A preparation method for a green tape of high-purity alumina ceramic

Abstract

The present invention belongs to the technical field of the preparation of green tapes for alumina ceramics, and specifically relates to a method for preparing high-purity alumina ceramic green tapes. An adjustment component is installed in the drying oven, a temperature supply component is installed on the drying oven, and a temperature supply component and a steam tank are installed on the support; the adjustment component includes a fixed plate and a driving plate. The fixed plate is fixedly installed in the drying oven, and a movable driving plate is installed inside the drying oven. The fixed plate and the driving plate divide the inside of the drying oven into a low-temperature chamber, a humidity replenishing chamber, and a high-temperature chamber. A fixed orifice plate is installed on the fixed plate, a movable orifice plate is installed on the driving plate, and a moisture sensor is installed in the drying oven. The present invention detects the fluidity of the slurry on the green tape, that is, detects the water content of the slurry, through the moisture sensor at the entrance of the drying oven, controls the cavity space of the low-temperature chamber and the steam input amount of the humidity replenishing chamber according to the fluidity of the slurry, and adjusts the solvent removal time for slurries with different fluidities.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of alumina ceramic green tapes, and particularly relates to a method for preparing high-purity alumina ceramic green tapes. Background Art

[0002] Alumina ceramic green tapes are flexible materials made of high-purity alumina powder and have extensive applications in fields such as electronic packaging and circuit boards. The quality of electronic ceramic products depends to a large extent on the quality of the green tapes. Therefore, the preparation of high-quality green tapes has become the key to the development in the field of functional ceramics.

[0003] The tape casting method is an important process for batch preparation of high-quality green tapes. In the tape casting method during batch preparation, first, ceramic powder, binder, plasticizer, and solvent are stirred evenly and ball milled to form a ceramic slurry with a certain viscosity coefficient; using a PET film tape as the casting substrate, the treated ceramic slurry is tape cast to form a green tape; the tape cast green tape is dried to remove the residual solvent and improve the strength of the green tape. The drying process of the ceramic green body is an important link in the tape casting production process and directly affects the production efficiency and quality of the product.

[0004] During the drying process of the ceramic green body, the solvent in the ceramic green body is likely to volatilize as the temperature rises, resulting in cracks or deformation of the green tape. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing high-purity alumina ceramic green tapes in view of the deficiencies of the prior art to solve the technical problems in the prior art.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A method for preparing high-purity alumina ceramic green tapes, which includes the following specific steps:

[0007] Step S1: Add ceramic powder to a ball mill, and add a dispersant, deionized water, binder, plasticizer, and solvent according to the powder ratio, mix evenly to obtain a mixture A;

[0008] Step S2: Add an antifoaming agent and a film-forming aid to the mixture A step by step, continue ball milling with a planetary ball mill to obtain a mixture B; then place the mixture B in a vacuum stirring tank for degassing to obtain a ceramic slurry;

[0009] Step S3: Heat and stir the ceramic slurry and keep it warm. Using a PET film tape as the casting substrate, tape cast the treated ceramic slurry to obtain a green tape;

[0010] Step S4: Place the green tape with delayed flow in the drying oven. The conveying device drives the green tape to pass through the low-temperature chamber, the humidity replenishing chamber, and the high-temperature chamber in sequence. During this process, the moisture sensor at the entrance of the drying oven detects the fluidity of the slurry on the green tape, and the multi-stage heating plates inside the drying oven assist in heating the green tape.

[0011] As a further optimization or improvement of this solution, step S4 specifically includes the following steps:

[0012] Step S401: When the fluidity of the slurry on the green tape is low, the moisture sensor controls the cylinder to extend. The cylinder drives the active plate to move from the humidity replenishing chamber towards the low-temperature chamber through the push-pull rod. The slider on the active plate drives the connecting rod and the driven plate to move. When the cylinder drives the active plate to cross one of the low-temperature branch tubes, it stops. At this time, the space of the low-temperature chamber decreases, and the space of the humidity replenishing chamber increases;

[0013] Step S402: During the process of the cylinder 7 driving the active plate 802 and the driven plate 803 to move, the moving orifice plate 806 on the active plate 802 moves relative to the fixed orifice plate 807, and the through holes on the moving orifice plate 806 gradually coincide with the through holes on the fixed orifice plate 807;

[0014] Step S403: When the green tape passes through the low-temperature chamber, due to the decrease in the space of the low-temperature chamber, the passing time of the green tape through the low-temperature chamber decreases. At the same time, the low-temperature branch tube blows dry hot air into the low-temperature chamber, providing a low-humidity volatilization environment while removing the internal solvent of the green tape;

[0015] Step S404: When the green tape passes through the humidity replenishing chamber, the steam tank injects steam into the humidity replenishing chamber. Since both the high-temperature branch tube and the low-temperature branch tube are located inside the humidity replenishing chamber, the hot air from the high-temperature branch tube and the low-temperature branch tube is mixed and heated in the humidity replenishing chamber, so that the temperature of the steam and the hot air inside the humidity replenishing chamber is balanced between the temperatures of the low-temperature chamber and the high-temperature chamber. At this time, the steam and the hot air inside the humidity replenishing chamber are blown towards the green tape through the through holes on the fixed orifice plate and the moving orifice plate;

[0016] Step S405: When the green tape passes through the high-temperature chamber, the high-temperature air pressure tank heats the green tape inside the high-temperature chamber to a high temperature through the high-temperature branch tube to dry it.

[0017] As a further optimization or improvement of this solution, step S4 specifically includes the following steps:

[0018] Step S411: When the fluidity of the slurry on the green tape is high, the moisture sensor controls the cylinder to retract. As the cylinder drives the active plate to move towards the humidity replenishing chamber, the push-pull rod drives the slider to slide along the chute, separating the active plate from the driven plate. When the active plate returns to its previous position, the cylinder closes. During this process, the space of the low-temperature chamber increases, and the space of the humidity replenishing chamber decreases;

[0019] Step S412: When the cylinder drives the active plate to move, the moving orifice plate on the active plate moves relative to the fixed orifice plate, causing the through holes on the moving orifice plate and the through holes on the fixed orifice plate to gradually stagger, and reducing the steam output of the humidification chamber;

[0020] Step S413: When the green ceramic tape passes through the low-temperature chamber, the space of the low-temperature chamber increases, and the time for the green ceramic tape to pass through the low-temperature chamber increases. At the same time, the moisture absorption block can suck out the moisture inside the low-temperature chamber;

[0021] Step S414: When the green ceramic tape passes through the humidification chamber, due to the strong fluidity of the slurry, the slurry can automatically flow to smooth out the fine cracks caused by the volatilization inside the green ceramic tape. The humidification chamber does not need to increase the fluidity of the slurry through steam. The multi-stage heating plates are started, and the multi-stage heating plates with stepped temperature increase gradually heat the green ceramic tape.

[0022] As a further optimization or improvement of this solution, an adjustment component is installed inside the drying box, a temperature supply component is installed on the drying box, and a temperature supply component and a steam tank are installed on the bracket;

[0023] The adjustment component includes a fixed plate and an active plate. The fixed plate is fixedly installed inside the drying box, and a movable active plate is installed inside the drying box. The fixed plate and the active plate divide the inside of the drying box into a low-temperature chamber, a humidification chamber, and a high-temperature chamber. A fixed orifice plate is installed on the fixed plate, a moving orifice plate is installed on the active plate, and the moving orifice plate and the fixed orifice plate are in sliding fit;

[0024] The temperature supply component includes a high-temperature air pressure tank and a low-temperature air pressure tank. The high-temperature air pressure tank is connected to the high-temperature chamber, the low-temperature air pressure tank is connected to the low-temperature chamber, the steam tank is connected to the humidification chamber, and a moisture sensor is installed inside the drying box.

[0025] As a further optimization or improvement of this solution, a cylinder is installed inside the humidification chamber. The cylinder is connected to the active plate through a push-pull rod. A plurality of multi-stage heating plates are installed at the bottom of the drying box, and exhaust fans are installed on both the low-temperature chamber and the high-temperature chamber.

[0026] As a further optimization or improvement of this solution, a connecting rod is installed on the driven plate. A sliding groove is opened inside the connecting rod. A sliding block is installed on the push-pull rod. The sliding block slides inside the sliding groove. An electromagnetic chuck is installed inside the sliding groove, and the electromagnetic chuck adsorbs the sliding block.

[0027] As a further optimization or improvement of this solution, a sealing frame is installed on the driven plate, a moisture absorption block is installed on the active plate, and the sealing frame covers the moisture absorption block.

[0028] As a further optimization or improvement of this solution, sealing strips are installed on the fixed plate and the active plate, and the fixed plate and the active plate contact the top of the drying box through the sealing strips thereon.

[0029] As a further optimization or improvement of this solution, the low-temperature gas pressure tank is connected to the low-temperature cavity through a low-temperature branch pipe, and the high-temperature gas pressure tank is connected to the high-temperature cavity through a high-temperature branch pipe. One of the heads on the high-temperature branch pipe is located in the humidification cavity.

[0030] As a further optimization or improvement of this solution, the solvent is a mixture of anhydrous ethanol, methyl ethyl ketone, and n-butanol.

[0031] Advantages of the present invention:

[0032] (1) In the present invention, the fluidity of the slurry on the green tape is detected by a moisture sensor; when the fluidity of the slurry on the green tape is low, the volume of the low-temperature cavity is adjusted to be smaller by a cylinder, the steam output of the humidification cavity increases, and the time for the green tape to pass through the low-temperature cavity is reduced, avoiding the phenomenon that the slurry with low fluidity on the green tape stays in the low-temperature cavity for a long time, resulting in excessive drying and cracking of the slurry. At the same time, since the dry hot air blown into the low-temperature cavity by the low-temperature branch pipe provides a low-humidity volatilization environment and removes the solvent inside the green tape;

[0033] Furthermore, when the green tape passes through the humidification cavity, the steam tank injects steam into the humidification cavity. Since both the high-temperature branch pipe and the low-temperature branch pipe are located inside the humidification cavity, the hot air from the high-temperature branch pipe and the low-temperature branch pipe is mixed in the humidification cavity and heats the steam, so that the temperature of the steam and hot air inside the humidification cavity is balanced between the temperatures of the low-temperature cavity and the high-temperature cavity. At this time, the steam and hot air inside the humidification cavity are blown onto the green tape through the through holes on the fixed orifice plate and the moving orifice plate, gradually heating the green tape, reducing the influence of the temperature difference between the low-temperature cavity and the high-temperature cavity on the green tape. At the same time, the high-humidity steam can improve the fluidity of the slurry on the green tape and accelerate the flow of the slurry to smooth out the fine cracks caused by the volatilization of the solvent from the inside of the green tape.

[0034] (2) When the fluidity of the slurry on the green tape is strong, that is, the amount of solvent inside the slurry is large, the cylinder controls the volume of the low-temperature cavity to increase, controls the steam output of the humidification cavity to decrease, and controls the moisture-absorbing block to be exposed in the low-temperature cavity, increasing the time for the green tape to pass through the low-temperature cavity, thereby completely removing the solvent inside the green tape. The moisture-absorbing block can absorb the moisture inside the low-temperature cavity, providing a drier environment for the low-temperature cavity. Combined with the dry hot air from the low-temperature branch pipe, it removes the moisture of the slurry and improves the volatility of ethanol in the solvent;

[0035] Furthermore, when the green tape passes through the humidification cavity, since the through holes on the moving orifice plate and the fixed orifice plate are staggered, the steam output of the humidification cavity is reduced or stopped. At the same time, due to the strong fluidity of the slurry, the slurry can automatically flow to smooth out the fine cracks caused by the volatilization inside the green tape, and there is no need for the humidification cavity to increase the fluidity of the slurry through steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0038] Figure 2 This is a schematic diagram of the internal structure of the present invention.

[0039] Figure 3 This is a front view of the internal structure of the present invention.

[0040] Figure 4 is Figure 3 an enlarged view of the structure of part A of

[0041] Figure 5 This is an exploded view of the overall structure of the adjustment assembly.

[0042] Figure 6 This is a schematic diagram of the connection between the air cylinder and the adjustment assembly.

[0043] Figure 7 is Figure 6 a schematic diagram of the structure of part B of

[0044] In the figure, the markings are: 1, drying oven; 101, low-temperature chamber; 102, humidification replenishment chamber; 103, high-temperature chamber; 2, bracket; 3, temperature supply assembly; 301, high-temperature air pressure tank; 302, high-temperature branch pipe; 304, low-temperature air pressure tank; 305, low-temperature branch pipe; 4, steam tank; 5, exhaust fan; 6, multi-stage heating plate; 7, air cylinder; 8, adjustment assembly; 801, fixing plate; 802, active plate; 803, driven plate; 804, sealing frame; 805, moisture absorption block; 806, movable orifice plate; 807, fixed orifice plate; 808, connecting rod; 809, sliding groove; 810, push-pull rod; 811, slider; 812, electromagnetic chuck; 813, sealing strip; 9, moisture sensor. Specific embodiments

[0045] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0046] See Figures 1 - 7 , a method for preparing a high-purity alumina ceramic green tape, which includes the following specific steps:

[0047] Step S1: Add ceramic powder to a ball mill, and add a dispersant, deionized water, a binder, a plasticizer, and a solvent according to the powder ratio, mix evenly to obtain a mixed material A;

[0048] Step S2: Add the defoamer and film-forming aid to the mixed material A step by step, and continue ball milling with a planetary ball mill to obtain the mixed material B; then place the mixed material B in a vacuum stirring tank for defoaming to obtain the ceramic slurry;

[0049] Step S3: Heat and stir the ceramic slurry and keep it warm. Using the PET film tape as the casting substrate, cast and form the treated ceramic slurry to obtain the green tape;

[0050] Step S4: Place the cast green tape in the drying oven 1. The conveying device drives the green tape to pass through the low-temperature chamber 101, the humidification chamber 102 and the high-temperature chamber 103 in sequence. During this process, the moisture sensor 9 at the entrance of the drying oven 1 detects the fluidity of the slurry on the green tape, and the multi-stage heating plates 6 inside the drying oven 1 assist in heating the green tape.

[0051] It should be noted that the conveying device is a conventional conveyor belt in the prior art, and the present invention will not elaborate on it, and it does not affect the integrity of the solution.

[0052] The ceramic powder of the present invention includes 996 alumina, 96 alumina, 90 black porcelain and 92 black porcelain;

[0053] Based on different powders, mix them evenly with a dispersant, deionized water, a binder, and a plasticizer, and ball mill for about 5 hours to obtain the mixed material A; then add the defoamer and film-forming aid to the mixed material A step by step, and continue ball milling with a planetary ball mill for about 5 hours to obtain the mixed material B; then defoam the mixed material B in a vacuum stirring tank for 5 - 10 hours to obtain a ceramic slurry with a viscosity in the range of 5000 - 15000 mPa·S; heat and stir the ceramic slurry and keep it warm, the heat preservation temperature is 30°C, and it is characterized in that sedimentation is prevented in the casting preparation area, and the stirring speed is 15 rpm. Then, using the PET film tape as the casting substrate, cast and form the treated ceramic slurry to obtain the green tape; set the state of the green tape during casting to apply a tensile force of 90 N to the green tape through the roller at a temperature of 30°C, the gap between the equipment scraper and the conveyor belt is 0.2 - 2 mm (adjusted according to the thickness of the prepared green tape), and the conveyor belt speed is 0.1 - 0.6 m / min. The air inlet speed of the low-temperature chamber 101 is set to 500 - 550 rpm, the exhaust is 1550 - 1650 rpm, the air inlet speed of the high-temperature chamber 103 is 450 - 500 rpm, and the exhaust speed is 1500 - 1550 rpm.

[0054] When the present invention produces 96 alumina, the thicknesses of the cast green tapes are three specifications: above 500 mm, 300 - 500 mm, and within 300 mm. When the casting thickness is less than 300 mm, at this time, the viscosity of the slurry is regulated to 5000 - 6000 Pa·s through vacuum defoaming.

[0055] The temperatures of the multi-stage heating plate 6 are set to 35, 45, 55, 60, and 70 °C. The air intake of the low-temperature chamber 101 is 450 rpm, and the air exhaust of the low-temperature chamber 101 is 1450 rpm. The air intake of the high-temperature chamber 103 is 500 rpm, and the air exhaust of the high-temperature chamber 103 is 1550 rpm. When the casting thickness is between 300 - 500 mm, the viscosity of the slurry is regulated to be 10000 - 11000 Pa·s through vacuum degassing. The temperatures of the multi-stage heating plate 6 are set to 42, 53, 63, 70, and 80. The air intake of the low-temperature chamber 101 is 450 rpm, and the air exhaust of the low-temperature chamber 101 is 1450 rpm. The air intake of the high-temperature chamber 103 is 500 rpm, and the air exhaust of the high-temperature chamber 103 is 1550 rpm. When the casting thickness is greater than 500 mm, the viscosity coefficient is 12000 - 15000 Pa·s after vacuum degassing treatment, and the other parameters are the same as those for 300 - 500 mm.

[0056] When the present invention produces 996 alumina, the thicknesses of the green ceramic tapes obtained by casting are three specifications: above 500 mm, between 300 - 500 mm, and below 300 mm. When the casting thickness is less than 300 mm, the viscosity of the slurry is regulated to be 5000 - 7000 Pa·s through vacuum degassing.

[0057] The temperatures of the multi-stage heating plate 6 are set to 40, 50, 55, 60, and 60 °C. The air intake of the low-temperature chamber 101 is 450 rpm, and the air exhaust of the low-temperature chamber 101 is 1450 rpm. The air intake of the high-temperature chamber 103 is 500 rpm, and the air exhaust of the high-temperature chamber 103 is 1550 rpm. When the casting thickness is between 300 - 500 mm, the viscosity of the slurry is regulated to be 9000 - 11000 Pa·s through vacuum degassing. The temperatures of the multi-stage heating plate 6 are set to 40, 50, 60, 70, and 80 °C. The air intake of the low-temperature chamber 101 is 550 rpm, and the air exhaust of the low-temperature chamber 101 is 1650 rpm. The air intake of the high-temperature chamber 103 is 500 rpm, and the air exhaust of the high-temperature chamber 103 is 1550 rpm. When vacuum degassing treatment is carried out, the viscosity coefficient is 12000 - 14000, and the other parameters are the same as those for 300 - 500 mm.

[0058] When the present invention produces alumina 90 black porcelain / 92 black porcelain, the thicknesses of the green tape obtained by casting are four specifications: above 330 mm, 330 mm, 133 - 264 mm, and within 133 mm. When the casting thickness is less than 133 mm, the viscosity of the slurry is regulated to 5000 - 5500 Pa·s through vacuum degassing. The temperatures of the multi-stage heating plate 6 are set to 40, 50, 55, 60, 60 °C. The air intake of the low-temperature chamber 101 is 450 rpm, and the air exhaust of the low-temperature chamber 101 is 1450 rpm. The air intake of the high-temperature chamber 103 is 500 rpm, and the air exhaust of the high-temperature chamber 103 is 1550 rpm. When the casting thickness is between 133 - 264 mm, the viscosity of the slurry is regulated to 8000 - 9000 Pa·s through vacuum degassing, and the other parameters are the same as those below 133 mm. When the casting thickness is 330 mm, the viscosity of the slurry is regulated to 10000 - 11000 Pa·s through vacuum degassing. The temperatures of the multi-stage heating plate 6 are set to 40, 50, 60, 70, 80 °C. The air intake of the low-temperature chamber 101 is 600 rpm, and the air exhaust of the low-temperature chamber 101 is 1650 rpm. The air intake of the high-temperature chamber 103 is 550 rpm, and the air exhaust of the high-temperature chamber 103 is 1550 rpm. When the casting thickness is greater than 330 mm, the viscosity coefficient after vacuum degassing treatment is 12000 - 15000 Pa·s, and the other parameters are the same as those of 330 mm.

[0059] During the preparation of the green tape, the particle size of the ceramic powder selected is 3 - 4 μm. The ceramic particle size of 3 - 4 μm can make the powder distribution more uniform while ensuring the packing density of the green tape, enabling the powder to form a more compact packing structure, thereby improving the densification of the green tape. After sintering, the pores and porosity of the ceramic core are smaller, and the grain boundary density increases, thereby ensuring the microstructure and properties of the ceramic core, such as flexural strength and creep resistance.

[0060] The solvent preferably includes one or more of toluene, xylene, methyl ethyl ketone, ethanol, and ethyl acetate, enabling the solvent to fully disperse each component, improving the fluidity of the alumina ceramic casting slurry, and having good volatility.

[0061] See Figures 3 - 7 , the step S4 specifically includes the following steps:

[0062] Step S401: When the fluidity of the slurry on the green tape is low, the moisture sensor 9 controls the cylinder 7 to extend. The cylinder 7 drives the active plate 802 to move from the humidification chamber 102 towards the low-temperature chamber 101 through the push-pull rod 810. The slider 811 on the active plate 802 drives the connecting rod 808 and the driven plate 803 to move. When the cylinder 7 drives the active plate 802 to cross one of the low-temperature branch tubes 305 and then stops, at this time, the cavity space of the low-temperature chamber 101 decreases, and the cavity space of the humidification chamber 102 increases;

[0063] Step S402: When the cylinder 7 drives the active plate 802 and the driven plate 803 to move, the movable orifice plate 806 on the active plate 802 moves relative to the fixed orifice plate 807, and the through holes on the movable orifice plate 806 gradually overlap with the through holes on the fixed orifice plate 807;

[0064] Step S403: When the green porcelain tape passes through the low temperature chamber 101, the time for the green porcelain tape to pass through the low temperature chamber 101 is reduced due to the reduction of the cavity space of the low temperature chamber 101. At the same time, the low temperature branch pipe 305 blows dry hot air into the low temperature chamber 101, providing a low humidity volatilization environment while removing the solvent inside the green porcelain tape;

[0065] Step S404: When the green porcelain belt passes through the moistening chamber 102, the steam tank 4 injects steam into the moistening chamber 102. Since the high-temperature branch pipe 302 and the low-temperature branch pipe 305 are both located inside the moistening chamber 102, the hot air from the high-temperature branch pipe 302 and the low-temperature branch pipe 305 is introduced into the moistening chamber 102 to mix and heat the steam, so that the temperature of the steam and hot air inside the moistening chamber 102 is balanced between the temperature of the low-temperature chamber 101 and the temperature of the high-temperature chamber 103. At this time, the steam and hot air inside the moistening chamber 102 are blown toward the green porcelain belt through the through holes on the fixed orifice plate 807 and the movable orifice plate 806;

[0066] Step S405: When the green porcelain tape passes through the high temperature chamber 103, the high temperature pressure tank 301 heats the green porcelain tape inside the high temperature chamber 103 through the high temperature branch pipe 302 to dry it.

[0067] See also Figures 3 - 7 , the step S4 specifically comprises the following steps:

[0068] Step S411: When the fluidity of the slurry on the green porcelain belt is strong, the moisture sensor 9 controls the cylinder 7 to retract. As the cylinder 7 drives the active plate 802 to move toward the moistening chamber 102, the push-pull rod 810 drives the slider 811 to slide along the slide groove 809, so that the active plate 802 is separated from the driven plate 803. When the active plate 802 returns to its previous position, the cylinder 7 is closed. In this process, the space of the low-temperature chamber 101 increases, and the space of the moistening chamber 102 decreases.

[0069] Step S412: When the cylinder 7 drives the active plate 802 to move, the movable orifice plate 806 on the active plate 802 moves relative to the fixed orifice plate 807, so that the through holes on the movable orifice plate 806 and the through holes on the fixed orifice plate 807 are gradually staggered, and the steam output of the moisturizing chamber 102 is reduced;

[0070] Step S413: When the green porcelain tape passes through the low temperature chamber 101, the cavity space of the low temperature chamber 101 increases, the time for the green porcelain tape to pass through the low temperature chamber 101 increases, and at the same time, the moisture absorption block 805 can absorb the moisture inside the low temperature chamber 101;

[0071] Step S414: When the green tape passes through the humidification chamber 102, due to the strong fluidity of the slurry, the slurry can automatically flow to smooth out the fine cracks caused by the volatilization inside the green tape. The humidification chamber 102 does not need to increase the fluidity of the slurry through steam. The multi-stage heating plate 6 is activated, and the multi-stage heating plate 6 with stepped temperature increase gradually heats the green tape.

[0072] See Figures 3 - 7 , an adjustment component 8 is installed inside the drying oven 1, a temperature supply component 3 is installed on the drying oven 1, and the temperature supply component 3 and the steam tank 4 are installed on the support 2;

[0073] The adjustment component 8 includes a fixed plate 801 and a driving plate 802. The fixed plate 801 is fixedly installed inside the drying oven 1, and a movable driving plate 802 is installed inside the drying oven 1. The fixed plate 801 and the driving plate 802 divide the inside of the drying oven 1 into a low-temperature chamber 101, a humidification chamber 102, and a high-temperature chamber 103. A fixed orifice plate 807 is installed on the fixed plate 801, a movable orifice plate 806 is installed on the driving plate 802, and the movable orifice plate 806 and the fixed orifice plate 807 are in sliding fit;

[0074] The temperature supply component 3 includes a high-temperature air pressure tank 301 and a low-temperature air pressure tank 304. The high-temperature air pressure tank 301 is connected to the high-temperature chamber 103, the low-temperature air pressure tank 304 is connected to the low-temperature chamber 101, the steam tank 4 is connected to the humidification chamber 102, and a moisture sensor 9 is installed inside the drying oven 1.

[0075] Specifically, a cylinder 7 is installed inside the humidification chamber 102, and the cylinder 7 is connected to the driving plate 802 through a push-pull rod 810.

[0076] Specifically, the low-temperature air pressure tank 304 is connected to the low-temperature chamber 101 through a low-temperature branch pipe 305, the high-temperature air pressure tank 301 is connected to the high-temperature chamber 103 through a high-temperature branch pipe 302, and one of the heads on the high-temperature branch pipe 302 is located inside the humidification chamber 102.

[0077] It should be noted that in the present invention, the moisture sensor 9 at the entrance of the drying oven 1 detects the fluidity of the slurry on the green tape, that is, detects the water content of the slurry, controls the cavity space of the low-temperature chamber 101 and the steam input amount of the humidification chamber 102 according to the fluidity of the slurry, and adjusts the solvent removal time for slurries with different fluidities. Control valves are installed at the output ends of the high-temperature air pressure tank 301 and the low-temperature air pressure tank 304 to control the air intake volume.

[0078] See Figure 7 , a connecting rod 808 is installed on the driven plate 803, a chute 809 is opened inside the connecting rod 808, a slider 811 is installed on the push-pull rod 810, the slider 811 slides inside the chute 809, and an electromagnetic chuck 812 is installed inside the chute 809. The electromagnetic chuck 812 adsorbs the slider 811.

[0079] It should be noted that when it is necessary to drive the driving plate 802 and the driven plate 803 to move synchronously through the cylinder 7, the electromagnetic chuck 812 is activated, that is, the push-pull rod 810 is connected to the connecting rod 808 through the slider 811. At this time, the driving plate 802 and the driven plate 803 can be driven to move synchronously through the cylinder 7; if it is necessary to drive the driving plate 802 to move alone, the electromagnetic chuck 812 can be turned off, and the driving plate 802 can be driven to move alone through the cylinder 7.

[0080] See Figure 7 A sealing frame 804 is installed on the driven plate 803, and a moisture-absorbing block 805 is installed on the driving plate 802. The sealing frame 804 covers the moisture-absorbing block 805.

[0081] It should be noted that a low-humidity environment is conducive to solvent volatilization. In a humid environment, the moisture in the air will slow down the evaporation rate of ethanol inside the solvent.

[0082] The moisture-absorbing block 805 is made of a strong water-absorbing material. When the fluidity of the slurry on the green ceramic tape is relatively strong, the sealing frame 804 is separated from the sealed cover of the moisture-absorbing block 805. At this time, the moisture-absorbing block 805 is exposed in the low-temperature chamber 101, so that the moisture-absorbing block 805 adsorbs the moisture in the air inside the low-temperature chamber 101, provides a low-humidity space for the low-temperature chamber 101, and accelerates the evaporation of ethanol inside the solvent.

[0083] See Figures 4 - 6 Sealing strips 813 are installed on the fixed plate 801 and the driving plate 802. The fixed plate 801 and the driving plate 802 contact the top of the drying oven 1 through the sealing strips 813 thereon.

[0084] It should be noted that the fixed plate 801 and the driving plate 802 seal and separate the low-temperature chamber 101, the humidification chamber 102, and the high-temperature chamber 103 through the sealing strips 813.

[0085] See Figures 2 - 3 A plurality of multi-stage heating plates 6 are installed at the bottom of the drying oven 1, and exhaust fans 5 are installed on both the low-temperature chamber 101 and the high-temperature chamber 103.

[0086] It should be noted that the temperature of the multi-stage heating plates 6 increases in a stepped manner. Five groups of multi-stage heating plates 6 are provided, two groups are provided inside both the low-temperature chamber 101 and the high-temperature chamber 103, and one group is provided inside the humidification chamber 102 to reduce the influence of the temperature difference between the low-temperature chamber 101 and the high-temperature chamber 103 on the drying of the green ceramic tape.

[0087] The implementation principle of the present invention is as follows:

[0088] During use, the green tape with delayed flow is placed in the drying oven 1, and the conveying device drives the green tape to pass through the low-temperature chamber 101, the humidity replenishing chamber 102, and the high-temperature chamber 103 in sequence. During this process, the moisture sensor 9 at the entrance of the drying oven 1 detects the fluidity of the slurry on the green tape, that is, detects the water content of the slurry.

[0089] When the fluidity of the slurry on the green tape is low, that is, the solvent amount inside the slurry is small, the moisture sensor 9 controls the cylinder 7 to extend. Refer to Figure 7 , the cylinder 7 drives the active plate 802 to move from the humidity replenishing chamber 102 towards the low-temperature chamber 101 through the push-pull rod 810. At the same time, the slider 811 on the active plate 802 drives the connecting rod 808 and the driven plate 803 to move. At this time, the active plate 802 and the driven plate 803 move synchronously towards the low-temperature chamber 101. Refer to Figure 4 , when the cylinder 7 drives the active plate 802 to stop after passing over one of the low-temperature branch tubes 305, at this time, the cavity space of the low-temperature chamber 101 decreases, and the cavity space of the humidity replenishing chamber 102 increases; during the process of the cylinder 7 driving the active plate 802 and the driven plate 803 to move, the moving orifice plate 806 on the active plate 802 moves relative to the fixed orifice plate 807, and the through holes on the moving orifice plate 806 gradually coincide with the through holes on the fixed orifice plate 807, and the steam output of the humidity replenishing chamber 102 increases.

[0090] When the green tape passes through the low-temperature chamber 101, due to the reduced cavity space of the low-temperature chamber 101, the passing time of the green tape through the low-temperature chamber 101 is reduced. While removing the solvent inside the green tape, it avoids the phenomenon that the slurry with relatively low fluidity on the green tape stays in the low-temperature chamber 101 for a long time, resulting in excessive drying and cracking of the slurry. At the same time, since the dry hot air blown by the low-temperature header pipe 305 into the low-temperature chamber 101 provides a low-humidity volatilization environment and removes the solvent inside the green tape; when the green tape passes through the humidification chamber 102, the steam tank 4 injects steam into the humidification chamber 102. Since both the high-temperature header pipe 302 and the low-temperature header pipe 305 are located inside the humidification chamber 102, the hot air from the high-temperature header pipe 302 and the low-temperature header pipe 305 is introduced into the humidification chamber 102 and mixed to heat the steam, so that the temperature of the steam and hot air inside the humidification chamber 102 is balanced between the temperatures of the low-temperature chamber 101 and the high-temperature chamber 103. At this time, the steam and hot air inside the humidification chamber 102 are blown onto the green tape through the through holes on the fixed orifice plate 807 and the moving orifice plate 806, gradually heating the green tape, reducing the influence of the temperature difference between the low-temperature chamber 101 and the high-temperature chamber 103 on the green tape. At the same time, the high-humidity steam can improve the fluidity of the slurry on the green tape, accelerating the flow of the slurry to smooth out the fine cracks caused by the volatilization of the solvent from the inside of the green tape; when the green tape passes through the high-temperature chamber 103, the high-temperature air pressure tank 301 heats the green tape inside the high-temperature chamber 103 to a high temperature through the high-temperature header pipe 302 to dry it. (Since the dry hot air blown by the low-temperature header pipe 305 into the low-temperature chamber 101 provides a low-humidity volatilization environment and removes the solvent inside the green tape, the volatilization of the solvent diffusing out from the inside of the green tape is likely to generate fine cracks on the green tape).

[0091] When the fluidity of the slurry on the green tape is strong, that is, the amount of solvent inside the slurry is large, the moisture sensor 9 controls the cylinder 7 to retract. See Figure 7 , the electromagnetic chuck 812 is closed. As the cylinder 7 drives the active plate 802 to move towards the humidification chamber 102, the push-pull rod 810 drives the slider 811 to slide along the chute 809, separating the active plate 802 from the driven plate 803. At this time, the sealing frame 804 on the driven plate 803 disengages from the seal of the moisture absorption block 805. When the active plate 802 returns to its previous position, the cylinder 7 is closed. See Figure 4 , during this process, the space of the low-temperature chamber 101 increases, the space of the humidification chamber 102 decreases. At the same time, when the cylinder 7 drives the active plate 802 to move, the moving orifice plate 806 on the active plate 802 moves relative to the fixed orifice plate 807, causing the through holes on the moving orifice plate 806 and the through holes on the fixed orifice plate 807 to gradually stagger, reducing the steam output of the humidification chamber 102.

[0092] When the green tape passes through the low-temperature chamber 101, the cavity space of the low-temperature chamber 101 increases, and the passing time of the green tape through the low-temperature chamber 101 increases. Since there is a relatively large amount of solvent inside the slurry, the passing time of the green tape through the low-temperature chamber 101 increases, thereby thoroughly removing the solvent inside the green tape. At the same time, the moisture absorption block 805 can suck out the moisture inside the low-temperature chamber 101, providing a more dry environment for the low-temperature chamber 101. In cooperation with the drying hot air of the low-temperature branch pipe 305, while removing the moisture of the slurry, the volatility of ethanol in the solvent is increased; when the green tape passes through the humidification chamber 102, since the through holes on the movable orifice plate 806 and the through holes on the fixed orifice plate 807 are staggered, the steam output of the humidification chamber 102 decreases or stops. At the same time, due to the strong fluidity of the slurry, the slurry can automatically flow to flatten the fine cracks caused by the volatilization inside the green tape, and the humidification chamber 102 does not need to increase the fluidity of the slurry through steam; the multi-stage heating plate 6 is started, and the multi-stage heating plate 6 with stepped temperature increase can gradually heat the green tape to reduce the influence of the temperature difference between the low-temperature chamber 101 and the high-temperature chamber 103 on the green tape; when the green tape passes through the high-temperature chamber 103, the high-temperature air pressure tank 301 heats the green tape inside the high-temperature chamber 103 through the high-temperature branch pipe 302 to make it dry.

[0093] While drying the green tape, the exhaust fan 5 is started, and the exhaust fan 5 accelerates the flow of hot air inside the low-temperature chamber 101 and the high-temperature chamber 103, so that the exhaust fan 5 quickly discharges the solvent vapor volatilized during the drying process of the green tape in the low-temperature chamber 101, preventing the vapor from condensing on the green tape and causing defects.

[0094] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A method for preparing a high-purity alumina ceramic green tape, characterized in that: The specific steps include: Step S1: adding ceramic powder into a ball mill, adding a dispersant, deionized water, a binder, a plasticizer and a solvent according to the proportion of the powder, mixing evenly and obtaining a mixture A; Step S2: adding a defoaming agent and a film-forming aid to the mixture A step by step, and continuing to ball mill with a planetary ball mill to obtain a mixture B; then placing the mixture B in a vacuum stirring tank for degassing to obtain a ceramic slurry; Step S3: heating, stirring and keeping the ceramic slurry warm, using the PET film tape as a tape-casting substrate, and tape-casting the treated ceramic slurry to obtain a green ceramic tape; Step S4: placing the green porcelain tape after tape casting in a drying box (1), and driving the green porcelain tape through a low-temperature chamber (101), a moistening chamber (102), and a high-temperature chamber (103) in sequence by a conveying device. During this process, a moisture sensor (9) at the entrance of the drying box (1) detects the fluidity of the slurry on the green porcelain tape, and a multi-stage heating plate (6) inside the drying box (1) assists in heating the green porcelain tape. The step S4 specifically comprises the following steps: Step S401: When the fluidity of the slurry on the green porcelain belt is low, the moisture sensor (9) controls the cylinder (7) to extend, and the cylinder (7) drives the active plate (802) to move from the moistening chamber (102) to the low-temperature chamber (101) through the push-pull rod (810), and the slider (811) on the active plate (802) drives the connecting rod (808) and the driven plate (803) to move. When the cylinder (7) drives the active plate (802) to pass over one of the low-temperature branch pipes (305), it stops. At this time, the cavity space of the low-temperature chamber (101) is reduced, and the cavity space of the moistening chamber (102) is increased; Step S402: When the cylinder (7) drives the active plate (802) and the driven plate (803) to move, the movable orifice plate (806) on the active plate (802) moves relative to the fixed orifice plate (807), and the through holes on the movable orifice plate (806) gradually overlap with the through holes on the fixed orifice plate (807); Step S403: when the green porcelain tape passes through the low-temperature chamber (101), the time for the green porcelain tape to pass through the low-temperature chamber (101) is reduced due to the reduction in the cavity space of the low-temperature chamber (101). At the same time, the low-temperature branch pipe (305) blows dry hot air into the low-temperature chamber (101), thereby providing a low-humidity volatilization environment and removing the solvent inside the green porcelain tape; Step S404: when the green porcelain belt passes through the moistening chamber (102), the steam tank (4) injects steam into the moistening chamber (102). Since the high-temperature branch pipe (302) and the low-temperature branch pipe (305) are both located inside the moistening chamber (102), the hot air from the high-temperature branch pipe (302) and the low-temperature branch pipe (305) are introduced into the moistening chamber (102) to mix and heat the steam, so that the temperature of the steam and hot air inside the moistening chamber (102) is balanced between the temperature of the low-temperature chamber (101) and the temperature of the high-temperature chamber (103). At this time, the steam and hot air inside the moistening chamber (102) are blown toward the green porcelain belt through the through holes on the fixed orifice plate (807) and the movable orifice plate (806); Step S405: When the green porcelain tape passes through the high-temperature chamber (103), the high-temperature pressure tank (301) heats the green porcelain tape inside the high-temperature chamber (103) through the high-temperature branch pipe (302) to dry it.

2. The method for preparing a high-purity alumina ceramic green tape according to claim 1, characterized in that: The step S4 specifically comprises the following steps: Step S411: When the fluidity of the slurry on the green porcelain belt is relatively strong, the moisture sensor (9) controls the cylinder (7) to retract. As the cylinder (7) drives the active plate (802) to move toward the moistening chamber (102), the push-pull rod (810) drives the slider (811) to slide along the slide groove (809), so that the active plate (802) and the driven plate (803) are separated. When the active plate (802) returns to its previous position, the cylinder (7) is closed. During this process, the space of the low-temperature chamber (101) increases, and the space of the moistening chamber (102) decreases. Step S412: when the cylinder (7) drives the active plate (802) to move, the movable orifice plate (806) on the active plate (802) moves relative to the fixed orifice plate (807), so that the through holes on the movable orifice plate (806) and the through holes on the fixed orifice plate (807) gradually stagger, and the steam output of the moisturizing chamber (102) decreases; Step S413: when the green porcelain tape passes through the low-temperature chamber (101), the cavity space of the low-temperature chamber (101) increases, the time for the green porcelain tape to pass through the low-temperature chamber (101) increases, and at the same time, the moisture absorption block (805) can absorb moisture inside the low-temperature chamber (101); Step S414: When the raw porcelain tape passes through the moistening chamber (102), the slurry has high fluidity and can automatically flow to smooth out the fine cracks caused by volatilization inside the raw porcelain tape. The moistening chamber (102) does not need to use steam to increase the fluidity of the slurry. The multi-stage heating plate (6) is started, and the multi-stage heating plate (6) with stepped heating gradually heats the raw porcelain tape.

3. The method for preparing a high-purity alumina ceramic green tape according to claim 1, characterized in that: An adjusting component (8) is installed in the drying box (1), a heating component (3) is installed on the drying box (1), and a heating component (3) and a steam tank (4) are installed on the bracket (2); The regulating assembly (8) comprises a fixed plate (801) and an active plate (802); the fixed plate (801) is fixedly mounted in the drying box (1); a movable active plate (802) is mounted inside the drying box (1); the fixed plate (801) and the active plate (802) divide the interior of the drying box (1) into a low-temperature chamber (101), a moistening chamber (102), and a high-temperature chamber (103); a fixed orifice plate (807) is mounted on the fixed plate (801); a movable orifice plate (806) is mounted on the active plate (802); and the movable orifice plate (806) and the fixed orifice plate (807) are slidably matched; The heating component (3) comprises a high-temperature pressure tank (301) and a low-temperature pressure tank (304); the high-temperature pressure tank (301) is connected to the high-temperature chamber (103); the low-temperature pressure tank (304) is connected to the low-temperature chamber (101); the steam tank (4) is connected to the moisturizing chamber (102); and a moisture sensor (9) is installed in the drying box (1).

4. The method for preparing a high-purity alumina ceramic green tape according to claim 3, characterized in that: A cylinder (7) is installed inside the moisturizing chamber (102), and the cylinder (7) is connected to the active plate (802) via a push-pull rod (810). A plurality of multi-stage heating plates (6) are installed at the bottom of the drying box (1), and exhaust fans (5) are installed on both the low-temperature chamber (101) and the high-temperature chamber (103).

5. The method for preparing a high-purity alumina ceramic green tape according to claim 4, characterized in that: A connecting rod (808) is installed on the driven plate (803), a sliding groove (809) is provided inside the connecting rod (808), a sliding block (811) is installed on the push-pull rod (810), the sliding block (811) is located inside the sliding groove (809) and slides, an electromagnetic suction cup (812) is installed inside the sliding groove (809), and the electromagnetic suction cup (812) adsorbs the sliding block (811).

6. The method for preparing a high-purity alumina ceramic green tape according to claim 5, characterized in that: A sealing frame (804) is installed on the driven plate (803), a moisture absorbing block (805) is installed on the active plate (802), and the sealing frame (804) covers the moisture absorbing block (805).

7. The method for preparing a high-purity alumina ceramic green tape according to claim 3, characterized in that: A sealing strip (813) is installed on the fixed plate (801) and the active plate (802), and the fixed plate (801) and the active plate (802) contact the top of the drying box (1) through the sealing strip (813) thereon.

8. The method for preparing a high-purity alumina ceramic green tape according to claim 3, characterized in that: The low-temperature pressure tank (304) is connected to the low-temperature chamber (101) via a low-temperature branch pipe (305), and the high-temperature pressure tank (301) is connected to the high-temperature chamber (103) via a high-temperature branch pipe (302), and one of the heads on the high-temperature branch pipe (302) is located in the moisturizing chamber (102).

9. The method for preparing a high-purity alumina ceramic green tape according to claim 1, characterized in that: The solvent is a mixture of anhydrous ethanol, butanone and n-butanol.

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