Inkjet ink, printing method, and ceramic electronic component
09738806 · 2017-08-22
Assignee
Inventors
Cpc classification
C09D11/38
CHEMISTRY; METALLURGY
H01G4/248
ELECTRICITY
International classification
H01G4/248
ELECTRICITY
Abstract
An inkjet ink that contains a functional particle having a BET-equivalent particle diameter of 50 to 1000 nm, a rheology-controlling particle having a BET-equivalent particle diameter of 4 to 40 nm, and an organic vehicle. The ink has a viscosity of 1 to 50 mPa.Math.s at a shear rate of 1000 s.sup.−1. At a shear rate of 0.1 s.sup.−1, the ink has a viscosity equal to or higher than a viscosity η calculated using the following equation: η=(D).sup.2×ρ/10.sup.4/2+80 [where η is the viscosity (mPa.Math.s) at a shear rate of 0.1 s.sup.−1, D is the BET-equivalent particle diameter (nm) of the functional particle, and ρ is the specific gravity of the functional particle].
Claims
1. An inkjet ink comprising a functional particle having a BET-equivalent average particle diameter of 50 nm to 1000 nm; a rheology-controlling particle having a BET-equivalent average particle diameter of 4 nm to 40 nm; and an organic vehicle, wherein an amount of the functional particle is in a range of 3.5% by volume to 6.9% by volume of the inkjet ink, the inkjet ink has a viscosity of 1 mPa.Math.s to 50 mPa.Math.s at a shear rate of 1000 s.sup.−1 and the inkjet ink has, at a shear rate of 0.1 s.sup.−1, a viscosity equal to or higher than a viscosity η calculated using an equation: η=(D).sup.2×ρ/10.sup.4/2+80, where D is the BET-equivalent average particle diameter of the functional particle, and ρ is a specific gravity of the functional particle.
2. The inkjet ink according to claim 1, wherein the rheology-controlling particle is a ceramic material.
3. The inkjet ink according to claim 2, wherein the rheology-controlling particle is an oxide having a perovskite structure.
4. The inkjet ink according to claim 1, wherein the rheology-controlling particle is an oxide having a perovskite structure.
5. The inkjet ink according to claim 1, wherein the organic vehicle is a mixture of an organic solvent and at least one resin selected from a cellulose-based resin, an acrylic resin, and a cyclic-acetal-based resin.
6. The inkjet ink according to claim 1, wherein, when the functional particle has a volume of 100 parts by volume of the inkjet ink, an amount of addition of the rheology-controlling particle is in a range of 3.0 parts by volume to 42.4 parts by volume.
7. The inkjet ink according to claim 1, wherein the functional particle is an electroconductive particle.
8. The inkjet ink according to claim 7, wherein the electroconductive particle is at least one metal selected from the group consisting of Au, Pt, Ag, Ni, Cu, Al, and Fe or an alloy thereof.
9. The inkjet ink according to claim 1, wherein the functional particle is a ceramic particle.
10. The inkjet ink according to claim 9, wherein the BET-equivalent average particle diameter of the functional particle is in a range of 48% to 152% of a pre-firing BET-equivalent average particle diameter of a ceramic particle that is a main component contained in a ceramic layer upon which the ink jet ink is placed.
11. A printing method comprising forming a printed film of the inkjet ink according to claim 1 using an inkjet apparatus.
12. A ceramic electronic component comprising: an electrode; and a ceramic body holding the electrode, wherein the electrode comprises the inkjet ink according to claim 1.
13. The ceramic electronic component according to claim 12, wherein the functional particle is an electroconductive particle.
14. The ceramic electronic component according to claim 13, wherein the electroconductive particle is at least one metal selected from the group consisting of Au, Pt, Ag, Ni, Cu, Al, and Fe or an alloy thereof.
15. The ceramic electronic component according to claim 13, wherein the rheology-controlling particle is based on a same main component as a dielectric ceramic material of the ceramic body.
16. A ceramic electronic component comprising: a ceramic body having a plurality of stacked ceramic layers, an inner electrode along a boundary between at least two adjacent ceramic layers of the plurality of stacked ceramic layers; and a leveling layer in an area where the inner electrode is not formed in the boundary between the at least two adjacent ceramic layers of the plurality of stacked ceramic layers, wherein the leveling layer comprises the inkjet ink according to claim 1.
17. The ceramic electronic component according claim 16, wherein the functional particle is a ceramic particle.
18. The ceramic electronic component according to claim 17, wherein the ceramic particle is based on a same main component as a dielectric ceramic material of the ceramic layers.
19. The ceramic electronic component according to claim 16, wherein the BET-equivalent average particle diameter of the functional particle is in a range of 48% to 152% of a pre-firing BET-equivalent average particle diameter of a ceramic particle that is a main component contained in the ceramic layers.
20. The ceramic electronic component according to claim 16, wherein the inner electrode comprises the inkjet ink, in the inkjet ink of the leveling layer the functional particle is a ceramic particle, and in the inkjet ink of the inner electrode the functional particle is an electroconductive particle.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(3) Referring to
(4) The multilayer ceramic capacitor 1 has a ceramic body 3 having a multilayer structure formed by multiple stacked ceramic layers 2, and also has multiple first inner electrodes 4 and multiple second inner electrodes 5 individually formed along multiple boundaries between the ceramic layers 2. The ceramic layers 2 of the multilayer ceramic capacitor 1 are composed of a dielectric ceramic material. The first inner electrodes 4 and the second inner electrodes 5 face each other across the ceramic layers 2 to form capacitances and are arranged alternately in the direction of stacking.
(5) On either end surface of the ceramic body 3, a first outer electrode 6 is formed so as to be electrically connected to the first inner electrodes 4. On the other end surface, a second outer electrode 7 is formed so as to be electrically connected to the second inner electrodes 5.
(6) For the production of this multilayer ceramic capacitor 1, ceramic green sheets 10 like the one illustrated in
(7) One either main surface of the ceramic green sheet 10, an inner-electrode printed film 11 is formed that later serves as an inner electrode 4 or 5. The inner-electrode printed film 11 has a certain thickness, and this thickness causes a height gap to appear on the ceramic green sheet 10.
(8) In the area where the inner-electrode printed film 11 is not present on the main surface of the ceramic green sheet 10, a leveling printed film 12 is formed. The leveling printed film 12 later serves as a leveling layer for compensating for the aforementioned height gap resulting from the thickness of the inner-electrode printed film 11. The step of forming the leveling printed film 11 may be performed before the step of forming the inner-electrode printed film 11. Although not illustrated in
(9) The inner-electrode printed film 11 and the leveling printed film 12 are formed through inkjet printing using an ink according to this invention. Details are described in a later part.
(10) Then multiple ceramic green sheets 10 are stacked to form a green multilayer body. This green multilayer body is fired, with or without prior compression and cutting. As a result of firing, the ceramic body 3 illustrated in
(11) As mentioned above, an inkjet ink according to this invention is characterized in that the inkjet ink contains a functional particle having an average particle diameter of 50 to 1000 nm, a rheology-controlling particle having an average particle diameter of 4 to 40 nm, and an organic vehicle, and is also characterized by a viscosity of 1 to 50 mPa.Math.s at a shear rate of 1000 s.sup.−1 and a viscosity at a shear rate of 0.1 s.sup.−1 equal to or higher than a viscosity η calculated using
η=(D).sup.2×ρ/10.sup.4/2+80 Equation 1
(12) [where η is the viscosity (mPa.Math.s) at a shear rate of 0.1 s.sup.−1, D is the average particle diameter (nm) of the functional particle, and ρ is the specific gravity of the functional particle].
(13) A rheology-controlling particle having an average particle diameter of 4 to 40 nm has a very large specific surface area. Thus a large interaction works between such particles. Adding such a rheology-controlling particle to the ink leads to effective formation of a three-dimensional network structure that involves the large-diameter functional particle, which has a particle diameter of 50 nm or more, and the rheology-controlling particle. This network structure ensures that at a high shear rate the ink has low-viscosity characteristics that allow for inkjet printing (1 to 50 mPa.Math.s at a shear rate of 1000 s.sup.−1) and at a low shear rate the ink has high-viscosity characteristics that provide a sufficient inhibitory effect on the sedimentation of the functional particle having an average particle diameter of 50 to 1000 nm and an anti-bleeding effect (a viscosity at a shear rate of 0.1 s.sup.−1 equal to or higher than η calculated using Equation 1 above).
(14) For this rheology-controlling effect of the rheology-controlling particle to be enhanced, the amount of addition of the rheology-controlling particle is preferably in the range of 3.0 to 42.4 parts by volume per 100 parts by volume of the functional particle.
(15) Because of such effects, an inkjet ink according to this invention has all of three characteristics consisting of viscosity characteristics that allow for inkjet printing, sedimentation characteristics that ensure stable printing, and the nature of being unlikely to bleed after printing.
(16) The following discusses Stokes' law mentioned above again:
νs={Dp.sup.2(ρp−ρf)g}/18η
(17) (where νs is the rate of sedimentation of the particle, Dp is the diameter of the particle, ρp is the specific gravity of the particle, ρf is the specific gravity of the dispersion medium, g is the gravitational acceleration, and η is the viscosity of the dispersion medium).
(18) As mentioned above, Stokes' law indicates that in an organic ink in which a particle having a particle diameter of 50 nm or more is dispersed, increasing the viscosity η of the dispersion medium effectively reduces troublesome sedimentation of the particle.
(19) In this invention, this η is increased through the use of a three-dimensional network structure that involves a large-diameter particle having a particle diameter of 50 nm or more and a fine particle as described above. This three-dimensional network structure features its reversible formation and disintegration that occur in response to varying shear force. With decreasing diameter of the fine particle, the specific surface area increases, the number of particles per total added volume increases, and at the same time the interparticle distance becomes narrower. Thus the smaller the particle diameter of the fine particle is, the more effectively the three-dimensional network structure is formed.
(20) In more specific terms, when the ink is static or at a low shear rate, sedimentation is reduced because the formation of the three-dimensional network structure that involves a large-diameter particle and a fine particle increases η (i.e., viscosity develops at the particle interface and in a space). At a moment of inkjet printing, at which a high shear force is applied, the disintegration of the three-dimensional network structure reduces η, making it possible to apply the ink by inkjet printing. In the applied ink, furthermore, a high η achieved through the recovery of the three-dimensional network structure provides an inhibitory effect on the bleeding of dots and printed graphics.
(21) It is generally known that the use of a thixotropic agent also results in characteristics similar to the above. Thixotropic agents, however, are not suitable for inkjet printing because they trigger the formation of a three-dimensional network structure of swollen resin (development of viscosity in a space) and cause the ink to insufficiently lose its viscosity upon the disintegration of the three-dimensional network structure at a high shear force.
(22) Furthermore, thixotropy can be easily induced in an aqueous system like the one described in Patent Document 4 above because of high polarity and high surface tension, but not in an organic solvent system, which has low polarity and low surface tension. Therefore applying a design of aqueous paste like the one described in Patent Document 4, for example, to an organic solvent system would fail to induce required thixotropy.
(23) Inducing sufficient thixotropy in an organic solvent system requires at least adding a fine particle having a particle diameter of 40 nm or less as with an inkjet ink according to this invention. This is because making a particle finer increases the number of particles and accordingly shortens the inter-surface distance between particles and increases the surface area of the particle, thereby helping a three-dimensional network structure that involves the fine particle to form. This effect becomes more significant with decreasing particle diameter.
(24) In an inkjet ink according to this invention, the functional particle is made of, for example, a conductor, a resistor, a dielectric, a magnetic substance, or a phosphor. The functional particle refers to a particle made of any material that provides an electromagnetic or optical function, and can be a particle made of a mixture of multiple materials or a mixture of particles made of different materials. Whatever the concentration of the functional particle in the ink, ensuring that the viscosity at a shear rate of 0.1 s.sup.−1 is equal to or higher than η calculated using Equation 1 above provides sufficient anti-sedimentation and anti-bleeding effects.
(25) The rheology-controlling particle is defined only by its particle diameter. The rheology-controlling particle can therefore be made of any material. Preferably, the rheology-controlling particle is composed of a ceramic material (an oxide, a nitride, a boride, a silicide, or a carbide).
(26) Materials for an organic solvent and a binder that constitute the organic vehicle are not limited. Each of these constituents can be a mixture of multiple materials. As the organic solvent, for example, at least one selected from alcohol-based, ester-based, ketone-based, and ether-based solvents can be suitably used. As the binder, at least one selected from cellulose-based, acrylic, and cyclic-acetal-based binders can be suitably used.
(27) In the inkjet ink for forming the inner-electrode printed film 11 illustrated in
(28) The electroconductive particle is preferably made of at least one metal selected from the group consisting of Au, Pt, Ag, Ni, Cu, Al, and Fe or an alloy containing at least one metal selected from this group. These metals are suitable for use as materials for an electrode in a ceramic electronic component such as the multilayer ceramic capacitor 1.
(29) In the inkjet ink for forming the leveling printed film 12 illustrated in
(30) In the above case, ensuring that the average particle diameter of the functional particle is in the range of 48% to 152% of the pre-firing average particle diameter of the ceramic particle that is the main component of the ceramic layers 2 further reduces the shrinkage mismatch that occurs between the ceramic green sheets 10 and the leveling printed film 12 during firing, thereby providing an inkjet ink that has heat shrinkage characteristics that make the resulting multilayer ceramic capacitor 1 less likely to have structural defects.
(31) Although the foregoing describes a case where an inkjet ink according to this invention is for use in a multilayer ceramic capacitor 1 and is used to form both an inner-electrode printed film 11 to serve as inner electrodes 4 and 5 and a leveling printed film 12 to serve as a leveling layer, an inkjet ink according to this invention may also be used to form only one of the inner-electrode printed film 11 and the leveling printed film 12.
(32) Furthermore, the applications of an inkjet ink according to this invention are not limited to a multilayer ceramic capacitor 1 and include other multilayer ceramic electronic components and even non-multilayer ceramic electronic components. An inkjet ink according to this invention may also be used in fields other than electronic components.
(33) A typical form of inkjet that can be performed using an ink according to this invention is piezoelectric inkjet, but this is not the only possible form. An inkjet ink according to this invention can be applied to any form of inkjet printing that requires a low-viscosity ink.
(34) The following describes some experiment examples performed on the basis of this invention.
Experiment Example 1
(35) <Production of Inkjet Inks>
(36) As presented in Table 1, nickel powders having an average particle diameter (“average particle diameter” means “BET-equivalent average particle diameter”; the same applies hereinafter) of 10 nm, 50 nm, 100 nm, 500 nm, 1000 nm, and 2000 nm were provided as functional particles, and barium titanate powders having an average particle diameter of 4 nm, 10 nm, 30 nm, 40 nm, and 60 nm were provided as rheology-controlling particles.
(37) For samples 1 to 6, a mixture of 35 parts by weight of a functional particle having the average particle diameter indicated in the “Average functional particle diameter” column in Table 1, five parts by weight of a polymer-based dispersant, and 60 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate was processed in a pot mill to yield an inkjet ink.
(38) As for samples 7 to 32, a mixture of 35 parts by weight of a functional particle having the average particle diameter indicated in the “Average functional particle diameter” column in Table 1, five parts by weight of a rheology-controlling particle having the average particle diameter indicated in the “Average rheology-controlling particle diameter” column in Table 1, four parts by weight of a polymer-based dispersant, and 56 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate was processed in a pot mill to yield an inkjet ink.
(39) <Rheological Evaluation>
(40) The inkjet inks according to samples 1 to 32 thus obtained were subjected to the measurement of their viscosity after 3 seconds at a shear rate of 1000 s.sup.−1 and their viscosity after 5 seconds at a shear rate of 0.1 s.sup.−1 using an Anton-Paar cone rheometer (MCR300). The respective results are presented in the “Viscosity at 1000 s.sup.−1” and “Viscosity at 0.1 s.sup.−1” columns in Table 1.
(41) The cone used with the cone rheometer was one having a diameter of 75 mm (CP 75). The temperature condition was 25° C.±2° C.
(42) In addition, the “Viscosity according to Equation 1” column in Table 1 indicates the viscosity η calculated using Equation 1 above. The specific gravity of the nickel powders as the functional particles was assumed to be 8.9.
(43) <Evaluation of Sedimentability>
(44) The sedimentability of the obtained inkjet inks according to the individual samples was evaluated through a 4-hour continuous printing with these inks using a piezoelectric inkjet printer. If the thickness of the resulting printed film was in a margin of target thickness 1.0 μm±5%, the sample was marked “⊙” in the “Sedimentability” column in Table 1. If the thickness exceeded a margin of 1.0 μm±5% but fell within 1.0 μm±10%, the sample was marked “◯” in the “Sedimentability” column. If the thickness exceeded a margin of 1.0 μm±10% but fell within 1.0 μm±20%, the sample was marked “Δ” in the “Sedimentability” column. If the thickness exceeded a margin of 1.0 μm±20% or if the nozzle clogged during printing, the sample was marked “x” in the “Sedimentability” column.
(45) <Evaluation of Printing Bleeds>
(46) The bleeding of the obtained inkjet inks according to the individual samples was evaluated through the printing of 500 dots having an average diameter of 70 μm on a ceramic green sheet using a piezoelectric inkjet printer with these inks and the assessment of the roundness of each dot and dot diameters using NEXIV-VMR-6555 (Nikon). If the average roundness of the dots/the average dot diameter was less than 15%, the sample was marked “⊙” in the “Printing bleeds” column in Table 1. If this ratio was in the range of 15% to 20%, the sample was marked “◯” in the “Printing bleeds” column. If this ratio was not in the range of 20% or less, the sample was marked “x” in the “Printing bleeds” column.
(47) Note that the roundness is a value calculated in accordance with “JIS B 0621-1984.” If this value is 0, the dot can be deemed as a perfect circle with no bleeds.
(48) <Evaluation of Structural Defects>
(49) Through the following procedure, ceramic bodies for a multilayer ceramic capacitor were produced using the inkjet inks according to the individual samples, and the obtained ceramic bodies were evaluated for structural defects.
(50) A mixture of predetermined proportions of a barium-titanate-based ceramic material, an organic binder, an organic solvent, a plasticizer, and a dispersant was made into a ceramic slurry through wet dispersion using a ball mill.
(51) This ceramic slurry was shaped on a PET (polyethylene terephthalate) film using the doctor blade method in such a manner that its dry thickness was 6.0 μm, yielding a ceramic green sheet.
(52) Then the inkjet ink according to each sample was applied to the ceramic green sheet using a piezoelectric inkjet printer to form a printed film that should serve as an inner electrode. The printed film was formed in such a manner that its dry thickness was 1.0 μm, drawing a pattern such that the later-obtained cut and fired chips of the ceramic body had flat dimensions of 2.0 mm×1.2 mm.
(53) Then 200 ceramic green sheets having this inner-electrode printed film were removed from the PET film and stacked, and this stack was compressed in a predetermined mold.
(54) This compressed block of a multilayer body was cut into a predetermined size, yielding chips of a raw multilayer body that should serve as main components for separate multilayer ceramic capacitors.
(55) After a 10-hour degreasing in nitrogen at a temperature of 350° C., this raw multilayer body was fired through a profile in which the multilayer body was maintained in a N.sub.2/H.sub.2/H.sub.2O mixed atmosphere at a temperature of 1200° C. for 2 hours with the oxygen partial pressure at 10.sup.−6 to 10.sup.−7 MPa.
(56) The appearance of each fired main component, i.e., a ceramic body containing an inner electrode, was observed for the assessment of structural defects such as delamination and cracks. One hundred main components were produced for each sample, and if the number of components with any structural defect was one or less, the sample was marked “◯” in the “Structural defects” column in Table 1. If the number of components with any structural defect was two or more, the sample was marked “x” in the “Structural defects” column.
(57) TABLE-US-00001 TABLE 1 Average Average rheology- functional controlling Viscosity particle particle Viscosity at Viscosity at according to Sample diameter diameter 1000 s.sup.−1 0.1 s.sup.−1 Equation 1 Printing Structural No. (nm) (nm) (mPa .Math. s) (mPa .Math. s) (mPa .Math. s) Sedimentability bleeds defects 1 10 — 35 592 80 ⊙ ◯ X 2 50 — 32 267 81 Δ X X 3 100 — 29 176 84 X X X 4 500 — 26 85 191 X X X 5 1000 — 21 58 525 X X X 6 2000 — 23 43 1860 X X ◯ 7 10 4 46 1642 80 ⊙ ⊙ ◯ 8 50 4 43 1039 81 ⊙ ⊙ ◯ 9 100 4 30 962 84 ⊙ ⊙ ◯ 10 500 4 27 868 191 ⊙ ⊙ ◯ 11 1000 4 24 808 525 ⊙ ⊙ ◯ 12 2000 4 24 778 1860 X X ◯ 13 50 10 34 788 81 ⊙ ⊙ ◯ 14 100 10 30 665 84 ⊙ ⊙ ◯ 15 500 10 30 548 191 ⊙ ⊙ ◯ 16 1000 10 24 531 525 ⊙ ⊙ ◯ 17 2000 10 24 523 1860 X X ◯ 18 50 30 33 513 81 ⊙ ⊙ ◯ 19 100 30 29 378 84 ⊙ ⊙ ◯ 20 500 30 26 273 191 ⊙ ⊙ ◯ 21 1000 30 22 248 525 X X ◯ 22 2000 30 21 242 1860 X X ◯ 23 50 40 35 495 81 ◯ ◯ ◯ 24 100 40 29 365 84 ◯ ◯ ◯ 25 500 40 26 238 191 ◯ ◯ ◯ 26 1000 40 21 225 525 X X ◯ 27 2000 40 20 211 1860 X X ◯ 28 50 60 35 270 81 Δ X X 29 100 60 31 197 84 X X ◯ 30 500 60 23 125 191 X X ◯ 31 1000 60 21 106 525 X X ◯ 32 2000 60 20 95 1860 X X ◯
(58) Referring to the “Viscosity at 1000 s.sup.−1” column in Table 1, all samples fell within the viscosity range of 1 to 50 mPa.Math.s. This indicates that all samples fell within a viscosity range where the ink could be applied using an ordinary inkjet apparatus.
(59) Next, “sedimentability” is discussed.
(60) Focusing on samples 1 to 6, which contained no rheology-controlling particle, the “sedimentability” was “x” or “Δ” for samples 2 to 6, which had an “average functional particle diameter” of 50 nm or more.
(61) Turning to samples 7 to 32, which contained a rheology-controlling particle, samples 7 to 11, 13 to 16, 18 to 20, and 23 to 25 had a “viscosity at 0.1 s.sup.−1” higher than the “viscosity according to Equation 1” and an “average rheology-controlling particle diameter” of 4 to 40 nm. The “sedimentability” of these samples, i.e., samples 7 to 11, 13 to 16, 18 to 20, and 23 to 25, was “◯” or “⊙.” Focusing on these samples, i.e., samples 7 to 11, 13 to 16, 18 to 20, and 23 to 25, the “sedimentability” of samples 7 to 11, 13 to 16, and 18 to 20 in particular, which had an “average rheology-controlling particle diameter” of 30 nm or less, was “⊙.”
(62) On the other hand, the “sedimentability” of samples 28 and 29, which had a “viscosity at 0.1 s.sup.−1” higher than the “viscosity according to Equation 1” but had an “average rheology-controlling particle diameter” of 60 nm, was “Δ” or “x.”
(63) Next, “printing bleeds” is discussed.
(64) Focusing on samples 1 to 6, which contained no rheology-controlling particle, the “printing bleeds” was “x” for samples 2 to 6, which had an “average functional particle diameter” of 50 nm or more.
(65) Turning to samples 7 to 32, which contained a rheology-controlling particle, the “printing bleeds” was “◯” or “⊙” for samples 7 to 11, 13 to 16, 18 to 20, and 23 to 25, which had a “viscosity at 0.1 s.sup.−1” higher than the “viscosity according to Equation 1” and an “average rheology-controlling particle diameter” of 4 to 40 nm. Focusing on these samples, i.e., samples 7 to 11, 13 to 16, 18 to 20, and 23 to 25, the “printing bleeds” of samples 7 to 11, 13 to 16, and 18 to 20 in particular, which had an “average rheology-controlling particle diameter” of 30 nm or less, was “⊙.”
(66) On the other hand, the “printing bleeds” of samples 28 and 29, which had a “viscosity at 0.1 s.sup.−1” higher than the “viscosity according to Equation 1” but had an “average rheology-controlling particle diameter” of 60 nm, was “x.”
(67) As can be seen from these results of the evaluation of “sedimentability” and “printing bleeds,” the anti-sedimentation and anti-bleeding effects become more significant with decreasing “average rheology-controlling particle diameter,” and effective inhibition of sedimentation and printing bleeds require that the “average rheology-controlling particle diameter” be 40 nm or less, preferably 30 nm or less.
(68) Next, “structural defects” is discussed.
(69) Focusing on samples 1 to 6, which contained no rheology-controlling particle, the “structural defects” was “x” for samples 1 to 5, which had an “average functional particle diameter of 1000 nm or less. This appears to be because the heat shrinkage temperature decreased with decreasing diameter of the functional particle.
(70) Turning to samples 7 to 32, which contained a rheology-controlling particle, the “structural defects” was “x” only for sample 28, which had a relatively large “average rheology-controlling particle diameter” of 60 nm and an extremely small “average functional particle diameter” of 50 nm. As for the other samples, i.e., samples 7 to 27 and 29 to 32, which met the condition stipulating that the “average rheology-controlling particle diameter” had to be smaller than the “average functional particle diameter,” the “structural defects” was “◯.”
(71) This indicates that when a functional particle having an “average functional particle diameter” of 50 nm or more is used, adding a rheology-controlling particle having an average diameter smaller than that of this functional particle is effective in reducing structural defects occurring in the multilayer ceramic electronic component.
(72) Then the inks according to samples 8, 10, 14, 15, 19, 20, and 25 were made into dry coatings, and their surface was observed using FE-SEM (JSM-7000F, JEOL Ltd.), identifying a morphology in which rheology-controlling particles (barium titanate particles) were evenly held near the surface of a functional particle (a Ni particle). This morphology of the coating surface suggests that in the ink, rheology-controlling particles are uniformly arranged near a functional particle. This appears to be the reason for the high anti-sedimentation, anti-bleeding, and anti-sintering effects.
Experiment Example 2
(73) <Production of Inkjet Inks>
(74) The inkjet ink according to sample 4, produced in Experiment Example 1, was provided.
(75) As presented in Table 2, a nickel powder having an average particle diameter of 500 nm was provided as a functional particle, and barium titanate particles having an average particle diameter of 4 nm and 30 nm were provided as rheology-controlling particles.
(76) For samples 33 to 38, a mixture of 35 parts by weight of the functional particle, 0.8 to 10.0 parts by weight of a rheology-controlling particle, 5 parts by weight of a polymer-based dispersant, and 50.0 to 56.2 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate was processed in a pot mill to yield an inkjet ink. As presented in the “Rheology-controlling particle/functional particle volume ratio” column in Table 2, the composition of these samples, i.e., samples 33 to 38, was one ensuring that the rheology-controlling particle corresponded to 3.0 to 42.4 parts by volume of per 100 parts by volume of the functional particle.
(77) <Rheological Evaluation>
(78) The “viscosity at 1000 s.sup.−1” and “viscosity at 0.1 s.sup.−1” in Table 2 were determined in the same way as in Experiment Example 1. The “viscosity according to Equation 1” was also calculated.
(79) <Evaluation of Sedimentability>
(80) The “sedimentability” in Table 2 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(81) <Evaluation of Printing Bleeds>
(82) The “printing bleeds” in Table 2 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(83) <Evaluation of Structural Defects>
(84) The “structural defects” in Table 2 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(85) TABLE-US-00002 TABLE 2 Average Average rheology- Rheology- functional controlling controlling Viscosity particle particle particle/functional Viscosity Viscosity according to Sample diameter diameter particle at 1000 s.sup.−1 at 0.1 s.sup.−1 Equation 1 Printing Structural No. (nm) (nm) volume ratio (mPa .Math. s) (mPa .Math. s) (mPa .Math. s) Sedimentability bleeds defects 4 500 — 0/100 26 85 191 X X X 33 500 4 3/100 25 441 191 ⊙ ⊙ ◯ 34 500 4 14.8/100 24 751 191 ⊙ ⊙ ◯ 35 500 4 42.4/100 23 1274 191 ⊙ ⊙ ◯ 36 500 30 3/100 22 207 191 ⊙ ⊙ ◯ 37 500 30 14.8/100 28 294 191 ⊙ ⊙ ◯ 38 500 30 42.4/100 26 478 191 ⊙ ⊙ ◯
(86) Referring to Table 2, “sedimentability” and “printing bleeds” are discussed.
(87) Samples 33 to 38, containing a rheology-controlling particle, had a “viscosity at 0.1 s.sup.−1” higher than the “viscosity according to Equation 1” and an “average rheology-controlling particle diameter” of 30 nm or less. The “sedimentability” and “printing bleeds” of these samples, i.e., samples 33 to 38, were “⊙.”
(88) On the other hand, as mentioned above, the “sedimentability” and “printing bleeds” were “x” for sample 4, which contained no rheology-controlling particle.
(89) Next, “structural defects” is discussed.
(90) As mentioned above, the “structural defects” of sample 4, which contained no rheology-controlling particle, was “x.”
(91) On the other hand, the “structural defects” of samples 33 to 38, which contained a rheology-controlling particle and had a “rheology-controlling particle/functional particle diameter volume ratio” in the range of 3.0/100 to 42.4/100, was “◯.”
(92) This indicates that an excellent inhibitory effect on structural defects is obtained when the “rheology-controlling particle/functional particle volume ratio” at least falls within the range of 3.0/100 to 42.4/100. Making the “rheology-controlling particle/functional particle volume ratio” more than 42.4/100 does not spoil the inhibitory effect on structural defects, but is not preferred because this leads to too small an effective area for use as an inner electrode.
Experiment Example 3
(93) <Production of Inkjet Inks>
(94) In Experiment Example 3, inkjet inks were produced whose functional particles were electroconductive particles composed of different metal species as presented in the “Functional particle” column in Table 3. The following describes how the inkjet ink according to each sample in Table 3 was produced.
(95) The inkjet ink according to sample 39 was obtained through pot-mill processing of a mixture of 40 parts by weight of a functional particle that was a Ni powder having an average particle diameter of 500 nm, 4 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 5 parts by weight of a polymer-based dispersant, and 51 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate.
(96) The inkjet ink according to sample 40 was obtained through pot-mill processing of a mixture of 40 parts by weight of a functional particle that was a Cu powder having an average particle diameter of 500 nm, 4 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 5 parts by weight of a polymer-based dispersant, and 51 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate.
(97) The inkjet ink according to sample 41 was obtained through pot-mill processing of a mixture of 44 parts by weight of a functional particle that was a Ag powder having an average particle diameter of 500 nm, 3.7 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 4.7 parts by weight of a polymer-based dispersant, and 46.6 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate.
(98) The inkjet ink according to sample 42 was obtained through pot-mill processing of a mixture of 59 parts by weight of a functional particle that was a Au powder having an average particle diameter of 500 nm, 2.7 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 3.3 parts by weight of a polymer-based dispersant, and 35 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate.
(99) The inkjet ink according to sample 43 was obtained through pot-mill processing of a mixture of 62 parts by weight of a functional particle that was a Pt powder having an average particle diameter of 500 nm, 2.6 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 3.2 parts by weight of a polymer-based dispersant, and 32 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate.
(100) The inkjet ink according to sample 44 was obtained through pot-mill processing of a mixture of 17 parts by weight of a functional particle that was an Al powder having an average particle diameter of 500 nm, 5.5 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 6.9 parts by weight of a polymer-based dispersant, and 69.3 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate.
(101) The inkjet ink according to sample 45 was obtained through pot-mill processing of a mixture of 37 parts by weight of a functional particle that was an Fe powder having an average particle diameter of 500 nm, 4.2 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 5.2 parts by weight of a polymer-based dispersant, and 52.4 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate.
(102) The composition of these samples, i.e., samples 39 to 45, was one ensuring that the “rheology-controlling particle/functional particle volume ratio” corresponded to 11/100.
(103) <Rheological Evaluation>
(104) The “viscosity at 1000 s.sup.−1” and “viscosity at 0.1 s.sup.−1” in Table 3 were determined in the same way as in Experiment Example 1. The “viscosity according to Equation 1” was also calculated.
(105) In the calculations of the “viscosity according to Equation 1” in Table 1, as mentioned above, the specific gravity of the functional particle was assumed to be 8.9 for the Ni powder. The specific gravity was assumed to be 8.9 for the Cu powder, 10.5 for the Ag powder, 19.3 for the Au powder, 21.5 for the Pt powder, 2.7 for the Al powder, and 7.9 for the Fe powder.
(106) <Evaluation of Sedimentability>
(107) The “sedimentability” in Table 3 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(108) <Evaluation of Printing Bleeds>
(109) The “printing bleeds” in Table 3 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(110) <Evaluation of Structural Defects>
(111) The “structural defects” in Table 3 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(112) TABLE-US-00003 TABLE 3 Average Average rheology- Viscosity functional controlling according particle particle Viscosity Viscosity to Sample Functional diameter diameter at 1000 s.sup.−1 at 0.1 s.sup.−1 Equation 1 Printing Structural No. paricle (nm) (nm) (mPa .Math. s) (mPa .Math. s) (mPa .Math. s) Sedimentability bleeds defects 39 Ni 500 10 23 738 223 ⊙ ⊙ ◯ 40 Cu 500 10 20 658 223 ⊙ ⊙ ◯ 41 Ag 500 10 30 527 263 ⊙ ⊙ ◯ 42 Au 500 10 20 511 483 ◯ ◯ ◯ 43 Pt 500 10 28 629 536 ◯ ◯ ◯ 44 Al 500 10 22 502 68 ⊙ ⊙ ◯ 45 Fe 500 10 24 594 198 ⊙ ⊙ ◯
(113) Referring to Table 3, “sedimentability” and “printing bleeds” are discussed.
(114) Samples 39 to 45 had a “viscosity at 0.1 s.sup.−1” higher than the “viscosity according to Equation 1” and an “average rheology-controlling particle diameter” of 10 nm. The “sedimentability” and “printing bleeds” of these samples, i.e., samples 39 to 45, were “◯” or “⊙.”
(115) These results and the results of Experiment Example 1 indicate that whatever the specific gravity of the functional particle, sufficient anti-sedimentation and anti-bleeding effects are obtained when the “viscosity at 0.1 s.sup.−1” is higher than the “viscosity according to Equation 1” and at the same time the “average rheology-controlling particle diameter” is 40 nm or less.
(116) Next, “structural defects” is discussed.
(117) The “structural defects” of samples 39 to 45, which had a “rheology-controlling particle/functional particle volume ratio” of 11/100 as mentioned above, was “◯.”
(118) These results and the results of Experiment Example 2 indicate that whatever the specific gravity of the functional particle, an excellent inhibitory effect on structural defects is obtained when the “rheology-controlling particle/functional particle volume ratio” at least falls within the range of 3.0/100 to 42.4/100.
Experiment Example 4
(119) <Production of Inkjet Inks>
(120) In Experiment Example 4, inkjet inks were produced whose organic vehicles contained different binder resins as presented in the “Binder” column in Table 4. The following describes how the inkjet ink according to each sample in Table 4 was produced.
(121) The inkjet ink according to sample 46 was obtained through pot-mill processing of a mixture of 25 parts by weight of a functional particle that was a nickel powder having an average particle diameter of 300 nm, 4 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 5 parts by weight of a polymer-based dispersant, and 66 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate.
(122) The inkjet ink according to sample 47 was obtained through pot-mill processing of a mixture of 25 parts by weight of a functional particle that was a nickel powder having an average particle diameter of 300 nm, 4 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 5 parts by weight of a polymer-based dispersant, and 66 parts by weight of an organic vehicle composed of acrylic resin and dihydro-terpineol acetate. The acrylic resin contained ethyl methacrylate, t-butyl methacrylate, and acrylic acid as monomer units.
(123) The inkjet ink according to sample 48 was obtained through pot-mill processing of a mixture of 25 parts by weight of a functional particle that was a nickel powder having an average particle diameter of 300 nm, 4 parts by weight of a rheology-controlling particle that was a barium titanate powder having an average particle diameter of 10 nm, 5 parts by weight of a polymer-based dispersant, and 66 parts by weight of an organic vehicle composed of polyvinyl butyral resin (a cyclic-acetal-based resin) and dihydro-terpineol acetate.
(124) The composition of these samples, i.e., samples 46 to 48, was one ensuring that the “rheology-controlling particle/functional particle volume ratio” corresponded to 11/100.
(125) <Rheological Evaluation>
(126) The “viscosity at 1000 s.sup.−1” and “viscosity at 0.1 s.sup.−1” in Table 4 were determined in the same way as in Experiment Example 1. The “viscosity according to Equation 1” was also calculated.
(127) <Evaluation of Sedimentability>
(128) The “sedimentability” in Table 4 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(129) <Evaluation of Printing Bleeds>
(130) The “printing bleeds” in Table 4 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(131) <Evaluation of Structural Defects>
(132) The “structural defects” in Table 4 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(133) TABLE-US-00004 TABLE 4 Average Average rheology- functional controlling Viscosity particle particle Viscosity Viscosity according to Sample diameter diameter at 1000 s.sup.−1 at 0.1 s.sup.−1 Equation 1 Printing Structural No. Binder (nm) (nm) (mPa .Math. s) (mPa .Math. s) (mPa .Math. s) Sedimentability bleeds defects 46 Ethyl 300 15 16 211 120 ⊙ ⊙ ◯ cellulose resin 47 Acrylic 300 15 13 168 120 ⊙ ⊙ ◯ resin 48 Polyvinyl 300 15 19 207 120 ⊙ ⊙ ◯ butyral resin
(134) Referring to Table 4, “sedimentability” and “printing bleeds” are discussed.
(135) Samples 46 to 48 had a “viscosity at 0.1 s.sup.−1” higher than the “viscosity according to Equation 1” and an “average rheology-controlling particle diameter” of 15 nm. The “sedimentability” and “printing bleeds” of these samples, i.e., samples 46 to 48, were “⊙.”
(136) These results and the results of Experiment Example 1 indicate that with any kind of binder resin, sufficient anti-sedimentation and anti-bleeding effects are obtained when the “viscosity at 0.1 s.sup.−1” is higher than the “viscosity according to Equation 1” and at the same time the “average rheology-controlling particle diameter” is 40 nm or less. In addition to this, these effects are satisfactorily obtained even with a mixture of multiple binder resins, rather than a single binder resin.
(137) Next, “structural defects” is discussed.
(138) The “structural defects” of samples 46 to 48, which had a “rheology-controlling particle/functional particle volume ratio” of 11/100 as mentioned above, was “◯.”
(139) These results and the results of Experiment Example 2 indicate that with any kind of binder resin, an excellent inhibitory effect on structural defects is obtained when the “rheology-controlling particle/functional particle volume ratio” at least falls within the range of 3.0/100 to 42.4/100. In addition to this, this effect is satisfactorily obtained even with a mixture of multiple binder resins, rather than a single binder resin.
Experiment Example 5
(140) <Production of Inkjet Inks>
(141) As presented in Table 5, barium titanate powders having an average particle diameter of 10 nm, 50 nm, 100 nm, 250 nm, 400 nm, and 500 nm were provided as functional particles, and a barium titanate powder having an average particle diameter of 10 nm was provided as a rheology-controlling particle.
(142) For samples 49 to 54, a mixture of 26 parts by weight of a functional particle having the average particle diameter indicated in the “Average functional particle diameter” column in Table 5, five parts by weight of a polymer-based dispersant, and 69 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate was processed in a high-pressure homogenizer to yield an inkjet ink.
(143) Turning to samples 55 to 60, a mixture of 25 parts by weight of a functional particle having the average particle diameter indicated in the “Average functional particle diameter” column in Table 5, four parts by weight of a rheology-controlling particle having the average particle diameter indicated in the “Average rheology-controlling particle diameter” column in Table 5, five parts by weight of a polymer-based dispersant, and 60 parts by weight of an organic vehicle composed of ethyl cellulose resin and dihydro-terpineol acetate was processed in a high-pressure homogenizer to yield an inkjet ink.
(144) <Rheological Evaluation>
(145) The “viscosity at 1000 s.sup.−1” and “viscosity at 0.1 s.sup.−1” in Table 5 were determined in the same way as in Experiment Example 1. The “viscosity according to Equation 1” was also calculated.
(146) In the calculations of the “viscosity according to Equation 1” in Table 5, the specific gravity of the barium titanate particle used as the functional particle was assumed to be 6.0.
(147) <Evaluation of Sedimentability>
(148) The “sedimentability” in Table 5 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(149) <Evaluation of Printing Bleeds>
(150) The “printing bleeds” in Table 5 was evaluated in the same way as in Experiment Example 1 and presented in the same way.
(151) <Evaluation of Structural Defects>
(152) For the evaluation of the “structural defects” in Table 5, sample ceramic bodies for a multilayer ceramic capacitor were produced in the same way as in Experiment Example 1, except for some differences in the production method.
(153) A mixture of predetermined proportions of a barium-titanate-based ceramic material, an organic binder, an organic solvent, a plasticizer, and a dispersant was made into a ceramic slurry through wet dispersion using a high-pressure homogenizer similar to the one used to produce the inkjet inks.
(154) A dried and degreased powder of this ceramic slurry had a BET-equivalent diameter of approximately 250 nm.
(155) This ceramic slurry was shaped on a PET (polyethylene terephthalate) film using the doctor blade method in such a manner that its dry thickness was 6.0 μm, yielding a ceramic green sheet.
(156) Then a Ni paste was applied to the ceramic green sheet using a screen printer to form a Ni coating that should serve as an inner electrode. The Ni coating was formed in such a manner that its dry physical thickness was 1.0 μm, drawing a pattern such that the later-obtained cut and fired chips of the ceramic body had flat dimensions of 2.0 mm×1.2 mm. Then the inkjet ink according to each sample was applied to all the area on the ceramic green sheet not occupied by the Ni coating using a piezoelectric inkjet printer to form a leveling inkjet-printed film. The printed film was formed in such a manner that its dry physical thickness was 1.0 μm.
(157) Then 200 ceramic green sheets having the inner-electrode Ni coating and the leveling inkjet-printed film were removed from the PET film and stacked, and this stack was compressed in a predetermined mold.
(158) This compressed block of a multilayer body was cut into a predetermined size, yielding chips of a raw multilayer body that should serve as main components for separate multilayer ceramic capacitors.
(159) After a 10-hour degreasing in nitrogen at a temperature of 350° C., this raw multilayer body was fired through a profile in which the multilayer body was maintained in a N.sub.2/H.sub.2/H.sub.2O mixed atmosphere at a temperature of 1200° C. for 2 hours with the oxygen partial pressure at 10.sup.−6 to 10.sup.−7 MPa.
(160) As in Experiment Example 1, the appearance of each fired main component, i.e., a ceramic body containing an inner electrode, was observed for the assessment of structural defects such as delamination and cracks. One hundred main components were produced for each sample, and if the number of components with any structural defect was one or less, the sample was marked “◯” in the “Structural defects” column in Table 5. If the number of components with any structural defect was two or more, the sample was marked “x” in the “Structural defects” column.
(161) TABLE-US-00005 TABLE 5 Functional particle Average diameter/ Average rheology- ceramic functional controlling green sheet Viscosity particle particle particle Viscosity Viscosity according to Sample diameter diameter diameter at 1000 s.sup.−1 at 0.1 s.sup.−1 Equation 1 Printing Structural No. (nm) (nm) (%) (mPa .Math. s) (mPa .Math. s) (mPa .Math. s) Sedimentability bleeds defects 49 10 — 4 35 1026 80 ⊙ ◯ X 50 50 — 20 31 359 81 Δ X X 51 100 — 48 31 318 84 Δ X ◯ 52 250 — 100 26 195 99 Δ X ◯ 53 400 — 152 20 158 123 X X ◯ 54 500 — 200 22 147 155 X X X 55 10 10 4 36 1382 80 ⊙ ◯ X 56 50 10 20 34 587 81 ⊙ ⊙ X 57 100 10 48 30 419 84 ⊙ ⊙ ◯ 58 250 10 100 28 317 99 ⊙ ⊙ ◯ 59 400 10 152 24 292 123 ⊙ ⊙ ◯ 60 500 10 200 24 284 155 ⊙ ⊙ X
(162) Referring to Table 5, “sedimentability” and “printing bleeds” are discussed.
(163) Focusing on samples 49 to 54, which contained no rheology-controlling particle, the “sedimentability” was “x” or “Δ” and the “printing bleeds” was “x” for samples 50 to 54, which had an “average functional particle diameter” of 50 nm or more.
(164) Turning to samples 55 to 60, which contained a rheology-controlling particle, samples 56 to 60, which had an “average functional particle diameter” of 50 nm or more, had a “viscosity at 0.1 s.sup.−1” higher than the “viscosity according to Equation 1” and an “average rheology-controlling particle diameter” of 10 nm. The “sedimentability” and “printing bleeds” of these samples, i.e., samples 56 to 60, were “⊙.”
(165) These results and the results of Experiment Example 1 indicate that even with a ceramic (barium titanate) functional particle, sufficient anti-sedimentation and anti-bleeding effects are obtained when the “average functional particle diameter” is 50 nm or more, the “viscosity at 0.1 s.sup.−1” is higher than the “viscosity according to Equation 1,” and at the same time the “average rheology-controlling particle diameter” is 40 nm or less.
(166) Next, “structural defects” is discussed.
(167) The “functional particle diameter/ceramic green sheet particle diameter” in Table 5 represents a ratio [%] of the “average functional particle diameter” to the average particle diameter of the ceramic particle that was the main component of the ceramic green sheet mentioned above. The average particle diameter of the ceramic particle that was the main component of the above ceramic green sheet was assumed to be 250 nm.
(168) For samples 51 to 53 and 57 to 59, which had a “functional particle diameter/ceramic green sheet particle diameter” of 48% to 152%, the “structural defects” was “◯” whether a rheology-controlling particle was added or not. This indicates that when forming a leveling ceramic printed film in a multilayer ceramic electronic component, one can reduce the shrinkage mismatch that occurs during firing and thus obtain a multilayer ceramic electronic component without structural defects by ensuring that the average particle diameter of the ceramic powder contained in the leveling printed film as a functional particle is in the range of 48% to 152% of the pre-firing average particle diameter of the ceramic particle that is the main component of the ceramic layers of the multilayer ceramic electronic component.
(169) Samples 51 to 53, containing no rheology-controlling particle, were graded “◯” for “structural defects” but “x” or “Δ” for “sedimentability” and “x” for “printing bleeds,” failing to meet all of three points consisting of reduced sedimentation, reduced printing bleeds, and reduced structural defects. On the other hand, samples 57 to 59, which contained a rheology-controlling particle, met all of three points consisting of reduced sedimentation, reduced printing bleeds, and reduced structural defects.
(170) When using a ceramic powder having an average particle diameter of 50 nm or more as a functional particle in an inkjet ink for forming a leveling printed film for a multilayer ceramic electronic component, therefore, one can obtain an inkjet ink that has all of desired anti-sedimentation, anti-bleeding, and heat shrinkage characteristics by adding a rheology-controlling particle having an average particle diameter of 40 nm or less.
REFERENCE SIGNS LIST
(171) 1 Multilayer ceramic capacitor
(172) 2 Ceramic layer
(173) 3 Ceramic body
(174) 4, 5 Inner electrodes
(175) 10 Ceramic green sheet
(176) 11 Inner-electrode printed film
(177) 12 Leveling printed film