CN118139925A

CN118139925A - Polyvinyl acetal resin composition, inorganic fine particle dispersion slurry composition, and laminated ceramic capacitor

Info

Publication number: CN118139925A
Application number: CN202380014116.8A
Authority: CN
Inventors: 大东裕司; 中村和人; 水守玲; 奥野伸一
Original assignee: Sekisui Chemical Co Ltd
Current assignee: Sekisui Chemical Co Ltd
Priority date: 2022-03-29
Filing date: 2023-03-20
Publication date: 2024-06-04
Also published as: TW202402834A; WO2023189847A1

Abstract

Disclosed is a polyvinyl acetal resin composition which has particularly excellent thermal decomposition properties and can exhibit high solvent solubility. Further provided is an inorganic fine particle dispersion slurry composition and a laminated ceramic capacitor. The present invention relates to a polyvinyl acetal resin composition having a water content of 5.0 wt% or less, which contains a polyvinyl acetal resin and a compound a containing carbon atoms, hydrogen atoms and oxygen atoms, wherein the ratio of the number of oxygen atoms to the total number of atoms (number of oxygen atoms/total number of atoms) is 0.18 or more.

Description

Polyvinyl acetal resin composition, inorganic fine particle dispersion slurry composition, and laminated ceramic capacitor

Technical Field

The present invention relates to a polyvinyl acetal resin composition, an inorganic fine particle dispersion slurry composition, and a laminated ceramic capacitor.

Background

In recent years, miniaturization and lamination of electronic components mounted on various electronic devices have been advanced, and laminated electronic components such as multilayer circuit boards, laminated coils, and laminated ceramic capacitors have been widely used.

Among them, a laminated ceramic capacitor is generally manufactured through the following steps.

First, a binder resin such as a polyvinyl butyral resin or a poly (meth) acrylate resin is dissolved in an organic solvent, a plasticizer, a dispersant, or the like is added to the obtained solution, and then ceramic raw material powder is added, and the mixture is uniformly mixed by a mixing device such as a bead mill or a ball mill, and a ceramic slurry composition having a certain viscosity is obtained after deaeration. The slurry composition is cast onto a surface of a support such as a polyethylene terephthalate film or an SUS plate subjected to a mold release treatment using a doctor blade, a reverse roll coater, or the like, and the volatile components such as a solvent are distilled off by heating the support, and then peeled off from the support to obtain a ceramic green sheet.

Next, a conductive paste to be an internal electrode was applied to the obtained ceramic green sheet by screen printing, and the thus obtained sheets were alternately stacked in a plurality of sheets and subjected to thermocompression bonding to produce a laminate. Then, a process of removing the binder resin component and the like contained in the laminate by thermal decomposition, so-called degreasing, is performed, and the external electrode is sintered at the end face of the obtained ceramic sintered body to obtain the laminated ceramic capacitor.

For example, patent document 1 describes, as a polyvinyl acetal resin suitable as a ceramic binder: a polyvinyl acetal resin having a predetermined polymerization degree, a content of vinyl ester units, and an acetalization degree, and a molar ratio of a portion acetalized with acetaldehyde to a portion acetalized with butyraldehyde within a predetermined range.

Patent document 2 describes that: a polyvinyl acetal resin having a specific structural unit and having a predetermined polymerization degree, a content of vinyl ester units, and an acetalization degree.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2011-236304

Patent document 2: international publication No. 2012/023617

Disclosure of Invention

Problems to be solved by the invention

However, when a polyvinyl acetal resin is used as the binder resin, the sheet strength is high, but the thermal decomposition property is poor, so that there is a problem that a part of the binder is not decomposed and burned off and remains as residual carbide in the sintered body.

The purpose of the present invention is to provide a polyvinyl acetal resin composition which has particularly excellent thermal decomposition properties and can exhibit high solvent solubility. Further, it is an object to provide an inorganic fine particle dispersion slurry composition and a laminated ceramic capacitor.

Means for solving the problems

The present disclosure (1) relates to a polyvinyl acetal resin composition having a water content of 5.0 wt% or less, the polyvinyl acetal resin composition comprising a polyvinyl acetal resin and a compound a, the compound a containing a carbon atom, a hydrogen atom and an oxygen atom, and a ratio of the number of oxygen atoms to the total number of atoms (number of oxygen atoms/total number of atoms) being 0.18 or more.

The present disclosure (2) relates to the polyvinyl acetal resin composition of the present disclosure (1), wherein the polyvinyl acetal resin composition contains 2.8 parts by weight or more and 20 parts by weight or less of the compound a relative to 100 parts by weight of the polyvinyl acetal resin.

The present disclosure (3) relates to the polyvinyl acetal resin composition of the present disclosure (1) or (2), wherein, when the solubility parameter value of the polyvinyl acetal resin calculated by the Fedors method is S1 and the solubility parameter of the compound a is S2, the absolute value of the difference between S1 and S2 is 9.0 (cal/cm ³)^0.5 or less).

The present disclosure (4) relates to the polyvinyl acetal resin composition of any combination of any of the (1) to (3) of the present disclosure, wherein the molecular weight of the compound a is 90 or more and 450 or less.

The present disclosure (5) relates to a polyvinyl acetal resin composition of any combination of any of the present disclosure (1) to (4), wherein the compound a is at least 1 selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2),

[ Chemical formula 1]

R¹-R²-R³ (1)

R⁴-R⁵-R⁶ (2)

In the formula (1), R ¹ and R ³ represent a carboxyl group or a salt thereof, and R ² represents a single bond, a 2-valent group containing a carbon atom, a hydrogen atom or an oxygen atom, which is optionally substituted with a hydroxyl group and a carboxyl group or a salt thereof.

In the formula (2), R ⁴ and R ⁶ each independently represent a hydrogen atom, a hydroxyl group, an acetyl group, or an acetoxy group, and R ⁵ represents a 2-valent group containing a carbon atom, a hydrogen atom, and an oxygen atom, which is optionally substituted with a hydroxyl group, an acetyl group, an acetoxy group, a carboxyl group, or a salt thereof.

The present disclosure (6) relates to the polyvinyl acetal resin composition of the present disclosure (5), wherein in the formula (1), R ² is a single bond, a linear alkylene group having 1 to 6 carbon atoms and having at least 1 of a hydroxyl group, a carboxyl group, or a salt thereof, or a branched alkylene group having 3 to 6 carbon atoms and having at least 1 of a hydroxyl group, a carboxyl group, or a salt thereof.

The present disclosure (7) relates to the polyvinyl acetal resin composition of the present disclosure (5) or (6), wherein in the formula (2), R ⁵ is a linear alkylene group having 1 to 6 carbon atoms, having at least 1 of a hydroxyl group, an acetyl group, an acetoxy group, a carboxyl group or a salt thereof, a branched alkylene group having 3 to 6 carbon atoms, having at least 1 of a hydroxyl group, an acetyl group, an acetoxy group, a carboxyl group or a salt thereof, or a glycerin unit having a repetition number of 2 to 11.

The present disclosure (8) relates to the polyvinyl acetal resin composition of any combination of any of the present disclosure (5) to (7), wherein the compound represented by formula (1) is at least 1 compound selected from tartaric acid, malic acid, citric acid, and salts thereof.

The present disclosure (9) relates to the polyvinyl acetal resin composition of any combination of any of the present disclosure (5) to (8), wherein the compound represented by formula (2) is at least 1 compound selected from pentaerythritol and pentaerythritol tetraacetate.

The present disclosure (10) relates to a polyvinyl acetal resin composition of any combination of any of the present disclosure (1) to (9), wherein a Y value represented by the following formula is 6.3×10 ^-9 or more and 45.0×10× 10 ^-9 or less,

Y＝((W_A÷M_A×O_R)÷(100-W_W))÷(M_PVB÷M_A)÷S^0.4

W _A: content of Compound A relative to 100 parts by weight of the polyvinyl acetal resin

M _A: molecular weight of Compound A

O _R: the ratio of the number of oxygen atoms to the total number of atoms (number of oxygen atoms/total number of atoms) in Compound A

W _W: water content of polyvinyl acetal resin composition

M _PVB: weight average molecular weight of polyvinyl acetal resin

S: the value of the solubility parameter of the polyvinyl acetal resin calculated by the Fedors method is S1, and the absolute value of the difference between S1 and S2 when the solubility parameter of the compound a is S2.

The present disclosure (11) relates to an inorganic fine particle dispersion slurry composition containing the polyvinyl acetal resin composition according to any one of (1) to (10) of the present disclosure, an organic solvent, and inorganic fine particles.

The present disclosure (12) relates to an inorganic fine particle dispersion slurry composition of the present disclosure (11), which further contains a plasticizer.

The present disclosure (13) relates to the inorganic fine particle-dispersed slurry composition of the present disclosure (11) or (12), wherein the inorganic fine particles are barium titanate powder or nickel powder.

The present disclosure (14) relates to a laminated ceramic capacitor having a dielectric layer or an electrode layer formed using the inorganic fine particle dispersion slurry composition according to any one of the present disclosure (11) to (13).

The present invention will be described in detail below.

As a result of intensive studies, the present inventors have found that by adding a compound a having a specific structure to a polyvinyl acetal resin and preparing a resin composition having a water content of 5wt% or less, the thermal decomposition properties of the polyvinyl acetal resin can be improved, and further the solvent solubility can be improved, and completed the present invention.

The polyvinyl acetal resin composition contains a polyvinyl acetal resin.

The polyvinyl acetal resin generally includes a structural unit having a hydroxyl group represented by the following formula (a-1), a structural unit having an acetyl group represented by the following formula (a-2), and a structural unit having an acetal group represented by the following formula (a-3).

[ Chemical formula 2]

In the above formula (a-3), R ^1a represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

Examples of the alkyl group having 1 to 20 carbon atoms include: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, and the like. Among them, methyl, ethyl and propyl are preferable.

The content of the structural unit having a hydroxyl group represented by the formula (a-1) (hereinafter referred to as "hydroxyl group amount") in the polyvinyl acetal resin is preferably 18 mol% or more, more preferably 20 mol% or more, and still more preferably 22 mol% or more, from the viewpoint of improving the toughness of the resin. Further, from the viewpoint of further improving the solvent solubility, it is preferably 50 mol% or less, more preferably 39 mol% or less, and still more preferably 38 mol% or less. The hydroxyl group amount is preferably 18 to 50 mol%, more preferably 20 to 39 mol%, and still more preferably 22 to 38 mol%.

The hydroxyl group amount can be measured by NMR, for example.

The content of the structural unit having an acetyl group represented by the formula (a-2) (hereinafter referred to as "acetyl group amount") in the polyvinyl acetal resin is preferably 0.5 mol% or more, more preferably 0.6 mol% or more, and even more preferably 1 mol% or more, from the viewpoint of suppressing an increase in viscosity. In view of not excessively improving the flexibility of the polyvinyl acetal resin and improving the handling property, the content is preferably 20 mol% or less, more preferably 16 mol% or less, and still more preferably 14 mol% or less. The amount of the acetyl group is preferably 0.5 to 20 mol%, more preferably 0.6 to 16 mol%, and still more preferably 1 to 14 mol%.

The acetyl group amount can be measured by NMR, for example.

The content of the structural unit having an acetal group represented by the formula (a-3) (hereinafter referred to as "acetal group amount") in the polyvinyl acetal resin is preferably 45 mol% or more, more preferably 47 mol% or more, and still more preferably 49 mol% or more, from the viewpoint of further improving the solubility in a solvent. In order to improve the toughness of the resin, the resin is preferably 80 mol% or less, more preferably 78 mol% or less, and still more preferably 76 mol% or less.

The amount of the acetal group is preferably 45 to 80 mol%, more preferably 47 to 78 mol%, and still more preferably 49 to 76 mol%.

The amount of the acetal group can be measured by NMR, for example.

In the method for calculating the amount of acetal groups, since the acetal groups of the polyvinyl acetal resin are obtained by acetalizing 2 hydroxyl groups of polyvinyl alcohol, a method of counting the number of structural units having an acetal group by converting the structural units having an acetal group into 2 structural units having a hydroxyl group may be employed.

The polyvinyl acetal resin may have other structural units in addition to the structural units of the formulae (a-1), (a-2), and (a-3). Examples of the other structural unit include a structural unit having a functional group such as a carboxyl group, a sulfonic acid group, an oxyalkylene group, an amide group, and an ethylene unit.

Examples of the structural unit having a carboxyl group include a structural unit represented by the following formula (b-1), a structural unit represented by the following formula (b-2), and a structural unit represented by the following formula (b-3).

[ Chemical formula 3]

In the above formula (b-1), R ^1b and R ^2b each independently represent an alkylene group having 0 to 10 carbon atoms, and X ^1b and X ^2b each independently represent a hydrogen atom, a metal atom or a methyl group.

In the above formula (b-1), the lower limit of the number of carbon atoms of the alkylene group represented by R ^1b and R ^b2 is preferably 0, the upper limit is preferably 5, the lower limit is more preferably 1, and the upper limit is more preferably 3. The number of carbon atoms of the alkylene group is more preferably 0 to 5, still more preferably 1 to 3.

R ^1b and R ^2b may be the same or different, and are preferably different. In addition, at least one of them is preferably a single bond.

Examples of the alkylene group having 0 to 10 carbon atoms include: straight-chain alkylene such as single bond, methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, octamethylene, decamethylene, branched alkylene such as methylethylene, 1-methylpentylene, 1, 4-dimethylbutylene, and cyclic alkylene such as cyclopropylene, cyclobutylene, and cyclohexylene. Among them, the linear alkylene group such as a single bond, a methylene group, an ethylene group, an n-propylene group, or an n-butylene group is preferable, and a single bond, a methylene group, or an ethylene group is more preferable.

In the above (b-1), when at least one of X ^1b and X ^2b is a metal atom, examples of the metal atom include: sodium atom, lithium atom, potassium atom, and the like. Among them, sodium atom is preferable.

The structural unit represented by the above formula (b-1) is preferably derived from an α -dicarboxylic monomer. Examples of the α -dicarboxylic monomer include: dicarboxylic acids having radically polymerizable unsaturated double bonds such as methylene malonic acid, itaconic acid, 2-methyleneglutaric acid, 2-methyleneadipic acid, and 2-methylenesebacic acid, metal salts thereof, and methyl esters thereof. Among them, itaconic acid, a metal salt thereof or a methyl ester thereof is preferably used.

In the present specification, an α -dicarboxylic monomer means a monomer having 2 carboxyl groups at the α -position carbon.

In the above formula (b-2), R ^3b、R^4b and R ^5b each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R ^6b represents an alkylene group having 0 to 10 carbon atoms, and X ^3b represents a hydrogen atom, a metal atom or a methyl group.

In the above formula (b-2), the lower limit of the number of carbon atoms of the alkyl group represented by R ^3b、R^4b and R ^5b is preferably 1, the upper limit is preferably 5, and the upper limit is more preferably 3. The number of carbon atoms of the alkyl group is more preferably 1 to 5, and still more preferably 1 to 3.

R ^3b、R^4b、R^5b may be the same or different, and more preferably the same. R ^3b、R^4b and R ^5b are preferably hydrogen atoms.

Examples of the alkyl group having 1 to 10 carbon atoms include: straight-chain alkyl groups such as methyl, ethyl, propyl, n-butyl, n-pentyl, n-heptyl, n-octyl, n-nonyl, and n-decyl, branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-dimethylpropyl, 1, 3-tetramethylbutyl, and 2-ethylhexyl, and cycloalkyl groups such as cyclopropyl, cyclopropylmethyl, cyclobutyl, cyclopentyl, and cyclohexyl. Among them, a linear alkyl group such as methyl, ethyl, propyl, or n-butyl is preferable, and methyl and ethyl are more preferable.

R ^6b in the above formula (b-2) is the same as those exemplified for R ^1b and R ^2b in the above formula (b-1), and among them, a linear alkylene group such as a single bond, methylene, ethylene, trimethylene or tetramethylene group is preferable, a single bond, methylene or ethylene is more preferable, and a single bond is still more preferable.

In the above formula (b-2), when X ^3b is a metal atom, examples of the metal atom include: sodium atom, lithium atom, potassium atom, and the like. Among them, sodium atom is preferable.

The structural unit represented by the above formula (b-2) is preferably derived from a monocarboxylic acid monomer. Examples of the monocarboxylic acid monomer include: monocarboxylic acids having radically polymerizable unsaturated double bonds such as acrylic acid, crotonic acid, methacrylic acid and oleic acid, metal salts thereof and methyl esters thereof. Among them, crotonic acid, a metal salt thereof or a methyl ester thereof is preferably used.

In the above formula (b-3), R ^7b and R ^9b each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R ^8b and R ^10b each represent an alkylene group having 0 to 10 carbon atoms, and X ^4b and X ^5b each represent a hydrogen atom, a metal atom or a methyl group.

In the above formula (b-3), the lower limit of the number of carbon atoms of the alkyl group represented by R ^7b and R ^9b is preferably 1, the upper limit is preferably 5, and the upper limit is more preferably 3.

R ^7b and R ^9b may be the same or different, and are more preferably the same.

R ^7b and R ^9b in the above formula (b-3) are the same groups as those exemplified for R ^3b、R^4b and R ^5b in the above formula (b-2), and among them, a hydrogen atom is preferable.

R ^8b and R ^10b in the above formula (b-3) are the same groups as those exemplified for R ^1b and R ^2b in the above formula (b-1), and among them, linear alkylene groups such as a single bond, methylene, ethylene, trimethylene and tetramethylene are preferable, single bond, methylene and ethylene are more preferable, and single bond is still more preferable.

In the above formula (b-3), when X ^4b and X ^5b are metal atoms, examples of the metal atoms include: sodium atom, lithium atom, potassium atom, and the like. Among them, sodium atom is preferable.

The structural unit having a sulfonic acid group includes a structural unit represented by the following formula (c).

[ Chemical formula 4]

In the formula (c), R ^1c represents an alkylene group having 0 to 10 carbon atoms, and X ^1c represents a hydrogen atom, a metal atom or a methyl group.

R ^1c in the above formula (c) is the same as those exemplified for R ^1b and R ^2b in the above formula (b-1), and among them, a linear alkylene group such as a single bond, methylene, ethylene, trimethylene or tetramethylene group is preferable, a single bond, methylene or ethylene group is more preferable, and a single bond or methylene group is still more preferable.

In the above formula (c), when X ^1c is a metal atom, examples of the metal atom include: sodium atom, lithium atom, potassium atom, and the like. Among them, sodium atom is preferable.

The structural unit having an oxyalkylene group includes a structural unit represented by the following formula (d).

[ Chemical formula 5]

In the formula (d), R ^d1 represents a group having an oxyalkylene group having 2 to 6 carbon atoms.

Examples of the alkylene oxide group having 2 to 6 carbon atoms include an ethylene oxide group, a propylene oxide group, a butylene oxide group, a pentylene oxide group, and a hexylene oxide group.

Examples of the structural unit having an oxyalkylene group represented by the above formula (d) include: structural units having a plurality of oxyethylene groups such as polyethylene glycol, structural units having an oxyethylene group alone, structural units having different oxyalkylene groups, and the like.

The structural unit having an oxyalkylene group is preferably a structural unit having an oxyethylene group represented by the following formula (e-1) or a structural unit having an oxyethylene group and an oxypropylene group represented by the following formula (e-2). The oxyethylene group and oxypropylene group may be arranged in any of a block or random manner.

[ Chemical formula 6]

In the above formula (e-1), R ^e1 and R ^e2 are each a single bond or a linking group having at least 1 kind selected from C and O, and n ₁ is an integer.

R ^e1 is a linking group having at least 1 kind selected from C and O or a single bond. R ^e1 is preferably an alkylene group having 1 to 10 carbon atoms, a carbonyl group or an oxygen atom. Examples of the R ^e1 include: methylene, ethylene, carbonyl, ether, allyl ether, amide, and the like.

R ^e2 is a linking group having at least 1 kind selected from C and O or a single bond. R ^e2 is preferably an alkylene group having 1 to 10 carbon atoms, a carbonyl group or an oxygen atom. Examples of the R ^e2 include: methylene, ethylene, propylene, carbonyl, ether groups, and the like.

The integer n ₁ as the repeating number of the alkylene oxide is not particularly limited, but is preferably 2 to 70, more preferably 5 to 50.

In the above formula (e-2), R ^e3、R^e4 and R ^e5 are each a single bond or a linking group having at least 1 kind selected from C and O, and n ₂ and n ₃ are each an integer.

Examples of R ^e3、R^e4 and R ^e5 include the same groups as those exemplified as R ^e1 and R ^e2 in the formula (e-1).

The integer n ₂、n₃ as the repeating number of the alkylene oxide is not particularly limited, but n ₂ is preferably 1 to 40, more preferably 20 to 30. Further, n ₃ is preferably 1 to 40, more preferably 20 to 30.

The structural unit having an amide group includes a structural unit represented by the following formula (f).

[ Chemical formula 7]

In the above formula (f), R ^1f represents an alkyl group having 1 to 10 carbon atoms.

R ^1f in the above formula (f) is the same as those exemplified for R ^3b、R^4b and R ^5b in the above formula (b-2), and among them, a linear alkyl group such as a hydrogen atom, methyl group, ethyl group, propyl group, or n-butyl group is preferable, and a hydrogen atom, methyl group, or ethyl group is more preferable.

The content of the structural unit having the functional group in the polyvinyl acetal resin is preferably 0 mol% or more, more preferably 0.1 mol% or more, still more preferably 0.5 mol% or more, preferably 5 mol% or less, and still more preferably 3 mol% or less. The content of the structural unit having the functional group is preferably 0 to 5 mol%, more preferably 0.1 to 5 mol%, and still more preferably 0.5 to 3 mol%.

The content of the structural unit having the functional group can be determined by NMR, for example.

The ethylene unit may be a structural unit represented by the following formula (g).

[ Chemical formula 8]

In the polyvinyl acetal resin, the content of the ethylene unit (hereinafter, also referred to as "ethylene content") is preferably 1 mol% or more, more preferably 3 mol% or more, preferably 20 mol% or less, and more preferably 10 mol% or less. The ethylene content is preferably 1 to 20 mol%, more preferably 3 to 10 mol%.

The ethylene content can be measured by NMR, for example.

In the present specification, the ethylene content of the polyvinyl acetal resin means the apparent ethylene content of the entire polyvinyl acetal resin. That is, for example, in the case where the polyvinyl acetal resin contains a plurality of resins having different ethylene contents, the ethylene contents of the polyvinyl acetal resins are obtained by summing up values obtained by multiplying the ethylene contents of the respective resins by the content ratio of the resins.

In the polyvinyl acetal resin, the ratio of the ethylene content to the hydroxyl group amount (ethylene content/hydroxyl group amount) is preferably 0.01 or more, and preferably 1.0 or less. The ethylene content/hydroxyl group content is preferably 0.01 to 1.0.

The average polymerization degree of the polyvinyl acetal resin is preferably 300 or more, more preferably 600 or more, still more preferably 1000 or more, and particularly preferably 1300 or more, from the viewpoint of improving mechanical strength. From the viewpoints of solvent solubility and viscosity, it is preferably 10000 or less, more preferably 8000 or less, further preferably 3500 or less, and particularly preferably 3000 or less. The average polymerization degree is preferably 300 to 10000, more preferably 600 to 8000, still more preferably 1000 to 3500, particularly preferably 1300 to 3000.

The average polymerization degree is the same as that of the raw material polyvinyl alcohol resin. The average polymerization degree of the raw material polyvinyl alcohol resin can be measured in accordance with JIS K6726.

The weight average molecular weight (Mw) of the polyvinyl acetal resin is preferably 80000 or more, preferably 2500000 or less, more preferably 150000 or more, more preferably 2000000 or less, more preferably 250000 or more, more preferably 875000 or less, more preferably 300000 or more, more preferably 440000 or less. The weight average molecular weight (Mw) is preferably 80000 ～ 2500000, more preferably 150000 ～ 2000000, still more preferably 250000 ～ 875000, and still more preferably 300000 ～ 440000.

The mechanical strength can be improved by setting the weight average molecular weight (Mw) of the polyvinyl acetal resin to the above lower limit or more, and the solvent solubility can be improved by setting the weight average molecular weight (Mw) to the above upper limit or less.

The weight average molecular weight described above can be determined by Gel Permeation Chromatography (GPC) using appropriate standards (e.g., polystyrene standards).

Examples of the column used for measuring the Mw include: TSKgel SuperHZM-H (manufactured by Tosoh corporation), and the like.

The content of the polyvinyl acetal resin in the polyvinyl acetal resin composition is preferably 80.0 wt% or more, more preferably 85.0 wt% or more, further preferably 90.0 wt% or more, preferably 97.2 wt% or less, more preferably 97.0 wt% or less, further preferably 96.5 wt% or less. The content of the polyvinyl acetal resin is preferably 80.0 to 97.2% by weight, more preferably 85.0 to 97.0% by weight, and still more preferably 90.0 to 96.5% by weight.

The polyvinyl acetal resin can be generally produced by acetalizing a polyvinyl alcohol resin.

As the polyvinyl alcohol resin, for example, it is possible to use: conventionally known polyvinyl alcohol resins such as resins produced by saponifying polyvinyl acetate resins with alkali, acid, ammonia water or the like.

The polyvinyl alcohol resin may be completely saponified, but it is not necessarily completely saponified, and may be partially saponified, as long as it has at least 1 unit in at least one position of the main chain, and has a unit having a 2-hydroxy group (a 2-hydroxy group in Japanese: a 2-hydroxy group) in the racemic (Japanese: a 2-o-group) position. Further, as the polyvinyl alcohol resin, a copolymer of a monomer copolymerizable with vinyl alcohol and vinyl alcohol, such as an ethylene-vinyl alcohol copolymer resin and a partially saponified ethylene-vinyl alcohol copolymer resin, may be used.

Examples of the polyvinyl acetate resin include ethylene-vinyl acetate copolymers.

The saponification degree of the polyvinyl alcohol resin is preferably 80 mol% or more, more preferably 84 mol% or more, further preferably 88 mol% or more, preferably 99.5 mol% or less, more preferably 99.4 mol% or less, further preferably 99 mol% or less. The saponification degree is preferably 80 to 99.5 mol%, more preferably 84 to 99.4 mol%, and still more preferably 88 to 99 mol%.

The acetalization may be carried out by a known method, preferably in an aqueous solvent, a mixed solvent of water and an organic solvent compatible with water, or an organic solvent.

As the organic solvent having compatibility with water, for example, an alcohol-based organic solvent can be used.

Examples of the organic solvent include: alcohol-based organic solvents, aromatic organic solvents, aliphatic ester-based solvents, ketone-based solvents, lower alkane-based solvents, ether-based solvents, amide-based solvents, amine-based solvents, and the like.

Examples of the alcohol-based organic solvent include: methanol, ethanol, n-propanol, isopropanol, n-butanol, t-butanol, etc.

Examples of the aromatic organic solvent include: xylene, toluene, ethylbenzene, methyl benzoate, and the like.

Examples of the aliphatic ester solvent include: methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, methyl acetoacetate, ethyl acetoacetate, and the like.

Examples of the ketone solvent include: acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, benzophenone, acetophenone, and the like.

Examples of the lower alkane solvent include: hexane, pentane, octane, cyclohexane, decane, and the like.

Examples of the ether solvent include: diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol diethyl ether, and the like.

Examples of the amide-based solvent include: n, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, acetanilide and the like.

Examples of the amine solvent include: ammonia, trimethylamine, triethylamine, N-butylamine, di-N-butylamine, tri-N-butylamine, aniline, N-methylaniline, N-dimethylaniline, pyridine and the like.

These solvents may be used alone or in combination of 2 or more solvents. Among these, ethanol, n-propanol, isopropanol, and tetrahydrofuran are particularly preferable from the viewpoints of solubility in the resin and easiness in purification.

The acetalization is preferably carried out in the presence of an acid catalyst.

The acid catalyst is not particularly limited, and examples thereof include: inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, carboxylic acids such as formic acid, acetic acid, and propionic acid, and sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. These acid catalysts may be used alone or in combination of 2 or more kinds. Among them, hydrochloric acid, nitric acid, and sulfuric acid are preferable, and nitric acid is particularly preferable.

The aldehyde used for acetalization includes an aldehyde having a chain aliphatic group having 1 to 10 carbon atoms, a cyclic aliphatic group, or an aromatic group. As these aldehydes, conventionally known aldehydes can be used. The aldehyde used in the acetalization reaction is not particularly limited, and examples thereof include aliphatic aldehydes and aromatic aldehydes.

Examples of the aliphatic aldehyde include: formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, n-caproaldehyde, 2-ethylbutyraldehyde, 2-ethylhexanal, n-heptanal, n-octanal, n-nonanal, n-decanal, valeraldehyde, and the like.

Examples of the aromatic aldehyde include: benzaldehyde, cinnamaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, beta-phenylpropionaldehyde, etc.

These aldehydes may be used alone or in combination of 1 or more than 2. Among them, formaldehyde, acetaldehyde, butyraldehyde, 2-ethylhexylaldehyde and n-nonanal are preferable, which have excellent acetalization reactivity, can impart a sufficient internal plasticizing effect to the produced resin, and can impart good flexibility as a result. Further, formaldehyde, acetaldehyde, and butyraldehyde are more preferable from the viewpoint of obtaining an adhesive composition particularly excellent in impact resistance and adhesion to metals.

The amount of the aldehyde to be added may be appropriately set in accordance with the amount of the acetal group of the target polyvinyl acetal resin.

The polyvinyl acetal resin composition contains a compound a.

The compound a contains a carbon atom, a hydrogen atom and an oxygen atom, and the ratio of the number of oxygen atoms to the total number of atoms (number of oxygen atoms/total number of atoms) is 0.18 or more.

The number of oxygen atoms/total number of atoms is preferably 0.19 or more, more preferably 0.30 or more, further preferably 0.35 or more, preferably 0.90 or less, more preferably 0.70 or less, further preferably 0.60 or less. The number of oxygen atoms per total number of atoms is preferably 0.18 to 0.90, more preferably 0.19 to 0.70, still more preferably 0.30 to 0.70, still more preferably 0.35 to 0.60.

By containing the compound a, the thermal decomposability of the polyvinyl acetal resin can be improved.

The molecular weight of the compound a is preferably 90 or more, more preferably 130 or more, further preferably 150 or more, preferably 10000 or less, more preferably 450 or less, further preferably 400 or less, from the viewpoint of improving the compatibility with the polyvinyl acetal resin and having the advantage of improving the thermal decomposition property. The molecular weight is preferably 90 to 10000, more preferably 130 to 450, and even more preferably 150 to 400.

The molecular weight is a calculated molecular weight.

The solubility parameter S1 of the polyvinyl acetal resin and the solubility parameter S2 of the compound a calculated by the Fedors method may be appropriately adjusted according to the application. The absolute value of the difference between S1 and S2 is preferably 9.0 (cal/cm ³)^0.5 or less, more preferably 8.5 (cal/cm ³)^0.5 or less, still more preferably 5.5 (cal/cm ³)^0.5 or less) from the viewpoint of improving the thermal decomposition property.

From the viewpoint of improving the compatibility with the polyvinyl acetal resin, the compound a is preferably at least 1 selected from the group consisting of the compounds represented by the following formula (1) and the compounds represented by the following formula (2).

[ Chemical formula 9]

R¹-R²-R³ (1)

R⁴-R⁵-R⁶ (2)

In the formula (1), R ¹ and R ³ represent a carboxyl group or a salt thereof, and R ² represents a single bond, a 2-valent group containing a carbon atom, a hydrogen atom and an oxygen atom, which is optionally substituted with a hydroxyl group and a carboxyl group or a salt thereof. Examples of the salts include lithium salts, sodium salts, and potassium salts.

In the formula (2), R ⁴ and R ⁶ each independently represent a hydrogen atom, a hydroxyl group, an acetyl group, or an acetoxy group, and R ⁵ represents a 2-valent group containing a carbon atom, a hydrogen atom, and an oxygen atom, which is optionally substituted with a hydroxyl group, an acetyl group, an acetoxy group, a carboxyl group, or a salt thereof. R ⁴ and R ⁶ may be the same or different, and are preferably the same.

R ² is preferably a single bond or a 2-valent hydrocarbon group optionally substituted with a hydroxyl group and a carboxyl group or a salt thereof.

Examples of the hydrocarbon group include: a linear alkylene group having 1 to 6 carbon atoms, a branched alkylene group having 3 to 6 carbon atoms, a linear alkenylene group having 2 to 6 carbon atoms, a branched alkenylene group having 3 to 6 carbon atoms, a cycloalkylene group having 3 to 6 carbon atoms, a cycloalkenylene group having 3 to 6 carbon atoms, an aromatic hydrocarbon group having 6 carbon atoms, and the like.

Among them, a linear alkylene group having 1 to 4 carbon atoms and a branched alkylene group having 3 to 4 carbon atoms are preferable, and a linear alkylene group having 1 to 3 carbon atoms is more preferable.

Examples of the linear alkylene group having 1 to 6 carbon atoms include: methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, and the like.

Examples of the branched alkylene group having 3 to 6 carbon atoms include: 1-methylethylene, 2-methyltrimethylene, 2-methyltetramethylene, 2-methylpentamethylene, and the like.

Examples of the linear alkenylene group having 2 to 6 carbon atoms include: ethenylene, propenylene, butenylene, hexenylene, and the like.

Examples of the branched alkenylene group having 3 to 6 carbon atoms include: isopropenylene, 1-ethylvinylidene, 2-methylpropylene, 2-dimethylbutylene, 3-methyl-2-butenylene, 3-ethyl-2-butenylene, and the like.

Examples of the cycloalkylene group having 3 to 6 carbon atoms include: cyclopentylene, cyclohexylene, and the like.

Examples of the cycloalkenyl group having 3 to 6 carbon atoms include: cyclopentylene, 2, 4-cyclopentadienyl, cyclohexenylene, and the like.

Examples of the aromatic hydrocarbon group having 6 carbon atoms include: 1, 2-phenylene, and the like.

R ² is preferably a single bond, a linear alkylene group having 1 to 6 carbon atoms and having at least 1 of a hydroxyl group, a carboxyl group or a salt thereof, or a branched alkylene group having 3 to 6 carbon atoms and having at least 1 of a hydroxyl group, a carboxyl group or a salt thereof, more specifically, a single bond, methylene, trimethylene, hydroxymethylene, hydroxyethylene, 1, 2-dihydroxyethylene, 2-hydroxy, 2-carboxytrimethylene, still more preferably hydroxyethylene, 1, 2-dihydroxyethylene, 2-hydroxy, 2-carboxytrimethylene.

Further, as the R ⁵, there may be mentioned: a 2-valent hydrocarbon group having at least 1 of a hydroxyl group, an acetyl group, an acetoxy group, a carboxyl group or a salt thereof, an acetyl group, a 2-valent group having a glycerin unit, and the like. The hydrocarbon group may be the same as the hydrocarbon group described as R ². Among them, a branched alkylene group having 3 to 5 carbon atoms and having at least 1 of a hydroxyl group, an acetyl group, an acetoxy group, a carboxyl group or a salt thereof, a 2-valent group having a glycerin unit are preferable, and a branched alkylene group having 3 to 5 carbon atoms and a glycerin unit having a repetition number of 2 to 11 are more preferable.

More specifically, R ⁵ is preferably a glycerol unit having 2, 2-dihydroxymethyltrimethylene, 2-diacetoxymethyltrimethylene or a repetition number of 2 to 11.

Specific examples of the compound represented by the above formula (1) include: aliphatic hydroxy acids such as citric acid, malic acid, tartaric acid, tartronic acid, isocitric acid, and mevalonic acid, and aliphatic dicarboxylic acids such as oxalic acid, malonic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, and suberic acid. Among them, citric acid, malic acid, and tartaric acid are preferable.

Specific examples of the compound represented by the above formula (2) include: pentaerythritol, pentaerythritol tetraacetate, glycerin, polyglycerin having 2 to 11 glycerin units, and the like. Among them, pentaerythritol and pentaerythritol tetraacetate are preferable.

The content of the compound a in the polyvinyl acetal resin composition is preferably 2.8 parts by weight or more, more preferably 3.0 parts by weight or more, and even more preferably 3.5 parts by weight or more, based on 100 parts by weight of the polyvinyl acetal resin, from the viewpoint of improving the thermal decomposition property. In view of improving the solvent solubility of the polyvinyl acetal resin composition, it is preferably 20.0 parts by weight or less, more preferably 15.0 parts by weight or less, and still more preferably 10.0 parts by weight or less. The content of the compound a is preferably 2.8 to 20.0 parts by weight, more preferably 3.0 to 15.0 parts by weight, and even more preferably 3.5 to 10.0 parts by weight, based on 100 parts by weight of the polyvinyl acetal resin.

The water content of the polyvinyl acetal resin composition is 5.0 wt% or less.

When the water content is 5.0% by weight or less, the handleability and solvent solubility of the polyvinyl acetal resin composition can be improved.

The water content is preferably 0.01wt% or more, more preferably 0.02 wt% or more, preferably 3.0 wt% or less, more preferably 2.0 wt% or less. The water content is preferably 0.01 to 5.0 wt%, more preferably 0.02 to 3.0 wt%, and even more preferably 0.02 to 2.0 wt%.

The water content refers to the water content in the polyvinyl acetal resin composition, and can be measured by infrared moisture meter and NMR.

The water content can be adjusted by the drying temperature and drying time after acetalization, and the drying temperature and drying time after mixing the polyvinyl acetal resin with the compound a.

The polyvinyl acetal resin composition preferably has a Y value represented by the following formula of 6.3×10 ^-9 or more and 45.0×10 ^-9 or less.

Y＝((W_A÷M_A×O_R)÷(100-W_W))÷(M_PVB÷M_A)÷S^0.4

M _A: molecular weight of Compound A

W _W: water content of polyvinyl acetal resin composition

M _PVB: weight average molecular weight of polyvinyl acetal resin

S: the absolute value of the difference between S1 and S2 when the solubility parameter of the polyvinyl acetal resin calculated by Fedors method is S1 and the solubility parameter of the compound A is S2

By satisfying the above conditions, the firing residue of the polyvinyl acetal resin composition can be reduced.

The Y value is more preferably 9.0×10 ^-9 or more, and still more preferably 15.0×10 ^-9 or less. The above Y value is preferably 6.3X10 ^-9～45.0×10^-9, more preferably 9.0X10 ^-9～15.0×10^-9.

The polyvinyl acetal resin composition may contain components such as a dispersant, an antioxidant, a plasticizer, and a surfactant, as long as the above effects are not impaired.

Examples of the method for producing the polyvinyl acetal resin composition include: the method of acetalizing polyvinyl alcohol with aldehyde, mixing the thus obtained polyvinyl acetal resin with the above compound a and other additives added as needed, and adjusting the water content by drying. Further, examples thereof include: a method of acetalizing polyvinyl alcohol with aldehyde in the presence of a compound A and drying the resultant product to adjust the water content.

Among them, a method of acetalizing polyvinyl alcohol with aldehyde, adding the above-mentioned compound a and other additives added as needed to the thus-obtained polyvinyl acetal resin, mixing them, and drying to adjust the water content is preferable.

The polyvinyl acetal resin composition can be suitably used for general applications using a polyvinyl acetal resin, and for example, a coating solution for producing ceramic molded articles, metal pastes, thermally developable photosensitive materials, paints, inks, reflective sheets, and the like can be obtained. In addition, the adhesive composition can be used as an adhesive for a film facing a display, an interlayer adhesive for a ceramic laminate, a liquid glue, a solid glue, or the like.

The polyvinyl acetal resin composition, the organic solvent, and the inorganic fine particles are mixed to prepare an inorganic fine particle dispersion slurry composition.

The organic solvent is not particularly limited, and examples thereof include, for example, the polyvinyl acetal resin as long as it can be dissolved therein: ketones such as acetone, methyl ethyl ketone, dipropyl ketone, and diisobutyl ketone. Further, examples thereof include: alcohols such as methanol, ethanol, isopropanol and butanol, aromatic hydrocarbons such as toluene and xylene, and the like. Further, there may be mentioned: 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, 2-ethylhexyl acetate, and 2-ethylhexyl butyrate. Further, examples thereof include: methyl cellosolve, ethyl cellosolve, butyl cellosolve, terpineol, dihydroterpineol, butyl cellosolve acetate, butyl carbitol acetate, terpineol acetate, dihydroterpineol acetate, and the like. In particular, alcohols, ketones, aromatic hydrocarbons, and mixed solvents thereof are preferable from the viewpoint of coatability and drying properties. Among them, a mixed solvent of ethanol and toluene and a mixed solvent of methyl ethyl ketone and toluene are more preferable.

The content of the organic solvent in the inorganic fine particle-dispersed slurry composition is set according to the type of the polyvinyl acetal resin used, and is not particularly limited, but if it is too small, it is difficult to exhibit the solubility required for kneading. If the amount is too large, the viscosity of the slurry composition may be too low, and the handling properties may be deteriorated when producing a ceramic green sheet. Therefore, the content of the organic solvent is preferably 20% by weight or more and 80% by weight or less.

The inorganic fine particle-dispersed slurry composition contains inorganic fine particles.

The inorganic fine particles are not particularly limited, and examples thereof include ceramic powder, glass powder, and metal fine particles.

The ceramic powder is not particularly limited, and examples thereof include powders of oxides, carbides, nitrides, borides, sulfides, and the like of metals or non-metals used for the production of ceramics. Specific examples thereof include: li, K, mg, B, al, si, cu, ca, sr, ba, zn, cd, ga, in, Y, oxides, carbides, nitrides, borides, sulfides of lanthanides, actinides, ti, zr, hf, bi, V, nb, ta, W, mn, fe, co, ni, and the like. These ceramic powders may be used alone or in the form of a mixture of 2 or more kinds.

Examples include: barium titanate, aluminum nitride (AlN), silicon nitride (Si 3N 4), silicon carbide (SiC), aluminum oxide (Al 2O 3), copper oxide (CuO), spinel-based compounds, ferrite, zirconium oxide, zirconium, barium zirconate, calcium zirconate, titanium oxide, barium titanate, strontium titanate, calcium titanate, magnesium titanate, zinc titanate, lanthanum titanate, neodymium titanate, lead zirconate titanate (japanese text コ lead), aluminum oxynitride, silicon nitride, boron carbide, barium stannate, calcium stannate, magnesium silicate, mullite, steatite, cordierite, forsterite, and the like.

The glass powder is not particularly limited, and examples thereof include: bismuth oxide glass, silicate glass, glass powder such as lead glass, zinc glass, and boron glass, glass powder of various silicon oxides such as CaO-Al ₂O₃-SiO₂ system, mgO-Al ₂O₃-SiO₂ system, and LiO ₂-Al₂O₃-SiO₂ system, and the like.

Further, as the glass powder, it is also possible to use: snO-B ₂O₃-P₂O₅-Al₂O₃ mixture, pbO-B ₂O₃-SiO₂ mixture, baO-ZnO-B ₂O₃-SiO₂ mixture, znO-Bi ₂O₃-B₂O₃-SiO₂ mixture, bi ₂O₃-B₂O₃ -BaO-CuO mixture, bi ₂O₃-ZnO-B₂O₃-Al₂O₃ -SrO mixture, znO-Bi ₂O₃-B₂O₃ mixture, bi ₂O₃-SiO₂ mixture, P ₂O₅-Na₂O-CaO-BaO-Al₂O₃-B₂O₃ mixture, P ₂O₅ -SnO mixture, P ₂O₅-SnO-B₂O₃ mixture, P ₂O₅-SnO-SiO₂ mixture, cuO-P ₂O₅ -RO mixture, siO ₂-B₂O₃-ZnO-Na₂O-Li₂O-NaF-V₂O₅ mixture, P ₂O₅-ZnO-SnO-R₂ O-RO mixture, B ₂O₃-SiO₂ -ZnO mixture, B ₂O₃-SiO₂-Al₂O₃-ZrO₂ mixture, siO ₂-B₂O₃-ZnO-R₂ O-RO mixture, siO ₂-B₂O₃-Al₂O₃-RO-R₂ O mixture, srO-ZnO-P ₂O₅ mixture, srO-ZnO-P ₂O₅ mixture, baO-ZnO-B ₂O₃-SiO₂ mixture, and the like. R is an element selected from Zn, ba, ca, mg, sr, sn, ni, fe and Mn.

Particularly, lead-free glass powders such as glass powders of PbO-B ₂O₃-SiO₂ mixtures, lead-free BaO-ZnO-B ₂O₃-SiO₂ mixtures, and ZnO-Bi ₂O₃-B₂O₃-SiO₂ mixtures are preferable.

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

In addition, various carbon blacks, carbon nanotubes, and the like may be used in addition to the metal complex. Further, ITO, FTO, niobium oxide, vanadium oxide, tungsten oxide, lanthanum strontium manganate, japanese, lanthanum strontium cobalt ferrite, yttrium stabilized zirconia, gadolinium doped ceria, nickel oxide, lanthanum chromate, etc. may be used.

The content of the inorganic fine particles in the inorganic fine particle-dispersed slurry composition is not particularly limited, but is preferably 10% by weight or more, more preferably 15% by weight or more, preferably 90% by weight or less, more preferably 85% by weight or less. By setting the viscosity in the above range, the coating composition can have sufficient viscosity and excellent coating properties, and the inorganic fine particles can be made excellent in dispersibility. The content of the inorganic fine particles is preferably 10 to 90% by weight, more preferably 15 to 85% by weight.

The inorganic fine particle-dispersed slurry composition contains a plasticizer.

Examples of the plasticizer include: for example, monomethyl adipate, di (butoxyethyl) adipate, dibutoxyethoxyethyl adipate, triethylene glycol bis (2-ethylhexanoate), triethylene glycol dihexanoate, acetyl triethyl citrate, cetyl tributyl citrate, dibutyl sebacate, butyl benzyl phthalate, diisononyl adipate, diisodecyl phthalate, glyceryl tripropionate, pentaerythritol tetraacetate, di-2-ethylhexyl phthalate, glyceryl triacetate, and the like.

Among them, triethylene glycol bis (2-ethylhexanoate), butyl benzyl phthalate, diisononyl adipate, diisodecyl phthalate, glyceryl tripropionate, pentaerythritol tetraacetate, di-2-ethylhexyl phthalate and the like are preferable.

The boiling point of the plasticizer is preferably 240 ℃ or higher, and preferably less than 390 ℃. By setting the boiling point to 240 ℃ or higher, the mixture is easily evaporated in the drying step, and 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 is not particularly limited, but is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, preferably 3% by weight or less, more preferably 2.5% by weight or less. The content of the plasticizer is preferably 0.1 to 3.0% by weight, more preferably 0.2 to 2.5% by weight. By setting the range to the above range, the firing residue of the plasticizer can be reduced.

The fine particle dispersion slurry composition may contain other resins such as a polyvinyl acetal resin, an acrylic resin, and ethylcellulose in addition to the polyvinyl acetal resin composition within a range that does not impair the above-described effects. In such a case, the content of the polyvinyl acetal resin composition is preferably 50% by weight or more with respect to the total binder resin.

The viscosity of the inorganic fine particle-dispersed slurry composition is not particularly limited, but is preferably 0.1pa·s or more, and preferably 100pa·s or less, when measured at 20 ℃ using a type B viscometer with a probe rotation speed set at 5 rpm.

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

The method for producing the inorganic fine particle-dispersed slurry composition is not particularly limited, and conventionally known stirring methods are exemplified, and specifically, examples thereof include: and a method in which the polyvinyl acetal resin composition, the inorganic fine particles, and optionally, an organic solvent, a plasticizer, and other components are stirred by a bead mill or the like.

The inorganic fine particle-dispersed sheet can be produced by applying the above-mentioned inorganic fine particle-dispersed slurry composition to a support film subjected to a single-sided release treatment, drying an organic solvent, and forming the sheet-like inorganic fine particle-dispersed sheet.

The thickness of the inorganic fine particle-dispersed sheet is preferably 0.5 μm or more, and more preferably 3 μm or less.

The support film used in the production of the inorganic fine particle-dispersed sheet 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 knife coater or the like, and the resulting inorganic fine particle dispersion sheet-forming film can be stored and supplied in a state of being wound into a roll.

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

The thickness of the support film is, for example, preferably 20 μm or more and preferably 100 μm or less.

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 above inorganic fine particle-dispersed slurry composition and the inorganic fine particle-dispersed sheet are used for dielectric green sheets and electrode pastes, whereby a multilayer ceramic capacitor can be produced.

The method for manufacturing a laminated ceramic capacitor preferably includes: printing a conductive paste on the inorganic fine particle dispersion sheet and drying the conductive paste to produce a dielectric sheet; and 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, alloys thereof, and the like. These conductive powders may be used alone or in combination of 2 or more.

As the binder resin and the organic solvent used for the conductive paste, the same binder resin and the same organic solvent as those used in the inorganic fine particle-dispersed slurry composition can be used.

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

In the above method for manufacturing a laminated ceramic capacitor, the dielectric sheet on which the conductive paste is printed is laminated, degreased and fired, and then an external electrode is provided, thereby obtaining a laminated ceramic capacitor having a dielectric layer and an electrode layer.

In addition, a laminated ceramic capacitor having a dielectric layer or an electrode layer formed by using the inorganic fine particle dispersion slurry composition is also one of the present invention.

Effects of the invention

According to the present invention, a polyvinyl acetal resin composition which is particularly excellent in thermal decomposition properties and which can exhibit high solvent solubility can be provided. In addition, an inorganic fine particle dispersion slurry composition and a laminated ceramic capacitor 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.

Example 1

(Preparation of polyvinyl acetal aqueous resin PVB 1)

To 300g of a polyvinyl alcohol resin (average polymerization degree 3300, saponification degree 99 mol%), 3000g of pure water was added, and the mixture was stirred at 90℃for 2 hours to dissolve the mixture. The solution was cooled to 40℃and 200g of hydrochloric acid having a concentration of 35% by weight and 160g of n-butyraldehyde were added thereto to carry out an acetalization reaction, whereby a reaction product was precipitated. Then, the reaction was completed by maintaining at 40℃for 3 hours, and neutralization, washing with water and dehydration were carried out by a conventional method to obtain an aqueous polyvinyl acetal resin PVB1. The water content of the polyvinyl acetal aqueous resin PVB1 was 60% by weight when measured by an infrared moisture meter.

(Preparation of polyvinyl acetal resin composition)

To the obtained polyvinyl acetal aqueous resin PVB1, citric acid was added so as to be 3.2 parts by weight based on 100 parts by weight of the polyvinyl acetal resin composition, and the mixture was dried at 40 ℃ for 48 hours to obtain a polyvinyl acetal resin composition.

The obtained polyvinyl acetal resin composition was dissolved in DMSO-D ⁶ (dimethyl sulfoxide), and analyzed by ¹ H-NMR (nuclear magnetic resonance spectroscopy), and the amounts of acetal group, acetyl group and hydroxyl group were shown in table 1.

The water content was measured by an infrared hygrometer (MX-50, manufactured by A & D Co.). The measurement of the water content was performed at 125℃until the water content was changed to 0.05%/min.

The citric acid content was measured by ion chromatography, and the results are shown in table 1. As the measuring apparatus, an ion chromatography system ICS900 (manufactured by Thermo FISHER SCIENTIFIC Co., ltd., column: ionpac AS (4. Phi. Times.250 mm), and a detector: conductivity meter) was used.

Example 2

A polyvinyl acetal resin composition was obtained in the same manner as in example 1, except that tartaric acid was used instead of citric acid.

Example 3

A polyvinyl acetal resin composition was obtained in the same manner as in example 1, except that malic acid was used instead of citric acid.

Comparative example 1

A polyvinyl acetal resin composition was obtained in the same manner as in example 1, except that citric acid was not added.

Comparative example 2

A polyvinyl acetal resin composition was obtained in the same manner as in example 1, except that tartaric acid was used instead of citric acid and the water content was adjusted to 6.5% by weight by drying at 40 ℃ for 26 hours.

Example 4

(Preparation of polyvinyl acetal aqueous resin PVB 2)

A polyvinyl acetal aqueous resin PVB2 was obtained in the same manner as in example 1, except that a polyvinyl alcohol resin (average polymerization degree 1700, saponification degree 99 mol%) was used.

A polyvinyl acetal resin composition was obtained in the same manner as in example 1, except that a polyvinyl acetal aqueous resin PVB2 was used.

Example 5

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that tartaric acid was used instead of citric acid.

Example 6

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that malic acid was used instead of citric acid.

Example 7

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that pentaerythritol was used instead of citric acid.

Example 8

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that pentaerythritol tetraacetate was used instead of citric acid.

Example 9

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that 16 parts by weight of pentaerythritol tetraacetate was used instead of citric acid.

Example 10

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that instead of citric acid, polyglycerol having a glycerol unit average number n of 6 was used, and the water content was adjusted to 1.0% by weight by drying at 40 ℃ for 46 hours.

Example 11

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that oxalic acid was used instead of citric acid.

Example 12

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that tartronic acid was used instead of citric acid.

Example 13

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that malonic acid was used instead of citric acid.

Example 14

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that glutaric acid was used instead of citric acid.

Example 15

A polyvinyl acetal resin composition was obtained in the same manner as in example 10 except that 2.5 parts by weight of polyglycerol was used.

Example 16

A polyvinyl acetal resin composition was obtained in the same manner as in example 5 except that 25.0 parts by weight of tartaric acid was used.

Comparative example 3

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that citric acid was not added.

Comparative example 4

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that 1.6 parts by weight of triethylene glycol di (2-ethylhexanoate) was used instead of citric acid.

Comparative example 5

In a reaction vessel, 50g of water was added to 5g of a powdery polyvinyl alcohol resin (average polymerization degree 1700, saponification degree 99 mol%) and heated and stirred to obtain a polyvinyl alcohol aqueous solution. To 55g of the obtained aqueous polyvinyl alcohol solution was added 1.0g of citric acid and 4.8g of n-butyraldehyde. Carbon dioxide was injected into the reaction vessel, the temperature in the vessel was adjusted to 130 ℃, and the internal pressure of the vessel was adjusted to 2.0MPa using a pressure adjusting valve. After the reaction was performed while stirring at 130℃for 2 hours, the reaction part was cooled to room temperature to obtain a resin composition containing a polyvinyl acetal resin PVB 5.

The citric acid content of the obtained polyvinyl acetal resin composition was measured by ion chromatography, and as a result, the citric acid content was 14 parts by weight based on 100 parts by weight of the polyvinyl acetal resin.

Comparative example 6

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that tartaric acid was used instead of citric acid and the water content was adjusted to 20.0 wt% by drying at 40 ℃ for 10 hours.

Comparative example 7

A polyvinyl acetal resin composition was obtained in the same manner as in example 4, except that formamide was used instead of citric acid, and the water content was adjusted to 1.2% by weight by drying at 40 ℃ for 42 hours.

Example 17

(Preparation of polyvinyl acetal aqueous resin PVB 3)

A polyvinyl acetal aqueous resin PVB3 was obtained in the same manner as in example 1, except that a polyvinyl alcohol resin (average polymerization degree 800, saponification degree 98.5 mol%) was used.

A polyvinyl acetal resin composition was obtained in the same manner as in example 1, except that a polyvinyl acetal aqueous resin PVB3 was used.

Example 18

A polyvinyl acetal resin composition was obtained in the same manner as in example 17, except that tartaric acid was used instead of citric acid.

Example 19

A polyvinyl acetal resin composition was obtained in the same manner as in example 17, except that malic acid was used instead of citric acid.

Example 20

To the polyvinyl acetal aqueous resin PVB3, 3.2 parts by weight of citric acid was added to 100 parts by weight of the polyvinyl acetal resin, and the mixture was dried at 40 ℃ for 30 hours, whereby the water content was adjusted to 4.0% by weight, to obtain a polyvinyl acetal resin composition.

Comparative example 8

A polyvinyl acetal resin composition was obtained in the same manner as in example 17, except that citric acid was not added.

Example 21

(Preparation of polyvinyl acetal aqueous resin PVB 4)

A polyvinyl acetal resin PVB4 was obtained in the same manner as in example 1, except that a polyvinyl alcohol resin (average polymerization degree: 850, saponification degree: 94.8 mol%) was used, and 300g of hydrochloric acid and 180g of n-butyraldehyde were used, each having a concentration of 35 wt%.

To the polyvinyl acetal aqueous resin PVB4, 3.2 parts by weight of tartaric acid was added to 100 parts by weight of the polyvinyl acetal resin, and the mixture was dried at 40 ℃ for 48 hours, whereby the water content was adjusted to 1.0% by weight, to obtain a polyvinyl acetal resin composition.

Comparative example 9

A polyvinyl acetal resin composition was obtained in the same manner as in example 21, except that tartaric acid was not added.

Example 22

(Production of carboxylic acid-modified polyvinyl alcohol resin)

Vinyl acetate and crotonic acid were set at a molar ratio of 99.88:0.12, in the presence of a radical polymerization initiator, by a conventional method, 30 parts by weight of the vinyl acetate copolymer thus obtained was dissolved in 60 parts by weight of methanol. Then, 0.4 parts by weight of a 45% by weight aqueous sodium hydroxide solution was added, followed by stirring for 1 hour, neutralization was performed with concentrated acetic acid, and the precipitated product was washed with methanol. Thus, a carboxylic acid-modified polyvinyl alcohol resin having a structural unit represented by the formula (b-2) (in the formula (b-2), R ^3b is a methyl group, R ^4b is a hydrogen atom, R ^5b is a hydrogen atom, R ^6b is a single bond, and X ^3b is a hydrogen atom) was obtained. As a result of measurement in accordance with JIS K6726, the residual acetyl group amount was 5.5 mol%, and the average polymerization degree was 800. Further, the content of the structural unit having a carboxyl group (carboxyl group amount) was 0.1 mol% as measured by FT-IR.

To 300g of the obtained carboxylic acid-modified polyvinyl alcohol resin, 3000g of pure water was added, and the mixture was stirred at 90℃for 2 hours to dissolve the resin. The solution was cooled to 40℃and 270g of hydrochloric acid having a concentration of 35% by weight and 240g of n-butyraldehyde were added thereto to carry out an acetalization reaction, whereby a reaction product was precipitated. Then, the reaction was completed by maintaining at 40℃for 3 hours, and neutralization, washing with water and dehydration were carried out by a conventional method to obtain an aqueous polyvinyl acetal resin PVB5. The water content of the polyvinyl acetal aqueous resin PVB5 was 60% by weight when measured by an infrared moisture meter.

To the obtained polyvinyl acetal aqueous resin PVB5, tartaric acid was added so as to be 3.2 parts by weight based on 100 parts by weight of the polyvinyl acetal resin composition, and the mixture was dried at 40 ℃ for 28 hours, and the water content was adjusted to 5.0 parts by weight, to obtain a polyvinyl acetal resin composition.

Comparative example 10

A polyvinyl acetal resin composition was obtained in the same manner as in example 22, except that tartaric acid was not added.

Example 23

To 193g of a modified polyvinyl alcohol resin (average degree of polymerization 1700, residual acetyl group content 12 mol%, ethylene content 10 mol%) was added 2900g of pure water, and the mixture was stirred at 90℃for 2 hours to dissolve the same. The solution was cooled to 20℃and 40g of hydrochloric acid having a concentration of 35% by weight and 125g of n-butyraldehyde were added thereto to carry out an acetalization reaction, whereby a reaction product was precipitated. Then, the reaction was completed after holding at 30℃for 5 hours, and neutralization, washing with water and dehydration were carried out by a conventional method to obtain an aqueous polyvinyl acetal resin PVB6. The water content of the polyvinyl acetal aqueous resin PVB6 was 60% by weight when measured by an infrared moisture meter.

To the obtained polyvinyl acetal aqueous resin PVB6, tartaric acid was added so as to be 3.2 parts by weight based on 100 parts by weight of the polyvinyl acetal resin composition, and the mixture was dried at 40 ℃ for 46 hours, and the water content was adjusted to 1.0 part by weight, to obtain a polyvinyl acetal resin composition.

Comparative example 11

A polyvinyl acetal resin composition was obtained in the same manner as in example 23, except that tartaric acid was not added.

Example 24

To 193g of a modified polyvinyl alcohol resin (average degree of polymerization: 800, residual acetyl group content: 7 mol%, ethylene content: 5 mol%) was added 2900g of pure water, and the mixture was stirred at 90℃for 2 hours to dissolve the same. The solution was cooled to 20℃and 20g of hydrochloric acid having a concentration of 35% by weight and 110g of n-butyraldehyde were added thereto to carry out an acetalization reaction, whereby a reaction product was precipitated. Then, the reaction was completed after holding at 30℃for 5 hours, and neutralization, washing with water and dehydration were carried out by a conventional method to obtain an aqueous polyvinyl acetal resin PVB7. The water content of the polyvinyl acetal aqueous resin PVB7 was 60% by weight when measured by an infrared moisture meter.

To the obtained polyvinyl acetal aqueous resin PVB7, tartaric acid was added so as to be 3.2 parts by weight based on 100 parts by weight of the polyvinyl acetal resin composition, and the mixture was dried at 40 ℃ for 28 hours, and the water content was adjusted to 5.0 parts by weight, to obtain a polyvinyl acetal resin composition.

Comparative example 12

A polyvinyl acetal resin composition was obtained in the same manner as in example 24, except that tartaric acid was not added.

< Evaluation >

The following evaluation was performed on the obtained polyvinyl acetal resin composition. The results are shown in tables 1 to 5.

(1) Weight average molecular weight (Mw)

The obtained polyvinyl acetal resin was dissolved in tetrahydrofuran at a concentration of 0.05 wt%, and measured by a GPC device HLC-8220 (manufactured by eastern co.), and the weight average molecular weight Mw was calculated from the measurement result obtained by using a molecular weight calibration curve prepared by monodisperse polystyrene standard samples. As the column, column TSKgel SuperHZM-H (manufactured by Tosoh corporation) was used.

(2) Residual amount of

After drying the polyvinyl acetal resin composition at 60℃for 2 hours using a vacuum dryer, 8.0000mg of the composition was measured in an alumina pan, and the temperature was raised from room temperature to 800℃at 10℃per minute using TG/DTA (SDT-Q600, manufactured by T.A. instruments Japan Co., ltd.) and maintained at 800℃for 30 minutes, and after cooling to room temperature, the alumina pan was measured by a precision balance (manufactured by A & D, BA-6 TE), and the value obtained by subtracting the weight of the alumina pan before the temperature was used as a residual amount W.

(3) Reduction rate

The polyvinyl acetal resin compositions obtained in comparative examples 1,3 and 8 to 12 were dried at 60℃for 2 hours using a vacuum dryer, then 8.0000mg was measured in an alumina pan, the temperature was raised from room temperature to 800℃at 10℃per minute using TG/DTA (manufactured by T.A. instruments Japan Co., ltd., SDT-Q600), the temperature was kept at 800℃for 30 minutes, the temperature was cooled to room temperature, the alumina pan was measured by a precision balance (manufactured by A & D, BA-6 TE), and the values obtained by subtracting the weight of the alumina pan before the temperature rise were respectively set as WB (1), WB (2) and WB

(3) WB (4), WB (5), WB (6) and WB (7). The residual amount of each example measured above WAs designated as WA, and the reduction rate WAs calculated using the following calculation formula.

(WB-WA)×100/WB

In calculation, WB (1) was used in examples 1 to 3 and comparative example 2 (comparative example 1), WB (2) was used in examples 4 to 16 and comparative examples 4 to 7 (comparative example 3), WB (3) was used in examples 17 to 20 (comparative example 8), WB (4) was used in example 21 (comparative example 9), WB (5) was used in example 22 (comparative example 10), WB (6) was used in example 23 (comparative example 11), and WB (7) was used in example 24 (comparative example 12).

(4) Solvent solubility

The weight ratio of ethanol to toluene was prepared to be 1:9, the weight ratio of the mixed solvent A to the ethanol to the toluene is 5:5, and a mixed solvent B. In a sealed glass container, 30g of a solution was prepared by mixing the polyvinyl acetal resin composition and the mixed solvent A, B or C so that the polyvinyl acetal resin content became 9% by weight. The mixture was mixed for 5 hours using a hot stirrer so that the temperature of the solution became 60 ℃, and the state of the solution immediately after the mixing was visually confirmed, and the evaluation was performed according to the following criteria.

A: without undissolved, the solution was transparent.

B: without dissolution, the solution was blue.

C: undissolved, or cloudy solution was present.

TABLE 1

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TABLE 4

TABLE 5

Industrial applicability

Claims

1. A polyvinyl acetal resin composition having a water content of 5.0 wt.% or less,

The polyvinyl acetal resin composition contains a polyvinyl acetal resin and a compound A containing carbon atoms, hydrogen atoms and oxygen atoms, wherein the ratio of the number of oxygen atoms to the total number of atoms, i.e., the number of oxygen atoms/the total number of atoms, is 0.18 or more.

2. The polyvinyl acetal resin composition according to claim 1, wherein,

The polyvinyl acetal resin composition contains 2.8 to 20 parts by weight of compound A with respect to 100 parts by weight of the polyvinyl acetal resin.

3. The polyvinyl acetal resin composition according to claim 1 or 2, wherein,

When the solubility parameter value of the polyvinyl acetal resin calculated by the Fedors method is S1 and the solubility parameter of the compound a is S2, the absolute value of the difference between S1 and S2 is 9.0 (cal/cm ³)^0.5 or less.

4. The polyvinyl acetal resin composition according to any of claims 1 to 3, wherein,

The molecular weight of the compound A is more than 90 and less than 450.

5. The polyvinyl acetal resin composition according to any one of claims 1 to 4, wherein,

The compound A is at least 1 selected from the compounds represented by the following formula (1) and the compounds represented by the following formula (2),

R¹-R²—R³ (1)

R⁴-R⁵-R⁶ (2)

In the formula (1), R ¹ and R ³ represent a carboxyl group or a salt thereof, R ² represents a single bond, a 2-valent group containing a carbon atom, a hydrogen atom and an oxygen atom, which is optionally substituted with a hydroxyl group and a carboxyl group or a salt thereof,

6. The polyvinyl acetal resin composition according to claim 5, wherein,

In the formula (1), R ² is a single bond, a linear alkylene group having 1 to 6 carbon atoms and having at least 1 of a hydroxyl group, a carboxyl group or a salt thereof, or a branched alkylene group having 3 to 6 carbon atoms and having at least 1 of a hydroxyl group, a carboxyl group or a salt thereof.

7. The polyvinyl acetal resin composition according to claim 5 or 6, wherein,

In the formula (2), R ⁵ is a linear alkylene group having 1 to 6 carbon atoms and having at least 1 of a hydroxyl group, an acetyl group, an acetoxy group, a carboxyl group or a salt thereof, a branched alkylene group having 3 to 6 carbon atoms and having at least 1 of a hydroxyl group, an acetyl group, an acetoxy group, a carboxyl group or a salt thereof, or a glycerol unit having a repeating number of 2 to 11.

8. The polyvinyl acetal resin composition according to any one of claims 5 to 7, wherein,

The compound represented by the formula (1) is at least 1 compound selected from tartaric acid, malic acid, citric acid and salts thereof.

9. The polyvinyl acetal resin composition according to any one of claims 5 to 8, wherein,

The compound represented by the formula (2) is at least 1 compound selected from pentaerythritol and pentaerythritol tetraacetate.

10. The polyvinyl acetal resin composition according to any one of claims 1 to 9, wherein,

Y values represented by the following formula are 6.3X10 ^-9 to 45.0X10 ^-9,

Y＝((W_A÷M_A×O_R)÷(100-W_W))÷(M_PVB÷M_A)÷S^0.4

M _A: molecular weight of Compound A

O _R: the ratio of the number of oxygen atoms to the total number of atoms in the compound A, i.e., the number of oxygen atoms/the total number of atoms

W _W: water content of polyvinyl acetal resin composition

M _PVB: weight average molecular weight of polyvinyl acetal resin

11. An inorganic fine particle-dispersed slurry composition comprising the polyvinyl acetal resin composition according to any one of claims 1 to 10, an organic solvent, and inorganic fine particles.

12. The inorganic fine particle-dispersed slurry composition according to claim 11, further comprising a plasticizer.

13. The inorganic fine particle-dispersed slurry composition according to claim 11 or 12, wherein,

The inorganic particles are barium titanate powder or nickel powder.

14. A laminated ceramic capacitor comprising a dielectric layer or an electrode layer formed by using the inorganic fine particle-dispersed slurry composition according to any one of claims 11 to 13.