Temperature self-adaptive thin film capacitor material and manufacturing method thereof
By employing molecular-level dispersion and interface modification of polyetherimide substrate film and barium titanate potassium niobate composite ceramic particles in film capacitors, the problems of dielectric constant fluctuation and ceramic particle agglomeration in traditional film capacitor materials under temperature changes are solved, achieving wide-temperature-range dielectric stability and high-efficiency capacitance performance.
Patent Information
- Application Number
- CN202511528999.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-23
- Publication Date
- 2026-01-23
AI Technical Summary
Traditional film capacitor materials exhibit significant fluctuations in dielectric constant with temperature changes, and the ceramic particles are poorly dispersed, easily agglomerating, which affects dielectric performance and capacitance efficiency.
A polyetherimide substrate film and barium titanate potassium niobate composite ceramic particles were used. Through the combination of dispersants and antioxidants, the ceramic particles were dispersed at the molecular level inside the substrate film. The positive temperature coefficient effect of barium titanate and the low-temperature dielectric properties of potassium niobate were utilized to achieve synergistic effects. The interfacial compatibility was optimized by combining an organic coupling agent modification layer.
Maintaining a stable dielectric constant over a wide temperature range reduces dielectric loss, improves the long-term stability and capacitance efficiency of the material, and enhances its mechanical properties.
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Figure CN121379149A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of thin film capacitor materials, in particular to a temperature adaptive thin film capacitor material and a manufacturing method. BACKGROUND
[0002] Thin film capacitor materials are mainly used in electronic devices that have high requirements for capacitor dielectric properties, temperature adaptability and long-term stability, such as power control systems of new energy vehicles, industrial frequency conversion devices, aerospace electronic instruments and other scenes, aiming to provide core capacitor materials that can maintain stable working performance in different temperature environments for such devices.
[0003] In the prior art, traditional thin film capacitor materials often cannot balance mechanical support and dielectric stability in a wide temperature range. Although some materials can provide certain insulation and mechanical strength, the dielectric constant fluctuates greatly when the temperature changes, which cannot meet the use requirements in a wide temperature environment. At the same time, the dispersion effect of ceramic particles in the base material is poor, and agglomeration is easy to occur, which not only affects the uniformity of dielectric properties, but also increases dielectric loss and reduces capacitor efficiency. SUMMARY
[0004] In view of the deficiencies of the prior art, the present application provides a temperature adaptive thin film capacitor material and a manufacturing method to solve the technical problems that the dispersion effect of ceramic particles in the base material is poor, agglomeration is easy to occur, which not only affects the uniformity of dielectric properties, but also increases dielectric loss and reduces capacitor efficiency.
[0005] To achieve the above-mentioned purposes, the present application provides the following technical solution: a temperature adaptive thin film capacitor material, comprising: a polyetherimide base film as a substrate support and barium titanate potassium niobate composite ceramic particles, the barium titanate potassium niobate composite ceramic particles are uniformly distributed in the interior of the polyetherimide base film in a discrete manner, the interior of the polyetherimide base film contains a dispersing agent and an antioxidant, the dispersing agent is distributed in the interface region of the PEI molecular chain of the polyetherimide base film and the barium titanate potassium niobate composite ceramic particles to form molecular-level dispersion, and the antioxidant molecules uniformly embed between the PEI molecular chains of the polyetherimide base film and cannot chemically bond with PEI and the composite ceramic particles.
[0006] The polyetherimide base film provides stable mechanical support and insulation performance, the barium titanate potassium niobate composite ceramic particles are uniformly dispersed in the interior, and the positive temperature coefficient (PTC) effect of barium titanate and the low-temperature dielectric properties of potassium niobate synergistically act to make the material maintain stable dielectric constant in a wide temperature range; the dispersing agent improves the interfacial compatibility of the ceramic particles and the polymer matrix, avoids agglomeration and reduces dielectric loss; and the antioxidant inhibits the oxidative degradation of the PEI molecular chain during preparation and use, thereby ensuring the long-term stability of the material.
[0007] Preferably, the polyetherimide base film is a uniform film layer structure without air bubbles and pinholes, the internal PEI molecular chain is partially oriented, the surface roughness is low and flat, the barium titanate potassium niobate composite ceramic particles are spherical, the particle size distribution is narrow, the internal part is composed of barium titanate phase and potassium niobate phase, and a clear phase interface is formed between the two phases, and an organic coupling agent modified layer is arranged on the surface of the particles.
[0008] The structure without air bubbles and pinholes ensures the high insulation and uniform electric field distribution of the film; the partially oriented PEI molecular chain improves the mechanical strength and dimensional stability of the film; the spherical and narrow particle size distribution of the composite ceramic particles is beneficial to uniform dispersion and reduces local electric field concentration; the clear phase interface and the surface coupling agent modified layer further optimize the ceramic / polymer interface bonding, reduce the interface polarization loss, and thus improve the overall performance of the capacitor.
[0009] Preferably, the organic coupling agent modified layer is a monolayer formed by silane coupling agent and titanate coupling agent, and the interface region is formed by mutual penetration of PEI molecular chain and coupling agent modified layer.
[0010] The coupling agent monolayer is combined with the surface of the ceramic particles by chemical bond, and the other end interacts with the PEI molecular chain, forming a strong bonding force and good compatibility in the interface region, reducing interface defects and charge accumulation, thereby reducing dielectric loss and improving the breakdown resistance of the material.
[0011] Preferably, the dispersing agent is glycerol tristearate, and the antioxidant is pentaerythritol tetra(ethylhexanoate).
[0012] Glycerol tristearate can effectively reduce the van der Waals force between ceramic particles, prevent agglomeration, and make the particles uniformly distributed in the PEI matrix; pentaerythritol tetra(ethylhexanoate) as a high-efficiency antioxidant can capture free radicals and decompose hydroperoxide, delay the oxidative degradation of PEI molecular chain, and ensure that the film maintains stable mechanical and dielectric properties in long-term high-temperature use.
[0013] Preferably, in the barium titanate potassium niobate composite ceramic particles, the molar ratio of barium titanate (BT) to potassium niobate (KN) is (1.2-1.5):1, and the number average molecular weight of the polyetherimide base film is 20000-30000, and the glass transition temperature is ≥210℃.
[0014] Controlling the BT / KN ratio can optimize the temperature coefficient of the composite material, so that the material maintains stable dielectric constant in a wide temperature range; higher molecular weight and high glass transition temperature give the PEI base excellent heat resistance and mechanical properties, ensuring that the film is not easily softened or deformed in a high-temperature environment.
[0015] A method for manufacturing a temperature adaptive thin film capacitor material, a temperature adaptive thin film capacitor material based on the above, comprising: S1, raw material pretreatment: BT-KN composite ceramic particle preparation: mix barium titanate and potassium niobate according to a predetermined ratio, fully contact the particles of the two by ball milling, and then form BT-KN composite ceramic particles with synergistic dielectric properties through high-temperature sintering; PEI particle pretreatment: dry treatment is performed on the PEI particles to remove moisture and volatile impurities contained in the particles, so as to avoid the formation of bubbles or pinholes due to the volatilization of impurities in the subsequent film forming process; S2, slurry preparation: PEI solution preparation: dissolve the pretreated PEI particles in a suitable solvent to form a uniform and transparent PEI solution; composite slurry preparation: add BT-KN composite ceramic particles and a dispersant to the PEI solution, and uniformly disperse the BT-KN composite ceramic particles in the PEI solution by stirring and ultrasonic dispersion to form a uniform and stable film forming slurry without agglomeration; S3, casting film forming: form a continuous wet film on a support film by casting the film forming slurry; S4, curing and shaping: the wet film formed by casting is cured by stepwise temperature rising, the solvent in the wet film is removed at a low temperature stage, and the PEI molecular chain is crosslinked and cured at a high temperature stage, while the PEI is prevented from being oxidized and the BT-KN composite ceramic particles are prevented from being deteriorated under the protection of inert gas, to form a temperature adaptive thin film capacitor material. After curing, the composite film is peeled off from the support film.
[0016] The composite ceramic particles with stable crystal phase structure are formed by ball milling and sintering; the dry treatment ensures that the PEI solution is pure and free of bubbles; the uniform dispersion of the ceramic particles is achieved by stirring and ultrasonic dispersion; the casting film forming ensures the uniform thickness of the thin film; the stepwise curing removes the solvent while preventing the film layer from shrinking and deforming, and prevents the material from being oxidized by the protection of inert gas, so that a temperature adaptive thin film with dense structure and stable performance is finally obtained.
[0017] Preferably, in the S1, raw material pretreatment, the ball milling adopts an inert material ball mill tank and grinding balls to avoid the introduction of metal impurities during the ball milling process.
[0018] The use of inert materials can avoid the pollution of ceramic particles by metal impurities, ensure the high purity and high insulation of the material, and reduce the dielectric loss and leakage risk caused by impurities.
[0019] Preferably, in the S2, slurry preparation, the dispersant is added in the form of pre-dissolution and dropwise addition, the dispersant is dissolved in a small amount of suitable solvent to form a dispersant solution, and then slowly added into the PEI solution to form a mixed system of BT-KN composite ceramic particles.
[0020] The pre-dissolution can make the dispersant uniformly distributed in the system, avoid local concentration too high leading to particle agglomeration, and further optimize the dispersion effect.
[0021] Preferably, the S3, the casting film forming needs to be defoaming treatment before casting, to remove the bubbles contained in the slurry, to prevent the film layer from appearing bubble defects after casting film forming.
[0022] The defoaming treatment can eliminate the bubbles in the film layer, avoid local discharge or breakdown under the action of electric field, and improve the reliability and life of the capacitor.
[0023] Preferably, the S4, the temperature and time of each stage of the stepwise temperature curing are controlled to ensure that the solvent is gradually removed without causing the film layer to shrink and deform, and the performance of the cured material is detected to ensure that the dielectric uniformity, mechanical integrity and temperature self-adaptive performance meet the requirements, so that it can be used for subsequent manufacturing of thin film capacitors.
[0024] The stepwise curing ensures that the solvent is fully volatilized and the PEI molecular chain is fully crosslinked, avoiding film layer cracking or deformation caused by rapid heating; the performance detection can screen out unqualified products, ensuring that the final capacitor has stable electrical and mechanical properties.
[0025] Compared with the prior art, the temperature self-adaptive thin film capacitor material and manufacturing method provided by the present application has the following beneficial effects: The temperature self-adaptive thin film capacitor material and manufacturing method provided by the present application has the following beneficial effects: The polyetherimide base provides stable mechanical support and insulation, the barium titanate potassium niobate composite ceramic particles are uniformly dispersed, the positive temperature coefficient effect and low temperature dielectric properties are synergistic, the dielectric constant is stable in a wide temperature range; the dispersant forms molecular-level dispersion at the interface, improves compatibility, prevents agglomeration and reduces dielectric loss; the antioxidant is embedded in the PEI molecular chain to inhibit oxidative degradation and maintain long-term stability.
[0026] During manufacturing, the BT-KN is ball milled and sintered into a stable crystal phase, the PEI is dried to remove water and impurities to prevent film forming bubbles; the PEI solution is added with ceramic particles and dispersant, stirred and ultrasonicated to obtain a stable slurry without agglomeration; the continuous wet film is cast to maintain uniform thickness; the stepwise curing removes the solvent, promotes crosslinking to prevent deformation, and inert gas prevents oxidation, finally obtaining a thin film with a dense structure and stable performance, which takes into account the basic performance and wide temperature dielectric stability, reduces loss and prolongs life, and ensures product consistency. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 The figure is a flowchart of the method of the present application. DETAILED DESCRIPTION
[0028] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below, obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.
[0029] The present application provides a technical solution, please refer to Figure 1 A temperature adaptive thin film capacitor material, comprising: a polyetherimide base film as a substrate support and barium titanate potassium niobate composite ceramic particles, the barium titanate potassium niobate composite ceramic particles are uniformly distributed in the interior of the polyetherimide base film in a discrete manner, the interior of the polyetherimide base film contains a dispersant and an antioxidant, the dispersant is distributed in the interface region of the polyetherimide base film PEI molecular chain and the barium titanate potassium niobate composite ceramic particles, forming molecular level dispersion, the antioxidant molecules are uniformly embedded between the PEI molecular chains of the polyetherimide base film, and cannot be chemically bonded with PEI and composite ceramic particles.
[0030] The polyetherimide base film provides stable mechanical support and insulation performance, the barium titanate potassium niobate composite ceramic particles are uniformly dispersed in the interior, the positive temperature coefficient (PTC) effect of barium titanate and the low temperature dielectric property of potassium niobate are synergistically used to make the material keep the dielectric constant stable in a wide temperature range; the dispersant improves the interface compatibility of the ceramic particles and the polymer substrate, avoids agglomeration and reduces dielectric loss; the antioxidant inhibits the oxidative degradation of the PEI molecular chain during preparation and use, thereby ensuring the long-term stability of the material.
[0031] The polyetherimide base film is a uniform film layer structure without bubbles and pinholes, the PEI molecular chains in the interior are partially oriented, the surface roughness is low and flat, the barium titanate potassium niobate composite ceramic particles are spherical, the particle size distribution is narrow, the interior is composed of barium titanate phase and potassium niobate phase, a clear phase interface is formed between the two phases, and an organic coupling agent modified layer is arranged on the surface of the particles.
[0032] The structure without bubbles and pinholes ensures the high insulation of the film and uniform electric field distribution; the partially oriented PEI molecular chains improve the mechanical strength and dimensional stability of the film; the spherical and narrow particle size distribution of the composite ceramic particles are beneficial to uniform dispersion and reduce local electric field concentration; the clear phase interface and the surface coupling agent modified layer further optimize the ceramic / polymer interface bonding, reduce the interface polarization loss, thereby improving the overall performance of the capacitor.
[0033] The organic coupling agent modified layer is a monolayer formed by silane coupling agent and titanate coupling agent, and the interface region is formed by mutual penetration of PEI molecular chains and coupling agent modified layer.
[0034] The coupling agent monolayer is combined with the surface of the ceramic particles by chemical bonds, and the other end interacts with the PEI molecular chain, forming strong binding force and good compatibility in the interface area, reducing interface defects and charge accumulation, thereby reducing dielectric loss and improving the breakdown resistance of the material.
[0035] The dispersant is glycerol tristearate, and the antioxidant is pentaerythritol tetra (ethylhexanoate).
[0036] Glycerol tristearate can effectively reduce the van der Waals force between ceramic particles, prevent agglomeration, and make the particles uniformly distributed in the PEI matrix; as a high-efficiency antioxidant, pentaerythritol tetra (ethylhexanoate) can capture free radicals and decompose hydroperoxides, delay the oxidative degradation of the PEI molecular chain, and ensure that the film maintains stable mechanical and dielectric properties during long-term high-temperature use.
[0037] In the barium titanate-potassium niobate composite ceramic particles, the molar ratio of barium titanate (BT) to potassium niobate (KN) is (1.2-1.5):1, and the number average molecular weight of the polyetherimide base film is 20000-30000, and the glass transition temperature is ≥210℃.
[0038] Controlling the BT / KN ratio can optimize the temperature coefficient of the composite material, making the material maintain stable dielectric constant in a wide temperature range; higher molecular weight and high glass transition temperature endow the PEI base with excellent heat resistance and mechanical properties, ensuring that the film does not soften or deform in a high-temperature environment.
[0039] A manufacturing method of a temperature self-adaptive film capacitor material, based on the above-mentioned temperature self-adaptive film capacitor material, comprising: S1, raw material pretreatment: BT-KN composite ceramic particle preparation: mix barium titanate and potassium niobate according to a predetermined ratio, make the two particles fully contact by ball milling, and then sinter at high temperature to form BT-KN composite ceramic particles with synergistic dielectric properties; PEI particle pretreatment: dry the PEI particles to remove water and volatile impurities contained in the particles to avoid the formation of bubbles or pinholes due to the volatilization of impurities in the subsequent film forming process; S2, slurry preparation: PEI solution preparation: dissolve the pretreated PEI particles in a suitable solvent to form a uniform and transparent PEI solution; composite slurry preparation: add BT-KN composite ceramic particles and dispersant to the PEI solution, and combine stirring and ultrasonic dispersion to make the BT-KN composite ceramic particles uniformly dispersed in the PEI solution to form a uniform and stable film-forming slurry without agglomeration; S3, casting film forming: form a continuous wet film on the support film by casting process; S4, curing and shaping: the wet film formed by casting is cured by stepwise temperature rising. The solvent in the wet film is removed through the low-temperature stage, and the cross-linking of the PEI molecular chain is promoted through the high-temperature stage. Meanwhile, the PEI oxidation and the BT-KN composite ceramic particles are prevented from being deteriorated under the protection of inert gas, so as to form a temperature self-adaptive thin film capacitor material. After curing, the composite film is peeled off from the supporting film.
[0040] The composite ceramic particles with stable crystal phase structure are formed by ball milling and sintering; the dry treatment ensures that the PEI solution is pure and free of bubbles; the combination of stirring and ultrasonic dispersion realizes the uniform dispersion of the ceramic particles; the casting film ensures the uniform thickness of the film; the stepwise curing removes the solvent while avoiding the shrinkage and deformation of the film layer, and prevents the material from being oxidized through the protection of inert gas, so as to finally obtain a temperature self-adaptive thin film with compact structure and stable performance.
[0041] In the raw material pretreatment, the ball milling adopts the ball milling tank and the grinding ball made of inert materials, so as to avoid the introduction of metal impurities in the ball milling process.
[0042] The use of inert materials can avoid the pollution of ceramic particles by metal impurities, ensure the high purity and high insulation of the material, and reduce the dielectric loss and the risk of leakage caused by impurities.
[0043] In the slurry preparation, the dispersant is added by the way of pre-dissolution and dropwise addition. The dispersant is dissolved in a small amount of suitable solvent to form a dispersant solution, and then slowly added into the PEI solution to enter the mixed system of the BT-KN composite ceramic particles.
[0044] The pre-dissolution and dropwise addition can make the dispersant uniformly distributed in the system, avoid the agglomeration of particles caused by too high local concentration, and further optimize the dispersion effect.
[0045] In the casting film forming, the film forming slurry needs to be deaerated before casting to remove the bubbles contained in the slurry and prevent the film layer from having bubble defects after casting film forming.
[0046] The deaeration treatment can eliminate the bubbles in the film layer, avoid the occurrence of partial discharge or breakdown under the action of electric field, and improve the reliability and life of the capacitor.
[0047] In the curing and shaping, the temperature and time of each stage of the stepwise temperature rising curing are controlled to ensure that the solvent is gradually removed without causing the shrinkage and deformation of the film layer. After the performance detection of the cured material, it is ensured that the dielectric uniformity, mechanical integrity and temperature self-adaptive performance meet the requirements, so that it can be used for the subsequent manufacturing of thin film capacitors.
[0048] The stepwise curing ensures that the solvent is fully volatilized and the PEI molecular chain is fully cross-linked, avoiding the cracking or deformation of the film layer caused by rapid temperature rising; the performance detection can screen out unqualified products, ensuring that the final capacitor has stable electrical and mechanical properties.
[0049] It has to be noted that, in the present document, the terms "first", "second", etc. merely serve to identify a subject or action, without necessarily requiring or implying any such actual relationship or order between such subjects or actions. Moreover, the terms "comprising", "containing", or any other similar term are intended to encompass non-exclusive inclusions, such that a process, method, article, or apparatus that comprises a list of elements does not include those elements solely, but can include other elements not expressly listed, or can include elements inherent in such process, method, article, or apparatus.
[0050] While embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, combinations, and variations can be undertaken by those skilled in the art without departing from the spirit and scope of the present application, which is defined by the appended claims and their equivalents.
Claims
1. A temperature adaptive thin film capacitor material, characterized in that, Comprise: As the base support polyetherimide base film and barium titanate potassium niobate composite ceramic particles, the barium titanate potassium niobate composite ceramic particles are uniformly distributed in the interior of the polyetherimide base film in a discrete manner, the interior of the polyetherimide base film contains a dispersant and an antioxidant, the dispersant is distributed in the interface region of the polyetherimide base film PEI molecular chain and the barium titanate potassium niobate composite ceramic particles, and the antioxidant molecules are uniformly embedded between the PEI molecular chains of the polyetherimide base film.
2. The temperature adaptive thin film capacitor material of claim 1, wherein: The polyetherimide base film is a uniform film layer structure without bubbles and pinholes, the interior PEI molecular chain is partially oriented, the barium titanate potassium niobate composite ceramic particles are spherical, the interior is composed of barium titanate phase and potassium niobate phase, and the particle surface is coated with an organic coupling agent modified layer.
3. A temperature adaptive thin film capacitor material according to claim 2, wherein: The organic coupling agent modified layer is a monolayer formed by silane coupling agent and titanate coupling agent, and the interface region is formed by mutual penetration of PEI molecular chain and coupling agent modified layer.
4. The temperature adaptive thin film capacitor material of claim 1, wherein: The dispersant is glycerol tristearate, and the antioxidant is pentaerythritol tetra (ethylhexanoate).
5. The temperature adaptive thin film capacitor material of claim 1, wherein: In the barium titanate potassium niobate composite ceramic particles, the molar ratio of barium titanate (BT) to potassium niobate (KN) is (1.2-1.5):1, and the number average molecular weight of the polyetherimide base film is 20000-30000, and the glass transition temperature is greater than or equal to 210 DEG C.
6. A method of manufacturing a temperature adaptive thin film capacitor material, based on a temperature adaptive thin film capacitor material according to any one of claims 1 to 5, characterized in that Comprise: S1, raw material pretreatment: BT-KN composite ceramic particle preparation: mix barium titanate and potassium niobate according to the preset ratio, fully contact the two particles by ball milling, and then sinter at high temperature to form BT-KN composite ceramic particles with synergistic dielectric properties; PEI particle pretreatment: dry treatment of PEI particles to remove water and volatile impurities contained in the particles; S2, slurry preparation: PEI solution preparation: dissolve the pretreated PEI particles in a suitable solvent to form a uniform transparent PEI solution; Composite slurry preparation: add BT-KN composite ceramic particles and dispersant to the PEI solution, and uniformly disperse the BT-KN composite ceramic particles in the PEI solution by stirring and ultrasonic dispersion to form a uniform and stable film forming slurry without agglomeration; S3, flow casting: Form a continuous wet film on the support film by flow casting process; S4, curing and shaping: The wet film formed by flow casting is cured by stepwise temperature rising, the solvent in the wet film is removed by low temperature stage, and the PEI molecular chain is crosslinked and cured by high temperature stage, and the PEI is prevented from being oxidized and the BT-KN composite ceramic particles are prevented from being deteriorated under the protection of inert gas, forming a temperature adaptive thin film capacitor material, and the composite film is separated from the support film after curing.
7. The method of claim 6, wherein: In the S1, raw material pretreatment, the ball milling adopts an inert material ball mill tank and grinding balls.
8. The method of claim 6, wherein the temperature adaptive thin film capacitor material is formed by: In the S2, slurry preparation, the dispersant is added by pre-dissolving and then dropping, the dispersant is dissolved in a small amount of suitable solvent to form a dispersant solution, and then slowly added into the PEI solution to form a mixed system of BT-KN composite ceramic particles.
9. The method of claim 6, wherein the temperature adaptive thin film capacitor material is formed by: The S3, before casting, the film forming slurry needs to be deaerated to remove the bubbles in the slurry, preventing the film layer from having bubble defects after casting.
10. The method of claim 6, wherein: The S4, the temperature and time of each stage of the stepwise temperature curing are controlled to ensure that the solvent is gradually removed without causing the film layer to shrink and deform, and the performance of the cured material is detected to ensure that the dielectric uniformity, mechanical integrity and temperature self-adaptive performance meet the requirements, which is used for subsequent manufacturing of the film capacitor.