A method for inkjet printing of a ceramic membrane surface metal ink

Abstract

The present application relates to a kind of ceramic membrane surface metal inkjet printing method, it includes the following steps: S1.wet film preparation, S2. initial heat drying setting, S3. high-temperature sintering forming and S4. high-temperature rapid reduction.The present application has the advantages that, using inkjet printing method first forms wet film layer on the surface of ceramic flat plate membrane, then sequentially through initial heat drying setting, high-temperature sintering forming and high-temperature rapid reduction step on the surface of ceramic flat plate membrane Forming the pore-rich conductive film with firm combination, good conductivity and filtering function, inert gas is continuously passed into the inner cavity of ceramic flat plate membrane during preparation, both avoid metal ink to block the original pore of ceramic membrane as far as possible, and ensure that pore is formed on the sprayed ink layer when gas is emitted and carry out decomposition material during sintering and timely transfer;The present application has the characteristics of simple method, easy operation and low material cost, and it is functionalized on the surface of finished ceramic membrane, without adjusting the original preparation process and equipment of ceramic membrane, easy to use.

Description

Technical Field

[0001] This invention relates to the field of conductive functionalization of ceramic film surfaces, and more specifically to a method for inkjet printing of metallic inks on ceramic film surfaces. Background Technology

[0002] Conductive ceramic membranes are used in water treatment. On the one hand, they can filter impurities and pollutants; on the other hand, when energized, they can effectively remove organic matter and colloids that are difficult to remove by filtration alone, and significantly reduce pollutant adhesion to the membrane. Existing conductive ceramic membranes generally involve doping a conductive material into a ceramic slurry, followed by sintering to form the conductive membrane. The drawbacks are: the conductive material must be uniformly dispersed throughout the ceramic membrane, resulting in a large amount of conductive material and high cost; and because the composition of the ceramic slurry is altered, the process parameters and equipment requirements change, rendering existing processes and equipment unusable, leading to high investment costs for process and equipment improvements.

[0003] Forming a conductive film on the surface of a ceramic membrane using metallic ink is an effective method to endow the ceramic membrane with conductivity, enabling it to perform both filtration and electrochemical removal of contaminants. However, conventional methods for forming a conductive film on the ceramic membrane surface with metallic ink can adversely affect the membrane's filtration function. Therefore, it is necessary to research new inkjet printing methods to ensure the formation of a conductive layer with good conductivity on the ceramic membrane surface while essentially preserving the original filtration performance of the ceramic membrane. Summary of the Invention

[0004] This invention provides a method for inkjet printing of metallic ink on the surface of a ceramic membrane, aiming to overcome the shortcomings of the prior art and ensure that the metallic ink can form a conductive layer with good conductivity on the surface of the ceramic membrane while basically retaining the original filtration performance of the ceramic membrane.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A method for inkjet printing of metallic ink on the surface of a ceramic film, comprising the following steps:

[0006] S1. Wet film preparation: Using an inkjet printing device, metallic ink is used to print inkjet print on both sides of the ceramic flat film to form a wet film layer.

[0007] S2. Initial heat drying and shaping: Place the ceramic flat sheet membrane in a sealed chamber, connect the inlets at both ends of the ceramic flat sheet membrane to the inert gas pipeline, continuously introduce inert gas, maintain the gas pressure inside the ceramic flat sheet membrane at 0.15-0.35MPa, slowly raise the temperature to 190℃, and continue drying for 3-5 hours.

[0008] S3. High-temperature sintering and molding: After drying, increase the gas pressure inside the ceramic flat plate membrane to 0.5-0.7MPa and maintain it, then slowly raise the temperature to 350℃ and maintain it at 350℃ for high-temperature sintering and curing for 1.5-2.5h;

[0009] S4. High-temperature rapid reduction: After sintering and curing, the temperature is rapidly increased to 420℃, and the temperature is maintained at 420℃ for 2-3 minutes for continuous reduction. Then it is naturally cooled to 350℃, and the temperature is rapidly increased to 420℃ again for 2-3 minutes for continuous reduction. This process is repeated several times, and then the temperature is naturally cooled to room temperature to complete the metal inkjet printing of the ceramic flat film.

[0010] Based on the above technical solutions, the present invention may have the following further specific options.

[0011] Specifically, during inkjet printing in S1, the printhead of the inkjet printing device is tilted towards the plane of the ceramic flat film to spray ink.

[0012] Specifically, the thickness of the wet film layer formed by inkjet printing on the surface of the ceramic flat film in S1 is 1-5 μm.

[0013] Specifically, the inert gas in S2 is either nitrogen or argon.

[0014] Specifically, in S2 and S3, the ceramic flat sheet membrane is placed vertically inside the sealed box.

[0015] Specifically, the heating rate in S2 and S3 is controlled at 1-3℃ / min.

[0016] Specifically, the heating rate in S4 is controlled at 5-8℃ / min.

[0017] Specifically, in S4, the temperature is raised to 420℃ and reduction is repeated 3-5 times.

[0018] Specifically, the metallic ink used in S1 contains organic copper salts, organic amines, inorganic ammonium salts, graphene oxide, and polyimide ultrafine powder.

[0019] Specifically, the polyimide ultrafine powder is a thermosetting resin with an average particle size of 30-40 μm.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This invention employs inkjet printing to first form a wet film layer on the surface of a ceramic flat sheet. Then, through a series of steps including initial heat drying and shaping, high-temperature sintering, and high-temperature rapid reduction, a porous conductive film with strong adhesion, good conductivity, and filtration function is formed on the ceramic flat sheet surface. During the preparation process, inert gas is continuously passed into the inner cavity of the ceramic flat sheet, which minimizes the blockage of the original pores of the ceramic film by metallic ink, while ensuring that the released gas forms pores on the sprayed ink layer and carries away decomposed substances from sintering. The inkjet printing method provided by this invention for forming a conductive layer on the surface of a ceramic film is simple, easy to operate, and has low material costs. Furthermore, it functionalizes the surface of the finished ceramic film without requiring adjustments to the original slurry composition, molding process, or molding equipment, thus facilitating its market adoption. Attached Figure Description

[0022] Figure 1 The flowchart illustrates a method for inkjet printing of metallic inks on a ceramic film surface, as provided by this invention. Detailed Implementation

[0023] The principles and features of the present invention are described below with reference to the accompanying drawings and specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0024] like Figure 1 As shown, this invention provides a method for inkjet printing of metallic ink on the surface of a ceramic membrane, which includes sequential steps of wet film layer preparation, initial heat drying and shaping, high-temperature sintering and molding, and high-temperature rapid reduction. This method can form a porous conductive membrane with strong bonding, good conductivity, and filtration function on the surface of the ceramic flat membrane. During the preparation process, an inert gas is continuously passed into the inner cavity of the ceramic flat membrane. The continuous passage of inert gas not only avoids the metallic ink from blocking the original pores of the ceramic membrane as much as possible, but also ensures that pores are formed on the ink layer when the gas is released, protecting the copper and graphene conductive components formed under high temperature reduction from being oxidized by the air and carrying away the decomposed substances during sintering in a timely manner.

[0025] It should be noted that continuously introducing inert gas into a sealed chamber will gradually increase the internal pressure. Therefore, after initially introducing a certain amount of inert gas, the system is switched to internal circulation ventilation. The existing inert gas and the gases produced by decomposition within the chamber are used as a mixed gas source, and the pressurized circulation component continuously ventilates the ceramic membrane cavity. The gas pressure is indicated by a pressure gauge. During the preparation process, the ceramic membrane cavity is ventilated, and the gas flows outwards from the inside to the outside of the membrane surface. Although inkjet printing involves spraying ink at an angle towards the membrane surface, some ink components inevitably enter the original pores of the ceramic flat membrane. Reverse ventilation before curing allows this portion of ink to escape from the pores. Simultaneously, the gas passing through the wet membrane layer also creates pores in the wet membrane layer. Combined with the thermal decomposition of inorganic ammonium salts in the ink of the wet membrane layer, this ensures that the membrane layer after initial drying and shaping has abundant pores. Subsequently, during high-temperature sintering, the polyimide in the ink undergoes softening and melting before… During the cross-linking and curing process, reverse ventilation can prevent the softened and molten polyimide from blocking the pores. After cross-linking and curing, the pores are enriched and the shape is completely fixed. In the high-temperature rapid reduction stage, repeated intermittent high-temperature reduction treatment is adopted. At a high temperature of 420℃, the decomposition and generation of ammonia gas can accelerate the reduction of graphene oxide and copper ions. It also avoids damage to the solidified part of polyimide caused by continuous high temperature. In order to enhance the reduction and save the time of repeated high-temperature treatment in the high-temperature rapid reduction stage, a small amount of ammonia or hydrogen gas can be introduced into the sealed box during actual production.

[0026] The metallic ink used in this invention is specifically composed of soluble organic copper salt, organic amine, inorganic ammonium salt, graphene oxide, polyimide ultrafine powder, ethanol, and water. The mass ratio of inorganic ammonium salt, graphene oxide, polyimide ultrafine powder, and soluble organic copper salt is (0.05-0.08):(0.02-0.04):(0.03-0.06):1; the volume ratio of ethanol to water is 0.3-0.5:1; the amount ratio of soluble organic copper salt to water is 0.12-0.25 g:1 mL; and the molar ratio of copper ions in the soluble organic copper salt to the organic amine is 1:1-4. Specifically, the soluble organic copper salt is copper acetate; the organic amine is preferably ethylenediamine or ethanolamine; the inorganic ammonium salt is ammonium chloride; the graphene oxide is preferably single-layer graphene; and the polyimide is preferably an ultrafine powder with an average particle size of 30-40 μm, and is a thermosetting resin.

[0027] The following description is based on specific embodiments. Unless otherwise specified, all drugs used in the following embodiments are commercially available products, and all methods used are conventional methods in the art unless otherwise specified.

[0028] Example 1

[0029] A method for inkjet printing metallic inks onto a ceramic film surface, comprising the following steps:

[0030] S1. Wet film preparation: The ceramic flat film is printed on both sides using an inkjet printing device with metallic ink as raw material to form a wet film layer. The ink is sprayed at a certain angle to avoid vertical spraying. The thickness of the wet film layer is controlled to be 3-5μm.

[0031] S2. Initial heat drying and shaping: Place the ceramic flat sheet membrane vertically in a sealed chamber, connect the inlets at both ends of the ceramic flat sheet membrane to nitrogen pipelines, continuously introduce nitrogen to maintain the gas pressure inside the ceramic flat sheet membrane at 0.30-0.35MPa, slowly raise the temperature to 190℃, and continue drying for 5 hours.

[0032] S3. High-temperature sintering and molding: After drying, increase the gas pressure inside the ceramic flat film to 0.7MPa and maintain it, then slowly raise the temperature to 350℃ at a rate of 1℃ / min, and maintain the high-temperature sintering and curing at 350℃ for 2.5h.

[0033] S4. High-temperature rapid reduction: After sintering and curing, the temperature is rapidly increased to 420℃ at a rate of 8℃ / min. The temperature is maintained at 420℃ for 2-3 minutes for continuous reduction. Then the temperature is naturally cooled to 350℃. The temperature is then rapidly increased to 420℃ again for 2-3 minutes for continuous reduction. This process is repeated 5 times. Finally, the temperature is naturally cooled to room temperature to complete the metal inkjet printing on the ceramic flat film.

[0034] Example 2

[0035] A method for inkjet printing metallic inks onto a ceramic film surface, comprising the following steps:

[0036] S1. Wet film preparation: The ceramic flat film is printed on both sides using an inkjet printing device with metallic ink as raw material to form a wet film layer. The ink is sprayed at a certain angle to avoid vertical spraying. The thickness of the wet film layer is controlled to be 1-3μm.

[0037] S2. Initial heat drying and shaping: Place the ceramic flat sheet membrane vertically in a sealed chamber, connect the inlets at both ends of the ceramic flat sheet membrane to nitrogen pipelines, continuously introduce nitrogen to maintain the gas pressure inside the ceramic flat sheet membrane at 0.15-0.25MPa, slowly raise the temperature to 190℃, and continue drying for 3 hours.

[0038] S3. High-temperature sintering and molding: After drying, increase the gas pressure inside the ceramic flat film to 0.5MPa and maintain it, then slowly raise the temperature to 350℃ at a rate of 3℃ / min, and maintain the high-temperature sintering and curing at 350℃ for 1.5h.

[0039] S4. High-temperature rapid reduction: After sintering and curing, the temperature is rapidly increased to 420℃ at a rate of 5℃ / min. The temperature is maintained at 420℃ for 2-3 minutes for continuous reduction. Then the temperature is naturally cooled to 350℃. The temperature is then rapidly increased to 420℃ again for 2-3 minutes for continuous reduction. This process is repeated 3 times. Finally, the temperature is naturally cooled to room temperature to complete the metal inkjet printing on the ceramic flat film.

[0040] Example 3

[0041] A method for inkjet printing metallic inks onto a ceramic film surface, comprising the following steps:

[0042] S1. Wet film preparation: The ceramic flat film is printed on both sides using an inkjet printing device with metallic ink as raw material to form a wet film layer. The ink is sprayed at a certain angle to avoid vertical spraying. The thickness of the wet film layer is controlled to be 2-4μm.

[0043] S2. Initial heat drying and shaping: Place the ceramic flat sheet membrane vertically in a sealed chamber, connect the inlets at both ends of the ceramic flat sheet membrane to nitrogen pipelines, continuously introduce nitrogen to maintain the gas pressure inside the ceramic flat sheet membrane at 0.2-0.3MPa, slowly raise the temperature to 190℃, and continue drying for 4 hours.

[0044] S3. High-temperature sintering and molding: After drying, increase the gas pressure inside the ceramic flat film to 0.6MPa and maintain it, then slowly raise the temperature to 350℃ at a rate of 2℃ / min, and maintain the high-temperature sintering and curing at 350℃ for 2 hours.

[0045] S4. High-temperature rapid reduction: After sintering and curing, the temperature is rapidly increased to 420℃ at a rate of 6℃ / min. The temperature is maintained at 420℃ for 2-3 minutes for continuous reduction. Then the temperature is naturally cooled to 350℃. The temperature is then rapidly increased to 420℃ again for 2-3 minutes for continuous reduction. This process is repeated 4 times. Finally, the temperature is naturally cooled to room temperature to complete the metal inkjet printing on the ceramic flat film.

[0046] Upon inspection, it was found that after undergoing the inkjet printing process described above, the ceramic flat sheet membranes in all embodiments formed a firmly bonded and highly conductive layer on their upper surface. Water treatment tests were conducted by installing the prepared ceramic flat sheet membranes onto ceramic membrane filters. It was found that compared to the untreated membranes, the filter using the ceramic flat sheet membrane of this invention only slightly increased the water treatment time for the same wastewater, with an increase of no more than 5%. This indicates that the conductive ceramic membrane prepared using the method of this invention has good water treatment capabilities. Furthermore, when energized, the ceramic flat sheet membrane of this invention effectively removes small molecule organic pollutants that were previously difficult to remove from the purified water. After prolonged use, it was found that the surface contamination of the energized ceramic flat sheet membrane was significantly less than that of the untreated ceramic flat sheet membrane.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for inkjet printing metallic ink on a ceramic film surface, characterized in that, Includes the following steps: S1. Wet film preparation: Using an inkjet printing device, metallic ink is used to print inkjet print on both sides of the ceramic flat film to form a wet film layer. S2. Initial heat drying and shaping: Place the ceramic flat sheet membrane in a sealed chamber, with both ends of the ceramic flat sheet membrane connected to inert gas pipelines. Continuously introduce inert gas to maintain the internal pressure of the ceramic flat sheet membrane at 0.15-0.35 MPa. Slowly raise the temperature to 190℃ and continue drying for 3-5 hours. S3. High-temperature sintering and molding: After drying, increase the gas pressure inside the ceramic flat film to 0.5-0.7MPa and maintain it, then slowly raise the temperature to 350℃ and maintain it at 350℃ for high-temperature sintering and curing for 1.5-2.5h; S4. High-temperature rapid reduction: After sintering and curing, the temperature is rapidly increased to 420℃, and the temperature is maintained at 420℃ for 2-3 minutes for continuous reduction. Then the temperature is naturally cooled to 350℃, and the temperature is rapidly increased to 420℃ again for 2-3 minutes for continuous reduction. This process is repeated several times, and then the temperature is naturally cooled to room temperature to complete the metal inkjet printing of the ceramic flat film.

2. The method for inkjet printing metallic ink on a ceramic film surface according to claim 1, characterized in that, During inkjet printing in S1, the printhead of the inkjet printing device is tilted towards the plane of the ceramic flat film to spray ink.

3. The method for inkjet printing metallic ink on a ceramic film surface according to claim 1, characterized in that, The thickness of the wet film layer formed by inkjet printing on the surface of the ceramic flat film in S1 is 1-5 μm.

4. The method for inkjet printing metallic ink on a ceramic film surface according to claim 1, characterized in that, The inert gas in S2 is either nitrogen or argon.

5. The method for inkjet printing metallic ink on a ceramic film surface according to claim 1, characterized in that, In S2 and S3, the ceramic flat sheet membrane is placed vertically inside the sealed box.

6. The method for inkjet printing metallic ink on a ceramic film surface according to claim 1, characterized in that, The heating rate in S2 and S3 is controlled at 1-3℃ / min.

7. The method for inkjet printing metallic ink on a ceramic film surface according to claim 1, characterized in that, The heating rate in S4 is controlled at 5-8℃ / min.

8. The method for inkjet printing metallic ink on a ceramic film surface according to claim 1, characterized in that, In S4, the temperature is raised to 420℃ and the reduction is repeated 3-5 times.

9. A method for inkjet printing metallic ink on a ceramic film surface according to any one of claims 1 to 8, characterized in that, The metallic ink used in S1 contains organic copper salts, organic amines, inorganic ammonium salts, graphene oxide, and polyimide ultrafine powder.

10. The method for inkjet printing metallic ink on a ceramic film surface according to claim 9, characterized in that, Polyimide ultrafine powder is a thermosetting resin with an average particle size of 30-40 μm.

Images