Glue discharging method of electronic ceramic green body

Abstract

The invention relates to the technical field of electronic ceramic green bodies, in particular to a glue discharging method of an electronic ceramic green body. Comprising the following steps: step 1, ball-milling raw materials, and carrying out tape casting to obtain a ceramic green body; 2, the ceramic green bodies are subjected to powder coating and stacked into a stack, and laminated green bodies are obtained; 3, in the nitrogen atmosphere, primary glue discharging is conducted on the laminated green body, and a primary glue-discharged green body is obtained; 4, in the nitrogen atmosphere, the primary degummed green body is subjected to secondary degummed, and a secondary degummed green body is obtained; 5, under the nitrogen atmosphere, high-temperature vacuum carbon removal is conducted on the secondary rubber-removed green body, and a high-temperature carbon-removed green body is obtained; 6, under the nitrogen atmosphere, the high-temperature carbon-removed green body is rapidly cooled; and obtaining the electronic ceramic body.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic ceramic green bodies, and specifically to a debinding method for electronic ceramic green bodies. Background Art

[0002] With the development of electronic ceramics towards high-density integration and high performance, among them, the debinding process in the preparation of high-performance electronic ceramic devices has attracted much attention. The core goal of the debinding process is to efficiently remove the organic binder and reduce carbon residue while maintaining the structural integrity of the green body.

[0003] Currently, the debinding time of electronic ceramics is generally 3 to 5 days, with a long debinding cycle and low efficiency; shortening the debinding time will cause incomplete decomposition of organic matter during debinding, and some oxygen will invade, which will not only lead to an increase in residual carbon in the electronic ceramic debinding sheet, but also cause an increase in oxygen content. The large residual carbon in the debinding sheet has an adverse effect during the sintering of the green body into porcelain, and the increase in oxygen content will cause a decrease in the thermal conductivity of the sintered ceramic.

[0004] Traditional binders mainly have the following problems in debinding: First, the decomposition temperature of traditional adhesives, polyvinyl butyral (PVB), is concentrated at 300 - 400 °C, with a low temperature matching degree with the debinding process, resulting in residual carbon and interface defects; second, the organic-inorganic interfacial dispersibility of traditional binders and inorganic powders is poor, resulting in easy cracking during the debinding process and affecting the finished product effect.

[0005] In summary, to solve the above problems, it is of great significance to study a debinding method for electronic ceramic green bodies. Summary of the Invention

[0006] The purpose of the present invention is to provide a debinding method for electronic ceramic green bodies to solve the problems raised in the above background art.

[0007] To solve the above technical problems, the present invention provides the following technical solutions:

[0008] A debinding method for electronic ceramic green bodies, comprising the following steps:

[0009] Step 1: Ball-mill the raw materials and then perform tape casting to obtain a ceramic green body;

[0010] Step 2: Apply powder to the ceramic green body and stack it into a stack to obtain a laminated green body;

[0011] Step 3: Under a nitrogen atmosphere, perform primary debinding on the laminated green body to obtain a primary debound green body;

[0012] Step 4: Under a nitrogen atmosphere, perform secondary debinding on the primary debound green body to obtain a secondary debound green body;

[0013] Step 5: Under a nitrogen atmosphere, subject the green body after secondary debinding to high-temperature vacuum decarburization to obtain a high-temperature decarburized green body;

[0014] Step 6: Under a nitrogen atmosphere, rapidly cool the high-temperature decarburized green body to obtain an electronic ceramic green body.

[0015] In a further embodiment, in Step 2, the specific process of powder coating and stacking into stacks is as follows: uniformly coat a layer of boron nitride on one side of the green body of the ceramic green body, and then stack them into stacks of 4 to 8 pieces to obtain a stacked green body.

[0016] In a further embodiment, the total debinding time of Steps 3 to 6 can be controlled within 24 hours.

[0017] More preferably, in Step 3, the specific parameters of the primary debinding are as follows: the vacuum degree is -0.9 to -0.8 MPa (relative to atmospheric pressure), for every 500 L of furnace volume, the nitrogen flow rate is 50 L / min to 100 L / min, the heating rate is in a gradient heating mode, that is, the heating rate from 30 to 180 °C is 0.95 to 1.05 °C / min, the heating rate from 180 to 240 °C is 0.2 to 0.3 °C / min, and the heating target is 235 to 245 °C.

[0018] More preferably, in Step 4, the specific parameters of the secondary debinding are as follows: the vacuum degree is -0.6 to -0.5 MPa (relative to atmospheric pressure), the nitrogen flow rate is 100 L / min to 200 L / min, the heating rate is 0.35 to 0.45 °C / min, and the heating target is 475 to 485 °C.

[0019] More preferably, in Step 5, the specific parameters of the high-temperature vacuum decarburization are as follows: the vacuum degree is -0.9 to -0.8 MPa (relative to atmospheric pressure), the nitrogen flow rate is 50 L / min to 100 L / min, the heating rate is 0.45 to 0.55 °C / min, and the heating target is 535 to 545 °C.

[0020] More preferably, in Step 6, the specific parameters of the rapid cooling are as follows: the nitrogen flow rate is 300 L / min to 400 L / min, the rapid cooling time is 4.5 to 5.5 hours, and the cooling target is 95 to 105 °C.

[0021] More preferably, in Step 1, the raw materials of the electronic ceramic green body include the following components: by mass, 60 to 70 parts of ceramic powder, 40 to 80 parts of solvent, 0.5 to 2 parts of dispersant, 8 to 10 parts of binder, 2 to 5 parts of composite additive, 1 to 3 parts of sintering aid, and 5 to 8 parts of plasticizer.

[0022] In a further embodiment, the ceramic powder includes one of silicon nitride, aluminum nitride, and silicon carbide.

[0023] In a further embodiment, the sintering aid includes, but is not limited to, magnesium oxide, zirconium oxide, titanium oxide, and β-Si3N4 seeds.

[0024] In a further embodiment, the plasticizer includes, but is not limited to, dibutyl phthalate and polyethylene glycol.

[0025] In a further embodiment, the solvent includes isopropyl alcohol and butyl acetate with a mass ratio of 1 to 1.5:1.

[0026] In a further embodiment, the dispersant includes, but is not limited to, triethyl phosphate and glyceryl trioleate.

[0027] Preferably, the binder is polyvinyl butyral (PVB).

[0028] Preferably, the binder is PVB-Si-COOH, and the preparation process of PVB-Si-COOH is as follows:

[0029] S1-1: Add vinyl acetate, dicyclopentadiene, and azobisisobutyronitrile to toluene, and react at 65 to 75 °C for 7 to 8 hours to obtain branched polyvinyl acetate; add the branched polyvinyl acetate and 0.95 to 1.05 mol / L dilute hydrochloric acid to a 40 to 50 wt% ethanol aqueous solution, and react at 60 to 80 °C for 4 to 6 hours to obtain branched polyvinyl alcohol.

[0030] S1-2: Add the branched polyvinyl alcohol to deionized water, add butyraldehyde and oxalic acid, react at 40 to 50 °C for 5 to 7 hours, add sodium hydroxide to adjust the pH to 6.9 to 7.1, then add 3-(2,3-epoxypropoxy)propyltrimethoxysilane and a 60 to 70 wt% ethanol aqueous solution, react at 50 to 70 °C for 4 to 6 hours, add acetic acid to adjust the pH to 5.9 to 6.1, filter, wash, and dry to obtain PVB-Si.

[0031] S1-3: Add PVB-Si, benzoyl peroxide, and maleic anhydride to N,N-dimethylformamide and react at 70 to 90 °C for 2 to 3 hours to obtain PVB-Si-COOH.

[0032] In a further embodiment, the PVB-Si is a branched polyvinyl butyral modified with a silane coupling agent; the PVB-Si-COOH is a branched polyvinyl butyral modified with a silane coupling agent and further modified with maleamide, and finally a substance with a carboxyl group.

[0033] In a further embodiment, the raw materials of the branched polyvinyl alcohol include the following components: by mass, 80 to 90 parts of vinyl acetate, 5 to 8 parts of dicyclopentadiene, 0.5 to 1 part of azobisisobutyronitrile, 150 to 200 parts of toluene, 0.5 to 2 parts of 0.95 to 1.05 mol / L dilute hydrochloric acid, and 100 to 200 parts of 40 to 50 wt% ethanol aqueous solution.

[0034] Preferably, the raw materials of the PVB-Si include the following components: by mass, 8 to 12 parts of branched polyvinyl alcohol, 50 to 60 parts of deionized water, 3 to 5 parts of butyraldehyde, 0.5 to 1 part of oxalic acid, 2 to 4 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, and 50 to 70 parts of 60 to 70 wt% ethanol aqueous solution;

[0035] The raw materials of the PVB-Si-COOH include the following components: by mass, 7 to 11 parts of PVB-Si, 0.5 to 1 part of benzoyl peroxide, 3 to 5 parts of maleic anhydride, and 50 to 60 parts of N,N-dimethylformamide.

[0036] Preferably, the preparation process of the composite additive is as follows:

[0037] S2-1: Mix ethylene-vinyl acetate copolymer (EVA) and polycaprolactone (PCL) according to a mass ratio of 1 to 2:1 to obtain an EVA / PCL copolymer;

[0038] S2-2: Add Tween-80 to the EVA / PCL copolymer according to a mass ratio of 1 to 2:3, stir for 20 to 30 min and ultrasonically disperse for 30 to 60 min to obtain the composite additive.

[0039] In a further embodiment, the EVA / PCL copolymer is a copolymer obtained by mixing ethylene-vinyl acetate copolymer (EVA) and polycaprolactone (PCL).

[0040] In a further embodiment, the content of VA in the ethylene-vinyl acetate copolymer (EVA) is 20%.

[0041] In the embodiment, through the synergy of PVB-Si-COOH and the composite additive, the dispersibility of the binder and the inorganic powder is enhanced. While reducing and shortening the debinding time, it can also ensure the decomposition of organic matter during debinding, has a high temperature matching degree with the debinding process, further reduces the carbon content and oxygen content, and improves the quality of the green body.

[0042] Among them, although branched-chain PVB can solve the problem of green cutting adhesion of multi-layer ceramics, the following problems still exist: First, the decomposition temperature of branched-chain PVB does not match the actual debinding process temperature, which will cause it to fail to start decomposition in the low-temperature section and burn violently in the high-temperature section, resulting in a significant increase in carbon content and oxygen content; Second, the distribution of polar groups in branched-chain PVB is uneven, and its dispersibility with inorganic powder is poor, prone to cracking, thus affecting product quality.

[0043] To solve the above problems, through further bifunctional modification (condensation grafting of siloxane and nucleophilic addition grafting of carboxyl group), a Si-O-M covalent bond is formed by grafting silane coupling agent, which can not only enhance the chemical binding force with inorganic powder, avoid pore defects caused by insufficient binding force during debinding, reduce the oxygen intrusion channel, but also improve the high-temperature stability and further reduce the carbon content and oxygen content; carboxyl groups are introduced to form hydrogen bond interaction with the EVA / PCL copolymer in the composite additive, further delaying the thermal diffusion of binder molecules.

[0044] Among them, the EVA / PCL copolymer in the composite additive (EVA / PCL / Tween-80) melts to form a continuous phase at the initial stage of debinding, adheres to the surface of the binder, produces a physical isolation effect to delay the thermal diffusion of binder molecules, postpones the initial decomposition temperature to the medium-temperature section, and avoids local overheating and concentrated combustion in the early stage; after the copolymer melts in the medium-temperature stage, it promotes the dissolution and discharge of decomposition products, shortens the debinding time while reducing the carbon and oxygen content, and improves product quality. Tween-80 is introduced to improve the interfacial dispersibility, reduce agglomeration, and thus reduce carbon residue.

[0045] Compared with the prior art, the beneficial effects of the present invention are:

[0046] (1) Using the method of vacuum compounded with nitrogen to discharge the PVB glue contained in the electronic ceramic;

[0047] (2) This method is simple and easy to implement, and can obtain an electronic ceramic blank with low carbon content and low oxygen content in a situation of greatly shortening the debinding time;

[0048] (3) In the scheme, through the "bifunctional modification + composite additive synergy" of PVB-Si-COOH and the composite additive, the dispersibility of the binder and the inorganic powder is enhanced. While reducing and shortening the debinding time, it can also ensure the decomposition of organic matter during debinding, with a high temperature matching degree with the debinding process, further reducing the carbon content and oxygen content, and improving the quality of the blank. Specific embodiments

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0050] It should be noted that the following parts are parts by mass, and there are no special restrictions on the manufacturers of raw materials involved in the present invention. Exemplarily, including: in the following embodiments, the ethylene-vinyl acetate copolymer has a CAS number of 24937-78-8, a VA content of 20%, and is purchased from Dongguan Taotao Plastic Raw Materials Co., Ltd.; the polycaprolactone has a CAS number of 24980-41-4; the Tween-80 has a CAS number of 9005-65-6.

[0051] In the following embodiments, it is particularly noted that:

[0052] (1) The total debinding time from step (primary debinding) to step (rapid cooling) is within 24 hours.

[0053] Embodiment 1: A debinding method for an electronic ceramic green body, comprising the following steps:

[0054] Step 1: Preparation of a composite additive: S1: Mix ethylene-vinyl acetate copolymer and polycaprolactone according to a mass ratio of 1.5:1 to obtain an EVA / PCL copolymer; S2: Add Tween-80 to the EVA / PCL copolymer according to a mass ratio of 1.5:3, stir for 30 min and ultrasonically disperse for 45 min to obtain a composite additive;

[0055] Step 2: Take 65 parts of ceramic powder silicon nitride, 60 parts of solvent isopropanol / butyl acetate (mass ratio of 1.2:1), 1.2 parts of triethyl phosphate, 9 parts of polyvinyl butyral, 3.5 parts of composite additive, 1.5 parts of magnesium oxide, and 6.5 parts of dibutyl phthalate, perform ball milling and then tape casting to obtain a ceramic green body;

[0056] Step 3: Uniformly coat a layer of boron nitride on one side of the ceramic green body, and then stack them into stacks of 6 pieces to obtain a laminated green body;

[0057] Step 4: Primary debinding (low-temperature vacuum debinding): Pump the pressure of the vacuum debinding furnace to -0.85 MPa (relative to atmospheric pressure). For every 500 L of furnace volume, the nitrogen flow rate is 75 L / min. Under this vacuum degree and nitrogen flow rate, heat up to 240 °C, with a heating rate of 1 °C / min from 140 °C and a heating rate of 0.25 °C / min from 210 °C to perform primary debinding on the laminated green body to obtain a primary debinding green body;

[0058] Step 5: Secondary debinding (debinding in nitrogen atmosphere): Pump the pressure of the vacuum debinding furnace to -0.55 MPa (relative to atmospheric pressure), with a nitrogen flow rate of 150 L / min. Under this vacuum and nitrogen flow rate, heat up to 480 °C at a heating rate of 0.4 °C / min to perform secondary debinding on the green body after primary debinding, obtaining a green body after secondary debinding;

[0059] Step 6: High-temperature vacuum decarburization: Pump the pressure of the vacuum debinding furnace to -0.85 MPa (relative to atmospheric pressure), with a nitrogen flow rate of 75 L / min. Under this vacuum and nitrogen flow rate, heat up to 540 °C at a heating rate of 0.5 °C / min to perform high-temperature vacuum decarburization on the green body after secondary debinding, obtaining a green body after high-temperature decarburization;

[0060] Step 7: Introduce a nitrogen atmosphere and rapidly cool the green body after high-temperature decarburization at a flow rate of 350 L / min to 100 °C within 5 h, obtaining an electronic ceramic green body.

[0061] Example 2: A debinding method for an electronic ceramic green body, comprising the following steps:

[0062] Step 1: Preparation of PVB-Si-COOH: S1: Add 85 parts of vinyl acetate, 6.5 parts of dicyclopentadiene, and 0.8 part of azobisisobutyronitrile to 180 parts of toluene, and react at 70 °C for 8 hours to obtain branched polyvinyl acetate; Add the branched polyvinyl acetate and 2 parts of 1 mol / L dilute hydrochloric acid to 150 parts of 45 wt% ethanol aqueous solution, and react at 80 °C for 6 hours to obtain branched polyvinyl alcohol; S2: Add 10 parts of branched polyvinyl alcohol to 55 parts of deionized water, add 4 parts of butyraldehyde and 0.7 part of oxalic acid, react at 45 °C for 6 hours, add sodium hydroxide to adjust the pH to 7.0, then add 3 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 60 parts of 65 wt% ethanol aqueous solution, react at 60 °C for 6 hours, add acetic acid to adjust the pH to 6.0, filter, wash, and dry to obtain PVB-Si; S3: Add 9 parts of PVB-Si, 0.8 part of benzoyl peroxide, and 4 parts of maleic anhydride to 55 parts of N,N-dimethylformamide, and react at 85 °C for 2.5 hours to obtain PVB-Si-COOH;

[0063] Step 2: Preparation of the composite additive: S1: Mix ethylene-vinyl acetate copolymer and polycaprolactone according to a mass ratio of 1.5:1 to obtain an EVA / PCL copolymer; S2: Add Tween-80 to the EVA / PCL copolymer according to a mass ratio of 1.5:3, stir for 30 min and ultrasonically disperse for 45 min to obtain the composite additive;

[0064] Step 3: Take 65 parts of silicon nitride ceramic powder, 60 parts of solvent isopropyl alcohol / butyl acetate (mass ratio 1.2:1), 1.2 parts of triethyl phosphate, 9 parts of PVB-Si-COOH, 3.5 parts of composite additive, 1.5 parts of magnesium oxide, and 6.5 parts of dibutyl phthalate. After ball milling, tape casting is carried out to obtain a green ceramic body;

[0065] Step 4: Uniformly coat a layer of boron nitride on one side of the green ceramic body, and then stack them into stacks of 6 pieces to obtain a laminated green body;

[0066] Step 5: Primary debinding (low-temperature vacuum debinding): Pump the pressure of the vacuum debinding furnace to -0.85 MPa (relative to atmospheric pressure). For every 500 L of furnace volume, the nitrogen flow rate is 75 L / min. Under this vacuum and nitrogen flow rate, heat up to 240 °C, with a heating rate of 1 °C / min from 140 °C and a heating rate of 0.25 °C / min from 210 °C to carry out primary debinding on the laminated green body to obtain a primary debound green body;

[0067] Step 6: Secondary debinding (nitrogen atmosphere debinding): Pump the pressure of the vacuum debinding furnace to -0.55 MPa (relative to atmospheric pressure), and the nitrogen flow rate is 150 L / min. Under this vacuum and nitrogen flow rate, heat up to 480 °C with a heating rate of 0.4 °C / min to carry out secondary debinding on the primary debound green body to obtain a secondary debound green body;

[0068] Step 7: High-temperature vacuum carbon removal: Pump the pressure of the vacuum debinding furnace to -0.85 MPa (relative to atmospheric pressure), and the nitrogen flow rate is 75 L / min. Under this vacuum and nitrogen flow rate, heat up to 540 °C with a heating rate of 0.5 °C / min to carry out high-temperature vacuum carbon removal on the secondary debound green body to obtain a high-temperature carbon-removed green body;

[0069] Step 8: Introduce a nitrogen atmosphere, and quickly cool the high-temperature carbon-removed green body to 100 °C within 5 h at a flow rate of 350 L / min to obtain an electronic ceramic green body.

[0070] Example 3: A debinding method for an electronic ceramic green body, comprising the following steps:

[0071] Step 1: Preparation of PVB-Si-COOH: S1: Add 85 parts of vinyl acetate, 6.5 parts of dicyclopentadiene, and 0.8 part of azobisisobutyronitrile to 180 parts of toluene, and react at 70 °C for 8 hours to obtain branched polyvinyl acetate; add the branched polyvinyl acetate and 2 parts of 1 mol / L dilute hydrochloric acid to 150 parts of 45 wt% ethanol aqueous solution, and react at 80 °C for 6 hours to obtain branched polyvinyl alcohol; S2: Add 10 parts of branched polyvinyl alcohol to 55 parts of deionized water, add 4 parts of butyraldehyde and 0.7 part of oxalic acid, react at 45 °C for 6 hours, adjust the pH to 7.0 with sodium hydroxide, then add 2 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 60 parts of 65 wt% ethanol aqueous solution, react at 60 °C for 6 hours, adjust the pH to 6.0 with acetic acid, filter, wash, and dry to obtain PVB-Si; S3: Add 7 parts of PVB-Si, 0.8 part of benzoyl peroxide, and 3 parts of maleic anhydride to 55 parts of N,N-dimethylformamide, and react at 85 °C for 2.5 hours to obtain PVB-Si-COOH;

[0072] Step 2: Preparation of composite additive: S1: Mix ethylene-vinyl acetate copolymer and polycaprolactone according to a mass ratio of 1:1 to obtain EVA / PCL copolymer; S2: Add Tween-80 to the EVA / PCL copolymer according to a mass ratio of 1:3, stir for 30 min and ultrasonically disperse for 45 min to obtain the composite additive;

[0073] Step 3: Take 60 parts of ceramic powder silicon nitride, 40 parts of solvent isopropyl alcohol / butyl acetate (mass ratio 1:1), 0.5 part of triethyl phosphate, 8 parts of PVB-Si-COOH, 2 parts of composite additive, 1 part of magnesium oxide, and 5 parts of dibutyl phthalate, perform ball milling and then tape casting to obtain a green ceramic body;

[0074] Step 4: Uniformly coat a layer of boron nitride on one side of the green ceramic body, and then stack them into stacks of 6 pieces to obtain a laminated green body;

[0075] Step 5: Primary debinding (low-temperature vacuum debinding): Pump the pressure of the vacuum debinding furnace to -0.85 MPa (relative to atmospheric pressure). For every 500 L of furnace volume, the nitrogen flow rate is 50 L / min. Under this vacuum degree and nitrogen flow rate, heat up to 240 °C at a heating rate of 1 °C / min for the temperature range from room temperature to 180 °C and 0.25 °C / min for the temperature range from 180 °C to 240 °C to perform primary debinding on the laminated green body to obtain a primary debound green body;

[0076] Step 6: Secondary debinding (debinding in nitrogen atmosphere): Pump the pressure of the vacuum debinding furnace to -0.55 MPa (relative to atmospheric pressure), with a nitrogen flow rate of 100 L / min. Under this vacuum and nitrogen flow rate, heat up to 480 °C at a heating rate of 0.4 °C / min to perform secondary debinding on the green body after the first debinding, obtaining a green body after secondary debinding;

[0077] Step 7: High-temperature vacuum decarburization: Pump the pressure of the vacuum debinding furnace to -0.85 MPa (relative to atmospheric pressure), with a nitrogen flow rate of 50 L / min. Under this vacuum and nitrogen flow rate, heat up to 540 °C at a heating rate of 0.5 °C / min to perform high-temperature vacuum decarburization on the green body after secondary debinding, obtaining a green body after high-temperature decarburization;

[0078] Step 8: Introduce a nitrogen atmosphere and rapidly cool the green body after high-temperature decarburization at a flow rate of 300 L / min to 100 °C within 5 h, obtaining an electronic ceramic green body.

[0079] Example 4: A method for debinding an electronic ceramic green body, comprising the following steps:

[0080] Step 1: Preparation of PVB-Si-COOH: S1: Add 85 parts of vinyl acetate, 6.5 parts of dicyclopentadiene, and 0.8 part of azobisisobutyronitrile to 180 parts of toluene, and react at 70 °C for 8 hours to obtain branched polyvinyl acetate; Add the branched polyvinyl acetate and 2 parts of 1 mol / L dilute hydrochloric acid to 150 parts of 45 wt% ethanol aqueous solution, and react at 80 °C for 6 hours to obtain branched polyvinyl alcohol; S2: Add 10 parts of branched polyvinyl alcohol to 55 parts of deionized water, add 4 parts of butyraldehyde and 0.7 part of oxalic acid, react at 45 °C for 6 hours, add sodium hydroxide to adjust the pH to 7.0, then add 4 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 60 parts of 65 wt% ethanol aqueous solution, react at 60 °C for 6 hours, add acetic acid to adjust the pH to 6.0, filter, wash, and dry to obtain PVB-Si; S3: Add 11 parts of PVB-Si, 0.8 part of benzoyl peroxide, and 5 parts of maleic anhydride to 55 parts of N,N-dimethylformamide, and react at 85 °C for 2.5 hours to obtain PVB-Si-COOH;

[0081] Step 2: Preparation of the composite additive: S1: Mix ethylene-vinyl acetate copolymer and polycaprolactone according to a mass ratio of 2:1 to obtain an EVA / PCL copolymer; S2: Add Tween-80 to the EVA / PCL copolymer according to a mass ratio of 2:3, stir for 30 min and ultrasonically disperse for 45 min to obtain the composite additive;

[0082] Step 3: Take 70 parts of silicon nitride ceramic powder, 80 parts of solvent isopropyl alcohol / butyl acetate (mass ratio of 1.5:1), 2 parts of triethyl phosphate, 10 parts of PVB-Si-COOH, 5 parts of composite additive, 3 parts of magnesium oxide, and 8 parts of dibutyl phthalate. After ball milling, tape casting is carried out to obtain a green ceramic body;

[0083] Step 4: Uniformly coat a layer of boron nitride on one side of the green ceramic body, and then stack them into stacks of 6 pieces to obtain a laminated green body;

[0084] Step 5: First debinding (low-temperature vacuum debinding): Pump the pressure of the vacuum debinding furnace to -0.85 MPa (relative to atmospheric pressure). For every 500 L of furnace volume, the nitrogen flow rate is 100 L / min. Under this vacuum degree and nitrogen flow rate, heat up to 240 °C, with a heating rate of 1 °C / min from 180 °C to 240 °C and a heating rate of 0.25 °C / min at 240 °C to conduct first debinding on the laminated green body to obtain a first-debound green body;

[0085] Step 6: Second debinding (nitrogen atmosphere debinding): Pump the pressure of the vacuum debinding furnace to -0.55 MPa (relative to atmospheric pressure), with a nitrogen flow rate of 200 L / min. Under this vacuum degree and nitrogen flow rate, heat up to 480 °C, with a heating rate of 0.4 °C / min to conduct second debinding on the first-debound green body to obtain a second-debound green body;

[0086] Step 7: High-temperature vacuum decarburization: Pump the pressure of the vacuum debinding furnace to -0.85 MPa (relative to atmospheric pressure), with a nitrogen flow rate of 100 L / min. Under this vacuum degree and nitrogen flow rate, heat up to 540 °C, with a heating rate of 0.5 °C / min to conduct high-temperature vacuum decarburization on the second-debound green body to obtain a high-temperature decarburized green body;

[0087] Step 8: Introduce a nitrogen atmosphere, and quickly cool the high-temperature decarburized green body to 100 °C within 5 h at a flow rate of 400 L / min to obtain an electronic ceramic green body.

[0088] Comparative Example 1: Based on Example 1, in Step 4, no vacuum is pumped, and the rest of the process remains unchanged. It is adjusted to:

[0089] Step 4: First debinding (low-temperature vacuum debinding): For every 500 L of furnace volume, the nitrogen flow rate is 75 L / min. Heat up to 240 °C, with a heating rate of 1 °C / min from 140 °C to 210 °C and a heating rate of 0.25 °C / min at 210 °C to conduct first debinding on the laminated green body to obtain a first-debound green body.

[0090] Comparative Example 2: Based on Example 1, in Step 5, no vacuum is pumped, and the rest of the process remains unchanged. It is adjusted to:

[0091] Step 5: Secondary debinding (debinding in nitrogen atmosphere): With a nitrogen flow rate of 150 L / min, heat up to 480 °C at a heating rate of 0.4 °C / min to perform secondary debinding on the green body after primary debinding, obtaining a green body after secondary debinding.

[0092] Comparative Example 3: Based on Example 1, in Step 6, no vacuum pumping is performed, and the remaining processes remain unchanged, adjusted to:

[0093] Step 6: High-temperature vacuum decarburization: With a nitrogen flow rate of 75 L / min, heat up to 540 °C at a heating rate of 0.5 °C / min to perform high-temperature vacuum decarburization on the green body after secondary debinding, obtaining a green body after high-temperature decarburization.

[0094] Comparative Example 4: Based on Example 1, the nitrogen atmosphere in Step 5 is adjusted to an air atmosphere, and the remaining processes remain unchanged, adjusted to:

[0095] Step 5: Secondary debinding (debinding in nitrogen atmosphere): Pump the pressure of the vacuum debinding furnace to -0.55 MPa (relative to atmospheric pressure), with an air flow rate of 150 L / min. Under this vacuum degree and air flow rate, heat up to 480 °C at a heating rate of 0.4 °C / min to perform secondary debinding on the green body after primary debinding, obtaining a green body after secondary debinding.

[0096] Comparative Example 5: Based on Example 2, the composite additive is adjusted to ethylene-vinyl acetate copolymer, and the remaining processes remain unchanged, adjusted to:

[0097] Step 2: Take 65 parts of silicon nitride ceramic powder, 60 parts of solvent isopropyl alcohol / butyl acetate (mass ratio of 1.2:1), 1.2 parts of triethyl phosphate, 9 parts of PVB-Si-COOH, 3.5 parts of ethylene-vinyl acetate copolymer, 1.5 parts of magnesium oxide, and 6.5 parts of dibutyl phthalate. After ball milling, perform tape casting to obtain a ceramic green body.

[0098] Comparative Example 6: Based on Example 2, PVB-Si-COOH is adjusted to branched PVB, and the remaining processes remain unchanged, adjusted to:

[0099] Step 1: Preparation of branched PVB: S1: Add 85 parts of vinyl acetate, 6.5 parts of dicyclopentadiene, and 0.8 part of azobisisobutyronitrile to 180 parts of toluene, and react at 70 °C for 8 hours to obtain branched polyvinyl acetate; add the branched polyvinyl acetate and 2 parts of 1 mol / L dilute hydrochloric acid to 150 parts of 45 wt% ethanol aqueous solution, and react at 80 °C for 6 hours to obtain branched polyvinyl alcohol; S2: Add 10 parts of branched polyvinyl alcohol to 55 parts of deionized water, add 4 parts of butyraldehyde and 0.7 part of oxalic acid, react at 45 °C for 6 hours, add sodium hydroxide to adjust the pH to 6.0, filter, wash, and dry to obtain branched PVB;

[0100] Step 2: Preparation of the composite additive: S1: Mix ethylene-vinyl acetate copolymer and polycaprolactone according to a mass ratio of 1.5:1 to obtain an EVA / PCL copolymer; S2: Add Tween-80 to the EVA / PCL copolymer according to a mass ratio of 1.5:3, stir for 30 min and ultrasonically disperse for 45 min to obtain the composite additive;

[0101] Step 3: Take 65 parts of silicon nitride ceramic powder, 60 parts of solvent isopropyl alcohol / butyl acetate (mass ratio 1.2:1), 1.2 parts of triethyl phosphate, 9 parts of branched PVB, 3.5 parts of the composite additive, 1.5 parts of magnesium oxide, and 6.5 parts of dibutyl phthalate, ball mill them and then perform tape casting to obtain a green ceramic body.

[0102] Comparative Example 7: Based on Example 2, adjust the composite additive to Tween-80, with the remaining processes unchanged, and adjust to:

[0103] Step 2: Take 65 parts of silicon nitride ceramic powder, 60 parts of solvent isopropyl alcohol / butyl acetate (mass ratio 1.2:1), 1.2 parts of triethyl phosphate, 9 parts of PVB-Si-COOH, 3.5 parts of Tween-80, 1.5 parts of magnesium oxide, and 6.5 parts of dibutyl phthalate, ball mill them and then perform tape casting to obtain a green ceramic body.

[0104] Comparative Example 8: Based on Example 2, adjust PVB-Si-COOH to PVB-Si, with the remaining processes unchanged, and adjust to:

[0105] Step 1: Preparation of PVB-Si: S1: Add 85 parts of vinyl acetate, 6.5 parts of dicyclopentadiene, and 0.8 part of azobisisobutyronitrile to 180 parts of toluene, react at 70 °C for 8 hours to obtain branched polyvinyl acetate; add the branched polyvinyl acetate and 2 parts of 1 mol / L dilute hydrochloric acid to 150 parts of 45 wt% ethanol aqueous solution, react at 80 °C for 6 hours to obtain branched polyvinyl alcohol; S2: Add 10 parts of branched polyvinyl alcohol to 55 parts of deionized water, add 4 parts of butyraldehyde and 0.7 part of oxalic acid, react at 45 °C for 6 hours, adjust the pH to 7.0 with sodium hydroxide, then add 3 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 60 parts of 65 wt% ethanol aqueous solution, react at 60 °C for 6 hours, adjust the pH to 6.0 with acetic acid, filter, wash, and dry to obtain PVB-Si;

[0106] Step 2: Preparation of the composite additive: S1: Mix ethylene-vinyl acetate copolymer and polycaprolactone according to a mass ratio of 1.5:1 to obtain an EVA / PCL copolymer; S2: Add Tween-80 to the EVA / PCL copolymer according to a mass ratio of 1.5:3, stir for 30 min and ultrasonically disperse for 45 min to obtain the composite additive;

[0107] Step 3: Take 65 parts of silicon nitride ceramic powder, 60 parts of solvent isopropyl alcohol / butyl acetate (mass ratio 1.2:1), 1.2 parts of triethyl phosphate, 9 parts of PVB-Si, 3.5 parts of composite additive, 1.5 parts of magnesium oxide, and 6.5 parts of dibutyl phthalate. After ball milling, tape casting is carried out to obtain a green ceramic body.

[0108] Detection experiment 1: For the electronic ceramic green bodies prepared in Examples 1-2 and Comparative Examples 1-8, their carbon content was detected: Using a carbon-sulfur analyzer, 5 test green bodies were taken from Examples 1-2 and Comparative Examples 1-8 respectively to measure the carbon content, and the maximum and minimum values were removed. The results are shown in Table 1;

[0109]

[0110] Table 1

[0111] Result analysis: According to the data analysis in Table 1, it can be seen that by using the debinding method of vacuum composite nitrogen in the present invention, an electronic ceramic debinding film with a low carbon content can be obtained with a greatly shortened debinding time, and the effect is excellent. From the data of Comparative Example 5, it can be known that ethylene-vinyl acetate copolymer (single additive) cannot exert a synergistic effect, and the debinding effect is the worst with the most carbon residue; from the data of Comparative Example 6, it can be known that branched PVB is not sufficiently modified, and the debinding performance is poor with a high carbon content; from the data of Comparative Example 7, it can be known that the use of Tween-80 alone has a worse debinding effect than the composite additive, but is slightly better than ethylene-vinyl acetate copolymer (single additive); from the data of Comparative Example 8, it can be known that PVB-Si has silicon oxy group modification, and the debinding performance is better than that of branched PVB, and the carbon content is relatively low.

[0112] Detection experiment 2: For the electronic ceramic green bodies prepared in Examples 1-2 and Comparative Examples 1-8, their oxygen content was detected: Using an oxygen-nitrogen analyzer, 5 test green bodies were taken from Examples 1-2 and Comparative Examples 1-8 respectively to measure the oxygen content, and the maximum and minimum values were removed. The results are shown in Table 2;

[0113]

[0114] Table 2

[0115] Result analysis: It can be seen from the data analysis in Table 2 that the results show that the debinding method using the vacuum composite nitrogen in the present invention can control the oxygen content of the green body at a relatively low level while greatly shortening the debinding time, with remarkable effects. From the data of Comparative Example 5, it can be known that the debinding effect is poor and there is a lot of residual organic components, and the oxygen element contained therein will also be relatively more; from the data of Comparative Example 6, it can be known that the branched PVB is not fully debound and the oxygen content is relatively high; from the data of Comparative Example 7, it can be known that the debinding effect of Tween-80 is not as good as that of the composite additive and the oxygen content is relatively high; from the data of Comparative Example 8, it can be known that PVB-Si has certain debinding advantages and the oxygen content is relatively low.

[0116] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A method for debinding an electronic ceramic body, characterized in that: The following steps are involved: Step 1: ball-milling the raw material and then tape-casting to obtain a ceramic green body; Step 2: Powdering the ceramic green body and stacking them into a stack to obtain a laminated green body; Step 3: Under a nitrogen atmosphere, the laminated green body is subjected to a debinding process to obtain a primary debinding green body; Step 4: Under a nitrogen atmosphere, the primary debinding green body is subjected to secondary debinding to obtain a secondary debinding green body; Step 5: Under a nitrogen atmosphere, the secondary debinding green body is subjected to high-temperature vacuum decarburization to obtain a high-temperature decarburized green body; Step 6: In a nitrogen atmosphere, the high-temperature decarbonized green body is rapidly cooled to obtain an electronic ceramic body.

2. The method for debinding an electronic ceramic body according to claim 1, characterized in that: In step 3, the specific parameters of the primary debinding are: vacuum degree is -0.9 to -0.8 MPa, nitrogen flow rate is 50 L / min to 100 L / min for every 500 L furnace volume, heating rate is in a gradient heating mode, i.e., heating rate at 30 to 180 ° C is 0.95 to 1.05 ° C / min, heating rate at 180 to 240 ° C is 0.2 to 0.3 ° C / min, and heating target is 235 to 245 ° C.

3. The method for debinding an electronic ceramic body according to claim 1, characterized in that: In step 4, the specific parameters of the secondary debinding are: vacuum degree of -0.6 to -0.5 MPa, nitrogen flow rate of 100 L / min to 200 L / min, heating rate of 0.35 to 0.45°C / min, and heating target of 475 to 485°C.

4. The method for debinding an electronic ceramic body according to claim 1, characterized in that: In step 5, the specific parameters of the high-temperature vacuum decarbonization are: vacuum degree of -0.9 to -0.8 MPa, nitrogen flow rate of 50 L / min to 100 L / min, heating rate of 0.45 to 0.55 °C / min, and heating target of 535 to 545 °C.

5. The method for debinding an electronic ceramic body according to claim 1, characterized in that: In step 6, the specific parameters of the rapid cooling are: nitrogen flow rate is 300L / min to 400L / min, rapid cooling time is 4.5 to 5.5 hours, and the temperature reduction target is 95 to 105°C.

6. The method for debinding an electronic ceramic body according to claim 1, characterized in that: In step 1, the raw materials of the electronic ceramic body include the following components: by mass, 60 to 70 parts of ceramic powder, 40 to 80 parts of solvent, 0.5 to 2 parts of dispersant, 8 to 10 parts of binder, 2 to 5 parts of composite additives, 1 to 3 parts of sintering aid, and 5 to 8 parts of plasticizer.

7. The method for debinding an electronic ceramic body according to claim 6, characterized in that: The binder is polyvinyl butyral.

8. The method for debinding an electronic ceramic body according to claim 6, characterized in that: The binder is PVB-Si-COOH, and the preparation process of PVB-Si-COOH is as follows: S1-1: Add vinyl acetate, dicyclopentadiene, and azobisisobutyronitrile to toluene, and react at 65-75° C. for 7-8 hours to obtain branched polyvinyl acetate; add branched polyvinyl acetate and 0.95-1.05 mol / L dilute hydrochloric acid to 40-50 wt% ethanol aqueous solution, and react at 60-80° C. for 4-6 hours to obtain branched polyvinyl alcohol; S1-2: adding branched polyvinyl alcohol to deionized water, adding butyraldehyde and oxalic acid, reacting at 40-50° C. for 5-7 hours, adding sodium hydroxide to adjust the pH to 6.9-7.1, then adding 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 60-70 wt% ethanol aqueous solution, reacting at 50-70° C. for 4-6 hours, adding acetic acid to adjust the pH to 5.9-6.1, filtering, washing, and drying to obtain PVB-Si; S1-3: PVB-Si, benzoyl peroxide and maleic anhydride are added to N,N-dimethylformamide and reacted at 70-90° C. for 2-3 hours to obtain PVB-Si-COOH.

9. The debinding method for an electronic ceramic body according to claim 8 is characterized in that: The raw materials of the PVB-Si include the following components: 8 to 12 parts by mass of branched polyvinyl alcohol, 50 to 60 parts by mass of deionized water, 3 to 5 parts by mass of butyraldehyde, 0.5 to 1 part by mass of oxalic acid, 2 to 4 parts by mass of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, and 50 to 70 parts by mass of 60 to 70 wt% ethanol aqueous solution; The raw materials of the PVB-Si-COOH include the following components: 7 to 11 parts of PVB-Si, 0.5 to 1 part of benzoyl peroxide, 3 to 5 parts of maleic anhydride, and 50 to 60 parts of N,N-dimethylformamide, calculated by mass.

10. The debinding method for an electronic ceramic body according to claim 6 is characterized in that: The preparation process of the composite additive is as follows: S2-1: mixing ethylene-vinyl acetate copolymer and polycaprolactone in a mass ratio of 1 to 2:1 to obtain an EVA / PCL copolymer; S2-2: Tween-80 was added to the EVA / PCL copolymer in a mass ratio of 1 to 2:3, stirred for 20 to 30 minutes and ultrasonically dispersed for 30 to 60 minutes to obtain a composite additive.

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