconds and a rod diameter of 150 μm, a micro-lattice structure 3D printing precursor was obtained.

[0053] (4) The micro-lattice structure 3D printing precursor was placed in a tube furnace and heated from room temperature to 1000℃ at a rate of 1℃ / min. After pyrolysis in a nitrogen atmosphere for 3h, a micro-lattice structure precursor conversion ceramic with an accuracy of 52μm was obtained.

[0054] The epoxy silicone resin used in Example 1 is an epoxy organosilicone modified resin prepared using organoalkoxysilanes as intermediates, with the following structural formula:

[0055]

[0056] The structural formula of the obtained acrylic-modified epoxy silicone resin is as follows:

[0057]

[0058] Example 1: A model diagram of the printed Octet microlattice structure is shown below. Figure 3 The optical microscopy image of the fabricated microlattice structure 3D printing precursor is shown in the figure. Figure 4 Scanning electron microscope image of the microlattice structure precursor transformed into ceramic is shown below. Figure 5 .

[0059] Depend on Figure 3-5 It can be seen that the micro-lattice structure printed in Example 1 is consistent with the design model, and can directly print the octet precursor micro-lattice structure with an accuracy of 150μm. The accuracy of the precursor conversion ceramic obtained after pyrolysis reaches 52μm.

[0060] Example 2

[0061] The only difference from Example 1 is that the printed model is an I-WP minimal curved surface microlattice structure with a volume fraction of 36% and a wall thickness of 55 μm. The printed layer thickness is 10 μm, and the exposure intensity is 42 mW / cm². 2 The exposure intensity was 3s. Then, the printed micro-lattice structure 3D printing precursor was placed in a tube furnace and heated from room temperature to 1000℃ at a rate of 1℃ / min. After pyrolysis in a nitrogen atmosphere for 3h, a micro-lattice structure 3D printing precursor conversion ceramic with a precision of 31μm was obtained.

[0062] The printed I-WP minimal curved surface microlattice structure model diagram in Example 2 is shown below. Figure 6 The scanning electron microscope image of the 3D-printed precursor of the I-WP minimal curved surface microlattice structure is shown in the figure. Figure 7 The scanning electron microscope image of the 3D-printed precursor of the extremely small curved surface microlattice structure for converting ceramics is shown in the figure. Figure 8 .

[0063] Depend on Figure 6-8 It can be seen that the structure printed in Example 2 is consistent with the designed minimal surface model.

[0064] This embodiment can directly print I-WP minimal curved surface micro-lattice structure precursors with a precision of 55μm. The micro-lattice structure precursors obtained after pyrolysis are converted into ceramics with a precision of 31μm, realizing high-precision additive manufacturing of micron-scale lattice structures.

[0065] Example 3

[0066] The only difference from Example 1 is that the printed model is an octet microlattice structure with a volume fraction of 36% and a rod diameter of 400 μm. The printed octet microlattice structure precursor is then placed in a tube furnace and heated from room temperature to 1000°C at a rate of 1°C / min. After pyrolysis in an argon atmosphere for 3 hours, the microlattice structure precursor is converted into ceramic.

[0067] The precision of the lattice structure precursor printed in Example 3 is 400 μm, and the precision of the micro lattice structure precursor converted into ceramic after pyrolysis is 180 μm, which can realize the additive manufacturing of micron-scale lattice structures.

[0068] Example 4

[0069] Step (1) is the same as in Example 1;

[0070] (2) Add 1g of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) to the acrylic modified epoxy silicone resin obtained in step (1), stir until dissolved, add 0.15g of Sudan III and sonicate until homogeneous;

[0071] (3) The system obtained in step (2) was printed by using photopolymerization 3D printing technology. The octet lattice structure model with a relative density of 21% was sliced ​​and printed. The printing parameters were the same as in Example 1. The rod diameter of the model was 200μm, and a micro lattice structure 3D printing precursor was obtained.

[0072] (4) The micro-lattice structure 3D printing precursor was placed in a tube furnace and heated from room temperature to 1000℃ at a rate of 1℃ / min. It was then pyrolyzed for 3h in a nitrogen atmosphere to obtain a micro-lattice structure precursor conversion ceramic with a precision of 120μm.

[0073] Compared with Example 1, this example achieves high-precision printing of micro-lattice structures with lower relative density, resulting in precursor conversion ceramics with a precision of 120 μm.

[0074] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

[0075] Comparative Example 1

[0076] The only difference from Example 1 is that in step (2), the mass of Sudan III light absorber added in this comparative example is 0.05 g. The other preparation steps are the same as in Example 1. The optical microscopy image of the microlattice structure precursor printed in Comparative Example 1 is shown below. Figure 9 .

[0077] Depend on Figure 9 As can be seen, compared with Example 1, the microlattice structure precursor prepared in Comparative Example 1 does not match the design model. Reducing the amount of Sudan III added to 0.05g during the preparation process resulted in extremely poor 3D printing accuracy.

[0078] Comparative Example 2

[0079] The only difference from Example 1 is that 1.5 g of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) was added in step (2) of this comparative example. The other steps are the same as in Example (1). The scanning electron microscope image of the microlattice structure precursor-converted ceramic obtained by Comparative Example 2 is shown below. Figure 10 .

[0080] Depend on Figure 10 As can be seen, the thinnest rod diameter of the 3D-printed precursor conversion ceramic with microlattice structure obtained in Comparative Example 2 is 57 μm, and the rod diameter is not uniform. Compared with Example 1, the microlattice structure printed in Comparative Example 2 does not completely match the design model, and the photocuring properties of the resin system change after increasing the amount of light absorption.

Claims

1. A photopolymerization 3D printing method for converting microlattice structure precursors into ceramics, characterized in that, Includes the following steps: (1) Mix epoxy silicone resin, acrylic acid, catalyst and stabilizer, and react to obtain acrylic acid modified epoxy silicone resin. (2) Add a photoinitiator and a light absorber to the acrylic-modified epoxy silicone resin; (3) The system obtained in step (2) is printed using photopolymerization 3D printing technology, cured and formed to obtain a micro-lattice structure precursor; (4) The microlattice structure precursor is pyrolyzed to obtain the microlattice structure precursor converted ceramic. The structural formula of the epoxy silicone resin is: The mass ratio of the epoxy silicone resin to the acrylic acid is 4:1; The catalyst is triethylamine, and the amount added is 4% of the total mass of the epoxy silicone resin and acrylic acid; the stabilizer is p-hydroxyanisole, and the amount added is 0.01% of the total mass of the epoxy silicone resin and acrylic acid. The photoinitiator is (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, and the amount added is 0.2-0.4% of the total mass of the epoxy silicone resin and acrylic acid; the light absorber is Sudan III, and the amount added is 0.03-0.06% of the total mass of the epoxy silicone resin and acrylic acid. The reaction temperature was 100℃, and the reaction time was 5 hours. The pyrolysis temperature is 900-1100℃, and the pyrolysis time is 3 hours; the pyrolysis atmosphere is nitrogen or argon. The photopolymerization 3D printing technology is a surface projection micro-stereoscopic 3D printing technology, with a printing layer thickness of 10–40 μm and an exposure intensity of 36–46 mW / cm². 2 The exposure time is 3-5 seconds.

2. The photopolymerization 3D printing method according to claim 1, characterized in that, The micro-lattice structure is a truss micro-lattice structure, a plate micro-lattice structure, or a micro-lattice structure with extremely small curved surfaces.

3. The photopolymerization 3D printing method according to claim 1, characterized in that, The rod diameter or wall thickness of the precursor of the microlattice structure is 50–400 μm.

4. The microlattice structure precursor conversion ceramic obtained by the photopolymerization 3D printing method as described in any one of claims 1-3.

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