Method for improving lamination bonding property of water-based ceramic plain sheets

Abstract

The invention provides a method for improving the lamination binding property of water-based ceramic plain sheets, and relates to the technical field of ceramic materials. The method comprises the following steps: firstly, coating an interface binder on a non-smooth surface / smooth surface of the ceramic wafer and drying; and then laminating at least two ceramic wafers treated by the interface binder, and carrying out thermocompression bonding to obtain the laminated ceramic wafer. According to the method disclosed by the invention, the interlayer bonding strength is remarkably enhanced, the problems of sintering layering and warping of the laminated ceramic plain sheet caused by insufficient bonding force are effectively relieved, the technical bottleneck of poor wettability of the water-based tape casting slurry and the existing film belt is further overcome, and the plain sheet with smooth surface and uniform thickness can be stably prepared.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a method for improving the bonding properties of water-based ceramic sheet laminations. Background Technology

[0002] In the current field of ceramic sheet preparation, a smooth film strip is typically loaded onto the ceramic green sheet to form a smooth ceramic sheet, thereby improving the bonding strength of multilayer green sheets. However, in the process of water-based tape casting, the hydrophobic nature of the water-based tape makes it difficult for the casting slurry to form a uniform and smooth casting surface on the film strip. Therefore, this leads to a mismatch between the water-based tape and the existing film strip during the stacking and composite preparation of ceramic sheets. Furthermore, insufficient interlayer bonding strength during multilayer pressing results in delamination and warping during subsequent sintering.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a method for improving the bonding strength of water-based ceramic sheet stacks, which effectively alleviates the problems of delamination and warping of stacked ceramic sheets due to insufficient bonding strength during sintering.

[0005] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: This invention provides a method for improving the bonding strength of water-based ceramic sheet laminations, comprising the following steps: (A) Preparation of ceramic blanks with smooth and non-smooth surfaces; (B) Apply an interface adhesive to the non-glossy / glossy surface of the ceramic sheet and allow it to dry; (C) Stack at least two ceramic sheets treated in step (B) with one side facing the other in a non-glossy / glossy manner; (D) The stacked sheets are hot-pressed to obtain laminated ceramic sheets.

[0006] Furthermore, the surface roughness Ra1 of the smooth surface and the surface roughness Ra2 of the non-smooth surface satisfy the following relationship: Ra1≤0.6×Ra2.

[0007] Furthermore, the ceramic sheet is prepared by coating a water-based casting slurry onto a film strip and then drying it through multiple temperature-controlled stages.

[0008] Furthermore, by weight percentage, the aqueous casting slurry comprises: The composition includes 55%~70% ceramic powder, 0.1%~1.0% dispersant, 10%~20% aqueous solvent, 10%~15% binder, 0.1%~0.5% thickener, and 0.08%~0.3% surfactant.

[0009] Furthermore, the surfactant is one or more of polyoxyethylene octylphenyl ether or polyethylene glycol fatty acid ester.

[0010] Furthermore, the aqueous casting slurry is prepared using a multi-stage stirring method; Preferably, the multi-stage stirring includes: The first stage uses high-speed stirring, with a stirring speed of 800~1000 rpm; The second stage uses medium-speed stirring, with a stirring rate of 450~600 rpm; The third stage uses low-speed stirring, with a stirring rate of 200~400 rpm.

[0011] Furthermore, the film tape is a highly lubricating film tape with a silicon surface treatment.

[0012] Furthermore, the interfacial adhesive in step (B) is an oil-based adhesive; Preferably, the oily adhesive is an oily adhesive containing 4%~10% polyvinyl butyral (PVB) powder and 3%~5% plasticizer, with solvent oil as the dispersion medium.

[0013] Furthermore, in step (B), the drying temperature is 30~50℃ and the time is 30~60min.

[0014] Furthermore, the plate pressing temperature in step (C) is 45~65℃, and the plate pressing parameters are 800~1000℃.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This application provides a method for improving the bonding strength of water-based ceramic sheet laminates. The method first coats the non-glossy / glossy surface of the ceramic sheet with an interfacial binder and dries it. Then, at least two ceramic sheets treated with the interfacial binder are laminated with their glossy and non-glossy / glossy surfaces facing each other and hot-pressed to obtain laminated ceramic sheets. This method significantly enhances the interlayer bonding strength, effectively alleviates the problems of delamination and warping during sintering of laminated ceramic sheets caused by insufficient bonding force, and overcomes the technical bottleneck of poor wettability between water-based casting slurries and existing film tapes. It can stably produce ceramic sheets with smooth surfaces and uniform thickness. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the stacking of ceramic green sheets provided in Experimental Example 1 of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] According to one aspect of the present invention, a method for improving the bonding strength of water-based ceramic sheet laminates includes the following steps: (A) Preparation of ceramic blanks with smooth and non-smooth surfaces; (B) Apply an interface adhesive to the non-glossy / glossy surface of the ceramic sheet and allow it to dry; (C) Stack at least two ceramic sheets treated in step (B) with one side facing the other in a non-glossy / glossy manner; (D) The stacked sheets are hot-pressed to obtain laminated ceramic sheets.

[0020] This application provides a method for improving the bonding strength of water-based ceramic sheet laminates. The method first coats the non-glossy / glossy surface of the ceramic sheet with an interfacial binder and dries it. Then, at least two ceramic sheets treated with the interfacial binder are laminated with their glossy and non-glossy / glossy surfaces facing each other and hot-pressed to obtain laminated ceramic sheets. This method significantly enhances the interlayer bonding strength, effectively alleviates the problems of delamination and warping during sintering of laminated ceramic sheets caused by insufficient bonding force, and overcomes the technical bottleneck of poor wettability between water-based casting slurries and existing film tapes. It can stably produce ceramic sheets with smooth surfaces and uniform thickness.

[0021] In a preferred embodiment of the present invention, the surface roughness Ra1 of the smooth surface and the surface roughness Ra2 of the non-smooth surface satisfy the following relationship: Ra1≤0.6×Ra2.

[0022] In a preferred embodiment of the present invention, the ceramic sheet is prepared by coating an aqueous casting slurry onto a film strip and then drying it.

[0023] In a preferred embodiment of the present invention, the aqueous casting slurry comprises, by weight percentage: The composition includes 55%~70% ceramic powder, 0.1%~1.0% dispersant, 10%~20% aqueous solvent, 10%~15% binder, 0.1%~0.5% thickener, and 0.08%~0.3% surfactant.

[0024] As an optional implementation, the ceramic powder is 55%~70%, for example, it can be 55%, 60%, 65%, 70%, or any value between 55% and 70%; As an optional implementation, the dispersant is 0.1% to 1.0%, for example, it can be 0.1%, 0.5%, 1.0%, or any value between 0.1% and 1.0%; As an optional implementation, the aqueous solvent is 10% to 20%, for example, it can be 10%, 15%, 20%, or any value between 10% and 20%; As an optional implementation, the adhesive is 10% to 15%, for example, it can be 10%, 12%, 15%, or any value between 10% and 15%; As an optional implementation, the thickener is 0.1% to 0.5%, for example, it can be 0.1%, 0.3%, 0.5%, or any value between 0.1% and 0.5%; As an optional implementation, the surfactant is 0.08% to 0.3%, for example, it can be 0.08%, 0.2%, 0.3%, or any value between 0.08% and 0.3%.

[0025] In the preferred embodiments described above, the surfactant is one or more of polyoxyethylene octylphenyl ether or polyethylene glycol fatty acid ester.

[0026] As a preferred embodiment, the surfactant contained in the slurry of this application can effectively reduce the surface tension of the slurry and improve the wettability and compatibility between the slurry and the silicone film tape.

[0027] In a preferred embodiment of the present invention, the aqueous casting slurry is prepared by multi-stage stirring. As an optional implementation, the rate control of the multi-stage stirring is as follows: The first stage uses high-speed stirring, with a stirring speed of 800~1000 rpm, for example, it can be 800 rpm, 900 rpm, 1000 rpm, or any value between 800~1000 rpm; The second stage uses medium-speed stirring, with a stirring rate of 450~600 rpm, for example, it can be 450 rpm, 500 rpm, 600 rpm, or any value between 450~600 rpm; The third stage uses low-speed stirring, with a stirring rate of 200~400 rpm, for example, it can be 200 rpm, 300 rpm, 400 rpm, or any value between 200 and 400 rpm.

[0028] In a preferred embodiment of the present invention, the film strip is a highly lubricating film strip with a silicon surface treatment.

[0029] Preferably, the film tape is a highly lubricating film tape with a silicone surface treatment. For example, the film tape can be obtained by coating a polyester substrate with silicone oil to form a release layer, and the release force of the film tape is 10~30 g / inch, and the thickness is 100~200 μm.

[0030] In a preferred embodiment of the present invention, the interfacial adhesive in step (B) is an oil-based adhesive; As an optional embodiment, the oily adhesive uses solvent oil as the dispersion medium, wherein the mass fraction of each component is: 4% to 10% polyvinyl butyral (PVB) powder, for example, it can be 4%, 6%, 8%, 10%, or any value between 4% and 10%; 3% to 5% plasticizer, for example, it can be 3%, 4%, 5%, or any value between 3% and 5%.

[0031] In a preferred embodiment of the present invention, the drying temperature in step (B) is 30~50°C and the time is 30~60 min.

[0032] As an optional implementation, the drying temperature is 30~50℃, for example, it can be 30℃, 35℃, 40℃, 45℃, 50℃, or any value between 30~50℃; As an optional implementation, the drying time is 30 to 60 minutes, for example, it can be 30 minutes, 40 minutes, 50 minutes, or 60 minutes, or any value between 30 and 60 minutes.

[0033] In a preferred embodiment of the present invention, the plate pressing temperature in step (C) is 45~65°C and the plate pressing parameters are 7.8~10kN.

[0034] The technical solution of the present invention will be further described below with reference to the embodiments.

[0035] Example 1 A ceramic green sheet, comprising a ceramic substrate, wherein both surfaces of the ceramic substrate are loaded with a film strip, wherein: The film tape is obtained by coating the surface of a polyester substrate with silicone oil to form a release layer. The release force of the film tape is 20 g / inch and the thickness is 150 μm.

[0036] A cast film layer (glossy surface) is applied to one surface of the ceramic sheet, while the side without the cast film layer is a non-glossy surface. The method for preparing the ceramic green sheet includes the following steps: (1) Weigh the raw materials for slurry preparation according to the following mass percentages, see Table 1 for details.

[0037] Table 1:

[0038] (2) Mix all the dispersant in the total amount of the formula with two-thirds of the aqueous solvent in a stirring container and stir at 300~500 rpm for 5~10 minutes until the dispersant is completely dissolved and a uniform premix is ​​formed. (3) Under continuous stirring, slowly and in batches add all the alumina powder to the premixed liquid. After all the powder has been added, increase the stirring speed to 800-1000 rpm and continue stirring for 30-60 minutes to obtain a pre-dispersed slurry; (4) Transfer the initially dispersed slurry to a ball mill jar, add alumina grinding balls (ball-to-material ratio of 2:1 to 3:1), and ball mill at a speed of 200-300 rpm for 4 to 8 hours.

[0039] (5) Slowly add the thickener to the remaining one-third of the aqueous solvent and stir at low speed to allow it to swell fully and form a uniform gel.

[0040] (6) Mix the above gel liquid with all the adhesives and stir at 200-400 rpm for 15-30 minutes to form a uniform organic mixture solution.

[0041] (7) Place the primary slurry after ball milling in step (4) back into the mixer. Under medium speed stirring at 400~600 rpm, slowly add the organic mixed solution prepared in step b to the primary slurry. After all the solution has been added, continue stirring at 600~800 rpm for 60~120 minutes to ensure that the components of the slurry are highly homogeneous.

[0042] (8) Transfer the uniformly mixed slurry from step (7) to a vacuum degassing device and treat it under a vacuum of -0.095 MPa to -0.1 MPa for 10 to 30 minutes until no bubbles escape from the surface of the slurry. Then, let the slurry stand and age for 12 to 24 hours to completely release the internal stress and stabilize the rheological properties of the slurry to obtain the cast slurry.

[0043] (9) Casting molding: Pour the casting slurry onto the surface of the film belt and use a special scraper tool to scrape the slurry so that it is evenly coated on the surface of the film belt. At the same time, a segmented temperature-controlled drying process is adopted: first temperature zone: 30~40℃; second temperature zone: 40~45℃; third temperature zone: 45~50℃; low temperature: 30~40℃.

[0044] Finally, a flat green sheet with different smoothness on the upper and lower surfaces is obtained, wherein: the side with the cast film layer is a smooth surface, and the side without the cast film layer is a non-smooth surface; the roughness of the smooth and non-smooth surfaces in each embodiment is shown in Table 2.

[0045] Table 2:

[0046] Experimental Example 1 The ceramic green sheets prepared in Example 1 were stacked to form multilayer ceramic components and then sintered.

[0047] Figure 1 This is a schematic diagram of the stacking of ceramic green sheets provided for this experimental example.

[0048] See Figure 1 It can be seen that when multiple ceramic green sheets are stacked, the lower contact surface of the ceramic green sheet is called the first contact surface, and the upper contact surface of the ceramic green sheet is called the second contact surface.

[0049] The specific method is as follows: (1) Provide ceramic green sheets for preparing multilayer ceramic components, coat the second contact surface of the ceramic green sheets with an interface adhesive, and then stack the multilayer ceramic green sheets. After aligning and overlapping the first contact surface with the second contact surface coated with the interface adhesive, press them together to form a multilayer ceramic structure; The interface adhesive has a molecular weight of 8,000 to 12,000. The interface adhesive is an oil-based adhesive system containing 4 to 10% polyvinyl butyral (PVB) powder and 3 to 5% plasticizer, with solvent oil as the dispersion medium.

[0050] Table 3:

[0051] (2) The interface adhesive of experimental group 1 was applied. The specific structure is shown in Table 4.

[0052] Table 4:

[0053] Note: The pressing pressure is 7.8 kN, and the holding pressure is 8 s.

[0054] As shown in Table 4, in the combination of glossy and non-glossy surfaces, only the solution of applying an interfacial adhesive to the specific interface combination of glossy and non-glossy surfaces in Embodiment 3 can achieve stable and effective interlayer bonding. This indicates that the enhanced interlayer bonding strength of the laminated ceramic sheets of the present invention is not due to simple material coating, but rather stems from the synergistic effect between the "glossy / non-glossy" structure and the interfacial adhesive. That is, the microscopic roughness of the non-glossy surface provides strong mechanical anchoring points, while the glossy surface ensures dense contact at the interface. Together with the interfacial adhesive, the two form an interlayer bonding force that surpasses traditional methods.

[0055] Meanwhile, as shown in Table 4, effective bonding could not be achieved in either the "non-glossy" coating (Example 2) or the "non-glossy / non-glossy" lamination (Example 4). This demonstrates that the technical inference that "rough surface coating is effective" cannot achieve gasket bonding, and clearly proves that the specific pairing relationship of the lamination interface in this application is the decisive factor in achieving bonding.

[0056] (3) Debinding and sintering: The multilayer ceramic structure is subjected to low-temperature debinding treatment at a temperature of 480℃ and a holding time of 7 hours to fully remove the binder and obtain the laminated ceramic sheet.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the lamination strength of water-based ceramic green sheet, characterized by, The method comprises the following steps: (A) preparing a ceramic substrate with a glossy surface and a non-glossy surface; (B) applying an interface adhesive on the non-glossy surface / glossy surface of the ceramic substrate and drying; (C) stacking at least two ceramic substrates treated in step (B) with their respective surfaces in a non-glossy surface / glossy surface opposing manner; (D) hot-pressing the stacked substrates to obtain a laminated ceramic substrate.

2. The method of claim 1, wherein, The surface roughness Ra1 of the glossy surface and the surface roughness Ra2 of the non-glossy surface satisfy the relationship: Ra1≤ 0.6×Ra2.

3. The method of claim 1, wherein, The ceramic substrate is prepared by coating a water-based casting slurry on a film belt and drying.

4. The method of claim 3, wherein, The water-based casting slurry comprises, by weight percentage: ceramic powder 55%~70%, dispersant 0.1%~1.0%, water-based solvent 10%~20%, binder 10%~15%, thickening agent 0.1%~0.5%, and surfactant 0.08%~0.3%.

5. The method of claim 4, wherein, The surfactant is one or more of polyoxyethylene octylphenyl ether or polyethylene glycol fatty acid ester.

6. The method of claim 4, wherein, The water-based casting slurry is prepared by multi-stage stirring; Preferably, the multi-stage stirring comprises: the first stage uses high-speed stirring with a stirring rate of 800~1000 rpm; the second stage uses medium-speed stirring with a stirring rate of 450~600 rpm; the third stage uses low-speed stirring with a stirring rate of 200~400 rpm.

7. The method of claim 3, wherein, The film belt is a high-lubricity film belt with a silicon surface treatment on the surface.

8. The method of claim 1, wherein, The interface adhesive in step (B) is an oily adhesive; Preferably, the oily adhesive is an oily adhesive with solvent oil as the dispersion medium, containing 4%~10% polyvinyl butyral glue powder and 3%~5% plasticizer by mass fraction.

9. The method of claim 1, wherein, The drying temperature in step (B) is 30~50℃, and the drying time is 30~60 min.

10. The method of claim 1, wherein, The plate pressing temperature of the hot-pressing in step (C) is 45~65℃, and the plate pressing parameter is 7.8~10 kN.

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