Ceramic molding binder composition and slurry composition

Abstract

This invention provides a binder composition for ceramic molding, comprising 15-95% by mass of component (A) and 5-85% by mass of component (B). Component (A) is a copolymer comprising 70-99 mol% of structural units from formula (1), 1-30 mol% of structural units from formula (2), and 0-29 mol% of other structural units, and having a weight-average molecular weight of 50,000-1,000,000. Formula (1) CH2=CR 1 -COO-R 2 In equation (1), R 1 R represents a hydrogen atom or a methyl group. 2 Representing alkyl groups with 1 to 8 carbon atoms, formula (2) CH2=CR 3 -COO-R 4 In equation (2), R 3 R represents a hydrogen atom or a methyl group. 4 Represents a hydroxyalkyl group having 1 to 8 carbon atoms and 1 to 2 hydroxyl groups; Component (B): The compound represented by formula (3), formula (3)R 5 O-(EO) p -(PO) q In equation (3), R 5 It is an alkyl group with 9 carbon atoms, EO is vinyl oxide, PO is propylene oxide, p is the average number of moles of EO added and p = 3 to 9, q is the average number of moles of PO added and q = 2 to 4, and p / q = 1.0 to 3.0.

Description

Technical Field

[0001] The present invention relates to a binder composition for ceramic molding and a slurry composition containing the binder composition. Background Technology

[0002] In the field of information electronics, various electronic components are utilized, such as multilayer ceramic capacitors (hereinafter sometimes referred to as "MLCCs"). MLCCs have a structure formed by alternately stacking dielectric layers made of ceramic powder and electrode layers made of conductive materials. The dielectric layer is manufactured, for example, by the following method: First, ceramic powder, solvent, and binder are mixed to prepare a ceramic slurry. The ceramic slurry is then uniformly coated onto a support using a doctor blade or the like, and then dried. The resulting ceramic green sheet (hereinafter sometimes referred to as "green sheet") is then fired, thereby forming the dielectric layer.

[0003] As a binder used to form green sheets, polyvinyl butyral (hereinafter sometimes referred to as "PVB"), which has excellent general strength and elongation, is used, for example, as described in Patent Document 1. However, in the process of removing the binder by decomposition through heat treatment (hereinafter sometimes referred to as "degreasing"), there are cases where the degreasing is poor, residue is generated on the green sheet, and the performance of MLCCs deteriorates. Therefore, as a binder with good degreasing properties, acrylic resins, for example, as described in Patent Document 2, are useful.

[0004] On the other hand, while using PVB or acrylic resins as binders can impart strength to the green sheet, it lacks elongation and sometimes causes cracking. In such cases, it is effective to use a plasticizer simultaneously to impart softness to the green sheet. As a plasticizer, for example, as described in Patent Document 3, aromatic carboxylic acid esters, polyalkylene glycol plasticizers, vegetable oil compounds, etc., can be used.

[0005] In recent years, the production of thinner and multilayered green wafers has been continuously developing. To address this trend, ceramic slurries containing acrylic resins as binders and polyalkylene glycol compounds as plasticizers have been developed as a means to obtain green wafers with excellent smoothness and strength, based on ease of molecular design. These ceramic slurries are known to exhibit high degreasing properties even during relatively low-temperature heat treatments at 400°C. However, the thermal decomposition removal based on the degreasing process is insufficient due to the structure of the green wafer, resulting in the formation of small residues. Particularly in the temperature range of approximately 300°C to 400°C, the rapid thermal decomposition of gases can cause fine voids and impaired smoothness on the green wafer. If defects such as residues or voids occur on the green wafer, there is a possibility of performance degradation in MLCCs. Therefore, it is necessary to further suppress defects generated during the green wafer manufacturing process.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2006-89354

[0009] Patent Document 2: Japanese Patent Application Publication No. 2015-202987

[0010] Patent Document 3: Japanese Patent Application Publication No. 2019-182925 Summary of the Invention

[0011] The technical problem to be solved by the present invention

[0012] The present invention was made to solve the above-mentioned technical problems, and its object is to provide a ceramic molding binder composition capable of producing green sheets and the like with excellent degreasing properties, strength, elongation, and smoothness based on heat-treated binders. Furthermore, the present invention also aims to provide a slurry composition containing the ceramic molding binder composition.

[0013] Technical means to solve technical problems

[0014] The inventors of this application have carefully studied the above-mentioned technical problems and found that by combining acrylic copolymers obtained by polymerizing specific monomers in a specified ratio and specific polyalkylene glycol compounds in a specified ratio, a ceramic molding binder composition and slurry composition that can achieve the above-mentioned objectives can be obtained.

[0015] That is, the present invention is a binder composition for ceramic molding, which contains 15-95% by mass of the following component (A) and 5-85% by mass of the following component (B).

[0016] Component (A): A copolymer having a weight average molecular weight of 50,000 to 1,000,000, comprising 70 to 99 mol% of structural units derived from monomer (a-1) represented by formula (1) below, 1 to 30 mol% of structural units derived from monomer (a-2) represented by formula (2) below, and 0 to 29 mol% of structural units derived from other copolymerizable monomers (a-3).

[0017] Equation (1)

[0018] CH2=CR 1 -COO-R 2

[0019] In equation (1), R 1 R represents a hydrogen atom or a methyl group. 2 Indicates alkyl groups having 1 to 8 carbon atoms.

[0020] Equation (2)

[0021] CH2=CR 3 -COO-R 4

[0022] In equation (2), R 3 R represents a hydrogen atom or a methyl group. 4 This refers to hydroxyalkyl groups having 1 to 2 hydroxyl groups and 1 to 8 carbon atoms;

[0023] Component (B): The compound represented by formula (3) below,

[0024] Equation (3)

[0025] R 5 O-(EO) p -(PO) q -H

[0026] In equation (3), R 5 It is an alkyl group with 9 carbon atoms, EO is vinyl oxide, PO is propylene oxide, p is the average number of moles of vinyl oxide added and p = 3 to 9, q is the average number of moles of propylene oxide added and q = 2 to 4, and p / q = 1.0 to 3.0.

[0027] Furthermore, on the other hand, the present invention is a slurry composition containing the above-mentioned binder composition for ceramic molding, ceramic powder, dispersant and organic dispersion medium.

[0028] Invention Effects

[0029] The binder composition for ceramic molding of the present invention can undergo slow thermal decomposition through heat treatment and can suppress the generation of residues. For example, when manufacturing MLCCs using the binder composition of the present invention, green sheets that exhibit high smoothness, excellent strength and elongation even when thinned can be obtained, thus meeting the requirements for thinning and multilayering of green sheets.

[0030] Furthermore, the slurry composition containing the binder composition for ceramic molding of the present invention is useful in the manufacture of thin-layer and multi-layer ceramic molded bodies, especially ceramic green sheets. Detailed Implementation

[0031] The following describes the embodiments of the present invention.

[0032] Furthermore, in this specification, the numerical range specified by the symbol "~" includes the values ​​at both ends of "~" (upper and lower limits). For example, "2~4" means 2 or more and 4 or less.

[0033] Furthermore, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid. In this invention, (meth)acrylates may be used alone or in combination with two or more. Therefore, when two components, acrylates and methacrylates, with the same ester moiety may be present, "(meth)acrylate" refers to acrylates and / or methacrylates.

[0034] <Binder Composition for Ceramic Molding>

[0035] The ceramic molding binder composition of the present invention (hereinafter, sometimes referred to simply as "binder composition") contains the following component (A) and the following component (B).

[0036] [Ingredients (A)]

[0037] The component (A) used in this invention (hereinafter sometimes referred to as "component (A) of this invention") is a copolymer obtained by polymerizing a monomer mixture containing monomer (a-1) represented by formula (1) and monomer (a-2) represented by formula (2) as essential components, and sometimes further containing other copolymerizable monomers (a-3). Component (A) of this invention may be used alone or in combination with two or more.

[0038] Equation (1)

[0039] CH2=CR 1 -COO-R 2

[0040] In equation (1), R 1 R represents a hydrogen atom or a methyl group. 2This refers to alkyl groups having 1 to 8 carbon atoms.

[0041] Equation (2)

[0042] CH2=CR 3 -COO-R 4

[0043] In equation (2), R 3 R represents a hydrogen atom or a methyl group. 4 This refers to a hydroxyalkyl group having 1 to 2 hydroxyl groups and 1 to 8 carbon atoms.

[0044] Monomer (a-1)

[0045] As shown in formula (1) above, the monomer (a-1) used to prepare component (A) of the present invention (hereinafter sometimes referred to as "monomer (a-1) of the present invention") is a mono(meth)acrylate alkyl ester having polymerizable functional groups. The monomer (a-1) of the present invention may be used alone or two or more at the same time.

[0046] From the perspective of the ease of polymerization of monomer (a-1), R in equation (1) 1 Methyl is preferred.

[0047] From the perspective of improving the degreasing properties of ceramic slurries prepared using component (A), R in formula (1) 2 The alkyl group has 1 to 8 carbon atoms, and the alkyl group can be any one of straight-chain, branched, cyclic, and combinations thereof. From the perspective of improving the strength of the green slices and suppressing the violent thermal decomposition in the temperature range of 300°C to 400°C during the degreasing process, the alkyl group preferably has 1 to 6 carbon atoms, more preferably 1 to 4, and even more preferably 1 to 2.

[0048] Examples of monomers (a-1) used in this invention include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, heptyl methacrylate, octyl methacrylate, and 2-ethylhexyl methacrylate.

[0049] Preferably, it is selected from at least one of the following groups: methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, amyl methacrylate, hexyl methacrylate, and cyclohexyl methacrylate.

[0050] More preferably, it is at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, and tert-butyl methacrylate.

[0051] More preferably, it is selected from at least one of the group consisting of methyl methacrylate and ethyl methacrylate.

[0052] The content of structural units derived from monomer (a-1) in component (A) is 70 to 99 mol%, preferably 85 to 99 mol%. By keeping the content of structural units derived from monomer (a-1) within this range, good strength of the green sheet can be achieved during the manufacture of the green sheet.

[0053] Furthermore, the percentage of structural units from monomer (a-1) in component (A) can be calculated by the proportion (mol%) of monomer (a-1) in the total percentage (mol%) of all monomers constituting component (A). The percentages of structural units from monomers (a-2) and (a-3), as described below, can also be calculated in the same manner. The total percentage of structural units from monomers (a-1), (a-2), and (a-3) is 100 mol%.

[0054] Monomer (a-2)

[0055] As shown in formula (2) above, the monomer (a-2) used to prepare component (A) of the present invention (hereinafter sometimes referred to as "monomer (a-2) of the present invention") is a mono(meth)acrylate alkyl ester having a hydroxyl group. The monomer (a-2) of the present invention may be used alone or two or more at the same time.

[0056] From the perspective of the ease of polymerization of monomer (a-2), R in equation (2) 3 Methyl is preferred.

[0057] R in equation (2) 4 It is a hydroxyalkyl group having 1 to 2 hydroxyl groups and 1 to 8 carbon atoms. The alkyl group can be any one of straight-chain, branched, cyclic, and combinations thereof, but is preferably straight-chain.

[0058] From the perspective of improving the uniformity of the prepared slurry composition and manufacturing ceramic molded bodies with high smoothness, the hydroxyl group preferably has one hydroxyl group. Furthermore, from the perspective of the strength of the green sheet during manufacturing, the number of carbon atoms is 1 to 8, preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 2.

[0059] Examples of monomers (a-2) in this invention include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, and glyceryl mono(meth)acrylate.

[0060] Preferably, it is selected from at least one of the group consisting of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, and 6-hydroxyhexyl methacrylate.

[0061] More preferably, it is at least one selected from the group consisting of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxybutyl methacrylate.

[0062] Further preferred is 2-hydroxyethyl (meth)acrylate.

[0063] The content of structural units from monomer (a-2) in component (A) is 1 to 30 mol%, preferably 1 to 15 mol%. By keeping the content of structural units from monomer (a-2) within this range, the uniformity of the prepared slurry composition can be improved, and a ceramic molded body with high smoothness can be manufactured.

[0064] Monomer (a-3)

[0065] The monomer (a-3) used to prepare component (A) of the present invention (hereinafter sometimes referred to as "monomer (a-3) of the present invention") is a monomer other than monomers (a-1) and (a-2), which is a monomer capable of copolymerizing with the aforementioned monomers (a-1) and (a-2).

[0066] Examples of monomers (a-3) used in this invention include unsaturated carboxylic acids such as acrylic acid and methacrylic acid; polymerizable aromatic unsaturated compounds such as styrene, p-styrenesulfonic acid, and indene; olefins such as isobutylene and isoprene; maleimides such as N-phenylmaleimide; other acrylamides; vinyl acetate; and acrylonitrile. These monomers may be used individually or in combination with two or more.

[0067] The content of structural units derived from monomer (a-3) in component (A) is 0 to 29 mol%, preferably 0 to 15 mol%. By keeping the content of structural units derived from monomer (a-3) within this range, high thermal decomposition is achieved, resulting in good degreasing properties.

[0068] [Preparation method of component (A)]

[0069] As a method for preparing component (A), known methods such as suspension polymerization, solution polymerization, and emulsion polymerization can be selected. Among these polymerization methods, suspension polymerization is preferred because it is easy to obtain component (A) with a high molecular weight.

[0070] There are no particular restrictions on the polymerization initiators used in suspension polymerization in organic solvent systems or solvent-free systems. Examples include peroxides such as benzoyl peroxide or azo initiators such as 2,2'-azobisisobutyronitrile. These polymerization initiators can be used alone or in combination with two or more.

[0071] During polymerization, chain transfer agents can be used to control the molecular weight of component (A). Commonly used compounds such as α-methylstyrene dimer and 1-thiopropanetriol can be used as chain transfer agents.

[0072] [Weight-average molecular weight of component (A)]

[0073] The weight-average molecular weight of component (A) of the present invention is 50,000 to 1,000,000, preferably 100,000 to 800,000, more preferably 200,000 to 700,000, further preferably 400,000 to 650,000, and particularly preferably 500,000 to 600,000. If the weight-average molecular weight of component (A) is too low, the strength of the green sheet obtained from the binder composition of the present invention may sometimes be insufficient. Furthermore, if the weight-average molecular weight of component (A) is too high, the slurry composition of the present invention is prone to stringing, which may sometimes impair the surface smoothness of the ceramic molded body (especially the ceramic green sheet).

[0074] The weight-average molecular weight of component (A) of the present invention can be calculated from polystyrene using gel permeation chromatography (GPC).

[0075] [Ingredient (B)]

[0076] The component (B) used in this invention (hereinafter sometimes referred to as "component (B) of this invention") is a compound represented by the following formula (3). Component (B) of this invention may be used alone or in combination with two or more other components.

[0077] Equation (3)

[0078] R 5 O-(EO) p -(PO) q -H

[0079] In equation (3), R 5It is an alkyl group with 9 carbon atoms, EO is vinyl oxide, PO is propylene oxide, p is the average number of moles of vinyl oxide added and p = 3 to 9, q is the average number of moles of propylene oxide added and q = 2 to 4, and p / q = 1.0 to 3.0.

[0080] In equation (3), R 5 The alkyl group has 9 carbon atoms and can be either branched or linear. Since it has good compatibility with component (A) and can improve the elongation of the manufactured green sheets, the alkyl group is preferably branched.

[0081] Examples of alkyl groups having 9 carbon atoms include nonyl, isononyl, and 3,5,5-trimethyl-1-hexyl, with isononyl and 3,5,5-trimethyl-1-hexyl being preferred.

[0082] Since p in formula (3) is the average number of moles of vinyl oxide added, p is not limited to an integer and can also be a decimal. p is a number from 3 to 9, preferably 5 to 9, and more preferably 7 to 8. When p is too small, the compatibility between component (A) and component (B) will decrease, and the ceramic molded body formed from the slurry composition will have difficulty exhibiting flexibility, and elongation may sometimes decrease. On the other hand, when p is too large, thermal decomposition near 300°C is difficult to carry out during the degreasing process, and thermal decomposition will occur violently in the temperature range of 300°C to 400°C, which may sometimes produce fine voids on the green sheet, resulting in impaired smoothness.

[0083] Since q in formula (3) represents the average number of moles added to the propylene oxide group, q is not limited to an integer and can also be a decimal. q is a number from 2 to 4, preferably from 2.5 to 3.5. When q is too small, the compatibility of component (B) with the organic dispersion medium contained in the slurry composition decreases, the slurry composition becomes uneven, and the smoothness of the ceramic molded body may sometimes decrease. When q is too large, the compatibility of component (A) with component (B) decreases, making it difficult to achieve the softness of the ceramic molded body formed from the slurry composition, and the elongation may sometimes decrease.

[0084] The ratio of p to q in formula (3) (i.e., p / q) is 1.0 to 3.0, preferably 1.6 to 3.0, and more preferably 2.4 to 3.0. When p / q is too small, the compatibility between component (A) and component (B) decreases, making it difficult to achieve the softness of the ceramic molded body formed from the slurry composition, and the elongation may sometimes decrease. On the other hand, when p / q is too large, the compatibility of component (B) with the organic dispersion medium contained in the slurry composition decreases, the slurry composition becomes uneven, and the smoothness of the ceramic molded body may sometimes decrease. In addition, sometimes due to a relatively excessive amount of vinyl oxide, thermal decomposition is difficult and degreasing properties decrease.

[0085] Component (B) of the present invention can be prepared, for example, by adding an alcohol as a starting material to ethylene oxide corresponding to EO, followed by adding propylene oxide corresponding to PO. The addition of alkyl epoxides is well known to those skilled in the art, and they can prepare component (B) by appropriately setting the addition conditions.

[0086] [The content of each component (A) and component (B)]

[0087] The content of component (A) in the ceramic molding binder composition of the present invention is 15-95% by mass, preferably 40-95% by mass, and more preferably 70-95% by mass. Furthermore, the content of component (B) in the ceramic molding binder composition of the present invention is 5-85% by mass, preferably 5-60% by mass, and more preferably 5-30% by mass. Additionally, the total content of components (A) and (B) is 100% by mass.

[0088] If the content of component (B) is too high, the ceramic molded body (especially green sheet) formed from the slurry composition of the present invention will not have sufficient strength, and the smoothness of the molded body may sometimes be impaired. If the content of component (B) is too low, the elongation of the ceramic molded body (especially green sheet) formed from the slurry composition of the present invention may sometimes be impaired.

[0089] <Slurry Composition>

[0090] The slurry composition of the present invention contains the above-mentioned binder composition for ceramic molding, ceramic powder, dispersant, and organic dispersion medium. Each of the ceramic powder, dispersant, and organic dispersion medium can be used individually or in combination with two or more.

[0091] [Ceramic Powder]

[0092] The ceramic powder used in this invention can be either an oxide-based ceramic powder or a non-oxide-based ceramic powder. Examples of oxide-based ceramic powders include alumina, titanium dioxide, zirconium oxide, barium titanate, and lead zirconium titanate. Examples of non-oxide-based ceramic powders include silicon carbide and silicon nitride.

[0093] The average diameter of the ceramic powder is preferably 0.05 to 50.0 μm, more preferably 0.10 to 10.0 μm, even more preferably 0.20 to 5.00 μm, and particularly preferably 0.20 to 1.00 μm.

[0094] In addition, in this specification, the average diameter of ceramic powder refers to the particle size at which the cumulative volume of the detection frequency is 50% in the volume-based particle size distribution obtained by measuring using a laser diffraction scattering particle size distribution measuring device, i.e., the median particle size d50.

[0095] [Dispersant]

[0096] The dispersant used in this invention is not particularly limited, and any one of cationic dispersants, anionic dispersants, nonionic dispersants, and amphoteric dispersants can be used, or a polymeric dispersant can be used.

[0097] Examples of cationic dispersants include polyamine dispersants. Examples of anionic dispersants include carboxylic acid dispersants, phosphate ester dispersants, sulfate ester dispersants, and sulfonate ester dispersants. Examples of nonionic dispersants include polyethylene glycol dispersants. Examples of polymeric dispersants include high molecular weight polycarboxylic acid dispersants.

[0098] [Organic Dispersion Media]

[0099] From the perspective of the sheet-forming properties of the slurry composition, a highly volatile organic dispersion medium is preferred as the organic dispersion medium used in this invention. A highly volatile organic dispersion medium refers to an organic solvent that is liquid at 20°C and has a boiling point of 150°C or lower, preferably 100°C or lower, such as methanol, ethanol, toluene, acetone, methyl ethyl ketone, etc.

[0100] These organic dispersion media can be used alone or in combination with two or more, but it is preferred to use two or more organic dispersion media simultaneously. When using multiple organic dispersion media simultaneously, it is preferred to use polar dispersion media such as ethanol or methyl ethyl ketone and non-polar dispersion media such as toluene, with a mass ratio (polar dispersion media: non-polar dispersion media) preferably of 9:1 to 1:9, more preferably of 4:1 to 1:4, and even more preferably of 2:1 to 1:2.

[0101] [Admixture Composition]

[0102] Relative to 100 parts by weight of ceramic powder, the content of the binder composition for ceramic molding in the slurry composition of the present invention is preferably 0.1 to 100 parts by weight, more preferably 1 to 50 parts by weight, and even more preferably 5 to 20 parts by weight.

[0103] Furthermore, relative to 100 parts by weight of ceramic powder, the content of dispersant in the slurry composition of the present invention is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, and even more preferably 0.5 to 2 parts by weight.

[0104] Furthermore, relative to 100 parts by weight of ceramic powder, the content of organic dispersion medium in the slurry composition of the present invention is preferably 10 to 500 parts by weight, more preferably 20 to 200 parts by weight, and even more preferably 25 to 100 parts by weight.

[0105] [Other ingredients that may be included in the slurry composition]

[0106] To the extent that it does not impair the effects of the present invention, in addition to the binder composition, ceramic powder, dispersant, and organic dispersion medium described above, the slurry composition of the present invention may contain other components different from those described above. Examples of such other components include, for instance, defoamers.

[0107] <Methods for Manufacturing Ceramic Molded Bodies>

[0108] The slurry composition of the present invention can be used to manufacture ceramic molded articles such as green sheets. The method is not particularly limited, and known methods can be employed. Examples of known methods include stamping or sheet forming.

[0109] The process of manufacturing green sheets as ceramic molded bodies by sheet forming is briefly described. In sheet forming, a slurry composition is coated onto a support, and the slurry composition is dried to produce green sheets.

[0110] The support used in the sheet forming method is not particularly limited, and known supports can be used. Examples of materials that can be used as supports include polyethylene terephthalate, polycarbonate, stainless steel (SUS), and glass. Examples of coating methods include known coating methods such as the doctor blade coating.

[0111] The drying method for the coated slurry composition is not particularly limited, and drying can be performed using a dryer through known methods. Examples of dryers include drying ovens and thermal dryers. The drying atmosphere can be atmospheric or an inert gas atmosphere such as nitrogen. The drying pressure can be atmospheric or reduced pressure. The drying temperature and time vary depending on the composition of the slurry composition, with temperatures ranging from 30 to 150°C and times ranging from 5 to 60 minutes. Furthermore, it is preferable to coat the slurry composition in a manner that results in a film thickness of 0.5 to 20.0 μm for the green sheet obtained after drying.

[0112] Next, the process of manufacturing MLCCs using the obtained green wafers will be briefly described. The green wafer is peeled off from the support, and a conductive paste forming the internal electrodes is applied to its surface using screen printing or similar methods. Multiple wafers are alternately stacked and heated and pressed together to obtain a laminate. This laminate is then cut to form a chip-like laminate. To remove organic components from the chip-like laminate, a degreasing treatment is performed, followed by firing to obtain a ceramic sintered product. External electrodes are sintered onto the end faces of the ceramic sintered product to manufacture MLCCs.

[0113] There are no particular limitations on the degreasing method, and known methods can be used. For example, by using an electric furnace or similar means, the raw sheet can be heat-treated in an inert gas atmosphere, for example, at 350–500°C for 30–150 minutes, to remove the binder composition, that is, to remove component (A) and component (B).

[0114] Example

[0115] The present invention will now be described with reference to more detailed embodiments.

[0116] [abbreviation]

[0117] The meanings of the abbreviations used in the following table are as follows.

[0118] MMA: Methyl methacrylate

[0119] IBMA: Isobutyl methacrylate

[0120] HEMA: 2-Hydroxyethyl methacrylate

[0121] St: Styrene

[0122] INA: Isononol

[0123] PVB: Polyvinyl butyral (manufactured by SEKISUI CHEMICAL CO.,LTD. as "S-LEC (registered trademark) BM-2")

[0124] <Synthesis of Component (A)>

[0125] [Synthesis Example 1: Synthesis of Component (A-1)]

[0126] An aqueous solution was prepared by adding 600 g of deionized water and 0.6 g of polyvinyl alcohol (POVALPVA-224E manufactured by KURARAY CO.,LTD.) to a 1 L separable flask equipped with a stirrer, thermometer, condenser, and nitrogen inlet tube, and stirring while heating. Then, a mixture of 187.2 g (1.87 mol) of methyl methacrylate as monomer (a-1), 12.8 g (0.10 mol) of 2-hydroxyethyl methacrylate as monomer (a-2), 3.2 g of PEROYL (registered trademark) OPP manufactured by NOF CORPORATION as polymerization initiator, and 0.6 g of NOFMER MSD (α-methylstyrene dimer manufactured by NOF CORPORATION) as chain transfer agent was added to the aqueous solution and heated at 50 °C for 3 hours to obtain a granular copolymer. Furthermore, the mixture containing the particulate copolymer is heated to 70°C and stirred at 70°C for 2 hours to completely decompose the polymerization initiator.

[0127] Next, the mixture was cooled to room temperature and filtered. This yielded a moist, granular copolymer. The moist, granular copolymer was spread on an aluminum tray and placed in a 40°C desiccator to thoroughly remove moisture, yielding component (A-1) as the granular copolymer.

[0128] [Synthesis Example 2: Synthesis of Component (A-2)]

[0129] The amount of methyl methacrylate used was changed to 83.0 g (0.83 mol), and 106.2 g (1.23 mol) of isobutyl methacrylate as monomer (a-1) was further used. The amount of 2-hydroxyethyl methacrylate used was changed to 10.8 g (0.08 mol), and the amount of PEROYL (registered trademark) OPP used was changed to 2.8 g. Otherwise, the copolymer component (A-2) was obtained by the same method as in Synthesis Example 1.

[0130] [Synthesis Example 3: Synthesis of Component (A-3)]

[0131] The copolymer component (A-3) was obtained by using 190.8 g (2.22 mol) of isobutyl methacrylate as monomer (a-1) instead of methyl methacrylate, changing the amount of 2-hydroxyethyl methacrylate to 9.2 g (0.07 mol), and changing the amount of PEROYL (registered trademark) OPP to 3.0 g, except that methyl methacrylate was not used.

[0132] [Synthesis Example 4: Synthesis of Component (A-4)]

[0133] The amount of methyl methacrylate used was changed to 150.8 g (1.51 mol), the amount of 2-hydroxyethyl methacrylate used was changed to 49.2 g (0.38 mol), and the amount of PEROYL (registered trademark) OPP used was changed to 3.0 g. Otherwise, the copolymer component (A-4) was obtained by the same method as in Synthesis Example 1.

[0134] [Synthesis Example 5: Synthesis of Component (A-5)]

[0135] The amount of methyl methacrylate used was changed to 84.4 g (0.84 mol), and 95.8 g (1.11 mol) of isobutyl methacrylate as monomer (a-1) was further used. The amount of 2-hydroxyethyl methacrylate used was changed to 11.0 g (0.08 mol), and 8.8 g (0.08 mol) of styrene as monomer (a-3) was further used. The amount of PEROYL (registered trademark) OPP used was changed to 2.9 g. Otherwise, the copolymer component (A-5) was obtained by the same method as in Synthesis Example 1.

[0136] [Weight-average molecular weight]

[0137] The weight-average molecular weights of the copolymers (i.e., components (A-1) to (A-5)) obtained in Synthesis Examples 1 to 5 were determined by gel permeation chromatography (GPC) under the following conditions.

[0138] Device: Manufactured by TOSOH CORPORATION, HLC-8220

[0139] Column: SHOWA DENKO KK, KF-805L

[0140] Standard material: polystyrene

[0141] Eluent: THF (Tetrahydrofuran)

[0142] Flow rate: 1.0 ml / minute

[0143] Column temperature: 40℃

[0144] Detector: RI (Differential Refractive Index Detector)

[0145] Table 1 lists the components (A-1) to (A-5) of the copolymers obtained in Synthesis Examples 1 to 5, the types of monomers used in the synthesis of these copolymers, the content of structural units from these monomers, and the weight-average molecular weight of these copolymers.

[0146] [Table 1]

[0147]

[0148] <Synthesis of component (B) or component (B')>

[0149] [Synthesis Example 6: Synthesis of Component (B-1)]

[0150] 433 g of isononol ("OXOCOL 900" manufactured by KH Neochem Co., Ltd.) and 10 g of potassium hydroxide were added to a 5 L autoclave. After nitrogen purging, the mixture was heated to 120 °C with stirring. Then, 1058 g of ethylene oxide was added dropwise over 6 hours using a dropping device, and the reaction was continued at 120 °C for 1 hour. Next, 523 g of propylene oxide was added dropwise over 4 hours using a dropping device, and the reaction was continued at 120 °C for 1 hour. The crude product was then removed from the autoclave and neutralized with hydrochloric acid to a pH of 6–7 as determined by JIS K1557-5. Next, to remove water from the hydrochloric acid, the neutralized crude product was subjected to reduced pressure treatment at 100 °C for 1 hour. Finally, the salt was removed by filtration, yielding 1913 g of component (B-1).

[0151] [Synthesis Example 7: Synthesis of Component (B-2)]

[0152] Except that the amount of ethylene oxide used was changed to 790g, 1659g of the composition (B-2) was obtained by the same method as in Synthesis Example 6.

[0153] [Synthesis Example 8: Synthesis of Component (B-3)]

[0154] Except that the amount of ethylene oxide used was changed to 530g, 1412g of the composition (B-3) was obtained by the same method as in Synthesis Example 6.

[0155] [Synthesis Example 9: Synthesis of Component (B-4)]

[0156] Except that the amount of ethylene oxide used was changed to 1190g, 2039g of the composition (B-4) was obtained by the same method as in Synthesis Example 6.

[0157] [Comparative Synthesis Example 1: Synthesis of Component (B'-1)]

[0158] Except for changing the amount of isononol to 310g, the amount of ethylene oxide to 1130g, and the amount of propylene oxide to 370g, 1720g of composition (B'-1) was obtained by the same method as in Synthesis Example 6.

[0159] [Comparative Synthesis Example 2: Synthesis of Component (B'-2)]

[0160] Except for changing the amount of ethylene oxide used to 400g and the amount of propylene oxide used to 870g, 1618g of composition (B'-2) was obtained by the same method as in Synthesis Example 6.

[0161] The components (B-1) to (B-4), (B'-1), and (B'-2) obtained from Synthetic Examples 6 to 9, Comparative Synthetic Examples 1 to 2, and the starting materials of these components, as well as R in the above formula (3), are used. 5 p, q and p / q are recorded in Table 2.

[0162] In addition, components (B-1) to (B-4) belong to components (B) of the present invention, but p or q in formula (3) of components (B'-1) and (B'-2) are outside the specified range, and p / q is also outside the specified range, so they do not belong to components (B) of the present invention.

[0163] [Table 2]

[0164] Synthesis example 6 Synthesis Example 7 Synthesis example 8 Synthesis example 9 Comparative Synthesis Example 1 Comparative Synthesis Example 2 Ingredient (B) B-1 B-2 B-3 B-4 B’-1 B’-2 Starting materials INA INA INA INA INA INA <![CDATA[R 5 ]]> Irrenji Irrenji Irrenji Irrenji Irrenji Irrenji p 8 6 4 9 12 3 q 3 3 3 3 3 5 p / q 2.7 2.0 1.3 3.0 4.0 0.6

[0165] <Examples 1-10 and Comparative Examples 1-5>

[0166] [Preparation of binder compositions for ceramic molding]

[0167] Using the prepared components (A) and (B) respectively, the components were mixed according to the combinations and mixing ratios shown in Tables 3 and 4 below, such that the total amount of components (A) and (B) was 10 parts by mass, toluene was 10 parts by mass, and ethanol was 10 parts by mass, to obtain a binder composition for ceramic molding. In Comparative Example 3, PVB was used as component (A') instead of component (A).

[0168] [Preparation of the slurry composition]

[0169] 100 parts by weight of barium titanate (manufactured by SAKAI CHEMICAL INDUSTRY CO.,LTD., “BT-03”, median particle size d50 on a volume basis: 0.3 μm), 0.8 parts by weight of a high molecular weight polycarboxylic acid dispersant (manufactured by NOFCORPORATION, “MALIALIM (registered trademark) SC-0505K”), 18 parts by weight of toluene and 18 parts by weight of ethanol as organic dispersion media, and 100 parts by weight of zirconia balls with a particle size of 1 mm were placed in a ball mill and mixed for 8 hours. Then, 30 parts by weight of the above-prepared ceramic forming binder composition were added, and the mixture was further mixed for 12 hours. The zirconia balls were then filtered out, thereby preparing a slurry composition.

[0170] [The Production of Raw Film]

[0171] The obtained slurry composition (i.e., each slurry composition of Examples 1-10 and Comparative Examples 1-5) was coated in a sheet with a thickness of 20 μm onto a PET film used as a carrier by a doctor blade method, and then dried at 90°C for 10 minutes to produce a raw sheet.

[0172] The following evaluation tests were conducted on the above-mentioned binder composition for ceramic molding and the green sheet.

[0173] [Degreasing speed]

[0174] The binder composition for ceramic molding was placed on a hot plate at 100°C for 30 minutes to dry it, removing toluene and ethanol, thereby obtaining a mixed dried product of components (A) and (B). Next, approximately 5 mg of the mixed dried product was placed in an aluminum pan and heated from room temperature to 400°C at a rate of 10°C / min using a thermogravimetric analyzer (Hitachi High-Tech Corporation, STA7200) under a nitrogen atmosphere. After holding at 400°C for 30 minutes, it was cooled to room temperature.

[0175] Reduce temperature T by 50% of weight 50 90% weight reduction at temperature T 90 The degreasing rate is evaluated using the following criteria, calculated by the formula ΔW / ΔT.

[0176] ΔW / ΔT=(90-50) / (T 90 -T 50 )

[0177] (Evaluation criteria for degreasing speed)

[0178] ◎: ΔW / ΔT is less than 1.00

[0179] ○: ΔW / ΔT is greater than 1.00 and less than 1.20

[0180] ×: ΔW / ΔT is 1.20 or higher.

[0181] [Defatted]

[0182] At the end of the heat treatment in the above degreasing rate test, the residue rate is calculated by the ratio of the residual mass W2 to the amount of mixed dried material W1 before treatment, and the degreasing performance is evaluated according to the following criteria.

[0183] Residue percentage (mass%) = (Residual mass W2 at the end of heat treatment) / (Amount of mixed dried material W1 before heat treatment) × 100

[0184] (Evaluation criteria for degreasing properties)

[0185] ◎: Residue rate less than 0.5% by mass

[0186] ○: The residue rate is 0.5% by mass or more and less than 1.0% by mass.

[0187] ×: Residue rate is 1.0% by mass or more.

[0188] [Raw film strength]

[0189] Strips with a length of 60 mm and a width of 20 mm were cut from the manufactured green sheet. Tensile tests were performed using a universal testing machine (manufactured by Shimadzu Corporation: EZ-SX) at a speed of 10 mm / min to determine the tensile strength. The strength of the green sheet was evaluated according to the following standards.

[0190] (Evaluation criteria for raw film strength)

[0191] ◎: Tensile strength is 4.50 N / mm 2 above

[0192] ○: Tensile strength is 4.00 N / mm 2 Above and less than 4.50 N / mm 2

[0193] ×: Tensile strength less than 4.00 N / mm 2

[0194] [Elongation of raw slices]

[0195] The test pieces were prepared and tensile tests were conducted in the same manner as the evaluation of the strength of the raw sheets described above. The elongation at break (=100×(L-L0) / L0, L0: gauge length, L: gauge length at break) was measured, and the elongation of the raw sheets was evaluated according to the following criteria.

[0196] (Evaluation criteria for the elongation of raw film)

[0197] ◎: Elongation at break is 3.50% or more

[0198] ○: Elongation at break is 3.00% or more but less than 3.50%

[0199] ×: Elongation at break is less than 3.00%

[0200] [Smoothness of raw film]

[0201] The surface roughness of the manufactured green sheet was measured using a surface roughness meter, and the arithmetic mean roughness (μm) was calculated. The smoothness of the green sheet was evaluated according to the following criteria.

[0202] (Evaluation criteria for the smoothness of raw film)

[0203] ◎: Arithmetic mean roughness is less than 0.050 μm

[0204] ○: Arithmetic mean roughness is greater than or equal to 0.050 μm and less than 0.060 μm.

[0205] ×: Arithmetic mean roughness is 0.060 μm or higher.

[0206] The evaluation results of the ceramic slurries of Examples 1-10 and Comparative Examples 1-5 (i.e., the parameters for calculating the degreasing rate and the degreasing rate, residue ratio and degreasing property obtained from the residue ratio, tensile strength and green sheet strength obtained from the tensile strength, elongation at break and green sheet elongation obtained from the elongation at break, arithmetic mean roughness and green sheet smoothness obtained from the arithmetic mean roughness) are recorded in Tables 3 and 4.

[0207] [Table 3]

[0208]

[0209] [Table 4]

[0210]

[0211] As shown in Table 3, the adhesive compositions of Examples 1-10 and the raw sheets using these compositions showed good results in all evaluations.

[0212] On the other hand, as shown in Table 4, in Comparative Example 1 where the content of component (B) was excessive, the strength and smoothness of the raw slices were insufficient.

[0213] In Comparative Example 2, where the content of component (A) was excessive, the raw slices could not be given sufficient softness, and therefore the elongation of the raw slices was insufficient.

[0214] In Comparative Example 3, where PVB (polyvinyl butyral) was used as component (A'), the adhesive composition exhibited poor thermal decomposition, resulting in residue and insufficient degreasing.

[0215] In Comparative Example 4, where a component (B'-1) with an excessively high p / q ratio was used as component (B'), the raw sheet lacked sufficient smoothness. Furthermore, severe thermal decomposition of the adhesive composition was observed.

[0216] In Comparative Example 5, where a component (B'-2) with an excessively small p / q ratio was used as component (B'), the compatibility between component (A) and component (B) was insufficient, and the plasticizing effect could not be fully exerted, resulting in insufficient elongation of the raw sheet.

[0217] Industrial applicability

[0218] The green sheets obtained from the slurry composition of the present invention can be used, for example, in the manufacture of single-layer ceramic substrates for chip resistors or for mounting light-emitting elements.

[0219] [Related Application]

[0220] This application claims priority to Japanese Patent Application No. 2021-165445, filed on October 7, 2021, the entire contents of which are incorporated herein by reference.

Claims

1. A ceramic molding binder composition comprising 15 to 95 mass% of the following component (A) and 5 to 85 mass% of the following component (B), Component (A): a copolymer having a content of structural units from a monomer (a-1) represented by the following formula (1) of 70 to 99 mol%, a content of structural units from a monomer (a-2) represented by the following formula (2) of 1 to 30 mol%, and a content of structural units from other copolymerizable monomers (a-3) of 0 to 29 mol%, and having a weight average molecular weight of 50,000 to 1,000,000, Formula (1) CH2=CR 1 -COO-R 2 In formula (1), R 1 represents a hydrogen atom or a methyl group, R 2 represents an alkyl group having 1 to 8 carbon atoms, Formula (2) CH2=CR 3 -COO-R 4 In formula (2), R 3 represents a hydrogen atom or a methyl group, R 4 represents a hydroxyalkyl group having 1 to 2 hydroxyl groups and having 1 to 8 carbon atoms; Component (B): a compound represented by the following formula (3), Formula (3) R 5 O-(EO) p -(PO) q -H In formula (3), R 5 is an alkyl group having 9 carbon atoms, EO is an ethylene oxide group, PO is a propylene oxide group, p is the average addition mole number of the ethylene oxide group and p = 3 to 9, q is the average addition mole number of the propylene oxide group and q = 2 to 4, and p / q = 1.0 to 3.

0.

2. A slurry composition comprising the ceramic molding binder composition according to claim 1, a ceramic powder, a dispersant, and an organic dispersing medium.

3. The slurry composition of claim 2, wherein, The slurry composition contains 0.1 to 100 mass parts of the ceramic molding binder composition, 0.1 to 10 mass parts of the dispersant, and 10 to 500 mass parts of the organic dispersing medium, with respect to 100 mass parts of the ceramic powder.

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