A heater platen and method for producing liquid crystal glass substrates / cover plates

Abstract

The application provides a heater furnace tray and method for producing liquid crystal glass substrate / cover plate, and the specific steps are as follows: S1, mixing high-purity alumina powder mixture, organic binder and water to obtain slurry by heating; S2, injecting the slurry into a mold under pressure, keeping pressure, demolding and repairing to obtain a furnace tray blank; when injecting the slurry, the injection pressure is 0.8-1.0 MPa, and the slurry temperature is 40-50 DEG C; S3, sintering the furnace tray blank twice to obtain an alumina ceramic heating furnace tray. The application can reduce production cost and manufacturing period by using the injection molding and sintering method.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of liquid crystal glass substrate / cover plate production equipment, and particularly relates to a heater furnace plate for producing liquid crystal glass substrates / cover plates and a method. BACKGROUND

[0002] In the production process of liquid crystal glass substrates and cover plates, a heater is needed to generate heat in the furnace to ensure stable temperature and thermal field in the furnace. The temperature in the furnace can reach 1100 DEG C. Since the quality requirements of the substrate glass and cover plate glass for the glass are very high, the original furnace plate is made of alumina ceramic bricks by CNC processing. Since the number of furnace plates required is large, the structure of the furnace plate is complex, the hardness of the alumina ceramic bricks is large, the Rockwell hardness is HRA80-90, which is only second to diamond, the CNC processing forming method takes too long time, the processing cost is too large, and the equipment investment cost is increased. SUMMARY

[0003] In order to solve the problems in the prior art, the application provides a heater furnace plate for producing liquid crystal glass substrates / cover plates and a method, which is prepared by slip casting and sintering, so that the production cost and manufacturing period can be reduced.

[0004] To achieve the above object, the application provides the following technical scheme: a preparation method of a heater furnace plate for producing liquid crystal glass substrates / cover plates, and the specific steps are as follows:

[0005] S1: mixing, heating and obtaining a slurry by mixing a high-purity alumina powder mixture, an organic binder and water;

[0006] S2: injecting the slurry into a mold under pressure, keeping pressure, demolding and finishing to obtain a furnace plate blank. When the slurry is injected, the injection pressure is 0.8 MPa-1.0 MPa, and the slurry temperature is 40 DEG C-50 DEG C.

[0007] S3: sintering the furnace plate blank twice to obtain an alumina ceramic heating furnace plate.

[0008] Further, in S1, the mass percentage content of the high-purity alumina powder in the high-purity alumina powder mixture is greater than 97%, the purity of the high-purity alumina powder is greater than 99.9%, and the particle size of the high-purity alumina powder is 80-120 mesh.

[0009] Further, in S1, the mass ratio of the high-purity alumina powder mixture, water and the organic binder is 80%-90%:9%-15%:1%-5%, and the heating temperature is 150 DEG C-200 DEG C.

[0010] Further, in S1, the binder is polyvinyl alcohol, methyl cellulose or water-soluble paraffin.

[0011] Further, in S2, the pressure maintaining time is 10-30 min.

[0012] Further, in S2, the mold shape is set according to the shape and shrinkage ratio of the alumina ceramic heating furnace tray, and is prepared by using a mold steel or an alloy steel, and the mold is required to be non-deformable and the inner cavity is smooth and free of rust.

[0013] Further, in S3, the furnace tray blank is subjected to primary sintering, specifically, the temperature is raised to 300-400 DEG C within 12 h, and the holding time is 12-24 h.

[0014] Further, in S3, the furnace tray blank is subjected to secondary sintering, specifically, the temperature is raised to 1600-1800 DEG C within 20-24 h, and the holding time is 12-24 h.

[0015] Further, the shrinkage ratio of the prepared heating furnace tray is 1.05-1.055.

[0016] The application also provides a heating furnace tray prepared by the above method.

[0017] Compared with the prior art, the application has at least the following beneficial effects:

[0018] The application provides a preparation method of a heating furnace tray for producing liquid crystal glass substrate / cover plate, which selects mold injection molding, the mold can be repeatedly used, the production cost is reduced, super-fine alumina powder is selected, the porosity is small, atomic diffusion occurs in the sintering process, the porosity is more easily filled, and it is beneficial to sintering of the heating furnace tray with a dense surface and smooth surface; appropriate sintering temperature is selected, which is beneficial to crystal growth, grain growth, grain boundary movement, and continuous diffusion of substances on the grain boundary to the porosity, so that the porosity is gradually eliminated, and finally the dense alumina sintering furnace tray is obtained.

[0019] The application subjects the furnace tray blank to twice sintering, wherein the primary sintering temperature is selected to be 300-400 DEG C, which is beneficial to removal of the binder, the binder is all gasified and volatilized at the temperature range, with the increase of the temperature, the binder in the blank is melted and separated out, and finally all is gasified and volatilized and discharged together with the flue gas; in the secondary sintering, with the continuous increase of the temperature, atomic diffusion is intensified, the porosity is reduced, the indirect contact between the particles is changed into surface contact, the porosity is reduced, the connected porosity becomes closed and is distributed in isolation; the grain boundary appears between the particles, the grain boundary moves, and the grain grows. The dense and hard alumina heating furnace tray is obtained through high-temperature sintering. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 、 2 It is a structure schematic diagram of the heating furnace tray for producing liquid crystal glass substrate / cover plate.

[0021] Figure 3 The mold structure diagram for the heating furnace plate for producing liquid crystal glass substrate / cover plate of the present application;

[0022] Figure 4 The mold outer mold structure diagram for the heating furnace plate for producing liquid crystal glass substrate / cover plate of the present application;

[0023] Figure 5 The preparation method flow for the heating furnace plate for producing liquid crystal glass substrate / cover plate of the present application;

[0024] In the drawing: 1. heating wire groove; 2. fixing hole; 3. wire passing hole; 4. edge covering groove; 5. inner mold; 6. handle; 7. screw hole; 8. outer mold; 9. edge covering groove plug; 10. grouting hole; 11. wire passing hole plug column; 12. wire tying hole plug column; 13. screw. DETAILED DESCRIPTION

[0025] The present application will be further described below in combination with the drawing and specific embodiments.

[0026] As Figures 1-2 shown, the present application provides a heating furnace plate for producing liquid crystal glass substrate / cover plate, which is made of high-purity alumina material, and is provided with a heating wire groove 1 for installing a heating wire, a wire passing hole 3 for passing the heating wire, a fixing hole for fixing the heating wire, a furnace plate edge covering groove 4, which is used for experimental test observation and replaces the original CNC processing formed furnace plate for use on the machine, and does not cause secondary pollution of volatile matter to the glass plate, and the process is stable during production, and the product quality is excellent. The mold grouting forming is adopted, and secondary firing is performed, and hundreds or thousands of pieces can be made at one time, the cost is saved by about 60%, and the time is saved by about 2 / 3, so that the furnace plate has the advantages of high hardness, high temperature resistance, corrosion resistance, wear resistance, electrical insulation, uniform heat conduction, oxidation resistance, alkali metal corrosion resistance, and stable chemical properties.

[0027] As Figure 5 shown, the production method of the above heating furnace plate specifically includes the following steps:

[0028] 1. Mold making:

[0029] Because the liquid crystal glass substrate and cover plate have very high requirements on glass quality, other impurities cannot be introduced to cause secondary pollution to the glass strip during production, so the requirements on the furnace plate and furnace plate mold are also very high, and the mold material should be selected from high-strength alloy steel, such as 1Cr13, 1Cr17, SUS304, etc., which is not easy to rust.

[0030] As Figures 3-4As shown, the stove plate mold comprises an outer mold 8 and an inner mold 5, the outer mold 8 is provided with a handle for facilitating demolding and carrying, and screw holes 7 fixed with the inner mold 5. The inner mold 5 is provided with a grouting hole 10, a wire passing hole plug 11, a wire plugging hole 12, a rim slot plug 9, and a screw hole 13 fixed with the inner mold 5.

[0031] Preferably, the mold should not be deformed, and the inner cavity should be smooth and free of rust;

[0032] Preferably, the shrinkage ratio of the stove plate should be considered in the design of the mold, and the shrinkage ratio of the stove plate made of this material is 1.05-1.055 after sintering.

[0033] 2. Ingredients:

[0034] Mix high-purity alumina powder with other raw materials and stir well to obtain a mixture.

[0035] The purity of high-purity alumina powder is required to be above 99.9%, the mass percentage of high-purity alumina powder in the mixture is greater than 97%, the raw materials are superfine crushed and the particle size is consistent, and the particle size is between 80-120 meshes.

[0036] The other raw materials are white corundum sand or talc powder;

[0037] 3. Slurry preparation:

[0038] During slurry preparation, water is used as a solvent medium, the prepared mixture is dissolved in water, and an organic binder is introduced, and then heated and stirred fully at a temperature of 150-200℃ to obtain a slurry.

[0039] Preferably, the mass ratio of high-purity alumina powder mixture, water, and organic binder is 80%-90%:9%-15%:1%-5%;

[0040] Preferably, the slurry preparation process should be fully stirred and mixed uniformly to remove air bubbles in the slurry; the temperature and viscosity of the slurry should be strictly controlled, the slurry heating temperature should be adjusted according to the environmental temperature, and the temperature and viscosity of the mold entering slurry should be consistent to facilitate the flow and grouting of the slurry.

[0041] Preferably, the binder uses PVA (polyvinyl alcohol), methyl cellulose, and water-soluble paraffin.

[0042] 4. Slurry casting:

[0043] The mixed slurry is injected into the prepared mold through the outer mold injection port by using a pressure pump. The injection pressure pump is equipped with a pressure gauge, and the injection pressure is selected to be 0.8-1.0 MPa. The slurry temperature during injection is 40-50 DEG C, and the pressure maintaining time is 10-30 min each time, so as to ensure the compaction of the blank and obtain the furnace plate blank.

[0044] Preferably, the mold is checked for deformation before injection, and the inner cavity of the mold is smooth and free of rust. In order to facilitate demolding, the inner surface of the mold is coated with a layer of lubricating grease before injection. Before blanking by injection, the inner and outer molds are assembled and fixed firmly, and the mold is fixed as a whole on the desktop or rack to avoid the mold from moving around during pressure injection.

[0045] 5. Demolding:

[0046] The furnace plate blank made by injection is separated from the mold. The mold should be cooled sufficiently before demolding, and the demolding temperature is less than 30 DEG C, so as to ensure that the furnace plate blank reaches a certain hardness during demolding. Generally, a low-temperature air-conditioned room or the mold is placed in flowing cooling water.

[0047] The mold fixing screws around the mold should be loosened during demolding, and the mold should not be knocked with brute force to prevent the mold and the blank from being deformed or broken. After demolding, the boss at the injection port on the back of the blank is cut off with a blade to make it flush with the large surface, and the made blank should be placed in a flat and clean place, and the surface should not be contaminated.

[0048] 6. First sintering:

[0049] The first sintering is mainly for the removal of the binder, such as the gasification and volatilization of paraffin at 250-400 DEG C. With the increase of temperature, the paraffin in the blank melts and precipitates, and finally all gasifies and volatilizes with the flue gas.

[0050] In order to fully remove the paraffin binder, the first sintering temperature is selected to be increased to 300-400 DEG C within 12 h, and the holding time is 12-24 h.

[0051] 7. Second sintering:

[0052] The second sintering temperature is higher than the first sintering temperature. The second sintering is to move the internal grain boundary, continue to grow the grain, and continuously diffuse the substances on the grain boundary to the pores, so as to gradually reduce and eliminate the pores, and obtain the dense and hard alumina ceramic furnace plate through high-temperature sintering.

[0053] In order to obtain a qualified furnace plate, the second sintering temperature is selected to be increased to 1600-1800 DEG C within 20-24 h, and the holding time is 12-24 h, and then gradually cooled.

[0054] The temperature in the sintering process cannot be increased too fast, and the fast temperature increase cannot make the crystal grow symmetrically, and easily forms crystal defects, causes the internal pore defects, the sintering temperature cannot be too high, and the holding time cannot be too long, so that the crystal is excessively grown, the crystal is coarsened, the binding force between the crystals is weakened, and the mechanical strength of the furnace plate is affected.

[0055] The furnace plate and the manufacturing method are not limited to be used in the production of liquid crystal glass substrates and cover plate equipment, and can cover the protection for producing any electronic glass equipment.

[0056] Embodiment 1

[0057] The application provides a preparation method of a heater furnace plate for producing liquid crystal glass substrates / cover plates, and specific steps are as follows:

[0058] S1, high-purity alumina powder and white corundum sand are mixed to obtain a mixture, and the mass percentage of the high-purity alumina powder in the mixture is greater than 97 %;

[0059] S2, when slurry is prepared, water is used as a solvent medium, the prepared mixture is dissolved in water, PVA is introduced, and the mixture is uniformly mixed under the condition of heating and fully stirring at 200 DEG C to obtain a slurry; the mass ratio of the high-purity alumina powder mixture, water and PVA is 80 %: 15 %: 5 %;

[0060] S3, the uniformly mixed slurry is injected into a previously prepared mold through an external mold injection port by using a pressure pump, the injection pressure pump is provided with a pressure gauge, the injection pressure is 1.0 Mpa, the slurry temperature is 50 DEG C during injection, the pressure holding time is 30 min, a furnace plate blank is obtained, and the injection prepared furnace plate blank is separated from the mold.

[0061] S4, the furnace plate blank is sintered once, the sintering temperature is selected to be increased to 400 DEG C within 12 h, and the holding time is 24 h.

[0062] S5, the furnace plate in S4 is sintered twice, the sintering temperature is selected to be increased to 1800 DEG C within 24 h, the holding time is 24 h, and the furnace plate is gradually cooled to obtain a qualified furnace plate.

[0063] Embodiment 2

[0064] The application provides a preparation method of a heater furnace plate for producing liquid crystal glass substrates / cover plates, and specific steps are as follows:

[0065] S1, high-purity alumina powder and white corundum sand are mixed to obtain a mixture, and the mass percentage of the high-purity alumina powder in the mixture is greater than 97 %;

[0066] S2, water is used as solvent medium when preparing slurry, the prepared mixture is dissolved in water, water-soluble paraffin is introduced, heated at 180 DEG C, fully stirred, uniformly mixed, and slurry is obtained; the mass ratio of high-purity alumina powder mixture, water and methyl cellulose is 90%:9%:1%;

[0067] S3, a pressure pump is selected to inject the uniformly mixed slurry into a previously prepared mold from the outer mold injection port, the injection pressure pump is equipped with a pressure gauge, the injection pressure is 0.9 MPa, the slurry temperature is 45 DEG C during injection, the pressure holding time is 20 min, a furnace tray blank is obtained, and the injection prepared furnace tray blank is separated from the mold.

[0068] S4, the furnace tray blank is sintered once, the sintering temperature is selected to be increased to 350 DEG C within 12 h, and the holding time is 12 h.

[0069] S5, the furnace tray of S4 is sintered twice, the sintering temperature is selected to be increased to 1700 DEG C within 12 h, the holding time is 12 h, and the furnace tray is gradually cooled to obtain a qualified furnace tray.

[0070] Example 3

[0071] The application provides a preparation method of a heater furnace tray for producing liquid crystal glass substrate / cover plate, and the specific steps are as follows:

[0072] S1, high-purity alumina powder and talc powder are mixed to obtain a mixture, and the mass percentage of high-purity alumina powder in the mixture is greater than 97%;

[0073] S2, water is used as solvent medium when preparing slurry, the prepared mixture is dissolved in water, water-soluble paraffin is introduced, heated at 180 DEG C, fully stirred, uniformly mixed, and slurry is obtained; the mass ratio of high-purity alumina powder mixture, water and methyl cellulose is 90%:9%:1%;

[0074] S3, a pressure pump is selected to inject the uniformly mixed slurry into a previously prepared mold from the outer mold injection port, the injection pressure pump is equipped with a pressure gauge, the injection pressure is 0.9 MPa, the slurry temperature is 45 DEG C during injection, the pressure holding time is 20 min, a furnace tray blank is obtained, and the injection prepared furnace tray blank is separated from the mold.

[0075] S4, the furnace tray blank is sintered once, the sintering temperature is selected to be increased to 350 DEG C within 12 h, and the holding time is 12 h.

[0076] S5, the furnace tray of S4 is sintered twice, the sintering temperature is selected to be increased to 1700 DEG C within 12 h, the holding time is 12 h, and the furnace tray is gradually cooled to obtain a qualified furnace tray.

Claims

1. A method for preparing a heater tray for producing liquid crystal glass substrates / cover plates, characterized in that, The specific steps are as follows: S1 involves mixing high-purity alumina powder, organic binder, and water, and then heating the mixture to obtain a slurry. S2 injects the slurry into the mold under pressure, holds the pressure, demolds, and shapes it to obtain the furnace tray blank. During slurry injection, the injection pressure is 0.8Mpa-1.0Mpa, the slurry temperature is 40℃~50℃, and the holding time is 10min~30min. S3 involves two sintering processes on the furnace plate blank to obtain an alumina ceramic heating furnace plate. In S1, the high-purity alumina powder mixture contains a high-purity alumina powder with a mass percentage greater than 97%, a purity of over 99.9%, and a particle size of 80-120 mesh. In S1, the mass ratio of high-purity alumina powder mixture, water, and organic binder is 80%~90%: 9%~15%: 1%~5%; the heating temperature is 150℃~200℃. In S3, the furnace plate blank is sintered once, specifically: the temperature is raised to 300℃~400℃ within 12 hours, and the holding time is 12~24 hours. In S3, the furnace plate blank undergoes secondary sintering, specifically by raising the temperature to 1600℃~1800℃ within 20h~24h and holding it at that temperature for 12~24h.

2. The method for preparing a heater tray for producing liquid crystal glass substrates / cover plates according to claim 1, characterized in that, In S1, the binder is polyvinyl alcohol, methylcellulose, or water-soluble paraffin.

3. The method for preparing a heater tray for producing liquid crystal glass substrates / cover plates according to claim 1, characterized in that, In S2, the shape of the mold is set according to the shape and shrinkage ratio of the alumina ceramic heating furnace plate, and it is made of alloy steel. The mold is required to be non-deformable and have a smooth, rust-free inner cavity.

4. The method for preparing a heater tray for producing liquid crystal glass substrates / cover plates according to claim 1, characterized in that, The shrinkage ratio of the obtained heating furnace plate is 1.05~1.

055.

5. The heater plate obtained by the method of any one of claims 1 to 4.

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