Photocuring 3D printing copper slurry as well as preparation method and application thereof

Abstract

The invention discloses photocuring 3D printing copper slurry and a preparation method and application thereof. Relates to the technical field of 3D printing. The photocuring 3D printing copper paste comprises the following components: urethane acrylate; copper powder; a photoinitiator; a thermal polymerization inhibitor; an anti-copper agent; the copper-resistant agent is selected from at least one of benzotriazole, a benzotriazole derivative, 3-mercaptopropionic acid, triphenyl phosphate, triphenyl phosphate and trimethyl phosphate; the copper powder is composed of copper particles with the average particle size of 0.3-1 micron, 3-5 microns and 10-20 microns. The photocuring 3D printing copper paste has the advantages of being good in stability, free of spontaneous curing, long in quality guarantee period, high in forming precision and the like, and obvious sedimentation and self-curing phenomena are achieved when the photocuring 3D printing copper paste is stored for 60 days under the normal-temperature dark condition; and no obvious sedimentation and self-curing phenomena exist after the coating is stored for 180 days under the low-temperature dark condition of 0-4 DEG C.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to a photopolymerizable 3D printing copper paste, its preparation method, and its application. Background Technology

[0002] With the continuous advancement of technology, metal 3D printing technology has been widely applied in manufacturing, especially in aerospace, automotive, medical, and precision engineering fields. However, although existing technologies such as selective laser melting (SLM) provide convenient solutions for manufacturing metal parts, significant challenges remain in the printing process of certain metals. Copper, due to its excellent electrical conductivity, thermal conductivity, and ductility, has important application value in many fields such as electrical engineering, mechanical manufacturing, biomedicine, aerospace, and petrochemicals. However, the manufacturing of copper in metal 3D printing faces numerous difficulties, especially when using traditional SLM technology. Copper's low laser absorption rate and high thermal conductivity lead to frequent defects during the printing process, limiting its application scope.

[0003] Copper has a high reflectivity, especially for lasers with wavelengths greater than 1060nm, where its reflectivity exceeds 90%. This makes it difficult for traditional SLM technology to effectively absorb the laser, hindering efficient copper melting. Furthermore, copper has high thermal conductivity, resulting in a large thermal gradient during the forming process, which can easily lead to defects such as curling, cracking, and delamination on the surface of parts. At the same time, copper's high ductility makes post-processing, particularly powder removal and recycling, quite challenging. Therefore, although SLM technology has wide applications in metal 3D printing, its high equipment cost, energy consumption, and stringent environmental requirements limit its ability to manufacture intricate and complex micro-sized copper parts, necessitating a more efficient and energy-saving alternative technology.

[0004] Photopolymer 3D printing technology offers a promising innovative solution for the additive manufacturing of copper. This technology mixes copper powder with photosensitive resin to form a copper slurry. Under ultraviolet light, the resin is cured to form a preliminary metal preform. Subsequently, debinding and sintering remove organic components, ultimately yielding high-density copper parts. Unlike SLM technology, photopolymer 3D printing does not require high-energy laser melting, avoiding the high reflectivity of copper and overcoming the shortcomings of traditional metal 3D printing techniques. Through the selective curing of the photopolymer resin, the forming process can be precisely controlled, resulting in high forming accuracy, good surface quality, and low energy consumption. This makes photopolymer 3D printing technology uniquely advantageous in the manufacture of complex micro-sized parts.

[0005] However, the preparation of copper paste still faces some technical challenges in the photopolymerization 3D printing process. First, the high density of metallic copper makes it prone to sedimentation in the resin, which affects the uniformity and stability of the copper paste, and consequently the molding quality.

[0006] Furthermore, the reflection and scattering of light by copper particles pose a significant challenge in photopolymer 3D printing. Because copper particles reflect and scatter light under ultraviolet light, some light energy cannot effectively penetrate into the resin, thus reducing the curing depth and photopolymerization efficiency. This not only affects the quality of the printed product but may also lead to longer printing times and increased energy consumption.

[0007] Furthermore, the oxidation of copper during high-temperature debinding and sintering is also a key challenge in the fabrication of high-performance metal parts. During sintering, copper readily reacts with oxygen in the air to form copper oxide, which affects the density and properties of the metallic material.

[0008] The aforementioned technical challenges have resulted in problems with existing photopolymer 3D printing copper pastes, including poor stability, easy spontaneous curing, short shelf life (usually less than 7 days), and low forming accuracy (printed structural feature size is usually greater than 300μm).

[0009] Therefore, there is an urgent need to develop a new copper paste suitable for photopolymer 3D printing and its preparation method to achieve the manufacturing of high-precision, complex, and miniature copper metal parts. Summary of the Invention

[0010] The purpose of this invention is to provide a photocurable 3D printing copper paste with good stability, non-self-curing properties, and high forming accuracy.

[0011] The first aspect of the present invention is:

[0012] A photopolymerizable 3D printing copper paste is provided.

[0013] The second aspect of the present invention is:

[0014] A method for preparing photopolymerizable 3D printing copper paste is provided.

[0015] The third aspect of the present invention is:

[0016] Application of the photocurable 3D printing copper paste.

[0017] Specifically, the technical solution adopted according to the first aspect of the present invention is as follows:

[0018] A photopolymerizable 3D printing copper paste comprises the following components:

[0019] Polyurethane acrylate;

[0020] Copper powder;

[0021] Photoinitiator;

[0022] Heat-resistant polymerization inhibitor;

[0023] Copper inhibitor;

[0024] The copper inhibitor is selected from at least one of benzotriazole, benzotriazole derivatives, 3-mercaptopropionic acid, triphenyl phosphate, triphenyl phosphite, and trimethyl phosphate.

[0025] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0026] The photocurable 3D printing copper paste of the present invention has the advantages of good stability, non-self-curing, long shelf life, and high forming accuracy. It can be stored at room temperature in the dark for 60 days without obvious sedimentation or self-curing; it can be stored at low temperature (0-4℃) in the dark for 180 days without obvious sedimentation or self-curing; and the minimum feature size of the printable structure of the photocurable 3D printing copper paste is as low as 100μm.

[0027] This invention uses a thermal inhibitor to capture active free radicals in an organic system, preventing or terminating free radical chain reactions and inhibiting spontaneous curing of the slurry caused by temperature rise.

[0028] This invention employs a copper-resistant agent to inhibit the catalytic activity of copper powder on organic systems by forming a protective film on the surface of copper particles or by binding with free copper ions to form a stable chelate. Furthermore, this invention specifies that the copper-resistant agent is selected from at least one of benzotriazole, benzotriazole derivatives, 3-mercaptopropionic acid, triphenyl phosphate, triphenyl phosphite, and trimethyl phosphate, thereby making the copper paste more suitable for photopolymerization 3D printing by selecting a suitable copper-resistant agent.

[0029] Through the synergistic effect of thermal inhibitors and copper inhibitors, the self-curing phenomenon caused by environmental temperature fluctuations, mechanical friction or exothermic reaction during the preparation, storage and use of copper paste can be avoided. On the other hand, the over-curing problem caused by the heat released by the photocuring reaction of the paste spreading to non-target areas during the photocuring 3D printing process can be solved, thereby improving the forming accuracy of 3D printing.

[0030] According to one embodiment of the present invention, the photocurable 3D printing copper paste comprises the following components in parts by weight:

[0031] Polyurethane acrylate, 2-30 parts;

[0032] Copper powder, 60-94 parts;

[0033] Photoinitiator, 0.02–5 parts;

[0034] Heat-inhibiting polymerization agent, 0.002–0.5 parts;

[0035] Copper inhibitor, 0.005 to 2 parts.

[0036] According to one embodiment of the present invention, the photocurable 3D printing copper paste comprises the following components in parts by weight:

[0037] Polyurethane acrylate, 2-15 parts;

[0038] Copper powder, 80-92 parts;

[0039] Photoinitiator, 0.1–2 parts;

[0040] Heat-inhibiting polymerization agent, 0.003–0.2 parts;

[0041] Copper inhibitor, 0.01 to 1 part.

[0042] According to one embodiment of the present invention, the components of the photocurable 3D printing copper paste further include additives.

[0043] According to one embodiment of the present invention, the copper powder is composed of copper particles with average particle sizes of 0.3-1 μm, 3-5 μm and 10-20 μm.

[0044] The main organic component of the photopolymer 3D printing copper paste of this invention is polyurethane acrylate. By combining copper powder with polyurethane acrylate at different particle sizes, this invention greatly improves the sedimentation problem of copper particles, giving the copper paste of this invention excellent stability and light transmittance.

[0045] According to one embodiment of the present invention, the additives include a diluent and a dispersant. The present invention adjusts the viscosity of the photocurable 3D printing copper paste by adding a diluent and a dispersant together.

[0046] According to one embodiment of the present invention, the diluent is present in 2 to 40 parts by weight in the photocurable 3D printing copper paste.

[0047] According to one embodiment of the present invention, the dispersant in the photocurable 3D printing copper paste is 0.01 to 8 parts by weight.

[0048] According to some embodiments of the present invention, the diluent includes at least one of polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, diethanol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, and ethoxylated pentaerythritol tetraacrylate. The diluent functions to reduce the viscosity of the copper paste and increase the crosslinking density of the cured green body, thereby improving the mechanical strength of the green body and enabling it to be used for photopolymerization 3D printing of high-precision structures.

[0049] According to some embodiments of the present invention, the dispersant is at least one selected from KOS110, BYK110, BYK111, oleic acid, stearic acid, and silane coupling agent. The function of the dispersant is to enable the copper powder to be uniformly dispersed in the resin, preventing the copper particles from agglomerating and settling.

[0050] According to some embodiments of the present invention, the copper powder is composed of copper particles with average particle sizes of 0.3-1 μm, 3-5 μm, and 10-20 μm, wherein the 0.3-1 μm copper powder accounts for 0.1-50% of the total copper powder by mass, the 3-5 μm copper powder accounts for 0.1-60% of the total copper powder by mass, and the 10-20 μm copper powder accounts for 0.1-80% of the total copper powder by mass. Larger particle sizes of copper powder in the photocurable 3D printing copper paste have better ultraviolet light penetration and the paste cures more easily, but the paste has poor stability and is very prone to settling. Conversely, smaller particle sizes of copper powder in the photocurable 3D printing copper paste have relatively poorer ultraviolet light penetration and the paste does not cure as easily, but the paste has better stability and is less prone to settling. Based on this, the present invention improves light penetration and paste flowability, reduces light scattering, and improves printing resolution through multi-particle size gradation.

[0051] According to some embodiments of the present invention, the photoinitiator includes at least one selected from diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-isopropylthioxanone, and 2,4-diethylthiazolone. The photoinitiator imparts photoreactivity to the copper paste, enabling it to be used for photopolymerization 3D printing. This invention improves photopolymerization efficiency and reduces exposure time through the selection of highly reactive photoinitiators.

[0052] According to some embodiments of the present invention, the polyurethane acrylate includes at least one selected from aromatic polyurethane acrylate, aliphatic polyurethane acrylate, aliphatic polyurethane diacrylate, and aliphatic polyurethane hexaacrylate. By selecting a specific type of polyurethane acrylate, the viscosity and curing efficiency of the slurry are further optimized, and the coating ability of copper powder is enhanced.

[0053] According to some embodiments of the present invention, the heat-inhibiting polymerization agent is at least one selected from hydroquinone, hydroquinone monomethyl ether, diphenylamine, diphenylamine sulfide, tert-butylcatechol, phenothiazine, and 2,2,6,6-tetramethylpiperidine oxide. The present invention effectively inhibits free radical chain reactions and prevents thermally induced self-curing of the slurry during storage and printing by selecting specific heat-inhibiting polymerization agents.

[0054] Specifically, the technical solution adopted according to the second aspect of the present invention is as follows:

[0055] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0056] The polyurethane acrylate, photoinitiator, thermal inhibitor and copper inhibitor are mixed and then the copper powder is added and stirred to disperse, thus obtaining the photocurable 3D printing copper paste.

[0057] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0058] This invention uses a step-by-step mixing process to ensure that each component is fully dispersed, avoid copper powder agglomeration, and improve the uniformity of the slurry.

[0059] According to one embodiment of the present invention, the instruments used for stirring and dispersing include a planetary ball mill, a vacuum homogenizer, and a three-roll mill. Preferably, the instruments used for stirring and dispersing include a three-roll mill and a vacuum homogenizer.

[0060] According to one embodiment of the present invention, the planetary ball mill rotates at a speed of 200-600 rpm for 2-8 hours.

[0061] According to one embodiment of the present invention, the stirring and dispersing includes the following steps: first, mixing and stirring the slurry for 1-3 minutes using a vacuum homogenizer at 1000-3000 rpm, and then grinding the slurry for 10-60 minutes using a three-roll mill at 100-300 rpm, so as to make the slurry more uniformly dispersed.

[0062] This invention further eliminates particle aggregation and ensures the long-term stability of the slurry by optimizing the mixing and dispersion parameters. While planetary ball mills offer uniform mixing, they are time-consuming; vacuum homogenizers offer high speeds but short mixing times, leaving some agglomerated particles undispersed after mixing. Therefore, this invention, by combining it with a three-roll mill, achieves better slurry dispersion.

[0063] A method for manufacturing a copper structure includes the following steps:

[0064] S1: The photocurable 3D printing copper paste is photocured and 3D printed to form a green body;

[0065] S2: Degreasing the green body;

[0066] S3: The degreased part is sintered at high temperature to obtain a metallic copper structure.

[0067] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0068] This invention achieves efficient removal of organic components and densification of the copper structure by combining degreasing and sintering processes.

[0069] According to one embodiment of the present invention, in step S1, the parameters of the photopolymerization 3D printing include:

[0070] The wavelength of ultraviolet light is 385–405 nm;

[0071] And / or, light intensity of 20–200 mW / cm 2 ;

[0072] And / or, the exposure time is 5 to 120 seconds.

[0073] This invention ensures interlayer bonding strength and minimum feature size (as low as 100 μm) by precisely controlling the photocuring parameters.

[0074] According to one embodiment of the present invention, the degreasing treatment in step S2 includes the following steps:

[0075] In a vacuum or inert atmosphere, the green compact is heated to 500-600°C at a rate of 0.1-2°C / min and held at that temperature for 2-8 hours.

[0076] Subsequently, in an oxygen-containing atmosphere, the temperature is increased to 700–800℃ at a rate of 0.5–5℃ / min and held for 2–6 hours;

[0077] Cool to 200-220°C at a rate of 1-3°C / min, then cool to room temperature in the furnace to obtain the degreased part.

[0078] During the degreasing process, this invention avoids organic residue, reduces copper oxidation, and ensures the integrity of the structure after sintering by degreasing in stages.

[0079] According to one embodiment of the present invention, in step S3, the parameters of the high-temperature sintering include:

[0080] A mixed atmosphere of hydrogen and argon;

[0081] And / or, the heating rate of the high-temperature sintering is 0.2 to 5 °C / min;

[0082] And / or, the high-temperature sintering temperature is 950–1060°C;

[0083] And / or, the high-temperature sintering time is 2 to 10 hours.

[0084] During the high-temperature sintering stage, this invention uses high-temperature hydrogen reduction to eliminate oxides and promote diffusion between copper particles, thereby improving the conductivity and mechanical strength of the final product.

[0085] According to one embodiment of the present invention, the hydrogen volume ratio in the hydrogen and argon mixture is 2% to 20%.

[0086] According to one embodiment of the present invention, the high-temperature sintering in step S3 includes the following steps:

[0087] In a mixture of hydrogen and argon, the temperature is increased to 500–800°C at a rate of 0.2–5°C / min and held for 2–10 hours; then increased to 950–1060°C at a rate of 1–5°C / min and held for 2–10 hours; finally, the temperature is cooled to 200°C at a rate of 1–3°C / min and then cooled to room temperature in the furnace.

[0088] A copper structure prepared according to the method is disclosed, wherein the minimum feature size of the copper structure is 100 μm. This invention achieves the fabrication of high-precision complex structures through synergistic optimization of the slurry and process, meeting the industrial demands for micro-sized parts.

[0089] Another aspect of the invention relates to the application of the copper paste in the manufacture of electronic devices, aerospace components, or biomedical implants.

[0090] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the discovery. Attached Figure Description

[0091] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0092] Figure 1This is a photograph of the green blank from Example 1.

[0093] Figure 2 This is a physical image of the precision copper structure printed in Example 1.

[0094] Figure 3 This is a physical image of the copper structure printed in Comparative Example 1.

[0095] Figure 4 This is a physical image of the copper paste used in Comparative Example 2.

[0096] Figure 5 This is a physical image of the copper paste used in Comparative Example 3.

[0097] Figure 6 This is a physical image of the copper paste used in Comparative Example 7.

[0098] Figure 7 This is a physical image of the copper structure printed in Comparative Example 9. Detailed Implementation

[0099] The terms "preferred," "more preferred," etc., used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0100] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0101] 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 the present invention.

[0102] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0103] In the examples and comparative examples, the aliphatic polyurethane acrylate was Allnex EBECRYL 264.

[0104] Example 1

[0105] This example provides a photocurable 3D printing copper paste, its preparation method, and a copper structure is prepared using the aforementioned photocurable 3D printing copper paste.

[0106] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0107] Aliphatic polyurethane acrylate, 9 parts;

[0108] Trimethylolpropane triacrylate, 6 parts;

[0109] Copper powder, 85 parts;

[0110] KOS110 dispersant, 1 part;

[0111] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0112] Hydroquinone thermal polymerization inhibitor, 0.008 parts;

[0113] Benzotriazole copper inhibitor, 0.1 parts;

[0114] Of the copper powders mentioned above, 15% are copper powders with a particle size of 1μm, 15% are copper powders with a particle size of 5μm, and 70% are copper powders with a particle size of 20μm.

[0115] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0116] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, hydroquinone thermal inhibitor, and benzotriazole copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground and stirred evenly using a three-roll mill to obtain a copper paste suitable for photopolymerization 3D printing.

[0117] Testing showed that the photocurable 3D printing copper paste from Example 1 exhibited good stability, showing no significant sedimentation or spontaneous curing after 60 days at room temperature. After 180 days of storage at 4°C in the dark, no significant sedimentation or self-curing was observed.

[0118] A method for manufacturing a copper structure includes the following steps:

[0119] S1: Use the above-mentioned photopolymerizable 3D printing copper paste for photopolymerization 3D printing to form a green body. The 3D printing parameters are: ultraviolet light wavelength of 405nm, and exposure light intensity of 120mW / cm². 2 The time was 30 seconds, and the printing layer thickness was set to 0.05mm.

[0120] S2: Place the green sample in a tube furnace, introduce an argon atmosphere, and heat it to 550℃ at a rate of 0.25℃ / min and hold for 4 hours; then switch the atmosphere to an oxygen / nitrogen mixture (oxygen content 20%), heat it to 800℃ at a rate of 1℃ / min and hold for 2 hours; finally, cool it to 200℃ at a rate of 2℃ / min, and then cool it to room temperature with the furnace to complete the degreasing.

[0121] S3: Place the degreased sample in a tube furnace, introduce a hydrogen / argon mixture (hydrogen content 5%), heat to 550℃ at a rate of 1℃ / min, hold for 8h; then heat to 1050℃ at a rate of 3℃ / min, hold for 2h; finally cool to 200℃ at a rate of 2℃ / min, and then cool to room temperature with the furnace to obtain a precision metallic copper structure.

[0122] The actual picture of the green body in Example 1 is shown below. Figure 1 As shown, a physical image of the precision metal copper structure is as follows: Figure 2 As shown. From Figure 2 It can be seen that the precision copper structure prepared in Example 1 has very high forming accuracy, with a wall thickness of about 200 μm and no obvious defects.

[0123] Example 2

[0124] This example provides a photocurable 3D printing copper paste, its preparation method, and a copper structure is prepared using the aforementioned photocurable 3D printing copper paste.

[0125] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0126] Aliphatic polyurethane diacrylate, 8 parts;

[0127] 10 parts of pentaerythritol tetraacrylate ethoxylate;

[0128] Copper powder, 82 parts;

[0129] BYK111 dispersant, 1 part;

[0130] Diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 1.5 parts;

[0131] 0.01 parts of tert-butylcatechol and phenothiazine thermal polymerization inhibitor;

[0132] Triphenyl phosphate copper inhibitor, 0.2 parts;

[0133] Of the copper powders mentioned above, 1μm copper powder accounts for 20% by mass, 5μm copper powder accounts for 25% by mass, and 20μm copper powder accounts for 55% by mass.

[0134] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0135] Aliphatic polyurethane diacrylate, pentaerythritol tetraacrylate ethoxylate, BYK111 dispersant, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, tert-butylcatechol and phenothiazine thermal inhibitor, and triphenyl phosphate copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a ball mill jar and mixed with a ball mill at 360 rpm for 4 hours to obtain photocurable 3D printing copper paste.

[0136] Testing showed that the photocurable 3D printing copper paste prepared in Example 2 exhibited good stability, with no significant sedimentation or spontaneous curing after 60 days at room temperature. After 180 days of storage at 4°C in the dark, no significant sedimentation or self-curing was observed.

[0137] A method for manufacturing a copper structure includes the following steps:

[0138] S1: Use the above-mentioned photopolymerizable 3D printing copper paste for photopolymerization 3D printing to form a green body. The 3D printing parameters are: ultraviolet light wavelength of 405nm, and exposure light intensity of 150mW / cm². 2 The time was 40 seconds, and the printing layer thickness was set to 0.04mm.

[0139] S2: Place the green sample in a tube furnace, introduce an argon atmosphere, and heat it to 550℃ at a rate of 0.25℃ / min and hold for 4 hours; then switch the atmosphere to an oxygen / nitrogen mixture (oxygen content 20%), heat it to 800℃ at a rate of 1℃ / min and hold for 2 hours; finally, cool it to 200℃ at a rate of 2℃ / min, and then cool it to room temperature with the furnace to complete the degreasing.

[0140] S3: Place the degreased sample in a tube furnace, introduce a hydrogen / argon mixture (hydrogen content 10%), heat to 550℃ at a rate of 1℃ / min, and hold for 8 hours; then heat to 1050℃ at a rate of 3℃ / min and hold for 2 hours; finally cool to 200℃ at a rate of 2℃ / min, and then cool to room temperature with the furnace to obtain a precision metallic copper structure.

[0141] Example 3

[0142] This example provides a photocurable 3D printing copper paste, its preparation method, and a copper structure is prepared using the aforementioned photocurable 3D printing copper paste.

[0143] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0144] Aliphatic polyurethane acrylate, 7 parts;

[0145] Trimethylolpropane triacrylate, 7 parts;

[0146] Dipentaerythritol hexaacrylate, 1 part;

[0147] Copper powder, 85 parts;

[0148] KOS110 dispersant, 1 part;

[0149] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0150] Hydroquinone and diphenylamine thermal inhibitor, 0.01 parts;

[0151] Benzotriazole copper inhibitor, 0.1 parts;

[0152] Of the copper powders mentioned above, 1μm copper powder accounts for 15% by mass, 5μm copper powder accounts for 15% by mass, and 20μm copper powder accounts for 70% by mass.

[0153] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0154] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, hydroquinone and diphenylamine thermal inhibitors, and benzotriazole copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a ball mill jar and mixed with a ball mill at 360 rpm for 4 hours to obtain photocurable 3D printing copper paste.

[0155] Testing showed that the photocurable 3D printing copper paste prepared in Example 3 exhibited good stability, showing no significant sedimentation or spontaneous curing after 60 days at room temperature. After 180 days of storage at 4°C in the dark, no significant sedimentation or self-curing was observed.

[0156] A method for manufacturing a copper structure includes the following steps:

[0157] S1: Use the above-mentioned photopolymerizable 3D printing copper paste for photopolymerization 3D printing to form a green body. The 3D printing parameters are: ultraviolet light wavelength of 405nm, and exposure light intensity of 120mW / cm². 2 The time was 30 seconds, and the printing layer thickness was set to 0.05mm.

[0158] S2: Place the green sample in a tube furnace, introduce an argon atmosphere, and heat it to 550℃ at a rate of 0.25℃ / min and hold for 4 hours; then switch the atmosphere to an oxygen / nitrogen mixture (oxygen content 20%), heat it to 800℃ at a rate of 1℃ / min and hold for 2 hours; finally, cool it to 200℃ at a rate of 2℃ / min, and then cool it to room temperature with the furnace to complete the degreasing.

[0159] S3: Place the degreased sample in a tube furnace, introduce a hydrogen / argon mixture (hydrogen content 15%), heat to 550℃ at a rate of 1℃ / min, hold for 8 hours; then heat to 1050℃ at a rate of 3℃ / min, hold for 2 hours; finally cool to 200℃ at a rate of 2℃ / min, and then cool to room temperature with the furnace to obtain a precision metallic copper structure.

[0160] Example 4

[0161] This example provides a photocurable 3D printing copper paste, its preparation method, and a copper structure is prepared using the aforementioned photocurable 3D printing copper paste.

[0162] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0163] Aliphatic polyurethane acrylate, 7 parts;

[0164] Trimethylolpropane triacrylate, 7 parts;

[0165] Dipentaerythritol hexaacrylate, 1 part;

[0166] Copper powder, 85 parts;

[0167] KOS110 dispersant, 1 part;

[0168] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0169] Hydroquinone and diphenylamine thermal inhibitor, 0.01 parts;

[0170] Benzotriazole copper inhibitor, 0.1 parts;

[0171] Of the copper powders mentioned above, 1μm copper powder accounts for 40% by mass, 5μm copper powder accounts for 30% by mass, and 20μm copper powder accounts for 30% by mass.

[0172] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0173] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, hydroquinone and diphenylamine thermal inhibitors, and benzotriazole copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a ball mill jar and mixed with a ball mill at 360 rpm for 4 hours to obtain photocurable 3D printing copper paste.

[0174] Testing showed that the photocurable 3D printing copper paste prepared in Example 4 exhibited good stability, showing no significant sedimentation or spontaneous curing after 60 days at room temperature. After 180 days of storage at 4°C in the dark, no significant sedimentation or self-curing was observed.

[0175] A method for manufacturing a copper structure includes the following steps:

[0176] S1: Use the above-mentioned photopolymerizable 3D printing copper paste for photopolymerization 3D printing to form a green body. The 3D printing parameters are: ultraviolet light wavelength of 405nm, and exposure light intensity of 150mW / cm². 2 The time was 100 seconds, and the printing layer thickness was set to 0.03mm.

[0177] S2: Place the green sample in a tube furnace, introduce an argon atmosphere, and heat it to 550℃ at a rate of 0.25℃ / min and hold for 4 hours; then switch the atmosphere to an oxygen / nitrogen mixture (oxygen content 20%), heat it to 800℃ at a rate of 1℃ / min and hold for 2 hours; finally, cool it to 200℃ at a rate of 2℃ / min, and then cool it to room temperature with the furnace to complete the degreasing.

[0178] S3: Place the degreased sample in a tube furnace, introduce a hydrogen / argon mixture (hydrogen content 15%), heat to 550℃ at a rate of 1℃ / min, hold for 8 hours; then heat to 1050℃ at a rate of 3℃ / min, hold for 2 hours; finally cool to 200℃ at a rate of 2℃ / min, and then cool to room temperature with the furnace to obtain a precision metallic copper structure.

[0179] Comparative Example 1

[0180] The difference between Comparative Example 1 and Example 1 is that no thermal inhibitor and anti-copper agent components were added to the copper paste of Comparative Example 1.

[0181] Specifically:

[0182] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0183] Aliphatic polyurethane acrylate, 8 parts;

[0184] Trimethylolpropane triacrylate, 7 parts;

[0185] Copper powder, 85 parts;

[0186] KOS110 dispersant, 1 part;

[0187] 0.8 parts of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator;

[0188] Of the copper powders mentioned above, 1μm copper powder accounts for 15% by mass, 5μm copper powder accounts for 15% by mass, and 20μm copper powder accounts for 70% by mass.

[0189] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0190] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, KOS110 dispersant, and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground and stirred evenly using a three-roll mill to obtain a copper paste suitable for photopolymerization 3D printing.

[0191] The copper paste in Comparative Example 1, due to the lack of heating inhibitors and copper-resistant agents, has poor printing accuracy and is prone to spontaneous curing during use.

[0192] A method for manufacturing a copper structure includes the following steps:

[0193] S1: Use the above-mentioned photopolymerizable 3D printing copper paste for photopolymerization 3D printing to form a green body. The 3D printing parameters are: ultraviolet light wavelength of 405nm, and exposure light intensity of 120mW / cm². 2 The time was 30 seconds, and the printing layer thickness was set to 0.05mm.

[0194] S2: Place the green sample in a tube furnace, introduce an argon atmosphere, and heat it to 550℃ at a rate of 0.25℃ / min and hold for 4 hours; then switch the atmosphere to an oxygen / nitrogen mixture (oxygen content 20%), heat it to 800℃ at a rate of 1℃ / min and hold for 2 hours; finally, cool it to 200℃ at a rate of 2℃ / min, and then cool it to room temperature with the furnace to complete the degreasing.

[0195] S3: Place the degreased sample in a tube furnace, introduce a hydrogen / argon mixture (5% hydrogen content), heat to 550℃ at a rate of 1℃ / min, hold for 8 hours; then heat to 1050℃ at a rate of 3℃ / min, hold for 2 hours; finally cool to 200℃ at a rate of 2℃ / min, and then cool to room temperature with the furnace to obtain a copper structure.

[0196] A physical image of the precision copper structure printed in Comparative Example 1 is shown below. Figure 3 As shown, from Figure 3 It can be seen that the printing precision of this slurry is poor. During the printing process, the exothermic photocuring reaction caused over-curing of the structure, resulting in the pores in the printed structure being blocked. In addition, the slurry did not show obvious settling during use, but it began to self-cur after 3 days, making it impossible to continue printing.

[0197] Comparative Example 2

[0198] The difference between Comparative Example 2 and Example 1 is that the main component of the organic slurry system in Comparative Example 2 is bisphenol A epoxy acrylate.

[0199] Specifically:

[0200] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0201] Bisphenol A epoxy acrylate, 9 parts;

[0202] Trimethylolpropane triacrylate, 6 parts;

[0203] Copper powder, 85 parts;

[0204] KOS110 dispersant, 1 part;

[0205] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0206] Hydroquinone thermal polymerization inhibitor, 0.008 parts;

[0207] Benzotriazole copper inhibitor, 0.1 parts;

[0208] Of the copper powders mentioned above, 1μm copper powder accounts for 15% by mass, 5μm copper powder accounts for 15% by mass, and 20μm copper powder accounts for 70% by mass.

[0209] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0210] Bisphenol A epoxy acrylate, trimethylolpropane triacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, hydroquinone thermal inhibitor and benzotriazole copper inhibitor were stirred until completely dissolved, and then copper powder was added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground with a three-roll mill and stirred evenly to obtain a copper paste that can be used for photopolymerization 3D printing.

[0211] A physical image of the copper paste from Comparative Example 2 is shown below. Figure 4 As shown, from Figure 4As can be seen, the slurry in Comparative Example 2 has poor stability and is prone to self-curing. It begins to form a gel after 5 days at room temperature and is completely cured after 7 days.

[0212] Comparative Example 3

[0213] The difference between Comparative Example 3 and Example 1 is that the copper paste of Comparative Example 3 does not contain aliphatic polyurethane acrylate.

[0214] Specifically:

[0215] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0216] Trimethylolpropane triacrylate, 15 parts;

[0217] Copper powder, 85 parts;

[0218] KOS110 dispersant, 1 part;

[0219] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0220] Hydroquinone thermal polymerization inhibitor, 0.008 parts;

[0221] Benzotriazole copper inhibitor, 0.1 parts;

[0222] Of the copper powders mentioned above, 1μm copper powder accounts for 15% by mass, 5μm copper powder accounts for 15% by mass, and 20μm copper powder accounts for 70% by mass.

[0223] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0224] Trimethylolpropane triacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, hydroquinone thermal inhibitor, and benzotriazole copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground and stirred evenly to obtain a copper paste suitable for photopolymerization 3D printing.

[0225] A physical image of the copper paste prepared in Comparative Example 3 is shown below. Figure 5 As shown, from Figure 5 It is known that the slurry has poor stability and will show significant sedimentation after being left at room temperature for 2 days.

[0226] Comparative Example 4

[0227] The difference between Comparative Example 4 and Example 1 is that no copper inhibitor was added to the copper paste of Comparative Example 4.

[0228] Specifically:

[0229] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0230] Aliphatic polyurethane acrylate, 9 parts;

[0231] Trimethylolpropane triacrylate, 6 parts;

[0232] Copper powder, 85 parts;

[0233] KOS110 dispersant, 1 part;

[0234] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0235] Hydroquinone thermal polymerization inhibitor, 0.008 parts;

[0236] Of the copper powders mentioned above, 1μm copper powder accounts for 15% by mass, 5μm copper powder accounts for 15% by mass, and 20μm copper powder accounts for 70% by mass.

[0237] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0238] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, and hydroquinone thermal inhibitor were stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground with a three-roll mill and stirred evenly to obtain a copper paste suitable for photopolymerization 3D printing.

[0239] Since no copper inhibitor was added, the copper paste in Comparative Example 4 began to self-cur after being left at room temperature for 7 days.

[0240] Comparative Example 5

[0241] The difference between Comparative Example 5 and Example 1 is that the copper powder in Comparative Example 5 has a particle size of only 1 μm.

[0242] Specifically:

[0243] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0244] Aliphatic polyurethane acrylate, 9 parts;

[0245] Trimethylolpropane triacrylate, 6 parts;

[0246] Copper powder, 85 parts;

[0247] KOS110 dispersant, 1 part;

[0248] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0249] Hydroquinone thermal polymerization inhibitor, 0.008 parts;

[0250] Benzotriazole copper inhibitor, 0.1 parts;

[0251] The particle size of the copper powder mentioned above is 1 μm.

[0252] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0253] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, hydroquinone thermal inhibitor, and benzotriazole copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground and stirred evenly using a three-roll mill to obtain a copper paste suitable for photopolymerization 3D printing.

[0254] Compared with Example 1, the copper powder in Comparative Example 5 was not particle size-graded and all of it was copper powder with a small particle size of 1μm. As a result, the photoreactivity of the copper paste in Comparative Example 5 was very poor, and it was basically impossible to photocur and form.

[0255] Comparative Example 6

[0256] The difference between Comparative Example 6 and Example 1 is that the copper powder in Comparative Example 6 has a particle size of only 20 μm.

[0257] Specifically:

[0258] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0259] Aliphatic polyurethane acrylate, 9 parts;

[0260] Trimethylolpropane triacrylate, 6 parts;

[0261] Copper powder, 85 parts;

[0262] KOS110 dispersant, 1 part;

[0263] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0264] Hydroquinone thermal polymerization inhibitor, 0.008 parts;

[0265] Benzotriazole copper inhibitor, 0.1 parts;

[0266] The particle size of the copper powder mentioned above is 20 μm.

[0267] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0268] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, hydroquinone thermal inhibitor, and benzotriazole copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground and stirred evenly using a three-roll mill to obtain a copper paste suitable for photopolymerization 3D printing.

[0269] Compared with Example 1, the copper powder in Comparative Example 6 was not particle size-graded and all of it was copper powder with a large particle size of 20μm. As a result, the copper slurry in Comparative Example 6 had poor stability and was very easy to settle. Significant settling occurred after being placed at room temperature for 2 days.

[0270] Comparative Example 7

[0271] The difference between Comparative Example 7 and Example 1 is that the heat inhibitor in Comparative Example 7 is ferric chloride, and the copper inhibitor is thioglycerol.

[0272] Specifically:

[0273] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0274] Aliphatic polyurethane acrylate, 9 parts;

[0275] Trimethylolpropane triacrylate, 6 parts;

[0276] Copper powder, 85 parts;

[0277] KOS110 dispersant, 1 part;

[0278] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0279] Ferric chloride heat inhibitor, 0.008 parts;

[0280] Thioglycerin copper inhibitor, 0.1 parts;

[0281] Of the copper powders mentioned above, 1μm copper powder accounts for 15% by mass, 5μm copper powder accounts for 15% by mass, and 20μm copper powder accounts for 70% by mass.

[0282] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0283] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, ferric chloride thermal inhibitor, and thioglycerol copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground and stirred evenly using a three-roll mill to obtain a copper paste suitable for photopolymerization 3D printing.

[0284] A physical image of the copper paste prepared in Comparative Example 7 is shown below. Figure 6 As shown, from Figure 6 It can be seen that the copper paste in Comparative Example 7 has poor stability and self-cures after being left at room temperature for 3 days, making it unsuitable for long-term printing.

[0285] Comparative Example 8

[0286] The difference between Comparative Example 8 and Example 1 is that the heat inhibitor in Comparative Example 7 is sodium sulfide, and the copper inhibitor is thioglycerol.

[0287] Specifically:

[0288] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0289] Aliphatic polyurethane acrylate, 9 parts;

[0290] Trimethylolpropane triacrylate, 6 parts;

[0291] Copper powder, 85 parts;

[0292] KOS110 dispersant, 1 part;

[0293] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0294] Sodium sulfide heat inhibitor, 0.008 parts;

[0295] Thioglycerin copper inhibitor, 0.1 parts;

[0296] Of the copper powders mentioned above, 1μm copper powder accounts for 15% by mass, 5μm copper powder accounts for 15% by mass, and 20μm copper powder accounts for 70% by mass.

[0297] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0298] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, sodium sulfide thermal inhibitor, and thioglycerol copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground and stirred evenly using a three-roll mill to obtain a copper paste suitable for photopolymerization 3D printing.

[0299] The copper paste prepared in Comparative Example 8 has poor stability and self-cures after being left at room temperature for 3 days, making it unsuitable for long-term printing.

[0300] Comparative Example 9

[0301] The difference between Comparative Example 9 and Example 1 is that in Comparative Example 9, the degreasing and sintering heating rates are faster during photopolymerization 3D printing, reaching the target temperature at a rate of 10°C / min.

[0302] Specifically:

[0303] A photopolymerizable 3D printing copper paste comprises the following components in parts by weight:

[0304] Aliphatic polyurethane acrylate, 9 parts;

[0305] Trimethylolpropane triacrylate, 6 parts;

[0306] Copper powder, 85 parts;

[0307] KOS110 dispersant, 1 part;

[0308] Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, 0.8 parts;

[0309] Hydroquinone thermal polymerization inhibitor, 0.008 parts;

[0310] Benzotriazole copper inhibitor, 0.1 parts;

[0311] Of the copper powders mentioned above, 15% are copper powders with a particle size of 1μm, 15% are copper powders with a particle size of 5μm, and 70% are copper powders with a particle size of 20μm.

[0312] A method for preparing the photopolymerizable 3D printing copper paste includes the following steps:

[0313] Aliphatic polyurethane acrylate, trimethylolpropane triacrylate, KOS110 dispersant, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide photoinitiator, hydroquinone thermal inhibitor, and benzotriazole copper inhibitor were mixed and stirred until completely dissolved. Copper powder was then added to obtain a mixture. The mixture was placed in a vacuum homogenizer container and homogenized at 2000 rpm for 2 minutes. The mixture was then ground and stirred evenly using a three-roll mill to obtain a copper paste suitable for photopolymerization 3D printing.

[0314] A method for manufacturing a copper structure includes the following steps:

[0315] S1: Use the above-mentioned photopolymerizable 3D printing copper paste for photopolymerization 3D printing to form a green body. The 3D printing parameters are: ultraviolet light wavelength of 405nm, and exposure light intensity of 120mW / cm². 2 The time was 30 seconds, and the printing layer thickness was set to 0.05mm.

[0316] S2: Place the green sample in a tube furnace, introduce an argon atmosphere, and heat it to 550℃ at a rate of 10℃ / min and hold for 4 hours; then switch the atmosphere to an oxygen / nitrogen mixture (oxygen content 20%), heat it to 800℃ at a rate of 10℃ / min and hold for 2 hours; finally, cool it to 200℃ at a rate of 2℃ / min, and then cool it to room temperature with the furnace to complete the degreasing.

[0317] S3: Place the degreased sample in a tube furnace, introduce a hydrogen / argon mixture (5% hydrogen content), heat to 550℃ at a rate of 10℃ / min, and hold for 8 hours; then heat to 1050℃ at a rate of 10℃ / min and hold for 2 hours; finally cool to 200℃ at a rate of 2℃ / min, and then cool to room temperature with the furnace to obtain a copper structure.

[0318] A physical diagram of the copper structure in Comparative Example 9 is shown below. Figure 7 As shown, from Figure 7 It can be seen that the faster the sintering heating rate, the more obvious defects such as cracks, delamination, and deformation appear in the copper structure of Comparative Example 9.

[0319] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A photopolymerizable 3D printing copper paste, characterized in that: Includes the following components: Polyurethane acrylate; Copper powder; Photoinitiator; Heat-resistant polymerization inhibitor; Copper inhibitor; The copper inhibitor is selected from at least one of benzotriazole, benzotriazole derivatives, 3-mercaptopropionic acid, triphenyl phosphate, triphenyl phosphite, and trimethyl phosphate.

2. The photopolymerizable 3D printing copper paste according to claim 1, characterized in that: The photopolymerizable 3D printing copper paste comprises the following components in parts by weight: Polyurethane acrylate, 2-30 parts; Copper powder, 60-94 parts; Photoinitiator, 0.02–5 parts; Heat-inhibiting polymerization agent, 0.002–0.5 parts; Copper inhibitor, 0.005 to 2 parts.

3. The photopolymerizable 3D printing copper paste according to claim 1, characterized in that: The copper powder is composed of copper particles with average particle sizes of 0.3–1 μm, 3–5 μm, and 10–20 μm.

4. The photopolymerizable 3D printing copper paste according to claim 1, characterized in that: The polyurethane acrylate includes at least one of aromatic polyurethane acrylate, aliphatic polyurethane acrylate, aliphatic polyurethane diacrylate, and aliphatic polyurethane hexaacrylate.

5. The photopolymerizable 3D printing copper paste according to claim 1, characterized in that: The heat-inhibiting polymerization agent is at least one selected from hydroquinone, hydroquinone monomethyl ether, diphenylamine, diphenylamine sulfide, tert-butylcatechol, phenothiazine, and 2,2,6,6-tetramethylpiperidine oxide.

6. A method for preparing the photopolymerizable 3D printing copper paste as described in any one of claims 1 to 5, characterized in that: Includes the following steps: The polyurethane acrylate, photoinitiator, thermal inhibitor and copper inhibitor are mixed and then the copper powder is added and stirred to disperse, thus obtaining the photocurable 3D printing copper paste.

7. A method for manufacturing a copper structure, characterized in that: Includes the following steps: S1: Photopolymer 3D printing is performed on the photopolymer 3D printing copper paste as described in any one of claims 1 to 5 to form a green body; S2: Degreasing the green body; S3: The degreased part is sintered at high temperature to obtain a metallic copper structure.

8. The photopolymerization 3D printing method according to claim 7, characterized in that: In step S3, the parameters for high-temperature sintering include: A mixed atmosphere of hydrogen and argon; And / or, the heating rate of the high-temperature sintering is 0.2 to 5 °C / min; And / or, the high-temperature sintering temperature is 950–1060°C; And / or, the high-temperature sintering time is 2 to 10 hours.

9. A metallic copper structure prepared by the method of claim 7, characterized in that, The minimum feature size of the copper structure is 100 μm.

10. The application of the copper paste as described in claim 9 in the manufacture of electronic devices, aerospace components or biomedical implants.

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