CN116829643A

CN116829643A - (meth) acrylic resin composition, inorganic fine particle dispersion slurry composition, and inorganic fine particle dispersion molded article

Info

Publication number: CN116829643A
Application number: CN202280012445.4A
Authority: CN
Inventors: 大塚丈; 山内健司; 松洼龙也; 金子由实
Original assignee: Sekisui Chemical Co Ltd
Current assignee: Sekisui Chemical Co Ltd
Priority date: 2021-06-21
Filing date: 2022-06-20
Publication date: 2023-09-29
Also published as: WO2022270460A1; TW202311318A; KR20240022439A; JPWO2022270460A1

Abstract

Disclosed is a (meth) acrylic resin composition which has excellent decomposability at low temperatures and can improve the dispersibility of inorganic fine particles and the aggregation-inhibiting effect. The present invention also provides an inorganic fine particle dispersion slurry composition and an inorganic fine particle dispersion molded article each using the (meth) acrylic resin composition. The present invention relates to a (meth) acrylic resin composition containing a (meth) acrylic resin and an organic solvent, wherein the (meth) acrylic resin composition satisfies any one of the following (1) to (3), and the organic solvent contains OH groups in a weight concentration of 9.0 wt% or more and 28.0 wt% or less. (1) The (meth) acrylic resin contains a high molecular weight (meth) acrylic resin (a) having a weight average molecular weight of 12 to 30 ten thousand, and the OH group concentration in the high molecular weight (meth) acrylic resin (a) is 0.4 to 2.0 wt%. (2) The (meth) acrylic resin contains a high molecular weight (meth) acrylic resin (B) having a weight average molecular weight of more than 30 ten thousand and 50 ten thousand or less, and the OH group concentration in the high molecular weight (meth) acrylic resin (B) is 1.3 wt% or more and 3.5 wt% or less. (3) The (meth) acrylic resin contains a low molecular weight (meth) acrylic resin (C) having a weight average molecular weight of 0.5 to 10 ten thousand, the concentration by weight of OH groups contained in the low molecular weight (meth) acrylic resin (C) is 1.3 to 3.5 wt%, and the concentration by weight of S atoms contained in the (meth) acrylic resin is 250 to 20000 ppm.

Description

(meth) acrylic resin composition, inorganic fine particle dispersion slurry composition, and inorganic fine particle dispersion molded article

Technical Field

The present invention relates to a (meth) acrylic resin composition, an inorganic fine particle dispersion slurry composition, and an inorganic fine particle dispersion molded article.

Background

A composition in which inorganic fine particles such as ceramic powder and glass particles are dispersed in a binder resin is used for the production of laminated electronic components such as laminated ceramic capacitors.

Such a laminated ceramic capacitor is generally manufactured by the following method. First, after adding additives such as a plasticizer and a dispersant to a solution obtained by dissolving a binder resin in an organic solvent, ceramic raw material powder is added and uniformly mixed using a ball mill or the like to obtain an inorganic fine particle dispersion slurry composition.

The obtained inorganic fine particle dispersion slurry composition is cast on the surface of a support such as a polyethylene terephthalate film or a SUS plate subjected to a mold release treatment using a doctor blade, a reverse roll coater or the like, and volatile components such as an organic solvent are distilled off and then peeled off from the support to obtain a ceramic green sheet.

Next, a conductive paste to be an internal electrode is applied to the obtained ceramic green sheet by screen printing or the like, and a plurality of the conductive pastes are stacked, heated, and pressure-bonded to obtain a laminate. The obtained laminate is heated, subjected to a treatment for removing components such as a binder resin by thermal decomposition, so-called degreasing treatment, and then fired, thereby obtaining a ceramic fired body having an internal electrode. Further, an external electrode is applied to an end face of the obtained ceramic fired body, and firing is performed, thereby completing the laminated ceramic capacitor.

In recent years, as the multilayer ceramic capacitor has been miniaturized, the inorganic fine particles used have also been miniaturized. If the fine inorganic fine particles are aggregated in the paste, voids tend to remain in the degreasing step and the firing step, or the dispersibility of the inorganic fine particles is reduced when the laminated ceramic capacitor is produced, and as a result, the electrical characteristics of the product are reduced.

As the binder resin, for example, ethylcellulose and polyvinyl acetal resin (PVB) are generally used. For example, patent document 1 discloses a method of dispersing ceramic powder efficiently in a composition using these binders. Specifically, disclosed is: a method in which ceramic powder such as calcium titanate is crushed once in a solvent such as ethanol, and then a resin such as polyvinyl butyral resin or ethylcellulose resin is added.

Patent document 2 discloses that: in addition to polyvinyl butyral and cellulose polymers, an acrylic resin or the like is used as a binder.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2011-84433

Patent document 2: japanese patent laid-open No. 2020-109761

Disclosure of Invention

Problems to be solved by the application

However, the polyvinyl acetal resin described in patent document 1 has a problem that it has a high decomposition temperature and cannot be used for applications requiring low-temperature firing, for example, for applications using a metal such as copper which is easily oxidized, low-melting glass, or the like.

Patent document 2 describes the use of an acrylic resin, but when fine inorganic particles having an average particle diameter of less than 1 μm are used, there is a problem that dispersibility is deteriorated. In addition, the acrylic resin described in patent document 2 has a problem in that deterioration due to oxidation occurs in degreasing requiring a high firing temperature.

The purpose of the present application is to provide a (meth) acrylic resin composition which has excellent degradability at low temperatures and can improve the dispersibility of inorganic fine particles and the aggregation-inhibiting effect. Further, the object is to provide an inorganic fine particle dispersion slurry composition and an inorganic fine particle dispersion molded article each using the (meth) acrylic resin composition.

Means for solving the problems

The present application [1] relates to a (meth) acrylic resin composition containing a (meth) acrylic resin and an organic solvent, wherein the (meth) acrylic resin composition satisfies any one of the following (1) to (3), and the organic solvent contains OH groups in a weight concentration of 9.0 wt% or more and 28.0 wt% or less.

(1) The (meth) acrylic resin contains a high molecular weight (meth) acrylic resin (a) having a weight average molecular weight of 12 to 30 ten thousand, and the OH group concentration in the high molecular weight (meth) acrylic resin (a) is 0.4 to 2.0 wt%.

(2) The (meth) acrylic resin contains a high molecular weight (meth) acrylic resin (B) having a weight average molecular weight of more than 30 ten thousand and 50 ten thousand or less, and the OH group concentration in the high molecular weight (meth) acrylic resin (B) is 1.3 wt% or more and 3.5 wt% or less.

(3) The (meth) acrylic resin contains a low molecular weight (meth) acrylic resin (C) having a weight average molecular weight of 0.5 to 10 ten thousand, the concentration by weight of OH groups contained in the low molecular weight (meth) acrylic resin (C) is 1.3 to 3.5 wt%, and the concentration by weight of S atoms contained in the (meth) acrylic resin is 250 to 20000 ppm.

The present application [2] relates to the (meth) acrylic resin composition of the present application [1], which satisfies (1) and contains a low molecular weight (meth) acrylic resin having a weight average molecular weight of 0.5 to 10 ten thousand, wherein the low molecular weight (meth) acrylic resin contains OH groups in a weight concentration of 1.3 to 3.5 wt% relative to 100 parts by weight of the high molecular weight (meth) acrylic resin (A), and the low molecular weight (meth) acrylic resin is contained in an amount of 0.1 to 10 parts by weight.

The application [3] relates to the (meth) acrylic resin composition of the application [1], which satisfies (1) or (2), and the solubility of the high molecular weight (meth) acrylic resin (A) or (B) in ethanol is 10 parts by weight or more per 100 parts by weight of ethanol.

The present application [4] relates to the (meth) acrylic resin composition of the present application [1] or [3], which satisfies (1) or (2), and the high molecular weight (meth) acrylic resin (a) or (B) contains 79% by weight or more and 96% by weight or less of the structural unit represented by the following formula (a) and 3.1% by weight or more and 17% by weight or less of the structural unit represented by the following formula (B) relative to the total structural units.

[ chemical formula 1]

In the formula (a), R ¹ Represents a linear or branched alkyl group having 1 to 8 carbon atoms, wherein R is represented by the formula (b) ² Represents a linear or branched alkyl group having 2 to 4 carbon atoms, at least 1 of which is substituted with an OH group.

The application [5] relates to the (meth) acrylic resin composition of the application [1], [3] or [4], which satisfies (1) or (2), and the ratio of the weight concentration of OH groups contained in the organic solvent to the weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin (A) or (B) (the weight concentration of OH groups contained in the organic solvent/the weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin (A) or (B)) is 4.5 to 46.2.

The present application [6] relates to the (meth) acrylic resin composition of the present application [1], [3], [4] or [5], which satisfies (2), and the (meth) acrylic resin is composed of only the high molecular weight (meth) acrylic resin (B), and the weight concentration of S atoms contained in the (meth) acrylic resin is 250ppm to 20000 ppm.

The present application [7] relates to an inorganic fine particle-dispersed slurry composition comprising the (meth) acrylic resin composition according to any one of the present application [1] to [6], inorganic fine particles and a plasticizer.

The present application [8] relates to an inorganic fine particle dispersion molded article obtained by using the inorganic fine particle dispersion slurry composition of the present application [7 ].

The present application will be described in detail below.

The present inventors have found that by using a (meth) acrylic resin having a predetermined weight average molecular weight, OH group weight concentration, and S atom weight concentration in combination with an organic solvent having an OH group weight concentration of 9.0 wt% or more and 28.0 wt% or less, a binder resin can exhibit extremely excellent decomposability even at low temperatures, and can also improve dispersibility of inorganic fine particles and aggregation inhibition effect, and have completed the present application.

The (meth) acrylic resin composition of the present invention contains a (meth) acrylic resin.

The (meth) acrylic resin satisfies any one of the following (1) to (3).

(3) The (meth) acrylic resin contains a low molecular weight (meth) acrylic resin (C) having a weight average molecular weight of 0.5 to 10 ten thousand, the concentration by weight of OH groups contained in the low molecular weight (meth) acrylic resin is 1.3 to 3.5 wt%, and the concentration by weight of S atoms contained in the (meth) acrylic resin is 250 to 20000 ppm. By satisfying the above configuration, the dispersibility of the inorganic fine particles can be sufficiently improved when the inorganic fine particle-dispersed slurry composition is produced. In addition, aggregation of the inorganic fine particles can be suppressed.

< high molecular weight (meth) acrylic resin (A) >)

In the (meth) acrylic resin composition of the present invention satisfying the above (1), the (meth) acrylic resin contains a high molecular weight (meth) acrylic resin (a).

The weight average molecular weight of the high molecular weight (meth) acrylic resin (a) is 12 to 30 ten thousand.

When the content is within the above range, the dispersibility of the inorganic fine particles can be sufficiently improved when the inorganic fine particle-dispersed slurry composition is produced. In addition, aggregation of the inorganic fine particles can be suppressed.

The weight average molecular weight is preferably 15 ten thousand or more, more preferably 18 ten thousand or more, preferably 25 ten thousand or less, more preferably 22 ten thousand or less.

When the content is within the above range, the inorganic fine particle-dispersed slurry composition can have a sufficient viscosity and can be improved in printability.

The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the high molecular weight (meth) acrylic resin (A) is preferably 2 or more, more preferably 8 or less.

When the viscosity is within the above range, the viscosity of the inorganic fine particle-dispersed slurry composition is preferably within the range because the inorganic fine particle-dispersed slurry composition contains a component having a low polymerization degree appropriately, and the productivity can be improved. In addition, the sheet strength of the obtained inorganic fine particle-dispersed sheet can be made moderate. Further, the surface smoothness of the obtained ceramic green sheet can be sufficiently improved.

The Mw/Mn is more preferably 3 or more, and still more preferably 6 or less.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) are average molecular weights based on polystyrene conversion, and can be obtained by GPC measurement using, for example, a column LF-804 (manufactured by Showa electric company) as a column.

The OH group content in the high molecular weight (meth) acrylic resin (A) is 0.4 wt% or more and 2.0 wt% or less.

By setting the range as described above, the binder resin can exhibit very excellent decomposability even at low temperatures, and can also improve the dispersibility of the inorganic fine particles and the aggregation-inhibiting effect.

The OH group concentration is preferably 0.5 wt% or more, more preferably 0.6 wt% or more, and preferably 1.6 wt% or less, more preferably 1.4 wt% or less.

The weight concentration of the OH group is a ratio of the weight of the OH group to the weight of the entire high molecular weight (meth) acrylic resin (a), and can be calculated based on the following formula.

The weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin (a) = [ weight of OH groups contained in all monomers/(weight of all monomers+weight of polymerization initiator) ]×100

< high molecular weight (meth) acrylic resin (B) >)

In the (meth) acrylic resin composition of the present invention satisfying the above (2), the (meth) acrylic resin contains a high molecular weight (meth) acrylic resin (B).

The weight average molecular weight of the high molecular weight (meth) acrylic resin (a) exceeds 30 ten thousand and is 50 ten thousand or less.

The weight average molecular weight is preferably 32 ten thousand or more, more preferably 33 ten thousand or more, preferably 48 ten thousand or less, more preferably 45 ten thousand or less.

The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the high molecular weight (meth) acrylic resin (B) is preferably 2 or more, more preferably 8 or less.

When the viscosity is within the above range, the viscosity of the inorganic fine particle-dispersed slurry composition is preferably within the range because the composition contains a component having a low degree of polymerization appropriately, and the productivity can be improved. In addition, the sheet strength of the obtained inorganic fine particle-dispersed sheet can be made moderate. Further, the surface smoothness of the obtained ceramic green sheet can be sufficiently improved.

The Mw/Mn is more preferably 3 or more, and still more preferably 6 or less.

The OH group content in the high molecular weight (meth) acrylic resin (B) is 1.3 wt% or more and 3.5 wt% or less.

By setting the range as described above, the binder resin can exhibit very excellent decomposability even at low temperatures, and can also improve the dispersibility of the inorganic fine particles and the aggregation inhibition effect.

The OH group concentration is preferably 1.5 wt% or more, more preferably 2 wt% or more, and preferably 3.3 wt% or less, more preferably 3 wt% or less.

The weight concentration of the OH group is a ratio of the weight of the OH group to the weight of the entire high molecular weight (meth) acrylic resin (B), and can be calculated based on the following formula.

The weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin (B) = [ weight of OH groups contained in all monomers/(weight of all monomers+weight of polymerization initiator) ]×100

The high molecular weight (meth) acrylic resins (a) and (B) preferably have structural units represented by the following formula (a), and more preferably have structural units represented by the following formula (B).

[ chemical formula 2]

As R as above ¹ More preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, and isobutyl.

As R as above ² A linear or branched alkyl group having 2 to 4 carbon atoms, in which at least 1 of the hydrogen atoms is substituted with an OH group, is preferable, and examples thereof include: 2-hydroxyethyl, 2-hydroxypropyl, 2-hydroxybutyl, and the like.

The content of the structural unit represented by the formula (a) in the high molecular weight (meth) acrylic resins (a) and (B) is preferably 79% by weight or more, and more preferably 96% by weight or less.

By setting the range as described above, the low-temperature decomposability can be sufficiently improved.

The content of the structural unit represented by the formula (a) is more preferably 85% by weight or more, and still more preferably 95% by weight or less.

The content of the structural unit represented by the formula (B) in the high molecular weight (meth) acrylic resins (a) and (B) is preferably 3.1% by weight or more, and more preferably 17% by weight or less.

As a solvent for the binder resin, ethanol is often used, but usually, the solubility of the acrylic resin in ethanol is lower than that of the polyvinyl acetal resin, and if the acrylic resin is added after one crushing, there is a problem that inorganic fine particles agglomerate, but by setting the above range, the dispersibility of the inorganic fine particles and the agglomeration suppressing effect can be improved.

In addition, the solubility in ethanol can be further improved.

The content of the structural unit represented by the above formula (2) is more preferably 4% by weight or more, and still more preferably 15% by weight or less.

The high molecular weight (meth) acrylic resins (a) and (B) preferably have segments derived from (meth) acrylic esters having a linear or branched alkyl group having 3 to 4 carbon atoms.

By having the segment, the low-temperature decomposability can be further improved.

Examples of the (meth) acrylate having a linear or branched alkyl group having 3 to 4 carbon atoms include: n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and the like. Among them, isobutyl (meth) acrylate is preferable.

In the high molecular weight (meth) acrylic resins (a) and (B), the content of the segment derived from the (meth) acrylic acid ester having a linear or branched alkyl group having 3 to 4 carbon atoms is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 95% by weight or less, and still more preferably 88% by weight or less.

The high molecular weight (meth) acrylic resins (a) and (B) may have segments derived from (meth) acrylic esters having an alkyl group having 1 to 2 carbon atoms.

Examples of the (meth) acrylic acid ester having an alkyl group having 1 to 2 carbon atoms include methyl (meth) acrylate and ethyl (meth) acrylate.

The content of the segment derived from the (meth) acrylic acid ester having an alkyl group having 1 to 2 carbon atoms in the high molecular weight (meth) acrylic resins (a) and (B) is preferably 0% by weight or more, more preferably 10% by weight or more, preferably 66.8% by weight or less, and still more preferably 46% by weight or less.

The high molecular weight (meth) acrylic resins (a) and (B) may have segments derived from (meth) acrylic esters having a linear or branched alkyl group having 5 to 8 carbon atoms.

Examples of the (meth) acrylic acid ester having a linear or branched alkyl group having 5 to 8 carbon atoms include n-pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Among them, preferred is a (meth) acrylic acid ester having a linear or branched alkyl group having 6 to 8 carbon atoms, and more preferred is 2-ethylhexyl (meth) acrylate.

In the high molecular weight (meth) acrylic resins (a) and (B), the content of the segment derived from the (meth) acrylic acid ester having a linear or branched alkyl group having 5 to 8 carbon atoms is preferably 0% by weight or more, more preferably 9% by weight or more, preferably 25% by weight or less, and still more preferably 20% by weight or less.

The high molecular weight (meth) acrylic resins (a) and (B) may have segments derived from (meth) acrylic esters having a linear or branched alkyl group having 9 or more carbon atoms.

Examples of the (meth) acrylate having a linear or branched alkyl group having 9 or more carbon atoms include: n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-lauryl (meth) acrylate, iso-lauryl (meth) acrylate, n-stearyl (meth) acrylate, isostearyl (meth) acrylate, and the like.

The high molecular weight (meth) acrylic resins (a) and (B) preferably have segments derived from (meth) acrylic esters having at least 1 linear or branched alkyl group substituted with an OH group in a hydrogen atom.

By having the segment, the binder resin can exhibit very excellent decomposability even at low temperatures, and can also improve the dispersibility of inorganic fine particles and the aggregation-inhibiting effect.

The (meth) acrylate having a linear or branched alkyl group in which at least 1 of the hydrogen atoms is replaced with an OH group is preferably a (meth) acrylate having a weight ratio of the OH group of 10.5% by weight or more, more preferably a (meth) acrylate having a weight ratio of 11.5% by weight or more, and still more preferably a (meth) acrylate having a weight ratio of 13.1% by weight or less.

The high molecular weight (meth) acrylic resins (a) and (B) are preferably segments derived from (meth) acrylic esters having a linear or branched alkyl group having 2 to 4 carbon atoms, at least 1 of which is substituted with an OH group, in the hydrogen atoms.

Examples of the (meth) acrylate having a linear or branched alkyl group having 2 to 4 carbon atoms, at least 1 of which is substituted with an OH group, include: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like. Among them, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate are preferable.

In the high molecular weight (meth) acrylic resins (a) and (B), the content of the segment derived from the (meth) acrylic acid ester having a linear or branched alkyl group having 2 to 4 carbon atoms in which at least 1 of the hydrogen atoms is replaced with an OH group is preferably 3.1% by weight or more, more preferably 5.0% by weight or more, preferably 17.0% by weight or less, and still more preferably 12.2% by weight or less.

The high molecular weight (meth) acrylic resins (a) and (B) are preferably segments derived from (meth) acrylic esters having a linear or branched alkyl group having 5 or more carbon atoms, at least 1 of which is replaced with an OH group in a hydrogen atom.

Examples of the (meth) acrylate having a linear or branched alkyl group having 5 or more carbon atoms, at least 1 of which is substituted with an OH group, include: hydroxy amyl (meth) acrylate, hydroxy hexyl (meth) acrylate, hydroxy heptyl (meth) acrylate, hydroxy octyl (meth) acrylate, and the like.

The high molecular weight (meth) acrylic resins (a) and (B) may have, in addition to the segments derived from the (meth) acrylic esters, segments derived from (meth) acrylic acid, segments derived from other (meth) acrylic esters such as (meth) acrylic esters having glycidyl groups, and the like.

The glass transition temperatures (Tg) of the high molecular weight (meth) acrylic resins (A) and (B) are preferably 30℃to 85 ℃.

By setting the amount in the above range, the amount of plasticizer added can be reduced, and the low-temperature decomposability can be improved.

The Tg is more preferably 32 ℃ or higher, still more preferably 42 ℃ or higher, still more preferably 45 ℃ or higher, particularly preferably 50 ℃ or higher, still more preferably 80 ℃ or lower, still more preferably 75 ℃ or lower.

The glass transition temperature (Tg) may be measured using, for example, a Differential Scanning Calorimeter (DSC).

The solubility of the high molecular weight (meth) acrylic resins (a) and (B) in ethanol is preferably 10 parts by weight or more per 100 parts by weight of ethanol.

By setting the range as described above, the dispersibility of the inorganic fine particles and the aggregation inhibition effect can be improved. In addition, the solubility in an organic solvent can be sufficiently improved.

The solubility in ethanol is more preferably 50 parts by weight or more, and still more preferably 100 parts by weight or more.

The solubility in ethanol refers to the amount of resin added until a precipitate is formed when the resin is dissolved in 100 parts by weight of ethanol at 25 ℃.

The content of the high molecular weight (meth) acrylic resin (a) in the (meth) acrylic resin composition of the present invention is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 30% by weight or more, preferably 70% by weight or less, and still more preferably 60% by weight or less.

The content of the high molecular weight (meth) acrylic resin (B) in the (meth) acrylic resin composition of the present invention is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 30% by weight or more, preferably 70% by weight or less, and still more preferably 60% by weight or less.

In the (meth) acrylic resin composition of the present invention satisfying the above (2), the weight concentration of the S atom contained in the (meth) acrylic resin is preferably 250ppm or more, and more preferably 20000ppm or less.

The weight concentration of the S atom is more preferably 400ppm or more, and still more preferably 15000ppm or less.

The weight concentration of the S atom means a ratio of the weight of the S atom to the weight of the (meth) acrylic resin, and can be calculated based on the following formula.

The weight concentration of the S atom contained in the (meth) acrylic resin= [ weight of the S atom contained in the chain transfer agent/(weight of all monomers+weight of polymerization initiator+weight of chain transfer agent) ]×100

When the (meth) acrylic resin composition contains a plurality of types of (meth) acrylic resins, the weight concentration of the S atom can be calculated based on the weight concentration of the S atom contained in each (meth) acrylic resin and the blending ratio of each (meth) acrylic resin.

The weight concentration of the S atoms may be obtained by ICP-AES (inductively coupled plasma emission spectrometry).

The method for producing the high molecular weight (meth) acrylic resins (a) and (B) is not particularly limited. For example, there may be mentioned: and a method in which an organic solvent or the like is added to a raw material monomer mixture containing (meth) acrylic acid ester or the like to prepare a monomer mixture, and a polymerization initiator and a chain transfer agent are further added to the monomer mixture to copolymerize the raw material monomers.

The method for polymerizing is not particularly limited, and examples thereof include emulsion polymerization, suspension polymerization, bulk polymerization, interfacial polymerization, solution polymerization, and the like. Among them, solution polymerization is preferable.

Examples of the polymerization initiator include: tert-butyl peroxypivalate, p-menthane hydroperoxide, dicumyl peroxide, 1, 3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, tert-butyl hydroperoxide, cyclohexanone peroxide, disuccinic acid peroxide, and the like.

Examples of the chain transfer agent include: 3-mercapto-1, 2-propanediol, 3-mercapto-1-propanol, 3-mercapto-2-butanol, 8-mercapto-1-octanol, mercaptosuccinic acid, mercaptoacetic acid, and the like.

< Low molecular weight (meth) acrylic resin (C) >)

In the (meth) acrylic resin composition of the present invention satisfying the above (3), the (meth) acrylic resin contains a low molecular weight (meth) acrylic resin (C).

In the present specification, the weight average molecular weight of the low molecular weight (meth) acrylic resin (C) is 0.5 to 10 tens of thousands.

By containing the low molecular weight (meth) acrylic resin (C), the dispersibility of the inorganic fine particles can be improved.

The weight average molecular weight is more preferably 0.6 ten thousand or more, still more preferably 0.8 ten thousand or more, still more preferably 9 ten thousand or less, still more preferably 3 ten thousand or less.

The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the low molecular weight (meth) acrylic resin (C) is preferably 1.3 or more, more preferably 2 or more, and still more preferably 8 or less.

When the viscosity is within the above range, the inorganic fine particle-dispersed slurry composition preferably has a viscosity in a range where the composition has a low polymerization degree, and thus the productivity can be improved. In addition, the sheet strength of the obtained inorganic fine particle-dispersed sheet can be made moderate. Further, the surface smoothness of the obtained ceramic green sheet can be sufficiently improved.

The Mw/Mn is more preferably 3 or more, and still more preferably 6 or less.

The concentration of OH groups contained in the low molecular weight (meth) acrylic resin (C) is 1.3 wt% or more and 3.5 wt% or less.

The concentration of the OH groups is preferably 1.4 wt% or more, more preferably 3.3 wt% or less, and still more preferably 3.2 wt% or less.

The weight concentration of the OH group is a ratio of the weight of the OH group to the weight of the whole low molecular weight (meth) acrylic resin (C), and can be calculated based on the following formula.

The weight concentration of OH groups contained in the low molecular weight (meth) acrylic resin (C) = [ (weight of OH groups contained in all monomers+weight of OH groups contained in chain transfer agent)/(weight of all monomers+weight of polymerization initiator+weight of chain transfer agent) ]100

The low molecular weight (meth) acrylic resin (C) preferably has a segment derived from a (meth) acrylate having a linear or branched alkyl group having 3 to 4 carbon atoms.

The content of the segment derived from the (meth) acrylic acid ester having a linear or branched alkyl group having 3 to 4 carbon atoms in the low molecular weight (meth) acrylic resin (C) is preferably 38% by weight or more, more preferably 50% by weight or more, preferably 80% by weight or less, more preferably 75% by weight or less.

The low molecular weight (meth) acrylic resin (C) may have a segment derived from a (meth) acrylate having an alkyl group having 1 to 2 carbon atoms.

The content of the segment derived from the (meth) acrylic acid ester having an alkyl group having 1 to 2 carbon atoms in the low molecular weight (meth) acrylic resin (C) is preferably 0% by weight or more, more preferably 7% by weight or more, preferably 33% by weight or less, more preferably 20.5% by weight or less.

The low molecular weight (meth) acrylic resin (C) may have a segment derived from a (meth) acrylic acid ester having a linear or branched alkyl group having 5 to 8 carbon atoms.

The content of the segment derived from the (meth) acrylic acid ester having a linear or branched alkyl group having 5 to 8 carbon atoms in the low molecular weight (meth) acrylic resin (C) is preferably 0% by weight or more, more preferably 10% by weight or more, preferably 40% by weight or less, more preferably 30% by weight or less.

The low molecular weight (meth) acrylic resin (C) may have a segment derived from a (meth) acrylic acid ester having a linear or branched alkyl group having 9 or more carbon atoms.

The low molecular weight (meth) acrylic resin (C) preferably has a segment derived from a (meth) acrylic acid ester having at least 1 linear or branched alkyl group substituted with an OH group in a hydrogen atom.

The low molecular weight (meth) acrylic resin (C) preferably has a segment derived from a (meth) acrylic acid ester having a linear or branched alkyl group having 2 to 4 carbon atoms, at least 1 of which is substituted with an OH group in a hydrogen atom.

In the low molecular weight (meth) acrylic resin (C), the content of the segment derived from the (meth) acrylic acid ester having a linear or branched alkyl group having 2 to 4 carbon atoms, at least 1 of which is substituted with an OH group, is preferably 7% by weight or more, more preferably 10% by weight or more, preferably 20% by weight or less, and still more preferably 16% by weight or less.

The low molecular weight (meth) acrylic resin (C) preferably has a segment derived from a (meth) acrylic acid ester having a linear or branched alkyl group having 5 or more carbon atoms, at least 1 of which is substituted with an OH group in a hydrogen atom.

The low molecular weight (meth) acrylic resin (C) may have a segment derived from (meth) acrylic acid, a segment derived from (meth) acrylic acid ester having a glycidyl group, or another (meth) acrylic acid ester, in addition to the segment derived from (meth) acrylic acid ester.

In the (meth) acrylic resin composition of the present invention satisfying the above (3), the weight concentration of the S atom contained in the (meth) acrylic resin is 250ppm to 20000 ppm.

The weight concentration of the S atom is preferably 1500ppm or more, more preferably 3000ppm or more, preferably 18000ppm or less, more preferably 10000ppm or less.

The glass transition temperature (Tg) of the low molecular weight (meth) acrylic resin (C) is 30-60 ℃.

The Tg is preferably 32℃or higher, more preferably 42℃or higher, still more preferably 45℃or higher, preferably 58℃or lower, still more preferably 50℃or lower.

In the (meth) acrylic resin composition of the present invention, the content of the low molecular weight (meth) acrylic resin (C) is preferably 0.006 wt% or more, more preferably 0.01 wt% or more, preferably 10 wt% or less, more preferably 8 wt% or less.

In the (meth) acrylic resin composition of the present invention satisfying the above (1), it is preferable that the (meth) acrylic resin further contains the low molecular weight (meth) acrylic resin (B) in addition to the high molecular weight (meth) acrylic resin (a).

Further, by containing the low molecular weight (meth) acrylic resin (C), the dispersibility of the inorganic fine particles can be further improved.

In the (meth) acrylic resin composition of the present invention satisfying the above (1), the content of the low molecular weight (meth) acrylic resin (C) is preferably 0.1 parts by weight or more, and more preferably 10 parts by weight or less, based on 100 parts by weight of the high molecular weight (meth) acrylic resin (a).

By setting the range as described above, the dispersibility of the inorganic fine particles can be further improved.

The content of the low molecular weight (meth) acrylic resin (C) is more preferably 0.3 parts by weight or more, and still more preferably 7.5 parts by weight or less, based on 100 parts by weight of the high molecular weight (meth) acrylic resin.

The method for producing the low molecular weight (meth) acrylic resin (C) is not particularly limited. For example, there may be mentioned: and a method in which an organic solvent or the like is added to a raw material monomer mixture containing (meth) acrylic acid ester or the like to prepare a monomer mixture, and a polymerization initiator and a chain transfer agent are further added to the monomer mixture to copolymerize the raw material monomers.

< organic solvent >)

The (meth) acrylic resin composition of the present invention contains an organic solvent.

The concentration of OH groups contained in the organic solvent is 9.0 wt% or more and 28.0 wt% or less.

By containing the organic solvent, the dispersibility and aggregation inhibition effect of the inorganic fine particles can be improved.

The OH group concentration is preferably 11.0 wt% or more, more preferably 13.0 wt% or more, preferably 26.0 wt% or less, more preferably 24 wt% or less, and further preferably 22.5 wt% or less.

The weight concentration of the OH group is a ratio of the weight of the OH group to the weight of the entire organic solvent, and can be calculated based on the following formula.

The weight concentration of OH groups contained in the organic solvent= (weight of OH groups contained in all organic solvents/weight of all organic solvents) ×100

The ratio of the weight concentration of OH groups contained in the organic solvent to the weight concentration of OH groups contained in the high molecular weight (meth) acrylic resins (a) and (B) (the weight concentration of OH groups contained in the organic solvent/the weight concentration of OH groups contained in the high molecular weight (meth) acrylic resins) is preferably 4.5 or more, and preferably 46.2 or less.

By setting the range as described above, the dispersibility of the inorganic fine particles and the aggregation inhibition effect can be further improved.

The above ratio is more preferably 8.1 or more, still more preferably 10 or more, still more preferably 40 or less, still more preferably 30 or less, still more preferably 25 or less, and particularly preferably 20 or less.

The organic solvent contains an organic solvent having an OH group.

Examples of the organic solvent having an OH group include: aliphatic alcohols, cyclic alcohols, alicyclic alcohols, and the like.

Examples of the aliphatic alcohol include: ethanol, propanol, isopropanol, heptanol, octanol, decanol, tridecanol, lauryl alcohol, tetradecanol, cetyl alcohol, 2-ethyl-1-hexanol, stearyl alcohol, cetyl alcohol, oleyl alcohol, TEXANOL, 2-butyl-2-ethyl-1, 3-propanediol, neopentyl glycol, and the like.

Examples of the cyclic alcohol include: cresols, eugenol, and the like.

Examples of the alicyclic alcohol include: and cycloalkanols such as cyclohexanol, terpene alcohols such as terpineol and dihydroterpineol.

Among them, aliphatic alcohols are preferable, and ethanol, isopropanol, 2-butyl-2-ethyl-1, 3-propanediol, neopentyl glycol, and TEXANOL are preferable.

The molecular weight of the organic solvent having an OH group is preferably 46 or more, more preferably 60 or more, preferably 220 or less, more preferably 160 or less.

The number of carbon atoms of the organic solvent having an OH group is preferably 2 or more, more preferably 3 or more, and preferably 12 or less, more preferably 10 or less.

The proportion of the weight of the OH group contained in the organic solvent having an OH group is preferably 7.5% by weight or more, more preferably 15% by weight or more, still more preferably 21% by weight or more, and still more preferably 37% by weight or less.

The content of the organic solvent having an OH group is preferably 29% by weight or more, more preferably 43% by weight or more, preferably 79% by weight or less, more preferably 61% by weight or less, based on the entire organic solvent.

The organic solvent may contain an organic solvent other than the organic solvent having an OH group.

Examples of the other organic solvents include: ketones such as acetone, methyl ethyl ketone, diacetone, and diisobutyl ketone, aromatic hydrocarbons such as toluene and xylene, esters such as methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, methyl valerate, ethyl valerate, butyl valerate, methyl caproate, ethyl caproate, butyl caproate, ethyl acetate, butyl acetate, hexyl acetate, 2-ethylhexyl acetate, and 2-ethylhexyl butyrate.

Among them, toluene, butyl acetate, methyl ethyl ketone are preferable.

The content of the other organic solvent is preferably 21 wt% or more, more preferably 39 wt% or more, preferably 71 wt% or less, more preferably 57 wt% or less, based on the entire organic solvent.

The content of the organic solvent in the (meth) acrylic resin composition of the present invention is preferably 20 wt% or more, more preferably 30 wt% or more, preferably 95 wt% or less, more preferably 70 wt% or less, and further preferably 60 wt% or less.

The content of the organic solvent in the (meth) acrylic resin composition of the present invention is preferably 25 parts by weight or more, more preferably 100 parts by weight or more, preferably 2000 parts by weight or less, more preferably 1500 parts by weight or less, based on 100 parts by weight of the (meth) acrylic resin.

The content of the organic solvent in the (meth) acrylic resin composition of the present invention is preferably 25 parts by weight or more, more preferably 42.9 parts by weight or more, preferably 1900 parts by weight or less, more preferably 233.3 parts by weight or less, and still more preferably 150 parts by weight or less, based on 100 parts by weight of the high molecular weight (meth) acrylic resin (a).

The content of the organic solvent in the (meth) acrylic resin composition of the present invention is preferably 25 parts by weight or more, more preferably 100 parts by weight or more, preferably 2000 parts by weight or less, more preferably 1500 parts by weight or less, based on 100 parts by weight of the high molecular weight (meth) acrylic resin (B).

The content of the organic solvent in the (meth) acrylic resin composition of the present invention is preferably 25 parts by weight or more, more preferably 1000 parts by weight or more, preferably 1500000 parts by weight or less, more preferably 1000000 parts by weight or less, based on 100 parts by weight of the low molecular weight (meth) acrylic resin (C).

The boiling point of the organic solvent is preferably 90 to 160 ℃. By setting the boiling point to 90 ℃ or higher, premature vaporization is prevented, and the handleability is excellent. The strength of the inorganic fine particle-dispersed sheet can be improved by setting the boiling point to 160 ℃ or lower.

The method for producing the (meth) acrylic resin composition of the present invention is not particularly limited, and examples thereof include: a method of mixing a (meth) acrylic resin containing at least 1 of the high molecular weight (meth) acrylic resin (a), the high molecular weight (meth) acrylic resin (B), and the high molecular weight (meth) acrylic resin (C), the organic solvent, and other additives, if necessary.

The (meth) acrylic resin composition of the present invention is excellent in low-temperature decomposability, and also excellent in dispersibility of inorganic fine particles and aggregation-inhibiting effect, and therefore, can be suitably used as an inorganic fine particle-dispersed slurry composition by combining inorganic fine particles with a plasticizer.

The inorganic fine particle-dispersed slurry composition containing the (meth) acrylic resin composition of the present invention, inorganic fine particles and plasticizer is also one of the present invention.

< inorganic particles >)

The inorganic fine particle-dispersed slurry composition of the present invention contains inorganic fine particles.

The inorganic fine particles are not particularly limited, and examples thereof include: glass powder, ceramic powder, phosphor particles, silicon oxide, etc., metal particles, etc.

The glass powder is not particularly limited, and examples thereof include: glass powder such as bismuth oxide glass, silicate glass, lead glass, zinc glass, boron glass, etc., caO-Al ₂ O ₃ -SiO ₂ Of MgO-Al system ₂ O ₃ -SiO ₂ Tied, liO ₂ -Al ₂ O ₃ -SiO ₂ Glass powder of various silicon oxides, etc.

Further, as the glass powder, snO-B may be used ₂ O ₃ -P ₂ O ₅ -Al ₂ O ₃ Mixtures, pbO-B ₂ O ₃ -SiO ₂ Mixtures, baO-ZnO-B ₂ O ₃ -SiO ₂ Mixture, znO-Bi ₂ O ₃ -B ₂ O ₃ -SiO ₂ Mixtures, bi ₂ O ₃ -B ₂ O ₃ BaO-CuO mixture, bi ₂ O ₃ -ZnO-B ₂ O ₃ -Al ₂ O ₃ -SrO mixture, znO-Bi ₂ O ₃ -B ₂ O ₃ Mixtures, bi ₂ O ₃ -SiO ₂ Mixtures, P ₂ O ₅ -Na ₂ O-CaO-BaO-Al ₂ O ₃ -B ₂ O ₃ Mixtures, P ₂ O ₅ Mixtures of SnO, P ₂ O ₅ -SnO-B ₂ O ₃ Mixtures, P ₂ O ₅ -SnO-SiO ₂ Mixture, cuO-P ₂ O ₅ RO mixture, siO ₂ -B ₂ O ₃ -ZnO-Na ₂ O-Li ₂ O-NaF-V ₂ O ₅ Mixtures, P ₂ O ₅ -ZnO-SnO-R ₂ O-RO mixture, B ₂ O ₃ -SiO ₂ ZnO mixture, B ₂ O ₃ -SiO ₂ -Al ₂ O ₃ -ZrO ₂ Mixtures, siO ₂ -B ₂ O ₃ -ZnO-R ₂ O-RO mixture, siO ₂ -B ₂ O ₃ -Al ₂ O ₃ -RO-R ₂ O mixture, srO-ZnO-P ₂ O ₅ Mixtures, srO-ZnO-P ₂ O ₅ Mixtures, baO-ZnO-B ₂ O ₃ -SiO ₂ Glass powder such as mixture. R is an element selected from Zn, ba, ca, mg, sr, sn, ni, fe and Mn.

PbO-B is particularly preferred ₂ O ₃ -SiO ₂ Glass powder of mixture, and BaO-ZnO-B containing no lead ₂ O ₃ -SiO ₂ Mixtures or ZnO-Bi ₂ O ₃ -B ₂ O ₃ -SiO ₂ Mixtures, etc.

The ceramic powder is not particularly limited, and examples thereof include: aluminum oxide, ferrite, zirconium oxide, zircon, barium zirconate, calcium zirconate, titanium oxide, barium titanate, strontium titanate, calcium titanate, magnesium titanate, zinc titanate, lanthanum titanate, neodymium titanate, lead zirconate titanate (japanese コ), aluminum nitride (japanese choking), silicon nitride, boron carbide, barium stannate, calcium stannate, magnesium silicate, mullite, steatite, cordierite, forsterite, and the like.

Further, ITO, FTO, niobium oxide, vanadium oxide, tungsten oxide, lanthanum strontium manganate, yttrium stabilized zirconia, gadolinium doped ceria, nickel oxide, lanthanum chromate, or the like may be used.

The phosphor fine particles are not particularly limited, and for example, a blue phosphor, a red phosphor, a green phosphor, or the like known as a phosphor for a display can be used as the phosphor. As the blue phosphor material, mgAl, for example, can be used ₁₀ O ₁₇ ：Eu、Y ₂ SiO ₅ : ce-based CaWO ₄ : pb-based BaMgAl ₁₄ O ₂₃ : eu and BaMgAl systems ₁₆ O ₂₇ : eu and BaMg series ₂ Al ₁₄ O ₂₃ : eu and BaMg series ₂ Al ₁₄ O ₂₇ : eu-series, znS: (Ag, cd) -based substances. As the red phosphor material, Y can be used, for example ₂ O ₃ : eu series, Y ₂ SiO ₅ : eu series, Y ₃ Al ₅ O ₁₂ : eu and Zn system ₃ (PO ₄ ) ₂ : mn series, YBO ₃ : eu system, (Y, gd) BO ₃ : eu system, gdBO ₃ : eu series, scBO ₃ : eu system,LuBO ₃ : eu-based materials. As the green phosphor material, zn can be used, for example ₂ SiO ₄ : mn-based BaAl-based alloy ₁₂ O ₁₉ : mn-based, srAl-based ₁₃ O ₁₉ : mn series, caAl ₁₂ O ₁₉ : mn series, YBO ₃ : tb series, baMgAl ₁₄ O ₂₃ : mn series, luBO ₃ : tb series, gdBO ₃ : tb series, scBO ₃ : tb series, sr6Si ₃ O ₃ Cl ₄ : eu-based materials. In addition, znO may also be used: zn system, znS: (Cu, al) system, znS: ag and Y series ₂ O ₂ S: eu-series, znS: zn-based, (Y, cd) BO ₃ : eu and BaMgAl systems ₁₂ O ₂₃ : eu-based materials.

The metal fine particles are not particularly limited, and examples thereof include: powders containing iron, copper, nickel, palladium, platinum, gold, silver, aluminum, tungsten, alloys thereof, or the like.

In addition, metals such as copper and iron which have good adsorption properties with carboxyl groups, amino groups, amide groups and the like and are easily oxidized can be preferably used. These metal powders may be used alone or in combination of 2 or more.

In addition to the metal complex, various carbon blacks, carbon nanotubes, and the like can be used for the metal fine particles.

The inorganic fine particles preferably contain lithium or titanium. Specifically, for example, there may be mentioned: liO (LiO) ₂ ·Al ₂ O ₃ ·SiO ₂ Low melting point glass such as inorganic glass, li ₂ S-M _x S _y Lithium sulfur glass such as (m= B, si, ge, P), liCeO ₂ Equal lithium cobalt composite oxide, liMnO ₄ Isolithium manganese composite oxide, lithium nickel composite oxide, lithium vanadium composite oxide, lithium zirconium composite oxide, lithium hafnium composite oxide, and lithium silicophosphate (Li) _3.5 Si _0.5 P _0.5 O ₄ ) Lithium titanium phosphate (LiTi) ₂ (PO ₄ ) ₃ ) Lithium titanate (Li) ₄ Ti ₅ O ₁₂ )、Li _4/3 Ti _5/ ₃ O ₄ 、LiCoO ₂ Lithium germanium phosphate (LiGe) ₂ (PO ₄ ) ₃ )、Li ₂ SiS glass, li ₄ GeS ₄ -Li ₃ PS ₄ Glass, liSiO ₃ 、LiMn ₂ O ₄ 、Li ₂ S-P ₂ S ₅ Glass ceramic, li ₂ O-SiO ₂ 、Li ₂ O-V ₂ O ₅ -SiO ₂ 、LiS-SiS ₂ -Li ₄ SiO ₄ Glass, liPON plasma conductive oxide, and Li ₂ O-P ₂ O ₅ -B ₂ O ₃ 、Li ₂ O-GeO ₂ Lithium oxide compound such as Ba and Li _x Al _y Ti _z (PO ₄ ) ₃ Glass of La _x Li _y TiO _z Glass of Li _x Ge _y P _z O ₄ Glass of Li ₇ La ₃ Zr ₂ O ₁₂ Glass of Li _v Si _w P _x S _y Cl _z Glass, liNbO ₃ Lithium-alumina compounds such as lithium niobium oxide and Li-beta-alumina, and Li ₁₄ Zn(GeO ₄ ) ₄ And lithium zinc oxide.

The content of the inorganic fine particles in the inorganic fine particle-dispersed slurry composition of the present invention is not particularly limited, but is preferably 10% by weight at the lower limit and 90% by weight at the upper limit. When the content is 10% by weight or more, the coating composition can have a sufficient viscosity and excellent coating properties, and when the content is 90% by weight or less, the dispersibility of the inorganic fine particles can be excellent.

< others >

The inorganic fine particle-dispersed slurry composition of the present invention further contains a plasticizer.

Examples of the plasticizer include: di (butoxyethyl) adipate, dibutoxyethoxyethyl adipate, triethylethylene glycol dibutyl ether, triethyleneglycol bis (2-ethylhexanoate), triethyleneglycol dihexanoate, acetyltriethyl citrate, acetyltributyl citrate, acetyldiethyl citrate, acetyldibutyl citrate, dibutyl sebacate, triacetin, diethyl acetoxymalonate, diethyl ethoxymalonate, and the like.

By using these plasticizers, the amount of plasticizer added can be reduced (when about 30 wt% is added to the adhesive, it can be reduced to 25 wt% or less, and further, it can be reduced to 20 wt% or less) as compared with the case of using a normal plasticizer.

Among them, a non-aromatic plasticizer having no aromatic ring such as benzene ring in the structure is preferably used, and a component derived from adipic acid, triethylene glycol, citric acid or succinic acid is more preferably contained. It is not preferable that the plasticizer having an aromatic ring is burned to be easily soot.

The plasticizer is preferably a plasticizer having an alkyl group having 2 or more carbon atoms such as an ethyl group and a butyl group, and more preferably a plasticizer having an alkyl group having 4 or more carbon atoms.

The plasticizer can suppress absorption of moisture by the plasticizer by containing an alkyl group having 2 or more carbon atoms, and prevent the resulting inorganic fine particle-dispersed sheet from causing defects such as voids and swelling. It is particularly preferred that the alkyl groups of the plasticizer are located at the molecular terminals.

The plasticizer preferably has a functional group having 2 carbon atoms such as ethyl, a functional group having 4 carbon atoms such as butyl, and a functional group such as butoxyethyl. The above functional groups are preferably present in the terminal molecular chain.

The plasticizer having a functional group having 2 carbon atoms such as ethyl group in the terminal molecular chain has good suitability for a segment derived from ethyl methacrylate (Japanese: phase), and the plasticizer having a functional group having 4 carbon atoms such as butyl group in the terminal molecule has good suitability for a segment derived from butyl methacrylate. The plasticizer having a functional group having 2 or 4 carbon atoms is excellent in suitability for the high molecular weight (meth) acrylic resin of the present invention, and the brittleness of the resin can be preferably improved. The butoxyethyl group is preferably used because of its excellent suitability for the composition of both the segment derived from ethyl methacrylate and the segment derived from butyl methacrylate.

Carbon of the plasticizer: the oxygen ratio is preferably 5:1 to 3:1.

by causing carbon to: the oxygen ratio in the above range can improve combustibility of the plasticizer and prevent the generation of residual carbon. In addition, the compatibility with (meth) acrylic resins can be improved, and plasticizing effects can be exhibited even in a small amount of plasticizer.

The high boiling point organic solvents of propylene glycol skeleton and trimethylene glycol skeleton may contain an alkyl group having 4 or more carbon atoms and carbon: oxygen ratio of 5:1 to 3:1, it can be preferably used.

The boiling point of the plasticizer is preferably 240 ℃ or higher and less than 390 ℃. By setting the boiling point to 240 ℃ or higher, the mixture is easily evaporated in the drying step, and thus, the mixture can be prevented from remaining in the molded article. In addition, by making it less than 390 ℃, the generation of residual carbon can be prevented. The boiling point refers to a boiling point at normal pressure.

The content of the plasticizer in the inorganic fine particle-dispersed slurry composition of the present invention is not particularly limited, but the lower limit is preferably 0.1 wt% and the upper limit is preferably 3.0 wt%. By setting the range to the above range, the firing residue of the plasticizer can be reduced.

The content of the (meth) acrylic resin composition in the inorganic fine particle-dispersed slurry composition of the present invention is not particularly limited, but the lower limit is preferably 0.5% by weight, and the upper limit is preferably 10% by weight.

By setting the range as described above, the inorganic fine particle-dispersed slurry composition can be degreased even when fired at a low temperature, and can be produced with excellent dispersibility of inorganic fine particles and excellent aggregation-inhibiting effect.

The content of the (meth) acrylic resin composition is more preferably 1% by weight at the lower limit and 7% by weight at the upper limit.

The inorganic fine particle-dispersed slurry composition of the present invention may further contain an additive such as a surfactant.

The surfactant is not particularly limited, and examples thereof include: cationic surfactants, anionic surfactants, and nonionic surfactants.

The nonionic surfactant is not particularly limited, but is preferably a nonionic surfactant having an HLB value of 10 or more and 20 or less. Here, the HLB value is used as an index indicating hydrophilicity and lipophilicity of the surfactant, and several calculation methods are proposed, for example, there are definitions such as the following: the saponification value of the ester-based surfactant was S, the acid value of the fatty acid constituting the surfactant was A, and the HLB value was 20 (1-S/A). Specifically, nonionic surfactants having polyethylene oxide in which an alkylene ether is added to a fatty chain are preferable, and specifically, for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether and the like are preferably used. The nonionic surfactant has good thermal decomposability, but if added in a large amount, the inorganic fine particle-dispersed slurry composition may have reduced thermal decomposability, so that the preferable upper limit of the content is 5% by weight.

The viscosity of the inorganic fine particle-dispersed slurry composition of the present invention is not particularly limited, but the preferable lower limit of the viscosity is 0.1pa·s, and the preferable upper limit is 100pa·s when measured at 20 ℃ using a type B viscometer with the probe rotation speed set to 5 rpm.

By setting the viscosity to 0.1pa·s or more, the obtained inorganic fine particle-dispersed sheet can maintain a predetermined shape after coating by a die-coating printing method or the like. Further, by setting the viscosity to 100pa·s or less, defects such as the coating mark of the mold not disappearing can be prevented, and the printability can be improved.

The method for producing the inorganic fine particle-dispersed slurry composition of the present invention is not particularly limited, and conventionally known stirring methods are exemplified, and specifically, examples thereof include: and a method in which the (meth) acrylic resin composition, the inorganic fine particles, the organic solvent, and other components such as a plasticizer, if necessary, are stirred by a three-roll machine or the like. The order of addition of the constituent components of the inorganic fine particle-dispersed slurry composition can be appropriately set.

The inorganic fine particle dispersion slurry composition of the present invention can be applied to a support film subjected to a single-sided release treatment, and an organic solvent is dried and molded, thereby producing an inorganic fine particle dispersion molded article. Such an inorganic fine particle dispersion molded article is also one of the present invention.

The shape of the inorganic fine particle-dispersed molded article of the present invention is not particularly limited, and for example, it may be formed into a sheet or the like.

Examples of the method for producing the inorganic fine particle-dispersed molded article of the present invention include: a method of uniformly forming a coating film on a support film by using a coating system such as a roll coater, a die coater, a squeeze coater, or a curtain coater.

In the case of producing an inorganic fine particle-dispersed molded article, it is preferable that the polymer liquid is directly used as the inorganic fine particle-dispersed slurry composition, and the inorganic fine particle-dispersed molded article is produced without drying the high molecular weight (meth) acrylic resin.

This is because, when the high molecular weight (meth) acrylic resin is dried, undried particles called particles are generated during the re-dissolution, and such particles are difficult to remove even by filtration using a filter element filter or the like, and adversely affect the strength of the inorganic fine particle-dispersed molded product.

For example, when the inorganic fine particle-dispersed molded article of the present invention is in the form of a sheet, the support film used in producing the inorganic fine particle-dispersed molded article of the present invention is preferably a resin film having heat resistance and solvent resistance and flexibility. By imparting flexibility to the support film, the inorganic fine particle dispersion slurry composition can be applied to the surface of the support film by a roll coater, a blade coater, or the like, and the resulting inorganic fine particle dispersion sheet can be stored and supplied in a state of being wound into a roll.

Examples of the resin for forming the support film include: fluorine-containing resins such as polyethylene terephthalate, polyester, polyethylene, polypropylene, polystyrene, polyimide, polyvinyl alcohol, polyvinyl chloride, polyvinyl fluoride, nylon, cellulose, and the like.

The thickness of the support film is preferably 20 to 100. Mu.m, for example.

In addition, the release treatment is preferably performed on the surface of the support film, whereby the support film can be easily peeled off in the transfer step.

The inorganic fine particle-dispersed slurry composition of the present invention can be applied and dried to produce an inorganic fine particle-dispersed molded article.

The inorganic fine particle dispersion slurry composition and the inorganic fine particle dispersion molded product of the present invention can be used for dielectric green sheets and electrode pastes to produce laminated ceramic capacitors. Further, the use of the inorganic fine particle-dispersed slurry composition and the inorganic fine particle-dispersed molded article of the present invention can produce a magnetic material.

As a method for manufacturing the above-described laminated ceramic capacitor, there is mentioned: the method for producing a dielectric sheet comprises a step of producing a dielectric sheet by printing a conductive paste on the inorganic fine particle dispersion molded product of the present invention and drying the conductive paste, and a step of laminating the dielectric sheets.

The conductive paste contains a conductive powder.

The material of the conductive powder is not particularly limited as long as it is a material having conductivity, and examples thereof include: nickel, palladium, platinum, gold, silver, copper, molybdenum, tin, alloys thereof, and the like. These conductive powders may be used alone or in combination of 2 or more.

The method of printing the conductive paste is not particularly limited, and examples thereof include: screen printing, die printing, offset printing, gravure printing, inkjet printing, and the like.

In the method for manufacturing a laminated ceramic capacitor, the dielectric sheets on which the conductive paste is printed are laminated to obtain the laminated ceramic capacitor.

Effects of the invention

According to the present invention, there can be provided a (meth) acrylic resin composition having excellent decomposability at low temperature and capable of improving dispersibility of inorganic fine particles and an aggregation-inhibiting effect. Further, an inorganic fine particle dispersion slurry composition and an inorganic fine particle dispersion molded article using the (meth) acrylic resin composition can be provided.

Detailed Description

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Production examples 1 to 28, production of high molecular weight (meth) acrylic resin

A 2L separable flask equipped with a stirrer, a cooler, a thermometer, a hot water bath, and a nitrogen gas inlet was prepared, and 100 parts by weight of the total monomers were charged into the 2L separable flask so as to be blended as shown in table 1. Further, 50 parts by weight of butyl acetate as an organic solvent was mixed to obtain a monomer mixture.

The following monomers were used as the monomers.

MMA: methyl methacrylate

EMA: methacrylic acid ethyl ester

nBMA: n-butyl methacrylate

iBMA: isobutyl methacrylate

2EHMA: 2-ethylhexyl methacrylate

HEMA: methacrylic acid 2-hydroxy ethyl ester

HPMA: 2-hydroxy propyl methacrylate

HBMA: methacrylic acid 2-hydroxybutyl ester

After the dissolved oxygen was removed by bubbling the obtained monomer mixture for 20 minutes with nitrogen, the inside of the separable flask system was replaced with nitrogen, and the temperature was raised to boiling in a hot water bath while stirring. The polymerization initiator and the chain transfer agent were added in such amounts as shown in table 1.

After 7 hours from the start of the polymerization, the mixture was cooled to room temperature, and the polymerization was terminated. Then, the resulting resin solution was dried in an oven at 130 ℃ to remove the organic solvent. Thus, a high molecular weight (meth) acrylic resin was obtained.

The following substances were used as the polymerization initiator and the chain transfer agent.

< polymerization initiator >)

Tert-butyl peroxypivalate

< chain transfer agent >)

CT-1: 3-mercapto-1, 2-propanediol

CT-2: 3-mercapto-1-propanol

CT-3: 3-mercapto-2-butanol

CT-4: 8-mercapto-1-octanol

CT-5: mercaptosuccinic acid

TABLE 1

Production examples 29 to 62, production of Low molecular weight (meth) acrylic resin and other (meth) acrylic resins

A2L separable flask equipped with a stirrer, a cooler, a thermometer, a hot water bath, and a nitrogen gas inlet was prepared. Into a 2L separable flask, 100 parts by weight of the total monomers were charged so as to be blended as shown in Table 2. 50 parts by weight of butyl acetate as an organic solvent was further mixed to obtain a monomer mixture.

The same monomers as those described in production examples 1 to 28 were used as the monomers.

After the dissolved oxygen was removed by bubbling the obtained monomer mixture for 20 minutes with nitrogen, the inside of the separable flask system was replaced with nitrogen, and the temperature was raised to boiling in a hot water bath while stirring. The polymerization initiator and the chain transfer agent were added so as to be of the types and the amounts shown in Table 2.

After 7 hours from the start of the polymerization, the mixture was cooled to room temperature, and the polymerization was terminated. Then, the resulting resin solution was dried in an oven at 130 ℃ to remove the organic solvent. Thus, a low molecular weight (meth) acrylic resin was obtained.

The polymerization initiator and the chain transfer agent were the same as those described in production examples 1 to 28.

TABLE 2

/>

Examples 1 to 29 and comparative examples 1 to 8

(1) Preparation of resin composition

The organic solvents were mixed so as to be blended as shown in table 4, to obtain a mixed solvent. The (meth) acrylic resin and the mixed solvent were mixed so as to be blended as shown in table 3, to obtain a (meth) acrylic resin composition.

The following organic solvents were used as the organic solvents.

Toluene (toluene)

Acetic acid ethyl ester

Methyl ethyl ketone

Ethanol

Isopropyl alcohol

2-butyl-2-ethyl-1, 3-propanediol (BEPG)

Neopentyl glycol (NPG)

TEXANOL

(2) Preparation of inorganic microparticle-dispersed slurry composition

To the obtained (meth) acrylic resin composition, ceramic powder and plasticizer were added so as to be blended in table 3, and the mixture was kneaded by a high-speed mixer to prepare an inorganic fine particle-dispersed slurry composition.

Copper powder (manufactured by rattan metal Co., ltd., average particle diameter of 0.1 μm) and glass frit (manufactured by AGC Co., average particle diameter of 0.8 μm) were used as ceramic powder, and di (butoxyethyl) adipate was used as a plasticizer.

< evaluation >

The high molecular weight (meth) acrylic resin, the low molecular weight (meth) acrylic resin, and the inorganic fine particle dispersion slurry composition obtained in examples and comparative examples were evaluated as follows. The results are shown in tables 1 to 3.

(1) Weight average molecular weight determination

The weight average molecular weight (Mw) in terms of polystyrene was measured by gel permeation chromatography using LF-804 (manufactured by SHOKO Co.) as a column for the obtained high molecular weight (meth) acrylic resin and low molecular weight (meth) acrylic resin.

(2) Calculation of the weight concentration of OH groups

The weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin, the weight concentration of OH groups contained in the low molecular weight (meth) acrylic resin, and the weight concentration of OH groups contained in the organic solvent were calculated by the following methods.

Weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin: [ weight of OH groups contained in the whole monomer/(weight of the whole monomer+weight of the polymerization initiator) ]. Times.100

Weight concentration of OH groups contained in the low molecular weight (meth) acrylic resin: [ (weight of OH groups contained in the whole monomer+weight of OH groups contained in the chain transfer agent)/(weight of the whole monomer+weight of the chain transfer agent+weight of the polymerization initiator) ]. Times.100

Weight concentration of OH groups contained in the organic solvent: (weight of OH groups contained in the organic solvent/weight of the organic solvent) ×100

(3) Calculation of the weight concentration of S atoms

The weight concentration of S atoms contained in the (meth) acrylic resin was calculated by the following method.

When the (meth) acrylic resin composition contains a plurality of types of (meth) acrylic resins, the weight concentration of the S atom is calculated based on the weight concentration of the S atom contained in each (meth) acrylic resin and the blending ratio of each (meth) acrylic resin.

(4) Determination of solubility in ethanol

The amount of the high molecular weight (meth) acrylic resin added to the ethanol was determined as the solubility in ethanol, the amount being required to produce a precipitate, by dissolving the obtained high molecular weight (meth) acrylic resin in a small amount per 100 parts by weight of ethanol at 25 ℃.

(5) Low temperature decomposability (TGDTA characteristics)

The obtained inorganic fine particle dispersion slurry composition was filled in a platinum pan of TG-DTA, and the temperature was raised from 30 ℃ at 5 ℃/min, and the solvent was evaporated to thermally decompose the resin and plasticizer. Then, the measured weight showed 52.1 wt% (90 wt% end of degreasing) of time.

(6) Filterability

An injector of 2ml to 2.5ml of the obtained inorganic fine particle-dispersed slurry composition was attached to the tip of the injector, and an injection needle of 0.81mm in outside diameter, 0.51mm in inside diameter and 38mm in length was attached to the tip of the injector, and the time until the slurry composition was completely discharged from the tip of the injection needle when a force of 5kgf was applied was measured.

When the time required for the slurry composition to be discharged from the entire tip of the injection needle is short, it is considered that the filterability is excellent, and when the filterability is excellent, it is considered that the aggregation inhibition effect of the inorganic fine particles is high.

(7) Surface roughness

Printing of the inorganic fine particle dispersion paste composition was performed using a screen printer, a screen plate, and a printing glass substrate at a temperature of 23 ℃ and a humidity of 50%, and solvent drying was performed in a blast oven at a temperature of 100 ℃ for 30 minutes. Using the obtained printed pattern, 10 parts were measured by a surface roughness meter (Surfcom, manufactured by tokyo precision company).

The following products were used as screen printers, screen plates, and printed glass substrates.

Screen printer (MT-320 TV, manufactured by Micro Tec company)

Screen printing plate (manufactured by Tokyo Process Service company, ST500, emulsion 2 μm 2012 pattern, screen frame 320 mm. Times.320 mm)

Printed glass substrate (sodium glass, 150 mm. Times.150 mm, thickness 1.5 mm)

If the surface roughness is small, it is considered that the dispersibility of the inorganic fine particles is excellent.

(8) Ethanol cleanability

To 10 parts by weight of the inorganic fine particle dispersion slurry composition, 100 parts by weight of ethanol was added, and ultrasonic waves were irradiated. The time until the resin was completely dissolved in ethanol was measured.

TABLE 3

TABLE 4

Industrial applicability

Claims

1. A (meth) acrylic resin composition comprising a (meth) acrylic resin and an organic solvent,

the (meth) acrylic resin composition satisfies any one of the following (1) to (3),

The concentration of OH groups contained in the organic solvent is 9.0 wt% or more and 28.0 wt% or less,

(1) The (meth) acrylic resin contains a high molecular weight (meth) acrylic resin A having a weight average molecular weight of 12 to 30 ten thousand,

the weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin A is 0.4 wt% or more and 2.0 wt% or less;

(2) The (meth) acrylic resin contains a high molecular weight (meth) acrylic resin B having a weight average molecular weight of more than 30 ten thousand and 50 ten thousand or less,

the weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin B is 1.3 wt% or more and 3.5 wt% or less;

(3) The (meth) acrylic resin contains a low molecular weight (meth) acrylic resin C having a weight average molecular weight of 0.5 to 10 ten thousand,

the concentration of OH groups contained in the low molecular weight (meth) acrylic resin C is 1.3 wt% or more and 3.5 wt% or less,

the weight concentration of S atoms contained in the (meth) acrylic resin is 250ppm to 20000 ppm.

2. The (meth) acrylic resin composition according to claim 1, which satisfies (1) and contains a low molecular weight (meth) acrylic resin having a weight average molecular weight of 0.5 to 10 tens of thousands, wherein the low molecular weight (meth) acrylic resin has an OH group concentration of 1.3 to 3.5 wt% relative to 100 parts by weight of the high molecular weight (meth) acrylic resin a, and the low molecular weight (meth) acrylic resin has a content of 0.1 to 10 parts by weight.

3. The (meth) acrylic resin composition according to claim 1, which satisfies (1) or (2), and the solubility of the high molecular weight (meth) acrylic resin a or the high molecular weight (meth) acrylic resin B in ethanol is 10 parts by weight or more per 100 parts by weight of ethanol.

4. The (meth) acrylic resin composition according to claim 1 or 3, which satisfies (1) or (2), and wherein the high molecular weight (meth) acrylic resin A or the high molecular weight (meth) acrylic resin B contains 79% by weight or more and 96% by weight or less of the structural unit represented by the following formula (a) and 3.1% by weight or more and 17% by weight or less of the structural unit represented by the following formula (B) relative to the total structural units,

in the formula (a), R ¹ Represents a carbon number of 1 to 8A linear or branched alkyl group of the formula (b), R ² Represents a linear or branched alkyl group having 2 to 4 carbon atoms, at least 1 of which is substituted with an OH group.

5. The (meth) acrylic resin composition according to claim 1, 3 or 4, which satisfies (1) or (2), and the ratio of the weight concentration of OH groups contained in the organic solvent to the weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin a or the high molecular weight (meth) acrylic resin B, that is, the weight concentration of OH groups contained in the organic solvent/the weight concentration of OH groups contained in the high molecular weight (meth) acrylic resin a or the high molecular weight (meth) acrylic resin B is 4.5 or more and 46.2 or less.

6. The (meth) acrylic resin composition according to claim 1, 3, 4 or 5, which satisfies (2), and the (meth) acrylic resin is composed of only the high molecular weight (meth) acrylic resin B,

7. An inorganic fine particle-dispersed slurry composition comprising the (meth) acrylic resin composition according to any one of claims 1 to 6, inorganic fine particles and a plasticizer.

8. An inorganic fine particle dispersion molded article obtained by using the inorganic fine particle dispersion slurry composition according to claim 7.