An isostatic pressing shaping method for MLCC green bodies, a composite functional film, and an MLCC element

Abstract

This invention relates to the field of multilayer ceramic capacitor manufacturing technology, and provides an isostatic pressing method for MLCC green blanks, a composite functional film, and MLCC elements. The method includes: providing an MLCC green blank and a composite functional film containing inorganic fillers; using the film to fully encapsulate the green blank and then performing isostatic pressing treatment; while densifying the green blank, the inorganic fillers apply constraint force to the edges and corners, causing the edges and corners to form rounded transition angles. This invention achieves simultaneous green blank densification and edge pre-forming, eliminating the subsequent rolling process, avoiding microcracks and internal electrode damage caused by mechanical grinding, improving product yield, electrical performance, and dimensional consistency, shortening the production cycle, and reducing manufacturing costs.

Description

Technical Field

[0001] This invention relates to the field of multilayer ceramic capacitor manufacturing technology, and in particular to an isostatic pressing method for MLCC green blanks, a composite functional film, and MLCC elements. Background Technology

[0002] Currently, in the standard manufacturing process of multilayer ceramic capacitors (MLCCs), the sintered ceramic chips typically have sharp edges and corners, and the end faces may be covered with a ceramic layer, making direct sealing impossible. Therefore, as... Figure 1 As shown, in traditional processes, chamfering is a crucial step after sintering, the purpose of which is to trim the edges and expose the inner electrode to facilitate the subsequent sealing process.

[0003] Patent document CN200810017673.2 discloses an ultra-high power multilayer composite film capacitor, which adopts a ceramic / polymer composite dielectric layer structure and introduces a low-temperature isostatic pressing process to densify the composite film during the manufacturing process. However, the isostatic pressing process in this solution only densifies the already formed composite film capacitor and does not involve the pre-forming treatment of the green blank's edges and corners. Furthermore, it does not use a composite film with a functional coating to cover the green blank. Therefore, the sintered capacitor still needs to rely on a subsequent mechanical trimming process to address the edge and corner issues.

[0004] In summary, existing technologies have failed to address the core issues in MLCC manufacturing, such as product damage, low yield, process redundancy, and high costs caused by reliance on post-grinding processes. There is an urgent need for a technical solution that can simultaneously pre-form the edges and corners of the green blank during isostatic pressing densification, thereby eliminating the dependence on the grinding process at its source. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose an isostatic pressing method for MLCC preforms, a composite functional film, and MLCC components, in order to solve the problems of easy product damage, low yield, redundant processes, and high costs caused by the reliance on post-rolling grinding processes in the MLCC manufacturing process of the prior art.

[0006] An isostatic pressing method for shaping a green MLCC preform includes: providing a green MLCC preform; providing a composite functional film, the composite functional film including a flexible substrate layer and a functional coating disposed on at least one side of the flexible substrate layer, the functional coating comprising a bonding resin and an inorganic filler dispersed in the bonding resin; fully encapsulating the green MLCC preform with the composite functional film to form an encapsulated body; and performing isostatic pressing on the encapsulated body to densify the green MLCC preform while applying a restraining force to the edges and corners of the green MLCC preform through the inorganic filler, so that the edges and corners of the green MLCC preform form rounded transition angles.

[0007] The above solution introduces a composite functional membrane containing inorganic fillers. During the isostatic pressing process, the rigid support provided by the inorganic fillers and the elastic deformation of the membrane layer are used to apply uniform constraints to the edges and corners of the green body, so that the edges and corners are pre-formed while the green body is densified. This eliminates the subsequent tumbling process and solves the damage problem caused by mechanical grinding.

[0008] In one embodiment, the flexible substrate layer is a heat-resistant polymer film, and the functional coating is located on the side of the flexible substrate layer facing the MLCC preform; the inorganic filler is configured to provide rigid support during the isostatic pressing process to assist in forming the rounded transition angle.

[0009] In one embodiment, the thickness of the flexible substrate layer is 8-60 μm, the thickness of the functional coating is 3-25 μm, the particle size of the inorganic filler is 10-200 nm, and the content of the inorganic filler in the functional coating is 3-25 wt%.

[0010] The above solution optimizes the film thickness and filler parameters to ensure that the functional coating provides shaping force while maintaining good peelability and surface quality.

[0011] As one implementation method, the method of fully encapsulating the MLCC preform using the composite functional film includes: placing the MLCC preform between the composite functional films and sealing the periphery using a vacuum heat-sealing method to form the encapsulation body with a sealed bag structure.

[0012] As one implementation method, the process parameters for such static pressure treatment include: temperature of 80-150℃, pressure of 30-150MPa, and holding time of 15-40min.

[0013] The above-mentioned process parameter range is a suitable window for achieving both densification and shape preservation, ensuring that the green body is dense inside and has regular edge and corner shapes.

[0014] In one implementation, the temperature is 100-120°C and the pressure is 50-100 MPa.

[0015] As one implementation, after the isostatic pressing process, the method further includes: peeling off the composite functional film to obtain a dense green body with no residue on the surface and rounded transition angles at the edges.

[0016] Furthermore, the present invention also provides a composite functional film for isostatic pressing of MLCC preforms, comprising: a flexible substrate layer; a functional coating disposed on at least one side of the flexible substrate layer, the functional coating comprising a bonding resin and an inorganic filler dispersed in the bonding resin; wherein, the composite functional film is configured to apply a restraining force to the edges and corners of the MLCC preform by means of the inorganic filler during isostatic pressing of the MLCC preform, thereby forming rounded transition angles at the edges and corners of the MLCC preform.

[0017] The aforementioned composite functional membrane is suitable for isostatic pressing forming process and can replace ordinary separator membranes, giving the green body a regular geometric shape.

[0018] In one embodiment, the thickness of the flexible substrate layer is 8-60 μm, the thickness of the functional coating is 3-25 μm, the particle size of the inorganic filler is 10-200 nm, and the content of the inorganic filler in the functional coating is 3-25 wt%.

[0019] In addition, the present invention also provides an MLCC element, which is prepared by the above method.

[0020] The beneficial effects of this invention are as follows: By introducing a composite functional film with a specific structure to fully encapsulate the green body before the isostatic pressing process, the invention utilizes the uniform constraint force provided by the inorganic fillers in the functional coating under isostatic pressing conditions to simultaneously pre-form the edges and corners of the green body during densification. This improvement eliminates the reliance on traditional tumbling and chamfering processes, avoiding problems such as microcracks in the ceramic matrix, damage to the internal electrodes, and end contamination caused by mechanical grinding. It also improves product yield, electrical performance (such as insulation resistance and loss factor), and batch-to-batch dimensional consistency. Simultaneously, eliminating the tumbling process shortens the production cycle, reduces material costs and environmental impact assessment pressure, achieving cost reduction and efficiency improvement, and is suitable for the large-scale production of all MLCC specifications. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart of the traditional MLCC manufacturing process.

[0023] Figure 2 This is a flowchart of the isostatic pressing method for shaping MLCC green blanks according to an embodiment of the present invention.

[0024] Figure 3 These are comparison images of the appearance of MLCC green blanks after isostatic pressing.

[0025] Figure 4 This is a schematic diagram of the shape of the MLCC product after sintering using the process of this invention.

[0026] Figure 5 This is a schematic diagram of the appearance of the MLCC product after electroplating using the process of this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0028] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] Example 1:

[0030] This embodiment provides an isostatic pressing method for shaping MLCC green blanks, such as... Figure 2 As shown, it includes the following steps:

[0031] Step S100: Provide MLCC green blank.

[0032] The MLCC green body is a green block formed by alternating stacking and cutting of barium titanate-based dielectric film and nickel-based internal electrode slurry.

[0033] Step S200: A composite functional membrane is provided, the composite functional membrane comprising a flexible substrate layer and a functional coating disposed on at least one side of the flexible substrate layer, the functional coating comprising an adhesive resin and an inorganic filler dispersed in the adhesive resin.

[0034] In this embodiment, a polyimide (PI) film is used as the support carrier for the flexible substrate layer. It possesses good heat resistance and ductility, and will not crack or undergo excessive plastic deformation under subsequent high temperature and high pressure conditions. The functional coating serves as the functional layer that directly contacts the green body. It should be understood that the inorganic filler is not limited to a specific material; any particulate material that can provide rigid support under isostatic pressure and does not adversely react with the green body is within the scope of protection of this invention, such as alumina, silica, and barium titanate ceramic powder. In this embodiment, alumina nanoparticles are used as the inorganic filler. The bonding resin serves to bond the filler to the substrate; in this embodiment, an acrylic resin is used, which possesses good film-forming and peeling properties.

[0035] Step S300: The composite functional film is used to fully encapsulate the MLCC preform to form an encapsulated body.

[0036] This full-coverage process aims to create a closed pressure-transmitting environment while establishing a tight contact between the functional coating and the green body surface. By placing the green body between the composite functional membranes and sealing it, the functional coating completely covers all surfaces of the green body, including corner areas. This tight fit eliminates air gaps between the membrane and the green body, ensuring uniformity of subsequent pressure transmission.

[0037] In step S400, the coating is subjected to isostatic pressing treatment. While densifying the MLCC green blank, the inorganic filler applies a constraint force to the edges and corners of the MLCC green blank, so that the edges and corners of the MLCC green blank form rounded transition angles.

[0038] During isostatic pressing, a fluid medium (such as high-temperature water) applies uniform pressure to the isotropic coating. The pressure is transmitted through the flexible substrate layer to the functional coating, and then acts on the surface of the green body. For the planar areas of the green body, the pressure acts directly on the densification of the green body; however, for the angular areas of the green body, the force mechanism is quite different.

[0039] Specifically, when pressure is applied to the coating, the inorganic filler particles within the functional coating form a microscopic rigid skeletal structure encapsulated by the binding resin. Due to the extremely small geometric radius of curvature at the green body's corners, the functional coating undergoes significant elastic deformation at these locations to conform to the green body's contour. At this point, the inorganic filler particles dispersed in the corner regions generate a micro-stress field of mutual compression under high pressure. This micro-stress field exerts a reverse constraint force or shaping force on the green body's corners.

[0040] This constraint force comprises a complex stress state with lateral components. It restricts the disordered flow of material at the green body's corners during densification, guiding it to deform towards a predetermined smooth shape. In other words, the inorganic filler acts as a mold at the microscopic level, achieving soft constraint on sharp corners within a flexible, macroscopic environment. By controlling the pressure and holding time, the sharp right angles at the green body's corners are gradually eroded and blunted, ultimately forming a smooth transition angle with a controllable radius of curvature (i.e., the R-angle in the industry). This smooth transition angle structure is retained during subsequent sintering shrinkage, thus achieving a geometry that meets end-sealing requirements without the need for mechanical grinding.

[0041] Through the above-described scheme, this embodiment utilizes the rigid support characteristics of the inorganic filler in the composite functional membrane to achieve precise shaping of the green body's edges and corners while simultaneously achieving isostatic densification. This not only avoids the mechanical damage and microcracks caused by traditional rolling processes but also significantly simplifies the manufacturing process and improves product consistency and reliability.

[0042] Example 2:

[0043] This embodiment further optimizes the specific structure and coating process of the composite functional membrane based on Embodiment 1.

[0044] Specifically, the flexible substrate layer is a heat-resistant polymer film, and the functional coating is located on the side of the flexible substrate layer facing the MLCC preform. The heat-resistant polymer film serves to withstand the high temperature and pressure environment during isostatic pressing, preventing the film from cracking or becoming excessively soft. In this embodiment, the substrate layer is made of polyimide (PI) film, which maintains good mechanical strength and dimensional stability within a temperature range of 80-150°C. The functional coating is located on the inner side, directly contacting the preform, and its purpose is to utilize the inorganic filler in the coating to form a microscopic shaping mold at the interface. It should be understood that the functional coating can also be located on both sides of the substrate layer, but in this embodiment, a single-sided location is sufficient to meet the shaping requirements and helps reduce material costs. The inorganic filler is configured to provide rigid support during the isostatic pressing process to assist in forming the rounded transition angle. This rigid support does not mean that the filler itself is incompressible, but rather that, relative to the soft bonding resin and the preform, the inorganic filler particles constitute a microscopic framework with a higher modulus. When pressure is applied to the corners, the frame can resist some deformation, thereby exerting a reverse constraint force on the corners of the green blank, forcing the sharp corners to deform into a rounded shape.

[0045] To ensure both shaping effect and subsequent peeling performance, this embodiment specifies the parameters of the film layer and filler. The thickness of the flexible substrate layer is 25 μm, and the thickness of the functional coating is 10 μm. Furthermore, the particle size of the inorganic filler is 80 nm, and its content in the functional coating is 12 wt%. When the filler particle size is at the nanoscale and the content is within the above range, the filler can be uniformly dispersed in the resin, forming a dense support network. Through the synergistic effect of the above parameters, the composite functional membrane of this embodiment can provide effective shaping force under high pressure and can be easily and completely peeled off after pressure relief, thus optimizing process performance.

[0046] In terms of the encapsulation process, the composite functional film is used to fully encapsulate the MLCC preform, including: placing the MLCC preform between the composite functional films and sealing the periphery using a vacuum heat-sealing method to form a sealed bag structure. Specifically, the MLCC preform is first placed between two layers of composite functional films, with the functional coating facing the preform. Then, a vacuum packaging machine is used to remove the air between the film and the preform, and the periphery of the film is immediately heat-sealed. In this embodiment, the heat-sealing temperature is set to 120℃ and the heat-sealing pressure is 0.3MPa to ensure a firm and leak-free seal. If air remains inside the encapsulation, during isostatic pressing, the air bubbles will be extremely compressed and generate localized high-pressure concentration, easily leading to indentations or cracks on the surface of the preform. The sealed bag structure formed by vacuum heat sealing eliminates air gaps, allowing the pressure medium (water) to act evenly and without dead angles on all surfaces of the preform through the flexible film material, thus ensuring the quality of the rounded transition angles.

[0047] Example 3:

[0048] This embodiment optimizes the process parameters of isostatic pressing based on Embodiment 1 or Embodiment 2, and describes the post-processing steps in detail.

[0049] Specifically, the process parameters for such static pressure treatment include: temperature of 80-150℃, pressure of 30-150MPa, and holding time of 15-40min.

[0050] As part of the experimental group, the temperature was 110℃ and the pressure was 80MPa. Under these conditions, the bonding resin in the composite functional membrane was in a suitable viscoelastic state, which allowed it to adhere tightly to the surface of the green body under high pressure while ensuring easy demolding after pressure relief. Simultaneously, the inorganic filler could form a stable micro-stress field in the medium pressure range, applying a moderate constraint force to the edges and corners of the green body. Experimental results showed that the edges and corners of the green body formed smooth transition angles with uniform radii of curvature, and the internal density of the green body was high, with no delamination.

[0051] As a comparative example 1, the pressure was reduced to 20 MPa. The results showed that due to insufficient pressure, the inorganic filler in the functional coating could not form an effective rigid support skeleton, and the constraint force on the green body's edges was weak. Although the green body underwent a certain degree of densification, the edges remained sharp and failed to form a clear rounded transition angle, thus failing to meet the requirements for subsequent direct end-sealing.

[0052] As a comparative example 2, the temperature was increased to 160℃. The results showed that excessively high temperatures caused the flexible substrate layer (such as PET film) in the composite functional film to soften excessively or even shrink, and the adhesive resin in the functional coating to become viscous. During the pressure holding process, the film material and the surface of the green body became thermally adhered, making subsequent peeling difficult and leaving film residue on the surface of the green body, which seriously affected the surface quality and yield of the product.

[0053] Therefore, the process parameter range defined in this invention is a suitable selection after balancing the shaping effect, membrane stability and peel performance, and has good technical advantages.

[0054] Following the isostatic pressing treatment, the method further includes: peeling off the composite functional membrane. Specifically, the shape of the green body after hydraulic pressing is as follows: Figure 3 As shown, the coating is removed from the isostatic pressing equipment, cut along the sealing edge, and the composite functional film is peeled off from the surface of the MLCC green body, resulting in a green body block with regular edges and uniform density. The block is cut into individual green bodies, degreased to remove organic binders, and then sintered at high temperature in a reducing atmosphere to form a dense ceramic chip, such as... Figure 4 As shown, since the corner pre-forming has been completed above, the corners of the sintered ceramic chip naturally maintain a rounded shape, and the end electrode is not excessively covered by the ceramic layer, so no additional polishing is required to meet the end-capping requirements.

[0055] After sintering, the ceramic chips go directly to the end-capping process without undergoing the traditional tumbling process. The aim is to completely eliminate electrode damage, microcracks, and dimensional deviations caused by tumbling, while saving equipment, energy, and labor costs.

[0056] After sintering, the two ends of the MLCC (Multi-Layer Ceramic Capacitor) are immersed in a special metal paste (typically made of copper (Cu) or silver (Ag) powder mixed with an organic carrier and binder). After immersion, a layer of wet, paste-like metal adheres evenly to both ends of the product; this forms the initial end electrodes. The coated products are then sent to a high-temperature furnace for processing (approximately 710-900℃ for copper electrodes), followed by electroplating with nickel and tin layers for end protection. The purpose is to achieve conductivity between the end electrodes and the internal electrodes, forming a solderable end structure. The electroplated product... Figure 5 As shown.

[0057] It should be understood that the specific parameter values ​​mentioned above are for illustrative purposes only. Those skilled in the art can make reasonable adjustments within a temperature range of 80-150℃ and a pressure range of 30-150MPa, based on the specific dimensions of the green body and the material properties of the film, in order to obtain the best shaping effect.

[0058] Example 4:

[0059] This embodiment provides a composite functional film for isostatic pressing of MLCC preforms, comprising: a flexible substrate layer; and a functional coating disposed on at least one side of the flexible substrate layer, the functional coating comprising an adhesive resin and an inorganic filler dispersed in the adhesive resin; wherein, the composite functional film is configured to apply a restraining force to the edges and corners of the MLCC preform by means of the inorganic filler during isostatic pressing of the MLCC preform, thereby forming rounded transition angles at the edges and corners of the MLCC preform.

[0060] From a structural perspective, this is a dual-layer composite structure combining support and function. The flexible substrate layer forms the mechanical skeleton of the membrane, its function being to withstand the high tension and tearing forces during isostatic pressing, ensuring that the membrane does not rupture under severe deformation. The functional coating constitutes the working surface of the membrane, directly contacting the MLCC preform. This material composition utilizes the flexibility of the bonding resin to achieve adhesion to the preform surface, while simultaneously leveraging the high modulus properties of the inorganic fillers to construct a microscopic mechanical transmission network.

[0061] In this embodiment, the composite functional membrane acts as a flexible mold. When fluid pressure is transmitted through the substrate layer to the functional coating, the inorganic filler particles dispersed within the coating generate mutual compressive forces. Due to the extreme geometric curvature at the green body's edges, this interparticle compressive force is converted into a lateral constraint force on the green body's edges, thereby forcing the sharp edges to deform towards a rounded shape. It should be understood that this shaping capability is inherent to the product's own structure; it can spontaneously produce a shaping effect when applied to a high-pressure environment.

[0062] To ensure good process adaptability of the composite functional membrane, this embodiment further limits its structural parameters. The thickness of the flexible substrate layer is 25 μm, and the thickness of the functional coating is 10 μm. This thickness range balances the contradiction between flexibility and shaping force. If the substrate layer is too thin, the membrane strength is insufficient and it is prone to perforation under high pressure; if it is too thick, the membrane is rigid and it is difficult to tightly wrap the tiny edges of the green body. The thickness of the functional coating directly determines the depth of the shaping force. A 10 μm coating can ensure a sufficient number of filler particles to form a constraining skeleton, while avoiding peeling difficulties or cost waste caused by an excessively thick coating.

[0063] Furthermore, the inorganic filler has a particle size of 80 nm and its content in the functional coating is 12 wt%. The nanoscale particle size ensures uniform dispersion of the filler in the resin, avoiding indentations on the green surface due to excessively large particles. The 12 wt% content controls the cohesiveness of the coating, enabling it to provide support under high pressure and easily peel off from the green surface after depressurization, without causing coating cracking or powdering, thus ensuring the cleanliness of the green surface.

[0064] Through the above structural design, the composite functional membrane of this embodiment is not only a physical protective material, but also a special consumable with active shaping function. It can replace the ordinary film that provides passive protection in traditional processes, directly giving the green body a regular geometric shape, and providing a material basis for eliminating the subsequent tumbling process.

[0065] Example 5:

[0066] This embodiment provides an MLCC element prepared by the method proposed in this application. To verify the practical application effect of the isostatic pressing method and composite functional film provided by this invention, this embodiment conducts a detailed performance comparison test between the MLCC element prepared by the process of this invention and the MLCC element prepared by the traditional rolling process.

[0067] Specifically, the experimental setup was as follows: the experimental group used MLCC elements of specification 1206 manufactured using the process parameters (temperature 110℃, pressure 80MPa) of Example 3 of this invention; the control group used MLCC elements of the same specification manufactured using the traditional standard process (sintering followed by grinding and chamfering). Each group had 1000 samples. The tests covered electrical performance, appearance and structural yield, and process efficiency.

[0068] The test results are shown in Table 1-3 below.

[0069] Table 1. Comparison of electrical properties (at room temperature)

[0070]

[0071] As shown in Table 1, the MLCC components fabricated using the process of this invention outperform those produced by the traditional rolling process in all electrical performance indicators. The rated capacitance deviation has narrowed from ±7% to ±5%, indicating that the pre-formed process of this invention results in better consistency of the green blank during sintering shrinkage, thereby improving the accuracy of the capacitance. The improvement in insulation resistance (IR) and loss factor (DF) is particularly significant: insulation resistance is no less than 8 × 10⁻⁶. 9 Ω increased to no less than 1.0 × 10¹ 0The Ω value is increased by approximately 25%; the loss factor DF is reduced from 0.045 to below 0.038, a decrease of approximately 15%. This effect is attributed to the fact that the present invention eliminates the mechanical tumbling process, avoiding the risk of micro-damage or wire breakage of the internal electrode caused by physical impact during tumbling, thereby ensuring the integrity and conductivity continuity of the internal electrode and thus optimizing the electrical performance.

[0072] Table 2 Comparison of Appearance and Structural Yield

[0073]

[0074] As shown in Table 2, in terms of appearance and structural yield, the overall process yield of this invention increased from 89.5% to 94.2%, an improvement of approximately 5 percentage points. Specific analysis of defects revealed that the defect rate of micro-cracks at the edges and corners caused by tumbling in traditional processes was as high as 4.2%, while that of this invention was only 0.5%, essentially eliminating such secondary crack defects. Furthermore, the uneven copper exposure defect of the end-face electrodes, common in traditional processes (4.8%), was reduced to 0.7% in this invention. This invention, through the constraint of the composite functional film, ensures that the green blank forms a regular, rounded transition angle before sintering, resulting in uniform exposure of the end-face electrodes and avoiding copper exposure defects caused by inconsistent tumbling cutting amounts. The internal electrode connectivity yield increased from 93.1% to 97.6%, further confirming the effective protection of the internal electrodes by the non-tumbling process.

[0075] Table 3. Cost and Efficiency Comparison

[0076]

[0077] As shown in Table 3, in terms of production efficiency and cost, by eliminating the grinding process and its associated cleaning and wastewater treatment steps, the production cycle per batch of the process of this invention is shortened by 28% compared to the traditional process, and the cost of consumables such as grinding balls and polishing fluid is reduced by more than 35%. In summary, the MLCC components produced using the method of this invention exhibit superior insulation characteristics and lower losses in electrical performance, and improvements have also been achieved in yield, consistency, and production cost, demonstrating good market application value.

[0078] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0079] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for isostatic pressing and shaping of MLCC green blanks, characterized in that, include: Provide MLCC green blanks; A composite functional membrane is provided, the composite functional membrane comprising a flexible substrate layer and a functional coating disposed on at least one side of the flexible substrate layer, the functional coating comprising an adhesive resin and an inorganic filler dispersed in the adhesive resin; The composite functional film is used to fully encapsulate the MLCC preform to form an encapsulated body; The coating is subjected to isostatic pressing treatment, which densifies the MLCC green blank while applying a constraint force to the edges and corners of the MLCC green blank through the inorganic filler, so that the edges and corners of the MLCC green blank form rounded transition angles.

2. The method according to claim 1, characterized in that, The flexible substrate layer is a heat-resistant polymer film, and the functional coating is located on the side of the flexible substrate layer facing the MLCC preform; The inorganic filler is configured to provide rigid support during the isostatic pressing process to help form the rounded transition angle.

3. The method according to claim 2, characterized in that, The thickness of the flexible substrate layer is 8-60 μm, and the thickness of the functional coating is 3-25 μm; The inorganic filler has a particle size of 10-200 nm and its content in the functional coating is 3-25 wt%.

4. The method according to claim 1, characterized in that, The process of fully encapsulating the MLCC preform using the composite functional film includes: The MLCC preform is placed between the composite functional films, and the periphery is sealed by vacuum heat sealing to form the encapsulation body with a sealed bag structure.

5. The method according to claim 1, characterized in that, The process parameters for the isostatic pressing treatment include: temperature of 80-150℃, pressure of 30-150MPa, and holding time of 15-40min.

6. The method according to claim 5, characterized in that, The temperature is 100-120℃, and the pressure is 50-100MPa.

7. The method according to claim 1, characterized in that, After the isostatic pressing treatment, the method further includes: Peel off the composite functional film to obtain a dense green body with no residue on the surface and rounded transition angles at the edges.

8. A composite functional film for isostatic pressing of MLCC green blanks, characterized in that, include: Flexible substrate layer; A functional coating is disposed on at least one side of the flexible substrate layer, the functional coating comprising an adhesive resin and an inorganic filler dispersed in the adhesive resin; The composite functional membrane is configured such that, during isostatic pressing of the MLCC preform, the inorganic filler applies a constraint force to the edges and corners of the MLCC preform, thereby forming rounded transition angles at the edges and corners of the MLCC preform.

9. The composite functional membrane according to claim 8, characterized in that, The thickness of the flexible substrate layer is 8-60 μm, and the thickness of the functional coating is 3-25 μm; The inorganic filler has a particle size of 10-200 nm and its content in the functional coating is 3-25 wt%.

10. An MLCC element, characterized in that, The MLCC element is prepared by the method according to any one of claims 1 to 7.

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