Dielectric slurry composition and dielectric ceramic sheet using the same

Abstract

A dielectric slurry composition having improved dispersibility of dielectric particles is provided, thereby improving the mechanical strength of a dielectric ceramic sheet. [Solution] A dielectric slurry composition according to one embodiment includes dielectric particles including BaTiO3, a solvent including ethanol and toluene, a dispersant including polyvinylpyrrolidone, and a binder, and the ratio of the mass of the ethanol to the mass of the toluene may be greater than 1.0 and less than 2.3.

Description

[Technical Field]

[0001] The present invention relates to a dielectric slurry composition and a dielectric ceramic sheet using the same. [Background technology]

[0002] Multilayer ceramic capacitors (MLCCs), a type of multilayer electronic component, are chip-type capacitors that are mounted on printed circuit boards of various electronic products, such as video equipment like liquid crystal displays (LCDs) and plasma display panels (PDPs), computers, smartphones and mobile phones, on-board chargers (OBCs) for electric vehicles, and circuits like DC-DC converters, to charge and discharge electricity.

[0003] To reduce the size and increase the capacitance of multilayer ceramic capacitors, it is necessary to increase the number of layers by thinning the dielectric ceramic sheets that form the dielectric layers. In this case, the thickness deviation, irradiance dispersion, rigidity, etc. of the dielectric ceramic sheets may have a greater impact on the electrical properties of the multilayer ceramic capacitor than when the dielectric sheets are formed thicker. Therefore, to reduce the size and increase the capacitance of multilayer ceramic capacitors, it is important to ensure the dispersion of the dielectric slurry composition that forms the dielectric layers and the strength and chemical resistance of the dielectric ceramic sheets.

[0004] In order to ensure the homogeneity of the dielectric slurry composition, a method of improving dispersion stability by adding a dispersant at the weighing stage can be used, and in the past, attempts have been made to use polyvinyl butyral as a dispersant.

[0005] However, such conventional dispersants have functional groups that can act as hydrogen bond donors at a ratio of about 40 mol% or less in the entire polymer, which may limit their ability to improve the interfacial bonding strength between the binder and the dielectric particles and the mechanical strength of the dielectric ceramic sheet.

[0006] Therefore, there is a need for a method to form a dielectric slurry composition in which the steric hindrance effect between the dispersant and the dispersion stability of the dielectric particles are enhanced by increasing the number of hydrogen bonds between the binder and the dielectric particles or by adjusting the molecular weight of the dispersant, and to use the same to improve the mechanical properties of the dielectric ceramic sheet. Summary of the Invention [Problem to be solved by the invention]

[0007] One of the various objects of the present invention is to provide a dielectric slurry composition that has improved dispersibility of dielectric particles.

[0008] One of the various objects of the present invention is to improve the mechanical strength of a dielectric ceramic sheet.

[0009] However, the object of the present invention is not limited to the above-mentioned contents, and can be more easily understood in the course of describing specific embodiments of the present invention. [Means for solving the problem]

[0010] A dielectric slurry composition according to one embodiment of the present invention includes dielectric particles including BaTiO3, a solvent including ethanol and toluene, a dispersant including polyvinylpyrrolidone, and a binder, and the ratio of the mass of ethanol to the mass of toluene may be greater than 1.0 and less than 2.3.

[0011] A dielectric ceramic sheet according to an embodiment of the present invention includes dielectric particles including BaTiO3, a dispersant including polyvinylpyrrolidone, a binder, and a plasticizer, and the plasticizer can be negatively charged. [Effects of the Invention]

[0012] One of the various advantages of the present invention is that it provides a dielectric slurry composition with improved dispersibility of dielectric particles.

[0013] One of the various effects of the present invention is to improve the mechanical strength of the dielectric ceramic sheet.

[0014] However, the various yet significant advantages and effects of the present invention are not limited to the above, and can be more easily understood in the course of describing specific embodiments of the present invention. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view schematically illustrating a multilayer electronic component according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II' in FIG. [Figure 3] This shows the structural formula of polyvinyl butyral (PVB). [Figure 4] This shows the structural formula of polyvinylpyrrolidone (PVP). [Figure 5] This shows a rough outline of the state of BaTiO3 particles in the dielectric slurry depending on the molecular weight of the PVP dispersant. [Figure 6] 1 is a graph showing the results of analyzing samples of dielectric slurry compositions containing different types of dispersants by Fourier transform infrared spectroscopy. [Figure 7]1 is a graph comparing the dispersion stability and viscosity of a dielectric slurry composition sample in which PVB is added to the dispersant and a dielectric slurry composition sample in which PVP dispersants with different molecular weights are added. [Figure 8] 1 is a graph comparing the particle size distribution of a sample of a dielectric slurry composition in which PVB is added to the dispersant and a sample of a dielectric slurry composition in which PVP dispersants with different molecular weights are added. [Figure 9] 1 is a graph showing the results of analyzing a sample of a dielectric slurry composition to which PVB is added as a binder and a sample of a dielectric slurry composition to which a PVB binder and PVP dispersants having different molecular weights are added, by Fourier transform infrared spectroscopy. [Figure 10] 1 is a graph showing stress-strain curves of dielectric ceramic sheet samples to which different types of dispersants are added. [Figure 11] 1(a) is a graph showing the short rate of a multilayer electronic component including a dielectric layer to which different types of dispersants are added, and FIG. 1(b) is a graph showing the distribution of the breakdown voltage (BDV) of a multilayer electronic component including a dielectric layer to which different types of dispersants are added. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described with reference to specific embodiments and the accompanying drawings. However, the embodiments of the present invention can be modified into several other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Therefore, the shapes and sizes of elements in the drawings may be enlarged or reduced (or highlighted or simplified) for clearer explanation, and elements denoted by the same reference numerals in the drawings are the same elements.

[0017] In addition, in the drawings, parts not relevant to the description are omitted in order to clearly explain the present invention, and the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, so the present invention is not necessarily limited by the drawings. Furthermore, components having the same function within the same concept may be described using the same reference numerals. Furthermore, throughout the specification, when a part "comprises" a certain component, it does not mean that it excludes other components, but that it may further include other components, unless otherwise specified to the contrary.

[0018] In the drawings, the first direction is a direction in which the first internal electrodes and the second internal electrodes are alternately arranged with the dielectric layer sandwiched therebetween, or a thickness T direction. Of the second and third directions perpendicular to the first direction, the second direction can be defined as a length L direction, and the third direction can be defined as a width W direction.

[0019] Dielectric Slurry Composition Figure 3 shows the structural formula of polyvinyl butyral (PVB), Figure 4 shows the structural formula of polyvinylpyrrolidone (PVP), and Figure 5 shows a rough outline of the state of BaTiO3 particles in a dielectric slurry depending on the molecular weight of the PVP dispersant.

[0020] Hereinafter, a dielectric slurry composition according to one embodiment of the present invention and various embodiments thereof will be described in detail with reference to FIGS.

[0021] A dielectric slurry composition according to one embodiment of the present invention may include dielectric particles 11 including BaTiO 3 , a solvent 21 including ethanol and toluene, a dispersant 12 including polyvinylpyrrolidone, and a binder 22.

[0022] The dielectric particles 11 can contain BaTiO3 and can be the main component of the dielectric layer of the multilayer electronic component. The dielectric particles 11 can contain not only BaTiO3 but also (Ba 1-x Ca x )TiO3 (0 < x < 1), Ba(Ti 1-y Ca y )O3 (0 < y < 1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (0 < x < 1, 0 < y < 1) or Ba(Ti 1-y Zr y )O3 (0 < y < 1), etc. can be further included.

[0023] The dielectric particles 11 contained in the dielectric slurry composition need to be uniformly and stably dispersed in the dielectric slurry composition and need to sufficiently interact with other components in the dielectric slurry composition to form a dielectric ceramic sheet. Therefore, the dielectric slurry composition can contain a ceramic additive, a solvent 21, a dispersant 12, a binder 22, etc.

[0024] Referring to FIG. 4, polyvinylpyrrolidone has a functional group that serves as a hydrogen bond acceptor for each monomer and is a dispersant that is highly miscible with the surface of dielectric particles containing BaTiO3, a binder, and the solvent used in the production of the slurry.

[0025] On the other hand, referring to FIG. 3, a dispersant containing conventional polyvinyl butyral (PVB) has a carbonyl group (C=O) of monomer x and a hydroxyl group (-OH) of monomer y serving as hydrogen bond acceptors. Referring to FIG. 4, polyvinylpyrrolidone has all functional groups within the polymer chain capable of forming hydrogen bonds.

[0026] Therefore, when the dielectric slurry composition contains a dispersant containing polyvinylpyrrolidone as in one embodiment of the present invention, the interfacial adhesion between the binder and the dielectric particles can be increased, thereby improving the mechanical strength of the dielectric ceramic sheet.

[0027] Dispersants containing polyvinylpyrrolidone have excellent miscibility with ethanol-rich dispersants. Therefore, in one embodiment of the present invention, the ratio of the mass of ethanol to the mass of toluene in a solvent 21 containing ethanol and toluene can be greater than 1.0.

[0028] On the other hand, if the ratio of the mass of ethanol to the mass of toluene is 2.3 or more, the specific gravity of toluene, which is a non-polar solvent, in the total solvent may be excessive, which may cause precipitation of dielectric particles. Therefore, in one embodiment of the present invention, the ratio of the mass of ethanol to the mass of toluene may be less than 2.3.

[0029] As an example of a method for measuring the mass ratio of ethanol to the mass of toluene in the dielectric slurry composition, the dielectric slurry composition can be filtered to obtain only the solvent, and then the contents of toluene and ethanol in the solvent can be analyzed using GC-MS (Gas Chromatography-Mass Spectrometry), and the mass ratio can be calculated based on the result.

[0030] In one embodiment, a dispersant 12 containing polyvinylpyrrolidone may be disposed on the surface of the dielectric particles 11, and whether or not the dispersant 12 containing polyvinylpyrrolidone is disposed on the surface of the dielectric particles 11 may be confirmed by detecting whether or not nitrogen (N) elements are detected on the surface of the dispersant using a TEM-EDS (Transmission Electron Microscopy-Energy Dispersive X-ray Spectroscopy) analysis or an FT-IR (Fourier Transform-Infrared Spectroscopy) analysis method.

[0031] When the dispersant 12 containing polyvinylpyrrolidone is placed on the surface of the dielectric particles 11, the dielectric particles 11 can be uniformly dispersed in the ethanol-toluene solvent 21.

[0032] In the dielectric slurry composition, the molecular weight of the dispersant 12 containing polyvinylpyrrolidone can be another factor affecting the dispersibility of the dielectric particles. If the molecular weight of the dispersant 12 containing polyvinylpyrrolidone is less than 6,300 g / mol, a repulsive force sufficient to withstand the attractive force between the dielectric particles 11 cannot be formed, and the dielectric particles 11 may exist in an aggregated state in the solvent, as shown in Figure 5(a). If the molecular weight of the dispersant 12 containing polyvinylpyrrolidone exceeds 309,000 g / mol, the dispersant chains extending from the surface of the dielectric particle 11 into the solvent may become entangled with the dispersant chains formed on the surface of adjacent dielectric particles, as shown in Figure 5(c). In one embodiment, the molecular weight of the dispersant 12 containing polyvinylpyrrolidone is adjusted to be 6,300 g / mol or more and 309,000 g / mol or less, so that the dielectric particles can be uniformly dispersed in the solvent as shown in (b) of Figure 5.

[0033] The molecular weight of dispersant 12 containing polyvinylpyrrolidone can be measured by gel permeable chromatography (GPC) under the following conditions: Column: PL Aquagel-OH mixed x 2 (300 x 7.5 mm) / 40°C, Flow rate: 0.8 ml / min, Mobile phase solvent: DI water with buffer (0.2 M NaNO3 + 0.01 M Na2HPO4), 30% MeOH, Injection volume: 100 μl, but the present invention is not limited thereto.

[0034] In one embodiment, the Hansen Solubility Parameter Ra of the dispersant 12 included in the dielectric slurry composition may be greater than 13 and less than 16. If the solubility parameter Ra is 13 or less, the dispersant 12 has a greater tendency to dissolve in the solvent than to be located on the surface of the dielectric particles 11, which may result in an insufficient increase in the interfacial force between the dielectric particles 11 and the binder 22. Also, if the Hansen Solubility Parameter Ra of a dispersant containing PVP is 16 or more, aggregation of the binder may occur when the dispersant is mixed with the binder. On the other hand, if the solubility parameter of the dispersant 12 is greater than 13 and less than 16 in the ethanol-toluene solvent 21, as in one embodiment, the dispersant 12 has a greater tendency to be located on the surface of the dielectric particles 11 than to be dissolved in the solvent 21. This not only sufficiently increases the interfacial force between the dielectric particles 11 and the binder 22, but also prevents aggregation or precipitation of the dielectric particles 11, thereby improving the dispersibility of the dielectric slurry composition.

[0035] Meanwhile, the Hansen Solubility Parameter value is a value used to predict the solubility of a substance. HSPs are known for a wide range of solvents, and it can be measured as a function of affinity by testing the solubility of an organic substance in a series of HSP solvents. Using a program called HSPiP (Hansen Solubility Parameters in Practice) developed by Dr. Hansen's group, the optimum can be analyzed and calculated from the results of the solubility test, and the Ra value can be controlled by adjusting the ratio of ethanol and toluene in the solvent.

[0036] In one embodiment, the binder 22 of the dielectric composition may include polyvinyl butyral.

[0037] Polyvinylpyrrolidone dispersant 12 has one carbonyl group (C=O), which is a hydrogen bond acceptor group, per monomer, in addition to hydrophobic interactions, and forms a hydrogen bond with a hydroxyl group (-OH), which is a hydrogen bond donor group, in polyvinyl butyral (PVB) binder 22. On the other hand, when both the dispersant and binder contain polyvinyl butyral, complex interactions occur because both the hydrogen bond acceptor and donor groups are included.

[0038] Therefore, in one embodiment, when the dispersant 12 of the dielectric slurry composition includes polyvinylpyrrolidone and the binder 22 includes polyvinyl butyral, the interaction between the dispersant 12 on the surface of the dielectric particles 11 and the binder 22 can be increased. This can improve dispersion stability compared to when both the dispersant and the binder include polyvinyl butyral.

[0039] Meanwhile, when the dielectric composition includes polyvinylpyrrolidone as the dispersant 12 and polyvinyl butyral as the binder 22, where n is the number of polyvinylpyrrolidone monomers and x is the number of hydroxyl group monomers in polyvinyl butyral (PVB), the ratio n / x can be greater than or equal to 0.67 and less than 3.7. This can improve the interaction between the dispersant and the binder. On the other hand, if the ratio n / x is greater than or equal to 3.7, the dielectric particles may aggregate excessively, making it difficult to control the physical properties of the dielectric sheet. The value of n / x can be adjusted along with the value of C, where C is the molar ratio of the PVP dispersant to the PVB binder multiplied by the number of PVP monomers and the number of hydroxyl group monomers in the PVB binder. Specifically, when the average size of the dielectric particles is 70 nm, the value of C may be 8.5 or more, and when the average size of the dielectric particles is 100 nm, the value of C may be 5.7 or more.

[0040] Dielectric Ceramic Sheet The dielectric slurry composition according to one embodiment of the present invention and the dielectric slurry compositions according to various embodiments thereof can be manufactured into a dielectric ceramic sheet through additional processes.

[0041] The method for preparing the dielectric slurry composition into a dielectric ceramic sheet is not particularly limited, and may be such that a binder and a plasticizer are added to the dielectric slurry composition, and then the composition is applied to a PET (polyethylene terephthalate) film by a doctor blade method, followed by a drying step for removing the solvent inside the dielectric slurry composition.

[0042] The dielectric ceramic sheet according to one embodiment of the present invention may contain substantially the same components as the dielectric slurry composition according to one embodiment of the present invention and various other embodiments, except for the solvent and binder.

[0043] Specifically, the dielectric ceramic sheet may include dielectric particles containing BaTiO3, a dispersant containing polyvinylpyrrolidone, a binder, and a plasticizer. Since the dielectric ceramic sheet includes polyvinylpyrrolidone as a dispersant, the mechanical properties of the dielectric ceramic sheet can be improved.

[0044] Meanwhile, dielectric ceramic sheets containing polyvinylpyrrolidone as a dispersant may contain a plasticizer. If the plasticizer is negatively charged, the absolute magnitude of static electricity generated during peeling can be reduced, thereby reducing defects that occur during lamination of the dielectric ceramic sheets. When the plasticizer is negatively charged, the use of polyvinylpyrrolidone as a dispersant provides a more effective reduction in static electricity generated during peeling than the use of polyvinyl butyral as a dispersant. Therefore, when a dielectric layer of a multilayer electronic component is formed using a dielectric ceramic sheet containing dielectric particles containing BaTiO3, a dispersant containing polyvinylpyrrolidone, a binder, and a negatively charged plasticizer, as in one embodiment of the present invention, the electrical properties of the multilayer electronic component can be improved, such as a reduced short rate and improved breakdown voltage (BDV) distribution.

[0045] On the other hand, examples of negatively charged plasticizers include triglyme, tetraglyme, polyglyme, etc. That is, in one embodiment, the plasticizer may include one or more of triglyme, tetraglyme, polyglyme, etc.

[0046] In one embodiment, by adjusting the molecular weight of the dispersant containing polyvinylpyrrolidone to 6,300 g / mol or more and 309,000 g / mol or less, the dielectric particles can be uniformly dispersed in the dielectric slurry composition, thereby improving the mechanical properties of the dielectric ceramic sheet.

[0047] In one embodiment, the binder of the dielectric ceramic sheet may include polyvinyl butyral, which may increase the interaction between the dispersant on the surface of the dielectric particles and the binder, thereby improving the mechanical properties of the dielectric ceramic sheet compared to when both the dispersant and the binder include polyvinyl butyral.

[0048] In one embodiment, when the dielectric ceramic sheet includes polyvinylpyrrolidone as a dispersant and polyvinyl butyral as a binder, where n is the number of polyvinylpyrrolidone monomers and x is the number of hydroxyl group monomers in polyvinyl butyral (PVB), the ratio n / x may be greater than or equal to 0.67 and less than 3.7. This improves the interaction between the dispersant and the binder, thereby improving the mechanical properties of the dielectric ceramic sheet. If the ratio n / x is greater than or equal to 3.7, the dielectric particles may aggregate excessively, making it difficult to control the physical properties of the dielectric sheet. Meanwhile, the n / x value can be adjusted in conjunction with the C value, where C is the molar ratio of the PVP dispersant to the PVB binder multiplied by the number of PVP monomers and the number of hydroxyl group monomers in the PVB binder. Specifically, when the average size of the dielectric particles is 70 nm, the value of C may be 8.5 or more, and when the average size of the dielectric particles is 100 nm, the value of C may be 5.7 or more.

[0049] 6 is a graph obtained by analyzing samples of dielectric slurry compositions containing different types of dispersants by Fourier transform infrared spectroscopy, FIG. 7 is a graph comparing the dispersion stability and viscosity of a sample of a dielectric slurry composition containing PVB as a dispersant and a sample of a dielectric slurry composition containing PVP dispersants with different molecular weights, FIG. 8 is a graph comparing the particle size distribution of a sample of a dielectric slurry composition containing PVB as a dispersant and a sample of a dielectric slurry composition containing PVP dispersants with different molecular weights, FIG. 9 is a graph obtained by analyzing samples of a dielectric slurry composition containing PVB as a binder and a sample of a dielectric slurry composition containing a PVB binder and PVP dispersants with different molecular weights by Fourier transform infrared spectroscopy, and FIG. 10 is a graph comparing the stress-strain of a sample of a dielectric ceramic sheet containing different types of dispersants. 11(a) is a graph showing the short rate of multilayer electronic components including dielectric layers to which different types of dispersants have been added, and FIG. 11(b) is a graph showing the distribution of the breakdown voltage (BDV) of multilayer electronic components including dielectric layers to which different types of dispersants have been added.

[0050] Hereinafter, experimental examples of a dielectric slurry composition and a dielectric ceramic sheet according to one embodiment will be described in detail with reference to FIGS.

[0051] In each experimental example, a dielectric slurry composition sample was prepared by milling a PVP or PVB dispersant solution (10 wt% in ethanol), BaTiO3 (70 nm) powder, and zirconia beads in a vial containing an EtOH / Tol mixed solvent. Before the milling process was completed, a binder solution was prepared by dissolving the PVB resin in a mixture of ethanol and toluene using ultrasonic treatment until the target viscosity was reached (approximately 2 hours). This was then added to the dielectric slurry composition, and dielectric ceramic sheet samples with a thickness of 0.8 μm or less were fabricated on polyethylene terephthalate (PET) film using a doctor blade.

[0052] (Experimental Example 1) FIG. 6 is a graph showing the results of an analysis of samples of dielectric slurry compositions containing different types of dispersants by Fourier transform infrared spectroscopy.

[0053] Comparative Example 1-1 is a case where dielectric particles containing BaTiO3 were added but no dispersant was added, Comparative Example 1-2 is a case where dielectric particles containing BaTiO3 were added and polyvinyl butyral (PVB) was used as a dispersant, and Example 1-3 is a case where dielectric particles containing BaTiO3 were added and polyvinylpyrrolidone was used as a dispersant.

[0054] Referring to FIG. 6, Comparative Example 1-2 shows peaks in the wave number region (a) corresponding to the acetal group of PVB and in the wave number region (c) corresponding to the methylene group (-CH), and Example 1-3 shows a strong peak in the wave number region (b) corresponding to the carbonyl group (C=0).

[0055] (Experimental Example 2) Figure 7 is a graph comparing the dispersion stability and viscosity of a sample of a dielectric slurry composition to which PVB is added as a dispersant and a sample of a dielectric slurry composition to which PVP dispersants with different molecular weights are added, and Figure 8 is a graph comparing the particle size distribution of a sample of a dielectric slurry composition to which PVB is added as a dispersant and a sample of a dielectric slurry composition to which PVP dispersants with different molecular weights are added.

[0056] 7 and 8, the properties of each comparative example and example are as follows, and the solubility parameter Ra of the dispersant in an ethanol-toluene solvent is 14. Dispersion stability was measured using a disk centrifugal photoprecipitation method (DCP; DC24000 UHR, CPS Instruments, USA) and a LUMiSizer (LUM GmbH, Germany) at a rotation speed of 4000 RPM and a measurement temperature of 25°C to measure the instability index, and viscosity was measured using a micro sample volume viscometer (m-VROC, Rheosense Inc., USA) at a measurement temperature of 25°C. (1) Comparative Example 2-1: Dielectric particles containing BaTiO3 are added, and polyvinyl butyral (PVB) is used as a dispersant. (2) Example 2-4: Dielectric particles containing BaTiO3 were added, and polyvinylpyrrolidone was used as a dispersant. The molecular weight of the polyvinylpyrrolidone dispersant was 6320 g / mol. (3) Example 2-5: Dielectric particles containing BaTiO3 were added, and polyvinylpyrrolidone was used as a dispersant. The molecular weight of the polyvinylpyrrolidone dispersant was 17,700 g / mol. (4) Example 2-6: Dielectric particles containing BaTiO3 were added, and polyvinylpyrrolidone was used as a dispersant. The molecular weight of the polyvinylpyrrolidone dispersant was 27,000 g / mol. (5) Example 2-7: Dielectric particles containing BaTiO3 were added, and polyvinylpyrrolidone was used as a dispersant. The molecular weight of the polyvinylpyrrolidone dispersant was 34100 g / mol. (6) Example 2-8: Dielectric particles containing BaTiO3 were added, and polyvinylpyrrolidone was used as a dispersant. The molecular weight of the polyvinylpyrrolidone dispersant was 309,000 g / mol.

[0057] 7, Comparative Example 2-1 had an instability index of 1.075, while Examples 2-4, 2-5, 2-6, 2-7, and 2-8 had instability indexes of 0.168 or less. Meanwhile, all Comparative Examples and Examples except Example 2-8 had viscosities of 1.7 to 1.8 mPa s. When the effect of viscosity on improving dispersion stability is eliminated, it can be seen that the use of polyvinylpyrrolidone as a dispersant provides a superior improvement in dispersion stability compared to the use of polyvinyl butyral (PVB) as a dispersant.

[0058] Meanwhile, referring to FIG. 8, it can be seen that the D50 of the dielectric particles of the dielectric slurry composition in Example 2-4 was reduced by about 2.5 nm compared to Comparative Example 2-1, but in the case of Example 2-6 with a high molecular weight, the thickness of the dispersant layer disposed on the surface of the dielectric particles was increased, resulting in a D50 value at the same level as in Comparative Example 2-1.

[0059] (Experimental Example 3) FIG. 9 is a graph showing the results of analyzing a sample of a dielectric slurry composition to which PVB was added as a binder and a sample of a dielectric slurry composition to which a PVB binder and PVP dispersants with different molecular weights were added, using Fourier transform infrared spectroscopy. FIG. 10 is a graph showing the stress-strain curves of dielectric ceramic sheet samples to which different types of dispersants were added.

[0060] 9 and 10, the properties of each comparative example and example are as follows, and the solubility parameter Ra of the dispersant in an ethanol-toluene solvent is 14.

[0061] In addition, each of the comparative examples and examples contained dielectric particles containing BaTiO3, and polyvinyl butyral (PVB) was used as a binder.

[0062] For the Fourier Transform Infrared Spectroscopy analysis shown in Figure 9, the dielectric particles were precipitated using a centrifuge (10,000 rpm, 10 min) to remove excess dispersant from the dielectric slurry composition, and then re-dispersed in EtOH. This process was repeated three times. After this, the dielectric particles were completely dried to remove any remaining solvent, and measurements were performed using a light source with a beam size of 70 μm (depth: 3-5 μm).

[0063] To analyze the tensile strength of the dielectric ceramic sheet using a dynamic mechanical analyzer (DMA) as shown in Figure 10, dispersants were mixed in the same proportion as the binder solution and coated on a PET film to produce a sheet. DMA measurements measured strain rate and stress, and dumbbell-shaped specimens were cut from the dielectric sheet in the casting direction using a sample cutter. Tensile tests were performed at a speed of 0.1 mm / s, and a minimum of four samples were tested to calculate the average tensile properties of the sheet. (1) Comparative Example 3-1: No dispersant used (2) Example 3-1: Polyvinyl butyral is used as a dispersant (3) Example 3-2: Using a polyvinylpyrrolidone dispersant with a molecular weight of 6320 g / mol (4) Example 3-3: Using a polyvinylpyrrolidone dispersant with a molecular weight of 27,000 g / mol

[0064] Referring to FIG. 9, as the molecular weight of the polyvinylpyrrolidone dispersant increases, the peak at 3100 cm corresponding to the hydroxyl group (-OH) of the binder increases. -1 ~3700cm -1 It can be seen that the peak in the range shifts to a lower wavenumber, which indicates that the interaction between the dispersant and the binder increases as the molecular weight of the dispersant (Polyvinylpyrrolidone) increases.

[0065] Referring to FIG. 10, it can be seen that the yield strength of the dielectric ceramic sheet is higher when polyvinylpyrrolidone dispersant is used than when no dispersant or polyvinyl butyral is used as a dispersant, and it can be seen that the yield strength of the dielectric ceramic sheet tends to improve as the molecular weight of the polyvinylpyrrolidone dispersant increases.

[0066] (Experimental Example 4) FIG. 11(a) is a graph showing the short rate of multilayer electronic components including dielectric layers to which different types of dispersants were added, and FIG. 11(b) is a graph showing the distribution of breakdown voltage (BDV) of multilayer electronic components including dielectric layers to which different types of dispersants were added.

[0067] The characteristics of the comparative examples and examples are as follows. The multilayer electronic components were manufactured by printing an internal electrode paste on a dielectric ceramic sheet, stacking the individual sheets to form a multilayer sheet, sintering the multilayer sheet at a temperature to achieve the same capacitance, and then forming external electrodes through a termination process.

[0068] The short rate was measured when a total DC voltage of 500mV at 120Hz was applied to a total of 30 samples of laminated electronic components to cause a short circuit, and the dielectric breakdown voltage (BDV) was measured using an HV BDV tester (PR12PF) by increasing the voltage from 0V at a rate of 50V / sec until chip breakdown. (1) Comparative Example 4-1: Manufacturing a multilayer electronic component using a dielectric slurry composition containing dielectric particles containing BaTiO3 and using polyvinyl butyral as a dispersant. (2) Example 4-1: Manufacture of a multilayer electronic component using a dielectric slurry composition containing dielectric particles containing BaTiO3 and using polyvinylpyrrolidone with a molecular weight of 27,000 g / mol as a dispersant.

[0069] (Experimental Example 5) Table 1 below shows the peeling force and static electricity generated during peeling measured for each dispersant depending on the type of plasticizer.

[0070] The peel strength and static electricity were measured by forming a dielectric ceramic sheet on a substrate according to the type of dispersant and plasticizer classified as follows, and then using a peel strength tester (90° peel test) and a static electricity tester at a measurement temperature of 25°C and a peel speed of 300mm / min.

[0071] Dioctyl adipate (DOA) was used as the positively charged plasticizer, and tetraglyme was used as the negatively charged plasticizer.

[0072] [Table 1]

[0073] Referring to Table 1, when the plasticizer applied to the dielectric ceramic sheet has a negative charge (-), it can be seen that the absolute magnitude of static electricity generated during peeling is reduced when a PVP dispersant is used compared to when a PVB dispersant is used, thereby reducing defects that occur during lamination.

[0074] (Experimental Example 6) Table 2 below shows the dispersibility of the dielectric slurry composition for each molecular weight of the PVP dispersant and the mechanical properties of the dielectric ceramic sheet.

[0075] [Table 2]

[0076] Referring to Table 2, it can be seen that when the molecular weight of the PVP dispersant is between 6,300 g / mol and 309,000 g / mol, no aggregation occurs in the dielectric slurry composition. On the other hand, when the molecular weight of the PVP dispersant is between 63,200 g / mol and 309,000 g / mol, no aggregation occurs in the entire slurry composition and the instability index is 0.168 or less, confirming excellent dispersion stability. On the other hand, when the molecular weight of the PVP dispersant is between 17,700 g / mol and 34,100 g / mol, it can be seen that the mechanical properties of the dielectric ceramic sheet are improved. In Table 2, an instability index value of more than 1.7 is indicated as NG, and the mechanical properties are evaluated as OK when the elastic modulus is 15 MPa or more and the strain value is 10% or more, and NG otherwise.

[0077] Multilayer electronic components FIG. 1 is a schematic perspective view of a multilayer electronic component, and FIG. 2 is a schematic cross-sectional view taken along line II' in FIG.

[0078] Hereinafter, a multilayer electronic component manufactured by a method for manufacturing a multilayer electronic component according to an embodiment of the present invention will be described in detail with reference to Figures 1 and 2. Although a multilayer ceramic capacitor will be described as an example of a multilayer electronic component, the present invention can also be applied to various electronic products that use a dielectric composition, such as an inductor, a piezoelectric element, a varistor, or a thermistor.

[0079] The body 110 is formed by alternately laminating dielectric layers 111 and internal electrodes 121 and 122 .

[0080] More specifically, the main body 110 may include a capacitance forming portion that is disposed inside the main body 110 and includes first internal electrodes 121 and second internal electrodes 122 that are alternately arranged facing each other across the dielectric layer 111 to form a capacitance.

[0081] Although there is no particular limitation on the specific shape of the body 110, the body 110 may be hexahedral or a similar shape as shown in the figure. Due to shrinkage of the ceramic powder contained in the body 110 during the firing process, the body 110 may not be a hexahedral shape with perfectly straight lines, but may have a substantially hexahedral shape.

[0082] The main body 110 may have a first surface 1 and a second surface 2 facing each other in a first direction, a third surface 3 and a fourth surface 4 connected to the first surface 1 and the second surface 2 and facing each other in the second direction, and a fifth surface 5 and a sixth surface 6 connected to the first surface 1, the second surface 2, the third surface 3 and the fourth surface 4 and facing each other in the third direction.

[0083] The plurality of dielectric layers 111 forming the body 110 are in a sintered state, and the boundaries between adjacent dielectric layers 111 can be integrated to the extent that they are difficult to see without using a scanning electron microscope (SEM).

[0084] The raw material for forming the dielectric layer 111 is not limited as long as sufficient capacitance can be obtained. Generally, perovskite (ABO3) - based materials can be used. For example, barium titanate - based materials, lead - composite perovskite - based materials, or strontium titanate - based materials can be used. The barium titanate - based materials can contain BaTiO3 - based ceramic powders. Examples of the ceramic powders include BaTiO3, (Ba 1-x Ca x )TiO3 (0 < x < 1), Ba(Ti 1-y Ca y )O3 (0 < y < 1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (0 < x < 1, 0 < y < 1) or Ba(Ti 1-y Zr y )O3 (0 < y < 1), etc. 。

[0085] Also, various ceramic additives, organic solvents, binders, dispersants, etc. can be added to the powders such as barium titanate (BaTiO3) according to the purpose of the present invention as the raw material for forming the dielectric layer 111.

[0086] The internal electrodes 121 and 122 may be alternately laminated with the dielectric layer 111.

[0087] The internal electrodes 121 and 122 can include a first internal electrode 121 and a second internal electrode 122. The first internal electrode 121 and the second internal electrode 122 are alternately arranged so as to face each other with the dielectric layer 111 constituting the main body 110 interposed therebetween, and can be respectively exposed on the third surface 3 and the fourth surface 4 of the main body 110.

[0088] More specifically, the first internal electrode 121 may be spaced apart from the fourth surface 4 and exposed through the third surface 3, and the second internal electrode 122 may be spaced apart from the third surface 3 and exposed through the fourth surface 4. A first external electrode 131 may be disposed on the third surface 3 of the body 110 and connected to the first internal electrode 121, and a second external electrode 132 may be disposed on the fourth surface 4 of the body 110 and connected to the second internal electrode 122.

[0089] That is, the first internal electrode 121 may be connected to the first external electrode 131 but not to the second external electrode 132, and the second internal electrode 122 may be connected to the second external electrode 132 but not to the first external electrode 131. In this case, the first internal electrode 121 and the second internal electrode 122 may be electrically isolated from each other by the dielectric layer 111 disposed therebetween.

[0090] Meanwhile, the body 110 may be formed by alternately stacking ceramic green sheets on which the first internal electrodes 121 are printed and ceramic green sheets on which the second internal electrodes 122 are printed, and then firing the stacked sheets.

[0091] There are no particular limitations on the material forming the internal electrodes 121 and 122, and any material with excellent electrical conductivity can be used. For example, the internal electrodes 121 and 122 can include one or more of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof.

[0092] The internal electrodes 121 and 122 may be formed by printing an internal electrode conductive paste containing one or more of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof onto a ceramic green sheet. The internal electrode conductive paste may be printed by screen printing or gravure printing, but the present invention is not limited thereto.

[0093] Meanwhile, the main body 110 may include cover portions 112 and 113 disposed on both end surfaces of the capacitance forming portion in the first direction.

[0094] More specifically, it may include an upper cover part 112 disposed at an upper part of the capacitance forming part in the first direction and a lower cover part 113 disposed at a lower part of the capacitance forming part in the first direction.

[0095] The upper cover part 112 and the lower cover part 113 may be formed by stacking a single dielectric layer 111 or two or more dielectric layers 111 in a first direction on the upper and lower surfaces of the capacitance forming part, respectively, and may basically serve to prevent damage to the internal electrodes 121, 122 due to physical or chemical stress.

[0096] The upper cover part 112 and the lower cover part 113 do not include the internal electrodes 121, 122 and may include the same material as the dielectric layer 111. That is, the upper cover part 112 and the lower cover part 113 may include a ceramic material, for example, a barium titanate (BaTiO)-based ceramic material.

[0097] Meanwhile, margin portions may be disposed on both end surfaces of the body 110 in the third direction.

[0098] More specifically, the margin portion may include a first margin portion disposed on the fifth surface 5 of the main body 110 and a second margin portion disposed on the sixth surface 6. That is, the margin portions may be disposed on both end surfaces of the main body 110 in the third direction.

[0099] The margin portion may refer to the area between both ends of the first internal electrode 121 and the second internal electrode 122 in the third direction and the boundary surface of the body 110, based on the cross-section of the body 110 in the second and third directions.

[0100] The margin portion basically serves to prevent damage to the internal electrodes 121 and 122 due to physical or chemical stress.

[0101] The margin portion can be formed by applying a conductive paste to the ceramic green sheet except for the area where the margin portion is to be formed to form internal electrodes 121, 122, and then cutting the laminated internal electrodes 121, 122 so that they are exposed on the fifth surface 5 and the sixth surface 6 of the main body 110 in order to suppress steps caused by the internal electrodes 121, 122, and then stacking a single dielectric layer 111 or two or more dielectric layers 111 in the third direction on both end surfaces in the third direction of the capacitance forming portion.

[0102] In one embodiment of the present invention, a structure in which the ceramic electronic component 100 has two external electrodes 131, 132 is described, but the number and shape of the external electrodes 131, 132 can be changed depending on the shape of the internal electrodes 121, 122 and other purposes.

[0103] The outer electrodes 131 and 132 may be disposed on the body 110 and connected to the inner electrodes 121 and 122 .

[0104] More specifically, the external electrodes 131, 132 may include a first external electrode 131 and a second external electrode 132 disposed on the third surface 3 and the fourth surface 4 of the body 110, respectively, and connected to the first internal electrode 121 and the second internal electrode 122, respectively. That is, the first external electrode 131 may be disposed on the third surface 3 of the body and connected to the first internal electrode 121, and the second external electrode 132 may be disposed on the fourth surface 4 of the body and connected to the second internal electrode 122.

[0105] The external electrodes 131 and 132 may be formed using any material that has electrical conductivity, such as a metal, and the specific material may be determined taking into consideration electrical properties, structural stability, etc., and may further have a multi-layer structure.

[0106] For example, the external electrodes 131 and 132 may include electrode layers 131a and 132a disposed on the main body 110 and plating layers 131b and 132b disposed on the electrode layers 131a and 132a.

[0107] As a more specific example of the electrode layers 131a and 132a, the electrode layers 131a and 132a may be fired electrodes containing a conductive metal and glass, or resin-based electrodes containing a conductive metal and resin.

[0108] The electrode layers 131a and 132a may also be in a form in which a fired electrode and a resin-based electrode are sequentially formed on the main body 110.

[0109] In addition, the electrode layers 131a and 132a may be formed by transferring a sheet containing a conductive metal onto the main body 110, or by transferring a sheet containing a conductive metal onto a fired electrode.

[0110] The conductive metal used for the electrode layers 131a and 132a is not particularly limited as long as it can be electrically connected to the internal electrodes 121 and 122 to form capacitance, and may include, for example, one or more selected from the group consisting of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (At), platinum (At), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof. The electrode layers 131a and 132a may be formed by applying a conductive paste prepared by adding glass frit to the conductive metal powder, followed by firing.

[0111] The plating layers 131b and 132b serve to improve the mounting characteristics.

[0112] The type of plating layers 131b, 132b is not particularly limited, and may be a single layer plating layer 131b, 132b containing one or more of nickel (Ni), tin (Sn), palladium (Pd), and alloys thereof, or may be formed of multiple layers.

[0113] As a more specific example of the plating layers 131b and 132b, the plating layers 131b and 132b may be Ni plating layers or Sn plating layers, or may be formed in a form in which a Ni plating layer and a Sn plating layer are sequentially formed on the electrode layers 131a and 132a, or in a form in which a Sn plating layer, a Ni plating layer, and a Sn plating layer are sequentially formed. Also, the plating layers 131b and 132b may include multiple Ni plating layers and / or multiple Sn plating layers.

[0114] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and the accompanying drawings, but is limited by the scope of the accompanying claims. Therefore, various substitutions, modifications, and changes may be made by a person skilled in the art without departing from the technical spirit of the present invention as set forth in the claims, and these also fall within the scope of the present invention.

[0115] Furthermore, the phrase "one embodiment" used in this disclosure does not mean the same embodiment, but is provided to emphasize and describe each unique feature that is different from the others. However, the above-described one embodiment does not exclude being realized in combination with features of another embodiment. For example, even if a feature described in one embodiment is not described in another embodiment, it can be understood as a description related to the other embodiment unless there is a description in the other embodiment that contradicts or contradicts the feature.

[0116] The terms used in this disclosure are merely used to describe one embodiment and are not intended to limit the disclosure. In this case, singular expressions include plural expressions unless the context clearly indicates otherwise. [Explanation of symbols]

[0117] 100 Multilayer electronic components 110 Main Unit 111 Dielectric layer 121, 122 Internal electrode 112, 113 Cover 114, 115 Margin 131, 132 External electrode 21 Solvent 22 Binder 11 Dielectric particles 12 Dispersants

Claims

1. BaTiO ３ a solvent including ethanol and toluene, a dispersant including polyvinylpyrrolidone, and a binder; A dielectric slurry composition, wherein the ratio of the mass of the ethanol to the mass of the toluene is greater than 1.0 and less than 2.

3.

2. 2. The dielectric slurry composition according to claim 1, wherein the molecular weight of the polyvinylpyrrolidone is 6,300 g / mol or more and 309,000 g / mol or less.

3. The dielectric slurry composition of claim 1 , wherein the dispersant has a Hansen Solubility Parameter of more than 13 and less than 16.

4. The dielectric slurry composition according to claim 1 , wherein the dispersant is disposed on the surfaces of the dielectric particles.

5. The dielectric slurry composition according to claim 1 , wherein nitrogen (N) elements are disposed on the surfaces of the dielectric particles.

6. The dielectric slurry composition of claim 1 , wherein the binder comprises polyvinyl butyral.

7. 7. The dielectric slurry composition according to claim 6, wherein n / x is 0.67 or more and less than 3.7, where n is the number of monomers of the polyvinylpyrrolidone and x is the number of monomers of hydroxyl groups contained in the polyvinyl butyral.

8. BaTiO ３ a dispersant including polyvinylpyrrolidone, a binder, and a plasticizer; The plasticizer carries a negative charge.

9. The dielectric ceramic sheet according to claim 8 , wherein the plasticizer comprises one or more of triglyme, tetraglyme, and polyglyme.

10. 9. The dielectric ceramic sheet according to claim 8, wherein the molecular weight of the polyvinylpyrrolidone is 6,300 g / mol or more and 309,000 g / mol or less.

11. The dielectric ceramic sheet according to claim 8 , wherein the dispersant is disposed on the surfaces of the dielectric particles.

12. The dielectric ceramic sheet according to claim 8 , wherein nitrogen (N) elements are disposed on the surfaces of the dielectric particles.

13. 13. The dielectric ceramic sheet according to claim 8, wherein the binder comprises polyvinyl butyral.

14. 14. The dielectric ceramic sheet according to claim 13, wherein n / x satisfies a ratio of 0.67 or more to less than 3.7, where n is the number of monomers of the polyvinylpyrrolidone and x is the number of monomers of hydroxyl groups contained in the polyvinyl butyral.

Images