Multilayer ceramic electronic component precursor, and method for manufacturing multilayer ceramic electronic components

Abstract

The present invention provides: a multilayer ceramic electronic component precursor which is formed of a multilayer body wherein green sheets and internal electrode precursor layers are alternately stacked repeatedly, and which is suppressed in the occurrence of interlayer separation or breakage of the internal electrode precursor layers if this multilayer ceramic electronic component precursor is cut by the application of an external force by means of press cutting or the like; and a method for producing a multilayer ceramic electronic component, the method using this multilayer ceramic electronic component precursor.　With respect to this multilayer ceramic electronic component precursor, wherein the green sheets and the internal electrode precursor layers are alternately stacked repeatedly, an aliphatic polycarbonate resin is used as a binder resin that is contained in the green sheets; and a cellulose acylate resin having a specific structure is used as a matrix resin that is contained in the internal electrode precursor layers.

Description

[Technical Field]

[0001] The present invention relates to a multilayer ceramic electronic component precursor comprising a structure including a green sheet and an internal electrode precursor layer, and to a method for manufacturing a multilayer ceramic electronic component using the aforementioned multilayer ceramic electronic component precursor. [Background technology]

[0002] Conventionally, multilayer ceramic electronic components have been manufactured using a laminate in which a green sheet containing ceramic particles and an internal electrode precursor layer containing conductive particles are alternately stacked, as a precursor for multilayer ceramic electronic components.

[0003] Specifically, first, the multilayer ceramic electronic component precursor, which is in a state known as a mother block, is cut perpendicular to or approximately perpendicular to its plane to create smaller pieces according to the size of the multilayer ceramic electronic component to be manufactured. Then, the multilayer ceramic electronic component is manufactured by firing these small pieces of the multilayer ceramic electronic component precursor.

[0004] For example, Patent Document 1 proposes using an aliphatic polycarbonate with excellent thermal decomposition properties as a binder for dispersing ceramic particles in a sintered ceramic molding composition. Furthermore, Patent Document 2 proposes the use of ethylcellulose as a component for dispersing conductive powder, such as metal particles, in a conductive paste for forming an internal electrode layer on a dielectric layer which is a sintered ceramic in a multilayer ceramic capacitor. Ethylcellulose provides the conductive paste described in Patent Document 2 with good printing properties and excellent dispersion stability of the conductive powder. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-020916 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-168238

Summary of the Invention

Problems to be Solved by the Invention

[0006] For example, when a sheet-like layer made of a sintered ceramic molding composition as described in Patent Document 1 and a sheet-like layer made of a conductive paste as described in Patent Document 2 are laminated and combined, a laminate that provides a laminated ceramic electronic component by firing can be obtained. The sheet-like layer made of a sintered ceramic molding composition as described in Patent Document 1 corresponds to a green sheet. The sheet-like layer made of a conductive paste as described in Patent Document 2 corresponds to an internal electrode precursor layer. Such a laminate can be used as a precursor of a laminated ceramic electronic component. As described above, this precursor of a laminated ceramic electronic component is cut by a method such as die cutting according to the size of the laminated ceramic electronic component to be manufactured, and is subjected to firing in a small and divided state.

[0007] However, when an external force is applied and cut by a method such as die cutting to a laminate in which a green sheet made of a sintered ceramic molding composition as described in Patent Document 1 and an internal electrode precursor layer made of a conductive paste as described in Patent Document 2 are laminated, there are problems such as delamination between layers due to insufficient adhesion between layers and breakage in the internal electrode precursor layer.

[0008] The present invention has been made in view of the above problems, and comprises a laminate in which a green sheet and an internal electrode precursor layer are repeatedly and alternately laminated, and when cut by applying an external force by a method such as die cutting, delamination between layers and breakage of the internal electrode precursor layer are suppressed. An object is to provide a precursor of a laminated ceramic electronic component and a method for manufacturing a laminated ceramic electronic component using the precursor of the laminated ceramic electronic component.

Means for Solving the Problems

[0009] The present inventors have discovered that the above problems can be solved by using an aliphatic polycarbonate resin as the binder resin in the green sheet and a cellulose acylate resin of a specific structure as the matrix resin in the internal electrode precursor layer in a multilayer ceramic electronic component precursor in which a green sheet and an internal electrode precursor layer are repeatedly and alternately laminated, and have completed the present invention. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a multilayer ceramic electronic component precursor comprising a laminate in which a green sheet and an internal electrode precursor layer are repeatedly and alternately stacked, wherein delamination between layers and fracture of the internal electrode precursor layer are suppressed when an external force is applied and cut by a method such as a press cutter, and a method for manufacturing a multilayer ceramic electronic component using the multilayer ceramic electronic component precursor. [Modes for carrying out the invention]

[0011] <<Precursors for multilayer ceramic electronic components>> The multilayer ceramic electronic component precursor is a laminate in which a green sheet and an internal electrode precursor layer are repeatedly and alternately stacked. The green sheet contains ceramic particles and a binder. The internal electrode precursor layer comprises conductive inorganic particles and a matrix resin. The binder contains aliphatic polycarbonate resin. The matrix resin includes a cellulose acylate-based resin containing a cellulose acylate structure. Cellulose acylate resins have acyl groups selected from propionyl groups and butanoyl groups in their cellulose acylate structure.

[0012] Multilayer ceramic electronic component precursors are fired to form multilayer ceramic electronic components. The green sheet in the multilayer ceramic electronic component precursor is fired to form a dielectric layer. The internal electrode precursor is fired to form an internal electrode layer. In other words, in multilayer ceramic electronic components such as multilayer ceramic capacitors, dielectric layers and internal electrode layers are repeatedly stacked alternately. Suitable examples of multilayer ceramic electronic components include multilayer ceramic capacitors, inductors, piezoelectric elements, thermistors, and the like.

[0013] In multilayer ceramic electronic component precursors, the thickness of the laminated dielectric layer is preferably 4.0 μm or less, more preferably 1.0 μm or less, and even more preferably 0.4 μm or less. The thickness of the laminated dielectric layer is preferably 0.15 μm or more. More specifically, the thickness of the dielectric layer is preferably 0.15 μm or more and 4.0 μm or less, more preferably 0.15 μm or more and 1.0 μm or less, and even more preferably 0.15 μm or more and 0.4 μm or less. In multilayer ceramic electronic components, the total number of dielectric layers is preferably between 15 and 700. Therefore, in the multilayer ceramic electronic component precursor, the number of green sheet layers is also preferably between 15 and 700.

[0014] In the multilayer ceramic electronic component precursor, the thickness of the stacked internal electrode layer is preferably 1.5 μm or less, more preferably 0.20 μm to 1.0 μm, and even more preferably 0.20 μm to 0.80 μm. In multilayer ceramic electronic components, the total number of internal electrode layers is preferably between 15 and 700. Therefore, in multilayer ceramic electronic component precursors, the number of internal electrode precursor layers is also preferably between 15 and 700.

[0015] For example, by stacking and pressing together a large number of two-layer laminates, each having an internal electrode precursor layer, on a green sheet, a laminate suitable for use as a precursor for multilayer ceramic electronic components can be obtained. The pressing may be performed by methods such as hydrostatic pressing.

[0016] Multilayer ceramic electronic components can be manufactured by firing a multilayer ceramic electronic component precursor, which is a laminate, and then adding a configuration according to the type of multilayer ceramic electronic component to the fired laminate, or by firing the laminate to which the above-mentioned multilayer ceramic electronic component precursor has been added according to the type of multilayer ceramic electronic component. As described above, the multilayer ceramic electronic component precursor can be suitably used in the manufacture of multilayer ceramic electronic components.

[0017] The shape of the internal electrode layer in a multilayer ceramic electronic component is not particularly limited. The shape of the internal electrode layer, when observed from a direction perpendicular to the surface direction of the internal electrode layer, is preferably rectangular, but it may also be a coil shape or the like. The shape of the internal electrode precursor layer is adopted to correspond to the shape of the internal electrode layer to be formed.

[0018] Typically, multilayer ceramic electronic components are manufactured by cutting the above-mentioned multilayer ceramic electronic component precursor perpendicular or substantially perpendicular to the plane direction of the multilayer ceramic electronic component precursor using a method such as a press cutter to obtain small pieces according to the size of the multilayer ceramic electronic component to be manufactured, and then subjecting the obtained small pieces to well-known processing, including firing. Such small pieces, and laminates that have been subjected to well-known processing of such small pieces, also correspond to multilayer ceramic electronic component precursors.

[0019] When cutting multilayer ceramic electronic component precursors, shear forces applied to the cut surface can easily cause delamination and fracture of the internal electrode precursor layer. However, in the above-mentioned multilayer ceramic electronic component precursors, delamination and fracture of the internal electrode precursor layer are suppressed when cutting by applying external force using methods such as press cutting.

[0020] The following describes the green sheet and the internal electrode precursor layer that constitute the precursor of multilayer ceramic electronic components.

[0021] <Green Sheet> As mentioned above, the green sheet contains ceramic particles and a binder, which will be described later. The green sheet may also contain metal particles and other additives. As for the metal particles, metal particles as conductive inorganic particles, which will be described later for the internal electrode precursor layer, can be used. Furthermore, if the green sheet contains both ceramic particles and metal particles, the volume-based content of the ceramic particles in the green sheet is greater than that of the metal particles.

[0022] The following describes the required and optional components included in the green sheet.

[0023] 〔binder〕 The green sheet contains a binder. The binder contains aliphatic polycarbonate. To the extent that the desired effect is not impaired, the binder may contain other resins in addition to aliphatic polycarbonate. As the other resins, various resins that have been conventionally used to form green sheets can be used.

[0024] The ratio of the mass of aliphatic polycarbonate to the mass of the binder is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

[0025] The following explains aliphatic polycarbonates.

[0026] (Aliphatic polycarbonate) The aliphatic polycarbonate is not particularly limited as long as it can form a green sheet. Conventionally known aliphatic polycarbonates can be used as components of the green sheet. For example, an aliphatic polycarbonate is given by the following formula (1): -(-O-CO-O-CR 1 R 2 -CR 3 R 4 -)-···(1) Examples thereof include resins composed of structural units represented by

[0027] In formula (1), R 1 , R 2 , R 3 , and R 4 are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent. At least two of R 1 , R 2 , R 3 , and R 4 may combine to form an aliphatic ring having 3 to 10 ring-constituting atoms.

[0028] R 1 , R 2 , R 3 , and R 4 The structure of the alkyl group which may have a substituent as may be linear or branched. The number of carbon atoms of the alkyl group which may have a substituent as R 1 , R 2 , R 3 , and R 4 is preferably 1 to 4, more preferably 1 or 2. The number of carbon atoms of the substituent is not included in the number of carbon atoms of the alkyl group.

[0029] R 1 , R 2 , R 3 , and R 4 Specific examples of the alkyl group as include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, and n-decyl group.

[0030] R 1 , R 2 , R 3 , and R 4 When the alkyl group as has a substituent, the number of substituents bonded to the alkyl group is not particularly limited as long as the desired effect is not impaired. The number of substituents bonded to the alkyl group is preferably 1 or 2.

[0031] R 1 , R 2 , R 3 , and R 4 Specific examples of substituents that an alkyl group may have include hydroxyl groups, alkoxy groups, ester groups, silyl groups, sulfanyl groups, cyano groups, nitro groups, sulfo groups, formyl groups, carboxyl groups, and halogen atoms.

[0032] The number of carbon atoms in the alkoxy group as a substituent is not particularly limited, but for example, 1 to 4 is preferred, and 1 or 2 is more preferred. Preferred specific examples of alkoxy groups as substituents include methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, isobutyloxy, sec-butyloxy, and tert-butyloxy groups.

[0033] Suitable examples of halogen atoms as substituents include fluorine, chlorine, bromine, and iodine atoms.

[0034] R 1 , R 2 , R 3 , and R 4 It may contain one or more groups. For example, R 1 , R 2 , R 3 , and R 4 These may be the same group. 1 , R 2 , and R 3 These are the same group, R 4 However, R 1 , R 2 , and R 3 It may be a different group. 1 , R 3 , and R 4 These are the same group, R 2 However, R 1 , R 3 , and R 4 It may be a different group. 1 , R2 , R 3 , and R 4 However, these may be four different types of bases.

[0035] R 1 , R 2 , R 3 , and R 4 At least two of these may bond to form an aliphatic ring having 3 to 10 ring-constituting atoms. The aliphatic ring may be a saturated aliphatic ring or an unsaturated aliphatic ring. The aliphatic ring may have substituents. The number of substituents that the aliphatic ring may have is not particularly limited as long as the desired effect is not impaired. If the aliphatic ring has substituents, the number of substituents is preferably 1 or 2.

[0036] Specific examples of aliphatic rings include cyclopentane rings, cyclopentene rings, cyclohexane rings, cyclohexene rings, and cycloheptane rings.

[0037] The aliphatic ring may have substituents such as alkyl groups, alkoxy groups, acyloxy groups, alkoxycarbonyl groups, silyl groups, sulfanyl groups, cyano groups, nitro groups, sulfo groups, formyl groups, and halogen atoms. Specific examples of alkyl groups as substituents include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups. Specific examples of alkoxy groups as substituents include methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, isobutyloxy, sec-butyloxy, and tert-butyloxy groups. Specific examples of acyloxy groups as substituents include acetoxy, propionyloxy, butanoyloxy, isobutanoyloxy, and pivaloyloxy groups. Specific examples of alkoxycarbonyl groups as substituents include methoxycarbonyl groups, ethoxycarbonyl groups, and tert-butoxycarbonyl groups. Specific examples of halogen atoms as substituents include fluorine, chlorine, bromine, and iodine atoms.

[0038] Polycarbonates consisting of the constituent units represented by the above formula (1) are preferably polyethylene carbonate, polypropylene carbonate (poly(propane-1,2-diyl) carbonate), and poly(1,2-cyclohexylene) carbonate. In addition to aliphatic polycarbonates consisting of the constituent units represented by formula (1) above, polytrimethylene carbonate, polytetramethylene carbonate, polyhexamethylene carbonate, poly-2,2-dimethyltrimethylene carbonate, and poly-1,4-cyclohexanedimethylene carbonate can also be suitably used as aliphatic polycarbonates.

[0039] Among the aliphatic polycarbonates described above, polyethylene carbonate, polypropylene carbonate, poly(1,2-cyclohexylene) carbonate, polytrimethylene carbonate, polytetramethylene carbonate, and poly1,4-cyclohexanedimethylene carbonate are preferred, polypropylene carbonate and polytetramethylene carbonate are more preferred, and polypropylene carbonate is even more preferred.

[0040] Furthermore, aliphatic polycarbonates having an alicyclic skeleton, which may or may not be aliphatic polycarbonates composed of the constituent units represented by formula (1), are also preferably used. Various alicyclic groups can be cited as groups having an alicyclic skeleton in aliphatic polycarbonates. Specific examples of alicyclic groups include 1,2-cyclopentylene group, 1,3-cyclopentylene group, 1,2-cyclohexylene group, 1,3-cyclohexylene group, 1,4-cyclohexylene group, limonene-1,2-diyl group, (3R,3aR,6S,6aS)-hexahydroflu[3,2-b]furan-3,6-diyl group (a group obtained by removing two hydroxyl groups from the structure of isosorbide), and (1R,4R,5R,8R)-2,6-dioxabicyclo[3.3.0]octane-4,8-diyl group (a group obtained by removing two hydroxyl groups from the structure of isomannide).

[0041] In terms of adhesion between the green sheet and the internal electrode precursor layer, among the above alicyclic groups, the (3R,3aR,6S,6aS)-hexahydroflu[3,2-b]furan-3,6-diyl group and the (1R,4R,5R,8R)-2,6-dioxabicyclo[3.3.0]octane-4,8-diyl group are preferred, and the (3R,3aR,6S,6aS)-hexahydroflu[3,2-b]furan-3,6-diyl group is more preferred.

[0042] As described later, the internal electrode precursor layer contains a cellulose acylate resin of a specific structure. The cellulose acylate resin has a structure in which hexose rings are continuously linked. Here, the structures of the (3R,3aR,6S,6aS)-hexahydroflu[3,2-b]furan-3,6-diyl group and the (1R,4R,5R,8R)-2,6-dioxabicyclo[3.3.0]octane-4,8-diyl group are similar to the structures of the hexose ring. Therefore, aliphatic polycarbonates containing (3R,3aR,6S,6aS)-hexahydrofl[3,2-b]furan-3,6-diyl groups or (1R,4R,5R,8R)-2,6-dioxabicyclo[3.3.0]octane-4,8-diyl groups are thought to exhibit good adhesion to cellulose acylate resins contained in the internal electrode precursor layer.

[0043] Examples of aliphatic polycarbonates having an alicyclic skeleton include resins consisting solely of the constituent units represented by formula (2) below, resins consisting of the constituent units represented by formula (1) above and the constituent units represented by formula (2) below, and resins consisting of carbonate units not corresponding to formula (1) above and the constituent units represented by formula (2) below. In formula (2), X is a divalent alicyclic group. -(-O-CO-OX-)-···(2)

[0044] Suitable specific examples of the alicyclic group as X are the same as the specific examples of the alicyclic group described above.

[0045] Specific examples of aliphatic polycarbonates having an alicyclic skeleton include poly(1,2-cyclopentylene) carbonate, poly(1,3-cyclopentylene) carbonate, poly(1,2-cyclohexylene) carbonate, and poly(1,3-cyclohexylene )mosquito Examples include polycarbonates derived from carboxylates, isosorbide, and isomannide. Among these, polycarbonates derived from isosorbide and polycarbonates derived from isomannide are preferred, with polycarbonates derived from isosorbide being more preferred. Commercially available polycarbonates derived from isosorbide can also be used. Examples of commercially available isosorbide-derived polycarbonates include Durabio (manufactured by Mitsubishi Chemical Corporation) and PLANEXT (manufactured by Teijin Corporation). The content of isosorbide-derived carbonate units and isomannide-derived carbonate units in isosorbide-derived polycarbonates and isomannide-derived polycarbonates is not particularly limited. The content of isosorbide-derived carbonate units and isomannide-derived carbonate units is preferably 10 mol% to 70 mol%, and more preferably 15 mol% to 50 mol%, of the total carbonate units constituting the aliphatic polycarbonate.

[0046] Aliphatic polycarbonates may be used individually or in combination of two or more types.

[0047] Aliphatic polycarbonates may have modified terminal groups to the extent that the desired effect is not impaired. Examples of terminal group modification include modification with acid anhydrides, cyclic acid anhydrides, acid halides, and isocyanate compounds.

[0048] Furthermore, the aliphatic polycarbonate may partially contain other constituent units other than polycarbonate constituent units, such as polyether constituent units, polyester constituent units, polyamide constituent units, and polyacrylate constituent units, to the extent that the desired effect is not impaired. The content of other constituent units in the aliphatic polycarbonate is preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, and particularly preferably 1 mol% or less, relative to the total number of moles of constituent units of the aliphatic polycarbonate.

[0049] [Ceramic particles] With respect to ceramic particles, it is preferable that their constituent material includes at least one selected from the group consisting of Ba, Ti, Sr, Ca, and Zr. Preferred examples of ceramic particles include barium titanate particles, calcium titanate particles, strontium titanate particles, and lead zirconate titanate particles. As for the ceramic particles, one type may be used alone, or two or more types may be used in combination.

[0050] The ceramic particle content in the green sheet is preferably 45% to 70% by volume, and more preferably 55% to 65% by volume, relative to the sum of the volume of the binder, the volume of the ceramic particles, and the volume of the additives in the green sheet. Alternatively, the volume may be calculated by observing the cross-section of the central part of the structure and deriving it from the area of ​​each particle.

[0051] [Additives] In addition to the above components, the green sheet may contain various additives. Examples of additives include at least one selected from the group consisting of plasticizers, dispersants, and antistatic agents.

[0052] Suitable examples of plasticizers include phthalate-based plasticizers such as dimethyl phthalate, diethyl phthalate, n-dibutyl phthalate, dibutyl benzyl phthalate, and alkylbutyl benzyl phthalate; glycol-based plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, and polyethylene glycol; phosphoric acid-based plasticizers such as tricresyl phosphate, tributoxyethyl phosphate, 2-ethylhexyl diphenyl phosphate, and isodecyl diphenyl phosphate; citrate-based plasticizers such as triethyl O-acetyl citrate and tributyl O-acetyl citrate; adipic acid-based plasticizers such as dibutyl adipate and dihexyl adipate; carbonate-based plasticizers such as ethylene carbonate and propylene carbonate; and epoxy-based plasticizers such as epoxidized soybean oil and epoxidized linseed oil.

[0053] The amount of additives used is not particularly limited, as long as the desired effect is not impaired. The amount of other additives used is determined appropriately, taking into account the amounts that are typically used depending on the type of additive.

[0054] [Method for forming a green sheet] Aliphatic polycarbonates are soluble in various solvents. Therefore, a paste for forming green sheets can be prepared by mixing aliphatic polycarbonates with organic solvents, ceramic particles, and other additives as needed. The resulting paste is then formed into a sheet shape using coating methods such as the die coater sheet method or the doctor blade method, and the sheet-shaped paste is then dried to obtain a green sheet. Depending on the particle size of the ceramic particles and the viscosity of the paste, gravure printing or screen printing methods can also be applied to form the paste into a sheet.

[0055] Suitable examples of organic solvents to add to the paste include alkanols such as isopropanol; carbide-soluble solvents such as toluene, xylene, and isophorone; terpineol-based solvents such as terpineol and dihydroterpineol; ester-based solvents such as ethyl acetate, n-propyl acetate, n-butyl acetate, terpineol acetate, and dihydroterpineol acetate; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl carbitol, ethyl carbitol, butyl carbitol, and propylene glycol. Examples include glycol ether solvents such as monomethyl ether, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; glycol ester solvents such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate; carbonate solvents such as dimethyl carbonate and propylene carbonate; ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone; and nitrogen-containing polar organic solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0056] The amount of organic solvent used when preparing a paste is not particularly limited. The amount of organic solvent used is adjusted as appropriate so that the viscosity of the paste is suitable for the printing or coating method to be performed using the paste.

[0057] <Internal electrode precursor> The internal electrode precursor layer contains conductive inorganic particles and a matrix resin. The matrix resin will be described later. By including the matrix resin described later in the internal electrode precursor layer, delamination between layers and fracture of the internal electrode precursor layer are suppressed when the multilayer ceramic electronic component precursor is cut by applying external force such as by a cutting tool.

[0058] The following describes the essential and optional components contained in the internal electrode precursor layer.

[0059] [Matrix resin] The internal electrode precursor layer contains a matrix resin. The matrix resin contains a cellulose acylate-based resin that includes a cellulose acylate structure. Cellulose acylate resins have acyl groups selected from propionyl groups and butanoyl groups in their cellulose acylate structure. By including the above-mentioned cellulose acylate resin as the matrix resin in the internal electrode precursor layer, delamination between layers and fracture of the internal electrode precursor layer are suppressed when the multilayer ceramic electronic component precursor is cut by applying external force such as by pressing.

[0060] Within the limits that the desired effect is not impaired, the matrix resin may contain other resins in addition to the cellulose acylate resin. Various resins conventionally used for forming the internal electrode precursor layer can be used as the other resins.

[0061] The ratio of the mass of the cellulose acylate resin to the mass of the matrix resin is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

[0062] The following describes aliphatic cellulose acylate resins.

[0063] (Cellulose acylate resin) Cellulose acylate resins are resins that have a cellulose acylate structure. A cellulose acylate structure is a structure in which cellulose is acylated. The cellulose acylate resin may be a block copolymer having blocks having a cellulose acylate structure and other blocks, or it may be a cellulose acylate consisting only of a cellulose acylate structure. When the cellulose acylate resin is a block copolymer, the block copolymer may be a linear polymer or a branched polymer. When the cellulose acylate resin is a branched polymer, the cellulose acylate block may be a main chain or a branch chain, but it is preferable that it be a main chain.

[0064] As mentioned above, cellulose acylate resins have acyl groups selected from propionyl groups and butanoyl groups in their cellulose acylate structure. In the cellulose acylate structure, the hydrogen atoms in the hydroxyl groups contained in the glucose ring that makes up cellulose are replaced by acyl groups selected from propionyl groups and butanoyl groups. Cellulose acylate resins may have acyl groups with 5 or more carbon atoms in their cellulose acylate structure, to the extent that the desired effect is not impaired. Preferably, cellulose acylate resins do not have acyl groups with 5 or more carbon atoms in their cellulose acylate structure.

[0065] In a cellulose acylate structure, some of the hydroxyl groups in the glucose ring constituting cellulose may be unsubstituted, or substituted with acetyl groups or acyl groups having 5 or more carbon atoms. In other words, a cellulose acylate resin may have one or more groups selected from hydroxyl groups, acetyl groups, and acyl groups having 5 or more carbon atoms in its cellulose acylate structure.

[0066] In the cellulose acylate structure, the sum of the degree of substitution of the propionyl group and the degree of substitution of the butanoyl group is preferably 0.7 to 3.0, more preferably 1.0 to 2.5, and even more preferably 1.5 to 2.2. In the cellulose acylate structure, the degree of unsubstituted is preferably 0.1 to 2.0, more preferably 0.2 to 1.5, and even more preferably 0.25 to 1.0. The degree of substitution in a cellulose acylate structure is the average number of acylated hydroxyl groups contained in one acylated glucose ring. The degree of unsubstituted groups in a cellulose acylate structure is the average number of unsubstituted hydroxyl groups in a single acylated glucose ring. In the cellulose acet structure, the degree of substitution of acyl groups having 5 or more carbon atoms is preferably lower than the sum of the degree of substitution of propionyl groups and butanoyl groups. In the cellulose acet structure, the degree of substitution of acyl groups having 5 or more carbon atoms is preferably 0.5 or less, more preferably 0.3 or less, even more preferably 0.1 or less, and most preferably 0.

[0067] When a cellulose acylate resin is a linear resin consisting solely of a cellulose acylate structure, suitable examples of cellulose acylate resins include cellulose acetate propionate, cellulose acetate butanoate, cellulose propionate, and cellulose butanoate.

[0068] As mentioned above, the cellulose acylate resin may be a block copolymer. This block copolymer may be a linear polymer or a branched polymer. In terms of ease of synthesis and availability, branched polymers are preferred as cellulose acylate-based resins, which are block copolymers, consisting of a main chain made of cellulose acylate and branch chains made of other polymers. In branched polymers, aliphatic polycarbonates or aliphatic polyesters are preferred as the other polymers used for the branch chains.

[0069] The following describes branched polymers having a main chain made of cellulose acylate and branch chains made of aliphatic polycarbonate or aliphatic polyester.

[0070] • Branched polymer Branched polymers have a main chain made of cellulose acylate and branch chains made of aliphatic polycarbonate or aliphatic polyester in their molecular chain. The cellulose acylate used in the preparation of branched polymers has an acyl group selected from propionyl groups and butanoyl groups, and a hydroxyl group in its cellulose acylate structure.

[0071] The branch chains may be linear or branched. Furthermore, the branch chains may be linked to two or more main chains, bridging two or more main chains.

[0072] In branched polymers, the graft ratio, which is the ratio of the mass of the branch chains to the mass of the main chain, is not particularly limited as long as the desired effect is not impaired. The graft ratio is preferably 10% by mass or more and 400% by mass or less, and more preferably 50% by mass or more and 250% by mass or less. The grafting rate can be determined by nuclear magnetic resonance spectroscopy (NMR analysis).

[0073] The mass-average molecular weight of the branched polymer is not particularly limited. For example, the mass-average molecular weight of the branched polymer is preferably between 50,000 and 1,000,000, and more preferably between 100,000 and 600,000. When the mass-average molecular weight of the branched polymer is within this range, the branched polymer exhibits good mechanical properties such as strength, elongation, and toughness, as well as good moldability.

[0074] The following describes methods for producing main chains, branch chains, and branched polymers.

[0075] The branched polymer has a main chain made of the linear cellulose acylate described above. The branched polymer may contain two or more branched polymer molecules, each having a different type of cellulose acylate as its main chain. The mass-average molecular weight of the cellulose acylate used in the preparation of branched polymers is not particularly limited. The mass-average molecular weight of the cellulose acylate is preferably 5,000 or more, more preferably 10,000 or more, and particularly preferably 100,000 or more. The mass-average molecular weight of the cellulose acylate is preferably 1,000,000 or less, more preferably 750,000 or less, and even more preferably 500,000 or less. More specifically, the mass-average molecular weight of the cellulose acylate is preferably 5,000 to 1,000,000, more preferably 10,000 to 750,000, and particularly preferably 100,000 to 500,000.

[0076] Branched polymers have branch chains bonded to a main chain made of cellulose acylate. The branch chains are made of aliphatic polycarbonate or aliphatic polyester. The branch chains may be linear or branched. Typically, a branch chain attaches to only one main chain. However, a branch chain may attach to two or more main chains, bridging two or more main chains.

[0077] The aliphatic polycarbonates or aliphatic polyesters constituting the branch chains may be formed while bonded to the main chain, or are not particularly limited in any way that they can be bonded to the main chain. Typical examples of aliphatic polycarbonates or aliphatic polyesters that constitute the branched chains are shown in the following description of the method for producing branched polymers.

[0078] The method for producing branched polymers is not particularly limited. Typically, graft polymerization is employed. Depending on the type of branch chain, the graft polymerization method can be appropriately selected from various known methods.

[0079] As a graft polymerization method, for example, a ring-opening polymerization method can be employed. By ring-opening polymerization of cyclic carbonate compounds or cyclic ester compounds such as lactones in the presence of cellulose acylate, aliphatic polycarbonates or aliphatic polyesters are formed as graft chains on the molecular chains of cellulose acylate.

[0080] For example, propylene carbonate as a cyclic compound gives branch chains made of polypropylene carbonate. Butylene carbonate as a cyclic compound gives branch chains made of polybutylene carbonate. Cyclohexene carbonate as a cyclic compound gives branch chains made of polycyclohexene carbonate. Trimethylene carbonate as a cyclic compound gives branch chains made of polytrimethylene carbonate. 2,2-dimethyltrimethylene carbonate as a cyclic compound gives branch chains made of poly(2,2-dimethyltrimethylene carbonate).

[0081] Furthermore, ε-caprolactone as a cyclic compound gives a branch chain consisting of polycaprolactone, an aliphatic polyester. L-lactide as a cyclic compound gives the L-form polylactic acid, an aliphatic polyester, as a branch chain. D-lactide as a cyclic compound gives the D-form polylactic acid, an aliphatic polyester, as a branch chain. Meso-lactide as a cyclic compound gives the syndiotactic polylactic acid, an aliphatic polyester, as a branch chain. β-propiolactone as a cyclic compound gives the D-form poly(3-hydroxypropionic acid), an aliphatic polyester, as a branch chain. β-butyrolactone as a cyclic compound gives the poly(3-hydroxybutyric acid), an aliphatic polyester, as a branch chain. γ-butyrolactone as a cyclic compound gives the poly(4-hydroxybutyric acid), an aliphatic polyester, as a branch chain. δ-valerolactone as a cyclic compound gives the poly(3-hydroxyvaleric acid), an aliphatic polyester, as a branch chain. As a cyclic compound, p-dioxanone gives poly(p-dioxanone), an aliphatic polyester, as a branch chain.

[0082] Typically, ring-opening polymerization is carried out in the presence of a catalyst. Specific examples of catalysts that can be used in ring-opening polymerization include alkali metals such as sodium and potassium; sodium hydroxide, potassium hydroxide, triethylaluminum, aluminum triisopropoxide, n-butyllithium, titanium tetraisopropoxide, titanium tetrachloride, zirconium tetraisopropoxide, tin tetrachloride, sodium stannate, and tin octanoate. , Butyl tin dilaurate , and Examples include metal-containing catalysts such as diethylzinc; basic organic compounds such as pyridine, 4-N,N-dimethylaminopyridine, 1,5,7-triazabicyclo[4.4.0]deca-5-ene (TBD), and 1,8-diazabicyclo[5.4.0]undeca-7-ene (DBT); acid catalysts such as hydrochloric acid, acetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, diphenyl phosphate, and phenol; and N-heterocyclic carbenes such as 1,3-bis(2-propyl)-4,5-dimethylimidazole-2-ylidene and 1,3-diisopropylimidazole-2-ylidene.

[0083] When performing ring-opening polymerization using cyclic carbonates, it is also preferable to use a co-catalyst along with the catalyst. Specific examples of co-catalysts include N-cyclohexyl-N'-phenylthiourea, N,N'-bis[3,5-bis(trifluoromethyl)phenyl]thiourea, N-[3,5-bis(trifluoromethyl)phenyl]-N'-cyclohexylthiourea, and (-)-spartein.

[0084] The amount of catalyst that can be used in ring-opening polymerization is determined appropriately, taking into account the amount of catalyst used in conventionally known ring-opening polymerization reactions. Typically, the amount of catalyst used is preferably 0.001 moles or more, and more preferably 0.005 moles or more, per mole of cyclic compound. Furthermore, the amount of catalyst used is preferably 0.2 moles or less, and more preferably 0.1 mole or less, per mole of cyclic compound. More specifically, the amount of catalyst used is preferably 0.001 moles or more and 0.2 moles or less per mole of cyclic compound, and more preferably 0.005 moles or more and 0.1 moles or less. The amount of co-catalyst used is the same as the amount of catalyst used.

[0085] Ring-opening polymerization is preferably carried out in the presence of a solvent. The type of solvent is not particularly limited as long as it does not inhibit the ring-opening polymerization reaction. Suitable examples of solvents include aliphatic hydrocarbon solvents such as pentane, hexane, octane, decane, and cyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, chlorobenzene, and bromobenzene; ether solvents such as ethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, and anisole; ester solvents such as ethyl acetate, n-propyl acetate, and isopropyl acetate; and amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0086] The amount of solvent used is not particularly limited as long as the ring-opening polymerization reaction proceeds smoothly. Preferably, the amount of solvent used is 100 parts by mass or more and 1000 parts by mass or less per 100 parts by mass of the cyclic compound.

[0087] Typically, ring-opening polymerization is carried out by charging a cellulose acylate, a cyclic compound, and a catalyst, along with a co-catalyst and / or solvent as needed, into a reaction vessel, and then stirring the mixture in the reaction vessel.

[0088] The preferred reaction temperature for ring-opening polymerization varies depending on the cyclic compound, the type of catalyst, the amount of catalyst used, etc. Typically, the reaction temperature for ring-opening polymerization is preferably -80°C or higher, more preferably -40°C or higher, and even more preferably 0°C or higher. In terms of achieving both good yield and suppression of side reactions, the reaction temperature for ring-opening polymerization is preferably 250°C or lower, more preferably 200°C or lower, and even more preferably 150°C or lower. More specifically, the reaction temperature for ring-opening polymerization is preferably between -80°C and 250°C, more preferably between -40°C and 200°C, and even more preferably between 0°C and 150°C.

[0089] The reaction time for ring-opening polymerization varies depending on the type of cyclic compound, the type of catalyst, the amount of catalyst used, etc. Typically, a reaction time of 1 hour to 40 hours is preferred for ring-opening polymerization.

[0090] The amount of cyclic compound used in ring-opening polymerization is determined appropriately, taking into account the grafting rate mentioned above.

[0091] Another preferred method for producing branched polymers involves copolymerizing a cyclic ether with carbon dioxide in the presence of cellulose acylate. This copolymerization reaction produces branched chains made of aliphatic polycarbonate. Cellulose acylate is as described above.

[0092] As the cyclic ether, the corresponding cyclic ether of the aliphatic polycarbonate as a branch chain is appropriately selected. Preferred examples of cyclic ethers include ethylene oxide, propylene oxide, trimethylene oxide (oxetane), 3,3-dimethyltrimethylene oxide (3,3-dimethyloxetane), 1,2-butylene oxide, 2,3-butylene oxide, isobutylene oxide, 1-pentene oxide, 2-pentene oxide, 1-hexene oxide, 1-octen oxide, 1-dodecene oxide, cyclopentene oxide, cyclohexene oxide, vinylcyclohexane oxide, 3-phenylpropylene oxide, 3,3,3-trifluoropropylene oxide, 2-phenoxypropylene oxide, 3-naphthoxypropylene oxide, butadiene monooxide, 3-vinyloxypropylene oxide, and 3-trimethylsilyloxypropylene oxide.

[0093] Among the cyclic ethers mentioned above, ethylene oxide, propylene oxide, trimethylene oxide, and 1,2-butylene oxide are preferred due to their excellent polymerization reactivity and affinity for aliphatic polycarbonates of branched polymers, with ethylene oxide, propylene oxide, and trimethylene oxide being more preferred.

[0094] An example of aliphatic polycarbonate produced by copolymerization of cyclic ethers and carbon dioxide is shown below. Ethylene oxide yields polyethylene carbonate. Propylene oxide yields polypropylene carbonate. Trimethylene oxide yields polytrimethylene carbonate.

[0095] Co-gravity of cyclic ether and carbon dioxide The combination This process is carried out in the presence of a metal catalyst. Preferred examples of metal catalysts include zinc-based catalysts, aluminum-based catalysts, chromium-based catalysts, and cobalt-based catalysts. Among these, zinc-based catalysts and cobalt-based catalysts are preferred due to their high polymerization activity.

[0096] Suitable specific examples of zinc-based catalysts include, for example, diethylzinc-water catalysts, diethylzinc-pyrogallol catalysts, bis((2,6-diphenyl)phenoxy)zinc, N-(2,6-diisopropylphenyl)-3,5-di-tert-butylsalicyaldehyde zinc, 2-((2,6-diisopropylphenyl)amide)-4-((2,6-diisopropylphenyl)imino)-2-pentenoic acid acetate, zinc adipate, and zinc glutarate.

[0097] Suitable examples of cobalt-based catalysts include cobalt acetate-acetic acid catalysts, N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminocobalt acetate, N,N'-bis-(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminocobalt pentafluorobenzoate, N,N'-bis-(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminocobalt chloride, and N,N'-bis-(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminocobalt Examples include rutonite, N,N'-bis-(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminocobalt 2,4-dinitrophenoxide, tetraphenylporphyrin cobalt chloride, tetraphenylporphyrin cobalt acetate, N,N'-bis[2-(ethoxycarbonyl)-3-oxobutylidene]-1,2-cyclohexanediaminetocobalt chloride, and N,N'-bis[2-(ethoxycarbonyl)-3-oxobutylidene]-1,2-cyclohexanediaminetocobalt pentafluorobenzoate.

[0098] Cobalt-based catalysts are preferably used in conjunction with co-catalysts. Specific examples of co-catalysts include pyridine, 4-N,N-dimethylaminopyridine, N-methylimidazole, tetrabutylammonium chloride, tetrabutylammonium acetate, triphenylphosphine, bis(triphenylphosphoranylidene)ammonium chloride, and bis(triphenylphosphoranylidene)ammonium acetate.

[0099] The amount of catalyst used in the copolymerization of cyclic ether and carbon dioxide is determined appropriately, taking into account the amounts of catalysts conventionally known for such copolymerization reactions. Typically, the amount of catalyst used is preferably 0.001 moles or more, and more preferably 0.005 moles or more, per mole of cyclic ether. Furthermore, the amount of catalyst used is preferably 0.2 moles or less, and more preferably 0.1 mole or less, per mole of cyclic ether. More specifically, the amount of catalyst used is preferably 0.001 moles or more and 0.2 moles or less per mole of cyclic compound, and more preferably 0.005 moles or more and 0.1 moles or less. The amount of co-catalyst used is the same as the amount of catalyst used.

[0100] The copolymerization of cyclic ethers and carbon dioxide is preferably carried out in the presence of a solvent. The type of solvent is not particularly limited as long as it does not inhibit the copolymerization reaction. Suitable examples of solvents include aliphatic hydrocarbon solvents such as pentane, hexane, octane, decane, and cyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, chlorobenzene, and bromobenzene; ether solvents such as ethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, and anisole; ester solvents such as ethyl acetate, n-propyl acetate, and isopropyl acetate; and amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0101] The amount of solvent used is not particularly limited as long as the copolymerization reaction proceeds smoothly. For example, the amount of solvent used is preferably 100 parts by mass or more and 1000 parts by mass or less per 100 parts by mass of cyclic ether.

[0102] Typically, copolymerization is carried out by charging a cellulose acylate, a cyclic ether, and a catalyst, along with a co-catalyst and / or solvent as needed, into a reaction vessel, then injecting carbon dioxide into the reaction vessel under pressure, and finally stirring the mixture inside the vessel.

[0103] The amounts of cyclic ether and carbon dioxide used during copolymerization are determined appropriately, taking into account the aforementioned grafting rate. When copolymerizing, the pressure of carbon dioxide in the reaction vessel is preferably 0.1 MPa or higher, more preferably 0.2 MPa or higher, and even more preferably 0.5 MPa or higher as a gauge pressure at the reaction temperature, from the viewpoint of good reaction progress. However, from the viewpoint of not needing to use expensive pressure-resistant vessels with high pressure resistance and from the viewpoint of safety during work, the pressure of carbon dioxide in the reaction vessel is preferably 20 MPa or lower, more preferably 10 MPa or lower, and may also be 5 MPa or lower. More specifically, the pressure of carbon dioxide in the reaction vessel is preferably 0.1 MPa to 20 MPa as a gauge pressure at the reaction temperature, more preferably 0.2 MPa to 10 MPa, and may also be 0.5 MPa to 5 MPa. The copolymerization reaction may be carried out under supercritical conditions of carbon dioxide.

[0104] The preferred reaction temperature for copolymerization varies depending on the type of cyclic ether, the type of catalyst, the amount of catalyst used, etc. Typically, the copolymerization reaction temperature is preferably 0°C or higher, more preferably 20°C or higher, and even more preferably 30°C or higher. In terms of achieving both good yield and suppression of side reactions, the copolymerization reaction temperature is preferably 100°C or lower, more preferably 80°C or lower, and even more preferably 60°C or lower. More specifically, the preferred reaction temperature for copolymerization is preferably 0°C to 100°C as a gauge pressure at the reaction temperature, more preferably 20°C to 80°C, and even more preferably 30°C to 60°C.

[0105] The reaction time for copolymerization varies depending on the type of cyclic ether, the type of catalyst, the amount of catalyst used, etc. Typically, the reaction time for ring-opening polymerization is preferably between 1 hour and 40 hours.

[0106] The amount of cyclic compound used in ring-opening polymerization is determined appropriately, taking into account the grafting rate mentioned above.

[0107] When the branched chains consist of an aliphatic polyester formed by polycondensation of an aliphatic dicarboxylic acid and glycols, such as polyethylene succinate, polyethylene adipate, polybutylene succinate, and polybutylene adipate, branched polymers can also be produced by co-polycondensation of an aliphatic dicarboxylic acid and glycols, depending on the structure of the aliphatic polyester, in the presence of a cellulosic resin, according to a conventional method.

[0108] [Conductive inorganic particles] The internal electrode precursor layer contains conductive inorganic particles. Typically, metal particles are used as the conductive inorganic particles. The metal constituting the metal particles is preferably at least one selected from the group consisting of Ni, Cu, Ag, Pt, and Au. The metal particles may contain two or more types of metal particles. Alternatively, the metal particles may be particles of an alloy containing two or more types of metals.

[0109] The content of conductive inorganic particles in the internal electrode precursor layer is preferably 50% to 70% by volume relative to the sum of the volume of the matrix resin, the volume of conductive inorganic particles, the volume of ceramic particles, and the volume of additives contained in the internal electrode precursor layer. Alternatively, the volume may be calculated by observing the cross-section of the central part of the structure and deriving it from the area of ​​each particle.

[0110] [Ceramic particles] The internal electrode precursor layer may contain ceramic particles along with conductive inorganic particles. As the ceramic particles, the ceramic particles described above for the green sheet can be used. The ceramic particle content in the internal electrode precursor layer is preferably 3% to 15% by volume relative to the sum of the volume of the matrix resin, the volume of conductive inorganic particles, the volume of ceramic particles, and the volume of additives contained in the internal electrode precursor layer.

[0111] [Additives] The internal electrode precursor layer may contain various additives in addition to the above components. Examples of additives include at least one selected from the group consisting of plasticizers, dispersants, and antistatic agents. Specific examples of plasticizers are as described for the green sheet. The amount of other additives used is not particularly limited, as long as the desired effect is not impaired. The amount of other additives used is determined appropriately, taking into account the amount that is normally used depending on the type of additive.

[0112] [Method for forming the internal electrode precursor layer] The method for forming the internal electrode precursor layer is not particularly limited. The internal electrode precursor layer can be formed by a method similar to that used for the green sheet. Cellulose acylate resins are soluble in various solvents. Therefore, a paste for forming an internal electrode precursor layer can be prepared by mixing the cellulose acylate resin with an organic solvent, conductive inorganic particles, and other additives as needed. The resulting paste can be molded into a sheet shape using coating methods such as the die coater sheet method or the doctor blade method, and then the sheet-shaped paste can be dried to form the internal electrode precursor layer. Depending on the particle size of the conductive inorganic particles and the viscosity of the paste, gravure printing or screen printing methods can also be applied to form the paste into a sheet.

[0113] Suitable examples of organic solvents to be added to the paste are the same as the suitable examples of organic solvents that may be used when preparing the paste described for the green sheet.

[0114] The amount of organic solvent used when preparing a paste is not particularly limited. The amount of organic solvent used is adjusted as appropriate so that the viscosity of the paste is suitable for the printing or coating method to be performed using the paste.

[0115] ≪Manufacturing Method for Multilayer Ceramic Electronic Components≫ The ceramic electronic component precursor described above is cut perpendicular to or approximately perpendicular to the plane direction of the ceramic electronic component precursor to obtain small pieces according to the size of the multilayer ceramic electronic component to be manufactured. Multilayer ceramic electronic components are manufactured by a method that includes firing the obtained small pieces. The ceramic electronic component precursor can be cut using well-known methods such as a dicing saw. The firing conditions for the small pieces can be appropriately determined from well-known conditions depending on the composition of the green sheet and the composition of the internal electrode precursor layer.

[0116] As stated above, according to the inventors, the following <1> ~< 9 > will be provided. <1> The green sheet and the internal electrode precursor layer are repeatedly and alternately stacked. The aforementioned green sheet comprises ceramic particles and a binder. The internal electrode precursor layer comprises conductive inorganic particles and a matrix resin. The binder comprises an aliphatic polycarbonate resin, The matrix resin includes a cellulose acylate resin containing a cellulose acylate structure, The cellulose acylate resin has an acyl group selected from propionyl groups and butanoyl groups in the cellulose acylate structure, and is a precursor for multilayer ceramic electronic components. <2> The cellulose acylate resin has at least one of a hydroxyl group and an acetyl group in the cellulose acylate structure. <1> The multilayer ceramic electronic component precursor described above. <3> In the cellulose acylate structure, the sum of the degree of substitution of the propionyl group and the degree of substitution of the butanoyl group is 0.7 or more and 3.0 or less. <1> or <2> As described Lamination Ceramic electronic component precursor. <4> The degree of unsubstituted in the cellulose acylate structure is 0.25 or more and 1.0 or less. <3> The multilayer ceramic electronic component precursor described above. <5> The cellulose acylate resin does not have an acyl group with 5 or more carbon atoms in the cellulose acylate structure. <1> or <2> The multilayer ceramic electronic component precursor described above. <6> The conductive inorganic particles include metal particles made of at least one metal selected from the group consisting of Ni, Cu, Ag, Pt, and Au. <1> ~ <5> A multilayer ceramic electronic component precursor as described in any one of the following. <7> The material constituting the ceramic particles includes at least one selected from the group consisting of Ba, Ti, Sr, Ca, and Zr. <1> ~ <6> A multilayer ceramic electronic component precursor as described in any one of the following. <8> The aliphatic polycarbonate resin contains constituent units derived from isosorbide. <1> ~ <7> A multilayer ceramic electronic component precursor as described in any one of the following. <9> <1> ~ <8> The ceramic electronic component precursor described in any one of the above is cut in a direction perpendicular to or substantially perpendicular to the plane direction of the ceramic electronic component precursor to obtain small pieces according to the size of the multilayer ceramic electronic component to be manufactured. A method for manufacturing a multilayer ceramic electronic component, comprising firing the aforementioned small pieces.

[0117] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples.

[0118] [Example 1] (Preparation of dielectric paste) 7.2 parts by mass of polypropylene carbonate, an aliphatic polycarbonate (polypropylene carbonate having carboxylic acid-modified sites in its repeating structure, with a proportion of 0.8 mol% of the overall structure), was dissolved in 26 parts by mass of n-butyl acetate and 26 parts by mass of dimethyl carbonate. To the resulting solution, 40 parts by mass of barium titanate particles (BET equivalent diameter 0.2 μm) as ceramic particles, 0.7 parts by mass of polyethylene glycol as a plasticizer, and 0.1 parts by mass of an antistatic agent were added. The resulting suspension was then dispersed in a ball mill for a predetermined time to obtain a dielectric paste.

[0119] (Preparation of the green sheet) Using the obtained dielectric paste, a doctor blade method was used to form a sheet with a thickness of 1.4 μm after firing, and the formed sheet was dried to obtain a green sheet.

[0120] (Preparation of conductive paste) 49.4 parts by mass of Ni particles, 7.9 parts by mass of barium titanate particles, 2.5 parts by mass of cellulose acetate propionate, 1.0 part by mass of a dispersant, and 39.2 parts by mass of an organic solvent were uniformly mixed. The resulting mixture was dispersed using a roller to obtain a conductive paste. The degree of substitution of the propionyl group in cellulose acetate propionate was 1.75. The degree of unsubstituted cellulose acetate propionate (amount of hydroxyl groups) was 0.25. The degree of substitution of the acetyl group in cellulose acetate propionate (amount of hydroxyl groups) was 1.00.

[0121] (Adjustment of conductive sheet (internal electrode precursor layer)) A conductive paste was screen printed onto a green sheet. The printed conductive paste was dried to obtain a conductive sheet. The conductive paste was printed onto the green sheet as a pattern such that the planar dimensions of the internal electrodes in the cut and fired chip-shaped laminate were 3.2 mm × 1.6 mm. The thickness of the conductive sheet, measured by X-ray fluorescence analysis (XRF analysis) and considering only the metal component, was 0.4 μm. The thickness of the conductive sheet immediately after drying was 0.8 μm. m there were.

[0122] (Laminated) 218 green sheets, each having a conductive sheet formed by the method described above, were laminated together, and 20 green sheets without a coating film on the top and bottom layers were added on top of each other. The entire structure was then compressed to obtain a laminate containing a total of 258 green sheets.

[0123] (Cut) The resulting laminate was divided by cutting it with a dicing saw in a direction perpendicular to the surface direction of the laminate. The size of the divided laminate was adjusted so that, after firing, the size of the surface perpendicular to the thickness direction would be 1.0 mm × 0.5 mm.

[0124] In the above process, the delamination of the laminate when it was cut by pressing and the fracture of the conductive sheet (internal electrode precursor layer) were evaluated according to the following method.

[0125] <Evaluation of delamination during cut-and-sew cutting> For 100 randomly selected laminates that had been cut with a dicing saw, the cut surfaces were observed using an optical microscope to check for delamination between the green sheet and the conductive sheet (internal electrode precursor layer) at the cut surface. The number of laminates in which delamination was observed is shown in Table 1.

[0126] <Evaluation of the breakdown of the conductive sheet (internal electrode precursor layer) during cut-and-slash cutting> For 100 randomly selected laminates that had been cut with a dicing saw, the cut surface of each was observed with an optical microscope to check for the presence or absence of damage to the conductive sheet (internal electrode precursor layer) at the cut surface. Destruction of conductive sheet The number of laminates that were found to be suitable is shown in Table 1.

[0127] [Example 2] A laminate was prepared in the same manner as in Example 1, except that a cellulose acetate propionate was used in which the degree of substitution of propionyl groups was 0.70, the degree of unsubstituted groups (hydroxyl group amount) was 0.25, and the degree of substitution of acetyl groups was 2.05. The same evaluation was performed as in Example 1.

[0128] [Example 3] A laminate was prepared in the same manner as in Example 1, except that cellulose acetate propionate was replaced with cellulose acetate butanoate having a butanoyl group substitution degree of 1.75, an unsubstituted degree (hydroxyl group amount) of 0.25, and an acetyl group substitution degree of 1.00, and the same evaluation was performed as in Example 1.

[0129] [Example 4] A laminate was prepared in the same manner as in Example 3, except that a cellulose acetate butanoate was used in which the degree of substitution of butanoyl groups was 0.70, the degree of unsubstituted groups (hydroxyl group amount) was 0.25, and the degree of substitution of acetyl groups was 2.05. The same evaluation as in Example 1 was performed.

[0130] [Example 5] A laminate was prepared in the same manner as in Example 1, except that cellulose acetate propionate was replaced with cellulose butanoate, which has a degree of substitution of 2.00 butanoyl groups and a degree of unsubstituted groups (hydroxyl group content) of 1.00. The same evaluation was performed as in Example 1.

[0131] [Example 6] Replacing polypropylene carbonate with isosorbide-derived polycarbonate. This involves converting cellulose acetate propionate to cellulose acetate butanoate, which has a degree of substitution of 1.75 of butanoyl groups and an unsubstituted degree (hydroxyl group amount) of 0.25. Otherwise, the laminate was prepared in the same manner as in Example 1, and the same evaluation was performed as in Example 1. In the isosorbide-derived polycarbonate, the content of isosorbide-derived carbonate units was 25 mol%, and the content of propylene carbonate units was 75 mol%.

[0132] [Comparative Example 1] A laminate was prepared in the same manner as in Example 1, except that cellulose acetate propionate was replaced with ethyl cellulose, and the same evaluation was performed as in Example 1.

[0133] [Comparative Example 2] A laminate was prepared in the same manner as in Example 1, except that cellulose acetate propionate was replaced with a copolymer of ethyl cellulose and polypropylene carbonate, and the same evaluation was performed as in Example 1.

[0134] [Comparative Example 3] We attempted to create a laminate in the same manner as in Example 1, but by replacing cellulose acetate propionate with cellulose diacetate. As a result, cellulose diacetate did not dissolve well in organic solvents when preparing the conductive paste. Therefore, in Comparative Example 3, we did not manufacture or evaluate the laminate.

[0135] [Comparative Example 4] A laminate was prepared in the same manner as in Example 1, except that cellulose acetate propionate was replaced with cellulose acetate pentanoate, and the same evaluation was performed as in Example 1. The degree of substitution of the propionyl group in cellulose acetate pentanoate was 1.75. The degree of unsubstituted (hydroxyl group amount) in cellulose acetate pentanoate was 0.25. The degree of substitution of the acetyl group (hydroxyl group amount) in cellulose acetate pentanoate was 1.00.

[0136] [Table 1]

[0137] Table 1 shows that in the laminate of the example, a green sheet containing aliphatic polycarbonate and ceramic particles, and an internal electrode precursor layer containing a cellulose acylate resin and conductive inorganic particles are repeatedly and alternately laminated, and in the laminate of the example using a cellulose acylate resin having acyl groups selected from propionyl groups and butanoyl groups, and not having acyl groups with 5 or more carbon atoms, it can be seen that when an external force is applied and the laminate is cut by a method such as cutting, delamination between layers and fracture of the internal electrode precursor layer are suppressed. On the other hand, in comparative examples where the laminate contained a cellulose acylate resin without an acyl group selected from propionyl groups and butanoyl groups, or a cellulose resin other than a cellulose acylate resin, in the internal electrode precursor layer, delamination between layers and destruction of the internal electrode precursor layer were likely to occur when the laminate was cut by applying external force in a manner such as cutting.

Claims

1. The green sheet and the internal electrode precursor layer are repeatedly and alternately stacked. The aforementioned green sheet contains ceramic particles and a binder. The internal electrode precursor layer comprises conductive inorganic particles and a matrix resin. The binder comprises an aliphatic polycarbonate resin, The matrix resin includes a cellulose acylate resin containing a cellulose acylate structure, The ratio of the mass of the cellulose acylate resin to the mass of the matrix resin is 50% by mass or more. The cellulose acylate resin has an acyl group selected from propionyl groups and butanoyl groups in the cellulose acylate structure, and is a precursor for multilayer ceramic electronic components.

2. The multilayer ceramic electronic component precursor according to claim 1, wherein the cellulose acylate resin has at least one of a hydroxyl group and an acetyl group in the cellulose acylate structure.

3. The multilayer ceramic electronic component precursor according to claim 1, wherein the sum of the degree of substitution of the propionyl group and the degree of substitution of the butanoyl group in the cellulose acylate structure is 0.7 or more and 3.0 or less.

4. The multilayer ceramic electronic component precursor according to claim 3, wherein the degree of unsubstituted material in the cellulose acylate structure is 0.25 or more and 1.0 or less.

5. The multilayer ceramic electronic component precursor according to claim 1, wherein the cellulose acylate resin does not have an acyl group having 5 or more carbon atoms in the cellulose acylate structure.

6. The multilayer ceramic electronic component precursor according to claim 1, wherein the conductive inorganic particles include metal particles made of at least one metal selected from the group consisting of Ni, Cu, Ag, Pt, and Au.

7. The multilayer ceramic electronic component precursor according to claim 1, wherein the material constituting the ceramic particles includes at least one selected from the group consisting of Ba, Ti, Sr, Ca, and Zr.

8. The multilayer ceramic electronic component precursor according to claim 1, wherein the aliphatic polycarbonate resin contains constituent units derived from isosorbide.

9. The cellulose acylate resin has at least one of a hydroxyl group and an acetyl group in the cellulose acylate structure. In the cellulose acylate structure, the sum of the degree of substitution of the propionyl group and the degree of substitution of the butanoyl group is 0.7 or more and 3.0 or less. The degree of unsubstituted in the cellulose acylate structure is 0.25 or more and 1.0 or less. The conductive inorganic particles include metal particles made of at least one metal selected from the group consisting of Ni, Cu, Ag, Pt, and Au. The material constituting the ceramic particles includes at least one selected from the group consisting of Ba, Ti, Sr, Ca, and Zr. The multilayer ceramic electronic component precursor according to claim 1, wherein the aliphatic polycarbonate resin contains constituent units derived from isosorbide.

10. The cellulose acylate resin has at least one of a hydroxyl group and an acetyl group in the cellulose acylate structure. The cellulose acylate resin does not have an acyl group with 5 or more carbon atoms in the cellulose acylate structure. The conductive inorganic particles include metal particles made of at least one metal selected from the group consisting of Ni, Cu, Ag, Pt, and Au. The material constituting the ceramic particles includes at least one selected from the group consisting of Ba, Ti, Sr, Ca, and Zr. The multilayer ceramic electronic component precursor according to claim 1, wherein the aliphatic polycarbonate resin contains constituent units derived from isosorbide.

11. The ceramic electronic component precursor described in any one of claims 1 to 10 is cut perpendicular to or substantially perpendicular to the surface direction of the ceramic electronic component precursor to obtain small pieces of a size corresponding to the size of the multilayer ceramic electronic component to be manufactured. A method for manufacturing a multilayer ceramic electronic component, comprising firing the aforementioned small pieces.

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